xref: /btstack/src/ble/gatt_client.c (revision a95ca902cd90bf265920fd03950a8e680f62aea8)
1 /*
2  * Copyright (C) 2014 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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 "att_dispatch.h"
47 #include "ad_parser.h"
48 #include "ble/att_db.h"
49 #include "ble/core.h"
50 #include "ble/gatt_client.h"
51 #include "ble/le_device_db.h"
52 #include "ble/sm.h"
53 #include "btstack_debug.h"
54 #include "btstack_event.h"
55 #include "btstack_memory.h"
56 #include "btstack_run_loop.h"
57 #include "btstack_util.h"
58 #include "classic/sdp_util.h"
59 #include "hci.h"
60 #include "hci_cmd.h"
61 #include "hci_dump.h"
62 #include "l2cap.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     uint8_t 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 // @returns gatt_client context
159 // returns existing one, or tries to setup new one
160 static gatt_client_t * gatt_client_provide_context_for_handle(hci_con_handle_t con_handle){
161     gatt_client_t * gatt_client = gatt_client_get_context_for_handle(con_handle);
162     if (gatt_client) return gatt_client;
163 
164     // bail if no such hci connection
165     if (!hci_connection_for_handle(con_handle)){
166         log_error("No connection for handle 0x%04x", con_handle);
167         return NULL;
168     }
169     gatt_client = btstack_memory_gatt_client_get();
170     if (!gatt_client) return NULL;
171     // init state
172     gatt_client->con_handle = con_handle;
173     gatt_client->mtu = ATT_DEFAULT_MTU;
174     gatt_client->security_level = gatt_client_le_security_level_for_connection(con_handle);
175     if (gatt_client_mtu_exchange_enabled){
176         gatt_client->mtu_state = SEND_MTU_EXCHANGE;
177     } else {
178         gatt_client->mtu_state = MTU_AUTO_EXCHANGE_DISABLED;
179     }
180     gatt_client->gatt_client_state = P_READY;
181     btstack_linked_list_add(&gatt_client_connections, (btstack_linked_item_t*)gatt_client);
182     return gatt_client;
183 }
184 
185 static gatt_client_t * gatt_client_provide_context_for_handle_and_start_timer(hci_con_handle_t con_handle){
186     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
187     if (gatt_client == NULL) return NULL;
188     gatt_client_timeout_start(gatt_client);
189     return gatt_client;
190 }
191 
192 static int is_ready(gatt_client_t * gatt_client){
193     return gatt_client->gatt_client_state == P_READY;
194 }
195 
196 int gatt_client_is_ready(hci_con_handle_t con_handle){
197     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
198     if (gatt_client == NULL) return 0;
199     return is_ready(gatt_client);
200 }
201 
202 void gatt_client_mtu_enable_auto_negotiation(uint8_t enabled){
203     gatt_client_mtu_exchange_enabled = enabled != 0;
204 }
205 
206 uint8_t gatt_client_get_mtu(hci_con_handle_t con_handle, uint16_t * mtu){
207     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
208     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
209 
210     if ((gatt_client->mtu_state == MTU_EXCHANGED) || (gatt_client->mtu_state == MTU_AUTO_EXCHANGE_DISABLED)){
211         *mtu = gatt_client->mtu;
212         return ERROR_CODE_SUCCESS;
213     }
214     *mtu = ATT_DEFAULT_MTU;
215     return GATT_CLIENT_IN_WRONG_STATE;
216 }
217 
218 // precondition: can_send_packet_now == TRUE
219 static uint8_t att_confirmation(uint16_t con_handle){
220     l2cap_reserve_packet_buffer();
221     uint8_t * request = l2cap_get_outgoing_buffer();
222     request[0] = ATT_HANDLE_VALUE_CONFIRMATION;
223 
224     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 1);
225 }
226 
227 // precondition: can_send_packet_now == TRUE
228 static uint8_t att_find_information_request(uint16_t request_type, uint16_t con_handle, uint16_t start_handle, uint16_t end_handle){
229     l2cap_reserve_packet_buffer();
230     uint8_t * request = l2cap_get_outgoing_buffer();
231     request[0] = request_type;
232     little_endian_store_16(request, 1, start_handle);
233     little_endian_store_16(request, 3, end_handle);
234 
235     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 5);
236 }
237 
238 // precondition: can_send_packet_now == TRUE
239 static uint8_t att_find_by_type_value_request(uint16_t request_type, uint16_t attribute_group_type, uint16_t con_handle, uint16_t start_handle, uint16_t end_handle, uint8_t * value, uint16_t value_size){
240     l2cap_reserve_packet_buffer();
241     uint8_t * request = l2cap_get_outgoing_buffer();
242 
243     request[0] = request_type;
244     little_endian_store_16(request, 1, start_handle);
245     little_endian_store_16(request, 3, end_handle);
246     little_endian_store_16(request, 5, attribute_group_type);
247     (void)memcpy(&request[7], value, value_size);
248 
249     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 7u + value_size);
250 }
251 
252 // precondition: can_send_packet_now == TRUE
253 static uint8_t att_read_by_type_or_group_request_for_uuid16(uint16_t request_type, uint16_t uuid16, uint16_t con_handle, uint16_t start_handle, uint16_t end_handle){
254     l2cap_reserve_packet_buffer();
255     uint8_t * request = l2cap_get_outgoing_buffer();
256     request[0] = request_type;
257     little_endian_store_16(request, 1, start_handle);
258     little_endian_store_16(request, 3, end_handle);
259     little_endian_store_16(request, 5, uuid16);
260 
261     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 7);
262 }
263 
264 // precondition: can_send_packet_now == TRUE
265 static uint8_t att_read_by_type_or_group_request_for_uuid128(uint16_t request_type, uint8_t * uuid128, uint16_t con_handle, uint16_t start_handle, uint16_t end_handle){
266     l2cap_reserve_packet_buffer();
267     uint8_t * request = l2cap_get_outgoing_buffer();
268     request[0] = request_type;
269     little_endian_store_16(request, 1, start_handle);
270     little_endian_store_16(request, 3, end_handle);
271     reverse_128(uuid128, &request[5]);
272 
273     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 21);
274 }
275 
276 // precondition: can_send_packet_now == TRUE
277 static uint8_t att_read_request(uint16_t request_type, uint16_t con_handle, uint16_t attribute_handle){
278     l2cap_reserve_packet_buffer();
279     uint8_t * request = l2cap_get_outgoing_buffer();
280     request[0] = request_type;
281     little_endian_store_16(request, 1, attribute_handle);
282 
283     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 3);
284 }
285 
286 // precondition: can_send_packet_now == TRUE
287 static uint8_t att_read_blob_request(uint16_t request_type, uint16_t con_handle, uint16_t attribute_handle, uint16_t value_offset){
288     l2cap_reserve_packet_buffer();
289     uint8_t * request = l2cap_get_outgoing_buffer();
290     request[0] = request_type;
291     little_endian_store_16(request, 1, attribute_handle);
292     little_endian_store_16(request, 3, value_offset);
293 
294     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 5);
295 }
296 
297 static uint8_t att_read_multiple_request(uint16_t con_handle, uint16_t num_value_handles, uint16_t * value_handles){
298     l2cap_reserve_packet_buffer();
299     uint8_t * request = l2cap_get_outgoing_buffer();
300     request[0] = ATT_READ_MULTIPLE_REQUEST;
301     int i;
302     int offset = 1;
303     for (i=0;i<num_value_handles;i++){
304         little_endian_store_16(request, offset, value_handles[i]);
305         offset += 2;
306     }
307 
308     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, offset);
309 }
310 
311 #ifdef ENABLE_LE_SIGNED_WRITE
312 // precondition: can_send_packet_now == TRUE
313 static uint8_t att_signed_write_request(uint16_t request_type, uint16_t con_handle, uint16_t attribute_handle, uint16_t value_length, uint8_t * value, uint32_t sign_counter, uint8_t sgn[8]){
314     l2cap_reserve_packet_buffer();
315     uint8_t * request = l2cap_get_outgoing_buffer();
316     request[0] = request_type;
317     little_endian_store_16(request, 1, attribute_handle);
318     (void)memcpy(&request[3], value, value_length);
319     little_endian_store_32(request, 3 + value_length, sign_counter);
320     reverse_64(sgn, &request[3 + value_length + 4]);
321 
322     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 3 + value_length + 12);
323 }
324 #endif
325 
326 // precondition: can_send_packet_now == TRUE
327 static uint8_t att_write_request(uint16_t request_type, uint16_t con_handle, uint16_t attribute_handle, uint16_t value_length, uint8_t * value){
328     l2cap_reserve_packet_buffer();
329     uint8_t * request = l2cap_get_outgoing_buffer();
330     request[0] = request_type;
331     little_endian_store_16(request, 1, attribute_handle);
332     (void)memcpy(&request[3], value, value_length);
333 
334     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 3u + value_length);
335 }
336 
337 // precondition: can_send_packet_now == TRUE
338 static uint8_t att_execute_write_request(uint16_t request_type, uint16_t con_handle, uint8_t execute_write){
339     l2cap_reserve_packet_buffer();
340     uint8_t * request = l2cap_get_outgoing_buffer();
341     request[0] = request_type;
342     request[1] = execute_write;
343 
344     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 2);
345 }
346 
347 // precondition: can_send_packet_now == TRUE
348 static uint8_t att_prepare_write_request(uint16_t request_type, uint16_t con_handle, uint16_t attribute_handle, uint16_t value_offset, uint16_t blob_length, uint8_t * value){
349     l2cap_reserve_packet_buffer();
350     uint8_t * request = l2cap_get_outgoing_buffer();
351     request[0] = request_type;
352     little_endian_store_16(request, 1, attribute_handle);
353     little_endian_store_16(request, 3, value_offset);
354     (void)memcpy(&request[5], &value[value_offset], blob_length);
355 
356     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 5u + blob_length);
357 }
358 
359 static uint8_t att_exchange_mtu_request(uint16_t con_handle){
360     uint16_t mtu = l2cap_max_le_mtu();
361     l2cap_reserve_packet_buffer();
362     uint8_t * request = l2cap_get_outgoing_buffer();
363     request[0] = ATT_EXCHANGE_MTU_REQUEST;
364     little_endian_store_16(request, 1, mtu);
365 
366     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 3);
367 }
368 
369 static uint16_t write_blob_length(gatt_client_t * gatt_client){
370     uint16_t max_blob_length = gatt_client->mtu - 5u;
371     if (gatt_client->attribute_offset >= gatt_client->attribute_length) {
372         return 0;
373     }
374     uint16_t rest_length = gatt_client->attribute_length - gatt_client->attribute_offset;
375     if (max_blob_length > rest_length){
376         return rest_length;
377     }
378     return max_blob_length;
379 }
380 
381 static void send_gatt_services_request(gatt_client_t *gatt_client){
382     att_read_by_type_or_group_request_for_uuid16(ATT_READ_BY_GROUP_TYPE_REQUEST, GATT_PRIMARY_SERVICE_UUID, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle);
383 }
384 
385 static void send_gatt_by_uuid_request(gatt_client_t *gatt_client, uint16_t attribute_group_type){
386     if (gatt_client->uuid16){
387         uint8_t uuid16[2];
388         little_endian_store_16(uuid16, 0, gatt_client->uuid16);
389         att_find_by_type_value_request(ATT_FIND_BY_TYPE_VALUE_REQUEST, attribute_group_type, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle, uuid16, 2);
390         return;
391     }
392     uint8_t uuid128[16];
393     reverse_128(gatt_client->uuid128, uuid128);
394     att_find_by_type_value_request(ATT_FIND_BY_TYPE_VALUE_REQUEST, attribute_group_type, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle, uuid128, 16);
395 }
396 
397 static void send_gatt_services_by_uuid_request(gatt_client_t *gatt_client){
398     send_gatt_by_uuid_request(gatt_client, GATT_PRIMARY_SERVICE_UUID);
399 }
400 
401 static void send_gatt_included_service_uuid_request(gatt_client_t *gatt_client){
402     att_read_request(ATT_READ_REQUEST, gatt_client->con_handle, gatt_client->query_start_handle);
403 }
404 
