lib/dns/view.c

	view.c revision 9c3531d72aeaad6c5f01efe6a1c82023e1379e4d
/*
 * Copyright (C) 1999, 2000  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM 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: view.c,v 1.71 2000/06/22 21:54:56 tale Exp $ */

#include <config.h>

#include <isc/task.h>
#include <isc/string.h>     /* Required for HP/UX (and others?) */
#include <isc/util.h>

#include <dns/acl.h>
#include <dns/adb.h>
#include <dns/cache.h>
#include <dns/db.h>
#include <dns/events.h>
#include <dns/keytable.h>
#include <dns/peer.h>
#include <dns/rdataset.h>
#include <dns/request.h>
#include <dns/resolver.h>
#include <dns/result.h>
#include <dns/tsig.h>
#include <dns/zone.h>
#include <dns/zt.h>

#define RESSHUTDOWN(v)  (((v)->attributes & DNS_VIEWATTR_RESSHUTDOWN) != 0)
#define ADBSHUTDOWN(v)  (((v)->attributes & DNS_VIEWATTR_ADBSHUTDOWN) != 0)
#define REQSHUTDOWN(v)  (((v)->attributes & DNS_VIEWATTR_REQSHUTDOWN) != 0)

static void resolver_shutdown(isc_task_t *task, isc_event_t *event);
static void adb_shutdown(isc_task_t *task, isc_event_t *event);
static void req_shutdown(isc_task_t *task, isc_event_t *event);

isc_result_t
dns_view_create(isc_mem_t *mctx, dns_rdataclass_t rdclass,
        const char *name, dns_view_t **viewp)
{
    dns_view_t *view;
    isc_result_t result;

    /*
     * Create a view.
     */

    REQUIRE(name != NULL);
    REQUIRE(viewp != NULL && *viewp == NULL);

    view = isc_mem_get(mctx, sizeof *view);
    if (view == NULL)
        return (ISC_R_NOMEMORY);
    view->name = isc_mem_strdup(mctx, name);
    if (view->name == NULL) {
        result = ISC_R_NOMEMORY;
        goto cleanup_view;
    }
    result = isc_mutex_init(&view->lock);
    if (result != ISC_R_SUCCESS) {
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "isc_mutex_init() failed: %s",
                 isc_result_totext(result));
        result = ISC_R_UNEXPECTED;
        goto cleanup_name;
    }
    result = isc_rwlock_init(&view->conflock, 1, 1);
    if (result != ISC_R_SUCCESS) {
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "isc_rwlock_init() failed: %s",
                 isc_result_totext(result));
        result = ISC_R_UNEXPECTED;
        goto cleanup_mutex;
    }
    view->zonetable = NULL;
    result = dns_zt_create(mctx, rdclass, &view->zonetable);
    if (result != ISC_R_SUCCESS) {
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "dns_zt_create() failed: %s",
                 isc_result_totext(result));
        result = ISC_R_UNEXPECTED;
        goto cleanup_rwlock;
    }
    view->secroots = NULL;
    result = dns_keytable_create(mctx, &view->secroots);
    if (result != ISC_R_SUCCESS) {
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "dns_keytable_create() failed: %s",
                 isc_result_totext(result));
        result = ISC_R_UNEXPECTED;
        goto cleanup_zt;
    }
    view->trustedkeys = NULL;
    result = dns_keytable_create(mctx, &view->trustedkeys);
    if (result != ISC_R_SUCCESS) {
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                 "dns_keytable_create() failed: %s",
                 isc_result_totext(result));
        result = ISC_R_UNEXPECTED;
        goto cleanup_secroots;
    }

