xref: /btstack/src/classic/avrcp_controller.c (revision 1d3f7785eb3b8d7fad8b6dcf21a55a72d276b5ca)
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, bool enabled){
96     uint8_t event[8];
97     uint8_t pos = 0;
98     event[pos++] = HCI_EVENT_AVRCP_META;
99     event[pos++] = sizeof(event) - 2;
100     event[pos++] = AVRCP_SUBEVENT_NOTIFICATION_STATE;
101     little_endian_store_16(event, pos, connection->avrcp_cid);
102     pos += 2;
103     event[pos++] = status;
104     event[pos++] = enabled ? 1 : 0;
105     event[pos++] = event_id;
106     UNUSED(pos);
107     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
108 }
109 
110 static void avrcp_controller_emit_supported_events(avrcp_connection_t * connection){
111     uint8_t ctype = (uint8_t) AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
112     uint8_t event_id;
113 
114     for (event_id = (uint8_t) AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
115         if ( (connection->remote_supported_notifications & (1<<event_id)) == 0){
116             continue;
117         }
118         uint8_t event[8];
119         uint8_t pos = 0;
120         event[pos++] = HCI_EVENT_AVRCP_META;
121         event[pos++] = sizeof(event) - 2;
122         event[pos++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID;
123         little_endian_store_16(event, pos, connection->avrcp_cid);
124         pos += 2;
125         event[pos++] = ctype;
126         event[pos++] = 0;
127         event[pos++] = event_id;
128         UNUSED(pos);
129         (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
130     }
131 
132     uint8_t event[7];
133     uint8_t pos = 0;
134     event[pos++] = HCI_EVENT_AVRCP_META;
135     event[pos++] = sizeof(event) - 2;
136     event[pos++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID_DONE;
137     little_endian_store_16(event, pos, connection->avrcp_cid);
138     pos += 2;
139     event[pos++] = ctype;
140     event[pos++] = 0;
141     UNUSED(pos);
142     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
143 }
144 
145 static void avrcp_controller_emit_notification_for_event_id(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id,
146                                                             avrcp_command_type_t ctype, const uint8_t *payload,
147                                                             uint16_t size) {
148     switch (event_id){
149         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_POS_CHANGED:{
150             if (size < 4) break;
151             uint32_t song_position = big_endian_read_32(payload, 0);
152             uint16_t offset = 0;
153             uint8_t event[10];
154             event[offset++] = HCI_EVENT_AVRCP_META;
155             event[offset++] = sizeof(event) - 2;
156             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_POS_CHANGED;
157             little_endian_store_16(event, offset, avrcp_cid);
158             offset += 2;
159             event[offset++] = ctype;
160             little_endian_store_32(event, offset, song_position);
161             offset += 4;
162             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
163             break;
164         }
165         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:{
166             if (size < 1) break;
167             uint16_t offset = 0;
168             uint8_t event[7];
169             event[offset++] = HCI_EVENT_AVRCP_META;
170             event[offset++] = sizeof(event) - 2;
171             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_STATUS_CHANGED;
172             little_endian_store_16(event, offset, avrcp_cid);
173             offset += 2;
174             event[offset++] = ctype;
175             event[offset++] = payload[0];
176             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
177             break;
178         }
179         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:{
180             uint16_t offset = 0;
181             uint8_t event[6];
182             event[offset++] = HCI_EVENT_AVRCP_META;
183             event[offset++] = sizeof(event) - 2;
184             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_TRACK_CHANGED;
185             little_endian_store_16(event, offset, avrcp_cid);
186             offset += 2;
187             event[offset++] = ctype;
188             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
189             break;
190         }
191         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:{
192             uint16_t offset = 0;
193             uint8_t event[6];
194             event[offset++] = HCI_EVENT_AVRCP_META;
195             event[offset++] = sizeof(event) - 2;
196             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_NOW_PLAYING_CONTENT_CHANGED;
197             little_endian_store_16(event, offset, avrcp_cid);
198             offset += 2;
199             event[offset++] = ctype;
200             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
201             break;
202         }
203         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:{
204             uint16_t offset = 0;
205             uint8_t event[6];
206             event[offset++] = HCI_EVENT_AVRCP_META;
207             event[offset++] = sizeof(event) - 2;
208             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_AVAILABLE_PLAYERS_CHANGED;
209             little_endian_store_16(event, offset, avrcp_cid);
210             offset += 2;
211             event[offset++] = ctype;
212             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
213             break;
214         }
215         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:{
216             if (size < 1) break;
217             uint16_t offset = 0;
218             uint8_t event[7];
219             event[offset++] = HCI_EVENT_AVRCP_META;
220             event[offset++] = sizeof(event) - 2;
221             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
222             little_endian_store_16(event, offset, avrcp_cid);
223             offset += 2;
224             event[offset++] = ctype;
225             event[offset++] = payload[0] & 0x7F;
226             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
227             break;
228         }
229         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:{
230             if (size < 2) break;
231             uint8_t event[8];
232             uint16_t offset = 0;
233             uint16_t uuid = big_endian_read_16(payload, 0);
234             event[offset++] = HCI_EVENT_AVRCP_META;
235             event[offset++] = sizeof(event) - 2;
236             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_UIDS_CHANGED;
237             little_endian_store_16(event, offset, avrcp_cid);
238             offset += 2;
239             event[offset++] = ctype;
240             little_endian_store_16(event, offset, uuid);
241             offset += 2;
242             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
243             break;
244         }
245 
246         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_END:{
247             uint16_t offset = 0;
248             uint8_t event[6];
249             event[offset++] = HCI_EVENT_AVRCP_META;
250             event[offset++] = sizeof(event) - 2;
251             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_END;
252             little_endian_store_16(event, offset, avrcp_cid);
253             offset += 2;
254             event[offset++] = ctype;
255             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
256             break;
257         }
258         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_START:{
259             uint16_t offset = 0;
260             uint8_t event[6];
261             event[offset++] = HCI_EVENT_AVRCP_META;
262             event[offset++] = sizeof(event) - 2;
263             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_START;
264             little_endian_store_16(event, offset, avrcp_cid);
265             offset += 2;
266             event[offset++] = ctype;
267             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
268             break;
269         }
270         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:{
271             if (size < 1) break;
272             uint16_t offset = 0;
273             uint8_t event[7];
274             event[offset++] = HCI_EVENT_AVRCP_META;
275             event[offset++] = sizeof(event) - 2;
276             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_BATT_STATUS_CHANGED;
277             little_endian_store_16(event, offset, avrcp_cid);
278             offset += 2;
279             event[offset++] = ctype;
280             event[offset++] = payload[0];
281             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
282             break;
283         }
284 
285         case AVRCP_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED:{
286             if (size < 1) break;
287             uint16_t offset = 0;
288             uint8_t event[7];
289             event[offset++] = HCI_EVENT_AVRCP_META;
