From 9ead9a1d385ae2c52a6dcf2828d84ce66be04fc2 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Wed, 21 Feb 2007 22:56:19 -0800 Subject: [PATCH] [TCP] FRTO: Separated response from FRTO detection algorithm MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit FRTO spurious RTO detection algorithm (RFC4138) does not include response to a detected spurious RTO but can use different response algorithms. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index b21e232d5d33..c5be3d0465f5 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2467,6 +2467,15 @@ static int tcp_ack_update_window(struct sock *sk, struct tcp_sock *tp, return flag; } +/* A very conservative spurious RTO response algorithm: reduce cwnd and + * continue in congestion avoidance. + */ +static void tcp_conservative_spur_to_response(struct tcp_sock *tp) +{ + tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh); + tcp_moderate_cwnd(tp); +} + static void tcp_process_frto(struct sock *sk, u32 prior_snd_una) { struct tcp_sock *tp = tcp_sk(sk); @@ -2488,12 +2497,7 @@ static void tcp_process_frto(struct sock *sk, u32 prior_snd_una) */ tp->snd_cwnd = tcp_packets_in_flight(tp) + 2; } else { - /* Also the second ACK after RTO advances the window. - * The RTO was likely spurious. Reduce cwnd and continue - * in congestion avoidance - */ - tp->snd_cwnd = min(tp->snd_cwnd, tp->snd_ssthresh); - tcp_moderate_cwnd(tp); + tcp_conservative_spur_to_response(tp); } /* F-RTO affects on two new ACKs following RTO. -- 2.20.1