xref: /btstack/src/classic/avrcp_controller.c (revision c6cd1191c961ed2ed3f162c1049c1fe365b31c08)
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 "btstack.h"
45 #include "classic/avrcp.h"
46 #include "classic/avrcp_controller.h"
47 
48 // made public in avrcp_controller.h
49 avrcp_context_t avrcp_controller_context;
50 
51 static int avrcp_controller_supports_browsing(uint16_t controller_supported_features){
52     return controller_supported_features & AVRCP_FEATURE_MASK_BROWSING;
53 }
54 
55 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){
56     avrcp_create_sdp_record(1, service, service_record_handle, avrcp_controller_supports_browsing(supported_features), supported_features, service_name, service_provider_name);
57 }
58 
59 static void avrcp_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){
60     btstack_assert(callback != NULL);
61 
62     uint8_t event[8];
63     int pos = 0;
64     event[pos++] = HCI_EVENT_AVRCP_META;
65     event[pos++] = sizeof(event) - 2;
66     event[pos++] = AVRCP_SUBEVENT_SHUFFLE_AND_REPEAT_MODE;
67     little_endian_store_16(event, pos, avrcp_cid);
68     pos += 2;
69     event[pos++] = ctype;
70     event[pos++] = repeat_mode;
71     event[pos++] = shuffle_mode;
72     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
73 }
74 
75 static void avrcp_emit_operation_status(btstack_packet_handler_t callback, uint8_t subevent, uint16_t avrcp_cid, uint8_t ctype, uint8_t operation_id){
76     btstack_assert(callback != NULL);
77 
78     uint8_t event[7];
79     int pos = 0;
80     event[pos++] = HCI_EVENT_AVRCP_META;
81     event[pos++] = sizeof(event) - 2;
82     event[pos++] = subevent;
83     little_endian_store_16(event, pos, avrcp_cid);
84     pos += 2;
85     event[pos++] = ctype;
86     event[pos++] = operation_id;
87     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
88 }
89 
90 static void avrcp_press_and_hold_timeout_handler(btstack_timer_source_t * timer){
91     UNUSED(timer);
92     avrcp_connection_t * connection = (avrcp_connection_t*) btstack_run_loop_get_timer_context(timer);
93     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
94     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
95     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
96     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
97 }
98 
99 static void avrcp_press_and_hold_timer_start(avrcp_connection_t * connection){
100     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
101     btstack_run_loop_set_timer_handler(&connection->press_and_hold_cmd_timer, avrcp_press_and_hold_timeout_handler);
102     btstack_run_loop_set_timer_context(&connection->press_and_hold_cmd_timer, connection);
103     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
104     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
105 }
106 
107 static void avrcp_press_and_hold_timer_stop(avrcp_connection_t * connection){
108     connection->continuous_fast_forward_cmd = 0;
109     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
110 }
111 
112 static uint8_t request_pass_through_release_control_cmd(avrcp_connection_t * connection){
113     connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
114     if (connection->continuous_fast_forward_cmd){
115         avrcp_press_and_hold_timer_stop(connection);
116     }
117     connection->cmd_operands[0] = 0x80 | connection->cmd_operands[0];
118     connection->transaction_label++;
119     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
120     return ERROR_CODE_SUCCESS;
121 }
122 
123 static inline uint8_t request_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed, uint8_t continuous_fast_forward_cmd){
124     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
125     if (!connection){
126         log_error("avrcp: could not find a connection. avrcp cid 0x%02x", avrcp_cid);
127         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
128     }
129 
130     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
131     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
132     connection->command_opcode =  AVRCP_CMD_OPCODE_PASS_THROUGH;
133     connection->command_type = AVRCP_CTYPE_CONTROL;
134     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
135     connection->subunit_id =   AVRCP_SUBUNIT_ID;
136     connection->cmd_operands_length = 0;
137 
138     connection->continuous_fast_forward_cmd = continuous_fast_forward_cmd;
139     connection->cmd_operands_length = 2;
140     connection->cmd_operands[0] = opid;
141     if (playback_speed > 0){
142         connection->cmd_operands[2] = playback_speed;
143         connection->cmd_operands_length++;
144     }
145     connection->cmd_operands[1] = connection->cmd_operands_length - 2;
146 
147     if (connection->continuous_fast_forward_cmd){
148         avrcp_press_and_hold_timer_start(connection);
149     }
150 
151     connection->transaction_label++;
152     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
153     return ERROR_CODE_SUCCESS;
154 }
155 
156 static uint8_t request_single_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
157     return request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, 0);
158 }
159 
160 static uint8_t request_continuous_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
161     return request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, 1);
162 }
163 
164 #define AVRCP_CMD_BUFFER_SIZE 30
165 static uint16_t avrcp_get_max_payload_size_for_packet_type(avrcp_packet_type_t packet_type){
166     switch (packet_type){
167         case AVRCP_SINGLE_PACKET:
168             return AVRCP_CMD_BUFFER_SIZE - 3;
169         case AVRCP_START_PACKET:
170             return AVRCP_CMD_BUFFER_SIZE - 4;
171         case AVRCP_CONTINUE_PACKET:
172         case AVRCP_END_PACKET:
173             return AVRCP_CMD_BUFFER_SIZE - 1;
174     }
175     return 0;
176 }
177 
178 static int avrcp_send_cmd(avrcp_connection_t * connection, avrcp_packet_type_t packet_type){
179     uint8_t command[AVRCP_CMD_BUFFER_SIZE];
180     int pos = 0;
181 
182     // non-fragmented: transport header (1) + PID (2)
183     // fragmented:     transport header (1) + num packets (1) + PID (2)
184 
185     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
186     command[pos++] = (connection->transaction_label << 4) | (packet_type << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
187 
188     if (packet_type == AVRCP_START_PACKET){
189         // num packets: (3 bytes overhead (PID, num packets) + command) / (MTU - transport header).
