xref: /btstack/src/ble/gatt_client.c (revision 6ccd8248590f666db07dd7add13fecb4f5664fb5)
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     uint8_t error_code;
1202     switch (packet[0]){
1203         case ATT_EXCHANGE_MTU_RESPONSE:
1204         {
1205             if (size < 3u) break;
1206             uint16_t remote_rx_mtu = little_endian_read_16(packet, 1);
1207             uint16_t local_rx_mtu = l2cap_max_le_mtu();
1208             gatt_client->mtu = (remote_rx_mtu < local_rx_mtu) ? remote_rx_mtu : local_rx_mtu;
1209             gatt_client->mtu_state = MTU_EXCHANGED;
1210             emit_gatt_mtu_exchanged_result_event(gatt_client, gatt_client->mtu);
1211             break;
1212         }
1213         case ATT_READ_BY_GROUP_TYPE_RESPONSE:
1214             switch(gatt_client->gatt_client_state){
1215                 case P_W4_SERVICE_QUERY_RESULT:
1216                     report_gatt_services(gatt_client, packet, size);
1217                     trigger_next_service_query(gatt_client, get_last_result_handle_from_service_list(packet, size));
1218                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1219                     break;
1220                 default:
1221                     break;
1222             }
1223             break;
1224         case ATT_HANDLE_VALUE_INDICATION:
1225             if (size < 3u) break;
1226             report_gatt_indication(handle, little_endian_read_16(packet,1u), &packet[3], size-3u);
1227             gatt_client->send_confirmation = 1;
1228             break;
1229 
1230         case ATT_READ_BY_TYPE_RESPONSE:
1231             switch (gatt_client->gatt_client_state){
1232                 case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1233                     report_gatt_characteristics(gatt_client, packet, size);
1234                     trigger_next_characteristic_query(gatt_client, get_last_result_handle_from_characteristics_list(packet, size));
1235                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1236                     break;
1237                 case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1238                     report_gatt_characteristics(gatt_client, packet, size);
1239                     trigger_next_characteristic_query(gatt_client, get_last_result_handle_from_characteristics_list(packet, size));
1240                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done, or by ATT_ERROR
1241                     break;
1242                 case P_W4_INCLUDED_SERVICE_QUERY_RESULT:
1243                 {
1244                     if (size < 2u) break;
1245                     uint16_t uuid16 = 0;
1246                     uint16_t pair_size = packet[1];
1247 
1248                     if (pair_size == 6u){
1249                         if (size < 8u) break;
1250                         // UUIDs not available, query first included service
1251                         gatt_client->start_group_handle = little_endian_read_16(packet, 2); // ready for next query
1252                         gatt_client->query_start_handle = little_endian_read_16(packet, 4);
1253                         gatt_client->query_end_handle = little_endian_read_16(packet, 6);
1254                         gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_WITH_UUID_QUERY;
1255                         break;
1256                     }
1257 
1258                     if (pair_size != 8u) break;
1259 
1260                     // UUIDs included, report all of them
1261                     uint16_t offset;
1262                     for (offset = 2u; (offset + 8u) <= size; offset += pair_size){
1263                         uint16_t include_handle = little_endian_read_16(packet, offset);
1264                         gatt_client->query_start_handle = little_endian_read_16(packet, offset + 2u);
1265                         gatt_client->query_end_handle = little_endian_read_16(packet, offset + 4u);
1266                         uuid16 = little_endian_read_16(packet, offset+6u);
1267                         report_gatt_included_service_uuid16(gatt_client, include_handle, uuid16);
1268                     }
1269 
1270                     trigger_next_included_service_query(gatt_client, get_last_result_handle_from_included_services_list(packet, size));
1271                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1272                     break;
1273                 }
1274 #ifndef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1275                 case P_W4_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT:
1276                     gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, 2);
1277                     gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1278                     break;
1279 #endif
1280                 case P_W4_READ_BY_TYPE_RESPONSE: {
1281                     uint16_t pair_size = packet[1];
1282                     uint16_t offset;
1283                     uint16_t last_result_handle = 0;
1284                     for (offset = 2; offset < size ; offset += pair_size){
1285                         uint16_t value_handle = little_endian_read_16(packet, offset);
1286                         report_gatt_characteristic_value(gatt_client, value_handle, &packet[offset + 2u], pair_size - 2u);
1287                         last_result_handle = value_handle;
1288                     }
1289                     trigger_next_read_by_type_query(gatt_client, last_result_handle);
1290                     break;
1291                 }
1292                 default:
1293                     break;
1294             }
1295             break;
1296         case ATT_READ_RESPONSE:
1297             switch (gatt_client->gatt_client_state){
1298                 case P_W4_INCLUDED_SERVICE_UUID_WITH_QUERY_RESULT: {
1299                     uint8_t uuid128[16];
1300                     reverse_128(&packet[1], uuid128);
1301                     report_gatt_included_service_uuid128(gatt_client, gatt_client->start_group_handle, uuid128);
1302                     trigger_next_included_service_query(gatt_client, gatt_client->start_group_handle);
