dhcpcd/duid.c
2007-05-10 16:08:49 +00:00

121 lines
2.9 KiB
C

/*
* dhcpcd - DHCP client daemon -
* Copyright 2006-2007 Roy Marples <uberlord@gentoo.org>
*
* dhcpcd is an RFC2131 compliant DHCP client daemon.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "config.h"
#include "common.h"
#include "duid.h"
#include "logger.h"
#ifdef ENABLE_DUID
#define DUID_LEN 130
#define THIRTY_YEARS_IN_SECONDS 946707779
void get_duid (interface_t *iface)
{
FILE *fp;
uint16_t type = 0;
uint16_t hw = 0;
uint32_t ul;
time_t t;
unsigned char *p = iface->duid;
int x = 0;
if (! iface)
return;
/* Remove any existing */
iface->duid[0] = '\0';
iface->duid_length = 0;
/* If we already have a DUID then use it as it's never supposed
* to change once we have one even if the interfaces do */
if ((fp = fopen (DUIDFILE, "r"))) {
char *fduid;
char *fdp;
fduid = fdp = xmalloc ((sizeof (char *) * DUID_LEN * 2) + 1);
if (fscanf (fp, "%260s", fduid) == 1) {
char c[3];
c[2] = '\0';
while (*fdp) {
c[0] = *fdp++;
c[1] = *fdp++;
*p++ = (char) strtol (c, NULL, 16);
}
}
free (fduid);
iface->duid_length = p - iface->duid;
fclose (fp);
return;
}
if (errno != ENOENT) {
logger (LOG_ERR, "fopen `%s': %s", DUIDFILE, strerror (errno));
return;
}
/* No file? OK, lets make one based on our interface */
type = htons (1); /* DUI-D-LLT */
memcpy (p, &type, 2);
p += 2;
hw = htons (iface->family);
memcpy (p, &hw, 2);
p += 2;
/* time returns seconds from jan 1 1970, but DUID-LLT is
* seconds from jan 1 2000 modulo 2^32 */
t = time (NULL) - THIRTY_YEARS_IN_SECONDS;
ul = htonl (t & 0xffffffff);
memcpy (p, &ul, 4);
p += 4;
/* Finally, add the MAC address of the interface */
memcpy (p, iface->hwaddr, iface->hwlen);
p += iface->hwlen;
iface->duid_length = p - iface->duid;
if (! (fp = fopen (DUIDFILE, "w")))
logger (LOG_ERR, "fopen `%s': %s", DUIDFILE, strerror (errno));
else {
int i;
for (i = 0; i < iface->duid_length; i++)
x += fprintf (fp, "%.2X", iface->duid[i]);
fprintf (fp, "\n");
fclose (fp);
}
/* Failed to write the duid? scrub it, we cannot use it */
if (x < 1) {
memset (iface->duid, 0, sizeof (iface->duid));
iface->duid_length = 0;
}
}
#endif