bind/lib/isc/netmgr/tlsstream.c

/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * 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 <errno.h>
#include <libgen.h>
#include <unistd.h>
#include <uv.h>

#include <openssl/err.h>
#include <openssl/ssl.h>

#include <isc/atomic.h>
#include <isc/buffer.h>
#include <isc/condition.h>
#include <isc/log.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/netmgr.h>
#include <isc/once.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 "../openssl_shim.h"
#include "netmgr-int.h"
#include "uv-compat.h"

#define TLS_BUF_SIZE (UINT16_MAX)

static isc_result_t
tls_error_to_result(int tls_err) {
	switch (tls_err) {
	case SSL_ERROR_ZERO_RETURN:
		return (ISC_R_EOF);
	case SSL_ERROR_SSL:
		return (ISC_R_TLSERROR);
	default:
		return (ISC_R_UNEXPECTED);
	}
}

static void
tls_failed_read_cb(isc_nmsocket_t *sock, const isc_result_t result);

static void
tls_do_bio(isc_nmsocket_t *sock, isc_region_t *received_data,
	   isc__nm_uvreq_t *send_data, bool finish);

static void
tls_readcb(isc_nmhandle_t *handle, isc_result_t result, isc_region_t *region,
	   void *cbarg);

static void
tls_close_direct(isc_nmsocket_t *sock);

static void
async_tls_do_bio(isc_nmsocket_t *sock);

/*
 * The socket is closing, outerhandle has been detached, listener is
 * inactive, or the netmgr is closing: any operation on it should abort
 * with ISC_R_CANCELED.
 */
static bool
inactive(isc_nmsocket_t *sock) {
	return (!isc__nmsocket_active(sock) || atomic_load(&sock->closing) ||
		sock->outerhandle == NULL ||
		!isc__nmsocket_active(sock->outerhandle->sock) ||
		atomic_load(&sock->outerhandle->sock->closing) ||
		(sock->listener != NULL &&
		 !isc__nmsocket_active(sock->listener)) ||
		atomic_load(&sock->mgr->closing));
}

static void
update_result(isc_nmsocket_t *sock, const isc_result_t result) {
	if (!atomic_load(&sock->tlsstream.result_updated)) {
		atomic_store(&sock->tlsstream.result_updated, true);
		if (!sock->tlsstream.server) {
			LOCK(&sock->lock);
			sock->result = result;
			SIGNAL(&sock->cond);
			while (!atomic_load(&sock->active)) {
				WAIT(&sock->scond, &sock->lock);
			}
			UNLOCK(&sock->lock);
		} else {
			LOCK(&sock->lock);
			sock->result = result;
			UNLOCK(&sock->lock);
		}
	}
}

static void
tls_call_connect_cb(isc_nmsocket_t *sock, isc_nmhandle_t *handle,
		    const isc_result_t result) {
	if (sock->connect_cb == NULL) {
		return;
	}
	sock->connect_cb(handle, result, sock->connect_cbarg);
	if (result != ISC_R_SUCCESS) {
		isc__nmsocket_clearcb(handle->sock);
	}
}

static void
tls_senddone(isc_nmhandle_t *handle, isc_result_t eresult, void *cbarg) {
	isc_nmsocket_tls_send_req_t *send_req =
		(isc_nmsocket_tls_send_req_t *)cbarg;
	isc_nmsocket_t *tlssock = NULL;
	bool finish = send_req->finish;

	REQUIRE(VALID_NMHANDLE(handle));
	REQUIRE(VALID_NMSOCK(handle->sock));
	REQUIRE(VALID_NMSOCK(send_req->tlssock));

	tlssock = send_req->tlssock;
	send_req->tlssock = NULL;

	if (send_req->cb != NULL) {
		send_req->cb(send_req->handle, eresult, send_req->cbarg);
		isc_nmhandle_detach(&send_req->handle);
	}

	isc_mem_put(handle->sock->mgr->mctx, send_req->data.base,
		    send_req->data.length);
	isc_mem_put(handle->sock->mgr->mctx, send_req, sizeof(*send_req));
	tlssock->tlsstream.nsending--;

	if (finish && eresult == ISC_R_SUCCESS) {
		tlssock->tlsstream.reading = false;
		isc_nm_cancelread(handle);
	} else if (eresult == ISC_R_SUCCESS) {
		tls_do_bio(tlssock, NULL, NULL, false);
	} else if (eresult != ISC_R_SUCCESS &&
		   tlssock->tlsstream.state <= TLS_HANDSHAKE &&
		   !tlssock->tlsstream.server)
	{
		/*
		 * We are still waiting for the handshake to complete, but
		 * it isn't going to happen. Call the connect callback,
		 * passing the error code there.
		 *
		 * (Note: tls_failed_read_cb() calls the connect
		 * rather than the read callback in this case.
		 * XXX: clarify?)
		 */
		tls_failed_read_cb(tlssock, eresult);
	}

