rdataset.c

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/*
 * Copyright (C) 2004-2012, 2014, 2015  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 1999-2003  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id$ */

/*! \file */

#include <config.h>

#include <stdlib.h>

#include <isc/buffer.h>
#include <isc/mem.h>
#include <isc/random.h>
#include <isc/serial.h>
#include <isc/util.h>

#include <dns/compress.h>
#include <dns/fixedname.h>
#include <dns/name.h>
#include <dns/ncache.h>
#include <dns/rdata.h>
#include <dns/rdataset.h>

static const char *trustnames[] = {
        "none",
        "pending-additional",
        "pending-answer",
        "additional",
        "glue",
        "answer",
        "authauthority",
        "authanswer",
        "secure",
        "local" /* aka ultimate */
};

const char *
dns_trust_totext(dns_trust_t trust) {
        if (trust >= sizeof(trustnames)/sizeof(*trustnames))
                return ("bad");
        return (trustnames[trust]);
}

void
dns_rdataset_init(dns_rdataset_t *rdataset) {

        /*
         * Make 'rdataset' a valid, disassociated rdataset.
         */

        REQUIRE(rdataset != NULL);

        rdataset->magic = DNS_RDATASET_MAGIC;
        rdataset->methods = NULL;
        ISC_LINK_INIT(rdataset, link);
        rdataset->rdclass = 0;
        rdataset->type = 0;
        rdataset->ttl = 0;
        rdataset->trust = 0;
        rdataset->covers = 0;
        rdataset->attributes = 0;
        rdataset->count = ISC_UINT32_MAX;
        rdataset->private1 = NULL;
        rdataset->private2 = NULL;
        rdataset->private3 = NULL;
        rdataset->privateuint4 = 0;
        rdataset->private5 = NULL;
        rdataset->private6 = NULL;
        rdataset->private7 = NULL;
        rdataset->resign = 0;
}

void
dns_rdataset_invalidate(dns_rdataset_t *rdataset) {

        /*
         * Invalidate 'rdataset'.
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods == NULL);

        rdataset->magic = 0;
        ISC_LINK_INIT(rdataset, link);
        rdataset->rdclass = 0;
        rdataset->type = 0;
        rdataset->ttl = 0;
        rdataset->trust = 0;
        rdataset->covers = 0;
        rdataset->attributes = 0;
        rdataset->count = ISC_UINT32_MAX;
        rdataset->private1 = NULL;
        rdataset->private2 = NULL;
        rdataset->private3 = NULL;
        rdataset->privateuint4 = 0;
        rdataset->private5 = NULL;
}

void
dns_rdataset_disassociate(dns_rdataset_t *rdataset) {

        /*
         * Disassociate 'rdataset' from its rdata, allowing it to be reused.
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        (rdataset->methods->disassociate)(rdataset);
        rdataset->methods = NULL;
        ISC_LINK_INIT(rdataset, link);
        rdataset->rdclass = 0;
        rdataset->type = 0;
        rdataset->ttl = 0;
        rdataset->trust = 0;
        rdataset->covers = 0;
        rdataset->attributes = 0;
        rdataset->count = ISC_UINT32_MAX;
        rdataset->private1 = NULL;
        rdataset->private2 = NULL;
        rdataset->private3 = NULL;
        rdataset->privateuint4 = 0;
        rdataset->private5 = NULL;
        rdataset->private6 = NULL;
}

isc_boolean_t
dns_rdataset_isassociated(dns_rdataset_t *rdataset) {
        /*
         * Is 'rdataset' associated?
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));

        if (rdataset->methods != NULL)
                return (ISC_TRUE);

        return (ISC_FALSE);
}

static void
question_disassociate(dns_rdataset_t *rdataset) {
        UNUSED(rdataset);
}

static isc_result_t
question_cursor(dns_rdataset_t *rdataset) {
        UNUSED(rdataset);

        return (ISC_R_NOMORE);
}

static void
question_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
        /*
         * This routine should never be called.
         */
        UNUSED(rdataset);
        UNUSED(rdata);

