xref: /btstack/src/classic/avrcp_target.c (revision 398a95ec8e0d408db97ed8e80c67c74e30698a03)
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_target.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 
49 #define AVRCP_ATTR_HEADER_LEN  8
50 
51 static const uint8_t AVRCP_NOTIFICATION_TRACK_SELECTED[] = {0,0,0,0,0,0,0,0};
52 static const uint8_t AVRCP_NOTIFICATION_TRACK_NOT_SELECTED[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
53 
54 avrcp_context_t avrcp_target_context;
55 
56 void avrcp_target_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){
57     avrcp_create_sdp_record(0, service, service_record_handle, browsing, supported_features, service_name, service_provider_name);
58 }
59 
60 static void avrcp_target_emit_operation(btstack_packet_handler_t callback, uint16_t avrcp_cid, avrcp_operation_id_t operation_id, uint8_t operands_length, uint8_t operand){
61     if (!callback) return;
62     uint8_t event[8];
63     int pos = 0;
64     event[pos++] = HCI_EVENT_AVRCP_META;
65     event[pos++] = sizeof(event) - 2;
66     event[pos++] = AVRCP_SUBEVENT_OPERATION;
67     little_endian_store_16(event, pos, avrcp_cid);
68     pos += 2;
69     event[pos++] = operation_id;
70     event[pos++] = operands_length;
71     event[pos++] = operand;
72     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
73 }
74 
75 static void avrcp_target_emit_respond_vendor_dependent_query(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t subevent_id){
76     if (!callback) return;
77     uint8_t event[5];
78     int pos = 0;
79     event[pos++] = HCI_EVENT_AVRCP_META;
80     event[pos++] = sizeof(event) - 2;
81     event[pos++] = subevent_id;
82     little_endian_store_16(event, pos, avrcp_cid);
83     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
84 }
85 
86 static uint16_t avrcp_target_pack_single_element_attribute_number(uint8_t * packet, uint16_t pos, avrcp_media_attribute_id_t attr_id, uint32_t value){
87     if ((attr_id < 1) || (attr_id > AVRCP_MEDIA_ATTR_COUNT)) return 0;
88     uint16_t attr_value_length = sprintf((char *)(packet+pos+8), "%0" PRIu32, value);
89     big_endian_store_32(packet, pos, attr_id);
90     pos += 4;
91     big_endian_store_16(packet, pos, RFC2978_CHARSET_MIB_UTF8);
92     pos += 2;
93     big_endian_store_16(packet, pos, attr_value_length);
94     pos += 2;
95     return 8 + attr_value_length;
96 }
97 
98 static uint16_t avrcp_target_pack_single_element_attribute_string(uint8_t * packet, uint16_t pos, rfc2978_charset_mib_enumid_t mib_enumid, avrcp_media_attribute_id_t attr_id, uint8_t * attr_value, uint16_t attr_value_to_copy, uint16_t attr_value_size, uint8_t header){
99     if (attr_value_size == 0) return 0;
100     if ((attr_id < 1) || (attr_id > AVRCP_MEDIA_ATTR_COUNT)) return 0;
101     if (header){
102         big_endian_store_32(packet, pos, attr_id);
103         pos += 4;
104         big_endian_store_16(packet, pos, mib_enumid);
105         pos += 2;
106         big_endian_store_16(packet, pos, attr_value_size);
107         pos += 2;
108     }
109     memcpy(packet+pos, attr_value, attr_value_to_copy);
110     pos += attr_value_size;
111     return header * 8 + attr_value_size;
112 }
113 
114 static int avrcp_target_abort_continue_response(uint16_t cid, avrcp_connection_t * connection){
115     uint16_t pos = 0;
116     l2cap_reserve_packet_buffer();
117     uint8_t * packet = l2cap_get_outgoing_buffer();
118 
119     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
120     connection->command_type    = AVRCP_CTYPE_RESPONSE_ACCEPTED;
121     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
122     connection->subunit_id      = AVRCP_SUBUNIT_ID;
123 
124     packet[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
125     // Profile IDentifier (PID)
126     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
127     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
128 
129     // command_type
130     packet[pos++] = connection->command_type;
131     // subunit_type | subunit ID
132     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
133     // opcode
134     packet[pos++] = (uint8_t)connection->command_opcode;
135 
136     // company id is 3 bytes long
137     big_endian_store_24(packet, pos, BT_SIG_COMPANY_ID);
138     pos += 3;
139 
140     packet[pos++] = AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE;
141 
142     // reserve byte for packet type
143     packet[pos++] = AVRCP_SINGLE_PACKET;
144     big_endian_store_16(packet, pos, 0);
145     pos += 2;
146     return l2cap_send_prepared(cid, pos);
147 }
148 
149 static int avrcp_target_send_now_playing_info(uint16_t cid, avrcp_connection_t * connection){
150     uint16_t pos = 0;
151     l2cap_reserve_packet_buffer();
152     uint8_t * packet = l2cap_get_outgoing_buffer();
153     uint16_t  size   = l2cap_get_remote_mtu_for_local_cid(connection->l2cap_signaling_cid);
154 
155     packet[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
156     // Profile IDentifier (PID)
157     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
158     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
159 
160     // command_type
161     packet[pos++] = connection->command_type;
162     // subunit_type | subunit ID
163     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
164     // opcode
165     packet[pos++] = (uint8_t)connection->command_opcode;
166 
167     // company id is 3 bytes long
168     big_endian_store_24(packet, pos, BT_SIG_COMPANY_ID);
169     pos += 3;
170 
171     packet[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
172 
173     // reserve byte for packet type
174     uint8_t pos_packet_type = pos;
175     pos++;
176 
177     uint16_t playing_info_buffer_len_position = pos;
178     pos += 2;
179     // printf("connection->next_attr_id %d \n", connection->next_attr_id);
180     if (connection->next_attr_id == AVRCP_MEDIA_ATTR_NONE){
181         packet[pos_packet_type] = AVRCP_SINGLE_PACKET;
182         connection->packet_type = AVRCP_SINGLE_PACKET;
183         packet[pos++] = count_set_bits_uint32(connection->now_playing_info_attr_bitmap);
184         connection->next_attr_id = AVRCP_MEDIA_ATTR_ALL;
185     }
186     // printf("updated connection->next_attr_id %d, connection->attribute_value_offset %d \n", connection->next_attr_id, connection->attribute_value_offset);
187 
188     uint8_t fragmented = 0;
189     int num_free_bytes = size - pos - 2;
190     uint8_t MAX_NUMBER_ATTR_LEN = 10;
191 
192     while (!fragmented && num_free_bytes > 0 && connection->next_attr_id <= AVRCP_MEDIA_ATTR_SONG_LENGTH_MS){
193         avrcp_media_attribute_id_t attr_id = connection->next_attr_id;
194         int attr_index = attr_id - 1;
195 
196         if (connection->now_playing_info_attr_bitmap & (1 << attr_id)){
197             int num_written_bytes = 0;
198             int num_bytes_to_write = 0;
199             switch (attr_id){
200                 case AVRCP_MEDIA_ATTR_ALL:
201                 case AVRCP_MEDIA_ATTR_NONE:
202                     break;
203                 case AVRCP_MEDIA_ATTR_TRACK:
204                     num_bytes_to_write = AVRCP_ATTR_HEADER_LEN + MAX_NUMBER_ATTR_LEN;
205                     if (num_free_bytes >= num_bytes_to_write){
206                         num_written_bytes = avrcp_target_pack_single_element_attribute_number(packet, pos, attr_id, connection->track_nr);
207                         break;
208                     }
209                     fragmented = 1;
210                     connection->attribute_value_offset = 0;
211                     break;
