xref: /btstack/src/classic/avrcp_controller.c (revision eebb600bb8b517e7f57c2eff19dd2cdd5728a19d)
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     connection->notifications_to_register |= (1 << event_id);
684 
685     if (!connection->remote_supported_notifications_queried){
686         connection->remote_supported_notifications_suppress_emit_result = true;
687         avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
688         return ERROR_CODE_SUCCESS;
689     }
690     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
691     return ERROR_CODE_SUCCESS;
692 }
693 
694 static uint8_t avrcp_controller_request_abort_continuation(avrcp_connection_t * connection){
695     connection->state = AVCTP_W2_SEND_COMMAND;
696     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
697     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
698     connection->command_type = AVRCP_CTYPE_CONTROL;
699     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
700     connection->subunit_id = AVRCP_SUBUNIT_ID;
701     int pos = 0;
702     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
703     pos += 3;
704     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE; // PDU ID
705     connection->cmd_operands[pos++] = 0;
706     // Parameter Length
707     connection->cmd_operands_length = 8;
708     big_endian_store_16(connection->cmd_operands, pos, 1);
709     pos += 2;
710     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
711     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
712     return ERROR_CODE_SUCCESS;
713 }
714 
715 
716 static uint8_t avrcp_controller_request_continue_response(avrcp_connection_t * connection){
717     connection->state = AVCTP_W2_SEND_COMMAND;
718     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
719     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
720     connection->command_type = AVRCP_CTYPE_CONTROL;
721     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
722     connection->subunit_id = AVRCP_SUBUNIT_ID;
723     int pos = 0;
724     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
725     pos += 3;
726     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE; // PDU ID
727     connection->cmd_operands[pos++] = 0;
728     // Parameter Length
729     connection->cmd_operands_length = 8;
730     big_endian_store_16(connection->cmd_operands, pos, 1);
731     pos += 2;
732     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
733     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
734     return ERROR_CODE_SUCCESS;
735 }
736 
737 static void avrcp_controller_handle_notification(avrcp_connection_t *connection, avrcp_command_type_t ctype, uint8_t *payload, uint16_t size) {
738     if (size < 1) return;
739     uint16_t pos = 0;
740     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) payload[pos++];
741     if ( (event_id < AVRCP_NOTIFICATION_EVENT_FIRST_INDEX) || (event_id > AVRCP_NOTIFICATION_EVENT_LAST_INDEX)){
742         return;
743     }
744 
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 
753             // check if initial value is already sent
754             if ( (connection->initial_status_reported & event_mask) != 0 ){
755                 return;
756             }
757             // emit event only once, initially
758             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_SUCCESS, event_id);
759             connection->initial_status_reported |= event_mask;
760             break;
761         case AVRCP_CTYPE_RESPONSE_CHANGED_STABLE:
762             // received change, event is considered de-registered
763             // we are re-enabling it automatically, if it is not
764             // explicitly disabled
765             connection->notifications_enabled &= reset_event_mask;
766             if (! (connection->notifications_to_deregister & event_mask)){
767                 avrcp_controller_register_notification(connection, event_id);
768             } else {
769                 connection->notifications_to_deregister &= reset_event_mask;
770             }
771             break;
772         default:
773             connection->notifications_to_register &= reset_event_mask;
774             connection->notifications_enabled &= reset_event_mask;
775             connection->notifications_to_deregister &= reset_event_mask;
776             break;
777     }
778 
779     avrcp_controller_emit_notification_for_event_id(connection->avrcp_cid, event_id, ctype, payload + pos, size - pos);
780 }
781 
782 #ifdef ENABLE_AVCTP_FRAGMENTATION
783 static void avctp_reassemble_message(avrcp_connection_t * connection, avctp_packet_type_t packet_type, uint8_t *packet, uint16_t size){
784     // after header (transaction label and packet type)
785     uint16_t pos;
786     uint16_t bytes_to_store;
787 
788     switch (packet_type){
789         case AVCTP_START_PACKET:
790             if (size < 2) return;
791 
792             // store header
793             pos = 0;
794             connection->avctp_reassembly_buffer[pos] = packet[pos];
795             pos++;
796             connection->avctp_reassembly_size = pos;
797 
798             // NOTE: num packets not needed for reassembly, ignoring it does not pose security risk -> no need to store it
799             pos++;
800 
801             // PID in reassembled packet is at offset 1, it will be read later after the avctp_reassemble_message with AVCTP_END_PACKET is called
802 
803             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
804             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
805             connection->avctp_reassembly_size += bytes_to_store;
806             break;
807 
808         case AVCTP_CONTINUE_PACKET:
809         case AVCTP_END_PACKET:
810             if (size < 1) return;
811 
812             // store remaining data, ignore header
813             pos = 1;
814             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
815             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
816             connection->avctp_reassembly_size += bytes_to_store;
817             break;
818 
819         default:
820             return;
821     }
822 }
823 #endif
824 
825 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
826     if (size < 6u) return;
827     uint8_t  pdu_id;
828     avrcp_packet_type_t  vendor_dependent_packet_type;
829 
830     uint16_t pos = 0;
831     connection->last_confirmed_transaction_id = packet[pos] >> 4;
