Re: [dpdk-dev] [RFC] ethdev: add fragment attribute to IPv6 item

[Dekel Peled <dekelp@mellanox.com>]

Thanks, PSB.

> -----Original Message-----
> From: Stephen Hemminger <stephen@networkplumber.org>
> Sent: Monday, June 1, 2020 8:39 AM
> To: Dekel Peled <dekelp@mellanox.com>
> Cc: ferruh.yigit@intel.com; arybchenko@solarflare.com; Ori Kam
> <orika@mellanox.com>; john.mcnamara@intel.com;
> marko.kovacevic@intel.com; Asaf Penso <asafp@mellanox.com>; Matan
> Azrad <matan@mellanox.com>; Eli Britstein <elibr@mellanox.com>;
> dev@dpdk.org
> Subject: Re: [dpdk-dev] [RFC] ethdev: add fragment attribute to IPv6 item
> 
> On Sun, 31 May 2020 17:43:29 +0300
> Dekel Peled <dekelp@mellanox.com> wrote:
> 
> > Using the current implementation of DPDK, an application cannot match
> > on fragmented/non-fragmented IPv6 packets in a simple way.
> >
> > In current implementation:
> > IPv6 header doesn't contain information regarding the packet
> > fragmentation.
> > Fragmented IPv6 packets contain a dedicated extension header, as
> > detailed in RFC [1], which is not yet supported in rte_flow.
> > Non-fragmented packets don't contain the fragment extension header.
> > For an application to match on non-fragmented IPv6 packets, the
> > current implementation doesn't provide a suitable solution.
> > Matching on the Next Header field is not sufficient, since additional
> > extension headers might be present in the same packet.
> > To match on fragmented IPv6 packets, the same difficulty exists.
> >
> > Proposed update:
> > An additional value will be added to IPv6 header struct.
> > This value will contain the fragmentation attribute of the packet,
> > providing simple means for identification of fragmented and
> > non-fragmented packets.
> >
> > This update changes ABI, and is proposed for the 20.11 LTS version.
> >
> > [1]
> >
> https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmails
> > .dpdk.org%2Farchives%2Fdev%2F2020-
> March%2F160255.html&amp;data=02%7C01
> >
> %7Cdekelp%40mellanox.com%7C9ee87004dc3943b945c908d805ee0bcc%7Ca
> 652971c
> >
> 7d2e4d9ba6a4d149256f461b%7C0%7C0%7C637265867256841029&amp;sdata
> =rf1zYz
> >
> fNLGdqayXLHffO%2FrM%2FeX5op6KO91RDKq%2BYk3Q%3D&amp;reserved
> =0
> >
> > Signed-off-by: Dekel Peled <dekelp@mellanox.com>
> > ---
> >  lib/librte_ethdev/rte_flow.h | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/lib/librte_ethdev/rte_flow.h
> > b/lib/librte_ethdev/rte_flow.h index b0e4199..3bc8ce1 100644
> > --- a/lib/librte_ethdev/rte_flow.h
> > +++ b/lib/librte_ethdev/rte_flow.h
> > @@ -787,6 +787,8 @@ struct rte_flow_item_ipv4 {
> >   */
> >  struct rte_flow_item_ipv6 {
> >  	struct rte_ipv6_hdr hdr; /**< IPv6 header definition. */
> > +	uint32_t is_frag:1; /**< Is IPv6 packet fragmented/non-fragmented.
> */
> > +	uint32_t reserved:31; /**< Reserved, must be zero. */
> >  };
> 
> You can't do this in the 20.08 release it would be an ABI breakage.
Please see above, I noted in the commit log that this is proposed for 20.11.