2005-10-20 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
* sockopt.c: (setsockopt_multicast_ipv4) If IP_ADD_MEMBERSHIP
fails with errno equal to EADDRINUSE, then issue an info
message and try IP_DROP_MEMBERSHIP followed by IP_ADD_MEMBERSHIP.
diff --git a/lib/ChangeLog b/lib/ChangeLog
index c94e563..26b478b 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,5 +1,11 @@
2005-10-20 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
+ * sockopt.c: (setsockopt_multicast_ipv4) If IP_ADD_MEMBERSHIP
+ fails with errno equal to EADDRINUSE, then issue an info
+ message and try IP_DROP_MEMBERSHIP followed by IP_ADD_MEMBERSHIP.
+
+2005-10-20 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
+
* memory.c: (show_memory_vty) Omit zero statistics. Print separators
only if some non-zero stats have been printed in between.
(show_separator) New function to print a separator.
diff --git a/lib/sockopt.c b/lib/sockopt.c
index 655ecdc..6ddbded 100644
--- a/lib/sockopt.c
+++ b/lib/sockopt.c
@@ -162,6 +162,16 @@
* using a single socket. The limit is typically 20, derived from the
* original BSD multicast implementation. Some systems have
* mechanisms for increasing this limit.
+ *
+ * In many 4.4BSD-derived systems, multicast group operations are not
+ * allowed on interfaces that are not UP. Thus, a previous attempt to
+ * leave the group may have failed, leaving it still joined, and we
+ * drop/join quietly to recover. This may not be necessary, but aims to
+ * defend against unknown behavior in that we will still return an error
+ * if the second join fails. It is not clear how other systems
+ * (e.g. Linux, Solaris) behave when leaving groups on down interfaces,
+ * but this behavior should not be harmful if they behave the same way,
+ * allow leaves, or implicitly leave all groups joined to down interfaces.
*/
int
setsockopt_multicast_ipv4(int sock,
@@ -174,6 +184,7 @@
#ifdef HAVE_STRUCT_IP_MREQN_IMR_IFINDEX
/* This is better because it uses ifindex directly */
struct ip_mreqn mreqn;
+ int ret;
switch (optname)
{
@@ -190,7 +201,24 @@
else
mreqn.imr_address = if_addr;
- return setsockopt(sock, IPPROTO_IP, optname, (void *)&mreqn, sizeof(mreqn));
+ ret = setsockopt(sock, IPPROTO_IP, optname,
+ (void *)&mreqn, sizeof(mreqn));
+ if ((ret < 0) && (optname == IP_ADD_MEMBERSHIP) && (errno == EADDRINUSE))
+ {
+ /* see above: handle possible problem when interface comes back up */
+ char buf[2][INET_ADDRSTRLEN];
+ zlog_info("setsockopt_multicast_ipv4 attempting to drop and "
+ "re-add (fd %d, ifaddr %s, mcast %s, ifindex %u)",
+ sock,
+ inet_ntop(AF_INET, &if_addr, buf[0], sizeof(buf[0])),
+ inet_ntop(AF_INET, &mreqn.imr_multiaddr,
+ buf[1], sizeof(buf[1])), ifindex);
+ setsockopt(sock, IPPROTO_IP, IP_DROP_MEMBERSHIP,
+ (void *)&mreqn, sizeof(mreqn));
+ ret = setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
+ (void *)&mreqn, sizeof(mreqn));
+ }
+ return ret;
break;
default:
@@ -210,6 +238,7 @@
struct in_addr m;
struct ip_mreq mreq;
+ int ret;
#ifdef HAVE_BSD_STRUCT_IP_MREQ_HACK
if (ifindex)
@@ -230,11 +259,23 @@
mreq.imr_multiaddr.s_addr = mcast_addr;
mreq.imr_interface = m;
- return setsockopt (sock,
- IPPROTO_IP,
- optname,
- (void *)&mreq,
- sizeof(mreq));
+ ret = setsockopt (sock, IPPROTO_IP, optname, (void *)&mreq, sizeof(mreq));
+ if ((ret < 0) && (optname == IP_ADD_MEMBERSHIP) && (errno == EADDRINUSE))
+ {
+ /* see above: handle possible problem when interface comes back up */
+ char buf[2][INET_ADDRSTRLEN];
+ zlog_info("setsockopt_multicast_ipv4 attempting to drop and "
+ "re-add (fd %d, ifaddr %s, mcast %s, ifindex %u)",
+ sock,
+ inet_ntop(AF_INET, &if_addr, buf[0], sizeof(buf[0])),
+ inet_ntop(AF_INET, &mreq.imr_multiaddr,
+ buf[1], sizeof(buf[1])), ifindex);
+ setsockopt (sock, IPPROTO_IP, IP_DROP_MEMBERSHIP,
+ (void *)&mreq, sizeof(mreq));
+ ret = setsockopt (sock, IPPROTO_IP, IP_ADD_MEMBERSHIP,
+ (void *)&mreq, sizeof(mreq));
+ }
+ return ret;
break;
default: