xref: /btstack/src/classic/avrcp_controller.c (revision e3d57ee2cf777da36858b158bf0f9b68f9e5811c)
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 <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <inttypes.h>
45 
46 #include "btstack.h"
47 #include "classic/avrcp.h"
48 #include "classic/avrcp_controller.h"
49 
50 // made public in avrcp_controller.h
51 avrcp_context_t avrcp_controller_context;
52 
53 static int avrcp_controller_supports_browsing(uint16_t controller_supported_features){
54     return controller_supported_features & (1 << AVRCP_CONTROLLER_SUPPORTED_FEATURE_BROWSING);
55 }
56 
57 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){
58     avrcp_create_sdp_record(1, service, service_record_handle, avrcp_controller_supports_browsing(supported_features), supported_features, service_name, service_provider_name);
59 }
60 
61 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){
62     btstack_assert(callback != NULL);
63 
64     uint8_t event[8];
65     int pos = 0;
66     event[pos++] = HCI_EVENT_AVRCP_META;
67     event[pos++] = sizeof(event) - 2;
68     event[pos++] = AVRCP_SUBEVENT_SHUFFLE_AND_REPEAT_MODE;
69     little_endian_store_16(event, pos, avrcp_cid);
70     pos += 2;
71     event[pos++] = ctype;
72     event[pos++] = repeat_mode;
73     event[pos++] = shuffle_mode;
74     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
75 }
76 
77 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){
78     btstack_assert(callback != NULL);
79 
80     uint8_t event[7];
81     int pos = 0;
82     event[pos++] = HCI_EVENT_AVRCP_META;
83     event[pos++] = sizeof(event) - 2;
84     event[pos++] = subevent;
85     little_endian_store_16(event, pos, avrcp_cid);
86     pos += 2;
87     event[pos++] = ctype;
88     event[pos++] = operation_id;
89     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
90 }
91 
92 static void avrcp_press_and_hold_timeout_handler(btstack_timer_source_t * timer){
93     UNUSED(timer);
94     avrcp_connection_t * connection = (avrcp_connection_t*) btstack_run_loop_get_timer_context(timer);
95     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
96     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
97     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
98     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
99 }
100 
101 static void avrcp_press_and_hold_timer_start(avrcp_connection_t * connection){
102     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
103     btstack_run_loop_set_timer_handler(&connection->press_and_hold_cmd_timer, avrcp_press_and_hold_timeout_handler);
104     btstack_run_loop_set_timer_context(&connection->press_and_hold_cmd_timer, connection);
105     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
106     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
107 }
108 
109 static void avrcp_press_and_hold_timer_stop(avrcp_connection_t * connection){
110     connection->continuous_fast_forward_cmd = 0;
111     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
112 }
113 
114 static uint8_t request_pass_through_release_control_cmd(avrcp_connection_t * connection){
115     connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
116     if (connection->continuous_fast_forward_cmd){
117         avrcp_press_and_hold_timer_stop(connection);
118     }
119     connection->cmd_operands[0] = 0x80 | connection->cmd_operands[0];
120     connection->transaction_label++;
121     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
122     return ERROR_CODE_SUCCESS;
123 }
124 
125 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){
126     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
127     if (!connection){
128         log_error("avrcp: could not find a connection. avrcp cid 0x%02x", avrcp_cid);
129         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
130     }
131 
132     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
133     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
134     connection->command_opcode =  AVRCP_CMD_OPCODE_PASS_THROUGH;
135     connection->command_type = AVRCP_CTYPE_CONTROL;
136     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
137     connection->subunit_id =   AVRCP_SUBUNIT_ID;
138     connection->cmd_operands_length = 0;
139 
140     connection->continuous_fast_forward_cmd = continuous_fast_forward_cmd;
141     connection->cmd_operands_length = 2;
142     connection->cmd_operands[0] = opid;
143     if (playback_speed > 0){
144         connection->cmd_operands[2] = playback_speed;
145         connection->cmd_operands_length++;
146     }
147     connection->cmd_operands[1] = connection->cmd_operands_length - 2;
148 
149     if (connection->continuous_fast_forward_cmd){
150         avrcp_press_and_hold_timer_start(connection);
151     }
152 
153     connection->transaction_label++;
154     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
155     return ERROR_CODE_SUCCESS;
156 }
157 
158 static uint8_t request_single_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
159     return request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, 0);
160 }
161 
162 static uint8_t request_continuous_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
163     return request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, 1);
164 }
165 
166 #define AVRCP_CMD_BUFFER_SIZE 30
167 static uint16_t avrcp_get_max_payload_size_for_packet_type(avrcp_packet_type_t packet_type){
168     switch (packet_type){
169         case AVRCP_SINGLE_PACKET:
170             return AVRCP_CMD_BUFFER_SIZE - 3;
171         case AVRCP_START_PACKET:
172             return AVRCP_CMD_BUFFER_SIZE - 4;
173         case AVRCP_CONTINUE_PACKET:
174         case AVRCP_END_PACKET:
175             return AVRCP_CMD_BUFFER_SIZE - 1;
176     }
177     return 0;
178 }
179 
180 static int avrcp_send_cmd(avrcp_connection_t * connection, avrcp_packet_type_t packet_type){
181     uint8_t command[AVRCP_CMD_BUFFER_SIZE];
182     int pos = 0;
183     uint16_t max_bytes = sizeof(command) - 1;
184 
185     // transport header
186     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
187     command[pos++] = (connection->transaction_label << 4) | (packet_type << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
188 
189     if (packet_type == AVRCP_START_PACKET){
190         // num packets: (3 bytes overhead (PID, num packets) + command) / (MTU - transport header)
191         command[pos++] = ((connection->cmd_operands_fragmented_len + 3 - 1) / (AVRCP_CMD_BUFFER_SIZE - 1)) + 1;
192         max_bytes -= 3;
193     }
194 
195     if ((packet_type == AVRCP_SINGLE_PACKET) || (packet_type == AVRCP_START_PACKET)){
196         // Profile IDentifier (PID)
197         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
198         command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
199 
200         // command_type
201         command[pos++] = connection->command_type;
202         // subunit_type | subunit ID
203         command[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
204         // opcode
205         command[pos++] = (uint8_t)connection->command_opcode;
206     }
207 
208     if (packet_type == AVRCP_SINGLE_PACKET){
209         // operands
210         (void)memcpy(command + pos, connection->cmd_operands,
211                      connection->cmd_operands_length);
212         pos += connection->cmd_operands_length;
213     } else {
214         uint16_t bytes_to_copy = btstack_min(connection->cmd_operands_fragmented_len-connection->cmd_operands_fragmented_pos, max_bytes);
215         (void)memcpy(command + pos,
216                      &connection->cmd_operands_fragmented_buffer[connection->cmd_operands_fragmented_pos],
217                      bytes_to_copy);
218         pos += bytes_to_copy;
219         connection->cmd_operands_fragmented_pos += bytes_to_copy;
220     }
221 
222     return l2cap_send(connection->l2cap_signaling_cid, command, pos);
