Adding upstream version 1:9.16.44.upstream/1%9.16.44

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

9 files changed, 9606 insertions, 0 deletions

diff --git a/lib/isc/netmgr/Makefile.in b/lib/isc/netmgr/Makefile.in
new file mode 100644
index 0000000..1806cb4
--- /dev/null
+++ b/lib/isc/netmgr/Makefile.in
@@ -0,0 +1,41 @@
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# SPDX-License-Identifier: MPL-2.0
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0.  If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+srcdir =	@srcdir@
+VPATH =		@srcdir@
+top_srcdir =	@top_srcdir@
+
+CINCLUDES =	-I${srcdir}/include \
+		-I${srcdir}/../unix/include \
+		-I${srcdir}/../pthreads/include \
+		-I../include \
+		-I${srcdir}/../include \
+		-I${srcdir}/.. \
+		${OPENSSL_CFLAGS} \
+		${JSON_C_CFLAGS} \
+		${LIBUV_CFLAGS} \
+		${LIBXML2_CFLAGS}
+
+CDEFINES =
+CWARNINGS =
+
+# Alphabetically
+OBJS =		netmgr.@O@ tcp.@O@ udp.@O@ \
+		tcpdns.@O@ \
+		uverr2result.@O@ uv-compat.@O@
+
+# Alphabetically
+SRCS =		netmgr.c tcp.c udp.c tcpdns.c \
+		uverr2result.c uv-compat.c
+
+TARGETS =	${OBJS}
+
+@BIND9_MAKE_RULES@
diff --git a/lib/isc/netmgr/netmgr-int.h b/lib/isc/netmgr/netmgr-int.h
new file mode 100644
index 0000000..05fde1a
--- /dev/null
+++ b/lib/isc/netmgr/netmgr-int.h
@@ -0,0 +1,1615 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#pragma once
+
+#include <unistd.h>
+#include <uv.h>
+
+#include <openssl/err.h>
+#include <openssl/ssl.h>
+
+#include <isc/astack.h>
+#include <isc/atomic.h>
+#include <isc/barrier.h>
+#include <isc/buffer.h>
+#include <isc/condition.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/netmgr.h>
+#include <isc/quota.h>
+#include <isc/random.h>
+#include <isc/refcount.h>
+#include <isc/region.h>
+#include <isc/result.h>
+#include <isc/rwlock.h>
+#include <isc/sockaddr.h>
+#include <isc/stats.h>
+#include <isc/thread.h>
+#include <isc/util.h>
+
+#include "uv-compat.h"
+
+#define ISC_NETMGR_TID_UNKNOWN -1
+
+/* Must be different from ISC_NETMGR_TID_UNKNOWN */
+#define ISC_NETMGR_NON_INTERLOCKED -2
+
+/*
+ * Receive buffers
+ */
+#if HAVE_DECL_UV_UDP_MMSG_CHUNK
+/*
+ * The value 20 here is UV__MMSG_MAXWIDTH taken from the current libuv source,
+ * libuv will not receive more that 20 datagrams in a single recvmmsg call.
+ */
+#define ISC_NETMGR_UDP_RECVBUF_SIZE (20 * UINT16_MAX)
+#else
+/*
+ * A single DNS message size
+ */
+#define ISC_NETMGR_UDP_RECVBUF_SIZE UINT16_MAX
+#endif
+
+/*
+ * The TCP receive buffer can fit one maximum sized DNS message plus its size,
+ * the receive buffer here affects TCP, DoT and DoH.
+ */
+#define ISC_NETMGR_TCP_RECVBUF_SIZE (sizeof(uint16_t) + UINT16_MAX)
+
+/* Pick the larger buffer */
+#define ISC_NETMGR_RECVBUF_SIZE                                     \
+	(ISC_NETMGR_UDP_RECVBUF_SIZE >= ISC_NETMGR_TCP_RECVBUF_SIZE \
+		 ? ISC_NETMGR_UDP_RECVBUF_SIZE                      \
+		 : ISC_NETMGR_TCP_RECVBUF_SIZE)
+
+/*
+ * Send buffer
+ */
+#define ISC_NETMGR_SENDBUF_SIZE (sizeof(uint16_t) + UINT16_MAX)
+
+/*%
+ * Regular TCP buffer size.
+ */
+#define NM_REG_BUF 4096
+
+/*%
+ * Larger buffer for when the regular one isn't enough; this will
+ * hold two full DNS packets with lengths.  netmgr receives 64k at
+ * most in TCPDNS connections, so there's no risk of overrun
+ * when using a buffer this size.
+ */
+#define NM_BIG_BUF ISC_NETMGR_TCP_RECVBUF_SIZE * 2
+
+/*
+ * Define NETMGR_TRACE to activate tracing of handles and sockets.
+ * This will impair performance but enables us to quickly determine,
+ * if netmgr resources haven't been cleaned up on shutdown, which ones
+ * are still in use.
+ */
+#ifdef NETMGR_TRACE
+#define TRACE_SIZE 8
+
+void
+isc__nm_dump_active(isc_nm_t *nm);
+
+#if defined(__linux__)
+#include <syscall.h>
+#define gettid() (uint32_t) syscall(SYS_gettid)
+#elif defined(_WIN32)
+#define gettid() (uint32_t) GetCurrentThreadId()
+#else
+#define gettid() (uint32_t) pthread_self()
+#endif
+
+#ifdef NETMGR_TRACE_VERBOSE
+#define NETMGR_TRACE_LOG(format, ...)                                \
+	fprintf(stderr, "%" PRIu32 ":%d:%s:%u:%s:" format, gettid(), \
+		isc_nm_tid(), file, line, func, __VA_ARGS__)
+#else
+#define NETMGR_TRACE_LOG(format, ...) \
+	(void)file;                   \
+	(void)line;                   \
+	(void)func;
+#endif
+
+#define FLARG_PASS , file, line, func
+#define FLARG                                              \
+	, const char *file __attribute__((unused)),        \
+		unsigned int line __attribute__((unused)), \
+		const char *func __attribute__((unused))
+#define FLARG_IEVENT(ievent)              \
+	const char *file = ievent->file;  \
+	unsigned int line = ievent->line; \
+	const char *func = ievent->func;
+#define FLARG_IEVENT_PASS(ievent) \
+	ievent->file = file;      \
+	ievent->line = line;      \
+	ievent->func = func;
+#define isc__nm_uvreq_get(req, sock) \
+	isc___nm_uvreq_get(req, sock, __FILE__, __LINE__, __func__)
+#define isc__nm_uvreq_put(req, sock) \
+	isc___nm_uvreq_put(req, sock, __FILE__, __LINE__, __func__)
+#define isc__nmsocket_init(sock, mgr, type, iface)                      \
+	isc___nmsocket_init(sock, mgr, type, iface, __FILE__, __LINE__, \
+			    __func__)
+#define isc__nmsocket_put(sockp) \
+	isc___nmsocket_put(sockp, __FILE__, __LINE__, __func__)
+#define isc__nmsocket_attach(sock, target) \
+	isc___nmsocket_attach(sock, target, __FILE__, __LINE__, __func__)
+#define isc__nmsocket_detach(socketp) \
+	isc___nmsocket_detach(socketp, __FILE__, __LINE__, __func__)
+#define isc__nmsocket_close(socketp) \
+	isc___nmsocket_close(socketp, __FILE__, __LINE__, __func__)
+#define isc__nmhandle_get(sock, peer, local) \
+	isc___nmhandle_get(sock, peer, local, __FILE__, __LINE__, __func__)
+#define isc__nmsocket_prep_destroy(sock) \
+	isc___nmsocket_prep_destroy(sock, __FILE__, __LINE__, __func__)
+#else
+#define NETMGR_TRACE_LOG(format, ...)
+
+#define FLARG_PASS
+#define FLARG
+#define FLARG_IEVENT(ievent)
+#define FLARG_IEVENT_PASS(ievent)
+#define isc__nm_uvreq_get(req, sock) isc___nm_uvreq_get(req, sock)
+#define isc__nm_uvreq_put(req, sock) isc___nm_uvreq_put(req, sock)
+#define isc__nmsocket_init(sock, mgr, type, iface) \
+	isc___nmsocket_init(sock, mgr, type, iface)
+#define isc__nmsocket_put(sockp)	   isc___nmsocket_put(sockp)
+#define isc__nmsocket_attach(sock, target) isc___nmsocket_attach(sock, target)
+#define isc__nmsocket_detach(socketp)	   isc___nmsocket_detach(socketp)
+#define isc__nmsocket_close(socketp)	   isc___nmsocket_close(socketp)
+#define isc__nmhandle_get(sock, peer, local) \
+	isc___nmhandle_get(sock, peer, local)
+#define isc__nmsocket_prep_destroy(sock) isc___nmsocket_prep_destroy(sock)
+#endif
+
+/*
+ * Queue types in the order of processing priority.
+ */
+typedef enum {
+	NETIEVENT_PRIORITY = 0,
+	NETIEVENT_PRIVILEGED = 1,
+	NETIEVENT_TASK = 2,
+	NETIEVENT_NORMAL = 3,
+	NETIEVENT_MAX = 4,
+} netievent_type_t;
+
+typedef struct isc__nm_uvreq isc__nm_uvreq_t;
+typedef struct isc__netievent isc__netievent_t;
+
+typedef ISC_LIST(isc__netievent_t) isc__netievent_list_t;
+
+typedef struct ievent {
+	isc_mutex_t lock;
+	isc_condition_t cond;
+	isc__netievent_list_t list;
+} ievent_t;
+
+/*
+ * Single network event loop worker.
+ */
+typedef struct isc__networker {
+	isc_nm_t *mgr;
+	int id;		  /* thread id */
+	uv_loop_t loop;	  /* libuv loop structure */
+	uv_async_t async; /* async channel to send
+			   * data to this networker */
+	bool paused;
+	bool finished;
+	isc_thread_t thread;
+	ievent_t ievents[NETIEVENT_MAX];
+
+	isc_refcount_t references;
+	atomic_int_fast64_t pktcount;
+	char *recvbuf;
+	char *sendbuf;
+	bool recvbuf_inuse;
+} isc__networker_t;
+
+/*
+ * A general handle for a connection bound to a networker.  For UDP
+ * connections we have peer address here, so both TCP and UDP can be
+ * handled with a simple send-like function
+ */
+#define NMHANDLE_MAGIC ISC_MAGIC('N', 'M', 'H', 'D')
+#define VALID_NMHANDLE(t)                      \
+	(ISC_MAGIC_VALID(t, NMHANDLE_MAGIC) && \
+	 atomic_load(&(t)->references) > 0)
+
+typedef void (*isc__nm_closecb)(isc_nmhandle_t *);
+
+struct isc_nmhandle {
+	int magic;
+	isc_refcount_t references;
+
+	/*
+	 * The socket is not 'attached' in the traditional
+	 * reference-counting sense. Instead, we keep all handles in an
+	 * array in the socket object.  This way, we don't have circular
+	 * dependencies and we can close all handles when we're destroying
+	 * the socket.
+	 */
+	isc_nmsocket_t *sock;
+
+	isc_sockaddr_t peer;
+	isc_sockaddr_t local;
+	isc_nm_opaquecb_t doreset; /* reset extra callback, external */
+	isc_nm_opaquecb_t dofree;  /* free extra callback, external */
+#ifdef NETMGR_TRACE
+	void *backtrace[TRACE_SIZE];
+	int backtrace_size;
+	LINK(isc_nmhandle_t) active_link;
+#endif
+	void *opaque;
+	char extra[];
+};
+
+typedef enum isc__netievent_type {
+	netievent_udpconnect,
+	netievent_udpclose,
+	netievent_udpsend,
+	netievent_udpread,
+	netievent_udpcancel,
+
+	netievent_tcpconnect,
+	netievent_tcpclose,
+	netievent_tcpsend,
+	netievent_tcpstartread,
+	netievent_tcppauseread,
+	netievent_tcpaccept,
+	netievent_tcpcancel,
+
+	netievent_tcpdnsaccept,
+	netievent_tcpdnsconnect,
+	netievent_tcpdnsclose,
+	netievent_tcpdnssend,
+	netievent_tcpdnsread,
+	netievent_tcpdnscancel,
+
+	netievent_shutdown,
+	netievent_stop,
+	netievent_pause,
+
+	netievent_connectcb,
+	netievent_readcb,
+	netievent_sendcb,
+
+	netievent_detach,
+	netievent_close,
+
+	netievent_task,
+	netievent_privilegedtask,
+
+	/*
+	 * event type values higher than this will be treated
+	 * as high-priority events, which can be processed
+	 * while the netmgr is pausing or paused.
+	 */
+	netievent_prio = 0xff,
+
+	netievent_udplisten,
+	netievent_udpstop,
+	netievent_tcplisten,
+	netievent_tcpstop,
+	netievent_tcpdnslisten,
+	netievent_tcpdnsstop,
+
+	netievent_resume,
+} isc__netievent_type;
+
+typedef union {
+	isc_nm_recv_cb_t recv;
+	isc_nm_cb_t send;
+	isc_nm_cb_t connect;
+	isc_nm_accept_cb_t accept;
+} isc__nm_cb_t;
+
+/*
+ * Wrapper around uv_req_t with 'our' fields in it.  req->data should
+ * always point to its parent.  Note that we always allocate more than
+ * sizeof(struct) because we make room for different req types;
+ */
+#define UVREQ_MAGIC    ISC_MAGIC('N', 'M', 'U', 'R')
+#define VALID_UVREQ(t) ISC_MAGIC_VALID(t, UVREQ_MAGIC)
+
+typedef struct isc__nm_uvreq isc__nm_uvreq_t;
+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 */
+	isc_nm_timer_t *timer; /* TCP write timer */
+
+	union {
+		uv_handle_t handle;
+		uv_req_t req;
+		uv_getaddrinfo_t getaddrinfo;
+		uv_getnameinfo_t getnameinfo;
+		uv_shutdown_t shutdown;
+		uv_write_t write;
+		uv_connect_t connect;
+		uv_udp_send_t udp_send;
+		uv_fs_t fs;
+		uv_work_t work;
+	} uv_req;
+	ISC_LINK(isc__nm_uvreq_t) link;
+};
+
+struct isc_nm_timer {
+	isc_refcount_t references;
+	uv_timer_t timer;
+	isc_nmhandle_t *handle;
+	isc_nm_timer_cb cb;
+	void *cbarg;
+};
+
+void *
+isc__nm_get_netievent(isc_nm_t *mgr, isc__netievent_type type);
+/*%<
+ * Allocate an ievent and set the type.
+ */
+void
+isc__nm_put_netievent(isc_nm_t *mgr, void *ievent);
+
+/*
+ * The macros here are used to simulate the "inheritance" in C, there's the base
+ * netievent structure that contains just its own type and socket, and there are
+ * extended netievent types that also have handles or requests or other data.
+ *
+ * The macros here ensure that:
+ *
+ *   1. every netievent type has matching definition, declaration and
+ *      implementation
+ *
+ *   2. we handle all the netievent types of same subclass the same, e.g. if the
+ *      extended netievent contains handle, we always attach to the handle in
+ *      the ctor and detach from the handle in dtor.
+ *
+ * There are three macros here for each netievent subclass:
+ *
+ *   1. NETIEVENT_*_TYPE(type) creates the typedef for each type; used below in
+ *   this header
+ *
+ *   2. NETIEVENT_*_DECL(type) generates the declaration of the get and put
+ *      functions (isc__nm_get_netievent_* and isc__nm_put_netievent_*); used
+ *      below in this header
+ *
+ *   3. NETIEVENT_*_DEF(type) generates the definition of the functions; used
+ *   either in netmgr.c or matching protocol file (e.g. udp.c, tcp.c, etc.)
+ */
+
+#define NETIEVENT__SOCKET                \
+	isc__netievent_type type;        \
+	ISC_LINK(isc__netievent_t) link; \
+	isc_nmsocket_t *sock;            \
+	const char *file;                \
+	unsigned int line;               \
+	const char *func
+
+typedef struct isc__netievent__socket {
+	NETIEVENT__SOCKET;
+} isc__netievent__socket_t;
+
+#define NETIEVENT_SOCKET_TYPE(type) \
+	typedef isc__netievent__socket_t isc__netievent_##type##_t;
+
+#define NETIEVENT_SOCKET_DECL(type)                              \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type( \
+		isc_nm_t *nm, isc_nmsocket_t *sock);             \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,          \
+					  isc__netievent_##type##_t *ievent);
+
+#define NETIEVENT_SOCKET_DEF(type)                                             \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(               \
+		isc_nm_t *nm, isc_nmsocket_t *sock) {                          \
+		isc__netievent_##type##_t *ievent =                            \
+			isc__nm_get_netievent(nm, netievent_##type);           \
+		isc__nmsocket_attach(sock, &ievent->sock);                     \
+                                                                               \
+		return (ievent);                                               \
+	}                                                                      \
+                                                                               \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                        \
+					  isc__netievent_##type##_t *ievent) { \
+		isc__nmsocket_detach(&ievent->sock);                           \
+		isc__nm_put_netievent(nm, ievent);                             \
+	}
+
+typedef struct isc__netievent__socket_req {
+	NETIEVENT__SOCKET;
+	isc__nm_uvreq_t *req;
+} isc__netievent__socket_req_t;
+
+#define NETIEVENT_SOCKET_REQ_TYPE(type) \
+	typedef isc__netievent__socket_req_t isc__netievent_##type##_t;
+
+#define NETIEVENT_SOCKET_REQ_DECL(type)                                    \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(           \
+		isc_nm_t *nm, isc_nmsocket_t *sock, isc__nm_uvreq_t *req); \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                    \
+					  isc__netievent_##type##_t *ievent);
+
+#define NETIEVENT_SOCKET_REQ_DEF(type)                                         \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(               \
+		isc_nm_t *nm, isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {    \
+		isc__netievent_##type##_t *ievent =                            \
+			isc__nm_get_netievent(nm, netievent_##type);           \
+		isc__nmsocket_attach(sock, &ievent->sock);                     \
+		ievent->req = req;                                             \
+                                                                               \
+		return (ievent);                                               \
+	}                                                                      \
+                                                                               \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                        \
+					  isc__netievent_##type##_t *ievent) { \
+		isc__nmsocket_detach(&ievent->sock);                           \
+		isc__nm_put_netievent(nm, ievent);                             \
+	}
+
+typedef struct isc__netievent__socket_req_result {
+	NETIEVENT__SOCKET;
+	isc__nm_uvreq_t *req;
+	isc_result_t result;
+} isc__netievent__socket_req_result_t;
+
+#define NETIEVENT_SOCKET_REQ_RESULT_TYPE(type) \
+	typedef isc__netievent__socket_req_result_t isc__netievent_##type##_t;
+
+#define NETIEVENT_SOCKET_REQ_RESULT_DECL(type)                            \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(          \
+		isc_nm_t *nm, isc_nmsocket_t *sock, isc__nm_uvreq_t *req, \
+		isc_result_t result);                                     \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                   \
+					  isc__netievent_##type##_t *ievent);
+
+#define NETIEVENT_SOCKET_REQ_RESULT_DEF(type)                                  \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(               \
+		isc_nm_t *nm, isc_nmsocket_t *sock, isc__nm_uvreq_t *req,      \
+		isc_result_t result) {                                         \
+		isc__netievent_##type##_t *ievent =                            \
+			isc__nm_get_netievent(nm, netievent_##type);           \
+		isc__nmsocket_attach(sock, &ievent->sock);                     \
+		ievent->req = req;                                             \
+		ievent->result = result;                                       \
+                                                                               \
+		return (ievent);                                               \
+	}                                                                      \
+                                                                               \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                        \
+					  isc__netievent_##type##_t *ievent) { \
+		isc__nmsocket_detach(&ievent->sock);                           \
+		isc__nm_put_netievent(nm, ievent);                             \
+	}
+
+typedef struct isc__netievent__socket_handle {
+	NETIEVENT__SOCKET;
+	isc_nmhandle_t *handle;
+} isc__netievent__socket_handle_t;
+
+#define NETIEVENT_SOCKET_HANDLE_TYPE(type) \
+	typedef isc__netievent__socket_handle_t isc__netievent_##type##_t;
+
+#define NETIEVENT_SOCKET_HANDLE_DECL(type)                                   \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(             \
+		isc_nm_t *nm, isc_nmsocket_t *sock, isc_nmhandle_t *handle); \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                      \
+					  isc__netievent_##type##_t *ievent);
+
+#define NETIEVENT_SOCKET_HANDLE_DEF(type)                                      \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(               \
+		isc_nm_t *nm, isc_nmsocket_t *sock, isc_nmhandle_t *handle) {  \
+		isc__netievent_##type##_t *ievent =                            \
+			isc__nm_get_netievent(nm, netievent_##type);           \
+		isc__nmsocket_attach(sock, &ievent->sock);                     \
+		isc_nmhandle_attach(handle, &ievent->handle);                  \
+                                                                               \
+		return (ievent);                                               \
+	}                                                                      \
+                                                                               \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                        \
+					  isc__netievent_##type##_t *ievent) { \
+		isc__nmsocket_detach(&ievent->sock);                           \
+		isc_nmhandle_detach(&ievent->handle);                          \
+		isc__nm_put_netievent(nm, ievent);                             \
+	}
+
+typedef struct isc__netievent__socket_quota {
+	NETIEVENT__SOCKET;
+	isc_quota_t *quota;
+} isc__netievent__socket_quota_t;
+
+#define NETIEVENT_SOCKET_QUOTA_TYPE(type) \
+	typedef isc__netievent__socket_quota_t isc__netievent_##type##_t;
+
+#define NETIEVENT_SOCKET_QUOTA_DECL(type)                                \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(         \
+		isc_nm_t *nm, isc_nmsocket_t *sock, isc_quota_t *quota); \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                  \
+					  isc__netievent_##type##_t *ievent);
+
+#define NETIEVENT_SOCKET_QUOTA_DEF(type)                                       \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(               \
+		isc_nm_t *nm, isc_nmsocket_t *sock, isc_quota_t *quota) {      \
+		isc__netievent_##type##_t *ievent =                            \
+			isc__nm_get_netievent(nm, netievent_##type);           \
+		isc__nmsocket_attach(sock, &ievent->sock);                     \
+		ievent->quota = quota;                                         \
+                                                                               \
+		return (ievent);                                               \
+	}                                                                      \
+                                                                               \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                        \
+					  isc__netievent_##type##_t *ievent) { \
+		isc__nmsocket_detach(&ievent->sock);                           \
+		isc__nm_put_netievent(nm, ievent);                             \
+	}
+
+typedef struct isc__netievent__task {
+	isc__netievent_type type;
+	ISC_LINK(isc__netievent_t) link;
+	isc_task_t *task;
+} isc__netievent__task_t;
+
+#define NETIEVENT_TASK_TYPE(type) \
+	typedef isc__netievent__task_t isc__netievent_##type##_t;
+
+#define NETIEVENT_TASK_DECL(type)                                \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type( \
+		isc_nm_t *nm, isc_task_t *task);                 \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,          \
+					  isc__netievent_##type##_t *ievent);
+
+#define NETIEVENT_TASK_DEF(type)                                               \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(               \
+		isc_nm_t *nm, isc_task_t *task) {                              \
+		isc__netievent_##type##_t *ievent =                            \
+			isc__nm_get_netievent(nm, netievent_##type);           \
+		ievent->task = task;                                           \
+                                                                               \
+		return (ievent);                                               \
+	}                                                                      \
+                                                                               \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                        \
+					  isc__netievent_##type##_t *ievent) { \
+		ievent->task = NULL;                                           \
+		isc__nm_put_netievent(nm, ievent);                             \
+	}
+
+typedef struct isc__netievent_udpsend {
+	NETIEVENT__SOCKET;
+	isc_sockaddr_t peer;
+	isc__nm_uvreq_t *req;
+} isc__netievent_udpsend_t;
+
+typedef struct isc__netievent {
+	isc__netievent_type type;
+	ISC_LINK(isc__netievent_t) link;
+} isc__netievent_t;
+
+#define NETIEVENT_TYPE(type) typedef isc__netievent_t isc__netievent_##type##_t;
+
+#define NETIEVENT_DECL(type)                                                   \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(isc_nm_t *nm); \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                        \
+					  isc__netievent_##type##_t *ievent);
+
+#define NETIEVENT_DEF(type)                                                    \
+	isc__netievent_##type##_t *isc__nm_get_netievent_##type(               \
+		isc_nm_t *nm) {                                                \
+		isc__netievent_##type##_t *ievent =                            \
+			isc__nm_get_netievent(nm, netievent_##type);           \
+                                                                               \
+		return (ievent);                                               \
+	}                                                                      \
+                                                                               \
+	void isc__nm_put_netievent_##type(isc_nm_t *nm,                        \
+					  isc__netievent_##type##_t *ievent) { \
+		isc__nm_put_netievent(nm, ievent);                             \
+	}
+
+typedef union {
+	isc__netievent_t ni;
+	isc__netievent__socket_t nis;
+	isc__netievent__socket_req_t nisr;
+	isc__netievent_udpsend_t nius;
+	isc__netievent__socket_quota_t nisq;
+} isc__netievent_storage_t;
+
+/*
+ * Work item for a uv_work threadpool.
+ */
+typedef struct isc__nm_work {
+	isc_nm_t *netmgr;
+	uv_work_t req;
+	isc_nm_workcb_t cb;
+	isc_nm_after_workcb_t after_cb;
+	void *data;
+} isc__nm_work_t;
+
+/*
+ * Network manager
+ */
+#define NM_MAGIC    ISC_MAGIC('N', 'E', 'T', 'M')
+#define VALID_NM(t) ISC_MAGIC_VALID(t, NM_MAGIC)
+
+struct isc_nm {
+	int magic;
+	isc_refcount_t references;
+	isc_mem_t *mctx;
+	int nworkers;
+	isc_mutex_t lock;
+	isc_condition_t wkstatecond;
+	isc_condition_t wkpausecond;
+	isc__networker_t *workers;
+
+	isc_stats_t *stats;
+
+	uint_fast32_t workers_running;
+	atomic_uint_fast32_t workers_paused;
+	atomic_uint_fast32_t maxudp;
+
+	bool load_balance_sockets;
+
+	atomic_bool paused;
+
+	/*
+	 * Active connections are being closed and new connections are
+	 * no longer allowed.
+	 */
+	atomic_bool closing;
+
+	/*
+	 * A worker is actively waiting for other workers, for example to
+	 * stop listening; that means no other thread can do the same thing
+	 * or pause, or we'll deadlock. We have to either re-enqueue our
+	 * event or wait for the other one to finish if we want to pause.
+	 */
+	atomic_int interlocked;
+
+	/*
+	 * Timeout values for TCP connections, corresponding to
+	 * tcp-intiial-timeout, tcp-idle-timeout, tcp-keepalive-timeout,
+	 * and tcp-advertised-timeout. Note that these are stored in
+	 * milliseconds so they can be used directly with the libuv timer,
+	 * but they are configured in tenths of seconds.
+	 */
+	atomic_uint_fast32_t init;
+	atomic_uint_fast32_t idle;
+	atomic_uint_fast32_t keepalive;
+	atomic_uint_fast32_t advertised;
+
+	isc_barrier_t pausing;
+	isc_barrier_t resuming;
+
+#ifdef NETMGR_TRACE
+	ISC_LIST(isc_nmsocket_t) active_sockets;
+#endif
+};
+
+typedef enum isc_nmsocket_type {
+	isc_nm_udpsocket,
+	isc_nm_udplistener, /* Aggregate of nm_udpsocks */
+	isc_nm_tcpsocket,
+	isc_nm_tcplistener,
+	isc_nm_tcpdnslistener,
+	isc_nm_tcpdnssocket,
+} isc_nmsocket_type;
+
+/*%
+ * A universal structure for either a single socket or a group of
+ * dup'd/SO_REUSE_PORT-using sockets listening on the same interface.
+ */
+#define NMSOCK_MAGIC	ISC_MAGIC('N', 'M', 'S', 'K')
+#define VALID_NMSOCK(t) ISC_MAGIC_VALID(t, NMSOCK_MAGIC)
+
+/*%
+ * Index into socket stat counter arrays.
+ */
+enum {
+	STATID_OPEN = 0,
+	STATID_OPENFAIL = 1,
+	STATID_CLOSE = 2,
+	STATID_BINDFAIL = 3,
+	STATID_CONNECTFAIL = 4,
+	STATID_CONNECT = 5,
+	STATID_ACCEPTFAIL = 6,
+	STATID_ACCEPT = 7,
+	STATID_SENDFAIL = 8,
+	STATID_RECVFAIL = 9,
+	STATID_ACTIVE = 10
+};
+
+typedef void (*isc_nm_closehandlecb_t)(void *arg);
+/*%<
+ * Opaque callback function, used for isc_nmhandle 'reset' and 'free'
+ * callbacks.
+ */
+
+struct isc_nmsocket {
+	/*% Unlocked, RO */
+	int magic;
+	int tid;
+	isc_nmsocket_type type;
+	isc_nm_t *mgr;
+
+	/*% Parent socket for multithreaded listeners */
+	isc_nmsocket_t *parent;
+	/*% Listener socket this connection was accepted on */
+	isc_nmsocket_t *listener;
+	/*% Self socket */
+	isc_nmsocket_t *self;
+
+	isc_barrier_t startlistening;
+	isc_barrier_t stoplistening;
+
+	/*%
+	 * quota is the TCP client, attached when a TCP connection
+	 * is established. pquota is a non-attached pointer to the
+	 * TCP client quota, stored in listening sockets but only
+	 * attached in connected sockets.
+	 */
+	isc_quota_t *quota;
+	isc_quota_t *pquota;
+	isc_quota_cb_t quotacb;
+
+	/*%
+	 * Socket statistics
+	 */
+	const isc_statscounter_t *statsindex;
+
+	/*%
+	 * TCP read/connect timeout timers.
+	 */
+	uv_timer_t read_timer;
+	uint64_t read_timeout;
+	uint64_t connect_timeout;
+
+	/*%
+	 * TCP write timeout timer.
+	 */
+	uint64_t write_timeout;
+
+	/*% outer socket is for 'wrapped' sockets - e.g. tcpdns in tcp */
+	isc_nmsocket_t *outer;
+
+	/*% server socket for connections */
+	isc_nmsocket_t *server;
+
+	/*% Child sockets for multi-socket setups */
+	isc_nmsocket_t *children;
+	uint_fast32_t nchildren;
+	isc_sockaddr_t iface;
+	isc_nmhandle_t *statichandle;
+	isc_nmhandle_t *outerhandle;
+
+	/*% Extra data allocated at the end of each isc_nmhandle_t */
+	size_t extrahandlesize;
+
+	/*% TCP backlog */
+	int backlog;
+
+	/*% libuv data */
+	uv_os_sock_t fd;
+	union uv_any_handle uv_handle;
+
+	/*% Peer address */
+	isc_sockaddr_t peer;
+
+	/* Atomic */
+	/*% Number of running (e.g. listening) child sockets */
+	atomic_uint_fast32_t rchildren;
+
+	/*%
+	 * Socket is active if it's listening, working, etc. If it's
+	 * closing, then it doesn't make a sense, for example, to
+	 * push handles or reqs for reuse.
+	 */
+	atomic_bool active;
+	atomic_bool destroying;
+
+	/*%
+	 * Socket is closed if it's not active and all the possible
+	 * callbacks were fired, there are no active handles, etc.
+	 * If active==false but closed==false, that means the socket
+	 * is closing.
+	 */
+	atomic_bool closing;
+	atomic_bool closed;
+	atomic_bool listening;
+	atomic_bool connecting;
+	atomic_bool connected;
+	bool accepting;
+	bool reading;
+	atomic_bool timedout;
+	isc_refcount_t references;
+
+	/*%
+	 * Established an outgoing connection, as client not server.
+	 */
+	atomic_bool client;
+
+	/*%
+	 * TCPDNS socket has been set not to pipeline.
+	 */
+	atomic_bool sequential;
+
+	/*%
+	 * The socket is processing read callback, this is guard to not read
+	 * data before the readcb is back.
+	 */
+	bool processing;
+
+	/*%
+	 * A TCP socket has had isc_nm_pauseread() called.
+	 */
+	atomic_bool readpaused;
+
+	/*%
+	 * A TCP or TCPDNS socket has been set to use the keepalive
+	 * timeout instead of the default idle timeout.
+	 */
+	atomic_bool keepalive;
+
+	/*%
+	 * 'spare' handles for that can be reused to avoid allocations,
+	 * for UDP.
+	 */
+	isc_astack_t *inactivehandles;
+	isc_astack_t *inactivereqs;
+
+	/*%
+	 * Used to wait for TCP listening events to complete, and
+	 * for the number of running children to reach zero during
+	 * shutdown.
+	 *
+	 * We use two condition variables to prevent the race where the netmgr
+	 * threads would be able to finish and destroy the socket before it's
+	 * unlocked by the isc_nm_listen<proto>() function.  So, the flow is as
+	 * follows:
+	 *
+	 *   1. parent thread creates all children sockets and passes then to
+	 *      netthreads, looks at the signaling variable and WAIT(cond) until
+	 *      the childrens are done initializing
+	 *
+	 *   2. the events get picked by netthreads, calls the libuv API (and
+	 *      either succeeds or fails) and WAIT(scond) until all other
+	 *      children sockets in netthreads are initialized and the listening
+	 *      socket lock is unlocked
+	 *
+	 *   3. the control is given back to the parent thread which now either
+	 *      returns success or shutdowns the listener if an error has
+	 *      occured in the children netthread
+	 *
+	 * NOTE: The other approach would be doing an extra attach to the parent
+	 * listening socket, and then detach it in the parent thread, but that
+	 * breaks the promise that once the libuv socket is initialized on the
+	 * nmsocket, the nmsocket needs to be handled only by matching
+	 * netthread, so in fact that would add a complexity in a way that
+	 * isc__nmsocket_detach would have to be converted to use an
+	 * asynchrounous netievent.
+	 */
+	isc_mutex_t lock;
+	isc_condition_t cond;
+	isc_condition_t scond;
+
+	/*%
+	 * Used to pass a result back from listen or connect events.
+	 */
+	isc_result_t result;
+
+	/*%
+	 * Current number of active handles.
+	 */
+	atomic_int_fast32_t ah;
+
+	/*% Buffer for TCPDNS processing */
+	size_t buf_size;
+	size_t buf_len;
+	unsigned char *buf;
+
+	/*%
+	 * This function will be called with handle->sock
+	 * as the argument whenever a handle's references drop
+	 * to zero, after its reset callback has been called.
+	 */
+	isc_nm_closehandlecb_t closehandle_cb;
+
+	isc_nmhandle_t *recv_handle;
+	isc_nm_recv_cb_t recv_cb;
+	void *recv_cbarg;
+	bool recv_read;
+
+	isc_nm_cb_t connect_cb;
+	void *connect_cbarg;
+
+	isc_nm_accept_cb_t accept_cb;
+	void *accept_cbarg;
+
+	atomic_int_fast32_t active_child_connections;
+
+#ifdef NETMGR_TRACE
+	void *backtrace[TRACE_SIZE];
+	int backtrace_size;
+	LINK(isc_nmsocket_t) active_link;
+	ISC_LIST(isc_nmhandle_t) active_handles;
+#endif
+};
+
+bool
+isc__nm_in_netthread(void);
+/*%
+ * Returns 'true' if we're in the network thread.
+ */
+
+void
+isc__nm_maybe_enqueue_ievent(isc__networker_t *worker, isc__netievent_t *event);
+/*%<
+ * If the caller is already in the matching nmthread, process the netievent
+ * directly, if not enqueue using isc__nm_enqueue_ievent().
+ */
+
+void
+isc__nm_enqueue_ievent(isc__networker_t *worker, isc__netievent_t *event);
+/*%<
+ * Enqueue an ievent onto a specific worker queue. (This the only safe
+ * way to use an isc__networker_t from another thread.)
+ */
+
+void
+isc__nm_free_uvbuf(isc_nmsocket_t *sock, const uv_buf_t *buf);
+/*%<
+ * Free a buffer allocated for a receive operation.
+ *
+ * Note that as currently implemented, this doesn't actually
+ * free anything, marks the isc__networker's UDP receive buffer
+ * as "not in use".
+ */
+
+isc_nmhandle_t *
+isc___nmhandle_get(isc_nmsocket_t *sock, isc_sockaddr_t *peer,
+		   isc_sockaddr_t *local FLARG);
+/*%<
+ * Get a handle for the socket 'sock', allocating a new one
+ * if there isn't one available in 'sock->inactivehandles'.
+ *
+ * If 'peer' is not NULL, set the handle's peer address to 'peer',
+ * otherwise set it to 'sock->peer'.
+ *
+ * If 'local' is not NULL, set the handle's local address to 'local',
+ * otherwise set it to 'sock->iface->addr'.
+ *
+ * 'sock' will be attached to 'handle->sock'. The caller may need
+ * to detach the socket afterward.
+ */
+
+isc__nm_uvreq_t *
+isc___nm_uvreq_get(isc_nm_t *mgr, isc_nmsocket_t *sock FLARG);
+/*%<
+ * Get a UV request structure for the socket 'sock', allocating a
+ * new one if there isn't one available in 'sock->inactivereqs'.
+ */
+
+void
+isc___nm_uvreq_put(isc__nm_uvreq_t **req, isc_nmsocket_t *sock FLARG);
+/*%<
+ * Completes the use of a UV request structure, setting '*req' to NULL.
