kern_uuid.c revision 196019
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: head/sys/kern/kern_uuid.c 196019 2009-08-01 19:26:27Z rwatson $"); 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/uuid.h> 40 41#include <net/if.h> 42#include <net/if_dl.h> 43#include <net/if_types.h> 44#include <net/vnet.h> 45 46/* 47 * See also: 48 * http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt 49 * http://www.opengroup.org/onlinepubs/009629399/apdxa.htm 50 * 51 * Note that the generator state is itself an UUID, but the time and clock 52 * sequence fields are written in the native byte order. 53 */ 54 55CTASSERT(sizeof(struct uuid) == 16); 56 57/* We use an alternative, more convenient representation in the generator. */ 58struct uuid_private { 59 union { 60 uint64_t ll; /* internal. */ 61 struct { 62 uint32_t low; 63 uint16_t mid; 64 uint16_t hi; 65 } x; 66 } time; 67 uint16_t seq; /* Big-endian. */ 68 uint16_t node[UUID_NODE_LEN>>1]; 69}; 70 71CTASSERT(sizeof(struct uuid_private) == 16); 72 73static struct uuid_private uuid_last; 74 75static struct mtx uuid_mutex; 76MTX_SYSINIT(uuid_lock, &uuid_mutex, "UUID generator mutex lock", MTX_DEF); 77 78/* 79 * Return the first MAC address we encounter or, if none was found, 80 * construct a sufficiently random multicast address. We don't try 81 * to return the same MAC address as previously returned. We always 82 * generate a new multicast address if no MAC address exists in the 83 * system. 84 * It would be nice to know if 'ifnet' or any of its sub-structures 85 * has been changed in any way. If not, we could simply skip the 86 * scan and safely return the MAC address we returned before. 87 */ 88static void 89uuid_node(uint16_t *node) 90{ 91 struct ifnet *ifp; 92 struct ifaddr *ifa; 93 struct sockaddr_dl *sdl; 94 int i; 95 96 IFNET_RLOCK(); 97 TAILQ_FOREACH(ifp, &V_ifnet, if_link) { 98 /* Walk the address list */ 99 IF_ADDR_LOCK(ifp); 100 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { 101 sdl = (struct sockaddr_dl*)ifa->ifa_addr; 102 if (sdl != NULL && sdl->sdl_family == AF_LINK && 103 sdl->sdl_type == IFT_ETHER) { 104 /* Got a MAC address. */ 105 bcopy(LLADDR(sdl), node, UUID_NODE_LEN); 106 IF_ADDR_UNLOCK(ifp); 107 IFNET_RUNLOCK(); 108 return; 109 } 110 } 111 IF_ADDR_UNLOCK(ifp); 112 } 113 IFNET_RUNLOCK(); 114 115 for (i = 0; i < (UUID_NODE_LEN>>1); i++) 116 node[i] = (uint16_t)arc4random(); 117 *((uint8_t*)node) |= 0x01; 118} 119 120/* 121 * Get the current time as a 60 bit count of 100-nanosecond intervals 122 * since 00:00:00.00, October 15,1582. We apply a magic offset to convert 123 * the Unix time since 00:00:00.00, January 1, 1970 to the date of the 124 * Gregorian reform to the Christian calendar. 125 */ 126static uint64_t 127uuid_time(void) 128{ 129 struct bintime bt; 130 uint64_t time = 0x01B21DD213814000LL; 131 132 bintime(&bt); 133 time += (uint64_t)bt.sec * 10000000LL; 134 time += (10000000LL * (uint32_t)(bt.frac >> 32)) >> 32; 135 return (time & ((1LL << 60) - 1LL)); 136} 137 138struct uuid * 139kern_uuidgen(struct uuid *store, size_t count) 140{ 141 struct uuid_private uuid; 142 uint64_t time; 143 size_t n; 144 145 mtx_lock(&uuid_mutex); 146 147 uuid_node(uuid.node); 148 time = uuid_time(); 149 150 if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid.node[0] || 151 uuid_last.node[1] != uuid.node[1] || 152 uuid_last.node[2] != uuid.node[2]) 153 uuid.seq = (uint16_t)arc4random() & 0x3fff; 154 else if (uuid_last.time.ll >= time) 155 uuid.seq = (uuid_last.seq + 1) & 0x3fff; 156 else 157 uuid.seq = uuid_last.seq; 158 159 uuid_last = uuid; 160 uuid_last.time.ll = (time + count - 1) & ((1LL << 60) - 1LL); 161 162 mtx_unlock(&uuid_mutex); 163 164 /* Set sequence and variant and deal with byte order. */ 165 uuid.seq = htobe16(uuid.seq | 0x8000); 166 167 for (n = 0; n < count; n++) { 168 /* Set time and version (=1). */ 169 uuid.time.x.low = (uint32_t)time; 170 uuid.time.x.mid = (uint16_t)(time >> 32); 171 uuid.time.x.hi = ((uint16_t)(time >> 48) & 0xfff) | (1 << 12); 172 store[n] = *(struct uuid *)&uuid; 173 time++; 174 } 175 176 return (store); 177} 178 179#ifndef _SYS_SYSPROTO_H_ 180struct uuidgen_args { 181 struct uuid *store; 182 int count; 183}; 184#endif 185int 186uuidgen(struct thread *td, struct uuidgen_args *uap) 187{ 188 struct uuid *store; 189 size_t count; 190 int error; 191 192 /* 193 * Limit the number of UUIDs that can be created at the same time 194 * to some arbitrary number. This isn't really necessary, but I 195 * like to have some sort of upper-bound that's less than 2G :-) 196 * XXX probably needs to be tunable. 