xref: /btstack/src/ble/gatt_client.h (revision 7627a0deeabd72d5264a2cb546a1803d0bfada99)
1 /*
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37 
38 /**
39  * @title GATT Client
40  *
41  */
42 
43 #ifndef btstack_gatt_client_h
44 #define btstack_gatt_client_h
45 
46 #include "hci.h"
47 
48 #if defined __cplusplus
49 extern "C" {
50 #endif
51 
52 typedef enum {
53     P_READY,
54     P_W2_SEND_SERVICE_QUERY,
55     P_W4_SERVICE_QUERY_RESULT,
56     P_W2_SEND_SERVICE_WITH_UUID_QUERY,
57     P_W4_SERVICE_WITH_UUID_RESULT,
58 
59     P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY,
60     P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT,
61     P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY,
62     P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT,
63 
64     P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY,
65     P_W4_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT,
66 
67     P_W2_SEND_INCLUDED_SERVICE_QUERY,
68     P_W4_INCLUDED_SERVICE_QUERY_RESULT,
69     P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY,
70     P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT,
71 
72     P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY,
73     P_W4_READ_CHARACTERISTIC_VALUE_RESULT,
74 
75     P_W2_SEND_READ_BLOB_QUERY,
76     P_W4_READ_BLOB_RESULT,
77 
78     P_W2_SEND_READ_BY_TYPE_REQUEST,
79     P_W4_READ_BY_TYPE_RESPONSE,
80 
81     P_W2_SEND_READ_MULTIPLE_REQUEST,
82     P_W4_READ_MULTIPLE_RESPONSE,
83 
84     P_W2_SEND_WRITE_CHARACTERISTIC_VALUE,
85     P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT,
86 
87     P_W2_PREPARE_WRITE,
88     P_W4_PREPARE_WRITE_RESULT,
89     P_W2_PREPARE_RELIABLE_WRITE,
90     P_W4_PREPARE_RELIABLE_WRITE_RESULT,
91 
92     P_W2_EXECUTE_PREPARED_WRITE,
93     P_W4_EXECUTE_PREPARED_WRITE_RESULT,
94     P_W2_CANCEL_PREPARED_WRITE,
95     P_W4_CANCEL_PREPARED_WRITE_RESULT,
96     P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH,
97     P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT,
98 
99 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
100     P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY,
101     P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT,
102 #else
103     P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY,
104     P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT,
105 #endif
106     P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION,
107     P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT,
108 
109     P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY,
110     P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT,
111 
112     P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY,
113     P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT,
114 
115     P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR,
116     P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT,
117 
118     // all long writes use this
119     P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR,
120     P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT,
121     P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR,
122     P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT,
123 
124     // gatt reliable write API use this (manual version of the above)
125     P_W2_PREPARE_WRITE_SINGLE,
126     P_W4_PREPARE_WRITE_SINGLE_RESULT,
127 
128     P_W4_IDENTITY_RESOLVING,
129     P_W4_CMAC_READY,
130     P_W4_CMAC_RESULT,
131     P_W2_SEND_SIGNED_WRITE,
132     P_W4_SEND_SINGED_WRITE_DONE,
133 
134     P_W2_SDP_QUERY,
135     P_W4_SDP_QUERY,
136     P_W4_L2CAP_CONNECTION,
137 } gatt_client_state_t;
138 
139 
140 typedef enum{
141     SEND_MTU_EXCHANGE,
142     SENT_MTU_EXCHANGE,
143     MTU_EXCHANGED,
144     MTU_AUTO_EXCHANGE_DISABLED
145 } gatt_client_mtu_t;
146 
147 #ifdef ENABLE_GATT_OVER_EATT
148 typedef enum {
149     GATT_CLIENT_EATT_IDLE,
150     GATT_CLIENT_EATT_DISCOVER_GATT_SERVICE_W2_SEND,
151     GATT_CLIENT_EATT_DISCOVER_GATT_SERVICE_W4_DONE,
