xref: /btstack/src/ble/gatt_client.c (revision dda77937c128dbfedaed0e4ad37ce6631b36ce35)
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 
43 #include "btstack_config.h"
44 
45 #include "att_dispatch.h"
46 #include "ad_parser.h"
47 #include "ble/att_db.h"
48 #include "ble/core.h"
49 #include "ble/gatt_client.h"
50 #include "ble/le_device_db.h"
51 #include "ble/sm.h"
52 #include "btstack_debug.h"
53 #include "btstack_event.h"
54 #include "btstack_memory.h"
55 #include "btstack_run_loop.h"
56 #include "btstack_util.h"
57 #include "classic/sdp_util.h"
58 #include "hci.h"
59 #include "hci_cmd.h"
60 #include "hci_dump.h"
61 #include "l2cap.h"
62 
63 static btstack_linked_list_t gatt_client_connections;
64 static btstack_linked_list_t gatt_client_value_listeners;
65 static btstack_packet_callback_registration_t hci_event_callback_registration;
66 
67 #if defined(ENABLE_GATT_CLIENT_PAIRING) || defined (ENABLE_LE_SIGNED_WRITE)
68 static btstack_packet_callback_registration_t sm_event_callback_registration;
69 #endif
70 
71 static uint8_t mtu_exchange_enabled;
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     mtu_exchange_enabled = 1;
84 
85     // regsister for HCI Events
86     hci_event_callback_registration.callback = &gatt_client_event_packet_handler;
87     hci_add_event_handler(&hci_event_callback_registration);
88 
89 #if defined(ENABLE_GATT_CLIENT_PAIRING) || defined (ENABLE_LE_SIGNED_WRITE)
90     // register for SM Events
91     sm_event_callback_registration.callback = &gatt_client_event_packet_handler;
92     sm_add_event_handler(&sm_event_callback_registration);
93 #endif
94 
95     // and ATT Client PDUs
96     att_dispatch_register_client(gatt_client_att_packet_handler);
97 }
98 
99 static gatt_client_t * gatt_client_for_timer(btstack_timer_source_t * ts){
100     btstack_linked_list_iterator_t it;
101     btstack_linked_list_iterator_init(&it, &gatt_client_connections);
102     while (btstack_linked_list_iterator_has_next(&it)){
103         gatt_client_t * gatt_client = (gatt_client_t *) btstack_linked_list_iterator_next(&it);
104         if (&gatt_client->gc_timeout == ts) {
105             return gatt_client;
106         }
107     }
108     return NULL;
109 }
110 
111 static void gatt_client_timeout_handler(btstack_timer_source_t * timer){
112     gatt_client_t * gatt_client = gatt_client_for_timer(timer);
113     if (gatt_client == NULL) return;
114     log_info("GATT client timeout handle, handle 0x%02x", gatt_client->con_handle);
115     gatt_client_report_error_if_pending(gatt_client, ATT_ERROR_TIMEOUT);
116 }
117 
118 static void gatt_client_timeout_start(gatt_client_t * gatt_client){
119     log_info("GATT client timeout start, handle 0x%02x", gatt_client->con_handle);
120     btstack_run_loop_remove_timer(&gatt_client->gc_timeout);
121     btstack_run_loop_set_timer_handler(&gatt_client->gc_timeout, gatt_client_timeout_handler);
122     btstack_run_loop_set_timer(&gatt_client->gc_timeout, 30000); // 30 seconds sm timeout
123     btstack_run_loop_add_timer(&gatt_client->gc_timeout);
124 }
125 
126 static void gatt_client_timeout_stop(gatt_client_t * gatt_client){
127     log_info("GATT client timeout stop, handle 0x%02x", gatt_client->con_handle);
128     btstack_run_loop_remove_timer(&gatt_client->gc_timeout);
129 }
130 
131 static gatt_client_t * gatt_client_get_context_for_handle(uint16_t handle){
132     btstack_linked_item_t *it;
133     for (it = (btstack_linked_item_t *) gatt_client_connections; it != NULL; it = it->next){
134         gatt_client_t * gatt_client = (gatt_client_t *) it;
135         if (gatt_client->con_handle == handle){
136             return gatt_client;
137         }
138     }
139     return NULL;
140 }
141 
142 
143 // @returns gatt_client context
144 // returns existing one, or tries to setup new one
145 static gatt_client_t * gatt_client_provide_context_for_handle(hci_con_handle_t con_handle){
146     gatt_client_t * gatt_client = gatt_client_get_context_for_handle(con_handle);
147     if (gatt_client) return gatt_client;
148 
149     // bail if no such hci connection
150     if (!hci_connection_for_handle(con_handle)){
151         log_error("No connection for handle 0x%04x", con_handle);
152         return NULL;
153     }
154     gatt_client = btstack_memory_gatt_client_get();
155     if (!gatt_client) return NULL;
156     // init state
157     gatt_client->con_handle = con_handle;
158     gatt_client->mtu = ATT_DEFAULT_MTU;
159     if (mtu_exchange_enabled){
160         gatt_client->mtu_state = SEND_MTU_EXCHANGE;
161     } else {
162         gatt_client->mtu_state = MTU_AUTO_EXCHANGE_DISABLED;
163     }
164     gatt_client->gatt_client_state = P_READY;
165     btstack_linked_list_add(&gatt_client_connections, (btstack_linked_item_t*)gatt_client);
166     return gatt_client;
167 }
168 
169 static gatt_client_t * gatt_client_provide_context_for_handle_and_start_timer(hci_con_handle_t con_handle){
170     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
171     if (gatt_client == NULL) return NULL;
172     gatt_client_timeout_start(gatt_client);
173     return gatt_client;
174 }
175 
176 static int is_ready(gatt_client_t * gatt_client){
177     return gatt_client->gatt_client_state == P_READY;
178 }
179 
180 int gatt_client_is_ready(hci_con_handle_t con_handle){
181     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
182     if (gatt_client == NULL) return 0;
183     return is_ready(gatt_client);
184 }
185 
186 void gatt_client_mtu_enable_auto_negotiation(uint8_t enabled){
187     mtu_exchange_enabled = enabled;
188 }
189 
190 uint8_t gatt_client_get_mtu(hci_con_handle_t con_handle, uint16_t * mtu){
191     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
192     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
193 
194     if ((gatt_client->mtu_state == MTU_EXCHANGED) || (gatt_client->mtu_state == MTU_AUTO_EXCHANGE_DISABLED)){
195         *mtu = gatt_client->mtu;
196         return ERROR_CODE_SUCCESS;
197     }
198     *mtu = ATT_DEFAULT_MTU;
199     return GATT_CLIENT_IN_WRONG_STATE;
200 }
201 
202 // precondition: can_send_packet_now == TRUE
203 static uint8_t att_confirmation(uint16_t con_handle){
204     l2cap_reserve_packet_buffer();
205     uint8_t * request = l2cap_get_outgoing_buffer();
206     request[0] = ATT_HANDLE_VALUE_CONFIRMATION;
207 
208     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 1);
209 }
210 
211 // precondition: can_send_packet_now == TRUE
212 static uint8_t att_find_information_request(uint16_t request_type, uint16_t con_handle, uint16_t start_handle, uint16_t end_handle){
213     l2cap_reserve_packet_buffer();
214     uint8_t * request = l2cap_get_outgoing_buffer();
215     request[0] = request_type;
216     little_endian_store_16(request, 1, start_handle);
217     little_endian_store_16(request, 3, end_handle);
218 
219     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 5);
220 }
221 
222 // precondition: can_send_packet_now == TRUE
223 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){
224     l2cap_reserve_packet_buffer();
225     uint8_t * request = l2cap_get_outgoing_buffer();
226 
227     request[0] = request_type;
228     little_endian_store_16(request, 1, start_handle);
229     little_endian_store_16(request, 3, end_handle);
230     little_endian_store_16(request, 5, attribute_group_type);
231     (void)memcpy(&request[7], value, value_size);
232 
233     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 7u + value_size);
234 }
235 
236 // precondition: can_send_packet_now == TRUE
237 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){
238     l2cap_reserve_packet_buffer();
239     uint8_t * request = l2cap_get_outgoing_buffer();
240     request[0] = request_type;
241     little_endian_store_16(request, 1, start_handle);
242     little_endian_store_16(request, 3, end_handle);
243     little_endian_store_16(request, 5, uuid16);
244 
245     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 7);
246 }
247 
248 // precondition: can_send_packet_now == TRUE
249 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){
250     l2cap_reserve_packet_buffer();
251     uint8_t * request = l2cap_get_outgoing_buffer();
252     request[0] = request_type;
253     little_endian_store_16(request, 1, start_handle);
254     little_endian_store_16(request, 3, end_handle);
255     reverse_128(uuid128, &request[5]);
256 
257     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 21);
258 }
259 
260 // precondition: can_send_packet_now == TRUE
261 static uint8_t att_read_request(uint16_t request_type, uint16_t con_handle, uint16_t attribute_handle){
262     l2cap_reserve_packet_buffer();
263     uint8_t * request = l2cap_get_outgoing_buffer();
264     request[0] = request_type;
265     little_endian_store_16(request, 1, attribute_handle);
266 
267     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 3);
268 }
269 
270 // precondition: can_send_packet_now == TRUE
271 static uint8_t att_read_blob_request(uint16_t request_type, uint16_t con_handle, uint16_t attribute_handle, uint16_t value_offset){
272     l2cap_reserve_packet_buffer();
273     uint8_t * request = l2cap_get_outgoing_buffer();
274     request[0] = request_type;
275     little_endian_store_16(request, 1, attribute_handle);
