xref: /btstack/src/classic/avrcp_target.c (revision fda344fc0dd430a9c36aa60bde7e2e326811a122)
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 <string.h>
43 #include <inttypes.h>
44 
45 #include "classic/avrcp.h"
46 #include "classic/avrcp_target.h"
47 
48 #include "bluetooth_sdp.h"
49 #include "btstack_debug.h"
50 #include "btstack_event.h"
51 #include "btstack_util.h"
52 #include "l2cap.h"
53 
54 #define AVRCP_ATTR_HEADER_LEN  8
55 
56 static const uint8_t AVRCP_NOTIFICATION_TRACK_SELECTED[] = {0,0,0,0,0,0,0,0};
57 static const uint8_t AVRCP_NOTIFICATION_TRACK_NOT_SELECTED[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
58 
59 avrcp_context_t avrcp_target_context;
60 
61 static int avrcp_target_supports_browsing(uint16_t target_supported_features){
62     return target_supported_features & AVRCP_FEATURE_MASK_BROWSING;
63 }
64 
65 void avrcp_target_create_sdp_record(uint8_t * service, uint32_t service_record_handle, uint16_t supported_features, const char * service_name, const char * service_provider_name){
66     avrcp_create_sdp_record(0, service, service_record_handle, avrcp_target_supports_browsing(supported_features), supported_features, service_name, service_provider_name);
67 }
68 
69 static void
70 avrcp_target_emit_operation(btstack_packet_handler_t callback, uint16_t avrcp_cid, avrcp_operation_id_t operation_id,
71                             bool button_pressed, uint8_t operands_length, uint8_t operand) {
72     btstack_assert(callback != NULL);
73 
74     uint8_t event[9];
75     int pos = 0;
76     event[pos++] = HCI_EVENT_AVRCP_META;
77     event[pos++] = sizeof(event) - 2;
78     event[pos++] = AVRCP_SUBEVENT_OPERATION;
79     little_endian_store_16(event, pos, avrcp_cid);
80     pos += 2;
81     event[pos++] = operation_id;
82     event[pos++] = button_pressed ? 1 : 0;
83     event[pos++] = operands_length;
84     event[pos++] = operand;
85     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
86 }
87 
88 static void avrcp_target_emit_volume_changed(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t absolute_volume){
89     btstack_assert(callback != NULL);
90 
91     uint8_t event[7];
92     int offset = 0;
93     event[offset++] = HCI_EVENT_AVRCP_META;
94     event[offset++] = sizeof(event) - 2;
95     event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
96     little_endian_store_16(event, offset, avrcp_cid);
97     offset += 2;
98     event[offset++] = AVRCP_CTYPE_NOTIFY;
99     event[offset++] = absolute_volume;
100     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
101 }
102 
103 static void avrcp_target_emit_respond_vendor_dependent_query(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t subevent_id){
104     btstack_assert(callback != NULL);
105 
106     uint8_t event[5];
107     int pos = 0;
108     event[pos++] = HCI_EVENT_AVRCP_META;
109     event[pos++] = sizeof(event) - 2;
110     event[pos++] = subevent_id;
111     little_endian_store_16(event, pos, avrcp_cid);
112     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
113 }
114 
115 // returns number of bytes stored
116 static uint16_t avrcp_target_pack_single_element_header(uint8_t * packet, uint16_t pos, avrcp_media_attribute_id_t attr_id, uint16_t attr_value_size){
117     btstack_assert(attr_id >= 1);
118     btstack_assert(attr_id <= AVRCP_MEDIA_ATTR_COUNT);
119 
120     big_endian_store_32(packet, pos, attr_id);
121     big_endian_store_16(packet, pos+4, RFC2978_CHARSET_MIB_UTF8);
122     big_endian_store_16(packet, pos+6, attr_value_size);
123     return 8;
124 }
125 
126 // returns number of bytes stored
127 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){
128     uint16_t attr_value_length = sprintf((char *)(packet+pos+8), "%0" PRIu32, value);
129     (void) avrcp_target_pack_single_element_header(packet, pos, attr_id, attr_value_length);
130     return 8 + attr_value_length;
131 }
132 
133 // returns number of bytes stored
