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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* dhcpcd - DHCP client daemon
* Copyright (c) 2006-2021 Roy Marples <roy@marples.name>
* All rights reserved
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#define UUID_LEN 36
#define DUID_TIME_EPOCH 946684800
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/types.h>
#ifdef BSD
# include <sys/sysctl.h>
#endif
#include <arpa/inet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "common.h"
#include "dhcpcd.h"
#include "duid.h"
#include "logerr.h"
static size_t
duid_machineuuid(char *uuid, size_t uuid_len)
{
int r;
size_t len = uuid_len;
#if defined(HW_UUID) /* OpenBSD */
int mib[] = { CTL_HW, HW_UUID };
r = sysctl(mib, sizeof(mib)/sizeof(mib[0]), uuid, &len, NULL, 0);
#elif defined(KERN_HOSTUUID) /* FreeBSD */
int mib[] = { CTL_KERN, KERN_HOSTUUID };
r = sysctl(mib, sizeof(mib)/sizeof(mib[0]), uuid, &len, NULL, 0);
#elif defined(__NetBSD__)
r = sysctlbyname("machdep.dmi.system-uuid", uuid, &len, NULL, 0);
#elif defined(__linux__)
FILE *fp;
fp = fopen("/sys/class/dmi/id/product_uuid", "r");
if (fp == NULL)
return 0;
if (fgets(uuid, (int)uuid_len, fp) == NULL) {
fclose(fp);
return 0;
}
len = strlen(uuid) + 1;
fclose(fp);
r = len == 1 ? -1 : 0;
#else
UNUSED(uuid);
r = -1;
errno = ENOSYS;
#endif
if (r == -1)
return 0;
return len;
}
static size_t
duid_make_uuid(uint8_t *d)
{
uint16_t type = htons(DUID_UUID);
char uuid[UUID_LEN + 1];
size_t l;
if (duid_machineuuid(uuid, sizeof(uuid)) != sizeof(uuid))
return 0;
/* All zeros UUID is not valid */
if (strcmp("00000000-0000-0000-0000-000000000000", uuid) == 0)
return 0;
memcpy(d, &type, sizeof(type));
l = sizeof(type);
d += sizeof(type);
l += hwaddr_aton(d, uuid);
return l;
}
size_t
duid_make(void *d, const struct interface *ifp, uint16_t type)
{
uint8_t *p;
uint16_t u16;
time_t t;
uint32_t u32;
if (ifp->hwlen == 0)
return 0;
p = d;
u16 = htons(type);
memcpy(p, &u16, sizeof(u16));
p += sizeof(u16);
u16 = htons(ifp->hwtype);
memcpy(p, &u16, sizeof(u16));
p += sizeof(u16);
if (type == DUID_LLT) {
/* time returns seconds from jan 1 1970, but DUID-LLT is
* seconds from jan 1 2000 modulo 2^32 */
t = time(NULL) - DUID_TIME_EPOCH;
u32 = htonl((uint32_t)t & 0xffffffff);
memcpy(p, &u32, sizeof(u32));
p += sizeof(u32);
}
/* Finally, add the MAC address of the interface */
memcpy(p, ifp->hwaddr, ifp->hwlen);
p += ifp->hwlen;
return (size_t)(p - (uint8_t *)d);
}
#define DUID_STRLEN DUID_LEN * 3
static size_t
duid_get(struct dhcpcd_ctx *ctx, const struct interface *ifp)
{
uint8_t *data;
size_t len, slen;
char line[DUID_STRLEN];
const struct interface *ifp2;
/* 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 ((len = dhcp_read_hwaddr_aton(ctx, &data, DUID)) != 0) {
if (len <= DUID_LEN) {
ctx->duid = data;
return len;
}
logerrx("DUID too big (max %u): %s", DUID_LEN, DUID);
/* Keep the buffer, will assign below. */
} else {
if (errno != ENOENT)
logerr("%s", DUID);
if ((data = malloc(DUID_LEN)) == NULL) {
logerr(__func__);
return 0;
}
}
/* No file? OK, lets make one based the machines UUID */
if (ifp == NULL) {
if (ctx->duid_type != DUID_DEFAULT &&
ctx->duid_type != DUID_UUID)
len = 0;
else
len = duid_make_uuid(data);
if (len == 0)
free(data);
else
ctx->duid = data;
return len;
}
/* Regardless of what happens we will create a DUID to use. */
ctx->duid = data;
/* No UUID? OK, lets make one based on our interface */
if (ifp->hwlen == 0) {
logwarnx("%s: does not have hardware address", ifp->name);
TAILQ_FOREACH(ifp2, ifp->ctx->ifaces, next) {
if (ifp2->hwlen != 0)
break;
}
if (ifp2) {
ifp = ifp2;
logwarnx("picked interface %s to generate a DUID",
ifp->name);
} else {
if (ctx->duid_type != DUID_LL)
logwarnx("no interfaces have a fixed hardware "
"address");
return duid_make(data, ifp, DUID_LL);
}
}
len = duid_make(data, ifp,
ctx->duid_type == DUID_LL ? DUID_LL : DUID_LLT);
hwaddr_ntoa(data, len, line, sizeof(line));
slen = strlen(line);
if (slen < sizeof(line) - 2) {
line[slen++] = '\n';
line[slen] = '\0';
}
if (dhcp_writefile(ctx, DUID, 0640, line, slen) == -1) {
logerr("%s: cannot write duid", __func__);
if (ctx->duid_type != DUID_LL)
return duid_make(data, ifp, DUID_LL);
}
return len;
}
size_t
duid_init(struct dhcpcd_ctx *ctx, const struct interface *ifp)
{
if (ctx->duid == NULL)
ctx->duid_len = duid_get(ctx, ifp);
return ctx->duid_len;
}
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