212                 case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
213                     num_bytes_to_write = AVRCP_ATTR_HEADER_LEN + MAX_NUMBER_ATTR_LEN;
214                     if (num_free_bytes >= num_bytes_to_write){
215                         num_written_bytes = avrcp_target_pack_single_element_attribute_number(packet, pos, attr_id, connection->total_tracks);
216                         break;
217                     }
218                     fragmented = 1;
219                     connection->attribute_value_offset = 0;
220                     break;
221                 case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
222                     num_bytes_to_write = AVRCP_ATTR_HEADER_LEN + MAX_NUMBER_ATTR_LEN;
223                     if (num_free_bytes >= num_bytes_to_write){
224                         num_written_bytes = avrcp_target_pack_single_element_attribute_number(packet, pos, attr_id, connection->song_length_ms);
225                         break;
226                     }
227                     fragmented = 1;
228                     connection->attribute_value_offset = 0;
229                     break;
230                 default:{
231                     uint8_t   header = (connection->attribute_value_offset == 0);
232                     uint8_t * attr_value =     (uint8_t *) (connection->now_playing_info[attr_index].value + connection->attribute_value_offset);
233                     uint16_t  attr_value_len = connection->now_playing_info[attr_index].len - connection->attribute_value_offset;
234 
235                     num_bytes_to_write = attr_value_len + header * AVRCP_ATTR_HEADER_LEN;
236                     if (num_bytes_to_write <= num_free_bytes){
237                         connection->attribute_value_offset = 0;
238                         num_written_bytes = num_bytes_to_write;
239                         avrcp_target_pack_single_element_attribute_string(packet, pos, RFC2978_CHARSET_MIB_UTF8, attr_id, attr_value, attr_value_len, connection->now_playing_info[attr_index].len, header);
240                         break;
241                     }
242                     fragmented = 1;
243                     num_written_bytes = num_free_bytes;
244                     attr_value_len = num_free_bytes - header * AVRCP_ATTR_HEADER_LEN;
245                     avrcp_target_pack_single_element_attribute_string(packet, pos, RFC2978_CHARSET_MIB_UTF8, attr_id, attr_value, attr_value_len, connection->now_playing_info[attr_index].len, header);
246                     connection->attribute_value_offset += attr_value_len;
247                     break;
248                 }
249             }
250             pos += num_written_bytes;
251             num_free_bytes -= num_written_bytes;
252         }
253         if (!fragmented){
254             // C++ compatible version of connection->next_attr_id++
255             connection->next_attr_id = (avrcp_media_attribute_id_t) (((int) connection->next_attr_id) + 1);
256         }
257     }
258 
259     if (fragmented){
260         switch (connection->packet_type){
261             case AVRCP_SINGLE_PACKET:
262                 connection->packet_type = AVRCP_START_PACKET;
263                 break;
264             default:
265                 connection->packet_type = AVRCP_CONTINUE_PACKET;
266                 break;
267         }
268     } else {
269         if (connection->next_attr_id >= AVRCP_MEDIA_ATTR_SONG_LENGTH_MS){ // DONE
270             if (connection->packet_type != AVRCP_SINGLE_PACKET){
271                 connection->packet_type = AVRCP_END_PACKET;
272             }
273         }
274     }
275     packet[pos_packet_type] = connection->packet_type;
276     // store attr value length
277     big_endian_store_16(packet, playing_info_buffer_len_position, pos - playing_info_buffer_len_position - 2);
278     return l2cap_send_prepared(cid, size);
279 }
280 
281 
282 
283 static int avrcp_target_send_response(uint16_t cid, avrcp_connection_t * connection){
284     int pos = 0;
285     l2cap_reserve_packet_buffer();
286     uint8_t * packet = l2cap_get_outgoing_buffer();
287 
288     // transport header
289     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
290 
291     // TODO: check for fragmentation
292     connection->packet_type = AVRCP_SINGLE_PACKET;
293 
294     packet[pos++] = (connection->transaction_label << 4) | (connection->packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
295     // Profile IDentifier (PID)
296     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
297     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
298     // command_type
299     packet[pos++] = connection->command_type;
300     // subunit_type | subunit ID
301     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
302     // opcode
303     packet[pos++] = (uint8_t)connection->command_opcode;
304     // operands
305     memcpy(packet+pos, connection->cmd_operands, connection->cmd_operands_length);
306     // printf_hexdump(packet+pos, connection->cmd_operands_length);
307 
308     pos += connection->cmd_operands_length;
309     connection->wait_to_send = 0;
310     return l2cap_send_prepared(cid, pos);
311 }
312 
313 static uint8_t avrcp_target_response_accept(avrcp_connection_t * connection, avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id, avrcp_command_opcode_t opcode, avrcp_pdu_id_t pdu_id, avrcp_status_code_t status){
314     // AVRCP_CTYPE_RESPONSE_REJECTED
315     connection->command_type = AVRCP_CTYPE_RESPONSE_ACCEPTED;
316     connection->subunit_type = subunit_type;
317     connection->subunit_id =   subunit_id;
318     connection->command_opcode = opcode;
319     // company id is 3 bytes long
320     int pos = connection->cmd_operands_length;
321     connection->cmd_operands[pos++] = pdu_id;
322     connection->cmd_operands[pos++] = 0;
323     // param length
324     big_endian_store_16(connection->cmd_operands, pos, 1);
325     pos += 2;
326     connection->cmd_operands[pos++] = status;
327     connection->cmd_operands_length = pos;
328     connection->state = AVCTP_W2_SEND_RESPONSE;
329     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
330     return ERROR_CODE_SUCCESS;
331 }
332 
333 static uint8_t avrcp_target_response_reject(avrcp_connection_t * connection, avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id, avrcp_command_opcode_t opcode, avrcp_pdu_id_t pdu_id, avrcp_status_code_t status){
334     // AVRCP_CTYPE_RESPONSE_REJECTED
335     connection->command_type = AVRCP_CTYPE_RESPONSE_REJECTED;
336     connection->subunit_type = subunit_type;
337     connection->subunit_id =   subunit_id;
338     connection->command_opcode = opcode;
339     // company id is 3 bytes long
340     int pos = connection->cmd_operands_length;
341     connection->cmd_operands[pos++] = pdu_id;
342     connection->cmd_operands[pos++] = 0;
343     // param length
344     big_endian_store_16(connection->cmd_operands, pos, 1);
345     pos += 2;
346     connection->cmd_operands[pos++] = status;
347     connection->cmd_operands_length = pos;
348     connection->state = AVCTP_W2_SEND_RESPONSE;
349     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
350     return ERROR_CODE_SUCCESS;
351 }
352 
353 static uint8_t avrcp_target_response_not_implemented(avrcp_connection_t * connection, avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id, avrcp_command_opcode_t opcode, avrcp_pdu_id_t pdu_id, uint8_t event_id){
354     connection->command_type = AVRCP_CTYPE_RESPONSE_NOT_IMPLEMENTED;
355     connection->subunit_type = subunit_type;
356     connection->subunit_id =   subunit_id;
357     connection->command_opcode = opcode;
