view.h

/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

#ifndef DNS_VIEW_H
#define DNS_VIEW_H 1

/*****
 ***** Module Info
 *****/

/*! \file dns/view.h
 * \brief
 * DNS View
 *
 * A "view" is a DNS namespace, together with an optional resolver and a
 * forwarding policy.  A "DNS namespace" is a (possibly empty) set of
 * authoritative zones together with an optional cache and optional
 * "hints" information.
 *
 * Views start out "unfrozen".  In this state, core attributes like
 * the cache, set of zones, and forwarding policy may be set.  While
 * "unfrozen", the caller (e.g. nameserver configuration loading
 * code), must ensure exclusive access to the view.  When the view is
 * "frozen", the core attributes become immutable, and the view module
 * will ensure synchronization.  Freezing allows the view's core attributes
 * to be accessed without locking.
 *
 * MP:
 *\li	Before the view is frozen, the caller must ensure synchronization.
 *
 *\li	After the view is frozen, the module guarantees appropriate
 *	synchronization of any data structures it creates and manipulates.
 *
 * Reliability:
 *\li	No anticipated impact.
 *
 * Resources:
 *\li	TBS
 *
 * Security:
 *\li	No anticipated impact.
 *
 * Standards:
 *\li	None.
 */

#include <stdbool.h>
#include <stdio.h>
#include <inttypes.h>

#include <isc/lang.h>
#include <isc/magic.h>
#include <isc/event.h>
#include <isc/mutex.h>
#include <isc/net.h>
#include <isc/refcount.h>
#include <isc/rwlock.h>
#include <isc/stdtime.h>

#include <dns/acl.h>
#include <dns/catz.h>
#include <dns/clientinfo.h>
#include <dns/dnstap.h>
#include <dns/fixedname.h>
#include <dns/rrl.h>
#include <dns/rdatastruct.h>
#include <dns/rpz.h>
#include <dns/types.h>
#include <dns/zt.h>

ISC_LANG_BEGINDECLS

struct dns_view {
	/* Unlocked. */
	unsigned int			magic;
	isc_mem_t *			mctx;
	dns_rdataclass_t		rdclass;
	char *				name;
	dns_zt_t *			zonetable;
	dns_resolver_t *		resolver;
	dns_adb_t *			adb;
	dns_requestmgr_t *		requestmgr;
	dns_cache_t *			cache;
	dns_db_t *			cachedb;
	dns_db_t *			hints;

	/*
	 * security roots and negative trust anchors.
	 * internal use only; access via * dns_view_getsecroots()
	 */
	dns_keytable_t *		secroots_priv;
	dns_ntatable_t *		ntatable_priv;

	isc_mutex_t			lock;
	bool				frozen;
	isc_task_t *			task;
	isc_event_t			resevent;
	isc_event_t			adbevent;
	isc_event_t			reqevent;
	isc_stats_t *			adbstats;
	isc_stats_t *			resstats;
	dns_stats_t *			resquerystats;
	bool				cacheshared;

