/*
 * Portions Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * 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.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * Portions 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.
 */

/*
 * Principal Author: Brian Wellington
 * $Id: dst_api.c,v 1.5 2020/02/18 18:11:27 florian Exp $
 */

/*! \file */
#include <stdlib.h>

#include <isc/buffer.h>
#include <isc/lex.h>
#include <isc/refcount.h>
#include <isc/safe.h>
#include <string.h>
#include <isc/util.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/result.h>

#include "dst_internal.h"

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

static dst_func_t *dst_t_func[DST_MAX_ALGS];
static isc_boolean_t dst_initialized = ISC_FALSE;

/*
 * Static functions.
 */
static dst_key_t *	get_key_struct(dns_name_t *name,
				       unsigned int alg,
				       unsigned int flags,
				       unsigned int protocol,
				       unsigned int bits,
				       dns_rdataclass_t rdclass,
				       dns_ttl_t ttl);
static isc_result_t	computeid(dst_key_t *key);
static isc_result_t	frombuffer(dns_name_t *name,
				   unsigned int alg,
				   unsigned int flags,
				   unsigned int protocol,
				   dns_rdataclass_t rdclass,
				   isc_buffer_t *source,
				   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(void) {
	isc_result_t result;

	REQUIRE(dst_initialized == ISC_FALSE);

	dst_result_register();

	memset(dst_t_func, 0, sizeof(dst_t_func));
	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());
	dst_initialized = ISC_TRUE;
	return (ISC_R_SUCCESS);

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

void
dst_lib_destroy(void) {
	int i;
	RUNTIME_CHECK(dst_initialized == ISC_TRUE);
	dst_initialized = ISC_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();
}

isc_boolean_t
dst_algorithm_supported(unsigned int alg) {
	REQUIRE(dst_initialized == ISC_TRUE);

	if (alg >= DST_MAX_ALGS || dst_t_func[alg] == NULL)
		return (ISC_FALSE);
	return (ISC_TRUE);
}

isc_result_t
dst_context_create(dst_key_t *key, dst_context_t **dctxp) {
	return (dst_context_create4(key, DNS_LOGCATEGORY_GENERAL,
				    ISC_TRUE, 0, dctxp));
}

isc_result_t
dst_context_create2(dst_key_t *key,
		    isc_logcategory_t *category, dst_context_t **dctxp)
{
	return (dst_context_create4(key, category, ISC_TRUE, 0, dctxp));
}

isc_result_t
dst_context_create3(dst_key_t *key,
		    isc_logcategory_t *category, isc_boolean_t useforsigning,
		    dst_context_t **dctxp)
{
	return (dst_context_create4(key, category,
				    useforsigning, 0, dctxp));
}

isc_result_t
dst_context_create4(dst_key_t *key,
		    isc_logcategory_t *category, isc_boolean_t useforsigning,
		    int maxbits, dst_context_t **dctxp)
{
	dst_context_t *dctx;
	isc_result_t result;

	REQUIRE(dst_initialized == ISC_TRUE);
	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 = malloc(sizeof(dst_context_t));
	if (dctx == NULL)
		return (ISC_R_NOMEMORY);
	memset(dctx, 0, sizeof(*dctx));
	dst_key_attach(key, &dctx->key);
	dctx->category = category;
	if (useforsigning)
		dctx->use = DO_SIGN;
	else
		dctx->use = DO_VERIFY;
	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);
		free(dctx);
		return (result);
	}
	*dctxp = dctx;
	return (ISC_R_SUCCESS);
}