190         // to get number of packets using integer division, we subtract 1 from the data e.g. len = 5, packet size 5 => need 1 packet
191         command[pos++] = ((connection->cmd_operands_fragmented_len + 3 - 1) / (AVRCP_CMD_BUFFER_SIZE - 1)) + 1;
192     }
193 
194     if ((packet_type == AVRCP_SINGLE_PACKET) || (packet_type == AVRCP_START_PACKET)){
195         // Profile IDentifier (PID)
196         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
197         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
198 
199         // command_type
200         command[pos++] = connection->command_type;
201         // subunit_type | subunit ID
202         command[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
203         // opcode
204         command[pos++] = (uint8_t)connection->command_opcode;
205     }
206 
207     if (packet_type == AVRCP_SINGLE_PACKET){
208         // operands
209         (void)memcpy(command + pos, connection->cmd_operands,
210                      connection->cmd_operands_length);
211         pos += connection->cmd_operands_length;
212     } else {
213         uint16_t bytes_free = AVRCP_CMD_BUFFER_SIZE - pos;
214         uint16_t bytes_to_store = connection->cmd_operands_fragmented_len-connection->cmd_operands_fragmented_pos;
215         uint16_t bytes_to_copy = btstack_min(bytes_to_store, bytes_free);
216         (void)memcpy(command + pos,
217                      &connection->cmd_operands_fragmented_buffer[connection->cmd_operands_fragmented_pos],
218                      bytes_to_copy);
219         pos += bytes_to_copy;
220         connection->cmd_operands_fragmented_pos += bytes_to_copy;
221     }
222 
223     return l2cap_send(connection->l2cap_signaling_cid, command, pos);
224 }
225 
226 static int avrcp_register_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
227     if (connection->notifications_to_deregister & (1 << event_id)) return 0;
228     if (connection->notifications_enabled & (1 << event_id)) return 0;
229     if (connection->notifications_to_register & (1 << event_id)) return 0;
230     connection->notifications_to_register |= (1 << event_id);
231     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
232     return 1;
233 }
234 
235 static void avrcp_prepare_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
236     connection->transaction_label++;
237     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
238     connection->command_type = AVRCP_CTYPE_NOTIFY;
239     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
240     connection->subunit_id = AVRCP_SUBUNIT_ID;
241     int pos = 0;
242     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
243     pos += 3;
244     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
245     connection->cmd_operands[pos++] = 0;                     // reserved(upper 6) | packet_type -> 0
246     big_endian_store_16(connection->cmd_operands, pos, 5);     // parameter length
247     pos += 2;
248     connection->cmd_operands[pos++] = event_id;
249     big_endian_store_32(connection->cmd_operands, pos, 1); // send notification on playback position every second, for other notifications it is ignored
250     pos += 4;
251     connection->cmd_operands_length = pos;
252     // AVRCP_SPEC_V14.pdf 166
253     // answer page 61
254 }
255 
256 
257 static void avrcp_parser_reset(avrcp_connection_t * connection){
258     connection->list_offset = 0;
259     connection->num_attributes = 0;
260     connection->num_parsed_attributes = 0;
261     connection->parser_attribute_header_pos = 0;
262     connection->num_received_fragments = 0;
263     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
264 }
265 
266 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){
267     uint8_t event[7];
268     int pos = 0;
269     event[pos++] = HCI_EVENT_AVRCP_META;
270     event[pos++] = sizeof(event) - 2;
271     event[pos++] = AVRCP_SUBEVENT_NOW_PLAYING_INFO_DONE;
272     little_endian_store_16(event, pos, avrcp_cid);
273     pos += 2;
274     event[pos++] = ctype;
275     event[pos++] = status;
276     // printf_hexdump(event, pos);
277     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
278 }
279 
280 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){
281     uint8_t event[HCI_EVENT_BUFFER_SIZE];
282     int pos = 0;
283     event[pos++] = HCI_EVENT_AVRCP_META;
284     // reserve one byte for subevent type and data len
285     int data_len_pos = pos;
286     pos++;
287     int subevent_type_pos = pos;
288     pos++;
289     little_endian_store_16(event, pos, avrcp_cid);
290     pos += 2;
291     event[pos++] = ctype;
292 
293     switch (attr_id){
294         case AVRCP_MEDIA_ATTR_TITLE:
295             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TITLE_INFO;
296             event[pos++] = value_len;
297             (void)memcpy(event + pos, value, value_len);
298             break;
299         case AVRCP_MEDIA_ATTR_ARTIST:
300             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ARTIST_INFO;
301             event[pos++] = value_len;
302             (void)memcpy(event + pos, value, value_len);
303             break;
304         case AVRCP_MEDIA_ATTR_ALBUM:
305             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ALBUM_INFO;
306             event[pos++] = value_len;
307             (void)memcpy(event + pos, value, value_len);
308             break;
309         case AVRCP_MEDIA_ATTR_GENRE:
310             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_GENRE_INFO;
311             event[pos++] = value_len;
312             (void)memcpy(event + pos, value, value_len);
313             break;
314         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
315             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_SONG_LENGTH_MS_INFO;
316             if (value){
317                 little_endian_store_32(event, pos, btstack_atoi((char *)value));
318             } else {
319                 little_endian_store_32(event, pos, 0);
320             }
321             pos += 4;
322             break;
323         case AVRCP_MEDIA_ATTR_TRACK:
324             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TRACK_INFO;
325             if (value){
326                 event[pos++] = btstack_atoi((char *)value);
327             } else {
328                 event[pos++] = 0;
329             }
330             break;
331         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
332             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TOTAL_TRACKS_INFO;
333             if (value){
334                 event[pos++] = btstack_atoi((char *)value);
335             } else {
336                 event[pos++] = 0;
337             }
338             break;
339         default:
340             break;
341     }
342     event[data_len_pos] = pos - 2;
343     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
344 }
345 
346 static void avrcp_parser_process_byte(uint8_t byte, avrcp_connection_t * connection, avrcp_command_type_t ctype){
347     uint16_t attribute_total_value_len;
348     uint32_t attribute_id;
349     // printf("avrcp_parser_process_byte: %02x, state %02x\n", byte, connection->parser_state);
350     switch(connection->parser_state){
351         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:
352             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
353             connection->list_offset++;
354 
355             if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN) return;
356 
357             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
358             connection->attribute_value_len = btstack_min(attribute_total_value_len, AVRCP_MAX_ATTRIBUTTE_SIZE);
359             if (connection->attribute_value_len > 0){
360                 // get ready for attribute value
361                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
362                 return;
363             }
364 
365             // emit empty attribute
366             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
367             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);
368 
369             // done, see below
370             break;
371 
372         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:
373             connection->attribute_value[connection->attribute_value_offset++] = byte;
374             connection->list_offset++;
375 
376             if (connection->attribute_value_offset < connection->attribute_value_len) return;
377 
378             // emit (potentially partial) attribute
379             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
380             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);
381 
382             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
383             if (connection->attribute_value_offset < attribute_total_value_len){
384                 // ignore rest of attribute
385                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
386                 return;
387             }
388 
389             // done, see below
390             break;
391 