134 static uint16_t avrcp_target_pack_single_element_attribute_string_fragment(uint8_t * packet, uint16_t pos, avrcp_media_attribute_id_t attr_id, uint8_t * attr_value, uint16_t attr_value_to_copy, uint16_t attr_value_size, bool header){
135     if (attr_value_size == 0) return 0;
136     uint16_t bytes_stored = 0;
137     if (header){
138         bytes_stored += avrcp_target_pack_single_element_header(packet, pos, attr_id, attr_value_size);
139     }
140     (void)memcpy(packet + pos + bytes_stored, attr_value, attr_value_to_copy);
141     bytes_stored += attr_value_to_copy;
142     return bytes_stored;
143 }
144 
145 static int avrcp_target_abort_continue_response(uint16_t cid, avrcp_connection_t * connection){
146     uint16_t pos = 0;
147     l2cap_reserve_packet_buffer();
148     uint8_t * packet = l2cap_get_outgoing_buffer();
149 
150     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
151     connection->command_type    = AVRCP_CTYPE_RESPONSE_ACCEPTED;
152     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
153     connection->subunit_id      = AVRCP_SUBUNIT_ID;
154 
155     packet[pos++] = (connection->transaction_id << 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_REQUEST_ABORT_CONTINUING_RESPONSE;
172 
173     // reserve byte for packet type
174     packet[pos++] = AVRCP_SINGLE_PACKET;
175     big_endian_store_16(packet, pos, 0);
176     pos += 2;
177     return l2cap_send_prepared(cid, pos);
178 }
179 
180 static int avrcp_target_send_now_playing_info(uint16_t cid, avrcp_connection_t * connection){
181     uint16_t pos = 0;
182     l2cap_reserve_packet_buffer();
183     uint8_t * packet = l2cap_get_outgoing_buffer();
184     uint16_t  size   = l2cap_get_remote_mtu_for_local_cid(connection->l2cap_signaling_cid);
185 
186     packet[pos++] = (connection->transaction_id << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
187     // Profile IDentifier (PID)
188     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
189     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
190 
191     // command_type
192     packet[pos++] = connection->command_type;
193     // subunit_type | subunit ID
194     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
195     // opcode
196     packet[pos++] = (uint8_t)connection->command_opcode;
197 
198     // company id is 3 bytes long
199     big_endian_store_24(packet, pos, BT_SIG_COMPANY_ID);
200     pos += 3;
201 
202     packet[pos++] = AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES;
203 
204     // reserve byte for packet type
205     uint8_t pos_packet_type = pos;
206     pos++;
207 
208     uint16_t playing_info_buffer_len_position = pos;
209     pos += 2;
210     if (connection->next_attr_id == AVRCP_MEDIA_ATTR_NONE){
211         packet[pos_packet_type] = AVRCP_SINGLE_PACKET;
212         connection->packet_type = AVRCP_SINGLE_PACKET;
213         packet[pos++] = count_set_bits_uint32(connection->now_playing_info_attr_bitmap);
214         connection->next_attr_id = AVRCP_MEDIA_ATTR_ALL;
215     }
216 
217     uint8_t fragmented = 0;
218     int num_free_bytes = size - pos - 2;
219     uint8_t MAX_NUMBER_ATTR_LEN = 10;
220 
221     while (!fragmented && (num_free_bytes > 0) && (connection->next_attr_id <= AVRCP_MEDIA_ATTR_SONG_LENGTH_MS)){
222         avrcp_media_attribute_id_t attr_id = connection->next_attr_id;
223         int attr_index = attr_id - 1;
224 
225         if (connection->now_playing_info_attr_bitmap & (1 << attr_id)){
226             int num_written_bytes = 0;
227             int num_bytes_to_write = 0;
228             switch (attr_id){
229                 case AVRCP_MEDIA_ATTR_ALL:
230                 case AVRCP_MEDIA_ATTR_NONE:
231                     break;
232                 case AVRCP_MEDIA_ATTR_TRACK:
233                     num_bytes_to_write = AVRCP_ATTR_HEADER_LEN + MAX_NUMBER_ATTR_LEN;
234                     if (num_free_bytes >= num_bytes_to_write){
235                         num_written_bytes = avrcp_target_pack_single_element_attribute_number(packet, pos, attr_id, connection->track_nr);
236                         break;
