net/if.h: add some missing IFF_ constants

include/net/if.h

@@ -43,6 +43,11 @@ void if_freenameindex (struct if_nameindex *);
 #define IFF_PORTSEL 0x2000
 #define IFF_AUTOMEDIA 0x4000
 #define IFF_DYNAMIC 0x8000
+#define IFF_LOWER_UP 0x10000
+#define IFF_DORMANT 0x20000
+#define IFF_ECHO 0x40000
+#define IFF_VOLATILE (IFF_LOOPBACK|IFF_POINTOPOINT|IFF_BROADCAST| \
+        IFF_ECHO|IFF_MASTER|IFF_SLAVE|IFF_RUNNING|IFF_LOWER_UP|IFF_DORMANT)
 
 struct ifaddr {
 	struct sockaddr ifa_addr;