fixes #879 Desire NNG_OPT_TCP_BOUND_PORT

We also have made some support changes, including new APIs for printing
URLs, and some improvements to the NNG_OPT_URL to make use of this new
property.

11 files changed, 170 insertions, 75 deletions

diff --git a/docs/man/nng_tcp_options.5.adoc b/docs/man/nng_tcp_options.5.adoc
index f16af5ea..862128ec 100644
--- a/docs/man/nng_tcp_options.5.adoc
+++ b/docs/man/nng_tcp_options.5.adoc
@@ -45,6 +45,18 @@ TCP/IP communications.
 
 === TCP Options
 
+[[NNG_OPT_TCP_BOUND_PORT]]
+((`NNG_OPT_TCP_BOUND_PORT`))::
+(`int`)
+This option is available on listeners, after the listern has bound to
+a port, and provides the port bound to in native byte order.
+This is most useful when using a listener with an ephemeral port
+(configured by using port 0 at configuration time), as it allows
+the caller to determine the actual ephemeral port that was chosen by the
+system.
+While the value is of type `int`, it will be a legal TCP port number, that
+is a value between 1 and 65535, inclusive.
+
 [[NNG_OPT_TCP_NODELAY]]
 ((`NNG_OPT_TCP_NODELAY`))::
 (`bool`)
@@ -94,17 +106,17 @@ middleware from being expiring due to lack of activity.
 Generally, the following option values are also available for TCP objects,
 when appropriate for the context:
 
-* <<nng_options.5#NNG_OPT_LOCADDR,`NNG_OPT_LOCADDR`>>
-* <<nng_options.5#NNG_OPT_REMADDR,`NNG_OPT_REMADDR`>>
+* xref:nng_options.5.adoc#NNG_OPT_LOCADDR[`NNG_OPT_LOCADDR`]
+* xref:nng_options.5.adoc#NNG_OPT_REMADDR[`NNG_OPT_REMADDR`]
 
 == SEE ALSO
 
 [.text-left]
-<<nng_tcp_dialer_getopt.3tcp#,nng_tcp_dialer_getopt(3tcp)>>,
-<<nng_tcp_dialer_setopt.3tcp#,nng_tcp_dialer_setopt(3tcp)>>,
-<<nng_tcp_getopt.3tcp#,nng_tcp_getopt(3tcp)>>,
-<<nng_tcp_listener_getopt.3tcp#,nng_tcp_listener_getopt(3tcp)>>,
-<<nng_tcp_listener_setopt.3tcp#,nng_tcp_listener_setopt(3tcp)>>,
-<<nng_tcp_setopt.3tcp#,nng_tcp_setopt(3tcp)>>,
-<<nng_options.5#,nng_options(5)>>
-<<nng.7#,nng(7)>>
+xref:nng_tcp_dialer_getopt.3tcp.adoc[nng_tcp_dialer_getopt(3tcp)],
+xref:nng_tcp_dialer_setopt.3tcp.adoc[nng_tcp_dialer_setopt(3tcp)],
+xref:nng_tcp_getopt.3tcp.adoc[nng_tcp_getopt(3tcp)],
+xref:nng_tcp_listener_getopt.3tcp.adoc[nng_tcp_listener_getopt(3tcp)],
+xref:nng_tcp_listener_setopt.3tcp.adoc[nng_tcp_listener_setopt(3tcp)],
+xref:nng_tcp_setopt.3tcp.adoc[nng_tcp_setopt(3tcp)],
+xref:nng_options.5.adoc[nng_options(5)]
+xref:nng.7.adoc[nng(7)]
diff --git a/include/nng/nng.h b/include/nng/nng.h
index eb50599a..4c29e476 100644
--- a/include/nng/nng.h
+++ b/include/nng/nng.h
@@ -754,6 +754,14 @@ enum nng_flag_enum {
 // state current). This is a boolean.
 #define NNG_OPT_TCP_KEEPALIVE "tcp-keepalive"
 
+// Local TCP port number.  This is used on a listener, and is intended
+// to be used after starting the listener in combination with a wildcard
+// (0) local port.  This determines the actual ephemeral port that was
+// selected and bound.  The value is provied as an int, but only the
+// low order 16 bits will be set.  This is provided in native byte order,
+// which makes it more convienent than using the NNG_OPT_LOCADDR option.
+#define NNG_OPT_TCP_BOUND_PORT "tcp-bound-port"
+
 // IPC options.  These will largely vary depending on the platform,
 // as POSIX systems have very different options than Windows.
 