832     avrcp_frame_type_t  frame_type =  (avrcp_frame_type_t)((packet[pos] >> 1) & 0x01);
833     avctp_packet_type_t packet_type = (avctp_packet_type_t)((packet[pos] >> 2) & 0x03);
834     pos++;
835 
836     if (frame_type != AVRCP_RESPONSE_FRAME) return;
837 
838     switch (packet_type){
839         case AVCTP_SINGLE_PACKET:
840             break;
841 
842 #ifdef ENABLE_AVCTP_FRAGMENTATION
843         case AVCTP_START_PACKET:
844         case AVCTP_CONTINUE_PACKET:
845             avctp_reassemble_message(connection, packet_type, packet, size);
846             return;
847 
848         case AVCTP_END_PACKET:
849             avctp_reassemble_message(connection, packet_type, packet, size);
850 
851             packet = connection->avctp_reassembly_buffer;
852             size   = connection->avctp_reassembly_size;
853             break;
854 #endif
855 
856         default:
857             return;
858     }
859 
860     pos += 2; // PID
861 
862     avrcp_command_type_t ctype = (avrcp_command_type_t) packet[pos++];
863 
864 #ifdef ENABLE_LOG_INFO
865     uint8_t byte_value = packet[pos];
866     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (byte_value >> 3);
867     avrcp_subunit_type_t subunit_id   = (avrcp_subunit_type_t) (byte_value & 0x07);
868 #endif
869     pos++;
870 
871     uint8_t opcode = packet[pos++];
872     uint16_t param_length;
873 
874     switch (opcode){
875         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
876             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
877             connection->state = AVCTP_CONNECTION_OPENED;
878 
879 #ifdef ENABLE_LOG_INFO
880             // page, extension code (1)
881             pos++;
882             uint8_t unit_type = packet[pos] >> 3;
883             uint8_t max_subunit_ID = packet[pos] & 0x07;
884             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);
885 #endif
886             break;
887         }
888         case AVRCP_CMD_OPCODE_UNIT_INFO:{
889             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
890             connection->state = AVCTP_CONNECTION_OPENED;
891 
892 #ifdef ENABLE_LOG_INFO
893             // byte value 7 (1)
894             pos++;
895             uint8_t unit_type = packet[pos] >> 3;
896             uint8_t unit = packet[pos] & 0x07;
897             pos++;
898             uint32_t company_id = big_endian_read_24(packet, pos);
899             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,
900                 ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id);
901 #endif
902             break;
903         }
904         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
905 
906             if ((size - pos) < 7) return;
907 
908             // Company ID (3)
909             pos += 3;
910             pdu_id = packet[pos++];
911             vendor_dependent_packet_type = (avrcp_packet_type_t)(packet[pos++] & 0x03);
912             param_length = big_endian_read_16(packet, pos);
913             pos += 2;
914 
915             if ((size - pos) < param_length) return;
916 
917             // handle asynchronous notifications, without changing state
918             if (pdu_id == AVRCP_PDU_ID_REGISTER_NOTIFICATION){
919                 avrcp_controller_handle_notification(connection, ctype, packet + pos, size - pos);
920                 break;
921             }
922 
923             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE){
924                 log_info("AVRCP_CMD_OPCODE_VENDOR_DEPENDENT state %d", connection->state);
925                 return;
926             }
927             connection->state = AVCTP_CONNECTION_OPENED;
928 
929             log_info("VENDOR DEPENDENT response: pdu id 0x%02x, param_length %d, status %s", pdu_id, param_length, avrcp_ctype2str(ctype));
930             switch (pdu_id){
931                 case AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE:{
932                     uint8_t num_attributes = packet[pos++];
933                     int i;
934                     avrcp_repeat_mode_t  repeat_mode =  AVRCP_REPEAT_MODE_INVALID;
935                     avrcp_shuffle_mode_t shuffle_mode = AVRCP_SHUFFLE_MODE_INVALID;
936                     for (i = 0; i < num_attributes; i++){
937                         uint8_t attribute_id    = packet[pos++];
938                         uint8_t value = packet[pos++];
939                         switch (attribute_id){
940                             case 0x02:
941                                 repeat_mode = (avrcp_repeat_mode_t) value;
942                                 break;
943                             case 0x03:
944                                 shuffle_mode = (avrcp_shuffle_mode_t) value;
945                                 break;
946                             default:
947                                 break;
948                         }
949                     }
950                     avrcp_controller_emit_repeat_and_shuffle_mode(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, repeat_mode, shuffle_mode);
951                     break;
952                 }
953 
954                 case AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE:{
955                     uint16_t offset = 0;
956                     uint8_t event[6];
957                     event[offset++] = HCI_EVENT_AVRCP_META;
958                     event[offset++] = sizeof(event) - 2;
959                     event[offset++] = AVRCP_SUBEVENT_PLAYER_APPLICATION_VALUE_RESPONSE;
960                     little_endian_store_16(event, offset, connection->avrcp_cid);
961                     offset += 2;
962                     event[offset++] = ctype;
963                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
964                     break;
965                 }
966 
967                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME:{
968                     uint16_t offset = 0;
969                     uint8_t event[7];
970                     event[offset++] = HCI_EVENT_AVRCP_META;
971                     event[offset++] = sizeof(event) - 2;
972                     event[offset++] = AVRCP_SUBEVENT_SET_ABSOLUTE_VOLUME_RESPONSE;
973                     little_endian_store_16(event, offset, connection->avrcp_cid);
974                     offset += 2;
975                     event[offset++] = ctype;
976                     event[offset++] = packet[pos++];
977                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
978                     break;
979                 }
