netdev - Re: [PATCH 01/18] ipv4: fix path MTU discovery with connection tracking

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Date:	Mon, 20 Aug 2012 09:41:24 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Patrick McHardy <kaber@...sh.net>
Cc:	netfilter-devel@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH 01/18] ipv4: fix path MTU discovery with connection
 tracking

On Mon, 2012-08-20 at 05:39 +0200, Patrick McHardy wrote:
> IPv4 conntrack defragments incoming packet at the PRE_ROUTING hook and
> (in case of forwarded packets) refragments them at POST_ROUTING
> independant of the IP_DF flag. Refragmentation uses the dst_mtu() of
> the local route without caring about the original fragment sizes,
> thereby breaking PMTUD.
> 
> This patch fixes this by keeping track of the largest received fragment
> with IP_DF set and generates an ICMP fragmentation required error during
> refragmentation if that size exceeds the MTU.
> 
> Signed-off-by: Patrick McHardy <kaber@...sh.net>
> ---

Acked-by: Eric Dumazet <edumazet@...gle.com>


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