Adding upstream version 1:9.18.19.upstream/1%9.18.19upstream

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

1 files changed, 3093 insertions, 0 deletions

diff --git a/lib/ns/client.c b/lib/ns/client.c
new file mode 100644
index 0000000..5ed64fd
--- /dev/null
+++ b/lib/ns/client.c
@@ -0,0 +1,3093 @@
+/*
+ * 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 <limits.h>
+#include <stdbool.h>
+
+#include <isc/aes.h>
+#include <isc/atomic.h>
+#include <isc/formatcheck.h>
+#include <isc/fuzz.h>
+#include <isc/hmac.h>
+#include <isc/log.h>
+#include <isc/mutex.h>
+#include <isc/nonce.h>
+#include <isc/once.h>
+#include <isc/print.h>
+#include <isc/random.h>
+#include <isc/safe.h>
+#include <isc/serial.h>
+#include <isc/siphash.h>
+#include <isc/stats.h>
+#include <isc/stdio.h>
+#include <isc/string.h>
+#include <isc/task.h>
+#include <isc/thread.h>
+#include <isc/timer.h>
+#include <isc/util.h>
+
+#include <dns/adb.h>
+#include <dns/badcache.h>
+#include <dns/cache.h>
+#include <dns/db.h>
+#include <dns/dispatch.h>
+#include <dns/dnstap.h>
+#include <dns/edns.h>
+#include <dns/events.h>
+#include <dns/message.h>
+#include <dns/peer.h>
+#include <dns/rcode.h>
+#include <dns/rdata.h>
+#include <dns/rdataclass.h>
+#include <dns/rdatalist.h>
+#include <dns/rdataset.h>
+#include <dns/resolver.h>
+#include <dns/result.h>
+#include <dns/stats.h>
+#include <dns/tsig.h>
+#include <dns/view.h>
+#include <dns/zone.h>
+
+#include <ns/client.h>
+#include <ns/interfacemgr.h>
+#include <ns/log.h>
+#include <ns/notify.h>
+#include <ns/server.h>
+#include <ns/stats.h>
+#include <ns/update.h>
+
+/***
+ *** Client
+ ***/
+
+/*! \file
+ * Client Routines
+ *
+ * Important note!
+ *
+ * All client state changes, other than that from idle to listening, occur
+ * as a result of events.  This guarantees serialization and avoids the
+ * need for locking.
+ *
+ * If a routine is ever created that allows someone other than the client's
+ * task to change the client, then the client will have to be locked.
+ */
+
+#ifdef NS_CLIENT_TRACE
+#define CTRACE(m)                                                         \
+	ns_client_log(client, NS_LOGCATEGORY_CLIENT, NS_LOGMODULE_CLIENT, \
+		      ISC_LOG_DEBUG(3), "%s", (m))
+#define MTRACE(m)                                                          \
+	isc_log_write(ns_lctx, NS_LOGCATEGORY_CLIENT, NS_LOGMODULE_CLIENT, \
+		      ISC_LOG_DEBUG(3), "clientmgr @%p: %s", manager, (m))
+#else /* ifdef NS_CLIENT_TRACE */
+#define CTRACE(m) ((void)(m))
+#define MTRACE(m) ((void)(m))
+#endif /* ifdef NS_CLIENT_TRACE */
+
+#define TCP_CLIENT(c) (((c)->attributes & NS_CLIENTATTR_TCP) != 0)
+
+#define COOKIE_SIZE 24U /* 8 + 4 + 4 + 8 */
+#define ECS_SIZE    20U /* 2 + 1 + 1 + [0..16] */
+
+#define WANTNSID(x)	(((x)->attributes & NS_CLIENTATTR_WANTNSID) != 0)
+#define WANTEXPIRE(x)	(((x)->attributes & NS_CLIENTATTR_WANTEXPIRE) != 0)
+#define WANTPAD(x)	(((x)->attributes & NS_CLIENTATTR_WANTPAD) != 0)
+#define USEKEEPALIVE(x) (((x)->attributes & NS_CLIENTATTR_USEKEEPALIVE) != 0)
+
+#define MANAGER_MAGIC	 ISC_MAGIC('N', 'S', 'C', 'm')
+#define VALID_MANAGER(m) ISC_MAGIC_VALID(m, MANAGER_MAGIC)
+
+/*
+ * Enable ns_client_dropport() by default.
+ */
+#ifndef NS_CLIENT_DROPPORT
+#define NS_CLIENT_DROPPORT 1
+#endif /* ifndef NS_CLIENT_DROPPORT */
+
+atomic_uint_fast64_t ns_client_requests = 0;
+
+static void
+clientmgr_attach(ns_clientmgr_t *source, ns_clientmgr_t **targetp);
+static void
+clientmgr_destroy(ns_clientmgr_t *manager);
+static void
+ns_client_endrequest(ns_client_t *client);
+static void
+ns_client_dumpmessage(ns_client_t *client, const char *reason);
+static void
+compute_cookie(ns_client_t *client, uint32_t when, uint32_t nonce,
+	       const unsigned char *secret, isc_buffer_t *buf);
+
+void
+ns_client_recursing(ns_client_t *client) {
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(client->state == NS_CLIENTSTATE_WORKING);
+
+	LOCK(&client->manager->reclock);
+	client->state = NS_CLIENTSTATE_RECURSING;
+	ISC_LIST_APPEND(client->manager->recursing, client, rlink);
+	UNLOCK(&client->manager->reclock);
+}
+
+void
+ns_client_killoldestquery(ns_client_t *client) {
+	ns_client_t *oldest;
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	LOCK(&client->manager->reclock);
+	oldest = ISC_LIST_HEAD(client->manager->recursing);
+	if (oldest != NULL) {
+		ISC_LIST_UNLINK(client->manager->recursing, oldest, rlink);
+		ns_query_cancel(oldest);
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_reclimitdropped);
+	}
+	UNLOCK(&client->manager->reclock);
+}
+
+void
+ns_client_settimeout(ns_client_t *client, unsigned int seconds) {
+	UNUSED(client);
+	UNUSED(seconds);
+	/* XXXWPK TODO use netmgr to set timeout */
+}
+
+static void
+client_extendederror_reset(ns_client_t *client) {
+	if (client->ede == NULL) {
+		return;
+	}
+	isc_mem_put(client->mctx, client->ede->value, client->ede->length);
+	isc_mem_put(client->mctx, client->ede, sizeof(dns_ednsopt_t));
+	client->ede = NULL;
+}
+
+void
+ns_client_extendederror(ns_client_t *client, uint16_t code, const char *text) {
+	unsigned char ede[DNS_EDE_EXTRATEXT_LEN + 2];
+	isc_buffer_t buf;
+	uint16_t len = sizeof(uint16_t);
+
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	if (client->ede != NULL) {
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+			      "already have ede, ignoring %u %s", code,
+			      text == NULL ? "(null)" : text);
+		return;
+	}
+
+	ns_client_log(client, NS_LOGCATEGORY_CLIENT, NS_LOGMODULE_CLIENT,
+		      ISC_LOG_DEBUG(1), "set ede: info-code %u extra-text %s",
+		      code, text == NULL ? "(null)" : text);
+
+	isc_buffer_init(&buf, ede, sizeof(ede));
+	isc_buffer_putuint16(&buf, code);
+	if (text != NULL && strlen(text) > 0) {
+		if (strlen(text) < DNS_EDE_EXTRATEXT_LEN) {
+			isc_buffer_putstr(&buf, text);
+			len += (uint16_t)(strlen(text));
+		} else {
+			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_WARNING,
+				      "ede extra-text too long, ignoring");
+		}
+	}
+
+	client->ede = isc_mem_get(client->mctx, sizeof(dns_ednsopt_t));
+	client->ede->code = DNS_OPT_EDE;
+	client->ede->length = len;
+	client->ede->value = isc_mem_get(client->mctx, len);
+	memmove(client->ede->value, ede, len);
+};
+
+static void
+ns_client_endrequest(ns_client_t *client) {
+	INSIST(client->nupdates == 0);
+	INSIST(client->state == NS_CLIENTSTATE_WORKING ||
+	       client->state == NS_CLIENTSTATE_RECURSING);
+
+	CTRACE("endrequest");
+
+	if (client->state == NS_CLIENTSTATE_RECURSING) {
+		LOCK(&client->manager->reclock);
+		if (ISC_LINK_LINKED(client, rlink)) {
+			ISC_LIST_UNLINK(client->manager->recursing, client,
+					rlink);
+		}
+		UNLOCK(&client->manager->reclock);
+	}
+
+	if (client->cleanup != NULL) {
+		(client->cleanup)(client);
+		client->cleanup = NULL;
+	}
+
+	if (client->view != NULL) {
+#ifdef ENABLE_AFL
+		if (client->sctx->fuzztype == isc_fuzz_resolver) {
+			dns_cache_clean(client->view->cache, INT_MAX);
+			dns_adb_flush(client->view->adb);
+		}
+#endif /* ifdef ENABLE_AFL */
+		dns_view_detach(&client->view);
+	}
+	if (client->opt != NULL) {
+		INSIST(dns_rdataset_isassociated(client->opt));
+		dns_rdataset_disassociate(client->opt);
+		dns_message_puttemprdataset(client->message, &client->opt);
+	}
+
+	client_extendederror_reset(client);
+	client->signer = NULL;
+	client->udpsize = 512;
+	client->extflags = 0;
+	client->ednsversion = -1;
+	client->additionaldepth = 0;
+	dns_ecs_init(&client->ecs);
+	dns_message_reset(client->message, DNS_MESSAGE_INTENTPARSE);
+
+	/*
+	 * Clean up from recursion - normally this would be done in
+	 * fetch_callback(), but if we're shutting down and canceling then
+	 * it might not have happened.
+	 */
+	if (client->recursionquota != NULL) {
+		isc_quota_detach(&client->recursionquota);
+		ns_stats_decrement(client->sctx->nsstats,
+				   ns_statscounter_recursclients);
+	}
+
+	/*
+	 * Clear all client attributes that are specific to the request
+	 */
+	client->attributes = 0;
+#ifdef ENABLE_AFL
+	if (client->sctx->fuzznotify != NULL &&
+	    (client->sctx->fuzztype == isc_fuzz_client ||
+	     client->sctx->fuzztype == isc_fuzz_tcpclient ||
+	     client->sctx->fuzztype == isc_fuzz_resolver))
+	{
+		client->sctx->fuzznotify();
+	}
+#endif /* ENABLE_AFL */
+}
+
+void
+ns_client_drop(ns_client_t *client, isc_result_t result) {
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(client->state == NS_CLIENTSTATE_WORKING ||
+		client->state == NS_CLIENTSTATE_RECURSING);
+
+	CTRACE("drop");
+	if (result != ISC_R_SUCCESS) {
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "request failed: %s", isc_result_totext(result));
+	}
+}
+
+static void
+client_senddone(isc_nmhandle_t *handle, isc_result_t result, void *cbarg) {
+	ns_client_t *client = cbarg;
+
+	REQUIRE(client->sendhandle == handle);
+
+	CTRACE("senddone");
+
+	/*
+	 * Set sendhandle to NULL, but don't detach it immediately, in
+	 * case we need to retry the send. If we do resend, then
+	 * sendhandle will be reattached. Whether or not we resend,
+	 * we will then detach the handle from *this* send by detaching
+	 * 'handle' directly below.
+	 */
+	client->sendhandle = NULL;
+
+	if (result != ISC_R_SUCCESS) {
+		if (!TCP_CLIENT(client) && result == ISC_R_MAXSIZE) {
+			ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+				      "send exceeded maximum size: truncating");
+			client->query.attributes &= ~NS_QUERYATTR_ANSWERED;
+			client->rcode_override = dns_rcode_noerror;
+			ns_client_error(client, ISC_R_MAXSIZE);
+		} else {
+			ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+				      "send failed: %s",
+				      isc_result_totext(result));
+		}
+	}
+
+	isc_nmhandle_detach(&handle);
+}
+
+static void
+client_allocsendbuf(ns_client_t *client, isc_buffer_t *buffer,
+		    unsigned char **datap) {
+	unsigned char *data;
+	uint32_t bufsize;
+
+	REQUIRE(datap != NULL);
+
+	if (TCP_CLIENT(client)) {
+		INSIST(client->tcpbuf == NULL);
+		client->tcpbuf = isc_mem_get(client->manager->send_mctx,
+					     NS_CLIENT_TCP_BUFFER_SIZE);
+		client->tcpbuf_size = NS_CLIENT_TCP_BUFFER_SIZE;
+		data = client->tcpbuf;
+		isc_buffer_init(buffer, data, NS_CLIENT_TCP_BUFFER_SIZE);
+	} else {
+		data = client->sendbuf;
+		if ((client->attributes & NS_CLIENTATTR_HAVECOOKIE) == 0) {
+			if (client->view != NULL) {
+				bufsize = client->view->nocookieudp;
+			} else {
+				bufsize = 512;
+			}
+		} else {
+			bufsize = client->udpsize;
+		}
+		if (bufsize > client->udpsize) {
+			bufsize = client->udpsize;
+		}
+		if (bufsize > NS_CLIENT_SEND_BUFFER_SIZE) {
+			bufsize = NS_CLIENT_SEND_BUFFER_SIZE;
+		}
+		isc_buffer_init(buffer, data, bufsize);
+	}
+	*datap = data;
+}
+
+static void
+client_sendpkg(ns_client_t *client, isc_buffer_t *buffer) {
+	isc_result_t result;
+	isc_region_t r;
+	dns_ttl_t min_ttl = 0;
+
+	REQUIRE(client->sendhandle == NULL);
+
+	if (isc_buffer_base(buffer) == client->tcpbuf) {
+		size_t used = isc_buffer_usedlength(buffer);
+		client->tcpbuf = isc_mem_reget(client->manager->send_mctx,
+					       client->tcpbuf,
+					       client->tcpbuf_size, used);
+		client->tcpbuf_size = used;
+		r.base = client->tcpbuf;
+		r.length = used;
+	} else {
+		isc_buffer_usedregion(buffer, &r);
+	}
+	isc_nmhandle_attach(client->handle, &client->sendhandle);
+
+	if (isc_nm_is_http_handle(client->handle)) {
+		result = dns_message_response_minttl(client->message, &min_ttl);
+		if (result == ISC_R_SUCCESS) {
+			isc_nm_set_maxage(client->handle, min_ttl);
+		}
+	}
+	isc_nm_send(client->handle, &r, client_senddone, client);
+}
+
+void
+ns_client_sendraw(ns_client_t *client, dns_message_t *message) {
+	isc_result_t result;
+	unsigned char *data = NULL;
+	isc_buffer_t buffer;
+	isc_region_t r;
+	isc_region_t *mr = NULL;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	CTRACE("sendraw");
+
+	mr = dns_message_getrawmessage(message);
+	if (mr == NULL) {
+		result = ISC_R_UNEXPECTEDEND;
+		goto done;
+	}
+
+	client_allocsendbuf(client, &buffer, &data);
+
+	if (mr->length > isc_buffer_length(&buffer)) {
+		result = ISC_R_NOSPACE;
+		goto done;
+	}
+
+	/*
+	 * Copy message to buffer and fixup id.
