xref: /btstack/src/classic/avrcp_controller.c (revision 737e7617e75611e85b7500ffdc95496f74b78f48)
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_controller.c"
39 
40 #include <stdint.h>
41 #include <string.h>
42 #include <inttypes.h>
43 
44 #include "classic/avrcp.h"
45 #include "classic/avrcp_controller.h"
46 
47 #include "bluetooth_sdp.h"
48 #include "btstack_debug.h"
49 #include "btstack_event.h"
50 #include "btstack_util.h"
51 #include "l2cap.h"
52 
53 #define AVRCP_CMD_BUFFER_SIZE 30
54 
55 // made public in avrcp_controller.h
56 avrcp_context_t avrcp_controller_context;
57 
58 static uint8_t avrcp_controller_calc_next_transaction_label(uint8_t current_transaction_label){
59     current_transaction_label++;
60     if (current_transaction_label == 16){
61         current_transaction_label = 1;
62     }
63     return current_transaction_label;
64 }
65 
66 static uint8_t avrcp_controller_get_next_transaction_label(avrcp_connection_t * connection){
67     connection->transaction_id_counter = avrcp_controller_calc_next_transaction_label(connection->transaction_id_counter);
68     return connection->transaction_id_counter;
69 }
70 
71 static bool avrcp_controller_is_transaction_id_valid(avrcp_connection_t * connection, uint8_t transaction_id){
72     uint8_t delta = ((int8_t) transaction_id - connection->last_confirmed_transaction_id) & 0x0f;
73     return delta < 15;
74 }
75 
76 static uint16_t avrcp_get_max_payload_size_for_packet_type(avrcp_packet_type_t packet_type){
77     switch (packet_type){
78         case AVRCP_SINGLE_PACKET:
79             return AVRCP_CMD_BUFFER_SIZE - 3;
80         case AVRCP_START_PACKET:
81             return AVRCP_CMD_BUFFER_SIZE - 4;
82         case AVRCP_CONTINUE_PACKET:
83         case AVRCP_END_PACKET:
84             return AVRCP_CMD_BUFFER_SIZE - 1;
85         default:
86             btstack_assert(false);
87             return 0;
88     }
89 }
90 
91 static int avrcp_controller_supports_browsing(uint16_t controller_supported_features){
92     return controller_supported_features & AVRCP_FEATURE_MASK_BROWSING;
93 }
94 
95 static void avrcp_controller_emit_notification_complete(avrcp_connection_t * connection, uint8_t status, uint8_t event_id){
96     uint8_t event[7];
97     uint8_t pos = 0;
98     event[pos++] = HCI_EVENT_AVRCP_META;
99     event[pos++] = sizeof(event) - 2;
100     event[pos++] = AVRCP_SUBEVENT_ENABLE_NOTIFICATION_COMPLETE;
101     little_endian_store_16(event, pos, connection->avrcp_cid);
102     pos += 2;
103     event[pos++] = status;
104     event[pos++] = event_id;
105     UNUSED(pos);
106     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
107 }
108 
109 static void avrcp_controller_emit_supported_events(avrcp_connection_t * connection){
110     uint8_t ctype = (uint8_t) AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
111     uint8_t event_id;
112 
113     for (event_id = (uint8_t) AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
114         if ( (connection->remote_supported_notifications & (1<<event_id)) == 0){
115             continue;
116         }
117         uint8_t event[8];
118         uint8_t pos = 0;
119         event[pos++] = HCI_EVENT_AVRCP_META;
120         event[pos++] = sizeof(event) - 2;
121         event[pos++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID;
122         little_endian_store_16(event, pos, connection->avrcp_cid);
123         pos += 2;
124         event[pos++] = ctype;
125         event[pos++] = 0;
126         event[pos++] = event_id;
127         UNUSED(pos);
128         (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
129     }
130 
131     uint8_t event[7];
132     uint8_t pos = 0;
133     event[pos++] = HCI_EVENT_AVRCP_META;
134     event[pos++] = sizeof(event) - 2;
135     event[pos++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID_DONE;
136     little_endian_store_16(event, pos, connection->avrcp_cid);
137     pos += 2;
138     event[pos++] = ctype;
139     event[pos++] = 0;
140     UNUSED(pos);
141     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
142 }
143 
144 static void avrcp_controller_emit_notification_for_event_id(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id,
145                                                             avrcp_command_type_t ctype, const uint8_t *payload,
146                                                             uint16_t size) {
147     switch (event_id){
148         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_POS_CHANGED:{
149             if (size < 4) break;
150             uint32_t song_position = big_endian_read_32(payload, 0);
151             uint16_t offset = 0;
152             uint8_t event[10];
153             event[offset++] = HCI_EVENT_AVRCP_META;
154             event[offset++] = sizeof(event) - 2;
155             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_POS_CHANGED;
156             little_endian_store_16(event, offset, avrcp_cid);
157             offset += 2;
158             event[offset++] = ctype;
159             little_endian_store_32(event, offset, song_position);
160             offset += 4;
161             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
162             break;
163         }
164         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:{
165             if (size < 1) break;
166             uint16_t offset = 0;
167             uint8_t event[7];
168             event[offset++] = HCI_EVENT_AVRCP_META;
169             event[offset++] = sizeof(event) - 2;
170             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_STATUS_CHANGED;
171             little_endian_store_16(event, offset, avrcp_cid);
172             offset += 2;
173             event[offset++] = ctype;
174             event[offset++] = payload[0];
175             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
176             break;
177         }
178         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:{
179             uint16_t offset = 0;
180             uint8_t event[6];
181             event[offset++] = HCI_EVENT_AVRCP_META;
182             event[offset++] = sizeof(event) - 2;
183             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_TRACK_CHANGED;
184             little_endian_store_16(event, offset, avrcp_cid);
185             offset += 2;
186             event[offset++] = ctype;
187             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
188             break;
189         }
190         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:{
191             uint16_t offset = 0;
192             uint8_t event[6];
193             event[offset++] = HCI_EVENT_AVRCP_META;
194             event[offset++] = sizeof(event) - 2;
195             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_NOW_PLAYING_CONTENT_CHANGED;
196             little_endian_store_16(event, offset, avrcp_cid);
197             offset += 2;
198             event[offset++] = ctype;
199             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
200             break;
201         }
202         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:{
203             uint16_t offset = 0;
204             uint8_t event[6];
205             event[offset++] = HCI_EVENT_AVRCP_META;
206             event[offset++] = sizeof(event) - 2;
207             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_AVAILABLE_PLAYERS_CHANGED;
208             little_endian_store_16(event, offset, avrcp_cid);
209             offset += 2;
210             event[offset++] = ctype;
211             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
212             break;
213         }
214         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:{
215             if (size < 1) break;
216             uint16_t offset = 0;
217             uint8_t event[7];
218             event[offset++] = HCI_EVENT_AVRCP_META;
219             event[offset++] = sizeof(event) - 2;
220             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
221             little_endian_store_16(event, offset, avrcp_cid);
222             offset += 2;
223             event[offset++] = ctype;
224             event[offset++] = payload[0] & 0x7F;
225             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
226             break;
227         }
228         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:{
229             if (size < 2) break;
230             uint8_t event[8];
231             uint16_t offset = 0;
232             uint16_t uuid = big_endian_read_16(payload, 0);
233             event[offset++] = HCI_EVENT_AVRCP_META;
234             event[offset++] = sizeof(event) - 2;
235             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_UIDS_CHANGED;
236             little_endian_store_16(event, offset, avrcp_cid);
237             offset += 2;
238             event[offset++] = ctype;
239             little_endian_store_16(event, offset, uuid);
240             offset += 2;
241             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
242             break;
243         }
244 
245         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_END:{
246             uint16_t offset = 0;
247             uint8_t event[6];
248             event[offset++] = HCI_EVENT_AVRCP_META;
249             event[offset++] = sizeof(event) - 2;
250             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_END;
251             little_endian_store_16(event, offset, avrcp_cid);
252             offset += 2;
253             event[offset++] = ctype;
254             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
255             break;
256         }
257         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_START:{
258             uint16_t offset = 0;
259             uint8_t event[6];
260             event[offset++] = HCI_EVENT_AVRCP_META;
261             event[offset++] = sizeof(event) - 2;
262             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_START;
263             little_endian_store_16(event, offset, avrcp_cid);
264             offset += 2;
265             event[offset++] = ctype;
266             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
267             break;
268         }
269         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:{
270             if (size < 1) break;
271             uint16_t offset = 0;
272             uint8_t event[7];
273             event[offset++] = HCI_EVENT_AVRCP_META;
274             event[offset++] = sizeof(event) - 2;
275             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_BATT_STATUS_CHANGED;
