[PKT_SCHED]: vlan tag match

Provide a way to use tc filters on vlan tag even if tag is buried in
skb due to hardware acceleration.

Signed-off-by: Stephen Hemminger <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/pkt_cls.h

···
 #define	TCF_EM_U32		3
 #define	TCF_EM_META		4
 #define	TCF_EM_TEXT		5
-#define	TCF_EM_MAX		5
+#define        TCF_EM_VLAN		6
+#define	TCF_EM_MAX		6
 
 enum
 {

include/linux/tc_ematch/tc_em_meta.h

···
  	TCF_META_ID_SK_SNDTIMEO,
  	TCF_META_ID_SK_SENDMSG_OFF,
  	TCF_META_ID_SK_WRITE_PENDING,
+	TCF_META_ID_VLAN_TAG,
 	__TCF_META_ID_MAX
 };
 #define TCF_META_ID_MAX (__TCF_META_ID_MAX - 1)

net/sched/em_meta.c

···
 #include <linux/string.h>
 #include <linux/skbuff.h>
 #include <linux/random.h>
+#include <linux/if_vlan.h>
 #include <linux/tc_ematch/tc_em_meta.h>
 #include <net/dst.h>
 #include <net/route.h>
···
 {
 	*err = var_dev(skb->dev, dst);
 }
+
+/**************************************************************************
+ * vlan tag
+ **************************************************************************/
+
+META_COLLECTOR(int_vlan_tag)
+{
+	unsigned short tag;
+	if (vlan_get_tag(skb, &tag) < 0)
+		*err = -1;
+	else
+		dst->value = tag;
+}
+
+
 
 /**************************************************************************
  * skb attributes
···
 		[META_ID(SK_SNDTIMEO)]		= META_FUNC(int_sk_sndtimeo),
 		[META_ID(SK_SENDMSG_OFF)]	= META_FUNC(int_sk_sendmsg_off),
 		[META_ID(SK_WRITE_PENDING)]	= META_FUNC(int_sk_write_pend),
+		[META_ID(VLAN_TAG)]		= META_FUNC(int_vlan_tag),
 	}
 };