xref: /freebsd/sys/kern/kern_uuid.c (revision 7aa383846770374466b1dcb2cefd71bde9acf463)
1 /*-
2  * Copyright (c) 2002 Marcel Moolenaar
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/endian.h>
32 #include <sys/kernel.h>
33 #include <sys/lock.h>
34 #include <sys/mutex.h>
35 #include <sys/sbuf.h>
36 #include <sys/socket.h>
37 #include <sys/sysproto.h>
38 #include <sys/systm.h>
39 #include <sys/jail.h>
40 #include <sys/uuid.h>
41 
42 #include <net/if.h>
43 #include <net/if_dl.h>
44 #include <net/if_types.h>
45 #include <net/vnet.h>
46 
47 /*
48  * See also:
49  *	http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
50  *	http://www.opengroup.org/onlinepubs/009629399/apdxa.htm
51  *
52  * Note that the generator state is itself an UUID, but the time and clock
53  * sequence fields are written in the native byte order.
54  */
55 
56 CTASSERT(sizeof(struct uuid) == 16);
57 
58 /* We use an alternative, more convenient representation in the generator. */
59 struct uuid_private {
60 	union {
61 		uint64_t	ll;		/* internal. */
62 		struct {
63 			uint32_t	low;
64 			uint16_t	mid;
65 			uint16_t	hi;
66 		} x;
67 	} time;
68 	uint16_t	seq;			/* Big-endian. */
69 	uint16_t	node[UUID_NODE_LEN>>1];
70 };
71 
72 CTASSERT(sizeof(struct uuid_private) == 16);
73 
74 static struct uuid_private uuid_last;
75 
76 static struct mtx uuid_mutex;
77 MTX_SYSINIT(uuid_lock, &uuid_mutex, "UUID generator mutex lock", MTX_DEF);
78 
79 /*
80  * Return the first MAC address we encounter or, if none was found,
81  * construct a sufficiently random multicast address. We don't try
82  * to return the same MAC address as previously returned. We always
83  * generate a new multicast address if no MAC address exists in the
84  * system.
85  * It would be nice to know if 'ifnet' or any of its sub-structures
86  * has been changed in any way. If not, we could simply skip the
87  * scan and safely return the MAC address we returned before.
88  */
89 static void
90 uuid_node(uint16_t *node)
91 {
92 	struct ifnet *ifp;
93 	struct ifaddr *ifa;
94 	struct sockaddr_dl *sdl;
95 	int i;
96 
97 	CURVNET_SET(TD_TO_VNET(curthread));
98 	IFNET_RLOCK_NOSLEEP();
99 	TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
100 		/* Walk the address list */
101 		IF_ADDR_LOCK(ifp);
102 		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
103 			sdl = (struct sockaddr_dl*)ifa->ifa_addr;
104 			if (sdl != NULL && sdl->sdl_family == AF_LINK &&
105 			    sdl->sdl_type == IFT_ETHER) {
106 				/* Got a MAC address. */
107 				bcopy(LLADDR(sdl), node, UUID_NODE_LEN);
108 				IF_ADDR_UNLOCK(ifp);
109 				IFNET_RUNLOCK_NOSLEEP();
110 				CURVNET_RESTORE();
111 				return;
112 			}
113 		}
114 		IF_ADDR_UNLOCK(ifp);
115 	}
116 	IFNET_RUNLOCK_NOSLEEP();
117 
118 	for (i = 0; i < (UUID_NODE_LEN>>1); i++)
119 		node[i] = (uint16_t)arc4random();
120 	*((uint8_t*)node) |= 0x01;
121 	CURVNET_RESTORE();
122 }
123 
124 /*
125  * Get the current time as a 60 bit count of 100-nanosecond intervals
126  * since 00:00:00.00, October 15,1582. We apply a magic offset to convert
127  * the Unix time since 00:00:00.00, January 1, 1970 to the date of the
128  * Gregorian reform to the Christian calendar.
