ipv6: respect slaac hwaddr to really use the hwaddr

If the interface has one, otherwise it will fall back to using
the first ipv6 link-local address as before.

diff --git a/src/ipv6.c b/src/ipv6.c
index 30f376522d6286f7f815ea5f39b3572d7e7a2e9b..81249a6a657515f8703d003fe25529b945187720 100644 (file)
--- a/src/ipv6.c
+++ b/src/ipv6.c
@@ -227,6 +227,49 @@ ipv6_reserved(const struct in6_addr *addr)
        return false;
 }
 
+static int
+ipv6_makehwaddr(struct in6_addr *addr,
+    const struct in6_addr *prefix, int prefix_len, const struct interface *ifp)
+{
+
+       if (prefix_len > 64) {
+               errno = EINVAL;
+               return -1;
+       }
+
+       memcpy(addr->s6_addr, prefix->s6_addr, 8);
+       switch (ifp->hwtype) {
+       case ARPHRD_ETHER:
+               if (ifp->hwlen == 6) {
+                       addr->s6_addr[ 8] = ifp->hwaddr[0];
+                       addr->s6_addr[ 9] = ifp->hwaddr[1];
+                       addr->s6_addr[10] = ifp->hwaddr[2];
+                       addr->s6_addr[11] = 0xff;
+                       addr->s6_addr[12] = 0xfe;
+                       addr->s6_addr[13] = ifp->hwaddr[3];
+                       addr->s6_addr[14] = ifp->hwaddr[4];
+                       addr->s6_addr[15] = ifp->hwaddr[5];
+               } else if (ifp->hwlen == 8)
+                       memcpy(&addr->s6_addr[8], ifp->hwaddr, 8);
+               else {
+                       errno = ENOTSUP;
+                       return -1;
+               }
+               break;
+       default:
+               errno = ENOTSUP;
+               return -1;
+       }
+
+       /* Sanity check: g bit must not indciate "group" */
+       if (EUI64_GROUP(addr)) {
+               errno = EINVAL;
+               return -1;
+       }
+       EUI64_TO_IFID(addr);
+       return 0;
+}
+
 /* RFC7217 */
 static int
 ipv6_makestableprivate1(struct dhcpcd_ctx *ctx,
@@ -480,18 +523,25 @@ ipv6_makeaddr(struct in6_addr *addr, struct interface *ifp,
                errno = EINVAL;
                return -1;
        }
-       if ((ap = ipv6_linklocal(ifp)) == NULL) {
-               /* We delay a few functions until we get a local-link address
-                * so this should never be hit. */
-               errno = ENOENT;
-               return -1;
+
+       /* If we don't have a hardware address, then use the first link-local
+        * address to base it on. */
+       if (ifp->hwlen == 0) {
+               if ((ap = ipv6_linklocal(ifp)) == NULL) {
+                       /* We delay a few functions until we get a local-link address
+                        * so this should never be hit. */
+                       errno = ENOENT;
+                       return -1;
+               }
+
+               /* Make the address from the first local-link address */
+               memcpy(addr, prefix, sizeof(*prefix));
+               addr->s6_addr32[2] = ap->addr.s6_addr32[2];
+               addr->s6_addr32[3] = ap->addr.s6_addr32[3];
+               return 0;
        }
 
-       /* Make the address from the first local-link address */
-       memcpy(addr, prefix, sizeof(*prefix));
-       addr->s6_addr32[2] = ap->addr.s6_addr32[2];
-       addr->s6_addr32[3] = ap->addr.s6_addr32[3];
-       return 0;
+       return ipv6_makehwaddr(addr, prefix, prefix_len, ifp);
 }
 
 static void
@@ -1467,36 +1517,10 @@ nextslaacprivate:
                        return -1;
                }
                ap->dadcounter = dadcounter;
-       } else {
-               memcpy(ap->addr.s6_addr, ap->prefix.s6_addr, 8);
-               switch (ifp->hwtype) {
-               case ARPHRD_ETHER:
-                       if (ifp->hwlen == 6) {
-                               ap->addr.s6_addr[ 8] = ifp->hwaddr[0];
-                               ap->addr.s6_addr[ 9] = ifp->hwaddr[1];
-                               ap->addr.s6_addr[10] = ifp->hwaddr[2];
-                               ap->addr.s6_addr[11] = 0xff;
-                               ap->addr.s6_addr[12] = 0xfe;
-                               ap->addr.s6_addr[13] = ifp->hwaddr[3];
-                               ap->addr.s6_addr[14] = ifp->hwaddr[4];
-                               ap->addr.s6_addr[15] = ifp->hwaddr[5];
-                       } else if (ifp->hwlen == 8)
-                               memcpy(&ap->addr.s6_addr[8], ifp->hwaddr, 8);
-                       else {
-                               free(ap);
-                               errno = ENOTSUP;
-                               return -1;
-                       }
-                       break;
-               }
-
-               /* Sanity check: g bit must not indciate "group" */
-               if (EUI64_GROUP(&ap->addr)) {
-                       free(ap);
-                       errno = EINVAL;
-                       return -1;
-               }
-               EUI64_TO_IFID(&ap->addr);
+       } else if (ipv6_makehwaddr(&ap->addr,
+           &ap->prefix, ap->prefix_len, ifp) == -1) {
+               free(ap);
+               return -1;
        }
 
        /* Do we already have this address? */