152     GATT_CLIENT_EATT_READ_SERVER_SUPPORTED_FEATURES_W2_SEND,
153     GATT_CLIENT_EATT_READ_SERVER_SUPPORTED_FEATURES_W4_DONE,
154     GATT_CLIENT_EATT_FIND_CLIENT_SUPPORTED_FEATURES_W2_SEND,
155     GATT_CLIENT_EATT_FIND_CLIENT_SUPPORTED_FEATURES_W4_DONE,
156     GATT_CLIENT_EATT_WRITE_ClIENT_SUPPORTED_FEATURES_W2_SEND,
157     GATT_CLIENT_EATT_WRITE_ClIENT_SUPPORTED_FEATURES_W4_DONE,
158     GATT_CLIENT_EATT_L2CAP_SETUP,
159     GATT_CLIENT_EATT_READY,
160 } gatt_client_eatt_state_t;
161 #endif
162 
163 typedef struct gatt_client{
164     btstack_linked_item_t    item;
165     // TODO: rename gatt_client_state -> state
166     gatt_client_state_t gatt_client_state;
167 
168     // user callback
169     btstack_packet_handler_t callback;
170 
171     // can write without response callback
172     btstack_packet_handler_t write_without_response_callback;
173 
174     // can write without response requests
175     btstack_linked_list_t write_without_response_requests;
176 
177     // regular gatt query requests
178     btstack_linked_list_t query_requests;
179 
180     hci_con_handle_t con_handle;
181 
182     att_bearer_type_t bearer_type;
183 
184 #ifdef ENABLE_GATT_OVER_CLASSIC
185     bd_addr_t addr;
186     uint16_t  l2cap_psm;
187     uint16_t  l2cap_cid;
188     btstack_context_callback_registration_t sdp_query_request;
189 #endif
190 
191 #ifdef ENABLE_GATT_OVER_EATT
192     gatt_client_eatt_state_t eatt_state;
193     btstack_linked_list_t eatt_clients;
194     uint8_t * eatt_storage_buffer;
195     uint16_t eatt_storage_size;
196     uint8_t  eatt_num_clients;
197     uint8_t  gatt_server_supported_features;
198     uint16_t gatt_service_start_group_handle;
199     uint16_t gatt_service_end_group_handle;
200     uint16_t gatt_client_supported_features_handle;
201 #endif
202 
203     uint16_t          mtu;
204     gatt_client_mtu_t mtu_state;
205 
206     uint16_t uuid16;
207     uint8_t  uuid128[16];
208 
209     uint16_t start_group_handle;
210     uint16_t end_group_handle;
211 
212     uint16_t query_start_handle;
213     uint16_t query_end_handle;
214 
215     uint8_t  characteristic_properties;
216     uint16_t characteristic_start_handle;
217 
218     uint16_t attribute_handle;
219     uint16_t attribute_offset;
220     uint16_t attribute_length;
221     uint8_t* attribute_value;
222 
223     // read multiple characteristic values
224     uint16_t    read_multiple_handle_count;
225     uint16_t  * read_multiple_handles;
226 
227     uint16_t client_characteristic_configuration_handle;
228     uint8_t  client_characteristic_configuration_value[2];
229 
230     uint8_t  filter_with_uuid;
231     uint8_t  send_confirmation;
232 
233     int      le_device_index;
234     uint8_t  cmac[8];
235 
236     btstack_timer_source_t gc_timeout;
237 
238     uint8_t  security_counter;
239     uint8_t  wait_for_authentication_complete;
240     uint8_t  pending_error_code;
241 
242     bool     reencryption_active;
243     uint8_t  reencryption_result;
244 
245     gap_security_level_t security_level;
246 
247 } gatt_client_t;
248 
249 typedef struct gatt_client_notification {
250     btstack_linked_item_t    item;
251     btstack_packet_handler_t callback;
252     hci_con_handle_t con_handle;
253     uint16_t attribute_handle;
254 } gatt_client_notification_t;
255 
256 /* API_START */
257 
258 typedef struct {
259     uint16_t start_group_handle;
260     uint16_t end_group_handle;
261     uint16_t uuid16;
262     uint8_t  uuid128[16];
263 } gatt_client_service_t;
264 
265 typedef struct {
266     uint16_t start_handle;
267     uint16_t value_handle;
268     uint16_t end_handle;
269     uint16_t properties;
270     uint16_t uuid16;
271     uint8_t  uuid128[16];
272 } gatt_client_characteristic_t;
273 
274 typedef struct {
275     uint16_t handle;
276     uint16_t uuid16;
277     uint8_t  uuid128[16];
278 } gatt_client_characteristic_descriptor_t;
279 
280 /**
281  * @brief Set up GATT client.
