net: Add VLAN ID to flow_keys

In flow_dissector set vlan_id in flow_keys when VLAN is found.
Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/flow_dissector.h

@@ -27,6 +27,10 @@ struct flow_dissector_key_basic {
 	u8	padding;
 };
 
+struct flow_dissector_key_tags {
+	u32	vlan_id:12;
+};
+
 /**
  * struct flow_dissector_key_ipv4_addrs:
  * @src: source ip address
@@ -106,6 +110,7 @@ enum flow_dissector_key_id {
 	FLOW_DISSECTOR_KEY_PORTS, /* struct flow_dissector_key_ports */
 	FLOW_DISSECTOR_KEY_ETH_ADDRS, /* struct flow_dissector_key_eth_addrs */
 	FLOW_DISSECTOR_KEY_TIPC_ADDRS, /* struct flow_dissector_key_tipc_addrs */
+	FLOW_DISSECTOR_KEY_VLANID, /* struct flow_dissector_key_flow_tags */
 
 	FLOW_DISSECTOR_KEY_MAX,
 };
@@ -142,6 +147,7 @@ struct flow_keys {
 	struct flow_dissector_key_control control;
 #define FLOW_KEYS_HASH_START_FIELD basic
 	struct flow_dissector_key_basic basic;
+	struct flow_dissector_key_tags tags;
 	struct flow_dissector_key_ports ports;
 	struct flow_dissector_key_addrs addrs;
 };

net/core/flow_dissector.c

@@ -126,6 +126,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
 	struct flow_dissector_key_basic *key_basic;
 	struct flow_dissector_key_addrs *key_addrs;
 	struct flow_dissector_key_ports *key_ports;
+	struct flow_dissector_key_tags *key_tags;
 	u8 ip_proto;
 
 	if (!data) {
@@ -246,6 +247,15 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
 		if (!vlan)
 			return false;
 
+		if (skb_flow_dissector_uses_key(flow_dissector,
+						FLOW_DISSECTOR_KEY_VLANID)) {
+			key_tags = skb_flow_dissector_target(flow_dissector,
+							     FLOW_DISSECTOR_KEY_VLANID,
+							     target_container);
+
+			key_tags->vlan_id = skb_vlan_tag_get_id(skb);
+		}
+
 		proto = vlan->h_vlan_encapsulated_proto;
 		nhoff += sizeof(*vlan);
 		goto again;
@@ -645,6 +655,10 @@ static const struct flow_dissector_key flow_keys_dissector_keys[] = {
 		.key_id = FLOW_DISSECTOR_KEY_PORTS,
 		.offset = offsetof(struct flow_keys, ports),
 	},
+	{
+		.key_id = FLOW_DISSECTOR_KEY_VLANID,
+		.offset = offsetof(struct flow_keys, tags),
+	},
 };
 
 static const struct flow_dissector_key flow_keys_buf_dissector_keys[] = {