net/mlx5e: CT: Introduce connection tracking

Add support for offloading tc ct action and ct matches.
We translate the tc filter with CT action the following HW model:

+-------------------+      +--------------------+    +--------------+
+ pre_ct (tc chain) +----->+ CT (nat or no nat) +--->+ post_ct      +----->
+ original match    +  |   + tuple + zone match + |  + fte_id match +  |
+-------------------+  |   +--------------------+ |  +--------------+  |
                       v                          v                    v
                      set chain miss mapping  set mark             original
                      set fte_id              set label            filter
                      set zone                set established      actions
                      set tunnel_id           do nat (if needed)
                      do decap

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/Kconfig

@@ -78,6 +78,16 @@ config MLX5_ESWITCH
 	        Legacy SRIOV mode (L2 mac vlan steering based).
 	        Switchdev mode (eswitch offloads).
 
+config MLX5_TC_CT
+	bool "MLX5 TC connection tracking offload support"
+	depends on MLX5_CORE_EN && NET_SWITCHDEV && NF_FLOW_TABLE && NET_ACT_CT && NET_TC_SKB_EXT
+	default y
+	help
+	  Say Y here if you want to support offloading connection tracking rules
+	  via tc ct action.
+
+	  If unsure, set to Y
+
 config MLX5_CORE_EN_DCB
 	bool "Data Center Bridging (DCB) Support"
 	default y

drivers/net/ethernet/mellanox/mlx5/core/Makefile

@@ -37,6 +37,7 @@ mlx5_core-$(CONFIG_MLX5_ESWITCH)     += en_rep.o en_tc.o en/tc_tun.o lib/port_tu
 					lib/geneve.o en/mapping.o en/tc_tun_vxlan.o en/tc_tun_gre.o \
 					en/tc_tun_geneve.o diag/en_tc_tracepoint.o
 mlx5_core-$(CONFIG_PCI_HYPERV_INTERFACE) += en/hv_vhca_stats.o
+mlx5_core-$(CONFIG_MLX5_TC_CT)	     += en/tc_ct.o
 
 #
 # Core extra