net/mlx5e: Add flow groups for the packets decrypted by crypto offload

net/mlx5e: Add flow groups for the packets decrypted by crypto offload

When using IPsec crypto offload, the hardware decrypts the packet
payload but preserves the ESP header. This prevents the standard RSS
mechanism from accessing the inner L4 (TCP/UDP) headers. As a result,
the RSS hash is calculated only on the outer L3 IP headers, causing
all traffic for a given IPsec tunnel to be directed to a single queue,
leading to poor traffic distribution.

Newer firmware introduces the ability to match on l4_type_ext, which
exposes the L4 protocol type following an ESP header. This allows the
driver to create steering rules that can identify the inner protocols
of decrypted packets.

This commit leverages this new capability to improve traffic
distribution. It adds two new flow groups to steer decrypted packets
to dedicated TIRs that was configured to perform RSS on the inner L4
headers.

These groups are inserted after the standard L4 group and before the
group that handles undecrypted ESP packets added in this series. The
first new group matches decrypted packets based on the outer IP
version (or ethertype) and l4_type_ext. The second new group matches
decrypted tunneled packets based on the inner IP version and
l4_type_ext. Eight new traffic types are also defined to support this
functionality.

Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1758179963-649455-4-git-send-email-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>