xref: /btstack/src/classic/avrcp_target.c (revision 0a2feef458dae6671ad6c9bf9fbe762e09aee3ab)
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++;
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             connection->next_attr_id++;
255         }
256     }
257 
258     if (fragmented){
259         switch (connection->packet_type){
260             case AVRCP_SINGLE_PACKET:
261                 connection->packet_type = AVRCP_START_PACKET;
262                 break;
263             default:
264                 connection->packet_type = AVRCP_CONTINUE_PACKET;
265                 break;
266         }
267     } else {
268         if (connection->next_attr_id >= AVRCP_MEDIA_ATTR_SONG_LENGTH_MS){ // DONE
269             if (connection->packet_type != AVRCP_SINGLE_PACKET){
270                 connection->packet_type = AVRCP_END_PACKET;
271             }
272         }
273     }
274     packet[pos_packet_type] = connection->packet_type;
275     // store attr value length
276     big_endian_store_16(packet, playing_info_buffer_len_position, pos - playing_info_buffer_len_position - 2);
277     return l2cap_send_prepared(cid, size);
278 }
279 
280 
281 
282 static int avrcp_target_send_response(uint16_t cid, avrcp_connection_t * connection){
283     int pos = 0;
284     l2cap_reserve_packet_buffer();
285     uint8_t * packet = l2cap_get_outgoing_buffer();
286 
287     // transport header
288     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
289 
290     // TODO: check for fragmentation
291     connection->packet_type = AVRCP_SINGLE_PACKET;
292 
293     packet[pos++] = (connection->transaction_label << 4) | (connection->packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
294     // Profile IDentifier (PID)
295     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
296     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
297     // command_type
298     packet[pos++] = connection->command_type;
299     // subunit_type | subunit ID
300     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
301     // opcode
302     packet[pos++] = (uint8_t)connection->command_opcode;
303     // operands
304     memcpy(packet+pos, connection->cmd_operands, connection->cmd_operands_length);
305     // printf_hexdump(packet+pos, connection->cmd_operands_length);
306 
307     pos += connection->cmd_operands_length;
308     connection->wait_to_send = 0;
309     return l2cap_send_prepared(cid, pos);
310 }
311 
312 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){
313     // AVRCP_CTYPE_RESPONSE_REJECTED
314     connection->command_type = AVRCP_CTYPE_RESPONSE_ACCEPTED;
315     connection->subunit_type = subunit_type;
316     connection->subunit_id =   subunit_id;
317     connection->command_opcode = opcode;
318     // company id is 3 bytes long
319     int pos = connection->cmd_operands_length;
320     connection->cmd_operands[pos++] = pdu_id;
321     connection->cmd_operands[pos++] = 0;
322     // param length
323     big_endian_store_16(connection->cmd_operands, pos, 1);
324     pos += 2;
325     connection->cmd_operands[pos++] = status;
326     connection->cmd_operands_length = pos;
327     connection->state = AVCTP_W2_SEND_RESPONSE;
328     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
329     return ERROR_CODE_SUCCESS;
330 }
331 
332 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){
333     // AVRCP_CTYPE_RESPONSE_REJECTED
334     connection->command_type = AVRCP_CTYPE_RESPONSE_REJECTED;
335     connection->subunit_type = subunit_type;
336     connection->subunit_id =   subunit_id;
337     connection->command_opcode = opcode;
338     // company id is 3 bytes long
339     int pos = connection->cmd_operands_length;
340     connection->cmd_operands[pos++] = pdu_id;
341     connection->cmd_operands[pos++] = 0;
342     // param length
343     big_endian_store_16(connection->cmd_operands, pos, 1);
344     pos += 2;
345     connection->cmd_operands[pos++] = status;
346     connection->cmd_operands_length = pos;
347     connection->state = AVCTP_W2_SEND_RESPONSE;
348     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
349     return ERROR_CODE_SUCCESS;
350 }
351 
352 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){
353     connection->command_type = AVRCP_CTYPE_RESPONSE_NOT_IMPLEMENTED;
354     connection->subunit_type = subunit_type;
355     connection->subunit_id =   subunit_id;
356     connection->command_opcode = opcode;
357 
358     // company id is 3 bytes long
359     int pos = connection->cmd_operands_length;
360     connection->cmd_operands[pos++] = pdu_id;
361     connection->cmd_operands[pos++] = 0;
362     // param length
363     big_endian_store_16(connection->cmd_operands, pos, 1);
364     pos += 2;
365     connection->cmd_operands[pos++] = event_id;
366     connection->cmd_operands_length = pos;
367 
368     connection->state = AVCTP_W2_SEND_RESPONSE;
369     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
370     return ERROR_CODE_SUCCESS;
371 }
372 
373 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,
374     avrcp_command_opcode_t opcode, avrcp_pdu_id_t pdu_id, uint8_t event_id, const uint8_t * value, uint16_t value_len){
375     connection->command_type = AVRCP_CTYPE_RESPONSE_INTERIM;
376     connection->subunit_type = subunit_type;
377     connection->subunit_id =   subunit_id;
378     connection->command_opcode = opcode;
379 
380     // company id is 3 bytes long
381     int pos = connection->cmd_operands_length;
382     connection->cmd_operands[pos++] = pdu_id;
383     connection->cmd_operands[pos++] = 0;
384     // param length
385     big_endian_store_16(connection->cmd_operands, pos, 1 + value_len);
386     pos += 2;
387     connection->cmd_operands[pos++] = event_id;
388     if (value && value_len > 0){
389         memcpy(connection->cmd_operands + pos, value, value_len);
390         pos += value_len;
391     }
392     connection->cmd_operands_length = pos;
