xref: /btstack/src/classic/avrcp.c (revision 0fd69bb60e2392102d1f581f8edfa090a8968aac)
1 /*
2  * Copyright (C) 2016 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__ "avrcp.c"
39 
40 #include <stdint.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 
45 #include "btstack.h"
46 #include "classic/avrcp.h"
47 #include "classic/avrcp_controller.h"
48 
49 #define PSM_AVCTP                       BLUETOOTH_PROTOCOL_AVCTP
50 #define PSM_AVCTP_BROWSING              0x001b
51 
52 /*
53 Category 1: Player/Recorder
54 Category 2: Monitor/Amplifier
55 Category 3: Tuner
56 Category 4: Menu
57 */
58 
59 /* controller supported features
60 Bit 0 = Category 1
61 Bit 1 = Category 2
62 Bit 2 = Category 3
63 Bit 3 = Category 4
64 Bit 4-5 = RFA
65 Bit 6 = Supports browsing
66 Bit 7-15 = RFA
67 The bits for supported categories are set to 1. Others are set to 0.
68 */
69 
70 /* target supported features
71 Bit 0 = Category 1
72 Bit 1 = Category 2
73 Bit 2 = Category 3
74 Bit 3 = Category 4
75 Bit 4 = Player Application Settings. Bit 0 should be set for this bit to be set.
76 Bit 5 = Group Navigation. Bit 0 should be set for this bit to be set.
77 Bit 6 = Supports browsing*4
78 Bit 7 = Supports multiple media player applications
79 Bit 8-15 = RFA
80 The bits for supported categories are set to 1. Others are set to 0.
81 */
82 
83 static const char * default_avrcp_controller_service_name = "BTstack AVRCP Controller Service";
84 static const char * default_avrcp_controller_service_provider_name = "BTstack AVRCP Controller Service Provider";
85 static const char * default_avrcp_target_service_name = "BTstack AVRCP Target Service";
86 static const char * default_avrcp_target_service_provider_name = "BTstack AVRCP Target Service Provider";
87 
88 static uint16_t  avrcp_cid_counter = 0;
89 
90 static avrcp_context_t * sdp_query_context;
91 static int record_id = -1;
92 static uint8_t   attribute_value[1000];
93 static const unsigned int attribute_value_buffer_size = sizeof(attribute_value);
94 
95 static void avrcp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
96 
97 static const char * avrcp_subunit_type_name[] = {
98     "MONITOR", "AUDIO", "PRINTER", "DISC", "TAPE_RECORDER_PLAYER", "TUNER",
99     "CA", "CAMERA", "RESERVED", "PANEL", "BULLETIN_BOARD", "CAMERA_STORAGE",
100     "VENDOR_UNIQUE", "RESERVED_FOR_ALL_SUBUNIT_TYPES",
101     "EXTENDED_TO_NEXT_BYTE", "UNIT", "ERROR"
102 };
103 
104 const char * avrcp_subunit2str(uint16_t index){
105     if (index <= 11) return avrcp_subunit_type_name[index];
106     if (index >= 0x1C && index <= 0x1F) return avrcp_subunit_type_name[index - 0x10];
107     return avrcp_subunit_type_name[16];
108 }
109 
110 static const char * avrcp_event_name[] = {
111     "ERROR", "PLAYBACK_STATUS_CHANGED",
112     "TRACK_CHANGED", "TRACK_REACHED_END", "TRACK_REACHED_START",
113     "PLAYBACK_POS_CHANGED", "BATT_STATUS_CHANGED", "SYSTEM_STATUS_CHANGED",
114     "PLAYER_APPLICATION_SETTING_CHANGED", "NOW_PLAYING_CONTENT_CHANGED",
115     "AVAILABLE_PLAYERS_CHANGED", "ADDRESSED_PLAYER_CHANGED", "UIDS_CHANGED", "VOLUME_CHANGED"
116 };
117 const char * avrcp_event2str(uint16_t index){
118     if (index <= 0x0d) return avrcp_event_name[index];
119     return avrcp_event_name[0];
120 }
121 
122 static const char * avrcp_operation_name[] = {
123     "NOT SUPPORTED", // 0x3B
124     "SKIP", "NOT SUPPORTED", "NOT SUPPORTED", "NOT SUPPORTED", "NOT SUPPORTED",
125     "VOLUME_UP", "VOLUME_DOWN", "MUTE", "PLAY", "STOP", "PAUSE", "NOT SUPPORTED",
126     "REWIND", "FAST_FORWARD", "NOT SUPPORTED", "FORWARD", "BACKWARD" // 0x4C
127 };
128 const char * avrcp_operation2str(uint8_t index){
129     if (index >= 0x3B && index <= 0x4C) return avrcp_operation_name[index - 0x3B];
130     return avrcp_operation_name[0];
131 }
132 
133 static const char * avrcp_media_attribute_id_name[] = {
134     "NONE", "TITLE", "ARTIST", "ALBUM", "TRACK", "TOTAL TRACKS", "GENRE", "SONG LENGTH"
135 };
136 const char * avrcp_attribute2str(uint8_t index){
137     if (index >= 1 && index <= 7) return avrcp_media_attribute_id_name[index];
138     return avrcp_media_attribute_id_name[0];
139 }
140 
141 static const char * avrcp_play_status_name[] = {
142     "STOPPED", "PLAYING", "PAUSED", "FORWARD SEEK", "REVERSE SEEK",
143     "ERROR" // 0xFF
144 };
145 const char * avrcp_play_status2str(uint8_t index){
146     if (index >= 1 && index <= 4) return avrcp_play_status_name[index];
147     return avrcp_play_status_name[5];
148 }
149 
150 static const char * avrcp_ctype_name[] = {
151     "CONTROL",
152     "STATUS",
153     "SPECIFIC_INQUIRY",
154     "NOTIFY",
155     "GENERAL_INQUIRY",
156     "RESERVED5",
157     "RESERVED6",
158     "RESERVED7",
159     "NOT IMPLEMENTED IN REMOTE",
160     "ACCEPTED BY REMOTE",
161     "REJECTED BY REMOTE",
162     "IN_TRANSITION",
