bind/lib/dns/dst_api.c

/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0 AND 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 https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

/*
 * Copyright (C) Network Associates, Inc.
 *
 * 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 AND NETWORK ASSOCIATES 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.
 */

/*! \file */

#include <inttypes.h>
#include <stdbool.h>
#include <stdlib.h>
#include <time.h>

#include <isc/buffer.h>
#include <isc/dir.h>
#include <isc/file.h>
#include <isc/fsaccess.h>
#include <isc/lex.h>
#include <isc/mem.h>
#include <isc/once.h>
#include <isc/print.h>
#include <isc/random.h>
#include <isc/refcount.h>
#include <isc/safe.h>
#include <isc/string.h>
#include <isc/time.h>
#include <isc/util.h>

#define DST_KEY_INTERNAL

#include <isc/result.h>

#include <dns/fixedname.h>
#include <dns/keyvalues.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/ttl.h>
#include <dns/types.h>

#include "dst_internal.h"

#define DST_AS_STR(t) ((t).value.as_textregion.base)

#define NEXTTOKEN(lex, opt, token)                       \
	{                                                \
		ret = isc_lex_gettoken(lex, opt, token); \
		if (ret != ISC_R_SUCCESS)                \
			goto cleanup;                    \
	}

#define NEXTTOKEN_OR_EOF(lex, opt, token)                \
	do {                                             \
		ret = isc_lex_gettoken(lex, opt, token); \
		if (ret == ISC_R_EOF)                    \
			break;                           \
		if (ret != ISC_R_SUCCESS)                \
			goto cleanup;                    \
	} while ((*token).type == isc_tokentype_eol);

#define READLINE(lex, opt, token)                        \
	do {                                             \
		ret = isc_lex_gettoken(lex, opt, token); \
		if (ret == ISC_R_EOF)                    \
			break;                           \
		if (ret != ISC_R_SUCCESS)                \
			goto cleanup;                    \
	} while ((*token).type != isc_tokentype_eol)

#define BADTOKEN()                           \
	{                                    \
		ret = ISC_R_UNEXPECTEDTOKEN; \
		goto cleanup;                \
	}

#define NUMERIC_NTAGS (DST_MAX_NUMERIC + 1)
static const char *numerictags[NUMERIC_NTAGS] = {
	"Predecessor:", "Successor:",  "MaxTTL:",    "RollPeriod:",
	"Lifetime:",	"DSPubCount:", "DSRemCount:"
};

#define BOOLEAN_NTAGS (DST_MAX_BOOLEAN + 1)
static const char *booleantags[BOOLEAN_NTAGS] = { "KSK:", "ZSK:" };

#define TIMING_NTAGS (DST_MAX_TIMES + 1)
static const char *timingtags[TIMING_NTAGS] = {
	"Generated:",	 "Published:",	  "Active:",	   "Revoked:",
	"Retired:",	 "Removed:",

	"DSPublish:",	 "SyncPublish:",  "SyncDelete:",

	"DNSKEYChange:", "ZRRSIGChange:", "KRRSIGChange:", "DSChange:",

	"DSRemoved:"
};

#define KEYSTATES_NTAGS (DST_MAX_KEYSTATES + 1)
static const char *keystatestags[KEYSTATES_NTAGS] = {
	"DNSKEYState:", "ZRRSIGState:", "KRRSIGState:", "DSState:", "GoalState:"
};

#define KEYSTATES_NVALUES 4
static const char *keystates[KEYSTATES_NVALUES] = {
	"hidden",
	"rumoured",
	"omnipresent",
	"unretentive",
};

#define STATE_ALGORITHM_STR "Algorithm:"
#define STATE_LENGTH_STR    "Length:"
#define MAX_NTAGS \
	(DST_MAX_NUMERIC + DST_MAX_BOOLEAN + DST_MAX_TIMES + DST_MAX_KEYSTATES)

static dst_func_t *dst_t_func[DST_MAX_ALGS];

static bool dst_initialized = false;

void
gss_log(int level, const char *fmt, ...) ISC_FORMAT_PRINTF(2, 3);

/*
 * Static functions.
 */
static dst_key_t *
get_key_struct(const dns_name_t *name, unsigned int alg, unsigned int flags,
	       unsigned int protocol, unsigned int bits,
	       dns_rdataclass_t rdclass, dns_ttl_t ttl, isc_mem_t *mctx);
static isc_result_t
write_public_key(const dst_key_t *key, int type, const char *directory);
static isc_result_t
write_key_state(const dst_key_t *key, int type, const char *directory);
static isc_result_t
buildfilename(dns_name_t *name, dns_keytag_t id, unsigned int alg,
	      unsigned int type, const char *directory, isc_buffer_t *out);
static isc_result_t
computeid(dst_key_t *key);
static isc_result_t
frombuffer(const dns_name_t *name, unsigned int alg, unsigned int flags,
	   unsigned int protocol, dns_rdataclass_t rdclass,
	   isc_buffer_t *source, isc_mem_t *mctx, dst_key_t **keyp);

static isc_result_t
algorithm_status(unsigned int alg);

static isc_result_t
addsuffix(char *filename, int len, const char *dirname, const char *ofilename,
	  const char *suffix);

#define RETERR(x)                            \
	do {                                 \
		result = (x);                \
		if (result != ISC_R_SUCCESS) \
			goto out;            \
	} while (0)

#define CHECKALG(alg)                       \
	do {                                \
		isc_result_t _r;            \
		_r = algorithm_status(alg); \
		if (_r != ISC_R_SUCCESS)    \
			return ((_r));      \
	} while (0);

isc_result_t
dst_lib_init(isc_mem_t *mctx, const char *engine) {
	isc_result_t result;

	REQUIRE(mctx != NULL);
	REQUIRE(!dst_initialized);

	UNUSED(engine);

	memset(dst_t_func, 0, sizeof(dst_t_func));
	RETERR(dst__hmacmd5_init(&dst_t_func[DST_ALG_HMACMD5]));
	RETERR(dst__hmacsha1_init(&dst_t_func[DST_ALG_HMACSHA1]));
	RETERR(dst__hmacsha224_init(&dst_t_func[DST_ALG_HMACSHA224]));
	RETERR(dst__hmacsha256_init(&dst_t_func[DST_ALG_HMACSHA256]));
	RETERR(dst__hmacsha384_init(&dst_t_func[DST_ALG_HMACSHA384]));
	RETERR(dst__hmacsha512_init(&dst_t_func[DST_ALG_HMACSHA512]));
	RETERR(dst__openssl_init(engine));
	RETERR(dst__openssldh_init(&dst_t_func[DST_ALG_DH]));
	RETERR(dst__opensslrsa_init(&dst_t_func[DST_ALG_RSASHA1],
				    DST_ALG_RSASHA1));
	RETERR(dst__opensslrsa_init(&dst_t_func[DST_ALG_NSEC3RSASHA1],
				    DST_ALG_NSEC3RSASHA1));
	RETERR(dst__opensslrsa_init(&dst_t_func[DST_ALG_RSASHA256],
				    DST_ALG_RSASHA256));
	RETERR(dst__opensslrsa_init(&dst_t_func[DST_ALG_RSASHA512],
				    DST_ALG_RSASHA512));
	RETERR(dst__opensslecdsa_init(&dst_t_func[DST_ALG_ECDSA256]));
	RETERR(dst__opensslecdsa_init(&dst_t_func[DST_ALG_ECDSA384]));
#ifdef HAVE_OPENSSL_ED25519
	RETERR(dst__openssleddsa_init(&dst_t_func[DST_ALG_ED25519]));
#endif /* ifdef HAVE_OPENSSL_ED25519 */
#ifdef HAVE_OPENSSL_ED448
	RETERR(dst__openssleddsa_init(&dst_t_func[DST_ALG_ED448]));
#endif /* ifdef HAVE_OPENSSL_ED448 */

#if HAVE_GSSAPI
	RETERR(dst__gssapi_init(&dst_t_func[DST_ALG_GSSAPI]));
#endif /* HAVE_GSSAPI */

	dst_initialized = true;
	return (ISC_R_SUCCESS);

out:
	/* avoid immediate crash! */
	dst_initialized = true;
	dst_lib_destroy();
	return (result);
}

void
dst_lib_destroy(void) {
	int i;
	RUNTIME_CHECK(dst_initialized);
	dst_initialized = false;

	for (i = 0; i < DST_MAX_ALGS; i++) {
		if (dst_t_func[i] != NULL && dst_t_func[i]->cleanup != NULL) {
			dst_t_func[i]->cleanup();
		}
	}
	dst__openssl_destroy();
}

bool
dst_algorithm_supported(unsigned int alg) {
	REQUIRE(dst_initialized);

	if (alg >= DST_MAX_ALGS || dst_t_func[alg] == NULL) {
		return (false);
	}
	return (true);
}

bool
dst_ds_digest_supported(unsigned int digest_type) {
	return (digest_type == DNS_DSDIGEST_SHA1 ||
		digest_type == DNS_DSDIGEST_SHA256 ||
		digest_type == DNS_DSDIGEST_SHA384);
}

isc_result_t
dst_context_create(dst_key_t *key, isc_mem_t *mctx, isc_logcategory_t *category,
		   bool useforsigning, int maxbits, dst_context_t **dctxp) {
	dst_context_t *dctx;
	isc_result_t result;

	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key));
	REQUIRE(mctx != NULL);
	REQUIRE(dctxp != NULL && *dctxp == NULL);

	if (key->func->createctx == NULL && key->func->createctx2 == NULL) {
		return (DST_R_UNSUPPORTEDALG);
	}
	if (key->keydata.generic == NULL) {
		return (DST_R_NULLKEY);
	}

	dctx = isc_mem_get(mctx, sizeof(*dctx));
	*dctx = (dst_context_t){
		.category = category,
		.use = (useforsigning) ? DO_SIGN : DO_VERIFY,
	};

	dst_key_attach(key, &dctx->key);
	isc_mem_attach(mctx, &dctx->mctx);
	if (key->func->createctx2 != NULL) {
		result = key->func->createctx2(key, maxbits, dctx);
	} else {
		result = key->func->createctx(key, dctx);
	}
	if (result != ISC_R_SUCCESS) {
		if (dctx->key != NULL) {
			dst_key_free(&dctx->key);
		}
		isc_mem_putanddetach(&dctx->mctx, dctx, sizeof(dst_context_t));
		return (result);
	}
	dctx->magic = CTX_MAGIC;
	*dctxp = dctx;
	return (ISC_R_SUCCESS);
}

void
dst_context_destroy(dst_context_t **dctxp) {
	dst_context_t *dctx;