392         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
393             connection->attribute_value_offset++;
394             connection->list_offset++;
395 
396             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
397             if (connection->attribute_value_offset < attribute_total_value_len) return;
398 
399             // done, see below
400             break;
401 
402         default:
403             return;
404     }
405 
406     // attribute fully read, check if more to come
407     if (connection->list_offset < connection->list_size){
408         // more to come, reset parser
409         connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
410         connection->parser_attribute_header_pos = 0;
411         connection->attribute_value_offset = 0;
412     } else {
413         // fully done
414         avrcp_parser_reset(connection);
415         avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 0);
416     }
417 }
418 
419 static void avrcp_source_parse_and_emit_element_attrs(uint8_t * packet, uint16_t num_bytes_to_read, avrcp_connection_t * connection, avrcp_command_type_t ctype){
420     int i;
421     for (i=0;i<num_bytes_to_read;i++){
422         avrcp_parser_process_byte(packet[i], connection, ctype);
423     }
424 }
425 
426 static uint8_t avrcp_controller_request_abort_continuation(avrcp_connection_t * connection){
427     connection->state = AVCTP_W2_SEND_COMMAND;
428     connection->transaction_label++;
429     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
430     connection->command_type = AVRCP_CTYPE_CONTROL;
431     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
432     connection->subunit_id = AVRCP_SUBUNIT_ID;
433     int pos = 0;
434     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
435     pos += 3;
436     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE; // PDU ID
437     connection->cmd_operands[pos++] = 0;
438     // Parameter Length
439     connection->cmd_operands_length = 8;
440     big_endian_store_16(connection->cmd_operands, pos, 1);
441     pos += 2;
442     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
443     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
444     return ERROR_CODE_SUCCESS;
445 }
446 
447 
448 static uint8_t avrcp_controller_request_continue_response(avrcp_connection_t * connection){
449     connection->state = AVCTP_W2_SEND_COMMAND;
450     connection->transaction_label++;
451     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
452     connection->command_type = AVRCP_CTYPE_CONTROL;
453     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
454     connection->subunit_id = AVRCP_SUBUNIT_ID;
455     int pos = 0;
456     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
457     pos += 3;
458     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE; // PDU ID
459     connection->cmd_operands[pos++] = 0;
460     // Parameter Length
461     connection->cmd_operands_length = 8;
462     big_endian_store_16(connection->cmd_operands, pos, 1);
463     pos += 2;
464     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
465     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
466     return ERROR_CODE_SUCCESS;
467 }
468 
469 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
470     uint8_t operands[20];
471     uint8_t opcode;
472     int     pos = 3;
473 
474     if (size < 6u) return;
475 
476     avrcp_command_type_t ctype = (avrcp_command_type_t) packet[pos++];
477     uint8_t byte_value = packet[pos++];
478     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (byte_value >> 3);
479     avrcp_subunit_type_t subunit_id = (avrcp_subunit_type_t)   (byte_value & 0x07);
480     opcode = packet[pos++];
481 
482     uint8_t pdu_id;
483     uint16_t param_length;
484     switch (avrcp_cmd_opcode(packet,size)){
485         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
486             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
487             connection->state = AVCTP_CONNECTION_OPENED;
488             // operands:
489             (void)memcpy(operands, packet + pos, 5);
490             uint8_t unit_type = operands[1] >> 3;
491             uint8_t max_subunit_ID = operands[1] & 0x07;
492             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);
493             break;
494         }
495         case AVRCP_CMD_OPCODE_UNIT_INFO:{
496             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
497             connection->state = AVCTP_CONNECTION_OPENED;
498             // operands:
499             (void)memcpy(operands, packet + pos, 5);
500             uint8_t unit_type = operands[1] >> 3;
501             uint8_t unit = operands[1] & 0x07;
502             uint32_t company_id = (operands[2] << 16) | (operands[3] << 8) | operands[4];
503             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,
504                 ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id);
505             break;
506         }
507         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
508             if ((size - pos) < 7) {
509                 log_error("avrcp: wrong packet size");
510                 return;
511             };
512             // operands:
513             (void)memcpy(operands, packet + pos, 7);
514             pos += 7;
515             pdu_id = operands[3];
516 
517             if ((connection->state != AVCTP_W2_RECEIVE_RESPONSE) && (pdu_id != AVRCP_PDU_ID_REGISTER_NOTIFICATION)){
518                 log_info("AVRCP_CMD_OPCODE_VENDOR_DEPENDENT state %d", connection->state);
519                 return;
520             }
521             connection->state = AVCTP_CONNECTION_OPENED;
522 
523             param_length = big_endian_read_16(operands, 5);
524 
525             log_info("        VENDOR DEPENDENT response: pdu id 0x%02x, param_length %d, status %s", pdu_id, param_length, avrcp_ctype2str(ctype));
526             switch (pdu_id){
527                 case AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE:{
528                     uint8_t num_attributes = packet[pos++];
529                     int i;
530                     avrcp_repeat_mode_t  repeat_mode =  AVRCP_REPEAT_MODE_INVALID;
531                     avrcp_shuffle_mode_t shuffle_mode = AVRCP_SHUFFLE_MODE_INVALID;
532                     for (i = 0; i < num_attributes; i++){
533                         uint8_t attribute_id    = packet[pos++];
534                         uint8_t value = packet[pos++];
535                         switch (attribute_id){
536                             case 0x02:
537                                 repeat_mode = (avrcp_repeat_mode_t) value;
538                                 break;
539                             case 0x03:
540                                 shuffle_mode = (avrcp_shuffle_mode_t) value;
541                                 break;
542                             default:
543                                 break;
544                         }
545                     }
546                     avrcp_emit_repeat_and_shuffle_mode(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, repeat_mode, shuffle_mode);
547                     break;
548                 }
549                 case AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE:{
550                     uint8_t event[6];
551                     int offset = 0;
552                     event[offset++] = HCI_EVENT_AVRCP_META;
553                     event[offset++] = sizeof(event) - 2;
554                     event[offset++] = AVRCP_SUBEVENT_PLAYER_APPLICATION_VALUE_RESPONSE;
555                     little_endian_store_16(event, offset, connection->avrcp_cid);
556                     offset += 2;
557                     event[offset++] = ctype;
558                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
559                     break;
560                 }
561                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME:{
562                     uint8_t event[7];
563                     int offset = 0;
564                     event[offset++] = HCI_EVENT_AVRCP_META;
565                     event[offset++] = sizeof(event) - 2;
566                     event[offset++] = AVRCP_SUBEVENT_SET_ABSOLUTE_VOLUME_RESPONSE;
567                     little_endian_store_16(event, offset, connection->avrcp_cid);
568                     offset += 2;
569                     event[offset++] = ctype;
570                     event[offset++] = packet[pos++];
571                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
572                     break;
573                 }
574                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
575                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos++];
576                     uint8_t capability_count = packet[pos++];
577                     int i;
578 
579                     switch (capability_id){
580                         int offset = 0;
581                         uint8_t event[10];
582 
583                         case AVRCP_CAPABILITY_ID_COMPANY:
