xref: /btstack/src/ble/gatt_client.c (revision 79b02f79ab95d5314fe0ff250a2c8d5727813da9)
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 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION
895             hci_remove_le_device_db_entry_from_resolving_list((uint16_t) le_device_db_index);
896 #endif
897             le_device_db_remove(le_device_db_index);
898             // trigger pairing again
899             sm_request_pairing(gatt_client->con_handle);
900             return 0;
901         }
902 #endif
903         // report bonding information missing
904         gatt_client_handle_transaction_complete(gatt_client);
905         emit_gatt_complete_event(gatt_client, ATT_ERROR_BONDING_INFORMATION_MISSING);
906         return 0;
907     }
908 
909     // wait until pairing complete (either reactive authentication or due to required security level)
910     if (gatt_client->wait_for_pairing_complete) return 0;
911 
912     // verify security level
913     if (gatt_client_required_security_level > gatt_client->security_level){
914         log_info("Trigger pairing, current security level %u, required %u\n", gatt_client->security_level, gatt_client_required_security_level);
915         gatt_client->wait_for_pairing_complete = 1;
916         // set att error code for pairing failure based on required level
917         switch (gatt_client_required_security_level){
918             case LEVEL_4:
919             case LEVEL_3:
920                 gatt_client->pending_error_code = ATT_ERROR_INSUFFICIENT_AUTHENTICATION;
921                 break;
922             default:
923                 gatt_client->pending_error_code = ATT_ERROR_INSUFFICIENT_ENCRYPTION;
924                 break;
925         }
926         sm_request_pairing(gatt_client->con_handle);
927         // sm probably just sent a pdu
928         return 1;
929     }
930 
931     switch (gatt_client->mtu_state) {
932         case SEND_MTU_EXCHANGE:
933             gatt_client->mtu_state = SENT_MTU_EXCHANGE;
934             att_exchange_mtu_request(gatt_client->con_handle);
935             return 1;
936         case SENT_MTU_EXCHANGE:
937             return 0;
938         default:
939             break;
940     }
941 
942     if (gatt_client->send_confirmation){
943         gatt_client->send_confirmation = 0;
944         att_confirmation(gatt_client->con_handle);
945         return 1;
946     }
947 
948     // check MTU for writes
949     switch (gatt_client->gatt_client_state){
950         case P_W2_SEND_WRITE_CHARACTERISTIC_VALUE:
951         case P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR:
952             if (gatt_client->attribute_length <= (gatt_client->mtu - 3u)) break;
953             log_error("gatt_client_run: value len %u > MTU %u - 3\n", gatt_client->attribute_length,gatt_client->mtu);
954             gatt_client_handle_transaction_complete(gatt_client);
955             emit_gatt_complete_event(gatt_client, ATT_ERROR_INVALID_ATTRIBUTE_VALUE_LENGTH);
956             return 0;
957         default:
958             break;
959     }
960 
961     switch (gatt_client->gatt_client_state){
962         case P_W2_SEND_SERVICE_QUERY:
963             gatt_client->gatt_client_state = P_W4_SERVICE_QUERY_RESULT;
964             send_gatt_services_request(gatt_client);
965             return 1;
966 
967         case P_W2_SEND_SERVICE_WITH_UUID_QUERY:
968             gatt_client->gatt_client_state = P_W4_SERVICE_WITH_UUID_RESULT;
969             send_gatt_services_by_uuid_request(gatt_client);
970             return 1;
971 
972         case P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY:
973             gatt_client->gatt_client_state = P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT;
974             send_gatt_characteristic_request(gatt_client);
975             return 1;
976 
977         case P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY:
978             gatt_client->gatt_client_state = P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT;
979             send_gatt_characteristic_request(gatt_client);
980             return 1;
981 
982         case P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY:
983             gatt_client->gatt_client_state = P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT;
984             send_gatt_characteristic_descriptor_request(gatt_client);
985             return 1;
986 
987         case P_W2_SEND_INCLUDED_SERVICE_QUERY:
988             gatt_client->gatt_client_state = P_W4_INCLUDED_SERVICE_QUERY_RESULT;
989             send_gatt_included_service_request(gatt_client);
990             return 1;
991 
992         case P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY:
993             gatt_client->gatt_client_state = P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT;
994             send_gatt_included_service_uuid_request(gatt_client);
995             return 1;
996 
997         case P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY:
998             gatt_client->gatt_client_state = P_W4_READ_CHARACTERISTIC_VALUE_RESULT;
999             send_gatt_read_characteristic_value_request(gatt_client);
1000             return 1;
1001 
1002         case P_W2_SEND_READ_BLOB_QUERY:
1003             gatt_client->gatt_client_state = P_W4_READ_BLOB_RESULT;
1004             send_gatt_read_blob_request(gatt_client);
1005             return 1;
1006 
1007         case P_W2_SEND_READ_BY_TYPE_REQUEST:
1008             gatt_client->gatt_client_state = P_W4_READ_BY_TYPE_RESPONSE;
1009             send_gatt_read_by_type_request(gatt_client);
1010             return 1;
1011 
1012         case P_W2_SEND_READ_MULTIPLE_REQUEST:
1013             gatt_client->gatt_client_state = P_W4_READ_MULTIPLE_RESPONSE;
1014             send_gatt_read_multiple_request(gatt_client);
1015             return 1;
1016 
1017         case P_W2_SEND_WRITE_CHARACTERISTIC_VALUE:
1018             gatt_client->gatt_client_state = P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT;
1019             send_gatt_write_attribute_value_request(gatt_client);
1020             return 1;
1021 
1022         case P_W2_PREPARE_WRITE:
1023             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_RESULT;
1024             send_gatt_prepare_write_request(gatt_client);
1025             return 1;
1026 
1027         case P_W2_PREPARE_WRITE_SINGLE:
1028             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_SINGLE_RESULT;
1029             send_gatt_prepare_write_request(gatt_client);
1030             return 1;
1031 
1032         case P_W2_PREPARE_RELIABLE_WRITE:
1033             gatt_client->gatt_client_state = P_W4_PREPARE_RELIABLE_WRITE_RESULT;
1034             send_gatt_prepare_write_request(gatt_client);
1035             return 1;
1036 
1037         case P_W2_EXECUTE_PREPARED_WRITE:
1038             gatt_client->gatt_client_state = P_W4_EXECUTE_PREPARED_WRITE_RESULT;
1039             send_gatt_execute_write_request(gatt_client);
1040             return 1;
1041 
1042         case P_W2_CANCEL_PREPARED_WRITE:
1043             gatt_client->gatt_client_state = P_W4_CANCEL_PREPARED_WRITE_RESULT;
1044             send_gatt_cancel_prepared_write_request(gatt_client);
1045             return 1;
1046 
1047         case P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH:
1048             gatt_client->gatt_client_state = P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT;
1049             send_gatt_cancel_prepared_write_request(gatt_client);
1050             return 1;
1051 
1052 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1053         case P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY:
1054             // use Find Information
1055             gatt_client->gatt_client_state = P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT;
1056             send_gatt_characteristic_descriptor_request(gatt_client);
1057 #else
1058         case P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY:
1059             // Use Read By Type
1060             gatt_client->gatt_client_state = P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT;
1061             send_gatt_read_client_characteristic_configuration_request(gatt_client);
1062 #endif
1063             return 1;
1064 
1065         case P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY:
1066             gatt_client->gatt_client_state = P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT;
