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| author |   Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> | 2007-07-30 19:51:12 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@sunset.davemloft.net> | 2007-07-31 02:28:31 -0700 |
| commit | b8ed601cefe7a4014b93560bd846caf44f25b1c1 (patch) | |
| tree | 37df7bdfa7cb88195502e36440a21ce3897c9e40 /net/ipv4 | |
| parent | [TCP]: Fix ratehalving with bidirectional flows (diff) | |
| download | linux-dev-b8ed601cefe7a4014b93560bd846caf44f25b1c1.tar.xz linux-dev-b8ed601cefe7a4014b93560bd846caf44f25b1c1.zip | |
[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 <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
| -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 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. */ |