584                             for (i = 0; i < capability_count; i++){
585                                 uint32_t company_id = big_endian_read_24(packet, pos);
586                                 pos += 3;
587                                 log_info("  0x%06" PRIx32 ", ", company_id);
588 
589                                 offset = 0;
590                                 event[offset++] = HCI_EVENT_AVRCP_META;
591                                 event[offset++] = sizeof(event) - 2;
592                                 event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID;
593                                 little_endian_store_16(event, offset, connection->avrcp_cid);
594                                 offset += 2;
595                                 event[offset++] = ctype;
596                                 event[offset++] = 0;
597                                 little_endian_store_24(event, offset, company_id);
598                                 offset += 3;
599                                 (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
600                                 break;
601                             }
602 
603                             offset = 0;
604                             event[offset++] = HCI_EVENT_AVRCP_META;
605                             event[offset++] = sizeof(event) - 2;
606                             event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_COMPANY_ID_DONE;
607                             little_endian_store_16(event, offset, connection->avrcp_cid);
608                             offset += 2;
609                             event[offset++] = ctype;
610                             event[offset++] = 0;
611                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
612                             break;
613 
614                         case AVRCP_CAPABILITY_ID_EVENT:
615                             for (i = 0; i < capability_count; i++){
616                                 uint8_t event_id = packet[pos++];
617                                 log_info("  0x%02x %s", event_id, avrcp_event2str(event_id));
618 
619                                 offset = 0;
620                                 event[offset++] = HCI_EVENT_AVRCP_META;
621                                 event[offset++] = sizeof(event) - 2;
622                                 event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID;
623                                 little_endian_store_16(event, offset, connection->avrcp_cid);
624                                 offset += 2;
625                                 event[offset++] = ctype;
626                                 event[offset++] = 0;
627                                 event[offset++] = event_id;
628                                 (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, offset);
629                             }
630 
631                             offset = 0;
632                             event[offset++] = HCI_EVENT_AVRCP_META;
633                             event[offset++] = sizeof(event) - 2;
634                             event[offset++] = AVRCP_SUBEVENT_GET_CAPABILITY_EVENT_ID_DONE;
635                             little_endian_store_16(event, offset, connection->avrcp_cid);
636                             offset += 2;
637                             event[offset++] = ctype;
638                             event[offset++] = 0;
639                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
640                             break;
641                     }
642                     break;
643                 }
644                 case AVRCP_PDU_ID_GET_PLAY_STATUS:{
645                     uint32_t song_length = big_endian_read_32(packet, pos);
646                     pos += 4;
647                     uint32_t song_position = big_endian_read_32(packet, pos);
648                     pos += 4;
649                     uint8_t play_status = packet[pos];
650 
651                     uint8_t event[15];
652                     int offset = 0;
653                     event[offset++] = HCI_EVENT_AVRCP_META;
654                     event[offset++] = sizeof(event) - 2;
655                     event[offset++] = AVRCP_SUBEVENT_PLAY_STATUS;
656                     little_endian_store_16(event, offset, connection->avrcp_cid);
657                     offset += 2;
658                     event[offset++] = ctype;
659                     little_endian_store_32(event, offset, song_length);
660                     offset += 4;
661                     little_endian_store_32(event, offset, song_position);
662                     offset += 4;
663                     event[offset++] = play_status;
664                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
665                     break;
666                 }
667                 case AVRCP_PDU_ID_REGISTER_NOTIFICATION:{
668                     avrcp_notification_event_id_t  event_id = (avrcp_notification_event_id_t) packet[pos++];
669                     uint16_t event_mask = (1 << event_id);
670                     uint16_t reset_event_mask = ~event_mask;
671                     switch (ctype){
672                         case AVRCP_CTYPE_RESPONSE_INTERIM:
673                             // register as enabled
674                             connection->notifications_enabled |= event_mask;
675                             break;
676                         case AVRCP_CTYPE_RESPONSE_CHANGED_STABLE:
677                             // received change, event is considered deregistered
678                             // we are re-enabling it automatically, if it is not
679                             // explicitly disabled
680                             connection->notifications_enabled &= reset_event_mask;
681                             if (! (connection->notifications_to_deregister & event_mask)){
682                                 avrcp_register_notification(connection, event_id);
683                             } else {
684                                 connection->notifications_to_deregister &= reset_event_mask;
685                             }
686                             break;
687                         default:
688                             connection->notifications_to_register &= reset_event_mask;
689                             connection->notifications_enabled &= reset_event_mask;
690                             connection->notifications_to_deregister &= reset_event_mask;
691                             break;
692                     }
693 
694                     switch (event_id){
695                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_POS_CHANGED:{
696                             uint32_t song_position = big_endian_read_32(packet, pos);
697                             uint8_t event[10];
698                             int offset = 0;
699                             event[offset++] = HCI_EVENT_AVRCP_META;
700                             event[offset++] = sizeof(event) - 2;
701                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_POS_CHANGED;
702                             little_endian_store_16(event, offset, connection->avrcp_cid);
703                             offset += 2;
704                             event[offset++] = ctype;
705                             little_endian_store_32(event, offset, song_position);
706                             offset += 4;
707                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
708                             break;
709                         }
710                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:{
711                             uint8_t event[7];
712                             int offset = 0;
713                             event[offset++] = HCI_EVENT_AVRCP_META;
714                             event[offset++] = sizeof(event) - 2;
715                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_STATUS_CHANGED;
716                             little_endian_store_16(event, offset, connection->avrcp_cid);
717                             offset += 2;
718                             event[offset++] = ctype;
719                             event[offset++] = packet[pos];
720                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
721                             break;
722                         }
723                         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:{
724                             uint8_t event[6];
725                             int offset = 0;
726                             event[offset++] = HCI_EVENT_AVRCP_META;
727                             event[offset++] = sizeof(event) - 2;
728                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_TRACK_CHANGED;
729                             little_endian_store_16(event, offset, connection->avrcp_cid);
730                             offset += 2;
731                             event[offset++] = ctype;
732                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
733                             break;
