+/*
+ * Look up a network service in /etc/services and return the
+ * network-order port number of that service.
+ */
+static in_port_t nfs_gp_getservbyname(const char *service,
+ const unsigned short protocol)
+{
+ const struct addrinfo gai_hint = {
+ .ai_family = AF_INET,
+ .ai_protocol = protocol,
+ .ai_flags = AI_PASSIVE,
+ };
+ struct addrinfo *gai_results;
+ const struct sockaddr_in *sin;
+ in_port_t port;
+
+ if (getaddrinfo(NULL, service, &gai_hint, &gai_results) != 0)
+ return 0;
+
+ sin = (const struct sockaddr_in *)gai_results->ai_addr;
+ port = sin->sin_port;
+
+ freeaddrinfo(gai_results);
+ return port;
+}
+
+/*
+ * Discover the port number that should be used to contact an
+ * rpcbind service. This will detect if the port has a local
+ * value that may have been set in /etc/services.
+ *
+ * Returns network byte-order port number of rpcbind service
+ * on this system.
+ */
+static in_port_t nfs_gp_get_rpcb_port(const unsigned short protocol)
+{
+ static const char *rpcb_netnametbl[] = {
+ "rpcbind",
+ "portmapper",
+ "sunrpc",
+ NULL,
+ };
+ unsigned int i;
+
+ for (i = 0; rpcb_netnametbl[i] != NULL; i++) {
+ in_port_t port;
+
+ port = nfs_gp_getservbyname(rpcb_netnametbl[i], protocol);
+ if (port != 0)
+ return port;
+ }
+
+ return (in_port_t)htons((uint16_t)PMAPPORT);
+}
+