163     "IMPLEMENTED_STABLE",
164     "CHANGED_STABLE",
165     "RESERVED",
166     "INTERIM"
167 };
168 const char * avrcp_ctype2str(uint8_t index){
169     if (index < sizeof(avrcp_ctype_name)){
170         return avrcp_ctype_name[index];
171     }
172     return "NONE";
173 }
174 
175 static const char * avrcp_shuffle_mode_name[] = {
176     "SHUFFLE OFF",
177     "SHUFFLE ALL TRACKS",
178     "SHUFFLE GROUP"
179 };
180 
181 const char * avrcp_shuffle2str(uint8_t index){
182     if (index >= 1 && index <= 3) return avrcp_shuffle_mode_name[index-1];
183     return "NONE";
184 }
185 
186 static const char * avrcp_repeat_mode_name[] = {
187     "REPEAT OFF",
188     "REPEAT SINGLE TRACK",
189     "REPEAT ALL TRACKS",
190     "REPEAT GROUP"
191 };
192 
193 const char * avrcp_repeat2str(uint8_t index){
194     if (index >= 1 && index <= 4) return avrcp_repeat_mode_name[index-1];
195     return "NONE";
196 }
197 
198 uint8_t avrcp_cmd_opcode(uint8_t *packet, uint16_t size){
199     uint8_t cmd_opcode_index = 5;
200     if (cmd_opcode_index > size) return AVRCP_CMD_OPCODE_UNDEFINED;
201     return packet[cmd_opcode_index];
202 }
203 
204 void avrcp_create_sdp_record(uint8_t controller, uint8_t * service, uint32_t service_record_handle, uint8_t browsing, uint16_t supported_features, const char * service_name, const char * service_provider_name){
205     uint8_t* attribute;
206     de_create_sequence(service);
207 
208     // 0x0000 "Service Record Handle"
209     de_add_number(service, DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_RECORD_HANDLE);
210     de_add_number(service, DE_UINT, DE_SIZE_32, service_record_handle);
211 
212     // 0x0001 "Service Class ID List"
213     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST);
214     attribute = de_push_sequence(service);
215     {
216         if (controller){
217             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
218             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER);
219         } else {
220             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET);
221         }
222     }
223     de_pop_sequence(service, attribute);
224 
225     // 0x0004 "Protocol Descriptor List"
226     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST);
227     attribute = de_push_sequence(service);
228     {
229         uint8_t* l2cpProtocol = de_push_sequence(attribute);
230         {
231             de_add_number(l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
232             de_add_number(l2cpProtocol,  DE_UINT, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);
233         }
234         de_pop_sequence(attribute, l2cpProtocol);
235 
236         uint8_t* avctpProtocol = de_push_sequence(attribute);
237         {
238             de_add_number(avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // avctpProtocol_service
239             de_add_number(avctpProtocol,  DE_UINT, DE_SIZE_16,  0x0103);    // version
240         }
241         de_pop_sequence(attribute, avctpProtocol);
242     }
243     de_pop_sequence(service, attribute);
244 
245     // 0x0005 "Public Browse Group"
246     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BROWSE_GROUP_LIST); // public browse group
247     attribute = de_push_sequence(service);
248     {
249         de_add_number(attribute,  DE_UUID, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PUBLIC_BROWSE_ROOT);
250     }
251     de_pop_sequence(service, attribute);
252 
253     // 0x0009 "Bluetooth Profile Descriptor List"
254     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
255     attribute = de_push_sequence(service);
256     {
257         uint8_t *avrcProfile = de_push_sequence(attribute);
258         {
259             de_add_number(avrcProfile,  DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
260             de_add_number(avrcProfile,  DE_UINT, DE_SIZE_16, 0x0105);
261         }
262         de_pop_sequence(attribute, avrcProfile);
263     }
264     de_pop_sequence(service, attribute);
265 
266     // 0x000d "Additional Bluetooth Profile Descriptor List"
267     if (browsing){
268         de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS);
269         attribute = de_push_sequence(service);
270         {
271             uint8_t * des = de_push_sequence(attribute);
272             {
273                 uint8_t* browsing_l2cpProtocol = de_push_sequence(des);
274                 {
275                     de_add_number(browsing_l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
276                     de_add_number(browsing_l2cpProtocol,  DE_UINT, DE_SIZE_16, PSM_AVCTP_BROWSING);
277                 }
278                 de_pop_sequence(des, browsing_l2cpProtocol);
279 
280                 uint8_t* browsing_avctpProtocol = de_push_sequence(des);
281                 {
