xref: /btstack/src/classic/avrcp.c (revision 3c4cc6427fe05577c00b7d2593f58c7abcf9eab7)
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 static void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
53 
54 static const char * default_avrcp_controller_service_name = "BTstack AVRCP Controller Service";
55 static const char * default_avrcp_controller_service_provider_name = "BTstack AVRCP Controller Service Provider";
56 static const char * default_avrcp_target_service_name = "BTstack AVRCP Target Service";
57 static const char * default_avrcp_target_service_provider_name = "BTstack AVRCP Target Service Provider";
58 
59 static uint16_t  avrcp_cid_counter = 0;
60 
61 static avrcp_context_t * sdp_query_context;
62 static uint8_t   attribute_value[1000];
63 static const unsigned int attribute_value_buffer_size = sizeof(attribute_value);
64 
65 static btstack_linked_list_t connections;
66 static btstack_packet_handler_t avrcp_controller_packet_handler;
67 static btstack_packet_handler_t avrcp_target_packet_handler;
68 static int l2cap_service_registered = 0;
69 
70 static const char * avrcp_subunit_type_name[] = {
71     "MONITOR", "AUDIO", "PRINTER", "DISC", "TAPE_RECORDER_PLAYER", "TUNER",
72     "CA", "CAMERA", "RESERVED", "PANEL", "BULLETIN_BOARD", "CAMERA_STORAGE",
73     "VENDOR_UNIQUE", "RESERVED_FOR_ALL_SUBUNIT_TYPES",
74     "EXTENDED_TO_NEXT_BYTE", "UNIT", "ERROR"
75 };
76 
77 const char * avrcp_subunit2str(uint16_t index){
78     if (index <= 11) return avrcp_subunit_type_name[index];
79     if (index >= 0x1C && index <= 0x1F) return avrcp_subunit_type_name[index - 0x10];
80     return avrcp_subunit_type_name[16];
81 }
82 
83 static const char * avrcp_event_name[] = {
84     "ERROR", "PLAYBACK_STATUS_CHANGED",
85     "TRACK_CHANGED", "TRACK_REACHED_END", "TRACK_REACHED_START",
86     "PLAYBACK_POS_CHANGED", "BATT_STATUS_CHANGED", "SYSTEM_STATUS_CHANGED",
87     "PLAYER_APPLICATION_SETTING_CHANGED", "NOW_PLAYING_CONTENT_CHANGED",
88     "AVAILABLE_PLAYERS_CHANGED", "ADDRESSED_PLAYER_CHANGED", "UIDS_CHANGED", "VOLUME_CHANGED"
89 };
90 const char * avrcp_event2str(uint16_t index){
91     if (index <= 0x0d) return avrcp_event_name[index];
92     return avrcp_event_name[0];
93 }
94 
95 static const char * avrcp_operation_name[] = {
96     "NOT SUPPORTED", // 0x3B
97     "SKIP", "NOT SUPPORTED", "NOT SUPPORTED", "NOT SUPPORTED", "NOT SUPPORTED",
98     "VOLUME_UP", "VOLUME_DOWN", "MUTE", "PLAY", "STOP", "PAUSE", "NOT SUPPORTED",
99     "REWIND", "FAST_FORWARD", "NOT SUPPORTED", "FORWARD", "BACKWARD" // 0x4C
100 };
101 const char * avrcp_operation2str(uint8_t index){
102     if (index >= 0x3B && index <= 0x4C) return avrcp_operation_name[index - 0x3B];
103     return avrcp_operation_name[0];
104 }
105 
106 static const char * avrcp_media_attribute_id_name[] = {
107     "NONE", "TITLE", "ARTIST", "ALBUM", "TRACK", "TOTAL TRACKS", "GENRE", "SONG LENGTH"
108 };
109 const char * avrcp_attribute2str(uint8_t index){
110     if (index >= 1 && index <= 7) return avrcp_media_attribute_id_name[index];
111     return avrcp_media_attribute_id_name[0];
112 }
113 
114 static const char * avrcp_play_status_name[] = {
115     "STOPPED", "PLAYING", "PAUSED", "FORWARD SEEK", "REVERSE SEEK",
116     "ERROR" // 0xFF
117 };
118 const char * avrcp_play_status2str(uint8_t index){
119     if (index >= 1 && index <= 4) return avrcp_play_status_name[index];
120     return avrcp_play_status_name[5];
121 }
122 
123 static const char * avrcp_ctype_name[] = {
124     "CONTROL",
125     "STATUS",
126     "SPECIFIC_INQUIRY",
127     "NOTIFY",
128     "GENERAL_INQUIRY",
129     "RESERVED5",
130     "RESERVED6",
131     "RESERVED7",
132     "NOT IMPLEMENTED IN REMOTE",
133     "ACCEPTED BY REMOTE",
134     "REJECTED BY REMOTE",
135     "IN_TRANSITION",
136     "IMPLEMENTED_STABLE",
137     "CHANGED_STABLE",
138     "RESERVED",
139     "INTERIM"
140 };
141 const char * avrcp_ctype2str(uint8_t index){
142     if (index < sizeof(avrcp_ctype_name)){
143         return avrcp_ctype_name[index];
144     }
145     return "NONE";
146 }
147 
148 static const char * avrcp_shuffle_mode_name[] = {
149     "SHUFFLE OFF",
150     "SHUFFLE ALL TRACKS",
151     "SHUFFLE GROUP"
152 };
153 
154 const char * avrcp_shuffle2str(uint8_t index){
155     if (index >= 1 && index <= 3) return avrcp_shuffle_mode_name[index-1];
156     return "NONE";
157 }
158 
159 static const char * avrcp_repeat_mode_name[] = {
160     "REPEAT OFF",
