xref: /btstack/src/ble/gatt_client.h (revision abdc9fb59b2eadafc2464f74b9b2ad9a5ac43b00)
1 /*
2  * Copyright (C) 2014 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
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30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
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33  * Please inquire about commercial licensing options at
34  * [email protected]
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36  */
37 
38 
39 #ifndef btstack_gatt_client_h
40 #define btstack_gatt_client_h
41 
42 #include "hci.h"
43 
44 #if defined __cplusplus
45 extern "C" {
46 #endif
47 
48 typedef enum {
49     P_READY,
50     P_W2_SEND_SERVICE_QUERY,
51     P_W4_SERVICE_QUERY_RESULT,
52     P_W2_SEND_SERVICE_WITH_UUID_QUERY,
53     P_W4_SERVICE_WITH_UUID_RESULT,
54 
55     P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY,
56     P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT,
57     P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY,
58     P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT,
59 
60     P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY,
61     P_W4_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT,
62 
63     P_W2_SEND_INCLUDED_SERVICE_QUERY,
64     P_W4_INCLUDED_SERVICE_QUERY_RESULT,
65     P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY,
66     P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT,
67 
68     P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY,
69     P_W4_READ_CHARACTERISTIC_VALUE_RESULT,
70 
71     P_W2_SEND_READ_BLOB_QUERY,
72     P_W4_READ_BLOB_RESULT,
73 
74     P_W2_SEND_READ_BY_TYPE_REQUEST,
75     P_W4_READ_BY_TYPE_RESPONSE,
76 
77     P_W2_SEND_READ_MULTIPLE_REQUEST,
78     P_W4_READ_MULTIPLE_RESPONSE,
79 
80     P_W2_SEND_WRITE_CHARACTERISTIC_VALUE,
81     P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT,
82 
83     P_W2_PREPARE_WRITE,
84     P_W4_PREPARE_WRITE_RESULT,
85     P_W2_PREPARE_RELIABLE_WRITE,
86     P_W4_PREPARE_RELIABLE_WRITE_RESULT,
87 
88     P_W2_EXECUTE_PREPARED_WRITE,
89     P_W4_EXECUTE_PREPARED_WRITE_RESULT,
90     P_W2_CANCEL_PREPARED_WRITE,
91     P_W4_CANCEL_PREPARED_WRITE_RESULT,
92     P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH,
93     P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT,
94 
95 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
96     P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY,
97     P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT,
98 #else
99     P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY,
100     P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT,
101 #endif
102     P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION,
103     P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT,
104 
105     P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY,
106     P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT,
107 
108     P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY,
109     P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT,
110 
111     P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR,
112     P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT,
113 
114     // all long writes use this
115     P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR,
116     P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT,
117     P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR,
118     P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT,
119 
120     // gatt reliable write API use this (manual version of the above)
121     P_W2_PREPARE_WRITE_SINGLE,
122     P_W4_PREPARE_WRITE_SINGLE_RESULT,
123 
124     P_W4_CMAC_READY,
125     P_W4_CMAC_RESULT,
126     P_W2_SEND_SIGNED_WRITE,
127     P_W4_SEND_SINGED_WRITE_DONE,
128 } gatt_client_state_t;
129 
130 
131 typedef enum{
132     SEND_MTU_EXCHANGE,
133     SENT_MTU_EXCHANGE,
134     MTU_EXCHANGED,
135     MTU_AUTO_EXCHANGE_DISABLED
136 } gatt_client_mtu_t;
137 
138 typedef struct gatt_client{
139     btstack_linked_item_t    item;
140     // TODO: rename gatt_client_state -> state
141     gatt_client_state_t gatt_client_state;
142 
143     // user callback
144     btstack_packet_handler_t callback;
145 
146     // can write without response callback
147     btstack_packet_handler_t write_without_response_callback;
148 
149     hci_con_handle_t con_handle;
150 
151     uint8_t   address_type;
152     bd_addr_t address;
153 
154     uint16_t          mtu;
155     gatt_client_mtu_t mtu_state;
156 
157     uint16_t uuid16;
158     uint8_t  uuid128[16];
159 
160     uint16_t start_group_handle;
161     uint16_t end_group_handle;
162 
163     uint16_t query_start_handle;
