netfilter: nft_payload: add VLAN offload support

Match on ethertype and set up protocol dependency. Check for protocol
dependency before accessing the tci field. Allow to match on the
encapsulated ethertype too.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/flow_dissector.h

@@ -48,9 +48,12 @@ struct flow_dissector_key_tags {
 };
 
 struct flow_dissector_key_vlan {
-	u16	vlan_id:12,
-		vlan_dei:1,
-		vlan_priority:3;
+	union {
+		u16	vlan_id:12,
+			vlan_dei:1,
+			vlan_priority:3;
+		__be16	vlan_tci;
+	};
 	__be16	vlan_tpid;
 };
 

net/netfilter/nft_payload.c

@@ -182,6 +182,28 @@ static int nft_payload_offload_ll(struct nft_offload_ctx *ctx,
 		NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_ETH_ADDRS, eth_addrs,
 				  dst, ETH_ALEN, reg);
 		break;
+	case offsetof(struct ethhdr, h_proto):
+		if (priv->len != sizeof(__be16))
+			return -EOPNOTSUPP;
+
+		NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_BASIC, basic,
+				  n_proto, sizeof(__be16), reg);
+		nft_offload_set_dependency(ctx, NFT_OFFLOAD_DEP_NETWORK);
+		break;
+	case offsetof(struct vlan_ethhdr, h_vlan_TCI):
+		if (priv->len != sizeof(__be16))
+			return -EOPNOTSUPP;
+
+		NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_VLAN, vlan,
+				  vlan_tci, sizeof(__be16), reg);
+		break;
+	case offsetof(struct vlan_ethhdr, h_vlan_encapsulated_proto):
+		if (priv->len != sizeof(__be16))
+			return -EOPNOTSUPP;
+
+		NFT_OFFLOAD_MATCH(FLOW_DISSECTOR_KEY_VLAN, vlan,
+				  vlan_tpid, sizeof(__be16), reg);
+		break;
 	default:
 		return -EOPNOTSUPP;
 	}