linux/net/ipv4/tcp.c

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/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Implementation of the Transmission Control Protocol(TCP).
*
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Mark Evans, <evansmp@uhura.aston.ac.uk>
* Corey Minyard <wf-rch!minyard@relay.EU.net>
* Florian La Roche, <flla@stud.uni-sb.de>
* Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
* Linus Torvalds, <torvalds@cs.helsinki.fi>
* Alan Cox, <gw4pts@gw4pts.ampr.org>
* Matthew Dillon, <dillon@apollo.west.oic.com>
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
* Jorge Cwik, <jorge@laser.satlink.net>
*
* Fixes:
* Alan Cox : Numerous verify_area() calls
* Alan Cox : Set the ACK bit on a reset
* Alan Cox : Stopped it crashing if it closed while
* sk->inuse=1 and was trying to connect
* (tcp_err()).
* Alan Cox : All icmp error handling was broken
* pointers passed where wrong and the
* socket was looked up backwards. Nobody
* tested any icmp error code obviously.
* Alan Cox : tcp_err() now handled properly. It
* wakes people on errors. poll
* behaves and the icmp error race
* has gone by moving it into sock.c
* Alan Cox : tcp_send_reset() fixed to work for
* everything not just packets for
* unknown sockets.
* Alan Cox : tcp option processing.
* Alan Cox : Reset tweaked (still not 100%) [Had
* syn rule wrong]
* Herp Rosmanith : More reset fixes
* Alan Cox : No longer acks invalid rst frames.
* Acking any kind of RST is right out.
* Alan Cox : Sets an ignore me flag on an rst
* receive otherwise odd bits of prattle
* escape still
* Alan Cox : Fixed another acking RST frame bug.
* Should stop LAN workplace lockups.
* Alan Cox : Some tidyups using the new skb list
* facilities
* Alan Cox : sk->keepopen now seems to work
* Alan Cox : Pulls options out correctly on accepts
* Alan Cox : Fixed assorted sk->rqueue->next errors
* Alan Cox : PSH doesn't end a TCP read. Switched a
* bit to skb ops.
* Alan Cox : Tidied tcp_data to avoid a potential
* nasty.
* Alan Cox : Added some better commenting, as the
* tcp is hard to follow
* Alan Cox : Removed incorrect check for 20 * psh
* Michael O'Reilly : ack < copied bug fix.
* Johannes Stille : Misc tcp fixes (not all in yet).
* Alan Cox : FIN with no memory -> CRASH
* Alan Cox : Added socket option proto entries.
* Also added awareness of them to accept.
* Alan Cox : Added TCP options (SOL_TCP)
* Alan Cox : Switched wakeup calls to callbacks,
* so the kernel can layer network
* sockets.
* Alan Cox : Use ip_tos/ip_ttl settings.
* Alan Cox : Handle FIN (more) properly (we hope).
* Alan Cox : RST frames sent on unsynchronised
* state ack error.
* Alan Cox : Put in missing check for SYN bit.
* Alan Cox : Added tcp_select_window() aka NET2E
* window non shrink trick.
* Alan Cox : Added a couple of small NET2E timer
* fixes
* Charles Hedrick : TCP fixes
* Toomas Tamm : TCP window fixes
* Alan Cox : Small URG fix to rlogin ^C ack fight
* Charles Hedrick : Rewrote most of it to actually work
* Linus : Rewrote tcp_read() and URG handling
* completely
* Gerhard Koerting: Fixed some missing timer handling
* Matthew Dillon : Reworked TCP machine states as per RFC
* Gerhard Koerting: PC/TCP workarounds
* Adam Caldwell : Assorted timer/timing errors
* Matthew Dillon : Fixed another RST bug
* Alan Cox : Move to kernel side addressing changes.
* Alan Cox : Beginning work on TCP fastpathing
* (not yet usable)
* Arnt Gulbrandsen: Turbocharged tcp_check() routine.
* Alan Cox : TCP fast path debugging
* Alan Cox : Window clamping
* Michael Riepe : Bug in tcp_check()
* Matt Dillon : More TCP improvements and RST bug fixes
* Matt Dillon : Yet more small nasties remove from the
* TCP code (Be very nice to this man if
* tcp finally works 100%) 8)
* Alan Cox : BSD accept semantics.
* Alan Cox : Reset on closedown bug.
* Peter De Schrijver : ENOTCONN check missing in tcp_sendto().
* Michael Pall : Handle poll() after URG properly in
* all cases.
* Michael Pall : Undo the last fix in tcp_read_urg()
* (multi URG PUSH broke rlogin).
* Michael Pall : Fix the multi URG PUSH problem in
* tcp_readable(), poll() after URG
* works now.
* Michael Pall : recv(...,MSG_OOB) never blocks in the
* BSD api.
* Alan Cox : Changed the semantics of sk->socket to
* fix a race and a signal problem with
* accept() and async I/O.
* Alan Cox : Relaxed the rules on tcp_sendto().
* Yury Shevchuk : Really fixed accept() blocking problem.
* Craig I. Hagan : Allow for BSD compatible TIME_WAIT for
* clients/servers which listen in on
* fixed ports.
* Alan Cox : Cleaned the above up and shrank it to
* a sensible code size.
* Alan Cox : Self connect lockup fix.
* Alan Cox : No connect to multicast.
* Ross Biro : Close unaccepted children on master
* socket close.
* Alan Cox : Reset tracing code.
* Alan Cox : Spurious resets on shutdown.
* Alan Cox : Giant 15 minute/60 second timer error
* Alan Cox : Small whoops in polling before an
* accept.
* Alan Cox : Kept the state trace facility since
* it's handy for debugging.
* Alan Cox : More reset handler fixes.
* Alan Cox : Started rewriting the code based on
* the RFC's for other useful protocol
* references see: Comer, KA9Q NOS, and
* for a reference on the difference
* between specifications and how BSD
* works see the 4.4lite source.
* A.N.Kuznetsov : Don't time wait on completion of tidy
* close.
* Linus Torvalds : Fin/Shutdown & copied_seq changes.
* Linus Torvalds : Fixed BSD port reuse to work first syn
* Alan Cox : Reimplemented timers as per the RFC
* and using multiple timers for sanity.
* Alan Cox : Small bug fixes, and a lot of new
* comments.
* Alan Cox : Fixed dual reader crash by locking
* the buffers (much like datagram.c)
* Alan Cox : Fixed stuck sockets in probe. A probe
* now gets fed up of retrying without
* (even a no space) answer.
* Alan Cox : Extracted closing code better
* Alan Cox : Fixed the closing state machine to
* resemble the RFC.
* Alan Cox : More 'per spec' fixes.
* Jorge Cwik : Even faster checksumming.
* Alan Cox : tcp_data() doesn't ack illegal PSH
* only frames. At least one pc tcp stack
* generates them.
* Alan Cox : Cache last socket.
* Alan Cox : Per route irtt.
* Matt Day : poll()->select() match BSD precisely on error
* Alan Cox : New buffers
* Marc Tamsky : Various sk->prot->retransmits and
* sk->retransmits misupdating fixed.
* Fixed tcp_write_timeout: stuck close,
* and TCP syn retries gets used now.
* Mark Yarvis : In tcp_read_wakeup(), don't send an
* ack if state is TCP_CLOSED.
* Alan Cox : Look up device on a retransmit - routes may
* change. Doesn't yet cope with MSS shrink right
* but it's a start!
* Marc Tamsky : Closing in closing fixes.
* Mike Shaver : RFC1122 verifications.
* Alan Cox : rcv_saddr errors.
* Alan Cox : Block double connect().
* Alan Cox : Small hooks for enSKIP.
* Alexey Kuznetsov: Path MTU discovery.
* Alan Cox : Support soft errors.
* Alan Cox : Fix MTU discovery pathological case
* when the remote claims no mtu!
* Marc Tamsky : TCP_CLOSE fix.
* Colin (G3TNE) : Send a reset on syn ack replies in
* window but wrong (fixes NT lpd problems)
* Pedro Roque : Better TCP window handling, delayed ack.
* Joerg Reuter : No modification of locked buffers in
* tcp_do_retransmit()
* Eric Schenk : Changed receiver side silly window
* avoidance algorithm to BSD style
* algorithm. This doubles throughput
* against machines running Solaris,
* and seems to result in general
* improvement.
* Stefan Magdalinski : adjusted tcp_readable() to fix FIONREAD
* Willy Konynenberg : Transparent proxying support.
* Mike McLagan : Routing by source
* Keith Owens : Do proper merging with partial SKB's in
* tcp_do_sendmsg to avoid burstiness.
* Eric Schenk : Fix fast close down bug with
* shutdown() followed by close().
* Andi Kleen : Make poll agree with SIGIO
* Salvatore Sanfilippo : Support SO_LINGER with linger == 1 and
* lingertime == 0 (RFC 793 ABORT Call)
* Hirokazu Takahashi : Use copy_from_user() instead of
* csum_and_copy_from_user() if possible.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or(at your option) any later version.
*
* Description of States:
*
* TCP_SYN_SENT sent a connection request, waiting for ack
*
* TCP_SYN_RECV received a connection request, sent ack,
* waiting for final ack in three-way handshake.
*
* TCP_ESTABLISHED connection established
*
* TCP_FIN_WAIT1 our side has shutdown, waiting to complete
* transmission of remaining buffered data
*
* TCP_FIN_WAIT2 all buffered data sent, waiting for remote
* to shutdown
*
* TCP_CLOSING both sides have shutdown but we still have
* data we have to finish sending
*
* TCP_TIME_WAIT timeout to catch resent junk before entering
* closed, can only be entered from FIN_WAIT2
* or CLOSING. Required because the other end
* may not have gotten our last ACK causing it
* to retransmit the data packet (which we ignore)
*
* TCP_CLOSE_WAIT remote side has shutdown and is waiting for
* us to finish writing our data and to shutdown
* (we have to close() to move on to LAST_ACK)
*
* TCP_LAST_ACK out side has shutdown after remote has
* shutdown. There may still be data in our
* buffer that we have to finish sending
*
* TCP_CLOSE socket is finished
*/
#define pr_fmt(fmt) "TCP: " fmt
#include <crypto/hash.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/poll.h>
#include <linux/inet_diag.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/skbuff.h>
#include <linux/scatterlist.h>
#include <linux/splice.h>
#include <linux/net.h>
#include <linux/socket.h>
#include <linux/random.h>
mm: remove include/linux/bootmem.h Move remaining definitions and declarations from include/linux/bootmem.h into include/linux/memblock.h and remove the redundant header. The includes were replaced with the semantic patch below and then semi-automated removal of duplicated '#include <linux/memblock.h> @@ @@ - #include <linux/bootmem.h> + #include <linux/memblock.h> [sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h] Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au [sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h] Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au [sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal] Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Jonas Bonn <jonas@southpole.se> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Serge Semin <fancer.lancer@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-30 22:09:49 +00:00
#include <linux/memblock.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/time.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <linux/errqueue.h>
#include <linux/static_key.h>
#include <net/icmp.h>
#include <net/inet_common.h>
#include <net/tcp.h>
#include <net/xfrm.h>
#include <net/ip.h>
#include <net/sock.h>
#include <linux/uaccess.h>
#include <asm/ioctls.h>
#include <net/busy_poll.h>
struct percpu_counter tcp_orphan_count;
EXPORT_SYMBOL_GPL(tcp_orphan_count);
long sysctl_tcp_mem[3] __read_mostly;
EXPORT_SYMBOL(sysctl_tcp_mem);
atomic_long_t tcp_memory_allocated; /* Current allocated memory. */
EXPORT_SYMBOL(tcp_memory_allocated);
#if IS_ENABLED(CONFIG_SMC)
DEFINE_STATIC_KEY_FALSE(tcp_have_smc);
EXPORT_SYMBOL(tcp_have_smc);
#endif
/*
* Current number of TCP sockets.
*/
struct percpu_counter tcp_sockets_allocated;
EXPORT_SYMBOL(tcp_sockets_allocated);
/*
* TCP splice context
*/
struct tcp_splice_state {
struct pipe_inode_info *pipe;
size_t len;
unsigned int flags;
};
/*
* Pressure flag: try to collapse.
* Technical note: it is used by multiple contexts non atomically.
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 08:11:19 +00:00
* All the __sk_mem_schedule() is of this nature: accounting
* is strict, actions are advisory and have some latency.
*/
unsigned long tcp_memory_pressure __read_mostly;
EXPORT_SYMBOL_GPL(tcp_memory_pressure);
void tcp_enter_memory_pressure(struct sock *sk)
{
unsigned long val;
if (tcp_memory_pressure)
return;
val = jiffies;
if (!val)
val--;
if (!cmpxchg(&tcp_memory_pressure, 0, val))
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
}
EXPORT_SYMBOL_GPL(tcp_enter_memory_pressure);
void tcp_leave_memory_pressure(struct sock *sk)
{
unsigned long val;
if (!tcp_memory_pressure)
return;
val = xchg(&tcp_memory_pressure, 0);
if (val)
NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURESCHRONO,
jiffies_to_msecs(jiffies - val));
}
EXPORT_SYMBOL_GPL(tcp_leave_memory_pressure);
/* Convert seconds to retransmits based on initial and max timeout */
static u8 secs_to_retrans(int seconds, int timeout, int rto_max)
{
u8 res = 0;
if (seconds > 0) {
int period = timeout;
res = 1;
while (seconds > period && res < 255) {
res++;
timeout <<= 1;
if (timeout > rto_max)
timeout = rto_max;
period += timeout;
}
}
return res;
}
/* Convert retransmits to seconds based on initial and max timeout */
static int retrans_to_secs(u8 retrans, int timeout, int rto_max)
{
int period = 0;
if (retrans > 0) {
period = timeout;
while (--retrans) {
timeout <<= 1;
if (timeout > rto_max)
timeout = rto_max;
period += timeout;
}
}
return period;
}
static u64 tcp_compute_delivery_rate(const struct tcp_sock *tp)
{
u32 rate = READ_ONCE(tp->rate_delivered);
u32 intv = READ_ONCE(tp->rate_interval_us);
u64 rate64 = 0;
if (rate && intv) {
rate64 = (u64)rate * tp->mss_cache * USEC_PER_SEC;
do_div(rate64, intv);
}
return rate64;
}
/* Address-family independent initialization for a tcp_sock.
*
* NOTE: A lot of things set to zero explicitly by call to
* sk_alloc() so need not be done here.
*/
void tcp_init_sock(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
2016-09-07 21:49:28 +00:00
tp->out_of_order_queue = RB_ROOT;
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 05:21:27 +00:00
sk->tcp_rtx_queue = RB_ROOT;
tcp_init_xmit_timers(sk);
tcp: TCP Small Queues This introduce TSQ (TCP Small Queues) TSQ goal is to reduce number of TCP packets in xmit queues (qdisc & device queues), to reduce RTT and cwnd bias, part of the bufferbloat problem. sk->sk_wmem_alloc not allowed to grow above a given limit, allowing no more than ~128KB [1] per tcp socket in qdisc/dev layers at a given time. TSO packets are sized/capped to half the limit, so that we have two TSO packets in flight, allowing better bandwidth use. As a side effect, setting the limit to 40000 automatically reduces the standard gso max limit (65536) to 40000/2 : It can help to reduce latencies of high prio packets, having smaller TSO packets. This means we divert sock_wfree() to a tcp_wfree() handler, to queue/send following frames when skb_orphan() [2] is called for the already queued skbs. Results on my dev machines (tg3/ixgbe nics) are really impressive, using standard pfifo_fast, and with or without TSO/GSO. Without reduction of nominal bandwidth, we have reduction of buffering per bulk sender : < 1ms on Gbit (instead of 50ms with TSO) < 8ms on 100Mbit (instead of 132 ms) I no longer have 4 MBytes backlogged in qdisc by a single netperf session, and both side socket autotuning no longer use 4 Mbytes. As skb destructor cannot restart xmit itself ( as qdisc lock might be taken at this point ), we delegate the work to a tasklet. We use one tasklest per cpu for performance reasons. If tasklet finds a socket owned by the user, it sets TSQ_OWNED flag. This flag is tested in a new protocol method called from release_sock(), to eventually send new segments. [1] New /proc/sys/net/ipv4/tcp_limit_output_bytes tunable [2] skb_orphan() is usually called at TX completion time, but some drivers call it in their start_xmit() handler. These drivers should at least use BQL, or else a single TCP session can still fill the whole NIC TX ring, since TSQ will have no effect. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Dave Taht <dave.taht@bufferbloat.net> Cc: Tom Herbert <therbert@google.com> Cc: Matt Mathis <mattmathis@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-11 05:50:31 +00:00
INIT_LIST_HEAD(&tp->tsq_node);
tcp: new list for sent but unacked skbs for RACK recovery This patch adds a new queue (list) that tracks the sent but not yet acked or SACKed skbs for a TCP connection. The list is chronologically ordered by skb->skb_mstamp (the head is the oldest sent skb). This list will be used to optimize TCP Rack recovery, which checks an skb's timestamp to judge if it has been lost and needs to be retransmitted. Since TCP write queue is ordered by sequence instead of sent time, RACK has to scan over the write queue to catch all eligible packets to detect lost retransmission, and iterates through SACKed skbs repeatedly. Special cares for rare events: 1. TCP repair fakes skb transmission so the send queue needs adjusted 2. SACK reneging would require re-inserting SACKed skbs into the send queue. For now I believe it's not worth the complexity to make RACK work perfectly on SACK reneging, so we do nothing here. 3. Fast Open: currently for non-TFO, send-queue correctly queues the pure SYN packet. For TFO which queues a pure SYN and then a data packet, send-queue only queues the data packet but not the pure SYN due to the structure of TFO code. This is okay because the SYN receiver would never respond with a SACK on a missing SYN (i.e. SYN is never fast-retransmitted by SACK/RACK). In order to not grow sk_buff, we use an union for the new list and _skb_refdst/destructor fields. This is a bit complicated because we need to make sure _skb_refdst and destructor are properly zeroed before skb is cloned/copied at transmit, and before being freed. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-04 19:59:58 +00:00
INIT_LIST_HEAD(&tp->tsorted_sent_queue);
icsk->icsk_rto = TCP_TIMEOUT_INIT;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
minmax_reset(&tp->rtt_min, tcp_jiffies32, ~0U);
/* So many TCP implementations out there (incorrectly) count the
* initial SYN frame in their delayed-ACK and congestion control
* algorithms that we must have the following bandaid to talk
* efficiently to them. -DaveM
*/
tp->snd_cwnd = TCP_INIT_CWND;
tcp: track application-limited rate samples This commit adds code to track whether the delivery rate represented by each rate_sample was limited by the application. Upon each transmit, we store in the is_app_limited field in the skb a boolean bit indicating whether there is a known "bubble in the pipe": a point in the rate sample interval where the sender was application-limited, and did not transmit even though the cwnd and pacing rate allowed it. This logic marks the flow app-limited on a write if *all* of the following are true: 1) There is less than 1 MSS of unsent data in the write queue available to transmit. 2) There is no packet in the sender's queues (e.g. in fq or the NIC tx queue). 3) The connection is not limited by cwnd. 4) There are no lost packets to retransmit. The tcp_rate_check_app_limited() code in tcp_rate.c determines whether the connection is application-limited at the moment. If the flow is application-limited, it sets the tp->app_limited field. If the flow is application-limited then that means there is effectively a "bubble" of silence in the pipe now, and this silence will be reflected in a lower bandwidth sample for any rate samples from now until we get an ACK indicating this bubble has exited the pipe: specifically, until we get an ACK for the next packet we transmit. When we send every skb we record in scb->tx.is_app_limited whether the resulting rate sample will be application-limited. The code in tcp_rate_gen() checks to see when it is safe to mark all known application-limited bubbles of silence as having exited the pipe. It does this by checking to see when the delivered count moves past the tp->app_limited marker. At this point it zeroes the tp->app_limited marker, as all known bubbles are out of the pipe. We make room for the tx.is_app_limited bit in the skb by borrowing a bit from the in_flight field used by NV to record the number of bytes in flight. The receive window in the TCP header is 16 bits, and the max receive window scaling shift factor is 14 (RFC 1323). So the max receive window offered by the TCP protocol is 2^(16+14) = 2^30. So we only need 30 bits for the tx.in_flight used by NV. Signed-off-by: Van Jacobson <vanj@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Nandita Dukkipati <nanditad@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-20 03:39:15 +00:00
/* There's a bubble in the pipe until at least the first ACK. */
tp->app_limited = ~0U;
/* See draft-stevens-tcpca-spec-01 for discussion of the
* initialization of these values.
*/
tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
tp->snd_cwnd_clamp = ~0;
tp->mss_cache = TCP_MSS_DEFAULT;
tp->reordering = sock_net(sk)->ipv4.sysctl_tcp_reordering;
tcp_assign_congestion_control(sk);
tp->tsoffset = 0;
tcp: higher throughput under reordering with adaptive RACK reordering wnd Currently TCP RACK loss detection does not work well if packets are being reordered beyond its static reordering window (min_rtt/4).Under such reordering it may falsely trigger loss recoveries and reduce TCP throughput significantly. This patch improves that by increasing and reducing the reordering window based on DSACK, which is now supported in major TCP implementations. It makes RACK's reo_wnd adaptive based on DSACK and no. of recoveries. - If DSACK is received, increment reo_wnd by min_rtt/4 (upper bounded by srtt), since there is possibility that spurious retransmission was due to reordering delay longer than reo_wnd. - Persist the current reo_wnd value for TCP_RACK_RECOVERY_THRESH (16) no. of successful recoveries (accounts for full DSACK-based loss recovery undo). After that, reset it to default (min_rtt/4). - At max, reo_wnd is incremented only once per rtt. So that the new DSACK on which we are reacting, is due to the spurious retx (approx) after the reo_wnd has been updated last time. - reo_wnd is tracked in terms of steps (of min_rtt/4), rather than absolute value to account for change in rtt. In our internal testing, we observed significant increase in throughput, in scenarios where reordering exceeds min_rtt/4 (previous static value). Signed-off-by: Priyaranjan Jha <priyarjha@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-03 23:38:48 +00:00
tp->rack.reo_wnd_steps = 1;
sk->sk_state = TCP_CLOSE;
sk->sk_write_space = sk_stream_write_space;
sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
icsk->icsk_sync_mss = tcp_sync_mss;
sk->sk_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[1];
sk->sk_rcvbuf = sock_net(sk)->ipv4.sysctl_tcp_rmem[1];
sk_sockets_allocated_inc(sk);
2018-02-19 19:56:47 +00:00
sk->sk_route_forced_caps = NETIF_F_GSO;
}
EXPORT_SYMBOL(tcp_init_sock);
tcp: uniform the set up of sockets after successful connection Currently in the TCP code, the initialization sequence for cached metrics, congestion control, BPF, etc, after successful connection is very inconsistent. This introduces inconsistent bevhavior and is prone to bugs. The current call sequence is as follows: (1) for active case (tcp_finish_connect() case): tcp_mtup_init(sk); icsk->icsk_af_ops->rebuild_header(sk); tcp_init_metrics(sk); tcp_call_bpf(sk, BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB); tcp_init_congestion_control(sk); tcp_init_buffer_space(sk); (2) for passive case (tcp_rcv_state_process() TCP_SYN_RECV case): icsk->icsk_af_ops->rebuild_header(sk); tcp_call_bpf(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB); tcp_init_congestion_control(sk); tcp_mtup_init(sk); tcp_init_buffer_space(sk); tcp_init_metrics(sk); (3) for TFO passive case (tcp_fastopen_create_child()): inet_csk(child)->icsk_af_ops->rebuild_header(child); tcp_init_congestion_control(child); tcp_mtup_init(child); tcp_init_metrics(child); tcp_call_bpf(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB); tcp_init_buffer_space(child); This commit uniforms the above functions to have the following sequence: tcp_mtup_init(sk); icsk->icsk_af_ops->rebuild_header(sk); tcp_init_metrics(sk); tcp_call_bpf(sk, BPF_SOCK_OPS_ACTIVE/PASSIVE_ESTABLISHED_CB); tcp_init_congestion_control(sk); tcp_init_buffer_space(sk); This sequence is the same as the (1) active case. We pick this sequence because this order correctly allows BPF to override the settings including congestion control module and initial cwnd, etc from the route, and then allows the CC module to see those settings. Suggested-by: Neal Cardwell <ncardwell@google.com> Tested-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-04 17:03:44 +00:00
void tcp_init_transfer(struct sock *sk, int bpf_op)
{
struct inet_connection_sock *icsk = inet_csk(sk);
tcp_mtup_init(sk);
icsk->icsk_af_ops->rebuild_header(sk);
tcp_init_metrics(sk);
tcp_call_bpf(sk, bpf_op, 0, NULL);
tcp: uniform the set up of sockets after successful connection Currently in the TCP code, the initialization sequence for cached metrics, congestion control, BPF, etc, after successful connection is very inconsistent. This introduces inconsistent bevhavior and is prone to bugs. The current call sequence is as follows: (1) for active case (tcp_finish_connect() case): tcp_mtup_init(sk); icsk->icsk_af_ops->rebuild_header(sk); tcp_init_metrics(sk); tcp_call_bpf(sk, BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB); tcp_init_congestion_control(sk); tcp_init_buffer_space(sk); (2) for passive case (tcp_rcv_state_process() TCP_SYN_RECV case): icsk->icsk_af_ops->rebuild_header(sk); tcp_call_bpf(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB); tcp_init_congestion_control(sk); tcp_mtup_init(sk); tcp_init_buffer_space(sk); tcp_init_metrics(sk); (3) for TFO passive case (tcp_fastopen_create_child()): inet_csk(child)->icsk_af_ops->rebuild_header(child); tcp_init_congestion_control(child); tcp_mtup_init(child); tcp_init_metrics(child); tcp_call_bpf(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB); tcp_init_buffer_space(child); This commit uniforms the above functions to have the following sequence: tcp_mtup_init(sk); icsk->icsk_af_ops->rebuild_header(sk); tcp_init_metrics(sk); tcp_call_bpf(sk, BPF_SOCK_OPS_ACTIVE/PASSIVE_ESTABLISHED_CB); tcp_init_congestion_control(sk); tcp_init_buffer_space(sk); This sequence is the same as the (1) active case. We pick this sequence because this order correctly allows BPF to override the settings including congestion control module and initial cwnd, etc from the route, and then allows the CC module to see those settings. Suggested-by: Neal Cardwell <ncardwell@google.com> Tested-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-04 17:03:44 +00:00
tcp_init_congestion_control(sk);
tcp_init_buffer_space(sk);
}
static void tcp_tx_timestamp(struct sock *sk, u16 tsflags)
net-timestamp: TCP timestamping TCP timestamping extends SO_TIMESTAMPING to bytestreams. Bytestreams do not have a 1:1 relationship between send() buffers and network packets. The feature interprets a send call on a bytestream as a request for a timestamp for the last byte in that send() buffer. The choice corresponds to a request for a timestamp when all bytes in the buffer have been sent. That assumption depends on in-order kernel transmission. This is the common case. That said, it is possible to construct a traffic shaping tree that would result in reordering. The guarantee is strong, then, but not ironclad. This implementation supports send and sendpages (splice). GSO replaces one large packet with multiple smaller packets. This patch also copies the option into the correct smaller packet. This patch does not yet support timestamping on data in an initial TCP Fast Open SYN, because that takes a very different data path. If ID generation in ee_data is enabled, bytestream timestamps return a byte offset, instead of the packet counter for datagrams. The implementation supports a single timestamp per packet. It silenty replaces requests for previous timestamps. To avoid missing tstamps, flush the tcp queue by disabling Nagle, cork and autocork. Missing tstamps can be detected by offset when the ee_data ID is enabled. Implementation details: - On GSO, the timestamping code can be included in the main loop. I moved it into its own loop to reduce the impact on the common case to a single branch. - To avoid leaking the absolute seqno to userspace, the offset returned in ee_data must always be relative. It is an offset between an skb and sk field. The first is always set (also for GSO & ACK). The second must also never be uninitialized. Only allow the ID option on sockets in the ESTABLISHED state, for which the seqno is available. Never reset it to zero (instead, move it to the current seqno when reenabling the option). Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 02:11:49 +00:00
{
struct sk_buff *skb = tcp_write_queue_tail(sk);
if (tsflags && skb) {
struct skb_shared_info *shinfo = skb_shinfo(skb);
struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
net-timestamp: TCP timestamping TCP timestamping extends SO_TIMESTAMPING to bytestreams. Bytestreams do not have a 1:1 relationship between send() buffers and network packets. The feature interprets a send call on a bytestream as a request for a timestamp for the last byte in that send() buffer. The choice corresponds to a request for a timestamp when all bytes in the buffer have been sent. That assumption depends on in-order kernel transmission. This is the common case. That said, it is possible to construct a traffic shaping tree that would result in reordering. The guarantee is strong, then, but not ironclad. This implementation supports send and sendpages (splice). GSO replaces one large packet with multiple smaller packets. This patch also copies the option into the correct smaller packet. This patch does not yet support timestamping on data in an initial TCP Fast Open SYN, because that takes a very different data path. If ID generation in ee_data is enabled, bytestream timestamps return a byte offset, instead of the packet counter for datagrams. The implementation supports a single timestamp per packet. It silenty replaces requests for previous timestamps. To avoid missing tstamps, flush the tcp queue by disabling Nagle, cork and autocork. Missing tstamps can be detected by offset when the ee_data ID is enabled. Implementation details: - On GSO, the timestamping code can be included in the main loop. I moved it into its own loop to reduce the impact on the common case to a single branch. - To avoid leaking the absolute seqno to userspace, the offset returned in ee_data must always be relative. It is an offset between an skb and sk field. The first is always set (also for GSO & ACK). The second must also never be uninitialized. Only allow the ID option on sockets in the ESTABLISHED state, for which the seqno is available. Never reset it to zero (instead, move it to the current seqno when reenabling the option). Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 02:11:49 +00:00
sock_tx_timestamp(sk, tsflags, &shinfo->tx_flags);
if (tsflags & SOF_TIMESTAMPING_TX_ACK)
tcb->txstamp_ack = 1;
if (tsflags & SOF_TIMESTAMPING_TX_RECORD_MASK)
shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
}
net-timestamp: TCP timestamping TCP timestamping extends SO_TIMESTAMPING to bytestreams. Bytestreams do not have a 1:1 relationship between send() buffers and network packets. The feature interprets a send call on a bytestream as a request for a timestamp for the last byte in that send() buffer. The choice corresponds to a request for a timestamp when all bytes in the buffer have been sent. That assumption depends on in-order kernel transmission. This is the common case. That said, it is possible to construct a traffic shaping tree that would result in reordering. The guarantee is strong, then, but not ironclad. This implementation supports send and sendpages (splice). GSO replaces one large packet with multiple smaller packets. This patch also copies the option into the correct smaller packet. This patch does not yet support timestamping on data in an initial TCP Fast Open SYN, because that takes a very different data path. If ID generation in ee_data is enabled, bytestream timestamps return a byte offset, instead of the packet counter for datagrams. The implementation supports a single timestamp per packet. It silenty replaces requests for previous timestamps. To avoid missing tstamps, flush the tcp queue by disabling Nagle, cork and autocork. Missing tstamps can be detected by offset when the ee_data ID is enabled. Implementation details: - On GSO, the timestamping code can be included in the main loop. I moved it into its own loop to reduce the impact on the common case to a single branch. - To avoid leaking the absolute seqno to userspace, the offset returned in ee_data must always be relative. It is an offset between an skb and sk field. The first is always set (also for GSO & ACK). The second must also never be uninitialized. Only allow the ID option on sockets in the ESTABLISHED state, for which the seqno is available. Never reset it to zero (instead, move it to the current seqno when reenabling the option). Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 02:11:49 +00:00
}
static inline bool tcp_stream_is_readable(const struct tcp_sock *tp,
int target, struct sock *sk)
{
return (tp->rcv_nxt - tp->copied_seq >= target) ||
(sk->sk_prot->stream_memory_read ?
sk->sk_prot->stream_memory_read(sk) : false);
}
/*
* Wait for a TCP event.
*
* Note that we don't need to lock the socket, as the upper poll layers
* take care of normal races (between the test and the event) and we don't
* go look at any of the socket buffers directly.
*/
__poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
__poll_t mask;
struct sock *sk = sock->sk;
const struct tcp_sock *tp = tcp_sk(sk);
int state;
sock_poll_wait(file, sock, wait);
state = inet_sk_state_load(sk);
if (state == TCP_LISTEN)
return inet_csk_listen_poll(sk);
/* Socket is not locked. We are protected from async events
* by poll logic and correct handling of state changes
* made by other threads is impossible in any case.
*/
mask = 0;
/*
* EPOLLHUP is certainly not done right. But poll() doesn't
* have a notion of HUP in just one direction, and for a
* socket the read side is more interesting.
*
* Some poll() documentation says that EPOLLHUP is incompatible
* with the EPOLLOUT/POLLWR flags, so somebody should check this
* all. But careful, it tends to be safer to return too many
* bits than too few, and you can easily break real applications
* if you don't tell them that something has hung up!
*
* Check-me.
*
* Check number 1. EPOLLHUP is _UNMASKABLE_ event (see UNIX98 and
* our fs/select.c). It means that after we received EOF,
* poll always returns immediately, making impossible poll() on write()
* in state CLOSE_WAIT. One solution is evident --- to set EPOLLHUP
* if and only if shutdown has been made in both directions.
* Actually, it is interesting to look how Solaris and DUX
* solve this dilemma. I would prefer, if EPOLLHUP were maskable,
* then we could set it on SND_SHUTDOWN. BTW examples given
* in Stevens' books assume exactly this behaviour, it explains
* why EPOLLHUP is incompatible with EPOLLOUT. --ANK
*
* NOTE. Check for TCP_CLOSE is added. The goal is to prevent
* blocking on fresh not-connected or disconnected socket. --ANK
*/
if (sk->sk_shutdown == SHUTDOWN_MASK || state == TCP_CLOSE)
mask |= EPOLLHUP;
if (sk->sk_shutdown & RCV_SHUTDOWN)
mask |= EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
/* Connected or passive Fast Open socket? */
if (state != TCP_SYN_SENT &&
(state != TCP_SYN_RECV || tp->fastopen_rsk)) {
int target = sock_rcvlowat(sk, 0, INT_MAX);
if (tp->urg_seq == tp->copied_seq &&
!sock_flag(sk, SOCK_URGINLINE) &&
tp->urg_data)
target++;
if (tcp_stream_is_readable(tp, target, sk))
mask |= EPOLLIN | EPOLLRDNORM;
if (!(sk->sk_shutdown & SEND_SHUTDOWN)) {
if (sk_stream_is_writeable(sk)) {
mask |= EPOLLOUT | EPOLLWRNORM;
} else { /* send SIGIO later */
sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
/* Race breaker. If space is freed after
* wspace test but before the flags are set,
* IO signal will be lost. Memory barrier
* pairs with the input side.
