xref: /btstack/src/ble/gatt_client.c (revision 1450cdc6346bbe51244000163e2d28698dd69a8c)
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 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__ "gatt_client.c"
39 
40 #include <stdint.h>
41 #include <string.h>
42 #include <stddef.h>
43 
44 #include "btstack_config.h"
45 
46 #include "ble/att_dispatch.h"
47 #include "ble/att_db.h"
48 #include "ble/gatt_client.h"
49 #include "ble/le_device_db.h"
50 #include "ble/sm.h"
51 #include "btstack_debug.h"
52 #include "btstack_event.h"
53 #include "btstack_memory.h"
54 #include "btstack_run_loop.h"
55 #include "btstack_util.h"
56 #include "hci.h"
57 #include "hci_dump.h"
58 #include "l2cap.h"
59 #include "classic/sdp_client.h"
60 #include "bluetooth_gatt.h"
61 #include "bluetooth_sdp.h"
62 #include "classic/sdp_util.h"
63 
64 static btstack_linked_list_t gatt_client_connections;
65 static btstack_linked_list_t gatt_client_value_listeners;
66 static btstack_packet_callback_registration_t hci_event_callback_registration;
67 static btstack_packet_callback_registration_t sm_event_callback_registration;
68 
69 // GATT Client Configuration
70 static bool                 gatt_client_mtu_exchange_enabled;
71 static gap_security_level_t gatt_client_required_security_level;
72 
73 static void gatt_client_att_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size);
74 static void gatt_client_event_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
75 static void gatt_client_report_error_if_pending(gatt_client_t *gatt_client, uint8_t att_error_code);
76 
77 #ifdef ENABLE_LE_SIGNED_WRITE
78 static void att_signed_write_handle_cmac_result(uint8_t hash[8]);
79 #endif
80 
81 void gatt_client_init(void){
82     gatt_client_connections = NULL;
83 
84     // default configuration
85     gatt_client_mtu_exchange_enabled    = true;
86     gatt_client_required_security_level = LEVEL_0;
87 
88     // register for HCI Events
89     hci_event_callback_registration.callback = &gatt_client_event_packet_handler;
90     hci_add_event_handler(&hci_event_callback_registration);
91 
92     // register for SM Events
93     sm_event_callback_registration.callback = &gatt_client_event_packet_handler;
94     sm_add_event_handler(&sm_event_callback_registration);
95 
96     // and ATT Client PDUs
97     att_dispatch_register_client(gatt_client_att_packet_handler);
98 }
99 
100 void gatt_client_set_required_security_level(gap_security_level_t level){
101     gatt_client_required_security_level = level;
102 }
103 
104 static gatt_client_t * gatt_client_for_timer(btstack_timer_source_t * ts){
105     btstack_linked_list_iterator_t it;
106     btstack_linked_list_iterator_init(&it, &gatt_client_connections);
107     while (btstack_linked_list_iterator_has_next(&it)){
108         gatt_client_t * gatt_client = (gatt_client_t *) btstack_linked_list_iterator_next(&it);
109         if (&gatt_client->gc_timeout == ts) {
110             return gatt_client;
111         }
112     }
113     return NULL;
114 }
115 
116 static void gatt_client_timeout_handler(btstack_timer_source_t * timer){
117     gatt_client_t * gatt_client = gatt_client_for_timer(timer);
118     if (gatt_client == NULL) return;
119     log_info("GATT client timeout handle, handle 0x%02x", gatt_client->con_handle);
120     gatt_client_report_error_if_pending(gatt_client, ATT_ERROR_TIMEOUT);
121 }
122 
123 static void gatt_client_timeout_start(gatt_client_t * gatt_client){
124     log_info("GATT client timeout start, handle 0x%02x", gatt_client->con_handle);
125     btstack_run_loop_remove_timer(&gatt_client->gc_timeout);
126     btstack_run_loop_set_timer_handler(&gatt_client->gc_timeout, gatt_client_timeout_handler);
127     btstack_run_loop_set_timer(&gatt_client->gc_timeout, 30000); // 30 seconds sm timeout
128     btstack_run_loop_add_timer(&gatt_client->gc_timeout);
129 }
130 
131 static void gatt_client_timeout_stop(gatt_client_t * gatt_client){
132     log_info("GATT client timeout stop, handle 0x%02x", gatt_client->con_handle);
133     btstack_run_loop_remove_timer(&gatt_client->gc_timeout);
134 }
135 
136 static gap_security_level_t gatt_client_le_security_level_for_connection(hci_con_handle_t con_handle){
137     uint8_t encryption_key_size = gap_encryption_key_size(con_handle);
138     if (encryption_key_size == 0) return LEVEL_0;
139 
140     bool authenticated = gap_authenticated(con_handle);
141     if (!authenticated) return LEVEL_2;
142 
143     return encryption_key_size == 16 ? LEVEL_4 : LEVEL_3;
144 }
145 
146 static gatt_client_t * gatt_client_get_context_for_handle(uint16_t handle){
147     btstack_linked_item_t *it;
148     for (it = (btstack_linked_item_t *) gatt_client_connections; it != NULL; it = it->next){
149         gatt_client_t * gatt_client = (gatt_client_t *) it;
150         if (gatt_client->con_handle == handle){
151             return gatt_client;
152         }
153     }
154     return NULL;
155 }
156 
157 
158 // @return gatt_client context
159 // returns existing one, or tries to setup new one
160 static uint8_t gatt_client_provide_context_for_handle(hci_con_handle_t con_handle, gatt_client_t ** out_gatt_client){
161     gatt_client_t * gatt_client = gatt_client_get_context_for_handle(con_handle);
162 
163     if (gatt_client != NULL){
164         *out_gatt_client = gatt_client;
165         return ERROR_CODE_SUCCESS;
166     }
167 
168     // bail if no such hci connection
169     hci_connection_t * hci_connection = hci_connection_for_handle(con_handle);
170     if (hci_connection == NULL){
171         log_error("No connection for handle 0x%04x", con_handle);
172         *out_gatt_client = NULL;
173         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
174     }
175 
176     gatt_client = btstack_memory_gatt_client_get();
177     if (gatt_client == NULL){
178         *out_gatt_client = NULL;
179         return ERROR_CODE_MEMORY_CAPACITY_EXCEEDED;
180     }
181     // init state
182     gatt_client->con_handle = con_handle;
183     gatt_client->mtu = ATT_DEFAULT_MTU;
184     gatt_client->security_level = gatt_client_le_security_level_for_connection(con_handle);
185     if (gatt_client_mtu_exchange_enabled){
186         gatt_client->mtu_state = SEND_MTU_EXCHANGE;
187     } else {
188         gatt_client->mtu_state = MTU_AUTO_EXCHANGE_DISABLED;
189     }
190     gatt_client->gatt_client_state = P_READY;
191     btstack_linked_list_add(&gatt_client_connections, (btstack_linked_item_t*)gatt_client);
192 
193     // get unenhanced att bearer state
194     if (hci_connection->att_connection.mtu_exchanged){
195         gatt_client->mtu = hci_connection->att_connection.mtu;
196         gatt_client->mtu_state = MTU_EXCHANGED;
197     }
198     *out_gatt_client = gatt_client;
199     return ERROR_CODE_SUCCESS;
200 }
201 
202 static uint8_t gatt_client_provide_context_for_handle_and_start_timer(hci_con_handle_t con_handle, gatt_client_t ** out_gatt_client){
203     uint8_t status = gatt_client_provide_context_for_handle(con_handle, out_gatt_client);
204     if (status != ERROR_CODE_SUCCESS){
205         return status;
206     }
207     gatt_client_timeout_start(*out_gatt_client);
208     return status;
209 }
210 
211 static bool is_ready(gatt_client_t * gatt_client){
212     return gatt_client->gatt_client_state == P_READY;
213 }
214 
215 int gatt_client_is_ready(hci_con_handle_t con_handle){
216     gatt_client_t * gatt_client;
217     uint8_t status = gatt_client_provide_context_for_handle(con_handle, &gatt_client);
218     if (status != ERROR_CODE_SUCCESS){
219         return 0;
220     }
221     return is_ready(gatt_client) ? 1 : 0;
222 }
223 
224 void gatt_client_mtu_enable_auto_negotiation(uint8_t enabled){
225     gatt_client_mtu_exchange_enabled = enabled != 0;
226 }
227 
228 uint8_t gatt_client_get_mtu(hci_con_handle_t con_handle, uint16_t * mtu){
229     gatt_client_t * gatt_client;
230     uint8_t status = gatt_client_provide_context_for_handle(con_handle, &gatt_client);
231     if (status != ERROR_CODE_SUCCESS){
232         return status;
233     }
234 
235     if ((gatt_client->mtu_state == MTU_EXCHANGED) || (gatt_client->mtu_state == MTU_AUTO_EXCHANGE_DISABLED)){
236         *mtu = gatt_client->mtu;
237         return ERROR_CODE_SUCCESS;
238     }
239     *mtu = ATT_DEFAULT_MTU;
240     return GATT_CLIENT_IN_WRONG_STATE;
241 }
242 
243 // precondition: can_send_packet_now == TRUE
244 static uint8_t gatt_client_send(gatt_client_t * gatt_client, uint16_t len){
245     return l2cap_send_prepared_connectionless(gatt_client->con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, len);
246 }
247 
248 // precondition: can_send_packet_now == TRUE
249 static uint8_t att_confirmation(gatt_client_t * gatt_client) {
250     l2cap_reserve_packet_buffer();
251 
252     uint8_t * request = l2cap_get_outgoing_buffer();
253     request[0] = ATT_HANDLE_VALUE_CONFIRMATION;
254 
255     return gatt_client_send(gatt_client, 1);
256 }
257 
258 // precondition: can_send_packet_now == TRUE
259 static uint8_t att_find_information_request(gatt_client_t *gatt_client, uint8_t request_type, uint16_t start_handle,
260                                             uint16_t end_handle) {
261     l2cap_reserve_packet_buffer();
262     uint8_t * request = l2cap_get_outgoing_buffer();
263 
264     request[0] = request_type;
265     little_endian_store_16(request, 1, start_handle);
266     little_endian_store_16(request, 3, end_handle);
267 
268     return gatt_client_send(gatt_client, 5);
269 }
270 
271 // precondition: can_send_packet_now == TRUE
272 static uint8_t
273 att_find_by_type_value_request(gatt_client_t *gatt_client, uint8_t request_type, uint16_t attribute_group_type,
274                                uint16_t start_handle, uint16_t end_handle, uint8_t *value, uint16_t value_size) {
275     l2cap_reserve_packet_buffer();
276     uint8_t * request = l2cap_get_outgoing_buffer();
277 
278     request[0] = request_type;
279     little_endian_store_16(request, 1, start_handle);
280     little_endian_store_16(request, 3, end_handle);
281     little_endian_store_16(request, 5, attribute_group_type);
282     (void)memcpy(&request[7], value, value_size);
283 
284     return gatt_client_send(gatt_client, 7u + value_size);
285 }
286 
287 // precondition: can_send_packet_now == TRUE
288 static uint8_t
289 att_read_by_type_or_group_request_for_uuid16(gatt_client_t *gatt_client, uint8_t request_type, uint16_t uuid16,
290                                              uint16_t start_handle, uint16_t end_handle) {
291     l2cap_reserve_packet_buffer();
292     uint8_t * request = l2cap_get_outgoing_buffer();
293 
294     request[0] = request_type;
295     little_endian_store_16(request, 1, start_handle);
296     little_endian_store_16(request, 3, end_handle);
297     little_endian_store_16(request, 5, uuid16);
298 
299     return gatt_client_send(gatt_client, 7);
300 }
301 
302 // precondition: can_send_packet_now == TRUE
303 static uint8_t
304 att_read_by_type_or_group_request_for_uuid128(gatt_client_t *gatt_client, uint8_t request_type, const uint8_t *uuid128,
305                                               uint16_t start_handle, uint16_t end_handle) {
306     l2cap_reserve_packet_buffer();
307     uint8_t * request = l2cap_get_outgoing_buffer();
308 
309     request[0] = request_type;
310     little_endian_store_16(request, 1, start_handle);
311     little_endian_store_16(request, 3, end_handle);
312     reverse_128(uuid128, &request[5]);
313 
314     return gatt_client_send(gatt_client, 21);
315 }
316 
317 // precondition: can_send_packet_now == TRUE
318 static uint8_t att_read_request(gatt_client_t *gatt_client, uint8_t request_type, uint16_t attribute_handle) {
319     l2cap_reserve_packet_buffer();
320     uint8_t * request = l2cap_get_outgoing_buffer();
321 
322     request[0] = request_type;
323     little_endian_store_16(request, 1, attribute_handle);
324 
325     return gatt_client_send(gatt_client, 3);
326 }
327 
328 // precondition: can_send_packet_now == TRUE
329 static uint8_t att_read_blob_request(gatt_client_t *gatt_client, uint8_t request_type, uint16_t attribute_handle,
330                                      uint16_t value_offset) {
331     l2cap_reserve_packet_buffer();
332     uint8_t * request = l2cap_get_outgoing_buffer();
333     request[0] = request_type;
334     little_endian_store_16(request, 1, attribute_handle);
335     little_endian_store_16(request, 3, value_offset);
336 
337     return gatt_client_send(gatt_client, 5);
338 }
339 
340 static uint8_t
341 att_read_multiple_request(gatt_client_t *gatt_client, uint16_t num_value_handles, uint16_t *value_handles) {
342     l2cap_reserve_packet_buffer();
343     uint8_t * request = l2cap_get_outgoing_buffer();
344     request[0] = ATT_READ_MULTIPLE_REQUEST;
345     int i;
346     int offset = 1;
347     for (i=0;i<num_value_handles;i++){
348         little_endian_store_16(request, offset, value_handles[i]);
349         offset += 2;
350     }
351 
352     return gatt_client_send(gatt_client, offset);
353 }
354 
355 #ifdef ENABLE_LE_SIGNED_WRITE
356 // precondition: can_send_packet_now == TRUE
357 static uint8_t att_signed_write_request(gatt_client_t *gatt_client, uint16_t request_type, uint16_t attribute_handle,
358                                         uint16_t value_length, uint8_t *value, uint32_t sign_counter, uint8_t sgn[8]) {
359     l2cap_reserve_packet_buffer();
360     uint8_t * request = l2cap_get_outgoing_buffer();
361     request[0] = request_type;
362     little_endian_store_16(request, 1, attribute_handle);
363     (void)memcpy(&request[3], value, value_length);
364     little_endian_store_32(request, 3 + value_length, sign_counter);
365     reverse_64(sgn, &request[3 + value_length + 4]);
366 
367     return gatt_client_send(gatt_client, 3 + value_length + 12);
368 }
369 #endif
370 
371 // precondition: can_send_packet_now == TRUE
372 static uint8_t
373 att_write_request(gatt_client_t *gatt_client, uint8_t request_type, uint16_t attribute_handle, uint16_t value_length,
374                   uint8_t *value) {
375     l2cap_reserve_packet_buffer();
376     uint8_t * request = l2cap_get_outgoing_buffer();
377     request[0] = request_type;
378     little_endian_store_16(request, 1, attribute_handle);
379     (void)memcpy(&request[3], value, value_length);
380 
381     return gatt_client_send(gatt_client, 3u + value_length);
382 }
383 
384 // precondition: can_send_packet_now == TRUE
385 static uint8_t att_execute_write_request(gatt_client_t *gatt_client, uint8_t request_type, uint8_t execute_write) {
386     l2cap_reserve_packet_buffer();
387     uint8_t * request = l2cap_get_outgoing_buffer();
388     request[0] = request_type;
389     request[1] = execute_write;
390 
391     return gatt_client_send(gatt_client, 2);
392 }
393 
394 // precondition: can_send_packet_now == TRUE
395 static uint8_t att_prepare_write_request(gatt_client_t *gatt_client, uint8_t request_type, uint16_t attribute_handle,
396                                          uint16_t value_offset, uint16_t blob_length, uint8_t *value) {
397     l2cap_reserve_packet_buffer();
398     uint8_t * request = l2cap_get_outgoing_buffer();
399     request[0] = request_type;
400     little_endian_store_16(request, 1, attribute_handle);
401     little_endian_store_16(request, 3, value_offset);
402     (void)memcpy(&request[5], &value[value_offset], blob_length);
403 
404     return gatt_client_send(gatt_client,  5u + blob_length);
405 }
406 
407 static uint8_t att_exchange_mtu_request(gatt_client_t *gatt_client) {
408     uint16_t mtu = l2cap_max_le_mtu();
409     l2cap_reserve_packet_buffer();
410     uint8_t * request = l2cap_get_outgoing_buffer();
411     request[0] = ATT_EXCHANGE_MTU_REQUEST;
412     little_endian_store_16(request, 1, mtu);
413 
414     return gatt_client_send(gatt_client, 3);
415 }
416 
417 static uint16_t write_blob_length(gatt_client_t * gatt_client){
418     uint16_t max_blob_length = gatt_client->mtu - 5u;
419     if (gatt_client->attribute_offset >= gatt_client->attribute_length) {
420         return 0;
421     }
422     uint16_t rest_length = gatt_client->attribute_length - gatt_client->attribute_offset;
423     if (max_blob_length > rest_length){
424         return rest_length;
425     }
426     return max_blob_length;
427 }
428 
429 static void send_gatt_services_request(gatt_client_t *gatt_client){
430     att_read_by_type_or_group_request_for_uuid16(gatt_client, ATT_READ_BY_GROUP_TYPE_REQUEST,
431                                                  gatt_client->uuid16, gatt_client->start_group_handle,
