Re: [PATCH] ipv4: IP defragmentation must be ECN aware

[David Miller <davem@davemloft.net>]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 05 Jan 2011 18:52:55 +0100

> [PATCH v2] ipv4: IP defragmentation must be ECN aware
> 
> RFC3168 (The Addition of Explicit Congestion Notification to IP)
> states :
> 
> 5.3.  Fragmentation
> 
>    ECN-capable packets MAY have the DF (Don't Fragment) bit set.
>    Reassembly of a fragmented packet MUST NOT lose indications of
>    congestion.  In other words, if any fragment of an IP packet to be
>    reassembled has the CE codepoint set, then one of two actions MUST be
>    taken:
> 
>       * Set the CE codepoint on the reassembled packet.  However, this
>         MUST NOT occur if any of the other fragments contributing to
>         this reassembly carries the Not-ECT codepoint.
> 
>       * The packet is dropped, instead of being reassembled, for any
>         other reason.
> 
> This patch implements this requirement for IPv4, choosing the first
> action : 
> 
> If one fragment had NO-ECT codepoint
>         reassembled frame has NO-ECT
> ElIf one fragment had CE codepoint
>         reassembled frame has CE
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

Applied, thanks a lot Eric.