734                         }
735                         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:{
736                             uint8_t event[6];
737                             int offset = 0;
738                             event[offset++] = HCI_EVENT_AVRCP_META;
739                             event[offset++] = sizeof(event) - 2;
740                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_NOW_PLAYING_CONTENT_CHANGED;
741                             little_endian_store_16(event, offset, connection->avrcp_cid);
742                             offset += 2;
743                             event[offset++] = ctype;
744                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
745                             break;
746                         }
747                         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:{
748                             uint8_t event[6];
749                             int offset = 0;
750                             event[offset++] = HCI_EVENT_AVRCP_META;
751                             event[offset++] = sizeof(event) - 2;
752                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_AVAILABLE_PLAYERS_CHANGED;
753                             little_endian_store_16(event, offset, connection->avrcp_cid);
754                             offset += 2;
755                             event[offset++] = ctype;
756                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
757                             break;
758                         }
759                         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:{
760                             uint8_t event[7];
761                             int offset = 0;
762                             event[offset++] = HCI_EVENT_AVRCP_META;
763                             event[offset++] = sizeof(event) - 2;
764                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
765                             little_endian_store_16(event, offset, connection->avrcp_cid);
766                             offset += 2;
767                             event[offset++] = ctype;
768                             event[offset++] = packet[pos++] & 0x7F;
769                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
770                             break;
771                         }
772                         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:{
773                             uint8_t event[8];
774                             uint16_t uuid = big_endian_read_16(packet, pos);
775                             int offset = 0;
776                             event[offset++] = HCI_EVENT_AVRCP_META;
777                             event[offset++] = sizeof(event) - 2;
778                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_UIDS_CHANGED;
779                             little_endian_store_16(event, offset, connection->avrcp_cid);
780                             offset += 2;
781                             event[offset++] = ctype;
782                             little_endian_store_16(event, offset, uuid);
783                             offset += 2;
784                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
785                             break;
786                         }
787 
788                         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_END:{
789                             uint8_t event[6];
790                             int offset = 0;
791                             event[offset++] = HCI_EVENT_AVRCP_META;
792                             event[offset++] = sizeof(event) - 2;
793                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_END;
794                             little_endian_store_16(event, offset, connection->avrcp_cid);
795                             offset += 2;
796                             event[offset++] = ctype;
797                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
798                             break;
799                         }
800                         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_START:{
801                             uint8_t event[6];
802                             int offset = 0;
803                             event[offset++] = HCI_EVENT_AVRCP_META;
804                             event[offset++] = sizeof(event) - 2;
805                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_TRACK_REACHED_START;
806                             little_endian_store_16(event, offset, connection->avrcp_cid);
807                             offset += 2;
808                             event[offset++] = ctype;
809                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
810                             break;
811                         }
812                         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:{
813                             uint8_t event[7];
814                             int offset = 0;
815                             event[offset++] = HCI_EVENT_AVRCP_META;
816                             event[offset++] = sizeof(event) - 2;
817                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_BATT_STATUS_CHANGED;
818                             little_endian_store_16(event, offset, connection->avrcp_cid);
819                             offset += 2;
820                             event[offset++] = ctype;
821                             event[offset++] = packet[pos++];
822                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
823                             break;
824                         }
825 
826                         case AVRCP_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED:{
827                             uint8_t event[7];
828                             int offset = 0;
829                             event[offset++] = HCI_EVENT_AVRCP_META;
830                             event[offset++] = sizeof(event) - 2;
831                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED;
832                             little_endian_store_16(event, offset, connection->avrcp_cid);
833                             offset += 2;
834                             event[offset++] = ctype;
835                             event[offset++] = packet[pos];
836                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
837                             break;
838                         }
839 
840                         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
841                         default:
842                             log_info("avrcp: not implemented");
843                             break;
844                     }
845                     if (connection->notifications_to_register != 0){
846                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
847                     }
848                     break;
849                 }
850 
851                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
852                     avrcp_packet_type_t packet_type = (avrcp_packet_type_t) (operands[4] & 0x03);
853                     switch (packet_type){
854                         case AVRCP_START_PACKET:
855                         case AVRCP_SINGLE_PACKET:
856                             avrcp_parser_reset(connection);
857                             connection->list_size = param_length;
858                             connection->num_attributes = packet[pos++];
859 
860                             avrcp_source_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
861 
862                             if (packet_type == AVRCP_START_PACKET){
863                                 avrcp_controller_request_continue_response(connection);
864                             }
865                             break;
866                         case AVRCP_CONTINUE_PACKET:
867                         case AVRCP_END_PACKET:
868                             connection->num_received_fragments++;
869                             if (connection->num_received_fragments < connection->max_num_fragments){
870                                 avrcp_source_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
871                                 if (packet_type == AVRCP_CONTINUE_PACKET){
872                                     avrcp_controller_request_continue_response(connection);
873                                 }
874                             } else {
875                                 avrcp_controller_request_abort_continuation(connection);
876                                 avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 1);
877                                 avrcp_parser_reset(connection);
878                             }
879                             break;
880                     }
881                 }
882                 default:
883                     break;
884             }
885             break;
886         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
887             // 0x80 | connection->cmd_operands[0]