164     uint16_t query_end_handle;
165 
166     uint8_t  characteristic_properties;
167     uint16_t characteristic_start_handle;
168 
169     uint16_t attribute_handle;
170     uint16_t attribute_offset;
171     uint16_t attribute_length;
172     uint8_t* attribute_value;
173 
174     // read multiple characteristic values
175     uint16_t    read_multiple_handle_count;
176     uint16_t  * read_multiple_handles;
177 
178     uint16_t client_characteristic_configuration_handle;
179     uint8_t  client_characteristic_configuration_value[2];
180 
181     uint8_t  filter_with_uuid;
182     uint8_t  send_confirmation;
183 
184     int      le_device_index;
185     uint8_t  cmac[8];
186 
187     btstack_timer_source_t gc_timeout;
188 
189 #ifdef ENABLE_GATT_CLIENT_PAIRING
190     uint8_t  security_counter;
191     uint8_t  wait_for_pairing_complete;
192     uint8_t  pending_error_code;
193 #endif
194 
195 } gatt_client_t;
196 
197 typedef struct gatt_client_notification {
198     btstack_linked_item_t    item;
199     btstack_packet_handler_t callback;
200     hci_con_handle_t con_handle;
201     uint16_t attribute_handle;
202 } gatt_client_notification_t;
203 
204 /* API_START */
205 
206 typedef struct {
207     uint16_t start_group_handle;
208     uint16_t end_group_handle;
209     uint16_t uuid16;
210     uint8_t  uuid128[16];
211 } gatt_client_service_t;
212 
213 typedef struct {
214     uint16_t start_handle;
215     uint16_t value_handle;
216     uint16_t end_handle;
217     uint16_t properties;
218     uint16_t uuid16;
219     uint8_t  uuid128[16];
220 } gatt_client_characteristic_t;
221 
222 typedef struct {
223     uint16_t handle;
224     uint16_t uuid16;
225     uint8_t  uuid128[16];
226 } gatt_client_characteristic_descriptor_t;
227 
228 /**
229  * @brief Set up GATT client.
230  */
231 void gatt_client_init(void);
232 
233 /**
234  * @brief MTU is available after the first query has completed. If status is equal to 0, it returns the real value, otherwise the default value of 23.
235  */
236 uint8_t gatt_client_get_mtu(hci_con_handle_t con_handle, uint16_t * mtu);
237 
238 /**
239 * @brief Sets whether a MTU Exchange Request shall be automatically send before the first attribute read request is send. Default is enable.d
240 */
241 void gatt_client_mtu_enable_auto_negotiation(uint8_t enabled);
242 
243 /**
244 * @brief Sends a MTU Exchange Request, this allows for the client to exchange MTU when gatt_client_mtu_enable_auto_negotiation is disabled.
245 */
246 void gatt_client_send_mtu_negotiation(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
247 
248 /**
249  * @brief Returns if the GATT client is ready to receive a query. It is used with daemon.
250  */
251 int gatt_client_is_ready(hci_con_handle_t con_handle);
252 
253 /**
254  * @brief Discovers all primary services. For each found service, an le_service_event_t with type set to GATT_EVENT_SERVICE_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t, with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of discovery.
255  */
256 uint8_t gatt_client_discover_primary_services(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
257 
258 /**
259  * @brief Discovers a specific primary service given its UUID. This service may exist multiple times. For each found service, an le_service_event_t with type set to GATT_EVENT_SERVICE_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t, with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of discovery.
260  */
261 uint8_t gatt_client_discover_primary_services_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t uuid16);
262 uint8_t gatt_client_discover_primary_services_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, const uint8_t  * uuid);
263 
264 /**
265  * @brief Finds included services within the specified service. For each found included service, an le_service_event_t with type set to GATT_EVENT_INCLUDED_SERVICE_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of discovery. Information about included service type (primary/secondary) can be retrieved either by sending an ATT find information request for the returned start group handle (returning the handle and the UUID for primary or secondary service) or by comparing the service to the list of all primary services.
266  */
267 uint8_t gatt_client_find_included_services_for_service(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t  *service);
268 
269 /**
270  * @brief Discovers all characteristics within the specified service. For each found characteristic, an le_characteristics_event_t with type set to GATT_EVENT_CHARACTERISTIC_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of discovery.
