/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * SPDX-License-Identifier: MPL-2.0

 *

 * 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.

 */

#include <ctype.h>

#include <inttypes.h>

#include <stdbool.h>

#include <stdlib.h>

#include <isc/ascii.h>

#include <isc/buffer.h>

#include <isc/parseint.h>

#include <isc/region.h>

#include <isc/result.h>

#include <isc/stdio.h>

#include <isc/string.h>

#include <isc/types.h>

#include <isc/util.h>

#include <dns/cert.h>

#include <dns/ds.h>

#include <dns/dsdigest.h>

#include <dns/dsync.h>

#include <dns/keyflags.h>

#include <dns/keyvalues.h>

#include <dns/rcode.h>

#include <dns/rdataclass.h>

#include <dns/secalg.h>

#include <dns/secproto.h>

#include <dst/dst.h>

#define NUMBERSIZE sizeof("037777777777") /* 2^32-1 octal + NUL */

#define TOTEXTONLY 0x01

/* clang-format off */

#define SENTINEL { 0, NULL, 0 }

/* clang-format on */

#define RCODENAMES                                     \

  /* standard rcodes */                          \

  { dns_rcode_noerror, "NOERROR", 0 },           \

    { dns_rcode_formerr, "FORMERR", 0 },   \

    { dns_rcode_servfail, "SERVFAIL", 0 }, \

    { dns_rcode_nxdomain, "NXDOMAIN", 0 }, \

    { dns_rcode_notimp, "NOTIMP", 0 },     \

    { dns_rcode_refused, "REFUSED", 0 },   \

    { dns_rcode_yxdomain, "YXDOMAIN", 0 }, \

    { dns_rcode_yxrrset, "YXRRSET", 0 },   \

    { dns_rcode_nxrrset, "NXRRSET", 0 },   \

    { dns_rcode_notauth, "NOTAUTH", 0 },   \

    { dns_rcode_notzone, "NOTZONE", 0 },   \

    { 11, "RESERVED11", TOTEXTONLY },      \

    { 12, "RESERVED12", TOTEXTONLY },      \

    { 13, "RESERVED13", TOTEXTONLY },      \

    { 14, "RESERVED14", TOTEXTONLY },      \

    { 15, "RESERVED15", TOTEXTONLY },

#define ERCODENAMES                          \

  /* extended rcodes */                \

  { dns_rcode_badvers, "BADVERS", 0 }, \

    { dns_rcode_badcookie, "BADCOOKIE", 0 }, SENTINEL

#define TSIGRCODENAMES                                   \

  /* extended rcodes */                            \

  { dns_tsigerror_badsig, "BADSIG", 0 },           \

    { dns_tsigerror_badkey, "BADKEY", 0 },   \

    { dns_tsigerror_badtime, "BADTIME", 0 }, \

    { dns_tsigerror_badmode, "BADMODE", 0 }, \

    { dns_tsigerror_badname, "BADNAME", 0 }, \

    { dns_tsigerror_badalg, "BADALG", 0 },   \

    { dns_tsigerror_badtrunc, "BADTRUNC", 0 }, SENTINEL

/* RFC4398 section 2.1 */

#define CERTNAMES                                                           \

  { 1, "PKIX", 0 }, { 2, "SPKI", 0 }, { 3, "PGP", 0 },                \

    { 4, "IPKIX", 0 }, { 5, "ISPKI", 0 }, { 6, "IPGP", 0 },     \

    { 7, "ACPKIX", 0 }, { 8, "IACPKIX", 0 }, { 253, "URI", 0 }, \

    { 254, "OID", 0 }, SENTINEL

/* RFC2535 section 7, RFC3110 */

#define SECALGNAMES                                             \

  { DNS_KEYALG_RSAMD5, "RSAMD5", 0 },                     \

    { DNS_KEYALG_DH_DEPRECATED, "DH", 0 },          \

    { DNS_KEYALG_DSA, "DSA", 0 },                   \