+ *
+ * The UV request is pushed onto the 'sock->inactivereqs' stack or,
+ * if that doesn't work, freed.
+ */
+
+void
+isc___nmsocket_init(isc_nmsocket_t *sock, isc_nm_t *mgr, isc_nmsocket_type type,
+		    isc_sockaddr_t *iface FLARG);
+/*%<
+ * Initialize socket 'sock', attach it to 'mgr', and set it to type 'type'
+ * and its interface to 'iface'.
+ */
+
+void
+isc___nmsocket_attach(isc_nmsocket_t *sock, isc_nmsocket_t **target FLARG);
+/*%<
+ * Attach to a socket, increasing refcount
+ */
+
+void
+isc___nmsocket_detach(isc_nmsocket_t **socketp FLARG);
+/*%<
+ * Detach from socket, decreasing refcount and possibly destroying the
+ * socket if it's no longer referenced.
+ */
+
+void
+isc___nmsocket_prep_destroy(isc_nmsocket_t *sock FLARG);
+/*%<
+ * Market 'sock' as inactive, close it if necessary, and destroy it
+ * if there are no remaining references or active handles.
+ */
+
+void
+isc__nmsocket_shutdown(isc_nmsocket_t *sock);
+/*%<
+ * Initiate the socket shutdown which actively calls the active
+ * callbacks.
+ */
+
+bool
+isc__nmsocket_active(isc_nmsocket_t *sock);
+/*%<
+ * Determine whether 'sock' is active by checking 'sock->active'
+ * or, for child sockets, 'sock->parent->active'.
+ */
+
+bool
+isc__nmsocket_deactivate(isc_nmsocket_t *sock);
+/*%<
+ * @brief Deactivate active socket
+ *
+ * Atomically deactive the socket by setting @p sock->active or, for child
+ * sockets, @p sock->parent->active to @c false
+ *
+ * @param[in] sock - valid nmsocket
+ * @return @c false if the socket was already inactive, @c true otherwise
+ */
+
+void
+isc__nmsocket_clearcb(isc_nmsocket_t *sock);
+/*%<
+ * Clear the recv and accept callbacks in 'sock'.
+ */
+
+void
+isc__nmsocket_timer_stop(isc_nmsocket_t *sock);
+void
+isc__nmsocket_timer_start(isc_nmsocket_t *sock);
+void
+isc__nmsocket_timer_restart(isc_nmsocket_t *sock);
+bool
+isc__nmsocket_timer_running(isc_nmsocket_t *sock);
+/*%<
+ * Start/stop/restart/check the timeout on the socket
+ */
+
+void
+isc__nm_connectcb(isc_nmsocket_t *sock, isc__nm_uvreq_t *uvreq,
+		  isc_result_t eresult, bool async);
+
+void
+isc__nm_async_connectcb(isc__networker_t *worker, isc__netievent_t *ev0);
+/*%<
+ * Issue a connect callback on the socket, used to call the callback
+ */
+
+void
+isc__nm_readcb(isc_nmsocket_t *sock, isc__nm_uvreq_t *uvreq,
+	       isc_result_t eresult);
+void
+isc__nm_async_readcb(isc__networker_t *worker, isc__netievent_t *ev0);
+
+/*%<
+ * Issue a read callback on the socket, used to call the callback
+ * on failed conditions when the event can't be scheduled on the uv loop.
+ *
+ */
+
+void
+isc__nm_sendcb(isc_nmsocket_t *sock, isc__nm_uvreq_t *uvreq,
+	       isc_result_t eresult, bool async);
+void
+isc__nm_async_sendcb(isc__networker_t *worker, isc__netievent_t *ev0);
+/*%<
+ * Issue a write callback on the socket, used to call the callback
+ * on failed conditions when the event can't be scheduled on the uv loop.
+ */
+
+void
+isc__nm_async_shutdown(isc__networker_t *worker, isc__netievent_t *ev0);
+/*%<
+ * Walk through all uv handles, get the underlying sockets and issue
+ * close on them.
+ */
+
+void
+isc__nm_udp_send(isc_nmhandle_t *handle, const isc_region_t *region,
+		 isc_nm_cb_t cb, void *cbarg);
+/*%<
+ * Back-end implementation of isc_nm_send() for UDP handles.
+ */
+
+void
+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_cancelread(isc_nmhandle_t *handle);
+/*%<
+ * Stop reading on a connected UDP handle.
+ */
+
+void
+isc__nm_udp_shutdown(isc_nmsocket_t *sock);
+/*%<
+ * Called during the shutdown process to close and clean up connected
+ * sockets.
+ */
+
+void
+isc__nm_udp_stoplistening(isc_nmsocket_t *sock);
+/*%<
+ * Stop listening on 'sock'.
+ */
+
+void
+isc__nm_udp_settimeout(isc_nmhandle_t *handle, uint32_t timeout);
+/*%<
+ * Set or clear the recv timeout for the UDP socket associated with 'handle'.
+ */
+
+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_udpcancel(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).
+ */
+
+void
+isc__nm_tcp_send(isc_nmhandle_t *handle, const isc_region_t *region,
+		 isc_nm_cb_t cb, void *cbarg);
+/*%<
+ * Back-end implementation of isc_nm_send() for TCP handles.
+ */
+
+void
+isc__nm_tcp_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg);
+/*
+ * Back-end implementation of isc_nm_read() for TCP handles.
+ */
+
+void
+isc__nm_tcp_close(isc_nmsocket_t *sock);
+/*%<
+ * Close a TCP socket.
+ */
+void
+isc__nm_tcp_pauseread(isc_nmhandle_t *handle);
+/*%<
+ * Pause reading on this handle, while still remembering the callback.
+ */
+
+void
+isc__nm_tcp_resumeread(isc_nmhandle_t *handle);
+/*%<
+ * Resume reading from socket.
+ *
+ */
+
+void
+isc__nm_tcp_shutdown(isc_nmsocket_t *sock);
+/*%<
+ * Called during the shutdown process to close and clean up connected
+ * sockets.
+ */
+
+void
+isc__nm_tcp_cancelread(isc_nmhandle_t *handle);
+/*%<
+ * Stop reading on a connected TCP handle.
+ */
+
+void
+isc__nm_tcp_stoplistening(isc_nmsocket_t *sock);
+/*%<
+ * Stop listening on 'sock'.
+ */
+
+int_fast32_t
+isc__nm_tcp_listener_nactive(isc_nmsocket_t *sock);
+/*%<
+ * Returns the number of active connections for the TCP listener socket.
+ */
+
+void
+isc__nm_tcp_settimeout(isc_nmhandle_t *handle, uint32_t timeout);
+/*%<
+ * Set the read timeout for the TCP socket associated with 'handle'.
+ */
+
+void
+isc__nm_async_tcpconnect(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcplisten(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpaccept(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpstop(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpsend(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_startread(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_pauseread(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpstartread(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcppauseread(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpcancel(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpclose(isc__networker_t *worker, isc__netievent_t *ev0);
+/*%<
+ * Callback handlers for asynchronous TCP events (connect, listen,
+ * stoplisten, send, read, pause, close).
+ */
+
+void
+isc__nm_async_tcpdnsaccept(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpdnsconnect(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpdnslisten(isc__networker_t *worker, isc__netievent_t *ev0);
+
+void
+isc__nm_tcpdns_send(isc_nmhandle_t *handle, isc_region_t *region,
+		    isc_nm_cb_t cb, void *cbarg);
+/*%<
+ * Back-end implementation of isc_nm_send() for TCPDNS handles.
+ */
+
+void
+isc__nm_tcpdns_shutdown(isc_nmsocket_t *sock);
+
+void
+isc__nm_tcpdns_close(isc_nmsocket_t *sock);
+/*%<
+ * Close a TCPDNS socket.
+ */
+
+void
+isc__nm_tcpdns_stoplistening(isc_nmsocket_t *sock);
+/*%<
+ * Stop listening on 'sock'.
+ */
+
+void
+isc__nm_tcpdns_settimeout(isc_nmhandle_t *handle, uint32_t timeout);
+/*%<
+ * Set the read timeout and reset the timer for the TCPDNS socket
+ * associated with 'handle', and the TCP socket it wraps around.
+ */
+
+void
+isc__nm_async_tcpdnsaccept(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpdnsconnect(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpdnslisten(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpdnscancel(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+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_tcpdnsstop(isc__networker_t *worker, isc__netievent_t *ev0);
+void
+isc__nm_async_tcpdnsread(isc__networker_t *worker, isc__netievent_t *ev0);
+/*%<
+ * Callback handlers for asynchronous TCPDNS events.
+ */
+
+void
+isc__nm_tcpdns_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg);
+/*
+ * Back-end implementation of isc_nm_read() for TCPDNS handles.
+ */
+
+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__, __func__)
+isc_result_t
+isc___nm_uverr2result(int uverr, bool dolog, const char *file,
+		      unsigned int line, const char *func);
+/*%<
+ * Convert a libuv error value into an isc_result_t.  The
+ * list of supported error values is not complete; new users
+ * of this function should add any expected errors that are
+ * not already there.
+ */
+
+bool
+isc__nm_acquire_interlocked(isc_nm_t *mgr);
+/*%<
+ * Try to acquire interlocked state; return true if successful.
+ */
+
+void
+isc__nm_drop_interlocked(isc_nm_t *mgr);
+/*%<
+ * Drop interlocked state; signal waiters.
+ */
+
+void
+isc__nm_acquire_interlocked_force(isc_nm_t *mgr);
+/*%<
+ * Actively wait for interlocked state.
+ */
+
+void
+isc__nm_incstats(isc_nm_t *mgr, isc_statscounter_t counterid);
+/*%<
+ * Increment socket-related statistics counters.
+ */
+
+void
+isc__nm_decstats(isc_nm_t *mgr, isc_statscounter_t counterid);
+/*%<
+ * Decrement socket-related statistics counters.
+ */
+
+isc_result_t
+isc__nm_socket(int domain, int type, int protocol, uv_os_sock_t *sockp);
+/*%<
+ * Platform independent socket() version
+ */
+
+void
+isc__nm_closesocket(uv_os_sock_t sock);
+/*%<
+ * Platform independent closesocket() version
+ */
+
+isc_result_t
+isc__nm_socket_freebind(uv_os_sock_t fd, sa_family_t sa_family);
+/*%<
+ * Set the IP_FREEBIND (or equivalent) socket option on the uv_handle
+ */
+
+isc_result_t
+isc__nm_socket_reuse(uv_os_sock_t fd);
+/*%<
+ * Set the SO_REUSEADDR or SO_REUSEPORT (or equivalent) socket option on the fd
+ */
+
+isc_result_t
+isc__nm_socket_reuse_lb(uv_os_sock_t fd);
+/*%<
+ * Set the SO_REUSEPORT_LB (or equivalent) socket option on the fd
+ */
+
+isc_result_t
+isc__nm_socket_incoming_cpu(uv_os_sock_t fd);
+/*%<
+ * Set the SO_INCOMING_CPU socket option on the fd if available
+ */
+
+isc_result_t
+isc__nm_socket_disable_pmtud(uv_os_sock_t fd, sa_family_t sa_family);
+/*%<
+ * Disable the Path MTU Discovery, either by disabling IP(V6)_DONTFRAG socket
+ * option, or setting the IP(V6)_MTU_DISCOVER socket option to IP_PMTUDISC_OMIT
+ */
+
+isc_result_t
+isc__nm_socket_connectiontimeout(uv_os_sock_t fd, int timeout_ms);
+/*%<
+ * Set the connection timeout in milliseconds, on non-Linux platforms,
+ * the minimum value must be at least 1000 (1 second).
+ */
+
+isc_result_t
+isc__nm_socket_tcp_nodelay(uv_os_sock_t fd);
+/*%<
+ * Disables Nagle's algorithm on a TCP socket (sets TCP_NODELAY).
+ */
+
+/*
+ * typedef all the netievent types
+ */
+
+NETIEVENT_SOCKET_TYPE(close);
+NETIEVENT_SOCKET_TYPE(tcpclose);
+NETIEVENT_SOCKET_TYPE(tcplisten);
+NETIEVENT_SOCKET_TYPE(tcppauseread);
+NETIEVENT_SOCKET_TYPE(tcpstop);
+NETIEVENT_SOCKET_TYPE(udpclose);
+NETIEVENT_SOCKET_TYPE(udplisten);
+NETIEVENT_SOCKET_TYPE(udpread);
+/* NETIEVENT_SOCKET_TYPE(udpsend); */ /* unique type, defined independently */
+NETIEVENT_SOCKET_TYPE(udpstop);
+
+NETIEVENT_SOCKET_TYPE(tcpdnsclose);
+NETIEVENT_SOCKET_TYPE(tcpdnsread);
+NETIEVENT_SOCKET_TYPE(tcpdnsstop);
+NETIEVENT_SOCKET_TYPE(tcpdnslisten);
+NETIEVENT_SOCKET_REQ_TYPE(tcpdnsconnect);
+NETIEVENT_SOCKET_REQ_TYPE(tcpdnssend);
+NETIEVENT_SOCKET_HANDLE_TYPE(tcpdnscancel);
+NETIEVENT_SOCKET_QUOTA_TYPE(tcpdnsaccept);
+
+NETIEVENT_SOCKET_REQ_TYPE(tcpconnect);
+NETIEVENT_SOCKET_REQ_TYPE(tcpsend);
+NETIEVENT_SOCKET_TYPE(tcpstartread);
+NETIEVENT_SOCKET_REQ_TYPE(udpconnect);
+
+NETIEVENT_SOCKET_REQ_RESULT_TYPE(connectcb);
+NETIEVENT_SOCKET_REQ_RESULT_TYPE(readcb);
+NETIEVENT_SOCKET_REQ_RESULT_TYPE(sendcb);
+
+NETIEVENT_SOCKET_HANDLE_TYPE(detach);
+NETIEVENT_SOCKET_HANDLE_TYPE(tcpcancel);
+NETIEVENT_SOCKET_HANDLE_TYPE(udpcancel);
+
+NETIEVENT_SOCKET_QUOTA_TYPE(tcpaccept);
+
+NETIEVENT_TYPE(pause);
+NETIEVENT_TYPE(resume);
+NETIEVENT_TYPE(shutdown);
+NETIEVENT_TYPE(stop);
+
+NETIEVENT_TASK_TYPE(task);
+NETIEVENT_TASK_TYPE(privilegedtask);
+
+/* Now declared the helper functions */
+
+NETIEVENT_SOCKET_DECL(close);
+NETIEVENT_SOCKET_DECL(tcpclose);
+NETIEVENT_SOCKET_DECL(tcplisten);
+NETIEVENT_SOCKET_DECL(tcppauseread);
+NETIEVENT_SOCKET_DECL(tcpstartread);
+NETIEVENT_SOCKET_DECL(tcpstop);
+NETIEVENT_SOCKET_DECL(udpclose);
+NETIEVENT_SOCKET_DECL(udplisten);
+NETIEVENT_SOCKET_DECL(udpread);
+NETIEVENT_SOCKET_DECL(udpsend);
+NETIEVENT_SOCKET_DECL(udpstop);
+
+NETIEVENT_SOCKET_DECL(tcpdnsclose);
+NETIEVENT_SOCKET_DECL(tcpdnsread);
+NETIEVENT_SOCKET_DECL(tcpdnsstop);
+NETIEVENT_SOCKET_DECL(tcpdnslisten);
+NETIEVENT_SOCKET_REQ_DECL(tcpdnsconnect);
+NETIEVENT_SOCKET_REQ_DECL(tcpdnssend);
+NETIEVENT_SOCKET_HANDLE_DECL(tcpdnscancel);
+NETIEVENT_SOCKET_QUOTA_DECL(tcpdnsaccept);
+
+NETIEVENT_SOCKET_REQ_DECL(tcpconnect);
+NETIEVENT_SOCKET_REQ_DECL(tcpsend);
+NETIEVENT_SOCKET_REQ_DECL(udpconnect);
+
+NETIEVENT_SOCKET_REQ_RESULT_DECL(connectcb);
+NETIEVENT_SOCKET_REQ_RESULT_DECL(readcb);
+NETIEVENT_SOCKET_REQ_RESULT_DECL(sendcb);
+
+NETIEVENT_SOCKET_HANDLE_DECL(udpcancel);
+NETIEVENT_SOCKET_HANDLE_DECL(tcpcancel);
+NETIEVENT_SOCKET_DECL(detach);
+
+NETIEVENT_SOCKET_QUOTA_DECL(tcpaccept);
+
+NETIEVENT_DECL(pause);
+NETIEVENT_DECL(resume);
+NETIEVENT_DECL(shutdown);
+NETIEVENT_DECL(stop);
+
+NETIEVENT_TASK_DECL(task);
+NETIEVENT_TASK_DECL(privilegedtask);
+
+void
+isc__nm_udp_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result);
+void
+isc__nm_tcp_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result);
+void
+isc__nm_tcpdns_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result);
+
+isc_result_t
+isc__nm_tcpdns_processbuffer(isc_nmsocket_t *sock);
+
+isc__nm_uvreq_t *
+isc__nm_get_read_req(isc_nmsocket_t *sock, isc_sockaddr_t *sockaddr);
+
+void
+isc__nm_alloc_cb(uv_handle_t *handle, size_t size, uv_buf_t *buf);
+
+void
+isc__nm_udp_read_cb(uv_udp_t *handle, ssize_t nrecv, const uv_buf_t *buf,
+		    const struct sockaddr *addr, unsigned flags);
+void
+isc__nm_tcp_read_cb(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf);
+void
+isc__nm_tcpdns_read_cb(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf);
+
+isc_result_t
+isc__nm_start_reading(isc_nmsocket_t *sock);
+void
+isc__nm_stop_reading(isc_nmsocket_t *sock);
+isc_result_t
+isc__nm_process_sock_buffer(isc_nmsocket_t *sock);
+void
+isc__nm_resume_processing(void *arg);
+bool
+isc__nmsocket_closing(isc_nmsocket_t *sock);
+bool
+isc__nm_closing(isc_nmsocket_t *sock);
+
+void
+isc__nm_alloc_dnsbuf(isc_nmsocket_t *sock, size_t len);
+
+void
+isc__nm_failed_send_cb(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
+		       isc_result_t eresult);
+void
+isc__nm_failed_accept_cb(isc_nmsocket_t *sock, isc_result_t eresult);
+void
+isc__nm_failed_connect_cb(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
+			  isc_result_t eresult, bool async);
+void
+isc__nm_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result, bool async);
+
+void
+isc__nm_accept_connection_log(isc_result_t result, bool can_log_quota);
+
+/*
+ * Timeout callbacks
+ */
+void
+isc__nmsocket_connecttimeout_cb(uv_timer_t *timer);
+void
+isc__nmsocket_readtimeout_cb(uv_timer_t *timer);
+void
+isc__nmsocket_writetimeout_cb(void *data, isc_result_t eresult);
+
+/*%<
+ *
+ * Maximum number of simultaneous handles in flight supported for a single
+ * connected TCPDNS socket. This value was chosen arbitrarily, and may be
+ * changed in the future.
+ */
+#define STREAM_CLIENTS_PER_CONN 23
+
+#define UV_RUNTIME_CHECK(func, ret)                                           \
+	if (ret != 0) {                                                       \
+		isc_error_fatal(__FILE__, __LINE__, "%s failed: %s\n", #func, \
+				uv_strerror(ret));                            \
+	}
diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
new file mode 100644
index 0000000..6f42ec9
--- /dev/null
+++ b/lib/isc/netmgr/netmgr.c
@@ -0,0 +1,3396 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <inttypes.h>
+#include <unistd.h>
+#include <uv.h>
+#ifdef HAVE_LIBCTRACE
+#include <execinfo.h>
+#endif /* ifdef HAVE_LIBCTRACE */
+
+#include <isc/atomic.h>
+#include <isc/barrier.h>
+#include <isc/buffer.h>
+#include <isc/condition.h>
+#include <isc/errno.h>
+#include <isc/list.h>
+#include <isc/log.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/netmgr.h>
+#include <isc/print.h>
+#include <isc/quota.h>
+#include <isc/random.h>
+#include <isc/refcount.h>
+#include <isc/region.h>
+#include <isc/result.h>
+#include <isc/sockaddr.h>
+#include <isc/stats.h>
+#include <isc/strerr.h>
+#include <isc/task.h>
+#include <isc/thread.h>
+#include <isc/util.h>
+
+#include "netmgr-int.h"
+#include "netmgr_p.h"
+#include "openssl_shim.h"
+#include "trampoline_p.h"
+#include "uv-compat.h"
+
+/*%
+ * How many isc_nmhandles and isc_nm_uvreqs will we be
+ * caching for reuse in a socket.
+ */
+#define ISC_NM_HANDLES_STACK_SIZE 600
+#define ISC_NM_REQS_STACK_SIZE	  600
+
+/*%
+ * Shortcut index arrays to get access to statistics counters.
+ */
+
+static const isc_statscounter_t udp4statsindex[] = {
+	isc_sockstatscounter_udp4open,
+	isc_sockstatscounter_udp4openfail,
+	isc_sockstatscounter_udp4close,
+	isc_sockstatscounter_udp4bindfail,
+	isc_sockstatscounter_udp4connectfail,
+	isc_sockstatscounter_udp4connect,
+	-1,
+	-1,
+	isc_sockstatscounter_udp4sendfail,
+	isc_sockstatscounter_udp4recvfail,
+	isc_sockstatscounter_udp4active
+};
+
+static const isc_statscounter_t udp6statsindex[] = {
+	isc_sockstatscounter_udp6open,
+	isc_sockstatscounter_udp6openfail,
+	isc_sockstatscounter_udp6close,
+	isc_sockstatscounter_udp6bindfail,
+	isc_sockstatscounter_udp6connectfail,
+	isc_sockstatscounter_udp6connect,
+	-1,
+	-1,
+	isc_sockstatscounter_udp6sendfail,
+	isc_sockstatscounter_udp6recvfail,
+	isc_sockstatscounter_udp6active
+};
+
+static const isc_statscounter_t tcp4statsindex[] = {
+	isc_sockstatscounter_tcp4open,	      isc_sockstatscounter_tcp4openfail,
+	isc_sockstatscounter_tcp4close,	      isc_sockstatscounter_tcp4bindfail,
+	isc_sockstatscounter_tcp4connectfail, isc_sockstatscounter_tcp4connect,
+	isc_sockstatscounter_tcp4acceptfail,  isc_sockstatscounter_tcp4accept,
+	isc_sockstatscounter_tcp4sendfail,    isc_sockstatscounter_tcp4recvfail,
+	isc_sockstatscounter_tcp4active
+};
+
+static const isc_statscounter_t tcp6statsindex[] = {
+	isc_sockstatscounter_tcp6open,	      isc_sockstatscounter_tcp6openfail,
+	isc_sockstatscounter_tcp6close,	      isc_sockstatscounter_tcp6bindfail,
+	isc_sockstatscounter_tcp6connectfail, isc_sockstatscounter_tcp6connect,
+	isc_sockstatscounter_tcp6acceptfail,  isc_sockstatscounter_tcp6accept,
+	isc_sockstatscounter_tcp6sendfail,    isc_sockstatscounter_tcp6recvfail,
+	isc_sockstatscounter_tcp6active
+};
+
+#if 0
+/* XXX: not currently used */
+static const isc_statscounter_t unixstatsindex[] = {
+	isc_sockstatscounter_unixopen,
+	isc_sockstatscounter_unixopenfail,
+	isc_sockstatscounter_unixclose,
+	isc_sockstatscounter_unixbindfail,
+	isc_sockstatscounter_unixconnectfail,
+	isc_sockstatscounter_unixconnect,
+	isc_sockstatscounter_unixacceptfail,
+	isc_sockstatscounter_unixaccept,
+	isc_sockstatscounter_unixsendfail,
+	isc_sockstatscounter_unixrecvfail,
+	isc_sockstatscounter_unixactive
+};
+#endif /* if 0 */
+
+/*
+ * libuv is not thread safe, but has mechanisms to pass messages
+ * between threads. Each socket is owned by a thread. For UDP
+ * sockets we have a set of sockets for each interface and we can
+ * choose a sibling and send the message directly. For TCP, or if
+ * we're calling from a non-networking thread, we need to pass the
+ * request using async_cb.
+ */
+
+#if defined(HAVE_THREAD_LOCAL)
+#include <threads.h>
+static thread_local int isc__nm_tid_v = ISC_NETMGR_TID_UNKNOWN;
+#elif defined(HAVE___THREAD)
+static __thread int isc__nm_tid_v = ISC_NETMGR_TID_UNKNOWN;
+#elif HAVE___DECLSPEC_THREAD
+__declspec(thread) int isc__nm_tid_v = ISC_NETMGR_TID_UNKNOWN;
+#endif /* if defined(HAVE_THREAD_LOCAL) */
+
+static void
+nmsocket_maybe_destroy(isc_nmsocket_t *sock FLARG);
+static void
+nmhandle_free(isc_nmsocket_t *sock, isc_nmhandle_t *handle);
+static isc_threadresult_t
+nm_thread(isc_threadarg_t worker0);
+static void
+async_cb(uv_async_t *handle);
+
+static bool
+process_netievent(isc__networker_t *worker, isc__netievent_t *ievent);
+static isc_result_t
+process_queue(isc__networker_t *worker, netievent_type_t type);
+static void
+wait_for_priority_queue(isc__networker_t *worker);
+static void
+drain_queue(isc__networker_t *worker, netievent_type_t type);
+
+static void
+isc__nm_async_stop(isc__networker_t *worker, isc__netievent_t *ev0);
+static void
+isc__nm_async_pause(isc__networker_t *worker, isc__netievent_t *ev0);
+static void
+isc__nm_async_resume(isc__networker_t *worker, isc__netievent_t *ev0);
+static void
+isc__nm_async_detach(isc__networker_t *worker, isc__netievent_t *ev0);
+static void
+isc__nm_async_close(isc__networker_t *worker, isc__netievent_t *ev0);
+
+static void
+isc__nm_threadpool_initialize(uint32_t workers);
+static void
+isc__nm_work_cb(uv_work_t *req);
+static void
+isc__nm_after_work_cb(uv_work_t *req, int status);
+
+void
+isc__nmsocket_reset(isc_nmsocket_t *sock);
+
+/*%<
+ * Issue a 'handle closed' callback on the socket.
+ */
+
+static void
+nmhandle_detach_cb(isc_nmhandle_t **handlep FLARG);
+
+int
+isc_nm_tid(void) {
+	return (isc__nm_tid_v);
+}
+
+bool
+isc__nm_in_netthread(void) {
+	return (isc__nm_tid_v >= 0);
+}
+
+#ifdef WIN32
+static void
+isc__nm_winsock_initialize(void) {
+	WORD wVersionRequested = MAKEWORD(2, 2);
+	WSADATA wsaData;
+	int result;
+
+	result = WSAStartup(wVersionRequested, &wsaData);
+	if (result != 0) {
+		char strbuf[ISC_STRERRORSIZE];
+		strerror_r(result, strbuf, sizeof(strbuf));
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "WSAStartup() failed with error code %lu: %s",
+				 result, strbuf);
+	}
+
+	/*
+	 * Confirm that the WinSock DLL supports version 2.2.  Note that if the
+	 * DLL supports versions greater than 2.2 in addition to 2.2, it will
+	 * still return 2.2 in wVersion since that is the version we requested.
+	 */
+	if (LOBYTE(wsaData.wVersion) != 2 || HIBYTE(wsaData.wVersion) != 2) {
+		UNEXPECTED_ERROR(__FILE__, __LINE__,
+				 "Unusable WinSock DLL version: %u.%u",
+				 LOBYTE(wsaData.wVersion),
+				 HIBYTE(wsaData.wVersion));
+	}
+}
+
+static void
+isc__nm_winsock_destroy(void) {
+	WSACleanup();
+}
+#endif /* WIN32 */
+
+static void
+isc__nm_threadpool_initialize(uint32_t workers) {
+	char buf[11];
+	int r = uv_os_getenv("UV_THREADPOOL_SIZE", buf,
+			     &(size_t){ sizeof(buf) });
+	if (r == UV_ENOENT) {
+		snprintf(buf, sizeof(buf), "%" PRIu32, workers);
+		uv_os_setenv("UV_THREADPOOL_SIZE", buf);
+	}
+}
+
+#if HAVE_DECL_UV_UDP_MMSG_FREE
+#define MINIMAL_UV_VERSION UV_VERSION(1, 40, 0)
+#elif HAVE_DECL_UV_UDP_RECVMMSG
+#define MAXIMAL_UV_VERSION UV_VERSION(1, 39, 99)
+#define MINIMAL_UV_VERSION UV_VERSION(1, 37, 0)
+#elif _WIN32
+#define MINIMAL_UV_VERSION UV_VERSION(1, 0, 0)
+#else
+#define MAXIMAL_UV_VERSION UV_VERSION(1, 34, 99)
+#define MINIMAL_UV_VERSION UV_VERSION(1, 0, 0)
+#endif
+
+void
+isc__netmgr_create(isc_mem_t *mctx, uint32_t workers, isc_nm_t **netmgrp) {
+	isc_nm_t *mgr = NULL;
+	char name[32];
+
+	REQUIRE(workers > 0);
+
+#ifdef MAXIMAL_UV_VERSION
+	if (uv_version() > MAXIMAL_UV_VERSION) {
+		isc_error_fatal(__FILE__, __LINE__,
+				"libuv version too new: running with libuv %s "
+				"when compiled with libuv %s will lead to "
+				"libuv failures",
+				uv_version_string(), UV_VERSION_STRING);
+	}
+#endif /* MAXIMAL_UV_VERSION */
+
+	if (uv_version() < MINIMAL_UV_VERSION) {
+		isc_error_fatal(__FILE__, __LINE__,
+				"libuv version too old: running with libuv %s "
+				"when compiled with libuv %s will lead to "
+				"libuv failures",
+				uv_version_string(), UV_VERSION_STRING);
+	}
+
+#ifdef WIN32
+	isc__nm_winsock_initialize();
+#endif /* WIN32 */
+
+	isc__nm_threadpool_initialize(workers);
+
+	mgr = isc_mem_get(mctx, sizeof(*mgr));
+	*mgr = (isc_nm_t){ .nworkers = workers };
+
+	isc_mem_attach(mctx, &mgr->mctx);
+	isc_mutex_init(&mgr->lock);
+	isc_condition_init(&mgr->wkstatecond);
+	isc_condition_init(&mgr->wkpausecond);
+	isc_refcount_init(&mgr->references, 1);
+	atomic_init(&mgr->maxudp, 0);
+	atomic_init(&mgr->interlocked, ISC_NETMGR_NON_INTERLOCKED);
+	atomic_init(&mgr->workers_paused, 0);
+	atomic_init(&mgr->paused, false);
+	atomic_init(&mgr->closing, false);
+#if HAVE_SO_REUSEPORT_LB
+	mgr->load_balance_sockets = true;
+#else
+	mgr->load_balance_sockets = false;
+#endif
+
+#ifdef NETMGR_TRACE
+	ISC_LIST_INIT(mgr->active_sockets);
+#endif
+
+	/*
+	 * Default TCP timeout values.
+	 * May be updated by isc_nm_tcptimeouts().
+	 */
+	atomic_init(&mgr->init, 30000);
+	atomic_init(&mgr->idle, 30000);
+	atomic_init(&mgr->keepalive, 30000);
+	atomic_init(&mgr->advertised, 30000);
+
+	isc_barrier_init(&mgr->pausing, workers);
+	isc_barrier_init(&mgr->resuming, workers);
+
+	mgr->workers = isc_mem_get(mctx, workers * sizeof(isc__networker_t));
+	for (size_t i = 0; i < workers; i++) {
+		isc__networker_t *worker = &mgr->workers[i];
+		int r;
+
+		*worker = (isc__networker_t){
+			.mgr = mgr,
+			.id = i,
+		};
+
+		r = uv_loop_init(&worker->loop);
+		UV_RUNTIME_CHECK(uv_loop_init, r);
+
+		worker->loop.data = &mgr->workers[i];
+
+		r = uv_async_init(&worker->loop, &worker->async, async_cb);
+		UV_RUNTIME_CHECK(uv_async_init, r);
+
+		for (size_t type = 0; type < NETIEVENT_MAX; type++) {
+			isc_mutex_init(&worker->ievents[type].lock);
+			isc_condition_init(&worker->ievents[type].cond);
+			ISC_LIST_INIT(worker->ievents[type].list);
+		}
+
+		worker->recvbuf = isc_mem_get(mctx, ISC_NETMGR_RECVBUF_SIZE);
+		worker->sendbuf = isc_mem_get(mctx, ISC_NETMGR_SENDBUF_SIZE);
+
+		/*
+		 * We need to do this here and not in nm_thread to avoid a
+		 * race - we could exit isc_nm_start, launch nm_destroy,
+		 * and nm_thread would still not be up.
+		 */
+		mgr->workers_running++;
+		isc_thread_create(nm_thread, &mgr->workers[i], &worker->thread);
+
+		snprintf(name, sizeof(name), "isc-net-%04zu", i);
+		isc_thread_setname(worker->thread, name);
+	}
+
+	mgr->magic = NM_MAGIC;
+	*netmgrp = mgr;
+}
+
+/*
+ * Free the resources of the network manager.
+ */
+static void
+nm_destroy(isc_nm_t **mgr0) {
+	REQUIRE(VALID_NM(*mgr0));
+	REQUIRE(!isc__nm_in_netthread());
+
+	isc_nm_t *mgr = *mgr0;
+	*mgr0 = NULL;
+
+	isc_refcount_destroy(&mgr->references);
+
+	mgr->magic = 0;
+
+	for (int i = 0; i < mgr->nworkers; i++) {
+		isc__networker_t *worker = &mgr->workers[i];
+		isc__netievent_t *event = isc__nm_get_netievent_stop(mgr);
+		isc__nm_enqueue_ievent(worker, event);
+	}
+
+	LOCK(&mgr->lock);
+	while (mgr->workers_running > 0) {
+		WAIT(&mgr->wkstatecond, &mgr->lock);
+	}
+	UNLOCK(&mgr->lock);
+
+	for (int i = 0; i < mgr->nworkers; i++) {
+		isc__networker_t *worker = &mgr->workers[i];
+		int r;
+
+		r = uv_loop_close(&worker->loop);
+		UV_RUNTIME_CHECK(uv_loop_close, r);
+
+		for (size_t type = 0; type < NETIEVENT_MAX; type++) {
+			INSIST(ISC_LIST_EMPTY(worker->ievents[type].list));
+			isc_condition_destroy(&worker->ievents[type].cond);
+			isc_mutex_destroy(&worker->ievents[type].lock);
+		}
+
+		isc_mem_put(mgr->mctx, worker->sendbuf,
+			    ISC_NETMGR_SENDBUF_SIZE);
+		isc_mem_put(mgr->mctx, worker->recvbuf,
+			    ISC_NETMGR_RECVBUF_SIZE);
+		isc_thread_join(worker->thread, NULL);
+	}
+
+	if (mgr->stats != NULL) {
+		isc_stats_detach(&mgr->stats);
+	}
+
+	isc_barrier_destroy(&mgr->resuming);
+	isc_barrier_destroy(&mgr->pausing);
+
+	isc_condition_destroy(&mgr->wkstatecond);
+	isc_condition_destroy(&mgr->wkpausecond);
+	isc_mutex_destroy(&mgr->lock);
+
+	isc_mem_put(mgr->mctx, mgr->workers,
+		    mgr->nworkers * sizeof(isc__networker_t));
+	isc_mem_putanddetach(&mgr->mctx, mgr, sizeof(*mgr));
+
+#ifdef WIN32
+	isc__nm_winsock_destroy();
+#endif /* WIN32 */
+}
+
+static void
+enqueue_pause(isc__networker_t *worker) {
+	isc__netievent_pause_t *event =
+		isc__nm_get_netievent_pause(worker->mgr);
+	isc__nm_enqueue_ievent(worker, (isc__netievent_t *)event);
+}
+
+static void
+isc__nm_async_pause(isc__networker_t *worker, isc__netievent_t *ev0) {
+	UNUSED(ev0);
+	REQUIRE(worker->paused == false);
+
+	worker->paused = true;
+	uv_stop(&worker->loop);
+}
+
+void
+isc_nm_pause(isc_nm_t *mgr) {
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(!atomic_load(&mgr->paused));
+
+	isc__nm_acquire_interlocked_force(mgr);
+
+	if (isc__nm_in_netthread()) {
+		REQUIRE(isc_nm_tid() == 0);
+	}
+
+	for (int i = 0; i < mgr->nworkers; i++) {
+		isc__networker_t *worker = &mgr->workers[i];
+		if (i == isc_nm_tid()) {
+			isc__nm_async_pause(worker, NULL);
+		} else {
+			enqueue_pause(worker);
+		}
+	}
+
+	if (isc__nm_in_netthread()) {
+		atomic_fetch_add(&mgr->workers_paused, 1);
+		isc_barrier_wait(&mgr->pausing);
+	}
+
+	LOCK(&mgr->lock);
+	while (atomic_load(&mgr->workers_paused) != mgr->workers_running) {
+		WAIT(&mgr->wkstatecond, &mgr->lock);
+	}
+	UNLOCK(&mgr->lock);
+
+	REQUIRE(atomic_compare_exchange_strong(&mgr->paused, &(bool){ false },
+					       true));
+}
+
+static void
+enqueue_resume(isc__networker_t *worker) {
+	isc__netievent_resume_t *event =
+		isc__nm_get_netievent_resume(worker->mgr);
+	isc__nm_enqueue_ievent(worker, (isc__netievent_t *)event);
+}
+
+static void
+isc__nm_async_resume(isc__networker_t *worker, isc__netievent_t *ev0) {
+	UNUSED(ev0);
+	REQUIRE(worker->paused == true);
+
+	worker->paused = false;
+}
+
+void
+isc_nm_resume(isc_nm_t *mgr) {
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(atomic_load(&mgr->paused));
+
+	if (isc__nm_in_netthread()) {
+		REQUIRE(isc_nm_tid() == 0);
+		drain_queue(&mgr->workers[isc_nm_tid()], NETIEVENT_PRIORITY);
+	}
+
+	for (int i = 0; i < mgr->nworkers; i++) {
+		isc__networker_t *worker = &mgr->workers[i];
+		if (i == isc_nm_tid()) {
+			isc__nm_async_resume(worker, NULL);
+		} else {
+			enqueue_resume(worker);
+		}
+	}
+
+	if (isc__nm_in_netthread()) {
+		drain_queue(&mgr->workers[isc_nm_tid()], NETIEVENT_PRIVILEGED);
+
+		atomic_fetch_sub(&mgr->workers_paused, 1);
+		isc_barrier_wait(&mgr->resuming);
+	}
+
+	LOCK(&mgr->lock);
+	while (atomic_load(&mgr->workers_paused) != 0) {
+		WAIT(&mgr->wkstatecond, &mgr->lock);
+	}
+	UNLOCK(&mgr->lock);
+
+	REQUIRE(atomic_compare_exchange_strong(&mgr->paused, &(bool){ true },
+					       false));
+
+	isc__nm_drop_interlocked(mgr);
+}
+
+void
+isc_nm_attach(isc_nm_t *mgr, isc_nm_t **dst) {
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(dst != NULL && *dst == NULL);
+
+	isc_refcount_increment(&mgr->references);
+
+	*dst = mgr;
+}
+
+void
+isc_nm_detach(isc_nm_t **mgr0) {
+	isc_nm_t *mgr = NULL;
+
+	REQUIRE(mgr0 != NULL);
+	REQUIRE(VALID_NM(*mgr0));
+
+	mgr = *mgr0;
+	*mgr0 = NULL;
+
+	if (isc_refcount_decrement(&mgr->references) == 1) {
+		nm_destroy(&mgr);
+	}
+}
+
+void
+isc__netmgr_shutdown(isc_nm_t *mgr) {
+	REQUIRE(VALID_NM(mgr));
+
+	atomic_store(&mgr->closing, true);
+	for (int i = 0; i < mgr->nworkers; i++) {
+		isc__netievent_t *event = NULL;
+		event = isc__nm_get_netievent_shutdown(mgr);
+		isc__nm_enqueue_ievent(&mgr->workers[i], event);
+	}
+}
+
+void
+isc__netmgr_destroy(isc_nm_t **netmgrp) {
+	isc_nm_t *mgr = NULL;
+	int counter = 0;
+
+	REQUIRE(VALID_NM(*netmgrp));
+
+	mgr = *netmgrp;
+
+	/*
+	 * Close active connections.
