xref: /btstack/src/ble/gatt-service/hids_client.c (revision f4d3b82a97d7d1bd03d0b27f0a50318d9f14b6d4)
1 /*
2  * Copyright (C) 2021 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__ "hids_client.c"
39 
40 #include "btstack_config.h"
41 
42 #ifdef ENABLE_TESTING_SUPPORT
43 #include <stdio.h>
44 #endif
45 
46 #include <stdint.h>
47 #include <string.h>
48 
49 #include "ble/gatt-service/hids_client.h"
50 
51 #include "btstack_memory.h"
52 #include "ble/att_db.h"
53 #include "ble/core.h"
54 #include "ble/gatt_client.h"
55 #include "ble/sm.h"
56 #include "bluetooth_gatt.h"
57 #include "btstack_debug.h"
58 #include "btstack_event.h"
59 #include "btstack_run_loop.h"
60 #include "gap.h"
61 
62 #define HID_REPORT_MODE_REPORT_ID               3
63 #define HID_REPORT_MODE_REPORT_MAP_ID           4
64 #define HID_REPORT_MODE_HID_INFORMATION_ID      5
65 #define HID_REPORT_MODE_HID_CONTROL_POINT_ID    6
66 
67 static btstack_linked_list_t clients;
68 static uint16_t hids_cid_counter = 0;
69 
70 static uint8_t * hids_client_descriptor_storage;
71 static uint16_t  hids_client_descriptor_storage_len;
72 
73 static void handle_gatt_client_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
74 
75 #ifdef ENABLE_TESTING_SUPPORT
76 static char * hid_characteristic_name(uint16_t uuid){
77     switch (uuid){
78         case ORG_BLUETOOTH_CHARACTERISTIC_PROTOCOL_MODE:
79             return "PROTOCOL_MODE";
80 
81         case ORG_BLUETOOTH_CHARACTERISTIC_BOOT_KEYBOARD_INPUT_REPORT:
82             return "BOOT_KEYBOARD_INPUT_REPORT";
83 
84         case ORG_BLUETOOTH_CHARACTERISTIC_BOOT_MOUSE_INPUT_REPORT:
85             return "BOOT_MOUSE_INPUT_REPORT";
86 
87         case ORG_BLUETOOTH_CHARACTERISTIC_BOOT_KEYBOARD_OUTPUT_REPORT:
88             return "BOOT_KEYBOARD_OUTPUT_REPORT";
89 
90         case ORG_BLUETOOTH_CHARACTERISTIC_REPORT:
91             return "REPORT";
92 
93         case ORG_BLUETOOTH_CHARACTERISTIC_REPORT_MAP:
94             return "REPORT_MAP";
95 
96         case ORG_BLUETOOTH_CHARACTERISTIC_HID_INFORMATION:
97             return "HID_INFORMATION";
98 
99         case ORG_BLUETOOTH_CHARACTERISTIC_HID_CONTROL_POINT:
100             return "HID_CONTROL_POINT";
101         default:
102             return "UKNOWN";
103     }
104 }
105 #endif
106 
107 static hids_client_t * hids_get_client_for_con_handle(hci_con_handle_t con_handle){
108     btstack_linked_list_iterator_t it;
109     btstack_linked_list_iterator_init(&it, &clients);
110     while (btstack_linked_list_iterator_has_next(&it)){
111         hids_client_t * client = (hids_client_t *)btstack_linked_list_iterator_next(&it);
112         if (client->con_handle != con_handle) continue;
113         return client;
114     }
115     return NULL;
116 }
117 
118 static hids_client_t * hids_get_client_for_cid(uint16_t hids_cid){
119     btstack_linked_list_iterator_t it;
120     btstack_linked_list_iterator_init(&it, &clients);
121     while (btstack_linked_list_iterator_has_next(&it)){
122         hids_client_t * client = (hids_client_t *)btstack_linked_list_iterator_next(&it);
123         if (client->cid != hids_cid) continue;
124         return client;
125     }
126     return NULL;
127 }
128 
129 
130 // START Descriptor Storage Util
131 
132 static uint16_t hids_client_descriptor_storage_get_available_space(void){
133     // assumes all descriptors are back to back
134     uint16_t free_space = hids_client_descriptor_storage_len;
135     uint8_t i;
136 
137     btstack_linked_list_iterator_t it;
138     btstack_linked_list_iterator_init(&it, &clients);
139     while (btstack_linked_list_iterator_has_next(&it)){
140         hids_client_t * client = (hids_client_t *)btstack_linked_list_iterator_next(&it);
141         for (i = 0; i < client->num_instances; i++){
142             free_space -= client->services[i].hid_descriptor_len;
143         }
144     }
145     return free_space;
146 }
147 
148 static void hids_client_descriptor_storage_init(hids_client_t * client, uint8_t service_index){
149     client->services[service_index].hid_descriptor_len = 0;
150     client->services[service_index].hid_descriptor_max_len = hids_client_descriptor_storage_get_available_space();
151     client->services[service_index].hid_descriptor_offset = hids_client_descriptor_storage_len - client->services[service_index].hid_descriptor_max_len;
152 }
153 
154 static bool hids_client_descriptor_storage_store(hids_client_t * client, uint8_t service_index, uint8_t byte){
155     if (client->services[service_index].hid_descriptor_len >= client->services[service_index].hid_descriptor_max_len) return false;
156 
157     hids_client_descriptor_storage[client->services[service_index].hid_descriptor_offset + client->services[service_index].hid_descriptor_len] = byte;
158     client->services[service_index].hid_descriptor_len++;
159     return true;
160 }
161 
162 static void hids_client_descriptor_storage_delete(hids_client_t * client){
163     uint8_t service_index = 0;
164     uint16_t next_offset = 0;
165 
166     for (service_index = 0; service_index < client->num_instances; service_index++){
167         next_offset += client->services[service_index].hid_descriptor_offset + client->services[service_index].hid_descriptor_len;
168         client->services[service_index].hid_descriptor_len = 0;
169         client->services[service_index].hid_descriptor_offset = 0;
170     }
171 
172     memmove(&hids_client_descriptor_storage[client->services[0].hid_descriptor_offset],
173             &hids_client_descriptor_storage[next_offset],
174             hids_client_descriptor_storage_len - next_offset);
175 
176     uint8_t i;
177     btstack_linked_list_iterator_t it;
178     btstack_linked_list_iterator_init(&it, &clients);
179     while (btstack_linked_list_iterator_has_next(&it)){
180         hids_client_t * conn = (hids_client_t *)btstack_linked_list_iterator_next(&it);
181         for (i = 0; i < client->num_instances; i++){
182             if (conn->services[i].hid_descriptor_offset >= next_offset){
183                 conn->services[i].hid_descriptor_offset = next_offset;
184                 next_offset += conn->services[service_index].hid_descriptor_len;
185             }
186         }
187     }
188 }
189 
190 const uint8_t * hids_client_descriptor_storage_get_descriptor_data(uint16_t hids_cid, uint8_t service_index){
191     hids_client_t * client = hids_get_client_for_cid(hids_cid);
192     if (client == NULL){
193         return NULL;
194     }
195     if (service_index >= client->num_instances){
196         return NULL;
197     }
198     return &hids_client_descriptor_storage[client->services[service_index].hid_descriptor_offset];
199 }
200 
201 uint16_t hids_client_descriptor_storage_get_descriptor_len(uint16_t hids_cid, uint8_t service_index){
202     hids_client_t * client = hids_get_client_for_cid(hids_cid);
203     if (client == NULL){
204         return 0;
205     }
206     if (service_index >= client->num_instances){
207         return 0;
208     }
209     return client->services[service_index].hid_descriptor_len;
210 }
211 
212 // END Descriptor Storage Util
213 
214 static uint16_t hids_get_next_cid(void){
215     if (hids_cid_counter == 0xffff) {
216         hids_cid_counter = 1;
217     } else {
218         hids_cid_counter++;
219     }
220     return hids_cid_counter;
221 }
222 
223 static uint8_t find_report_index_for_value_handle(hids_client_t * client, uint16_t value_handle){
224     uint8_t i;
225     for (i = 0; i < client->num_reports; i++){
226         if (client->reports[i].value_handle == value_handle){
227             return i;
228         }
229     }
230     return HIDS_CLIENT_INVALID_REPORT_INDEX;
231 }
232 
233 static uint8_t find_external_report_index_for_value_handle(hids_client_t * client, uint16_t value_handle){
234     uint8_t i;
235     for (i = 0; i < client->num_external_reports; i++){
236         if (client->external_reports[i].value_handle == value_handle){
237             return i;