1303                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1304                     break;
1305                 }
1306                 case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1307                     gatt_client_handle_transaction_complete(gatt_client);
1308                     report_gatt_characteristic_value(gatt_client, gatt_client->attribute_handle, &packet[1], size - 1u);
1309                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1310                     break;
1311 
1312                 case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:{
1313                     gatt_client_handle_transaction_complete(gatt_client);
1314                     report_gatt_characteristic_descriptor(gatt_client, gatt_client->attribute_handle, &packet[1], size - 1u, 0u);
1315                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1316                     break;
1317                 }
1318                 default:
1319                     break;
1320             }
1321             break;
1322 
1323         case ATT_FIND_BY_TYPE_VALUE_RESPONSE:
1324         {
1325             uint8_t pair_size = 4;
1326             int i;
1327             uint16_t start_group_handle;
1328             uint16_t   end_group_handle= 0xffff; // asserts GATT_EVENT_QUERY_COMPLETE is emitted if no results
1329             for (i = 1u; (i + pair_size) <= size; i += pair_size){
1330                 start_group_handle = little_endian_read_16(packet,i);
1331                 end_group_handle = little_endian_read_16(packet,i+2);
1332                 emit_gatt_service_query_result_event(gatt_client, start_group_handle, end_group_handle, gatt_client->uuid128);
1333             }
1334             trigger_next_service_by_uuid_query(gatt_client, end_group_handle);
1335             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1336             break;
1337         }
1338         case ATT_FIND_INFORMATION_REPLY:
1339         {
1340             if (size < 2u) break;
1341 
1342             uint8_t pair_size = 4;
1343             if (packet[1u] == 2u){
1344                 pair_size = 18;
1345             }
1346             uint16_t offset = 2;
1347 
1348             if (size < (pair_size + offset)) break;
1349             uint16_t last_descriptor_handle = little_endian_read_16(packet, size - pair_size);
1350 
1351 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1352             log_info("ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY, state %x", gatt_client->gatt_client_state);
1353             if (gatt_client->gatt_client_state == P_W4_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY_RESULT){
1354                 // iterate over descriptors looking for CCC
1355                 if (pair_size == 4){
1356                     while ((offset + 4) <= size){
1357                         uint16_t uuid16 = little_endian_read_16(packet, offset + 2);
1358                         if (uuid16 == GATT_CLIENT_CHARACTERISTICS_CONFIGURATION){
1359                             gatt_client->client_characteristic_configuration_handle = little_endian_read_16(packet, offset);
1360                             gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1361                             log_info("CCC found %x", gatt_client->client_characteristic_configuration_handle);
1362                             break;
1363                         }
1364                         offset += pair_size;
1365                     }
1366                 }
1367                 if (is_query_done(gatt_client, last_descriptor_handle)){
1368 
1369                 } else {
1370                     // next
1371                     gatt_client->start_group_handle = last_descriptor_handle + 1;
1372                     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
1373                 }
1374                 break;
1375             }
1376 #endif
1377             report_gatt_all_characteristic_descriptors(gatt_client, &packet[2], size - 2u, pair_size);
1378             trigger_next_characteristic_descriptor_query(gatt_client, last_descriptor_handle);
1379             // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1380             break;
1381         }
1382 
1383         case ATT_WRITE_RESPONSE:
1384             switch (gatt_client->gatt_client_state){
1385                 case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1386                     gatt_client_handle_transaction_complete(gatt_client);
1387                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1388                     break;
1389                 case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1390                     gatt_client_handle_transaction_complete(gatt_client);
1391                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1392                     break;
1393                 case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1394                     gatt_client_handle_transaction_complete(gatt_client);
1395                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1396                     break;
1397                 default:
1398                     break;
1399             }
1400             break;
1401 
1402         case ATT_READ_BLOB_RESPONSE:{
1403             uint16_t received_blob_length = size-1u;
1404             switch(gatt_client->gatt_client_state){
1405                 case P_W4_READ_BLOB_RESULT:
1406                     report_gatt_long_characteristic_value_blob(gatt_client, gatt_client->attribute_handle, &packet[1], received_blob_length, gatt_client->attribute_offset);
1407                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_QUERY, received_blob_length);
1408                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1409                     break;
1410                 case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1411                     report_gatt_long_characteristic_descriptor(gatt_client, gatt_client->attribute_handle,
1412                                                                &packet[1], received_blob_length,
1413                                                                gatt_client->attribute_offset);