@@ -1115,7 +1123,8 @@ NNG_DECL int nng_stream_listener_get_addr(
     nng_stream_listener *, const char *, nng_sockaddr *);
 NNG_DECL int nng_stream_listener_set_bool(
     nng_stream_listener *, const char *, bool);
-NNG_DECL int nng_stream_listener_set_int(nng_stream_listener *, const char *, int);
+NNG_DECL int nng_stream_listener_set_int(
+    nng_stream_listener *, const char *, int);
 NNG_DECL int nng_stream_listener_set_ms(
     nng_stream_listener *, const char *, nng_duration);
 NNG_DECL int nng_stream_listener_set_size(
diff --git a/src/core/url.c b/src/core/url.c
index b2cf77f8..2f1e3a78 100644
--- a/src/core/url.c
+++ b/src/core/url.c
@@ -1,5 +1,5 @@
 //
-// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2019 Staysail Systems, Inc. <info@staysail.tech>
 // Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
@@ -491,6 +491,53 @@ nni_url_free(nni_url *url)
 	}
 }
 
+int
+nni_url_asprintf(char **str, const nni_url *url)
+{
+	const char *scheme = url->u_scheme;
+	const char *port   = url->u_port;
+	const char *host   = url->u_hostname;
+	const char *hostob = "";
+	const char *hostcb = "";
+
+	if ((strcmp(scheme, "ipc") == 0) || (strcmp(scheme, "inproc") == 0)) {
+		return (nni_asprintf(str, "%s://%s", scheme, url->u_path));
+	}
+
+	if (port != NULL) {
+		if ((strlen(port) == 0) ||
+		    (strcmp(nni_url_default_port(scheme), port) == 0)) {
+			port = NULL;
+		}
+	}
+	if (strcmp(host, "*") == 0) {
+		host = "";
+	}
+	if (strchr(host, ':') != 0) {
+		hostob = "[";
+		hostcb = "]";
+	}
+	return (nni_asprintf(str, "%s://%s%s%s%s%s%s", scheme, hostob, host,
+	    hostcb, port != NULL ? ":" : "", port != NULL ? port : "",
+	    url->u_requri != NULL ? url->u_requri : ""));
+}
+
+// nni_url_asprintf_port is like nni_url_asprintf, but includes a port
+// override.  If non-zero, this port number replaces the port number
+// in the port string.
+int
+nni_url_asprintf_port(char **str, const nni_url *url, int port)
+{
+	char    portstr[16];
+	nni_url myurl = *url;
+
+	if (port > 0) {
+		(void) snprintf(portstr, sizeof(portstr), "%d", port);
+		myurl.u_port = portstr;
+	}
+	return (nni_url_asprintf(str, &myurl));
+}
+
 #define URL_COPYSTR(d, s) ((s != NULL) && ((d = nni_strdup(s)) == NULL))
 
 int
diff --git a/src/core/url.h b/src/core/url.h
index 2358f6ba..afb8a882 100644
--- a/src/core/url.h
+++ b/src/core/url.h
@@ -17,5 +17,7 @@ extern int         nni_url_parse(nni_url **, const char *path);
 extern void        nni_url_free(nni_url *);
 extern int         nni_url_clone(nni_url **, const nni_url *);
 extern const char *nni_url_default_port(const char *);
+extern int         nni_url_asprintf(char **, const nni_url *);
+extern int         nni_url_asprintf_port(char **, const nni_url *, int);
 
 #endif // CORE_URL_H
diff --git a/src/platform/windows/win_tcp.h b/src/platform/windows/win_tcp.h
index b37b2353..e54f853c 100644
--- a/src/platform/windows/win_tcp.h
+++ b/src/platform/windows/win_tcp.h
@@ -38,20 +38,6 @@ struct nni_tcp_conn {
 	nni_cv            cv;
 };
 