	isc__nmsocket_detach(&tlssock);
}

static void
tls_failed_read_cb(isc_nmsocket_t *sock, const isc_result_t result) {
	REQUIRE(VALID_NMSOCK(sock));

	if (!sock->tlsstream.server &&
	    (sock->tlsstream.state == TLS_INIT ||
	     sock->tlsstream.state == TLS_HANDSHAKE) &&
	    sock->connect_cb != NULL)
	{
		isc_nmhandle_t *handle = NULL;
		INSIST(sock->statichandle == NULL);
		handle = isc__nmhandle_get(sock, &sock->peer,
					   &sock->iface->addr);
		tls_call_connect_cb(sock, handle, result);
		isc__nmsocket_clearcb(sock);
		isc_nmhandle_detach(&handle);
	} else if (sock->recv_cb != NULL && sock->statichandle != NULL) {
		isc__nm_uvreq_t *req = NULL;
		INSIST(VALID_NMHANDLE(sock->statichandle));
		req = isc__nm_uvreq_get(sock->mgr, sock);
		req->cb.recv = sock->recv_cb;
		req->cbarg = sock->recv_cbarg;
		req->handle = NULL;
		isc_nmhandle_attach(sock->statichandle, &req->handle);
		isc__nmsocket_clearcb(sock);
		isc__nm_readcb(sock, req, result);
	}

	isc__nmsocket_prep_destroy(sock);
	isc__nmsocket_detach(&sock);
}

static void
async_tls_do_bio(isc_nmsocket_t *sock) {
	isc__netievent_tlsdobio_t *ievent =
		isc__nm_get_netievent_tlsdobio(sock->mgr, sock);
	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
			       (isc__netievent_t *)ievent);
}

static int
tls_send_outgoing(isc_nmsocket_t *sock, bool finish, isc_nmhandle_t *tlshandle,
		  isc_nm_cb_t cb, void *cbarg) {
	isc_nmsocket_tls_send_req_t *send_req = NULL;
	int pending;
	int rv;
	size_t len = 0;

	if (inactive(sock)) {
		if (cb != NULL) {
			INSIST(VALID_NMHANDLE(tlshandle));
			cb(tlshandle, ISC_R_CANCELED, cbarg);
		}
		return (0);
	}

	if (finish && (SSL_get_shutdown(sock->tlsstream.tls) &
		       SSL_SENT_SHUTDOWN) != SSL_SENT_SHUTDOWN)
	{
		(void)SSL_shutdown(sock->tlsstream.tls);
	}

	pending = BIO_pending(sock->tlsstream.bio_out);
	if (pending <= 0) {
		return (pending);
	}

	/* TODO Should we keep track of these requests in a list? */
	if (pending > TLS_BUF_SIZE) {
		pending = TLS_BUF_SIZE;
	}

	send_req = isc_mem_get(sock->mgr->mctx, sizeof(*send_req));
	*send_req = (isc_nmsocket_tls_send_req_t){
		.finish = finish,
		.data.base = isc_mem_get(sock->mgr->mctx, pending),
		.data.length = pending
	};

	isc__nmsocket_attach(sock, &send_req->tlssock);
	if (cb != NULL) {
		send_req->cb = cb;
		send_req->cbarg = cbarg;
		isc_nmhandle_attach(tlshandle, &send_req->handle);
	}

	rv = BIO_read_ex(sock->tlsstream.bio_out, send_req->data.base, pending,
			 &len);
	/* There's something pending, read must succeed */
	RUNTIME_CHECK(rv == 1);

	INSIST(VALID_NMHANDLE(sock->outerhandle));

	sock->tlsstream.nsending++;
	isc_nm_send(sock->outerhandle, &send_req->data, tls_senddone, send_req);

	return (pending);
}

static int
tls_process_outgoing(isc_nmsocket_t *sock, bool finish,
		     isc__nm_uvreq_t *send_data) {
	int pending;

	/* Data from TLS to network */
	if (send_data != NULL) {
		pending = tls_send_outgoing(sock, finish, send_data->handle,
					    send_data->cb.send,
					    send_data->cbarg);
	} else {
		bool received_shutdown =
			((SSL_get_shutdown(sock->tlsstream.tls) &
			  SSL_RECEIVED_SHUTDOWN) != 0);
		bool sent_shutdown = ((SSL_get_shutdown(sock->tlsstream.tls) &
				       SSL_SENT_SHUTDOWN) != 0);

		if (received_shutdown && !sent_shutdown) {
			finish = true;
			(void)SSL_shutdown(sock->tlsstream.tls);
		}
		pending = tls_send_outgoing(sock, finish, NULL, NULL, NULL);
	}

	return (pending);
}

static int
tls_try_handshake(isc_nmsocket_t *sock) {
	int rv = 0;
	isc_nmhandle_t *tlshandle = NULL;

