sys/kern/kern_uuid.c

   1 /*      $NetBSD: kern_uuid.c,v 1.15 2008/07/02 14:47:34 matt Exp $      */
   2
   3 /*
   4  * Copyright (c) 2002 Marcel Moolenaar
   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  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * $FreeBSD: /repoman/r/ncvs/src/sys/kern/kern_uuid.c,v 1.7 2004/01/12 13:34:11 rse Exp $
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __KERNEL_RCSID(0, "$NetBSD: kern_uuid.c,v 1.15 2008/07/02 14:47:34 matt Exp $");
  33
  34 #include <sys/param.h>
  35 #include <sys/endian.h>
  36 #include <sys/kernel.h>
  37 #include <sys/mutex.h>
  38 #include <sys/socket.h>
  39 #include <sys/systm.h>
  40 #include <sys/uuid.h>
  41
  42 /* NetBSD */
  43 #include <sys/proc.h>
  44 #include <sys/mount.h>
  45 #include <sys/syscallargs.h>
  46 #include <sys/uio.h>
  47
  48 #include <net/if.h>
  49 #include <net/if_dl.h>
  50 #include <net/if_types.h>
  51
  52 /*
  53  * See also:
  54  *      http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
  55  *      http://www.opengroup.org/onlinepubs/009629399/apdxa.htm
  56  *
  57  * Note that the generator state is itself an UUID, but the time and clock
  58  * sequence fields are written in the native byte order.
  59  */
  60
  61 CTASSERT(sizeof(struct uuid) == 16);
  62
  63 /* We use an alternative, more convenient representation in the generator. */
  64 struct uuid_private {
  65         union {
  66                 uint64_t        ll;             /* internal. */
  67                 struct {
  68                         uint32_t        low;
  69                         uint16_t        mid;
  70                         uint16_t        hi;
  71                 } x;
  72         } time;
  73         uint16_t        seq;                    /* Big-endian. */
  74         uint16_t        node[UUID_NODE_LEN>>1];
  75 };
  76
  77 CTASSERT(sizeof(struct uuid_private) == 16);
  78
  79 static struct uuid_private uuid_last;
  80
  81 /* "UUID generator mutex lock" */
  82 static kmutex_t uuid_mutex;
  83
  84 void
  85 uuid_init(void)
  86 {
  87
  88         mutex_init(&uuid_mutex, MUTEX_DEFAULT, IPL_NONE);
  89 }
  90
  91 /*
  92  * Return the first MAC address we encounter or, if none was found,
  93  * construct a sufficiently random multicast address. We don't try
  94  * to return the same MAC address as previously returned. We always
  95  * generate a new multicast address if no MAC address exists in the
  96  * system.
  97  * It would be nice to know if 'ifnet' or any of its sub-structures
  98  * has been changed in any way. If not, we could simply skip the
  99  * scan and safely return the MAC address we returned before.
 100  */
 101 static void
 102 uuid_node(uint16_t *node)
 103 {
 104         struct ifnet *ifp;
 105         struct ifaddr *ifa;
 106         struct sockaddr_dl *sdl;
 107         int i, s;
 108
 109         s = splnet();
 110         KERNEL_LOCK(1, NULL);
 111         IFNET_FOREACH(ifp) {
 112                 /* Walk the address list */
 113                 IFADDR_FOREACH(ifa, ifp) {
 114                         sdl = (struct sockaddr_dl*)ifa->ifa_addr;
 115                         if (sdl != NULL && sdl->sdl_family == AF_LINK &&
 116                             sdl->sdl_type == IFT_ETHER) {
 117                                 /* Got a MAC address. */
 118                                 memcpy(node, CLLADDR(sdl), UUID_NODE_LEN);
 119                                 KERNEL_UNLOCK_ONE(NULL);
 120                                 splx(s);
 121                                 return;
 122                         }
 123                 }
 124         }
 125         KERNEL_UNLOCK_ONE(NULL);
 126         splx(s);
 127
 128         for (i = 0; i < (UUID_NODE_LEN>>1); i++)
 129                 node[i] = (uint16_t)arc4random();
 130         *((uint8_t*)node) |= 0x01;
 131 }
 132
 133 /*
 134  * Get the current time as a 60 bit count of 100-nanosecond intervals
 135  * since 00:00:00.00, October 15,1582. We apply a magic offset to convert
 136  * the Unix time since 00:00:00.00, January 1, 1970 to the date of the
 137  * Gregorian reform to the Christian calendar.
