Commit Graph

81 Commits

Author SHA1 Message Date
Alexander Sverdlin
29c4afc4e9 sctp: Fix race between OOTB responce and route removal
There is NULL pointer dereference possible during statistics update if the route
used for OOTB responce is removed at unfortunate time. If the route exists when
we receive OOTB packet and we finally jump into sctp_packet_transmit() to send
ABORT, but in the meantime route is removed under our feet, we take "no_route"
path and try to update stats with IP_INC_STATS(sock_net(asoc->base.sk), ...).

But sctp_ootb_pkt_new() used to prepare responce packet doesn't call
sctp_transport_set_owner() and therefore there is no asoc associated with this
packet. Probably temporary asoc just for OOTB responces is overkill, so just
introduce a check like in all other places in sctp_packet_transmit(), where
"asoc" is dereferenced.

To reproduce this, one needs to
0. ensure that sctp module is loaded (otherwise ABORT is not generated)
1. remove default route on the machine
2. while true; do
     ip route del [interface-specific route]
     ip route add [interface-specific route]
   done
3. send enough OOTB packets (i.e. HB REQs) from another host to trigger ABORT
   responce

On x86_64 the crash looks like this:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: [<ffffffffa05ec9ac>] sctp_packet_transmit+0x63c/0x730 [sctp]
PGD 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: ...
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G           O    4.0.5-1-ARCH #1
Hardware name: ...
task: ffffffff818124c0 ti: ffffffff81800000 task.ti: ffffffff81800000
RIP: 0010:[<ffffffffa05ec9ac>]  [<ffffffffa05ec9ac>] sctp_packet_transmit+0x63c/0x730 [sctp]
RSP: 0018:ffff880127c037b8  EFLAGS: 00010296
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000015ff66b480
RDX: 00000015ff66b400 RSI: ffff880127c17200 RDI: ffff880123403700
RBP: ffff880127c03888 R08: 0000000000017200 R09: ffffffff814625af
R10: ffffea00047e4680 R11: 00000000ffffff80 R12: ffff8800b0d38a28
R13: ffff8800b0d38a28 R14: ffff8800b3e88000 R15: ffffffffa05f24e0
FS:  0000000000000000(0000) GS:ffff880127c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000020 CR3: 00000000c855b000 CR4: 00000000000007f0
Stack:
 ffff880127c03910 ffff8800b0d38a28 ffffffff8189d240 ffff88011f91b400
 ffff880127c03828 ffffffffa05c94c5 0000000000000000 ffff8800baa1c520
 0000000000000000 0000000000000001 0000000000000000 0000000000000000
Call Trace:
 <IRQ>
 [<ffffffffa05c94c5>] ? sctp_sf_tabort_8_4_8.isra.20+0x85/0x140 [sctp]
 [<ffffffffa05d6b42>] ? sctp_transport_put+0x52/0x80 [sctp]
 [<ffffffffa05d0bfc>] sctp_do_sm+0xb8c/0x19a0 [sctp]
 [<ffffffff810b0e00>] ? trigger_load_balance+0x90/0x210
 [<ffffffff810e0329>] ? update_process_times+0x59/0x60
 [<ffffffff812c7a40>] ? timerqueue_add+0x60/0xb0
 [<ffffffff810e0549>] ? enqueue_hrtimer+0x29/0xa0
 [<ffffffff8101f599>] ? read_tsc+0x9/0x10
 [<ffffffff8116d4b5>] ? put_page+0x55/0x60
 [<ffffffff810ee1ad>] ? clockevents_program_event+0x6d/0x100
 [<ffffffff81462b68>] ? skb_free_head+0x58/0x80
 [<ffffffffa029a10b>] ? chksum_update+0x1b/0x27 [crc32c_generic]
 [<ffffffff81283f3e>] ? crypto_shash_update+0xce/0xf0
 [<ffffffffa05d3993>] sctp_endpoint_bh_rcv+0x113/0x280 [sctp]
 [<ffffffffa05dd4e6>] sctp_inq_push+0x46/0x60 [sctp]
 [<ffffffffa05ed7a0>] sctp_rcv+0x880/0x910 [sctp]
 [<ffffffffa05ecb50>] ? sctp_packet_transmit_chunk+0xb0/0xb0 [sctp]
 [<ffffffffa05ecb70>] ? sctp_csum_update+0x20/0x20 [sctp]
 [<ffffffff814b05a5>] ? ip_route_input_noref+0x235/0xd30
 [<ffffffff81051d6b>] ? ack_ioapic_level+0x7b/0x150
 [<ffffffff814b27be>] ip_local_deliver_finish+0xae/0x210
 [<ffffffff814b2e15>] ip_local_deliver+0x35/0x90
 [<ffffffff814b2a15>] ip_rcv_finish+0xf5/0x370
 [<ffffffff814b3128>] ip_rcv+0x2b8/0x3a0
 [<ffffffff81474193>] __netif_receive_skb_core+0x763/0xa50
 [<ffffffff81476c28>] __netif_receive_skb+0x18/0x60
 [<ffffffff81476cb0>] netif_receive_skb_internal+0x40/0xd0
 [<ffffffff814776c8>] napi_gro_receive+0xe8/0x120
 [<ffffffffa03946aa>] rtl8169_poll+0x2da/0x660 [r8169]
 [<ffffffff8147896a>] net_rx_action+0x21a/0x360
 [<ffffffff81078dc1>] __do_softirq+0xe1/0x2d0
 [<ffffffff8107912d>] irq_exit+0xad/0xb0
 [<ffffffff8157d158>] do_IRQ+0x58/0xf0
 [<ffffffff8157b06d>] common_interrupt+0x6d/0x6d
 <EOI>
 [<ffffffff810e1218>] ? hrtimer_start+0x18/0x20
 [<ffffffffa05d65f9>] ? sctp_transport_destroy_rcu+0x29/0x30 [sctp]
 [<ffffffff81020c50>] ? mwait_idle+0x60/0xa0
 [<ffffffff810216ef>] arch_cpu_idle+0xf/0x20
 [<ffffffff810b731c>] cpu_startup_entry+0x3ec/0x480
 [<ffffffff8156b365>] rest_init+0x85/0x90
 [<ffffffff818eb035>] start_kernel+0x48b/0x4ac
 [<ffffffff818ea120>] ? early_idt_handlers+0x120/0x120
 [<ffffffff818ea339>] x86_64_start_reservations+0x2a/0x2c
 [<ffffffff818ea49c>] x86_64_start_kernel+0x161/0x184
Code: 90 48 8b 80 b8 00 00 00 48 89 85 70 ff ff ff 48 83 bd 70 ff ff ff 00 0f 85 cd fa ff ff 48 89 df 31 db e8 18 63 e7 e0 48 8b 45 80 <48> 8b 40 20 48 8b 40 30 48 8b 80 68 01 00 00 65 48 ff 40 78 e9
RIP  [<ffffffffa05ec9ac>] sctp_packet_transmit+0x63c/0x730 [sctp]
 RSP <ffff880127c037b8>
CR2: 0000000000000020
---[ end trace 5aec7fd2dc983574 ]---
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffff9fffffff)
drm_kms_helper: panic occurred, switching back to text console
---[ end Kernel panic - not syncing: Fatal exception in interrupt