*/
smp_mb__after_atomic();
if (sk_stream_is_writeable(sk))
mask |= EPOLLOUT | EPOLLWRNORM;
}
2010-08-24 16:05:48 +00:00
} else
mask |= EPOLLOUT | EPOLLWRNORM;
if (tp->urg_data & TCP_URG_VALID)
mask |= EPOLLPRI;
} else if (state == TCP_SYN_SENT && inet_sk(sk)->defer_connect) {
net/tcp-fastopen: Add new API support This patch adds a new socket option, TCP_FASTOPEN_CONNECT, as an alternative way to perform Fast Open on the active side (client). Prior to this patch, a client needs to replace the connect() call with sendto(MSG_FASTOPEN). This can be cumbersome for applications who want to use Fast Open: these socket operations are often done in lower layer libraries used by many other applications. Changing these libraries and/or the socket call sequences are not trivial. A more convenient approach is to perform Fast Open by simply enabling a socket option when the socket is created w/o changing other socket calls sequence: s = socket() create a new socket setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT …); newly introduced sockopt If set, new functionality described below will be used. Return ENOTSUPP if TFO is not supported or not enabled in the kernel. connect() With cookie present, return 0 immediately. With no cookie, initiate 3WHS with TFO cookie-request option and return -1 with errno = EINPROGRESS. write()/sendmsg() With cookie present, send out SYN with data and return the number of bytes buffered. With no cookie, and 3WHS not yet completed, return -1 with errno = EINPROGRESS. No MSG_FASTOPEN flag is needed. read() Return -1 with errno = EWOULDBLOCK/EAGAIN if connect() is called but write() is not called yet. Return -1 with errno = EWOULDBLOCK/EAGAIN if connection is established but no msg is received yet. Return number of bytes read if socket is established and there is msg received. The new API simplifies life for applications that always perform a write() immediately after a successful connect(). Such applications can now take advantage of Fast Open by merely making one new setsockopt() call at the time of creating the socket. Nothing else about the application's socket call sequence needs to change. Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-23 18:59:22 +00:00
/* Active TCP fastopen socket with defer_connect
* Return EPOLLOUT so application can call write()
net/tcp-fastopen: Add new API support This patch adds a new socket option, TCP_FASTOPEN_CONNECT, as an alternative way to perform Fast Open on the active side (client). Prior to this patch, a client needs to replace the connect() call with sendto(MSG_FASTOPEN). This can be cumbersome for applications who want to use Fast Open: these socket operations are often done in lower layer libraries used by many other applications. Changing these libraries and/or the socket call sequences are not trivial. A more convenient approach is to perform Fast Open by simply enabling a socket option when the socket is created w/o changing other socket calls sequence: s = socket() create a new socket setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT …); newly introduced sockopt If set, new functionality described below will be used. Return ENOTSUPP if TFO is not supported or not enabled in the kernel. connect() With cookie present, return 0 immediately. With no cookie, initiate 3WHS with TFO cookie-request option and return -1 with errno = EINPROGRESS. write()/sendmsg() With cookie present, send out SYN with data and return the number of bytes buffered. With no cookie, and 3WHS not yet completed, return -1 with errno = EINPROGRESS. No MSG_FASTOPEN flag is needed. read() Return -1 with errno = EWOULDBLOCK/EAGAIN if connect() is called but write() is not called yet. Return -1 with errno = EWOULDBLOCK/EAGAIN if connection is established but no msg is received yet. Return number of bytes read if socket is established and there is msg received. The new API simplifies life for applications that always perform a write() immediately after a successful connect(). Such applications can now take advantage of Fast Open by merely making one new setsockopt() call at the time of creating the socket. Nothing else about the application's socket call sequence needs to change. Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-23 18:59:22 +00:00
* in order for kernel to generate SYN+data
*/
mask |= EPOLLOUT | EPOLLWRNORM;
}
/* This barrier is coupled with smp_wmb() in tcp_reset() */
smp_rmb();
net-timestamp: TCP timestamping TCP timestamping extends SO_TIMESTAMPING to bytestreams. Bytestreams do not have a 1:1 relationship between send() buffers and network packets. The feature interprets a send call on a bytestream as a request for a timestamp for the last byte in that send() buffer. The choice corresponds to a request for a timestamp when all bytes in the buffer have been sent. That assumption depends on in-order kernel transmission. This is the common case. That said, it is possible to construct a traffic shaping tree that would result in reordering. The guarantee is strong, then, but not ironclad. This implementation supports send and sendpages (splice). GSO replaces one large packet with multiple smaller packets. This patch also copies the option into the correct smaller packet. This patch does not yet support timestamping on data in an initial TCP Fast Open SYN, because that takes a very different data path. If ID generation in ee_data is enabled, bytestream timestamps return a byte offset, instead of the packet counter for datagrams. The implementation supports a single timestamp per packet. It silenty replaces requests for previous timestamps. To avoid missing tstamps, flush the tcp queue by disabling Nagle, cork and autocork. Missing tstamps can be detected by offset when the ee_data ID is enabled. Implementation details: - On GSO, the timestamping code can be included in the main loop. I moved it into its own loop to reduce the impact on the common case to a single branch. - To avoid leaking the absolute seqno to userspace, the offset returned in ee_data must always be relative. It is an offset between an skb and sk field. The first is always set (also for GSO & ACK). The second must also never be uninitialized. Only allow the ID option on sockets in the ESTABLISHED state, for which the seqno is available. Never reset it to zero (instead, move it to the current seqno when reenabling the option). Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 02:11:49 +00:00
if (sk->sk_err || !skb_queue_empty(&sk->sk_error_queue))
mask |= EPOLLERR;
return mask;
}
EXPORT_SYMBOL(tcp_poll);
int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
struct tcp_sock *tp = tcp_sk(sk);
int answ;
bool slow;
switch (cmd) {
case SIOCINQ:
if (sk->sk_state == TCP_LISTEN)
return -EINVAL;
slow = lock_sock_fast(sk);
answ = tcp_inq(sk);
unlock_sock_fast(sk, slow);
break;
case SIOCATMARK:
answ = tp->urg_data && tp->urg_seq == tp->copied_seq;
break;
case SIOCOUTQ:
if (sk->sk_state == TCP_LISTEN)
return -EINVAL;
if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
answ = 0;
else
answ = tp->write_seq - tp->snd_una;
break;
case SIOCOUTQNSD:
if (sk->sk_state == TCP_LISTEN)
return -EINVAL;
if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
answ = 0;
else
answ = tp->write_seq - tp->snd_nxt;
break;
default:
return -ENOIOCTLCMD;
}
return put_user(answ, (int __user *)arg);
}
EXPORT_SYMBOL(tcp_ioctl);
static inline void tcp_mark_push(struct tcp_sock *tp, struct sk_buff *skb)
{
TCP_SKB_CB(skb)->tcp_flags |= TCPHDR_PSH;
tp->pushed_seq = tp->write_seq;
}
static inline bool forced_push(const struct tcp_sock *tp)
{
return after(tp->write_seq, tp->pushed_seq + (tp->max_window >> 1));
}
static void skb_entail(struct sock *sk, struct sk_buff *skb)
{
[TCP]: Sed magic converts func(sk, tp, ...) -> func(sk, ...) This is (mostly) automated change using magic: sed -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e 's|struct sock \*sk,[\n\t ]*struct tcp_sock \*tp\([^{]*\n{\n\)| struct sock \*sk\1\tstruct tcp_sock *tp = tcp_sk(sk);\n|g' -e 's|struct sock \*sk, struct tcp_sock \*tp| struct sock \*sk|g' -e 's|sk, tp\([^-]\)|sk\1|g' Fixed four unused variable (tp) warnings that were introduced. In addition, manually added newlines after local variables and tweaked function arguments positioning. $ gcc --version gcc (GCC) 4.1.1 20060525 (Red Hat 4.1.1-1) ... $ codiff -fV built-in.o.old built-in.o.new net/ipv4/route.c: rt_cache_flush | +14 1 function changed, 14 bytes added net/ipv4/tcp.c: tcp_setsockopt | -5 tcp_sendpage | -25 tcp_sendmsg | -16 3 functions changed, 46 bytes removed net/ipv4/tcp_input.c: tcp_try_undo_recovery | +3 tcp_try_undo_dsack | +2 tcp_mark_head_lost | -12 tcp_ack | -15 tcp_event_data_recv | -32 tcp_rcv_state_process | -10 tcp_rcv_established | +1 7 functions changed, 6 bytes added, 69 bytes removed, diff: -63 net/ipv4/tcp_output.c: update_send_head | -9 tcp_transmit_skb | +19 tcp_cwnd_validate | +1 tcp_write_wakeup | -17 __tcp_push_pending_frames | -25 tcp_push_one | -8 tcp_send_fin | -4 7 functions changed, 20 bytes added, 63 bytes removed, diff: -43 built-in.o.new: 18 functions changed, 40 bytes added, 178 bytes removed, diff: -138 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-21 05:18:02 +00:00
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
skb->csum = 0;
tcb->seq = tcb->end_seq = tp->write_seq;
tcb->tcp_flags = TCPHDR_ACK;
tcb->sacked = 0;
__skb_header_release(skb);
tcp_add_write_queue_tail(sk, skb);
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 08:11:19 +00:00
sk->sk_wmem_queued += skb->truesize;
sk_mem_charge(sk, skb->truesize);
if (tp->nonagle & TCP_NAGLE_PUSH)
tp->nonagle &= ~TCP_NAGLE_PUSH;
tcp: fix slow start after idle vs TSO/GSO slow start after idle might reduce cwnd, but we perform this after first packet was cooked and sent. With TSO/GSO, it means that we might send a full TSO packet even if cwnd should have been reduced to IW10. Moving the SSAI check in skb_entail() makes sense, because we slightly reduce number of times this check is done, especially for large send() and TCP Small queue callbacks from softirq context. As Neal pointed out, we also need to perform the check if/when receive window opens. Tested: Following packetdrill test demonstrates the problem // Test of slow start after idle `sysctl -q net.ipv4.tcp_slow_start_after_idle=1` 0.000 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 +0 < S 0:0(0) win 65535 <mss 1000,sackOK,nop,nop,nop,wscale 7> +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 6> +.100 < . 1:1(0) ack 1 win 511 +0 accept(3, ..., ...) = 4 +0 setsockopt(4, SOL_SOCKET, SO_SNDBUF, [200000], 4) = 0 +0 write(4, ..., 26000) = 26000 +0 > . 1:5001(5000) ack 1 +0 > . 5001:10001(5000) ack 1 +0 %{ assert tcpi_snd_cwnd == 10 }% +.100 < . 1:1(0) ack 10001 win 511 +0 %{ assert tcpi_snd_cwnd == 20, tcpi_snd_cwnd }% +0 > . 10001:20001(10000) ack 1 +0 > P. 20001:26001(6000) ack 1 +.100 < . 1:1(0) ack 26001 win 511 +0 %{ assert tcpi_snd_cwnd == 36, tcpi_snd_cwnd }% +4 write(4, ..., 20000) = 20000 // If slow start after idle works properly, we should send 5 MSS here (cwnd/2) +0 > . 26001:31001(5000) ack 1 +0 %{ assert tcpi_snd_cwnd == 10, tcpi_snd_cwnd }% +0 > . 31001:36001(5000) ack 1 Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-21 19:30:00 +00:00
tcp_slow_start_after_idle_check(sk);
}
static inline void tcp_mark_urg(struct tcp_sock *tp, int flags)
{
if (flags & MSG_OOB)
tp->snd_up = tp->write_seq;
}
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
/* If a not yet filled skb is pushed, do not send it if
* we have data packets in Qdisc or NIC queues :
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
* Because TX completion will happen shortly, it gives a chance
* to coalesce future sendmsg() payload into this skb, without
* need for a timer, and with no latency trade off.
* As packets containing data payload have a bigger truesize
* than pure acks (dataless) packets, the last checks prevent
* autocorking if we only have an ACK in Qdisc/NIC queues,
* or if TX completion was delayed after we processed ACK packet.
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
*/
static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
int size_goal)
{
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
return skb->len < size_goal &&
sock_net(sk)->ipv4.sysctl_tcp_autocorking &&
tcp: restore autocorking When adding rb-tree for TCP retransmit queue, we inadvertently broke TCP autocorking. tcp_should_autocork() should really check if the rtx queue is not empty. Tested: Before the fix : $ nstat -n;./netperf -H 10.246.7.152 -Cc -- -m 500;nstat | grep AutoCork MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.246.7.152 () port 0 AF_INET Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 540000 262144 500 10.00 2682.85 2.47 1.59 3.618 2.329 TcpExtTCPAutoCorking 33 0.0 // Same test, but forcing TCP_NODELAY $ nstat -n;./netperf -H 10.246.7.152 -Cc -- -D -m 500;nstat | grep AutoCork MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.246.7.152 () port 0 AF_INET : nodelay Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 540000 262144 500 10.00 1408.75 2.44 2.96 6.802 8.259 TcpExtTCPAutoCorking 1 0.0 After the fix : $ nstat -n;./netperf -H 10.246.7.152 -Cc -- -m 500;nstat | grep AutoCork MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.246.7.152 () port 0 AF_INET Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 540000 262144 500 10.00 5472.46 2.45 1.43 1.761 1.027 TcpExtTCPAutoCorking 361293 0.0 // With TCP_NODELAY option $ nstat -n;./netperf -H 10.246.7.152 -Cc -- -D -m 500;nstat | grep AutoCork MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.246.7.152 () port 0 AF_INET : nodelay Recv Send Send Utilization Service Demand Socket Socket Message Elapsed Send Recv Send Recv Size Size Size Time Throughput local remote local remote bytes bytes bytes secs. 10^6bits/s % S % S us/KB us/KB 540000 262144 500 10.00 5454.96 2.46 1.63 1.775 1.174 TcpExtTCPAutoCorking 315448 0.0 Fixes: 75c119afe14f ("tcp: implement rb-tree based retransmit queue") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Michael Wenig <mwenig@vmware.com> Tested-by: Michael Wenig <mwenig@vmware.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Michael Wenig <mwenig@vmware.com> Tested-by: Michael Wenig <mwenig@vmware.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-03 03:25:13 +00:00
!tcp_rtx_queue_empty(sk) &&
refcount_read(&sk->sk_wmem_alloc) > skb->truesize;
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
}
static void tcp_push(struct sock *sk, int flags, int mss_now,
int nonagle, int size_goal)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
skb = tcp_write_queue_tail(sk);
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 05:21:27 +00:00
if (!skb)
return;
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
if (!(flags & MSG_MORE) || forced_push(tp))
tcp_mark_push(tp, skb);
tcp_mark_urg(tp, flags);
if (tcp_should_autocork(sk, skb, size_goal)) {
/* avoid atomic op if TSQ_THROTTLED bit is already set */
if (!test_bit(TSQ_THROTTLED, &sk->sk_tsq_flags)) {
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAUTOCORKING);
set_bit(TSQ_THROTTLED, &sk->sk_tsq_flags);
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
}
/* It is possible TX completion already happened
* before we set TSQ_THROTTLED.
*/
if (refcount_read(&sk->sk_wmem_alloc) > skb->truesize)
return;
}
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
if (flags & MSG_MORE)
nonagle = TCP_NAGLE_CORK;
__tcp_push_pending_frames(sk, mss_now, nonagle);
}
static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
unsigned int offset, size_t len)
{
struct tcp_splice_state *tss = rd_desc->arg.data;
int ret;
ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
min(rd_desc->count, len), tss->flags);
if (ret > 0)
rd_desc->count -= ret;
return ret;
}
static int __tcp_splice_read(struct sock *sk, struct tcp_splice_state *tss)
{
/* Store TCP splice context information in read_descriptor_t. */
read_descriptor_t rd_desc = {
.arg.data = tss,
.count = tss->len,
};
return tcp_read_sock(sk, &rd_desc, tcp_splice_data_recv);
}
/**
* tcp_splice_read - splice data from TCP socket to a pipe
* @sock: socket to splice from
* @ppos: position (not valid)
* @pipe: pipe to splice to
* @len: number of bytes to splice
* @flags: splice modifier flags
*
* Description:
* Will read pages from given socket and fill them into a pipe.
*
**/
ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
struct sock *sk = sock->sk;
struct tcp_splice_state tss = {
.pipe = pipe,
.len = len,
.flags = flags,
};
long timeo;
ssize_t spliced;
int ret;
sock_rps_record_flow(sk);
/*
* We can't seek on a socket input
*/
if (unlikely(*ppos))
return -ESPIPE;
ret = spliced = 0;
lock_sock(sk);
net: splice() from tcp to pipe should take into account O_NONBLOCK tcp_splice_read() doesnt take into account socket's O_NONBLOCK flag Before this patch : splice(socket,0,pipe,0,128*1024,SPLICE_F_MOVE); causes a random endless block (if pipe is full) and splice(socket,0,pipe,0,128*1024,SPLICE_F_MOVE | SPLICE_F_NONBLOCK); will return 0 immediately if the TCP buffer is empty. User application has no way to instruct splice() that socket should be in blocking mode but pipe in nonblock more. Many projects cannot use splice(tcp -> pipe) because of this flaw. http://git.samba.org/?p=samba.git;a=history;f=source3/lib/recvfile.c;h=ea0159642137390a0f7e57a123684e6e63e47581;hb=HEAD http://lkml.indiana.edu/hypermail/linux/kernel/0807.2/0687.html Linus introduced SPLICE_F_NONBLOCK in commit 29e350944fdc2dfca102500790d8ad6d6ff4f69d (splice: add SPLICE_F_NONBLOCK flag ) It doesn't make the splice itself necessarily nonblocking (because the actual file descriptors that are spliced from/to may block unless they have the O_NONBLOCK flag set), but it makes the splice pipe operations nonblocking. Linus intention was clear : let SPLICE_F_NONBLOCK control the splice pipe mode only This patch instruct tcp_splice_read() to use the underlying file O_NONBLOCK flag, as other socket operations do. Users will then call : splice(socket,0,pipe,0,128*1024,SPLICE_F_MOVE | SPLICE_F_NONBLOCK ); to block on data coming from socket (if file is in blocking mode), and not block on pipe output (to avoid deadlock) First version of this patch was submitted by Octavian Purdila Reported-by: Volker Lendecke <vl@samba.org> Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Octavian Purdila <opurdila@ixiacom.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-10-01 22:26:00 +00:00
timeo = sock_rcvtimeo(sk, sock->file->f_flags & O_NONBLOCK);
while (tss.len) {
ret = __tcp_splice_read(sk, &tss);
if (ret < 0)
break;
else if (!ret) {
if (spliced)
break;
if (sock_flag(sk, SOCK_DONE))
break;
if (sk->sk_err) {
ret = sock_error(sk);
break;
}
if (sk->sk_shutdown & RCV_SHUTDOWN)
break;
if (sk->sk_state == TCP_CLOSE) {
/*
* This occurs when user tries to read
* from never connected socket.
*/
ret = -ENOTCONN;
break;
}
if (!timeo) {
ret = -EAGAIN;
break;
}
/* if __tcp_splice_read() got nothing while we have
* an skb in receive queue, we do not want to loop.
* This might happen with URG data.
*/
if (!skb_queue_empty(&sk->sk_receive_queue))
break;
sk_wait_data(sk, &timeo, NULL);
if (signal_pending(current)) {
ret = sock_intr_errno(timeo);
break;
}
continue;
}
tss.len -= ret;
spliced += ret;
if (!timeo)
break;
release_sock(sk);
lock_sock(sk);
if (sk->sk_err || sk->sk_state == TCP_CLOSE ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
signal_pending(current))
break;
}
release_sock(sk);
if (spliced)
return spliced;
return ret;
}
EXPORT_SYMBOL(tcp_splice_read);
struct sk_buff *sk_stream_alloc_skb(struct sock *sk, int size, gfp_t gfp,
bool force_schedule)
{
struct sk_buff *skb;
/* The TCP header must be at least 32-bit aligned. */
size = ALIGN(size, 4);
if (unlikely(tcp_under_memory_pressure(sk)))
sk_mem_reclaim_partial(sk);
skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp);
if (likely(skb)) {
bool mem_scheduled;
if (force_schedule) {
mem_scheduled = true;
sk_forced_mem_schedule(sk, skb->truesize);
} else {
mem_scheduled = sk_wmem_schedule(sk, skb->truesize);
}
if (likely(mem_scheduled)) {
skb_reserve(skb, sk->sk_prot->max_header);
/*
* Make sure that we have exactly size bytes
* available to the caller, no more, no less.
*/
skb->reserved_tailroom = skb->end - skb->tail - size;
tcp: new list for sent but unacked skbs for RACK recovery This patch adds a new queue (list) that tracks the sent but not yet acked or SACKed skbs for a TCP connection. The list is chronologically ordered by skb->skb_mstamp (the head is the oldest sent skb). This list will be used to optimize TCP Rack recovery, which checks an skb's timestamp to judge if it has been lost and needs to be retransmitted. Since TCP write queue is ordered by sequence instead of sent time, RACK has to scan over the write queue to catch all eligible packets to detect lost retransmission, and iterates through SACKed skbs repeatedly. Special cares for rare events: 1. TCP repair fakes skb transmission so the send queue needs adjusted 2. SACK reneging would require re-inserting SACKed skbs into the send queue. For now I believe it's not worth the complexity to make RACK work perfectly on SACK reneging, so we do nothing here. 3. Fast Open: currently for non-TFO, send-queue correctly queues the pure SYN packet. For TFO which queues a pure SYN and then a data packet, send-queue only queues the data packet but not the pure SYN due to the structure of TFO code. This is okay because the SYN receiver would never respond with a SACK on a missing SYN (i.e. SYN is never fast-retransmitted by SACK/RACK). In order to not grow sk_buff, we use an union for the new list and _skb_refdst/destructor fields. This is a bit complicated because we need to make sure _skb_refdst and destructor are properly zeroed before skb is cloned/copied at transmit, and before being freed. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-04 19:59:58 +00:00
INIT_LIST_HEAD(&skb->tcp_tsorted_anchor);
return skb;
}
__kfree_skb(skb);
} else {
sk->sk_prot->enter_memory_pressure(sk);
sk_stream_moderate_sndbuf(sk);
}
return NULL;
}
static unsigned int tcp_xmit_size_goal(struct sock *sk, u32 mss_now,
int large_allowed)
{
struct tcp_sock *tp = tcp_sk(sk);
u32 new_size_goal, size_goal;
tcp: refine TSO autosizing Commit 95bd09eb2750 ("tcp: TSO packets automatic sizing") tried to control TSO size, but did this at the wrong place (sendmsg() time) At sendmsg() time, we might have a pessimistic view of flow rate, and we end up building very small skbs (with 2 MSS per skb). This is bad because : - It sends small TSO packets even in Slow Start where rate quickly increases. - It tends to make socket write queue very big, increasing tcp_ack() processing time, but also increasing memory needs, not necessarily accounted for, as fast clones overhead is currently ignored. - Lower GRO efficiency and more ACK packets. Servers with a lot of small lived connections suffer from this. Lets instead fill skbs as much as possible (64KB of payload), but split them at xmit time, when we have a precise idea of the flow rate. skb split is actually quite efficient. Patch looks bigger than necessary, because TCP Small Queue decision now has to take place after the eventual split. As Neal suggested, introduce a new tcp_tso_autosize() helper, so that tcp_tso_should_defer() can be synchronized on same goal. Rename tp->xmit_size_goal_segs to tp->gso_segs, as this variable contains number of mss that we can put in GSO packet, and is not related to the autosizing goal anymore. Tested: 40 ms rtt link nstat >/dev/null netperf -H remote -l -2000000 -- -s 1000000 nstat | egrep "IpInReceives|IpOutRequests|TcpOutSegs|IpExtOutOctets" Before patch : Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/s 87380 2000000 2000000 0.36 44.22 IpInReceives 600 0.0 IpOutRequests 599 0.0 TcpOutSegs 1397 0.0 IpExtOutOctets 2033249 0.0 After patch : Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 2000000 2000000 0.36 44.27 IpInReceives 221 0.0 IpOutRequests 232 0.0 TcpOutSegs 1397 0.0 IpExtOutOctets 2013953 0.0 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-07 20:22:18 +00:00
if (!large_allowed)
tcp: refine TSO autosizing Commit 95bd09eb2750 ("tcp: TSO packets automatic sizing") tried to control TSO size, but did this at the wrong place (sendmsg() time) At sendmsg() time, we might have a pessimistic view of flow rate, and we end up building very small skbs (with 2 MSS per skb). This is bad because : - It sends small TSO packets even in Slow Start where rate quickly increases. - It tends to make socket write queue very big, increasing tcp_ack() processing time, but also increasing memory needs, not necessarily accounted for, as fast clones overhead is currently ignored. - Lower GRO efficiency and more ACK packets. Servers with a lot of small lived connections suffer from this. Lets instead fill skbs as much as possible (64KB of payload), but split them at xmit time, when we have a precise idea of the flow rate. skb split is actually quite efficient. Patch looks bigger than necessary, because TCP Small Queue decision now has to take place after the eventual split. As Neal suggested, introduce a new tcp_tso_autosize() helper, so that tcp_tso_should_defer() can be synchronized on same goal. Rename tp->xmit_size_goal_segs to tp->gso_segs, as this variable contains number of mss that we can put in GSO packet, and is not related to the autosizing goal anymore. Tested: 40 ms rtt link nstat >/dev/null netperf -H remote -l -2000000 -- -s 1000000 nstat | egrep "IpInReceives|IpOutRequests|TcpOutSegs|IpExtOutOctets" Before patch : Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/s 87380 2000000 2000000 0.36 44.22 IpInReceives 600 0.0 IpOutRequests 599 0.0 TcpOutSegs 1397 0.0 IpExtOutOctets 2033249 0.0 After patch : Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 2000000 2000000 0.36 44.27 IpInReceives 221 0.0 IpOutRequests 232 0.0 TcpOutSegs 1397 0.0 IpExtOutOctets 2013953 0.0 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-07 20:22:18 +00:00
return mss_now;
/* Note : tcp_tso_autosize() will eventually split this later */
new_size_goal = sk->sk_gso_max_size - 1 - MAX_TCP_HEADER;
tcp: refine TSO autosizing Commit 95bd09eb2750 ("tcp: TSO packets automatic sizing") tried to control TSO size, but did this at the wrong place (sendmsg() time) At sendmsg() time, we might have a pessimistic view of flow rate, and we end up building very small skbs (with 2 MSS per skb). This is bad because : - It sends small TSO packets even in Slow Start where rate quickly increases. - It tends to make socket write queue very big, increasing tcp_ack() processing time, but also increasing memory needs, not necessarily accounted for, as fast clones overhead is currently ignored. - Lower GRO efficiency and more ACK packets. Servers with a lot of small lived connections suffer from this. Lets instead fill skbs as much as possible (64KB of payload), but split them at xmit time, when we have a precise idea of the flow rate. skb split is actually quite efficient. Patch looks bigger than necessary, because TCP Small Queue decision now has to take place after the eventual split. As Neal suggested, introduce a new tcp_tso_autosize() helper, so that tcp_tso_should_defer() can be synchronized on same goal. Rename tp->xmit_size_goal_segs to tp->gso_segs, as this variable contains number of mss that we can put in GSO packet, and is not related to the autosizing goal anymore. Tested: 40 ms rtt link nstat >/dev/null netperf -H remote -l -2000000 -- -s 1000000 nstat | egrep "IpInReceives|IpOutRequests|TcpOutSegs|IpExtOutOctets" Before patch : Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/s 87380 2000000 2000000 0.36 44.22 IpInReceives 600 0.0 IpOutRequests 599 0.0 TcpOutSegs 1397 0.0 IpExtOutOctets 2033249 0.0 After patch : Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 2000000 2000000 0.36 44.27 IpInReceives 221 0.0 IpOutRequests 232 0.0 TcpOutSegs 1397 0.0 IpExtOutOctets 2013953 0.0 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-07 20:22:18 +00:00
new_size_goal = tcp_bound_to_half_wnd(tp, new_size_goal);
/* We try hard to avoid divides here */
size_goal = tp->gso_segs * mss_now;
if (unlikely(new_size_goal < size_goal ||
new_size_goal >= size_goal + mss_now)) {
tp->gso_segs = min_t(u16, new_size_goal / mss_now,
sk->sk_gso_max_segs);
size_goal = tp->gso_segs * mss_now;
}
tcp: refine TSO autosizing Commit 95bd09eb2750 ("tcp: TSO packets automatic sizing") tried to control TSO size, but did this at the wrong place (sendmsg() time) At sendmsg() time, we might have a pessimistic view of flow rate, and we end up building very small skbs (with 2 MSS per skb). This is bad because : - It sends small TSO packets even in Slow Start where rate quickly increases. - It tends to make socket write queue very big, increasing tcp_ack() processing time, but also increasing memory needs, not necessarily accounted for, as fast clones overhead is currently ignored. - Lower GRO efficiency and more ACK packets. Servers with a lot of small lived connections suffer from this. Lets instead fill skbs as much as possible (64KB of payload), but split them at xmit time, when we have a precise idea of the flow rate. skb split is actually quite efficient. Patch looks bigger than necessary, because TCP Small Queue decision now has to take place after the eventual split. As Neal suggested, introduce a new tcp_tso_autosize() helper, so that tcp_tso_should_defer() can be synchronized on same goal. Rename tp->xmit_size_goal_segs to tp->gso_segs, as this variable contains number of mss that we can put in GSO packet, and is not related to the autosizing goal anymore. Tested: 40 ms rtt link nstat >/dev/null netperf -H remote -l -2000000 -- -s 1000000 nstat | egrep "IpInReceives|IpOutRequests|TcpOutSegs|IpExtOutOctets" Before patch : Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/s 87380 2000000 2000000 0.36 44.22 IpInReceives 600 0.0 IpOutRequests 599 0.0 TcpOutSegs 1397 0.0 IpExtOutOctets 2033249 0.0 After patch : Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 2000000 2000000 0.36 44.27 IpInReceives 221 0.0 IpOutRequests 232 0.0 TcpOutSegs 1397 0.0 IpExtOutOctets 2013953 0.0 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-07 20:22:18 +00:00
return max(size_goal, mss_now);
}
static int tcp_send_mss(struct sock *sk, int *size_goal, int flags)
{
int mss_now;
mss_now = tcp_current_mss(sk);
*size_goal = tcp_xmit_size_goal(sk, mss_now, !(flags & MSG_OOB));
return mss_now;
}
ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset,
size_t size, int flags)
{
struct tcp_sock *tp = tcp_sk(sk);
int mss_now, size_goal;
int err;
ssize_t copied;
long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
/* Wait for a connection to finish. One exception is TCP Fast Open
* (passive side) where data is allowed to be sent before a connection
* is fully established.
*/
if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
!tcp_passive_fastopen(sk)) {
err = sk_stream_wait_connect(sk, &timeo);
if (err != 0)
goto out_err;
}
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
mss_now = tcp_send_mss(sk, &size_goal, flags);
copied = 0;
err = -EPIPE;
if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
goto out_err;
while (size > 0) {
struct sk_buff *skb = tcp_write_queue_tail(sk);
int copy, i;
bool can_coalesce;
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 05:21:27 +00:00
if (!skb || (copy = size_goal - skb->len) <= 0 ||
tcp: Make use of MSG_EOR in tcp_sendmsg This patch adds an eor bit to the TCP_SKB_CB. When MSG_EOR is passed to tcp_sendmsg, the eor bit will be set at the skb containing the last byte of the userland's msg. The eor bit will prevent data from appending to that skb in the future. The change in do_tcp_sendpages is to honor the eor set during the previous tcp_sendmsg(MSG_EOR) call. This patch handles the tcp_sendmsg case. The followup patches will handle other skb coalescing and fragment cases. One potential use case is to use MSG_EOR with SOF_TIMESTAMPING_TX_ACK to get a more accurate TCP ack timestamping on application protocol with multiple outgoing response messages (e.g. HTTP2). Packetdrill script for testing: ~~~~~~ +0 `sysctl -q -w net.ipv4.tcp_min_tso_segs=10` +0 `sysctl -q -w net.ipv4.tcp_no_metrics_save=1` +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 0.100 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,nop,wscale 7> 0.100 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7> 0.200 < . 1:1(0) ack 1 win 257 0.200 accept(3, ..., ...) = 4 +0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 0.200 write(4, ..., 14600) = 14600 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 0.200 > . 1:7301(7300) ack 1 0.200 > P. 7301:14601(7300) ack 1 0.300 < . 1:1(0) ack 14601 win 257 0.300 > P. 14601:15331(730) ack 1 0.300 > P. 15331:16061(730) ack 1 0.400 < . 1:1(0) ack 16061 win 257 0.400 close(4) = 0 0.400 > F. 16061:16061(0) ack 1 0.400 < F. 1:1(0) ack 16062 win 257 0.400 > . 16062:16062(0) ack 2 Signed-off-by: Martin KaFai Lau <kafai@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Willem de Bruijn <willemb@google.com> Cc: Yuchung Cheng <ycheng@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-25 21:44:48 +00:00
!tcp_skb_can_collapse_to(skb)) {
new_segment:
if (!sk_stream_memory_free(sk))
goto wait_for_sndbuf;
skb = sk_stream_alloc_skb(sk, 0, sk->sk_allocation,
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 05:21:27 +00:00
tcp_rtx_and_write_queues_empty(sk));
if (!skb)
goto wait_for_memory;
[TCP]: Sed magic converts func(sk, tp, ...) -> func(sk, ...) This is (mostly) automated change using magic: sed -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e 's|struct sock \*sk,[\n\t ]*struct tcp_sock \*tp\([^{]*\n{\n\)| struct sock \*sk\1\tstruct tcp_sock *tp = tcp_sk(sk);\n|g' -e 's|struct sock \*sk, struct tcp_sock \*tp| struct sock \*sk|g' -e 's|sk, tp\([^-]\)|sk\1|g' Fixed four unused variable (tp) warnings that were introduced. In addition, manually added newlines after local variables and tweaked function arguments positioning. $ gcc --version gcc (GCC) 4.1.1 20060525 (Red Hat 4.1.1-1) ... $ codiff -fV built-in.o.old built-in.o.new net/ipv4/route.c: rt_cache_flush | +14 1 function changed, 14 bytes added net/ipv4/tcp.c: tcp_setsockopt | -5 tcp_sendpage | -25 tcp_sendmsg | -16 3 functions changed, 46 bytes removed net/ipv4/tcp_input.c: tcp_try_undo_recovery | +3 tcp_try_undo_dsack | +2 tcp_mark_head_lost | -12 tcp_ack | -15 tcp_event_data_recv | -32 tcp_rcv_state_process | -10 tcp_rcv_established | +1 7 functions changed, 6 bytes added, 69 bytes removed, diff: -63 net/ipv4/tcp_output.c: update_send_head | -9 tcp_transmit_skb | +19 tcp_cwnd_validate | +1 tcp_write_wakeup | -17 __tcp_push_pending_frames | -25 tcp_push_one | -8 tcp_send_fin | -4 7 functions changed, 20 bytes added, 63 bytes removed, diff: -43 built-in.o.new: 18 functions changed, 40 bytes added, 178 bytes removed, diff: -138 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-21 05:18:02 +00:00
skb_entail(sk, skb);
copy = size_goal;
}
if (copy > size)
copy = size;
i = skb_shinfo(skb)->nr_frags;
can_coalesce = skb_can_coalesce(skb, i, page, offset);
if (!can_coalesce && i >= sysctl_max_skb_frags) {
tcp_mark_push(tp, skb);
goto new_segment;
}
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 08:11:19 +00:00
if (!sk_wmem_schedule(sk, copy))
goto wait_for_memory;
if (can_coalesce) {
skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
} else {
get_page(page);
skb_fill_page_desc(skb, i, page, offset, copy);
}
if (!(flags & MSG_NO_SHARED_FRAGS))
skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
skb->len += copy;
skb->data_len += copy;
skb->truesize += copy;
sk->sk_wmem_queued += copy;
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 08:11:19 +00:00
sk_mem_charge(sk, copy);
skb->ip_summed = CHECKSUM_PARTIAL;
tp->write_seq += copy;
TCP_SKB_CB(skb)->end_seq += copy;
tcp_skb_pcount_set(skb, 0);
if (!copied)
TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
copied += copy;
offset += copy;
size -= copy;
if (!size)
goto out;
[TCP]: Let skbs grow over a page on fast peers While testing the virtio-net driver on KVM with TSO I noticed that TSO performance with a 1500 MTU is significantly worse compared to the performance of non-TSO with a 16436 MTU. The packet dump shows that most of the packets sent are smaller than a page. Looking at the code this actually is quite obvious as it always stop extending the packet if it's the first packet yet to be sent and if it's larger than the MSS. Since each extension is bound by the page size, this means that (given a 1500 MTU) we're very unlikely to construct packets greater than a page, provided that the receiver and the path is fast enough so that packets can always be sent immediately. The fix is also quite obvious. The push calls inside the loop is just an optimisation so that we don't end up doing all the sending at the end of the loop. Therefore there is no specific reason why it has to do so at MSS boundaries. For TSO, the most natural extension of this optimisation is to do the pushing once the skb exceeds the TSO size goal. This is what the patch does and testing with KVM shows that the TSO performance with a 1500 MTU easily surpasses that of a 16436 MTU and indeed the packet sizes sent are generally larger than 16436. I don't see any obvious downsides for slower peers or connections, but it would be prudent to test this extensively to ensure that those cases don't regress. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-22 22:47:05 +00:00
if (skb->len < size_goal || (flags & MSG_OOB))
continue;
if (forced_push(tp)) {
tcp_mark_push(tp, skb);
[TCP]: Sed magic converts func(sk, tp, ...) -> func(sk, ...) This is (mostly) automated change using magic: sed -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e 's|struct sock \*sk,[\n\t ]*struct tcp_sock \*tp\([^{]*\n{\n\)| struct sock \*sk\1\tstruct tcp_sock *tp = tcp_sk(sk);\n|g' -e 's|struct sock \*sk, struct tcp_sock \*tp| struct sock \*sk|g' -e 's|sk, tp\([^-]\)|sk\1|g' Fixed four unused variable (tp) warnings that were introduced. In addition, manually added newlines after local variables and tweaked function arguments positioning. $ gcc --version gcc (GCC) 4.1.1 20060525 (Red Hat 4.1.1-1) ... $ codiff -fV built-in.o.old built-in.o.new net/ipv4/route.c: rt_cache_flush | +14 1 function changed, 14 bytes added net/ipv4/tcp.c: tcp_setsockopt | -5 tcp_sendpage | -25 tcp_sendmsg | -16 3 functions changed, 46 bytes removed net/ipv4/tcp_input.c: tcp_try_undo_recovery | +3 tcp_try_undo_dsack | +2 tcp_mark_head_lost | -12 tcp_ack | -15 tcp_event_data_recv | -32 tcp_rcv_state_process | -10 tcp_rcv_established | +1 7 functions changed, 6 bytes added, 69 bytes removed, diff: -63 net/ipv4/tcp_output.c: update_send_head | -9 tcp_transmit_skb | +19 tcp_cwnd_validate | +1 tcp_write_wakeup | -17 __tcp_push_pending_frames | -25 tcp_push_one | -8 tcp_send_fin | -4 7 functions changed, 20 bytes added, 63 bytes removed, diff: -43 built-in.o.new: 18 functions changed, 40 bytes added, 178 bytes removed, diff: -138 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-21 05:18:02 +00:00
__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
} else if (skb == tcp_send_head(sk))
tcp_push_one(sk, mss_now);
continue;
wait_for_sndbuf:
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
tcp_push(sk, flags & ~MSG_MORE, mss_now,
TCP_NAGLE_PUSH, size_goal);
err = sk_stream_wait_memory(sk, &timeo);
if (err != 0)
goto do_error;
mss_now = tcp_send_mss(sk, &size_goal, flags);
}
out:
if (copied) {
tcp_tx_timestamp(sk, sk->sk_tsflags);
if (!(flags & MSG_SENDPAGE_NOTLAST))
tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
}
return copied;
do_error:
if (copied)
goto out;
out_err:
/* make sure we wake any epoll edge trigger waiter */
if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 &&
err == -EAGAIN)) {
sk->sk_write_space(sk);
tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
}
return sk_stream_error(sk, flags, err);
}
EXPORT_SYMBOL_GPL(do_tcp_sendpages);
int tcp_sendpage_locked(struct sock *sk, struct page *page, int offset,
size_t size, int flags)
{
if (!(sk->sk_route_caps & NETIF_F_SG))
return sock_no_sendpage_locked(sk, page, offset, size, flags);
tcp: track application-limited rate samples This commit adds code to track whether the delivery rate represented by each rate_sample was limited by the application. Upon each transmit, we store in the is_app_limited field in the skb a boolean bit indicating whether there is a known "bubble in the pipe": a point in the rate sample interval where the sender was application-limited, and did not transmit even though the cwnd and pacing rate allowed it. This logic marks the flow app-limited on a write if *all* of the following are true: 1) There is less than 1 MSS of unsent data in the write queue available to transmit. 2) There is no packet in the sender's queues (e.g. in fq or the NIC tx queue). 3) The connection is not limited by cwnd. 4) There are no lost packets to retransmit. The tcp_rate_check_app_limited() code in tcp_rate.c determines whether the connection is application-limited at the moment. If the flow is application-limited, it sets the tp->app_limited field. If the flow is application-limited then that means there is effectively a "bubble" of silence in the pipe now, and this silence will be reflected in a lower bandwidth sample for any rate samples from now until we get an ACK indicating this bubble has exited the pipe: specifically, until we get an ACK for the next packet we transmit. When we send every skb we record in scb->tx.is_app_limited whether the resulting rate sample will be application-limited. The code in tcp_rate_gen() checks to see when it is safe to mark all known application-limited bubbles of silence as having exited the pipe. It does this by checking to see when the delivered count moves past the tp->app_limited marker. At this point it zeroes the tp->app_limited marker, as all known bubbles are out of the pipe. We make room for the tx.is_app_limited bit in the skb by borrowing a bit from the in_flight field used by NV to record the number of bytes in flight. The receive window in the TCP header is 16 bits, and the max receive window scaling shift factor is 14 (RFC 1323). So the max receive window offered by the TCP protocol is 2^(16+14) = 2^30. So we only need 30 bits for the tx.in_flight used by NV. Signed-off-by: Van Jacobson <vanj@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Nandita Dukkipati <nanditad@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-20 03:39:15 +00:00
tcp_rate_check_app_limited(sk); /* is sending application-limited? */
return do_tcp_sendpages(sk, page, offset, size, flags);
}
EXPORT_SYMBOL_GPL(tcp_sendpage_locked);
int tcp_sendpage(struct sock *sk, struct page *page, int offset,
size_t size, int flags)
{
int ret;
lock_sock(sk);
ret = tcp_sendpage_locked(sk, page, offset, size, flags);
release_sock(sk);
return ret;
}
EXPORT_SYMBOL(tcp_sendpage);
/* Do not bother using a page frag for very small frames.