161     "REPEAT SINGLE TRACK",
162     "REPEAT ALL TRACKS",
163     "REPEAT GROUP"
164 };
165 
166 const char * avrcp_repeat2str(uint8_t index){
167     if (index >= 1 && index <= 4) return avrcp_repeat_mode_name[index-1];
168     return "NONE";
169 }
170 
171 uint8_t avrcp_cmd_opcode(uint8_t *packet, uint16_t size){
172     uint8_t cmd_opcode_index = 5;
173     if (cmd_opcode_index > size) return AVRCP_CMD_OPCODE_UNDEFINED;
174     return packet[cmd_opcode_index];
175 }
176 
177 void avrcp_create_sdp_record(uint8_t controller, uint8_t * service, uint32_t service_record_handle, uint8_t browsing, uint16_t supported_features,
178     const char * service_name, const char * service_provider_name){
179     uint8_t* attribute;
180     de_create_sequence(service);
181 
182     // 0x0000 "Service Record Handle"
183     de_add_number(service, DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_RECORD_HANDLE);
184     de_add_number(service, DE_UINT, DE_SIZE_32, service_record_handle);
185 
186     // 0x0001 "Service Class ID List"
187     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST);
188     attribute = de_push_sequence(service);
189     {
190         if (controller){
191             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
192             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER);
193         } else {
194             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET);
195         }
196     }
197     de_pop_sequence(service, attribute);
198 
199     // 0x0004 "Protocol Descriptor List"
200     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST);
201     attribute = de_push_sequence(service);
202     {
203         uint8_t* l2cpProtocol = de_push_sequence(attribute);
204         {
205             de_add_number(l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
206             de_add_number(l2cpProtocol,  DE_UINT, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);
207         }
208         de_pop_sequence(attribute, l2cpProtocol);
209 
210         uint8_t* avctpProtocol = de_push_sequence(attribute);
211         {
212             de_add_number(avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // avctpProtocol_service
213             de_add_number(avctpProtocol,  DE_UINT, DE_SIZE_16,  0x0103);    // version
214         }
215         de_pop_sequence(attribute, avctpProtocol);
216     }
217     de_pop_sequence(service, attribute);
218 
219     // 0x0005 "Public Browse Group"
220     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BROWSE_GROUP_LIST); // public browse group
221     attribute = de_push_sequence(service);
222     {
223         de_add_number(attribute,  DE_UUID, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PUBLIC_BROWSE_ROOT);
224     }
225     de_pop_sequence(service, attribute);
226 
227     // 0x0009 "Bluetooth Profile Descriptor List"
228     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
229     attribute = de_push_sequence(service);
230     {
231         uint8_t *avrcProfile = de_push_sequence(attribute);
232         {
233             de_add_number(avrcProfile,  DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
234             de_add_number(avrcProfile,  DE_UINT, DE_SIZE_16, 0x0105);
235         }
236         de_pop_sequence(attribute, avrcProfile);
237     }
238     de_pop_sequence(service, attribute);
239 
240     // 0x000d "Additional Bluetooth Profile Descriptor List"
241     if (browsing){
242         de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS);
243         attribute = de_push_sequence(service);
244         {
245             uint8_t * des = de_push_sequence(attribute);
246             {
247                 uint8_t* browsing_l2cpProtocol = de_push_sequence(des);
248                 {
249                     de_add_number(browsing_l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
250                     de_add_number(browsing_l2cpProtocol,  DE_UINT, DE_SIZE_16, PSM_AVCTP_BROWSING);
251                 }
252                 de_pop_sequence(des, browsing_l2cpProtocol);
253 
254                 uint8_t* browsing_avctpProtocol = de_push_sequence(des);
255                 {
256                     de_add_number(browsing_avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // browsing_avctpProtocol_service
257                     de_add_number(browsing_avctpProtocol,  DE_UINT, DE_SIZE_16,  0x0103);    // version
258                 }
259                 de_pop_sequence(des, browsing_avctpProtocol);