393 
394     connection->state = AVCTP_W2_SEND_RESPONSE;
395     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
396     return ERROR_CODE_SUCCESS;
397 }
398 
399 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){
400     connection->command_type = AVRCP_CTYPE_RESPONSE_INTERIM;
401     connection->subunit_type = subunit_type;
402     connection->subunit_id =   subunit_id;
403     connection->command_opcode = opcode;
404 
405     // company id is 3 bytes long
406     int pos = connection->cmd_operands_length;
407     connection->cmd_operands[pos++] = pdu_id;
408     connection->cmd_operands[pos++] = 0;
409     // param length
410     big_endian_store_16(connection->cmd_operands, pos, 5);
411     pos += 2;
412     connection->cmd_operands[pos++] = AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED;
413     big_endian_read_16( &connection->cmd_operands[pos], connection->addressed_player_id);
414     pos += 2;
415     big_endian_read_16( &connection->cmd_operands[pos], connection->uid_counter);
416     pos += 2;
417 
418     connection->cmd_operands_length = pos;
419     connection->state = AVCTP_W2_SEND_RESPONSE;
420     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
421     return ERROR_CODE_SUCCESS;
422 }
423 
424 
425 // static uint8_t avrcp_target_response_vendor_dependent_changed(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, uint8_t event_id){
426 //     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
427 //     connection->command_type = AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
428 //     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
429 //     connection->subunit_id = AVRCP_SUBUNIT_ID;
430 
431 //     // company id is 3 bytes long
432 //     int pos = connection->cmd_operands_length;
433 //     connection->cmd_operands[pos++] = pdu_id;
434 //     connection->cmd_operands[pos++] = 0;
435 //     // param length
436 //     big_endian_store_16(connection->cmd_operands, pos, 1);
437 //     pos += 2;
438 //     connection->cmd_operands[pos++] = event_id;
439 //     connection->cmd_operands_length = pos;
440 
441 //     connection->state = AVCTP_W2_SEND_RESPONSE;
442 //     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
443 //     return ERROR_CODE_SUCCESS;
444 // }
445 
446 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){
447     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
448     if (!connection){
449         log_error("Could not find a connection.");
450         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
451     }
452     connection->command_type = cmd_type;
453     connection->subunit_type = AVRCP_SUBUNIT_TYPE_PANEL;
454     connection->subunit_id =   AVRCP_SUBUNIT_ID;
455     connection->command_opcode = AVRCP_CMD_OPCODE_PASS_THROUGH;
456 
457     int pos = 0;
458     connection->cmd_operands[pos++] = opid;
459     connection->cmd_operands[pos++] = operands_length;
460     if (operands_length == 1){
461         connection->cmd_operands[pos++] = operand;
462     }
463     connection->cmd_operands_length = pos;
464 
465     connection->state = AVCTP_W2_SEND_RESPONSE;
466     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
467     return ERROR_CODE_SUCCESS;
468 }
469 
470 uint8_t avrcp_target_operation_rejected(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
471     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_REJECTED, opid, operands_length, operand);
472 }
473 
474 uint8_t avrcp_target_operation_accepted(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
475     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_ACCEPTED, opid, operands_length, operand);
476 }
477 
478 uint8_t avrcp_target_operation_not_implemented(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
479     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_ACCEPTED, opid, operands_length, operand);
480 }
481 
482 void avrcp_target_set_unit_info(uint16_t avrcp_cid, avrcp_subunit_type_t unit_type, uint32_t company_id){
483     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
484     if (!connection){
485         log_error("avrcp_target_operation_reject: could not find a connection.");
486         return;
487     }
488     connection->unit_type = unit_type;
489     connection->company_id = company_id;
490 }
491 
492 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){
493     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
494     if (!connection){
495         log_error("avrcp_target_operation_reject: could not find a connection.");
496         return;
497     }
498     connection->subunit_info_type = subunit_type;
499     connection->subunit_info_data = subunit_info_data;
500     connection->subunit_info_data_size = subunit_info_data_size;
501 }
502 
503 static uint8_t avrcp_target_unit_info(avrcp_connection_t * connection){
504     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
505 
506     uint8_t unit = 0;
507     connection->command_type = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
508     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
509     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
510     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
511 
512     connection->cmd_operands_length = 5;
513     connection->cmd_operands[0] = 0x07;
514     connection->cmd_operands[1] = (connection->unit_type << 4) | unit;
515     // company id is 3 bytes long
516     big_endian_store_32(connection->cmd_operands, 2, connection->company_id);
517 
518     connection->state = AVCTP_W2_SEND_RESPONSE;
519     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
520     return ERROR_CODE_SUCCESS;
521 }
522 
523 static uint8_t avrcp_target_subunit_info(avrcp_connection_t * connection, uint8_t offset){
524     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
525     if (offset - 4 > connection->subunit_info_data_size) return AVRCP_STATUS_INVALID_PARAMETER;
526 