290             event[offset++] = sizeof(event) - 2;
291             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED;
292             little_endian_store_16(event, offset, avrcp_cid);
293             offset += 2;
294             event[offset++] = ctype;
295             event[offset++] = payload[0];
296             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
297             break;
298         }
299 
300         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
301         default:
302             log_info("avrcp: not implemented");
303             break;
304     }
305 }
306 
307 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){
308     btstack_assert(callback != NULL);
309 
310     uint8_t event[8];
311     int pos = 0;
312     event[pos++] = HCI_EVENT_AVRCP_META;
313     event[pos++] = sizeof(event) - 2;
314     event[pos++] = AVRCP_SUBEVENT_SHUFFLE_AND_REPEAT_MODE;
315     little_endian_store_16(event, pos, avrcp_cid);
316     pos += 2;
317     event[pos++] = ctype;
318     event[pos++] = repeat_mode;
319     event[pos++] = shuffle_mode;
320     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
321 }
322 
323 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){
324     uint8_t event[7];
325     int pos = 0;
326     event[pos++] = HCI_EVENT_AVRCP_META;
327     event[pos++] = sizeof(event) - 2;
328     event[pos++] = AVRCP_SUBEVENT_NOW_PLAYING_INFO_DONE;
329     little_endian_store_16(event, pos, avrcp_cid);
330     pos += 2;
331     event[pos++] = ctype;
332     event[pos++] = status;
333     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
334 }
335 
336 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){
337     uint8_t event[HCI_EVENT_BUFFER_SIZE];
338     int pos = 0;
339     event[pos++] = HCI_EVENT_AVRCP_META;
340     // reserve one byte for subevent type and data len
341     int data_len_pos = pos;
342     pos++;
343     int subevent_type_pos = pos;
344     pos++;
345     little_endian_store_16(event, pos, avrcp_cid);
346     pos += 2;
347     event[pos++] = ctype;
348 
349     switch (attr_id){
350         case AVRCP_MEDIA_ATTR_TITLE:
351             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TITLE_INFO;
352             event[pos++] = value_len;
353             (void)memcpy(event + pos, value, value_len);
354             break;
355         case AVRCP_MEDIA_ATTR_ARTIST:
356             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ARTIST_INFO;
357             event[pos++] = value_len;
358             (void)memcpy(event + pos, value, value_len);
359             break;
360         case AVRCP_MEDIA_ATTR_ALBUM:
361             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ALBUM_INFO;
362             event[pos++] = value_len;
363             (void)memcpy(event + pos, value, value_len);
364             break;
365         case AVRCP_MEDIA_ATTR_GENRE:
366             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_GENRE_INFO;
367             event[pos++] = value_len;
368             (void)memcpy(event + pos, value, value_len);
369             break;
370         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
371             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_SONG_LENGTH_MS_INFO;
372             if (value){
373                 little_endian_store_32(event, pos, btstack_atoi((char *)value));
374             } else {
375                 little_endian_store_32(event, pos, 0);
376             }
377             pos += 4;
378             break;
379         case AVRCP_MEDIA_ATTR_TRACK:
380             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TRACK_INFO;
381             if (value){
382                 event[pos++] = btstack_atoi((char *)value);
383             } else {
384                 event[pos++] = 0;
385             }
386             break;
387         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
388             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TOTAL_TRACKS_INFO;
389             if (value){
390                 event[pos++] = btstack_atoi((char *)value);
391             } else {
392                 event[pos++] = 0;
393             }
394             break;
395         default:
396             break;
397     }
398     event[data_len_pos] = pos - 2;
399     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
400 }
401 
402 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){
403     btstack_assert(callback != NULL);
404 
405     uint8_t event[7];
406     int pos = 0;
407     event[pos++] = HCI_EVENT_AVRCP_META;
408     event[pos++] = sizeof(event) - 2;
409     event[pos++] = subevent;
410     little_endian_store_16(event, pos, avrcp_cid);
411     pos += 2;
412     event[pos++] = ctype;
413     event[pos++] = operation_id;
414     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
415 }
416 
417 static void avrcp_parser_reset(avrcp_connection_t * connection){
418     connection->list_offset = 0;
419     connection->num_attributes = 0;
420     connection->num_parsed_attributes = 0;
421     connection->parser_attribute_header_pos = 0;
422     connection->num_received_fragments = 0;
423     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
424 }
425 
426 static void avrcp_parser_process_byte(uint8_t byte, avrcp_connection_t * connection, avrcp_command_type_t ctype){
427     uint16_t attribute_total_value_len;
428     uint32_t attribute_id;
429     switch(connection->parser_state){
430         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:
431             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
432             connection->list_offset++;
433 
434             if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN) return;
435 
436             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
437             connection->attribute_value_len = btstack_min(attribute_total_value_len, AVRCP_MAX_ATTRIBUTTE_SIZE);
438             if (connection->attribute_value_len > 0){
439                 // get ready for attribute value
440                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
441                 return;
442             }
443 
444             // emit empty attribute
445             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
446             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);
447 
448             // done, see below
449             break;
450 
451         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:
452             connection->attribute_value[connection->attribute_value_offset++] = byte;
453             connection->list_offset++;
454 
455             if (connection->attribute_value_offset < connection->attribute_value_len) return;
456 
457             // emit (potentially partial) attribute
458             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
459             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);
460 
461             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
462             if (connection->attribute_value_offset < attribute_total_value_len){
463                 // ignore rest of attribute
464                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
465                 return;
466             }
467 
468             // done, see below
469             break;
470 
471         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
472             connection->attribute_value_offset++;
473             connection->list_offset++;
474 
475             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
476             if (connection->attribute_value_offset < attribute_total_value_len) return;
477 
478             // done, see below
479             break;
480 
481         default:
482             return;
483     }
484 
485     // attribute fully read, check if more to come
486     if (connection->list_offset < connection->list_size){
487         // more to come, reset parser
488         connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
489         connection->parser_attribute_header_pos = 0;
490         connection->attribute_value_offset = 0;
491     } else {
492         // fully done
493         avrcp_parser_reset(connection);
494         avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 0);
495     }
496 }
497 
498 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){
499     int i;
500     for (i=0;i<num_bytes_to_read;i++){
501         avrcp_parser_process_byte(packet[i], connection, ctype);
502     }
503 }
504 
505 
506 static int avrcp_send_cmd(avrcp_connection_t * connection, avrcp_packet_type_t packet_type){
507     uint8_t  command[AVRCP_CMD_BUFFER_SIZE];
508     uint16_t pos = 0;
509 
510     // non-fragmented: transport header (1) + PID (2)
511     // fragmented:     transport header (1) + num packets (1) + PID (2)
512 
513     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
514     command[pos++] = (connection->transaction_id << 4) | (packet_type << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
515 
516     if (packet_type == AVRCP_START_PACKET){
517         // num packets: (3 bytes overhead (PID, num packets) + command) / (MTU - transport header).
