/*
 * Copyright (C) 2004-2012  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1999-2003  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: query.c,v 1.353.8.24 2012/02/07 01:14:39 marka Exp $ */

/*! \file */

#include <config.h>

#include <string.h>

#include <isc/hex.h>
#include <isc/mem.h>
#include <isc/stats.h>
#include <isc/util.h>

#include <dns/adb.h>
#include <dns/byaddr.h>
#include <dns/db.h>
#include <dns/dlz.h>
#include <dns/dns64.h>
#include <dns/dnssec.h>
#include <dns/events.h>
#include <dns/message.h>
#include <dns/ncache.h>
#include <dns/nsec3.h>
#include <dns/order.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rdatalist.h>
#include <dns/rdataset.h>
#include <dns/rdatasetiter.h>
#include <dns/rdatastruct.h>
#include <dns/rdatatype.h>
#include <dns/resolver.h>
#include <dns/result.h>
#include <dns/stats.h>
#include <dns/tkey.h>
#include <dns/view.h>
#include <dns/zone.h>
#include <dns/zt.h>

#include <named/client.h>
#include <named/globals.h>
#include <named/log.h>
#include <named/server.h>
#include <named/sortlist.h>
#include <named/xfrout.h>

#if 0
/*
 * It has been recommended that DNS64 be changed to return excluded
 * AAAA addresses if DNS64 synthesis does not occur.  This minimises
 * the impact on the lookup results.  While most DNS AAAA lookups are
 * done to send IP packets to a host, not all of them are and filtering
 * excluded addresses has a negative impact on those uses.
 */
#define dns64_bis_return_excluded_addresses 1
#endif

/*% Partial answer? */
#define PARTIALANSWER(c)	(((c)->query.attributes & \
				  NS_QUERYATTR_PARTIALANSWER) != 0)
/*% Use Cache? */
#define USECACHE(c)		(((c)->query.attributes & \
				  NS_QUERYATTR_CACHEOK) != 0)
/*% Recursion OK? */
#define RECURSIONOK(c)		(((c)->query.attributes & \
				  NS_QUERYATTR_RECURSIONOK) != 0)
/*% Recursing? */
#define RECURSING(c)		(((c)->query.attributes & \
				  NS_QUERYATTR_RECURSING) != 0)
/*% Cache glue ok? */
#define CACHEGLUEOK(c)		(((c)->query.attributes & \
				  NS_QUERYATTR_CACHEGLUEOK) != 0)
/*% Want Recursion? */
#define WANTRECURSION(c)	(((c)->query.attributes & \
				  NS_QUERYATTR_WANTRECURSION) != 0)
/*% Want DNSSEC? */
#define WANTDNSSEC(c)		(((c)->attributes & \
				  NS_CLIENTATTR_WANTDNSSEC) != 0)
/*% No authority? */
#define NOAUTHORITY(c)		(((c)->query.attributes & \
				  NS_QUERYATTR_NOAUTHORITY) != 0)
/*% No additional? */
#define NOADDITIONAL(c)		(((c)->query.attributes & \
				  NS_QUERYATTR_NOADDITIONAL) != 0)
/*% Secure? */
#define SECURE(c)		(((c)->query.attributes & \
				  NS_QUERYATTR_SECURE) != 0)
/*% DNS64 A lookup? */
#define DNS64(c)		(((c)->query.attributes & \
				  NS_QUERYATTR_DNS64) != 0)

#define DNS64EXCLUDE(c)		(((c)->query.attributes & \
				  NS_QUERYATTR_DNS64EXCLUDE) != 0)

/*% No QNAME Proof? */
#define NOQNAME(r)		(((r)->attributes & \
				  DNS_RDATASETATTR_NOQNAME) != 0)

#if 0
#define CTRACE(m)       isc_log_write(ns_g_lctx, \
				      NS_LOGCATEGORY_CLIENT, \
				      NS_LOGMODULE_QUERY, \
				      ISC_LOG_DEBUG(3), \
				      "client %p: %s", client, (m))
#define QTRACE(m)       isc_log_write(ns_g_lctx, \
				      NS_LOGCATEGORY_GENERAL, \
				      NS_LOGMODULE_QUERY, \
				      ISC_LOG_DEBUG(3), \
				      "query %p: %s", query, (m))
#else
#define CTRACE(m) ((void)m)
#define QTRACE(m) ((void)m)
#endif

#define DNS_GETDB_NOEXACT 0x01U
#define DNS_GETDB_NOLOG 0x02U
#define DNS_GETDB_PARTIAL 0x04U
#define DNS_GETDB_IGNOREACL 0x08U

#define PENDINGOK(x)	(((x) & DNS_DBFIND_PENDINGOK) != 0)

typedef struct client_additionalctx {
	ns_client_t *client;
	dns_rdataset_t *rdataset;
} client_additionalctx_t;

static isc_result_t
query_find(ns_client_t *client, dns_fetchevent_t *event, dns_rdatatype_t qtype);

static isc_boolean_t
validate(ns_client_t *client, dns_db_t *db, dns_name_t *name,
	 dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset);

static void
query_findclosestnsec3(dns_name_t *qname, dns_db_t *db,
		       dns_dbversion_t *version, ns_client_t *client,
		       dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
		       dns_name_t *fname, isc_boolean_t exact,
		       dns_name_t *found);

static inline void
log_queryerror(ns_client_t *client, isc_result_t result, int line, int level);

static void
rpz_st_clear(ns_client_t *client);

/*%
 * Increment query statistics counters.
 */
static inline void
inc_stats(ns_client_t *client, isc_statscounter_t counter) {
	dns_zone_t *zone = client->query.authzone;

	isc_stats_increment(ns_g_server->nsstats, counter);

	if (zone != NULL) {
		isc_stats_t *zonestats = dns_zone_getrequeststats(zone);
		if (zonestats != NULL)
			isc_stats_increment(zonestats, counter);
	}
}

static void
query_send(ns_client_t *client) {
	isc_statscounter_t counter;
	if ((client->message->flags & DNS_MESSAGEFLAG_AA) == 0)
		inc_stats(client, dns_nsstatscounter_nonauthans);
	else
		inc_stats(client, dns_nsstatscounter_authans);
	if (client->message->rcode == dns_rcode_noerror) {
		if (ISC_LIST_EMPTY(client->message->sections[DNS_SECTION_ANSWER])) {
			if (client->query.isreferral) {
				counter = dns_nsstatscounter_referral;
			} else {
				counter = dns_nsstatscounter_nxrrset;
			}
		} else {
			counter = dns_nsstatscounter_success;
		}
	} else if (client->message->rcode == dns_rcode_nxdomain) {
		counter = dns_nsstatscounter_nxdomain;
	} else {
		/* We end up here in case of YXDOMAIN, and maybe others */
		counter = dns_nsstatscounter_failure;
	}
	inc_stats(client, counter);
	ns_client_send(client);
}

static void
query_error(ns_client_t *client, isc_result_t result, int line) {
	int loglevel = ISC_LOG_DEBUG(3);

	switch (result) {
	case DNS_R_SERVFAIL:
		loglevel = ISC_LOG_DEBUG(1);
		inc_stats(client, dns_nsstatscounter_servfail);
		break;
	case DNS_R_FORMERR:
		inc_stats(client, dns_nsstatscounter_formerr);
		break;
	default:
		inc_stats(client, dns_nsstatscounter_failure);
		break;
	}

	log_queryerror(client, result, line, loglevel);

