/*
 * Copyright (C) 2004-2012  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000-2003  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.
 */

/* $Id$ */

#include <config.h>

#include <isc/base32.h>
#include <isc/mem.h>
#include <isc/print.h>
#include <isc/sha2.h>
#include <isc/string.h>
#include <isc/task.h>
#include <isc/util.h>

#include <dns/db.h>
#include <dns/dnssec.h>
#include <dns/ds.h>
#include <dns/events.h>
#include <dns/keytable.h>
#include <dns/keyvalues.h>
#include <dns/log.h>
#include <dns/message.h>
#include <dns/ncache.h>
#include <dns/nsec.h>
#include <dns/nsec3.h>
#include <dns/rdata.h>
#include <dns/rdataset.h>
#include <dns/rdatatype.h>
#include <dns/resolver.h>
#include <dns/result.h>
#include <dns/validator.h>
#include <dns/view.h>

/*! \file
 * \brief
 * Basic processing sequences.
 *
 * \li When called with rdataset and sigrdataset:
 * validator_start -> validate -> proveunsecure -> startfinddlvsep ->
 *	dlv_validator_start -> validator_start -> validate -> proveunsecure
 *
 * validator_start -> validate -> nsecvalidate	(secure wildcard answer)
 *
 * \li When called with rdataset, sigrdataset and with DNS_VALIDATOR_DLV:
 * validator_start -> startfinddlvsep -> dlv_validator_start ->
 *	validator_start -> validate -> proveunsecure
 *
 * \li When called with rdataset:
 * validator_start -> proveunsecure -> startfinddlvsep ->
 *	dlv_validator_start -> validator_start -> proveunsecure
 *
 * \li When called with rdataset and with DNS_VALIDATOR_DLV:
 * validator_start -> startfinddlvsep -> dlv_validator_start ->
 *	validator_start -> proveunsecure
 *
 * \li When called without a rdataset:
 * validator_start -> nsecvalidate -> proveunsecure -> startfinddlvsep ->
 *	dlv_validator_start -> validator_start -> nsecvalidate -> proveunsecure
 *
 * Note: there isn't a case for DNS_VALIDATOR_DLV here as we want nsecvalidate()
 * to always validate the authority section even when it does not contain
 * signatures.
 *
 * validator_start: determines what type of validation to do.
 * validate: attempts to perform a positive validation.
 * proveunsecure: attempts to prove the answer comes from a unsecure zone.
 * nsecvalidate: attempts to prove a negative response.
 * startfinddlvsep: starts the DLV record lookup.
 * dlv_validator_start: resets state and restarts the lookup using the
 *	DLV RRset found by startfinddlvsep.
 */

#define VALIDATOR_MAGIC			ISC_MAGIC('V', 'a', 'l', '?')
#define VALID_VALIDATOR(v)		ISC_MAGIC_VALID(v, VALIDATOR_MAGIC)

#define VALATTR_SHUTDOWN		0x0001	/*%< Shutting down. */
#define VALATTR_CANCELED		0x0002	/*%< Canceled. */
#define VALATTR_TRIEDVERIFY		0x0004  /*%< We have found a key and
						 * have attempted a verify. */
#define VALATTR_INSECURITY		0x0010	/*%< Attempting proveunsecure. */
#define VALATTR_DLVTRIED		0x0020	/*%< Looked for a DLV record. */

/*!
 * NSEC proofs to be looked for.
 */
#define VALATTR_NEEDNOQNAME		0x00000100
#define VALATTR_NEEDNOWILDCARD		0x00000200
#define VALATTR_NEEDNODATA		0x00000400

/*!
 * NSEC proofs that have been found.
 */
#define VALATTR_FOUNDNOQNAME		0x00001000
#define VALATTR_FOUNDNOWILDCARD		0x00002000
#define VALATTR_FOUNDNODATA		0x00004000
#define VALATTR_FOUNDCLOSEST		0x00008000

/*
 *
 */
#define VALATTR_FOUNDOPTOUT		0x00010000
#define VALATTR_FOUNDUNKNOWN		0x00020000

#define NEEDNODATA(val) ((val->attributes & VALATTR_NEEDNODATA) != 0)
#define NEEDNOQNAME(val) ((val->attributes & VALATTR_NEEDNOQNAME) != 0)
#define NEEDNOWILDCARD(val) ((val->attributes & VALATTR_NEEDNOWILDCARD) != 0)
#define DLVTRIED(val) ((val->attributes & VALATTR_DLVTRIED) != 0)
#define FOUNDNODATA(val) ((val->attributes & VALATTR_FOUNDNODATA) != 0)
#define FOUNDNOQNAME(val) ((val->attributes & VALATTR_FOUNDNOQNAME) != 0)
#define FOUNDNOWILDCARD(val) ((val->attributes & VALATTR_FOUNDNOWILDCARD) != 0)
#define FOUNDCLOSEST(val) ((val->attributes & VALATTR_FOUNDCLOSEST) != 0)
#define FOUNDOPTOUT(val) ((val->attributes & VALATTR_FOUNDOPTOUT) != 0)

#define SHUTDOWN(v)		(((v)->attributes & VALATTR_SHUTDOWN) != 0)
#define CANCELED(v)		(((v)->attributes & VALATTR_CANCELED) != 0)

#define NEGATIVE(r)	(((r)->attributes & DNS_RDATASETATTR_NEGATIVE) != 0)

static void
destroy(dns_validator_t *val);

static isc_result_t
get_dst_key(dns_validator_t *val, dns_rdata_rrsig_t *siginfo,
	    dns_rdataset_t *rdataset);

static isc_result_t
validate(dns_validator_t *val, isc_boolean_t resume);

static isc_result_t
validatezonekey(dns_validator_t *val);

static isc_result_t
nsecvalidate(dns_validator_t *val, isc_boolean_t resume);

static isc_result_t
proveunsecure(dns_validator_t *val, isc_boolean_t have_ds,
	      isc_boolean_t resume);

static void
validator_logv(dns_validator_t *val, isc_logcategory_t *category,
	       isc_logmodule_t *module, int level, const char *fmt, va_list ap)
     ISC_FORMAT_PRINTF(5, 0);

static void
validator_log(dns_validator_t *val, int level, const char *fmt, ...)
     ISC_FORMAT_PRINTF(3, 4);

static void
validator_logcreate(dns_validator_t *val,
		    dns_name_t *name, dns_rdatatype_t type,
		    const char *caller, const char *operation);

static isc_result_t
dlv_validatezonekey(dns_validator_t *val);

static void
dlv_validator_start(dns_validator_t *val);

static isc_result_t
finddlvsep(dns_validator_t *val, isc_boolean_t resume);

static isc_result_t
startfinddlvsep(dns_validator_t *val, dns_name_t *unsecure);

/*%
 * Mark the RRsets as a answer.
 */
static inline void
markanswer(dns_validator_t *val, const char *where) {
	validator_log(val, ISC_LOG_DEBUG(3), "marking as answer (%s)", where);
	if (val->event->rdataset != NULL)
		dns_rdataset_settrust(val->event->rdataset, dns_trust_answer);
	if (val->event->sigrdataset != NULL)
		dns_rdataset_settrust(val->event->sigrdataset,
				      dns_trust_answer);
}

static inline void
marksecure(dns_validatorevent_t *event) {
	dns_rdataset_settrust(event->rdataset, dns_trust_secure);
	if (event->sigrdataset != NULL)
		dns_rdataset_settrust(event->sigrdataset, dns_trust_secure);
}

static void
validator_done(dns_validator_t *val, isc_result_t result) {
	isc_task_t *task;

	if (val->event == NULL)
		return;