358 
359     // company id is 3 bytes long
360     int pos = connection->cmd_operands_length;
361     connection->cmd_operands[pos++] = pdu_id;
362     connection->cmd_operands[pos++] = 0;
363     // param length
364     big_endian_store_16(connection->cmd_operands, pos, 1);
365     pos += 2;
366     connection->cmd_operands[pos++] = event_id;
367     connection->cmd_operands_length = pos;
368 
369     connection->state = AVCTP_W2_SEND_RESPONSE;
370     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
371     return ERROR_CODE_SUCCESS;
372 }
373 
374 static uint8_t avrcp_target_response_vendor_dependent_interim(avrcp_connection_t * connection, avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id,
375     avrcp_command_opcode_t opcode, avrcp_pdu_id_t pdu_id, uint8_t event_id, const uint8_t * value, uint16_t value_len){
376     connection->command_type = AVRCP_CTYPE_RESPONSE_INTERIM;
377     connection->subunit_type = subunit_type;
378     connection->subunit_id =   subunit_id;
379     connection->command_opcode = opcode;
380 
381     // company id is 3 bytes long
382     int pos = connection->cmd_operands_length;
383     connection->cmd_operands[pos++] = pdu_id;
384     connection->cmd_operands[pos++] = 0;
385     // param length
386     big_endian_store_16(connection->cmd_operands, pos, 1 + value_len);
387     pos += 2;
388     connection->cmd_operands[pos++] = event_id;
389     if (value && value_len > 0){
390         memcpy(connection->cmd_operands + pos, value, value_len);
391         pos += value_len;
392     }
393     connection->cmd_operands_length = pos;
394 
395     connection->state = AVCTP_W2_SEND_RESPONSE;
396     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
397     return ERROR_CODE_SUCCESS;
398 }
399 
400 static uint8_t avrcp_target_response_addressed_player_changed_interim(avrcp_connection_t * connection, avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id, avrcp_command_opcode_t opcode, avrcp_pdu_id_t pdu_id){
401     connection->command_type = AVRCP_CTYPE_RESPONSE_INTERIM;
402     connection->subunit_type = subunit_type;
403     connection->subunit_id =   subunit_id;
404     connection->command_opcode = opcode;
405 
406     // company id is 3 bytes long
407     int pos = connection->cmd_operands_length;
408     connection->cmd_operands[pos++] = pdu_id;
409     connection->cmd_operands[pos++] = 0;
410     // param length
411     big_endian_store_16(connection->cmd_operands, pos, 5);
412     pos += 2;
413     connection->cmd_operands[pos++] = AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED;
414     big_endian_read_16( &connection->cmd_operands[pos], connection->addressed_player_id);
415     pos += 2;
416     big_endian_read_16( &connection->cmd_operands[pos], connection->uid_counter);
417     pos += 2;
418 
419     connection->cmd_operands_length = pos;
420     connection->state = AVCTP_W2_SEND_RESPONSE;
421     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
422     return ERROR_CODE_SUCCESS;
423 }
424 
425 
426 // static uint8_t avrcp_target_response_vendor_dependent_changed(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, uint8_t event_id){
427 //     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
428 //     connection->command_type = AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
429 //     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
430 //     connection->subunit_id = AVRCP_SUBUNIT_ID;
431 
432 //     // company id is 3 bytes long
433 //     int pos = connection->cmd_operands_length;
434 //     connection->cmd_operands[pos++] = pdu_id;
435 //     connection->cmd_operands[pos++] = 0;
436 //     // param length
437 //     big_endian_store_16(connection->cmd_operands, pos, 1);
438 //     pos += 2;
439 //     connection->cmd_operands[pos++] = event_id;
440 //     connection->cmd_operands_length = pos;
441 
442 //     connection->state = AVCTP_W2_SEND_RESPONSE;
443 //     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
444 //     return ERROR_CODE_SUCCESS;
445 // }
446 
447 static uint8_t avrcp_target_pass_through_response(uint16_t avrcp_cid, avrcp_command_type_t cmd_type, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
448     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
449     if (!connection){
450         log_error("Could not find a connection.");
451         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
452     }
453     connection->command_type = cmd_type;
454     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
455     connection->subunit_id =   AVRCP_SUBUNIT_ID;
456     connection->command_opcode = AVRCP_CMD_OPCODE_PASS_THROUGH;
457 
458     int pos = 0;
459     connection->cmd_operands[pos++] = opid;
460     connection->cmd_operands[pos++] = operands_length;
461     if (operands_length == 1){
462         connection->cmd_operands[pos++] = operand;
463     }
464     connection->cmd_operands_length = pos;
465 
466     connection->state = AVCTP_W2_SEND_RESPONSE;
467     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
468     return ERROR_CODE_SUCCESS;
469 }
470 
471 uint8_t avrcp_target_operation_rejected(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
472     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_REJECTED, opid, operands_length, operand);
473 }
474 
475 uint8_t avrcp_target_operation_accepted(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
476     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_ACCEPTED, opid, operands_length, operand);
477 }
478 
479 uint8_t avrcp_target_operation_not_implemented(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
480     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_ACCEPTED, opid, operands_length, operand);
481 }
482 
483 void avrcp_target_set_unit_info(uint16_t avrcp_cid, avrcp_subunit_type_t unit_type, uint32_t company_id){
484     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
485     if (!connection){
486         log_error("avrcp_target_operation_reject: could not find a connection.");
487         return;
488     }
489     connection->unit_type = unit_type;
490     connection->company_id = company_id;
491 }
492 
493 void avrcp_target_set_subunit_info(uint16_t avrcp_cid, avrcp_subunit_type_t subunit_type, const uint8_t * subunit_info_data, uint16_t subunit_info_data_size){
494     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
495     if (!connection){
496         log_error("avrcp_target_operation_reject: could not find a connection.");
497         return;
498     }
499     connection->subunit_info_type = subunit_type;
500     connection->subunit_info_data = subunit_info_data;
501     connection->subunit_info_data_size = subunit_info_data_size;
502 }
503 
504 static uint8_t avrcp_target_unit_info(avrcp_connection_t * connection){
505     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
506 
507     uint8_t unit = 0;
508     connection->command_type = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
509     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
510     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
511     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
512 
513     connection->cmd_operands_length = 5;
514     connection->cmd_operands[0] = 0x07;
515     connection->cmd_operands[1] = (connection->unit_type << 4) | unit;
516     // company id is 3 bytes long
517     big_endian_store_32(connection->cmd_operands, 2, connection->company_id);
518 
519     connection->state = AVCTP_W2_SEND_RESPONSE;
520     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
521     return ERROR_CODE_SUCCESS;
522 }