527     connection->command_opcode = AVRCP_CMD_OPCODE_SUBUNIT_INFO;
528     connection->command_type = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
529     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
530     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
531     // printf("avrcp_target_subunit_info  subunit_type %d\n", connection->subunit_type);
532 
533     uint8_t page = offset / 4;
534     uint8_t extension_code = 7;
535     connection->cmd_operands_length = 5;
536     connection->cmd_operands[0] = (page << 4) | extension_code;
537 
538     memcpy(connection->cmd_operands+1, connection->subunit_info_data + offset, 4);
539 
540     connection->state = AVCTP_W2_SEND_RESPONSE;
541     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
542     return ERROR_CODE_SUCCESS;
543 }
544 
545 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){
546     *out_connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
547     if (!*out_connection){
548         log_error("avrcp tartget: could not find a connection.");
549         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
550     }
551 
552     if ((*out_connection)->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
553     (*out_connection)->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
554     (*out_connection)->command_type    = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
555     (*out_connection)->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
556     (*out_connection)->subunit_id      = AVRCP_SUBUNIT_ID;
557 
558     (*out_connection)->cmd_operands[(*out_connection)->cmd_operands_length++] = pdu_id;
559     // reserved
560     (*out_connection)->cmd_operands[(*out_connection)->cmd_operands_length++] = 0;
561     // param length
562     big_endian_store_16((*out_connection)->cmd_operands, (*out_connection)->cmd_operands_length, param_length);
563     (*out_connection)->cmd_operands_length += 2;
564     return ERROR_CODE_SUCCESS;
565 }
566 
567 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){
568     avrcp_connection_t * connection = NULL;
569     uint8_t status = avrcp_prepare_vendor_dependent_response(avrcp_cid, &connection, AVRCP_PDU_ID_GET_CAPABILITIES, 2+size);
570     if (status != ERROR_CODE_SUCCESS) return status;
571 
572     connection->cmd_operands[connection->cmd_operands_length++] = capability_id;
573     connection->cmd_operands[connection->cmd_operands_length++] = capabilities_num;
574     memcpy(connection->cmd_operands+connection->cmd_operands_length, capabilities, size);
575     connection->cmd_operands_length += size;
576 
577     connection->state = AVCTP_W2_SEND_RESPONSE;
578     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
579     return ERROR_CODE_SUCCESS;
580 }
581 
582 uint8_t avrcp_target_supported_events(uint16_t avrcp_cid, uint8_t capabilities_num, uint8_t * capabilities, uint8_t size){
583     return avrcp_target_capability(avrcp_cid, AVRCP_CAPABILITY_ID_EVENT, capabilities_num, capabilities, size);
584 }
585 
586 uint8_t avrcp_target_supported_companies(uint16_t avrcp_cid, uint8_t capabilities_num, uint8_t * capabilities, uint8_t size ){
587     return avrcp_target_capability(avrcp_cid, AVRCP_CAPABILITY_ID_COMPANY, capabilities_num, capabilities, size);
588 }
589 
590 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){
591     avrcp_connection_t * connection = NULL;
592     uint8_t status = avrcp_prepare_vendor_dependent_response(avrcp_cid, &connection, AVRCP_PDU_ID_GET_PLAY_STATUS, 11);
593     if (status != ERROR_CODE_SUCCESS) return status;
594 
595     big_endian_store_32(connection->cmd_operands, connection->cmd_operands_length, song_length_ms);
596     connection->cmd_operands_length += 4;
597     big_endian_store_32(connection->cmd_operands, connection->cmd_operands_length, song_position_ms);
598     connection->cmd_operands_length += 4;
599     connection->cmd_operands[connection->cmd_operands_length++] = play_status;
600 
601     connection->state = AVCTP_W2_SEND_RESPONSE;
602     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
603     return ERROR_CODE_SUCCESS;
604 }
605 
606 static uint8_t avrcp_target_now_playing_info(avrcp_connection_t * connection){
607     connection->now_playing_info_response = 1;
608     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
609     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
610     connection->command_type    = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
611     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
612     connection->subunit_id      = AVRCP_SUBUNIT_ID;
613 
614     connection->state = AVCTP_W2_SEND_RESPONSE;
615     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
616     return ERROR_CODE_SUCCESS;
617 }
618 
619 static uint8_t avrcp_target_store_media_attr(avrcp_connection_t * connection, avrcp_media_attribute_id_t attr_id, const char * value){
620     int index = attr_id - 1;
621     if (!value) return AVRCP_STATUS_INVALID_PARAMETER;
622     connection->now_playing_info[index].value = (uint8_t*)value;
623     connection->now_playing_info[index].len   = strlen(value);
624     // printf("store %lu bytes, %s\n",  strlen(value), value);
625     return ERROR_CODE_SUCCESS;
626 }
627 
628 uint8_t avrcp_target_set_playback_status(uint16_t avrcp_cid, avrcp_playback_status_t playback_status){
629     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
630     if (!connection){
631         log_error("avrcp_unit_info: could not find a connection.");
632         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
633     }
634     if (connection->playback_status == playback_status) return ERROR_CODE_SUCCESS;
635 
636     connection->playback_status = playback_status;
637     connection->playback_status_changed = 1;
638     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
639     return ERROR_CODE_SUCCESS;
640 }
641 