	ns_client_error(client, result);
}

static void
query_next(ns_client_t *client, isc_result_t result) {
	if (result == DNS_R_DUPLICATE)
		inc_stats(client, dns_nsstatscounter_duplicate);
	else if (result == DNS_R_DROP)
		inc_stats(client, dns_nsstatscounter_dropped);
	else
		inc_stats(client, dns_nsstatscounter_failure);
	ns_client_next(client, result);
}

static inline void
query_freefreeversions(ns_client_t *client, isc_boolean_t everything) {
	ns_dbversion_t *dbversion, *dbversion_next;
	unsigned int i;

	for (dbversion = ISC_LIST_HEAD(client->query.freeversions), i = 0;
	     dbversion != NULL;
	     dbversion = dbversion_next, i++)
	{
		dbversion_next = ISC_LIST_NEXT(dbversion, link);
		/*
		 * If we're not freeing everything, we keep the first three
		 * dbversions structures around.
		 */
		if (i > 3 || everything) {
			ISC_LIST_UNLINK(client->query.freeversions, dbversion,
					link);
			isc_mem_put(client->mctx, dbversion,
				    sizeof(*dbversion));
		}
	}
}

void
ns_query_cancel(ns_client_t *client) {
	LOCK(&client->query.fetchlock);
	if (client->query.fetch != NULL) {
		dns_resolver_cancelfetch(client->query.fetch);

		client->query.fetch = NULL;
	}
	UNLOCK(&client->query.fetchlock);
}

static inline void
query_putrdataset(ns_client_t *client, dns_rdataset_t **rdatasetp) {
	dns_rdataset_t *rdataset = *rdatasetp;

	CTRACE("query_putrdataset");
	if (rdataset != NULL) {
		if (dns_rdataset_isassociated(rdataset))
			dns_rdataset_disassociate(rdataset);
		dns_message_puttemprdataset(client->message, rdatasetp);
	}
	CTRACE("query_putrdataset: done");
}

static inline void
query_reset(ns_client_t *client, isc_boolean_t everything) {
	isc_buffer_t *dbuf, *dbuf_next;
	ns_dbversion_t *dbversion, *dbversion_next;

	/*%
	 * Reset the query state of a client to its default state.
	 */

	/*
	 * Cancel the fetch if it's running.
	 */
	ns_query_cancel(client);

	/*
	 * Cleanup any active versions.
	 */
	for (dbversion = ISC_LIST_HEAD(client->query.activeversions);
	     dbversion != NULL;
	     dbversion = dbversion_next) {
		dbversion_next = ISC_LIST_NEXT(dbversion, link);
		dns_db_closeversion(dbversion->db, &dbversion->version,
				    ISC_FALSE);
		dns_db_detach(&dbversion->db);
		ISC_LIST_INITANDAPPEND(client->query.freeversions,
				      dbversion, link);
	}
	ISC_LIST_INIT(client->query.activeversions);

	if (client->query.authdb != NULL)
		dns_db_detach(&client->query.authdb);
	if (client->query.authzone != NULL)
		dns_zone_detach(&client->query.authzone);

	if (client->query.dns64_aaaa != NULL)
		query_putrdataset(client, &client->query.dns64_aaaa);
	if (client->query.dns64_sigaaaa != NULL)
		query_putrdataset(client, &client->query.dns64_sigaaaa);
	if (client->query.dns64_aaaaok != NULL) {
		isc_mem_put(client->mctx, client->query.dns64_aaaaok,
			    client->query.dns64_aaaaoklen *
			    sizeof(isc_boolean_t));
		client->query.dns64_aaaaok =  NULL;
		client->query.dns64_aaaaoklen =  0;
	}

	query_freefreeversions(client, everything);

	for (dbuf = ISC_LIST_HEAD(client->query.namebufs);
	     dbuf != NULL;
	     dbuf = dbuf_next) {
		dbuf_next = ISC_LIST_NEXT(dbuf, link);
		if (dbuf_next != NULL || everything) {
			ISC_LIST_UNLINK(client->query.namebufs, dbuf, link);
			isc_buffer_free(&dbuf);
		}
	}

	if (client->query.restarts > 0) {
		/*
		 * client->query.qname was dynamically allocated.
		 */
		dns_message_puttempname(client->message,
					&client->query.qname);
	}
	client->query.qname = NULL;
	client->query.attributes = (NS_QUERYATTR_RECURSIONOK |
				    NS_QUERYATTR_CACHEOK |
				    NS_QUERYATTR_SECURE);
	client->query.restarts = 0;
	client->query.timerset = ISC_FALSE;
	if (client->query.rpz_st != NULL) {
		rpz_st_clear(client);
		if (everything) {
			isc_mem_put(client->mctx, client->query.rpz_st,
				    sizeof(*client->query.rpz_st));
			client->query.rpz_st = NULL;
		}
	}
	client->query.origqname = NULL;
	client->query.dboptions = 0;
	client->query.fetchoptions = 0;
	client->query.gluedb = NULL;
	client->query.authdbset = ISC_FALSE;
	client->query.isreferral = ISC_FALSE;
	client->query.dns64_options = 0;
	client->query.dns64_ttl = ISC_UINT32_MAX;
}

static void
query_next_callback(ns_client_t *client) {
	query_reset(client, ISC_FALSE);
}

void
ns_query_free(ns_client_t *client) {
	query_reset(client, ISC_TRUE);
}

static inline isc_result_t
query_newnamebuf(ns_client_t *client) {
	isc_buffer_t *dbuf;
	isc_result_t result;

	CTRACE("query_newnamebuf");
	/*%
	 * Allocate a name buffer.
	 */

	dbuf = NULL;
	result = isc_buffer_allocate(client->mctx, &dbuf, 1024);
	if (result != ISC_R_SUCCESS) {
		CTRACE("query_newnamebuf: isc_buffer_allocate failed: done");
		return (result);
	}
	ISC_LIST_APPEND(client->query.namebufs, dbuf, link);

	CTRACE("query_newnamebuf: done");
	return (ISC_R_SUCCESS);
}

static inline isc_buffer_t *
query_getnamebuf(ns_client_t *client) {
	isc_buffer_t *dbuf;
	isc_result_t result;
	isc_region_t r;

	CTRACE("query_getnamebuf");
	/*%
	 * Return a name buffer with space for a maximal name, allocating
	 * a new one if necessary.
	 */

	if (ISC_LIST_EMPTY(client->query.namebufs)) {
		result = query_newnamebuf(client);
		if (result != ISC_R_SUCCESS) {
		    CTRACE("query_getnamebuf: query_newnamebuf failed: done");
			return (NULL);
		}
	}

	dbuf = ISC_LIST_TAIL(client->query.namebufs);
	INSIST(dbuf != NULL);
	isc_buffer_availableregion(dbuf, &r);
	if (r.length < 255) {
		result = query_newnamebuf(client);
		if (result != ISC_R_SUCCESS) {
		    CTRACE("query_getnamebuf: query_newnamebuf failed: done");
			return (NULL);

		}
		dbuf = ISC_LIST_TAIL(client->query.namebufs);
		isc_buffer_availableregion(dbuf, &r);
		INSIST(r.length >= 255);
	}
	CTRACE("query_getnamebuf: done");
	return (dbuf);
}

static inline void
query_keepname(ns_client_t *client, dns_name_t *name, isc_buffer_t *dbuf) {
	isc_region_t r;