	REQUIRE(dctxp != NULL && VALID_CTX(*dctxp));

	dctx = *dctxp;
	*dctxp = NULL;
	INSIST(dctx->key->func->destroyctx != NULL);
	dctx->key->func->destroyctx(dctx);
	if (dctx->key != NULL) {
		dst_key_free(&dctx->key);
	}
	dctx->magic = 0;
	isc_mem_putanddetach(&dctx->mctx, dctx, sizeof(dst_context_t));
}

isc_result_t
dst_context_adddata(dst_context_t *dctx, const isc_region_t *data) {
	REQUIRE(VALID_CTX(dctx));
	REQUIRE(data != NULL);
	INSIST(dctx->key->func->adddata != NULL);

	return (dctx->key->func->adddata(dctx, data));
}

isc_result_t
dst_context_sign(dst_context_t *dctx, isc_buffer_t *sig) {
	dst_key_t *key;

	REQUIRE(VALID_CTX(dctx));
	REQUIRE(sig != NULL);

	key = dctx->key;
	CHECKALG(key->key_alg);
	if (key->keydata.generic == NULL) {
		return (DST_R_NULLKEY);
	}

	if (key->func->sign == NULL) {
		return (DST_R_NOTPRIVATEKEY);
	}
	if (key->func->isprivate == NULL || !key->func->isprivate(key)) {
		return (DST_R_NOTPRIVATEKEY);
	}

	return (key->func->sign(dctx, sig));
}

isc_result_t
dst_context_verify(dst_context_t *dctx, isc_region_t *sig) {
	REQUIRE(VALID_CTX(dctx));
	REQUIRE(sig != NULL);

	CHECKALG(dctx->key->key_alg);
	if (dctx->key->keydata.generic == NULL) {
		return (DST_R_NULLKEY);
	}
	if (dctx->key->func->verify == NULL) {
		return (DST_R_NOTPUBLICKEY);
	}

	return (dctx->key->func->verify(dctx, sig));
}

isc_result_t
dst_context_verify2(dst_context_t *dctx, unsigned int maxbits,
		    isc_region_t *sig) {
	REQUIRE(VALID_CTX(dctx));
	REQUIRE(sig != NULL);

	CHECKALG(dctx->key->key_alg);
	if (dctx->key->keydata.generic == NULL) {
		return (DST_R_NULLKEY);
	}
	if (dctx->key->func->verify == NULL && dctx->key->func->verify2 == NULL)
	{
		return (DST_R_NOTPUBLICKEY);
	}

	return (dctx->key->func->verify2 != NULL
			? dctx->key->func->verify2(dctx, maxbits, sig)
			: dctx->key->func->verify(dctx, sig));
}

isc_result_t
dst_key_computesecret(const dst_key_t *pub, const dst_key_t *priv,
		      isc_buffer_t *secret) {
	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(pub) && VALID_KEY(priv));
	REQUIRE(secret != NULL);

	CHECKALG(pub->key_alg);
	CHECKALG(priv->key_alg);

	if (pub->keydata.generic == NULL || priv->keydata.generic == NULL) {
		return (DST_R_NULLKEY);
	}

	if (pub->key_alg != priv->key_alg || pub->func->computesecret == NULL ||
	    priv->func->computesecret == NULL)
	{
		return (DST_R_KEYCANNOTCOMPUTESECRET);
	}

	if (!dst_key_isprivate(priv)) {
		return (DST_R_NOTPRIVATEKEY);
	}

	return (pub->func->computesecret(pub, priv, secret));
}

isc_result_t
dst_key_tofile(const dst_key_t *key, int type, const char *directory) {
	isc_result_t ret = ISC_R_SUCCESS;

	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key));
	REQUIRE((type &
		 (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC | DST_TYPE_STATE)) != 0);

	CHECKALG(key->key_alg);

	if (key->func->tofile == NULL) {
		return (DST_R_UNSUPPORTEDALG);
	}

	if ((type & DST_TYPE_PUBLIC) != 0) {
		ret = write_public_key(key, type, directory);
		if (ret != ISC_R_SUCCESS) {
			return (ret);
		}
	}

	if ((type & DST_TYPE_STATE) != 0) {
		ret = write_key_state(key, type, directory);
		if (ret != ISC_R_SUCCESS) {
			return (ret);
		}
	}

	if (((type & DST_TYPE_PRIVATE) != 0) &&
	    (key->key_flags & DNS_KEYFLAG_TYPEMASK) != DNS_KEYTYPE_NOKEY)
	{
		return (key->func->tofile(key, directory));
	}
	return (ISC_R_SUCCESS);
}

void
dst_key_setexternal(dst_key_t *key, bool value) {
	REQUIRE(VALID_KEY(key));

	key->external = value;
}

bool
dst_key_isexternal(dst_key_t *key) {
	REQUIRE(VALID_KEY(key));

	return (key->external);
}

void
dst_key_setmodified(dst_key_t *key, bool value) {
	REQUIRE(VALID_KEY(key));

	isc_mutex_lock(&key->mdlock);
	key->modified = value;
	isc_mutex_unlock(&key->mdlock);
}

bool
dst_key_ismodified(const dst_key_t *key) {
	bool modified;

	REQUIRE(VALID_KEY(key));

	isc_mutex_lock(&(((dst_key_t *)key)->mdlock));
	modified = key->modified;
	isc_mutex_unlock(&(((dst_key_t *)key)->mdlock));

	return (modified);
}

isc_result_t
dst_key_getfilename(dns_name_t *name, dns_keytag_t id, unsigned int alg,
		    int type, const char *directory, isc_mem_t *mctx,
		    isc_buffer_t *buf) {
	isc_result_t result;

	REQUIRE(dst_initialized);
	REQUIRE(dns_name_isabsolute(name));
	REQUIRE((type &
		 (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC | DST_TYPE_STATE)) != 0);
	REQUIRE(mctx != NULL);
	REQUIRE(buf != NULL);

	CHECKALG(alg);

	result = buildfilename(name, id, alg, type, directory, buf);
	if (result == ISC_R_SUCCESS) {
		if (isc_buffer_availablelength(buf) > 0) {
			isc_buffer_putuint8(buf, 0);
		} else {
			result = ISC_R_NOSPACE;
		}
	}

	return (result);
}

isc_result_t
dst_key_fromfile(dns_name_t *name, dns_keytag_t id, unsigned int alg, int type,
		 const char *directory, isc_mem_t *mctx, dst_key_t **keyp) {
	isc_result_t result;
	char filename[NAME_MAX];
	isc_buffer_t buf;
	dst_key_t *key;

	REQUIRE(dst_initialized);
	REQUIRE(dns_name_isabsolute(name));
	REQUIRE((type & (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC)) != 0);
	REQUIRE(mctx != NULL);
	REQUIRE(keyp != NULL && *keyp == NULL);

	CHECKALG(alg);

	key = NULL;

	isc_buffer_init(&buf, filename, NAME_MAX);
	result = dst_key_getfilename(name, id, alg, type, NULL, mctx, &buf);
	if (result != ISC_R_SUCCESS) {
		goto out;
	}

	result = dst_key_fromnamedfile(filename, directory, type, mctx, &key);
	if (result != ISC_R_SUCCESS) {
		goto out;
	}

	result = computeid(key);
	if (result != ISC_R_SUCCESS) {
		goto out;
	}

	if (!dns_name_equal(name, key->key_name) || id != key->key_id ||
	    alg != key->key_alg)
	{
		result = DST_R_INVALIDPRIVATEKEY;
		goto out;
	}

	*keyp = key;
	result = ISC_R_SUCCESS;

out:
	if ((key != NULL) && (result != ISC_R_SUCCESS)) {
		dst_key_free(&key);
	}

	return (result);
}

isc_result_t
dst_key_fromnamedfile(const char *filename, const char *dirname, int type,
		      isc_mem_t *mctx, dst_key_t **keyp) {
	isc_result_t result;
	dst_key_t *pubkey = NULL, *key = NULL;
	char *newfilename = NULL, *statefilename = NULL;
	int newfilenamelen = 0, statefilenamelen = 0;
	isc_lex_t *lex = NULL;

	REQUIRE(dst_initialized);
	REQUIRE(filename != NULL);
	REQUIRE((type & (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC)) != 0);
	REQUIRE(mctx != NULL);
	REQUIRE(keyp != NULL && *keyp == NULL);

	/* If an absolute path is specified, don't use the key directory */
	if (filename[0] == '/') {
		dirname = NULL;
	}

	newfilenamelen = strlen(filename) + 5;
	if (dirname != NULL) {
		newfilenamelen += strlen(dirname) + 1;
	}
	newfilename = isc_mem_get(mctx, newfilenamelen);
	result = addsuffix(newfilename, newfilenamelen, dirname, filename,
			   ".key");
	INSIST(result == ISC_R_SUCCESS);

	RETERR(dst_key_read_public(newfilename, type, mctx, &pubkey));
	isc_mem_put(mctx, newfilename, newfilenamelen);

	/*
	 * Read the state file, if requested by type.
	 */
	if ((type & DST_TYPE_STATE) != 0) {
		statefilenamelen = strlen(filename) + 7;
		if (dirname != NULL) {
			statefilenamelen += strlen(dirname) + 1;
		}
		statefilename = isc_mem_get(mctx, statefilenamelen);
		result = addsuffix(statefilename, statefilenamelen, dirname,
				   filename, ".state");
		INSIST(result == ISC_R_SUCCESS);
	}

	pubkey->kasp = false;
	if ((type & DST_TYPE_STATE) != 0) {
		result = dst_key_read_state(statefilename, mctx, &pubkey);
		if (result == ISC_R_SUCCESS) {
			pubkey->kasp = true;
		} else if (result == ISC_R_FILENOTFOUND) {
			/* Having no state is valid. */
			result = ISC_R_SUCCESS;
		}
		RETERR(result);
	}

	if ((type & (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC)) == DST_TYPE_PUBLIC ||
	    (pubkey->key_flags & DNS_KEYFLAG_TYPEMASK) == DNS_KEYTYPE_NOKEY)
	{
		RETERR(computeid(pubkey));
		pubkey->modified = false;
		*keyp = pubkey;
		pubkey = NULL;
		goto out;
	}

	RETERR(algorithm_status(pubkey->key_alg));

	key = get_key_struct(pubkey->key_name, pubkey->key_alg,
			     pubkey->key_flags, pubkey->key_proto,
			     pubkey->key_size, pubkey->key_class,
			     pubkey->key_ttl, mctx);
	if (key == NULL) {
		RETERR(ISC_R_NOMEMORY);
	}

	if (key->func->parse == NULL) {
		RETERR(DST_R_UNSUPPORTEDALG);
	}

	newfilenamelen = strlen(filename) + 9;
	if (dirname != NULL) {
		newfilenamelen += strlen(dirname) + 1;
	}
	newfilename = isc_mem_get(mctx, newfilenamelen);
	result = addsuffix(newfilename, newfilenamelen, dirname, filename,
			   ".private");
	INSIST(result == ISC_R_SUCCESS);

	RETERR(isc_lex_create(mctx, 1500, &lex));
	RETERR(isc_lex_openfile(lex, newfilename));
	isc_mem_put(mctx, newfilename, newfilenamelen);