260             }
261             de_pop_sequence(attribute, des);
262         }
263         de_pop_sequence(service, attribute);
264     }
265 
266 
267     // 0x0100 "Service Name"
268     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0100);
269     if (service_name){
270         de_add_data(service,  DE_STRING, strlen(service_name), (uint8_t *) service_name);
271     } else {
272         if (controller){
273             de_add_data(service,  DE_STRING, strlen(default_avrcp_controller_service_name), (uint8_t *) default_avrcp_controller_service_name);
274         } else {
275             de_add_data(service,  DE_STRING, strlen(default_avrcp_target_service_name), (uint8_t *) default_avrcp_target_service_name);
276         }
277     }
278 
279     // 0x0100 "Provider Name"
280     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0102);
281     if (service_provider_name){
282         de_add_data(service,  DE_STRING, strlen(service_provider_name), (uint8_t *) service_provider_name);
283     } else {
284         if (controller){
285             de_add_data(service,  DE_STRING, strlen(default_avrcp_controller_service_provider_name), (uint8_t *) default_avrcp_controller_service_provider_name);
286         } else {
287             de_add_data(service,  DE_STRING, strlen(default_avrcp_target_service_provider_name), (uint8_t *) default_avrcp_target_service_provider_name);
288         }
289     }
290 
291     // 0x0311 "Supported Features"
292     de_add_number(service, DE_UINT, DE_SIZE_16, 0x0311);
293     de_add_number(service, DE_UINT, DE_SIZE_16, supported_features);
294 }
295 
296 avrcp_connection_t * get_avrcp_connection_for_bd_addr(avrcp_role_t role, bd_addr_t addr){
297     btstack_linked_list_iterator_t it;
298     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &connections);
299     while (btstack_linked_list_iterator_has_next(&it)){
300         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
301         if (connection->role != role) continue;
302         if (memcmp(addr, connection->remote_addr, 6) != 0) continue;
303         return connection;
304     }
305     return NULL;
306 }
307 
308 avrcp_connection_t * get_avrcp_connection_for_l2cap_signaling_cid(avrcp_role_t role, uint16_t l2cap_cid){
309     btstack_linked_list_iterator_t it;
310     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &connections);
311     while (btstack_linked_list_iterator_has_next(&it)){
312         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
313         if (connection->role != role) continue;
314         if (connection->l2cap_signaling_cid != l2cap_cid) continue;
315         return connection;
316     }
317     return NULL;
318 }
319 
320 avrcp_connection_t * get_avrcp_connection_for_avrcp_cid(avrcp_role_t role, uint16_t avrcp_cid){
321     btstack_linked_list_iterator_t it;
322     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &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 (connection->role != role) continue;
326         if (connection->avrcp_cid != avrcp_cid) continue;
327         return connection;
328     }
329     return NULL;
330 }
331 
332 avrcp_connection_t * get_avrcp_connection_for_browsing_cid(avrcp_role_t role, uint16_t browsing_cid){
333     btstack_linked_list_iterator_t it;
334     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &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->role != role) continue;
338         if (connection->avrcp_browsing_cid != browsing_cid) continue;
339         return connection;
340     }
341     return NULL;
342 }
343 
344 avrcp_connection_t * get_avrcp_connection_for_browsing_l2cap_cid(avrcp_role_t role, uint16_t browsing_l2cap_cid){
345     btstack_linked_list_iterator_t it;
346     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &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->role != role) continue;
350         if (connection->browsing_connection &&  connection->browsing_connection->l2cap_browsing_cid != browsing_l2cap_cid) continue;
351         return connection;
352     }
353     return NULL;
354 }
355 
356 avrcp_browsing_connection_t * get_avrcp_browsing_connection_for_l2cap_cid(avrcp_role_t role, uint16_t l2cap_cid){
357     btstack_linked_list_iterator_t it;
358     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &connections);
359     while (btstack_linked_list_iterator_has_next(&it)){
360         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
