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From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Olivier Matz <olivier.matz@6wind.com>
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On Thu, Oct 13, 2016 at 05:45:21PM +0200, Olivier Matz wrote:
> >> If you have a packet split like this:
> >> 
> >> mbuf segment 1                     mbuf segment 2
> >> ----------------------------       ------------------------------
> >> | Ethernet header |  IP hea|       |der | TCP header | data
> >> ----------------------------       ------------------------------
> >>                    ^
> >>                    iph
> >
> >Thanks, that's clear. How could you be able to access the tcp header
> >from the first mbuf then? I mean, how is the following code supposed
> >to work?
> >
> >    prev_cksum.u8[0] = *rte_pktmbuf_mtod_offset(m, uint8_t *,
> >			m->l2_len + m->l3_len + 16);
> >
> 
> Oh I see... Sorry there was a confusion on my side with another (internal) macro that browses the segments if the offset ils not in the first one.
> 
> If you agree, let's add the code without the else part, I'll fix it for the rc2.

Good. That's okay to me.

	--yliu