432                                                  gatt_client->end_group_handle);
433 }
434 
435 static void send_gatt_by_uuid_request(gatt_client_t *gatt_client, uint16_t attribute_group_type){
436     if (gatt_client->uuid16){
437         uint8_t uuid16[2];
438         little_endian_store_16(uuid16, 0, gatt_client->uuid16);
439         att_find_by_type_value_request(gatt_client, ATT_FIND_BY_TYPE_VALUE_REQUEST, attribute_group_type,
440                                        gatt_client->start_group_handle, gatt_client->end_group_handle, uuid16, 2);
441         return;
442     }
443     uint8_t uuid128[16];
444     reverse_128(gatt_client->uuid128, uuid128);
445     att_find_by_type_value_request(gatt_client, ATT_FIND_BY_TYPE_VALUE_REQUEST, attribute_group_type,
446                                    gatt_client->start_group_handle, gatt_client->end_group_handle, uuid128, 16);
447 }
448 
449 static void send_gatt_services_by_uuid_request(gatt_client_t *gatt_client){
450     send_gatt_by_uuid_request(gatt_client, GATT_PRIMARY_SERVICE_UUID);
451 }
452 
453 static void send_gatt_included_service_uuid_request(gatt_client_t *gatt_client){
454     att_read_request(gatt_client, ATT_READ_REQUEST, gatt_client->query_start_handle);
455 }
456 
457 static void send_gatt_included_service_request(gatt_client_t *gatt_client){
458     att_read_by_type_or_group_request_for_uuid16(gatt_client, ATT_READ_BY_TYPE_REQUEST,
459                                                  GATT_INCLUDE_SERVICE_UUID, gatt_client->start_group_handle,
460                                                  gatt_client->end_group_handle);
461 }
462 
463 static void send_gatt_characteristic_request(gatt_client_t *gatt_client){
464     att_read_by_type_or_group_request_for_uuid16(gatt_client, ATT_READ_BY_TYPE_REQUEST,
465                                                  GATT_CHARACTERISTICS_UUID, gatt_client->start_group_handle,
466                                                  gatt_client->end_group_handle);
467 }
468 
469 static void send_gatt_characteristic_descriptor_request(gatt_client_t *gatt_client){
470     att_find_information_request(gatt_client, ATT_FIND_INFORMATION_REQUEST, gatt_client->start_group_handle,
471                                  gatt_client->end_group_handle);
472 }
473 
474 static void send_gatt_read_characteristic_value_request(gatt_client_t *gatt_client){
475     att_read_request(gatt_client, ATT_READ_REQUEST, gatt_client->attribute_handle);
476 }
477 
478 static void send_gatt_read_by_type_request(gatt_client_t * gatt_client){
479     if (gatt_client->uuid16){
480         att_read_by_type_or_group_request_for_uuid16(gatt_client, ATT_READ_BY_TYPE_REQUEST,
481                                                      gatt_client->uuid16, gatt_client->start_group_handle,
482                                                      gatt_client->end_group_handle);
483     } else {
484         att_read_by_type_or_group_request_for_uuid128(gatt_client, ATT_READ_BY_TYPE_REQUEST,
485                                                       gatt_client->uuid128, gatt_client->start_group_handle,
486                                                       gatt_client->end_group_handle);
487     }
488 }
489 
490 static void send_gatt_read_blob_request(gatt_client_t *gatt_client){
491     if (gatt_client->attribute_offset == 0){
492         att_read_request(gatt_client, ATT_READ_REQUEST, gatt_client->attribute_handle);
493     } else {
494         att_read_blob_request(gatt_client, ATT_READ_BLOB_REQUEST, gatt_client->attribute_handle,
495                               gatt_client->attribute_offset);
496     }
497 }
498 
499 static void send_gatt_read_multiple_request(gatt_client_t * gatt_client){
500     att_read_multiple_request(gatt_client, gatt_client->read_multiple_handle_count, gatt_client->read_multiple_handles);
501 }
502 
503 static void send_gatt_write_attribute_value_request(gatt_client_t * gatt_client){
504     att_write_request(gatt_client, ATT_WRITE_REQUEST, gatt_client->attribute_handle, gatt_client->attribute_length,
505                       gatt_client->attribute_value);
506 }
507 
508 static void send_gatt_write_client_characteristic_configuration_request(gatt_client_t * gatt_client){
509     att_write_request(gatt_client, ATT_WRITE_REQUEST, gatt_client->client_characteristic_configuration_handle, 2,
510                       gatt_client->client_characteristic_configuration_value);
511 }
512 
513 static void send_gatt_prepare_write_request(gatt_client_t * gatt_client){
514     att_prepare_write_request(gatt_client, ATT_PREPARE_WRITE_REQUEST, gatt_client->attribute_handle,
515                               gatt_client->attribute_offset, write_blob_length(gatt_client),
516                               gatt_client->attribute_value);
517 }
518 
519 static void send_gatt_execute_write_request(gatt_client_t * gatt_client){
520     att_execute_write_request(gatt_client, ATT_EXECUTE_WRITE_REQUEST, 1);
521 }
522 
523 static void send_gatt_cancel_prepared_write_request(gatt_client_t * gatt_client){
524     att_execute_write_request(gatt_client, ATT_EXECUTE_WRITE_REQUEST, 0);
525 }
526 
527 #ifndef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
528 static void send_gatt_read_client_characteristic_configuration_request(gatt_client_t * gatt_client){
529     att_read_by_type_or_group_request_for_uuid16(gatt_client, ATT_READ_BY_TYPE_REQUEST,
530                                                  GATT_CLIENT_CHARACTERISTICS_CONFIGURATION,
531                                                  gatt_client->start_group_handle, gatt_client->end_group_handle);
532 }
533 #endif
534 
535 static void send_gatt_read_characteristic_descriptor_request(gatt_client_t * gatt_client){
536     att_read_request(gatt_client, ATT_READ_REQUEST, gatt_client->attribute_handle);
537 }
538 
539 #ifdef ENABLE_LE_SIGNED_WRITE
540 static void send_gatt_signed_write_request(gatt_client_t * gatt_client, uint32_t sign_counter){
541     att_signed_write_request(gatt_client, ATT_SIGNED_WRITE_COMMAND, gatt_client->attribute_handle,
542                              gatt_client->attribute_length, gatt_client->attribute_value, sign_counter,
543                              gatt_client->cmac);
544 }
545 #endif
546 
547 static uint16_t get_last_result_handle_from_service_list(uint8_t * packet, uint16_t size){
548     if (size < 2) return 0xffff;
549     uint8_t attr_length = packet[1];
550     if ((2 + attr_length) > size) return 0xffff;
551     return little_endian_read_16(packet, size - attr_length + 2u);
552 }
553 
554 static uint16_t get_last_result_handle_from_characteristics_list(uint8_t * packet, uint16_t size){
555     if (size < 2) return 0xffff;
556     uint8_t attr_length = packet[1];
557     if ((2 + attr_length) > size) return 0xffff;
558     return little_endian_read_16(packet, size - attr_length + 3u);
559 }
560 
561 static uint16_t get_last_result_handle_from_included_services_list(uint8_t * packet, uint16_t size){
562     if (size < 2) return 0xffff;
563     uint8_t attr_length = packet[1];
564     if ((2 + attr_length) > size) return 0xffff;
565     return little_endian_read_16(packet, size - attr_length);
566 }
567 
568 static void gatt_client_notify_can_send_query(gatt_client_t * gatt_client){
569     while (gatt_client->gatt_client_state == P_READY){
570         btstack_context_callback_registration_t * callback = (btstack_context_callback_registration_t *) btstack_linked_list_pop(&gatt_client->query_requests);
571         if (callback == NULL) {
572             return;
573         }
574         (*callback->callback)(callback->context);
575     }
576 }
577 
578 static void gatt_client_handle_transaction_complete(gatt_client_t * gatt_client){
579     gatt_client->gatt_client_state = P_READY;
580     gatt_client_timeout_stop(gatt_client);
581     gatt_client_notify_can_send_query(gatt_client);
582 }
583 
584 static void emit_event_new(btstack_packet_handler_t callback, uint8_t * packet, uint16_t size){
585     if (!callback) return;
586     hci_dump_packet(HCI_EVENT_PACKET, 1, packet, size);
587     (*callback)(HCI_EVENT_PACKET, 0, packet, size);
588 }
589 
590 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){
591     notification->callback = callback;
592     notification->con_handle = con_handle;
593     if (characteristic == NULL){
594         notification->attribute_handle = GATT_CLIENT_ANY_VALUE_HANDLE;
595     } else {
596         notification->attribute_handle = characteristic->value_handle;
597     }
598     btstack_linked_list_add(&gatt_client_value_listeners, (btstack_linked_item_t*) notification);
599 }
600 
601 void gatt_client_stop_listening_for_characteristic_value_updates(gatt_client_notification_t * notification){
602     btstack_linked_list_remove(&gatt_client_value_listeners, (btstack_linked_item_t*) notification);
603 }
604 
605 static void emit_event_to_registered_listeners(hci_con_handle_t con_handle, uint16_t attribute_handle, uint8_t * packet, uint16_t size){
606     btstack_linked_list_iterator_t it;
607     btstack_linked_list_iterator_init(&it, &gatt_client_value_listeners);
608     while (btstack_linked_list_iterator_has_next(&it)){
609         gatt_client_notification_t * notification = (gatt_client_notification_t*) btstack_linked_list_iterator_next(&it);
610         if ((notification->con_handle       != GATT_CLIENT_ANY_CONNECTION)   && (notification->con_handle       != con_handle)) continue;
611         if ((notification->attribute_handle != GATT_CLIENT_ANY_VALUE_HANDLE) && (notification->attribute_handle != attribute_handle)) continue;
612         (*notification->callback)(HCI_EVENT_PACKET, 0, packet, size);
613     }
614 }
615 
616 static void emit_gatt_complete_event(gatt_client_t * gatt_client, uint8_t att_status){
617     // @format H1
618     uint8_t packet[5];
619     packet[0] = GATT_EVENT_QUERY_COMPLETE;
620     packet[1] = 3;
621     little_endian_store_16(packet, 2, gatt_client->con_handle);
622     packet[4] = att_status;
623     emit_event_new(gatt_client->callback, packet, sizeof(packet));
624 }
625 
626 static void emit_gatt_service_query_result_event(gatt_client_t * gatt_client, uint16_t start_group_handle, uint16_t end_group_handle, const uint8_t * uuid128){
627     // @format HX
628     uint8_t packet[24];
629     packet[0] = GATT_EVENT_SERVICE_QUERY_RESULT;
630     packet[1] = sizeof(packet) - 2u;
631     little_endian_store_16(packet, 2, gatt_client->con_handle);
632     ///
633     little_endian_store_16(packet, 4, start_group_handle);
634     little_endian_store_16(packet, 6, end_group_handle);
635     reverse_128(uuid128, &packet[8]);
636     emit_event_new(gatt_client->callback, packet, sizeof(packet));
637 }
638 
639 static void emit_gatt_included_service_query_result_event(gatt_client_t * gatt_client, uint16_t include_handle, uint16_t start_group_handle, uint16_t end_group_handle, const uint8_t * uuid128){
640     // @format HX
641     uint8_t packet[26];
642     packet[0] = GATT_EVENT_INCLUDED_SERVICE_QUERY_RESULT;
643     packet[1] = sizeof(packet) - 2u;
644     little_endian_store_16(packet, 2, gatt_client->con_handle);
645     ///
646     little_endian_store_16(packet, 4, include_handle);
647     //
648     little_endian_store_16(packet, 6, start_group_handle);
649     little_endian_store_16(packet, 8, end_group_handle);
650     reverse_128(uuid128, &packet[10]);
651     emit_event_new(gatt_client->callback, packet, sizeof(packet));
652 }
653 
654 static void emit_gatt_characteristic_query_result_event(gatt_client_t * gatt_client, uint16_t start_handle, uint16_t value_handle, uint16_t end_handle,
655                                                         uint16_t properties, const uint8_t * uuid128){
656     // @format HY
657     uint8_t packet[28];
658     packet[0] = GATT_EVENT_CHARACTERISTIC_QUERY_RESULT;
659     packet[1] = sizeof(packet) - 2u;
660     little_endian_store_16(packet, 2, gatt_client->con_handle);
661     ///
662     little_endian_store_16(packet, 4,  start_handle);
663     little_endian_store_16(packet, 6,  value_handle);
664     little_endian_store_16(packet, 8,  end_handle);
665     little_endian_store_16(packet, 10, properties);
666     reverse_128(uuid128, &packet[12]);
667     emit_event_new(gatt_client->callback, packet, sizeof(packet));
668 }
669 
670 static void emit_gatt_all_characteristic_descriptors_result_event(
671         gatt_client_t * gatt_client, uint16_t descriptor_handle, const uint8_t * uuid128){
672     // @format HZ
673     uint8_t packet[22];
674     packet[0] = GATT_EVENT_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT;
675     packet[1] = sizeof(packet) - 2u;
676     little_endian_store_16(packet, 2, gatt_client->con_handle);
677     ///
678     little_endian_store_16(packet, 4,  descriptor_handle);
679     reverse_128(uuid128, &packet[6]);
680     emit_event_new(gatt_client->callback, packet, sizeof(packet));
681 }
682 
683 static void emit_gatt_mtu_exchanged_result_event(gatt_client_t * gatt_client, uint16_t new_mtu){
684     // @format H2
685     uint8_t packet[6];
686     packet[0] = GATT_EVENT_MTU;
687     packet[1] = sizeof(packet) - 2u;
688     little_endian_store_16(packet, 2, gatt_client->con_handle);
689     little_endian_store_16(packet, 4, new_mtu);
690     att_dispatch_client_mtu_exchanged(gatt_client->con_handle, new_mtu);
691     emit_event_new(gatt_client->callback, packet, sizeof(packet));
692 }
693 ///
694 static void report_gatt_services(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size){
695     if (size < 2) return;
696     uint8_t attr_length = packet[1];
697     uint8_t uuid_length = attr_length - 4u;
698 
699     int i;
700     for (i = 2; (i+attr_length) <= size; i += attr_length){
701         uint16_t start_group_handle = little_endian_read_16(packet,i);
702         uint16_t end_group_handle   = little_endian_read_16(packet,i+2);
703         uint8_t  uuid128[16];
704         uint16_t uuid16 = 0;
705 
706         if (uuid_length == 2u){
707             uuid16 = little_endian_read_16(packet, i+4);
708             uuid_add_bluetooth_prefix((uint8_t*) &uuid128, uuid16);
709         } else if (uuid_length == 16u) {
710             reverse_128(&packet[i+4], uuid128);
711         } else {
712             return;
713         }
714         emit_gatt_service_query_result_event(gatt_client, start_group_handle, end_group_handle, uuid128);
715     }
716 }
717 
718 // helper
719 static void characteristic_start_found(gatt_client_t * gatt_client, uint16_t start_handle, uint8_t properties, uint16_t value_handle, uint8_t * uuid, uint16_t uuid_length){
720     uint8_t uuid128[16];
721     uint16_t uuid16 = 0;
722     if (uuid_length == 2u){
723         uuid16 = little_endian_read_16(uuid, 0);
724         uuid_add_bluetooth_prefix((uint8_t*) uuid128, uuid16);
725     } else if (uuid_length == 16u){
726         reverse_128(uuid, uuid128);
727     } else {
728         return;
729     }
730 
731     if (gatt_client->filter_with_uuid && (memcmp(gatt_client->uuid128, uuid128, 16) != 0)) return;
732 
733     gatt_client->characteristic_properties = properties;
734     gatt_client->characteristic_start_handle = start_handle;
735     gatt_client->attribute_handle = value_handle;
736 
737     if (gatt_client->filter_with_uuid) return;
738 
739     gatt_client->uuid16 = uuid16;
740     (void)memcpy(gatt_client->uuid128, uuid128, 16);
741 }
742 
743 static void characteristic_end_found(gatt_client_t * gatt_client, uint16_t end_handle){
744     // TODO: stop searching if filter and uuid found
745 
746     if (!gatt_client->characteristic_start_handle) return;
747 
748     emit_gatt_characteristic_query_result_event(gatt_client, gatt_client->characteristic_start_handle, gatt_client->attribute_handle,
749                                                 end_handle, gatt_client->characteristic_properties, gatt_client->uuid128);
750 
751     gatt_client->characteristic_start_handle = 0;
752 }
753 
754 static void report_gatt_characteristics(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size){
755     if (size < 2u) return;
756     uint8_t attr_length = packet[1];
757     if ((attr_length != 7u) && (attr_length != 21u)) return;
758     uint8_t uuid_length = attr_length - 5u;
759     int i;
760     for (i = 2u; (i + attr_length) <= size; i += attr_length){
761         uint16_t start_handle = little_endian_read_16(packet, i);
762         uint8_t  properties = packet[i+2];
763         uint16_t value_handle = little_endian_read_16(packet, i+3);