523 
524 
525 static uint8_t avrcp_target_subunit_info(avrcp_connection_t * connection, uint8_t offset){
526     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
527     if (offset - 4 > connection->subunit_info_data_size) return AVRCP_STATUS_INVALID_PARAMETER;
528 
529     connection->command_opcode = AVRCP_CMD_OPCODE_SUBUNIT_INFO;
530     connection->command_type = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
531     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
532     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
533     // printf("avrcp_target_subunit_info  subunit_type %d\n", connection->subunit_type);
534 
535     uint8_t page = offset / 4;
536     uint8_t extension_code = 7;
537     connection->cmd_operands_length = 5;
538     connection->cmd_operands[0] = (page << 4) | extension_code;
539 
540     memcpy(connection->cmd_operands+1, connection->subunit_info_data + offset, 4);
541 
542     connection->state = AVCTP_W2_SEND_RESPONSE;
543     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
544     return ERROR_CODE_SUCCESS;
545 }
546 
547 static inline uint8_t avrcp_prepare_vendor_dependent_response(uint16_t avrcp_cid, avrcp_connection_t ** out_connection, avrcp_pdu_id_t pdu_id, uint16_t param_length){
548     *out_connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
549     if (!*out_connection){
550         log_error("avrcp tartget: could not find a connection.");
551         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
552     }
553 
554     if ((*out_connection)->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
555     (*out_connection)->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
556     (*out_connection)->command_type    = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
557     (*out_connection)->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
558     (*out_connection)->subunit_id      = AVRCP_SUBUNIT_ID;
559 
560     (*out_connection)->cmd_operands[(*out_connection)->cmd_operands_length++] = pdu_id;
561     // reserved
562     (*out_connection)->cmd_operands[(*out_connection)->cmd_operands_length++] = 0;
563     // param length
564     big_endian_store_16((*out_connection)->cmd_operands, (*out_connection)->cmd_operands_length, param_length);
565     (*out_connection)->cmd_operands_length += 2;
566     return ERROR_CODE_SUCCESS;
567 }
568 
569 static uint8_t avrcp_target_capability(uint16_t avrcp_cid, avrcp_capability_id_t capability_id, uint8_t capabilities_num, uint8_t * capabilities, uint8_t size){
570     avrcp_connection_t * connection = NULL;
571     uint8_t status = avrcp_prepare_vendor_dependent_response(avrcp_cid, &connection, AVRCP_PDU_ID_GET_CAPABILITIES, 2+size);
572     if (status != ERROR_CODE_SUCCESS) return status;
573 
574     connection->cmd_operands[connection->cmd_operands_length++] = capability_id;
575     connection->cmd_operands[connection->cmd_operands_length++] = capabilities_num;
576     memcpy(connection->cmd_operands+connection->cmd_operands_length, capabilities, size);
577     connection->cmd_operands_length += size;
578 
579     connection->state = AVCTP_W2_SEND_RESPONSE;
580     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
581     return ERROR_CODE_SUCCESS;
582 }
583 
584 uint8_t avrcp_target_supported_events(uint16_t avrcp_cid, uint8_t capabilities_num, uint8_t * capabilities, uint8_t size){
585     return avrcp_target_capability(avrcp_cid, AVRCP_CAPABILITY_ID_EVENT, capabilities_num, capabilities, size);
586 }
587 
588 uint8_t avrcp_target_supported_companies(uint16_t avrcp_cid, uint8_t capabilities_num, uint8_t * capabilities, uint8_t size ){
589     return avrcp_target_capability(avrcp_cid, AVRCP_CAPABILITY_ID_COMPANY, capabilities_num, capabilities, size);
590 }
591 
592 uint8_t avrcp_target_play_status(uint16_t avrcp_cid, uint32_t song_length_ms, uint32_t song_position_ms, avrcp_playback_status_t play_status){
593     avrcp_connection_t * connection = NULL;
594     uint8_t status = avrcp_prepare_vendor_dependent_response(avrcp_cid, &connection, AVRCP_PDU_ID_GET_PLAY_STATUS, 11);
595     if (status != ERROR_CODE_SUCCESS) return status;
596 
597     big_endian_store_32(connection->cmd_operands, connection->cmd_operands_length, song_length_ms);
598     connection->cmd_operands_length += 4;
599     big_endian_store_32(connection->cmd_operands, connection->cmd_operands_length, song_position_ms);
600     connection->cmd_operands_length += 4;
601     connection->cmd_operands[connection->cmd_operands_length++] = play_status;
602 
603     connection->state = AVCTP_W2_SEND_RESPONSE;
604     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
605     return ERROR_CODE_SUCCESS;
606 }
607 
608 static uint8_t avrcp_target_now_playing_info(avrcp_connection_t * connection){
609     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
610     connection->now_playing_info_response = 1;
611     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
612     connection->command_type    = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
613     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
614     connection->subunit_id      = AVRCP_SUBUNIT_ID;
615 
616     connection->state = AVCTP_W2_SEND_RESPONSE;
617     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
618     return ERROR_CODE_SUCCESS;
619 }
620 
621 static uint8_t avrcp_target_store_media_attr(avrcp_connection_t * connection, avrcp_media_attribute_id_t attr_id, const char * value){
622     int index = attr_id - 1;
623     if (!value) return AVRCP_STATUS_INVALID_PARAMETER;
624     connection->now_playing_info[index].value = (uint8_t*)value;
625     connection->now_playing_info[index].len   = strlen(value);
626     // printf("store %lu bytes, %s\n",  strlen(value), value);
627     return ERROR_CODE_SUCCESS;
628 }
629 
630 uint8_t avrcp_target_set_playback_status(uint16_t avrcp_cid, avrcp_playback_status_t playback_status){
631     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
632     if (!connection){
633         log_error("avrcp_unit_info: could not find a connection.");
634         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
635     }
636     if (connection->playback_status == playback_status) return ERROR_CODE_SUCCESS;
637 
638     connection->playback_status = playback_status;
639     connection->playback_status_changed = 1;
640     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
641     return ERROR_CODE_SUCCESS;
642 }
643 
644 void avrcp_target_set_now_playing_info(uint16_t avrcp_cid, const avrcp_track_t * current_track, uint16_t total_tracks){
645     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
646     if (!connection){
647         log_error("avrcp_unit_info: could not find a connection. cid 0x%02x\n", avrcp_cid);
648         return;
649     }
650     if (!current_track){
651         connection->track_selected = 0;
652         connection->playback_status = AVRCP_PLAYBACK_STATUS_ERROR;
653         return;
654     }
655     memcpy(connection->track_id, current_track->track_id, 8);
656     connection->song_length_ms = current_track->song_length_ms;
657     connection->track_nr = current_track->track_nr;
658     connection->total_tracks = total_tracks;
659     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_TITLE, current_track->title);
660     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ARTIST, current_track->artist);
661     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ALBUM, current_track->album);
662     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_GENRE, current_track->genre);
663     connection->track_selected = 1;
664 