129  */
130 static uint64_t
131 uuid_time(void)
132 {
133 	struct bintime bt;
134 	uint64_t time = 0x01B21DD213814000LL;
135 
136 	bintime(&bt);
137 	time += (uint64_t)bt.sec * 10000000LL;
138 	time += (10000000LL * (uint32_t)(bt.frac >> 32)) >> 32;
139 	return (time & ((1LL << 60) - 1LL));
140 }
141 
142 struct uuid *
143 kern_uuidgen(struct uuid *store, size_t count)
144 {
145 	struct uuid_private uuid;
146 	uint64_t time;
147 	size_t n;
148 
149 	mtx_lock(&uuid_mutex);
150 
151 	uuid_node(uuid.node);
152 	time = uuid_time();
153 
154 	if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid.node[0] ||
155 	    uuid_last.node[1] != uuid.node[1] ||
156 	    uuid_last.node[2] != uuid.node[2])
157 		uuid.seq = (uint16_t)arc4random() & 0x3fff;
158 	else if (uuid_last.time.ll >= time)
159 		uuid.seq = (uuid_last.seq + 1) & 0x3fff;
160 	else
161 		uuid.seq = uuid_last.seq;
162 
163 	uuid_last = uuid;
164 	uuid_last.time.ll = (time + count - 1) & ((1LL << 60) - 1LL);
165 
166 	mtx_unlock(&uuid_mutex);
167 
168 	/* Set sequence and variant and deal with byte order. */
169 	uuid.seq = htobe16(uuid.seq | 0x8000);
170 
171 	for (n = 0; n < count; n++) {
172 		/* Set time and version (=1). */
173 		uuid.time.x.low = (uint32_t)time;
174 		uuid.time.x.mid = (uint16_t)(time >> 32);
175 		uuid.time.x.hi = ((uint16_t)(time >> 48) & 0xfff) | (1 << 12);
176 		store[n] = *(struct uuid *)&uuid;
177 		time++;
178 	}
179 
180 	return (store);
181 }
182 
183 #ifndef _SYS_SYSPROTO_H_
184 struct uuidgen_args {
185 	struct uuid *store;
186 	int	count;
187 };
188 #endif
189 int
190 uuidgen(struct thread *td, struct uuidgen_args *uap)
191 {
192 	struct uuid *store;
193 	size_t count;
194 	int error;
195 
196 	/*
197 	 * Limit the number of UUIDs that can be created at the same time
198 	 * to some arbitrary number. This isn't really necessary, but I
199 	 * like to have some sort of upper-bound that's less than 2G :-)
200 	 * XXX probably needs to be tunable.
201 	 */
202 	if (uap->count < 1 || uap->count > 2048)
203 		return (EINVAL);
204 
205 	count = uap->count;
206 	store = malloc(count * sizeof(struct uuid), M_TEMP, M_WAITOK);
207 	kern_uuidgen(store, count);
208 	error = copyout(store, uap->store, count * sizeof(struct uuid));
209 	free(store, M_TEMP);
210 	return (error);
211 }
212 
213 int
214 snprintf_uuid(char *buf, size_t sz, struct uuid *uuid)
215 {
216 	struct uuid_private *id;
217 	int cnt;
218 
219 	id = (struct uuid_private *)uuid;
220 	cnt = snprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x",
221 	    id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq),
222 	    be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2]));
223 	return (cnt);
224 }
225 
226 int
227 printf_uuid(struct uuid *uuid)
228 {
229 	char buf[38];
230 
231 	snprintf_uuid(buf, sizeof(buf), uuid);
232 	return (printf("%s", buf));
233 }
234 
235 int
236 sbuf_printf_uuid(struct sbuf *sb, struct uuid *uuid)
237 {
238 	char buf[38];
239 
240 	snprintf_uuid(buf, sizeof(buf), uuid);
241 	return (sbuf_printf(sb, "%s", buf));
242 }
243 
244 /*
245  * Encode/Decode UUID into byte-stream.
