[CRIU] Re: [PATCH] tcp: restore rcv_wscale in a repair mode (v2)

Cyrill Gorcunov gorcunov at openvz.org
Wed Sep 19 07:03:48 EDT 2012


On Wed, Sep 19, 2012 at 03:00:23PM +0400, Pavel Emelyanov wrote:
> On 09/18/2012 12:12 PM, Andrew Vagin wrote:
> > rcv_wscale is a symetric parameter with snd_wscale.
> > 
> > Both this parameters are set on a connection handshake.
> > 
> > Without this value a remote window size can not be interpreted correctly,
> > because a value from a packet should be shifted on rcv_wscale.
> > 
> > And one more thing is that wscale_ok should be set too.
> > 
> > This patch doesn't break a backward compatibility.
> > If someone uses it in a old scheme, a rcv window
> > will be restored with the same bug (rcv_wscale = 0).
> > 
> > v2: Save backward compatibility on big-endian system. Before
> >     the first two bytes were snd_wscale and the second two bytes were
> >     rcv_wscale. Now snd_wscale is opt_val & 0xFFFF and rcv_wscale >> 16.
> >     This approach is independent on byte ordering.
> > 
> > CC: Pavel Emelyanov <xemul at parallels.com>
> > Signed-off-by: Andrew Vagin <avagin at openvz.org>
> 
> Cyrill, plz, push this patch to kernel repo.

Sure. Thanks.


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