Merge branch '3200-add-per-send-timer' into 'main'

Change single write timer to per-send timers

Closes #3200

See merge request isc-projects/bind9!5955

CHANGES

@@ -1,3 +1,6 @@
+5828.	[bug]		Replace single TCP write timer with per-TCP write
+			timers. [GL #3200]
+
 5827.	[cleanup]	The command-line utilities printed their version numbers
 			inconsistently; they all now print to stdout. (They are
 			still inconsistent abotut whether you use `-v` or `-V`
@@ -6,7 +9,7 @@
 5826.	[cleanup]	Stop dig from complaining about lack of IDN support when
 			the user asks for no IDN translation. [GL #3188]
 
-5825.	[funcf]		Set the minimum MTU on UDPv6 and TCPv6 sockets and
+5825.	[func]		Set the minimum MTU on UDPv6 and TCPv6 sockets and
 			limit TCP maximum segment size (TCP_MAXSEG) to (1220)
 			for both TCPv4 and TCPv6 sockets. [GL #2201]
 

doc/notes/notes-current.rst

@@ -106,3 +106,7 @@ Bug Fixes
   algorithm.  This is now checked for and the dnssec-policy is
   rejected if both roles are not present for all algorithms in use.
   :gl:`#3142`
+
+- Handling of the TCP write timeouts has been improved to track timeout
+  for each TCP write separately leading to faster connection tear down
+  in case the other party is not reading the data. :gl:`#3200`

lib/isc/httpd.c

@@ -700,7 +700,7 @@ new_httpd(isc_httpdmgr_t *httpdmgr, isc_nmhandle_t *handle) {
 	ISC_LIST_APPEND(httpdmgr->running, httpd, link);
 	UNLOCK(&httpdmgr->lock);
 
-	isc_nmhandle_attach(handle, &httpd->readhandle);
+	isc_nmhandle_attach(httpd->handle, &httpd->readhandle);
 	isc_nm_read(handle, httpd_request, httpdmgr);
 }
 
@@ -869,6 +869,7 @@ httpd_request(isc_nmhandle_t *handle, isc_result_t eresult,
 	httpd = isc_nmhandle_getdata(handle);
 
 	REQUIRE(httpd->state == RECV);
+	REQUIRE(httpd->handle == handle);
 
 	if (eresult != ISC_R_SUCCESS) {
 		goto cleanup_readhandle;
@@ -883,13 +884,13 @@ httpd_request(isc_nmhandle_t *handle, isc_result_t eresult,
 				/* don't unref, keep reading */
 				return;
 			}
+
 			/*
-			 * We have been called from httpd_senddone
-			 * and we need to resume reading.  Detach
-			 * readhandle before resuming.
+			 * We must have been called from httpd_senddone (as
+			 * ISC_R_NOTFOUND is not returned from netmgr) and we
+			 * need to resume reading.
 			 */
-			isc_nmhandle_detach(&httpd->readhandle);
-			isc_nm_resumeread(handle);
+			isc_nm_resumeread(httpd->readhandle);
 			return;
 		}
 		goto cleanup_readhandle;
@@ -1002,11 +1003,12 @@ httpd_request(isc_nmhandle_t *handle, isc_result_t eresult,
 	 */
 	isc_buffer_usedregion(httpd->sendbuffer, &r);
 
-	isc_nm_pauseread(handle);
+	isc_nm_pauseread(httpd->handle);
 	httpd->state = SEND;
 
-	isc_nmhandle_attach(handle, &httpd->sendhandle);
-	isc_nm_send(handle, &r, httpd_senddone, httpd);
+	isc_nmhandle_attach(httpd->handle, &httpd->sendhandle);
+	isc_nm_send(httpd->sendhandle, &r, httpd_senddone, httpd);
+	return;
 
 cleanup_readhandle:
 	isc_nmhandle_detach(&httpd->readhandle);
@@ -1158,6 +1160,7 @@ httpd_senddone(isc_nmhandle_t *handle, isc_result_t result, void *arg) {
 
 	REQUIRE(VALID_HTTPD(httpd));
 	REQUIRE(httpd->state == SEND);
+	REQUIRE(httpd->handle == handle);
 
 	isc_buffer_free(&httpd->sendbuffer);
 
