uuid/gen_uuid-uuid.c

   1 /*
   2  * gen_uuid.c --- generate a DCE-compatible uuid
   3  *
   4  * Copyright (C) 1996, 1997, 1998, 1999 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   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  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, and the entire permission notice in its entirety,
  12  *    including the disclaimer of warranties.
  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  * 3. The name of the author may not be used to endorse or promote
  17  *    products derived from this software without specific prior
  18  *    written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  21  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
  23  * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
  24  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  26  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  27  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  28  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
  30  * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
  31  * DAMAGE.
  32  * %End-Header%
  33  */
  34
  35 /*
  36  * Force inclusion of SVID stuff since we need it if we're compiling in
  37  * gcc-wall wall mode
  38  */
  39 #define _SVID_SOURCE
  40
  41 #ifdef HAVE_UNISTD_H
  42 #include <unistd.h>
  43 #endif
  44 #ifdef HAVE_STDLIB_H
  45 #include <stdlib.h>
  46 #endif
  47 #include <string.h>
  48 #include <fcntl.h>
  49 #include <errno.h>
  50 #include <sys/types.h>
  51 #include <sys/time.h>
  52 #include <sys/stat.h>
  53 #include <sys/file.h>
  54 #ifdef HAVE_SYS_IOCTL_H
  55 #include <sys/ioctl.h>
  56 #endif
  57 #ifdef HAVE_SYS_SOCKET_H
  58 #include <sys/socket.h>
  59 #endif
  60 #ifdef HAVE_SYS_SOCKIO_H
  61 #include <sys/sockio.h>
  62 #endif
  63 #ifdef HAVE_NET_IF_H
  64 #include <net/if.h>
  65 #endif
  66 #ifdef HAVE_NETINET_IN_H
  67 #include <netinet/in.h>
  68 #endif
  69 #ifdef HAVE_NET_IF_DL_H
  70 #include <net/if_dl.h>
  71 #endif
  72
  73 #include "uuidP.h"
  74
  75 /*
  76  * Generate a series of random bytes, using arc4random
  77  */
  78 static void get_random_bytes(void *buf, int nbytes)
  79 {
  80         unsigned char *cp = (unsigned char *) buf;
  81         u_int32_t u;
  82         int n = nbytes / sizeof(u);
  83
  84         while (n-- > 0) {
  85                 u = arc4random();
  86                 memcpy(cp, &u, sizeof(u));
  87                 cp += sizeof(u);
  88         }
  89         if ((n = nbytes % sizeof(u)) > 0) {
  90                 u = arc4random();
  91                 memcpy(cp, &u, n);
  92         }
  93         return;
  94 }
  95
  96 /*
  97  * Get the ethernet hardware address, if we can find it...
  98  */
  99 static int get_node_id(unsigned char *node_id)
 100 {
 101 #ifdef HAVE_NET_IF_H
 102         int             sd;
 103         struct ifreq    ifr, *ifrp;
 104         struct ifconf   ifc;
 105         char buf[1024];
 106         int             n, i;
 107         unsigned char   *a;
 108 #ifdef AF_LINK
 109         struct sockaddr_dl *sdlp;
 110 #endif
 111
 112 /*
 113  * BSD 4.4 defines the size of an ifreq to be
 114  * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
 115  * However, under earlier systems, sa_len isn't present, so the size is
 116  * just sizeof(struct ifreq)
 117  */
 118 #ifdef HAVE_SA_LEN
 119 #ifndef max
 120 #define max(a,b) ((a) > (b) ? (a) : (b))
 121 #endif
 122 #define ifreq_size(i) max(sizeof(struct ifreq),\
 123      sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
 124 #else
 125 #define ifreq_size(i) sizeof(struct ifreq)
 126 #endif /* HAVE_SA_LEN*/
 127
 128         sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
 129         if (sd < 0) {
 130                 return -1;
 131         }
 132         memset(buf, 0, sizeof(buf));
 133         ifc.ifc_len = sizeof(buf);
 134         ifc.ifc_buf = buf;
 135         if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
 136                 close(sd);
 137                 return -1;
 138         }
 139         n = ifc.ifc_len;
 140         for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
 141                 ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
 142                 strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
 143 #ifdef SIOCGIFHWADDR
 144                 if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
 145                         continue;
 146                 a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
 147 #else
 148 #ifdef SIOCGENADDR