282  */
283 void gatt_client_init(void);
284 
285 /**
286  * @brief Set minimum required security level for GATT Client
287  * @note  The Bluetooth specification makes the GATT Server responsible to check for security.
288  *        This allows an attacker to spoof an existing device with a GATT Servers, but skip the authentication part.
289  *        If your application is exchanging sensitive data with a remote device, you would need to manually check
290  *        the security level before sending/receive such data.
291  *        With level > 0, the GATT Client triggers authentication for all GATT Requests and defers any exchange
292  *        until the required security level is established.
293  *        gatt_client_request_can_write_without_response_event does not trigger authentication
294  *        gatt_client_request_to_write_without_response does not trigger authentication
295  *  @pram level, default LEVEL_0 (no encryption required)
296  */
297 void gatt_client_set_required_security_level(gap_security_level_t level);
298 
299 /**
300  * @brief Connect to remote GATT Server over Classic (BR/EDR) Connection
301  *        GATT_EVENT_CONNECTED with status and con_handle for other API functions
302  *        is emitted on connection complete.
303  * @note requires ENABLE_GATT_OVER_CLASSIC.
304  * @param addr
305  * @return status
306  */
307 uint8_t gatt_client_classic_connect(btstack_packet_handler_t callback, bd_addr_t addr);
308 
309 /**
310  * @brief Disconnect o Classic (BR/EDR) connection to a remote GATT Server
311  * @note requires ENABLE_GATT_OVER_CLASSIC
312  * @param con_handle
313  * @return status
314  */
315 uint8_t gatt_client_classic_disconnect(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
316 
317 /**
318  * @brief Setup Enhanced LE Bearer with up to 5 channels on existing LE connection
319  * @param callback for GATT_EVENT_CONNECTED and GATT_EVENT_DISCONNECTED events
320  * @param con_handle
321  * @param num_channels
322  * @param storage_buffer for L2CAP connection
323  * @param storage_size
324  * @return
325  */
326 uint8_t gatt_client_le_enhanced_connect(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint8_t num_channels, uint8_t * storage_buffer, uint16_t storage_size);
327 
328 /**
329  * @brief MTU is available after the first query has completed. If status is equal to ERROR_CODE_SUCCESS, it returns the real value,
330  * otherwise the default value ATT_DEFAULT_MTU (see bluetooth.h).
331  * @param  con_handle
332  * @param  mtu
333  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
334  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
335  *                GATT_CLIENT_IN_WRONG_STATE                                if MTU is not exchanged and MTU auto-exchange is disabled
336  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
337  */
338 uint8_t gatt_client_get_mtu(hci_con_handle_t con_handle, uint16_t * mtu);
339 
340 /**
341  * @brief Sets whether a MTU Exchange Request shall be automatically send before the
342  * first attribute read request is send. Default is enabled.
343  * @param enabled
344  */
345 void gatt_client_mtu_enable_auto_negotiation(uint8_t enabled);
346 
347 /**
348  * @brief Sends a MTU Exchange Request, this allows for the client to exchange MTU
349  * when gatt_client_mtu_enable_auto_negotiation is disabled.
350  * @param  callback
351  * @param  con_handle
352  */
353 void gatt_client_send_mtu_negotiation(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
354 
355 /**
356  * @brief Returns 1 if the GATT client is ready to receive a query. It is used with daemon.
357  * @param  con_handle
358  * @return is_ready_status     0 - if no GATT client for con_handle is found, or is not ready, otherwise 1
359  */
360 int gatt_client_is_ready(hci_con_handle_t con_handle);
361 
362 /**
363  * @brief Discovers all primary services.
364  * For each found service a GATT_EVENT_SERVICE_QUERY_RESULT event will be emitted.
365  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
366  * @param  callback
367  * @param  con_handle
368  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
369  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
370  *                ERROR_CODE_SUCCESS         , if query is successfully registered
371  */
372 uint8_t gatt_client_discover_primary_services(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
373 
374 /**
375  * @brief Discovers all secondary services.
376  * For each found service a GATT_EVENT_SERVICE_QUERY_RESULT event will be emitted.