518         // to get number of packets using integer division, we subtract 1 from the data e.g. len = 5, packet size 5 => need 1 packet
519         command[pos++] = ((connection->cmd_operands_fragmented_len + 3 - 1) / (AVRCP_CMD_BUFFER_SIZE - 1)) + 1;
520     }
521 
522     if ((packet_type == AVRCP_SINGLE_PACKET) || (packet_type == AVRCP_START_PACKET)){
523         // Profile IDentifier (PID)
524         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
525         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
526 
527         // command_type
528         command[pos++] = connection->command_type;
529         // subunit_type | subunit ID
530         command[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
531         // opcode
532         command[pos++] = (uint8_t)connection->command_opcode;
533     }
534 
535     if (packet_type == AVRCP_SINGLE_PACKET){
536         // operands
537         (void)memcpy(command + pos, connection->cmd_operands,
538                      connection->cmd_operands_length);
539         pos += connection->cmd_operands_length;
540     } else {
541         uint16_t bytes_free = AVRCP_CMD_BUFFER_SIZE - pos;
542         uint16_t bytes_to_store = connection->cmd_operands_fragmented_len-connection->cmd_operands_fragmented_pos;
543         uint16_t bytes_to_copy = btstack_min(bytes_to_store, bytes_free);
544         (void)memcpy(command + pos,
545                      &connection->cmd_operands_fragmented_buffer[connection->cmd_operands_fragmented_pos],
546                      bytes_to_copy);
547         pos += bytes_to_copy;
548         connection->cmd_operands_fragmented_pos += bytes_to_copy;
549     }
550 
551     return l2cap_send(connection->l2cap_signaling_cid, command, pos);
552 }
553 
554 static int avrcp_send_register_notification(avrcp_connection_t * connection, uint8_t event_id){
555     uint8_t command[18];
556     uint16_t pos = 0;
557     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
558     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
559     command[pos++] = (connection->transaction_id << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
560 
561     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
562     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
563     command[pos++] = AVRCP_CTYPE_NOTIFY;
564     command[pos++] = (AVRCP_SUBUNIT_TYPE_PANEL << 3) | AVRCP_SUBUNIT_ID;
565     command[pos++] = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
566 
567     big_endian_store_24(command, pos, BT_SIG_COMPANY_ID);
568     pos += 3;
569     command[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
570     command[pos++] = 0;                       // reserved(upper 6) | packet_type -> 0
571     big_endian_store_16(command, pos, 5);     // parameter length
572     pos += 2;
573     command[pos++] = event_id;
574     big_endian_store_32(command, pos, 1);     // send notification on playback position every second, for other notifications it is ignored
575     pos += 4;
576     return l2cap_send(connection->l2cap_signaling_cid, command, pos);
577 }
578 
579 static void avrcp_press_and_hold_timeout_handler(btstack_timer_source_t * timer){
580     UNUSED(timer);
581     avrcp_connection_t * connection = (avrcp_connection_t*) btstack_run_loop_get_timer_context(timer);
582     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
583     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
584     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
585     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
586 }
587 
588 static void avrcp_press_and_hold_timer_start(avrcp_connection_t * connection){
589     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
590     btstack_run_loop_set_timer_handler(&connection->press_and_hold_cmd_timer, avrcp_press_and_hold_timeout_handler);
591     btstack_run_loop_set_timer_context(&connection->press_and_hold_cmd_timer, connection);
592     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
593     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
594 }
595 
596 static void avrcp_press_and_hold_timer_stop(avrcp_connection_t * connection){
597     connection->press_and_hold_cmd_active = false;
598     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
599 }
600 
601 
602 static uint8_t avrcp_controller_request_pass_through_release_control_cmd(avrcp_connection_t * connection){
603     connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
604     if (connection->press_and_hold_cmd_active){
605         avrcp_press_and_hold_timer_stop(connection);
606     }
607     connection->cmd_operands[0] = 0x80 | connection->cmd_operands[0];
608     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
609     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
610     return ERROR_CODE_SUCCESS;
611 }
612 
613 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){
614     log_info("Send command %d", opid);
615     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
616     if (!connection){
617         log_error("Could not find a connection. avrcp cid 0x%02x", avrcp_cid);
618         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
619     }
620 
621     if (connection->state != AVCTP_CONNECTION_OPENED){
622         log_error("Connection in wrong state %d, expected %d. avrcp cid 0x%02x", connection->state, AVCTP_CONNECTION_OPENED, avrcp_cid);
623         return ERROR_CODE_COMMAND_DISALLOWED;
624     }
625     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
626     connection->command_opcode =  AVRCP_CMD_OPCODE_PASS_THROUGH;
627     connection->command_type = AVRCP_CTYPE_CONTROL;
628     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
629     connection->subunit_id =   AVRCP_SUBUNIT_ID;
630     connection->cmd_operands_length = 0;
631 
632     connection->press_and_hold_cmd_active = continuous_cmd;
633     connection->cmd_operands_length = 2;
634     connection->cmd_operands[0] = opid;
635     if (playback_speed > 0){
636         connection->cmd_operands[2] = playback_speed;
637         connection->cmd_operands_length++;
638     }
639     connection->cmd_operands[1] = connection->cmd_operands_length - 2;
640 
641     if (connection->press_and_hold_cmd_active){
642         avrcp_press_and_hold_timer_start(connection);
643     }
644 
645     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
646     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
647     return ERROR_CODE_SUCCESS;
648 }
649 
650 static uint8_t request_single_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
651     return avrcp_controller_request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, false);
652 }
653 
654 static uint8_t request_continuous_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
655     return avrcp_controller_request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, true);
656 }
657 
658 static void avrcp_controller_get_capabilities_for_connection(avrcp_connection_t * connection, uint8_t capability_id){
659     connection->state = AVCTP_W2_SEND_COMMAND;
660     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
661     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
662     connection->command_type = AVRCP_CTYPE_STATUS;
663     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
664     connection->subunit_id = AVRCP_SUBUNIT_ID;
665     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
666     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CAPABILITIES; // PDU ID
667     connection->cmd_operands[4] = 0;
668     big_endian_store_16(connection->cmd_operands, 5, 1); // parameter length
669     connection->cmd_operands[7] = capability_id;                  // capability ID
670     connection->cmd_operands_length = 8;
671     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
672 }
673 
674 static uint8_t avrcp_controller_register_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
675     if (connection->remote_supported_notifications_queried && (connection->remote_supported_notifications & (1 << event_id)) == 0){
676         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
677     }
678     if ( (connection->notifications_to_deregister & (1 << event_id)) != 0){
679         return ERROR_CODE_COMMAND_DISALLOWED;
680     }
681     if ( (connection->notifications_enabled & (1 << event_id)) != 0){
682         return ERROR_CODE_SUCCESS;
683     }
684     connection->notifications_to_register |= (1 << event_id);
685 
686     if (!connection->remote_supported_notifications_queried){
687         connection->remote_supported_notifications_suppress_emit_result = true;
688         avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
689         return ERROR_CODE_SUCCESS;
690     }
691     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
692     return ERROR_CODE_SUCCESS;
693 }
694 
695 static uint8_t avrcp_controller_request_abort_continuation(avrcp_connection_t * connection){
696     connection->state = AVCTP_W2_SEND_COMMAND;
697     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
698     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
699     connection->command_type = AVRCP_CTYPE_CONTROL;
700     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
701     connection->subunit_id = AVRCP_SUBUNIT_ID;
702     int pos = 0;
703     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
704     pos += 3;
705     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE; // PDU ID
706     connection->cmd_operands[pos++] = 0;
707     // Parameter Length
708     connection->cmd_operands_length = 8;
709     big_endian_store_16(connection->cmd_operands, pos, 1);
710     pos += 2;
711     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
712     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
713     return ERROR_CODE_SUCCESS;
714 }
715 
716 
717 static uint8_t avrcp_controller_request_continue_response(avrcp_connection_t * connection){
718     connection->state = AVCTP_W2_SEND_COMMAND;
719     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
720     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
721     connection->command_type = AVRCP_CTYPE_CONTROL;
