android 蓝牙遥控器配对过程的一点理解

/*******************************************************************************
 *
 * Function         btm_ble_start_encrypt
 *
 * Description      This function is called to start LE encryption.
 *
 *
 * Returns          BTM_SUCCESS if encryption was started successfully
 *
 ******************************************************************************/

//debug_stamp           
tBTM_STATUS btm_ble_start_encrypt(const RawAddress& bda, bool use_stk,
                                  BT_OCTET16 stk) {
  tBTM_CB* p_cb = &btm_cb;
  tBTM_SEC_DEV_REC* p_rec = btm_find_dev(bda);
  BT_OCTET8 dummy_rand = {0};

  BTM_TRACE_ERROR("btm_ble_start_encrypt");

  if (!p_rec) {
    BTM_TRACE_ERROR("Link is not active, can not encrypt!");
    return BTM_WRONG_MODE;
  }

  if (p_rec->sec_state ==