238         }
239     }
240     return HIDS_CLIENT_INVALID_REPORT_INDEX;
241 }
242 
243 static bool external_report_index_for_uuid_exists(hids_client_t * client, uint16_t uuid16){
244     uint8_t i;
245     for (i = 0; i < client->num_external_reports; i++){
246         if (client->external_reports[i].external_report_reference_uuid == uuid16){
247             return true;
248         }
249     }
250     return false;
251 }
252 
253 static uint8_t find_report_index_for_report_id(hids_client_t * client, uint8_t report_id){
254     uint8_t i;
255 
256     switch (client->protocol_mode){
257         case HID_PROTOCOL_MODE_BOOT:
258             for (i = 0; i < client->num_reports; i++){
259                 if (!client->reports[i].boot_report){
260                     continue;
261                 }
262                 if (client->reports[i].report_id == report_id){
263                     return i;
264                 }
265             }
266             break;
267 
268         default:
269             for (i = 0; i < client->num_reports; i++){
270                 if (client->reports[i].boot_report){
271                     continue;
272                 }
273                 if (client->reports[i].report_id == report_id){
274                     return i;
275                 }
276             }
277             break;
278     }
279     return HIDS_CLIENT_INVALID_REPORT_INDEX;
280 }
281 
282 
283 static uint8_t find_report_index_for_report_id_and_type(hids_client_t * client, uint8_t report_id, hid_report_type_t report_type){
284     uint8_t i;
285     switch (client->protocol_mode){
286         case HID_PROTOCOL_MODE_BOOT:
287             for (i = 0; i < client->num_reports; i++){
288                 if (!client->reports[i].boot_report){
289                     continue;
290                 }
291                 if ((client->reports[i].report_id == report_id) && (client->reports[i].report_type == report_type)){
292                     return i;
293                 }
294             }
295             break;
296 
297         default:
298             for (i = 0; i < client->num_reports; i++){
299                 if (client->reports[i].boot_report){
300                     continue;
301                 }
302                 if ((client->reports[i].report_id == report_id) && (client->reports[i].report_type == report_type)){
303                     return i;
304                 }
305             }
306             break;
307     }
308     return HIDS_CLIENT_INVALID_REPORT_INDEX;
309 }
310 
311 static uint8_t hids_client_add_characteristic(hids_client_t * client, gatt_client_characteristic_t * characteristic, uint8_t report_id, hid_report_type_t report_type, bool boot_report){
312 
313     uint8_t report_index = find_external_report_index_for_value_handle(client, characteristic->value_handle);
314     if (report_index != HIDS_CLIENT_INVALID_REPORT_INDEX){
315         return report_index;
316     }
317     report_index = client->num_reports;
318 
319     if (report_index < HIDS_CLIENT_NUM_REPORTS) {
320         client->reports[report_index].value_handle = characteristic->value_handle;
321         client->reports[report_index].end_handle = characteristic->end_handle;
322         client->reports[report_index].properties = characteristic->properties;
323 
324         client->reports[report_index].service_index = client->service_index;
325         client->reports[report_index].report_id = report_id;
326         client->reports[report_index].report_type = report_type;
327         client->reports[report_index].boot_report = boot_report;
328 
329         log_info("add index %d, id %d, type %d, value handle 0x%02x, properties 0x%02x", report_index, report_id, report_type, characteristic->value_handle, characteristic->properties);
330         client->num_reports++;
331         return report_index;
332     } else {
333         log_info("not enough storage, increase HIDS_CLIENT_NUM_REPORTS");
334         return HIDS_CLIENT_INVALID_REPORT_INDEX;
335     }
336 }
337 
338 static uint8_t hids_client_add_external_report(hids_client_t * client, gatt_client_characteristic_descriptor_t * characteristic_descriptor){
339     uint8_t report_index = client->num_external_reports;
340 
341     if (report_index < HIDS_CLIENT_NUM_REPORTS) {
342         client->external_reports[report_index].value_handle = characteristic_descriptor->handle;
343         client->external_reports[report_index].service_index = client->service_index;
344 
345         client->num_external_reports++;
346         log_info("add external index %d [%d], value handle 0x%02x", report_index, client->num_external_reports, characteristic_descriptor->handle);
347         return report_index;
348     } else {
349         log_info("not enough storage, increase HIDS_CLIENT_NUM_REPORTS");
350         return HIDS_CLIENT_INVALID_REPORT_INDEX;
351     }
352 }
353 
354 
355 static bool hid_clients_has_reports_in_report_mode(hids_client_t * client){
356     uint8_t i;
357     for (i = 0; i < client->num_reports; i++){
358         if (!client->reports[i].boot_report){
359             return true;
360         }
361     }
362     return false;
363 }
364 
365 static bool hid_clients_has_reports_in_boot_mode(hids_client_t * client){
366     uint8_t i;
367     for (i = 0; i < client->num_reports; i++){
368         if (client->reports[i].boot_report){
369             return true;
370         }
371     }
372     return false;
373 }
374 
375 static uint8_t hids_client_get_next_active_report_map_index(hids_client_t * client){
376     uint8_t i;
377     for (i = client->service_index; i < client->num_instances; i++){
378         if (client->services[i].report_map_value_handle != 0){
379             return i;
380         }
381     }
382     client->service_index = HIDS_CLIENT_INVALID_REPORT_INDEX;
383     return HIDS_CLIENT_INVALID_REPORT_INDEX;
384 }
385 
386 static bool hids_client_report_query_next_report_map(hids_client_t * client){
387     client->service_index++;
388     if (hids_client_get_next_active_report_map_index(client) != HIDS_CLIENT_INVALID_REPORT_INDEX){
389         client->state = HIDS_CLIENT_STATE_W2_READ_REPORT_MAP_HID_DESCRIPTOR;
390         return true;
391     }
392     return false;
393 }
394 
395 static bool hids_client_report_map_query_init(hids_client_t * client){
396     client->service_index = 0;
397 
398     if (hids_client_get_next_active_report_map_index(client) != HIDS_CLIENT_INVALID_REPORT_INDEX){
399         client->state = HIDS_CLIENT_STATE_W2_READ_REPORT_MAP_HID_DESCRIPTOR;
400         return true;
401     }
402     return false;
403 }
404 
405 static bool hids_client_report_query_next_report_map_uuid(hids_client_t * client){
406     client->report_index++;
407     if (client->report_index < client->num_external_reports){
408         client->state = HIDS_CLIENT_STATE_W2_REPORT_MAP_READ_EXTERNAL_REPORT_REFERENCE_UUID;
409         return true;
410     }
411     return false;
412 }
413 
414 static bool hids_client_report_map_uuid_query_init(hids_client_t * client){
415     client->report_index = 0;
416     if (client->num_external_reports > 0){
417         client->state = HIDS_CLIENT_STATE_W2_REPORT_MAP_READ_EXTERNAL_REPORT_REFERENCE_UUID;
418         return true;
419     }
420     return false;
421 }
422 
423 static uint8_t hids_client_get_next_report_index(hids_client_t * client){
424     uint8_t i;
425     uint8_t index = HIDS_CLIENT_INVALID_REPORT_INDEX;
426     switch (client->protocol_mode){
427         case HID_PROTOCOL_MODE_REPORT:
428             for (i = client->report_index; i < client->num_reports && (index == HIDS_CLIENT_INVALID_REPORT_INDEX); i++){
429                 hids_client_report_t report = client->reports[i];
430                 if (report.report_type == HID_REPORT_TYPE_RESERVED && report.report_id == HID_REPORT_MODE_REPORT_ID){
431                     index = i;
432                     client->service_index = report.service_index;
433                 }
434             }
435             break;