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-29 09:28:42 -07:00
Daniel Borkmann
9772b54c55 net: sctp: use MAX_HEADER for headroom reserve in output path
To accomodate for enough headroom for tunnels, use MAX_HEADER instead
of LL_MAX_HEADER. Robert reported that he has hit after roughly 40hrs
of trinity an skb_under_panic() via SCTP output path (see reference).
I couldn't reproduce it from here, but not using MAX_HEADER as elsewhere
in other protocols might be one possible cause for this.

In any case, it looks like accounting on chunks themself seems to look
good as the skb already passed the SCTP output path and did not hit
any skb_over_panic(). Given tunneling was enabled in his .config, the
headroom would have been expanded by MAX_HEADER in this case.

Reported-by: Robert Święcki <robert@swiecki.net>
Reference: https://lkml.org/lkml/2014/12/1/507
Fixes: 594ccc14df ("[SCTP] Replace incorrect use of dev_alloc_skb with alloc_skb in sctp_packet_transmit().")
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-09 13:24:03 -05:00
David S. Miller
d247b6ab3c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/Makefile
	net/ipv6/sysctl_net_ipv6.c

Two ipv6_table_template[] additions overlap, so the index
of the ipv6_table[x] assignments needed to be adjusted.

In the drivers/net/Makefile case, we've gotten rid of the
garbage whereby we had to list every single USB networking
driver in the top-level Makefile, there is just one
"USB_NETWORKING" that guards everything.

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 18:46:26 -07:00
Eric Dumazet
757efd32d5 sctp: fix possible seqlock seadlock in sctp_packet_transmit()
Dave reported following splat, caused by improper use of
IP_INC_STATS_BH() in process context.