405 static void send_gatt_included_service_request(gatt_client_t *gatt_client){
406     att_read_by_type_or_group_request_for_uuid16(ATT_READ_BY_TYPE_REQUEST, GATT_INCLUDE_SERVICE_UUID, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle);
407 }
408 
409 static void send_gatt_characteristic_request(gatt_client_t *gatt_client){
410     att_read_by_type_or_group_request_for_uuid16(ATT_READ_BY_TYPE_REQUEST, GATT_CHARACTERISTICS_UUID, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle);
411 }
412 
413 static void send_gatt_characteristic_descriptor_request(gatt_client_t *gatt_client){
414     att_find_information_request(ATT_FIND_INFORMATION_REQUEST, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle);
415 }
416 
417 static void send_gatt_read_characteristic_value_request(gatt_client_t *gatt_client){
418     att_read_request(ATT_READ_REQUEST, gatt_client->con_handle, gatt_client->attribute_handle);
419 }
420 
421 static void send_gatt_read_by_type_request(gatt_client_t * gatt_client){
422     if (gatt_client->uuid16){
423         att_read_by_type_or_group_request_for_uuid16(ATT_READ_BY_TYPE_REQUEST, gatt_client->uuid16, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle);
424     } else {
425         att_read_by_type_or_group_request_for_uuid128(ATT_READ_BY_TYPE_REQUEST, gatt_client->uuid128, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle);
426     }
427 }
428 
429 static void send_gatt_read_blob_request(gatt_client_t *gatt_client){
430     att_read_blob_request(ATT_READ_BLOB_REQUEST, gatt_client->con_handle, gatt_client->attribute_handle, gatt_client->attribute_offset);
431 }
432 
433 static void send_gatt_read_multiple_request(gatt_client_t * gatt_client){
434     att_read_multiple_request(gatt_client->con_handle, gatt_client->read_multiple_handle_count, gatt_client->read_multiple_handles);
435 }
436 
437 static void send_gatt_write_attribute_value_request(gatt_client_t * gatt_client){
438     att_write_request(ATT_WRITE_REQUEST, gatt_client->con_handle, gatt_client->attribute_handle, gatt_client->attribute_length, gatt_client->attribute_value);
439 }
440 
441 static void send_gatt_write_client_characteristic_configuration_request(gatt_client_t * gatt_client){
442     att_write_request(ATT_WRITE_REQUEST, gatt_client->con_handle, gatt_client->client_characteristic_configuration_handle, 2, gatt_client->client_characteristic_configuration_value);
443 }
444 
445 static void send_gatt_prepare_write_request(gatt_client_t * gatt_client){
446     att_prepare_write_request(ATT_PREPARE_WRITE_REQUEST, gatt_client->con_handle, gatt_client->attribute_handle, gatt_client->attribute_offset, write_blob_length(gatt_client), gatt_client->attribute_value);
447 }
448 
449 static void send_gatt_execute_write_request(gatt_client_t * gatt_client){
450     att_execute_write_request(ATT_EXECUTE_WRITE_REQUEST, gatt_client->con_handle, 1);
451 }
452 
453 static void send_gatt_cancel_prepared_write_request(gatt_client_t * gatt_client){
454     att_execute_write_request(ATT_EXECUTE_WRITE_REQUEST, gatt_client->con_handle, 0);
455 }
456 
457 #ifndef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
458 static void send_gatt_read_client_characteristic_configuration_request(gatt_client_t * gatt_client){
459     att_read_by_type_or_group_request_for_uuid16(ATT_READ_BY_TYPE_REQUEST, GATT_CLIENT_CHARACTERISTICS_CONFIGURATION, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle);
460 }
461 #endif
462 
463 static void send_gatt_read_characteristic_descriptor_request(gatt_client_t * gatt_client){
464     att_read_request(ATT_READ_REQUEST, gatt_client->con_handle, gatt_client->attribute_handle);
465 }
466 
467 #ifdef ENABLE_LE_SIGNED_WRITE
468 static void send_gatt_signed_write_request(gatt_client_t * gatt_client, uint32_t sign_counter){
469     att_signed_write_request(ATT_SIGNED_WRITE_COMMAND, gatt_client->con_handle, gatt_client->attribute_handle, gatt_client->attribute_length, gatt_client->attribute_value, sign_counter, gatt_client->cmac);
470 }
471 #endif
472 
473 static uint16_t get_last_result_handle_from_service_list(uint8_t * packet, uint16_t size){
474     uint8_t attr_length = packet[1];
475     return little_endian_read_16(packet, size - attr_length + 2u);
476 }
477 
478 static uint16_t get_last_result_handle_from_characteristics_list(uint8_t * packet, uint16_t size){
479     uint8_t attr_length = packet[1];
480     return little_endian_read_16(packet, size - attr_length + 3u);
481 }
482 
483 static uint16_t get_last_result_handle_from_included_services_list(uint8_t * packet, uint16_t size){
484     uint8_t attr_length = packet[1];
485     return little_endian_read_16(packet, size - attr_length);
486 }
487 
488 static void gatt_client_handle_transaction_complete(gatt_client_t * gatt_client){
489     gatt_client->gatt_client_state = P_READY;
490     gatt_client_timeout_stop(gatt_client);
491 }
492 
493 static void emit_event_new(btstack_packet_handler_t callback, uint8_t * packet, uint16_t size){
494     if (!callback) return;
495     hci_dump_packet(HCI_EVENT_PACKET, 0, packet, size);
496     (*callback)(HCI_EVENT_PACKET, 0, packet, size);
497 }
498 
499 void gatt_client_listen_for_characteristic_value_updates(gatt_client_notification_t * notification, btstack_packet_handler_t packet_handler, hci_con_handle_t con_handle, gatt_client_characteristic_t * characteristic){
500     notification->callback = packet_handler;
501     notification->con_handle = con_handle;
502     if (characteristic == NULL){
503         notification->attribute_handle = GATT_CLIENT_ANY_VALUE_HANDLE;
504     } else {
505         notification->attribute_handle = characteristic->value_handle;
506     }
507     btstack_linked_list_add(&gatt_client_value_listeners, (btstack_linked_item_t*) notification);
508 }
509 
510 void gatt_client_stop_listening_for_characteristic_value_updates(gatt_client_notification_t * notification){
511     btstack_linked_list_remove(&gatt_client_value_listeners, (btstack_linked_item_t*) notification);
512 }
513 
514 static void emit_event_to_registered_listeners(hci_con_handle_t con_handle, uint16_t attribute_handle, uint8_t * packet, uint16_t size){
515     btstack_linked_list_iterator_t it;
516     btstack_linked_list_iterator_init(&it, &gatt_client_value_listeners);
517     while (btstack_linked_list_iterator_has_next(&it)){
518         gatt_client_notification_t * notification = (gatt_client_notification_t*) btstack_linked_list_iterator_next(&it);
519         if ((notification->con_handle       != GATT_CLIENT_ANY_CONNECTION)   && (notification->con_handle       != con_handle)) continue;
520         if ((notification->attribute_handle != GATT_CLIENT_ANY_VALUE_HANDLE) && (notification->attribute_handle != attribute_handle)) continue;
521         (*notification->callback)(HCI_EVENT_PACKET, 0, packet, size);
522     }
523 }
524 
525 static void emit_gatt_complete_event(gatt_client_t * gatt_client, uint8_t att_status){
526     // @format H1
527     uint8_t packet[5];
528     packet[0] = GATT_EVENT_QUERY_COMPLETE;
529     packet[1] = 3;
530     little_endian_store_16(packet, 2, gatt_client->con_handle);
531     packet[4] = att_status;
532     emit_event_new(gatt_client->callback, packet, sizeof(packet));
533 }
534 
535 static void emit_gatt_service_query_result_event(gatt_client_t * gatt_client, uint16_t start_group_handle, uint16_t end_group_handle, uint8_t * uuid128){
536     // @format HX
537     uint8_t packet[24];
538     packet[0] = GATT_EVENT_SERVICE_QUERY_RESULT;
539     packet[1] = sizeof(packet) - 2u;
540     little_endian_store_16(packet, 2, gatt_client->con_handle);
541     ///
542     little_endian_store_16(packet, 4, start_group_handle);
543     little_endian_store_16(packet, 6, end_group_handle);
544     reverse_128(uuid128, &packet[8]);
545     emit_event_new(gatt_client->callback, packet, sizeof(packet));
546 }
547 
548 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, uint8_t * uuid128){
549     // @format HX
550     uint8_t packet[26];
551     packet[0] = GATT_EVENT_INCLUDED_SERVICE_QUERY_RESULT;
552     packet[1] = sizeof(packet) - 2u;
553     little_endian_store_16(packet, 2, gatt_client->con_handle);
554     ///
555     little_endian_store_16(packet, 4, include_handle);
556     //
557     little_endian_store_16(packet, 6, start_group_handle);
558     little_endian_store_16(packet, 8, end_group_handle);
559     reverse_128(uuid128, &packet[10]);
560     emit_event_new(gatt_client->callback, packet, sizeof(packet));
561 }
562 
563 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,
564                                                         uint16_t properties, uint8_t * uuid128){
565     // @format HY
566     uint8_t packet[28];
567     packet[0] = GATT_EVENT_CHARACTERISTIC_QUERY_RESULT;
568     packet[1] = sizeof(packet) - 2u;
569     little_endian_store_16(packet, 2, gatt_client->con_handle);
570     ///
571     little_endian_store_16(packet, 4,  start_handle);
572     little_endian_store_16(packet, 6,  value_handle);
573     little_endian_store_16(packet, 8,  end_handle);
574     little_endian_store_16(packet, 10, properties);
575     reverse_128(uuid128, &packet[12]);
576     emit_event_new(gatt_client->callback, packet, sizeof(packet));
577 }
578 
579 static void emit_gatt_all_characteristic_descriptors_result_event(
580         gatt_client_t * gatt_client, uint16_t descriptor_handle, uint8_t * uuid128){
581     // @format HZ
582     uint8_t packet[22];
583     packet[0] = GATT_EVENT_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT;
584     packet[1] = sizeof(packet) - 2u;
585     little_endian_store_16(packet, 2, gatt_client->con_handle);
586     ///
587     little_endian_store_16(packet, 4,  descriptor_handle);
588     reverse_128(uuid128, &packet[6]);
589     emit_event_new(gatt_client->callback, packet, sizeof(packet));
590 }
591 
592 static void emit_gatt_mtu_exchanged_result_event(gatt_client_t * gatt_client, uint16_t new_mtu){
593     // @format H2
594     uint8_t packet[6];
595     packet[0] = GATT_EVENT_MTU;
596     packet[1] = sizeof(packet) - 2u;
597     little_endian_store_16(packet, 2, gatt_client->con_handle);
598     little_endian_store_16(packet, 4, new_mtu);
599     att_dispatch_client_mtu_exchanged(gatt_client->con_handle, new_mtu);
600     emit_event_new(gatt_client->callback, packet, sizeof(packet));
601 }
602 ///
603 static void report_gatt_services(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size){
604     uint8_t attr_length = packet[1];
605     uint8_t uuid_length = attr_length - 4u;
606 
607     int i;
608     for (i = 2; i < size; i += attr_length){
609         uint16_t start_group_handle = little_endian_read_16(packet,i);
610         uint16_t end_group_handle   = little_endian_read_16(packet,i+2);
611         uint8_t  uuid128[16];
612         uint16_t uuid16 = 0;
613 
614         if (uuid_length == 2u){
615             uuid16 = little_endian_read_16(packet, i+4);
616             uuid_add_bluetooth_prefix((uint8_t*) &uuid128, uuid16);
617         } else {
618             reverse_128(&packet[i+4], uuid128);
619         }
620         emit_gatt_service_query_result_event(gatt_client, start_group_handle, end_group_handle, uuid128);
621     }
622 }
623 
624 // helper
625 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){
626     uint8_t uuid128[16];
627     uint16_t uuid16 = 0;
628     if (uuid_length == 2u){
629         uuid16 = little_endian_read_16(uuid, 0);
630         uuid_add_bluetooth_prefix((uint8_t*) uuid128, uuid16);
631     } else if (uuid_length == 16u){
632         reverse_128(uuid, uuid128);
633     } else {
634         return;
635     }
636 
637     if (gatt_client->filter_with_uuid && (memcmp(gatt_client->uuid128, uuid128, 16) != 0)) return;
638 
639     gatt_client->characteristic_properties = properties;
640     gatt_client->characteristic_start_handle = start_handle;
641     gatt_client->attribute_handle = value_handle;
642 
643     if (gatt_client->filter_with_uuid) return;
644 
645     gatt_client->uuid16 = uuid16;
646     (void)memcpy(gatt_client->uuid128, uuid128, 16);
