xref: /btstack/src/classic/avrcp.c (revision e6c9673776c7f85e24c76da7f4b1b83031102d2b)
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 uint8_t   attribute_value[1000];
92 static const unsigned int attribute_value_buffer_size = sizeof(attribute_value);
93 
94 
95 static const char * avrcp_subunit_type_name[] = {
96     "MONITOR", "AUDIO", "PRINTER", "DISC", "TAPE_RECORDER_PLAYER", "TUNER",
97     "CA", "CAMERA", "RESERVED", "PANEL", "BULLETIN_BOARD", "CAMERA_STORAGE",
98     "VENDOR_UNIQUE", "RESERVED_FOR_ALL_SUBUNIT_TYPES",
99     "EXTENDED_TO_NEXT_BYTE", "UNIT", "ERROR"
100 };
101 
102 const char * avrcp_subunit2str(uint16_t index){
103     if (index <= 11) return avrcp_subunit_type_name[index];
104     if (index >= 0x1C && index <= 0x1F) return avrcp_subunit_type_name[index - 0x10];
105     return avrcp_subunit_type_name[16];
106 }
107 
108 static const char * avrcp_event_name[] = {
109     "ERROR", "PLAYBACK_STATUS_CHANGED",
110     "TRACK_CHANGED", "TRACK_REACHED_END", "TRACK_REACHED_START",
111     "PLAYBACK_POS_CHANGED", "BATT_STATUS_CHANGED", "SYSTEM_STATUS_CHANGED",
112     "PLAYER_APPLICATION_SETTING_CHANGED", "NOW_PLAYING_CONTENT_CHANGED",
113     "AVAILABLE_PLAYERS_CHANGED", "ADDRESSED_PLAYER_CHANGED", "UIDS_CHANGED", "VOLUME_CHANGED"
114 };
115 const char * avrcp_event2str(uint16_t index){
116     if (index <= 0x0d) return avrcp_event_name[index];
117     return avrcp_event_name[0];
118 }
119 
120 static const char * avrcp_operation_name[] = {
121     "NOT SUPPORTED", // 0x3B
122     "SKIP", "NOT SUPPORTED", "NOT SUPPORTED", "NOT SUPPORTED", "NOT SUPPORTED",
123     "VOLUME_UP", "VOLUME_DOWN", "MUTE", "PLAY", "STOP", "PAUSE", "NOT SUPPORTED",
124     "REWIND", "FAST_FORWARD", "NOT SUPPORTED", "FORWARD", "BACKWARD" // 0x4C
125 };
126 const char * avrcp_operation2str(uint8_t index){
127     if (index >= 0x3B && index <= 0x4C) return avrcp_operation_name[index - 0x3B];
128     return avrcp_operation_name[0];
129 }
130 
131 static const char * avrcp_media_attribute_id_name[] = {
132     "NONE", "TITLE", "ARTIST", "ALBUM", "TRACK", "TOTAL TRACKS", "GENRE", "SONG LENGTH"
133 };
134 const char * avrcp_attribute2str(uint8_t index){
135     if (index >= 1 && index <= 7) return avrcp_media_attribute_id_name[index];
136     return avrcp_media_attribute_id_name[0];
137 }
138 
139 static const char * avrcp_play_status_name[] = {
140     "STOPPED", "PLAYING", "PAUSED", "FORWARD SEEK", "REVERSE SEEK",
141     "ERROR" // 0xFF
142 };
143 const char * avrcp_play_status2str(uint8_t index){
144     if (index >= 1 && index <= 4) return avrcp_play_status_name[index];
145     return avrcp_play_status_name[5];
146 }
147 
148 static const char * avrcp_ctype_name[] = {
149     "CONTROL",
150     "STATUS",
151     "SPECIFIC_INQUIRY",
152     "NOTIFY",
153     "GENERAL_INQUIRY",
154     "RESERVED5",
155     "RESERVED6",
156     "RESERVED7",
157     "NOT IMPLEMENTED IN REMOTE",
158     "ACCEPTED BY REMOTE",
159     "REJECTED BY REMOTE",
160     "IN_TRANSITION",
161     "IMPLEMENTED_STABLE",
162     "CHANGED_STABLE",
163     "RESERVED",
164     "INTERIM"
165 };
166 const char * avrcp_ctype2str(uint8_t index){
167     if (index < sizeof(avrcp_ctype_name)){
168         return avrcp_ctype_name[index];
169     }
170     return "NONE";
171 }
172 
173 static const char * avrcp_shuffle_mode_name[] = {
174     "SHUFFLE OFF",
175     "SHUFFLE ALL TRACKS",
176     "SHUFFLE GROUP"
177 };
178 
179 const char * avrcp_shuffle2str(uint8_t index){
180     if (index >= 1 && index <= 3) return avrcp_shuffle_mode_name[index-1];
181     return "NONE";
182 }
183 
184 static const char * avrcp_repeat_mode_name[] = {
185     "REPEAT OFF",
186     "REPEAT SINGLE TRACK",
187     "REPEAT ALL TRACKS",
188     "REPEAT GROUP"
189 };
190 
191 const char * avrcp_repeat2str(uint8_t index){
192     if (index >= 1 && index <= 4) return avrcp_repeat_mode_name[index-1];
193     return "NONE";
194 }
195 
196 uint8_t avrcp_cmd_opcode(uint8_t *packet, uint16_t size){
197     uint8_t cmd_opcode_index = 5;
198     if (cmd_opcode_index > size) return AVRCP_CMD_OPCODE_UNDEFINED;
199     return packet[cmd_opcode_index];
200 }
201 
202 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){
203     uint8_t* attribute;
204     de_create_sequence(service);
205 
206     // 0x0000 "Service Record Handle"
207     de_add_number(service, DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_RECORD_HANDLE);
208     de_add_number(service, DE_UINT, DE_SIZE_32, service_record_handle);
209 
210     // 0x0001 "Service Class ID List"
211     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST);