	CTRACE("query_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;
}

static inline void
query_releasename(ns_client_t *client, dns_name_t **namep) {
	dns_name_t *name = *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("query_releasename");
	if (dns_name_hasbuffer(name)) {
		INSIST((client->query.attributes & NS_QUERYATTR_NAMEBUFUSED)
		       != 0);
		client->query.attributes &= ~NS_QUERYATTR_NAMEBUFUSED;
	}
	dns_message_puttempname(client->message, namep);
	CTRACE("query_releasename: done");
}

static inline dns_name_t *
query_newname(ns_client_t *client, isc_buffer_t *dbuf,
	      isc_buffer_t *nbuf)
{
	dns_name_t *name;
	isc_region_t r;
	isc_result_t result;

	REQUIRE((client->query.attributes & NS_QUERYATTR_NAMEBUFUSED) == 0);

	CTRACE("query_newname");
	name = NULL;
	result = dns_message_gettempname(client->message, &name);
	if (result != ISC_R_SUCCESS) {
		CTRACE("query_newname: dns_message_gettempname failed: done");
		return (NULL);
	}
	isc_buffer_availableregion(dbuf, &r);
	isc_buffer_init(nbuf, r.base, r.length);
	dns_name_init(name, NULL);
	dns_name_setbuffer(name, nbuf);
	client->query.attributes |= NS_QUERYATTR_NAMEBUFUSED;

	CTRACE("query_newname: done");
	return (name);
}

static inline dns_rdataset_t *
query_newrdataset(ns_client_t *client) {
	dns_rdataset_t *rdataset;
	isc_result_t result;

	CTRACE("query_newrdataset");
	rdataset = NULL;
	result = dns_message_gettemprdataset(client->message, &rdataset);
	if (result != ISC_R_SUCCESS) {
	  CTRACE("query_newrdataset: "
		 "dns_message_gettemprdataset failed: done");
		return (NULL);
	}
	dns_rdataset_init(rdataset);

	CTRACE("query_newrdataset: done");
	return (rdataset);
}

static inline isc_result_t
query_newdbversion(ns_client_t *client, unsigned int n) {
	unsigned int i;
	ns_dbversion_t *dbversion;

	for (i = 0; i < n; i++) {
		dbversion = isc_mem_get(client->mctx, sizeof(*dbversion));
		if (dbversion != NULL) {
			dbversion->db = NULL;
			dbversion->version = NULL;
			ISC_LIST_INITANDAPPEND(client->query.freeversions,
					      dbversion, link);
		} else {
			/*
			 * We only return ISC_R_NOMEMORY if we couldn't
			 * allocate anything.
			 */
			if (i == 0)
				return (ISC_R_NOMEMORY);
			else
				return (ISC_R_SUCCESS);
		}
	}

	return (ISC_R_SUCCESS);
}

static inline ns_dbversion_t *
query_getdbversion(ns_client_t *client) {
	isc_result_t result;
	ns_dbversion_t *dbversion;

	if (ISC_LIST_EMPTY(client->query.freeversions)) {
		result = query_newdbversion(client, 1);
		if (result != ISC_R_SUCCESS)
			return (NULL);
	}
	dbversion = ISC_LIST_HEAD(client->query.freeversions);
	INSIST(dbversion != NULL);
	ISC_LIST_UNLINK(client->query.freeversions, dbversion, link);

	return (dbversion);
}

isc_result_t
ns_query_init(ns_client_t *client) {
	isc_result_t result;

	ISC_LIST_INIT(client->query.namebufs);
	ISC_LIST_INIT(client->query.activeversions);
	ISC_LIST_INIT(client->query.freeversions);
	client->query.restarts = 0;
	client->query.timerset = ISC_FALSE;
	client->query.rpz_st = NULL;
	client->query.qname = NULL;
	result = isc_mutex_init(&client->query.fetchlock);
	if (result != ISC_R_SUCCESS)
		return (result);
	client->query.fetch = NULL;
	client->query.authdb = NULL;
	client->query.authzone = NULL;
	client->query.authdbset = ISC_FALSE;
	client->query.isreferral = ISC_FALSE;
	client->query.dns64_aaaa = NULL;
	client->query.dns64_sigaaaa = NULL;
	client->query.dns64_aaaaok = NULL;
	client->query.dns64_aaaaoklen = 0;
	query_reset(client, ISC_FALSE);
	result = query_newdbversion(client, 3);
	if (result != ISC_R_SUCCESS) {
		DESTROYLOCK(&client->query.fetchlock);
		return (result);
	}
	result = query_newnamebuf(client);
	if (result != ISC_R_SUCCESS)
		query_freefreeversions(client, ISC_TRUE);

	return (result);
}

static inline ns_dbversion_t *
query_findversion(ns_client_t *client, dns_db_t *db)
{
	ns_dbversion_t *dbversion;

	/*%
	 * We may already have done a query related to this
	 * database.  If so, we must be sure to make subsequent
	 * queries from the same version.
	 */
	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 = query_getdbversion(client);
		if (dbversion == NULL)
			return (NULL);
		dns_db_attach(db, &dbversion->db);
		dns_db_currentversion(db, &dbversion->version);
		dbversion->acl_checked = ISC_FALSE;
		dbversion->queryok = ISC_FALSE;
		ISC_LIST_APPEND(client->query.activeversions,
				dbversion, link);
	}

	return (dbversion);
}

static inline isc_result_t
query_validatezonedb(ns_client_t *client, dns_name_t *name,
		     dns_rdatatype_t qtype, unsigned int options,
		     dns_zone_t *zone, dns_db_t *db,
		     dns_dbversion_t **versionp)
{
	isc_result_t result;
	dns_acl_t *queryacl;
	ns_dbversion_t *dbversion;

	REQUIRE(zone != NULL);
	REQUIRE(db != NULL);

	/*
	 * This limits our searching to the zone where the first name
	 * (the query target) was looked for.  This prevents following
	 * CNAMES or DNAMES into other zones and prevents returning
	 * additional data from other zones.
	 */
	if (!client->view->additionalfromauth &&
	    client->query.authdbset &&
	    db != client->query.authdb)
		return (DNS_R_REFUSED);

	/*
	 * Non recursive query to a static-stub zone is prohibited; its
	 * zone content is not public data, but a part of local configuration
	 * and should not be disclosed.
	 */
	if (dns_zone_gettype(zone) == dns_zone_staticstub &&
	    !RECURSIONOK(client)) {
		return (DNS_R_REFUSED);
	}

	/*
	 * If the zone has an ACL, we'll check it, otherwise
	 * we use the view's "allow-query" ACL.  Each ACL is only checked
	 * once per query.
	 *
	 * Also, get the database version to use.
	 */