+	 */
+	isc__netmgr_shutdown(mgr);
+
+	/*
+	 * Wait for the manager to be dereferenced elsewhere.
+	 */
+	while (isc_refcount_current(&mgr->references) > 1 && counter++ < 1000) {
+		uv_sleep(10);
+	}
+
+#ifdef NETMGR_TRACE
+	if (isc_refcount_current(&mgr->references) > 1) {
+		isc__nm_dump_active(mgr);
+		UNREACHABLE();
+	}
+#endif
+
+	/*
+	 * Now just patiently wait
+	 */
+	while (isc_refcount_current(&mgr->references) > 1) {
+		uv_sleep(10);
+	}
+
+	/*
+	 * Detach final reference.
+	 */
+	isc_nm_detach(netmgrp);
+}
+
+void
+isc_nm_maxudp(isc_nm_t *mgr, uint32_t maxudp) {
+	REQUIRE(VALID_NM(mgr));
+
+	atomic_store(&mgr->maxudp, maxudp);
+}
+
+void
+isc_nmhandle_setwritetimeout(isc_nmhandle_t *handle, uint64_t write_timeout) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	handle->sock->write_timeout = write_timeout;
+}
+
+void
+isc_nm_settimeouts(isc_nm_t *mgr, uint32_t init, uint32_t idle,
+		   uint32_t keepalive, uint32_t advertised) {
+	REQUIRE(VALID_NM(mgr));
+
+	atomic_store(&mgr->init, init);
+	atomic_store(&mgr->idle, idle);
+	atomic_store(&mgr->keepalive, keepalive);
+	atomic_store(&mgr->advertised, advertised);
+}
+
+bool
+isc_nm_getloadbalancesockets(isc_nm_t *mgr) {
+	REQUIRE(VALID_NM(mgr));
+
+	return (mgr->load_balance_sockets);
+}
+
+void
+isc_nm_setloadbalancesockets(isc_nm_t *mgr, bool enabled) {
+	REQUIRE(VALID_NM(mgr));
+
+#if HAVE_SO_REUSEPORT_LB
+	mgr->load_balance_sockets = enabled;
+#else
+	UNUSED(enabled);
+#endif
+}
+
+void
+isc_nm_gettimeouts(isc_nm_t *mgr, uint32_t *initial, uint32_t *idle,
+		   uint32_t *keepalive, uint32_t *advertised) {
+	REQUIRE(VALID_NM(mgr));
+
+	if (initial != NULL) {
+		*initial = atomic_load(&mgr->init);
+	}
+
+	if (idle != NULL) {
+		*idle = atomic_load(&mgr->idle);
+	}
+
+	if (keepalive != NULL) {
+		*keepalive = atomic_load(&mgr->keepalive);
+	}
+
+	if (advertised != NULL) {
+		*advertised = atomic_load(&mgr->advertised);
+	}
+}
+
+/*
+ * nm_thread is a single worker thread, that runs uv_run event loop
+ * until asked to stop.
+ *
+ * There are four queues for asynchronous events:
+ *
+ * 1. priority queue - netievents on the priority queue are run even when
+ *    the taskmgr enters exclusive mode and the netmgr is paused.  This
+ *    is needed to properly start listening on the interfaces, free
+ *    resources on shutdown, or resume from a pause.
+ *
+ * 2. privileged task queue - only privileged tasks are queued here and
+ *    this is the first queue that gets processed when network manager
+ *    is unpaused using isc_nm_resume().  All netmgr workers need to
+ *    clean the privileged task queue before they all proceed to normal
+ *    operation.  Both task queues are processed when the workers are
+ *    shutting down.
+ *
+ * 3. task queue - only (traditional) tasks are scheduled here, and this
+ *    queue and the privileged task queue are both processed when the
+ *    netmgr workers are finishing.  This is needed to process the task
+ *    shutdown events.
+ *
+ * 4. normal queue - this is the queue with netmgr events, e.g. reading,
+ *    sending, callbacks, etc.
+ */
+
+static isc_threadresult_t
+nm_thread(isc_threadarg_t worker0) {
+	isc__networker_t *worker = (isc__networker_t *)worker0;
+	isc_nm_t *mgr = worker->mgr;
+
+	isc__nm_tid_v = worker->id;
+
+	while (true) {
+		/*
+		 * uv_run() runs async_cb() in a loop, which processes
+		 * all four event queues until a "pause" or "stop" event
+		 * is encountered. On pause, we process only priority and
+		 * privileged events until resuming.
+		 */
+		int r = uv_run(&worker->loop, UV_RUN_DEFAULT);
+		INSIST(r > 0 || worker->finished);
+
+		if (worker->paused) {
+			INSIST(atomic_load(&mgr->interlocked) != isc_nm_tid());
+
+			atomic_fetch_add(&mgr->workers_paused, 1);
+			if (isc_barrier_wait(&mgr->pausing) != 0) {
+				LOCK(&mgr->lock);
+				SIGNAL(&mgr->wkstatecond);
+				UNLOCK(&mgr->lock);
+			}
+
+			while (worker->paused) {
+				wait_for_priority_queue(worker);
+			}
+
+			/*
+			 * All workers must drain the privileged event
+			 * queue before we resume from pause.
+			 */
+			drain_queue(worker, NETIEVENT_PRIVILEGED);
+
+			atomic_fetch_sub(&mgr->workers_paused, 1);
+			if (isc_barrier_wait(&mgr->resuming) != 0) {
+				LOCK(&mgr->lock);
+				SIGNAL(&mgr->wkstatecond);
+				UNLOCK(&mgr->lock);
+			}
+		}
+
+		if (r == 0) {
+			INSIST(worker->finished);
+			break;
+		}
+
+		INSIST(!worker->finished);
+	}
+
+	/*
+	 * We are shutting down.  Drain the queues.
+	 */
+	drain_queue(worker, NETIEVENT_PRIVILEGED);
+	drain_queue(worker, NETIEVENT_TASK);
+
+	for (size_t type = 0; type < NETIEVENT_MAX; type++) {
+		LOCK(&worker->ievents[type].lock);
+		INSIST(ISC_LIST_EMPTY(worker->ievents[type].list));
+		UNLOCK(&worker->ievents[type].lock);
+	}
+
+	LOCK(&mgr->lock);
+	mgr->workers_running--;
+	SIGNAL(&mgr->wkstatecond);
+	UNLOCK(&mgr->lock);
+
+	return ((isc_threadresult_t)0);
+}
+
+static bool
+process_all_queues(isc__networker_t *worker) {
+	bool reschedule = false;
+	/*
+	 * The queue processing functions will return false when the
+	 * system is pausing or stopping and we don't want to process
+	 * the other queues in such case, but we need the async event
+	 * to be rescheduled in the next uv_run().
+	 */
+	for (size_t type = 0; type < NETIEVENT_MAX; type++) {
+		isc_result_t result = process_queue(worker, type);
+		switch (result) {
+		case ISC_R_SUSPEND:
+			reschedule = true;
+			break;
+		case ISC_R_EMPTY:
+			/* empty queue */
+			break;
+		case ISC_R_SUCCESS:
+			reschedule = true;
+			break;
+		default:
+			UNREACHABLE();
+		}
+	}
+
+	return (reschedule);
+}
+
+/*
+ * async_cb() is a universal callback for 'async' events sent to event loop.
+ * It's the only way to safely pass data to the libuv event loop. We use a
+ * single async event and a set of lockless queues of 'isc__netievent_t'
+ * structures passed from other threads.
+ */
+static void
+async_cb(uv_async_t *handle) {
+	isc__networker_t *worker = (isc__networker_t *)handle->loop->data;
+
+	if (process_all_queues(worker)) {
+		/*
+		 * If we didn't process all the events, we need to enqueue
+		 * async_cb to be run in the next iteration of the uv_loop
+		 */
+		uv_async_send(handle);
+	}
+}
+
+static void
+isc__nm_async_stop(isc__networker_t *worker, isc__netievent_t *ev0) {
+	UNUSED(ev0);
+	worker->finished = true;
+	/* Close the async handler */
+	uv_close((uv_handle_t *)&worker->async, NULL);
+}
+
+void
+isc_nm_task_enqueue(isc_nm_t *nm, isc_task_t *task, int threadid) {
+	isc__netievent_t *event = NULL;
+	int tid;
+	isc__networker_t *worker = NULL;
+
+	if (threadid == -1) {
+		tid = (int)isc_random_uniform(nm->nworkers);
+	} else {
+		tid = threadid % nm->nworkers;
+	}
+
+	worker = &nm->workers[tid];
+
+	if (isc_task_privileged(task)) {
+		event = (isc__netievent_t *)
+			isc__nm_get_netievent_privilegedtask(nm, task);
+	} else {
+		event = (isc__netievent_t *)isc__nm_get_netievent_task(nm,
+								       task);
+	}
+
+	isc__nm_enqueue_ievent(worker, event);
+}
+
+#define isc__nm_async_privilegedtask(worker, ev0) \
+	isc__nm_async_task(worker, ev0)
+
+static void
+isc__nm_async_task(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_task_t *ievent = (isc__netievent_task_t *)ev0;
+	isc_result_t result;
+
+	UNUSED(worker);
+
+	result = isc_task_run(ievent->task);
+
+	switch (result) {
+	case ISC_R_QUOTA:
+		isc_task_ready(ievent->task);
+		return;
+	case ISC_R_SUCCESS:
+		return;
+	default:
+		UNREACHABLE();
+	}
+}
+
+static void
+wait_for_priority_queue(isc__networker_t *worker) {
+	isc_condition_t *cond = &worker->ievents[NETIEVENT_PRIORITY].cond;
+	isc_mutex_t *lock = &worker->ievents[NETIEVENT_PRIORITY].lock;
+	isc__netievent_list_t *list =
+		&(worker->ievents[NETIEVENT_PRIORITY].list);
+
+	LOCK(lock);
+	while (ISC_LIST_EMPTY(*list)) {
+		WAIT(cond, lock);
+	}
+	UNLOCK(lock);
+
+	drain_queue(worker, NETIEVENT_PRIORITY);
+}
+
+static void
+drain_queue(isc__networker_t *worker, netievent_type_t type) {
+	bool empty = false;
+	while (!empty) {
+		if (process_queue(worker, type) == ISC_R_EMPTY) {
+			LOCK(&worker->ievents[type].lock);
+			empty = ISC_LIST_EMPTY(worker->ievents[type].list);
+			UNLOCK(&worker->ievents[type].lock);
+		}
+	}
+}
+
+/*
+ * The two macros here generate the individual cases for the process_netievent()
+ * function.  The NETIEVENT_CASE(type) macro is the common case, and
+ * NETIEVENT_CASE_NOMORE(type) is a macro that causes the loop in the
+ * process_queue() to stop, e.g. it's only used for the netievent that
+ * stops/pauses processing the enqueued netievents.
+ */
+#define NETIEVENT_CASE(type)                                               \
+	case netievent_##type: {                                           \
+		isc__nm_async_##type(worker, ievent);                      \
+		isc__nm_put_netievent_##type(                              \
+			worker->mgr, (isc__netievent_##type##_t *)ievent); \
+		return (true);                                             \
+	}
+
+#define NETIEVENT_CASE_NOMORE(type)                                \
+	case netievent_##type: {                                   \
+		isc__nm_async_##type(worker, ievent);              \
+		isc__nm_put_netievent_##type(worker->mgr, ievent); \
+		return (false);                                    \
+	}
+
+static bool
+process_netievent(isc__networker_t *worker, isc__netievent_t *ievent) {
+	REQUIRE(worker->id == isc_nm_tid());
+
+	switch (ievent->type) {
+		/* Don't process more ievents when we are stopping */
+		NETIEVENT_CASE_NOMORE(stop);
+
+		NETIEVENT_CASE(privilegedtask);
+		NETIEVENT_CASE(task);
+
+		NETIEVENT_CASE(udpconnect);
+		NETIEVENT_CASE(udplisten);
+		NETIEVENT_CASE(udpstop);
+		NETIEVENT_CASE(udpsend);
+		NETIEVENT_CASE(udpread);
+		NETIEVENT_CASE(udpcancel);
+		NETIEVENT_CASE(udpclose);
+
+		NETIEVENT_CASE(tcpaccept);
+		NETIEVENT_CASE(tcpconnect);
+		NETIEVENT_CASE(tcplisten);
+		NETIEVENT_CASE(tcpstartread);
+		NETIEVENT_CASE(tcppauseread);
+		NETIEVENT_CASE(tcpsend);
+		NETIEVENT_CASE(tcpstop);
+		NETIEVENT_CASE(tcpcancel);
+		NETIEVENT_CASE(tcpclose);
+
+		NETIEVENT_CASE(tcpdnsaccept);
+		NETIEVENT_CASE(tcpdnslisten);
+		NETIEVENT_CASE(tcpdnsconnect);
+		NETIEVENT_CASE(tcpdnssend);
+		NETIEVENT_CASE(tcpdnscancel);
+		NETIEVENT_CASE(tcpdnsclose);
+		NETIEVENT_CASE(tcpdnsread);
+		NETIEVENT_CASE(tcpdnsstop);
+
+		NETIEVENT_CASE(connectcb);
+		NETIEVENT_CASE(readcb);
+		NETIEVENT_CASE(sendcb);
+
+		NETIEVENT_CASE(close);
+		NETIEVENT_CASE(detach);
+
+		NETIEVENT_CASE(shutdown);
+		NETIEVENT_CASE(resume);
+		NETIEVENT_CASE_NOMORE(pause);
+	default:
+		UNREACHABLE();
+	}
+	return (true);
+}
+
+static isc_result_t
+process_queue(isc__networker_t *worker, netievent_type_t type) {
+	isc__netievent_t *ievent = NULL;
+	isc__netievent_list_t list;
+
+	ISC_LIST_INIT(list);
+
+	LOCK(&worker->ievents[type].lock);
+	ISC_LIST_MOVE(list, worker->ievents[type].list);
+	UNLOCK(&worker->ievents[type].lock);
+
+	ievent = ISC_LIST_HEAD(list);
+	if (ievent == NULL) {
+		/* There's nothing scheduled */
+		return (ISC_R_EMPTY);
+	}
+
+	while (ievent != NULL) {
+		isc__netievent_t *next = ISC_LIST_NEXT(ievent, link);
+		ISC_LIST_DEQUEUE(list, ievent, link);
+
+		if (!process_netievent(worker, ievent)) {
+			/* The netievent told us to stop */
+			if (!ISC_LIST_EMPTY(list)) {
+				/*
+				 * Reschedule the rest of the unprocessed
+				 * events.
+				 */
+				LOCK(&worker->ievents[type].lock);
+				ISC_LIST_PREPENDLIST(worker->ievents[type].list,
+						     list, link);
+				UNLOCK(&worker->ievents[type].lock);
+			}
+			return (ISC_R_SUSPEND);
+		}
+
+		ievent = next;
+	}
+
+	/* We processed at least one */
+	return (ISC_R_SUCCESS);
+}
+
+void *
+isc__nm_get_netievent(isc_nm_t *mgr, isc__netievent_type type) {
+	isc__netievent_storage_t *event = isc_mem_get(mgr->mctx,
+						      sizeof(*event));
+
+	*event = (isc__netievent_storage_t){ .ni.type = type };
+	ISC_LINK_INIT(&(event->ni), link);
+	return (event);
+}
+
+void
+isc__nm_put_netievent(isc_nm_t *mgr, void *ievent) {
+	isc_mem_put(mgr->mctx, ievent, sizeof(isc__netievent_storage_t));
+}
+
+NETIEVENT_SOCKET_DEF(tcpclose);
+NETIEVENT_SOCKET_DEF(tcplisten);
+NETIEVENT_SOCKET_DEF(tcppauseread);
+NETIEVENT_SOCKET_DEF(tcpstartread);
+NETIEVENT_SOCKET_DEF(tcpstop);
+NETIEVENT_SOCKET_DEF(udpclose);
+NETIEVENT_SOCKET_DEF(udplisten);
+NETIEVENT_SOCKET_DEF(udpread);
+NETIEVENT_SOCKET_DEF(udpsend);
+NETIEVENT_SOCKET_DEF(udpstop);
+
+NETIEVENT_SOCKET_DEF(tcpdnsclose);
+NETIEVENT_SOCKET_DEF(tcpdnsread);
+NETIEVENT_SOCKET_DEF(tcpdnsstop);
+NETIEVENT_SOCKET_DEF(tcpdnslisten);
+NETIEVENT_SOCKET_REQ_DEF(tcpdnsconnect);
+NETIEVENT_SOCKET_REQ_DEF(tcpdnssend);
+NETIEVENT_SOCKET_HANDLE_DEF(tcpdnscancel);
+NETIEVENT_SOCKET_QUOTA_DEF(tcpdnsaccept);
+
+NETIEVENT_SOCKET_REQ_DEF(tcpconnect);
+NETIEVENT_SOCKET_REQ_DEF(tcpsend);
+NETIEVENT_SOCKET_REQ_DEF(udpconnect);
+NETIEVENT_SOCKET_REQ_RESULT_DEF(connectcb);
+NETIEVENT_SOCKET_REQ_RESULT_DEF(readcb);
+NETIEVENT_SOCKET_REQ_RESULT_DEF(sendcb);
+
+NETIEVENT_SOCKET_DEF(detach);
+NETIEVENT_SOCKET_HANDLE_DEF(tcpcancel);
+NETIEVENT_SOCKET_HANDLE_DEF(udpcancel);
+
+NETIEVENT_SOCKET_QUOTA_DEF(tcpaccept);
+
+NETIEVENT_SOCKET_DEF(close);
+NETIEVENT_DEF(pause);
+NETIEVENT_DEF(resume);
+NETIEVENT_DEF(shutdown);
+NETIEVENT_DEF(stop);
+
+NETIEVENT_TASK_DEF(task);
+NETIEVENT_TASK_DEF(privilegedtask);
+
+void
+isc__nm_maybe_enqueue_ievent(isc__networker_t *worker,
+			     isc__netievent_t *event) {
+	/*
+	 * If we are already in the matching nmthread, process the ievent
+	 * directly.
+	 */
+	if (worker->id == isc_nm_tid()) {
+		process_netievent(worker, event);
+		return;
+	}
+
+	isc__nm_enqueue_ievent(worker, event);
+}
+
+void
+isc__nm_enqueue_ievent(isc__networker_t *worker, isc__netievent_t *event) {
+	netievent_type_t type;
+
+	if (event->type > netievent_prio) {
+		type = NETIEVENT_PRIORITY;
+	} else {
+		switch (event->type) {
+		case netievent_prio:
+			UNREACHABLE();
+			break;
+		case netievent_privilegedtask:
+			type = NETIEVENT_PRIVILEGED;
+			break;
+		case netievent_task:
+			type = NETIEVENT_TASK;
+			break;
+		default:
+			type = NETIEVENT_NORMAL;
+			break;
+		}
+	}
+
+	/*
+	 * We need to make sure this signal will be delivered and
+	 * the queue will be processed.
+	 */
+	LOCK(&worker->ievents[type].lock);
+	ISC_LIST_ENQUEUE(worker->ievents[type].list, event, link);
+	if (type == NETIEVENT_PRIORITY) {
+		SIGNAL(&worker->ievents[type].cond);
+	}
+	UNLOCK(&worker->ievents[type].lock);
+
+	uv_async_send(&worker->async);
+}
+
+bool
+isc__nmsocket_active(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	if (sock->parent != NULL) {
+		return (atomic_load(&sock->parent->active));
+	}
+
+	return (atomic_load(&sock->active));
+}
+
+bool
+isc__nmsocket_deactivate(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+
+	if (sock->parent != NULL) {
+		return (atomic_compare_exchange_strong(&sock->parent->active,
+						       &(bool){ true }, false));
+	}
+
+	return (atomic_compare_exchange_strong(&sock->active, &(bool){ true },
+					       false));
+}
+
+void
+isc___nmsocket_attach(isc_nmsocket_t *sock, isc_nmsocket_t **target FLARG) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(target != NULL && *target == NULL);
+
+	isc_nmsocket_t *rsock = NULL;
+
+	if (sock->parent != NULL) {
+		rsock = sock->parent;
+		INSIST(rsock->parent == NULL); /* sanity check */
+	} else {
+		rsock = sock;
+	}
+
+	NETMGR_TRACE_LOG("isc__nmsocket_attach():%p->references = %" PRIuFAST32
+			 "\n",
+			 rsock, isc_refcount_current(&rsock->references) + 1);
+
+	isc_refcount_increment0(&rsock->references);
+
+	*target = sock;
+}
+
+/*
+ * Free all resources inside a socket (including its children if any).
+ */
+static void
+nmsocket_cleanup(isc_nmsocket_t *sock, bool dofree FLARG) {
+	isc_nmhandle_t *handle = NULL;
+	isc__nm_uvreq_t *uvreq = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(!isc__nmsocket_active(sock));
+
+	NETMGR_TRACE_LOG("nmsocket_cleanup():%p->references = %" PRIuFAST32
+			 "\n",
+			 sock, isc_refcount_current(&sock->references));
+
+	atomic_store(&sock->destroying, true);
+
+	if (sock->parent == NULL && sock->children != NULL) {
+		/*
+		 * We shouldn't be here unless there are no active handles,
+		 * so we can clean up and free the children.
+		 */
+		for (size_t i = 0; i < sock->nchildren; i++) {
+			if (!atomic_load(&sock->children[i].destroying)) {
+				nmsocket_cleanup(&sock->children[i],
+						 false FLARG_PASS);
+			}
+		}
+
+		/*
+		 * This was a parent socket: destroy the listening
+		 * barriers that synchronized the children.
+		 */
+		isc_barrier_destroy(&sock->startlistening);
+		isc_barrier_destroy(&sock->stoplistening);
+
+		/*
+		 * Now free them.
+		 */
+		isc_mem_put(sock->mgr->mctx, sock->children,
+			    sock->nchildren * sizeof(*sock));
+		sock->children = NULL;
+		sock->nchildren = 0;
+	}
+	if (sock->statsindex != NULL) {
+		isc__nm_decstats(sock->mgr, sock->statsindex[STATID_ACTIVE]);
+	}
+
+	sock->statichandle = NULL;
+
+	if (sock->outerhandle != NULL) {
+		isc__nmhandle_detach(&sock->outerhandle FLARG_PASS);
+	}
+
+	if (sock->outer != NULL) {
+		isc___nmsocket_detach(&sock->outer FLARG_PASS);
+	}
+
+	while ((handle = isc_astack_pop(sock->inactivehandles)) != NULL) {
+		nmhandle_free(sock, handle);
+	}
+
+	if (sock->buf != NULL) {
+		isc_mem_free(sock->mgr->mctx, sock->buf);
+	}
+
+	if (sock->quota != NULL) {
+		isc_quota_detach(&sock->quota);
+	}
+
+	sock->pquota = NULL;
+
+	isc_astack_destroy(sock->inactivehandles);
+
+	while ((uvreq = isc_astack_pop(sock->inactivereqs)) != NULL) {
+		isc_mem_put(sock->mgr->mctx, uvreq, sizeof(*uvreq));
+	}
+
+	isc_astack_destroy(sock->inactivereqs);
+	sock->magic = 0;
+
+	isc_condition_destroy(&sock->scond);
+	isc_condition_destroy(&sock->cond);
+	isc_mutex_destroy(&sock->lock);
+#ifdef NETMGR_TRACE
+	LOCK(&sock->mgr->lock);
+	ISC_LIST_UNLINK(sock->mgr->active_sockets, sock, active_link);
+	UNLOCK(&sock->mgr->lock);
+#endif
+	if (dofree) {
+		isc_nm_t *mgr = sock->mgr;
+		isc_mem_put(mgr->mctx, sock, sizeof(*sock));
+		isc_nm_detach(&mgr);
+	} else {
+		isc_nm_detach(&sock->mgr);
+	}
+}
+
+static void
+nmsocket_maybe_destroy(isc_nmsocket_t *sock FLARG) {
+	int active_handles;
+	bool destroy = false;
+
+	NETMGR_TRACE_LOG("%s():%p->references = %" PRIuFAST32 "\n", __func__,
+			 sock, isc_refcount_current(&sock->references));
+
+	if (sock->parent != NULL) {
+		/*
+		 * This is a child socket and cannot be destroyed except
+		 * as a side effect of destroying the parent, so let's go
+		 * see if the parent is ready to be destroyed.
+		 */
+		nmsocket_maybe_destroy(sock->parent FLARG_PASS);
+		return;
+	}
+
+	/*
+	 * This is a parent socket (or a standalone). See whether the
+	 * children have active handles before deciding whether to
+	 * accept destruction.
+	 */
+	LOCK(&sock->lock);
+	if (atomic_load(&sock->active) || atomic_load(&sock->destroying) ||
+	    !atomic_load(&sock->closed) || atomic_load(&sock->references) != 0)
+	{
+		UNLOCK(&sock->lock);
+		return;
+	}
+
+	active_handles = atomic_load(&sock->ah);
+	if (sock->children != NULL) {
+		for (size_t i = 0; i < sock->nchildren; i++) {
+			LOCK(&sock->children[i].lock);
+			active_handles += atomic_load(&sock->children[i].ah);
+			UNLOCK(&sock->children[i].lock);
+		}
+	}
+
+	if (active_handles == 0 || sock->statichandle != NULL) {
+		destroy = true;
+	}
+
+	NETMGR_TRACE_LOG("%s:%p->active_handles = %d, .statichandle = %p\n",
+			 __func__, sock, active_handles, sock->statichandle);
+
+	if (destroy) {
+		atomic_store(&sock->destroying, true);
+		UNLOCK(&sock->lock);
+		nmsocket_cleanup(sock, true FLARG_PASS);
+	} else {
+		UNLOCK(&sock->lock);
+	}
+}
+
+void
+isc___nmsocket_prep_destroy(isc_nmsocket_t *sock FLARG) {
+	REQUIRE(sock->parent == NULL);
+
+	NETMGR_TRACE_LOG("isc___nmsocket_prep_destroy():%p->references = "
+			 "%" PRIuFAST32 "\n",
+			 sock, isc_refcount_current(&sock->references));
+
+	/*
+	 * The final external reference to the socket is gone. We can try
+	 * destroying the socket, but we have to wait for all the inflight
+	 * handles to finish first.
+	 */
+	atomic_store(&sock->active, false);
+
+	/*
+	 * If the socket has children, they'll need to be marked inactive
+	 * so they can be cleaned up too.
+	 */
+	if (sock->children != NULL) {
+		for (size_t i = 0; i < sock->nchildren; i++) {
+			atomic_store(&sock->children[i].active, false);
+		}
+	}
+
+	/*
+	 * If we're here then we already stopped listening; otherwise
+	 * we'd have a hanging reference from the listening process.
+	 *
+	 * If it's a regular socket we may need to close it.
+	 */
+	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;
+		case isc_nm_tcpdnssocket:
+			isc__nm_tcpdns_close(sock);
+			return;
+		default:
+			break;
+		}
+	}
+
+	nmsocket_maybe_destroy(sock FLARG_PASS);
+}
+
+void
+isc___nmsocket_detach(isc_nmsocket_t **sockp FLARG) {
+	REQUIRE(sockp != NULL && *sockp != NULL);
+	REQUIRE(VALID_NMSOCK(*sockp));
+
+	isc_nmsocket_t *sock = *sockp, *rsock = NULL;
+	*sockp = NULL;
+
+	/*
+	 * If the socket is a part of a set (a child socket) we are
+	 * counting references for the whole set at the parent.
+	 */
+	if (sock->parent != NULL) {
+		rsock = sock->parent;
+		INSIST(rsock->parent == NULL); /* Sanity check */
+	} else {
+		rsock = sock;
+	}
+
+	NETMGR_TRACE_LOG("isc__nmsocket_detach():%p->references = %" PRIuFAST32
+			 "\n",
+			 rsock, isc_refcount_current(&rsock->references) - 1);
+
+	if (isc_refcount_decrement(&rsock->references) == 1) {
+		isc___nmsocket_prep_destroy(rsock FLARG_PASS);
+	}
+}
+
+void
+isc_nmsocket_close(isc_nmsocket_t **sockp) {
+	REQUIRE(sockp != NULL);
+	REQUIRE(VALID_NMSOCK(*sockp));
+	REQUIRE((*sockp)->type == isc_nm_udplistener ||
+		(*sockp)->type == isc_nm_tcplistener ||
+		(*sockp)->type == isc_nm_tcpdnslistener);
+
+	isc__nmsocket_detach(sockp);
+}
+
+void
+isc___nmsocket_init(isc_nmsocket_t *sock, isc_nm_t *mgr, isc_nmsocket_type type,
+		    isc_sockaddr_t *iface FLARG) {
+	uint16_t family;
+
+	REQUIRE(sock != NULL);
+	REQUIRE(mgr != NULL);
+	REQUIRE(iface != NULL);
+
+	family = iface->type.sa.sa_family;
+
+	*sock = (isc_nmsocket_t){ .type = type,
+				  .iface = *iface,
+				  .fd = -1,
+				  .inactivehandles = isc_astack_new(
+					  mgr->mctx, ISC_NM_HANDLES_STACK_SIZE),
+				  .inactivereqs = isc_astack_new(
+					  mgr->mctx, ISC_NM_REQS_STACK_SIZE) };
+
+#if NETMGR_TRACE
+	sock->backtrace_size = backtrace(sock->backtrace, TRACE_SIZE);
+	ISC_LINK_INIT(sock, active_link);
+	ISC_LIST_INIT(sock->active_handles);
+	LOCK(&mgr->lock);
+	ISC_LIST_APPEND(mgr->active_sockets, sock, active_link);
+	UNLOCK(&mgr->lock);
+#endif
+
+	isc_nm_attach(mgr, &sock->mgr);
+	sock->uv_handle.handle.data = sock;
+
+	ISC_LINK_INIT(&sock->quotacb, link);
+
+	switch (type) {
+	case isc_nm_udpsocket:
+	case isc_nm_udplistener:
+		if (family == AF_INET) {
+			sock->statsindex = udp4statsindex;
+		} else {
+			sock->statsindex = udp6statsindex;
+		}
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_ACTIVE]);
+		break;
+	case isc_nm_tcpsocket:
+	case isc_nm_tcplistener:
+	case isc_nm_tcpdnssocket:
+	case isc_nm_tcpdnslistener:
+		if (family == AF_INET) {
+			sock->statsindex = tcp4statsindex;
+		} else {
+			sock->statsindex = tcp6statsindex;
+		}
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_ACTIVE]);
+		break;
+	default:
+		break;
+	}
+
+	isc_mutex_init(&sock->lock);
+	isc_condition_init(&sock->cond);
+	isc_condition_init(&sock->scond);
+	isc_refcount_init(&sock->references, 1);
+
+	NETMGR_TRACE_LOG("isc__nmsocket_init():%p->references = %" PRIuFAST32
+			 "\n",
+			 sock, isc_refcount_current(&sock->references));
+
+	atomic_init(&sock->active, true);
+	atomic_init(&sock->sequential, false);
+	atomic_init(&sock->readpaused, false);
+	atomic_init(&sock->closing, false);
+	atomic_init(&sock->listening, 0);
+	atomic_init(&sock->closed, 0);
+	atomic_init(&sock->destroying, 0);
+	atomic_init(&sock->ah, 0);
+	atomic_init(&sock->client, 0);
+	atomic_init(&sock->connecting, false);
+	atomic_init(&sock->keepalive, false);
+	atomic_init(&sock->connected, false);
+	atomic_init(&sock->timedout, false);
+
+	atomic_init(&sock->active_child_connections, 0);
+
+	sock->magic = NMSOCK_MAGIC;
+}
+
+void
+isc__nmsocket_clearcb(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(!isc__nm_in_netthread() || sock->tid == isc_nm_tid());
+
+	sock->recv_cb = NULL;
+	sock->recv_cbarg = NULL;
+	sock->accept_cb = NULL;
+	sock->accept_cbarg = NULL;
+	sock->connect_cb = NULL;
+	sock->connect_cbarg = NULL;
+}
+
+void
+isc__nm_free_uvbuf(isc_nmsocket_t *sock, const uv_buf_t *buf) {
+	isc__networker_t *worker = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+
+	worker = &sock->mgr->workers[sock->tid];
+	REQUIRE(buf->base == worker->recvbuf);
+
+	worker->recvbuf_inuse = false;
+}
+
+static isc_nmhandle_t *
+alloc_handle(isc_nmsocket_t *sock) {
+	isc_nmhandle_t *handle =
+		isc_mem_get(sock->mgr->mctx,
+			    sizeof(isc_nmhandle_t) + sock->extrahandlesize);
+
+	*handle = (isc_nmhandle_t){ .magic = NMHANDLE_MAGIC };
+#ifdef NETMGR_TRACE
+	ISC_LINK_INIT(handle, active_link);
+#endif
+	isc_refcount_init(&handle->references, 1);
+
+	return (handle);
+}
+
+isc_nmhandle_t *
+isc___nmhandle_get(isc_nmsocket_t *sock, isc_sockaddr_t *peer,
+		   isc_sockaddr_t *local FLARG) {
+	isc_nmhandle_t *handle = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+
+	handle = isc_astack_pop(sock->inactivehandles);
+
+	if (handle == NULL) {
+		handle = alloc_handle(sock);
+	} else {
+		isc_refcount_init(&handle->references, 1);
+		INSIST(VALID_NMHANDLE(handle));
+	}
+
+	NETMGR_TRACE_LOG(
+		"isc__nmhandle_get():handle %p->references = %" PRIuFAST32 "\n",
+		handle, isc_refcount_current(&handle->references));
+
+	isc___nmsocket_attach(sock, &handle->sock FLARG_PASS);
+
+#if NETMGR_TRACE
+	handle->backtrace_size = backtrace(handle->backtrace, TRACE_SIZE);
+#endif
+
+	if (peer != NULL) {
+		handle->peer = *peer;
+	} else {
+		handle->peer = sock->peer;
+	}
+
+	if (local != NULL) {
+		handle->local = *local;
+	} else {
+		handle->local = sock->iface;
+	}
+
+	(void)atomic_fetch_add(&sock->ah, 1);
+
+#ifdef NETMGR_TRACE
+	LOCK(&sock->lock);
+	ISC_LIST_APPEND(sock->active_handles, handle, active_link);
+	UNLOCK(&sock->lock);
+#endif
+
+	switch (sock->type) {
+	case isc_nm_udpsocket:
+	case isc_nm_tcpdnssocket:
+		if (!atomic_load(&sock->client)) {
+			break;
+		}
+		FALLTHROUGH;
+	case isc_nm_tcpsocket:
+		INSIST(sock->statichandle == NULL);
+
+		/*
+		 * statichandle must be assigned, not attached;
+		 * otherwise, if a handle was detached elsewhere
+		 * it could never reach 0 references, and the
+		 * handle and socket would never be freed.