@@ -1176,20 +1179,33 @@ httpd_senddone(isc_nmhandle_t *handle, isc_result_t result, void *arg) {
 	isc_nmhandle_detach(&httpd->sendhandle);
 
 	if (result != ISC_R_SUCCESS) {
-		return;
+		goto cleanup_readhandle;
+	}
+
+	if ((httpd->flags & HTTPD_CLOSE) != 0) {
+		goto cleanup_readhandle;
 	}
 
 	httpd->state = RECV;
+	httpd->sendhandle = NULL;
+
 	if (httpd->recvlen != 0) {
 		/*
 		 * Outstanding requests still exist, start processing
 		 * them.
 		 */
-		isc_nmhandle_attach(handle, &httpd->readhandle);
-		httpd_request(handle, ISC_R_SUCCESS, NULL, httpd->mgr);
+		httpd_request(httpd->handle, ISC_R_SUCCESS, NULL, httpd->mgr);
 	} else if (!httpd->truncated) {
-		isc_nm_resumeread(handle);
+		isc_nm_resumeread(httpd->readhandle);
+	} else {
+		/* Truncated request, don't resume */
+		goto cleanup_readhandle;
 	}
+
+	return;
+
+cleanup_readhandle:
+	isc_nmhandle_detach(&httpd->readhandle);
 }
 
 isc_result_t

lib/isc/netmgr/netmgr-int.h

@@ -377,15 +377,15 @@ struct isc__nm_uvreq {
 	int magic;
 	isc_nmsocket_t *sock;
 	isc_nmhandle_t *handle;
-	char tcplen[2];	      /* The TCP DNS message length */
-	uv_buf_t uvbuf;	      /* translated isc_region_t, to be
-			       * sent or received */
-	isc_sockaddr_t local; /* local address */
-	isc_sockaddr_t peer;  /* peer address */
-	isc__nm_cb_t cb;      /* callback */
-	void *cbarg;	      /* callback argument */
-	uv_pipe_t ipc;	      /* used for sending socket
-			       * uv_handles to other threads */
+	char tcplen[2];	       /* The TCP DNS message length */
+	uv_buf_t uvbuf;	       /* translated isc_region_t, to be
+				* sent or received */
+	isc_sockaddr_t local;  /* local address */
+	isc_sockaddr_t peer;   /* peer address */
+	isc__nm_cb_t cb;       /* callback */
+	void *cbarg;	       /* callback argument */
+	isc_nm_timer_t *timer; /* TCP write timer */
+
 	union {
 		uv_handle_t handle;
 		uv_req_t req;
@@ -972,9 +972,7 @@ struct isc_nmsocket {
 	/*%
 	 * TCP write timeout timer.
 	 */
-	uv_timer_t write_timer;
 	uint64_t write_timeout;
-	int64_t writes;
 
 	/*% outer socket is for 'wrapped' sockets - e.g. tcpdns in tcp */
 	isc_nmsocket_t *outer;
@@ -2097,7 +2095,7 @@ isc__nmsocket_connecttimeout_cb(uv_timer_t *timer);
 void
 isc__nmsocket_readtimeout_cb(uv_timer_t *timer);
 void
-isc__nmsocket_writetimeout_cb(uv_timer_t *timer);
+isc__nmsocket_writetimeout_cb(void *data, isc_result_t eresult);
 
 #define UV_RUNTIME_CHECK(func, ret)                                           \
 	if (ret != 0) {                                                       \

lib/isc/netmgr/netmgr.c

@@ -1985,11 +1985,15 @@ isc__nm_accept_connection_log(isc_result_t result, bool can_log_quota) {
 }
 
 void
-isc__nmsocket_writetimeout_cb(uv_timer_t *timer) {
-	isc_nmsocket_t *sock = uv_handle_get_data((uv_handle_t *)timer);
+isc__nmsocket_writetimeout_cb(void *data, isc_result_t eresult) {
+	isc__nm_uvreq_t *req = data;
+	isc_nmsocket_t *sock = NULL;
 