647 }
648 
649 static void characteristic_end_found(gatt_client_t * gatt_client, uint16_t end_handle){
650     // TODO: stop searching if filter and uuid found
651 
652     if (!gatt_client->characteristic_start_handle) return;
653 
654     emit_gatt_characteristic_query_result_event(gatt_client, gatt_client->characteristic_start_handle, gatt_client->attribute_handle,
655                                                 end_handle, gatt_client->characteristic_properties, gatt_client->uuid128);
656 
657     gatt_client->characteristic_start_handle = 0;
658 }
659 
660 static void report_gatt_characteristics(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size){
661     if (size < 2u) return;
662     uint8_t attr_length = packet[1];
663     if ((attr_length != 7u) && (attr_length != 21u)) return;
664     uint8_t uuid_length = attr_length - 5u;
665     int i;
666     for (i = 2u; (i + attr_length) <= size; i += attr_length){
667         uint16_t start_handle = little_endian_read_16(packet, i);
668         uint8_t  properties = packet[i+2];
669         uint16_t value_handle = little_endian_read_16(packet, i+3);
670         characteristic_end_found(gatt_client, start_handle - 1u);
671         characteristic_start_found(gatt_client, start_handle, properties, value_handle, &packet[i + 5], uuid_length);
672     }
673 }
674 
675 static void report_gatt_included_service_uuid16(gatt_client_t * gatt_client, uint16_t include_handle, uint16_t uuid16){
676     uint8_t normalized_uuid128[16];
677     uuid_add_bluetooth_prefix(normalized_uuid128, uuid16);
678     emit_gatt_included_service_query_result_event(gatt_client, include_handle, gatt_client->query_start_handle,
679                                                   gatt_client->query_end_handle, normalized_uuid128);
680 }
681 
682 static void report_gatt_included_service_uuid128(gatt_client_t * gatt_client, uint16_t include_handle, uint8_t *uuid128){
683     emit_gatt_included_service_query_result_event(gatt_client, include_handle, gatt_client->query_start_handle,
684                                                   gatt_client->query_end_handle, uuid128);
685 }
686 
687 // @returns packet pointer
688 // @note assume that value is part of an l2cap buffer - overwrite HCI + L2CAP packet headers
689 static const int characteristic_value_event_header_size = 8;
690 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){
691 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
692     // avoid using pre ATT headers.
693     return NULL;
694 #endif
695     // before the value inside the ATT PDU
696     uint8_t * packet = value - characteristic_value_event_header_size;
697     packet[0] = type;
698     packet[1] = characteristic_value_event_header_size - 2 + length;
699     little_endian_store_16(packet, 2, con_handle);
700     little_endian_store_16(packet, 4, attribute_handle);
701     little_endian_store_16(packet, 6, length);
702     return packet;
703 }
704 
705 // @returns packet pointer
706 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
707 static const int long_characteristic_value_event_header_size = 10;
708 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){
709 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
710     // avoid using pre ATT headers.
711     return NULL;
712 #endif
713 #if defined(HCI_INCOMING_PRE_BUFFER_SIZE) && (HCI_INCOMING_PRE_BUFFER_SIZE >= 10 - 8) // L2CAP Header (4) - ACL Header (4)
714     // before the value inside the ATT PDU
715     uint8_t * packet = value - long_characteristic_value_event_header_size;
716     packet[0] = type;
717     packet[1] = long_characteristic_value_event_header_size - 2 + length;
718     little_endian_store_16(packet, 2, con_handle);
719     little_endian_store_16(packet, 4, attribute_handle);
720     little_endian_store_16(packet, 6, offset);
721     little_endian_store_16(packet, 8, length);
722     return packet;
723 #else
724     log_error("HCI_INCOMING_PRE_BUFFER_SIZE >= 2 required for long characteristic reads");
725     return NULL;
726 #endif
727 }
728 
729 // test if notification/indication should be delivered to application (BLESA)
730 static bool gatt_client_accept_server_message(hci_con_handle_t con_handle){
731 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION
732 	// ignore messages until re-encryption is complete
733     if (gap_reconnect_security_setup_active(con_handle)) return false;
734 
735 	// after that ignore if bonded but not encrypted
736 	return !gap_bonded(con_handle) || (gap_encryption_key_size(con_handle) > 0);
737 #else
738     UNUSED(con_handle);
739 	return true;
740 #endif
741 }
742 
743 
744 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
745 static void report_gatt_notification(hci_con_handle_t con_handle, uint16_t value_handle, uint8_t * value, int length){
746 	if (!gatt_client_accept_server_message(con_handle)) return;
747     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_NOTIFICATION, con_handle, value_handle, value, length);
748     emit_event_to_registered_listeners(con_handle, value_handle, packet, characteristic_value_event_header_size + length);
749 }
750 
751 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
752 static void report_gatt_indication(hci_con_handle_t con_handle, uint16_t value_handle, uint8_t * value, int length){
753 	if (!gatt_client_accept_server_message(con_handle)) return;
754     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_INDICATION, con_handle, value_handle, value, length);
755     emit_event_to_registered_listeners(con_handle, value_handle, packet, characteristic_value_event_header_size + length);
756 }
757 
758 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
759 static void report_gatt_characteristic_value(gatt_client_t * gatt_client, uint16_t attribute_handle, uint8_t * value, uint16_t length){
760     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT, gatt_client->con_handle, attribute_handle, value, length);
761     emit_event_new(gatt_client->callback, packet, characteristic_value_event_header_size + length);
762 }
763 
764 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
765 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){
766     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);
767     if (!packet) return;
768     emit_event_new(gatt_client->callback, packet, blob_length + long_characteristic_value_event_header_size);
769 }
770 
771 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){
772     UNUSED(value_offset);
773     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT, gatt_client->con_handle, descriptor_handle, value, value_length);
774     emit_event_new(gatt_client->callback, packet, value_length + 8u);
775 }
776 
777 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){
778     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);
779     if (!packet) return;
780     emit_event_new(gatt_client->callback, packet, blob_length + long_characteristic_value_event_header_size);
781 }
782 
783 static void report_gatt_all_characteristic_descriptors(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size, uint16_t pair_size){
784     int i;
785     for (i = 0u; (i + pair_size) <= size; i += pair_size){
786         uint16_t descriptor_handle = little_endian_read_16(packet,i);
787         uint8_t uuid128[16];
788         uint16_t uuid16 = 0;
789         if (pair_size == 4u){
790             uuid16 = little_endian_read_16(packet,i+2);
791             uuid_add_bluetooth_prefix(uuid128, uuid16);
792         } else {
793             reverse_128(&packet[i+2], uuid128);
794         }
795         emit_gatt_all_characteristic_descriptors_result_event(gatt_client, descriptor_handle, uuid128);
796     }
797 
798 }
799 
800 static int is_query_done(gatt_client_t * gatt_client, uint16_t last_result_handle){
801     return last_result_handle >= gatt_client->end_group_handle;
802 }
803 
804 static void trigger_next_query(gatt_client_t * gatt_client, uint16_t last_result_handle, gatt_client_state_t next_query_state){
805     if (is_query_done(gatt_client, last_result_handle)){
806         gatt_client_handle_transaction_complete(gatt_client);
807         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
808         return;
809     }
810     // next
811     gatt_client->start_group_handle = last_result_handle + 1u;
812     gatt_client->gatt_client_state = next_query_state;
813 }
814 
815 static void trigger_next_included_service_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
816     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_INCLUDED_SERVICE_QUERY);
817 }
818 
819 static void trigger_next_service_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
820     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_SERVICE_QUERY);
821 }
822 
823 static void trigger_next_service_by_uuid_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
824     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_SERVICE_WITH_UUID_QUERY);
825 }
826 
827 static void trigger_next_characteristic_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
828     if (is_query_done(gatt_client, last_result_handle)){
829         // report last characteristic
830         characteristic_end_found(gatt_client, gatt_client->end_group_handle);
831     }
832     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY);
833 }
834 
835 static void trigger_next_characteristic_descriptor_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
836     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY);
837 }
838 
839 static void trigger_next_read_by_type_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
840     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_READ_BY_TYPE_REQUEST);
841 }
842 
843 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){
844     gatt_client->attribute_offset += write_blob_length(gatt_client);
845     uint16_t next_blob_length =  write_blob_length(gatt_client);
846 
847     if (next_blob_length == 0u){
848         gatt_client->gatt_client_state = done_state;
849         return;
850     }
851     gatt_client->gatt_client_state = next_query_state;
852 }
853 
854 static void trigger_next_blob_query(gatt_client_t * gatt_client, gatt_client_state_t next_query_state, uint16_t received_blob_length){
855 
856     uint16_t max_blob_length = gatt_client->mtu - 1u;
857     if (received_blob_length < max_blob_length){
858         gatt_client_handle_transaction_complete(gatt_client);
859         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
860         return;
861     }
862 
863     gatt_client->attribute_offset += received_blob_length;
864     gatt_client->gatt_client_state = next_query_state;
865 }
866 
867 
868 static int is_value_valid(gatt_client_t *gatt_client, uint8_t *packet, uint16_t size){
869     uint16_t attribute_handle = little_endian_read_16(packet, 1);
870     uint16_t value_offset = little_endian_read_16(packet, 3);
871 
872     if (gatt_client->attribute_handle != attribute_handle) return 0;
873     if (gatt_client->attribute_offset != value_offset) return 0;
874     return memcmp(&gatt_client->attribute_value[gatt_client->attribute_offset], &packet[5], size - 5u) == 0u;
875 }
876 
877 // returns 1 if packet was sent
878 static int gatt_client_run_for_gatt_client(gatt_client_t * gatt_client){
879 
880     // wait until re-encryption as central is complete
881     if (gap_reconnect_security_setup_active(gatt_client->con_handle)) return 0;
882 
883     // wait until re-encryption complete
884     if (gatt_client->reencryption_active) return 0;
885 
886     if ((gatt_client->reencryption_result != ERROR_CODE_SUCCESS) && (gatt_client->gatt_client_state != P_READY)){
887 #ifndef ENABLE_LE_PROACTIVE_AUTHENTICATION
888         // re-encryption failed and we have a pending client request
889         // try to resolve it by deleting bonding information if we started pairing before
890         if (gatt_client->wait_for_pairing_complete){
891             // delete bonding information
892             int le_device_db_index = sm_le_device_index(gatt_client->con_handle);