361         if (connection->role != role) continue;
362         if (connection->browsing_connection && connection->browsing_connection->l2cap_browsing_cid != l2cap_cid) continue;
363         return connection->browsing_connection;
364     }
365     return NULL;
366 }
367 
368 void avrcp_request_can_send_now(avrcp_connection_t * connection, uint16_t l2cap_cid){
369     // printf("AVRCP: avrcp_request_can_send_now, role %d\n", connection->role);
370     connection->wait_to_send = 1;
371     l2cap_request_can_send_now_event(l2cap_cid);
372 }
373 
374 
375 uint16_t avrcp_get_next_cid(avrcp_role_t role){
376     do {
377         if (avrcp_cid_counter == 0xffff) {
378             avrcp_cid_counter = 1;
379         } else {
380             avrcp_cid_counter++;
381         }
382     } while (get_avrcp_connection_for_avrcp_cid(role, avrcp_cid_counter) !=  NULL) ;
383     return avrcp_cid_counter;
384 }
385 
386 
387 static avrcp_connection_t * avrcp_create_connection(avrcp_role_t role, bd_addr_t remote_addr){
388     avrcp_connection_t * connection = btstack_memory_avrcp_connection_get();
389     if (!connection){
390         log_error("Not enough memory to create connection for role %d", role);
391         return NULL;
392     }
393 
394     connection->state = AVCTP_CONNECTION_IDLE;
395     connection->role = role;
396     connection->transaction_label = 0xFF;
397     connection->max_num_fragments = 0xFF;
398     connection->avrcp_cid = avrcp_get_next_cid(role);
399     log_info("avrcp_create_connection, role %d, avrcp cid 0x%02x", role, connection->avrcp_cid);
400     memcpy(connection->remote_addr, remote_addr, 6);
401     btstack_linked_list_add(&connections, (btstack_linked_item_t *) connection);
402     return connection;
403 }
404 
405 static void avrcp_finalize_connection(avrcp_connection_t * connection){
406     btstack_linked_list_remove(&connections, (btstack_linked_item_t*) connection);
407     btstack_memory_avrcp_connection_free(connection);
408 }
409 
410 void avrcp_emit_connection_established(btstack_packet_handler_t callback, uint16_t avrcp_cid, bd_addr_t addr, uint8_t status){
411     if (!callback) return;
412     uint8_t event[12];
413     int pos = 0;
414     event[pos++] = HCI_EVENT_AVRCP_META;
415     event[pos++] = sizeof(event) - 2;
416     event[pos++] = AVRCP_SUBEVENT_CONNECTION_ESTABLISHED;
417     event[pos++] = status;
418     reverse_bd_addr(addr,&event[pos]);
419     pos += 6;
420     little_endian_store_16(event, pos, avrcp_cid);
421     pos += 2;
422     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
423 }
424 
425 void avrcp_emit_connection_closed(btstack_packet_handler_t callback, uint16_t avrcp_cid){
426     if (!callback) return;
427     uint8_t event[5];
428     int pos = 0;
429     event[pos++] = HCI_EVENT_AVRCP_META;
430     event[pos++] = sizeof(event) - 2;
431     event[pos++] = AVRCP_SUBEVENT_CONNECTION_RELEASED;
432     little_endian_store_16(event, pos, avrcp_cid);
433     pos += 2;
434     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
435 }
436 
437 void avrcp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
438     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(sdp_query_context->role, sdp_query_context->avrcp_cid);
439     if (!connection) return;
440     if (connection->state != AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE) return;
441 
442     UNUSED(packet_type);
443     UNUSED(channel);
444     UNUSED(size);
445     uint8_t status;
446     des_iterator_t des_list_it;
447     des_iterator_t prot_it;
448     // uint32_t avdtp_remote_uuid    = 0;
449 
450     switch (hci_event_packet_get_type(packet)){
451         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
452             // Handle new SDP record
453             if (sdp_event_query_attribute_byte_get_record_id(packet) != sdp_query_context->record_id) {
454                 sdp_query_context->record_id = sdp_event_query_attribute_byte_get_record_id(packet);
455                 sdp_query_context->parse_sdp_record = 0;
456                 // log_info("SDP Record: Nr: %d", record_id);
457             }
458 
459             if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
460                 attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
461 
462                 if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
463                     switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
464                         case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
