xref: /btstack/src/classic/avrcp_controller.c (revision 7f803253e97f2b458b3f47d8acd66ae21f09d122)
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 void avrcp_controller_create_sdp_record(uint8_t * service, uint32_t service_record_handle, uint8_t browsing, uint16_t supported_features, const char * service_name, const char * service_provider_name){
54     avrcp_create_sdp_record(1, service, service_record_handle, browsing, supported_features, service_name, service_provider_name);
55 }
56 
57 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){
58     if (!callback) return;
59     uint8_t event[8];
60     int pos = 0;
61     event[pos++] = HCI_EVENT_AVRCP_META;
62     event[pos++] = sizeof(event) - 2;
63     event[pos++] = AVRCP_SUBEVENT_SHUFFLE_AND_REPEAT_MODE;
64     little_endian_store_16(event, pos, avrcp_cid);
65     pos += 2;
66     event[pos++] = ctype;
67     event[pos++] = repeat_mode;
68     event[pos++] = shuffle_mode;
69     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
70 }
71 
72 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){
73     if (!callback) return;
74     uint8_t event[7];
75     int pos = 0;
76     event[pos++] = HCI_EVENT_AVRCP_META;
77     event[pos++] = sizeof(event) - 2;
78     event[pos++] = subevent;
79     little_endian_store_16(event, pos, avrcp_cid);
80     pos += 2;
81     event[pos++] = ctype;
82     event[pos++] = operation_id;
83     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
84 }
85 
86 static void avrcp_press_and_hold_timeout_handler(btstack_timer_source_t * timer){
87     UNUSED(timer);
88     avrcp_connection_t * connection = btstack_run_loop_get_timer_context(timer);
89     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
90     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
91     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
92     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
93 }
94 
95 static void avrcp_press_and_hold_timer_start(avrcp_connection_t * connection){
96     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
97     btstack_run_loop_set_timer_handler(&connection->press_and_hold_cmd_timer, avrcp_press_and_hold_timeout_handler);
98     btstack_run_loop_set_timer_context(&connection->press_and_hold_cmd_timer, connection);
99     btstack_run_loop_set_timer(&connection->press_and_hold_cmd_timer, 2000); // 2 seconds timeout
100     btstack_run_loop_add_timer(&connection->press_and_hold_cmd_timer);
101 }
102 
103 static void avrcp_press_and_hold_timer_stop(avrcp_connection_t * connection){
104     connection->continuous_fast_forward_cmd = 0;
105     btstack_run_loop_remove_timer(&connection->press_and_hold_cmd_timer);
106 }
107 
108 static uint8_t request_pass_through_release_control_cmd(avrcp_connection_t * connection){
109     connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
110     if (connection->continuous_fast_forward_cmd){
111         avrcp_press_and_hold_timer_stop(connection);
112     }
113     connection->cmd_operands[0] = 0x80 | connection->cmd_operands[0];
114     connection->transaction_label++;
115     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
116     return ERROR_CODE_SUCCESS;
117 }
118 
119 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, avrcp_context_t * context){
120     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, context);
121     if (!connection){
122         log_error("avrcp: could not find a connection.");
123         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
124     }
125     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
126     connection->state = AVCTP_W2_SEND_PRESS_COMMAND;
127     connection->command_opcode =  AVRCP_CMD_OPCODE_PASS_THROUGH;
128     connection->command_type = AVRCP_CTYPE_CONTROL;
129     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
130     connection->subunit_id =   AVRCP_SUBUNIT_ID;
131     connection->cmd_operands_length = 0;
132 
133     connection->continuous_fast_forward_cmd = continuous_fast_forward_cmd;
134     connection->cmd_operands_length = 2;
135     connection->cmd_operands[0] = opid;
136     if (playback_speed > 0){
137         connection->cmd_operands[2] = playback_speed;
138         connection->cmd_operands_length++;
139     }
140     connection->cmd_operands[1] = connection->cmd_operands_length - 2;
141 
142     if (connection->continuous_fast_forward_cmd){
143         avrcp_press_and_hold_timer_start(connection);
144     }
145 
146     connection->transaction_label++;
147     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
148     return ERROR_CODE_SUCCESS;
149 }
150 
151 static uint8_t request_single_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
152     return request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, 0, &avrcp_controller_context);
153 }
154 
155 static uint8_t request_continuous_pass_through_press_control_cmd(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint16_t playback_speed){
156     return request_pass_through_press_control_cmd(avrcp_cid, opid, playback_speed, 1, &avrcp_controller_context);
157 }
158 
159 static int avrcp_send_cmd(uint16_t cid, avrcp_connection_t * connection){
160     uint8_t command[30];
161     int pos = 0;
162 
163     // transport header
164     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
165     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
166     // Profile IDentifier (PID)
167     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
168     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
169 
170     // command_type
171     command[pos++] = connection->command_type;
172     // subunit_type | subunit ID
173     command[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
174     // opcode
175     command[pos++] = (uint8_t)connection->command_opcode;
176     // operands
177     memcpy(command+pos, connection->cmd_operands, connection->cmd_operands_length);
178     pos += connection->cmd_operands_length;
179 
180     return l2cap_send(cid, command, pos);
181 }
182 
183 static int avrcp_register_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
184     if (connection->notifications_to_deregister & (1 << event_id)) return 0;
185     if (connection->notifications_enabled & (1 << event_id)) return 0;
186     if (connection->notifications_to_register & (1 << event_id)) return 0;
187     connection->notifications_to_register |= (1 << event_id);
188     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
189     return 1;
190 }
191 
192 static void avrcp_prepare_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t event_id){
193     connection->transaction_label++;
194     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
195     connection->command_type = AVRCP_CTYPE_NOTIFY;
196     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
197     connection->subunit_id = AVRCP_SUBUNIT_ID;
198     int pos = 0;
199     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
200     pos += 3;
201     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
202     connection->cmd_operands[pos++] = 0;                     // reserved(upper 6) | packet_type -> 0
203     big_endian_store_16(connection->cmd_operands, pos, 5);     // parameter length
204     pos += 2;
205     connection->cmd_operands[pos++] = event_id;
206     big_endian_store_32(connection->cmd_operands, pos, 0);
207     pos += 4;
208     connection->cmd_operands_length = pos;
209     // AVRCP_SPEC_V14.pdf 166
210     // answer page 61
211 }
212 
213 
214 static void avrcp_parser_reset(avrcp_connection_t * connection){
215     connection->list_offset = 0;
216     connection->num_attributes = 0;
217     connection->num_parsed_attributes = 0;
218     connection->parser_attribute_header_pos = 0;
219     connection->num_received_fragments = 0;