764         characteristic_end_found(gatt_client, start_handle - 1u);
765         characteristic_start_found(gatt_client, start_handle, properties, value_handle, &packet[i + 5], uuid_length);
766     }
767 }
768 
769 static void report_gatt_included_service_uuid16(gatt_client_t * gatt_client, uint16_t include_handle, uint16_t uuid16){
770     uint8_t normalized_uuid128[16];
771     uuid_add_bluetooth_prefix(normalized_uuid128, uuid16);
772     emit_gatt_included_service_query_result_event(gatt_client, include_handle, gatt_client->query_start_handle,
773                                                   gatt_client->query_end_handle, normalized_uuid128);
774 }
775 
776 static void report_gatt_included_service_uuid128(gatt_client_t * gatt_client, uint16_t include_handle, const uint8_t * uuid128){
777     emit_gatt_included_service_query_result_event(gatt_client, include_handle, gatt_client->query_start_handle,
778                                                   gatt_client->query_end_handle, uuid128);
779 }
780 
781 // @return packet pointer
782 // @note assume that value is part of an l2cap buffer - overwrite HCI + L2CAP packet headers
783 static const int characteristic_value_event_header_size = 8;
784 static uint8_t * setup_characteristic_value_packet(uint8_t type, hci_con_handle_t con_handle, uint16_t attribute_handle, uint8_t * value, uint16_t length){
785 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
786     // copy value into test packet for testing
787     static uint8_t packet[1000];
788     memcpy(&packet[8], value, length);
789 #else
790     // before the value inside the ATT PDU
791     uint8_t * packet = value - characteristic_value_event_header_size;
792 #endif
793     packet[0] = type;
794     packet[1] = characteristic_value_event_header_size - 2 + length;
795     little_endian_store_16(packet, 2, con_handle);
796     little_endian_store_16(packet, 4, attribute_handle);
797     little_endian_store_16(packet, 6, length);
798     return packet;
799 }
800 
801 // @return packet pointer
802 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
803 static const int long_characteristic_value_event_header_size = 10;
804 static uint8_t * setup_long_characteristic_value_packet(uint8_t type, hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t offset, uint8_t * value, uint16_t length){
805 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
806     // avoid using pre ATT headers.
807     return NULL;
808 #endif
809 #if defined(HCI_INCOMING_PRE_BUFFER_SIZE) && (HCI_INCOMING_PRE_BUFFER_SIZE >= 10 - 8) // L2CAP Header (4) - ACL Header (4)
810     // before the value inside the ATT PDU
811     uint8_t * packet = value - long_characteristic_value_event_header_size;
812     packet[0] = type;
813     packet[1] = long_characteristic_value_event_header_size - 2 + length;
814     little_endian_store_16(packet, 2, con_handle);
815     little_endian_store_16(packet, 4, attribute_handle);
816     little_endian_store_16(packet, 6, offset);
817     little_endian_store_16(packet, 8, length);
818     return packet;
819 #else
820     log_error("HCI_INCOMING_PRE_BUFFER_SIZE >= 2 required for long characteristic reads");
821     return NULL;
822 #endif
823 }
824 
825 // test if notification/indication should be delivered to application (BLESA)
826 static bool gatt_client_accept_server_message(gatt_client_t *gatt_client) {
827 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION
828 	// ignore messages until re-encryption is complete
829     if (gap_reconnect_security_setup_active(gatt_client->con_handle)) return false;
830 
831 	// after that ignore if bonded but not encrypted
832 	return !gap_bonded(gatt_client->con_handle) || (gap_encryption_key_size(gatt_client->con_handle) > 0);
833 #else
834     UNUSED(gatt_client);
835 	return true;
836 #endif
837 }
838 
839 
840 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
841 static void report_gatt_notification(gatt_client_t *gatt_client, uint16_t value_handle, uint8_t *value, int length) {
842 	if (!gatt_client_accept_server_message(gatt_client)) return;
843     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_NOTIFICATION, gatt_client->con_handle, value_handle, value, length);
844     emit_event_to_registered_listeners(gatt_client->con_handle, value_handle, packet, characteristic_value_event_header_size + length);
845 }
846 
847 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
848 static void report_gatt_indication(gatt_client_t *gatt_client, uint16_t value_handle, uint8_t *value, int length) {
849 	if (!gatt_client_accept_server_message(gatt_client)) return;
850     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_INDICATION, gatt_client->con_handle, value_handle, value, length);
851     emit_event_to_registered_listeners(gatt_client->con_handle, value_handle, packet, characteristic_value_event_header_size + length);
852 }
853 
854 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
855 static void report_gatt_characteristic_value(gatt_client_t * gatt_client, uint16_t attribute_handle, uint8_t * value, uint16_t length){
856     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT, gatt_client->con_handle, attribute_handle, value, length);
857     emit_event_new(gatt_client->callback, packet, characteristic_value_event_header_size + length);
858 }
859 
860 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
861 static void report_gatt_long_characteristic_value_blob(gatt_client_t * gatt_client, uint16_t attribute_handle, uint8_t * blob, uint16_t blob_length, int value_offset){
862     uint8_t * packet = setup_long_characteristic_value_packet(GATT_EVENT_LONG_CHARACTERISTIC_VALUE_QUERY_RESULT, gatt_client->con_handle, attribute_handle, value_offset, blob, blob_length);
863     if (!packet) return;
864     emit_event_new(gatt_client->callback, packet, blob_length + long_characteristic_value_event_header_size);
865 }
866 
867 static void report_gatt_characteristic_descriptor(gatt_client_t * gatt_client, uint16_t descriptor_handle, uint8_t *value, uint16_t value_length, uint16_t value_offset){
868     UNUSED(value_offset);
869     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT, gatt_client->con_handle, descriptor_handle, value, value_length);
870     emit_event_new(gatt_client->callback, packet, value_length + 8u);
871 }
872 
873 static void report_gatt_long_characteristic_descriptor(gatt_client_t * gatt_client, uint16_t descriptor_handle, uint8_t *blob, uint16_t blob_length, uint16_t value_offset){
874     uint8_t * packet = setup_long_characteristic_value_packet(GATT_EVENT_LONG_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT, gatt_client->con_handle, descriptor_handle, value_offset, blob, blob_length);
875     if (!packet) return;
876     emit_event_new(gatt_client->callback, packet, blob_length + long_characteristic_value_event_header_size);
877 }
878 
879 static void report_gatt_all_characteristic_descriptors(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size, uint16_t pair_size){
880     int i;
881     for (i = 0u; (i + pair_size) <= size; i += pair_size){
882         uint16_t descriptor_handle = little_endian_read_16(packet,i);
883         uint8_t uuid128[16];
884         uint16_t uuid16 = 0;
885         if (pair_size == 4u){
886             uuid16 = little_endian_read_16(packet,i+2);
887             uuid_add_bluetooth_prefix(uuid128, uuid16);
888         } else {
889             reverse_128(&packet[i+2], uuid128);
890         }
891         emit_gatt_all_characteristic_descriptors_result_event(gatt_client, descriptor_handle, uuid128);
892     }
893 
894 }
895 
896 static int is_query_done(gatt_client_t * gatt_client, uint16_t last_result_handle){
897     return last_result_handle >= gatt_client->end_group_handle;
898 }
899 
900 static void trigger_next_query(gatt_client_t * gatt_client, uint16_t last_result_handle, gatt_client_state_t next_query_state){
901     if (is_query_done(gatt_client, last_result_handle)){
902         gatt_client_handle_transaction_complete(gatt_client);
903         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
904         return;
905     }
906     // next
907     gatt_client->start_group_handle = last_result_handle + 1u;
908     gatt_client->gatt_client_state = next_query_state;
909 }
910 
911 static void trigger_next_included_service_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
912     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_INCLUDED_SERVICE_QUERY);
913 }
914 
915 static void trigger_next_service_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
916     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_SERVICE_QUERY);
917 }
918 
919 static void trigger_next_service_by_uuid_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
920     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_SERVICE_WITH_UUID_QUERY);
921 }
922 
923 static void trigger_next_characteristic_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
924     if (is_query_done(gatt_client, last_result_handle)){
925         // report last characteristic
926         characteristic_end_found(gatt_client, gatt_client->end_group_handle);
927     }
928     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY);
929 }
930 
931 static void trigger_next_characteristic_descriptor_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
932     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY);
933 }
934 
935 static void trigger_next_read_by_type_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
936     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_READ_BY_TYPE_REQUEST);
937 }
938 
939 static void trigger_next_prepare_write_query(gatt_client_t * gatt_client, gatt_client_state_t next_query_state, gatt_client_state_t done_state){
940     gatt_client->attribute_offset += write_blob_length(gatt_client);
941     uint16_t next_blob_length =  write_blob_length(gatt_client);
942 
943     if (next_blob_length == 0u){
944         gatt_client->gatt_client_state = done_state;
945         return;
946     }
947     gatt_client->gatt_client_state = next_query_state;
948 }
949 
950 static void trigger_next_blob_query(gatt_client_t * gatt_client, gatt_client_state_t next_query_state, uint16_t received_blob_length){
951 
952     uint16_t max_blob_length = gatt_client->mtu - 1u;
953     if (received_blob_length < max_blob_length){
954         gatt_client_handle_transaction_complete(gatt_client);
955         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
956         return;
957     }
958 
959     gatt_client->attribute_offset += received_blob_length;
960     gatt_client->gatt_client_state = next_query_state;
961 }
962 
963 
964 static int is_value_valid(gatt_client_t *gatt_client, uint8_t *packet, uint16_t size){
965     uint16_t attribute_handle = little_endian_read_16(packet, 1);
966     uint16_t value_offset = little_endian_read_16(packet, 3);
967 
968     if (gatt_client->attribute_handle != attribute_handle) return 0;
969     if (gatt_client->attribute_offset != value_offset) return 0;
970     return memcmp(&gatt_client->attribute_value[gatt_client->attribute_offset], &packet[5], size - 5u) == 0u;
971 }
972 
973 // returns 1 if packet was sent
974 static bool gatt_client_run_for_gatt_client(gatt_client_t * gatt_client){
975 
976     // wait until re-encryption is complete
977     if (gap_reconnect_security_setup_active(gatt_client->con_handle)) return false;
978 
979     // wait until re-encryption is complete
980     if (gatt_client->reencryption_active) return false;
981 
982     // wait until pairing complete (either reactive authentication or due to required security level)
983     if (gatt_client->wait_for_authentication_complete) return false;
984 
985     bool client_request_pending = gatt_client->gatt_client_state != P_READY;
986 
987     // verify security level for Mandatory Authentication
988     if (client_request_pending && (gatt_client_required_security_level > gatt_client->security_level)){
989         log_info("Trigger pairing, current security level %u, required %u\n", gatt_client->security_level, gatt_client_required_security_level);
990         gatt_client->wait_for_authentication_complete = 1;
991         // set att error code for pairing failure based on required level
992         switch (gatt_client_required_security_level){
993             case LEVEL_4:
994             case LEVEL_3:
995                 gatt_client->pending_error_code = ATT_ERROR_INSUFFICIENT_AUTHENTICATION;
996                 break;
997             default:
998                 gatt_client->pending_error_code = ATT_ERROR_INSUFFICIENT_ENCRYPTION;
999                 break;
1000         }
1001         sm_request_pairing(gatt_client->con_handle);
1002         // sm probably just sent a pdu
1003         return true;
1004     }
1005 
1006     switch (gatt_client->mtu_state) {
1007         case SEND_MTU_EXCHANGE:
1008             gatt_client->mtu_state = SENT_MTU_EXCHANGE;
1009             att_exchange_mtu_request(gatt_client);
1010             return true;
1011         case SENT_MTU_EXCHANGE:
1012             return false;
1013         default:
1014             break;
1015     }
1016 
1017     if (gatt_client->send_confirmation){
1018         gatt_client->send_confirmation = 0;
1019         att_confirmation(gatt_client);
1020         return true;
1021     }
1022 
1023     // check MTU for writes
1024     switch (gatt_client->gatt_client_state){
1025         case P_W2_SEND_WRITE_CHARACTERISTIC_VALUE:
1026         case P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR:
1027             if (gatt_client->attribute_length <= (gatt_client->mtu - 3u)) break;
1028             log_error("gatt_client_run: value len %u > MTU %u - 3\n", gatt_client->attribute_length,gatt_client->mtu);
1029             gatt_client_handle_transaction_complete(gatt_client);
1030             emit_gatt_complete_event(gatt_client, ATT_ERROR_INVALID_ATTRIBUTE_VALUE_LENGTH);
1031             return false;
1032         default:
1033             break;
1034     }
1035 
1036     switch (gatt_client->gatt_client_state){
1037         case P_W2_SEND_SERVICE_QUERY:
1038             gatt_client->gatt_client_state = P_W4_SERVICE_QUERY_RESULT;
1039             send_gatt_services_request(gatt_client);
1040             return true;
1041 
1042         case P_W2_SEND_SERVICE_WITH_UUID_QUERY:
1043             gatt_client->gatt_client_state = P_W4_SERVICE_WITH_UUID_RESULT;
1044             send_gatt_services_by_uuid_request(gatt_client);
1045             return true;
1046 
1047         case P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY:
1048             gatt_client->gatt_client_state = P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT;
1049             send_gatt_characteristic_request(gatt_client);
1050             return true;
1051 
1052         case P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY:
1053             gatt_client->gatt_client_state = P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT;
1054             send_gatt_characteristic_request(gatt_client);
1055             return true;
1056 
1057         case P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY:
1058             gatt_client->gatt_client_state = P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT;
1059             send_gatt_characteristic_descriptor_request(gatt_client);
1060             return true;
1061 
1062         case P_W2_SEND_INCLUDED_SERVICE_QUERY:
1063             gatt_client->gatt_client_state = P_W4_INCLUDED_SERVICE_QUERY_RESULT;
1064             send_gatt_included_service_request(gatt_client);
1065             return true;
1066 
1067         case P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY:
1068             gatt_client->gatt_client_state = P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT;
1069             send_gatt_included_service_uuid_request(gatt_client);
1070             return true;
1071 
1072         case P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY:
1073             gatt_client->gatt_client_state = P_W4_READ_CHARACTERISTIC_VALUE_RESULT;
1074             send_gatt_read_characteristic_value_request(gatt_client);
1075             return true;
1076 
1077         case P_W2_SEND_READ_BLOB_QUERY:
1078             gatt_client->gatt_client_state = P_W4_READ_BLOB_RESULT;
1079             send_gatt_read_blob_request(gatt_client);
1080             return true;
1081 
1082         case P_W2_SEND_READ_BY_TYPE_REQUEST:
1083             gatt_client->gatt_client_state = P_W4_READ_BY_TYPE_RESPONSE;
1084             send_gatt_read_by_type_request(gatt_client);
1085             return true;