+		 */
+		sock->statichandle = handle;
+		break;
+	default:
+		break;
+	}
+
+	return (handle);
+}
+
+void
+isc__nmhandle_attach(isc_nmhandle_t *handle, isc_nmhandle_t **handlep FLARG) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(handlep != NULL && *handlep == NULL);
+
+	NETMGR_TRACE_LOG("isc__nmhandle_attach():handle %p->references = "
+			 "%" PRIuFAST32 "\n",
+			 handle, isc_refcount_current(&handle->references) + 1);
+
+	isc_refcount_increment(&handle->references);
+	*handlep = handle;
+}
+
+bool
+isc_nmhandle_is_stream(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	return (handle->sock->type == isc_nm_tcpsocket ||
+		handle->sock->type == isc_nm_tcpdnssocket);
+}
+
+static void
+nmhandle_free(isc_nmsocket_t *sock, isc_nmhandle_t *handle) {
+	size_t extra = sock->extrahandlesize;
+
+	isc_refcount_destroy(&handle->references);
+
+	if (handle->dofree != NULL) {
+		handle->dofree(handle->opaque);
+	}
+
+	*handle = (isc_nmhandle_t){ .magic = 0 };
+
+	isc_mem_put(sock->mgr->mctx, handle, sizeof(isc_nmhandle_t) + extra);
+}
+
+static void
+nmhandle_deactivate(isc_nmsocket_t *sock, isc_nmhandle_t *handle) {
+	bool reuse = false;
+
+	/*
+	 * We do all of this under lock to avoid races with socket
+	 * destruction.  We have to do this now, because at this point the
+	 * socket is either unused or still attached to event->sock.
+	 */
+	LOCK(&sock->lock);
+
+#ifdef NETMGR_TRACE
+	ISC_LIST_UNLINK(sock->active_handles, handle, active_link);
+#endif
+
+	INSIST(atomic_fetch_sub(&sock->ah, 1) > 0);
+
+#if !__SANITIZE_ADDRESS__ && !__SANITIZE_THREAD__
+	if (atomic_load(&sock->active)) {
+		reuse = isc_astack_trypush(sock->inactivehandles, handle);
+	}
+#endif /* !__SANITIZE_ADDRESS__ && !__SANITIZE_THREAD__ */
+	if (!reuse) {
+		nmhandle_free(sock, handle);
+	}
+	UNLOCK(&sock->lock);
+}
+
+void
+isc__nmhandle_detach(isc_nmhandle_t **handlep FLARG) {
+	isc_nmsocket_t *sock = NULL;
+	isc_nmhandle_t *handle = NULL;
+
+	REQUIRE(handlep != NULL);
+	REQUIRE(VALID_NMHANDLE(*handlep));
+
+	handle = *handlep;
+	*handlep = NULL;
+
+	/*
+	 * If the closehandle_cb is set, it needs to run asynchronously to
+	 * ensure correct ordering of the isc__nm_process_sock_buffer().
+	 */
+	sock = handle->sock;
+	if (sock->tid == isc_nm_tid() && sock->closehandle_cb == NULL) {
+		nmhandle_detach_cb(&handle FLARG_PASS);
+	} else {
+		isc__netievent_detach_t *event =
+			isc__nm_get_netievent_detach(sock->mgr, sock);
+		/*
+		 * we are using implicit "attach" as the last reference
+		 * need to be destroyed explicitly in the async callback
+		 */
+		event->handle = handle;
+		FLARG_IEVENT_PASS(event);
+		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)event);
+	}
+}
+
+void
+isc__nmsocket_shutdown(isc_nmsocket_t *sock);
+
+static void
+nmhandle_detach_cb(isc_nmhandle_t **handlep FLARG) {
+	isc_nmsocket_t *sock = NULL;
+	isc_nmhandle_t *handle = NULL;
+
+	REQUIRE(handlep != NULL);
+	REQUIRE(VALID_NMHANDLE(*handlep));
+
+	handle = *handlep;
+	*handlep = NULL;
+
+	NETMGR_TRACE_LOG("isc__nmhandle_detach():%p->references = %" PRIuFAST32
+			 "\n",
+			 handle, isc_refcount_current(&handle->references) - 1);
+
+	if (isc_refcount_decrement(&handle->references) > 1) {
+		return;
+	}
+
+	/* We need an acquire memory barrier here */
+	(void)isc_refcount_current(&handle->references);
+
+	sock = handle->sock;
+	handle->sock = NULL;
+
+	if (handle->doreset != NULL) {
+		handle->doreset(handle->opaque);
+	}
+
+	nmhandle_deactivate(sock, handle);
+
+	/*
+	 * The handle is gone now. If the socket has a callback configured
+	 * for that (e.g., to perform cleanup after request processing),
+	 * call it now, or schedule it to run asynchronously.
+	 */
+	if (sock->closehandle_cb != NULL) {
+		if (sock->tid == isc_nm_tid()) {
+			sock->closehandle_cb(sock);
+		} else {
+			isc__netievent_close_t *event =
+				isc__nm_get_netievent_close(sock->mgr, sock);
+			isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+					       (isc__netievent_t *)event);
+		}
+	}
+
+	if (handle == sock->statichandle) {
+		/* statichandle is assigned, not attached. */
+		sock->statichandle = NULL;
+	}
+
+	isc___nmsocket_detach(&sock FLARG_PASS);
+}
+
+void *
+isc_nmhandle_getdata(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	return (handle->opaque);
+}
+
+void
+isc_nmhandle_setdata(isc_nmhandle_t *handle, void *arg,
+		     isc_nm_opaquecb_t doreset, isc_nm_opaquecb_t dofree) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	handle->opaque = arg;
+	handle->doreset = doreset;
+	handle->dofree = dofree;
+}
+
+void
+isc__nm_alloc_dnsbuf(isc_nmsocket_t *sock, size_t len) {
+	REQUIRE(len <= NM_BIG_BUF);
+
+	if (sock->buf == NULL) {
+		/* We don't have the buffer at all */
+		size_t alloc_len = len < NM_REG_BUF ? NM_REG_BUF : NM_BIG_BUF;
+		sock->buf = isc_mem_allocate(sock->mgr->mctx, alloc_len);
+		sock->buf_size = alloc_len;
+	} else {
+		/* We have the buffer but it's too small */
+		sock->buf = isc_mem_reallocate(sock->mgr->mctx, sock->buf,
+					       NM_BIG_BUF);
+		sock->buf_size = NM_BIG_BUF;
+	}
+}
+
+void
+isc__nm_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_failed_accept_cb(isc_nmsocket_t *sock, isc_result_t eresult) {
+	REQUIRE(sock->accepting);
+	REQUIRE(sock->server);
+
+	/*
+	 * Detach the quota early to make room for other connections;
+	 * otherwise it'd be detached later asynchronously, and clog
+	 * the quota unnecessarily.
+	 */
+	if (sock->quota != NULL) {
+		isc_quota_detach(&sock->quota);
+	}
+
+	isc__nmsocket_detach(&sock->server);
+
+	sock->accepting = false;
+
+	switch (eresult) {
+	case ISC_R_NOTCONNECTED:
+		/* IGNORE: The client disconnected before we could accept */
+		break;
+	default:
+		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
+			      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
+			      "Accepting TCP connection failed: %s",
+			      isc_result_totext(eresult));
+	}
+}
+
+void
+isc__nm_failed_connect_cb(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
+			  isc_result_t eresult, bool async) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(req));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(req->cb.connect != NULL);
+
+	isc__nmsocket_timer_stop(sock);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+
+	INSIST(atomic_compare_exchange_strong(&sock->connecting,
+					      &(bool){ true }, false));
+
+	isc__nmsocket_clearcb(sock);
+	isc__nm_connectcb(sock, req, eresult, async);
+
+	isc__nmsocket_prep_destroy(sock);
+}
+
+void
+isc__nm_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result, bool async) {
+	REQUIRE(VALID_NMSOCK(sock));
+	UNUSED(async);
+
+	switch (sock->type) {
+	case isc_nm_udpsocket:
+		isc__nm_udp_failed_read_cb(sock, result);
+		return;
+	case isc_nm_tcpsocket:
+		isc__nm_tcp_failed_read_cb(sock, result);
+		return;
+	case isc_nm_tcpdnssocket:
+		isc__nm_tcpdns_failed_read_cb(sock, result);
+		return;
+	default:
+		UNREACHABLE();
+	}
+}
+
+void
+isc__nmsocket_connecttimeout_cb(uv_timer_t *timer) {
+	uv_connect_t *uvreq = uv_handle_get_data((uv_handle_t *)timer);
+	isc_nmsocket_t *sock = uv_handle_get_data((uv_handle_t *)uvreq->handle);
+	isc__nm_uvreq_t *req = uv_handle_get_data((uv_handle_t *)uvreq);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->connecting));
+	REQUIRE(VALID_UVREQ(req));
+	REQUIRE(VALID_NMHANDLE(req->handle));
+
+	isc__nmsocket_timer_stop(sock);
+
+	/*
+	 * Mark the connection as timed out and shutdown the socket.
+	 */
+
+	INSIST(atomic_compare_exchange_strong(&sock->timedout, &(bool){ false },
+					      true));
+	isc__nmsocket_clearcb(sock);
+	isc__nmsocket_shutdown(sock);
+}
+
+void
+isc__nm_accept_connection_log(isc_result_t result, bool can_log_quota) {
+	int level;
+
+	switch (result) {
+	case ISC_R_SUCCESS:
+	case ISC_R_NOCONN:
+		return;
+	case ISC_R_QUOTA:
+	case ISC_R_SOFTQUOTA:
+		if (!can_log_quota) {
+			return;
+		}
+		level = ISC_LOG_INFO;
+		break;
+	case ISC_R_NOTCONNECTED:
+		level = ISC_LOG_INFO;
+		break;
+	default:
+		level = ISC_LOG_ERROR;
+	}
+
+	isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL, ISC_LOGMODULE_NETMGR,
+		      level, "Accepting TCP connection failed: %s",
+		      isc_result_totext(result));
+}
+
+void
+isc__nmsocket_writetimeout_cb(void *data, isc_result_t eresult) {
+	isc__nm_uvreq_t *req = data;
+	isc_nmsocket_t *sock = NULL;
+
+	REQUIRE(eresult == ISC_R_TIMEDOUT);
+	REQUIRE(VALID_UVREQ(req));
+	REQUIRE(VALID_NMSOCK(req->sock));
+
+	sock = req->sock;
+
+	isc__nmsocket_reset(sock);
+}
+
+void
+isc__nmsocket_readtimeout_cb(uv_timer_t *timer) {
+	isc_nmsocket_t *sock = uv_handle_get_data((uv_handle_t *)timer);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->reading);
+
+	if (atomic_load(&sock->client)) {
+		uv_timer_stop(timer);
+
+		if (sock->recv_cb != NULL) {
+			isc__nm_uvreq_t *req = isc__nm_get_read_req(sock, NULL);
+			isc__nm_readcb(sock, req, ISC_R_TIMEDOUT);
+		}
+
+		if (!isc__nmsocket_timer_running(sock)) {
+			isc__nmsocket_clearcb(sock);
+			isc__nm_failed_read_cb(sock, ISC_R_CANCELED, false);
+		}
+	} else {
+		isc__nm_failed_read_cb(sock, ISC_R_TIMEDOUT, false);
+	}
+}
+
+void
+isc__nmsocket_timer_restart(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+
+	if (atomic_load(&sock->connecting)) {
+		int r;
+
+		if (sock->connect_timeout == 0) {
+			return;
+		}
+
+		r = uv_timer_start(&sock->read_timer,
+				   isc__nmsocket_connecttimeout_cb,
+				   sock->connect_timeout + 10, 0);
+		UV_RUNTIME_CHECK(uv_timer_start, r);
+
+	} else {
+		int r;
+
+		if (sock->read_timeout == 0) {
+			return;
+		}
+
+		r = uv_timer_start(&sock->read_timer,
+				   isc__nmsocket_readtimeout_cb,
+				   sock->read_timeout, 0);
+		UV_RUNTIME_CHECK(uv_timer_start, r);
+	}
+}
+
+bool
+isc__nmsocket_timer_running(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+
+	return (uv_is_active((uv_handle_t *)&sock->read_timer));
+}
+
+void
+isc__nmsocket_timer_start(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+
+	if (isc__nmsocket_timer_running(sock)) {
+		return;
+	}
+
+	isc__nmsocket_timer_restart(sock);
+}
+
+void
+isc__nmsocket_timer_stop(isc_nmsocket_t *sock) {
+	int r;
+
+	REQUIRE(VALID_NMSOCK(sock));
+
+	/* uv_timer_stop() is idempotent, no need to check if running */
+
+	r = uv_timer_stop(&sock->read_timer);
+	UV_RUNTIME_CHECK(uv_timer_stop, r);
+}
+
+isc__nm_uvreq_t *
+isc__nm_get_read_req(isc_nmsocket_t *sock, isc_sockaddr_t *sockaddr) {
+	isc__nm_uvreq_t *req = NULL;
+
+	req = isc__nm_uvreq_get(sock->mgr, sock);
+	req->cb.recv = sock->recv_cb;
+	req->cbarg = sock->recv_cbarg;
+
+	switch (sock->type) {
+	case isc_nm_tcpsocket:
+		isc_nmhandle_attach(sock->statichandle, &req->handle);
+		break;
+	default:
+		if (atomic_load(&sock->client)) {
+			isc_nmhandle_attach(sock->statichandle, &req->handle);
+		} else {
+			req->handle = isc__nmhandle_get(sock, sockaddr, NULL);
+		}
+		break;
+	}
+
+	return (req);
+}
+
+/*%<
+ * Allocator callback for read operations.
+ *
+ * Note this doesn't actually allocate anything, it just assigns the
+ * worker's receive buffer to a socket, and marks it as "in use".
+ */
+void
+isc__nm_alloc_cb(uv_handle_t *handle, size_t size, uv_buf_t *buf) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+	isc__networker_t *worker = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(isc__nm_in_netthread());
+	/*
+	 * The size provided by libuv is only suggested size, and it always
+	 * defaults to 64 * 1024 in the current versions of libuv (see
+	 * src/unix/udp.c and src/unix/stream.c).
+	 */
+	UNUSED(size);
+
+	worker = &sock->mgr->workers[sock->tid];
+	INSIST(!worker->recvbuf_inuse);
+	INSIST(worker->recvbuf != NULL);
+
+	switch (sock->type) {
+	case isc_nm_udpsocket:
+		buf->len = ISC_NETMGR_UDP_RECVBUF_SIZE;
+		break;
+	case isc_nm_tcpsocket:
+	case isc_nm_tcpdnssocket:
+		buf->len = ISC_NETMGR_TCP_RECVBUF_SIZE;
+		break;
+	default:
+		UNREACHABLE();
+	}
+
+	REQUIRE(buf->len <= ISC_NETMGR_RECVBUF_SIZE);
+	buf->base = worker->recvbuf;
+
+	worker->recvbuf_inuse = true;
+}
+
+isc_result_t
+isc__nm_start_reading(isc_nmsocket_t *sock) {
+	isc_result_t result = ISC_R_SUCCESS;
+	int r;
+
+	if (sock->reading) {
+		return (ISC_R_SUCCESS);
+	}
+
+	switch (sock->type) {
+	case isc_nm_udpsocket:
+		r = uv_udp_recv_start(&sock->uv_handle.udp, isc__nm_alloc_cb,
+				      isc__nm_udp_read_cb);
+		break;
+	case isc_nm_tcpsocket:
+		r = uv_read_start(&sock->uv_handle.stream, isc__nm_alloc_cb,
+				  isc__nm_tcp_read_cb);
+		break;
+	case isc_nm_tcpdnssocket:
+		r = uv_read_start(&sock->uv_handle.stream, isc__nm_alloc_cb,
+				  isc__nm_tcpdns_read_cb);
+		break;
+	default:
+		UNREACHABLE();
+	}
+
+	if (r != 0) {
+		result = isc__nm_uverr2result(r);
+	} else {
+		sock->reading = true;
+	}
+
+	return (result);
+}
+
+void
+isc__nm_stop_reading(isc_nmsocket_t *sock) {
+	int r;
+
+	if (!sock->reading) {
+		return;
+	}
+
+	switch (sock->type) {
+	case isc_nm_udpsocket:
+		r = uv_udp_recv_stop(&sock->uv_handle.udp);
+		UV_RUNTIME_CHECK(uv_udp_recv_stop, r);
+		break;
+	case isc_nm_tcpsocket:
+	case isc_nm_tcpdnssocket:
+		r = uv_read_stop(&sock->uv_handle.stream);
+		UV_RUNTIME_CHECK(uv_read_stop, r);
+		break;
+	default:
+		UNREACHABLE();
+	}
+	sock->reading = false;
+}
+
+bool
+isc__nm_closing(isc_nmsocket_t *sock) {
+	return (atomic_load(&sock->mgr->closing));
+}
+
+bool
+isc__nmsocket_closing(isc_nmsocket_t *sock) {
+	return (!isc__nmsocket_active(sock) || atomic_load(&sock->closing) ||
+		atomic_load(&sock->mgr->closing) ||
+		(sock->server != NULL && !isc__nmsocket_active(sock->server)));
+}
+
+static isc_result_t
+processbuffer(isc_nmsocket_t *sock) {
+	switch (sock->type) {
+	case isc_nm_tcpdnssocket:
+		return (isc__nm_tcpdns_processbuffer(sock));
+	default:
+		UNREACHABLE();
+	}
+}
+
+/*
+ * Process a DNS message.
+ *
+ * If we only have an incomplete DNS message, we don't touch any
+ * timers. If we do have a full message, reset the timer.
+ *
+ * Stop reading if this is a client socket, or if the server socket
+ * has been set to sequential mode, or the number of queries we are
+ * processing simultaneously has reached the clients-per-connection
+ * limit. In this case we'll be called again by resume_processing()
+ * later.
+ */
+isc_result_t
+isc__nm_process_sock_buffer(isc_nmsocket_t *sock) {
+	for (;;) {
+		int_fast32_t ah = atomic_load(&sock->ah);
+		isc_result_t result = processbuffer(sock);
+		switch (result) {
+		case ISC_R_NOMORE:
+			/*
+			 * Don't reset the timer until we have a
+			 * full DNS message.
+			 */
+			result = isc__nm_start_reading(sock);
+			if (result != ISC_R_SUCCESS) {
+				return (result);
+			}
+			/*
+			 * Start the timer only if there are no externally used
+			 * active handles, there's always one active handle
+			 * attached internally to sock->recv_handle in
+			 * accept_connection()
+			 */
+			if (ah == 1) {
+				isc__nmsocket_timer_start(sock);
+			}
+			goto done;
+		case ISC_R_CANCELED:
+			isc__nmsocket_timer_stop(sock);
+			isc__nm_stop_reading(sock);
+			goto done;
+		case ISC_R_SUCCESS:
+			/*
+			 * Stop the timer on the successful message read, this
+			 * also allows to restart the timer when we have no more
+			 * data.
+			 */
+			isc__nmsocket_timer_stop(sock);
+
+			if (atomic_load(&sock->client) ||
+			    atomic_load(&sock->sequential) ||
+			    ah >= STREAM_CLIENTS_PER_CONN)
+			{
+				isc__nm_stop_reading(sock);
+				goto done;
+			}
+			break;
+		default:
+			UNREACHABLE();
+		}
+	}
+done:
+	return (ISC_R_SUCCESS);
+}
+
+void
+isc__nm_resume_processing(void *arg) {
+	isc_nmsocket_t *sock = (isc_nmsocket_t *)arg;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(!atomic_load(&sock->client));
+
+	if (isc__nmsocket_closing(sock)) {
+		return;
+	}
+
+	isc__nm_process_sock_buffer(sock);
+}
+
+void
+isc_nmhandle_cleartimeout(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	switch (handle->sock->type) {
+	default:
+		handle->sock->read_timeout = 0;
+
+		if (uv_is_active((uv_handle_t *)&handle->sock->read_timer)) {
+			isc__nmsocket_timer_stop(handle->sock);
+		}
+	}
+}
+
+void
+isc_nmhandle_settimeout(isc_nmhandle_t *handle, uint32_t timeout) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	switch (handle->sock->type) {
+	default:
+		handle->sock->read_timeout = timeout;
+		isc__nmsocket_timer_restart(handle->sock);
+	}
+}
+
+void
+isc_nmhandle_keepalive(isc_nmhandle_t *handle, bool value) {
+	isc_nmsocket_t *sock = NULL;
+
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	sock = handle->sock;
+
+	switch (sock->type) {
+	case isc_nm_tcpsocket:
+	case isc_nm_tcpdnssocket:
+		atomic_store(&sock->keepalive, value);
+		sock->read_timeout = value ? atomic_load(&sock->mgr->keepalive)
+					   : atomic_load(&sock->mgr->idle);
+		sock->write_timeout = value ? atomic_load(&sock->mgr->keepalive)
+					    : atomic_load(&sock->mgr->idle);
+		break;
+	default:
+		/*
+		 * For any other protocol, this is a no-op.
+		 */
+		return;
+	}
+}
+
+void *
+isc_nmhandle_getextra(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	return (handle->extra);
+}
+
+isc_sockaddr_t
+isc_nmhandle_peeraddr(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	return (handle->peer);
+}
+
+isc_sockaddr_t
+isc_nmhandle_localaddr(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	return (handle->local);
+}
+
+isc_nm_t *
+isc_nmhandle_netmgr(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	return (handle->sock->mgr);
+}
+
+isc__nm_uvreq_t *
+isc___nm_uvreq_get(isc_nm_t *mgr, isc_nmsocket_t *sock FLARG) {
+	isc__nm_uvreq_t *req = NULL;
+
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(VALID_NMSOCK(sock));
+
+	if (sock != NULL && isc__nmsocket_active(sock)) {
+		/* Try to reuse one */
+		req = isc_astack_pop(sock->inactivereqs);
+	}
+
+	if (req == NULL) {
+		req = isc_mem_get(mgr->mctx, sizeof(*req));
+	}
+
+	*req = (isc__nm_uvreq_t){ .magic = 0 };
+	ISC_LINK_INIT(req, link);
+	req->uv_req.req.data = req;
+	isc___nmsocket_attach(sock, &req->sock FLARG_PASS);
+	req->magic = UVREQ_MAGIC;
+
+	return (req);
+}
+
+void
+isc___nm_uvreq_put(isc__nm_uvreq_t **req0, isc_nmsocket_t *sock FLARG) {
+	isc__nm_uvreq_t *req = NULL;
+	isc_nmhandle_t *handle = NULL;
+
+	REQUIRE(req0 != NULL);
+	REQUIRE(VALID_UVREQ(*req0));
+
+	req = *req0;
+	*req0 = NULL;
+
+	INSIST(sock == req->sock);
+
+	req->magic = 0;
+
+	/*
+	 * We need to save this first to make sure that handle,
+	 * sock, and the netmgr won't all disappear.
+	 */
+	handle = req->handle;
+	req->handle = NULL;
+
+#if !__SANITIZE_ADDRESS__ && !__SANITIZE_THREAD__
+	if (!isc__nmsocket_active(sock) ||
+	    !isc_astack_trypush(sock->inactivereqs, req))
+	{
+		isc_mem_put(sock->mgr->mctx, req, sizeof(*req));
+	}
+#else  /* !__SANITIZE_ADDRESS__ && !__SANITIZE_THREAD__ */
+	isc_mem_put(sock->mgr->mctx, req, sizeof(*req));
+#endif /* !__SANITIZE_ADDRESS__ && !__SANITIZE_THREAD__ */
+
+	if (handle != NULL) {
+		isc__nmhandle_detach(&handle FLARG_PASS);
+	}
+
+	isc___nmsocket_detach(&sock FLARG_PASS);
+}
+
+void
+isc_nm_send(isc_nmhandle_t *handle, isc_region_t *region, isc_nm_cb_t cb,
+	    void *cbarg) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	switch (handle->sock->type) {
+	case isc_nm_udpsocket:
+	case isc_nm_udplistener:
+		isc__nm_udp_send(handle, region, cb, cbarg);
+		break;
+	case isc_nm_tcpsocket:
+		isc__nm_tcp_send(handle, region, cb, cbarg);
+		break;
+	case isc_nm_tcpdnssocket:
+		isc__nm_tcpdns_send(handle, region, cb, cbarg);
+		break;
+	default:
+		UNREACHABLE();
+	}
+}
+
+void
+isc_nm_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	/*
+	 * This is always called via callback (from accept or connect), and
+	 * caller must attach to the handle, so the references always need to be
+	 * at least 2.
+	 */
+	REQUIRE(isc_refcount_current(&handle->references) >= 2);
+
+	switch (handle->sock->type) {
+	case isc_nm_udpsocket:
+		isc__nm_udp_read(handle, cb, cbarg);
+		break;
+	case isc_nm_tcpsocket:
+		isc__nm_tcp_read(handle, cb, cbarg);
+		break;
+	case isc_nm_tcpdnssocket:
+		isc__nm_tcpdns_read(handle, cb, cbarg);
+		break;
+	default:
+		UNREACHABLE();
+	}
+}
+
+void
+isc_nm_cancelread(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	switch (handle->sock->type) {
+	case isc_nm_udpsocket:
+		isc__nm_udp_cancelread(handle);
+		break;
+	case isc_nm_tcpsocket:
+		isc__nm_tcp_cancelread(handle);
+		break;
+	case isc_nm_tcpdnssocket:
+		isc__nm_tcpdns_cancelread(handle);
+		break;
+	default:
+		UNREACHABLE();
+	}
+}
+
+void
+isc_nm_pauseread(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	isc_nmsocket_t *sock = handle->sock;
+
+	switch (sock->type) {
+	case isc_nm_tcpsocket:
+		isc__nm_tcp_pauseread(handle);
+		break;
+	default:
+		UNREACHABLE();
+	}
+}
+
+void
+isc_nm_resumeread(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	isc_nmsocket_t *sock = handle->sock;
+
+	switch (sock->type) {
+	case isc_nm_tcpsocket:
+		isc__nm_tcp_resumeread(handle);
+		break;
+	default:
+		UNREACHABLE();
+	}
+}
+
+void
+isc_nm_stoplistening(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+
+	switch (sock->type) {
+	case isc_nm_udplistener:
+		isc__nm_udp_stoplistening(sock);
+		break;
+	case isc_nm_tcpdnslistener:
+		isc__nm_tcpdns_stoplistening(sock);
+		break;
+	case isc_nm_tcplistener:
+		isc__nm_tcp_stoplistening(sock);
+		break;
+	default:
+		UNREACHABLE();
+	}
+}
+
+void
+isc__nm_connectcb(isc_nmsocket_t *sock, isc__nm_uvreq_t *uvreq,
+		  isc_result_t eresult, bool async) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(uvreq));
+	REQUIRE(VALID_NMHANDLE(uvreq->handle));
+
+	if (!async) {
+		isc__netievent_connectcb_t ievent = { .sock = sock,
+						      .req = uvreq,
+						      .result = eresult };
+		isc__nm_async_connectcb(NULL, (isc__netievent_t *)&ievent);
+	} else {
+		isc__netievent_connectcb_t *ievent =
+			isc__nm_get_netievent_connectcb(sock->mgr, sock, uvreq,
+							eresult);
+		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+}
+
+void
+isc__nm_async_connectcb(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_connectcb_t *ievent = (isc__netievent_connectcb_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc__nm_uvreq_t *uvreq = ievent->req;
+	isc_result_t eresult = ievent->result;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(uvreq));
+	REQUIRE(VALID_NMHANDLE(uvreq->handle));
+	REQUIRE(ievent->sock->tid == isc_nm_tid());
+	REQUIRE(uvreq->cb.connect != NULL);
+
+	uvreq->cb.connect(uvreq->handle, eresult, uvreq->cbarg);
+
+	isc__nm_uvreq_put(&uvreq, sock);
+}
+
+void
+isc__nm_readcb(isc_nmsocket_t *sock, isc__nm_uvreq_t *uvreq,
+	       isc_result_t eresult) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(uvreq));
+	REQUIRE(VALID_NMHANDLE(uvreq->handle));
+
+	if (eresult == ISC_R_SUCCESS || eresult == ISC_R_TIMEDOUT) {
+		isc__netievent_readcb_t ievent = { .sock = sock,
+						   .req = uvreq,
+						   .result = eresult };
+
+		isc__nm_async_readcb(NULL, (isc__netievent_t *)&ievent);
+	} else {
+		isc__netievent_readcb_t *ievent = isc__nm_get_netievent_readcb(
+			sock->mgr, sock, uvreq, eresult);
+		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+}
+
+void
+isc__nm_async_readcb(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_readcb_t *ievent = (isc__netievent_readcb_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc__nm_uvreq_t *uvreq = ievent->req;
+	isc_result_t eresult = ievent->result;
+	isc_region_t region;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(uvreq));
+	REQUIRE(VALID_NMHANDLE(uvreq->handle));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	region.base = (unsigned char *)uvreq->uvbuf.base;
+	region.length = uvreq->uvbuf.len;
+
+	uvreq->cb.recv(uvreq->handle, eresult, &region, uvreq->cbarg);
+
+	isc__nm_uvreq_put(&uvreq, sock);
+}
+
+void
+isc__nm_sendcb(isc_nmsocket_t *sock, isc__nm_uvreq_t *uvreq,
+	       isc_result_t eresult, bool async) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(uvreq));
+	REQUIRE(VALID_NMHANDLE(uvreq->handle));
+
+	if (!async) {
+		isc__netievent_sendcb_t ievent = { .sock = sock,
+						   .req = uvreq,
+						   .result = eresult };
+		isc__nm_async_sendcb(NULL, (isc__netievent_t *)&ievent);
+		return;
+	}
+
+	isc__netievent_sendcb_t *ievent =
+		isc__nm_get_netievent_sendcb(sock->mgr, sock, uvreq, eresult);
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+}
+
+void
+isc__nm_async_sendcb(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_sendcb_t *ievent = (isc__netievent_sendcb_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc__nm_uvreq_t *uvreq = ievent->req;
+	isc_result_t eresult = ievent->result;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(uvreq));
+	REQUIRE(VALID_NMHANDLE(uvreq->handle));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	uvreq->cb.send(uvreq->handle, eresult, uvreq->cbarg);
+
+	isc__nm_uvreq_put(&uvreq, sock);
+}
+
+static void
+isc__nm_async_close(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_close_t *ievent = (isc__netievent_close_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	REQUIRE(VALID_NMSOCK(ievent->sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->closehandle_cb != NULL);
+
+	UNUSED(worker);
+
+	ievent->sock->closehandle_cb(sock);
+}
+
+void
+isc__nm_async_detach(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_detach_t *ievent = (isc__netievent_detach_t *)ev0;
+	FLARG_IEVENT(ievent);
+
+	REQUIRE(VALID_NMSOCK(ievent->sock));
+	REQUIRE(VALID_NMHANDLE(ievent->handle));
+	REQUIRE(ievent->sock->tid == isc_nm_tid());
+
+	UNUSED(worker);
+
+	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));
+
+	switch (sock->type) {
+	case isc_nm_tcpsocket:
+	case isc_nm_tcpdnssocket:
+		/*
+		 * This can be called from the TCP write timeout.
+		 */
+		REQUIRE(sock->parent == NULL);
+		break;
+	default:
+		UNREACHABLE();
+		break;
+	}
+
+	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.
+		 */
+		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);
+	}
+}
+
+void
+isc__nmsocket_shutdown(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	switch (sock->type) {
+	case isc_nm_udpsocket:
+		isc__nm_udp_shutdown(sock);
+		break;
+	case isc_nm_tcpsocket:
+		isc__nm_tcp_shutdown(sock);
+		break;
+	case isc_nm_tcpdnssocket:
+		isc__nm_tcpdns_shutdown(sock);
+		break;
+	case isc_nm_udplistener:
+	case isc_nm_tcplistener:
+	case isc_nm_tcpdnslistener:
+		return;
+	default:
+		UNREACHABLE();
+	}
+}
+
+static void
+shutdown_walk_cb(uv_handle_t *handle, void *arg) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+	UNUSED(arg);
+
+	if (uv_is_closing(handle)) {
+		return;
+	}
+
+	switch (handle->type) {
+	case UV_UDP:
+		isc__nmsocket_shutdown(sock);
+		return;
+	case UV_TCP:
+		switch (sock->type) {
+		case isc_nm_tcpsocket:
+		case isc_nm_tcpdnssocket:
+			if (sock->parent == NULL) {
+				/* Reset the TCP connections on shutdown */
+				isc__nmsocket_reset(sock);
+				return;
+			}
+			FALLTHROUGH;
+		default:
+			isc__nmsocket_shutdown(sock);
+		}
+
+		return;
+	default:
+		return;
+	}
+}
+
+void
+isc__nm_async_shutdown(isc__networker_t *worker, isc__netievent_t *ev0) {
+	UNUSED(ev0);
+
+	uv_walk(&worker->loop, shutdown_walk_cb, NULL);
+}
+
+bool
+isc__nm_acquire_interlocked(isc_nm_t *mgr) {
+	if (!isc__nm_in_netthread()) {
+		return (false);
+	}
+
+	LOCK(&mgr->lock);
+	bool success = atomic_compare_exchange_strong(
+		&mgr->interlocked, &(int){ ISC_NETMGR_NON_INTERLOCKED },
+		isc_nm_tid());
+
+	UNLOCK(&mgr->lock);
+	return (success);
+}
+
+void
+isc__nm_drop_interlocked(isc_nm_t *mgr) {
+	if (!isc__nm_in_netthread()) {
+		return;
+	}
+
+	LOCK(&mgr->lock);
+	int tid = atomic_exchange(&mgr->interlocked,
+				  ISC_NETMGR_NON_INTERLOCKED);
+	INSIST(tid != ISC_NETMGR_NON_INTERLOCKED);
+	BROADCAST(&mgr->wkstatecond);
+	UNLOCK(&mgr->lock);
+}
+
+void
+isc__nm_acquire_interlocked_force(isc_nm_t *mgr) {
+	if (!isc__nm_in_netthread()) {
+		return;
+	}
+
+	LOCK(&mgr->lock);
+	while (!atomic_compare_exchange_strong(
+		&mgr->interlocked, &(int){ ISC_NETMGR_NON_INTERLOCKED },
+		isc_nm_tid()))
+	{
+		WAIT(&mgr->wkstatecond, &mgr->lock);
+	}
+	UNLOCK(&mgr->lock);
+}
+
+void
+isc_nm_setstats(isc_nm_t *mgr, isc_stats_t *stats) {
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(mgr->stats == NULL);
+	REQUIRE(isc_stats_ncounters(stats) == isc_sockstatscounter_max);
+
+	isc_stats_attach(stats, &mgr->stats);
+}
+
+void
+isc__nm_incstats(isc_nm_t *mgr, isc_statscounter_t counterid) {
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(counterid != -1);
+
+	if (mgr->stats != NULL) {
+		isc_stats_increment(mgr->stats, counterid);
+	}
+}
+
+void
+isc__nm_decstats(isc_nm_t *mgr, isc_statscounter_t counterid) {
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(counterid != -1);
+
+	if (mgr->stats != NULL) {
+		isc_stats_decrement(mgr->stats, counterid);
+	}
+}
+
+isc_result_t
+isc__nm_socket(int domain, int type, int protocol, uv_os_sock_t *sockp) {
+#ifdef WIN32
+	SOCKET sock;
+	sock = socket(domain, type, protocol);
+	if (sock == INVALID_SOCKET) {
+		char strbuf[ISC_STRERRORSIZE];
+		DWORD socket_errno = WSAGetLastError();
+		switch (socket_errno) {
+		case WSAEMFILE:
+		case WSAENOBUFS:
+			return (ISC_R_NORESOURCES);
+
+		case WSAEPROTONOSUPPORT:
+		case WSAEPFNOSUPPORT:
+		case WSAEAFNOSUPPORT:
+			return (ISC_R_FAMILYNOSUPPORT);
+		default:
+			strerror_r(socket_errno, strbuf, sizeof(strbuf));
+			UNEXPECTED_ERROR(
+				__FILE__, __LINE__,
+				"socket() failed with error code %lu: %s",
+				socket_errno, strbuf);
+			return (ISC_R_UNEXPECTED);
+		}
+	}
+#else
+	int sock = socket(domain, type, protocol);
+	if (sock < 0) {
+		return (isc_errno_toresult(errno));
+	}
+#endif
+	*sockp = (uv_os_sock_t)sock;
+	return (ISC_R_SUCCESS);
+}
+
+void
+isc__nm_closesocket(uv_os_sock_t sock) {
+#ifdef WIN32
+	closesocket(sock);
+#else
+	close(sock);
+#endif
+}
+
+#define setsockopt_on(socket, level, name) \
+	setsockopt(socket, level, name, &(int){ 1 }, sizeof(int))
+
+#define setsockopt_off(socket, level, name) \
+	setsockopt(socket, level, name, &(int){ 0 }, sizeof(int))
+
+isc_result_t
+isc__nm_socket_freebind(uv_os_sock_t fd, sa_family_t sa_family) {
+	/*
+	 * Set the IP_FREEBIND (or equivalent option) on the uv_handle.