888             uint8_t operation_id = packet[pos++];
889             switch (connection->state){
890                 case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
891                     if (connection->continuous_fast_forward_cmd){
892                         connection->state = AVCTP_W4_STOP;
893                     } else {
894                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
895                     }
896                     break;
897                 case AVCTP_W2_RECEIVE_RESPONSE:
898                     connection->state = AVCTP_CONNECTION_OPENED;
899                     break;
900                 default:
901                     break;
902             }
903             if (connection->state == AVCTP_W4_STOP){
904                 avrcp_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_START, connection->avrcp_cid, ctype, operation_id);
905             }
906             if (connection->state == AVCTP_CONNECTION_OPENED) {
907                 // RELEASE response
908                 operation_id = operation_id & 0x7F;
909                 avrcp_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_COMPLETE, connection->avrcp_cid, ctype, operation_id);
910             }
911             if (connection->state == AVCTP_W2_SEND_RELEASE_COMMAND){
912                 // PRESS response
913                 request_pass_through_release_control_cmd(connection);
914             }
915             break;
916         }
917         default:
918             break;
919     }
920 
921     // trigger pending notification reqistrations
922     if ((connection->state == AVCTP_CONNECTION_OPENED) && connection->notifications_to_register){
923         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
924     }
925 }
926 
927 static void avrcp_controller_handle_can_send_now(avrcp_connection_t * connection){
928     int i;
929     switch (connection->state){
930         case AVCTP_W2_SEND_PRESS_COMMAND:
931             connection->state = AVCTP_W2_RECEIVE_PRESS_RESPONSE;
932             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
933             break;
934         case AVCTP_W2_SEND_COMMAND:
935         case AVCTP_W2_SEND_RELEASE_COMMAND:
936             connection->state = AVCTP_W2_RECEIVE_RESPONSE;
937             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
938             break;
939         case AVCTP_CONNECTION_OPENED:
940             if (connection->notifications_to_register != 0){
941                 for (i = 1; i <= AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED; i++){
942                     if (connection->notifications_to_register & (1<<i)){
943                         connection->notifications_to_register &= ~ (1 << i);
944                         avrcp_prepare_notification(connection, (avrcp_notification_event_id_t) i);
945                         connection->state = AVCTP_W2_RECEIVE_RESPONSE;
946                         avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
947                         return;
948                     }
949                 }
950             }
951             return;
952         case AVCTP_W2_SEND_FRAGMENTED_COMMAND:
953             if (connection->cmd_operands_fragmented_pos == 0){
954                  avrcp_send_cmd(connection, AVRCP_START_PACKET);
955                  avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
956             } else {
957                 if ((connection->cmd_operands_fragmented_len - connection->cmd_operands_fragmented_pos) > avrcp_get_max_payload_size_for_packet_type(AVRCP_CONTINUE_PACKET)){
958                      avrcp_send_cmd(connection, AVRCP_CONTINUE_PACKET);
959                      avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
960                  } else {
961                     connection->state = AVCTP_W2_RECEIVE_RESPONSE;
962                     avrcp_send_cmd(connection, AVRCP_END_PACKET);
963                  }
964             }
965         default:
966             return;
967     }
968 }
969 
970 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
971     avrcp_connection_t * connection;
972 
973     switch (packet_type) {
974         case L2CAP_DATA_PACKET:
975             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
976             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
977             break;
978 
979         case HCI_EVENT_PACKET:
980             switch (hci_event_packet_get_type(packet)){
981                 case L2CAP_EVENT_CAN_SEND_NOW:
982                     connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
983                     avrcp_controller_handle_can_send_now(connection);
984                     break;
985             default:
986                 break;
987         }
988         default:
989             break;
990     }
991 }
992 
993 void avrcp_controller_init(void){
994     avrcp_controller_context.role = AVRCP_CONTROLLER;
995     avrcp_controller_context.packet_handler = avrcp_controller_packet_handler;
996     avrcp_register_controller_packet_handler(&avrcp_controller_packet_handler);
997 }
998 
999 void avrcp_controller_register_packet_handler(btstack_packet_handler_t callback){
1000     btstack_assert(callback != NULL);
1001     avrcp_controller_context.avrcp_callback = callback;
1002 }
1003 
1004 uint8_t avrcp_controller_unit_info(uint16_t avrcp_cid){
1005     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1006     if (!connection){
1007         log_error("avrcp_unit_info: could not find a connection.");
1008         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1009     }
1010     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1011     connection->state = AVCTP_W2_SEND_COMMAND;
1012 
1013     connection->transaction_label++;
1014     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
1015     connection->command_type = AVRCP_CTYPE_STATUS;
1016     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
1017     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
1018     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
1019     connection->cmd_operands_length = 5;
1020     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1021     return ERROR_CODE_SUCCESS;
1022 }
1023 
1024 uint8_t avrcp_controller_subunit_info(uint16_t avrcp_cid){
1025     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1026     if (!connection){
1027         log_error("avrcp_unit_info: could not find a connection.");
1028         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1029     }
1030     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1031     connection->state = AVCTP_W2_SEND_COMMAND;
1032 
1033     connection->transaction_label++;
1034     connection->command_opcode = AVRCP_CMD_OPCODE_SUBUNIT_INFO;
1035     connection->command_type = AVRCP_CTYPE_STATUS;
1036     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
1037     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
1038     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
1039     connection->cmd_operands[0] = 7; // page: 0, extention_code: 7
1040     connection->cmd_operands_length = 5;
1041     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1042     return ERROR_CODE_SUCCESS;
1043 }
1044 
1045 static uint8_t avrcp_controller_get_capabilities(uint16_t avrcp_cid, uint8_t capability_id){
1046     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1047     if (!connection){
1048         log_error("avrcp_get_capabilities: could not find a connection.");
1049         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1050     }
1051     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1052     connection->state = AVCTP_W2_SEND_COMMAND;
1053 
1054     connection->transaction_label++;
1055     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1056     connection->command_type = AVRCP_CTYPE_STATUS;
1057     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1058     connection->subunit_id = AVRCP_SUBUNIT_ID;
1059     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1060     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CAPABILITIES; // PDU ID
1061     connection->cmd_operands[4] = 0;
1062     big_endian_store_16(connection->cmd_operands, 5, 1); // parameter length
1063     connection->cmd_operands[7] = capability_id;                  // capability ID
1064     connection->cmd_operands_length = 8;
1065     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1066     return ERROR_CODE_SUCCESS;
1067 }
1068 
1069 uint8_t avrcp_controller_get_supported_company_ids(uint16_t avrcp_cid){
1070     return avrcp_controller_get_capabilities(avrcp_cid, AVRCP_CAPABILITY_ID_COMPANY);
1071 }
1072 
1073 uint8_t avrcp_controller_get_supported_events(uint16_t avrcp_cid){
1074     return avrcp_controller_get_capabilities(avrcp_cid, AVRCP_CAPABILITY_ID_EVENT);
1075 }
1076 
1077 
1078 uint8_t avrcp_controller_play(uint16_t avrcp_cid){
1079     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1080 }
1081 
1082 uint8_t avrcp_controller_stop(uint16_t avrcp_cid){
1083     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1084 }