	/*
	 * Caller must be holding the lock.
	 */

	val->event->result = result;
	task = val->event->ev_sender;
	val->event->ev_sender = val;
	val->event->ev_type = DNS_EVENT_VALIDATORDONE;
	val->event->ev_action = val->action;
	val->event->ev_arg = val->arg;
	isc_task_sendanddetach(&task, (isc_event_t **)&val->event);
}

static inline isc_boolean_t
exit_check(dns_validator_t *val) {
	/*
	 * Caller must be holding the lock.
	 */
	if (!SHUTDOWN(val))
		return (ISC_FALSE);

	INSIST(val->event == NULL);

	if (val->fetch != NULL || val->subvalidator != NULL)
		return (ISC_FALSE);

	return (ISC_TRUE);
}

/*
 * Check that we have atleast one supported algorithm in the DLV RRset.
 */
static inline isc_boolean_t
dlv_algorithm_supported(dns_validator_t *val) {
	dns_rdata_t rdata = DNS_RDATA_INIT;
	dns_rdata_dlv_t dlv;
	isc_result_t result;

	for (result = dns_rdataset_first(&val->dlv);
	     result == ISC_R_SUCCESS;
	     result = dns_rdataset_next(&val->dlv)) {
		dns_rdata_reset(&rdata);
		dns_rdataset_current(&val->dlv, &rdata);
		result = dns_rdata_tostruct(&rdata, &dlv, NULL);
		RUNTIME_CHECK(result == ISC_R_SUCCESS);

		if (!dns_resolver_algorithm_supported(val->view->resolver,
						      val->event->name,
						      dlv.algorithm))
			continue;

#ifdef HAVE_OPENSSL_GOST
		if (dlv.digest_type != DNS_DSDIGEST_SHA256 &&
		    dlv.digest_type != DNS_DSDIGEST_SHA1 &&
		    dlv.digest_type != DNS_DSDIGEST_GOST)
			continue;
#else
		if (dlv.digest_type != DNS_DSDIGEST_SHA256 &&
		    dlv.digest_type != DNS_DSDIGEST_SHA1)
			continue;
#endif


		return (ISC_TRUE);
	}
	return (ISC_FALSE);
}

/*%
 * Look in the NSEC record returned from a DS query to see if there is
 * a NS RRset at this name.  If it is found we are at a delegation point.
 */
static isc_boolean_t
isdelegation(dns_name_t *name, dns_rdataset_t *rdataset,
	     isc_result_t dbresult)
{
	dns_fixedname_t fixed;
	dns_label_t hashlabel;
	dns_name_t nsec3name;
	dns_rdata_nsec3_t nsec3;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	dns_rdataset_t set;
	int order;
	int scope;
	isc_boolean_t found;
	isc_buffer_t buffer;
	isc_result_t result;
	unsigned char hash[NSEC3_MAX_HASH_LENGTH];
	unsigned char owner[NSEC3_MAX_HASH_LENGTH];
	unsigned int length;

	REQUIRE(dbresult == DNS_R_NXRRSET || dbresult == DNS_R_NCACHENXRRSET);

	dns_rdataset_init(&set);
	if (dbresult == DNS_R_NXRRSET)
		dns_rdataset_clone(rdataset, &set);
	else {
		result = dns_ncache_getrdataset(rdataset, name,
						dns_rdatatype_nsec, &set);
		if (result == ISC_R_NOTFOUND)
			goto trynsec3;
		if (result != ISC_R_SUCCESS)
			return (ISC_FALSE);
	}

	INSIST(set.type == dns_rdatatype_nsec);

	found = ISC_FALSE;
	result = dns_rdataset_first(&set);
	if (result == ISC_R_SUCCESS) {
		dns_rdataset_current(&set, &rdata);
		found = dns_nsec_typepresent(&rdata, dns_rdatatype_ns);
		dns_rdata_reset(&rdata);
	}
	dns_rdataset_disassociate(&set);
	return (found);

 trynsec3:
	/*
	 * Iterate over the ncache entry.
	 */
	found = ISC_FALSE;
	dns_name_init(&nsec3name, NULL);
	dns_fixedname_init(&fixed);
	dns_name_downcase(name, dns_fixedname_name(&fixed), NULL);
	name = dns_fixedname_name(&fixed);
	for (result = dns_rdataset_first(rdataset);
	     result == ISC_R_SUCCESS;
	     result = dns_rdataset_next(rdataset))
	{
		dns_ncache_current(rdataset, &nsec3name, &set);
		if (set.type != dns_rdatatype_nsec3) {
			dns_rdataset_disassociate(&set);
			continue;
		}
		dns_name_getlabel(&nsec3name, 0, &hashlabel);
		isc_region_consume(&hashlabel, 1);
		isc_buffer_init(&buffer, owner, sizeof(owner));
		result = isc_base32hex_decoderegion(&hashlabel, &buffer);
		if (result != ISC_R_SUCCESS) {
			dns_rdataset_disassociate(&set);
			continue;
		}
		for (result = dns_rdataset_first(&set);
		     result == ISC_R_SUCCESS;
		     result = dns_rdataset_next(&set))
		{
			dns_rdata_reset(&rdata);
			dns_rdataset_current(&set, &rdata);
			(void)dns_rdata_tostruct(&rdata, &nsec3, NULL);
			if (nsec3.hash != 1)
				continue;
			length = isc_iterated_hash(hash, nsec3.hash,
						   nsec3.iterations, nsec3.salt,
						   nsec3.salt_length,
						   name->ndata, name->length);
			if (length != isc_buffer_usedlength(&buffer))
				continue;
			order = memcmp(hash, owner, length);
			if (order == 0) {
				found = dns_nsec3_typepresent(&rdata,
							      dns_rdatatype_ns);
				dns_rdataset_disassociate(&set);
				return (found);
			}
			if ((nsec3.flags & DNS_NSEC3FLAG_OPTOUT) == 0)
				continue;
			/*
			 * Does this optout span cover the name?
			 */
			scope = memcmp(owner, nsec3.next, nsec3.next_length);
			if ((scope < 0 && order > 0 &&
			     memcmp(hash, nsec3.next, length) < 0) ||
			    (scope >= 0 && (order > 0 ||
					memcmp(hash, nsec3.next, length) < 0)))
			{
				dns_rdataset_disassociate(&set);
				return (ISC_TRUE);
			}
		}
		dns_rdataset_disassociate(&set);
	}
	return (found);
}

/*%
 * We have been asked to look for a key.
 * If found resume the validation process.
 * If not found fail the validation process.
 */
static void
fetch_callback_validator(isc_task_t *task, isc_event_t *event) {
	dns_fetchevent_t *devent;
	dns_validator_t *val;
	dns_rdataset_t *rdataset;
	isc_boolean_t want_destroy;
	isc_result_t result;
	isc_result_t eresult;
	isc_result_t saved_result;

	UNUSED(task);
	INSIST(event->ev_type == DNS_EVENT_FETCHDONE);
	devent = (dns_fetchevent_t *)event;
	val = devent->ev_arg;
	rdataset = &val->frdataset;
	eresult = devent->result;

	/* Free resources which are not of interest. */
	if (devent->node != NULL)
		dns_db_detachnode(devent->db, &devent->node);
	if (devent->db != NULL)
		dns_db_detach(&devent->db);
	if (dns_rdataset_isassociated(&val->fsigrdataset))
		dns_rdataset_disassociate(&val->fsigrdataset);
	isc_event_free(&event);
	dns_resolver_destroyfetch(&val->fetch);

