diff options
authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2007-02-21 23:06:52 -0800
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-25 22:23:09 -0700
commit52c63f1e86ebb18ef4b710b5b647e552a041e5ca (patch)
parent[TCP] FRTO: Response should reset also snd_cwnd_cnt (diff)
[TCP]: Don't enter to fast recovery while using FRTO
Because TCP is not in Loss state during FRTO recovery, fast recovery could be triggered by accident. Non-SACK FRTO is more robust than not yet included SACK-enhanced version (that can receiver high number of duplicate ACKs with SACK blocks during FRTO), at least with unidirectional transfers, but under extraordinary patterns fast recovery can be incorrectly triggered, e.g., Data loss+ACK losses => cumulative ACK with enough SACK blocks to meet sacked_out >= dupthresh condition). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
1 files changed, 4 insertions, 0 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 924b2e6d7d15..7213740477ee 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1547,6 +1547,10 @@ static int tcp_time_to_recover(struct sock *sk, struct tcp_sock *tp)
__u32 packets_out;
+ /* Do not perform any recovery during FRTO algorithm */
+ if (tp->frto_counter)
+ return 0;
/* Trick#1: The loss is proven. */
if (tp->lost_out)
return 1;