223 }
224 
225 static int avrcp_register_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
226     if (connection->notifications_to_deregister & (1 << event_id)) return 0;
227     if (connection->notifications_enabled & (1 << event_id)) return 0;
228     if (connection->notifications_to_register & (1 << event_id)) return 0;
229     connection->notifications_to_register |= (1 << event_id);
230     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
231     return 1;
232 }
233 
234 static void avrcp_prepare_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
235     connection->transaction_label++;
236     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
237     connection->command_type = AVRCP_CTYPE_NOTIFY;
238     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
239     connection->subunit_id = AVRCP_SUBUNIT_ID;
240     int pos = 0;
241     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
242     pos += 3;
243     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
244     connection->cmd_operands[pos++] = 0;                     // reserved(upper 6) | packet_type -> 0
245     big_endian_store_16(connection->cmd_operands, pos, 5);     // parameter length
246     pos += 2;
247     connection->cmd_operands[pos++] = event_id;
248     big_endian_store_32(connection->cmd_operands, pos, 1); // send notification on playback position every second, for other notifications it is ignored
249     pos += 4;
250     connection->cmd_operands_length = pos;
251     // AVRCP_SPEC_V14.pdf 166
252     // answer page 61
253 }
254 
255 
256 static void avrcp_parser_reset(avrcp_connection_t * connection){
257     connection->list_offset = 0;
258     connection->num_attributes = 0;
259     connection->num_parsed_attributes = 0;
260     connection->parser_attribute_header_pos = 0;
261     connection->num_received_fragments = 0;
262     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
263 }
264 
265 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){
266     uint8_t event[7];
267     int pos = 0;
268     event[pos++] = HCI_EVENT_AVRCP_META;
269     event[pos++] = sizeof(event) - 2;
270     event[pos++] = AVRCP_SUBEVENT_NOW_PLAYING_INFO_DONE;
271     little_endian_store_16(event, pos, avrcp_cid);
272     pos += 2;
273     event[pos++] = ctype;
274     event[pos++] = status;
275     // printf_hexdump(event, pos);
276     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
277 }
278 
279 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){
280     uint8_t event[HCI_EVENT_BUFFER_SIZE];
281     int pos = 0;
282     event[pos++] = HCI_EVENT_AVRCP_META;
283     // reserve one byte for subevent type and data len
284     int data_len_pos = pos;
285     pos++;
286     int subevent_type_pos = pos;
287     pos++;
288     little_endian_store_16(event, pos, avrcp_cid);
289     pos += 2;
290     event[pos++] = ctype;
291 
292     switch (attr_id){
293         case AVRCP_MEDIA_ATTR_TITLE:
294             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TITLE_INFO;
295             event[pos++] = value_len;
296             (void)memcpy(event + pos, value, value_len);
297             break;
298         case AVRCP_MEDIA_ATTR_ARTIST:
299             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ARTIST_INFO;
300             event[pos++] = value_len;
301             (void)memcpy(event + pos, value, value_len);
302             break;
303         case AVRCP_MEDIA_ATTR_ALBUM:
304             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ALBUM_INFO;
305             event[pos++] = value_len;
306             (void)memcpy(event + pos, value, value_len);
307             break;
308         case AVRCP_MEDIA_ATTR_GENRE:
309             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_GENRE_INFO;
310             event[pos++] = value_len;
311             (void)memcpy(event + pos, value, value_len);
312             break;
313         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
314             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_SONG_LENGTH_MS_INFO;
315             if (value){
316                 little_endian_store_32(event, pos, btstack_atoi((char *)value));
317             } else {
318                 little_endian_store_32(event, pos, 0);
319             }
320             pos += 4;
321             break;
322         case AVRCP_MEDIA_ATTR_TRACK:
323             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TRACK_INFO;
324             if (value){
325                 event[pos++] = btstack_atoi((char *)value);
326             } else {
327                 event[pos++] = 0;
328             }
329             break;
330         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
331             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TOTAL_TRACKS_INFO;
332             if (value){
333                 event[pos++] = btstack_atoi((char *)value);
334             } else {
335                 event[pos++] = 0;
336             }
337             break;
338         default:
339             break;
340     }
341     event[data_len_pos] = pos - 2;
342     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
343 }
344 
345 static void avrcp_parser_process_byte(uint8_t byte, avrcp_connection_t * connection, avrcp_command_type_t ctype){
346     uint16_t attribute_total_value_len;
347     uint32_t attribute_id;
348     // printf("avrcp_parser_process_byte: %02x, state %02x\n", byte, connection->parser_state);
349     switch(connection->parser_state){
350         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:
351             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
352             connection->list_offset++;
353 
354             if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN) return;
355 
356             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
357             connection->attribute_value_len = btstack_min(attribute_total_value_len, AVRCP_MAX_ATTRIBUTTE_SIZE);
358             if (connection->attribute_value_len > 0){
359                 // get ready for attribute value
360                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
361                 return;
362             }
363 
364             // emit empty attribute
365             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
366             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);
367 
368             // done, see below
369             break;
370 
371         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:
372             connection->attribute_value[connection->attribute_value_offset++] = byte;
373             connection->list_offset++;
374 
375             if (connection->attribute_value_offset < connection->attribute_value_len) return;
376 
377             // emit (potentially partial) attribute
378             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
379             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);
380 
381             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
382             if (connection->attribute_value_offset < attribute_total_value_len){
383                 // ignore rest of attribute
384                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
385                 return;
386             }
387 
388             // done, see below
389             break;
390 
391         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
392             connection->attribute_value_offset++;
393             connection->list_offset++;
394 
395             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
396             if (connection->attribute_value_offset < attribute_total_value_len) return;
397 
398             // done, see below
399             break;
400 
401         default:
402             return;
403     }
404 
405     // attribute fully read, check if more to come
406     if (connection->list_offset < connection->list_size){
