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From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>
Subject: [RFC] ECN and IP defragmentation
Date: Wed, 05 Jan 2011 01:13:51 +0100	[thread overview]
Message-ID: <1294186431.3420.19.camel@edumazet-laptop> (raw)

Hi David

It seems ip_fragment.c doesnt comply with RFC3168, section 5.3

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.




Should we fix this ?

(I tried to use ECN on UDP messages and noticed this problem)

Thanks



             reply	other threads:[~2011-01-05  0:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-05  0:13 Eric Dumazet [this message]
2011-01-05  2:53 ` [RFC] ECN and IP defragmentation David Miller
2011-01-05 13:59 ` [PATCH] ipv4: IP defragmentation must be ECN aware Eric Dumazet
2011-01-05 17:13   ` Stephen Hemminger
2011-01-05 17:41     ` Eric Dumazet
2011-01-05 17:48       ` Stephen Hemminger
2011-01-05 17:52         ` Eric Dumazet
2011-01-06 19:21           ` David Miller

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