xref: /btstack/src/classic/avrcp.c (revision 88949f844376f979826afad7a30727a235ee4f0c)
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,
203     const char * service_name, const char * service_provider_name){
204     uint8_t* attribute;
205     de_create_sequence(service);
206 
207     // 0x0000 "Service Record Handle"
208     de_add_number(service, DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_RECORD_HANDLE);
209     de_add_number(service, DE_UINT, DE_SIZE_32, service_record_handle);
210 
211     // 0x0001 "Service Class ID List"
212     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST);
213     attribute = de_push_sequence(service);
214     {
215         if (controller){
216             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
217             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER);
218         } else {
219             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET);
220         }
221     }
222     de_pop_sequence(service, attribute);
223 
224     // 0x0004 "Protocol Descriptor List"
225     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST);
226     attribute = de_push_sequence(service);
227     {
228         uint8_t* l2cpProtocol = de_push_sequence(attribute);
229         {
230             de_add_number(l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
231             de_add_number(l2cpProtocol,  DE_UINT, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);
232         }
233         de_pop_sequence(attribute, l2cpProtocol);
234 
235         uint8_t* avctpProtocol = de_push_sequence(attribute);
236         {
237             de_add_number(avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // avctpProtocol_service
238             de_add_number(avctpProtocol,  DE_UINT, DE_SIZE_16,  0x0103);    // version
239         }
240         de_pop_sequence(attribute, avctpProtocol);
241     }
242     de_pop_sequence(service, attribute);
243 
244     // 0x0005 "Public Browse Group"
245     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BROWSE_GROUP_LIST); // public browse group
246     attribute = de_push_sequence(service);
247     {
248         de_add_number(attribute,  DE_UUID, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PUBLIC_BROWSE_ROOT);
249     }
250     de_pop_sequence(service, attribute);
251 
252     // 0x0009 "Bluetooth Profile Descriptor List"
253     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
254     attribute = de_push_sequence(service);
255     {
256         uint8_t *avrcProfile = de_push_sequence(attribute);
257         {
258             de_add_number(avrcProfile,  DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
259             de_add_number(avrcProfile,  DE_UINT, DE_SIZE_16, 0x0105);
260         }
261         de_pop_sequence(attribute, avrcProfile);
262     }
263     de_pop_sequence(service, attribute);
264 
265     // 0x000d "Additional Bluetooth Profile Descriptor List"
266     if (browsing){
267         de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS);
268         attribute = de_push_sequence(service);
269         {
270             uint8_t * des = de_push_sequence(attribute);
271             {
272                 uint8_t* browsing_l2cpProtocol = de_push_sequence(des);
273                 {
274                     de_add_number(browsing_l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
275                     de_add_number(browsing_l2cpProtocol,  DE_UINT, DE_SIZE_16, PSM_AVCTP_BROWSING);
276                 }
277                 de_pop_sequence(des, browsing_l2cpProtocol);
278 
279                 uint8_t* browsing_avctpProtocol = de_push_sequence(des);
280                 {
281                     de_add_number(browsing_avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // browsing_avctpProtocol_service
282                     de_add_number(browsing_avctpProtocol,  DE_UINT, DE_SIZE_16,  0x0103);    // version
283                 }
284                 de_pop_sequence(des, browsing_avctpProtocol);
285             }
286             de_pop_sequence(attribute, des);
287         }
288         de_pop_sequence(service, attribute);
289     }
290 
291 
292     // 0x0100 "Service Name"
293     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0100);
294     if (service_name){
295         de_add_data(service,  DE_STRING, strlen(service_name), (uint8_t *) service_name);
296     } else {
297         if (controller){
298             de_add_data(service,  DE_STRING, strlen(default_avrcp_controller_service_name), (uint8_t *) default_avrcp_controller_service_name);
299         } else {
300             de_add_data(service,  DE_STRING, strlen(default_avrcp_target_service_name), (uint8_t *) default_avrcp_target_service_name);
301         }
302     }
303 
304     // 0x0100 "Provider Name"
305     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0102);
306     if (service_provider_name){
