// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Unified UUID/GUID definition
   *

   * Copyright (C) 2009, 2016 Intel Corp.

   *	Huang Ying <ying.huang@intel.com>

   */
  
  #include <linux/kernel.h>

  #include <linux/ctype.h>
  #include <linux/errno.h>

  #include <linux/export.h>

  #include <linux/uuid.h>
  #include <linux/random.h>

  const guid_t guid_null;
  EXPORT_SYMBOL(guid_null);
  const uuid_t uuid_null;
  EXPORT_SYMBOL(uuid_null);

  const u8 guid_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};

  const u8 uuid_index[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};

  /**
   * generate_random_uuid - generate a random UUID
   * @uuid: where to put the generated UUID
   *

   * Random UUID interface
   *

   * Used to create a Boot ID or a filesystem UUID/GUID, but can be
   * useful for other kernel drivers.

   */
  void generate_random_uuid(unsigned char uuid[16])
  {
  	get_random_bytes(uuid, 16);
  	/* Set UUID version to 4 --- truly random generation */
  	uuid[6] = (uuid[6] & 0x0F) | 0x40;
  	/* Set the UUID variant to DCE */
  	uuid[8] = (uuid[8] & 0x3F) | 0x80;
  }
  EXPORT_SYMBOL(generate_random_uuid);

  void generate_random_guid(unsigned char guid[16])
  {
  	get_random_bytes(guid, 16);
  	/* Set GUID version to 4 --- truly random generation */
  	guid[7] = (guid[7] & 0x0F) | 0x40;
  	/* Set the GUID variant to DCE */
  	guid[8] = (guid[8] & 0x3F) | 0x80;
  }
  EXPORT_SYMBOL(generate_random_guid);

  static void __uuid_gen_common(__u8 b[16])
  {

  	prandom_bytes(b, 16);

  	/* reversion 0b10 */
  	b[8] = (b[8] & 0x3F) | 0x80;
  }

  void guid_gen(guid_t *lu)

  {
  	__uuid_gen_common(lu->b);
  	/* version 4 : random generation */
  	lu->b[7] = (lu->b[7] & 0x0F) | 0x40;
  }

  EXPORT_SYMBOL_GPL(guid_gen);

  void uuid_gen(uuid_t *bu)

  {
  	__uuid_gen_common(bu->b);
  	/* version 4 : random generation */
  	bu->b[6] = (bu->b[6] & 0x0F) | 0x40;
  }

  EXPORT_SYMBOL_GPL(uuid_gen);

  
  /**

   * uuid_is_valid - checks if a UUID string is valid
   * @uuid:	UUID string to check
   *
   * Description:
   * It checks if the UUID string is following the format:
   *	xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
   *
   * where x is a hex digit.
   *
   * Return: true if input is valid UUID string.
   */

  bool uuid_is_valid(const char *uuid)
  {
  	unsigned int i;
  
  	for (i = 0; i < UUID_STRING_LEN; i++) {
  		if (i == 8 || i == 13 || i == 18 || i == 23) {
  			if (uuid[i] != '-')
  				return false;
  		} else if (!isxdigit(uuid[i])) {
  			return false;
  		}
  	}
  
  	return true;
  }
  EXPORT_SYMBOL(uuid_is_valid);

  static int __uuid_parse(const char *uuid, __u8 b[16], const u8 ei[16])

  {
  	static const u8 si[16] = {0,2,4,6,9,11,14,16,19,21,24,26,28,30,32,34};
  	unsigned int i;
  
  	if (!uuid_is_valid(uuid))
  		return -EINVAL;
  
  	for (i = 0; i < 16; i++) {

  		int hi = hex_to_bin(uuid[si[i] + 0]);
  		int lo = hex_to_bin(uuid[si[i] + 1]);

  
  		b[ei[i]] = (hi << 4) | lo;
  	}
  
  	return 0;
  }

  int guid_parse(const char *uuid, guid_t *u)

  {

  	return __uuid_parse(uuid, u->b, guid_index);

  }

  EXPORT_SYMBOL(guid_parse);

  int uuid_parse(const char *uuid, uuid_t *u)

  {

  	return __uuid_parse(uuid, u->b, uuid_index);

  }

  EXPORT_SYMBOL(uuid_parse);