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/***
This file is part of systemd.
Copyright (C) 2015 Tom Gundersen <teg@jklmen>
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#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_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, DHCP_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_unref_ 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_unref_ 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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