+	 */
+	isc_buffer_availableregion(&buffer, &r);
+	result = isc_buffer_copyregion(&buffer, mr);
+	if (result != ISC_R_SUCCESS) {
+		goto done;
+	}
+	r.base[0] = (client->message->id >> 8) & 0xff;
+	r.base[1] = client->message->id & 0xff;
+
+#ifdef HAVE_DNSTAP
+	if (client->view != NULL) {
+		bool tcp = TCP_CLIENT(client);
+		dns_dtmsgtype_t dtmsgtype;
+		if (client->message->opcode == dns_opcode_update) {
+			dtmsgtype = DNS_DTTYPE_UR;
+		} else if ((client->message->flags & DNS_MESSAGEFLAG_RD) != 0) {
+			dtmsgtype = DNS_DTTYPE_CR;
+		} else {
+			dtmsgtype = DNS_DTTYPE_AR;
+		}
+		dns_dt_send(client->view, dtmsgtype, &client->peeraddr,
+			    &client->destsockaddr, tcp, NULL,
+			    &client->requesttime, NULL, &buffer);
+	}
+#endif
+
+	client_sendpkg(client, &buffer);
+
+	return;
+done:
+	if (client->tcpbuf != NULL) {
+		isc_mem_put(client->manager->send_mctx, client->tcpbuf,
+			    client->tcpbuf_size);
+	}
+
+	ns_client_drop(client, result);
+}
+
+void
+ns_client_send(ns_client_t *client) {
+	isc_result_t result;
+	unsigned char *data = NULL;
+	isc_buffer_t buffer = { .magic = 0 };
+	isc_region_t r;
+	dns_compress_t cctx;
+	bool cleanup_cctx = false;
+	unsigned int render_opts;
+	unsigned int preferred_glue;
+	bool opt_included = false;
+	size_t respsize;
+	dns_aclenv_t *env = NULL;
+#ifdef HAVE_DNSTAP
+	unsigned char zone[DNS_NAME_MAXWIRE];
+	dns_dtmsgtype_t dtmsgtype;
+	isc_region_t zr;
+#endif /* HAVE_DNSTAP */
+
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	if ((client->query.attributes & NS_QUERYATTR_ANSWERED) != 0) {
+		return;
+	}
+
+	/*
+	 * XXXWPK TODO
+	 * Delay the response according to the -T delay option
+	 */
+
+	env = client->manager->aclenv;
+
+	CTRACE("send");
+
+	if (client->message->opcode == dns_opcode_query &&
+	    (client->attributes & NS_CLIENTATTR_RA) != 0)
+	{
+		client->message->flags |= DNS_MESSAGEFLAG_RA;
+	}
+
+	if ((client->attributes & NS_CLIENTATTR_WANTDNSSEC) != 0) {
+		render_opts = 0;
+	} else {
+		render_opts = DNS_MESSAGERENDER_OMITDNSSEC;
+	}
+
+	preferred_glue = 0;
+	if (client->view != NULL) {
+		if (client->view->preferred_glue == dns_rdatatype_a) {
+			preferred_glue = DNS_MESSAGERENDER_PREFER_A;
+		} else if (client->view->preferred_glue == dns_rdatatype_aaaa) {
+			preferred_glue = DNS_MESSAGERENDER_PREFER_AAAA;
+		}
+	}
+	if (preferred_glue == 0) {
+		if (isc_sockaddr_pf(&client->peeraddr) == AF_INET) {
+			preferred_glue = DNS_MESSAGERENDER_PREFER_A;
+		} else {
+			preferred_glue = DNS_MESSAGERENDER_PREFER_AAAA;
+		}
+	}
+
+	/*
+	 * Create an OPT for our reply.
+	 */
+	if ((client->attributes & NS_CLIENTATTR_WANTOPT) != 0) {
+		result = ns_client_addopt(client, client->message,
+					  &client->opt);
+		if (result != ISC_R_SUCCESS) {
+			goto cleanup;
+		}
+	}
+
+	client_allocsendbuf(client, &buffer, &data);
+
+	result = dns_compress_init(&cctx, -1, client->mctx);
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+	if (client->peeraddr_valid && client->view != NULL) {
+		isc_netaddr_t netaddr;
+		dns_name_t *name = NULL;
+
+		isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+		if (client->message->tsigkey != NULL) {
+			name = &client->message->tsigkey->name;
+		}
+
+		if (client->view->nocasecompress == NULL ||
+		    !dns_acl_allowed(&netaddr, name,
+				     client->view->nocasecompress, env))
+		{
+			dns_compress_setsensitive(&cctx, true);
+		}
+
+		if (!client->view->msgcompression) {
+			dns_compress_disable(&cctx);
+		}
+	}
+	cleanup_cctx = true;
+
+	result = dns_message_renderbegin(client->message, &cctx, &buffer);
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+
+	if (client->opt != NULL) {
+		result = dns_message_setopt(client->message, client->opt);
+		opt_included = true;
+		client->opt = NULL;
+		if (result != ISC_R_SUCCESS) {
+			goto cleanup;
+		}
+	}
+	result = dns_message_rendersection(client->message,
+					   DNS_SECTION_QUESTION, 0);
+	if (result == ISC_R_NOSPACE) {
+		client->message->flags |= DNS_MESSAGEFLAG_TC;
+		goto renderend;
+	}
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+	/*
+	 * Stop after the question if TC was set for rate limiting.
+	 */
+	if ((client->message->flags & DNS_MESSAGEFLAG_TC) != 0) {
+		goto renderend;
+	}
+	result = dns_message_rendersection(client->message, DNS_SECTION_ANSWER,
+					   DNS_MESSAGERENDER_PARTIAL |
+						   render_opts);
+	if (result == ISC_R_NOSPACE) {
+		client->message->flags |= DNS_MESSAGEFLAG_TC;
+		goto renderend;
+	}
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+	result = dns_message_rendersection(
+		client->message, DNS_SECTION_AUTHORITY,
+		DNS_MESSAGERENDER_PARTIAL | render_opts);
+	if (result == ISC_R_NOSPACE) {
+		client->message->flags |= DNS_MESSAGEFLAG_TC;
+		goto renderend;
+	}
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+	result = dns_message_rendersection(client->message,
+					   DNS_SECTION_ADDITIONAL,
+					   preferred_glue | render_opts);
+	if (result != ISC_R_SUCCESS && result != ISC_R_NOSPACE) {
+		goto cleanup;
+	}
+renderend:
+	result = dns_message_renderend(client->message);
+	if (result != ISC_R_SUCCESS) {
+		goto cleanup;
+	}
+
+#ifdef HAVE_DNSTAP
+	memset(&zr, 0, sizeof(zr));
+	if (((client->message->flags & DNS_MESSAGEFLAG_AA) != 0) &&
+	    (client->query.authzone != NULL))
+	{
+		isc_result_t eresult;
+		isc_buffer_t b;
+		dns_name_t *zo = dns_zone_getorigin(client->query.authzone);
+
+		isc_buffer_init(&b, zone, sizeof(zone));
+		dns_compress_setmethods(&cctx, DNS_COMPRESS_NONE);
+		eresult = dns_name_towire(zo, &cctx, &b);
+		if (eresult == ISC_R_SUCCESS) {
+			isc_buffer_usedregion(&b, &zr);
+		}
+	}
+
+	if (client->message->opcode == dns_opcode_update) {
+		dtmsgtype = DNS_DTTYPE_UR;
+	} else if ((client->message->flags & DNS_MESSAGEFLAG_RD) != 0) {
+		dtmsgtype = DNS_DTTYPE_CR;
+	} else {
+		dtmsgtype = DNS_DTTYPE_AR;
+	}
+#endif /* HAVE_DNSTAP */
+
+	if (cleanup_cctx) {
+		dns_compress_invalidate(&cctx);
+	}
+
+	if (client->sendcb != NULL) {
+		client->sendcb(&buffer);
+	} else if (TCP_CLIENT(client)) {
+		isc_buffer_usedregion(&buffer, &r);
+#ifdef HAVE_DNSTAP
+		if (client->view != NULL) {
+			dns_dt_send(client->view, dtmsgtype, &client->peeraddr,
+				    &client->destsockaddr, true, &zr,
+				    &client->requesttime, NULL, &buffer);
+		}
+#endif /* HAVE_DNSTAP */
+
+		respsize = isc_buffer_usedlength(&buffer);
+
+		client_sendpkg(client, &buffer);
+
+		switch (isc_sockaddr_pf(&client->peeraddr)) {
+		case AF_INET:
+			isc_stats_increment(client->sctx->tcpoutstats4,
+					    ISC_MIN((int)respsize / 16, 256));
+			break;
+		case AF_INET6:
+			isc_stats_increment(client->sctx->tcpoutstats6,
+					    ISC_MIN((int)respsize / 16, 256));
+			break;
+		default:
+			UNREACHABLE();
+		}
+	} else {
+#ifdef HAVE_DNSTAP
+		/*
+		 * Log dnstap data first, because client_sendpkg() may
+		 * leave client->view set to NULL.
+		 */
+		if (client->view != NULL) {
+			dns_dt_send(client->view, dtmsgtype, &client->peeraddr,
+				    &client->destsockaddr, false, &zr,
+				    &client->requesttime, NULL, &buffer);
+		}
+#endif /* HAVE_DNSTAP */
+
+		respsize = isc_buffer_usedlength(&buffer);
+
+		client_sendpkg(client, &buffer);
+
+		switch (isc_sockaddr_pf(&client->peeraddr)) {
+		case AF_INET:
+			isc_stats_increment(client->sctx->udpoutstats4,
+					    ISC_MIN((int)respsize / 16, 256));
+			break;
+		case AF_INET6:
+			isc_stats_increment(client->sctx->udpoutstats6,
+					    ISC_MIN((int)respsize / 16, 256));
+			break;
+		default:
+			UNREACHABLE();
+		}
+	}
+
+	/* update statistics (XXXJT: is it okay to access message->xxxkey?) */
+	ns_stats_increment(client->sctx->nsstats, ns_statscounter_response);
+
+	dns_rcodestats_increment(client->sctx->rcodestats,
+				 client->message->rcode);
+	if (opt_included) {
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_edns0out);
+	}
+	if (client->message->tsigkey != NULL) {
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_tsigout);
+	}
+	if (client->message->sig0key != NULL) {
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_sig0out);
+	}
+	if ((client->message->flags & DNS_MESSAGEFLAG_TC) != 0) {
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_truncatedresp);
+	}
+
+	client->query.attributes |= NS_QUERYATTR_ANSWERED;
+
+	return;
+
+cleanup:
+	if (client->tcpbuf != NULL) {
+		isc_mem_put(client->manager->send_mctx, client->tcpbuf,
+			    client->tcpbuf_size);
+	}
+
+	if (cleanup_cctx) {
+		dns_compress_invalidate(&cctx);
+	}
+}
+
+#if NS_CLIENT_DROPPORT
+#define DROPPORT_NO	  0
+#define DROPPORT_REQUEST  1
+#define DROPPORT_RESPONSE 2
+/*%
+ * ns_client_dropport determines if certain requests / responses
+ * should be dropped based on the port number.
+ *
+ * Returns:
+ * \li	0:	Don't drop.
+ * \li	1:	Drop request.
+ * \li	2:	Drop (error) response.