-	int r = uv_timer_stop(&sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_stop, r);
+	REQUIRE(eresult == ISC_R_TIMEDOUT);
+	REQUIRE(VALID_UVREQ(req));
+	REQUIRE(VALID_NMSOCK(req->sock));
+
+	sock = req->sock;
 
 	isc__nmsocket_reset(sock);
 }
@@ -2802,6 +2806,14 @@ isc__nm_async_detach(isc__networker_t *worker, isc__netievent_t *ev0) {
 	nmhandle_detach_cb(&ievent->handle FLARG_PASS);
 }
 
+static void
+reset_shutdown(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+
+	isc__nmsocket_shutdown(sock);
+	isc__nmsocket_detach(&sock);
+}
+
 void
 isc__nmsocket_reset(isc_nmsocket_t *sock) {
 	REQUIRE(VALID_NMSOCK(sock));
@@ -2822,15 +2834,20 @@ isc__nmsocket_reset(isc_nmsocket_t *sock) {
 		break;
 	}
 
-	if (!uv_is_closing(&sock->uv_handle.handle)) {
+	if (!uv_is_closing(&sock->uv_handle.handle) &&
+	    uv_is_active(&sock->uv_handle.handle))
+	{
 		/*
 		 * The real shutdown will be handled in the respective
 		 * close functions.
 		 */
-		int r = uv_tcp_close_reset(&sock->uv_handle.tcp, NULL);
+		isc__nmsocket_attach(sock, &(isc_nmsocket_t *){ NULL });
+		int r = uv_tcp_close_reset(&sock->uv_handle.tcp,
+					   reset_shutdown);
 		UV_RUNTIME_CHECK(uv_tcp_close_reset, r);
+	} else {
+		isc__nmsocket_shutdown(sock);
 	}
-	isc__nmsocket_shutdown(sock);
 }
 
 void
@@ -2871,13 +2888,27 @@ shutdown_walk_cb(uv_handle_t *handle, void *arg) {
 
 	switch (handle->type) {
 	case UV_UDP:
+		isc__nmsocket_shutdown(sock);
+		return;
 	case UV_TCP:
-		break;
+		switch (sock->type) {
+		case isc_nm_tcpsocket:
+		case isc_nm_tcpdnssocket:
+		case isc_nm_tlsdnssocket:
+			if (sock->parent == NULL) {
+				/* Reset the TCP connections on shutdown */
+				isc__nmsocket_reset(sock);
+				return;
+			}
+			/* FALLTHROUGH */
+		default:
+			isc__nmsocket_shutdown(sock);
+		}
+
+		return;
 	default:
 		return;
 	}
-
-	isc__nmsocket_shutdown(sock);
 }
 
 void

lib/isc/netmgr/tcp.c

@@ -78,9 +78,6 @@ quota_accept_cb(isc_quota_t *quota, void *sock0);
 static void
 failed_accept_cb(isc_nmsocket_t *sock, isc_result_t eresult);
 
-static void
-failed_send_cb(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
-	       isc_result_t eresult);
 static void
 stop_tcp_parent(isc_nmsocket_t *sock);
 static void
@@ -144,10 +141,6 @@ tcp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
 
-	r = uv_timer_init(&worker->loop, &sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-
 	r = uv_tcp_open(&sock->uv_handle.tcp, sock->fd);
 	if (r != 0) {
 		isc__nm_closesocket(sock->fd);
@@ -542,10 +535,6 @@ isc__nm_async_tcplisten(isc__networker_t *worker, isc__netievent_t *ev0) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
 
-	r = uv_timer_init(&worker->loop, &sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-
 	LOCK(&sock->parent->lock);
 
 	r = uv_tcp_open(&sock->uv_handle.tcp, sock->fd);
@@ -718,19 +707,6 @@ destroy:
 	}
 }
 
-static void
-failed_send_cb(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
-	       isc_result_t eresult) {
-	REQUIRE(VALID_NMSOCK(sock));
-	REQUIRE(VALID_UVREQ(req));
-
-	if (req->cb.send != NULL) {
-		isc__nm_sendcb(sock, req, eresult, true);
-	} else {
-		isc__nm_uvreq_put(&req, sock);
-	}
-}
-
 void
 isc__nm_tcp_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
 	REQUIRE(VALID_NMHANDLE(handle));
@@ -992,10 +968,6 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&csock->read_timer, csock);
 