282                     de_add_number(browsing_avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // browsing_avctpProtocol_service
283                     de_add_number(browsing_avctpProtocol,  DE_UINT, DE_SIZE_16,  0x0103);    // version
284                 }
285                 de_pop_sequence(des, browsing_avctpProtocol);
286             }
287             de_pop_sequence(attribute, des);
288         }
289         de_pop_sequence(service, attribute);
290     }
291 
292 
293     // 0x0100 "Service Name"
294     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0100);
295     if (service_name){
296         de_add_data(service,  DE_STRING, strlen(service_name), (uint8_t *) service_name);
297     } else {
298         if (controller){
299             de_add_data(service,  DE_STRING, strlen(default_avrcp_controller_service_name), (uint8_t *) default_avrcp_controller_service_name);
300         } else {
301             de_add_data(service,  DE_STRING, strlen(default_avrcp_target_service_name), (uint8_t *) default_avrcp_target_service_name);
302         }
303     }
304 
305     // 0x0100 "Provider Name"
306     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0102);
307     if (service_provider_name){
308         de_add_data(service,  DE_STRING, strlen(service_provider_name), (uint8_t *) service_provider_name);
309     } else {
310         if (controller){
311             de_add_data(service,  DE_STRING, strlen(default_avrcp_controller_service_provider_name), (uint8_t *) default_avrcp_controller_service_provider_name);
312         } else {
313             de_add_data(service,  DE_STRING, strlen(default_avrcp_target_service_provider_name), (uint8_t *) default_avrcp_target_service_provider_name);
314         }
315     }
316 
317     // 0x0311 "Supported Features"
318     de_add_number(service, DE_UINT, DE_SIZE_16, 0x0311);
319     de_add_number(service, DE_UINT, DE_SIZE_16, supported_features);
320 }
321 
322 static avrcp_connection_t * get_avrcp_connection_for_bd_addr(bd_addr_t addr, avrcp_context_t * context){
323     btstack_linked_list_iterator_t it;
324     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &context->connections);
325     while (btstack_linked_list_iterator_has_next(&it)){
326         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
327         if (memcmp(addr, connection->remote_addr, 6) != 0) continue;
328         return connection;
329     }
330     return NULL;
331 }
332 
333 avrcp_connection_t * get_avrcp_connection_for_l2cap_signaling_cid(uint16_t l2cap_cid, avrcp_context_t * context){
334     btstack_linked_list_iterator_t it;
335     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
336     while (btstack_linked_list_iterator_has_next(&it)){
337         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
338         if (connection->l2cap_signaling_cid != l2cap_cid) continue;
339         return connection;
340     }
341     return NULL;
342 }
343 
344 avrcp_connection_t * get_avrcp_connection_for_avrcp_cid(uint16_t avrcp_cid, avrcp_context_t * context){
345     btstack_linked_list_iterator_t it;
346     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
347     while (btstack_linked_list_iterator_has_next(&it)){
348         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
349         if (connection->avrcp_cid != avrcp_cid) continue;
350         return connection;
351     }
352     return NULL;
353 }
354 
355 void avrcp_request_can_send_now(avrcp_connection_t * connection, uint16_t l2cap_cid){
356     connection->wait_to_send = 1;
357     l2cap_request_can_send_now_event(l2cap_cid);
358 }
359 
360 
361 static uint16_t avdtp_get_next_avrcp_cid(void){
362     avrcp_cid_counter++;
363     if (avrcp_cid_counter == 0){
364         avrcp_cid_counter = 1;
365     }
366     return avrcp_cid_counter;
367 }
368 
369 static avrcp_connection_t * avrcp_create_connection(bd_addr_t remote_addr, avrcp_context_t * context){
370     avrcp_connection_t * connection = btstack_memory_avrcp_connection_get();
371     memset(connection, 0, sizeof(avrcp_connection_t));
372     connection->state = AVCTP_CONNECTION_IDLE;
373     connection->transaction_label = 0xFF;
374     connection->avrcp_cid = avdtp_get_next_avrcp_cid();
375     memcpy(connection->remote_addr, remote_addr, 6);
376     btstack_linked_list_add(&context->connections, (btstack_linked_item_t *) connection);
377     return connection;
378 }
379 
380 
381 void avrcp_emit_connection_established(btstack_packet_handler_t callback, uint16_t avrcp_cid, bd_addr_t addr, uint8_t status){
382     if (!callback) return;
383     uint8_t event[12];
384     int pos = 0;
385     event[pos++] = HCI_EVENT_AVRCP_META;
386     event[pos++] = sizeof(event) - 2;
387     event[pos++] = AVRCP_SUBEVENT_CONNECTION_ESTABLISHED;
388     event[pos++] = status;
389     reverse_bd_addr(addr,&event[pos]);