BUG: using __this_cpu_add() in preemptible [00000000] code: trinity-c117/14551
caller is __this_cpu_preempt_check+0x13/0x20
CPU: 3 PID: 14551 Comm: trinity-c117 Not tainted 3.16.0+ #33
 ffffffff9ec898f0 0000000047ea7e23 ffff88022d32f7f0 ffffffff9e7ee207
 0000000000000003 ffff88022d32f818 ffffffff9e397eaa ffff88023ee70b40
 ffff88022d32f970 ffff8801c026d580 ffff88022d32f828 ffffffff9e397ee3
Call Trace:
 [<ffffffff9e7ee207>] dump_stack+0x4e/0x7a
 [<ffffffff9e397eaa>] check_preemption_disabled+0xfa/0x100
 [<ffffffff9e397ee3>] __this_cpu_preempt_check+0x13/0x20
 [<ffffffffc0839872>] sctp_packet_transmit+0x692/0x710 [sctp]
 [<ffffffffc082a7f2>] sctp_outq_flush+0x2a2/0xc30 [sctp]
 [<ffffffff9e0d985c>] ? mark_held_locks+0x7c/0xb0
 [<ffffffff9e7f8c6d>] ? _raw_spin_unlock_irqrestore+0x5d/0x80
 [<ffffffffc082b99a>] sctp_outq_uncork+0x1a/0x20 [sctp]
 [<ffffffffc081e112>] sctp_cmd_interpreter.isra.23+0x1142/0x13f0 [sctp]
 [<ffffffffc081c86b>] sctp_do_sm+0xdb/0x330 [sctp]
 [<ffffffff9e0b8f1b>] ? preempt_count_sub+0xab/0x100
 [<ffffffffc083b350>] ? sctp_cname+0x70/0x70 [sctp]
 [<ffffffffc08389ca>] sctp_primitive_ASSOCIATE+0x3a/0x50 [sctp]
 [<ffffffffc083358f>] sctp_sendmsg+0x88f/0xe30 [sctp]
 [<ffffffff9e0d673a>] ? lock_release_holdtime.part.28+0x9a/0x160
 [<ffffffff9e0d62ce>] ? put_lock_stats.isra.27+0xe/0x30
 [<ffffffff9e73b624>] inet_sendmsg+0x104/0x220
 [<ffffffff9e73b525>] ? inet_sendmsg+0x5/0x220
 [<ffffffff9e68ac4e>] sock_sendmsg+0x9e/0xe0
 [<ffffffff9e1c0c09>] ? might_fault+0xb9/0xc0
 [<ffffffff9e1c0bae>] ? might_fault+0x5e/0xc0
 [<ffffffff9e68b234>] SYSC_sendto+0x124/0x1c0
 [<ffffffff9e0136b0>] ? syscall_trace_enter+0x250/0x330
 [<ffffffff9e68c3ce>] SyS_sendto+0xe/0x10
 [<ffffffff9e7f9be4>] tracesys+0xdd/0xe2

This is a followup of commits f1d8cba61c ("inet: fix possible
seqlock deadlocks") and 7f88c6b23a ("ipv6: fix possible seqlock
deadlock in ip6_finish_output2")

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Reported-by: Dave Jones <davej@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-05 16:42:55 -07:00
David Laight
526cbef778 net: sctp: Rename SCTP_XMIT_NAGLE_DELAY to SCTP_XMIT_DELAY
MSG_MORE and 'corking' a socket would require that the transmit of
a data chunk be delayed.
Rename the return value to be less specific.

Signed-off-by: David Laight <david.laight@aculab.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-22 13:32:11 -07:00
David Laight
723189faca net: sctp: Open out the check for Nagle
The check for Nagle contains 6 separate checks all of which must be true
before a data packet is delayed.
Separate out each into its own 'if (test) return SCTP_XMIT_OK' so that
the reasons can be individually described.

Also return directly with SCTP_XMIT_RWND_FULL.
Delete the now-unused 'retval' variable and 'finish' label from
sctp_packet_can_append_data().

Signed-off-by: David Laight <david.laight@aculab.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-22 13:32:10 -07:00
WANG Cong
60ff746739 net: rename local_df to ignore_df
As suggested by several people, rename local_df to ignore_df,
since it means "ignore df bit if it is set".

Cc: Maciej Żenczykowski <maze@google.com>
Cc: Florian Westphal <fw@strlen.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-12 14:03:41 -04:00
wangweidong
0438816efd sctp: move skb_dst_set() a bit downwards in sctp_packet_transmit()
skb_dst_set will use dst, if dst is NULL although is not a problem,
then goto the 'no_route' and free nskb, so do the skb_dst_set is pointless.
so move the skb_dst_set after dst check.
Remove the unnecessary initialization as well.

v2: fix the subject line because it would confuse people,
    as pointed out by Daniel.

Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-31 14:31:44 -05:00
wangweidong
f7010e6144 sctp: fix checkpatch errors with indent
fix checkpatch errors below:
ERROR: switch and case should be at the same inden
ERROR: code indent should use tabs where possible

Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-26 13:47:48 -05:00
wangweidong
131334d09c sctp: remove casting from function calls through ops structure
remove the unnecessary cast.

Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-22 18:04:28 -05:00
David S. Miller
143c905494 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/ethernet/intel/i40e/i40e_main.c
	drivers/net/macvtap.c

Both minor merge hassles, simple overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-18 16:42:06 -05:00
Neil Horman
9f70f46bd4 sctp: properly latch and use autoclose value from sock to association
Currently, sctp associations latch a sockets autoclose value to an association
at association init time, subject to capping constraints from the max_autoclose
sysctl value.  This leads to an odd situation where an application may set a
socket level autoclose timeout, but sliently sctp will limit the autoclose
timeout to something less than that.

Fix this by modifying the autoclose setsockopt function to check the limit, cap
it and warn the user via syslog that the timeout is capped.  This will allow
getsockopt to return valid autoclose timeout values that reflect what subsequent
associations actually use.

While were at it, also elimintate the assoc->autoclose variable, it duplicates
whats in the timeout array, which leads to multiple sources for the same
information, that may differ (as the former isn't subject to any capping).  This
gives us the timeout information in a canonical place and saves some space in
the association structure as well.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
CC: Wang Weidong <wangweidong1@huawei.com>
CC: David Miller <davem@davemloft.net>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-10 22:41:26 -05:00
Jeff Kirsher
4b2f13a251 sctp: Fix FSF address in file headers
Several files refer to an old address for the Free Software Foundation
in the file header comment.  Resolve by replacing the address with
the URL <http://www.gnu.org/licenses/> so that we do not have to keep
updating the header comments anytime the address changes.

CC: Vlad Yasevich <vyasevich@gmail.com>
CC: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-06 12:37:56 -05:00
Xufeng Zhang
6eabca54d6 sctp: Restore 'resent' bit to avoid retransmitted chunks for RTT measurements
Currently retransmitted DATA chunks could also be used for
RTT measurements since there are no flag to identify whether
the transmitted DATA chunk is a new one or a retransmitted one.
This problem is introduced by commit ae19c5486 ("sctp: remove
'resent' bit from the chunk") which inappropriately removed the
'resent' bit completely, instead of doing this, we should set
the resent bit only for the retransmitted DATA chunks.

Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-28 18:29:58 -05:00
Daniel Borkmann
e6d8b64b34 net: sctp: fix and consolidate SCTP checksumming code
This fixes an outstanding bug found through IPVS, where SCTP packets
with skb->data_len > 0 (non-linearized) and empty frag_list, but data
accumulated in frags[] member, are forwarded with incorrect checksum
letting SCTP initial handshake fail on some systems. Linearizing each
SCTP skb in IPVS to prevent that would not be a good solution as
this leads to an additional and unnecessary performance penalty on
the load-balancer itself for no good reason (as we actually only want
to update the checksum, and can do that in a different/better way
presented here).

The actual problem is elsewhere, namely, that SCTP's checksumming
in sctp_compute_cksum() does not take frags[] into account like
skb_checksum() does. So while we are fixing this up, we better reuse
the existing code that we have anyway in __skb_checksum() and use it
for walking through the data doing checksumming. This will not only
fix this issue, but also consolidates some SCTP code with core
sk_buff code, bringing it closer together and removing respectively
avoiding reimplementation of skb_checksum() for no good reason.

As crc32c() can use hardware implementation within the crypto layer,
we leave that intact (it wraps around / falls back to e.g. slice-by-8
algorithm in __crc32c_le() otherwise); plus use the __crc32c_le_combine()
combinator for crc32c blocks.

Also, we remove all other SCTP checksumming code, so that we only
have to use sctp_compute_cksum() from now on; for doing that, we need
to transform SCTP checkumming in output path slightly, and can leave
the rest intact.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-03 23:04:57 -05:00
Vlad Yasevich
d2dbbba77e sctp: Perform software checksum if packet has to be fragmented.
IP/IPv6 fragmentation knows how to compute only TCP/UDP checksum.
This causes problems if SCTP packets has to be fragmented and
ipsummed has been set to PARTIAL due to checksum offload support.
This condition can happen when retransmitting after MTU discover,
or when INIT or other control chunks are larger then MTU.
Check for the rare fragmentation condition in SCTP and use software
checksum calculation in this case.

CC: Fan Du <fan.du@windriver.com>
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-17 15:24:44 -04:00
Fan Du
27127a8256 sctp: Use software crc32 checksum when xfrm transform will happen.
igb/ixgbe have hardware sctp checksum support, when this feature is enabled
and also IPsec is armed to protect sctp traffic, ugly things happened as
xfrm_output checks CHECKSUM_PARTIAL to do checksum operation(sum every thing
up and pack the 16bits result in the checksum field). The result is fail
establishment of sctp communication.

Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Fan Du <fan.du@windriver.com>
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-17 15:24:44 -04:00
David S. Miller
71acc0ddd4 Revert "net: sctp: convert sctp_checksum_disable module param into sctp sysctl"
This reverts commit cda5f98e36.

As per Vlad's request.

Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-09 13:09:41 -07:00
Daniel Borkmann
477143e3fe net: sctp: trivial: update bug report in header comment
With the restructuring of the lksctp.org site, we only allow bug
reports through the SCTP mailing list linux-sctp@vger.kernel.org,
not via SF, as SF is only used for web hosting and nothing more.
While at it, also remove the obvious statement that bugs will be
fixed and incooperated into the kernel.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-09 11:33:02 -07:00
Daniel Borkmann
cda5f98e36 net: sctp: convert sctp_checksum_disable module param into sctp sysctl
Get rid of the last module parameter for SCTP and make this
configurable via sysctl for SCTP like all the rest of SCTP's
configuration knobs.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-09 11:33:02 -07:00
Daniel Borkmann
91705c61b5 net: sctp: trivial: update mailing list address
The SCTP mailing list address to send patches or questions
to is linux-sctp@vger.kernel.org and not
lksctp-developers@lists.sourceforge.net anymore. Therefore,
update all occurences.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-24 17:53:38 -07:00
Daniel Borkmann
bb33381d0c net: sctp: rework debugging framework to use pr_debug and friends
We should get rid of all own SCTP debug printk macros and use the ones
that the kernel offers anyway instead. This makes the code more readable
and conform to the kernel code, and offers all the features of dynamic
debbuging that pr_debug() et al has, such as only turning on/off portions
of debug messages at runtime through debugfs. The runtime cost of having
CONFIG_DYNAMIC_DEBUG enabled, but none of the debug statements printing,
is negligible [1]. If kernel debugging is completly turned off, then these
statements will also compile into "empty" functions.

While we're at it, we also need to change the Kconfig option as it /now/
only refers to the ifdef'ed code portions in outqueue.c that enable further
debugging/tracing of SCTP transaction fields. Also, since SCTP_ASSERT code
was enabled with this Kconfig option and has now been removed, we
transform those code parts into WARNs resp. where appropriate BUG_ONs so
that those bugs can be more easily detected as probably not many people
have SCTP debugging permanently turned on.

To turn on all SCTP debugging, the following steps are needed:

 # mount -t debugfs none /sys/kernel/debug
 # echo -n 'module sctp +p' > /sys/kernel/debug/dynamic_debug/control

This can be done more fine-grained on a per file, per line basis and others
as described in [2].

 [1] https://www.kernel.org/doc/ols/2009/ols2009-pages-39-46.pdf
 [2] Documentation/dynamic-debug-howto.txt

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-01 23:22:13 -07:00
Daniel Borkmann
3e3251b3f2 net: sctp: minor: remove dead code from sctp_packet
struct sctp_packet is currently embedded into sctp_transport or
sits on the stack as 'singleton' in sctp_outq_flush(). Therefore,
its member 'malloced' is always 0, thus a kfree() is never called.
Because of that, we can just remove this code.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-22 16:25:21 -04:00
Michele Baldessari
196d675934 sctp: Add support to per-association statistics via a new SCTP_GET_ASSOC_STATS call
The current SCTP stack is lacking a mechanism to have per association
statistics. This is an implementation modeled after OpenSolaris'
SCTP_GET_ASSOC_STATS.

Userspace part will follow on lksctp if/when there is a general ACK on
this.
V4:
- Move ipackets++ before q->immediate.func() for consistency reasons
- Move sctp_max_rto() at the end of sctp_transport_update_rto() to avoid
  returning bogus RTO values
- return asoc->rto_min when max_obs_rto value has not changed

V3:
- Increase ictrlchunks in sctp_assoc_bh_rcv() as well
- Move ipackets++ to sctp_inq_push()
- return 0 when no rto updates took place since the last call

V2:
- Implement partial retrieval of stat struct to cope for future expansion
- Kill the rtxpackets counter as it cannot be precise anyway
- Rename outseqtsns to outofseqtsns to make it clearer that these are out
  of sequence unexpected TSNs
- Move asoc->ipackets++ under a lock to avoid potential miscounts
- Fold asoc->opackets++ into the already existing asoc check
- Kill unneeded (q->asoc) test when increasing rtxchunks
- Do not count octrlchunks if sending failed (SCTP_XMIT_OK != 0)
- Don't count SHUTDOWNs as SACKs
- Move SCTP_GET_ASSOC_STATS to the private space API
- Adjust the len check in sctp_getsockopt_assoc_stats() to allow for
  future struct growth
- Move association statistics in their own struct
- Update idupchunks when we send a SACK with dup TSNs
- return min_rto in max_rto when RTO has not changed. Also return the
  transport when max_rto last changed.

Signed-off: Michele Baldessari <michele@acksyn.org>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-12-03 13:32:15 -05:00
David S. Miller
b48b63a1f6 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	net/netfilter/nfnetlink_log.c
	net/netfilter/xt_LOG.c

Rather easy conflict resolution, the 'net' tree had bug fixes to make
sure we checked if a socket is a time-wait one or not and elide the
logging code if so.