377  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
378  * @param  callback
379  * @param  con_handle
380  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
381  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
382  *                ERROR_CODE_SUCCESS         , if query is successfully registered
383  */
384 uint8_t gatt_client_discover_secondary_services(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
385 
386 /**
387  * @brief Discovers a specific primary service given its UUID. This service may exist multiple times.
388  * For each found service a GATT_EVENT_SERVICE_QUERY_RESULT event will be emitted.
389  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
390  * @param callback
391  * @param con_handle
392  * @param uuid16
393  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
394  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
395  *                ERROR_CODE_SUCCESS         , if query is successfully registered
396  */
397 uint8_t gatt_client_discover_primary_services_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t uuid16);
398 
399 /**
400  * @brief Discovers a specific primary service given its UUID. This service may exist multiple times.
401  * For each found service a GATT_EVENT_SERVICE_QUERY_RESULT event will be emitted.
402  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
403  * @param  callback
404  * @param  con_handle
405  * @param  uuid128
406  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
407  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
408  *                ERROR_CODE_SUCCESS         , if query is successfully registered
409  */
410 uint8_t gatt_client_discover_primary_services_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, const uint8_t * uuid128);
411 
412 /**
413  * @brief Finds included services within the specified service.
414  * For each found included service a GATT_EVENT_INCLUDED_SERVICE_QUERY_RESULT event will be emitted.
415  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
416  * Information about included service type (primary/secondary) can be retrieved either by sending
417  * an ATT find information request for the returned start group handle
418  * (returning the handle and the UUID for primary or secondary service) or by comparing the service
419  * to the list of all primary services.
420  * @param  callback
421  * @param  con_handle
422  * @param  service
423  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
424  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
425  *                ERROR_CODE_SUCCESS         , if query is successfully registered
426  */
427 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);
428 
429 /**
430  * @brief Discovers all characteristics within the specified service.
431  * For each found characteristic a GATT_EVENT_CHARACTERISTIC_QUERY_RESULT event will be emited.
432  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
433  * @param  callback
434  * @param  con_handle
435  * @param  service
436  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
437  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
438  *                ERROR_CODE_SUCCESS         , if query is successfully registered
439  */
440 uint8_t gatt_client_discover_characteristics_for_service(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t * service);
441 
442 /**
443  * @brief The following four functions are used to discover all characteristics within
444  * the specified service or handle range, and return those that match the given UUID.
445  *
446  * For each found characteristic a GATT_EVENT_CHARACTERISTIC_QUERY_RESULT event will emitted.
447  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
448  * @param  callback
449  * @param  con_handle
450  * @param  start_handle
451  * @param  end_handle
452  * @param  uuid16
453  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
454  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
455  *                ERROR_CODE_SUCCESS         , if query is successfully registered
456  */
457 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);
458 
459 /**
460  * @brief The following four functions are used to discover all characteristics within the
461  * specified service or handle range, and return those that match the given UUID.
462  * For each found characteristic a GATT_EVENT_CHARACTERISTIC_QUERY_RESULT event will emitted.
463  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
464  * @param  callback
465  * @param  con_handle
466  * @param  start_handle
467  * @param  end_handle
468  * @param  uuid128
469  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
470  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
471  *                ERROR_CODE_SUCCESS         , if query is successfully registered
472  */
473 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, const uint8_t * uuid128);
474 
475 /**
476  * @brief The following four functions are used to discover all characteristics within the
477  * specified service or handle range, and return those that match the given UUID.
478  * For each found characteristic a GATT_EVENT_CHARACTERISTIC_QUERY_RESULT event will emitted.
479  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
480  * @param  callback
481  * @param  con_handle
482  * @param  service
483  * @param  uuid16
484  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
485  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
486  *                ERROR_CODE_SUCCESS         , if query is successfully registered
487  */
488 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);
489 
490 /**
491  * @brief The following four functions are used to discover all characteristics within the
492  * specified service or handle range, and return those that match the given UUID.
493  * For each found characteristic a GATT_EVENT_CHARACTERISTIC_QUERY_RESULT event will emitted.
494  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
495  * @param  callback
496  * @param  con_handle
497  * @param  service
498  * @param  uuid128
499  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
500  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
501  *                ERROR_CODE_SUCCESS         , if query is successfully registered
502  */
503 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, const uint8_t * uuid128);
504 
505 /**
506  * @brief Discovers attribute handle and UUID of a characteristic descriptor within the specified characteristic.
