add netmgr functions to support outgoing DNS queries

- isc_nm_tcpdnsconnect() sets up up an outgoing TCP DNS connection
- isc_nm_udpconnect() sets up a connected UDP socket
- isc_nm_read() now supports UDP; it reads a single datagram and then
  stops until the next time it's called.

these functions will later be used to support outgoing queries in dig,
dispatch, etc.

doc/man/dig.1in

@@ -561,11 +561,6 @@ This option displays [or does not display] the TTL in friendly human\-readable t
 units of \fBs\fP, \fBm\fP, \fBh\fP, \fBd\fP, and \fBw\fP, representing seconds, minutes,
 hours, days, and weeks. This implies \fB+ttlid\fP\&.
 .TP
-.B \fB+[no]unexpected\fP
-This option accepts [or does not accept] answers from unexpected sources.  By default, \fBdig\fP
-will not accept a reply from a source other than the one to which it sent the
-query.
-.TP
 .B \fB+[no]unknownformat\fP
 This option prints all RDATA in unknown RR type presentation format (\fI\%RFC 3597\fP).
 The default is to print RDATA for known types in the type\(aqs

lib/isc/include/isc/netmgr.h

@@ -180,6 +180,19 @@ isc_nm_listenudp(isc_nm_t *mgr, isc_nmiface_t *iface, isc_nm_recv_cb_t cb,
  * can then be freed automatically when the handle is destroyed.
  */
 
+isc_result_t
+isc_nm_udpconnect(isc_nm_t *mgr, isc_nmiface_t *local, isc_nmiface_t *peer,
+		  isc_nm_cb_t cb, void *cbarg, size_t extrahandlesize);
+/*%<
+ * Open a UDP socket, bind to 'local' and connect to 'peer', and
+ * immediately call 'cb' with a handle so that the caller can begin
+ * sending packets over UDP.
+ *
+ * When handles are allocated for the socket, 'extrasize' additional bytes
+ * can be allocated along with the handle for an associated object, which
+ * can then be freed automatically when the handle is destroyed.
+ */
+
 void
 isc_nm_stoplistening(isc_nmsocket_t *sock);
 /*%<
@@ -390,3 +403,10 @@ isc_nm_setstats(isc_nm_t *mgr, isc_stats_t *stats);
  *\li	stats is a valid set of statistics counters supporting the
  *	full range of socket-related stats counter numbers.
  */
+
+isc_result_t
+isc_nm_tcpdnsconnect(isc_nm_t *mgr, isc_nmiface_t *local, isc_nmiface_t *peer,
+		     isc_nm_cb_t cb, void *cbarg, size_t extrahandlesize);
+/*%
+ * Establish a DNS client connection over a TCP socket.
+ */

lib/isc/netmgr/netmgr-int.h

@@ -135,8 +135,11 @@ struct isc_nmiface {
 };
 
 typedef enum isc__netievent_type {
+	netievent_udpconnect,
 	netievent_udpsend,
+	netievent_udpread,
 	netievent_udpstop,
+	netievent_udpclose,
 
 	netievent_tcpconnect,
 	netievent_tcpsend,
@@ -148,6 +151,7 @@ typedef enum isc__netievent_type {
 	netievent_tcpclose,
 
 	netievent_tcpdnssend,
+	netievent_tcpdnsread,
 	netievent_tcpdnsclose,
 
 	netievent_closecb,
@@ -210,13 +214,16 @@ typedef struct isc__netievent__socket {
 } isc__netievent__socket_t;
 
 typedef isc__netievent__socket_t isc__netievent_udplisten_t;
+typedef isc__netievent__socket_t isc__netievent_udpread_t;
 typedef isc__netievent__socket_t isc__netievent_udpstop_t;
+typedef isc__netievent__socket_t isc__netievent_udpclose_t;
 typedef isc__netievent__socket_t isc__netievent_tcpstop_t;
 typedef isc__netievent__socket_t isc__netievent_tcpclose_t;
 typedef isc__netievent__socket_t isc__netievent_startread_t;
 typedef isc__netievent__socket_t isc__netievent_pauseread_t;
 typedef isc__netievent__socket_t isc__netievent_closecb_t;
 typedef isc__netievent__socket_t isc__netievent_tcpdnsclose_t;
+typedef isc__netievent__socket_t isc__netievent_tcpdnsread_t;
 
 typedef struct isc__netievent__socket_req {
 	isc__netievent_type type;
@@ -260,6 +267,12 @@ typedef struct isc__netievent_udpsend {
 	isc__nm_uvreq_t *req;
 } isc__netievent_udpsend_t;
 