1085 
1086 uint8_t avrcp_controller_pause(uint16_t avrcp_cid){
1087     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1088 }
1089 
1090 uint8_t avrcp_controller_forward(uint16_t avrcp_cid){
1091     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1092 }
1093 
1094 uint8_t avrcp_controller_backward(uint16_t avrcp_cid){
1095     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1096 }
1097 
1098 uint8_t avrcp_controller_volume_up(uint16_t avrcp_cid){
1099     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1100 }
1101 
1102 uint8_t avrcp_controller_volume_down(uint16_t avrcp_cid){
1103     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1104 }
1105 
1106 uint8_t avrcp_controller_mute(uint16_t avrcp_cid){
1107     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1108 }
1109 
1110 uint8_t avrcp_controller_skip(uint16_t avrcp_cid){
1111     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_SKIP, 0);
1112 }
1113 
1114 uint8_t avrcp_controller_fast_forward(uint16_t avrcp_cid){
1115     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1116 }
1117 
1118 uint8_t avrcp_controller_rewind(uint16_t avrcp_cid){
1119     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1120 }
1121 
1122 
1123 /* start cmds */
1124 
1125 uint8_t avrcp_controller_release_press_and_hold_cmd(uint16_t avrcp_cid){
1126     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1127     if (!connection){
1128         log_error("avrcp_stop_play: could not find a connection.");
1129         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1130     }
1131     if (connection->state != AVCTP_W4_STOP) return ERROR_CODE_COMMAND_DISALLOWED;
1132     return request_pass_through_release_control_cmd(connection);
1133 }
1134 
1135 uint8_t avrcp_controller_press_and_hold_play(uint16_t avrcp_cid){
1136     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1137 }
1138 uint8_t avrcp_controller_press_and_hold_stop(uint16_t avrcp_cid){
1139     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1140 }
1141 uint8_t avrcp_controller_press_and_hold_pause(uint16_t avrcp_cid){
1142     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1143 }
1144 uint8_t avrcp_controller_press_and_hold_forward(uint16_t avrcp_cid){
1145     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1146 }
1147 uint8_t avrcp_controller_press_and_hold_backward(uint16_t avrcp_cid){
1148     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1149 }
1150 uint8_t avrcp_controller_press_and_hold_fast_forward(uint16_t avrcp_cid){
1151     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1152 }
1153 uint8_t avrcp_controller_press_and_hold_rewind(uint16_t avrcp_cid){
1154     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1155 }
1156 uint8_t avrcp_controller_press_and_hold_volume_up(uint16_t avrcp_cid){
1157     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1158 }
1159 uint8_t avrcp_controller_press_and_hold_volume_down(uint16_t avrcp_cid){
1160     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1161 }
1162 uint8_t avrcp_controller_press_and_hold_mute(uint16_t avrcp_cid){
1163     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1164 }
1165 
1166 
1167 /* stop continuous cmds */
1168 
1169 uint8_t avrcp_controller_get_play_status(uint16_t avrcp_cid){
1170     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1171     if (!connection){
1172         log_error("avrcp_get_play_status: could not find a connection.");
1173         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1174     }
1175     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1176     connection->state = AVCTP_W2_SEND_COMMAND;
1177     connection->transaction_label++;
1178     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1179     connection->command_type = AVRCP_CTYPE_STATUS;
1180     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1181     connection->subunit_id = AVRCP_SUBUNIT_ID;
1182     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1183     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_PLAY_STATUS;
1184     connection->cmd_operands[4] = 0;                     // reserved(upper 6) | packet_type -> 0
1185     big_endian_store_16(connection->cmd_operands, 5, 0); // parameter length
1186     connection->cmd_operands_length = 7;
1187     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1188     return ERROR_CODE_SUCCESS;
1189 }
1190 
1191 uint8_t avrcp_controller_enable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1192     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1193     if (!connection){
1194         log_error("avrcp_get_play_status: could not find a connection.");
1195         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1196     }
1197     avrcp_register_notification(connection, event_id);
1198     return ERROR_CODE_SUCCESS;
1199 }
1200 
1201 uint8_t avrcp_controller_disable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1202     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1203     if (!connection){
1204         log_error("avrcp_get_play_status: could not find a connection.");
1205         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1206     }
1207     connection->notifications_to_deregister |= (1 << event_id);
1208     return ERROR_CODE_SUCCESS;
1209 }
1210 
1211 uint8_t avrcp_controller_set_addressed_player(uint16_t avrcp_cid, uint16_t addressed_player_id){
1212     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1213     if (!connection){
1214         log_error("avrcp_get_capabilities: could not find a connection.");
1215         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1216     }
1217     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1218     connection->state = AVCTP_W2_SEND_COMMAND;
1219 
1220     connection->transaction_label++;
1221     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1222     connection->command_type = AVRCP_CTYPE_CONTROL;
1223     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1224     connection->subunit_id = AVRCP_SUBUNIT_ID;
1225     int pos = 0;
1226     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1227     pos += 3;
1228     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ADDRESSED_PLAYER; // PDU ID
1229     connection->cmd_operands[pos++] = 0;
1230 
1231     // Parameter Length
1232     big_endian_store_16(connection->cmd_operands, pos, 2);
1233     pos += 2;
1234 
1235     big_endian_store_16(connection->cmd_operands, pos, addressed_player_id);
1236     pos += 2;
1237 
1238     connection->cmd_operands_length = pos;
1239     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1240     return ERROR_CODE_SUCCESS;
1241 }
1242 
1243 uint8_t avrcp_controller_get_now_playing_info(uint16_t avrcp_cid){
1244     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1245     if (!connection){
1246         log_error("avrcp_get_capabilities: could not find a connection.");
1247         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1248     }
1249     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1250     connection->state = AVCTP_W2_SEND_COMMAND;
1251 
1252     connection->transaction_label++;
1253     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1254     connection->command_type = AVRCP_CTYPE_STATUS;
1255     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1256     connection->subunit_id = AVRCP_SUBUNIT_ID;
1257     int pos = 0;
1258     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1259     pos += 3;
1260     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES; // PDU ID
1261     connection->cmd_operands[pos++] = 0;
1262 
1263     // Parameter Length
1264     big_endian_store_16(connection->cmd_operands, pos, 9);
1265     pos += 2;
1266 
1267     // write 8 bytes value
1268     memset(connection->cmd_operands + pos, 0, 8); // identifier: PLAYING
1269     pos += 8;
1270 
1271     connection->cmd_operands[pos++] = 0; // attribute count, if 0 get all attributes
1272     // every attribute is 4 bytes long
1273 
1274     connection->cmd_operands_length = pos;
1275     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1276     return ERROR_CODE_SUCCESS;
1277 }
1278 
1279 uint8_t avrcp_controller_set_absolute_volume(uint16_t avrcp_cid, uint8_t volume){
1280      avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1281     if (!connection){
1282         log_error("avrcp_get_capabilities: could not find a connection.");
1283         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1284     }
1285     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1286     connection->state = AVCTP_W2_SEND_COMMAND;
1287 
1288     connection->transaction_label++;
1289     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1290     connection->command_type = AVRCP_CTYPE_CONTROL;
1291     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1292     connection->subunit_id = AVRCP_SUBUNIT_ID;
1293     int pos = 0;
1294     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1295     pos += 3;
1296     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME; // PDU ID