507  * For each found descriptor a GATT_EVENT_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT event will be emitted.
508  *
509  * The GATT_EVENT_QUERY_COMPLETE event marks the end of discovery.
510  * @param  callback
511  * @param  con_handle
512  * @param  characteristic
513  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
514  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
515  *                ERROR_CODE_SUCCESS         , if query is successfully registered
516  */
517 uint8_t gatt_client_discover_characteristic_descriptors(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t * characteristic);
518 
519 /**
520  * @brief Reads the characteristic value using the characteristic's value handle.
521  * If the characteristic value is found a GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT event will be emitted.
522  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
523  * @param  callback
524  * @param  con_handle
525  * @param  characteristic
526  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
527  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
528  *                ERROR_CODE_SUCCESS         , if query is successfully registered
529  */
530 uint8_t gatt_client_read_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t * characteristic);
531 
532 /**
533  * @brief Reads the characteristic value using the characteristic's value handle.
534  * If the characteristic value is found a GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT event will be emitted.
535  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
536  * @param  callback
537  * @param  con_handle
538  * @param  value_handle
539  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
540  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
541  *                ERROR_CODE_SUCCESS         , if query is successfully registered
542  */
543 uint8_t gatt_client_read_value_of_characteristic_using_value_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t value_handle);
544 
545 /**
546  * @brief Reads the characteric value of all characteristics with the uuid.
547  * For each characteristic value found a GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT event will be emitted.
548  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
549  * @param  callback
550  * @param  con_handle
551  * @param  start_handle
552  * @param  end_handle
553  * @param  uuid16
554  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
555  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
556  *                ERROR_CODE_SUCCESS         , if query is successfully registered
557  */
558 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);
559 
560 /**
561  * @brief Reads the characteric value of all characteristics with the uuid.
562  * For each characteristic value found a GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT event will be emitted.
563  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
564  * @param  callback
565  * @param  con_handle
566  * @param  start_handle
567  * @param  end_handle
568  * @param  uuid128
569  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
570  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
571  *                ERROR_CODE_SUCCESS         , if query is successfully registered
572  */
573 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, const uint8_t * uuid128);
574 
575 /**
576  * @brief Reads the long characteristic value using the characteristic's value handle.
577  * The value will be returned in several blobs.
578  * For each blob, a GATT_EVENT_LONG_CHARACTERISTIC_VALUE_QUERY_RESULT event with updated value offset will be emitted.
579  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
580  * @param  callback
581  * @param  con_handle
582  * @param  characteristic
583  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
584  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
585  *                ERROR_CODE_SUCCESS         , if query is successfully registered
586  */
587 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);
588 
589 /**
590  * @brief Reads the long characteristic value using the characteristic's value handle.
591  * The value will be returned in several blobs.
592  * For each blob, a GATT_EVENT_LONG_CHARACTERISTIC_VALUE_QUERY_RESULT event with updated value offset will be emitted.
593  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
594  * @param  callback
595  * @param  con_handle
596  * @param  value_handle
597  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
598  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
599  *                ERROR_CODE_SUCCESS         , if query is successfully registered
600  */
601 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 value_handle);
602 
603 /**
604  * @brief Reads the long characteristic value using the characteristic's value handle.
605  * The value will be returned in several blobs.
606  * For each blob, a GATT_EVENT_LONG_CHARACTERISTIC_VALUE_QUERY_RESULT event with updated value offset will be emitted.
607  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
608  * @param  callback
609  * @param  con_handle
610  * @param  value_handle
611  * @param  offset
612  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
613  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
614  *                ERROR_CODE_SUCCESS         , if query is successfully registered
615  */
616 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 value_handle, uint16_t offset);
617 
618 /*
619  * @brief Read multiple characteristic values.
620  * The all results are emitted via single GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT event,
621  * followed by the GATT_EVENT_QUERY_COMPLETE event, which marks the end of read.
622  * @param  callback
623  * @param  con_handle
624  * @param  num_value_handles
625  * @param  value_handles list of handles
626  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
627  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
628  *                ERROR_CODE_SUCCESS         , if query is successfully registered
629  */
630 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);
631 
632 /**
633  * @brief Writes the characteristic value using the characteristic's value handle without
634  * an acknowledgment that the write was successfully performed.
