fixes #523 dialers could support multiple outstanding dial requests

fixes #179 DNS resolution should be done at connect time
fixes #586 Windows IO completion port work could be better
fixes #339 Windows iocp could use synchronous completions
fixes #280 TCP abstraction improvements

This is a rather monstrous set of changes, which refactors TCP, and
the underlying Windows I/O completion path logic, in order to obtain
a cleaner, simpler API, with support for asynchronous DNS lookups performed
on connect rather than initialization time, the ability to have multiple
connects or accepts pending, as well as fewer extraneous function calls.

The Windows code also benefits from greatly reduced context switching,
fewer lock operations performed, and a reduced number of system calls
on the hot code path.  (We use automatic event resetting instead of manual.)

Some dead code was removed as well, and a few potential edge case leaks
on failure paths (in the websocket code) were plugged.

Note that all TCP based transports benefit from this work. The IPC code
on Windows still uses the legacy IOCP for now, as does the UDP code (used
for ZeroTier.)  We will be converting those soon too.

1 files changed, 37 insertions, 38 deletions

diff --git a/src/supplemental/http/http_server.c b/src/supplemental/http/http_server.c
index 4a07d544..9d1313b1 100644
--- a/src/supplemental/http/http_server.c
+++ b/src/supplemental/http/http_server.c
@@ -64,22 +64,22 @@ typedef struct http_error {
 } http_error;
 
 struct nng_http_server {
-	nng_sockaddr     addr;
-	nni_list_node    node;
-	int              refcnt;
-	int              starts;
-	nni_list         handlers;
-	nni_list         conns;
-	nni_mtx          mtx;
-	nni_cv           cv;
-	bool             closed;
-	nng_tls_config * tls;
-	nni_aio *        accaio;
-	nni_plat_tcp_ep *tep;
-	char *           port;
-	char *           hostname;
-	nni_list         errors;
-	nni_mtx          errors_mtx;
+	nng_sockaddr      addr;
+	nni_list_node     node;
+	int               refcnt;
+	int               starts;
+	nni_list          handlers;
+	nni_list          conns;
+	nni_mtx           mtx;
+	nni_cv            cv;
+	bool              closed;
+	nng_tls_config *  tls;
+	nni_aio *         accaio;
+	nni_tcp_listener *listener;
+	char *            port;
+	char *            hostname;
+	nni_list          errors;
+	nni_mtx           errors_mtx;
 };
 
 int
@@ -682,13 +682,13 @@ http_sconn_cbdone(void *arg)
 }
 
 static int
-http_sconn_init(http_sconn **scp, nni_http_server *s, nni_plat_tcp_pipe *tcp)
+http_sconn_init(http_sconn **scp, nni_http_server *s, nni_tcp_conn *tcp)
 {
 	http_sconn *sc;
 	int         rv;
 
 	if ((sc = NNI_ALLOC_STRUCT(sc)) == NULL) {
-		nni_plat_tcp_pipe_fini(tcp);
+		nni_tcp_conn_fini(tcp);
 		return (NNG_ENOMEM);
 	}
 
@@ -720,17 +720,17 @@ http_sconn_init(http_sconn **scp, nni_http_server *s, nni_plat_tcp_pipe *tcp)
 static void
 http_server_acccb(void *arg)
 {
-	nni_http_server *  s   = arg;
-	nni_aio *          aio = s->accaio;
-	nni_plat_tcp_pipe *tcp;
-	http_sconn *       sc;
-	int                rv;
+	nni_http_server *s   = arg;
+	nni_aio *        aio = s->accaio;
+	nni_tcp_conn *   tcp;
+	http_sconn *     sc;
+	int              rv;
 
 	nni_mtx_lock(&s->mtx);
 	if ((rv = nni_aio_result(aio)) != 0) {
 		if (!s->closed) {
 			// try again?
-			nni_plat_tcp_ep_accept(s->tep, s->accaio);
+			nni_tcp_listener_accept(s->listener, s->accaio);
 		}
 		nni_mtx_unlock(&s->mtx);
 		return;
@@ -738,14 +738,14 @@ http_server_acccb(void *arg)
 	tcp = nni_aio_get_output(aio, 0);
 	if (s->closed) {
 		// If we're closing, then reject this one.
-		nni_plat_tcp_pipe_fini(tcp);
+		nni_tcp_conn_fini(tcp);
 		nni_mtx_unlock(&s->mtx);
 		return;
 	}
 	if (http_sconn_init(&sc, s, tcp) != 0) {
 		// The TCP structure is already cleaned up.
 		// Start another accept attempt.
-		nni_plat_tcp_ep_accept(s->tep, s->accaio);
+		nni_tcp_listener_accept(s->listener, s->accaio);
 		nni_mtx_unlock(&s->mtx);
 		return;
 	}
@@ -753,7 +753,7 @@ http_server_acccb(void *arg)
 	nni_list_append(&s->conns, sc);
 
 	nni_http_read_req(sc->conn, sc->req, sc->rxaio);
-	nni_plat_tcp_ep_accept(s->tep, s->accaio);
+	nni_tcp_listener_accept(s->listener, s->accaio);
 	nni_mtx_unlock(&s->mtx);
 }
 
@@ -769,8 +769,8 @@ http_server_fini(nni_http_server *s)
 	while (!nni_list_empty(&s->conns)) {
 		nni_cv_wait(&s->cv);
 	}
-	if (s->tep != NULL) {
-		nni_plat_tcp_ep_fini(s->tep);
+	if (s->listener != NULL) {
+		nni_tcp_listener_fini(s->listener);
 	}
 	while ((h = nni_list_first(&s->handlers)) != NULL) {
 		nni_list_remove(&s->handlers, h);
@@ -875,7 +875,7 @@ http_server_init(nni_http_server **serverp, const nni_url *url)
 		return (rv);
 	}
 	nni_aio_set_input(aio, 0, &s->addr);
-	nni_plat_tcp_resolv(s->hostname, s->port, NNG_AF_UNSPEC, true, aio);
+	nni_tcp_resolv(s->hostname, s->port, NNG_AF_UNSPEC, true, aio);
 	nni_aio_wait(aio);
 	rv = nni_aio_result(aio);
 	nni_aio_fini(aio);
@@ -921,16 +921,15 @@ static int
 http_server_start(nni_http_server *s)
 {
 	int rv;
-	rv = nni_plat_tcp_ep_init(&s->tep, &s->addr, NULL, NNI_EP_MODE_LISTEN);
-	if (rv != 0) {
+	if ((rv = nni_tcp_listener_init(&s->listener)) != 0) {
 		return (rv);
 	}
-	if ((rv = nni_plat_tcp_ep_listen(s->tep, NULL)) != 0) {
-		nni_plat_tcp_ep_fini(s->tep);
-		s->tep = NULL;
+	if ((rv = nni_tcp_listener_listen(s->listener, &s->addr)) != 0) {
+		nni_tcp_listener_fini(s->listener);
+		s->listener = NULL;
 		return (rv);
 	}
-	nni_plat_tcp_ep_accept(s->tep, s->accaio);
+	nni_tcp_listener_accept(s->listener, s->accaio);
 	return (0);
 }
 
@@ -961,8 +960,8 @@ http_server_stop(nni_http_server *s)
 
 	s->closed = true;
 	// Close the TCP endpoint that is listening.
-	if (s->tep) {
-		nni_plat_tcp_ep_close(s->tep);
+	if (s->listener) {
+		nni_tcp_listener_close(s->listener);
 	}
 
 	// Stopping the server is a hard stop -- it aborts any work