    view->cache = NULL;
    view->cachedb = NULL;
    view->hints = NULL;
    view->resolver = NULL;
    view->adb = NULL;
    view->requestmgr = NULL;
    view->mctx = mctx;
    view->rdclass = rdclass;
    view->frozen = ISC_FALSE;
    view->task = NULL;
    view->references = 1;
    view->weakrefs = 0;
    view->attributes = (DNS_VIEWATTR_RESSHUTDOWN|DNS_VIEWATTR_ADBSHUTDOWN|
                DNS_VIEWATTR_REQSHUTDOWN);
    view->statickeys = NULL;
    view->dynamickeys = NULL;
    view->matchclients = NULL;
    result = dns_tsigkeyring_create(view->mctx, &view->dynamickeys);
    if (result != ISC_R_SUCCESS)
        goto cleanup_trustedkeys;
    view->peers = NULL;

    /*
     * Initialize configuration data with default values.
     */
    view->recursion = ISC_TRUE;
    view->auth_nxdomain = ISC_FALSE; /* Was true in BIND 8 */
    view->transfer_format = dns_one_answer;
    view->queryacl = NULL;
    view->recursionacl = NULL;
    view->requestixfr = ISC_TRUE;
    view->provideixfr = ISC_TRUE;
    view->maxcachettl = 7 * 24 * 3600;
    view->maxncachettl = 3 * 3600;
    view->dstport = 53;

    result = dns_peerlist_new(view->mctx, &view->peers);
    if (result != ISC_R_SUCCESS)
        goto cleanup_dynkeys;
    ISC_LINK_INIT(view, link);
    ISC_EVENT_INIT(&view->resevent, sizeof view->resevent, 0, NULL,
               DNS_EVENT_VIEWRESSHUTDOWN, resolver_shutdown,
               view, NULL, NULL, NULL);
    ISC_EVENT_INIT(&view->adbevent, sizeof view->adbevent, 0, NULL,
               DNS_EVENT_VIEWADBSHUTDOWN, adb_shutdown,
               view, NULL, NULL, NULL);
    ISC_EVENT_INIT(&view->reqevent, sizeof view->reqevent, 0, NULL,
               DNS_EVENT_VIEWREQSHUTDOWN, req_shutdown,
               view, NULL, NULL, NULL);
    view->magic = DNS_VIEW_MAGIC;

    *viewp = view;

    return (ISC_R_SUCCESS);

 cleanup_dynkeys:
    dns_tsigkeyring_destroy(&view->dynamickeys);

 cleanup_trustedkeys:
    dns_keytable_detach(&view->trustedkeys);

 cleanup_secroots:
    dns_keytable_detach(&view->secroots);

 cleanup_zt:
    dns_zt_detach(&view->zonetable);

 cleanup_rwlock:
    isc_rwlock_destroy(&view->conflock);

 cleanup_mutex:
    isc_mutex_destroy(&view->lock);

 cleanup_name:
    isc_mem_free(mctx, view->name);

 cleanup_view:
    isc_mem_put(mctx, view, sizeof *view);

    return (result);
}

static inline void
destroy(dns_view_t *view) {
    REQUIRE(!ISC_LINK_LINKED(view, link));
    REQUIRE(view->references == 0);
    REQUIRE(view->weakrefs == 0);
    REQUIRE(RESSHUTDOWN(view));
    REQUIRE(ADBSHUTDOWN(view));
    REQUIRE(REQSHUTDOWN(view));

    if (view->peers != NULL)
        dns_peerlist_detach(&view->peers);
    if (view->dynamickeys != NULL)
        dns_tsigkeyring_destroy(&view->dynamickeys);
    if (view->statickeys != NULL)
        dns_tsigkeyring_destroy(&view->statickeys);
    if (view->adb != NULL)
        dns_adb_detach(&view->adb);
    if (view->resolver != NULL)
        dns_resolver_detach(&view->resolver);
    if (view->requestmgr != NULL)
        dns_requestmgr_detach(&view->requestmgr);
    if (view->task != NULL)
        isc_task_detach(&view->task);
    if (view->hints != NULL)
        dns_db_detach(&view->hints);
    if (view->cachedb != NULL)
        dns_db_detach(&view->cachedb);
    if (view->cache != NULL)
        dns_cache_detach(&view->cache);
    if (view->matchclients != NULL)
        dns_acl_detach(&view->matchclients);
    if (view->queryacl != NULL)
        dns_acl_detach(&view->queryacl);
    if (view->recursionacl != NULL)
        dns_acl_detach(&view->recursionacl);
    dns_keytable_detach(&view->trustedkeys);
    dns_keytable_detach(&view->secroots);
    isc_mutex_destroy(&view->lock);
    isc_mem_free(view->mctx, view->name);
    isc_mem_put(view->mctx, view, sizeof *view);
}