276             little_endian_store_16(event, offset, avrcp_cid);
277             offset += 2;
278             event[offset++] = ctype;
279             event[offset++] = payload[0];
280             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
281             break;
282         }
283 
284         case AVRCP_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED:{
285             if (size < 1) break;
286             uint16_t offset = 0;
287             uint8_t event[7];
288             event[offset++] = HCI_EVENT_AVRCP_META;
289             event[offset++] = sizeof(event) - 2;
290             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED;
291             little_endian_store_16(event, offset, avrcp_cid);
292             offset += 2;
293             event[offset++] = ctype;
294             event[offset++] = payload[0];
295             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
296             break;
297         }
298 
299         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
300         default:
301             log_info("avrcp: not implemented");
302             break;
303     }
304 }
305 
306 static void avrcp_controller_emit_repeat_and_shuffle_mode(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t ctype, avrcp_repeat_mode_t repeat_mode, avrcp_shuffle_mode_t shuffle_mode){
307     btstack_assert(callback != NULL);
308 
309     uint8_t event[8];
310     int pos = 0;
311     event[pos++] = HCI_EVENT_AVRCP_META;
312     event[pos++] = sizeof(event) - 2;
313     event[pos++] = AVRCP_SUBEVENT_SHUFFLE_AND_REPEAT_MODE;
314     little_endian_store_16(event, pos, avrcp_cid);
315     pos += 2;
316     event[pos++] = ctype;
317     event[pos++] = repeat_mode;
318     event[pos++] = shuffle_mode;
319     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
320 }
321 
322 static void avrcp_controller_emit_now_playing_info_event_done(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t ctype, uint8_t status){
323     uint8_t event[7];
324     int pos = 0;
325     event[pos++] = HCI_EVENT_AVRCP_META;
326     event[pos++] = sizeof(event) - 2;
327     event[pos++] = AVRCP_SUBEVENT_NOW_PLAYING_INFO_DONE;
328     little_endian_store_16(event, pos, avrcp_cid);
329     pos += 2;
330     event[pos++] = ctype;
331     event[pos++] = status;
332     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
333 }
334 
335 static void avrcp_controller_emit_now_playing_info_event(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t ctype, avrcp_media_attribute_id_t attr_id, uint8_t * value, uint16_t value_len){
336     uint8_t event[HCI_EVENT_BUFFER_SIZE];
337     int pos = 0;
338     event[pos++] = HCI_EVENT_AVRCP_META;
339     // reserve one byte for subevent type and data len
340     int data_len_pos = pos;
341     pos++;
342     int subevent_type_pos = pos;
343     pos++;
344     little_endian_store_16(event, pos, avrcp_cid);
345     pos += 2;
346     event[pos++] = ctype;
347 
348     switch (attr_id){
349         case AVRCP_MEDIA_ATTR_TITLE:
350             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TITLE_INFO;
351             event[pos++] = value_len;
352             (void)memcpy(event + pos, value, value_len);
353             break;
354         case AVRCP_MEDIA_ATTR_ARTIST:
355             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ARTIST_INFO;
356             event[pos++] = value_len;
357             (void)memcpy(event + pos, value, value_len);
358             break;
359         case AVRCP_MEDIA_ATTR_ALBUM:
360             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ALBUM_INFO;
361             event[pos++] = value_len;
362             (void)memcpy(event + pos, value, value_len);
363             break;
364         case AVRCP_MEDIA_ATTR_GENRE:
365             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_GENRE_INFO;
366             event[pos++] = value_len;
367             (void)memcpy(event + pos, value, value_len);
368             break;
369         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
370             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_SONG_LENGTH_MS_INFO;
371             if (value){
372                 little_endian_store_32(event, pos, btstack_atoi((char *)value));
373             } else {
374                 little_endian_store_32(event, pos, 0);
375             }
376             pos += 4;
377             break;
378         case AVRCP_MEDIA_ATTR_TRACK:
379             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TRACK_INFO;
380             if (value){
381                 event[pos++] = btstack_atoi((char *)value);
382             } else {
383                 event[pos++] = 0;
384             }
385             break;
386         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
387             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TOTAL_TRACKS_INFO;
388             if (value){
389                 event[pos++] = btstack_atoi((char *)value);
390             } else {
391                 event[pos++] = 0;
392             }
393             break;
394         default:
395             break;
396     }
397     event[data_len_pos] = pos - 2;
398     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
399 }
400 
401 static void avrcp_controller_emit_operation_status(btstack_packet_handler_t callback, uint8_t subevent, uint16_t avrcp_cid, uint8_t ctype, uint8_t operation_id){
402     btstack_assert(callback != NULL);
403 
404     uint8_t event[7];
405     int pos = 0;
406     event[pos++] = HCI_EVENT_AVRCP_META;
407     event[pos++] = sizeof(event) - 2;
408     event[pos++] = subevent;
409     little_endian_store_16(event, pos, avrcp_cid);
410     pos += 2;
411     event[pos++] = ctype;
412     event[pos++] = operation_id;
413     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
414 }
415 
416 static void avrcp_parser_reset(avrcp_connection_t * connection){
417     connection->list_offset = 0;
418     connection->num_attributes = 0;
419     connection->num_parsed_attributes = 0;
420     connection->parser_attribute_header_pos = 0;
421     connection->num_received_fragments = 0;
422     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
423 }
424 
425 static void avrcp_parser_process_byte(uint8_t byte, avrcp_connection_t * connection, avrcp_command_type_t ctype){
426     uint16_t attribute_total_value_len;
427     uint32_t attribute_id;
428     switch(connection->parser_state){
429         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:
430             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
431             connection->list_offset++;
432 
433             if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN) return;
434 
435             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
436             connection->attribute_value_len = btstack_min(attribute_total_value_len, AVRCP_MAX_ATTRIBUTTE_SIZE);
437             if (connection->attribute_value_len > 0){
438                 // get ready for attribute value
439                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
440                 return;
441             }
442 
443             // emit empty attribute
444             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
445             avrcp_controller_emit_now_playing_info_event(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, (avrcp_media_attribute_id_t) attribute_id, connection->attribute_value, connection->attribute_value_len);
446 
447             // done, see below
448             break;
449 
450         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:
451             connection->attribute_value[connection->attribute_value_offset++] = byte;
452             connection->list_offset++;
453 
454             if (connection->attribute_value_offset < connection->attribute_value_len) return;
455 
456             // emit (potentially partial) attribute
457             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
458             avrcp_controller_emit_now_playing_info_event(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, (avrcp_media_attribute_id_t) attribute_id, connection->attribute_value, connection->attribute_value_len);
459 
460             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
461             if (connection->attribute_value_offset < attribute_total_value_len){
462                 // ignore rest of attribute
463                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
464                 return;
465             }
466 
467             // done, see below
468             break;
469 
470         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
471             connection->attribute_value_offset++;
472             connection->list_offset++;
473 
474             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
475             if (connection->attribute_value_offset < attribute_total_value_len) return;
476 
477             // done, see below
478             break;
479 
480         default:
481             return;
482     }
483 
484     // attribute fully read, check if more to come
485     if (connection->list_offset < connection->list_size){
486         // more to come, reset parser
487         connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
488         connection->parser_attribute_header_pos = 0;
489         connection->attribute_value_offset = 0;
490     } else {
491         // fully done
492         avrcp_parser_reset(connection);
493         avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 0);
494     }
495 }
496 
497 static void avrcp_controller_parse_and_emit_element_attrs(uint8_t * packet, uint16_t num_bytes_to_read, avrcp_connection_t * connection, avrcp_command_type_t ctype){
498     int i;
499     for (i=0;i<num_bytes_to_read;i++){
500         avrcp_parser_process_byte(packet[i], connection, ctype);
501     }
502 }
503 
504 
505 static int avrcp_send_cmd(avrcp_connection_t * connection, avrcp_packet_type_t packet_type){
506     uint8_t  command[AVRCP_CMD_BUFFER_SIZE];
507     uint16_t pos = 0;
508 
509     // non-fragmented: transport header (1) + PID (2)
510     // fragmented:     transport header (1) + num packets (1) + PID (2)
511 
512     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
513     command[pos++] = (connection->transaction_id << 4) | (packet_type << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
514 
515     if (packet_type == AVRCP_START_PACKET){
516         // num packets: (3 bytes overhead (PID, num packets) + command) / (MTU - transport header).