        REQUIRE(0);
}

static void
question_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
        *target = *source;
}

static unsigned int
question_count(dns_rdataset_t *rdataset) {
        /*
         * This routine should never be called.
         */
        UNUSED(rdataset);
        REQUIRE(0);

        return (0);
}

static dns_rdatasetmethods_t question_methods = {
        question_disassociate,
        question_cursor,
        question_cursor,
        question_current,
        question_clone,
        question_count,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL,
        NULL
};

void
dns_rdataset_makequestion(dns_rdataset_t *rdataset, dns_rdataclass_t rdclass,
                          dns_rdatatype_t type)
{

        /*
         * Make 'rdataset' a valid, associated, question rdataset, with a
         * question class of 'rdclass' and type 'type'.
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods == NULL);

        rdataset->methods = &question_methods;
        rdataset->rdclass = rdclass;
        rdataset->type = type;
        rdataset->attributes |= DNS_RDATASETATTR_QUESTION;
}

unsigned int
dns_rdataset_count(dns_rdataset_t *rdataset) {

        /*
         * Return the number of records in 'rdataset'.
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        return ((rdataset->methods->count)(rdataset));
}

void
dns_rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) {

        /*
         * Make 'target' refer to the same rdataset as 'source'.
         */

        REQUIRE(DNS_RDATASET_VALID(source));
        REQUIRE(source->methods != NULL);
        REQUIRE(DNS_RDATASET_VALID(target));
        REQUIRE(target->methods == NULL);

        (source->methods->clone)(source, target);
}

isc_result_t
dns_rdataset_first(dns_rdataset_t *rdataset) {

        /*
         * Move the rdata cursor to the first rdata in the rdataset (if any).
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        return ((rdataset->methods->first)(rdataset));
}

isc_result_t
dns_rdataset_next(dns_rdataset_t *rdataset) {

        /*
         * Move the rdata cursor to the next rdata in the rdataset (if any).
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        return ((rdataset->methods->next)(rdataset));
}

void
dns_rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {

        /*
         * Make 'rdata' refer to the current rdata.
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        (rdataset->methods->current)(rdataset, rdata);
}

#define MAX_SHUFFLE     32
#define WANT_FIXED(r)   (((r)->attributes & DNS_RDATASETATTR_FIXEDORDER) != 0)
#define WANT_RANDOM(r)  (((r)->attributes & DNS_RDATASETATTR_RANDOMIZE) != 0)

struct towire_sort {
        int key;
        dns_rdata_t *rdata;
};

static int
towire_compare(const void *av, const void *bv) {
        const struct towire_sort *a = (const struct towire_sort *) av;
        const struct towire_sort *b = (const struct towire_sort *) bv;
        return (a->key - b->key);
}

static isc_result_t
towiresorted(dns_rdataset_t *rdataset, const dns_name_t *owner_name,
             dns_compress_t *cctx, isc_buffer_t *target,
             dns_rdatasetorderfunc_t order, const void *order_arg,
             isc_boolean_t partial, unsigned int options,
             unsigned int *countp, void **state)
{
        dns_rdata_t rdata = DNS_RDATA_INIT;
        isc_region_t r;
        isc_result_t result;
        unsigned int i, count = 0, added, choice;
        isc_buffer_t savedbuffer, rdlen, rrbuffer;
        unsigned int headlen;
        isc_boolean_t question = ISC_FALSE;
        isc_boolean_t shuffle = ISC_FALSE;
        dns_rdata_t *shuffled = NULL, shuffled_fixed[MAX_SHUFFLE];
        struct towire_sort *sorted = NULL, sorted_fixed[MAX_SHUFFLE];
        dns_fixedname_t fixed;
        dns_name_t *name;

        UNUSED(state);