-	r = uv_timer_init(&worker->loop, &csock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&csock->write_timer, csock);
-
 	r = uv_accept(&ssock->uv_handle.stream, &csock->uv_handle.stream);
 	if (r != 0) {
 		result = isc__nm_uverr2result(r);
@@ -1106,20 +1078,20 @@ isc__nm_tcp_send(isc_nmhandle_t *handle, const isc_region_t *region,
 static void
 tcp_send_cb(uv_write_t *req, int status) {
 	isc__nm_uvreq_t *uvreq = (isc__nm_uvreq_t *)req->data;
+	isc_nmsocket_t *sock = NULL;
 
 	REQUIRE(VALID_UVREQ(uvreq));
-	REQUIRE(VALID_NMHANDLE(uvreq->handle));
+	REQUIRE(VALID_NMSOCK(uvreq->sock));
 
-	isc_nmsocket_t *sock = uvreq->sock;
+	sock = uvreq->sock;
 
-	if (--sock->writes == 0) {
-		int r = uv_timer_stop(&sock->write_timer);
-		UV_RUNTIME_CHECK(uv_timer_stop, r);
-	}
+	isc_nm_timer_stop(uvreq->timer);
+	isc_nm_timer_detach(&uvreq->timer);
 
 	if (status < 0) {
 		isc__nm_incstats(sock, STATID_SENDFAIL);
-		failed_send_cb(sock, uvreq, isc__nm_uverr2result(status));
+		isc__nm_failed_send_cb(sock, uvreq,
+				       isc__nm_uverr2result(status));
 		return;
 	}
 
@@ -1143,7 +1115,7 @@ isc__nm_async_tcpsend(isc__networker_t *worker, isc__netievent_t *ev0) {
 	result = tcp_send_direct(sock, uvreq);
 	if (result != ISC_R_SUCCESS) {
 		isc__nm_incstats(sock, STATID_SENDFAIL);
-		failed_send_cb(sock, uvreq, result);
+		isc__nm_failed_send_cb(sock, uvreq, result);
 	}
 }
 
@@ -1160,17 +1132,18 @@ tcp_send_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 		return (ISC_R_CANCELED);
 	}
 
-	r = uv_timer_start(&sock->write_timer, isc__nmsocket_writetimeout_cb,
-			   sock->write_timeout, 0);
-	UV_RUNTIME_CHECK(uv_timer_start, r);
-	RUNTIME_CHECK(sock->writes++ >= 0);
-
 	r = uv_write(&req->uv_req.write, &sock->uv_handle.stream, &req->uvbuf,
 		     1, tcp_send_cb);
 	if (r < 0) {
 		return (isc__nm_uverr2result(r));
 	}
 
+	isc_nm_timer_create(req->handle, isc__nmsocket_writetimeout_cb, req,
+			    &req->timer);
+	if (sock->write_timeout > 0) {
+		isc_nm_timer_start(req->timer, sock->write_timeout);
+	}
+
 	return (ISC_R_SUCCESS);
 }
 
@@ -1241,17 +1214,6 @@ read_timer_close_cb(uv_handle_t *handle) {
 	}
 }
 
-static void
-write_timer_close_cb(uv_handle_t *timer) {
-	isc_nmsocket_t *sock = uv_handle_get_data(timer);
-	uv_handle_set_data(timer, NULL);
-
-	REQUIRE(VALID_NMSOCK(sock));
-
-	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
-	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
-}
-
 static void
 stop_tcp_child(isc_nmsocket_t *sock) {
 	REQUIRE(sock->type == isc_nm_tcpsocket);
@@ -1304,8 +1266,6 @@ stop_tcp_parent(isc_nmsocket_t *sock) {
 
 static void
 tcp_close_direct(isc_nmsocket_t *sock) {
-	int r;
-
 	REQUIRE(VALID_NMSOCK(sock));
 	REQUIRE(sock->tid == isc_nm_tid());
 	REQUIRE(atomic_load(&sock->closing));
@@ -1327,10 +1287,8 @@ tcp_close_direct(isc_nmsocket_t *sock) {
 	isc__nmsocket_timer_stop(sock);
 	isc__nm_stop_reading(sock);
 