407         // more to come, reset parser
408         connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
409         connection->parser_attribute_header_pos = 0;
410         connection->attribute_value_offset = 0;
411     } else {
412         // fully done
413         avrcp_parser_reset(connection);
414         avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 0);
415     }
416 }
417 
418 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){
419     int i;
420     for (i=0;i<num_bytes_to_read;i++){
421         avrcp_parser_process_byte(packet[i], connection, ctype);
422     }
423 }
424 
425 static uint8_t avrcp_controller_request_abort_continuation(avrcp_connection_t * connection){
426     connection->state = AVCTP_W2_SEND_COMMAND;
427     connection->transaction_label++;
428     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
429     connection->command_type = AVRCP_CTYPE_CONTROL;
430     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
431     connection->subunit_id = AVRCP_SUBUNIT_ID;
432     int pos = 0;
433     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
434     pos += 3;
435     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE; // PDU ID
436     connection->cmd_operands[pos++] = 0;
437     // Parameter Length
438     connection->cmd_operands_length = 8;
439     big_endian_store_16(connection->cmd_operands, pos, 1);
440     pos += 2;
441     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
442     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
443     return ERROR_CODE_SUCCESS;
444 }
445 
446 
447 static uint8_t avrcp_controller_request_continue_response(avrcp_connection_t * connection){
448     connection->state = AVCTP_W2_SEND_COMMAND;
449     connection->transaction_label++;
450     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
451     connection->command_type = AVRCP_CTYPE_CONTROL;
452     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
453     connection->subunit_id = AVRCP_SUBUNIT_ID;
454     int pos = 0;
455     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
456     pos += 3;
457     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE; // PDU ID
458     connection->cmd_operands[pos++] = 0;
459     // Parameter Length
460     connection->cmd_operands_length = 8;
461     big_endian_store_16(connection->cmd_operands, pos, 1);
462     pos += 2;
463     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
464     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
465     return ERROR_CODE_SUCCESS;
466 }
467 
468 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
469     uint8_t operands[20];
470     uint8_t opcode;
471     int     pos = 3;
472 
473     avrcp_command_type_t ctype = (avrcp_command_type_t) packet[pos++];
474     uint8_t byte_value = packet[pos++];
475     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (byte_value >> 3);
476     avrcp_subunit_type_t subunit_id = (avrcp_subunit_type_t)   (byte_value & 0x07);
477     opcode = packet[pos++];
478 
479     uint8_t pdu_id;
480     uint16_t param_length;
481     switch (avrcp_cmd_opcode(packet,size)){
482         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
483             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
484             connection->state = AVCTP_CONNECTION_OPENED;
485             // operands:
486             (void)memcpy(operands, packet + pos, 5);
487             uint8_t unit_type = operands[1] >> 3;
488             uint8_t max_subunit_ID = operands[1] & 0x07;
489             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);
490             break;
491         }
492         case AVRCP_CMD_OPCODE_UNIT_INFO:{
493             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
494             connection->state = AVCTP_CONNECTION_OPENED;
495             // operands:
496             (void)memcpy(operands, packet + pos, 5);
497             uint8_t unit_type = operands[1] >> 3;
498             uint8_t unit = operands[1] & 0x07;
499             uint32_t company_id = (operands[2] << 16) | (operands[3] << 8) | operands[4];
500             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,
501                 ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id);
502             break;
503         }
504         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
505             if ((size - pos) < 7) {
506                 log_error("avrcp: wrong packet size");
507                 return;
508             };
509             // operands:
510             (void)memcpy(operands, packet + pos, 7);
511             pos += 7;
512             pdu_id = operands[3];
513 
514             if ((connection->state != AVCTP_W2_RECEIVE_RESPONSE) && (pdu_id != AVRCP_PDU_ID_REGISTER_NOTIFICATION)){
515                 log_info("AVRCP_CMD_OPCODE_VENDOR_DEPENDENT state %d", connection->state);
516                 return;
517             }
518             connection->state = AVCTP_CONNECTION_OPENED;
519 
520             param_length = big_endian_read_16(operands, 5);
521 
522             log_info("        VENDOR DEPENDENT response: pdu id 0x%02x, param_length %d, status %s", pdu_id, param_length, avrcp_ctype2str(ctype));
523             switch (pdu_id){
524                 case AVRCP_PDU_ID_GetCurrentPlayerApplicationSettingValue:{
525                     uint8_t num_attributes = packet[pos++];
526                     int i;
527                     avrcp_repeat_mode_t  repeat_mode =  AVRCP_REPEAT_MODE_INVALID;
528                     avrcp_shuffle_mode_t shuffle_mode = AVRCP_SHUFFLE_MODE_INVALID;
529                     for (i = 0; i < num_attributes; i++){
530                         uint8_t attribute_id    = packet[pos++];
531                         uint8_t value = packet[pos++];
532                         switch (attribute_id){
533                             case 0x02:
534                                 repeat_mode = (avrcp_repeat_mode_t) value;
535                                 break;
536                             case 0x03:
537                                 shuffle_mode = (avrcp_shuffle_mode_t) value;
538                                 break;
539                             default:
540                                 break;
541                         }
542                     }
543                     avrcp_emit_repeat_and_shuffle_mode(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, repeat_mode, shuffle_mode);
544                     break;
545                 }
546                 case AVRCP_PDU_ID_SetPlayerApplicationSettingValue:{
547                     uint8_t event[6];
548                     int offset = 0;
549                     event[offset++] = HCI_EVENT_AVRCP_META;
550                     event[offset++] = sizeof(event) - 2;
551                     event[offset++] = AVRCP_SUBEVENT_PLAYER_APPLICATION_VALUE_RESPONSE;
552                     little_endian_store_16(event, offset, connection->avrcp_cid);
553                     offset += 2;
554                     event[offset++] = ctype;
555                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
556                     break;
557                 }
558                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME:{
559                     uint8_t event[7];
560                     int offset = 0;
561                     event[offset++] = HCI_EVENT_AVRCP_META;
562                     event[offset++] = sizeof(event) - 2;
563                     event[offset++] = AVRCP_SUBEVENT_SET_ABSOLUTE_VOLUME_RESPONSE;
564                     little_endian_store_16(event, offset, connection->avrcp_cid);
565                     offset += 2;
566                     event[offset++] = ctype;
567                     event[offset++] = packet[pos++];
568                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
569                     break;
570                 }