* But use this heuristic only for the first skb in write queue.
*
* Having no payload in skb->head allows better SACK shifting
* in tcp_shift_skb_data(), reducing sack/rack overhead, because
* write queue has less skbs.
* Each skb can hold up to MAX_SKB_FRAGS * 32Kbytes, or ~0.5 MB.
* This also speeds up tso_fragment(), since it wont fallback
* to tcp_fragment().
*/
static int linear_payload_sz(bool first_skb)
{
if (first_skb)
return SKB_WITH_OVERHEAD(2048 - MAX_TCP_HEADER);
return 0;
}
static int select_size(bool first_skb, bool zc)
{
if (zc)
return 0;
return linear_payload_sz(first_skb);
}
void tcp_free_fastopen_req(struct tcp_sock *tp)
{
if (tp->fastopen_req) {
kfree(tp->fastopen_req);
tp->fastopen_req = NULL;
}
}
static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
int *copied, size_t size)
{
struct tcp_sock *tp = tcp_sk(sk);
net/tcp-fastopen: Add new API support This patch adds a new socket option, TCP_FASTOPEN_CONNECT, as an alternative way to perform Fast Open on the active side (client). Prior to this patch, a client needs to replace the connect() call with sendto(MSG_FASTOPEN). This can be cumbersome for applications who want to use Fast Open: these socket operations are often done in lower layer libraries used by many other applications. Changing these libraries and/or the socket call sequences are not trivial. A more convenient approach is to perform Fast Open by simply enabling a socket option when the socket is created w/o changing other socket calls sequence: s = socket() create a new socket setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT …); newly introduced sockopt If set, new functionality described below will be used. Return ENOTSUPP if TFO is not supported or not enabled in the kernel. connect() With cookie present, return 0 immediately. With no cookie, initiate 3WHS with TFO cookie-request option and return -1 with errno = EINPROGRESS. write()/sendmsg() With cookie present, send out SYN with data and return the number of bytes buffered. With no cookie, and 3WHS not yet completed, return -1 with errno = EINPROGRESS. No MSG_FASTOPEN flag is needed. read() Return -1 with errno = EWOULDBLOCK/EAGAIN if connect() is called but write() is not called yet. Return -1 with errno = EWOULDBLOCK/EAGAIN if connection is established but no msg is received yet. Return number of bytes read if socket is established and there is msg received. The new API simplifies life for applications that always perform a write() immediately after a successful connect(). Such applications can now take advantage of Fast Open by merely making one new setsockopt() call at the time of creating the socket. Nothing else about the application's socket call sequence needs to change. Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-23 18:59:22 +00:00
struct inet_sock *inet = inet_sk(sk);
tcp: avoid fastopen API to be used on AF_UNSPEC Fastopen API should be used to perform fastopen operations on the TCP socket. It does not make sense to use fastopen API to perform disconnect by calling it with AF_UNSPEC. The fastopen data path is also prone to race conditions and bugs when using with AF_UNSPEC. One issue reported and analyzed by Vegard Nossum is as follows: +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Thread A: Thread B: ------------------------------------------------------------------------ sendto() - tcp_sendmsg() - sk_stream_memory_free() = 0 - goto wait_for_sndbuf - sk_stream_wait_memory() - sk_wait_event() // sleep | sendto(flags=MSG_FASTOPEN, dest_addr=AF_UNSPEC) | - tcp_sendmsg() | - tcp_sendmsg_fastopen() | - __inet_stream_connect() | - tcp_disconnect() //because of AF_UNSPEC | - tcp_transmit_skb()// send RST | - return 0; // no reconnect! | - sk_stream_wait_connect() | - sock_error() | - xchg(&sk->sk_err, 0) | - return -ECONNRESET - ... // wake up, see sk->sk_err == 0 - skb_entail() on TCP_CLOSE socket If the connection is reopened then we will send a brand new SYN packet after thread A has already queued a buffer. At this point I think the socket internal state (sequence numbers etc.) becomes messed up. When the new connection is closed, the FIN-ACK is rejected because the sequence number is outside the window. The other side tries to retransmit, but __tcp_retransmit_skb() calls tcp_trim_head() on an empty skb which corrupts the skb data length and hits a BUG() in copy_and_csum_bits(). +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Hence, this patch adds a check for AF_UNSPEC in the fastopen data path and return EOPNOTSUPP to user if such case happens. Fixes: cf60af03ca4e7 ("tcp: Fast Open client - sendmsg(MSG_FASTOPEN)") Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 16:59:31 +00:00
struct sockaddr *uaddr = msg->msg_name;
int err, flags;
if (!(sock_net(sk)->ipv4.sysctl_tcp_fastopen & TFO_CLIENT_ENABLE) ||
tcp: avoid fastopen API to be used on AF_UNSPEC Fastopen API should be used to perform fastopen operations on the TCP socket. It does not make sense to use fastopen API to perform disconnect by calling it with AF_UNSPEC. The fastopen data path is also prone to race conditions and bugs when using with AF_UNSPEC. One issue reported and analyzed by Vegard Nossum is as follows: +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Thread A: Thread B: ------------------------------------------------------------------------ sendto() - tcp_sendmsg() - sk_stream_memory_free() = 0 - goto wait_for_sndbuf - sk_stream_wait_memory() - sk_wait_event() // sleep | sendto(flags=MSG_FASTOPEN, dest_addr=AF_UNSPEC) | - tcp_sendmsg() | - tcp_sendmsg_fastopen() | - __inet_stream_connect() | - tcp_disconnect() //because of AF_UNSPEC | - tcp_transmit_skb()// send RST | - return 0; // no reconnect! | - sk_stream_wait_connect() | - sock_error() | - xchg(&sk->sk_err, 0) | - return -ECONNRESET - ... // wake up, see sk->sk_err == 0 - skb_entail() on TCP_CLOSE socket If the connection is reopened then we will send a brand new SYN packet after thread A has already queued a buffer. At this point I think the socket internal state (sequence numbers etc.) becomes messed up. When the new connection is closed, the FIN-ACK is rejected because the sequence number is outside the window. The other side tries to retransmit, but __tcp_retransmit_skb() calls tcp_trim_head() on an empty skb which corrupts the skb data length and hits a BUG() in copy_and_csum_bits(). +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Hence, this patch adds a check for AF_UNSPEC in the fastopen data path and return EOPNOTSUPP to user if such case happens. Fixes: cf60af03ca4e7 ("tcp: Fast Open client - sendmsg(MSG_FASTOPEN)") Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 16:59:31 +00:00
(uaddr && msg->msg_namelen >= sizeof(uaddr->sa_family) &&
uaddr->sa_family == AF_UNSPEC))
return -EOPNOTSUPP;
if (tp->fastopen_req)
return -EALREADY; /* Another Fast Open is in progress */
tp->fastopen_req = kzalloc(sizeof(struct tcp_fastopen_request),
sk->sk_allocation);
if (unlikely(!tp->fastopen_req))
return -ENOBUFS;
tp->fastopen_req->data = msg;
tp->fastopen_req->size = size;
net/tcp-fastopen: Add new API support This patch adds a new socket option, TCP_FASTOPEN_CONNECT, as an alternative way to perform Fast Open on the active side (client). Prior to this patch, a client needs to replace the connect() call with sendto(MSG_FASTOPEN). This can be cumbersome for applications who want to use Fast Open: these socket operations are often done in lower layer libraries used by many other applications. Changing these libraries and/or the socket call sequences are not trivial. A more convenient approach is to perform Fast Open by simply enabling a socket option when the socket is created w/o changing other socket calls sequence: s = socket() create a new socket setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT …); newly introduced sockopt If set, new functionality described below will be used. Return ENOTSUPP if TFO is not supported or not enabled in the kernel. connect() With cookie present, return 0 immediately. With no cookie, initiate 3WHS with TFO cookie-request option and return -1 with errno = EINPROGRESS. write()/sendmsg() With cookie present, send out SYN with data and return the number of bytes buffered. With no cookie, and 3WHS not yet completed, return -1 with errno = EINPROGRESS. No MSG_FASTOPEN flag is needed. read() Return -1 with errno = EWOULDBLOCK/EAGAIN if connect() is called but write() is not called yet. Return -1 with errno = EWOULDBLOCK/EAGAIN if connection is established but no msg is received yet. Return number of bytes read if socket is established and there is msg received. The new API simplifies life for applications that always perform a write() immediately after a successful connect(). Such applications can now take advantage of Fast Open by merely making one new setsockopt() call at the time of creating the socket. Nothing else about the application's socket call sequence needs to change. Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-23 18:59:22 +00:00
if (inet->defer_connect) {
err = tcp_connect(sk);
/* Same failure procedure as in tcp_v4/6_connect */
if (err) {
tcp_set_state(sk, TCP_CLOSE);
inet->inet_dport = 0;
sk->sk_route_caps = 0;
}
}
flags = (msg->msg_flags & MSG_DONTWAIT) ? O_NONBLOCK : 0;
tcp: avoid fastopen API to be used on AF_UNSPEC Fastopen API should be used to perform fastopen operations on the TCP socket. It does not make sense to use fastopen API to perform disconnect by calling it with AF_UNSPEC. The fastopen data path is also prone to race conditions and bugs when using with AF_UNSPEC. One issue reported and analyzed by Vegard Nossum is as follows: +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Thread A: Thread B: ------------------------------------------------------------------------ sendto() - tcp_sendmsg() - sk_stream_memory_free() = 0 - goto wait_for_sndbuf - sk_stream_wait_memory() - sk_wait_event() // sleep | sendto(flags=MSG_FASTOPEN, dest_addr=AF_UNSPEC) | - tcp_sendmsg() | - tcp_sendmsg_fastopen() | - __inet_stream_connect() | - tcp_disconnect() //because of AF_UNSPEC | - tcp_transmit_skb()// send RST | - return 0; // no reconnect! | - sk_stream_wait_connect() | - sock_error() | - xchg(&sk->sk_err, 0) | - return -ECONNRESET - ... // wake up, see sk->sk_err == 0 - skb_entail() on TCP_CLOSE socket If the connection is reopened then we will send a brand new SYN packet after thread A has already queued a buffer. At this point I think the socket internal state (sequence numbers etc.) becomes messed up. When the new connection is closed, the FIN-ACK is rejected because the sequence number is outside the window. The other side tries to retransmit, but __tcp_retransmit_skb() calls tcp_trim_head() on an empty skb which corrupts the skb data length and hits a BUG() in copy_and_csum_bits(). +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Hence, this patch adds a check for AF_UNSPEC in the fastopen data path and return EOPNOTSUPP to user if such case happens. Fixes: cf60af03ca4e7 ("tcp: Fast Open client - sendmsg(MSG_FASTOPEN)") Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-24 16:59:31 +00:00
err = __inet_stream_connect(sk->sk_socket, uaddr,
net/tcp-fastopen: make connect()'s return case more consistent with non-TFO Without TFO, any subsequent connect() call after a successful one returns -1 EISCONN. The last API update ensured that __inet_stream_connect() can return -1 EINPROGRESS in response to sendmsg() when TFO is in use to indicate that the connection is now in progress. Unfortunately since this function is used both for connect() and sendmsg(), it has the undesired side effect of making connect() now return -1 EINPROGRESS as well after a successful call, while at the same time poll() returns POLLOUT. This can confuse some applications which happen to call connect() and to check for -1 EISCONN to ensure the connection is usable, and for which EINPROGRESS indicates a need to poll, causing a loop. This problem was encountered in haproxy where a call to connect() is precisely used in certain cases to confirm a connection's readiness. While arguably haproxy's behaviour should be improved here, it seems important to aim at a more robust behaviour when the goal of the new API is to make it easier to implement TFO in existing applications. This patch simply ensures that we preserve the same semantics as in the non-TFO case on the connect() syscall when using TFO, while still returning -1 EINPROGRESS on sendmsg(). For this we simply tell __inet_stream_connect() whether we're doing a regular connect() or in fact connecting for a sendmsg() call. Cc: Wei Wang <weiwan@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-25 13:42:46 +00:00
msg->msg_namelen, flags, 1);
/* fastopen_req could already be freed in __inet_stream_connect
* if the connection times out or gets rst
*/
if (tp->fastopen_req) {
*copied = tp->fastopen_req->copied;
tcp_free_fastopen_req(tp);
inet->defer_connect = 0;
}
return err;
}
int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
{
struct tcp_sock *tp = tcp_sk(sk);
struct ubuf_info *uarg = NULL;
struct sk_buff *skb;
struct sockcm_cookie sockc;
int flags, err, copied = 0;
int mss_now = 0, size_goal, copied_syn = 0;
bool process_backlog = false;
bool zc = false;
long timeo;
flags = msg->msg_flags;
if (flags & MSG_ZEROCOPY && size && sock_flag(sk, SOCK_ZEROCOPY)) {
if (sk->sk_state != TCP_ESTABLISHED) {
err = -EINVAL;
goto out_err;
}
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 05:21:27 +00:00
skb = tcp_write_queue_tail(sk);
uarg = sock_zerocopy_realloc(sk, size, skb_zcopy(skb));
if (!uarg) {
err = -ENOBUFS;
goto out_err;
}
zc = sk->sk_route_caps & NETIF_F_SG;
if (!zc)
uarg->zerocopy = 0;
}
if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect) &&
!tp->repair) {
err = tcp_sendmsg_fastopen(sk, msg, &copied_syn, size);
if (err == -EINPROGRESS && copied_syn > 0)
goto out;
else if (err)
goto out_err;
}
timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
tcp: track application-limited rate samples This commit adds code to track whether the delivery rate represented by each rate_sample was limited by the application. Upon each transmit, we store in the is_app_limited field in the skb a boolean bit indicating whether there is a known "bubble in the pipe": a point in the rate sample interval where the sender was application-limited, and did not transmit even though the cwnd and pacing rate allowed it. This logic marks the flow app-limited on a write if *all* of the following are true: 1) There is less than 1 MSS of unsent data in the write queue available to transmit. 2) There is no packet in the sender's queues (e.g. in fq or the NIC tx queue). 3) The connection is not limited by cwnd. 4) There are no lost packets to retransmit. The tcp_rate_check_app_limited() code in tcp_rate.c determines whether the connection is application-limited at the moment. If the flow is application-limited, it sets the tp->app_limited field. If the flow is application-limited then that means there is effectively a "bubble" of silence in the pipe now, and this silence will be reflected in a lower bandwidth sample for any rate samples from now until we get an ACK indicating this bubble has exited the pipe: specifically, until we get an ACK for the next packet we transmit. When we send every skb we record in scb->tx.is_app_limited whether the resulting rate sample will be application-limited. The code in tcp_rate_gen() checks to see when it is safe to mark all known application-limited bubbles of silence as having exited the pipe. It does this by checking to see when the delivered count moves past the tp->app_limited marker. At this point it zeroes the tp->app_limited marker, as all known bubbles are out of the pipe. We make room for the tx.is_app_limited bit in the skb by borrowing a bit from the in_flight field used by NV to record the number of bytes in flight. The receive window in the TCP header is 16 bits, and the max receive window scaling shift factor is 14 (RFC 1323). So the max receive window offered by the TCP protocol is 2^(16+14) = 2^30. So we only need 30 bits for the tx.in_flight used by NV. Signed-off-by: Van Jacobson <vanj@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Nandita Dukkipati <nanditad@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-20 03:39:15 +00:00
tcp_rate_check_app_limited(sk); /* is sending application-limited? */
/* Wait for a connection to finish. One exception is TCP Fast Open
* (passive side) where data is allowed to be sent before a connection
* is fully established.
*/
if (((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) &&
!tcp_passive_fastopen(sk)) {
err = sk_stream_wait_connect(sk, &timeo);
if (err != 0)
goto do_error;
}
tcp: Repair socket queues Reading queues under repair mode is done with recvmsg call. The queue-under-repair set by TCP_REPAIR_QUEUE option is used to determine which queue should be read. Thus both send and receive queue can be read with this. Caller must pass the MSG_PEEK flag. Writing to queues is done with sendmsg call and yet again -- the repair-queue option can be used to push data into the receive queue. When putting an skb into receive queue a zero tcp header is appented to its head to address the tcp_hdr(skb)->syn and the ->fin checks by the (after repair) tcp_recvmsg. These flags flags are both set to zero and that's why. The fin cannot be met in the queue while reading the source socket, since the repair only works for closed/established sockets and queueing fin packet always changes its state. The syn in the queue denotes that the respective skb's seq is "off-by-one" as compared to the actual payload lenght. Thus, at the rcv queue refill we can just drop this flag and set the skb's sequences to precice values. When the repair mode is turned off, the write queue seqs are updated so that the whole queue is considered to be 'already sent, waiting for ACKs' (write_seq = snd_nxt <= snd_una). From the protocol POV the send queue looks like it was sent, but the data between the write_seq and snd_nxt is lost in the network. This helps to avoid another sockoption for setting the snd_nxt sequence. Leaving the whole queue in a 'not yet sent' state (as it will be after sendmsg-s) will not allow to receive any acks from the peer since the ack_seq will be after the snd_nxt. Thus even the ack for the window probe will be dropped and the connection will be 'locked' with the zero peer window. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-19 03:41:01 +00:00
if (unlikely(tp->repair)) {
if (tp->repair_queue == TCP_RECV_QUEUE) {
copied = tcp_send_rcvq(sk, msg, size);
tcp: Fix divide by zero when pushing during tcp-repair When in repair-mode and TCP_RECV_QUEUE is set, we end up calling tcp_push with mss_now being 0. If data is in the send-queue and tcp_set_skb_tso_segs gets called, we crash because it will divide by mss_now: [ 347.151939] divide error: 0000 [#1] SMP [ 347.152907] Modules linked in: [ 347.152907] CPU: 1 PID: 1123 Comm: packetdrill Not tainted 3.16.0-rc2 #4 [ 347.152907] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 347.152907] task: f5b88540 ti: f3c82000 task.ti: f3c82000 [ 347.152907] EIP: 0060:[<c1601359>] EFLAGS: 00210246 CPU: 1 [ 347.152907] EIP is at tcp_set_skb_tso_segs+0x49/0xa0 [ 347.152907] EAX: 00000b67 EBX: f5acd080 ECX: 00000000 EDX: 00000000 [ 347.152907] ESI: f5a28f40 EDI: f3c88f00 EBP: f3c83d10 ESP: f3c83d00 [ 347.152907] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [ 347.152907] CR0: 80050033 CR2: 083158b0 CR3: 35146000 CR4: 000006b0 [ 347.152907] Stack: [ 347.152907] c167f9d9 f5acd080 000005b4 00000002 f3c83d20 c16013e6 f3c88f00 f5acd080 [ 347.152907] f3c83da0 c1603b5a f3c83d38 c10a0188 00000000 00000000 f3c83d84 c10acc85 [ 347.152907] c1ad5ec0 00000000 00000000 c1ad679c 010003e0 00000000 00000000 f3c88fc8 [ 347.152907] Call Trace: [ 347.152907] [<c167f9d9>] ? apic_timer_interrupt+0x2d/0x34 [ 347.152907] [<c16013e6>] tcp_init_tso_segs+0x36/0x50 [ 347.152907] [<c1603b5a>] tcp_write_xmit+0x7a/0xbf0 [ 347.152907] [<c10a0188>] ? up+0x28/0x40 [ 347.152907] [<c10acc85>] ? console_unlock+0x295/0x480 [ 347.152907] [<c10ad24f>] ? vprintk_emit+0x1ef/0x4b0 [ 347.152907] [<c1605716>] __tcp_push_pending_frames+0x36/0xd0 [ 347.152907] [<c15f4860>] tcp_push+0xf0/0x120 [ 347.152907] [<c15f7641>] tcp_sendmsg+0xf1/0xbf0 [ 347.152907] [<c116d920>] ? kmem_cache_free+0xf0/0x120 [ 347.152907] [<c106a682>] ? __sigqueue_free+0x32/0x40 [ 347.152907] [<c106a682>] ? __sigqueue_free+0x32/0x40 [ 347.152907] [<c114f0f0>] ? do_wp_page+0x3e0/0x850 [ 347.152907] [<c161c36a>] inet_sendmsg+0x4a/0xb0 [ 347.152907] [<c1150269>] ? handle_mm_fault+0x709/0xfb0 [ 347.152907] [<c15a006b>] sock_aio_write+0xbb/0xd0 [ 347.152907] [<c1180b79>] do_sync_write+0x69/0xa0 [ 347.152907] [<c1181023>] vfs_write+0x123/0x160 [ 347.152907] [<c1181d55>] SyS_write+0x55/0xb0 [ 347.152907] [<c167f0d8>] sysenter_do_call+0x12/0x28 This can easily be reproduced with the following packetdrill-script (the "magic" with netem, sk_pacing and limit_output_bytes is done to prevent the kernel from pushing all segments, because hitting the limit without doing this is not so easy with packetdrill): 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 +0 < S 0:0(0) win 32792 <mss 1460> +0 > S. 0:0(0) ack 1 <mss 1460> +0.1 < . 1:1(0) ack 1 win 65000 +0 accept(3, ..., ...) = 4 // This forces that not all segments of the snd-queue will be pushed +0 `tc qdisc add dev tun0 root netem delay 10ms` +0 `sysctl -w net.ipv4.tcp_limit_output_bytes=2` +0 setsockopt(4, SOL_SOCKET, 47, [2], 4) = 0 +0 write(4,...,10000) = 10000 +0 write(4,...,10000) = 10000 // Set tcp-repair stuff, particularly TCP_RECV_QUEUE +0 setsockopt(4, SOL_TCP, 19, [1], 4) = 0 +0 setsockopt(4, SOL_TCP, 20, [1], 4) = 0 // This now will make the write push the remaining segments +0 setsockopt(4, SOL_SOCKET, 47, [20000], 4) = 0 +0 `sysctl -w net.ipv4.tcp_limit_output_bytes=130000` // Now we will crash +0 write(4,...,1000) = 1000 This happens since ec3423257508 (tcp: fix retransmission in repair mode). Prior to that, the call to tcp_push was prevented by a check for tp->repair. The patch fixes it, by adding the new goto-label out_nopush. When exiting tcp_sendmsg and a push is not required, which is the case for tp->repair, we go to this label. When repairing and calling send() with TCP_RECV_QUEUE, the data is actually put in the receive-queue. So, no push is required because no data has been added to the send-queue. Cc: Andrew Vagin <avagin@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Fixes: ec3423257508 (tcp: fix retransmission in repair mode) Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be> Acked-by: Andrew Vagin <avagin@openvz.org> Acked-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-28 16:26:37 +00:00
goto out_nopush;
tcp: Repair socket queues Reading queues under repair mode is done with recvmsg call. The queue-under-repair set by TCP_REPAIR_QUEUE option is used to determine which queue should be read. Thus both send and receive queue can be read with this. Caller must pass the MSG_PEEK flag. Writing to queues is done with sendmsg call and yet again -- the repair-queue option can be used to push data into the receive queue. When putting an skb into receive queue a zero tcp header is appented to its head to address the tcp_hdr(skb)->syn and the ->fin checks by the (after repair) tcp_recvmsg. These flags flags are both set to zero and that's why. The fin cannot be met in the queue while reading the source socket, since the repair only works for closed/established sockets and queueing fin packet always changes its state. The syn in the queue denotes that the respective skb's seq is "off-by-one" as compared to the actual payload lenght. Thus, at the rcv queue refill we can just drop this flag and set the skb's sequences to precice values. When the repair mode is turned off, the write queue seqs are updated so that the whole queue is considered to be 'already sent, waiting for ACKs' (write_seq = snd_nxt <= snd_una). From the protocol POV the send queue looks like it was sent, but the data between the write_seq and snd_nxt is lost in the network. This helps to avoid another sockoption for setting the snd_nxt sequence. Leaving the whole queue in a 'not yet sent' state (as it will be after sendmsg-s) will not allow to receive any acks from the peer since the ack_seq will be after the snd_nxt. Thus even the ack for the window probe will be dropped and the connection will be 'locked' with the zero peer window. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-19 03:41:01 +00:00
}
err = -EINVAL;
if (tp->repair_queue == TCP_NO_QUEUE)
goto out_err;
/* 'common' sending to sendq */
}
sockcm_init(&sockc, sk);
if (msg->msg_controllen) {
err = sock_cmsg_send(sk, msg, &sockc);
if (unlikely(err)) {
err = -EINVAL;
goto out_err;
}
}
/* This should be in poll */
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
/* Ok commence sending. */
copied = 0;
tcp: make tcp_sendmsg() aware of socket backlog Large sendmsg()/write() hold socket lock for the duration of the call, unless sk->sk_sndbuf limit is hit. This is bad because incoming packets are parked into socket backlog for a long time. Critical decisions like fast retransmit might be delayed. Receivers have to maintain a big out of order queue with additional cpu overhead, and also possible stalls in TX once windows are full. Bidirectional flows are particularly hurt since the backlog can become quite big if the copy from user space triggers IO (page faults) Some applications learnt to use sendmsg() (or sendmmsg()) with small chunks to avoid this issue. Kernel should know better, right ? Add a generic sk_flush_backlog() helper and use it right before a new skb is allocated. Typically we put 64KB of payload per skb (unless MSG_EOR is requested) and checking socket backlog every 64KB gives good results. As a matter of fact, tests with TSO/GSO disabled give very nice results, as we manage to keep a small write queue and smaller perceived rtt. Note that sk_flush_backlog() maintains socket ownership, so is not equivalent to a {release_sock(sk); lock_sock(sk);}, to ensure implicit atomicity rules that sendmsg() was giving to (possibly buggy) applications. In this simple implementation, I chose to not call tcp_release_cb(), but we might consider this later. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-29 21:16:53 +00:00
restart:
mss_now = tcp_send_mss(sk, &size_goal, flags);
err = -EPIPE;
if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
goto do_error;
while (msg_data_left(msg)) {
int copy = 0;
skb = tcp_write_queue_tail(sk);
if (skb)
copy = size_goal - skb->len;
tcp: Make use of MSG_EOR in tcp_sendmsg This patch adds an eor bit to the TCP_SKB_CB. When MSG_EOR is passed to tcp_sendmsg, the eor bit will be set at the skb containing the last byte of the userland's msg. The eor bit will prevent data from appending to that skb in the future. The change in do_tcp_sendpages is to honor the eor set during the previous tcp_sendmsg(MSG_EOR) call. This patch handles the tcp_sendmsg case. The followup patches will handle other skb coalescing and fragment cases. One potential use case is to use MSG_EOR with SOF_TIMESTAMPING_TX_ACK to get a more accurate TCP ack timestamping on application protocol with multiple outgoing response messages (e.g. HTTP2). Packetdrill script for testing: ~~~~~~ +0 `sysctl -q -w net.ipv4.tcp_min_tso_segs=10` +0 `sysctl -q -w net.ipv4.tcp_no_metrics_save=1` +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 0.100 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,nop,wscale 7> 0.100 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7> 0.200 < . 1:1(0) ack 1 win 257 0.200 accept(3, ..., ...) = 4 +0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 0.200 write(4, ..., 14600) = 14600 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 0.200 > . 1:7301(7300) ack 1 0.200 > P. 7301:14601(7300) ack 1 0.300 < . 1:1(0) ack 14601 win 257 0.300 > P. 14601:15331(730) ack 1 0.300 > P. 15331:16061(730) ack 1 0.400 < . 1:1(0) ack 16061 win 257 0.400 close(4) = 0 0.400 > F. 16061:16061(0) ack 1 0.400 < F. 1:1(0) ack 16062 win 257 0.400 > . 16062:16062(0) ack 2 Signed-off-by: Martin KaFai Lau <kafai@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Willem de Bruijn <willemb@google.com> Cc: Yuchung Cheng <ycheng@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-25 21:44:48 +00:00
if (copy <= 0 || !tcp_skb_can_collapse_to(skb)) {
bool first_skb;
int linear;
new_segment:
if (!sk_stream_memory_free(sk))
goto wait_for_sndbuf;
if (process_backlog && sk_flush_backlog(sk)) {
process_backlog = false;
tcp: make tcp_sendmsg() aware of socket backlog Large sendmsg()/write() hold socket lock for the duration of the call, unless sk->sk_sndbuf limit is hit. This is bad because incoming packets are parked into socket backlog for a long time. Critical decisions like fast retransmit might be delayed. Receivers have to maintain a big out of order queue with additional cpu overhead, and also possible stalls in TX once windows are full. Bidirectional flows are particularly hurt since the backlog can become quite big if the copy from user space triggers IO (page faults) Some applications learnt to use sendmsg() (or sendmmsg()) with small chunks to avoid this issue. Kernel should know better, right ? Add a generic sk_flush_backlog() helper and use it right before a new skb is allocated. Typically we put 64KB of payload per skb (unless MSG_EOR is requested) and checking socket backlog every 64KB gives good results. As a matter of fact, tests with TSO/GSO disabled give very nice results, as we manage to keep a small write queue and smaller perceived rtt. Note that sk_flush_backlog() maintains socket ownership, so is not equivalent to a {release_sock(sk); lock_sock(sk);}, to ensure implicit atomicity rules that sendmsg() was giving to (possibly buggy) applications. In this simple implementation, I chose to not call tcp_release_cb(), but we might consider this later. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-29 21:16:53 +00:00
goto restart;
}
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 05:21:27 +00:00
first_skb = tcp_rtx_and_write_queues_empty(sk);
linear = select_size(first_skb, zc);
skb = sk_stream_alloc_skb(sk, linear, sk->sk_allocation,
first_skb);
if (!skb)
goto wait_for_memory;
process_backlog = true;
skb->ip_summed = CHECKSUM_PARTIAL;
skb_entail(sk, skb);
copy = size_goal;
tcp: don't use timestamp from repaired skb-s to calculate RTT (v2) We don't know right timestamp for repaired skb-s. Wrong RTT estimations isn't good, because some congestion modules heavily depends on it. This patch adds the TCPCB_REPAIRED flag, which is included in TCPCB_RETRANS. Thanks to Eric for the advice how to fix this issue. This patch fixes the warning: [ 879.562947] WARNING: CPU: 0 PID: 2825 at net/ipv4/tcp_input.c:3078 tcp_ack+0x11f5/0x1380() [ 879.567253] CPU: 0 PID: 2825 Comm: socket-tcpbuf-l Not tainted 3.16.0-next-20140811 #1 [ 879.567829] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 879.568177] 0000000000000000 00000000c532680c ffff880039643d00 ffffffff817aa2d2 [ 879.568776] 0000000000000000 ffff880039643d38 ffffffff8109afbd ffff880039d6ba80 [ 879.569386] ffff88003a449800 000000002983d6bd 0000000000000000 000000002983d6bc [ 879.569982] Call Trace: [ 879.570264] [<ffffffff817aa2d2>] dump_stack+0x4d/0x66 [ 879.570599] [<ffffffff8109afbd>] warn_slowpath_common+0x7d/0xa0 [ 879.570935] [<ffffffff8109b0ea>] warn_slowpath_null+0x1a/0x20 [ 879.571292] [<ffffffff816d0a05>] tcp_ack+0x11f5/0x1380 [ 879.571614] [<ffffffff816d10bd>] tcp_rcv_established+0x1ed/0x710 [ 879.571958] [<ffffffff816dc9da>] tcp_v4_do_rcv+0x10a/0x370 [ 879.572315] [<ffffffff81657459>] release_sock+0x89/0x1d0 [ 879.572642] [<ffffffff816c81a0>] do_tcp_setsockopt.isra.36+0x120/0x860 [ 879.573000] [<ffffffff8110a52e>] ? rcu_read_lock_held+0x6e/0x80 [ 879.573352] [<ffffffff816c8912>] tcp_setsockopt+0x32/0x40 [ 879.573678] [<ffffffff81654ac4>] sock_common_setsockopt+0x14/0x20 [ 879.574031] [<ffffffff816537b0>] SyS_setsockopt+0x80/0xf0 [ 879.574393] [<ffffffff817b40a9>] system_call_fastpath+0x16/0x1b [ 879.574730] ---[ end trace a17cbc38eb8c5c00 ]--- v2: moving setting of skb->when for repaired skb-s in tcp_write_xmit, where it's set for other skb-s. Fixes: 431a91242d8d ("tcp: timestamp SYN+DATA messages") Fixes: 740b0f1841f6 ("tcp: switch rtt estimations to usec resolution") Cc: Eric Dumazet <edumazet@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrey Vagin <avagin@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-13 12:03:10 +00:00
/* All packets are restored as if they have
* already been sent. skb_mstamp_ns isn't set to
* avoid wrong rtt estimation.