212     attribute = de_push_sequence(service);
213     {
214         if (controller){
215             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
216             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER);
217         } else {
218             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET);
219         }
220     }
221     de_pop_sequence(service, attribute);
222 
223     // 0x0004 "Protocol Descriptor List"
224     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST);
225     attribute = de_push_sequence(service);
226     {
227         uint8_t* l2cpProtocol = de_push_sequence(attribute);
228         {
229             de_add_number(l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
230             de_add_number(l2cpProtocol,  DE_UINT, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);
231         }
232         de_pop_sequence(attribute, l2cpProtocol);
233 
234         uint8_t* avctpProtocol = de_push_sequence(attribute);
235         {
236             de_add_number(avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // avctpProtocol_service
237             de_add_number(avctpProtocol,  DE_UINT, DE_SIZE_16,  0x0103);    // version
238         }
239         de_pop_sequence(attribute, avctpProtocol);
240     }
241     de_pop_sequence(service, attribute);
242 
243     // 0x0005 "Public Browse Group"
244     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BROWSE_GROUP_LIST); // public browse group
245     attribute = de_push_sequence(service);
246     {
247         de_add_number(attribute,  DE_UUID, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PUBLIC_BROWSE_ROOT);
248     }
249     de_pop_sequence(service, attribute);
250 
251     // 0x0009 "Bluetooth Profile Descriptor List"
252     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
253     attribute = de_push_sequence(service);
254     {
255         uint8_t *avrcProfile = de_push_sequence(attribute);
256         {
257             de_add_number(avrcProfile,  DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
258             de_add_number(avrcProfile,  DE_UINT, DE_SIZE_16, 0x0105);
259         }
260         de_pop_sequence(attribute, avrcProfile);
261     }
262     de_pop_sequence(service, attribute);
263 
264     // 0x000d "Additional Bluetooth Profile Descriptor List"
265     if (browsing){
266         de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS);
267         attribute = de_push_sequence(service);
268         {
269             uint8_t * des = de_push_sequence(attribute);
270             {
271                 uint8_t* browsing_l2cpProtocol = de_push_sequence(des);
272                 {
273                     de_add_number(browsing_l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
274                     de_add_number(browsing_l2cpProtocol,  DE_UINT, DE_SIZE_16, PSM_AVCTP_BROWSING);
275                 }
276                 de_pop_sequence(des, browsing_l2cpProtocol);
277 
278                 uint8_t* browsing_avctpProtocol = de_push_sequence(des);
279                 {
280                     de_add_number(browsing_avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // browsing_avctpProtocol_service
281                     de_add_number(browsing_avctpProtocol,  DE_UINT, DE_SIZE_16,  0x0103);    // version
282                 }
283                 de_pop_sequence(des, browsing_avctpProtocol);
284             }
285             de_pop_sequence(attribute, des);
286         }
287         de_pop_sequence(service, attribute);
288     }
289 
290 
291     // 0x0100 "Service Name"
292     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0100);
293     if (service_name){
294         de_add_data(service,  DE_STRING, strlen(service_name), (uint8_t *) service_name);
295     } else {
296         if (controller){
297             de_add_data(service,  DE_STRING, strlen(default_avrcp_controller_service_name), (uint8_t *) default_avrcp_controller_service_name);
298         } else {
299             de_add_data(service,  DE_STRING, strlen(default_avrcp_target_service_name), (uint8_t *) default_avrcp_target_service_name);
300         }
301     }
302 
303     // 0x0100 "Provider Name"
304     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0102);
305     if (service_provider_name){
306         de_add_data(service,  DE_STRING, strlen(service_provider_name), (uint8_t *) service_provider_name);
307     } else {
308         if (controller){
309             de_add_data(service,  DE_STRING, strlen(default_avrcp_controller_service_provider_name), (uint8_t *) default_avrcp_controller_service_provider_name);
310         } else {
