linux/net/ipv4
Marcelo Ricardo Leitner dcb17d22e1 tcp: warn on bogus MSS and try to amend it
There have been some reports lately about TCP connection stalls caused
by NIC drivers that aren't setting gso_size on aggregated packets on rx
path. This causes TCP to assume that the MSS is actually the size of the
aggregated packet, which is invalid.

Although the proper fix is to be done at each driver, it's often hard
and cumbersome for one to debug, come to such root cause and report/fix
it.

This patch amends this situation in two ways. First, it adds a warning
on when this situation occurs, so it gives a hint to those trying to
debug this. It also limit the maximum probed MSS to the adverised MSS,
as it should never be any higher than that.

The result is that the connection may not have the best performance ever
but it shouldn't stall, and the admin will have a hint on what to look
for.

Tested with virtio by forcing gso_size to 0.

v2: updated msg per David's suggestion
v3: use skb_iif to find the interface and also log its name, per Eric
    Dumazet's suggestion. As the skb may be backlogged and the interface
    gone by then, we need to check if the number still has a meaning.
v4: use helper tcp_gro_dev_warn() and avoid pr_warn_once inside __once, per
    David's suggestion

Cc: Jonathan Maxwell <jmaxwell37@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-06 11:01:19 -05:00
..
netfilter netfilter: arp_tables: fix invoking 32bit "iptable -P INPUT ACCEPT" failed in 64bit kernel 2016-11-30 20:50:23 +01:00
Kconfig tcp: Set DEFAULT_TCP_CONG to bbr if DEFAULT_BBR is set 2016-11-28 12:15:00 -05:00
Makefile tcp_bbr: add BBR congestion control 2016-09-21 00:23:01 -04:00
af_inet.c GSO: Reload iph after pskb_may_pull 2016-11-29 20:45:54 -05:00
ah4.c ah4: Fix error return in ah_input(). 2015-08-25 13:38:50 -07:00
arp.c net: rename NET_{ADD|INC}_STATS_BH() 2016-04-27 22:48:24 -04:00
cipso_ipv4.c Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/selinux into next 2016-07-07 10:15:34 +10:00
datagram.c net: Set sk_txhash from a random number 2015-07-29 22:44:04 -07:00
devinet.c netconf: add a notif when settings are created 2016-09-01 15:18:08 -07:00
esp4.c esp4: Fix integrity verification when ESN are used 2016-11-30 11:09:39 +01:00
fib_frontend.c ipv4: Restore fib_trie_flush_external function and fix call ordering 2016-11-16 13:24:50 -05:00
fib_lookup.h ipv4: consider TOS in fib_select_default 2015-07-24 22:46:11 -07:00
fib_rules.c switchdev: remove FIB offload infrastructure 2016-09-28 04:48:00 -04:00
fib_semantics.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-09-12 15:52:44 -07:00
fib_trie.c ipv4: Drop suffix update from resize code 2016-12-05 13:15:58 -05:00
fou.c net: add recursion limit to GRO 2016-10-20 14:32:22 -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: icmp_route_lookup should use rt dev to determine L3 domain 2016-11-09 18:49:39 -05:00
igmp.c igmp: do not remove igmp souce list info when set link down 2016-11-15 19:51:16 -05:00
inet_connection_sock.c timers, net/ipv4/inet: Initialize connection request timers as pinned 2016-07-07 10:35:06 +02:00
inet_diag.c net: inet: diag: expose the socket mark to privileged processes. 2016-09-08 16:13:09 -07:00
inet_fragment.c net: disable fragment reassembly if high_thresh is zero 2016-06-05 22:56:42 -04:00
inet_hashtables.c net: Require exact match for TCP socket lookups if dif is l3mdev 2016-10-17 10:17:05 -04:00
inet_timewait_sock.c timers, net/ipv4/inet: Initialize connection request timers as pinned 2016-07-07 10:35:06 +02:00
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 net: rename IP_INC_STATS_BH() 2016-04-27 22:48:23 -04:00
ip_gre.c net/ip_tunnels: Introduce tunnel_id_to_key32() and key32_to_tunnel_id() 2016-09-10 20:53:55 -07:00
ip_input.c net: VRF: Pass original iif to ip_route_input() 2016-09-16 04:24:07 -04:00
ip_options.c net: ipv4: Convert IP network timestamps to be y2038 safe 2016-03-01 17:18:44 -05:00
ip_output.c ipv4: Set skb->protocol properly for local output 2016-12-02 12:34:22 -05:00
ip_sockglue.c udp: fix IP_CHECKSUM handling 2016-10-26 17:33:22 -04:00
ip_tunnel.c ip_tunnel: add collect_md mode to IPIP tunnel 2016-09-17 10:13:07 -04:00
