ipv6: Add IPv6 multicast address flag defines

This commit adds the missing IPv6 multicast address flag defines to
complement the already existing multicast address scope defines and to
be able to check these flags nicely in the future.
Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -88,6 +88,18 @@
 #define IPV6_ADDR_SCOPE_ORGLOCAL	0x08
 #define IPV6_ADDR_SCOPE_GLOBAL		0x0e
 
+/*
+ *	Addr flags
+ */
+#ifdef __KERNEL__
+#define IPV6_ADDR_MC_FLAG_TRANSIENT(a)	\
+	((a)->s6_addr[1] & 0x10)
+#define IPV6_ADDR_MC_FLAG_PREFIX(a)	\
+	((a)->s6_addr[1] & 0x20)
+#define IPV6_ADDR_MC_FLAG_RENDEZVOUS(a)	\
+	((a)->s6_addr[1] & 0x40)
+#endif
+
 /*
  *	fragmentation header
  */