311             de_add_data(service,  DE_STRING, strlen(default_avrcp_target_service_provider_name), (uint8_t *) default_avrcp_target_service_provider_name);
312         }
313     }
314 
315     // 0x0311 "Supported Features"
316     de_add_number(service, DE_UINT, DE_SIZE_16, 0x0311);
317     de_add_number(service, DE_UINT, DE_SIZE_16, supported_features);
318 }
319 
320 avrcp_connection_t * get_avrcp_connection_for_bd_addr(bd_addr_t addr, avrcp_context_t * context){
321     btstack_linked_list_iterator_t it;
322     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &context->connections);
323     while (btstack_linked_list_iterator_has_next(&it)){
324         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
325         if (memcmp(addr, connection->remote_addr, 6) != 0) continue;
326         return connection;
327     }
328     return NULL;
329 }
330 
331 avrcp_connection_t * get_avrcp_connection_for_l2cap_signaling_cid(uint16_t l2cap_cid, avrcp_context_t * context){
332     btstack_linked_list_iterator_t it;
333     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
334     while (btstack_linked_list_iterator_has_next(&it)){
335         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
336         if (connection->l2cap_signaling_cid != l2cap_cid) continue;
337         return connection;
338     }
339     return NULL;
340 }
341 
342 avrcp_connection_t * get_avrcp_connection_for_avrcp_cid(uint16_t avrcp_cid, avrcp_context_t * context){
343     btstack_linked_list_iterator_t it;
344     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
345     while (btstack_linked_list_iterator_has_next(&it)){
346         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
347         if (connection->avrcp_cid != avrcp_cid) continue;
348         return connection;
349     }
350     return NULL;
351 }
352 
353 void avrcp_request_can_send_now(avrcp_connection_t * connection, uint16_t l2cap_cid){
354     connection->wait_to_send = 1;
355     l2cap_request_can_send_now_event(l2cap_cid);
356 }
357 
358 
359 uint16_t avrcp_get_next_cid(void){
360     avrcp_cid_counter++;
361     if (avrcp_cid_counter == 0){
362         avrcp_cid_counter = 1;
363     }
364     return avrcp_cid_counter;
365 }
366 
367 static avrcp_connection_t * avrcp_create_connection(bd_addr_t remote_addr, avrcp_context_t * context){
368     avrcp_connection_t * connection = btstack_memory_avrcp_connection_get();
369     if (!connection){
370         log_error("avrcp: not enough memory to create connection");
371         return NULL;
372     }
373     memset(connection, 0, sizeof(avrcp_connection_t));
374     connection->state = AVCTP_CONNECTION_IDLE;
375     connection->transaction_label = 0xFF;
376     connection->avrcp_cid = avrcp_get_next_cid();
377     memcpy(connection->remote_addr, remote_addr, 6);
378     btstack_linked_list_add(&context->connections, (btstack_linked_item_t *) connection);
379     return connection;
380 }
381 
382 
383 void avrcp_emit_connection_established(btstack_packet_handler_t callback, uint16_t avrcp_cid, bd_addr_t addr, uint8_t status){
384     if (!callback) return;
385     uint8_t event[12];
386     int pos = 0;
387     event[pos++] = HCI_EVENT_AVRCP_META;
388     event[pos++] = sizeof(event) - 2;
389     event[pos++] = AVRCP_SUBEVENT_CONNECTION_ESTABLISHED;
390     event[pos++] = status;
391     reverse_bd_addr(addr,&event[pos]);
392     pos += 6;
393     little_endian_store_16(event, pos, avrcp_cid);
394     pos += 2;
395     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
396 }
397 
398 void avrcp_emit_connection_closed(btstack_packet_handler_t callback, uint16_t avrcp_cid){
399     if (!callback) return;
400     uint8_t event[5];
401     int pos = 0;
402     event[pos++] = HCI_EVENT_AVRCP_META;
403     event[pos++] = sizeof(event) - 2;
404     event[pos++] = AVRCP_SUBEVENT_CONNECTION_RELEASED;
405     little_endian_store_16(event, pos, avrcp_cid);
406     pos += 2;
407     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
408 }
409 
410 void avrcp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
411     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(sdp_query_context->avrcp_cid, sdp_query_context);
412     if (!connection) return;
413     if (connection->state != AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE) return;
414 
415     UNUSED(packet_type);
416     UNUSED(channel);
417     UNUSED(size);
418     uint8_t status;
419     des_iterator_t des_list_it;
420     des_iterator_t prot_it;
421     // uint32_t avdtp_remote_uuid    = 0;
422 
423     switch (hci_event_packet_get_type(packet)){
424         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