        /*
         * Convert 'rdataset' to wire format, compressing names as specified
         * in cctx, and storing the result in 'target'.
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(countp != NULL);
        REQUIRE((order == NULL) == (order_arg == NULL));
        REQUIRE(cctx != NULL && cctx->mctx != NULL);

        if ((rdataset->attributes & DNS_RDATASETATTR_QUESTION) != 0) {
                question = ISC_TRUE;
                count = 1;
                result = dns_rdataset_first(rdataset);
                INSIST(result == ISC_R_NOMORE);
        } else if ((rdataset->attributes & DNS_RDATASETATTR_NEGATIVE) != 0) {
                /*
                 * This is a negative caching rdataset.
                 */
                unsigned int ncache_opts = 0;
                if ((options & DNS_RDATASETTOWIRE_OMITDNSSEC) != 0)
                        ncache_opts |= DNS_NCACHETOWIRE_OMITDNSSEC;
                return (dns_ncache_towire(rdataset, cctx, target, ncache_opts,
                                          countp));
        } else {
                count = (rdataset->methods->count)(rdataset);
                result = dns_rdataset_first(rdataset);
                if (result == ISC_R_NOMORE)
                        return (ISC_R_SUCCESS);
                if (result != ISC_R_SUCCESS)
                        return (result);
        }

        /*
         * Do we want to shuffle this answer?
         */
        if (!question && count > 1 &&
            (!WANT_FIXED(rdataset) || order != NULL) &&
            rdataset->type != dns_rdatatype_rrsig)
                shuffle = ISC_TRUE;

        if (shuffle && count > MAX_SHUFFLE) {
                shuffled = isc_mem_get(cctx->mctx, count * sizeof(*shuffled));
                sorted = isc_mem_get(cctx->mctx, count * sizeof(*sorted));
                if (shuffled == NULL || sorted == NULL)
                        shuffle = ISC_FALSE;
        } else {
                shuffled = shuffled_fixed;
                sorted = sorted_fixed;
        }

        if (shuffle) {
                /*
                 * First we get handles to all of the rdata.
                 */
                i = 0;
                do {
                        INSIST(i < count);
                        dns_rdata_init(&shuffled[i]);
                        dns_rdataset_current(rdataset, &shuffled[i]);
                        i++;
                        result = dns_rdataset_next(rdataset);
                } while (result == ISC_R_SUCCESS);
                if (result != ISC_R_NOMORE)
                        goto cleanup;
                INSIST(i == count);

                /*
                 * Now we shuffle.
                 */
                if (WANT_FIXED(rdataset)) {
                        /*
                         * 'Fixed' order.
                         */
                        INSIST(order != NULL);
                        for (i = 0; i < count; i++) {
                                sorted[i].key = (*order)(&shuffled[i],
                                                         order_arg);
                                sorted[i].rdata = &shuffled[i];
                        }
                } else if (WANT_RANDOM(rdataset)) {
                        /*
                         * 'Random' order.
                         */
                        for (i = 0; i < count; i++) {
                                isc_uint32_t val;

                                isc_random_get(&val);
                                choice = i + (val % (count - i));
                                rdata = shuffled[i];
                                shuffled[i] = shuffled[choice];
                                shuffled[choice] = rdata;
                                if (order != NULL)
                                        sorted[i].key = (*order)(&shuffled[i],
                                                                 order_arg);
                                else
                                        sorted[i].key = 0; /* Unused */
                                sorted[i].rdata = &shuffled[i];
                        }
                } else {
                        /*
                         * "Cyclic" order.
                         */
                        isc_uint32_t val;
                        unsigned int j;

                        val = rdataset->count;
                        if (val == ISC_UINT32_MAX)
                                isc_random_get(&val);
                        j = val % count;
                        for (i = 0; i < count; i++) {
                                if (order != NULL)
                                        sorted[i].key = (*order)(&shuffled[j],
                                                                 order_arg);
                                else
                                        sorted[i].key = 0; /* Unused */
                                sorted[i].rdata = &shuffled[j];
                                j++;
                                if (j == count)
                                        j = 0; /* Wrap around. */
                        }
                }

