On Thu, Oct 13, 2016 at 04:52:25PM +0200, Olivier MATZ wrote:
> >In the "else" clause, the ip header is still in the mbuf, right?
> >Why do you have to access it the way like:
> >
> > ip_version = *rte_pktmbuf_mtod_offset(m, uint8_t *,
> > m->l2_len) >> 4;
> >
> >Why can't you just use
> >
> > iph = rte_pktmbuf_mtod_offset(m, struct ipv4_hdr *, m->l2_len);
> > iph->version_ihl ....;
>
> AFAIK, there is no requirement that each network header has to be contiguous
> in a mbuf segment.
>
> Of course, a split in the middle of a network header probably never
> happens... but we never knows, as it is not forbidden. I think the code
> should be robust enough to avoid accesses to wrong addresses.
One more question is do you have any case to trigger the "else" clause?
--yliu
