diff options
| author | Yuchung Cheng <ycheng@google.com> | 2017-08-01 13:22:32 -0700 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2017-11-02 07:16:23 +0100 |
| commit | 37cb36243061666f8bd44fdc51229ca6896effa3 (patch) | |
| tree | ddd3a709c194abe9e696cfd2118a904e2e6157d0 | |
| parent | 6f85a8873040becd7d779ad5f510f1b73d04f59b (diff) | |
tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states
commit ed254971edea92c3ac5c67c6a05247a92aa6075e upstream.
If the sender switches the congestion control during ECN-triggered
cwnd-reduction state (CA_CWR), upon exiting recovery cwnd is set to
the ssthresh value calculated by the previous congestion control. If
the previous congestion control is BBR that always keep ssthresh
to TCP_INIFINITE_SSTHRESH, cwnd ends up being infinite. The safe
step is to avoid assigning invalid ssthresh value when recovery ends.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
| -rw-r--r-- | net/ipv4/tcp_input.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 70f217cb3a1b..828835cb0708 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2554,8 +2554,8 @@ static inline void tcp_end_cwnd_reduction(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); /* Reset cwnd to ssthresh in CWR or Recovery (unless it's undone) */ - if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || - (tp->undo_marker && tp->snd_ssthresh < TCP_INFINITE_SSTHRESH)) { + if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH && + (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || tp->undo_marker)) { tp->snd_cwnd = tp->snd_ssthresh; tp->snd_cwnd_stamp = tcp_time_stamp; } |