197 */ 198 if (uap->count < 1 || uap->count > 2048) 199 return (EINVAL); 200 201 count = uap->count; 202 store = malloc(count * sizeof(struct uuid), M_TEMP, M_WAITOK); 203 kern_uuidgen(store, count); 204 error = copyout(store, uap->store, count * sizeof(struct uuid)); 205 free(store, M_TEMP); 206 return (error); 207} 208 209int 210snprintf_uuid(char *buf, size_t sz, struct uuid *uuid) 211{ 212 struct uuid_private *id; 213 int cnt; 214 215 id = (struct uuid_private *)uuid; 216 cnt = snprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x", 217 id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq), 218 be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2])); 219 return (cnt); 220} 221 222int 223printf_uuid(struct uuid *uuid) 224{ 225 char buf[38]; 226 227 snprintf_uuid(buf, sizeof(buf), uuid); 228 return (printf("%s", buf)); 229} 230 231int 232sbuf_printf_uuid(struct sbuf *sb, struct uuid *uuid) 233{ 234 char buf[38]; 235 236 snprintf_uuid(buf, sizeof(buf), uuid); 237 return (sbuf_printf(sb, "%s", buf)); 238} 239 240/* 241 * Encode/Decode UUID into byte-stream. 242 * http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt 243 * 244 * 0 1 2 3 245 * 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 1 246 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 247 * | time_low | 248 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 249 * | time_mid | time_hi_and_version | 250 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 251 * |clk_seq_hi_res | clk_seq_low | node (0-1) | 252 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 253 * | node (2-5) | 254 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 255 */ 256 257void 258le_uuid_enc(void *buf, struct uuid const *uuid) 259{ 260 u_char *p; 261 int i; 262 263 p = buf; 264 le32enc(p, uuid->time_low); 265 le16enc(p + 4, uuid->time_mid); 266 le16enc(p + 6, uuid->time_hi_and_version); 267 p[8] = uuid->clock_seq_hi_and_reserved; 268 p[9] = uuid->clock_seq_low; 269 for (i = 0; i < _UUID_NODE_LEN; i++) 270 p[10 + i] = uuid->node[i]; 271} 272 273void 274le_uuid_dec(void const *buf, struct uuid *uuid) 275{ 276 u_char const *p; 277 int i; 278 279 p = buf; 280 uuid->time_low = le32dec(p); 281 uuid->time_mid = le16dec(p + 4); 282 uuid->time_hi_and_version = le16dec(p + 6); 283 uuid->clock_seq_hi_and_reserved = p[8]; 284 uuid->clock_seq_low = p[9]; 285 for (i = 0; i < _UUID_NODE_LEN; i++) 286 uuid->node[i] = p[10 + i]; 287} 288 289void 290be_uuid_enc(void *buf, struct uuid const *uuid) 291{ 292 u_char *p; 293 int i; 294 295 p = buf; 296 be32enc(p, uuid->time_low); 297 be16enc(p + 4, uuid->time_mid); 298 be16enc(p + 6, uuid->time_hi_and_version); 299 p[8] = uuid->clock_seq_hi_and_reserved; 300 p[9] = uuid->clock_seq_low; 301 for (i = 0; i < _UUID_NODE_LEN; i++) 302 p[10 + i] = uuid->node[i]; 303} 304 305void 306be_uuid_dec(void const *buf, struct uuid *uuid) 307{ 308 u_char const *p; 309 int i; 310 311 p = buf; 312 uuid->time_low = be32dec(p); 313 uuid->time_mid = le16dec(p + 4); 314 uuid->time_hi_and_version = be16dec(p + 6); 315 uuid->clock_seq_hi_and_reserved = p[8]; 316 uuid->clock_seq_low = p[9]; 317 for (i = 0; i < _UUID_NODE_LEN; i++) 318 uuid->node[i] = p[10 + i]; 319} 320 321int 322parse_uuid(const char *str, struct uuid *uuid) 323{ 324 u_int c[11]; 325 int n; 326 327 /* An empty string represents a nil UUID. */ 328 if (*str == '\0') { 329 bzero(uuid, sizeof(*uuid)); 330 return (0); 331 } 332 333 /* The UUID string representation has a fixed length. */ 334 if (strlen(str) != 36) 335 return (EINVAL); 336 337 /* 338 * We only work with "new" UUIDs. New UUIDs have the form: 339 * 01234567-89ab-cdef-0123-456789abcdef 340 * The so called "old" UUIDs, which we don't support, have the form: 341 * 0123456789ab.cd.ef.01.23.45.67.89.ab 342 */ 343 if (str[8] != '-') 344 return (EINVAL); 345 346 n = sscanf(str, "%8x-%4x-%4x-%2x%2x-%2x%2x%2x%2x%2x%2x", c + 0, c + 1, 347 c + 2, c + 3, c + 4, c + 5, c + 6, c + 7, c + 8, c + 9, c + 10); 348 /* Make sure we have all conversions. */ 349 if (n != 11) 350 return (EINVAL); 351 352 /* Successful scan. Build the UUID. */ 353 uuid->time_low = c[0]; 354 uuid->time_mid = c[1]; 355 uuid->time_hi_and_version = c[2]; 356 uuid->clock_seq_hi_and_reserved = c[3]; 357 uuid->clock_seq_low = c[4]; 358 for (n = 0; n < 6; n++) 359 uuid->node[n] = c[n + 5]; 360 361 /* Check semantics... */ 362 return (((c[3] & 0x80) != 0x00 && /* variant 0? */ 363 (c[3] & 0xc0) != 0x80 && /* variant 1? */ 364 (c[3] & 0xe0) != 0xc0) ? EINVAL : 0); /* variant 2? */ 365} 366