	/*
	 * Get the current version of this database.
	 */
	dbversion = query_findversion(client, db);
	if (dbversion == NULL)
		return (DNS_R_SERVFAIL);

	if ((options & DNS_GETDB_IGNOREACL) != 0)
		goto approved;
	if (dbversion->acl_checked) {
		if (!dbversion->queryok)
			return (DNS_R_REFUSED);
		goto approved;
	}

	queryacl = dns_zone_getqueryacl(zone);
	if (queryacl == NULL) {
		queryacl = client->view->queryacl;
		if ((client->query.attributes &
		     NS_QUERYATTR_QUERYOKVALID) != 0) {
			/*
			 * We've evaluated the view's queryacl already.  If
			 * NS_QUERYATTR_QUERYOK is set, then the client is
			 * allowed to make queries, otherwise the query should
			 * be refused.
			 */
			dbversion->acl_checked = ISC_TRUE;
			if ((client->query.attributes &
			     NS_QUERYATTR_QUERYOK) == 0) {
				dbversion->queryok = ISC_FALSE;
				return (DNS_R_REFUSED);
			}
			dbversion->queryok = ISC_TRUE;
			goto approved;
		}
	}

	result = ns_client_checkaclsilent(client, NULL, queryacl, ISC_TRUE);
	if ((options & DNS_GETDB_NOLOG) == 0) {
		char msg[NS_CLIENT_ACLMSGSIZE("query")];
		if (result == ISC_R_SUCCESS) {
			if (isc_log_wouldlog(ns_g_lctx, ISC_LOG_DEBUG(3))) {
				ns_client_aclmsg("query", name, qtype,
						 client->view->rdclass,
						 msg, sizeof(msg));
				ns_client_log(client,
					      DNS_LOGCATEGORY_SECURITY,
					      NS_LOGMODULE_QUERY,
					      ISC_LOG_DEBUG(3),
					      "%s approved", msg);
			}
		} else {
			ns_client_aclmsg("query", name, qtype,
					 client->view->rdclass,
					 msg, sizeof(msg));
			ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
				      NS_LOGMODULE_QUERY, ISC_LOG_INFO,
				      "%s denied", msg);
		}
	}

	if (queryacl == client->view->queryacl) {
		if (result == ISC_R_SUCCESS) {
			/*
			 * We were allowed by the default
			 * "allow-query" ACL.  Remember this so we
			 * don't have to check again.
			 */
			client->query.attributes |= NS_QUERYATTR_QUERYOK;
		}
		/*
		 * We've now evaluated the view's query ACL, and
		 * the NS_QUERYATTR_QUERYOK attribute is now valid.
		 */
		client->query.attributes |= NS_QUERYATTR_QUERYOKVALID;
	}

	dbversion->acl_checked = ISC_TRUE;
	if (result != ISC_R_SUCCESS) {
		dbversion->queryok = ISC_FALSE;
		return (DNS_R_REFUSED);
	}
	dbversion->queryok = ISC_TRUE;

 approved:
	/* Transfer ownership, if necessary. */
	if (versionp != NULL)
		*versionp = dbversion->version;
	return (ISC_R_SUCCESS);
}

static inline isc_result_t
query_getzonedb(ns_client_t *client, dns_name_t *name, dns_rdatatype_t qtype,
		unsigned int options, dns_zone_t **zonep, dns_db_t **dbp,
		dns_dbversion_t **versionp)
{
	isc_result_t result;
	unsigned int ztoptions;
	dns_zone_t *zone = NULL;
	dns_db_t *db = NULL;
	isc_boolean_t partial = ISC_FALSE;

	REQUIRE(zonep != NULL && *zonep == NULL);
	REQUIRE(dbp != NULL && *dbp == NULL);

	/*%
	 * Find a zone database to answer the query.
	 */
	ztoptions = ((options & DNS_GETDB_NOEXACT) != 0) ?
		DNS_ZTFIND_NOEXACT : 0;

	result = dns_zt_find(client->view->zonetable, name, ztoptions, NULL,
			     &zone);
	if (result == DNS_R_PARTIALMATCH)
		partial = ISC_TRUE;
	if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
		result = dns_zone_getdb(zone, &db);

	if (result != ISC_R_SUCCESS)
		goto fail;

	result = query_validatezonedb(client, name, qtype, options, zone, db,
				      versionp);

	if (result != ISC_R_SUCCESS)
		goto fail;

	/* Transfer ownership. */
	*zonep = zone;
	*dbp = db;

	if (partial && (options & DNS_GETDB_PARTIAL) != 0)
		return (DNS_R_PARTIALMATCH);
	return (ISC_R_SUCCESS);

 fail:
	if (zone != NULL)
		dns_zone_detach(&zone);
	if (db != NULL)
		dns_db_detach(&db);

	return (result);
}

static void
rpz_log_rewrite(ns_client_t *client, const char *disabled,
		dns_rpz_policy_t policy, dns_rpz_type_t type,
		dns_name_t *rpz_qname) {
	char qname_buf[DNS_NAME_FORMATSIZE];
	char rpz_qname_buf[DNS_NAME_FORMATSIZE];

	if (!isc_log_wouldlog(ns_g_lctx, DNS_RPZ_INFO_LEVEL))
		return;

	dns_name_format(client->query.qname, qname_buf, sizeof(qname_buf));
	dns_name_format(rpz_qname, rpz_qname_buf, sizeof(rpz_qname_buf));

	ns_client_log(client, DNS_LOGCATEGORY_RPZ, NS_LOGMODULE_QUERY,
		      DNS_RPZ_INFO_LEVEL, "%srpz %s %s rewrite %s via %s",
		      disabled,
		      dns_rpz_type2str(type), dns_rpz_policy2str(policy),
		      qname_buf, rpz_qname_buf);
}

static void
rpz_log_fail(ns_client_t *client, int level,
	     dns_rpz_type_t rpz_type, dns_name_t *name,
	     const char *str, isc_result_t result)
{
	char namebuf1[DNS_NAME_FORMATSIZE];
	char namebuf2[DNS_NAME_FORMATSIZE];

	if (!isc_log_wouldlog(ns_g_lctx, level))
		return;

	dns_name_format(client->query.qname, namebuf1, sizeof(namebuf1));
	dns_name_format(name, namebuf2, sizeof(namebuf2));
	ns_client_log(client, NS_LOGCATEGORY_QUERY_EERRORS,
		      NS_LOGMODULE_QUERY, level,
		      "rpz %s rewrite %s via %s %sfailed: %s",
		      dns_rpz_type2str(rpz_type),
		      namebuf1, namebuf2, str, isc_result_totext(result));
}

/*
 * Get a policy rewrite zone database.
 */
static isc_result_t
rpz_getdb(ns_client_t *client, dns_rpz_type_t rpz_type, dns_name_t *rpz_qname,
	  dns_zone_t **zonep, dns_db_t **dbp, dns_dbversion_t **versionp)
{
	char namebuf1[DNS_NAME_FORMATSIZE];
	char namebuf2[DNS_NAME_FORMATSIZE];
	dns_dbversion_t *rpz_version = NULL;
	isc_result_t result;

	result = query_getzonedb(client, rpz_qname, dns_rdatatype_any,
				 DNS_GETDB_IGNOREACL, zonep, dbp, &rpz_version);
	if (result == ISC_R_SUCCESS) {
		if (isc_log_wouldlog(ns_g_lctx, DNS_RPZ_DEBUG_LEVEL2)) {
			dns_name_format(client->query.qname, namebuf1,
					sizeof(namebuf1));
			dns_name_format(rpz_qname, namebuf2, sizeof(namebuf2));
			ns_client_log(client, DNS_LOGCATEGORY_RPZ,
				      NS_LOGMODULE_QUERY, DNS_RPZ_DEBUG_LEVEL2,
				      "try rpz %s rewrite %s via %s",
				      dns_rpz_type2str(rpz_type),
				      namebuf1, namebuf2);
		}
		*versionp = rpz_version;
		return (ISC_R_SUCCESS);
	}
	rpz_log_fail(client, DNS_RPZ_ERROR_LEVEL, rpz_type, rpz_qname,
		     "query_getzonedb() ", result);
	return (result);
}

static inline isc_result_t
query_getcachedb(ns_client_t *client, dns_name_t *name, dns_rdatatype_t qtype,
		 dns_db_t **dbp, unsigned int options)
{
	isc_result_t result;
	isc_boolean_t check_acl;
	dns_db_t *db = NULL;

	REQUIRE(dbp != NULL && *dbp == NULL);