1086 
1087         case P_W2_SEND_READ_MULTIPLE_REQUEST:
1088             gatt_client->gatt_client_state = P_W4_READ_MULTIPLE_RESPONSE;
1089             send_gatt_read_multiple_request(gatt_client);
1090             return true;
1091 
1092         case P_W2_SEND_WRITE_CHARACTERISTIC_VALUE:
1093             gatt_client->gatt_client_state = P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT;
1094             send_gatt_write_attribute_value_request(gatt_client);
1095             return true;
1096 
1097         case P_W2_PREPARE_WRITE:
1098             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_RESULT;
1099             send_gatt_prepare_write_request(gatt_client);
1100             return true;
1101 
1102         case P_W2_PREPARE_WRITE_SINGLE:
1103             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_SINGLE_RESULT;
1104             send_gatt_prepare_write_request(gatt_client);
1105             return true;
1106 
1107         case P_W2_PREPARE_RELIABLE_WRITE:
1108             gatt_client->gatt_client_state = P_W4_PREPARE_RELIABLE_WRITE_RESULT;
1109             send_gatt_prepare_write_request(gatt_client);
1110             return true;
1111 
1112         case P_W2_EXECUTE_PREPARED_WRITE:
1113             gatt_client->gatt_client_state = P_W4_EXECUTE_PREPARED_WRITE_RESULT;
1114             send_gatt_execute_write_request(gatt_client);
1115             return true;
1116 
1117         case P_W2_CANCEL_PREPARED_WRITE:
1118             gatt_client->gatt_client_state = P_W4_CANCEL_PREPARED_WRITE_RESULT;
1119             send_gatt_cancel_prepared_write_request(gatt_client);
1120             return true;
1121 
1122         case P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH:
1123             gatt_client->gatt_client_state = P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT;
1124             send_gatt_cancel_prepared_write_request(gatt_client);
1125             return true;
1126 
1127 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1128         case P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY:
1129             // use Find Information
1130             gatt_client->gatt_client_state = P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT;
1131             send_gatt_characteristic_descriptor_request(gatt_client);
1132 #else
1133         case P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY:
1134             // Use Read By Type
1135             gatt_client->gatt_client_state = P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT;
1136             send_gatt_read_client_characteristic_configuration_request(gatt_client);
1137 #endif
1138             return true;
1139 
1140         case P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY:
1141             gatt_client->gatt_client_state = P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT;
1142             send_gatt_read_characteristic_descriptor_request(gatt_client);
1143             return true;
1144 
1145         case P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY:
1146             gatt_client->gatt_client_state = P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT;
1147             send_gatt_read_blob_request(gatt_client);
1148             return true;
1149 
1150         case P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR:
1151             gatt_client->gatt_client_state = P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1152             send_gatt_write_attribute_value_request(gatt_client);
1153             return true;
1154 
1155         case P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION:
1156             gatt_client->gatt_client_state = P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT;
1157             send_gatt_write_client_characteristic_configuration_request(gatt_client);
1158             return true;
1159 
1160         case P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR:
1161             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1162             send_gatt_prepare_write_request(gatt_client);
1163             return true;
1164 
1165         case P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR:
1166             gatt_client->gatt_client_state = P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1167             send_gatt_execute_write_request(gatt_client);
1168             return true;
1169 
1170 #ifdef ENABLE_LE_SIGNED_WRITE
1171         case P_W4_IDENTITY_RESOLVING:
1172             log_info("P_W4_IDENTITY_RESOLVING - state %x", sm_identity_resolving_state(gatt_client->con_handle));
1173             switch (sm_identity_resolving_state(gatt_client->con_handle)){
1174                 case IRK_LOOKUP_SUCCEEDED:
1175                     gatt_client->le_device_index = sm_le_device_index(gatt_client->con_handle);
1176                     gatt_client->gatt_client_state = P_W4_CMAC_READY;
1177                     break;
1178                 case IRK_LOOKUP_FAILED:
1179                     gatt_client_handle_transaction_complete(gatt_client);
1180                     emit_gatt_complete_event(gatt_client, ATT_ERROR_BONDING_INFORMATION_MISSING);
1181                     return false;
1182                 default:
1183                     return false;
1184             }
1185 
1186             /* Fall through */
1187 
1188         case P_W4_CMAC_READY:
1189             if (sm_cmac_ready()){
1190                 sm_key_t csrk;
1191                 le_device_db_local_csrk_get(gatt_client->le_device_index, csrk);
1192                 uint32_t sign_counter = le_device_db_local_counter_get(gatt_client->le_device_index);
1193                 gatt_client->gatt_client_state = P_W4_CMAC_RESULT;
1194                 sm_cmac_signed_write_start(csrk, ATT_SIGNED_WRITE_COMMAND, gatt_client->attribute_handle, gatt_client->attribute_length, gatt_client->attribute_value, sign_counter, att_signed_write_handle_cmac_result);
1195             }
1196             return false;
1197 
1198         case P_W2_SEND_SIGNED_WRITE: {
1199             gatt_client->gatt_client_state = P_W4_SEND_SINGED_WRITE_DONE;
1200             // bump local signing counter
1201             uint32_t sign_counter = le_device_db_local_counter_get(gatt_client->le_device_index);
1202             le_device_db_local_counter_set(gatt_client->le_device_index, sign_counter + 1);
1203             // send signed write command
1204             send_gatt_signed_write_request(gatt_client, sign_counter);
1205             // finally, notifiy client that write is complete
1206             gatt_client_handle_transaction_complete(gatt_client);
1207             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1208             return true;
1209         }
1210 #endif
1211         default:
1212             break;
1213     }
1214 
1215     // write without response callback
1216     btstack_context_callback_registration_t * callback =
1217             (btstack_context_callback_registration_t *) btstack_linked_list_pop(&gatt_client->write_without_response_requests);
1218     if (callback != NULL){
1219         (*callback->callback)(callback->context);
1220         return true;
1221     }
1222 
1223     // requested can send now old
1224     if (gatt_client->write_without_response_callback){
1225         btstack_packet_handler_t packet_handler = gatt_client->write_without_response_callback;
1226         gatt_client->write_without_response_callback = NULL;
1227         uint8_t event[4];
1228         event[0] = GATT_EVENT_CAN_WRITE_WITHOUT_RESPONSE;
1229         event[1] = sizeof(event) - 2u;
1230         little_endian_store_16(event, 2, gatt_client->con_handle);
1231         packet_handler(HCI_EVENT_PACKET, gatt_client->con_handle, event, sizeof(event));
1232         return true; // to trigger requeueing (even if higher layer didn't sent)
1233     }
1234 
1235     return false;
1236 }
1237 
1238 static void gatt_client_run(void){
1239     btstack_linked_item_t *it;
1240     for (it = (btstack_linked_item_t *) gatt_client_connections; it != NULL; it = it->next){
1241         gatt_client_t * gatt_client = (gatt_client_t *) it;
1242 #ifdef ENABLE_GATT_OVER_CLASSIC
1243         if (gatt_client->con_handle == HCI_CON_HANDLE_INVALID) {
1244             continue;
1245         }
1246 #endif
1247         if (!att_dispatch_client_can_send_now(gatt_client->con_handle)) {
1248             att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
1249             return;
1250         }
1251         bool packet_sent = gatt_client_run_for_gatt_client(gatt_client);
1252         if (packet_sent){
1253             // request new permission
1254             att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
1255             // requeue client for fairness and exit
1256             // note: iterator has become invalid
1257             btstack_linked_list_remove(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1258             btstack_linked_list_add_tail(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1259             return;
1260         }
1261     }
1262 }
1263 
1264 static void gatt_client_report_error_if_pending(gatt_client_t *gatt_client, uint8_t att_error_code) {
1265     if (is_ready(gatt_client) == 1) return;
1266     gatt_client_handle_transaction_complete(gatt_client);
1267     emit_gatt_complete_event(gatt_client, att_error_code);
1268 }
1269 
1270 static void gatt_client_handle_reencryption_complete(const uint8_t * packet){
1271     hci_con_handle_t con_handle = sm_event_reencryption_complete_get_handle(packet);
1272     gatt_client_t * gatt_client = gatt_client_get_context_for_handle(con_handle);
1273     if (gatt_client == NULL) return;
1274 
1275     // update security level
1276     gatt_client->security_level = gatt_client_le_security_level_for_connection(con_handle);
1277 
1278     gatt_client->reencryption_result = sm_event_reencryption_complete_get_status(packet);
1279     gatt_client->reencryption_active = false;
1280     gatt_client->wait_for_authentication_complete = 0;
1281 
1282     if (gatt_client->gatt_client_state == P_READY) return;
1283 
1284     switch (sm_event_reencryption_complete_get_status(packet)){
1285         case ERROR_CODE_SUCCESS:
1286             log_info("re-encryption success, retry operation");
1287             break;
1288         case ERROR_CODE_AUTHENTICATION_FAILURE:
1289         case ERROR_CODE_PIN_OR_KEY_MISSING:
1290 #if defined(ENABLE_GATT_CLIENT_PAIRING) && !defined(ENABLE_LE_PROACTIVE_AUTHENTICATION)
1291             if (gatt_client_required_security_level == LEVEL_0) {
1292                 // re-encryption failed for reactive authentication with pairing and we have a pending client request
1293                 // => try to resolve it by deleting bonding information if we started pairing before
1294                 // delete bonding information
1295                 int le_device_db_index = sm_le_device_index(gatt_client->con_handle);
1296                 btstack_assert(le_device_db_index >= 0);
1297                 log_info("reactive auth with pairing: delete bonding and start pairing");
1298 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION
1299                 hci_remove_le_device_db_entry_from_resolving_list((uint16_t) le_device_db_index);
1300 #endif
1301                 le_device_db_remove(le_device_db_index);
1302                 // trigger pairing again
1303                 sm_request_pairing(gatt_client->con_handle);
1304                 break;
1305             }
1306 #endif
1307             // report bonding information missing
1308             gatt_client_handle_transaction_complete(gatt_client);
1309             emit_gatt_complete_event(gatt_client, ATT_ERROR_BONDING_INFORMATION_MISSING);
1310             break;
1311         default:
1312             // report bonding information missing
1313             gatt_client_handle_transaction_complete(gatt_client);
1314             emit_gatt_complete_event(gatt_client, gatt_client->pending_error_code);
1315             break;
1316     }
1317 }
1318 
1319 static void gatt_client_handle_disconnection_complete(const uint8_t * packet){
1320     log_info("GATT Client: HCI_EVENT_DISCONNECTION_COMPLETE");
1321     hci_con_handle_t con_handle = little_endian_read_16(packet,3);
1322     gatt_client_t * gatt_client = gatt_client_get_context_for_handle(con_handle);
1323     if (gatt_client == NULL) return;
1324 
1325     gatt_client_report_error_if_pending(gatt_client, ATT_ERROR_HCI_DISCONNECT_RECEIVED);
1326     gatt_client_timeout_stop(gatt_client);
1327     btstack_linked_list_remove(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1328     btstack_memory_gatt_client_free(gatt_client);
1329 }
1330 
1331 static void gatt_client_event_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1332     UNUSED(channel);    // ok: handling own l2cap events
1333     UNUSED(size);       // ok: there is no channel
1334 
1335     if (packet_type != HCI_EVENT_PACKET) return;
1336 
1337     hci_con_handle_t con_handle;
1338     gatt_client_t * gatt_client;
1339     switch (hci_event_packet_get_type(packet)) {
1340         case HCI_EVENT_DISCONNECTION_COMPLETE:
1341             gatt_client_handle_disconnection_complete(packet);
1342             break;
1343 
1344         // Pairing complete (with/without bonding=storing of pairing information)
1345         case SM_EVENT_PAIRING_COMPLETE:
1346             con_handle = sm_event_pairing_complete_get_handle(packet);
1347             gatt_client = gatt_client_get_context_for_handle(con_handle);
1348             if (gatt_client == NULL) break;
1349 
1350             // update security level
1351             gatt_client->security_level = gatt_client_le_security_level_for_connection(con_handle);
1352 
1353             if (gatt_client->wait_for_authentication_complete){
1354                 gatt_client->wait_for_authentication_complete = 0;
1355                 if (sm_event_pairing_complete_get_status(packet)){
1356                     log_info("pairing failed, report previous error 0x%x", gatt_client->pending_error_code);
1357                     gatt_client_report_error_if_pending(gatt_client, gatt_client->pending_error_code);
1358                 } else {
1359                     log_info("pairing success, retry operation");
1360                 }
1361             }
1362             break;
1363 
1364 #ifdef ENABLE_LE_SIGNED_WRITE
1365         // Identity Resolving completed (no code, gatt_client_run will continue)
1366         case SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED:
1367         case SM_EVENT_IDENTITY_RESOLVING_FAILED:
1368             break;
1369 #endif
1370 
1371         // re-encryption started
1372         case SM_EVENT_REENCRYPTION_STARTED:
1373             con_handle = sm_event_reencryption_complete_get_handle(packet);
1374             gatt_client = gatt_client_get_context_for_handle(con_handle);
1375             if (gatt_client == NULL) break;
1376 
1377             gatt_client->reencryption_active = true;
1378             gatt_client->reencryption_result = ERROR_CODE_SUCCESS;
1379             break;
1380 
1381         // re-encryption complete
1382         case SM_EVENT_REENCRYPTION_COMPLETE:
1383             gatt_client_handle_reencryption_complete(packet);
1384             break;
1385         default:
1386             break;
1387     }
1388 
1389     gatt_client_run();
1390 }
1391 
1392 static void gatt_client_handle_att_response(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size) {
1393     uint8_t error_code;
1394     switch (packet[0]) {
1395         case ATT_EXCHANGE_MTU_RESPONSE: {
1396             if (size < 3u) break;
1397             uint16_t remote_rx_mtu = little_endian_read_16(packet, 1);
1398             uint16_t local_rx_mtu = l2cap_max_le_mtu();
1399             uint16_t mtu = (remote_rx_mtu < local_rx_mtu) ? remote_rx_mtu : local_rx_mtu;
1400 
1401             // set gatt client mtu
1402             gatt_client->mtu = mtu;
1403             gatt_client->mtu_state = MTU_EXCHANGED;
1404 
1405             // set per connection mtu state - for fixed channel
1406             hci_connection_t *hci_connection = hci_connection_for_handle(gatt_client->con_handle);
1407             hci_connection->att_connection.mtu = gatt_client->mtu;
1408             hci_connection->att_connection.mtu_exchanged = true;
1409 
1410             emit_gatt_mtu_exchanged_result_event(gatt_client, gatt_client->mtu);
1411             break;
1412         }
1413         case ATT_READ_BY_GROUP_TYPE_RESPONSE:
1414             switch (gatt_client->gatt_client_state) {
1415                 case P_W4_SERVICE_QUERY_RESULT:
1416                     report_gatt_services(gatt_client, packet, size);
1417                     trigger_next_service_query(gatt_client, get_last_result_handle_from_service_list(packet, size));
1418                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1419                     break;
1420                 default:
1421                     break;
1422             }
1423             break;
1424         case ATT_HANDLE_VALUE_NOTIFICATION:
1425             if (size < 3u) return;
1426             report_gatt_notification(gatt_client, little_endian_read_16(packet, 1u), &packet[3], size - 3u);
1427             return;
1428         case ATT_HANDLE_VALUE_INDICATION:
1429             if (size < 3u) break;
1430             report_gatt_indication(gatt_client, little_endian_read_16(packet, 1u), &packet[3], size - 3u);
1431             gatt_client->send_confirmation = 1;
1432             break;
1433 
1434         case ATT_READ_BY_TYPE_RESPONSE:
1435             switch (gatt_client->gatt_client_state) {
1436                 case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1437                     report_gatt_characteristics(gatt_client, packet, size);
1438                     trigger_next_characteristic_query(gatt_client,
1439                                                       get_last_result_handle_from_characteristics_list(packet, size));
1440                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1441                     break;
1442                 case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1443                     report_gatt_characteristics(gatt_client, packet, size);
1444                     trigger_next_characteristic_query(gatt_client,
1445                                                       get_last_result_handle_from_characteristics_list(packet, size));
1446                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1447                     break;
1448                 case P_W4_INCLUDED_SERVICE_QUERY_RESULT: {
1449                     if (size < 2u) break;
1450                     uint16_t uuid16 = 0;
1451                     uint16_t pair_size = packet[1];
1452 
1453                     if (pair_size == 6u) {
1454                         if (size < 8u) break;
1455                         // UUIDs not available, query first included service
1456                         gatt_client->start_group_handle = little_endian_read_16(packet, 2); // ready for next query
1457                         gatt_client->query_start_handle = little_endian_read_16(packet, 4);
1458                         gatt_client->query_end_handle = little_endian_read_16(packet, 6);
1459                         gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY;
1460                         break;
1461                     }
1462 
1463                     if (pair_size != 8u) break;
1464 
1465                     // UUIDs included, report all of them
1466                     uint16_t offset;
1467                     for (offset = 2u; (offset + 8u) <= size; offset += pair_size) {
1468                         uint16_t include_handle = little_endian_read_16(packet, offset);
1469                         gatt_client->query_start_handle = little_endian_read_16(packet, offset + 2u);
1470                         gatt_client->query_end_handle = little_endian_read_16(packet, offset + 4u);
1471                         uuid16 = little_endian_read_16(packet, offset + 6u);
1472                         report_gatt_included_service_uuid16(gatt_client, include_handle, uuid16);
1473                     }
1474 
1475                     trigger_next_included_service_query(gatt_client,
1476                                                         get_last_result_handle_from_included_services_list(packet,
1477                                                                                                            size));
1478                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1479                     break;
1480                 }
1481 #ifndef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1482                 case P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT:
1483                     gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, 2);
1484                     gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1485                     break;
1486 #endif
1487                 case P_W4_READ_BY_TYPE_RESPONSE: {
1488                     uint16_t pair_size = packet[1];
1489                     // set last result handle to last valid handle, only used if pair_size invalid
1490                     uint16_t last_result_handle = 0xffff;
1491                     if (pair_size > 2) {
1492                         uint16_t offset;
1493                         for (offset = 2; offset < size; offset += pair_size) {
1494                             uint16_t value_handle = little_endian_read_16(packet, offset);
1495                             report_gatt_characteristic_value(gatt_client, value_handle, &packet[offset + 2u],
1496                                                              pair_size - 2u);
1497                             last_result_handle = value_handle;
1498                         }
1499                     }
1500                     trigger_next_read_by_type_query(gatt_client, last_result_handle);
1501                     break;
1502                 }
1503                 default:
1504                     break;
1505             }
1506             break;
1507         case ATT_READ_RESPONSE:
1508             switch (gatt_client->gatt_client_state) {
1509                 case P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT:
1510                     if (size >= 17) {
1511                         uint8_t uuid128[16];
1512                         reverse_128(&packet[1], uuid128);
1513                         report_gatt_included_service_uuid128(gatt_client, gatt_client->start_group_handle, uuid128);
1514                     }
1515                     trigger_next_included_service_query(gatt_client, gatt_client->start_group_handle);
1516                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1517                     break;
1518 
1519                 case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1520                     gatt_client_handle_transaction_complete(gatt_client);
1521                     report_gatt_characteristic_value(gatt_client, gatt_client->attribute_handle, &packet[1], size - 1u);
1522                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1523                     break;
1524 
1525                 case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:
1526                     gatt_client_handle_transaction_complete(gatt_client);
1527                     report_gatt_characteristic_descriptor(gatt_client, gatt_client->attribute_handle, &packet[1],
1528                                                           size - 1u, 0u);
1529                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1530                     break;
1531 
1532                     // Use ATT_READ_REQUEST for first blob of Read Long Characteristic
1533                 case P_W4_READ_BLOB_RESULT:
1534                     report_gatt_long_characteristic_value_blob(gatt_client, gatt_client->attribute_handle, &packet[1],
1535                                                                size - 1u, gatt_client->attribute_offset);
1536                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_QUERY, size - 1u);
1537                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1538                     break;
1539 
1540                     // Use ATT_READ_REQUEST for first blob of Read Long Characteristic Descriptor
1541                 case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1542                     report_gatt_long_characteristic_descriptor(gatt_client, gatt_client->attribute_handle, &packet[1],
1543                                                                size - 1u, gatt_client->attribute_offset);
1544                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY,
1545                                             size - 1u);
1546                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1547                     break;
1548 
1549                 default:
1550                     break;
1551             }
1552             break;
1553 
1554         case ATT_FIND_BY_TYPE_VALUE_RESPONSE: {
1555             uint8_t pair_size = 4;
1556             int i;
1557             uint16_t start_group_handle;
1558             uint16_t end_group_handle = 0xffff; // asserts GATT_EVENT_QUERY_COMPLETE is emitted if no results
1559             for (i = 1u; (i + pair_size) <= size; i += pair_size) {
1560                 start_group_handle = little_endian_read_16(packet, i);
1561                 end_group_handle = little_endian_read_16(packet, i + 2);
1562                 emit_gatt_service_query_result_event(gatt_client, start_group_handle, end_group_handle,
1563                                                      gatt_client->uuid128);
1564             }
1565             trigger_next_service_by_uuid_query(gatt_client, end_group_handle);
1566             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1567             break;
1568         }
1569         case ATT_FIND_INFORMATION_REPLY: {
1570             if (size < 2u) break;
1571 
1572             uint8_t pair_size = 4;
1573             if (packet[1u] == 2u) {
1574                 pair_size = 18;
1575             }
1576             uint16_t offset = 2;
1577 
1578             if (size < (pair_size + offset)) break;
1579             uint16_t last_descriptor_handle = little_endian_read_16(packet, size - pair_size);
1580 
1581 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1582             log_info("ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY, state %x", gatt_client->gatt_client_state);
1583             if (gatt_client->gatt_client_state == P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT){
1584                 // iterate over descriptors looking for CCC
1585                 if (pair_size == 4){
1586                     while ((offset + 4) <= size){
1587                         uint16_t uuid16 = little_endian_read_16(packet, offset + 2);
1588                         if (uuid16 == GATT_CLIENT_CHARACTERISTICS_CONFIGURATION){
1589                             gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, offset);
1590                             gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1591                             log_info("CCC found %x", gatt_client->client_characteristic_configuration_handle);
1592                             break;
1593                         }
1594                         offset += pair_size;
1595                     }
1596                 }
1597                 if (is_query_done(gatt_client, last_descriptor_handle)){
1598 
1599                 } else {
1600                     // next
1601                     gatt_client->start_group_handle = last_descriptor_handle + 1;
1602                     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
1603                 }
1604                 break;
1605             }
1606 #endif
1607             report_gatt_all_characteristic_descriptors(gatt_client, &packet[2], size - 2u, pair_size);
1608             trigger_next_characteristic_descriptor_query(gatt_client, last_descriptor_handle);
1609             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1610             break;
1611         }
1612 
1613         case ATT_WRITE_RESPONSE:
1614             switch (gatt_client->gatt_client_state) {
1615                 case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1616                     gatt_client_handle_transaction_complete(gatt_client);
1617                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1618                     break;
1619                 case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1620                     gatt_client_handle_transaction_complete(gatt_client);
1621                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1622                     break;
1623                 case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1624                     gatt_client_handle_transaction_complete(gatt_client);
1625                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1626                     break;
1627                 default:
1628                     break;
1629             }
1630             break;
1631 
1632         case ATT_READ_BLOB_RESPONSE: {
1633             uint16_t received_blob_length = size - 1u;
1634             switch (gatt_client->gatt_client_state) {
1635                 case P_W4_READ_BLOB_RESULT:
1636                     report_gatt_long_characteristic_value_blob(gatt_client, gatt_client->attribute_handle, &packet[1],
1637                                                                received_blob_length, gatt_client->attribute_offset);
1638                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_QUERY, received_blob_length);
1639                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1640                     break;
1641                 case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1642                     report_gatt_long_characteristic_descriptor(gatt_client, gatt_client->attribute_handle,
1643                                                                &packet[1], received_blob_length,
1644                                                                gatt_client->attribute_offset);
1645                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY,
1646                                             received_blob_length);
1647                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1648                     break;
1649                 default:
1650                     break;
1651             }
1652             break;
1653         }
1654         case ATT_PREPARE_WRITE_RESPONSE:
1655             switch (gatt_client->gatt_client_state) {
1656                 case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1657                     gatt_client_handle_transaction_complete(gatt_client);
1658                     if (is_value_valid(gatt_client, packet, size)) {
1659                         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1660                     } else {
1661                         emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1662                     }
1663                     break;
1664 
1665                 case P_W4_PREPARE_WRITE_RESULT: {
1666                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1667                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE, P_W2_EXECUTE_PREPARED_WRITE);
1668                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1669                     break;
1670                 }
1671                 case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT: {
1672                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1673                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR,
1674                                                      P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR);
1675                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1676                     break;
1677                 }
1678                 case P_W4_PREPARE_RELIABLE_WRITE_RESULT: {
1679                     if (is_value_valid(gatt_client, packet, size)) {
1680                         gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1681                         trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_RELIABLE_WRITE,
1682                                                          P_W2_EXECUTE_PREPARED_WRITE);
1683                         // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1684                         break;
1685                     }
1686                     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1687                     break;
1688                 }
1689                 default:
1690                     break;
1691             }
1692             break;
1693 
1694         case ATT_EXECUTE_WRITE_RESPONSE:
1695             switch (gatt_client->gatt_client_state) {
1696                 case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1697                     gatt_client_handle_transaction_complete(gatt_client);