390     pos += 6;
391     little_endian_store_16(event, pos, avrcp_cid);
392     pos += 2;
393     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
394 }
395 
396 void avrcp_emit_connection_closed(btstack_packet_handler_t callback, uint16_t avrcp_cid){
397     if (!callback) return;
398     uint8_t event[5];
399     int pos = 0;
400     event[pos++] = HCI_EVENT_AVRCP_META;
401     event[pos++] = sizeof(event) - 2;
402     event[pos++] = AVRCP_SUBEVENT_CONNECTION_RELEASED;
403     little_endian_store_16(event, pos, avrcp_cid);
404     pos += 2;
405     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
406 }
407 
408 static void avrcp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
409     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(sdp_query_context->avrcp_cid, sdp_query_context);
410     if (!connection) return;
411     if (connection->state != AVCTP_SIGNALING_W4_SDP_QUERY_COMPLETE) return;
412     UNUSED(packet_type);
413     UNUSED(channel);
414     UNUSED(size);
415 
416     des_iterator_t des_list_it;
417     des_iterator_t prot_it;
418     // uint32_t avdtp_remote_uuid    = 0;
419 
420     switch (hci_event_packet_get_type(packet)){
421         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
422             // Handle new SDP record
423             if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id) {
424                 record_id = sdp_event_query_attribute_byte_get_record_id(packet);
425                 // log_info("SDP Record: Nr: %d", record_id);
426             }
427 
428             if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
429                 attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
430 
431                 if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
432                     switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
433                         case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
434                             if (de_get_element_type(attribute_value) != DE_DES) break;
435                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
436                                 uint8_t * element = des_iterator_get_element(&des_list_it);
437                                 if (de_get_element_type(element) != DE_UUID) continue;
438                                 uint32_t uuid = de_get_uuid32(element);
439                                 switch (uuid){
440                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET:
441                                         if (sdp_query_context->role == AVRCP_CONTROLLER) {
442                                             sdp_query_context->role_supported = 1;
443                                             break;
444                                         }
445                                         break;
446                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL:
447                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER:
448                                         if (sdp_query_context->role == AVRCP_TARGET) {
449                                             sdp_query_context->role_supported = 1;
450                                             break;
451                                         }
452                                         break;
453                                     default:
454                                         break;
455                                 }
456                             }
457                             break;
458 
459                         case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
460                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
461                                 for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
462                                     uint8_t       *des_element;
463                                     uint8_t       *element;
464                                     uint32_t       uuid;
465 
466                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
467 
468                                     des_element = des_iterator_get_element(&des_list_it);
469                                     des_iterator_init(&prot_it, des_element);
470                                     element = des_iterator_get_element(&prot_it);
471 
472                                     if (de_get_element_type(element) != DE_UUID) continue;
473 
474                                     uuid = de_get_uuid32(element);
475                                     switch (uuid){
476                                         case BLUETOOTH_PROTOCOL_L2CAP:
477                                             if (!des_iterator_has_more(&prot_it)) continue;
478                                             des_iterator_next(&prot_it);
