net/mlx5e: Support inner header rewrite with goto action

The hardware supports header rewrite of outer headers only.
To perform header rewrite on inner headers, we must first
decapsulate the packet.

Currently, the hardware decap action is explicitly set by the tc
tunnel_key unset action. However, with goto action the user won't
use the tunnel_key unset action. In addition, header rewrites actions
will not apply to the inner header as done by the software model.

To support this, we will map each tunnel matches seen on a tc rule to
a unique tunnel id, implicity add a decap action on tc chain 0 flows,
and mark the packets with this unique tunnel id. Tunnel matches on
the decapsulated tunnel on later chains will match on this unique id
instead of the actual packet.

We will also use this mapping to restore the tunnel info metadata
on miss.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en_rep.h

@@ -81,6 +81,11 @@ struct mlx5_rep_uplink_priv {
 	struct mutex                unready_flows_lock;
 	struct list_head            unready_flows;
 	struct work_struct          reoffload_flows_work;
+
+	/* maps tun_info to a unique id*/
+	struct mapping_ctx *tunnel_mapping;
+	/* maps tun_enc_opts to a unique id*/
+	struct mapping_ctx *tunnel_enc_opts_mapping;
 };
 
 struct mlx5e_rep_priv {