665     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED)) {
666         connection->track_changed = 1;
667         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
668     }
669     return;
670 }
671 
672 uint8_t avrcp_target_track_changed(uint16_t avrcp_cid, uint8_t * track_id){
673     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
674     if (!connection){
675         log_error("avrcp_target_track_changed: could not find connection.");
676         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
677     }
678     if (!track_id) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
679 
680     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED)) {
681         connection->track_changed = 1;
682         memcpy(connection->track_id, track_id, 8);
683         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
684     }
685     return ERROR_CODE_SUCCESS;
686 }
687 
688 uint8_t avrcp_target_playing_content_changed(uint16_t avrcp_cid){
689     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
690     if (!connection){
691         log_error("avrcp_target_playing_content_changed: could not find a connection.");
692         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
693     }
694     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED)) {
695         connection->playing_content_changed = 1;
696         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
697     }
698     return ERROR_CODE_SUCCESS;
699 }
700 
701 uint8_t avrcp_target_addressed_player_changed(uint16_t avrcp_cid, uint16_t player_id, uint16_t uid_counter){
702     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
703     if (!connection){
704         log_error("avrcp_unit_info: could not find a connection.");
705         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
706     }
707     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED)) {
708         // printf("send AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED\n");
709         // connection->addressed_player_changed = 1;
710         connection->uid_counter = uid_counter;
711         connection->addressed_player_id = player_id;
712         // avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
713     }
714     return ERROR_CODE_SUCCESS;
715 }
716 
717 uint8_t avrcp_target_battery_status_changed(uint16_t avrcp_cid, avrcp_battery_status_t battery_status){
718     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
719     if (!connection){
720         log_error("avrcp_unit_info: could not find a connection.");
721         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
722     }
723     if (connection->battery_status == battery_status) return ERROR_CODE_SUCCESS;
724     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED)) {
725         connection->battery_status = battery_status;
726         connection->battery_status_changed = 1;
727         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
728     }
729     return ERROR_CODE_SUCCESS;
730 }
731 
732 uint8_t avrcp_target_volume_changed(uint16_t avrcp_cid, uint8_t volume_percentage){
733     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
734     if (!connection){
735         log_error("avrcp_unit_info: could not find a connection.");
736         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
737     }
738     if (connection->volume_percentage == volume_percentage) return ERROR_CODE_SUCCESS;
739     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED )) {
740         connection->volume_percentage = volume_percentage;
741         connection->volume_percentage_changed = 1;
742         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
743     }
744     return ERROR_CODE_SUCCESS;
745 }
746 
747 
748 static uint8_t * avrcp_get_company_id(uint8_t *packet, uint16_t size){
749     UNUSED(size);
750     return packet + 6;
751 }
752 
753 static uint8_t * avrcp_get_pdu(uint8_t *packet, uint16_t size){
754     UNUSED(size);
755     return packet + 9;
756 }
757 
758 static uint8_t avrcp_is_receive_pass_through_cmd(uint8_t operation_id){
759     return operation_id & 0x80;
760 }
761 
762 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
763     UNUSED(connection);
764     UNUSED(packet);
765     UNUSED(size);
766 
767     // uint8_t opcode;
768     uint16_t pid = 0;
769     uint8_t transport_header = packet[0];
770     connection->transaction_label = transport_header >> 4;
771     // uint8_t frame_type = (transport_header & 0x03) >> 1;
772     avrcp_packet_type_t packet_type = (avrcp_packet_type_t) ((transport_header & 0x0F) >> 2);
773     switch (packet_type){
774         case AVRCP_SINGLE_PACKET:
775             pid =  big_endian_read_16(packet, 1);
776             break;
777         case AVRCP_START_PACKET:
778             pid =  big_endian_read_16(packet, 2);
779             break;
780         default:
781             break;
782     }
783 
784     switch (packet_type){
785         case AVRCP_SINGLE_PACKET:
786         case AVRCP_START_PACKET:
787             if (pid != BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL){
788                 log_info("Invalid pid 0x%02x, expected 0x%02x", connection->invalid_pid, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
789                 connection->reject_transport_header = 1;
790                 connection->invalid_pid = pid;
791                 connection->transport_header = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2 ) | (AVRCP_RESPONSE_FRAME << 1) | 1;
792                 connection->state = AVCTP_W2_SEND_RESPONSE;
793                 avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
794                 return;
795             }
796             break;
797         default:
798             break;
799     }
800 
801     // avrcp_command_type_t ctype = (avrcp_command_type_t) packet[3];
802     // uint8_t byte_value = packet[4];
803     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (packet[4] >> 3);
804     avrcp_subunit_id_t   subunit_id   = (avrcp_subunit_id_t) (packet[4] & 0x07);
805     // opcode = packet[pos++];
806     // printf("    Transport header 0x%02x (transaction_label %d, packet_type %d, frame_type %d, ipid %d), pid 0x%4x\n",
807     //     transport_header, transaction_label, packet_type, frame_type, ipid, pid);
808     // printf_hexdump(packet+pos, size-pos);
809 
810     avrcp_command_opcode_t opcode = (avrcp_command_opcode_t) avrcp_cmd_opcode(packet,size);
811     uint8_t * company_id = avrcp_get_company_id(packet, size);
812     uint8_t * pdu = avrcp_get_pdu(packet, size);
813     // uint16_t param_length = big_endian_read_16(pdu, 2);
814 
815     int pos = 4;
816     uint16_t length;
817     avrcp_pdu_id_t   pdu_id;
818     connection->cmd_operands_length = 0;
819 
820     switch (opcode){
821         case AVRCP_CMD_OPCODE_UNIT_INFO:
822             avrcp_target_unit_info(connection);
823             break;
824         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
825             uint8_t offset =  4 * (packet[pos+2]>>4);
826             avrcp_target_subunit_info(connection, offset);
827             break;
828         }
829         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
830             log_info("AVRCP_OPERATION_ID 0x%02x, operands length %d, operand %d", packet[6], packet[7], packet[8]);
831             avrcp_operation_id_t operation_id = (avrcp_operation_id_t) packet[6];
832 
833             if (avrcp_is_receive_pass_through_cmd(operation_id)){
834                 operation_id = (avrcp_operation_id_t) (packet[6] & 0x7F);
835                 avrcp_target_operation_accepted(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], packet[8]);