1698                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1699                     break;
1700                 case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1701                     gatt_client_handle_transaction_complete(gatt_client);
1702                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1703                     break;
1704                 case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1705                     gatt_client_handle_transaction_complete(gatt_client);
1706                     emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1707                     break;
1708                 case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1709                     gatt_client_handle_transaction_complete(gatt_client);
1710                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1711                     break;
1712                 default:
1713                     break;
1714 
1715             }
1716             break;
1717 
1718         case ATT_READ_MULTIPLE_RESPONSE:
1719             switch (gatt_client->gatt_client_state) {
1720                 case P_W4_READ_MULTIPLE_RESPONSE:
1721                     report_gatt_characteristic_value(gatt_client, 0u, &packet[1], size - 1u);
1722                     gatt_client_handle_transaction_complete(gatt_client);
1723                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1724                     break;
1725                 default:
1726                     break;
1727             }
1728             break;
1729 
1730         case ATT_ERROR_RESPONSE:
1731             if (size < 5u) return;
1732             error_code = packet[4];
1733             switch (error_code) {
1734                 case ATT_ERROR_ATTRIBUTE_NOT_FOUND: {
1735                     switch (gatt_client->gatt_client_state) {
1736                         case P_W4_SERVICE_QUERY_RESULT:
1737                         case P_W4_SERVICE_WITH_UUID_RESULT:
1738                         case P_W4_INCLUDED_SERVICE_QUERY_RESULT:
1739                         case P_W4_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT:
1740                             gatt_client_handle_transaction_complete(gatt_client);
1741                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1742                             break;
1743                         case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1744                         case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1745                             characteristic_end_found(gatt_client, gatt_client->end_group_handle);
1746                             gatt_client_handle_transaction_complete(gatt_client);
1747                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1748                             break;
1749                         case P_W4_READ_BY_TYPE_RESPONSE:
1750                             gatt_client_handle_transaction_complete(gatt_client);
1751                             if (gatt_client->start_group_handle == gatt_client->query_start_handle) {
1752                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_ATTRIBUTE_NOT_FOUND);
1753                             } else {
1754                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1755                             }
1756                             break;
1757                         default:
1758                             gatt_client_report_error_if_pending(gatt_client, error_code);
1759                             break;
1760                     }
1761                     break;
1762                 }
1763 
1764 #ifdef ENABLE_GATT_CLIENT_PAIRING
1765 
1766                     case ATT_ERROR_INSUFFICIENT_AUTHENTICATION:
1767                     case ATT_ERROR_INSUFFICIENT_ENCRYPTION_KEY_SIZE:
1768                     case ATT_ERROR_INSUFFICIENT_ENCRYPTION: {
1769 
1770                         // security too low
1771                         if (gatt_client->security_counter > 0) {
1772                             gatt_client_report_error_if_pending(gatt_client, error_code);
1773                             break;
1774                         }
1775                         // start security
1776                         gatt_client->security_counter++;
1777 
1778                         // setup action
1779                         int retry = 1;
1780                         switch (gatt_client->gatt_client_state){
1781                             case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1782                                 gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY ;
1783                                 break;
1784                             case P_W4_READ_BLOB_RESULT:
1785                                 gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
1786                                 break;
1787                             case P_W4_READ_BY_TYPE_RESPONSE:
1788                                 gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1789                                 break;
1790                             case P_W4_READ_MULTIPLE_RESPONSE:
1791                                 gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
1792                                 break;
1793                             case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1794                                 gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
1795                                 break;
1796                             case P_W4_PREPARE_WRITE_RESULT:
1797                                 gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
1798                                 break;
1799                             case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1800                                 gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
1801                                 break;
1802                             case P_W4_PREPARE_RELIABLE_WRITE_RESULT:
1803                                 gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
1804                                 break;
1805                             case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1806                                 gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
1807                                 break;
1808                             case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1809                                 gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
1810                                 break;
1811                             case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1812                                 gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1813                                 break;
1814                             case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:
1815                                 gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
1816                                 break;
1817                             case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1818                                 gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
1819                                 break;
1820                             case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1821                                 gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
1822                                 break;
1823                             case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1824                                 gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1825                                 break;
1826                             case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1827                                 gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
1828                                 break;
1829                             case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1830                                 gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR;
1831                                 break;
1832 #ifdef ENABLE_LE_SIGNED_WRITE
1833                             case P_W4_SEND_SINGED_WRITE_DONE:
1834                                 gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1835                                 break;
1836 #endif
1837                             default:
1838                                 log_info("retry not supported for state %x", gatt_client->gatt_client_state);
1839                                 retry = 0;
1840                                 break;
1841                         }
1842 
1843                         if (!retry) {
1844                             gatt_client_report_error_if_pending(gatt_client, error_code);
1845                             break;
1846                         }
1847 
1848                         log_info("security error, start pairing");
1849 
1850                         // start pairing for higher security level
1851                         gatt_client->wait_for_authentication_complete = 1;
1852                         gatt_client->pending_error_code = error_code;
1853                         sm_request_pairing(gatt_client->con_handle);
1854                         break;
1855                     }
1856 #endif
1857 
1858                     // nothing we can do about that
1859                 case ATT_ERROR_INSUFFICIENT_AUTHORIZATION:
1860                 default:
1861                     gatt_client_report_error_if_pending(gatt_client, error_code);
1862                     break;
1863             }
1864             break;
1865 
1866         default:
1867             log_info("ATT Handler, unhandled response type 0x%02x", packet[0]);
1868             break;
1869     }
1870 }
1871 
1872 static void gatt_client_att_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size) {
1873     gatt_client_t *gatt_client;
1874     if (size < 1u) return;
1875 
1876     if (packet_type == HCI_EVENT_PACKET) {
1877         switch (packet[0]) {
1878             case L2CAP_EVENT_CAN_SEND_NOW:
1879                 gatt_client_run();
1880                 break;
1881                 // att_server has negotiated the mtu for this connection, cache if context exists
1882             case ATT_EVENT_MTU_EXCHANGE_COMPLETE:
1883                 if (size < 6u) break;
1884                 gatt_client = gatt_client_get_context_for_handle(handle);
1885                 if (gatt_client == NULL) break;
1886                 gatt_client->mtu = little_endian_read_16(packet, 4);
1887                 break;
1888             default:
1889                 break;
1890         }
1891         return;
1892     }
1893 
1894     if (packet_type != ATT_DATA_PACKET) return;
1895 
1896     // special cases: notifications & indications motivate creating context
1897     switch (packet[0]) {
1898         case ATT_HANDLE_VALUE_NOTIFICATION:
1899         case ATT_HANDLE_VALUE_INDICATION:
1900             gatt_client_provide_context_for_handle(handle, &gatt_client);
1901             break;
1902         default:
1903             gatt_client = gatt_client_get_context_for_handle(handle);
1904             break;
1905     }
1906 
1907     if (gatt_client != NULL) {
1908         gatt_client_handle_att_response(gatt_client, packet, size);
1909         gatt_client_run();
1910     }
1911 }
1912 
1913 #ifdef ENABLE_LE_SIGNED_WRITE
1914 static void att_signed_write_handle_cmac_result(uint8_t hash[8]){
1915     btstack_linked_list_iterator_t it;
1916     btstack_linked_list_iterator_init(&it, &gatt_client_connections);
1917     while (btstack_linked_list_iterator_has_next(&it)){
1918         gatt_client_t * gatt_client = (gatt_client_t *) btstack_linked_list_iterator_next(&it);
1919         if (gatt_client->gatt_client_state == P_W4_CMAC_RESULT){
1920             // store result
1921             (void)memcpy(gatt_client->cmac, hash, 8);
1922             // reverse_64(hash, gatt_client->cmac);
1923             gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1924             gatt_client_run();
1925             return;
1926         }
1927     }
1928 }
1929 
1930 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){
1931     gatt_client_t * gatt_client;
1932     uint8_t status = gatt_client_provide_context_for_handle(con_handle, &gatt_client);
1933     if (status != ERROR_CODE_SUCCESS){
1934         return status;
1935     }
1936     if (is_ready(gatt_client) == 0){
1937         return GATT_CLIENT_IN_WRONG_STATE;
1938     }
1939 
1940     gatt_client->callback = callback;
1941     gatt_client->attribute_handle = value_handle;
1942     gatt_client->attribute_length = message_len;
1943     gatt_client->attribute_value = message;
1944     gatt_client->gatt_client_state = P_W4_IDENTITY_RESOLVING;
1945     gatt_client_run();
1946     return ERROR_CODE_SUCCESS;
1947 }
1948 #endif
1949 
1950 uint8_t gatt_client_discover_primary_services(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
1951     gatt_client_t * gatt_client;
1952     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
1953     if (status != ERROR_CODE_SUCCESS){
1954         return status;
1955     }
1956     if (is_ready(gatt_client) == 0){
1957         return GATT_CLIENT_IN_WRONG_STATE;
1958     }
1959 
1960     gatt_client->callback = callback;
1961     gatt_client->start_group_handle = 0x0001;
1962     gatt_client->end_group_handle   = 0xffff;
1963     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_QUERY;
1964     gatt_client->uuid16 = GATT_PRIMARY_SERVICE_UUID;
1965     gatt_client_run();
1966     return ERROR_CODE_SUCCESS;
1967 }
1968 
1969 uint8_t gatt_client_discover_secondary_services(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
1970     gatt_client_t * gatt_client;
1971     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
1972     if (status != ERROR_CODE_SUCCESS){
1973         return status;
1974     }
1975     if (is_ready(gatt_client) == 0){
1976         return GATT_CLIENT_IN_WRONG_STATE;
1977     }
1978 
1979     gatt_client->callback = callback;
1980     gatt_client->start_group_handle = 0x0001;
1981     gatt_client->end_group_handle   = 0xffff;
1982     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_QUERY;
1983     gatt_client->uuid16 = GATT_SECONDARY_SERVICE_UUID;
1984     gatt_client_run();
1985     return ERROR_CODE_SUCCESS;
1986 }
1987 
1988 uint8_t gatt_client_discover_primary_services_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t uuid16){
1989     gatt_client_t * gatt_client;
1990     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
1991     if (status != ERROR_CODE_SUCCESS){
1992         return status;
1993     }
1994     if (is_ready(gatt_client) == 0){
1995         return GATT_CLIENT_IN_WRONG_STATE;
1996     }
1997 
1998     gatt_client->callback = callback;
1999     gatt_client->start_group_handle = 0x0001;
2000     gatt_client->end_group_handle   = 0xffff;
2001     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
2002     gatt_client->uuid16 = uuid16;
2003     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), gatt_client->uuid16);
2004     gatt_client_run();
2005     return ERROR_CODE_SUCCESS;
2006 }
2007 
2008 uint8_t gatt_client_discover_primary_services_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, const uint8_t * uuid128){
2009     gatt_client_t * gatt_client;
2010     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2011     if (status != ERROR_CODE_SUCCESS){
2012         return status;
2013     }
2014     if (is_ready(gatt_client) == 0){
2015         return GATT_CLIENT_IN_WRONG_STATE;
2016     }
2017 
2018     gatt_client->callback = callback;
2019     gatt_client->start_group_handle = 0x0001;
2020     gatt_client->end_group_handle   = 0xffff;
2021     gatt_client->uuid16 = 0;
2022     (void)memcpy(gatt_client->uuid128, uuid128, 16);
2023     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
2024     gatt_client_run();
2025     return ERROR_CODE_SUCCESS;
2026 }
2027 
2028 uint8_t gatt_client_discover_characteristics_for_service(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t * service){
2029     gatt_client_t * gatt_client;
2030     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2031     if (status != ERROR_CODE_SUCCESS){
2032         return status;
2033     }
2034     if (is_ready(gatt_client) == 0){
2035         return GATT_CLIENT_IN_WRONG_STATE;
2036     }
2037 
2038     gatt_client->callback = callback;
2039     gatt_client->start_group_handle = service->start_group_handle;
2040     gatt_client->end_group_handle   = service->end_group_handle;
