text: /**
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  /**
   * @file
   * @brief Implementation of Gazell Pairing Library (gzp), Common functions.
   * @defgroup gzp_source_common Gazell Pairing common functions implementation
   * @{
   * @ingroup gzp_04_source
   */
  
  
  #include "nrf_gzp.h"
  #include "nrf_gzll.h"
  #include "nrf_ecb.h"
  #include <string.h>
  
  
  #define SOURCE_FILE NRF_SOURCE_FILE_GZP    ///< File identifer for asserts.
  
  
  /******************************************************************************/
  /** @name Global variables
   *  @{ */
  /******************************************************************************/
  
  /**
   * Constant holding base address part of the pairing address.
   */
  static const uint8_t pairing_base_address[4] = { GZP_ADDRESS };
  
  /**
   * Constant holding prefix byte of the pairing address.
   */
  static const uint8_t pairing_address_prefix_byte = 0;
  
  /**
   * Constant holding pre-defined "validation ID".
   */
  static const uint8_t gzp_validation_id[GZP_VALIDATION_ID_LENGTH] = GZP_VALIDATION_ID;
  
  /**
   * Constant holding pre-defined "secret key".
   */
  static const uint8_t gzp_secret_key[16] = GZP_SECRET_KEY;
  
  /**
   * Variable used for AES key selection
   */
  static gzp_key_select_t gzp_key_select;
  
  
  /** @} */
  
  
  /******************************************************************************/
  /** @name Misc. external variables.
   *  @{ */
  /******************************************************************************/
  static uint8_t gzp_session_token[GZP_SESSION_TOKEN_LENGTH];
  static uint8_t gzp_dyn_key[GZP_DYN_KEY_LENGTH];
  
  /** @} */
  
  /******************************************************************************/
  /** @name Implementation common internal GZP functions
   *  @{ */
  /******************************************************************************/
  bool gzp_update_radio_params(const uint8_t* system_address)
  {
      uint8_t i;
      uint8_t channels[NRF_GZLL_CONST_MAX_CHANNEL_TABLE_SIZE];
      uint32_t channel_table_size;
      uint32_t pairing_base_address_32, system_address_32;
      bool update_ok = true;
      bool gzll_enabled_state;
  
      gzll_enabled_state = nrf_gzll_is_enabled();
  
      // Configure "global" pairing address
      pairing_base_address_32 = (pairing_base_address[0])       +
      ((uint32_t)pairing_base_address[1] <<  8) +
      ((uint32_t)pairing_base_address[2] << 16) +
      ((uint32_t)pairing_base_address[3] << 24) ;
      if (system_address != NULL)
      {
          system_address_32 = (system_address[0])       +
          ((uint32_t)system_address[1] <<  8) +
          ((uint32_t)system_address[2] << 16) +
          ((uint32_t)system_address[3] << 24) ;
      }
      else
      {
          return false;
      }
  
      nrf_gzp_disable_gzll();
      update_ok = update_ok && nrf_gzll_set_base_address_0(pairing_base_address_32);
      update_ok = update_ok && nrf_gzll_set_address_prefix_byte(GZP_PAIRING_PIPE, pairing_address_prefix_byte);
      update_ok = update_ok && nrf_gzll_set_base_address_1(system_address_32);
  
      // Configure address for pipe 1 - 5. Address byte set to equal pipe number.
      for (i = 1; i < NRF_GZLL_CONST_PIPE_COUNT; i++)
      {
          update_ok = update_ok && nrf_gzll_set_address_prefix_byte(i,i);
      }
  
      channel_table_size = nrf_gzll_get_channel_table_size();
      gzp_generate_channels(&channels[0], system_address, channel_table_size);
  
      // Write generated channel subset to Gazell Link Layer
      update_ok = update_ok && nrf_gzll_set_channel_table(&channels[0], channel_table_size);
      if (gzll_enabled_state)
      {
          update_ok = update_ok && nrf_gzll_enable();
      }
      return update_ok;
  }
  
  void gzp_generate_channels(uint8_t* ch_dst, const uint8_t* system_address, uint8_t channel_tab_size)
  {
      uint8_t binsize, spacing, i;
  
      binsize = (GZP_CHANNEL_MAX - GZP_CHANNEL_MIN) / channel_tab_size;
  
      ch_dst[0] = GZP_CHANNEL_LOW;
      ch_dst[channel_tab_size - 1] = GZP_CHANNEL_HIGH;
  
      if (system_address != NULL)
      {
          for (i = 1; i < (channel_tab_size - 1); i++)
          {
              ch_dst[i] = (binsize * i) + (system_address[i % 4] % binsize);
          }
      }
  
      // If channels are too close, shift them to better positions
      for (i = 1; i < channel_tab_size; i++)
      {
          spacing = (ch_dst[i] - ch_dst[i - 1]);
          if (spacing < GZP_CHANNEL_SPACING_MIN)
          {
              ch_dst[i] += (GZP_CHANNEL_SPACING_MIN - spacing);
          }
      }
  }
  
  __INLINE void nrf_gzp_disable_gzll(void)
  {
      if (nrf_gzll_is_enabled())
      {
          nrf_gzll_disable();
          __WFI();
          while (nrf_gzll_is_enabled())
          {
          }
      }
  }
  
