Really ripngd should either leave groups on down interfaces, or keep
track of on which interfaces joins have occurred. This is complicated
by the possible lack of a clear behavior spec on whether interfaces
keep their joined group lists across a down/up/down transition. (On
NetBSD, they do.)
2004-01-03 Greg Troxel <gdt@ahi.ir.bbn.com>
* ripng_interface.c (ripng_multicast_join): If IPV6_JOIN_GROUP
returns EADDRINUSE, consider the join successful. This happens
when an interface goes down and comes back because
ripng_multicast_leave does not invoke the LEAVE_GROUP operation if
the interface is down. Solves problem of ripng stopping working
on an interface which goes down and then comes back up (on NetBSD).
diff --git a/ripngd/ChangeLog b/ripngd/ChangeLog
index fa13510..f5a3078 100644
--- a/ripngd/ChangeLog
+++ b/ripngd/ChangeLog
@@ -1,3 +1,12 @@
+2004-01-03 Greg Troxel <gdt@ahi.ir.bbn.com>
+
+ * ripng_interface.c (ripng_multicast_join): If IPV6_JOIN_GROUP
+ returns EADDRINUSE, consider the join successful. This happens
+ when an interface goes down and comes back because
+ ripng_multicast_leave does not invoke the LEAVE_GROUP operation if
+ the interface is down. Solves problem of ripng stopping working
+ on an interface which goes down and then comes back up (on NetBSD).
+
2003-05-25 Hasso Tepper <hasso@estpak.ee>
* Revert ripng_ifrmap stuff because ripd uses it now as well.
diff --git a/ripngd/ripng_interface.c b/ripngd/ripng_interface.c
index b4299eb..7437f70 100644
--- a/ripngd/ripng_interface.c
+++ b/ripngd/ripng_interface.c
@@ -67,6 +67,18 @@
ret = setsockopt (ripng->sock, IPPROTO_IPV6, IPV6_JOIN_GROUP,
(char *) &mreq, sizeof (mreq));
+
+ if (ret < 0 && errno == EADDRINUSE)
+ {
+ /*
+ * Group is already joined. This occurs due to sloppy group
+ * management, in particular declining to leave the group on
+ * an interface that has just gone down.
+ */
+ zlog_warn ("ripng join on %s EADDRINUSE (ignoring)\n", ifp->name);
+ return 0; /* not an error */
+ }
+
if (ret < 0)
zlog_warn ("can't setsockopt IPV6_JOIN_GROUP: %s", strerror (errno));