Re: [PATCH] netfilter: add CHECKSUM target

From: Herbert Xu
Date: Fri Jul 09 2010 - 03:18:58 EST


On Fri, Jul 09, 2010 at 01:29:13AM +0300, Michael S. Tsirkin wrote:
> This adds a `CHECKSUM' target, which can be used in the iptables mangle
> table.
>
> You can use this target to compute and fill in the checksum in
> an IP packet that lacks a checksum. This is particularly useful,
> if you need to work around old applications such as dhcp clients,
> that do not work well with checksum offloads, but don't want to
> disable checksum offload in your device.
>
> The problem happens in the field with virtualized applications.
> For reference, see Red Hat bz 605555, as well as
> http://www.spinics.net/lists/kvm/msg37660.html
>
> Typical expected use (helps old dhclient binary running in a VM):
> iptables -A POSTROUTING -t mangle -p udp --dport 68 -j CHECKSUM
> --checksum-fill
>
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>

I'd think that this target would be protocol-agnostic, no?

Cheers,
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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