	/* Configurable data. */
	dns_tsig_keyring_t *		statickeys;
	dns_tsig_keyring_t *		dynamickeys;
	dns_peerlist_t *		peers;
	dns_order_t *			order;
	dns_fwdtable_t *		fwdtable;
	bool				recursion;
	bool				qminimization;
	bool				qmin_strict;
	bool				auth_nxdomain;
	bool				use_glue_cache;
	bool				minimal_any;
	dns_minimaltype_t		minimalresponses;
	bool				enablevalidation;
	bool				acceptexpired;
	bool				requireservercookie;
	bool				synthfromdnssec;
	bool				trust_anchor_telemetry;
	bool				root_key_sentinel;
	dns_transfer_format_t		transfer_format;
	dns_acl_t *			cacheacl;
	dns_acl_t *			cacheonacl;
	dns_acl_t *			queryacl;
	dns_acl_t *			queryonacl;
	dns_acl_t *			recursionacl;
	dns_acl_t *			recursiononacl;
	dns_acl_t *			sortlist;
	dns_acl_t *			notifyacl;
	dns_acl_t *			transferacl;
	dns_acl_t *			updateacl;
	dns_acl_t *			upfwdacl;
	dns_acl_t *			denyansweracl;
	dns_acl_t *			nocasecompress;
	bool				msgcompression;
	dns_rbt_t *			answeracl_exclude;
	dns_rbt_t *			denyanswernames;
	dns_rbt_t *			answernames_exclude;
	dns_rrl_t *			rrl;
	bool				provideixfr;
	bool				requestnsid;
	bool				sendcookie;
	dns_ttl_t			maxcachettl;
	dns_ttl_t			maxncachettl;
	dns_ttl_t			mincachettl;
	dns_ttl_t			minncachettl;
	uint32_t			nta_lifetime;
	uint32_t			nta_recheck;
	char				*nta_file;
	dns_ttl_t			prefetch_trigger;
	dns_ttl_t			prefetch_eligible;
	in_port_t			dstport;
	dns_aclenv_t			aclenv;
	dns_rdatatype_t			preferred_glue;
	bool				flush;
	dns_namelist_t *		delonly;
	bool				rootdelonly;
	dns_namelist_t *		rootexclude;
	bool				checknames;
	dns_name_t *			dlv;
	dns_fixedname_t			dlv_fixed;
	uint16_t			maxudp;
	dns_ttl_t			staleanswerttl;
	dns_stale_answer_t		staleanswersok;		/* rndc setting */
	bool				staleanswersenable;	/* named.conf setting */
	uint16_t			nocookieudp;
	uint16_t			padding;
	dns_acl_t *			pad_acl;
	unsigned int			maxbits;
	dns_dns64list_t 		dns64;
	unsigned int 			dns64cnt;
	dns_rpz_zones_t			*rpzs;
	dns_catz_zones_t		*catzs;
	dns_dlzdblist_t 		dlz_searched;
	dns_dlzdblist_t 		dlz_unsearched;
	uint32_t			fail_ttl;
	dns_badcache_t			*failcache;

	/*
	 * Configurable data for server use only,
	 * locked by server configuration lock.
	 */
	dns_acl_t *			matchclients;
	dns_acl_t *			matchdestinations;
	bool				matchrecursiveonly;

	/* Locked by themselves. */
	isc_refcount_t			references;

	/* Locked by lock. */
	unsigned int			weakrefs;
	unsigned int			attributes;
	/* Under owner's locking control. */
	ISC_LINK(struct dns_view)	link;
	dns_viewlist_t *		viewlist;

	dns_zone_t *			managed_keys;
	dns_zone_t *			redirect;
	dns_name_t *			redirectzone;	/* points to
							 * redirectfixed
							 * when valid */
	dns_fixedname_t 		redirectfixed;

	/*
	 * File and configuration data for zones added at runtime
	 * (only used in BIND9).
	 *
	 * XXX: This should be a pointer to an opaque type that
	 * named implements.
	 */
	char *				new_zone_dir;
	char *				new_zone_file;
	char *				new_zone_db;
	void *				new_zone_dbenv;
	uint64_t			new_zone_mapsize;
	void *				new_zone_config;
	void				(*cfg_destroy)(void **);
	isc_mutex_t			new_zone_lock;

	unsigned char			secret[32];	/* Client secret */
	unsigned int			v6bias;

	dns_dtenv_t			*dtenv;		/* Dnstap environment */
	dns_dtmsgtype_t			dttypes;	/* Dnstap message types
							   to log */

	/* Registered module instances */
	void				*plugins;
	void				(*plugins_free)(isc_mem_t *, void **);

	/* Hook table */
	void				*hooktable;	/* ns_hooktable */
	void				(*hooktable_free)(isc_mem_t *, void **);

};

#define DNS_VIEW_MAGIC			ISC_MAGIC('V','i','e','w')
#define DNS_VIEW_VALID(view)		ISC_MAGIC_VALID(view, DNS_VIEW_MAGIC)

#define DNS_VIEWATTR_RESSHUTDOWN	0x01
#define DNS_VIEWATTR_ADBSHUTDOWN	0x02
#define DNS_VIEWATTR_REQSHUTDOWN	0x04

