ATT Server API

src/ble/att_server.h

/**
 * @title ATT Server
 *
 * @TLV 'BTC' x
 */

/*
 * @brief setup ATT server
 * @param db attribute database created by compile-gatt.py
 * @param read_callback, see att_db.h, can be NULL
 * @param write_callback, see attl.h, can be NULL
 */
void att_server_init(uint8_t const * db, att_read_callback_t read_callback, att_write_callback_t write_callback);

/**
 * @brief Enable support for Enhanced ATT bearer
 * @note Requires ENABLE_GATT_OVER_EATT
 * @param num_eatt_bearers
 * @param storage_buffer
 * @param storage_size must be >= num_eatt_bearers * sizeof(att_server_eatt_bearer_t)
 * @return status   ERROR_CODE_SUCCESS
 *                  ERROR_CODE_MEMORY_CAPACITY_EXCEEDED if buffer too small or no entry in l2cap service pool
 *                  L2CAP_SERVICE_ALREADY_REGISTERED if called twice
 */
uint8_t att_server_eatt_init(uint8_t num_eatt_bearers, uint8_t * storage_buffer, uint16_t storage_size);

/*
 * @brief register packet handler for ATT server events:
 *        - ATT_EVENT_CAN_SEND_NOW
 *        - ATT_EVENT_HANDLE_VALUE_INDICATION_COMPLETE
 *        - ATT_EVENT_MTU_EXCHANGE_COMPLETE 
 * @param handler
 */
void att_server_register_packet_handler(btstack_packet_handler_t handler);

/**
 * @brief register read/write callbacks for specific handle range
 * @param att_service_handler_t
 */
void att_server_register_service_handler(att_service_handler_t * handler);

/**
 * @brief Request callback when sending is possible
 * @note callback might happend during call to this function
 * @param callback_registration to point to callback function and context information
 * @param con_handle
 * @return 0 if ok, error otherwise
 */
uint8_t att_server_register_can_send_now_callback(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle);

/**
 * @brief Return ATT MTU
 * @param con_handle
 * @return mtu if ok, 0 otherwise
 */
uint16_t att_server_get_mtu(hci_con_handle_t con_handle);

/**
 * @brief Request callback when sending notifcation is possible
 * @note callback might happend during call to this function
 * @param callback_registration to point to callback function and context information
 * @param con_handle
 * @return ERROR_CODE_SUCCESS if ok, ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER if handle unknown, and ERROR_CODE_COMMAND_DISALLOWED if callback already registered
 */
uint8_t att_server_request_to_send_notification(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle);

/**
 * @brief Request callback when sending indication is possible
 * @note callback might happend during call to this function
 * @param callback_registration to point to callback function and context information
 * @param con_handle
 * @return ERROR_CODE_SUCCESS if ok, ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER if handle unknown, and ERROR_CODE_COMMAND_DISALLOWED if callback already registered
 */
uint8_t att_server_request_to_send_indication(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle);

/**
 * @brief notify client about attribute value change
 * @param con_handle
 * @param attribute_handle
 * @param value
 * @param value_len
 * @return 0 if ok, error otherwise
 */
uint8_t att_server_notify(hci_con_handle_t con_handle, uint16_t attribute_handle, const uint8_t *value, uint16_t value_len);

/**
 * @brief notify client about multiple attribute value changes
 * @param con_handle
 * @param num_attributes
 * @param attribute_handles[]
 * @param values_data[]
 * @param values_len[]
 * @return 0 if ok, error otherwise
 */
uint8_t att_server_multiple_notify(hci_con_handle_t con_handle, uint8_t num_attributes,
                                   const uint16_t * attribute_handles, const uint8_t ** values_data, const uint16_t * values_len);

/**
 * @brief indicate value change to client. client is supposed to reply with an indication_response
 * @param con_handle
 * @param attribute_handle
 * @param value
 * @param value_len
 * @return 0 if ok, error otherwise
 */
uint8_t att_server_indicate(hci_con_handle_t con_handle, uint16_t attribute_handle, const uint8_t *value, uint16_t value_len);

#ifdef ENABLE_ATT_DELAYED_RESPONSE
/**
 * @brief response ready - called after returning ATT_READ__RESPONSE_PENDING in an att_read_callback or
 * ATT_ERROR_WRITE_REQUEST_PENDING IN att_write_callback before to trigger callback again and complete the transaction
 * @nore The ATT Server will retry handling the current ATT request
 * @param con_handle
 * @return 0 if ok, error otherwise
 */
uint8_t att_server_response_ready(hci_con_handle_t con_handle);
#endif

/**
 * De-Init ATT Server 
 */
void att_server_deinit(void);

// the following functions will be removed soon

/**
 * @brief tests if a notification or indication can be send right now
 * @param con_handle
 * @return 1, if packet can be sent
 */
int  att_server_can_send_packet_now(hci_con_handle_t con_handle);

/**
 * @brief Request emission of ATT_EVENT_CAN_SEND_NOW as soon as possible
 * @note ATT_EVENT_CAN_SEND_NOW might be emitted during call to this function
 *       so packet handler should be ready to handle it
 * @param con_handle
 */
void att_server_request_can_send_now_event(hci_con_handle_t con_handle);
// end of deprecated functions