517         // to get number of packets using integer division, we subtract 1 from the data e.g. len = 5, packet size 5 => need 1 packet
518         command[pos++] = ((connection->cmd_operands_fragmented_len + 3 - 1) / (AVRCP_CMD_BUFFER_SIZE - 1)) + 1;
519     }
520 
521     if ((packet_type == AVRCP_SINGLE_PACKET) || (packet_type == AVRCP_START_PACKET)){
522         // Profile IDentifier (PID)
523         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
524         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
525 
526         // command_type
527         command[pos++] = connection->command_type;
528         // subunit_type | subunit ID
529         command[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
530         // opcode
531         command[pos++] = (uint8_t)connection->command_opcode;
532     }
533 
534     if (packet_type == AVRCP_SINGLE_PACKET){
535         // operands
536         (void)memcpy(command + pos, connection->cmd_operands,
537                      connection->cmd_operands_length);
538         pos += connection->cmd_operands_length;
539     } else {
540         uint16_t bytes_free = AVRCP_CMD_BUFFER_SIZE - pos;
541         uint16_t bytes_to_store = connection->cmd_operands_fragmented_len-connection->cmd_operands_fragmented_pos;
542         uint16_t bytes_to_copy = btstack_min(bytes_to_store, bytes_free);
543         (void)memcpy(command + pos,
544                      &connection->cmd_operands_fragmented_buffer[connection->cmd_operands_fragmented_pos],
545                      bytes_to_copy);
546         pos += bytes_to_copy;
547         connection->cmd_operands_fragmented_pos += bytes_to_copy;
548     }
549 
550     return l2cap_send(connection->l2cap_signaling_cid, command, pos);
551 }
552 
553 static int avrcp_send_register_notification(avrcp_connection_t * connection, uint8_t event_id){
554     uint8_t command[18];
555     uint16_t pos = 0;
556     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
557     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
558     command[pos++] = (connection->transaction_id << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
559 
560     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
561     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
562     command[pos++] = AVRCP_CTYPE_NOTIFY;
563     command[pos++] = (AVRCP_SUBUNIT_TYPE_PANEL << 3) | AVRCP_SUBUNIT_ID;
564     command[pos++] = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
565 
566     big_endian_store_24(command, pos, BT_SIG_COMPANY_ID);
567     pos += 3;
568     command[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
569     command[pos++] = 0;                       // reserved(upper 6) | packet_type -> 0
570     big_endian_store_16(command, pos, 5);     // parameter length
571     pos += 2;
572     command[pos++] = event_id;
573     big_endian_store_32(command, pos, 1);     // send notification on playback position every second, for other notifications it is ignored
574     pos += 4;
575     return l2cap_send(connection->l2cap_signaling_cid, command, pos);
576 }
577 
578 static void avrcp_press_and_hold_timeout_handler(btstack_timer_source_t * timer){
579     UNUSED(timer);
580     avrcp_connection_t * connection = (avrcp_connection_t*) btstack_run_loop_get_timer_context(timer);
581     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
582     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
583     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
584     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
585 }
586 
587 static void avrcp_press_and_hold_timer_start(avrcp_connection_t * connection){
588     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
589     btstack_run_loop_set_timer_handler(&connection->press_and_hold_cmd_timer, avrcp_press_and_hold_timeout_handler);
590     btstack_run_loop_set_timer_context(&connection->press_and_hold_cmd_timer, connection);
591     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
592     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
593 }
594 
595 static void avrcp_press_and_hold_timer_stop(avrcp_connection_t * connection){
596     connection->press_and_hold_cmd_active = false;
597     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
598 }
599 
600 
601 static uint8_t avrcp_controller_request_pass_through_release_control_cmd(avrcp_connection_t * connection){
602     connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
603     if (connection->press_and_hold_cmd_active){
604         avrcp_press_and_hold_timer_stop(connection);
605     }
606     connection->cmd_operands[0] = 0x80 | connection->cmd_operands[0];
607     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
608     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
609     return ERROR_CODE_SUCCESS;
610 }
611 
612 static uint8_t avrcp_controller_request_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed, bool continuous_cmd){
613     log_info("Send command %d", opid);
614     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
615     if (!connection){
616         log_error("Could not find a connection. avrcp cid 0x%02x", avrcp_cid);
617         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
618     }
619 
620     if (connection->state != AVCTP_CONNECTION_OPENED){
621         log_error("Connection in wrong state %d, expected %d. avrcp cid 0x%02x", connection->state, AVCTP_CONNECTION_OPENED, avrcp_cid);
622         return ERROR_CODE_COMMAND_DISALLOWED;
623     }
624     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
625     connection->command_opcode =  AVRCP_CMD_OPCODE_PASS_THROUGH;
626     connection->command_type = AVRCP_CTYPE_CONTROL;
627     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
628     connection->subunit_id =   AVRCP_SUBUNIT_ID;
629     connection->cmd_operands_length = 0;
630 
631     connection->press_and_hold_cmd_active = continuous_cmd;
632     connection->cmd_operands_length = 2;
633     connection->cmd_operands[0] = opid;
634     if (playback_speed > 0){
635         connection->cmd_operands[2] = playback_speed;
636         connection->cmd_operands_length++;
637     }
638     connection->cmd_operands[1] = connection->cmd_operands_length - 2;
639 
640     if (connection->press_and_hold_cmd_active){
641         avrcp_press_and_hold_timer_start(connection);
642     }
643 
644     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
645     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
646     return ERROR_CODE_SUCCESS;
647 }
648 
649 static uint8_t request_single_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
650     return avrcp_controller_request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, false);
651 }
652 
653 static uint8_t request_continuous_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
654     return avrcp_controller_request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, true);
655 }
656 
657 static void avrcp_controller_get_capabilities_for_connection(avrcp_connection_t * connection, uint8_t capability_id){
658     connection->state = AVCTP_W2_SEND_COMMAND;
659     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
660     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
661     connection->command_type = AVRCP_CTYPE_STATUS;
662     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
663     connection->subunit_id = AVRCP_SUBUNIT_ID;
664     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
665     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CAPABILITIES; // PDU ID
666     connection->cmd_operands[4] = 0;
667     big_endian_store_16(connection->cmd_operands, 5, 1); // parameter length
668     connection->cmd_operands[7] = capability_id;                  // capability ID
669     connection->cmd_operands_length = 8;
670     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
671 }
672 
673 static uint8_t avrcp_controller_register_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
674     if (connection->remote_supported_notifications_queried && (connection->remote_supported_notifications & (1 << event_id)) == 0){
675         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
676     }
677     if ( (connection->notifications_to_deregister & (1 << event_id)) != 0){
678         return ERROR_CODE_COMMAND_DISALLOWED;
679     }
680     if ( (connection->notifications_enabled & (1 << event_id)) != 0){
681         return ERROR_CODE_SUCCESS;
682     }
683     if ( (connection->notifications_to_register & (1 << event_id)) != 0){
684         return ERROR_CODE_SUCCESS;
685     }
686 
687     connection->notifications_to_register |= (1 << event_id);
688 
689     if (!connection->remote_supported_notifications_queried){
690         connection->remote_supported_notifications_suppress_emit_result = true;
691         avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
692         return ERROR_CODE_SUCCESS;
693     }
694     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
695     return ERROR_CODE_SUCCESS;
696 }
697 
698 static uint8_t avrcp_controller_request_abort_continuation(avrcp_connection_t * connection){
699     connection->state = AVCTP_W2_SEND_COMMAND;
700     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
701     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
702     connection->command_type = AVRCP_CTYPE_CONTROL;
703     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
704     connection->subunit_id = AVRCP_SUBUNIT_ID;
705     int pos = 0;
706     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
707     pos += 3;
708     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE; // PDU ID
709     connection->cmd_operands[pos++] = 0;
710     // Parameter Length
711     connection->cmd_operands_length = 8;
712     big_endian_store_16(connection->cmd_operands, pos, 1);
713     pos += 2;
714     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
715     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