220     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
221 }
222 
223 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){
224     uint8_t event[7];
225     int pos = 0;
226     event[pos++] = HCI_EVENT_AVRCP_META;
227     event[pos++] = sizeof(event) - 2;
228     event[pos++] = AVRCP_SUBEVENT_NOW_PLAYING_INFO_DONE;
229     little_endian_store_16(event, pos, avrcp_cid);
230     pos += 2;
231     event[pos++] = ctype;
232     event[pos++] = status;
233     // printf_hexdump(event, pos);
234     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
235 }
236 
237 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){
238     uint8_t event[HCI_EVENT_BUFFER_SIZE];
239     int pos = 0;
240     event[pos++] = HCI_EVENT_AVRCP_META;
241     // reserve one byte for subevent type and data len
242     int data_len_pos = pos;
243     pos++;
244     int subevent_type_pos = pos;
245     pos++;
246     little_endian_store_16(event, pos, avrcp_cid);
247     pos += 2;
248     event[pos++] = ctype;
249 
250     switch (attr_id){
251         case AVRCP_MEDIA_ATTR_TITLE:
252             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TITLE_INFO;
253             event[pos++] = value_len;
254             memcpy(event+pos, value, value_len);
255             break;
256         case AVRCP_MEDIA_ATTR_ARTIST:
257             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ARTIST_INFO;
258             event[pos++] = value_len;
259             memcpy(event+pos, value, value_len);
260             break;
261         case AVRCP_MEDIA_ATTR_ALBUM:
262             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_ALBUM_INFO;
263             event[pos++] = value_len;
264             memcpy(event+pos, value, value_len);
265             break;
266         case AVRCP_MEDIA_ATTR_GENRE:
267             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_GENRE_INFO;
268             event[pos++] = value_len;
269             memcpy(event+pos, value, value_len);
270             break;
271         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
272             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_SONG_LENGTH_MS_INFO;
273             if (value){
274                 little_endian_store_32(event, pos, btstack_atoi((char *)value));
275             } else {
276                 little_endian_store_32(event, pos, 0);
277             }
278             pos += 4;
279             break;
280         case AVRCP_MEDIA_ATTR_TRACK:
281             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TRACK_INFO;
282             if (value){
283                 event[pos++] = btstack_atoi((char *)value);
284             } else {
285                 event[pos++] = 0;
286             }
287             break;
288         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
289             event[subevent_type_pos] = AVRCP_SUBEVENT_NOW_PLAYING_TOTAL_TRACKS_INFO;
290             if (value){
291                 event[pos++] = btstack_atoi((char *)value);
292             } else {
293                 event[pos++] = 0;
294             }
295             break;
296         default:
297             break;
298     }
299     event[data_len_pos] = pos - 2;
300     // printf("send attr len %d,  value %s\n", value_len, value);
301     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
302 }
303 
304 static void avrcp_parser_process_byte(uint8_t byte, avrcp_connection_t * connection, avrcp_command_type_t ctype){
305     uint16_t attribute_total_value_len;
306     uint32_t attribute_id;
307     switch(connection->parser_state){
308         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:
309             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
310             connection->list_offset++;
311 
312             if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN) return;
313 
314             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
315             connection->attribute_value_len = btstack_min(attribute_total_value_len, AVRCP_MAX_ATTRIBUTTE_SIZE);
316             if (connection->attribute_value_len > 0){
317                 // get ready for attribute value
318                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
319                 return;
320             }
321 
322             // emit empty attribute
323             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
324             avrcp_controller_emit_now_playing_info_event(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, attribute_id, connection->attribute_value, connection->attribute_value_len);
325 
326             // done, see below
327             break;
328 
329         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:
330             connection->attribute_value[connection->attribute_value_offset++] = byte;
331             connection->list_offset++;
332 
333             if (connection->attribute_value_offset < connection->attribute_value_len) return;
334 
335             // emit (potentially partial) attribute
336             attribute_id = big_endian_read_32(connection->parser_attribute_header, 0);
337             avrcp_controller_emit_now_playing_info_event(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, attribute_id, connection->attribute_value, connection->attribute_value_len);
338 
339             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
340             if (connection->attribute_value_offset < attribute_total_value_len){
341                 // ignore rest of attribute
342                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
343                 return;
344             }
345 
346             // done, see below
347             break;
348 
349         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
350             connection->attribute_value_offset++;
351             connection->list_offset++;
352 
353             attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 6);
354             if (connection->attribute_value_offset < attribute_total_value_len) return;
355 
356             // done, see below
357             break;
358 
359         default:
360             return;
361     }
362 
363     // attribute fully read, check if more to come
364     if (connection->list_offset < connection->list_size){
365         // more to come, reset parser
366         connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
367         connection->parser_attribute_header_pos = 0;
368     } else {
369         // fully done
370         avrcp_parser_reset(connection);
371         avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 0);
372     }
373 }
374 
375 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){
376     int i;
377     for (i=0;i<num_bytes_to_read;i++){
378         avrcp_parser_process_byte(packet[i], connection, ctype);
379     }
380 }
381 
382 static uint8_t avrcp_controller_request_abort_continuation(avrcp_connection_t * connection){
383     connection->state = AVCTP_W2_SEND_COMMAND;
384     connection->transaction_label++;
385     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
386     connection->command_type = AVRCP_CTYPE_CONTROL;
387     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
388     connection->subunit_id = AVRCP_SUBUNIT_ID;
389     int pos = 0;
390     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
391     pos += 3;
392     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE; // PDU ID
393     connection->cmd_operands[pos++] = 0;
394     // Parameter Length
395     connection->cmd_operands_length = 8;
396     big_endian_store_16(connection->cmd_operands, pos, 1);
397     pos += 2;
398     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
399     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
400     return ERROR_CODE_SUCCESS;
401 }
402 
403 