    { DNS_KEYALG_RSASHA1, "RSASHA1", 0 },           \

    { DNS_KEYALG_NSEC3DSA, "NSEC3DSA", 0 },         \

    { DNS_KEYALG_NSEC3RSASHA1, "NSEC3RSASHA1", 0 }, \

    { DNS_KEYALG_RSASHA256, "RSASHA256", 0 },       \

    { DNS_KEYALG_RSASHA512, "RSASHA512", 0 },       \

    { DNS_KEYALG_ECCGOST, "ECCGOST", 0 },           \

    { DNS_KEYALG_ECDSA256, "ECDSAP256SHA256", 0 },  \

    { DNS_KEYALG_ECDSA256, "ECDSA256", 0 },         \

    { DNS_KEYALG_ECDSA384, "ECDSAP384SHA384", 0 },  \

    { DNS_KEYALG_ECDSA384, "ECDSA384", 0 },         \

    { DNS_KEYALG_ED25519, "ED25519", 0 },           \

    { DNS_KEYALG_ED448, "ED448", 0 },               \

    { DNS_KEYALG_INDIRECT, "INDIRECT", 0 },         \

    { DNS_KEYALG_PRIVATEDNS, "PRIVATEDNS", 0 },     \

    { DNS_KEYALG_PRIVATEOID, "PRIVATEOID", 0 }, SENTINEL

/*

 * PRIVATEDNS subtypes we support.

 */

#define PRIVATEDNSS /* currently empty */

/*

 * PRIVATEOID subtypes we support.

 */

#define PRIVATEOIDS                                         \

  { DST_ALG_RSASHA256PRIVATEOID, "RSASHA256OID", 0 }, \

    { DST_ALG_RSASHA512PRIVATEOID, "RSASHA512OID", 0 },

/* RFC2535 section 7.1 */

#define SECPROTONAMES                                                     \

  { 0, "NONE", 0 }, { 1, "TLS", 0 }, { 2, "EMAIL", 0 },             \

    { 3, "DNSSEC", 0 }, { 4, "IPSEC", 0 }, { 255, "ALL", 0 }, \

    SENTINEL

#define HASHALGNAMES { 1, "SHA-1", 0 }, SENTINEL

/* RFC3658, RFC4509, RFC5933, RFC6605, RFC9558, RFC9563 */

#if defined(DNS_DSDIGEST_SHA256PRIVATE) &&     \

  defined(DNS_DSDIGEST_SHA384PRIVATE) && \

  defined(DNS_DSDIGEST_SM3PRIVATE)

#define DSDIGESTPRIVATENAMES                                          \

  { DNS_DSDIGEST_SHA256PRIVATE, "SHA-256-PRIVATE", 0 },         \

    { DNS_DSDIGEST_SHA256PRIVATE, "SHA256PRIVATE", 0 },   \

    { DNS_DSDIGEST_SHA384PRIVATE, "SHA-384-PRIVATE", 0 }, \

    { DNS_DSDIGEST_SHA384PRIVATE, "SHA384PRIVATE", 0 },   \

    { DNS_DSDIGEST_SM3PRIVATE, "SM3-PRIVATE", 0 },        \

    { DNS_DSDIGEST_SM3PRIVATE, "SM3PRIVATE", 0 },

#else

#define DSDIGESTPRIVATENAMES

#endif

#define DSDIGESTNAMES                                                        \

  { DNS_DSDIGEST_SHA1, "SHA-1", 0 }, { DNS_DSDIGEST_SHA1, "SHA1", 0 }, \

    { DNS_DSDIGEST_SHA256, "SHA-256", 0 },                       \

    { DNS_DSDIGEST_SHA256, "SHA256", 0 },                        \

    { DNS_DSDIGEST_GOST, "GOST", 0 },                            \

    { DNS_DSDIGEST_SM3, "SM3", 0 },                              \

    { DNS_DSDIGEST_SHA384, "SHA-384", 0 },                       \

    { DNS_DSDIGEST_SHA384, "SHA384", 0 },                        \

    { DNS_DSDIGEST_GOST2012, "GOST-2012", 0 },                   \

    { DNS_DSDIGEST_GOST2012, "GOST2012", 0 },                    \

    DSDIGESTPRIVATENAMES SENTINEL

#define DSYNCSCHEMES { DNS_DSYNCSCHEME_NOTIFY, "NOTIFY", 0 }, SENTINEL

struct tbl {

  unsigned int value;

  const char *name;

  int flags;