	RETERR(key->func->parse(key, lex, pubkey));
	isc_lex_destroy(&lex);

	key->kasp = false;
	if ((type & DST_TYPE_STATE) != 0) {
		result = dst_key_read_state(statefilename, mctx, &key);
		if (result == ISC_R_SUCCESS) {
			key->kasp = true;
		} else if (result == ISC_R_FILENOTFOUND) {
			/* Having no state is valid. */
			result = ISC_R_SUCCESS;
		}
		RETERR(result);
	}

	RETERR(computeid(key));

	if (pubkey->key_id != key->key_id) {
		RETERR(DST_R_INVALIDPRIVATEKEY);
	}

	key->modified = false;
	*keyp = key;
	key = NULL;

out:
	if (pubkey != NULL) {
		dst_key_free(&pubkey);
	}
	if (newfilename != NULL) {
		isc_mem_put(mctx, newfilename, newfilenamelen);
	}
	if (statefilename != NULL) {
		isc_mem_put(mctx, statefilename, statefilenamelen);
	}
	if (lex != NULL) {
		isc_lex_destroy(&lex);
	}
	if (key != NULL) {
		dst_key_free(&key);
	}
	return (result);
}

isc_result_t
dst_key_todns(const dst_key_t *key, isc_buffer_t *target) {
	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key));
	REQUIRE(target != NULL);

	CHECKALG(key->key_alg);

	if (key->func->todns == NULL) {
		return (DST_R_UNSUPPORTEDALG);
	}

	if (isc_buffer_availablelength(target) < 4) {
		return (ISC_R_NOSPACE);
	}
	isc_buffer_putuint16(target, (uint16_t)(key->key_flags & 0xffff));
	isc_buffer_putuint8(target, (uint8_t)key->key_proto);
	isc_buffer_putuint8(target, (uint8_t)key->key_alg);

	if ((key->key_flags & DNS_KEYFLAG_EXTENDED) != 0) {
		if (isc_buffer_availablelength(target) < 2) {
			return (ISC_R_NOSPACE);
		}
		isc_buffer_putuint16(
			target, (uint16_t)((key->key_flags >> 16) & 0xffff));
	}

	if (key->keydata.generic == NULL) { /*%< NULL KEY */
		return (ISC_R_SUCCESS);
	}

	return (key->func->todns(key, target));
}

isc_result_t
dst_key_fromdns(const dns_name_t *name, dns_rdataclass_t rdclass,
		isc_buffer_t *source, isc_mem_t *mctx, dst_key_t **keyp) {
	uint8_t alg, proto;
	uint32_t flags, extflags;
	dst_key_t *key = NULL;
	dns_keytag_t id, rid;
	isc_region_t r;
	isc_result_t result;

	REQUIRE(dst_initialized);

	isc_buffer_remainingregion(source, &r);

	if (isc_buffer_remaininglength(source) < 4) {
		return (DST_R_INVALIDPUBLICKEY);
	}
	flags = isc_buffer_getuint16(source);
	proto = isc_buffer_getuint8(source);
	alg = isc_buffer_getuint8(source);

	id = dst_region_computeid(&r);
	rid = dst_region_computerid(&r);

	if ((flags & DNS_KEYFLAG_EXTENDED) != 0) {
		if (isc_buffer_remaininglength(source) < 2) {
			return (DST_R_INVALIDPUBLICKEY);
		}
		extflags = isc_buffer_getuint16(source);
		flags |= (extflags << 16);
	}

	result = frombuffer(name, alg, flags, proto, rdclass, source, mctx,
			    &key);
	if (result != ISC_R_SUCCESS) {
		return (result);
	}
	key->key_id = id;
	key->key_rid = rid;

	*keyp = key;
	return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_frombuffer(const dns_name_t *name, unsigned int alg, unsigned int flags,
		   unsigned int protocol, dns_rdataclass_t rdclass,
		   isc_buffer_t *source, isc_mem_t *mctx, dst_key_t **keyp) {
	dst_key_t *key = NULL;
	isc_result_t result;

	REQUIRE(dst_initialized);

	result = frombuffer(name, alg, flags, protocol, rdclass, source, mctx,
			    &key);
	if (result != ISC_R_SUCCESS) {
		return (result);
	}

	result = computeid(key);
	if (result != ISC_R_SUCCESS) {
		dst_key_free(&key);
		return (result);
	}

	*keyp = key;
	return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_tobuffer(const dst_key_t *key, isc_buffer_t *target) {
	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key));
	REQUIRE(target != NULL);

	CHECKALG(key->key_alg);

	if (key->func->todns == NULL) {
		return (DST_R_UNSUPPORTEDALG);
	}

	return (key->func->todns(key, target));
}

isc_result_t
dst_key_privatefrombuffer(dst_key_t *key, isc_buffer_t *buffer) {
	isc_lex_t *lex = NULL;
	isc_result_t result = ISC_R_SUCCESS;

	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key));
	REQUIRE(!dst_key_isprivate(key));
	REQUIRE(buffer != NULL);

	if (key->func->parse == NULL) {
		RETERR(DST_R_UNSUPPORTEDALG);
	}

	RETERR(isc_lex_create(key->mctx, 1500, &lex));
	RETERR(isc_lex_openbuffer(lex, buffer));
	RETERR(key->func->parse(key, lex, NULL));
out:
	if (lex != NULL) {
		isc_lex_destroy(&lex);
	}
	return (result);
}

dns_gss_ctx_id_t
dst_key_getgssctx(const dst_key_t *key) {
	REQUIRE(key != NULL);

	return (key->keydata.gssctx);
}

isc_result_t
dst_key_fromgssapi(const dns_name_t *name, dns_gss_ctx_id_t gssctx,
		   isc_mem_t *mctx, dst_key_t **keyp, isc_region_t *intoken) {
	dst_key_t *key;
	isc_result_t result;

	REQUIRE(gssctx != NULL);
	REQUIRE(keyp != NULL && *keyp == NULL);

	key = get_key_struct(name, DST_ALG_GSSAPI, 0, DNS_KEYPROTO_DNSSEC, 0,
			     dns_rdataclass_in, 0, mctx);
	if (key == NULL) {
		return (ISC_R_NOMEMORY);
	}

	if (intoken != NULL) {
		/*
		 * Keep the token for use by external ssu rules. They may need
		 * to examine the PAC in the kerberos ticket.
		 */
		isc_buffer_allocate(key->mctx, &key->key_tkeytoken,
				    intoken->length);
		RETERR(isc_buffer_copyregion(key->key_tkeytoken, intoken));
	}

	key->keydata.gssctx = gssctx;
	*keyp = key;
	result = ISC_R_SUCCESS;
out:
	if (result != ISC_R_SUCCESS) {
		dst_key_free(&key);
	}
	return (result);
}

isc_result_t
dst_key_buildinternal(const dns_name_t *name, unsigned int alg,
		      unsigned int bits, unsigned int flags,
		      unsigned int protocol, dns_rdataclass_t rdclass,
		      void *data, isc_mem_t *mctx, dst_key_t **keyp) {
	dst_key_t *key;
	isc_result_t result;

	REQUIRE(dst_initialized);
	REQUIRE(dns_name_isabsolute(name));
	REQUIRE(mctx != NULL);
	REQUIRE(keyp != NULL && *keyp == NULL);
	REQUIRE(data != NULL);

	CHECKALG(alg);

	key = get_key_struct(name, alg, flags, protocol, bits, rdclass, 0,
			     mctx);
	if (key == NULL) {
		return (ISC_R_NOMEMORY);
	}

	key->keydata.generic = data;

	result = computeid(key);
	if (result != ISC_R_SUCCESS) {
		dst_key_free(&key);
		return (result);
	}

	*keyp = key;
	return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_fromlabel(const dns_name_t *name, int alg, unsigned int flags,
		  unsigned int protocol, dns_rdataclass_t rdclass,
		  const char *engine, const char *label, const char *pin,
		  isc_mem_t *mctx, dst_key_t **keyp) {
	dst_key_t *key;
	isc_result_t result;

	REQUIRE(dst_initialized);
	REQUIRE(dns_name_isabsolute(name));
	REQUIRE(mctx != NULL);
	REQUIRE(keyp != NULL && *keyp == NULL);
	REQUIRE(label != NULL);

	CHECKALG(alg);

	key = get_key_struct(name, alg, flags, protocol, 0, rdclass, 0, mctx);
	if (key == NULL) {
		return (ISC_R_NOMEMORY);
	}

	if (key->func->fromlabel == NULL) {
		dst_key_free(&key);
		return (DST_R_UNSUPPORTEDALG);
	}

	result = key->func->fromlabel(key, engine, label, pin);
	if (result != ISC_R_SUCCESS) {
		dst_key_free(&key);
		return (result);
	}

	result = computeid(key);
	if (result != ISC_R_SUCCESS) {
		dst_key_free(&key);
		return (result);
	}

	*keyp = key;
	return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_generate(const dns_name_t *name, unsigned int alg, unsigned int bits,
		 unsigned int param, unsigned int flags, unsigned int protocol,
		 dns_rdataclass_t rdclass, isc_mem_t *mctx, dst_key_t **keyp,
		 void (*callback)(int)) {
	dst_key_t *key;
	isc_result_t ret;

	REQUIRE(dst_initialized);
	REQUIRE(dns_name_isabsolute(name));
	REQUIRE(mctx != NULL);
	REQUIRE(keyp != NULL && *keyp == NULL);

	CHECKALG(alg);

	key = get_key_struct(name, alg, flags, protocol, bits, rdclass, 0,
			     mctx);
	if (key == NULL) {
		return (ISC_R_NOMEMORY);
	}

	if (bits == 0) { /*%< NULL KEY */
		key->key_flags |= DNS_KEYTYPE_NOKEY;
		*keyp = key;
		return (ISC_R_SUCCESS);
	}

	if (key->func->generate == NULL) {
		dst_key_free(&key);
		return (DST_R_UNSUPPORTEDALG);
	}

	ret = key->func->generate(key, param, callback);
	if (ret != ISC_R_SUCCESS) {
		dst_key_free(&key);
		return (ret);
	}

	ret = computeid(key);
	if (ret != ISC_R_SUCCESS) {
		dst_key_free(&key);
		return (ret);
	}