	INSIST(val->event != NULL);

	validator_log(val, ISC_LOG_DEBUG(3), "in fetch_callback_validator");
	LOCK(&val->lock);
	if (CANCELED(val)) {
		validator_done(val, ISC_R_CANCELED);
	} else if (eresult == ISC_R_SUCCESS) {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "keyset with trust %s",
			      dns_trust_totext(rdataset->trust));
		/*
		 * Only extract the dst key if the keyset is secure.
		 */
		if (rdataset->trust >= dns_trust_secure) {
			result = get_dst_key(val, val->siginfo, rdataset);
			if (result == ISC_R_SUCCESS)
				val->keyset = &val->frdataset;
		}
		result = validate(val, ISC_TRUE);
		if (result == DNS_R_NOVALIDSIG &&
		    (val->attributes & VALATTR_TRIEDVERIFY) == 0)
		{
			saved_result = result;
			validator_log(val, ISC_LOG_DEBUG(3),
				      "falling back to insecurity proof");
			val->attributes |= VALATTR_INSECURITY;
			result = proveunsecure(val, ISC_FALSE, ISC_FALSE);
			if (result == DNS_R_NOTINSECURE)
				result = saved_result;
		}
		if (result != DNS_R_WAIT)
			validator_done(val, result);
	} else {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "fetch_callback_validator: got %s",
			      isc_result_totext(eresult));
		if (eresult == ISC_R_CANCELED)
			validator_done(val, eresult);
		else
			validator_done(val, DNS_R_BROKENCHAIN);
	}
	want_destroy = exit_check(val);
	UNLOCK(&val->lock);
	if (want_destroy)
		destroy(val);
}

/*%
 * We were asked to look for a DS record as part of following a key chain
 * upwards.  If found resume the validation process.  If not found fail the
 * validation process.
 */
static void
dsfetched(isc_task_t *task, isc_event_t *event) {
	dns_fetchevent_t *devent;
	dns_validator_t *val;
	dns_rdataset_t *rdataset;
	isc_boolean_t want_destroy;
	isc_result_t result;
	isc_result_t eresult;

	UNUSED(task);
	INSIST(event->ev_type == DNS_EVENT_FETCHDONE);
	devent = (dns_fetchevent_t *)event;
	val = devent->ev_arg;
	rdataset = &val->frdataset;
	eresult = devent->result;

	/* Free resources which are not of interest. */
	if (devent->node != NULL)
		dns_db_detachnode(devent->db, &devent->node);
	if (devent->db != NULL)
		dns_db_detach(&devent->db);
	if (dns_rdataset_isassociated(&val->fsigrdataset))
		dns_rdataset_disassociate(&val->fsigrdataset);
	isc_event_free(&event);
	dns_resolver_destroyfetch(&val->fetch);

	INSIST(val->event != NULL);

	validator_log(val, ISC_LOG_DEBUG(3), "in dsfetched");
	LOCK(&val->lock);
	if (CANCELED(val)) {
		validator_done(val, ISC_R_CANCELED);
	} else if (eresult == ISC_R_SUCCESS) {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "dsset with trust %s",
			       dns_trust_totext(rdataset->trust));
		val->dsset = &val->frdataset;
		result = validatezonekey(val);
		if (result != DNS_R_WAIT)
			validator_done(val, result);
	} else if (eresult == DNS_R_CNAME ||
		   eresult == DNS_R_NXRRSET ||
		   eresult == DNS_R_NCACHENXRRSET ||
		   eresult == DNS_R_SERVFAIL)	/* RFC 1034 parent? */
	{
		validator_log(val, ISC_LOG_DEBUG(3),
			      "falling back to insecurity proof (%s)",
			      dns_result_totext(eresult));
		val->attributes |= VALATTR_INSECURITY;
		result = proveunsecure(val, ISC_FALSE, ISC_FALSE);
		if (result != DNS_R_WAIT)
			validator_done(val, result);
	} else {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "dsfetched: got %s",
			      isc_result_totext(eresult));
		if (eresult == ISC_R_CANCELED)
			validator_done(val, eresult);
		else
			validator_done(val, DNS_R_BROKENCHAIN);
	}
	want_destroy = exit_check(val);
	UNLOCK(&val->lock);
	if (want_destroy)
		destroy(val);
}

/*%
 * We were asked to look for the DS record as part of proving that a
 * name is unsecure.
 *
 * If the DS record doesn't exist and the query name corresponds to
 * a delegation point we are transitioning from a secure zone to a
 * unsecure zone.
 *
 * If the DS record exists it will be secure.  We can continue looking
 * for the break point in the chain of trust.
 */
static void
dsfetched2(isc_task_t *task, isc_event_t *event) {
	dns_fetchevent_t *devent;
	dns_validator_t *val;
	dns_name_t *tname;
	isc_boolean_t want_destroy;
	isc_result_t result;
	isc_result_t eresult;

	UNUSED(task);
	INSIST(event->ev_type == DNS_EVENT_FETCHDONE);
	devent = (dns_fetchevent_t *)event;
	val = devent->ev_arg;
	eresult = devent->result;

	/* Free resources which are not of interest. */
	if (devent->node != NULL)
		dns_db_detachnode(devent->db, &devent->node);
	if (devent->db != NULL)
		dns_db_detach(&devent->db);
	if (dns_rdataset_isassociated(&val->fsigrdataset))
		dns_rdataset_disassociate(&val->fsigrdataset);
	dns_resolver_destroyfetch(&val->fetch);

	INSIST(val->event != NULL);

	validator_log(val, ISC_LOG_DEBUG(3), "in dsfetched2: %s",
		      dns_result_totext(eresult));
	LOCK(&val->lock);
	if (CANCELED(val)) {
		validator_done(val, ISC_R_CANCELED);
	} else if (eresult == DNS_R_CNAME ||
		   eresult == DNS_R_NXRRSET ||
		   eresult == DNS_R_NCACHENXRRSET)
	{
		/*
		 * There is no DS.  If this is a delegation, we're done.
		 */
		tname = dns_fixedname_name(&devent->foundname);
		if (eresult != DNS_R_CNAME &&
		    isdelegation(tname, &val->frdataset, eresult)) {
			if (val->mustbesecure) {
				validator_log(val, ISC_LOG_WARNING,
					      "must be secure failure, no DS"
					      " and this is a delegation");
				validator_done(val, DNS_R_MUSTBESECURE);
			} else if (val->view->dlv == NULL || DLVTRIED(val)) {
				markanswer(val, "dsfetched2");
				validator_done(val, ISC_R_SUCCESS);
			} else {
				result = startfinddlvsep(val, tname);
				if (result != DNS_R_WAIT)
					validator_done(val, result);
			}
		} else {
			result = proveunsecure(val, ISC_FALSE, ISC_TRUE);
			if (result != DNS_R_WAIT)
				validator_done(val, result);
		}
	} else if (eresult == ISC_R_SUCCESS ||
		   eresult == DNS_R_NXDOMAIN ||
		   eresult == DNS_R_NCACHENXDOMAIN)
	{
		/*
		 * There is a DS which may or may not be a zone cut.
		 * In either case we are still in a secure zone resume
		 * validation.
		 */
		result = proveunsecure(val, ISC_TF(eresult == ISC_R_SUCCESS),
				       ISC_TRUE);
		if (result != DNS_R_WAIT)
			validator_done(val, result);
	} else {
		if (eresult == ISC_R_CANCELED)
			validator_done(val, eresult);
		else
			validator_done(val, DNS_R_NOVALIDDS);
	}
	isc_event_free(&event);
	want_destroy = exit_check(val);
	UNLOCK(&val->lock);
	if (want_destroy)
		destroy(val);
}

/*%
 * Callback from when a DNSKEY RRset has been validated.
 *
 * Resumes the stalled validation process.
 */
static void
keyvalidated(isc_task_t *task, isc_event_t *event) {
	dns_validatorevent_t *devent;
	dns_validator_t *val;
	isc_boolean_t want_destroy;
	isc_result_t result;
	isc_result_t eresult;
	isc_result_t saved_result;