1067             send_gatt_read_characteristic_descriptor_request(gatt_client);
1068             return 1;
1069 
1070         case P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY:
1071             gatt_client->gatt_client_state = P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT;
1072             send_gatt_read_blob_request(gatt_client);
1073             return 1;
1074 
1075         case P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR:
1076             gatt_client->gatt_client_state = P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1077             send_gatt_write_attribute_value_request(gatt_client);
1078             return 1;
1079 
1080         case P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION:
1081             gatt_client->gatt_client_state = P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT;
1082             send_gatt_write_client_characteristic_configuration_request(gatt_client);
1083             return 1;
1084 
1085         case P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR:
1086             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1087             send_gatt_prepare_write_request(gatt_client);
1088             return 1;
1089 
1090         case P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR:
1091             gatt_client->gatt_client_state = P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1092             send_gatt_execute_write_request(gatt_client);
1093             return 1;
1094 
1095 #ifdef ENABLE_LE_SIGNED_WRITE
1096         case P_W4_IDENTITY_RESOLVING:
1097             log_info("P_W4_IDENTITY_RESOLVING - state %x", sm_identity_resolving_state(gatt_client->con_handle));
1098             switch (sm_identity_resolving_state(gatt_client->con_handle)){
1099                 case IRK_LOOKUP_SUCCEEDED:
1100                     gatt_client->le_device_index = sm_le_device_index(gatt_client->con_handle);
1101                     gatt_client->gatt_client_state = P_W4_CMAC_READY;
1102                     break;
1103                 case IRK_LOOKUP_FAILED:
1104                     gatt_client_handle_transaction_complete(gatt_client);
1105                     emit_gatt_complete_event(gatt_client, ATT_ERROR_BONDING_INFORMATION_MISSING);
1106                     return 0;
1107                 default:
1108                     return 0;
1109             }
1110 
1111             /* Fall through */
1112 
1113         case P_W4_CMAC_READY:
1114             if (sm_cmac_ready()){
1115                 sm_key_t csrk;
1116                 le_device_db_local_csrk_get(gatt_client->le_device_index, csrk);
1117                 uint32_t sign_counter = le_device_db_local_counter_get(gatt_client->le_device_index);
1118                 gatt_client->gatt_client_state = P_W4_CMAC_RESULT;
1119                 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);
1120             }
1121             return 0;
1122 
1123         case P_W2_SEND_SIGNED_WRITE: {
1124             gatt_client->gatt_client_state = P_W4_SEND_SINGED_WRITE_DONE;
1125             // bump local signing counter
1126             uint32_t sign_counter = le_device_db_local_counter_get(gatt_client->le_device_index);
1127             le_device_db_local_counter_set(gatt_client->le_device_index, sign_counter + 1);
1128             // send signed write command
1129             send_gatt_signed_write_request(gatt_client, sign_counter);
1130             // finally, notifiy client that write is complete
1131             gatt_client_handle_transaction_complete(gatt_client);
1132             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1133             return 1;
1134         }
1135 #endif
1136         default:
1137             break;
1138     }
1139 
1140     // requested can send snow?
1141     if (gatt_client->write_without_response_callback){
1142         btstack_packet_handler_t packet_handler = gatt_client->write_without_response_callback;
1143         gatt_client->write_without_response_callback = NULL;
1144         uint8_t event[4];
1145         event[0] = GATT_EVENT_CAN_WRITE_WITHOUT_RESPONSE;
1146         event[1] = sizeof(event) - 2u;
1147         little_endian_store_16(event, 2, gatt_client->con_handle);
1148         packet_handler(HCI_EVENT_PACKET, gatt_client->con_handle, event, sizeof(event));
1149         return 1; // to trigger requeueing (even if higher layer didn't sent)
1150     }
1151 
1152     return 0;
1153 }
1154 
1155 static void gatt_client_run(void){
1156     btstack_linked_item_t *it;
1157     for (it = (btstack_linked_item_t *) gatt_client_connections; it != NULL; it = it->next){
1158         gatt_client_t * gatt_client = (gatt_client_t *) it;
1159         if (!att_dispatch_client_can_send_now(gatt_client->con_handle)) {
1160             att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
1161             return;
1162         }
1163         int packet_sent = gatt_client_run_for_gatt_client(gatt_client);
1164         if (packet_sent){
1165             // request new permission
1166             att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
1167             // requeue client for fairness and exit
1168             // note: iterator has become invalid
1169             btstack_linked_list_remove(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1170             btstack_linked_list_add_tail(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1171             return;
1172         }
1173     }
1174 }
1175 
1176 static void gatt_client_report_error_if_pending(gatt_client_t *gatt_client, uint8_t att_error_code) {
1177     if (is_ready(gatt_client) == 1) return;
1178     gatt_client_handle_transaction_complete(gatt_client);
1179     emit_gatt_complete_event(gatt_client, att_error_code);
1180 }
1181 
1182 static void gatt_client_event_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1183     UNUSED(channel);    // ok: handling own l2cap events
1184     UNUSED(size);       // ok: there is no channel
1185 
1186     if (packet_type != HCI_EVENT_PACKET) return;
1187 
1188     hci_con_handle_t con_handle;
1189     gatt_client_t * gatt_client;
1190     switch (hci_event_packet_get_type(packet)) {
1191         case HCI_EVENT_DISCONNECTION_COMPLETE:
1192             log_info("GATT Client: HCI_EVENT_DISCONNECTION_COMPLETE");
1193             con_handle = little_endian_read_16(packet,3);
1194             gatt_client = gatt_client_get_context_for_handle(con_handle);
1195             if (gatt_client == NULL) break;
1196 
1197             gatt_client_report_error_if_pending(gatt_client, ATT_ERROR_HCI_DISCONNECT_RECEIVED);
1198             gatt_client_timeout_stop(gatt_client);
1199             btstack_linked_list_remove(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1200             btstack_memory_gatt_client_free(gatt_client);
1201             break;
1202 
1203         // Pairing complete (with/without bonding=storing of pairing information)
1204         case SM_EVENT_PAIRING_COMPLETE:
1205             con_handle = sm_event_pairing_complete_get_handle(packet);
1206             gatt_client = gatt_client_get_context_for_handle(con_handle);
1207             if (gatt_client == NULL) break;
1208 
1209             // update security level
1210             gatt_client->security_level = gatt_client_le_security_level_for_connection(con_handle);
1211 
1212             if (gatt_client->wait_for_pairing_complete){
1213                 gatt_client->wait_for_pairing_complete = 0;
1214                 if (sm_event_pairing_complete_get_status(packet)){
1215                     log_info("pairing failed, report previous error 0x%x", gatt_client->pending_error_code);
1216                     gatt_client_report_error_if_pending(gatt_client, gatt_client->pending_error_code);
1217                 } else {
1218                     log_info("pairing success, retry operation");
1219                 }
1220             }
1221             break;
1222 
1223 #ifdef ENABLE_LE_SIGNED_WRITE
1224         // Identity Resolving completed (no code, gatt_client_run will continue)
1225         case SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED:
1226         case SM_EVENT_IDENTITY_RESOLVING_FAILED:
1227             break;
1228 #endif
1229 
1230         // re-encryption started
1231         case SM_EVENT_REENCRYPTION_STARTED:
1232             con_handle = sm_event_reencryption_complete_get_handle(packet);
1233             gatt_client = gatt_client_get_context_for_handle(con_handle);