635  * @param  con_handle
636  * @param  value_handle
637  * @param  value_length
638  * @param  value is copied on success and does not need to be retained
639  * @return status BTSTACK_MEMORY_ALLOC_FAILED, if no GATT client for con_handle is found
640  *                GATT_CLIENT_IN_WRONG_STATE , if GATT client is not ready
641  *                BTSTACK_ACL_BUFFERS_FULL   , if L2CAP cannot send, there are no free ACL slots
642  *                ERROR_CODE_SUCCESS         , if query is successfully registered
643  */
644 uint8_t gatt_client_write_value_of_characteristic_without_response(hci_con_handle_t con_handle, uint16_t value_handle, uint16_t value_length, uint8_t * value);
645 
646 /**
647  * @brief Writes the authenticated characteristic value using the characteristic's value handle
648  * without an acknowledgment that the write was successfully performed.
649  * @note GATT_EVENT_QUERY_COMPLETE is emitted with ATT_ERROR_SUCCESS for success,
650  * or ATT_ERROR_BONDING_INFORMATION_MISSING if there is no bonding information stored.
651  * @param  callback
652  * @param  con_handle
653  * @param  value_handle
654  * @param  message_len
655  * @param  message is not copied, make sure memory is accessible until write is done
656  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
657  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
658  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
659  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
660  */
661 uint8_t gatt_client_signed_write_without_response(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t value_handle, uint16_t message_len, uint8_t * message);
662 
663 /**
664  * @brief Writes the characteristic value using the characteristic's value handle.
665  * The GATT_EVENT_QUERY_COMPLETE event marks the end of write.
666  * The write is successfully performed, if the event's att_status field is set to
667  * ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
668  * @param  callback
669  * @param  con_handle
670  * @param  value_handle
671  * @param  value_length
672  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
673  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
674  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
675  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
676  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
677  */
678 uint8_t gatt_client_write_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t value_handle, uint16_t value_length, uint8_t * value);
679 
680 /**
681  * @brief Writes the characteristic value using the characteristic's value handle.
682  * The GATT_EVENT_QUERY_COMPLETE event marks the end of write.
683  * The write is successfully performed if the event's att_status field is set to ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
684  * @param  callback
685  * @param  con_handle
686  * @param  value_handle
687  * @param  value_length
688  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
689  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
690  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
691  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
692  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
693  */
694 uint8_t gatt_client_write_long_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t value_handle, uint16_t value_length, uint8_t * value);
695 
696 /**
697  * @brief Writes the characteristic value using the characteristic's value handle.
698  * The GATT_EVENT_QUERY_COMPLETE event marks the end of write.
699  * The write is successfully performed if the event's att_status field is set to ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
700  * @param  callback
701  * @param  con_handle
702  * @param  value_handle
703  * @param  offset of value
704  * @param  value_length
705  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
706  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
707  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
708  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
709  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
710  */
711 uint8_t gatt_client_write_long_value_of_characteristic_with_offset(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t value_handle, uint16_t offset, uint16_t value_length, uint8_t * value);
712 
713 /**
714  * @brief Writes of the long characteristic value using the characteristic's value handle.
715  * It uses server response to validate that the write was correctly received.
716  * The GATT_EVENT_QUERY_COMPLETE EVENT marks the end of write.
717  * The write is successfully performed, if the event's att_status field is set to ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
718  * @param  callback
719  * @param  con_handle
720  * @param  value_handle
721  * @param  value_length
722  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
723  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
724  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
725  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
726  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
727  */
728 uint8_t gatt_client_reliable_write_long_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t value_handle, uint16_t value_length, uint8_t * value);
729 
730 /**
731  * @brief Reads the characteristic descriptor using its handle.
732  * If the characteristic descriptor is found, a GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT event will be emitted.
733  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
734  * @param  callback
735  * @param  con_handle
736  * @param  descriptor
737  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
738  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
739  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
740  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
741  */
742 uint8_t gatt_client_read_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t * descriptor);
743 
744 /**
745  * @brief Reads the characteristic descriptor using its handle.
746  * If the characteristic descriptor is found, a GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT event will be emitted.
