diff options
Diffstat (limited to 'src/duid.c')
| -rw-r--r-- | src/duid.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/src/duid.c b/src/duid.c new file mode 100644 index 000000000000..be626f510082 --- /dev/null +++ b/src/duid.c @@ -0,0 +1,236 @@ +/* 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; +} |