	/*%
	 * Find a cache database to answer the query.
	 * This may fail with DNS_R_REFUSED if the client
	 * is not allowed to use the cache.
	 */

	if (!USECACHE(client))
		return (DNS_R_REFUSED);
	dns_db_attach(client->view->cachedb, &db);

	if ((client->query.attributes & NS_QUERYATTR_CACHEACLOKVALID) != 0) {
		/*
		 * We've evaluated the view's cacheacl already.  If
		 * NS_QUERYATTR_CACHEACLOK is set, then the client is
		 * allowed to make queries, otherwise the query should
		 * be refused.
		 */
		check_acl = ISC_FALSE;
		if ((client->query.attributes & NS_QUERYATTR_CACHEACLOK) == 0)
			goto refuse;
	} else {
		/*
		 * We haven't evaluated the view's queryacl yet.
		 */
		check_acl = ISC_TRUE;
	}

	if (check_acl) {
		isc_boolean_t log = ISC_TF((options & DNS_GETDB_NOLOG) == 0);
		char msg[NS_CLIENT_ACLMSGSIZE("query (cache)")];

		result = ns_client_checkaclsilent(client, NULL,
						  client->view->cacheacl,
						  ISC_TRUE);
		if (result == ISC_R_SUCCESS) {
			/*
			 * We were allowed by the "allow-query-cache" ACL.
			 * Remember this so we don't have to check again.
			 */
			client->query.attributes |=
				NS_QUERYATTR_CACHEACLOK;
			if (log && isc_log_wouldlog(ns_g_lctx,
						     ISC_LOG_DEBUG(3)))
			{
				ns_client_aclmsg("query (cache)", name, qtype,
						 client->view->rdclass,
						 msg, sizeof(msg));
				ns_client_log(client,
					      DNS_LOGCATEGORY_SECURITY,
					      NS_LOGMODULE_QUERY,
					      ISC_LOG_DEBUG(3),
					      "%s approved", msg);
			}
		} else if (log) {
			ns_client_aclmsg("query (cache)", name, qtype,
					 client->view->rdclass, msg,
					 sizeof(msg));
			ns_client_log(client, DNS_LOGCATEGORY_SECURITY,
				      NS_LOGMODULE_QUERY, ISC_LOG_INFO,
				      "%s denied", msg);
		}
		/*
		 * We've now evaluated the view's query ACL, and
		 * the NS_QUERYATTR_CACHEACLOKVALID attribute is now valid.
		 */
		client->query.attributes |= NS_QUERYATTR_CACHEACLOKVALID;

		if (result != ISC_R_SUCCESS)
			goto refuse;
	}

	/* Approved. */

	/* Transfer ownership. */
	*dbp = db;

	return (ISC_R_SUCCESS);

 refuse:
	result = DNS_R_REFUSED;

	if (db != NULL)
		dns_db_detach(&db);

	return (result);
}


static inline isc_result_t
query_getdb(ns_client_t *client, dns_name_t *name, dns_rdatatype_t qtype,
	    unsigned int options, dns_zone_t **zonep, dns_db_t **dbp,
	    dns_dbversion_t **versionp, isc_boolean_t *is_zonep)
{
	isc_result_t result;

	isc_result_t tresult;
	unsigned int namelabels;
	unsigned int zonelabels;
	dns_zone_t *zone = NULL;
	dns_db_t *tdbp;

	REQUIRE(zonep != NULL && *zonep == NULL);

	tdbp = NULL;

	/* Calculate how many labels are in name. */
	namelabels = dns_name_countlabels(name);
	zonelabels = 0;

	/* Try to find name in bind's standard database. */
	result = query_getzonedb(client, name, qtype, options, &zone,
				 dbp, versionp);

	/* See how many labels are in the zone's name.	  */
	if (result == ISC_R_SUCCESS && zone != NULL)
		zonelabels = dns_name_countlabels(dns_zone_getorigin(zone));
	/*
	 * If # zone labels < # name labels, try to find an even better match
	 * Only try if a DLZ driver is loaded for this view
	 */
	if (zonelabels < namelabels && client->view->dlzdatabase != NULL) {
		tresult = dns_dlzfindzone(client->view, name,
					  zonelabels, &tdbp);
		 /* If we successful, we found a better match. */
		if (tresult == ISC_R_SUCCESS) {
			/*
			 * If the previous search returned a zone, detach it.
			 */
			if (zone != NULL)
				dns_zone_detach(&zone);

			/*
			 * If the previous search returned a database,
			 * detach it.
			 */
			if (*dbp != NULL)
				dns_db_detach(dbp);

			/*
			 * If the previous search returned a version, clear it.
			 */
			*versionp = NULL;

			/*
			 * Get our database version.
			 */
			dns_db_currentversion(tdbp, versionp);

			/*
			 * Be sure to return our database.
			 */
			*dbp = tdbp;

			/*
			 * We return a null zone, No stats for DLZ zones.
			 */
			zone = NULL;
			result = tresult;
		}
	}

	/* If successful, Transfer ownership of zone. */
	if (result == ISC_R_SUCCESS) {
		*zonep = zone;
		/*
		 * If neither attempt above succeeded, return the cache instead
		 */
		*is_zonep = ISC_TRUE;
	} else if (result == ISC_R_NOTFOUND) {
		result = query_getcachedb(client, name, qtype, dbp, options);
		*is_zonep = ISC_FALSE;
	}
	return (result);
}

static inline isc_boolean_t
query_isduplicate(ns_client_t *client, dns_name_t *name,
		  dns_rdatatype_t type, dns_name_t **mnamep)
{
	dns_section_t section;
	dns_name_t *mname = NULL;
	isc_result_t result;

	CTRACE("query_isduplicate");

	for (section = DNS_SECTION_ANSWER;
	     section <= DNS_SECTION_ADDITIONAL;
	     section++) {
		result = dns_message_findname(client->message, section,
					      name, type, 0, &mname, NULL);
		if (result == ISC_R_SUCCESS) {
			/*
			 * We've already got this RRset in the response.
			 */
			CTRACE("query_isduplicate: true: done");
			return (ISC_TRUE);
		} else if (result == DNS_R_NXRRSET) {
			/*
			 * The name exists, but the rdataset does not.
			 */
			if (section == DNS_SECTION_ADDITIONAL)
				break;
		} else
			RUNTIME_CHECK(result == DNS_R_NXDOMAIN);
		mname = NULL;
	}

	if (mnamep != NULL)
		*mnamep = mname;

	CTRACE("query_isduplicate: false: done");
	return (ISC_FALSE);
}

static isc_result_t
query_addadditional(void *arg, dns_name_t *name, dns_rdatatype_t qtype) {
	ns_client_t *client = arg;
	isc_result_t result, eresult;
	dns_dbnode_t *node;
	dns_db_t *db;
	dns_name_t *fname, *mname;
	dns_rdataset_t *rdataset, *sigrdataset, *trdataset;
	isc_buffer_t *dbuf;
	isc_buffer_t b;
	dns_dbversion_t *version;
	isc_boolean_t added_something, need_addname;
	dns_zone_t *zone;
	dns_rdatatype_t type;

	REQUIRE(NS_CLIENT_VALID(client));
	REQUIRE(qtype != dns_rdatatype_any);

	if (!WANTDNSSEC(client) && dns_rdatatype_isdnssec(qtype))
		return (ISC_R_SUCCESS);

	CTRACE("query_addadditional");