716     return ERROR_CODE_SUCCESS;
717 }
718 
719 
720 static uint8_t avrcp_controller_request_continue_response(avrcp_connection_t * connection){
721     connection->state = AVCTP_W2_SEND_COMMAND;
722     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
723     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
724     connection->command_type = AVRCP_CTYPE_CONTROL;
725     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
726     connection->subunit_id = AVRCP_SUBUNIT_ID;
727     int pos = 0;
728     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
729     pos += 3;
730     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE; // PDU ID
731     connection->cmd_operands[pos++] = 0;
732     // Parameter Length
733     connection->cmd_operands_length = 8;
734     big_endian_store_16(connection->cmd_operands, pos, 1);
735     pos += 2;
736     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
737     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
738     return ERROR_CODE_SUCCESS;
739 }
740 
741 static void avrcp_controller_handle_notification(avrcp_connection_t *connection, avrcp_command_type_t ctype, uint8_t *payload, uint16_t size) {
742     if (size < 1) return;
743     uint16_t pos = 0;
744     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) payload[pos++];
745     uint16_t event_mask = (1 << event_id);
746     uint16_t reset_event_mask = ~event_mask;
747 
748     switch (ctype){
749         case AVRCP_CTYPE_RESPONSE_INTERIM:
750             // register as enabled
751             connection->notifications_enabled |= event_mask;
752             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_SUCCESS, event_id);
753             // check if initial value is already sent
754             if ( (connection->initial_status_reported & event_mask) > 0 ){
755                 return;
756             }
757             connection->initial_status_reported |= event_mask;
758             break;
759         case AVRCP_CTYPE_RESPONSE_CHANGED_STABLE:
760             // received change, event is considered de-registered
761             // we are re-enabling it automatically, if it is not
762             // explicitly disabled
763             connection->notifications_enabled &= reset_event_mask;
764             if (! (connection->notifications_to_deregister & event_mask)){
765                 avrcp_controller_register_notification(connection, event_id);
766             } else {
767                 connection->notifications_to_deregister &= reset_event_mask;
768             }
769             break;
770         default:
771             connection->notifications_to_register &= reset_event_mask;
772             connection->notifications_enabled &= reset_event_mask;
773             connection->notifications_to_deregister &= reset_event_mask;
774             break;
775     }
776 
777     avrcp_controller_emit_notification_for_event_id(connection->avrcp_cid, event_id, ctype, payload + pos, size - pos);
778 }
779 
780 #ifdef ENABLE_AVCTP_FRAGMENTATION
781 static void avctp_reassemble_message(avrcp_connection_t * connection, avctp_packet_type_t packet_type, uint8_t *packet, uint16_t size){
782     // after header (transaction label and packet type)
783     uint16_t pos;
784     uint16_t bytes_to_store;
785 
786     switch (packet_type){
787         case AVCTP_START_PACKET:
788             if (size < 2) return;
789 
790             // store header
791             pos = 0;
792             connection->avctp_reassembly_buffer[pos] = packet[pos];
793             pos++;
794             connection->avctp_reassembly_size = pos;
795 
796             // NOTE: num packets not needed for reassembly, ignoring it does not pose security risk -> no need to store it
797             pos++;
798 
799             // PID in reassembled packet is at offset 1, it will be read later after the avctp_reassemble_message with AVCTP_END_PACKET is called
800 
801             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
802             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
803             connection->avctp_reassembly_size += bytes_to_store;
804             break;
805 
806         case AVCTP_CONTINUE_PACKET:
807         case AVCTP_END_PACKET:
808             if (size < 1) return;
809 
810             // store remaining data, ignore header
811             pos = 1;
812             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
813             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
814             connection->avctp_reassembly_size += bytes_to_store;
815             break;
816 
817         default:
818             return;
819     }
820 }
821 #endif
822 
823 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
824     if (size < 6u) return;
825     uint8_t  pdu_id;
826     avrcp_packet_type_t  vendor_dependent_packet_type;
827 
828     uint16_t pos = 0;
829     connection->last_confirmed_transaction_id = packet[pos] >> 4;
830     avrcp_frame_type_t  frame_type =  (avrcp_frame_type_t)((packet[pos] >> 1) & 0x01);
831     avctp_packet_type_t packet_type = (avctp_packet_type_t)((packet[pos] >> 2) & 0x03);
832     pos++;
833 
834     if (frame_type != AVRCP_RESPONSE_FRAME) return;
835 
836     switch (packet_type){
837         case AVCTP_SINGLE_PACKET:
838             break;
839 
840 #ifdef ENABLE_AVCTP_FRAGMENTATION
841         case AVCTP_START_PACKET:
842         case AVCTP_CONTINUE_PACKET:
843             avctp_reassemble_message(connection, packet_type, packet, size);
844             return;
845 
846         case AVCTP_END_PACKET:
847             avctp_reassemble_message(connection, packet_type, packet, size);
848 
849             packet = connection->avctp_reassembly_buffer;
850             size   = connection->avctp_reassembly_size;
851             break;
852 #endif
853 
854         default:
855             return;
856     }
857 
858     pos += 2; // PID
859 
860     avrcp_command_type_t ctype = (avrcp_command_type_t) packet[pos++];
861 
862 #ifdef ENABLE_LOG_INFO
863     uint8_t byte_value = packet[pos];
864     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (byte_value >> 3);
865     avrcp_subunit_type_t subunit_id   = (avrcp_subunit_type_t) (byte_value & 0x07);
866 #endif
867     pos++;
868 
869     uint8_t opcode = packet[pos++];
870     uint16_t param_length;
871 
872     switch (opcode){
873         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
874             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
875             connection->state = AVCTP_CONNECTION_OPENED;
876 
877 #ifdef ENABLE_LOG_INFO
878             // page, extension code (1)
879             pos++;
880             uint8_t unit_type = packet[pos] >> 3;
881             uint8_t max_subunit_ID = packet[pos] & 0x07;
882             log_info("SUBUNIT INFO response: ctype 0x%02x (0C), subunit_type 0x%02x (1F), subunit_id 0x%02x (07), opcode 0x%02x (30), unit_type 0x%02x, max_subunit_ID %d", ctype, subunit_type, subunit_id, opcode, unit_type, max_subunit_ID);
883 #endif
884             break;
885         }
886         case AVRCP_CMD_OPCODE_UNIT_INFO:{
887             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
888             connection->state = AVCTP_CONNECTION_OPENED;
889 
890 #ifdef ENABLE_LOG_INFO
891             // byte value 7 (1)
892             pos++;
893             uint8_t unit_type = packet[pos] >> 3;
894             uint8_t unit = packet[pos] & 0x07;
895             pos++;
896             uint32_t company_id = big_endian_read_24(packet, pos);
897             log_info("UNIT INFO response: ctype 0x%02x (0C), subunit_type 0x%02x (1F), subunit_id 0x%02x (07), opcode 0x%02x (30), unit_type 0x%02x, unit %d, company_id 0x%06" PRIx32,
898                 ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id);
899 #endif
900             break;
901         }
902         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
903 
904             if ((size - pos) < 7) return;
905 
906             // Company ID (3)
907             pos += 3;
908             pdu_id = packet[pos++];
909             vendor_dependent_packet_type = (avrcp_packet_type_t)(packet[pos++] & 0x03);
910             param_length = big_endian_read_16(packet, pos);
911             pos += 2;
912 
913             if ((size - pos) < param_length) return;
914 
915             // handle asynchronous notifications, without changing state
916             if (pdu_id == AVRCP_PDU_ID_REGISTER_NOTIFICATION){
917                 avrcp_controller_handle_notification(connection, ctype, packet + pos, size - pos);
918                 break;
919             }
920 
921             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE){
922                 log_info("AVRCP_CMD_OPCODE_VENDOR_DEPENDENT state %d", connection->state);
923                 return;
924             }
925             connection->state = AVCTP_CONNECTION_OPENED;
926 
927             log_info("VENDOR DEPENDENT response: pdu id 0x%02x, param_length %d, status %s", pdu_id, param_length, avrcp_ctype2str(ctype));
928             switch (pdu_id){
929                 case AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE:{
930                     uint8_t num_attributes = packet[pos++];
931                     int i;
932                     avrcp_repeat_mode_t  repeat_mode =  AVRCP_REPEAT_MODE_INVALID;
933                     avrcp_shuffle_mode_t shuffle_mode = AVRCP_SHUFFLE_MODE_INVALID;
934                     for (i = 0; i < num_attributes; i++){
935                         uint8_t attribute_id    = packet[pos++];
936                         uint8_t value = packet[pos++];
937                         switch (attribute_id){
938                             case 0x02:
939                                 repeat_mode = (avrcp_repeat_mode_t) value;
940                                 break;
941                             case 0x03:
942                                 shuffle_mode = (avrcp_shuffle_mode_t) value;
943                                 break;