465                             if (de_get_element_type(attribute_value) != DE_DES) break;
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 * element = des_iterator_get_element(&des_list_it);
468                                 if (de_get_element_type(element) != DE_UUID) continue;
469                                 uint32_t uuid = de_get_uuid32(element);
470                                 switch (uuid){
471                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET:
472                                         if (sdp_query_context->role == AVRCP_CONTROLLER) {
473                                             sdp_query_context->parse_sdp_record = 1;
474                                             break;
475                                         }
476                                         break;
477                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL:
478                                     case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER:
479                                         if (sdp_query_context->role == AVRCP_TARGET) {
480                                             sdp_query_context->parse_sdp_record = 1;
481                                             break;
482                                         }
483                                         break;
484                                     default:
485                                         break;
486                                 }
487                             }
488                             break;
489 
490                         case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
491                                 if (!sdp_query_context->parse_sdp_record) break;
492                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
493                                 for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
494                                     uint8_t       *des_element;
495                                     uint8_t       *element;
496                                     uint32_t       uuid;
497 
498                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
499 
500                                     des_element = des_iterator_get_element(&des_list_it);
501                                     des_iterator_init(&prot_it, des_element);
502                                     element = des_iterator_get_element(&prot_it);
503 
504                                     if (de_get_element_type(element) != DE_UUID) continue;
505 
506                                     uuid = de_get_uuid32(element);
507                                     des_iterator_next(&prot_it);
508                                     switch (uuid){
509                                         case BLUETOOTH_PROTOCOL_L2CAP:
510                                             if (!des_iterator_has_more(&prot_it)) continue;
511                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_query_context->avrcp_l2cap_psm);
512                                             break;
513                                         case BLUETOOTH_PROTOCOL_AVCTP:
514                                             if (!des_iterator_has_more(&prot_it)) continue;
515                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &sdp_query_context->avrcp_version);
516                                             break;
517                                         default:
518                                             break;
519                                     }
520                                 }
521                             }
522                             break;
523                         case BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS: {
524                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
525                                 if (!sdp_query_context->parse_sdp_record) break;
526                                 if (de_get_element_type(attribute_value) != DE_DES) break;
527 
528                                 des_iterator_t des_list_0_it;
529                                 uint8_t       *element_0;
530 
531                                 des_iterator_init(&des_list_0_it, attribute_value);
532                                 element_0 = des_iterator_get_element(&des_list_0_it);
533 
534                                 for (des_iterator_init(&des_list_it, element_0); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
