diff options
author | Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> | 2007-07-30 22:51:12 -0400 |
---|---|---|
committer | David S. Miller <davem@sunset.davemloft.net> | 2007-07-31 05:28:31 -0400 |
commit | b8ed601cefe7a4014b93560bd846caf44f25b1c1 (patch) | |
tree | 37df7bdfa7cb88195502e36440a21ce3897c9e40 /net/ipv4/tcp_input.c | |
parent | 1e757f9996114f713a79d3fbcd08739efcfc5c34 (diff) |
[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/tcp_input.c')
-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, | |||
2112 | { | 2112 | { |
2113 | struct inet_connection_sock *icsk = inet_csk(sk); | 2113 | struct inet_connection_sock *icsk = inet_csk(sk); |
2114 | struct tcp_sock *tp = tcp_sk(sk); | 2114 | struct tcp_sock *tp = tcp_sk(sk); |
2115 | int is_dupack = (tp->snd_una == prior_snd_una && !(flag&FLAG_NOT_DUP)); | 2115 | int is_dupack = (tp->snd_una == prior_snd_una && |
2116 | (!(flag&FLAG_NOT_DUP) || | ||
2117 | ((flag&FLAG_DATA_SACKED) && | ||
2118 | (tp->fackets_out > tp->reordering)))); | ||
2116 | 2119 | ||
2117 | /* Some technical things: | 2120 | /* Some technical things: |
2118 | * 1. Reno does not count dupacks (sacked_out) automatically. */ | 2121 | * 1. Reno does not count dupacks (sacked_out) automatically. */ |