436         case HID_PROTOCOL_MODE_BOOT:
437             for (i = client->report_index; i < client->num_reports && (index == HIDS_CLIENT_INVALID_REPORT_INDEX); i++){
438                 hids_client_report_t report = client->reports[i];
439                 if (report.boot_report){
440                     index = i;
441                     client->service_index = report.service_index;
442                 }
443             }
444             break;
445         default:
446             break;
447     }
448 
449     client->report_index = index;
450     return index;
451 }
452 
453 static bool hids_client_report_query_next_report(hids_client_t * client){
454     client->report_index++;
455     if (hids_client_get_next_report_index(client) != HIDS_CLIENT_INVALID_REPORT_INDEX){
456         client->state = HIDS_CLIENT_STATE_W2_FIND_REPORT;
457         return true;
458     }
459     return false;
460 }
461 
462 static bool hids_client_report_query_init(hids_client_t * client){
463     client->report_index = 0;
464 
465     if (hids_client_get_next_report_index(client) != HIDS_CLIENT_INVALID_REPORT_INDEX){
466         client->state = HIDS_CLIENT_STATE_W2_FIND_REPORT;
467         return true;
468     }
469     return false;
470 }
471 
472 static uint8_t hids_client_get_next_notification_report_index(hids_client_t * client){
473     uint8_t i;
474     uint8_t index = HIDS_CLIENT_INVALID_REPORT_INDEX;
475 
476     switch (client->protocol_mode){
477         case HID_PROTOCOL_MODE_REPORT:
478             for (i = client->report_index; i < client->num_reports && (index == HIDS_CLIENT_INVALID_REPORT_INDEX); i++){
479                 hids_client_report_t report = client->reports[i];
480                 if (report.report_type != HID_REPORT_TYPE_INPUT){
481                     continue;
482                 }
483                 if (!report.boot_report){
484                     index = i;
485                 }
486             }
487             break;
488 
489         case HID_PROTOCOL_MODE_BOOT:
490             for (i = client->report_index; i < client->num_reports && (index == HIDS_CLIENT_INVALID_REPORT_INDEX); i++){
491                 hids_client_report_t report = client->reports[i];
492                 if (report.report_type != HID_REPORT_TYPE_INPUT){
493                     continue;
494                 }
495                 if (report.boot_report){
496                     index = i;
497                 }
498             }
499             break;
500 
501         default:
502             break;
503     }
504 
505     client->report_index = index;
506     return index;
507 }
508 
509 static bool hids_client_report_next_notification_report_index(hids_client_t * client){
510     client->report_index++;
511     if (hids_client_get_next_notification_report_index(client) != HIDS_CLIENT_INVALID_REPORT_INDEX){
512         client->state = HIDS_CLIENT_STATE_W2_ENABLE_INPUT_REPORTS;
513         return true;
514     }
515     return false;
516 }
517 
518 static bool hids_client_report_notifications_init(hids_client_t * client){
519     client->report_index = 0;
520 
521     if (hids_client_get_next_notification_report_index(client) != HIDS_CLIENT_INVALID_REPORT_INDEX){
522         client->state = HIDS_CLIENT_STATE_W2_ENABLE_INPUT_REPORTS;
523         return true;
524     }
525     return false;
526 }
527 
528 static hids_client_t * hids_create_client(hci_con_handle_t con_handle, uint16_t cid){
529     hids_client_t * client = btstack_memory_hids_client_get();
530     if (!client){
531         log_error("Not enough memory to create client");
532         return NULL;
533     }
534     client->state = HIDS_CLIENT_STATE_IDLE;
535     client->cid = cid;
536     client->con_handle = con_handle;
537 
538     btstack_linked_list_add(&clients, (btstack_linked_item_t *) client);
539     return client;
540 }
541 
542 static void hids_finalize_client(hids_client_t * client){
543     // stop listening
544     uint8_t i;
545     for (i = 0; i < client->num_reports; i++){
546         gatt_client_stop_listening_for_characteristic_value_updates(&client->reports[i].notification_listener);
547     }
548 
549     hids_client_descriptor_storage_delete(client);
550     btstack_linked_list_remove(&clients, (btstack_linked_item_t *) client);
551     btstack_memory_hids_client_free(client);
552 }
553 
554 
555 static void hids_emit_connection_established(hids_client_t * client, uint8_t status){
556     uint8_t event[8];
557     int pos = 0;
558     event[pos++] = HCI_EVENT_GATTSERVICE_META;
559     event[pos++] = sizeof(event) - 2;
560     event[pos++] = GATTSERVICE_SUBEVENT_HID_SERVICE_CONNECTED;
561     little_endian_store_16(event, pos, client->cid);
562     pos += 2;
563     event[pos++] = status;
564     event[pos++] = client->protocol_mode;
565     event[pos++] = client->num_instances;
566     (*client->client_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event));
567 }
568 
569 static void hids_client_setup_report_event(hids_client_t * client, uint8_t report_index, uint8_t *buffer, uint16_t report_len){
570     uint16_t pos = 0;
571     buffer[pos++] = HCI_EVENT_GATTSERVICE_META;
572     pos++;  // skip len
573     buffer[pos++] = GATTSERVICE_SUBEVENT_HID_REPORT;
574     little_endian_store_16(buffer, pos, client->cid);
575     pos += 2;
576     buffer[pos++] = client->reports[report_index].service_index;
577     buffer[pos++] = client->reports[report_index].report_id;
578     little_endian_store_16(buffer, pos, report_len + 1);
579     pos += 2;
580     buffer[pos++] = client->reports[report_index].report_id;
581     buffer[1] = pos + (report_len + 1) - 2;
582 
583 }
584 
585 static void hids_client_emit_hid_information_event(hids_client_t * client, const uint8_t *value, uint16_t value_len){
586     if (value_len != 4) return;
587 
588     uint8_t event[11];
589     int pos = 0;
590     event[pos++] = HCI_EVENT_GATTSERVICE_META;
591     event[pos++] = sizeof(event) - 2;
592     event[pos++] = GATTSERVICE_SUBEVENT_HID_INFORMATION;
593     little_endian_store_16(event, pos, client->cid);
594     pos += 2;
595     event[pos++] = client->service_index;
596 
597     memcpy(event+pos, value, 3);
598     pos += 3;
599     event[pos++] = (value[3] & 0x02) >> 1;
600     event[pos++] = value[3] & 0x01;
601 
602     (*client->client_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event));
603 }
604 
605 
606 static void handle_notification_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) {
607     UNUSED(packet_type);
608     UNUSED(channel);
609 
610     if (hci_event_packet_get_type(packet) != GATT_EVENT_NOTIFICATION) return;
611 
612     hids_client_t * client = hids_get_client_for_con_handle(gatt_event_notification_get_handle(packet));
613     btstack_assert(client != NULL);
614 
615     uint8_t report_index = find_report_index_for_value_handle(client, gatt_event_notification_get_value_handle(packet));
616     if (report_index == HIDS_CLIENT_INVALID_REPORT_INDEX){
617         return;
618     }
619 
620     uint8_t * in_place_event = &packet[-2];
621     hids_client_setup_report_event(client, report_index, in_place_event, gatt_event_notification_get_value_length(packet));
622     (*client->client_handler)(HCI_EVENT_GATTSERVICE_META, client->cid, in_place_event, size + 2);
623 }
624 
625 static void handle_report_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size) {
626     UNUSED(packet_type);
627     UNUSED(channel);
628 
629     if (hci_event_packet_get_type(packet) != GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT) return;
630 
631     hids_client_t * client = hids_get_client_for_con_handle(gatt_event_characteristic_value_query_result_get_handle(packet));
632     btstack_assert(client != NULL);
633 
634     if (client->state != HIDS_CLIENT_W4_GET_REPORT_RESULT){
635         return;
636     }
637     client->state = HIDS_CLIENT_STATE_CONNECTED;
638 
639     uint8_t report_index = find_report_index_for_value_handle(client, gatt_event_characteristic_value_query_result_get_value_handle(packet));
640     if (report_index == HIDS_CLIENT_INVALID_REPORT_INDEX){
641         return;
642     }
643 
644     uint8_t * in_place_event = &packet[-2];
645     hids_client_setup_report_event(client, report_index, in_place_event, gatt_event_characteristic_value_query_result_get_value_length(packet));
646     (*client->client_handler)(HCI_EVENT_GATTSERVICE_META, client->cid, in_place_event, size + 2);
647 }
648 
649 static void hids_run_for_client(hids_client_t * client){
650     uint8_t att_status;
651     gatt_client_service_t service;
652     gatt_client_characteristic_t characteristic;
653 
654     switch (client->state){
655         case HIDS_CLIENT_STATE_W2_QUERY_SERVICE:
656 #ifdef ENABLE_TESTING_SUPPORT
657             printf("\n\nQuery Services:\n");
658 #endif
659             client->state = HIDS_CLIENT_STATE_W4_SERVICE_RESULT;
660 
661             // result in GATT_EVENT_SERVICE_QUERY_RESULT
662             att_status = gatt_client_discover_primary_services_by_uuid16(handle_gatt_client_event, client->con_handle, ORG_BLUETOOTH_SERVICE_HUMAN_INTERFACE_DEVICE);
663             UNUSED(att_status);
664             break;
665 
666         case HIDS_CLIENT_STATE_W2_QUERY_CHARACTERISTIC:
667 #ifdef ENABLE_TESTING_SUPPORT
668             printf("\n\nQuery Characteristics of service %d:\n", client->service_index);
669 #endif
670             client->state = HIDS_CLIENT_STATE_W4_CHARACTERISTIC_RESULT;
671 
672             service.start_group_handle = client->services[client->service_index].start_handle;
673             service.end_group_handle = client->services[client->service_index].end_handle;
674 
675             // result in GATT_EVENT_CHARACTERISTIC_QUERY_RESULT
676             att_status = gatt_client_discover_characteristics_for_service(&handle_gatt_client_event, client->con_handle, &service);
677 
678             UNUSED(att_status);
679             break;
680 
681         case HIDS_CLIENT_STATE_W2_SET_BOOT_PROTOCOL_MODE:
682             att_status = gatt_client_write_value_of_characteristic_without_response(client->con_handle, client->protocol_mode_value_handle, 1, (uint8_t *)&client->required_protocol_mode);
683             UNUSED(att_status);
684 
685             client->protocol_mode = client->required_protocol_mode;
686             if (hids_client_report_query_init(client)){
687                 break;
688             }
689 
690             hids_emit_connection_established(client, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE);
691             hids_finalize_client(client);
692             break;
693 
694         case HIDS_CLIENT_STATE_W2_READ_REPORT_MAP_HID_DESCRIPTOR:
695 #ifdef ENABLE_TESTING_SUPPORT
696             printf("\n\nRead REPORT_MAP (Handle 0x%04X) HID Descriptor of service %d:\n", client->services[client->service_index].report_map_value_handle, client->service_index);
697 #endif
698             client->state = HIDS_CLIENT_STATE_W4_REPORT_MAP_HID_DESCRIPTOR;
699 
700             // result in GATT_EVENT_LONG_CHARACTERISTIC_VALUE_QUERY_RESULT
701             att_status = gatt_client_read_long_value_of_characteristic_using_value_handle(&handle_gatt_client_event, client->con_handle, client->services[client->service_index].report_map_value_handle);
702             UNUSED(att_status);
703             break;
704 
705         case HIDS_CLIENT_STATE_W2_REPORT_MAP_DISCOVER_CHARACTERISTIC_DESCRIPTORS:
706 #ifdef ENABLE_TESTING_SUPPORT
707             printf("\nDiscover REPORT_MAP (Handle 0x%04X) Characteristic Descriptors of service %d:\n", client->services[client->service_index].report_map_value_handle, client->service_index);
708 #endif
709             client->state = HIDS_CLIENT_STATE_W4_REPORT_MAP_CHARACTERISTIC_DESCRIPTORS_RESULT;
710 
711             characteristic.value_handle = client->services[client->service_index].report_map_value_handle;
712             characteristic.end_handle = client->services[client->service_index].report_map_end_handle;
713 
714             // result in GATT_EVENT_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT
715             att_status = gatt_client_discover_characteristic_descriptors(&handle_gatt_client_event, client->con_handle, &characteristic);
716             UNUSED(att_status);
717             break;
718 
719         case HIDS_CLIENT_STATE_W2_REPORT_MAP_READ_EXTERNAL_REPORT_REFERENCE_UUID:
720 #ifdef ENABLE_TESTING_SUPPORT
721             printf("\nRead external chr UUID (Handle 0x%04X) Characteristic Descriptors, service index %d:\n", client->external_reports[client->report_index].value_handle, client->service_index);
722 #endif
723             client->state = HIDS_CLIENT_STATE_W4_REPORT_MAP_EXTERNAL_REPORT_REFERENCE_UUID;
724 
725             // result in GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT
726             att_status = gatt_client_read_characteristic_descriptor_using_descriptor_handle(&handle_gatt_client_event, client->con_handle, client->external_reports[client->report_index].value_handle);
727             UNUSED(att_status);
728             break;
729 
730         case HIDS_CLIENT_STATE_W2_DISCOVER_EXTERNAL_REPORT_CHARACTERISTIC:
731  #ifdef ENABLE_TESTING_SUPPORT
732             printf("\nDiscover External Report Characteristic:\n");
733 #endif
734             client->state = HIDS_CLIENT_STATE_W4_EXTERNAL_REPORT_CHARACTERISTIC_RESULT;
735 
736             service.start_group_handle = 0x0001;
737             service.end_group_handle = 0xffff;
738 
739             // Result in GATT_EVENT_CHARACTERISTIC_QUERY_RESULT
740             att_status = gatt_client_discover_characteristics_for_service(&handle_gatt_client_event, client->con_handle, &service);
741             UNUSED(att_status);
742             break;
743 
744         case HIDS_CLIENT_STATE_W2_FIND_REPORT:
745 #ifdef ENABLE_TESTING_SUPPORT
746             printf("\nQuery Report Characteristic Descriptors [%d, %d, 0x%04X]:\n",
747                 client->report_index,
748                 client->reports[client->report_index].service_index,
749                 client->reports[client->report_index].value_handle);
750 #endif
751             client->state = HIDS_CLIENT_STATE_W4_REPORT_FOUND;
752             client->descriptor_handle = 0;
753 
754             characteristic.value_handle = client->reports[client->report_index].value_handle;
755             characteristic.end_handle = client->reports[client->report_index].end_handle;
756             characteristic.properties = client->reports[client->report_index].properties;
757 
758             // result in GATT_EVENT_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT
759             att_status = gatt_client_discover_characteristic_descriptors(&handle_gatt_client_event, client->con_handle, &characteristic);
760             UNUSED(att_status);
761             break;
762 
763         case HIDS_CLIENT_STATE_W2_READ_REPORT_ID_AND_TYPE:
764             client->state = HIDS_CLIENT_STATE_W4_REPORT_ID_AND_TYPE;
765 
766             // result in GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT
767             att_status = gatt_client_read_characteristic_descriptor_using_descriptor_handle(&handle_gatt_client_event, client->con_handle, client->descriptor_handle);
768             client->descriptor_handle = 0;
769             UNUSED(att_status);
770             break;
771 
772         case HIDS_CLIENT_STATE_W2_ENABLE_INPUT_REPORTS:
773             client->state = HIDS_CLIENT_STATE_W4_INPUT_REPORTS_ENABLED;
774 
775             characteristic.value_handle = client->reports[client->report_index].value_handle;
776             characteristic.end_handle = client->reports[client->report_index].end_handle;
777             characteristic.properties = client->reports[client->report_index].properties;
778 
779             // end of write marked in GATT_EVENT_QUERY_COMPLETE
780             att_status = gatt_client_write_client_characteristic_configuration(&handle_gatt_client_event, client->con_handle, &characteristic, GATT_CLIENT_CHARACTERISTICS_CONFIGURATION_NOTIFICATION);