+ */
+static int
+ns_client_dropport(in_port_t port) {
+	switch (port) {
+	case 7:	 /* echo */
+	case 13: /* daytime */
+	case 19: /* chargen */
+	case 37: /* time */
+		return (DROPPORT_REQUEST);
+	case 464: /* kpasswd */
+		return (DROPPORT_RESPONSE);
+	}
+	return (DROPPORT_NO);
+}
+#endif /* if NS_CLIENT_DROPPORT */
+
+void
+ns_client_error(ns_client_t *client, isc_result_t result) {
+	dns_message_t *message = NULL;
+	dns_rcode_t rcode;
+	bool trunc = false;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	CTRACE("error");
+
+	message = client->message;
+
+	if (client->rcode_override == -1) {
+		rcode = dns_result_torcode(result);
+	} else {
+		rcode = (dns_rcode_t)(client->rcode_override & 0xfff);
+	}
+
+	if (result == ISC_R_MAXSIZE) {
+		trunc = true;
+	}
+
+#if NS_CLIENT_DROPPORT
+	/*
+	 * Don't send FORMERR to ports on the drop port list.
+	 */
+	if (rcode == dns_rcode_formerr &&
+	    ns_client_dropport(isc_sockaddr_getport(&client->peeraddr)) !=
+		    DROPPORT_NO)
+	{
+		char buf[64];
+		isc_buffer_t b;
+
+		isc_buffer_init(&b, buf, sizeof(buf) - 1);
+		if (dns_rcode_totext(rcode, &b) != ISC_R_SUCCESS) {
+			isc_buffer_putstr(&b, "UNKNOWN RCODE");
+		}
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+			      "dropped error (%.*s) response: suspicious port",
+			      (int)isc_buffer_usedlength(&b), buf);
+		ns_client_drop(client, ISC_R_SUCCESS);
+		return;
+	}
+#endif /* if NS_CLIENT_DROPPORT */
+
+	/*
+	 * Try to rate limit error responses.
+	 */
+	if (client->view != NULL && client->view->rrl != NULL) {
+		bool wouldlog;
+		char log_buf[DNS_RRL_LOG_BUF_LEN];
+		dns_rrl_result_t rrl_result;
+		int loglevel;
+
+		if ((client->sctx->options & NS_SERVER_LOGQUERIES) != 0) {
+			loglevel = DNS_RRL_LOG_DROP;
+		} else {
+			loglevel = ISC_LOG_DEBUG(1);
+		}
+		wouldlog = isc_log_wouldlog(ns_lctx, loglevel);
+		rrl_result = dns_rrl(client->view, NULL, &client->peeraddr,
+				     TCP_CLIENT(client), dns_rdataclass_in,
+				     dns_rdatatype_none, NULL, result,
+				     client->now, wouldlog, log_buf,
+				     sizeof(log_buf));
+		if (rrl_result != DNS_RRL_RESULT_OK) {
+			/*
+			 * Log dropped errors in the query category
+			 * so that they are not lost in silence.
+			 * Starts of rate-limited bursts are logged in
+			 * NS_LOGCATEGORY_RRL.
+			 */
+			if (wouldlog) {
+				ns_client_log(client,
+					      NS_LOGCATEGORY_QUERY_ERRORS,
+					      NS_LOGMODULE_CLIENT, loglevel,
+					      "%s", log_buf);
+			}
+			/*
+			 * Some error responses cannot be 'slipped',
+			 * so don't try to slip any error responses.
+			 */
+			if (!client->view->rrl->log_only) {
+				ns_stats_increment(client->sctx->nsstats,
+						   ns_statscounter_ratedropped);
+				ns_stats_increment(client->sctx->nsstats,
+						   ns_statscounter_dropped);
+				ns_client_drop(client, DNS_R_DROP);
+				return;
+			}
+		}
+	}
+
+	/*
+	 * Message may be an in-progress reply that we had trouble
+	 * with, in which case QR will be set.  We need to clear QR before
+	 * calling dns_message_reply() to avoid triggering an assertion.
+	 */
+	message->flags &= ~DNS_MESSAGEFLAG_QR;
+	/*
+	 * AA and AD shouldn't be set.
+	 */
+	message->flags &= ~(DNS_MESSAGEFLAG_AA | DNS_MESSAGEFLAG_AD);
+	result = dns_message_reply(message, true);
+	if (result != ISC_R_SUCCESS) {
+		/*
+		 * It could be that we've got a query with a good header,
+		 * but a bad question section, so we try again with
+		 * want_question_section set to false.
+		 */
+		result = dns_message_reply(message, false);
+		if (result != ISC_R_SUCCESS) {
+			ns_client_drop(client, result);
+			return;
+		}
+	}
+
+	message->rcode = rcode;
+	if (trunc) {
+		message->flags |= DNS_MESSAGEFLAG_TC;
+	}
+
+	if (rcode == dns_rcode_formerr) {
+		/*
+		 * FORMERR loop avoidance:  If we sent a FORMERR message
+		 * with the same ID to the same client less than two
+		 * seconds ago, assume that we are in an infinite error
+		 * packet dialog with a server for some protocol whose
+		 * error responses look enough like DNS queries to
+		 * elicit a FORMERR response.  Drop a packet to break
+		 * the loop.
+		 */
+		if (isc_sockaddr_equal(&client->peeraddr,
+				       &client->formerrcache.addr) &&
+		    message->id == client->formerrcache.id &&
+		    (isc_time_seconds(&client->requesttime) -
+		     client->formerrcache.time) < 2)
+		{
+			/* Drop packet. */
+			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+				      "possible error packet loop, "
+				      "FORMERR dropped");
+			ns_client_drop(client, result);
+			return;
+		}
+		client->formerrcache.addr = client->peeraddr;
+		client->formerrcache.time =
+			isc_time_seconds(&client->requesttime);
+		client->formerrcache.id = message->id;
+	} else if (rcode == dns_rcode_servfail && client->query.qname != NULL &&
+		   client->view != NULL && client->view->fail_ttl != 0 &&
+		   ((client->attributes & NS_CLIENTATTR_NOSETFC) == 0))
+	{
+		/*
+		 * SERVFAIL caching: store qname/qtype of failed queries
+		 */
+		isc_time_t expire;
+		isc_interval_t i;
+		uint32_t flags = 0;
+
+		if ((message->flags & DNS_MESSAGEFLAG_CD) != 0) {
+			flags = NS_FAILCACHE_CD;
+		}
+
+		isc_interval_set(&i, client->view->fail_ttl, 0);
+		result = isc_time_nowplusinterval(&expire, &i);
+		if (result == ISC_R_SUCCESS) {
+			dns_badcache_add(
+				client->view->failcache, client->query.qname,
+				client->query.qtype, true, flags, &expire);
+		}
+	}
+
+	ns_client_send(client);
+}
+
+isc_result_t
+ns_client_addopt(ns_client_t *client, dns_message_t *message,
+		 dns_rdataset_t **opt) {
+	unsigned char ecs[ECS_SIZE];
+	char nsid[_POSIX_HOST_NAME_MAX + 1], *nsidp = NULL;
+	unsigned char cookie[COOKIE_SIZE];
+	isc_result_t result;
+	dns_view_t *view = NULL;
+	dns_resolver_t *resolver = NULL;
+	uint16_t udpsize;
+	dns_ednsopt_t ednsopts[DNS_EDNSOPTIONS];
+	int count = 0;
+	unsigned int flags;
+	unsigned char expire[4];
+	unsigned char advtimo[2];
+	dns_aclenv_t *env = NULL;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(opt != NULL && *opt == NULL);
+	REQUIRE(message != NULL);
+
+	env = client->manager->aclenv;
+	view = client->view;
+	resolver = (view != NULL) ? view->resolver : NULL;
+	if (resolver != NULL) {
+		udpsize = dns_resolver_getudpsize(resolver);
+	} else {
+		udpsize = client->sctx->udpsize;
+	}
+
+	flags = client->extflags & DNS_MESSAGEEXTFLAG_REPLYPRESERVE;
+
+	/* Set EDNS options if applicable */
+	if (WANTNSID(client)) {
+		if (client->sctx->server_id != NULL) {
+			nsidp = client->sctx->server_id;
+		} else if (client->sctx->usehostname) {
+			result = gethostname(nsid, sizeof(nsid));
+			if (result != ISC_R_SUCCESS) {
+				goto no_nsid;
+			}
+			nsidp = nsid;
+		} else {
+			goto no_nsid;
+		}
+
+		INSIST(count < DNS_EDNSOPTIONS);
+		ednsopts[count].code = DNS_OPT_NSID;
+		ednsopts[count].length = (uint16_t)strlen(nsidp);
+		ednsopts[count].value = (unsigned char *)nsidp;
+		count++;
+	}
+no_nsid:
+	if ((client->attributes & NS_CLIENTATTR_WANTCOOKIE) != 0) {
+		isc_buffer_t buf;
+		isc_stdtime_t now;
+		uint32_t nonce;
+
+		isc_buffer_init(&buf, cookie, sizeof(cookie));
+		isc_stdtime_get(&now);
+
+		isc_random_buf(&nonce, sizeof(nonce));
+
+		compute_cookie(client, now, nonce, client->sctx->secret, &buf);
+
+		INSIST(count < DNS_EDNSOPTIONS);
+		ednsopts[count].code = DNS_OPT_COOKIE;
+		ednsopts[count].length = COOKIE_SIZE;
+		ednsopts[count].value = cookie;
+		count++;
+	}
+	if ((client->attributes & NS_CLIENTATTR_HAVEEXPIRE) != 0) {
+		isc_buffer_t buf;
+
+		INSIST(count < DNS_EDNSOPTIONS);
+
+		isc_buffer_init(&buf, expire, sizeof(expire));
+		isc_buffer_putuint32(&buf, client->expire);
+		ednsopts[count].code = DNS_OPT_EXPIRE;
+		ednsopts[count].length = 4;
+		ednsopts[count].value = expire;
+		count++;
+	}
+	if (((client->attributes & NS_CLIENTATTR_HAVEECS) != 0) &&
+	    (client->ecs.addr.family == AF_INET ||
+	     client->ecs.addr.family == AF_INET6 ||
+	     client->ecs.addr.family == AF_UNSPEC))
+	{
+		isc_buffer_t buf;
+		uint8_t addr[16];
+		uint32_t plen, addrl;
+		uint16_t family = 0;
+
+		/* Add CLIENT-SUBNET option. */
+
+		plen = client->ecs.source;
+
+		/* Round up prefix len to a multiple of 8 */
+		addrl = (plen + 7) / 8;
+
+		switch (client->ecs.addr.family) {
+		case AF_UNSPEC:
+			INSIST(plen == 0);
+			family = 0;
+			break;
+		case AF_INET:
+			INSIST(plen <= 32);
+			family = 1;
+			memmove(addr, &client->ecs.addr.type, addrl);
+			break;
+		case AF_INET6:
+			INSIST(plen <= 128);
+			family = 2;
+			memmove(addr, &client->ecs.addr.type, addrl);
+			break;
+		default:
+			UNREACHABLE();
+		}
+
+		isc_buffer_init(&buf, ecs, sizeof(ecs));
+		/* family */
+		isc_buffer_putuint16(&buf, family);
+		/* source prefix-length */
+		isc_buffer_putuint8(&buf, client->ecs.source);
+		/* scope prefix-length */
+		isc_buffer_putuint8(&buf, client->ecs.scope);
+
+		/* address */
+		if (addrl > 0) {
+			/* Mask off last address byte */
+			if ((plen % 8) != 0) {
+				addr[addrl - 1] &= ~0U << (8 - (plen % 8));
+			}
+			isc_buffer_putmem(&buf, addr, (unsigned)addrl);
+		}
+
+		ednsopts[count].code = DNS_OPT_CLIENT_SUBNET;
+		ednsopts[count].length = addrl + 4;
+		ednsopts[count].value = ecs;
+		count++;
+	}
+	if (TCP_CLIENT(client) && USEKEEPALIVE(client)) {
+		isc_buffer_t buf;
+		uint32_t adv;
+
+		INSIST(count < DNS_EDNSOPTIONS);
+
+		isc_nm_gettimeouts(isc_nmhandle_netmgr(client->handle), NULL,
+				   NULL, NULL, &adv);
+		adv /= 100; /* units of 100 milliseconds */
+		isc_buffer_init(&buf, advtimo, sizeof(advtimo));
+		isc_buffer_putuint16(&buf, (uint16_t)adv);
+		ednsopts[count].code = DNS_OPT_TCP_KEEPALIVE;
+		ednsopts[count].length = 2;
+		ednsopts[count].value = advtimo;
+		count++;
+	}
+
+	if (client->ede != NULL) {
+		INSIST(count < DNS_EDNSOPTIONS);
+		ednsopts[count].code = DNS_OPT_EDE;
+		ednsopts[count].length = client->ede->length;
+		ednsopts[count].value = client->ede->value;
+		count++;
+	}
+
+	/* Padding must be added last */
+	if ((view != NULL) && (view->padding > 0) && WANTPAD(client) &&
+	    (TCP_CLIENT(client) ||
+	     ((client->attributes & NS_CLIENTATTR_HAVECOOKIE) != 0)))
+	{
+		isc_netaddr_t netaddr;
+		int match;
+
+		isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+		result = dns_acl_match(&netaddr, NULL, view->pad_acl, env,
+				       &match, NULL);
+		if (result == ISC_R_SUCCESS && match > 0) {
+			INSIST(count < DNS_EDNSOPTIONS);
+
+			ednsopts[count].code = DNS_OPT_PAD;
+			ednsopts[count].length = 0;
+			ednsopts[count].value = NULL;
+			count++;
+
+			dns_message_setpadding(message, view->padding);
+		}
+	}
+
+	result = dns_message_buildopt(message, opt, 0, udpsize, flags, ednsopts,
+				      count);
+	return (result);
+}
+
+static void
+compute_cookie(ns_client_t *client, uint32_t when, uint32_t nonce,
+	       const unsigned char *secret, isc_buffer_t *buf) {
+	unsigned char digest[ISC_MAX_MD_SIZE] ISC_NONSTRING = { 0 };
+	STATIC_ASSERT(ISC_MAX_MD_SIZE >= ISC_SIPHASH24_TAG_LENGTH, "You need "
+								   "to "
+								   "increase "
+								   "the digest "
+								   "buffer.");
+	STATIC_ASSERT(ISC_MAX_MD_SIZE >= ISC_AES_BLOCK_LENGTH, "You need to "
+							       "increase the "
+							       "digest "
+							       "buffer.");
+
+	switch (client->sctx->cookiealg) {
+	case ns_cookiealg_siphash24: {
+		unsigned char input[16 + 16] ISC_NONSTRING = { 0 };
+		size_t inputlen = 0;
+		isc_netaddr_t netaddr;
+		unsigned char *cp;
+
+		cp = isc_buffer_used(buf);
+		isc_buffer_putmem(buf, client->cookie, 8);
+		isc_buffer_putuint8(buf, NS_COOKIE_VERSION_1);
+		isc_buffer_putuint24(buf, 0); /* Reserved */
+		isc_buffer_putuint32(buf, when);
+
+		memmove(input, cp, 16);
+
+		isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+		switch (netaddr.family) {
+		case AF_INET:
+			cp = (unsigned char *)&netaddr.type.in;
+			memmove(input + 16, cp, 4);
+			inputlen = 20;
+			break;
+		case AF_INET6:
+			cp = (unsigned char *)&netaddr.type.in6;
+			memmove(input + 16, cp, 16);
+			inputlen = 32;
+			break;
+		default:
+			UNREACHABLE();
+		}
+
+		isc_siphash24(secret, input, inputlen, digest);
+		isc_buffer_putmem(buf, digest, 8);
+		break;
+	}
+	case ns_cookiealg_aes: {
+		unsigned char input[4 + 4 + 16] ISC_NONSTRING = { 0 };
+		isc_netaddr_t netaddr;
+		unsigned char *cp;
+		unsigned int i;
+
+		cp = isc_buffer_used(buf);
+		isc_buffer_putmem(buf, client->cookie, 8);
+		isc_buffer_putuint32(buf, nonce);
+		isc_buffer_putuint32(buf, when);
+		memmove(input, cp, 16);
+		isc_aes128_crypt(secret, input, digest);
+		for (i = 0; i < 8; i++) {
+			input[i] = digest[i] ^ digest[i + 8];
+		}
+		isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+		switch (netaddr.family) {
+		case AF_INET:
+			cp = (unsigned char *)&netaddr.type.in;
+			memmove(input + 8, cp, 4);
+			memset(input + 12, 0, 4);
+			isc_aes128_crypt(secret, input, digest);
+			break;
+		case AF_INET6:
+			cp = (unsigned char *)&netaddr.type.in6;
+			memmove(input + 8, cp, 16);
+			isc_aes128_crypt(secret, input, digest);
+			for (i = 0; i < 8; i++) {
+				input[i + 8] = digest[i] ^ digest[i + 8];
+			}
+			isc_aes128_crypt(client->sctx->secret, input + 8,
+					 digest);
+			break;
+		default:
+			UNREACHABLE();
+		}
+		for (i = 0; i < 8; i++) {
+			digest[i] ^= digest[i + 8];
+		}
+		isc_buffer_putmem(buf, digest, 8);
+		break;
+	}
+
+	default:
+		UNREACHABLE();
+	}
+}
+
+static void
+process_cookie(ns_client_t *client, isc_buffer_t *buf, size_t optlen) {
+	ns_altsecret_t *altsecret;
+	unsigned char dbuf[COOKIE_SIZE];
+	unsigned char *old;
+	isc_stdtime_t now;
+	uint32_t when;
+	uint32_t nonce;
+	isc_buffer_t db;
+
+	/*
+	 * If we have already seen a cookie option skip this cookie option.
