net/mlx5: Support GRE conntrack offload

Support GREv0 without NAT.
Signed-off-by: Toshiaki Makita <toshiaki.makita1@gmail.com>
Acked-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c

@@ -258,7 +258,8 @@ mlx5_tc_ct_rule_to_tuple(struct mlx5_ct_tuple *tuple, struct flow_rule *rule)
 			return -EOPNOTSUPP;
 		}
 	} else {
-		return -EOPNOTSUPP;
+		if (tuple->ip_proto != IPPROTO_GRE)
+			return -EOPNOTSUPP;
 	}
 
 	return 0;
@@ -807,7 +808,11 @@ mlx5_tc_ct_entry_add_rule(struct mlx5_tc_ct_priv *ct_priv,
 	attr->dest_chain = 0;
 	attr->dest_ft = mlx5e_tc_post_act_get_ft(ct_priv->post_act);
 	attr->ft = nat ? ct_priv->ct_nat : ct_priv->ct;
-	attr->outer_match_level = MLX5_MATCH_L4;
+	if (entry->tuple.ip_proto == IPPROTO_TCP ||
+	    entry->tuple.ip_proto == IPPROTO_UDP)
+		attr->outer_match_level = MLX5_MATCH_L4;
+	else
+		attr->outer_match_level = MLX5_MATCH_L3;
 	attr->counter = entry->counter->counter;
 	attr->flags |= MLX5_ATTR_FLAG_NO_IN_PORT;
 	if (ct_priv->ns_type == MLX5_FLOW_NAMESPACE_FDB)
@@ -1224,16 +1229,20 @@ mlx5_tc_ct_skb_to_tuple(struct sk_buff *skb, struct mlx5_ct_tuple *tuple,
 	struct flow_keys flow_keys;
 
 	skb_reset_network_header(skb);
-	skb_flow_dissect_flow_keys(skb, &flow_keys, 0);
+	skb_flow_dissect_flow_keys(skb, &flow_keys, FLOW_DISSECTOR_F_STOP_BEFORE_ENCAP);
 
 	tuple->zone = zone;
 
 	if (flow_keys.basic.ip_proto != IPPROTO_TCP &&
-	    flow_keys.basic.ip_proto != IPPROTO_UDP)
+	    flow_keys.basic.ip_proto != IPPROTO_UDP &&
+	    flow_keys.basic.ip_proto != IPPROTO_GRE)
 		return false;
 
-	tuple->port.src = flow_keys.ports.src;
-	tuple->port.dst = flow_keys.ports.dst;
+	if (flow_keys.basic.ip_proto == IPPROTO_TCP ||
+	    flow_keys.basic.ip_proto == IPPROTO_UDP) {
+		tuple->port.src = flow_keys.ports.src;
+		tuple->port.dst = flow_keys.ports.dst;
+	}
 	tuple->n_proto = flow_keys.basic.n_proto;
 	tuple->ip_proto = flow_keys.basic.ip_proto;