+typedef struct isc__netievent_udpconnect {
+	isc__netievent_type type;
+	isc_nmsocket_t *sock;
+	isc_sockaddr_t peer;
+} isc__netievent_udpconnect_t;
+
 typedef struct isc__netievent {
 	isc__netievent_type type;
 } isc__netievent_t;
@@ -546,6 +559,9 @@ struct isc_nmsocket {
 	isc_nm_recv_cb_t recv_cb;
 	void *recv_cbarg;
 
+	isc_nm_cb_t connect_cb;
+	void *connect_cbarg;
+
 	isc_nm_accept_cb_t accept_cb;
 	void *accept_cbarg;
 #ifdef NETMGR_TRACE
@@ -681,16 +697,34 @@ isc__nm_udp_send(isc_nmhandle_t *handle, isc_region_t *region, isc_nm_cb_t cb,
  * Back-end implementation of isc_nm_send() for UDP handles.
  */
 
+isc_result_t
+isc__nm_udp_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg);
+/*
+ * Back-end implementation of isc_nm_read() for UDP handles.
+ */
+
+void
+isc__nm_udp_close(isc_nmsocket_t *sock);
+/*%<
+ * Close a UDP socket.
+ */
+
 void
 isc__nm_udp_stoplistening(isc_nmsocket_t *sock);
 
 void
 isc__nm_async_udplisten(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_udpconnect(isc__networker_t *worker, isc__netievent_t *ev0);
 
 void
 isc__nm_async_udpstop(isc__networker_t *worker, isc__netievent_t *ev0);
 void
 isc__nm_async_udpsend(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_udpread(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_udpclose(isc__networker_t *worker, isc__netievent_t *ev0);
 /*%<
  * Callback handlers for asynchronous UDP events (listen, stoplisten, send).
  */
@@ -791,6 +825,18 @@ isc__nm_async_tcpdnsclose(isc__networker_t *worker, isc__netievent_t *ev0);
 void
 isc__nm_async_tcpdnssend(isc__networker_t *worker, isc__netievent_t *ev0);
 
+void
+isc__nm_async_tcpdnsread(isc__networker_t *worker, isc__netievent_t *ev0);
+
+isc_result_t
+isc__nm_tcpdns_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg);
+
+void
+isc__nm_tcpdns_cancelread(isc_nmhandle_t *handle);
+/*%<
+ * Stop reading on a connected TCPDNS handle.
+ */
+
 #define isc__nm_uverr2result(x) \
 	isc___nm_uverr2result(x, true, __FILE__, __LINE__)
 isc_result_t

lib/isc/netmgr/netmgr.c

@@ -604,6 +604,9 @@ process_queue(isc__networker_t *worker, isc_queue_t *queue) {
 			more = false;
 			break;
 
+		case netievent_udpconnect:
+			isc__nm_async_udpconnect(worker, ievent);
+			break;
 		case netievent_udplisten:
 			isc__nm_async_udplisten(worker, ievent);
 			break;
@@ -613,6 +616,12 @@ process_queue(isc__networker_t *worker, isc_queue_t *queue) {
 		case netievent_udpsend:
 			isc__nm_async_udpsend(worker, ievent);
 			break;
+		case netievent_udpread:
+			isc__nm_async_udpread(worker, ievent);
+			break;
+		case netievent_udpclose:
+			isc__nm_async_udpclose(worker, ievent);
+			break;
 