	/*
	 * Initialization.
	 */
	eresult = ISC_R_SUCCESS;
	fname = NULL;
	rdataset = NULL;
	sigrdataset = NULL;
	trdataset = NULL;
	db = NULL;
	version = NULL;
	node = NULL;
	added_something = ISC_FALSE;
	need_addname = ISC_FALSE;
	zone = NULL;

	/*
	 * We treat type A additional section processing as if it
	 * were "any address type" additional section processing.
	 * To avoid multiple lookups, we do an 'any' database
	 * lookup and iterate over the node.
	 */
	if (qtype == dns_rdatatype_a)
		type = dns_rdatatype_any;
	else
		type = qtype;

	/*
	 * Get some resources.
	 */
	dbuf = query_getnamebuf(client);
	if (dbuf == NULL)
		goto cleanup;
	fname = query_newname(client, dbuf, &b);
	rdataset = query_newrdataset(client);
	if (fname == NULL || rdataset == NULL)
		goto cleanup;
	if (WANTDNSSEC(client)) {
		sigrdataset = query_newrdataset(client);
		if (sigrdataset == NULL)
			goto cleanup;
	}

	/*
	 * Look for a zone database that might contain authoritative
	 * additional data.
	 */
	result = query_getzonedb(client, name, qtype, DNS_GETDB_NOLOG,
				 &zone, &db, &version);
	if (result != ISC_R_SUCCESS)
		goto try_cache;

	CTRACE("query_addadditional: db_find");

	/*
	 * Since we are looking for authoritative data, we do not set
	 * the GLUEOK flag.  Glue will be looked for later, but not
	 * necessarily in the same database.
	 */
	node = NULL;
	result = dns_db_find(db, name, version, type, client->query.dboptions,
			     client->now, &node, fname, rdataset,
			     sigrdataset);
	if (result == ISC_R_SUCCESS) {
		if (sigrdataset != NULL && !dns_db_issecure(db) &&
		    dns_rdataset_isassociated(sigrdataset))
			dns_rdataset_disassociate(sigrdataset);
		goto found;
	}

	if (dns_rdataset_isassociated(rdataset))
		dns_rdataset_disassociate(rdataset);
	if (sigrdataset != NULL && dns_rdataset_isassociated(sigrdataset))
		dns_rdataset_disassociate(sigrdataset);
	if (node != NULL)
		dns_db_detachnode(db, &node);
	version = NULL;
	dns_db_detach(&db);

	/*
	 * No authoritative data was found.  The cache is our next best bet.
	 */

 try_cache:
	result = query_getcachedb(client, name, qtype, &db, DNS_GETDB_NOLOG);
	if (result != ISC_R_SUCCESS)
		/*
		 * Most likely the client isn't allowed to query the cache.
		 */
		goto try_glue;
	/*
	 * Attempt to validate glue.
	 */
	if (sigrdataset == NULL) {
		sigrdataset = query_newrdataset(client);
		if (sigrdataset == NULL)
			goto cleanup;
	}
	result = dns_db_find(db, name, version, type,
			     client->query.dboptions |
			     DNS_DBFIND_GLUEOK | DNS_DBFIND_ADDITIONALOK,
			     client->now, &node, fname, rdataset,
			     sigrdataset);
	if (result == DNS_R_GLUE &&
	    validate(client, db, fname, rdataset, sigrdataset))
		result = ISC_R_SUCCESS;
	if (!WANTDNSSEC(client))
		query_putrdataset(client, &sigrdataset);
	if (result == ISC_R_SUCCESS)
		goto found;

	if (dns_rdataset_isassociated(rdataset))
		dns_rdataset_disassociate(rdataset);
	if (sigrdataset != NULL && dns_rdataset_isassociated(sigrdataset))
		dns_rdataset_disassociate(sigrdataset);
	if (node != NULL)
		dns_db_detachnode(db, &node);
	dns_db_detach(&db);

 try_glue:
	/*
	 * No cached data was found.  Glue is our last chance.
	 * RFC1035 sayeth:
	 *
	 *	NS records cause both the usual additional section
	 *	processing to locate a type A record, and, when used
	 *	in a referral, a special search of the zone in which
	 *	they reside for glue information.
	 *
	 * This is the "special search".  Note that we must search
	 * the zone where the NS record resides, not the zone it
	 * points to, and that we only do the search in the delegation
	 * case (identified by client->query.gluedb being set).
	 */

	if (client->query.gluedb == NULL)
		goto cleanup;

	/*
	 * Don't poison caches using the bailiwick protection model.
	 */
	if (!dns_name_issubdomain(name, dns_db_origin(client->query.gluedb)))
		goto cleanup;

	dns_db_attach(client->query.gluedb, &db);
	result = dns_db_find(db, name, version, type,
			     client->query.dboptions | DNS_DBFIND_GLUEOK,
			     client->now, &node, fname, rdataset,
			     sigrdataset);
	if (!(result == ISC_R_SUCCESS ||
	      result == DNS_R_ZONECUT ||
	      result == DNS_R_GLUE))
		goto cleanup;

 found:
	/*
	 * We have found a potential additional data rdataset, or
	 * at least a node to iterate over.
	 */
	query_keepname(client, fname, dbuf);

	/*
	 * If we have an rdataset, add it to the additional data
	 * section.
	 */
	mname = NULL;
	if (dns_rdataset_isassociated(rdataset) &&
	    !query_isduplicate(client, fname, type, &mname)) {
		if (mname != NULL) {
			INSIST(mname != fname);
			query_releasename(client, &fname);
			fname = mname;
		} else
			need_addname = ISC_TRUE;
		ISC_LIST_APPEND(fname->list, rdataset, link);
		trdataset = rdataset;
		rdataset = NULL;
		added_something = ISC_TRUE;
		/*
		 * Note: we only add SIGs if we've added the type they cover,
		 * so we do not need to check if the SIG rdataset is already
		 * in the response.
		 */
		if (sigrdataset != NULL &&
		    dns_rdataset_isassociated(sigrdataset))
		{
			ISC_LIST_APPEND(fname->list, sigrdataset, link);
			sigrdataset = NULL;
		}
	}

	if (qtype == dns_rdatatype_a) {
#ifdef ALLOW_FILTER_AAAA_ON_V4
		isc_boolean_t have_a = ISC_FALSE;
#endif