307         de_add_data(service,  DE_STRING, strlen(service_provider_name), (uint8_t *) service_provider_name);
308     } else {
309         if (controller){
310             de_add_data(service,  DE_STRING, strlen(default_avrcp_controller_service_provider_name), (uint8_t *) default_avrcp_controller_service_provider_name);
311         } else {
312             de_add_data(service,  DE_STRING, strlen(default_avrcp_target_service_provider_name), (uint8_t *) default_avrcp_target_service_provider_name);
313         }
314     }
315 
316     // 0x0311 "Supported Features"
317     de_add_number(service, DE_UINT, DE_SIZE_16, 0x0311);
318     de_add_number(service, DE_UINT, DE_SIZE_16, supported_features);
319 }
320 
321 avrcp_connection_t * get_avrcp_connection_for_bd_addr(bd_addr_t addr, avrcp_context_t * context){
322     btstack_linked_list_iterator_t it;
323     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &context->connections);
324     while (btstack_linked_list_iterator_has_next(&it)){
325         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
326         if (memcmp(addr, connection->remote_addr, 6) != 0) continue;
327         return connection;
328     }
329     return NULL;
330 }
331 
332 avrcp_connection_t * get_avrcp_connection_for_l2cap_signaling_cid(uint16_t l2cap_cid, avrcp_context_t * context){
333     btstack_linked_list_iterator_t it;
334     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
335     while (btstack_linked_list_iterator_has_next(&it)){
336         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
337         if (connection->l2cap_signaling_cid != l2cap_cid) continue;
338         return connection;
339     }
340     return NULL;
341 }
342 
343 avrcp_connection_t * get_avrcp_connection_for_avrcp_cid(uint16_t avrcp_cid, avrcp_context_t * context){
344     btstack_linked_list_iterator_t it;
345     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
346     while (btstack_linked_list_iterator_has_next(&it)){
347         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
348         if (connection->avrcp_cid != avrcp_cid) continue;
349         return connection;
350     }
351     return NULL;
352 }
353 
354 void avrcp_request_can_send_now(avrcp_connection_t * connection, uint16_t l2cap_cid){
355     connection->wait_to_send = 1;
356     l2cap_request_can_send_now_event(l2cap_cid);
357 }
358 
359 
360 uint16_t avrcp_get_next_cid(void){
361     avrcp_cid_counter++;
362     if (avrcp_cid_counter == 0){
363         avrcp_cid_counter = 1;
364     }
365     return avrcp_cid_counter;
366 }
367 
368 static avrcp_connection_t * avrcp_create_connection(bd_addr_t remote_addr, avrcp_context_t * context){
369     avrcp_connection_t * connection = btstack_memory_avrcp_connection_get();
370     if (!connection){
371         log_error("avrcp: not enough memory to create connection");
372         return NULL;
373     }
374     connection->state = AVCTP_CONNECTION_IDLE;
375     connection->transaction_label = 0xFF;
376     connection->max_num_fragments = 0xFF;
377     connection->avrcp_cid = avrcp_get_next_cid();
378     memcpy(connection->remote_addr, remote_addr, 6);
379     btstack_linked_list_add(&context->connections, (btstack_linked_item_t *) connection);
380     return connection;
381 }
382 
383 static void avrcp_finalize_connection(avrcp_connection_t * connection, avrcp_context_t * context){
384     btstack_linked_list_remove(&context->connections, (btstack_linked_item_t*) connection);
385     btstack_memory_avrcp_connection_free(connection);
386 }
387 
388 void avrcp_emit_connection_established(btstack_packet_handler_t callback, uint16_t avrcp_cid, bd_addr_t addr, uint8_t status){
389     if (!callback) return;
390     uint8_t event[12];
391     int pos = 0;
392     event[pos++] = HCI_EVENT_AVRCP_META;
393     event[pos++] = sizeof(event) - 2;
394     event[pos++] = AVRCP_SUBEVENT_CONNECTION_ESTABLISHED;
395     event[pos++] = status;
396     reverse_bd_addr(addr,&event[pos]);
397     pos += 6;
398     little_endian_store_16(event, pos, avrcp_cid);
399     pos += 2;
400     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
401 }
402 
403 void avrcp_emit_connection_closed(btstack_packet_handler_t callback, uint16_t avrcp_cid){
404     if (!callback) return;
405     uint8_t event[5];
406     int pos = 0;
407     event[pos++] = HCI_EVENT_AVRCP_META;
408     event[pos++] = sizeof(event) - 2;
409     event[pos++] = AVRCP_SUBEVENT_CONNECTION_RELEASED;
410     little_endian_store_16(event, pos, avrcp_cid);
411     pos += 2;
412     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
413 }
414 
415 void avrcp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
416     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(sdp_query_context->avrcp_cid, sdp_query_context);
417     if (!connection) return;
418     if (connection->state != AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE) return;
