[PATCH] IPV6: DAD has to be destined to solicited node mulitcast address

[YOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@xxxxxxxxxxxxxx>]

Hello.

Check if DAD is destined for solicited node multicast address
as RFC2461 required.

Thanks in advance.

Index: linux-2.5/net/ipv6/ndisc.c
===================================================================
RCS file: /home/cvs/linux-2.5/net/ipv6/ndisc.c,v
retrieving revision 1.40
diff -u -r1.40 ndisc.c
--- linux-2.5/net/ipv6/ndisc.c  21 Jun 2003 16:21:01 -0000      1.40
+++ linux-2.5/net/ipv6/ndisc.c  25 Jun 2003 17:45:08 -0000
@@ -713,6 +713,7 @@
        struct net_device *dev = skb->dev;
        struct inet6_ifaddr *ifp;
        struct neighbour *neigh;
+       int addr_type = ipv6_addr_type(saddr);
 
        if (ipv6_addr_type(&msg->target)&IPV6_ADDR_MULTICAST) {
                if (net_ratelimit())
@@ -720,6 +721,20 @@
                return;
        }
 
+       /*
+        * RFC2461 7.1.1:
+        * DAD has to be destined for solicited node multicast address.
+        */
+       if (addr_type == IPV6_ADDR_ANY &&
+           !(daddr->s6_addr32[0] == htonl(0xff020000) &&
+             daddr->s6_addr32[1] == htonl(0x00000000) &&
+             daddr->s6_addr32[2] == htonl(0x00000001) &&
+             daddr->s6_addr [12] == 0xff )) {
+               if (net_ratelimit())
+                       printk(KERN_DEBUG "ICMP6 NS: bad DAD packet (wrong 
destination\n");
+               return;
+       }
+
        if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts)) {
                if (net_ratelimit())
                        printk(KERN_WARNING "ICMP NS: invalid ND option, 
ignored.\n");
@@ -743,14 +758,7 @@
         *      NOTE! Linux kernel < 2.4.4 broke this rule.
         */
                        
-       /* XXX: RFC2461 7.1.1:
-        *      If the IP source address is the unspecified address, the IP
-        *      destination address MUST be a solicited-node multicast address.
-        */
-
        if ((ifp = ipv6_get_ifaddr(&msg->target, dev)) != NULL) {
-               int addr_type = ipv6_addr_type(saddr);
-
                if (ifp->flags & IFA_F_TENTATIVE) {
                        /* Address is tentative. If the source
                           is unspecified address, it is someone
@@ -816,7 +824,6 @@
                in6_ifa_put(ifp);
        } else if (ipv6_chk_acast_addr(dev, &msg->target)) {
                struct inet6_dev *idev = in6_dev_get(dev);
-               int addr_type = ipv6_addr_type(saddr);
        
                /* anycast */
        

-- 
Hideaki YOSHIFUJI @ USAGI Project <yoshfuji@xxxxxxxxxxxxxx>
GPG FP: 9022 65EB 1ECF 3AD1 0BDF  80D8 4807 F894 E062 0EEA