 149                 if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
 150                         continue;
 151                 a = (unsigned char *) ifr.ifr_enaddr;
 152 #else
 153 #ifdef AF_LINK
 154                 sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
 155                 if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
 156                         continue;
 157                 a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
 158 #else
 159                 /*
 160                  * XXX we don't have a way of getting the hardware
 161                  * address
 162                  */
 163                 close(sd);
 164                 return 0;
 165 #endif /* AF_LINK */
 166 #endif /* SIOCGENADDR */
 167 #endif /* SIOCGIFHWADDR */
 168                 if (!a[0] && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
 169                         continue;
 170                 if (node_id) {
 171                         memcpy(node_id, a, 6);
 172                         close(sd);
 173                         return 1;
 174                 }
 175         }
 176         close(sd);
 177 #endif
 178         return 0;
 179 }
 180
 181 /* Assume that the gettimeofday() has microsecond granularity */
 182 #define MAX_ADJUSTMENT 10
 183
 184 static int get_clock(uint32_t *clock_high, uint32_t *clock_low, uint16_t *ret_clock_seq)
 185 {
 186         static int                      adjustment = 0;
 187         static struct timeval           last = {0, 0};
 188         static uint16_t                 clock_seq;
 189         struct timeval                  tv;
 190         unsigned long long              clock_reg;
 191
 192 try_again:
 193         gettimeofday(&tv, 0);
 194         if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
 195                 get_random_bytes(&clock_seq, sizeof(clock_seq));
 196                 clock_seq &= 0x3FFF;
 197                 last = tv;
 198                 last.tv_sec--;
 199         }
 200         if ((tv.tv_sec < last.tv_sec) ||
 201             ((tv.tv_sec == last.tv_sec) &&
 202              (tv.tv_usec < last.tv_usec))) {
 203                 clock_seq = (clock_seq+1) & 0x3FFF;
 204                 adjustment = 0;
 205                 last = tv;
 206         } else if ((tv.tv_sec == last.tv_sec) &&
 207             (tv.tv_usec == last.tv_usec)) {
 208                 if (adjustment >= MAX_ADJUSTMENT)
 209                         goto try_again;
 210                 adjustment++;
 211         } else {
 212                 adjustment = 0;
 213                 last = tv;
 214         }
 215
 216         clock_reg = tv.tv_usec*10 + adjustment;
 217         clock_reg += ((unsigned long long) tv.tv_sec)*10000000;
 218         clock_reg += (((unsigned long long) 0x01B21DD2) << 32) + 0x13814000;
 219
 220         *clock_high = clock_reg >> 32;
 221         *clock_low = clock_reg;
 222         *ret_clock_seq = clock_seq;
 223         return 0;
 224 }
 225
 226 void uuid_generate_time(uuid_t out)
 227 {
 228         static unsigned char node_id[6];
 229         static int has_init = 0;
 230         struct uuid uu;
 231         uint32_t        clock_mid;
 232
 233         if (!has_init) {
 234                 if (get_node_id(node_id) <= 0) {
 235                         get_random_bytes(node_id, 6);
 236                         /*
 237                          * Set multicast bit, to prevent conflicts
 238                          * with IEEE 802 addresses obtained from
 239                          * network cards
 240                          */
 241                         node_id[0] |= 0x01;
 242                 }
 243                 has_init = 1;
 244         }
 245         get_clock(&clock_mid, &uu.time_low, &uu.clock_seq);
 246         uu.clock_seq |= 0x8000;
 247         uu.time_mid = (uint16_t) clock_mid;
 248         uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
 249         memcpy(uu.node, node_id, 6);
 250         uuid_pack(&uu, out);
 251 }
 252
 253 void uuid_generate_random(uuid_t out)
 254 {
 255         uuid_t  buf;
 256         struct uuid uu;
 257
 258         get_random_bytes(buf, sizeof(buf));
 259         uuid_unpack(buf, &uu);
 260
 261         uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
 262         uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | 0x4000;
 263         uuid_pack(&uu, out);
 264 }
 265
 266 /*
 267  * This is the generic front-end
 268  */
 269 void uuid_generate(uuid_t out)
 270 {
 271         uuid_generate_random(out);
 272 }