642 void avrcp_target_set_now_playing_info(uint16_t avrcp_cid, const avrcp_track_t * current_track, uint16_t total_tracks){
643     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
644     if (!connection){
645         log_error("avrcp_unit_info: could not find a connection. cid 0x%02x\n", avrcp_cid);
646         return;
647     }
648     if (!current_track){
649         connection->track_selected = 0;
650         connection->playback_status = AVRCP_PLAYBACK_STATUS_ERROR;
651         return;
652     }
653     memcpy(connection->track_id, current_track->track_id, 8);
654     connection->song_length_ms = current_track->song_length_ms;
655     connection->track_nr = current_track->track_nr;
656     connection->total_tracks = total_tracks;
657     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_TITLE, current_track->title);
658     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ARTIST, current_track->artist);
659     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ALBUM, current_track->album);
660     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_GENRE, current_track->genre);
661     connection->track_selected = 1;
662 
663     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED)) {
664         connection->track_changed = 1;
665         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
666     }
667     return;
668 }
669 
670 uint8_t avrcp_target_track_changed(uint16_t avrcp_cid, uint8_t * track_id){
671     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
672     if (!connection){
673         log_error("avrcp_target_track_changed: could not find connection.");
674         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
675     }
676     if (!track_id) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
677 
678     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED)) {
679         connection->track_changed = 1;
680         memcpy(connection->track_id, track_id, 8);
681         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
682     }
683     return ERROR_CODE_SUCCESS;
684 }
685 
686 uint8_t avrcp_target_playing_content_changed(uint16_t avrcp_cid){
687     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
688     if (!connection){
689         log_error("avrcp_target_playing_content_changed: could not find a connection.");
690         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
691     }
692     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED)) {
693         connection->playing_content_changed = 1;
694         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
695     }
696     return ERROR_CODE_SUCCESS;
697 }
698 
699 uint8_t avrcp_target_addressed_player_changed(uint16_t avrcp_cid, uint16_t player_id, uint16_t uid_counter){
700     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
701     if (!connection){
702         log_error("avrcp_unit_info: could not find a connection.");
703         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
704     }
705     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED)) {
706         // printf("send AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED\n");
707         // connection->addressed_player_changed = 1;
708         connection->uid_counter = uid_counter;
709         connection->addressed_player_id = player_id;
710         // avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
711     }
712     return ERROR_CODE_SUCCESS;
713 }
714 
715 uint8_t avrcp_target_battery_status_changed(uint16_t avrcp_cid, avrcp_battery_status_t battery_status){
716     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
717     if (!connection){
718         log_error("avrcp_unit_info: could not find a connection.");
719         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
720     }
721     if (connection->battery_status == battery_status) return ERROR_CODE_SUCCESS;
722     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED)) {
723         connection->battery_status = battery_status;
724         connection->battery_status_changed = 1;
725         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
726     }
727     return ERROR_CODE_SUCCESS;
728 }
729 
730 uint8_t avrcp_target_volume_changed(uint16_t avrcp_cid, uint8_t volume_percentage){
731     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
732     if (!connection){
733         log_error("avrcp_unit_info: could not find a connection.");
734         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
735     }
736     if (connection->volume_percentage == volume_percentage) return ERROR_CODE_SUCCESS;
737     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED )) {
738         connection->volume_percentage = volume_percentage;
739         connection->volume_percentage_changed = 1;
740         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
741     }
742     return ERROR_CODE_SUCCESS;
743 }
744 
745 
746 static uint8_t * avrcp_get_company_id(uint8_t *packet, uint16_t size){
747     UNUSED(size);
748     return packet + 6;
749 }
750 
751 static uint8_t * avrcp_get_pdu(uint8_t *packet, uint16_t size){
752     UNUSED(size);
753     return packet + 9;
754 }
755 
756 static uint8_t avrcp_is_receive_pass_through_cmd(uint8_t operation_id){
757     return operation_id & 0x80;
758 }
759 
760 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
761     UNUSED(connection);
762     UNUSED(packet);
763     UNUSED(size);
764 
765     // uint8_t opcode;
766 
767     uint8_t transport_header = packet[0];
768     connection->transaction_label = transport_header >> 4;
769     // uint8_t packet_type = (transport_header & 0x0F) >> 2;
770     // uint8_t frame_type = (transport_header & 0x03) >> 1;
771     // uint8_t ipid = transport_header & 0x01;
772     // uint8_t byte_value = packet[2];
773     // uint16_t pid = (byte_value << 8) | packet[2];
774     // avrcp_command_type_t ctype = (avrcp_command_type_t) packet[3];
775     // uint8_t byte_value = packet[4];