};

static struct tbl rcodes[] = { RCODENAMES ERCODENAMES };

static struct tbl tsigrcodes[] = { RCODENAMES TSIGRCODENAMES };

static struct tbl certs[] = { CERTNAMES };

static struct tbl secalgs[] = { SECALGNAMES };

static struct tbl secprotos[] = { SECPROTONAMES };

static struct tbl hashalgs[] = { HASHALGNAMES };

static struct tbl dsdigests[] = { DSDIGESTNAMES };

static struct tbl dsyncschemes[] = { DSYNCSCHEMES };

static struct tbl privatednss[] = { PRIVATEDNSS SENTINEL };

static struct tbl privateoids[] = { PRIVATEOIDS SENTINEL };

static struct tbl dstalgorithms[] = { PRIVATEDNSS PRIVATEOIDS SECALGNAMES };

static struct keyflag {

  const char *name;

  unsigned int value;

  unsigned int mask;

} keyflags[] = { { "NOCONF", 0x4000, 0xC000 },

     { "NOAUTH", 0x8000, 0xC000 },

     { "NOKEY", 0xC000, 0xC000 },

     { "FLAG2", 0x2000, 0x2000 },

     { "EXTEND", 0x1000, 0x1000 },

     { "FLAG4", 0x0800, 0x0800 },

     { "FLAG5", 0x0400, 0x0400 },

     { "USER", 0x0000, 0x0300 },

     { "ZONE", 0x0100, 0x0300 },

     { "HOST", 0x0200, 0x0300 },

     { "NTYP3", 0x0300, 0x0300 },

     { "FLAG8", 0x0080, 0x0080 },

     { "FLAG9", 0x0040, 0x0040 },

     { "FLAG10", 0x0020, 0x0020 },

     { "FLAG11", 0x0010, 0x0010 },

     { "SIG0", 0x0000, 0x000F },

     { "SIG1", 0x0001, 0x000F },

     { "SIG2", 0x0002, 0x000F },

     { "SIG3", 0x0003, 0x000F },

     { "SIG4", 0x0004, 0x000F },

     { "SIG5", 0x0005, 0x000F },

     { "SIG6", 0x0006, 0x000F },

     { "SIG7", 0x0007, 0x000F },

     { "SIG8", 0x0008, 0x000F },

     { "SIG9", 0x0009, 0x000F },

     { "SIG10", 0x000A, 0x000F },

     { "SIG11", 0x000B, 0x000F },

     { "SIG12", 0x000C, 0x000F },

     { "SIG13", 0x000D, 0x000F },

     { "SIG14", 0x000E, 0x000F },

     { "SIG15", 0x000F, 0x000F },

     { "KSK", DNS_KEYFLAG_KSK, DNS_KEYFLAG_KSK },

     { NULL, 0, 0 } };

static isc_result_t

str_totext(const char *source, isc_buffer_t *target) {

  unsigned int l;

  isc_region_t region;

  isc_buffer_availableregion(target, &region);

  l = strlen(source);

  if (l > region.length) {

    return ISC_R_NOSPACE;

  }

  memmove(region.base, source, l);

  isc_buffer_add(target, l);

  return ISC_R_SUCCESS;

}

static isc_result_t

maybe_numeric(unsigned int *valuep, isc_textregion_t *source, unsigned int max,

        bool hex_allowed) {

  isc_result_t result;

  uint32_t n;

  char buffer[NUMBERSIZE];

  int v;

  if (!isdigit((unsigned char)source->base[0]) ||

      source->length > NUMBERSIZE - 1)

  {

    return ISC_R_BADNUMBER;

  }

  /*

   * We have a potential number.  Try to parse it with

   * isc_parse_uint32().  isc_parse_uint32() requires

   * null termination, so we must make a copy.

   */

  v = snprintf(buffer, sizeof(buffer), "%.*s", (int)source->length,

         source->base);

  if (v < 0 || (unsigned int)v != source->length) {

    return ISC_R_BADNUMBER;

  }

  INSIST(buffer[source->length] == '\0');

  result = isc_parse_uint32(&n, buffer, 10);

  if (result == ISC_R_BADNUMBER && hex_allowed) {

    result = isc_parse_uint32(&n, buffer, 16);

  }

  if (result != ISC_R_SUCCESS) {

    return result;

  }

  if (n > max) {

    return ISC_R_RANGE;

  }

  *valuep = n;

  return ISC_R_SUCCESS;