	UNUSED(task);
	INSIST(event->ev_type == DNS_EVENT_VALIDATORDONE);

	devent = (dns_validatorevent_t *)event;
	val = devent->ev_arg;
	eresult = devent->result;

	isc_event_free(&event);
	dns_validator_destroy(&val->subvalidator);

	INSIST(val->event != NULL);

	validator_log(val, ISC_LOG_DEBUG(3), "in keyvalidated");
	LOCK(&val->lock);
	if (CANCELED(val)) {
		validator_done(val, ISC_R_CANCELED);
	} else if (eresult == ISC_R_SUCCESS) {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "keyset with trust %s",
			      dns_trust_totext(val->frdataset.trust));
		/*
		 * Only extract the dst key if the keyset is secure.
		 */
		if (val->frdataset.trust >= dns_trust_secure)
			(void) get_dst_key(val, val->siginfo, &val->frdataset);
		result = validate(val, ISC_TRUE);
		if (result == DNS_R_NOVALIDSIG &&
		    (val->attributes & VALATTR_TRIEDVERIFY) == 0)
		{
			saved_result = result;
			validator_log(val, ISC_LOG_DEBUG(3),
				      "falling back to insecurity proof");
			val->attributes |= VALATTR_INSECURITY;
			result = proveunsecure(val, ISC_FALSE, ISC_FALSE);
			if (result == DNS_R_NOTINSECURE)
				result = saved_result;
		}
		if (result != DNS_R_WAIT)
			validator_done(val, result);
	} else {
		if (eresult != DNS_R_BROKENCHAIN) {
			if (dns_rdataset_isassociated(&val->frdataset))
				dns_rdataset_expire(&val->frdataset);
			if (dns_rdataset_isassociated(&val->fsigrdataset))
				dns_rdataset_expire(&val->fsigrdataset);
		}
		validator_log(val, ISC_LOG_DEBUG(3),
			      "keyvalidated: got %s",
			      isc_result_totext(eresult));
		validator_done(val, DNS_R_BROKENCHAIN);
	}
	want_destroy = exit_check(val);
	UNLOCK(&val->lock);
	if (want_destroy)
		destroy(val);
}

/*%
 * Callback when the DS record has been validated.
 *
 * Resumes validation of the zone key or the unsecure zone proof.
 */
static void
dsvalidated(isc_task_t *task, isc_event_t *event) {
	dns_validatorevent_t *devent;
	dns_validator_t *val;
	isc_boolean_t want_destroy;
	isc_result_t result;
	isc_result_t eresult;

	UNUSED(task);
	INSIST(event->ev_type == DNS_EVENT_VALIDATORDONE);

	devent = (dns_validatorevent_t *)event;
	val = devent->ev_arg;
	eresult = devent->result;

	isc_event_free(&event);
	dns_validator_destroy(&val->subvalidator);

	INSIST(val->event != NULL);

	validator_log(val, ISC_LOG_DEBUG(3), "in dsvalidated");
	LOCK(&val->lock);
	if (CANCELED(val)) {
		validator_done(val, ISC_R_CANCELED);
	} else if (eresult == ISC_R_SUCCESS) {
		isc_boolean_t have_dsset;
		dns_name_t *name;
		validator_log(val, ISC_LOG_DEBUG(3),
			      "%s with trust %s",
			      val->frdataset.type == dns_rdatatype_ds ?
			      "dsset" : "ds non-existance",
			      dns_trust_totext(val->frdataset.trust));
		have_dsset = ISC_TF(val->frdataset.type == dns_rdatatype_ds);
		name = dns_fixedname_name(&val->fname);
		if ((val->attributes & VALATTR_INSECURITY) != 0 &&
		    val->frdataset.covers == dns_rdatatype_ds &&
		    NEGATIVE(&val->frdataset) &&
		    isdelegation(name, &val->frdataset, DNS_R_NCACHENXRRSET)) {
			if (val->mustbesecure) {
				validator_log(val, ISC_LOG_WARNING,
					      "must be secure failure, no DS "
					      "and this is a delegation");
				result = DNS_R_MUSTBESECURE;
			} else if (val->view->dlv == NULL || DLVTRIED(val)) {
				markanswer(val, "dsvalidated");
				result = ISC_R_SUCCESS;;
			} else
				result = startfinddlvsep(val, name);
		} else if ((val->attributes & VALATTR_INSECURITY) != 0) {
			result = proveunsecure(val, have_dsset, ISC_TRUE);
		} else
			result = validatezonekey(val);
		if (result != DNS_R_WAIT)
			validator_done(val, result);
	} else {
		if (eresult != DNS_R_BROKENCHAIN) {
			if (dns_rdataset_isassociated(&val->frdataset))
				dns_rdataset_expire(&val->frdataset);
			if (dns_rdataset_isassociated(&val->fsigrdataset))
				dns_rdataset_expire(&val->fsigrdataset);
		}
		validator_log(val, ISC_LOG_DEBUG(3),
			      "dsvalidated: got %s",
			      isc_result_totext(eresult));
		validator_done(val, DNS_R_BROKENCHAIN);
	}
	want_destroy = exit_check(val);
	UNLOCK(&val->lock);
	if (want_destroy)
		destroy(val);
}

/*%
 * Callback when the CNAME record has been validated.
 *
 * Resumes validation of the unsecure zone proof.
 */
static void
cnamevalidated(isc_task_t *task, isc_event_t *event) {
	dns_validatorevent_t *devent;
	dns_validator_t *val;
	isc_boolean_t want_destroy;
	isc_result_t result;
	isc_result_t eresult;

	UNUSED(task);
	INSIST(event->ev_type == DNS_EVENT_VALIDATORDONE);

	devent = (dns_validatorevent_t *)event;
	val = devent->ev_arg;
	eresult = devent->result;

	isc_event_free(&event);
	dns_validator_destroy(&val->subvalidator);

	INSIST(val->event != NULL);
	INSIST((val->attributes & VALATTR_INSECURITY) != 0);

	validator_log(val, ISC_LOG_DEBUG(3), "in cnamevalidated");
	LOCK(&val->lock);
	if (CANCELED(val)) {
		validator_done(val, ISC_R_CANCELED);
	} else if (eresult == ISC_R_SUCCESS) {
		validator_log(val, ISC_LOG_DEBUG(3), "cname with trust %s",
			      dns_trust_totext(val->frdataset.trust));
		result = proveunsecure(val, ISC_FALSE, ISC_TRUE);
		if (result != DNS_R_WAIT)
			validator_done(val, result);
	} else {
		if (eresult != DNS_R_BROKENCHAIN) {
			if (dns_rdataset_isassociated(&val->frdataset))
				dns_rdataset_expire(&val->frdataset);
			if (dns_rdataset_isassociated(&val->fsigrdataset))
				dns_rdataset_expire(&val->fsigrdataset);
		}
		validator_log(val, ISC_LOG_DEBUG(3),
			      "cnamevalidated: got %s",
			      isc_result_totext(eresult));
		validator_done(val, DNS_R_BROKENCHAIN);
	}
	want_destroy = exit_check(val);
	UNLOCK(&val->lock);
	if (want_destroy)
		destroy(val);
}

/*%
 * Return ISC_R_SUCCESS if we can determine that the name doesn't exist
 * or we can determine whether there is data or not at the name.
 * If the name does not exist return the wildcard name.
 *
 * Return ISC_R_IGNORE when the NSEC is not the appropriate one.
 */
static isc_result_t
nsecnoexistnodata(dns_validator_t *val, dns_name_t *name, dns_name_t *nsecname,
		  dns_rdataset_t *nsecset, isc_boolean_t *exists,
		  isc_boolean_t *data, dns_name_t *wild)
{
	int order;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	isc_result_t result;
	dns_namereln_t relation;
	unsigned int olabels, nlabels, labels;
	dns_rdata_nsec_t nsec;
	isc_boolean_t atparent;
	isc_boolean_t ns;
	isc_boolean_t soa;