	*keyp = key;
	return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_getbool(const dst_key_t *key, int type, bool *valuep) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(valuep != NULL);
	REQUIRE(type <= DST_MAX_BOOLEAN);

	isc_mutex_lock(&(((dst_key_t *)key)->mdlock));
	if (!key->boolset[type]) {
		isc_mutex_unlock(&(((dst_key_t *)key)->mdlock));
		return (ISC_R_NOTFOUND);
	}
	*valuep = key->bools[type];
	isc_mutex_unlock(&(((dst_key_t *)key)->mdlock));

	return (ISC_R_SUCCESS);
}

void
dst_key_setbool(dst_key_t *key, int type, bool value) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(type <= DST_MAX_BOOLEAN);

	isc_mutex_lock(&key->mdlock);
	key->modified = key->modified || !key->boolset[type] ||
			key->bools[type] != value;
	key->bools[type] = value;
	key->boolset[type] = true;
	isc_mutex_unlock(&key->mdlock);
}

void
dst_key_unsetbool(dst_key_t *key, int type) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(type <= DST_MAX_BOOLEAN);

	isc_mutex_lock(&key->mdlock);
	key->modified = key->modified || key->boolset[type];
	key->boolset[type] = false;
	isc_mutex_unlock(&key->mdlock);
}

isc_result_t
dst_key_getnum(const dst_key_t *key, int type, uint32_t *valuep) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(valuep != NULL);
	REQUIRE(type <= DST_MAX_NUMERIC);

	isc_mutex_lock(&(((dst_key_t *)key)->mdlock));
	if (!key->numset[type]) {
		isc_mutex_unlock(&(((dst_key_t *)key)->mdlock));
		return (ISC_R_NOTFOUND);
	}
	*valuep = key->nums[type];
	isc_mutex_unlock(&(((dst_key_t *)key)->mdlock));

	return (ISC_R_SUCCESS);
}

void
dst_key_setnum(dst_key_t *key, int type, uint32_t value) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(type <= DST_MAX_NUMERIC);

	isc_mutex_lock(&key->mdlock);
	key->modified = key->modified || !key->numset[type] ||
			key->nums[type] != value;
	key->nums[type] = value;
	key->numset[type] = true;
	isc_mutex_unlock(&key->mdlock);
}

void
dst_key_unsetnum(dst_key_t *key, int type) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(type <= DST_MAX_NUMERIC);

	isc_mutex_lock(&key->mdlock);
	key->modified = key->modified || key->numset[type];
	key->numset[type] = false;
	isc_mutex_unlock(&key->mdlock);
}

isc_result_t
dst_key_gettime(const dst_key_t *key, int type, isc_stdtime_t *timep) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(timep != NULL);
	REQUIRE(type <= DST_MAX_TIMES);

	isc_mutex_lock(&(((dst_key_t *)key)->mdlock));
	if (!key->timeset[type]) {
		isc_mutex_unlock(&(((dst_key_t *)key)->mdlock));
		return (ISC_R_NOTFOUND);
	}
	*timep = key->times[type];
	isc_mutex_unlock(&(((dst_key_t *)key)->mdlock));
	return (ISC_R_SUCCESS);
}

void
dst_key_settime(dst_key_t *key, int type, isc_stdtime_t when) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(type <= DST_MAX_TIMES);

	isc_mutex_lock(&key->mdlock);
	key->modified = key->modified || !key->timeset[type] ||
			key->times[type] != when;
	key->times[type] = when;
	key->timeset[type] = true;
	isc_mutex_unlock(&key->mdlock);
}

void
dst_key_unsettime(dst_key_t *key, int type) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(type <= DST_MAX_TIMES);

	isc_mutex_lock(&key->mdlock);
	key->modified = key->modified || key->timeset[type];
	key->timeset[type] = false;
	isc_mutex_unlock(&key->mdlock);
}

isc_result_t
dst_key_getstate(const dst_key_t *key, int type, dst_key_state_t *statep) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(statep != NULL);
	REQUIRE(type <= DST_MAX_KEYSTATES);

	isc_mutex_lock(&(((dst_key_t *)key)->mdlock));
	if (!key->keystateset[type]) {
		isc_mutex_unlock(&(((dst_key_t *)key)->mdlock));
		return (ISC_R_NOTFOUND);
	}
	*statep = key->keystates[type];
	isc_mutex_unlock(&(((dst_key_t *)key)->mdlock));

	return (ISC_R_SUCCESS);
}

void
dst_key_setstate(dst_key_t *key, int type, dst_key_state_t state) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(type <= DST_MAX_KEYSTATES);

	isc_mutex_lock(&key->mdlock);
	key->modified = key->modified || !key->keystateset[type] ||
			key->keystates[type] != state;
	key->keystates[type] = state;
	key->keystateset[type] = true;
	isc_mutex_unlock(&key->mdlock);
}

void
dst_key_unsetstate(dst_key_t *key, int type) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(type <= DST_MAX_KEYSTATES);

	isc_mutex_lock(&key->mdlock);
	key->modified = key->modified || key->keystateset[type];
	key->keystateset[type] = false;
	isc_mutex_unlock(&key->mdlock);
}

isc_result_t
dst_key_getprivateformat(const dst_key_t *key, int *majorp, int *minorp) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(majorp != NULL);
	REQUIRE(minorp != NULL);
	*majorp = key->fmt_major;
	*minorp = key->fmt_minor;
	return (ISC_R_SUCCESS);
}

void
dst_key_setprivateformat(dst_key_t *key, int major, int minor) {
	REQUIRE(VALID_KEY(key));
	key->fmt_major = major;
	key->fmt_minor = minor;
}

static bool
comparekeys(const dst_key_t *key1, const dst_key_t *key2,
	    bool match_revoked_key,
	    bool (*compare)(const dst_key_t *key1, const dst_key_t *key2)) {
	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key1));
	REQUIRE(VALID_KEY(key2));

	if (key1 == key2) {
		return (true);
	}

	if (key1->key_alg != key2->key_alg) {
		return (false);
	}

	if (key1->key_id != key2->key_id) {
		if (!match_revoked_key) {
			return (false);
		}
		if ((key1->key_flags & DNS_KEYFLAG_REVOKE) ==
		    (key2->key_flags & DNS_KEYFLAG_REVOKE))
		{
			return (false);
		}
		if (key1->key_id != key2->key_rid &&
		    key1->key_rid != key2->key_id) {
			return (false);
		}
	}

	if (compare != NULL) {
		return (compare(key1, key2));
	} else {
		return (false);
	}
}

/*
 * Compares only the public portion of two keys, by converting them
 * both to wire format and comparing the results.
 */
static bool
pub_compare(const dst_key_t *key1, const dst_key_t *key2) {
	isc_result_t result;
	unsigned char buf1[DST_KEY_MAXSIZE], buf2[DST_KEY_MAXSIZE];
	isc_buffer_t b1, b2;
	isc_region_t r1, r2;

	isc_buffer_init(&b1, buf1, sizeof(buf1));
	result = dst_key_todns(key1, &b1);
	if (result != ISC_R_SUCCESS) {
		return (false);
	}
	/* Zero out flags. */
	buf1[0] = buf1[1] = 0;
	if ((key1->key_flags & DNS_KEYFLAG_EXTENDED) != 0) {
		isc_buffer_subtract(&b1, 2);
	}

	isc_buffer_init(&b2, buf2, sizeof(buf2));
	result = dst_key_todns(key2, &b2);
	if (result != ISC_R_SUCCESS) {
		return (false);
	}
	/* Zero out flags. */
	buf2[0] = buf2[1] = 0;
	if ((key2->key_flags & DNS_KEYFLAG_EXTENDED) != 0) {
		isc_buffer_subtract(&b2, 2);
	}

	isc_buffer_usedregion(&b1, &r1);
	/* Remove extended flags. */
	if ((key1->key_flags & DNS_KEYFLAG_EXTENDED) != 0) {
		memmove(&buf1[4], &buf1[6], r1.length - 6);
		r1.length -= 2;
	}

	isc_buffer_usedregion(&b2, &r2);
	/* Remove extended flags. */
	if ((key2->key_flags & DNS_KEYFLAG_EXTENDED) != 0) {
		memmove(&buf2[4], &buf2[6], r2.length - 6);
		r2.length -= 2;
	}
	return (isc_region_compare(&r1, &r2) == 0);
}

bool
dst_key_compare(const dst_key_t *key1, const dst_key_t *key2) {
	return (comparekeys(key1, key2, false, key1->func->compare));
}

bool
dst_key_pubcompare(const dst_key_t *key1, const dst_key_t *key2,
		   bool match_revoked_key) {
	return (comparekeys(key1, key2, match_revoked_key, pub_compare));
}

bool
dst_key_paramcompare(const dst_key_t *key1, const dst_key_t *key2) {
	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key1));
	REQUIRE(VALID_KEY(key2));

	if (key1 == key2) {
		return (true);
	}
	if (key1->key_alg == key2->key_alg &&
	    key1->func->paramcompare != NULL &&
	    key1->func->paramcompare(key1, key2))
	{
		return (true);
	} else {
		return (false);
	}
}

void
dst_key_attach(dst_key_t *source, dst_key_t **target) {
	REQUIRE(dst_initialized);
	REQUIRE(target != NULL && *target == NULL);
	REQUIRE(VALID_KEY(source));

	isc_refcount_increment(&source->refs);
	*target = source;
}

void
dst_key_free(dst_key_t **keyp) {
	REQUIRE(dst_initialized);
	REQUIRE(keyp != NULL && VALID_KEY(*keyp));
	dst_key_t *key = *keyp;
	*keyp = NULL;

	if (isc_refcount_decrement(&key->refs) == 1) {
		isc_refcount_destroy(&key->refs);
		isc_mem_t *mctx = key->mctx;
		if (key->keydata.generic != NULL) {
			INSIST(key->func->destroy != NULL);
			key->func->destroy(key);
		}
		if (key->engine != NULL) {
			isc_mem_free(mctx, key->engine);
		}
		if (key->label != NULL) {
			isc_mem_free(mctx, key->label);
		}
		dns_name_free(key->key_name, mctx);
		isc_mem_put(mctx, key->key_name, sizeof(dns_name_t));
		if (key->key_tkeytoken) {
			isc_buffer_free(&key->key_tkeytoken);
		}
		isc_mutex_destroy(&key->mdlock);
		isc_safe_memwipe(key, sizeof(*key));
		isc_mem_putanddetach(&mctx, key, sizeof(*key));
	}
}

bool
dst_key_isprivate(const dst_key_t *key) {
	REQUIRE(VALID_KEY(key));
	INSIST(key->func->isprivate != NULL);
	return (key->func->isprivate(key));
}

isc_result_t
dst_key_buildfilename(const dst_key_t *key, int type, const char *directory,
		      isc_buffer_t *out) {
	REQUIRE(VALID_KEY(key));
	REQUIRE(type == DST_TYPE_PRIVATE || type == DST_TYPE_PUBLIC ||
		type == DST_TYPE_STATE || type == 0);

	return (buildfilename(key->key_name, key->key_id, key->key_alg, type,
			      directory, out));
}

isc_result_t
dst_key_sigsize(const dst_key_t *key, unsigned int *n) {
	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key));
	REQUIRE(n != NULL);