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

	REQUIRE(dctxp != NULL);

	dctx = *dctxp;
	INSIST(dctx->key->func->destroyctx != NULL);
	dctx->key->func->destroyctx(dctx);
	if (dctx->key != NULL)
		dst_key_free(&dctx->key);
	free(dctx);
	*dctxp = NULL;
}

isc_result_t
dst_context_adddata(dst_context_t *dctx, const isc_region_t *data) {
	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(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) == ISC_FALSE)
		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(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(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_fromnamedfile(const char *filename, const char *dirname,
		      int type, dst_key_t **keyp)
{
	isc_result_t result;
	dst_key_t *pubkey = NULL, *key = NULL;
	char *newfilename = NULL;
	int newfilenamelen = 0;
	isc_lex_t *lex = NULL;

	REQUIRE(dst_initialized == ISC_TRUE);
	REQUIRE(filename != NULL);
	REQUIRE((type & (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC)) != 0);
	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 = malloc(newfilenamelen);
	if (newfilename == NULL)
		return (ISC_R_NOMEMORY);
	result = addsuffix(newfilename, newfilenamelen,
			   dirname, filename, ".key");
	INSIST(result == ISC_R_SUCCESS);

	result = dst_key_read_public(newfilename, type, &pubkey);
	free(newfilename);
	newfilename = NULL;
	RETERR(result);

	if ((type & (DST_TYPE_PRIVATE | DST_TYPE_PUBLIC)) == DST_TYPE_PUBLIC ||
	    (pubkey->key_flags & DNS_KEYFLAG_TYPEMASK) == DNS_KEYTYPE_NOKEY) {
		result = computeid(pubkey);
		if (result != ISC_R_SUCCESS) {
			dst_key_free(&pubkey);
			return (result);
		}

		*keyp = pubkey;
		return (ISC_R_SUCCESS);
	}

	result = algorithm_status(pubkey->key_alg);
	if (result != ISC_R_SUCCESS) {
		dst_key_free(&pubkey);
		return (result);
	}

	key = get_key_struct(pubkey->key_name, pubkey->key_alg,
			     pubkey->key_flags, pubkey->key_proto, 0,
			     pubkey->key_class, pubkey->key_ttl);
	if (key == NULL) {
		dst_key_free(&pubkey);
		return (ISC_R_NOMEMORY);
	}

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

	newfilenamelen = strlen(filename) + 9;
	if (dirname != NULL)
		newfilenamelen += strlen(dirname) + 1;
	newfilename = malloc(newfilenamelen);
	if (newfilename == NULL)
		RETERR(ISC_R_NOMEMORY);
	result = addsuffix(newfilename, newfilenamelen,
			   dirname, filename, ".private");
	INSIST(result == ISC_R_SUCCESS);

	RETERR(isc_lex_create(1500, &lex));
	RETERR(isc_lex_openfile(lex, newfilename));
	free(newfilename);
	newfilename = NULL;

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

	RETERR(computeid(key));

	if (pubkey->key_id != key->key_id)
		RETERR(DST_R_INVALIDPRIVATEKEY);
	dst_key_free(&pubkey);

	*keyp = key;
	return (ISC_R_SUCCESS);

 out:
	if (pubkey != NULL)
		dst_key_free(&pubkey);
	if (newfilename != NULL)
		free(newfilename);
	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 == ISC_TRUE);
	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) {
		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(dns_name_t *name, dns_rdataclass_t rdclass,
		isc_buffer_t *source, 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, alg);
	rid = dst_region_computerid(&r, alg);

	if (flags & DNS_KEYFLAG_EXTENDED) {
		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,
			    &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(dns_name_t *name, unsigned int alg,
		   unsigned int flags, unsigned int protocol,
		   dns_rdataclass_t rdclass,
		   isc_buffer_t *source, dst_key_t **keyp)
{
	dst_key_t *key = NULL;
	isc_result_t result;

	REQUIRE(dst_initialized);

	result = frombuffer(name, alg, flags, protocol, rdclass, source,
			    &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);
}

void
dst_key_attach(dst_key_t *source, dst_key_t **target) {

	REQUIRE(dst_initialized == ISC_TRUE);
	REQUIRE(target != NULL && *target == NULL);

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

void
dst_key_free(dst_key_t **keyp) {
	dst_key_t *key;
	unsigned int refs;