 		case netievent_tcpconnect:
 			isc__nm_async_tcpconnect(worker, ievent);
@@ -648,6 +657,9 @@ process_queue(isc__networker_t *worker, isc_queue_t *queue) {
 		case netievent_tcpdnsclose:
 			isc__nm_async_tcpdnsclose(worker, ievent);
 			break;
+		case netievent_tcpdnsread:
+			isc__nm_async_tcpdnsread(worker, ievent);
+			break;
 
 		case netievent_closecb:
 			isc__nm_async_closecb(worker, ievent);
@@ -907,6 +919,9 @@ isc__nmsocket_prep_destroy(isc_nmsocket_t *sock) {
 	 */
 	if (!atomic_load(&sock->closed)) {
 		switch (sock->type) {
+		case isc_nm_udpsocket:
+			isc__nm_udp_close(sock);
+			return;
 		case isc_nm_tcpsocket:
 			isc__nm_tcp_close(sock);
 			return;
@@ -1416,8 +1431,12 @@ isc_nm_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
 	REQUIRE(VALID_NMHANDLE(handle));
 
 	switch (handle->sock->type) {
+	case isc_nm_udpsocket:
+		return (isc__nm_udp_read(handle, cb, cbarg));
 	case isc_nm_tcpsocket:
 		return (isc__nm_tcp_read(handle, cb, cbarg));
+	case isc_nm_tcpdnssocket:
+		return (isc__nm_tcpdns_read(handle, cb, cbarg));
 	default:
 		INSIST(0);
 		ISC_UNREACHABLE();
@@ -1432,6 +1451,9 @@ isc_nm_cancelread(isc_nmhandle_t *handle) {
 	case isc_nm_tcpsocket:
 		isc__nm_tcp_cancelread(handle);
 		break;
+	case isc_nm_tcpdnssocket:
+		isc__nm_tcpdns_cancelread(handle);
+		break;
 	default:
 		INSIST(0);
 		ISC_UNREACHABLE();

lib/isc/netmgr/tcp.c

@@ -160,6 +160,7 @@ tcp_connect_cb(uv_connect_t *uvreq, int status) {
 	if (status != 0) {
 		req->cb.connect(NULL, isc__nm_uverr2result(status), req->cbarg);
 		isc__nm_uvreq_put(&req, sock);
+		isc__nmsocket_detach(&sock);
 		return;
 	}
 
@@ -262,8 +263,11 @@ isc_nm_listentcp(isc_nm_t *mgr, isc_nmiface_t *iface,
 
 	nsock = isc_mem_get(mgr->mctx, sizeof(*nsock));
 	isc__nmsocket_init(nsock, mgr, isc_nm_tcplistener, iface);
+
+	LOCK(&nsock->lock);
 	nsock->accept_cb = accept_cb;
 	nsock->accept_cbarg = accept_cbarg;
+	UNLOCK(&nsock->lock);
 	nsock->extrahandlesize = extrahandlesize;
 	nsock->backlog = backlog;
 	nsock->result = ISC_R_SUCCESS;

lib/isc/netmgr/tcpdns.c

@@ -270,6 +270,10 @@ dnslisten_readcb(isc_nmhandle_t *handle, isc_result_t eresult,
 	if (region == NULL || eresult != ISC_R_SUCCESS) {
 		/* Connection closed */
 		dnssock->result = eresult;
+		if (atomic_load(&dnssock->client) && dnssock->recv_cb != NULL) {
+			dnssock->recv_cb(dnssock->statichandle, eresult, NULL,
+					 dnssock->recv_cbarg);
+		}
 		if (dnssock->self != NULL) {
 			isc__nmsocket_detach(&dnssock->self);
 		}
@@ -277,7 +281,15 @@ dnslisten_readcb(isc_nmhandle_t *handle, isc_result_t eresult,
 		if (dnssock->outerhandle != NULL) {
 			isc_nmhandle_detach(&dnssock->outerhandle);
 		}
-		isc_nmhandle_detach(&handle);
+
+		/*
+		 * Server connections will hold two handle references when
+		 * shut down, but client (tcpdnsconnect) connections have
+		 * only one.
+		 */
+		if (!atomic_load(&dnssock->client)) {
+			isc_nmhandle_detach(&handle);
+		}
 		return;
 	}
 