535                                     uint8_t       *des_element;
536                                     uint8_t       *element;
537                                     uint32_t       uuid;
538 
539                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
540 
541                                     des_element = des_iterator_get_element(&des_list_it);
542                                     des_iterator_init(&prot_it, des_element);
543                                     element = des_iterator_get_element(&prot_it);
544 
545                                     if (de_get_element_type(element) != DE_UUID) continue;
546 
547                                     uuid = de_get_uuid32(element);
548                                     des_iterator_next(&prot_it);
549                                     switch (uuid){
550                                         case BLUETOOTH_PROTOCOL_L2CAP:
551                                             if (!des_iterator_has_more(&prot_it)) continue;
552                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->browsing_l2cap_psm);
553                                             break;
554                                         case BLUETOOTH_PROTOCOL_AVCTP:
555                                             if (!des_iterator_has_more(&prot_it)) continue;
556                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->browsing_version);
557                                             break;
558                                         default:
559                                             break;
560                                     }
561                                 }
562                             }
563                             break;
564                         default:
565                             break;
566                     }
567                 }
568             } else {
569                 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));
570             }
571             break;
572 
573         case SDP_EVENT_QUERY_COMPLETE:{
574             status = sdp_event_query_complete_get_status(packet);
575 
576             if (status != ERROR_CODE_SUCCESS){
577                 log_info("AVRCP: SDP query failed with status 0x%02x.", status);
578                 avrcp_emit_connection_established(sdp_query_context->avrcp_callback, connection->avrcp_cid, connection->remote_addr, status);
579                 avrcp_finalize_connection(connection);
580                 break;
581             }
582 
583             if (!sdp_query_context->avrcp_l2cap_psm){
584                 connection->state = AVCTP_CONNECTION_IDLE;
585                 log_info("AVRCP: no suitable service found");
586                 avrcp_emit_connection_established(sdp_query_context->avrcp_callback, connection->avrcp_cid, connection->remote_addr, SDP_SERVICE_NOT_FOUND);
587                 avrcp_finalize_connection(connection);
588                 break;
589             }
590             connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
591             l2cap_create_channel(&avrcp_packet_handler, connection->remote_addr, sdp_query_context->avrcp_l2cap_psm, l2cap_max_mtu(), NULL);
592             break;
593         }
594     }
595 }
596 
597 static btstack_packet_handler_t avrcp_packet_handler_for_role(avrcp_role_t role){
598     switch (role){
599         case AVRCP_CONTROLLER:
600             return avrcp_controller_packet_handler;
601         case AVRCP_TARGET:
602             return avrcp_target_packet_handler;
603     }
604     return NULL;
605 }
606 
607 static int avrcp_handle_incoming_connection_for_role(avrcp_role_t role, bd_addr_t event_addr, uint16_t local_cid){
608     if (!avrcp_packet_handler_for_role(role)) {
609         // printf("AVRCP: avrcp_handle_incoming_connection_for_role %d, PH not defined\n", role);
610         return 0;
611     }
612 
613     avrcp_connection_t * connection = avrcp_create_connection(role, event_addr);
614     if (!connection) {
615         // printf("AVRCP: avrcp_handle_incoming_connection_for_role %d, no connection created\n", role);
616         return 0 ;
617     }
618 
619     // printf("AVRCP: AVCTP_CONNECTION_W4_L2CAP_CONNECTED, role %d\n", role);
620     connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
621     connection->l2cap_signaling_cid = local_cid;
622     return 1;
623 }
624 
625 static void avrcp_handle_open_connection_for_role(avrcp_role_t role, bd_addr_t event_addr, uint16_t local_cid, uint16_t l2cap_mtu, uint8_t status){