                /*
                 * Sorted order.
                 */
                if (order != NULL)
                        qsort(sorted, count, sizeof(sorted[0]),
                              towire_compare);
        }

        savedbuffer = *target;
        i = 0;
        added = 0;

        dns_fixedname_init(&fixed);
        name = dns_fixedname_name(&fixed);
        dns_name_copy(owner_name, name, NULL);
        dns_rdataset_getownercase(rdataset, name);

        do {
                /*
                 * Copy out the name, type, class, ttl.
                 */

                rrbuffer = *target;
                dns_compress_setmethods(cctx, DNS_COMPRESS_GLOBAL14);
                result = dns_name_towire(name, cctx, target);
                if (result != ISC_R_SUCCESS)
                        goto rollback;
                headlen = sizeof(dns_rdataclass_t) + sizeof(dns_rdatatype_t);
                if (!question)
                        headlen += sizeof(dns_ttl_t)
                                + 2;  /* XXX 2 for rdata len */
                isc_buffer_availableregion(target, &r);
                if (r.length < headlen) {
                        result = ISC_R_NOSPACE;
                        goto rollback;
                }
                isc_buffer_putuint16(target, rdataset->type);
                isc_buffer_putuint16(target, rdataset->rdclass);
                if (!question) {
                        isc_buffer_putuint32(target, rdataset->ttl);

                        /*
                         * Save space for rdlen.
                         */
                        rdlen = *target;
                        isc_buffer_add(target, 2);

                        /*
                         * Copy out the rdata
                         */
                        if (shuffle)
                                rdata = *(sorted[i].rdata);
                        else {
                                dns_rdata_reset(&rdata);
                                dns_rdataset_current(rdataset, &rdata);
                        }
                        result = dns_rdata_towire(&rdata, cctx, target);
                        if (result != ISC_R_SUCCESS)
                                goto rollback;
                        INSIST((target->used >= rdlen.used + 2) &&
                               (target->used - rdlen.used - 2 < 65536));
                        isc_buffer_putuint16(&rdlen,
                                             (isc_uint16_t)(target->used -
                                                            rdlen.used - 2));
                        added++;
                }

                if (shuffle) {
                        i++;
                        if (i == count)
                                result = ISC_R_NOMORE;
                        else
                                result = ISC_R_SUCCESS;
                } else {
                        result = dns_rdataset_next(rdataset);
                }
        } while (result == ISC_R_SUCCESS);

        if (result != ISC_R_NOMORE)
                goto rollback;

        *countp += count;

        result = ISC_R_SUCCESS;
        goto cleanup;

 rollback:
        if (partial && result == ISC_R_NOSPACE) {
                INSIST(rrbuffer.used < 65536);
                dns_compress_rollback(cctx, (isc_uint16_t)rrbuffer.used);
                *countp += added;
                *target = rrbuffer;
                goto cleanup;
        }
        INSIST(savedbuffer.used < 65536);
        dns_compress_rollback(cctx, (isc_uint16_t)savedbuffer.used);
        *countp = 0;
        *target = savedbuffer;

 cleanup:
        if (sorted != NULL && sorted != sorted_fixed)
                isc_mem_put(cctx->mctx, sorted, count * sizeof(*sorted));
        if (shuffled != NULL && shuffled != shuffled_fixed)
                isc_mem_put(cctx->mctx, shuffled, count * sizeof(*shuffled));
        return (result);
}

isc_result_t
dns_rdataset_towiresorted(dns_rdataset_t *rdataset,
                          const dns_name_t *owner_name,
                          dns_compress_t *cctx,
                          isc_buffer_t *target,
                          dns_rdatasetorderfunc_t order,
                          const void *order_arg,
                          unsigned int options,
                          unsigned int *countp)
{
        return (towiresorted(rdataset, owner_name, cctx, target,
                             order, order_arg, ISC_FALSE, options,
                             countp, NULL));
}