	REQUIRE(exists != NULL);
	REQUIRE(data != NULL);
	REQUIRE(nsecset != NULL &&
		nsecset->type == dns_rdatatype_nsec);

	result = dns_rdataset_first(nsecset);
	if (result != ISC_R_SUCCESS) {
		validator_log(val, ISC_LOG_DEBUG(3),
			"failure processing NSEC set");
		return (result);
	}
	dns_rdataset_current(nsecset, &rdata);

	validator_log(val, ISC_LOG_DEBUG(3), "looking for relevant nsec");
	relation = dns_name_fullcompare(name, nsecname, &order, &olabels);

	if (order < 0) {
		/*
		 * The name is not within the NSEC range.
		 */
		validator_log(val, ISC_LOG_DEBUG(3),
			      "NSEC does not cover name, before NSEC");
		return (ISC_R_IGNORE);
	}

	if (order == 0) {
		/*
		 * The names are the same.   If we are validating "."
		 * then atparent should not be set as there is no parent.
		 */
		atparent = (olabels != 1) &&
			   dns_rdatatype_atparent(val->event->type);
		ns = dns_nsec_typepresent(&rdata, dns_rdatatype_ns);
		soa = dns_nsec_typepresent(&rdata, dns_rdatatype_soa);
		if (ns && !soa) {
			if (!atparent) {
				/*
				 * This NSEC record is from somewhere higher in
				 * the DNS, and at the parent of a delegation.
				 * It can not be legitimately used here.
				 */
				validator_log(val, ISC_LOG_DEBUG(3),
					      "ignoring parent nsec");
				return (ISC_R_IGNORE);
			}
		} else if (atparent && ns && soa) {
			/*
			 * This NSEC record is from the child.
			 * It can not be legitimately used here.
			 */
			validator_log(val, ISC_LOG_DEBUG(3),
				      "ignoring child nsec");
			return (ISC_R_IGNORE);
		}
		if (val->event->type == dns_rdatatype_cname ||
		    val->event->type == dns_rdatatype_nxt ||
		    val->event->type == dns_rdatatype_nsec ||
		    val->event->type == dns_rdatatype_key ||
		    !dns_nsec_typepresent(&rdata, dns_rdatatype_cname)) {
			*exists = ISC_TRUE;
			*data = dns_nsec_typepresent(&rdata, val->event->type);
			validator_log(val, ISC_LOG_DEBUG(3),
				      "nsec proves name exists (owner) data=%d",
				      *data);
			return (ISC_R_SUCCESS);
		}
		validator_log(val, ISC_LOG_DEBUG(3), "NSEC proves CNAME exists");
		return (ISC_R_IGNORE);
	}

	if (relation == dns_namereln_subdomain &&
	    dns_nsec_typepresent(&rdata, dns_rdatatype_ns) &&
	    !dns_nsec_typepresent(&rdata, dns_rdatatype_soa))
	{
		/*
		 * This NSEC record is from somewhere higher in
		 * the DNS, and at the parent of a delegation.
		 * It can not be legitimately used here.
		 */
		validator_log(val, ISC_LOG_DEBUG(3), "ignoring parent nsec");
		return (ISC_R_IGNORE);
	}

	result = dns_rdata_tostruct(&rdata, &nsec, NULL);
	if (result != ISC_R_SUCCESS)
		return (result);
	relation = dns_name_fullcompare(&nsec.next, name, &order, &nlabels);
	if (order == 0) {
		dns_rdata_freestruct(&nsec);
		validator_log(val, ISC_LOG_DEBUG(3),
			      "ignoring nsec matches next name");
		return (ISC_R_IGNORE);
	}

	if (order < 0 && !dns_name_issubdomain(nsecname, &nsec.next)) {
		/*
		 * The name is not within the NSEC range.
		 */
		dns_rdata_freestruct(&nsec);
		validator_log(val, ISC_LOG_DEBUG(3),
			    "ignoring nsec because name is past end of range");
		return (ISC_R_IGNORE);
	}

	if (order > 0 && relation == dns_namereln_subdomain) {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "nsec proves name exist (empty)");
		dns_rdata_freestruct(&nsec);
		*exists = ISC_TRUE;
		*data = ISC_FALSE;
		return (ISC_R_SUCCESS);
	}
	if (wild != NULL) {
		dns_name_t common;
		dns_name_init(&common, NULL);
		if (olabels > nlabels) {
			labels = dns_name_countlabels(nsecname);
			dns_name_getlabelsequence(nsecname, labels - olabels,
						  olabels, &common);
		} else {
			labels = dns_name_countlabels(&nsec.next);
			dns_name_getlabelsequence(&nsec.next, labels - nlabels,
						  nlabels, &common);
		}
		result = dns_name_concatenate(dns_wildcardname, &common,
					       wild, NULL);
		if (result != ISC_R_SUCCESS) {
			dns_rdata_freestruct(&nsec);
			validator_log(val, ISC_LOG_DEBUG(3),
				    "failure generating wildcard name");
			return (result);
		}
	}
	dns_rdata_freestruct(&nsec);
	validator_log(val, ISC_LOG_DEBUG(3), "nsec range ok");
	*exists = ISC_FALSE;
	return (ISC_R_SUCCESS);
}

static isc_result_t
nsec3noexistnodata(dns_validator_t *val, dns_name_t* name,
		   dns_name_t *nsec3name, dns_rdataset_t *nsec3set,
		   dns_name_t *zonename, isc_boolean_t *exists,
		   isc_boolean_t *data, isc_boolean_t *optout,
		   isc_boolean_t *unknown, isc_boolean_t *setclosest,
		   isc_boolean_t *setnearest, dns_name_t *closest,
		   dns_name_t *nearest)
{
	char namebuf[DNS_NAME_FORMATSIZE];
	dns_fixedname_t fzone;
	dns_fixedname_t qfixed;
	dns_label_t hashlabel;
	dns_name_t *qname;
	dns_name_t *zone;
	dns_rdata_nsec3_t nsec3;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	int order;
	int scope;
	isc_boolean_t atparent;
	isc_boolean_t first;
	isc_boolean_t ns;
	isc_boolean_t soa;
	isc_buffer_t buffer;
	isc_result_t answer = ISC_R_IGNORE;
	isc_result_t result;
	unsigned char hash[NSEC3_MAX_HASH_LENGTH];
	unsigned char owner[NSEC3_MAX_HASH_LENGTH];
	unsigned int length;
	unsigned int qlabels;
	unsigned int zlabels;

	REQUIRE((exists == NULL && data == NULL) ||
		(exists != NULL && data != NULL));
	REQUIRE(nsec3set != NULL && nsec3set->type == dns_rdatatype_nsec3);
	REQUIRE((setclosest == NULL && closest == NULL) ||
		(setclosest != NULL && closest != NULL));
	REQUIRE((setnearest == NULL && nearest == NULL) ||
		(setnearest != NULL && nearest != NULL));

	result = dns_rdataset_first(nsec3set);
	if (result != ISC_R_SUCCESS) {
		validator_log(val, ISC_LOG_DEBUG(3),
			"failure processing NSEC3 set");
		return (result);
	}

	dns_rdataset_current(nsec3set, &rdata);

	result = dns_rdata_tostruct(&rdata, &nsec3, NULL);
	if (result != ISC_R_SUCCESS)
		return (result);

	validator_log(val, ISC_LOG_DEBUG(3), "looking for relevant NSEC3");

	dns_fixedname_init(&fzone);
	zone = dns_fixedname_name(&fzone);
	zlabels = dns_name_countlabels(nsec3name);