404 static uint8_t avrcp_controller_request_continue_response(avrcp_connection_t * connection){
405     connection->state = AVCTP_W2_SEND_COMMAND;
406     connection->transaction_label++;
407     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
408     connection->command_type = AVRCP_CTYPE_CONTROL;
409     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
410     connection->subunit_id = AVRCP_SUBUNIT_ID;
411     int pos = 0;
412     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
413     pos += 3;
414     connection->cmd_operands[pos++] = AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE; // PDU ID
415     connection->cmd_operands[pos++] = 0;
416     // Parameter Length
417     connection->cmd_operands_length = 8;
418     big_endian_store_16(connection->cmd_operands, pos, 1);
419     pos += 2;
420     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
421     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
422     return ERROR_CODE_SUCCESS;
423 }
424 
425 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
426     uint8_t operands[20];
427     uint8_t opcode;
428     int     pos = 3;
429     // uint8_t transport_header = packet[0];
430     // uint8_t transaction_label = transport_header >> 4;
431     // uint8_t packet_type = (transport_header & 0x0F) >> 2;
432     // uint8_t frame_type = (transport_header & 0x03) >> 1;
433     // uint8_t ipid = transport_header & 0x01;
434     // uint8_t byte_value = packet[2];
435     // uint16_t pid = (byte_value << 8) | packet[2];
436 
437     avrcp_command_type_t ctype = (avrcp_command_type_t) packet[pos++];
438     uint8_t byte_value = packet[pos++];
439     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (byte_value >> 3);
440     avrcp_subunit_type_t subunit_id = (avrcp_subunit_type_t)   (byte_value & 0x07);
441     opcode = packet[pos++];
442 
443     // printf("    Transport header 0x%02x (transaction_label %d, packet_type %d, frame_type %d, ipid %d), pid 0x%4x\n",
444     //     transport_header, transaction_label, packet_type, frame_type, ipid, pid);
445     // // printf_hexdump(packet+pos, size-pos);
446 
447     uint8_t pdu_id;
448     uint16_t param_length;
449     switch (avrcp_cmd_opcode(packet,size)){
450         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
451             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
452             connection->state = AVCTP_CONNECTION_OPENED;
453             // operands:
454             memcpy(operands, packet+pos, 5);
455             uint8_t unit_type = operands[1] >> 3;
456             uint8_t max_subunit_ID = operands[1] & 0x07;
457             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);
458             break;
459         }
460         case AVRCP_CMD_OPCODE_UNIT_INFO:{
461             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE) return;
462             connection->state = AVCTP_CONNECTION_OPENED;
463             // operands:
464             memcpy(operands, packet+pos, 5);
465             uint8_t unit_type = operands[1] >> 3;
466             uint8_t unit = operands[1] & 0x07;
467             uint32_t company_id = operands[2] << 16 | operands[3] << 8 | operands[4];
468             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,
469                 ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id);
470             break;
471         }
472         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
473             if (size - pos < 7) {
474                 log_error("avrcp: wrong packet size");
475                 return;
476             };
477             // operands:
478             memcpy(operands, packet+pos, 7);
479             pos += 7;
480             // uint32_t company_id = operands[0] << 16 | operands[1] << 8 | operands[2];
481             pdu_id = operands[3];
482 
483             if (connection->state != AVCTP_W2_RECEIVE_RESPONSE && pdu_id != AVRCP_PDU_ID_REGISTER_NOTIFICATION){
484                 log_info("AVRCP_CMD_OPCODE_VENDOR_DEPENDENT state %d", connection->state);
485                 return;
486             }
487             connection->state = AVCTP_CONNECTION_OPENED;
488 
489 
490             // uint8_t unit_type = operands[4] >> 3;
491             // uint8_t unit = operands[4] & 0x07;
492             param_length = big_endian_read_16(operands, 5);
493 
494             // printf("    VENDOR DEPENDENT 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%06x\n",
495             //     ctype, subunit_type, subunit_id, opcode, unit_type, unit, company_id );
496 
497             // if (ctype == AVRCP_CTYPE_RESPONSE_INTERIM) return;
498             log_info("        VENDOR DEPENDENT response: pdu id 0x%02x, param_length %d, status %s", pdu_id, param_length, avrcp_ctype2str(ctype));
499             switch (pdu_id){
500                 case AVRCP_PDU_ID_GetCurrentPlayerApplicationSettingValue:{
501                     uint8_t num_attributes = packet[pos++];
502                     int i;
503                     avrcp_repeat_mode_t  repeat_mode =  AVRCP_REPEAT_MODE_INVALID;
504                     avrcp_shuffle_mode_t shuffle_mode = AVRCP_SHUFFLE_MODE_INVALID;
505                     for (i = 0; i < num_attributes; i++){
506                         uint8_t attribute_id    = packet[pos++];
507                         uint8_t value = packet[pos++];
508                         switch (attribute_id){
509                             case 0x02:
510                                 repeat_mode = (avrcp_repeat_mode_t) value;
511                                 break;
512                             case 0x03:
513                                 shuffle_mode = (avrcp_shuffle_mode_t) value;
514                                 break;
515                             default:
516                                 break;
517                         }
518                     }
519                     avrcp_emit_repeat_and_shuffle_mode(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, repeat_mode, shuffle_mode);
520                     break;
521                 }
522                 case AVRCP_PDU_ID_SetPlayerApplicationSettingValue:{
523                     uint8_t event[6];
524                     int offset = 0;
525                     event[offset++] = HCI_EVENT_AVRCP_META;
526                     event[offset++] = sizeof(event) - 2;
527                     event[offset++] = AVRCP_SUBEVENT_PLAYER_APPLICATION_VALUE_RESPONSE;
528                     little_endian_store_16(event, offset, connection->avrcp_cid);
529                     offset += 2;
530                     event[offset++] = ctype;
531                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
532                     break;
533                 }
534                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME:{
535                     uint8_t event[7];
536                     int offset = 0;
537                     event[offset++] = HCI_EVENT_AVRCP_META;
538                     event[offset++] = sizeof(event) - 2;
539                     event[offset++] = AVRCP_SUBEVENT_SET_ABSOLUTE_VOLUME_RESPONSE;
540                     little_endian_store_16(event, offset, connection->avrcp_cid);
541                     offset += 2;
542                     event[offset++] = ctype;
543                     event[offset++] = packet[pos++];
544                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
545                     break;
546                 }
547                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
548                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos++];
549                     uint8_t capability_count = packet[pos++];
550                     int i;
551                     switch (capability_id){
552                         case AVRCP_CAPABILITY_ID_COMPANY:
553                             // log_info("Supported companies %d: ", capability_count);
554                             for (i = 0; i < capability_count; i++){
555                                 uint32_t company_id = big_endian_read_24(packet, pos);
556                                 pos += 3;
557                                 log_info("  0x%06" PRIx32 ", ", company_id);
558                             }
559                             break;
560                         case AVRCP_CAPABILITY_ID_EVENT:
561                             // log_info("Supported events %d: ", capability_count);
562                             for (i = 0; i < capability_count; i++){
563                                 uint8_t event_id = packet[pos++];
564                                 log_info("  0x%02x %s", event_id, avrcp_event2str(event_id));
565                             }
566                             break;
567                     }
568                     break;
569                 }
570                 case AVRCP_PDU_ID_GET_PLAY_STATUS:{
571                     uint32_t song_length = big_endian_read_32(packet, pos);
572                     pos += 4;
573                     uint32_t song_position = big_endian_read_32(packet, pos);
574                     pos += 4;
575                     uint8_t play_status = packet[pos];
576                     // log_info("        GET_PLAY_STATUS length 0x%04X, position 0x%04X, status %s", song_length, song_position, avrcp_play_status2str(play_status));
577 
578                     uint8_t event[15];
579                     int offset = 0;
580                     event[offset++] = HCI_EVENT_AVRCP_META;
581                     event[offset++] = sizeof(event) - 2;
582                     event[offset++] = AVRCP_SUBEVENT_PLAY_STATUS;
583                     little_endian_store_16(event, offset, connection->avrcp_cid);
584                     offset += 2;
585                     event[offset++] = ctype;
586                     little_endian_store_32(event, offset, song_length);
587                     offset += 4;
588                     little_endian_store_32(event, offset, song_position);
589                     offset += 4;
590                     event[offset++] = play_status;
591                     (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
592                     break;
593                 }
594                 case AVRCP_PDU_ID_REGISTER_NOTIFICATION:{
595                     avrcp_notification_event_id_t  event_id = (avrcp_notification_event_id_t) packet[pos++];
596                     uint16_t event_mask = (1 << event_id);
597                     uint16_t reset_event_mask = ~event_mask;
598                     switch (ctype){
599                         case AVRCP_CTYPE_RESPONSE_INTERIM:
600                             // register as enabled
601                             connection->notifications_enabled |= event_mask;
602                             // printf("INTERIM notifications_enabled 0x%2x, notifications_to_register 0x%2x\n", connection->notifications_enabled,  connection->notifications_to_register);
603                             break;
604                         case AVRCP_CTYPE_RESPONSE_CHANGED_STABLE:
605                             // received change, event is considered deregistered
606                             // we are re-enabling it automatically, if it is not
607                             // explicitly disabled
608                             connection->notifications_enabled &= reset_event_mask;
609                             if (! (connection->notifications_to_deregister & event_mask)){
610                                 avrcp_register_notification(connection, event_id);
611                                 // printf("CHANGED_STABLE notifications_enabled 0x%2x, notifications_to_register 0x%2x\n", connection->notifications_enabled,  connection->notifications_to_register);
612                             } else {
613                                 connection->notifications_to_deregister &= reset_event_mask;
614                             }
615                             break;
616                         default:
617                             connection->notifications_to_register &= reset_event_mask;
618                             connection->notifications_enabled &= reset_event_mask;
619                             connection->notifications_to_deregister &= reset_event_mask;
620                             break;
621                     }
622 
623                     switch (event_id){
624                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:{
625                             uint8_t event[7];
626                             int offset = 0;
627                             event[offset++] = HCI_EVENT_AVRCP_META;
628                             event[offset++] = sizeof(event) - 2;
629                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_PLAYBACK_STATUS_CHANGED;
630                             little_endian_store_16(event, offset, connection->avrcp_cid);
631                             offset += 2;
632                             event[offset++] = ctype;
633                             event[offset++] = packet[pos];
634                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
635                             break;
636                         }
637                         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:{
638                             uint8_t event[6];
639                             int offset = 0;
640                             event[offset++] = HCI_EVENT_AVRCP_META;
641                             event[offset++] = sizeof(event) - 2;
642                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_TRACK_CHANGED;
643                             little_endian_store_16(event, offset, connection->avrcp_cid);
644                             offset += 2;
645                             event[offset++] = ctype;
646                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
647                             break;
648                         }
649                         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:{
650                             uint8_t event[6];
651                             int offset = 0;
652                             event[offset++] = HCI_EVENT_AVRCP_META;
653                             event[offset++] = sizeof(event) - 2;
654                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_NOW_PLAYING_CONTENT_CHANGED;
655                             little_endian_store_16(event, offset, connection->avrcp_cid);
656                             offset += 2;
657                             event[offset++] = ctype;
658                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
659                             break;
660                         }
661                         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:{
662                             uint8_t event[6];
663                             int offset = 0;
664                             event[offset++] = HCI_EVENT_AVRCP_META;
665                             event[offset++] = sizeof(event) - 2;
666                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_AVAILABLE_PLAYERS_CHANGED;
667                             little_endian_store_16(event, offset, connection->avrcp_cid);
668                             offset += 2;
669                             event[offset++] = ctype;
670                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
671                             break;
672                         }
673                         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:{
674                             uint8_t event[7];
675                             int offset = 0;
