+ }
+}
+
+static void mdns_io_handler(event_loop_t *loop, void *data, int flags) {
+ (void)flags;
+ meshlink_handle_t *mesh = loop->data;
+ io_t *io = data;
+ uint8_t buf[1024];
+ sockaddr_t sa;
+ socklen_t sl = sizeof(sa);
+
+#ifdef IP_PKTINFO
+ struct iovec iov = {
+ .iov_base = buf,
+ .iov_len = sizeof(buf),
+ };
+
+ union {
+ char buf[1024];
+ struct cmsghdr align;
+ } u;
+
+ struct msghdr msg = {
+ .msg_name = &sa,
+ .msg_namelen = sl,
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
+ .msg_control = u.buf,
+ .msg_controllen = sizeof(u.buf),
+ };
+
+ ssize_t len = recvmsg(io->fd, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
+
+ sl = msg.msg_namelen;
+#else
+ ssize_t len = recvfrom(io->fd, buf, sizeof(buf), MSG_DONTWAIT, &sa.sa, &sl);
+#endif
+
+ if(len == -1) {
+ if(!sockwouldblock(errno)) {
+ logger(mesh, MESHLINK_ERROR, "Error reading from mDNS discovery socket: %s", strerror(errno));
+ io_set(loop, io, 0);
+ }
+
+ return;
+ }
+
+ char *name = NULL;
+ uint16_t port = 0;
+ const char *keys[2] = {MESHLINK_MDNS_NAME_KEY, MESHLINK_MDNS_FINGERPRINT_KEY};
+ char *values[2] = {NULL, NULL};
+
+ if(parse_response(buf, len, &name, mesh->appname, "tcp", &port, 2, keys, values)) {
+ node_t *n = (node_t *)meshlink_get_node(mesh, values[0]);
+
+ if(n) {
+ if(n != mesh->self) {
+ logger(mesh, MESHLINK_INFO, "Node %s discovered on the local network.\n", n->name);
+ }
+
+ switch(sa.sa.sa_family) {
+ case AF_INET:
+ sa.in.sin_port = htons(port);
+ break;
+
+ case AF_INET6:
+ sa.in6.sin6_port = htons(port);
+ break;
+
+ default:
+ logger(mesh, MESHLINK_WARNING, "Could not resolve node %s to a known address family type.\n", n->name);
+ sa.sa.sa_family = AF_UNKNOWN;
+ break;
+ }
+
+ if(sa.sa.sa_family != AF_UNKNOWN) {
+ n->catta_address = sa;
+ n->last_connect_try = 0;
+ node_add_recent_address(mesh, n, &sa);
+
+ if(n->connection) {
+ n->connection->last_ping_time = -3600;
+ }
+
+ for list_each(outgoing_t, outgoing, mesh->outgoings) {
+ if(outgoing->node != n) {
+ continue;
+ }
+
+ outgoing->timeout = 0;
+
+ if(outgoing->ev.cb) {
+ timeout_set(&mesh->loop, &outgoing->ev, &(struct timespec) {
+ 0, 0
+ });
+ }
+ }
+ }
+ }
+ } else if(parse_request(buf, len, mesh->appname, "tcp")) {
+ char *fingerprint = meshlink_get_fingerprint(mesh, (meshlink_node_t *)mesh->self);
+ const char *response_values[] = {mesh->name, fingerprint};
+ size_t size = prepare_response(buf, sizeof(buf), fingerprint, mesh->appname, "tcp", atoi(mesh->myport), 2, keys, response_values);
+
+ int index = -1;
+ int family = AF_UNSPEC;
+
+ for(struct cmsghdr *cmptr = CMSG_FIRSTHDR(&msg); cmptr != NULL; cmptr = CMSG_NXTHDR(&msg, cmptr)) {
+#ifdef IP_PKTINFO
+
+ if(cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_PKTINFO) {
+ struct in_pktinfo *pktinfo = (struct in_pktinfo *) CMSG_DATA(cmptr);
+ index = pktinfo->ipi_ifindex;
+ family = AF_INET;
+ break;
+ } else
+#endif
+#ifdef IPV6_PKTINFO
+ if(cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == IPV6_PKTINFO) {
+ struct in6_pktinfo *pktinfo = (struct in6_pktinfo *) CMSG_DATA(cmptr);
+ index = pktinfo->ipi6_ifindex;
+ family = AF_INET6;
+ break;
+ }
+
+#endif
+ }
+
+ if(index) {
+ // Send a multicast response back using all addresses matching the interface
+ for(int i = 0; i < mesh->discovery.address_count; i++) {
+ discovery_address_t *p = &mesh->discovery.addresses[i];
+
+ if(p->index == index && p->address.sa.sa_family == family) {
+ send_mdns_packet(mesh, p, true);
+ }
+ }
+ } else {
+ // Send a unicast response back
+ sendto(io->fd, buf, size, MSG_DONTWAIT | MSG_NOSIGNAL, &sa.sa, sl);
+ }