From: Yuchung Cheng <ycheng@google.com>
To: davem@davemloft.net, ncardwell@google.com, edumazet@google.com
Cc: netdev@vger.kernel.org, Yuchung Cheng <ycheng@google.com>
Subject: [PATCH net] tcp: only take RTT from timestamps if new data is acked
Date: Thu, 24 Oct 2013 08:55:25 -0700 [thread overview]
Message-ID: <1382630125-21416-1-git-send-email-ycheng@google.com> (raw)
Patch ed08495c3 "tcp: use RTT from SACK for RTO" has a bug that
it does not check if the ACK acknowledge new data before taking
the RTT sample from TCP timestamps. This patch adds the check
back as required by the RFC.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
---
net/ipv4/tcp_input.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 305cd05..6ffe41a 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2856,7 +2856,8 @@ static inline bool tcp_ack_update_rtt(struct sock *sk, const int flag,
* left edge of the send window.
* See draft-ietf-tcplw-high-performance-00, section 3.3.
*/
- if (seq_rtt < 0 && tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
+ if (seq_rtt < 0 && tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
+ flag & FLAG_ACKED)
seq_rtt = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
if (seq_rtt < 0)
--
1.8.4.1
next reply other threads:[~2013-10-24 15:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-24 15:55 Yuchung Cheng [this message]
2013-10-24 17:02 ` [PATCH net] tcp: only take RTT from timestamps if new data is acked Neal Cardwell
2013-10-24 19:55 ` Eric Dumazet
2013-10-27 20:51 ` David Miller
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