/*
   * Unified UUID/GUID definition
   *

   * Copyright (C) 2009, 2016 Intel Corp.

   *	Huang Ying <ying.huang@intel.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License version
   * 2 as published by the Free Software Foundation;
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.

   */
  
  #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 u8 uuid_le_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
  EXPORT_SYMBOL(uuid_le_index);
  const u8 uuid_be_index[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
  EXPORT_SYMBOL(uuid_be_index);

  /***************************************************************
   * Random UUID interface
   *
   * Used here for a Boot ID, but can be useful for other kernel
   * drivers.
   ***************************************************************/
  
  /*
   * Generate random UUID
   */
  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);

  static void __uuid_gen_common(__u8 b[16])
  {

  	prandom_bytes(b, 16);

  	/* reversion 0b10 */
  	b[8] = (b[8] & 0x3F) | 0x80;
  }
  
  void uuid_le_gen(uuid_le *lu)
  {
  	__uuid_gen_common(lu->b);
  	/* version 4 : random generation */
  	lu->b[7] = (lu->b[7] & 0x0F) | 0x40;
  }
  EXPORT_SYMBOL_GPL(uuid_le_gen);
  
  void uuid_be_gen(uuid_be *bu)
  {
  	__uuid_gen_common(bu->b);
  	/* version 4 : random generation */
  	bu->b[6] = (bu->b[6] & 0x0F) | 0x40;
  }
  EXPORT_SYMBOL_GPL(uuid_be_gen);

  
  /**
    * uuid_is_valid - checks if UUID string 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_to_bin(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 uuid_le_to_bin(const char *uuid, uuid_le *u)
  {
  	return __uuid_to_bin(uuid, u->b, uuid_le_index);
  }
  EXPORT_SYMBOL(uuid_le_to_bin);
  
  int uuid_be_to_bin(const char *uuid, uuid_be *u)
  {
  	return __uuid_to_bin(uuid, u->b, uuid_be_index);
  }
  EXPORT_SYMBOL(uuid_be_to_bin);