1414                     trigger_next_blob_query(gatt_client, P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY, received_blob_length);
1415                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1416                     break;
1417                 default:
1418                     break;
1419             }
1420             break;
1421         }
1422         case ATT_PREPARE_WRITE_RESPONSE:
1423             switch (gatt_client->gatt_client_state){
1424                 case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1425                     gatt_client_handle_transaction_complete(gatt_client);
1426                     if (is_value_valid(gatt_client, packet, size)){
1427                         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1428                     } else {
1429                         emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1430                     }
1431                     break;
1432 
1433                 case P_W4_PREPARE_WRITE_RESULT:{
1434                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1435                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE, P_W2_EXECUTE_PREPARED_WRITE);
1436                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1437                     break;
1438                 }
1439                 case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:{
1440                     gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1441                     trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR, P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR);
1442                     // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1443                     break;
1444                 }
1445                 case P_W4_PREPARE_RELIABLE_WRITE_RESULT:{
1446                     if (is_value_valid(gatt_client, packet, size)){
1447                         gatt_client->attribute_offset = little_endian_read_16(packet, 3);
1448                         trigger_next_prepare_write_query(gatt_client, P_W2_PREPARE_RELIABLE_WRITE, P_W2_EXECUTE_PREPARED_WRITE);
1449                         // GATT_EVENT_QUERY_COMPLETE is emitted by trigger_next_xxx when done
1450                         break;
1451                     }
1452                     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1453                     break;
1454                 }
1455                 default:
1456                     break;
1457             }
1458             break;
1459 
1460         case ATT_EXECUTE_WRITE_RESPONSE:
1461             switch (gatt_client->gatt_client_state){
1462                 case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1463                     gatt_client_handle_transaction_complete(gatt_client);
1464                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1465                     break;
1466                 case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1467                     gatt_client_handle_transaction_complete(gatt_client);
1468                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1469                     break;
1470                 case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1471                     gatt_client_handle_transaction_complete(gatt_client);
1472                     emit_gatt_complete_event(gatt_client, ATT_ERROR_DATA_MISMATCH);
1473                     break;
1474                 case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1475                     gatt_client_handle_transaction_complete(gatt_client);
1476                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1477                     break;
1478                 default:
1479                     break;
1480 
1481             }
1482             break;
1483 
1484         case ATT_READ_MULTIPLE_RESPONSE:
1485             switch(gatt_client->gatt_client_state){
1486                 case P_W4_READ_MULTIPLE_RESPONSE:
1487                     report_gatt_characteristic_value(gatt_client, 0u, &packet[1], size - 1u);
1488                     gatt_client_handle_transaction_complete(gatt_client);
1489                     emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1490                     break;
1491                 default:
1492                     break;
1493             }
1494             break;
1495 
1496         case ATT_ERROR_RESPONSE:
1497             if (size < 5u) return;
1498             error_code = packet[4];
1499             switch (error_code){
1500                 case ATT_ERROR_ATTRIBUTE_NOT_FOUND: {
1501                     switch(gatt_client->gatt_client_state){
1502                         case P_W4_SERVICE_QUERY_RESULT:
1503                         case P_W4_SERVICE_WITH_UUID_RESULT:
1504                         case P_W4_INCLUDED_SERVICE_QUERY_RESULT:
1505                         case P_W4_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT:
1506                             gatt_client_handle_transaction_complete(gatt_client);
1507                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1508                             break;
1509                         case P_W4_ALL_CHARACTERISTICS_OF_SERVICE_QUERY_RESULT:
1510                         case P_W4_CHARACTERISTIC_WITH_UUID_QUERY_RESULT:
1511                             characteristic_end_found(gatt_client, gatt_client->end_group_handle);
1512                             gatt_client_handle_transaction_complete(gatt_client);
1513                             emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1514                             break;
1515                         case P_W4_READ_BY_TYPE_RESPONSE:
1516                             gatt_client_handle_transaction_complete(gatt_client);
1517                             if (gatt_client->start_group_handle == gatt_client->query_start_handle){
1518                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_ATTRIBUTE_NOT_FOUND);
1519                             } else {
1520                                 emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1521                             }