781 
782             if (att_status != ERROR_CODE_SUCCESS){
783                 if (hids_client_report_next_notification_report_index(client)){
784                     hids_run_for_client(client);
785                     break;
786                 }
787                 client->state = HIDS_CLIENT_STATE_CONNECTED;
788                 hids_emit_connection_established(client, ERROR_CODE_SUCCESS);
789             } else {
790                 gatt_client_listen_for_characteristic_value_updates(
791                     &client->reports[client->report_index].notification_listener,
792                     &handle_notification_event, client->con_handle, &characteristic);
793 
794                 client->state = HIDS_CLIENT_STATE_CONNECTED;
795                 hids_emit_connection_established(client, ERROR_CODE_SUCCESS);
796             }
797             UNUSED(att_status);
798             break;
799 
800 
801         case HIDS_CLIENT_W2_SEND_REPORT:
802 
803 #ifdef ENABLE_TESTING_SUPPORT
804             printf("    Send report [%d, %d, 0x%04X]:\n",
805                 client->report_index,
806                 client->reports[client->report_index].service_index, client->reports[client->report_index].value_handle);
807 #endif
808 
809             client->state = HIDS_CLIENT_STATE_CONNECTED;
810 
811             att_status = gatt_client_write_value_of_characteristic_without_response(client->con_handle,
812                 client->reports[client->report_index].value_handle,
813                 client->report_len, (uint8_t *)client->report);
814             UNUSED(att_status);
815             break;
816 
817         case HIDS_CLIENT_W2_SEND_GET_REPORT:
818 #ifdef ENABLE_TESTING_SUPPORT
819             printf("    Get report [index %d, ID %d, Service %d, handle 0x%04X]:\n",
820                 client->report_index,
821                 client->reports[client->report_index].report_id,
822                 client->reports[client->report_index].service_index, client->reports[client->report_index].value_handle);
823 #endif
824 
825             client->state = HIDS_CLIENT_W4_GET_REPORT_RESULT;
826             // result in GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT
827             att_status = gatt_client_read_value_of_characteristic_using_value_handle(
828                 &handle_report_event,
829                 client->con_handle,
830                 client->reports[client->report_index].value_handle);
831             UNUSED(att_status);
832             break;
833 
834 #ifdef ENABLE_TESTING_SUPPORT
835         case HIDS_CLIENT_W2_READ_CHARACTERISTIC_CONFIGURATION:
836             client->state = HIDS_CLIENT_W4_CHARACTERISTIC_CONFIGURATION_RESULT;
837 
838             // result in GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT
839             att_status = gatt_client_read_value_of_characteristic_using_value_handle(
840                 &handle_gatt_client_event,
841                 client->con_handle,
842                 client->reports[client->report_index].ccc_handle);
843 
844             break;
845 #endif
846         case HIDS_CLIENT_W2_SEND_GET_HID_INFORMATION:
847             client->state = HIDS_CLIENT_W4_GET_HID_INFORMATION_RESULT;
848 
849             // result in GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT
850             att_status = gatt_client_read_value_of_characteristic_using_value_handle(
851                 &handle_gatt_client_event,
852                 client->con_handle,
853                 client->services[client->service_index].hid_information_value_handle);
854             break;
855         default:
856             break;
857     }
858 }
859 
860 static void handle_gatt_client_event(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
861     UNUSED(packet_type);
862     UNUSED(channel);
863     UNUSED(size);
864 
865     hids_client_t * client = NULL;
866     uint8_t att_status;
867     gatt_client_service_t service;
868     gatt_client_characteristic_t characteristic;
869     gatt_client_characteristic_descriptor_t characteristic_descriptor;
870 
871     // hids_client_report_t * boot_keyboard_report;
872     // hids_client_report_t * boot_mouse_report;
873     const uint8_t * characteristic_descriptor_value;
874     uint8_t i;
875     uint8_t report_index;
876 
877     const uint8_t * value;
878     uint16_t value_len;
879 
880     switch(hci_event_packet_get_type(packet)){
881         case GATT_EVENT_SERVICE_QUERY_RESULT:
882             client = hids_get_client_for_con_handle(gatt_event_service_query_result_get_handle(packet));
883             btstack_assert(client != NULL);
884 
885             if (client->state != HIDS_CLIENT_STATE_W4_SERVICE_RESULT) {
886                 hids_emit_connection_established(client, GATT_CLIENT_IN_WRONG_STATE);
887                 hids_finalize_client(client);
888                 break;
889             }
890 
891             if (client->num_instances < MAX_NUM_HID_SERVICES){
892                 uint8_t index = client->num_instances;
893                 gatt_event_service_query_result_get_service(packet, &service);
894                 client->services[index].start_handle = service.start_group_handle;
895                 client->services[index].end_handle = service.end_group_handle;
896                 client->num_instances++;
897 
898 #ifdef ENABLE_TESTING_SUPPORT
899                 printf("HID Service: start handle 0x%04X, end handle 0x%04X\n", client->services[index].start_handle, client->services[index].end_handle);
900 #endif
901                 hids_client_descriptor_storage_init(client, index);
902             }  else {
903                 log_info("%d hid services found, only first %d can be stored, increase MAX_NUM_HID_SERVICES", client->num_instances + 1, MAX_NUM_HID_SERVICES);
904             }
905             break;
906 
907         case GATT_EVENT_CHARACTERISTIC_QUERY_RESULT:
908             client = hids_get_client_for_con_handle(gatt_event_characteristic_query_result_get_handle(packet));
909             btstack_assert(client != NULL);
910             gatt_event_characteristic_query_result_get_characteristic(packet, &characteristic);
911 
912             report_index = HIDS_CLIENT_INVALID_REPORT_INDEX;
913             if (client->state == HIDS_CLIENT_STATE_W4_EXTERNAL_REPORT_CHARACTERISTIC_RESULT){
914                 if (!external_report_index_for_uuid_exists(client, characteristic.uuid16)){
915                     break;
916                 }
917             }
918 
919             switch (characteristic.uuid16){
920                 case ORG_BLUETOOTH_CHARACTERISTIC_PROTOCOL_MODE:
921                     client->protocol_mode_value_handle = characteristic.value_handle;
922                     break;
923 
924                 case ORG_BLUETOOTH_CHARACTERISTIC_BOOT_KEYBOARD_INPUT_REPORT:
925                     report_index = hids_client_add_characteristic(client, &characteristic, HID_BOOT_MODE_KEYBOARD_ID, HID_REPORT_TYPE_INPUT, true);
926                     break;
927 
928                 case ORG_BLUETOOTH_CHARACTERISTIC_BOOT_MOUSE_INPUT_REPORT:
929                     report_index = hids_client_add_characteristic(client, &characteristic, HID_BOOT_MODE_MOUSE_ID, HID_REPORT_TYPE_INPUT, true);
930                     break;
931 
932                 case ORG_BLUETOOTH_CHARACTERISTIC_BOOT_KEYBOARD_OUTPUT_REPORT:
933                     report_index = hids_client_add_characteristic(client, &characteristic, HID_BOOT_MODE_KEYBOARD_ID, HID_REPORT_TYPE_OUTPUT, true);
934                     break;
935 
936                 case ORG_BLUETOOTH_CHARACTERISTIC_REPORT:
937                     report_index = hids_client_add_characteristic(client, &characteristic, HID_REPORT_MODE_REPORT_ID, HID_REPORT_TYPE_RESERVED, false);
938                     break;
939 
940                 case ORG_BLUETOOTH_CHARACTERISTIC_REPORT_MAP:
941                     client->services[client->service_index].report_map_value_handle = characteristic.value_handle;
