uuid.c revision 107a9f161babc20daf915311146b0e864d3b4157 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <string.h>
18#include <arpa/inet.h>
19
20#include "ext4_utils.h"
21#include "sha1.h"
22#include "uuid.h"
23
24/* Definition from RFC-4122 */
25struct uuid {
26	u32 time_low;
27	u16 time_mid;
28	u16 time_hi_and_version;
29	u8 clk_seq_hi_res;
30	u8 clk_seq_low;
31	u16 node0_1;
32	u32 node2_5;
33};
34
35static void sha1_hash(const char *namespace, const char *name,
36	unsigned char sha1[SHA1_DIGEST_LENGTH])
37{
38	SHA1_CTX ctx;
39	SHA1Init(&ctx);
40	SHA1Update(&ctx, (const u8*)namespace, strlen(namespace));
41	SHA1Update(&ctx, (const u8*)name, strlen(name));
42	SHA1Final(sha1, &ctx);
43}
44
45void generate_uuid(const char *namespace, const char *name, u8 result[16])
46{
47	unsigned char sha1[SHA1_DIGEST_LENGTH];
48	struct uuid *uuid = (struct uuid *)result;
49
50	sha1_hash(namespace, name, (unsigned char*)sha1);
51	memcpy(uuid, sha1, sizeof(struct uuid));
52
53	uuid->time_low = ntohl(uuid->time_low);
54	uuid->time_mid = ntohs(uuid->time_mid);
55	uuid->time_hi_and_version = ntohs(uuid->time_hi_and_version);
56	uuid->time_hi_and_version &= 0x0FFF;
57	uuid->time_hi_and_version |= (5 << 12);
58	uuid->clk_seq_hi_res &= ~(1 << 6);
59	uuid->clk_seq_hi_res |= 1 << 7;
60}
61