diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 9059e0e..9573c8d 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -377,6 +377,12 @@
 		 a->s6_addr32[2] | a->s6_addr32[3] ) == 0); 
 }
 
+static inline int ipv6_addr_v4mapped(const struct in6_addr *a)
+{
+	return ((a->s6_addr32[0] | a->s6_addr32[1]) == 0 &&
+		 a->s6_addr32[2] == htonl(0x0000ffff));
+}
+
 /*
  * find the first different bit between two addresses
  * length of address must be a multiple of 32bits