+	 */
+	if ((!client->sctx->answercookie) ||
+	    (client->attributes & NS_CLIENTATTR_WANTCOOKIE) != 0)
+	{
+		isc_buffer_forward(buf, (unsigned int)optlen);
+		return;
+	}
+
+	client->attributes |= NS_CLIENTATTR_WANTCOOKIE;
+
+	ns_stats_increment(client->sctx->nsstats, ns_statscounter_cookiein);
+
+	if (optlen != COOKIE_SIZE) {
+		/*
+		 * Not our token.
+		 */
+		INSIST(optlen >= 8U);
+		memmove(client->cookie, isc_buffer_current(buf), 8);
+		isc_buffer_forward(buf, (unsigned int)optlen);
+
+		if (optlen == 8U) {
+			ns_stats_increment(client->sctx->nsstats,
+					   ns_statscounter_cookienew);
+		} else {
+			ns_stats_increment(client->sctx->nsstats,
+					   ns_statscounter_cookiebadsize);
+		}
+		return;
+	}
+
+	/*
+	 * Process all of the incoming buffer.
+	 */
+	old = isc_buffer_current(buf);
+	memmove(client->cookie, old, 8);
+	isc_buffer_forward(buf, 8);
+	nonce = isc_buffer_getuint32(buf);
+	when = isc_buffer_getuint32(buf);
+	isc_buffer_forward(buf, 8);
+
+	/*
+	 * Allow for a 5 minute clock skew between servers sharing a secret.
+	 * Only accept COOKIE if we have talked to the client in the last hour.
+	 */
+	isc_stdtime_get(&now);
+	if (isc_serial_gt(when, (now + 300)) || /* In the future. */
+	    isc_serial_lt(when, (now - 3600)))
+	{ /* In the past. */
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_cookiebadtime);
+		return;
+	}
+
+	isc_buffer_init(&db, dbuf, sizeof(dbuf));
+	compute_cookie(client, when, nonce, client->sctx->secret, &db);
+
+	if (isc_safe_memequal(old, dbuf, COOKIE_SIZE)) {
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_cookiematch);
+		client->attributes |= NS_CLIENTATTR_HAVECOOKIE;
+		return;
+	}
+
+	for (altsecret = ISC_LIST_HEAD(client->sctx->altsecrets);
+	     altsecret != NULL; altsecret = ISC_LIST_NEXT(altsecret, link))
+	{
+		isc_buffer_init(&db, dbuf, sizeof(dbuf));
+		compute_cookie(client, when, nonce, altsecret->secret, &db);
+		if (isc_safe_memequal(old, dbuf, COOKIE_SIZE)) {
+			ns_stats_increment(client->sctx->nsstats,
+					   ns_statscounter_cookiematch);
+			client->attributes |= NS_CLIENTATTR_HAVECOOKIE;
+			return;
+		}
+	}
+
+	ns_stats_increment(client->sctx->nsstats,
+			   ns_statscounter_cookienomatch);
+}
+
+static isc_result_t
+process_ecs(ns_client_t *client, isc_buffer_t *buf, size_t optlen) {
+	uint16_t family;
+	uint8_t addrlen, addrbytes, scope, *paddr;
+	isc_netaddr_t caddr;
+
+	/*
+	 * If we have already seen a ECS option skip this ECS option.
+	 */
+	if ((client->attributes & NS_CLIENTATTR_HAVEECS) != 0) {
+		isc_buffer_forward(buf, (unsigned int)optlen);
+		return (ISC_R_SUCCESS);
+	}
+
+	/*
+	 * XXXMUKS: Is there any need to repeat these checks here
+	 * (except query's scope length) when they are done in the OPT
+	 * RDATA fromwire code?
+	 */
+
+	if (optlen < 4U) {
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(2),
+			      "EDNS client-subnet option too short");
+		return (DNS_R_FORMERR);
+	}
+
+	family = isc_buffer_getuint16(buf);
+	addrlen = isc_buffer_getuint8(buf);
+	scope = isc_buffer_getuint8(buf);
+	optlen -= 4;
+
+	if (scope != 0U) {
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(2),
+			      "EDNS client-subnet option: invalid scope");
+		return (DNS_R_OPTERR);
+	}
+
+	memset(&caddr, 0, sizeof(caddr));
+	switch (family) {
+	case 0:
+		/*
+		 * XXXMUKS: In queries, if FAMILY is set to 0, SOURCE
+		 * PREFIX-LENGTH must be 0 and ADDRESS should not be
+		 * present as the address and prefix lengths don't make
+		 * sense because the family is unknown.
+		 */
+		if (addrlen != 0U) {
+			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(2),
+				      "EDNS client-subnet option: invalid "
+				      "address length (%u) for FAMILY=0",
+				      addrlen);
+			return (DNS_R_OPTERR);
+		}
+		caddr.family = AF_UNSPEC;
+		break;
+	case 1:
+		if (addrlen > 32U) {
+			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(2),
+				      "EDNS client-subnet option: invalid "
+				      "address length (%u) for IPv4",
+				      addrlen);
+			return (DNS_R_OPTERR);
+		}
+		caddr.family = AF_INET;
+		break;
+	case 2:
+		if (addrlen > 128U) {
+			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(2),
+				      "EDNS client-subnet option: invalid "
+				      "address length (%u) for IPv6",
+				      addrlen);
+			return (DNS_R_OPTERR);
+		}
+		caddr.family = AF_INET6;
+		break;
+	default:
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(2),
+			      "EDNS client-subnet option: invalid family");
+		return (DNS_R_OPTERR);
+	}
+
+	addrbytes = (addrlen + 7) / 8;
+	if (isc_buffer_remaininglength(buf) < addrbytes) {
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(2),
+			      "EDNS client-subnet option: address too short");
+		return (DNS_R_OPTERR);
+	}
+
+	paddr = (uint8_t *)&caddr.type;
+	if (addrbytes != 0U) {
+		memmove(paddr, isc_buffer_current(buf), addrbytes);
+		isc_buffer_forward(buf, addrbytes);
+		optlen -= addrbytes;
+
+		if ((addrlen % 8) != 0) {
+			uint8_t bits = ~0U << (8 - (addrlen % 8));
+			bits &= paddr[addrbytes - 1];
+			if (bits != paddr[addrbytes - 1]) {
+				return (DNS_R_OPTERR);
+			}
+		}
+	}
+
+	memmove(&client->ecs.addr, &caddr, sizeof(caddr));
+	client->ecs.source = addrlen;
+	client->ecs.scope = 0;
+	client->attributes |= NS_CLIENTATTR_HAVEECS;
+
+	isc_buffer_forward(buf, (unsigned int)optlen);
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+process_keytag(ns_client_t *client, isc_buffer_t *buf, size_t optlen) {
+	if (optlen == 0 || (optlen % 2) != 0) {
+		isc_buffer_forward(buf, (unsigned int)optlen);
+		return (DNS_R_OPTERR);
+	}
+
+	/* Silently drop additional keytag options. */
+	if (client->keytag != NULL) {
+		isc_buffer_forward(buf, (unsigned int)optlen);
+		return (ISC_R_SUCCESS);
+	}
+
+	client->keytag = isc_mem_get(client->mctx, optlen);
+	{
+		client->keytag_len = (uint16_t)optlen;
+		memmove(client->keytag, isc_buffer_current(buf), optlen);
+	}
+	isc_buffer_forward(buf, (unsigned int)optlen);
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+process_opt(ns_client_t *client, dns_rdataset_t *opt) {
+	dns_rdata_t rdata;
+	isc_buffer_t optbuf;
+	isc_result_t result;
+	uint16_t optcode;
+	uint16_t optlen;
+
+	/*
+	 * Set the client's UDP buffer size.
+	 */
+	client->udpsize = opt->rdclass;
+
+	/*
+	 * If the requested UDP buffer size is less than 512,
+	 * ignore it and use 512.
+	 */
+	if (client->udpsize < 512) {
+		client->udpsize = 512;
+	}
+
+	/*
+	 * Get the flags out of the OPT record.
+	 */
+	client->extflags = (uint16_t)(opt->ttl & 0xFFFF);
+
+	/*
+	 * Do we understand this version of EDNS?
+	 *
+	 * XXXRTH need library support for this!