419 
420     UNUSED(packet_type);
421     UNUSED(channel);
422     UNUSED(size);
423     uint8_t status;
424     des_iterator_t des_list_it;
425     des_iterator_t prot_it;
426     // uint32_t avdtp_remote_uuid    = 0;
427 
428     switch (hci_event_packet_get_type(packet)){
429         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
430             // Handle new SDP record
431             if (sdp_event_query_attribute_byte_get_record_id(packet) != sdp_query_context->record_id) {
432                 sdp_query_context->record_id = sdp_event_query_attribute_byte_get_record_id(packet);
433                 sdp_query_context->parse_sdp_record = 0;
434                 // log_info("SDP Record: Nr: %d", record_id);
435             }
436 
437             if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
438                 attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
439 
440                 if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
441                     switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
442                         case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
443                             if (de_get_element_type(attribute_value) != DE_DES) break;
444                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
445                                 uint8_t * element = des_iterator_get_element(&des_list_it);
446                                 if (de_get_element_type(element) != DE_UUID) continue;
447                                 uint32_t uuid = de_get_uuid32(element);
448                                 switch (uuid){
449                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET:
450                                         if (sdp_query_context->role == AVRCP_CONTROLLER) {
451                                             sdp_query_context->parse_sdp_record = 1;
452                                             break;
453                                         }
454                                         break;
455                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL:
456                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER:
457                                         if (sdp_query_context->role == AVRCP_TARGET) {
458                                             sdp_query_context->parse_sdp_record = 1;
459                                             break;
460                                         }
461                                         break;
462                                     default:
463                                         break;
464                                 }
465                             }
466                             break;
467 
468                         case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
469                                 if (!sdp_query_context->parse_sdp_record) break;
470                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
471                                 for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
472                                     uint8_t       *des_element;
473                                     uint8_t       *element;
474                                     uint32_t       uuid;
475 
476                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
477 
478                                     des_element = des_iterator_get_element(&des_list_it);
479                                     des_iterator_init(&prot_it, des_element);
480                                     element = des_iterator_get_element(&prot_it);
481 
482                                     if (de_get_element_type(element) != DE_UUID) continue;
483 
484                                     uuid = de_get_uuid32(element);
485                                     des_iterator_next(&prot_it);
486                                     switch (uuid){
487                                         case BLUETOOTH_PROTOCOL_L2CAP:
488                                             if (!des_iterator_has_more(&prot_it)) continue;
489                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_query_context->avrcp_l2cap_psm);
490                                             break;
491                                         case BLUETOOTH_PROTOCOL_AVCTP:
492                                             if (!des_iterator_has_more(&prot_it)) continue;
493                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_query_context->avrcp_version);
494                                             break;
495                                         default:
496                                             break;
497                                     }
498                                 }
499                             }
500                             break;