isc_result_t
dns_rdataset_towirepartial(dns_rdataset_t *rdataset,
                           const dns_name_t *owner_name,
                           dns_compress_t *cctx,
                           isc_buffer_t *target,
                           dns_rdatasetorderfunc_t order,
                           const void *order_arg,
                           unsigned int options,
                           unsigned int *countp,
                           void **state)
{
        REQUIRE(state == NULL); /* XXX remove when implemented */
        return (towiresorted(rdataset, owner_name, cctx, target,
                             order, order_arg, ISC_TRUE, options,
                             countp, state));
}

isc_result_t
dns_rdataset_towire(dns_rdataset_t *rdataset,
                    dns_name_t *owner_name,
                    dns_compress_t *cctx,
                    isc_buffer_t *target,
                    unsigned int options,
                    unsigned int *countp)
{
        return (towiresorted(rdataset, owner_name, cctx, target,
                             NULL, NULL, ISC_FALSE, options, countp, NULL));
}

isc_result_t
dns_rdataset_additionaldata(dns_rdataset_t *rdataset,
                            dns_additionaldatafunc_t add, void *arg)
{
        dns_rdata_t rdata = DNS_RDATA_INIT;
        isc_result_t result;

        /*
         * For each rdata in rdataset, call 'add' for each name and type in the
         * rdata which is subject to additional section processing.
         */

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE((rdataset->attributes & DNS_RDATASETATTR_QUESTION) == 0);

        result = dns_rdataset_first(rdataset);
        if (result != ISC_R_SUCCESS)
                return (result);

        do {
                dns_rdataset_current(rdataset, &rdata);
                result = dns_rdata_additionaldata(&rdata, add, arg);
                if (result == ISC_R_SUCCESS)
                        result = dns_rdataset_next(rdataset);
                dns_rdata_reset(&rdata);
        } while (result == ISC_R_SUCCESS);

        if (result != ISC_R_NOMORE)
                return (result);

        return (ISC_R_SUCCESS);
}

isc_result_t
dns_rdataset_addnoqname(dns_rdataset_t *rdataset, dns_name_t *name) {

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);
        if (rdataset->methods->addnoqname == NULL)
                return (ISC_R_NOTIMPLEMENTED);
        return((rdataset->methods->addnoqname)(rdataset, name));
}

isc_result_t
dns_rdataset_getnoqname(dns_rdataset_t *rdataset, dns_name_t *name,
                        dns_rdataset_t *neg, dns_rdataset_t *negsig)
{
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        if (rdataset->methods->getnoqname == NULL)
                return (ISC_R_NOTIMPLEMENTED);
        return((rdataset->methods->getnoqname)(rdataset, name, neg, negsig));
}

isc_result_t
dns_rdataset_addclosest(dns_rdataset_t *rdataset, dns_name_t *name) {

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);
        if (rdataset->methods->addclosest == NULL)
                return (ISC_R_NOTIMPLEMENTED);
        return((rdataset->methods->addclosest)(rdataset, name));
}

isc_result_t
dns_rdataset_getclosest(dns_rdataset_t *rdataset, dns_name_t *name,
                        dns_rdataset_t *neg, dns_rdataset_t *negsig)
{
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        if (rdataset->methods->getclosest == NULL)
                return (ISC_R_NOTIMPLEMENTED);
        return((rdataset->methods->getclosest)(rdataset, name, neg, negsig));
}