-	r = uv_timer_stop(&sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_stop, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-	uv_close((uv_handle_t *)&sock->write_timer, write_timer_close_cb);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
 }
 
 void

lib/isc/netmgr/tcpdns.c

@@ -102,10 +102,6 @@ tcpdns_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
 
-	r = uv_timer_init(&worker->loop, &sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-
 	if (isc__nm_closing(sock)) {
 		result = ISC_R_SHUTTINGDOWN;
 		goto error;
@@ -505,10 +501,6 @@ isc__nm_async_tcpdnslisten(isc__networker_t *worker, isc__netievent_t *ev0) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
 
-	r = uv_timer_init(&worker->loop, &sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-
 	LOCK(&sock->parent->lock);
 
 	r = uv_tcp_open(&sock->uv_handle.tcp, sock->fd);
@@ -978,10 +970,6 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&csock->read_timer, csock);
 
-	r = uv_timer_init(&worker->loop, &csock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&csock->write_timer, csock);
-
 	r = uv_accept(&ssock->uv_handle.stream, &csock->uv_handle.stream);
 	if (r != 0) {
 		result = isc__nm_uverr2result(r);
@@ -1118,14 +1106,12 @@ tcpdns_send_cb(uv_write_t *req, int status) {
 	isc_nmsocket_t *sock = NULL;
 
 	REQUIRE(VALID_UVREQ(uvreq));
-	REQUIRE(VALID_NMHANDLE(uvreq->handle));
+	REQUIRE(VALID_NMSOCK(uvreq->sock));
 
 	sock = uvreq->sock;
 
-	if (--sock->writes == 0) {
-		int r = uv_timer_stop(&sock->write_timer);
-		UV_RUNTIME_CHECK(uv_timer_stop, r);
-	}
+	isc_nm_timer_stop(uvreq->timer);
+	isc_nm_timer_detach(&uvreq->timer);
 
 	if (status < 0) {
 		isc__nm_incstats(sock, STATID_SENDFAIL);
@@ -1193,11 +1179,6 @@ isc__nm_async_tcpdnssend(isc__networker_t *worker, isc__netievent_t *ev0) {
 		goto fail;
 	}
 
-	r = uv_timer_start(&sock->write_timer, isc__nmsocket_writetimeout_cb,
-			   sock->write_timeout, 0);
-	UV_RUNTIME_CHECK(uv_timer_start, r);
-	RUNTIME_CHECK(sock->writes++ >= 0);
-
 	r = uv_write(&uvreq->uv_req.write, &sock->uv_handle.stream, bufs, nbufs,
 		     tcpdns_send_cb);
 	if (r < 0) {
@@ -1205,6 +1186,12 @@ isc__nm_async_tcpdnssend(isc__networker_t *worker, isc__netievent_t *ev0) {
 		goto fail;
 	}
 
+	isc_nm_timer_create(uvreq->handle, isc__nmsocket_writetimeout_cb, uvreq,
+			    &uvreq->timer);
+	if (sock->write_timeout > 0) {
+		isc_nm_timer_start(uvreq->timer, sock->write_timeout);
+	}
+
 	return;
 fail:
 	isc__nm_incstats(sock, STATID_SENDFAIL);
@@ -1282,17 +1269,6 @@ read_timer_close_cb(uv_handle_t *timer) {
 	}
 }
 
-static void
-write_timer_close_cb(uv_handle_t *timer) {
-	isc_nmsocket_t *sock = uv_handle_get_data(timer);
-	uv_handle_set_data(timer, NULL);
-
-	REQUIRE(VALID_NMSOCK(sock));
-
-	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
-	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
-}
-
 static void
 stop_tcpdns_child(isc_nmsocket_t *sock) {
 	REQUIRE(sock->type == isc_nm_tcpdnssocket);
@@ -1345,7 +1321,6 @@ stop_tcpdns_parent(isc_nmsocket_t *sock) {
 
 static void
 tcpdns_close_direct(isc_nmsocket_t *sock) {
-	int r;
 	REQUIRE(VALID_NMSOCK(sock));
 	REQUIRE(sock->tid == isc_nm_tid());
 	REQUIRE(atomic_load(&sock->closing));
@@ -1361,10 +1336,8 @@ tcpdns_close_direct(isc_nmsocket_t *sock) {
 	isc__nmsocket_timer_stop(sock);
 	isc__nm_stop_reading(sock);
 
