[PATCH] tcp: initialize rcv_tstamp for restored sockets

[PATCH] tcp: initialize rcv_tstamp for restored sockets

[Andrey Vagin]

From: Andrew Vagin <avagin@openvz.org>

u32 rcv_tstamp;     /* timestamp of last received ACK */

Its value used in tcp_retransmit_timer, which closes socket
if the last ack was received more then TCP_RTO_MAX ago.

Currently rcv_tstamp is initialized to zero and if tcp_retransmit_timer
is called before receiving a first ack, the connection is closed.

This patch initializes rcv_tstamp to a timestamp, when a socket was
restored.

Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
---
 net/ipv4/tcp_output.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 92fde8d..e297299 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2814,6 +2814,8 @@ void tcp_connect_init(struct sock *sk)
 
 	if (likely(!tp->repair))
 		tp->rcv_nxt = 0;
+	else
+		tp->rcv_tstamp = tcp_time_stamp;
 	tp->rcv_wup = tp->rcv_nxt;
 	tp->copied_seq = tp->rcv_nxt;
 
-- 
1.8.3.1

Re: [PATCH] tcp: initialize rcv_tstamp for restored sockets

[David Miller]

From: Andrey Vagin <avagin@openvz.org>
Date: Tue, 27 Aug 2013 12:20:40 +0400

> From: Andrew Vagin <avagin@openvz.org>
> 
> u32 rcv_tstamp;     /* timestamp of last received ACK */
> 
> Its value used in tcp_retransmit_timer, which closes socket
> if the last ack was received more then TCP_RTO_MAX ago.
> 
> Currently rcv_tstamp is initialized to zero and if tcp_retransmit_timer
> is called before receiving a first ack, the connection is closed.
> 
> This patch initializes rcv_tstamp to a timestamp, when a socket was
> restored.
> 
> Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
> Signed-off-by: Andrey Vagin <avagin@openvz.org>

Applied and queued up for -stable.