501                         case BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS: {
502                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
503                                 if (!sdp_query_context->parse_sdp_record) break;
504                                 if (de_get_element_type(attribute_value) != DE_DES) break;
505 
506                                 des_iterator_t des_list_0_it;
507                                 uint8_t       *element_0;
508 
509                                 des_iterator_init(&des_list_0_it, attribute_value);
510                                 element_0 = des_iterator_get_element(&des_list_0_it);
511 
512                                 for (des_iterator_init(&des_list_it, element_0); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
513                                     uint8_t       *des_element;
514                                     uint8_t       *element;
515                                     uint32_t       uuid;
516 
517                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
518 
519                                     des_element = des_iterator_get_element(&des_list_it);
520                                     des_iterator_init(&prot_it, des_element);
521                                     element = des_iterator_get_element(&prot_it);
522 
523                                     if (de_get_element_type(element) != DE_UUID) continue;
524 
525                                     uuid = de_get_uuid32(element);
526                                     des_iterator_next(&prot_it);
527                                     switch (uuid){
528                                         case BLUETOOTH_PROTOCOL_L2CAP:
529                                             if (!des_iterator_has_more(&prot_it)) continue;
530                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->browsing_l2cap_psm);
531                                             break;
532                                         case BLUETOOTH_PROTOCOL_AVCTP:
533                                             if (!des_iterator_has_more(&prot_it)) continue;
534                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->browsing_version);
535                                             break;
536                                         default:
537                                             break;
538                                     }
539                                 }
540                             }
541                             break;
542                         default:
543                             break;
544                     }
545                 }
546             } else {
547                 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));
548             }
549             break;
550 
551         case SDP_EVENT_QUERY_COMPLETE:{
552             status = sdp_event_query_complete_get_status(packet);
553 
554             if (status != ERROR_CODE_SUCCESS){
555                 log_info("AVRCP: SDP query failed with status 0x%02x.", status);
556                 avrcp_emit_connection_established(sdp_query_context->avrcp_callback, connection->avrcp_cid, connection->remote_addr, status);
557                 avrcp_finalize_connection(connection, sdp_query_context);
558                 break;
559             }
560 
561             if (!sdp_query_context->avrcp_l2cap_psm){
562                 connection->state = AVCTP_CONNECTION_IDLE;
563                 log_info("AVRCP: no suitable service found");
564                 avrcp_emit_connection_established(sdp_query_context->avrcp_callback, connection->avrcp_cid, connection->remote_addr, SDP_SERVICE_NOT_FOUND);
565                 avrcp_finalize_connection(connection, sdp_query_context);
566                 break;
567             }
568             connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
569             l2cap_create_channel(sdp_query_context->packet_handler, connection->remote_addr, sdp_query_context->avrcp_l2cap_psm, l2cap_max_mtu(), NULL);
570             break;
571         }
572     }
573 }
574 
575 void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avrcp_context_t * context){
576     UNUSED(channel);
577     UNUSED(size);
578     bd_addr_t event_addr;
579     uint16_t local_cid;
580     uint8_t  status;
581     avrcp_connection_t * connection = NULL;
582     uint16_t psm;
583 
584     if (packet_type != HCI_EVENT_PACKET) return;
585 
586     switch (hci_event_packet_get_type(packet)) {
587         case HCI_EVENT_DISCONNECTION_COMPLETE:
588             avrcp_emit_connection_closed(context->avrcp_callback, 0);
589             break;
590         case L2CAP_EVENT_INCOMING_CONNECTION:
591             l2cap_event_incoming_connection_get_address(packet, event_addr);
592             local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
593             connection = avrcp_create_connection(event_addr, context);