893             btstack_assert(le_device_db_index >= 0);
894             hci_remove_le_device_db_entry_from_resolving_list((uint16_t) le_device_db_index);
895             le_device_db_remove(le_device_db_index);
896             // trigger pairing again
897             sm_request_pairing(gatt_client->con_handle);
898             return 0;
899         }
900 #endif
901         // report bonding information missing
902         gatt_client_handle_transaction_complete(gatt_client);
903         emit_gatt_complete_event(gatt_client, ATT_ERROR_BONDING_INFORMATION_MISSING);
904         return 0;
905     }
906 
907     // wait until pairing complete (either reactive authentication or due to required security level)
908     if (gatt_client->wait_for_pairing_complete) return 0;
909 
910     // verify security level
911     if (gatt_client_required_security_level > gatt_client->security_level){
912         log_info("Trigger pairing, current security level %u, required %u\n", gatt_client->security_level, gatt_client_required_security_level);
913         gatt_client->wait_for_pairing_complete = 1;
914         // set att error code for pairing failure based on required level
915         switch (gatt_client_required_security_level){
916             case LEVEL_4:
917             case LEVEL_3:
918                 gatt_client->pending_error_code = ATT_ERROR_INSUFFICIENT_AUTHENTICATION;
919                 break;
920             default:
921                 gatt_client->pending_error_code = ATT_ERROR_INSUFFICIENT_ENCRYPTION;
922                 break;
923         }
924         sm_request_pairing(gatt_client->con_handle);
925         // sm probably just sent a pdu
926         return 1;
927     }
928 
929     switch (gatt_client->mtu_state) {
930         case SEND_MTU_EXCHANGE:
931             gatt_client->mtu_state = SENT_MTU_EXCHANGE;
932             att_exchange_mtu_request(gatt_client->con_handle);
933             return 1;
934         case SENT_MTU_EXCHANGE:
935             return 0;
936         default:
937             break;
938     }
939 
940     if (gatt_client->send_confirmation){
941         gatt_client->send_confirmation = 0;
942         att_confirmation(gatt_client->con_handle);
943         return 1;
944     }
945 
946     // check MTU for writes
947     switch (gatt_client->gatt_client_state){
948         case P_W2_SEND_WRITE_CHARACTERISTIC_VALUE:
949         case P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR:
950             if (gatt_client->attribute_length <= (gatt_client->mtu - 3u)) break;
951             log_error("gatt_client_run: value len %u > MTU %u - 3\n", gatt_client->attribute_length,gatt_client->mtu);
952             gatt_client_handle_transaction_complete(gatt_client);
953             emit_gatt_complete_event(gatt_client, ATT_ERROR_INVALID_ATTRIBUTE_VALUE_LENGTH);
954             return 0;
955         default:
956             break;
957     }
958 
959     switch (gatt_client->gatt_client_state){
960         case P_W2_SEND_SERVICE_QUERY:
961             gatt_client->gatt_client_state = P_W4_SERVICE_QUERY_RESULT;
962             send_gatt_services_request(gatt_client);
963             return 1;
964 
965         case P_W2_SEND_SERVICE_WITH_UUID_QUERY:
966             gatt_client->gatt_client_state = P_W4_SERVICE_WITH_UUID_RESULT;
967             send_gatt_services_by_uuid_request(gatt_client);
968             return 1;
969 
970         case P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY:
971             gatt_client->gatt_client_state = P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT;
972             send_gatt_characteristic_request(gatt_client);
973             return 1;
974 
975         case P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY:
976             gatt_client->gatt_client_state = P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT;
977             send_gatt_characteristic_request(gatt_client);
978             return 1;
979 
980         case P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY:
981             gatt_client->gatt_client_state = P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT;
982             send_gatt_characteristic_descriptor_request(gatt_client);
983             return 1;
984 
985         case P_W2_SEND_INCLUDED_SERVICE_QUERY:
986             gatt_client->gatt_client_state = P_W4_INCLUDED_SERVICE_QUERY_RESULT;
987             send_gatt_included_service_request(gatt_client);
988             return 1;
989 
990         case P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY:
991             gatt_client->gatt_client_state = P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT;
992             send_gatt_included_service_uuid_request(gatt_client);
993             return 1;
994 
995         case P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY:
996             gatt_client->gatt_client_state = P_W4_READ_CHARACTERISTIC_VALUE_RESULT;
997             send_gatt_read_characteristic_value_request(gatt_client);
998             return 1;
999 
1000         case P_W2_SEND_READ_BLOB_QUERY:
1001             gatt_client->gatt_client_state = P_W4_READ_BLOB_RESULT;
1002             send_gatt_read_blob_request(gatt_client);
1003             return 1;
1004 
1005         case P_W2_SEND_READ_BY_TYPE_REQUEST:
1006             gatt_client->gatt_client_state = P_W4_READ_BY_TYPE_RESPONSE;
1007             send_gatt_read_by_type_request(gatt_client);
1008             return 1;
1009 
1010         case P_W2_SEND_READ_MULTIPLE_REQUEST:
1011             gatt_client->gatt_client_state = P_W4_READ_MULTIPLE_RESPONSE;
1012             send_gatt_read_multiple_request(gatt_client);
1013             return 1;
1014 
1015         case P_W2_SEND_WRITE_CHARACTERISTIC_VALUE:
1016             gatt_client->gatt_client_state = P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT;
1017             send_gatt_write_attribute_value_request(gatt_client);
1018             return 1;
1019 
1020         case P_W2_PREPARE_WRITE:
1021             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_RESULT;
1022             send_gatt_prepare_write_request(gatt_client);
1023             return 1;
1024 
1025         case P_W2_PREPARE_WRITE_SINGLE:
1026             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_SINGLE_RESULT;
1027             send_gatt_prepare_write_request(gatt_client);
1028             return 1;
1029 
1030         case P_W2_PREPARE_RELIABLE_WRITE:
1031             gatt_client->gatt_client_state = P_W4_PREPARE_RELIABLE_WRITE_RESULT;
1032             send_gatt_prepare_write_request(gatt_client);
1033             return 1;
1034 
1035         case P_W2_EXECUTE_PREPARED_WRITE:
1036             gatt_client->gatt_client_state = P_W4_EXECUTE_PREPARED_WRITE_RESULT;
1037             send_gatt_execute_write_request(gatt_client);
1038             return 1;
1039 
1040         case P_W2_CANCEL_PREPARED_WRITE:
1041             gatt_client->gatt_client_state = P_W4_CANCEL_PREPARED_WRITE_RESULT;
1042             send_gatt_cancel_prepared_write_request(gatt_client);
1043             return 1;
1044 
1045         case P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH:
1046             gatt_client->gatt_client_state = P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT;
1047             send_gatt_cancel_prepared_write_request(gatt_client);
1048             return 1;
1049 
1050 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1051         case P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY:
1052             // use Find Information
1053             gatt_client->gatt_client_state = P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT;
1054             send_gatt_characteristic_descriptor_request(gatt_client);
1055 #else
1056         case P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY:
1057             // Use Read By Type
1058             gatt_client->gatt_client_state = P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT;
1059             send_gatt_read_client_characteristic_configuration_request(gatt_client);
1060 #endif
1061             return 1;
1062 
1063         case P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY:
1064             gatt_client->gatt_client_state = P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT;
1065             send_gatt_read_characteristic_descriptor_request(gatt_client);
1066             return 1;
1067 
1068         case P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY:
1069             gatt_client->gatt_client_state = P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT;
1070             send_gatt_read_blob_request(gatt_client);
1071             return 1;
1072 
1073         case P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR:
1074             gatt_client->gatt_client_state = P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1075             send_gatt_write_attribute_value_request(gatt_client);
1076             return 1;
1077 
1078         case P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION:
1079             gatt_client->gatt_client_state = P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT;
1080             send_gatt_write_client_characteristic_configuration_request(gatt_client);
1081             return 1;
1082 
1083         case P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR:
1084             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1085             send_gatt_prepare_write_request(gatt_client);
1086             return 1;
1087 
1088         case P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR:
1089             gatt_client->gatt_client_state = P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1090             send_gatt_execute_write_request(gatt_client);
1091             return 1;
1092 
1093 #ifdef ENABLE_LE_SIGNED_WRITE
1094         case P_W4_IDENTITY_RESOLVING:
1095             log_info("P_W4_IDENTITY_RESOLVING - state %x", sm_identity_resolving_state(gatt_client->con_handle));
1096             switch (sm_identity_resolving_state(gatt_client->con_handle)){
1097                 case IRK_LOOKUP_SUCCEEDED:
1098                     gatt_client->le_device_index = sm_le_device_index(gatt_client->con_handle);
1099                     gatt_client->gatt_client_state = P_W4_CMAC_READY;
1100                     break;
1101                 case IRK_LOOKUP_FAILED:
1102                     gatt_client_handle_transaction_complete(gatt_client);
1103                     emit_gatt_complete_event(gatt_client, ATT_ERROR_BONDING_INFORMATION_MISSING);
1104                     return 0;
1105                 default:
1106                     return 0;
1107             }
1108 
1109             /* Fall through */
1110 
1111         case P_W4_CMAC_READY:
1112             if (sm_cmac_ready()){
1113                 sm_key_t csrk;
1114                 le_device_db_local_csrk_get(gatt_client->le_device_index, csrk);
1115                 uint32_t sign_counter = le_device_db_local_counter_get(gatt_client->le_device_index);
1116                 gatt_client->gatt_client_state = P_W4_CMAC_RESULT;
1117                 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);
1118             }
1119             return 0;
1120 
1121         case P_W2_SEND_SIGNED_WRITE: {
1122             gatt_client->gatt_client_state = P_W4_SEND_SINGED_WRITE_DONE;
1123             // bump local signing counter
1124             uint32_t sign_counter = le_device_db_local_counter_get(gatt_client->le_device_index);
1125             le_device_db_local_counter_set(gatt_client->le_device_index, sign_counter + 1);
1126             // send signed write command
1127             send_gatt_signed_write_request(gatt_client, sign_counter);
1128             // finally, notifiy client that write is complete
1129             gatt_client_handle_transaction_complete(gatt_client);
1130             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1131             return 1;
1132         }
1133 #endif
1134         default:
1135             break;
1136     }
1137 
1138     // requested can send snow?
