clusterer_controller: a socket drops other groups' multicast from the moment it is bound

IP_MULTICAST_ALL was cleared after bind() and IP_ADD_MEMBERSHIP, so the
second cluster's socket on a shared port could queue the first cluster's
multicast in between; its worker then forwarded the packet to the first
cluster's worker, which had it already and logged it as a replay
(netns group 8 under ASan, a node restarting while its first cluster was
busy).  The option is now set before bind().

Author: Lt-Flash

modules-contrib/clusterer_controller/cl_ctr_wire.c

@@ -225,6 +225,19 @@ int cl_ctr_setup_socket(cl_ctr_cluster_t *cl)
 	}
     }
 
+#ifdef IP_MULTICAST_ALL
+    /* Linux delivers every group joined on this port host-wide by default, so
+     * sibling clusters would read each other's multicast; must precede bind() */
+    {
+	int mc_all = 0;
+	if (setsockopt(sock, IPPROTO_IP, IP_MULTICAST_ALL,
+	               &mc_all, sizeof(mc_all)) < 0)
+	    LM_WARN("clusterer_controller: [cluster %d] IP_MULTICAST_ALL: %s - "
+	            "this socket may also receive other groups joined on port %d\n",
+	            cl->cluster_id, strerror(errno), cl->multicast_port);
+    }
+#endif
+
     if (bind(sock, (struct sockaddr *)&local, sizeof(local)) < 0) {
 	LM_ERR("clusterer_controller: bind() port %d: %s\n",
 	       cl->multicast_port, strerror(errno));
@@ -246,19 +259,6 @@ int cl_ctr_setup_socket(cl_ctr_cluster_t *cl)
 	return -1;
     }
 
-#ifdef IP_MULTICAST_ALL
-    /* Linux delivers every group joined on this port host-wide by default, so
-     * sibling clusters would read each other's multicast */
-    {
-	int mc_all = 0;
-	if (setsockopt(sock, IPPROTO_IP, IP_MULTICAST_ALL,
-	               &mc_all, sizeof(mc_all)) < 0)
-	    LM_WARN("clusterer_controller: [cluster %d] IP_MULTICAST_ALL: %s - "
-	            "this socket may also receive other groups joined on port %d\n",
-	            cl->cluster_id, strerror(errno), cl->multicast_port);
-    }
-#endif
-
     if (setsockopt(sock, IPPROTO_IP, IP_MULTICAST_LOOP,
                    &loop, sizeof(loop)) < 0)
 	LM_WARN("clusterer_controller: IP_MULTICAST_LOOP: %s\n",