776     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (packet[4] >> 3);
777     avrcp_subunit_id_t   subunit_id   = (avrcp_subunit_id_t) (packet[4] & 0x07);
778     // opcode = packet[pos++];
779 
780     // printf("    Transport header 0x%02x (transaction_label %d, packet_type %d, frame_type %d, ipid %d), pid 0x%4x\n",
781     //     transport_header, transaction_label, packet_type, frame_type, ipid, pid);
782     // printf_hexdump(packet+pos, size-pos);
783 
784     avrcp_command_opcode_t opcode = avrcp_cmd_opcode(packet,size);
785     uint8_t * company_id = avrcp_get_company_id(packet, size);
786     uint8_t * pdu = avrcp_get_pdu(packet, size);
787     // uint16_t param_length = big_endian_read_16(pdu, 2);
788 
789     int pos = 4;
790     uint8_t   pdu_id;
791     connection->cmd_operands_length = 0;
792 
793     switch (opcode){
794         case AVRCP_CMD_OPCODE_UNIT_INFO:
795             avrcp_target_unit_info(connection);
796             break;
797         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:{
798             uint8_t offset =  4 * (packet[pos+2]>>4);
799             avrcp_target_subunit_info(connection, offset);
800             break;
801         }
802         case AVRCP_CMD_OPCODE_PASS_THROUGH:{
803             log_info("AVRCP_OPERATION_ID 0x%02x, operands length %d, operand %d", packet[6], packet[7], packet[8]);
804             avrcp_operation_id_t operation_id = packet[6];
805 
806             if (avrcp_is_receive_pass_through_cmd(operation_id)){
807                 operation_id = packet[6] & 0x7F;
808                 avrcp_target_operation_accepted(connection->avrcp_cid, packet[6], packet[7], packet[8]);
809                 break;
810             }
811 
812             switch (operation_id){
813                 case AVRCP_OPERATION_ID_PLAY:
814                 case AVRCP_OPERATION_ID_PAUSE:
815                 case AVRCP_OPERATION_ID_STOP:
816                 case AVRCP_OPERATION_ID_VOLUME_UP:
817                 case AVRCP_OPERATION_ID_VOLUME_DOWN:
818                 case AVRCP_OPERATION_ID_REWIND:
819                 case AVRCP_OPERATION_ID_FAST_FORWARD:
820                 case AVRCP_OPERATION_ID_FORWARD:
821                 case AVRCP_OPERATION_ID_BACKWARD:
822                 case AVRCP_OPERATION_ID_SKIP:
823                 case AVRCP_OPERATION_ID_MUTE:
824                 case AVRCP_OPERATION_ID_CHANNEL_UP:
825                 case AVRCP_OPERATION_ID_CHANNEL_DOWN:
826                 case AVRCP_OPERATION_ID_SELECT:
827                 case AVRCP_OPERATION_ID_UP:
828                 case AVRCP_OPERATION_ID_DOWN:
829                 case AVRCP_OPERATION_ID_LEFT:
830                 case AVRCP_OPERATION_ID_RIGHT:
831                 case AVRCP_OPERATION_ID_ROOT_MENU:
832                     avrcp_target_operation_accepted(connection->avrcp_cid, packet[6], packet[7], packet[8]);
833                     avrcp_target_emit_operation(avrcp_target_context.avrcp_callback, connection->avrcp_cid, operation_id, packet[7], packet[8]);
834                     break;
835                 case AVRCP_OPERATION_ID_UNDEFINED:
836                     avrcp_target_operation_not_implemented(connection->avrcp_cid, packet[6], packet[7], packet[8]);
837                     return;
838                 default:
839                     avrcp_target_operation_not_implemented(connection->avrcp_cid, packet[6], packet[7], packet[8]);
840                     return;
841             }
842             break;
843         }
844 
845         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
846             pdu_id = pdu[0];
847             // 1 - reserved
848             // 2-3 param length,
849             uint16_t length = big_endian_read_16(pdu, 2);
850             memcpy(connection->cmd_operands, company_id, 3);
851             connection->cmd_operands_length = 3;
852             switch (pdu_id){
853                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:{
854                     if (length == 0){
855                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PLAYER_ID);
856                         break;
857                     }
858                     avrcp_target_response_accept(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_SUCCESS);
859                     break;
860                 }
861                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
862                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) pdu[pos];
863                     switch (capability_id){
864                         case AVRCP_CAPABILITY_ID_EVENT:
865                             avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_EVENT_IDS_QUERY);
866                             break;
867                         case AVRCP_CAPABILITY_ID_COMPANY:
868                             avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_COMPANY_IDS_QUERY);
869                             break;
870                         default:
871                             avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
872                             break;
873                     }
874                     break;
875                 }
876                 case AVRCP_PDU_ID_GET_PLAY_STATUS:
877                     avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_PLAY_STATUS_QUERY);
878                     break;
879                 case AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE:
880                     connection->cmd_operands[0] = pdu[4];
881                     connection->abort_continue_response = 1;
882                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
883                     break;
884                 case AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE:
885                     if (pdu[4] != AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES){
886                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
