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authorEric Dumazet <edumazet@google.com>2019-10-01 01:44:44 +0300
committerDavid S. Miller <davem@davemloft.net>2019-10-02 04:40:49 +0300
commit3256a2d6ab1f71f9a1bd2d7f6f18eb8108c48d17 (patch)
treed2a73ff8ac5783d93545bb2bd497067c6243a1fa /net
parent0d9138ffac24cf8b75366ede3a68c951e6dcc575 (diff)
downloadlinux-3256a2d6ab1f71f9a1bd2d7f6f18eb8108c48d17.tar.xz
tcp: adjust rto_base in retransmits_timed_out()
The cited commit exposed an old retransmits_timed_out() bug which assumed it could call tcp_model_timeout() with TCP_RTO_MIN as rto_base for all states. But flows in SYN_SENT or SYN_RECV state uses a different RTO base (1 sec instead of 200 ms, unless BPF choses another value) This caused a reduction of SYN retransmits from 6 to 4 with the default /proc/sys/net/ipv4/tcp_syn_retries value. Fixes: a41e8a88b06e ("tcp: better handle TCP_USER_TIMEOUT in SYN_SENT state") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Marek Majkowski <marek@cloudflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_timer.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
index 40de2d2364a1..05be564414e9 100644
--- a/net/ipv4/tcp_timer.c
+++ b/net/ipv4/tcp_timer.c
@@ -198,8 +198,13 @@ static bool retransmits_timed_out(struct sock *sk,
return false;
start_ts = tcp_sk(sk)->retrans_stamp;
- if (likely(timeout == 0))
- timeout = tcp_model_timeout(sk, boundary, TCP_RTO_MIN);
+ if (likely(timeout == 0)) {
+ unsigned int rto_base = TCP_RTO_MIN;
+
+ if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
+ rto_base = tcp_timeout_init(sk);
+ timeout = tcp_model_timeout(sk, boundary, rto_base);
+ }
return (s32)(tcp_time_stamp(tcp_sk(sk)) - start_ts - timeout) >= 0;
}