980 
981                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
982                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos++];
983                     uint8_t capability_count = 0;
984                     if (param_length > 1){
985                         capability_count = packet[pos++];
986                     }
987                     uint16_t i;
988                     uint16_t offset = 0;
989                     uint8_t event[10];
990 
991                     switch (capability_id){
992 
993                         case AVRCP_CAPABILITY_ID_COMPANY:
994                             for (i = 0; (i < capability_count) && ((size - pos) >= 3); i++){
995                                 uint32_t company_id = big_endian_read_24(packet, pos);
996                                 pos += 3;
997                                 log_info("  0x%06" PRIx32 ", ", company_id);
998 
999                                 offset = 0;
1000                                 event[offset++] = HCI_EVENT_AVRCP_META;
1001                                 event[offset++] = sizeof(event) - 2;
1002                                 event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID;
1003                                 little_endian_store_16(event, offset, connection->avrcp_cid);
1004                                 offset += 2;
1005                                 event[offset++] = ctype;
1006                                 event[offset++] = 0;
1007                                 little_endian_store_24(event, offset, company_id);
1008                                 offset += 3;
1009                                 (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1010                             }
1011 
1012                             offset = 0;
1013                             event[offset++] = HCI_EVENT_AVRCP_META;
1014                             event[offset++] = sizeof(event) - 2;
1015                             event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID_DONE;
1016                             little_endian_store_16(event, offset, connection->avrcp_cid);
1017                             offset += 2;
1018                             event[offset++] = ctype;
1019                             event[offset++] = 0;
1020                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
1021                             break;
1022 
1023                         case AVRCP_CAPABILITY_ID_EVENT:
1024                             for (i = 0; (i < capability_count) && ((size - pos) >= 1); i++){
1025                                 uint8_t event_id = packet[pos++];
1026                                 connection->remote_supported_notifications |= (1 << event_id);
1027                             }
1028 
1029                             // if the get supported events query is triggered by avrcp_controller_enable_notification call,
1030                             // avrcp_controller_emit_supported_events should be suppressed
1031                             if (connection->remote_supported_notifications_suppress_emit_result){
1032                                 connection->remote_supported_notifications_suppress_emit_result = false;
1033                                 // also, notification might not be supported
1034                                 // if so, emit AVRCP_SUBEVENT_ENABLE_NOTIFICATION_COMPLETE event to app,
1035                                 // and update notifications_to_register bitmap
1036                                 for (i = (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; i < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; i++){
1037                                     if ((connection->notifications_to_register & (1<<i)) != 0){
1038                                         if ((connection->remote_supported_notifications & (1<<i)) == 0){
1039                                             avrcp_controller_emit_notification_complete(connection, ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE, i);
1040                                             connection->notifications_to_register &= ~(1 << i);
1041                                         }
1042                                     }
1043                                 }
1044                                 break;
1045                             }
1046                             // supported events are emitted only if the get supported events query
1047                             // is triggered by avrcp_controller_get_supported_events call
1048                             avrcp_controller_emit_supported_events(connection);
1049                             break;
1050 
1051                         default:
1052                             // ignore
1053                             break;
1054                     }
1055                     break;
1056                 }
1057 
1058                 case AVRCP_PDU_ID_GET_PLAY_STATUS:{
1059                     uint32_t song_length = big_endian_read_32(packet, pos);
1060                     pos += 4;
1061                     uint32_t song_position = big_endian_read_32(packet, pos);
1062                     pos += 4;
1063                     uint8_t play_status = packet[pos];
1064 
1065                     uint8_t event[15];
1066                     int offset = 0;
1067                     event[offset++] = HCI_EVENT_AVRCP_META;
1068                     event[offset++] = sizeof(event) - 2;
1069                     event[offset++] = AVRCP_SUBEVENT_PLAY_STATUS;
1070                     little_endian_store_16(event, offset, connection->avrcp_cid);
1071                     offset += 2;
1072                     event[offset++] = ctype;
1073                     little_endian_store_32(event, offset, song_length);
1074                     offset += 4;
1075                     little_endian_store_32(event, offset, song_position);
1076                     offset += 4;
1077                     event[offset++] = play_status;
1078                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1079                     break;
1080                 }
1081 
1082                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
1083                     switch (vendor_dependent_packet_type){
1084                         case AVRCP_START_PACKET:
1085                         case AVRCP_SINGLE_PACKET:
1086                             avrcp_parser_reset(connection);
1087                             connection->list_size = param_length;
