linux/net/ipv4
Marcelo Ricardo Leitner 0b9aefea86 tcp: minimize false-positives on TCP/GRO check
Markus Trippelsdorf reported that after commit dcb17d22e1 ("tcp: warn
on bogus MSS and try to amend it") the kernel started logging the
warning for a NIC driver that doesn't even support GRO.

It was diagnosed that it was possibly caused on connections that were
using TCP Timestamps but some packets lacked the Timestamps option. As
we reduce rcv_mss when timestamps are used, the lack of them would cause
the packets to be bigger than expected, although this is a valid case.

As this warning is more as a hint, getting a clean-cut on the
threshold is probably not worth the execution time spent on it. This
patch thus alleviates the false-positives with 2 quick checks: by
accounting for the entire TCP option space and also checking against the
interface MTU if it's available.

These changes, specially the MTU one, might mask some real positives,
though if they are really happening, it's possible that sooner or later
it will be triggered anyway.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-03 18:43:41 -07:00
..
netfilter netfilter: nf_nat_snmp: Fix panic when snmp_trap_helper fails to register 2017-03-27 13:49:13 +02:00
af_inet.c net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
ah4.c IPsec: do not ignore crypto err in ah4 input 2017-01-16 12:57:48 +01:00
arp.c NET: Fix /proc/net/arp for AX.25 2017-02-13 22:15:03 -05:00
cipso_ipv4.c netlabel: out of bound access in cipso_v4_validate() 2017-02-04 19:44:22 -05:00
datagram.c net: Set sk_txhash from a random number 2015-07-29 22:44:04 -07:00
devinet.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
esp4_offload.c esp: Add a software GRO codepath 2017-02-15 11:04:11 +01:00
esp4.c esp: Introduce a helper to setup the trailer 2017-01-17 10:23:08 +01:00
fib_frontend.c ipv4: provide stronger user input validation in nl_fib_input() 2017-03-22 14:15:49 -07:00
fib_lookup.h
fib_rules.c switchdev: remove FIB offload infrastructure 2016-09-28 04:48:00 -04:00
fib_semantics.c ipv4: fib: Notify about nexthop status changes 2017-02-08 15:25:18 -05:00
fib_trie.c lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
fou.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-10-30 12:42:58 -04:00
gre_demux.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-06-30 05:03:36 -04:00
gre_offload.c net: add recursion limit to GRO 2016-10-20 14:32:22 -04:00
icmp.c net: for rate-limited ICMP replies save one atomic operation 2017-01-09 15:49:12 -05:00
igmp.c igmp, mld: Fix memory leak in igmpv3/mld_del_delrec() 2017-02-09 16:43:45 -05:00
inet_connection_sock.c net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
inet_diag.c tcp: remove early retransmit 2017-01-13 22:37:16 -05:00
inet_fragment.c net: disable fragment reassembly if high_thresh is zero 2016-06-05 22:56:42 -04:00
inet_hashtables.c inet: kill smallest_size and smallest_port 2017-01-18 13:04:29 -05:00
inet_timewait_sock.c ipv4: Namespaceify tcp_tw_recycle and tcp_max_tw_buckets knob 2016-12-29 11:38:31 -05:00
inetpeer.c net: Add helper function to compare inetpeer addresses 2015-08-28 13:32:36 -07:00
ip_forward.c ipv4: allow local fragmentation in ip_finish_output_gso() 2016-11-03 16:10:26 -04:00
ip_fragment.c inet: frag: release spinlock before calling icmp_send() 2017-03-22 15:40:45 -07:00
ip_gre.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
ip_input.c net: VRF: Pass original iif to ip_route_input() 2016-09-16 04:24:07 -04:00
ip_options.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
ip_output.c udp: avoid ufo handling on IP payload compression packets 2017-03-09 18:28:42 -08:00
ip_sockglue.c ip: fix IP_CHECKSUM handling 2017-02-21 12:23:53 -05:00
ip_tunnel_core.c lwtunnel: remove device arg to lwtunnel_build_state 2017-01-30 15:14:22 -05:00
ip_tunnel.c netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
ip_vti.c netns: make struct pernet_operations::id unsigned int 2016-11-18 10:59:15 -05:00
ipcomp.c
ipconfig.c net: ipconfig: fix ic_close_devs() use-after-free 2017-03-27 21:06:53 -07:00
ipip.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
ipmr.c lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
Kconfig Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2017-02-16 21:25:49 -05:00
Makefile esp: Add a software GRO codepath 2017-02-15 11:04:11 +01:00
netfilter.c netfilter: use skb_to_full_sk in ip_route_me_harder 2017-02-28 12:49:36 +01:00