1522                             break;
1523                         default:
1524                             gatt_client_report_error_if_pending(gatt_client, error_code);
1525                             break;
1526                     }
1527                     break;
1528                 }
1529 
1530 #ifdef ENABLE_GATT_CLIENT_PAIRING
1531 
1532                 case ATT_ERROR_INSUFFICIENT_AUTHENTICATION:
1533                 case ATT_ERROR_INSUFFICIENT_ENCRYPTION_KEY_SIZE:
1534                 case ATT_ERROR_INSUFFICIENT_ENCRYPTION: {
1535 
1536                     // security too low
1537                     if (gatt_client->security_counter > 0) {
1538                         gatt_client_report_error_if_pending(gatt_client, error_code);
1539                         break;
1540                     }
1541                     // start security
1542                     gatt_client->security_counter++;
1543 
1544                     // setup action
1545                     int retry = 1;
1546                     switch (gatt_client->gatt_client_state){
1547                         case P_W4_READ_CHARACTERISTIC_VALUE_RESULT:
1548                             gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY ;
1549                             break;
1550                         case P_W4_READ_BLOB_RESULT:
1551                             gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
1552                             break;
1553                         case P_W4_READ_BY_TYPE_RESPONSE:
1554                             gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1555                             break;
1556                         case P_W4_READ_MULTIPLE_RESPONSE:
1557                             gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
1558                             break;
1559                         case P_W4_WRITE_CHARACTERISTIC_VALUE_RESULT:
1560                             gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
1561                             break;
1562                         case P_W4_PREPARE_WRITE_RESULT:
1563                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
1564                             break;
1565                         case P_W4_PREPARE_WRITE_SINGLE_RESULT:
1566                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
1567                             break;
1568                         case P_W4_PREPARE_RELIABLE_WRITE_RESULT:
1569                             gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
1570                             break;
1571                         case P_W4_EXECUTE_PREPARED_WRITE_RESULT:
1572                             gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
1573                             break;
1574                         case P_W4_CANCEL_PREPARED_WRITE_RESULT:
1575                             gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
1576                             break;
1577                         case P_W4_CANCEL_PREPARED_WRITE_DATA_MISMATCH_RESULT:
1578                             gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE_DATA_MISMATCH;
1579                             break;
1580                         case P_W4_READ_CHARACTERISTIC_DESCRIPTOR_RESULT:
1581                             gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
1582                             break;
1583                         case P_W4_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_RESULT:
1584                             gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
1585                             break;
1586                         case P_W4_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1587                             gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
1588                             break;
1589                         case P_W4_CLIENT_CHARACTERISTIC_CONFIGURATION_RESULT:
1590                             gatt_client->gatt_client_state = P_W2_WRITE_CLIENT_CHARACTERISTIC_CONFIGURATION;
1591                             break;
1592                         case P_W4_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1593                             gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
1594                             break;
1595                         case P_W4_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR_RESULT:
1596                             gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE_CHARACTERISTIC_DESCRIPTOR;
1597                             break;
1598 #ifdef ENABLE_LE_SIGNED_WRITE
1599                         case P_W4_SEND_SINGED_WRITE_DONE:
1600                             gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1601                             break;
1602 #endif
1603                         default:
1604                             log_info("retry not supported for state %x", gatt_client->gatt_client_state);
1605                             retry = 0;
1606                             break;
1607                     }
1608 
1609                     if (!retry) {
1610                         gatt_client_report_error_if_pending(gatt_client, error_code);
1611                         break;
1612                     }
1613 
1614                     log_info("security error, start pairing");
1615 
1616                     // start pairing for higher security level
1617                     gatt_client->wait_for_pairing_complete = 1;
1618                     gatt_client->pending_error_code = error_code;
1619                     sm_request_pairing(gatt_client->con_handle);
1620                     break;
1621                 }
1622 #endif
1623 
1624                 // nothing we can do about that
1625                 case ATT_ERROR_INSUFFICIENT_AUTHORIZATION:
1626                 default:
1627                     gatt_client_report_error_if_pending(gatt_client, error_code);
1628                     break;
1629             }
1630             break;
1631 
1632         default:
1633             log_info("ATT Handler, unhandled response type 0x%02x", packet[0]);
