+#ifdef IPV6_SUPPORTED
+static int smn_socket(void)
+{
+ int sock;
+
+ /*
+ * Use an AF_INET socket if IPv6 is disabled on the
+ * local system.
+ */
+ sock = socket(AF_INET6, SOCK_DGRAM, 0);
+ if (sock == -1) {
+ if (errno != EAFNOSUPPORT) {
+ xlog(L_ERROR, "Failed to create RPC socket: %m");
+ return -1;
+ }
+ sock = socket(AF_INET, SOCK_DGRAM, 0);
+ if (sock < 0) {
+ xlog(L_ERROR, "Failed to create RPC socket: %m");
+ return -1;
+ }
+ } else
+ nsm_family = AF_INET6;
+
+ if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1) {
+ xlog(L_ERROR, "fcntl(3) on RPC socket failed: %m");
+ goto out_close;
+ }
+
+ /*
+ * TI-RPC over IPv6 (udp6/tcp6) does not handle IPv4. However,
+ * since sm-notify open-codes all of its RPC support, it can
+ * use a single socket and let the local network stack provide
+ * the correct mapping between address families automatically.
+ * This is the same thing that is done in the kernel.
+ */
+ if (nsm_family == AF_INET6) {
+ const int zero = 0;
+ socklen_t zerolen = (socklen_t)sizeof(zero);
+
+ if (setsockopt(sock, SOL_IPV6, IPV6_V6ONLY,
+ (char *)&zero, zerolen) == -1) {
+ xlog(L_ERROR, "setsockopt(3) on RPC socket failed: %m");
+ goto out_close;
+ }
+ }
+
+ return sock;
+
+out_close:
+ (void)close(sock);
+ return -1;
+}
+#else /* !IPV6_SUPPORTED */
+static int smn_socket(void)
+{
+ int sock;
+
+ sock = socket(AF_INET, SOCK_DGRAM, 0);
+ if (sock == -1) {
+ xlog(L_ERROR, "Failed to create RPC socket: %m");
+ return -1;
+ }
+
+ if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1) {
+ xlog(L_ERROR, "fcntl(3) on RPC socket failed: %m");
+ (void)close(sock);
+ return -1;
+ }
+
+ return sock;
+}
+#endif /* !IPV6_SUPPORTED */
+
+/*
+ * If admin specified a source address or srcport, then convert those
+ * to a sockaddr and return it. Otherwise, return an ANYADDR address.
+ */
+__attribute_malloc__
+static struct addrinfo *
+smn_bind_address(const char *srcaddr, const char *srcport)
+{
+ struct addrinfo *ai = NULL;
+ struct addrinfo hint = {
+ .ai_flags = AI_NUMERICSERV,
+ .ai_family = nsm_family,
+ .ai_protocol = (int)IPPROTO_UDP,
+ };
+ int error;
+
+ if (srcaddr == NULL)
+ hint.ai_flags |= AI_PASSIVE;
+
+ /* Do not allow "node" and "service" parameters both to be NULL */
+ if (srcport == NULL)
+ error = getaddrinfo(srcaddr, "", &hint, &ai);
+ else
+ error = getaddrinfo(srcaddr, srcport, &hint, &ai);
+ if (error != 0) {
+ xlog(L_ERROR,
+ "Invalid bind address or port for RPC socket: %s",
+ gai_strerror(error));
+ return NULL;
+ }
+
+ return ai;
+}
+
+#ifdef HAVE_LIBTIRPC
+static int
+smn_bindresvport(int sock, struct sockaddr *sap)
+{
+ return bindresvport_sa(sock, sap);
+}
+
+#else /* !HAVE_LIBTIRPC */
+static int
+smn_bindresvport(int sock, struct sockaddr *sap)
+{
+ if (sap->sa_family != AF_INET) {
+ errno = EAFNOSUPPORT;
+ return -1;
+ }
+
+ return bindresvport(sock, (struct sockaddr_in *)(char *)sap);
+}
+#endif /* !HAVE_LIBTIRPC */
+
+/*
+ * Prepare a socket for sending RPC requests
+ *
+ * Returns a bound datagram socket file descriptor, or -1 if
+ * an error occurs.
+ */
+static int
+smn_create_socket(const char *srcaddr, const char *srcport)
+{
+ int sock, retry_cnt = 0;
+ struct addrinfo *ai;
+
+retry:
+ sock = smn_socket();
+ if (sock == -1)
+ return -1;
+
+ ai = smn_bind_address(srcaddr, srcport);
+ if (ai == NULL) {
+ (void)close(sock);
+ return -1;
+ }
+
+ /* Use source port if provided on the command line,
+ * otherwise use bindresvport */
+ if (srcport) {
+ if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) {
+ xlog(L_ERROR, "Failed to bind RPC socket: %m");
+ freeaddrinfo(ai);
+ (void)close(sock);
+ return -1;
+ }
+ } else {
+ struct servent *se;
+
+ if (smn_bindresvport(sock, ai->ai_addr) == -1) {
+ xlog(L_ERROR,
+ "bindresvport on RPC socket failed: %m");
+ freeaddrinfo(ai);
+ (void)close(sock);
+ return -1;
+ }
+
+ /* try to avoid known ports */
+ se = getservbyport((int)nfs_get_port(ai->ai_addr), "udp");
+ if (se != NULL && retry_cnt < 100) {
+ retry_cnt++;
+ freeaddrinfo(ai);
+ (void)close(sock);
+ goto retry;
+ }
+ }
+
+ freeaddrinfo(ai);
+ return sock;
+}
+