1 /* 2 * Copyright (C) 2018 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define __BTSTACK_FILE__ "att_delayed_response.c" 39 40 // ***************************************************************************** 41 /* EXAMPLE_START(att_delayed_response): LE Peripheral - Delayed Response 42 * 43 * @text If the value for a GATT Chararacteristic isn't availabl for read, 44 * the value ATT_READ_RESPONSE_PENDING can be returned. When the value is available, 45 * att_server_response_ready is then called to complete the ATT request. 46 * 47 * Similarly, the error code ATT_ERROR_WRITE_RESPONSE_PENING can be returned when 48 * it is unclear if a write can be performed or not. When the decision was made, 49 * att_server_response_ready is is then called to complete the ATT request. 50 */ 51 // ***************************************************************************** 52 53 #include <stdint.h> 54 #include <stdio.h> 55 #include <stdlib.h> 56 #include <string.h> 57 58 #include "att_delayed_response.h" 59 #include "btstack.h" 60 61 #define ATT_VALUE_DELAY_MS 3000 62 #define ATT_VALUE_INVALID_MS 5000 63 64 /* @section Main Application Setup 65 * 66 * @text Listing MainConfiguration shows main application code. 67 * It initializes L2CAP, the Security Manager and configures the ATT Server with the pre-compiled 68 * ATT Database generated from $le_counter.gatt$. 69 * Additionally, it enables the Battery Service Server with the current battery level. 70 * Finally, it configures the advertisements and boots the Bluetooth stack. 71 * In this example, the Advertisement contains the Flags attribute and the device name. 72 * The flag 0x06 indicates: LE General Discoverable Mode and BR/EDR not supported. 73 */ 74 75 /* LISTING_START(MainConfiguration): Init L2CAP SM ATT Server */ 76 #ifdef ENABLE_ATT_DELAYED_RESPONSE 77 static btstack_timer_source_t att_timer; 78 static hci_con_handle_t con_handle; 79 static int value_ready; 80 #endif 81 82 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); 83 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); 84 85 const uint8_t adv_data[] = { 86 // Flags general discoverable, BR/EDR not supported 87 0x02, 0x01, 0x06, 88 // Name 89 0x08, 0x09, 'D', 'e', 'l', 'a', 'y', 'e', 'd', 90 }; 91 const uint8_t adv_data_len = sizeof(adv_data); 92 93 const char * test_string = "Delayed response"; 94 95 static void example_setup(void){ 96 97 l2cap_init(); 98 99 // setup le device db 100 le_device_db_init(); 101 102 // setup SM: Display only 103 sm_init(); 104 105 // setup ATT server 106 att_server_init(profile_data, att_read_callback, att_write_callback); 107 108 // setup advertisements 109 uint16_t adv_int_min = 0x0030; 110 uint16_t adv_int_max = 0x0030; 111 uint8_t adv_type = 0; 112 bd_addr_t null_addr; 113 memset(null_addr, 0, 6); 114 gap_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 0, null_addr, 0x07, 0x00); 115 gap_advertisements_set_data(adv_data_len, (uint8_t*) adv_data); 116 gap_advertisements_enable(1); 117 } 118 /* LISTING_END */ 119 120 /* 121 * @section att_invalidate_value Handler 122 * 123 * @text The att_invalidate_value handler 'invalidates' the value of the single Characteristic provided in this example 124 */ 125 #ifdef ENABLE_ATT_DELAYED_RESPONSE 126 static void att_invalidate_value(struct btstack_timer_source *ts){ 127 UNUSED(ts); 128 printf("Value got stale\n"); 129 value_ready = 0; 130 } 131 #endif 132 133 /* 134 * @section att_update_value Handler 135 * 136 * @text The att_update_value handler 'updates' the value of the single Characteristic provided in this example 137 */ 138 139 /* LISTING_START(att_read_delay): ATT Read Delay Handler */ 140 #ifdef ENABLE_ATT_DELAYED_RESPONSE 141 static void att_update_value(struct btstack_timer_source *ts){ 142 UNUSED(ts); 143 value_ready = 1; 144 145 // trigger ATT Server to try request