#ifdef HAVE_LMDB
#include <lmdb.h>
/*
 * MDB_NOTLS is used to prevent problems after configuration is reloaded, due
 * to the way LMDB's use of thread-local storage (TLS) interacts with the BIND9
 * thread model.
 */
#define DNS_LMDB_COMMON_FLAGS		(MDB_CREATE | MDB_NOSUBDIR | MDB_NOTLS)
#ifndef __OpenBSD__
#define DNS_LMDB_FLAGS			(DNS_LMDB_COMMON_FLAGS)
#else /* __OpenBSD__ */
/*
 * OpenBSD does not have a unified buffer cache, which requires both reads and
 * writes to be performed using mmap().
 */
#define DNS_LMDB_FLAGS			(DNS_LMDB_COMMON_FLAGS | MDB_WRITEMAP)
#endif /* __OpenBSD__ */
#endif /* HAVE_LMDB */

isc_result_t
dns_view_create(isc_mem_t *mctx, dns_rdataclass_t rdclass,
		const char *name, dns_view_t **viewp);
/*%<
 * Create a view.
 *
 * Notes:
 *
 *\li	The newly created view has no cache, no resolver, and an empty
 *	zone table.  The view is not frozen.
 *
 * Requires:
 *
 *\li	'mctx' is a valid memory context.
 *
 *\li	'rdclass' is a valid class.
 *
 *\li	'name' is a valid C string.
 *
 *\li	viewp != NULL && *viewp == NULL
 *
 * Returns:
 *
 *\li	#ISC_R_SUCCESS
 *\li	#ISC_R_NOMEMORY
 *
 *\li	Other errors are possible.
 */

void
dns_view_attach(dns_view_t *source, dns_view_t **targetp);
/*%<
 * Attach '*targetp' to 'source'.
 *
 * Requires:
 *
 *\li	'source' is a valid, frozen view.
 *
 *\li	'targetp' points to a NULL dns_view_t *.
 *
 * Ensures:
 *
 *\li	*targetp is attached to source.
 *
 *\li	While *targetp is attached, the view will not shut down.
 */

void
dns_view_detach(dns_view_t **viewp);
/*%<
 * Detach '*viewp' from its view.
 *
 * Requires:
 *
 *\li	'viewp' points to a valid dns_view_t *
 *
 * Ensures:
 *
 *\li	*viewp is NULL.
 */

void
dns_view_flushanddetach(dns_view_t **viewp);
/*%<
 * Detach '*viewp' from its view.  If this was the last reference
 * uncommitted changed in zones will be flushed to disk.
 *
 * Requires:
 *
 *\li	'viewp' points to a valid dns_view_t *
 *
 * Ensures:
 *
 *\li	*viewp is NULL.
 */

void
dns_view_weakattach(dns_view_t *source, dns_view_t **targetp);
/*%<
 * Weakly attach '*targetp' to 'source'.
 *
 * Requires:
 *
 *\li	'source' is a valid, frozen view.
 *
 *\li	'targetp' points to a NULL dns_view_t *.
 *
 * Ensures:
 *
 *\li	*targetp is attached to source.
 *
 * \li	While *targetp is attached, the view will not be freed.
 */

void
dns_view_weakdetach(dns_view_t **targetp);
/*%<
 * Detach '*viewp' from its view.
 *
 * Requires:
 *
 *\li	'viewp' points to a valid dns_view_t *.
 *
 * Ensures:
 *
 *\li	*viewp is NULL.
 */

isc_result_t
dns_view_createzonetable(dns_view_t *view);
/*%<
 * Create a zonetable for the view.
 *
 * Requires:
 *
 *\li	'view' is a valid, unfrozen view.
 *
 *\li	'view' does not have a zonetable already.
 *
 * Returns:
 *
 *\li   	#ISC_R_SUCCESS
 *
 *\li	Any error that dns_zt_create() can return.
 */

isc_result_t
dns_view_createresolver(dns_view_t *view,
			isc_taskmgr_t *taskmgr,
			unsigned int ntasks, unsigned int ndisp,
			isc_socketmgr_t *socketmgr,
			isc_timermgr_t *timermgr,
			unsigned int options,
			dns_dispatchmgr_t *dispatchmgr,
			dns_dispatch_t *dispatchv4,
			dns_dispatch_t *dispatchv6);
/*%<
 * Create a resolver and address database for the view.
 *
 * Requires:
 *
 *\li	'view' is a valid, unfrozen view.
 *
 *\li	'view' does not have a resolver already.
 *
 *\li	The requirements of dns_resolver_create() apply to 'taskmgr',
 *	'ntasks', 'socketmgr', 'timermgr', 'options', 'dispatchv4', and
 *	'dispatchv6'.
 *
 * Returns:
 *
 *\li   	#ISC_R_SUCCESS
 *
 *\li	Any error that dns_resolver_create() can return.
 */