*/
if (tp->repair)
TCP_SKB_CB(skb)->sacked |= TCPCB_REPAIRED;
}
/* Try to append data to the end of skb. */
if (copy > msg_data_left(msg))
copy = msg_data_left(msg);
/* Where to copy to? */
if (skb_availroom(skb) > 0 && !zc) {
/* We have some space in skb head. Superb! */
copy = min_t(int, copy, skb_availroom(skb));
err = skb_add_data_nocache(sk, skb, &msg->msg_iter, copy);
if (err)
goto do_fault;
} else if (!zc) {
bool merge = true;
int i = skb_shinfo(skb)->nr_frags;
struct page_frag *pfrag = sk_page_frag(sk);
if (!sk_page_frag_refill(sk, pfrag))
goto wait_for_memory;
if (!skb_can_coalesce(skb, i, pfrag->page,
pfrag->offset)) {
if (i >= sysctl_max_skb_frags) {
tcp_mark_push(tp, skb);
goto new_segment;
}
merge = false;
}
copy = min_t(int, copy, pfrag->size - pfrag->offset);
if (!sk_wmem_schedule(sk, copy))
goto wait_for_memory;
err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
pfrag->page,
pfrag->offset,
copy);
if (err)
goto do_error;
/* Update the skb. */
if (merge) {
skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
} else {
skb_fill_page_desc(skb, i, pfrag->page,
pfrag->offset, copy);
page_ref_inc(pfrag->page);
net-timestamp: TCP timestamping TCP timestamping extends SO_TIMESTAMPING to bytestreams. Bytestreams do not have a 1:1 relationship between send() buffers and network packets. The feature interprets a send call on a bytestream as a request for a timestamp for the last byte in that send() buffer. The choice corresponds to a request for a timestamp when all bytes in the buffer have been sent. That assumption depends on in-order kernel transmission. This is the common case. That said, it is possible to construct a traffic shaping tree that would result in reordering. The guarantee is strong, then, but not ironclad. This implementation supports send and sendpages (splice). GSO replaces one large packet with multiple smaller packets. This patch also copies the option into the correct smaller packet. This patch does not yet support timestamping on data in an initial TCP Fast Open SYN, because that takes a very different data path. If ID generation in ee_data is enabled, bytestream timestamps return a byte offset, instead of the packet counter for datagrams. The implementation supports a single timestamp per packet. It silenty replaces requests for previous timestamps. To avoid missing tstamps, flush the tcp queue by disabling Nagle, cork and autocork. Missing tstamps can be detected by offset when the ee_data ID is enabled. Implementation details: - On GSO, the timestamping code can be included in the main loop. I moved it into its own loop to reduce the impact on the common case to a single branch. - To avoid leaking the absolute seqno to userspace, the offset returned in ee_data must always be relative. It is an offset between an skb and sk field. The first is always set (also for GSO & ACK). The second must also never be uninitialized. Only allow the ID option on sockets in the ESTABLISHED state, for which the seqno is available. Never reset it to zero (instead, move it to the current seqno when reenabling the option). Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 02:11:49 +00:00
}
pfrag->offset += copy;
} else {
err = skb_zerocopy_iter_stream(sk, skb, msg, copy, uarg);
if (err == -EMSGSIZE || err == -EEXIST) {
tcp_mark_push(tp, skb);
goto new_segment;
}
if (err < 0)
goto do_error;
copy = err;
}
if (!copied)
TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;
tp->write_seq += copy;
TCP_SKB_CB(skb)->end_seq += copy;
tcp_skb_pcount_set(skb, 0);
copied += copy;
if (!msg_data_left(msg)) {
tcp: Make use of MSG_EOR in tcp_sendmsg This patch adds an eor bit to the TCP_SKB_CB. When MSG_EOR is passed to tcp_sendmsg, the eor bit will be set at the skb containing the last byte of the userland's msg. The eor bit will prevent data from appending to that skb in the future. The change in do_tcp_sendpages is to honor the eor set during the previous tcp_sendmsg(MSG_EOR) call. This patch handles the tcp_sendmsg case. The followup patches will handle other skb coalescing and fragment cases. One potential use case is to use MSG_EOR with SOF_TIMESTAMPING_TX_ACK to get a more accurate TCP ack timestamping on application protocol with multiple outgoing response messages (e.g. HTTP2). Packetdrill script for testing: ~~~~~~ +0 `sysctl -q -w net.ipv4.tcp_min_tso_segs=10` +0 `sysctl -q -w net.ipv4.tcp_no_metrics_save=1` +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 0.100 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,nop,wscale 7> 0.100 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7> 0.200 < . 1:1(0) ack 1 win 257 0.200 accept(3, ..., ...) = 4 +0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 0.200 write(4, ..., 14600) = 14600 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 0.200 sendto(4, ..., 730, MSG_EOR, ..., ...) = 730 0.200 > . 1:7301(7300) ack 1 0.200 > P. 7301:14601(7300) ack 1 0.300 < . 1:1(0) ack 14601 win 257 0.300 > P. 14601:15331(730) ack 1 0.300 > P. 15331:16061(730) ack 1 0.400 < . 1:1(0) ack 16061 win 257 0.400 close(4) = 0 0.400 > F. 16061:16061(0) ack 1 0.400 < F. 1:1(0) ack 16062 win 257 0.400 > . 16062:16062(0) ack 2 Signed-off-by: Martin KaFai Lau <kafai@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Willem de Bruijn <willemb@google.com> Cc: Yuchung Cheng <ycheng@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-25 21:44:48 +00:00
if (unlikely(flags & MSG_EOR))
TCP_SKB_CB(skb)->eor = 1;
goto out;
}
if (skb->len < size_goal || (flags & MSG_OOB) || unlikely(tp->repair))
continue;
if (forced_push(tp)) {
tcp_mark_push(tp, skb);
__tcp_push_pending_frames(sk, mss_now, TCP_NAGLE_PUSH);
} else if (skb == tcp_send_head(sk))
tcp_push_one(sk, mss_now);
continue;
wait_for_sndbuf:
set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
if (copied)
tcp_push(sk, flags & ~MSG_MORE, mss_now,
TCP_NAGLE_PUSH, size_goal);
err = sk_stream_wait_memory(sk, &timeo);
if (err != 0)
goto do_error;
mss_now = tcp_send_mss(sk, &size_goal, flags);
}
out:
if (copied) {
tcp_tx_timestamp(sk, sockc.tsflags);
tcp: auto corking With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 06:36:05 +00:00
tcp_push(sk, flags, mss_now, tp->nonagle, size_goal);
}
tcp: Fix divide by zero when pushing during tcp-repair When in repair-mode and TCP_RECV_QUEUE is set, we end up calling tcp_push with mss_now being 0. If data is in the send-queue and tcp_set_skb_tso_segs gets called, we crash because it will divide by mss_now: [ 347.151939] divide error: 0000 [#1] SMP [ 347.152907] Modules linked in: [ 347.152907] CPU: 1 PID: 1123 Comm: packetdrill Not tainted 3.16.0-rc2 #4 [ 347.152907] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 [ 347.152907] task: f5b88540 ti: f3c82000 task.ti: f3c82000 [ 347.152907] EIP: 0060:[<c1601359>] EFLAGS: 00210246 CPU: 1 [ 347.152907] EIP is at tcp_set_skb_tso_segs+0x49/0xa0 [ 347.152907] EAX: 00000b67 EBX: f5acd080 ECX: 00000000 EDX: 00000000 [ 347.152907] ESI: f5a28f40 EDI: f3c88f00 EBP: f3c83d10 ESP: f3c83d00 [ 347.152907] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 [ 347.152907] CR0: 80050033 CR2: 083158b0 CR3: 35146000 CR4: 000006b0 [ 347.152907] Stack: [ 347.152907] c167f9d9 f5acd080 000005b4 00000002 f3c83d20 c16013e6 f3c88f00 f5acd080 [ 347.152907] f3c83da0 c1603b5a f3c83d38 c10a0188 00000000 00000000 f3c83d84 c10acc85 [ 347.152907] c1ad5ec0 00000000 00000000 c1ad679c 010003e0 00000000 00000000 f3c88fc8 [ 347.152907] Call Trace: [ 347.152907] [<c167f9d9>] ? apic_timer_interrupt+0x2d/0x34 [ 347.152907] [<c16013e6>] tcp_init_tso_segs+0x36/0x50 [ 347.152907] [<c1603b5a>] tcp_write_xmit+0x7a/0xbf0 [ 347.152907] [<c10a0188>] ? up+0x28/0x40 [ 347.152907] [<c10acc85>] ? console_unlock+0x295/0x480 [ 347.152907] [<c10ad24f>] ? vprintk_emit+0x1ef/0x4b0 [ 347.152907] [<c1605716>] __tcp_push_pending_frames+0x36/0xd0 [ 347.152907] [<c15f4860>] tcp_push+0xf0/0x120 [ 347.152907] [<c15f7641>] tcp_sendmsg+0xf1/0xbf0 [ 347.152907] [<c116d920>] ? kmem_cache_free+0xf0/0x120 [ 347.152907] [<c106a682>] ? __sigqueue_free+0x32/0x40 [ 347.152907] [<c106a682>] ? __sigqueue_free+0x32/0x40 [ 347.152907] [<c114f0f0>] ? do_wp_page+0x3e0/0x850 [ 347.152907] [<c161c36a>] inet_sendmsg+0x4a/0xb0 [ 347.152907] [<c1150269>] ? handle_mm_fault+0x709/0xfb0 [ 347.152907] [<c15a006b>] sock_aio_write+0xbb/0xd0 [ 347.152907] [<c1180b79>] do_sync_write+0x69/0xa0 [ 347.152907] [<c1181023>] vfs_write+0x123/0x160 [ 347.152907] [<c1181d55>] SyS_write+0x55/0xb0 [ 347.152907] [<c167f0d8>] sysenter_do_call+0x12/0x28 This can easily be reproduced with the following packetdrill-script (the "magic" with netem, sk_pacing and limit_output_bytes is done to prevent the kernel from pushing all segments, because hitting the limit without doing this is not so easy with packetdrill): 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 +0 < S 0:0(0) win 32792 <mss 1460> +0 > S. 0:0(0) ack 1 <mss 1460> +0.1 < . 1:1(0) ack 1 win 65000 +0 accept(3, ..., ...) = 4 // This forces that not all segments of the snd-queue will be pushed +0 `tc qdisc add dev tun0 root netem delay 10ms` +0 `sysctl -w net.ipv4.tcp_limit_output_bytes=2` +0 setsockopt(4, SOL_SOCKET, 47, [2], 4) = 0 +0 write(4,...,10000) = 10000 +0 write(4,...,10000) = 10000 // Set tcp-repair stuff, particularly TCP_RECV_QUEUE +0 setsockopt(4, SOL_TCP, 19, [1], 4) = 0 +0 setsockopt(4, SOL_TCP, 20, [1], 4) = 0 // This now will make the write push the remaining segments +0 setsockopt(4, SOL_SOCKET, 47, [20000], 4) = 0 +0 `sysctl -w net.ipv4.tcp_limit_output_bytes=130000` // Now we will crash +0 write(4,...,1000) = 1000 This happens since ec3423257508 (tcp: fix retransmission in repair mode). Prior to that, the call to tcp_push was prevented by a check for tp->repair. The patch fixes it, by adding the new goto-label out_nopush. When exiting tcp_sendmsg and a push is not required, which is the case for tp->repair, we go to this label. When repairing and calling send() with TCP_RECV_QUEUE, the data is actually put in the receive-queue. So, no push is required because no data has been added to the send-queue. Cc: Andrew Vagin <avagin@openvz.org> Cc: Pavel Emelyanov <xemul@parallels.com> Fixes: ec3423257508 (tcp: fix retransmission in repair mode) Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be> Acked-by: Andrew Vagin <avagin@openvz.org> Acked-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-28 16:26:37 +00:00
out_nopush:
sock_zerocopy_put(uarg);
return copied + copied_syn;
do_fault:
if (!skb->len) {
tcp_unlink_write_queue(skb, sk);
/* It is the one place in all of TCP, except connection
* reset, where we can be unlinking the send_head.
*/
tcp_check_send_head(sk, skb);
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 08:11:19 +00:00
sk_wmem_free_skb(sk, skb);
}
do_error:
if (copied + copied_syn)
goto out;
out_err:
sock_zerocopy_put_abort(uarg, true);
err = sk_stream_error(sk, flags, err);
/* make sure we wake any epoll edge trigger waiter */
if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 &&
err == -EAGAIN)) {
sk->sk_write_space(sk);
tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED);
}
return err;
}
EXPORT_SYMBOL_GPL(tcp_sendmsg_locked);
int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
{
int ret;
lock_sock(sk);
ret = tcp_sendmsg_locked(sk, msg, size);
release_sock(sk);
return ret;
}
EXPORT_SYMBOL(tcp_sendmsg);
/*
* Handle reading urgent data. BSD has very simple semantics for
* this, no blocking and very strange errors 8)
*/
static int tcp_recv_urg(struct sock *sk, struct msghdr *msg, int len, int flags)
{
struct tcp_sock *tp = tcp_sk(sk);
/* No URG data to read. */
if (sock_flag(sk, SOCK_URGINLINE) || !tp->urg_data ||
tp->urg_data == TCP_URG_READ)
return -EINVAL; /* Yes this is right ! */
if (sk->sk_state == TCP_CLOSE && !sock_flag(sk, SOCK_DONE))
return -ENOTCONN;
if (tp->urg_data & TCP_URG_VALID) {
int err = 0;
char c = tp->urg_data;
if (!(flags & MSG_PEEK))
tp->urg_data = TCP_URG_READ;
/* Read urgent data. */
msg->msg_flags |= MSG_OOB;
if (len > 0) {
if (!(flags & MSG_TRUNC))
err = memcpy_to_msg(msg, &c, 1);
len = 1;
} else
msg->msg_flags |= MSG_TRUNC;
return err ? -EFAULT : len;
}
if (sk->sk_state == TCP_CLOSE || (sk->sk_shutdown & RCV_SHUTDOWN))
return 0;
/* Fixed the recv(..., MSG_OOB) behaviour. BSD docs and
* the available implementations agree in this case:
* this call should never block, independent of the
* blocking state of the socket.
* Mike <pall@rz.uni-karlsruhe.de>
*/
return -EAGAIN;
}
tcp: Repair socket queues Reading queues under repair mode is done with recvmsg call. The queue-under-repair set by TCP_REPAIR_QUEUE option is used to determine which queue should be read. Thus both send and receive queue can be read with this. Caller must pass the MSG_PEEK flag. Writing to queues is done with sendmsg call and yet again -- the repair-queue option can be used to push data into the receive queue. When putting an skb into receive queue a zero tcp header is appented to its head to address the tcp_hdr(skb)->syn and the ->fin checks by the (after repair) tcp_recvmsg. These flags flags are both set to zero and that's why. The fin cannot be met in the queue while reading the source socket, since the repair only works for closed/established sockets and queueing fin packet always changes its state. The syn in the queue denotes that the respective skb's seq is "off-by-one" as compared to the actual payload lenght. Thus, at the rcv queue refill we can just drop this flag and set the skb's sequences to precice values. When the repair mode is turned off, the write queue seqs are updated so that the whole queue is considered to be 'already sent, waiting for ACKs' (write_seq = snd_nxt <= snd_una). From the protocol POV the send queue looks like it was sent, but the data between the write_seq and snd_nxt is lost in the network. This helps to avoid another sockoption for setting the snd_nxt sequence. Leaving the whole queue in a 'not yet sent' state (as it will be after sendmsg-s) will not allow to receive any acks from the peer since the ack_seq will be after the snd_nxt. Thus even the ack for the window probe will be dropped and the connection will be 'locked' with the zero peer window. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-19 03:41:01 +00:00
static int tcp_peek_sndq(struct sock *sk, struct msghdr *msg, int len)
{
struct sk_buff *skb;
int copied = 0, err = 0;
/* XXX -- need to support SO_PEEK_OFF */
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 05:21:27 +00:00
skb_rbtree_walk(skb, &sk->tcp_rtx_queue) {
err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
if (err)
return err;
copied += skb->len;
}
tcp: Repair socket queues Reading queues under repair mode is done with recvmsg call. The queue-under-repair set by TCP_REPAIR_QUEUE option is used to determine which queue should be read. Thus both send and receive queue can be read with this. Caller must pass the MSG_PEEK flag. Writing to queues is done with sendmsg call and yet again -- the repair-queue option can be used to push data into the receive queue. When putting an skb into receive queue a zero tcp header is appented to its head to address the tcp_hdr(skb)->syn and the ->fin checks by the (after repair) tcp_recvmsg. These flags flags are both set to zero and that's why. The fin cannot be met in the queue while reading the source socket, since the repair only works for closed/established sockets and queueing fin packet always changes its state. The syn in the queue denotes that the respective skb's seq is "off-by-one" as compared to the actual payload lenght. Thus, at the rcv queue refill we can just drop this flag and set the skb's sequences to precice values. When the repair mode is turned off, the write queue seqs are updated so that the whole queue is considered to be 'already sent, waiting for ACKs' (write_seq = snd_nxt <= snd_una). From the protocol POV the send queue looks like it was sent, but the data between the write_seq and snd_nxt is lost in the network. This helps to avoid another sockoption for setting the snd_nxt sequence. Leaving the whole queue in a 'not yet sent' state (as it will be after sendmsg-s) will not allow to receive any acks from the peer since the ack_seq will be after the snd_nxt. Thus even the ack for the window probe will be dropped and the connection will be 'locked' with the zero peer window. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-19 03:41:01 +00:00
skb_queue_walk(&sk->sk_write_queue, skb) {
err = skb_copy_datagram_msg(skb, 0, msg, skb->len);
tcp: Repair socket queues Reading queues under repair mode is done with recvmsg call. The queue-under-repair set by TCP_REPAIR_QUEUE option is used to determine which queue should be read. Thus both send and receive queue can be read with this. Caller must pass the MSG_PEEK flag. Writing to queues is done with sendmsg call and yet again -- the repair-queue option can be used to push data into the receive queue. When putting an skb into receive queue a zero tcp header is appented to its head to address the tcp_hdr(skb)->syn and the ->fin checks by the (after repair) tcp_recvmsg. These flags flags are both set to zero and that's why. The fin cannot be met in the queue while reading the source socket, since the repair only works for closed/established sockets and queueing fin packet always changes its state. The syn in the queue denotes that the respective skb's seq is "off-by-one" as compared to the actual payload lenght. Thus, at the rcv queue refill we can just drop this flag and set the skb's sequences to precice values. When the repair mode is turned off, the write queue seqs are updated so that the whole queue is considered to be 'already sent, waiting for ACKs' (write_seq = snd_nxt <= snd_una). From the protocol POV the send queue looks like it was sent, but the data between the write_seq and snd_nxt is lost in the network. This helps to avoid another sockoption for setting the snd_nxt sequence. Leaving the whole queue in a 'not yet sent' state (as it will be after sendmsg-s) will not allow to receive any acks from the peer since the ack_seq will be after the snd_nxt. Thus even the ack for the window probe will be dropped and the connection will be 'locked' with the zero peer window. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-19 03:41:01 +00:00
if (err)
break;
copied += skb->len;
}
return err ?: copied;
}
/* Clean up the receive buffer for full frames taken by the user,
* then send an ACK if necessary. COPIED is the number of bytes
* tcp_recvmsg has given to the user so far, it speeds up the
* calculation of whether or not we must ACK for the sake of
* a window update.
*/
static void tcp_cleanup_rbuf(struct sock *sk, int copied)
{
struct tcp_sock *tp = tcp_sk(sk);
bool time_to_ack = false;
struct sk_buff *skb = skb_peek(&sk->sk_receive_queue);
WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq),
"cleanup rbuf bug: copied %X seq %X rcvnxt %X\n",
tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt);
if (inet_csk_ack_scheduled(sk)) {
const struct inet_connection_sock *icsk = inet_csk(sk);
/* Delayed ACKs frequently hit locked sockets during bulk
* receive. */
if (icsk->icsk_ack.blocked ||
/* Once-per-two-segments ACK was not sent by tcp_input.c */
tp->rcv_nxt - tp->rcv_wup > icsk->icsk_ack.rcv_mss ||
/*
* If this read emptied read buffer, we send ACK, if
* connection is not bidirectional, user drained
* receive buffer and there was a small segment
* in queue.
*/
(copied > 0 &&
((icsk->icsk_ack.pending & ICSK_ACK_PUSHED2) ||
((icsk->icsk_ack.pending & ICSK_ACK_PUSHED) &&
!icsk->icsk_ack.pingpong)) &&
!atomic_read(&sk->sk_rmem_alloc)))
time_to_ack = true;
}
/* We send an ACK if we can now advertise a non-zero window
* which has been raised "significantly".
*
* Even if window raised up to infinity, do not send window open ACK
* in states, where we will not receive more. It is useless.
*/
if (copied > 0 && !time_to_ack && !(sk->sk_shutdown & RCV_SHUTDOWN)) {
__u32 rcv_window_now = tcp_receive_window(tp);
/* Optimize, __tcp_select_window() is not cheap. */
if (2*rcv_window_now <= tp->window_clamp) {
__u32 new_window = __tcp_select_window(sk);
/* Send ACK now, if this read freed lots of space
* in our buffer. Certainly, new_window is new window.
* We can advertise it now, if it is not less than current one.
* "Lots" means "at least twice" here.
*/
if (new_window && new_window >= 2 * rcv_window_now)
time_to_ack = true;
}
}
if (time_to_ack)
tcp_send_ack(sk);
}
static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
{
struct sk_buff *skb;
u32 offset;
while ((skb = skb_peek(&sk->sk_receive_queue)) != NULL) {
offset = seq - TCP_SKB_CB(skb)->seq;
if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
pr_err_once("%s: found a SYN, please report !\n", __func__);
offset--;
}
if (offset < skb->len || (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) {
*off = offset;
return skb;
}
/* This looks weird, but this can happen if TCP collapsing
* splitted a fat GRO packet, while we released socket lock
* in skb_splice_bits()
*/
sk_eat_skb(sk, skb);
}
return NULL;
}
/*
* This routine provides an alternative to tcp_recvmsg() for routines
* that would like to handle copying from skbuffs directly in 'sendfile'
* fashion.
* Note:
* - It is assumed that the socket was locked by the caller.
* - The routine does not block.
* - At present, there is no support for reading OOB data
* or for 'peeking' the socket using this routine
* (although both would be easy to implement).
*/
int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
sk_read_actor_t recv_actor)
{
struct sk_buff *skb;
struct tcp_sock *tp = tcp_sk(sk);
u32 seq = tp->copied_seq;
u32 offset;
int copied = 0;
if (sk->sk_state == TCP_LISTEN)
return -ENOTCONN;
while ((skb = tcp_recv_skb(sk, seq, &offset)) != NULL) {
if (offset < skb->len) {
int used;
size_t len;
len = skb->len - offset;
/* Stop reading if we hit a patch of urgent data */
if (tp->urg_data) {
u32 urg_offset = tp->urg_seq - seq;
if (urg_offset < len)
len = urg_offset;
if (!len)
break;
}
used = recv_actor(desc, skb, offset, len);
tcp: splice: fix an infinite loop in tcp_read_sock() commit 02275a2ee7c0 (tcp: don't abort splice() after small transfers) added a regression. [ 83.843570] INFO: rcu_sched self-detected stall on CPU [ 83.844575] INFO: rcu_sched detected stalls on CPUs/tasks: { 6} (detected by 0, t=21002 jiffies, g=4457, c=4456, q=13132) [ 83.844582] Task dump for CPU 6: [ 83.844584] netperf R running task 0 8966 8952 0x0000000c [ 83.844587] 0000000000000000 0000000000000006 0000000000006c6c 0000000000000000 [ 83.844589] 000000000000006c 0000000000000096 ffffffff819ce2bc ffffffffffffff10 [ 83.844592] ffffffff81088679 0000000000000010 0000000000000246 ffff880c4b9ddcd8 [ 83.844594] Call Trace: [ 83.844596] [<ffffffff81088679>] ? vprintk_emit+0x1c9/0x4c0 [ 83.844601] [<ffffffff815ad449>] ? schedule+0x29/0x70 [ 83.844606] [<ffffffff81537bd2>] ? tcp_splice_data_recv+0x42/0x50 [ 83.844610] [<ffffffff8153beaa>] ? tcp_read_sock+0xda/0x260 [ 83.844613] [<ffffffff81537b90>] ? tcp_prequeue_process+0xb0/0xb0 [ 83.844615] [<ffffffff8153c0f0>] ? tcp_splice_read+0xc0/0x250 [ 83.844618] [<ffffffff814dc0c2>] ? sock_splice_read+0x22/0x30 [ 83.844622] [<ffffffff811b820b>] ? do_splice_to+0x7b/0xa0 [ 83.844627] [<ffffffff811ba4bc>] ? sys_splice+0x59c/0x5d0 [ 83.844630] [<ffffffff8119745b>] ? putname+0x2b/0x40 [ 83.844633] [<ffffffff8118bcb4>] ? do_sys_open+0x174/0x1e0 [ 83.844636] [<ffffffff815b6202>] ? system_call_fastpath+0x16/0x1b if recv_actor() returns 0, we should stop immediately, because looping wont give a chance to drain the pipe. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-01-10 07:06:10 +00:00
if (used <= 0) {
if (!copied)
copied = used;
break;
} else if (used <= len) {
seq += used;
copied += used;
offset += used;
}
/* If recv_actor drops the lock (e.g. TCP splice
* receive) the skb pointer might be invalid when
* getting here: tcp_collapse might have deleted it
* while aggregating skbs from the socket queue.
*/
skb = tcp_recv_skb(sk, seq - 1, &offset);
if (!skb)
break;
/* TCP coalescing might have appended data to the skb.
* Try to splice more frags
*/
if (offset + 1 != skb->len)
continue;
}
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
sk_eat_skb(sk, skb);
++seq;
break;
}
sk_eat_skb(sk, skb);
if (!desc->count)
break;
tp->copied_seq = seq;
}
tp->copied_seq = seq;
tcp_rcv_space_adjust(sk);
/* Clean up data we have read: This will do ACK frames. */
if (copied > 0) {
tcp_recv_skb(sk, seq, &offset);
tcp_cleanup_rbuf(sk, copied);
}
return copied;
}
EXPORT_SYMBOL(tcp_read_sock);
int tcp_peek_len(struct socket *sock)
{
return tcp_inq(sock->sk);
}
EXPORT_SYMBOL(tcp_peek_len);
/* Make sure sk_rcvbuf is big enough to satisfy SO_RCVLOWAT hint */
int tcp_set_rcvlowat(struct sock *sk, int val)
{
int cap;
if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
cap = sk->sk_rcvbuf >> 1;
else
cap = sock_net(sk)->ipv4.sysctl_tcp_rmem[2] >> 1;
val = min(val, cap);
sk->sk_rcvlowat = val ? : 1;
/* Check if we need to signal EPOLLIN right now */
tcp_data_ready(sk);
if (sk->sk_userlocks & SOCK_RCVBUF_LOCK)
return 0;
val <<= 1;
if (val > sk->sk_rcvbuf) {
sk->sk_rcvbuf = val;
tcp_sk(sk)->window_clamp = tcp_win_from_space(sk, val);
}
return 0;
}
EXPORT_SYMBOL(tcp_set_rcvlowat);
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
#ifdef CONFIG_MMU
static const struct vm_operations_struct tcp_vm_ops = {
};
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
int tcp_mmap(struct file *file, struct socket *sock,
struct vm_area_struct *vma)
{
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
if (vma->vm_flags & (VM_WRITE | VM_EXEC))
return -EPERM;
vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
/* Instruct vm_insert_page() to not down_read(mmap_sem) */
vma->vm_flags |= VM_MIXEDMAP;
vma->vm_ops = &tcp_vm_ops;
return 0;
}
EXPORT_SYMBOL(tcp_mmap);
static int tcp_zerocopy_receive(struct sock *sk,
struct tcp_zerocopy_receive *zc)
{
unsigned long address = (unsigned long)zc->address;
const skb_frag_t *frags = NULL;
u32 length = 0, seq, offset;
struct vm_area_struct *vma;
struct sk_buff *skb = NULL;
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
struct tcp_sock *tp;
int inq;
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
int ret;
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
if (address & (PAGE_SIZE - 1) || address != zc->address)
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
return -EINVAL;
if (sk->sk_state == TCP_LISTEN)
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
return -ENOTCONN;
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
sock_rps_record_flow(sk);
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
down_read(&current->mm->mmap_sem);
ret = -EINVAL;
vma = find_vma(current->mm, address);
if (!vma || vma->vm_start > address || vma->vm_ops != &tcp_vm_ops)
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
goto out;
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
zc->length = min_t(unsigned long, zc->length, vma->vm_end - address);
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
tp = tcp_sk(sk);
seq = tp->copied_seq;
inq = tcp_inq(sk);
zc->length = min_t(u32, zc->length, inq);
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
zc->length &= ~(PAGE_SIZE - 1);
if (zc->length) {
zap_page_range(vma, address, zc->length);
zc->recv_skip_hint = 0;
} else {
zc->recv_skip_hint = inq;
}
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
ret = 0;
while (length + PAGE_SIZE <= zc->length) {
if (zc->recv_skip_hint < PAGE_SIZE) {
if (skb) {
skb = skb->next;
offset = seq - TCP_SKB_CB(skb)->seq;
} else {
skb = tcp_recv_skb(sk, seq, &offset);
}
zc->recv_skip_hint = skb->len - offset;
offset -= skb_headlen(skb);
if ((int)offset < 0 || skb_has_frag_list(skb))
break;
frags = skb_shinfo(skb)->frags;
while (offset) {
if (frags->size > offset)
goto out;
offset -= frags->size;
frags++;
}
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
}
if (frags->size != PAGE_SIZE || frags->page_offset) {
int remaining = zc->recv_skip_hint;
while (remaining && (frags->size != PAGE_SIZE ||
frags->page_offset)) {
remaining -= frags->size;
frags++;
}
zc->recv_skip_hint -= remaining;
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
break;
}
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
ret = vm_insert_page(vma, address + length,
skb_frag_page(frags));
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
if (ret)
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
break;
length += PAGE_SIZE;
seq += PAGE_SIZE;
zc->recv_skip_hint -= PAGE_SIZE;
frags++;
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
}
out:
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
up_read(&current->mm->mmap_sem);
if (length) {
tp->copied_seq = seq;
tcp_rcv_space_adjust(sk);
/* Clean up data we have read: This will do ACK frames. */
tcp_recv_skb(sk, seq, &offset);
tcp_cleanup_rbuf(sk, length);
ret = 0;
if (length == zc->length)
zc->recv_skip_hint = 0;
} else {
if (!zc->recv_skip_hint && sock_flag(sk, SOCK_DONE))
ret = -EIO;
}
zc->length = length;
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
return ret;
}
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
#endif
tcp: implement mmap() for zero copy receive Some networks can make sure TCP payload can exactly fit 4KB pages, with well chosen MSS/MTU and architectures. Implement mmap() system call so that applications can avoid copying data without complex splice() games. Note that a successful mmap( X bytes) on TCP socket is consuming bytes, as if recvmsg() has been done. (tp->copied += X) Only PROT_READ mappings are accepted, as skb page frags are fundamentally shared and read only. If tcp_mmap() finds data that is not a full page, or a patch of urgent data, -EINVAL is returned, no bytes are consumed. Application must fallback to recvmsg() to read the problematic sequence. mmap() wont block, regardless of socket being in blocking or non-blocking mode. If not enough bytes are in receive queue, mmap() would return -EAGAIN, or -EIO if socket is in a state where no other bytes can be added into receive queue. An application might use SO_RCVLOWAT, poll() and/or ioctl( FIONREAD) to efficiently use mmap() On the sender side, MSG_EOR might help to clearly separate unaligned headers and 4K-aligned chunks if necessary. Tested: mlx4 (cx-3) 40Gbit NIC, with tcp_mmap program provided in following patch. MTU set to 4168 (4096 TCP payload, 40 bytes IPv6 header, 32 bytes TCP header) Without mmap() (tcp_mmap -s) received 32768 MB (0 % mmap'ed) in 8.13342 s, 33.7961 Gbit, cpu usage user:0.034 sys:3.778, 116.333 usec per MB, 63062 c-switches received 32768 MB (0 % mmap'ed) in 8.14501 s, 33.748 Gbit, cpu usage user:0.029 sys:3.997, 122.864 usec per MB, 61903 c-switches received 32768 MB (0 % mmap'ed) in 8.11723 s, 33.8635 Gbit, cpu usage user:0.048 sys:3.964, 122.437 usec per MB, 62983 c-switches received 32768 MB (0 % mmap'ed) in 8.39189 s, 32.7552 Gbit, cpu usage user:0.038 sys:4.181, 128.754 usec per MB, 55834 c-switches With mmap() on receiver (tcp_mmap -s -z) received 32768 MB (100 % mmap'ed) in 8.03083 s, 34.2278 Gbit, cpu usage user:0.024 sys:1.466, 45.4712 usec per MB, 65479 c-switches received 32768 MB (100 % mmap'ed) in 7.98805 s, 34.4111 Gbit, cpu usage user:0.026 sys:1.401, 43.5486 usec per MB, 65447 c-switches received 32768 MB (100 % mmap'ed) in 7.98377 s, 34.4296 Gbit, cpu usage user:0.028 sys:1.452, 45.166 usec per MB, 65496 c-switches received 32768 MB (99.9969 % mmap'ed) in 8.01838 s, 34.281 Gbit, cpu usage user:0.02 sys:1.446, 44.7388 usec per MB, 65505 c-switches Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-16 17:33:38 +00:00
static void tcp_update_recv_tstamps(struct sk_buff *skb,
struct scm_timestamping *tss)
{
if (skb->tstamp)
tss->ts[0] = ktime_to_timespec(skb->tstamp);
else
tss->ts[0] = (struct timespec) {0};
if (skb_hwtstamps(skb)->hwtstamp)
tss->ts[2] = ktime_to_timespec(skb_hwtstamps(skb)->hwtstamp);
else
tss->ts[2] = (struct timespec) {0};
}
/* Similar to __sock_recv_timestamp, but does not require an skb */
static void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
struct scm_timestamping *tss)
{
struct timeval tv;
bool has_timestamping = false;
if (tss->ts[0].tv_sec || tss->ts[0].tv_nsec) {
if (sock_flag(sk, SOCK_RCVTSTAMP)) {
if (sock_flag(sk, SOCK_RCVTSTAMPNS)) {
put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPNS,
sizeof(tss->ts[0]), &tss->ts[0]);
} else {
tv.tv_sec = tss->ts[0].tv_sec;
tv.tv_usec = tss->ts[0].tv_nsec / 1000;
put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMP,
sizeof(tv), &tv);
}
}
if (sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE)
has_timestamping = true;
else
tss->ts[0] = (struct timespec) {0};
}
if (tss->ts[2].tv_sec || tss->ts[2].tv_nsec) {
if (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)
has_timestamping = true;
else
tss->ts[2] = (struct timespec) {0};
}
if (has_timestamping) {
tss->ts[1] = (struct timespec) {0};
put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING,
sizeof(*tss), tss);
}
}
tcp: send in-queue bytes in cmsg upon read Applications with many concurrent connections, high variance in receive queue length and tight memory bounds cannot allocate worst-case buffer size to drain sockets. Knowing the size of receive queue length, applications can optimize how they allocate buffers to read from the socket. The number of bytes pending on the socket is directly available through ioctl(FIONREAD/SIOCINQ) and can be approximated using getsockopt(MEMINFO) (rmem_alloc includes skb overheads in addition to application data). But, both of these options add an extra syscall per recvmsg. Moreover, ioctl(FIONREAD/SIOCINQ) takes the socket lock. Add the TCP_INQ socket option to TCP. When this socket option is set, recvmsg() relays the number of bytes available on the socket for reading to the application via the TCP_CM_INQ control message. Calculate the number of bytes after releasing the socket lock to include the processed backlog, if any. To avoid an extra branch in the hot path of recvmsg() for this new control message, move all cmsg processing inside an existing branch for processing receive timestamps. Since the socket lock is not held when calculating the size of receive queue, TCP_INQ is a hint. For example, it can overestimate the queue size by one byte, if FIN is received. With this method, applications can start reading from the socket using a small buffer, and then use larger buffers based on the remaining data when needed. V3 change-log: As suggested by David Miller, added loads with barrier to check whether we have multiple threads calling recvmsg in parallel. When that happens we lock the socket to calculate inq. V4 change-log: Removed inline from a static function. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 19:39:15 +00:00
static int tcp_inq_hint(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
u32 copied_seq = READ_ONCE(tp->copied_seq);
u32 rcv_nxt = READ_ONCE(tp->rcv_nxt);
int inq;
inq = rcv_nxt - copied_seq;
if (unlikely(inq < 0 || copied_seq != READ_ONCE(tp->copied_seq))) {
lock_sock(sk);
inq = tp->rcv_nxt - tp->copied_seq;
release_sock(sk);
}
return inq;
}
/*
* This routine copies from a sock struct into the user buffer.
*
* Technical note: in 2.3 we work on _locked_ socket, so that
* tricks with *seq access order and skb->users are not required.
* Probably, code can be easily improved even more.
