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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
Copyright © 2015 Tom Gundersen <teg@jklmen>
***/
#include "libudev.h"
#include "sd-id128.h"
#include "dhcp-identifier.h"
#include "dhcp6-protocol.h"
#include "network-internal.h"
#include "siphash24.h"
#include "sparse-endian.h"
#include "udev-util.h"
#include "virt.h"
#define SYSTEMD_PEN 43793
#define HASH_KEY SD_ID128_MAKE(80,11,8c,c2,fe,4a,03,ee,3e,d6,0c,6f,36,39,14,09)
int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len) {
struct duid d;
assert_cc(sizeof(d.raw) >= MAX_DUID_LEN);
if (duid_len > MAX_DUID_LEN)
return -EINVAL;
switch (duid_type) {
case DUID_TYPE_LLT:
if (duid_len <= sizeof(d.llt))
return -EINVAL;
break;
case DUID_TYPE_EN:
if (duid_len != sizeof(d.en))
return -EINVAL;
break;
case DUID_TYPE_LL:
if (duid_len <= sizeof(d.ll))
return -EINVAL;
break;
case DUID_TYPE_UUID:
if (duid_len != sizeof(d.uuid))
return -EINVAL;
break;
default:
/* accept unknown type in order to be forward compatible */
break;
}
return 0;
}
int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len) {
sd_id128_t machine_id;
uint64_t hash;
int r;
assert(duid);
assert(len);
r = sd_id128_get_machine(&machine_id);
if (r < 0)
return r;
unaligned_write_be16(&duid->type, DUID_TYPE_EN);
unaligned_write_be32(&duid->en.pen, SYSTEMD_PEN);
*len = sizeof(duid->type) + sizeof(duid->en);
/* a bit of snake-oil perhaps, but no need to expose the machine-id
directly; duid->en.id might not be aligned, so we need to copy */
hash = htole64(siphash24(&machine_id, sizeof(machine_id), HASH_KEY.bytes));
memcpy(duid->en.id, &hash, sizeof(duid->en.id));
return 0;
}
int dhcp_identifier_set_iaid(int ifindex, uint8_t *mac, size_t mac_len, void *_id) {
/* name is a pointer to memory in the udev_device struct, so must
have the same scope */
_cleanup_(udev_device_unrefp) struct udev_device *device = NULL;
const char *name = NULL;
uint64_t id;
if (detect_container() <= 0) {
/* not in a container, udev will be around */
_cleanup_(udev_unrefp) struct udev *udev;
char ifindex_str[2 + DECIMAL_STR_MAX(int)];
udev = udev_new();
if (!udev)
return -ENOMEM;
sprintf(ifindex_str, "n%d", ifindex);
device = udev_device_new_from_device_id(udev, ifindex_str);
if (device) {
if (udev_device_get_is_initialized(device) <= 0)
/* not yet ready */
return -EBUSY;
name = net_get_name(device);
}
}
if (name)
id = siphash24(name, strlen(name), HASH_KEY.bytes);
else
/* fall back to MAC address if no predictable name available */
id = siphash24(mac, mac_len, HASH_KEY.bytes);
id = htole64(id);
/* fold into 32 bits */
unaligned_write_be32(_id, (id & 0xffffffff) ^ (id >> 32));
return 0;
}
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