	/*
	 * NSEC3 records must have two or more labels to be valid.
	 */
	if (zlabels < 2)
		return (ISC_R_IGNORE);

	/*
	 * Strip off the NSEC3 hash to get the zone.
	 */
	zlabels--;
	dns_name_split(nsec3name, zlabels, NULL, zone);

	/*
	 * If not below the zone name we can ignore this record.
	 */
	if (!dns_name_issubdomain(name, zone))
		return (ISC_R_IGNORE);

	/*
	 * Is this zone the same or deeper than the current zone?
	 */
	if (dns_name_countlabels(zonename) == 0 ||
	    dns_name_issubdomain(zone, zonename))
		dns_name_copy(zone, zonename, NULL);

	if (!dns_name_equal(zone, zonename))
		return (ISC_R_IGNORE);

	/*
	 * Are we only looking for the most enclosing zone?
	 */
	if (exists == NULL || data == NULL)
		return (ISC_R_SUCCESS);

	/*
	 * Only set unknown once we are sure that this NSEC3 is from
	 * the deepest covering zone.
	 */
	if (!dns_nsec3_supportedhash(nsec3.hash)) {
		if (unknown != NULL)
			*unknown = ISC_TRUE;
		return (ISC_R_IGNORE);
	}

	/*
	 * Recover the hash from the first label.
	 */
	dns_name_getlabel(nsec3name, 0, &hashlabel);
	isc_region_consume(&hashlabel, 1);
	isc_buffer_init(&buffer, owner, sizeof(owner));
	result = isc_base32hex_decoderegion(&hashlabel, &buffer);
	if (result != ISC_R_SUCCESS)
		return (result);

	/*
	 * The hash lengths should match.  If not ignore the record.
	 */
	if (isc_buffer_usedlength(&buffer) != nsec3.next_length)
		return (ISC_R_IGNORE);

	/*
	 * Work out what this NSEC3 covers.
	 * Inside (<0) or outside (>=0).
	 */
	scope = memcmp(owner, nsec3.next, nsec3.next_length);

	/*
	 * Prepare to compute all the hashes.
	 */
	dns_fixedname_init(&qfixed);
	qname = dns_fixedname_name(&qfixed);
	dns_name_downcase(name, qname, NULL);
	qlabels = dns_name_countlabels(qname);
	first = ISC_TRUE;

	while (qlabels >= zlabels) {
		length = isc_iterated_hash(hash, nsec3.hash, nsec3.iterations,
					   nsec3.salt, nsec3.salt_length,
					   qname->ndata, qname->length);
		/*
		 * The computed hash length should match.
		 */
		if (length != nsec3.next_length) {
			validator_log(val, ISC_LOG_DEBUG(3),
				      "ignoring NSEC bad length %u vs %u",
				      length, nsec3.next_length);
			return (ISC_R_IGNORE);
		}

		order = memcmp(hash, owner, length);
		if (first && order == 0) {
			/*
			 * The hashes are the same.
			 */
			atparent = dns_rdatatype_atparent(val->event->type);
			ns = dns_nsec3_typepresent(&rdata, dns_rdatatype_ns);
			soa = dns_nsec3_typepresent(&rdata, dns_rdatatype_soa);
			if (ns && !soa) {
				if (!atparent) {
					/*
					 * This NSEC3 record is from somewhere
					 * higher in the DNS, and at the
					 * parent of a delegation. It can not
					 * be legitimately used here.
					 */
					validator_log(val, ISC_LOG_DEBUG(3),
						      "ignoring parent NSEC3");
					return (ISC_R_IGNORE);
				}
			} else if (atparent && ns && soa) {
				/*
				 * This NSEC3 record is from the child.
				 * It can not be legitimately used here.
				 */
				validator_log(val, ISC_LOG_DEBUG(3),
					      "ignoring child NSEC3");
				return (ISC_R_IGNORE);
			}
			if (val->event->type == dns_rdatatype_cname ||
			    val->event->type == dns_rdatatype_nxt ||
			    val->event->type == dns_rdatatype_nsec ||
			    val->event->type == dns_rdatatype_key ||
			    !dns_nsec3_typepresent(&rdata, dns_rdatatype_cname)) {
				*exists = ISC_TRUE;
				*data = dns_nsec3_typepresent(&rdata,
							      val->event->type);
				validator_log(val, ISC_LOG_DEBUG(3),
					      "NSEC3 proves name exists (owner) "
					      "data=%d", *data);
				return (ISC_R_SUCCESS);
			}
			validator_log(val, ISC_LOG_DEBUG(3),
				      "NSEC3 proves CNAME exists");
			return (ISC_R_IGNORE);
		}

		if (order == 0 &&
		    dns_nsec3_typepresent(&rdata, dns_rdatatype_ns) &&
		    !dns_nsec3_typepresent(&rdata, dns_rdatatype_soa))
		{
			/*
			 * This NSEC3 record is from somewhere higher in
			 * the DNS, and at the parent of a delegation.
			 * It can not be legitimately used here.
			 */
			validator_log(val, ISC_LOG_DEBUG(3),
				      "ignoring parent NSEC3");
			return (ISC_R_IGNORE);
		}

		/*
		 * Potential closest encloser.
		 */
		if (order == 0) {
			if (closest != NULL &&
			    (dns_name_countlabels(closest) == 0 ||
			     dns_name_issubdomain(qname, closest)) &&
			    !dns_nsec3_typepresent(&rdata, dns_rdatatype_ds) &&
			    !dns_nsec3_typepresent(&rdata, dns_rdatatype_dname) &&
			    (dns_nsec3_typepresent(&rdata, dns_rdatatype_soa) ||
			     !dns_nsec3_typepresent(&rdata, dns_rdatatype_ns)))
			{

				dns_name_format(qname, namebuf,
						sizeof(namebuf));
				validator_log(val, ISC_LOG_DEBUG(3),
					      "NSEC3 indicates potential "
					      "closest encloser: '%s'",
					       namebuf);
				dns_name_copy(qname, closest, NULL);
				*setclosest = ISC_TRUE;
			}
			dns_name_format(qname, namebuf, sizeof(namebuf));
			validator_log(val, ISC_LOG_DEBUG(3),
				      "NSEC3 at super-domain %s", namebuf);
			return (answer);
		}

		/*
		 * Find if the name does not exist.
		 *
		 * We continue as we need to find the name closest to the
		 * closest encloser that doesn't exist.
		 *
		 * We also need to continue to ensure that we are not
		 * proving the non-existence of a record in a sub-zone.
		 * If that would be the case we will return ISC_R_IGNORE
		 * above.
		 */
		if ((scope < 0 && order > 0 &&
		     memcmp(hash, nsec3.next, length) < 0) ||
		    (scope >= 0 && (order > 0 ||
				    memcmp(hash, nsec3.next, length) < 0)))
		{
			char namebuf[DNS_NAME_FORMATSIZE];

			dns_name_format(qname, namebuf, sizeof(namebuf));
			validator_log(val, ISC_LOG_DEBUG(3), "NSEC3 proves "
				      "name does not exist: '%s'", namebuf);
			if (nearest != NULL &&
			    (dns_name_countlabels(nearest) == 0 ||
			     dns_name_issubdomain(nearest, qname))) {
				dns_name_copy(qname, nearest, NULL);
				*setnearest = ISC_TRUE;
			}

			*exists = ISC_FALSE;
			*data = ISC_FALSE;
			if (optout != NULL) {
				if ((nsec3.flags & DNS_NSEC3FLAG_OPTOUT) != 0)
					validator_log(val, ISC_LOG_DEBUG(3),
						      "NSEC3 indicates optout");
				*optout =
				    ISC_TF(nsec3.flags & DNS_NSEC3FLAG_OPTOUT);
			}
			answer = ISC_R_SUCCESS;
		}

		qlabels--;
		if (qlabels > 0)
			dns_name_split(qname, qlabels, NULL, qname);
		first = ISC_FALSE;
	}
	return (answer);
}