571                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
572                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos++];
573                     uint8_t capability_count = packet[pos++];
574                     int i;
575                     switch (capability_id){
576                         case AVRCP_CAPABILITY_ID_COMPANY:
577                             for (i = 0; i < capability_count; i++){
578                                 uint32_t company_id = big_endian_read_24(packet, pos);
579                                 pos += 3;
580                                 log_info("  0x%06" PRIx32 ", ", company_id);
581                             }
582                             break;
583                         case AVRCP_CAPABILITY_ID_EVENT:
584                             for (i = 0; i < capability_count; i++){
585                                 uint8_t event_id = packet[pos++];
586                                 log_info("  0x%02x %s", event_id, avrcp_event2str(event_id));
587                             }
588                             break;
589                     }
590                     break;
591                 }
592                 case AVRCP_PDU_ID_GET_PLAY_STATUS:{
593                     uint32_t song_length = big_endian_read_32(packet, pos);
594                     pos += 4;
595                     uint32_t song_position = big_endian_read_32(packet, pos);
596                     pos += 4;
597                     uint8_t play_status = packet[pos];
598 
599                     uint8_t event[15];
600                     int offset = 0;
601                     event[offset++] = HCI_EVENT_AVRCP_META;
602                     event[offset++] = sizeof(event) - 2;
603                     event[offset++] = AVRCP_SUBEVENT_PLAY_STATUS;
604                     little_endian_store_16(event, offset, connection->avrcp_cid);
605                     offset += 2;
606                     event[offset++] = ctype;
607                     little_endian_store_32(event, offset, song_length);
608                     offset += 4;
609                     little_endian_store_32(event, offset, song_position);
610                     offset += 4;
611                     event[offset++] = play_status;
612                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
613                     break;
614                 }
615                 case AVRCP_PDU_ID_REGISTER_NOTIFICATION:{
616                     avrcp_notification_event_id_t  event_id = (avrcp_notification_event_id_t) packet[pos++];
617                     uint16_t event_mask = (1 << event_id);
618                     uint16_t reset_event_mask = ~event_mask;
619                     switch (ctype){
620                         case AVRCP_CTYPE_RESPONSE_INTERIM:
621                             // register as enabled
622                             connection->notifications_enabled |= event_mask;
623                             break;
624                         case AVRCP_CTYPE_RESPONSE_CHANGED_STABLE:
625                             // received change, event is considered deregistered
626                             // we are re-enabling it automatically, if it is not
627                             // explicitly disabled
628                             connection->notifications_enabled &= reset_event_mask;
629                             if (! (connection->notifications_to_deregister & event_mask)){
630                                 avrcp_register_notification(connection, event_id);
631                             } else {
632                                 connection->notifications_to_deregister &= reset_event_mask;
633                             }
634                             break;
635                         default:
636                             connection->notifications_to_register &= reset_event_mask;
637                             connection->notifications_enabled &= reset_event_mask;
638                             connection->notifications_to_deregister &= reset_event_mask;
639                             break;
640                     }
641 
642                     switch (event_id){
643                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_POS_CHANGED:{
644                             uint32_t song_position = big_endian_read_32(packet, pos);
645                             uint8_t event[10];
646                             int offset = 0;
647                             event[offset++] = HCI_EVENT_AVRCP_META;
648                             event[offset++] = sizeof(event) - 2;
649                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_POS_CHANGED;
650                             little_endian_store_16(event, offset, connection->avrcp_cid);
651                             offset += 2;
652                             event[offset++] = ctype;
653                             little_endian_store_32(event, offset, song_position);
654                             offset += 4;
655                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
656                             break;
657                         }
658                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:{
659                             uint8_t event[7];
660                             int offset = 0;
661                             event[offset++] = HCI_EVENT_AVRCP_META;
662                             event[offset++] = sizeof(event) - 2;
663                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_STATUS_CHANGED;
664                             little_endian_store_16(event, offset, connection->avrcp_cid);
665                             offset += 2;
666                             event[offset++] = ctype;
667                             event[offset++] = packet[pos];
668                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
669                             break;
670                         }
671                         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:{
672                             uint8_t event[6];
673                             int offset = 0;
674                             event[offset++] = HCI_EVENT_AVRCP_META;
675                             event[offset++] = sizeof(event) - 2;
676                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_TRACK_CHANGED;
677                             little_endian_store_16(event, offset, connection->avrcp_cid);
678                             offset += 2;
679                             event[offset++] = ctype;
680                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
681                             break;
682                         }
683                         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:{
684                             uint8_t event[6];
685                             int offset = 0;
686                             event[offset++] = HCI_EVENT_AVRCP_META;
687                             event[offset++] = sizeof(event) - 2;
688                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_NOW_PLAYING_CONTENT_CHANGED;
689                             little_endian_store_16(event, offset, connection->avrcp_cid);
690                             offset += 2;
691                             event[offset++] = ctype;
692                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
693                             break;
694                         }
695                         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:{
696                             uint8_t event[6];
697                             int offset = 0;
698                             event[offset++] = HCI_EVENT_AVRCP_META;
699                             event[offset++] = sizeof(event) - 2;
700                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_AVAILABLE_PLAYERS_CHANGED;
701                             little_endian_store_16(event, offset, connection->avrcp_cid);