@@ -673,3 +685,172 @@ isc__nm_async_tcpdnsclose(isc__networker_t *worker, isc__netievent_t *ev0) {
 
 	tcpdns_close_direct(ievent->sock);
 }
+
+typedef struct {
+	isc_mem_t *mctx;
+	isc_nm_cb_t cb;
+	void *cbarg;
+	size_t extrahandlesize;
+} tcpconnect_t;
+
+static void
+tcpdnsconnect_cb(isc_nmhandle_t *handle, isc_result_t result, void *arg) {
+	tcpconnect_t *conn = (tcpconnect_t *)arg;
+	isc_nm_cb_t cb = conn->cb;
+	void *cbarg = conn->cbarg;
+	size_t extrahandlesize = conn->extrahandlesize;
+	isc_nmsocket_t *dnssock = NULL;
+
+	REQUIRE(result != ISC_R_SUCCESS || VALID_NMHANDLE(handle));
+
+	isc_mem_putanddetach(&conn->mctx, conn, sizeof(*conn));
+
+	if (result != ISC_R_SUCCESS) {
+		cb(NULL, result, cbarg);
+		return;
+	}
+
+	dnssock = isc_mem_get(handle->sock->mgr->mctx, sizeof(*dnssock));
+	isc__nmsocket_init(dnssock, handle->sock->mgr, isc_nm_tcpdnssocket,
+			   handle->sock->iface);
+
+	dnssock->extrahandlesize = extrahandlesize;
+	isc_nmhandle_attach(handle, &dnssock->outerhandle);
+
+	dnssock->peer = handle->sock->peer;
+	dnssock->read_timeout = handle->sock->mgr->init;
+	dnssock->tid = isc_nm_tid();
+
+	atomic_init(&dnssock->client, true);
+	dnssock->statichandle = isc__nmhandle_get(dnssock, NULL, NULL);
+
+	uv_timer_init(&dnssock->mgr->workers[isc_nm_tid()].loop,
+		      &dnssock->timer);
+	dnssock->timer.data = dnssock;
+	dnssock->timer_initialized = true;
+	uv_timer_start(&dnssock->timer, dnstcp_readtimeout,
+		       dnssock->read_timeout, 0);
+
+	/*
+	 * The connection is now established; we start reading immediately,
+	 * before we've been asked to. We'll read and buffer at most one
+	 * packet.
+	 */
+	result = isc_nm_read(handle, dnslisten_readcb, dnssock);
+	cb(dnssock->statichandle, result, cbarg);
+	isc__nmsocket_detach(&dnssock);
+}
+
+isc_result_t
+isc_nm_tcpdnsconnect(isc_nm_t *mgr, isc_nmiface_t *local, isc_nmiface_t *peer,
+		     isc_nm_cb_t cb, void *cbarg, size_t extrahandlesize) {
+	tcpconnect_t *conn = isc_mem_get(mgr->mctx, sizeof(tcpconnect_t));
+
+	*conn = (tcpconnect_t){ .cb = cb,
+				.cbarg = cbarg,
+				.extrahandlesize = extrahandlesize };
+	isc_mem_attach(mgr->mctx, &conn->mctx);
+	return (isc_nm_tcpconnect(mgr, local, peer, tcpdnsconnect_cb, conn, 0));
+}
+
+isc_result_t
+isc__nm_tcpdns_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
+	isc_nmsocket_t *sock = handle->sock;
+	isc__netievent_tcpdnsread_t *ievent = NULL;
+	isc_nmhandle_t *eventhandle = NULL;
+
+	REQUIRE(handle == sock->statichandle);
+	REQUIRE(sock->recv_cb == NULL);
+	REQUIRE(atomic_load(&sock->client));
+
+	/*
