+#elif defined(IP_SENDSRCADDR)
+ if (src_address) {
+ struct in_addr *addr;
+
+ memset(cmsg_data, 0, sizeof(cmsg_data));
+ msg.msg_control = cmsg_data;
+ msg.msg_controllen = sizeof(cmsg_data);
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_addr));
+ cmsg->cmsg_level = IPPROTO_IP;
+ cmsg->cmsg_type = IP_SENDSRCADDR;
+
+ addr = (struct in_addr *)CMSG_DATA(cmsg);
+ addr->s_addr = src_address->address;
+
+ msg.msg_controllen = cmsg->cmsg_len;
+}
+#elif defined(IP_MULTICAST_IF)
+ {
+ struct in_addr any = { INADDR_ANY };
+ if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_IF, src_address ? (const void*) &src_address->address : (const void*) &any, sizeof(struct in_addr)) < 0) {
+ avahi_log_warn("IP_MULTICAST_IF failed: %s", strerror(errno));
+ return -1;
+ }
+ }
+#elif defined(__GNUC__)
+#warning "FIXME: We need some code to set the outgoing interface/local address here if IP_PKTINFO/IP_MULTICAST_IF is not available"