+	 */
+#ifdef IP_FREEBIND
+	UNUSED(sa_family);
+	if (setsockopt_on(fd, IPPROTO_IP, IP_FREEBIND) == -1) {
+		return (ISC_R_FAILURE);
+	}
+	return (ISC_R_SUCCESS);
+#elif defined(IP_BINDANY) || defined(IPV6_BINDANY)
+	if (sa_family == AF_INET) {
+#if defined(IP_BINDANY)
+		if (setsockopt_on(fd, IPPROTO_IP, IP_BINDANY) == -1) {
+			return (ISC_R_FAILURE);
+		}
+		return (ISC_R_SUCCESS);
+#endif
+	} else if (sa_family == AF_INET6) {
+#if defined(IPV6_BINDANY)
+		if (setsockopt_on(fd, IPPROTO_IPV6, IPV6_BINDANY) == -1) {
+			return (ISC_R_FAILURE);
+		}
+		return (ISC_R_SUCCESS);
+#endif
+	}
+	return (ISC_R_NOTIMPLEMENTED);
+#elif defined(SO_BINDANY)
+	UNUSED(sa_family);
+	if (setsockopt_on(fd, SOL_SOCKET, SO_BINDANY) == -1) {
+		return (ISC_R_FAILURE);
+	}
+	return (ISC_R_SUCCESS);
+#else
+	UNUSED(fd);
+	UNUSED(sa_family);
+	return (ISC_R_NOTIMPLEMENTED);
+#endif
+}
+
+isc_result_t
+isc__nm_socket_reuse(uv_os_sock_t fd) {
+	/*
+	 * Generally, the SO_REUSEADDR socket option allows reuse of
+	 * local addresses.
+	 *
+	 * On the BSDs, SO_REUSEPORT implies SO_REUSEADDR but with some
+	 * additional refinements for programs that use multicast.
+	 *
+	 * On Linux, SO_REUSEPORT has different semantics: it _shares_ the port
+	 * rather than steal it from the current listener, so we don't use it
+	 * here, but rather in isc__nm_socket_reuse_lb().
+	 *
+	 * On Windows, it also allows a socket to forcibly bind to a port in use
+	 * by another socket.
+	 */
+
+#if defined(SO_REUSEPORT) && !defined(__linux__)
+	if (setsockopt_on(fd, SOL_SOCKET, SO_REUSEPORT) == -1) {
+		return (ISC_R_FAILURE);
+	}
+	return (ISC_R_SUCCESS);
+#elif defined(SO_REUSEADDR)
+	if (setsockopt_on(fd, SOL_SOCKET, SO_REUSEADDR) == -1) {
+		return (ISC_R_FAILURE);
+	}
+	return (ISC_R_SUCCESS);
+#else
+	UNUSED(fd);
+	return (ISC_R_NOTIMPLEMENTED);
+#endif
+}
+
+isc_result_t
+isc__nm_socket_reuse_lb(uv_os_sock_t fd) {
+	/*
+	 * On FreeBSD 12+, SO_REUSEPORT_LB socket option allows sockets to be
+	 * bound to an identical socket address. For UDP sockets, the use of
+	 * this option can provide better distribution of incoming datagrams to
+	 * multiple processes (or threads) as compared to the traditional
+	 * technique of having multiple processes compete to receive datagrams
+	 * on the same socket.
+	 *
+	 * On Linux, the same thing is achieved simply with SO_REUSEPORT.
+	 */
+#if defined(SO_REUSEPORT_LB)
+	if (setsockopt_on(fd, SOL_SOCKET, SO_REUSEPORT_LB) == -1) {
+		return (ISC_R_FAILURE);
+	} else {
+		return (ISC_R_SUCCESS);
+	}
+#elif defined(SO_REUSEPORT) && defined(__linux__)
+	if (setsockopt_on(fd, SOL_SOCKET, SO_REUSEPORT) == -1) {
+		return (ISC_R_FAILURE);
+	} else {
+		return (ISC_R_SUCCESS);
+	}
+#else
+	UNUSED(fd);
+	return (ISC_R_NOTIMPLEMENTED);
+#endif
+}
+
+isc_result_t
+isc__nm_socket_incoming_cpu(uv_os_sock_t fd) {
+#ifdef SO_INCOMING_CPU
+	if (setsockopt_on(fd, SOL_SOCKET, SO_INCOMING_CPU) == -1) {
+		return (ISC_R_FAILURE);
+	} else {
+		return (ISC_R_SUCCESS);
+	}
+#else
+	UNUSED(fd);
+#endif
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+isc_result_t
+isc__nm_socket_disable_pmtud(uv_os_sock_t fd, sa_family_t sa_family) {
+	/*
+	 * Disable the Path MTU Discovery on IP packets
+	 */
+	if (sa_family == AF_INET6) {
+#if defined(IPV6_DONTFRAG)
+		if (setsockopt_off(fd, IPPROTO_IPV6, IPV6_DONTFRAG) == -1) {
+			return (ISC_R_FAILURE);
+		} else {
+			return (ISC_R_SUCCESS);
+		}
+#elif defined(IPV6_MTU_DISCOVER) && defined(IP_PMTUDISC_OMIT)
+		if (setsockopt(fd, IPPROTO_IPV6, IPV6_MTU_DISCOVER,
+			       &(int){ IP_PMTUDISC_OMIT }, sizeof(int)) == -1)
+		{
+			return (ISC_R_FAILURE);
+		} else {
+			return (ISC_R_SUCCESS);
+		}
+#else
+		UNUSED(fd);
+#endif
+	} else if (sa_family == AF_INET) {
+#if defined(IP_DONTFRAG)
+		if (setsockopt_off(fd, IPPROTO_IP, IP_DONTFRAG) == -1) {
+			return (ISC_R_FAILURE);
+		} else {
+			return (ISC_R_SUCCESS);
+		}
+#elif defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_OMIT)
+		if (setsockopt(fd, IPPROTO_IP, IP_MTU_DISCOVER,
+			       &(int){ IP_PMTUDISC_OMIT }, sizeof(int)) == -1)
+		{
+			return (ISC_R_FAILURE);
+		} else {
+			return (ISC_R_SUCCESS);
+		}
+#else
+		UNUSED(fd);
+#endif
+	} else {
+		return (ISC_R_FAMILYNOSUPPORT);
+	}
+
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+#if defined(_WIN32)
+#define TIMEOUT_TYPE	DWORD
+#define TIMEOUT_DIV	1000
+#define TIMEOUT_OPTNAME TCP_MAXRT
+#elif defined(TCP_CONNECTIONTIMEOUT)
+#define TIMEOUT_TYPE	int
+#define TIMEOUT_DIV	1000
+#define TIMEOUT_OPTNAME TCP_CONNECTIONTIMEOUT
+#elif defined(TCP_RXT_CONNDROPTIME)
+#define TIMEOUT_TYPE	int
+#define TIMEOUT_DIV	1000
+#define TIMEOUT_OPTNAME TCP_RXT_CONNDROPTIME
+#elif defined(TCP_USER_TIMEOUT)
+#define TIMEOUT_TYPE	unsigned int
+#define TIMEOUT_DIV	1
+#define TIMEOUT_OPTNAME TCP_USER_TIMEOUT
+#elif defined(TCP_KEEPINIT)
+#define TIMEOUT_TYPE	int
+#define TIMEOUT_DIV	1000
+#define TIMEOUT_OPTNAME TCP_KEEPINIT
+#endif
+
+isc_result_t
+isc__nm_socket_connectiontimeout(uv_os_sock_t fd, int timeout_ms) {
+#if defined(TIMEOUT_OPTNAME)
+	TIMEOUT_TYPE timeout = timeout_ms / TIMEOUT_DIV;
+
+	if (timeout == 0) {
+		timeout = 1;
+	}
+
+	if (setsockopt(fd, IPPROTO_TCP, TIMEOUT_OPTNAME, &timeout,
+		       sizeof(timeout)) == -1)
+	{
+		return (ISC_R_FAILURE);
+	}
+
+	return (ISC_R_SUCCESS);
+#else
+	UNUSED(fd);
+	UNUSED(timeout_ms);
+
+	return (ISC_R_SUCCESS);
+#endif
+}
+
+isc_result_t
+isc__nm_socket_tcp_nodelay(uv_os_sock_t fd) {
+#ifdef TCP_NODELAY
+	if (setsockopt_on(fd, IPPROTO_TCP, TCP_NODELAY) == -1) {
+		return (ISC_R_FAILURE);
+	} else {
+		return (ISC_R_SUCCESS);
+	}
+#else
+	UNUSED(fd);
+	return (ISC_R_SUCCESS);
+#endif
+}
+
+static isc_threadresult_t
+isc__nm_work_run(isc_threadarg_t arg) {
+	isc__nm_work_t *work = (isc__nm_work_t *)arg;
+
+	work->cb(work->data);
+
+	return ((isc_threadresult_t)0);
+}
+
+static void
+isc__nm_work_cb(uv_work_t *req) {
+	isc__nm_work_t *work = uv_req_get_data((uv_req_t *)req);
+
+	if (isc_tid_v == SIZE_MAX) {
+		isc__trampoline_t *trampoline_arg =
+			isc__trampoline_get(isc__nm_work_run, work);
+		(void)isc__trampoline_run(trampoline_arg);
+	} else {
+		(void)isc__nm_work_run((isc_threadarg_t)work);
+	}
+}
+
+static void
+isc__nm_after_work_cb(uv_work_t *req, int status) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc__nm_work_t *work = uv_req_get_data((uv_req_t *)req);
+	isc_nm_t *netmgr = work->netmgr;
+
+	if (status != 0) {
+		result = isc__nm_uverr2result(status);
+	}
+
+	work->after_cb(work->data, result);
+
+	isc_mem_put(netmgr->mctx, work, sizeof(*work));
+
+	isc_nm_detach(&netmgr);
+}
+
+void
+isc_nm_work_offload(isc_nm_t *netmgr, isc_nm_workcb_t work_cb,
+		    isc_nm_after_workcb_t after_work_cb, void *data) {
+	isc__networker_t *worker = NULL;
+	isc__nm_work_t *work = NULL;
+	int r;
+
+	REQUIRE(isc__nm_in_netthread());
+	REQUIRE(VALID_NM(netmgr));
+
+	worker = &netmgr->workers[isc_nm_tid()];
+
+	work = isc_mem_get(netmgr->mctx, sizeof(*work));
+	*work = (isc__nm_work_t){
+		.cb = work_cb,
+		.after_cb = after_work_cb,
+		.data = data,
+	};
+
+	isc_nm_attach(netmgr, &work->netmgr);
+
+	uv_req_set_data((uv_req_t *)&work->req, work);
+
+	r = uv_queue_work(&worker->loop, &work->req, isc__nm_work_cb,
+			  isc__nm_after_work_cb);
+	UV_RUNTIME_CHECK(uv_queue_work, r);
+}
+
+void
+isc_nm_timer_create(isc_nmhandle_t *handle, isc_nm_timer_cb cb, void *cbarg,
+		    isc_nm_timer_t **timerp) {
+	isc__networker_t *worker = NULL;
+	isc_nmsocket_t *sock = NULL;
+	isc_nm_timer_t *timer = NULL;
+	int r;
+
+	REQUIRE(isc__nm_in_netthread());
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	sock = handle->sock;
+	worker = &sock->mgr->workers[isc_nm_tid()];
+
+	timer = isc_mem_get(sock->mgr->mctx, sizeof(*timer));
+	*timer = (isc_nm_timer_t){ .cb = cb, .cbarg = cbarg };
+	isc_refcount_init(&timer->references, 1);
+	isc_nmhandle_attach(handle, &timer->handle);
+
+	r = uv_timer_init(&worker->loop, &timer->timer);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
+
+	uv_handle_set_data((uv_handle_t *)&timer->timer, timer);
+
+	*timerp = timer;
+}
+
+void
+isc_nm_timer_attach(isc_nm_timer_t *timer, isc_nm_timer_t **timerp) {
+	REQUIRE(timer != NULL);
+	REQUIRE(timerp != NULL && *timerp == NULL);
+
+	isc_refcount_increment(&timer->references);
+	*timerp = timer;
+}
+
+static void
+timer_destroy(uv_handle_t *uvhandle) {
+	isc_nm_timer_t *timer = uv_handle_get_data(uvhandle);
+	isc_nmhandle_t *handle = timer->handle;
+	isc_mem_t *mctx = timer->handle->sock->mgr->mctx;
+
+	isc_mem_put(mctx, timer, sizeof(*timer));
+
+	isc_nmhandle_detach(&handle);
+}
+
+void
+isc_nm_timer_detach(isc_nm_timer_t **timerp) {
+	isc_nm_timer_t *timer = NULL;
+	isc_nmhandle_t *handle = NULL;
+
+	REQUIRE(timerp != NULL && *timerp != NULL);
+
+	timer = *timerp;
+	*timerp = NULL;
+
+	handle = timer->handle;
+
+	REQUIRE(isc__nm_in_netthread());
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	if (isc_refcount_decrement(&timer->references) == 1) {
+		int r = uv_timer_stop(&timer->timer);
+		UV_RUNTIME_CHECK(uv_timer_stop, r);
+		uv_close((uv_handle_t *)&timer->timer, timer_destroy);
+	}
+}
+
+static void
+timer_cb(uv_timer_t *uvtimer) {
+	isc_nm_timer_t *timer = uv_handle_get_data((uv_handle_t *)uvtimer);
+
+	REQUIRE(timer->cb != NULL);
+
+	timer->cb(timer->cbarg, ISC_R_TIMEDOUT);
+}
+
+void
+isc_nm_timer_start(isc_nm_timer_t *timer, uint64_t timeout) {
+	int r = uv_timer_start(&timer->timer, timer_cb, timeout, 0);
+	UV_RUNTIME_CHECK(uv_timer_start, r);
+}
+
+void
+isc_nm_timer_stop(isc_nm_timer_t *timer) {
+	int r = uv_timer_stop(&timer->timer);
+	UV_RUNTIME_CHECK(uv_timer_stop, r);
+}
+
+#ifdef NETMGR_TRACE
+/*
+ * Dump all active sockets in netmgr. We output to stderr
+ * as the logger might be already shut down.
+ */
+
+static const char *
+nmsocket_type_totext(isc_nmsocket_type type) {
+	switch (type) {
+	case isc_nm_udpsocket:
+		return ("isc_nm_udpsocket");
+	case isc_nm_udplistener:
+		return ("isc_nm_udplistener");
+	case isc_nm_tcpsocket:
+		return ("isc_nm_tcpsocket");
+	case isc_nm_tcplistener:
+		return ("isc_nm_tcplistener");
+	case isc_nm_tcpdnslistener:
+		return ("isc_nm_tcpdnslistener");
+	case isc_nm_tcpdnssocket:
+		return ("isc_nm_tcpdnssocket");
+	default:
+		UNREACHABLE();
+	}
+}
+
+static void
+nmhandle_dump(isc_nmhandle_t *handle) {
+	fprintf(stderr, "Active handle %p, refs %" PRIuFAST32 "\n", handle,
+		isc_refcount_current(&handle->references));
+	fprintf(stderr, "Created by:\n");
+	backtrace_symbols_fd(handle->backtrace, handle->backtrace_size,
+			     STDERR_FILENO);
+	fprintf(stderr, "\n\n");
+}
+
+static void
+nmsocket_dump(isc_nmsocket_t *sock) {
+	isc_nmhandle_t *handle = NULL;
+
+	LOCK(&sock->lock);
+	fprintf(stderr, "\n=================\n");
+	fprintf(stderr, "Active %s socket %p, type %s, refs %" PRIuFAST32 "\n",
+		atomic_load(&sock->client) ? "client" : "server", sock,
+		nmsocket_type_totext(sock->type),
+		isc_refcount_current(&sock->references));
+	fprintf(stderr,
+		"Parent %p, listener %p, server %p, statichandle = "
+		"%p\n",
+		sock->parent, sock->listener, sock->server, sock->statichandle);
+	fprintf(stderr, "Flags:%s%s%s%s%s\n",
+		atomic_load(&sock->active) ? " active" : "",
+		atomic_load(&sock->closing) ? " closing" : "",
+		atomic_load(&sock->destroying) ? " destroying" : "",
+		atomic_load(&sock->connecting) ? " connecting" : "",
+		sock->accepting ? " accepting" : "");
+	fprintf(stderr, "Created by:\n");
+	backtrace_symbols_fd(sock->backtrace, sock->backtrace_size,
+			     STDERR_FILENO);
+	fprintf(stderr, "\n");
+
+	for (handle = ISC_LIST_HEAD(sock->active_handles); handle != NULL;
+	     handle = ISC_LIST_NEXT(handle, active_link))
+	{
+		static bool first = true;
+		if (first) {
+			fprintf(stderr, "Active handles:\n");
+			first = false;
+		}
+		nmhandle_dump(handle);
+	}
+
+	fprintf(stderr, "\n");
+	UNLOCK(&sock->lock);
+}
+
+void
+isc__nm_dump_active(isc_nm_t *nm) {
+	isc_nmsocket_t *sock = NULL;
+
+	REQUIRE(VALID_NM(nm));
+
+	LOCK(&nm->lock);
+	for (sock = ISC_LIST_HEAD(nm->active_sockets); sock != NULL;
+	     sock = ISC_LIST_NEXT(sock, active_link))
+	{
+		static bool first = true;
+		if (first) {
+			fprintf(stderr, "Outstanding sockets\n");
+			first = false;
+		}
+		nmsocket_dump(sock);
+	}
+	UNLOCK(&nm->lock);
+}
+#endif
diff --git a/lib/isc/netmgr/tcp.c b/lib/isc/netmgr/tcp.c
new file mode 100644
index 0000000..821d6c4
--- /dev/null
+++ b/lib/isc/netmgr/tcp.c
@@ -0,0 +1,1456 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <libgen.h>
+#include <unistd.h>
+#include <uv.h>
+
+#include <isc/atomic.h>
+#include <isc/barrier.h>
+#include <isc/buffer.h>
+#include <isc/condition.h>
+#include <isc/errno.h>
+#include <isc/log.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/netmgr.h>
+#include <isc/quota.h>
+#include <isc/random.h>
+#include <isc/refcount.h>
+#include <isc/region.h>
+#include <isc/result.h>
+#include <isc/sockaddr.h>
+#include <isc/stdtime.h>
+#include <isc/thread.h>
+#include <isc/util.h>
+
+#include "netmgr-int.h"
+#include "uv-compat.h"
+
+static atomic_uint_fast32_t last_tcpquota_log = 0;
+
+static bool
+can_log_tcp_quota(void) {
+	isc_stdtime_t now, last;
+
+	isc_stdtime_get(&now);
+	last = atomic_exchange_relaxed(&last_tcpquota_log, now);
+	if (now != last) {
+		return (true);
+	}
+
+	return (false);
+}
+
+static isc_result_t
+tcp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req);
+
+static void
+tcp_close_direct(isc_nmsocket_t *sock);
+
+static isc_result_t
+tcp_send_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req);
+static void
+tcp_connect_cb(uv_connect_t *uvreq, int status);
+
+static void
+tcp_connection_cb(uv_stream_t *server, int status);
+
+static void
+tcp_close_cb(uv_handle_t *uvhandle);
+
+static isc_result_t
+accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota);
+
+static void
+quota_accept_cb(isc_quota_t *quota, void *sock0);
+
+static void
+failed_accept_cb(isc_nmsocket_t *sock, isc_result_t eresult);
+
+static void
+stop_tcp_parent(isc_nmsocket_t *sock);
+static void
+stop_tcp_child(isc_nmsocket_t *sock);
+
+static void
+failed_accept_cb(isc_nmsocket_t *sock, isc_result_t eresult) {
+	REQUIRE(sock->accepting);
+	REQUIRE(sock->server);
+
+	/*
+	 * Detach the quota early to make room for other connections;
+	 * otherwise it'd be detached later asynchronously, and clog
+	 * the quota unnecessarily.
+	 */
+	if (sock->quota != NULL) {
+		isc_quota_detach(&sock->quota);
+	}
+
+	isc__nmsocket_detach(&sock->server);
+
+	sock->accepting = false;
+
+	switch (eresult) {
+	case ISC_R_NOTCONNECTED:
+		/* IGNORE: The client disconnected before we could accept */
+		break;
+	default:
+		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
+			      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
+			      "Accepting TCP connection failed: %s",
+			      isc_result_totext(eresult));
+	}
+}
+
+static isc_result_t
+tcp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
+	isc__networker_t *worker = NULL;
+	isc_result_t result = ISC_R_UNSET;
+	int r;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(req));
+
+	REQUIRE(isc__nm_in_netthread());
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	worker = &sock->mgr->workers[sock->tid];
+
+	atomic_store(&sock->connecting, true);
+
+	/* 2 minute timeout */
+	result = isc__nm_socket_connectiontimeout(sock->fd, 120 * 1000);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
+	uv_handle_set_data(&sock->uv_handle.handle, sock);
+
+	r = uv_timer_init(&worker->loop, &sock->read_timer);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+
+	r = uv_tcp_open(&sock->uv_handle.tcp, sock->fd);
+	if (r != 0) {
+		isc__nm_closesocket(sock->fd);
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPENFAIL]);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPEN]);
+
+	if (req->local.length != 0) {
+		r = uv_tcp_bind(&sock->uv_handle.tcp, &req->local.type.sa, 0);
+		if (r != 0) {
+			isc__nm_incstats(sock->mgr,
+					 sock->statsindex[STATID_BINDFAIL]);
+			goto done;
+		}
+	}
+
+	uv_handle_set_data(&req->uv_req.handle, req);
+	r = uv_tcp_connect(&req->uv_req.connect, &sock->uv_handle.tcp,
+			   &req->peer.type.sa, tcp_connect_cb);
+	if (r != 0) {
+		isc__nm_incstats(sock->mgr,
+				 sock->statsindex[STATID_CONNECTFAIL]);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CONNECT]);
+
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer,
+			   &req->uv_req.connect);
+	isc__nmsocket_timer_start(sock);
+
+	atomic_store(&sock->connected, true);
+
+done:
+	result = isc__nm_uverr2result(r);
+	LOCK(&sock->lock);
+	sock->result = result;
+	SIGNAL(&sock->cond);
+	if (!atomic_load(&sock->active)) {
+		WAIT(&sock->scond, &sock->lock);
+	}
+	INSIST(atomic_load(&sock->active));
+	UNLOCK(&sock->lock);
+
+	return (result);
+}
+
+void
+isc__nm_async_tcpconnect(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpconnect_t *ievent =
+		(isc__netievent_tcpconnect_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc__nm_uvreq_t *req = ievent->req;
+	isc_result_t result = ISC_R_SUCCESS;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+	REQUIRE(sock->parent == NULL);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	result = tcp_connect_direct(sock, req);
+	if (result != ISC_R_SUCCESS) {
+		atomic_store(&sock->active, false);
+		if (sock->fd != (uv_os_sock_t)(-1)) {
+			isc__nm_tcp_close(sock);
+		}
+		isc__nm_connectcb(sock, req, result, true);
+	}
+
+	/*
+	 * The sock is now attached to the handle.
+	 */
+	isc__nmsocket_detach(&sock);
+}
+
+static void
+tcp_connect_cb(uv_connect_t *uvreq, int status) {
+	isc_result_t result;
+	isc__nm_uvreq_t *req = NULL;
+	isc_nmsocket_t *sock = uv_handle_get_data((uv_handle_t *)uvreq->handle);
+	struct sockaddr_storage ss;
+	int r;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	isc__nmsocket_timer_stop(sock);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+
+	req = uv_handle_get_data((uv_handle_t *)uvreq);
+
+	REQUIRE(VALID_UVREQ(req));
+	REQUIRE(VALID_NMHANDLE(req->handle));
+
+	if (atomic_load(&sock->timedout)) {
+		result = ISC_R_TIMEDOUT;
+		goto error;
+	}
+
+	if (!atomic_load(&sock->connecting)) {
+		/*
+		 * The connect was cancelled from timeout; just clean up
+		 * the req.
+		 */
+		isc__nm_uvreq_put(&req, sock);
+		return;
+	} else if (isc__nmsocket_closing(sock)) {
+		/* Socket was closed midflight by isc__nm_tcp_shutdown() */
+		result = ISC_R_CANCELED;
+		goto error;
+	} else if (status == UV_ETIMEDOUT) {
+		/* Timeout status code here indicates hard error */
+		result = ISC_R_TIMEDOUT;
+		goto error;
+	} else if (status != 0) {
+		result = isc__nm_uverr2result(status);
+		goto error;
+	}
+
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CONNECT]);
+	r = uv_tcp_getpeername(&sock->uv_handle.tcp, (struct sockaddr *)&ss,
+			       &(int){ sizeof(ss) });
+	if (r != 0) {
+		result = isc__nm_uverr2result(r);
+		goto error;
+	}
+
+	atomic_store(&sock->connecting, false);
+
+	result = isc_sockaddr_fromsockaddr(&sock->peer, (struct sockaddr *)&ss);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+	isc__nm_connectcb(sock, req, ISC_R_SUCCESS, false);
+
+	return;
+
+error:
+	isc__nm_failed_connect_cb(sock, req, result, false);
+}
+
+void
+isc_nm_tcpconnect(isc_nm_t *mgr, isc_sockaddr_t *local, isc_sockaddr_t *peer,
+		  isc_nm_cb_t cb, void *cbarg, unsigned int timeout,
+		  size_t extrahandlesize) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc_nmsocket_t *sock = NULL;
+	isc__netievent_tcpconnect_t *ievent = NULL;
+	isc__nm_uvreq_t *req = NULL;
+	sa_family_t sa_family;
+
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(local != NULL);
+	REQUIRE(peer != NULL);
+
+	sa_family = peer->type.sa.sa_family;
+
+	sock = isc_mem_get(mgr->mctx, sizeof(*sock));
+	isc__nmsocket_init(sock, mgr, isc_nm_tcpsocket, local);
+
+	sock->extrahandlesize = extrahandlesize;
+	sock->connect_timeout = timeout;
+	sock->result = ISC_R_UNSET;
+	sock->fd = (uv_os_sock_t)-1;
+	atomic_init(&sock->client, true);
+
+	req = isc__nm_uvreq_get(mgr, sock);
+	req->cb.connect = cb;
+	req->cbarg = cbarg;
+	req->peer = *peer;
+	req->local = *local;
+	req->handle = isc__nmhandle_get(sock, &req->peer, &sock->iface);
+
+	result = isc__nm_socket(sa_family, SOCK_STREAM, 0, &sock->fd);
+	if (result != ISC_R_SUCCESS) {
+		if (isc__nm_in_netthread()) {
+			sock->tid = isc_nm_tid();
+			isc__nmsocket_clearcb(sock);
+			isc__nm_connectcb(sock, req, result, false);
+		} else {
+			isc__nmsocket_clearcb(sock);
+			sock->tid = isc_random_uniform(mgr->nworkers);
+			isc__nm_connectcb(sock, req, result, true);
+		}
+		atomic_store(&sock->closed, true);
+		isc__nmsocket_detach(&sock);
+		return;
+	}
+
+	ievent = isc__nm_get_netievent_tcpconnect(mgr, sock, req);
+
+	if (isc__nm_in_netthread()) {
+		atomic_store(&sock->active, true);
+		sock->tid = isc_nm_tid();
+		isc__nm_async_tcpconnect(&mgr->workers[sock->tid],
+					 (isc__netievent_t *)ievent);
+		isc__nm_put_netievent_tcpconnect(mgr, ievent);
+	} else {
+		atomic_init(&sock->active, false);
+		sock->tid = isc_random_uniform(mgr->nworkers);
+		isc__nm_enqueue_ievent(&mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+	LOCK(&sock->lock);
+	while (sock->result == ISC_R_UNSET) {
+		WAIT(&sock->cond, &sock->lock);
+	}
+	atomic_store(&sock->active, true);
+	BROADCAST(&sock->scond);
+	UNLOCK(&sock->lock);
+}
+
+static uv_os_sock_t
+isc__nm_tcp_lb_socket(isc_nm_t *mgr, sa_family_t sa_family) {
+	isc_result_t result;
+	uv_os_sock_t sock;
+
+	result = isc__nm_socket(sa_family, SOCK_STREAM, 0, &sock);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+	(void)isc__nm_socket_incoming_cpu(sock);
+
+	/* FIXME: set mss */
+
+	result = isc__nm_socket_reuse(sock);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+#ifndef _WIN32
+	if (mgr->load_balance_sockets) {
+		result = isc__nm_socket_reuse_lb(sock);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+	}
+#endif
+
+	return (sock);
+}
+
+static void
+start_tcp_child(isc_nm_t *mgr, isc_sockaddr_t *iface, isc_nmsocket_t *sock,
+		uv_os_sock_t fd, int tid) {
+	isc__netievent_tcplisten_t *ievent = NULL;
+	isc_nmsocket_t *csock = &sock->children[tid];
+
+	isc__nmsocket_init(csock, mgr, isc_nm_tcpsocket, iface);
+	csock->parent = sock;
+	csock->accept_cb = sock->accept_cb;
+	csock->accept_cbarg = sock->accept_cbarg;
+	csock->extrahandlesize = sock->extrahandlesize;
+	csock->backlog = sock->backlog;
+	csock->tid = tid;
+	/*
+	 * We don't attach to quota, just assign - to avoid
+	 * increasing quota unnecessarily.
+	 */
+	csock->pquota = sock->pquota;
+	isc_quota_cb_init(&csock->quotacb, quota_accept_cb, csock);
+
+#ifdef _WIN32
+	UNUSED(fd);
+	csock->fd = isc__nm_tcp_lb_socket(mgr, iface->type.sa.sa_family);
+#else
+	if (mgr->load_balance_sockets) {
+		UNUSED(fd);
+		csock->fd = isc__nm_tcp_lb_socket(mgr,
+						  iface->type.sa.sa_family);
+	} else {
+		csock->fd = dup(fd);
+	}
+#endif
+	REQUIRE(csock->fd >= 0);
+
+	ievent = isc__nm_get_netievent_tcplisten(mgr, csock);
+	isc__nm_maybe_enqueue_ievent(&mgr->workers[tid],
+				     (isc__netievent_t *)ievent);
+}
+
+static void
+enqueue_stoplistening(isc_nmsocket_t *sock) {
+	isc__netievent_tcpstop_t *ievent =
+		isc__nm_get_netievent_tcpstop(sock->mgr, sock);
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+}
+
+isc_result_t
+isc_nm_listentcp(isc_nm_t *mgr, isc_sockaddr_t *iface,
+		 isc_nm_accept_cb_t accept_cb, void *accept_cbarg,
+		 size_t extrahandlesize, int backlog, isc_quota_t *quota,
+		 isc_nmsocket_t **sockp) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc_nmsocket_t *sock = NULL;
+	size_t children_size = 0;
+	uv_os_sock_t fd = -1;
+
+	REQUIRE(VALID_NM(mgr));
+
+	sock = isc_mem_get(mgr->mctx, sizeof(*sock));
+	isc__nmsocket_init(sock, mgr, isc_nm_tcplistener, iface);
+
+	atomic_init(&sock->rchildren, 0);
+#if defined(WIN32)
+	sock->nchildren = 1;
+#else
+	sock->nchildren = mgr->nworkers;
+#endif
+	children_size = sock->nchildren * sizeof(sock->children[0]);
+	sock->children = isc_mem_get(mgr->mctx, children_size);
+	memset(sock->children, 0, children_size);
+
+	sock->result = ISC_R_UNSET;
+
+	sock->accept_cb = accept_cb;
+	sock->accept_cbarg = accept_cbarg;
+	sock->extrahandlesize = extrahandlesize;
+	sock->backlog = backlog;
+	sock->pquota = quota;
+
+	sock->tid = 0;
+	sock->fd = -1;
+
+#ifndef _WIN32
+	if (!mgr->load_balance_sockets) {
+		fd = isc__nm_tcp_lb_socket(mgr, iface->type.sa.sa_family);
+	}
+#endif
+
+	isc_barrier_init(&sock->startlistening, sock->nchildren);
+
+	for (size_t i = 0; i < sock->nchildren; i++) {
+		if ((int)i == isc_nm_tid()) {
+			continue;
+		}
+		start_tcp_child(mgr, iface, sock, fd, i);
+	}
+
+	if (isc__nm_in_netthread()) {
+		start_tcp_child(mgr, iface, sock, fd, isc_nm_tid());
+	}
+
+#ifndef _WIN32
+	if (!mgr->load_balance_sockets) {
+		isc__nm_closesocket(fd);
+	}
+#endif
+
+	LOCK(&sock->lock);
+	while (atomic_load(&sock->rchildren) != sock->nchildren) {
+		WAIT(&sock->cond, &sock->lock);
+	}
+	result = sock->result;
+	atomic_store(&sock->active, true);
+	UNLOCK(&sock->lock);
+
+	INSIST(result != ISC_R_UNSET);
+
+	if (result == ISC_R_SUCCESS) {
+		REQUIRE(atomic_load(&sock->rchildren) == sock->nchildren);
+		*sockp = sock;
+	} else {
+		atomic_store(&sock->active, false);
+		enqueue_stoplistening(sock);
+		isc_nmsocket_close(&sock);
+	}
+
+	return (result);
+}
+
+void
+isc__nm_async_tcplisten(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcplisten_t *ievent = (isc__netievent_tcplisten_t *)ev0;
+	sa_family_t sa_family;
+	int r;
+	int flags = 0;
+	isc_nmsocket_t *sock = NULL;
+	isc_result_t result;
+	isc_nm_t *mgr;
+
+	REQUIRE(VALID_NMSOCK(ievent->sock));
+	REQUIRE(ievent->sock->tid == isc_nm_tid());
+	REQUIRE(VALID_NMSOCK(ievent->sock->parent));
+
+	sock = ievent->sock;
+	sa_family = sock->iface.type.sa.sa_family;
+	mgr = sock->mgr;
+
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+	REQUIRE(sock->parent != NULL);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	/* TODO: set min mss */
+
+	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
+
+	uv_handle_set_data(&sock->uv_handle.handle, sock);
+	/* This keeps the socket alive after everything else is gone */
+	isc__nmsocket_attach(sock, &(isc_nmsocket_t *){ NULL });
+
+	r = uv_timer_init(&worker->loop, &sock->read_timer);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+
+	LOCK(&sock->parent->lock);
+
+	r = uv_tcp_open(&sock->uv_handle.tcp, sock->fd);
+	if (r < 0) {
+		isc__nm_closesocket(sock->fd);
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPENFAIL]);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPEN]);
+
+	if (sa_family == AF_INET6) {
+		flags = UV_TCP_IPV6ONLY;
+	}
+
+#ifdef _WIN32
+	r = isc_uv_tcp_freebind(&sock->uv_handle.tcp, &sock->iface.type.sa,
+				flags);
+	if (r < 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_BINDFAIL]);
+		goto done;
+	}
+#else
+	if (mgr->load_balance_sockets) {
+		r = isc_uv_tcp_freebind(&sock->uv_handle.tcp,
+					&sock->iface.type.sa, flags);
+		if (r < 0) {
+			isc__nm_incstats(sock->mgr,
+					 sock->statsindex[STATID_BINDFAIL]);
+			goto done;
+		}
+	} else {
+		if (sock->parent->fd == -1) {
+			r = isc_uv_tcp_freebind(&sock->uv_handle.tcp,
+						&sock->iface.type.sa, flags);
+			if (r < 0) {
+				isc__nm_incstats(sock->mgr, STATID_BINDFAIL);
+				goto done;
+			}
+			sock->parent->uv_handle.tcp.flags =
+				sock->uv_handle.tcp.flags;
+			sock->parent->fd = sock->fd;
+		} else {
+			/* The socket is already bound, just copy the flags */
+			sock->uv_handle.tcp.flags =
+				sock->parent->uv_handle.tcp.flags;
+		}
+	}
+#endif
+
+	/*
+	 * The callback will run in the same thread uv_listen() was called
+	 * from, so a race with tcp_connection_cb() isn't possible.
