Re: [dpdk-dev] [PATCH v2] net: prepare the outer ipv4 hdr for checksum

From: Thomas Monjalon <thomas@monjalon.net>
To: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
Cc: Olivier Matz <olivier.matz@6wind.com>,
	dev@dpdk.org, ray.kinsella@intel.com, stable@dpdk.org,
	Tomasz Kulasek <tomaszx.kulasek@intel.com>,
	Konstantin Ananyev <konstantin.ananyev@intel.com>
Subject: Re: [dpdk-dev] [PATCH v2] net: prepare the outer ipv4 hdr for checksum
Date: Thu, 22 Jul 2021 21:53:31 +0200	[thread overview]
Message-ID: <4459484.c67x3OAJy8@thomas> (raw)
In-Reply-To: <CAKkt9++9mJoUOsmVTfZwP-fS651RMyHvDdCHSJgE8om0pB+wzw@mail.gmail.com>

07/07/2021 11:14, Mohsin Kazmi:
> On Wed, Jun 30, 2021 at 3:09 PM Olivier Matz <olivier.matz@6wind.com> wrote:
> > > +     if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
> > >               inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
> > > +             /*
> > > +              * prepare outer ipv4 header checksum by setting it to 0,
> > > +              * in order to be computed by hardware NICs.
> > > +              */
> > > +             if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
> > > +                     ipv4_hdr = rte_pktmbuf_mtod_offset(m,
> > > +                                     struct rte_ipv4_hdr *,
> > m->outer_l2_len);
> > > +                     ipv4_hdr->hdr_checksum = 0;
> > > +             }
> > > +     }
> >
> > What about outer L4 checksum? Does it requires the same than inner?
> >
> I am using XL710 for my testing with i40e dpdk driver. AFAIK, It doesn't
> support outer l4 checksum. I am not sure if other Intel NICs support it.

This function is used by a lot of drivers.
Try git grep rte_net_intel_cksum_prepare

I think we need more reviews on the v3.
Given it is far from being a new bug, I suggest to wait the next release
in order to have more feedbacks.