2041     gatt_client->filter_with_uuid = 0;
2042     gatt_client->characteristic_start_handle = 0;
2043     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY;
2044     gatt_client_run();
2045     return ERROR_CODE_SUCCESS;
2046 }
2047 
2048 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){
2049     gatt_client_t * gatt_client;
2050     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2051     if (status != ERROR_CODE_SUCCESS){
2052         return status;
2053     }
2054     if (is_ready(gatt_client) == 0){
2055         return GATT_CLIENT_IN_WRONG_STATE;
2056     }
2057     gatt_client->callback = callback;
2058     gatt_client->start_group_handle = service->start_group_handle;
2059     gatt_client->end_group_handle   = service->end_group_handle;
2060     gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_QUERY;
2061 
2062     gatt_client_run();
2063     return ERROR_CODE_SUCCESS;
2064 }
2065 
2066 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){
2067     gatt_client_t * gatt_client;
2068     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2069     if (status != ERROR_CODE_SUCCESS){
2070         return status;
2071     }
2072     if (is_ready(gatt_client) == 0){
2073         return GATT_CLIENT_IN_WRONG_STATE;
2074     }
2075 
2076     gatt_client->callback = callback;
2077     gatt_client->start_group_handle = start_handle;
2078     gatt_client->end_group_handle   = end_handle;
2079     gatt_client->filter_with_uuid = 1;
2080     gatt_client->uuid16 = uuid16;
2081     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
2082     gatt_client->characteristic_start_handle = 0;
2083     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
2084     gatt_client_run();
2085     return ERROR_CODE_SUCCESS;
2086 }
2087 
2088 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){
2089     gatt_client_t * gatt_client;
2090     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2091     if (status != ERROR_CODE_SUCCESS){
2092         return status;
2093     }
2094     if (is_ready(gatt_client) == 0){
2095         return GATT_CLIENT_IN_WRONG_STATE;
2096     }
2097 
2098     gatt_client->callback = callback;
2099     gatt_client->start_group_handle = start_handle;
2100     gatt_client->end_group_handle   = end_handle;
2101     gatt_client->filter_with_uuid = 1;
2102     gatt_client->uuid16 = 0;
2103     (void)memcpy(gatt_client->uuid128, uuid128, 16);
2104     gatt_client->characteristic_start_handle = 0;
2105     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
2106     gatt_client_run();
2107     return ERROR_CODE_SUCCESS;
2108 }
2109 
2110 
2111 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){
2112     return gatt_client_discover_characteristics_for_handle_range_by_uuid16(callback, con_handle, service->start_group_handle, service->end_group_handle, uuid16);
2113 }
2114 
2115 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){
2116     return gatt_client_discover_characteristics_for_handle_range_by_uuid128(callback, con_handle, service->start_group_handle, service->end_group_handle, uuid128);
2117 }
2118 
2119 uint8_t gatt_client_discover_characteristic_descriptors(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t * characteristic){
2120     gatt_client_t * gatt_client;
2121     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2122     if (status != ERROR_CODE_SUCCESS){
2123         return status;
2124     }
2125     if (is_ready(gatt_client) == 0){
2126         return GATT_CLIENT_IN_WRONG_STATE;
2127     }
2128 
2129     if (characteristic->value_handle == characteristic->end_handle){
2130         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
2131         return ERROR_CODE_SUCCESS;
2132     }
2133     gatt_client->callback = callback;
2134     gatt_client->start_group_handle = characteristic->value_handle + 1u;
2135     gatt_client->end_group_handle   = characteristic->end_handle;
2136     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY;
2137     gatt_client_run();
2138     return ERROR_CODE_SUCCESS;
2139 }
2140 
2141 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){
2142     gatt_client_t * gatt_client;
2143     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2144     if (status != ERROR_CODE_SUCCESS){
2145         return status;
2146     }
2147     if (is_ready(gatt_client) == 0){
2148         return GATT_CLIENT_IN_WRONG_STATE;
2149     }
2150 
2151     gatt_client->callback = callback;
2152     gatt_client->attribute_handle = value_handle;
2153     gatt_client->attribute_offset = 0;
2154     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY;
2155     gatt_client_run();
2156     return ERROR_CODE_SUCCESS;
2157 }
2158 
2159 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){
2160     gatt_client_t * gatt_client;
2161     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2162     if (status != ERROR_CODE_SUCCESS){
2163         return status;
2164     }
2165     if (is_ready(gatt_client) == 0){
2166         return GATT_CLIENT_IN_WRONG_STATE;
2167     }
2168 
2169     gatt_client->callback = callback;
2170     gatt_client->start_group_handle = start_handle;
2171     gatt_client->end_group_handle = end_handle;
2172     gatt_client->query_start_handle = start_handle;
2173     gatt_client->query_end_handle = end_handle;
2174     gatt_client->uuid16 = uuid16;
2175     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
2176     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
2177     gatt_client_run();
2178     return ERROR_CODE_SUCCESS;
2179 }
2180 
2181 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){
2182     gatt_client_t * gatt_client;
2183     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2184     if (status != ERROR_CODE_SUCCESS){
2185         return status;
2186     }
2187     if (is_ready(gatt_client) == 0){
2188         return GATT_CLIENT_IN_WRONG_STATE;
2189     }
2190 
2191     gatt_client->callback = callback;
2192     gatt_client->start_group_handle = start_handle;
2193     gatt_client->end_group_handle = end_handle;
2194     gatt_client->query_start_handle = start_handle;
2195     gatt_client->query_end_handle = end_handle;
2196     gatt_client->uuid16 = 0;
2197     (void)memcpy(gatt_client->uuid128, uuid128, 16);
2198     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
2199     gatt_client_run();
2200     return ERROR_CODE_SUCCESS;
2201 }
2202 
2203 
2204 uint8_t gatt_client_read_value_of_characteristic(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t * characteristic){
2205     return gatt_client_read_value_of_characteristic_using_value_handle(callback, con_handle, characteristic->value_handle);
2206 }
2207 
2208 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){
2209     gatt_client_t * gatt_client;
2210     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2211     if (status != ERROR_CODE_SUCCESS){
2212         return status;
2213     }
2214     if (is_ready(gatt_client) == 0){
2215         return GATT_CLIENT_IN_WRONG_STATE;
2216     }
2217 
2218     gatt_client->callback = callback;
2219     gatt_client->attribute_handle = value_handle;
2220     gatt_client->attribute_offset = offset;
2221     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
2222     gatt_client_run();
2223     return ERROR_CODE_SUCCESS;
2224 }
2225 
2226 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){
2227     return gatt_client_read_long_value_of_characteristic_using_value_handle_with_offset(callback, con_handle, value_handle, 0);
2228 }
2229 
2230 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){
2231     return gatt_client_read_long_value_of_characteristic_using_value_handle(callback, con_handle, characteristic->value_handle);
2232 }
2233 
2234 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){
2235     gatt_client_t * gatt_client;
2236     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2237     if (status != ERROR_CODE_SUCCESS){
2238         return status;
2239     }
2240     if (is_ready(gatt_client) == 0){
2241         return GATT_CLIENT_IN_WRONG_STATE;
2242     }
2243 
2244     gatt_client->callback = callback;
2245     gatt_client->read_multiple_handle_count = num_value_handles;
2246     gatt_client->read_multiple_handles = value_handles;
2247     gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
2248     gatt_client_run();
2249     return ERROR_CODE_SUCCESS;
2250 }
2251 
2252 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){
2253     gatt_client_t * gatt_client;
2254     uint8_t status = gatt_client_provide_context_for_handle(con_handle, &gatt_client);
2255     if (status != ERROR_CODE_SUCCESS){
2256         return status;
2257     }
2258 
2259     if (value_length > (gatt_client->mtu - 3u)) return GATT_CLIENT_VALUE_TOO_LONG;
2260     if (!att_dispatch_client_can_send_now(gatt_client->con_handle)) return GATT_CLIENT_BUSY;
2261 
2262     return att_write_request(gatt_client, ATT_WRITE_COMMAND, value_handle, value_length, value);
2263 }
2264 
2265 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){
2266     gatt_client_t * gatt_client;
2267     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2268     if (status != ERROR_CODE_SUCCESS){
2269         return status;
2270     }
2271     if (is_ready(gatt_client) == 0){
2272         return GATT_CLIENT_IN_WRONG_STATE;
2273     }
2274 
2275     gatt_client->callback = callback;
2276     gatt_client->attribute_handle = value_handle;
2277     gatt_client->attribute_length = value_length;
2278     gatt_client->attribute_value = value;
2279     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
2280     gatt_client_run();
2281     return ERROR_CODE_SUCCESS;
2282 }
2283 
2284 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){
2285     gatt_client_t * gatt_client;
2286     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2287     if (status != ERROR_CODE_SUCCESS){
2288         return status;
2289     }
2290     if (is_ready(gatt_client) == 0){
2291         return GATT_CLIENT_IN_WRONG_STATE;
2292     }
2293 
2294     gatt_client->callback = callback;
2295     gatt_client->attribute_handle = value_handle;
2296     gatt_client->attribute_length = value_length;
2297     gatt_client->attribute_offset = offset;
2298     gatt_client->attribute_value = value;
2299     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
2300     gatt_client_run();
2301     return ERROR_CODE_SUCCESS;
2302 }
2303 
2304 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){
2305     return gatt_client_write_long_value_of_characteristic_with_offset(callback, con_handle, value_handle, 0, value_length, value);
2306 }
2307 
2308 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){
2309     gatt_client_t * gatt_client;
2310     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2311     if (status != ERROR_CODE_SUCCESS){
2312         return status;
2313     }
2314     if (is_ready(gatt_client) == 0){
2315         return GATT_CLIENT_IN_WRONG_STATE;
2316     }
2317 
2318     gatt_client->callback = callback;
2319     gatt_client->attribute_handle = value_handle;
2320     gatt_client->attribute_length = value_length;
2321     gatt_client->attribute_offset = 0;
2322     gatt_client->attribute_value = value;
2323     gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
2324     gatt_client_run();
2325     return ERROR_CODE_SUCCESS;
2326 }
2327 
2328 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){
2329     gatt_client_t * gatt_client;
2330     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2331     if (status != ERROR_CODE_SUCCESS){
2332         return status;
2333     }
2334     if (is_ready(gatt_client) == 0){
2335         return GATT_CLIENT_IN_WRONG_STATE;
2336     }
2337 
2338     if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION) &&
2339         ((characteristic->properties & ATT_PROPERTY_NOTIFY) == 0u)) {
2340         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED");
2341         return GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED;
2342     } else if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_INDICATION) &&
2343                ((characteristic->properties & ATT_PROPERTY_INDICATE) == 0u)){
2344         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED");
2345         return GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED;
2346     }
2347 
2348     gatt_client->callback = callback;
2349     gatt_client->start_group_handle = characteristic->value_handle;
2350     gatt_client->end_group_handle = characteristic->end_handle;
2351     little_endian_store_16(gatt_client->client_characteristic_configuration_value, 0, configuration);
2352 
2353 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
2354     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
2355 #else
2356     gatt_client->gatt_client_state = P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
2357 #endif
2358     gatt_client_run();
2359     return ERROR_CODE_SUCCESS;
2360 }
2361 
2362 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){
2363     gatt_client_t * gatt_client;
2364     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2365     if (status != ERROR_CODE_SUCCESS){
2366         return status;
2367     }
2368     if (is_ready(gatt_client) == 0){
2369         return GATT_CLIENT_IN_WRONG_STATE;
2370     }
2371 
2372     gatt_client->callback = callback;
2373     gatt_client->attribute_handle = descriptor_handle;
2374 
2375     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
2376     gatt_client_run();
2377     return ERROR_CODE_SUCCESS;
2378 }
2379 
2380 uint8_t gatt_client_read_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t * descriptor){
2381     return gatt_client_read_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
2382 }
2383 
2384 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){
2385     gatt_client_t * gatt_client;
2386     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2387     if (status != ERROR_CODE_SUCCESS){
2388         return status;
2389     }
2390     if (is_ready(gatt_client) == 0){
2391         return GATT_CLIENT_IN_WRONG_STATE;
2392     }
2393 
2394     gatt_client->callback = callback;
2395     gatt_client->attribute_handle = descriptor_handle;
2396     gatt_client->attribute_offset = offset;
2397     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
2398     gatt_client_run();
2399     return ERROR_CODE_SUCCESS;
2400 }
2401 
2402 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){
2403     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0);
2404 }
2405 
2406 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){
2407     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
2408 }
2409 
2410 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){
2411     gatt_client_t * gatt_client;
2412     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2413     if (status != ERROR_CODE_SUCCESS){
2414         return status;
2415     }
2416     if (is_ready(gatt_client) == 0){
2417         return GATT_CLIENT_IN_WRONG_STATE;
2418     }
2419 
2420     gatt_client->callback = callback;
2421     gatt_client->attribute_handle = descriptor_handle;
2422     gatt_client->attribute_length = value_length;
2423     gatt_client->attribute_offset = 0;
2424     gatt_client->attribute_value = value;
2425     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
2426     gatt_client_run();
2427     return ERROR_CODE_SUCCESS;
2428 }
2429 
2430 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){
2431     return gatt_client_write_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, value_length, value);
2432 }
2433 
2434 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){
2435     gatt_client_t * gatt_client;
2436     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2437     if (status != ERROR_CODE_SUCCESS){
2438         return status;
2439     }
2440     if (is_ready(gatt_client) == 0){
2441         return GATT_CLIENT_IN_WRONG_STATE;
2442     }
2443 
2444     gatt_client->callback = callback;
2445     gatt_client->attribute_handle = descriptor_handle;
2446     gatt_client->attribute_length = value_length;
2447     gatt_client->attribute_offset = offset;
2448     gatt_client->attribute_value = value;
2449     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
2450     gatt_client_run();
2451     return ERROR_CODE_SUCCESS;
2452 }
2453 
2454 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){
2455     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0, value_length, value);
2456 }
2457 
2458 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){