+	 */
+	r = uv_listen((uv_stream_t *)&sock->uv_handle.tcp, sock->backlog,
+		      tcp_connection_cb);
+	if (r != 0) {
+		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
+			      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
+			      "uv_listen failed: %s",
+			      isc_result_totext(isc__nm_uverr2result(r)));
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_BINDFAIL]);
+		goto done;
+	}
+
+	atomic_store(&sock->listening, true);
+
+done:
+	result = isc__nm_uverr2result(r);
+	if (result != ISC_R_SUCCESS) {
+		sock->pquota = NULL;
+	}
+
+	atomic_fetch_add(&sock->parent->rchildren, 1);
+	if (sock->parent->result == ISC_R_UNSET) {
+		sock->parent->result = result;
+	}
+	SIGNAL(&sock->parent->cond);
+	UNLOCK(&sock->parent->lock);
+
+	isc_barrier_wait(&sock->parent->startlistening);
+}
+
+static void
+tcp_connection_cb(uv_stream_t *server, int status) {
+	isc_nmsocket_t *ssock = uv_handle_get_data((uv_handle_t *)server);
+	isc_result_t result;
+	isc_quota_t *quota = NULL;
+
+	if (status != 0) {
+		result = isc__nm_uverr2result(status);
+		goto done;
+	}
+
+	REQUIRE(VALID_NMSOCK(ssock));
+	REQUIRE(ssock->tid == isc_nm_tid());
+
+	if (isc__nmsocket_closing(ssock)) {
+		result = ISC_R_CANCELED;
+		goto done;
+	}
+
+	if (ssock->pquota != NULL) {
+		result = isc_quota_attach_cb(ssock->pquota, &quota,
+					     &ssock->quotacb);
+		if (result == ISC_R_QUOTA) {
+			isc__nm_incstats(ssock->mgr,
+					 ssock->statsindex[STATID_ACCEPTFAIL]);
+			goto done;
+		}
+	}
+
+	result = accept_connection(ssock, quota);
+done:
+	isc__nm_accept_connection_log(result, can_log_tcp_quota());
+}
+
+void
+isc__nm_tcp_stoplistening(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_tcplistener);
+
+	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
+					    true))
+	{
+		UNREACHABLE();
+	}
+
+	if (!isc__nm_in_netthread()) {
+		enqueue_stoplistening(sock);
+	} else {
+		stop_tcp_parent(sock);
+	}
+}
+
+void
+isc__nm_async_tcpstop(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpstop_t *ievent = (isc__netievent_tcpstop_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (sock->parent != NULL) {
+		stop_tcp_child(sock);
+		return;
+	}
+
+	stop_tcp_parent(sock);
+}
+
+void
+isc__nm_tcp_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(result != ISC_R_SUCCESS);
+
+	isc__nmsocket_timer_stop(sock);
+	isc__nm_stop_reading(sock);
+
+	if (!sock->recv_read) {
+		goto destroy;
+	}
+	sock->recv_read = false;
+
+	if (sock->recv_cb != NULL) {
+		isc__nm_uvreq_t *req = isc__nm_get_read_req(sock, NULL);
+		isc__nmsocket_clearcb(sock);
+		isc__nm_readcb(sock, req, result);
+	}
+
+destroy:
+	isc__nmsocket_prep_destroy(sock);
+
+	/*
+	 * We need to detach from quota after the read callback function had a
+	 * chance to be executed.
+	 */
+	if (sock->quota != NULL) {
+		isc_quota_detach(&sock->quota);
+	}
+}
+
+void
+isc__nm_tcp_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	isc_nmsocket_t *sock = handle->sock;
+	isc__netievent_tcpstartread_t *ievent = NULL;
+
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+	REQUIRE(sock->statichandle == handle);
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(!sock->recv_read);
+
+	sock->recv_cb = cb;
+	sock->recv_cbarg = cbarg;
+	sock->recv_read = true;
+	if (sock->read_timeout == 0) {
+		sock->read_timeout =
+			(atomic_load(&sock->keepalive)
+				 ? atomic_load(&sock->mgr->keepalive)
+				 : atomic_load(&sock->mgr->idle));
+	}
+
+	ievent = isc__nm_get_netievent_tcpstartread(sock->mgr, sock);
+
+	/*
+	 * 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.
+	 */
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+
+	return;
+}
+
+void
+isc__nm_async_tcpstartread(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpstartread_t *ievent =
+		(isc__netievent_tcpstartread_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc_result_t result;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	UNUSED(worker);
+
+	if (isc__nmsocket_closing(sock)) {
+		result = ISC_R_CANCELED;
+	} else {
+		result = isc__nm_start_reading(sock);
+	}
+
+	if (result != ISC_R_SUCCESS) {
+		sock->reading = true;
+		isc__nm_tcp_failed_read_cb(sock, result);
+		return;
+	}
+
+	isc__nmsocket_timer_start(sock);
+}
+
+void
+isc__nm_tcp_pauseread(isc_nmhandle_t *handle) {
+	isc__netievent_tcppauseread_t *ievent = NULL;
+	isc_nmsocket_t *sock = NULL;
+
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	sock = handle->sock;
+
+	REQUIRE(VALID_NMSOCK(sock));
+
+	if (!atomic_compare_exchange_strong(&sock->readpaused, &(bool){ false },
+					    true))
+	{
+		return;
+	}
+
+	ievent = isc__nm_get_netievent_tcppauseread(sock->mgr, sock);
+
+	isc__nm_maybe_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				     (isc__netievent_t *)ievent);
+
+	return;
+}
+
+void
+isc__nm_async_tcppauseread(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcppauseread_t *ievent =
+		(isc__netievent_tcppauseread_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	UNUSED(worker);
+
+	isc__nmsocket_timer_stop(sock);
+	isc__nm_stop_reading(sock);
+}
+
+void
+isc__nm_tcp_resumeread(isc_nmhandle_t *handle) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	isc__netievent_tcpstartread_t *ievent = NULL;
+	isc_nmsocket_t *sock = handle->sock;
+
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (sock->recv_cb == NULL) {
+		/* We are no longer reading */
+		return;
+	}
+
+	if (!isc__nmsocket_active(sock)) {
+		sock->reading = true;
+		isc__nm_tcp_failed_read_cb(sock, ISC_R_CANCELED);
+		return;
+	}
+
+	if (!atomic_compare_exchange_strong(&sock->readpaused, &(bool){ true },
+					    false))
+	{
+		return;
+	}
+
+	ievent = isc__nm_get_netievent_tcpstartread(sock->mgr, sock);
+
+	isc__nm_maybe_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				     (isc__netievent_t *)ievent);
+}
+
+void
+isc__nm_tcp_read_cb(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf) {
+	isc_nmsocket_t *sock = uv_handle_get_data((uv_handle_t *)stream);
+	isc__nm_uvreq_t *req = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->reading);
+	REQUIRE(buf != NULL);
+
+	if (isc__nmsocket_closing(sock)) {
+		isc__nm_tcp_failed_read_cb(sock, ISC_R_CANCELED);
+		goto free;
+	}
+
+	if (nread < 0) {
+		if (nread != UV_EOF) {
+			isc__nm_incstats(sock->mgr,
+					 sock->statsindex[STATID_RECVFAIL]);
+		}
+
+		isc__nm_tcp_failed_read_cb(sock, isc__nm_uverr2result(nread));
+
+		goto free;
+	}
+
+	req = isc__nm_get_read_req(sock, NULL);
+
+	/*
+	 * The callback will be called synchronously because the
+	 * result is ISC_R_SUCCESS, so we don't need to retain
+	 * the buffer
+	 */
+	req->uvbuf.base = buf->base;
+	req->uvbuf.len = nread;
+
+	if (!atomic_load(&sock->client)) {
+		sock->read_timeout =
+			(atomic_load(&sock->keepalive)
+				 ? atomic_load(&sock->mgr->keepalive)
+				 : atomic_load(&sock->mgr->idle));
+	}
+
+	isc__nm_readcb(sock, req, ISC_R_SUCCESS);
+
+	/* The readcb could have paused the reading */
+	if (sock->reading) {
+		/* The timer will be updated */
+		isc__nmsocket_timer_restart(sock);
+	}
+
+free:
+	if (nread < 0) {
+		/*
+		 * The buffer may be a null buffer on error.
+		 */
+		if (buf->base == NULL && buf->len == 0) {
+			return;
+		}
+	}
+
+	isc__nm_free_uvbuf(sock, buf);
+}
+
+static void
+quota_accept_cb(isc_quota_t *quota, void *sock0) {
+	isc_nmsocket_t *sock = (isc_nmsocket_t *)sock0;
+	isc__netievent_tcpaccept_t *ievent = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+
+	/*
+	 * Create a tcpaccept event and pass it using the async channel.
+	 */
+	ievent = isc__nm_get_netievent_tcpaccept(sock->mgr, sock, quota);
+	isc__nm_maybe_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				     (isc__netievent_t *)ievent);
+}
+
+/*
+ * This is called after we get a quota_accept_cb() callback.
+ */
+void
+isc__nm_async_tcpaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpaccept_t *ievent = (isc__netievent_tcpaccept_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc_result_t result;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	result = accept_connection(sock, ievent->quota);
+	isc__nm_accept_connection_log(result, can_log_tcp_quota());
+}
+
+static isc_result_t
+accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
+	isc_nmsocket_t *csock = NULL;
+	isc__networker_t *worker = NULL;
+	int r;
+	isc_result_t result;
+	struct sockaddr_storage ss;
+	isc_sockaddr_t local;
+	isc_nmhandle_t *handle = NULL;
+
+	REQUIRE(VALID_NMSOCK(ssock));
+	REQUIRE(ssock->tid == isc_nm_tid());
+
+	if (isc__nmsocket_closing(ssock)) {
+		if (quota != NULL) {
+			isc_quota_detach(&quota);
+		}
+		return (ISC_R_CANCELED);
+	}
+
+	csock = isc_mem_get(ssock->mgr->mctx, sizeof(isc_nmsocket_t));
+	isc__nmsocket_init(csock, ssock->mgr, isc_nm_tcpsocket, &ssock->iface);
+	csock->tid = ssock->tid;
+	csock->extrahandlesize = ssock->extrahandlesize;
+	isc__nmsocket_attach(ssock, &csock->server);
+	csock->recv_cb = ssock->recv_cb;
+	csock->recv_cbarg = ssock->recv_cbarg;
+	csock->quota = quota;
+	csock->accepting = true;
+
+	worker = &csock->mgr->workers[isc_nm_tid()];
+
+	r = uv_tcp_init(&worker->loop, &csock->uv_handle.tcp);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
+	uv_handle_set_data(&csock->uv_handle.handle, csock);
+
+	r = uv_timer_init(&worker->loop, &csock->read_timer);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
+	uv_handle_set_data((uv_handle_t *)&csock->read_timer, csock);
+
+	r = uv_accept(&ssock->uv_handle.stream, &csock->uv_handle.stream);
+	if (r != 0) {
+		result = isc__nm_uverr2result(r);
+		goto failure;
+	}
+
+	r = uv_tcp_getpeername(&csock->uv_handle.tcp, (struct sockaddr *)&ss,
+			       &(int){ sizeof(ss) });
+	if (r != 0) {
+		result = isc__nm_uverr2result(r);
+		goto failure;
+	}
+
+	result = isc_sockaddr_fromsockaddr(&csock->peer,
+					   (struct sockaddr *)&ss);
+	if (result != ISC_R_SUCCESS) {
+		goto failure;
+	}
+
+	r = uv_tcp_getsockname(&csock->uv_handle.tcp, (struct sockaddr *)&ss,
+			       &(int){ sizeof(ss) });
+	if (r != 0) {
+		result = isc__nm_uverr2result(r);
+		goto failure;
+	}
+
+	result = isc_sockaddr_fromsockaddr(&local, (struct sockaddr *)&ss);
+	if (result != ISC_R_SUCCESS) {
+		goto failure;
+	}
+
+	handle = isc__nmhandle_get(csock, NULL, &local);
+
+	result = ssock->accept_cb(handle, ISC_R_SUCCESS, ssock->accept_cbarg);
+	if (result != ISC_R_SUCCESS) {
+		isc_nmhandle_detach(&handle);
+		goto failure;
+	}
+
+	csock->accepting = false;
+
+	isc__nm_incstats(csock->mgr, csock->statsindex[STATID_ACCEPT]);
+
+	csock->read_timeout = atomic_load(&csock->mgr->init);
+
+	atomic_fetch_add(&ssock->parent->active_child_connections, 1);
+
+	/*
+	 * The acceptcb needs to attach to the handle if it wants to keep the
+	 * connection alive
+	 */
+	isc_nmhandle_detach(&handle);
+
+	/*
+	 * sock is now attached to the handle.
+	 */
+	isc__nmsocket_detach(&csock);
+
+	return (ISC_R_SUCCESS);
+
+failure:
+	atomic_store(&csock->active, false);
+
+	failed_accept_cb(csock, result);
+
+	isc__nmsocket_prep_destroy(csock);
+
+	isc__nmsocket_detach(&csock);
+
+	return (result);
+}
+
+void
+isc__nm_tcp_send(isc_nmhandle_t *handle, const isc_region_t *region,
+		 isc_nm_cb_t cb, void *cbarg) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	isc_nmsocket_t *sock = handle->sock;
+	isc__netievent_tcpsend_t *ievent = NULL;
+	isc__nm_uvreq_t *uvreq = NULL;
+
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+
+	uvreq = isc__nm_uvreq_get(sock->mgr, sock);
+	uvreq->uvbuf.base = (char *)region->base;
+	uvreq->uvbuf.len = region->length;
+
+	isc_nmhandle_attach(handle, &uvreq->handle);
+
+	uvreq->cb.send = cb;
+	uvreq->cbarg = cbarg;
+
+	ievent = isc__nm_get_netievent_tcpsend(sock->mgr, sock, uvreq);
+	isc__nm_maybe_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				     (isc__netievent_t *)ievent);
+
+	return;
+}
+
+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_NMSOCK(uvreq->sock));
+
+	sock = uvreq->sock;
+
+	isc_nm_timer_stop(uvreq->timer);
+	isc_nm_timer_detach(&uvreq->timer);
+
+	if (status < 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
+		isc__nm_failed_send_cb(sock, uvreq,
+				       isc__nm_uverr2result(status));
+		return;
+	}
+
+	isc__nm_sendcb(sock, uvreq, ISC_R_SUCCESS, false);
+}
+
+/*
+ * Handle 'tcpsend' async event - send a packet on the socket
+ */
+void
+isc__nm_async_tcpsend(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc_result_t result;
+	isc__netievent_tcpsend_t *ievent = (isc__netievent_tcpsend_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc__nm_uvreq_t *uvreq = ievent->req;
+
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+	REQUIRE(sock->tid == isc_nm_tid());
+	UNUSED(worker);
+
+	if (sock->write_timeout == 0) {
+		sock->write_timeout =
+			(atomic_load(&sock->keepalive)
+				 ? atomic_load(&sock->mgr->keepalive)
+				 : atomic_load(&sock->mgr->idle));
+	}
+
+	result = tcp_send_direct(sock, uvreq);
+	if (result != ISC_R_SUCCESS) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
+		isc__nm_failed_send_cb(sock, uvreq, result);
+	}
+}
+
+static isc_result_t
+tcp_send_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(req));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+
+	int r;
+
+	if (isc__nmsocket_closing(sock)) {
+		return (ISC_R_CANCELED);
+	}
+
+	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);
+}
+
+static void
+tcp_stop_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+	uv_handle_set_data(handle, NULL);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->closing));
+
+	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
+					    true))
+	{
+		UNREACHABLE();
+	}
+
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CLOSE]);
+
+	atomic_store(&sock->listening, false);
+
+	isc__nmsocket_detach(&sock);
+}
+
+static void
+tcp_close_sock(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->closing));
+
+	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
+					    true))
+	{
+		UNREACHABLE();
+	}
+
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CLOSE]);
+
+	if (sock->server != NULL) {
+		isc__nmsocket_detach(&sock->server);
+	}
+
+	atomic_store(&sock->connected, false);
+
+	isc__nmsocket_prep_destroy(sock);
+}
+
+static void
+tcp_close_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+	uv_handle_set_data(handle, NULL);
+
+	tcp_close_sock(sock);
+}
+
+static void
+read_timer_close_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+	uv_handle_set_data(handle, NULL);
+
+	if (sock->parent) {
+		uv_close(&sock->uv_handle.handle, tcp_stop_cb);
+	} else if (uv_is_closing(&sock->uv_handle.handle)) {
+		tcp_close_sock(sock);
+	} else {
+		uv_close(&sock->uv_handle.handle, tcp_close_cb);
+	}
+}
+
+static void
+stop_tcp_child(isc_nmsocket_t *sock) {
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
+					    true))
+	{
+		return;
+	}
+
+	tcp_close_direct(sock);
+
+	atomic_fetch_sub(&sock->parent->rchildren, 1);
+
+	isc_barrier_wait(&sock->parent->stoplistening);
+}
+
+static void
+stop_tcp_parent(isc_nmsocket_t *sock) {
+	isc_nmsocket_t *csock = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->type == isc_nm_tcplistener);
+
+	isc_barrier_init(&sock->stoplistening, sock->nchildren);
+
+	for (size_t i = 0; i < sock->nchildren; i++) {
+		csock = &sock->children[i];
+		REQUIRE(VALID_NMSOCK(csock));
+
+		if ((int)i == isc_nm_tid()) {
+			/*
+			 * We need to schedule closing the other sockets first
+			 */
+			continue;
+		}
+
+		atomic_store(&csock->active, false);
+		enqueue_stoplistening(csock);
+	}
+
+	csock = &sock->children[isc_nm_tid()];
+	atomic_store(&csock->active, false);
+	stop_tcp_child(csock);
+
+	atomic_store(&sock->closed, true);
+	isc__nmsocket_prep_destroy(sock);
+}
+
+static void
+tcp_close_direct(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->closing));
+
+	if (sock->server != NULL) {
+		REQUIRE(VALID_NMSOCK(sock->server));
+		REQUIRE(VALID_NMSOCK(sock->server->parent));
+		if (sock->server->parent != NULL) {
+			atomic_fetch_sub(
+				&sock->server->parent->active_child_connections,
+				1);
+		}
+	}
+
+	if (sock->quota != NULL) {
+		isc_quota_detach(&sock->quota);
+	}
+
+	isc__nmsocket_timer_stop(sock);
+	isc__nm_stop_reading(sock);
+
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
+}
+
+void
+isc__nm_tcp_close(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+	REQUIRE(!isc__nmsocket_active(sock));
+
+	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
+					    true))
+	{
+		return;
+	}
+
+	if (sock->tid == isc_nm_tid()) {
+		tcp_close_direct(sock);
+	} else {
+		/*
+		 * We need to create an event and pass it using async channel
+		 */
+		isc__netievent_tcpclose_t *ievent =
+			isc__nm_get_netievent_tcpclose(sock->mgr, sock);
+
+		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+}
+
+void
+isc__nm_async_tcpclose(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpclose_t *ievent = (isc__netievent_tcpclose_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	UNUSED(worker);
+
+	tcp_close_direct(sock);
+}
+
+static void
+tcp_close_connect_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+
+	REQUIRE(VALID_NMSOCK(sock));
+
+	REQUIRE(isc__nm_in_netthread());
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	isc__nmsocket_prep_destroy(sock);
+	isc__nmsocket_detach(&sock);
+}
+
+void
+isc__nm_tcp_shutdown(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+
+	/*
+	 * If the socket is active, mark it inactive and
+	 * continue. If it isn't active, stop now.
+	 */
+	if (!isc__nmsocket_deactivate(sock)) {
+		return;
+	}
+
+	if (sock->accepting) {
+		return;
+	}
+
+	if (atomic_load(&sock->connecting)) {
+		isc_nmsocket_t *tsock = NULL;
+		isc__nmsocket_attach(sock, &tsock);
+		uv_close(&sock->uv_handle.handle, tcp_close_connect_cb);
+		return;
+	}
+
+	if (sock->statichandle != NULL) {
+		isc__nm_tcp_failed_read_cb(sock, ISC_R_CANCELED);
+		return;
+	}
+
+	/*
+	 * Otherwise, we just send the socket to abyss...
+	 */
+	if (sock->parent == NULL) {
+		isc__nmsocket_prep_destroy(sock);
+	}
+}
+
+void
+isc__nm_tcp_cancelread(isc_nmhandle_t *handle) {
+	isc_nmsocket_t *sock = NULL;
+	isc__netievent_tcpcancel_t *ievent = NULL;
+
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	sock = handle->sock;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_tcpsocket);
+
+	ievent = isc__nm_get_netievent_tcpcancel(sock->mgr, sock, handle);
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+}
+
+void
+isc__nm_async_tcpcancel(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpcancel_t *ievent = (isc__netievent_tcpcancel_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	UNUSED(worker);
+
+	uv_timer_stop(&sock->read_timer);
+
+	isc__nm_tcp_failed_read_cb(sock, ISC_R_EOF);
+}
+
+int_fast32_t
+isc__nm_tcp_listener_nactive(isc_nmsocket_t *listener) {
+	int_fast32_t nactive;
+
+	REQUIRE(VALID_NMSOCK(listener));
+
+	nactive = atomic_load(&listener->active_child_connections);
+	INSIST(nactive >= 0);
+	return (nactive);
+}
diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
new file mode 100644
index 0000000..bd593eb
--- /dev/null
+++ b/lib/isc/netmgr/tcpdns.c
@@ -0,0 +1,1505 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <libgen.h>
+#include <unistd.h>
+#include <uv.h>
+
+#include <isc/atomic.h>
+#include <isc/barrier.h>
+#include <isc/buffer.h>
+#include <isc/condition.h>
+#include <isc/errno.h>
+#include <isc/log.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/netmgr.h>
+#include <isc/quota.h>
+#include <isc/random.h>
+#include <isc/refcount.h>
+#include <isc/region.h>
+#include <isc/result.h>
+#include <isc/sockaddr.h>
+#include <isc/stdtime.h>
+#include <isc/thread.h>
+#include <isc/util.h>
+
+#include "netmgr-int.h"
+#include "uv-compat.h"
+
+static atomic_uint_fast32_t last_tcpdnsquota_log = 0;
+
+static bool
+can_log_tcpdns_quota(void) {
+	isc_stdtime_t now, last;
+
+	isc_stdtime_get(&now);
+	last = atomic_exchange_relaxed(&last_tcpdnsquota_log, now);
+	if (now != last) {
+		return (true);
+	}
+
+	return (false);
+}
+
+static isc_result_t
+tcpdns_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req);
+
+static void
+tcpdns_close_direct(isc_nmsocket_t *sock);
+
+static void
+tcpdns_connect_cb(uv_connect_t *uvreq, int status);
+
+static void
+tcpdns_connection_cb(uv_stream_t *server, int status);
+
+static void
+tcpdns_close_cb(uv_handle_t *uvhandle);
+
+static isc_result_t
+accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota);
+
+static void
+quota_accept_cb(isc_quota_t *quota, void *sock0);
+
+static void
+stop_tcpdns_parent(isc_nmsocket_t *sock);
+static void
+stop_tcpdns_child(isc_nmsocket_t *sock);
+
+static isc_result_t
+tcpdns_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
+	isc__networker_t *worker = NULL;
+	isc_result_t result = ISC_R_UNSET;
+	int r;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(req));
+
+	REQUIRE(isc__nm_in_netthread());
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	worker = &sock->mgr->workers[sock->tid];
+
+	atomic_store(&sock->connecting, true);
+
+	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
+	uv_handle_set_data(&sock->uv_handle.handle, sock);
+
+	r = uv_timer_init(&worker->loop, &sock->read_timer);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+
+	if (isc__nm_closing(sock)) {
+		result = ISC_R_CANCELED;
+		goto error;
+	}
+
+	r = uv_tcp_open(&sock->uv_handle.tcp, sock->fd);
+	if (r != 0) {
+		isc__nm_closesocket(sock->fd);
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPENFAIL]);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPEN]);
+
+	if (req->local.length != 0) {
+		r = uv_tcp_bind(&sock->uv_handle.tcp, &req->local.type.sa, 0);
+		/*
+		 * In case of shared socket UV_EINVAL will be returned and needs
+		 * to be ignored
+		 */
+		if (r != 0 && r != UV_EINVAL) {
+			isc__nm_incstats(sock->mgr,
+					 sock->statsindex[STATID_BINDFAIL]);
+			goto done;
+		}
+	}
+
+	uv_handle_set_data(&req->uv_req.handle, req);
+	r = uv_tcp_connect(&req->uv_req.connect, &sock->uv_handle.tcp,
+			   &req->peer.type.sa, tcpdns_connect_cb);
+	if (r != 0) {
+		isc__nm_incstats(sock->mgr,
+				 sock->statsindex[STATID_CONNECTFAIL]);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CONNECT]);
+
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer,
+			   &req->uv_req.connect);
+	isc__nmsocket_timer_start(sock);
+
+	atomic_store(&sock->connected, true);
+
+done:
+	result = isc__nm_uverr2result(r);
+error:
+	LOCK(&sock->lock);
+	sock->result = result;
+	SIGNAL(&sock->cond);
+	if (!atomic_load(&sock->active)) {
+		WAIT(&sock->scond, &sock->lock);
+	}
+	INSIST(atomic_load(&sock->active));
+	UNLOCK(&sock->lock);
+
+	return (result);
+}
+
+void
+isc__nm_async_tcpdnsconnect(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpdnsconnect_t *ievent =
+		(isc__netievent_tcpdnsconnect_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc__nm_uvreq_t *req = ievent->req;
+	isc_result_t result = ISC_R_SUCCESS;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_tcpdnssocket);
+	REQUIRE(sock->parent == NULL);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	result = tcpdns_connect_direct(sock, req);
+	if (result != ISC_R_SUCCESS) {
+		isc__nmsocket_clearcb(sock);
+		isc__nm_connectcb(sock, req, result, true);
+		atomic_store(&sock->active, false);
+		isc__nm_tcpdns_close(sock);
+	}
+
+	/*
+	 * The sock is now attached to the handle.
+	 */
+	isc__nmsocket_detach(&sock);
+}
+
+static void
+tcpdns_connect_cb(uv_connect_t *uvreq, int status) {
+	isc_result_t result;
+	isc__nm_uvreq_t *req = NULL;
+	isc_nmsocket_t *sock = uv_handle_get_data((uv_handle_t *)uvreq->handle);
+	struct sockaddr_storage ss;
+	int r;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	isc__nmsocket_timer_stop(sock);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+
+	req = uv_handle_get_data((uv_handle_t *)uvreq);
+
+	REQUIRE(VALID_UVREQ(req));
+	REQUIRE(VALID_NMHANDLE(req->handle));
+
+	if (atomic_load(&sock->timedout)) {
+		result = ISC_R_TIMEDOUT;
+		goto error;
+	}
+
+	if (isc__nmsocket_closing(sock)) {
+		/* Socket was closed midflight by isc__nm_tcpdns_shutdown() */
+		result = ISC_R_CANCELED;
+		goto error;
+	} else if (status == UV_ETIMEDOUT) {
+		/* Timeout status code here indicates hard error */
+		result = ISC_R_TIMEDOUT;
+		goto error;
+	} else if (status != 0) {
+		result = isc__nm_uverr2result(status);
+		goto error;
+	}
+
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CONNECT]);
+	r = uv_tcp_getpeername(&sock->uv_handle.tcp, (struct sockaddr *)&ss,
+			       &(int){ sizeof(ss) });
+	if (r != 0) {
+		result = isc__nm_uverr2result(r);
+		goto error;
+	}
+
+	atomic_store(&sock->connecting, false);
+
+	result = isc_sockaddr_fromsockaddr(&sock->peer, (struct sockaddr *)&ss);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+	isc__nm_connectcb(sock, req, ISC_R_SUCCESS, false);
+
+	return;
+
+error:
+	isc__nm_failed_connect_cb(sock, req, result, false);
+}
+
+void
+isc_nm_tcpdnsconnect(isc_nm_t *mgr, isc_sockaddr_t *local, isc_sockaddr_t *peer,
+		     isc_nm_cb_t cb, void *cbarg, unsigned int timeout,
+		     size_t extrahandlesize) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc_nmsocket_t *sock = NULL;
+	isc__netievent_tcpdnsconnect_t *ievent = NULL;
+	isc__nm_uvreq_t *req = NULL;
+	sa_family_t sa_family;
+
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(local != NULL);
+	REQUIRE(peer != NULL);
+
+	sa_family = peer->type.sa.sa_family;
+
+	sock = isc_mem_get(mgr->mctx, sizeof(*sock));
+	isc__nmsocket_init(sock, mgr, isc_nm_tcpdnssocket, local);
+
+	sock->extrahandlesize = extrahandlesize;
+	sock->connect_timeout = timeout;
+	sock->result = ISC_R_UNSET;
+	atomic_init(&sock->client, true);
+
+	req = isc__nm_uvreq_get(mgr, sock);
+	req->cb.connect = cb;
+	req->cbarg = cbarg;
+	req->peer = *peer;
+	req->local = *local;
+	req->handle = isc__nmhandle_get(sock, &req->peer, &sock->iface);
+
+	result = isc__nm_socket(sa_family, SOCK_STREAM, 0, &sock->fd);
+	if (result != ISC_R_SUCCESS) {
+		if (isc__nm_in_netthread()) {
+			sock->tid = isc_nm_tid();
+		}
+		isc__nmsocket_clearcb(sock);
+		isc__nm_connectcb(sock, req, result, true);
+		atomic_store(&sock->closed, true);
+		isc__nmsocket_detach(&sock);
+		return;
+	}
+
+	/* 2 minute timeout */
+	result = isc__nm_socket_connectiontimeout(sock->fd, 120 * 1000);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+	ievent = isc__nm_get_netievent_tcpdnsconnect(mgr, sock, req);
+
+	if (isc__nm_in_netthread()) {
+		atomic_store(&sock->active, true);
+		sock->tid = isc_nm_tid();
+		isc__nm_async_tcpdnsconnect(&mgr->workers[sock->tid],
+					    (isc__netievent_t *)ievent);
+		isc__nm_put_netievent_tcpdnsconnect(mgr, ievent);
+	} else {
+		atomic_init(&sock->active, false);
+		sock->tid = isc_random_uniform(mgr->nworkers);
+		isc__nm_enqueue_ievent(&mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+
+	LOCK(&sock->lock);
+	while (sock->result == ISC_R_UNSET) {
+		WAIT(&sock->cond, &sock->lock);
+	}
+	atomic_store(&sock->active, true);
+	BROADCAST(&sock->scond);
+	UNLOCK(&sock->lock);
+}
+
+static uv_os_sock_t
+isc__nm_tcpdns_lb_socket(isc_nm_t *mgr, sa_family_t sa_family) {
+	isc_result_t result;
+	uv_os_sock_t sock;
+
+	result = isc__nm_socket(sa_family, SOCK_STREAM, 0, &sock);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+	(void)isc__nm_socket_incoming_cpu(sock);
+
+	/* FIXME: set mss */
+
+	result = isc__nm_socket_reuse(sock);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+#ifndef _WIN32
+	if (mgr->load_balance_sockets) {
+		result = isc__nm_socket_reuse_lb(sock);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+	}
+#endif
+
+	return (sock);
+}
+
+static void
+enqueue_stoplistening(isc_nmsocket_t *sock) {
+	isc__netievent_tcpdnsstop_t *ievent =
+		isc__nm_get_netievent_tcpdnsstop(sock->mgr, sock);
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+}
+
+static void
+start_tcpdns_child(isc_nm_t *mgr, isc_sockaddr_t *iface, isc_nmsocket_t *sock,
+		   uv_os_sock_t fd, int tid) {
+	isc__netievent_tcpdnslisten_t *ievent = NULL;
+	isc_nmsocket_t *csock = &sock->children[tid];
+
+	isc__nmsocket_init(csock, mgr, isc_nm_tcpdnssocket, iface);
+	csock->parent = sock;
+	csock->accept_cb = sock->accept_cb;
+	csock->accept_cbarg = sock->accept_cbarg;
+	csock->recv_cb = sock->recv_cb;
+	csock->recv_cbarg = sock->recv_cbarg;
+	csock->extrahandlesize = sock->extrahandlesize;
+	csock->backlog = sock->backlog;
+	csock->tid = tid;
+	/*
+	 * We don't attach to quota, just assign - to avoid
+	 * increasing quota unnecessarily.
+	 */
+	csock->pquota = sock->pquota;
+	isc_quota_cb_init(&csock->quotacb, quota_accept_cb, csock);
+
+#ifdef _WIN32
+	UNUSED(fd);
+	csock->fd = isc__nm_tcpdns_lb_socket(mgr, iface->type.sa.sa_family);
+#else
+	if (mgr->load_balance_sockets) {
+		UNUSED(fd);
+		csock->fd = isc__nm_tcpdns_lb_socket(mgr,
+						     iface->type.sa.sa_family);
+	} else {
+		csock->fd = dup(fd);
+	}
+#endif
+	REQUIRE(csock->fd >= 0);
+
+	ievent = isc__nm_get_netievent_tcpdnslisten(mgr, csock);
+	isc__nm_maybe_enqueue_ievent(&mgr->workers[tid],
+				     (isc__netievent_t *)ievent);
+}
+isc_result_t
+isc_nm_listentcpdns(isc_nm_t *mgr, isc_sockaddr_t *iface,
+		    isc_nm_recv_cb_t recv_cb, void *recv_cbarg,
+		    isc_nm_accept_cb_t accept_cb, void *accept_cbarg,
+		    size_t extrahandlesize, int backlog, isc_quota_t *quota,
+		    isc_nmsocket_t **sockp) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc_nmsocket_t *sock = NULL;
+	size_t children_size = 0;
+	uv_os_sock_t fd = -1;
+
+	REQUIRE(VALID_NM(mgr));
+
+	sock = isc_mem_get(mgr->mctx, sizeof(*sock));
+	isc__nmsocket_init(sock, mgr, isc_nm_tcpdnslistener, iface);
+
+	atomic_init(&sock->rchildren, 0);
+#if defined(WIN32)
+	sock->nchildren = 1;
+#else
+	sock->nchildren = mgr->nworkers;
+#endif
+	children_size = sock->nchildren * sizeof(sock->children[0]);
+	sock->children = isc_mem_get(mgr->mctx, children_size);
+	memset(sock->children, 0, children_size);
+
+	sock->result = ISC_R_UNSET;
+	sock->accept_cb = accept_cb;
+	sock->accept_cbarg = accept_cbarg;
+	sock->recv_cb = recv_cb;
+	sock->recv_cbarg = recv_cbarg;
+	sock->extrahandlesize = extrahandlesize;
+	sock->backlog = backlog;
+	sock->pquota = quota;
+
+	sock->tid = 0;
+	sock->fd = -1;
+
+#ifndef _WIN32
+	if (!mgr->load_balance_sockets) {
+		fd = isc__nm_tcpdns_lb_socket(mgr, iface->type.sa.sa_family);
+	}
+#endif
+
+	isc_barrier_init(&sock->startlistening, sock->nchildren);
+
+	for (size_t i = 0; i < sock->nchildren; i++) {
+		if ((int)i == isc_nm_tid()) {
+			continue;
+		}
+		start_tcpdns_child(mgr, iface, sock, fd, i);
+	}
+
+	if (isc__nm_in_netthread()) {
+		start_tcpdns_child(mgr, iface, sock, fd, isc_nm_tid());
+	}
+
+#ifndef _WIN32
+	if (!mgr->load_balance_sockets) {
+		isc__nm_closesocket(fd);
+	}
+#endif
+
+	LOCK(&sock->lock);
+	while (atomic_load(&sock->rchildren) != sock->nchildren) {
+		WAIT(&sock->cond, &sock->lock);
+	}
+	result = sock->result;
+	atomic_store(&sock->active, true);
+	UNLOCK(&sock->lock);
+
+	INSIST(result != ISC_R_UNSET);
+
+	if (result == ISC_R_SUCCESS) {
+		REQUIRE(atomic_load(&sock->rchildren) == sock->nchildren);
+		*sockp = sock;
+	} else {
+		atomic_store(&sock->active, false);
+		enqueue_stoplistening(sock);
+		isc_nmsocket_close(&sock);
+	}
+
+	return (result);
+}
+
+void
+isc__nm_async_tcpdnslisten(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpdnslisten_t *ievent =
+		(isc__netievent_tcpdnslisten_t *)ev0;
+	sa_family_t sa_family;
+	int r;
+	int flags = 0;
+	isc_nmsocket_t *sock = NULL;
+	isc_result_t result = ISC_R_UNSET;
+	isc_nm_t *mgr = NULL;
+
+	REQUIRE(VALID_NMSOCK(ievent->sock));
+	REQUIRE(ievent->sock->tid == isc_nm_tid());
+	REQUIRE(VALID_NMSOCK(ievent->sock->parent));
+
+	sock = ievent->sock;
+	sa_family = sock->iface.type.sa.sa_family;
+	mgr = sock->mgr;
+
+	REQUIRE(sock->type == isc_nm_tcpdnssocket);
+	REQUIRE(sock->parent != NULL);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	/* TODO: set min mss */
+
+	r = uv_tcp_init(&worker->loop, &sock->uv_handle.tcp);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
+	uv_handle_set_data(&sock->uv_handle.handle, sock);
+	/* This keeps the socket alive after everything else is gone */
+	isc__nmsocket_attach(sock, &(isc_nmsocket_t *){ NULL });
+
+	r = uv_timer_init(&worker->loop, &sock->read_timer);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+
+	LOCK(&sock->parent->lock);
+
+	r = uv_tcp_open(&sock->uv_handle.tcp, sock->fd);
+	if (r < 0) {
+		isc__nm_closesocket(sock->fd);
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPENFAIL]);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPEN]);
+
+	if (sa_family == AF_INET6) {
+		flags = UV_TCP_IPV6ONLY;
+	}
+
+#ifdef _WIN32
+	r = isc_uv_tcp_freebind(&sock->uv_handle.tcp, &sock->iface.type.sa,
+				flags);
+	if (r < 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_BINDFAIL]);
+		goto done;
+	}
+#else
+	if (mgr->load_balance_sockets) {
+		r = isc_uv_tcp_freebind(&sock->uv_handle.tcp,
+					&sock->iface.type.sa, flags);
+		if (r < 0) {
+			isc__nm_incstats(sock->mgr,
+					 sock->statsindex[STATID_BINDFAIL]);
+			goto done;
+		}
+	} else {
+		if (sock->parent->fd == -1) {
+			r = isc_uv_tcp_freebind(&sock->uv_handle.tcp,
+						&sock->iface.type.sa, flags);
+			if (r < 0) {
+				isc__nm_incstats(sock->mgr, STATID_BINDFAIL);
+				goto done;
+			}
+			sock->parent->uv_handle.tcp.flags =
+				sock->uv_handle.tcp.flags;
+			sock->parent->fd = sock->fd;
+		} else {
+			/* The socket is already bound, just copy the flags */
+			sock->uv_handle.tcp.flags =
+				sock->parent->uv_handle.tcp.flags;
+		}
+	}
+#endif
+
+	/*
+	 * The callback will run in the same thread uv_listen() was called
+	 * from, so a race with tcpdns_connection_cb() isn't possible.