722     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
723     connection->subunit_id = AVRCP_SUBUNIT_ID;
724     int pos = 0;
725     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
726     pos += 3;
727     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE; // PDU ID
728     connection->cmd_operands[pos++] = 0;
729     // Parameter Length
730     connection->cmd_operands_length = 8;
731     big_endian_store_16(connection->cmd_operands, pos, 1);
732     pos += 2;
733     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
734     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
735     return ERROR_CODE_SUCCESS;
736 }
737 
738 static void avrcp_controller_handle_notification(avrcp_connection_t *connection, avrcp_command_type_t ctype, uint8_t *payload, uint16_t size) {
739     if (size < 1) return;
740     uint16_t pos = 0;
741     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) payload[pos++];
742     if ( (event_id < AVRCP_NOTIFICATION_EVENT_FIRST_INDEX) || (event_id > AVRCP_NOTIFICATION_EVENT_LAST_INDEX)){
743         return;
744     }
745 
746     uint16_t event_mask = (1 << event_id);
747     uint16_t reset_event_mask = ~event_mask;
748 
749     switch (ctype){
750         case AVRCP_CTYPE_RESPONSE_INTERIM:
751             // register as enabled
752             connection->notifications_enabled |= event_mask;
753 
754             // check if initial value is already sent
755             if ( (connection->initial_status_reported & event_mask) != 0 ){
756                 return;
757             }
758             // emit event only once, initially
759             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_SUCCESS, event_id, true);
760             connection->initial_status_reported |= event_mask;
761             break;
762         case AVRCP_CTYPE_RESPONSE_CHANGED_STABLE:
763             // received change, event is considered de-registered
764             // we are re-enabling it automatically, if it is not
765             // explicitly disabled
766             connection->notifications_enabled &= reset_event_mask;
767             if ((connection->notifications_to_deregister & event_mask) == 0){
768                 avrcp_controller_register_notification(connection, event_id);
769             } else {
770                 connection->notifications_to_deregister &= reset_event_mask;
771                 connection->notifications_to_register   &= reset_event_mask;
772                 connection->initial_status_reported     &= reset_event_mask;
773                 avrcp_controller_emit_notification_complete(connection, ERROR_CODE_SUCCESS, event_id, false);
774             }
775             break;
776         default:
777             return;
778     }
779 
780     avrcp_controller_emit_notification_for_event_id(connection->avrcp_cid, event_id, ctype, payload + pos, size - pos);
781 }
782 
783 #ifdef ENABLE_AVCTP_FRAGMENTATION
784 static void avctp_reassemble_message(avrcp_connection_t * connection, avctp_packet_type_t packet_type, uint8_t *packet, uint16_t size){
785     // after header (transaction label and packet type)
786     uint16_t pos;
787     uint16_t bytes_to_store;
788 
789     switch (packet_type){
790         case AVCTP_START_PACKET:
791             if (size < 2) return;
792 
793             // store header
794             pos = 0;
795             connection->avctp_reassembly_buffer[pos] = packet[pos];
796             pos++;
797             connection->avctp_reassembly_size = pos;
798 
799             // NOTE: num packets not needed for reassembly, ignoring it does not pose security risk -> no need to store it
800             pos++;
801 
802             // PID in reassembled packet is at offset 1, it will be read later after the avctp_reassemble_message with AVCTP_END_PACKET is called
803 
804             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
805             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
806             connection->avctp_reassembly_size += bytes_to_store;
807             break;
808 
809         case AVCTP_CONTINUE_PACKET:
810         case AVCTP_END_PACKET:
811             if (size < 1) return;
812 
813             // store remaining data, ignore header
814             pos = 1;
815             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
816             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
817             connection->avctp_reassembly_size += bytes_to_store;
818             break;
819 
820         default:
821             return;
822     }
823 }
824 #endif
825 
826 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
827     if (size < 6u) return;
828     uint8_t  pdu_id;
829     avrcp_packet_type_t  vendor_dependent_packet_type;
830 
831     uint16_t pos = 0;
832     connection->last_confirmed_transaction_id = packet[pos] >> 4;
833     avrcp_frame_type_t  frame_type =  (avrcp_frame_type_t)((packet[pos] >> 1) & 0x01);
834     avctp_packet_type_t packet_type = (avctp_packet_type_t)((packet[pos] >> 2) & 0x03);
835     pos++;
836 
837     if (frame_type != AVRCP_RESPONSE_FRAME) return;
838 
839     switch (packet_type){
840         case AVCTP_SINGLE_PACKET:
841             break;
842 
843 #ifdef ENABLE_AVCTP_FRAGMENTATION
844         case AVCTP_START_PACKET:
845         case AVCTP_CONTINUE_PACKET:
846             avctp_reassemble_message(connection, packet_type, packet, size);
847             return;
848 
849         case AVCTP_END_PACKET:
850             avctp_reassemble_message(connection, packet_type, packet, size);
851 
852             packet = connection->avctp_reassembly_buffer;
853             size   = connection->avctp_reassembly_size;
854             break;
855 #endif
856 
857         default:
858             return;
859     }
860 
861     pos += 2; // PID
862 
863     avrcp_command_type_t ctype = (avrcp_command_type_t) packet[pos++];
864 
865 #ifdef ENABLE_LOG_INFO
866     uint8_t byte_value = packet[pos];
867     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (byte_value >> 3);
868     avrcp_subunit_type_t subunit_id   = (avrcp_subunit_type_t) (byte_value & 0x07);
869 #endif
870     pos++;
871 
872     uint8_t opcode = packet[pos++];
873     uint16_t param_length;
874 
875     switch (opcode){
876         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
877             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
878             connection->state = AVCTP_CONNECTION_OPENED;
879 
880 #ifdef ENABLE_LOG_INFO
881             // page, extension code (1)
882             pos++;
883             uint8_t unit_type = packet[pos] >> 3;
884             uint8_t max_subunit_ID = packet[pos] & 0x07;
885             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);
886 #endif
887             break;
888         }
889         case AVRCP_CMD_OPCODE_UNIT_INFO:{
890             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
891             connection->state = AVCTP_CONNECTION_OPENED;
892 
893 #ifdef ENABLE_LOG_INFO
894             // byte value 7 (1)
895             pos++;
896             uint8_t unit_type = packet[pos] >> 3;
897             uint8_t unit = packet[pos] & 0x07;
898             pos++;
899             uint32_t company_id = big_endian_read_24(packet, pos);
900             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,
901                 ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id);
902 #endif
903             break;
904         }
905         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
906 
907             if ((size - pos) < 7) return;
908 
909             // Company ID (3)
910             pos += 3;
911             pdu_id = packet[pos++];
912             vendor_dependent_packet_type = (avrcp_packet_type_t)(packet[pos++] & 0x03);
913             param_length = big_endian_read_16(packet, pos);
914             pos += 2;
915 
916             if ((size - pos) < param_length) return;
917 
918             // handle asynchronous notifications, without changing state
919             if (pdu_id == AVRCP_PDU_ID_REGISTER_NOTIFICATION){
920                 avrcp_controller_handle_notification(connection, ctype, packet + pos, size - pos);
921                 break;
922             }
923 
924             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE){
925                 log_info("AVRCP_CMD_OPCODE_VENDOR_DEPENDENT state %d", connection->state);
926                 return;
927             }
928             connection->state = AVCTP_CONNECTION_OPENED;
929 
930             log_info("VENDOR DEPENDENT response: pdu id 0x%02x, param_length %d, status %s", pdu_id, param_length, avrcp_ctype2str(ctype));
931             switch (pdu_id){
932                 case AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE:{
933                     uint8_t num_attributes = packet[pos++];
934                     int i;
935                     avrcp_repeat_mode_t  repeat_mode =  AVRCP_REPEAT_MODE_INVALID;
936                     avrcp_shuffle_mode_t shuffle_mode = AVRCP_SHUFFLE_MODE_INVALID;
937                     for (i = 0; i < num_attributes; i++){
938                         uint8_t attribute_id    = packet[pos++];
939                         uint8_t value = packet[pos++];
940                         switch (attribute_id){
941                             case 0x02:
942                                 repeat_mode = (avrcp_repeat_mode_t) value;
943                                 break;
944                             case 0x03:
945                                 shuffle_mode = (avrcp_shuffle_mode_t) value;
946                                 break;
947                             default:
948                                 break;
949                         }
950                     }
951                     avrcp_controller_emit_repeat_and_shuffle_mode(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, repeat_mode, shuffle_mode);
952                     break;
953                 }
954 
955                 case AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE:{
956                     uint16_t offset = 0;
957                     uint8_t event[6];
958                     event[offset++] = HCI_EVENT_AVRCP_META;
959                     event[offset++] = sizeof(event) - 2;