1297     connection->cmd_operands[pos++] = 0;
1298 
1299     // Parameter Length
1300     big_endian_store_16(connection->cmd_operands, pos, 1);
1301     pos += 2;
1302     connection->cmd_operands[pos++] = volume;
1303 
1304     connection->cmd_operands_length = pos;
1305     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1306     return ERROR_CODE_SUCCESS;
1307 }
1308 
1309 uint8_t avrcp_controller_query_shuffle_and_repeat_modes(uint16_t avrcp_cid){
1310     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1311     if (!connection){
1312         log_error("avrcp_get_capabilities: could not find a connection.");
1313         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1314     }
1315     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1316     connection->state = AVCTP_W2_SEND_COMMAND;
1317 
1318     connection->transaction_label++;
1319     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1320     connection->command_type = AVRCP_CTYPE_STATUS;
1321     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1322     connection->subunit_id = AVRCP_SUBUNIT_ID;
1323     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1324     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CURRENT_PLAYER_APPLICATION_SETTING_VALUE; // PDU ID
1325     connection->cmd_operands[4] = 0;
1326     big_endian_store_16(connection->cmd_operands, 5, 5); // parameter length
1327     connection->cmd_operands[7] = 4;                     // NumPlayerApplicationSettingAttributeID
1328     // PlayerApplicationSettingAttributeID1 AVRCP Spec, Appendix F, 133
1329     connection->cmd_operands[8]  = 0x01;    // equalizer  (1-OFF, 2-ON)
1330     connection->cmd_operands[9]  = 0x02;    // repeat     (1-off, 2-single track, 3-all tracks, 4-group repeat)
1331     connection->cmd_operands[10] = 0x03;    // shuffle    (1-off, 2-all tracks, 3-group shuffle)
1332     connection->cmd_operands[11] = 0x04;    // scan       (1-off, 2-all tracks, 3-group scan)
1333     connection->cmd_operands_length = 12;
1334     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1335     return ERROR_CODE_SUCCESS;
1336 }
1337 
1338 static uint8_t avrcp_controller_set_current_player_application_setting_value(uint16_t avrcp_cid, uint8_t attr_id, uint8_t attr_value){
1339     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1340     if (!connection){
1341         log_error("avrcp_get_capabilities: could not find a connection.");
1342         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1343     }
1344     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1345     connection->state = AVCTP_W2_SEND_COMMAND;
1346 
1347     connection->transaction_label++;
1348     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1349     connection->command_type = AVRCP_CTYPE_CONTROL;
1350     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1351     connection->subunit_id = AVRCP_SUBUNIT_ID;
1352     int pos = 0;
1353     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1354     pos += 3;
1355     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_PLAYER_APPLICATION_SETTING_VALUE; // PDU ID
1356     connection->cmd_operands[pos++] = 0;
1357     // Parameter Length
1358     big_endian_store_16(connection->cmd_operands, pos, 3);
1359     pos += 2;
1360     connection->cmd_operands[pos++] = 2;
1361     connection->cmd_operands_length = pos;
1362     connection->cmd_operands[pos++]  = attr_id;
1363     connection->cmd_operands[pos++]  = attr_value;
1364     connection->cmd_operands_length = pos;
1365     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1366     return ERROR_CODE_SUCCESS;
1367 }
1368 
1369 uint8_t avrcp_controller_set_shuffle_mode(uint16_t avrcp_cid, avrcp_shuffle_mode_t mode){
1370     if ((mode < AVRCP_SHUFFLE_MODE_OFF) || (mode > AVRCP_SHUFFLE_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1371     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x03, mode);
1372 }
1373 
1374 uint8_t avrcp_controller_set_repeat_mode(uint16_t avrcp_cid, avrcp_repeat_mode_t mode){
1375     if ((mode < AVRCP_REPEAT_MODE_OFF) || (mode > AVRCP_REPEAT_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1376     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x02, mode);
1377 }
1378 
1379 uint8_t avrcp_controller_play_item_for_scope(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1380     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1381     if (!connection){
1382         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1383         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1384     }
1385     if (connection->state != AVCTP_CONNECTION_OPENED){
1386         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1387         return ERROR_CODE_COMMAND_DISALLOWED;
1388     }
1389     connection->state = AVCTP_W2_SEND_COMMAND;
1390 
1391     connection->transaction_label++;
1392     connection->command_type = AVRCP_CTYPE_CONTROL;
1393     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1394     connection->subunit_id = AVRCP_SUBUNIT_ID;
1395     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1396     int pos = 0;
1397     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1398     pos += 3;
1399     connection->cmd_operands[pos++] = AVRCP_PDU_ID_PLAY_ITEM; // PDU ID
1400     // reserved
1401     connection->cmd_operands[pos++] = 0;
1402     // Parameter Length
1403     big_endian_store_16(connection->cmd_operands, pos, 11);
1404     pos += 2;
1405     connection->cmd_operands[pos++]  = scope;
1406     memset(&connection->cmd_operands[pos], 0, 8);
1407     if (uid){
1408         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1409     }
1410     pos += 8;
1411     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1412     pos += 2;
1413     connection->cmd_operands_length = pos;
1414 
1415     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1416     return ERROR_CODE_SUCCESS;
1417 }
1418 
1419 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){
1420     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1421     if (!connection){
1422         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1423         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1424     }
1425     if (connection->state != AVCTP_CONNECTION_OPENED){
1426         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1427         return ERROR_CODE_COMMAND_DISALLOWED;
1428     }
1429     connection->state = AVCTP_W2_SEND_COMMAND;
1430 
1431     connection->transaction_label++;
1432     connection->command_type = AVRCP_CTYPE_CONTROL;
1433     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1434     connection->subunit_id = AVRCP_SUBUNIT_ID;
1435     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1436     int pos = 0;
1437     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1438     pos += 3;
1439     connection->cmd_operands[pos++] = AVRCP_PDU_ID_ADD_TO_NOW_PLAYING; // PDU ID
1440     // reserved
1441     connection->cmd_operands[pos++] = 0;
1442     // Parameter Length
1443     big_endian_store_16(connection->cmd_operands, pos, 11);
1444     pos += 2;
1445     connection->cmd_operands[pos++]  = scope;
1446     memset(&connection->cmd_operands[pos], 0, 8);
1447     if (uid){
1448         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1449     }
1450     pos += 8;
1451     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1452     pos += 2;
1453     connection->cmd_operands_length = pos;
1454 
1455     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1456     return ERROR_CODE_SUCCESS;
1457 }
1458 
1459 uint8_t avrcp_controller_set_max_num_fragments(uint16_t avrcp_cid, uint8_t max_num_fragments){
1460     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1461     if (!connection){
1462         log_error("avrcp_controller_play_item: could not find a connection.");
1463         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1464     }
1465     connection->max_num_fragments = max_num_fragments;
1466     return ERROR_CODE_SUCCESS;
1467 }
1468 
1469 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){
1470     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1471     if (!connection){
1472         log_error("avrcp_controller_play_item: could not find a connection.");
1473         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1474     }
1475 
1476     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1477     connection->state = AVCTP_W2_SEND_FRAGMENTED_COMMAND;
1478 
1479     connection->transaction_label++;
1480     connection->command_opcode = command_opcode;
1481     connection->command_type = command_type;
1482     connection->subunit_type = subunit_type;
1483     connection->subunit_id = subunit_id;
1484     connection->cmd_operands_fragmented_buffer = command_buffer;
1485     connection->cmd_operands_fragmented_pos = 0;
1486     connection->cmd_operands_fragmented_len = command_len;
1487 
1488     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1489     return ERROR_CODE_SUCCESS;
1490 }
1491