[01/10] ethdev: add extensions attributes to IPv6 item

  Using the current implementation of DPDK, an application cannot match on
IPv6 packets, based on the existing extension headers, in a simple way.

Field 'Next Header' in IPv6 header indicates type of the first extension
header only. Following extension headers can't be identified by
inspecting the IPv6 header.
As a result, the existence or absence of specific extension headers
can't be used for packet matching.

For example, fragmented IPv6 packets contain a dedicated extension header
(which is implemented in a later patch of this series).
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.

This patch implements the update as detailed in RFC [1].
A set of additional values will be added to IPv6 header struct.
These values will indicate the existence of every defined extension
header type, providing simple means for identification of existing
extensions in the packet header.
Continuing the above example, fragmented packets can be identified using
the specific value indicating existence of fragment extension header.

[1] https://mails.dpdk.org/archives/dev/2020-August/177257.html

Signed-off-by: Dekel Peled <dekelp@nvidia.com>
---
 doc/guides/prog_guide/rte_flow.rst | 16 +++++++++++++---
 lib/librte_ethdev/rte_flow.h       | 25 +++++++++++++++++++++++--
 2 files changed, 36 insertions(+), 5 deletions(-)
  

> -----Original Message-----
> From: Dekel Peled <dekelp@nvidia.com>
> Sent: Wednesday, September 30, 2020 5:10 PM
> Subject: [PATCH 01/10] ethdev: add extensions attributes to IPv6 item
> 
> Using the current implementation of DPDK, an application cannot match on
> IPv6 packets, based on the existing extension headers, in a simple way.
> 
> Field 'Next Header' in IPv6 header indicates type of the first extension
> header only. Following extension headers can't be identified by
> inspecting the IPv6 header.
> As a result, the existence or absence of specific extension headers
> can't be used for packet matching.
> 
> For example, fragmented IPv6 packets contain a dedicated extension header
> (which is implemented in a later patch of this series).
> 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.
> 
> This patch implements the update as detailed in RFC [1].
> A set of additional values will be added to IPv6 header struct.
> These values will indicate the existence of every defined extension
> header type, providing simple means for identification of existing
> extensions in the packet header.
> Continuing the above example, fragmented packets can be identified using
> the specific value indicating existence of fragment extension header.
> 
> [1]
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmails.dp
> dk.org%2Farchives%2Fdev%2F2020-
> August%2F177257.html&amp;data=02%7C01%7Corika%40nvidia.com%7C5a12
> 16c396994e296ce308d8654aa25a%7C43083d15727340c1b7db39efd9ccc17a%7
> C0%7C1%7C637370718505729468&amp;sdata=ym5QBAFHOsuNfcKxhc%2Fj60B
> ojpD%2B5G1mvUuYAxKZP6k%3D&amp;reserved=0
> 
> Signed-off-by: Dekel Peled <dekelp@nvidia.com>
> ---
Acked-by: Ori Kam <orika@nvidia.com>
Thanks,
Ori