again 146 int status = att_server_response_ready(con_handle); 147 148 printf("Value updated -> complete ATT request - status %02x\n", status); 149 150 // simulated value becoming stale again 151 att_timer.process = &att_invalidate_value; 152 btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS); 153 btstack_run_loop_add_timer(&att_timer); 154 } 155 #endif 156 157 /* LISTING_END */ 158 159 /* 160 * @section ATT Read 161 * 162 * @text The ATT Server handles all reads to constant data. For dynamic data like the custom characteristic, the registered 163 * att_read_callback is called. To handle long characteristics and long reads, the att_read_callback is first called 164 * with buffer == NULL, to request the total value length. Then it will be called again requesting a chunk of the value. 165 * See Listing attRead. 166 */ 167 168 /* LISTING_START(attRead): ATT Read */ 169 170 // ATT Client Read Callback for Dynamic Data 171 // - if buffer == NULL, don't copy data, just return size of value 172 // - if buffer != NULL, copy data and return number bytes copied 173 // @param offset defines start of attribute value 174 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){ 175 176 #ifdef ENABLE_ATT_DELAYED_RESPONSE 177 switch (att_handle){ 178 case ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE: 179 if (value_ready){ 180 return att_read_callback_handle_blob((const uint8_t *)test_string, strlen(test_string), offset, buffer, buffer_size); 181 } else { 182 printf("Read callback for handle %02x, but value not ready -> report response pending\n", att_handle); 183 con_handle = connection_handle; 184 return ATT_READ_RESPONSE_PENDING; 185 } 186 break; 187 case ATT_READ_RESPONSE_PENDING: 188 // virtual handle indicating all attributes have been queried 189 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); 190 // simulated delayed response for example 191 att_timer.process = &att_update_value; 192 btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS); 193 btstack_run_loop_add_timer(&att_timer); 194 return 0; 195 default: 196 break; 197 } 198 #else 199 UNUSED(connection_handle); 200 // useless code when ENABLE_ATT_DELAYED_RESPONSE is not defined - but avoids built errors 201 if (att_handle == ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE){ 202 printf("ENABLE_ATT_DELAYED_RESPONSE not defined in btstack_config.h, responding right away"); 203 return att_read_callback_handle_blob((const uint8_t *)test_string, strlen(test_string), offset, buffer, buffer_size); 204 } 205 #endif 206 207 return 0; 208 } 209 210 /* 211 * @section ATT Write 212 * */ 213 214 /* LISTING_START(attWrite): ATT Write */ 215 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){ 216 UNUSED(transaction_mode); 217 UNUSED(offset); 218 UNUSED(buffer_size); 219 UNUSED(connection_handle); 220 221 if (att_handle == ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE) { 222 printf("Write request, value: "); 223 printf_hexdump(buffer, buffer_size); 224 #ifdef ENABLE_ATT_DELAYED_RESPONSE 225 if (value_ready){ 226 printf("Write callback, value ready\n"); 227 return 0; 228 } else { 229 printf("Write callback for handle %02x, but not ready -> return response pending\n", att_handle); 230 } 231 // simulated delayed response for example 232 att_timer.process = &att_update_value; 233 btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS); 234 btstack_run_loop_add_timer(&att_timer); 235 return ATT_ERROR_WRITE_RESPONSE_PENDING; 236 #else 237 printf("ENABLE_ATT_DELAYED_RESPONSE not defined in btstack_config.h, responding right away"); 238 return 0; 239 #endif 240 } 241 return 0; 242 } 243 244 /* LISTING_END */ 245 246 int btstack_main(void); 247 int btstack_main(void) 248 { 249 example_setup(); 250 251 // turn on! 252 hci_power_control(HCI_POWER_ON); 253 254 return 0; 255 } 256 /* EXAMPLE_END */ 257