kern_uuid.c

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

FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_uuid.c
