/*

 * Universally Unique IDentifier (UUID)

 * Copyright (c) 2008, Jouni Malinen <j@w1.fi>

 *

 * This software may be distributed under the terms of the BSD license.

 * See README for more details.

 */

#include "includes.h"

#include "common.h"

#include "crypto/sha256.h"

#include "uuid.h"

int uuid_str2bin(const char *str, u8 *bin)

{

  const char *pos;

  u8 *opos;

  pos = str;

  opos = bin;

  if (hexstr2bin(pos, opos, 4))

    return -1;

  pos += 8;

  opos += 4;

  if (*pos++ != '-' || hexstr2bin(pos, opos, 2))

    return -1;

  pos += 4;

  opos += 2;

  if (*pos++ != '-' || hexstr2bin(pos, opos, 2))

    return -1;

  pos += 4;

  opos += 2;

  if (*pos++ != '-' || hexstr2bin(pos, opos, 2))

    return -1;

  pos += 4;

  opos += 2;

  if (*pos++ != '-' || hexstr2bin(pos, opos, 6))

    return -1;

  return 0;

}

int uuid_bin2str(const u8 *bin, char *str, size_t max_len)

{

  int len;

  len = os_snprintf(str, max_len, "%02x%02x%02x%02x-%02x%02x-%02x%02x-"

        "%02x%02x-%02x%02x%02x%02x%02x%02x",

        bin[0], bin[1], bin[2], bin[3],

        bin[4], bin[5], bin[6], bin[7],

        bin[8], bin[9], bin[10], bin[11],

        bin[12], bin[13], bin[14], bin[15]);

  if (os_snprintf_error(max_len, len))

    return -1;

  return 0;

}

int is_nil_uuid(const u8 *uuid)

{

  int i;

  for (i = 0; i < UUID_LEN; i++)

    if (uuid[i])

      return 0;

  return 1;

}

int uuid_random(u8 *uuid)

{

  struct os_time t;

  u8 hash[SHA256_MAC_LEN];

  /* Use HMAC-SHA256 and timestamp as context to avoid exposing direct

   * os_get_random() output in the UUID field. */

  os_get_time(&t);

  if (os_get_random(uuid, UUID_LEN) < 0 ||

      hmac_sha256(uuid, UUID_LEN, (const u8 *) &t, sizeof(t), hash) < 0)

    return -1;

  os_memcpy(uuid, hash, UUID_LEN);

  /* Version: 4 = random */

  uuid[6] = (4 << 4) | (uuid[6] & 0x0f);

  /* Variant specified in RFC 4122 */

  uuid[8] = 0x80 | (uuid[8] & 0x3f);

  return 0;

}