1139     if (gatt_client->write_without_response_callback){
1140         btstack_packet_handler_t packet_handler = gatt_client->write_without_response_callback;
1141         gatt_client->write_without_response_callback = NULL;
1142         uint8_t event[4];
1143         event[0] = GATT_EVENT_CAN_WRITE_WITHOUT_RESPONSE;
1144         event[1] = sizeof(event) - 2u;
1145         little_endian_store_16(event, 2, gatt_client->con_handle);
1146         packet_handler(HCI_EVENT_PACKET, gatt_client->con_handle, event, sizeof(event));
1147         return 1; // to trigger requeueing (even if higher layer didn't sent)
1148     }
1149 
1150     return 0;
1151 }
1152 
1153 static void gatt_client_run(void){
1154     btstack_linked_item_t *it;
1155     for (it = (btstack_linked_item_t *) gatt_client_connections; it != NULL; it = it->next){
1156         gatt_client_t * gatt_client = (gatt_client_t *) it;
1157         if (!att_dispatch_client_can_send_now(gatt_client->con_handle)) {
1158             att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
1159             return;
1160         }
1161         int packet_sent = gatt_client_run_for_gatt_client(gatt_client);
1162         if (packet_sent){
1163             // request new permission
1164             att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
1165             // requeue client for fairness and exit
1166             // note: iterator has become invalid
1167             btstack_linked_list_remove(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1168             btstack_linked_list_add_tail(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1169             return;
1170         }
1171     }
1172 }
1173 
1174 static void gatt_client_report_error_if_pending(gatt_client_t *gatt_client, uint8_t att_error_code) {
1175     if (is_ready(gatt_client) == 1) return;
1176     gatt_client_handle_transaction_complete(gatt_client);
1177     emit_gatt_complete_event(gatt_client, att_error_code);
1178 }
1179 
1180 static void gatt_client_event_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1181     UNUSED(channel);    // ok: handling own l2cap events
1182     UNUSED(size);       // ok: there is no channel
1183 
1184     if (packet_type != HCI_EVENT_PACKET) return;
1185 
1186     hci_con_handle_t con_handle;
1187     gatt_client_t * gatt_client;
1188     switch (hci_event_packet_get_type(packet)) {
1189         case HCI_EVENT_DISCONNECTION_COMPLETE:
1190             log_info("GATT Client: HCI_EVENT_DISCONNECTION_COMPLETE");
1191             con_handle = little_endian_read_16(packet,3);
1192             gatt_client = gatt_client_get_context_for_handle(con_handle);
1193             if (gatt_client == NULL) break;
1194 
1195             gatt_client_report_error_if_pending(gatt_client, ATT_ERROR_HCI_DISCONNECT_RECEIVED);
1196             gatt_client_timeout_stop(gatt_client);
1197             btstack_linked_list_remove(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1198             btstack_memory_gatt_client_free(gatt_client);
1199             break;
1200 
1201         // Pairing complete (with/without bonding=storing of pairing information)
1202         case SM_EVENT_PAIRING_COMPLETE:
1203             con_handle = sm_event_pairing_complete_get_handle(packet);
1204             gatt_client = gatt_client_get_context_for_handle(con_handle);
1205             if (gatt_client == NULL) break;
1206 
1207             // update security level
1208             gatt_client->security_level = gatt_client_le_security_level_for_connection(con_handle);
1209 
1210             if (gatt_client->wait_for_pairing_complete){
1211                 gatt_client->wait_for_pairing_complete = 0;
1212                 if (sm_event_pairing_complete_get_status(packet)){
1213                     log_info("pairing failed, report previous error 0x%x", gatt_client->pending_error_code);
1214                     gatt_client_report_error_if_pending(gatt_client, gatt_client->pending_error_code);
1215                 } else {
1216                     log_info("pairing success, retry operation");
1217                 }
1218             }
1219             break;
1220 
1221 #ifdef ENABLE_LE_SIGNED_WRITE
1222         // Identity Resolving completed (no code, gatt_client_run will continue)
1223         case SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED:
1224         case SM_EVENT_IDENTITY_RESOLVING_FAILED:
1225             break;
1226 #endif
1227 
1228         // re-encryption started
1229         case SM_EVENT_REENCRYPTION_STARTED:
1230             con_handle = sm_event_reencryption_complete_get_handle(packet);
1231             gatt_client = gatt_client_get_context_for_handle(con_handle);
1232             if (gatt_client == NULL) break;
1233 
1234             gatt_client->reencryption_active = true;
1235             gatt_client->reencryption_result = ERROR_CODE_SUCCESS;
1236             break;
1237 
1238         // re-encryption complete
1239         case SM_EVENT_REENCRYPTION_COMPLETE:
1240             con_handle = sm_event_reencryption_complete_get_handle(packet);
1241             gatt_client = gatt_client_get_context_for_handle(con_handle);
1242             if (gatt_client == NULL) break;
1243 
1244             // update security level
1245             gatt_client->security_level = gatt_client_le_security_level_for_connection(con_handle);
1246 
1247             gatt_client->reencryption_result = sm_event_reencryption_complete_get_status(packet);
1248             gatt_client->reencryption_active = false;
1249             break;
1250         default:
1251             break;
1252     }
1253 
1254     gatt_client_run();
1255 }
1256 
1257 static void gatt_client_att_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
1258     gatt_client_t * gatt_client;
1259     if (size < 1u) return;
1260 
1261     if (packet_type == HCI_EVENT_PACKET) {
1262         switch (packet[0]){
1263             case L2CAP_EVENT_CAN_SEND_NOW:
1264                 gatt_client_run();
1265                 break;
1266             // att_server has negotiated the mtu for this connection, cache if context exists
1267             case ATT_EVENT_MTU_EXCHANGE_COMPLETE:
1268                 if (size < 6u) break;
1269                 gatt_client = gatt_client_get_context_for_handle(handle);
1270                 if (gatt_client == NULL) break;
1271                 gatt_client->mtu = little_endian_read_16(packet, 4);
1272                 break;
1273             default:
1274                 break;
1275         }
1276         return;
1277     }
1278 
1279     if (packet_type != ATT_DATA_PACKET) return;
1280 
1281     // special cases: notifications don't need a context while indications motivate creating one
1282     switch (packet[0]){
1283         case ATT_HANDLE_VALUE_NOTIFICATION:
1284             if (size < 3u) return;
1285             report_gatt_notification(handle, little_endian_read_16(packet,1u), &packet[3], size-3u);
1286             return;
1287         case ATT_HANDLE_VALUE_INDICATION:
1288             gatt_client = gatt_client_provide_context_for_handle(handle);
1289             break;
1290         default:
1291             gatt_client = gatt_client_get_context_for_handle(handle);
1292             break;
1293     }
1294 
1295     if (gatt_client == NULL) return;
1296 
1297     uint8_t error_code;
1298     switch (packet[0]){
1299         case ATT_EXCHANGE_MTU_RESPONSE:
1300         {
1301             if (size < 3u) break;
1302             uint16_t remote_rx_mtu = little_endian_read_16(packet, 1);
1303             uint16_t local_rx_mtu = l2cap_max_le_mtu();
1304             gatt_client->mtu = (remote_rx_mtu < local_rx_mtu) ? remote_rx_mtu : local_rx_mtu;
1305             gatt_client->mtu_state = MTU_EXCHANGED;
1306             emit_gatt_mtu_exchanged_result_event(gatt_client, gatt_client->mtu);
1307             break;
1308         }
1309         case ATT_READ_BY_GROUP_TYPE_RESPONSE:
1310             switch(gatt_client->gatt_client_state){
1311                 case P_W4_SERVICE_QUERY_RESULT:
1312                     report_gatt_services(gatt_client, packet, size);
1313                     trigger_next_service_query(gatt_client, get_last_result_handle_from_service_list(packet, size));
1314                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1315                     break;
1316                 default:
1317                     break;
1318             }
1319             break;
1320         case ATT_HANDLE_VALUE_INDICATION:
1321             if (size < 3u) break;
1322             report_gatt_indication(handle, little_endian_read_16(packet,1u), &packet[3], size-3u);
1323             gatt_client->send_confirmation = 1;
1324             break;
1325 
1326         case ATT_READ_BY_TYPE_RESPONSE:
1327             switch (gatt_client->gatt_client_state){
1328                 case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1329                     report_gatt_characteristics(gatt_client, packet, size);
1330                     trigger_next_characteristic_query(gatt_client, get_last_result_handle_from_characteristics_list(packet, size));
1331                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1332                     break;
1333                 case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1334                     report_gatt_characteristics(gatt_client, packet, size);
1335                     trigger_next_characteristic_query(gatt_client, get_last_result_handle_from_characteristics_list(packet, size));
1336                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1337                     break;
1338                 case P_W4_INCLUDED_SERVICE_QUERY_RESULT:
1339                 {
1340                     if (size < 2u) break;
1341                     uint16_t uuid16 = 0;
1342                     uint16_t pair_size = packet[1];
1343 
1344                     if (pair_size == 6u){
1345                         if (size < 8u) break;
1346                         // UUIDs not available, query first included service
1347                         gatt_client->start_group_handle = little_endian_read_16(packet, 2); // ready for next query
1348                         gatt_client->query_start_handle = little_endian_read_16(packet, 4);
1349                         gatt_client->query_end_handle = little_endian_read_16(packet, 6);
1350                         gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY;
1351                         break;
1352                     }
1353 
1354                     if (pair_size != 8u) break;
1355 
1356                     // UUIDs included, report all of them
1357                     uint16_t offset;
1358                     for (offset = 2u; (offset + 8u) <= size; offset += pair_size){
1359                         uint16_t include_handle = little_endian_read_16(packet, offset);
1360                         gatt_client->query_start_handle = little_endian_read_16(packet, offset + 2u);
1361                         gatt_client->query_end_handle = little_endian_read_16(packet, offset + 4u);
1362                         uuid16 = little_endian_read_16(packet, offset+6u);
1363                         report_gatt_included_service_uuid16(gatt_client, include_handle, uuid16);
1364                     }
1365 
1366                     trigger_next_included_service_query(gatt_client, get_last_result_handle_from_included_services_list(packet, size));
1367                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1368                     break;
1369                 }
1370 #ifndef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1371                 case P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT:
1372                     gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, 2);
1373                     gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1374                     break;
1375 #endif
1376                 case P_W4_READ_BY_TYPE_RESPONSE: {
1377                     uint16_t pair_size = packet[1];
1378                     uint16_t offset;
1379                     uint16_t last_result_handle = 0;
1380                     for (offset = 2; offset < size ; offset += pair_size){
1381                         uint16_t value_handle = little_endian_read_16(packet, offset);
1382                         report_gatt_characteristic_value(gatt_client, value_handle, &packet[offset + 2u], pair_size - 2u);
1383                         last_result_handle = value_handle;
1384                     }
1385                     trigger_next_read_by_type_query(gatt_client, last_result_handle);
1386                     break;
1387                 }
1388                 default:
1389                     break;
1390             }
1391             break;
1392         case ATT_READ_RESPONSE:
1393             switch (gatt_client->gatt_client_state){
1394                 case P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT: {
1395                     uint8_t uuid128[16];
1396                     reverse_128(&packet[1], uuid128);
1397                     report_gatt_included_service_uuid128(gatt_client, gatt_client->start_group_handle, uuid128);
1398                     trigger_next_included_service_query(gatt_client, gatt_client->start_group_handle);
1399                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1400                     break;
1401                 }
1402                 case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1403                     gatt_client_handle_transaction_complete(gatt_client);
1404                     report_gatt_characteristic_value(gatt_client, gatt_client->attribute_handle, &packet[1], size - 1u);
1405                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1406                     break;
1407 
1408                 case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:{
1409                     gatt_client_handle_transaction_complete(gatt_client);
1410                     report_gatt_characteristic_descriptor(gatt_client, gatt_client->attribute_handle, &packet[1], size - 1u, 0u);
1411                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1412                     break;
1413                 }