+	 * This MUST be done asynchronously, no matter which thread we're
+	 * in. The callback function for isc_nm_read() often calls
+	 * isc_nm_read() again; if we tried to do that synchronously
+	 * we'd clash in processbuffer() and grow the stack indefinitely.
+	 */
+	ievent = isc__nm_get_ievent(sock->mgr, netievent_tcpdnsread);
+	ievent->sock = sock;
+
+	LOCK(&sock->lock);
+	sock->recv_cb = cb;
+	sock->recv_cbarg = cbarg;
+	UNLOCK(&sock->lock);
+
+	/*
+	 * Add a reference to the handle to keep it from being freed by
+	 * the caller; it will be detached in in isc__nm_async_tcpdnsread().
+	 */
+	isc_nmhandle_attach(handle, &eventhandle);
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+	return (ISC_R_SUCCESS);
+}
+
+void
+isc__nm_async_tcpdnsread(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc_result_t result;
+	isc__netievent_tcpdnsread_t *ievent =
+		(isc__netievent_tcpdnsclose_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc_nmhandle_t *handle = NULL, *newhandle = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(worker->id == sock->tid);
+
+	handle = sock->statichandle;
+
+	if (sock->type != isc_nm_tcpdnssocket || sock->outerhandle == NULL) {
+		if (sock->recv_cb != NULL) {
+			sock->recv_cb(handle, ISC_R_NOTCONNECTED, NULL,
+				      sock->recv_cbarg);
+		}
+		isc_nmhandle_detach(&handle);
+		return;
+	}
+
+	/*
+	 * Maybe we have a packet already?
+	 */
+	result = processbuffer(sock, &newhandle);
+	if (result == ISC_R_SUCCESS) {
+		atomic_store(&sock->outerhandle->sock->processing, true);
+		if (sock->timer_initialized) {
+			uv_timer_stop(&sock->timer);
+		}
+		isc_nmhandle_detach(&newhandle);
+	} else if (sock->outerhandle != NULL) {
+		/* Restart reading, wait for the callback */
+		atomic_store(&sock->outerhandle->sock->processing, false);
+		if (sock->timer_initialized) {
+			uv_timer_start(&sock->timer, dnstcp_readtimeout,
+				       sock->read_timeout, 0);
+		}
+		isc_nm_resumeread(sock->outerhandle);
+	} else {
+		isc_nm_recv_cb_t cb = sock->recv_cb;
+		void *cbarg = sock->recv_cbarg;
+
+		isc__nmsocket_clearcb(sock);
+		cb(handle, ISC_R_NOTCONNECTED, NULL, cbarg);
+	}
+
+	isc_nmhandle_detach(&handle);
+}
+
+void
+isc__nm_tcpdns_cancelread(isc_nmhandle_t *handle) {
+	isc_nmsocket_t *sock = NULL;
+
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	sock = handle->sock;
+
+	REQUIRE(sock->type == isc_nm_tcpdnssocket);
+
+	if (atomic_load(&sock->client) && sock->recv_cb != NULL) {
+		sock->recv_cb(handle, ISC_R_EOF, NULL, sock->recv_cbarg);
+		isc__nmsocket_clearcb(sock);
+		isc__nm_tcp_cancelread(sock->outerhandle);
+	}
+}