944                             default:
945                                 break;
946                         }
947                     }
948                     avrcp_controller_emit_repeat_and_shuffle_mode(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, repeat_mode, shuffle_mode);
949                     break;
950                 }
951 
952                 case AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE:{
953                     uint16_t offset = 0;
954                     uint8_t event[6];
955                     event[offset++] = HCI_EVENT_AVRCP_META;
956                     event[offset++] = sizeof(event) - 2;
957                     event[offset++] = AVRCP_SUBEVENT_PLAYER_APPLICATION_VALUE_RESPONSE;
958                     little_endian_store_16(event, offset, connection->avrcp_cid);
959                     offset += 2;
960                     event[offset++] = ctype;
961                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
962                     break;
963                 }
964 
965                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME:{
966                     uint16_t offset = 0;
967                     uint8_t event[7];
968                     event[offset++] = HCI_EVENT_AVRCP_META;
969                     event[offset++] = sizeof(event) - 2;
970                     event[offset++] = AVRCP_SUBEVENT_SET_ABSOLUTE_VOLUME_RESPONSE;
971                     little_endian_store_16(event, offset, connection->avrcp_cid);
972                     offset += 2;
973                     event[offset++] = ctype;
974                     event[offset++] = packet[pos++];
975                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
976                     break;
977                 }
978 
979                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
980                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos++];
981                     uint8_t capability_count = 0;
982                     if (param_length > 1){
983                         capability_count = packet[pos++];
984                     }
985                     uint16_t i;
986                     uint16_t offset = 0;
987                     uint8_t event[10];
988 
989                     switch (capability_id){
990 
991                         case AVRCP_CAPABILITY_ID_COMPANY:
992                             for (i = 0; (i < capability_count) && ((size - pos) >= 3); i++){
993                                 uint32_t company_id = big_endian_read_24(packet, pos);
994                                 pos += 3;
995                                 log_info("  0x%06" PRIx32 ", ", company_id);
996 
997                                 offset = 0;
998                                 event[offset++] = HCI_EVENT_AVRCP_META;
999                                 event[offset++] = sizeof(event) - 2;
1000                                 event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID;
1001                                 little_endian_store_16(event, offset, connection->avrcp_cid);
1002                                 offset += 2;
1003                                 event[offset++] = ctype;
1004                                 event[offset++] = 0;
1005                                 little_endian_store_24(event, offset, company_id);
1006                                 offset += 3;
1007                                 (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1008                             }
1009 
1010                             offset = 0;
1011                             event[offset++] = HCI_EVENT_AVRCP_META;
1012                             event[offset++] = sizeof(event) - 2;
1013                             event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID_DONE;
1014                             little_endian_store_16(event, offset, connection->avrcp_cid);
1015                             offset += 2;
1016                             event[offset++] = ctype;
1017                             event[offset++] = 0;
1018                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1019                             break;
1020 
1021                         case AVRCP_CAPABILITY_ID_EVENT:
1022                             for (i = 0; (i < capability_count) && ((size - pos) >= 1); i++){
1023                                 uint8_t event_id = packet[pos++];
1024                                 connection->remote_supported_notifications |= (1 << event_id);
1025                             }
1026                             if (connection->remote_supported_notifications_suppress_emit_result){
1027                                 connection->remote_supported_notifications_suppress_emit_result = false;
1028                                 break;
1029                             }
1030                             avrcp_controller_emit_supported_events(connection);
1031                             break;
1032 
1033                         default:
1034                             // ignore
1035                             break;
1036                     }
1037                     break;
1038                 }
1039 
1040                 case AVRCP_PDU_ID_GET_PLAY_STATUS:{
1041                     uint32_t song_length = big_endian_read_32(packet, pos);
1042                     pos += 4;
1043                     uint32_t song_position = big_endian_read_32(packet, pos);
1044                     pos += 4;
1045                     uint8_t play_status = packet[pos];
1046 
1047                     uint8_t event[15];
1048                     int offset = 0;
1049                     event[offset++] = HCI_EVENT_AVRCP_META;
1050                     event[offset++] = sizeof(event) - 2;
1051                     event[offset++] = AVRCP_SUBEVENT_PLAY_STATUS;
1052                     little_endian_store_16(event, offset, connection->avrcp_cid);
1053                     offset += 2;
1054                     event[offset++] = ctype;
1055                     little_endian_store_32(event, offset, song_length);
1056                     offset += 4;
1057                     little_endian_store_32(event, offset, song_position);
1058                     offset += 4;
1059                     event[offset++] = play_status;
1060                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1061                     break;
1062                 }
1063 
1064                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
1065                     switch (vendor_dependent_packet_type){
1066                         case AVRCP_START_PACKET:
1067                         case AVRCP_SINGLE_PACKET:
1068                             avrcp_parser_reset(connection);
1069                             connection->list_size = param_length;
1070                             connection->num_attributes = packet[pos++];
1071 
1072                             avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1073                             if (vendor_dependent_packet_type == AVRCP_START_PACKET){
1074                                 avrcp_controller_request_continue_response(connection);
1075                             }
1076                             break;
1077                         case AVRCP_CONTINUE_PACKET:
1078                         case AVRCP_END_PACKET:
1079                             connection->num_received_fragments++;
1080 
1081                             if (connection->num_received_fragments < connection->max_num_fragments){
1082                                 avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1083 
1084                                 if (vendor_dependent_packet_type == AVRCP_CONTINUE_PACKET){
1085                                     avrcp_controller_request_continue_response(connection);
1086                                 }
1087                             } else {
1088                                 avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 1);
1089                                 avrcp_parser_reset(connection);
1090                                 avrcp_controller_request_abort_continuation(connection);
1091                             }
1092                             break;
1093                         default:
1094                             // TODO check
1095                             btstack_assert(false);
1096                             break;
1097                     }
1098                 }
1099                 default:
1100                     break;
1101             }
1102             break;
1103         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
1104             if ((size - pos) < 1) return;
1105             uint8_t operation_id = packet[pos++];
1106             switch (connection->state){
1107                 case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1108                     // trigger release for simple command:
1109                     if (!connection->press_and_hold_cmd_active){
1110                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1111                         break;
1112                     }
1113                     // for press and hold, send release if it just has been requested, otherwise, wait for next repeat
1114                     if (connection->press_and_hold_cmd_release){
1115                         connection->press_and_hold_cmd_release = false;
1116                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1117                     } else {
1118                         connection->state = AVCTP_W4_STOP;
1119                     }
1120                     break;
1121                 case AVCTP_W2_RECEIVE_RESPONSE:
1122                     connection->state = AVCTP_CONNECTION_OPENED;
1123                     break;
1124                 default:
1125                     break;
1126             }
1127             if (connection->state == AVCTP_W4_STOP){