1088                             connection->num_attributes = packet[pos++];
1089 
1090                             avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1091                             if (vendor_dependent_packet_type == AVRCP_START_PACKET){
1092                                 avrcp_controller_request_continue_response(connection);
1093                             }
1094                             break;
1095                         case AVRCP_CONTINUE_PACKET:
1096                         case AVRCP_END_PACKET:
1097                             connection->num_received_fragments++;
1098 
1099                             if (connection->num_received_fragments < connection->max_num_fragments){
1100                                 avrcp_controller_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
1101 
1102                                 if (vendor_dependent_packet_type == AVRCP_CONTINUE_PACKET){
1103                                     avrcp_controller_request_continue_response(connection);
1104                                 }
1105                             } else {
1106                                 avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 1);
1107                                 avrcp_parser_reset(connection);
1108                                 avrcp_controller_request_abort_continuation(connection);
1109                             }
1110                             break;
1111                         default:
1112                             // TODO check
1113                             btstack_assert(false);
1114                             break;
1115                     }
1116                 }
1117                 default:
1118                     break;
1119             }
1120             break;
1121         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
1122             if ((size - pos) < 1) return;
1123             uint8_t operation_id = packet[pos++];
1124             switch (connection->state){
1125                 case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1126                     // trigger release for simple command:
1127                     if (!connection->press_and_hold_cmd_active){
1128                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1129                         break;
1130                     }
1131                     // for press and hold, send release if it just has been requested, otherwise, wait for next repeat
1132                     if (connection->press_and_hold_cmd_release){
1133                         connection->press_and_hold_cmd_release = false;
1134                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
1135                     } else {
1136                         connection->state = AVCTP_W4_STOP;
1137                     }
1138                     break;
1139                 case AVCTP_W2_RECEIVE_RESPONSE:
1140                     connection->state = AVCTP_CONNECTION_OPENED;
1141                     break;
1142                 default:
1143                     break;
1144             }
1145             if (connection->state == AVCTP_W4_STOP){
1146                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_START, connection->avrcp_cid, ctype, operation_id);
1147             }
1148             if (connection->state == AVCTP_CONNECTION_OPENED) {
1149                 // RELEASE response
1150                 operation_id = operation_id & 0x7F;
1151                 avrcp_controller_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_COMPLETE, connection->avrcp_cid, ctype, operation_id);
1152             }
1153             if (connection->state == AVCTP_W2_SEND_RELEASE_COMMAND){
1154                 // PRESS response
1155                 avrcp_controller_request_pass_through_release_control_cmd(connection);
1156             }
1157             break;
1158         }
1159         default:
1160             break;
1161     }
1162 
1163     // trigger pending notification reqistrations
1164     if ((connection->state == AVCTP_CONNECTION_OPENED) && connection->notifications_to_register){
1165         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1166     }
1167 }
1168 
1169 static void avrcp_controller_handle_can_send_now(avrcp_connection_t * connection){
1170     switch (connection->state){
1171         case AVCTP_W2_SEND_PRESS_COMMAND:
1172             connection->state = AVCTP_W2_RECEIVE_PRESS_RESPONSE;
1173             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
1174             return;
1175         case AVCTP_W2_SEND_COMMAND:
1176         case AVCTP_W2_SEND_RELEASE_COMMAND:
1177             connection->state = AVCTP_W2_RECEIVE_RESPONSE;
1178             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
1179             return;
1180         case AVCTP_W2_SEND_FRAGMENTED_COMMAND:
1181             if (connection->cmd_operands_fragmented_pos == 0){
1182                  avrcp_send_cmd(connection, AVRCP_START_PACKET);
1183                  avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1184             } else {
1185                 if ((connection->cmd_operands_fragmented_len - connection->cmd_operands_fragmented_pos) > avrcp_get_max_payload_size_for_packet_type(AVRCP_CONTINUE_PACKET)){
1186                      avrcp_send_cmd(connection, AVRCP_CONTINUE_PACKET);
1187                      avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1188                  } else {
1189                     connection->state = AVCTP_W2_RECEIVE_RESPONSE;
1190                     avrcp_send_cmd(connection, AVRCP_END_PACKET);
1191                  }
1192             }
1193             return;
1194         default:
1195             break;
1196     }
1197     // send register notification if queued
1198     if (connection->notifications_to_register != 0){
1199         uint8_t event_id;
1200         for (event_id = (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t)AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
1201             if (connection->notifications_to_register & (1<<event_id)){
1202                 connection->notifications_to_register &= ~ (1 << event_id);
1203                 avrcp_send_register_notification(connection, event_id);
1204                 return;
1205             }
1206         }
1207     }
1208 }
1209 
1210 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1211     avrcp_connection_t * connection;
1212 
1213     switch (packet_type) {