1414                 default:
1415                     break;
1416             }
1417             break;
1418 
1419         case ATT_FIND_BY_TYPE_VALUE_RESPONSE:
1420         {
1421             uint8_t pair_size = 4;
1422             int i;
1423             uint16_t start_group_handle;
1424             uint16_t   end_group_handle= 0xffff; // asserts GATT_EVENT_QUERY_COMPLETE is emitted if no results
1425             for (i = 1u; (i + pair_size) <= size; i += pair_size){
1426                 start_group_handle = little_endian_read_16(packet,i);
1427                 end_group_handle = little_endian_read_16(packet,i+2);
1428                 emit_gatt_service_query_result_event(gatt_client, start_group_handle, end_group_handle, gatt_client->uuid128);
1429             }
1430             trigger_next_service_by_uuid_query(gatt_client, end_group_handle);
1431             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1432             break;
1433         }
1434         case ATT_FIND_INFORMATION_REPLY:
1435         {
1436             if (size < 2u) break;
1437 
1438             uint8_t pair_size = 4;
1439             if (packet[1u] == 2u){
1440                 pair_size = 18;
1441             }
1442             uint16_t offset = 2;
1443 
1444             if (size < (pair_size + offset)) break;
1445             uint16_t last_descriptor_handle = little_endian_read_16(packet, size - pair_size);
1446 
1447 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1448             log_info("ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY, state %x", gatt_client->gatt_client_state);
1449             if (gatt_client->gatt_client_state == P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT){
1450                 // iterate over descriptors looking for CCC
1451                 if (pair_size == 4){
1452                     while ((offset + 4) <= size){
1453                         uint16_t uuid16 = little_endian_read_16(packet, offset + 2);
1454                         if (uuid16 == GATT_CLIENT_CHARACTERISTICS_CONFIGURATION){
1455                             gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, offset);
1456                             gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1457                             log_info("CCC found %x", gatt_client->client_characteristic_configuration_handle);
1458                             break;
1459                         }
1460                         offset += pair_size;
1461                     }
1462                 }
1463                 if (is_query_done(gatt_client, last_descriptor_handle)){
1464 
1465                 } else {
1466                     // next
1467                     gatt_client->start_group_handle = last_descriptor_handle + 1;
1468                     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
1469                 }
1470                 break;
1471             }
1472 #endif
1473             report_gatt_all_characteristic_descriptors(gatt_client, &packet[2], size - 2u, pair_size);
1474             trigger_next_characteristic_descriptor_query(gatt_client, last_descriptor_handle);
1475             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1476             break;
1477         }
1478 
1479         case ATT_WRITE_RESPONSE:
1480             switch (gatt_client->gatt_client_state){
1481                 case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1482                     gatt_client_handle_transaction_complete(gatt_client);
1483                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1484                     break;
1485                 case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1486                     gatt_client_handle_transaction_complete(gatt_client);
1487                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1488                     break;
1489                 case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1490                     gatt_client_handle_transaction_complete(gatt_client);
1491                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1492                     break;
1493                 default:
1494                     break;
1495             }
1496             break;
1497 
1498         case ATT_READ_BLOB_RESPONSE:{
1499             uint16_t received_blob_length = size-1u;
1500             switch(gatt_client->gatt_client_state){
1501                 case P_W4_READ_BLOB_RESULT:
1502                     report_gatt_long_characteristic_value_blob(gatt_client, gatt_client->attribute_handle, &packet[1], received_blob_length, gatt_client->attribute_offset);
1503                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_QUERY, received_blob_length);
1504                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1505                     break;
1506                 case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1507                     report_gatt_long_characteristic_descriptor(gatt_client, gatt_client->attribute_handle,
1508                                                                &packet[1], received_blob_length,
1509                                                                gatt_client->attribute_offset);
1510                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY, received_blob_length);
1511                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1512                     break;
1513                 default:
1514                     break;
1515             }
1516             break;
1517         }
1518         case ATT_PREPARE_WRITE_RESPONSE:
1519             switch (gatt_client->gatt_client_state){
1520                 case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1521                     gatt_client_handle_transaction_complete(gatt_client);
1522                     if (is_value_valid(gatt_client, packet, size)){
1523                         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1524                     } else {
1525                         emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1526                     }
1527                     break;
1528 
1529                 case P_W4_PREPARE_WRITE_RESULT:{
1530                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1531                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE, P_W2_EXECUTE_PREPARED_WRITE);
1532                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1533                     break;
1534                 }
1535                 case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:{
1536                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1537                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR, P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR);
1538                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1539                     break;
1540                 }
1541                 case P_W4_PREPARE_RELIABLE_WRITE_RESULT:{
1542                     if (is_value_valid(gatt_client, packet, size)){
1543                         gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1544                         trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_RELIABLE_WRITE, P_W2_EXECUTE_PREPARED_WRITE);
1545                         // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1546                         break;
1547                     }
1548                     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1549                     break;
1550                 }
1551                 default:
1552                     break;
1553             }
1554             break;
1555 
1556         case ATT_EXECUTE_WRITE_RESPONSE:
1557             switch (gatt_client->gatt_client_state){
1558                 case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1559                     gatt_client_handle_transaction_complete(gatt_client);
1560                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1561                     break;
1562                 case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1563                     gatt_client_handle_transaction_complete(gatt_client);
1564                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1565                     break;
1566                 case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1567                     gatt_client_handle_transaction_complete(gatt_client);
1568                     emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1569                     break;
1570                 case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1571                     gatt_client_handle_transaction_complete(gatt_client);
1572                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1573                     break;
1574                 default:
1575                     break;
1576 
1577             }
1578             break;
1579 
1580         case ATT_READ_MULTIPLE_RESPONSE:
1581             switch(gatt_client->gatt_client_state){
1582                 case P_W4_READ_MULTIPLE_RESPONSE:
1583                     report_gatt_characteristic_value(gatt_client, 0u, &packet[1], size - 1u);
1584                     gatt_client_handle_transaction_complete(gatt_client);
1585                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1586                     break;
1587                 default:
1588                     break;
1589             }
1590             break;
1591 
1592         case ATT_ERROR_RESPONSE:
1593             if (size < 5u) return;
1594             error_code = packet[4];
1595             switch (error_code){
1596                 case ATT_ERROR_ATTRIBUTE_NOT_FOUND: {
1597                     switch(gatt_client->gatt_client_state){
1598                         case P_W4_SERVICE_QUERY_RESULT:
1599                         case P_W4_SERVICE_WITH_UUID_RESULT:
1600                         case P_W4_INCLUDED_SERVICE_QUERY_RESULT:
1601                         case P_W4_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT:
1602                             gatt_client_handle_transaction_complete(gatt_client);
1603                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1604                             break;
1605                         case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1606                         case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1607                             characteristic_end_found(gatt_client, gatt_client->end_group_handle);
1608                             gatt_client_handle_transaction_complete(gatt_client);
1609                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1610                             break;
1611                         case P_W4_READ_BY_TYPE_RESPONSE:
1612                             gatt_client_handle_transaction_complete(gatt_client);
1613                             if (gatt_client->start_group_handle == gatt_client->query_start_handle){
1614                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_ATTRIBUTE_NOT_FOUND);
1615                             } else {
1616                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1617                             }
1618                             break;
1619                         default:
1620                             gatt_client_report_error_if_pending(gatt_client, error_code);
1621                             break;
1622                     }
1623                     break;
1624                 }
1625 
1626 #ifdef ENABLE_GATT_CLIENT_PAIRING
1627 
1628                 case ATT_ERROR_INSUFFICIENT_AUTHENTICATION:
1629                 case ATT_ERROR_INSUFFICIENT_ENCRYPTION_KEY_SIZE:
1630                 case ATT_ERROR_INSUFFICIENT_ENCRYPTION: {
1631 
1632                     // security too low
1633                     if (gatt_client->security_counter > 0) {
1634                         gatt_client_report_error_if_pending(gatt_client, error_code);
1635                         break;
1636                     }
1637                     // start security
1638                     gatt_client->security_counter++;
1639 
1640                     // setup action
1641                     int retry = 1;
1642                     switch (gatt_client->gatt_client_state){
1643                         case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1644                             gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY ;
1645                             break;
1646                         case P_W4_READ_BLOB_RESULT:
1647                             gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
1648                             break;
1649                         case P_W4_READ_BY_TYPE_RESPONSE:
1650                             gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1651                             break;
1652                         case P_W4_READ_MULTIPLE_RESPONSE:
1653                             gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
1654                             break;
1655                         case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1656                             gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
1657                             break;
1658                         case P_W4_PREPARE_WRITE_RESULT:
1659                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
1660                             break;
1661                         case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1662                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
1663                             break;
1664                         case P_W4_PREPARE_RELIABLE_WRITE_RESULT:
1665                             gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
1666                             break;
1667                         case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1668                             gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
1669                             break;
1670                         case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1671                             gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