-	r = uv_timer_stop(&sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_stop, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-	uv_close((uv_handle_t *)&sock->write_timer, write_timer_close_cb);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
 }
 
 void

lib/isc/netmgr/timer.c

@@ -41,6 +41,7 @@ isc_nm_timer_create(isc_nmhandle_t *handle, isc_nm_timer_cb cb, void *cbarg,
 	sock = handle->sock;
 	worker = &sock->mgr->workers[isc_nm_tid()];
 
+	/* TODO: per-loop object cache */
 	timer = isc_mem_get(sock->mgr->mctx, sizeof(*timer));
 	*timer = (isc_nm_timer_t){ .cb = cb, .cbarg = cbarg };
 	isc_refcount_init(&timer->references, 1);
@@ -91,7 +92,8 @@ isc_nm_timer_detach(isc_nm_timer_t **timerp) {
 	REQUIRE(VALID_NMSOCK(handle->sock));
 
 	if (isc_refcount_decrement(&timer->references) == 1) {
-		uv_timer_stop(&timer->timer);
+		int r = uv_timer_stop(&timer->timer);
+		UV_RUNTIME_CHECK(uv_timer_stop, r);
 		uv_close((uv_handle_t *)&timer->timer, timer_destroy);
 	}
 }

lib/isc/netmgr/tlsdns.c

@@ -118,10 +118,6 @@ tlsdns_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
 
-	r = uv_timer_init(&worker->loop, &sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-
 	if (isc__nm_closing(sock)) {
 		result = ISC_R_SHUTTINGDOWN;
 		goto error;
@@ -576,10 +572,6 @@ isc__nm_async_tlsdnslisten(isc__networker_t *worker, isc__netievent_t *ev0) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
 
-	r = uv_timer_init(&worker->loop, &sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-
 	LOCK(&sock->parent->lock);
 
 	r = uv_tcp_open(&sock->uv_handle.tcp, sock->fd);
@@ -1171,10 +1163,8 @@ tls_write_cb(uv_write_t *req, int status) {
 	isc__nm_uvreq_t *uvreq = (isc__nm_uvreq_t *)req->data;
 	isc_nmsocket_t *sock = uvreq->sock;
 
-	if (--sock->writes == 0) {
-		int r = uv_timer_stop(&sock->write_timer);
-		UV_RUNTIME_CHECK(uv_timer_stop, r);
-	}
+	isc_nm_timer_stop(uvreq->timer);
+	isc_nm_timer_detach(&uvreq->timer);
 
 	free_senddata(sock);
 
@@ -1215,7 +1205,8 @@ tls_cycle_output(isc_nmsocket_t *sock) {
 		sock->tls.senddata.base = isc_mem_get(sock->mgr->mctx, pending);
 		sock->tls.senddata.length = pending;
 
-		req = isc__nm_uvreq_get(sock->mgr, sock);
+		/* It's a bit misnomer here, but it does the right thing */
+		req = isc__nm_get_read_req(sock, NULL);
 		req->uvbuf.base = (char *)sock->tls.senddata.base;
 		req->uvbuf.len = sock->tls.senddata.length;
 
@@ -1249,12 +1240,6 @@ tls_cycle_output(isc_nmsocket_t *sock) {
 			break;
 		}
 
-		r = uv_timer_start(&sock->write_timer,
-				   isc__nmsocket_writetimeout_cb,
-				   sock->write_timeout, 0);
-		UV_RUNTIME_CHECK(uv_timer_start, r);
-		RUNTIME_CHECK(sock->writes++ >= 0);
-
 		r = uv_write(&req->uv_req.write, &sock->uv_handle.stream,
 			     &req->uvbuf, 1, tls_write_cb);
 		if (r < 0) {
@@ -1264,6 +1249,12 @@ tls_cycle_output(isc_nmsocket_t *sock) {
 			break;
 		}
 
+		isc_nm_timer_create(req->handle, isc__nmsocket_writetimeout_cb,
+				    req, &req->timer);
+		if (sock->write_timeout > 0) {
+			isc_nm_timer_start(req->timer, sock->write_timeout);
+		}
+
 		break;
 	}
 