1234             if (gatt_client == NULL) break;
1235 
1236             gatt_client->reencryption_active = true;
1237             gatt_client->reencryption_result = ERROR_CODE_SUCCESS;
1238             break;
1239 
1240         // re-encryption complete
1241         case SM_EVENT_REENCRYPTION_COMPLETE:
1242             con_handle = sm_event_reencryption_complete_get_handle(packet);
1243             gatt_client = gatt_client_get_context_for_handle(con_handle);
1244             if (gatt_client == NULL) break;
1245 
1246             // update security level
1247             gatt_client->security_level = gatt_client_le_security_level_for_connection(con_handle);
1248 
1249             gatt_client->reencryption_result = sm_event_reencryption_complete_get_status(packet);
1250             gatt_client->reencryption_active = false;
1251             break;
1252         default:
1253             break;
1254     }
1255 
1256     gatt_client_run();
1257 }
1258 
1259 static void gatt_client_att_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
1260     gatt_client_t * gatt_client;
1261     if (size < 1u) return;
1262 
1263     if (packet_type == HCI_EVENT_PACKET) {
1264         switch (packet[0]){
1265             case L2CAP_EVENT_CAN_SEND_NOW:
1266                 gatt_client_run();
1267                 break;
1268             // att_server has negotiated the mtu for this connection, cache if context exists
1269             case ATT_EVENT_MTU_EXCHANGE_COMPLETE:
1270                 if (size < 6u) break;
1271                 gatt_client = gatt_client_get_context_for_handle(handle);
1272                 if (gatt_client == NULL) break;
1273                 gatt_client->mtu = little_endian_read_16(packet, 4);
1274                 break;
1275             default:
1276                 break;
1277         }
1278         return;
1279     }
1280 
1281     if (packet_type != ATT_DATA_PACKET) return;
1282 
1283     // special cases: notifications don't need a context while indications motivate creating one
1284     switch (packet[0]){
1285         case ATT_HANDLE_VALUE_NOTIFICATION:
1286             if (size < 3u) return;
1287             report_gatt_notification(handle, little_endian_read_16(packet,1u), &packet[3], size-3u);
1288             return;
1289         case ATT_HANDLE_VALUE_INDICATION:
1290             gatt_client = gatt_client_provide_context_for_handle(handle);
1291             break;
1292         default:
1293             gatt_client = gatt_client_get_context_for_handle(handle);
1294             break;
1295     }
1296 
1297     if (gatt_client == NULL) return;
1298 
1299     uint8_t error_code;
1300     switch (packet[0]){
1301         case ATT_EXCHANGE_MTU_RESPONSE:
1302         {
1303             if (size < 3u) break;
1304             uint16_t remote_rx_mtu = little_endian_read_16(packet, 1);
1305             uint16_t local_rx_mtu = l2cap_max_le_mtu();
1306             gatt_client->mtu = (remote_rx_mtu < local_rx_mtu) ? remote_rx_mtu : local_rx_mtu;
1307             gatt_client->mtu_state = MTU_EXCHANGED;
1308             emit_gatt_mtu_exchanged_result_event(gatt_client, gatt_client->mtu);
1309             break;
1310         }
1311         case ATT_READ_BY_GROUP_TYPE_RESPONSE:
1312             switch(gatt_client->gatt_client_state){
1313                 case P_W4_SERVICE_QUERY_RESULT:
1314                     report_gatt_services(gatt_client, packet, size);
1315                     trigger_next_service_query(gatt_client, get_last_result_handle_from_service_list(packet, size));
1316                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1317                     break;
1318                 default:
1319                     break;
1320             }
1321             break;
1322         case ATT_HANDLE_VALUE_INDICATION:
1323             if (size < 3u) break;
1324             report_gatt_indication(handle, little_endian_read_16(packet,1u), &packet[3], size-3u);
1325             gatt_client->send_confirmation = 1;
1326             break;
1327 
1328         case ATT_READ_BY_TYPE_RESPONSE:
1329             switch (gatt_client->gatt_client_state){
1330                 case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1331                     report_gatt_characteristics(gatt_client, packet, size);
1332                     trigger_next_characteristic_query(gatt_client, get_last_result_handle_from_characteristics_list(packet, size));
1333                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1334                     break;
1335                 case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1336                     report_gatt_characteristics(gatt_client, packet, size);
1337                     trigger_next_characteristic_query(gatt_client, get_last_result_handle_from_characteristics_list(packet, size));
1338                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1339                     break;
1340                 case P_W4_INCLUDED_SERVICE_QUERY_RESULT:
1341                 {
1342                     if (size < 2u) break;
1343                     uint16_t uuid16 = 0;
1344                     uint16_t pair_size = packet[1];
1345 
1346                     if (pair_size == 6u){
1347                         if (size < 8u) break;
1348                         // UUIDs not available, query first included service
1349                         gatt_client->start_group_handle = little_endian_read_16(packet, 2); // ready for next query
1350                         gatt_client->query_start_handle = little_endian_read_16(packet, 4);
1351                         gatt_client->query_end_handle = little_endian_read_16(packet, 6);
1352                         gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY;
1353                         break;
1354                     }
1355 
1356                     if (pair_size != 8u) break;
1357 
1358                     // UUIDs included, report all of them
1359                     uint16_t offset;
1360                     for (offset = 2u; (offset + 8u) <= size; offset += pair_size){
1361                         uint16_t include_handle = little_endian_read_16(packet, offset);
1362                         gatt_client->query_start_handle = little_endian_read_16(packet, offset + 2u);
1363                         gatt_client->query_end_handle = little_endian_read_16(packet, offset + 4u);
1364                         uuid16 = little_endian_read_16(packet, offset+6u);
1365                         report_gatt_included_service_uuid16(gatt_client, include_handle, uuid16);
1366                     }
1367 
1368                     trigger_next_included_service_query(gatt_client, get_last_result_handle_from_included_services_list(packet, size));
1369                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1370                     break;
1371                 }
1372 #ifndef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1373                 case P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT:
1374                     gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, 2);
1375                     gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1376                     break;
1377 #endif
1378                 case P_W4_READ_BY_TYPE_RESPONSE: {
1379                     uint16_t pair_size = packet[1];
1380                     uint16_t offset;
1381                     uint16_t last_result_handle = 0;
1382                     for (offset = 2; offset < size ; offset += pair_size){
1383                         uint16_t value_handle = little_endian_read_16(packet, offset);
1384                         report_gatt_characteristic_value(gatt_client, value_handle, &packet[offset + 2u], pair_size - 2u);
1385                         last_result_handle = value_handle;
1386                     }
1387                     trigger_next_read_by_type_query(gatt_client, last_result_handle);
1388                     break;
1389                 }
1390                 default:
1391                     break;
1392             }
1393             break;
1394         case ATT_READ_RESPONSE:
1395             switch (gatt_client->gatt_client_state){
1396                 case P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT: {
1397                     uint8_t uuid128[16];
1398                     reverse_128(&packet[1], uuid128);
1399                     report_gatt_included_service_uuid128(gatt_client, gatt_client->start_group_handle, uuid128);