836                 break;
837             }
838 
839             switch (operation_id){
840                 case AVRCP_OPERATION_ID_PLAY:
841                 case AVRCP_OPERATION_ID_PAUSE:
842                 case AVRCP_OPERATION_ID_STOP:
843                 case AVRCP_OPERATION_ID_VOLUME_UP:
844                 case AVRCP_OPERATION_ID_VOLUME_DOWN:
845                 case AVRCP_OPERATION_ID_REWIND:
846                 case AVRCP_OPERATION_ID_FAST_FORWARD:
847                 case AVRCP_OPERATION_ID_FORWARD:
848                 case AVRCP_OPERATION_ID_BACKWARD:
849                 case AVRCP_OPERATION_ID_SKIP:
850                 case AVRCP_OPERATION_ID_MUTE:
851                 case AVRCP_OPERATION_ID_CHANNEL_UP:
852                 case AVRCP_OPERATION_ID_CHANNEL_DOWN:
853                 case AVRCP_OPERATION_ID_SELECT:
854                 case AVRCP_OPERATION_ID_UP:
855                 case AVRCP_OPERATION_ID_DOWN:
856                 case AVRCP_OPERATION_ID_LEFT:
857                 case AVRCP_OPERATION_ID_RIGHT:
858                 case AVRCP_OPERATION_ID_ROOT_MENU:
859                     avrcp_target_operation_accepted(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], packet[8]);
860                     avrcp_target_emit_operation(avrcp_target_context.avrcp_callback, connection->avrcp_cid, operation_id, packet[7], packet[8]);
861                     break;
862                 case AVRCP_OPERATION_ID_UNDEFINED:
863                     avrcp_target_operation_not_implemented(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], packet[8]);
864                     return;
865                 default:
866                     avrcp_target_operation_not_implemented(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], packet[8]);
867                     return;
868             }
869             break;
870         }
871 
872         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
873             pdu_id = (avrcp_pdu_id_t) pdu[0];
874             // 1 - reserved
875             // 2-3 param length,
876             length = big_endian_read_16(pdu, 2);
877             memcpy(connection->cmd_operands, company_id, 3);
878             connection->cmd_operands_length = 3;
879             switch (pdu_id){
880                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:{
881                     if (length == 0){
882                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PLAYER_ID);
883                         break;
884                     }
885                     avrcp_target_response_accept(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_SUCCESS);
886                     break;
887                 }
888                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
889                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) pdu[pos];
890                     switch (capability_id){
891                         case AVRCP_CAPABILITY_ID_EVENT:
892                             avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_EVENT_IDS_QUERY);
893                             break;
894                         case AVRCP_CAPABILITY_ID_COMPANY:
895                             avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_COMPANY_IDS_QUERY);
896                             break;
897                         default:
898                             avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
899                             break;
900                     }
901                     break;
902                 }
903                 case AVRCP_PDU_ID_GET_PLAY_STATUS:
904                     avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_PLAY_STATUS_QUERY);
905                     break;
906                 case AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE:
907                     connection->cmd_operands[0] = pdu[4];
908                     connection->abort_continue_response = 1;
909                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
910                     break;
911                 case AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE:
912                     if (pdu[4] != AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES){
913                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
914                         return;
915                     }
916                     connection->now_playing_info_response = 1;
917                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
918                     break;
919                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
920                     uint8_t play_identifier[8];
921                     memset(play_identifier, 0, 8);
922                     if (memcmp(pdu+pos, play_identifier, 8) != 0) {
923                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
924                         return;
925                     }
926                     pos += 8;
927                     uint8_t attribute_count = pdu[pos++];
928                     // printf("AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES attribute count %d\n", attribute_count);
929                     connection->next_attr_id = AVRCP_MEDIA_ATTR_NONE;
930                     if (!attribute_count){
931                         connection->now_playing_info_attr_bitmap = 0xFE;
932                     } else {
933                         int i;
934                         connection->now_playing_info_attr_bitmap = 0;
935                         for (i=0; i < attribute_count; i++){
936                             uint16_t attr_id = big_endian_read_16(pdu, pos);
937                             pos += 2;
938                             connection->now_playing_info_attr_bitmap |= (1 << attr_id);
939                         }
940                     }
941                     log_info("now_playing_info_attr_bitmap 0x%02x", connection->now_playing_info_attr_bitmap);
942                     avrcp_target_now_playing_info(connection);
943                     break;
944                 }
945                 case AVRCP_PDU_ID_REGISTER_NOTIFICATION:{
946                     // 0 - pdu id
947                     // 1 - reserved
948                     // 2-3 param length
949                     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) pdu[4];
950                     uint16_t event_mask = (1 << event_id);
951 
952                     switch (event_id){
953                         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:
954                             connection->notifications_enabled |= event_mask;
955                             if (connection->track_selected){
956                                 avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_SELECTED, 8);
957                             } else {
958                                 avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_NOT_SELECTED, 8);
959                             }
960                             break;
961                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:
962                             connection->notifications_enabled |= event_mask;
963                             avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, (const uint8_t *)&connection->playback_status, 1);
964                             break;
965                         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:
966                             connection->notifications_enabled |= event_mask;
967                             avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, NULL, 0);