/*%
 * Callback for when NSEC records have been validated.
 *
 * Looks for NOQNAME, NODATA and OPTOUT proofs.
 *
 * Resumes nsecvalidate.
 */
static void
authvalidated(isc_task_t *task, isc_event_t *event) {
	dns_validatorevent_t *devent;
	dns_validator_t *val;
	dns_rdataset_t *rdataset;
	isc_boolean_t want_destroy;
	isc_result_t result;
	isc_boolean_t exists, data;

	UNUSED(task);
	INSIST(event->ev_type == DNS_EVENT_VALIDATORDONE);

	devent = (dns_validatorevent_t *)event;
	rdataset = devent->rdataset;
	val = devent->ev_arg;
	result = devent->result;
	dns_validator_destroy(&val->subvalidator);

	INSIST(val->event != NULL);

	validator_log(val, ISC_LOG_DEBUG(3), "in authvalidated");
	LOCK(&val->lock);
	if (CANCELED(val)) {
		validator_done(val, ISC_R_CANCELED);
	} else if (result != ISC_R_SUCCESS) {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "authvalidated: got %s",
			      isc_result_totext(result));
		if (result == DNS_R_BROKENCHAIN)
			val->authfail++;
		if (result == ISC_R_CANCELED)
			validator_done(val, result);
		else {
			result = nsecvalidate(val, ISC_TRUE);
			if (result != DNS_R_WAIT)
				validator_done(val, result);
		}
	} else {
		dns_name_t **proofs = val->event->proofs;
		dns_name_t *wild = dns_fixedname_name(&val->wild);

		if (rdataset->trust == dns_trust_secure)
			val->seensig = ISC_TRUE;

		if (rdataset->type == dns_rdatatype_nsec &&
		    rdataset->trust == dns_trust_secure &&
		    (NEEDNODATA(val) || NEEDNOQNAME(val)) &&
		    !FOUNDNODATA(val) && !FOUNDNOQNAME(val) &&
		    nsecnoexistnodata(val, val->event->name, devent->name,
				      rdataset, &exists, &data, wild)
				      == ISC_R_SUCCESS)
		{
			if (exists && !data) {
				val->attributes |= VALATTR_FOUNDNODATA;
				if (NEEDNODATA(val))
					proofs[DNS_VALIDATOR_NODATAPROOF] =
						devent->name;
			}
			if (!exists) {
				val->attributes |= VALATTR_FOUNDNOQNAME;
				val->attributes |= VALATTR_FOUNDCLOSEST;
				/*
				 * The NSEC noqname proof also contains
				 * the closest encloser.

				 */
				if (NEEDNOQNAME(val))
					proofs[DNS_VALIDATOR_NOQNAMEPROOF] =
						devent->name;
			}
		}

		result = nsecvalidate(val, ISC_TRUE);
		if (result != DNS_R_WAIT)
			validator_done(val, result);
	}
	want_destroy = exit_check(val);
	UNLOCK(&val->lock);
	if (want_destroy)
		destroy(val);

	/*
	 * Free stuff from the event.
	 */
	isc_event_free(&event);
}

/*%
 * Looks for the requested name and type in the view (zones and cache).
 *
 * When looking for a DLV record also checks to make sure the NSEC record
 * returns covers the query name as part of aggressive negative caching.
 *
 * Returns:
 * \li	ISC_R_SUCCESS
 * \li	ISC_R_NOTFOUND
 * \li	DNS_R_NCACHENXDOMAIN
 * \li	DNS_R_NCACHENXRRSET
 * \li	DNS_R_NXRRSET
 * \li	DNS_R_NXDOMAIN
 * \li	DNS_R_BROKENCHAIN
 */
static inline isc_result_t
view_find(dns_validator_t *val, dns_name_t *name, dns_rdatatype_t type) {
	dns_fixedname_t fixedname;
	dns_name_t *foundname;
	dns_rdata_nsec_t nsec;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	isc_result_t result;
	unsigned int options;
	isc_time_t now;
	char buf1[DNS_NAME_FORMATSIZE];
	char buf2[DNS_NAME_FORMATSIZE];
	char buf3[DNS_NAME_FORMATSIZE];
	char namebuf[DNS_NAME_FORMATSIZE];
	char typebuf[DNS_RDATATYPE_FORMATSIZE];

	if (dns_rdataset_isassociated(&val->frdataset))
		dns_rdataset_disassociate(&val->frdataset);
	if (dns_rdataset_isassociated(&val->fsigrdataset))
		dns_rdataset_disassociate(&val->fsigrdataset);

	if (val->view->zonetable == NULL)
		return (ISC_R_CANCELED);

	if (isc_time_now(&now) == ISC_R_SUCCESS &&
	    dns_resolver_getbadcache(val->view->resolver, name, type, &now)) {

		dns_name_format(name, namebuf, sizeof(namebuf));
		dns_rdatatype_format(type, typebuf, sizeof(typebuf));
		validator_log(val, ISC_LOG_INFO, "bad cache hit (%s/%s)",
			      namebuf, typebuf);
		return (DNS_R_BROKENCHAIN);
	}

	options = DNS_DBFIND_PENDINGOK;
	if (type == dns_rdatatype_dlv)
		options |= DNS_DBFIND_COVERINGNSEC;
	dns_fixedname_init(&fixedname);
	foundname = dns_fixedname_name(&fixedname);
	result = dns_view_find(val->view, name, type, 0, options,
			       ISC_FALSE, NULL, NULL, foundname,
			       &val->frdataset, &val->fsigrdataset);

	if (result == DNS_R_NXDOMAIN) {
		if (dns_rdataset_isassociated(&val->frdataset))
			dns_rdataset_disassociate(&val->frdataset);
		if (dns_rdataset_isassociated(&val->fsigrdataset))
			dns_rdataset_disassociate(&val->fsigrdataset);
	} else if (result == DNS_R_COVERINGNSEC) {
		validator_log(val, ISC_LOG_DEBUG(3), "DNS_R_COVERINGNSEC");
		/*
		 * Check if the returned NSEC covers the name.
		 */
		INSIST(type == dns_rdatatype_dlv);
		if (val->frdataset.trust != dns_trust_secure) {
			validator_log(val, ISC_LOG_DEBUG(3),
				      "covering nsec: trust %s",
				      dns_trust_totext(val->frdataset.trust));
			goto notfound;
		}
		result = dns_rdataset_first(&val->frdataset);
		if (result != ISC_R_SUCCESS)
			goto notfound;
		dns_rdataset_current(&val->frdataset, &rdata);
		if (dns_nsec_typepresent(&rdata, dns_rdatatype_ns) &&
		    !dns_nsec_typepresent(&rdata, dns_rdatatype_soa)) {
			/* Parent NSEC record. */
			if (dns_name_issubdomain(name, foundname)) {
				validator_log(val, ISC_LOG_DEBUG(3),
					      "covering nsec: for parent");
				goto notfound;
			}
		}
		result = dns_rdata_tostruct(&rdata, &nsec, NULL);
		if (result != ISC_R_SUCCESS)
			goto notfound;
		if (dns_name_compare(foundname, &nsec.next) >= 0) {
			/* End of zone chain. */
			if (!dns_name_issubdomain(name, &nsec.next)) {
				/*
				 * XXXMPA We could look for a parent NSEC
				 * at nsec.next and if found retest with
				 * this NSEC.
				 */
				dns_rdata_freestruct(&nsec);
				validator_log(val, ISC_LOG_DEBUG(3),
					      "covering nsec: not in zone");
				goto notfound;
			}
		} else if (dns_name_compare(name, &nsec.next) >= 0) {
			/*
			 * XXXMPA We could check if this NSEC is at a zone
			 * apex and if the qname is not below it and look for
			 * a parent NSEC with the same name.  This requires
			 * that we can cache both NSEC records which we
			 * currently don't support.
			 */
			dns_rdata_freestruct(&nsec);
			validator_log(val, ISC_LOG_DEBUG(3),
				      "covering nsec: not in range");
			goto notfound;
		}
		if (isc_log_wouldlog(dns_lctx,ISC_LOG_DEBUG(3))) {
			dns_name_format(name, buf1, sizeof buf1);
			dns_name_format(foundname, buf2, sizeof buf2);
			dns_name_format(&nsec.next, buf3, sizeof buf3);
			validator_log(val, ISC_LOG_DEBUG(3),
				      "covering nsec found: '%s' '%s' '%s'",
				      buf1, buf2, buf3);
		}
		if (dns_rdataset_isassociated(&val->frdataset))
			dns_rdataset_disassociate(&val->frdataset);
		if (dns_rdataset_isassociated(&val->fsigrdataset))
			dns_rdataset_disassociate(&val->fsigrdataset);
		dns_rdata_freestruct(&nsec);
		result = DNS_R_NCACHENXDOMAIN;
	} else if (result != ISC_R_SUCCESS &&
		   result != DNS_R_NCACHENXDOMAIN &&
		   result != DNS_R_NCACHENXRRSET &&
		   result != DNS_R_EMPTYNAME &&
		   result != DNS_R_NXRRSET &&
		   result != ISC_R_NOTFOUND) {
		goto  notfound;
	}
	return (result);

