net/flow_dissector: Save vlan ethertype from headers

Change vlan dissector key to save vlan tpid to support both 802.1Q
and 802.1AD ethertype.
Signed-off-by: Jianbo Liu <jianbol@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/flow_dissector.h

@@ -47,7 +47,7 @@ struct flow_dissector_key_tags {
 struct flow_dissector_key_vlan {
 	u16	vlan_id:12,
 		vlan_priority:3;
-	u16	padding;
+	__be16	vlan_tpid;
 };
 
 struct flow_dissector_key_mpls {

net/core/flow_dissector.c

@@ -751,6 +751,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
 		const struct vlan_hdr *vlan;
 		struct vlan_hdr _vlan;
 		bool vlan_tag_present = skb && skb_vlan_tag_present(skb);
+		__be16 saved_vlan_tpid = proto;
 
 		if (vlan_tag_present)
 			proto = skb->protocol;
@@ -789,6 +790,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
 					(ntohs(vlan->h_vlan_TCI) &
 					 VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
 			}
+			key_vlan->vlan_tpid = saved_vlan_tpid;
 		}
 
 		fdret = FLOW_DISSECT_RET_PROTO_AGAIN;