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Date: Thu, 02 Apr 2009 13:00:59 +0200
From: Paolo Pisati <p.pisati@oltrelinux.com>
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To: Luigi Rizzo <rizzo@iet.unipi.it>
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Cc: freebsd-ipfw@FreeBSD.org, Dmitriy Demidov <dima_bsd@inbox.lv>,
	Alex Dupre <ale@FreeBSD.org>
Subject: Re: keep-state rules inadequately handles big UDP packets
 or	fragmented IP packets?
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Luigi Rizzo wrote:
>
> Ok then we may have a plan:
>
> you could do is implement REASS as an action (not as a microinstruction),
> with the following behaviour:
>
> - if the packet is a complete one, the rule behaves as a "count"
>   (i.e. the firewall continues with the next rule);
>
> - if the packet is a fragment and can be reassembled, the rule
>   behaves as a "count" and the mbuf is replaced with the full packet;
>
> - if the packet is a fragment and cannot be reassembled, the
>   rule behaves as a "drop" (i.e. processing stops)
>   and the packet is swallowed by ipfw.
>
> This seems a useful behaviour, but it must be documented very
> clearly because it is not completely intuitive. Perhaps we should
> find a more descriptive name.
>   
committed yesterday in HEAD as "reass" action, and here is the 7.x 
patch: http://people.freebsd.org/~piso/ipfw-reass-7x.diff

-- 

bye,
P.