From: David Miller <davem@davemloft.net>
To: herbert@gondor.apana.org.au
Cc: shemminger@linux-foundation.org, netdev@vger.kernel.org
Subject: Re: [NET]: Allow forwarding of ip_summed except CHECKSUM_COMPLETE
Date: Mon, 26 Mar 2007 23:23:05 -0700 (PDT) [thread overview]
Message-ID: <20070326.232305.85395483.davem@davemloft.net> (raw)
In-Reply-To: <20070327053821.GA23596@gondor.apana.org.au>
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Tue, 27 Mar 2007 15:38:21 +1000
> [NET]: Allow forwarding of ip_summed except CHECKSUM_COMPLETE
>
> Right now Xen has a horrible hack that lets it forward packets with
> partial checksums. One of the reasons that CHECKSUM_PARTIAL and
> CHECKSUM_COMPLETE were added is so that we can get rid of this hack
> (where it creates two extra bits in the skbuff to essentially mirror
> ip_summed without being destroyed by the forwarding code).
>
> I had forgotten that I've already gone through all the deivce drivers
> last time around to make sure that they're looking at ip_summed ==
> CHECKSUM_PARTIAL rather than ip_summed != 0 on transmit. In any case,
> I've now done that again so it should definitely be safe.
>
> Unfortunately nobody has yet added any code to update CHECKSUM_COMPLETE
> values on forward so we I'm setting that to CHECKSUM_NONE. This should
> be safe to remove for bridging but I'd like to check that code path
> first.
>
> So here is the patch that lets us get rid of the hack by preserving
> ip_summed (mostly) on forwarded packets.
>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Applied to net-2.6.22, thanks Herbert.
next prev parent reply other threads:[~2007-03-27 6:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-27 5:38 [NET]: Allow forwarding of ip_summed except CHECKSUM_COMPLETE Herbert Xu
2007-03-27 6:23 ` David Miller [this message]
2007-03-27 20:51 ` Patrick McHardy
2007-03-27 21:20 ` Herbert Xu
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