FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_uuid.c
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: releng/9.2/sys/kern/kern_uuid.c 233200 2012-03-19 20:49:16Z jhb $");
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_RLOCK(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_RUNLOCK(ifp);
109 IFNET_RUNLOCK_NOSLEEP();
110 CURVNET_RESTORE();
111 return;
112 }
113 }
114 IF_ADDR_RUNLOCK(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 sys_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 }
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