425             // Handle new SDP record
426             if (sdp_event_query_attribute_byte_get_record_id(packet) != sdp_query_context->record_id) {
427                 sdp_query_context->record_id = sdp_event_query_attribute_byte_get_record_id(packet);
428                 sdp_query_context->parse_sdp_record = 0;
429                 // log_info("SDP Record: Nr: %d", record_id);
430             }
431 
432             if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
433                 attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
434 
435                 if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
436                     switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
437                         case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
438                             if (de_get_element_type(attribute_value) != DE_DES) break;
439                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
440                                 uint8_t * element = des_iterator_get_element(&des_list_it);
441                                 if (de_get_element_type(element) != DE_UUID) continue;
442                                 uint32_t uuid = de_get_uuid32(element);
443                                 switch (uuid){
444                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET:
445                                         if (sdp_query_context->role == AVRCP_CONTROLLER) {
446                                             sdp_query_context->parse_sdp_record = 1;
447                                             break;
448                                         }
449                                         break;
450                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL:
451                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER:
452                                         if (sdp_query_context->role == AVRCP_TARGET) {
453                                             sdp_query_context->parse_sdp_record = 1;
454                                             break;
455                                         }
456                                         break;
457                                     default:
458                                         break;
459                                 }
460                             }
461                             break;
462 
463                         case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
464                                 if (!sdp_query_context->parse_sdp_record) break;
465                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
466                                 for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
467                                     uint8_t       *des_element;
468                                     uint8_t       *element;
469                                     uint32_t       uuid;
470 
471                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
472 
473                                     des_element = des_iterator_get_element(&des_list_it);
474                                     des_iterator_init(&prot_it, des_element);
475                                     element = des_iterator_get_element(&prot_it);
476 
477                                     if (de_get_element_type(element) != DE_UUID) continue;
478 
479                                     uuid = de_get_uuid32(element);
480                                     switch (uuid){
481                                         case BLUETOOTH_PROTOCOL_L2CAP:
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_l2cap_psm);
485                                             break;
486                                         case BLUETOOTH_PROTOCOL_AVCTP:
487                                             if (!des_iterator_has_more(&prot_it)) continue;
488                                             des_iterator_next(&prot_it);
489                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_query_context->avrcp_version);
490                                             break;
491                                         default:
492                                             break;
493                                     }
494                                 }
495                             }
496                             break;
497                         case BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS: {
498                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
499                                 if (!sdp_query_context->parse_sdp_record) break;
