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authorYuchung Cheng <ycheng@google.com>2015-05-18 19:31:45 (GMT)
committerDavid S. Miller <davem@davemloft.net>2015-05-19 20:36:57 (GMT)
commitb7b0ed910cd8450db6d98cd4361c644bb1c88412 (patch)
tree906a1d4684054523fb8606b9f6f193f28319e2a3 /net
parentda34ac7626b571d262f92b93f11eb32dd58d9c4e (diff)
downloadlinux-b7b0ed910cd8450db6d98cd4361c644bb1c88412.tar.xz
tcp: don't over-send F-RTO probes
After sending the new data packets to probe (step 2), F-RTO may incorrectly send more probes if the next ACK advances SND_UNA and does not sack new packet. However F-RTO RFC 5682 probes at most once. This bug may cause sender to always send new data instead of repairing holes, inducing longer HoL blocking on the receiver for the application. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_input.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9faf775..243d674 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2710,9 +2710,9 @@ static void tcp_process_loss(struct sock *sk, int flag, bool is_dupack)
tcp_try_undo_loss(sk, true))
return;
- if (after(tp->snd_nxt, tp->high_seq) &&
- (flag & FLAG_DATA_SACKED || is_dupack)) {
- tp->frto = 0; /* Loss was real: 2nd part of step 3.a */
+ if (after(tp->snd_nxt, tp->high_seq)) {
+ if (flag & FLAG_DATA_SACKED || is_dupack)
+ tp->frto = 0; /* Step 3.a. loss was real */
} else if (flag & FLAG_SND_UNA_ADVANCED && !recovered) {
tp->high_seq = tp->snd_nxt;
__tcp_push_pending_frames(sk, tcp_current_mss(sk),