On Sun, Aug 17, 2003 at 10:38:51PM -0700, David S. Miller wrote:
> On Mon, 18 Aug 2003 05:37:11 +0200
> Petr Vandrovec <vandrove@xxxxxxxxxx> wrote:
>
> > For me it would be best if dev_queue_xmit_nit could just leave
> > skb->h.raw alone,
>
> The AF_PACKET layer depends upon skb->h.raw being set a certain
> way. Have a look at the dev_add_pack() registered hooks that
> net/packet/af_packet.c uses.
Well, I do not see skb->h.raw used in any way in AF_PACKET hooks...
Probably I missed some deeply nested generic function which accesses
it...
> > Other choice is doing checksumming in dev_queue_xmit_nit itself,
> > before passing skb down to the registered packet handlers.
>
> This is not an option either. We're specifically not going to
> undo checksum offloading just because tcpdump or some other
> kind of tap is installed.
And what's left, then? I can happilly offload checksum to some
other place down in the chain, but for doing that I must know
where I should put checksum, and currently this information is
unavailable to the packet hook.
Best regards,
Petr Vandrovec
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