}

static isc_result_t

dns_mnemonic_fromtext(unsigned int *valuep, isc_textregion_t *source,

          struct tbl *table, unsigned int max) {

  isc_result_t result;

  int i;

  result = maybe_numeric(valuep, source, max, false);

  if (result != ISC_R_BADNUMBER) {

    return result;

  }

  for (i = 0; table[i].name != NULL; i++) {

    unsigned int n;

    n = strlen(table[i].name);

    if (n == source->length && (table[i].flags & TOTEXTONLY) == 0 &&

        strncasecmp(source->base, table[i].name, n) == 0)

    {

      *valuep = table[i].value;

      return ISC_R_SUCCESS;

    }

  }

  return DNS_R_UNKNOWN;

}

static isc_result_t

dns_mnemonic_totext(unsigned int value, isc_buffer_t *target,

        struct tbl *table) {

  int i = 0;

  char buf[sizeof("4294967296")];

  while (table[i].name != NULL) {

    if (table[i].value == value) {

      return str_totext(table[i].name, target);

    }

    i++;

  }

  snprintf(buf, sizeof(buf), "%u", value);

  return str_totext(buf, target);

}

isc_result_t

dns_rcode_fromtext(dns_rcode_t *rcodep, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, rcodes, 0xffff));

  *rcodep = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_rcode_totext(dns_rcode_t rcode, isc_buffer_t *target) {

  return dns_mnemonic_totext(rcode, target, rcodes);

}

isc_result_t

dns_tsigrcode_fromtext(dns_rcode_t *rcodep, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, tsigrcodes, 0xffff));

  *rcodep = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_tsigrcode_totext(dns_rcode_t rcode, isc_buffer_t *target) {

  return dns_mnemonic_totext(rcode, target, tsigrcodes);

}

isc_result_t

dns_cert_fromtext(dns_cert_t *certp, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, certs, 0xffff));

  *certp = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_cert_totext(dns_cert_t cert, isc_buffer_t *target) {

  return dns_mnemonic_totext(cert, target, certs);

}

isc_result_t

dns_secalg_fromtext(dns_secalg_t *secalgp, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, secalgs, 0xff));

  *secalgp = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_secalg_totext(dns_secalg_t secalg, isc_buffer_t *target) {

  return dns_mnemonic_totext(secalg, target, secalgs);

}

void

dns_secalg_format(dns_secalg_t alg, char *cp, unsigned int size) {

  isc_buffer_t b;

  isc_region_t r;

  isc_result_t result;

  REQUIRE(cp != NULL && size > 0);

  isc_buffer_init(&b, cp, size - 1);

  result = dns_secalg_totext(alg, &b);

  isc_buffer_usedregion(&b, &r);

  r.base[r.length] = 0;

  if (result != ISC_R_SUCCESS) {

    r.base[0] = 0;

  }

}

isc_result_t

dst_privatedns_fromtext(dst_algorithm_t *dstalgp, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, privatednss, 0));

  *dstalgp = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_privatedns_totext(dst_algorithm_t alg, isc_buffer_t *target) {

  return dns_mnemonic_totext(alg, target, privatednss);

}

void

dns_privatedns_format(dst_algorithm_t alg, char *cp, unsigned int size) {

  isc_buffer_t b;

  isc_region_t r;

  isc_result_t result;

  REQUIRE(cp != NULL && size > 0);

  isc_buffer_init(&b, cp, size - 1);

  result = dns_privatedns_totext(alg, &b);

  isc_buffer_usedregion(&b, &r);

  r.base[r.length] = 0;

  if (result != ISC_R_SUCCESS) {

    r.base[0] = 0;

  }

}

isc_result_t

dst_privateoid_fromtext(dst_algorithm_t *dstalgp, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, privateoids, 0));

  *dstalgp = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_privateoid_totext(dst_algorithm_t alg, isc_buffer_t *target) {

  return dns_mnemonic_totext(alg, target, privateoids);

}

void

dns_privateoid_format(dst_algorithm_t alg, char *cp, unsigned int size) {

  isc_buffer_t b;

  isc_region_t r;

  isc_result_t result;

  REQUIRE(cp != NULL && size > 0);

  isc_buffer_init(&b, cp, size - 1);

  result = dns_privateoid_totext(alg, &b);

  isc_buffer_usedregion(&b, &r);

  r.base[r.length] = 0;

  if (result != ISC_R_SUCCESS) {

    r.base[0] = 0;