276     little_endian_store_16(request, 3, value_offset);
277 
278     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 5);
279 }
280 
281 static uint8_t att_read_multiple_request(uint16_t con_handle, uint16_t num_value_handles, uint16_t * value_handles){
282     l2cap_reserve_packet_buffer();
283     uint8_t * request = l2cap_get_outgoing_buffer();
284     request[0] = ATT_READ_MULTIPLE_REQUEST;
285     int i;
286     int offset = 1;
287     for (i=0;i<num_value_handles;i++){
288         little_endian_store_16(request, offset, value_handles[i]);
289         offset += 2;
290     }
291 
292     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, offset);
293 }
294 
295 #ifdef ENABLE_LE_SIGNED_WRITE
296 // precondition: can_send_packet_now == TRUE
297 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]){
298     l2cap_reserve_packet_buffer();
299     uint8_t * request = l2cap_get_outgoing_buffer();
300     request[0] = request_type;
301     little_endian_store_16(request, 1, attribute_handle);
302     (void)memcpy(&request[3], value, value_length);
303     little_endian_store_32(request, 3 + value_length, sign_counter);
304     reverse_64(sgn, &request[3 + value_length + 4]);
305 
306     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 3 + value_length + 12);
307 }
308 #endif
309 
310 // precondition: can_send_packet_now == TRUE
311 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){
312     l2cap_reserve_packet_buffer();
313     uint8_t * request = l2cap_get_outgoing_buffer();
314     request[0] = request_type;
315     little_endian_store_16(request, 1, attribute_handle);
316     (void)memcpy(&request[3], value, value_length);
317 
318     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 3u + value_length);
319 }
320 
321 // precondition: can_send_packet_now == TRUE
322 static uint8_t att_execute_write_request(uint16_t request_type, uint16_t con_handle, uint8_t execute_write){
323     l2cap_reserve_packet_buffer();
324     uint8_t * request = l2cap_get_outgoing_buffer();
325     request[0] = request_type;
326     request[1] = execute_write;
327 
328     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 2);
329 }
330 
331 // precondition: can_send_packet_now == TRUE
332 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){
333     l2cap_reserve_packet_buffer();
334     uint8_t * request = l2cap_get_outgoing_buffer();
335     request[0] = request_type;
336     little_endian_store_16(request, 1, attribute_handle);
337     little_endian_store_16(request, 3, value_offset);
338     (void)memcpy(&request[5], &value[value_offset], blob_length);
339 
340     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 5u + blob_length);
341 }
342 
343 static uint8_t att_exchange_mtu_request(uint16_t con_handle){
344     uint16_t mtu = l2cap_max_le_mtu();
345     l2cap_reserve_packet_buffer();
346     uint8_t * request = l2cap_get_outgoing_buffer();
347     request[0] = ATT_EXCHANGE_MTU_REQUEST;
348     little_endian_store_16(request, 1, mtu);
349 
350     return l2cap_send_prepared_connectionless(con_handle, L2CAP_CID_ATTRIBUTE_PROTOCOL, 3);
351 }
352 
353 static uint16_t write_blob_length(gatt_client_t * gatt_client){
354     uint16_t max_blob_length = gatt_client->mtu - 5u;
355     if (gatt_client->attribute_offset >= gatt_client->attribute_length) {
356         return 0;
357     }
358     uint16_t rest_length = gatt_client->attribute_length - gatt_client->attribute_offset;
359     if (max_blob_length > rest_length){
360         return rest_length;
361     }
362     return max_blob_length;
363 }
364 
365 static void send_gatt_services_request(gatt_client_t *gatt_client){
366     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);
367 }
368 
369 static void send_gatt_by_uuid_request(gatt_client_t *gatt_client, uint16_t attribute_group_type){
370     if (gatt_client->uuid16){
371         uint8_t uuid16[2];
372         little_endian_store_16(uuid16, 0, gatt_client->uuid16);
373         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);
374         return;
375     }
376     uint8_t uuid128[16];
377     reverse_128(gatt_client->uuid128, uuid128);
378     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);
379 }
380 
381 static void send_gatt_services_by_uuid_request(gatt_client_t *gatt_client){
382     send_gatt_by_uuid_request(gatt_client, GATT_PRIMARY_SERVICE_UUID);
383 }
384 
385 static void send_gatt_included_service_uuid_request(gatt_client_t *gatt_client){
386     att_read_request(ATT_READ_REQUEST, gatt_client->con_handle, gatt_client->query_start_handle);
387 }
388 
389 static void send_gatt_included_service_request(gatt_client_t *gatt_client){
390     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);
391 }
392 
393 static void send_gatt_characteristic_request(gatt_client_t *gatt_client){
394     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);
395 }
396 
397 static void send_gatt_characteristic_descriptor_request(gatt_client_t *gatt_client){
398     att_find_information_request(ATT_FIND_INFORMATION_REQUEST, gatt_client->con_handle, gatt_client->start_group_handle, gatt_client->end_group_handle);
399 }
400 
401 static void send_gatt_read_characteristic_value_request(gatt_client_t *gatt_client){
402     att_read_request(ATT_READ_REQUEST, gatt_client->con_handle, gatt_client->attribute_handle);
403 }
404 
405 static void send_gatt_read_by_type_request(gatt_client_t * gatt_client){
406     if (gatt_client->uuid16){
407         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);
408     } else {
409         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);
410     }
411 }
412 
413 static void send_gatt_read_blob_request(gatt_client_t *gatt_client){
414     att_read_blob_request(ATT_READ_BLOB_REQUEST, gatt_client->con_handle, gatt_client->attribute_handle, gatt_client->attribute_offset);
415 }
416 
417 static void send_gatt_read_multiple_request(gatt_client_t * gatt_client){
418     att_read_multiple_request(gatt_client->con_handle, gatt_client->read_multiple_handle_count, gatt_client->read_multiple_handles);
419 }
420 
421 static void send_gatt_write_attribute_value_request(gatt_client_t * gatt_client){
422     att_write_request(ATT_WRITE_REQUEST, gatt_client->con_handle, gatt_client->attribute_handle, gatt_client->attribute_length, gatt_client->attribute_value);
423 }
424 
425 static void send_gatt_write_client_characteristic_configuration_request(gatt_client_t * gatt_client){
426     att_write_request(ATT_WRITE_REQUEST, gatt_client->con_handle, gatt_client->client_characteristic_configuration_handle, 2, gatt_client->client_characteristic_configuration_value);
427 }
428 
429 static void send_gatt_prepare_write_request(gatt_client_t * gatt_client){
430     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);
431 }
432 
433 static void send_gatt_execute_write_request(gatt_client_t * gatt_client){
434     att_execute_write_request(ATT_EXECUTE_WRITE_REQUEST, gatt_client->con_handle, 1);
435 }
436 
437 static void send_gatt_cancel_prepared_write_request(gatt_client_t * gatt_client){
438     att_execute_write_request(ATT_EXECUTE_WRITE_REQUEST, gatt_client->con_handle, 0);
439 }
440 
441 #ifndef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
442 static void send_gatt_read_client_characteristic_configuration_request(gatt_client_t * gatt_client){
443     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);
444 }
445 #endif
446 
447 static void send_gatt_read_characteristic_descriptor_request(gatt_client_t * gatt_client){
448     att_read_request(ATT_READ_REQUEST, gatt_client->con_handle, gatt_client->attribute_handle);
449 }
450 
451 #ifdef ENABLE_LE_SIGNED_WRITE
452 static void send_gatt_signed_write_request(gatt_client_t * gatt_client, uint32_t sign_counter){
453     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);
454 }
455 #endif
456 
457 static uint16_t get_last_result_handle_from_service_list(uint8_t * packet, uint16_t size){
458     uint8_t attr_length = packet[1];
459     return little_endian_read_16(packet, size - attr_length + 2u);
460 }
461 
462 static uint16_t get_last_result_handle_from_characteristics_list(uint8_t * packet, uint16_t size){
463     uint8_t attr_length = packet[1];
464     return little_endian_read_16(packet, size - attr_length + 3u);
465 }
466 
467 static uint16_t get_last_result_handle_from_included_services_list(uint8_t * packet, uint16_t size){
468     uint8_t attr_length = packet[1];
469     return little_endian_read_16(packet, size - attr_length);
470 }
471 
472 static void gatt_client_handle_transaction_complete(gatt_client_t * gatt_client){
473     gatt_client->gatt_client_state = P_READY;
474     gatt_client_timeout_stop(gatt_client);
475 }
476 
477 static void emit_event_new(btstack_packet_handler_t callback, uint8_t * packet, uint16_t size){
478     if (!callback) return;
479     hci_dump_packet(HCI_EVENT_PACKET, 0, packet, size);
480     (*callback)(HCI_EVENT_PACKET, 0, packet, size);
481 }
482 
483 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){
484     notification->callback = packet_handler;
485     notification->con_handle = con_handle;
486     if (characteristic == NULL){
487         notification->attribute_handle = GATT_CLIENT_ANY_VALUE_HANDLE;
488     } else {
489         notification->attribute_handle = characteristic->value_handle;
490     }
