netdev - Re: [PATCH -next, V3 0/2] net: force refragmentation for DF reassembed skbs

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Message-Id: <20150527.130401.726728313381454100.davem@davemloft.net>
Date:	Wed, 27 May 2015 13:04:01 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	fw@...len.de
Cc:	netdev@...r.kernel.org, hannes@...essinduktion.org
Subject: Re: [PATCH -next, V3 0/2] net: force refragmentation for DF
 reassembed skbs

From: Florian Westphal <fw@...len.de>
Date: Fri, 22 May 2015 16:32:49 +0200

> output path tests:
> 
>     if (skb->len > mtu) ip_fragment()
> 
> This breaks connectivity in one corner case:
>  If the skb was reassembled, but has the DF bit set and ..
>  .. its reassembled size is <= outdev mtu ..
>  .. we will forward a DF packet larger than what the sender
>     transmitted on wire.
> 
> If a router later in the path can't forward this packet, it will send an
> icmp error in response to an mtu that the original sender never exceeded.
> 
> This changes ipv4 defrag/output path to
> 
> a) force refragmentation for DF reassembled skbs and
> b) set DF bit on all fragments when refragmenting if it was set on original
> frags.
 ...

Series applied, thanks Florian.
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