ping.c ping: implement proper locking 2017-03-24 20:50:28 -07:00
proc.c net: add LINUX_MIB_PFMEMALLOCDROP counter 2017-02-02 23:34:19 -05:00
protocol.c
raw_diag.c net: ip, raw_diag -- Use jump for exiting from nested loop 2016-11-03 15:25:26 -04:00
raw.c net: use dst_confirm_neigh for UDP, RAW, ICMP, L2TP 2017-02-07 13:07:47 -05:00
route.c ipv4: mask tos for input route 2017-02-26 11:03:38 -05:00
syncookies.c syncookies: use SipHash in place of SHA1 2017-01-09 13:58:57 -05:00
sysctl_net_ipv4.c net: Avoid receiving packets with an l3mdev on unbound UDP sockets 2017-01-30 15:00:58 -05:00
tcp_bbr.c tcp_bbr: add a state transition diagram and accompanying comment 2016-10-29 17:12:43 -04:00
tcp_bic.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_cdg.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h> 2017-03-02 08:42:27 +01:00
tcp_cong.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-11-22 13:27:16 -05:00
tcp_cubic.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_dctcp.c Revert "dctcp: update cwnd on congestion event" 2016-12-06 11:34:24 -05:00
tcp_diag.c net: diag: Fix refcnt leak in error path destroying socket 2016-08-23 23:11:36 -07:00
tcp_fastopen.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-01-28 10:33:06 -05:00
tcp_highspeed.c tcp: add cwnd_undo functions to various tcp cc algorithms 2016-11-21 13:20:17 -05:00
tcp_htcp.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_hybla.c tcp: make undo_cwnd mandatory for congestion modules 2016-11-21 13:20:17 -05:00
tcp_illinois.c tcp: add cwnd_undo functions to various tcp cc algorithms 2016-11-21 13:20:17 -05:00
tcp_input.c tcp: minimize false-positives on TCP/GRO check 2017-04-03 18:43:41 -07:00
tcp_ipv4.c dccp/tcp: fix routing redirect race 2017-03-13 21:55:47 -07:00
tcp_lp.c tcp: make undo_cwnd mandatory for congestion modules 2016-11-21 13:20:17 -05:00
tcp_metrics.c tcp: replace dst_confirm with sk_dst_confirm 2017-02-07 13:07:46 -05:00
tcp_minisocks.c tcp: initialize icsk_ack.lrcvtime at session start time 2017-03-22 15:39:42 -07:00
tcp_nv.c tcp: add NV congestion control 2016-06-10 23:07:49 -07:00
tcp_offload.c gso: Support partial splitting at the frag_list pointer 2016-09-19 20:59:34 -04:00
tcp_output.c tcp: accommodate sequence number to a peer's shrunk receive window caused by precision loss in window scaling 2017-02-17 15:30:33 -05:00
tcp_probe.c tcp: Revert "tcp: tcp_probe: use spin_lock_bh()" 2017-02-21 13:26:03 -05:00
tcp_rate.c tcp: export data delivery rate 2016-09-21 00:23:00 -04:00
tcp_recovery.c tcp: enable RACK loss detection to trigger recovery 2017-01-13 22:37:16 -05:00
tcp_scalable.c tcp: add cwnd_undo functions to various tcp cc algorithms 2016-11-21 13:20:17 -05:00
tcp_timer.c tcp: fix various issues for sockets morphing to listen state 2017-03-07 13:58:33 -08:00
tcp_vegas.c tcp: make undo_cwnd mandatory for congestion modules 2016-11-21 13:20:17 -05:00
tcp_vegas.h tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_veno.c tcp: add cwnd_undo functions to various tcp cc algorithms 2016-11-21 13:20:17 -05:00
tcp_westwood.c tcp: make undo_cwnd mandatory for congestion modules 2016-11-21 13:20:17 -05:00
tcp_yeah.c tcp: add cwnd_undo functions to various tcp cc algorithms 2016-11-21 13:20:17 -05:00
tcp.c tcp: tcp_get_info() should read tcp_time_stamp later 2017-03-16 21:37:13 -07:00
tunnel4.c tunnels: correct conditional build of MPLS and IPv6 2016-07-11 13:27:06 -07:00
udp_diag.c net: inet: diag: expose the socket mark to privileged processes. 2016-09-08 16:13:09 -07:00
udp_impl.h udplite: call proper backlog handlers 2016-11-24 15:32:14 -05:00
udp_offload.c net: add recursion limit to GRO 2016-10-20 14:32:22 -04:00
udp_tunnel.c net: Remove deprecated tunnel specific UDP offload functions 2016-06-17 20:23:32 -07:00
udp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-02-07 16:29:30 -05:00
udplite.c udplite: call proper backlog handlers 2016-11-24 15:32:14 -05:00
xfrm4_input.c esp: Add a software GRO codepath 2017-02-15 11:04:11 +01:00
xfrm4_mode_beet.c
xfrm4_mode_transport.c esp: Add a software GRO codepath 2017-02-15 11:04:11 +01:00
xfrm4_mode_tunnel.c
xfrm4_output.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-10-24 06:54:12 -07:00
xfrm4_policy.c xfrm: policy: make policy backend const 2017-02-09 10:22:19 +01:00
xfrm4_protocol.c xfrm: input: constify xfrm_input_afinfo 2017-02-09 10:22:17 +01:00
xfrm4_state.c xfrm: remove unused function 2017-01-10 10:57:12 +01:00
xfrm4_tunnel.c