1128                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_START, connection->avrcp_cid, ctype, operation_id);
1129             }
1130             if (connection->state == AVCTP_CONNECTION_OPENED) {
1131                 // RELEASE response
1132                 operation_id = operation_id & 0x7F;
1133                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_COMPLETE, connection->avrcp_cid, ctype, operation_id);
1134             }
1135             if (connection->state == AVCTP_W2_SEND_RELEASE_COMMAND){
1136                 // PRESS response
1137                 avrcp_controller_request_pass_through_release_control_cmd(connection);
1138             }
1139             break;
1140         }
1141         default:
1142             break;
1143     }
1144 
1145     // trigger pending notification reqistrations
1146     if ((connection->state == AVCTP_CONNECTION_OPENED) && connection->notifications_to_register){
1147         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1148     }
1149 }
1150 
1151 static void avrcp_controller_handle_can_send_now(avrcp_connection_t * connection){
1152     switch (connection->state){
1153         case AVCTP_W2_SEND_PRESS_COMMAND:
1154             connection->state = AVCTP_W2_RECEIVE_PRESS_RESPONSE;
1155             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
1156             return;
1157         case AVCTP_W2_SEND_COMMAND:
1158         case AVCTP_W2_SEND_RELEASE_COMMAND:
1159             connection->state = AVCTP_W2_RECEIVE_RESPONSE;
1160             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
1161             return;
1162         case AVCTP_W2_SEND_FRAGMENTED_COMMAND:
1163             if (connection->cmd_operands_fragmented_pos == 0){
1164                  avrcp_send_cmd(connection, AVRCP_START_PACKET);
1165                  avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1166             } else {
1167                 if ((connection->cmd_operands_fragmented_len - connection->cmd_operands_fragmented_pos) > avrcp_get_max_payload_size_for_packet_type(AVRCP_CONTINUE_PACKET)){
1168                      avrcp_send_cmd(connection, AVRCP_CONTINUE_PACKET);
1169                      avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1170                  } else {
1171                     connection->state = AVCTP_W2_RECEIVE_RESPONSE;
1172                     avrcp_send_cmd(connection, AVRCP_END_PACKET);
1173                  }
1174             }
1175             return;
1176         default:
1177             break;
1178     }
1179     // send register notification if queued
1180     if (connection->notifications_to_register != 0){
1181         uint8_t event_id;
1182         for (event_id = (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t)AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
1183             if (connection->notifications_to_register & (1<<event_id)){
1184                 connection->notifications_to_register &= ~ (1 << event_id);
1185                 avrcp_send_register_notification(connection, event_id);
1186                 return;
1187             }
1188         }
1189     }
1190 }
1191 
1192 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1193     avrcp_connection_t * connection;
1194 
1195     switch (packet_type) {
1196         case L2CAP_DATA_PACKET:
1197             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1198             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1199             break;
1200 
1201         case HCI_EVENT_PACKET:
1202             switch (hci_event_packet_get_type(packet)){
1203                 case L2CAP_EVENT_CAN_SEND_NOW:
1204                     connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1205                     avrcp_controller_handle_can_send_now(connection);
1206                     break;
1207             default:
1208                 break;
1209         }
1210         default:
1211             break;
1212     }
1213 }
1214 
1215 void avrcp_controller_create_sdp_record(uint8_t * service, uint32_t service_record_handle, uint16_t supported_features, const char * service_name, const char * service_provider_name){
1216     avrcp_create_sdp_record(1, service, service_record_handle, avrcp_controller_supports_browsing(supported_features), supported_features, service_name, service_provider_name);
1217 }
1218 
1219 void avrcp_controller_init(void){
1220     avrcp_controller_context.role = AVRCP_CONTROLLER;
1221     avrcp_controller_context.packet_handler = avrcp_controller_packet_handler;
1222     avrcp_register_controller_packet_handler(&avrcp_controller_packet_handler);
1223 }
1224 
1225 void avrcp_controller_deinit(void){
1226     memset(&avrcp_controller_context, 0, sizeof(avrcp_context_t));
1227 }
1228 
1229 void avrcp_controller_register_packet_handler(btstack_packet_handler_t callback){
1230     btstack_assert(callback != NULL);
1231     avrcp_controller_context.avrcp_callback = callback;
1232 }
1233 
1234 
1235 uint8_t avrcp_controller_play(uint16_t avrcp_cid){
1236     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1237 }
1238 
1239 uint8_t avrcp_controller_stop(uint16_t avrcp_cid){
1240     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1241 }
1242 
1243 uint8_t avrcp_controller_pause(uint16_t avrcp_cid){
1244     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1245 }
1246 
1247 uint8_t avrcp_controller_forward(uint16_t avrcp_cid){
1248     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1249 }
1250 
1251 uint8_t avrcp_controller_backward(uint16_t avrcp_cid){
1252     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1253 }
1254 
1255 uint8_t avrcp_controller_volume_up(uint16_t avrcp_cid){
1256     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1257 }
1258 
1259 uint8_t avrcp_controller_volume_down(uint16_t avrcp_cid){
1260     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1261 }
1262 
1263 uint8_t avrcp_controller_mute(uint16_t avrcp_cid){
1264     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1265 }
1266 
1267 uint8_t avrcp_controller_skip(uint16_t avrcp_cid){
1268     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_SKIP, 0);
1269 }
1270 
1271 uint8_t avrcp_controller_fast_forward(uint16_t avrcp_cid){
1272     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1273 }
1274 
1275 uint8_t avrcp_controller_rewind(uint16_t avrcp_cid){
1276     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1277 }
1278 
1279 /* start continuous cmds */
1280 
1281 uint8_t avrcp_controller_start_press_and_hold_cmd(uint16_t avrcp_cid, avrcp_operation_id_t operation_id){
1282     return request_continuous_pass_through_press_control_cmd(avrcp_cid, operation_id, 0);
1283 }
1284 
1285 uint8_t avrcp_controller_press_and_hold_play(uint16_t avrcp_cid){
1286     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1287 }
1288 uint8_t avrcp_controller_press_and_hold_stop(uint16_t avrcp_cid){
1289     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1290 }
1291 uint8_t avrcp_controller_press_and_hold_pause(uint16_t avrcp_cid){
1292     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1293 }
1294 uint8_t avrcp_controller_press_and_hold_forward(uint16_t avrcp_cid){
1295     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1296 }
1297 uint8_t avrcp_controller_press_and_hold_backward(uint16_t avrcp_cid){
1298     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1299 }
1300 uint8_t avrcp_controller_press_and_hold_fast_forward(uint16_t avrcp_cid){
1301     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1302 }
1303 uint8_t avrcp_controller_press_and_hold_rewind(uint16_t avrcp_cid){
1304     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1305 }
1306 uint8_t avrcp_controller_press_and_hold_volume_up(uint16_t avrcp_cid){
1307     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1308 }
1309 uint8_t avrcp_controller_press_and_hold_volume_down(uint16_t avrcp_cid){
1310     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1311 }
1312 uint8_t avrcp_controller_press_and_hold_mute(uint16_t avrcp_cid){
1313     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1314 }
1315 
1316 /* stop continuous cmds */
1317 uint8_t avrcp_controller_release_press_and_hold_cmd(uint16_t avrcp_cid){
1318     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1319     if (!connection){
1320         log_error("avrcp_stop_play: could not find a connection.");
1321         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1322     }
1323 
1324     switch (connection->state){
1325         // respond when we receive response for (repeated) press command
1326         case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1327             connection->press_and_hold_cmd_release = true;
1328             break;
1329 
1330         // release already sent or on the way, nothing to do
1331         case AVCTP_W2_RECEIVE_RESPONSE:
1332         case AVCTP_W2_SEND_RELEASE_COMMAND:
1333             break;
1334 
1335         // about to send next repeated press command or wait for it -> release right away
1336         case AVCTP_W2_SEND_PRESS_COMMAND:
1337         case AVCTP_W4_STOP:
1338             return avrcp_controller_request_pass_through_release_control_cmd(connection);
1339 
1340         // otherwise reject request
1341         default:
1342             return ERROR_CODE_COMMAND_DISALLOWED;
1343     }
1344     return ERROR_CODE_SUCCESS;
1345 }
1346 
1347 uint8_t avrcp_controller_enable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1348     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1349     if (!connection){
1350         log_error("avrcp_get_play_status: could not find a connection.");
1351         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1352     }
1353     return avrcp_controller_register_notification(connection, event_id);
1354 }
1355 
1356 uint8_t avrcp_controller_disable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1357     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1358     if (!connection){
