[PATCH net] ipv6: don't install anycast address for /128 addresses on routers

[PATCH net] ipv6: don't install anycast address for /128 addresses on routers

[Hannes Frederic Sowa]

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>
---
 net/ipv6/addrconf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6c16345..43c8220 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1677,7 +1677,7 @@ 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))
@@ -1688,7 +1688,7 @@ 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))
-- 
1.8.4.2

Re: [PATCH net] ipv6: don't install anycast address for /128 addresses on routers

[François-Xavier Le Bail]

On Mon, 1/6/14, Hannes Frederic Sowa <hannes@stressinduktion.org> wrote:

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

Exact !

BR,
François-Xavier

Re: [PATCH net] ipv6: don't install anycast address for /128 addresses on routers

[David Miller]

From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Date: Mon, 6 Jan 2014 17:53:14 +0100

> 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>

Applied, thank you.