594             if (!connection) {
595                 log_error("Failed to alloc connection structure");
596                 l2cap_decline_connection(local_cid);
597                 break;
598             }
599 
600             psm = l2cap_event_incoming_connection_get_psm(packet);
601             if (psm == PSM_AVCTP){
602                 if (!connection->l2cap_signaling_cid){
603                     connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
604                     connection->l2cap_signaling_cid = local_cid;
605                     log_info("L2CAP_EVENT_INCOMING_CONNECTION avrcp_cid 0x%02x, l2cap_signaling_cid 0x%02x", connection->avrcp_cid, connection->l2cap_signaling_cid);
606                     l2cap_accept_connection(local_cid);
607                     break;
608                 }
609             }
610             log_info("L2CAP_EVENT_INCOMING_CONNECTION local_cid 0x%02x, psm 0x%2x, decline connection", local_cid, psm);
611             l2cap_decline_connection(local_cid);
612             break;
613 
614         case L2CAP_EVENT_CHANNEL_OPENED:
615             l2cap_event_channel_opened_get_address(packet, event_addr);
616             status = l2cap_event_channel_opened_get_status(packet);
617             local_cid = l2cap_event_channel_opened_get_local_cid(packet);
618 
619             connection = get_avrcp_connection_for_bd_addr(event_addr, context);
620             if (!connection){
621                 // TODO: validate if this cannot happen. If not,  drop disconnect call
622                 log_error("AVRCP connection lookup failed");
623                 l2cap_disconnect(local_cid, 0); // reason isn't used
624                 break;
625             }
626             if (status != ERROR_CODE_SUCCESS){
627                 log_info("L2CAP connection to connection %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
628                 avrcp_emit_connection_established(context->avrcp_callback, connection->avrcp_cid, event_addr, status);
629                 avrcp_finalize_connection(connection, context);
630                 break;
631             }
632 
633             psm = l2cap_event_channel_opened_get_psm(packet);
634             if (psm == PSM_AVCTP){
635                 connection->l2cap_signaling_cid = local_cid;
636                 connection->l2cap_mtu = l2cap_event_channel_opened_get_remote_mtu(packet);
637                 connection->song_length_ms = 0xFFFFFFFF;
638                 connection->song_position_ms = 0xFFFFFFFF;
639                 connection->playback_status = AVRCP_PLAYBACK_STATUS_ERROR;
640 
641                 log_info("L2CAP_EVENT_CHANNEL_OPENED avrcp_cid 0x%02x, l2cap_signaling_cid 0x%02x", connection->avrcp_cid, connection->l2cap_signaling_cid);
642                 connection->state = AVCTP_CONNECTION_OPENED;
643                 avrcp_emit_connection_established(context->avrcp_callback, connection->avrcp_cid, event_addr, ERROR_CODE_SUCCESS);
644             }
645             break;
646 
647         case L2CAP_EVENT_CHANNEL_CLOSED:
648             // data: event (8), len(8), channel (16)
649             local_cid = l2cap_event_channel_closed_get_local_cid(packet);
650             connection = get_avrcp_connection_for_l2cap_signaling_cid(local_cid, context);
651             if (connection){
652                 avrcp_emit_connection_closed(context->avrcp_callback, connection->avrcp_cid);
653                 avrcp_finalize_connection(connection, context);
654                 break;
655             }
656             break;
657         default:
658             break;
659     }
660 }
661 
662 uint8_t avrcp_connect(bd_addr_t bd_addr, avrcp_context_t * context, uint16_t * avrcp_cid){
663     avrcp_connection_t * connection = get_avrcp_connection_for_bd_addr(bd_addr, context);
664     if (connection){
665         return ERROR_CODE_COMMAND_DISALLOWED;
666     }
667     connection = avrcp_create_connection(bd_addr, context);
668     if (!connection){
669         log_error("avrcp: could not allocate connection struct.");
670         return BTSTACK_MEMORY_ALLOC_FAILED;
671     }
672 
673     if (avrcp_cid){
674         *avrcp_cid = connection->avrcp_cid;
675     }
676 
677     connection->state = AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE;
678 
679     context->avrcp_l2cap_psm = 0;
680     context->avrcp_version = 0;
681     context->avrcp_cid = connection->avrcp_cid;
682     connection->browsing_l2cap_psm = 0;
683     sdp_query_context = context;
684 
685     uint8_t status = sdp_client_query_uuid16(&avrcp_handle_sdp_client_query_result, bd_addr, BLUETOOTH_PROTOCOL_AVCTP);
686 
687     // free connection struct in case of SDP connection error
688     if (status){
689         log_info("AVRCP: SDP query failed with status 0x%02x.", status);
690         avrcp_finalize_connection(connection, context);
691     }
692 
693     return status;
694 }
695