static isc_boolean_t
all_done(dns_view_t *view) {
    /*
     * Caller must be holding the view lock.
     */

    if (view->references == 0 && view->weakrefs == 0 &&
        RESSHUTDOWN(view) && ADBSHUTDOWN(view) && REQSHUTDOWN(view))
        return (ISC_TRUE);

    return (ISC_FALSE);
}

void
dns_view_attach(dns_view_t *source, dns_view_t **targetp) {

    REQUIRE(DNS_VIEW_VALID(source));
    REQUIRE(targetp != NULL && *targetp == NULL);

    LOCK(&source->lock);

    INSIST(source->references > 0);
    source->references++;
    INSIST(source->references != 0);

    UNLOCK(&source->lock);

    *targetp = source;
}

void
dns_view_detach(dns_view_t **viewp) {
    dns_view_t *view;
    isc_boolean_t done = ISC_FALSE;

    REQUIRE(viewp != NULL);
    view = *viewp;
    REQUIRE(DNS_VIEW_VALID(view));

    LOCK(&view->lock);

    INSIST(view->references > 0);
    view->references--;
    if (view->references == 0) {
        if (!RESSHUTDOWN(view))
            dns_resolver_shutdown(view->resolver);
        if (!ADBSHUTDOWN(view))
            dns_adb_shutdown(view->adb);
        if (!REQSHUTDOWN(view))
            dns_requestmgr_shutdown(view->requestmgr);
        dns_zt_detach(&view->zonetable);
        done = all_done(view);
    }
    UNLOCK(&view->lock);

    *viewp = NULL;

    if (done)
        destroy(view);
}

void
dns_view_weakattach(dns_view_t *source, dns_view_t **targetp) {

    REQUIRE(DNS_VIEW_VALID(source));
    REQUIRE(targetp != NULL && *targetp == NULL);

    LOCK(&source->lock);
    source->weakrefs++;
    UNLOCK(&source->lock);

    *targetp = source;
}

void
dns_view_weakdetach(dns_view_t **viewp) {
    dns_view_t *view;
    isc_boolean_t done = ISC_FALSE;

    REQUIRE(viewp != NULL);
    view = *viewp;
    REQUIRE(DNS_VIEW_VALID(view));

    LOCK(&view->lock);

    INSIST(view->weakrefs > 0);
    view->weakrefs--;
    done = all_done(view);

    UNLOCK(&view->lock);

    *viewp = NULL;

    if (done)
        destroy(view);
}

static void
resolver_shutdown(isc_task_t *task, isc_event_t *event) {
    dns_view_t *view = event->ev_arg;
    isc_boolean_t done;

    REQUIRE(event->ev_type == DNS_EVENT_VIEWRESSHUTDOWN);
    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(view->task == task);

    UNUSED(task);

    LOCK(&view->lock);

    view->attributes |= DNS_VIEWATTR_RESSHUTDOWN;
    done = all_done(view);

    UNLOCK(&view->lock);

    isc_event_free(&event);

    if (done)
        destroy(view);
}

static void
adb_shutdown(isc_task_t *task, isc_event_t *event) {
    dns_view_t *view = event->ev_arg;
    isc_boolean_t done;