479                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_query_context->avrcp_l2cap_psm);
480                                             break;
481                                         case BLUETOOTH_PROTOCOL_AVCTP:
482                                             if (!des_iterator_has_more(&prot_it)) continue;
483                                             des_iterator_next(&prot_it);
484                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_query_context->avrcp_version);
485                                             break;
486                                         default:
487                                             break;
488                                     }
489                                 }
490                             }
491                             break;
492                         case BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS: {
493                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
494                                 if (de_get_element_type(attribute_value) != DE_DES) break;
495 
496                                 des_iterator_t des_list_0_it;
497                                 uint8_t       *element_0;
498 
499                                 des_iterator_init(&des_list_0_it, attribute_value);
500                                 element_0 = des_iterator_get_element(&des_list_0_it);
501 
502                                 for (des_iterator_init(&des_list_it, element_0); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
503                                     uint8_t       *des_element;
504                                     uint8_t       *element;
505                                     uint32_t       uuid;
506 
507                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
508 
509                                     des_element = des_iterator_get_element(&des_list_it);
510                                     des_iterator_init(&prot_it, des_element);
511                                     element = des_iterator_get_element(&prot_it);
512 
513                                     if (de_get_element_type(element) != DE_UUID) continue;
514 
515                                     uuid = de_get_uuid32(element);
516                                     switch (uuid){
517                                         case BLUETOOTH_PROTOCOL_L2CAP:
518                                             if (!des_iterator_has_more(&prot_it)) continue;
519                                             des_iterator_next(&prot_it);
520                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_query_context->avrcp_browsing_l2cap_psm);
521                                             break;
522                                         case BLUETOOTH_PROTOCOL_AVCTP:
523                                             if (!des_iterator_has_more(&prot_it)) continue;
524                                             des_iterator_next(&prot_it);
525                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_query_context->avrcp_browsing_version);
526                                             break;
527                                         default:
528                                             break;
529                                     }
530                                 }
531                             }
532                             break;
533                         default:
534                             break;
535                     }
536                 }
537             } else {
538                 log_error("SDP attribute value buffer size exceeded: available %d, required %d", attribute_value_buffer_size, sdp_event_query_attribute_byte_get_attribute_length(packet));
539             }
540             break;
541 
542         case SDP_EVENT_QUERY_COMPLETE:
543             log_info("General query done with status %d, role supported %d.\n", sdp_event_query_complete_get_status(packet), sdp_query_context->role_supported);
544             if (!sdp_query_context->role_supported || !sdp_query_context->avrcp_l2cap_psm){
545                 connection->state = AVCTP_CONNECTION_IDLE;
546                 avrcp_emit_connection_established(sdp_query_context->avrcp_callback, connection->avrcp_cid, connection->remote_addr, SDP_SERVICE_NOT_FOUND);
547                 break;
548             }
549             log_info("AVRCP Control PSM 0x%02x, Browsing PSM 0x%02x", sdp_query_context->avrcp_l2cap_psm, sdp_query_context->avrcp_browsing_l2cap_psm);
550             connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
551             l2cap_create_channel(sdp_query_context->packet_handler, connection->remote_addr, sdp_query_context->avrcp_l2cap_psm, l2cap_max_mtu(), NULL);
552             break;
553     }
554 }
555 
556 void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avrcp_context_t * context){
