ipv6: don't install anycast address for /128 addresses on routers

It does not make sense to create an anycast address for an /128-prefix.
Suppress it.

As 32019e651c6fce ("ipv6: Do not leave router anycast address for /127
prefixes.") shows we also may not leave them, because we could accidentally
remove an anycast address the user has allocated or got added via another
prefix.

Cc: François-Xavier Le Bail <fx.lebail@yahoo.com>
Cc: Thomas Haller <thaller@redhat.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1a341f74aa3fcfff39fa0138248b79108429c449..f62c72b59f8e8832a76a855805dd0f432c3abff0 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1671,7 +1671,7 @@ void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr)
 static void addrconf_join_anycast(struct inet6_ifaddr *ifp)
 {
        struct in6_addr addr;
-       if (ifp->prefix_len == 127) /* RFC 6164 */
+       if (ifp->prefix_len >= 127) /* RFC 6164 */
                return;
        ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
        if (ipv6_addr_any(&addr))
@@ -1682,7 +1682,7 @@ static void addrconf_join_anycast(struct inet6_ifaddr *ifp)
 static void addrconf_leave_anycast(struct inet6_ifaddr *ifp)
 {
        struct in6_addr addr;
-       if (ifp->prefix_len == 127) /* RFC 6164 */
+       if (ifp->prefix_len >= 127) /* RFC 6164 */
                return;
        ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
        if (ipv6_addr_any(&addr))