942                     client->services[client->service_index].report_map_end_handle = characteristic.end_handle;
943                     break;
944 
945                 case ORG_BLUETOOTH_CHARACTERISTIC_HID_INFORMATION:
946                     client->services[client->service_index].hid_information_value_handle = characteristic.value_handle;
947                     client->services[client->service_index].hid_information_end_handle = characteristic.end_handle;
948                     break;
949 
950                 case ORG_BLUETOOTH_CHARACTERISTIC_HID_CONTROL_POINT:
951                     client->services[client->service_index].control_point_value_handle = characteristic.value_handle;
952                     client->services[client->service_index].control_point_end_handle = characteristic.end_handle;
953                     break;
954 
955                 default:
956 #ifdef ENABLE_TESTING_SUPPORT
957                     printf("    TODO: Found external characteristic 0x%04X\n", characteristic.uuid16);
958 #endif
959                     return;
960             }
961 
962 #ifdef ENABLE_TESTING_SUPPORT
963             printf("HID Characteristic %s:  \n    Attribute Handle 0x%04X, Properties 0x%02X, Handle 0x%04X, UUID 0x%04X, service %d",
964                 hid_characteristic_name(characteristic.uuid16),
965                 characteristic.start_handle,
966                 characteristic.properties,
967                 characteristic.value_handle, characteristic.uuid16,
968                 client->service_index);
969 
970             if (report_index != HIDS_CLIENT_INVALID_REPORT_INDEX){
971                 printf(", report index 0x%02X", report_index);
972             }
973             printf("\n");
974 #endif
975             break;
976 
977         case GATT_EVENT_LONG_CHARACTERISTIC_VALUE_QUERY_RESULT:
978             // Map Report characteristic value == HID Descriptor
979             client = hids_get_client_for_con_handle(gatt_event_long_characteristic_value_query_result_get_handle(packet));
980             btstack_assert(client != NULL);
981 
982             value = gatt_event_long_characteristic_value_query_result_get_value(packet);
983             value_len = gatt_event_long_characteristic_value_query_result_get_value_length(packet);
984 
985 #ifdef ENABLE_TESTING_SUPPORT
986             // printf("Report Map HID Desc [%d] for service %d\n", descriptor_len, client->service_index);
987             printf_hexdump(value, value_len);
988 #endif
989             for (i = 0; i < value_len; i++){
990                 bool stored = hids_client_descriptor_storage_store(client, client->service_index, value[i]);
991                 if (!stored){
992                     client->services[client->service_index].hid_descriptor_status = ERROR_CODE_MEMORY_CAPACITY_EXCEEDED;
993                     break;
994                 }
995             }
996             break;
997 
998         case GATT_EVENT_ALL_CHARACTERISTIC_DESCRIPTORS_QUERY_RESULT:
999             client = hids_get_client_for_con_handle(gatt_event_all_characteristic_descriptors_query_result_get_handle(packet));
1000             btstack_assert(client != NULL);
1001             gatt_event_all_characteristic_descriptors_query_result_get_characteristic_descriptor(packet, &characteristic_descriptor);
1002 
1003             switch (client->state) {
1004                 case HIDS_CLIENT_STATE_W4_REPORT_MAP_CHARACTERISTIC_DESCRIPTORS_RESULT:
1005                     // setup for descriptor value query
1006                     if (characteristic_descriptor.uuid16 == ORG_BLUETOOTH_DESCRIPTOR_EXTERNAL_REPORT_REFERENCE){
1007                         report_index = hids_client_add_external_report(client, &characteristic_descriptor);
1008 
1009 #ifdef ENABLE_TESTING_SUPPORT
1010                         if (report_index != HIDS_CLIENT_INVALID_REPORT_INDEX){
1011                             printf("    External Report Reference Characteristic Descriptor: Handle 0x%04X, UUID 0x%04X, service %d, report index 0x%02X\n",
1012                                 characteristic_descriptor.handle,
1013                                 characteristic_descriptor.uuid16,
1014                                 client->service_index, report_index);
1015                         }
1016 #endif
1017                     }
1018                     break;
1019                 case HIDS_CLIENT_STATE_W4_REPORT_FOUND:
1020                     // setup for descriptor value query
1021                     if (characteristic_descriptor.uuid16 == ORG_BLUETOOTH_DESCRIPTOR_REPORT_REFERENCE){
1022                         client->descriptor_handle = characteristic_descriptor.handle;
1023 #ifdef ENABLE_TESTING_SUPPORT
1024                         printf("    Report Characteristic Report Reference Characteristic Descriptor:  Handle 0x%04X, UUID 0x%04X\n",
1025                             characteristic_descriptor.handle,
1026                             characteristic_descriptor.uuid16);
1027 #endif
1028                     }
1029 
1030 #ifdef ENABLE_TESTING_SUPPORT
1031                     if (characteristic_descriptor.uuid16 == ORG_BLUETOOTH_DESCRIPTOR_GATT_CLIENT_CHARACTERISTIC_CONFIGURATION){
1032                         client->reports[client->report_index].ccc_handle = characteristic_descriptor.handle;
1033                         printf("    Report Client Characteristic Configuration Descriptor: Handle 0x%04X, UUID 0x%04X\n",
1034                             characteristic_descriptor.handle,
1035                             characteristic_descriptor.uuid16);
1036                     }
1037 #endif
1038                     break;
1039 
1040                 default:
1041                     break;
1042             }
1043             break;
1044 
1045         case GATT_EVENT_CHARACTERISTIC_VALUE_QUERY_RESULT:
1046             client = hids_get_client_for_con_handle(gatt_event_characteristic_value_query_result_get_handle(packet));
1047             btstack_assert(client != NULL);
1048 
1049             value = gatt_event_characteristic_value_query_result_get_value(packet);
1050             value_len = gatt_event_characteristic_value_query_result_get_value_length(packet);
1051 
1052             switch (client->state){
1053 #ifdef ENABLE_TESTING_SUPPORT
1054                 case HIDS_CLIENT_W4_CHARACTERISTIC_CONFIGURATION_RESULT:
1055                     printf("    Received CCC value: ");
1056                     printf_hexdump(value,  value_len);
1057                     break;
1058 #endif
1059                 case HIDS_CLIENT_W4_GET_HID_INFORMATION_RESULT:
1060                     hids_client_emit_hid_information_event(client, value, value_len);
1061                     break;
1062 
1063                 default:
1064                     break;
1065             }
1066 
1067             break;
1068 
1069         case GATT_EVENT_CHARACTERISTIC_DESCRIPTOR_QUERY_RESULT:
1070             client = hids_get_client_for_con_handle(gatt_event_characteristic_descriptor_query_result_get_handle(packet));
1071             btstack_assert(client != NULL);
1072 
1073             if (gatt_event_characteristic_descriptor_query_result_get_descriptor_length(packet) != 2){
1074                 break;
1075             }
1076 
1077             characteristic_descriptor_value = gatt_event_characteristic_descriptor_query_result_get_descriptor(packet);
1078             switch (client->state) {
1079                 case HIDS_CLIENT_STATE_W4_REPORT_MAP_EXTERNAL_REPORT_REFERENCE_UUID:
1080                     // get external report characteristic uuid
1081                     report_index = find_external_report_index_for_value_handle(client, gatt_event_characteristic_descriptor_query_result_get_descriptor_handle(packet));
1082                     if (report_index != HIDS_CLIENT_INVALID_REPORT_INDEX){
1083                         client->external_reports[report_index].external_report_reference_uuid = little_endian_read_16(characteristic_descriptor_value, 0);
1084 #ifdef ENABLE_TESTING_SUPPORT