1400                     trigger_next_included_service_query(gatt_client, gatt_client->start_group_handle);
1401                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1402                     break;
1403                 }
1404                 case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1405                     gatt_client_handle_transaction_complete(gatt_client);
1406                     report_gatt_characteristic_value(gatt_client, gatt_client->attribute_handle, &packet[1], size - 1u);
1407                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1408                     break;
1409 
1410                 case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:{
1411                     gatt_client_handle_transaction_complete(gatt_client);
1412                     report_gatt_characteristic_descriptor(gatt_client, gatt_client->attribute_handle, &packet[1], size - 1u, 0u);
1413                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1414                     break;
1415                 }
1416                 default:
1417                     break;
1418             }
1419             break;
1420 
1421         case ATT_FIND_BY_TYPE_VALUE_RESPONSE:
1422         {
1423             uint8_t pair_size = 4;
1424             int i;
1425             uint16_t start_group_handle;
1426             uint16_t   end_group_handle= 0xffff; // asserts GATT_EVENT_QUERY_COMPLETE is emitted if no results
1427             for (i = 1u; (i + pair_size) <= size; i += pair_size){
1428                 start_group_handle = little_endian_read_16(packet,i);
1429                 end_group_handle = little_endian_read_16(packet,i+2);
1430                 emit_gatt_service_query_result_event(gatt_client, start_group_handle, end_group_handle, gatt_client->uuid128);
1431             }
1432             trigger_next_service_by_uuid_query(gatt_client, end_group_handle);
1433             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1434             break;
1435         }
1436         case ATT_FIND_INFORMATION_REPLY:
1437         {
1438             if (size < 2u) break;
1439 
1440             uint8_t pair_size = 4;
1441             if (packet[1u] == 2u){
1442                 pair_size = 18;
1443             }
1444             uint16_t offset = 2;
1445 
1446             if (size < (pair_size + offset)) break;
1447             uint16_t last_descriptor_handle = little_endian_read_16(packet, size - pair_size);
1448 
1449 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1450             log_info("ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY, state %x", gatt_client->gatt_client_state);
1451             if (gatt_client->gatt_client_state == P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT){
1452                 // iterate over descriptors looking for CCC
1453                 if (pair_size == 4){
1454                     while ((offset + 4) <= size){
1455                         uint16_t uuid16 = little_endian_read_16(packet, offset + 2);
1456                         if (uuid16 == GATT_CLIENT_CHARACTERISTICS_CONFIGURATION){
1457                             gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, offset);
1458                             gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1459                             log_info("CCC found %x", gatt_client->client_characteristic_configuration_handle);
1460                             break;
1461                         }
1462                         offset += pair_size;
1463                     }
1464                 }
1465                 if (is_query_done(gatt_client, last_descriptor_handle)){
1466 
1467                 } else {
1468                     // next
1469                     gatt_client->start_group_handle = last_descriptor_handle + 1;
1470                     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
1471                 }
1472                 break;
1473             }
1474 #endif
1475             report_gatt_all_characteristic_descriptors(gatt_client, &packet[2], size - 2u, pair_size);
1476             trigger_next_characteristic_descriptor_query(gatt_client, last_descriptor_handle);
1477             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1478             break;
1479         }
1480 
1481         case ATT_WRITE_RESPONSE:
1482             switch (gatt_client->gatt_client_state){
1483                 case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1484                     gatt_client_handle_transaction_complete(gatt_client);
1485                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1486                     break;
1487                 case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1488                     gatt_client_handle_transaction_complete(gatt_client);
1489                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1490                     break;
1491                 case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1492                     gatt_client_handle_transaction_complete(gatt_client);
1493                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1494                     break;
1495                 default:
1496                     break;
1497             }
1498             break;
1499 
1500         case ATT_READ_BLOB_RESPONSE:{
1501             uint16_t received_blob_length = size-1u;
1502             switch(gatt_client->gatt_client_state){
1503                 case P_W4_READ_BLOB_RESULT:
1504                     report_gatt_long_characteristic_value_blob(gatt_client, gatt_client->attribute_handle, &packet[1], received_blob_length, gatt_client->attribute_offset);
1505                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_QUERY, received_blob_length);
1506                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1507                     break;
1508                 case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1509                     report_gatt_long_characteristic_descriptor(gatt_client, gatt_client->attribute_handle,
1510                                                                &packet[1], received_blob_length,
1511                                                                gatt_client->attribute_offset);
1512                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY, received_blob_length);
1513                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1514                     break;
1515                 default:
1516                     break;
1517             }
1518             break;
1519         }
1520         case ATT_PREPARE_WRITE_RESPONSE:
1521             switch (gatt_client->gatt_client_state){
1522                 case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1523                     gatt_client_handle_transaction_complete(gatt_client);
1524                     if (is_value_valid(gatt_client, packet, size)){
1525                         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1526                     } else {
1527                         emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1528                     }
1529                     break;
1530 
1531                 case P_W4_PREPARE_WRITE_RESULT:{
1532                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1533                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE, P_W2_EXECUTE_PREPARED_WRITE);
1534                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1535                     break;
1536                 }
1537                 case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:{
1538                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1539                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR, P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR);
1540                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1541                     break;
1542                 }
1543                 case P_W4_PREPARE_RELIABLE_WRITE_RESULT:{
1544                     if (is_value_valid(gatt_client, packet, size)){
1545                         gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1546                         trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_RELIABLE_WRITE, P_W2_EXECUTE_PREPARED_WRITE);
1547                         // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1548                         break;