	REQUIRE(sock->tlsstream.state == TLS_HANDSHAKE);

	if (SSL_is_init_finished(sock->tlsstream.tls) == 1) {
		return (0);
	}

	rv = SSL_do_handshake(sock->tlsstream.tls);
	if (rv == 1) {
		INSIST(SSL_is_init_finished(sock->tlsstream.tls) == 1);
		INSIST(sock->statichandle == NULL);
		tlshandle = isc__nmhandle_get(sock, &sock->peer,
					      &sock->iface->addr);
		if (sock->tlsstream.server) {
			sock->listener->accept_cb(tlshandle, ISC_R_SUCCESS,
						  sock->listener->accept_cbarg);
		} else {
			tls_call_connect_cb(sock, tlshandle, ISC_R_SUCCESS);
		}
		isc_nmhandle_detach(&tlshandle);
		sock->tlsstream.state = TLS_IO;
	}

	return (rv);
}

static void
tls_do_bio(isc_nmsocket_t *sock, isc_region_t *received_data,
	   isc__nm_uvreq_t *send_data, bool finish) {
	isc_result_t result = ISC_R_SUCCESS;
	int pending, tls_status = SSL_ERROR_NONE;
	int rv = 0;
	size_t len = 0;
	int saved_errno = 0;

	REQUIRE(VALID_NMSOCK(sock));
	REQUIRE(sock->tid == isc_nm_tid());

	/* We will resume read if TLS layer wants us to */
	if (sock->tlsstream.reading && sock->outerhandle) {
		REQUIRE(VALID_NMHANDLE(sock->outerhandle));
		isc_nm_pauseread(sock->outerhandle);
	}

	if (sock->tlsstream.state == TLS_INIT) {
		INSIST(received_data == NULL && send_data == NULL);
		if (sock->tlsstream.server) {
			SSL_set_accept_state(sock->tlsstream.tls);
		} else {
			SSL_set_connect_state(sock->tlsstream.tls);
		}
		sock->tlsstream.state = TLS_HANDSHAKE;
		rv = tls_try_handshake(sock);
		INSIST(SSL_is_init_finished(sock->tlsstream.tls) == 0);
	} else if (sock->tlsstream.state == TLS_CLOSED) {
		return;
	} else { /* initialised and doing I/O */
		if (received_data != NULL) {
			INSIST(send_data == NULL);
			rv = BIO_write_ex(sock->tlsstream.bio_in,
					  received_data->base,
					  received_data->length, &len);
			if (rv <= 0 || len != received_data->length) {
				result = ISC_R_TLSERROR;
				saved_errno = errno;
				goto error;
			}

			/*
			 * Only after doing the IO we can check whether SSL
			 * handshake is done.
			 */
			if (sock->tlsstream.state == TLS_HANDSHAKE) {
				rv = tls_try_handshake(sock);
			}
		} else if (send_data != NULL) {
			INSIST(received_data == NULL);
			INSIST(sock->tlsstream.state > TLS_HANDSHAKE);
			bool received_shutdown =
				((SSL_get_shutdown(sock->tlsstream.tls) &
				  SSL_RECEIVED_SHUTDOWN) != 0);
			rv = SSL_write_ex(sock->tlsstream.tls,
					  send_data->uvbuf.base,
					  send_data->uvbuf.len, &len);
			if (rv != 1 || len != send_data->uvbuf.len) {
				result = received_shutdown ? ISC_R_CANCELED
							   : ISC_R_TLSERROR;
				send_data->cb.send(send_data->handle, result,
						   send_data->cbarg);
				send_data = NULL;
				if (!received_shutdown) {
					isc__nmsocket_detach(&sock);
					return;
				}
			}
		}

		/* Decrypt and pass data from network to client */
		if (sock->tlsstream.state >= TLS_IO && sock->recv_cb != NULL &&
		    !atomic_load(&sock->readpaused))
		{
			uint8_t recv_buf[TLS_BUF_SIZE];
			INSIST(sock->tlsstream.state > TLS_HANDSHAKE);
			while ((rv = SSL_read_ex(sock->tlsstream.tls, recv_buf,
						 TLS_BUF_SIZE, &len)) == 1)
			{
				isc_region_t region;
				region = (isc_region_t){ .base = &recv_buf[0],
							 .length = len };

				sock->recv_cb(sock->statichandle, ISC_R_SUCCESS,
					      &region, sock->recv_cbarg);
			}
		}
	}
	tls_status = SSL_get_error(sock->tlsstream.tls, rv);
	saved_errno = errno;

