[NET_SCHED]: cls_flow: support classification based on VLAN tag

Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/pkt_cls.h

@@ -348,6 +348,7 @@ enum
 	FLOW_KEY_RTCLASSID,
 	FLOW_KEY_SKUID,
 	FLOW_KEY_SKGID,
+	FLOW_KEY_VLAN_TAG,
 	__FLOW_KEY_MAX,
 };
 

net/sched/cls_flow.c

@@ -19,6 +19,7 @@
 #include <linux/in.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
+#include <linux/if_vlan.h>
 
 #include <net/pkt_cls.h>
 #include <net/ip.h>
@@ -270,6 +271,15 @@ static u32 flow_get_skgid(const struct sk_buff *skb)
 	return 0;
 }
 
+static u32 flow_get_vlan_tag(const struct sk_buff *skb)
+{
+	u16 uninitialized_var(tag);
+
+	if (vlan_get_tag(skb, &tag) < 0)
+		return 0;
+	return tag & VLAN_VID_MASK;
+}
+
 static u32 flow_key_get(const struct sk_buff *skb, int key)
 {
 	switch (key) {
@@ -305,6 +315,8 @@ static u32 flow_key_get(const struct sk_buff *skb, int key)
 		return flow_get_skuid(skb);
 	case FLOW_KEY_SKGID:
 		return flow_get_skgid(skb);
+	case FLOW_KEY_VLAN_TAG:
+		return flow_get_vlan_tag(skb);
 	default:
 		WARN_ON(1);
 		return 0;