lib/dns/ds.c

/*
 * Copyright (C) 2004-2007, 2012  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2002, 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 <string.h>

#include <isc/buffer.h>
#include <isc/region.h>
#include <isc/sha1.h>
#include <isc/sha2.h>
#include <isc/util.h>

#include <dns/ds.h>
#include <dns/fixedname.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdatastruct.h>
#include <dns/result.h>

#include <dst/dst.h>

isc_result_t
dns_ds_buildrdata(dns_name_t *owner, dns_rdata_t *key,
          unsigned int digest_type, unsigned char *buffer,
          dns_rdata_t *rdata)
{
    dns_fixedname_t fname;
    dns_name_t *name;
    unsigned char digest[ISC_SHA256_DIGESTLENGTH];
    isc_region_t r;
    isc_buffer_t b;
    dns_rdata_ds_t ds;

    REQUIRE(key != NULL);
    REQUIRE(key->type == dns_rdatatype_dnskey);

    if (!dns_ds_digest_supported(digest_type))
        return (ISC_R_NOTIMPLEMENTED);

    dns_fixedname_init(&fname);
    name = dns_fixedname_name(&fname);
    (void)dns_name_downcase(owner, name, NULL);

    memset(buffer, 0, DNS_DS_BUFFERSIZE);
    isc_buffer_init(&b, buffer, DNS_DS_BUFFERSIZE);

    if (digest_type == DNS_DSDIGEST_SHA1) {
        isc_sha1_t sha1;
        isc_sha1_init(&sha1);
        dns_name_toregion(name, &r);
        isc_sha1_update(&sha1, r.base, r.length);
        dns_rdata_toregion(key, &r);
        INSIST(r.length >= 4);
        isc_sha1_update(&sha1, r.base, r.length);
        isc_sha1_final(&sha1, digest);
    } else {
        isc_sha256_t sha256;
        isc_sha256_init(&sha256);
        dns_name_toregion(name, &r);
        isc_sha256_update(&sha256, r.base, r.length);
        dns_rdata_toregion(key, &r);
        INSIST(r.length >= 4);
        isc_sha256_update(&sha256, r.base, r.length);
        isc_sha256_final(digest, &sha256);
    }

    ds.mctx = NULL;
    ds.common.rdclass = key->rdclass;
    ds.common.rdtype = dns_rdatatype_ds;
    ds.algorithm = r.base[3];
    ds.key_tag = dst_region_computeid(&r, ds.algorithm);
    ds.digest_type = digest_type;
    ds.length = (digest_type == DNS_DSDIGEST_SHA1) ?
            ISC_SHA1_DIGESTLENGTH : ISC_SHA256_DIGESTLENGTH;
    ds.digest = digest;

    return (dns_rdata_fromstruct(rdata, key->rdclass, dns_rdatatype_ds,
                     &ds, &b));
}

isc_boolean_t
dns_ds_digest_supported(unsigned int digest_type) {
    return  (ISC_TF(digest_type == DNS_DSDIGEST_SHA1 ||
            digest_type == DNS_DSDIGEST_SHA256));
}