	/* See "BUGS" section at:
	 * https://www.openssl.org/docs/man1.1.1/man3/SSL_get_error.html
	 *
	 * It is mentioned there that when TLS status equals
	 * SSL_ERROR_SYSCALL AND errno == 0 it means that underlying
	 * transport layer returned EOF prematurely.  However, we are
	 * managing the transport ourselves, so we should just resume
	 * reading from the TCP socket.
	 *
	 * It seems that this case has been handled properly on modern
	 * versions of OpenSSL. That being said, the situation goes in
	 * line with the manual: it is briefly mentioned there that
	 * SSL_ERROR_SYSCALL might be returned not only in a case of
	 * low-level errors (like system call failures).
	 */
	if (tls_status == SSL_ERROR_SYSCALL && saved_errno == 0 &&
	    received_data == NULL && send_data == NULL && finish == false)
	{
		tls_status = SSL_ERROR_WANT_READ;
	}

	pending = tls_process_outgoing(sock, finish, send_data);
	if (pending > 0) {
		/* We'll continue in tls_senddone */
		return;
	}

	switch (tls_status) {
	case SSL_ERROR_NONE:
	case SSL_ERROR_ZERO_RETURN:
		return;
	case SSL_ERROR_WANT_WRITE:
		if (sock->tlsstream.nsending == 0) {
			/*
			 * Launch tls_do_bio asynchronously. If we're sending
			 * already the send callback will call it.
			 */
			async_tls_do_bio(sock);
		}
		return;
	case SSL_ERROR_WANT_READ:
		if (sock->tlsstream.reading) {
			INSIST(VALID_NMHANDLE(sock->outerhandle));
			isc_nm_resumeread(sock->outerhandle);
		} else if (sock->tlsstream.state == TLS_HANDSHAKE) {
			sock->tlsstream.reading = true;
			isc_nm_read(sock->outerhandle, tls_readcb, sock);
		}
		return;
	default:
		result = tls_error_to_result(tls_status);
		break;
	}

error:
	isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL, ISC_LOGMODULE_NETMGR,
		      ISC_LOG_NOTICE,
		      "SSL error in BIO: %d %s (errno: %d). Arguments: "
		      "received_data: %p, "
		      "send_data: %p, finish: %s",
		      tls_status, isc_result_totext(result), saved_errno,
		      received_data, send_data, finish ? "true" : "false");
	tls_failed_read_cb(sock, result);
}

static void
tls_readcb(isc_nmhandle_t *handle, isc_result_t result, isc_region_t *region,
	   void *cbarg) {
	isc_nmsocket_t *tlssock = (isc_nmsocket_t *)cbarg;

	REQUIRE(VALID_NMSOCK(tlssock));
	REQUIRE(VALID_NMHANDLE(handle));
	REQUIRE(tlssock->tid == isc_nm_tid());

	if (result != ISC_R_SUCCESS) {
		tls_failed_read_cb(tlssock, result);
		return;
	}
	tls_do_bio(tlssock, region, NULL, false);
}

static isc_result_t
initialize_tls(isc_nmsocket_t *sock, bool server) {
	REQUIRE(sock->tid == isc_nm_tid());

	sock->tlsstream.bio_in = BIO_new(BIO_s_mem());
	if (sock->tlsstream.bio_in == NULL) {
		isc_tls_free(&sock->tlsstream.tls);
		return (ISC_R_TLSERROR);
	}
	sock->tlsstream.bio_out = BIO_new(BIO_s_mem());
	if (sock->tlsstream.bio_out == NULL) {
		BIO_free_all(sock->tlsstream.bio_in);
		sock->tlsstream.bio_in = NULL;
		isc_tls_free(&sock->tlsstream.tls);
		return (ISC_R_TLSERROR);
	}

	if (BIO_set_mem_eof_return(sock->tlsstream.bio_in, EOF) != 1 ||
	    BIO_set_mem_eof_return(sock->tlsstream.bio_out, EOF) != 1)
	{
		goto error;
	}

	SSL_set_bio(sock->tlsstream.tls, sock->tlsstream.bio_in,
		    sock->tlsstream.bio_out);
	sock->tlsstream.server = server;
	sock->tlsstream.nsending = 0;
	return (ISC_R_SUCCESS);
error:
	isc_tls_free(&sock->tlsstream.tls);
	sock->tlsstream.bio_out = sock->tlsstream.bio_in = NULL;
	return (ISC_R_TLSERROR);
}

static isc_result_t
tlslisten_acceptcb(isc_nmhandle_t *handle, isc_result_t result, void *cbarg) {
	isc_nmsocket_t *tlslistensock = (isc_nmsocket_t *)cbarg;
	isc_nmsocket_t *tlssock = NULL;

	/* If accept() was unsuccessful we can't do anything */
	if (result != ISC_R_SUCCESS) {
		return (result);
	}

	REQUIRE(VALID_NMHANDLE(handle));
	REQUIRE(VALID_NMSOCK(handle->sock));
	REQUIRE(VALID_NMSOCK(tlslistensock));
	REQUIRE(tlslistensock->type == isc_nm_tlslistener);

	/*
	 * We need to create a 'wrapper' tlssocket for this connection.
	 */
	tlssock = isc_mem_get(handle->sock->mgr->mctx, sizeof(*tlssock));
	isc__nmsocket_init(tlssock, handle->sock->mgr, isc_nm_tlssocket,
			   &tlslistensock->tlsstream.server_iface);

