net/mlx5e: Support RX xfrm state selector's UPSPEC for packet offload

net/mlx5e: Support RX xfrm state selector's UPSPEC for packet offload

Previously, the upper layer matches are added for the decryption rule
when xfrm selector's UPSPEC is specified in the command. However, it's
impossible as packets are not decrypted, and there is no way to do
match on the upper protocol (TCP/UDP) with specific source/destination
port. The result is that packets are not decrypted by hardware because
of this mismatch. Instead, they are forwarded to kernel, and
decryption is done by software.

To resolve this issue, this patch adds new table (sa_sel) after status
table and before policy table. When UPSPEC's proto is specified in
xfrm state's selector, a rule is added in status table to forward the
decrypted packets to sa_sel table, where the corresponding rule for
selector's UPSPEC is added, and packet's upper headers are checked
there. If matched, they will be forward to policy table to do policy
check. Otherwise, they are dropped immediately.

Besides, add a global count for this kind of packet drop.

Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20250220213959.504304-9-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>