external/bsd/dhcpcd/dist/duid.c

   1 /*
   2  * dhcpcd - DHCP client daemon
   3  * Copyright (c) 2006-2008 Roy Marples <roy@marples.name>
   4  * All rights reserved
   5
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   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 AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #define THIRTY_YEARS_IN_SECONDS    946707779
  29
  30 #include <errno.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <time.h>
  35 #include <unistd.h>
  36
  37 #include "common.h"
  38 #include "duid.h"
  39 #include "net.h"
  40
  41 size_t
  42 get_duid(unsigned char *duid, const struct interface *iface)
  43 {
  44         FILE *f;
  45         uint16_t type = 0;
  46         uint16_t hw = 0;
  47         uint32_t ul;
  48         time_t t;
  49         int x = 0;
  50         unsigned char *p = duid;
  51         size_t len = 0;
  52         char *line;
  53
  54         /* If we already have a DUID then use it as it's never supposed
  55          * to change once we have one even if the interfaces do */
  56         if ((f = fopen(DUID, "r"))) {
  57                 while ((line = get_line(f))) {
  58                         len = hwaddr_aton(NULL, line);
  59                         if (len && len <= DUID_LEN) {
  60                                 hwaddr_aton(duid, line);
  61                                 break;
  62                         }
  63                         len = 0;
  64                 }
  65                 fclose(f);
  66                 if (len)
  67                         return len;
  68         } else {
  69                 if (errno != ENOENT)
  70                         return 0;
  71         }
  72
  73         /* No file? OK, lets make one based on our interface */
  74         if (!(f = fopen(DUID, "w")))
  75                 return 0;
  76         type = htons(1); /* DUI-D-LLT */
  77         memcpy(p, &type, 2);
  78         p += 2;
  79         hw = htons(iface->family);
  80         memcpy(p, &hw, 2);
  81         p += 2;
  82         /* time returns seconds from jan 1 1970, but DUID-LLT is
  83          * seconds from jan 1 2000 modulo 2^32 */
  84         t = time(NULL) - THIRTY_YEARS_IN_SECONDS;
  85         ul = htonl(t & 0xffffffff);
  86         memcpy(p, &ul, 4);
  87         p += 4;
  88         /* Finally, add the MAC address of the interface */
  89         memcpy(p, iface->hwaddr, iface->hwlen);
  90         p += iface->hwlen;
  91         len = p - duid;
  92         x = fprintf(f, "%s\n", hwaddr_ntoa(duid, len));
  93         fclose(f);
  94         /* Failed to write the duid? scrub it, we cannot use it */
  95         if (x < 1) {
  96                 len = 0;
  97                 unlink(DUID);
  98         }
  99         return len;
 100 }