676                             event[offset++] = HCI_EVENT_AVRCP_META;
677                             event[offset++] = sizeof(event) - 2;
678                             event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
679                             little_endian_store_16(event, offset, connection->avrcp_cid);
680                             offset += 2;
681                             event[offset++] = ctype;
682                             event[offset++] = packet[pos++] & 0x7F;
683                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
684                             break;
685                         }
686                         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:{
687                             uint8_t event[7];
688                             int offset = 0;
689                             event[offset++] = HCI_EVENT_AVRCP_META;
690                             event[offset++] = sizeof(event) - 2;
691                             event[offset++] = AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED;
692                             little_endian_store_16(event, offset, connection->avrcp_cid);
693                             offset += 2;
694                             event[offset++] = ctype;
695                             event[offset++] = packet[pos++] & 0x7F;
696                             (*avrcp_controller_context.avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
697                             break;
698                         }
699 
700                         // case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:{
701                         //     uint8_t num_PlayerApplicationSettingAttributes = packet[pos++];
702                         //     int i;
703                         //     for (i = 0; i < num_PlayerApplicationSettingAttributes; i++){
704                         //         uint8_t PlayerApplicationSetting_AttributeID = packet[pos++];
705                         //         uint8_t PlayerApplicationSettingValueID = packet[pos++];
706                         //     }
707                         //     break;
708                         // }
709                         // case AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED:
710                         //     uint16_t player_id = big_endian_read_16(packet, pos);
711                         //     pos += 2;
712                         //     uint16_t uid_counter = big_endian_read_16(packet, pos);
713                         //     pos += 2;
714                         //     break;
715                         // case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:
716                         //     uint16_t uid_counter = big_endian_read_16(packet, pos);
717                         //     pos += 2;
718                         //     break;
719                         default:
720                             log_info("avrcp: not implemented");
721                             break;
722                     }
723                     if (connection->notifications_to_register != 0){
724                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
725                     }
726                     break;
727                 }
728 
729                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
730                     avrcp_packet_type_t packet_type = operands[4] & 0x03;
731                     switch (packet_type){
732                         case AVRCP_START_PACKET:
733                         case AVRCP_SINGLE_PACKET:
734                             avrcp_parser_reset(connection);
735                             connection->list_size = param_length;
736                             connection->num_attributes = packet[pos++];
737 
738                             // printf("AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES num_attributes %d, total size %d, packet type 0x%02x \n", connection->num_attributes, connection->list_size, operands[4] & 0x03);
739                             avrcp_source_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
740 
741                             if (packet_type == AVRCP_START_PACKET){
742                                 avrcp_controller_request_continue_response(connection);
743                             }
744                             break;
745                         case AVRCP_CONTINUE_PACKET:
746                         case AVRCP_END_PACKET:
747                             connection->num_received_fragments++;
748                             if (connection->num_received_fragments < connection->max_num_fragments){
749                                 avrcp_source_parse_and_emit_element_attrs(packet+pos, size-pos, connection, ctype);
750                                 if (packet_type == AVRCP_CONTINUE_PACKET){
751                                     avrcp_controller_request_continue_response(connection);
752                                 }
753                             } else {
754                                 avrcp_controller_request_abort_continuation(connection);
755                                 avrcp_controller_emit_now_playing_info_event_done(avrcp_controller_context.avrcp_callback, connection->avrcp_cid, ctype, 1);
756                                 avrcp_parser_reset(connection);
757                             }
758                             break;
759                     }
760                 }
761                 default:
762                     break;
763             }
764             break;
765         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
766             // 0x80 | connection->cmd_operands[0]
767             uint8_t operation_id = packet[pos++];
768             switch (connection->state){
769                 case AVCTP_W2_RECEIVE_PRESS_RESPONSE:
770                     if (connection->continuous_fast_forward_cmd){
771                         connection->state = AVCTP_W4_STOP;
772                     } else {
773                         connection->state = AVCTP_W2_SEND_RELEASE_COMMAND;
774                     }
775                     break;
776                 case AVCTP_W2_RECEIVE_RESPONSE:
777                     connection->state = AVCTP_CONNECTION_OPENED;
778                     break;
779                 default:
780                     // check for notifications? move state transition down
781                     // log_info("AVRCP_CMD_OPCODE_PASS_THROUGH state %d\n", connection->state);
782                     break;
783             }
784             if (connection->state == AVCTP_W4_STOP){
785                 avrcp_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_START, connection->avrcp_cid, ctype, operation_id);
786             }
787             if (connection->state == AVCTP_CONNECTION_OPENED) {
788                 // RELEASE response
789                 operation_id = operation_id & 0x7F;
790                 avrcp_emit_operation_status(avrcp_controller_context.avrcp_callback, AVRCP_SUBEVENT_OPERATION_COMPLETE, connection->avrcp_cid, ctype, operation_id);
791             }
792             if (connection->state == AVCTP_W2_SEND_RELEASE_COMMAND){
793                 // PRESS response
794                 request_pass_through_release_control_cmd(connection);
795             }
796             break;
797         }
798         default:
799             break;
800     }
801 }
802 
803 static void avrcp_controller_handle_can_send_now(avrcp_connection_t * connection){
804     int i;
805     switch (connection->state){
806         case AVCTP_W2_SEND_PRESS_COMMAND:
807             connection->state = AVCTP_W2_RECEIVE_PRESS_RESPONSE;
808             avrcp_send_cmd(connection->l2cap_signaling_cid, connection);
809             break;
810         case AVCTP_W2_SEND_COMMAND:
811         case AVCTP_W2_SEND_RELEASE_COMMAND:
812             connection->state = AVCTP_W2_RECEIVE_RESPONSE;
813             avrcp_send_cmd(connection->l2cap_signaling_cid, connection);
814             break;
815         case AVCTP_CONNECTION_OPENED:
816             if (connection->notifications_to_register != 0){
817                 for (i = 1; i <= AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED; i++){
818                     if (connection->notifications_to_register & (1<<i)){
819                         connection->notifications_to_register &= ~ (1 << i);
820                         avrcp_prepare_notification(connection, (avrcp_notification_event_id_t) i);
821                         connection->state = AVCTP_W2_RECEIVE_RESPONSE;
822                         avrcp_send_cmd(connection->l2cap_signaling_cid, connection);
823                         return;
824                     }
825                 }
826             }
827             return;
828         default:
829             return;
830     }
831 }
832 
833 static void avrcp_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
834     avrcp_connection_t * connection;
835 
836     switch (packet_type) {
837         case L2CAP_DATA_PACKET:
838             connection = get_avrcp_connection_for_l2cap_signaling_cid(channel, &avrcp_controller_context);
839             if (!connection) break;
840             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
841             break;
842         case HCI_EVENT_PACKET:
843             switch (hci_event_packet_get_type(packet)){
844                 case L2CAP_EVENT_CAN_SEND_NOW:
845                     connection = get_avrcp_connection_for_l2cap_signaling_cid(channel, &avrcp_controller_context);
846                     if (!connection) break;
847                     avrcp_controller_handle_can_send_now(connection);
848                     break;
849             default:
850                 avrcp_packet_handler(packet_type, channel, packet, size, &avrcp_controller_context);
851                 break;
852         }
853         default:
854             break;
855     }
856 }
857 
858 void avrcp_controller_init(void){
859     avrcp_controller_context.role = AVRCP_CONTROLLER;
860     avrcp_controller_context.connections = NULL;
861     avrcp_controller_context.packet_handler = avrcp_controller_packet_handler;
862     l2cap_register_service(&avrcp_controller_packet_handler, BLUETOOTH_PROTOCOL_AVCTP, 0xffff, LEVEL_0);
863 }
864 
865 void avrcp_controller_register_packet_handler(btstack_packet_handler_t callback){
866     if (callback == NULL){
867         log_error("avrcp_register_packet_handler called with NULL callback");
868         return;
869     }
870     avrcp_controller_context.avrcp_callback = callback;
871 }
872 
873 uint8_t avrcp_controller_connect(bd_addr_t bd_addr, uint16_t * avrcp_cid){
874     return avrcp_connect(bd_addr, &avrcp_controller_context, avrcp_cid);
875 }
876 
877 uint8_t avrcp_controller_unit_info(uint16_t avrcp_cid){
878     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
879     if (!connection){
880         log_error("avrcp_unit_info: could not find a connection.");
881         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
882     }
883     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
884     connection->state = AVCTP_W2_SEND_COMMAND;
885 
886     connection->transaction_label++;
887     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
888     connection->command_type = AVRCP_CTYPE_STATUS;
889     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
890     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
891     memset(connection->cmd_operands, 0xFF, connection->cmd_operands_length);
892     connection->cmd_operands_length = 5;
893     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
894     return ERROR_CODE_SUCCESS;
895 }
896 
897 uint8_t avrcp_controller_subunit_info(uint16_t avrcp_cid){
898     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
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_SUBUNIT_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[0] = 7; // page: 0, extention_code: 7
913     connection->cmd_operands_length = 5;
914     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
915     return ERROR_CODE_SUCCESS;
916 }
917 
918 static uint8_t avrcp_controller_get_capabilities(uint16_t avrcp_cid, uint8_t capability_id){
919     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
920     if (!connection){
921         log_error("avrcp_get_capabilities: could not find a connection.");
922         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
923     }
924     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
925     connection->state = AVCTP_W2_SEND_COMMAND;
926 
927     connection->transaction_label++;
928     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
929     connection->command_type = AVRCP_CTYPE_STATUS;
930     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
931     connection->subunit_id = AVRCP_SUBUNIT_ID;
932     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
933     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_CAPABILITIES; // PDU ID
934     connection->cmd_operands[4] = 0;
935     big_endian_store_16(connection->cmd_operands, 5, 1); // parameter length
936     connection->cmd_operands[7] = capability_id;                  // capability ID
937     connection->cmd_operands_length = 8;
938     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
939     return ERROR_CODE_SUCCESS;
940 }
941 
942 uint8_t avrcp_controller_get_supported_company_ids(uint16_t avrcp_cid){
943     return avrcp_controller_get_capabilities(avrcp_cid, AVRCP_CAPABILITY_ID_COMPANY);
944 }
945 
946 uint8_t avrcp_controller_get_supported_events(uint16_t avrcp_cid){
947     return avrcp_controller_get_capabilities(avrcp_cid, AVRCP_CAPABILITY_ID_EVENT);
948 }
949 
950 
951 uint8_t avrcp_controller_play(uint16_t avrcp_cid){
952     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PLAY, 0);
953 }
954 
955 uint8_t avrcp_controller_stop(uint16_t avrcp_cid){
956     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_STOP, 0);
957 }
958 
959 uint8_t avrcp_controller_pause(uint16_t avrcp_cid){
960     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_PAUSE, 0);
961 }
962 
963 uint8_t avrcp_controller_forward(uint16_t avrcp_cid){
964     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FORWARD, 0);
965 }
966 
967 uint8_t avrcp_controller_backward(uint16_t avrcp_cid){
968     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_BACKWARD, 0);
969 }
970 
971 uint8_t avrcp_controller_start_rewind(uint16_t avrcp_cid){
972     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
973 }
974 
975 uint8_t avrcp_controller_volume_up(uint16_t avrcp_cid){
976     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_UP, 0);
977 }
978 
979 uint8_t avrcp_controller_volume_down(uint16_t avrcp_cid){
980     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_VOLUME_DOWN, 0);
981 }
982 
983 uint8_t avrcp_controller_mute(uint16_t avrcp_cid){
984     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_MUTE, 0);
985 }
986 
987 uint8_t avrcp_controller_skip(uint16_t avrcp_cid){
988     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_SKIP, 0);
989 }
990 
991 uint8_t avrcp_controller_stop_rewind(uint16_t avrcp_cid){
992     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
993     if (!connection){
994         log_error("avrcp_stop_rewind: could not find a connection.");
995         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
996     }
997     if (connection->state != AVCTP_W4_STOP) return ERROR_CODE_COMMAND_DISALLOWED;
998     return request_pass_through_release_control_cmd(connection);
999 }
1000 
1001 uint8_t avrcp_controller_start_fast_forward(uint16_t avrcp_cid){
