From: Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH] Fix NAT TCP sequence adjustment
Date: Wed, 27 Apr 2005 10:44:00 +1000
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Cc: Harald Welte <laforge@netfilter.org>, netfilter-devel@lists.netfilter.org
To: Patrick McHardy <kaber@trash.net>
In-Reply-To: <4250FA72.3020502@trash.net>
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On Mon, 2005-04-04 at 10:27 +0200, Patrick McHardy wrote:
> Phil Oester wrote:
> > If the retransmitted packet were the same packet as the last one which was
> > mangled, the seq will be adjusted by offset_before, which at this point is
> > the same adjustment as the first packet received via offset_after. So,
> > seq == correction_pos for the retransmitted packet, and this is fairly trivial
> > to handle.  This is the only case where I can see before() triggering a false
> > positive.
> 
> What you are trying to do is to reconstruct the original sequence
> number, so lets consider the possible cases:

Please enhance nfsim-testsuite with these.  I dislike adding new hooks,
but to be honest I haven't had time to follow this conversation.  At
least a testcase will allow us to vet other solutions, and prevent us
from breaking this again.

Rusty.
-- 
A bad analogy is like a leaky screwdriver -- Richard Braakman