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