1002     return request_continuous_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1003 }
1004 
1005 uint8_t avrcp_controller_fast_forward(uint16_t avrcp_cid){
1006     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_FAST_FORWARD, 0);
1007 }
1008 
1009 uint8_t avrcp_controller_rewind(uint16_t avrcp_cid){
1010     return request_single_pass_through_press_control_cmd(avrcp_cid, AVRCP_OPERATION_ID_REWIND, 0);
1011 }
1012 
1013 
1014 uint8_t avrcp_controller_stop_fast_forward(uint16_t avrcp_cid){
1015     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1016     if (!connection){
1017         log_error("avrcp_stop_fast_forward: could not find a connection.");
1018         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1019     }
1020     if (connection->state != AVCTP_W4_STOP) return ERROR_CODE_COMMAND_DISALLOWED;
1021     return request_pass_through_release_control_cmd(connection);
1022 }
1023 
1024 uint8_t avrcp_controller_get_play_status(uint16_t avrcp_cid){
1025     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1026     if (!connection){
1027         log_error("avrcp_get_play_status: 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     connection->transaction_label++;
1033     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1034     connection->command_type = AVRCP_CTYPE_STATUS;
1035     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1036     connection->subunit_id = AVRCP_SUBUNIT_ID;
1037     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1038     connection->cmd_operands[3] = AVRCP_PDU_ID_GET_PLAY_STATUS;
1039     connection->cmd_operands[4] = 0;                     // reserved(upper 6) | packet_type -> 0
1040     big_endian_store_16(connection->cmd_operands, 5, 0); // parameter length
1041     connection->cmd_operands_length = 7;
1042     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1043     return ERROR_CODE_SUCCESS;
1044 }
1045 
1046 uint8_t avrcp_controller_enable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1047     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1048     if (!connection){
1049         log_error("avrcp_get_play_status: could not find a connection.");
1050         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1051     }
1052     avrcp_register_notification(connection, event_id);
1053     return ERROR_CODE_SUCCESS;
1054 }
1055 
1056 uint8_t avrcp_controller_disable_notification(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
1057     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1058     if (!connection){
1059         log_error("avrcp_get_play_status: could not find a connection.");
1060         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1061     }
1062     connection->notifications_to_deregister |= (1 << event_id);
1063     return ERROR_CODE_SUCCESS;
1064 }
1065 
1066 uint8_t avrcp_controller_set_addressed_player(uint16_t avrcp_cid, uint16_t addressed_player_id){
1067     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1068     if (!connection){
1069         log_error("avrcp_get_capabilities: could not find a connection.");
1070         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1071     }
1072     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1073     connection->state = AVCTP_W2_SEND_COMMAND;
1074 
1075     connection->transaction_label++;
1076     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1077     connection->command_type = AVRCP_CTYPE_CONTROL;
1078     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1079     connection->subunit_id = AVRCP_SUBUNIT_ID;
1080     int pos = 0;
1081     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1082     pos += 3;
1083     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ADDRESSED_PLAYER; // PDU ID
1084     connection->cmd_operands[pos++] = 0;
1085 
1086     // Parameter Length
1087     big_endian_store_16(connection->cmd_operands, pos, 2);
1088     pos += 2;
1089 
1090     big_endian_store_16(connection->cmd_operands, pos, addressed_player_id);
1091     pos += 2;
1092 
1093     connection->cmd_operands_length = pos;
1094     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1095     return ERROR_CODE_SUCCESS;
1096 }
1097 
1098 uint8_t avrcp_controller_get_now_playing_info(uint16_t avrcp_cid){
1099     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1100     if (!connection){
1101         log_error("avrcp_get_capabilities: could not find a connection.");
1102         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1103     }
1104     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1105     connection->state = AVCTP_W2_SEND_COMMAND;
1106 
1107     connection->transaction_label++;
1108     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1109     connection->command_type = AVRCP_CTYPE_STATUS;
1110     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1111     connection->subunit_id = AVRCP_SUBUNIT_ID;
1112     int pos = 0;
1113     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1114     pos += 3;
1115     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES; // PDU ID
1116     connection->cmd_operands[pos++] = 0;
1117 
1118     // Parameter Length
1119     big_endian_store_16(connection->cmd_operands, pos, 9);
1120     pos += 2;
1121 
1122     // write 8 bytes value
1123     memset(connection->cmd_operands + pos, 0, 8); // identifier: PLAYING
1124     pos += 8;
1125 
1126     connection->cmd_operands[pos++] = 0; // attribute count, if 0 get all attributes
1127     // every attribute is 4 bytes long
1128 
1129     connection->cmd_operands_length = pos;
1130     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1131     return ERROR_CODE_SUCCESS;
1132 }
1133 
1134 uint8_t avrcp_controller_set_absolute_volume(uint16_t avrcp_cid, uint8_t volume){
1135      avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1136     if (!connection){
1137         log_error("avrcp_get_capabilities: could not find a connection.");
1138         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1139     }
1140     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1141     connection->state = AVCTP_W2_SEND_COMMAND;
1142 
1143     connection->transaction_label++;
1144     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1145     connection->command_type = AVRCP_CTYPE_CONTROL;
1146     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1147     connection->subunit_id = AVRCP_SUBUNIT_ID;
1148     int pos = 0;
1149     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1150     pos += 3;
1151     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME; // PDU ID
1152     connection->cmd_operands[pos++] = 0;
1153 
1154     // Parameter Length
1155     big_endian_store_16(connection->cmd_operands, pos, 1);
1156     pos += 2;
1157     connection->cmd_operands[pos++] = volume;
1158 
1159     connection->cmd_operands_length = pos;
1160     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1161     return ERROR_CODE_SUCCESS;
1162 }
1163 
1164 uint8_t avrcp_controller_query_shuffle_and_repeat_modes(uint16_t avrcp_cid){
1165     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1166     if (!connection){
1167         log_error("avrcp_get_capabilities: could not find a connection.");
1168         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1169     }
1170     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1171     connection->state = AVCTP_W2_SEND_COMMAND;
1172 
1173     connection->transaction_label++;
1174     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1175     connection->command_type = AVRCP_CTYPE_STATUS;
1176     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1177     connection->subunit_id = AVRCP_SUBUNIT_ID;
1178     big_endian_store_24(connection->cmd_operands, 0, BT_SIG_COMPANY_ID);
