From 99b4dd9f2423130875ac486fe587cd103c64f753 Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Fri, 29 Jan 2016 15:11:50 -0800 Subject: [PATCH] tcp: avoid cwnd undo after receiving ECN RFC 4015 section 3.4 says the TCP sender MUST refrain from reversing the congestion control state when the ACK signals congestion through the ECN-Echo flag. Currently we may not always do that when prior_ssthresh is reset upon receiving ACKs with ECE marks. This patch fixes that. Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index d2ad4337b63d..1c2a73406261 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2366,8 +2366,6 @@ static void tcp_undo_cwnd_reduction(struct sock *sk, bool unmark_loss) tp->snd_ssthresh = tp->prior_ssthresh; tcp_ecn_withdraw_cwr(tp); } - } else { - tp->snd_cwnd = max(tp->snd_cwnd, tp->snd_ssthresh); } tp->snd_cwnd_stamp = tcp_time_stamp; tp->undo_marker = 0;