702                             offset += 2;
703                             event[offset++] = ctype;
704                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
705                             break;
706                         }
707                         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:{
708                             uint8_t event[7];
709                             int offset = 0;
710                             event[offset++] = HCI_EVENT_AVRCP_META;
711                             event[offset++] = sizeof(event) - 2;
712                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
713                             little_endian_store_16(event, offset, connection->avrcp_cid);
714                             offset += 2;
715                             event[offset++] = ctype;
716                             event[offset++] = packet[pos++] & 0x7F;
717                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
718                             break;
719                         }
720                         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:{
721                             uint8_t event[7];
722                             int offset = 0;
723                             event[offset++] = HCI_EVENT_AVRCP_META;
724                             event[offset++] = sizeof(event) - 2;
725                             event[offset++] = AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED;
726                             little_endian_store_16(event, offset, connection->avrcp_cid);
727                             offset += 2;
728                             event[offset++] = ctype;
729                             event[offset++] = packet[pos++] & 0x7F;
730                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
731                             break;
732                         }
733 
734                         default:
735                             log_info("avrcp: not implemented");
736                             break;
737                     }
738                     if (connection->notifications_to_register != 0){
739                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
740                     }
741                     break;
742                 }
743 
744                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
745                     avrcp_packet_type_t packet_type = (avrcp_packet_type_t) (operands[4] & 0x03);
746                     switch (packet_type){
747                         case AVRCP_START_PACKET:
748                         case AVRCP_SINGLE_PACKET:
749                             avrcp_parser_reset(connection);
750                             connection->list_size = param_length;
751                             connection->num_attributes = packet[pos++];
752 
753                             avrcp_source_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
754 
755                             if (packet_type == AVRCP_START_PACKET){
756                                 avrcp_controller_request_continue_response(connection);
757                             }
758                             break;
759                         case AVRCP_CONTINUE_PACKET:
760                         case AVRCP_END_PACKET:
761                             connection->num_received_fragments++;
762                             if (connection->num_received_fragments < connection->max_num_fragments){
763                                 avrcp_source_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
764                                 if (packet_type == AVRCP_CONTINUE_PACKET){
765                                     avrcp_controller_request_continue_response(connection);
766                                 }
767                             } else {
768                                 avrcp_controller_request_abort_continuation(connection);
769                                 avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 1);
770                                 avrcp_parser_reset(connection);
771                             }
772                             break;
773                     }
774                 }
775                 default:
776                     break;
777             }
778             break;
779         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
780             // 0x80 | connection->cmd_operands[0]
781             uint8_t operation_id = packet[pos++];
782             switch (connection->state){
783                 case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
784                     if (connection->continuous_fast_forward_cmd){
785                         connection->state = AVCTP_W4_STOP;
786                     } else {
787                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
788                     }
789                     break;
790                 case AVCTP_W2_RECEIVE_RESPONSE:
791                     connection->state = AVCTP_CONNECTION_OPENED;
792                     break;
793                 default:
794                     break;
795             }
796             if (connection->state == AVCTP_W4_STOP){
797                 avrcp_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_START, connection->avrcp_cid, ctype, operation_id);
798             }
799             if (connection->state == AVCTP_CONNECTION_OPENED) {
800                 // RELEASE response
801                 operation_id = operation_id & 0x7F;
802                 avrcp_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_COMPLETE, connection->avrcp_cid, ctype, operation_id);
803             }
804             if (connection->state == AVCTP_W2_SEND_RELEASE_COMMAND){
805                 // PRESS response
806                 request_pass_through_release_control_cmd(connection);
807             }
808             break;
809         }
810         default:
811             break;
812     }
813 
814     // trigger pending notification reqistrations
815     if ((connection->state == AVCTP_CONNECTION_OPENED) && connection->notifications_to_register){
816         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
817     }
818 }
819 
820 static void avrcp_controller_handle_can_send_now(avrcp_connection_t * connection){
821     int i;
822     switch (connection->state){
823         case AVCTP_W2_SEND_PRESS_COMMAND:
824             connection->state = AVCTP_W2_RECEIVE_PRESS_RESPONSE;
825             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
826             break;
827         case AVCTP_W2_SEND_COMMAND:
828         case AVCTP_W2_SEND_RELEASE_COMMAND:
829             connection->state = AVCTP_W2_RECEIVE_RESPONSE;
830             avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
831             break;
832         case AVCTP_CONNECTION_OPENED:
833             if (connection->notifications_to_register != 0){
834                 for (i = 1; i <= AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED; i++){
835                     if (connection->notifications_to_register & (1<<i)){
836                         connection->notifications_to_register &= ~ (1 << i);
837                         avrcp_prepare_notification(connection, (avrcp_notification_event_id_t) i);
838                         connection->state = AVCTP_W2_RECEIVE_RESPONSE;
839                         avrcp_send_cmd(connection, AVRCP_SINGLE_PACKET);
840                         return;
841                     }
842                 }
843             }
844             return;
845         case AVCTP_W2_SEND_FRAGMENTED_COMMAND:
846             if (connection->cmd_operands_fragmented_pos == 0){
847                  avrcp_send_cmd(connection, AVRCP_START_PACKET);
848                  avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
849             } else {