887                         return;
888                     }
889                     connection->now_playing_info_response = 1;
890                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
891                     break;
892                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
893                     uint8_t play_identifier[8];
894                     memset(play_identifier, 0, 8);
895                     if (memcmp(pdu+pos, play_identifier, 8) != 0) {
896                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
897                         return;
898                     }
899                     pos += 8;
900                     uint8_t attribute_count = pdu[pos++];
901                     // printf("AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES attribute count %d\n", attribute_count);
902                     connection->next_attr_id = AVRCP_MEDIA_ATTR_NONE;
903                     if (!attribute_count){
904                         connection->now_playing_info_attr_bitmap = 0xFE;
905                     } else {
906                         int i;
907                         connection->now_playing_info_attr_bitmap = 0;
908                         for (i=0; i < attribute_count; i++){
909                             uint16_t attr_id = big_endian_read_16(pdu, pos);
910                             pos += 2;
911                             connection->now_playing_info_attr_bitmap |= (1 << attr_id);
912                         }
913                     }
914                     log_info("now_playing_info_attr_bitmap 0x%02x", connection->now_playing_info_attr_bitmap);
915                     avrcp_target_now_playing_info(connection);
916                     break;
917                 }
918                 case AVRCP_PDU_ID_REGISTER_NOTIFICATION:{
919                     // 0 - pdu id
920                     // 1 - reserved
921                     // 2-3 param length
922                     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) pdu[4];
923                     uint16_t event_mask = (1 << event_id);
924 
925                     switch (event_id){
926                         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:
927                             connection->notifications_enabled |= event_mask;
928                             if (connection->track_selected){
929                                 avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_SELECTED, 8);
930                             } else {
931                                 avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_NOT_SELECTED, 8);
932                             }
933                             break;
934                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:
935                             connection->notifications_enabled |= event_mask;
936                             avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, (const uint8_t *)&connection->playback_status, 1);
937                             break;
938                         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:
939                             connection->notifications_enabled |= event_mask;
940                             avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, NULL, 0);
941                             break;
942                         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:
943                             connection->notifications_enabled |= event_mask;
944                             avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, (const uint8_t *)&connection->volume_percentage, 1);
945                             break;
946                         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:
947                             connection->notifications_enabled |= event_mask;
948                             avrcp_target_response_vendor_dependent_interim(connection, subunit_type, subunit_id, opcode, pdu_id, event_id, (const uint8_t *)&connection->battery_status, 1);
949                             break;
950                         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:
951                         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
952                         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:
953                             avrcp_target_response_not_implemented(connection, subunit_type, subunit_id, opcode, pdu_id, event_id);
954                             return;
955                         case AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED:
956                             connection->notifications_enabled |= event_mask;
957                             avrcp_target_response_addressed_player_changed_interim(connection, subunit_type, subunit_id, opcode, pdu_id);
958                             return;
959                         default:
960                             avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
961                             return;
962                     }
963                     break;
964                 }
965                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME: {
966                     if (length != 1){
967                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
968                         break;
969                     }
970 
971                     uint8_t absolute_volume = pdu[4];
972                     if (absolute_volume < 0x80){
973                         connection->volume_percentage = absolute_volume;
974                     }
975                     avrcp_target_response_accept(connection, subunit_type, subunit_id, opcode, pdu_id, connection->volume_percentage);
976                     break;
977                 }
978                 default:
979                     log_info("AVRCP target: unhandled pdu id 0x%02x", pdu_id);