	/* We need to initialize SSL now to reference SSL_CTX properly */
	tlssock->tlsstream.ctx = tlslistensock->tlsstream.ctx;
	tlssock->tlsstream.tls = isc_tls_create(tlssock->tlsstream.ctx);
	if (tlssock->tlsstream.tls == NULL) {
		atomic_store(&tlssock->closed, true);
		isc__nmsocket_detach(&tlssock);
		return (ISC_R_TLSERROR);
	}

	tlssock->extrahandlesize = tlslistensock->extrahandlesize;
	isc__nmsocket_attach(tlslistensock, &tlssock->listener);
	isc_nmhandle_attach(handle, &tlssock->outerhandle);
	tlssock->peer = handle->sock->peer;
	tlssock->read_timeout = atomic_load(&handle->sock->mgr->init);
	tlssock->tid = isc_nm_tid();
	tlssock->tlsstream.state = TLS_INIT;

	tlssock->tlsstream.ctx = tlslistensock->tlsstream.ctx;

	result = initialize_tls(tlssock, true);
	RUNTIME_CHECK(result == ISC_R_SUCCESS);
	/* TODO: catch failure code, detach tlssock, and log the error */

	tls_do_bio(tlssock, NULL, NULL, false);
	return (result);
}

isc_result_t
isc_nm_listentls(isc_nm_t *mgr, isc_nmiface_t *iface,
		 isc_nm_accept_cb_t accept_cb, void *accept_cbarg,
		 size_t extrahandlesize, int backlog, isc_quota_t *quota,
		 SSL_CTX *sslctx, isc_nmsocket_t **sockp) {
	isc_result_t result;
	isc_nmsocket_t *tlssock = isc_mem_get(mgr->mctx, sizeof(*tlssock));
	isc_nmsocket_t *tsock = NULL;

	REQUIRE(VALID_NM(mgr));

	isc__nmsocket_init(tlssock, mgr, isc_nm_tlslistener, iface);
	tlssock->tlsstream.server_iface = *iface;
	ISC_LINK_INIT(&tlssock->tlsstream.server_iface.addr, link);
	tlssock->iface = &tlssock->tlsstream.server_iface;
	tlssock->result = ISC_R_DEFAULT;
	tlssock->accept_cb = accept_cb;
	tlssock->accept_cbarg = accept_cbarg;
	tlssock->extrahandlesize = extrahandlesize;
	tlssock->tlsstream.ctx = sslctx;
	tlssock->tlsstream.tls = NULL;

	/*
	 * tlssock will be a TLS 'wrapper' around an unencrypted stream.
	 * We set tlssock->outer to a socket listening for a TCP connection.
	 */
	result = isc_nm_listentcp(mgr, iface, tlslisten_acceptcb, tlssock,
				  extrahandlesize, backlog, quota,
				  &tlssock->outer);
	if (result != ISC_R_SUCCESS) {
		atomic_store(&tlssock->closed, true);
		isc__nmsocket_detach(&tlssock);
		return (result);
	}

	/* wait for listen result */
	isc__nmsocket_attach(tlssock->outer, &tsock);
	LOCK(&tlssock->outer->lock);
	while (tlssock->outer->rchildren != tlssock->outer->nchildren) {
		WAIT(&tlssock->outer->cond, &tlssock->outer->lock);
	}
	result = tlssock->outer->result;
	tlssock->result = result;
	atomic_store(&tlssock->active, true);
	INSIST(tlssock->outer->tlsstream.tlslistener == NULL);
	isc__nmsocket_attach(tlssock, &tlssock->outer->tlsstream.tlslistener);
	BROADCAST(&tlssock->outer->scond);
	UNLOCK(&tlssock->outer->lock);
	isc__nmsocket_detach(&tsock);
	INSIST(result != ISC_R_DEFAULT);

	if (result == ISC_R_SUCCESS) {
		atomic_store(&tlssock->listening, true);
		*sockp = tlssock;
	}

	return (result);
}

void
isc__nm_async_tlssend(isc__networker_t *worker, isc__netievent_t *ev0) {
	isc__netievent_tlssend_t *ievent = (isc__netievent_tlssend_t *)ev0;
	isc_nmsocket_t *sock = ievent->sock;
	isc__nm_uvreq_t *req = ievent->req;

	REQUIRE(VALID_UVREQ(req));
	REQUIRE(sock->tid == isc_nm_tid());

	UNUSED(worker);

	ievent->req = NULL;

	if (inactive(sock)) {
		req->cb.send(req->handle, ISC_R_CANCELED, req->cbarg);
		goto done;
	}

	tls_do_bio(sock, NULL, req, false);
done:
	isc_mem_free(sock->mgr->mctx, req->uvbuf.base);
	isc__nm_uvreq_put(&req, sock);
	return;
}

void
isc__nm_tls_send(isc_nmhandle_t *handle, const isc_region_t *region,
		 isc_nm_cb_t cb, void *cbarg) {
	isc__netievent_tlssend_t *ievent = NULL;
	isc__nm_uvreq_t *uvreq = NULL;
	isc_nmsocket_t *sock = NULL;