850                 if ((connection->cmd_operands_fragmented_len - connection->cmd_operands_fragmented_pos) > avrcp_get_max_payload_size_for_packet_type(AVRCP_CONTINUE_PACKET)){
851                      avrcp_send_cmd(connection, AVRCP_CONTINUE_PACKET);
852                      avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
853                  } else {
854                     connection->state = AVCTP_W2_RECEIVE_RESPONSE;
855                     avrcp_send_cmd(connection, AVRCP_END_PACKET);
856                  }
857             }
858         default:
859             return;
860     }
861 }
862 
863 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
864     avrcp_connection_t * connection;
865 
866     switch (packet_type) {
867         case L2CAP_DATA_PACKET:
868             connection = get_avrcp_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
869             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
870             break;
871 
872         case HCI_EVENT_PACKET:
873             switch (hci_event_packet_get_type(packet)){
874                 case L2CAP_EVENT_CAN_SEND_NOW:
875                     connection = get_avrcp_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, channel);
876                     avrcp_controller_handle_can_send_now(connection);
877                     break;
878             default:
879                 break;
880         }
881         default:
882             break;
883     }
884 }
885 
886 void avrcp_controller_init(void){
887     avrcp_controller_context.role = AVRCP_CONTROLLER;
888     avrcp_controller_context.packet_handler = avrcp_controller_packet_handler;
889     avrcp_register_controller_packet_handler(&avrcp_controller_packet_handler);
890 }
891 
892 void avrcp_controller_register_packet_handler(btstack_packet_handler_t callback){
893     btstack_assert(callback != NULL);
894     avrcp_controller_context.avrcp_callback = callback;
895 }
896 
897 uint8_t avrcp_controller_unit_info(uint16_t avrcp_cid){
898     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
899     if (!connection){
900         log_error("avrcp_unit_info: could not find a connection.");
901         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
902     }
903     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
904     connection->state = AVCTP_W2_SEND_COMMAND;
905 
906     connection->transaction_label++;
907     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
908     connection->command_type = AVRCP_CTYPE_STATUS;
909     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
910     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
911     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
912     connection->cmd_operands_length = 5;
913     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
914     return ERROR_CODE_SUCCESS;
915 }
916 
917 uint8_t avrcp_controller_subunit_info(uint16_t avrcp_cid){
918     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
919     if (!connection){
920         log_error("avrcp_unit_info: could not find a connection.");
921         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
922     }
923     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
924     connection->state = AVCTP_W2_SEND_COMMAND;
925 
926     connection->transaction_label++;
927     connection->command_opcode = AVRCP_CMD_OPCODE_SUBUNIT_INFO;
928     connection->command_type = AVRCP_CTYPE_STATUS;
929     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
930     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
931     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
932     connection->cmd_operands[0] = 7; // page: 0, extention_code: 7
933     connection->cmd_operands_length = 5;
934     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
935     return ERROR_CODE_SUCCESS;
936 }
937 
938 static uint8_t avrcp_controller_get_capabilities(uint16_t avrcp_cid, uint8_t capability_id){
939     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
940     if (!connection){
941         log_error("avrcp_get_capabilities: could not find a connection.");
942         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
943     }
944     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
945     connection->state = AVCTP_W2_SEND_COMMAND;
946 
947     connection->transaction_label++;
948     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
949     connection->command_type = AVRCP_CTYPE_STATUS;
950     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
951     connection->subunit_id = AVRCP_SUBUNIT_ID;
952     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
953     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CAPABILITIES; // PDU ID
954     connection->cmd_operands[4] = 0;
955     big_endian_store_16(connection->cmd_operands, 5, 1); // parameter length
956     connection->cmd_operands[7] = capability_id;                  // capability ID
957     connection->cmd_operands_length = 8;
958     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
959     return ERROR_CODE_SUCCESS;
960 }
961 
962 uint8_t avrcp_controller_get_supported_company_ids(uint16_t avrcp_cid){
963     return avrcp_controller_get_capabilities(avrcp_cid, AVRCP_CAPABILITY_ID_COMPANY);
964 }
965 
966 uint8_t avrcp_controller_get_supported_events(uint16_t avrcp_cid){
967     return avrcp_controller_get_capabilities(avrcp_cid, AVRCP_CAPABILITY_ID_EVENT);
968 }
969 
970 
971 uint8_t avrcp_controller_play(uint16_t avrcp_cid){
972     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
973 }
974 
975 uint8_t avrcp_controller_stop(uint16_t avrcp_cid){
976     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
977 }
978 
979 uint8_t avrcp_controller_pause(uint16_t avrcp_cid){
980     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
981 }
982 
983 uint8_t avrcp_controller_forward(uint16_t avrcp_cid){
984     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
985 }
986 
987 uint8_t avrcp_controller_backward(uint16_t avrcp_cid){
988     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
989 }
990 
991 uint8_t avrcp_controller_volume_up(uint16_t avrcp_cid){
992     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
993 }
994 
995 uint8_t avrcp_controller_volume_down(uint16_t avrcp_cid){
996     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
997 }
998 
999 uint8_t avrcp_controller_mute(uint16_t avrcp_cid){
1000     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1001 }
1002 
1003 uint8_t avrcp_controller_skip(uint16_t avrcp_cid){
1004     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_SKIP, 0);
1005 }
1006 
1007 uint8_t avrcp_controller_fast_forward(uint16_t avrcp_cid){
1008     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1009 }
1010 
1011 uint8_t avrcp_controller_rewind(uint16_t avrcp_cid){
1012     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1013 }
1014 
1015 
1016 /* start cmds */
1017 
1018 uint8_t avrcp_controller_release_press_and_hold_cmd(uint16_t avrcp_cid){
1019     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1020     if (!connection){
1021         log_error("avrcp_stop_play: could not find a connection.");
1022         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1023     }
1024     if (connection->state != AVCTP_W4_STOP) return ERROR_CODE_COMMAND_DISALLOWED;
1025     return request_pass_through_release_control_cmd(connection);
1026 }
1027 
1028 uint8_t avrcp_controller_press_and_hold_play(uint16_t avrcp_cid){
1029     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
1030 }
1031 uint8_t avrcp_controller_press_and_hold_stop(uint16_t avrcp_cid){
1032     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
1033 }
1034 uint8_t avrcp_controller_press_and_hold_pause(uint16_t avrcp_cid){
1035     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
1036 }
1037 uint8_t avrcp_controller_press_and_hold_forward(uint16_t avrcp_cid){
1038     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