960                     event[offset++] = AVRCP_SUBEVENT_PLAYER_APPLICATION_VALUE_RESPONSE;
961                     little_endian_store_16(event, offset, connection->avrcp_cid);
962                     offset += 2;
963                     event[offset++] = ctype;
964                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
965                     break;
966                 }
967 
968                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME:{
969                     uint16_t offset = 0;
970                     uint8_t event[7];
971                     event[offset++] = HCI_EVENT_AVRCP_META;
972                     event[offset++] = sizeof(event) - 2;
973                     event[offset++] = AVRCP_SUBEVENT_SET_ABSOLUTE_VOLUME_RESPONSE;
974                     little_endian_store_16(event, offset, connection->avrcp_cid);
975                     offset += 2;
976                     event[offset++] = ctype;
977                     event[offset++] = packet[pos++];
978                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
979                     break;
980                 }
981 
982                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
983                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos++];
984                     uint8_t capability_count = 0;
985                     if (param_length > 1){
986                         capability_count = packet[pos++];
987                     }
988                     uint16_t i;
989                     uint16_t offset = 0;
990                     uint8_t event[10];
991 
992                     switch (capability_id){
993 
994                         case AVRCP_CAPABILITY_ID_COMPANY:
995                             for (i = 0; (i < capability_count) && ((size - pos) >= 3); i++){
996                                 uint32_t company_id = big_endian_read_24(packet, pos);
997                                 pos += 3;
998                                 log_info("  0x%06" PRIx32 ", ", company_id);
999 
1000                                 offset = 0;
1001                                 event[offset++] = HCI_EVENT_AVRCP_META;
1002                                 event[offset++] = sizeof(event) - 2;
1003                                 event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID;
1004                                 little_endian_store_16(event, offset, connection->avrcp_cid);
1005                                 offset += 2;
1006                                 event[offset++] = ctype;
1007                                 event[offset++] = 0;
1008                                 little_endian_store_24(event, offset, company_id);
1009                                 offset += 3;
1010                                 (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1011                             }
1012 
1013                             offset = 0;
1014                             event[offset++] = HCI_EVENT_AVRCP_META;
1015                             event[offset++] = sizeof(event) - 2;
1016                             event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID_DONE;
1017                             little_endian_store_16(event, offset, connection->avrcp_cid);
1018                             offset += 2;
1019                             event[offset++] = ctype;
1020                             event[offset++] = 0;
1021                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1022                             break;
1023 
1024                         case AVRCP_CAPABILITY_ID_EVENT:
1025                             for (i = 0; (i < capability_count) && ((size - pos) >= 1); i++){
1026                                 uint8_t event_id = packet[pos++];
1027                                 connection->remote_supported_notifications |= (1 << event_id);
1028                             }
1029 
1030                             // if the get supported events query is triggered by avrcp_controller_enable_notification call,
1031                             // avrcp_controller_emit_supported_events should be suppressed
1032                             if (connection->remote_supported_notifications_suppress_emit_result){
1033                                 connection->remote_supported_notifications_suppress_emit_result = false;
1034                                 // also, notification might not be supported
1035                                 // if so, emit AVRCP_SUBEVENT_ENABLE_NOTIFICATION_COMPLETE event to app,
1036                                 // and update notifications_to_register bitmap
1037                                 for (i = (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; i < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; i++){
1038                                     if ((connection->notifications_to_register & (1<<i)) != 0){
1039                                         if ((connection->remote_supported_notifications & (1<<i)) == 0){
1040                                             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE, i, false);
1041                                             connection->notifications_to_register &= ~(1 << i);
1042                                         }
1043                                     }
1044                                 }
1045                                 break;
1046                             }
1047                             // supported events are emitted only if the get supported events query
1048                             // is triggered by avrcp_controller_get_supported_events call
1049                             avrcp_controller_emit_supported_events(connection);
1050                             break;
1051 
1052                         default:
1053                             // ignore
1054                             break;
1055                     }
1056                     break;
1057                 }
1058 
1059                 case AVRCP_PDU_ID_GET_PLAY_STATUS:{
1060                     uint32_t song_length = big_endian_read_32(packet, pos);
1061                     pos += 4;
1062                     uint32_t song_position = big_endian_read_32(packet, pos);
1063                     pos += 4;
1064                     uint8_t play_status = packet[pos];
1065 
1066                     uint8_t event[15];
1067                     int offset = 0;
1068                     event[offset++] = HCI_EVENT_AVRCP_META;
1069                     event[offset++] = sizeof(event) - 2;
1070                     event[offset++] = AVRCP_SUBEVENT_PLAY_STATUS;
1071                     little_endian_store_16(event, offset, connection->avrcp_cid);
1072                     offset += 2;
1073                     event[offset++] = ctype;
1074                     little_endian_store_32(event, offset, song_length);
1075                     offset += 4;
1076                     little_endian_store_32(event, offset, song_position);
1077                     offset += 4;
1078                     event[offset++] = play_status;
1079                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1080                     break;
1081                 }
1082 
1083                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
1084                     switch (vendor_dependent_packet_type){
1085                         case AVRCP_START_PACKET:
1086                         case AVRCP_SINGLE_PACKET:
1087                             avrcp_parser_reset(connection);
1088                             connection->list_size = param_length;
1089                             connection->num_attributes = packet[pos++];
1090 
1091                             avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1092                             if (vendor_dependent_packet_type == AVRCP_START_PACKET){
1093                                 avrcp_controller_request_continue_response(connection);
1094                             }
1095                             break;
1096                         case AVRCP_CONTINUE_PACKET:
1097                         case AVRCP_END_PACKET:
1098                             connection->num_received_fragments++;
1099 
1100                             if (connection->num_received_fragments < connection->max_num_fragments){
1101                                 avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1102 
1103                                 if (vendor_dependent_packet_type == AVRCP_CONTINUE_PACKET){
1104                                     avrcp_controller_request_continue_response(connection);
1105                                 }
1106                             } else {
1107                                 avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 1);
1108                                 avrcp_parser_reset(connection);
1109                                 avrcp_controller_request_abort_continuation(connection);
1110                             }
1111                             break;
1112                         default:
1113                             // TODO check
1114                             btstack_assert(false);
1115                             break;
1116                     }
1117                 }
1118                 default:
1119                     break;
1120             }
1121             break;
1122         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
1123             if ((size - pos) < 1) return;
1124             uint8_t operation_id = packet[pos++];
1125             switch (connection->state){
1126                 case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1127                     // trigger release for simple command:
1128                     if (!connection->press_and_hold_cmd_active){
1129                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1130                         break;
1131                     }
1132                     // for press and hold, send release if it just has been requested, otherwise, wait for next repeat
1133                     if (connection->press_and_hold_cmd_release){
1134                         connection->press_and_hold_cmd_release = false;