    REQUIRE(event->ev_type == DNS_EVENT_VIEWADBSHUTDOWN);
    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(view->task == task);

    UNUSED(task);

    LOCK(&view->lock);

    view->attributes |= DNS_VIEWATTR_ADBSHUTDOWN;
    done = all_done(view);

    UNLOCK(&view->lock);

    isc_event_free(&event);

    if (done)
        destroy(view);
}

static void
req_shutdown(isc_task_t *task, isc_event_t *event) {
    dns_view_t *view = event->ev_arg;
    isc_boolean_t done;

    REQUIRE(event->ev_type == DNS_EVENT_VIEWREQSHUTDOWN);
    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(view->task == task);

    UNUSED(task);

    LOCK(&view->lock);

    view->attributes |= DNS_VIEWATTR_REQSHUTDOWN;
    done = all_done(view);

    UNLOCK(&view->lock);

    isc_event_free(&event);

    if (done)
        destroy(view);
}

isc_result_t
dns_view_createresolver(dns_view_t *view,
            isc_taskmgr_t *taskmgr, unsigned int ntasks,
            isc_socketmgr_t *socketmgr,
            isc_timermgr_t *timermgr,
            unsigned int options,
            dns_dispatchmgr_t *dispatchmgr,
            dns_dispatch_t *dispatchv4,
            dns_dispatch_t *dispatchv6)
{
    isc_result_t result;
    isc_event_t *event;

    /*
     * Create a resolver and address database for the view.
     */

    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(!view->frozen);
    REQUIRE(view->resolver == NULL);

    result = isc_task_create(taskmgr, 0, &view->task);
    if (result != ISC_R_SUCCESS)
        return (result);
    isc_task_setname(view->task, "view", view);

    result = dns_resolver_create(view, taskmgr, ntasks, socketmgr,
                     timermgr, options, dispatchmgr,
                     dispatchv4, dispatchv6,
                     &view->resolver);
    if (result != ISC_R_SUCCESS) {
        isc_task_detach(&view->task);
        return (result);
    }
    event = &view->resevent;
    dns_resolver_whenshutdown(view->resolver, view->task, &event);
    view->attributes &= ~DNS_VIEWATTR_RESSHUTDOWN;

    result = dns_adb_create(view->mctx, view, timermgr, taskmgr,
                &view->adb);
    if (result != ISC_R_SUCCESS) {
        dns_resolver_shutdown(view->resolver);
        return (result);
    }
    event = &view->adbevent;
    dns_adb_whenshutdown(view->adb, view->task, &event);
    view->attributes &= ~DNS_VIEWATTR_ADBSHUTDOWN;

    result = dns_requestmgr_create(view->mctx, timermgr, socketmgr,
                      dns_resolver_taskmgr(view->resolver),
                      dns_resolver_dispatchmgr(view->resolver),
                      dns_resolver_dispatchv4(view->resolver),
                      dns_resolver_dispatchv6(view->resolver),
                      &view->requestmgr);
    if (result != ISC_R_SUCCESS) {
        dns_adb_shutdown(view->adb);
        dns_resolver_shutdown(view->resolver);
        return (result);
    }
    event = &view->reqevent;
    dns_requestmgr_whenshutdown(view->requestmgr, view->task, &event);
    view->attributes &= ~DNS_VIEWATTR_REQSHUTDOWN;

    return (ISC_R_SUCCESS);
}

void
dns_view_setcache(dns_view_t *view, dns_cache_t *cache) {

    /*
     * Set the view's cache.
     */

    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(!view->frozen);

    if (view->cache != NULL) {
        dns_db_detach(&view->cachedb);
        dns_cache_detach(&view->cache);
    }
    dns_cache_attach(cache, &view->cache);
    dns_cache_attachdb(cache, &view->cachedb);
    INSIST(DNS_DB_VALID(view->cachedb));
}