1549                     }
1550                     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1551                     break;
1552                 }
1553                 default:
1554                     break;
1555             }
1556             break;
1557 
1558         case ATT_EXECUTE_WRITE_RESPONSE:
1559             switch (gatt_client->gatt_client_state){
1560                 case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1561                     gatt_client_handle_transaction_complete(gatt_client);
1562                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1563                     break;
1564                 case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1565                     gatt_client_handle_transaction_complete(gatt_client);
1566                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1567                     break;
1568                 case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1569                     gatt_client_handle_transaction_complete(gatt_client);
1570                     emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1571                     break;
1572                 case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1573                     gatt_client_handle_transaction_complete(gatt_client);
1574                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1575                     break;
1576                 default:
1577                     break;
1578 
1579             }
1580             break;
1581 
1582         case ATT_READ_MULTIPLE_RESPONSE:
1583             switch(gatt_client->gatt_client_state){
1584                 case P_W4_READ_MULTIPLE_RESPONSE:
1585                     report_gatt_characteristic_value(gatt_client, 0u, &packet[1], size - 1u);
1586                     gatt_client_handle_transaction_complete(gatt_client);
1587                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1588                     break;
1589                 default:
1590                     break;
1591             }
1592             break;
1593 
1594         case ATT_ERROR_RESPONSE:
1595             if (size < 5u) return;
1596             error_code = packet[4];
1597             switch (error_code){
1598                 case ATT_ERROR_ATTRIBUTE_NOT_FOUND: {
1599                     switch(gatt_client->gatt_client_state){
1600                         case P_W4_SERVICE_QUERY_RESULT:
1601                         case P_W4_SERVICE_WITH_UUID_RESULT:
1602                         case P_W4_INCLUDED_SERVICE_QUERY_RESULT:
1603                         case P_W4_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT:
1604                             gatt_client_handle_transaction_complete(gatt_client);
1605                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1606                             break;
1607                         case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1608                         case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1609                             characteristic_end_found(gatt_client, gatt_client->end_group_handle);
1610                             gatt_client_handle_transaction_complete(gatt_client);
1611                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1612                             break;
1613                         case P_W4_READ_BY_TYPE_RESPONSE:
1614                             gatt_client_handle_transaction_complete(gatt_client);
1615                             if (gatt_client->start_group_handle == gatt_client->query_start_handle){
1616                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_ATTRIBUTE_NOT_FOUND);
1617                             } else {
1618                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1619                             }
1620                             break;
1621                         default:
1622                             gatt_client_report_error_if_pending(gatt_client, error_code);
1623                             break;
1624                     }
1625                     break;
1626                 }
1627 
1628 #ifdef ENABLE_GATT_CLIENT_PAIRING
1629 
1630                 case ATT_ERROR_INSUFFICIENT_AUTHENTICATION:
1631                 case ATT_ERROR_INSUFFICIENT_ENCRYPTION_KEY_SIZE:
1632                 case ATT_ERROR_INSUFFICIENT_ENCRYPTION: {
1633 
1634                     // security too low
1635                     if (gatt_client->security_counter > 0) {
1636                         gatt_client_report_error_if_pending(gatt_client, error_code);
1637                         break;
1638                     }
1639                     // start security
1640                     gatt_client->security_counter++;
1641 
1642                     // setup action
1643                     int retry = 1;
1644                     switch (gatt_client->gatt_client_state){
1645                         case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1646                             gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY ;
1647                             break;
1648                         case P_W4_READ_BLOB_RESULT:
1649                             gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
1650                             break;
1651                         case P_W4_READ_BY_TYPE_RESPONSE:
1652                             gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1653                             break;
1654                         case P_W4_READ_MULTIPLE_RESPONSE:
1655                             gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
1656                             break;
1657                         case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1658                             gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
1659                             break;
1660                         case P_W4_PREPARE_WRITE_RESULT:
1661                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
1662                             break;
1663                         case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1664                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
1665                             break;
1666                         case P_W4_PREPARE_RELIABLE_WRITE_RESULT:
1667                             gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
1668                             break;
1669                         case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1670                             gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
1671                             break;
1672                         case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1673                             gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
1674                             break;
1675                         case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1676                             gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1677                             break;
1678                         case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:
1679                             gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
1680                             break;
1681                         case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1682                             gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
1683                             break;
1684                         case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1685                             gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
1686                             break;
1687                         case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1688                             gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1689                             break;
1690                         case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1691                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
1692                             break;
1693                         case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1694                             gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR;
1695                             break;
1696 #ifdef ENABLE_LE_SIGNED_WRITE