+	 */
+	client->ednsversion = (opt->ttl & 0x00FF0000) >> 16;
+	if (client->ednsversion > DNS_EDNS_VERSION) {
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_badednsver);
+		result = ns_client_addopt(client, client->message,
+					  &client->opt);
+		if (result == ISC_R_SUCCESS) {
+			result = DNS_R_BADVERS;
+		}
+		ns_client_error(client, result);
+		return (result);
+	}
+
+	/* Check for NSID request */
+	result = dns_rdataset_first(opt);
+	if (result == ISC_R_SUCCESS) {
+		dns_rdata_init(&rdata);
+		dns_rdataset_current(opt, &rdata);
+		isc_buffer_init(&optbuf, rdata.data, rdata.length);
+		isc_buffer_add(&optbuf, rdata.length);
+		while (isc_buffer_remaininglength(&optbuf) >= 4) {
+			optcode = isc_buffer_getuint16(&optbuf);
+			optlen = isc_buffer_getuint16(&optbuf);
+			switch (optcode) {
+			case DNS_OPT_NSID:
+				if (!WANTNSID(client)) {
+					ns_stats_increment(
+						client->sctx->nsstats,
+						ns_statscounter_nsidopt);
+				}
+				client->attributes |= NS_CLIENTATTR_WANTNSID;
+				isc_buffer_forward(&optbuf, optlen);
+				break;
+			case DNS_OPT_COOKIE:
+				process_cookie(client, &optbuf, optlen);
+				break;
+			case DNS_OPT_EXPIRE:
+				if (!WANTEXPIRE(client)) {
+					ns_stats_increment(
+						client->sctx->nsstats,
+						ns_statscounter_expireopt);
+				}
+				client->attributes |= NS_CLIENTATTR_WANTEXPIRE;
+				isc_buffer_forward(&optbuf, optlen);
+				break;
+			case DNS_OPT_CLIENT_SUBNET:
+				result = process_ecs(client, &optbuf, optlen);
+				if (result != ISC_R_SUCCESS) {
+					ns_client_error(client, result);
+					return (result);
+				}
+				ns_stats_increment(client->sctx->nsstats,
+						   ns_statscounter_ecsopt);
+				break;
+			case DNS_OPT_TCP_KEEPALIVE:
+				if (!USEKEEPALIVE(client)) {
+					ns_stats_increment(
+						client->sctx->nsstats,
+						ns_statscounter_keepaliveopt);
+				}
+				client->attributes |=
+					NS_CLIENTATTR_USEKEEPALIVE;
+				isc_nmhandle_keepalive(client->handle, true);
+				isc_buffer_forward(&optbuf, optlen);
+				break;
+			case DNS_OPT_PAD:
+				client->attributes |= NS_CLIENTATTR_WANTPAD;
+				ns_stats_increment(client->sctx->nsstats,
+						   ns_statscounter_padopt);
+				isc_buffer_forward(&optbuf, optlen);
+				break;
+			case DNS_OPT_KEY_TAG:
+				result = process_keytag(client, &optbuf,
+							optlen);
+				if (result != ISC_R_SUCCESS) {
+					ns_client_error(client, result);
+					return (result);
+				}
+				ns_stats_increment(client->sctx->nsstats,
+						   ns_statscounter_keytagopt);
+				break;
+			default:
+				ns_stats_increment(client->sctx->nsstats,
+						   ns_statscounter_otheropt);
+				isc_buffer_forward(&optbuf, optlen);
+				break;
+			}
+		}
+	}
+
+	ns_stats_increment(client->sctx->nsstats, ns_statscounter_edns0in);
+	client->attributes |= NS_CLIENTATTR_WANTOPT;
+
+	return (result);
+}
+
+void
+ns__client_reset_cb(void *client0) {
+	ns_client_t *client = client0;
+
+	ns_client_log(client, DNS_LOGCATEGORY_SECURITY, NS_LOGMODULE_CLIENT,
+		      ISC_LOG_DEBUG(3), "reset client");
+
+	/*
+	 * We never started processing this client, possible if we're
+	 * shutting down, just exit.
+	 */
+	if (client->state == NS_CLIENTSTATE_READY) {
+		return;
+	}
+
+	ns_client_endrequest(client);
+	if (client->tcpbuf != NULL) {
+		isc_mem_put(client->manager->send_mctx, client->tcpbuf,
+			    client->tcpbuf_size);
+	}
+
+	if (client->keytag != NULL) {
+		isc_mem_put(client->mctx, client->keytag, client->keytag_len);
+		client->keytag_len = 0;
+	}
+
+	client->state = NS_CLIENTSTATE_READY;
+	INSIST(client->recursionquota == NULL);
+
+#ifdef WANT_SINGLETRACE
+	isc_log_setforcelog(false);
+#endif /* WANT_SINGLETRACE */
+}
+
+void
+ns__client_put_cb(void *client0) {
+	ns_client_t *client = client0;
+
+	ns_client_log(client, DNS_LOGCATEGORY_SECURITY, NS_LOGMODULE_CLIENT,
+		      ISC_LOG_DEBUG(3), "freeing client");
+
+	/*
+	 * Call this first because it requires a valid client.
+	 */
+	ns_query_free(client);
+
+	client->magic = 0;
+	client->shuttingdown = true;
+
+	isc_mem_put(client->manager->send_mctx, client->sendbuf,
+		    NS_CLIENT_SEND_BUFFER_SIZE);
+	if (client->opt != NULL) {
+		INSIST(dns_rdataset_isassociated(client->opt));
+		dns_rdataset_disassociate(client->opt);
+		dns_message_puttemprdataset(client->message, &client->opt);
+	}
+	client_extendederror_reset(client);
+
+	dns_message_detach(&client->message);
+
+	if (client->manager != NULL) {
+		ns_clientmgr_detach(&client->manager);
+	}
+
+	/*
+	 * Detaching the task must be done after unlinking from
+	 * the manager's lists because the manager accesses
+	 * client->task.
+	 */
+	if (client->task != NULL) {
+		isc_task_detach(&client->task);
+	}
+
+	/*
+	 * Destroy the fetchlock mutex that was created in
+	 * ns_query_init().
+	 */
+	isc_mutex_destroy(&client->query.fetchlock);
+
+	if (client->sctx != NULL) {
+		ns_server_detach(&client->sctx);
+	}
+
+	isc_mem_detach(&client->mctx);
+}
+
+/*
+ * Handle an incoming request event from the socket (UDP case)
+ * or tcpmsg (TCP case).
+ */
+void
+ns__client_request(isc_nmhandle_t *handle, isc_result_t eresult,
+		   isc_region_t *region, void *arg) {
+	ns_client_t *client = NULL;
+	isc_result_t result;
+	isc_result_t sigresult = ISC_R_SUCCESS;
+	isc_buffer_t *buffer = NULL;
+	isc_buffer_t tbuffer;
+	dns_rdataset_t *opt = NULL;
+	const dns_name_t *signame = NULL;
+	bool ra; /* Recursion available. */
+	isc_netaddr_t netaddr;
+	int match;
+	dns_messageid_t id;
+	unsigned int flags;
+	bool notimp;
+	size_t reqsize;
+	dns_aclenv_t *env = NULL;
+#ifdef HAVE_DNSTAP
+	dns_dtmsgtype_t dtmsgtype;
+#endif /* ifdef HAVE_DNSTAP */
+	static const char *ra_reasons[] = {
+		"ACLs not processed yet",
+		"no resolver in view",
+		"recursion not enabled for view",
+		"allow-recursion did not match",
+		"allow-query-cache did not match",
+		"allow-recursion-on did not match",
+		"allow-query-cache-on did not match",
+	};
+	enum refusal_reasons {
+		INVALID,
+		NO_RESOLVER,
+		RECURSION_DISABLED,
+		ALLOW_RECURSION,
+		ALLOW_QUERY_CACHE,
+		ALLOW_RECURSION_ON,
+		ALLOW_QUERY_CACHE_ON
+	} ra_refusal_reason = INVALID;
+
+	if (eresult != ISC_R_SUCCESS) {
+		return;
+	}
+
+	client = isc_nmhandle_getdata(handle);
+	if (client == NULL) {
+		ns_interface_t *ifp = (ns_interface_t *)arg;
+		ns_clientmgr_t *clientmgr =
+			ns_interfacemgr_getclientmgr(ifp->mgr);
+
+		INSIST(VALID_MANAGER(clientmgr));
+
+		client = isc_nmhandle_getextra(handle);
+
+		result = ns__client_setup(client, clientmgr, true);
+		if (result != ISC_R_SUCCESS) {
+			return;
+		}
+
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "allocate new client");
+	} else {
+		result = ns__client_setup(client, NULL, false);
+		if (result != ISC_R_SUCCESS) {
+			return;
+		}
+	}
+
+	client->state = NS_CLIENTSTATE_READY;
+
+	if (client->handle == NULL) {
+		isc_nmhandle_setdata(handle, client, ns__client_reset_cb,
+				     ns__client_put_cb);
+		client->handle = handle;
+	}
+
+	if (isc_nmhandle_is_stream(handle)) {
+		client->attributes |= NS_CLIENTATTR_TCP;
+	}
+
+	INSIST(client->recursionquota == NULL);
+
+	INSIST(client->state == NS_CLIENTSTATE_READY);
+
+	(void)atomic_fetch_add_relaxed(&ns_client_requests, 1);
+
+	isc_buffer_init(&tbuffer, region->base, region->length);
+	isc_buffer_add(&tbuffer, region->length);
+	buffer = &tbuffer;
+
+	client->peeraddr = isc_nmhandle_peeraddr(handle);
+	client->peeraddr_valid = true;
+
+	reqsize = isc_buffer_usedlength(buffer);
+
+	client->state = NS_CLIENTSTATE_WORKING;
+
+	TIME_NOW(&client->requesttime);
+	client->tnow = client->requesttime;
+	client->now = isc_time_seconds(&client->tnow);
+
+	isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+
+#if NS_CLIENT_DROPPORT
+	if (ns_client_dropport(isc_sockaddr_getport(&client->peeraddr)) ==
+	    DROPPORT_REQUEST)
+	{
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+			      "dropped request: suspicious port");
+		isc_nm_bad_request(handle);
+		return;
+	}
+#endif /* if NS_CLIENT_DROPPORT */
+
+	env = client->manager->aclenv;
+	if (client->sctx->blackholeacl != NULL &&
+	    (dns_acl_match(&netaddr, NULL, client->sctx->blackholeacl, env,
+			   &match, NULL) == ISC_R_SUCCESS) &&
+	    match > 0)
+	{
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+			      "dropped request: blackholed peer");
+		isc_nm_bad_request(handle);
+		return;
+	}
+
+	ns_client_log(client, NS_LOGCATEGORY_CLIENT, NS_LOGMODULE_CLIENT,
+		      ISC_LOG_DEBUG(3), "%s request",
+		      TCP_CLIENT(client) ? "TCP" : "UDP");
+
+	result = dns_message_peekheader(buffer, &id, &flags);
+	if (result != ISC_R_SUCCESS) {
+		/*
+		 * There isn't enough header to determine whether
+		 * this was a request or a response.  Drop it.
+		 */
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+			      "dropped request: invalid message header");
+		isc_nm_bad_request(handle);
+		return;
+	}
+
+#ifdef WANT_SINGLETRACE
+	if (id == 0) {
+		isc_log_setforcelog(true);
+	}
+#endif /* WANT_SINGLETRACE */
+
+	/*
+	 * The client object handles requests, not responses.
+	 * If this is a UDP response, forward it to the dispatcher.
+	 * If it's a TCP response, discard it here.
+	 */
+	if ((flags & DNS_MESSAGEFLAG_QR) != 0) {
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(10),
+			      "dropped request: unexpected response");
+		isc_nm_bad_request(handle);
+		return;
+	}
+
+	/*
+	 * Update some statistics counters.  Don't count responses.
+	 */
+	if (isc_sockaddr_pf(&client->peeraddr) == PF_INET) {
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_requestv4);
+	} else {
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_requestv6);
+	}
+	if (TCP_CLIENT(client)) {
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_requesttcp);
+		switch (isc_sockaddr_pf(&client->peeraddr)) {
+		case AF_INET:
+			isc_stats_increment(client->sctx->tcpinstats4,
+					    ISC_MIN((int)reqsize / 16, 18));
+			break;
+		case AF_INET6:
+			isc_stats_increment(client->sctx->tcpinstats6,
+					    ISC_MIN((int)reqsize / 16, 18));
+			break;
+		default:
+			UNREACHABLE();
+		}
+	} else {
+		switch (isc_sockaddr_pf(&client->peeraddr)) {
+		case AF_INET:
+			isc_stats_increment(client->sctx->udpinstats4,
+					    ISC_MIN((int)reqsize / 16, 18));
+			break;
+		case AF_INET6:
+			isc_stats_increment(client->sctx->udpinstats6,
+					    ISC_MIN((int)reqsize / 16, 18));
+			break;
+		default:
+			UNREACHABLE();
+		}
+	}
+
+	/*
+	 * It's a request.  Parse it.
+	 */
+	result = dns_message_parse(client->message, buffer, 0);
+	if (result != ISC_R_SUCCESS) {
+		/*
+		 * Parsing the request failed.  Send a response
+		 * (typically FORMERR or SERVFAIL).
+		 */
+		if (result == DNS_R_OPTERR) {
+			(void)ns_client_addopt(client, client->message,
+					       &client->opt);
+		}
+
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+			      "message parsing failed: %s",
+			      isc_result_totext(result));
+		if (result == ISC_R_NOSPACE || result == DNS_R_BADTSIG) {
+			result = DNS_R_FORMERR;
+		}
+		ns_client_error(client, result);
+		return;
+	}
+
+	/*
+	 * Disable pipelined TCP query processing if necessary.
+	 */
+	if (TCP_CLIENT(client) &&
+	    (client->message->opcode != dns_opcode_query ||
+	     (client->sctx->keepresporder != NULL &&
+	      dns_acl_allowed(&netaddr, NULL, client->sctx->keepresporder,
+			      env))))
+	{
+		isc_nm_sequential(handle);
+	}
+
+	dns_opcodestats_increment(client->sctx->opcodestats,
+				  client->message->opcode);
+	switch (client->message->opcode) {
+	case dns_opcode_query:
+	case dns_opcode_update:
+	case dns_opcode_notify:
+		notimp = false;
+		break;
+	case dns_opcode_iquery:
+	default:
+		notimp = true;
+		break;
+	}
+
+	client->message->rcode = dns_rcode_noerror;
+	client->ede = NULL;
+
+	/*
+	 * Deal with EDNS.
+	 */
+	if ((client->sctx->options & NS_SERVER_NOEDNS) != 0) {
+		opt = NULL;
+	} else {
+		opt = dns_message_getopt(client->message);
+	}
+
+	client->ecs.source = 0;
+	client->ecs.scope = 0;
+
+	if (opt != NULL) {
+		/*
+		 * Are returning FORMERR to all EDNS queries?
