On Mon, Apr 22, 2013 at 7:19 PM, Simon Horman <ho...@verge.net.au> wrote:
> In the case where a non-MPLS GSO skb becomes an MPLS GSO skb, via
> Open vSwitch's push MPLS action it is desirable to provide segmentation
> in software. In this case the original protocol of the skb may have allowed
> its checksumming to be offloaded but this may no longer be supported now
> the skb is MPLS. Actually it seems to me that this is the likely case.
>
> In order to allow the checksum to be updated in this case loosen
> the rules for recalculating the checksum on in skb_segment().
>
> N.B.: I must confess that I am a little unsure of the details of
> the implementation of skb_checksum(). But I have observed that this
> is necessary as skb_checksum() hits the following:
>
> if (!hsize && i >= nfrags) {
> ...
> fskb = fskb->next;
> ...
> }
> ...
> if (fskb != skb_shinfo(skb)->frag_list)
> ...
>
> Signed-off-by: Simon Horman <ho...@verge.net.au>
I'm surprised at the need for changes here since neither vlans nor
tunneling protocols needed something similar. Do you know what is
special about MPLS that is triggering this?
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