void
dns_view_sethints(dns_view_t *view, dns_db_t *hints) {

    /*
     * Set the view's hints database.
     */

    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(!view->frozen);
    REQUIRE(view->hints == NULL);
    REQUIRE(dns_db_iszone(hints));

    dns_db_attach(hints, &view->hints);
}

void
dns_view_setkeyring(dns_view_t *view, dns_tsig_keyring_t *ring) {
    /*
     * Set the view's static TSIG keyring.
     */
    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(ring != NULL);
    if (view->statickeys != NULL)
        dns_tsigkeyring_destroy(&view->statickeys);
    view->statickeys = ring;
}

void
dns_view_setdstport(dns_view_t *view, in_port_t dstport) {
    REQUIRE(DNS_VIEW_VALID(view));
    view->dstport = dstport;
}

isc_result_t
dns_view_addzone(dns_view_t *view, dns_zone_t *zone) {
    isc_result_t result;

    /*
     * Add zone 'zone' to 'view'.
     */

    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(!view->frozen);

    result = dns_zt_mount(view->zonetable, zone);

    return (result);
}

void
dns_view_freeze(dns_view_t *view) {

    /*
     * Freeze view.
     */

    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(!view->frozen);

    if (view->resolver != NULL) {
        INSIST(view->cachedb != NULL);
        dns_resolver_freeze(view->resolver);
    }
    view->frozen = ISC_TRUE;
}

isc_result_t
dns_view_findzone(dns_view_t *view, dns_name_t *name, dns_zone_t **zonep) {
    isc_result_t result;

    REQUIRE(DNS_VIEW_VALID(view));

    result = dns_zt_find(view->zonetable, name, 0, NULL, zonep);
    if (result == DNS_R_PARTIALMATCH) {
        dns_zone_detach(zonep);
        result = ISC_R_NOTFOUND;
    }

    return (result);
}

isc_result_t
dns_view_find(dns_view_t *view, dns_name_t *name, dns_rdatatype_t type,
          isc_stdtime_t now, unsigned int options,
          isc_boolean_t use_hints, dns_name_t *foundname,
          dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset)
{
    isc_result_t result;
    dns_db_t *db;
    isc_boolean_t is_cache;
    dns_rdataset_t zrdataset, zsigrdataset;
    dns_zone_t *zone;

    /*
     * Find an rdataset whose owner name is 'name', and whose type is
     * 'type'.
     */

    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(view->frozen);
    REQUIRE(type != dns_rdatatype_any && type != dns_rdatatype_sig);

    /*
     * Initialize.
     */
    dns_rdataset_init(&zrdataset);
    dns_rdataset_init(&zsigrdataset);

    /*
     * Find a database to answer the query.
     */
    zone = NULL;
    db = NULL;
    result = dns_zt_find(view->zonetable, name, 0, NULL, &zone);
    if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH) {
        result = dns_zone_getdb(zone, &db);
        if (result != ISC_R_SUCCESS && view->cachedb != NULL)
            dns_db_attach(view->cachedb, &db);
        else if (result != ISC_R_SUCCESS)
            goto cleanup;
    } else if (result == ISC_R_NOTFOUND && view->cachedb != NULL)
        dns_db_attach(view->cachedb, &db);
    else
        goto cleanup;

    is_cache = dns_db_iscache(db);

 db_find:
    /*
     * Now look for an answer in the database.
     */
    result = dns_db_find(db, name, NULL, type, options,
                 now, NULL, foundname, rdataset, sigrdataset);