1214         case L2CAP_DATA_PACKET:
1215             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1216             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1217             break;
1218 
1219         case HCI_EVENT_PACKET:
1220             switch (hci_event_packet_get_type(packet)){
1221                 case L2CAP_EVENT_CAN_SEND_NOW:
1222                     connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
1223                     avrcp_controller_handle_can_send_now(connection);
1224                     break;
1225             default:
1226                 break;
1227         }
1228         default:
1229             break;
1230     }
1231 }
1232 
1233 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){
1234     avrcp_create_sdp_record(1, service, service_record_handle, avrcp_controller_supports_browsing(supported_features), supported_features, service_name, service_provider_name);
1235 }
1236 
1237 void avrcp_controller_init(void){
1238     avrcp_controller_context.role = AVRCP_CONTROLLER;
1239     avrcp_controller_context.packet_handler = avrcp_controller_packet_handler;
1240     avrcp_register_controller_packet_handler(&avrcp_controller_packet_handler);
1241 }
1242 
1243 void avrcp_controller_deinit(void){
1244     memset(&avrcp_controller_context, 0, sizeof(avrcp_context_t));
1245 }
1246 
1247 void avrcp_controller_register_packet_handler(btstack_packet_handler_t callback){
1248     btstack_assert(callback != NULL);
1249     avrcp_controller_context.avrcp_callback = callback;
1250 }
1251 
1252 
1253 uint8_t avrcp_controller_play(uint16_t avrcp_cid){
1254     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1255 }
1256 
1257 uint8_t avrcp_controller_stop(uint16_t avrcp_cid){
1258     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1259 }
1260 
1261 uint8_t avrcp_controller_pause(uint16_t avrcp_cid){
1262     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1263 }
1264 
1265 uint8_t avrcp_controller_forward(uint16_t avrcp_cid){
1266     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1267 }
1268 
1269 uint8_t avrcp_controller_backward(uint16_t avrcp_cid){
1270     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1271 }
1272 
1273 uint8_t avrcp_controller_volume_up(uint16_t avrcp_cid){
1274     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1275 }
1276 
1277 uint8_t avrcp_controller_volume_down(uint16_t avrcp_cid){
1278     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1279 }
1280 
1281 uint8_t avrcp_controller_mute(uint16_t avrcp_cid){
1282     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1283 }
1284 
1285 uint8_t avrcp_controller_skip(uint16_t avrcp_cid){
1286     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_SKIP, 0);
1287 }
1288 
1289 uint8_t avrcp_controller_fast_forward(uint16_t avrcp_cid){
1290     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1291 }
1292 
1293 uint8_t avrcp_controller_rewind(uint16_t avrcp_cid){
1294     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1295 }
1296 
1297 /* start continuous cmds */
1298 
1299 uint8_t avrcp_controller_start_press_and_hold_cmd(uint16_t avrcp_cid, avrcp_operation_id_t operation_id){
1300     return request_continuous_pass_through_press_control_cmd(avrcp_cid, operation_id, 0);
1301 }
1302 
1303 uint8_t avrcp_controller_press_and_hold_play(uint16_t avrcp_cid){
1304     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1305 }
1306 uint8_t avrcp_controller_press_and_hold_stop(uint16_t avrcp_cid){
1307     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1308 }
1309 uint8_t avrcp_controller_press_and_hold_pause(uint16_t avrcp_cid){
1310     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1311 }
1312 uint8_t avrcp_controller_press_and_hold_forward(uint16_t avrcp_cid){
1313     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1314 }
1315 uint8_t avrcp_controller_press_and_hold_backward(uint16_t avrcp_cid){
1316     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1317 }
1318 uint8_t avrcp_controller_press_and_hold_fast_forward(uint16_t avrcp_cid){
1319     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1320 }
1321 uint8_t avrcp_controller_press_and_hold_rewind(uint16_t avrcp_cid){
1322     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1323 }
1324 uint8_t avrcp_controller_press_and_hold_volume_up(uint16_t avrcp_cid){
1325     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1326 }
1327 uint8_t avrcp_controller_press_and_hold_volume_down(uint16_t avrcp_cid){
1328     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1329 }
1330 uint8_t avrcp_controller_press_and_hold_mute(uint16_t avrcp_cid){
1331     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1332 }
1333 
1334 /* stop continuous cmds */
1335 uint8_t avrcp_controller_release_press_and_hold_cmd(uint16_t avrcp_cid){
1336     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1337     if (!connection){
1338         log_error("avrcp_stop_play: could not find a connection.");
1339         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1340     }
1341 
1342     switch (connection->state){
1343         // respond when we receive response for (repeated) press command
1344         case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
1345             connection->press_and_hold_cmd_release = true;
1346             break;
1347 
1348         // release already sent or on the way, nothing to do
1349         case AVCTP_W2_RECEIVE_RESPONSE:
1350         case AVCTP_W2_SEND_RELEASE_COMMAND:
1351             break;
1352 
1353         // about to send next repeated press command or wait for it -> release right away
1354         case AVCTP_W2_SEND_PRESS_COMMAND:
1355         case AVCTP_W4_STOP:
1356             return avrcp_controller_request_pass_through_release_control_cmd(connection);
1357 
1358         // otherwise reject request
1359         default:
1360             return ERROR_CODE_COMMAND_DISALLOWED;
1361     }
1362     return ERROR_CODE_SUCCESS;
1363 }
1364 
1365 uint8_t avrcp_controller_enable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1366     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1367     if (!connection){
1368         log_error("avrcp_get_play_status: could not find a connection.");
1369         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1370     }
1371     return avrcp_controller_register_notification(connection, event_id);
1372 }
1373 
