1/*	$OpenBSD: uuid.c,v 1.6 2018/04/26 12:42:51 guenther Exp $ */
2/*
3 * Copyright (c) 2002, Stockholms Universitet
4 * (Stockholm University, Stockholm Sweden)
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 *
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * 3. Neither the name of the university nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
23 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
26 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
31 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32 * POSSIBILITY OF SUCH DAMAGE.
33 */
34
35/*
36 * NCS/DCE/AFS/GUID generator
37 *
38 *  for more information about DCE UUID, see
39 *  <http://www.opengroup.org/onlinepubs/9629399/apdxa.htm>
40 *
41 *  Note, the Microsoft GUID is a DCE UUID, but it seems like they
42 *  folded in the seq num with the node part. That would explain how
43 *  the reserved field have a bit pattern 110 when reserved is a 2 bit
44 *  field.
45 *
46 *  XXX should hash the node address for privacy issues
47 */
48
49#include <sys/types.h>
50#include <sys/socket.h>
51#include <sys/time.h>
52#include <netinet/in.h>
53#include <net/if.h>
54#include <net/if_types.h>
55#include <net/if_dl.h>
56
57#include <fcntl.h>
58#include <ifaddrs.h>
59#include <stdio.h>
60#include <stdlib.h>
61#include <string.h>
62#include <unistd.h>
63
64#include "uuid.h"
65
66static uint32_t seq_num;
67static struct timeval last_time;
68static int32_t counter;
69static char nodeaddr[6];
70
71enum { UUID_NODE_MULTICAST = 0x80 };
72
73static int
74time_cmp(struct timeval *tv1, struct timeval *tv2)
75{
76    if (tv1->tv_sec > tv2->tv_sec)
77	return -1;
78    if (tv1->tv_sec < tv2->tv_sec)
79	return 1;
80    if (tv1->tv_usec > tv2->tv_usec)
81	return -1;
82    if (tv1->tv_usec < tv2->tv_usec)
83	return 1;
84    return 0;
85}
86
87static void
88get_node_addr(char *addr)
89{
90    struct ifaddrs *ifa, *ifa0;
91    int found_mac = 0;
92
93    if (getifaddrs(&ifa0) != 0)
94	ifa0 = NULL;
95
96    for (ifa = ifa0; ifa != NULL && !found_mac; ifa = ifa->ifa_next) {
97	if (ifa->ifa_addr == NULL)
98	    continue;
99
100#if IFF_LOOPBACK
101	if (ifa->ifa_flags & IFF_LOOPBACK)
102	    continue;
103#endif
104
105	switch (ifa->ifa_addr->sa_family) {
106#ifdef AF_LINK
107	case AF_LINK: {
108	    struct sockaddr_dl *dl = (struct sockaddr_dl *)ifa->ifa_addr;
109
110	    switch (dl->sdl_type) {
111	    case IFT_ETHER:
112	    case IFT_FDDI:
113		if (dl->sdl_alen == 6) {
114		    memcpy(addr, LLADDR(dl), 6);
115		    found_mac = 1;
116		}
117	    }
118
119	}
120#endif
121	default:
122	    break;
123	}
124    }
125
126    if (ifa0 != NULL)
127	freeifaddrs(ifa0);
128
129    if (!found_mac) {
130	/*
131	 * Set the multicast bit to make sure we won't collide with an
132	 * allocated (mac) address.
133	 */
134	arc4random_buf(addr, 6);
135	addr[0] |= UUID_NODE_MULTICAST;
136    }
137    return;
138}
139
140/*
141 *    Creates a new UUID.
142 */
143
144void
145uuid_create(afsUUID *uuid)
146{
147    static int uuid_inited = 0;
148    struct timeval tv;
149    int ret, got_time;
150    uint64_t dce_time;
151
152    if (uuid_inited == 0) {
153	gettimeofday(&last_time, NULL);
154	seq_num = arc4random();
155	get_node_addr(nodeaddr);
156	uuid_inited = 1;
157    }
158
159    gettimeofday(&tv, NULL);
160
161    got_time = 0;
162
163    do {
164	ret = time_cmp(&tv, &last_time);
165	if (ret < 0) {
166	    /* Time went backward, just inc seq_num and be done.
167	     * seq_num is 6 + 8 bit field it the uuid, so let it wrap
168	     * around. don't let it be zero.
169	     */
170	    seq_num = (seq_num + 1) & 0x3fff ;
171	    if (seq_num == 0)
172		seq_num++;
173	    got_time = 1;
174	    counter = 0;
175	    last_time = tv;
176	} else if (ret > 0) {
177	    /* time went forward, reset counter and be happy */
178	    last_time = tv;
179	    counter = 0;
180	    got_time = 1;
181	} else {
182#define UUID_MAX_HZ (1) /* make this bigger fix you have larger tickrate */
183#define MULTIPLIER_100_NANO_SEC 10
184	    if (++counter < UUID_MAX_HZ * MULTIPLIER_100_NANO_SEC)
185		got_time = 1;
186	}
187    } while(!got_time);
188
189    /*
190     * now shift time to dce_time, epoch 00:00:00:00, 15 October 1582
191     * dce time ends year ~3400, so start to worry now
192     */
193
194    dce_time = tv.tv_usec * MULTIPLIER_100_NANO_SEC + counter;
195    dce_time += ((uint64_t)tv.tv_sec) * 10000000;
196    dce_time += (((uint64_t)0x01b21dd2) << 32) + 0x13814000;
197
198    uuid->time_low = dce_time & 0xffffffff;
199    uuid->time_mid = 0xffff & (dce_time >> 32);
200    uuid->time_hi_and_version = 0x0fff & (dce_time >> 48);
201
202    uuid->time_hi_and_version |= (1 << 12);
203
204    uuid->clock_seq_low = seq_num & 0xff;
205    uuid->clock_seq_hi_and_reserved = (seq_num >> 8) & 0x3f;
206    uuid->clock_seq_hi_and_reserved |= 0x80; /* dce variant */
207
208    memcpy(uuid->node, nodeaddr, 6);
209}
210
211/*
212 *    Converts a UUID from binary representation to a string representation.
213 */
214
215void
216uuid_to_string(const afsUUID *uuid, char *str, size_t strsz)
217{
218    snprintf(str, strsz,
219	     "%08lx-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
220	     uuid->time_low,
221	     uuid->time_mid,
222	     uuid->time_hi_and_version,
223	     (unsigned char)uuid->clock_seq_hi_and_reserved,
224	     (unsigned char)uuid->clock_seq_low,
225	     (unsigned char)uuid->node[0],
226	     (unsigned char)uuid->node[1],
227	     (unsigned char)uuid->node[2],
228	     (unsigned char)uuid->node[3],
229	     (unsigned char)uuid->node[4],
230	     (unsigned char)uuid->node[5]);
231}
232
233
234#ifdef TEST
235int
236main(int argc, char **argv)
237{
238    char str[1000];
239    afsUUID u1, u2;
240
241    uuid_create(&u1);
242
243    uuid_to_string(&u1, str, sizeof(str));
244
245    printf("u: %s\n", str);
246
247    if (uuid_from_string(str, &u2)) {
248	printf("failed to parse\n");
249	return 0;
250    }
251
252    if (bcmp(&u1, &u2, sizeof(u1)) != 0)
253	printf("u1 != u2\n");
254
255    return 0;
256}
257#endif
258