1039 }
1040 uint8_t avrcp_controller_press_and_hold_backward(uint16_t avrcp_cid){
1041     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
1042 }
1043 uint8_t avrcp_controller_press_and_hold_fast_forward(uint16_t avrcp_cid){
1044     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1045 }
1046 uint8_t avrcp_controller_press_and_hold_rewind(uint16_t avrcp_cid){
1047     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1048 }
1049 uint8_t avrcp_controller_press_and_hold_volume_up(uint16_t avrcp_cid){
1050     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
1051 }
1052 uint8_t avrcp_controller_press_and_hold_volume_down(uint16_t avrcp_cid){
1053     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
1054 }
1055 uint8_t avrcp_controller_press_and_hold_mute(uint16_t avrcp_cid){
1056     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
1057 }
1058 
1059 
1060 /* stop continuous cmds */
1061 
1062 uint8_t avrcp_controller_get_play_status(uint16_t avrcp_cid){
1063     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1064     if (!connection){
1065         log_error("avrcp_get_play_status: could not find a connection.");
1066         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1067     }
1068     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1069     connection->state = AVCTP_W2_SEND_COMMAND;
1070     connection->transaction_label++;
1071     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1072     connection->command_type = AVRCP_CTYPE_STATUS;
1073     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1074     connection->subunit_id = AVRCP_SUBUNIT_ID;
1075     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1076     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_PLAY_STATUS;
1077     connection->cmd_operands[4] = 0;                     // reserved(upper 6) | packet_type -> 0
1078     big_endian_store_16(connection->cmd_operands, 5, 0); // parameter length
1079     connection->cmd_operands_length = 7;
1080     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1081     return ERROR_CODE_SUCCESS;
1082 }
1083 
1084 uint8_t avrcp_controller_enable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1085     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1086     if (!connection){
1087         log_error("avrcp_get_play_status: could not find a connection.");
1088         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1089     }
1090     avrcp_register_notification(connection, event_id);
1091     return ERROR_CODE_SUCCESS;
1092 }
1093 
1094 uint8_t avrcp_controller_disable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1095     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1096     if (!connection){
1097         log_error("avrcp_get_play_status: could not find a connection.");
1098         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1099     }
1100     connection->notifications_to_deregister |= (1 << event_id);
1101     return ERROR_CODE_SUCCESS;
1102 }
1103 
1104 uint8_t avrcp_controller_set_addressed_player(uint16_t avrcp_cid, uint16_t addressed_player_id){
1105     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1106     if (!connection){
1107         log_error("avrcp_get_capabilities: could not find a connection.");
1108         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1109     }
1110     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1111     connection->state = AVCTP_W2_SEND_COMMAND;
1112 
1113     connection->transaction_label++;
1114     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1115     connection->command_type = AVRCP_CTYPE_CONTROL;
1116     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1117     connection->subunit_id = AVRCP_SUBUNIT_ID;
1118     int pos = 0;
1119     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1120     pos += 3;
1121     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ADDRESSED_PLAYER; // PDU ID
1122     connection->cmd_operands[pos++] = 0;
1123 
1124     // Parameter Length
1125     big_endian_store_16(connection->cmd_operands, pos, 2);
1126     pos += 2;
1127 
1128     big_endian_store_16(connection->cmd_operands, pos, addressed_player_id);
1129     pos += 2;
1130 
1131     connection->cmd_operands_length = pos;
1132     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1133     return ERROR_CODE_SUCCESS;
1134 }
1135 
1136 uint8_t avrcp_controller_get_now_playing_info(uint16_t avrcp_cid){
1137     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1138     if (!connection){
1139         log_error("avrcp_get_capabilities: could not find a connection.");
1140         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1141     }
1142     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1143     connection->state = AVCTP_W2_SEND_COMMAND;
1144 
1145     connection->transaction_label++;
1146     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1147     connection->command_type = AVRCP_CTYPE_STATUS;
1148     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1149     connection->subunit_id = AVRCP_SUBUNIT_ID;
1150     int pos = 0;
1151     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1152     pos += 3;
1153     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES; // PDU ID
1154     connection->cmd_operands[pos++] = 0;
1155 
1156     // Parameter Length
1157     big_endian_store_16(connection->cmd_operands, pos, 9);
1158     pos += 2;
1159 
1160     // write 8 bytes value
1161     memset(connection->cmd_operands + pos, 0, 8); // identifier: PLAYING
1162     pos += 8;
1163 
1164     connection->cmd_operands[pos++] = 0; // attribute count, if 0 get all attributes
1165     // every attribute is 4 bytes long
1166 
1167     connection->cmd_operands_length = pos;
1168     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1169     return ERROR_CODE_SUCCESS;
1170 }
1171 
1172 uint8_t avrcp_controller_set_absolute_volume(uint16_t avrcp_cid, uint8_t volume){
1173      avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1174     if (!connection){
1175         log_error("avrcp_get_capabilities: could not find a connection.");
1176         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1177     }
1178     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1179     connection->state = AVCTP_W2_SEND_COMMAND;
1180 
1181     connection->transaction_label++;
1182     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1183     connection->command_type = AVRCP_CTYPE_CONTROL;
1184     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1185     connection->subunit_id = AVRCP_SUBUNIT_ID;
1186     int pos = 0;
1187     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1188     pos += 3;
1189     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME; // PDU ID
1190     connection->cmd_operands[pos++] = 0;
1191 
1192     // Parameter Length
1193     big_endian_store_16(connection->cmd_operands, pos, 1);
1194     pos += 2;
1195     connection->cmd_operands[pos++] = volume;
1196 
1197     connection->cmd_operands_length = pos;
1198     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1199     return ERROR_CODE_SUCCESS;
1200 }
1201 
1202 uint8_t avrcp_controller_query_shuffle_and_repeat_modes(uint16_t avrcp_cid){
1203     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1204     if (!connection){
1205         log_error("avrcp_get_capabilities: could not find a connection.");
1206         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1207     }
1208     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1209     connection->state = AVCTP_W2_SEND_COMMAND;
1210 
1211     connection->transaction_label++;
1212     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1213     connection->command_type = AVRCP_CTYPE_STATUS;
1214     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1215     connection->subunit_id = AVRCP_SUBUNIT_ID;