	REQUIRE(VALID_NMHANDLE(handle));
	REQUIRE(VALID_NMSOCK(handle->sock));

	sock = handle->sock;

	REQUIRE(sock->type == isc_nm_tlssocket);

	if (inactive(sock)) {
		cb(handle, ISC_R_CANCELED, cbarg);
		return;
	}

	uvreq = isc__nm_uvreq_get(sock->mgr, sock);
	isc_nmhandle_attach(handle, &uvreq->handle);
	uvreq->cb.send = cb;
	uvreq->cbarg = cbarg;

	uvreq->uvbuf.base = isc_mem_allocate(sock->mgr->mctx, region->length);
	memmove(uvreq->uvbuf.base, region->base, region->length);
	uvreq->uvbuf.len = region->length;

	/*
	 * We need to create an event and pass it using async channel
	 */
	ievent = isc__nm_get_netievent_tlssend(sock->mgr, sock, uvreq);
	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
			       (isc__netievent_t *)ievent);
}

void
isc__nm_async_tlsstartread(isc__networker_t *worker, isc__netievent_t *ev0) {
	isc__netievent_tlsstartread_t *ievent =
		(isc__netievent_tlsstartread_t *)ev0;
	isc_nmsocket_t *sock = ievent->sock;

	REQUIRE(sock->tid == isc_nm_tid());

	UNUSED(worker);

	tls_do_bio(sock, NULL, NULL, false);
}

void
isc__nm_tls_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
	isc__netievent_tlsstartread_t *ievent = NULL;
	isc_nmsocket_t *sock = NULL;

	REQUIRE(VALID_NMHANDLE(handle));

	sock = handle->sock;
	REQUIRE(VALID_NMSOCK(sock));
	REQUIRE(sock->statichandle == handle);
	REQUIRE(sock->tid == isc_nm_tid());
	REQUIRE(sock->recv_cb == NULL);

	if (inactive(sock)) {
		cb(handle, ISC_R_NOTCONNECTED, NULL, cbarg);
		return;
	}

	sock->recv_cb = cb;
	sock->recv_cbarg = cbarg;

	ievent = isc__nm_get_netievent_tlsstartread(sock->mgr, sock);
	isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
			       (isc__netievent_t *)ievent);
}

void
isc__nm_tls_pauseread(isc_nmhandle_t *handle) {
	REQUIRE(VALID_NMHANDLE(handle));
	REQUIRE(VALID_NMSOCK(handle->sock));

	if (atomic_compare_exchange_strong(&handle->sock->readpaused,
					   &(bool){ false }, true))
	{
		if (handle->sock->outerhandle != NULL) {
			isc_nm_pauseread(handle->sock->outerhandle);
		}
	}
}

void
isc__nm_tls_resumeread(isc_nmhandle_t *handle) {
	REQUIRE(VALID_NMHANDLE(handle));
	REQUIRE(VALID_NMSOCK(handle->sock));

	if (!atomic_compare_exchange_strong(&handle->sock->readpaused,
					    &(bool){ false }, false))
	{
		async_tls_do_bio(handle->sock);
	}
}

static void
tls_close_direct(isc_nmsocket_t *sock) {
	REQUIRE(VALID_NMSOCK(sock));
	REQUIRE(sock->tid == isc_nm_tid());
	/*
	 * At this point we're certain that there are no
	 * external references, we can close everything.
	 */
	if (sock->outerhandle != NULL) {
		isc_nm_pauseread(sock->outerhandle);
		isc__nmsocket_clearcb(sock->outerhandle->sock);
		isc_nmhandle_detach(&sock->outerhandle);
	}

	if (sock->listener != NULL) {
		isc__nmsocket_detach(&sock->listener);
	}

	/* further cleanup performed in isc__nm_tls_cleanup_data() */
	atomic_store(&sock->closed, true);
	sock->tlsstream.state = TLS_CLOSED;
}

void
isc__nm_tls_close(isc_nmsocket_t *sock) {
	isc__netievent_tlsclose_t *ievent = NULL;

	REQUIRE(VALID_NMSOCK(sock));
	REQUIRE(sock->type == isc_nm_tlssocket);

	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
					    true)) {
		return;
	}

	ievent = isc__nm_get_netievent_tlsclose(sock->mgr, sock);
	isc__nm_maybe_enqueue_ievent(&sock->mgr->workers[sock->tid],
				     (isc__netievent_t *)ievent);
}

void
isc__nm_async_tlsclose(isc__networker_t *worker, isc__netievent_t *ev0) {
	isc__netievent_tlsclose_t *ievent = (isc__netievent_tlsclose_t *)ev0;
	isc_nmsocket_t *sock = ievent->sock;