968                             break;
969                         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:
970                             connection->notifications_enabled |= event_mask;
971                             avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, (const uint8_t *)&connection->volume_percentage, 1);
972                             break;
973                         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:
974                             connection->notifications_enabled |= event_mask;
975                             avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, (const uint8_t *)&connection->battery_status, 1);
976                             break;
977                         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:
978                         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
979                         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:
980                             avrcp_target_response_not_implemented(connection, subunit_type, subunit_id, opcode, pdu_id, event_id);
981                             return;
982                         case AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED:
983                             connection->notifications_enabled |= event_mask;
984                             avrcp_target_response_addressed_player_changed_interim(connection, subunit_type, subunit_id, opcode, pdu_id);
985                             return;
986                         default:
987                             avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
988                             return;
989                     }
990                     break;
991                 }
992                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME: {
993                     if (length != 1){
994                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
995                         break;
996                     }
997 
998                     uint8_t absolute_volume = pdu[4];
999                     if (absolute_volume < 0x80){
1000                         connection->volume_percentage = absolute_volume;
1001                     }
1002                     avrcp_target_response_accept(connection, subunit_type, subunit_id, opcode, pdu_id, (avrcp_status_code_t) connection->volume_percentage);
1003                     break;
1004                 }
1005                 default:
1006                     log_info("AVRCP target: unhandled pdu id 0x%02x", pdu_id);
1007                     avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
1008                     break;
1009             }
1010             break;
1011         default:
1012             log_info("AVRCP target: opcode 0x%02x not implemented", avrcp_cmd_opcode(packet,size));
1013             break;
1014     }
1015 }
1016 
1017 #if 0
1018 static int avrcp_target_send_addressed_player_changed_notification(uint16_t cid, avrcp_connection_t * connection, uint16_t uid, uint16_t uid_counter){
1019     if (!connection){
1020         log_error("avrcp tartget: could not find a connection.");
1021         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1022     }
1023     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1024     connection->command_type    = AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
1025     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
1026     connection->subunit_id      = AVRCP_SUBUNIT_ID;
1027 
1028     uint16_t pos = 0;
1029     l2cap_reserve_packet_buffer();
1030     uint8_t * packet = l2cap_get_outgoing_buffer();
1031 
1032     connection->packet_type = AVRCP_SINGLE_PACKET;
1033     packet[pos++] = (connection->transaction_label << 4) | (connection->packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
1034     // Profile IDentifier (PID)
1035     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
1036     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
1037 
1038     // command_type
1039     packet[pos++] = connection->command_type;
1040     // subunit_type | subunit ID
1041     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
1042     // opcode
1043     packet[pos++] = (uint8_t)connection->command_opcode;
1044 
1045     // company id is 3 bytes long
1046     big_endian_store_24(packet, pos, BT_SIG_COMPANY_ID);
1047     pos += 3;
1048 
1049     packet[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
1050     packet[pos++] = 0;
1051     big_endian_store_16(packet, pos, 5);
1052     pos += 2;
1053     packet[pos++] = AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED;
1054     big_endian_store_16(packet, pos, uid);
1055     pos += 2;
1056     big_endian_store_16(packet, pos, uid_counter);
1057     pos += 2;
1058 
1059     connection->wait_to_send = 0;
1060     return l2cap_send_prepared(cid, pos);
1061 }
1062 #endif
1063 
1064 static int avrcp_target_send_notification(uint16_t cid, avrcp_connection_t * connection, uint8_t notification_id, uint8_t * value, uint16_t value_len){
1065     if (!connection){
1066         log_error("avrcp tartget: could not find a connection.");
1067         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1068     }
1069 
1070     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1071     connection->command_type    = AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
1072     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
1073     connection->subunit_id      = AVRCP_SUBUNIT_ID;
1074 
1075     uint16_t pos = 0;
1076     l2cap_reserve_packet_buffer();
1077     uint8_t * packet = l2cap_get_outgoing_buffer();
1078     uint16_t  size   = l2cap_get_remote_mtu_for_local_cid(connection->l2cap_signaling_cid);
1079 
1080     connection->packet_type = AVRCP_SINGLE_PACKET;
1081     packet[pos++] = (connection->transaction_label << 4) | (connection->packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
1082     // Profile IDentifier (PID)
1083     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
1084     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
1085 
1086     // command_type
1087     packet[pos++] = connection->command_type;
1088     // subunit_type | subunit ID
1089     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
1090     // opcode
1091     packet[pos++] = (uint8_t)connection->command_opcode;
1092 
1093     // company id is 3 bytes long
1094     big_endian_store_24(packet, pos, BT_SIG_COMPANY_ID);
1095     pos += 3;
1096 
1097     packet[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
1098     packet[pos++] = 0;
1099     uint16_t remainig_outgoing_buffer_size = size > (value_len + 2 + 1) ? size - (value_len + 2 + 1): 0;
1100     uint16_t caped_value_len = value_len > remainig_outgoing_buffer_size ? remainig_outgoing_buffer_size : value_len;
1101     big_endian_store_16(packet, pos, caped_value_len);
1102     pos += 2;
1103     packet[pos++] = notification_id;
1104 
1105     memcpy(packet+pos, value, caped_value_len);
1106     pos += caped_value_len;
1107     connection->wait_to_send = 0;
1108     return l2cap_send_prepared(cid, pos);
1109 }
1110 
1111 static void avrcp_target_reset_notification(avrcp_connection_t * connection, uint8_t notification_id){
1112     if (!connection){
1113         log_error("avrcp tartget: could not find a connection.");
1114         return;
1115     }
1116     connection->notifications_enabled &= ~(1 << notification_id);
1117     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1118 
1119 }
1120 
1121 static void avrcp_target_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1122     avrcp_connection_t * connection;