1374 uint8_t avrcp_controller_disable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1375     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1376     if (!connection){
1377         log_error("avrcp_get_play_status: could not find a connection.");
1378         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1379     }
1380     connection->notifications_to_deregister |= (1 << event_id);
1381     return ERROR_CODE_SUCCESS;
1382 }
1383 
1384 uint8_t avrcp_controller_unit_info(uint16_t avrcp_cid){
1385     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1386     if (!connection){
1387         log_error("avrcp_unit_info: could not find a connection.");
1388         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1389     }
1390     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1391     connection->state = AVCTP_W2_SEND_COMMAND;
1392 
1393     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1394     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
1395     connection->command_type = AVRCP_CTYPE_STATUS;
1396     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
1397     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
1398     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
1399     connection->cmd_operands_length = 5;
1400     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1401     return ERROR_CODE_SUCCESS;
1402 }
1403 
1404 uint8_t avrcp_controller_subunit_info(uint16_t avrcp_cid){
1405     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1406     if (!connection){
1407         log_error("avrcp_unit_info: could not find a connection.");
1408         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1409     }
1410     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1411     connection->state = AVCTP_W2_SEND_COMMAND;
1412 
1413     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1414     connection->command_opcode = AVRCP_CMD_OPCODE_SUBUNIT_INFO;
1415     connection->command_type = AVRCP_CTYPE_STATUS;
1416     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
1417     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
1418     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
1419     connection->cmd_operands[0] = 7; // page: 0, extention_code: 7
1420     connection->cmd_operands_length = 5;
1421     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1422     return ERROR_CODE_SUCCESS;
1423 }
1424 
1425 uint8_t avrcp_controller_get_supported_company_ids(uint16_t avrcp_cid){
1426     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1427     if (!connection){
1428         log_error("avrcp_get_capabilities: could not find a connection.");
1429         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1430     }
1431     if (connection->state != AVCTP_CONNECTION_OPENED){
1432         return ERROR_CODE_COMMAND_DISALLOWED;
1433     }
1434     avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_COMPANY);
1435     return ERROR_CODE_SUCCESS;
1436 }
1437 
1438 uint8_t avrcp_controller_get_supported_events(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 
1448     if (!connection->remote_supported_notifications_queried){
1449         connection->remote_supported_notifications_queried = true;
1450         avrcp_controller_get_capabilities_for_connection(connection, AVRCP_CAPABILITY_ID_EVENT);
1451         return ERROR_CODE_SUCCESS;
1452     }
1453 
1454     avrcp_controller_emit_supported_events(connection);
1455     return ERROR_CODE_SUCCESS;
1456 }
1457 
1458 uint8_t avrcp_controller_get_play_status(uint16_t avrcp_cid){
1459     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1460     if (!connection){
1461         log_error("avrcp_get_play_status: could not find a connection.");
1462         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1463     }
1464     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1465     connection->state = AVCTP_W2_SEND_COMMAND;
1466     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1467     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1468     connection->command_type = AVRCP_CTYPE_STATUS;
1469     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1470     connection->subunit_id = AVRCP_SUBUNIT_ID;
1471     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1472     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_PLAY_STATUS;
1473     connection->cmd_operands[4] = 0;                     // reserved(upper 6) | packet_type -> 0
1474     big_endian_store_16(connection->cmd_operands, 5, 0); // parameter length
1475     connection->cmd_operands_length = 7;
1476     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1477     return ERROR_CODE_SUCCESS;
1478 }
1479 
1480 uint8_t avrcp_controller_set_addressed_player(uint16_t avrcp_cid, uint16_t addressed_player_id){
1481     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1482     if (!connection){
1483         log_error("avrcp_get_capabilities: could not find a connection.");
1484         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1485     }
1486     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1487     connection->state = AVCTP_W2_SEND_COMMAND;
1488 
1489     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1490     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1491     connection->command_type = AVRCP_CTYPE_CONTROL;
1492     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1493     connection->subunit_id = AVRCP_SUBUNIT_ID;
1494     int pos = 0;
1495     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1496     pos += 3;
1497     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ADDRESSED_PLAYER; // PDU ID
1498     connection->cmd_operands[pos++] = 0;
1499 
1500     // Parameter Length
1501     big_endian_store_16(connection->cmd_operands, pos, 2);
1502     pos += 2;
1503 
1504     big_endian_store_16(connection->cmd_operands, pos, addressed_player_id);
1505     pos += 2;
1506 
1507     connection->cmd_operands_length = pos;
1508     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1509     return ERROR_CODE_SUCCESS;
1510 }
1511 
1512 uint8_t avrcp_controller_get_element_attributes(uint16_t avrcp_cid, uint8_t num_attributes, avrcp_media_attribute_id_t * attributes){
1513     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1514     if (!connection){
1515         log_error("avrcp_get_capabilities: could not find a connection.");
1516         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1517     }
1518 
1519     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1520 