1697                         case P_W4_SEND_SINGED_WRITE_DONE:
1698                             gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1699                             break;
1700 #endif
1701                         default:
1702                             log_info("retry not supported for state %x", gatt_client->gatt_client_state);
1703                             retry = 0;
1704                             break;
1705                     }
1706 
1707                     if (!retry) {
1708                         gatt_client_report_error_if_pending(gatt_client, error_code);
1709                         break;
1710                     }
1711 
1712                     log_info("security error, start pairing");
1713 
1714                     // start pairing for higher security level
1715                     gatt_client->wait_for_pairing_complete = 1;
1716                     gatt_client->pending_error_code = error_code;
1717                     sm_request_pairing(gatt_client->con_handle);
1718                     break;
1719                 }
1720 #endif
1721 
1722                 // nothing we can do about that
1723                 case ATT_ERROR_INSUFFICIENT_AUTHORIZATION:
1724                 default:
1725                     gatt_client_report_error_if_pending(gatt_client, error_code);
1726                     break;
1727             }
1728             break;
1729 
1730         default:
1731             log_info("ATT Handler, unhandled response type 0x%02x", packet[0]);
1732             break;
1733     }
1734     gatt_client_run();
1735 }
1736 
1737 #ifdef ENABLE_LE_SIGNED_WRITE
1738 static void att_signed_write_handle_cmac_result(uint8_t hash[8]){
1739     btstack_linked_list_iterator_t it;
1740     btstack_linked_list_iterator_init(&it, &gatt_client_connections);
1741     while (btstack_linked_list_iterator_has_next(&it)){
1742         gatt_client_t * gatt_client = (gatt_client_t *) btstack_linked_list_iterator_next(&it);
1743         if (gatt_client->gatt_client_state == P_W4_CMAC_RESULT){
1744             // store result
1745             (void)memcpy(gatt_client->cmac, hash, 8);
1746             // reverse_64(hash, gatt_client->cmac);
1747             gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1748             gatt_client_run();
1749             return;
1750         }
1751     }
1752 }
1753 
1754 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){
1755     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
1756     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1757     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1758 
1759     gatt_client->callback = callback;
1760     gatt_client->attribute_handle = handle;
1761     gatt_client->attribute_length = message_len;
1762     gatt_client->attribute_value = message;
1763     gatt_client->gatt_client_state = P_W4_IDENTITY_RESOLVING;
1764     gatt_client_run();
1765     return ERROR_CODE_SUCCESS;
1766 }
1767 #endif
1768 
1769 uint8_t gatt_client_discover_primary_services(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
1770     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1771     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1772     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1773 
1774     gatt_client->callback = callback;
1775     gatt_client->start_group_handle = 0x0001;
1776     gatt_client->end_group_handle   = 0xffff;
1777     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_QUERY;
1778     gatt_client->uuid16 = 0;
1779     gatt_client_run();
1780     return ERROR_CODE_SUCCESS;
1781 }
1782 
1783 
1784 uint8_t gatt_client_discover_primary_services_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t uuid16){
1785     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1786     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1787     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1788 
1789     gatt_client->callback = callback;
1790     gatt_client->start_group_handle = 0x0001;
1791     gatt_client->end_group_handle   = 0xffff;
1792     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
1793     gatt_client->uuid16 = uuid16;
1794     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), gatt_client->uuid16);
1795     gatt_client_run();
1796     return ERROR_CODE_SUCCESS;
1797 }
1798 
1799 uint8_t gatt_client_discover_primary_services_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, const uint8_t * uuid128){
1800     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1801     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1802     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1803 
1804     gatt_client->callback = callback;
1805     gatt_client->start_group_handle = 0x0001;
1806     gatt_client->end_group_handle   = 0xffff;
1807     gatt_client->uuid16 = 0;
1808     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1809     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
1810     gatt_client_run();
1811     return ERROR_CODE_SUCCESS;
1812 }
1813 
1814 uint8_t gatt_client_discover_characteristics_for_service(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t *service){
1815     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1816     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1817     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1818 
1819     gatt_client->callback = callback;
1820     gatt_client->start_group_handle = service->start_group_handle;
1821     gatt_client->end_group_handle   = service->end_group_handle;
1822     gatt_client->filter_with_uuid = 0;
1823     gatt_client->characteristic_start_handle = 0;
1824     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY;
1825     gatt_client_run();
1826     return ERROR_CODE_SUCCESS;
1827 }
1828 
1829 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){
1830     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1831     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1832     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1833     gatt_client->callback = callback;
1834     gatt_client->start_group_handle = service->start_group_handle;
1835     gatt_client->end_group_handle   = service->end_group_handle;
1836     gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_QUERY;
1837 
1838     gatt_client_run();
1839     return ERROR_CODE_SUCCESS;
1840 }
1841 
1842 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){
1843     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1844     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1845     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1846 
1847     gatt_client->callback = callback;
1848     gatt_client->start_group_handle = start_handle;
1849     gatt_client->end_group_handle   = end_handle;
1850     gatt_client->filter_with_uuid = 1;
1851     gatt_client->uuid16 = uuid16;
1852     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
1853     gatt_client->characteristic_start_handle = 0;
1854     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
1855     gatt_client_run();
1856     return ERROR_CODE_SUCCESS;
1857 }
1858 
1859 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){
1860     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1861     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1862     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1863 
1864     gatt_client->callback = callback;
1865     gatt_client->start_group_handle = start_handle;
1866     gatt_client->end_group_handle   = end_handle;
1867     gatt_client->filter_with_uuid = 1;
1868     gatt_client->uuid16 = 0;
1869     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1870     gatt_client->characteristic_start_handle = 0;
1871     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
1872     gatt_client_run();
1873     return ERROR_CODE_SUCCESS;
1874 }
1875 
1876 
1877 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){
1878     return gatt_client_discover_characteristics_for_handle_range_by_uuid16(callback, handle, service->start_group_handle, service->end_group_handle, uuid16);
1879 }
1880 
1881 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){
1882     return gatt_client_discover_characteristics_for_handle_range_by_uuid128(callback, handle, service->start_group_handle, service->end_group_handle, uuid128);
1883 }
1884 
1885 uint8_t gatt_client_discover_characteristic_descriptors(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t *characteristic){