1634             break;
1635     }
1636     gatt_client_run();
1637 }
1638 
1639 #ifdef ENABLE_LE_SIGNED_WRITE
1640 static void att_signed_write_handle_cmac_result(uint8_t hash[8]){
1641     btstack_linked_list_iterator_t it;
1642     btstack_linked_list_iterator_init(&it, &gatt_client_connections);
1643     while (btstack_linked_list_iterator_has_next(&it)){
1644         gatt_client_t * gatt_client = (gatt_client_t *) btstack_linked_list_iterator_next(&it);
1645         if (gatt_client->gatt_client_state == P_W4_CMAC_RESULT){
1646             // store result
1647             (void)memcpy(gatt_client->cmac, hash, 8);
1648             // reverse_64(hash, gatt_client->cmac);
1649             gatt_client->gatt_client_state = P_W2_SEND_SIGNED_WRITE;
1650             gatt_client_run();
1651             return;
1652         }
1653     }
1654 }
1655 
1656 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){
1657     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
1658     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1659     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1660 
1661     gatt_client->callback = callback;
1662     gatt_client->attribute_handle = handle;
1663     gatt_client->attribute_length = message_len;
1664     gatt_client->attribute_value = message;
1665     gatt_client->gatt_client_state = P_W4_IDENTITY_RESOLVING;
1666     gatt_client_run();
1667     return ERROR_CODE_SUCCESS;
1668 }
1669 #endif
1670 
1671 uint8_t gatt_client_discover_primary_services(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
1672     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1673     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1674     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1675 
1676     gatt_client->callback = callback;
1677     gatt_client->start_group_handle = 0x0001;
1678     gatt_client->end_group_handle   = 0xffff;
1679     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_QUERY;
1680     gatt_client->uuid16 = 0;
1681     gatt_client_run();
1682     return ERROR_CODE_SUCCESS;
1683 }
1684 
1685 
1686 uint8_t gatt_client_discover_primary_services_by_uuid16(btstack_packet_handler_t callback, hci_con_handle_t con_handle, uint16_t uuid16){
1687     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1688     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1689     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1690 
1691     gatt_client->callback = callback;
1692     gatt_client->start_group_handle = 0x0001;
1693     gatt_client->end_group_handle   = 0xffff;
1694     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
1695     gatt_client->uuid16 = uuid16;
1696     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), gatt_client->uuid16);
1697     gatt_client_run();
1698     return ERROR_CODE_SUCCESS;
1699 }
1700 
1701 uint8_t gatt_client_discover_primary_services_by_uuid128(btstack_packet_handler_t callback, hci_con_handle_t con_handle, const uint8_t * uuid128){
1702     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1703     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1704     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1705 
1706     gatt_client->callback = callback;
1707     gatt_client->start_group_handle = 0x0001;
1708     gatt_client->end_group_handle   = 0xffff;
1709     gatt_client->uuid16 = 0;
1710     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1711     gatt_client->gatt_client_state = P_W2_SEND_SERVICE_WITH_UUID_QUERY;
1712     gatt_client_run();
1713     return ERROR_CODE_SUCCESS;
1714 }
1715 
1716 uint8_t gatt_client_discover_characteristics_for_service(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_service_t *service){
1717     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1718     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1719     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1720 
1721     gatt_client->callback = callback;
1722     gatt_client->start_group_handle = service->start_group_handle;
1723     gatt_client->end_group_handle   = service->end_group_handle;
1724     gatt_client->filter_with_uuid = 0;
1725     gatt_client->characteristic_start_handle = 0;
1726     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTICS_OF_SERVICE_QUERY;
1727     gatt_client_run();
1728     return ERROR_CODE_SUCCESS;
1729 }
1730 
1731 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){
1732     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1733     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1734     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1735     gatt_client->callback = callback;
1736     gatt_client->start_group_handle = service->start_group_handle;
1737     gatt_client->end_group_handle   = service->end_group_handle;
1738     gatt_client->gatt_client_state = P_W2_SEND_INCLUDED_SERVICE_QUERY;
1739 
1740     gatt_client_run();
1741     return ERROR_CODE_SUCCESS;
1742 }
1743 
1744 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){
1745     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1746     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1747     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1748 
1749     gatt_client->callback = callback;
1750     gatt_client->start_group_handle = start_handle;
1751     gatt_client->end_group_handle   = end_handle;
1752     gatt_client->filter_with_uuid = 1;
1753     gatt_client->uuid16 = uuid16;
1754     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
1755     gatt_client->characteristic_start_handle = 0;
1756     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
1757     gatt_client_run();
1758     return ERROR_CODE_SUCCESS;
1759 }
1760 
1761 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){
1762     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1763     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1764     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1765 
1766     gatt_client->callback = callback;
1767     gatt_client->start_group_handle = start_handle;
1768     gatt_client->end_group_handle   = end_handle;
1769     gatt_client->filter_with_uuid = 1;
1770     gatt_client->uuid16 = 0;