*/
int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
int flags, int *addr_len)
{
struct tcp_sock *tp = tcp_sk(sk);
int copied = 0;
u32 peek_seq;
u32 *seq;
unsigned long used;
tcp: send in-queue bytes in cmsg upon read Applications with many concurrent connections, high variance in receive queue length and tight memory bounds cannot allocate worst-case buffer size to drain sockets. Knowing the size of receive queue length, applications can optimize how they allocate buffers to read from the socket. The number of bytes pending on the socket is directly available through ioctl(FIONREAD/SIOCINQ) and can be approximated using getsockopt(MEMINFO) (rmem_alloc includes skb overheads in addition to application data). But, both of these options add an extra syscall per recvmsg. Moreover, ioctl(FIONREAD/SIOCINQ) takes the socket lock. Add the TCP_INQ socket option to TCP. When this socket option is set, recvmsg() relays the number of bytes available on the socket for reading to the application via the TCP_CM_INQ control message. Calculate the number of bytes after releasing the socket lock to include the processed backlog, if any. To avoid an extra branch in the hot path of recvmsg() for this new control message, move all cmsg processing inside an existing branch for processing receive timestamps. Since the socket lock is not held when calculating the size of receive queue, TCP_INQ is a hint. For example, it can overestimate the queue size by one byte, if FIN is received. With this method, applications can start reading from the socket using a small buffer, and then use larger buffers based on the remaining data when needed. V3 change-log: As suggested by David Miller, added loads with barrier to check whether we have multiple threads calling recvmsg in parallel. When that happens we lock the socket to calculate inq. V4 change-log: Removed inline from a static function. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 19:39:15 +00:00
int err, inq;
int target; /* Read at least this many bytes */
long timeo;
struct sk_buff *skb, *last;
u32 urg_hole = 0;
struct scm_timestamping tss;
bool has_tss = false;
tcp: send in-queue bytes in cmsg upon read Applications with many concurrent connections, high variance in receive queue length and tight memory bounds cannot allocate worst-case buffer size to drain sockets. Knowing the size of receive queue length, applications can optimize how they allocate buffers to read from the socket. The number of bytes pending on the socket is directly available through ioctl(FIONREAD/SIOCINQ) and can be approximated using getsockopt(MEMINFO) (rmem_alloc includes skb overheads in addition to application data). But, both of these options add an extra syscall per recvmsg. Moreover, ioctl(FIONREAD/SIOCINQ) takes the socket lock. Add the TCP_INQ socket option to TCP. When this socket option is set, recvmsg() relays the number of bytes available on the socket for reading to the application via the TCP_CM_INQ control message. Calculate the number of bytes after releasing the socket lock to include the processed backlog, if any. To avoid an extra branch in the hot path of recvmsg() for this new control message, move all cmsg processing inside an existing branch for processing receive timestamps. Since the socket lock is not held when calculating the size of receive queue, TCP_INQ is a hint. For example, it can overestimate the queue size by one byte, if FIN is received. With this method, applications can start reading from the socket using a small buffer, and then use larger buffers based on the remaining data when needed. V3 change-log: As suggested by David Miller, added loads with barrier to check whether we have multiple threads calling recvmsg in parallel. When that happens we lock the socket to calculate inq. V4 change-log: Removed inline from a static function. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 19:39:15 +00:00
bool has_cmsg;
net-timestamp: TCP timestamping TCP timestamping extends SO_TIMESTAMPING to bytestreams. Bytestreams do not have a 1:1 relationship between send() buffers and network packets. The feature interprets a send call on a bytestream as a request for a timestamp for the last byte in that send() buffer. The choice corresponds to a request for a timestamp when all bytes in the buffer have been sent. That assumption depends on in-order kernel transmission. This is the common case. That said, it is possible to construct a traffic shaping tree that would result in reordering. The guarantee is strong, then, but not ironclad. This implementation supports send and sendpages (splice). GSO replaces one large packet with multiple smaller packets. This patch also copies the option into the correct smaller packet. This patch does not yet support timestamping on data in an initial TCP Fast Open SYN, because that takes a very different data path. If ID generation in ee_data is enabled, bytestream timestamps return a byte offset, instead of the packet counter for datagrams. The implementation supports a single timestamp per packet. It silenty replaces requests for previous timestamps. To avoid missing tstamps, flush the tcp queue by disabling Nagle, cork and autocork. Missing tstamps can be detected by offset when the ee_data ID is enabled. Implementation details: - On GSO, the timestamping code can be included in the main loop. I moved it into its own loop to reduce the impact on the common case to a single branch. - To avoid leaking the absolute seqno to userspace, the offset returned in ee_data must always be relative. It is an offset between an skb and sk field. The first is always set (also for GSO & ACK). The second must also never be uninitialized. Only allow the ID option on sockets in the ESTABLISHED state, for which the seqno is available. Never reset it to zero (instead, move it to the current seqno when reenabling the option). Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 02:11:49 +00:00
if (unlikely(flags & MSG_ERRQUEUE))
return inet_recv_error(sk, msg, len, addr_len);
net-timestamp: TCP timestamping TCP timestamping extends SO_TIMESTAMPING to bytestreams. Bytestreams do not have a 1:1 relationship between send() buffers and network packets. The feature interprets a send call on a bytestream as a request for a timestamp for the last byte in that send() buffer. The choice corresponds to a request for a timestamp when all bytes in the buffer have been sent. That assumption depends on in-order kernel transmission. This is the common case. That said, it is possible to construct a traffic shaping tree that would result in reordering. The guarantee is strong, then, but not ironclad. This implementation supports send and sendpages (splice). GSO replaces one large packet with multiple smaller packets. This patch also copies the option into the correct smaller packet. This patch does not yet support timestamping on data in an initial TCP Fast Open SYN, because that takes a very different data path. If ID generation in ee_data is enabled, bytestream timestamps return a byte offset, instead of the packet counter for datagrams. The implementation supports a single timestamp per packet. It silenty replaces requests for previous timestamps. To avoid missing tstamps, flush the tcp queue by disabling Nagle, cork and autocork. Missing tstamps can be detected by offset when the ee_data ID is enabled. Implementation details: - On GSO, the timestamping code can be included in the main loop. I moved it into its own loop to reduce the impact on the common case to a single branch. - To avoid leaking the absolute seqno to userspace, the offset returned in ee_data must always be relative. It is an offset between an skb and sk field. The first is always set (also for GSO & ACK). The second must also never be uninitialized. Only allow the ID option on sockets in the ESTABLISHED state, for which the seqno is available. Never reset it to zero (instead, move it to the current seqno when reenabling the option). Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 02:11:49 +00:00
if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&
(sk->sk_state == TCP_ESTABLISHED))
sk_busy_loop(sk, nonblock);
lock_sock(sk);
err = -ENOTCONN;
if (sk->sk_state == TCP_LISTEN)
goto out;
tcp: send in-queue bytes in cmsg upon read Applications with many concurrent connections, high variance in receive queue length and tight memory bounds cannot allocate worst-case buffer size to drain sockets. Knowing the size of receive queue length, applications can optimize how they allocate buffers to read from the socket. The number of bytes pending on the socket is directly available through ioctl(FIONREAD/SIOCINQ) and can be approximated using getsockopt(MEMINFO) (rmem_alloc includes skb overheads in addition to application data). But, both of these options add an extra syscall per recvmsg. Moreover, ioctl(FIONREAD/SIOCINQ) takes the socket lock. Add the TCP_INQ socket option to TCP. When this socket option is set, recvmsg() relays the number of bytes available on the socket for reading to the application via the TCP_CM_INQ control message. Calculate the number of bytes after releasing the socket lock to include the processed backlog, if any. To avoid an extra branch in the hot path of recvmsg() for this new control message, move all cmsg processing inside an existing branch for processing receive timestamps. Since the socket lock is not held when calculating the size of receive queue, TCP_INQ is a hint. For example, it can overestimate the queue size by one byte, if FIN is received. With this method, applications can start reading from the socket using a small buffer, and then use larger buffers based on the remaining data when needed. V3 change-log: As suggested by David Miller, added loads with barrier to check whether we have multiple threads calling recvmsg in parallel. When that happens we lock the socket to calculate inq. V4 change-log: Removed inline from a static function. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 19:39:15 +00:00
has_cmsg = tp->recvmsg_inq;
timeo = sock_rcvtimeo(sk, nonblock);
/* Urgent data needs to be handled specially. */
if (flags & MSG_OOB)
goto recv_urg;
tcp: Repair socket queues Reading queues under repair mode is done with recvmsg call. The queue-under-repair set by TCP_REPAIR_QUEUE option is used to determine which queue should be read. Thus both send and receive queue can be read with this. Caller must pass the MSG_PEEK flag. Writing to queues is done with sendmsg call and yet again -- the repair-queue option can be used to push data into the receive queue. When putting an skb into receive queue a zero tcp header is appented to its head to address the tcp_hdr(skb)->syn and the ->fin checks by the (after repair) tcp_recvmsg. These flags flags are both set to zero and that's why. The fin cannot be met in the queue while reading the source socket, since the repair only works for closed/established sockets and queueing fin packet always changes its state. The syn in the queue denotes that the respective skb's seq is "off-by-one" as compared to the actual payload lenght. Thus, at the rcv queue refill we can just drop this flag and set the skb's sequences to precice values. When the repair mode is turned off, the write queue seqs are updated so that the whole queue is considered to be 'already sent, waiting for ACKs' (write_seq = snd_nxt <= snd_una). From the protocol POV the send queue looks like it was sent, but the data between the write_seq and snd_nxt is lost in the network. This helps to avoid another sockoption for setting the snd_nxt sequence. Leaving the whole queue in a 'not yet sent' state (as it will be after sendmsg-s) will not allow to receive any acks from the peer since the ack_seq will be after the snd_nxt. Thus even the ack for the window probe will be dropped and the connection will be 'locked' with the zero peer window. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-19 03:41:01 +00:00
if (unlikely(tp->repair)) {
err = -EPERM;
if (!(flags & MSG_PEEK))
goto out;
if (tp->repair_queue == TCP_SEND_QUEUE)
goto recv_sndq;
err = -EINVAL;
if (tp->repair_queue == TCP_NO_QUEUE)
goto out;
/* 'common' recv queue MSG_PEEK-ing */
}
seq = &tp->copied_seq;
if (flags & MSG_PEEK) {
peek_seq = tp->copied_seq;
seq = &peek_seq;
}
target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
do {
u32 offset;
/* Are we at urgent data? Stop if we have read anything or have SIGURG pending. */
if (tp->urg_data && tp->urg_seq == *seq) {
if (copied)
break;
if (signal_pending(current)) {
copied = timeo ? sock_intr_errno(timeo) : -EAGAIN;
break;
}
}
/* Next get a buffer. */
last = skb_peek_tail(&sk->sk_receive_queue);
skb_queue_walk(&sk->sk_receive_queue, skb) {
last = skb;
/* Now that we have two receive queues this
* shouldn't happen.
*/
if (WARN(before(*seq, TCP_SKB_CB(skb)->seq),
"TCP recvmsg seq # bug: copied %X, seq %X, rcvnxt %X, fl %X\n",
*seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt,
flags))
break;
offset = *seq - TCP_SKB_CB(skb)->seq;
if (unlikely(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
pr_err_once("%s: found a SYN, please report !\n", __func__);
offset--;
}
if (offset < skb->len)
goto found_ok_skb;
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
goto found_fin_ok;
WARN(!(flags & MSG_PEEK),
"TCP recvmsg seq # bug 2: copied %X, seq %X, rcvnxt %X, fl %X\n",
*seq, TCP_SKB_CB(skb)->seq, tp->rcv_nxt, flags);
}
/* Well, if we have backlog, try to process it now yet. */
if (copied >= target && !sk->sk_backlog.tail)
break;
if (copied) {
if (sk->sk_err ||
sk->sk_state == TCP_CLOSE ||
(sk->sk_shutdown & RCV_SHUTDOWN) ||
!timeo ||
signal_pending(current))
break;
} else {
if (sock_flag(sk, SOCK_DONE))
break;
if (sk->sk_err) {
copied = sock_error(sk);
break;
}
if (sk->sk_shutdown & RCV_SHUTDOWN)
break;
if (sk->sk_state == TCP_CLOSE) {
/* This occurs when user tries to read
* from never connected socket.
*/
copied = -ENOTCONN;
break;
}
if (!timeo) {
copied = -EAGAIN;
break;
}
if (signal_pending(current)) {
copied = sock_intr_errno(timeo);
break;
}
}
tcp_cleanup_rbuf(sk, copied);
if (copied >= target) {
/* Do not sleep, just process backlog. */
release_sock(sk);
lock_sock(sk);
} else {
sk_wait_data(sk, &timeo, last);
}
if ((flags & MSG_PEEK) &&
(peek_seq - copied - urg_hole != tp->copied_seq)) {
net_dbg_ratelimited("TCP(%s:%d): Application bug, race in MSG_PEEK\n",
current->comm,
task_pid_nr(current));
peek_seq = tp->copied_seq;
}
continue;
found_ok_skb:
/* Ok so how much can we use? */
used = skb->len - offset;
if (len < used)
used = len;
/* Do we have urgent data here? */
if (tp->urg_data) {
u32 urg_offset = tp->urg_seq - *seq;
if (urg_offset < used) {
if (!urg_offset) {
if (!sock_flag(sk, SOCK_URGINLINE)) {
++*seq;
urg_hole++;
offset++;
used--;
if (!used)
goto skip_copy;
}
} else
used = urg_offset;
}
}
if (!(flags & MSG_TRUNC)) {
err = skb_copy_datagram_msg(skb, offset, msg, used);
if (err) {
/* Exception. Bailout! */
if (!copied)
copied = -EFAULT;
break;
}
}
*seq += used;
copied += used;
len -= used;
tcp_rcv_space_adjust(sk);
skip_copy:
if (tp->urg_data && after(tp->copied_seq, tp->urg_seq)) {
tp->urg_data = 0;
tcp_fast_path_check(sk);
}
if (used + offset < skb->len)
continue;
if (TCP_SKB_CB(skb)->has_rxtstamp) {
tcp_update_recv_tstamps(skb, &tss);
has_tss = true;
tcp: send in-queue bytes in cmsg upon read Applications with many concurrent connections, high variance in receive queue length and tight memory bounds cannot allocate worst-case buffer size to drain sockets. Knowing the size of receive queue length, applications can optimize how they allocate buffers to read from the socket. The number of bytes pending on the socket is directly available through ioctl(FIONREAD/SIOCINQ) and can be approximated using getsockopt(MEMINFO) (rmem_alloc includes skb overheads in addition to application data). But, both of these options add an extra syscall per recvmsg. Moreover, ioctl(FIONREAD/SIOCINQ) takes the socket lock. Add the TCP_INQ socket option to TCP. When this socket option is set, recvmsg() relays the number of bytes available on the socket for reading to the application via the TCP_CM_INQ control message. Calculate the number of bytes after releasing the socket lock to include the processed backlog, if any. To avoid an extra branch in the hot path of recvmsg() for this new control message, move all cmsg processing inside an existing branch for processing receive timestamps. Since the socket lock is not held when calculating the size of receive queue, TCP_INQ is a hint. For example, it can overestimate the queue size by one byte, if FIN is received. With this method, applications can start reading from the socket using a small buffer, and then use larger buffers based on the remaining data when needed. V3 change-log: As suggested by David Miller, added loads with barrier to check whether we have multiple threads calling recvmsg in parallel. When that happens we lock the socket to calculate inq. V4 change-log: Removed inline from a static function. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 19:39:15 +00:00
has_cmsg = true;
}
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
goto found_fin_ok;
if (!(flags & MSG_PEEK))
sk_eat_skb(sk, skb);
continue;
found_fin_ok:
/* Process the FIN. */
++*seq;
if (!(flags & MSG_PEEK))
sk_eat_skb(sk, skb);
break;
} while (len > 0);
/* According to UNIX98, msg_name/msg_namelen are ignored
* on connected socket. I was just happy when found this 8) --ANK
*/
/* Clean up data we have read: This will do ACK frames. */
tcp_cleanup_rbuf(sk, copied);
release_sock(sk);
tcp: send in-queue bytes in cmsg upon read Applications with many concurrent connections, high variance in receive queue length and tight memory bounds cannot allocate worst-case buffer size to drain sockets. Knowing the size of receive queue length, applications can optimize how they allocate buffers to read from the socket. The number of bytes pending on the socket is directly available through ioctl(FIONREAD/SIOCINQ) and can be approximated using getsockopt(MEMINFO) (rmem_alloc includes skb overheads in addition to application data). But, both of these options add an extra syscall per recvmsg. Moreover, ioctl(FIONREAD/SIOCINQ) takes the socket lock. Add the TCP_INQ socket option to TCP. When this socket option is set, recvmsg() relays the number of bytes available on the socket for reading to the application via the TCP_CM_INQ control message. Calculate the number of bytes after releasing the socket lock to include the processed backlog, if any. To avoid an extra branch in the hot path of recvmsg() for this new control message, move all cmsg processing inside an existing branch for processing receive timestamps. Since the socket lock is not held when calculating the size of receive queue, TCP_INQ is a hint. For example, it can overestimate the queue size by one byte, if FIN is received. With this method, applications can start reading from the socket using a small buffer, and then use larger buffers based on the remaining data when needed. V3 change-log: As suggested by David Miller, added loads with barrier to check whether we have multiple threads calling recvmsg in parallel. When that happens we lock the socket to calculate inq. V4 change-log: Removed inline from a static function. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 19:39:15 +00:00
if (has_cmsg) {
if (has_tss)
tcp_recv_timestamp(msg, sk, &tss);
if (tp->recvmsg_inq) {
inq = tcp_inq_hint(sk);
put_cmsg(msg, SOL_TCP, TCP_CM_INQ, sizeof(inq), &inq);
}
}
return copied;
out:
release_sock(sk);
return err;
recv_urg:
err = tcp_recv_urg(sk, msg, len, flags);
goto out;
tcp: Repair socket queues Reading queues under repair mode is done with recvmsg call. The queue-under-repair set by TCP_REPAIR_QUEUE option is used to determine which queue should be read. Thus both send and receive queue can be read with this. Caller must pass the MSG_PEEK flag. Writing to queues is done with sendmsg call and yet again -- the repair-queue option can be used to push data into the receive queue. When putting an skb into receive queue a zero tcp header is appented to its head to address the tcp_hdr(skb)->syn and the ->fin checks by the (after repair) tcp_recvmsg. These flags flags are both set to zero and that's why. The fin cannot be met in the queue while reading the source socket, since the repair only works for closed/established sockets and queueing fin packet always changes its state. The syn in the queue denotes that the respective skb's seq is "off-by-one" as compared to the actual payload lenght. Thus, at the rcv queue refill we can just drop this flag and set the skb's sequences to precice values. When the repair mode is turned off, the write queue seqs are updated so that the whole queue is considered to be 'already sent, waiting for ACKs' (write_seq = snd_nxt <= snd_una). From the protocol POV the send queue looks like it was sent, but the data between the write_seq and snd_nxt is lost in the network. This helps to avoid another sockoption for setting the snd_nxt sequence. Leaving the whole queue in a 'not yet sent' state (as it will be after sendmsg-s) will not allow to receive any acks from the peer since the ack_seq will be after the snd_nxt. Thus even the ack for the window probe will be dropped and the connection will be 'locked' with the zero peer window. Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-19 03:41:01 +00:00
recv_sndq:
err = tcp_peek_sndq(sk, msg, len);
goto out;
}
EXPORT_SYMBOL(tcp_recvmsg);
void tcp_set_state(struct sock *sk, int state)
{
int oldstate = sk->sk_state;
/* We defined a new enum for TCP states that are exported in BPF
* so as not force the internal TCP states to be frozen. The
* following checks will detect if an internal state value ever
* differs from the BPF value. If this ever happens, then we will
* need to remap the internal value to the BPF value before calling
* tcp_call_bpf_2arg.
*/
BUILD_BUG_ON((int)BPF_TCP_ESTABLISHED != (int)TCP_ESTABLISHED);
BUILD_BUG_ON((int)BPF_TCP_SYN_SENT != (int)TCP_SYN_SENT);
BUILD_BUG_ON((int)BPF_TCP_SYN_RECV != (int)TCP_SYN_RECV);
BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT1 != (int)TCP_FIN_WAIT1);
BUILD_BUG_ON((int)BPF_TCP_FIN_WAIT2 != (int)TCP_FIN_WAIT2);
BUILD_BUG_ON((int)BPF_TCP_TIME_WAIT != (int)TCP_TIME_WAIT);
BUILD_BUG_ON((int)BPF_TCP_CLOSE != (int)TCP_CLOSE);
BUILD_BUG_ON((int)BPF_TCP_CLOSE_WAIT != (int)TCP_CLOSE_WAIT);
BUILD_BUG_ON((int)BPF_TCP_LAST_ACK != (int)TCP_LAST_ACK);
BUILD_BUG_ON((int)BPF_TCP_LISTEN != (int)TCP_LISTEN);
BUILD_BUG_ON((int)BPF_TCP_CLOSING != (int)TCP_CLOSING);
BUILD_BUG_ON((int)BPF_TCP_NEW_SYN_RECV != (int)TCP_NEW_SYN_RECV);
BUILD_BUG_ON((int)BPF_TCP_MAX_STATES != (int)TCP_MAX_STATES);
if (BPF_SOCK_OPS_TEST_FLAG(tcp_sk(sk), BPF_SOCK_OPS_STATE_CB_FLAG))
tcp_call_bpf_2arg(sk, BPF_SOCK_OPS_STATE_CB, oldstate, state);
switch (state) {
case TCP_ESTABLISHED:
if (oldstate != TCP_ESTABLISHED)
TCP_INC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
break;
case TCP_CLOSE:
if (oldstate == TCP_CLOSE_WAIT || oldstate == TCP_ESTABLISHED)
TCP_INC_STATS(sock_net(sk), TCP_MIB_ESTABRESETS);
sk->sk_prot->unhash(sk);
if (inet_csk(sk)->icsk_bind_hash &&
!(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
[SOCK] proto: Add hashinfo member to struct proto This way we can remove TCP and DCCP specific versions of sk->sk_prot->get_port: both v4 and v6 use inet_csk_get_port sk->sk_prot->hash: inet_hash is directly used, only v6 need a specific version to deal with mapped sockets sk->sk_prot->unhash: both v4 and v6 use inet_hash directly struct inet_connection_sock_af_ops also gets a new member, bind_conflict, so that inet_csk_get_port can find the per family routine. Now only the lookup routines receive as a parameter a struct inet_hashtable. With this we further reuse code, reducing the difference among INET transport protocols. Eventually work has to be done on UDP and SCTP to make them share this infrastructure and get as a bonus inet_diag interfaces so that iproute can be used with these protocols. net-2.6/net/ipv4/inet_hashtables.c: struct proto | +8 struct inet_connection_sock_af_ops | +8 2 structs changed __inet_hash_nolisten | +18 __inet_hash | -210 inet_put_port | +8 inet_bind_bucket_create | +1 __inet_hash_connect | -8 5 functions changed, 27 bytes added, 218 bytes removed, diff: -191 net-2.6/net/core/sock.c: proto_seq_show | +3 1 function changed, 3 bytes added, diff: +3 net-2.6/net/ipv4/inet_connection_sock.c: inet_csk_get_port | +15 1 function changed, 15 bytes added, diff: +15 net-2.6/net/ipv4/tcp.c: tcp_set_state | -7 1 function changed, 7 bytes removed, diff: -7 net-2.6/net/ipv4/tcp_ipv4.c: tcp_v4_get_port | -31 tcp_v4_hash | -48 tcp_v4_destroy_sock | -7 tcp_v4_syn_recv_sock | -2 tcp_unhash | -179 5 functions changed, 267 bytes removed, diff: -267 net-2.6/net/ipv6/inet6_hashtables.c: __inet6_hash | +8 1 function changed, 8 bytes added, diff: +8 net-2.6/net/ipv4/inet_hashtables.c: inet_unhash | +190 inet_hash | +242 2 functions changed, 432 bytes added, diff: +432 vmlinux: 16 functions changed, 485 bytes added, 492 bytes removed, diff: -7 /home/acme/git/net-2.6/net/ipv6/tcp_ipv6.c: tcp_v6_get_port | -31 tcp_v6_hash | -7 tcp_v6_syn_recv_sock | -9 3 functions changed, 47 bytes removed, diff: -47 /home/acme/git/net-2.6/net/dccp/proto.c: dccp_destroy_sock | -7 dccp_unhash | -179 dccp_hash | -49 dccp_set_state | -7 dccp_done | +1 5 functions changed, 1 bytes added, 242 bytes removed, diff: -241 /home/acme/git/net-2.6/net/dccp/ipv4.c: dccp_v4_get_port | -31 dccp_v4_request_recv_sock | -2 2 functions changed, 33 bytes removed, diff: -33 /home/acme/git/net-2.6/net/dccp/ipv6.c: dccp_v6_get_port | -31 dccp_v6_hash | -7 dccp_v6_request_recv_sock | +5 3 functions changed, 5 bytes added, 38 bytes removed, diff: -33 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-02-03 12:06:04 +00:00
inet_put_port(sk);
/* fall through */
default:
if (oldstate == TCP_ESTABLISHED)
TCP_DEC_STATS(sock_net(sk), TCP_MIB_CURRESTAB);
}
/* Change state AFTER socket is unhashed to avoid closed
* socket sitting in hash tables.
*/
inet_sk_state_store(sk, state);
}
EXPORT_SYMBOL_GPL(tcp_set_state);
/*
* State processing on a close. This implements the state shift for
* sending our FIN frame. Note that we only send a FIN for some
* states. A shutdown() may have already sent the FIN, or we may be
* closed.
*/
static const unsigned char new_state[16] = {
/* current state: new state: action: */
[0 /* (Invalid) */] = TCP_CLOSE,
[TCP_ESTABLISHED] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
[TCP_SYN_SENT] = TCP_CLOSE,
[TCP_SYN_RECV] = TCP_FIN_WAIT1 | TCP_ACTION_FIN,
[TCP_FIN_WAIT1] = TCP_FIN_WAIT1,
[TCP_FIN_WAIT2] = TCP_FIN_WAIT2,
[TCP_TIME_WAIT] = TCP_CLOSE,
[TCP_CLOSE] = TCP_CLOSE,
[TCP_CLOSE_WAIT] = TCP_LAST_ACK | TCP_ACTION_FIN,
[TCP_LAST_ACK] = TCP_LAST_ACK,
[TCP_LISTEN] = TCP_CLOSE,
[TCP_CLOSING] = TCP_CLOSING,
[TCP_NEW_SYN_RECV] = TCP_CLOSE, /* should not happen ! */
};
static int tcp_close_state(struct sock *sk)
{
int next = (int)new_state[sk->sk_state];
int ns = next & TCP_STATE_MASK;
tcp_set_state(sk, ns);
return next & TCP_ACTION_FIN;
}
/*
* Shutdown the sending side of a connection. Much like close except
* that we don't receive shut down or sock_set_flag(sk, SOCK_DEAD).
*/
void tcp_shutdown(struct sock *sk, int how)
{
/* We need to grab some memory, and put together a FIN,
* and then put it into the queue to be sent.
* Tim MacKenzie(tym@dibbler.cs.monash.edu.au) 4 Dec '92.
*/
if (!(how & SEND_SHUTDOWN))
return;
/* If we've already sent a FIN, or it's a closed state, skip this. */
if ((1 << sk->sk_state) &
(TCPF_ESTABLISHED | TCPF_SYN_SENT |
TCPF_SYN_RECV | TCPF_CLOSE_WAIT)) {
/* Clear out any half completed packets. FIN if needed. */
if (tcp_close_state(sk))
tcp_send_fin(sk);
}
}
EXPORT_SYMBOL(tcp_shutdown);
bool tcp_check_oom(struct sock *sk, int shift)
{
bool too_many_orphans, out_of_socket_memory;
too_many_orphans = tcp_too_many_orphans(sk, shift);
out_of_socket_memory = tcp_out_of_memory(sk);
if (too_many_orphans)
net_info_ratelimited("too many orphaned sockets\n");
if (out_of_socket_memory)
net_info_ratelimited("out of memory -- consider tuning tcp_mem\n");
return too_many_orphans || out_of_socket_memory;
}
void tcp_close(struct sock *sk, long timeout)
{
struct sk_buff *skb;
int data_was_unread = 0;
[TCP]: Fix sock_orphan dead lock Calling sock_orphan inside bh_lock_sock in tcp_close can lead to dead locks. For example, the inet_diag code holds sk_callback_lock without disabling BH. If an inbound packet arrives during that admittedly tiny window, it will cause a dead lock on bh_lock_sock. Another possible path would be through sock_wfree if the network device driver frees the tx skb in process context with BH enabled. We can fix this by moving sock_orphan out of bh_lock_sock. The tricky bit is to work out when we need to destroy the socket ourselves and when it has already been destroyed by someone else. By moving sock_orphan before the release_sock we can solve this problem. This is because as long as we own the socket lock its state cannot change. So we simply record the socket state before the release_sock and then check the state again after we regain the socket lock. If the socket state has transitioned to TCP_CLOSE in the time being, we know that the socket has been destroyed. Otherwise the socket is still ours to keep. Note that I've also moved the increment on the orphan count forward. This may look like a problem as we're increasing it even if the socket is just about to be destroyed where it'll be decreased again. However, this simply enlarges a window that already exists. This also changes the orphan count test by one. Considering what the orphan count is meant to do this is no big deal. This problem was discoverd by Ingo Molnar using his lock validator. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-05-04 06:31:35 +00:00
int state;
lock_sock(sk);
sk->sk_shutdown = SHUTDOWN_MASK;
if (sk->sk_state == TCP_LISTEN) {
tcp_set_state(sk, TCP_CLOSE);
/* Special case. */
inet_csk_listen_stop(sk);
goto adjudge_to_death;
}
/* We need to flush the recv. buffs. We do this only on the
* descriptor close, not protocol-sourced closes, because the
* reader process may not have drained the data yet!
*/
while ((skb = __skb_dequeue(&sk->sk_receive_queue)) != NULL) {
u32 len = TCP_SKB_CB(skb)->end_seq - TCP_SKB_CB(skb)->seq;
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
len--;
data_was_unread += len;
__kfree_skb(skb);
}
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 08:11:19 +00:00
sk_mem_reclaim(sk);
tcp: do not send reset to already closed sockets i've found that tcp_close() can be called for an already closed socket, but still sends reset in this case (tcp_send_active_reset()) which seems to be incorrect. Moreover, a packet with reset is sent with different source port as original port number has been already cleared on socket. Besides that incrementing stat counter for LINUX_MIB_TCPABORTONCLOSE also does not look correct in this case. Initially this issue was found on 2.6.18-x RHEL5 kernel, but the same seems to be true for the current mainstream kernel (checked on 2.6.35-rc3). Please, correct me if i missed something. How that happens: 1) the server receives a packet for socket in TCP_CLOSE_WAIT state that triggers a tcp_reset(): Call Trace: <IRQ> [<ffffffff8025b9b9>] tcp_reset+0x12f/0x1e8 [<ffffffff80046125>] tcp_rcv_state_process+0x1c0/0xa08 [<ffffffff8003eb22>] tcp_v4_do_rcv+0x310/0x37a [<ffffffff80028bea>] tcp_v4_rcv+0x74d/0xb43 [<ffffffff8024ef4c>] ip_local_deliver_finish+0x0/0x259 [<ffffffff80037131>] ip_local_deliver+0x200/0x2f4 [<ffffffff8003843c>] ip_rcv+0x64c/0x69f [<ffffffff80021d89>] netif_receive_skb+0x4c4/0x4fa [<ffffffff80032eca>] process_backlog+0x90/0xec [<ffffffff8000cc50>] net_rx_action+0xbb/0x1f1 [<ffffffff80012d3a>] __do_softirq+0xf5/0x1ce [<ffffffff8001147a>] handle_IRQ_event+0x56/0xb0 [<ffffffff8006334c>] call_softirq+0x1c/0x28 [<ffffffff80070476>] do_softirq+0x2c/0x85 [<ffffffff80070441>] do_IRQ+0x149/0x152 [<ffffffff80062665>] ret_from_intr+0x0/0xa <EOI> [<ffffffff80008a2e>] __handle_mm_fault+0x6cd/0x1303 [<ffffffff80008903>] __handle_mm_fault+0x5a2/0x1303 [<ffffffff80033a9d>] cache_free_debugcheck+0x21f/0x22e [<ffffffff8006a263>] do_page_fault+0x49a/0x7dc [<ffffffff80066487>] thread_return+0x89/0x174 [<ffffffff800c5aee>] audit_syscall_exit+0x341/0x35c [<ffffffff80062e39>] error_exit+0x0/0x84 tcp_rcv_state_process() ... // (sk_state == TCP_CLOSE_WAIT here) ... /* step 2: check RST bit */ if(th->rst) { tcp_reset(sk); goto discard; } ... --------------------------------- tcp_rcv_state_process tcp_reset tcp_done tcp_set_state(sk, TCP_CLOSE); inet_put_port __inet_put_port inet_sk(sk)->num = 0; sk->sk_shutdown = SHUTDOWN_MASK; 2) After that the process (socket owner) tries to write something to that socket and "inet_autobind" sets a _new_ (which differs from the original!) port number for the socket: Call Trace: [<ffffffff80255a12>] inet_bind_hash+0x33/0x5f [<ffffffff80257180>] inet_csk_get_port+0x216/0x268 [<ffffffff8026bcc9>] inet_autobind+0x22/0x8f [<ffffffff80049140>] inet_sendmsg+0x27/0x57 [<ffffffff8003a9d9>] do_sock_write+0xae/0xea [<ffffffff80226ac7>] sock_writev+0xdc/0xf6 [<ffffffff800680c7>] _spin_lock_irqsave+0x9/0xe [<ffffffff8001fb49>] __pollwait+0x0/0xdd [<ffffffff8008d533>] default_wake_function+0x0/0xe [<ffffffff800a4f10>] autoremove_wake_function+0x0/0x2e [<ffffffff800f0b49>] do_readv_writev+0x163/0x274 [<ffffffff80066538>] thread_return+0x13a/0x174 [<ffffffff800145d8>] tcp_poll+0x0/0x1c9 [<ffffffff800c56d3>] audit_syscall_entry+0x180/0x1b3 [<ffffffff800f0dd0>] sys_writev+0x49/0xe4 [<ffffffff800622dd>] tracesys+0xd5/0xe0 3) sendmsg fails at last with -EPIPE (=> 'write' returns -EPIPE in userspace): F: tcp_sendmsg1 -EPIPE: sk=ffff81000bda00d0, sport=49847, old_state=7, new_state=7, sk_err=0, sk_shutdown=3 Call Trace: [<ffffffff80027557>] tcp_sendmsg+0xcb/0xe87 [<ffffffff80033300>] release_sock+0x10/0xae [<ffffffff8016f20f>] vgacon_cursor+0x0/0x1a7 [<ffffffff8026bd32>] inet_autobind+0x8b/0x8f [<ffffffff8003a9d9>] do_sock_write+0xae/0xea [<ffffffff80226ac7>] sock_writev+0xdc/0xf6 [<ffffffff800680c7>] _spin_lock_irqsave+0x9/0xe [<ffffffff8001fb49>] __pollwait+0x0/0xdd [<ffffffff8008d533>] default_wake_function+0x0/0xe [<ffffffff800a4f10>] autoremove_wake_function+0x0/0x2e [<ffffffff800f0b49>] do_readv_writev+0x163/0x274 [<ffffffff80066538>] thread_return+0x13a/0x174 [<ffffffff800145d8>] tcp_poll+0x0/0x1c9 [<ffffffff800c56d3>] audit_syscall_entry+0x180/0x1b3 [<ffffffff800f0dd0>] sys_writev+0x49/0xe4 [<ffffffff800622dd>] tracesys+0xd5/0xe0 tcp_sendmsg() ... /* Wait for a connection to finish. */ if ((1 << sk->sk_state) & ~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) { int old_state = sk->sk_state; if ((err = sk_stream_wait_connect(sk, &timeo)) != 0) { if (f_d && (err == -EPIPE)) { printk("F: tcp_sendmsg1 -EPIPE: sk=%p, sport=%u, old_state=%d, new_state=%d, " "sk_err=%d, sk_shutdown=%d\n", sk, ntohs(inet_sk(sk)->sport), old_state, sk->sk_state, sk->sk_err, sk->sk_shutdown); dump_stack(); } goto out_err; } } ... 4) Then the process (socket owner) understands that it's time to close that socket and does that (and thus triggers sending reset packet): Call Trace: ... [<ffffffff80032077>] dev_queue_xmit+0x343/0x3d6 [<ffffffff80034698>] ip_output+0x351/0x384 [<ffffffff80251ae9>] dst_output+0x0/0xe [<ffffffff80036ec6>] ip_queue_xmit+0x567/0x5d2 [<ffffffff80095700>] vprintk+0x21/0x33 [<ffffffff800070f0>] check_poison_obj+0x2e/0x206 [<ffffffff80013587>] poison_obj+0x36/0x45 [<ffffffff8025dea6>] tcp_send_active_reset+0x15/0x14d [<ffffffff80023481>] dbg_redzone1+0x1c/0x25 [<ffffffff8025dea6>] tcp_send_active_reset+0x15/0x14d [<ffffffff8000ca94>] cache_alloc_debugcheck_after+0x189/0x1c8 [<ffffffff80023405>] tcp_transmit_skb+0x764/0x786 [<ffffffff8025df8a>] tcp_send_active_reset+0xf9/0x14d [<ffffffff80258ff1>] tcp_close+0x39a/0x960 [<ffffffff8026be12>] inet_release+0x69/0x80 [<ffffffff80059b31>] sock_release+0x4f/0xcf [<ffffffff80059d4c>] sock_close+0x2c/0x30 [<ffffffff800133c9>] __fput+0xac/0x197 [<ffffffff800252bc>] filp_close+0x59/0x61 [<ffffffff8001eff6>] sys_close+0x85/0xc7 [<ffffffff800622dd>] tracesys+0xd5/0xe0 So, in brief: * a received packet for socket in TCP_CLOSE_WAIT state triggers tcp_reset() which clears inet_sk(sk)->num and put socket into TCP_CLOSE state * an attempt to write to that socket forces inet_autobind() to get a new port (but the write itself fails with -EPIPE) * tcp_close() called for socket in TCP_CLOSE state sends an active reset via socket with newly allocated port This adds an additional check in tcp_close() for already closed sockets. We do not want to send anything to closed sockets. Signed-off-by: Konstantin Khorenko <khorenko@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-06-25 04:54:58 +00:00
/* If socket has been already reset (e.g. in tcp_reset()) - kill it. */
if (sk->sk_state == TCP_CLOSE)
goto adjudge_to_death;
/* As outlined in RFC 2525, section 2.17, we send a RST here because
* data was lost. To witness the awful effects of the old behavior of
* always doing a FIN, run an older 2.1.x kernel or 2.0.x, start a bulk
* GET in an FTP client, suspend the process, wait for the client to
* advertise a zero window, then kill -9 the FTP client, wheee...
* Note: timeout is always zero in such a case.
*/
if (unlikely(tcp_sk(sk)->repair)) {
sk->sk_prot->disconnect(sk, 0);
} else if (data_was_unread) {
/* Unread data was tossed, zap the connection. */
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONCLOSE);
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, sk->sk_allocation);
} else if (sock_flag(sk, SOCK_LINGER) && !sk->sk_lingertime) {
/* Check zero linger _after_ checking for unread data. */
sk->sk_prot->disconnect(sk, 0);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPABORTONDATA);
} else if (tcp_close_state(sk)) {
/* We FIN if the application ate all the data before
* zapping the connection.
*/
/* RED-PEN. Formally speaking, we have broken TCP state
* machine. State transitions:
*
* TCP_ESTABLISHED -> TCP_FIN_WAIT1
* TCP_SYN_RECV -> TCP_FIN_WAIT1 (forget it, it's impossible)
* TCP_CLOSE_WAIT -> TCP_LAST_ACK
*
* are legal only when FIN has been sent (i.e. in window),
* rather than queued out of window. Purists blame.
*
* F.e. "RFC state" is ESTABLISHED,
* if Linux state is FIN-WAIT-1, but FIN is still not sent.
*
* The visible declinations are that sometimes
* we enter time-wait state, when it is not required really
* (harmless), do not send active resets, when they are
* required by specs (TCP_ESTABLISHED, TCP_CLOSE_WAIT, when
* they look as CLOSING or LAST_ACK for Linux)
* Probably, I missed some more holelets.
* --ANK
* XXX (TFO) - To start off we don't support SYN+ACK+FIN
* in a single packet! (May consider it later but will
* probably need API support or TCP_CORK SYN-ACK until
* data is written and socket is closed.)