1886     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1887     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1888     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1889 
1890     if (characteristic->value_handle == characteristic->end_handle){
1891         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1892         return ERROR_CODE_SUCCESS;
1893     }
1894     gatt_client->callback = callback;
1895     gatt_client->start_group_handle = characteristic->value_handle + 1u;
1896     gatt_client->end_group_handle   = characteristic->end_handle;
1897     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY;
1898     gatt_client_run();
1899     return ERROR_CODE_SUCCESS;
1900 }
1901 
1902 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){
1903     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1904     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1905     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1906 
1907     gatt_client->callback = callback;
1908     gatt_client->attribute_handle = value_handle;
1909     gatt_client->attribute_offset = 0;
1910     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY;
1911     gatt_client_run();
1912     return ERROR_CODE_SUCCESS;
1913 }
1914 
1915 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){
1916     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1917     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1918     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1919 
1920     gatt_client->callback = callback;
1921     gatt_client->start_group_handle = start_handle;
1922     gatt_client->end_group_handle = end_handle;
1923     gatt_client->query_start_handle = start_handle;
1924     gatt_client->query_end_handle = end_handle;
1925     gatt_client->uuid16 = uuid16;
1926     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
1927     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1928     gatt_client_run();
1929     return ERROR_CODE_SUCCESS;
1930 }
1931 
1932 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){
1933     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1934     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1935     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1936 
1937     gatt_client->callback = callback;
1938     gatt_client->start_group_handle = start_handle;
1939     gatt_client->end_group_handle = end_handle;
1940     gatt_client->query_start_handle = start_handle;
1941     gatt_client->query_end_handle = end_handle;
1942     gatt_client->uuid16 = 0;
1943     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1944     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1945     gatt_client_run();
1946     return ERROR_CODE_SUCCESS;
1947 }
1948 
1949 
1950 uint8_t gatt_client_read_value_of_characteristic(btstack_packet_handler_t callback, uint16_t handle, gatt_client_characteristic_t *characteristic){
1951     return gatt_client_read_value_of_characteristic_using_value_handle(callback, handle, characteristic->value_handle);
1952 }
1953 
1954 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){
1955     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1956     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1957     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1958 
1959     gatt_client->callback = callback;
1960     gatt_client->attribute_handle = characteristic_value_handle;
1961     gatt_client->attribute_offset = offset;
1962     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
1963     gatt_client_run();
1964     return ERROR_CODE_SUCCESS;
1965 }
1966 
1967 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){
1968     return gatt_client_read_long_value_of_characteristic_using_value_handle_with_offset(callback, con_handle, characteristic_value_handle, 0);
1969 }
1970 
1971 uint8_t gatt_client_read_long_value_of_characteristic(btstack_packet_handler_t callback, uint16_t handle, gatt_client_characteristic_t *characteristic){
1972     return gatt_client_read_long_value_of_characteristic_using_value_handle(callback, handle, characteristic->value_handle);
1973 }
1974 
1975 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){
1976     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1977     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1978     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1979 
1980     gatt_client->callback = callback;
1981     gatt_client->read_multiple_handle_count = num_value_handles;
1982     gatt_client->read_multiple_handles = value_handles;
1983     gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
1984     gatt_client_run();
1985     return ERROR_CODE_SUCCESS;
1986 }
1987 
1988 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){
1989     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
1990     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1991 
1992     if (value_length > (gatt_client->mtu - 3u)) return GATT_CLIENT_VALUE_TOO_LONG;
1993     if (!att_dispatch_client_can_send_now(gatt_client->con_handle)) return GATT_CLIENT_BUSY;
1994 
1995     return att_write_request(ATT_WRITE_COMMAND, gatt_client->con_handle, value_handle, value_length, value);
1996 }
1997 
1998 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){
1999     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2000     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2001     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2002 
2003     gatt_client->callback = callback;
2004     gatt_client->attribute_handle = value_handle;
2005     gatt_client->attribute_length = value_length;
2006     gatt_client->attribute_value = data;
2007     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
2008     gatt_client_run();
2009     return ERROR_CODE_SUCCESS;
2010 }
2011 
2012 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){
2013     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2014     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2015     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2016 
2017     gatt_client->callback = callback;
2018     gatt_client->attribute_handle = value_handle;
2019     gatt_client->attribute_length = value_length;
2020     gatt_client->attribute_offset = offset;
2021     gatt_client->attribute_value = data;
2022     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
2023     gatt_client_run();
2024     return ERROR_CODE_SUCCESS;
2025 }
2026 
2027 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){
2028     return gatt_client_write_long_value_of_characteristic_with_offset(callback, con_handle, value_handle, 0, value_length, value);
2029 }
2030 
2031 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){
2032     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2033     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2034     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2035 
2036     gatt_client->callback = callback;
2037     gatt_client->attribute_handle = value_handle;
2038     gatt_client->attribute_length = value_length;
2039     gatt_client->attribute_offset = 0;
2040     gatt_client->attribute_value = value;
2041     gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
2042     gatt_client_run();
2043     return ERROR_CODE_SUCCESS;
2044 }
2045 
2046 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){
2047     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2048     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2049     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2050 
2051     if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION) &&
2052         ((characteristic->properties & ATT_PROPERTY_NOTIFY) == 0u)) {
2053         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED");
2054         return GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED;
2055     } else if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_INDICATION) &&
2056                ((characteristic->properties & ATT_PROPERTY_INDICATE) == 0u)){
2057         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED");
2058         return GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED;
2059     }
2060 
2061     gatt_client->callback = callback;
2062     gatt_client->start_group_handle = characteristic->value_handle;
2063     gatt_client->end_group_handle = characteristic->end_handle;
2064     little_endian_store_16(gatt_client->client_characteristic_configuration_value, 0, configuration);