1135                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1136                     } else {
1137                         connection->state = AVCTP_W4_STOP;
1138                     }
1139                     break;
1140                 case AVCTP_W2_RECEIVE_RESPONSE:
1141                     connection->state = AVCTP_CONNECTION_OPENED;
1142                     break;
1143                 default:
1144                     break;
1145             }
1146             if (connection->state == AVCTP_W4_STOP){
1147                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_START, connection->avrcp_cid, ctype, operation_id);
1148             }
1149             if (connection->state == AVCTP_CONNECTION_OPENED) {
1150                 // RELEASE response
1151                 operation_id = operation_id & 0x7F;
1152                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_COMPLETE, connection->avrcp_cid, ctype, operation_id);
1153             }
1154             if (connection->state == AVCTP_W2_SEND_RELEASE_COMMAND){
1155                 // PRESS response
1156                 avrcp_controller_request_pass_through_release_control_cmd(connection);
1157             }
1158             break;
1159         }
1160         default:
1161             break;
1162     }
1163 
1164     // trigger pending notification reqistrations
1165     if ((connection->state == AVCTP_CONNECTION_OPENED) && connection->notifications_to_register){
1166         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1167     }
1168 }
1169 
1170 static void avrcp_controller_handle_can_send_now(avrcp_connection_t * connection){
1171     switch (connection->state){
1172         case AVCTP_W2_SEND_PRESS_COMMAND:
1173             connection->state = AVCTP_W2_RECEIVE_PRESS_RESPONSE;
1174             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
1175             return;
1176         case AVCTP_W2_SEND_COMMAND:
1177         case AVCTP_W2_SEND_RELEASE_COMMAND:
1178             connection->state = AVCTP_W2_RECEIVE_RESPONSE;
1179             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
1180             return;
1181         case AVCTP_W2_SEND_FRAGMENTED_COMMAND:
1182             if (connection->cmd_operands_fragmented_pos == 0){
1183                  avrcp_send_cmd(connection, AVRCP_START_PACKET);
1184                  avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1185             } else {
1186                 if ((connection->cmd_operands_fragmented_len - connection->cmd_operands_fragmented_pos) > avrcp_get_max_payload_size_for_packet_type(AVRCP_CONTINUE_PACKET)){
1187                      avrcp_send_cmd(connection, AVRCP_CONTINUE_PACKET);
1188                      avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1189                  } else {
1190                     connection->state = AVCTP_W2_RECEIVE_RESPONSE;
1191                     avrcp_send_cmd(connection, AVRCP_END_PACKET);
1192                  }
1193             }
1194             return;
1195         default:
1196             break;
1197     }
1198     // send register notification if queued
1199     if (connection->notifications_to_register != 0){
1200         uint8_t event_id;
1201         for (event_id = (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t)AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
1202             if (connection->notifications_to_register & (1<<event_id)){
1203                 connection->notifications_to_register &= ~ (1 << event_id);
1204                 avrcp_send_register_notification(connection, event_id);
1205                 return;
1206             }
1207         }
1208     }
1209 }
1210 
1211 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1212     avrcp_connection_t * connection;
1213 
1214     switch (packet_type) {
1215         case L2CAP_DATA_PACKET:
1216             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1217             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1218             break;
1219 
1220         case HCI_EVENT_PACKET:
1221             switch (hci_event_packet_get_type(packet)){
1222                 case L2CAP_EVENT_CAN_SEND_NOW:
1223                     connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1224                     avrcp_controller_handle_can_send_now(connection);
1225                     break;
1226             default:
1227                 break;
1228         }
1229         default:
1230             break;
1231     }
1232 }
1233 
1234 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){
1235     avrcp_create_sdp_record(1, service, service_record_handle, avrcp_controller_supports_browsing(supported_features), supported_features, service_name, service_provider_name);
1236 }
1237 
1238 void avrcp_controller_init(void){
1239     avrcp_controller_context.role = AVRCP_CONTROLLER;
1240     avrcp_controller_context.packet_handler = avrcp_controller_packet_handler;
1241     avrcp_register_controller_packet_handler(&avrcp_controller_packet_handler);
1242 }
1243 
1244 void avrcp_controller_deinit(void){
1245     memset(&avrcp_controller_context, 0, sizeof(avrcp_context_t));
1246 }
1247 
1248 void avrcp_controller_register_packet_handler(btstack_packet_handler_t callback){
1249     btstack_assert(callback != NULL);
1250     avrcp_controller_context.avrcp_callback = callback;
1251 }
1252 
1253 
1254 uint8_t avrcp_controller_play(uint16_t avrcp_cid){
1255     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1256 }
1257 
1258 uint8_t avrcp_controller_stop(uint16_t avrcp_cid){
1259     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1260 }
1261 
1262 uint8_t avrcp_controller_pause(uint16_t avrcp_cid){
1263     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1264 }
1265 
1266 uint8_t avrcp_controller_forward(uint16_t avrcp_cid){
1267     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1268 }
1269 
1270 uint8_t avrcp_controller_backward(uint16_t avrcp_cid){
1271     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1272 }
1273 
1274 uint8_t avrcp_controller_volume_up(uint16_t avrcp_cid){
1275     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1276 }
1277 
1278 uint8_t avrcp_controller_volume_down(uint16_t avrcp_cid){
1279     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1280 }
1281 
1282 uint8_t avrcp_controller_mute(uint16_t avrcp_cid){
1283     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1284 }
1285 
1286 uint8_t avrcp_controller_skip(uint16_t avrcp_cid){
1287     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_SKIP, 0);
1288 }
1289 
1290 uint8_t avrcp_controller_fast_forward(uint16_t avrcp_cid){
1291     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1292 }
1293 
1294 uint8_t avrcp_controller_rewind(uint16_t avrcp_cid){
1295     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1296 }
1297 
1298 /* start continuous cmds */
1299 
1300 uint8_t avrcp_controller_start_press_and_hold_cmd(uint16_t avrcp_cid, avrcp_operation_id_t operation_id){
1301     return request_continuous_pass_through_press_control_cmd(avrcp_cid, operation_id, 0);
1302 }
1303 
1304 uint8_t avrcp_controller_press_and_hold_play(uint16_t avrcp_cid){
1305     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1306 }
1307 uint8_t avrcp_controller_press_and_hold_stop(uint16_t avrcp_cid){
1308     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1309 }
1310 uint8_t avrcp_controller_press_and_hold_pause(uint16_t avrcp_cid){
1311     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1312 }
1313 uint8_t avrcp_controller_press_and_hold_forward(uint16_t avrcp_cid){
1314     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1315 }
1316 uint8_t avrcp_controller_press_and_hold_backward(uint16_t avrcp_cid){
1317     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1318 }
1319 uint8_t avrcp_controller_press_and_hold_fast_forward(uint16_t avrcp_cid){
1320     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1321 }
1322 uint8_t avrcp_controller_press_and_hold_rewind(uint16_t avrcp_cid){
1323     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1324 }
1325 uint8_t avrcp_controller_press_and_hold_volume_up(uint16_t avrcp_cid){
1326     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1327 }
1328 uint8_t avrcp_controller_press_and_hold_volume_down(uint16_t avrcp_cid){
1329     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1330 }
1331 uint8_t avrcp_controller_press_and_hold_mute(uint16_t avrcp_cid){
1332     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1333 }
1334 
1335 /* stop continuous cmds */
1336 uint8_t avrcp_controller_release_press_and_hold_cmd(uint16_t avrcp_cid){
1337     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1338     if (!connection){
1339         log_error("avrcp_stop_play: could not find a connection.");
1340         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1341     }
1342 
1343     switch (connection->state){
1344         // respond when we receive response for (repeated) press command
1345         case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1346             connection->press_and_hold_cmd_release = true;
1347             break;
1348 
1349         // release already sent or on the way, nothing to do
1350         case AVCTP_W2_RECEIVE_RESPONSE:
1351         case AVCTP_W2_SEND_RELEASE_COMMAND:
1352             break;
1353 
1354         // about to send next repeated press command or wait for it -> release right away
1355         case AVCTP_W2_SEND_PRESS_COMMAND:
1356         case AVCTP_W4_STOP:
1357             return avrcp_controller_request_pass_through_release_control_cmd(connection);
1358 
1359         // otherwise reject request
1360         default:
1361             return ERROR_CODE_COMMAND_DISALLOWED;
1362     }
1363     return ERROR_CODE_SUCCESS;
1364 }
1365 
1366 uint8_t avrcp_controller_enable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1367     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1368     if (!connection){
1369         log_error("avrcp_get_play_status: could not find a connection.");
1370         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1371     }