    if (result == DNS_R_DELEGATION ||
        result == ISC_R_NOTFOUND) {
        if (dns_rdataset_isassociated(rdataset))
            dns_rdataset_disassociate(rdataset);
        if (sigrdataset != NULL &&
            dns_rdataset_isassociated(sigrdataset))
            dns_rdataset_disassociate(sigrdataset);
        if (!is_cache) {
            if (view->cachedb != NULL) {
                /*
                 * Either the answer is in the cache, or we
                 * don't know it.
                 */
                is_cache = ISC_TRUE;
                dns_db_detach(&db);
                dns_db_attach(view->cachedb, &db);
                goto db_find;
            }
        } else {
            /*
             * We don't have the data in the cache.  If we've got
             * glue from the zone, use it.
             */
            if (dns_rdataset_isassociated(&zrdataset)) {
                dns_rdataset_clone(&zrdataset, rdataset);
                if (sigrdataset != NULL &&
                    dns_rdataset_isassociated(&zsigrdataset))
                    dns_rdataset_clone(&zsigrdataset,
                               sigrdataset);
                result = DNS_R_GLUE;
                goto cleanup;
            }
        }
        /*
         * We don't know the answer.
         */
        result = ISC_R_NOTFOUND;
    } else if (result == DNS_R_GLUE) {
        if (view->cachedb != NULL) {
            /*
             * We found an answer, but the cache may be better.
             * Remember what we've got and go look in the cache.
             */
            is_cache = ISC_TRUE;
            dns_rdataset_clone(rdataset, &zrdataset);
            dns_rdataset_disassociate(rdataset);
            if (sigrdataset != NULL &&
                dns_rdataset_isassociated(sigrdataset)) {
                dns_rdataset_clone(sigrdataset, &zsigrdataset);
                dns_rdataset_disassociate(sigrdataset);
            }
            dns_db_detach(&db);
            dns_db_attach(view->cachedb, &db);
            goto db_find;
        }
        /*
         * Otherwise, the glue is the best answer.
         */
        result = ISC_R_SUCCESS;
    }

    if (result == ISC_R_NOTFOUND && use_hints && view->hints != NULL) {
        if (dns_rdataset_isassociated(rdataset))
            dns_rdataset_disassociate(rdataset);
        if (sigrdataset != NULL &&
            dns_rdataset_isassociated(sigrdataset))
            dns_rdataset_disassociate(sigrdataset);
        result = dns_db_find(view->hints, name, NULL, type, options,
                     now, NULL, foundname,
                     rdataset, sigrdataset);
        if (result == ISC_R_SUCCESS || result == DNS_R_GLUE) {
            /*
             * We just used a hint.  Let the resolver know it
             * should consider priming.
             */
            dns_resolver_prime(view->resolver);
            result = DNS_R_HINT;
        } else if (result == DNS_R_NXDOMAIN ||
               result == DNS_R_NXRRSET)
            result = ISC_R_NOTFOUND;
    }

 cleanup:
    if (result == DNS_R_NXDOMAIN || result == DNS_R_NXRRSET) {
        /*
         * We don't care about any DNSSEC proof data in these cases.
         */
        if (dns_rdataset_isassociated(rdataset))
            dns_rdataset_disassociate(rdataset);
        if (sigrdataset != NULL &&
            dns_rdataset_isassociated(sigrdataset))
            dns_rdataset_disassociate(sigrdataset);
    }

    if (dns_rdataset_isassociated(&zrdataset)) {
        dns_rdataset_disassociate(&zrdataset);
        if (dns_rdataset_isassociated(&zsigrdataset))
            dns_rdataset_disassociate(&zsigrdataset);
    }
    if (db != NULL)
        dns_db_detach(&db);
    if (zone != NULL)
        dns_zone_detach(&zone);

    return (result);
}

isc_result_t
dns_view_simplefind(dns_view_t *view, dns_name_t *name, dns_rdatatype_t type,
            isc_stdtime_t now, unsigned int options,
            isc_boolean_t use_hints,
            dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset)
{
    isc_result_t result;
    dns_fixedname_t foundname;