747  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
748  * @param  callback
749  * @param  con_handle
750  * @param  descriptor
751  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
752  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
753  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
754  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
755  */
756 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);
757 
758 /**
759  * @brief Reads the long characteristic descriptor using its handle. It will be returned in several blobs.
760  * For each blob, a GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT event will be emitted.
761  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
762  * @param  callback
763  * @param  con_handle
764  * @param  descriptor
765  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
766  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
767  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
768  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
769  */
770 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);
771 
772 /**
773  * @brief Reads the long characteristic descriptor using its handle. It will be returned in several blobs.
774  * For each blob, a GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT event will be emitted.
775  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
776  * @param  callback
777  * @param  con_handle
778  * @param  descriptor_handle
779  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
780  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
781  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
782  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
783  */
784 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);
785 
786 /**
787  * @brief Reads the long characteristic descriptor using its handle. It will be returned in several blobs.
788  * For each blob, a GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT event will be emitted.
789  * The GATT_EVENT_QUERY_COMPLETE event marks the end of read.
790  * @param  callback
791  * @param  con_handle
792  * @param  descriptor_handle
793  * @param  offset
794  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
795  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
796  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
797  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
798  */
799 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);
800 
801 /**
802  * @brief Writes the characteristic descriptor using its handle.
803  * The GATT_EVENT_QUERY_COMPLETE event marks the end of write.
804  * The write is successfully performed if the event's att_status field is set to ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
805  * @param  callback
806  * @param  con_handle
807  * @param  descriptor
808  * @param  value_length
809  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
810  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
811  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
812  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
813  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
814  */
815 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 value_length, uint8_t * value);
816 
817 /**
818  * @brief Writes the characteristic descriptor using its handle.
819  * The GATT_EVENT_QUERY_COMPLETE event marks the end of write.
820  * The write is successfully performed if the event's att_status field is set to ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
821  * @param  callback
822  * @param  con_handle
823  * @param  descriptor_handle
824  * @param  value_length
825  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
826  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
827  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
828  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
829  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
830  */
831 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 value_length, uint8_t * value);
832 
833 /**
834  * @brief Writes the characteristic descriptor using its handle.
835  * The GATT_EVENT_QUERY_COMPLETE event marks the end of write.
836  * The write is successfully performed if the event's att_status field is set to ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
837  * @param  callback
838  * @param  con_handle
839  * @param  descriptor
840  * @param  value_length
841  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
842  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
843  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
844  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
845  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
846  */
847 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 value_length, uint8_t * value);
848 
849 /**
850  * @brief Writes the characteristic descriptor using its handle.
851  * The GATT_EVENT_QUERY_COMPLETE event marks the end of write.
852  * The write is successfully performed if the event's att_status field is set to ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
853  * @param  callback
854  * @param  con_handle
855  * @param  descriptor_handle
856  * @param  value_length
857  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
858  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
859  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
860  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
861  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
862  */
863 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 value_length, uint8_t * value);
864 
865 /**
866  * @brief Writes the characteristic descriptor using its handle.
867  * The GATT_EVENT_QUERY_COMPLETE event marks the end of write.
868  * The write is successfully performed if the event's att_status field is set to ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
869  * @param  callback
870  * @param  con_handle
871  * @param  descriptor_handle
872  * @param  offset of value
873  * @param  value_length
874  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
875  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
876  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
877  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
878  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
879  */
880 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 value_length, uint8_t * value);
881 
882 /**
883  * @brief Writes the client characteristic configuration of the specified characteristic.
884  * It is used to subscribe for notifications or indications of the characteristic value.
885  * For notifications or indications specify: GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION
886  * resp. GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_INDICATION as configuration value.
887  * The GATT_EVENT_QUERY_COMPLETE event marks the end of write.
888  * The write is successfully performed if the event's att_status field is set to ATT_ERROR_SUCCESS (see bluetooth.h for ATT_ERROR codes).
889  * @param  callback
890  * @param  con_handle
891  * @param  characteristic
892  * @param  configuration                                                    GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION, GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_INDICATION
893  * @return status ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER                  if no HCI connection for con_handle is found
894  *                BTSTACK_MEMORY_ALLOC_FAILED                               if no GATT client for con_handle could be allocated
895  *                GATT_CLIENT_IN_WRONG_STATE                                if GATT client is not ready
896  *                GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED     if configuring notification, but characteristic has no notification property set
897  *                GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED       if configuring indication, but characteristic has no indication property set
898  *                ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE         if configuration is invalid
899  *                ERROR_CODE_SUCCESS                                        if query is successfully registered
900  */
901 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);
902 
903 /**
904  * @brief Register for notifications and indications of a characteristic enabled by
905  * the gatt_client_write_client_characteristic_configuration function.
