1/*
2 * Unified UUID/GUID definition
3 *
4 * Copyright (C) 2009, 2016 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
17#include <linux/kernel.h>
18#include <linux/ctype.h>
19#include <linux/errno.h>
20#include <linux/export.h>
21#include <linux/uuid.h>
22#include <linux/random.h>
23
24const guid_t guid_null;
25EXPORT_SYMBOL(guid_null);
26const uuid_t uuid_null;
27EXPORT_SYMBOL(uuid_null);
28
29const u8 guid_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
30const u8 uuid_index[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
31
32/**
33 * generate_random_uuid - generate a random UUID
34 * @uuid: where to put the generated UUID
35 *
36 * Random UUID interface
37 *
38 * Used to create a Boot ID or a filesystem UUID/GUID, but can be
39 * useful for other kernel drivers.
40 */
41void generate_random_uuid(unsigned char uuid[16])
42{
43 get_random_bytes(uuid, 16);
44 /* Set UUID version to 4 --- truly random generation */
45 uuid[6] = (uuid[6] & 0x0F) | 0x40;
46 /* Set the UUID variant to DCE */
47 uuid[8] = (uuid[8] & 0x3F) | 0x80;
48}
49EXPORT_SYMBOL(generate_random_uuid);
50
51static void __uuid_gen_common(__u8 b[16])
52{
53 prandom_bytes(b, 16);
54 /* reversion 0b10 */
55 b[8] = (b[8] & 0x3F) | 0x80;
56}
57
58void guid_gen(guid_t *lu)
59{
60 __uuid_gen_common(lu->b);
61 /* version 4 : random generation */
62 lu->b[7] = (lu->b[7] & 0x0F) | 0x40;
63}
64EXPORT_SYMBOL_GPL(guid_gen);
65
66void uuid_gen(uuid_t *bu)
67{
68 __uuid_gen_common(bu->b);
69 /* version 4 : random generation */
70 bu->b[6] = (bu->b[6] & 0x0F) | 0x40;
71}
72EXPORT_SYMBOL_GPL(uuid_gen);
73
74/**
75 * uuid_is_valid - checks if a UUID string is valid
76 * @uuid: UUID string to check
77 *
78 * Description:
79 * It checks if the UUID string is following the format:
80 * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
81 *
82 * where x is a hex digit.
83 *
84 * Return: true if input is valid UUID string.
85 */
86bool uuid_is_valid(const char *uuid)
87{
88 unsigned int i;
89
90 for (i = 0; i < UUID_STRING_LEN; i++) {
91 if (i == 8 || i == 13 || i == 18 || i == 23) {
92 if (uuid[i] != '-')
93 return false;
94 } else if (!isxdigit(uuid[i])) {
95 return false;
96 }
97 }
98
99 return true;
100}
101EXPORT_SYMBOL(uuid_is_valid);
102
103static int __uuid_parse(const char *uuid, __u8 b[16], const u8 ei[16])
104{
105 static const u8 si[16] = {0,2,4,6,9,11,14,16,19,21,24,26,28,30,32,34};
106 unsigned int i;
107
108 if (!uuid_is_valid(uuid))
109 return -EINVAL;
110
111 for (i = 0; i < 16; i++) {
112 int hi = hex_to_bin(uuid[si[i] + 0]);
113 int lo = hex_to_bin(uuid[si[i] + 1]);
114
115 b[ei[i]] = (hi << 4) | lo;
116 }
117
118 return 0;
119}
120
121int guid_parse(const char *uuid, guid_t *u)
122{
123 return __uuid_parse(uuid, u->b, guid_index);
124}
125EXPORT_SYMBOL(guid_parse);
126
127int uuid_parse(const char *uuid, uuid_t *u)
128{
129 return __uuid_parse(uuid, u->b, uuid_index);
130}
131EXPORT_SYMBOL(uuid_parse);
132