2065 
2066 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
2067     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
2068 #else
2069     gatt_client->gatt_client_state = P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
2070 #endif
2071     gatt_client_run();
2072     return ERROR_CODE_SUCCESS;
2073 }
2074 
2075 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){
2076     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2077     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2078     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2079 
2080     gatt_client->callback = callback;
2081     gatt_client->attribute_handle = descriptor_handle;
2082 
2083     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
2084     gatt_client_run();
2085     return ERROR_CODE_SUCCESS;
2086 }
2087 
2088 uint8_t gatt_client_read_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t * descriptor){
2089     return gatt_client_read_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
2090 }
2091 
2092 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){
2093     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2094     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2095     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2096 
2097     gatt_client->callback = callback;
2098     gatt_client->attribute_handle = descriptor_handle;
2099     gatt_client->attribute_offset = offset;
2100     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
2101     gatt_client_run();
2102     return ERROR_CODE_SUCCESS;
2103 }
2104 
2105 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){
2106     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0);
2107 }
2108 
2109 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){
2110     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
2111 }
2112 
2113 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){
2114     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2115     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2116     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2117 
2118     gatt_client->callback = callback;
2119     gatt_client->attribute_handle = descriptor_handle;
2120     gatt_client->attribute_length = length;
2121     gatt_client->attribute_offset = 0;
2122     gatt_client->attribute_value = data;
2123     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
2124     gatt_client_run();
2125     return ERROR_CODE_SUCCESS;
2126 }
2127 
2128 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){
2129     return gatt_client_write_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, length, value);
2130 }
2131 
2132 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){
2133     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2134     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2135     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2136 
2137     gatt_client->callback = callback;
2138     gatt_client->attribute_handle = descriptor_handle;
2139     gatt_client->attribute_length = length;
2140     gatt_client->attribute_offset = offset;
2141     gatt_client->attribute_value = data;
2142     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
2143     gatt_client_run();
2144     return ERROR_CODE_SUCCESS;
2145 }
2146 
2147 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){
2148     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0, length, data );
2149 }
2150 
2151 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){
2152     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, length, value);
2153 }
2154 
2155 /**
2156  * @brief -> gatt complete event
2157  */
2158 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){
2159     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2160     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2161     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2162 
2163     gatt_client->callback = callback;
2164     gatt_client->attribute_handle = attribute_handle;
2165     gatt_client->attribute_length = length;
2166     gatt_client->attribute_offset = offset;
2167     gatt_client->attribute_value = data;
2168     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
2169     gatt_client_run();
2170     return ERROR_CODE_SUCCESS;
2171 }
2172 
2173 /**
2174  * @brief -> gatt complete event
2175  */
2176 uint8_t gatt_client_execute_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2177     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2178 
2179     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2180     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2181 
2182     gatt_client->callback = callback;
2183     gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
2184     gatt_client_run();
2185     return ERROR_CODE_SUCCESS;
2186 }
2187 
2188 /**
2189  * @brief -> gatt complete event
2190  */
2191 uint8_t gatt_client_cancel_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2192     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2193     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2194     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2195 
2196     gatt_client->callback = callback;
2197     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
2198     gatt_client_run();
2199     return ERROR_CODE_SUCCESS;
2200 }
2201 
2202 void gatt_client_deserialize_service(const uint8_t *packet, int offset, gatt_client_service_t *service){
2203     service->start_group_handle = little_endian_read_16(packet, offset);
2204     service->end_group_handle = little_endian_read_16(packet, offset + 2);
2205     reverse_128(&packet[offset + 4], service->uuid128);
2206     if (uuid_has_bluetooth_prefix(service->uuid128)){
2207         service->uuid16 = big_endian_read_32(service->uuid128, 0);
2208     } else {
2209         service->uuid16 = 0;
2210     }
2211 }
2212 
2213 void gatt_client_deserialize_characteristic(const uint8_t * packet, int offset, gatt_client_characteristic_t * characteristic){
2214     characteristic->start_handle = little_endian_read_16(packet, offset);
2215     characteristic->value_handle = little_endian_read_16(packet, offset + 2);
2216     characteristic->end_handle = little_endian_read_16(packet, offset + 4);
2217     characteristic->properties = little_endian_read_16(packet, offset + 6);
2218     reverse_128(&packet[offset+8], characteristic->uuid128);
2219     if (uuid_has_bluetooth_prefix(characteristic->uuid128)){
2220         characteristic->uuid16 = big_endian_read_32(characteristic->uuid128, 0);
2221     } else {
2222         characteristic->uuid16 = 0;
2223     }
2224 }
2225 
2226 void gatt_client_deserialize_characteristic_descriptor(const uint8_t * packet, int offset, gatt_client_characteristic_descriptor_t * descriptor){
2227     descriptor->handle = little_endian_read_16(packet, offset);
2228     reverse_128(&packet[offset+2], descriptor->uuid128);
2229     if (uuid_has_bluetooth_prefix(descriptor->uuid128)){
2230         descriptor->uuid16 = big_endian_read_32(descriptor->uuid128, 0);
2231     } else {
2232         descriptor->uuid16 = 0;
2233     }
2234 }
2235 
2236 void gatt_client_send_mtu_negotiation(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2237     gatt_client_t * context = gatt_client_provide_context_for_handle(con_handle);
2238     if (context == NULL) return;
2239     if (context->mtu_state == MTU_AUTO_EXCHANGE_DISABLED){
2240         context->callback = callback;
2241         context->mtu_state = SEND_MTU_EXCHANGE;
2242         gatt_client_run();
2243     }
2244 }
2245 
2246 uint8_t gatt_client_request_can_write_without_response_event(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2247     gatt_client_t * context = gatt_client_provide_context_for_handle(con_handle);
2248     if (context == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2249     if (context->write_without_response_callback != NULL) return GATT_CLIENT_IN_WRONG_STATE;
2250     context->write_without_response_callback = callback;
2251     att_dispatch_client_request_can_send_now_event(context->con_handle);
2252     return ERROR_CODE_SUCCESS;
2253 }
2254 
2255 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
2256 void gatt_client_att_packet_handler_fuzz(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
2257     gatt_client_att_packet_handler(packet_type, handle, packet, size);
2258 }
2259 #endif
2260