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 BLUEKITCHEN
24 * GMBH 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 "btstack.h"
59
60 // att_delayed_response.gatt contains the declaration of the provided GATT Services + Characteristics
61 // att_delayed_response.h contains the binary representation of att_delayed_response.gatt
62 // it is generated by the build system by calling: $BTSTACK_ROOT/tool/compile_gatt.py att_delayed_response.gatt att_delayed_response.h
63 // it needs to be regenerated when the GATT Database declared in att_delayed_response.gatt file is modified
64 #include "att_delayed_response.h"
65
66 #define ATT_VALUE_DELAY_MS 3000
67 #define ATT_VALUE_INVALID_MS 5000
68
69 /* @section Main Application Setup
70 *
71 * @text Listing MainConfiguration shows main application code.
72 * It initializes L2CAP, the Security Manager and configures the ATT Server with the pre-compiled
73 * ATT Database generated from $att_delayed_response.gatt$.
74 * Additionally, it enables the Battery Service Server with the current battery level.
75 * Finally, it configures the advertisements and boots the Bluetooth stack.
76 * In this example, the Advertisement contains the Flags attribute and the device name.
77 * The flag 0x06 indicates: LE General Discoverable Mode and BR/EDR not supported.
78 */
79
80 /* LISTING_START(MainConfiguration): Init L2CAP SM ATT Server */
81 #ifdef ENABLE_ATT_DELAYED_RESPONSE
82 static btstack_timer_source_t att_timer;
83 static hci_con_handle_t con_handle;
84 static int value_ready;
85 #endif
86
87 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);
88 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);
89
90 const uint8_t adv_data[] = {
91 // Flags general discoverable, BR/EDR not supported
92 0x02, 0x01, 0x06,
93 // Name
94 0x08, 0x09, 'D', 'e', 'l', 'a', 'y', 'e', 'd',
95 };
96 const uint8_t adv_data_len = sizeof(adv_data);
97
98 const char * test_string = "Delayed response";
99
example_setup(void)100 static void example_setup(void){
101
102 l2cap_init();
103
104 // setup SM: Display only
105 sm_init();
106
107 // setup ATT server
108 att_server_init(profile_data, att_read_callback, att_write_callback);
109
110 // setup advertisements
111 uint16_t adv_int_min = 0x0030;
112 uint16_t adv_int_max = 0x0030;
113 uint8_t adv_type = 0;
114 bd_addr_t null_addr;
115 memset(null_addr, 0, 6);
116 gap_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 0, null_addr, 0x07, 0x00);
117 gap_advertisements_set_data(adv_data_len, (uint8_t*) adv_data);
118 gap_advertisements_enable(1);
119 }
120 /* LISTING_END */
121
122 /*
123 * @section att_invalidate_value Handler
124 *
125 * @text The att_invalidate_value handler 'invalidates' the value of the single Characteristic provided in this example
126 */
127 #ifdef ENABLE_ATT_DELAYED_RESPONSE
att_invalidate_value(struct btstack_timer_source * ts)128 static void att_invalidate_value(struct btstack_timer_source *ts){
129 UNUSED(ts);
130 printf("Value got stale\n");
131 value_ready = 0;
132 }
133 #endif
134
135 /*
136 * @section att_update_value Handler
137 *
138 * @text The att_update_value handler 'updates' the value of the single Characteristic provided in this example
139 */
140
141 /* LISTING_START(att_read_delay): ATT Read Delay Handler */
142 #ifdef ENABLE_ATT_DELAYED_RESPONSE
att_update_value(struct btstack_timer_source * ts)143 static void att_update_value(struct btstack_timer_source *ts){
144 UNUSED(ts);
145 value_ready = 1;
146
147 // trigger ATT Server to try request again
148 int status = att_server_response_ready(con_handle);
149
150 printf("Value updated -> complete ATT request - status 0x%02x\n", status);
151
152 // simulated value becoming stale again
153 att_timer.process = &att_invalidate_value;
154 btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS);
155 btstack_run_loop_add_timer(&att_timer);
156 }
157 #endif
158
159 /* LISTING_END */
160
161 /*
162 * @section ATT Read
163 *
164 * @text The ATT Server handles all reads to constant data. For dynamic data like the custom characteristic, the registered
165 * att_read_callback is called. To handle long characteristics and long reads, the att_read_callback is first called
166 * with buffer == NULL, to request the total value length. Then it will be called again requesting a chunk of the value.