  }

}

isc_result_t

dns_secproto_fromtext(dns_secproto_t *secprotop, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, secprotos, 0xff));

  *secprotop = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_secproto_totext(dns_secproto_t secproto, isc_buffer_t *target) {

  return dns_mnemonic_totext(secproto, target, secprotos);

}

isc_result_t

dns_hashalg_fromtext(unsigned char *hashalg, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, hashalgs, 0xff));

  *hashalg = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_keyflags_fromtext(dns_keyflags_t *flagsp, isc_textregion_t *source) {

  isc_result_t result;

  char *text, *end;

  unsigned int value = 0;

#ifdef notyet

  unsigned int mask = 0;

#endif /* ifdef notyet */

  result = maybe_numeric(&value, source, 0xffff, true);

  if (result == ISC_R_SUCCESS) {

    *flagsp = value;

    return ISC_R_SUCCESS;

  }

  if (result != ISC_R_BADNUMBER) {

    return result;

  }

  text = source->base;

  end = source->base + source->length;

  while (text < end) {

    struct keyflag *p;

    unsigned int len;

    char *delim = memchr(text, '|', end - text);

    if (delim != NULL) {

      len = (unsigned int)(delim - text);

    } else {

      len = (unsigned int)(end - text);

    }

    for (p = keyflags; p->name != NULL; p++) {

      if (strncasecmp(p->name, text, len) == 0) {

        break;

      }

    }

    if (p->name == NULL) {

      return DNS_R_UNKNOWNFLAG;

    }

    value |= p->value;

#ifdef notyet

    if ((mask & p->mask) != 0) {

      warn("overlapping key flags");

    }

    mask |= p->mask;

#endif /* ifdef notyet */

    text += len;

    if (delim != NULL) {

      text++; /* Skip "|" */

    }

  }

  *flagsp = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_dsdigest_fromtext(dns_dsdigest_t *dsdigestp, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, dsdigests, 0xff));

  *dsdigestp = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_dsdigest_totext(dns_dsdigest_t dsdigest, isc_buffer_t *target) {

  return dns_mnemonic_totext(dsdigest, target, dsdigests);

}

void

dns_dsdigest_format(dns_dsdigest_t typ, char *cp, unsigned int size) {

  isc_buffer_t b;

  isc_region_t r;

  isc_result_t result;

  REQUIRE(cp != NULL && size > 0);

  isc_buffer_init(&b, cp, size - 1);

  result = dns_dsdigest_totext(typ, &b);

  isc_buffer_usedregion(&b, &r);

  r.base[r.length] = 0;

  if (result != ISC_R_SUCCESS) {

    r.base[0] = 0;

  }

}

/*

 * DSYNC Scheme

 */

isc_result_t

dns_dsyncscheme_fromtext(dns_dsyncscheme_t *schemep, isc_textregion_t *source) {

  unsigned int value;

  REQUIRE(schemep != NULL);

  RETERR(dns_mnemonic_fromtext(&value, source, dsyncschemes, 0xff));

  *schemep = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dns_dsyncscheme_totext(dns_dsyncscheme_t scheme, isc_buffer_t *target) {

  return dns_mnemonic_totext(scheme, target, dsyncschemes);

}

void

dns_dsyncscheme_format(dns_dsyncscheme_t scheme, char *cp, unsigned int size) {

  isc_buffer_t b;

  isc_region_t r;

  isc_result_t result;

  REQUIRE(cp != NULL && size > 0);

  isc_buffer_init(&b, cp, size - 1);

  result = dns_dsyncscheme_totext(scheme, &b);

  isc_buffer_usedregion(&b, &r);

  r.base[r.length] = 0;

  if (result != ISC_R_SUCCESS) {

    r.base[0] = 0;

  }

}

/*

 * This uses lots of hard coded values, but how often do we actually

 * add classes?

 */

isc_result_t

dns_rdataclass_fromtext(dns_rdataclass_t *classp, isc_textregion_t *source) {

#define COMPARE(string, rdclass)                                      \

  if (((sizeof(string) - 1) == source->length) &&               \

      (strncasecmp(source->base, string, source->length) == 0)) \

  {                                                             \

    *classp = rdclass;                                    \

    return (ISC_R_SUCCESS);                               \

  }

  switch (isc_ascii_tolower(source->base[0])) {

  case 'a':

    COMPARE("any", dns_rdataclass_any);

    break;

  case 'c':

    /*

     * RFC1035 says the mnemonic for the CHAOS class is CH,

     * but historical BIND practice is to call it CHAOS.