lib/isc/netmgr/udp.c

@@ -40,6 +40,9 @@ udp_recv_cb(uv_udp_t *handle, ssize_t nrecv, const uv_buf_t *buf,
 static void
 udp_send_cb(uv_udp_send_t *req, int status);
 
+static void
+udp_close_cb(uv_handle_t *uvhandle);
+
 isc_result_t
 isc_nm_listenudp(isc_nm_t *mgr, isc_nmiface_t *iface, isc_nm_recv_cb_t cb,
 		 void *cbarg, size_t extrahandlesize, isc_nmsocket_t **sockp) {
@@ -59,9 +62,11 @@ isc_nm_listenudp(isc_nm_t *mgr, isc_nmiface_t *iface, isc_nm_recv_cb_t cb,
 				      mgr->nworkers * sizeof(*nsock));
 	memset(nsock->children, 0, mgr->nworkers * sizeof(*nsock));
 
+	LOCK(&nsock->lock);
 	INSIST(nsock->recv_cb == NULL && nsock->recv_cbarg == NULL);
 	nsock->recv_cb = cb;
 	nsock->recv_cbarg = cbarg;
+	UNLOCK(&nsock->lock);
 	nsock->extrahandlesize = extrahandlesize;
 
 	for (size_t i = 0; i < mgr->nworkers; i++) {
@@ -76,9 +81,11 @@ isc_nm_listenudp(isc_nm_t *mgr, isc_nmiface_t *iface, isc_nm_recv_cb_t cb,
 		csock->tid = i;
 		csock->extrahandlesize = extrahandlesize;
 
+		LOCK(&csock->lock);
 		INSIST(csock->recv_cb == NULL && csock->recv_cbarg == NULL);
 		csock->recv_cb = cb;
 		csock->recv_cbarg = cbarg;
+		UNLOCK(&csock->lock);
 		csock->fd = socket(sa_family, SOCK_DGRAM, 0);
 		RUNTIME_CHECK(csock->fd >= 0);
 
@@ -375,19 +382,19 @@ udp_recv_cb(uv_udp_t *handle, ssize_t nrecv, const uv_buf_t *buf,
 
 	result = isc_sockaddr_fromsockaddr(&sockaddr, addr);
 	RUNTIME_CHECK(result == ISC_R_SUCCESS);
-	nmhandle = isc__nmhandle_get(sock, &sockaddr, NULL);
+	if (!atomic_load(&sock->connected)) {
+		nmhandle = isc__nmhandle_get(sock, &sockaddr, NULL);
+	} else {
+		nmhandle = sock->statichandle;
+	}
 	region.base = (unsigned char *)buf->base;
 	region.length = nrecv;
 
-	/*
-	 * In tcp.c and tcpdns.c, this would need to be locked
-	 * by sock->lock because callbacks may be set to NULL
-	 * unexpectedly when the connection drops, but that isn't
-	 * a factor in the UDP case.
-	 */
+	LOCK(&sock->lock);
 	INSIST(sock->recv_cb != NULL);
 	cb = sock->recv_cb;
 	cbarg = sock->recv_cbarg;
+	UNLOCK(&sock->lock);
 
 	cb(nmhandle, ISC_R_SUCCESS, &region, cbarg);
 
@@ -562,3 +569,271 @@ udp_send_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
 
