From 2e117bb2abf3e5722d6984e358166c674a70250d Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Wed, 28 Nov 2018 16:06:45 -0800 Subject: [PATCH] tcp: fix SNMP TCP timeout under-estimation [ Upstream commit e1561fe2dd69dc5dddd69bd73aa65355bdfb048b ] Previously the SNMP TCPTIMEOUTS counter has inconsistent accounting: 1. It counts all SYN and SYN-ACK timeouts 2. It counts timeouts in other states except recurring timeouts and timeouts after fast recovery or disorder state. Such selective accounting makes analysis difficult and complicated. For example the monitoring system needs to collect many other SNMP counters to infer the total amount of timeout events. This patch makes TCPTIMEOUTS counter simply counts all the retransmit timeout (SYN or data or FIN). Signed-off-by: Yuchung Cheng Signed-off-by: Eric Dumazet Signed-off-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/tcp_timer.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 04e2c43a43a5..65f66bd585e6 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -464,11 +464,12 @@ void tcp_retransmit_timer(struct sock *sk) goto out_reset_timer; } + __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPTIMEOUTS); if (tcp_write_timeout(sk)) goto out; if (icsk->icsk_retransmits == 0) { - int mib_idx; + int mib_idx = 0; if (icsk->icsk_ca_state == TCP_CA_Recovery) { if (tcp_is_sack(tp)) @@ -483,10 +484,9 @@ void tcp_retransmit_timer(struct sock *sk) mib_idx = LINUX_MIB_TCPSACKFAILURES; else mib_idx = LINUX_MIB_TCPRENOFAILURES; - } else { - mib_idx = LINUX_MIB_TCPTIMEOUTS; } - __NET_INC_STATS(sock_net(sk), mib_idx); + if (mib_idx) + __NET_INC_STATS(sock_net(sk), mib_idx); } tcp_enter_loss(sk);