ip_tunnel_core.c ipv4: allow local fragmentation in ip_finish_output_gso() 2016-11-03 16:10:26 -04:00
ip_vti.c vti: use right inner_mode for inbound inter address family policy checks 2016-09-09 09:02:08 +02:00
ipcomp.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
ipconfig.c net: ipconfig: Fix NULL pointer dereference on RARP/BOOTP/DHCP timeout 2016-08-22 21:04:41 -07:00
ipip.c ip_tunnel: add collect_md mode to IPIP tunnel 2016-09-17 10:13:07 -04:00
ipmr.c ipv4: allow local fragmentation in ip_finish_output_gso() 2016-11-03 16:10:26 -04:00
netfilter.c netfilter: Update ip_route_me_harder to consider L3 domain 2016-11-24 12:44:36 +01:00
ping.c net: ping: check minimum size on ICMP header length 2016-12-05 13:35:38 -05:00
proc.c net: Suppress the "Comparison to NULL could be written" warnings 2016-09-30 01:50:45 -04:00
protocol.c net: Export inet_offloads and inet6_offloads 2014-09-19 17:15:31 -04:00
raw.c udp: must lock the socket in udp_disconnect() 2016-10-20 14:45:52 -04:00
route.c ipv4: use new_gw for redirect neigh lookup 2016-11-13 12:24:44 -05:00
syncookies.c net: rename NET_{ADD|INC}_STATS_BH() 2016-04-27 22:48:24 -04:00
sysctl_net_ipv4.c ipv4: use the right lock for ping_group_range 2016-10-22 16:23:12 -04:00
tcp.c tcp: fix return value for partial writes 2016-11-03 16:12:06 -04:00
tcp_bbr.c tcp_bbr: add BBR congestion control 2016-09-21 00:23:01 -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 tcp: cdg: rename struct minmax in tcp_cdg.c to avoid a naming conflict 2016-09-21 00:22:59 -04:00
tcp_cong.c tcp: zero ca_priv area when switching cc algorithms 2016-11-21 13:13:56 -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 dctcp: avoid bogus doubling of cwnd after loss 2016-10-31 15:16:28 -04:00
tcp_diag.c net: diag: Fix refcnt leak in error path destroying socket 2016-08-23 23:11:36 -07:00
tcp_fastopen.c tcp: fastopen: avoid negative sk_forward_alloc 2016-09-08 16:08:10 -07:00
tcp_highspeed.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_htcp.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_hybla.c tcp: do not slow start when cwnd equals ssthresh 2015-07-09 14:22:52 -07:00
tcp_illinois.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_input.c tcp: warn on bogus MSS and try to amend it 2016-12-06 11:01:19 -05:00
tcp_ipv4.c tcp: take care of truncations done by sk_filter() 2016-11-13 12:30:02 -05:00
tcp_lp.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_metrics.c tcp: make nla_policy const 2016-09-01 14:09:01 -07:00
tcp_minisocks.c tcp: track application-limited rate samples 2016-09-21 00:23:00 -04:00
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 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-10-02 22:20:41 -04:00
tcp_probe.c net: ipv4: tcp_probe: Replace timespec with timespec64 2016-03-01 17:18:44 -05:00
tcp_rate.c tcp: export data delivery rate 2016-09-21 00:23:00 -04:00
tcp_recovery.c tcp: do not assume TCP code is non preemptible 2016-05-02 17:02:25 -04:00
tcp_scalable.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_timer.c tcp: Change txhash on every SYN and RTO retransmit 2016-09-28 07:52:34 -04:00
tcp_vegas.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_vegas.h tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_veno.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_westwood.c tcp: replace cnt & rtt with struct in pkts_acked() 2016-05-11 14:43:19 -04:00
tcp_yeah.c tcp: cwnd does not increase in TCP YeAH 2016-09-08 17:16:12 -07:00
tunnel4.c tunnels: correct conditional build of MPLS and IPv6 2016-07-11 13:27:06 -07:00
udp.c udplite: call proper backlog handlers 2016-11-24 15:32:14 -05:00
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
udplite.c udplite: call proper backlog handlers 2016-11-24 15:32:14 -05:00
xfrm4_input.c netfilter: Pass net into okfn 2015-09-17 17:18:37 -07:00
xfrm4_mode_beet.c
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c ipv4: hash net ptr into fragmentation bucket selection 2015-03-25 14:07:04 -04:00
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 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-09-12 15:52:44 -07:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c