 138  */
 139 /*
 140  * At present, NetBSD has no timespec source, only timeval sources.  So,
 141  * we use timeval.
 142  */
 143 static uint64_t
 144 uuid_time(void)
 145 {
 146         struct timeval tv;
 147         uint64_t xtime = 0x01B21DD213814000LL;
 148
 149         microtime(&tv);
 150         xtime += (uint64_t)tv.tv_sec * 10000000LL;
 151         xtime += (uint64_t)(10 * tv.tv_usec);
 152         return (xtime & ((1LL << 60) - 1LL));
 153 }
 154
 155 /*
 156  * Internal routine to actually generate the UUID.
 157  */
 158 static void
 159 uuid_generate(struct uuid_private *uuid, uint64_t *timep, int count)
 160 {
 161         uint64_t xtime;
 162
 163         mutex_enter(&uuid_mutex);
 164
 165         uuid_node(uuid->node);
 166         xtime = uuid_time();
 167         *timep = xtime;
 168
 169         if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid->node[0] ||
 170             uuid_last.node[1] != uuid->node[1] ||
 171             uuid_last.node[2] != uuid->node[2])
 172                 uuid->seq = (uint16_t)arc4random() & 0x3fff;
 173         else if (uuid_last.time.ll >= xtime)
 174                 uuid->seq = (uuid_last.seq + 1) & 0x3fff;
 175         else
 176                 uuid->seq = uuid_last.seq;
 177
 178         uuid_last = *uuid;
 179         uuid_last.time.ll = (xtime + count - 1) & ((1LL << 60) - 1LL);
 180
 181         mutex_exit(&uuid_mutex);
 182 }
 183
 184 static int
 185 kern_uuidgen(struct uuid *store, int count, bool to_user)
 186 {
 187         struct uuid_private uuid;
 188         uint64_t xtime;
 189         int error = 0, i;
 190
 191         KASSERT(count >= 1);
 192
 193         /* Generate the base UUID. */
 194         uuid_generate(&uuid, &xtime, count);
 195
 196         /* Set sequence and variant and deal with byte order. */
 197         uuid.seq = htobe16(uuid.seq | 0x8000);
 198
 199         for (i = 0; i < count; xtime++, i++) {
 200                 /* Set time and version (=1) and deal with byte order. */
 201                 uuid.time.x.low = (uint32_t)xtime;
 202                 uuid.time.x.mid = (uint16_t)(xtime >> 32);
 203                 uuid.time.x.hi = ((uint16_t)(xtime >> 48) & 0xfff) | (1 << 12);
 204                 if (to_user) {
 205                         error = copyout(&uuid, store + i, sizeof(uuid));
 206                         if (error != 0)
 207                                 break;
 208                 } else {
 209                         memcpy(store + i, &uuid, sizeof(uuid));
 210                 }
 211         }
 212
 213         return error;
 214 }
 215
 216 int
 217 sys_uuidgen(struct lwp *l, const struct sys_uuidgen_args *uap, register_t *retval)
 218 {
 219         /*
 220          * Limit the number of UUIDs that can be created at the same time
 221          * to some arbitrary number. This isn't really necessary, but I
 222          * like to have some sort of upper-bound that's less than 2G :-)
 223          * XXX needs to be tunable.
