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RIOT/sys/luid/luid.c 1.11 KB
a752c7ab   elopes   add first test an...
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  /*
   * Copyright (C) 2017 Freie Universitรคt 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 "assert.h"
  #include "periph/cpuid.h"
  
  #include "luid.h"
  
  static uint8_t lastused = 1;
  
  void luid_get(void *buf, size_t len)
  {
      luid_base(buf, len);
  
      ((uint8_t *)buf)[0] ^= 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_base(void *buf, size_t len)
  {
      assert(buf && (len > 0));
  
      memset(buf, LUID_BACKUP_SEED, len);
  
  #if CPUID_LEN
      uint8_t *out = (uint8_t *)buf;
      uint8_t cid[CPUID_LEN];
  
      cpuid_get(cid);
      for (size_t i = 0; i < CPUID_LEN; i++) {
          out[i % len] ^= cid[i];
      }
  #endif
  }