	REQUIRE(dst_initialized == ISC_TRUE);
	REQUIRE(keyp != NULL);

	key = *keyp;

	isc_refcount_decrement(&key->refs, &refs);
	if (refs != 0)
		return;

	isc_refcount_destroy(&key->refs);
	if (key->keydata.generic != NULL) {
		INSIST(key->func->destroy != NULL);
		key->func->destroy(key);
	}
	if (key->engine != NULL)
		free(key->engine);
	if (key->label != NULL)
		free(key->label);
	dns_name_free(key->key_name);
	free(key->key_name);
	if (key->key_tkeytoken) {
		isc_buffer_free(&key->key_tkeytoken);
	}
	isc_safe_memwipe(key, sizeof(*key));
	free(key);
	*keyp = NULL;
}

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

	/* XXXVIX this switch statement is too sparse to gen a jump table. */
	switch (key->key_alg) {
	case DST_ALG_HMACSHA1:
		*n = ISC_SHA1_DIGESTLENGTH;
		break;
	case DST_ALG_HMACSHA224:
		*n = ISC_SHA224_DIGESTLENGTH;
		break;
	case DST_ALG_HMACSHA256:
		*n = ISC_SHA256_DIGESTLENGTH;
		break;
	case DST_ALG_HMACSHA384:
		*n = ISC_SHA384_DIGESTLENGTH;
		break;
	case DST_ALG_HMACSHA512:
		*n = ISC_SHA512_DIGESTLENGTH;
		break;
	default:
		return (DST_R_UNSUPPORTEDALG);
	}
	return (ISC_R_SUCCESS);
}

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

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

	key = (dst_key_t *) malloc(sizeof(dst_key_t));
	if (key == NULL)
		return (NULL);

	memset(key, 0, sizeof(dst_key_t));

	key->key_name = malloc(sizeof(dns_name_t));
	if (key->key_name == NULL) {
		free(key);
		return (NULL);
	}

	dns_name_init(key->key_name, NULL);
	result = dns_name_dup(name, key->key_name);
	if (result != ISC_R_SUCCESS) {
		free(key->key_name);
		free(key);
		return (NULL);
	}

	result = isc_refcount_init(&key->refs, 1);
	if (result != ISC_R_SUCCESS) {
		dns_name_free(key->key_name);
		free(key->key_name);
		free(key);
		return (NULL);
	}
	key->key_alg = alg;
	key->key_flags = flags;
	key->key_proto = protocol;
	key->keydata.generic = NULL;
	key->key_size = bits;
	key->key_class = rdclass;
	key->key_ttl = ttl;
	key->func = dst_t_func[alg];
	key->fmt_major = 0;
	key->fmt_minor = 0;
	for (i = 0; i < (DST_MAX_TIMES + 1); i++) {
		key->times[i] = 0;
		key->timeset[i] = ISC_FALSE;
	}
	key->inactive = ISC_FALSE;
	return (key);
}

/*%
 * Reads a public key from disk
 */
isc_result_t
dst_key_read_public(const char *filename, int type,
		    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(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;

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

#define BADTOKEN() { \
	ret = ISC_R_UNEXPECTEDTOKEN; \
	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,
				 ISC_FALSE, &b, NULL);
	if (ret != ISC_R_SUCCESS)
		goto cleanup;

	ret = dst_key_fromdns(dns_fixedname_name(&name), rdclass, &b, keyp);
	if (ret != ISC_R_SUCCESS)
		goto cleanup;
 cleanup:
	if (lex != NULL)
		isc_lex_destroy(&lex);
	return (ret);
}

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_alg);
	key->key_rid = dst_region_computerid(&r, key->key_alg);
	return (ISC_R_SUCCESS);
}

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

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

	key = get_key_struct(name, alg, flags, protocol, 0, rdclass, 0);
	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 == ISC_TRUE);

	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);
}