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

[Andrew Vagin]

A bit more details in the commit message:

tcp: initialize rcv_tstamp for restored sockets

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.


On Tue, Aug 20, 2013 at 10:50:43AM +0400, Andrey Vagin wrote:
> From: Andrew Vagin <avagin at openvz.org>
> 
> u32 rcv_tstamp;     /* timestamp of last received ACK */
> 
> Its value used in tcp_retransmit_timer and if the last ack was received
> more then TCP_RTO_MAX ago, the socket will be closed.
> 
> This patch initializes rcv_tstamp to a timestamp, when a socket was
> restored.
> 
> Cc: Pavel Emelyanov <xemul at parallels.com>
> Reported-by: Cyrill Gorcunov <gorcunov at openvz.org>
> Signed-off-by: Andrey Vagin <avagin at 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
>