491     btstack_linked_list_add(&gatt_client_value_listeners, (btstack_linked_item_t*) notification);
492 }
493 
494 void gatt_client_stop_listening_for_characteristic_value_updates(gatt_client_notification_t * notification){
495     btstack_linked_list_remove(&gatt_client_value_listeners, (btstack_linked_item_t*) notification);
496 }
497 
498 static void emit_event_to_registered_listeners(hci_con_handle_t con_handle, uint16_t attribute_handle, uint8_t * packet, uint16_t size){
499     btstack_linked_list_iterator_t it;
500     btstack_linked_list_iterator_init(&it, &gatt_client_value_listeners);
501     while (btstack_linked_list_iterator_has_next(&it)){
502         gatt_client_notification_t * notification = (gatt_client_notification_t*) btstack_linked_list_iterator_next(&it);
503         if ((notification->con_handle       != GATT_CLIENT_ANY_CONNECTION)   && (notification->con_handle       != con_handle)) continue;
504         if ((notification->attribute_handle != GATT_CLIENT_ANY_VALUE_HANDLE) && (notification->attribute_handle != attribute_handle)) continue;
505         (*notification->callback)(HCI_EVENT_PACKET, 0, packet, size);
506     }
507 }
508 
509 static void emit_gatt_complete_event(gatt_client_t * gatt_client, uint8_t att_status){
510     // @format H1
511     uint8_t packet[5];
512     packet[0] = GATT_EVENT_QUERY_COMPLETE;
513     packet[1] = 3;
514     little_endian_store_16(packet, 2, gatt_client->con_handle);
515     packet[4] = att_status;
516     emit_event_new(gatt_client->callback, packet, sizeof(packet));
517 }
518 
519 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){
520     // @format HX
521     uint8_t packet[24];
522     packet[0] = GATT_EVENT_SERVICE_QUERY_RESULT;
523     packet[1] = sizeof(packet) - 2u;
524     little_endian_store_16(packet, 2, gatt_client->con_handle);
525     ///
526     little_endian_store_16(packet, 4, start_group_handle);
527     little_endian_store_16(packet, 6, end_group_handle);
528     reverse_128(uuid128, &packet[8]);
529     emit_event_new(gatt_client->callback, packet, sizeof(packet));
530 }
531 
532 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){
533     // @format HX
534     uint8_t packet[26];
535     packet[0] = GATT_EVENT_INCLUDED_SERVICE_QUERY_RESULT;
536     packet[1] = sizeof(packet) - 2u;
537     little_endian_store_16(packet, 2, gatt_client->con_handle);
538     ///
539     little_endian_store_16(packet, 4, include_handle);
540     //
541     little_endian_store_16(packet, 6, start_group_handle);
542     little_endian_store_16(packet, 8, end_group_handle);
543     reverse_128(uuid128, &packet[10]);
544     emit_event_new(gatt_client->callback, packet, sizeof(packet));
545 }
546 
547 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,
548                                                         uint16_t properties, uint8_t * uuid128){
549     // @format HY
550     uint8_t packet[28];
551     packet[0] = GATT_EVENT_CHARACTERISTIC_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,  start_handle);
556     little_endian_store_16(packet, 6,  value_handle);
557     little_endian_store_16(packet, 8,  end_handle);
558     little_endian_store_16(packet, 10, properties);
559     reverse_128(uuid128, &packet[12]);
560     emit_event_new(gatt_client->callback, packet, sizeof(packet));
561 }
562 
563 static void emit_gatt_all_characteristic_descriptors_result_event(
564         gatt_client_t * gatt_client, uint16_t descriptor_handle, uint8_t * uuid128){
565     // @format HZ
566     uint8_t packet[22];
567     packet[0] = GATT_EVENT_ALL_CHARACTERISTIC_DESCRIPTORS_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,  descriptor_handle);
572     reverse_128(uuid128, &packet[6]);
573     emit_event_new(gatt_client->callback, packet, sizeof(packet));
574 }
575 
576 static void emit_gatt_mtu_exchanged_result_event(gatt_client_t * gatt_client, uint16_t new_mtu){
577     // @format H2
578     uint8_t packet[6];
579     packet[0] = GATT_EVENT_MTU;
580     packet[1] = sizeof(packet) - 2u;
581     little_endian_store_16(packet, 2, gatt_client->con_handle);
582     little_endian_store_16(packet, 4, new_mtu);
583     att_dispatch_client_mtu_exchanged(gatt_client->con_handle, new_mtu);
584     emit_event_new(gatt_client->callback, packet, sizeof(packet));
585 }
586 ///
587 static void report_gatt_services(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size){
588     uint8_t attr_length = packet[1];
589     uint8_t uuid_length = attr_length - 4u;
590 
591     int i;
592     for (i = 2; i < size; i += attr_length){
593         uint16_t start_group_handle = little_endian_read_16(packet,i);
594         uint16_t end_group_handle   = little_endian_read_16(packet,i+2);
595         uint8_t  uuid128[16];
596         uint16_t uuid16 = 0;
597 
598         if (uuid_length == 2u){
599             uuid16 = little_endian_read_16(packet, i+4);
600             uuid_add_bluetooth_prefix((uint8_t*) &uuid128, uuid16);
601         } else {
602             reverse_128(&packet[i+4], uuid128);
603         }
604         emit_gatt_service_query_result_event(gatt_client, start_group_handle, end_group_handle, uuid128);
605     }
606 }
607 
608 // helper
609 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){
610     uint8_t uuid128[16];
611     uint16_t uuid16 = 0;
612     if (uuid_length == 2u){
613         uuid16 = little_endian_read_16(uuid, 0);
614         uuid_add_bluetooth_prefix((uint8_t*) uuid128, uuid16);
615     } else if (uuid_length == 16u){
616         reverse_128(uuid, uuid128);
617     } else {
618         return;
619     }
620 
621     if (gatt_client->filter_with_uuid && (memcmp(gatt_client->uuid128, uuid128, 16) != 0)) return;
622 
623     gatt_client->characteristic_properties = properties;
624     gatt_client->characteristic_start_handle = start_handle;
625     gatt_client->attribute_handle = value_handle;
626 
627     if (gatt_client->filter_with_uuid) return;
628 
629     gatt_client->uuid16 = uuid16;
630     (void)memcpy(gatt_client->uuid128, uuid128, 16);
631 }
632 
633 static void characteristic_end_found(gatt_client_t * gatt_client, uint16_t end_handle){
634     // TODO: stop searching if filter and uuid found
635 
636     if (!gatt_client->characteristic_start_handle) return;
637 
638     emit_gatt_characteristic_query_result_event(gatt_client, gatt_client->characteristic_start_handle, gatt_client->attribute_handle,
639                                                 end_handle, gatt_client->characteristic_properties, gatt_client->uuid128);
640 
641     gatt_client->characteristic_start_handle = 0;
642 }
643 
644 static void report_gatt_characteristics(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size){
645     if (size < 2u) return;
646     uint8_t attr_length = packet[1];
647     if ((attr_length != 7u) && (attr_length != 21u)) return;
648     uint8_t uuid_length = attr_length - 5u;
649     int i;
650     for (i = 2u; (i + attr_length) <= size; i += attr_length){
651         uint16_t start_handle = little_endian_read_16(packet, i);
652         uint8_t  properties = packet[i+2];
653         uint16_t value_handle = little_endian_read_16(packet, i+3);
654         characteristic_end_found(gatt_client, start_handle - 1u);
655         characteristic_start_found(gatt_client, start_handle, properties, value_handle, &packet[i + 5], uuid_length);
656     }
657 }
658 
659 static void report_gatt_included_service_uuid16(gatt_client_t * gatt_client, uint16_t include_handle, uint16_t uuid16){
660     uint8_t normalized_uuid128[16];
661     uuid_add_bluetooth_prefix(normalized_uuid128, uuid16);
662     emit_gatt_included_service_query_result_event(gatt_client, include_handle, gatt_client->query_start_handle,
663                                                   gatt_client->query_end_handle, normalized_uuid128);
664 }
665 
666 static void report_gatt_included_service_uuid128(gatt_client_t * gatt_client, uint16_t include_handle, uint8_t *uuid128){
667     emit_gatt_included_service_query_result_event(gatt_client, include_handle, gatt_client->query_start_handle,
668                                                   gatt_client->query_end_handle, uuid128);
669 }
670 
671 // @returns packet pointer
672 // @note assume that value is part of an l2cap buffer - overwrite HCI + L2CAP packet headers
673 static const int characteristic_value_event_header_size = 8;
674 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){
675 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
676     // avoid using pre ATT headers.
677     return NULL;
678 #endif
679     // before the value inside the ATT PDU
680     uint8_t * packet = value - characteristic_value_event_header_size;
681     packet[0] = type;
682     packet[1] = characteristic_value_event_header_size - 2 + length;
683     little_endian_store_16(packet, 2, con_handle);
684     little_endian_store_16(packet, 4, attribute_handle);
685     little_endian_store_16(packet, 6, length);
686     return packet;
687 }
688 
689 // @returns packet pointer
690 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
691 static const int long_characteristic_value_event_header_size = 10;
692 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){
693 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
694     // avoid using pre ATT headers.
