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[TCP]: fix D-SACK cwnd handling

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In the current net-2.6 kernel, handling FLAG_DSACKING_ACK is broken.
The flag is cleared to 1 just after FLAG_DSACKING_ACK is set.

        if (found_dup_sack)
                flag |= FLAG_DSACKING_ACK;
	:
	flag = 1;

To fix it, this patch introduces a part of the tcp_sacktag_state patch:
	http://marc.info/?l=linux-netdev&m=119210560431519&w=2

Signed-off-by: Ryousei Takano <takano-ryousei@aist.go.jp>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ryousei Takano 2007-10-26 04:27:59 -07:00 committed by David S. Miller
parent 43cc7380ec
commit 94d3b1e586
1 changed files with 5 additions and 7 deletions
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12
net/ipv4/tcp_input.c
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@ -1248,6 +1248,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
int cached_fack_count;
int i;
int first_sack_index;
int force_one_sack;
if (!tp->sacked_out) {
if (WARN_ON(tp->fackets_out))
@ -1272,18 +1273,18 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
* if the only SACK change is the increase of the end_seq of
* the first block then only apply that SACK block
* and use retrans queue hinting otherwise slowpath */
flag = 1;
force_one_sack = 1;
for (i = 0; i < num_sacks; i++) {
__be32 start_seq = sp[i].start_seq;
__be32 end_seq = sp[i].end_seq;
if (i == 0) {
if (tp->recv_sack_cache[i].start_seq != start_seq)
flag = 0;
force_one_sack = 0;
} else {
if ((tp->recv_sack_cache[i].start_seq != start_seq) ||
(tp->recv_sack_cache[i].end_seq != end_seq))
flag = 0;
force_one_sack = 0;
}
tp->recv_sack_cache[i].start_seq = start_seq;
tp->recv_sack_cache[i].end_seq = end_seq;
@ -1295,7 +1296,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
}
first_sack_index = 0;
if (flag)
if (force_one_sack)
num_sacks = 1;
else {
int j;
@ -1321,9 +1322,6 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
}
}
/* clear flag as used for different purpose in following code */
flag = 0;
/* Use SACK fastpath hint if valid */
cached_skb = tp->fastpath_skb_hint;
cached_fack_count = tp->fastpath_cnt_hint;