557     UNUSED(channel);
558     UNUSED(size);
559     bd_addr_t event_addr;
560     uint16_t local_cid;
561     uint8_t  status;
562     avrcp_connection_t * connection = NULL;
563 
564     if (packet_type != HCI_EVENT_PACKET) return;
565 
566     switch (hci_event_packet_get_type(packet)) {
567         case HCI_EVENT_DISCONNECTION_COMPLETE:
568             avrcp_emit_connection_closed(context->avrcp_callback, 0);
569             break;
570         case L2CAP_EVENT_INCOMING_CONNECTION:
571             l2cap_event_incoming_connection_get_address(packet, event_addr);
572             local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
573             connection = avrcp_create_connection(event_addr, context);
574             if (!connection) {
575                 log_error("Failed to alloc connection structure");
576                 l2cap_decline_connection(local_cid);
577                 break;
578             }
579             connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
580             connection->l2cap_signaling_cid = local_cid;
581             log_info("L2CAP_EVENT_INCOMING_CONNECTION avrcp_cid 0x%02x, l2cap_signaling_cid 0x%02x", connection->avrcp_cid, connection->l2cap_signaling_cid);
582             l2cap_accept_connection(local_cid);
583             break;
584 
585         case L2CAP_EVENT_CHANNEL_OPENED:
586             l2cap_event_channel_opened_get_address(packet, event_addr);
587             status = l2cap_event_channel_opened_get_status(packet);
588             local_cid = l2cap_event_channel_opened_get_local_cid(packet);
589 
590             connection = get_avrcp_connection_for_bd_addr(event_addr, context);
591             if (!connection){
592                 log_error("Failed to alloc AVRCP connection structure");
593                 avrcp_emit_connection_established(context->avrcp_callback, connection->avrcp_cid, event_addr, BTSTACK_MEMORY_ALLOC_FAILED);
594                 l2cap_disconnect(local_cid, 0); // reason isn't used
595                 break;
596             }
597             if (status != ERROR_CODE_SUCCESS){
598                 log_info("L2CAP connection to connection %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
599                 avrcp_emit_connection_established(context->avrcp_callback, connection->avrcp_cid, event_addr, status);
600                 btstack_linked_list_remove(&context->connections, (btstack_linked_item_t*) connection);
601                 btstack_memory_avrcp_connection_free(connection);
602                 break;
603             }
604             connection->l2cap_signaling_cid = local_cid;
605             log_info("L2CAP_EVENT_CHANNEL_OPENED avrcp_cid 0x%02x, l2cap_signaling_cid 0x%02x", connection->avrcp_cid, connection->l2cap_signaling_cid);
606             connection->state = AVCTP_CONNECTION_OPENED;
607             avrcp_emit_connection_established(context->avrcp_callback, connection->avrcp_cid, event_addr, ERROR_CODE_SUCCESS);
608             break;
609 
610         case L2CAP_EVENT_CHANNEL_CLOSED:
611             // data: event (8), len(8), channel (16)
612             printf("L2CAP_EVENT_CHANNEL_CLOSED \n");
613             local_cid = l2cap_event_channel_closed_get_local_cid(packet);
614             connection = get_avrcp_connection_for_l2cap_signaling_cid(local_cid, context);
615             if (connection){
616                 avrcp_emit_connection_closed(context->avrcp_callback, connection->avrcp_cid);
617                 // free connection
618                 btstack_linked_list_remove(&context->connections, (btstack_linked_item_t*) connection);
619                 btstack_memory_avrcp_connection_free(connection);
620                 break;
621             }
622             break;
623         default:
624             break;
625     }
626 }
627 
628 uint8_t avrcp_connect(bd_addr_t bd_addr, avrcp_context_t * context, uint16_t * avrcp_cid){
629     avrcp_connection_t * connection = get_avrcp_connection_for_bd_addr(bd_addr, context);
630     if (connection){
631         return ERROR_CODE_COMMAND_DISALLOWED;
632     }
633     connection = avrcp_create_connection(bd_addr, context);
634     if (!connection){
635         log_error("avrcp: could not allocate connection struct.");
636         return BTSTACK_MEMORY_ALLOC_FAILED;
637     }
638 
639     if (!avrcp_cid) return L2CAP_LOCAL_CID_DOES_NOT_EXIST;
640 
641     *avrcp_cid = connection->avrcp_cid;
642     connection->state = AVCTP_SIGNALING_W4_SDP_QUERY_COMPLETE;
643 
644     context->avrcp_l2cap_psm = 0;
645     context->avrcp_version = 0;
646     context->avrcp_cid = connection->avrcp_cid;
647 
648     sdp_query_context = context;
649 
650     sdp_client_query_uuid16(&avrcp_handle_sdp_client_query_result, bd_addr, BLUETOOTH_PROTOCOL_AVCTP);
651     return ERROR_CODE_SUCCESS;
652 }
653