695     return NULL;
696 #endif
697 #if defined(HCI_INCOMING_PRE_BUFFER_SIZE) && (HCI_INCOMING_PRE_BUFFER_SIZE >= 10 - 8) // L2CAP Header (4) - ACL Header (4)
698     // before the value inside the ATT PDU
699     uint8_t * packet = value - long_characteristic_value_event_header_size;
700     packet[0] = type;
701     packet[1] = long_characteristic_value_event_header_size - 2 + length;
702     little_endian_store_16(packet, 2, con_handle);
703     little_endian_store_16(packet, 4, attribute_handle);
704     little_endian_store_16(packet, 6, offset);
705     little_endian_store_16(packet, 8, length);
706     return packet;
707 #else
708     log_error("HCI_INCOMING_PRE_BUFFER_SIZE >= 2 required for long characteristic reads");
709     return NULL;
710 #endif
711 }
712 
713 
714 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
715 static void report_gatt_notification(hci_con_handle_t con_handle, uint16_t value_handle, uint8_t * value, int length){
716     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_NOTIFICATION, con_handle, value_handle, value, length);
717     emit_event_to_registered_listeners(con_handle, value_handle, packet, characteristic_value_event_header_size + length);
718 }
719 
720 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
721 static void report_gatt_indication(hci_con_handle_t con_handle, uint16_t value_handle, uint8_t * value, int length){
722     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_INDICATION, con_handle, value_handle, value, length);
723     emit_event_to_registered_listeners(con_handle, value_handle, packet, characteristic_value_event_header_size + length);
724 }
725 
726 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
727 static void report_gatt_characteristic_value(gatt_client_t * gatt_client, uint16_t attribute_handle, uint8_t * value, uint16_t length){
728     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT, gatt_client->con_handle, attribute_handle, value, length);
729     emit_event_new(gatt_client->callback, packet, characteristic_value_event_header_size + length);
730 }
731 
732 // @note assume that value is part of an l2cap buffer - overwrite parts of the HCI/L2CAP/ATT packet (4/4/3) bytes
733 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){
734     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);
735     if (!packet) return;
736     emit_event_new(gatt_client->callback, packet, blob_length + long_characteristic_value_event_header_size);
737 }
738 
739 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){
740     UNUSED(value_offset);
741     uint8_t * packet = setup_characteristic_value_packet(GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT, gatt_client->con_handle, descriptor_handle, value, value_length);
742     emit_event_new(gatt_client->callback, packet, value_length + 8u);
743 }
744 
745 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){
746     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);
747     if (!packet) return;
748     emit_event_new(gatt_client->callback, packet, blob_length + long_characteristic_value_event_header_size);
749 }
750 
751 static void report_gatt_all_characteristic_descriptors(gatt_client_t * gatt_client, uint8_t * packet, uint16_t size, uint16_t pair_size){
752     int i;
753     for (i = 0u; (i + pair_size) <= size; i += pair_size){
754         uint16_t descriptor_handle = little_endian_read_16(packet,i);
755         uint8_t uuid128[16];
756         uint16_t uuid16 = 0;
757         if (pair_size == 4u){
758             uuid16 = little_endian_read_16(packet,i+2);
759             uuid_add_bluetooth_prefix(uuid128, uuid16);
760         } else {
761             reverse_128(&packet[i+2], uuid128);
762         }
763         emit_gatt_all_characteristic_descriptors_result_event(gatt_client, descriptor_handle, uuid128);
764     }
765 
766 }
767 
768 static int is_query_done(gatt_client_t * gatt_client, uint16_t last_result_handle){
769     return last_result_handle >= gatt_client->end_group_handle;
770 }
771 
772 static void trigger_next_query(gatt_client_t * gatt_client, uint16_t last_result_handle, gatt_client_state_t next_query_state){
773     if (is_query_done(gatt_client, last_result_handle)){
774         gatt_client_handle_transaction_complete(gatt_client);
775         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
776         return;
777     }
778     // next
779     gatt_client->start_group_handle = last_result_handle + 1u;
780     gatt_client->gatt_client_state = next_query_state;
781 }
782 
783 static void trigger_next_included_service_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
784     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_INCLUDED_SERVICE_QUERY);
785 }
786 
787 static void trigger_next_service_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
788     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_SERVICE_QUERY);
789 }
790 
791 static void trigger_next_service_by_uuid_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
792     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_SERVICE_WITH_UUID_QUERY);
793 }
794 
795 static void trigger_next_characteristic_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
796     if (is_query_done(gatt_client, last_result_handle)){
797         // report last characteristic
798         characteristic_end_found(gatt_client, gatt_client->end_group_handle);
799     }
800     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY);
801 }
802 
803 static void trigger_next_characteristic_descriptor_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
804     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY);
805 }
806 
807 static void trigger_next_read_by_type_query(gatt_client_t * gatt_client, uint16_t last_result_handle){
808     trigger_next_query(gatt_client, last_result_handle, P_W2_SEND_READ_BY_TYPE_REQUEST);
809 }
810 
811 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){
812     gatt_client->attribute_offset += write_blob_length(gatt_client);
813     uint16_t next_blob_length =  write_blob_length(gatt_client);
814 
815     if (next_blob_length == 0u){
816         gatt_client->gatt_client_state = done_state;
817         return;
818     }
819     gatt_client->gatt_client_state = next_query_state;
820 }
821 
822 static void trigger_next_blob_query(gatt_client_t * gatt_client, gatt_client_state_t next_query_state, uint16_t received_blob_length){
823 
824     uint16_t max_blob_length = gatt_client->mtu - 1u;
825     if (received_blob_length < max_blob_length){
826         gatt_client_handle_transaction_complete(gatt_client);
827         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
828         return;
829     }
830 
831     gatt_client->attribute_offset += received_blob_length;
832     gatt_client->gatt_client_state = next_query_state;
833 }
834 
835 
836 static int is_value_valid(gatt_client_t *gatt_client, uint8_t *packet, uint16_t size){
837     uint16_t attribute_handle = little_endian_read_16(packet, 1);
838     uint16_t value_offset = little_endian_read_16(packet, 3);
839 
840     if (gatt_client->attribute_handle != attribute_handle) return 0;
841     if (gatt_client->attribute_offset != value_offset) return 0;
842     return memcmp(&gatt_client->attribute_value[gatt_client->attribute_offset], &packet[5], size - 5u) == 0u;
843 }
844 
845 // returns 1 if packet was sent
846 static int gatt_client_run_for_gatt_client(gatt_client_t * gatt_client){
847 
848     // wait until re-encryption as central is complete
849     if (gap_reconnect_security_setup_active(gatt_client->con_handle)) return 0;
850 
851 #ifdef ENABLE_GATT_CLIENT_PAIRING
852     // wait until pairing complete
853     if (gatt_client->wait_for_pairing_complete) return 0;
854 #endif
855 
856     switch (gatt_client->mtu_state) {
857         case SEND_MTU_EXCHANGE:
858             gatt_client->mtu_state = SENT_MTU_EXCHANGE;
859             att_exchange_mtu_request(gatt_client->con_handle);
860             return 1;
861         case SENT_MTU_EXCHANGE:
862             return 0;
863         default:
864             break;
865     }
866 
867     if (gatt_client->send_confirmation){
868         gatt_client->send_confirmation = 0;
869         att_confirmation(gatt_client->con_handle);
870         return 1;
871     }
872 
873     // check MTU for writes
874     switch (gatt_client->gatt_client_state){
875         case P_W2_SEND_WRITE_CHARACTERISTIC_VALUE:
876         case P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR:
877             if (gatt_client->attribute_length <= (gatt_client->mtu - 3u)) break;
878             log_error("gatt_client_run: value len %u > MTU %u - 3\n", gatt_client->attribute_length,gatt_client->mtu);
879             gatt_client_handle_transaction_complete(gatt_client);
880             emit_gatt_complete_event(gatt_client, ATT_ERROR_INVALID_ATTRIBUTE_VALUE_LENGTH);
881             return 0;
882         default:
883             break;
884     }
885 
886     switch (gatt_client->gatt_client_state){
887         case P_W2_SEND_SERVICE_QUERY:
888             gatt_client->gatt_client_state = P_W4_SERVICE_QUERY_RESULT;
889             send_gatt_services_request(gatt_client);
890             return 1;
891 
892         case P_W2_SEND_SERVICE_WITH_UUID_QUERY:
893             gatt_client->gatt_client_state = P_W4_SERVICE_WITH_UUID_RESULT;
894             send_gatt_services_by_uuid_request(gatt_client);
895             return 1;
896 
897         case P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY:
898             gatt_client->gatt_client_state = P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT;
899             send_gatt_characteristic_request(gatt_client);
900             return 1;
901 
902         case P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY:
903             gatt_client->gatt_client_state = P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT;
904             send_gatt_characteristic_request(gatt_client);
905             return 1;
906 
907         case P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY:
908             gatt_client->gatt_client_state = P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT;
909             send_gatt_characteristic_descriptor_request(gatt_client);
910             return 1;
911 
912         case P_W2_SEND_INCLUDED_SERVICE_QUERY:
913             gatt_client->gatt_client_state = P_W4_INCLUDED_SERVICE_QUERY_RESULT;
914             send_gatt_included_service_request(gatt_client);
915             return 1;
916 
917         case P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY:
918             gatt_client->gatt_client_state = P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT;
919             send_gatt_included_service_uuid_request(gatt_client);
920             return 1;
921 
922         case P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY:
923             gatt_client->gatt_client_state = P_W4_READ_CHARACTERISTIC_VALUE_RESULT;
924             send_gatt_read_characteristic_value_request(gatt_client);
925             return 1;
926 
927         case P_W2_SEND_READ_BLOB_QUERY:
928             gatt_client->gatt_client_state = P_W4_READ_BLOB_RESULT;
929             send_gatt_read_blob_request(gatt_client);
930             return 1;
931 
932         case P_W2_SEND_READ_BY_TYPE_REQUEST:
933             gatt_client->gatt_client_state = P_W4_READ_BY_TYPE_RESPONSE;
934             send_gatt_read_by_type_request(gatt_client);
935             return 1;
936 
937         case P_W2_SEND_READ_MULTIPLE_REQUEST:
938             gatt_client->gatt_client_state = P_W4_READ_MULTIPLE_RESPONSE;
939             send_gatt_read_multiple_request(gatt_client);
940             return 1;
941 
942         case P_W2_SEND_WRITE_CHARACTERISTIC_VALUE:
943             gatt_client->gatt_client_state = P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT;
944             send_gatt_write_attribute_value_request(gatt_client);
945             return 1;
946 
947         case P_W2_PREPARE_WRITE:
948             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_RESULT;
949             send_gatt_prepare_write_request(gatt_client);
950             return 1;
951 
952         case P_W2_PREPARE_WRITE_SINGLE:
953             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_SINGLE_RESULT;
954             send_gatt_prepare_write_request(gatt_client);
955             return 1;
956 
957         case P_W2_PREPARE_RELIABLE_WRITE:
958             gatt_client->gatt_client_state = P_W4_PREPARE_RELIABLE_WRITE_RESULT;
959             send_gatt_prepare_write_request(gatt_client);
960             return 1;
961 
962         case P_W2_EXECUTE_PREPARED_WRITE:
963             gatt_client->gatt_client_state = P_W4_EXECUTE_PREPARED_WRITE_RESULT;
964             send_gatt_execute_write_request(gatt_client);
965             return 1;
966 
967         case P_W2_CANCEL_PREPARED_WRITE:
968             gatt_client->gatt_client_state = P_W4_CANCEL_PREPARED_WRITE_RESULT;
969             send_gatt_cancel_prepared_write_request(gatt_client);
970             return 1;
971 
972         case P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH:
973             gatt_client->gatt_client_state = P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT;
974             send_gatt_cancel_prepared_write_request(gatt_client);
975             return 1;
976 
977 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
978         case P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY:
979             // use Find Information
980             gatt_client->gatt_client_state = P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT;
981             send_gatt_characteristic_descriptor_request(gatt_client);
982 #else
983         case P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY:
984             // Use Read By Type
985             gatt_client->gatt_client_state = P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT;
986             send_gatt_read_client_characteristic_configuration_request(gatt_client);
987 #endif
988             return 1;
989 
990         case P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY:
991             gatt_client->gatt_client_state = P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT;
992             send_gatt_read_characteristic_descriptor_request(gatt_client);
993             return 1;
994 
995         case P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY:
996             gatt_client->gatt_client_state = P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT;
997             send_gatt_read_blob_request(gatt_client);
998             return 1;
999 
1000         case P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR:
1001             gatt_client->gatt_client_state = P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1002             send_gatt_write_attribute_value_request(gatt_client);
1003             return 1;
1004 
1005         case P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION:
1006             gatt_client->gatt_client_state = P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT;
1007             send_gatt_write_client_characteristic_configuration_request(gatt_client);
1008             return 1;
1009 
1010         case P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR:
1011             gatt_client->gatt_client_state = P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1012             send_gatt_prepare_write_request(gatt_client);
1013             return 1;
1014 
1015         case P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR:
1016             gatt_client->gatt_client_state = P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT;
1017             send_gatt_execute_write_request(gatt_client);
1018             return 1;
1019 
1020 #ifdef ENABLE_LE_SIGNED_WRITE
1021         case P_W4_IDENTITY_RESOLVING:
1022             log_info("P_W4_IDENTITY_RESOLVING - state %x", sm_identity_resolving_state(gatt_client->con_handle));
1023             switch (sm_identity_resolving_state(gatt_client->con_handle)){
1024                 case IRK_LOOKUP_SUCCEEDED:
1025                     gatt_client->le_device_index = sm_le_device_index(gatt_client->con_handle);
1026                     gatt_client->gatt_client_state = P_W4_CMAC_READY;
1027                     break;
1028                 case IRK_LOOKUP_FAILED:
1029                     gatt_client_handle_transaction_complete(gatt_client);
1030                     emit_gatt_complete_event(gatt_client, ATT_ERROR_BONDING_INFORMATION_MISSING);
1031                     return 0;
1032                 default:
1033                     return 0;
1034             }
1035 
1036             /* Fall through */
1037 
1038         case P_W4_CMAC_READY:
1039             if (sm_cmac_ready()){
1040                 sm_key_t csrk;
1041                 le_device_db_local_csrk_get(gatt_client->le_device_index, csrk);
1042                 uint32_t sign_counter = le_device_db_local_counter_get(gatt_client->le_device_index);
1043                 gatt_client->gatt_client_state = P_W4_CMAC_RESULT;
1044                 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);
1045             }
1046             return 0;
1047 
1048         case P_W2_SEND_SIGNED_WRITE: {
1049             gatt_client->gatt_client_state = P_W4_SEND_SINGED_WRITE_DONE;
1050             // bump local signing counter
1051             uint32_t sign_counter = le_device_db_local_counter_get(gatt_client->le_device_index);
1052             le_device_db_local_counter_set(gatt_client->le_device_index, sign_counter + 1);
1053             // send signed write command
1054             send_gatt_signed_write_request(gatt_client, sign_counter);
1055             // finally, notifiy client that write is complete
1056             gatt_client_handle_transaction_complete(gatt_client);
1057             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1058             return 1;
1059         }
1060 #endif
1061         default:
1062             break;
1063     }
1064 
1065     // requested can send snow?