980                     avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
981                     break;
982             }
983             break;
984         default:
985             log_info("AVRCP target: opcode 0x%02x not implemented", avrcp_cmd_opcode(packet,size));
986             break;
987     }
988 }
989 
990 #if 0
991 static int avrcp_target_send_addressed_player_changed_notification(uint16_t cid, avrcp_connection_t * connection, uint16_t uid, uint16_t uid_counter){
992     if (!connection){
993         log_error("avrcp tartget: could not find a connection.");
994         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
995     }
996     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
997     connection->command_type    = AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
998     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
999     connection->subunit_id      = AVRCP_SUBUNIT_ID;
1000 
1001     uint16_t pos = 0;
1002     l2cap_reserve_packet_buffer();
1003     uint8_t * packet = l2cap_get_outgoing_buffer();
1004 
1005     connection->packet_type = AVRCP_SINGLE_PACKET;
1006     packet[pos++] = (connection->transaction_label << 4) | (connection->packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
1007     // Profile IDentifier (PID)
1008     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
1009     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
1010 
1011     // command_type
1012     packet[pos++] = connection->command_type;
1013     // subunit_type | subunit ID
1014     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
1015     // opcode
1016     packet[pos++] = (uint8_t)connection->command_opcode;
1017 
1018     // company id is 3 bytes long
1019     big_endian_store_24(packet, pos, BT_SIG_COMPANY_ID);
1020     pos += 3;
1021 
1022     packet[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
1023     packet[pos++] = 0;
1024     big_endian_store_16(packet, pos, 5);
1025     pos += 2;
1026     packet[pos++] = AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED;
1027     big_endian_store_16(packet, pos, uid);
1028     pos += 2;
1029     big_endian_store_16(packet, pos, uid_counter);
1030     pos += 2;
1031 
1032     connection->wait_to_send = 0;
1033     return l2cap_send_prepared(cid, pos);
1034 }
1035 #endif
1036 
1037 static int avrcp_target_send_notification(uint16_t cid, avrcp_connection_t * connection, uint8_t notification_id, uint8_t * value, uint16_t value_len){
1038     if (!connection){
1039         log_error("avrcp tartget: could not find a connection.");
1040         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1041     }
1042 
1043     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1044     connection->command_type    = AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
1045     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
1046     connection->subunit_id      = AVRCP_SUBUNIT_ID;
1047 
1048     uint16_t pos = 0;
1049     l2cap_reserve_packet_buffer();
1050     uint8_t * packet = l2cap_get_outgoing_buffer();
1051     uint16_t  size   = l2cap_get_remote_mtu_for_local_cid(connection->l2cap_signaling_cid);
1052 
1053     connection->packet_type = AVRCP_SINGLE_PACKET;
1054     packet[pos++] = (connection->transaction_label << 4) | (connection->packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
1055     // Profile IDentifier (PID)
1056     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
1057     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
1058 
1059     // command_type
1060     packet[pos++] = connection->command_type;
1061     // subunit_type | subunit ID
1062     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
1063     // opcode
1064     packet[pos++] = (uint8_t)connection->command_opcode;
1065 
1066     // company id is 3 bytes long
1067     big_endian_store_24(packet, pos, BT_SIG_COMPANY_ID);
1068     pos += 3;
1069 
1070     packet[pos++] = AVRCP_PDU_ID_REGISTER_NOTIFICATION;
1071     packet[pos++] = 0;
1072     uint16_t remainig_outgoing_buffer_size = size > (value_len + 2 + 1) ? size - (value_len + 2 + 1): 0;
1073     uint16_t caped_value_len = value_len > remainig_outgoing_buffer_size ? remainig_outgoing_buffer_size : value_len;
1074     big_endian_store_16(packet, pos, caped_value_len);
1075     pos += 2;
1076     packet[pos++] = notification_id;
1077 
1078     memcpy(packet+pos, value, caped_value_len);
1079     pos += caped_value_len;
1080     connection->wait_to_send = 0;
1081     return l2cap_send_prepared(cid, pos);
1082 }
1083 
1084 static void avrcp_target_reset_notification(avrcp_connection_t * connection, uint8_t notification_id){
1085     if (!connection){
1086         log_error("avrcp tartget: could not find a connection.");
1087         return;
1088     }
1089     connection->notifications_enabled &= ~(1 << notification_id);
1090     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1091 
1092 }
1093 
1094 static void avrcp_target_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1095     avrcp_connection_t * connection;
1096     switch (packet_type) {
1097         case L2CAP_DATA_PACKET:
1098             connection = get_avrcp_connection_for_l2cap_signaling_cid(channel, &avrcp_target_context);
1099             if (!connection) break;
1100             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1101             break;
1102         case HCI_EVENT_PACKET:
1103             switch (hci_event_packet_get_type(packet)){
1104                 case L2CAP_EVENT_CAN_SEND_NOW:{
1105                     connection = get_avrcp_connection_for_l2cap_signaling_cid(channel, &avrcp_target_context);
1106                     if (!connection) {
1107                         log_error("Connection not found\n");
1108                         break;
1109                     }
1110 
1111                     if (connection->abort_continue_response){
1112                         connection->abort_continue_response = 0;