	/* XXXVIX this switch statement is too sparse to gen a jump table. */
	switch (key->key_alg) {
	case DST_ALG_RSASHA1:
	case DST_ALG_NSEC3RSASHA1:
	case DST_ALG_RSASHA256:
	case DST_ALG_RSASHA512:
		*n = (key->key_size + 7) / 8;
		break;
	case DST_ALG_ECDSA256:
		*n = DNS_SIG_ECDSA256SIZE;
		break;
	case DST_ALG_ECDSA384:
		*n = DNS_SIG_ECDSA384SIZE;
		break;
	case DST_ALG_ED25519:
		*n = DNS_SIG_ED25519SIZE;
		break;
	case DST_ALG_ED448:
		*n = DNS_SIG_ED448SIZE;
		break;
	case DST_ALG_HMACMD5:
		*n = isc_md_type_get_size(ISC_MD_MD5);
		break;
	case DST_ALG_HMACSHA1:
		*n = isc_md_type_get_size(ISC_MD_SHA1);
		break;
	case DST_ALG_HMACSHA224:
		*n = isc_md_type_get_size(ISC_MD_SHA224);
		break;
	case DST_ALG_HMACSHA256:
		*n = isc_md_type_get_size(ISC_MD_SHA256);
		break;
	case DST_ALG_HMACSHA384:
		*n = isc_md_type_get_size(ISC_MD_SHA384);
		break;
	case DST_ALG_HMACSHA512:
		*n = isc_md_type_get_size(ISC_MD_SHA512);
		break;
	case DST_ALG_GSSAPI:
		*n = 128; /*%< XXX */
		break;
	case DST_ALG_DH:
	default:
		return (DST_R_UNSUPPORTEDALG);
	}
	return (ISC_R_SUCCESS);
}

isc_result_t
dst_key_secretsize(const dst_key_t *key, unsigned int *n) {
	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key));
	REQUIRE(n != NULL);

	if (key->key_alg == DST_ALG_DH) {
		*n = (key->key_size + 7) / 8;
		return (ISC_R_SUCCESS);
	}
	return (DST_R_UNSUPPORTEDALG);
}

/*%
 * Set the flags on a key, then recompute the key ID
 */
isc_result_t
dst_key_setflags(dst_key_t *key, uint32_t flags) {
	REQUIRE(VALID_KEY(key));
	key->key_flags = flags;
	return (computeid(key));
}

void
dst_key_format(const dst_key_t *key, char *cp, unsigned int size) {
	char namestr[DNS_NAME_FORMATSIZE];
	char algstr[DNS_NAME_FORMATSIZE];

	dns_name_format(dst_key_name(key), namestr, sizeof(namestr));
	dns_secalg_format((dns_secalg_t)dst_key_alg(key), algstr,
			  sizeof(algstr));
	snprintf(cp, size, "%s/%s/%d", namestr, algstr, dst_key_id(key));
}

isc_result_t
dst_key_dump(dst_key_t *key, isc_mem_t *mctx, char **buffer, int *length) {
	REQUIRE(buffer != NULL && *buffer == NULL);
	REQUIRE(length != NULL && *length == 0);
	REQUIRE(VALID_KEY(key));

	if (key->func->dump == NULL) {
		return (ISC_R_NOTIMPLEMENTED);
	}
	return (key->func->dump(key, mctx, buffer, length));
}

isc_result_t
dst_key_restore(dns_name_t *name, unsigned int alg, unsigned int flags,
		unsigned int protocol, dns_rdataclass_t rdclass,
		isc_mem_t *mctx, const char *keystr, dst_key_t **keyp) {
	isc_result_t result;
	dst_key_t *key;

	REQUIRE(dst_initialized);
	REQUIRE(keyp != NULL && *keyp == NULL);

	if (alg >= DST_MAX_ALGS || dst_t_func[alg] == NULL) {
		return (DST_R_UNSUPPORTEDALG);
	}

	if (dst_t_func[alg]->restore == NULL) {
		return (ISC_R_NOTIMPLEMENTED);
	}

	key = get_key_struct(name, alg, flags, protocol, 0, rdclass, 0, mctx);
	if (key == NULL) {
		return (ISC_R_NOMEMORY);
	}

	result = (dst_t_func[alg]->restore)(key, keystr);
	if (result == ISC_R_SUCCESS) {
		*keyp = key;
	} else {
		dst_key_free(&key);
	}

	return (result);
}

/***
 *** Static methods
 ***/

/*%
 * Allocates a key structure and fills in some of the fields.
 */
static dst_key_t *
get_key_struct(const dns_name_t *name, unsigned int alg, unsigned int flags,
	       unsigned int protocol, unsigned int bits,
	       dns_rdataclass_t rdclass, dns_ttl_t ttl, isc_mem_t *mctx) {
	dst_key_t *key;

	key = isc_mem_get(mctx, sizeof(dst_key_t));
	*key = (dst_key_t){
		.key_name = isc_mem_get(mctx, sizeof(dns_name_t)),
		.key_alg = alg,
		.key_flags = flags,
		.key_proto = protocol,
		.key_size = bits,
		.key_class = rdclass,
		.key_ttl = ttl,
		.func = dst_t_func[alg],
	};

	dns_name_init(key->key_name, NULL);
	dns_name_dup(name, mctx, key->key_name);

	isc_refcount_init(&key->refs, 1);
	isc_mem_attach(mctx, &key->mctx);

	isc_mutex_init(&key->mdlock);

	key->magic = KEY_MAGIC;
	return (key);
}

bool
dst_key_inactive(const dst_key_t *key) {
	REQUIRE(VALID_KEY(key));

	return (key->inactive);
}

void
dst_key_setinactive(dst_key_t *key, bool inactive) {
	REQUIRE(VALID_KEY(key));

	key->inactive = inactive;
}

/*%
 * Reads a public key from disk.
 */
isc_result_t
dst_key_read_public(const char *filename, int type, isc_mem_t *mctx,
		    dst_key_t **keyp) {
	u_char rdatabuf[DST_KEY_MAXSIZE];
	isc_buffer_t b;
	dns_fixedname_t name;
	isc_lex_t *lex = NULL;
	isc_token_t token;
	isc_result_t ret;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	unsigned int opt = ISC_LEXOPT_DNSMULTILINE;
	dns_rdataclass_t rdclass = dns_rdataclass_in;
	isc_lexspecials_t specials;
	uint32_t ttl = 0;
	isc_result_t result;
	dns_rdatatype_t keytype;

	/*
	 * Open the file and read its formatted contents
	 * File format:
	 *    domain.name [ttl] [class] [KEY|DNSKEY] <flags> <protocol>
	 * <algorithm> <key>
	 */

	/* 1500 should be large enough for any key */
	ret = isc_lex_create(mctx, 1500, &lex);
	if (ret != ISC_R_SUCCESS) {
		goto cleanup;
	}

	memset(specials, 0, sizeof(specials));
	specials['('] = 1;
	specials[')'] = 1;
	specials['"'] = 1;
	isc_lex_setspecials(lex, specials);
	isc_lex_setcomments(lex, ISC_LEXCOMMENT_DNSMASTERFILE);

	ret = isc_lex_openfile(lex, filename);
	if (ret != ISC_R_SUCCESS) {
		goto cleanup;
	}

	/* Read the domain name */
	NEXTTOKEN(lex, opt, &token);
	if (token.type != isc_tokentype_string) {
		BADTOKEN();
	}

	/*
	 * We don't support "@" in .key files.
	 */
	if (!strcmp(DST_AS_STR(token), "@")) {
		BADTOKEN();
	}

	dns_fixedname_init(&name);
	isc_buffer_init(&b, DST_AS_STR(token), strlen(DST_AS_STR(token)));
	isc_buffer_add(&b, strlen(DST_AS_STR(token)));
	ret = dns_name_fromtext(dns_fixedname_name(&name), &b, dns_rootname, 0,
				NULL);
	if (ret != ISC_R_SUCCESS) {
		goto cleanup;
	}

	/* Read the next word: either TTL, class, or 'KEY' */
	NEXTTOKEN(lex, opt, &token);

	if (token.type != isc_tokentype_string) {
		BADTOKEN();
	}

	/* If it's a TTL, read the next one */
	result = dns_ttl_fromtext(&token.value.as_textregion, &ttl);
	if (result == ISC_R_SUCCESS) {
		NEXTTOKEN(lex, opt, &token);
	}

	if (token.type != isc_tokentype_string) {
		BADTOKEN();
	}

	ret = dns_rdataclass_fromtext(&rdclass, &token.value.as_textregion);
	if (ret == ISC_R_SUCCESS) {
		NEXTTOKEN(lex, opt, &token);
	}

	if (token.type != isc_tokentype_string) {
		BADTOKEN();
	}

	if (strcasecmp(DST_AS_STR(token), "DNSKEY") == 0) {
		keytype = dns_rdatatype_dnskey;
	} else if (strcasecmp(DST_AS_STR(token), "KEY") == 0) {
		keytype = dns_rdatatype_key; /*%< SIG(0), TKEY */
	} else {
		BADTOKEN();
	}

	if (((type & DST_TYPE_KEY) != 0 && keytype != dns_rdatatype_key) ||
	    ((type & DST_TYPE_KEY) == 0 && keytype != dns_rdatatype_dnskey))
	{
		ret = DST_R_BADKEYTYPE;
		goto cleanup;
	}

	isc_buffer_init(&b, rdatabuf, sizeof(rdatabuf));
	ret = dns_rdata_fromtext(&rdata, rdclass, keytype, lex, NULL, false,
				 mctx, &b, NULL);
	if (ret != ISC_R_SUCCESS) {
		goto cleanup;
	}

	ret = dst_key_fromdns(dns_fixedname_name(&name), rdclass, &b, mctx,
			      keyp);
	if (ret != ISC_R_SUCCESS) {
		goto cleanup;
	}

	dst_key_setttl(*keyp, ttl);

cleanup:
	if (lex != NULL) {
		isc_lex_destroy(&lex);
	}
	return (ret);
}

static int
find_metadata(const char *s, const char *tags[], int ntags) {
	for (int i = 0; i < ntags; i++) {
		if (tags[i] != NULL && strcasecmp(s, tags[i]) == 0) {
			return (i);
		}
	}
	return (-1);
}

static int
find_numericdata(const char *s) {
	return (find_metadata(s, numerictags, NUMERIC_NTAGS));
}

static int
find_booleandata(const char *s) {
	return (find_metadata(s, booleantags, BOOLEAN_NTAGS));
}

static int
find_timingdata(const char *s) {
	return (find_metadata(s, timingtags, TIMING_NTAGS));
}

static int
find_keystatedata(const char *s) {
	return (find_metadata(s, keystatestags, KEYSTATES_NTAGS));
}

static isc_result_t
keystate_fromtext(const char *s, dst_key_state_t *state) {
	for (int i = 0; i < KEYSTATES_NVALUES; i++) {
		if (keystates[i] != NULL && strcasecmp(s, keystates[i]) == 0) {
			*state = (dst_key_state_t)i;
			return (ISC_R_SUCCESS);
		}
	}
	return (ISC_R_NOTFOUND);
}