1521     if (num_attributes >= AVRCP_MEDIA_ATTR_RESERVED) {
1522         return ERROR_CODE_INVALID_HCI_COMMAND_PARAMETERS;
1523     }
1524     connection->state = AVCTP_W2_SEND_COMMAND;
1525 
1526     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1527     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1528     connection->command_type = AVRCP_CTYPE_STATUS;
1529     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1530     connection->subunit_id = AVRCP_SUBUNIT_ID;
1531     int pos = 0;
1532     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1533     pos += 3;
1534     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES; // PDU ID
1535     connection->cmd_operands[pos++] = 0;
1536 
1537     // Parameter Length
1538     big_endian_store_16(connection->cmd_operands, pos, 9);
1539     pos += 2;
1540 
1541     // write 8 bytes value
1542     memset(connection->cmd_operands + pos, 0, 8); // identifier: PLAYING
1543     pos += 8;
1544 
1545     connection->cmd_operands[pos++] = num_attributes; // attribute count, if 0 get all attributes
1546 
1547     int i;
1548     for (i = 0; i < num_attributes; i++){
1549         // every attribute is 4 bytes long
1550         big_endian_store_32(connection->cmd_operands, pos, attributes[i]);
1551         pos += 4;
1552     }
1553 
1554     connection->cmd_operands_length = pos;
1555     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1556     return ERROR_CODE_SUCCESS;
1557 }
1558 
1559 uint8_t avrcp_controller_get_now_playing_info(uint16_t avrcp_cid){
1560     return avrcp_controller_get_element_attributes(avrcp_cid, 0, NULL);
1561 }
1562 
1563 uint8_t avrcp_controller_set_absolute_volume(uint16_t avrcp_cid, uint8_t volume){
1564      avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1565     if (!connection){
1566         log_error("avrcp_get_capabilities: could not find a connection.");
1567         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1568     }
1569 
1570     //
1571     // allow sending of multiple set abs volume commands without waiting for response
1572     //
1573     uint8_t status = ERROR_CODE_COMMAND_DISALLOWED;
1574     switch (connection->state){
1575         case AVCTP_CONNECTION_OPENED:
1576             status = ERROR_CODE_SUCCESS;
1577             break;
1578         case AVCTP_W2_RECEIVE_RESPONSE:
1579             // - is pending response also set abs volume
1580             if (connection->command_opcode  != AVRCP_CMD_OPCODE_VENDOR_DEPENDENT) break;
1581             if (connection->command_type    != AVRCP_CTYPE_CONTROL)               break;
1582             if (connection->subunit_type    != AVRCP_SUBUNIT_TYPE_PANEL)          break;
1583             if (connection->subunit_id      != AVRCP_SUBUNIT_ID)                  break;
1584             if (connection->cmd_operands[3] != AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME)  break;
1585             // - is next transaction id valid in window
1586             if (avrcp_controller_is_transaction_id_valid(connection, avrcp_controller_calc_next_transaction_label(connection->transaction_id_counter)) == false) break;
1587             status = ERROR_CODE_SUCCESS;
1588             break;
1589         default:
1590             break;
1591     }
1592     if (status != ERROR_CODE_SUCCESS) return status;
1593 
1594     connection->state = AVCTP_W2_SEND_COMMAND;
1595 
1596     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1597     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1598     connection->command_type = AVRCP_CTYPE_CONTROL;
1599     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1600     connection->subunit_id = AVRCP_SUBUNIT_ID;
1601     int pos = 0;
1602     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1603     pos += 3;
1604     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME; // PDU ID
1605     connection->cmd_operands[pos++] = 0;
1606 
1607     // Parameter Length
1608     big_endian_store_16(connection->cmd_operands, pos, 1);
1609     pos += 2;
1610     connection->cmd_operands[pos++] = volume;
1611 
1612     connection->cmd_operands_length = pos;
1613     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1614     return ERROR_CODE_SUCCESS;
1615 }
1616 
1617 uint8_t avrcp_controller_query_shuffle_and_repeat_modes(uint16_t avrcp_cid){
1618     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1619     if (!connection){
1620         log_error("avrcp_get_capabilities: could not find a connection.");
1621         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1622     }
1623     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1624     connection->state = AVCTP_W2_SEND_COMMAND;
1625 
1626     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1627     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1628     connection->command_type = AVRCP_CTYPE_STATUS;
1629     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1630     connection->subunit_id = AVRCP_SUBUNIT_ID;
1631     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1632     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE; // PDU ID
1633     connection->cmd_operands[4] = 0;
1634     big_endian_store_16(connection->cmd_operands, 5, 5); // parameter length
1635     connection->cmd_operands[7] = 4;                     // NumPlayerApplicationSettingAttributeID
1636     // PlayerApplicationSettingAttributeID1 AVRCP Spec, Appendix F, 133
1637     connection->cmd_operands[8]  = 0x01;    // equalizer  (1-OFF, 2-ON)
1638     connection->cmd_operands[9]  = 0x02;    // repeat     (1-off, 2-single track, 3-all tracks, 4-group repeat)
1639     connection->cmd_operands[10] = 0x03;    // shuffle    (1-off, 2-all tracks, 3-group shuffle)
1640     connection->cmd_operands[11] = 0x04;    // scan       (1-off, 2-all tracks, 3-group scan)
1641     connection->cmd_operands_length = 12;
1642     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1643     return ERROR_CODE_SUCCESS;
1644 }
1645 
1646 static uint8_t avrcp_controller_set_current_player_application_setting_value(uint16_t avrcp_cid, uint8_t attr_id, uint8_t attr_value){
1647     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1648     if (!connection){
1649         log_error("avrcp_get_capabilities: could not find a connection.");
1650         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1651     }
1652     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1653     connection->state = AVCTP_W2_SEND_COMMAND;