void
dns_view_setcache(dns_view_t *view, dns_cache_t *cache, bool shared);
/*%<
 * Set the view's cache database.  If 'shared' is true, this means the cache
 * is created by another view and is shared with that view.  dns_view_setcache()
 * is a backward compatible version equivalent to setcache2(..., false).
 *
 * Requires:
 *
 *\li	'view' is a valid, unfrozen view.
 *
 *\li	'cache' is a valid cache.
 *
 * Ensures:
 *
 * \li    	The cache of 'view' is 'cached.
 *
 *\li	If this is not the first call to dns_view_setcache() for this
 *	view, then previously set cache is detached.
 */

void
dns_view_sethints(dns_view_t *view, dns_db_t *hints);
/*%<
 * Set the view's hints database.
 *
 * Requires:
 *
 *\li	'view' is a valid, unfrozen view, whose hints database has not been
 *	set.
 *
 *\li	'hints' is a valid zone database.
 *
 * Ensures:
 *
 * \li    	The hints database of 'view' is 'hints'.
 */

void
dns_view_setkeyring(dns_view_t *view, dns_tsig_keyring_t *ring);
void
dns_view_setdynamickeyring(dns_view_t *view, dns_tsig_keyring_t *ring);
/*%<
 * Set the view's static TSIG keys
 *
 * Requires:
 *
 *   \li   'view' is a valid, unfrozen view, whose static TSIG keyring has not
 *	been set.
 *
 *\li      'ring' is a valid TSIG keyring
 *
 * Ensures:
 *
 *\li      The static TSIG keyring of 'view' is 'ring'.
 */

void
dns_view_getdynamickeyring(dns_view_t *view, dns_tsig_keyring_t **ringp);
/*%<
 * Return the views dynamic keys.
 *
 *   \li  'view' is a valid, unfrozen view.
 *   \li  'ringp' != NULL && ringp == NULL.
 */

void
dns_view_setdstport(dns_view_t *view, in_port_t dstport);
/*%<
 * Set the view's destination port.  This is the port to
 * which outgoing queries are sent.  The default is 53,
 * the standard DNS port.
 *
 * Requires:
 *
 *\li      'view' is a valid view.
 *
 *\li      'dstport' is a valid TCP/UDP port number.
 *
 * Ensures:
 *\li	External name servers will be assumed to be listening
 *	on 'dstport'.  For servers whose address has already
 *	obtained obtained at the time of the call, the view may
 *	continue to use the previously set port until the address
 *	times out from the view's address database.
 */


isc_result_t
dns_view_addzone(dns_view_t *view, dns_zone_t *zone);
/*%<
 * Add zone 'zone' to 'view'.
 *
 * Requires:
 *
 *\li	'view' is a valid, unfrozen view.
 *
 *\li	'zone' is a valid zone.
 */

void
dns_view_freeze(dns_view_t *view);
/*%<
 * Freeze view.  No changes can be made to view configuration while frozen.
 *
 * Requires:
 *
 *\li	'view' is a valid, unfrozen view.
 *
 * Ensures:
 *
 *\li	'view' is frozen.
 */

void
dns_view_thaw(dns_view_t *view);
/*%<
 * Thaw view.  This allows zones to be added or removed at runtime.  This is
 * NOT thread-safe; the caller MUST have run isc_task_exclusive() prior to
 * thawing the view.
 *
 * Requires:
 *
 *\li	'view' is a valid, frozen view.
 *
 * Ensures:
 *
 *\li	'view' is no longer frozen.
 */