1372     return avrcp_controller_register_notification(connection, event_id);
1373 }
1374 
1375 uint8_t avrcp_controller_disable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1376     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1377     if (!connection){
1378         log_error("avrcp_get_play_status: could not find a connection.");
1379         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1380     }
1381     if (!connection->remote_supported_notifications_queried){
1382         return ERROR_CODE_COMMAND_DISALLOWED;
1383     }
1384 
1385     if ((connection->remote_supported_notifications & (1 << event_id)) == 0){
1386         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1387     }
1388 
1389     if ((connection->notifications_enabled & (1 << event_id)) == 0){
1390         return ERROR_CODE_SUCCESS;
1391     }
1392 
1393     connection->notifications_to_deregister |= (1 << event_id);
1394     return ERROR_CODE_SUCCESS;
1395 }
1396 
1397 uint8_t avrcp_controller_unit_info(uint16_t avrcp_cid){
1398     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1399     if (!connection){
1400         log_error("avrcp_unit_info: could not find a connection.");
1401         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1402     }
1403     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1404     connection->state = AVCTP_W2_SEND_COMMAND;
1405 
1406     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1407     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
1408     connection->command_type = AVRCP_CTYPE_STATUS;
1409     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
1410     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
1411     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
1412     connection->cmd_operands_length = 5;
1413     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1414     return ERROR_CODE_SUCCESS;
1415 }
1416 
1417 uint8_t avrcp_controller_subunit_info(uint16_t avrcp_cid){
1418     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1419     if (!connection){
1420         log_error("avrcp_unit_info: could not find a connection.");
1421         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1422     }
1423     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1424     connection->state = AVCTP_W2_SEND_COMMAND;
1425 
1426     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1427     connection->command_opcode = AVRCP_CMD_OPCODE_SUBUNIT_INFO;
1428     connection->command_type = AVRCP_CTYPE_STATUS;
1429     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
1430     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
1431     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
1432     connection->cmd_operands[0] = 7; // page: 0, extention_code: 7
1433     connection->cmd_operands_length = 5;
1434     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1435     return ERROR_CODE_SUCCESS;
1436 }
1437 
1438 uint8_t avrcp_controller_get_supported_company_ids(uint16_t avrcp_cid){
1439     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1440     if (!connection){
1441         log_error("avrcp_get_capabilities: could not find a connection.");
1442         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1443     }
1444     if (connection->state != AVCTP_CONNECTION_OPENED){
1445         return ERROR_CODE_COMMAND_DISALLOWED;
1446     }
1447     avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_COMPANY);
1448     return ERROR_CODE_SUCCESS;
1449 }
1450 
1451 uint8_t avrcp_controller_get_supported_events(uint16_t avrcp_cid){
1452     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1453     if (!connection){
1454         log_error("avrcp_get_capabilities: could not find a connection.");
1455         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1456     }
1457     if (connection->state != AVCTP_CONNECTION_OPENED){
1458         return ERROR_CODE_COMMAND_DISALLOWED;
1459     }
1460 
1461     if (!connection->remote_supported_notifications_queried){
1462         connection->remote_supported_notifications_queried = true;
1463         avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
1464         return ERROR_CODE_SUCCESS;
1465     }
1466 
1467     avrcp_controller_emit_supported_events(connection);
1468     return ERROR_CODE_SUCCESS;
1469 }
1470 
1471 uint8_t avrcp_controller_get_play_status(uint16_t avrcp_cid){
1472     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1473     if (!connection){
1474         log_error("avrcp_get_play_status: could not find a connection.");
1475         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1476     }
1477     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1478     connection->state = AVCTP_W2_SEND_COMMAND;
1479     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1480     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1481     connection->command_type = AVRCP_CTYPE_STATUS;
1482     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1483     connection->subunit_id = AVRCP_SUBUNIT_ID;
1484     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1485     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_PLAY_STATUS;
1486     connection->cmd_operands[4] = 0;                     // reserved(upper 6) | packet_type -> 0
1487     big_endian_store_16(connection->cmd_operands, 5, 0); // parameter length
1488     connection->cmd_operands_length = 7;
1489     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1490     return ERROR_CODE_SUCCESS;
1491 }
1492 
1493 uint8_t avrcp_controller_set_addressed_player(uint16_t avrcp_cid, uint16_t addressed_player_id){
1494     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1495     if (!connection){
1496         log_error("avrcp_get_capabilities: could not find a connection.");
1497         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1498     }
1499     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1500     connection->state = AVCTP_W2_SEND_COMMAND;
1501 
1502     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1503     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1504     connection->command_type = AVRCP_CTYPE_CONTROL;
1505     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1506     connection->subunit_id = AVRCP_SUBUNIT_ID;
1507     int pos = 0;
1508     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1509     pos += 3;
1510     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ADDRESSED_PLAYER; // PDU ID
1511     connection->cmd_operands[pos++] = 0;
1512 
1513     // Parameter Length
1514     big_endian_store_16(connection->cmd_operands, pos, 2);
1515     pos += 2;
1516 
1517     big_endian_store_16(connection->cmd_operands, pos, addressed_player_id);
1518     pos += 2;
1519 
1520     connection->cmd_operands_length = pos;
1521     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1522     return ERROR_CODE_SUCCESS;
1523 }
1524 
1525 uint8_t avrcp_controller_get_element_attributes(uint16_t avrcp_cid, uint8_t num_attributes, avrcp_media_attribute_id_t * attributes){
1526     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1527     if (!connection){
1528         log_error("avrcp_get_capabilities: could not find a connection.");
1529         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1530     }
1531 
1532     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1533 
1534     if (num_attributes >= AVRCP_MEDIA_ATTR_RESERVED) {
1535         return ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS;
1536     }
1537     connection->state = AVCTP_W2_SEND_COMMAND;
1538 
1539     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1540     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1541     connection->command_type = AVRCP_CTYPE_STATUS;
1542     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1543     connection->subunit_id = AVRCP_SUBUNIT_ID;
1544     int pos = 0;
1545     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1546     pos += 3;
1547     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES; // PDU ID
1548     connection->cmd_operands[pos++] = 0;
1549 
1550     // Parameter Length
1551     big_endian_store_16(connection->cmd_operands, pos, 9);
1552     pos += 2;
1553 
1554     // write 8 bytes value
1555     memset(connection->cmd_operands + pos, 0, 8); // identifier: PLAYING
1556     pos += 8;
1557 
1558     connection->cmd_operands[pos++] = num_attributes; // attribute count, if 0 get all attributes
1559 
1560     int i;
1561     for (i = 0; i < num_attributes; i++){
1562         // every attribute is 4 bytes long
1563         big_endian_store_32(connection->cmd_operands, pos, attributes[i]);
1564         pos += 4;
1565     }
1566 
1567     connection->cmd_operands_length = pos;
1568     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1569     return ERROR_CODE_SUCCESS;
1570 }
1571 
1572 uint8_t avrcp_controller_get_now_playing_info(uint16_t avrcp_cid){
1573     return avrcp_controller_get_element_attributes(avrcp_cid, 0, NULL);
1574 }
1575 
1576 uint8_t avrcp_controller_set_absolute_volume(uint16_t avrcp_cid, uint8_t volume){
1577      avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1578     if (!connection){
1579         log_error("avrcp_get_capabilities: could not find a connection.");
1580         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1581     }
1582 
1583     //
1584     // allow sending of multiple set abs volume commands without waiting for response
1585     //
1586     uint8_t status = ERROR_CODE_COMMAND_DISALLOWED;
1587     switch (connection->state){
1588         case AVCTP_CONNECTION_OPENED:
1589             status = ERROR_CODE_SUCCESS;
1590             break;
1591         case AVCTP_W2_RECEIVE_RESPONSE:
1592             // - is pending response also set abs volume
1593             if (connection->command_opcode  != AVRCP_CMD_OPCODE_VENDOR_DEPENDENT) break;
1594             if (connection->command_type    != AVRCP_CTYPE_CONTROL)               break;
1595             if (connection->subunit_type    != AVRCP_SUBUNIT_TYPE_PANEL)          break;
1596             if (connection->subunit_id      != AVRCP_SUBUNIT_ID)                  break;