-struct nni_tcp_listener {
-	SOCKET                    s;
-	nni_list                  aios;
-	bool                      closed;
-	bool                      started;
-	bool                      nodelay;   // initial value for child conns
-	bool                      keepalive; // initial value for child conns
-	LPFN_ACCEPTEX             acceptex;
-	LPFN_GETACCEPTEXSOCKADDRS getacceptexsockaddrs;
-	SOCKADDR_STORAGE          ss;
-	nni_mtx                   mtx;
-	nni_reap_item             reap;
-};
-
-extern int nni_win_tcp_conn_init(nni_tcp_conn **, SOCKET);
+extern int nni_win_tcp_init(nni_tcp_conn **, SOCKET);
 
 #endif // NNG_PLATFORM_WIN_WINTCP_H
diff --git a/src/platform/windows/win_tcpconn.c b/src/platform/windows/win_tcpconn.c
index c77bbc72..429c5a5d 100644
--- a/src/platform/windows/win_tcpconn.c
+++ b/src/platform/windows/win_tcpconn.c
@@ -425,7 +425,7 @@ tcp_free(void *arg)
 }
 
 int
-nni_win_tcp_conn_init(nni_tcp_conn **connp, SOCKET s)
+nni_win_tcp_init(nni_tcp_conn **connp, SOCKET s)
 {
 	nni_tcp_conn *c;
 	int           rv;
diff --git a/src/platform/windows/win_tcpdial.c b/src/platform/windows/win_tcpdial.c
index 6bb3d92a..e295bd8d 100644
--- a/src/platform/windows/win_tcpdial.c
+++ b/src/platform/windows/win_tcpdial.c
@@ -193,7 +193,7 @@ nni_tcp_dial(nni_tcp_dialer *d, nni_aio *aio)
 		return;
 	}
 
-	if ((rv = nni_win_tcp_conn_init(&c, s)) != 0) {
+	if ((rv = nni_win_tcp_init(&c, s)) != 0) {
 		nng_stream_free(&c->ops);
 		nni_aio_finish_error(aio, rv);
 		return;
diff --git a/src/platform/windows/win_tcplisten.c b/src/platform/windows/win_tcplisten.c
index e98a0c37..18e552a6 100644
--- a/src/platform/windows/win_tcplisten.c
+++ b/src/platform/windows/win_tcplisten.c
@@ -17,6 +17,20 @@
 
 #include "win_tcp.h"
 
+struct nni_tcp_listener {
+	SOCKET                    s;
+	nni_list                  aios;
+	bool                      closed;
+	bool                      started;
+	bool                      nodelay;   // initial value for child conns
+	bool                      keepalive; // initial value for child conns
+	LPFN_ACCEPTEX             acceptex;
+	LPFN_GETACCEPTEXSOCKADDRS getacceptexsockaddrs;
+	SOCKADDR_STORAGE          ss;
+	nni_mtx                   mtx;
+	nni_reap_item             reap;
+};
+
 // tcp_listener_funcs looks up function pointers we need for advanced accept
 // functionality on Windows.  Windows is weird.
 static int
@@ -296,7 +310,7 @@ nni_tcp_listener_accept(nni_tcp_listener *l, nni_aio *aio)
 		nni_aio_finish_error(aio, rv);
 		return;
 	}
-	if ((rv = nni_win_tcp_conn_init(&c, s)) != 0) {
+	if ((rv = nni_win_tcp_init(&c, s)) != 0) {
 		nni_mtx_unlock(&l->mtx);
 		closesocket(s);
 		nni_aio_finish_error(aio, rv);
diff --git a/src/supplemental/tcp/tcp.c b/src/supplemental/tcp/tcp.c
index 3ec396b8..21922ef6 100644
--- a/src/supplemental/tcp/tcp.c
+++ b/src/supplemental/tcp/tcp.c
@@ -327,10 +327,51 @@ tcp_listener_accept(void *arg, nng_aio *aio)
 }
 