 notfound:
	if (dns_rdataset_isassociated(&val->frdataset))
		dns_rdataset_disassociate(&val->frdataset);
	if (dns_rdataset_isassociated(&val->fsigrdataset))
		dns_rdataset_disassociate(&val->fsigrdataset);
	return (ISC_R_NOTFOUND);
}

/*%
 * Checks to make sure we are not going to loop.  As we use a SHARED fetch
 * the validation process will stall if looping was to occur.
 */
static inline isc_boolean_t
check_deadlock(dns_validator_t *val, dns_name_t *name, dns_rdatatype_t type,
	       dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset)
{
	dns_validator_t *parent;

	for (parent = val; parent != NULL; parent = parent->parent) {
		if (parent->event != NULL &&
		    parent->event->type == type &&
		    dns_name_equal(parent->event->name, name) &&
		    /*
		     * As NSEC3 records are meta data you sometimes
		     * need to prove a NSEC3 record which says that
		     * itself doesn't exist.
		     */
		    (parent->event->type != dns_rdatatype_nsec3 ||
		     rdataset == NULL || sigrdataset == NULL ||
		     parent->event->message == NULL ||
		     parent->event->rdataset != NULL ||
		     parent->event->sigrdataset != NULL))
		{
			validator_log(val, ISC_LOG_DEBUG(3),
				      "continuing validation would lead to "
				      "deadlock: aborting validation");
			return (ISC_TRUE);
		}
	}
	return (ISC_FALSE);
}

/*%
 * Start a fetch for the requested name and type.
 */
static inline isc_result_t
create_fetch(dns_validator_t *val, dns_name_t *name, dns_rdatatype_t type,
	     isc_taskaction_t callback, const char *caller)
{
	if (dns_rdataset_isassociated(&val->frdataset))
		dns_rdataset_disassociate(&val->frdataset);
	if (dns_rdataset_isassociated(&val->fsigrdataset))
		dns_rdataset_disassociate(&val->fsigrdataset);

	if (check_deadlock(val, name, type, NULL, NULL)) {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "deadlock found (create_fetch)");
		return (DNS_R_NOVALIDSIG);
	}

	validator_logcreate(val, name, type, caller, "fetch");
	return (dns_resolver_createfetch(val->view->resolver, name, type,
					 NULL, NULL, NULL, 0,
					 val->event->ev_sender,
					 callback, val,
					 &val->frdataset,
					 &val->fsigrdataset,
					 &val->fetch));
}

/*%
 * Start a subvalidation process.
 */
static inline isc_result_t
create_validator(dns_validator_t *val, dns_name_t *name, dns_rdatatype_t type,
		 dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
		 isc_taskaction_t action, const char *caller)
{
	isc_result_t result;

	if (check_deadlock(val, name, type, rdataset, sigrdataset)) {
		validator_log(val, ISC_LOG_DEBUG(3),
			      "deadlock found (create_validator)");
		return (DNS_R_NOVALIDSIG);
	}

	validator_logcreate(val, name, type, caller, "validator");
	result = dns_validator_create(val->view, name, type,
				      rdataset, sigrdataset, NULL, 0,
				      val->task, action, val,
				      &val->subvalidator);
	if (result == ISC_R_SUCCESS) {
		val->subvalidator->parent = val;
		val->subvalidator->depth = val->depth + 1;
	}
	return (result);
}

/*%
 * Try to find a key that could have signed 'siginfo' among those
 * in 'rdataset'.  If found, build a dst_key_t for it and point
 * val->key at it.
 *
 * If val->key is non-NULL, this returns the next matching key.
 */
static isc_result_t
get_dst_key(dns_validator_t *val, dns_rdata_rrsig_t *siginfo,
	    dns_rdataset_t *rdataset)
{
	isc_result_t result;
	isc_buffer_t b;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	dst_key_t *oldkey = val->key;
	isc_boolean_t foundold;

	if (oldkey == NULL)
		foundold = ISC_TRUE;
	else {
		foundold = ISC_FALSE;
		val->key = NULL;
	}

	result = dns_rdataset_first(rdataset);
	if (result != ISC_R_SUCCESS)
		goto failure;
	do {
		dns_rdataset_current(rdataset, &rdata);

		isc_buffer_init(&b, rdata.data, rdata.length);
		isc_buffer_add(&b, rdata.length);
		INSIST(val->key == NULL);
		result = dst_key_fromdns(&siginfo->signer, rdata.rdclass, &b,
					 val->view->mctx, &val->key);
		if (result != ISC_R_SUCCESS)
			goto failure;
		if (siginfo->algorithm ==
		    (dns_secalg_t)dst_key_alg(val->key) &&
		    siginfo->keyid ==
		    (dns_keytag_t)dst_key_id(val->key) &&
		    dst_key_iszonekey(val->key))
		{
			if (foundold)
				/*
				 * This is the key we're looking for.
				 */
				return (ISC_R_SUCCESS);
			else if (dst_key_compare(oldkey, val->key) == ISC_TRUE)
			{
				foundold = ISC_TRUE;
				dst_key_free(&oldkey);
			}
		}
		dst_key_free(&val->key);
		dns_rdata_reset(&rdata);
		result = dns_rdataset_next(rdataset);
	} while (result == ISC_R_SUCCESS);
	if (result == ISC_R_NOMORE)
		result = ISC_R_NOTFOUND;

 failure:
	if (oldkey != NULL)
		dst_key_free(&oldkey);

	return (result);
}

/*%
 * Get the key that generated this signature.
 */
static isc_result_t
get_key(dns_validator_t *val, dns_rdata_rrsig_t *siginfo) {
	isc_result_t result;
	unsigned int nlabels;
	int order;
	dns_namereln_t namereln;

	/*
	 * Is the signer name appropriate for this signature?
	 *
	 * The signer name must be at the same level as the owner name
	 * or closer to the DNS root.
	 */
	namereln = dns_name_fullcompare(val->event->name, &siginfo->signer,
					&order, &nlabels);
	if (namereln != dns_namereln_subdomain &&
	    namereln != dns…