1771     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1772     gatt_client->characteristic_start_handle = 0;
1773     gatt_client->gatt_client_state = P_W2_SEND_CHARACTERISTIC_WITH_UUID_QUERY;
1774     gatt_client_run();
1775     return ERROR_CODE_SUCCESS;
1776 }
1777 
1778 
1779 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){
1780     return gatt_client_discover_characteristics_for_handle_range_by_uuid16(callback, handle, service->start_group_handle, service->end_group_handle, uuid16);
1781 }
1782 
1783 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){
1784     return gatt_client_discover_characteristics_for_handle_range_by_uuid128(callback, handle, service->start_group_handle, service->end_group_handle, uuid128);
1785 }
1786 
1787 uint8_t gatt_client_discover_characteristic_descriptors(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_t *characteristic){
1788     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1789     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1790     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1791 
1792     if (characteristic->value_handle == characteristic->end_handle){
1793         emit_gatt_complete_event(gatt_client, ATT_ERROR_SUCCESS);
1794         return ERROR_CODE_SUCCESS;
1795     }
1796     gatt_client->callback = callback;
1797     gatt_client->start_group_handle = characteristic->value_handle + 1u;
1798     gatt_client->end_group_handle   = characteristic->end_handle;
1799     gatt_client->gatt_client_state = P_W2_SEND_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY;
1800     gatt_client_run();
1801     return ERROR_CODE_SUCCESS;
1802 }
1803 
1804 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){
1805     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1806     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1807     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1808 
1809     gatt_client->callback = callback;
1810     gatt_client->attribute_handle = value_handle;
1811     gatt_client->attribute_offset = 0;
1812     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_VALUE_QUERY;
1813     gatt_client_run();
1814     return ERROR_CODE_SUCCESS;
1815 }
1816 
1817 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){
1818     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1819     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1820     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1821 
1822     gatt_client->callback = callback;
1823     gatt_client->start_group_handle = start_handle;
1824     gatt_client->end_group_handle = end_handle;
1825     gatt_client->query_start_handle = start_handle;
1826     gatt_client->query_end_handle = end_handle;
1827     gatt_client->uuid16 = uuid16;
1828     uuid_add_bluetooth_prefix((uint8_t*) &(gatt_client->uuid128), uuid16);
1829     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1830     gatt_client_run();
1831     return ERROR_CODE_SUCCESS;
1832 }
1833 
1834 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){
1835     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1836     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1837     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1838 
1839     gatt_client->callback = callback;
1840     gatt_client->start_group_handle = start_handle;
1841     gatt_client->end_group_handle = end_handle;
1842     gatt_client->query_start_handle = start_handle;
1843     gatt_client->query_end_handle = end_handle;
1844     gatt_client->uuid16 = 0;
1845     (void)memcpy(gatt_client->uuid128, uuid128, 16);
1846     gatt_client->gatt_client_state = P_W2_SEND_READ_BY_TYPE_REQUEST;
1847     gatt_client_run();
1848     return ERROR_CODE_SUCCESS;
1849 }
1850 
1851 
1852 uint8_t gatt_client_read_value_of_characteristic(btstack_packet_handler_t callback, uint16_t handle, gatt_client_characteristic_t *characteristic){
1853     return gatt_client_read_value_of_characteristic_using_value_handle(callback, handle, characteristic->value_handle);
1854 }
1855 
1856 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){
1857     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1858     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1859     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1860 
1861     gatt_client->callback = callback;
1862     gatt_client->attribute_handle = characteristic_value_handle;
1863     gatt_client->attribute_offset = offset;
1864     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_QUERY;
1865     gatt_client_run();
1866     return ERROR_CODE_SUCCESS;
1867 }
1868 
1869 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){
1870     return gatt_client_read_long_value_of_characteristic_using_value_handle_with_offset(callback, con_handle, characteristic_value_handle, 0);
1871 }
1872 
1873 uint8_t gatt_client_read_long_value_of_characteristic(btstack_packet_handler_t callback, uint16_t handle, gatt_client_characteristic_t *characteristic){
1874     return gatt_client_read_long_value_of_characteristic_using_value_handle(callback, handle, characteristic->value_handle);
1875 }
1876 
1877 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){
1878     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1879     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1880     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1881 
1882     gatt_client->callback = callback;
1883     gatt_client->read_multiple_handle_count = num_value_handles;
1884     gatt_client->read_multiple_handles = value_handles;
1885     gatt_client->gatt_client_state = P_W2_SEND_READ_MULTIPLE_REQUEST;
1886     gatt_client_run();
1887     return ERROR_CODE_SUCCESS;
1888 }
1889 
1890 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){
1891     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle(con_handle);
1892     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1893 
1894     if (value_length > (gatt_client->mtu - 3u)) return GATT_CLIENT_VALUE_TOO_LONG;
1895     if (!att_dispatch_client_can_send_now(gatt_client->con_handle)) return GATT_CLIENT_BUSY;
1896 
1897     return att_write_request(ATT_WRITE_COMMAND, gatt_client->con_handle, value_handle, value_length, value);