271  */
272 uint8_t gatt_client_discover_characteristics_for_service(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t  *service);
273 
274 /**
275  * @brief The following four functions are used to discover all characteristics within the specified service or handle range, and return those that match the given UUID. For each found characteristic, an le_characteristic_event_t with type set to GATT_EVENT_CHARACTERISTIC_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of discovery.
276  */
277 uint8_t gatt_client_discover_characteristics_for_handle_range_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t start_handle, uint16_t end_handle, uint16_t uuid16);
278 uint8_t gatt_client_discover_characteristics_for_handle_range_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t start_handle, uint16_t end_handle, uint8_t  * uuid);
279 uint8_t gatt_client_discover_characteristics_for_service_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t  *service, uint16_t  uuid16);
280 uint8_t gatt_client_discover_characteristics_for_service_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t  *service, uint8_t  * uuid128);
281 
282 /**
283  * @brief Discovers attribute handle and UUID of a characteristic descriptor within the specified characteristic. For each found descriptor, an le_characteristic_descriptor_event_t with type set to GATT_EVENT_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of discovery.
284  */
285 uint8_t gatt_client_discover_characteristic_descriptors(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t  *characteristic);
286 
287 /**
288  * @brief Reads the characteristic value using the characteristic's value handle. If the characteristic value is found, an le_characteristic_value_event_t with type set to GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of read.
289  */
290 uint8_t gatt_client_read_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t  *characteristic);
291 uint8_t gatt_client_read_value_of_characteristic_using_value_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t characteristic_value_handle);
292 
293 /**
294  * @brief Reads the characteric value of all characteristics with the uuid. For each found, an le_characteristic_value_event_t with type set to GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of read.
295  */
296 uint8_t gatt_client_read_value_of_characteristics_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t start_handle, uint16_t end_handle, uint16_t uuid16);
297 uint8_t gatt_client_read_value_of_characteristics_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t start_handle, uint16_t end_handle, uint8_t * uuid128);
298 
299 /**
300  * @brief Reads the long characteristic value using the characteristic's value handle. The value will be returned in several blobs. For each blob, an le_characteristic_value_event_t with type set to GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT and updated value offset will be generated and passed to the registered callback. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, mark the end of read.
301  */
302 uint8_t gatt_client_read_long_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t  *characteristic);
303 uint8_t gatt_client_read_long_value_of_characteristic_using_value_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t characteristic_value_handle);
304 uint8_t gatt_client_read_long_value_of_characteristic_using_value_handle_with_offset(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t characteristic_value_handle, uint16_t offset);
305 
306 /*
307  * @brief Read multiple characteristic values
308  * @param number handles
309  * @param list_of_handles list of handles
310  */
311 uint8_t gatt_client_read_multiple_characteristic_values(btstack_packet_handler_t callback, hci_con_handle_t con_handle, int num_value_handles, uint16_t * value_handles);
312 
313 /**
314  * @brief Writes the characteristic value using the characteristic's value handle without an acknowledgment that the write was successfully performed.
315  */
316 uint8_t gatt_client_write_value_of_characteristic_without_response(hci_con_handle_t con_handle, uint16_t characteristic_value_handle, uint16_t length, uint8_t  * data);
317 
318 /**
319  * @brief Writes the authenticated characteristic value using the characteristic's value handle without an acknowledgment that the write was successfully performed.
320  */
321 uint8_t gatt_client_signed_write_without_response(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t handle, uint16_t message_len, uint8_t  * message);
322 
323 /**
324  * @brief Writes the characteristic value using the characteristic's value handle. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of write. The write is successfully performed, if the event's status field is set to 0.
325  */
326 uint8_t gatt_client_write_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t characteristic_value_handle, uint16_t length, uint8_t  * data);
327 uint8_t gatt_client_write_long_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t characteristic_value_handle, uint16_t length, uint8_t  * data);
328 uint8_t gatt_client_write_long_value_of_characteristic_with_offset(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t characteristic_value_handle, uint16_t offset, uint16_t length, uint8_t  * data);
329 
330 /**
331  * @brief Writes of the long characteristic value using the characteristic's value handle. It uses server response to validate that the write was correctly received. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE marks the end of write. The write is successfully performed, if the event's status field is set to 0.