    dns_fixedname_init(&foundname);
    result = dns_view_find(view, name, type, now, options, use_hints,
                   dns_fixedname_name(&foundname),
                   rdataset, sigrdataset);
    if (result == DNS_R_NXDOMAIN) {
        /*
         * The rdataset and sigrdataset of the relevant NXT record
         * may be returned, but the caller cannot use them because
         * foundname is not returned by this simplified API.  We
         * disassociate them here to prevent any misuse by the caller.
         */
        if (dns_rdataset_isassociated(rdataset))
            dns_rdataset_disassociate(rdataset);
        if (sigrdataset != NULL &&
            dns_rdataset_isassociated(sigrdataset))
            dns_rdataset_disassociate(sigrdataset);
    } else if (result != ISC_R_SUCCESS &&
           result != DNS_R_GLUE &&
           result != DNS_R_HINT &&
           result != DNS_R_NCACHENXDOMAIN &&
           result != DNS_R_NCACHENXRRSET &&
           result != DNS_R_NXRRSET &&
           result != ISC_R_NOTFOUND) {
        if (dns_rdataset_isassociated(rdataset))
            dns_rdataset_disassociate(rdataset);
        if (sigrdataset != NULL &&
            dns_rdataset_isassociated(sigrdataset))
            dns_rdataset_disassociate(sigrdataset);
        result = ISC_R_NOTFOUND;
    }

    return (result);
}

isc_result_t
dns_view_findzonecut(dns_view_t *view, dns_name_t *name, dns_name_t *fname,
             isc_stdtime_t now, unsigned int options,
             isc_boolean_t use_hints,
             dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset)
{
    isc_result_t result;
    dns_db_t *db;
    isc_boolean_t is_cache, use_zone, try_hints;
    dns_zone_t *zone;
    dns_name_t *zfname;
    dns_rdataset_t zrdataset, zsigrdataset;
    dns_fixedname_t zfixedname;

    /*
     * Find the best known zonecut containing 'name'.
     */

    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(view->frozen);

    db = NULL;
    zone = NULL;
    use_zone = ISC_FALSE;
    try_hints = ISC_FALSE;
    zfname = NULL;

    /*
     * Initialize.
     */
    dns_fixedname_init(&zfixedname);
    dns_rdataset_init(&zrdataset);
    dns_rdataset_init(&zsigrdataset);

    /*
     * Find the right database.
     */
    result = dns_zt_find(view->zonetable, name, 0, NULL, &zone);
    if (result == ISC_R_SUCCESS || result == DNS_R_PARTIALMATCH)
        result = dns_zone_getdb(zone, &db);
    if (result == ISC_R_NOTFOUND) {
        /*
         * We're not directly authoritative for this query name, nor
         * is it a subdomain of any zone for which we're
         * authoritative.
         */
        if (view->cachedb != NULL) {
            /*
             * We have a cache; try it.
             */
            dns_db_attach(view->cachedb, &db);
        } else {
            /*
             * Maybe we have hints...
             */
            try_hints = ISC_TRUE;
            goto finish;
        }
    } else if (result != ISC_R_SUCCESS) {
        /*
         * Something is broken.
         */
        goto cleanup;
    }
    is_cache = dns_db_iscache(db);