1898 }
1899 
1900 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){
1901     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1902     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1903     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1904 
1905     gatt_client->callback = callback;
1906     gatt_client->attribute_handle = value_handle;
1907     gatt_client->attribute_length = value_length;
1908     gatt_client->attribute_value = data;
1909     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_VALUE;
1910     gatt_client_run();
1911     return ERROR_CODE_SUCCESS;
1912 }
1913 
1914 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){
1915     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1916     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1917     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1918 
1919     gatt_client->callback = callback;
1920     gatt_client->attribute_handle = value_handle;
1921     gatt_client->attribute_length = value_length;
1922     gatt_client->attribute_offset = offset;
1923     gatt_client->attribute_value = data;
1924     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE;
1925     gatt_client_run();
1926     return ERROR_CODE_SUCCESS;
1927 }
1928 
1929 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){
1930     return gatt_client_write_long_value_of_characteristic_with_offset(callback, con_handle, value_handle, 0, value_length, value);
1931 }
1932 
1933 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){
1934     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1935     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1936     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1937 
1938     gatt_client->callback = callback;
1939     gatt_client->attribute_handle = value_handle;
1940     gatt_client->attribute_length = value_length;
1941     gatt_client->attribute_offset = 0;
1942     gatt_client->attribute_value = value;
1943     gatt_client->gatt_client_state = P_W2_PREPARE_RELIABLE_WRITE;
1944     gatt_client_run();
1945     return ERROR_CODE_SUCCESS;
1946 }
1947 
1948 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){
1949     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1950     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1951     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1952 
1953     if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION) &&
1954         ((characteristic->properties & ATT_PROPERTY_NOTIFY) == 0u)) {
1955         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED");
1956         return GATT_CLIENT_CHARACTERISTIC_NOTIFICATION_NOT_SUPPORTED;
1957     } else if ( (configuration & GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_INDICATION) &&
1958                ((characteristic->properties & ATT_PROPERTY_INDICATE) == 0u)){
1959         log_info("gatt_client_write_client_characteristic_configuration: GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED");
1960         return GATT_CLIENT_CHARACTERISTIC_INDICATION_NOT_SUPPORTED;
1961     }
1962 
1963     gatt_client->callback = callback;
1964     gatt_client->start_group_handle = characteristic->value_handle;
1965     gatt_client->end_group_handle = characteristic->end_handle;
1966     little_endian_store_16(gatt_client->client_characteristic_configuration_value, 0, configuration);
1967 
1968 #ifdef ENABLE_GATT_FIND_INFORMATION_FOR_CCC_DISCOVERY
1969     gatt_client->gatt_client_state = P_W2_SEND_FIND_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
1970 #else
1971     gatt_client->gatt_client_state = P_W2_SEND_READ_CLIENT_CHARACTERISTIC_CONFIGURATION_QUERY;
1972 #endif
1973     gatt_client_run();
1974     return ERROR_CODE_SUCCESS;
1975 }
1976 
1977 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){
1978     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1979     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1980     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1981 
1982     gatt_client->callback = callback;
1983     gatt_client->attribute_handle = descriptor_handle;
1984 
1985     gatt_client->gatt_client_state = P_W2_SEND_READ_CHARACTERISTIC_DESCRIPTOR_QUERY;
1986     gatt_client_run();
1987     return ERROR_CODE_SUCCESS;
1988 }
1989 
1990 uint8_t gatt_client_read_characteristic_descriptor(btstack_packet_handler_t callback, hci_con_handle_t con_handle, gatt_client_characteristic_descriptor_t * descriptor){
1991     return gatt_client_read_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
1992 }
1993 
1994 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){
1995     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
1996     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
1997     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
1998 
1999     gatt_client->callback = callback;
2000     gatt_client->attribute_handle = descriptor_handle;
2001     gatt_client->attribute_offset = offset;
2002     gatt_client->gatt_client_state = P_W2_SEND_READ_BLOB_CHARACTERISTIC_DESCRIPTOR_QUERY;
2003     gatt_client_run();
2004     return ERROR_CODE_SUCCESS;
2005 }
2006 
2007 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){
2008     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0);
2009 }
2010 
2011 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){
2012     return gatt_client_read_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle);
2013 }
2014 
2015 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){
2016     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2017     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2018     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2019 
2020     gatt_client->callback = callback;
2021     gatt_client->attribute_handle = descriptor_handle;
2022     gatt_client->attribute_length = length;
2023     gatt_client->attribute_offset = 0;
2024     gatt_client->attribute_value = data;
2025     gatt_client->gatt_client_state = P_W2_SEND_WRITE_CHARACTERISTIC_DESCRIPTOR;
2026     gatt_client_run();
2027     return ERROR_CODE_SUCCESS;
2028 }
2029 