1085                         printf("    Update external_report_reference_uuid of report index 0x%02X, service index 0x%02X, UUID 0x%02X\n",
1086                             report_index, client->service_index, client->external_reports[report_index].external_report_reference_uuid);
1087 #endif
1088                     }
1089                     break;
1090 
1091                 case HIDS_CLIENT_STATE_W4_REPORT_ID_AND_TYPE:
1092 
1093                     if (client->report_index != HIDS_CLIENT_INVALID_REPORT_INDEX){
1094                         client->reports[client->report_index].report_id = characteristic_descriptor_value[0];
1095                         client->reports[client->report_index].report_type = (hid_report_type_t)characteristic_descriptor_value[1];
1096     #ifdef ENABLE_TESTING_SUPPORT
1097                         printf("    Update report ID and type [%d, %d] of report index 0x%02X, service index 0x%02X\n",
1098                             client->reports[client->report_index].report_id,
1099                             client->reports[client->report_index].report_type,
1100                             client->report_index, client->service_index);
1101     #endif
1102                     }
1103                     break;
1104 
1105                 default:
1106                     break;
1107             }
1108             break;
1109 
1110         case GATT_EVENT_QUERY_COMPLETE:
1111             client = hids_get_client_for_con_handle(gatt_event_query_complete_get_handle(packet));
1112             btstack_assert(client != NULL);
1113 
1114             att_status = gatt_event_query_complete_get_att_status(packet);
1115 
1116             switch (client->state){
1117                 case HIDS_CLIENT_STATE_W4_SERVICE_RESULT:
1118                     if (att_status != ATT_ERROR_SUCCESS){
1119                         hids_emit_connection_established(client, att_status);
1120                         hids_finalize_client(client);
1121                         break;
1122                     }
1123 
1124                     if (client->num_instances == 0){
1125                         hids_emit_connection_established(client, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE);
1126                         hids_finalize_client(client);
1127                         break;
1128                     }
1129 
1130                     client->service_index = 0;
1131                     client->state = HIDS_CLIENT_STATE_W2_QUERY_CHARACTERISTIC;
1132                     break;
1133 
1134                 case HIDS_CLIENT_STATE_W4_CHARACTERISTIC_RESULT:
1135                     if (att_status != ATT_ERROR_SUCCESS){
1136                         hids_emit_connection_established(client, att_status);
1137                         hids_finalize_client(client);
1138                         break;
1139                     }
1140 
1141                     if ((client->service_index + 1) < client->num_instances){
1142                         // discover characteristics of next service
1143                         client->service_index++;
1144                         client->state = HIDS_CLIENT_STATE_W2_QUERY_CHARACTERISTIC;
1145                         break;
1146                     }
1147 
1148                     switch (client->required_protocol_mode){
1149                         case HID_PROTOCOL_MODE_REPORT:
1150                             client->protocol_mode = HID_PROTOCOL_MODE_REPORT;
1151                             if (hid_clients_has_reports_in_report_mode(client)){
1152                                 client->protocol_mode = HID_PROTOCOL_MODE_REPORT;
1153                                 break;
1154                             }
1155                             hids_emit_connection_established(client, att_status);
1156                             hids_finalize_client(client);
1157                             return;
1158 
1159                         case HID_PROTOCOL_MODE_REPORT_WITH_FALLBACK_TO_BOOT:
1160                             if (hid_clients_has_reports_in_report_mode(client)){
1161                                 client->protocol_mode = HID_PROTOCOL_MODE_REPORT;
1162                                 break;
1163                             }
1164                             if (hid_clients_has_reports_in_boot_mode(client)){
1165                                 if (client->protocol_mode_value_handle != 0){
1166                                     client->state = HIDS_CLIENT_STATE_W2_SET_BOOT_PROTOCOL_MODE;
1167                                     break;
1168                                 }
1169                                 hids_emit_connection_established(client, att_status);
1170                                 hids_finalize_client(client);
1171                                 return;
1172                             }
1173                             break;
1174                         default:
1175                             if (hid_clients_has_reports_in_boot_mode(client)){
1176                                 if (client->protocol_mode_value_handle != 0){
1177                                     client->state = HIDS_CLIENT_STATE_W2_SET_BOOT_PROTOCOL_MODE;
1178                                     break;
1179                                 }
1180                                 hids_emit_connection_established(client, att_status);
1181                                 hids_finalize_client(client);
1182                                 return;
1183                             }
1184                             break;
1185                     }
1186 
1187                     if (client->state == HIDS_CLIENT_STATE_W2_SET_BOOT_PROTOCOL_MODE){
1188                         break;
1189                     }
1190 
1191                     // 1. we need to get HID Descriptor and
1192                     // 2. get external Report characteristics if referenced from Report Map
1193                     if (hids_client_report_map_query_init(client)){
1194                         break;
1195                     }
1196                     hids_emit_connection_established(client, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE);
1197                     hids_finalize_client(client);
1198                     break;
1199 
1200 
1201                 // HID descriptor found
1202                 case HIDS_CLIENT_STATE_W4_REPORT_MAP_HID_DESCRIPTOR:
1203                     if (att_status != ATT_ERROR_SUCCESS){
1204                         hids_emit_connection_established(client, att_status);
1205                         hids_finalize_client(client);
1206                         break;
1207                     }
1208                     client->state = HIDS_CLIENT_STATE_W2_REPORT_MAP_DISCOVER_CHARACTERISTIC_DESCRIPTORS;
1209                     break;
1210 
1211                 // found all descriptors, check if there is one with EXTERNAL_REPORT_REFERENCE
1212                 case HIDS_CLIENT_STATE_W4_REPORT_MAP_CHARACTERISTIC_DESCRIPTORS_RESULT:
1213                     // go for next report map
1214                     if (hids_client_report_query_next_report_map(client)){
1215                         break;
1216                     }
1217 
1218                     // read UUIDS for external characteristics
1219                     if (hids_client_report_map_uuid_query_init(client)){
1220                         break;
1221                     }
1222 
1223                     // discover characteristic descriptor for all Report characteristics,
1224                     // then read value of characteristic descriptor to get Report ID
1225                     if (hids_client_report_query_init(client)){
1226                         break;
1227                     }
1228 
1229                     hids_emit_connection_established(client, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE);
1230                     hids_finalize_client(client);
1231                     break;
1232 
1233                 case HIDS_CLIENT_STATE_W4_REPORT_MAP_EXTERNAL_REPORT_REFERENCE_UUID:
1234                     // go for next map report
1235                     if (hids_client_report_query_next_report_map_uuid(client)){
1236                         break;
1237                     }
1238 
1239                     // update external characteristics with correct value handle and end handle
1240                     client->state = HIDS_CLIENT_STATE_W2_DISCOVER_EXTERNAL_REPORT_CHARACTERISTIC;
1241                     break;
1242 
1243                 case HIDS_CLIENT_STATE_W4_EXTERNAL_REPORT_CHARACTERISTIC_RESULT:
1244                     // discover characteristic descriptor for all Report characteristics,
1245                     // then read value of characteristic descriptor to get Report ID
1246                     if (hids_client_report_query_init(client)){
1247                         break;
1248                     }
1249 
1250                     hids_emit_connection_established(client, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE);
1251                     hids_finalize_client(client);
1252                     break;
1253 
1254                 case HIDS_CLIENT_STATE_W4_REPORT_FOUND:
1255                     if (client->descriptor_handle != 0){
1256                         client->state = HIDS_CLIENT_STATE_W2_READ_REPORT_ID_AND_TYPE;
1257                         break;
1258                     }
1259 
1260                     // go for next report
1261                     if (hids_client_report_query_next_report(client)){
1262                         break;
1263                     }
1264                     client->state = HIDS_CLIENT_STATE_CONNECTED;
1265                     hids_emit_connection_established(client, ERROR_CODE_SUCCESS);
1266                     break;
1267 
1268                 case HIDS_CLIENT_STATE_W4_REPORT_ID_AND_TYPE:
1269                     // go for next report
1270                     if (hids_client_report_query_next_report(client)){
1271                         break;
1272                     }
1273                     if (hids_client_report_notifications_init(client)){
1274                         break;
1275                     }
1276                     client->state = HIDS_CLIENT_STATE_CONNECTED;
1277                     hids_emit_connection_established(client, ERROR_CODE_SUCCESS);
1278                     break;
1279 
1280                 case HIDS_CLIENT_STATE_W4_INPUT_REPORTS_ENABLED:
1281                     if (hids_client_report_next_notification_report_index(client)){
1282                         break;
1283                     }
1284                     client->state = HIDS_CLIENT_STATE_CONNECTED;
1285                     hids_emit_connection_established(client, ERROR_CODE_SUCCESS);
1286                     break;
1287 
1288 #ifdef ENABLE_TESTING_SUPPORT
1289                 case HIDS_CLIENT_W4_CHARACTERISTIC_CONFIGURATION_RESULT:
1290                     client->state = HIDS_CLIENT_W2_SEND_GET_REPORT;
1291                     break;
1292 #endif
1293 
1294                 case HIDS_CLIENT_W4_GET_HID_INFORMATION_RESULT:
1295                     client->state = HIDS_CLIENT_STATE_CONNECTED;
1296                     break;
1297 
1298                 default:
1299                     break;
1300             }
1301             break;
1302 
1303         default:
1304             break;
1305     }
1306 
1307     if (client != NULL){
1308         hids_run_for_client(client);
1309     }
1310 }
1311 
1312 uint8_t hids_client_connect(hci_con_handle_t con_handle, btstack_packet_handler_t packet_handler, hid_protocol_mode_t protocol_mode, uint16_t * hids_cid){
1313     btstack_assert(packet_handler != NULL);
1314 
1315     hids_client_t * client = hids_get_client_for_con_handle(con_handle);
1316     if (client != NULL){
1317         return ERROR_CODE_COMMAND_DISALLOWED;
1318     }
1319 
1320     uint16_t cid = hids_get_next_cid();
1321     if (hids_cid != NULL) {
1322         *hids_cid = cid;
1323     }
1324 
1325     client = hids_create_client(con_handle, cid);
1326     if (client == NULL) {
1327         return BTSTACK_MEMORY_ALLOC_FAILED;
1328     }
1329 
1330     client->required_protocol_mode = protocol_mode;
1331     client->client_handler = packet_handler;
1332     client->state = HIDS_CLIENT_STATE_W2_QUERY_SERVICE;
1333 
1334     hids_run_for_client(client);
1335     return ERROR_CODE_SUCCESS;
1336 }
1337 
1338 uint8_t hids_client_disconnect(uint16_t hids_cid){
1339     hids_client_t * client = hids_get_client_for_cid(hids_cid);
1340     if (client == NULL){
1341         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1342     }
1343     // finalize connection
1344     hids_finalize_client(client);
1345     return ERROR_CODE_SUCCESS;
1346 }
1347 
1348 uint8_t hids_client_send_report(uint16_t hids_cid, uint8_t report_id, const uint8_t * report, uint8_t report_len){
1349     hids_client_t * client = hids_get_client_for_cid(hids_cid);
1350     if (client == NULL){
1351         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1352     }
1353 
1354     if (client->state != HIDS_CLIENT_STATE_CONNECTED) {
1355         return ERROR_CODE_COMMAND_DISALLOWED;
1356     }
1357 
1358     uint8_t report_index = find_report_index_for_report_id_and_type(client, report_id, HID_REPORT_TYPE_OUTPUT);
1359 
1360     if (report_index == HIDS_CLIENT_INVALID_REPORT_INDEX){
1361         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1362     }
1363 
1364     uint16_t mtu;
1365     uint8_t status = gatt_client_get_mtu(client->con_handle, &mtu);
1366 
1367     if (status != ERROR_CODE_SUCCESS){
1368         return status;
1369     }
1370 
1371     if (mtu - 2 < report_len){
1372         return ERROR_CODE_PARAMETER_OUT_OF_MANDATORY_RANGE;
1373     }
1374 
1375     client->state = HIDS_CLIENT_W2_SEND_REPORT;
1376     client->report_index = report_index;
1377     client->report = report;
1378     client->report_len = report_len;
1379 
1380     hids_run_for_client(client);
1381     return ERROR_CODE_SUCCESS;
1382 }
1383 
1384 uint8_t hids_client_send_get_report(uint16_t hids_cid, uint8_t report_id){
1385     hids_client_t * client = hids_get_client_for_cid(hids_cid);
1386     if (client == NULL){
1387         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1388     }
1389 
1390     if (client->state != HIDS_CLIENT_STATE_CONNECTED) {
1391         return ERROR_CODE_COMMAND_DISALLOWED;
1392     }
1393 
1394     uint8_t report_index = find_report_index_for_report_id(client, report_id);
1395     if (report_index == HIDS_CLIENT_INVALID_REPORT_INDEX){
1396         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1397     }
1398 
1399     client->report_index = report_index;
1400 
1401 #ifdef ENABLE_TESTING_SUPPORT
1402     client->state = HIDS_CLIENT_W2_READ_CHARACTERISTIC_CONFIGURATION;
1403 #else
1404     client->state = HIDS_CLIENT_W2_SEND_GET_REPORT;
1405 #endif
1406     hids_run_for_client(client);
1407     return ERROR_CODE_SUCCESS;
1408 }
1409 
1410 
1411 uint8_t hids_client_get_hid_information(uint16_t hids_cid, uint8_t service_index){
1412     hids_client_t * client = hids_get_client_for_cid(hids_cid);
1413     if (client == NULL){
1414         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1415     }
1416 
1417     if (client->state != HIDS_CLIENT_STATE_CONNECTED) {
1418         return ERROR_CODE_COMMAND_DISALLOWED;
1419     }
1420 
1421     if (service_index >= client->num_instances){
1422         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1423     }
1424 
1425     client->service_index = service_index;
1426     client->state = HIDS_CLIENT_W2_SEND_GET_HID_INFORMATION;
1427     hids_run_for_client(client);
1428     return ERROR_CODE_SUCCESS;
1429 }
1430 
1431 void hids_client_init(uint8_t * hid_descriptor_storage, uint16_t hid_descriptor_storage_len){
1432     hids_client_descriptor_storage = hid_descriptor_storage;
1433     hids_client_descriptor_storage_len = hid_descriptor_storage_len;
1434 }
1435 
1436 void hids_client_deinit(void){}
1437