  #ifndef GZP_CRYPT_DISABLE
  
  void gzp_xor_cipher(uint8_t* dst, const uint8_t* src, const uint8_t* pad, uint8_t length)
  {
      uint8_t i;
  
      for (i = 0; i < length; i++)
      {
          *dst = *src ^ *pad;
          dst++;
          src++;
          pad++;
      }
  }
  
  bool gzp_validate_id(const uint8_t* id)
  {
      return (memcmp(id, (void*)gzp_validation_id, GZP_VALIDATION_ID_LENGTH) == 0);
  }
  
  void gzp_add_validation_id(uint8_t* dst)
  {
      memcpy(dst, (void const*)gzp_validation_id, GZP_VALIDATION_ID_LENGTH);
  }
  
  void gzp_crypt_set_session_token(const uint8_t * token)
  {
      memcpy(gzp_session_token, (void const*)token, GZP_SESSION_TOKEN_LENGTH);
  }
  
  void gzp_crypt_set_dyn_key(const uint8_t* key)
  {
      memcpy(gzp_dyn_key, (void const*)key, GZP_DYN_KEY_LENGTH);
  }
  
  void gzp_crypt_get_session_token(uint8_t * dst_token)
  {
      memcpy(dst_token, (void const*)gzp_session_token, GZP_SESSION_TOKEN_LENGTH);
  }
  
  void gzp_crypt_get_dyn_key(uint8_t* dst_key)
  {
      memcpy(dst_key, (void const*)gzp_dyn_key, GZP_DYN_KEY_LENGTH);
  }
  
  void gzp_crypt_select_key(gzp_key_select_t key_select)
  {
      gzp_key_select = key_select;
  }
  
  void gzp_crypt(uint8_t* dst, const uint8_t* src, uint8_t length)
  {
      uint8_t i;
      uint8_t key[16];
      uint8_t iv[16];
  
      // Build AES key based on "gzp_key_select"
  
      switch (gzp_key_select)
      {
      case GZP_ID_EXCHANGE:
          memcpy(key, (void const*)gzp_secret_key, 16);
          break;
      case GZP_KEY_EXCHANGE:
          memcpy(key, (void const*)gzp_secret_key, 16);
          gzp_get_host_id(key);
          break;
      case GZP_DATA_EXCHANGE:
          memcpy(key, (void const*)gzp_secret_key, 16);
          memcpy(key, (void const*)gzp_dyn_key, GZP_DYN_KEY_LENGTH);
          break;
      default:
          return;
      }
  
      // Build init vector from "gzp_session_token"
      for (i = 0; i < 16; i++)
      {
          if (i < GZP_SESSION_TOKEN_LENGTH)
          {
              iv[i] = gzp_session_token[i];
          }
          else
          {
              iv[i] = 0;
          }
      }
  
      // Set up hal_aes using new key and init vector
      (void)nrf_ecb_init();
      nrf_ecb_set_key(key);
      //hal_aes_setup(false, ECB, key, NULL); // Note, here we skip the IV as we use ECB mode
  
      // Encrypt IV using ECB mode
      (void)nrf_ecb_crypt(iv, iv);
  
      // Encrypt data by XOR'ing with AES output
      gzp_xor_cipher(dst, src, iv, length);
  
  }
  
  void gzp_random_numbers_generate(uint8_t * dst, uint8_t n)
  {
      uint8_t i;
  
      NRF_RNG->EVENTS_VALRDY=0;
      NRF_RNG->TASKS_START = 1;
      for (i = 0; i < n; i++)
      {
          while (NRF_RNG->EVENTS_VALRDY==0)
          {}
          dst[i] = (uint8_t)NRF_RNG->VALUE;
          NRF_RNG->EVENTS_VALRDY=0;
      }
      NRF_RNG->TASKS_STOP = 1;
  }
  
  
  /******************************************************************************/
  /** @name Implementation of nRF51 specific GZP functions
   *  @{ */
  /******************************************************************************/
  
  /**
  * @brief Function for setting the Primask variable. Only necessary if ARMCC
  * compiler skips __set_PRIMASK at high optimization levels.
  *
  * @param primask The primask value. 1 to disable interrupts, 0 otherwise.
  */
  static void nrf_gzp_set_primask(uint32_t primask)
  {
      #if defined(__CC_ARM)
      //lint -save -e10 -e618 -e438 -e550 -e526 -e628 -e526
      volatile register uint32_t __regPriMask         __ASM("primask");
      __regPriMask = (primask);
      #else
      __set_PRIMASK(primask);
      #endif
      //lint -restore
  }
  
  void nrf_gzp_flush_rx_fifo(uint32_t pipe)
  {
      static uint8_t dummy_packet[NRF_GZLL_CONST_MAX_PAYLOAD_LENGTH];
      uint32_t length;
  
      nrf_gzp_set_primask(1);
      while (nrf_gzll_get_rx_fifo_packet_count(pipe) >0)
      {
          length = NRF_GZLL_CONST_MAX_PAYLOAD_LENGTH;
          (void)nrf_gzll_fetch_packet_from_rx_fifo(pipe,dummy_packet,&length);
      }
      nrf_gzp_set_primask(0);
  }
  /** @} */
  
  
  
  /******************************************************************************/
  /** @name Implementation of debug functions
   *  @{ */
  /******************************************************************************/
  
  
  /** @} */
  
  /** @} */
  #endif
  