[TCP]: Two fixes to new sacktag code
1) Skip condition used to be wrong way around which made SACK
processing very broken, missed many blocks because of that.
2) Use highest_sack advancement only if some skbs are already
sacked because otherwise tcp_write_queue_next may move things
too far (occurs mainly with GSO). The other similar advancement
is not problem because highest_sack was previosly put to point
a sacked skb.
These problems were located because of problem report from Matt
Mathis <mathis@psc.edu>.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 97ea3ed..33d284e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1384,7 +1384,7 @@
if (skb == tcp_send_head(sk))
break;
- if (before(TCP_SKB_CB(skb)->end_seq, skip_to_seq))
+ if (!before(TCP_SKB_CB(skb)->end_seq, skip_to_seq))
break;
}
return skb;
@@ -1575,7 +1575,7 @@
continue;
}
- if (!before(start_seq, tcp_highest_sack_seq(tp))) {
+ if (tp->sacked_out && !before(start_seq, tcp_highest_sack_seq(tp))) {
skb = tcp_write_queue_next(sk, tp->highest_sack);
fack_count = tp->fackets_out;
}