uuid/uuidsrc/gen_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 #define get_random_bytes(a,b)   arc4random_buf((a),(b))
  76
  77 /*
  78  * Get the ethernet hardware address, if we can find it...
  79  */
  80 static int get_node_id(unsigned char *node_id)
  81 {
  82 #ifdef HAVE_NET_IF_H
  83         int             sd;
  84         struct ifreq    ifr, *ifrp;
  85         struct ifconf   ifc;
  86         char buf[1024];
  87         int             n, i;
  88         unsigned char   *a;
  89 #ifdef AF_LINK
  90         struct sockaddr_dl *sdlp;
  91 #endif
  92
  93 /*
  94  * BSD 4.4 defines the size of an ifreq to be
  95  * max(sizeof(ifreq), sizeof(ifreq.ifr_name)+ifreq.ifr_addr.sa_len
  96  * However, under earlier systems, sa_len isn't present, so the size is
  97  * just sizeof(struct ifreq)
  98  */
  99 #ifdef HAVE_SA_LEN
 100 #ifndef max
 101 #define max(a,b) ((a) > (b) ? (a) : (b))
 102 #endif
 103 #define ifreq_size(i) max(sizeof(struct ifreq),\
 104      sizeof((i).ifr_name)+(i).ifr_addr.sa_len)
 105 #else
 106 #define ifreq_size(i) sizeof(struct ifreq)
 107 #endif /* HAVE_SA_LEN*/
 108
 109         sd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
 110         if (sd < 0) {
 111                 return -1;
 112         }
 113         memset(buf, 0, sizeof(buf));
 114         ifc.ifc_len = sizeof(buf);
 115         ifc.ifc_buf = buf;
 116         if (ioctl (sd, SIOCGIFCONF, (char *)&ifc) < 0) {
 117                 close(sd);
 118                 return -1;
 119         }
 120         n = ifc.ifc_len;
 121         for (i = 0; i < n; i+= ifreq_size(*ifrp) ) {
 122                 ifrp = (struct ifreq *)((char *) ifc.ifc_buf+i);
 123                 strncpy(ifr.ifr_name, ifrp->ifr_name, IFNAMSIZ);
 124 #ifdef SIOCGIFHWADDR
 125                 if (ioctl(sd, SIOCGIFHWADDR, &ifr) < 0)
 126                         continue;
 127                 a = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
 128 #else
 129 #ifdef SIOCGENADDR
 130                 if (ioctl(sd, SIOCGENADDR, &ifr) < 0)
 131                         continue;
 132                 a = (unsigned char *) ifr.ifr_enaddr;
 133 #else
 134 #ifdef AF_LINK
 135                 sdlp = (struct sockaddr_dl *) &ifrp->ifr_addr;
 136                 if ((sdlp->sdl_family != AF_LINK) || (sdlp->sdl_alen != 6))
 137                         continue;
 138                 a = (unsigned char *) &sdlp->sdl_data[sdlp->sdl_nlen];
 139 #else
 140                 /*
 141                  * XXX we don't have a way of getting the hardware
 142                  * address
 143                  */
 144                 close(sd);
 145                 return 0;
 146 #endif /* AF_LINK */
 147 #endif /* SIOCGENADDR */
 148 #endif /* SIOCGIFHWADDR */
 149                 /*
 150                  * Skip interfaces that return either 00:00:00:00:00:00 or
 151                  * 02:00:00:00:00:00.
 152                  */
 153                 if ((!a[0] || a[0] == 0x02) && !a[1] && !a[2] && !a[3] && !a[4] && !a[5])
 154                         continue;
 155                 if (node_id) {
 156                         memcpy(node_id, a, 6);
 157                         close(sd);
 158                         return 1;
 159                 }
 160         }
 161         close(sd);
 162 #endif
 163         return 0;
 164 }
 165
 166 /* Assume that the gettimeofday() has microsecond granularity */
 167 #define MAX_ADJUSTMENT 10
 168
 169 static int get_clock(uint32_t *clock_high, uint32_t *clock_low, uint16_t *ret_clock_seq)
 170 {
 171         static int                      adjustment = 0;
 172         static struct timeval           last = {0, 0};
 173         static uint16_t                 clock_seq;
 174         struct timeval                  tv;
 175         unsigned long long              clock_reg;
 176
 177 try_again:
 178         gettimeofday(&tv, 0);
 179         if ((last.tv_sec == 0) && (last.tv_usec == 0)) {
 180                 get_random_bytes(&clock_seq, sizeof(clock_seq));
 181                 clock_seq &= 0x3FFF;
 182                 last = tv;
 183                 last.tv_sec--;
 184         }
 185         if ((tv.tv_sec < last.tv_sec) ||
 186             ((tv.tv_sec == last.tv_sec) &&
 187              (tv.tv_usec < last.tv_usec))) {
 188                 clock_seq = (clock_seq+1) & 0x3FFF;
 189                 adjustment = 0;
 190                 last = tv;
 191         } else if ((tv.tv_sec == last.tv_sec) &&
 192             (tv.tv_usec == last.tv_usec)) {
 193                 if (adjustment >= MAX_ADJUSTMENT)
 194                         goto try_again;
 195                 adjustment++;
 196         } else {
 197                 adjustment = 0;
 198                 last = tv;
 199         }
 200
 201         clock_reg = tv.tv_usec*10 + adjustment;
 202         clock_reg += ((unsigned long long) tv.tv_sec)*10000000;
 203         clock_reg += (((unsigned long long) 0x01B21DD2) << 32) + 0x13814000;
 204
 205         *clock_high = clock_reg >> 32;
 206         *clock_low = clock_reg;
 207         *ret_clock_seq = clock_seq;
 208         return 0;
 209 }
 210
 211 void uuid_generate_time(uuid_t out)
 212 {
 213         static unsigned char node_id[6];
 214         static int has_init = 0;
 215         struct uuid uu;
 216         uint32_t        clock_mid;
 217
 218         if (!has_init) {
 219                 if (get_node_id(node_id) <= 0) {
 220                         get_random_bytes(node_id, 6);
 221                         /*
 222                          * Set multicast bit, to prevent conflicts
 223                          * with IEEE 802 addresses obtained from
 224                          * network cards
 225                          */
 226                         node_id[0] |= 0x01;
 227                 }
 228                 has_init = 1;
 229         }
 230         get_clock(&clock_mid, &uu.time_low, &uu.clock_seq);
 231         uu.clock_seq |= 0x8000;
 232         uu.time_mid = (uint16_t) clock_mid;
 233         uu.time_hi_and_version = ((clock_mid >> 16) & 0x0FFF) | 0x1000;
 234         memcpy(uu.node, node_id, 6);
 235         uuid_pack(&uu, out);
 236 }
 237
 238 void uuid_generate_random(uuid_t out)
 239 {
 240         uuid_t  buf;
 241         struct uuid uu;
 242
 243         get_random_bytes(buf, sizeof(buf));
 244         uuid_unpack(buf, &uu);
 245
 246         uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
 247         uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF) | 0x4000;
 248         uuid_pack(&uu, out);
 249 }
 250
 251 /*
 252  * This is the generic front-end
 253  */
 254 void uuid_generate(uuid_t out)
 255 {
 256         uuid_generate_random(out);
 257 }