diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/ChangeLog | 6 | ||||
| -rw-r--r-- | lib/sockopt.c | 53 |
2 files changed, 53 insertions, 6 deletions
diff --git a/lib/ChangeLog b/lib/ChangeLog index c94e5639..26b478bf 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 655ecdc0..6ddbded1 100644 --- a/lib/sockopt.c +++ b/lib/sockopt.c @@ -162,6 +162,16 @@ getsockopt_ipv6_ifindex (struct msghdr *msgh) * 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 @@ setsockopt_multicast_ipv4(int sock, #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 @@ setsockopt_multicast_ipv4(int sock, 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 @@ setsockopt_multicast_ipv4(int sock, struct in_addr m; struct ip_mreq mreq; + int ret; #ifdef HAVE_BSD_STRUCT_IP_MREQ_HACK if (ifindex) @@ -230,11 +259,23 @@ setsockopt_multicast_ipv4(int sock, 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: |