/*%
 * Reads a key state from disk.
 */
isc_result_t
dst_key_read_state(const char *filename, isc_mem_t *mctx, dst_key_t **keyp) {
	isc_lex_t *lex = NULL;
	isc_token_t token;
	isc_result_t ret;
	unsigned int opt = ISC_LEXOPT_EOL;

	ret = isc_lex_create(mctx, 1500, &lex);
	if (ret != ISC_R_SUCCESS) {
		goto cleanup;
	}
	isc_lex_setcomments(lex, ISC_LEXCOMMENT_DNSMASTERFILE);

	ret = isc_lex_openfile(lex, filename);
	if (ret != ISC_R_SUCCESS) {
		goto cleanup;
	}

	/*
	 * Read the comment line.
	 */
	READLINE(lex, opt, &token);

	/*
	 * Read the algorithm line.
	 */
	NEXTTOKEN(lex, opt, &token);
	if (token.type != isc_tokentype_string ||
	    strcmp(DST_AS_STR(token), STATE_ALGORITHM_STR) != 0)
	{
		BADTOKEN();
	}

	NEXTTOKEN(lex, opt | ISC_LEXOPT_NUMBER, &token);
	if (token.type != isc_tokentype_number ||
	    token.value.as_ulong != (unsigned long)dst_key_alg(*keyp))
	{
		BADTOKEN();
	}

	READLINE(lex, opt, &token);

	/*
	 * Read the length line.
	 */
	NEXTTOKEN(lex, opt, &token);
	if (token.type != isc_tokentype_string ||
	    strcmp(DST_AS_STR(token), STATE_LENGTH_STR) != 0)
	{
		BADTOKEN();
	}

	NEXTTOKEN(lex, opt | ISC_LEXOPT_NUMBER, &token);
	if (token.type != isc_tokentype_number ||
	    token.value.as_ulong != (unsigned long)dst_key_size(*keyp))
	{
		BADTOKEN();
	}

	READLINE(lex, opt, &token);

	/*
	 * Read the metadata.
	 */
	for (int n = 0; n < MAX_NTAGS; n++) {
		int tag;

		NEXTTOKEN_OR_EOF(lex, opt, &token);
		if (ret == ISC_R_EOF) {
			break;
		}
		if (token.type != isc_tokentype_string) {
			BADTOKEN();
		}

		/* Numeric metadata */
		tag = find_numericdata(DST_AS_STR(token));
		if (tag >= 0) {
			INSIST(tag < NUMERIC_NTAGS);

			NEXTTOKEN(lex, opt | ISC_LEXOPT_NUMBER, &token);
			if (token.type != isc_tokentype_number) {
				BADTOKEN();
			}

			dst_key_setnum(*keyp, tag, token.value.as_ulong);
			goto next;
		}

		/* Boolean metadata */
		tag = find_booleandata(DST_AS_STR(token));
		if (tag >= 0) {
			INSIST(tag < BOOLEAN_NTAGS);

			NEXTTOKEN(lex, opt, &token);
			if (token.type != isc_tokentype_string) {
				BADTOKEN();
			}

			if (strcmp(DST_AS_STR(token), "yes") == 0) {
				dst_key_setbool(*keyp, tag, true);
			} else if (strcmp(DST_AS_STR(token), "no") == 0) {
				dst_key_setbool(*keyp, tag, false);
			} else {
				BADTOKEN();
			}
			goto next;
		}

		/* Timing metadata */
		tag = find_timingdata(DST_AS_STR(token));
		if (tag >= 0) {
			uint32_t when;

			INSIST(tag < TIMING_NTAGS);

			NEXTTOKEN(lex, opt, &token);
			if (token.type != isc_tokentype_string) {
				BADTOKEN();
			}

			ret = dns_time32_fromtext(DST_AS_STR(token), &when);
			if (ret != ISC_R_SUCCESS) {
				goto cleanup;
			}

			dst_key_settime(*keyp, tag, when);
			goto next;
		}

		/* Keystate metadata */
		tag = find_keystatedata(DST_AS_STR(token));
		if (tag >= 0) {
			dst_key_state_t state;

			INSIST(tag < KEYSTATES_NTAGS);

			NEXTTOKEN(lex, opt, &token);
			if (token.type != isc_tokentype_string) {
				BADTOKEN();
			}

			ret = keystate_fromtext(DST_AS_STR(token), &state);
			if (ret != ISC_R_SUCCESS) {
				goto cleanup;
			}

			dst_key_setstate(*keyp, tag, state);
			goto next;
		}

	next:
		READLINE(lex, opt, &token);
	}

	/* Done, successfully parsed the whole file. */
	ret = ISC_R_SUCCESS;

cleanup:
	if (lex != NULL) {
		isc_lex_destroy(&lex);
	}
	return (ret);
}

static bool
issymmetric(const dst_key_t *key) {
	REQUIRE(dst_initialized);
	REQUIRE(VALID_KEY(key));

	/* XXXVIX this switch statement is too sparse to gen a jump table. */
	switch (key->key_alg) {
	case DST_ALG_RSASHA1:
	case DST_ALG_NSEC3RSASHA1:
	case DST_ALG_RSASHA256:
	case DST_ALG_RSASHA512:
	case DST_ALG_DH:
	case DST_ALG_ECDSA256:
	case DST_ALG_ECDSA384:
	case DST_ALG_ED25519:
	case DST_ALG_ED448:
		return (false);
	case DST_ALG_HMACMD5:
	case DST_ALG_HMACSHA1:
	case DST_ALG_HMACSHA224:
	case DST_ALG_HMACSHA256:
	case DST_ALG_HMACSHA384:
	case DST_ALG_HMACSHA512:
	case DST_ALG_GSSAPI:
		return (true);
	default:
		return (false);
	}
}

/*%
 * Write key boolean metadata to a file pointer, preceded by 'tag'
 */
static void
printbool(const dst_key_t *key, int type, const char *tag, FILE *stream) {
	isc_result_t result;
	bool value = 0;

	result = dst_key_getbool(key, type, &value);
	if (result != ISC_R_SUCCESS) {
		return;
	}
	fprintf(stream, "%s: %s\n", tag, value ? "yes" : "no");
}

/*%
 * Write key numeric metadata to a file pointer, preceded by 'tag'
 */
static void
printnum(const dst_key_t *key, int type, const char *tag, FILE *stream) {
	isc_result_t result;
	uint32_t value = 0;

	result = dst_key_getnum(key, type, &value);
	if (result != ISC_R_SUCCESS) {
		return;
	}
	fprintf(stream, "%s: %u\n", tag, value);
}

/*%
 * Write key timing metadata to a file pointer, preceded by 'tag'
 */
static void
printtime(const dst_key_t *key, int type, const char *tag, FILE *stream) {
	isc_result_t result;
	char output[26]; /* Minimum buffer as per ctime_r() specification. */
	isc_stdtime_t when;
	char utc[sizeof("YYYYMMDDHHSSMM")];
	isc_buffer_t b;
	isc_region_t r;

	result = dst_key_gettime(key, type, &when);
	if (result == ISC_R_NOTFOUND) {
		return;
	}

	isc_stdtime_tostring(when, output, sizeof(output));
	isc_buffer_init(&b, utc, sizeof(utc));
	result = dns_time32_totext(when, &b);
	if (result != ISC_R_SUCCESS) {
		goto error;
	}

	isc_buffer_usedregion(&b, &r);
	fprintf(stream, "%s: %.*s (%s)\n", tag, (int)r.length, r.base, output);
	return;

error:
	fprintf(stream, "%s: (set, unable to display)\n", tag);
}

/*%
 * Write key state metadata to a file pointer, preceded by 'tag'
 */
static void
printstate(const dst_key_t *key, int type, const char *tag, FILE *stream) {
	isc_result_t result;
	dst_key_state_t value = 0;

	result = dst_key_getstate(key, type, &value);
	if (result != ISC_R_SUCCESS) {
		return;
	}
	fprintf(stream, "%s: %s\n", tag, keystates[value]);
}

/*%
 * Writes a key state to disk.
 */
static isc_result_t
write_key_state(const dst_key_t *key, int type, const char *directory) {
	FILE *fp;
	isc_buffer_t fileb;
	char filename[NAME_MAX];
	isc_result_t ret;
	isc_fsaccess_t access;

	REQUIRE(VALID_KEY(key));

	/*
	 * Make the filename.
	 */
	isc_buffer_init(&fileb, filename, sizeof(filename));
	ret = dst_key_buildfilename(key, DST_TYPE_STATE, directory, &fileb);
	if (ret != ISC_R_SUCCESS) {
		return (ret);
	}

	/*
	 * Create public key file.
	 */
	if ((fp = fopen(filename, "w")) == NULL) {
		return (DST_R_WRITEERROR);
	}

	if (issymmetric(key)) {
		access = 0;
		isc_fsaccess_add(ISC_FSACCESS_OWNER,
				 ISC_FSACCESS_READ | ISC_FSACCESS_WRITE,
				 &access);
		(void)isc_fsaccess_set(filename, access);
	}

	/* Write key state */
	if ((type & DST_TYPE_KEY) == 0) {
		fprintf(fp, "; This is the state of key %d, for ", key->key_id);
		ret = dns_name_print(key->key_name, fp);
		if (ret != ISC_R_SUCCESS) {
			fclose(fp);
			return (ret);
		}
		fputc('\n', fp);

		fprintf(fp, "Algorithm: %u\n", key->key_alg);
		fprintf(fp, "Length: %u\n", key->key_size);

		printnum(key, DST_NUM_LIFETIME, "Lifetime", fp);
		printnum(key, DST_NUM_PREDECESSOR, "Predecessor", fp);
		printnum(key, DST_NUM_SUCCESSOR, "Successor", fp);

		printbool(key, DST_BOOL_KSK, "KSK", fp);
		printbool(key, DST_BOOL_ZSK, "ZSK", fp);

		printtime(key, DST_TIME_CREATED, "Generated", fp);
		printtime(key, DST_TIME_PUBLISH, "Published", fp);
		printtime(key, DST_TIME_ACTIVATE, "Active", fp);
		printtime(key, DST_TIME_INACTIVE, "Retired", fp);
		printtime(key, DST_TIME_REVOKE, "Revoked", fp);
		printtime(key, DST_TIME_DELETE, "Removed", fp);
		printtime(key, DST_TIME_DSPUBLISH, "DSPublish", fp);
		printtime(key, DST_TIME_DSDELETE, "DSRemoved", fp);
		printtime(key, DST_TIME_SYNCPUBLISH, "PublishCDS", fp);
		printtime(key, DST_TIME_SYNCDELETE, "DeleteCDS", fp);

		printnum(key, DST_NUM_DSPUBCOUNT, "DSPubCount", fp);
		printnum(key, DST_NUM_DSDELCOUNT, "DSDelCount", fp);

		printtime(key, DST_TIME_DNSKEY, "DNSKEYChange", fp);
		printtime(key, DST_TIME_ZRRSIG, "ZRRSIGChange", fp);
		printtime(key, DST_TIME_KRRSIG, "KRRSIGChange", fp);
		printtime(key, DST_TIME_DS, "DSChange", fp);

		printstate(key, DST_KEY_DNSKEY, "DNSKEYState", fp);
		printstate(key, DST_KEY_ZRRSIG, "ZRRSIGState", fp);
		printstate(key, DST_KEY_KRRSIG, "KRRSIGState", fp);
		printstate(key, DST_KEY_DS, "DSState", fp);
		printstate(key, DST_KEY_GOAL, "GoalState", fp);
	}

	fflush(fp);
	if (ferror(fp)) {
		ret = DST_R_WRITEERROR;
	}
	fclose(fp);

	return (ret);
}

/*%
 * Writes a public key to disk in DNS format.
 */
static isc_result_t
write_public_key(const dst_key_t *key, int type, const char *directory) {
	FILE *fp;
	isc_buffer_t keyb, textb, fileb, classb;
	isc_region_t r;
	char filename[NAME_MAX];
	unsigned char key_array[DST_KEY_MAXSIZE];
	char text_array[DST_KEY_MAXTEXTSIZE];
	char class_array[10];
	isc_result_t ret;
	dns_rdata_t rdata = DNS_RDATA_INIT;
	isc_fsaccess_t access;