1359         log_error("avrcp_get_play_status: could not find a connection.");
1360         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1361     }
1362     connection->notifications_to_deregister |= (1 << event_id);
1363     return ERROR_CODE_SUCCESS;
1364 }
1365 
1366 uint8_t avrcp_controller_unit_info(uint16_t avrcp_cid){
1367     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1368     if (!connection){
1369         log_error("avrcp_unit_info: could not find a connection.");
1370         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1371     }
1372     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1373     connection->state = AVCTP_W2_SEND_COMMAND;
1374 
1375     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1376     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
1377     connection->command_type = AVRCP_CTYPE_STATUS;
1378     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
1379     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
1380     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
1381     connection->cmd_operands_length = 5;
1382     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1383     return ERROR_CODE_SUCCESS;
1384 }
1385 
1386 uint8_t avrcp_controller_subunit_info(uint16_t avrcp_cid){
1387     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1388     if (!connection){
1389         log_error("avrcp_unit_info: could not find a connection.");
1390         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1391     }
1392     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1393     connection->state = AVCTP_W2_SEND_COMMAND;
1394 
1395     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1396     connection->command_opcode = AVRCP_CMD_OPCODE_SUBUNIT_INFO;
1397     connection->command_type = AVRCP_CTYPE_STATUS;
1398     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
1399     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
1400     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
1401     connection->cmd_operands[0] = 7; // page: 0, extention_code: 7
1402     connection->cmd_operands_length = 5;
1403     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1404     return ERROR_CODE_SUCCESS;
1405 }
1406 
1407 uint8_t avrcp_controller_get_supported_company_ids(uint16_t avrcp_cid){
1408     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1409     if (!connection){
1410         log_error("avrcp_get_capabilities: could not find a connection.");
1411         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1412     }
1413     if (connection->state != AVCTP_CONNECTION_OPENED){
1414         return ERROR_CODE_COMMAND_DISALLOWED;
1415     }
1416     avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_COMPANY);
1417     return ERROR_CODE_SUCCESS;
1418 }
1419 
1420 uint8_t avrcp_controller_get_supported_events(uint16_t avrcp_cid){
1421     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1422     if (!connection){
1423         log_error("avrcp_get_capabilities: could not find a connection.");
1424         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1425     }
1426     if (connection->state != AVCTP_CONNECTION_OPENED){
1427         return ERROR_CODE_COMMAND_DISALLOWED;
1428     }
1429 
1430     if (!connection->remote_supported_notifications_queried){
1431         connection->remote_supported_notifications_queried = true;
1432         avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
1433         return ERROR_CODE_SUCCESS;
1434     }
1435 
1436     avrcp_controller_emit_supported_events(connection);
1437     return ERROR_CODE_SUCCESS;
1438 }
1439 
1440 uint8_t avrcp_controller_get_play_status(uint16_t avrcp_cid){
1441     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1442     if (!connection){
1443         log_error("avrcp_get_play_status: could not find a connection.");
1444         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1445     }
1446     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1447     connection->state = AVCTP_W2_SEND_COMMAND;
1448     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1449     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1450     connection->command_type = AVRCP_CTYPE_STATUS;
1451     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1452     connection->subunit_id = AVRCP_SUBUNIT_ID;
1453     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1454     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_PLAY_STATUS;
1455     connection->cmd_operands[4] = 0;                     // reserved(upper 6) | packet_type -> 0
1456     big_endian_store_16(connection->cmd_operands, 5, 0); // parameter length
1457     connection->cmd_operands_length = 7;
1458     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1459     return ERROR_CODE_SUCCESS;
1460 }
1461 
1462 uint8_t avrcp_controller_set_addressed_player(uint16_t avrcp_cid, uint16_t addressed_player_id){
1463     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1464     if (!connection){
1465         log_error("avrcp_get_capabilities: could not find a connection.");
1466         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1467     }
1468     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1469     connection->state = AVCTP_W2_SEND_COMMAND;
1470 
1471     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1472     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1473     connection->command_type = AVRCP_CTYPE_CONTROL;
1474     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1475     connection->subunit_id = AVRCP_SUBUNIT_ID;
1476     int pos = 0;
1477     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1478     pos += 3;
1479     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ADDRESSED_PLAYER; // PDU ID
1480     connection->cmd_operands[pos++] = 0;
1481 
1482     // Parameter Length
1483     big_endian_store_16(connection->cmd_operands, pos, 2);
1484     pos += 2;
1485 
1486     big_endian_store_16(connection->cmd_operands, pos, addressed_player_id);
1487     pos += 2;
1488 
1489     connection->cmd_operands_length = pos;
1490     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1491     return ERROR_CODE_SUCCESS;
1492 }
1493 
1494 uint8_t avrcp_controller_get_element_attributes(uint16_t avrcp_cid, uint8_t num_attributes, avrcp_media_attribute_id_t * attributes){
1495     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1496     if (!connection){
1497         log_error("avrcp_get_capabilities: could not find a connection.");
1498         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1499     }
1500 
1501     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1502 
1503     if (num_attributes >= AVRCP_MEDIA_ATTR_RESERVED) {
1504         return ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS;
1505     }
1506     connection->state = AVCTP_W2_SEND_COMMAND;
1507 
1508     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1509     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1510     connection->command_type = AVRCP_CTYPE_STATUS;
1511     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1512     connection->subunit_id = AVRCP_SUBUNIT_ID;
1513     int pos = 0;
1514     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1515     pos += 3;
1516     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES; // PDU ID
1517     connection->cmd_operands[pos++] = 0;
1518 
1519     // Parameter Length
1520     big_endian_store_16(connection->cmd_operands, pos, 9);
1521     pos += 2;
1522 
1523     // write 8 bytes value
1524     memset(connection->cmd_operands + pos, 0, 8); // identifier: PLAYING
1525     pos += 8;
1526 
1527     connection->cmd_operands[pos++] = num_attributes; // attribute count, if 0 get all attributes
1528 
1529     int i;
1530     for (i = 0; i < num_attributes; i++){
1531         // every attribute is 4 bytes long
1532         big_endian_store_32(connection->cmd_operands, pos, attributes[i]);
1533         pos += 4;
1534     }
1535 
1536     connection->cmd_operands_length = pos;
1537     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1538     return ERROR_CODE_SUCCESS;
1539 }
1540 
1541 uint8_t avrcp_controller_get_now_playing_info(uint16_t avrcp_cid){
1542     return avrcp_controller_get_element_attributes(avrcp_cid, 0, NULL);
1543 }
1544 
1545 uint8_t avrcp_controller_set_absolute_volume(uint16_t avrcp_cid, uint8_t volume){
1546      avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1547     if (!connection){
1548         log_error("avrcp_get_capabilities: could not find a connection.");
1549         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1550     }
1551 
1552     //
1553     // allow sending of multiple set abs volume commands without waiting for response
1554     //
1555     uint8_t status = ERROR_CODE_COMMAND_DISALLOWED;
1556     switch (connection->state){
1557         case AVCTP_CONNECTION_OPENED:
1558             status = ERROR_CODE_SUCCESS;
1559             break;
1560         case AVCTP_W2_RECEIVE_RESPONSE:
1561             // - is pending response also set abs volume
1562             if (connection->command_opcode  != AVRCP_CMD_OPCODE_VENDOR_DEPENDENT) break;
1563             if (connection->command_type    != AVRCP_CTYPE_CONTROL)               break;
1564             if (connection->subunit_type    != AVRCP_SUBUNIT_TYPE_PANEL)          break;
1565             if (connection->subunit_id      != AVRCP_SUBUNIT_ID)                  break;
1566             if (connection->cmd_operands[3] != AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME)  break;
1567             // - is next transaction id valid in window
1568             if (avrcp_controller_is_transaction_id_valid(connection, avrcp_controller_calc_next_transaction_label(connection->transaction_id_counter)) == false) break;
1569             status = ERROR_CODE_SUCCESS;
1570             break;
1571         default:
1572             break;
1573     }
1574     if (status != ERROR_CODE_SUCCESS) return status;
1575 
1576     connection->state = AVCTP_W2_SEND_COMMAND;
1577 
1578     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1579     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1580     connection->command_type = AVRCP_CTYPE_CONTROL;
1581     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1582     connection->subunit_id = AVRCP_SUBUNIT_ID;
1583     int pos = 0;
1584     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1585     pos += 3;
1586     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME; // PDU ID
1587     connection->cmd_operands[pos++] = 0;
1588 
1589     // Parameter Length
1590     big_endian_store_16(connection->cmd_operands, pos, 1);
1591     pos += 2;
1592     connection->cmd_operands[pos++] = volume;
1593 
1594     connection->cmd_operands_length = pos;
1595     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1596     return ERROR_CODE_SUCCESS;
1597 }
1598 
1599 uint8_t avrcp_controller_query_shuffle_and_repeat_modes(uint16_t avrcp_cid){
1600     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1601     if (!connection){
1602         log_error("avrcp_get_capabilities: could not find a connection.");
1603         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1604     }
1605     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1606     connection->state = AVCTP_W2_SEND_COMMAND;
1607 
1608     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1609     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1610     connection->command_type = AVRCP_CTYPE_STATUS;
1611     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1612     connection->subunit_id = AVRCP_SUBUNIT_ID;
1613     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1614     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE; // PDU ID
1615     connection->cmd_operands[4] = 0;
1616     big_endian_store_16(connection->cmd_operands, 5, 5); // parameter length
1617     connection->cmd_operands[7] = 4;                     // NumPlayerApplicationSettingAttributeID
1618     // PlayerApplicationSettingAttributeID1 AVRCP Spec, Appendix F, 133
1619     connection->cmd_operands[8]  = 0x01;    // equalizer  (1-OFF, 2-ON)
1620     connection->cmd_operands[9]  = 0x02;    // repeat     (1-off, 2-single track, 3-all tracks, 4-group repeat)
1621     connection->cmd_operands[10] = 0x03;    // shuffle    (1-off, 2-all tracks, 3-group shuffle)
1622     connection->cmd_operands[11] = 0x04;    // scan       (1-off, 2-all tracks, 3-group scan)
1623     connection->cmd_operands_length = 12;
1624     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1625     return ERROR_CODE_SUCCESS;
1626 }
1627 
1628 static uint8_t avrcp_controller_set_current_player_application_setting_value(uint16_t avrcp_cid, uint8_t attr_id, uint8_t attr_value){
1629     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1630     if (!connection){
1631         log_error("avrcp_get_capabilities: could not find a connection.");
1632         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1633     }
1634     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1635     connection->state = AVCTP_W2_SEND_COMMAND;
1636 
1637     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1638     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1639     connection->command_type = AVRCP_CTYPE_CONTROL;
1640     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1641     connection->subunit_id = AVRCP_SUBUNIT_ID;
1642     int pos = 0;
1643     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1644     pos += 3;
1645     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE; // PDU ID
1646     connection->cmd_operands[pos++] = 0;
1647     // Parameter Length
1648     big_endian_store_16(connection->cmd_operands, pos, 3);
1649     pos += 2;
1650     connection->cmd_operands[pos++] = 2;
1651     connection->cmd_operands_length = pos;
1652     connection->cmd_operands[pos++]  = attr_id;
1653     connection->cmd_operands[pos++]  = attr_value;
1654     connection->cmd_operands_length = pos;
1655     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1656     return ERROR_CODE_SUCCESS;
1657 }
1658 
1659 uint8_t avrcp_controller_set_shuffle_mode(uint16_t avrcp_cid, avrcp_shuffle_mode_t mode){
1660     if ((mode < AVRCP_SHUFFLE_MODE_OFF) || (mode > AVRCP_SHUFFLE_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1661     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x03, mode);
1662 }
1663 
1664 uint8_t avrcp_controller_set_repeat_mode(uint16_t avrcp_cid, avrcp_repeat_mode_t mode){
1665     if ((mode < AVRCP_REPEAT_MODE_OFF) || (mode > AVRCP_REPEAT_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1666     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x02, mode);
1667 }
1668 
1669 uint8_t avrcp_controller_play_item_for_scope(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1670     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1671     if (!connection){
1672         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1673         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1674     }
1675     if (connection->state != AVCTP_CONNECTION_OPENED){
1676         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1677         return ERROR_CODE_COMMAND_DISALLOWED;
1678     }
1679     connection->state = AVCTP_W2_SEND_COMMAND;
1680 
1681     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1682     connection->command_type = AVRCP_CTYPE_CONTROL;
1683     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1684     connection->subunit_id = AVRCP_SUBUNIT_ID;
1685     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1686     int pos = 0;
1687     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1688     pos += 3;
1689     connection->cmd_operands[pos++] = AVRCP_PDU_ID_PLAY_ITEM; // PDU ID
1690     // reserved
1691     connection->cmd_operands[pos++] = 0;
1692     // Parameter Length
1693     big_endian_store_16(connection->cmd_operands, pos, 11);
1694     pos += 2;
1695     connection->cmd_operands[pos++]  = scope;
1696     memset(&connection->cmd_operands[pos], 0, 8);
1697     if (uid){
1698         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1699     }
1700     pos += 8;
1701     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1702     pos += 2;
1703     connection->cmd_operands_length = pos;
1704 
1705     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1706     return ERROR_CODE_SUCCESS;
1707 }
1708 
1709 uint8_t avrcp_controller_add_item_from_scope_to_now_playing_list(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1710     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1711     if (!connection){
1712         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1713         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1714     }
1715     if (connection->state != AVCTP_CONNECTION_OPENED){
1716         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1717         return ERROR_CODE_COMMAND_DISALLOWED;
1718     }
1719     connection->state = AVCTP_W2_SEND_COMMAND;
1720 
1721     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1722     connection->command_type = AVRCP_CTYPE_CONTROL;
1723     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1724     connection->subunit_id = AVRCP_SUBUNIT_ID;
1725     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1726     int pos = 0;
1727     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1728     pos += 3;
1729     connection->cmd_operands[pos++] = AVRCP_PDU_ID_ADD_TO_NOW_PLAYING; // PDU ID
1730     // reserved
1731     connection->cmd_operands[pos++] = 0;
1732     // Parameter Length
1733     big_endian_store_16(connection->cmd_operands, pos, 11);
1734     pos += 2;
1735     connection->cmd_operands[pos++]  = scope;
1736     memset(&connection->cmd_operands[pos], 0, 8);
1737     if (uid){
1738         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1739     }
1740     pos += 8;
1741     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1742     pos += 2;
1743     connection->cmd_operands_length = pos;
1744 
1745     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1746     return ERROR_CODE_SUCCESS;
1747 }
1748 
1749 uint8_t avrcp_controller_set_max_num_fragments(uint16_t avrcp_cid, uint8_t max_num_fragments){
1750     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1751     if (!connection){
1752         log_error("avrcp_controller_play_item: could not find a connection.");
1753         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1754     }
1755     connection->max_num_fragments = max_num_fragments;
1756     return ERROR_CODE_SUCCESS;
1757 }
1758 
1759 uint8_t avrcp_controller_send_custom_command(uint16_t avrcp_cid, avrcp_command_type_t command_type, avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id, avrcp_command_opcode_t command_opcode, const uint8_t * command_buffer, uint16_t command_len){
1760     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1761     if (!connection){
1762         log_error("avrcp_controller_play_item: could not find a connection.");
1763         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1764     }
1765 
1766     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1767     connection->state = AVCTP_W2_SEND_FRAGMENTED_COMMAND;
1768 
1769     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1770     connection->command_opcode = command_opcode;
1771     connection->command_type = command_type;
1772     connection->subunit_type = subunit_type;
1773     connection->subunit_id = subunit_id;
1774     connection->cmd_operands_fragmented_buffer = command_buffer;
1775     connection->cmd_operands_fragmented_pos = 0;
1776     connection->cmd_operands_fragmented_len = command_len;
1777 
1778     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1779     return ERROR_CODE_SUCCESS;
1780 }
1781