diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 448eccb..b24508a 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -269,18 +269,21 @@
 	buf[0] = 0x00;
 }
 
-static inline void ipv6_ib_mc_map(struct in6_addr *addr, char *buf)
+static inline void ipv6_ib_mc_map(const struct in6_addr *addr,
+				  const unsigned char *broadcast, char *buf)
 {
+	unsigned char scope = broadcast[5] & 0xF;
+
 	buf[0]  = 0;		/* Reserved */
 	buf[1]  = 0xff;		/* Multicast QPN */
 	buf[2]  = 0xff;
 	buf[3]  = 0xff;
 	buf[4]  = 0xff;
-	buf[5]  = 0x12;		/* link local scope */
+	buf[5]  = 0x10 | scope;	/* scope from broadcast address */
 	buf[6]  = 0x60;		/* IPv6 signature */
 	buf[7]  = 0x1b;
-	buf[8]  = 0;		/* P_Key */
-	buf[9]  = 0;
+	buf[8]  = broadcast[8];	/* P_Key */
+	buf[9]  = broadcast[9];
 	memcpy(buf + 10, addr->s6_addr + 6, 10);
 }
 #endif