- mdns_mcast_group_ipv4 (&sa);
-
- memset(&mreq, 0, sizeof(mreq));
- mreq.imr_multiaddr = sa.sin_addr;
- mreq.imr_ifindex = index;
-
- if (setsockopt(fd, SOL_IP, IP_DROP_MEMBERSHIP, &mreq, sizeof(mreq)) < 0) {
- g_warning("IP_DROP_MEMBERSHIP failed: %s\n", strerror(errno));
- return -1;
+ assert(fd >= 0);
+ assert(sa);
+ assert(l > 0);
+
+ if (bind(fd, sa, l) < 0) {
+
+ if (errno != EADDRINUSE) {
+ avahi_log_warn("bind() failed: %s", strerror(errno));
+ return -1;
+ }
+
+ avahi_log_warn("*** WARNING: Detected another %s mDNS stack running on this host. This makes mDNS unreliable and is thus not recommended. ***",
+ sa->sa_family == AF_INET ? "IPv4" : "IPv6");
+
+ /* Try again, this time with SO_REUSEADDR set */
+ yes = 1;
+ if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
+ avahi_log_warn("SO_REUSEADDR failed: %s", strerror(errno));
+ return -1;
+ }
+
+ if (bind(fd, sa, l) < 0) {
+ avahi_log_warn("bind() failed: %s", strerror(errno));
+ return -1;
+ }
+ } else {
+
+ /* We enable SO_REUSEADDR afterwards, to make sure that the
+ * user may run other mDNS implementations if he really
+ * wants. */
+
+ yes = 1;
+ if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) < 0) {
+ avahi_log_warn("SO_REUSEADDR failed: %s", strerror(errno));
+ return -1;
+ }