net: vxlan: add macro definition for number of IANA VXLAN-GPE port

Add macro definition for number of IANA VXLAN-GPE port for generic use.
Signed-off-by: Hao Chen <chenhao288@hisilicon.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -3747,7 +3747,7 @@ static int vxlan_config_validate(struct net *src_net, struct vxlan_config *conf,
 
 	if (!conf->dst_port) {
 		if (conf->flags & VXLAN_F_GPE)
-			conf->dst_port = htons(4790); /* IANA VXLAN-GPE port */
+			conf->dst_port = htons(IANA_VXLAN_GPE_UDP_PORT);
 		else
 			conf->dst_port = htons(vxlan_port);
 	}

include/net/vxlan.h

@@ -10,6 +10,7 @@
 #include <net/nexthop.h>
 
 #define IANA_VXLAN_UDP_PORT     4789
+#define IANA_VXLAN_GPE_UDP_PORT 4790
 
 /* VXLAN protocol (RFC 7348) header:
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+