*/
tcp_send_fin(sk);
}
sk_stream_wait_close(sk, timeout);
adjudge_to_death:
[TCP]: Fix sock_orphan dead lock Calling sock_orphan inside bh_lock_sock in tcp_close can lead to dead locks. For example, the inet_diag code holds sk_callback_lock without disabling BH. If an inbound packet arrives during that admittedly tiny window, it will cause a dead lock on bh_lock_sock. Another possible path would be through sock_wfree if the network device driver frees the tx skb in process context with BH enabled. We can fix this by moving sock_orphan out of bh_lock_sock. The tricky bit is to work out when we need to destroy the socket ourselves and when it has already been destroyed by someone else. By moving sock_orphan before the release_sock we can solve this problem. This is because as long as we own the socket lock its state cannot change. So we simply record the socket state before the release_sock and then check the state again after we regain the socket lock. If the socket state has transitioned to TCP_CLOSE in the time being, we know that the socket has been destroyed. Otherwise the socket is still ours to keep. Note that I've also moved the increment on the orphan count forward. This may look like a problem as we're increasing it even if the socket is just about to be destroyed where it'll be decreased again. However, this simply enlarges a window that already exists. This also changes the orphan count test by one. Considering what the orphan count is meant to do this is no big deal. This problem was discoverd by Ingo Molnar using his lock validator. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-05-04 06:31:35 +00:00
state = sk->sk_state;
sock_hold(sk);
sock_orphan(sk);
local_bh_disable();
bh_lock_sock(sk);
/* remove backlog if any, without releasing ownership. */
__release_sock(sk);
percpu_counter_inc(sk->sk_prot->orphan_count);
[TCP]: Fix sock_orphan dead lock Calling sock_orphan inside bh_lock_sock in tcp_close can lead to dead locks. For example, the inet_diag code holds sk_callback_lock without disabling BH. If an inbound packet arrives during that admittedly tiny window, it will cause a dead lock on bh_lock_sock. Another possible path would be through sock_wfree if the network device driver frees the tx skb in process context with BH enabled. We can fix this by moving sock_orphan out of bh_lock_sock. The tricky bit is to work out when we need to destroy the socket ourselves and when it has already been destroyed by someone else. By moving sock_orphan before the release_sock we can solve this problem. This is because as long as we own the socket lock its state cannot change. So we simply record the socket state before the release_sock and then check the state again after we regain the socket lock. If the socket state has transitioned to TCP_CLOSE in the time being, we know that the socket has been destroyed. Otherwise the socket is still ours to keep. Note that I've also moved the increment on the orphan count forward. This may look like a problem as we're increasing it even if the socket is just about to be destroyed where it'll be decreased again. However, this simply enlarges a window that already exists. This also changes the orphan count test by one. Considering what the orphan count is meant to do this is no big deal. This problem was discoverd by Ingo Molnar using his lock validator. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-05-04 06:31:35 +00:00
/* Have we already been destroyed by a softirq or backlog? */
if (state != TCP_CLOSE && sk->sk_state == TCP_CLOSE)
goto out;
/* This is a (useful) BSD violating of the RFC. There is a
* problem with TCP as specified in that the other end could
* keep a socket open forever with no application left this end.
* We use a 1 minute timeout (about the same as BSD) then kill
* our end. If they send after that then tough - BUT: long enough
* that we won't make the old 4*rto = almost no time - whoops
* reset mistake.
*
* Nope, it was not mistake. It is really desired behaviour
* f.e. on http servers, when such sockets are useless, but
* consume significant resources. Let's do it with special
* linger2 option. --ANK
*/
if (sk->sk_state == TCP_FIN_WAIT2) {
struct tcp_sock *tp = tcp_sk(sk);
if (tp->linger2 < 0) {
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, GFP_ATOMIC);
__NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPABORTONLINGER);
} else {
const int tmo = tcp_fin_time(sk);
if (tmo > TCP_TIMEWAIT_LEN) {
inet_csk_reset_keepalive_timer(sk,
tmo - TCP_TIMEWAIT_LEN);
} else {
tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
goto out;
}
}
}
if (sk->sk_state != TCP_CLOSE) {
[NET] CORE: Introducing new memory accounting interface. This patch introduces new memory accounting functions for each network protocol. Most of them are renamed from memory accounting functions for stream protocols. At the same time, some stream memory accounting functions are removed since other functions do same thing. Renaming: sk_stream_free_skb() -> sk_wmem_free_skb() __sk_stream_mem_reclaim() -> __sk_mem_reclaim() sk_stream_mem_reclaim() -> sk_mem_reclaim() sk_stream_mem_schedule -> __sk_mem_schedule() sk_stream_pages() -> sk_mem_pages() sk_stream_rmem_schedule() -> sk_rmem_schedule() sk_stream_wmem_schedule() -> sk_wmem_schedule() sk_charge_skb() -> sk_mem_charge() Removeing sk_stream_rfree(): consolidates into sock_rfree() sk_stream_set_owner_r(): consolidates into skb_set_owner_r() sk_stream_mem_schedule() The following functions are added. sk_has_account(): check if the protocol supports accounting sk_mem_uncharge(): do the opposite of sk_mem_charge() In addition, to achieve consolidation, updating sk_wmem_queued is removed from sk_mem_charge(). Next, to consolidate memory accounting functions, this patch adds memory accounting calls to network core functions. Moreover, present memory accounting call is renamed to new accounting call. Finally we replace present memory accounting calls with new interface in TCP and SCTP. Signed-off-by: Takahiro Yasui <tyasui@redhat.com> Signed-off-by: Hideo Aoki <haoki@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-31 08:11:19 +00:00
sk_mem_reclaim(sk);
if (tcp_check_oom(sk, 0)) {
tcp_set_state(sk, TCP_CLOSE);
tcp_send_active_reset(sk, GFP_ATOMIC);
__NET_INC_STATS(sock_net(sk),
LINUX_MIB_TCPABORTONMEMORY);
net: tcp: close sock if net namespace is exiting When a tcp socket is closed, if it detects that its net namespace is exiting, close immediately and do not wait for FIN sequence. For normal sockets, a reference is taken to their net namespace, so it will never exit while the socket is open. However, kernel sockets do not take a reference to their net namespace, so it may begin exiting while the kernel socket is still open. In this case if the kernel socket is a tcp socket, it will stay open trying to complete its close sequence. The sock's dst(s) hold a reference to their interface, which are all transferred to the namespace's loopback interface when the real interfaces are taken down. When the namespace tries to take down its loopback interface, it hangs waiting for all references to the loopback interface to release, which results in messages like: unregister_netdevice: waiting for lo to become free. Usage count = 1 These messages continue until the socket finally times out and closes. Since the net namespace cleanup holds the net_mutex while calling its registered pernet callbacks, any new net namespace initialization is blocked until the current net namespace finishes exiting. After this change, the tcp socket notices the exiting net namespace, and closes immediately, releasing its dst(s) and their reference to the loopback interface, which lets the net namespace continue exiting. Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1711407 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=97811 Signed-off-by: Dan Streetman <ddstreet@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-18 21:14:26 +00:00
} else if (!check_net(sock_net(sk))) {
/* Not possible to send reset; just close */
tcp_set_state(sk, TCP_CLOSE);
}
}
if (sk->sk_state == TCP_CLOSE) {
struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
/* We could get here with a non-NULL req if the socket is
* aborted (e.g., closed with unread data) before 3WHS
* finishes.
*/
if (req)
reqsk_fastopen_remove(sk, req, false);
inet_csk_destroy_sock(sk);
}
/* Otherwise, socket is reprieved until protocol close. */
out:
bh_unlock_sock(sk);
local_bh_enable();
release_sock(sk);
sock_put(sk);
}
EXPORT_SYMBOL(tcp_close);
/* These states need RST on ABORT according to RFC793 */
static inline bool tcp_need_reset(int state)
{
return (1 << state) &
(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_FIN_WAIT1 |
TCPF_FIN_WAIT2 | TCPF_SYN_RECV);
}
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 05:21:27 +00:00
static void tcp_rtx_queue_purge(struct sock *sk)
{
struct rb_node *p = rb_first(&sk->tcp_rtx_queue);
while (p) {
struct sk_buff *skb = rb_to_skb(p);
p = rb_next(p);
/* Since we are deleting whole queue, no need to
* list_del(&skb->tcp_tsorted_anchor)
*/
tcp_rtx_queue_unlink(skb, sk);
sk_wmem_free_skb(sk, skb);
}
}
void tcp_write_queue_purge(struct sock *sk)
{
struct sk_buff *skb;
tcp_chrono_stop(sk, TCP_CHRONO_BUSY);
while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
tcp_skb_tsorted_anchor_cleanup(skb);
sk_wmem_free_skb(sk, skb);
}
tcp: implement rb-tree based retransmit queue Using a linear list to store all skbs in write queue has been okay for quite a while : O(N) is not too bad when N < 500. Things get messy when N is the order of 100,000 : Modern TCP stacks want 10Gbit+ of throughput even with 200 ms RTT flows. 40 ns per cache line miss means a full scan can use 4 ms, blowing away CPU caches. SACK processing often can use various hints to avoid parsing whole retransmit queue. But with high packet losses and/or high reordering, hints no longer work. Sender has to process thousands of unfriendly SACK, accumulating a huge socket backlog, burning a cpu and massively dropping packets. Using an rb-tree for retransmit queue has been avoided for years because it added complexity and overhead, but now is the time to be more resistant and say no to quadratic behavior. 1) RTX queue is no longer part of the write queue : already sent skbs are stored in one rb-tree. 2) Since reaching the head of write queue no longer needs sk->sk_send_head, we added an union of sk_send_head and tcp_rtx_queue Tested: On receiver : netem on ingress : delay 150ms 200us loss 1 GRO disabled to force stress and SACK storms. for f in `seq 1 10` do ./netperf -H lpaa6 -l30 -- -K bbr -o THROUGHPUT|tail -1 done | awk '{print $0} {sum += $0} END {printf "%7u\n",sum}' Before patch : 323.87 351.48 339.59 338.62 306.72 204.07 304.93 291.88 202.47 176.88 2840 After patch: 1700.83 2207.98 2070.17 1544.26 2114.76 2124.89 1693.14 1080.91 2216.82 1299.94 18053 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-06 05:21:27 +00:00
tcp_rtx_queue_purge(sk);
INIT_LIST_HEAD(&tcp_sk(sk)->tsorted_sent_queue);
sk_mem_reclaim(sk);
tcp_clear_all_retrans_hints(tcp_sk(sk));
tcp_sk(sk)->packets_out = 0;
}
int tcp_disconnect(struct sock *sk, int flags)
{
struct inet_sock *inet = inet_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
int old_state = sk->sk_state;
if (old_state != TCP_CLOSE)
tcp_set_state(sk, TCP_CLOSE);
/* ABORT function of RFC793 */
if (old_state == TCP_LISTEN) {
inet_csk_listen_stop(sk);
} else if (unlikely(tp->repair)) {
sk->sk_err = ECONNABORTED;
} else if (tcp_need_reset(old_state) ||
(tp->snd_nxt != tp->write_seq &&
(1 << old_state) & (TCPF_CLOSING | TCPF_LAST_ACK))) {
/* The last check adjusts for discrepancy of Linux wrt. RFC
* states
*/
tcp_send_active_reset(sk, gfp_any());
sk->sk_err = ECONNRESET;
} else if (old_state == TCP_SYN_SENT)
sk->sk_err = ECONNRESET;
tcp_clear_xmit_timers(sk);
__skb_queue_purge(&sk->sk_receive_queue);
tp->copied_seq = tp->rcv_nxt;
tp->urg_data = 0;
tcp_write_queue_purge(sk);
net/tcp_fastopen: Disable active side TFO in certain scenarios Middlebox firewall issues can potentially cause server's data being blackholed after a successful 3WHS using TFO. Following are the related reports from Apple: https://www.nanog.org/sites/default/files/Paasch_Network_Support.pdf Slide 31 identifies an issue where the client ACK to the server's data sent during a TFO'd handshake is dropped. C ---> syn-data ---> S C <--- syn/ack ----- S C (accept & write) C <---- data ------- S C ----- ACK -> X S [retry and timeout] https://www.ietf.org/proceedings/94/slides/slides-94-tcpm-13.pdf Slide 5 shows a similar situation that the server's data gets dropped after 3WHS. C ---- syn-data ---> S C <--- syn/ack ----- S C ---- ack --------> S S (accept & write) C? X <- data ------ S [retry and timeout] This is the worst failure b/c the client can not detect such behavior to mitigate the situation (such as disabling TFO). Failing to proceed, the application (e.g., SSL library) may simply timeout and retry with TFO again, and the process repeats indefinitely. The proposed solution is to disable active TFO globally under the following circumstances: 1. client side TFO socket detects out of order FIN 2. client side TFO socket receives out of order RST We disable active side TFO globally for 1hr at first. Then if it happens again, we disable it for 2h, then 4h, 8h, ... And we reset the timeout to 1hr if a client side TFO sockets not opened on loopback has successfully received data segs from server. And we examine this condition during close(). The rational behind it is that when such firewall issue happens, application running on the client should eventually close the socket as it is not able to get the data it is expecting. Or application running on the server should close the socket as it is not able to receive any response from client. In both cases, out of order FIN or RST will get received on the client given that the firewall will not block them as no data are in those frames. And we want to disable active TFO globally as it helps if the middle box is very close to the client and most of the connections are likely to fail. Also, add a debug sysctl: tcp_fastopen_blackhole_detect_timeout_sec: the initial timeout to use when firewall blackhole issue happens. This can be set and read. When setting it to 0, it means to disable the active disable logic. Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-20 21:45:46 +00:00
tcp_fastopen_active_disable_ofo_check(sk);
2016-09-07 21:49:28 +00:00
skb_rbtree_purge(&tp->out_of_order_queue);
inet->inet_dport = 0;
if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
inet_reset_saddr(sk);
sk->sk_shutdown = 0;
sock_reset_flag(sk, SOCK_DONE);
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
tp->srtt_us = 0;
tp->rcv_rtt_last_tsecr = 0;
tp->write_seq += tp->max_window + 2;
if (tp->write_seq == 0)
tp->write_seq = 1;
icsk->icsk_backoff = 0;
tp->snd_cwnd = 2;
icsk->icsk_probes_out = 0;
tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
tp->snd_cwnd_cnt = 0;
tp->window_clamp = 0;
tp->delivered_ce = 0;
tcp_set_ca_state(sk, TCP_CA_Open);
tp->is_sack_reneg = 0;
tcp_clear_retrans(tp);
inet_csk_delack_init(sk);
/* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0
* issue in __tcp_select_window()
*/
icsk->icsk_ack.rcv_mss = TCP_MIN_MSS;
memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
__sk_dst_reset(sk);
dst_release(sk->sk_rx_dst);
sk->sk_rx_dst = NULL;
tcp_saved_syn_free(tp);
tp->compressed_ack = 0;
tp->bytes_sent = 0;
tp->bytes_retrans = 0;
tp->duplicate_sack[0].start_seq = 0;
tp->duplicate_sack[0].end_seq = 0;
tp->dsack_dups = 0;
tp->reord_seen = 0;
/* Clean up fastopen related fields */
tcp_free_fastopen_req(tp);
inet->defer_connect = 0;
WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
if (sk->sk_frag.page) {
put_page(sk->sk_frag.page);
sk->sk_frag.page = NULL;
sk->sk_frag.offset = 0;
}
sk->sk_error_report(sk);
return 0;
}
EXPORT_SYMBOL(tcp_disconnect);
static inline bool tcp_can_repair_sock(const struct sock *sk)
{
net: Allow userns root to control ipv4 Allow an unpriviled user who has created a user namespace, and then created a network namespace to effectively use the new network namespace, by reducing capable(CAP_NET_ADMIN) and capable(CAP_NET_RAW) calls to be ns_capable(net->user_ns, CAP_NET_ADMIN), or capable(net->user_ns, CAP_NET_RAW) calls. Settings that merely control a single network device are allowed. Either the network device is a logical network device where restrictions make no difference or the network device is hardware NIC that has been explicity moved from the initial network namespace. In general policy and network stack state changes are allowed while resource control is left unchanged. Allow creating raw sockets. Allow the SIOCSARP ioctl to control the arp cache. Allow the SIOCSIFFLAG ioctl to allow setting network device flags. Allow the SIOCSIFADDR ioctl to allow setting a netdevice ipv4 address. Allow the SIOCSIFBRDADDR ioctl to allow setting a netdevice ipv4 broadcast address. Allow the SIOCSIFDSTADDR ioctl to allow setting a netdevice ipv4 destination address. Allow the SIOCSIFNETMASK ioctl to allow setting a netdevice ipv4 netmask. Allow the SIOCADDRT and SIOCDELRT ioctls to allow adding and deleting ipv4 routes. Allow the SIOCADDTUNNEL, SIOCCHGTUNNEL and SIOCDELTUNNEL ioctls for adding, changing and deleting gre tunnels. Allow the SIOCADDTUNNEL, SIOCCHGTUNNEL and SIOCDELTUNNEL ioctls for adding, changing and deleting ipip tunnels. Allow the SIOCADDTUNNEL, SIOCCHGTUNNEL and SIOCDELTUNNEL ioctls for adding, changing and deleting ipsec virtual tunnel interfaces. Allow setting the MRT_INIT, MRT_DONE, MRT_ADD_VIF, MRT_DEL_VIF, MRT_ADD_MFC, MRT_DEL_MFC, MRT_ASSERT, MRT_PIM, MRT_TABLE socket options on multicast routing sockets. Allow setting and receiving IPOPT_CIPSO, IP_OPT_SEC, IP_OPT_SID and arbitrary ip options. Allow setting IP_SEC_POLICY/IP_XFRM_POLICY ipv4 socket option. Allow setting the IP_TRANSPARENT ipv4 socket option. Allow setting the TCP_REPAIR socket option. Allow setting the TCP_CONGESTION socket option. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-16 03:03:05 +00:00
return ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN) &&
(sk->sk_state != TCP_LISTEN);
}
static int tcp_repair_set_window(struct tcp_sock *tp, char __user *optbuf, int len)
{
struct tcp_repair_window opt;
if (!tp->repair)
return -EPERM;
if (len != sizeof(opt))
return -EINVAL;
if (copy_from_user(&opt, optbuf, sizeof(opt)))
return -EFAULT;
if (opt.max_window < opt.snd_wnd)
return -EINVAL;
if (after(opt.snd_wl1, tp->rcv_nxt + opt.rcv_wnd))
return -EINVAL;
if (after(opt.rcv_wup, tp->rcv_nxt))
return -EINVAL;
tp->snd_wl1 = opt.snd_wl1;
tp->snd_wnd = opt.snd_wnd;
tp->max_window = opt.max_window;
tp->rcv_wnd = opt.rcv_wnd;
tp->rcv_wup = opt.rcv_wup;
return 0;
}
static int tcp_repair_options_est(struct sock *sk,
struct tcp_repair_opt __user *optbuf, unsigned int len)
{
struct tcp_sock *tp = tcp_sk(sk);
struct tcp_repair_opt opt;
while (len >= sizeof(opt)) {
if (copy_from_user(&opt, optbuf, sizeof(opt)))
return -EFAULT;
optbuf++;
len -= sizeof(opt);
switch (opt.opt_code) {
case TCPOPT_MSS:
tp->rx_opt.mss_clamp = opt.opt_val;
tcp_mtup_init(sk);
break;
case TCPOPT_WINDOW:
{
u16 snd_wscale = opt.opt_val & 0xFFFF;
u16 rcv_wscale = opt.opt_val >> 16;
if (snd_wscale > TCP_MAX_WSCALE || rcv_wscale > TCP_MAX_WSCALE)
return -EFBIG;
tp->rx_opt.snd_wscale = snd_wscale;
tp->rx_opt.rcv_wscale = rcv_wscale;
tp->rx_opt.wscale_ok = 1;
}
break;
case TCPOPT_SACK_PERM:
if (opt.opt_val != 0)
return -EINVAL;
tp->rx_opt.sack_ok |= TCP_SACK_SEEN;
break;
case TCPOPT_TIMESTAMP:
if (opt.opt_val != 0)
return -EINVAL;
tp->rx_opt.tstamp_ok = 1;
break;
}
}
return 0;
}
/*
* Socket option code for TCP.
*/
static int do_tcp_setsockopt(struct sock *sk, int level,
int optname, char __user *optval, unsigned int optlen)
{
struct tcp_sock *tp = tcp_sk(sk);
struct inet_connection_sock *icsk = inet_csk(sk);
struct net *net = sock_net(sk);
int val;
int err = 0;
/* These are data/string values, all the others are ints */
switch (optname) {
case TCP_CONGESTION: {
char name[TCP_CA_NAME_MAX];
if (optlen < 1)
return -EINVAL;
val = strncpy_from_user(name, optval,
min_t(long, TCP_CA_NAME_MAX-1, optlen));
if (val < 0)
return -EFAULT;
name[val] = 0;
lock_sock(sk);
err = tcp_set_congestion_control(sk, name, true, true);
release_sock(sk);
return err;
}
case TCP_ULP: {
char name[TCP_ULP_NAME_MAX];
if (optlen < 1)
return -EINVAL;
val = strncpy_from_user(name, optval,
min_t(long, TCP_ULP_NAME_MAX - 1,
optlen));
if (val < 0)
return -EFAULT;
name[val] = 0;
lock_sock(sk);
err = tcp_set_ulp(sk, name);
release_sock(sk);
return err;
}
case TCP_FASTOPEN_KEY: {
__u8 key[TCP_FASTOPEN_KEY_LENGTH];
if (optlen != sizeof(key))
return -EINVAL;
if (copy_from_user(key, optval, optlen))
return -EFAULT;
return tcp_fastopen_reset_cipher(net, sk, key, sizeof(key));
}
default:
/* fallthru */
break;
}
if (optlen < sizeof(int))
return -EINVAL;
if (get_user(val, (int __user *)optval))
return -EFAULT;
lock_sock(sk);
switch (optname) {
case TCP_MAXSEG:
/* Values greater than interface MTU won't take effect. However
* at the point when this call is done we typically don't yet
* know which interface is going to be used
*/
if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) {
err = -EINVAL;
break;
}
tp->rx_opt.user_mss = val;
break;
case TCP_NODELAY:
if (val) {
/* TCP_NODELAY is weaker than TCP_CORK, so that
* this option on corked socket is remembered, but
* it is not activated until cork is cleared.
*
* However, when TCP_NODELAY is set we make
* an explicit push, which overrides even TCP_CORK
* for currently queued segments.
*/
tp->nonagle |= TCP_NAGLE_OFF|TCP_NAGLE_PUSH;
[TCP]: Sed magic converts func(sk, tp, ...) -> func(sk, ...) This is (mostly) automated change using magic: sed -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e 's|struct sock \*sk,[\n\t ]*struct tcp_sock \*tp\([^{]*\n{\n\)| struct sock \*sk\1\tstruct tcp_sock *tp = tcp_sk(sk);\n|g' -e 's|struct sock \*sk, struct tcp_sock \*tp| struct sock \*sk|g' -e 's|sk, tp\([^-]\)|sk\1|g' Fixed four unused variable (tp) warnings that were introduced. In addition, manually added newlines after local variables and tweaked function arguments positioning. $ gcc --version gcc (GCC) 4.1.1 20060525 (Red Hat 4.1.1-1) ... $ codiff -fV built-in.o.old built-in.o.new net/ipv4/route.c: rt_cache_flush | +14 1 function changed, 14 bytes added net/ipv4/tcp.c: tcp_setsockopt | -5 tcp_sendpage | -25 tcp_sendmsg | -16 3 functions changed, 46 bytes removed net/ipv4/tcp_input.c: tcp_try_undo_recovery | +3 tcp_try_undo_dsack | +2 tcp_mark_head_lost | -12 tcp_ack | -15 tcp_event_data_recv | -32 tcp_rcv_state_process | -10 tcp_rcv_established | +1 7 functions changed, 6 bytes added, 69 bytes removed, diff: -63 net/ipv4/tcp_output.c: update_send_head | -9 tcp_transmit_skb | +19 tcp_cwnd_validate | +1 tcp_write_wakeup | -17 __tcp_push_pending_frames | -25 tcp_push_one | -8 tcp_send_fin | -4 7 functions changed, 20 bytes added, 63 bytes removed, diff: -43 built-in.o.new: 18 functions changed, 40 bytes added, 178 bytes removed, diff: -138 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-21 05:18:02 +00:00
tcp_push_pending_frames(sk);
} else {
tp->nonagle &= ~TCP_NAGLE_OFF;
}
break;
case TCP_THIN_LINEAR_TIMEOUTS:
if (val < 0 || val > 1)
err = -EINVAL;
else
tp->thin_lto = val;
break;
case TCP_THIN_DUPACK:
if (val < 0 || val > 1)
err = -EINVAL;
break;
case TCP_REPAIR:
if (!tcp_can_repair_sock(sk))
err = -EPERM;
else if (val == TCP_REPAIR_ON) {
tp->repair = 1;
sk->sk_reuse = SK_FORCE_REUSE;
tp->repair_queue = TCP_NO_QUEUE;
} else if (val == TCP_REPAIR_OFF) {
tp->repair = 0;
sk->sk_reuse = SK_NO_REUSE;
tcp_send_window_probe(sk);
} else if (val == TCP_REPAIR_OFF_NO_WP) {
tp->repair = 0;
sk->sk_reuse = SK_NO_REUSE;
} else
err = -EINVAL;
break;
case TCP_REPAIR_QUEUE:
if (!tp->repair)
err = -EPERM;
else if ((unsigned int)val < TCP_QUEUES_NR)
tp->repair_queue = val;
else
err = -EINVAL;
break;
case TCP_QUEUE_SEQ:
if (sk->sk_state != TCP_CLOSE)
err = -EPERM;
else if (tp->repair_queue == TCP_SEND_QUEUE)
tp->write_seq = val;
else if (tp->repair_queue == TCP_RECV_QUEUE)
tp->rcv_nxt = val;
else
err = -EINVAL;
break;
case TCP_REPAIR_OPTIONS:
if (!tp->repair)
err = -EINVAL;
else if (sk->sk_state == TCP_ESTABLISHED)
err = tcp_repair_options_est(sk,
(struct tcp_repair_opt __user *)optval,
optlen);
else
err = -EPERM;
break;
case TCP_CORK:
/* When set indicates to always queue non-full frames.
* Later the user clears this option and we transmit
* any pending partial frames in the queue. This is
* meant to be used alongside sendfile() to get properly
* filled frames when the user (for example) must write
* out headers with a write() call first and then use
* sendfile to send out the data parts.
*
* TCP_CORK can be set together with TCP_NODELAY and it is
* stronger than TCP_NODELAY.
*/
if (val) {
tp->nonagle |= TCP_NAGLE_CORK;
} else {
tp->nonagle &= ~TCP_NAGLE_CORK;
if (tp->nonagle&TCP_NAGLE_OFF)
tp->nonagle |= TCP_NAGLE_PUSH;
[TCP]: Sed magic converts func(sk, tp, ...) -> func(sk, ...) This is (mostly) automated change using magic: sed -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e '/struct sock \*sk/ N' -e 's|struct sock \*sk,[\n\t ]*struct tcp_sock \*tp\([^{]*\n{\n\)| struct sock \*sk\1\tstruct tcp_sock *tp = tcp_sk(sk);\n|g' -e 's|struct sock \*sk, struct tcp_sock \*tp| struct sock \*sk|g' -e 's|sk, tp\([^-]\)|sk\1|g' Fixed four unused variable (tp) warnings that were introduced. In addition, manually added newlines after local variables and tweaked function arguments positioning. $ gcc --version gcc (GCC) 4.1.1 20060525 (Red Hat 4.1.1-1) ... $ codiff -fV built-in.o.old built-in.o.new net/ipv4/route.c: rt_cache_flush | +14 1 function changed, 14 bytes added net/ipv4/tcp.c: tcp_setsockopt | -5 tcp_sendpage | -25 tcp_sendmsg | -16 3 functions changed, 46 bytes removed net/ipv4/tcp_input.c: tcp_try_undo_recovery | +3 tcp_try_undo_dsack | +2 tcp_mark_head_lost | -12 tcp_ack | -15 tcp_event_data_recv | -32 tcp_rcv_state_process | -10 tcp_rcv_established | +1 7 functions changed, 6 bytes added, 69 bytes removed, diff: -63 net/ipv4/tcp_output.c: update_send_head | -9 tcp_transmit_skb | +19 tcp_cwnd_validate | +1 tcp_write_wakeup | -17 __tcp_push_pending_frames | -25 tcp_push_one | -8 tcp_send_fin | -4 7 functions changed, 20 bytes added, 63 bytes removed, diff: -43 built-in.o.new: 18 functions changed, 40 bytes added, 178 bytes removed, diff: -138 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-21 05:18:02 +00:00
tcp_push_pending_frames(sk);
}
break;
case TCP_KEEPIDLE:
if (val < 1 || val > MAX_TCP_KEEPIDLE)
err = -EINVAL;
else {
tp->keepalive_time = val * HZ;
if (sock_flag(sk, SOCK_KEEPOPEN) &&
!((1 << sk->sk_state) &
(TCPF_CLOSE | TCPF_LISTEN))) {
u32 elapsed = keepalive_time_elapsed(tp);
if (tp->keepalive_time > elapsed)
elapsed = tp->keepalive_time - elapsed;
else
elapsed = 0;
inet_csk_reset_keepalive_timer(sk, elapsed);
}
}
break;
case TCP_KEEPINTVL:
if (val < 1 || val > MAX_TCP_KEEPINTVL)
err = -EINVAL;
else
tp->keepalive_intvl = val * HZ;
break;
case TCP_KEEPCNT:
if (val < 1 || val > MAX_TCP_KEEPCNT)
err = -EINVAL;
else
tp->keepalive_probes = val;
break;
case TCP_SYNCNT:
if (val < 1 || val > MAX_TCP_SYNCNT)
err = -EINVAL;
else
icsk->icsk_syn_retries = val;
break;
case TCP_SAVE_SYN:
if (val < 0 || val > 1)
err = -EINVAL;
else
tp->save_syn = val;
break;
case TCP_LINGER2:
if (val < 0)
tp->linger2 = -1;
else if (val > net->ipv4.sysctl_tcp_fin_timeout / HZ)
tp->linger2 = 0;
else
tp->linger2 = val * HZ;
break;
case TCP_DEFER_ACCEPT:
/* Translate value in seconds to number of retransmits */
icsk->icsk_accept_queue.rskq_defer_accept =
secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,
TCP_RTO_MAX / HZ);
break;
case TCP_WINDOW_CLAMP:
if (!val) {
if (sk->sk_state != TCP_CLOSE) {
err = -EINVAL;
break;
}
tp->window_clamp = 0;
} else
tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
SOCK_MIN_RCVBUF / 2 : val;
break;
case TCP_QUICKACK:
if (!val) {
icsk->icsk_ack.pingpong = 1;
} else {
icsk->icsk_ack.pingpong = 0;
if ((1 << sk->sk_state) &
(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
inet_csk_ack_scheduled(sk)) {
icsk->icsk_ack.pending |= ICSK_ACK_PUSHED;
tcp_cleanup_rbuf(sk, 1);
if (!(val & 1))
icsk->icsk_ack.pingpong = 1;
}
}
break;
#ifdef CONFIG_TCP_MD5SIG
case TCP_MD5SIG:
case TCP_MD5SIG_EXT:
tcp: md5: reject TCP_MD5SIG or TCP_MD5SIG_EXT on established sockets syzbot/KMSAN reported an uninit-value in tcp_parse_options() [1] I believe this was caused by a TCP_MD5SIG being set on live flow. This is highly unexpected, since TCP option space is limited. For instance, presence of TCP MD5 option automatically disables TCP TimeStamp option at SYN/SYNACK time, which we can not do once flow has been established. Really, adding/deleting an MD5 key only makes sense on sockets in CLOSE or LISTEN state. [1] BUG: KMSAN: uninit-value in tcp_parse_options+0xd74/0x1a30 net/ipv4/tcp_input.c:3720 CPU: 1 PID: 6177 Comm: syzkaller192004 Not tainted 4.16.0+ #83 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 tcp_parse_options+0xd74/0x1a30 net/ipv4/tcp_input.c:3720 tcp_fast_parse_options net/ipv4/tcp_input.c:3858 [inline] tcp_validate_incoming+0x4f1/0x2790 net/ipv4/tcp_input.c:5184 tcp_rcv_established+0xf60/0x2bb0 net/ipv4/tcp_input.c:5453 tcp_v4_do_rcv+0x6cd/0xd90 net/ipv4/tcp_ipv4.c:1469 sk_backlog_rcv include/net/sock.h:908 [inline] __release_sock+0x2d6/0x680 net/core/sock.c:2271 release_sock+0x97/0x2a0 net/core/sock.c:2786 tcp_sendmsg+0xd6/0x100 net/ipv4/tcp.c:1464 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] SYSC_sendto+0x6c3/0x7e0 net/socket.c:1747 SyS_sendto+0x8a/0xb0 net/socket.c:1715 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x448fe9 RSP: 002b:00007fd472c64d38 EFLAGS: 00000216 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00000000006e5a30 RCX: 0000000000448fe9 RDX: 000000000000029f RSI: 0000000020a88f88 RDI: 0000000000000004 RBP: 00000000006e5a34 R08: 0000000020e68000 R09: 0000000000000010 R10: 00000000200007fd R11: 0000000000000216 R12: 0000000000000000 R13: 00007fff074899ef R14: 00007fd472c659c0 R15: 0000000000000009 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321 slab_post_alloc_hook mm/slab.h:445 [inline] slab_alloc_node mm/slub.c:2737 [inline] __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369 __kmalloc_reserve net/core/skbuff.c:138 [inline] __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206 alloc_skb include/linux/skbuff.h:984 [inline] tcp_send_ack+0x18c/0x910 net/ipv4/tcp_output.c:3624 __tcp_ack_snd_check net/ipv4/tcp_input.c:5040 [inline] tcp_ack_snd_check net/ipv4/tcp_input.c:5053 [inline] tcp_rcv_established+0x2103/0x2bb0 net/ipv4/tcp_input.c:5469 tcp_v4_do_rcv+0x6cd/0xd90 net/ipv4/tcp_ipv4.c:1469 sk_backlog_rcv include/net/sock.h:908 [inline] __release_sock+0x2d6/0x680 net/core/sock.c:2271 release_sock+0x97/0x2a0 net/core/sock.c:2786 tcp_sendmsg+0xd6/0x100 net/ipv4/tcp.c:1464 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] SYSC_sendto+0x6c3/0x7e0 net/socket.c:1747 SyS_sendto+0x8a/0xb0 net/socket.c:1715 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Fixes: cfb6eeb4c860 ("[TCP]: MD5 Signature Option (RFC2385) support.") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-11 21:36:28 +00:00
if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))
err = tp->af_specific->md5_parse(sk, optname, optval, optlen);
else
err = -EINVAL;
break;
#endif
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-27 19:13:28 +00:00
case TCP_USER_TIMEOUT:
tcp: abort orphan sockets stalling on zero window probes Currently we have two different policies for orphan sockets that repeatedly stall on zero window ACKs. If a socket gets a zero window ACK when it is transmitting data, the RTO is used to probe the window. The socket is aborted after roughly tcp_orphan_retries() retries (as in tcp_write_timeout()). But if the socket was idle when it received the zero window ACK, and later wants to send more data, we use the probe timer to probe the window. If the receiver always returns zero window ACKs, icsk_probes keeps getting reset in tcp_ack() and the orphan socket can stall forever until the system reaches the orphan limit (as commented in tcp_probe_timer()). This opens up a simple attack to create lots of hanging orphan sockets to burn the memory and the CPU, as demonstrated in the recent netdev post "TCP connection will hang in FIN_WAIT1 after closing if zero window is advertised." http://www.spinics.net/lists/netdev/msg296539.html This patch follows the design in RTO-based probe: we abort an orphan socket stalling on zero window when the probe timer reaches both the maximum backoff and the maximum RTO. For example, an 100ms RTT connection will timeout after roughly 153 seconds (0.3 + 0.6 + .... + 76.8) if the receiver keeps the window shut. If the orphan socket passes this check, but the system already has too many orphans (as in tcp_out_of_resources()), we still abort it but we'll also send an RST packet as the connection may still be active. In addition, we change TCP_USER_TIMEOUT to cover (life or dead) sockets stalled on zero-window probes. This changes the semantics of TCP_USER_TIMEOUT slightly because it previously only applies when the socket has pending transmission. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Reported-by: Andrey Dmitrov <andrey.dmitrov@oktetlabs.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-29 20:20:38 +00:00
/* Cap the max time in ms TCP will retry or probe the window
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-27 19:13:28 +00:00
* before giving up and aborting (ETIMEDOUT) a connection.
