lib/dns/rdataset.c

	rdataset.c revision 80b782f356f0692c11b4e52e8dd46ec41704e5a2
/*
 * Copyright (C) 1999-2002  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: rdataset.c,v 1.67 2003/02/26 23:52:29 marka Exp $ */

#include <config.h>

#include <stdlib.h>

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

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

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->private1 = NULL;
    rdataset->private2 = NULL;
    rdataset->private3 = NULL;
    rdataset->privateuint4 = 0;
    rdataset->private5 = NULL;
}

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->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->private1 = NULL;
    rdataset->private2 = NULL;
    rdataset->private3 = NULL;
    rdataset->privateuint4 = 0;
    rdataset->private5 = 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
};

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, dns_name_t *owner_name,
         dns_compress_t *cctx, isc_buffer_t *target,
         dns_rdatasetorderfunc_t order, 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, 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[MAX_SHUFFLE];
    struct towire_sort sorted[MAX_SHUFFLE];

    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));

    count = 0;
    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->type == 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);
    }

    /*
     * We'll only shuffle if we've got enough slots in our
     * deck.
     *
     * There's no point to shuffling SIGs.
     */
    if (!question &&
        count > 1 &&
        (!WANT_FIXED(rdataset) || order != NULL) &&
        count <= MAX_SHUFFLE &&
        rdataset->type != dns_rdatatype_sig)
    {
        shuffle = ISC_TRUE;
        /*
         * 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)
            return (result);
        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++) {
                dns_rdata_t rdata;
                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;

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

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

        rrbuffer = *target;
        dns_compress_setmethods(cctx, DNS_COMPRESS_GLOBAL14);
        result = dns_name_towire(owner_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;

    return (ISC_R_SUCCESS);

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

    return (result);
}

isc_result_t
dns_rdataset_towiresorted(dns_rdataset_t *rdataset,
              dns_name_t *owner_name,
              dns_compress_t *cctx,
              isc_buffer_t *target,
              dns_rdatasetorderfunc_t order,
              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,
               dns_name_t *owner_name,
               dns_compress_t *cctx,
               isc_buffer_t *target,
               dns_rdatasetorderfunc_t order,
               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);
}