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| author | Neal Cardwell <ncardwell@google.com> | 2015-04-01 20:26:46 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-04-02 16:35:58 -0400 |
| commit | 666b805150efd62f05810ff0db08f44a2370c937 (patch) | |
| tree | 265d4aba6edfc0b63a07ba13f2c05eafe4e2ad4f | |
| parent | 0c36820e2ab7d943ab1188230fdf2149826d33c0 (diff) | |
| download | linux-666b805150efd62f05810ff0db08f44a2370c937.tar.gz linux-666b805150efd62f05810ff0db08f44a2370c937.tar.bz2 linux-666b805150efd62f05810ff0db08f44a2370c937.zip | |
tcp: fix FRTO undo on cumulative ACK of SACKed range
On processing cumulative ACKs, the FRTO code was not checking the
SACKed bit, meaning that there could be a spurious FRTO undo on a
cumulative ACK of a previously SACKed skb.
The FRTO code should only consider a cumulative ACK to indicate that
an original/unretransmitted skb is newly ACKed if the skb was not yet
SACKed.
The effect of the spurious FRTO undo would typically be to make the
connection think that all previously-sent packets were in flight when
they really weren't, leading to a stall and an RTO.
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Fixes: e33099f96d99c ("tcp: implement RFC5682 F-RTO")
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/tcp_input.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index fb4cf8b8e121..f501ac048366 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3105,10 +3105,11 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, if (!first_ackt.v64) first_ackt = last_ackt; - if (!(sacked & TCPCB_SACKED_ACKED)) + if (!(sacked & TCPCB_SACKED_ACKED)) { reord = min(pkts_acked, reord); - if (!after(scb->end_seq, tp->high_seq)) - flag |= FLAG_ORIG_SACK_ACKED; + if (!after(scb->end_seq, tp->high_seq)) + flag |= FLAG_ORIG_SACK_ACKED; + } } if (sacked & TCPCB_SACKED_ACKED) |