+		 * Simulate a STD13 compliant server.
+		 */
+		if ((client->sctx->options & NS_SERVER_EDNSFORMERR) != 0) {
+			ns_client_error(client, DNS_R_FORMERR);
+			return;
+		}
+
+		/*
+		 * Are returning NOTIMP to all EDNS queries?
+		 */
+		if ((client->sctx->options & NS_SERVER_EDNSNOTIMP) != 0) {
+			ns_client_error(client, DNS_R_NOTIMP);
+			return;
+		}
+
+		/*
+		 * Are returning REFUSED to all EDNS queries?
+		 */
+		if ((client->sctx->options & NS_SERVER_EDNSREFUSED) != 0) {
+			ns_client_error(client, DNS_R_REFUSED);
+			return;
+		}
+
+		/*
+		 * Are we dropping all EDNS queries?
+		 */
+		if ((client->sctx->options & NS_SERVER_DROPEDNS) != 0) {
+			ns_client_drop(client, ISC_R_SUCCESS);
+			return;
+		}
+
+		result = process_opt(client, opt);
+		if (result != ISC_R_SUCCESS) {
+			return;
+		}
+	}
+
+	if (client->message->rdclass == 0) {
+		if ((client->attributes & NS_CLIENTATTR_WANTCOOKIE) != 0 &&
+		    client->message->opcode == dns_opcode_query &&
+		    client->message->counts[DNS_SECTION_QUESTION] == 0U)
+		{
+			result = dns_message_reply(client->message, true);
+			if (result != ISC_R_SUCCESS) {
+				ns_client_error(client, result);
+				return;
+			}
+
+			if (notimp) {
+				client->message->rcode = dns_rcode_notimp;
+			}
+
+			ns_client_send(client);
+			return;
+		}
+
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+			      "message class could not be determined");
+		ns_client_dumpmessage(client, "message class could not be "
+					      "determined");
+		ns_client_error(client, notimp ? DNS_R_NOTIMP : DNS_R_FORMERR);
+		return;
+	}
+
+	client->destsockaddr = isc_nmhandle_localaddr(handle);
+	isc_netaddr_fromsockaddr(&client->destaddr, &client->destsockaddr);
+
+	result = client->sctx->matchingview(&netaddr, &client->destaddr,
+					    client->message, env, &sigresult,
+					    &client->view);
+	if (result != ISC_R_SUCCESS) {
+		char classname[DNS_RDATACLASS_FORMATSIZE];
+
+		/*
+		 * Do a dummy TSIG verification attempt so that the
+		 * response will have a TSIG if the query did, as
+		 * required by RFC2845.
+		 */
+		isc_buffer_t b;
+		isc_region_t *r;
+
+		dns_message_resetsig(client->message);
+
+		r = dns_message_getrawmessage(client->message);
+		isc_buffer_init(&b, r->base, r->length);
+		isc_buffer_add(&b, r->length);
+		(void)dns_tsig_verify(&b, client->message, NULL, NULL);
+
+		dns_rdataclass_format(client->message->rdclass, classname,
+				      sizeof(classname));
+		ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+			      "no matching view in class '%s'", classname);
+		ns_client_dumpmessage(client, "no matching view in class");
+		ns_client_extendederror(client, DNS_EDE_PROHIBITED, NULL);
+		ns_client_error(client, notimp ? DNS_R_NOTIMP : DNS_R_REFUSED);
+		return;
+	}
+
+	ns_client_log(client, NS_LOGCATEGORY_CLIENT, NS_LOGMODULE_CLIENT,
+		      ISC_LOG_DEBUG(5), "using view '%s'", client->view->name);
+
+	/*
+	 * Check for a signature.  We log bad signatures regardless of
+	 * whether they ultimately cause the request to be rejected or
+	 * not.  We do not log the lack of a signature unless we are
+	 * debugging.
+	 */
+	client->signer = NULL;
+	dns_name_init(&client->signername, NULL);
+	result = dns_message_signer(client->message, &client->signername);
+	if (result != ISC_R_NOTFOUND) {
+		signame = NULL;
+		if (dns_message_gettsig(client->message, &signame) != NULL) {
+			ns_stats_increment(client->sctx->nsstats,
+					   ns_statscounter_tsigin);
+		} else {
+			ns_stats_increment(client->sctx->nsstats,
+					   ns_statscounter_sig0in);
+		}
+	}
+	if (result == ISC_R_SUCCESS) {
+		char namebuf[DNS_NAME_FORMATSIZE];
+		dns_name_format(&client->signername, namebuf, sizeof(namebuf));
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "request has valid signature: %s", namebuf);
+		client->signer = &client->signername;
+	} else if (result == ISC_R_NOTFOUND) {
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "request is not signed");
+	} else if (result == DNS_R_NOIDENTITY) {
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "request is signed by a nonauthoritative key");
+	} else {
+		char tsigrcode[64];
+		isc_buffer_t b;
+		dns_rcode_t status;
+		isc_result_t tresult;
+
+		/* There is a signature, but it is bad. */
+		ns_stats_increment(client->sctx->nsstats,
+				   ns_statscounter_invalidsig);
+		signame = NULL;
+		if (dns_message_gettsig(client->message, &signame) != NULL) {
+			char namebuf[DNS_NAME_FORMATSIZE];
+			char cnamebuf[DNS_NAME_FORMATSIZE];
+			dns_name_format(signame, namebuf, sizeof(namebuf));
+			status = client->message->tsigstatus;
+			isc_buffer_init(&b, tsigrcode, sizeof(tsigrcode) - 1);
+			tresult = dns_tsigrcode_totext(status, &b);
+			INSIST(tresult == ISC_R_SUCCESS);
+			tsigrcode[isc_buffer_usedlength(&b)] = '\0';
+			if (client->message->tsigkey->generated) {
+				dns_name_format(
+					client->message->tsigkey->creator,
+					cnamebuf, sizeof(cnamebuf));
+				ns_client_log(
+					client, DNS_LOGCATEGORY_SECURITY,
+					NS_LOGMODULE_CLIENT, ISC_LOG_ERROR,
+					"request has invalid signature: "
+					"TSIG %s (%s): %s (%s)",
+					namebuf, cnamebuf,
+					isc_result_totext(result), tsigrcode);
+			} else {
+				ns_client_log(
+					client, DNS_LOGCATEGORY_SECURITY,
+					NS_LOGMODULE_CLIENT, ISC_LOG_ERROR,
+					"request has invalid signature: "
+					"TSIG %s: %s (%s)",
+					namebuf, isc_result_totext(result),
+					tsigrcode);
+			}
+		} else {
+			status = client->message->sig0status;
+			isc_buffer_init(&b, tsigrcode, sizeof(tsigrcode) - 1);
+			tresult = dns_tsigrcode_totext(status, &b);
+			INSIST(tresult == ISC_R_SUCCESS);
+			tsigrcode[isc_buffer_usedlength(&b)] = '\0';
+			ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_ERROR,
+				      "request has invalid signature: %s (%s)",
+				      isc_result_totext(result), tsigrcode);
+		}
+
+		/*
+		 * Accept update messages signed by unknown keys so that
+		 * update forwarding works transparently through slaves
+		 * that don't have all the same keys as the primary.
+		 */
+		if (!(client->message->tsigstatus == dns_tsigerror_badkey &&
+		      client->message->opcode == dns_opcode_update))
+		{
+			ns_client_error(client, sigresult);
+			return;
+		}
+	}
+
+	/*
+	 * Decide whether recursive service is available to this client.
+	 * We do this here rather than in the query code so that we can
+	 * set the RA bit correctly on all kinds of responses, not just
+	 * responses to ordinary queries.  Note if you can't query the
+	 * cache there is no point in setting RA.
+	 */
+	ra = false;
+
+	/* must be initialized before ns_client_log uses it as index */
+	if (client->view->resolver == NULL) {
+		ra_refusal_reason = NO_RESOLVER;
+	} else if (!client->view->recursion) {
+		ra_refusal_reason = RECURSION_DISABLED;
+	} else if (ns_client_checkaclsilent(client, NULL,
+					    client->view->recursionacl,
+					    true) != ISC_R_SUCCESS)
+	{
+		ra_refusal_reason = ALLOW_RECURSION;
+	} else if (ns_client_checkaclsilent(client, NULL,
+					    client->view->cacheacl,
+					    true) != ISC_R_SUCCESS)
+	{
+		ra_refusal_reason = ALLOW_QUERY_CACHE;
+	} else if (ns_client_checkaclsilent(client, &client->destaddr,
+					    client->view->recursiononacl,
+					    true) != ISC_R_SUCCESS)
+	{
+		ra_refusal_reason = ALLOW_RECURSION_ON;
+	} else if (ns_client_checkaclsilent(client, &client->destaddr,
+					    client->view->cacheonacl,
+					    true) != ISC_R_SUCCESS)
+	{
+		ra_refusal_reason = ALLOW_QUERY_CACHE_ON;
+	} else {
+		ra = true;
+		client->attributes |= NS_CLIENTATTR_RA;
+	}
+
+	ns_client_log(client, DNS_LOGCATEGORY_SECURITY, NS_LOGMODULE_CLIENT,
+		      ISC_LOG_DEBUG(3),
+		      ra ? "recursion available"
+			 : "recursion not available (%s)",
+		      ra_reasons[ra_refusal_reason]);
+
+	/*
+	 * Adjust maximum UDP response size for this client.
+	 */
+	if (client->udpsize > 512) {
+		dns_peer_t *peer = NULL;
+		uint16_t udpsize = client->view->maxudp;
+		(void)dns_peerlist_peerbyaddr(client->view->peers, &netaddr,
+					      &peer);
+		if (peer != NULL) {
+			dns_peer_getmaxudp(peer, &udpsize);
+		}
+		if (client->udpsize > udpsize) {
+			client->udpsize = udpsize;
+		}
+	}
+
+	/*
+	 * Dispatch the request.
+	 */
+	switch (client->message->opcode) {
+	case dns_opcode_query:
+		CTRACE("query");
+#ifdef HAVE_DNSTAP
+		if (ra && (client->message->flags & DNS_MESSAGEFLAG_RD) != 0) {
+			dtmsgtype = DNS_DTTYPE_CQ;
+		} else {
+			dtmsgtype = DNS_DTTYPE_AQ;
+		}
+
+		dns_dt_send(client->view, dtmsgtype, &client->peeraddr,
+			    &client->destsockaddr, TCP_CLIENT(client), NULL,
+			    &client->requesttime, NULL, buffer);
+#endif /* HAVE_DNSTAP */
+
+		ns_query_start(client, handle);
+		break;
+	case dns_opcode_update:
+		CTRACE("update");
+#ifdef HAVE_DNSTAP
+		dns_dt_send(client->view, DNS_DTTYPE_UQ, &client->peeraddr,
+			    &client->destsockaddr, TCP_CLIENT(client), NULL,
+			    &client->requesttime, NULL, buffer);
+#endif /* HAVE_DNSTAP */
+		ns_client_settimeout(client, 60);
+		ns_update_start(client, handle, sigresult);
+		break;
+	case dns_opcode_notify:
+		CTRACE("notify");
+		ns_client_settimeout(client, 60);
+		ns_notify_start(client, handle);
+		break;
+	case dns_opcode_iquery:
+		CTRACE("iquery");
+		ns_client_error(client, DNS_R_NOTIMP);
+		break;
+	default:
+		CTRACE("unknown opcode");
+		ns_client_error(client, DNS_R_NOTIMP);
+	}
+}
+
+isc_result_t
+ns__client_tcpconn(isc_nmhandle_t *handle, isc_result_t result, void *arg) {
+	ns_interface_t *ifp = (ns_interface_t *)arg;
+	dns_aclenv_t *env = ns_interfacemgr_getaclenv(ifp->mgr);
+	ns_server_t *sctx = ns_interfacemgr_getserver(ifp->mgr);
+	unsigned int tcpquota;
+	isc_sockaddr_t peeraddr;
+	isc_netaddr_t netaddr;
+	int match;
+
+	if (result != ISC_R_SUCCESS) {
+		return (result);
+	}
+
+	if (handle != NULL) {
+		peeraddr = isc_nmhandle_peeraddr(handle);
+		isc_netaddr_fromsockaddr(&netaddr, &peeraddr);
+
+		if (sctx->blackholeacl != NULL &&
+		    (dns_acl_match(&netaddr, NULL, sctx->blackholeacl, env,
+				   &match, NULL) == ISC_R_SUCCESS) &&
+		    match > 0)
+		{
+			return (ISC_R_CONNREFUSED);
+		}
+	}
+
+	tcpquota = isc_quota_getused(&sctx->tcpquota);
+	ns_stats_update_if_greater(sctx->nsstats, ns_statscounter_tcphighwater,
+				   tcpquota);
+
+	return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+ns__client_setup(ns_client_t *client, ns_clientmgr_t *mgr, bool new) {
+	isc_result_t result;
+
+	/*
+	 * Caller must be holding the manager lock.
+	 *
+	 * Note: creating a client does not add the client to the
+	 * manager's client list or set the client's manager pointer.
+	 * The caller is responsible for that.
