ipv6: Introduce ipv6_addr_is_solict_mult() to check Solicited Node Multicast Addresses.

Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/addrconf.h

@@ -305,6 +305,14 @@ static inline bool ipv6_addr_is_isatap(const struct in6_addr *addr)
 	return (addr->s6_addr32[2] | htonl(0x02000000)) == htonl(0x02005EFE);
 }
 
+static inline bool ipv6_addr_is_solict_mult(const struct in6_addr *addr)
+{
+	return (addr->s6_addr32[0] == htonl(0xff020000) &&
+		addr->s6_addr32[1] == htonl(0x00000000) &&
+		addr->s6_addr32[2] == htonl(0x00000001) &&
+		addr->s6_addr[12] == 0xff);
+}
+
 #ifdef CONFIG_PROC_FS
 extern int if6_proc_init(void);
 extern void if6_proc_exit(void);

net/ipv6/ndisc.c

@@ -685,11 +685,7 @@ static void ndisc_recv_ns(struct sk_buff *skb)
 	 * RFC2461 7.1.1:
 	 * DAD has to be destined for solicited node multicast address.
 	 */
-	if (dad &&
-	    !(daddr->s6_addr32[0] == htonl(0xff020000) &&
-	      daddr->s6_addr32[1] == htonl(0x00000000) &&
-	      daddr->s6_addr32[2] == htonl(0x00000001) &&
-	      daddr->s6_addr [12] == 0xff )) {
+	if (dad && !ipv6_addr_is_solict_mult(daddr)) {
 		ND_PRINTK(2, warn, "NS: bad DAD packet (wrong destination)\n");
 		return;
 	}