From: tingwei liu
Date: Sun Jun 23 2013 - 21:43:12 EST

On Thu, Jun 20, 2013 at 8:51 PM, Jiri Slaby <jslaby@xxxxxxx> wrote:
> On 06/20/2013 02:28 PM, tingwei liu wrote:
>> Hi, dears:
>> On Suse 11 sp2 3.0.13 kernel. After a few days, Nginx reply
>> packets with src ip and dst ipã
>> Just like Is
>> there a bug?
> You should better report this via suse's standard channels (suse
> support/bugzilla). We cannot help you otherwise.
> thanks,
> --
> js
> suse labs

The problem has been fixed. It is a known bug has fixed by Eric Dumazet.

commit dfd25ffffc132c00070eed64200e8950da5d7e9d
Author: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Date: Sat Mar 10 09:20:21 2012 +0000

tcp: fix syncookie regression

commit ea4fc0d619 (ipv4: Don't use rt->rt_{src,dst} in ip_queue_xmit())
added a serious regression on synflood handling.

Simon Kirby discovered a successful connection was delayed by 20 seconds
before being responsive.

In my tests, I discovered that xmit frames were lost, and needed ~4
retransmits and a socket dst rebuild before being really sent.

In case of syncookie initiated connection, we use a different path to
initialize the socket dst, and inet->cork.fl.u.ip4 is left cleared.

As ip_queue_xmit() now depends on inet flow being setup, fix this by
copying the temp flowi4 we use in cookie_v4_check().

Reported-by: Simon Kirby <sim@xxxxxxxxxxxxx>
Bisected-by: Simon Kirby <sim@xxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Tested-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
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