datapath: backport: vlan: Check for vlan ethernet types for 8021.q or…

… 802.1ad

Upstream commit:
    commit fe19c4f971a55cea3be442d8032a5f6021702791
    Author: Eric Garver <[email protected]>
    Date:   Wed Sep 7 12:56:58 2016 -0400

    This is to simplify using double tagged vlans. This function allows all
    valid vlan ethertypes to be checked in a single function call.
    Also replace some instances that check for both ETH_P_8021Q and
    ETH_P_8021AD.

    Patch based on one originally by Thomas F Herbert.

    Signed-off-by: Thomas F Herbert <[email protected]>
    Signed-off-by: Eric Garver <[email protected]>
    Acked-by: Pravin B Shelar <[email protected]>
    Signed-off-by: David S. Miller <[email protected]>

Signed-off-by: Yi Yang <[email protected]>
Acked-by: Eric Garver <[email protected]>
Signed-off-by: Joe Stringer <[email protected]>

acinclude.m4

@@ -664,6 +664,7 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
   OVS_GREP_IFELSE([$KSRC/include/linux/if_vlan.h], [__vlan_insert_tag])
   OVS_GREP_IFELSE([$KSRC/include/linux/if_vlan.h], [vlan_get_protocol])
   OVS_GREP_IFELSE([$KSRC/include/linux/if_vlan.h], [skb_vlan_tagged])
+  OVS_GREP_IFELSE([$KSRC/include/linux/if_vlan.h], [eth_type_vlan])
 
   OVS_GREP_IFELSE([$KSRC/include/linux/u64_stats_sync.h], [u64_stats_fetch_begin_irq])
 

datapath/linux/compat/include/linux/if_vlan.h

@@ -101,6 +101,25 @@ static inline struct sk_buff *rpl___vlan_hwaccel_put_tag(struct sk_buff *skb,
 #define __vlan_hwaccel_put_tag rpl___vlan_hwaccel_put_tag
 #endif
 
+#ifndef HAVE_ETH_TYPE_VLAN
+/**
+ * eth_type_vlan - check for valid vlan ether type.
+ * @ethertype: ether type to check
+ *
+ * Returns true if the ether type is a vlan ether type.
+ */
+static inline bool eth_type_vlan(__be16 ethertype)
+{
+	switch (ethertype) {
+	case htons(ETH_P_8021Q):
+	case htons(ETH_P_8021AD):
+		return true;
+	default:
+		return false;
+	}
+}
+#endif
+
 /* All of these were introduced in a single commit preceding 2.6.33, so
  * presumably all of them or none of them are present. */
 #ifndef VLAN_PRIO_MASK
@@ -189,7 +208,7 @@ static inline __be16 __vlan_get_protocol(struct sk_buff *skb, __be16 type,
 	 * present at mac_len - VLAN_HLEN (if mac_len > 0), or at
 	 * ETH_HLEN otherwise
 	 */
-	if (type == htons(ETH_P_8021Q) || type == htons(ETH_P_8021AD)) {
+	if (eth_type_vlan(type)) {
 		if (vlan_depth) {
 			if (WARN_ON(vlan_depth < VLAN_HLEN))
 				return 0;
@@ -207,8 +226,7 @@ static inline __be16 __vlan_get_protocol(struct sk_buff *skb, __be16 type,
 			vh = (struct vlan_hdr *)(skb->data + vlan_depth);
 			type = vh->h_vlan_encapsulated_proto;
 			vlan_depth += VLAN_HLEN;
-		} while (type == htons(ETH_P_8021Q) ||
-			 type == htons(ETH_P_8021AD));
+		} while (eth_type_vlan(type));
 	}
 
 	if (depth)
@@ -242,8 +260,7 @@ static inline __be16 vlan_get_protocol(struct sk_buff *skb)
 static inline bool skb_vlan_tagged(const struct sk_buff *skb)
 {
 	if (!skb_vlan_tag_present(skb) &&
-	    likely(skb->protocol != htons(ETH_P_8021Q) &&
-		   skb->protocol != htons(ETH_P_8021AD)))
+	    likely(!eth_type_vlan(skb->protocol)))
 		return false;
 
 	return true;
@@ -263,15 +280,14 @@ static inline bool skb_vlan_tagged_multi(const struct sk_buff *skb)
 	if (!skb_vlan_tag_present(skb)) {
 		struct vlan_ethhdr *veh;
 
-		if (likely(protocol != htons(ETH_P_8021Q) &&
-			   protocol != htons(ETH_P_8021AD)))
+		if (likely(!eth_type_vlan(protocol)))
 			return false;
 
 		veh = (struct vlan_ethhdr *)skb->data;
 		protocol = veh->h_vlan_encapsulated_proto;
 	}
 
-	if (protocol != htons(ETH_P_8021Q) && protocol != htons(ETH_P_8021AD))
+	if (!eth_type_vlan(protocol))
 		return false;
 
 	return true;