1066     if (gatt_client->write_without_response_callback){
1067         btstack_packet_handler_t packet_handler = gatt_client->write_without_response_callback;
1068         gatt_client->write_without_response_callback = NULL;
1069         uint8_t event[4];
1070         event[0] = GATT_EVENT_CAN_WRITE_WITHOUT_RESPONSE;
1071         event[1] = sizeof(event) - 2u;
1072         little_endian_store_16(event, 2, gatt_client->con_handle);
1073         packet_handler(HCI_EVENT_PACKET, gatt_client->con_handle, event, sizeof(event));
1074         return 1; // to trigger requeueing (even if higher layer didn't sent)
1075     }
1076 
1077     return 0;
1078 }
1079 
1080 static void gatt_client_run(void){
1081     btstack_linked_item_t *it;
1082     for (it = (btstack_linked_item_t *) gatt_client_connections; it != NULL; it = it->next){
1083         gatt_client_t * gatt_client = (gatt_client_t *) it;
1084         if (!att_dispatch_client_can_send_now(gatt_client->con_handle)) {
1085             att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
1086             return;
1087         }
1088         int packet_sent = gatt_client_run_for_gatt_client(gatt_client);
1089         if (packet_sent){
1090             // request new permission
1091             att_dispatch_client_request_can_send_now_event(gatt_client->con_handle);
1092             // requeue client for fairness and exit
1093             // note: iterator has become invalid
1094             btstack_linked_list_remove(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1095             btstack_linked_list_add_tail(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1096             return;
1097         }
1098     }
1099 }
1100 
1101 static void gatt_client_report_error_if_pending(gatt_client_t *gatt_client, uint8_t att_error_code) {
1102     if (is_ready(gatt_client) == 1) return;
1103     gatt_client_handle_transaction_complete(gatt_client);
1104     emit_gatt_complete_event(gatt_client, att_error_code);
1105 }
1106 
1107 static void gatt_client_event_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1108     UNUSED(channel);    // ok: handling own l2cap events
1109     UNUSED(size);       // ok: there is no channel
1110 
1111     if (packet_type != HCI_EVENT_PACKET) return;
1112 
1113     hci_con_handle_t con_handle;
1114     gatt_client_t * gatt_client;
1115     switch (hci_event_packet_get_type(packet)) {
1116         case HCI_EVENT_DISCONNECTION_COMPLETE:
1117             log_info("GATT Client: HCI_EVENT_DISCONNECTION_COMPLETE");
1118             con_handle = little_endian_read_16(packet,3);
1119             gatt_client = gatt_client_get_context_for_handle(con_handle);
1120             if (gatt_client == NULL) break;
1121 
1122             gatt_client_report_error_if_pending(gatt_client, ATT_ERROR_HCI_DISCONNECT_RECEIVED);
1123             gatt_client_timeout_stop(gatt_client);
1124             btstack_linked_list_remove(&gatt_client_connections, (btstack_linked_item_t *) gatt_client);
1125             btstack_memory_gatt_client_free(gatt_client);
1126             break;
1127 
1128 #ifdef ENABLE_GATT_CLIENT_PAIRING
1129         // Pairing complete (with/without bonding=storing of pairing information)
1130         case SM_EVENT_PAIRING_COMPLETE:
1131             con_handle = sm_event_pairing_complete_get_handle(packet);
1132             gatt_client = gatt_client_get_context_for_handle(con_handle);
1133             if (gatt_client == NULL) break;
1134 
1135             if (gatt_client->wait_for_pairing_complete){
1136                 gatt_client->wait_for_pairing_complete = 0;
1137                 if (sm_event_pairing_complete_get_status(packet)){
1138                     log_info("pairing failed, report previous error 0x%x", gatt_client->pending_error_code);
1139                     gatt_client_handle_transaction_complete(gatt_client);
1140                     emit_gatt_complete_event(gatt_client, gatt_client->pending_error_code);
1141                 } else {
1142                     log_info("pairing success, retry operation");
1143                 }
1144             }
1145             break;
1146 #endif
1147 #ifdef ENABLE_LE_SIGNED_WRITE
1148         // Identity Resolving completed (no code, gatt_client_run will continue)
1149         case SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED:
1150         case SM_EVENT_IDENTITY_RESOLVING_FAILED:
1151             break;
1152 #endif
1153 
1154         default:
1155             break;
1156     }
1157 
1158     gatt_client_run();
1159 }
1160 
1161 static void gatt_client_att_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
1162     gatt_client_t * gatt_client;
1163     if (size < 1u) return;
1164 
1165     if (packet_type == HCI_EVENT_PACKET) {
1166         switch (packet[0]){
1167             case L2CAP_EVENT_CAN_SEND_NOW:
1168                 gatt_client_run();
1169                 break;
1170             // att_server has negotiated the mtu for this connection, cache if context exists
1171             case ATT_EVENT_MTU_EXCHANGE_COMPLETE:
1172                 if (size < 6u) break;
1173                 gatt_client = gatt_client_get_context_for_handle(handle);
1174                 if (gatt_client == NULL) break;
1175                 gatt_client->mtu = little_endian_read_16(packet, 4);
1176                 break;
1177             default:
1178                 break;
1179         }
1180         return;
1181     }
1182 
1183     if (packet_type != ATT_DATA_PACKET) return;
1184 
1185     // special cases: notifications don't need a context while indications motivate creating one
1186     switch (packet[0]){
1187         case ATT_HANDLE_VALUE_NOTIFICATION:
1188             if (size < 3u) return;
1189             report_gatt_notification(handle, little_endian_read_16(packet,1u), &packet[3], size-3u);
1190             return;
1191         case ATT_HANDLE_VALUE_INDICATION:
1192             gatt_client = gatt_client_provide_context_for_handle(handle);
1193             break;
1194         default:
1195             gatt_client = gatt_client_get_context_for_handle(handle);
1196             break;
1197     }
1198 
1199     if (gatt_client == NULL) return;
1200 
1201     switch (packet[0]){
1202         case ATT_EXCHANGE_MTU_RESPONSE:
1203         {
1204             if (size < 3u) break;
1205             uint16_t remote_rx_mtu = little_endian_read_16(packet, 1);
1206             uint16_t local_rx_mtu = l2cap_max_le_mtu();
1207             gatt_client->mtu = (remote_rx_mtu < local_rx_mtu) ? remote_rx_mtu : local_rx_mtu;
1208             gatt_client->mtu_state = MTU_EXCHANGED;
1209             emit_gatt_mtu_exchanged_result_event(gatt_client, gatt_client->mtu);
1210             break;
1211         }
1212         case ATT_READ_BY_GROUP_TYPE_RESPONSE:
1213             switch(gatt_client->gatt_client_state){
1214                 case P_W4_SERVICE_QUERY_RESULT:
1215                     report_gatt_services(gatt_client, packet, size);
1216                     trigger_next_service_query(gatt_client, get_last_result_handle_from_service_list(packet, size));
1217                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1218                     break;
1219                 default:
1220                     break;
1221             }
1222             break;
1223         case ATT_HANDLE_VALUE_INDICATION:
1224             if (size < 3u) break;
1225             report_gatt_indication(handle, little_endian_read_16(packet,1u), &packet[3], size-3u);
1226             gatt_client->send_confirmation = 1;
1227             break;
1228 
1229         case ATT_READ_BY_TYPE_RESPONSE:
1230             switch (gatt_client->gatt_client_state){
1231                 case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1232                     report_gatt_characteristics(gatt_client, packet, size);
1233                     trigger_next_characteristic_query(gatt_client, get_last_result_handle_from_characteristics_list(packet, size));
1234                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1235                     break;
1236                 case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1237                     report_gatt_characteristics(gatt_client, packet, size);
1238                     trigger_next_characteristic_query(gatt_client, get_last_result_handle_from_characteristics_list(packet, size));
1239                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1240                     break;
1241                 case P_W4_INCLUDED_SERVICE_QUERY_RESULT:
1242                 {
1243                     if (size < 2u) break;
1244                     uint16_t uuid16 = 0;
1245                     uint16_t pair_size = packet[1];
1246 
1247                     if (pair_size == 6u){
1248                         if (size < 8u) break;
1249                         // UUIDs not available, query first included service
1250                         gatt_client->start_group_handle = little_endian_read_16(packet, 2); // ready for next query
1251                         gatt_client->query_start_handle = little_endian_read_16(packet, 4);
1252                         gatt_client->query_end_handle = little_endian_read_16(packet, 6);
1253                         gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY;
1254                         break;
1255                     }
1256 
1257                     if (pair_size != 8u) break;
1258 
1259                     // UUIDs included, report all of them
1260                     uint16_t offset;
1261                     for (offset = 2u; (offset + 8u) <= size; offset += pair_size){
1262                         uint16_t include_handle = little_endian_read_16(packet, offset);
1263                         gatt_client->query_start_handle = little_endian_read_16(packet, offset + 2u);
1264                         gatt_client->query_end_handle = little_endian_read_16(packet, offset + 4u);
1265                         uuid16 = little_endian_read_16(packet, offset+6u);
1266                         report_gatt_included_service_uuid16(gatt_client, include_handle, uuid16);
1267                     }
1268 
1269                     trigger_next_included_service_query(gatt_client, get_last_result_handle_from_included_services_list(packet, size));
1270                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1271                     break;
1272                 }
1273 #ifndef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1274                 case P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT:
1275                     gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, 2);
1276                     gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1277                     break;
1278 #endif
1279                 case P_W4_READ_BY_TYPE_RESPONSE: {
1280                     uint16_t pair_size = packet[1];
1281                     uint16_t offset;
1282                     uint16_t last_result_handle = 0;
1283                     for (offset = 2; offset < size ; offset += pair_size){
1284                         uint16_t value_handle = little_endian_read_16(packet, offset);
1285                         report_gatt_characteristic_value(gatt_client, value_handle, &packet[offset + 2u], pair_size - 2u);
1286                         last_result_handle = value_handle;
1287                     }
1288                     trigger_next_read_by_type_query(gatt_client, last_result_handle);
1289                     break;
1290                 }
1291                 default:
1292                     break;
1293             }
1294             break;
1295         case ATT_READ_RESPONSE:
1296             switch (gatt_client->gatt_client_state){
1297                 case P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT: {
1298                     uint8_t uuid128[16];
1299                     reverse_128(&packet[1], uuid128);
1300                     report_gatt_included_service_uuid128(gatt_client, gatt_client->start_group_handle, uuid128);
1301                     trigger_next_included_service_query(gatt_client, gatt_client->start_group_handle);
1302                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1303                     break;
1304                 }
1305                 case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1306                     gatt_client_handle_transaction_complete(gatt_client);
1307                     report_gatt_characteristic_value(gatt_client, gatt_client->attribute_handle, &packet[1], size - 1u);
1308                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1309                     break;
1310 
1311                 case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:{
1312                     gatt_client_handle_transaction_complete(gatt_client);
1313                     report_gatt_characteristic_descriptor(gatt_client, gatt_client->attribute_handle, &packet[1], size - 1u, 0u);
1314                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1315                     break;
1316                 }
1317                 default:
1318                     break;
1319             }
1320             break;
1321 
1322         case ATT_FIND_BY_TYPE_VALUE_RESPONSE:
1323         {
1324             uint8_t pair_size = 4;
1325             int i;
1326             uint16_t start_group_handle;
1327             uint16_t   end_group_handle= 0xffff; // asserts GATT_EVENT_QUERY_COMPLETE is emitted if no results