2459     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, value_length, value);
2460 }
2461 
2462 /**
2463  * @brief -> gatt complete event
2464  */
2465 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){
2466     gatt_client_t * gatt_client;
2467     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2468     if (status != ERROR_CODE_SUCCESS){
2469         return status;
2470     }
2471     if (is_ready(gatt_client) == 0){
2472         return GATT_CLIENT_IN_WRONG_STATE;
2473     }
2474 
2475     gatt_client->callback = callback;
2476     gatt_client->attribute_handle = attribute_handle;
2477     gatt_client->attribute_length = value_length;
2478     gatt_client->attribute_offset = offset;
2479     gatt_client->attribute_value = value;
2480     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
2481     gatt_client_run();
2482     return ERROR_CODE_SUCCESS;
2483 }
2484 
2485 /**
2486  * @brief -> gatt complete event
2487  */
2488 uint8_t gatt_client_execute_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2489     gatt_client_t * gatt_client;
2490     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2491     if (status != ERROR_CODE_SUCCESS){
2492         return status;
2493     }
2494     if (is_ready(gatt_client) == 0){
2495         return GATT_CLIENT_IN_WRONG_STATE;
2496     }
2497 
2498     gatt_client->callback = callback;
2499     gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
2500     gatt_client_run();
2501     return ERROR_CODE_SUCCESS;
2502 }
2503 
2504 /**
2505  * @brief -> gatt complete event
2506  */
2507 uint8_t gatt_client_cancel_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2508     gatt_client_t * gatt_client;
2509     uint8_t status = gatt_client_provide_context_for_handle_and_start_timer(con_handle, &gatt_client);
2510     if (status != ERROR_CODE_SUCCESS){
2511         return status;
2512     }
2513     if (is_ready(gatt_client) == 0){
2514         return GATT_CLIENT_IN_WRONG_STATE;
2515     }
2516 
2517     gatt_client->callback = callback;
2518     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
2519     gatt_client_run();
2520     return ERROR_CODE_SUCCESS;
2521 }
2522 
2523 void gatt_client_deserialize_service(const uint8_t *packet, int offset, gatt_client_service_t * service){
2524     service->start_group_handle = little_endian_read_16(packet, offset);
2525     service->end_group_handle = little_endian_read_16(packet, offset + 2);
2526     reverse_128(&packet[offset + 4], service->uuid128);
2527     if (uuid_has_bluetooth_prefix(service->uuid128)){
2528         service->uuid16 = big_endian_read_32(service->uuid128, 0);
2529     } else {
2530         service->uuid16 = 0;
2531     }
2532 }
2533 
2534 void gatt_client_deserialize_characteristic(const uint8_t * packet, int offset, gatt_client_characteristic_t * characteristic){
2535     characteristic->start_handle = little_endian_read_16(packet, offset);
2536     characteristic->value_handle = little_endian_read_16(packet, offset + 2);
2537     characteristic->end_handle = little_endian_read_16(packet, offset + 4);
2538     characteristic->properties = little_endian_read_16(packet, offset + 6);
2539     reverse_128(&packet[offset+8], characteristic->uuid128);
2540     if (uuid_has_bluetooth_prefix(characteristic->uuid128)){
2541         characteristic->uuid16 = big_endian_read_32(characteristic->uuid128, 0);
2542     } else {
2543         characteristic->uuid16 = 0;
2544     }
2545 }
2546 
2547 void gatt_client_deserialize_characteristic_descriptor(const uint8_t * packet, int offset, gatt_client_characteristic_descriptor_t * descriptor){
2548     descriptor->handle = little_endian_read_16(packet, offset);
2549     reverse_128(&packet[offset+2], descriptor->uuid128);
2550     if (uuid_has_bluetooth_prefix(descriptor->uuid128)){
2551         descriptor->uuid16 = big_endian_read_32(descriptor->uuid128, 0);
2552     } else {
2553         descriptor->uuid16 = 0;
2554     }
2555 }
2556 
2557 void gatt_client_send_mtu_negotiation(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2558     gatt_client_t * gatt_client;
2559     uint8_t status = gatt_client_provide_context_for_handle(con_handle, &gatt_client);
2560     if (status != ERROR_CODE_SUCCESS){
2561         return;
2562     }
2563     if (gatt_client->mtu_state == MTU_AUTO_EXCHANGE_DISABLED){
2564         gatt_client->callback = callback;
2565         gatt_client->mtu_state = SEND_MTU_EXCHANGE;
2566         gatt_client_run();
2567     }
2568 }
2569 
2570 uint8_t gatt_client_request_to_write_without_response(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){
2571     gatt_client_t * gatt_client;
2572     uint8_t status = gatt_client_provide_context_for_handle(con_handle, &gatt_client);
2573     if (status != ERROR_CODE_SUCCESS){
2574         return status;
2575     }
2576     bool added = btstack_linked_list_add_tail(&gatt_client->write_without_response_requests, (btstack_linked_item_t*) callback_registration);
2577     att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
2578     if (added){
2579         return ERROR_CODE_SUCCESS;
2580     } else {
2581         return ERROR_CODE_COMMAND_DISALLOWED;
2582     }
2583 }
2584 
2585 uint8_t gatt_client_request_to_send_gatt_query(btstack_context_callback_registration_t * callback_registration, hci_con_handle_t con_handle){
2586     gatt_client_t * gatt_client;
2587     uint8_t status = gatt_client_provide_context_for_handle(con_handle, &gatt_client);
2588     if (status != ERROR_CODE_SUCCESS){
2589         return status;
2590     }
2591     bool added = btstack_linked_list_add_tail(&gatt_client->query_requests, (btstack_linked_item_t*) callback_registration);
2592     gatt_client_notify_can_send_query(gatt_client);
2593     if (added){
2594         return ERROR_CODE_SUCCESS;
2595     } else {
2596         return ERROR_CODE_COMMAND_DISALLOWED;
2597     }
2598 }
2599 
2600 uint8_t gatt_client_request_can_write_without_response_event(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2601     gatt_client_t * gatt_client;
2602     uint8_t status = gatt_client_provide_context_for_handle(con_handle, &gatt_client);
2603     if (status != ERROR_CODE_SUCCESS){
2604         return status;
2605     }
2606     if (gatt_client->write_without_response_callback != NULL){
2607         return GATT_CLIENT_IN_WRONG_STATE;
2608     }
2609     gatt_client->write_without_response_callback = callback;
2610     att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
2611     return ERROR_CODE_SUCCESS;
2612 }
2613 
2614 #ifdef ENABLE_GATT_OVER_CLASSIC
2615 
2616 #include "hci_event.h"
2617 
2618 // single active SDP query
2619 static gatt_client_t * gatt_client_classic_active_sdp_query;
2620 
2621 // macos protocol descriptor list requires 16 bytes
2622 static uint8_t gatt_client_classic_sdp_buffer[32];
2623 
2624 static const hci_event_t gatt_client_connected = {
2625         GATT_EVENT_CONNECTED, 0, "1BH"
2626 };
2627 
2628 static gatt_client_t * gatt_client_get_context_for_classic_addr(bd_addr_t addr){
2629     btstack_linked_item_t *it;
2630     for (it = (btstack_linked_item_t *) gatt_client_connections; it != NULL; it = it->next){
2631         gatt_client_t * gatt_client = (gatt_client_t *) it;
2632         if (memcmp(gatt_client->addr, addr, 6) == 0){
2633             return gatt_client;
2634         }
2635     }
2636     return NULL;
2637 }
2638 
2639 static gatt_client_t * gatt_client_get_context_for_l2cap_cid(uint16_t l2cap_cid){
2640     btstack_linked_item_t *it;
2641     for (it = (btstack_linked_item_t *) gatt_client_connections; it != NULL; it = it->next){
2642         gatt_client_t * gatt_client = (gatt_client_t *) it;
2643         if (gatt_client->l2cap_cid == l2cap_cid){
2644             return gatt_client;
2645         }
2646     }
2647     return NULL;
2648 }
2649 
2650 static void gatt_client_classic_handle_connected(gatt_client_t * gatt_client, uint8_t status){
2651     bd_addr_t addr;
2652     memcpy(addr, gatt_client->addr, 6);
2653     hci_con_handle_t con_handle = gatt_client->con_handle;
2654     btstack_packet_handler_t callback = gatt_client->callback;
2655     if (status != ERROR_CODE_SUCCESS){
2656         btstack_linked_list_remove(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
2657         btstack_memory_gatt_client_free(gatt_client);
2658     }
2659     uint8_t buffer[20];
2660     uint16_t len = hci_event_create_from_template_and_arguments(buffer, sizeof(buffer), &gatt_client_connected, status, addr,
2661                                                                 con_handle);
2662     (*callback)(HCI_EVENT_PACKET, 0, buffer, len);
2663 }
2664 
2665 static void gatt_client_l2cap_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
2666     gatt_client_t * gatt_client = NULL;
2667     uint8_t status;
2668     switch (packet_type){
2669         case HCI_EVENT_PACKET:
2670             switch (hci_event_packet_get_type(packet)) {
2671                 case L2CAP_EVENT_CHANNEL_OPENED:
2672                     status = l2cap_event_channel_opened_get_status(packet);
2673                     gatt_client = gatt_client_get_context_for_l2cap_cid(l2cap_event_channel_opened_get_local_cid(packet));
2674                     btstack_assert(gatt_client != NULL);
2675                     gatt_client->con_handle = l2cap_event_channel_opened_get_handle(packet);
2676                     gatt_client_classic_handle_connected(gatt_client, status);
2677                 case L2CAP_EVENT_CHANNEL_CLOSED:
2678                     // TODO:
2679                     break;
2680                 default:
2681                     break;
2682             }
2683             break;
2684         case L2CAP_DATA_PACKET:
2685             gatt_client = gatt_client_get_context_for_l2cap_cid(channel);
2686             gatt_client = gatt_client_get_context_for_l2cap_cid(l2cap_event_channel_opened_get_local_cid(packet));
2687             btstack_assert(gatt_client != NULL);
2688             log_info("l2cap data received");
2689             break;
2690     }
2691 }
2692 
2693 static void gatt_client_handle_sdp_client_query_attribute_value(gatt_client_t * connection, uint8_t *packet){
2694     des_iterator_t des_list_it;
2695     des_iterator_t prot_it;
2696 
2697     if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= sizeof(gatt_client_classic_sdp_buffer)) {
2698         gatt_client_classic_sdp_buffer[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
2699         if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
2700             switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
2701                 case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST:
2702                     for (des_iterator_init(&des_list_it, gatt_client_classic_sdp_buffer); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
2703                         uint8_t       *des_element;
2704                         uint8_t       *element;
2705                         uint32_t       uuid;
2706 
2707                         if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
2708 
2709                         des_element = des_iterator_get_element(&des_list_it);
2710                         des_iterator_init(&prot_it, des_element);
2711                         element = des_iterator_get_element(&prot_it);
2712 
2713                         if (de_get_element_type(element) != DE_UUID) continue;
2714 
2715                         uuid = de_get_uuid32(element);
2716                         des_iterator_next(&prot_it);
2717                         // we assume that the even if there are both roles supported, remote device uses the same psm and avdtp version for both
2718                         switch (uuid){
2719                             case BLUETOOTH_PROTOCOL_L2CAP:
2720                                 if (!des_iterator_has_more(&prot_it)) continue;
2721                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->l2cap_psm);
2722                                 break;
2723                             default:
2724                                 break;
2725                         }
2726                     }
2727                     break;
2728 
2729                 default:
2730                     break;
2731             }
2732         }
2733     }
2734 }
2735 
2736 static void gatt_client_classic_sdp_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
2737     gatt_client_t * gatt_client = gatt_client_classic_active_sdp_query;
2738     btstack_assert(gatt_client != NULL);
2739     uint8_t status;
2740 
2741     // TODO: handle sdp events, get l2cap psm
2742     switch (hci_event_packet_get_type(packet)){
2743         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
2744             gatt_client_handle_sdp_client_query_attribute_value(gatt_client, packet);
2745             // TODO:
2746             return;
2747         case SDP_EVENT_QUERY_COMPLETE:
2748             status = sdp_event_query_complete_get_status(packet);
2749             gatt_client_classic_active_sdp_query = NULL;
2750             log_info("l2cap psm: %0x, status %02x", gatt_client->l2cap_psm, status);
2751             if (status != ERROR_CODE_SUCCESS) break;
2752             if (gatt_client->l2cap_psm == 0) {
2753                 status = SDP_SERVICE_NOT_FOUND;
2754                 break;
2755             }
2756             break;
2757         default:
2758             btstack_assert(false);
2759             return;
2760     }
2761 
2762     // done
2763     if (status == ERROR_CODE_SUCCESS){
2764         gatt_client->gatt_client_state = P_W4_L2CAP_CONNECTION;
2765         status = l2cap_create_channel(gatt_client_l2cap_handler, gatt_client->addr, gatt_client->l2cap_psm, 0xffff,
2766                              &gatt_client->l2cap_cid);
2767     }
2768     if (status != ERROR_CODE_SUCCESS) {
2769         gatt_client_classic_handle_connected(gatt_client, status);
2770     }
2771 }
2772 
2773 static void gatt_client_classic_sdp_start(void * context){
2774     gatt_client_classic_active_sdp_query = (gatt_client_t *) context;
2775     gatt_client_classic_active_sdp_query->gatt_client_state = P_W4_SDP_QUERY;
2776     sdp_client_query_uuid16(gatt_client_classic_sdp_handler, gatt_client_classic_active_sdp_query->addr, ORG_BLUETOOTH_SERVICE_GENERIC_ATTRIBUTE);
2777 }
2778 
2779 uint8_t gatt_client_classic_connect(btstack_packet_handler_t callback, bd_addr_t addr){
2780     gatt_client_t * gatt_client = gatt_client_get_context_for_classic_addr(addr);
2781     if (gatt_client != NULL){
2782         return ERROR_CODE_ACL_CONNECTION_ALREADY_EXISTS;
2783     }
2784     gatt_client = btstack_memory_gatt_client_get();
2785     if (gatt_client == NULL){
2786         return ERROR_CODE_MEMORY_CAPACITY_EXCEEDED;
2787     }
2788     // init state
2789     gatt_client->con_handle = HCI_CON_HANDLE_INVALID;
2790     memcpy(gatt_client->addr, addr, 6);
2791     gatt_client->mtu = ATT_DEFAULT_MTU;
2792     gatt_client->security_level = LEVEL_0;
2793     if (gatt_client_mtu_exchange_enabled){
2794         gatt_client->mtu_state = SEND_MTU_EXCHANGE;
2795     } else {
2796         gatt_client->mtu_state = MTU_AUTO_EXCHANGE_DISABLED;
2797     }
2798     gatt_client->gatt_client_state = P_W2_SDP_QUERY;
2799     gatt_client->sdp_query_request.callback = &gatt_client_classic_sdp_start;
2800     gatt_client->sdp_query_request.context = gatt_client;
2801     gatt_client->callback = callback;
2802     btstack_linked_list_add(&gatt_client_connections, (btstack_linked_item_t*)gatt_client);
2803     sdp_client_register_query_callback(&gatt_client->sdp_query_request);
2804     return ERROR_CODE_COMMAND_DISALLOWED;
2805 }
2806 
2807 uint8_t gatt_client_classic_disconnect(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2808     gatt_client_t * gatt_client = gatt_client_get_context_for_handle(con_handle);
2809     if (gatt_client == NULL){
2810         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
2811     }
2812     gatt_client->callback = callback;
2813     return l2cap_disconnect(gatt_client->l2cap_cid);
2814 }
2815 #endif
2816 
2817 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
2818 void gatt_client_att_packet_handler_fuzz(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
2819     gatt_client_att_packet_handler(packet_type, handle, packet, size);
2820 }
2821 
2822 uint8_t gatt_client_get_client(hci_con_handle_t con_handle, gatt_client_t ** out_gatt_client){
2823     uint8_t status = gatt_client_provide_context_for_handle(con_handle, out_gatt_client);
2824     return status;
2825 }
2826 #endif
2827