+	 */
+	r = uv_listen((uv_stream_t *)&sock->uv_handle.tcp, sock->backlog,
+		      tcpdns_connection_cb);
+	if (r != 0) {
+		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
+			      ISC_LOGMODULE_NETMGR, ISC_LOG_ERROR,
+			      "uv_listen failed: %s",
+			      isc_result_totext(isc__nm_uverr2result(r)));
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_BINDFAIL]);
+		goto done;
+	}
+
+	atomic_store(&sock->listening, true);
+
+done:
+	result = isc__nm_uverr2result(r);
+	if (result != ISC_R_SUCCESS) {
+		sock->pquota = NULL;
+	}
+
+	atomic_fetch_add(&sock->parent->rchildren, 1);
+	if (sock->parent->result == ISC_R_UNSET) {
+		sock->parent->result = result;
+	}
+	SIGNAL(&sock->parent->cond);
+	UNLOCK(&sock->parent->lock);
+
+	isc_barrier_wait(&sock->parent->startlistening);
+}
+
+static void
+tcpdns_connection_cb(uv_stream_t *server, int status) {
+	isc_nmsocket_t *ssock = uv_handle_get_data((uv_handle_t *)server);
+	isc_result_t result;
+	isc_quota_t *quota = NULL;
+
+	if (status != 0) {
+		result = isc__nm_uverr2result(status);
+		goto done;
+	}
+
+	REQUIRE(VALID_NMSOCK(ssock));
+	REQUIRE(ssock->tid == isc_nm_tid());
+
+	if (isc__nmsocket_closing(ssock)) {
+		result = ISC_R_CANCELED;
+		goto done;
+	}
+
+	if (ssock->pquota != NULL) {
+		result = isc_quota_attach_cb(ssock->pquota, &quota,
+					     &ssock->quotacb);
+		if (result == ISC_R_QUOTA) {
+			isc__nm_incstats(ssock->mgr,
+					 ssock->statsindex[STATID_ACCEPTFAIL]);
+			goto done;
+		}
+	}
+
+	result = accept_connection(ssock, quota);
+done:
+	isc__nm_accept_connection_log(result, can_log_tcpdns_quota());
+}
+
+void
+isc__nm_tcpdns_stoplistening(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_tcpdnslistener);
+
+	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
+					    true))
+	{
+		UNREACHABLE();
+	}
+
+	if (!isc__nm_in_netthread()) {
+		enqueue_stoplistening(sock);
+	} else {
+		stop_tcpdns_parent(sock);
+	}
+}
+
+void
+isc__nm_async_tcpdnsstop(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpdnsstop_t *ievent =
+		(isc__netievent_tcpdnsstop_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (sock->parent != NULL) {
+		stop_tcpdns_child(sock);
+		return;
+	}
+
+	stop_tcpdns_parent(sock);
+}
+
+void
+isc__nm_tcpdns_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(result != ISC_R_SUCCESS);
+
+	isc__nmsocket_timer_stop(sock);
+	isc__nm_stop_reading(sock);
+
+	if (!sock->recv_read) {
+		goto destroy;
+	}
+	sock->recv_read = false;
+
+	if (sock->recv_cb != NULL) {
+		isc__nm_uvreq_t *req = isc__nm_get_read_req(sock, NULL);
+		isc__nmsocket_clearcb(sock);
+		isc__nm_readcb(sock, req, result);
+	}
+
+destroy:
+	isc__nmsocket_prep_destroy(sock);
+
+	/*
+	 * We need to detach from quota after the read callback function had a
+	 * chance to be executed.
+	 */
+	if (sock->quota != NULL) {
+		isc_quota_detach(&sock->quota);
+	}
+}
+
+void
+isc__nm_tcpdns_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	isc_nmsocket_t *sock = handle->sock;
+	isc__netievent_tcpdnsread_t *ievent = NULL;
+
+	REQUIRE(sock->type == isc_nm_tcpdnssocket);
+	REQUIRE(sock->statichandle == handle);
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(!sock->recv_read);
+
+	sock->recv_cb = cb;
+	sock->recv_cbarg = cbarg;
+	sock->recv_read = true;
+	if (sock->read_timeout == 0) {
+		sock->read_timeout =
+			(atomic_load(&sock->keepalive)
+				 ? atomic_load(&sock->mgr->keepalive)
+				 : atomic_load(&sock->mgr->idle));
+	}
+
+	ievent = isc__nm_get_netievent_tcpdnsread(sock->mgr, sock);
+
+	/*
+	 * 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.
+	 */
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+
+	return;
+}
+
+void
+isc__nm_async_tcpdnsread(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpdnsread_t *ievent =
+		(isc__netievent_tcpdnsread_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc_result_t result;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (isc__nmsocket_closing(sock)) {
+		result = ISC_R_CANCELED;
+	} else {
+		result = isc__nm_process_sock_buffer(sock);
+	}
+
+	if (result != ISC_R_SUCCESS) {
+		sock->reading = true;
+		isc__nm_failed_read_cb(sock, result, false);
+	}
+}
+
+/*
+ * Process a single packet from the incoming buffer.
+ *
+ * Return ISC_R_SUCCESS and attach 'handlep' to a handle if something
+ * was processed; return ISC_R_NOMORE if there isn't a full message
+ * to be processed.
+ *
+ * The caller will need to unreference the handle.
+ */
+isc_result_t
+isc__nm_tcpdns_processbuffer(isc_nmsocket_t *sock) {
+	size_t len;
+	isc__nm_uvreq_t *req = NULL;
+	isc_nmhandle_t *handle = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (isc__nmsocket_closing(sock)) {
+		return (ISC_R_CANCELED);
+	}
+
+	/*
+	 * If we don't even have the length yet, we can't do
+	 * anything.
+	 */
+	if (sock->buf_len < 2) {
+		return (ISC_R_NOMORE);
+	}
+
+	/*
+	 * Process the first packet from the buffer, leaving
+	 * the rest (if any) for later.
+	 */
+	len = ntohs(*(uint16_t *)sock->buf);
+	if (len > sock->buf_len - 2) {
+		return (ISC_R_NOMORE);
+	}
+
+	req = isc__nm_get_read_req(sock, NULL);
+	REQUIRE(VALID_UVREQ(req));
+
+	/*
+	 * We need to launch the resume_processing after the buffer has
+	 * been consumed, thus we need to delay the detaching the handle.
+	 */
+	isc_nmhandle_attach(req->handle, &handle);
+
+	/*
+	 * The callback will be called synchronously because the
+	 * result is ISC_R_SUCCESS, so we don't need to have
+	 * the buffer on the heap
+	 */
+	req->uvbuf.base = (char *)sock->buf + 2;
+	req->uvbuf.len = len;
+
+	/*
+	 * If isc__nm_tcpdns_read() was called, it will be satisfied by single
+	 * DNS message in the next call.
+	 */
+	sock->recv_read = false;
+
+	/*
+	 * The assertion failure here means that there's a errnoneous extra
+	 * nmhandle detach happening in the callback and resume_processing gets
+	 * called while we are still processing the buffer.
+	 */
+	REQUIRE(sock->processing == false);
+	sock->processing = true;
+	isc__nm_readcb(sock, req, ISC_R_SUCCESS);
+	sock->processing = false;
+
+	len += 2;
+	sock->buf_len -= len;
+	if (sock->buf_len > 0) {
+		memmove(sock->buf, sock->buf + len, sock->buf_len);
+	}
+
+	isc_nmhandle_detach(&handle);
+
+	return (ISC_R_SUCCESS);
+}
+
+void
+isc__nm_tcpdns_read_cb(uv_stream_t *stream, ssize_t nread,
+		       const uv_buf_t *buf) {
+	isc_nmsocket_t *sock = uv_handle_get_data((uv_handle_t *)stream);
+	uint8_t *base = NULL;
+	size_t len;
+	isc_result_t result;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->reading);
+	REQUIRE(buf != NULL);
+
+	if (isc__nmsocket_closing(sock)) {
+		isc__nm_failed_read_cb(sock, ISC_R_CANCELED, true);
+		goto free;
+	}
+
+	if (nread < 0) {
+		if (nread != UV_EOF) {
+			isc__nm_incstats(sock->mgr,
+					 sock->statsindex[STATID_RECVFAIL]);
+		}
+
+		isc__nm_failed_read_cb(sock, isc__nm_uverr2result(nread), true);
+		goto free;
+	}
+
+	base = (uint8_t *)buf->base;
+	len = nread;
+
+	/*
+	 * FIXME: We can avoid the memmove here if we know we have received full
+	 * packet; e.g. we should be smarter, a.s. there are just few situations
+	 *
+	 * The tcp_alloc_buf should be smarter and point the uv_read_start to
+	 * the position where previous read has ended in the sock->buf, that way
+	 * the data could be read directly into sock->buf.
+	 */
+
+	if (sock->buf_len + len > sock->buf_size) {
+		isc__nm_alloc_dnsbuf(sock, sock->buf_len + len);
+	}
+	memmove(sock->buf + sock->buf_len, base, len);
+	sock->buf_len += len;
+
+	if (!atomic_load(&sock->client)) {
+		sock->read_timeout = atomic_load(&sock->mgr->idle);
+	}
+
+	result = isc__nm_process_sock_buffer(sock);
+	if (result != ISC_R_SUCCESS) {
+		isc__nm_failed_read_cb(sock, result, true);
+	}
+free:
+	if (nread < 0) {
+		/*
+		 * The buffer may be a null buffer on error.
+		 */
+		if (buf->base == NULL && buf->len == 0) {
+			return;
+		}
+	}
+
+	isc__nm_free_uvbuf(sock, buf);
+}
+
+static void
+quota_accept_cb(isc_quota_t *quota, void *sock0) {
+	isc_nmsocket_t *sock = (isc_nmsocket_t *)sock0;
+
+	REQUIRE(VALID_NMSOCK(sock));
+
+	/*
+	 * Create a tcpdnsaccept event and pass it using the async channel.
+	 */
+
+	isc__netievent_tcpdnsaccept_t *ievent =
+		isc__nm_get_netievent_tcpdnsaccept(sock->mgr, sock, quota);
+	isc__nm_maybe_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				     (isc__netievent_t *)ievent);
+}
+
+/*
+ * This is called after we get a quota_accept_cb() callback.
+ */
+void
+isc__nm_async_tcpdnsaccept(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpdnsaccept_t *ievent =
+		(isc__netievent_tcpdnsaccept_t *)ev0;
+	isc_result_t result;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(ievent->sock));
+	REQUIRE(ievent->sock->tid == isc_nm_tid());
+
+	result = accept_connection(ievent->sock, ievent->quota);
+	isc__nm_accept_connection_log(result, can_log_tcpdns_quota());
+}
+
+static isc_result_t
+accept_connection(isc_nmsocket_t *ssock, isc_quota_t *quota) {
+	isc_nmsocket_t *csock = NULL;
+	isc__networker_t *worker = NULL;
+	int r;
+	isc_result_t result;
+	struct sockaddr_storage peer_ss;
+	struct sockaddr_storage local_ss;
+	isc_sockaddr_t local;
+	isc_nmhandle_t *handle = NULL;
+
+	REQUIRE(VALID_NMSOCK(ssock));
+	REQUIRE(ssock->tid == isc_nm_tid());
+
+	if (isc__nmsocket_closing(ssock)) {
+		if (quota != NULL) {
+			isc_quota_detach(&quota);
+		}
+		return (ISC_R_CANCELED);
+	}
+
+	REQUIRE(ssock->accept_cb != NULL);
+
+	csock = isc_mem_get(ssock->mgr->mctx, sizeof(isc_nmsocket_t));
+	isc__nmsocket_init(csock, ssock->mgr, isc_nm_tcpdnssocket,
+			   &ssock->iface);
+	csock->tid = ssock->tid;
+	csock->extrahandlesize = ssock->extrahandlesize;
+	isc__nmsocket_attach(ssock, &csock->server);
+	csock->recv_cb = ssock->recv_cb;
+	csock->recv_cbarg = ssock->recv_cbarg;
+	csock->quota = quota;
+	csock->accepting = true;
+
+	worker = &csock->mgr->workers[csock->tid];
+
+	r = uv_tcp_init(&worker->loop, &csock->uv_handle.tcp);
+	UV_RUNTIME_CHECK(uv_tcp_init, r);
+	uv_handle_set_data(&csock->uv_handle.handle, csock);
+
+	r = uv_timer_init(&worker->loop, &csock->read_timer);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
+	uv_handle_set_data((uv_handle_t *)&csock->read_timer, csock);
+
+	r = uv_accept(&ssock->uv_handle.stream, &csock->uv_handle.stream);
+	if (r != 0) {
+		result = isc__nm_uverr2result(r);
+		goto failure;
+	}
+
+	r = uv_tcp_getpeername(&csock->uv_handle.tcp,
+			       (struct sockaddr *)&peer_ss,
+			       &(int){ sizeof(peer_ss) });
+	if (r != 0) {
+		result = isc__nm_uverr2result(r);
+		goto failure;
+	}
+
+	result = isc_sockaddr_fromsockaddr(&csock->peer,
+					   (struct sockaddr *)&peer_ss);
+	if (result != ISC_R_SUCCESS) {
+		goto failure;
+	}
+
+	r = uv_tcp_getsockname(&csock->uv_handle.tcp,
+			       (struct sockaddr *)&local_ss,
+			       &(int){ sizeof(local_ss) });
+	if (r != 0) {
+		result = isc__nm_uverr2result(r);
+		goto failure;
+	}
+
+	result = isc_sockaddr_fromsockaddr(&local,
+					   (struct sockaddr *)&local_ss);
+	if (result != ISC_R_SUCCESS) {
+		goto failure;
+	}
+
+	/*
+	 * The handle will be either detached on acceptcb failure or in the
+	 * readcb.
+	 */
+	handle = isc__nmhandle_get(csock, NULL, &local);
+
+	result = ssock->accept_cb(handle, ISC_R_SUCCESS, ssock->accept_cbarg);
+	if (result != ISC_R_SUCCESS) {
+		isc_nmhandle_detach(&handle);
+		goto failure;
+	}
+
+	csock->accepting = false;
+
+	isc__nm_incstats(csock->mgr, csock->statsindex[STATID_ACCEPT]);
+
+	csock->read_timeout = atomic_load(&csock->mgr->init);
+
+	csock->closehandle_cb = isc__nm_resume_processing;
+
+	/*
+	 * We need to keep the handle alive until we fail to read or connection
+	 * is closed by the other side, it will be detached via
+	 * prep_destroy()->tcpdns_close_direct().
+	 */
+	isc_nmhandle_attach(handle, &csock->recv_handle);
+	result = isc__nm_process_sock_buffer(csock);
+	if (result != ISC_R_SUCCESS) {
+		isc_nmhandle_detach(&csock->recv_handle);
+		isc_nmhandle_detach(&handle);
+		goto failure;
+	}
+
+	/*
+	 * The initial timer has been set, update the read timeout for the next
+	 * reads.
+	 */
+	csock->read_timeout = (atomic_load(&csock->keepalive)
+				       ? atomic_load(&csock->mgr->keepalive)
+				       : atomic_load(&csock->mgr->idle));
+
+	isc_nmhandle_detach(&handle);
+
+	/*
+	 * sock is now attached to the handle.
+	 */
+	isc__nmsocket_detach(&csock);
+
+	return (ISC_R_SUCCESS);
+
+failure:
+
+	atomic_store(&csock->active, false);
+
+	isc__nm_failed_accept_cb(csock, result);
+
+	isc__nmsocket_prep_destroy(csock);
+
+	isc__nmsocket_detach(&csock);
+
+	return (result);
+}
+
+void
+isc__nm_tcpdns_send(isc_nmhandle_t *handle, isc_region_t *region,
+		    isc_nm_cb_t cb, void *cbarg) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	isc_nmsocket_t *sock = handle->sock;
+	isc__netievent_tcpdnssend_t *ievent = NULL;
+	isc__nm_uvreq_t *uvreq = NULL;
+
+	REQUIRE(sock->type == isc_nm_tcpdnssocket);
+
+	uvreq = isc__nm_uvreq_get(sock->mgr, sock);
+	*(uint16_t *)uvreq->tcplen = htons(region->length);
+	uvreq->uvbuf.base = (char *)region->base;
+	uvreq->uvbuf.len = region->length;
+
+	isc_nmhandle_attach(handle, &uvreq->handle);
+
+	uvreq->cb.send = cb;
+	uvreq->cbarg = cbarg;
+
+	ievent = isc__nm_get_netievent_tcpdnssend(sock->mgr, sock, uvreq);
+	isc__nm_maybe_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				     (isc__netievent_t *)ievent);
+
+	return;
+}
+
+static void
+tcpdns_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_NMSOCK(uvreq->sock));
+
+	sock = uvreq->sock;
+
+	isc_nm_timer_stop(uvreq->timer);
+	isc_nm_timer_detach(&uvreq->timer);
+
+	if (status < 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
+		isc__nm_failed_send_cb(sock, uvreq,
+				       isc__nm_uverr2result(status));
+		return;
+	}
+
+	isc__nm_sendcb(sock, uvreq, ISC_R_SUCCESS, false);
+}
+
+/*
+ * Handle 'tcpsend' async event - send a packet on the socket
+ */
+void
+isc__nm_async_tcpdnssend(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpdnssend_t *ievent =
+		(isc__netievent_tcpdnssend_t *)ev0;
+
+	REQUIRE(VALID_UVREQ(ievent->req));
+	REQUIRE(VALID_NMSOCK(ievent->sock));
+	REQUIRE(ievent->sock->type == isc_nm_tcpdnssocket);
+	REQUIRE(ievent->sock->tid == isc_nm_tid());
+
+	isc_result_t result;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc__nm_uvreq_t *uvreq = ievent->req;
+
+	if (sock->write_timeout == 0) {
+		sock->write_timeout =
+			(atomic_load(&sock->keepalive)
+				 ? atomic_load(&sock->mgr->keepalive)
+				 : atomic_load(&sock->mgr->idle));
+	}
+
+	uv_buf_t bufs[2] = { { .base = uvreq->tcplen, .len = 2 },
+			     { .base = uvreq->uvbuf.base,
+			       .len = uvreq->uvbuf.len } };
+	int nbufs = 2;
+	int r;
+
+	UNUSED(worker);
+
+	if (isc__nmsocket_closing(sock)) {
+		result = ISC_R_CANCELED;
+		goto fail;
+	}
+
+	r = uv_try_write(&sock->uv_handle.stream, bufs, nbufs);
+
+	if (r == (int)(bufs[0].len + bufs[1].len)) {
+		/* Wrote everything */
+		isc__nm_sendcb(sock, uvreq, ISC_R_SUCCESS, true);
+		return;
+	}
+
+	if (r == 1) {
+		/* Partial write of DNSMSG length */
+		bufs[0].base = uvreq->tcplen + 1;
+		bufs[0].len = 1;
+	} else if (r > 0) {
+		/* Partial write of DNSMSG */
+		nbufs = 1;
+		bufs[0].base = uvreq->uvbuf.base + (r - 2);
+		bufs[0].len = uvreq->uvbuf.len - (r - 2);
+	} else if (r == UV_ENOSYS || r == UV_EAGAIN) {
+		/* uv_try_write not supported, send asynchronously */
+	} else {
+		/* error sending data */
+		result = isc__nm_uverr2result(r);
+		goto fail;
+	}
+
+	r = uv_write(&uvreq->uv_req.write, &sock->uv_handle.stream, bufs, nbufs,
+		     tcpdns_send_cb);
+	if (r < 0) {
+		result = isc__nm_uverr2result(r);
+		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:
+	if (result != ISC_R_SUCCESS) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
+		isc__nm_failed_send_cb(sock, uvreq, result);
+	}
+}
+
+static void
+tcpdns_stop_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->closing));
+
+	uv_handle_set_data(handle, NULL);
+
+	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
+					    true))
+	{
+		UNREACHABLE();
+	}
+
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CLOSE]);
+
+	atomic_store(&sock->listening, false);
+
+	isc__nmsocket_detach(&sock);
+}
+
+static void
+tcpdns_close_sock(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->closing));
+
+	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
+					    true))
+	{
+		UNREACHABLE();
+	}
+
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CLOSE]);
+
+	if (sock->server != NULL) {
+		isc__nmsocket_detach(&sock->server);
+	}
+
+	atomic_store(&sock->connected, false);
+
+	isc__nmsocket_prep_destroy(sock);
+}
+
+static void
+tcpdns_close_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+
+	uv_handle_set_data(handle, NULL);
+
+	tcpdns_close_sock(sock);
+}
+
+static void
+read_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));
+
+	if (sock->parent) {
+		uv_close(&sock->uv_handle.handle, tcpdns_stop_cb);
+	} else if (uv_is_closing(&sock->uv_handle.handle)) {
+		tcpdns_close_sock(sock);
+	} else {
+		uv_close(&sock->uv_handle.handle, tcpdns_close_cb);
+	}
+}
+
+static void
+stop_tcpdns_child(isc_nmsocket_t *sock) {
+	REQUIRE(sock->type == isc_nm_tcpdnssocket);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
+					    true))
+	{
+		return;
+	}
+
+	tcpdns_close_direct(sock);
+
+	atomic_fetch_sub(&sock->parent->rchildren, 1);
+
+	isc_barrier_wait(&sock->parent->stoplistening);
+}
+
+static void
+stop_tcpdns_parent(isc_nmsocket_t *sock) {
+	isc_nmsocket_t *csock = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->type == isc_nm_tcpdnslistener);
+
+	isc_barrier_init(&sock->stoplistening, sock->nchildren);
+
+	for (size_t i = 0; i < sock->nchildren; i++) {
+		csock = &sock->children[i];
+		REQUIRE(VALID_NMSOCK(csock));
+
+		if ((int)i == isc_nm_tid()) {
+			/*
+			 * We need to schedule closing the other sockets first
+			 */
+			continue;
+		}
+
+		atomic_store(&csock->active, false);
+		enqueue_stoplistening(csock);
+	}
+
+	csock = &sock->children[isc_nm_tid()];
+	atomic_store(&csock->active, false);
+	stop_tcpdns_child(csock);
+
+	atomic_store(&sock->closed, true);
+	isc__nmsocket_prep_destroy(sock);
+}
+
+static void
+tcpdns_close_direct(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->closing));
+
+	if (sock->quota != NULL) {
+		isc_quota_detach(&sock->quota);
+	}
+
+	if (sock->recv_handle != NULL) {
+		isc_nmhandle_detach(&sock->recv_handle);
+	}
+
+	isc__nmsocket_timer_stop(sock);
+	isc__nm_stop_reading(sock);
+
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
+}
+
+void
+isc__nm_tcpdns_close(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_tcpdnssocket);
+	REQUIRE(!isc__nmsocket_active(sock));
+
+	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
+					    true))
+	{
+		return;
+	}
+
+	if (sock->tid == isc_nm_tid()) {
+		tcpdns_close_direct(sock);
+	} else {
+		/*
+		 * We need to create an event and pass it using async channel
+		 */
+		isc__netievent_tcpdnsclose_t *ievent =
+			isc__nm_get_netievent_tcpdnsclose(sock->mgr, sock);
+
+		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+}
+
+void
+isc__nm_async_tcpdnsclose(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpdnsclose_t *ievent =
+		(isc__netievent_tcpdnsclose_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	tcpdns_close_direct(sock);
+}
+
+static void
+tcpdns_close_connect_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+
+	REQUIRE(VALID_NMSOCK(sock));
+
+	REQUIRE(isc__nm_in_netthread());
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	isc__nmsocket_prep_destroy(sock);
+	isc__nmsocket_detach(&sock);
+}
+
+void
+isc__nm_tcpdns_shutdown(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->type == isc_nm_tcpdnssocket);
+
+	/*
+	 * If the socket is active, mark it inactive and
+	 * continue. If it isn't active, stop now.
+	 */
+	if (!isc__nmsocket_deactivate(sock)) {
+		return;
+	}
+
+	if (sock->accepting) {
+		return;
+	}
+
+	if (atomic_load(&sock->connecting)) {
+		isc_nmsocket_t *tsock = NULL;
+		isc__nmsocket_attach(sock, &tsock);
+		uv_close(&sock->uv_handle.handle, tcpdns_close_connect_cb);
+		return;
+	}
+
+	if (sock->statichandle != NULL) {
+		isc__nm_failed_read_cb(sock, ISC_R_CANCELED, false);
+		return;
+	}
+
+	/*
+	 * Otherwise, we just send the socket to abyss...
+	 */
+	if (sock->parent == NULL) {
+		isc__nmsocket_prep_destroy(sock);
+	}
+}
+
+void
+isc__nm_tcpdns_cancelread(isc_nmhandle_t *handle) {
+	isc_nmsocket_t *sock = NULL;
+	isc__netievent_tcpdnscancel_t *ievent = NULL;
+
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	sock = handle->sock;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_tcpdnssocket);
+
+	ievent = isc__nm_get_netievent_tcpdnscancel(sock->mgr, sock, handle);
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+}
+
+void
+isc__nm_async_tcpdnscancel(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_tcpdnscancel_t *ievent =
+		(isc__netievent_tcpdnscancel_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	isc__nm_failed_read_cb(sock, ISC_R_EOF, false);
+}
+
+void
+isc_nm_tcpdns_sequential(isc_nmhandle_t *handle) {
+	isc_nmsocket_t *sock = NULL;
+
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+	REQUIRE(handle->sock->type == isc_nm_tcpdnssocket);
+
+	sock = handle->sock;
+
+	/*
+	 * We don't want pipelining on this connection. That means
+	 * that we need to pause after reading each request, and
+	 * resume only after the request has been processed. This
+	 * is done in resume_processing(), which is the socket's
+	 * closehandle_cb callback, called whenever a handle
+	 * is released.
+	 */
+
+	isc__nmsocket_timer_stop(sock);
+	isc__nm_stop_reading(sock);
+	atomic_store(&sock->sequential, true);
+}
diff --git a/lib/isc/netmgr/udp.c b/lib/isc/netmgr/udp.c
new file mode 100644
index 0000000..00f9d40
--- /dev/null
+++ b/lib/isc/netmgr/udp.c
@@ -0,0 +1,1211 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <unistd.h>
+#include <uv.h>
+
+#include <isc/atomic.h>
+#include <isc/barrier.h>
+#include <isc/buffer.h>
+#include <isc/condition.h>
+#include <isc/errno.h>
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/netmgr.h>
+#include <isc/random.h>
+#include <isc/refcount.h>
+#include <isc/region.h>
+#include <isc/result.h>
+#include <isc/sockaddr.h>
+#include <isc/thread.h>
+#include <isc/util.h>
+
+#include "netmgr-int.h"
+#include "uv-compat.h"
+
+static isc_result_t
+udp_send_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
+		isc_sockaddr_t *peer);
+
+static void
+udp_recv_cb(uv_udp_t *handle, ssize_t nrecv, const uv_buf_t *buf,
+	    const struct sockaddr *addr, unsigned flags);
+
+static void
+udp_send_cb(uv_udp_send_t *req, int status);
+
+static void
+udp_close_cb(uv_handle_t *handle);
+
+static void
+read_timer_close_cb(uv_handle_t *handle);
+
+static void
+udp_close_direct(isc_nmsocket_t *sock);
+
+static void
+stop_udp_parent(isc_nmsocket_t *sock);
+static void
+stop_udp_child(isc_nmsocket_t *sock);
+
+static uv_os_sock_t
+isc__nm_udp_lb_socket(isc_nm_t *mgr, sa_family_t sa_family) {
+	isc_result_t result;
+	uv_os_sock_t sock;
+
+	result = isc__nm_socket(sa_family, SOCK_DGRAM, 0, &sock);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+	(void)isc__nm_socket_incoming_cpu(sock);
+	(void)isc__nm_socket_disable_pmtud(sock, sa_family);
+
+	result = isc__nm_socket_reuse(sock);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+#ifndef _WIN32
+	if (mgr->load_balance_sockets) {
+		result = isc__nm_socket_reuse_lb(sock);
+		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+	}
+#endif
+
+	return (sock);
+}
+
+static void
+start_udp_child(isc_nm_t *mgr, isc_sockaddr_t *iface, isc_nmsocket_t *sock,
+		uv_os_sock_t fd, int tid) {
+	isc_nmsocket_t *csock;
+	isc__netievent_udplisten_t *ievent = NULL;
+
+	csock = &sock->children[tid];
+
+	isc__nmsocket_init(csock, mgr, isc_nm_udpsocket, iface);
+	csock->parent = sock;
+	csock->iface = sock->iface;
+	csock->reading = true;
+	csock->recv_cb = sock->recv_cb;
+	csock->recv_cbarg = sock->recv_cbarg;
+	csock->extrahandlesize = sock->extrahandlesize;
+	csock->tid = tid;
+
+#ifdef _WIN32
+	UNUSED(fd);
+	csock->fd = isc__nm_udp_lb_socket(mgr, iface->type.sa.sa_family);
+#else
+	if (mgr->load_balance_sockets) {
+		UNUSED(fd);
+		csock->fd = isc__nm_udp_lb_socket(mgr,
+						  iface->type.sa.sa_family);
+	} else {
+		csock->fd = dup(fd);
+	}
+#endif
+	REQUIRE(csock->fd >= 0);
+
+	ievent = isc__nm_get_netievent_udplisten(mgr, csock);
+	isc__nm_maybe_enqueue_ievent(&mgr->workers[tid],
+				     (isc__netievent_t *)ievent);
+}
+
+static void
+enqueue_stoplistening(isc_nmsocket_t *sock) {
+	isc__netievent_udpstop_t *ievent =
+		isc__nm_get_netievent_udpstop(sock->mgr, sock);
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+}
+
+isc_result_t
+isc_nm_listenudp(isc_nm_t *mgr, isc_sockaddr_t *iface, isc_nm_recv_cb_t cb,
+		 void *cbarg, size_t extrahandlesize, isc_nmsocket_t **sockp) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc_nmsocket_t *sock = NULL;
+	size_t children_size = 0;
+	REQUIRE(VALID_NM(mgr));
+	uv_os_sock_t fd = -1;
+
+	/*
+	 * We are creating mgr->nworkers duplicated sockets, one
+	 * socket for each worker thread.
+	 */
+	sock = isc_mem_get(mgr->mctx, sizeof(isc_nmsocket_t));
+	isc__nmsocket_init(sock, mgr, isc_nm_udplistener, iface);
+
+	atomic_init(&sock->rchildren, 0);
+#if defined(WIN32)
+	sock->nchildren = 1;
+#else
+	sock->nchildren = mgr->nworkers;
+#endif
+
+	children_size = sock->nchildren * sizeof(sock->children[0]);
+	sock->children = isc_mem_get(mgr->mctx, children_size);
+	memset(sock->children, 0, children_size);
+
+	sock->recv_cb = cb;
+	sock->recv_cbarg = cbarg;
+	sock->extrahandlesize = extrahandlesize;
+	sock->result = ISC_R_UNSET;
+
+	sock->tid = 0;
+	sock->fd = -1;
+
+#ifndef _WIN32
+	if (!mgr->load_balance_sockets) {
+		fd = isc__nm_udp_lb_socket(mgr, iface->type.sa.sa_family);
+	}
+#endif
+
+	isc_barrier_init(&sock->startlistening, sock->nchildren);
+
+	for (size_t i = 0; i < sock->nchildren; i++) {
+		if ((int)i == isc_nm_tid()) {
+			continue;
+		}
+		start_udp_child(mgr, iface, sock, fd, i);
+	}
+
+	if (isc__nm_in_netthread()) {
+		start_udp_child(mgr, iface, sock, fd, isc_nm_tid());
+	}
+
+#ifndef _WIN32
+	if (!mgr->load_balance_sockets) {
+		isc__nm_closesocket(fd);
+	}
+#endif
+
+	LOCK(&sock->lock);
+	while (atomic_load(&sock->rchildren) != sock->nchildren) {
+		WAIT(&sock->cond, &sock->lock);
+	}
+	result = sock->result;
+	atomic_store(&sock->active, true);
+	UNLOCK(&sock->lock);
+
+	INSIST(result != ISC_R_UNSET);
+
+	if (result == ISC_R_SUCCESS) {
+		REQUIRE(atomic_load(&sock->rchildren) == sock->nchildren);
+		*sockp = sock;
+	} else {
+		atomic_store(&sock->active, false);
+		enqueue_stoplistening(sock);
+		isc_nmsocket_close(&sock);
+	}
+
+	return (result);
+}
+
+/*
+ * Asynchronous 'udplisten' call handler: start listening on a UDP socket.
+ */
+void
+isc__nm_async_udplisten(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_udplisten_t *ievent = (isc__netievent_udplisten_t *)ev0;
+	isc_nmsocket_t *sock = NULL;
+	int r, uv_bind_flags = 0;
+	int uv_init_flags = 0;
+	sa_family_t sa_family;
+	isc_result_t result = ISC_R_UNSET;
+	isc_nm_t *mgr = NULL;
+
+	REQUIRE(VALID_NMSOCK(ievent->sock));
+	REQUIRE(ievent->sock->tid == isc_nm_tid());
+	REQUIRE(VALID_NMSOCK(ievent->sock->parent));
+
+	sock = ievent->sock;
+	sa_family = sock->iface.type.sa.sa_family;
+	mgr = sock->mgr;
+
+	REQUIRE(sock->type == isc_nm_udpsocket);
+	REQUIRE(sock->parent != NULL);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+#if HAVE_DECL_UV_UDP_RECVMMSG
+	uv_init_flags |= UV_UDP_RECVMMSG;
+#endif
+	r = uv_udp_init_ex(&worker->loop, &sock->uv_handle.udp, uv_init_flags);
+	UV_RUNTIME_CHECK(uv_udp_init_ex, r);
+	uv_handle_set_data(&sock->uv_handle.handle, sock);
+	/* This keeps the socket alive after everything else is gone */
+	isc__nmsocket_attach(sock, &(isc_nmsocket_t *){ NULL });
+
+	r = uv_timer_init(&worker->loop, &sock->read_timer);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+
+	LOCK(&sock->parent->lock);
+
+	r = uv_udp_open(&sock->uv_handle.udp, sock->fd);
+	if (r < 0) {
+		isc__nm_closesocket(sock->fd);
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPENFAIL]);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPEN]);
+
+	if (sa_family == AF_INET6) {
+		uv_bind_flags |= UV_UDP_IPV6ONLY;
+	}
+
+#ifdef _WIN32
+	r = isc_uv_udp_freebind(&sock->uv_handle.udp,
+				&sock->parent->iface.type.sa, uv_bind_flags);
+	if (r < 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_BINDFAIL]);
+		goto done;
+	}
+#else
+	if (mgr->load_balance_sockets) {
+		r = isc_uv_udp_freebind(&sock->uv_handle.udp,
+					&sock->parent->iface.type.sa,
+					uv_bind_flags);
+		if (r < 0) {
+			isc__nm_incstats(sock->mgr,
+					 sock->statsindex[STATID_BINDFAIL]);
+			goto done;
+		}
+	} else {
+		if (sock->parent->fd == -1) {
+			/* This thread is first, bind the socket */
+			r = isc_uv_udp_freebind(&sock->uv_handle.udp,
+						&sock->parent->iface.type.sa,
+						uv_bind_flags);
+			if (r < 0) {
+				isc__nm_incstats(sock->mgr, STATID_BINDFAIL);
+				goto done;
+			}
+			sock->parent->uv_handle.udp.flags =
+				sock->uv_handle.udp.flags;
+			sock->parent->fd = sock->fd;
+		} else {
+			/* The socket is already bound, just copy the flags */
+			sock->uv_handle.udp.flags =
+				sock->parent->uv_handle.udp.flags;
+		}
+	}
+#endif
+
+#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
+	r = uv_udp_recv_start(&sock->uv_handle.udp, isc__nm_alloc_cb,
+			      udp_recv_cb);
+	if (r != 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_BINDFAIL]);
+		goto done;
+	}
+
+	atomic_store(&sock->listening, true);
+
+done:
+	result = isc__nm_uverr2result(r);
+	atomic_fetch_add(&sock->parent->rchildren, 1);
+	if (sock->parent->result == ISC_R_UNSET) {
+		sock->parent->result = result;
+	}
+	SIGNAL(&sock->parent->cond);
+	UNLOCK(&sock->parent->lock);
+
+	isc_barrier_wait(&sock->parent->startlistening);
+}
+
+void
+isc__nm_udp_stoplistening(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_udplistener);
+
+	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
+					    true))
+	{
+		UNREACHABLE();
+	}
+
+	if (!isc__nm_in_netthread()) {
+		enqueue_stoplistening(sock);
+	} else {
+		stop_udp_parent(sock);
+	}
+}
+
+/*
+ * Asynchronous 'udpstop' call handler: stop listening on a UDP socket.