332  */
333 uint8_t gatt_client_reliable_write_long_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t characteristic_value_handle, uint16_t length, uint8_t  * data);
334 
335 /**
336  * @brief Reads the characteristic descriptor using its handle. If the characteristic descriptor is found, an le_characteristic_descriptor_event_t with type set to GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of read.
337  */
338 uint8_t gatt_client_read_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t  * descriptor);
339 uint8_t gatt_client_read_characteristic_descriptor_using_descriptor_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t descriptor_handle);
340 
341 /**
342  * @brief Reads the long characteristic descriptor using its handle. It will be returned in several blobs. For each blob, an le_characteristic_descriptor_event_t with type set to GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT will be generated and passed to the registered callback. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of read.
343  */
344 uint8_t gatt_client_read_long_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t  * descriptor);
345 uint8_t gatt_client_read_long_characteristic_descriptor_using_descriptor_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t descriptor_handle);
346 uint8_t gatt_client_read_long_characteristic_descriptor_using_descriptor_handle_with_offset(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t descriptor_handle, uint16_t offset);
347 
348 /**
349  * @brief Writes the characteristic descriptor using its handle. The gatt_complete_event_t with type set to GATT_EVENT_QUERY_COMPLETE, marks the end of write. The write is successfully performed, if the event's status field is set to 0.
350  */
351 uint8_t gatt_client_write_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t  * descriptor, uint16_t length, uint8_t  * data);
352 uint8_t gatt_client_write_characteristic_descriptor_using_descriptor_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t descriptor_handle, uint16_t length, uint8_t  * data);
353 uint8_t gatt_client_write_long_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t  * descriptor, uint16_t length, uint8_t  * data);
354 uint8_t gatt_client_write_long_characteristic_descriptor_using_descriptor_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t descriptor_handle, uint16_t length, uint8_t  * data);
355 uint8_t gatt_client_write_long_characteristic_descriptor_using_descriptor_handle_with_offset(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t descriptor_handle, uint16_t offset, uint16_t length, uint8_t  * data);
356 
357 /**
358  * @brief Writes the client characteristic configuration of the specified characteristic. It is used to subscribe for notifications or indications of the characteristic value. For notifications or indications specify: GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION resp. GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_INDICATION as configuration value.
359  */
360 uint8_t gatt_client_write_client_characteristic_configuration(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t * characteristic, uint16_t configuration);
361 
362 /**
363  * @brief Register for notifications and indications of a characteristic enabled by gatt_client_write_client_characteristic_configuration
364  * @param notification struct used to store registration
365  * @param packet_handler
366  * @param con_handle
367  * @param characteristic
368  */
369 void gatt_client_listen_for_characteristic_value_updates(gatt_client_notification_t * notification, btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, gatt_client_characteristic_t * characteristic);
370 
371 /**
372  * @brief Stop listening to characteristic value updates registered with gatt_client_listen_for_characteristic_value_updates
373  * @param notification struct used in gatt_client_listen_for_characteristic_value_updates
374  */
375 void gatt_client_stop_listening_for_characteristic_value_updates(gatt_client_notification_t * notification);
376 
377 /**
378  * @brief Requests GATT_EVENT_CAN_WRITE_WITHOUT_RESPONSE that guarantees a single successful gatt_client_write_value_of_characteristic_without_response
379  * @param packet_handler
380  * @param con_handle
381  * @returns status
382  */
383 uint8_t gatt_client_request_can_write_without_response_event(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
384 
385 /**
386  * @brief -> gatt complete event
387  */
388 uint8_t gatt_client_prepare_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t offset, uint16_t length, uint8_t * data);
389 
390 /**
391  * @brief -> gatt complete event
392  */
393 uint8_t gatt_client_execute_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
394 
395 /**
396  * @brief -> gatt complete event
397  */
398 uint8_t gatt_client_cancel_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
399 
400 /* API_END */
401 
402 // used by generated btstack_event.c
403 
404 void gatt_client_deserialize_service(const uint8_t *packet, int offset, gatt_client_service_t *service);
405 void gatt_client_deserialize_characteristic(const uint8_t * packet, int offset, gatt_client_characteristic_t * characteristic);
406 void gatt_client_deserialize_characteristic_descriptor(const uint8_t * packet, int offset, gatt_client_characteristic_descriptor_t * descriptor);
407 
408 #if defined __cplusplus
409 }
410 #endif
411 
412 #endif
413