+	 */
+
+	if (new) {
+		REQUIRE(VALID_MANAGER(mgr));
+		REQUIRE(client != NULL);
+		REQUIRE(mgr->tid == isc_nm_tid());
+
+		*client = (ns_client_t){ .magic = 0, .tid = mgr->tid };
+
+		isc_mem_attach(mgr->mctx, &client->mctx);
+		clientmgr_attach(mgr, &client->manager);
+		ns_server_attach(mgr->sctx, &client->sctx);
+		isc_task_attach(mgr->task, &client->task);
+
+		dns_message_create(client->mctx, DNS_MESSAGE_INTENTPARSE,
+				   &client->message);
+
+		client->sendbuf = isc_mem_get(client->manager->send_mctx,
+					      NS_CLIENT_SEND_BUFFER_SIZE);
+		/*
+		 * Set magic earlier than usual because ns_query_init()
+		 * and the functions it calls will require it.
+		 */
+		client->magic = NS_CLIENT_MAGIC;
+		result = ns_query_init(client);
+		if (result != ISC_R_SUCCESS) {
+			goto cleanup;
+		}
+	} else {
+		REQUIRE(NS_CLIENT_VALID(client));
+		REQUIRE(client->tid == isc_nm_tid());
+
+		ns_clientmgr_t *oldmgr = client->manager;
+		ns_server_t *sctx = client->sctx;
+		isc_task_t *task = client->task;
+		unsigned char *sendbuf = client->sendbuf;
+		dns_message_t *message = client->message;
+		isc_mem_t *oldmctx = client->mctx;
+		ns_query_t query = client->query;
+		int tid = client->tid;
+
+		/*
+		 * Retain these values from the existing client, but
+		 * zero every thing else.
+		 */
+		*client = (ns_client_t){ .magic = 0,
+					 .mctx = oldmctx,
+					 .manager = oldmgr,
+					 .sctx = sctx,
+					 .task = task,
+					 .sendbuf = sendbuf,
+					 .message = message,
+					 .query = query,
+					 .tid = tid };
+	}
+
+	client->query.attributes &= ~NS_QUERYATTR_ANSWERED;
+	client->state = NS_CLIENTSTATE_INACTIVE;
+	client->udpsize = 512;
+	client->ednsversion = -1;
+	dns_name_init(&client->signername, NULL);
+	dns_ecs_init(&client->ecs);
+	isc_sockaddr_any(&client->formerrcache.addr);
+	client->formerrcache.time = 0;
+	client->formerrcache.id = 0;
+	ISC_LINK_INIT(client, rlink);
+	client->rcode_override = -1; /* not set */
+
+	client->magic = NS_CLIENT_MAGIC;
+
+	CTRACE("client_setup");
+
+	return (ISC_R_SUCCESS);
+
+cleanup:
+	if (client->sendbuf != NULL) {
+		isc_mem_put(client->manager->send_mctx, client->sendbuf,
+			    NS_CLIENT_SEND_BUFFER_SIZE);
+	}
+
+	if (client->message != NULL) {
+		dns_message_detach(&client->message);
+	}
+
+	if (client->task != NULL) {
+		isc_task_detach(&client->task);
+	}
+
+	if (client->manager != NULL) {
+		ns_clientmgr_detach(&client->manager);
+	}
+	isc_mem_detach(&client->mctx);
+	if (client->sctx != NULL) {
+		ns_server_detach(&client->sctx);
+	}
+
+	return (result);
+}
+
+bool
+ns_client_shuttingdown(ns_client_t *client) {
+	return (client->shuttingdown);
+}
+
+/***
+ *** Client Manager
+ ***/
+
+static void
+clientmgr_attach(ns_clientmgr_t *source, ns_clientmgr_t **targetp) {
+	int32_t oldrefs;
+
+	REQUIRE(VALID_MANAGER(source));
+	REQUIRE(targetp != NULL && *targetp == NULL);
+
+	oldrefs = isc_refcount_increment0(&source->references);
+	isc_log_write(ns_lctx, NS_LOGCATEGORY_CLIENT, NS_LOGMODULE_CLIENT,
+		      ISC_LOG_DEBUG(3), "clientmgr @%p attach: %d", source,
+		      oldrefs + 1);
+
+	*targetp = source;
+}
+
+void
+ns_clientmgr_detach(ns_clientmgr_t **mp) {
+	int32_t oldrefs;
+	ns_clientmgr_t *mgr = *mp;
+	*mp = NULL;
+
+	oldrefs = isc_refcount_decrement(&mgr->references);
+	isc_log_write(ns_lctx, NS_LOGCATEGORY_CLIENT, NS_LOGMODULE_CLIENT,
+		      ISC_LOG_DEBUG(3), "clientmgr @%p detach: %d", mgr,
+		      oldrefs - 1);
+	if (oldrefs == 1) {
+		clientmgr_destroy(mgr);
+	}
+}
+
+static void
+clientmgr_destroy(ns_clientmgr_t *manager) {
+	MTRACE("clientmgr_destroy");
+
+	isc_refcount_destroy(&manager->references);
+	manager->magic = 0;
+
+	dns_aclenv_detach(&manager->aclenv);
+
+	isc_mutex_destroy(&manager->reclock);
+
+	isc_task_detach(&manager->task);
+	ns_server_detach(&manager->sctx);
+
+	isc_mem_detach(&manager->send_mctx);
+
+	isc_mem_putanddetach(&manager->mctx, manager, sizeof(*manager));
+}
+
+isc_result_t
+ns_clientmgr_create(ns_server_t *sctx, isc_taskmgr_t *taskmgr,
+		    isc_timermgr_t *timermgr, dns_aclenv_t *aclenv, int tid,
+		    ns_clientmgr_t **managerp) {
+	ns_clientmgr_t *manager = NULL;
+	isc_mem_t *mctx = NULL;
+	isc_result_t result;
+
+	isc_mem_create(&mctx);
+	isc_mem_setname(mctx, "clientmgr");
+
+	manager = isc_mem_get(mctx, sizeof(*manager));
+	*manager = (ns_clientmgr_t){ .magic = 0, .mctx = mctx };
+
+	isc_mutex_init(&manager->reclock);
+
+	manager->taskmgr = taskmgr;
+	manager->timermgr = timermgr;
+	manager->tid = tid;
+
+	dns_aclenv_attach(aclenv, &manager->aclenv);
+
+	result = isc_task_create_bound(manager->taskmgr, 20, &manager->task,
+				       manager->tid);
+	RUNTIME_CHECK(result == ISC_R_SUCCESS);
+	isc_task_setname(manager->task, "clientmgr", NULL);
+
+	isc_refcount_init(&manager->references, 1);
+	manager->sctx = NULL;
+	ns_server_attach(sctx, &manager->sctx);
+
+	ISC_LIST_INIT(manager->recursing);
+
+	/*
+	 * We create specialised per-worker memory context specifically
+	 * dedicated and tuned for allocating send buffers as it is a very
+	 * common operation. Not doing so may result in excessive memory
+	 * use in certain workloads.
+	 *
+	 * Please see this thread for more details:
+	 *
+	 * https://github.com/jemalloc/jemalloc/issues/2483
+	 *
+	 * In particular, this information from the jemalloc developers is
+	 * of the most interest:
+	 *
+	 * https://github.com/jemalloc/jemalloc/issues/2483#issuecomment-1639019699
+	 * https://github.com/jemalloc/jemalloc/issues/2483#issuecomment-1698173849
+	 *
+	 * In essence, we use the following memory management strategy:
+	 *
+	 * 1. We use a per-worker memory arena for send buffers memory
+	 * allocation to reduce lock contention (In reality, we create a
+	 * per-client manager arena, but we have one client manager per
+	 * worker).
+	 *
+	 * 2. The automatically created arenas settings remain unchanged
+	 * and may be controlled by users (e.g. by setting the
+	 * "MALLOC_CONF" variable).
+	 *
+	 * 3. We attune the arenas to not use dirty pages cache as the
+	 * cache would have a poor reuse rate, and that is known to
+	 * significantly contribute to excessive memory use.
+	 *
+	 * 4. There is no strict need for the dirty cache, as there is a
+	 * per arena bin for each allocation size, so because we initially
+	 * allocate strictly 64K per send buffer (enough for a DNS
+	 * message), allocations would get directed to one bin (an "object
+	 * pool" or a "slab") maintained within an arena. That is, there
+	 * is an object pool already, specifically to optimise for the
+	 * case of frequent allocations of objects of the given size. The
+	 * object pool should suffice our needs, as we will end up
+	 * recycling the objects from there without the need to back it by
+	 * an additional layer of dirty pages cache. The dirty pages cache
+	 * would have worked better in the case when there are more
+	 * allocation bins involved due to a higher reuse rate (the case
+	 * of a more "generic" memory management).
+	 */
+	isc_mem_create_arena(&manager->send_mctx);
+	isc_mem_setname(manager->send_mctx, "sendbufs");
+	(void)isc_mem_arena_set_dirty_decay_ms(manager->send_mctx, 0);
+	/*
+	 * Disable muzzy pages cache too, as versions < 5.2.0 have it
+	 * enabled by default. The muzzy pages cache goes right below the
+	 * dirty pages cache and backs it.
+	 */
+	(void)isc_mem_arena_set_muzzy_decay_ms(manager->send_mctx, 0);
+
+	manager->magic = MANAGER_MAGIC;
+
+	MTRACE("create");
+
+	*managerp = manager;
+
+	return (ISC_R_SUCCESS);
+}
+
+void
+ns_clientmgr_shutdown(ns_clientmgr_t *manager) {
+	ns_client_t *client;
+
+	REQUIRE(VALID_MANAGER(manager));
+
+	MTRACE("destroy");
+
+	LOCK(&manager->reclock);
+	for (client = ISC_LIST_HEAD(manager->recursing); client != NULL;
+	     client = ISC_LIST_NEXT(client, rlink))
+	{
+		ns_query_cancel(client);
+	}
+	UNLOCK(&manager->reclock);
+}
+
+isc_sockaddr_t *
+ns_client_getsockaddr(ns_client_t *client) {
+	return (&client->peeraddr);
+}
+
+isc_sockaddr_t *
+ns_client_getdestaddr(ns_client_t *client) {
+	return (&client->destsockaddr);
+}
+
+isc_result_t
+ns_client_checkaclsilent(ns_client_t *client, isc_netaddr_t *netaddr,
+			 dns_acl_t *acl, bool default_allow) {
+	isc_result_t result;
+	dns_aclenv_t *env = client->manager->aclenv;
+	isc_netaddr_t tmpnetaddr;
+	int match;
+	isc_sockaddr_t local;
+
+	if (acl == NULL) {
+		if (default_allow) {
+			goto allow;
+		} else {
+			goto deny;
+		}
+	}
+
+	if (netaddr == NULL) {
+		isc_netaddr_fromsockaddr(&tmpnetaddr, &client->peeraddr);
+		netaddr = &tmpnetaddr;
+	}
+
+	local = isc_nmhandle_localaddr(client->handle);
+	result = dns_acl_match_port_transport(
+		netaddr, isc_sockaddr_getport(&local),
+		isc_nm_socket_type(client->handle),
+		isc_nm_has_encryption(client->handle), client->signer, acl, env,
+		&match, NULL);
+
+	if (result != ISC_R_SUCCESS) {
+		goto deny; /* Internal error, already logged. */
+	}
+
+	if (match > 0) {
+		goto allow;
+	}
+	goto deny; /* Negative match or no match. */
+
+allow:
+	return (ISC_R_SUCCESS);
+
+deny:
+	return (DNS_R_REFUSED);
+}
+
+isc_result_t
+ns_client_checkacl(ns_client_t *client, isc_sockaddr_t *sockaddr,
+		   const char *opname, dns_acl_t *acl, bool default_allow,
+		   int log_level) {
+	isc_result_t result;
+	isc_netaddr_t netaddr;
+
+	if (sockaddr != NULL) {
+		isc_netaddr_fromsockaddr(&netaddr, sockaddr);
+	}
+
+	result = ns_client_checkaclsilent(client, sockaddr ? &netaddr : NULL,
+					  acl, default_allow);
+
+	if (result == ISC_R_SUCCESS) {
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(3),
+			      "%s approved", opname);
+	} else {
+		ns_client_extendederror(client, DNS_EDE_PROHIBITED, NULL);
+		ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
+			      NS_LOGMODULE_CLIENT, log_level, "%s denied",
+			      opname);
+	}
+	return (result);
+}
+
+static void
+ns_client_name(ns_client_t *client, char *peerbuf, size_t len) {
+	if (client->peeraddr_valid) {
+		isc_sockaddr_format(&client->peeraddr, peerbuf,
+				    (unsigned int)len);
+	} else {
+		snprintf(peerbuf, len, "@%p", client);
+	}
+}
+
+void
+ns_client_logv(ns_client_t *client, isc_logcategory_t *category,
+	       isc_logmodule_t *module, int level, const char *fmt,
+	       va_list ap) {
+	char msgbuf[4096];
+	char signerbuf[DNS_NAME_FORMATSIZE], qnamebuf[DNS_NAME_FORMATSIZE];
+	char peerbuf[ISC_SOCKADDR_FORMATSIZE];
+	const char *viewname = "";
+	const char *sep1 = "", *sep2 = "", *sep3 = "", *sep4 = "";
+	const char *signer = "", *qname = "";
+	dns_name_t *q = NULL;
+
+	REQUIRE(client != NULL);
+
+	vsnprintf(msgbuf, sizeof(msgbuf), fmt, ap);
+
+	if (client->signer != NULL) {
+		dns_name_format(client->signer, signerbuf, sizeof(signerbuf));
+		sep1 = "/key ";
+		signer = signerbuf;
+	}
+
+	q = client->query.origqname != NULL ? client->query.origqname
+					    : client->query.qname;
+	if (q != NULL) {
+		dns_name_format(q, qnamebuf, sizeof(qnamebuf));
+		sep2 = " (";
+		sep3 = ")";
+		qname = qnamebuf;
+	}
+
+	if (client->view != NULL && strcmp(client->view->name, "_bind") != 0 &&
+	    strcmp(client->view->name, "_default") != 0)
+	{
+		sep4 = ": view ";
+		viewname = client->view->name;
+	}
+
+	if (client->peeraddr_valid) {
+		isc_sockaddr_format(&client->peeraddr, peerbuf,
+				    sizeof(peerbuf));
+	} else {
+		snprintf(peerbuf, sizeof(peerbuf), "(no-peer)");
+	}
+
+	isc_log_write(ns_lctx, category, module, level,
+		      "client @%p %s%s%s%s%s%s%s%s: %s", client, peerbuf, sep1,
+		      signer, sep2, qname, sep3, sep4, viewname, msgbuf);
+}
+
+void
+ns_client_log(ns_client_t *client, isc_logcategory_t *category,
+	      isc_logmodule_t *module, int level, const char *fmt, ...) {
+	va_list ap;
+
+	if (!isc_log_wouldlog(ns_lctx, level)) {
+		return;
+	}
+
+	va_start(ap, fmt);
+	ns_client_logv(client, category, module, level, fmt, ap);
+	va_end(ap);
+}
+
+void
+ns_client_aclmsg(const char *msg, const dns_name_t *name, dns_rdatatype_t type,
+		 dns_rdataclass_t rdclass, char *buf, size_t len) {
+	char namebuf[DNS_NAME_FORMATSIZE];
+	char typebuf[DNS_RDATATYPE_FORMATSIZE];
+	char classbuf[DNS_RDATACLASS_FORMATSIZE];
+
+	dns_name_format(name, namebuf, sizeof(namebuf));
+	dns_rdatatype_format(type, typebuf, sizeof(typebuf));
+	dns_rdataclass_format(rdclass, classbuf, sizeof(classbuf));
+	(void)snprintf(buf, len, "%s '%s/%s/%s'", msg, namebuf, typebuf,
+		       classbuf);
+}
+
+static void
+ns_client_dumpmessage(ns_client_t *client, const char *reason) {
+	isc_buffer_t buffer;
+	char *buf = NULL;
+	int len = 1024;
+	isc_result_t result;
+
+	if (!isc_log_wouldlog(ns_lctx, ISC_LOG_DEBUG(1))) {
+		return;
+	}
+
+	/*
+	 * Note that these are multiline debug messages.  We want a newline
+	 * to appear in the log after each message.