*/
if (val < 0)
err = -EINVAL;
else
icsk->icsk_user_timeout = val;
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-27 19:13:28 +00:00
break;
case TCP_FASTOPEN:
if (val >= 0 && ((1 << sk->sk_state) & (TCPF_CLOSE |
tcp: Do not call tcp_fastopen_reset_cipher from interrupt context tcp_fastopen_reset_cipher really cannot be called from interrupt context. It allocates the tcp_fastopen_context with GFP_KERNEL and calls crypto_alloc_cipher, which allocates all kind of stuff with GFP_KERNEL. Thus, we might sleep when the key-generation is triggered by an incoming TFO cookie-request which would then happen in interrupt- context, as shown by enabling CONFIG_DEBUG_ATOMIC_SLEEP: [ 36.001813] BUG: sleeping function called from invalid context at mm/slub.c:1266 [ 36.003624] in_atomic(): 1, irqs_disabled(): 0, pid: 1016, name: packetdrill [ 36.004859] CPU: 1 PID: 1016 Comm: packetdrill Not tainted 4.1.0-rc7 #14 [ 36.006085] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [ 36.008250] 00000000000004f2 ffff88007f8838a8 ffffffff8171d53a ffff880075a084a8 [ 36.009630] ffff880075a08000 ffff88007f8838c8 ffffffff810967d3 ffff88007f883928 [ 36.011076] 0000000000000000 ffff88007f8838f8 ffffffff81096892 ffff88007f89be00 [ 36.012494] Call Trace: [ 36.012953] <IRQ> [<ffffffff8171d53a>] dump_stack+0x4f/0x6d [ 36.014085] [<ffffffff810967d3>] ___might_sleep+0x103/0x170 [ 36.015117] [<ffffffff81096892>] __might_sleep+0x52/0x90 [ 36.016117] [<ffffffff8118e887>] kmem_cache_alloc_trace+0x47/0x190 [ 36.017266] [<ffffffff81680d82>] ? tcp_fastopen_reset_cipher+0x42/0x130 [ 36.018485] [<ffffffff81680d82>] tcp_fastopen_reset_cipher+0x42/0x130 [ 36.019679] [<ffffffff81680f01>] tcp_fastopen_init_key_once+0x61/0x70 [ 36.020884] [<ffffffff81680f2c>] __tcp_fastopen_cookie_gen+0x1c/0x60 [ 36.022058] [<ffffffff816814ff>] tcp_try_fastopen+0x58f/0x730 [ 36.023118] [<ffffffff81671788>] tcp_conn_request+0x3e8/0x7b0 [ 36.024185] [<ffffffff810e3872>] ? __module_text_address+0x12/0x60 [ 36.025327] [<ffffffff8167b2e1>] tcp_v4_conn_request+0x51/0x60 [ 36.026410] [<ffffffff816727e0>] tcp_rcv_state_process+0x190/0xda0 [ 36.027556] [<ffffffff81661f97>] ? __inet_lookup_established+0x47/0x170 [ 36.028784] [<ffffffff8167c2ad>] tcp_v4_do_rcv+0x16d/0x3d0 [ 36.029832] [<ffffffff812e6806>] ? security_sock_rcv_skb+0x16/0x20 [ 36.030936] [<ffffffff8167cc8a>] tcp_v4_rcv+0x77a/0x7b0 [ 36.031875] [<ffffffff816af8c3>] ? iptable_filter_hook+0x33/0x70 [ 36.032953] [<ffffffff81657d22>] ip_local_deliver_finish+0x92/0x1f0 [ 36.034065] [<ffffffff81657f1a>] ip_local_deliver+0x9a/0xb0 [ 36.035069] [<ffffffff81657c90>] ? ip_rcv+0x3d0/0x3d0 [ 36.035963] [<ffffffff81657569>] ip_rcv_finish+0x119/0x330 [ 36.036950] [<ffffffff81657ba7>] ip_rcv+0x2e7/0x3d0 [ 36.037847] [<ffffffff81610652>] __netif_receive_skb_core+0x552/0x930 [ 36.038994] [<ffffffff81610a57>] __netif_receive_skb+0x27/0x70 [ 36.040033] [<ffffffff81610b72>] process_backlog+0xd2/0x1f0 [ 36.041025] [<ffffffff81611482>] net_rx_action+0x122/0x310 [ 36.042007] [<ffffffff81076743>] __do_softirq+0x103/0x2f0 [ 36.042978] [<ffffffff81723e3c>] do_softirq_own_stack+0x1c/0x30 This patch moves the call to tcp_fastopen_init_key_once to the places where a listener socket creates its TFO-state, which always happens in user-context (either from the setsockopt, or implicitly during the listen()-call) Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Fixes: 222e83d2e0ae ("tcp: switch tcp_fastopen key generation to net_get_random_once") Signed-off-by: Christoph Paasch <cpaasch@apple.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-18 16:15:34 +00:00
TCPF_LISTEN))) {
tcp_fastopen_init_key_once(net);
tcp: Do not call tcp_fastopen_reset_cipher from interrupt context tcp_fastopen_reset_cipher really cannot be called from interrupt context. It allocates the tcp_fastopen_context with GFP_KERNEL and calls crypto_alloc_cipher, which allocates all kind of stuff with GFP_KERNEL. Thus, we might sleep when the key-generation is triggered by an incoming TFO cookie-request which would then happen in interrupt- context, as shown by enabling CONFIG_DEBUG_ATOMIC_SLEEP: [ 36.001813] BUG: sleeping function called from invalid context at mm/slub.c:1266 [ 36.003624] in_atomic(): 1, irqs_disabled(): 0, pid: 1016, name: packetdrill [ 36.004859] CPU: 1 PID: 1016 Comm: packetdrill Not tainted 4.1.0-rc7 #14 [ 36.006085] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [ 36.008250] 00000000000004f2 ffff88007f8838a8 ffffffff8171d53a ffff880075a084a8 [ 36.009630] ffff880075a08000 ffff88007f8838c8 ffffffff810967d3 ffff88007f883928 [ 36.011076] 0000000000000000 ffff88007f8838f8 ffffffff81096892 ffff88007f89be00 [ 36.012494] Call Trace: [ 36.012953] <IRQ> [<ffffffff8171d53a>] dump_stack+0x4f/0x6d [ 36.014085] [<ffffffff810967d3>] ___might_sleep+0x103/0x170 [ 36.015117] [<ffffffff81096892>] __might_sleep+0x52/0x90 [ 36.016117] [<ffffffff8118e887>] kmem_cache_alloc_trace+0x47/0x190 [ 36.017266] [<ffffffff81680d82>] ? tcp_fastopen_reset_cipher+0x42/0x130 [ 36.018485] [<ffffffff81680d82>] tcp_fastopen_reset_cipher+0x42/0x130 [ 36.019679] [<ffffffff81680f01>] tcp_fastopen_init_key_once+0x61/0x70 [ 36.020884] [<ffffffff81680f2c>] __tcp_fastopen_cookie_gen+0x1c/0x60 [ 36.022058] [<ffffffff816814ff>] tcp_try_fastopen+0x58f/0x730 [ 36.023118] [<ffffffff81671788>] tcp_conn_request+0x3e8/0x7b0 [ 36.024185] [<ffffffff810e3872>] ? __module_text_address+0x12/0x60 [ 36.025327] [<ffffffff8167b2e1>] tcp_v4_conn_request+0x51/0x60 [ 36.026410] [<ffffffff816727e0>] tcp_rcv_state_process+0x190/0xda0 [ 36.027556] [<ffffffff81661f97>] ? __inet_lookup_established+0x47/0x170 [ 36.028784] [<ffffffff8167c2ad>] tcp_v4_do_rcv+0x16d/0x3d0 [ 36.029832] [<ffffffff812e6806>] ? security_sock_rcv_skb+0x16/0x20 [ 36.030936] [<ffffffff8167cc8a>] tcp_v4_rcv+0x77a/0x7b0 [ 36.031875] [<ffffffff816af8c3>] ? iptable_filter_hook+0x33/0x70 [ 36.032953] [<ffffffff81657d22>] ip_local_deliver_finish+0x92/0x1f0 [ 36.034065] [<ffffffff81657f1a>] ip_local_deliver+0x9a/0xb0 [ 36.035069] [<ffffffff81657c90>] ? ip_rcv+0x3d0/0x3d0 [ 36.035963] [<ffffffff81657569>] ip_rcv_finish+0x119/0x330 [ 36.036950] [<ffffffff81657ba7>] ip_rcv+0x2e7/0x3d0 [ 36.037847] [<ffffffff81610652>] __netif_receive_skb_core+0x552/0x930 [ 36.038994] [<ffffffff81610a57>] __netif_receive_skb+0x27/0x70 [ 36.040033] [<ffffffff81610b72>] process_backlog+0xd2/0x1f0 [ 36.041025] [<ffffffff81611482>] net_rx_action+0x122/0x310 [ 36.042007] [<ffffffff81076743>] __do_softirq+0x103/0x2f0 [ 36.042978] [<ffffffff81723e3c>] do_softirq_own_stack+0x1c/0x30 This patch moves the call to tcp_fastopen_init_key_once to the places where a listener socket creates its TFO-state, which always happens in user-context (either from the setsockopt, or implicitly during the listen()-call) Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Fixes: 222e83d2e0ae ("tcp: switch tcp_fastopen key generation to net_get_random_once") Signed-off-by: Christoph Paasch <cpaasch@apple.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-18 16:15:34 +00:00
fastopen_queue_tune(sk, val);
tcp: Do not call tcp_fastopen_reset_cipher from interrupt context tcp_fastopen_reset_cipher really cannot be called from interrupt context. It allocates the tcp_fastopen_context with GFP_KERNEL and calls crypto_alloc_cipher, which allocates all kind of stuff with GFP_KERNEL. Thus, we might sleep when the key-generation is triggered by an incoming TFO cookie-request which would then happen in interrupt- context, as shown by enabling CONFIG_DEBUG_ATOMIC_SLEEP: [ 36.001813] BUG: sleeping function called from invalid context at mm/slub.c:1266 [ 36.003624] in_atomic(): 1, irqs_disabled(): 0, pid: 1016, name: packetdrill [ 36.004859] CPU: 1 PID: 1016 Comm: packetdrill Not tainted 4.1.0-rc7 #14 [ 36.006085] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [ 36.008250] 00000000000004f2 ffff88007f8838a8 ffffffff8171d53a ffff880075a084a8 [ 36.009630] ffff880075a08000 ffff88007f8838c8 ffffffff810967d3 ffff88007f883928 [ 36.011076] 0000000000000000 ffff88007f8838f8 ffffffff81096892 ffff88007f89be00 [ 36.012494] Call Trace: [ 36.012953] <IRQ> [<ffffffff8171d53a>] dump_stack+0x4f/0x6d [ 36.014085] [<ffffffff810967d3>] ___might_sleep+0x103/0x170 [ 36.015117] [<ffffffff81096892>] __might_sleep+0x52/0x90 [ 36.016117] [<ffffffff8118e887>] kmem_cache_alloc_trace+0x47/0x190 [ 36.017266] [<ffffffff81680d82>] ? tcp_fastopen_reset_cipher+0x42/0x130 [ 36.018485] [<ffffffff81680d82>] tcp_fastopen_reset_cipher+0x42/0x130 [ 36.019679] [<ffffffff81680f01>] tcp_fastopen_init_key_once+0x61/0x70 [ 36.020884] [<ffffffff81680f2c>] __tcp_fastopen_cookie_gen+0x1c/0x60 [ 36.022058] [<ffffffff816814ff>] tcp_try_fastopen+0x58f/0x730 [ 36.023118] [<ffffffff81671788>] tcp_conn_request+0x3e8/0x7b0 [ 36.024185] [<ffffffff810e3872>] ? __module_text_address+0x12/0x60 [ 36.025327] [<ffffffff8167b2e1>] tcp_v4_conn_request+0x51/0x60 [ 36.026410] [<ffffffff816727e0>] tcp_rcv_state_process+0x190/0xda0 [ 36.027556] [<ffffffff81661f97>] ? __inet_lookup_established+0x47/0x170 [ 36.028784] [<ffffffff8167c2ad>] tcp_v4_do_rcv+0x16d/0x3d0 [ 36.029832] [<ffffffff812e6806>] ? security_sock_rcv_skb+0x16/0x20 [ 36.030936] [<ffffffff8167cc8a>] tcp_v4_rcv+0x77a/0x7b0 [ 36.031875] [<ffffffff816af8c3>] ? iptable_filter_hook+0x33/0x70 [ 36.032953] [<ffffffff81657d22>] ip_local_deliver_finish+0x92/0x1f0 [ 36.034065] [<ffffffff81657f1a>] ip_local_deliver+0x9a/0xb0 [ 36.035069] [<ffffffff81657c90>] ? ip_rcv+0x3d0/0x3d0 [ 36.035963] [<ffffffff81657569>] ip_rcv_finish+0x119/0x330 [ 36.036950] [<ffffffff81657ba7>] ip_rcv+0x2e7/0x3d0 [ 36.037847] [<ffffffff81610652>] __netif_receive_skb_core+0x552/0x930 [ 36.038994] [<ffffffff81610a57>] __netif_receive_skb+0x27/0x70 [ 36.040033] [<ffffffff81610b72>] process_backlog+0xd2/0x1f0 [ 36.041025] [<ffffffff81611482>] net_rx_action+0x122/0x310 [ 36.042007] [<ffffffff81076743>] __do_softirq+0x103/0x2f0 [ 36.042978] [<ffffffff81723e3c>] do_softirq_own_stack+0x1c/0x30 This patch moves the call to tcp_fastopen_init_key_once to the places where a listener socket creates its TFO-state, which always happens in user-context (either from the setsockopt, or implicitly during the listen()-call) Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Fixes: 222e83d2e0ae ("tcp: switch tcp_fastopen key generation to net_get_random_once") Signed-off-by: Christoph Paasch <cpaasch@apple.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-18 16:15:34 +00:00
} else {
err = -EINVAL;
tcp: Do not call tcp_fastopen_reset_cipher from interrupt context tcp_fastopen_reset_cipher really cannot be called from interrupt context. It allocates the tcp_fastopen_context with GFP_KERNEL and calls crypto_alloc_cipher, which allocates all kind of stuff with GFP_KERNEL. Thus, we might sleep when the key-generation is triggered by an incoming TFO cookie-request which would then happen in interrupt- context, as shown by enabling CONFIG_DEBUG_ATOMIC_SLEEP: [ 36.001813] BUG: sleeping function called from invalid context at mm/slub.c:1266 [ 36.003624] in_atomic(): 1, irqs_disabled(): 0, pid: 1016, name: packetdrill [ 36.004859] CPU: 1 PID: 1016 Comm: packetdrill Not tainted 4.1.0-rc7 #14 [ 36.006085] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [ 36.008250] 00000000000004f2 ffff88007f8838a8 ffffffff8171d53a ffff880075a084a8 [ 36.009630] ffff880075a08000 ffff88007f8838c8 ffffffff810967d3 ffff88007f883928 [ 36.011076] 0000000000000000 ffff88007f8838f8 ffffffff81096892 ffff88007f89be00 [ 36.012494] Call Trace: [ 36.012953] <IRQ> [<ffffffff8171d53a>] dump_stack+0x4f/0x6d [ 36.014085] [<ffffffff810967d3>] ___might_sleep+0x103/0x170 [ 36.015117] [<ffffffff81096892>] __might_sleep+0x52/0x90 [ 36.016117] [<ffffffff8118e887>] kmem_cache_alloc_trace+0x47/0x190 [ 36.017266] [<ffffffff81680d82>] ? tcp_fastopen_reset_cipher+0x42/0x130 [ 36.018485] [<ffffffff81680d82>] tcp_fastopen_reset_cipher+0x42/0x130 [ 36.019679] [<ffffffff81680f01>] tcp_fastopen_init_key_once+0x61/0x70 [ 36.020884] [<ffffffff81680f2c>] __tcp_fastopen_cookie_gen+0x1c/0x60 [ 36.022058] [<ffffffff816814ff>] tcp_try_fastopen+0x58f/0x730 [ 36.023118] [<ffffffff81671788>] tcp_conn_request+0x3e8/0x7b0 [ 36.024185] [<ffffffff810e3872>] ? __module_text_address+0x12/0x60 [ 36.025327] [<ffffffff8167b2e1>] tcp_v4_conn_request+0x51/0x60 [ 36.026410] [<ffffffff816727e0>] tcp_rcv_state_process+0x190/0xda0 [ 36.027556] [<ffffffff81661f97>] ? __inet_lookup_established+0x47/0x170 [ 36.028784] [<ffffffff8167c2ad>] tcp_v4_do_rcv+0x16d/0x3d0 [ 36.029832] [<ffffffff812e6806>] ? security_sock_rcv_skb+0x16/0x20 [ 36.030936] [<ffffffff8167cc8a>] tcp_v4_rcv+0x77a/0x7b0 [ 36.031875] [<ffffffff816af8c3>] ? iptable_filter_hook+0x33/0x70 [ 36.032953] [<ffffffff81657d22>] ip_local_deliver_finish+0x92/0x1f0 [ 36.034065] [<ffffffff81657f1a>] ip_local_deliver+0x9a/0xb0 [ 36.035069] [<ffffffff81657c90>] ? ip_rcv+0x3d0/0x3d0 [ 36.035963] [<ffffffff81657569>] ip_rcv_finish+0x119/0x330 [ 36.036950] [<ffffffff81657ba7>] ip_rcv+0x2e7/0x3d0 [ 36.037847] [<ffffffff81610652>] __netif_receive_skb_core+0x552/0x930 [ 36.038994] [<ffffffff81610a57>] __netif_receive_skb+0x27/0x70 [ 36.040033] [<ffffffff81610b72>] process_backlog+0xd2/0x1f0 [ 36.041025] [<ffffffff81611482>] net_rx_action+0x122/0x310 [ 36.042007] [<ffffffff81076743>] __do_softirq+0x103/0x2f0 [ 36.042978] [<ffffffff81723e3c>] do_softirq_own_stack+0x1c/0x30 This patch moves the call to tcp_fastopen_init_key_once to the places where a listener socket creates its TFO-state, which always happens in user-context (either from the setsockopt, or implicitly during the listen()-call) Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Fixes: 222e83d2e0ae ("tcp: switch tcp_fastopen key generation to net_get_random_once") Signed-off-by: Christoph Paasch <cpaasch@apple.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-18 16:15:34 +00:00
}
break;
net/tcp-fastopen: Add new API support This patch adds a new socket option, TCP_FASTOPEN_CONNECT, as an alternative way to perform Fast Open on the active side (client). Prior to this patch, a client needs to replace the connect() call with sendto(MSG_FASTOPEN). This can be cumbersome for applications who want to use Fast Open: these socket operations are often done in lower layer libraries used by many other applications. Changing these libraries and/or the socket call sequences are not trivial. A more convenient approach is to perform Fast Open by simply enabling a socket option when the socket is created w/o changing other socket calls sequence: s = socket() create a new socket setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT …); newly introduced sockopt If set, new functionality described below will be used. Return ENOTSUPP if TFO is not supported or not enabled in the kernel. connect() With cookie present, return 0 immediately. With no cookie, initiate 3WHS with TFO cookie-request option and return -1 with errno = EINPROGRESS. write()/sendmsg() With cookie present, send out SYN with data and return the number of bytes buffered. With no cookie, and 3WHS not yet completed, return -1 with errno = EINPROGRESS. No MSG_FASTOPEN flag is needed. read() Return -1 with errno = EWOULDBLOCK/EAGAIN if connect() is called but write() is not called yet. Return -1 with errno = EWOULDBLOCK/EAGAIN if connection is established but no msg is received yet. Return number of bytes read if socket is established and there is msg received. The new API simplifies life for applications that always perform a write() immediately after a successful connect(). Such applications can now take advantage of Fast Open by merely making one new setsockopt() call at the time of creating the socket. Nothing else about the application's socket call sequence needs to change. Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-23 18:59:22 +00:00
case TCP_FASTOPEN_CONNECT:
if (val > 1 || val < 0) {
err = -EINVAL;
} else if (net->ipv4.sysctl_tcp_fastopen & TFO_CLIENT_ENABLE) {
net/tcp-fastopen: Add new API support This patch adds a new socket option, TCP_FASTOPEN_CONNECT, as an alternative way to perform Fast Open on the active side (client). Prior to this patch, a client needs to replace the connect() call with sendto(MSG_FASTOPEN). This can be cumbersome for applications who want to use Fast Open: these socket operations are often done in lower layer libraries used by many other applications. Changing these libraries and/or the socket call sequences are not trivial. A more convenient approach is to perform Fast Open by simply enabling a socket option when the socket is created w/o changing other socket calls sequence: s = socket() create a new socket setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT …); newly introduced sockopt If set, new functionality described below will be used. Return ENOTSUPP if TFO is not supported or not enabled in the kernel. connect() With cookie present, return 0 immediately. With no cookie, initiate 3WHS with TFO cookie-request option and return -1 with errno = EINPROGRESS. write()/sendmsg() With cookie present, send out SYN with data and return the number of bytes buffered. With no cookie, and 3WHS not yet completed, return -1 with errno = EINPROGRESS. No MSG_FASTOPEN flag is needed. read() Return -1 with errno = EWOULDBLOCK/EAGAIN if connect() is called but write() is not called yet. Return -1 with errno = EWOULDBLOCK/EAGAIN if connection is established but no msg is received yet. Return number of bytes read if socket is established and there is msg received. The new API simplifies life for applications that always perform a write() immediately after a successful connect(). Such applications can now take advantage of Fast Open by merely making one new setsockopt() call at the time of creating the socket. Nothing else about the application's socket call sequence needs to change. Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-23 18:59:22 +00:00
if (sk->sk_state == TCP_CLOSE)
tp->fastopen_connect = val;
else
err = -EINVAL;
} else {
err = -EOPNOTSUPP;
}
break;
case TCP_FASTOPEN_NO_COOKIE:
if (val > 1 || val < 0)
err = -EINVAL;
else if (!((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
err = -EINVAL;
else
tp->fastopen_no_cookie = val;
break;
case TCP_TIMESTAMP:
if (!tp->repair)
err = -EPERM;
else
tp->tsoffset = val - tcp_time_stamp_raw();
break;
case TCP_REPAIR_WINDOW:
err = tcp_repair_set_window(tp, optval, optlen);
break;
tcp: TCP_NOTSENT_LOWAT socket option Idea of this patch is to add optional limitation of number of unsent bytes in TCP sockets, to reduce usage of kernel memory. TCP receiver might announce a big window, and TCP sender autotuning might allow a large amount of bytes in write queue, but this has little performance impact if a large part of this buffering is wasted : Write queue needs to be large only to deal with large BDP, not necessarily to cope with scheduling delays (incoming ACKS make room for the application to queue more bytes) For most workloads, using a value of 128 KB or less is OK to give applications enough time to react to POLLOUT events in time (or being awaken in a blocking sendmsg()) This patch adds two ways to set the limit : 1) Per socket option TCP_NOTSENT_LOWAT 2) A sysctl (/proc/sys/net/ipv4/tcp_notsent_lowat) for sockets not using TCP_NOTSENT_LOWAT socket option (or setting a zero value) Default value being UINT_MAX (0xFFFFFFFF), meaning this has no effect. This changes poll()/select()/epoll() to report POLLOUT only if number of unsent bytes is below tp->nosent_lowat Note this might increase number of sendmsg()/sendfile() calls when using non blocking sockets, and increase number of context switches for blocking sockets. Note this is not related to SO_SNDLOWAT (as SO_SNDLOWAT is defined as : Specify the minimum number of bytes in the buffer until the socket layer will pass the data to the protocol) Tested: netperf sessions, and watching /proc/net/protocols "memory" column for TCP With 200 concurrent netperf -t TCP_STREAM sessions, amount of kernel memory used by TCP buffers shrinks by ~55 % (20567 pages instead of 45458) lpq83:~# echo -1 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# (super_netperf 200 -t TCP_STREAM -H remote -l 90 &); sleep 60 ; grep TCP /proc/net/protocols TCPv6 1880 2 45458 no 208 yes ipv6 y y y y y y y y y y y y y n y y y y y TCP 1696 508 45458 no 208 yes kernel y y y y y y y y y y y y y n y y y y y lpq83:~# echo 131072 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# (super_netperf 200 -t TCP_STREAM -H remote -l 90 &); sleep 60 ; grep TCP /proc/net/protocols TCPv6 1880 2 20567 no 208 yes ipv6 y y y y y y y y y y y y y n y y y y y TCP 1696 508 20567 no 208 yes kernel y y y y y y y y y y y y y n y y y y y Using 128KB has no bad effect on the throughput or cpu usage of a single flow, although there is an increase of context switches. A bonus is that we hold socket lock for a shorter amount of time and should improve latencies of ACK processing. lpq83:~# echo -1 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# perf stat -e context-switches ./netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3 OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : +/-2.500% @ 99% conf. Local Remote Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service Send Socket Recv Socket Send Time Units CPU CPU CPU CPU Service Service Demand Size Size Size (sec) Util Util Util Util Demand Demand Units Final Final % Method % Method 1651584 6291456 16384 20.00 17447.90 10^6bits/s 3.13 S -1.00 U 0.353 -1.000 usec/KB Performance counter stats for './netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3': 412,514 context-switches 200.034645535 seconds time elapsed lpq83:~# echo 131072 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# perf stat -e context-switches ./netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3 OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : +/-2.500% @ 99% conf. Local Remote Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service Send Socket Recv Socket Send Time Units CPU CPU CPU CPU Service Service Demand Size Size Size (sec) Util Util Util Util Demand Demand Units Final Final % Method % Method 1593240 6291456 16384 20.00 17321.16 10^6bits/s 3.35 S -1.00 U 0.381 -1.000 usec/KB Performance counter stats for './netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3': 2,675,818 context-switches 200.029651391 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-By: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-23 03:27:07 +00:00
case TCP_NOTSENT_LOWAT:
tp->notsent_lowat = val;
sk->sk_write_space(sk);
break;
tcp: send in-queue bytes in cmsg upon read Applications with many concurrent connections, high variance in receive queue length and tight memory bounds cannot allocate worst-case buffer size to drain sockets. Knowing the size of receive queue length, applications can optimize how they allocate buffers to read from the socket. The number of bytes pending on the socket is directly available through ioctl(FIONREAD/SIOCINQ) and can be approximated using getsockopt(MEMINFO) (rmem_alloc includes skb overheads in addition to application data). But, both of these options add an extra syscall per recvmsg. Moreover, ioctl(FIONREAD/SIOCINQ) takes the socket lock. Add the TCP_INQ socket option to TCP. When this socket option is set, recvmsg() relays the number of bytes available on the socket for reading to the application via the TCP_CM_INQ control message. Calculate the number of bytes after releasing the socket lock to include the processed backlog, if any. To avoid an extra branch in the hot path of recvmsg() for this new control message, move all cmsg processing inside an existing branch for processing receive timestamps. Since the socket lock is not held when calculating the size of receive queue, TCP_INQ is a hint. For example, it can overestimate the queue size by one byte, if FIN is received. With this method, applications can start reading from the socket using a small buffer, and then use larger buffers based on the remaining data when needed. V3 change-log: As suggested by David Miller, added loads with barrier to check whether we have multiple threads calling recvmsg in parallel. When that happens we lock the socket to calculate inq. V4 change-log: Removed inline from a static function. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 19:39:15 +00:00
case TCP_INQ:
if (val > 1 || val < 0)
err = -EINVAL;
else
tp->recvmsg_inq = val;
break;
default:
err = -ENOPROTOOPT;
break;
}
release_sock(sk);
return err;
}
int tcp_setsockopt(struct sock *sk, int level, int optname, char __user *optval,
unsigned int optlen)
{
const struct inet_connection_sock *icsk = inet_csk(sk);
if (level != SOL_TCP)
return icsk->icsk_af_ops->setsockopt(sk, level, optname,
optval, optlen);
return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
EXPORT_SYMBOL(tcp_setsockopt);
#ifdef CONFIG_COMPAT
int compat_tcp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen)
{
if (level != SOL_TCP)
return inet_csk_compat_setsockopt(sk, level, optname,
optval, optlen);
return do_tcp_setsockopt(sk, level, optname, optval, optlen);
}
EXPORT_SYMBOL(compat_tcp_setsockopt);
#endif
static void tcp_get_info_chrono_stats(const struct tcp_sock *tp,
struct tcp_info *info)
{
u64 stats[__TCP_CHRONO_MAX], total = 0;
enum tcp_chrono i;
for (i = TCP_CHRONO_BUSY; i < __TCP_CHRONO_MAX; ++i) {
stats[i] = tp->chrono_stat[i - 1];
if (i == tp->chrono_type)
stats[i] += tcp_jiffies32 - tp->chrono_start;
stats[i] *= USEC_PER_SEC / HZ;
total += stats[i];
}
info->tcpi_busy_time = total;
info->tcpi_rwnd_limited = stats[TCP_CHRONO_RWND_LIMITED];
info->tcpi_sndbuf_limited = stats[TCP_CHRONO_SNDBUF_LIMITED];
}
/* Return information about state of tcp endpoint in API format. */
void tcp_get_info(struct sock *sk, struct tcp_info *info)
{
const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
const struct inet_connection_sock *icsk = inet_csk(sk);
unsigned long rate;
u32 now;
u64 rate64;
bool slow;
memset(info, 0, sizeof(*info));
if (sk->sk_type != SOCK_STREAM)
return;
info->tcpi_state = inet_sk_state_load(sk);
/* Report meaningful fields for all TCP states, including listeners */
rate = READ_ONCE(sk->sk_pacing_rate);
rate64 = (rate != ~0UL) ? rate : ~0ULL;
info->tcpi_pacing_rate = rate64;
rate = READ_ONCE(sk->sk_max_pacing_rate);
rate64 = (rate != ~0UL) ? rate : ~0ULL;
info->tcpi_max_pacing_rate = rate64;
info->tcpi_reordering = tp->reordering;
info->tcpi_snd_cwnd = tp->snd_cwnd;
if (info->tcpi_state == TCP_LISTEN) {
/* listeners aliased fields :
* tcpi_unacked -> Number of children ready for accept()
* tcpi_sacked -> max backlog
*/
info->tcpi_unacked = sk->sk_ack_backlog;
info->tcpi_sacked = sk->sk_max_ack_backlog;
return;
}
slow = lock_sock_fast(sk);
info->tcpi_ca_state = icsk->icsk_ca_state;
info->tcpi_retransmits = icsk->icsk_retransmits;
info->tcpi_probes = icsk->icsk_probes_out;
info->tcpi_backoff = icsk->icsk_backoff;
if (tp->rx_opt.tstamp_ok)
info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
if (tcp_is_sack(tp))
info->tcpi_options |= TCPI_OPT_SACK;
if (tp->rx_opt.wscale_ok) {
info->tcpi_options |= TCPI_OPT_WSCALE;
info->tcpi_snd_wscale = tp->rx_opt.snd_wscale;
info->tcpi_rcv_wscale = tp->rx_opt.rcv_wscale;
}
if (tp->ecn_flags & TCP_ECN_OK)
info->tcpi_options |= TCPI_OPT_ECN;
if (tp->ecn_flags & TCP_ECN_SEEN)
info->tcpi_options |= TCPI_OPT_ECN_SEEN;
if (tp->syn_data_acked)
info->tcpi_options |= TCPI_OPT_SYN_DATA;
info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);
info->tcpi_snd_mss = tp->mss_cache;
info->tcpi_rcv_mss = icsk->icsk_ack.rcv_mss;
info->tcpi_unacked = tp->packets_out;
info->tcpi_sacked = tp->sacked_out;
info->tcpi_lost = tp->lost_out;
info->tcpi_retrans = tp->retrans_out;
now = tcp_jiffies32;
info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);
info->tcpi_pmtu = icsk->icsk_pmtu_cookie;
info->tcpi_rcv_ssthresh = tp->rcv_ssthresh;
tcp: switch rtt estimations to usec resolution Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 22:02:48 +00:00
info->tcpi_rtt = tp->srtt_us >> 3;
info->tcpi_rttvar = tp->mdev_us >> 2;
info->tcpi_snd_ssthresh = tp->snd_ssthresh;
info->tcpi_advmss = tp->advmss;
info->tcpi_rcv_rtt = tp->rcv_rtt_est.rtt_us >> 3;
info->tcpi_rcv_space = tp->rcvq_space.space;
info->tcpi_total_retrans = tp->total_retrans;
info->tcpi_bytes_acked = tp->bytes_acked;
info->tcpi_bytes_received = tp->bytes_received;
info->tcpi_notsent_bytes = max_t(int, 0, tp->write_seq - tp->snd_nxt);
tcp_get_info_chrono_stats(tp, info);
info->tcpi_segs_out = tp->segs_out;
info->tcpi_segs_in = tp->segs_in;
info->tcpi_min_rtt = tcp_min_rtt(tp);
tcp: Add RFC4898 tcpEStatsPerfDataSegsOut/In Per RFC4898, they count segments sent/received containing a positive length data segment (that includes retransmission segments carrying data). Unlike tcpi_segs_out/in, tcpi_data_segs_out/in excludes segments carrying no data (e.g. pure ack). The patch also updates the segs_in in tcp_fastopen_add_skb() so that segs_in >= data_segs_in property is kept. Together with retransmission data, tcpi_data_segs_out gives a better signal on the rxmit rate. v6: Rebase on the latest net-next v5: Eric pointed out that checking skb->len is still needed in tcp_fastopen_add_skb() because skb can carry a FIN without data. Hence, instead of open coding segs_in and data_segs_in, tcp_segs_in() helper is used. Comment is added to the fastopen case to explain why segs_in has to be reset and tcp_segs_in() has to be called before __skb_pull(). v4: Add comment to the changes in tcp_fastopen_add_skb() and also add remark on this case in the commit message. v3: Add const modifier to the skb parameter in tcp_segs_in() v2: Rework based on recent fix by Eric: commit a9d99ce28ed3 ("tcp: fix tcpi_segs_in after connection establishment") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Cc: Chris Rapier <rapier@psc.edu> Cc: Eric Dumazet <edumazet@google.com> Cc: Marcelo Ricardo Leitner <mleitner@redhat.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-03-14 17:52:15 +00:00
info->tcpi_data_segs_in = tp->data_segs_in;
info->tcpi_data_segs_out = tp->data_segs_out;
info->tcpi_delivery_rate_app_limited = tp->rate_app_limited ? 1 : 0;
rate64 = tcp_compute_delivery_rate(tp);
if (rate64)
info->tcpi_delivery_rate = rate64;
info->tcpi_delivered = tp->delivered;
info->tcpi_delivered_ce = tp->delivered_ce;
info->tcpi_bytes_sent = tp->bytes_sent;
info->tcpi_bytes_retrans = tp->bytes_retrans;
info->tcpi_dsack_dups = tp->dsack_dups;
info->tcpi_reord_seen = tp->reord_seen;
unlock_sock_fast(sk, slow);
}
EXPORT_SYMBOL_GPL(tcp_get_info);
static size_t tcp_opt_stats_get_size(void)
{
return
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BUSY */
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_RWND_LIMITED */
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_SNDBUF_LIMITED */
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DATA_SEGS_OUT */
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_TOTAL_RETRANS */
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_PACING_RATE */
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_DELIVERY_RATE */
nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_CWND */
nla_total_size(sizeof(u32)) + /* TCP_NLA_REORDERING */
nla_total_size(sizeof(u32)) + /* TCP_NLA_MIN_RTT */
nla_total_size(sizeof(u8)) + /* TCP_NLA_RECUR_RETRANS */
nla_total_size(sizeof(u8)) + /* TCP_NLA_DELIVERY_RATE_APP_LMT */
nla_total_size(sizeof(u32)) + /* TCP_NLA_SNDQ_SIZE */
nla_total_size(sizeof(u8)) + /* TCP_NLA_CA_STATE */
nla_total_size(sizeof(u32)) + /* TCP_NLA_SND_SSTHRESH */
nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED */
nla_total_size(sizeof(u32)) + /* TCP_NLA_DELIVERED_CE */
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_SENT */
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_RETRANS */
nla_total_size(sizeof(u32)) + /* TCP_NLA_DSACK_DUPS */
nla_total_size(sizeof(u32)) + /* TCP_NLA_REORD_SEEN */
nla_total_size(sizeof(u32)) + /* TCP_NLA_SRTT */
0;
}
struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *stats;
struct tcp_info info;
unsigned long rate;
u64 rate64;
stats = alloc_skb(tcp_opt_stats_get_size(), GFP_ATOMIC);
if (!stats)
return NULL;
tcp_get_info_chrono_stats(tp, &info);
nla_put_u64_64bit(stats, TCP_NLA_BUSY,
info.tcpi_busy_time, TCP_NLA_PAD);
nla_put_u64_64bit(stats, TCP_NLA_RWND_LIMITED,
info.tcpi_rwnd_limited, TCP_NLA_PAD);
nla_put_u64_64bit(stats, TCP_NLA_SNDBUF_LIMITED,
info.tcpi_sndbuf_limited, TCP_NLA_PAD);
nla_put_u64_64bit(stats, TCP_NLA_DATA_SEGS_OUT,
tp->data_segs_out, TCP_NLA_PAD);
nla_put_u64_64bit(stats, TCP_NLA_TOTAL_RETRANS,
tp->total_retrans, TCP_NLA_PAD);
rate = READ_ONCE(sk->sk_pacing_rate);
rate64 = (rate != ~0UL) ? rate : ~0ULL;
nla_put_u64_64bit(stats, TCP_NLA_PACING_RATE, rate64, TCP_NLA_PAD);
rate64 = tcp_compute_delivery_rate(tp);
nla_put_u64_64bit(stats, TCP_NLA_DELIVERY_RATE, rate64, TCP_NLA_PAD);
nla_put_u32(stats, TCP_NLA_SND_CWND, tp->snd_cwnd);
nla_put_u32(stats, TCP_NLA_REORDERING, tp->reordering);
nla_put_u32(stats, TCP_NLA_MIN_RTT, tcp_min_rtt(tp));
nla_put_u8(stats, TCP_NLA_RECUR_RETRANS, inet_csk(sk)->icsk_retransmits);
nla_put_u8(stats, TCP_NLA_DELIVERY_RATE_APP_LMT, !!tp->rate_app_limited);
nla_put_u32(stats, TCP_NLA_SND_SSTHRESH, tp->snd_ssthresh);
nla_put_u32(stats, TCP_NLA_DELIVERED, tp->delivered);
nla_put_u32(stats, TCP_NLA_DELIVERED_CE, tp->delivered_ce);
nla_put_u32(stats, TCP_NLA_SNDQ_SIZE, tp->write_seq - tp->snd_una);
nla_put_u8(stats, TCP_NLA_CA_STATE, inet_csk(sk)->icsk_ca_state);
nla_put_u64_64bit(stats, TCP_NLA_BYTES_SENT, tp->bytes_sent,
TCP_NLA_PAD);
nla_put_u64_64bit(stats, TCP_NLA_BYTES_RETRANS, tp->bytes_retrans,
TCP_NLA_PAD);
nla_put_u32(stats, TCP_NLA_DSACK_DUPS, tp->dsack_dups);
nla_put_u32(stats, TCP_NLA_REORD_SEEN, tp->reord_seen);
nla_put_u32(stats, TCP_NLA_SRTT, tp->srtt_us >> 3);
return stats;
}
static int do_tcp_getsockopt(struct sock *sk, int level,
int optname, char __user *optval, int __user *optlen)
{
struct inet_connection_sock *icsk = inet_csk(sk);
struct tcp_sock *tp = tcp_sk(sk);
struct net *net = sock_net(sk);
int val, len;
if (get_user(len, optlen))
return -EFAULT;
len = min_t(unsigned int, len, sizeof(int));
if (len < 0)
return -EINVAL;
switch (optname) {
case TCP_MAXSEG:
val = tp->mss_cache;
if (!val && ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)))
val = tp->rx_opt.user_mss;
if (tp->repair)
val = tp->rx_opt.mss_clamp;
break;
case TCP_NODELAY:
val = !!(tp->nonagle&TCP_NAGLE_OFF);
break;
case TCP_CORK:
val = !!(tp->nonagle&TCP_NAGLE_CORK);
break;
case TCP_KEEPIDLE:
val = keepalive_time_when(tp) / HZ;
break;
case TCP_KEEPINTVL:
val = keepalive_intvl_when(tp) / HZ;
break;
case TCP_KEEPCNT:
val = keepalive_probes(tp);
break;
case TCP_SYNCNT:
val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
break;
case TCP_LINGER2:
val = tp->linger2;
if (val >= 0)
val = (val ? : net->ipv4.sysctl_tcp_fin_timeout) / HZ;
break;
case TCP_DEFER_ACCEPT:
val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,
TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);
break;
case TCP_WINDOW_CLAMP:
val = tp->window_clamp;
break;
case TCP_INFO: {
struct tcp_info info;
if (get_user(len, optlen))
return -EFAULT;
tcp_get_info(sk, &info);
len = min_t(unsigned int, len, sizeof(info));
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &info, len))
return -EFAULT;
return 0;
}
case TCP_CC_INFO: {
const struct tcp_congestion_ops *ca_ops;
union tcp_cc_info info;
size_t sz = 0;
int attr;
if (get_user(len, optlen))
return -EFAULT;
ca_ops = icsk->icsk_ca_ops;
if (ca_ops && ca_ops->get_info)
sz = ca_ops->get_info(sk, ~0U, &attr, &info);
len = min_t(unsigned int, len, sz);
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &info, len))
return -EFAULT;
return 0;
}
case TCP_QUICKACK:
val = !icsk->icsk_ack.pingpong;
break;
case TCP_CONGESTION:
if (get_user(len, optlen))
return -EFAULT;
len = min_t(unsigned int, len, TCP_CA_NAME_MAX);