 static int
+tcp_listener_get_port(void *arg, void *buf, size_t *szp, nni_type t)
+{
+	tcp_listener *l = arg;
+	int           rv;
+	nng_sockaddr  sa;
+	size_t        sz;
+	int           port;
+	uint8_t *     paddr;
+
+	sz = sizeof(sa);
+	rv = nni_tcp_listener_getopt(
+	    l->l, NNG_OPT_LOCADDR, &sa, &sz, NNI_TYPE_SOCKADDR);
+	if (rv != 0) {
+		return (rv);
+	}
+
+	switch (sa.s_family) {
+	case NNG_AF_INET:
+		paddr = (void *) &sa.s_in.sa_port;
+		break;
+
+	case NNG_AF_INET6:
+		paddr = (void *) &sa.s_in.sa_port;
+		break;
+	default:
+		paddr = NULL;
+		break;
+	}
+
+	if (paddr == NULL) {
+		return (NNG_ESTATE);
+	}
+
+	NNI_GET16(paddr, port);
+	return (nni_copyout_int(port, buf, szp, t));
+}
+
+static int
 tcp_listener_getx(
     void *arg, const char *name, void *buf, size_t *szp, nni_type t)
 {
 	tcp_listener *l = arg;
+	if (strcmp(name, NNG_OPT_TCP_BOUND_PORT) == 0) {
+		return (tcp_listener_get_port(l, buf, szp, t));
+	}
 	return (nni_tcp_listener_getopt(l->l, name, buf, szp, t));
 }
 
diff --git a/src/transport/tcp/tcp.c b/src/transport/tcp/tcp.c
index 3d757ee7..f8b1ce54 100644
--- a/src/transport/tcp/tcp.c
+++ b/src/transport/tcp/tcp.c
@@ -57,7 +57,7 @@ struct tcptran_ep {
 	uint16_t             proto;
 	size_t               rcvmax;
 	bool                 fini;
-	nni_url *            url;
+	nng_url *            url;
 	const char *         host; // for dialers
 	nng_sockaddr         src;
 	nni_list             pipes;
@@ -680,7 +680,7 @@ tcptran_ep_close(void *arg)
 // The special handling of this URL format is quite honestly an historical
 // mistake, which we would remove if we could.
 static int
-tcptran_url_parse_source(nni_url *url, nng_sockaddr *sa, const nni_url *surl)
+tcptran_url_parse_source(nng_url *url, nng_sockaddr *sa, const nng_url *surl)
 {
 	int      af;
 	char *   semi;
@@ -736,13 +736,13 @@ tcptran_url_parse_source(nni_url *url, nng_sockaddr *sa, const nni_url *surl)
 }
 
 static int
-tcptran_dialer_init(void **dp, nni_url *url, nni_dialer *ndialer)
+tcptran_dialer_init(void **dp, nng_url *url, nni_dialer *ndialer)
 {
 	tcptran_ep * ep;
 	int          rv;
 	nng_sockaddr srcsa;
 	nni_sock *   sock = nni_dialer_sock(ndialer);
-	nni_url      myurl;
+	nng_url      myurl;
 
 	// Check for invalid URL components.
 	if ((strlen(url->u_path) != 0) && (strcmp(url->u_path, "/") != 0)) {
@@ -783,7 +783,7 @@ tcptran_dialer_init(void **dp, nni_url *url, nni_dialer *ndialer)
 	return (0);
 }
 static int
-tcptran_listener_init(void **lp, nni_url *url, nni_listener *nlistener)
+tcptran_listener_init(void **lp, nng_url *url, nni_listener *nlistener)
 {
 	tcptran_ep *ep;
 	int         rv;
@@ -847,28 +847,20 @@ static int
 tcptran_ep_get_url(void *arg, void *v, size_t *szp, nni_opt_type t)
 {
 	tcptran_ep *ep = arg;
+	char *      s;
+	int         rv;
+	int         port = 0;
 