isc_result_t
dns_view_find(dns_view_t *view, const dns_name_t *name, dns_rdatatype_t type,
	      isc_stdtime_t now, unsigned int options,
	      bool use_hints, bool use_static_stub,
	      dns_db_t **dbp, dns_dbnode_t **nodep, dns_name_t *foundname,
	      dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset);
/*%<
 * Find an rdataset whose owner name is 'name', and whose type is
 * 'type'.
 * In general, this function first searches view's zone and cache DBs for the
 * best match data against 'name'.  If nothing found there, and if 'use_hints'
 * is true, the view's hint DB (if configured) is searched.
 * If the view is configured with a static-stub zone which gives the longest
 * match for 'name' among the zones, however, the cache DB is not consulted
 * unless 'use_static_stub' is false (see below about this argument).
 *
 * dns_view_find() is a backward compatible version equivalent to
 * dns_view_find2() with use_static_stub argument being false.
 *
 * Notes:
 *
 *\li	See the description of dns_db_find() for information about 'options'.
 *	If the caller sets #DNS_DBFIND_GLUEOK, it must ensure that 'name'
 *	and 'type' are appropriate for glue retrieval.
 *
 *\li	If 'now' is zero, then the current time will be used.
 *
 *\li	If 'use_hints' is true, and the view has a hints database, then
 *	it will be searched last.  If the answer is found in the hints
 *	database, the result code will be DNS_R_HINT.  If the name is found
 *	in the hints database but not the type, the result code will be
 *	#DNS_R_HINTNXRRSET.
 *
 *\li	If 'use_static_stub' is false and the longest match zone for 'name'
 *	is a static-stub zone, it's ignored and the cache and/or hints will be
 *	searched.  In the majority of the cases this argument should be
 *	false.  The only known usage of this argument being true is
 *	if this search is for a "bailiwick" glue A or AAAA RRset that may
 *	best match a static-stub zone.  Consider the following example:
 *	this view is configured with a static-stub zone "example.com",
 *	and an attempt of recursive resolution needs to send a query for the
 *	zone.  In this case it's quite likely that the resolver is trying to
 *	find A/AAAA RRs for the apex name "example.com".  And, to honor the
 *	static-stub configuration it needs to return the glue RRs in the
 *	static-stub zone even if that exact RRs coming from the authoritative
 *	zone has been cached.
 *	In other general cases, the requested data is better to be
 *	authoritative, either locally configured or retrieved from an external
 *	server, and the data in the static-stub zone should better be ignored.
 *
 *\li	'foundname' must meet the requirements of dns_db_find().
 *
 *\li	If 'sigrdataset' is not NULL, and there is a SIG rdataset which
 *	covers 'type', then 'sigrdataset' will be bound to it.
 *
 * Requires:
 *
 *\li	'view' is a valid, frozen view.
 *
 *\li	'name' is valid name.
 *
 *\li	'type' is a valid dns_rdatatype_t, and is not a meta query type
 *	except dns_rdatatype_any.
 *
 *\li	dbp == NULL || *dbp == NULL
 *
 *\li	nodep == NULL || *nodep == NULL.  If nodep != NULL, dbp != NULL.
 *
 *\li	'foundname' is a valid name with a dedicated buffer or NULL.
 *
 *\li	'rdataset' is a valid, disassociated rdataset.
 *
 *\li	'sigrdataset' is NULL, or is a valid, disassociated rdataset.
 *
 * Ensures:
 *
 *\li	In successful cases, 'rdataset', and possibly 'sigrdataset', are
 *	bound to the found data.
 *
 *\li	If dbp != NULL, it points to the database containing the data.
 *
 *\li	If nodep != NULL, it points to the database node containing the data.
 *
 *\li	If foundname != NULL, it contains the full name of the found data.
 *
 * Returns:
 *
 *\li	Any result that dns_db_find() can return, with the exception of
 *	#DNS_R_DELEGATION.
 */