	REQUIRE(VALID_KEY(key));

	isc_buffer_init(&keyb, key_array, sizeof(key_array));
	isc_buffer_init(&textb, text_array, sizeof(text_array));
	isc_buffer_init(&classb, class_array, sizeof(class_array));

	ret = dst_key_todns(key, &keyb);
	if (ret != ISC_R_SUCCESS) {
		return (ret);
	}

	isc_buffer_usedregion(&keyb, &r);
	dns_rdata_fromregion(&rdata, key->key_class, dns_rdatatype_dnskey, &r);

	ret = dns_rdata_totext(&rdata, (dns_name_t *)NULL, &textb);
	if (ret != ISC_R_SUCCESS) {
		return (DST_R_INVALIDPUBLICKEY);
	}

	ret = dns_rdataclass_totext(key->key_class, &classb);
	if (ret != ISC_R_SUCCESS) {
		return (DST_R_INVALIDPUBLICKEY);
	}

	/*
	 * Make the filename.
	 */
	isc_buffer_init(&fileb, filename, sizeof(filename));
	ret = dst_key_buildfilename(key, DST_TYPE_PUBLIC, directory, &fileb);
	if (ret != ISC_R_SUCCESS) {
		return (ret);
	}

	/*
	 * Create public key file.
	 */
	if ((fp = fopen(filename, "w")) == NULL) {
		return (DST_R_WRITEERROR);
	}

	if (issymmetric(key)) {
		access = 0;
		isc_fsaccess_add(ISC_FSACCESS_OWNER,
				 ISC_FSACCESS_READ | ISC_FSACCESS_WRITE,
				 &access);
		(void)isc_fsaccess_set(filename, access);
	}

	/* Write key information in comments */
	if ((type & DST_TYPE_KEY) == 0) {
		fprintf(fp, "; This is a %s%s-signing key, keyid %d, for ",
			(key->key_flags & DNS_KEYFLAG_REVOKE) != 0 ? "revoked "
								   : "",
			(key->key_flags & DNS_KEYFLAG_KSK) != 0 ? "key"
								: "zone",
			key->key_id);
		ret = dns_name_print(key->key_name, fp);
		if (ret != ISC_R_SUCCESS) {
			fclose(fp);
			return (ret);
		}
		fputc('\n', fp);

		printtime(key, DST_TIME_CREATED, "; Created", fp);
		printtime(key, DST_TIME_PUBLISH, "; Publish", fp);
		printtime(key, DST_TIME_ACTIVATE, "; Activate", fp);
		printtime(key, DST_TIME_REVOKE, "; Revoke", fp);
		printtime(key, DST_TIME_INACTIVE, "; Inactive", fp);
		printtime(key, DST_TIME_DELETE, "; Delete", fp);
		printtime(key, DST_TIME_SYNCPUBLISH, "; SyncPublish", fp);
		printtime(key, DST_TIME_SYNCDELETE, "; SyncDelete", fp);
	}

	/* Now print the actual key */
	ret = dns_name_print(key->key_name, fp);
	fprintf(fp, " ");

	if (key->key_ttl != 0) {
		fprintf(fp, "%u ", key->key_ttl);
	}

	isc_buffer_usedregion(&classb, &r);
	if ((unsigned int)fwrite(r.base, 1, r.length, fp) != r.length) {
		ret = DST_R_WRITEERROR;
	}

	if ((type & DST_TYPE_KEY) != 0) {
		fprintf(fp, " KEY ");
	} else {
		fprintf(fp, " DNSKEY ");
	}

	isc_buffer_usedregion(&textb, &r);
	if ((unsigned int)fwrite(r.base, 1, r.length, fp) != r.length) {
		ret = DST_R_WRITEERROR;
	}

	fputc('\n', fp);
	fflush(fp);
	if (ferror(fp)) {
		ret = DST_R_WRITEERROR;
	}
	fclose(fp);

	return (ret);
}

static isc_result_t
buildfilename(dns_name_t *name, dns_keytag_t id, unsigned int alg,
	      unsigned int type, const char *directory, isc_buffer_t *out) {
	const char *suffix = "";
	isc_result_t result;

	REQUIRE(out != NULL);
	if ((type & DST_TYPE_PRIVATE) != 0) {
		suffix = ".private";
	} else if ((type & DST_TYPE_PUBLIC) != 0) {
		suffix = ".key";
	} else if ((type & DST_TYPE_STATE) != 0) {
		suffix = ".state";
	}

	if (directory != NULL) {
		if (isc_buffer_availablelength(out) < strlen(directory)) {
			return (ISC_R_NOSPACE);
		}
		isc_buffer_putstr(out, directory);
		if (strlen(directory) > 0U &&
		    directory[strlen(directory) - 1] != '/') {
			isc_buffer_putstr(out, "/");
		}
	}
	if (isc_buffer_availablelength(out) < 1) {
		return (ISC_R_NOSPACE);
	}
	isc_buffer_putstr(out, "K");
	result = dns_name_tofilenametext(name, false, out);
	if (result != ISC_R_SUCCESS) {
		return (result);
	}

	return (isc_buffer_printf(out, "+%03d+%05d%s", alg, id, suffix));
}

static isc_result_t
computeid(dst_key_t *key) {
	isc_buffer_t dnsbuf;
	unsigned char dns_array[DST_KEY_MAXSIZE];
	isc_region_t r;
	isc_result_t ret;

	isc_buffer_init(&dnsbuf, dns_array, sizeof(dns_array));
	ret = dst_key_todns(key, &dnsbuf);
	if (ret != ISC_R_SUCCESS) {
		return (ret);
	}

	isc_buffer_usedregion(&dnsbuf, &r);
	key->key_id = dst_region_computeid(&r);
	key->key_rid = dst_region_computerid(&r);
	return (ISC_R_SUCCESS);
}

static isc_result_t
frombuffer(const dns_name_t *name, unsigned int alg, unsigned int flags,
	   unsigned int protocol, dns_rdataclass_t rdclass,
	   isc_buffer_t *source, isc_mem_t *mctx, dst_key_t **keyp) {
	dst_key_t *key;
	isc_result_t ret;

	REQUIRE(dns_name_isabsolute(name));
	REQUIRE(source != NULL);
	REQUIRE(mctx != NULL);
	REQUIRE(keyp != NULL && *keyp == NULL);

	key = get_key_struct(name, alg, flags, protocol, 0, rdclass, 0, mctx);
	if (key == NULL) {
		return (ISC_R_NOMEMORY);
	}

	if (isc_buffer_remaininglength(source) > 0) {
		ret = algorithm_status(alg);
		if (ret != ISC_R_SUCCESS) {
			dst_key_free(&key);
			return (ret);
		}
		if (key->func->fromdns == NULL) {
			dst_key_free(&key);
			return (DST_R_UNSUPPORTEDALG);
		}

		ret = key->func->fromdns(key, source);
		if (ret != ISC_R_SUCCESS) {
			dst_key_free(&key);
			return (ret);
		}
	}

	*keyp = key;
	return (ISC_R_SUCCESS);
}

static isc_result_t
algorithm_status(unsigned int alg) {
	REQUIRE(dst_initialized);

	if (dst_algorithm_supported(alg)) {
		return (ISC_R_SUCCESS);
	}
	return (DST_R_UNSUPPORTEDALG);
}

static isc_result_t
addsuffix(char *filename, int len, const char *odirname, const char *ofilename,
	  const char *suffix) {
	int olen = strlen(ofilename);
	int n;

	if (olen > 1 && ofilename[olen - 1] == '.') {
		olen -= 1;
	} else if (olen > 8 && strcmp(ofilename + olen - 8, ".private") == 0) {
		olen -= 8;
	} else if (olen > 4 && strcmp(ofilename + olen - 4, ".key") == 0) {
		olen -= 4;
	}

	if (odirname == NULL) {
		n = snprintf(filename, len, "%.*s%s", olen, ofilename, suffix);
	} else {
		n = snprintf(filename, len, "%s/%.*s%s", odirname, olen,
			     ofilename, suffix);
	}
	if (n < 0) {
		return (ISC_R_FAILURE);
	}
	if (n >= len) {
		return (ISC_R_NOSPACE);
	}
	return (ISC_R_SUCCESS);
}

isc_buffer_t *
dst_key_tkeytoken(const dst_key_t *key) {
	REQUIRE(VALID_KEY(key));
	return (key->key_tkeytoken);
}

/*
 * A key is considered unused if it does not have any timing metadata set
 * other than "Created".
 *
 */
bool
dst_key_is_unused(dst_key_t *key) {
	isc_stdtime_t val;
	dst_key_state_t st;
	int state_type;
	bool state_type_set;

	REQUIRE(VALID_KEY(key));

	/*
	 * None of the key timing metadata, except Created, may be set.  Key
	 * state times may be set only if their respective state is HIDDEN.
	 */
	for (int i = 0; i < DST_MAX_TIMES + 1; i++) {
		state_type_set = false;

		switch (i) {
		case DST_TIME_CREATED:
			break;
		case DST_TIME_DNSKEY:
			state_type = DST_KEY_DNSKEY;
			state_type_set = true;
			break;
		case DST_TIME_ZRRSIG:
			state_type = DST_KEY_ZRRSIG;
			state_type_set = true;
			break;
		case DST_TIME_KRRSIG:
			state_type = DST_KEY_KRRSIG;
			state_type_set = true;
			break;
		case DST_TIME_DS:
			state_type = DST_KEY_DS;
			state_type_set = true;
			break;
		default:
			break;
		}