626     // printf("AVRCP: avrcp_handle_open_connection_for_role %d\n", role);
627 
628     btstack_packet_handler_t packet_handler = avrcp_packet_handler_for_role(role);
629     if (!packet_handler) {
630         // printf("AVRCP: avrcp_handle_open_connection_for_role %d, PH not defined\n", role);
631         return;
632     }
633     avrcp_connection_t * connection = get_avrcp_connection_for_bd_addr(role, event_addr);
634     if (!connection) {
635         // printf("AVRCP: avrcp_handle_open_connection_for_role %d, no connection found\n", role);
636         return;
637     }
638 
639     if (connection->state == AVCTP_CONNECTION_OPENED) return;
640 
641     if (status != ERROR_CODE_SUCCESS){
642         log_info("L2CAP connection to connection %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
643         avrcp_emit_connection_established(packet_handler, connection->avrcp_cid, event_addr, status);
644         avrcp_finalize_connection(connection);
645         return;
646     }
647 
648     connection->l2cap_signaling_cid = local_cid;
649     connection->l2cap_mtu = l2cap_mtu;
650     connection->song_length_ms = 0xFFFFFFFF;
651     connection->song_position_ms = 0xFFFFFFFF;
652     connection->playback_status = AVRCP_PLAYBACK_STATUS_ERROR;
653 
654     log_info("L2CAP_EVENT_CHANNEL_OPENED avrcp_cid 0x%02x, l2cap_signaling_cid 0x%02x, role %d", connection->avrcp_cid, connection->l2cap_signaling_cid, connection->role);
655     connection->state = AVCTP_CONNECTION_OPENED;
656     // emit twice for each role
657     avrcp_emit_connection_established(packet_handler, connection->avrcp_cid, event_addr, ERROR_CODE_SUCCESS);
658 }
659 
660 static void avrcp_handle_close_connection_for_role(avrcp_role_t role,uint16_t local_cid){
661     // printf("AVRCP: avrcp_handle_close_connection_for_role %d\n", role);
662     btstack_packet_handler_t packet_handler = avrcp_packet_handler_for_role(role);
663     if (!packet_handler) return;
664 
665     avrcp_connection_t * connection = get_avrcp_connection_for_l2cap_signaling_cid(role, local_cid);
666     if (!connection) return;
667 
668     // printf("avrcp_handle_close_connection_for_role avrcp_cid 0x%02x, l2cap_signaling_cid 0x%02x, role %d\n", connection->avrcp_cid, connection->l2cap_signaling_cid, role);
669 
670     avrcp_emit_connection_closed(packet_handler, connection->avrcp_cid);
671     avrcp_finalize_connection(connection);
672 }
673 
674 static avrcp_role_t avrcp_role_from_transport_header(uint8_t transport_header){
675     avrcp_frame_type_t frame_type = (avrcp_frame_type_t)((transport_header & 0x02) >> 1);
676     switch (frame_type){
677         case AVRCP_COMMAND_FRAME:
678             return AVRCP_TARGET;
679         default: // AVRCP_RESPONSE_FRAME - make compiler happy
680             return AVRCP_CONTROLLER;
681     }
682 }
683 
684 static void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
685     UNUSED(channel);
686     UNUSED(size);
687     bd_addr_t event_addr;
688     uint16_t local_cid;
689     uint16_t l2cap_mtu;
690     uint8_t  status;
691     avrcp_connection_t * connection = NULL;
692     avrcp_role_t role;
693     btstack_packet_handler_t packet_handler;
694     uint8_t status_target;
695     uint8_t status_controller;
696 
697     switch (packet_type) {
698         case L2CAP_DATA_PACKET:
699             role = avrcp_role_from_transport_header(packet[0]);
700             packet_handler = avrcp_packet_handler_for_role(role);
701             if (!packet_handler) return;
702 
703             (*packet_handler)(packet_type, channel, packet, size);
704             break;
705 
706         case HCI_EVENT_PACKET:
707             switch (hci_event_packet_get_type(packet)) {
708 
709                 case L2CAP_EVENT_INCOMING_CONNECTION:
710                     l2cap_event_incoming_connection_get_address(packet, event_addr);
711                     local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
712                     // create two connection objects (both)
713                     status_target = avrcp_handle_incoming_connection_for_role(AVRCP_TARGET, event_addr, local_cid);
714                     status_controller = avrcp_handle_incoming_connection_for_role(AVRCP_CONTROLLER, event_addr, local_cid);
715 
716                     if (!status_target && !status_controller){
717                         l2cap_decline_connection(local_cid);
718                         break;