 	if (ep->listener != NULL) {
-		char         ustr[128];
-		char         ipstr[48];  // max for IPv6 addresses including []
-		char         portstr[6]; // max for 16-bit port
-		nng_sockaddr sa;
-		int          rv;
-		rv = nng_stream_listener_get_addr(
-		    ep->listener, NNG_OPT_LOCADDR, &sa);
-		if (rv != 0) {
-			return (rv);
-		}
-
-		nni_ntop(&sa, ipstr, portstr);
-		snprintf(ustr, sizeof(ustr),
-		    sa.s_family == NNG_AF_INET6 ? "tcp://[%s]:%s"
-		                                : "tcp://%s:%s",
-		    ipstr, portstr);
-		return (nni_copyout_str(ustr, v, szp, t));
+		(void) nng_stream_listener_get_int(
+		    ep->listener, NNG_OPT_TCP_BOUND_PORT, &port);
 	}
 
-	return (nni_copyout_str(ep->url->u_rawurl, v, szp, t));
+	if ((rv = nni_url_asprintf_port(&s, ep->url, port)) == 0) {
+		rv = nni_copyout_str(s, v, szp, t);
+		nni_strfree(s);
+	}
+	return (rv);
 }
 
 static int
diff --git a/src/transport/tls/tls.c b/src/transport/tls/tls.c
index d68cb8b1..8b02702f 100644
--- a/src/transport/tls/tls.c
+++ b/src/transport/tls/tls.c
@@ -907,7 +907,7 @@ tlstran_ep_accept(void *arg, nni_aio *aio)
 }
 
 static int
-tlstran_ep_set_recvmaxsz(void *arg, const void *v, size_t sz, nni_opt_type t)
+tlstran_ep_set_recvmaxsz(void *arg, const void *v, size_t sz, nni_type t)
 {
 	tlstran_ep *ep = arg;
 	size_t      val;
@@ -921,7 +921,7 @@ tlstran_ep_set_recvmaxsz(void *arg, const void *v, size_t sz, nni_opt_type t)
 }
 
 static int
-tlstran_ep_get_recvmaxsz(void *arg, void *v, size_t *szp, nni_opt_type t)
+tlstran_ep_get_recvmaxsz(void *arg, void *v, size_t *szp, nni_type t)
 {
 	tlstran_ep *ep = arg;
 	int         rv;
@@ -932,30 +932,22 @@ tlstran_ep_get_recvmaxsz(void *arg, void *v, size_t *szp, nni_opt_type t)
 }
 
 static int
-tlstran_ep_get_url(void *arg, void *v, size_t *szp, nni_opt_type t)
+tlstran_ep_get_url(void *arg, void *v, size_t *szp, nni_type t)
 {
-	tlstran_ep * ep = arg;
-	char         ustr[128];
-	char         ipstr[48];  // max for IPv6 addresses including []
-	char         portstr[6]; // max for 16-bit port
-	nng_sockaddr sa;
-	size_t       sz = sizeof(sa);
-	int          rv;
+	tlstran_ep *ep = arg;
+	char *      s;
+	int         rv;
+	int         port = 0;
 
-	if (ep->dialer != NULL) {
-		return (nni_copyout_str(ep->url->u_rawurl, v, szp, t));
+	if (ep->listener != NULL) {
+		(void) nng_stream_listener_get_int(
+		    ep->listener, NNG_OPT_TCP_BOUND_PORT, &port);
 	}
-	rv = nni_stream_listener_getx(
-	    ep->listener, NNG_OPT_LOCADDR, &sa, &sz, NNI_TYPE_SOCKADDR);
-	if (rv != 0) {
-		return (rv);
+	if ((rv = nni_url_asprintf_port(&s, ep->url, port)) == 0) {
+		rv = nni_copyout_str(s, v, szp, t);
+		nni_strfree(s);
 	}
-
-	nni_mtx_lock(&ep->mtx);
-	nni_ntop(&sa, ipstr, portstr);
-	nni_mtx_unlock(&ep->mtx);
-	snprintf(ustr, sizeof(ustr), "tls+tcp://%s:%s", ipstr, portstr);
-	return (nni_copyout_str(ustr, v, szp, t));
+	return (rv);
 }
 
 static const nni_option tlstran_pipe_opts[] = {