tcp: better handle TCP_USER_TIMEOUT in SYN_SENT state
Yuchung Cheng and Marek Majkowski independently reported a weird behavior of TCP_USER_TIMEOUT option when used at connect() time. When the TCP_USER_TIMEOUT is reached, tcp_write_timeout() believes the flow should live, and the following condition in tcp_clamp_rto_to_user_timeout() programs one jiffie timers : remaining = icsk->icsk_user_timeout - elapsed; if (remaining <= 0) return 1; /* user timeout has passed; fire ASAP */ This silly situation ends when the max syn rtx count is reached. This patch makes sure we honor both TCP_SYNCNT and TCP_USER_TIMEOUT, avoiding these spurious SYN packets. Fixes: b701a99e ("tcp: Add tcp_clamp_rto_to_user_timeout() helper to improve accuracy") Signed-off-by:Eric Dumazet <edumazet@google.com> Reported-by:
Yuchung Cheng <ycheng@google.com> Reported-by:
Marek Majkowski <marek@cloudflare.com> Cc: Jon Maxwell <jmaxwell37@gmail.com> Link: https://marc.info/?l=linux-netdev&m=156940118307949&w=2 Acked-by:
Jon Maxwell <jmaxwell37@gmail.com> Tested-by:
Marek Majkowski <marek@cloudflare.com> Signed-off-by:
Marek Majkowski <marek@cloudflare.com> Acked-by:
Yuchung Cheng <ycheng@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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