500                                 if (de_get_element_type(attribute_value) != DE_DES) break;
501 
502                                 des_iterator_t des_list_0_it;
503                                 uint8_t       *element_0;
504 
505                                 des_iterator_init(&des_list_0_it, attribute_value);
506                                 element_0 = des_iterator_get_element(&des_list_0_it);
507 
508                                 for (des_iterator_init(&des_list_it, element_0); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
509                                     uint8_t       *des_element;
510                                     uint8_t       *element;
511                                     uint32_t       uuid;
512 
513                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
514 
515                                     des_element = des_iterator_get_element(&des_list_it);
516                                     des_iterator_init(&prot_it, des_element);
517                                     element = des_iterator_get_element(&prot_it);
518 
519                                     if (de_get_element_type(element) != DE_UUID) continue;
520 
521                                     uuid = de_get_uuid32(element);
522                                     switch (uuid){
523                                         case BLUETOOTH_PROTOCOL_L2CAP:
524                                             if (!des_iterator_has_more(&prot_it)) continue;
525                                             des_iterator_next(&prot_it);
526                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->browsing_l2cap_psm);
527                                             break;
528                                         case BLUETOOTH_PROTOCOL_AVCTP:
529                                             if (!des_iterator_has_more(&prot_it)) continue;
530                                             des_iterator_next(&prot_it);
531                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->browsing_version);
532                                             break;
533                                         default:
534                                             break;
535                                     }
536                                 }
537                             }
538                             break;
539                         default:
540                             break;
541                     }
542                 }
543             } else {
544                 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));
545             }
546             break;
547 
548         case SDP_EVENT_QUERY_COMPLETE:{
549             status = sdp_event_query_complete_get_status(packet);
550 
551             if (status != ERROR_CODE_SUCCESS){
552                 avrcp_emit_connection_established(sdp_query_context->avrcp_callback, connection->avrcp_cid, connection->remote_addr, status);
553                 btstack_linked_list_remove(&sdp_query_context->connections, (btstack_linked_item_t*) connection);
554                 btstack_memory_avrcp_connection_free(connection);
555                 log_info("AVRCP: SDP query failed with status 0x%02x.", status);
556                 break;
557             }
558 
559             if (!sdp_query_context->parse_sdp_record){
560                 connection->state = AVCTP_CONNECTION_IDLE;
561                 avrcp_emit_connection_established(sdp_query_context->avrcp_callback, connection->avrcp_cid, connection->remote_addr, SDP_SERVICE_NOT_FOUND);
562                 btstack_linked_list_remove(&sdp_query_context->connections, (btstack_linked_item_t*) connection);
563                 btstack_memory_avrcp_connection_free(connection);
564                 break;
565             }
566             // log_info("AVRCP Control PSM 0x%02x, Browsing PSM 0x%02x", sdp_query_context->avrcp_l2cap_psm, sdp_query_context->browsing_l2cap_psm);
567             connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
568             l2cap_create_channel(sdp_query_context->packet_handler, connection->remote_addr, sdp_query_context->avrcp_l2cap_psm, l2cap_max_mtu(), NULL);
569             break;
570         }
571     }
572 }
573 
574 void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avrcp_context_t * context){
575     UNUSED(channel);
576     UNUSED(size);
577     bd_addr_t event_addr;
578     uint16_t local_cid;
579     uint8_t  status;
580     avrcp_connection_t * connection = NULL;
581 
582     if (packet_type != HCI_EVENT_PACKET) return;
583 
584     switch (hci_event_packet_get_type(packet)) {
585         case HCI_EVENT_DISCONNECTION_COMPLETE:
586             avrcp_emit_connection_closed(context->avrcp_callback, 0);
587             break;
588         case L2CAP_EVENT_INCOMING_CONNECTION:
589             l2cap_event_incoming_connection_get_address(packet, event_addr);
590             local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
591             connection = avrcp_create_connection(event_addr, context);
592             if (!connection) {
593                 log_error("Failed to alloc connection structure");
594                 l2cap_decline_connection(local_cid);
595                 break;
596             }
597             connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
598             connection->l2cap_signaling_cid = local_cid;
599             log_info("L2CAP_EVENT_INCOMING_CONNECTION avrcp_cid 0x%02x, l2cap_signaling_cid 0x%02x", connection->avrcp_cid, connection->l2cap_signaling_cid);
600             l2cap_accept_connection(local_cid);
601             break;
602 
603         case L2CAP_EVENT_CHANNEL_OPENED:
604             l2cap_event_channel_opened_get_address(packet, event_addr);
605             status = l2cap_event_channel_opened_get_status(packet);
606             local_cid = l2cap_event_channel_opened_get_local_cid(packet);
607 
608             connection = get_avrcp_connection_for_bd_addr(event_addr, context);
609             if (!connection){
610                 log_error("Failed to alloc AVRCP connection structure");
611                 avrcp_emit_connection_established(context->avrcp_callback, connection->avrcp_cid, event_addr, BTSTACK_MEMORY_ALLOC_FAILED);
612                 l2cap_disconnect(local_cid, 0); // reason isn't used
613                 break;
614             }
615             if (status != ERROR_CODE_SUCCESS){
616                 log_info("L2CAP connection to connection %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
617                 avrcp_emit_connection_established(context->avrcp_callback, connection->avrcp_cid, event_addr, status);
618                 btstack_linked_list_remove(&context->connections, (btstack_linked_item_t*) connection);
619                 btstack_memory_avrcp_connection_free(connection);
620                 break;
621             }
622             connection->l2cap_signaling_cid = local_cid;
623             connection->song_length_ms = 0xFFFFFFFF;
624             connection->song_position_ms = 0xFFFFFFFF;
625             connection->playback_status = AVRCP_PLAYBACK_STATUS_ERROR;
626 
627             log_info("L2CAP_EVENT_CHANNEL_OPENED avrcp_cid 0x%02x, l2cap_signaling_cid 0x%02x", connection->avrcp_cid, connection->l2cap_signaling_cid);
628             connection->state = AVCTP_CONNECTION_OPENED;
629             avrcp_emit_connection_established(context->avrcp_callback, connection->avrcp_cid, event_addr, ERROR_CODE_SUCCESS);
630             break;
631 
632         case L2CAP_EVENT_CHANNEL_CLOSED:
633             // data: event (8), len(8), channel (16)
634             local_cid = l2cap_event_channel_closed_get_local_cid(packet);
635             connection = get_avrcp_connection_for_l2cap_signaling_cid(local_cid, context);
636             if (connection){
637                 avrcp_emit_connection_closed(context->avrcp_callback, connection->avrcp_cid);
638                 // free connection
639                 btstack_linked_list_remove(&context->connections, (btstack_linked_item_t*) connection);
640                 btstack_memory_avrcp_connection_free(connection);
641                 break;
642             }
643             break;
644         default:
645             break;
646     }
647 }
648 
649 uint8_t avrcp_connect(bd_addr_t bd_addr, avrcp_context_t * context, uint16_t * avrcp_cid){
650     avrcp_connection_t * connection = get_avrcp_connection_for_bd_addr(bd_addr, context);
651     if (connection){
652         return ERROR_CODE_COMMAND_DISALLOWED;
653     }
654     connection = avrcp_create_connection(bd_addr, context);
655     if (!connection){
656         log_error("avrcp: could not allocate connection struct.");
657         return BTSTACK_MEMORY_ALLOC_FAILED;
658     }
659 
660     if (!avrcp_cid) return L2CAP_LOCAL_CID_DOES_NOT_EXIST;
661 
662     *avrcp_cid = connection->avrcp_cid;
663     connection->state = AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE;
664 
665     context->avrcp_l2cap_psm = 0;
666     context->avrcp_version = 0;
667     context->avrcp_cid = connection->avrcp_cid;
668     connection->browsing_l2cap_psm = 0;
669     sdp_query_context = context;
670     return sdp_client_query_uuid16(&avrcp_handle_sdp_client_query_result, bd_addr, BLUETOOTH_PROTOCOL_AVCTP);
671 }
672