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RIOT/sys/luid/luid.c
2020-10-22 11:29:27 +02:00

136 lines
2.7 KiB
C

/*
* Copyright (C) 2017 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup sys_luid
* @{
*
* @file
* @brief LUID module implementation
*
* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
*
* @}
*/
#include <stdint.h>
#include <string.h>
#include "periph/cpuid.h"
#include "luid.h"
#if CPUID_LEN
/* based on DJB2 Hash */
static void _luid_round(const uint8_t *in, size_t in_len, uint8_t *out, size_t out_len)
{
uint32_t hash = 5381;
for (size_t i = 0; i < in_len; i++) {
hash = hash * 33 + in[i];
out[i % out_len] ^= hash;
}
}
#endif
void __attribute__((weak)) luid_base(void *buf, size_t len)
{
memset(buf, LUID_BACKUP_SEED, len);
#if CPUID_LEN
uint8_t cid[CPUID_LEN];
cpuid_get(cid);
_luid_round(cid, sizeof(cid), buf, len);
_luid_round(buf, len, buf, len);
#endif
}
static uint8_t lastused;
void luid_get(void *buf, size_t len)
{
luid_base(buf, len);
((uint8_t *)buf)[0] ^= lastused++;
}
void luid_get_lb(void *buf, size_t len)
{
luid_base(buf, len);
((uint8_t *)buf)[len - 1] ^= lastused++;
}
void luid_custom(void *buf, size_t len, int gen)
{
luid_base(buf, len);
for (size_t i = 0; i < sizeof(gen); i++) {
((uint8_t *)buf)[i % len] ^= ((gen >> (i * 8)) & 0xff);
}
}
void luid_get_short(network_uint16_t *addr)
{
luid_base(addr, sizeof(*addr));
addr->u8[1] ^= lastused++;
/* https://tools.ietf.org/html/rfc4944#section-12 requires the first bit to
* 0 for unicast addresses */
addr->u8[0] &= 0x7F;
}
void luid_get_eui48(eui48_t *addr)
{
luid_base(addr, sizeof(*addr));
addr->uint8[5] ^= lastused++;
eui48_set_local(addr);
eui48_clear_group(addr);
}
void luid_netdev_get_eui48(const netdev_t *netdev, eui48_t *addr)
{
luid_base(addr, sizeof(*addr));
#ifdef MODULE_NETDEV_REGISTER
addr->uint8[4] ^= netdev->type;
addr->uint8[5] ^= netdev->index;
#else
/* we should only get here with gnrc_netif_single */
(void)netdev;
#endif
eui48_set_local(addr);
eui48_clear_group(addr);
}
void luid_get_eui64(eui64_t *addr)
{
luid_base(addr, sizeof(*addr));
addr->uint8[7] ^= lastused++;
eui64_set_local(addr);
eui64_clear_group(addr);
}
void luid_netdev_get_eui64(const netdev_t *netdev, eui64_t *addr)
{
luid_base(addr, sizeof(*addr));
#ifdef MODULE_NETDEV_REGISTER
addr->uint8[6] ^= netdev->type;
addr->uint8[7] ^= netdev->index;
#else
/* we should only get here with gnrc_netif_single */
(void)netdev;
#endif
eui64_set_local(addr);
eui64_clear_group(addr);
}