246  *   http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
247  *
248  * 0                   1                   2                   3
249  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
250  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
251  *  |                          time_low                             |
252  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
253  *  |       time_mid                |         time_hi_and_version   |
254  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
255  *  |clk_seq_hi_res |  clk_seq_low  |         node (0-1)            |
256  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
257  *  |                         node (2-5)                            |
258  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
259  */
260 
261 void
262 le_uuid_enc(void *buf, struct uuid const *uuid)
263 {
264 	u_char *p;
265 	int i;
266 
267 	p = buf;
268 	le32enc(p, uuid->time_low);
269 	le16enc(p + 4, uuid->time_mid);
270 	le16enc(p + 6, uuid->time_hi_and_version);
271 	p[8] = uuid->clock_seq_hi_and_reserved;
272 	p[9] = uuid->clock_seq_low;
273 	for (i = 0; i < _UUID_NODE_LEN; i++)
274 		p[10 + i] = uuid->node[i];
275 }
276 
277 void
278 le_uuid_dec(void const *buf, struct uuid *uuid)
279 {
280 	u_char const *p;
281 	int i;
282 
283 	p = buf;
284 	uuid->time_low = le32dec(p);
285 	uuid->time_mid = le16dec(p + 4);
286 	uuid->time_hi_and_version = le16dec(p + 6);
287 	uuid->clock_seq_hi_and_reserved = p[8];
288 	uuid->clock_seq_low = p[9];
289 	for (i = 0; i < _UUID_NODE_LEN; i++)
290 		uuid->node[i] = p[10 + i];
291 }
292 
293 void
294 be_uuid_enc(void *buf, struct uuid const *uuid)
295 {
296 	u_char *p;
297 	int i;
298 
299 	p = buf;
300 	be32enc(p, uuid->time_low);
301 	be16enc(p + 4, uuid->time_mid);
302 	be16enc(p + 6, uuid->time_hi_and_version);
303 	p[8] = uuid->clock_seq_hi_and_reserved;
304 	p[9] = uuid->clock_seq_low;
305 	for (i = 0; i < _UUID_NODE_LEN; i++)
306 		p[10 + i] = uuid->node[i];
307 }
308 
309 void
310 be_uuid_dec(void const *buf, struct uuid *uuid)
311 {
312 	u_char const *p;
313 	int i;
314 
315 	p = buf;
316 	uuid->time_low = be32dec(p);
317 	uuid->time_mid = le16dec(p + 4);
318 	uuid->time_hi_and_version = be16dec(p + 6);
319 	uuid->clock_seq_hi_and_reserved = p[8];
320 	uuid->clock_seq_low = p[9];
321 	for (i = 0; i < _UUID_NODE_LEN; i++)
322 		uuid->node[i] = p[10 + i];
323 }
324 
325 int
326 parse_uuid(const char *str, struct uuid *uuid)
327 {
328 	u_int c[11];
329 	int n;
330 
331 	/* An empty string represents a nil UUID. */
332 	if (*str == '\0') {
333 		bzero(uuid, sizeof(*uuid));
334 		return (0);
335 	}
336 
337 	/* The UUID string representation has a fixed length. */
338 	if (strlen(str) != 36)
339 		return (EINVAL);
340 
341 	/*
342 	 * We only work with "new" UUIDs. New UUIDs have the form:
343 	 *      01234567-89ab-cdef-0123-456789abcdef
344 	 * The so called "old" UUIDs, which we don't support, have the form:
345 	 *      0123456789ab.cd.ef.01.23.45.67.89.ab
346 	 */
347 	if (str[8] != '-')
348 		return (EINVAL);
349 
350 	n = sscanf(str, "%8x-%4x-%4x-%2x%2x-%2x%2x%2x%2x%2x%2x", c + 0, c + 1,
351 	    c + 2, c + 3, c + 4, c + 5, c + 6, c + 7, c + 8, c + 9, c + 10);
352 	/* Make sure we have all conversions. */
353 	if (n != 11)
354 		return (EINVAL);
355 
356 	/* Successful scan. Build the UUID. */
357 	uuid->time_low = c[0];
358 	uuid->time_mid = c[1];
359 	uuid->time_hi_and_version = c[2];
360 	uuid->clock_seq_hi_and_reserved = c[3];
361 	uuid->clock_seq_low = c[4];
362 	for (n = 0; n < 6; n++)
363 		uuid->node[n] = c[n + 5];
364 
365 	/* Check semantics... */
366 	return (((c[3] & 0x80) != 0x00 &&		/* variant 0? */
367 	    (c[3] & 0xc0) != 0x80 &&			/* variant 1? */
368 	    (c[3] & 0xe0) != 0xc0) ? EINVAL : 0);	/* variant 2? */
369 }
370