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, icsk->icsk_ca_ops->name, len))
return -EFAULT;
return 0;
case TCP_ULP:
if (get_user(len, optlen))
return -EFAULT;
len = min_t(unsigned int, len, TCP_ULP_NAME_MAX);
if (!icsk->icsk_ulp_ops) {
if (put_user(0, optlen))
return -EFAULT;
return 0;
}
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, icsk->icsk_ulp_ops->name, len))
return -EFAULT;
return 0;
case TCP_FASTOPEN_KEY: {
__u8 key[TCP_FASTOPEN_KEY_LENGTH];
struct tcp_fastopen_context *ctx;
if (get_user(len, optlen))
return -EFAULT;
rcu_read_lock();
ctx = rcu_dereference(icsk->icsk_accept_queue.fastopenq.ctx);
if (ctx)
memcpy(key, ctx->key, sizeof(key));
else
len = 0;
rcu_read_unlock();
len = min_t(unsigned int, len, sizeof(key));
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, key, len))
return -EFAULT;
return 0;
}
case TCP_THIN_LINEAR_TIMEOUTS:
val = tp->thin_lto;
break;
case TCP_THIN_DUPACK:
val = 0;
break;
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-27 19:13:28 +00:00
case TCP_REPAIR:
val = tp->repair;
break;
case TCP_REPAIR_QUEUE:
if (tp->repair)
val = tp->repair_queue;
else
return -EINVAL;
break;
case TCP_REPAIR_WINDOW: {
struct tcp_repair_window opt;
if (get_user(len, optlen))
return -EFAULT;
if (len != sizeof(opt))
return -EINVAL;
if (!tp->repair)
return -EPERM;
opt.snd_wl1 = tp->snd_wl1;
opt.snd_wnd = tp->snd_wnd;
opt.max_window = tp->max_window;
opt.rcv_wnd = tp->rcv_wnd;
opt.rcv_wup = tp->rcv_wup;
if (copy_to_user(optval, &opt, len))
return -EFAULT;
return 0;
}
case TCP_QUEUE_SEQ:
if (tp->repair_queue == TCP_SEND_QUEUE)
val = tp->write_seq;
else if (tp->repair_queue == TCP_RECV_QUEUE)
val = tp->rcv_nxt;
else
return -EINVAL;
break;
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-27 19:13:28 +00:00
case TCP_USER_TIMEOUT:
val = icsk->icsk_user_timeout;
tcp: Add TCP_USER_TIMEOUT socket option. This patch provides a "user timeout" support as described in RFC793. The socket option is also needed for the the local half of RFC5482 "TCP User Timeout Option". TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int, when > 0, to specify the maximum amount of time in ms that transmitted data may remain unacknowledged before TCP will forcefully close the corresponding connection and return ETIMEDOUT to the application. If 0 is given, TCP will continue to use the system default. Increasing the user timeouts allows a TCP connection to survive extended periods without end-to-end connectivity. Decreasing the user timeouts allows applications to "fail fast" if so desired. Otherwise it may take upto 20 minutes with the current system defaults in a normal WAN environment. The socket option can be made during any state of a TCP connection, but is only effective during the synchronized states of a connection (ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK). Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option, TCP_USER_TIMEOUT will overtake keepalive to determine when to close a connection due to keepalive failure. The option does not change in anyway when TCP retransmits a packet, nor when a keepalive probe will be sent. This option, like many others, will be inherited by an acceptor from its listener. Signed-off-by: H.K. Jerry Chu <hkchu@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-27 19:13:28 +00:00
break;
case TCP_FASTOPEN:
val = icsk->icsk_accept_queue.fastopenq.max_qlen;
break;
net/tcp-fastopen: Add new API support This patch adds a new socket option, TCP_FASTOPEN_CONNECT, as an alternative way to perform Fast Open on the active side (client). Prior to this patch, a client needs to replace the connect() call with sendto(MSG_FASTOPEN). This can be cumbersome for applications who want to use Fast Open: these socket operations are often done in lower layer libraries used by many other applications. Changing these libraries and/or the socket call sequences are not trivial. A more convenient approach is to perform Fast Open by simply enabling a socket option when the socket is created w/o changing other socket calls sequence: s = socket() create a new socket setsockopt(s, IPPROTO_TCP, TCP_FASTOPEN_CONNECT …); newly introduced sockopt If set, new functionality described below will be used. Return ENOTSUPP if TFO is not supported or not enabled in the kernel. connect() With cookie present, return 0 immediately. With no cookie, initiate 3WHS with TFO cookie-request option and return -1 with errno = EINPROGRESS. write()/sendmsg() With cookie present, send out SYN with data and return the number of bytes buffered. With no cookie, and 3WHS not yet completed, return -1 with errno = EINPROGRESS. No MSG_FASTOPEN flag is needed. read() Return -1 with errno = EWOULDBLOCK/EAGAIN if connect() is called but write() is not called yet. Return -1 with errno = EWOULDBLOCK/EAGAIN if connection is established but no msg is received yet. Return number of bytes read if socket is established and there is msg received. The new API simplifies life for applications that always perform a write() immediately after a successful connect(). Such applications can now take advantage of Fast Open by merely making one new setsockopt() call at the time of creating the socket. Nothing else about the application's socket call sequence needs to change. Signed-off-by: Wei Wang <weiwan@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-23 18:59:22 +00:00
case TCP_FASTOPEN_CONNECT:
val = tp->fastopen_connect;
break;
case TCP_FASTOPEN_NO_COOKIE:
val = tp->fastopen_no_cookie;
break;
case TCP_TIMESTAMP:
val = tcp_time_stamp_raw() + tp->tsoffset;
break;
tcp: TCP_NOTSENT_LOWAT socket option Idea of this patch is to add optional limitation of number of unsent bytes in TCP sockets, to reduce usage of kernel memory. TCP receiver might announce a big window, and TCP sender autotuning might allow a large amount of bytes in write queue, but this has little performance impact if a large part of this buffering is wasted : Write queue needs to be large only to deal with large BDP, not necessarily to cope with scheduling delays (incoming ACKS make room for the application to queue more bytes) For most workloads, using a value of 128 KB or less is OK to give applications enough time to react to POLLOUT events in time (or being awaken in a blocking sendmsg()) This patch adds two ways to set the limit : 1) Per socket option TCP_NOTSENT_LOWAT 2) A sysctl (/proc/sys/net/ipv4/tcp_notsent_lowat) for sockets not using TCP_NOTSENT_LOWAT socket option (or setting a zero value) Default value being UINT_MAX (0xFFFFFFFF), meaning this has no effect. This changes poll()/select()/epoll() to report POLLOUT only if number of unsent bytes is below tp->nosent_lowat Note this might increase number of sendmsg()/sendfile() calls when using non blocking sockets, and increase number of context switches for blocking sockets. Note this is not related to SO_SNDLOWAT (as SO_SNDLOWAT is defined as : Specify the minimum number of bytes in the buffer until the socket layer will pass the data to the protocol) Tested: netperf sessions, and watching /proc/net/protocols "memory" column for TCP With 200 concurrent netperf -t TCP_STREAM sessions, amount of kernel memory used by TCP buffers shrinks by ~55 % (20567 pages instead of 45458) lpq83:~# echo -1 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# (super_netperf 200 -t TCP_STREAM -H remote -l 90 &); sleep 60 ; grep TCP /proc/net/protocols TCPv6 1880 2 45458 no 208 yes ipv6 y y y y y y y y y y y y y n y y y y y TCP 1696 508 45458 no 208 yes kernel y y y y y y y y y y y y y n y y y y y lpq83:~# echo 131072 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# (super_netperf 200 -t TCP_STREAM -H remote -l 90 &); sleep 60 ; grep TCP /proc/net/protocols TCPv6 1880 2 20567 no 208 yes ipv6 y y y y y y y y y y y y y n y y y y y TCP 1696 508 20567 no 208 yes kernel y y y y y y y y y y y y y n y y y y y Using 128KB has no bad effect on the throughput or cpu usage of a single flow, although there is an increase of context switches. A bonus is that we hold socket lock for a shorter amount of time and should improve latencies of ACK processing. lpq83:~# echo -1 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# perf stat -e context-switches ./netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3 OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : +/-2.500% @ 99% conf. Local Remote Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service Send Socket Recv Socket Send Time Units CPU CPU CPU CPU Service Service Demand Size Size Size (sec) Util Util Util Util Demand Demand Units Final Final % Method % Method 1651584 6291456 16384 20.00 17447.90 10^6bits/s 3.13 S -1.00 U 0.353 -1.000 usec/KB Performance counter stats for './netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3': 412,514 context-switches 200.034645535 seconds time elapsed lpq83:~# echo 131072 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# perf stat -e context-switches ./netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3 OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : +/-2.500% @ 99% conf. Local Remote Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service Send Socket Recv Socket Send Time Units CPU CPU CPU CPU Service Service Demand Size Size Size (sec) Util Util Util Util Demand Demand Units Final Final % Method % Method 1593240 6291456 16384 20.00 17321.16 10^6bits/s 3.35 S -1.00 U 0.381 -1.000 usec/KB Performance counter stats for './netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3': 2,675,818 context-switches 200.029651391 seconds time elapsed Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-By: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-23 03:27:07 +00:00
case TCP_NOTSENT_LOWAT:
val = tp->notsent_lowat;
break;
tcp: send in-queue bytes in cmsg upon read Applications with many concurrent connections, high variance in receive queue length and tight memory bounds cannot allocate worst-case buffer size to drain sockets. Knowing the size of receive queue length, applications can optimize how they allocate buffers to read from the socket. The number of bytes pending on the socket is directly available through ioctl(FIONREAD/SIOCINQ) and can be approximated using getsockopt(MEMINFO) (rmem_alloc includes skb overheads in addition to application data). But, both of these options add an extra syscall per recvmsg. Moreover, ioctl(FIONREAD/SIOCINQ) takes the socket lock. Add the TCP_INQ socket option to TCP. When this socket option is set, recvmsg() relays the number of bytes available on the socket for reading to the application via the TCP_CM_INQ control message. Calculate the number of bytes after releasing the socket lock to include the processed backlog, if any. To avoid an extra branch in the hot path of recvmsg() for this new control message, move all cmsg processing inside an existing branch for processing receive timestamps. Since the socket lock is not held when calculating the size of receive queue, TCP_INQ is a hint. For example, it can overestimate the queue size by one byte, if FIN is received. With this method, applications can start reading from the socket using a small buffer, and then use larger buffers based on the remaining data when needed. V3 change-log: As suggested by David Miller, added loads with barrier to check whether we have multiple threads calling recvmsg in parallel. When that happens we lock the socket to calculate inq. V4 change-log: Removed inline from a static function. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Neal Cardwell <ncardwell@google.com> Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-01 19:39:15 +00:00
case TCP_INQ:
val = tp->recvmsg_inq;
break;
case TCP_SAVE_SYN:
val = tp->save_syn;
break;
case TCP_SAVED_SYN: {
if (get_user(len, optlen))
return -EFAULT;
lock_sock(sk);
if (tp->saved_syn) {
if (len < tp->saved_syn[0]) {
if (put_user(tp->saved_syn[0], optlen)) {
release_sock(sk);
return -EFAULT;
}
release_sock(sk);
return -EINVAL;
}
len = tp->saved_syn[0];
if (put_user(len, optlen)) {
release_sock(sk);
return -EFAULT;
}
if (copy_to_user(optval, tp->saved_syn + 1, len)) {
release_sock(sk);
return -EFAULT;
}
tcp_saved_syn_free(tp);
release_sock(sk);
} else {
release_sock(sk);
len = 0;
if (put_user(len, optlen))
return -EFAULT;
}
return 0;
}
tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive When adding tcp mmap() implementation, I forgot that socket lock had to be taken before current->mm->mmap_sem. syzbot eventually caught the bug. Since we can not lock the socket in tcp mmap() handler we have to split the operation in two phases. 1) mmap() on a tcp socket simply reserves VMA space, and nothing else. This operation does not involve any TCP locking. 2) getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) implements the transfert of pages from skbs to one VMA. This operation only uses down_read(&current->mm->mmap_sem) after holding TCP lock, thus solving the lockdep issue. This new implementation was suggested by Andy Lutomirski with great details. Benefits are : - Better scalability, in case multiple threads reuse VMAS (without mmap()/munmap() calls) since mmap_sem wont be write locked. - Better error recovery. The previous mmap() model had to provide the expected size of the mapping. If for some reason one part could not be mapped (partial MSS), the whole operation had to be aborted. With the tcp_zerocopy_receive struct, kernel can report how many bytes were successfuly mapped, and how many bytes should be read to skip the problematic sequence. - No more memory allocation to hold an array of page pointers. 16 MB mappings needed 32 KB for this array, potentially using vmalloc() :/ - skbs are freed while mmap_sem has been released Following patch makes the change in tcp_mmap tool to demonstrate one possible use of mmap() and setsockopt(... TCP_ZEROCOPY_RECEIVE ...) Note that memcg might require additional changes. Fixes: 93ab6cc69162 ("tcp: implement mmap() for zero copy receive") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Cc: linux-mm@kvack.org Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-27 15:58:08 +00:00
#ifdef CONFIG_MMU
case TCP_ZEROCOPY_RECEIVE: {
struct tcp_zerocopy_receive zc;
int err;
if (get_user(len, optlen))
return -EFAULT;
if (len != sizeof(zc))
return -EINVAL;
if (copy_from_user(&zc, optval, len))
return -EFAULT;
lock_sock(sk);
err = tcp_zerocopy_receive(sk, &zc);
release_sock(sk);
if (!err && copy_to_user(optval, &zc, len))
err = -EFAULT;
return err;
}
#endif
default:
return -ENOPROTOOPT;
}
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &val, len))
return -EFAULT;
return 0;
}
int tcp_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
int __user *optlen)
{
struct inet_connection_sock *icsk = inet_csk(sk);
if (level != SOL_TCP)
return icsk->icsk_af_ops->getsockopt(sk, level, optname,
optval, optlen);
return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
EXPORT_SYMBOL(tcp_getsockopt);
#ifdef CONFIG_COMPAT
int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
if (level != SOL_TCP)
return inet_csk_compat_getsockopt(sk, level, optname,
optval, optlen);
return do_tcp_getsockopt(sk, level, optname, optval, optlen);
}
EXPORT_SYMBOL(compat_tcp_getsockopt);
#endif
#ifdef CONFIG_TCP_MD5SIG
static DEFINE_PER_CPU(struct tcp_md5sig_pool, tcp_md5sig_pool);
static DEFINE_MUTEX(tcp_md5sig_mutex);
static bool tcp_md5sig_pool_populated = false;
static void __tcp_alloc_md5sig_pool(void)
{
struct crypto_ahash *hash;
int cpu;
hash = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto update from Herbert Xu: "Here is the crypto update for 4.6: API: - Convert remaining crypto_hash users to shash or ahash, also convert blkcipher/ablkcipher users to skcipher. - Remove crypto_hash interface. - Remove crypto_pcomp interface. - Add crypto engine for async cipher drivers. - Add akcipher documentation. - Add skcipher documentation. Algorithms: - Rename crypto/crc32 to avoid name clash with lib/crc32. - Fix bug in keywrap where we zero the wrong pointer. Drivers: - Support T5/M5, T7/M7 SPARC CPUs in n2 hwrng driver. - Add PIC32 hwrng driver. - Support BCM6368 in bcm63xx hwrng driver. - Pack structs for 32-bit compat users in qat. - Use crypto engine in omap-aes. - Add support for sama5d2x SoCs in atmel-sha. - Make atmel-sha available again. - Make sahara hashing available again. - Make ccp hashing available again. - Make sha1-mb available again. - Add support for multiple devices in ccp. - Improve DMA performance in caam. - Add hashing support to rockchip" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (116 commits) crypto: qat - remove redundant arbiter configuration crypto: ux500 - fix checks of error code returned by devm_ioremap_resource() crypto: atmel - fix checks of error code returned by devm_ioremap_resource() crypto: qat - Change the definition of icp_qat_uof_regtype hwrng: exynos - use __maybe_unused to hide pm functions crypto: ccp - Add abstraction for device-specific calls crypto: ccp - CCP versioning support crypto: ccp - Support for multiple CCPs crypto: ccp - Remove check for x86 family and model crypto: ccp - memset request context to zero during import lib/mpi: use "static inline" instead of "extern inline" lib/mpi: avoid assembler warning hwrng: bcm63xx - fix non device tree compatibility crypto: testmgr - allow rfc3686 aes-ctr variants in fips mode. crypto: qat - The AE id should be less than the maximal AE number lib/mpi: Endianness fix crypto: rockchip - add hash support for crypto engine in rk3288 crypto: xts - fix compile errors crypto: doc - add skcipher API documentation crypto: doc - update AEAD AD handling ...
2016-03-17 18:22:54 +00:00
if (IS_ERR(hash))
return;
for_each_possible_cpu(cpu) {
void *scratch = per_cpu(tcp_md5sig_pool, cpu).scratch;
struct ahash_request *req;
if (!scratch) {
scratch = kmalloc_node(sizeof(union tcp_md5sum_block) +
sizeof(struct tcphdr),
GFP_KERNEL,
cpu_to_node(cpu));
if (!scratch)
return;
per_cpu(tcp_md5sig_pool, cpu).scratch = scratch;
}
if (per_cpu(tcp_md5sig_pool, cpu).md5_req)
continue;
req = ahash_request_alloc(hash, GFP_KERNEL);
if (!req)
return;
ahash_request_set_callback(req, 0, NULL, NULL);
per_cpu(tcp_md5sig_pool, cpu).md5_req = req;
}
/* before setting tcp_md5sig_pool_populated, we must commit all writes
* to memory. See smp_rmb() in tcp_get_md5sig_pool()
*/
smp_wmb();
tcp_md5sig_pool_populated = true;
}
bool tcp_alloc_md5sig_pool(void)
{
if (unlikely(!tcp_md5sig_pool_populated)) {
mutex_lock(&tcp_md5sig_mutex);
if (!tcp_md5sig_pool_populated) {
__tcp_alloc_md5sig_pool();
if (tcp_md5sig_pool_populated)
static_key_slow_inc(&tcp_md5_needed);
}
mutex_unlock(&tcp_md5sig_mutex);
}
return tcp_md5sig_pool_populated;
}
EXPORT_SYMBOL(tcp_alloc_md5sig_pool);
/**
* tcp_get_md5sig_pool - get md5sig_pool for this user
*
* We use percpu structure, so if we succeed, we exit with preemption
* and BH disabled, to make sure another thread or softirq handling
* wont try to get same context.
*/
struct tcp_md5sig_pool *tcp_get_md5sig_pool(void)
{
local_bh_disable();
if (tcp_md5sig_pool_populated) {
/* coupled with smp_wmb() in __tcp_alloc_md5sig_pool() */
smp_rmb();
return this_cpu_ptr(&tcp_md5sig_pool);
}
local_bh_enable();
return NULL;
}
EXPORT_SYMBOL(tcp_get_md5sig_pool);
int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp,
const struct sk_buff *skb, unsigned int header_len)
{
struct scatterlist sg;
const struct tcphdr *tp = tcp_hdr(skb);
struct ahash_request *req = hp->md5_req;
unsigned int i;
const unsigned int head_data_len = skb_headlen(skb) > header_len ?
skb_headlen(skb) - header_len : 0;
const struct skb_shared_info *shi = skb_shinfo(skb);
struct sk_buff *frag_iter;
sg_init_table(&sg, 1);
sg_set_buf(&sg, ((u8 *) tp) + header_len, head_data_len);
ahash_request_set_crypt(req, &sg, NULL, head_data_len);
if (crypto_ahash_update(req))
return 1;
for (i = 0; i < shi->nr_frags; ++i) {
const struct skb_frag_struct *f = &shi->frags[i];
unsigned int offset = f->page_offset;
struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT);
sg_set_page(&sg, page, skb_frag_size(f),
offset_in_page(offset));
ahash_request_set_crypt(req, &sg, NULL, skb_frag_size(f));
if (crypto_ahash_update(req))
return 1;
}
skb_walk_frags(skb, frag_iter)
if (tcp_md5_hash_skb_data(hp, frag_iter, 0))
return 1;
return 0;
}
EXPORT_SYMBOL(tcp_md5_hash_skb_data);
int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, const struct tcp_md5sig_key *key)
{
struct scatterlist sg;
sg_init_one(&sg, key->key, key->keylen);
ahash_request_set_crypt(hp->md5_req, &sg, NULL, key->keylen);
return crypto_ahash_update(hp->md5_req);
}
EXPORT_SYMBOL(tcp_md5_hash_key);
#endif
void tcp_done(struct sock *sk)
{
struct request_sock *req = tcp_sk(sk)->fastopen_rsk;
if (sk->sk_state == TCP_SYN_SENT || sk->sk_state == TCP_SYN_RECV)
TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS);
tcp_set_state(sk, TCP_CLOSE);
tcp_clear_xmit_timers(sk);
if (req)
reqsk_fastopen_remove(sk, req, false);
sk->sk_shutdown = SHUTDOWN_MASK;
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_state_change(sk);
else
inet_csk_destroy_sock(sk);
}
EXPORT_SYMBOL_GPL(tcp_done);
int tcp_abort(struct sock *sk, int err)
{
if (!sk_fullsock(sk)) {
if (sk->sk_state == TCP_NEW_SYN_RECV) {
struct request_sock *req = inet_reqsk(sk);
local_bh_disable();
inet_csk_reqsk_queue_drop(req->rsk_listener, req);
local_bh_enable();
return 0;
}
return -EOPNOTSUPP;
}
/* Don't race with userspace socket closes such as tcp_close. */
lock_sock(sk);
if (sk->sk_state == TCP_LISTEN) {
tcp_set_state(sk, TCP_CLOSE);
inet_csk_listen_stop(sk);
}
/* Don't race with BH socket closes such as inet_csk_listen_stop. */
local_bh_disable();
bh_lock_sock(sk);
if (!sock_flag(sk, SOCK_DEAD)) {
sk->sk_err = err;
/* This barrier is coupled with smp_rmb() in tcp_poll() */
smp_wmb();
sk->sk_error_report(sk);
if (tcp_need_reset(sk->sk_state))
tcp_send_active_reset(sk, GFP_ATOMIC);
tcp_done(sk);
}
bh_unlock_sock(sk);
local_bh_enable();
tcp_write_queue_purge(sk);
release_sock(sk);
return 0;
}
EXPORT_SYMBOL_GPL(tcp_abort);
extern struct tcp_congestion_ops tcp_reno;
static __initdata unsigned long thash_entries;
static int __init set_thash_entries(char *str)
{
ssize_t ret;
if (!str)
return 0;
ret = kstrtoul(str, 0, &thash_entries);
if (ret)
return 0;
return 1;
}
__setup("thash_entries=", set_thash_entries);
static void __init tcp_init_mem(void)
{
unsigned long limit = nr_free_buffer_pages() / 16;
limit = max(limit, 128UL);
sysctl_tcp_mem[0] = limit / 4 * 3; /* 4.68 % */
sysctl_tcp_mem[1] = limit; /* 6.25 % */
sysctl_tcp_mem[2] = sysctl_tcp_mem[0] * 2; /* 9.37 % */
}
void __init tcp_init(void)
{
tcp: change tcp_adv_win_scale and tcp_rmem[2] tcp_adv_win_scale default value is 2, meaning we expect a good citizen skb to have skb->len / skb->truesize ratio of 75% (3/4) In 2.6 kernels we (mis)accounted for typical MSS=1460 frame : 1536 + 64 + 256 = 1856 'estimated truesize', and 1856 * 3/4 = 1392. So these skbs were considered as not bloated. With recent truesize fixes, a typical MSS=1460 frame truesize is now the more precise : 2048 + 256 = 2304. But 2304 * 3/4 = 1728. So these skb are not good citizen anymore, because 1460 < 1728 (GRO can escape this problem because it build skbs with a too low truesize.) This also means tcp advertises a too optimistic window for a given allocated rcvspace : When receiving frames, sk_rmem_alloc can hit sk_rcvbuf limit and we call tcp_prune_queue()/tcp_collapse() too often, especially when application is slow to drain its receive queue or in case of losses (netperf is fast, scp is slow). This is a major latency source. We should adjust the len/truesize ratio to 50% instead of 75% This patch : 1) changes tcp_adv_win_scale default to 1 instead of 2 2) increase tcp_rmem[2] limit from 4MB to 6MB to take into account better truesize tracking and to allow autotuning tcp receive window to reach same value than before. Note that same amount of kernel memory is consumed compared to 2.6 kernels. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-02 02:28:41 +00:00
int max_rshare, max_wshare, cnt;
unsigned long limit;
unsigned int i;
BUILD_BUG_ON(sizeof(struct tcp_skb_cb) >
FIELD_SIZEOF(struct sk_buff, cb));
percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
percpu_counter_init(&tcp_orphan_count, 0, GFP_KERNEL);
inet_hashinfo_init(&tcp_hashinfo);
inet_hashinfo2_init(&tcp_hashinfo, "tcp_listen_portaddr_hash",
thash_entries, 21, /* one slot per 2 MB*/
0, 64 * 1024);
tcp_hashinfo.bind_bucket_cachep =
kmem_cache_create("tcp_bind_bucket",
sizeof(struct inet_bind_bucket), 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
/* Size and allocate the main established and bind bucket
* hash tables.
*
* The methodology is similar to that of the buffer cache.
*/
tcp_hashinfo.ehash =
alloc_large_system_hash("TCP established",
sizeof(struct inet_ehash_bucket),
thash_entries,
17, /* one slot per 128 KB of memory */
0,
NULL,
&tcp_hashinfo.ehash_mask,
0,
[TCP]: Saner thash_entries default with much memory. On systems with a very large amount of memory, the heuristics in alloc_large_system_hash() result in a very large TCP established hash table: 16 millions of entries for a 128 GB ia64 system. This makes reading from /proc/net/tcp pretty slow (well over a second) and as a result netstat is slow on these machines. I know that /proc/net/tcp is deprecated in favor of tcp_diag, however at the moment netstat only knows of the former. I am skeptical that such a large TCP established hash is often needed. Just because a system has a lot of memory doesn't imply that it will have several millions of concurrent TCP connections. Thus I believe that we should put an arbitrary high limit to the size of the TCP established hash by default. Users who really need a bigger hash can always use the thash_entries boot parameter to get more. I propose 2 millions of entries as the arbitrary high limit. This makes /proc/net/tcp reasonably fast on the system in question (0.2 s) while being still large enough for me to be confident that network performance won't suffer. This is just one way to limit the hash size, there are others; I am not familiar enough with the TCP code to decide which is best. Thus, I would welcome the proposals of alternatives. [ 2 million is still too large, thus I've modified the limit in the change to be '512 * 1024'. -DaveM ] Signed-off-by: Jean Delvare <jdelvare@suse.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-30 07:59:25 +00:00
thash_entries ? 0 : 512 * 1024);
tcp/dccp: remove twchain TCP listener refactoring, part 3 : Our goal is to hash SYN_RECV sockets into main ehash for fast lookup, and parallel SYN processing. Current inet_ehash_bucket contains two chains, one for ESTABLISH (and friend states) sockets, another for TIME_WAIT sockets only. As the hash table is sized to get at most one socket per bucket, it makes little sense to have separate twchain, as it makes the lookup slightly more complicated, and doubles hash table memory usage. If we make sure all socket types have the lookup keys at the same offsets, we can use a generic and faster lookup. It turns out TIME_WAIT and ESTABLISHED sockets already have common lookup fields for IPv4. [ INET_TW_MATCH() is no longer needed ] I'll provide a follow-up to factorize IPv6 lookup as well, to remove INET6_TW_MATCH() This way, SYN_RECV pseudo sockets will be supported the same. A new sock_gen_put() helper is added, doing either a sock_put() or inet_twsk_put() [ and will support SYN_RECV later ]. Note this helper should only be called in real slow path, when rcu lookup found a socket that was moved to another identity (freed/reused immediately), but could eventually be used in other contexts, like sock_edemux() Before patch : dmesg | grep "TCP established" TCP established hash table entries: 524288 (order: 11, 8388608 bytes) After patch : TCP established hash table entries: 524288 (order: 10, 4194304 bytes) Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-03 07:22:02 +00:00
for (i = 0; i <= tcp_hashinfo.ehash_mask; i++)
INIT_HLIST_NULLS_HEAD(&tcp_hashinfo.ehash[i].chain, i);
tcp/dccp: remove twchain TCP listener refactoring, part 3 : Our goal is to hash SYN_RECV sockets into main ehash for fast lookup, and parallel SYN processing. Current inet_ehash_bucket contains two chains, one for ESTABLISH (and friend states) sockets, another for TIME_WAIT sockets only. As the hash table is sized to get at most one socket per bucket, it makes little sense to have separate twchain, as it makes the lookup slightly more complicated, and doubles hash table memory usage. If we make sure all socket types have the lookup keys at the same offsets, we can use a generic and faster lookup. It turns out TIME_WAIT and ESTABLISHED sockets already have common lookup fields for IPv4. [ INET_TW_MATCH() is no longer needed ] I'll provide a follow-up to factorize IPv6 lookup as well, to remove INET6_TW_MATCH() This way, SYN_RECV pseudo sockets will be supported the same. A new sock_gen_put() helper is added, doing either a sock_put() or inet_twsk_put() [ and will support SYN_RECV later ]. Note this helper should only be called in real slow path, when rcu lookup found a socket that was moved to another identity (freed/reused immediately), but could eventually be used in other contexts, like sock_edemux() Before patch : dmesg | grep "TCP established" TCP established hash table entries: 524288 (order: 11, 8388608 bytes) After patch : TCP established hash table entries: 524288 (order: 10, 4194304 bytes) Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-03 07:22:02 +00:00
if (inet_ehash_locks_alloc(&tcp_hashinfo))
panic("TCP: failed to alloc ehash_locks");
tcp_hashinfo.bhash =
alloc_large_system_hash("TCP bind",
sizeof(struct inet_bind_hashbucket),
tcp_hashinfo.ehash_mask + 1,
17, /* one slot per 128 KB of memory */
0,
&tcp_hashinfo.bhash_size,
NULL,
0,
64 * 1024);
tcp_hashinfo.bhash_size = 1U << tcp_hashinfo.bhash_size;
for (i = 0; i < tcp_hashinfo.bhash_size; i++) {
spin_lock_init(&tcp_hashinfo.bhash[i].lock);
INIT_HLIST_HEAD(&tcp_hashinfo.bhash[i].chain);
}
cnt = tcp_hashinfo.ehash_mask + 1;
sysctl_tcp_max_orphans = cnt / 2;
tcp_init_mem();
/* Set per-socket limits to no more than 1/128 the pressure threshold */
limit = nr_free_buffer_pages() << (PAGE_SHIFT - 7);
tcp: change tcp_adv_win_scale and tcp_rmem[2] tcp_adv_win_scale default value is 2, meaning we expect a good citizen skb to have skb->len / skb->truesize ratio of 75% (3/4) In 2.6 kernels we (mis)accounted for typical MSS=1460 frame : 1536 + 64 + 256 = 1856 'estimated truesize', and 1856 * 3/4 = 1392. So these skbs were considered as not bloated. With recent truesize fixes, a typical MSS=1460 frame truesize is now the more precise : 2048 + 256 = 2304. But 2304 * 3/4 = 1728. So these skb are not good citizen anymore, because 1460 < 1728 (GRO can escape this problem because it build skbs with a too low truesize.) This also means tcp advertises a too optimistic window for a given allocated rcvspace : When receiving frames, sk_rmem_alloc can hit sk_rcvbuf limit and we call tcp_prune_queue()/tcp_collapse() too often, especially when application is slow to drain its receive queue or in case of losses (netperf is fast, scp is slow). This is a major latency source. We should adjust the len/truesize ratio to 50% instead of 75% This patch : 1) changes tcp_adv_win_scale default to 1 instead of 2 2) increase tcp_rmem[2] limit from 4MB to 6MB to take into account better truesize tracking and to allow autotuning tcp receive window to reach same value than before. Note that same amount of kernel memory is consumed compared to 2.6 kernels. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-02 02:28:41 +00:00
max_wshare = min(4UL*1024*1024, limit);
max_rshare = min(6UL*1024*1024, limit);
init_net.ipv4.sysctl_tcp_wmem[0] = SK_MEM_QUANTUM;
init_net.ipv4.sysctl_tcp_wmem[1] = 16*1024;
init_net.ipv4.sysctl_tcp_wmem[2] = max(64*1024, max_wshare);
init_net.ipv4.sysctl_tcp_rmem[0] = SK_MEM_QUANTUM;
tcp: up initial rmem to 128KB and SYN rwin to around 64KB Previously TCP initial receive buffer is ~87KB by default and the initial receive window is ~29KB (20 MSS). This patch changes the two numbers to 128KB and ~64KB (rounding down to the multiples of MSS) respectively. The patch also simplifies the calculations s.t. the two numbers are directly controlled by sysctl tcp_rmem[1]: 1) Initial receiver buffer budget (sk_rcvbuf): while this should be configured via sysctl tcp_rmem[1], previously tcp_fixup_rcvbuf() always override and set a larger size when a new connection establishes. 2) Initial receive window in SYN: previously it is set to 20 packets if MSS <= 1460. The number 20 was based on the initial congestion window of 10: the receiver needs twice amount to avoid being limited by the receive window upon out-of-order delivery in the first window burst. But since this only applies if the receiving MSS <= 1460, connection using large MTU (e.g. to utilize receiver zero-copy) may be limited by the receive window. With this patch TCP memory configuration is more straight-forward and more properly sized to modern high-speed networks by default. Several popular stacks have been announcing 64KB rwin in SYNs as well. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Wei Wang <weiwan@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-09-27 18:21:19 +00:00
init_net.ipv4.sysctl_tcp_rmem[1] = 131072;
init_net.ipv4.sysctl_tcp_rmem[2] = max(131072, max_rshare);
pr_info("Hash tables configured (established %u bind %u)\n",
tcp_hashinfo.ehash_mask + 1, tcp_hashinfo.bhash_size);
tcp_v4_init();
tcp_metrics_init();
BUG_ON(tcp_register_congestion_control(&tcp_reno) != 0);
tcp: TCP Small Queues This introduce TSQ (TCP Small Queues) TSQ goal is to reduce number of TCP packets in xmit queues (qdisc & device queues), to reduce RTT and cwnd bias, part of the bufferbloat problem. sk->sk_wmem_alloc not allowed to grow above a given limit, allowing no more than ~128KB [1] per tcp socket in qdisc/dev layers at a given time. TSO packets are sized/capped to half the limit, so that we have two TSO packets in flight, allowing better bandwidth use. As a side effect, setting the limit to 40000 automatically reduces the standard gso max limit (65536) to 40000/2 : It can help to reduce latencies of high prio packets, having smaller TSO packets. This means we divert sock_wfree() to a tcp_wfree() handler, to queue/send following frames when skb_orphan() [2] is called for the already queued skbs. Results on my dev machines (tg3/ixgbe nics) are really impressive, using standard pfifo_fast, and with or without TSO/GSO. Without reduction of nominal bandwidth, we have reduction of buffering per bulk sender : < 1ms on Gbit (instead of 50ms with TSO) < 8ms on 100Mbit (instead of 132 ms) I no longer have 4 MBytes backlogged in qdisc by a single netperf session, and both side socket autotuning no longer use 4 Mbytes. As skb destructor cannot restart xmit itself ( as qdisc lock might be taken at this point ), we delegate the work to a tasklet. We use one tasklest per cpu for performance reasons. If tasklet finds a socket owned by the user, it sets TSQ_OWNED flag. This flag is tested in a new protocol method called from release_sock(), to eventually send new segments. [1] New /proc/sys/net/ipv4/tcp_limit_output_bytes tunable [2] skb_orphan() is usually called at TX completion time, but some drivers call it in their start_xmit() handler. These drivers should at least use BQL, or else a single TCP session can still fill the whole NIC TX ring, since TSQ will have no effect. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Dave Taht <dave.taht@bufferbloat.net> Cc: Tom Herbert <therbert@google.com> Cc: Matt Mathis <mattmathis@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-11 05:50:31 +00:00
tcp_tasklet_init();
}