/*
 * Additional cache stuff
 */
isc_result_t
dns_rdataset_getadditional(dns_rdataset_t *rdataset,
                           dns_rdatasetadditional_t type,
                           dns_rdatatype_t qtype,
                           dns_acache_t *acache,
                           dns_zone_t **zonep,
                           dns_db_t **dbp,
                           dns_dbversion_t **versionp,
                           dns_dbnode_t **nodep,
                           dns_name_t *fname,
                           dns_message_t *msg,
                           isc_stdtime_t now)
{
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);
        REQUIRE(zonep == NULL || *zonep == NULL);
        REQUIRE(dbp != NULL && *dbp == NULL);
        REQUIRE(versionp != NULL && *versionp == NULL);
        REQUIRE(nodep != NULL && *nodep == NULL);
        REQUIRE(fname != NULL);
        REQUIRE(msg != NULL);

        if (acache != NULL && rdataset->methods->getadditional != NULL) {
                return ((rdataset->methods->getadditional)(rdataset, type,
                                                           qtype, acache,
                                                           zonep, dbp,
                                                           versionp, nodep,
                                                           fname, msg, now));
        }

        return (ISC_R_FAILURE);
}

isc_result_t
dns_rdataset_setadditional(dns_rdataset_t *rdataset,
                           dns_rdatasetadditional_t type,
                           dns_rdatatype_t qtype,
                           dns_acache_t *acache,
                           dns_zone_t *zone,
                           dns_db_t *db,
                           dns_dbversion_t *version,
                           dns_dbnode_t *node,
                           dns_name_t *fname)
{
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        if (acache != NULL && rdataset->methods->setadditional != NULL) {
                return ((rdataset->methods->setadditional)(rdataset, type,
                                                           qtype, acache, zone,
                                                           db, version,
                                                           node, fname));
        }

        return (ISC_R_FAILURE);
}

isc_result_t
dns_rdataset_putadditional(dns_acache_t *acache,
                           dns_rdataset_t *rdataset,
                           dns_rdatasetadditional_t type,
                           dns_rdatatype_t qtype)
{
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        if (acache != NULL && rdataset->methods->putadditional != NULL) {
                return ((rdataset->methods->putadditional)(acache, rdataset,
                                                           type, qtype));
        }

        return (ISC_R_FAILURE);
}

void
dns_rdataset_settrust(dns_rdataset_t *rdataset, dns_trust_t trust) {
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        if (rdataset->methods->settrust != NULL)
                (rdataset->methods->settrust)(rdataset, trust);
        else
                rdataset->trust = trust;
}

void
dns_rdataset_expire(dns_rdataset_t *rdataset) {
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        if (rdataset->methods->expire != NULL)
                (rdataset->methods->expire)(rdataset);
}

void
dns_rdataset_clearprefetch(dns_rdataset_t *rdataset) {
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        if (rdataset->methods->clearprefetch != NULL)
                (rdataset->methods->clearprefetch)(rdataset);
}

void
dns_rdataset_setownercase(dns_rdataset_t *rdataset, const dns_name_t *name) {
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        if (rdataset->methods->setownercase != NULL)
                (rdataset->methods->setownercase)(rdataset, name);
}

void
dns_rdataset_getownercase(const dns_rdataset_t *rdataset, dns_name_t *name) {
        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(rdataset->methods != NULL);

        if (rdataset->methods->getownercase != NULL)
                (rdataset->methods->getownercase)(rdataset, name);
}

void
dns_rdataset_trimttl(dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset,
                     dns_rdata_rrsig_t *rrsig, isc_stdtime_t now,
                     isc_boolean_t acceptexpired)
{
        isc_uint32_t ttl = 0;

        REQUIRE(DNS_RDATASET_VALID(rdataset));
        REQUIRE(DNS_RDATASET_VALID(sigrdataset));
        REQUIRE(rrsig != NULL);

        /*
         * If we accept expired RRsets keep them for no more than 120 seconds.
         */
        if (acceptexpired &&
            (isc_serial_le(rrsig->timeexpire, ((now + 120) & 0xffffffff)) ||
             isc_serial_le(rrsig->timeexpire, now)))
                ttl = 120;
        else if (isc_serial_ge(rrsig->timeexpire, now))
                ttl = rrsig->timeexpire - now;

        ttl = ISC_MIN(ISC_MIN(rdataset->ttl, sigrdataset->ttl),
                      ISC_MIN(rrsig->originalttl, ttl));
        rdataset->ttl = ttl;
        sigrdataset->ttl = ttl;
}

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