     * We will accept both forms, but only generate CH.

     */

    COMPARE("ch", dns_rdataclass_chaos);

    COMPARE("chaos", dns_rdataclass_chaos);

    if (source->length > 5 &&

        source->length < (5 + sizeof("65000")) &&

        strncasecmp("class", source->base, 5) == 0)

    {

      char buf[sizeof("65000")];

      char *endp;

      unsigned int val;

      /*

       * source->base is not required to be NUL terminated.

       * Copy up to remaining bytes and NUL terminate.

       */

      snprintf(buf, sizeof(buf), "%.*s",

         (int)(source->length - 5), source->base + 5);

      val = strtoul(buf, &endp, 10);

      if (*endp == '\0' && val <= 0xffff) {

        *classp = (dns_rdataclass_t)val;

        return ISC_R_SUCCESS;

      }

    }

    break;

  case 'h':

    COMPARE("hs", dns_rdataclass_hs);

    COMPARE("hesiod", dns_rdataclass_hs);

    break;

  case 'i':

    COMPARE("in", dns_rdataclass_in);

    break;

  case 'n':

    COMPARE("none", dns_rdataclass_none);

    break;

  case 'r':

    COMPARE("reserved0", dns_rdataclass_reserved0);

    break;

  }

#undef COMPARE

  return DNS_R_UNKNOWN;

}

isc_result_t

dns_rdataclass_totext(dns_rdataclass_t rdclass, isc_buffer_t *target) {

  switch (rdclass) {

  case dns_rdataclass_any:

    return str_totext("ANY", target);

  case dns_rdataclass_chaos:

    return str_totext("CH", target);

  case dns_rdataclass_hs:

    return str_totext("HS", target);

  case dns_rdataclass_in:

    return str_totext("IN", target);

  case dns_rdataclass_none:

    return str_totext("NONE", target);

  case dns_rdataclass_reserved0:

    return str_totext("RESERVED0", target);

  default:

    return dns_rdataclass_tounknowntext(rdclass, target);

  }

}

isc_result_t

dns_rdataclass_tounknowntext(dns_rdataclass_t rdclass, isc_buffer_t *target) {

  char buf[sizeof("CLASS65535")];

  snprintf(buf, sizeof(buf), "CLASS%u", rdclass);

  return str_totext(buf, target);

}

void

dns_rdataclass_format(dns_rdataclass_t rdclass, char *array,

          unsigned int size) {

  isc_result_t result;

  isc_buffer_t buf;

  if (size == 0U) {

    return;

  }

  isc_buffer_init(&buf, array, size);

  result = dns_rdataclass_totext(rdclass, &buf);

  /*

   * Null terminate.

   */

  if (result == ISC_R_SUCCESS) {

    if (isc_buffer_availablelength(&buf) >= 1) {

      isc_buffer_putuint8(&buf, 0);

    } else {

      result = ISC_R_NOSPACE;

    }

  }

  if (result != ISC_R_SUCCESS) {

    strlcpy(array, "<unknown>", size);

  }

}

isc_result_t

dst_algorithm_fromtext(dst_algorithm_t *dstalgp, isc_textregion_t *source) {

  unsigned int value;

  RETERR(dns_mnemonic_fromtext(&value, source, dstalgorithms, 255));

  *dstalgp = value;

  return ISC_R_SUCCESS;

}

isc_result_t

dst_algorithm_totext(dst_algorithm_t alg, isc_buffer_t *target) {

  return dns_mnemonic_totext(alg, target, dstalgorithms);

}

void

dst_algorithm_format(dst_algorithm_t alg, char *cp, unsigned int size) {

  isc_buffer_t b;

  isc_region_t r;

  isc_result_t result;

  REQUIRE(cp != NULL && size > 0);

  isc_buffer_init(&b, cp, size - 1);

  result = dst_algorithm_totext(alg, &b);

  isc_buffer_usedregion(&b, &r);

  r.base[r.length] = 0;

  if (result != ISC_R_SUCCESS) {

    r.base[0] = 0;

  }

}