1328             for (i = 1u; (i + pair_size) <= size; i += pair_size){
1329                 start_group_handle = little_endian_read_16(packet,i);
1330                 end_group_handle = little_endian_read_16(packet,i+2);
1331                 emit_gatt_service_query_result_event(gatt_client, start_group_handle, end_group_handle, gatt_client->uuid128);
1332             }
1333             trigger_next_service_by_uuid_query(gatt_client, end_group_handle);
1334             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1335             break;
1336         }
1337         case ATT_FIND_INFORMATION_REPLY:
1338         {
1339             if (size < 2u) break;
1340 
1341             uint8_t pair_size = 4;
1342             if (packet[1u] == 2u){
1343                 pair_size = 18;
1344             }
1345             uint16_t offset = 2;
1346 
1347             if (size < (pair_size + offset)) break;
1348             uint16_t last_descriptor_handle = little_endian_read_16(packet, size - pair_size);
1349 
1350 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1351             log_info("ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY, state %x", gatt_client->gatt_client_state);
1352             if (gatt_client->gatt_client_state == P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT){
1353                 // iterate over descriptors looking for CCC
1354                 if (pair_size == 4){
1355                     while ((offset + 4) <= size){
1356                         uint16_t uuid16 = little_endian_read_16(packet, offset + 2);
1357                         if (uuid16 == GATT_CLIENT_CHARACTERISTICS_CONFIGURATION){
1358                             gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, offset);
1359                             gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1360                             log_info("CCC found %x", gatt_client->client_characteristic_configuration_handle);
1361                             break;
1362                         }
1363                         offset += pair_size;
1364                     }
1365                 }
1366                 if (is_query_done(gatt_client, last_descriptor_handle)){
1367 
1368                 } else {
1369                     // next
1370                     gatt_client->start_group_handle = last_descriptor_handle + 1;
1371                     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
1372                 }
1373                 break;
1374             }
1375 #endif
1376             report_gatt_all_characteristic_descriptors(gatt_client, &packet[2], size - 2u, pair_size);
1377             trigger_next_characteristic_descriptor_query(gatt_client, last_descriptor_handle);
1378             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1379             break;
1380         }
1381 
1382         case ATT_WRITE_RESPONSE:
1383             switch (gatt_client->gatt_client_state){
1384                 case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1385                     gatt_client_handle_transaction_complete(gatt_client);
1386                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1387                     break;
1388                 case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1389                     gatt_client_handle_transaction_complete(gatt_client);
1390                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1391                     break;
1392                 case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1393                     gatt_client_handle_transaction_complete(gatt_client);
1394                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1395                     break;
1396                 default:
1397                     break;
1398             }
1399             break;
1400 
1401         case ATT_READ_BLOB_RESPONSE:{
1402             uint16_t received_blob_length = size-1u;
1403             switch(gatt_client->gatt_client_state){
1404                 case P_W4_READ_BLOB_RESULT:
1405                     report_gatt_long_characteristic_value_blob(gatt_client, gatt_client->attribute_handle, &packet[1], received_blob_length, gatt_client->attribute_offset);
1406                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_QUERY, received_blob_length);
1407                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1408                     break;
1409                 case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1410                     report_gatt_long_characteristic_descriptor(gatt_client, gatt_client->attribute_handle,
1411                                                                &packet[1], received_blob_length,
1412                                                                gatt_client->attribute_offset);
1413                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY, received_blob_length);
1414                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1415                     break;
1416                 default:
1417                     break;
1418             }
1419             break;
1420         }
1421         case ATT_PREPARE_WRITE_RESPONSE:
1422             switch (gatt_client->gatt_client_state){
1423                 case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1424                     gatt_client_handle_transaction_complete(gatt_client);
1425                     if (is_value_valid(gatt_client, packet, size)){
1426                         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1427                     } else {
1428                         emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1429                     }
1430                     break;
1431 
1432                 case P_W4_PREPARE_WRITE_RESULT:{
1433                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1434                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE, P_W2_EXECUTE_PREPARED_WRITE);
1435                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1436                     break;
1437                 }
1438                 case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:{
1439                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1440                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR, P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR);
1441                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1442                     break;
1443                 }
1444                 case P_W4_PREPARE_RELIABLE_WRITE_RESULT:{
1445                     if (is_value_valid(gatt_client, packet, size)){
1446                         gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1447                         trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_RELIABLE_WRITE, P_W2_EXECUTE_PREPARED_WRITE);
1448                         // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1449                         break;
1450                     }
1451                     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1452                     break;
1453                 }
1454                 default:
1455                     break;
1456             }
1457             break;
1458 
1459         case ATT_EXECUTE_WRITE_RESPONSE:
1460             switch (gatt_client->gatt_client_state){
1461                 case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1462                     gatt_client_handle_transaction_complete(gatt_client);
1463                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1464                     break;
1465                 case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1466                     gatt_client_handle_transaction_complete(gatt_client);
1467                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1468                     break;
1469                 case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1470                     gatt_client_handle_transaction_complete(gatt_client);
1471                     emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1472                     break;
1473                 case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1474                     gatt_client_handle_transaction_complete(gatt_client);
1475                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1476                     break;
1477                 default:
1478                     break;
1479 
1480             }
1481             break;
1482 
1483         case ATT_READ_MULTIPLE_RESPONSE:
1484             switch(gatt_client->gatt_client_state){
1485                 case P_W4_READ_MULTIPLE_RESPONSE:
1486                     report_gatt_characteristic_value(gatt_client, 0u, &packet[1], size - 1u);
1487                     gatt_client_handle_transaction_complete(gatt_client);
1488                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1489                     break;
1490                 default:
1491                     break;
1492             }
1493             break;
1494 
1495         case ATT_ERROR_RESPONSE:
1496             if (size < 5u) return;
1497             switch (packet[4]){
1498                 case ATT_ERROR_ATTRIBUTE_NOT_FOUND: {
1499                     switch(gatt_client->gatt_client_state){
1500                         case P_W4_SERVICE_QUERY_RESULT:
1501                         case P_W4_SERVICE_WITH_UUID_RESULT:
1502                         case P_W4_INCLUDED_SERVICE_QUERY_RESULT:
1503                         case P_W4_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT:
1504                             gatt_client_handle_transaction_complete(gatt_client);
1505                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1506                             break;
1507                         case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1508                         case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1509                             characteristic_end_found(gatt_client, gatt_client->end_group_handle);
1510                             gatt_client_handle_transaction_complete(gatt_client);
1511                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1512                             break;
1513                         case P_W4_READ_BY_TYPE_RESPONSE:
1514                             gatt_client_handle_transaction_complete(gatt_client);
1515                             if (gatt_client->start_group_handle == gatt_client->query_start_handle){
1516                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_ATTRIBUTE_NOT_FOUND);
1517                             } else {
1518                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1519                             }
1520                             break;
1521                         default:
1522                             gatt_client_report_error_if_pending(gatt_client, packet[4]);
1523                             break;
1524                     }
1525                     break;
1526                 }
1527 
1528 #ifdef ENABLE_GATT_CLIENT_PAIRING
1529 
1530                 case ATT_ERROR_INSUFFICIENT_AUTHENTICATION:
1531                 case ATT_ERROR_INSUFFICIENT_ENCRYPTION_KEY_SIZE:
1532                 case ATT_ERROR_INSUFFICIENT_ENCRYPTION: {
1533 
1534                     // security too low
1535                     if (gatt_client->security_counter > 0) {
1536                         gatt_client_report_error_if_pending(gatt_client, packet[4]);
1537                         break;
1538                     }
1539                     // start security
1540                     gatt_client->security_counter++;
1541 
1542                     // setup action
1543                     int retry = 1;
1544                     switch (gatt_client->gatt_client_state){
1545                         case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1546                             gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY ;
1547                             break;
1548                         case P_W4_READ_BLOB_RESULT:
1549                             gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
1550                             break;
1551                         case P_W4_READ_BY_TYPE_RESPONSE:
1552                             gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1553                             break;
1554                         case P_W4_READ_MULTIPLE_RESPONSE:
1555                             gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
1556                             break;
1557                         case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1558                             gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
1559                             break;
1560                         case P_W4_PREPARE_WRITE_RESULT:
1561                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
1562                             break;
1563                         case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1564                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
1565                             break;
1566                         case P_W4_PREPARE_RELIABLE_WRITE_RESULT:
1567                             gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
1568                             break;