1216     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1217     connection->cmd_operands[3] = AVRCP_PDU_ID_GetCurrentPlayerApplicationSettingValue; // PDU ID
1218     connection->cmd_operands[4] = 0;
1219     big_endian_store_16(connection->cmd_operands, 5, 5); // parameter length
1220     connection->cmd_operands[7] = 4;                     // NumPlayerApplicationSettingAttributeID
1221     // PlayerApplicationSettingAttributeID1 AVRCP Spec, Appendix F, 133
1222     connection->cmd_operands[8]  = 0x01;    // equalizer  (1-OFF, 2-ON)
1223     connection->cmd_operands[9]  = 0x02;    // repeat     (1-off, 2-single track, 3-all tracks, 4-group repeat)
1224     connection->cmd_operands[10] = 0x03;    // shuffle    (1-off, 2-all tracks, 3-group shuffle)
1225     connection->cmd_operands[11] = 0x04;    // scan       (1-off, 2-all tracks, 3-group scan)
1226     connection->cmd_operands_length = 12;
1227     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1228     return ERROR_CODE_SUCCESS;
1229 }
1230 
1231 static uint8_t avrcp_controller_set_current_player_application_setting_value(uint16_t avrcp_cid, uint8_t attr_id, uint8_t attr_value){
1232     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1233     if (!connection){
1234         log_error("avrcp_get_capabilities: could not find a connection.");
1235         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1236     }
1237     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1238     connection->state = AVCTP_W2_SEND_COMMAND;
1239 
1240     connection->transaction_label++;
1241     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1242     connection->command_type = AVRCP_CTYPE_CONTROL;
1243     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1244     connection->subunit_id = AVRCP_SUBUNIT_ID;
1245     int pos = 0;
1246     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1247     pos += 3;
1248     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SetPlayerApplicationSettingValue; // PDU ID
1249     connection->cmd_operands[pos++] = 0;
1250     // Parameter Length
1251     big_endian_store_16(connection->cmd_operands, pos, 3);
1252     pos += 2;
1253     connection->cmd_operands[pos++] = 2;
1254     connection->cmd_operands_length = pos;
1255     connection->cmd_operands[pos++]  = attr_id;
1256     connection->cmd_operands[pos++]  = attr_value;
1257     connection->cmd_operands_length = pos;
1258     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1259     return ERROR_CODE_SUCCESS;
1260 }
1261 
1262 uint8_t avrcp_controller_set_shuffle_mode(uint16_t avrcp_cid, avrcp_shuffle_mode_t mode){
1263     if ((mode < AVRCP_SHUFFLE_MODE_OFF) || (mode > AVRCP_SHUFFLE_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1264     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x03, mode);
1265 }
1266 
1267 uint8_t avrcp_controller_set_repeat_mode(uint16_t avrcp_cid, avrcp_repeat_mode_t mode){
1268     if ((mode < AVRCP_REPEAT_MODE_OFF) || (mode > AVRCP_REPEAT_MODE_GROUP)) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1269     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x02, mode);
1270 }
1271 
1272 uint8_t avrcp_controller_play_item_for_scope(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1273     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1274     if (!connection){
1275         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1276         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1277     }
1278     if (connection->state != AVCTP_CONNECTION_OPENED){
1279         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1280         return ERROR_CODE_COMMAND_DISALLOWED;
1281     }
1282     connection->state = AVCTP_W2_SEND_COMMAND;
1283 
1284     connection->transaction_label++;
1285     connection->command_type = AVRCP_CTYPE_CONTROL;
1286     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1287     connection->subunit_id = AVRCP_SUBUNIT_ID;
1288     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1289     int pos = 0;
1290     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1291     pos += 3;
1292     connection->cmd_operands[pos++] = AVRCP_PDU_ID_PLAY_ITEM; // PDU ID
1293     // reserved
1294     connection->cmd_operands[pos++] = 0;
1295     // Parameter Length
1296     big_endian_store_16(connection->cmd_operands, pos, 11);
1297     pos += 2;
1298     connection->cmd_operands[pos++]  = scope;
1299     memset(&connection->cmd_operands[pos], 0, 8);
1300     if (uid){
1301         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1302     }
1303     pos += 8;
1304     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1305     pos += 2;
1306     connection->cmd_operands_length = pos;
1307 
1308     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1309     return ERROR_CODE_SUCCESS;
1310 }
1311 
1312 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){
1313     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1314     if (!connection){
1315         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1316         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1317     }
1318     if (connection->state != AVCTP_CONNECTION_OPENED){
1319         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1320         return ERROR_CODE_COMMAND_DISALLOWED;
1321     }
1322     connection->state = AVCTP_W2_SEND_COMMAND;
1323 
1324     connection->transaction_label++;
1325     connection->command_type = AVRCP_CTYPE_CONTROL;
1326     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1327     connection->subunit_id = AVRCP_SUBUNIT_ID;
1328     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1329     int pos = 0;
1330     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1331     pos += 3;
1332     connection->cmd_operands[pos++] = AVRCP_PDU_ID_ADD_TO_NOW_PLAYING; // PDU ID
1333     // reserved
1334     connection->cmd_operands[pos++] = 0;
1335     // Parameter Length
1336     big_endian_store_16(connection->cmd_operands, pos, 11);
1337     pos += 2;
1338     connection->cmd_operands[pos++]  = scope;
1339     memset(&connection->cmd_operands[pos], 0, 8);
1340     if (uid){
1341         (void)memcpy(&connection->cmd_operands[pos], uid, 8);
1342     }
1343     pos += 8;
1344     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1345     pos += 2;
1346     connection->cmd_operands_length = pos;
1347 
1348     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1349     return ERROR_CODE_SUCCESS;
1350 }
1351 
1352 uint8_t avrcp_controller_set_max_num_fragments(uint16_t avrcp_cid, uint8_t max_num_fragments){
1353     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1354     if (!connection){
1355         log_error("avrcp_controller_play_item: could not find a connection.");
1356         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1357     }
1358     connection->max_num_fragments = max_num_fragments;
1359     return ERROR_CODE_SUCCESS;
1360 }
1361 
1362 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){
1363     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1364     if (!connection){
1365         log_error("avrcp_controller_play_item: could not find a connection.");
1366         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1367     }
1368 
1369     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1370     connection->state = AVCTP_W2_SEND_FRAGMENTED_COMMAND;
1371 
1372     connection->transaction_label++;
1373     connection->command_opcode = command_opcode;
1374     connection->command_type = command_type;
1375     connection->subunit_type = subunit_type;
1376     connection->subunit_id = subunit_id;
1377     connection->cmd_operands_fragmented_buffer = command_buffer;
1378     connection->cmd_operands_fragmented_pos = 0;
1379     connection->cmd_operands_fragmented_len = command_len;
1380 
1381     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1382     return ERROR_CODE_SUCCESS;
1383 }
1384