		/* Created is fine. */
		if (i == DST_TIME_CREATED) {
			continue;
		}
		/* No such timing metadata found, that is fine too. */
		if (dst_key_gettime(key, i, &val) == ISC_R_NOTFOUND) {
			continue;
		}
		/*
		 * Found timing metadata and it is not related to key states.
		 * This key is used.
		 */
		if (!state_type_set) {
			return (false);
		}
		/*
		 * If the state is not HIDDEN, the key is in use.
		 * If the state is not set, this is odd and we default to NA.
		 */
		if (dst_key_getstate(key, state_type, &st) != ISC_R_SUCCESS) {
			st = DST_KEY_STATE_NA;
		}
		if (st != DST_KEY_STATE_HIDDEN) {
			return (false);
		}
	}
	/* This key is unused. */
	return (true);
}

isc_result_t
dst_key_role(dst_key_t *key, bool *ksk, bool *zsk) {
	bool k = false, z = false;
	isc_result_t result, ret = ISC_R_SUCCESS;

	if (ksk != NULL) {
		result = dst_key_getbool(key, DST_BOOL_KSK, &k);
		if (result == ISC_R_SUCCESS) {
			*ksk = k;
		} else {
			*ksk = ((dst_key_flags(key) & DNS_KEYFLAG_KSK) != 0);
			ret = result;
		}
	}

	if (zsk != NULL) {
		result = dst_key_getbool(key, DST_BOOL_ZSK, &z);
		if (result == ISC_R_SUCCESS) {
			*zsk = z;
		} else {
			*zsk = ((dst_key_flags(key) & DNS_KEYFLAG_KSK) == 0);
			ret = result;
		}
	}
	return (ret);
}

/* Hints on key whether it can be published and/or used for signing. */

bool
dst_key_is_published(dst_key_t *key, isc_stdtime_t now,
		     isc_stdtime_t *publish) {
	dst_key_state_t state;
	isc_result_t result;
	isc_stdtime_t when;
	bool state_ok = true, time_ok = false;

	REQUIRE(VALID_KEY(key));

	result = dst_key_gettime(key, DST_TIME_PUBLISH, &when);
	if (result == ISC_R_SUCCESS) {
		*publish = when;
		time_ok = (when <= now);
	}

	/* Check key states:
	 * If the DNSKEY state is RUMOURED or OMNIPRESENT, it means it
	 * should be published.
	 */
	result = dst_key_getstate(key, DST_KEY_DNSKEY, &state);
	if (result == ISC_R_SUCCESS) {
		state_ok = ((state == DST_KEY_STATE_RUMOURED) ||
			    (state == DST_KEY_STATE_OMNIPRESENT));
		/*
		 * Key states trump timing metadata.
		 * Ignore inactive time.
		 */
		time_ok = true;
	}

	return (state_ok && time_ok);
}

bool
dst_key_is_active(dst_key_t *key, isc_stdtime_t now) {
	dst_key_state_t state;
	isc_result_t result;
	isc_stdtime_t when = 0;
	bool ksk = false, zsk = false, inactive = false;
	bool ds_ok = true, zrrsig_ok = true, time_ok = false;

	REQUIRE(VALID_KEY(key));

	result = dst_key_gettime(key, DST_TIME_INACTIVE, &when);
	if (result == ISC_R_SUCCESS) {
		inactive = (when <= now);
	}

	result = dst_key_gettime(key, DST_TIME_ACTIVATE, &when);
	if (result == ISC_R_SUCCESS) {
		time_ok = (when <= now);
	}

	(void)dst_key_role(key, &ksk, &zsk);

	/* Check key states:
	 * KSK: If the DS is RUMOURED or OMNIPRESENT the key is considered
	 * active.
	 */
	if (ksk) {
		result = dst_key_getstate(key, DST_KEY_DS, &state);
		if (result == ISC_R_SUCCESS) {
			ds_ok = ((state == DST_KEY_STATE_RUMOURED) ||
				 (state == DST_KEY_STATE_OMNIPRESENT));
			/*
			 * Key states trump timing metadata.
			 * Ignore inactive time.
			 */
			time_ok = true;
			inactive = false;
		}
	}
	/*
	 * ZSK: If the ZRRSIG state is RUMOURED or OMNIPRESENT, it means the
	 * key is active.
	 */
	if (zsk) {
		result = dst_key_getstate(key, DST_KEY_ZRRSIG, &state);
		if (result == ISC_R_SUCCESS) {
			zrrsig_ok = ((state == DST_KEY_STATE_RUMOURED) ||
				     (state == DST_KEY_STATE_OMNIPRESENT));
			/*
			 * Key states trump timing metadata.
			 * Ignore inactive time.
			 */
			time_ok = true;
			inactive = false;
		}
	}
	return (ds_ok && zrrsig_ok && time_ok && !inactive);
}

bool
dst_key_is_signing(dst_key_t *key, int role, isc_stdtime_t now,
		   isc_stdtime_t *active) {
	dst_key_state_t state;
	isc_result_t result;
	isc_stdtime_t when = 0;
	bool ksk = false, zsk = false, inactive = false;
	bool krrsig_ok = true, zrrsig_ok = true, time_ok = false;

	REQUIRE(VALID_KEY(key));

	result = dst_key_gettime(key, DST_TIME_INACTIVE, &when);
	if (result == ISC_R_SUCCESS) {
		inactive = (when <= now);
	}

	result = dst_key_gettime(key, DST_TIME_ACTIVATE, &when);
	if (result == ISC_R_SUCCESS) {
		*active = when;
		time_ok = (when <= now);
	}

	(void)dst_key_role(key, &ksk, &zsk);

	/* Check key states:
	 * If the RRSIG state is RUMOURED or OMNIPRESENT, it means the key
	 * is active.
	 */
	if (ksk && role == DST_BOOL_KSK) {
		result = dst_key_getstate(key, DST_KEY_KRRSIG, &state);
		if (result == ISC_R_SUCCESS) {
			krrsig_ok = ((state == DST_KEY_STATE_RUMOURED) ||
				     (state == DST_KEY_STATE_OMNIPRESENT));
			/*
			 * Key states trump timing metadata.
			 * Ignore inactive time.
			 */
			time_ok = true;
			inactive = false;
		}
	} else if (zsk && role == DST_BOOL_ZSK) {
		result = dst_key_getstate(key, DST_KEY_ZRRSIG, &state);
		if (result == ISC_R_SUCCESS) {
			zrrsig_ok = ((state == DST_KEY_STATE_RUMOURED) ||
				     (state == DST_KEY_STATE_OMNIPRESENT));
			/*
			 * Key states trump timing metadata.
			 * Ignore inactive time.
			 */
			time_ok = true;
			inactive = false;
		}
	}
	return (krrsig_ok && zrrsig_ok && time_ok && !inactive);
}

bool
dst_key_is_revoked(dst_key_t *key, isc_stdtime_t now, isc_stdtime_t *revoke) {
	isc_result_t result;
	isc_stdtime_t when = 0;
	bool time_ok = false;

	REQUIRE(VALID_KEY(key));

	result = dst_key_gettime(key, DST_TIME_REVOKE, &when);
	if (result == ISC_R_SUCCESS) {
		*revoke = when;
		time_ok = (when <= now);
	}

	return (time_ok);
}

bool
dst_key_is_removed(dst_key_t *key, isc_stdtime_t now, isc_stdtime_t *remove) {
	dst_key_state_t state;
	isc_result_t result;
	isc_stdtime_t when = 0;
	bool state_ok = true, time_ok = false;

	REQUIRE(VALID_KEY(key));

	if (dst_key_is_unused(key)) {
		/* This key was never used. */
		return (false);
	}

	result = dst_key_gettime(key, DST_TIME_DELETE, &when);
	if (result == ISC_R_SUCCESS) {
		*remove = when;
		time_ok = (when <= now);
	}

	/* Check key states:
	 * If the DNSKEY state is UNRETENTIVE or HIDDEN, it means the key
	 * should not be published.
	 */
	result = dst_key_getstate(key, DST_KEY_DNSKEY, &state);
	if (result == ISC_R_SUCCESS) {
		state_ok = ((state == DST_KEY_STATE_UNRETENTIVE) ||
			    (state == DST_KEY_STATE_HIDDEN));
		/*
		 * Key states trump timing metadata.
		 * Ignore delete time.
		 */
		time_ok = true;
	}

	return (state_ok && time_ok);
}

dst_key_state_t
dst_key_goal(dst_key_t *key) {
	dst_key_state_t state;
	isc_result_t result;

	REQUIRE(VALID_KEY(key));

	result = dst_key_getstate(key, DST_KEY_GOAL, &state);
	if (result == ISC_R_SUCCESS) {
		return (state);
	}
	return (DST_KEY_STATE_HIDDEN);
}

bool
dst_key_haskasp(dst_key_t *key) {
	REQUIRE(VALID_KEY(key));

	return (key->kasp);
}

void
dst_key_copy_metadata(dst_key_t *to, dst_key_t *from) {
	dst_key_state_t state;
	isc_stdtime_t when;
	uint32_t num;
	bool yesno;
	isc_result_t result;

	REQUIRE(VALID_KEY(to));
	REQUIRE(VALID_KEY(from));

	for (int i = 0; i < DST_MAX_TIMES + 1; i++) {
		result = dst_key_gettime(from, i, &when);
		if (result == ISC_R_SUCCESS) {
			dst_key_settime(to, i, when);
		} else {
			dst_key_unsettime(to, i);
		}
	}

	for (int i = 0; i < DST_MAX_NUMERIC + 1; i++) {
		result = dst_key_getnum(from, i, &num);
		if (result == ISC_R_SUCCESS) {
			dst_key_setnum(to, i, num);
		} else {
			dst_key_unsetnum(to, i);
		}
	}

	for (int i = 0; i < DST_MAX_BOOLEAN + 1; i++) {
		result = dst_key_getbool(from, i, &yesno);
		if (result == ISC_R_SUCCESS) {
			dst_key_setbool(to, i, yesno);
		} else {
			dst_key_unsetbool(to, i);
		}
	}

	for (int i = 0; i < DST_MAX_KEYSTATES + 1; i++) {
		result = dst_key_getstate(from, i, &state);
		if (result == ISC_R_SUCCESS) {
			dst_key_setstate(to, i, state);
		} else {
			dst_key_unsetstate(to, i);
		}
	}

	dst_key_setmodified(to, dst_key_ismodified(from));
}

const char *
dst_hmac_algorithm_totext(dst_algorithm_t alg) {
	switch (alg) {
	case DST_ALG_HMACMD5:
		return ("hmac-md5");
	case DST_ALG_HMACSHA1:
		return ("hmac-sha1");
	case DST_ALG_HMACSHA224:
		return ("hmac-sha224");
	case DST_ALG_HMACSHA256:
		return ("hmac-sha256");
	case DST_ALG_HMACSHA384:
		return ("hmac-sha384");
	case DST_ALG_HMACSHA512:
		return ("hmac-sha512");
	default:
		return ("unknown");
	}
}