 224          */
 225         if (SCARG(uap,count) < 1 || SCARG(uap,count) > 2048)
 226                 return (EINVAL);
 227
 228         return kern_uuidgen(SCARG(uap, store), SCARG(uap,count), true);
 229 }
 230
 231 int
 232 uuidgen(struct uuid *store, int count)
 233 {
 234         return kern_uuidgen(store,count, false);
 235 }
 236
 237 int
 238 uuid_snprintf(char *buf, size_t sz, const struct uuid *uuid)
 239 {
 240         const struct uuid_private *id;
 241         int cnt;
 242
 243         id = (const struct uuid_private *)uuid;
 244         cnt = snprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x",
 245             id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq),
 246             be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2]));
 247         return (cnt);
 248 }
 249
 250 int
 251 uuid_printf(const struct uuid *uuid)
 252 {
 253         char buf[UUID_STR_LEN];
 254
 255         (void) uuid_snprintf(buf, sizeof(buf), uuid);
 256         printf("%s", buf);
 257         return (0);
 258 }
 259
 260 /*
 261  * Encode/Decode UUID into octet-stream.
 262  *   http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
 263  *
 264  * 0                   1                   2                   3
 265  *   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
 266  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 267  *  |                          time_low                             |
 268  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 269  *  |       time_mid                |         time_hi_and_version   |
 270  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 271  *  |clk_seq_hi_res |  clk_seq_low  |         node (0-1)            |
 272  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 273  *  |                         node (2-5)                            |
 274  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 275  */
 276
 277 void
 278 uuid_enc_le(void *buf, const struct uuid *uuid)
 279 {
 280         uint8_t *p = buf;
 281         int i;
 282
 283         le32enc(p, uuid->time_low);
 284         le16enc(p + 4, uuid->time_mid);
 285         le16enc(p + 6, uuid->time_hi_and_version);
 286         p[8] = uuid->clock_seq_hi_and_reserved;
 287         p[9] = uuid->clock_seq_low;
 288         for (i = 0; i < _UUID_NODE_LEN; i++)
 289                 p[10 + i] = uuid->node[i];
 290 }
 291
 292 void
 293 uuid_dec_le(void const *buf, struct uuid *uuid)
 294 {
 295         const uint8_t *p = buf;
 296         int i;
 297
 298         uuid->time_low = le32dec(p);
 299         uuid->time_mid = le16dec(p + 4);
 300         uuid->time_hi_and_version = le16dec(p + 6);
 301         uuid->clock_seq_hi_and_reserved = p[8];
 302         uuid->clock_seq_low = p[9];
 303         for (i = 0; i < _UUID_NODE_LEN; i++)
 304                 uuid->node[i] = p[10 + i];
 305 }
 306
 307 void
 308 uuid_enc_be(void *buf, const struct uuid *uuid)
 309 {
 310         uint8_t *p = buf;
 311         int i;
 312
 313         be32enc(p, uuid->time_low);
 314         be16enc(p + 4, uuid->time_mid);
 315         be16enc(p + 6, uuid->time_hi_and_version);
 316         p[8] = uuid->clock_seq_hi_and_reserved;
 317         p[9] = uuid->clock_seq_low;
 318         for (i = 0; i < _UUID_NODE_LEN; i++)
 319                 p[10 + i] = uuid->node[i];
 320 }
 321
 322 void
 323 uuid_dec_be(void const *buf, struct uuid *uuid)
 324 {
 325         const uint8_t *p = buf;
 326         int i;
 327
 328         uuid->time_low = be32dec(p);
 329         uuid->time_mid = be16dec(p + 4);
 330         uuid->time_hi_and_version = be16dec(p + 6);
 331         uuid->clock_seq_hi_and_reserved = p[8];
 332         uuid->clock_seq_low = p[9];
 333         for (i = 0; i < _UUID_NODE_LEN; i++)
 334                 uuid->node[i] = p[10 + i];
 335 }