		/*
		 * We now go looking for A and AAAA records, along with
		 * their signatures.
		 *
		 * XXXRTH  This code could be more efficient.
		 */
		if (rdataset != NULL) {
			if (dns_rdataset_isassociated(rdataset))
				dns_rdataset_disassociate(rdataset);
		} else {
			rdataset = query_newrdataset(client);
			if (rdataset == NULL)
				goto addname;
		}
		if (sigrdataset != NULL) {
			if (dns_rdataset_isassociated(sigrdataset))
				dns_rdataset_disassociate(sigrdataset);
		} else if (WANTDNSSEC(client)) {
			sigrdataset = query_newrdataset(client);
			if (sigrdataset == NULL)
				goto addname;
		}
		if (query_isduplicate(client, fname, dns_rdatatype_a, NULL))
			goto aaaa_lookup;
		result = dns_db_findrdataset(db, node, version,
					     dns_rdatatype_a, 0,
					     client->now, rdataset,
					     sigrdataset);
		if (result == DNS_R_NCACHENXDOMAIN)
			goto addname;
		if (result == DNS_R_NCACHENXRRSET) {
			dns_rdataset_disassociate(rdataset);
			if (sigrdataset != NULL &&
			    dns_rdataset_isassociated(sigrdataset))
				dns_rdataset_disassociate(sigrdataset);
		}
		if (result == ISC_R_SUCCESS) {
			mname = NULL;
#ifdef ALLOW_FILTER_AAAA_ON_V4
			have_a = ISC_TRUE;
#endif
			if (!query_isduplicate(client, fname,
					       dns_rdatatype_a, &mname)) {
				if (mname != fname) {
					if (mname != NULL) {
						query_releasename(client, &fname);
						fname = mname;
					} else
						need_addname = ISC_TRUE;
				}
				ISC_LIST_APPEND(fname->list, rdataset, link);
				added_something = ISC_TRUE;
				if (sigrdataset != NULL &&
				    dns_rdataset_isassociated(sigrdataset))
				{
					ISC_LIST_APPEND(fname->list,
							sigrdataset, link);
					sigrdataset =
						query_newrdataset(client);
				}
				rdataset = query_newrdataset(client);
				if (rdataset == NULL)
					goto addname;
				if (WANTDNSSEC(client) && sigrdataset == NULL)
					goto addname;
			} else {
				dns_rdataset_disassociate(rdataset);
				if (sigrdataset != NULL &&
				    dns_rdataset_isassociated(sigrdataset))
					dns_rdataset_disassociate(sigrdataset);
			}
		}
  aaaa_lookup:
		if (query_isduplicate(client, fname, dns_rdatatype_aaaa, NULL))
			goto addname;
		result = dns_db_findrdataset(db, node, version,
					     dns_rdatatype_aaaa, 0,
					     client->now, rdataset,
					     sigrdataset);
		if (result == DNS_R_NCACHENXDOMAIN)
			goto addname;
		if (result == DNS_R_NCACHENXRRSET) {
			dns_rdataset_disassociate(rdataset);
			if (sigrdataset != NULL &&
			    dns_rdataset_isassociated(sigrdataset))
				dns_rdataset_disassociate(sigrdataset);
		}
		if (result == ISC_R_SUCCESS) {
			mname = NULL;
			/*
			 * There's an A; check whether we're filtering AAAA
			 */
#ifdef ALLOW_FILTER_AAAA_ON_V4
			if (have_a &&
			    (client->filter_aaaa == dns_v4_aaaa_break_dnssec ||
			    (client->filter_aaaa == dns_v4_aaaa_filter &&
			     (!WANTDNSSEC(client) || sigrdataset == NULL ||
			      !dns_rdataset_isassociated(sigrdataset)))))
				goto addname;
#endif
			if (!query_isduplicate(client, fname,
					       dns_rdatatype_aaaa, &mname)) {
				if (mname != fname) {
					if (mname != NULL) {
						query_releasename(client, &fname);
						fname = mname;
					} else
						need_addname = ISC_TRUE;
				}
				ISC_LIST_APPEND(fname->list, rdataset, link);
				added_something = ISC_TRUE;
				if (sigrdataset != NULL &&
				    dns_rdataset_isassociated(sigrdataset))
				{
					ISC_LIST_APPEND(fname->list,
							sigrdataset, link);
					sigrdataset = NULL;
				}
				rdataset = NULL;
			}
		}
	}

 addname:
	CTRACE("query_addadditional: addname");
	/*
	 * If we haven't added anything, then we're done.
	 */
	if (!added_something)
		goto cleanup;

	/*
	 * We may have added our rdatasets to an existing name, if so, then
	 * need_addname will be ISC_FALSE.  Whether we used an existing name
	 * or a new one, we must set fname to NULL to prevent cleanup.
	 */
	if (need_addname)
		dns_message_addname(client->message, fname,
				    DNS_SECTION_ADDITIONAL);
	fname = NULL;

	/*
	 * In a few cases, we want to add additional data for additional
	 * data.  It's simpler to just deal with special cases here than
	 * to try to create a general purpose mechanism and allow the
	 * rdata implementations to do it themselves.
	 *
	 * This involves recursion, but the depth is limited.  The
	 * most complex case is adding a SRV rdataset, which involves
	 * recursing to add address records, which in turn can cause
	 * recursion to add KEYs.
	 */
	if (type == dns_rdatatype_srv && trdataset != NULL) {
		/*
		 * If we're adding SRV records to the additional data
		 * section, it's helpful if we add the SRV additional data
		 * as well.
		 */
		eresult = dns_rdataset_additionaldata(trdataset,
						      query_addadditional,
						      client);
	}

 cleanup:
	CTRACE("query_addadditional: cleanup");
	query_putrdataset(client, &rdataset);
	if (sigrdataset != NULL)
		query_putrdataset(client, &sigrdataset);
	if (fname != NULL)
		query_releasename(client, &fname);
	if (node != NULL)
		dns_db_detachnode(db, &node);
	if (db != NULL)
		dns_db_detach(&db);
	if (zone != NULL)
		dns_zone_detach(&zone);

	CTRACE("query_addadditional: done");
	return (eresult);
}

static inline void
query_discardcache(ns_client_t *client, dns_rdataset_t *rdataset_base,
		   dns_rdatasetadditional_t additionaltype,
		   dns_rdatatype_t type, dns_zone_t **zonep, dns_db_t **dbp,
		   dns_dbversion_t **versionp, dns_dbnode_t **nodep,
		   dns_name_t *fname)
{
	dns_rdataset_t *rdataset;

	while  ((rdataset = ISC_LIST_HEAD(fname->list)) != NULL) {
		ISC_LIST_UNLINK(fname->list, rdataset, link);
		query_putrdataset(client, &rdataset);
	}
	if (*versionp != NULL)
		dns_db_closeversion(*dbp, versionp, ISC_FALSE);
	if (*nodep != NULL)
		dns_db_detachnode(*dbp, nodep);
	if (*dbp != NULL)
		dns_db_detach(dbp);
	if (*zonep != NULL)
		dns_zone_detach(zonep);
	(void)dns_rdataset_putadditional(client->view->acache, rdataset_base,
					 additionaltype, type);
}

static inline isc_result_t
query_iscachevalid(dns_zone_t *zone, dns_db_t *db, dns_db_t *db0,
		   dns_dbversion_t *version)
{
	isc_result_t result = ISC_R_SUCCESS;
	dns_dbversion_t *version_current = NULL;
	dns_db_t *db_current = db0;

	if (db_current == NULL) {
		result = dns_zone_getdb(zone, &db_current);
		if (result != ISC_R_SUCCESS)
			return (result);
	}
	dns_db_currentversion(db_current, &version_current);
	if (db_current != db || version_current != version) {
		result = ISC_R_FAILURE;
		goto cleanup;
	}

 cleanup:
	dns_db_closeversion(db_current, &version_current, ISC_FALSE);
	if (db0 == NULL && db_current != NULL)
		dns_db_detach(&db_current);

	return (result);
}

static isc_result_t
query_addadditional2(void *arg, dns_name_t *name, dns_rdatatype_t qtype) {
	client_additionalctx_t *additionalctx = arg;
	dns_rdataset_t *rdataset_base;
	ns_client_t *client;
	isc_result_t result, eresult;
	dns_dbnode_t *node, *cnode;
	dns_db_t *db, *cdb;
	dns_name_t *fname, *mname0, cfname;
	dns_rdataset_t *rdataset, *sigrdataset;
	dns_rdataset_t *crdataset, *crdataset_next;
	isc_buffer_t *dbuf;
	isc_buffer_t b;
	dns_dbversion_t *version, *cversion;
	isc_boolean_t added_something, need_addname, needadditionalcache;
	isc_boolean_t need_sigrrset;
	dns_zone_t *zone;
	dns_rdatatype_t type;
	dns_rdatasetadditional_t additionaltype;