1597             if (connection->cmd_operands[3] != AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME)  break;
1598             // - is next transaction id valid in window
1599             if (avrcp_controller_is_transaction_id_valid(connection, avrcp_controller_calc_next_transaction_label(connection->transaction_id_counter)) == false) break;
1600             status = ERROR_CODE_SUCCESS;
1601             break;
1602         default:
1603             break;
1604     }
1605     if (status != ERROR_CODE_SUCCESS) return status;
1606 
1607     connection->state = AVCTP_W2_SEND_COMMAND;
1608 
1609     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1610     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1611     connection->command_type = AVRCP_CTYPE_CONTROL;
1612     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1613     connection->subunit_id = AVRCP_SUBUNIT_ID;
1614     int pos = 0;
1615     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1616     pos += 3;
1617     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME; // PDU ID
1618     connection->cmd_operands[pos++] = 0;
1619 
1620     // Parameter Length
1621     big_endian_store_16(connection->cmd_operands, pos, 1);
1622     pos += 2;
1623     connection->cmd_operands[pos++] = volume;
1624 
1625     connection->cmd_operands_length = pos;
1626     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1627     return ERROR_CODE_SUCCESS;
1628 }
1629 
1630 uint8_t avrcp_controller_query_shuffle_and_repeat_modes(uint16_t avrcp_cid){
1631     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1632     if (!connection){
1633         log_error("avrcp_get_capabilities: could not find a connection.");
1634         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1635     }
1636     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1637     connection->state = AVCTP_W2_SEND_COMMAND;
1638 
1639     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1640     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1641     connection->command_type = AVRCP_CTYPE_STATUS;
1642     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1643     connection->subunit_id = AVRCP_SUBUNIT_ID;
1644     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1645     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE; // PDU ID
1646     connection->cmd_operands[4] = 0;
1647     big_endian_store_16(connection->cmd_operands, 5, 5); // parameter length
1648     connection->cmd_operands[7] = 4;                     // NumPlayerApplicationSettingAttributeID
1649     // PlayerApplicationSettingAttributeID1 AVRCP Spec, Appendix F, 133
1650     connection->cmd_operands[8]  = 0x01;    // equalizer  (1-OFF, 2-ON)
1651     connection->cmd_operands[9]  = 0x02;    // repeat     (1-off, 2-single track, 3-all tracks, 4-group repeat)
1652     connection->cmd_operands[10] = 0x03;    // shuffle    (1-off, 2-all tracks, 3-group shuffle)
1653     connection->cmd_operands[11] = 0x04;    // scan       (1-off, 2-all tracks, 3-group scan)
1654     connection->cmd_operands_length = 12;
1655     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1656     return ERROR_CODE_SUCCESS;
1657 }
1658 
1659 static uint8_t avrcp_controller_set_current_player_application_setting_value(uint16_t avrcp_cid, uint8_t attr_id, uint8_t attr_value){
1660     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1661     if (!connection){
1662         log_error("avrcp_get_capabilities: could not find a connection.");
1663         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1664     }
1665     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1666     connection->state = AVCTP_W2_SEND_COMMAND;
1667 
1668     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1669     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1670     connection->command_type = AVRCP_CTYPE_CONTROL;
1671     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1672     connection->subunit_id = AVRCP_SUBUNIT_ID;
1673     int pos = 0;
1674     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1675     pos += 3;
1676     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE; // PDU ID
1677     connection->cmd_operands[pos++] = 0;
1678     // Parameter Length
1679     big_endian_store_16(connection->cmd_operands, pos, 3);
1680     pos += 2;
1681     connection->cmd_operands[pos++] = 2;
1682     connection->cmd_operands_length = pos;
1683     connection->cmd_operands[pos++]  = attr_id;
1684     connection->cmd_operands[pos++]  = attr_value;
1685     connection->cmd_operands_length = pos;
1686     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1687     return ERROR_CODE_SUCCESS;
1688 }
1689 
1690 uint8_t avrcp_controller_set_shuffle_mode(uint16_t avrcp_cid, avrcp_shuffle_mode_t mode){
1691     if ((mode < AVRCP_SHUFFLE_MODE_OFF) || (mode > AVRCP_SHUFFLE_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1692     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x03, mode);
1693 }
1694 
1695 uint8_t avrcp_controller_set_repeat_mode(uint16_t avrcp_cid, avrcp_repeat_mode_t mode){
1696     if ((mode < AVRCP_REPEAT_MODE_OFF) || (mode > AVRCP_REPEAT_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1697     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x02, mode);
1698 }
1699 
1700 uint8_t avrcp_controller_play_item_for_scope(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1701     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1702     if (!connection){
1703         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1704         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1705     }
1706     if (connection->state != AVCTP_CONNECTION_OPENED){
1707         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1708         return ERROR_CODE_COMMAND_DISALLOWED;
1709     }
1710     connection->state = AVCTP_W2_SEND_COMMAND;
1711 
1712     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1713     connection->command_type = AVRCP_CTYPE_CONTROL;
1714     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1715     connection->subunit_id = AVRCP_SUBUNIT_ID;
1716     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1717     int pos = 0;
1718     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1719     pos += 3;
1720     connection->cmd_operands[pos++] = AVRCP_PDU_ID_PLAY_ITEM; // PDU ID
1721     // reserved
1722     connection->cmd_operands[pos++] = 0;
1723     // Parameter Length
1724     big_endian_store_16(connection->cmd_operands, pos, 11);
1725     pos += 2;
1726     connection->cmd_operands[pos++]  = scope;
1727     memset(&connection->cmd_operands[pos], 0, 8);
1728     if (uid){
1729         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1730     }
1731     pos += 8;
1732     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1733     pos += 2;
1734     connection->cmd_operands_length = pos;
1735 
1736     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1737     return ERROR_CODE_SUCCESS;
1738 }
1739 
1740 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){
1741     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1742     if (!connection){
1743         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1744         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1745     }
1746     if (connection->state != AVCTP_CONNECTION_OPENED){
1747         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1748         return ERROR_CODE_COMMAND_DISALLOWED;
1749     }
1750     connection->state = AVCTP_W2_SEND_COMMAND;
1751 
1752     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1753     connection->command_type = AVRCP_CTYPE_CONTROL;
1754     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1755     connection->subunit_id = AVRCP_SUBUNIT_ID;
1756     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1757     int pos = 0;
1758     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1759     pos += 3;
1760     connection->cmd_operands[pos++] = AVRCP_PDU_ID_ADD_TO_NOW_PLAYING; // PDU ID
1761     // reserved
1762     connection->cmd_operands[pos++] = 0;
1763     // Parameter Length
1764     big_endian_store_16(connection->cmd_operands, pos, 11);
1765     pos += 2;
1766     connection->cmd_operands[pos++]  = scope;
1767     memset(&connection->cmd_operands[pos], 0, 8);
1768     if (uid){
1769         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1770     }
1771     pos += 8;
1772     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1773     pos += 2;
1774     connection->cmd_operands_length = pos;
1775 
1776     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1777     return ERROR_CODE_SUCCESS;
1778 }
1779 
1780 uint8_t avrcp_controller_set_max_num_fragments(uint16_t avrcp_cid, uint8_t max_num_fragments){
1781     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1782     if (!connection){
1783         log_error("avrcp_controller_play_item: could not find a connection.");
1784         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1785     }
1786     connection->max_num_fragments = max_num_fragments;
1787     return ERROR_CODE_SUCCESS;
1788 }
1789 
1790 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){
1791     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1792     if (!connection){
1793         log_error("avrcp_controller_play_item: could not find a connection.");
1794         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1795     }
1796 
1797     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1798     connection->state = AVCTP_W2_SEND_FRAGMENTED_COMMAND;
1799 
1800     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1801     connection->command_opcode = command_opcode;
1802     connection->command_type = command_type;
1803     connection->subunit_type = subunit_type;
1804     connection->subunit_id = subunit_id;
1805     connection->cmd_operands_fragmented_buffer = command_buffer;
1806     connection->cmd_operands_fragmented_pos = 0;
1807     connection->cmd_operands_fragmented_len = command_len;
1808 
1809     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1810     return ERROR_CODE_SUCCESS;
1811 }
1812