RE: [v2 1/4] lib: add optional fields in GRE header

["Sean Zhang (Networking SW)" <xiazhang@nvidia.com>]

Hi Ferruh,

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit@intel.com>
> Sent: Friday, February 11, 2022 5:38 PM
> To: Sean Zhang (Networking SW) <xiazhang@nvidia.com>; NBU-Contact-
> Thomas Monjalon (EXTERNAL) <thomas@monjalon.net>; Olivier Matz
> <olivier.matz@6wind.com>
> Cc: dev@dpdk.org; Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>;
> Ori Kam <orika@nvidia.com>
> Subject: Re: [v2 1/4] lib: add optional fields in GRE header
> 
> External email: Use caution opening links or attachments
> 
> 
> On 2/11/2022 1:45 AM, Sean Zhang wrote:
> > There are optional fields in GRE header(checksum/key/sequence), this
> > patch adds definition of structures of the optional fields.
> >
> > Signed-off-by: Sean Zhang <xiazhang@nvidia.com>
> > ---
> >   lib/net/rte_gre.h | 22 ++++++++++++++++++++++
> >   1 file changed, 22 insertions(+)
> >
> > diff --git a/lib/net/rte_gre.h b/lib/net/rte_gre.h index
> > 5897756..6c6aef6 100644
> > --- a/lib/net/rte_gre.h
> > +++ b/lib/net/rte_gre.h
> > @@ -48,6 +48,28 @@ struct rte_gre_hdr {
> >       uint16_t proto;  /**< Protocol Type */
> >   } __rte_packed;
> >
> > +/**
> > + * Optional field checksum in GRE header  */ struct
> > +rte_gre_hdr_opt_checksum_rsvd {
> > +     rte_be16_t checksum;
> > +     rte_be16_t reserved1;
> 
> Can you please explain why this reserved field is added, I guess it i not part of
> the GRE spec, but added for mlx driver?
> 

Yes, the reserverd1 field is part of GRE spec, and the field go together with checksum field, so I add the reserverd1 field here.

You can refer to section 2.6 of https://datatracker.ietf.org/doc/rfc2784/ 

> Since these struts will be public, we can't update them later easily, so we
> should be careful on them.
> 
> > +} __rte_packed;
> > +
> > +/**
> > + * Optional field key in GRE header
> > + */
> > +struct rte_gre_hdr_opt_key {
> > +     rte_be32_t key;
> > +} __rte_packed;
> > +
> > +/**
> > + * Optional field sequence in GRE header  */ struct
> > +rte_gre_hdr_opt_sequence {
> > +     rte_be32_t sequence;
> > +} __rte_packed;
> > +
> >   #ifdef __cplusplus
> >   }
> >   #endif