 db_find:
    /*
     * Look for the zonecut.
     */
    if (!is_cache) {
        result = dns_db_find(db, name, NULL, dns_rdatatype_ns, options,
                     now, NULL, fname, rdataset, sigrdataset);
        if (result == DNS_R_DELEGATION)
            result = ISC_R_SUCCESS;
        else if (result != ISC_R_SUCCESS)
            goto cleanup;
        if (view->cachedb != NULL && db != view->hints) {
            /*
             * We found an answer, but the cache may be better.
             */
            zfname = dns_fixedname_name(&zfixedname);
            result = dns_name_concatenate(fname, NULL, zfname,
                              NULL);
            if (result != ISC_R_SUCCESS)
                goto cleanup;
            dns_rdataset_clone(rdataset, &zrdataset);
            dns_rdataset_disassociate(rdataset);
            if (sigrdataset != NULL &&
                dns_rdataset_isassociated(sigrdataset)) {
                dns_rdataset_clone(sigrdataset, &zsigrdataset);
                dns_rdataset_disassociate(sigrdataset);
            }
            dns_db_detach(&db);
            dns_db_attach(view->cachedb, &db);
            is_cache = ISC_TRUE;
            goto db_find;
        }
    } else {
        result = dns_db_findzonecut(db, name, options, now, NULL,
                        fname, rdataset, sigrdataset);
        if (result == ISC_R_SUCCESS) {
            if (zfname != NULL &&
                !dns_name_issubdomain(fname, zfname)) {
                /*
                 * We found a zonecut in the cache, but our
                 * zone delegation is better.
                 */
                use_zone = ISC_TRUE;
            }
        } else if (result == ISC_R_NOTFOUND) {
            if (zfname != NULL) {
                /*
                 * We didn't find anything in the cache, but we
                 * have a zone delegation, so use it.
                 */
                use_zone = ISC_TRUE;
            } else {
                /*
                 * Maybe we have hints...
                 */
                try_hints = ISC_TRUE;
            }
        } else {
            /*
             * Something bad happened.
             */
            goto cleanup;
        }
    }

 finish:
    if (use_zone) {
        if (dns_rdataset_isassociated(rdataset)) {
            dns_rdataset_disassociate(rdataset);
            if (sigrdataset != NULL &&
                dns_rdataset_isassociated(sigrdataset))
                dns_rdataset_disassociate(sigrdataset);
        }
        result = dns_name_concatenate(zfname, NULL, fname, NULL);
        if (result != ISC_R_SUCCESS)
            goto cleanup;
        dns_rdataset_clone(&zrdataset, rdataset);
        if (sigrdataset != NULL &&
            dns_rdataset_isassociated(&zrdataset))
            dns_rdataset_clone(&zsigrdataset, sigrdataset);
    } else if (try_hints && use_hints && view->hints != NULL) {
        /*
         * We've found nothing so far, but we have hints.
         */
        result = dns_db_find(view->hints, dns_rootname, NULL,
                     dns_rdatatype_ns, 0, now, NULL, fname,
                     rdataset, NULL);
        if (result != ISC_R_SUCCESS) {
            /*
             * We can't even find the hints for the root
             * nameservers!
             */
            result = ISC_R_NOTFOUND;
        }
    }

 cleanup:
    if (dns_rdataset_isassociated(&zrdataset)) {
        dns_rdataset_disassociate(&zrdataset);
        if (dns_rdataset_isassociated(&zsigrdataset))
            dns_rdataset_disassociate(&zsigrdataset);
    }
    if (db != NULL)
        dns_db_detach(&db);
    if (zone != NULL)
        dns_zone_detach(&zone);

    return (result);
}

isc_result_t
dns_viewlist_find(dns_viewlist_t *list, const char *name,
          dns_rdataclass_t rdclass, dns_view_t **viewp)
{
    dns_view_t *view;

    REQUIRE(list != NULL);

    for (view = ISC_LIST_HEAD(*list);
         view != NULL;
         view = ISC_LIST_NEXT(view, link)) {
        if (strcmp(view->name, name) == 0 && view->rdclass == rdclass)
            break;
    }
    if (view == NULL)
        return (ISC_R_NOTFOUND);

    dns_view_attach(view, viewp);

    return (ISC_R_SUCCESS);
}

isc_result_t
dns_view_load(dns_view_t *view, isc_boolean_t stop) {

    REQUIRE(DNS_VIEW_VALID(view));

    return (dns_zt_load(view->zonetable, stop));
}

isc_result_t
dns_view_checksig(dns_view_t *view, isc_buffer_t *source, dns_message_t *msg) {
    REQUIRE(DNS_VIEW_VALID(view));
    REQUIRE(source != NULL);

    return dns_tsig_verify(source, msg, view->statickeys,
                   view->dynamickeys);
}