+ */
+void
+isc__nm_async_udpstop(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_udpstop_t *ievent = (isc__netievent_udpstop_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (sock->parent != NULL) {
+		stop_udp_child(sock);
+		return;
+	}
+
+	stop_udp_parent(sock);
+}
+
+/*
+ * udp_recv_cb handles incoming UDP packet from uv.  The buffer here is
+ * reused for a series of packets, so we need to allocate a new one.
+ * This new one can be reused to send the response then.
+ */
+static void
+udp_recv_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);
+	isc__nm_uvreq_t *req = NULL;
+	uint32_t maxudp;
+	isc_sockaddr_t sockaddr;
+	isc_result_t result;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->reading);
+
+	/*
+	 * When using recvmmsg(2), if no errors occur, there will be a final
+	 * callback with nrecv set to 0, addr set to NULL and the buffer
+	 * pointing at the initially allocated data with the UV_UDP_MMSG_CHUNK
+	 * flag cleared and the UV_UDP_MMSG_FREE flag set.
+	 */
+#if HAVE_DECL_UV_UDP_MMSG_FREE
+	if ((flags & UV_UDP_MMSG_FREE) == UV_UDP_MMSG_FREE) {
+		INSIST(nrecv == 0);
+		INSIST(addr == NULL);
+		goto free;
+	}
+#else
+	UNUSED(flags);
+#endif
+
+	/*
+	 * - If we're simulating a firewall blocking UDP packets
+	 *   bigger than 'maxudp' bytes for testing purposes.
+	 */
+	maxudp = atomic_load(&sock->mgr->maxudp);
+	if ((maxudp != 0 && (uint32_t)nrecv > maxudp)) {
+		/*
+		 * We need to keep the read_cb intact in case, so the
+		 * readtimeout_cb can trigger and not crash because of
+		 * missing read_req.
+		 */
+		goto free;
+	}
+
+	/*
+	 * - If addr == NULL, in which case it's the end of stream;
+	 *   we can free the buffer and bail.
+	 */
+	if (addr == NULL) {
+		isc__nm_failed_read_cb(sock, ISC_R_EOF, false);
+		goto free;
+	}
+
+	/*
+	 * - If the socket is no longer active.
+	 */
+	if (!isc__nmsocket_active(sock)) {
+		isc__nm_failed_read_cb(sock, ISC_R_CANCELED, false);
+		goto free;
+	}
+
+	if (nrecv < 0) {
+		isc__nm_failed_read_cb(sock, isc__nm_uverr2result(nrecv),
+				       false);
+		goto free;
+	}
+
+	result = isc_sockaddr_fromsockaddr(&sockaddr, addr);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+
+	req = isc__nm_get_read_req(sock, &sockaddr);
+
+	/*
+	 * The callback will be called synchronously, because result is
+	 * ISC_R_SUCCESS, so we are ok of passing the buf directly.
+	 */
+	req->uvbuf.base = buf->base;
+	req->uvbuf.len = nrecv;
+
+	sock->recv_read = false;
+
+	REQUIRE(!sock->processing);
+	sock->processing = true;
+	isc__nm_readcb(sock, req, ISC_R_SUCCESS);
+	sock->processing = false;
+
+free:
+#if HAVE_DECL_UV_UDP_MMSG_CHUNK
+	/*
+	 * When using recvmmsg(2), chunks will have the UV_UDP_MMSG_CHUNK flag
+	 * set, those must not be freed.
+	 */
+	if ((flags & UV_UDP_MMSG_CHUNK) == UV_UDP_MMSG_CHUNK) {
+		return;
+	}
+#endif
+
+	/*
+	 * When using recvmmsg(2), if a UDP socket error occurs, nrecv will be <
+	 * 0. In either scenario, the callee can now safely free the provided
+	 * buffer.
+	 */
+	if (nrecv < 0) {
+		/*
+		 * The buffer may be a null buffer on error.
+		 */
+		if (buf->base == NULL && buf->len == 0) {
+			return;
+		}
+	}
+
+	isc__nm_free_uvbuf(sock, buf);
+}
+
+/*
+ * Send the data in 'region' to a peer via a UDP socket. We try to find
+ * a proper sibling/child socket so that we won't have to jump to
+ * another thread.
+ */
+void
+isc__nm_udp_send(isc_nmhandle_t *handle, const isc_region_t *region,
+		 isc_nm_cb_t cb, void *cbarg) {
+	isc_nmsocket_t *sock = handle->sock;
+	isc_nmsocket_t *rsock = NULL;
+	isc_sockaddr_t *peer = &handle->peer;
+	isc__nm_uvreq_t *uvreq = NULL;
+	uint32_t maxudp = atomic_load(&sock->mgr->maxudp);
+	int ntid;
+
+	INSIST(sock->type == isc_nm_udpsocket);
+
+	/*
+	 * We're simulating a firewall blocking UDP packets bigger than
+	 * 'maxudp' bytes, for testing purposes.
+	 *
+	 * The client would ordinarily have unreferenced the handle
+	 * in the callback, but that won't happen in this case, so
+	 * we need to do so here.
+	 */
+	if (maxudp != 0 && region->length > maxudp) {
+		isc_nmhandle_detach(&handle);
+		return;
+	}
+
+	if (atomic_load(&sock->client)) {
+		/*
+		 * When we are sending from the client socket, we directly use
+		 * the socket provided.
+		 */
+		rsock = sock;
+		goto send;
+	} else {
+		/*
+		 * When we are sending from the server socket, we either use the
+		 * socket associated with the network thread we are in, or we
+		 * use the thread from the socket associated with the handle.
+		 */
+		INSIST(sock->parent != NULL);
+
+#if defined(WIN32)
+		/* On Windows, we have only a single listening listener */
+		rsock = sock;
+#else
+		if (isc__nm_in_netthread()) {
+			ntid = isc_nm_tid();
+		} else {
+			ntid = sock->tid;
+		}
+		rsock = &sock->parent->children[ntid];
+#endif
+	}
+
+send:
+	uvreq = isc__nm_uvreq_get(rsock->mgr, rsock);
+	uvreq->uvbuf.base = (char *)region->base;
+	uvreq->uvbuf.len = region->length;
+
+	isc_nmhandle_attach(handle, &uvreq->handle);
+
+	uvreq->cb.send = cb;
+	uvreq->cbarg = cbarg;
+
+	if (isc_nm_tid() == rsock->tid) {
+		REQUIRE(rsock->tid == isc_nm_tid());
+		isc__netievent_udpsend_t ievent = { .sock = rsock,
+						    .req = uvreq,
+						    .peer = *peer };
+
+		isc__nm_async_udpsend(NULL, (isc__netievent_t *)&ievent);
+	} else {
+		isc__netievent_udpsend_t *ievent =
+			isc__nm_get_netievent_udpsend(sock->mgr, rsock);
+		ievent->peer = *peer;
+		ievent->req = uvreq;
+
+		isc__nm_enqueue_ievent(&sock->mgr->workers[rsock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+}
+
+/*
+ * Asynchronous 'udpsend' event handler: send a packet on a UDP socket.
+ */
+void
+isc__nm_async_udpsend(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc_result_t result;
+	isc__netievent_udpsend_t *ievent = (isc__netievent_udpsend_t *)ev0;
+	isc_nmsocket_t *sock = ievent->sock;
+	isc__nm_uvreq_t *uvreq = ievent->req;
+
+	REQUIRE(sock->type == isc_nm_udpsocket);
+	REQUIRE(sock->tid == isc_nm_tid());
+	UNUSED(worker);
+
+	if (isc__nmsocket_closing(sock)) {
+		isc__nm_failed_send_cb(sock, uvreq, ISC_R_CANCELED);
+		return;
+	}
+
+	result = udp_send_direct(sock, uvreq, &ievent->peer);
+	if (result != ISC_R_SUCCESS) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
+		isc__nm_failed_send_cb(sock, uvreq, result);
+	}
+}
+
+static void
+udp_send_cb(uv_udp_send_t *req, int status) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc__nm_uvreq_t *uvreq = uv_handle_get_data((uv_handle_t *)req);
+	isc_nmsocket_t *sock = NULL;
+
+	REQUIRE(VALID_UVREQ(uvreq));
+	REQUIRE(VALID_NMHANDLE(uvreq->handle));
+
+	sock = uvreq->sock;
+
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (status < 0) {
+		result = isc__nm_uverr2result(status);
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_SENDFAIL]);
+	}
+
+	isc__nm_sendcb(sock, uvreq, result, false);
+}
+
+/*
+ * udp_send_direct sends buf to a peer on a socket. Sock has to be in
+ * the same thread as the callee.
+ */
+static isc_result_t
+udp_send_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req,
+		isc_sockaddr_t *peer) {
+	const struct sockaddr *sa = &peer->type.sa;
+	int r;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(VALID_UVREQ(req));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->type == isc_nm_udpsocket);
+
+	if (isc__nmsocket_closing(sock)) {
+		return (ISC_R_CANCELED);
+	}
+
+#if UV_VERSION_HEX >= UV_VERSION(1, 27, 0)
+	/*
+	 * If we used uv_udp_connect() (and not the shim version for
+	 * older versions of libuv), then the peer address has to be
+	 * set to NULL or else uv_udp_send() could fail or assert,
+	 * depending on the libuv version.
+	 */
+	if (atomic_load(&sock->connected)) {
+		sa = NULL;
+	}
+#endif
+
+	r = uv_udp_send(&req->uv_req.udp_send, &sock->uv_handle.udp,
+			&req->uvbuf, 1, sa, udp_send_cb);
+	if (r < 0) {
+		return (isc__nm_uverr2result(r));
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+udp_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
+	isc__networker_t *worker = NULL;
+	int uv_bind_flags = UV_UDP_REUSEADDR;
+	isc_result_t result = ISC_R_UNSET;
+	int tries = 3;
+	int r;
+
+	REQUIRE(isc__nm_in_netthread());
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	worker = &sock->mgr->workers[isc_nm_tid()];
+
+	atomic_store(&sock->connecting, true);
+
+	r = uv_udp_init(&worker->loop, &sock->uv_handle.udp);
+	UV_RUNTIME_CHECK(uv_udp_init, r);
+	uv_handle_set_data(&sock->uv_handle.handle, sock);
+
+	r = uv_timer_init(&worker->loop, &sock->read_timer);
+	UV_RUNTIME_CHECK(uv_timer_init, r);
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+
+	r = uv_udp_open(&sock->uv_handle.udp, sock->fd);
+	if (r != 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPENFAIL]);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_OPEN]);
+
+	if (sock->iface.type.sa.sa_family == AF_INET6) {
+		uv_bind_flags |= UV_UDP_IPV6ONLY;
+	}
+
+	r = uv_udp_bind(&sock->uv_handle.udp, &sock->iface.type.sa,
+			uv_bind_flags);
+	if (r != 0) {
+		isc__nm_incstats(sock->mgr, sock->statsindex[STATID_BINDFAIL]);
+		goto done;
+	}
+
+#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
+
+	/*
+	 * On FreeBSD the UDP connect() call sometimes results in a
+	 * spurious transient EADDRINUSE. Try a few more times before
+	 * giving up.
+	 */
+	do {
+		r = isc_uv_udp_connect(&sock->uv_handle.udp,
+				       &req->peer.type.sa);
+	} while (r == UV_EADDRINUSE && --tries > 0);
+	if (r != 0) {
+		isc__nm_incstats(sock->mgr,
+				 sock->statsindex[STATID_CONNECTFAIL]);
+		goto done;
+	}
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CONNECT]);
+
+	atomic_store(&sock->connecting, false);
+	atomic_store(&sock->connected, true);
+
+done:
+	result = isc__nm_uverr2result(r);
+
+	LOCK(&sock->lock);
+	sock->result = result;
+	SIGNAL(&sock->cond);
+	if (!atomic_load(&sock->active)) {
+		WAIT(&sock->scond, &sock->lock);
+	}
+	INSIST(atomic_load(&sock->active));
+	UNLOCK(&sock->lock);
+
+	return (result);
+}
+
+/*
+ * 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__nm_uvreq_t *req = ievent->req;
+	isc_result_t result;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_udpsocket);
+	REQUIRE(sock->parent == NULL);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	result = udp_connect_direct(sock, req);
+	if (result != ISC_R_SUCCESS) {
+		atomic_store(&sock->active, false);
+		isc__nm_udp_close(sock);
+		isc__nm_connectcb(sock, req, result, true);
+	} else {
+		/*
+		 * The callback has to be called after the socket has been
+		 * initialized
+		 */
+		isc__nm_connectcb(sock, req, ISC_R_SUCCESS, true);
+	}
+
+	/*
+	 * The sock is now attached to the handle.
+	 */
+	isc__nmsocket_detach(&sock);
+}
+
+void
+isc_nm_udpconnect(isc_nm_t *mgr, isc_sockaddr_t *local, isc_sockaddr_t *peer,
+		  isc_nm_cb_t cb, void *cbarg, unsigned int timeout,
+		  size_t extrahandlesize) {
+	isc_result_t result = ISC_R_SUCCESS;
+	isc_nmsocket_t *sock = NULL;
+	isc__netievent_udpconnect_t *event = NULL;
+	isc__nm_uvreq_t *req = NULL;
+	sa_family_t sa_family;
+
+	REQUIRE(VALID_NM(mgr));
+	REQUIRE(local != NULL);
+	REQUIRE(peer != NULL);
+
+	sa_family = peer->type.sa.sa_family;
+
+	sock = isc_mem_get(mgr->mctx, sizeof(isc_nmsocket_t));
+	isc__nmsocket_init(sock, mgr, isc_nm_udpsocket, local);
+
+	sock->connect_cb = cb;
+	sock->connect_cbarg = cbarg;
+	sock->read_timeout = timeout;
+	sock->extrahandlesize = extrahandlesize;
+	sock->peer = *peer;
+	sock->result = ISC_R_UNSET;
+	atomic_init(&sock->client, true);
+
+	req = isc__nm_uvreq_get(mgr, sock);
+	req->cb.connect = cb;
+	req->cbarg = cbarg;
+	req->peer = *peer;
+	req->local = *local;
+	req->handle = isc__nmhandle_get(sock, &req->peer, &sock->iface);
+
+	result = isc__nm_socket(sa_family, SOCK_DGRAM, 0, &sock->fd);
+	if (result != ISC_R_SUCCESS) {
+		if (isc__nm_in_netthread()) {
+			sock->tid = isc_nm_tid();
+		}
+		isc__nmsocket_clearcb(sock);
+		isc__nm_connectcb(sock, req, result, true);
+		atomic_store(&sock->closed, true);
+		isc__nmsocket_detach(&sock);
+		return;
+	}
+
+	result = isc__nm_socket_reuse(sock->fd);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS ||
+		      result == ISC_R_NOTIMPLEMENTED);
+
+	result = isc__nm_socket_reuse_lb(sock->fd);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS ||
+		      result == ISC_R_NOTIMPLEMENTED);
+
+	(void)isc__nm_socket_incoming_cpu(sock->fd);
+
+	(void)isc__nm_socket_disable_pmtud(sock->fd, sa_family);
+
+	event = isc__nm_get_netievent_udpconnect(mgr, sock, req);
+
+	if (isc__nm_in_netthread()) {
+		atomic_store(&sock->active, true);
+		sock->tid = isc_nm_tid();
+		isc__nm_async_udpconnect(&mgr->workers[sock->tid],
+					 (isc__netievent_t *)event);
+		isc__nm_put_netievent_udpconnect(mgr, event);
+	} else {
+		atomic_init(&sock->active, false);
+		sock->tid = isc_random_uniform(mgr->nworkers);
+		isc__nm_enqueue_ievent(&mgr->workers[sock->tid],
+				       (isc__netievent_t *)event);
+	}
+	LOCK(&sock->lock);
+	while (sock->result == ISC_R_UNSET) {
+		WAIT(&sock->cond, &sock->lock);
+	}
+	atomic_store(&sock->active, true);
+	BROADCAST(&sock->scond);
+	UNLOCK(&sock->lock);
+}
+
+void
+isc__nm_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);
+	REQUIRE(VALID_NMSOCK(sock));
+
+	udp_recv_cb(handle, nrecv, buf, addr, flags);
+	/*
+	 * If a caller calls isc_nm_read() on a listening socket, we can
+	 * get here, but we MUST NOT stop reading from the listener
+	 * socket.  The only difference between listener and connected
+	 * sockets is that the former has sock->parent set and later
+	 * does not.
+	 */
+	if (!sock->parent) {
+		isc__nm_stop_reading(sock);
+	}
+}
+
+void
+isc__nm_udp_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(result != ISC_R_SUCCESS);
+
+	if (atomic_load(&sock->client)) {
+		isc__nmsocket_timer_stop(sock);
+		isc__nm_stop_reading(sock);
+
+		if (!sock->recv_read) {
+			goto destroy;
+		}
+		sock->recv_read = false;
+
+		if (sock->recv_cb != NULL) {
+			isc__nm_uvreq_t *req = isc__nm_get_read_req(sock, NULL);
+			isc__nmsocket_clearcb(sock);
+			isc__nm_readcb(sock, req, result);
+		}
+
+	destroy:
+		isc__nmsocket_prep_destroy(sock);
+		return;
+	}
+
+	/*
+	 * For UDP server socket, we don't have child socket via
+	 * "accept", so we:
+	 * - we continue to read
+	 * - we don't clear the callbacks
+	 * - we don't destroy it (only stoplistening could do that)
+	 */
+	if (!sock->recv_read) {
+		return;
+	}
+	sock->recv_read = false;
+
+	if (sock->recv_cb != NULL) {
+		isc__nm_uvreq_t *req = isc__nm_get_read_req(sock, NULL);
+		isc__nm_readcb(sock, req, result);
+	}
+}
+
+/*
+ * 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;
+	isc_result_t result;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (isc__nmsocket_closing(sock)) {
+		result = ISC_R_CANCELED;
+	} else {
+		result = isc__nm_start_reading(sock);
+	}
+
+	if (result != ISC_R_SUCCESS) {
+		sock->reading = true;
+		isc__nm_failed_read_cb(sock, result, false);
+		return;
+	}
+
+	isc__nmsocket_timer_start(sock);
+}
+
+void
+isc__nm_udp_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
+	REQUIRE(VALID_NMHANDLE(handle));
+	REQUIRE(VALID_NMSOCK(handle->sock));
+
+	isc_nmsocket_t *sock = handle->sock;
+
+	REQUIRE(sock->type == isc_nm_udpsocket);
+	REQUIRE(sock->statichandle == handle);
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(!sock->recv_read);
+
+	sock->recv_cb = cb;
+	sock->recv_cbarg = cbarg;
+	sock->recv_read = true;
+
+	if (!sock->reading && sock->tid == isc_nm_tid()) {
+		isc__netievent_udpread_t ievent = { .sock = sock };
+		isc__nm_async_udpread(NULL, (isc__netievent_t *)&ievent);
+	} else {
+		isc__netievent_udpread_t *ievent =
+			isc__nm_get_netievent_udpread(sock->mgr, sock);
+		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+}
+
+static void
+udp_stop_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+	uv_handle_set_data(handle, NULL);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->closing));
+
+	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
+					    true))
+	{
+		UNREACHABLE();
+	}
+
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CLOSE]);
+
+	atomic_store(&sock->listening, false);
+
+	isc__nmsocket_detach(&sock);
+}
+
+static void
+udp_close_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+	uv_handle_set_data(handle, NULL);
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->closing));
+
+	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
+					    true))
+	{
+		UNREACHABLE();
+	}
+
+	isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CLOSE]);
+
+	if (sock->server != NULL) {
+		isc__nmsocket_detach(&sock->server);
+	}
+
+	atomic_store(&sock->connected, false);
+	atomic_store(&sock->listening, false);
+
+	isc__nmsocket_prep_destroy(sock);
+}
+
+static void
+read_timer_close_cb(uv_handle_t *handle) {
+	isc_nmsocket_t *sock = uv_handle_get_data(handle);
+	uv_handle_set_data(handle, NULL);
+
+	if (sock->parent) {
+		uv_close(&sock->uv_handle.handle, udp_stop_cb);
+	} else {
+		uv_close(&sock->uv_handle.handle, udp_close_cb);
+	}
+}
+
+static void
+stop_udp_child(isc_nmsocket_t *sock) {
+	REQUIRE(sock->type == isc_nm_udpsocket);
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
+					    true))
+	{
+		return;
+	}
+
+	udp_close_direct(sock);
+
+	atomic_fetch_sub(&sock->parent->rchildren, 1);
+
+	isc_barrier_wait(&sock->parent->stoplistening);
+}
+
+static void
+stop_udp_parent(isc_nmsocket_t *sock) {
+	isc_nmsocket_t *csock = NULL;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->type == isc_nm_udplistener);
+
+	isc_barrier_init(&sock->stoplistening, sock->nchildren);
+
+	for (size_t i = 0; i < sock->nchildren; i++) {
+		csock = &sock->children[i];
+		REQUIRE(VALID_NMSOCK(csock));
+
+		if ((int)i == isc_nm_tid()) {
+			/*
+			 * We need to schedule closing the other sockets first
+			 */
+			continue;
+		}
+
+		atomic_store(&csock->active, false);
+		enqueue_stoplistening(csock);
+	}
+
+	csock = &sock->children[isc_nm_tid()];
+	atomic_store(&csock->active, false);
+	stop_udp_child(csock);
+
+	atomic_store(&sock->closed, true);
+	isc__nmsocket_prep_destroy(sock);
+}
+
+static void
+udp_close_direct(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+
+	uv_handle_set_data((uv_handle_t *)&sock->read_timer, sock);
+	uv_close((uv_handle_t *)&sock->read_timer, read_timer_close_cb);
+}
+
+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(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	UNUSED(worker);
+
+	udp_close_direct(sock);
+}
+
+void
+isc__nm_udp_close(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_udpsocket);
+	REQUIRE(!isc__nmsocket_active(sock));
+
+	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
+					    true))
+	{
+		return;
+	}
+
+	if (sock->tid == isc_nm_tid()) {
+		udp_close_direct(sock);
+	} else {
+		isc__netievent_udpclose_t *ievent =
+			isc__nm_get_netievent_udpclose(sock->mgr, sock);
+		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+				       (isc__netievent_t *)ievent);
+	}
+}
+
+void
+isc__nm_udp_shutdown(isc_nmsocket_t *sock) {
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(sock->type == isc_nm_udpsocket);
+
+	/*
+	 * If the socket is active, mark it inactive and
+	 * continue. If it isn't active, stop now.
+	 */
+	if (!isc__nmsocket_deactivate(sock)) {
+		return;
+	}
+
+	/*
+	 * If the socket is connecting, the cancel will happen in the
+	 * async_udpconnect() due socket being inactive now.
+	 */
+	if (atomic_load(&sock->connecting)) {
+		return;
+	}
+
+	/*
+	 * When the client detaches the last handle, the
+	 * sock->statichandle would be NULL, in that case, nobody is
+	 * interested in the callback.
+	 */
+	if (sock->statichandle != NULL) {
+		isc__nm_failed_read_cb(sock, ISC_R_CANCELED, false);
+		return;
+	}
+
+	/*
+	 * Otherwise, we just send the socket to abyss...
+	 */
+	if (sock->parent == NULL) {
+		isc__nmsocket_prep_destroy(sock);
+	}
+}
+
+void
+isc__nm_udp_cancelread(isc_nmhandle_t *handle) {
+	isc_nmsocket_t *sock = NULL;
+	isc__netievent_udpcancel_t *ievent = NULL;
+
+	REQUIRE(VALID_NMHANDLE(handle));
+
+	sock = handle->sock;
+
+	REQUIRE(VALID_NMSOCK(sock));
+	REQUIRE(sock->type == isc_nm_udpsocket);
+
+	ievent = isc__nm_get_netievent_udpcancel(sock->mgr, sock, handle);
+
+	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
+			       (isc__netievent_t *)ievent);
+}
+
+void
+isc__nm_async_udpcancel(isc__networker_t *worker, isc__netievent_t *ev0) {
+	isc__netievent_udpcancel_t *ievent = (isc__netievent_udpcancel_t *)ev0;
+	isc_nmsocket_t *sock = NULL;
+
+	UNUSED(worker);
+
+	REQUIRE(VALID_NMSOCK(ievent->sock));
+
+	sock = ievent->sock;
+
+	REQUIRE(sock->tid == isc_nm_tid());
+	REQUIRE(atomic_load(&sock->client));
+
+	isc__nm_failed_read_cb(sock, ISC_R_EOF, false);
+}
diff --git a/lib/isc/netmgr/uv-compat.c b/lib/isc/netmgr/uv-compat.c
new file mode 100644
index 0000000..a1fc309
--- /dev/null
+++ b/lib/isc/netmgr/uv-compat.c
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include "uv-compat.h"
+#include <unistd.h>
+
+#include <isc/util.h>
+
+#include "netmgr-int.h"
+
+#if UV_VERSION_HEX < UV_VERSION(1, 27, 0)
+int
+isc_uv_udp_connect(uv_udp_t *handle, const struct sockaddr *addr) {
+	int err = 0;
+
+	do {
+		int addrlen = (addr->sa_family == AF_INET)
+				      ? sizeof(struct sockaddr_in)
+				      : sizeof(struct sockaddr_in6);
+#ifdef WIN32
+		err = connect(handle->socket, addr, addrlen);
+#else  /* WIN32 */
+		err = connect(handle->io_watcher.fd, addr, addrlen);
+#endif /* WIN32 */
+	} while (err == -1 && errno == EINTR);
+
+	if (err) {
+#ifdef WIN32
+		return (uv_translate_sys_error(err));
+#else /* WIN32 */
+#if UV_VERSION_HEX >= UV_VERSION(1, 10, 0)
+		return (uv_translate_sys_error(errno));
+#else
+		return (-errno);
+#endif /* UV_VERSION_HEX >= UV_VERSION(1, 10, 0) */
+#endif /* WIN32 */
+	}
+
+	return (0);
+}
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 27, 0) */
+
+#if UV_VERSION_HEX < UV_VERSION(1, 32, 0)
+int
+uv_tcp_close_reset(uv_tcp_t *handle, uv_close_cb close_cb) {
+	if (setsockopt(handle->io_watcher.fd, SOL_SOCKET, SO_LINGER,
+		       &(struct linger){ 1, 0 }, sizeof(struct linger)) == -1)
+	{
+#if UV_VERSION_HEX >= UV_VERSION(1, 10, 0)
+		return (uv_translate_sys_error(errno));
+#else
+		return (-errno);
+#endif /* UV_VERSION_HEX >= UV_VERSION(1, 10, 0) */
+	}
+
+	uv_close((uv_handle_t *)handle, close_cb);
+	return (0);
+}
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 32, 0) */
+
+int
+isc_uv_udp_freebind(uv_udp_t *handle, const struct sockaddr *addr,
+		    unsigned int flags) {
+	int r;
+	uv_os_sock_t fd;
+
+	r = uv_fileno((const uv_handle_t *)handle, (uv_os_fd_t *)&fd);
+	if (r < 0) {
+		return (r);
+	}
+
+#if defined(WIN32)
+	REQUIRE(fd != INVALID_SOCKET);
+#endif
+
+	r = uv_udp_bind(handle, addr, flags);
+	if (r == UV_EADDRNOTAVAIL &&
+	    isc__nm_socket_freebind(fd, addr->sa_family) == ISC_R_SUCCESS)
+	{
+		/*
+		 * Retry binding with IP_FREEBIND (or equivalent option) if the
+		 * address is not available. This helps with IPv6 tentative
+		 * addresses which are reported by the route socket, although
+		 * named is not yet able to properly bind to them.
+		 */
+		r = uv_udp_bind(handle, addr, flags);
+	}
+
+	return (r);
+}
+
+static int
+isc__uv_tcp_bind_now(uv_tcp_t *handle, const struct sockaddr *addr,
+		     unsigned int flags) {
+	int r;
+	struct sockaddr_storage sname;
+	int snamelen = sizeof(sname);
+
+	r = uv_tcp_bind(handle, addr, flags);
+	if (r < 0) {
+		return (r);
+	}
+
+	/*
+	 * uv_tcp_bind() uses a delayed error, initially returning
+	 * success even if bind() fails. By calling uv_tcp_getsockname()
+	 * here we can find out whether the bind() call was successful.
+	 */
+	r = uv_tcp_getsockname(handle, (struct sockaddr *)&sname, &snamelen);
+	if (r < 0) {
+		return (r);
+	}
+
+	return (0);
+}
+
+int
+isc_uv_tcp_freebind(uv_tcp_t *handle, const struct sockaddr *addr,
+		    unsigned int flags) {
+	int r;
+	uv_os_sock_t fd;
+
+	r = uv_fileno((const uv_handle_t *)handle, (uv_os_fd_t *)&fd);
+	if (r < 0) {
+		return (r);
+	}
+
+	r = isc__uv_tcp_bind_now(handle, addr, flags);
+	if (r == UV_EADDRNOTAVAIL &&
+	    isc__nm_socket_freebind(fd, addr->sa_family) == ISC_R_SUCCESS)
+	{
+		/*
+		 * Retry binding with IP_FREEBIND (or equivalent option) if the
+		 * address is not available. This helps with IPv6 tentative
+		 * addresses which are reported by the route socket, although
+		 * named is not yet able to properly bind to them.
+		 */
+		r = isc__uv_tcp_bind_now(handle, addr, flags);
+	}
+
+	return (r);
+}
diff --git a/lib/isc/netmgr/uv-compat.h b/lib/isc/netmgr/uv-compat.h
new file mode 100644
index 0000000..3a10387
--- /dev/null
+++ b/lib/isc/netmgr/uv-compat.h
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#pragma once
+#include <uv.h>
+
+/*
+ * These functions were introduced in newer libuv, but we still
+ * want BIND9 compile on older ones so we emulate them.
+ * They're inline to avoid conflicts when running with a newer
+ * library version.
+ */
+
+#define UV_VERSION(major, minor, patch) ((major << 16) | (minor << 8) | (patch))
+
+/*
+ * Copied verbatim from libuv/src/version.c
+ */
+
+#define UV_STRINGIFY(v)	       UV_STRINGIFY_HELPER(v)
+#define UV_STRINGIFY_HELPER(v) #v
+
+#define UV_VERSION_STRING_BASE         \
+	UV_STRINGIFY(UV_VERSION_MAJOR) \
+	"." UV_STRINGIFY(UV_VERSION_MINOR) "." UV_STRINGIFY(UV_VERSION_PATCH)
+
+#if UV_VERSION_IS_RELEASE
+#define UV_VERSION_STRING UV_VERSION_STRING_BASE
+#else
+#define UV_VERSION_STRING UV_VERSION_STRING_BASE "-" UV_VERSION_SUFFIX
+#endif
+
+#if !defined(UV__ERR)
+#define UV__ERR(x) (-(x))
+#endif
+
+#if UV_VERSION_HEX < UV_VERSION(1, 19, 0)
+static inline void *
+uv_handle_get_data(const uv_handle_t *handle) {
+	return (handle->data);
+}
+
+static inline void
+uv_handle_set_data(uv_handle_t *handle, void *data) {
+	handle->data = data;
+}
+
+static inline void *
+uv_req_get_data(const uv_req_t *req) {
+	return (req->data);
+}
+
+static inline void
+uv_req_set_data(uv_req_t *req, void *data) {
+	req->data = data;
+}
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 19, 0) */
+
+#if UV_VERSION_HEX < UV_VERSION(1, 32, 0)
+int
+uv_tcp_close_reset(uv_tcp_t *handle, uv_close_cb close_cb);
+#endif
+
+#if UV_VERSION_HEX < UV_VERSION(1, 34, 0)
+#define uv_sleep(msec) usleep(msec * 1000)
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 34, 0) */
+
+#if UV_VERSION_HEX < UV_VERSION(1, 27, 0)
+int
+isc_uv_udp_connect(uv_udp_t *handle, const struct sockaddr *addr);
+/*%<
+ * Associate the UDP handle to a remote address and port, so every message sent
+ * by this handle is automatically sent to that destination.
+ *
+ * NOTE: This is just a limited shim for uv_udp_connect() as it requires the
+ * handle to be bound.
+ */
+#else /* UV_VERSION_HEX < UV_VERSION(1, 27, 0) */
+#define isc_uv_udp_connect uv_udp_connect
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 27, 0) */
+
+#if UV_VERSION_HEX < UV_VERSION(1, 12, 0)
+#include <stdlib.h>
+#include <string.h>
+
+static inline int
+uv_os_getenv(const char *name, char *buffer, size_t *size) {
+	size_t len;
+	char *buf = getenv(name);
+
+	if (buf == NULL) {
+		return (UV_ENOENT);
+	}
+
+	len = strlen(buf) + 1;
+	if (len > *size) {
+		*size = len;
+		return (UV_ENOBUFS);
+	}
+
+	*size = len;
+	memmove(buffer, buf, len);
+
+	return (0);
+}
+
+#define uv_os_setenv(name, value) setenv(name, value, 0)
+#endif /* UV_VERSION_HEX < UV_VERSION(1, 12, 0) */
+
+int
+isc_uv_udp_freebind(uv_udp_t *handle, const struct sockaddr *addr,
+		    unsigned int flags);
+
+int
+isc_uv_tcp_freebind(uv_tcp_t *handle, const struct sockaddr *addr,
+		    unsigned int flags);
diff --git a/lib/isc/netmgr/uverr2result.c b/lib/isc/netmgr/uverr2result.c
new file mode 100644
index 0000000..5ce953d
--- /dev/null
+++ b/lib/isc/netmgr/uverr2result.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <stdbool.h>
+#include <uv.h>
+
+#include <isc/result.h>
+#include <isc/strerr.h>
+#include <isc/string.h>
+#include <isc/util.h>
+
+#include "netmgr-int.h"
+
+/*%
+ * Convert a libuv error value into an isc_result_t.  The
+ * list of supported error values is not complete; new users
+ * of this function should add any expected errors that are
+ * not already there.
+ */
+isc_result_t
+isc___nm_uverr2result(int uverr, bool dolog, const char *file,
+		      unsigned int line, const char *func) {
+	switch (uverr) {
+	case 0:
+		return (ISC_R_SUCCESS);
+	case UV_ENOTDIR:
+	case UV_ELOOP:
+	case UV_EINVAL: /* XXX sometimes this is not for files */
+	case UV_ENAMETOOLONG:
+	case UV_EBADF:
+		return (ISC_R_INVALIDFILE);
+	case UV_ENOENT:
+		return (ISC_R_FILENOTFOUND);
+	case UV_EAGAIN:
+		return (ISC_R_NOCONN);
+	case UV_EACCES:
+	case UV_EPERM:
+		return (ISC_R_NOPERM);
+	case UV_EEXIST:
+		return (ISC_R_FILEEXISTS);
+	case UV_EIO:
+		return (ISC_R_IOERROR);
+	case UV_ENOMEM:
+		return (ISC_R_NOMEMORY);
+	case UV_ENFILE:
+	case UV_EMFILE:
+		return (ISC_R_TOOMANYOPENFILES);
+	case UV_ENOSPC:
+		return (ISC_R_DISCFULL);
+	case UV_EPIPE:
+	case UV_ECONNRESET:
+	case UV_ECONNABORTED:
+		return (ISC_R_CONNECTIONRESET);
+	case UV_ENOTCONN:
+		return (ISC_R_NOTCONNECTED);
+	case UV_ETIMEDOUT:
+		return (ISC_R_TIMEDOUT);
+	case UV_ENOBUFS:
+		return (ISC_R_NORESOURCES);
+	case UV_EAFNOSUPPORT:
+		return (ISC_R_FAMILYNOSUPPORT);
+	case UV_ENETDOWN:
+		return (ISC_R_NETDOWN);
+	case UV_EHOSTDOWN:
+		return (ISC_R_HOSTDOWN);
+	case UV_ENETUNREACH:
+		return (ISC_R_NETUNREACH);
+	case UV_EHOSTUNREACH:
+		return (ISC_R_HOSTUNREACH);
+	case UV_EADDRINUSE:
+		return (ISC_R_ADDRINUSE);
+	case UV_EADDRNOTAVAIL:
+		return (ISC_R_ADDRNOTAVAIL);
+	case UV_ECONNREFUSED:
+		return (ISC_R_CONNREFUSED);
+	case UV_ECANCELED:
+		return (ISC_R_CANCELED);
+	case UV_EOF:
+		return (ISC_R_EOF);
+	case UV_EMSGSIZE:
+		return (ISC_R_MAXSIZE);
+	case UV_ENOTSUP:
+		return (ISC_R_FAMILYNOSUPPORT);
+	default:
+		if (dolog) {
+			UNEXPECTED_ERROR(
+				file, line,
+				"unable to convert libuv "
+				"error code in %s to isc_result: %d: %s",
+				func, uverr, uv_strerror(uverr));
+		}
+		return (ISC_R_UNEXPECTED);
+	}
+}