2030 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){
2031     return gatt_client_write_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, length, value);
2032 }
2033 
2034 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){
2035     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2036     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2037     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2038 
2039     gatt_client->callback = callback;
2040     gatt_client->attribute_handle = descriptor_handle;
2041     gatt_client->attribute_length = length;
2042     gatt_client->attribute_offset = offset;
2043     gatt_client->attribute_value = data;
2044     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_CHARACTERISTIC_DESCRIPTOR;
2045     gatt_client_run();
2046     return ERROR_CODE_SUCCESS;
2047 }
2048 
2049 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){
2050     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle_with_offset(callback, con_handle, descriptor_handle, 0, length, data );
2051 }
2052 
2053 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){
2054     return gatt_client_write_long_characteristic_descriptor_using_descriptor_handle(callback, con_handle, descriptor->handle, length, value);
2055 }
2056 
2057 /**
2058  * @brief -> gatt complete event
2059  */
2060 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){
2061     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2062     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2063     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2064 
2065     gatt_client->callback = callback;
2066     gatt_client->attribute_handle = attribute_handle;
2067     gatt_client->attribute_length = length;
2068     gatt_client->attribute_offset = offset;
2069     gatt_client->attribute_value = data;
2070     gatt_client->gatt_client_state = P_W2_PREPARE_WRITE_SINGLE;
2071     gatt_client_run();
2072     return ERROR_CODE_SUCCESS;
2073 }
2074 
2075 /**
2076  * @brief -> gatt complete event
2077  */
2078 uint8_t gatt_client_execute_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2079     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2080 
2081     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2082     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2083 
2084     gatt_client->callback = callback;
2085     gatt_client->gatt_client_state = P_W2_EXECUTE_PREPARED_WRITE;
2086     gatt_client_run();
2087     return ERROR_CODE_SUCCESS;
2088 }
2089 
2090 /**
2091  * @brief -> gatt complete event
2092  */
2093 uint8_t gatt_client_cancel_write(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2094     gatt_client_t * gatt_client = gatt_client_provide_context_for_handle_and_start_timer(con_handle);
2095     if (gatt_client == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2096     if (is_ready(gatt_client) == 0) return GATT_CLIENT_IN_WRONG_STATE;
2097 
2098     gatt_client->callback = callback;
2099     gatt_client->gatt_client_state = P_W2_CANCEL_PREPARED_WRITE;
2100     gatt_client_run();
2101     return ERROR_CODE_SUCCESS;
2102 }
2103 
2104 void gatt_client_deserialize_service(const uint8_t *packet, int offset, gatt_client_service_t *service){
2105     service->start_group_handle = little_endian_read_16(packet, offset);
2106     service->end_group_handle = little_endian_read_16(packet, offset + 2);
2107     reverse_128(&packet[offset + 4], service->uuid128);
2108     if (uuid_has_bluetooth_prefix(service->uuid128)){
2109         service->uuid16 = big_endian_read_32(service->uuid128, 0);
2110     } else {
2111         service->uuid16 = 0;
2112     }
2113 }
2114 
2115 void gatt_client_deserialize_characteristic(const uint8_t * packet, int offset, gatt_client_characteristic_t * characteristic){
2116     characteristic->start_handle = little_endian_read_16(packet, offset);
2117     characteristic->value_handle = little_endian_read_16(packet, offset + 2);
2118     characteristic->end_handle = little_endian_read_16(packet, offset + 4);
2119     characteristic->properties = little_endian_read_16(packet, offset + 6);
2120     reverse_128(&packet[offset+8], characteristic->uuid128);
2121     if (uuid_has_bluetooth_prefix(characteristic->uuid128)){
2122         characteristic->uuid16 = big_endian_read_32(characteristic->uuid128, 0);
2123     } else {
2124         characteristic->uuid16 = 0;
2125     }
2126 }
2127 
2128 void gatt_client_deserialize_characteristic_descriptor(const uint8_t * packet, int offset, gatt_client_characteristic_descriptor_t * descriptor){
2129     descriptor->handle = little_endian_read_16(packet, offset);
2130     reverse_128(&packet[offset+2], descriptor->uuid128);
2131     if (uuid_has_bluetooth_prefix(descriptor->uuid128)){
2132         descriptor->uuid16 = big_endian_read_32(descriptor->uuid128, 0);
2133     } else {
2134         descriptor->uuid16 = 0;
2135     }
2136 }
2137 
2138 void gatt_client_send_mtu_negotiation(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2139     gatt_client_t * context = gatt_client_provide_context_for_handle(con_handle);
2140     if (context == NULL) return;
2141     if (context->mtu_state == MTU_AUTO_EXCHANGE_DISABLED){
2142         context->callback = callback;
2143         context->mtu_state = SEND_MTU_EXCHANGE;
2144         gatt_client_run();
2145     }
2146 }
2147 
2148 uint8_t gatt_client_request_can_write_without_response_event(btstack_packet_handler_t callback, hci_con_handle_t con_handle){
2149     gatt_client_t * context = gatt_client_provide_context_for_handle(con_handle);
2150     if (context == NULL) return BTSTACK_MEMORY_ALLOC_FAILED;
2151     if (context->write_without_response_callback != NULL) return GATT_CLIENT_IN_WRONG_STATE;
2152     context->write_without_response_callback = callback;
2153     att_dispatch_client_request_can_send_now_event(context->con_handle);
2154     return ERROR_CODE_SUCCESS;
2155 }
2156 
2157 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
2158 void gatt_client_att_packet_handler_fuzz(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){
2159     gatt_client_att_packet_handler(packet_type, handle, packet, size);
2160 }
2161 #endif
2162