From: Ilpo Järvinen Date: Tue, 31 Jul 2007 02:51:12 +0000 (-0700) Subject: [TCP]: Bidir flow must not disregard SACK blocks for lost marking X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b8ed601cefe7a4014b93560bd846caf44f25b1c1;p=linux-beck.git [TCP]: Bidir flow must not disregard SACK blocks for lost marking It's possible that new SACK blocks that should trigger new LOST markings arrive with new data (which previously made is_dupack false). In addition, I think this fixes a case where we get a cumulative ACK with enough SACK blocks to trigger the fast recovery (is_dupack would be false there too). I'm not completely pleased with this solution because readability of the code is somewhat questionable as 'is_dupack' in SACK case is no longer about dupacks only but would mean something like 'lost_marker_work_todo' too... But because of Eifel stuff done in CA_Recovery, the FLAG_DATA_SACKED check cannot be placed to the if statement which seems attractive solution. Nevertheless, I didn't like adding another variable just for that either... :-) Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 41163ddc312c..378ca8a086a3 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2112,7 +2112,10 @@ tcp_fastretrans_alert(struct sock *sk, u32 prior_snd_una, { struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); - int is_dupack = (tp->snd_una == prior_snd_una && !(flag&FLAG_NOT_DUP)); + int is_dupack = (tp->snd_una == prior_snd_una && + (!(flag&FLAG_NOT_DUP) || + ((flag&FLAG_DATA_SACKED) && + (tp->fackets_out > tp->reordering)))); /* Some technical things: * 1. Reno does not count dupacks (sacked_out) automatically. */