	REQUIRE(ievent->sock->tid == isc_nm_tid());

	UNUSED(worker);

	tls_close_direct(sock);
}

void
isc__nm_tls_stoplistening(isc_nmsocket_t *sock) {
	REQUIRE(VALID_NMSOCK(sock));
	REQUIRE(sock->type == isc_nm_tlslistener);

	atomic_store(&sock->listening, false);
	atomic_store(&sock->closed, true);
	sock->recv_cb = NULL;
	sock->recv_cbarg = NULL;
	if (sock->tlsstream.tls != NULL) {
		isc_tls_free(&sock->tlsstream.tls);
		sock->tlsstream.ctx = NULL;
	}

	if (sock->outer != NULL) {
		isc_nm_stoplistening(sock->outer);
		isc__nmsocket_detach(&sock->outer);
	}
}

void
isc_nm_tlsconnect(isc_nm_t *mgr, isc_nmiface_t *local, isc_nmiface_t *peer,
		  isc_nm_cb_t cb, void *cbarg, SSL_CTX *ctx,
		  unsigned int timeout, size_t extrahandlesize) {
	isc_nmsocket_t *nsock = NULL, *tsock = NULL;
	isc__netievent_tlsconnect_t *ievent = NULL;
#if defined(NETMGR_TRACE) && defined(NETMGR_TRACE_VERBOSE)
	fprintf(stderr, "TLS: isc_nm_tlsconnect(): in net thread: %s\n",
		isc__nm_in_netthread() ? "yes" : "no");
#endif /* NETMGR_TRACE */

	REQUIRE(VALID_NM(mgr));

	nsock = isc_mem_get(mgr->mctx, sizeof(*nsock));
	isc__nmsocket_init(nsock, mgr, isc_nm_tlssocket, local);
	nsock->tlsstream.local_iface = *local;
	ISC_LINK_INIT(&nsock->tlsstream.local_iface.addr, link);
	nsock->iface = &nsock->tlsstream.local_iface;
	nsock->extrahandlesize = extrahandlesize;
	nsock->result = ISC_R_DEFAULT;
	nsock->connect_cb = cb;
	nsock->connect_cbarg = cbarg;
	nsock->connect_timeout = timeout;
	nsock->tlsstream.ctx = ctx;

	ievent = isc__nm_get_netievent_tlsconnect(mgr, nsock);
	ievent->local = local->addr;
	ievent->peer = peer->addr;
	ievent->ctx = ctx;

	isc__nmsocket_attach(nsock, &tsock);
	if (isc__nm_in_netthread()) {
		atomic_store(&nsock->active, true);
		nsock->tid = isc_nm_tid();
		isc__nm_async_tlsconnect(&mgr->workers[nsock->tid],
					 (isc__netievent_t *)ievent);
		isc__nm_put_netievent_tlsconnect(mgr, ievent);
	} else {
		nsock->tid = isc_random_uniform(mgr->nworkers);
		isc__nm_enqueue_ievent(&mgr->workers[nsock->tid],
				       (isc__netievent_t *)ievent);
	}

	LOCK(&nsock->lock);
	while (nsock->result == ISC_R_DEFAULT) {
		WAIT(&nsock->cond, &nsock->lock);
	}
	atomic_store(&nsock->active, true);
	BROADCAST(&nsock->scond);
	UNLOCK(&nsock->lock);
	INSIST(VALID_NMSOCK(nsock));
	isc__nmsocket_detach(&tsock);
}

static void
tcp_connected(isc_nmhandle_t *handle, isc_result_t result, void *cbarg) {
	isc_nmsocket_t *tlssock = (isc_nmsocket_t *)cbarg;
	isc_nmhandle_t *tlshandle = NULL;

	REQUIRE(VALID_NMSOCK(tlssock));
	REQUIRE(VALID_NMHANDLE(handle));

	if (result != ISC_R_SUCCESS) {
		goto error;
	}

	result = initialize_tls(tlssock, false);
	if (result != ISC_R_SUCCESS) {
		goto error;
	}

	tlssock->peer = isc_nmhandle_peeraddr(handle);
	isc_nmhandle_attach(handle, &tlssock->outerhandle);

	tls_do_bio(tlssock, NULL, NULL, false);
	return;
error:
	tlshandle = isc__nmhandle_get(tlssock, NULL, NULL);
	atomic_store(&tlssock->closed, true);
	tls_call_connect_cb(tlssock, tlshandle, result);
	isc_nmhandle_detach(&tlshandle);
	isc__nmsocket_detach(&tlssock);
}

void
isc__nm_async_tlsconnect(isc__networker_t *worker, isc__netievent_t *ev0) {
	isc__netievent_tlsconnect_t *ievent =
		(isc__netievent_tlsconnect_t *)ev0;
	isc_nmsocket_t *tlssock = ievent->sock;
	isc_result_t result;
	isc_nmhandle_t *tlshandle = NULL;