719                     }
720 
721                     log_info("AVRCP: L2CAP_EVENT_INCOMING_CONNECTION avrcp_cid 0x%02x", local_cid);
722                     l2cap_accept_connection(local_cid);
723                     break;
724 
725                 case L2CAP_EVENT_CHANNEL_OPENED:
726                     // printf("AVRCP: L2CAP_EVENT_CHANNEL_OPENED \n");
727                     l2cap_event_channel_opened_get_address(packet, event_addr);
728                     status = l2cap_event_channel_opened_get_status(packet);
729                     local_cid = l2cap_event_channel_opened_get_local_cid(packet);
730                     l2cap_mtu = l2cap_event_channel_opened_get_remote_mtu(packet);
731 
732                     avrcp_handle_open_connection_for_role(AVRCP_TARGET, event_addr, local_cid, l2cap_mtu, status);
733                     avrcp_handle_open_connection_for_role(AVRCP_CONTROLLER, event_addr, local_cid, l2cap_mtu, status);
734                     break;
735 
736                 case L2CAP_EVENT_CHANNEL_CLOSED:
737                     // data: event (8), len(8), channel (16)
738                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
739                     avrcp_handle_close_connection_for_role(AVRCP_TARGET, local_cid);
740                     avrcp_handle_close_connection_for_role(AVRCP_CONTROLLER, local_cid);
741                     break;
742 
743                 case L2CAP_EVENT_CAN_SEND_NOW:
744                     local_cid = l2cap_event_can_send_now_get_local_cid(packet);
745                     connection = get_avrcp_connection_for_l2cap_signaling_cid(AVRCP_TARGET, local_cid);
746                     if (connection && connection->wait_to_send){
747                         // printf("AVRCP: L2CAP_EVENT_CAN_SEND_NOW target\n");
748                         connection->wait_to_send = 0;
749                         (*avrcp_target_packet_handler)(HCI_EVENT_PACKET, channel, packet, size);
750                         break;
751                     }
752 
753                     connection = get_avrcp_connection_for_l2cap_signaling_cid(AVRCP_CONTROLLER, local_cid);
754                     if (connection && connection->wait_to_send){
755                         // printf("AVRCP: L2CAP_EVENT_CAN_SEND_NOW controller\n");
756                         connection->wait_to_send = 0;
757                         (*avrcp_controller_packet_handler)(HCI_EVENT_PACKET, channel, packet, size);
758                         break;
759                     }
760                     break;
761 
762                 default:
763                     break;
764             }
765             break;
766         default:
767             break;
768     }
769 }
770 
771 uint8_t avrcp_connect(avrcp_role_t role, bd_addr_t bd_addr, avrcp_context_t * context, uint16_t * avrcp_cid){
772     avrcp_connection_t * connection = get_avrcp_connection_for_bd_addr(context->role, bd_addr);
773     if (connection) return ERROR_CODE_COMMAND_DISALLOWED;
774 
775     if (!sdp_client_ready()) return ERROR_CODE_COMMAND_DISALLOWED;
776 
777     btstack_packet_handler_t packet_handler = avrcp_packet_handler_for_role(role);
778     if (!packet_handler) return 0;
779 
780     connection = avrcp_create_connection(role, bd_addr);
781     if (!connection) return BTSTACK_MEMORY_ALLOC_FAILED;
782 
783     if (avrcp_cid){
784         *avrcp_cid = connection->avrcp_cid;
785     }
786     context->avrcp_l2cap_psm = 0;
787     context->avrcp_version = 0;
788     context->avrcp_cid = connection->avrcp_cid;
789     connection->browsing_l2cap_psm = 0;
790     connection->state = AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE;
791     sdp_query_context = context;
792     sdp_client_query_uuid16(&avrcp_handle_sdp_client_query_result, connection->remote_addr, BLUETOOTH_PROTOCOL_AVCTP);
793     return ERROR_CODE_SUCCESS;
794 }
795 
796 void avrcp_init(void){
797     connections = NULL;
798     if (l2cap_service_registered) return;
799 
800     int status = l2cap_register_service(&avrcp_packet_handler, BLUETOOTH_PROTOCOL_AVCTP, 0xffff, LEVEL_2);
801     if (status != ERROR_CODE_SUCCESS) return;
802     l2cap_service_registered = 1;
803 }
804 
805 void avrcp_register_controller_packet_handler(btstack_packet_handler_t callback){
806     avrcp_controller_packet_handler = callback;
807 }
808 
809 void avrcp_register_target_packet_handler(btstack_packet_handler_t callback){
810     avrcp_target_packet_handler = callback;
811 }
812 
813