diff options
| author | Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> | 2007-08-30 06:21:05 +0200 |
|---|---|---|
| committer | Adrian Bunk <bunk@stusta.de> | 2007-09-24 23:02:47 +0200 |
| commit | 3198d0f16dec0c87071cf26f3f11af9c8f0a009b (patch) | |
| tree | 4fe6063703d512c44d18e8700d55c6cb5a7ffe0c | |
| parent | 725ad2a8f1358bff885414f5e91d253c99921ddc (diff) | |
TCP: Fix TCP handling of SACK in bidirectional flows
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 <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
| -rw-r--r-- | net/ipv4/tcp_input.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 412e3d214d7..cdeca2d5c11 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -1909,7 +1909,10 @@ 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. */ |