	UNUSED(worker);

	if (isc__nm_closing(tlssock)) {
		result = ISC_R_CANCELED;
		goto error;
	}

	/*
	 * We need to initialize SSL now to reference SSL_CTX properly.
	 */
	tlssock->tlsstream.tls = isc_tls_create(tlssock->tlsstream.ctx);
	if (tlssock->tlsstream.tls == NULL) {
		result = ISC_R_TLSERROR;
		goto error;
	}

	tlssock->tid = isc_nm_tid();
	tlssock->tlsstream.state = TLS_INIT;

	isc_nm_tcpconnect(worker->mgr, (isc_nmiface_t *)&ievent->local,
			  (isc_nmiface_t *)&ievent->peer, tcp_connected,
			  tlssock, tlssock->connect_timeout, 0);

	update_result(tlssock, ISC_R_SUCCESS);
	return;

error:
	tlshandle = isc__nmhandle_get(tlssock, NULL, NULL);
	atomic_store(&tlssock->closed, true);
	tls_call_connect_cb(tlssock, tlshandle, result);
	update_result(tlssock, result);
	isc_nmhandle_detach(&tlshandle);
	isc__nmsocket_detach(&tlssock);
}

static void
tls_cancelread(isc_nmsocket_t *sock) {
	if (!inactive(sock) && sock->tlsstream.state == TLS_IO) {
		tls_do_bio(sock, NULL, NULL, true);
	} else if (sock->outerhandle != NULL) {
		sock->tlsstream.reading = false;
		isc_nm_cancelread(sock->outerhandle);
	}
}

void
isc__nm_tls_cancelread(isc_nmhandle_t *handle) {
	isc_nmsocket_t *sock = NULL;
	isc__netievent_tlscancel_t *ievent = NULL;

	REQUIRE(VALID_NMHANDLE(handle));

	sock = handle->sock;

	REQUIRE(sock->type == isc_nm_tlssocket);

	if (sock->tid == isc_nm_tid()) {
		tls_cancelread(sock);
	} else {
		ievent = isc__nm_get_netievent_tlscancel(sock->mgr, sock,
							 handle);
		isc__nm_enqueue_ievent(&sock->mgr->workers[sock->tid],
				       (isc__netievent_t *)ievent);
	}
}

void
isc__nm_async_tlscancel(isc__networker_t *worker, isc__netievent_t *ev0) {
	isc__netievent_tlscancel_t *ievent = (isc__netievent_tlscancel_t *)ev0;
	isc_nmsocket_t *sock = ievent->sock;

	REQUIRE(VALID_NMSOCK(sock));
	REQUIRE(worker->id == sock->tid);
	REQUIRE(sock->tid == isc_nm_tid());

	UNUSED(worker);
	tls_cancelread(sock);
}

void
isc__nm_async_tlsdobio(isc__networker_t *worker, isc__netievent_t *ev0) {
	isc__netievent_tlsdobio_t *ievent = (isc__netievent_tlsdobio_t *)ev0;

	UNUSED(worker);

	tls_do_bio(ievent->sock, NULL, NULL, false);
}

void
isc__nm_tls_cleanup_data(isc_nmsocket_t *sock) {
	if (sock->type == isc_nm_tcplistener &&
	    sock->tlsstream.tlslistener != NULL) {
		REQUIRE(VALID_NMSOCK(sock->tlsstream.tlslistener));
		isc__nmsocket_detach(&sock->tlsstream.tlslistener);
	} else if (sock->type == isc_nm_tlssocket) {
		if (sock->tlsstream.tls != NULL) {
			isc_tls_free(&sock->tlsstream.tls);
			/* These are destroyed when we free SSL */
			sock->tlsstream.ctx = NULL;
			sock->tlsstream.bio_out = NULL;
			sock->tlsstream.bio_in = NULL;
		}
	}
}

void
isc__nm_tls_cleartimeout(isc_nmhandle_t *handle) {
	isc_nmsocket_t *sock = NULL;

	REQUIRE(VALID_NMHANDLE(handle));
	REQUIRE(VALID_NMSOCK(handle->sock));
	REQUIRE(handle->sock->type == isc_nm_tlssocket);

	sock = handle->sock;
	if (sock->outerhandle != NULL) {
		INSIST(VALID_NMHANDLE(sock->outerhandle));
		isc_nmhandle_cleartimeout(sock->outerhandle);
	}
}

void
isc__nm_tls_settimeout(isc_nmhandle_t *handle, uint32_t timeout) {
	isc_nmsocket_t *sock = NULL;

	REQUIRE(VALID_NMHANDLE(handle));
	REQUIRE(VALID_NMSOCK(handle->sock));
	REQUIRE(handle->sock->type == isc_nm_tlssocket);

	sock = handle->sock;
	if (sock->outerhandle != NULL) {
		INSIST(VALID_NMHANDLE(sock->outerhandle));
		isc_nmhandle_settimeout(sock->outerhandle, timeout);
	}
}