[nrf51822][SDK12.3] Implement whitelist fast broadcast in 3s, switch to whitelist slow broadcast indefinitely

1. Whitelist mechanism

White list is the simplest and most straightforward security mechanism in the BLE protocol.

The so-called whitelist is a group of Bluetooth addresses.

Through the whitelist, we can only allow specific Bluetooth devices (listed in the whitelist) to scan and connect to us.

You can also scan and connect only to specific Bluetooth devices (listed in the whitelist).

#define APP_ADV_FAST_INTERVAL 0x0028    /**< Fast advertising interval (in units of 0.625 ms. This value corresponds to 25 ms.). */

#define APP_ADV_SLOW_INTERVAL 0x0C80    /**< Slow advertising interval (in units of 0.625 ms. This value corrsponds to 2 seconds). */

#define APP_ADV_FAST_TIMEOUT 3  /**< The duration of the fast advertising period (in seconds). */

#define APP_ADV_SLOW_TIMEOUT 0  /**< The duration of the slow advertising period (in seconds). */

static void advertising_init(void)

{

    uint32_t               err_code;

    uint8_t                adv_flags;

    ble_advdata_t advdata;

    ble_adv_modes_config_t options;

    // Build and set advertising data

    memset(&advdata, 0, sizeof(advdata));

    adv_flags                       = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;//重点

    advdata.name_type               = BLE_ADVDATA_FULL_NAME;

    advdata.include_appearance      = true;

    advdata.flags                   = adv_flags;

    advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);

    advdata.uuids_complete.p_uuids  = m_adv_uuids;

    memset(&options, 0, sizeof(options));

    options.ble_adv_whitelist_enabled      = true;//重点

    options.ble_adv_directed_enabled       = true;

    options.ble_adv_directed_slow_enabled  = false;

    options.ble_adv_directed_slow_interval = 0;

    options.ble_adv_directed_slow_timeout  = 0;

    options.ble_adv_fast_enabled           = true;

    options.ble_adv_fast_interval          = APP_ADV_FAST_INTERVAL;

    options.ble_adv_fast_timeout           = APP_ADV_FAST_TIMEOUT;

    options.ble_adv_slow_enabled           = true;

    options.ble_adv_slow_interval          = APP_ADV_SLOW_INTERVAL;

    options.ble_adv_slow_timeout           = APP_ADV_SLOW_TIMEOUT;

    err_code = ble_advertising_init(&advdata,

                                    NULL,

                                    &options,

                                    on_adv_evt,

                                    ble_advertising_error_handler);

    APP_ERROR_CHECK(err_code);

}