1179     connection->cmd_operands[3] = AVRCP_PDU_ID_GetCurrentPlayerApplicationSettingValue; // PDU ID
1180     connection->cmd_operands[4] = 0;
1181     big_endian_store_16(connection->cmd_operands, 5, 5); // parameter length
1182     connection->cmd_operands[7] = 4;                     // NumPlayerApplicationSettingAttributeID
1183     // PlayerApplicationSettingAttributeID1 AVRCP Spec, Appendix F, 133
1184     connection->cmd_operands[8]  = 0x01;    // equalizer  (1-OFF, 2-ON)
1185     connection->cmd_operands[9]  = 0x02;    // repeat     (1-off, 2-single track, 3-all tracks, 4-group repeat)
1186     connection->cmd_operands[10] = 0x03;    // shuffle    (1-off, 2-all tracks, 3-group shuffle)
1187     connection->cmd_operands[11] = 0x04;    // scan       (1-off, 2-all tracks, 3-group scan)
1188     connection->cmd_operands_length = 12;
1189     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1190     return ERROR_CODE_SUCCESS;
1191 }
1192 
1193 static uint8_t avrcp_controller_set_current_player_application_setting_value(uint16_t avrcp_cid, uint8_t attr_id, uint8_t attr_value){
1194     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1195     if (!connection){
1196         log_error("avrcp_get_capabilities: could not find a connection.");
1197         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1198     }
1199     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1200     connection->state = AVCTP_W2_SEND_COMMAND;
1201 
1202     connection->transaction_label++;
1203     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1204     connection->command_type = AVRCP_CTYPE_CONTROL;
1205     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1206     connection->subunit_id = AVRCP_SUBUNIT_ID;
1207     int pos = 0;
1208     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1209     pos += 3;
1210     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SetPlayerApplicationSettingValue; // PDU ID
1211     connection->cmd_operands[pos++] = 0;
1212     // Parameter Length
1213     big_endian_store_16(connection->cmd_operands, pos, 3);
1214     pos += 2;
1215     connection->cmd_operands[pos++] = 2;
1216     connection->cmd_operands_length = pos;
1217     connection->cmd_operands[pos++]  = attr_id;
1218     connection->cmd_operands[pos++]  = attr_value;
1219     connection->cmd_operands_length = pos;
1220     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1221     return ERROR_CODE_SUCCESS;
1222 }
1223 
1224 uint8_t avrcp_controller_set_shuffle_mode(uint16_t avrcp_cid, avrcp_shuffle_mode_t mode){
1225     if (mode < AVRCP_SHUFFLE_MODE_OFF || mode > AVRCP_SHUFFLE_MODE_GROUP) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1226     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x03, mode);
1227 }
1228 
1229 uint8_t avrcp_controller_set_repeat_mode(uint16_t avrcp_cid, avrcp_repeat_mode_t mode){
1230     if (mode < AVRCP_REPEAT_MODE_OFF || mode > AVRCP_REPEAT_MODE_GROUP) return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
1231     return avrcp_controller_set_current_player_application_setting_value(avrcp_cid, 0x02, mode);
1232 }
1233 
1234 uint8_t avrcp_controller_disconnect(uint16_t avrcp_cid){
1235     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1236     if (!connection){
1237         log_error("avrcp_get_capabilities: could not find a connection.");
1238         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1239     }
1240     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1241     if (connection->browsing_connection){
1242         if (connection->browsing_connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1243         l2cap_disconnect(connection->browsing_connection->l2cap_browsing_cid, 0);
1244     }
1245     l2cap_disconnect(connection->l2cap_signaling_cid, 0);
1246     return ERROR_CODE_SUCCESS;
1247 }
1248 
1249 uint8_t avrcp_controller_play_item_for_scope(uint16_t avrcp_cid, uint8_t * uid, uint16_t uid_counter, avrcp_browsing_scope_t scope){
1250     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1251     if (!connection){
1252         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1253         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1254     }
1255     if (connection->state != AVCTP_CONNECTION_OPENED){
1256         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1257         return ERROR_CODE_COMMAND_DISALLOWED;
1258     }
1259     connection->state = AVCTP_W2_SEND_COMMAND;
1260 
1261     connection->transaction_label++;
1262     connection->command_type = AVRCP_CTYPE_CONTROL;
1263     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1264     connection->subunit_id = AVRCP_SUBUNIT_ID;
1265     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1266     int pos = 0;
1267     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1268     pos += 3;
1269     connection->cmd_operands[pos++] = AVRCP_PDU_ID_PLAY_ITEM; // PDU ID
1270     // reserved
1271     connection->cmd_operands[pos++] = 0;
1272     // Parameter Length
1273     big_endian_store_16(connection->cmd_operands, pos, 11);
1274     pos += 2;
1275     connection->cmd_operands[pos++]  = scope;
1276     memset(&connection->cmd_operands[pos], 0, 8);
1277     if (uid){
1278         memcpy(&connection->cmd_operands[pos], uid, 8);
1279     }
1280     pos += 8;
1281     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1282     pos += 2;
1283     connection->cmd_operands_length = pos;
1284 
1285     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1286     return ERROR_CODE_SUCCESS;
1287 }
1288 
1289 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){
1290     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1291     if (!connection){
1292         log_error("Could not find a connection with cid 0%02x.", avrcp_cid);
1293         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1294     }
1295     if (connection->state != AVCTP_CONNECTION_OPENED){
1296         log_error("Connection in wrong state, expected %d, received %d", AVCTP_CONNECTION_OPENED, connection->state);
1297         return ERROR_CODE_COMMAND_DISALLOWED;
1298     }
1299     connection->state = AVCTP_W2_SEND_COMMAND;
1300 
1301     connection->transaction_label++;
1302     connection->command_type = AVRCP_CTYPE_CONTROL;
1303     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
1304     connection->subunit_id = AVRCP_SUBUNIT_ID;
1305     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1306     int pos = 0;
1307     big_endian_store_24(connection->cmd_operands, pos, BT_SIG_COMPANY_ID);
1308     pos += 3;
1309     connection->cmd_operands[pos++] = AVRCP_PDU_ID_ADD_TO_NOW_PLAYING; // PDU ID
1310     // reserved
1311     connection->cmd_operands[pos++] = 0;
1312     // Parameter Length
1313     big_endian_store_16(connection->cmd_operands, pos, 11);
1314     pos += 2;
1315     connection->cmd_operands[pos++]  = scope;
1316     memset(&connection->cmd_operands[pos], 0, 8);
1317     if (uid){
1318         memcpy(&connection->cmd_operands[pos], uid, 8);
1319     }
1320     pos += 8;
1321     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
1322     pos += 2;
1323     connection->cmd_operands_length = pos;
1324 
1325     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1326     return ERROR_CODE_SUCCESS;
1327 }
1328 
1329 uint8_t avrcp_controller_set_max_num_fragments(uint16_t avrcp_cid, uint8_t max_num_fragments){
1330     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_controller_context);
1331     if (!connection){
1332         log_error("avrcp_controller_play_item: could not find a connection.");
1333         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1334     }
1335     connection->max_num_fragments = max_num_fragments;
1336     return ERROR_CODE_SUCCESS;
1337 }
1338