1123     switch (packet_type) {
1124         case L2CAP_DATA_PACKET:
1125             connection = get_avrcp_connection_for_l2cap_signaling_cid(channel, &avrcp_target_context);
1126             if (!connection) break;
1127             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1128             break;
1129         case HCI_EVENT_PACKET:
1130             switch (hci_event_packet_get_type(packet)){
1131                 case L2CAP_EVENT_CAN_SEND_NOW:{
1132                     connection = get_avrcp_connection_for_l2cap_signaling_cid(channel, &avrcp_target_context);
1133                     if (!connection) {
1134                         log_error("Connection not found\n");
1135                         break;
1136                     }
1137 
1138                     if (connection->abort_continue_response){
1139                         connection->abort_continue_response = 0;
1140                         connection->now_playing_info_response = 0;
1141                         avrcp_target_abort_continue_response(connection->l2cap_signaling_cid, connection);
1142                         break;
1143                     }
1144 
1145                     if (connection->now_playing_info_response){
1146                         connection->now_playing_info_response = 0;
1147                         avrcp_target_send_now_playing_info(connection->l2cap_signaling_cid, connection);
1148                         break;
1149                     }
1150 
1151                     if (connection->track_changed){
1152                         connection->track_changed = 0;
1153                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED, connection->track_id, 8);
1154                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED);
1155                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1156                         break;
1157                     }
1158 
1159                     if (connection->playback_status_changed){
1160                         connection->playback_status_changed = 0;
1161                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED, &connection->playback_status_changed, 1);
1162                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED);
1163                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1164                         break;
1165                     }
1166 
1167                     // if (connection->addressed_player_changed){
1168                     //     connection->playback_status_changed = 0;
1169                     //     avrcp_target_send_addressed_player_changed_notification(connection->l2cap_signaling_cid, connection, connection->addressed_player_id, connection->uid_counter);
1170                     //     avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED);
1171                     //     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1172                     //     break;
1173                     // }
1174 
1175                     if (connection->playing_content_changed){
1176                         connection->playing_content_changed = 0;
1177                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED, NULL, 0);
1178                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED);
1179                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1180                         break;
1181                     }
1182 
1183                     if (connection->battery_status_changed){
1184                         connection->battery_status_changed = 0;
1185                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED, (uint8_t *)&connection->battery_status, 1);
1186                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED);
1187                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1188                         break;
1189                     }
1190 
1191                     if (connection->volume_percentage_changed){
1192                         connection->volume_percentage_changed = 0;
1193                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED, &connection->volume_percentage, 1);
1194                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED);
1195                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1196                         break;
1197                     }
1198 
1199                     if (connection->reject_transport_header){
1200                         printf(" reject_transport_header\n");
1201                         connection->state = AVCTP_CONNECTION_OPENED;
1202                         connection->reject_transport_header = 0;
1203                         l2cap_reserve_packet_buffer();
1204                         uint8_t * out_buffer = l2cap_get_outgoing_buffer();
1205                         out_buffer[0] = connection->transport_header;
1206                         big_endian_store_16(out_buffer, 1, connection->invalid_pid);
1207                         l2cap_send_prepared(connection->l2cap_signaling_cid, 3);
1208                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1209                         break;
1210                     }
1211 
1212 
1213                     switch (connection->state){
1214                         case AVCTP_W2_SEND_RESPONSE:
1215                             connection->state = AVCTP_CONNECTION_OPENED;
1216                             // if (connection->now_playing_info_response){
1217                             //     connection->now_playing_info_response = 0;
1218                             //     avrcp_target_send_now_playing_info(connection->l2cap_signaling_cid, connection);
1219                             //     break;
1220                             // }
1221                             avrcp_target_send_response(connection->l2cap_signaling_cid, connection);
1222                             break;
1223                         default:
1224                             return;
1225                     }
1226                     break;
1227             }
1228             default:
1229                 avrcp_packet_handler(packet_type, channel, packet, size, &avrcp_target_context);
1230                 break;
1231         }
1232         default:
1233             break;
1234     }
1235 }
1236 
1237 void avrcp_target_init(void){
1238     avrcp_target_context.role = AVRCP_TARGET;
1239     avrcp_target_context.connections = NULL;
1240     avrcp_target_context.packet_handler = avrcp_target_packet_handler;
1241     l2cap_register_service(&avrcp_target_packet_handler, BLUETOOTH_PROTOCOL_AVCTP, 0xffff, LEVEL_2);
1242 }
1243 
1244 void avrcp_target_register_packet_handler(btstack_packet_handler_t callback){
1245     if (callback == NULL){
1246         log_error("avrcp_register_packet_handler called with NULL callback");
1247         return;
1248     }
1249     avrcp_target_context.avrcp_callback = callback;
1250 }
1251 
1252 uint8_t avrcp_target_connect(bd_addr_t bd_addr, uint16_t * avrcp_cid){
1253     return avrcp_connect(bd_addr, &avrcp_target_context, avrcp_cid);
1254 }
1255 
1256 uint8_t avrcp_target_disconnect(uint16_t avrcp_cid){
1257     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
1258     if (!connection){
1259         log_error("avrcp_get_capabilities: could not find a connection.");
1260         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1261     }
1262     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1263     l2cap_disconnect(connection->l2cap_signaling_cid, 0);
1264     return ERROR_CODE_SUCCESS;
1265 }
1266 
1267