Whereas on the 'net-next' side we are calculating the UID and GID from
the creds using different interfaces due to the user namespace changes
from Eric Biederman.

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-15 11:43:53 -04:00
Thomas Graf
4c3a5bdae2 sctp: Don't charge for data in sndbuf again when transmitting packet
SCTP charges wmem_alloc via sctp_set_owner_w() in sctp_sendmsg() and via
skb_set_owner_w() in sctp_packet_transmit(). If a sender runs out of
sndbuf it will sleep in sctp_wait_for_sndbuf() and expects to be waken up
by __sctp_write_space().

Buffer space charged via sctp_set_owner_w() is released in sctp_wfree()
which calls __sctp_write_space() directly.

Buffer space charged via skb_set_owner_w() is released via sock_wfree()
which calls sk->sk_write_space() _if_ SOCK_USE_WRITE_QUEUE is not set.
sctp_endpoint_init() sets SOCK_USE_WRITE_QUEUE on all sockets.

Therefore if sctp_packet_transmit() manages to queue up more than sndbuf
bytes, sctp_wait_for_sndbuf() will never be woken up again unless it is
interrupted by a signal.

This could be fixed by clearing the SOCK_USE_WRITE_QUEUE flag but ...

Charging for the data twice does not make sense in the first place, it
leads to overcharging sndbuf by a factor 2. Therefore this patch only
charges a single byte in wmem_alloc when transmitting an SCTP packet to
ensure that the socket stays alive until the packet has been released.

This means that control chunks are no longer accounted for in wmem_alloc
which I believe is not a problem as skb->truesize will typically lead
to overcharging anyway and thus compensates for any control overhead.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
CC: Vlad Yasevich <vyasevic@redhat.com>
CC: Neil Horman <nhorman@tuxdriver.com>
CC: David Miller <davem@davemloft.net>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-09-03 13:24:13 -04:00
Eric W. Biederman
b01a24078f sctp: Make the mib per network namespace
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-14 23:30:36 -07:00
David S. Miller
02f3d4ce9e sctp: Adjust PMTU updates to accomodate route invalidation.
This adjusts the call to dst_ops->update_pmtu() so that we can
transparently handle the fact that, in the future, the dst itself can
be invalidated by the PMTU update (when we have non-host routes cached
in sockets).

Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-16 03:57:14 -07:00
Neil Horman
ed10627725 sctp: refactor sctp_packet_append_chunk and clenup some memory leaks
While doing some recent work on sctp sack bundling I noted that
sctp_packet_append_chunk was pretty inefficient.  Specifially, it was called
recursively while trying to bundle auth and sack chunks.  Because of that we
call sctp_packet_bundle_sack and sctp_packet_bundle_auth a total of 4 times for
every call to sctp_packet_append_chunk, knowing that at least 3 of those calls
will do nothing.

So lets refactor sctp_packet_bundle_auth to have an outer part that does the
attempted bundling, and an inner part that just does the chunk appends.  This
saves us several calls per iteration that we just don't need.

Also, noticed that the auth and sack bundling fail to free the chunks they
allocate if the append fails, so make sure we add that in

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: linux-sctp@vger.kernel.org
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-08 23:56:16 -07:00
Neil Horman
4244854d22 sctp: be more restrictive in transport selection on bundled sacks
It was noticed recently that when we send data on a transport, its possible that
we might bundle a sack that arrived on a different transport.  While this isn't
a major problem, it does go against the SHOULD requirement in section 6.4 of RFC
2960:

 An endpoint SHOULD transmit reply chunks (e.g., SACK, HEARTBEAT ACK,
   etc.) to the same destination transport address from which it
   received the DATA or control chunk to which it is replying.  This
   rule should also be followed if the endpoint is bundling DATA chunks
   together with the reply chunk.

This patch seeks to correct that.  It restricts the bundling of sack operations
to only those transports which have moved the ctsn of the association forward
since the last sack.  By doing this we guarantee that we only bundle outbound
saks on a transport that has received a chunk since the last sack.  This brings
us into stricter compliance with the RFC.