1569                         case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1570                             gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
1571                             break;
1572                         case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1573                             gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
1574                             break;
1575                         case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1576                             gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1577                             break;
1578                         case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:
1579                             gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
1580                             break;
1581                         case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1582                             gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
1583                             break;
1584                         case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1585                             gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
1586                             break;
1587                         case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1588                             gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1589                             break;
1590                         case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1591                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
1592                             break;
1593                         case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1594                             gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR;
1595                             break;
1596 #ifdef ENABLE_LE_SIGNED_WRITE
1597                         case P_W4_SEND_SINGED_WRITE_DONE:
1598                             gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1599                             break;
1600 #endif
1601                         default:
1602                             log_info("retry not supported for state %x", gatt_client->gatt_client_state);
1603                             retry = 0;
1604                             break;
1605                     }
1606 
1607                     if (!retry) {
1608                         gatt_client_report_error_if_pending(gatt_client, packet[4]);
1609                         break;
1610                     }
1611 
1612                     log_info("security error, start pairing");
1613 
1614                     // requrest pairing
1615                     gatt_client->wait_for_pairing_complete = 1;
1616                     gatt_client->pending_error_code = packet[4];
1617                     sm_request_pairing(gatt_client->con_handle);
1618                     break;
1619                 }
1620 #endif
1621 
1622                 // nothing we can do about that
1623                 case ATT_ERROR_INSUFFICIENT_AUTHORIZATION:
1624                 default:
1625                     gatt_client_report_error_if_pending(gatt_client, packet[4]);
1626                     break;
1627             }
1628             break;
1629 
1630         default:
1631             log_info("ATT Handler, unhandled response type 0x%02x", packet[0]);
1632             break;
1633     }
1634     gatt_client_run();
1635 }
1636 
1637 #ifdef ENABLE_LE_SIGNED_WRITE
1638 static void att_signed_write_handle_cmac_result(uint8_t hash[8]){
1639     btstack_linked_list_iterator_t it;
1640     btstack_linked_list_iterator_init(&it, &gatt_client_connections);
1641     while (btstack_linked_list_iterator_has_next(&it)){
1642         gatt_client_t * gatt_client = (gatt_client_t *) btstack_linked_list_iterator_next(&it);
1643         if (gatt_client->gatt_client_state == P_W4_CMAC_RESULT){
1644             // store result
1645             (void)memcpy(gatt_client->cmac, hash, 8);
1646             // reverse_64(hash, gatt_client->cmac);
1647             gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1648             gatt_client_run();
1649             return;
1650         }
1651     }
1652 }
1653 
1654 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){
1655     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
1656     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1657     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1658 
1659     gatt_client->callback = callback;
1660     gatt_client->attribute_handle = handle;
1661     gatt_client->attribute_length = message_len;
1662     gatt_client->attribute_value = message;
1663     gatt_client->gatt_client_state = P_W4_IDENTITY_RESOLVING;
1664     gatt_client_run();
1665     return ERROR_CODE_SUCCESS;
1666 }
1667 #endif
1668 
1669 uint8_t gatt_client_discover_primary_services(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
1670     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1671     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1672     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1673 
1674     gatt_client->callback = callback;
1675     gatt_client->start_group_handle = 0x0001;
1676     gatt_client->end_group_handle   = 0xffff;
1677     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_QUERY;
1678     gatt_client->uuid16 = 0;
1679     gatt_client_run();
1680     return ERROR_CODE_SUCCESS;
1681 }
1682 
1683 
1684 uint8_t gatt_client_discover_primary_services_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t uuid16){
1685     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1686     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1687     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1688 
1689     gatt_client->callback = callback;
1690     gatt_client->start_group_handle = 0x0001;
1691     gatt_client->end_group_handle   = 0xffff;
1692     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
1693     gatt_client->uuid16 = uuid16;
1694     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), gatt_client->uuid16);
1695     gatt_client_run();
1696     return ERROR_CODE_SUCCESS;
1697 }
1698 
1699 uint8_t gatt_client_discover_primary_services_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, const uint8_t * uuid128){
1700     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1701     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1702     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1703 
1704     gatt_client->callback = callback;
1705     gatt_client->start_group_handle = 0x0001;
1706     gatt_client->end_group_handle   = 0xffff;
1707     gatt_client->uuid16 = 0;
1708     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1709     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
1710     gatt_client_run();
1711     return ERROR_CODE_SUCCESS;
1712 }
1713 
1714 uint8_t gatt_client_discover_characteristics_for_service(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t *service){
1715     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1716     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1717     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1718 
1719     gatt_client->callback = callback;
1720     gatt_client->start_group_handle = service->start_group_handle;
1721     gatt_client->end_group_handle   = service->end_group_handle;
1722     gatt_client->filter_with_uuid = 0;
1723     gatt_client->characteristic_start_handle = 0;
1724     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY;
1725     gatt_client_run();
1726     return ERROR_CODE_SUCCESS;
1727 }
1728 
1729 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){
1730     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1731     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1732     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1733     gatt_client->callback = callback;
1734     gatt_client->start_group_handle = service->start_group_handle;
1735     gatt_client->end_group_handle   = service->end_group_handle;
1736     gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_QUERY;
1737 
1738     gatt_client_run();
1739     return ERROR_CODE_SUCCESS;
1740 }
1741 
1742 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){
1743     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1744     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1745     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1746 
1747     gatt_client->callback = callback;
1748     gatt_client->start_group_handle = start_handle;
1749     gatt_client->end_group_handle   = end_handle;
1750     gatt_client->filter_with_uuid = 1;
1751     gatt_client->uuid16 = uuid16;
1752     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
1753     gatt_client->characteristic_start_handle = 0;
1754     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
1755     gatt_client_run();
1756     return ERROR_CODE_SUCCESS;
1757 }
1758 
1759 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){
1760     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1761     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1762     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1763 
1764     gatt_client->callback = callback;
1765     gatt_client->start_group_handle = start_handle;
1766     gatt_client->end_group_handle   = end_handle;
1767     gatt_client->filter_with_uuid = 1;
1768     gatt_client->uuid16 = 0;
1769     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1770     gatt_client->characteristic_start_handle = 0;
1771     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
1772     gatt_client_run();
1773     return ERROR_CODE_SUCCESS;
1774 }
1775 
1776 
1777 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){
1778     return gatt_client_discover_characteristics_for_handle_range_by_uuid16(callback, handle, service->start_group_handle, service->end_group_handle, uuid16);
1779 }
1780 
1781 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){
1782     return gatt_client_discover_characteristics_for_handle_range_by_uuid128(callback, handle, service->start_group_handle, service->end_group_handle, uuid128);
1783 }
1784 
1785 uint8_t gatt_client_discover_characteristic_descriptors(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t *characteristic){
1786     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1787     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1788     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1789 
1790     if (characteristic->value_handle == characteristic->end_handle){
1791         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1792         return ERROR_CODE_SUCCESS;
1793     }
1794     gatt_client->callback = callback;
1795     gatt_client->start_group_handle = characteristic->value_handle + 1u;
1796     gatt_client->end_group_handle   = characteristic->end_handle;
1797     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY;
1798     gatt_client_run();
1799     return ERROR_CODE_SUCCESS;
1800 }
1801 
1802 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){
1803     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1804     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1805     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1806 
1807     gatt_client->callback = callback;
1808     gatt_client->attribute_handle = value_handle;
1809     gatt_client->attribute_offset = 0;
1810     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY;
1811     gatt_client_run();
1812     return ERROR_CODE_SUCCESS;
1813 }
1814 
1815 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){
1816     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1817     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1818     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1819 
1820     gatt_client->callback = callback;
1821     gatt_client->start_group_handle = start_handle;
1822     gatt_client->end_group_handle = end_handle;
1823     gatt_client->query_start_handle = start_handle;
1824     gatt_client->query_end_handle = end_handle;
1825     gatt_client->uuid16 = uuid16;
1826     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
1827     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1828     gatt_client_run();
1829     return ERROR_CODE_SUCCESS;
1830 }
1831 
1832 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){
1833     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1834     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1835     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1836 
1837     gatt_client->callback = callback;
1838     gatt_client->start_group_handle = start_handle;
1839     gatt_client->end_group_handle = end_handle;
1840     gatt_client->query_start_handle = start_handle;
1841     gatt_client->query_end_handle = end_handle;
1842     gatt_client->uuid16 = 0;
1843     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1844     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1845     gatt_client_run();
1846     return ERROR_CODE_SUCCESS;
1847 }
1848 
1849 
1850 uint8_t gatt_client_read_value_of_characteristic(btstack_packet_handler_t callback, uint16_t handle, gatt_client_characteristic_t *characteristic){
1851     return gatt_client_read_value_of_characteristic_using_value_handle(callback, handle, characteristic->value_handle);
1852 }
1853 
1854 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){