167 * See Listing attRead.
168 */
169
170 /* LISTING_START(attRead): ATT Read */
171
172 // ATT Client Read Callback for Dynamic Data
173 // - if buffer == NULL, don't copy data, just return size of value
174 // - if buffer != NULL, copy data and return number bytes copied
175 // @param offset defines start of attribute value
att_read_callback(hci_con_handle_t connection_handle,uint16_t att_handle,uint16_t offset,uint8_t * buffer,uint16_t buffer_size)176 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){
177
178 #ifdef ENABLE_ATT_DELAYED_RESPONSE
179 switch (att_handle){
180 case ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE:
181 if (value_ready){
182 return att_read_callback_handle_blob((const uint8_t *)test_string, strlen(test_string), offset, buffer, buffer_size);
183 } else {
184 printf("Read callback for handle 0x%02x, but value not ready -> report response pending\n", att_handle);
185 con_handle = connection_handle;
186 return ATT_READ_RESPONSE_PENDING;
187 }
188 break;
189 case ATT_READ_RESPONSE_PENDING:
190 // virtual handle indicating all attributes have been queried
191 printf("Read callback for virtual handle 0x%02x - all attributes have been queried (important for read multiple or read by type) -> start updating values\n", att_handle);
192 // simulated delayed response for example
193 att_timer.process = &att_update_value;
194 btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS);
195 btstack_run_loop_add_timer(&att_timer);
196 return 0;
197 default:
198 break;
199 }
200 #else
201 UNUSED(connection_handle);
202 // useless code when ENABLE_ATT_DELAYED_RESPONSE is not defined - but avoids built errors
203 if (att_handle == ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE){
204 printf("ENABLE_ATT_DELAYED_RESPONSE not defined in btstack_config.h, responding right away");
205 return att_read_callback_handle_blob((const uint8_t *)test_string, (uint16_t) strlen(test_string), offset, buffer, buffer_size);
206 }
207 #endif
208
209 return 0;
210 }
211
212 /*
213 * @section ATT Write
214 * */
215
216 /* LISTING_START(attWrite): ATT Write */
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)217 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){
218 UNUSED(transaction_mode);
219 UNUSED(offset);
220 UNUSED(buffer_size);
221 UNUSED(connection_handle);
222
223 if (att_handle == ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE) {
224 printf("Write request, value: ");
225 printf_hexdump(buffer, buffer_size);
226 #ifdef ENABLE_ATT_DELAYED_RESPONSE
227 if (value_ready){
228 printf("Write callback, value ready\n");
229 return 0;
230 } else {
231 printf("Write callback for handle 0x%02x, but not ready -> return response pending\n", att_handle);
232 }
233 // simulated delayed response for example
234 att_timer.process = &att_update_value;
235 btstack_run_loop_set_timer(&att_timer, ATT_VALUE_DELAY_MS);
236 btstack_run_loop_add_timer(&att_timer);
237 return ATT_ERROR_WRITE_RESPONSE_PENDING;
238 #else
239 printf("ENABLE_ATT_DELAYED_RESPONSE not defined in btstack_config.h, responding right away");
240 return 0;
241 #endif
242 }
243 return 0;
244 }
245
246 /* LISTING_END */
247
248 int btstack_main(void);
btstack_main(void)249 int btstack_main(void)
250 {
251 example_setup();
252
253 // turn on!
254 hci_power_control(HCI_POWER_ON);
255
256 return 0;
257 }
258 /* EXAMPLE_END */
259