Vlad had initially suggested that we strictly allow only sack bundling on the
transport that last moved the ctsn forward.  While this makes sense, I was
concerned that doing so prevented us from bundling in the case where we had
received chunks that moved the ctsn on multiple transports.  In those cases, the
RFC allows us to select any of the transports having received chunks to bundle
the sack on.  so I've modified the approach to allow for that, by adding a state
variable to each transport that tracks weather it has moved the ctsn since the
last sack.  This I think keeps our behavior (and performance), close enough to
our current profile that I think we can do this without a sysctl knob to
enable/disable it.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Vlad Yaseivch <vyasevich@gmail.com>
CC: David S. Miller <davem@davemloft.net>
CC: linux-sctp@vger.kernel.org
Reported-by: Michele Baldessari <michele@redhat.com>
Reported-by: sorin serban <sserban@redhat.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-06-30 22:44:35 -07:00
David S. Miller
028940342a Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-05-16 22:17:37 -04:00
Nicolas Dichtel
e0268868ba sctp: check cached dst before using it
dst_check() will take care of SA (and obsolete field), hence
IPsec rekeying scenario is taken into account.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Vlad Yaseivch <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-10 23:15:47 -04:00
Eric Dumazet
95c9617472 net: cleanup unsigned to unsigned int
Use of "unsigned int" is preferred to bare "unsigned" in net tree.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-15 12:44:40 -04:00
Thomas Graf
a76c0adf60 sctp: Do not account for sizeof(struct sk_buff) in estimated rwnd
When checking whether a DATA chunk fits into the estimated rwnd a
full sizeof(struct sk_buff) is added to the needed chunk size. This
quickly exhausts the available rwnd space and leads to packets being
sent which are much below the PMTU limit. This can lead to much worse
performance.

The reason for this behaviour was to avoid putting too much memory
pressure on the receiver. The concept is not completely irational
because a Linux receiver does in fact clone an skb for each DATA chunk
delivered. However, Linux also reserves half the available socket
buffer space for data structures therefore usage of it is already
accounted for.

When proposing to change this the last time it was noted that this
behaviour was introduced to solve a performance issue caused by rwnd
overusage in combination with small DATA chunks.

Trying to reproduce this I found that with the sk_buff overhead removed,
the performance would improve significantly unless socket buffer limits
are increased.

The following numbers have been gathered using a patched iperf
supporting SCTP over a live 1 Gbit ethernet network. The -l option
was used to limit DATA chunk sizes. The numbers listed are based on
the average of 3 test runs each. Default values have been used for
sk_(r|w)mem.

Chunk
Size    Unpatched     No Overhead
-------------------------------------
   4    15.2 Kbit [!]   12.2 Mbit [!]
   8    35.8 Kbit [!]   26.0 Mbit [!]
  16    95.5 Kbit [!]   54.4 Mbit [!]
  32   106.7 Mbit      102.3 Mbit
  64   189.2 Mbit      188.3 Mbit
 128   331.2 Mbit      334.8 Mbit
 256   537.7 Mbit      536.0 Mbit
 512   766.9 Mbit      766.6 Mbit
1024   810.1 Mbit      808.6 Mbit

Signed-off-by: Thomas Graf <tgraf@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-12-20 13:58:37 -05:00
Michał Mirosław
b73c43f884 net: sctp: fix checksum marking for outgoing packets
Packets to devices without NETIF_F_SCTP_CSUM (including NETIF_F_NO_CSUM)
should be properly checksummed because the packets can be diverted or
rerouted after construction. This still leaves packets diverted from
NETIF_F_SCTP_CSUM-enabled devices with broken checksums. Fixing this
needs implementing software offload fallback in networking core.

For users of sctp_checksum_disable, skb->ip_summed should be left as
CHECKSUM_NONE and not CHECKSUM_UNNECESSARY as per include/linux/skbuff.h.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-07-14 15:16:31 -07:00
Lucas De Marchi
25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
David S. Miller
e40051d134 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
	drivers/net/qlcnic/qlcnic_init.c
	net/ipv4/ip_output.c
2010-09-27 01:03:03 -07:00
Vlad Yasevich
4bdab43323 sctp: Do not reset the packet during sctp_packet_config().
sctp_packet_config() is called when getting the packet ready
for appending of chunks.  The function should not touch the
current state, since it's possible to ping-pong between two
transports when sending, and that can result packet corruption
followed by skb overlfow crash.

Reported-by: Thomas Dreibholz <dreibh@iem.uni-due.de>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-09-17 16:47:56 -07:00
Joe Perches
145ce502e4 net/sctp: Use pr_fmt and pr_<level>
Change SCTP_DEBUG_PRINTK and SCTP_DEBUG_PRINTK_IPADDR to
use do { print } while (0) guards.
Add SCTP_DEBUG_PRINTK_CONT to fix errors in log when
lines were continued.
Add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
Add a missing newline in "Failed bind hash alloc"

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-26 14:11:48 -07:00
Vlad Yasevich
0e3aef8d09 sctp: Tag messages that can be Nagle delayed at creation.
When we create the sctp_datamsg and fragment the user data,
we know exactly if we are sending full segments or not and
how they might be bundled.  During this time, we can mark
messages a Nagle capable or not.  This makes the check at
transmit time much simpler.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2010-04-30 22:41:10 -04:00
Vlad Yasevich
ae19c54866 sctp: remove 'resent' bit from the chunk
The 'resent' bit is used to make sure that we don't update
rto estimate based on retransmitted chunks.  However, we already
have the 'rto_pending' bit that we test when need to update rto,
so 'resent' bit is just extra.  Additionally, we currently have
a bug in that we always set a 'resent' bit and thus rto estimate
is only updated by Heartbeats.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2010-04-30 22:41:09 -04:00
Tejun Heo
5a0e3ad6af 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>
2010-03-30 22:02:32 +09:00
Neil Horman
d8dd15781d sctp: Fix mis-ordering of user space data when multihoming in use
Recently had a bug reported to me, in which the user was sending
packets with a payload containing a sequence number.  The packets
were getting delivered in order according the chunk TSN values, but
the sequence values in the payload were arriving out of order.  At
first I thought it must be an application error, but we eventually
found it to be a problem on the transmit side in the sctp stack.