1672                             break;
1673                         case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1674                             gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1675                             break;
1676                         case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:
1677                             gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
1678                             break;
1679                         case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1680                             gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
1681                             break;
1682                         case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1683                             gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
1684                             break;
1685                         case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1686                             gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1687                             break;
1688                         case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1689                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
1690                             break;
1691                         case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1692                             gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR;
1693                             break;
1694 #ifdef ENABLE_LE_SIGNED_WRITE
1695                         case P_W4_SEND_SINGED_WRITE_DONE:
1696                             gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1697                             break;
1698 #endif
1699                         default:
1700                             log_info("retry not supported for state %x", gatt_client->gatt_client_state);
1701                             retry = 0;
1702                             break;
1703                     }
1704 
1705                     if (!retry) {
1706                         gatt_client_report_error_if_pending(gatt_client, error_code);
1707                         break;
1708                     }
1709 
1710                     log_info("security error, start pairing");
1711 
1712                     // start pairing for higher security level
1713                     gatt_client->wait_for_pairing_complete = 1;
1714                     gatt_client->pending_error_code = error_code;
1715                     sm_request_pairing(gatt_client->con_handle);
1716                     break;
1717                 }
1718 #endif
1719 
1720                 // nothing we can do about that
1721                 case ATT_ERROR_INSUFFICIENT_AUTHORIZATION:
1722                 default:
1723                     gatt_client_report_error_if_pending(gatt_client, error_code);
1724                     break;
1725             }
1726             break;
1727 
1728         default:
1729             log_info("ATT Handler, unhandled response type 0x%02x", packet[0]);
1730             break;
1731     }
1732     gatt_client_run();
1733 }
1734 
1735 #ifdef ENABLE_LE_SIGNED_WRITE
1736 static void att_signed_write_handle_cmac_result(uint8_t hash[8]){
1737     btstack_linked_list_iterator_t it;
1738     btstack_linked_list_iterator_init(&it, &gatt_client_connections);
1739     while (btstack_linked_list_iterator_has_next(&it)){
1740         gatt_client_t * gatt_client = (gatt_client_t *) btstack_linked_list_iterator_next(&it);
1741         if (gatt_client->gatt_client_state == P_W4_CMAC_RESULT){
1742             // store result
1743             (void)memcpy(gatt_client->cmac, hash, 8);
1744             // reverse_64(hash, gatt_client->cmac);
1745             gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1746             gatt_client_run();
1747             return;
1748         }
1749     }
1750 }
1751 
1752 uint8_t gatt_client_signed_write_without_response(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t handle, uint16_t message_len, uint8_t * message){
1753     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
1754     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1755     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1756 
1757     gatt_client->callback = callback;
1758     gatt_client->attribute_handle = handle;
1759     gatt_client->attribute_length = message_len;
1760     gatt_client->attribute_value = message;
1761     gatt_client->gatt_client_state = P_W4_IDENTITY_RESOLVING;
1762     gatt_client_run();
1763     return ERROR_CODE_SUCCESS;
1764 }
1765 #endif
1766 
1767 uint8_t gatt_client_discover_primary_services(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
1768     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1769     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1770     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1771 
1772     gatt_client->callback = callback;
1773     gatt_client->start_group_handle = 0x0001;
1774     gatt_client->end_group_handle   = 0xffff;
1775     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_QUERY;
1776     gatt_client->uuid16 = 0;
1777     gatt_client_run();
1778     return ERROR_CODE_SUCCESS;
1779 }
1780 
1781 
1782 uint8_t gatt_client_discover_primary_services_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t uuid16){
1783     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1784     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1785     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1786 
1787     gatt_client->callback = callback;
1788     gatt_client->start_group_handle = 0x0001;
1789     gatt_client->end_group_handle   = 0xffff;
1790     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
1791     gatt_client->uuid16 = uuid16;
1792     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), gatt_client->uuid16);
1793     gatt_client_run();
1794     return ERROR_CODE_SUCCESS;
1795 }
1796 
1797 uint8_t gatt_client_discover_primary_services_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, const uint8_t * uuid128){
1798     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1799     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1800     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1801 
1802     gatt_client->callback = callback;
1803     gatt_client->start_group_handle = 0x0001;
1804     gatt_client->end_group_handle   = 0xffff;
1805     gatt_client->uuid16 = 0;
1806     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1807     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
1808     gatt_client_run();
1809     return ERROR_CODE_SUCCESS;
1810 }
1811 
1812 uint8_t gatt_client_discover_characteristics_for_service(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t *service){
1813     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1814     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1815     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1816 
1817     gatt_client->callback = callback;
1818     gatt_client->start_group_handle = service->start_group_handle;
1819     gatt_client->end_group_handle   = service->end_group_handle;
1820     gatt_client->filter_with_uuid = 0;
1821     gatt_client->characteristic_start_handle = 0;
1822     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY;
1823     gatt_client_run();
1824     return ERROR_CODE_SUCCESS;
1825 }
1826 
1827 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){
1828     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1829     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1830     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1831     gatt_client->callback = callback;
1832     gatt_client->start_group_handle = service->start_group_handle;
1833     gatt_client->end_group_handle   = service->end_group_handle;
1834     gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_QUERY;
1835 
1836     gatt_client_run();
1837     return ERROR_CODE_SUCCESS;
1838 }
1839 
1840 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){
1841     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1842     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1843     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1844 
1845     gatt_client->callback = callback;
1846     gatt_client->start_group_handle = start_handle;
1847     gatt_client->end_group_handle   = end_handle;
1848     gatt_client->filter_with_uuid = 1;
1849     gatt_client->uuid16 = uuid16;
1850     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
1851     gatt_client->characteristic_start_handle = 0;
1852     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
1853     gatt_client_run();
1854     return ERROR_CODE_SUCCESS;
1855 }
1856 
1857 uint8_t gatt_client_discover_characteristics_for_handle_range_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t start_handle, uint16_t end_handle, uint8_t * uuid128){
1858     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1859     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1860     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1861 
1862     gatt_client->callback = callback;
1863     gatt_client->start_group_handle = start_handle;
1864     gatt_client->end_group_handle   = end_handle;
1865     gatt_client->filter_with_uuid = 1;
1866     gatt_client->uuid16 = 0;
1867     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1868     gatt_client->characteristic_start_handle = 0;
1869     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
1870     gatt_client_run();
1871     return ERROR_CODE_SUCCESS;
1872 }
1873 
1874 
1875 uint8_t gatt_client_discover_characteristics_for_service_by_uuid16(btstack_packet_handler_t callback, uint16_t handle, gatt_client_service_t *service, uint16_t  uuid16){
1876     return gatt_client_discover_characteristics_for_handle_range_by_uuid16(callback, handle, service->start_group_handle, service->end_group_handle, uuid16);
1877 }
1878 
1879 uint8_t gatt_client_discover_characteristics_for_service_by_uuid128(btstack_packet_handler_t callback, uint16_t handle, gatt_client_service_t *service, uint8_t * uuid128){
1880     return gatt_client_discover_characteristics_for_handle_range_by_uuid128(callback, handle, service->start_group_handle, service->end_group_handle, uuid128);
1881 }
1882 
1883 uint8_t gatt_client_discover_characteristic_descriptors(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t *characteristic){
1884     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1885     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1886     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1887 
1888     if (characteristic->value_handle == characteristic->end_handle){
1889         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1890         return ERROR_CODE_SUCCESS;
1891     }
1892     gatt_client->callback = callback;
1893     gatt_client->start_group_handle = characteristic->value_handle + 1u;
1894     gatt_client->end_group_handle   = characteristic->end_handle;
1895     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY;
1896     gatt_client_run();
1897     return ERROR_CODE_SUCCESS;
1898 }
1899 
1900 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){
1901     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1902     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1903     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1904 
1905     gatt_client->callback = callback;
1906     gatt_client->attribute_handle = value_handle;
1907     gatt_client->attribute_offset = 0;
1908     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY;
1909     gatt_client_run();
1910     return ERROR_CODE_SUCCESS;
1911 }
1912 
1913 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){
1914     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1915     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1916     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1917 
1918     gatt_client->callback = callback;
1919     gatt_client->start_group_handle = start_handle;
1920     gatt_client->end_group_handle = end_handle;
1921     gatt_client->query_start_handle = start_handle;
1922     gatt_client->query_end_handle = end_handle;
1923     gatt_client->uuid16 = uuid16;
1924     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
1925     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1926     gatt_client_run();
1927     return ERROR_CODE_SUCCESS;
1928 }
1929 
1930 uint8_t gatt_client_read_value_of_characteristics_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t start_handle, uint16_t end_handle, uint8_t * uuid128){
1931     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1932     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1933     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1934 
1935     gatt_client->callback = callback;
1936     gatt_client->start_group_handle = start_handle;
1937     gatt_client->end_group_handle = end_handle;
1938     gatt_client->query_start_handle = start_handle;
1939     gatt_client->query_end_handle = end_handle;
1940     gatt_client->uuid16 = 0;
1941     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1942     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1943     gatt_client_run();
1944     return ERROR_CODE_SUCCESS;
1945 }
1946 
1947 
1948 uint8_t gatt_client_read_value_of_characteristic(btstack_packet_handler_t callback, uint16_t handle, gatt_client_characteristic_t *characteristic){
1949     return gatt_client_read_value_of_characteristic_using_value_handle(callback, handle, characteristic->value_handle);
1950 }
1951 
1952 uint8_t gatt_client_read_long_value_of_characteristic_using_value_handle_with_offset(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t characteristic_value_handle, uint16_t offset){
1953     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1954     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1955     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1956 
1957     gatt_client->callback = callback;
1958     gatt_client->attribute_handle = characteristic_value_handle;
