+ if(listen(nfd, 3)) {
+ logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "listen", sockstrerror(sockerrno));
+ closesocket(nfd);
+ return -1;
+ }
+
+ return nfd;
+}
+
+int setup_udp_listen_socket(meshlink_handle_t *mesh, const struct addrinfo *aip) {
+ int nfd = socket(aip->ai_family, SOCK_DGRAM, IPPROTO_UDP);
+
+ if(nfd == -1) {
+ return -1;
+ }
+
+#ifdef FD_CLOEXEC
+ fcntl(nfd, F_SETFD, FD_CLOEXEC);
+#endif
+
+#ifdef O_NONBLOCK
+ int flags = fcntl(nfd, F_GETFL);
+
+ if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0) {
+ closesocket(nfd);
+ logger(mesh, MESHLINK_ERROR, "System call `%s' failed: %s", "fcntl", strerror(errno));
+ return -1;
+ }
+
+#elif defined(WIN32)
+ unsigned long arg = 1;
+
+ if(ioctlsocket(nfd, FIONBIO, &arg) != 0) {
+ closesocket(nfd);
+ logger(mesh, MESHLINK_ERROR, "Call to `%s' failed: %s", "ioctlsocket", sockstrerror(sockerrno));
+ return -1;
+ }
+
+#endif
+
+ int option = 1;
+ setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, (void *)&option, sizeof(option));
+ setsockopt(nfd, SOL_SOCKET, SO_BROADCAST, (void *)&option, sizeof(option));
+
+#if defined(IPV6_V6ONLY)
+
+ if(aip->ai_family == AF_INET6) {
+ setsockopt(nfd, IPPROTO_IPV6, IPV6_V6ONLY, (void *)&option, sizeof(option));
+ }
+
+#endif
+
+#if defined(IP_DONTFRAG) && !defined(IP_DONTFRAGMENT)
+#define IP_DONTFRAGMENT IP_DONTFRAG
+#endif
+
+#if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DO)
+ option = IP_PMTUDISC_DO;
+ setsockopt(nfd, IPPROTO_IP, IP_MTU_DISCOVER, (void *)&option, sizeof(option));
+#elif defined(IP_DONTFRAGMENT)
+ option = 1;
+ setsockopt(nfd, IPPROTO_IP, IP_DONTFRAGMENT, (void *)&option, sizeof(option));
+#endif
+
+ if(aip->ai_family == AF_INET6) {
+#if defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DO)
+ option = IPV6_PMTUDISC_DO;
+ setsockopt(nfd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, (void *)&option, sizeof(option));
+#elif defined(IPV6_DONTFRAG)
+ option = 1;
+ setsockopt(nfd, IPPROTO_IPV6, IPV6_DONTFRAG, (void *)&option, sizeof(option));
+#endif
+ }
+
+ if(bind(nfd, aip->ai_addr, aip->ai_addrlen)) {
+ closesocket(nfd);
+ return -1;
+ }
+
+ return nfd;
+}
+
+/*
+ Add listening sockets.
+*/
+static bool add_listen_sockets(meshlink_handle_t *mesh) {