1654 
1655     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1656     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1657     connection->command_type = AVRCP_CTYPE_CONTROL;
1658     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1659     connection->subunit_id = AVRCP_SUBUNIT_ID;
1660     int pos = 0;
1661     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1662     pos += 3;
1663     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE; // PDU ID
1664     connection->cmd_operands[pos++] = 0;
1665     // Parameter Length
1666     big_endian_store_16(connection->cmd_operands, pos, 3);
1667     pos += 2;
1668     connection->cmd_operands[pos++] = 2;
1669     connection->cmd_operands_length = pos;
1670     connection->cmd_operands[pos++]  = attr_id;
1671     connection->cmd_operands[pos++]  = attr_value;
1672     connection->cmd_operands_length = pos;
1673     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1674     return ERROR_CODE_SUCCESS;
1675 }
1676 
1677 uint8_t avrcp_controller_set_shuffle_mode(uint16_t avrcp_cid, avrcp_shuffle_mode_t mode){
1678     if ((mode < AVRCP_SHUFFLE_MODE_OFF) || (mode > AVRCP_SHUFFLE_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1679     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x03, mode);
1680 }
1681 
1682 uint8_t avrcp_controller_set_repeat_mode(uint16_t avrcp_cid, avrcp_repeat_mode_t mode){
1683     if ((mode < AVRCP_REPEAT_MODE_OFF) || (mode > AVRCP_REPEAT_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1684     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x02, mode);
1685 }
1686 
1687 uint8_t avrcp_controller_play_item_for_scope(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1688     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1689     if (!connection){
1690         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1691         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1692     }
1693     if (connection->state != AVCTP_CONNECTION_OPENED){
1694         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1695         return ERROR_CODE_COMMAND_DISALLOWED;
1696     }
1697     connection->state = AVCTP_W2_SEND_COMMAND;
1698 
1699     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1700     connection->command_type = AVRCP_CTYPE_CONTROL;
1701     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1702     connection->subunit_id = AVRCP_SUBUNIT_ID;
1703     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1704     int pos = 0;
1705     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1706     pos += 3;
1707     connection->cmd_operands[pos++] = AVRCP_PDU_ID_PLAY_ITEM; // PDU ID
1708     // reserved
1709     connection->cmd_operands[pos++] = 0;
1710     // Parameter Length
1711     big_endian_store_16(connection->cmd_operands, pos, 11);
1712     pos += 2;
1713     connection->cmd_operands[pos++]  = scope;
1714     memset(&connection->cmd_operands[pos], 0, 8);
1715     if (uid){
1716         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1717     }
1718     pos += 8;
1719     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1720     pos += 2;
1721     connection->cmd_operands_length = pos;
1722 
1723     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1724     return ERROR_CODE_SUCCESS;
1725 }
1726 
1727 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){
1728     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1729     if (!connection){
1730         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1731         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1732     }
1733     if (connection->state != AVCTP_CONNECTION_OPENED){
1734         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1735         return ERROR_CODE_COMMAND_DISALLOWED;
1736     }
1737     connection->state = AVCTP_W2_SEND_COMMAND;
1738 
1739     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1740     connection->command_type = AVRCP_CTYPE_CONTROL;
1741     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1742     connection->subunit_id = AVRCP_SUBUNIT_ID;
1743     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1744     int pos = 0;
1745     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1746     pos += 3;
1747     connection->cmd_operands[pos++] = AVRCP_PDU_ID_ADD_TO_NOW_PLAYING; // PDU ID
1748     // reserved
1749     connection->cmd_operands[pos++] = 0;
1750     // Parameter Length
1751     big_endian_store_16(connection->cmd_operands, pos, 11);
1752     pos += 2;
1753     connection->cmd_operands[pos++]  = scope;
1754     memset(&connection->cmd_operands[pos], 0, 8);
1755     if (uid){
1756         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1757     }
1758     pos += 8;
1759     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1760     pos += 2;
1761     connection->cmd_operands_length = pos;
1762 
1763     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1764     return ERROR_CODE_SUCCESS;
1765 }
1766 
1767 uint8_t avrcp_controller_set_max_num_fragments(uint16_t avrcp_cid, uint8_t max_num_fragments){
1768     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1769     if (!connection){
1770         log_error("avrcp_controller_play_item: could not find a connection.");
1771         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1772     }
1773     connection->max_num_fragments = max_num_fragments;
1774     return ERROR_CODE_SUCCESS;
1775 }
1776 
1777 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){
1778     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1779     if (!connection){
1780         log_error("avrcp_controller_play_item: could not find a connection.");
1781         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1782     }
1783 
1784     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1785     connection->state = AVCTP_W2_SEND_FRAGMENTED_COMMAND;
1786 
1787     connection->transaction_id = avrcp_controller_get_next_transaction_label(connection);
1788     connection->command_opcode = command_opcode;
1789     connection->command_type = command_type;
1790     connection->subunit_type = subunit_type;
1791     connection->subunit_id = subunit_id;
1792     connection->cmd_operands_fragmented_buffer = command_buffer;
1793     connection->cmd_operands_fragmented_pos = 0;
1794     connection->cmd_operands_fragmented_len = command_len;
1795 
1796     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1797     return ERROR_CODE_SUCCESS;
1798 }
1799