isc_result_t
dns_view_simplefind(dns_view_t *view, const dns_name_t *name,
		    dns_rdatatype_t type, isc_stdtime_t now,
		    unsigned int options, bool use_hints,
		    dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset);
/*%<
 * Find an rdataset whose owner name is 'name', and whose type is
 * 'type'.
 *
 * Notes:
 *
 *\li	This routine is appropriate for simple, exact-match queries of the
 *	view.  'name' must be a canonical name; there is no DNAME or CNAME
 *	processing.
 *
 *\li	See the description of dns_db_find() for information about 'options'.
 *	If the caller sets DNS_DBFIND_GLUEOK, it must ensure that 'name'
 *	and 'type' are appropriate for glue retrieval.
 *
 *\li	If 'now' is zero, then the current time will be used.
 *
 *\li	If 'use_hints' is true, and the view has a hints database, then
 *	it will be searched last.  If the answer is found in the hints
 *	database, the result code will be DNS_R_HINT.  If the name is found
 *	in the hints database but not the type, the result code will be
 *	DNS_R_HINTNXRRSET.
 *
 *\li	If 'sigrdataset' is not NULL, and there is a SIG rdataset which
 *	covers 'type', then 'sigrdataset' will be bound to it.
 *
 * Requires:
 *
 *\li	'view' is a valid, frozen view.
 *
 *\li	'name' is valid name.
 *
 *\li	'type' is a valid dns_rdatatype_t, and is not a meta query type
 *	(e.g. dns_rdatatype_any), or dns_rdatatype_rrsig.
 *
 *\li	'rdataset' is a valid, disassociated rdataset.
 *
 *\li	'sigrdataset' is NULL, or is a valid, disassociated rdataset.
 *
 * Ensures:
 *
 *\li	In successful cases, 'rdataset', and possibly 'sigrdataset', are
 *	bound to the found data.
 *
 * Returns:
 *
 *\li	#ISC_R_SUCCESS			Success; result is desired type.
 *\li	DNS_R_GLUE			Success; result is glue.
 *\li	DNS_R_HINT			Success; result is a hint.
 *\li	DNS_R_NCACHENXDOMAIN		Success; result is a ncache entry.
 *\li	DNS_R_NCACHENXRRSET		Success; result is a ncache entry.
 *\li	DNS_R_NXDOMAIN			The name does not exist.
 *\li	DNS_R_NXRRSET			The rrset does not exist.
 *\li	#ISC_R_NOTFOUND			No matching data found,
 *					or an error occurred.
 */

isc_result_t
dns_view_findzonecut(dns_view_t *view, const dns_name_t *name,
		     dns_name_t *fname, dns_name_t *dcname, isc_stdtime_t now,
		     unsigned int options,
		     bool use_hints, bool use_cache,
		     dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset);
/*%<
 * Find the best known zonecut containing 'name'.
 *
 * This uses local authority, cache, and optionally hints data.
 * No external queries are performed.
 *
 * Notes:
 *
 *\li	If 'now' is zero, then the current time will be used.
 *
 *\li	If 'use_hints' is true, and the view has a hints database, then
 *	it will be searched last.
 *
 *\li	If 'use_cache' is true, and the view has a cache, then it will be
 *	searched.
 *
 *\li	If 'sigrdataset' is not NULL, and there is a SIG rdataset which
 *	covers 'type', then 'sigrdataset' will be bound to it.
 *
 *\li	If the DNS_DBFIND_NOEXACT option is set, then the zonecut returned
 *	(if any) will be the deepest known ancestor of 'name'.
 *
 *\li	If dcname is not NULL the deepest cached name is copied to it.
 *
 * Requires:
 *
 *\li	'view' is a valid, frozen view.
 *
 *\li	'name' is valid name.
 *
 *\li	'rdataset' is a valid, disassociated rdataset.
 *
 *\li	'sigrdataset' is NULL, or is a valid, disassociated rdataset.
 *
 * Returns:
 *
 *\li	#ISC_R_SUCCESS				Success.
 *
 *\li	Many other results are possible.
 */

isc_result_t
dns_viewlist_find(dns_viewlist_t *list, const char *name,
		  dns_rdataclass_t rdclass, dns_view_t **viewp);
/*%<
 * Search for a view with name 'name' and class 'rdclass' in 'list'.
 * If found, '*viewp' is (strongly) attached to it.
 *
 * Requires:
 *
 *\li	'viewp' points to a NULL dns_view_t *.
 *
 * Returns:
 *
 *\li	#ISC_R_SUCCESS		A matching view was found.
 *\li	#ISC_R_NOTFOUND		No matching view was found.
 */

isc_result_t
dns_viewlist_findzone(dns_viewlist_t *list, const dns_name_t *name,
		      bool allclasses, dns_rdataclass_t rdclass,
		      dns_zone_t **zonep);

/*%<
 * Search zone with 'name' in view with 'rdclass' in viewlist 'list'
 * If found, zone is returned in *zonep. If allclasses is set rdclass is ignored
 *
 * Returns:
 *\li	#ISC_R_SUCCESS          A matching zone was found.
 *\li	#ISC_R_NOTFOUND         No matching zone was found.
 *\li	#ISC_R_MULTIPLE         Multiple zones with the same name were found.
 */

isc_result_t
dns_view_findzone(dns_view_t *view, const dns_name_t *name,
		  dns_zone_t **zonep);
/*%<