	/*
	 * If we don't have an additional cache call query_addadditional.
	 */
	client = additionalctx->client;
	REQUIRE(NS_CLIENT_VALID(client));

	if (qtype != dns_rdatatype_a || client->view->acache == NULL) {
		/*
		 * This function is optimized for "address" types.  For other
		 * types, use a generic routine.
		 * XXX: ideally, this function should be generic enough.
		 */
		return (query_addadditional(additionalctx->client,
					    name, qtype));
	}

	/*
	 * Initialization.
	 */
	rdataset_base = additionalctx->rdataset;
	eresult = ISC_R_SUCCESS;
	fname = NULL;
	rdataset = NULL;
	sigrdataset = NULL;
	db = NULL;
	cdb = NULL;
	version = NULL;
	cversion = NULL;
	node = NULL;
	cnode = NULL;
	added_something = ISC_FALSE;
	need_addname = ISC_FALSE;
	zone = NULL;
	needadditionalcache = ISC_FALSE;
	POST(needadditionalcache);
	additionaltype = dns_rdatasetadditional_fromauth;
	dns_name_init(&cfname, NULL);

	CTRACE("query_addadditional2");

	/*
	 * We treat type A additional section processing as if it
	 * were "any address type" additional section processing.
	 * To avoid multiple lookups, we do an 'any' database
	 * lookup and iterate over the node.
	 * XXXJT: this approach can cause a suboptimal result when the cache
	 * DB only has partial address types and the glue DB has remaining
	 * ones.
	 */
	type = dns_rdatatype_any;

	/*
	 * Get some resources.
	 */
	dbuf = query_getnamebuf(client);
	if (dbuf == NULL)
		goto cleanup;
	fname = query_newname(client, dbuf, &b);
	if (fname == NULL)
		goto cleanup;
	dns_name_setbuffer(&cfname, &b); /* share the buffer */

	/* Check additional cache */
	result = dns_rdataset_getadditional(rdataset_base, additionaltype,
					    type, client->view->acache, &zone,
					    &cdb, &cversion, &cnode, &cfname,
					    client->message, client->now);
	if (result != ISC_R_SUCCESS)
		goto findauthdb;
	if (zone == NULL) {
		CTRACE("query_addadditional2: auth zone not found");
		goto try_cache;
	}

	/* Is the cached DB up-to-date? */
	result = query_iscachevalid(zone, cdb, NULL, cversion);
	if (result != ISC_R_SUCCESS) {
		CTRACE("query_addadditional2: old auth additional cache");
		query_discardcache(client, rdataset_base, additionaltype,
				   type, &zone, &cdb, &cversion, &cnode,
				   &cfname);
		goto findauthdb;
	}

	if (cnode == NULL) {
		/*
		 * We have a negative cache.  We don't have to check the zone
		 * ACL, since the result (not using this zone) would be same
		 * regardless of the result.
		 */
		CTRACE("query_addadditional2: negative auth additional cache");
		dns_db_closeversion(cdb, &cversion, ISC_FALSE);
		dns_db_detach(&cdb);
		dns_zone_detach(&zone);
		goto try_cache;
	}

	result = query_validatezonedb(client, name, qtype, DNS_GETDB_NOLOG,
				      zone, cdb, NULL);
	if (result != ISC_R_SUCCESS) {
		query_discardcache(client, rdataset_base, additionaltype,
				   type, &zone, &cdb, &cversion, &cnode,
				   &cfname);
		goto try_cache;
	}

	/* We've got an active cache. */
	CTRACE("query_addadditional2: auth additional cache");
	dns_db_closeversion(cdb, &cversion, ISC_FALSE);
	db = cdb;
	node = cnode;
	dns_name_clone(&cfname, fname);
	query_keepname(client, fname, dbuf);
	goto foundcache;

	/*
	 * Look for a zone database that might contain authoritative
	 * additional data.
	 */
 findauthdb:
	result = query_getzonedb(client, name, qtype, DNS_GETDB_NOLOG,
				 &zone, &db, &version);
	if (result != ISC_R_SUCCESS) {
		/* Cache the negative result */
		(void)dns_rdataset_setadditional(rdataset_base, additionaltype,
						 type, client->view->acache,
						 NULL, NULL, NULL, NULL,
						 NULL);
		goto try_cache;
	}

	CTRACE("query_addadditional2: db_find");

	/*
	 * Since we are looking for authoritative data, we do not set
	 * the GLUEOK flag.  Glue will be looked for later, but not
	 * necessarily in the same database.
	 */
	node = NULL;
	result = dns_db_find(db, name, version, type, client->query.dboptions,
			     client->now, &node, fname, NULL, NULL);
	if (result == ISC_R_SUCCESS)
		goto found;

	/* Cache the negative result */
	(void)dns_rdataset_setadditional(rdataset_base, additionaltype,
					 type, client->view->acache, zone, db,
					 version, NULL, fname);

	if (node != NULL)
		dns_db_detachnode(db, &node);
	version = NULL;
	dns_db_detach(&db);

	/*
	 * No authoritative data was found.  The cache is our next best bet.
	 */

 try_cache:
	additionaltype = dns_rdatasetadditional_fromcache;
	result = query_getcachedb(client, name, qtype, &db, DNS_GETDB_NOLOG);
	if (result != ISC_R_SUCCESS)
		/*
		 * Most likely the client isn't allowed to query the cache.
		 */
		goto try_glue;

	result = dns_db_find(db, name, version, type,
			     client->query.dboptions |
			     DNS_DBFIND_GLUEOK | DNS_DBFIND_ADDITIONALOK,
			     client->now, &node, fname, NULL, NULL);
	if (result == ISC_R_SUCCESS)
		goto found;

	if (node != NULL)
		dns_db_detachnode(db, &node);
	dns_db_detach(&db);

 try_glue:
	/*
	 * No cached data was found.  Glue is our last chance.
	 * RFC1035 sayeth:
	 *
	 *	NS records cause both the usual additional section
	 *	processing to locate a type A record, and, when used
	 *	in a referral, a special search of the zone in which
	 *	they reside for glue information.
	 *
	 * This is the "special search".  Note that we must search
	 * the zone where the NS record resides, not the zone it
	 * points to, and that we only do the search in the delegation
	 * case (identified by client->query.gluedb being set).
	 */
	if (client->query.gluedb == NULL)
		goto cleanup;

	/*
	 * Don't poison caches using the bailiwick protection model.
	 */
	if (!dns_name_issubdomain(name, dns_db_origin(client->query.gluedb)))
		goto cleanup;

	/* Check additional cache */
	additionaltype = dns_rdatasetadditional_fromglue;
	result = dns_rdataset_getadditional(rdataset_base, additionaltype,
					    type, client->view->acache, NULL,
					    &cdb, &cversion, &cnode, &cfname,
					    client->message, client->now);
	if (result != ISC_R_SUCCESS)
		goto findglue;

	result = query_iscachevalid(zone, cdb, client->query.gluedb, cversion);
	if (result != ISC_R_SUCCESS) {
		CTRACE("query_addadditional2: old glue additional cache");
		query_discardcache(client, rdataset_base, additionaltype,
				   type, &zone, &cdb, &cversion, &cnode,
				   &cfname);
		goto findglue;
	}

	if (cnode == NULL) {
		/* We have a negative cache. */
		CTRACE("query_addadditional2: negative glue additional cache");
		dns_db_closeversi…