vxlan: support both IPv4 and IPv6 sockets in a single vxlan device

For metadata based vxlan interface, open both IPv4 and IPv6 socket. This is
much more user friendly: it's not necessary to create two vxlan interfaces
and pay attention to using the right one in routing rules.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index 480a319..c1c899c 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -152,7 +152,10 @@
 struct vxlan_dev {
 	struct hlist_node hlist;	/* vni hash table */
 	struct list_head  next;		/* vxlan's per namespace list */
-	struct vxlan_sock *vn_sock;	/* listening socket */
+	struct vxlan_sock *vn4_sock;	/* listening socket for IPv4 */
+#if IS_ENABLED(CONFIG_IPV6)
+	struct vxlan_sock *vn6_sock;	/* listening socket for IPv6 */
+#endif
 	struct net_device *dev;
 	struct net	  *net;		/* netns for packet i/o */
 	struct vxlan_rdst default_dst;	/* default destination */
@@ -195,9 +198,14 @@
 struct net_device *vxlan_dev_create(struct net *net, const char *name,
 				    u8 name_assign_type, struct vxlan_config *conf);
 
-static inline __be16 vxlan_dev_dst_port(struct vxlan_dev *vxlan)
+static inline __be16 vxlan_dev_dst_port(struct vxlan_dev *vxlan,
+					unsigned short family)
 {
-	return inet_sk(vxlan->vn_sock->sock->sk)->inet_sport;
+#if IS_ENABLED(CONFIG_IPV6)
+	if (family == AF_INET6)
+		return inet_sk(vxlan->vn6_sock->sock->sk)->inet_sport;
+#endif
+	return inet_sk(vxlan->vn4_sock->sock->sk)->inet_sport;
 }
 
 static inline netdev_features_t vxlan_features_check(struct sk_buff *skb,