@@ -1499,10 +1490,6 @@ accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&csock->read_timer, csock);
 
-	r = uv_timer_init(&worker->loop, &csock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&csock->write_timer, csock);
-
 	r = uv_accept(&ssock->uv_handle.stream, &csock->uv_handle.stream);
 	if (r != 0) {
 		result = isc__nm_uverr2result(r);
@@ -1849,17 +1836,6 @@ read_timer_close_cb(uv_handle_t *handle) {
 	}
 }
 
-static void
-write_timer_close_cb(uv_handle_t *timer) {
-	isc_nmsocket_t *sock = uv_handle_get_data(timer);
-	uv_handle_set_data(timer, NULL);
-
-	REQUIRE(VALID_NMSOCK(sock));
-
-	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
-	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
-}
-
 static void
 stop_tlsdns_child(isc_nmsocket_t *sock) {
 	REQUIRE(sock->type == isc_nm_tlsdnssocket);
@@ -1913,8 +1889,6 @@ stop_tlsdns_parent(isc_nmsocket_t *sock) {
 
 static void
 tlsdns_close_direct(isc_nmsocket_t *sock) {
-	int r;
-
 	REQUIRE(VALID_NMSOCK(sock));
 	REQUIRE(sock->tid == isc_nm_tid());
 	REQUIRE(atomic_load(&sock->closing));
@@ -1932,10 +1906,8 @@ tlsdns_close_direct(isc_nmsocket_t *sock) {
 	isc__nmsocket_timer_stop(sock);
 	isc__nm_stop_reading(sock);
 
-	r = uv_timer_stop(&sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_stop, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-	uv_close((uv_handle_t *)&sock->write_timer, write_timer_close_cb);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
 }
 
 void

lib/isc/netmgr/udp.c

@@ -76,9 +76,6 @@ udp_close_cb(uv_handle_t *handle);
 static void
 read_timer_close_cb(uv_handle_t *handle);
 
-static void
-write_timer_close_cb(uv_handle_t *handle);
-
 static void
 udp_close_direct(isc_nmsocket_t *sock);
 
@@ -272,10 +269,6 @@ route_connect_direct(isc_nmsocket_t *sock) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
 
-	r = uv_timer_init(&worker->loop, &sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-
 	if (isc__nm_closing(sock)) {
 		result = ISC_R_SHUTTINGDOWN;
 		goto error;
@@ -454,10 +447,6 @@ isc__nm_async_udplisten(isc__networker_t *worker, isc__netievent_t *ev0) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
 
-	r = uv_timer_init(&worker->loop, &sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-
 	LOCK(&sock->parent->lock);
 
 	r = uv_udp_open(&sock->uv_handle.udp, sock->fd);
@@ -874,10 +863,6 @@ udp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	UV_RUNTIME_CHECK(uv_timer_init, r);
 	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
 
-	r = uv_timer_init(&worker->loop, &sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_init, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-
 	if (isc__nm_closing(sock)) {
 		result = ISC_R_SHUTTINGDOWN;
 		goto error;
@@ -1240,17 +1225,6 @@ read_timer_close_cb(uv_handle_t *handle) {
 	}
 }
 
-static void
-write_timer_close_cb(uv_handle_t *timer) {
-	isc_nmsocket_t *sock = uv_handle_get_data(timer);
-	uv_handle_set_data(timer, NULL);
-
-	REQUIRE(VALID_NMSOCK(sock));
-
-	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
-	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
-}
-
 static void
 stop_udp_child(isc_nmsocket_t *sock) {
 	REQUIRE(sock->type == isc_nm_udpsocket);
@@ -1303,14 +1277,11 @@ stop_udp_parent(isc_nmsocket_t *sock) {
 
 static void
 udp_close_direct(isc_nmsocket_t *sock) {
-	int r;
 	REQUIRE(VALID_NMSOCK(sock));
 	REQUIRE(sock->tid == isc_nm_tid());
 
-	r = uv_timer_stop(&sock->write_timer);
-	UV_RUNTIME_CHECK(uv_timer_stop, r);
-	uv_handle_set_data((uv_handle_t *)&sock->write_timer, sock);
-	uv_close((uv_handle_t *)&sock->write_timer, write_timer_close_cb);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
 }
 
 void