+	 */
+
+	do {
+		buf = isc_mem_get(client->mctx, len);
+		isc_buffer_init(&buffer, buf, len);
+		result = dns_message_totext(
+			client->message, &dns_master_style_debug, 0, &buffer);
+		if (result == ISC_R_NOSPACE) {
+			isc_mem_put(client->mctx, buf, len);
+			len += 1024;
+		} else if (result == ISC_R_SUCCESS) {
+			ns_client_log(client, NS_LOGCATEGORY_CLIENT,
+				      NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
+				      "%s\n%.*s", reason,
+				      (int)isc_buffer_usedlength(&buffer), buf);
+		}
+	} while (result == ISC_R_NOSPACE);
+
+	if (buf != NULL) {
+		isc_mem_put(client->mctx, buf, len);
+	}
+}
+
+void
+ns_client_dumprecursing(FILE *f, ns_clientmgr_t *manager) {
+	ns_client_t *client;
+	char namebuf[DNS_NAME_FORMATSIZE];
+	char original[DNS_NAME_FORMATSIZE];
+	char peerbuf[ISC_SOCKADDR_FORMATSIZE];
+	char typebuf[DNS_RDATATYPE_FORMATSIZE];
+	char classbuf[DNS_RDATACLASS_FORMATSIZE];
+	const char *name;
+	const char *sep;
+	const char *origfor;
+	dns_rdataset_t *rdataset;
+
+	REQUIRE(VALID_MANAGER(manager));
+
+	LOCK(&manager->reclock);
+	client = ISC_LIST_HEAD(manager->recursing);
+	while (client != NULL) {
+		INSIST(client->state == NS_CLIENTSTATE_RECURSING);
+
+		ns_client_name(client, peerbuf, sizeof(peerbuf));
+		if (client->view != NULL &&
+		    strcmp(client->view->name, "_bind") != 0 &&
+		    strcmp(client->view->name, "_default") != 0)
+		{
+			name = client->view->name;
+			sep = ": view ";
+		} else {
+			name = "";
+			sep = "";
+		}
+
+		LOCK(&client->query.fetchlock);
+		INSIST(client->query.qname != NULL);
+		dns_name_format(client->query.qname, namebuf, sizeof(namebuf));
+		if (client->query.qname != client->query.origqname &&
+		    client->query.origqname != NULL)
+		{
+			origfor = " for ";
+			dns_name_format(client->query.origqname, original,
+					sizeof(original));
+		} else {
+			origfor = "";
+			original[0] = '\0';
+		}
+		rdataset = ISC_LIST_HEAD(client->query.qname->list);
+		if (rdataset == NULL && client->query.origqname != NULL) {
+			rdataset = ISC_LIST_HEAD(client->query.origqname->list);
+		}
+		if (rdataset != NULL) {
+			dns_rdatatype_format(rdataset->type, typebuf,
+					     sizeof(typebuf));
+			dns_rdataclass_format(rdataset->rdclass, classbuf,
+					      sizeof(classbuf));
+		} else {
+			strlcpy(typebuf, "-", sizeof(typebuf));
+			strlcpy(classbuf, "-", sizeof(classbuf));
+		}
+		UNLOCK(&client->query.fetchlock);
+		fprintf(f,
+			"; client %s%s%s: id %u '%s/%s/%s'%s%s "
+			"requesttime %u\n",
+			peerbuf, sep, name, client->message->id, namebuf,
+			typebuf, classbuf, origfor, original,
+			isc_time_seconds(&client->requesttime));
+		client = ISC_LIST_NEXT(client, rlink);
+	}
+	UNLOCK(&manager->reclock);
+}
+
+void
+ns_client_qnamereplace(ns_client_t *client, dns_name_t *name) {
+	LOCK(&client->query.fetchlock);
+	if (client->query.restarts > 0) {
+		/*
+		 * client->query.qname was dynamically allocated.
+		 */
+		dns_message_puttempname(client->message, &client->query.qname);
+	}
+	client->query.qname = name;
+	client->query.attributes &= ~NS_QUERYATTR_REDIRECT;
+	UNLOCK(&client->query.fetchlock);
+}
+
+isc_result_t
+ns_client_sourceip(dns_clientinfo_t *ci, isc_sockaddr_t **addrp) {
+	ns_client_t *client = (ns_client_t *)ci->data;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(addrp != NULL);
+
+	*addrp = &client->peeraddr;
+	return (ISC_R_SUCCESS);
+}
+
+dns_rdataset_t *
+ns_client_newrdataset(ns_client_t *client) {
+	dns_rdataset_t *rdataset;
+	isc_result_t result;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+
+	rdataset = NULL;
+	result = dns_message_gettemprdataset(client->message, &rdataset);
+	if (result != ISC_R_SUCCESS) {
+		return (NULL);
+	}
+
+	return (rdataset);
+}
+
+void
+ns_client_putrdataset(ns_client_t *client, dns_rdataset_t **rdatasetp) {
+	dns_rdataset_t *rdataset;
+
+	REQUIRE(NS_CLIENT_VALID(client));
+	REQUIRE(rdatasetp != NULL);
+
+	rdataset = *rdatasetp;
+
+	if (rdataset != NULL) {
+		if (dns_rdataset_isassociated(rdataset)) {
+			dns_rdataset_disassociate(rdataset);
+		}
+		dns_message_puttemprdataset(client->message, rdatasetp);
+	}
+}
+
+isc_result_t
+ns_client_newnamebuf(ns_client_t *client) {
+	isc_buffer_t *dbuf = NULL;
+
+	CTRACE("ns_client_newnamebuf");
+
+	isc_buffer_allocate(client->mctx, &dbuf, 1024);
+	ISC_LIST_APPEND(client->query.namebufs, dbuf, link);
+
+	CTRACE("ns_client_newnamebuf: done");
+	return (ISC_R_SUCCESS);
+}
+
+dns_name_t *
+ns_client_newname(ns_client_t *client, isc_buffer_t *dbuf, isc_buffer_t *nbuf) {
+	dns_name_t *name = NULL;
+	isc_region_t r;
+	isc_result_t result;
+
+	REQUIRE((client->query.attributes & NS_QUERYATTR_NAMEBUFUSED) == 0);
+
+	CTRACE("ns_client_newname");
+
+	result = dns_message_gettempname(client->message, &name);
+	if (result != ISC_R_SUCCESS) {
+		CTRACE("ns_client_newname: "
+		       "dns_message_gettempname failed: done");
+		return (NULL);
+	}
+	isc_buffer_availableregion(dbuf, &r);
+	isc_buffer_init(nbuf, r.base, r.length);
+	dns_name_setbuffer(name, NULL);
+	dns_name_setbuffer(name, nbuf);
+	client->query.attributes |= NS_QUERYATTR_NAMEBUFUSED;
+
+	CTRACE("ns_client_newname: done");
+	return (name);
+}
+
+isc_buffer_t *
+ns_client_getnamebuf(ns_client_t *client) {
+	isc_buffer_t *dbuf;
+	isc_region_t r;
+
+	CTRACE("ns_client_getnamebuf");
+
+	/*%
+	 * Return a name buffer with space for a maximal name, allocating
+	 * a new one if necessary.
+	 */
+	if (ISC_LIST_EMPTY(client->query.namebufs)) {
+		ns_client_newnamebuf(client);
+	}
+
+	dbuf = ISC_LIST_TAIL(client->query.namebufs);
+	INSIST(dbuf != NULL);
+	isc_buffer_availableregion(dbuf, &r);
+	if (r.length < DNS_NAME_MAXWIRE) {
+		ns_client_newnamebuf(client);
+		dbuf = ISC_LIST_TAIL(client->query.namebufs);
+		isc_buffer_availableregion(dbuf, &r);
+		INSIST(r.length >= 255);
+	}
+	CTRACE("ns_client_getnamebuf: done");
+	return (dbuf);
+}
+
+void
+ns_client_keepname(ns_client_t *client, dns_name_t *name, isc_buffer_t *dbuf) {
+	isc_region_t r;
+
+	CTRACE("ns_client_keepname");
+
+	/*%
+	 * 'name' is using space in 'dbuf', but 'dbuf' has not yet been
+	 * adjusted to take account of that.  We do the adjustment.
+	 */
+	REQUIRE((client->query.attributes & NS_QUERYATTR_NAMEBUFUSED) != 0);
+
+	dns_name_toregion(name, &r);
+	isc_buffer_add(dbuf, r.length);
+	dns_name_setbuffer(name, NULL);
+	client->query.attributes &= ~NS_QUERYATTR_NAMEBUFUSED;
+}
+
+void
+ns_client_releasename(ns_client_t *client, dns_name_t **namep) {
+	/*%
+	 * 'name' is no longer needed.  Return it to our pool of temporary
+	 * names.  If it is using a name buffer, relinquish its exclusive
+	 * rights on the buffer.
+	 */
+
+	CTRACE("ns_client_releasename");
+	client->query.attributes &= ~NS_QUERYATTR_NAMEBUFUSED;
+	dns_message_puttempname(client->message, namep);
+	CTRACE("ns_client_releasename: done");
+}
+
+isc_result_t
+ns_client_newdbversion(ns_client_t *client, unsigned int n) {
+	unsigned int i;
+	ns_dbversion_t *dbversion = NULL;
+
+	for (i = 0; i < n; i++) {
+		dbversion = isc_mem_get(client->mctx, sizeof(*dbversion));
+		*dbversion = (ns_dbversion_t){ 0 };
+		ISC_LIST_INITANDAPPEND(client->query.freeversions, dbversion,
+				       link);
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+static ns_dbversion_t *
+client_getdbversion(ns_client_t *client) {
+	ns_dbversion_t *dbversion = NULL;
+
+	if (ISC_LIST_EMPTY(client->query.freeversions)) {
+		ns_client_newdbversion(client, 1);
+	}
+	dbversion = ISC_LIST_HEAD(client->query.freeversions);
+	INSIST(dbversion != NULL);
+	ISC_LIST_UNLINK(client->query.freeversions, dbversion, link);
+
+	return (dbversion);
+}
+
+ns_dbversion_t *
+ns_client_findversion(ns_client_t *client, dns_db_t *db) {
+	ns_dbversion_t *dbversion;
+
+	for (dbversion = ISC_LIST_HEAD(client->query.activeversions);
+	     dbversion != NULL; dbversion = ISC_LIST_NEXT(dbversion, link))
+	{
+		if (dbversion->db == db) {
+			break;
+		}
+	}
+
+	if (dbversion == NULL) {
+		/*
+		 * This is a new zone for this query.  Add it to
+		 * the active list.
+		 */
+		dbversion = client_getdbversion(client);
+		if (dbversion == NULL) {
+			return (NULL);
+		}
+		dns_db_attach(db, &dbversion->db);
+		dns_db_currentversion(db, &dbversion->version);
+		dbversion->acl_checked = false;
+		dbversion->queryok = false;
+		ISC_LIST_APPEND(client->query.activeversions, dbversion, link);
+	}
+
+	return (dbversion);
+}