1113                         connection->now_playing_info_response = 0;
1114                         avrcp_target_abort_continue_response(connection->l2cap_signaling_cid, connection);
1115                         break;
1116                     }
1117 
1118                     if (connection->now_playing_info_response){
1119                         connection->now_playing_info_response = 0;
1120                         avrcp_target_send_now_playing_info(connection->l2cap_signaling_cid, connection);
1121                         break;
1122                     }
1123 
1124                     if (connection->track_changed){
1125                         connection->track_changed = 0;
1126                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED, connection->track_id, 8);
1127                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED);
1128                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1129                         break;
1130                     }
1131 
1132                     if (connection->playback_status_changed){
1133                         connection->playback_status_changed = 0;
1134                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED, &connection->playback_status_changed, 1);
1135                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED);
1136                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1137                         break;
1138                     }
1139 
1140                     // if (connection->addressed_player_changed){
1141                     //     connection->playback_status_changed = 0;
1142                     //     avrcp_target_send_addressed_player_changed_notification(connection->l2cap_signaling_cid, connection, connection->addressed_player_id, connection->uid_counter);
1143                     //     avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED);
1144                     //     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1145                     //     break;
1146                     // }
1147 
1148                     if (connection->playing_content_changed){
1149                         connection->playing_content_changed = 0;
1150                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED, NULL, 0);
1151                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED);
1152                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1153                         break;
1154                     }
1155 
1156                     if (connection->battery_status_changed){
1157                         connection->battery_status_changed = 0;
1158                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED, (uint8_t *)&connection->battery_status, 1);
1159                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED);
1160                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1161                         break;
1162                     }
1163 
1164                     if (connection->volume_percentage_changed){
1165                         connection->volume_percentage_changed = 0;
1166                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED, &connection->volume_percentage, 1);
1167                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED);
1168                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1169                         break;
1170                     }
1171 
1172                     switch (connection->state){
1173                         case AVCTP_W2_SEND_RESPONSE:
1174                             connection->state = AVCTP_CONNECTION_OPENED;
1175                             // if (connection->now_playing_info_response){
1176                             //     connection->now_playing_info_response = 0;
1177                             //     avrcp_target_send_now_playing_info(connection->l2cap_signaling_cid, connection);
1178                             //     break;
1179                             // }
1180                             avrcp_target_send_response(connection->l2cap_signaling_cid, connection);
1181                             break;
1182                         default:
1183                             return;
1184                     }
1185                     break;
1186             }
1187             default:
1188                 avrcp_packet_handler(packet_type, channel, packet, size, &avrcp_target_context);
1189                 break;
1190         }
1191         default:
1192             break;
1193     }
1194 }
1195 
1196 void avrcp_target_init(void){
1197     avrcp_target_context.role = AVRCP_TARGET;
1198     avrcp_target_context.connections = NULL;
1199     avrcp_target_context.packet_handler = avrcp_target_packet_handler;
1200     l2cap_register_service(&avrcp_target_packet_handler, BLUETOOTH_PROTOCOL_AVCTP, 0xffff, LEVEL_0);
1201 }
1202 
1203 void avrcp_target_register_packet_handler(btstack_packet_handler_t callback){
1204     if (callback == NULL){
1205         log_error("avrcp_register_packet_handler called with NULL callback");
1206         return;
1207     }
1208     avrcp_target_context.avrcp_callback = callback;
1209 }
1210 
1211 uint8_t avrcp_target_connect(bd_addr_t bd_addr, uint16_t * avrcp_cid){
1212     return avrcp_connect(bd_addr, &avrcp_target_context, avrcp_cid);
1213 }
1214 
1215 uint8_t avrcp_target_disconnect(uint16_t avrcp_cid){
1216     avrcp_connection_t * connection = get_avrcp_connection_for_avrcp_cid(avrcp_cid, &avrcp_target_context);
1217     if (!connection){
1218         log_error("avrcp_get_capabilities: could not find a connection.");
1219         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1220     }
1221     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
1222     l2cap_disconnect(connection->l2cap_signaling_cid, 0);
1223     return ERROR_CODE_SUCCESS;
1224 }
1225 
1226