 	return (ISC_R_SUCCESS);
 }
+
+/*
+ * Asynchronous 'udpconnect' call handler: open a new UDP socket and call
+ * the 'open' callback with a handle.
+ */
+void
+isc__nm_async_udpconnect(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_udpconnect_t *ievent =
+		(isc__netievent_udpconnect_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc_nmhandle_t *handle = NULL;
+	isc_nm_cb_t cb;
+	void *cbarg;
+	int uv_bind_flags = UV_UDP_REUSEADDR;
+	int r;
+
+	REQUIRE(sock->type == isc_nm_udpsocket);
+	REQUIRE(sock->iface != NULL);
+	REQUIRE(sock->parent == NULL);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	uv_udp_init(&worker->loop, &sock->uv_handle.udp);
+	uv_handle_set_data(&sock->uv_handle.handle, NULL);
+	uv_handle_set_data(&sock->uv_handle.handle, sock);
+	handle = isc__nmhandle_get(sock, &ievent->peer, &sock->iface->addr);
+
+	r = uv_udp_open(&sock->uv_handle.udp, sock->fd);
+	if (r != 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPENFAIL]);
+		atomic_store(&sock->closed, true);
+		atomic_store(&sock->connect_error, true);
+		sock->result = isc__nm_uverr2result(r);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPEN]);
+
+	if (sock->iface->addr.type.sa.sa_family == AF_INET6) {
+		uv_bind_flags |= UV_UDP_IPV6ONLY;
+	}
+
+	r = uv_udp_bind(&sock->uv_handle.udp, &sock->iface->addr.type.sa,
+			uv_bind_flags);
+	if (r != 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_BINDFAIL]);
+		atomic_store(&sock->connect_error, true);
+		sock->result = isc__nm_uverr2result(r);
+		goto done;
+	}
+
+	r = uv_udp_connect(&sock->uv_handle.udp, &ievent->peer.type.sa);
+	if (r != 0) {
+		isc__nm_incstats(sock->mgr,
+				 sock->statsindex[STATID_CONNECTFAIL]);
+		atomic_store(&sock->connect_error, true);
+		sock->result = isc__nm_uverr2result(r);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CONNECT]);
+
+#ifdef ISC_RECV_BUFFER_SIZE
+	uv_recv_buffer_size(&sock->uv_handle.handle,
+			    &(int){ ISC_RECV_BUFFER_SIZE });
+#endif
+#ifdef ISC_SEND_BUFFER_SIZE
+	uv_send_buffer_size(&sock->uv_handle.handle,
+			    &(int){ ISC_SEND_BUFFER_SIZE });
+#endif
+
+	atomic_store(&sock->connected, true);
+	sock->result = ISC_R_SUCCESS;
+
+done:
+	LOCK(&sock->lock);
+	cb = sock->connect_cb;
+	cbarg = sock->connect_cbarg;
+	UNLOCK(&sock->lock);
+
+	cb(handle, sock->result, cbarg);
+
+	LOCK(&sock->lock);
+	SIGNAL(&sock->cond);
+	UNLOCK(&sock->lock);
+
+	isc__nmsocket_detach(&sock);
+}
+
+isc_result_t
+isc_nm_udpconnect(isc_nm_t *mgr, isc_nmiface_t *local, isc_nmiface_t *peer,
+		  isc_nm_cb_t cb, void *cbarg, size_t extrahandlesize) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc_nmsocket_t *sock = NULL, *tmp = NULL;
+	isc__netievent_udpconnect_t *event = NULL;
+	int r = 0;
+
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(local != NULL);
+	REQUIRE(peer != NULL);
+
+	sock = isc_mem_get(mgr->mctx, sizeof(isc_nmsocket_t));
+	isc__nmsocket_init(sock, mgr, isc_nm_udpsocket, local);
+
+	LOCK(&sock->lock);
+	INSIST(sock->connect_cb == NULL && sock->connect_cbarg == NULL);
+	sock->connect_cb = cb;
+	sock->connect_cbarg = cbarg;
+	UNLOCK(&sock->lock);
+	sock->extrahandlesize = extrahandlesize;
+	sock->peer = peer->addr;
+	atomic_init(&sock->client, true);
+
+	sock->fd = socket(peer->addr.type.sa.sa_family, SOCK_DGRAM, 0);
+	RUNTIME_CHECK(sock->fd >= 0);
+
+	/*
+	 * Set up SO_REUSE* (see comments in isc_nm_listenudp() for
+	 * details).
+	 */
+#if defined(SO_REUSEADDR)
+	r = setsockopt(sock->fd, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 },
+		       sizeof(int));
+	RUNTIME_CHECK(r == 0);
+#endif
+#if defined(SO_REUSEPORT_LB)
+	r = setsockopt(sock->fd, SOL_SOCKET, SO_REUSEPORT_LB, &(int){ 1 },
+		       sizeof(int));
+	RUNTIME_CHECK(r == 0);
+#elif defined(SO_REUSEPORT)
+	r = setsockopt(sock->fd, SOL_SOCKET, SO_REUSEPORT, &(int){ 1 },
+		       sizeof(int));
+	RUNTIME_CHECK(r == 0);
