linux/lib/uuid.c

/*
 * Unified UUID/GUID definition
 *
 * Copyright (C) 2009, 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

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

/***************************************************************
 * 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);