906  * @param notification struct used to store registration
907  * @param callback
908  * @param con_handle or GATT_CLIENT_ANY_CONNECTION to receive updates from all connected devices
909  * @param characteristic or NULL to receive updates for all characteristics
910  */
911 void gatt_client_listen_for_characteristic_value_updates(gatt_client_notification_t * notification, btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t * characteristic);
912 
913 /**
914  * @brief Stop listening to characteristic value updates registered with
915  * the gatt_client_listen_for_characteristic_value_updates function.
916  * @param notification struct used in gatt_client_listen_for_characteristic_value_updates
917  */
918 void gatt_client_stop_listening_for_characteristic_value_updates(gatt_client_notification_t * notification);
919 
920 /**
921  * @brief Transactional write. It can be called as many times as it is needed to write the characteristics within the same transaction.
922  * Call the gatt_client_execute_write function to commit the transaction.
923  * @param  callback
924  * @param  con_handle
925  * @param  attribute_handle
926  * @param  offset of value
927  * @param  value_length
928  * @param  value is not copied, make sure memory is accessible until write is done, i.e. GATT_EVENT_QUERY_COMPLETE is received
929  */
930 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 value_length, uint8_t * value);
931 
932 /**
933  * @brief Commit transactional write. GATT_EVENT_QUERY_COMPLETE is received.
934  * @param  callback
935  * @param  con_handle
936  * @return status
937  */
938 uint8_t gatt_client_execute_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
939 
940 /**
941  * @brief Abort transactional write. GATT_EVENT_QUERY_COMPLETE is received.
942  * @param  callback
943  * @param  con_handle
944  * @return status
945  */
946 uint8_t gatt_client_cancel_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
947 
948 /**
949  * @brief Request callback when regular gatt query can be sent
950  * @note callback might happen during call to this function
951  * @param callback_registration to point to callback function and context information
952  * @param con_handle
953  * @return ERROR_CODE_SUCCESS if ok, ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER if handle unknown, and ERROR_CODE_COMMAND_DISALLOWED if callback already registered
954  */
955 uint8_t gatt_client_request_to_send_gatt_query(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle);
956 
957 /**
958  * @brief Request callback when writing characteristic value without response is possible
959  * @note callback might happen during call to this function
960  * @param callback_registration to point to callback function and context information
961  * @param con_handle
962  * @return ERROR_CODE_SUCCESS if ok, ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER if handle unknown, and ERROR_CODE_COMMAND_DISALLOWED if callback already registered
963  */
964 uint8_t gatt_client_request_to_write_without_response(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle);
965 
966 
967 // the following functions are marked as deprecated and will be removed eventually
968 /**
969  * @brief Requests GATT_EVENT_CAN_WRITE_WITHOUT_RESPONSE that guarantees
970  * a single successful gatt_client_write_value_of_characteristic_without_response call.
971  * @deprecated please use gatt_client_request_to_write_without_response instead
972  * @param  callback
973  * @param  con_handle
974  * @return status
975  */
976 uint8_t gatt_client_request_can_write_without_response_event(btstack_packet_handler_t callback, hci_con_handle_t con_handle);
977 
978 
979 /* API_END */
980 
981 // used by generated btstack_event.c
982 
983 void gatt_client_deserialize_service(const uint8_t *packet, int offset, gatt_client_service_t * service);
984 void gatt_client_deserialize_characteristic(const uint8_t * packet, int offset, gatt_client_characteristic_t * characteristic);
985 void gatt_client_deserialize_characteristic_descriptor(const uint8_t * packet, int offset, gatt_client_characteristic_descriptor_t * descriptor);
986 
987 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
988 void gatt_client_att_packet_handler_fuzz(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size);
989 uint8_t gatt_client_get_client(hci_con_handle_t con_handle, gatt_client_t ** gatt_client);
990 #endif
991 
992 #if defined __cplusplus
993 }
994 #endif
995 
996 #endif
997