1855     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1856     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1857     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1858 
1859     gatt_client->callback = callback;
1860     gatt_client->attribute_handle = characteristic_value_handle;
1861     gatt_client->attribute_offset = offset;
1862     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
1863     gatt_client_run();
1864     return ERROR_CODE_SUCCESS;
1865 }
1866 
1867 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){
1868     return gatt_client_read_long_value_of_characteristic_using_value_handle_with_offset(callback, con_handle, characteristic_value_handle, 0);
1869 }
1870 
1871 uint8_t gatt_client_read_long_value_of_characteristic(btstack_packet_handler_t callback, uint16_t handle, gatt_client_characteristic_t *characteristic){
1872     return gatt_client_read_long_value_of_characteristic_using_value_handle(callback, handle, characteristic->value_handle);
1873 }
1874 
1875 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){
1876     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1877     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1878     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1879 
1880     gatt_client->callback = callback;
1881     gatt_client->read_multiple_handle_count = num_value_handles;
1882     gatt_client->read_multiple_handles = value_handles;
1883     gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
1884     gatt_client_run();
1885     return ERROR_CODE_SUCCESS;
1886 }
1887 
1888 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){
1889     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
1890     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1891 
1892     if (value_length > (gatt_client->mtu - 3u)) return GATT_CLIENT_VALUE_TOO_LONG;
1893     if (!att_dispatch_client_can_send_now(gatt_client->con_handle)) return GATT_CLIENT_BUSY;
1894 
1895     return att_write_request(ATT_WRITE_COMMAND, gatt_client->con_handle, value_handle, value_length, value);
1896 }
1897 
1898 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){
1899     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1900     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1901     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1902 
1903     gatt_client->callback = callback;
1904     gatt_client->attribute_handle = value_handle;
1905     gatt_client->attribute_length = value_length;
1906     gatt_client->attribute_value = data;
1907     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
1908     gatt_client_run();
1909     return ERROR_CODE_SUCCESS;
1910 }
1911 
1912 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){
1913     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1914     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1915     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1916 
1917     gatt_client->callback = callback;
1918     gatt_client->attribute_handle = value_handle;
1919     gatt_client->attribute_length = value_length;
1920     gatt_client->attribute_offset = offset;
1921     gatt_client->attribute_value = data;
1922     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
1923     gatt_client_run();
1924     return ERROR_CODE_SUCCESS;
1925 }
1926 
1927 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){
1928     return gatt_client_write_long_value_of_characteristic_with_offset(callback, con_handle, value_handle, 0, value_length, value);
1929 }
1930 
1931 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){
1932     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1933     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1934     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1935 
1936     gatt_client->callback = callback;
1937     gatt_client->attribute_handle = value_handle;
1938     gatt_client->attribute_length = value_length;
1939     gatt_client->attribute_offset = 0;
1940     gatt_client->attribute_value = value;
1941     gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
1942     gatt_client_run();
1943     return ERROR_CODE_SUCCESS;
1944 }
1945 
1946 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){
1947     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1948     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1949     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1950 
1951     if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION) &&
1952         ((characteristic->properties & ATT_PROPERTY_NOTIFY) == 0u)) {
1953         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED");
1954         return GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED;
1955     } else if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_INDICATION) &&
1956                ((characteristic->properties & ATT_PROPERTY_INDICATE) == 0u)){
1957         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED");
1958         return GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED;
1959     }
1960 
1961     gatt_client->callback = callback;
1962     gatt_client->start_group_handle = characteristic->value_handle;
1963     gatt_client->end_group_handle = characteristic->end_handle;
1964     little_endian_store_16(gatt_client->client_characteristic_configuration_value, 0, configuration);
1965 
1966 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1967     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
1968 #else
1969     gatt_client->gatt_client_state = P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
1970 #endif
1971     gatt_client_run();
1972     return ERROR_CODE_SUCCESS;
1973 }
1974 
1975 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){
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->attribute_handle = descriptor_handle;
1982 
1983     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
1984     gatt_client_run();
1985     return ERROR_CODE_SUCCESS;
1986 }
1987 
1988 uint8_t gatt_client_read_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t * descriptor){
1989     return gatt_client_read_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
1990 }
1991 
1992 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){
1993     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1994     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1995     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1996 
1997     gatt_client->callback = callback;
1998     gatt_client->attribute_handle = descriptor_handle;
1999     gatt_client->attribute_offset = offset;
2000     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
2001     gatt_client_run();
2002     return ERROR_CODE_SUCCESS;
2003 }
2004 
2005 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){
2006     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0);
2007 }
2008 
2009 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){
2010     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
2011 }
2012 
2013 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){
2014     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2015     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2016     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2017 
2018     gatt_client->callback = callback;
2019     gatt_client->attribute_handle = descriptor_handle;
2020     gatt_client->attribute_length = length;
2021     gatt_client->attribute_offset = 0;
2022     gatt_client->attribute_value = data;
2023     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
2024     gatt_client_run();
2025     return ERROR_CODE_SUCCESS;
2026 }
2027 
2028 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){
2029     return gatt_client_write_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, length, value);
2030 }
2031 
2032 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){
2033     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2034     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2035     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2036 
2037     gatt_client->callback = callback;
2038     gatt_client->attribute_handle = descriptor_handle;
2039     gatt_client->attribute_length = length;
2040     gatt_client->attribute_offset = offset;
2041     gatt_client->attribute_value = data;
2042     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
2043     gatt_client_run();
2044     return ERROR_CODE_SUCCESS;
2045 }
2046 
2047 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){
2048     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0, length, data );
2049 }
2050 
2051 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){
2052     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, length, value);
2053 }
2054 
2055 /**
2056  * @brief -> gatt complete event
2057  */
2058 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){
2059     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2060     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2061     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2062 
2063     gatt_client->callback = callback;
2064     gatt_client->attribute_handle = attribute_handle;
2065     gatt_client->attribute_length = length;
2066     gatt_client->attribute_offset = offset;
2067     gatt_client->attribute_value = data;
2068     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
2069     gatt_client_run();
2070     return ERROR_CODE_SUCCESS;
2071 }
2072 
2073 /**
2074  * @brief -> gatt complete event
2075  */
2076 uint8_t gatt_client_execute_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2077     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2078 
2079     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2080     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2081 
2082     gatt_client->callback = callback;
2083     gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
2084     gatt_client_run();
2085     return ERROR_CODE_SUCCESS;
2086 }
2087 
2088 /**
2089  * @brief -> gatt complete event
2090  */
2091 uint8_t gatt_client_cancel_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2092     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2093     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2094     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2095 
2096     gatt_client->callback = callback;
2097     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
2098     gatt_client_run();
2099     return ERROR_CODE_SUCCESS;
2100 }
2101 
2102 void gatt_client_deserialize_service(const uint8_t *packet, int offset, gatt_client_service_t *service){
2103     service->start_group_handle = little_endian_read_16(packet, offset);
2104     service->end_group_handle = little_endian_read_16(packet, offset + 2);
2105     reverse_128(&packet[offset + 4], service->uuid128);
2106     if (uuid_has_bluetooth_prefix(service->uuid128)){
2107         service->uuid16 = big_endian_read_32(service->uuid128, 0);
2108     } else {
2109         service->uuid16 = 0;
2110     }
2111 }
2112 
2113 void gatt_client_deserialize_characteristic(const uint8_t * packet, int offset, gatt_client_characteristic_t * characteristic){
2114     characteristic->start_handle = little_endian_read_16(packet, offset);
2115     characteristic->value_handle = little_endian_read_16(packet, offset + 2);
2116     characteristic->end_handle = little_endian_read_16(packet, offset + 4);
2117     characteristic->properties = little_endian_read_16(packet, offset + 6);
2118     reverse_128(&packet[offset+8], characteristic->uuid128);
2119     if (uuid_has_bluetooth_prefix(characteristic->uuid128)){
2120         characteristic->uuid16 = big_endian_read_32(characteristic->uuid128, 0);
2121     } else {
2122         characteristic->uuid16 = 0;
2123     }
2124 }
2125 
2126 void gatt_client_deserialize_characteristic_descriptor(const uint8_t * packet, int offset, gatt_client_characteristic_descriptor_t * descriptor){
2127     descriptor->handle = little_endian_read_16(packet, offset);
2128     reverse_128(&packet[offset+2], descriptor->uuid128);
2129     if (uuid_has_bluetooth_prefix(descriptor->uuid128)){
2130         descriptor->uuid16 = big_endian_read_32(descriptor->uuid128, 0);
2131     } else {
2132         descriptor->uuid16 = 0;
2133     }
2134 }
2135 
2136 void gatt_client_send_mtu_negotiation(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2137     gatt_client_t * context = gatt_client_provide_context_for_handle(con_handle);
2138     if (context == NULL) return;
2139     if (context->mtu_state == MTU_AUTO_EXCHANGE_DISABLED){
2140         context->callback = callback;
2141         context->mtu_state = SEND_MTU_EXCHANGE;
2142         gatt_client_run();
2143     }
2144 }
2145 
2146 uint8_t gatt_client_request_can_write_without_response_event(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2147     gatt_client_t * context = gatt_client_provide_context_for_handle(con_handle);
2148     if (context == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2149     if (context->write_without_response_callback != NULL) return GATT_CLIENT_IN_WRONG_STATE;
2150     context->write_without_response_callback = callback;
2151     att_dispatch_client_request_can_send_now_event(context->con_handle);
2152     return ERROR_CODE_SUCCESS;
2153 }
2154 
2155 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
2156 void gatt_client_att_packet_handler_fuzz(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
2157     gatt_client_att_packet_handler(packet_type, handle, packet, size);
2158 }
2159 #endif
2160