lib/uuid.c

   1 /*
   2  * Unified UUID/GUID definition
   3  *
   4  * Copyright (C) 2009, Intel Corp.
   5  *      Huang Ying <ying.huang@intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version
   9  * 2 as published by the Free Software Foundation;
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/uuid.h>
  24 #include <linux/random.h>
  25
  26 static void __uuid_gen_common(__u8 b[16])
  27 {
  28         int i;
  29         u32 r;
  30
  31         for (i = 0; i < 4; i++) {
  32                 r = random32();
  33                 memcpy(b + i * 4, &r, 4);
  34         }
  35         /* reversion 0b10 */
  36         b[8] = (b[8] & 0x3F) | 0x80;
  37 }
  38
  39 void uuid_le_gen(uuid_le *lu)
  40 {
  41         __uuid_gen_common(lu->b);
  42         /* version 4 : random generation */
  43         lu->b[7] = (lu->b[7] & 0x0F) | 0x40;
  44 }
  45 EXPORT_SYMBOL_GPL(uuid_le_gen);
  46
  47 void uuid_be_gen(uuid_be *bu)
  48 {
  49         __uuid_gen_common(bu->b);
  50         /* version 4 : random generation */
  51         bu->b[6] = (bu->b[6] & 0x0F) | 0x40;
  52 }
  53 EXPORT_SYMBOL_GPL(uuid_be_gen);