/* * Copyright (C) 2018 BlueKitchen GmbH * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the copyright holders nor the names of * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * 4. Any redistribution, use, or modification is done solely for * personal benefit and not for any commercial purpose or for * monetary gain. * * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * Please inquire about commercial licensing options at * contact@bluekitchen-gmbh.com * */ #define BTSTACK_FILE__ "att_delayed_response.c" // ***************************************************************************** /* EXAMPLE_START(att_delayed_response): LE Peripheral - Delayed Response * * @text If the value for a GATT Chararacteristic isn't availabl for read, * the value ATT_READ_RESPONSE_PENDING can be returned. When the value is available, * att_server_response_ready is then called to complete the ATT request. * * Similarly, the error code ATT_ERROR_WRITE_RESPONSE_PENING can be returned when * it is unclear if a write can be performed or not. When the decision was made, * att_server_response_ready is is then called to complete the ATT request. */ // ***************************************************************************** #include #include #include #include #include "btstack.h" // att_delayed_response.gatt contains the declaration of the provided GATT Services + Characteristics // att_delayed_response.h contains the binary representation of att_delayed_response.gatt // it is generated by the build system by calling: $BTSTACK_ROOT/tool/compile_gatt.py att_delayed_response.gatt att_delayed_response.h // it needs to be regenerated when the GATT Database declared in att_delayed_response.gatt file is modified #include "att_delayed_response.h" #define ATT_VALUE_DELAY_MS 3000 #define ATT_VALUE_INVALID_MS 5000 /* @section Main Application Setup * * @text Listing MainConfiguration shows main application code. * It initializes L2CAP, the Security Manager and configures the ATT Server with the pre-compiled * ATT Database generated from $att_delayed_response.gatt$. * Additionally, it enables the Battery Service Server with the current battery level. * Finally, it configures the advertisements and boots the Bluetooth stack. * In this example, the Advertisement contains the Flags attribute and the device name. * The flag 0x06 indicates: LE General Discoverable Mode and BR/EDR not supported. */ /* LISTING_START(MainConfiguration): Init L2CAP SM ATT Server */ #ifdef ENABLE_ATT_DELAYED_RESPONSE static btstack_timer_source_t att_timer; static hci_con_handle_t con_handle; static int value_ready; #endif static uint16_t att_read_callback(hci_con_handle_t con_handle, uint16_t att_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size); static int att_write_callback(hci_con_handle_t connection_handle, uint16_t att_handle, uint16_t transaction_mode, uint16_t offset, uint8_t *buffer, uint16_t buffer_size); const uint8_t adv_data[] = { // Flags general discoverable, BR/EDR not supported 0x02, 0x01, 0x06, // Name 0x08, 0x09, 'D', 'e', 'l', 'a', 'y', 'e', 'd', }; const uint8_t adv_data_len = sizeof(adv_data); const char * test_string = "Delayed response"; static void example_setup(void){ l2cap_init(); // setup le device db le_device_db_init(); // setup SM: Display only sm_init(); // setup ATT server att_server_init(profile_data, att_read_callback, att_write_callback); // setup advertisements uint16_t adv_int_min = 0x0030; uint16_t adv_int_max = 0x0030; uint8_t adv_type = 0; bd_addr_t null_addr; memset(null_addr, 0, 6); gap_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 0, null_addr, 0x07, 0x00); gap_advertisements_set_data(adv_data_len, (uint8_t*) adv_data); gap_advertisements_enable(1); } /* LISTING_END */ /* * @section att_invalidate_value Handler * * @text The att_invalidate_value handler 'invalidates' the value of the single Characteristic provided in this example */ #ifdef ENABLE_ATT_DELAYED_RESPONSE static void att_invalidate_value(struct btstack_timer_source *ts){ UNUSED(ts); printf("Value got stale\n"); value_ready = 0; } #endif /* * @section att_update_value Handler * * @text The att_update_value handler 'updates' the value of the single Characteristic provided in this example */ /* LISTING_START(att_read_delay): ATT Read Delay Handler */ #ifdef ENABLE_ATT_DELAYED_RESPONSE static void att_update_value(struct btstack_timer_source *ts){ UNUSED(ts); value_ready = 1; // trigger ATT Server to try request again int status = att_server_response_ready(con_handle); printf("Value updated -> complete ATT request - status %02x\n", status); // simulated value becoming stale again att_timer.process = &att_invalidate_value; btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS); btstack_run_loop_add_timer(&att_timer); } #endif /* LISTING_END */ /* * @section ATT Read * * @text The ATT Server handles all reads to constant data. For dynamic data like the custom characteristic, the registered * att_read_callback is called. To handle long characteristics and long reads, the att_read_callback is first called * with buffer == NULL, to request the total value length. Then it will be called again requesting a chunk of the value. * See Listing attRead. */ /* LISTING_START(attRead): ATT Read */ // ATT Client Read Callback for Dynamic Data // - if buffer == NULL, don't copy data, just return size of value // - if buffer != NULL, copy data and return number bytes copied // @param offset defines start of attribute value static uint16_t att_read_callback(hci_con_handle_t connection_handle, uint16_t att_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){ #ifdef ENABLE_ATT_DELAYED_RESPONSE switch (att_handle){ case ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE: if (value_ready){ return att_read_callback_handle_blob((const uint8_t *)test_string, strlen(test_string), offset, buffer, buffer_size); } else { printf("Read callback for handle %02x, but value not ready -> report response pending\n", att_handle); con_handle = connection_handle; return ATT_READ_RESPONSE_PENDING; } break; case ATT_READ_RESPONSE_PENDING: // virtual handle indicating all attributes have been queried printf("Read callback for virtual handle %02x - all attributes have been queried (important for read multiple or read by type) -> start updating values\n", att_handle); // simulated delayed response for example att_timer.process = &att_update_value; btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS); btstack_run_loop_add_timer(&att_timer); return 0; default: break; } #else UNUSED(connection_handle); // useless code when ENABLE_ATT_DELAYED_RESPONSE is not defined - but avoids built errors if (att_handle == ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE){ printf("ENABLE_ATT_DELAYED_RESPONSE not defined in btstack_config.h, responding right away"); return att_read_callback_handle_blob((const uint8_t *)test_string, strlen(test_string), offset, buffer, buffer_size); } #endif return 0; } /* * @section ATT Write * */ /* LISTING_START(attWrite): ATT Write */ static int att_write_callback(hci_con_handle_t connection_handle, uint16_t att_handle, uint16_t transaction_mode, uint16_t offset, uint8_t *buffer, uint16_t buffer_size){ UNUSED(transaction_mode); UNUSED(offset); UNUSED(buffer_size); UNUSED(connection_handle); if (att_handle == ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE) { printf("Write request, value: "); printf_hexdump(buffer, buffer_size); #ifdef ENABLE_ATT_DELAYED_RESPONSE if (value_ready){ printf("Write callback, value ready\n"); return 0; } else { printf("Write callback for handle %02x, but not ready -> return response pending\n", att_handle); } // simulated delayed response for example att_timer.process = &att_update_value; btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS); btstack_run_loop_add_timer(&att_timer); return ATT_ERROR_WRITE_RESPONSE_PENDING; #else printf("ENABLE_ATT_DELAYED_RESPONSE not defined in btstack_config.h, responding right away"); return 0; #endif } return 0; } /* LISTING_END */ int btstack_main(void); int btstack_main(void) { example_setup(); // turn on! hci_power_control(HCI_POWER_ON); return 0; } /* EXAMPLE_END */