+#endif
+
+#ifdef SO_INCOMING_CPU
+	(void)setsockopt(sock->fd, SOL_SOCKET, SO_INCOMING_CPU, &(int){ 1 },
+			 sizeof(int));
+#endif
+
+	event = isc__nm_get_ievent(mgr, netievent_udpconnect);
+	event->sock = sock;
+	event->peer = *((isc_sockaddr_t *)peer);
+
+	/*
+	 * Hold an additional sock reference so async callbacks
+	 * can't destroy it until we're ready.
+	 */
+	isc__nmsocket_attach(sock, &tmp);
+
+	r = isc_random_uniform(mgr->nworkers);
+	if (r == isc_nm_tid()) {
+		isc__nm_async_udpconnect(&mgr->workers[r],
+					 (isc__netievent_t *)event);
+		isc__nm_put_ievent(mgr, event);
+	} else {
+		isc__nm_enqueue_ievent(&mgr->workers[r],
+				       (isc__netievent_t *)event);
+
+		LOCK(&sock->lock);
+		while (!atomic_load(&sock->connected) &&
+		       !atomic_load(&sock->connect_error)) {
+			WAIT(&sock->cond, &sock->lock);
+		}
+		UNLOCK(&sock->lock);
+	}
+
+	if (sock->result != ISC_R_SUCCESS) {
+		result = sock->result;
+		isc__nmsocket_detach(&sock);
+	}
+
+	isc__nmsocket_detach(&tmp);
+
+	return (result);
+}
+
+static void
+udp_read_cb(uv_udp_t *handle, ssize_t nrecv, const uv_buf_t *buf,
+	    const struct sockaddr *addr, unsigned flags) {
+	isc_nmsocket_t *sock = uv_handle_get_data((uv_handle_t *)handle);
+
+	udp_recv_cb(handle, nrecv, buf, addr, flags);
+	uv_udp_recv_stop(&sock->uv_handle.udp);
+}
+
+/*
+ * Asynchronous 'udpread' call handler: start or resume reading on a socket;
+ * pause reading and call the 'recv' callback after each datagram.
+ */
+void
+isc__nm_async_udpread(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_udpread_t *ievent = (isc__netievent_udpread_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	UNUSED(worker);
+
+	uv_udp_recv_start(&sock->uv_handle.udp, udp_alloc_cb, udp_read_cb);
+}
+
+isc_result_t
+isc__nm_udp_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
+	isc_nmsocket_t *sock = NULL;
+	isc__netievent_startread_t *ievent = NULL;
+
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+	REQUIRE(handle->sock->type == isc_nm_udpsocket);
+
+	sock = handle->sock;
+
+	LOCK(&sock->lock);
+	sock->recv_cb = cb;
+	sock->recv_cbarg = cbarg;
+	UNLOCK(&sock->lock);
+
+	ievent = isc__nm_get_ievent(sock->mgr, netievent_udpread);
+	ievent->sock = sock;
+
+	if (sock->tid == isc_nm_tid()) {
+		isc__nm_async_udpread(&sock->mgr->workers[sock->tid],
+				      (isc__netievent_t *)ievent);
+		isc__nm_put_ievent(sock->mgr, ievent);
+	} else {
+		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+static void
+udp_close_cb(uv_handle_t *uvhandle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(uvhandle);
+
+	REQUIRE(VALID_NMSOCK(sock));
+
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CLOSE]);
+	atomic_store(&sock->closed, true);
+	isc__nmsocket_prep_destroy(sock);
+}
+
+void
+isc__nm_async_udpclose(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_udpclose_t *ievent = (isc__netievent_udpclose_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	REQUIRE(worker->id == ievent->sock->tid);
+
+	uv_close(&sock->uv_handle.handle, udp_close_cb);
+}
+
+void
+isc__nm_udp_close(isc_nmsocket_t *sock) {
+	isc__netievent_udpclose_t *ievent = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_udpsocket);
+
+	ievent = isc__nm_get_ievent(sock->mgr, netievent_udpclose);
+	ievent->sock = sock;
+
+	if (sock->tid == isc_nm_tid()) {
+		isc__nm_async_udpclose(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+		isc__nm_put_ievent(sock->mgr, ievent);
+	} else {
+		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+}

lib/isc/win32/libisc.def.in

@@ -461,11 +461,13 @@ isc_nm_setstats
 isc_nm_start
 isc_nm_stoplistening
 isc_nm_tcpconnect
+isc_nm_tcpdnsconnect
 isc_nm_tcp_gettimeouts
 isc_nm_tcp_settimeouts
 isc_nm_tcpdns_keepalive
 isc_nm_tcpdns_sequential
 isc_nm_tid
+isc_nm_udpconnect
 isc_nmsocket_close
 isc__nm_acquire_interlocked
 isc__nm_drop_interlocked