1959     gatt_client->attribute_offset = offset;
1960     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
1961     gatt_client_run();
1962     return ERROR_CODE_SUCCESS;
1963 }
1964 
1965 uint8_t gatt_client_read_long_value_of_characteristic_using_value_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t characteristic_value_handle){
1966     return gatt_client_read_long_value_of_characteristic_using_value_handle_with_offset(callback, con_handle, characteristic_value_handle, 0);
1967 }
1968 
1969 uint8_t gatt_client_read_long_value_of_characteristic(btstack_packet_handler_t callback, uint16_t handle, gatt_client_characteristic_t *characteristic){
1970     return gatt_client_read_long_value_of_characteristic_using_value_handle(callback, handle, characteristic->value_handle);
1971 }
1972 
1973 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){
1974     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1975     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1976     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1977 
1978     gatt_client->callback = callback;
1979     gatt_client->read_multiple_handle_count = num_value_handles;
1980     gatt_client->read_multiple_handles = value_handles;
1981     gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
1982     gatt_client_run();
1983     return ERROR_CODE_SUCCESS;
1984 }
1985 
1986 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){
1987     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
1988     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1989 
1990     if (value_length > (gatt_client->mtu - 3u)) return GATT_CLIENT_VALUE_TOO_LONG;
1991     if (!att_dispatch_client_can_send_now(gatt_client->con_handle)) return GATT_CLIENT_BUSY;
1992 
1993     return att_write_request(ATT_WRITE_COMMAND, gatt_client->con_handle, value_handle, value_length, value);
1994 }
1995 
1996 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 * data){
1997     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1998     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1999     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2000 
2001     gatt_client->callback = callback;
2002     gatt_client->attribute_handle = value_handle;
2003     gatt_client->attribute_length = value_length;
2004     gatt_client->attribute_value = data;
2005     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
2006     gatt_client_run();
2007     return ERROR_CODE_SUCCESS;
2008 }
2009 
2010 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  * data){
2011     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2012     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2013     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2014 
2015     gatt_client->callback = callback;
2016     gatt_client->attribute_handle = value_handle;
2017     gatt_client->attribute_length = value_length;
2018     gatt_client->attribute_offset = offset;
2019     gatt_client->attribute_value = data;
2020     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
2021     gatt_client_run();
2022     return ERROR_CODE_SUCCESS;
2023 }
2024 
2025 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){
2026     return gatt_client_write_long_value_of_characteristic_with_offset(callback, con_handle, value_handle, 0, value_length, value);
2027 }
2028 
2029 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){
2030     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2031     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2032     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2033 
2034     gatt_client->callback = callback;
2035     gatt_client->attribute_handle = value_handle;
2036     gatt_client->attribute_length = value_length;
2037     gatt_client->attribute_offset = 0;
2038     gatt_client->attribute_value = value;
2039     gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
2040     gatt_client_run();
2041     return ERROR_CODE_SUCCESS;
2042 }
2043 
2044 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){
2045     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2046     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2047     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2048 
2049     if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION) &&
2050         ((characteristic->properties & ATT_PROPERTY_NOTIFY) == 0u)) {
2051         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED");
2052         return GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED;
2053     } else if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_INDICATION) &&
2054                ((characteristic->properties & ATT_PROPERTY_INDICATE) == 0u)){
2055         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED");
2056         return GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED;
2057     }
2058 
2059     gatt_client->callback = callback;
2060     gatt_client->start_group_handle = characteristic->value_handle;
2061     gatt_client->end_group_handle = characteristic->end_handle;
2062     little_endian_store_16(gatt_client->client_characteristic_configuration_value, 0, configuration);
2063 
2064 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
2065     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
2066 #else
2067     gatt_client->gatt_client_state = P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
2068 #endif
2069     gatt_client_run();
2070     return ERROR_CODE_SUCCESS;
2071 }
2072 
2073 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){
2074     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2075     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2076     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2077 
2078     gatt_client->callback = callback;
2079     gatt_client->attribute_handle = descriptor_handle;
2080 
2081     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
2082     gatt_client_run();
2083     return ERROR_CODE_SUCCESS;
2084 }
2085 
2086 uint8_t gatt_client_read_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t * descriptor){
2087     return gatt_client_read_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
2088 }
2089 
2090 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){
2091     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2092     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2093     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2094 
2095     gatt_client->callback = callback;
2096     gatt_client->attribute_handle = descriptor_handle;
2097     gatt_client->attribute_offset = offset;
2098     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
2099     gatt_client_run();
2100     return ERROR_CODE_SUCCESS;
2101 }
2102 
2103 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){
2104     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0);
2105 }
2106 
2107 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){
2108     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
2109 }
2110 
2111 uint8_t gatt_client_write_characteristic_descriptor_using_descriptor_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t descriptor_handle, uint16_t length, uint8_t  * data){
2112     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2113     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2114     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2115 
2116     gatt_client->callback = callback;
2117     gatt_client->attribute_handle = descriptor_handle;
2118     gatt_client->attribute_length = length;
2119     gatt_client->attribute_offset = 0;
2120     gatt_client->attribute_value = data;
2121     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
2122     gatt_client_run();
2123     return ERROR_CODE_SUCCESS;
2124 }
2125 
2126 uint8_t gatt_client_write_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t * descriptor, uint16_t length, uint8_t * value){
2127     return gatt_client_write_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, length, value);
2128 }
2129 
2130 uint8_t gatt_client_write_long_characteristic_descriptor_using_descriptor_handle_with_offset(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t descriptor_handle, uint16_t offset, uint16_t length, uint8_t  * data){
2131     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2132     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2133     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2134 
2135     gatt_client->callback = callback;
2136     gatt_client->attribute_handle = descriptor_handle;
2137     gatt_client->attribute_length = length;
2138     gatt_client->attribute_offset = offset;
2139     gatt_client->attribute_value = data;
2140     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
2141     gatt_client_run();
2142     return ERROR_CODE_SUCCESS;
2143 }
2144 
2145 uint8_t gatt_client_write_long_characteristic_descriptor_using_descriptor_handle(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t descriptor_handle, uint16_t length, uint8_t * data){
2146     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0, length, data );
2147 }
2148 
2149 uint8_t gatt_client_write_long_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t * descriptor, uint16_t length, uint8_t * value){
2150     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, length, value);
2151 }
2152 
2153 /**
2154  * @brief -> gatt complete event
2155  */
2156 uint8_t gatt_client_prepare_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t attribute_handle, uint16_t offset, uint16_t length, uint8_t * data){
2157     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2158     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2159     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2160 
2161     gatt_client->callback = callback;
2162     gatt_client->attribute_handle = attribute_handle;
2163     gatt_client->attribute_length = length;
2164     gatt_client->attribute_offset = offset;
2165     gatt_client->attribute_value = data;
2166     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
2167     gatt_client_run();
2168     return ERROR_CODE_SUCCESS;
2169 }
2170 
2171 /**
2172  * @brief -> gatt complete event
2173  */
2174 uint8_t gatt_client_execute_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2175     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2176 
2177     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2178     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2179 
2180     gatt_client->callback = callback;
2181     gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
2182     gatt_client_run();
2183     return ERROR_CODE_SUCCESS;
2184 }
2185 
2186 /**
2187  * @brief -> gatt complete event
2188  */
2189 uint8_t gatt_client_cancel_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2190     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2191     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2192     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2193 
2194     gatt_client->callback = callback;
2195     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
2196     gatt_client_run();
2197     return ERROR_CODE_SUCCESS;
2198 }
2199 
2200 void gatt_client_deserialize_service(const uint8_t *packet, int offset, gatt_client_service_t *service){
2201     service->start_group_handle = little_endian_read_16(packet, offset);
2202     service->end_group_handle = little_endian_read_16(packet, offset + 2);
2203     reverse_128(&packet[offset + 4], service->uuid128);
2204     if (uuid_has_bluetooth_prefix(service->uuid128)){
2205         service->uuid16 = big_endian_read_32(service->uuid128, 0);
2206     } else {
2207         service->uuid16 = 0;
2208     }
2209 }
2210 
2211 void gatt_client_deserialize_characteristic(const uint8_t * packet, int offset, gatt_client_characteristic_t * characteristic){
2212     characteristic->start_handle = little_endian_read_16(packet, offset);
2213     characteristic->value_handle = little_endian_read_16(packet, offset + 2);
2214     characteristic->end_handle = little_endian_read_16(packet, offset + 4);
2215     characteristic->properties = little_endian_read_16(packet, offset + 6);
2216     reverse_128(&packet[offset+8], characteristic->uuid128);
2217     if (uuid_has_bluetooth_prefix(characteristic->uuid128)){
2218         characteristic->uuid16 = big_endian_read_32(characteristic->uuid128, 0);
2219     } else {
2220         characteristic->uuid16 = 0;
2221     }
2222 }
2223 
2224 void gatt_client_deserialize_characteristic_descriptor(const uint8_t * packet, int offset, gatt_client_characteristic_descriptor_t * descriptor){
2225     descriptor->handle = little_endian_read_16(packet, offset);
2226     reverse_128(&packet[offset+2], descriptor->uuid128);
2227     if (uuid_has_bluetooth_prefix(descriptor->uuid128)){
2228         descriptor->uuid16 = big_endian_read_32(descriptor->uuid128, 0);
2229     } else {
2230         descriptor->uuid16 = 0;
2231     }
2232 }
2233 
2234 void gatt_client_send_mtu_negotiation(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2235     gatt_client_t * context = gatt_client_provide_context_for_handle(con_handle);
2236     if (context == NULL) return;
2237     if (context->mtu_state == MTU_AUTO_EXCHANGE_DISABLED){
2238         context->callback = callback;
2239         context->mtu_state = SEND_MTU_EXCHANGE;
2240         gatt_client_run();
2241     }
2242 }
2243 
2244 uint8_t gatt_client_request_can_write_without_response_event(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2245     gatt_client_t * context = gatt_client_provide_context_for_handle(con_handle);
2246     if (context == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2247     if (context->write_without_response_callback != NULL) return GATT_CLIENT_IN_WRONG_STATE;
2248     context->write_without_response_callback = callback;
2249     att_dispatch_client_request_can_send_now_event(context->con_handle);
2250     return ERROR_CODE_SUCCESS;
2251 }
2252 
2253 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
2254 void gatt_client_att_packet_handler_fuzz(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
2255     gatt_client_att_packet_handler(packet_type, handle, packet, size);
2256 }
2257 #endif
2258