The conditions for the error are that multihoming must be in use,
and it helps if each transport has a different pmtu.  The problem
occurs in sctp_outq_flush.  Basically we dequeue packets from the
data queue, and attempt to append them to the orrered packet for a
given transport.  After we append a data chunk we add the trasport
to the end of a list of transports to have their packets sent at
the end of sctp_outq_flush.  The problem occurs when a data chunks
fills up a offered packet on a transport.  The function that does
the appending (sctp_packet_transmit_chunk), will try to call
sctp_packet_transmit on the full packet, and then append the chunk
to a new packet.  This call to sctp_packet_transmit, sends that
packet ahead of the others that may be queued in the transport_list
in sctp_outq_flush.  The result is that frames that were sent in one
order from the user space sending application get re-ordered prior
to tsn assignment in sctp_packet_transmit, resulting in mis-sequencing
of data payloads, even though tsn ordering is correct.

The fix is to change where we assign a tsn.  By doing this earlier,
we are then free to place chunks in packets, whatever way we
see fit and the protocol will make sure to do all the appropriate
re-ordering on receive as is needed.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: William Reich <reich@ulticom.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-11-23 15:54:00 -05:00
Vlad Yasevich
46d5a80855 sctp: Update max.burst implementation
Current implementation of max.burst ends up limiting new
data during cwnd decay period.  The decay is happening becuase
the connection is idle and we are allowed to fill the congestion
window.  The point of max.burst is to limit micro-bursts in response
to large acks.  This still happens, as max.burst is still applied
to each transmit opportunity.  It will also apply if a very large
send is made (greater then allowed by burst).

Tested-by: Florian Niederbacher <florian.niederbacher@student.uibk.ac.at>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-11-23 15:54:00 -05:00
Vlad Yasevich
245cba7e55 sctp: Remove useless last_time_used variable
The transport last_time_used variable is rather useless.
It was only used when determining if CWND needs to be updated
due to idle transport.  However, idle transport detection was
based on a Heartbeat timer and last_time_used was not incremented
when sending Heartbeats.  As a result the check for cwnd reduction
was always true.  We can get rid of the variable and just base
our cwnd manipulation on the HB timer (like the code comment sais).
We also have to call into the cwnd manipulation function regardless
of whether HBs are enabled or not.  That way we will detect idle
transports if the user has disabled Heartbeats.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-11-23 15:53:58 -05:00
Wei Yongjun
be2971438d sctp: remove dup code in net/sctp/output.c
Use sctp_packet_reset() instead of dup code.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-09-04 18:21:02 -04:00
Vlad Yasevich
4007cc88ce sctp: Correctly track if AUTH has been bundled.
We currently track if AUTH has been bundled using the 'auth'
pointer to the chunk.  However, AUTH is disallowed after DATA
is already in the packet, so we need to instead use the
'has_auth' field.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-09-04 18:21:00 -04:00
Wei Yongjun
d521c08f4c sctp: fix to reset packet information after packet transmit
The packet information does not reset after packet transmit, this
may cause some problems such as following DATA chunk be sent without
AUTH chunk, even if the authentication of DATA chunk has been
requested by the peer.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-09-04 18:21:00 -04:00
Vlad Yasevich
cb95ea32a4 sctp: Don't do NAGLE delay on large writes that were fragmented small
SCTP will delay the last part of a large write due to NAGLE, if that
part is smaller then MTU.  Since we are doing large writes, we might
as well send the last portion now instead of waiting untill the next
large write happens.  The small portion will be sent as is regardless,
so it's better to not delay it.

This is a result of much discussions with Wei Yongjun <yjwei@cn.fujitsu.com>
and Doug Graham <dgraham@nortel.com>.  Many thanks go out to them.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-09-04 18:20:59 -04:00
Vlad Yasevich
b29e790728 sctp: Nagle delay should be based on path mtu
The decision to delay due to Nagle should be based on the path mtu
and future packet size.  We currently incorrectly base it on
'frag_point' which is the SCTP DATA segment size, and also we do
not count DATA chunk header overhead in the computation.  This
actuall allows situations where a user can set low 'frag_point',
and then send small messages without delay.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
2009-09-04 18:20:59 -04:00