237                     }
238                     fragmented = 1;
239                     connection->attribute_value_offset = 0;
240                     break;
241                 case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
242                     num_bytes_to_write = AVRCP_ATTR_HEADER_LEN + MAX_NUMBER_ATTR_LEN;
243                     if (num_free_bytes >= num_bytes_to_write){
244                         num_written_bytes = avrcp_target_pack_single_element_attribute_number(packet, pos, attr_id, connection->total_tracks);
245                         break;
246                     }
247                     fragmented = 1;
248                     connection->attribute_value_offset = 0;
249                     break;
250                 case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
251                     num_bytes_to_write = AVRCP_ATTR_HEADER_LEN + MAX_NUMBER_ATTR_LEN;
252                     if (num_free_bytes >= num_bytes_to_write){
253                         num_written_bytes = avrcp_target_pack_single_element_attribute_number(packet, pos, attr_id, connection->song_length_ms);
254                         break;
255                     }
256                     fragmented = 1;
257                     connection->attribute_value_offset = 0;
258                     break;
259                 default:{
260                     bool      header = connection->attribute_value_offset == 0;
261                     uint8_t * attr_value =     (uint8_t *) (connection->now_playing_info[attr_index].value + connection->attribute_value_offset);
262                     uint16_t  attr_value_len = connection->now_playing_info[attr_index].len - connection->attribute_value_offset;
263 
264                     num_bytes_to_write = attr_value_len + (header * AVRCP_ATTR_HEADER_LEN);
265                     if (num_bytes_to_write <= num_free_bytes){
266                         connection->attribute_value_offset = 0;
267                         num_written_bytes = num_bytes_to_write;
268                         avrcp_target_pack_single_element_attribute_string_fragment(packet, pos, attr_id, attr_value, attr_value_len, connection->now_playing_info[attr_index].len, header);
269                         break;
270                     }
271                     fragmented = 1;
272                     num_written_bytes = num_free_bytes;
273                     attr_value_len = num_free_bytes - (header * AVRCP_ATTR_HEADER_LEN);
274                     avrcp_target_pack_single_element_attribute_string_fragment(packet, pos, attr_id, attr_value, attr_value_len, connection->now_playing_info[attr_index].len, header);
275                     connection->attribute_value_offset += attr_value_len;
276                     break;
277                 }
278             }
279             pos += num_written_bytes;
280             num_free_bytes -= num_written_bytes;
281         }
282         if (!fragmented){
283             // C++ compatible version of connection->next_attr_id++
284             connection->next_attr_id = (avrcp_media_attribute_id_t) (((int) connection->next_attr_id) + 1);
285         }
286     }
287 
288     if (fragmented){
289         switch (connection->packet_type){
290             case AVRCP_SINGLE_PACKET:
291                 connection->packet_type = AVRCP_START_PACKET;
292                 break;
293             default:
294                 connection->packet_type = AVRCP_CONTINUE_PACKET;
295                 break;
296         }
297     } else {
298         if (connection->next_attr_id >= AVRCP_MEDIA_ATTR_SONG_LENGTH_MS){ // DONE
299             if (connection->packet_type != AVRCP_SINGLE_PACKET){
300                 connection->packet_type = AVRCP_END_PACKET;
301             }
302         }
303     }
304     packet[pos_packet_type] = connection->packet_type;
305     // store attr value length
306     big_endian_store_16(packet, playing_info_buffer_len_position, pos - playing_info_buffer_len_position - 2);
307     return l2cap_send_prepared(cid, size);
308 }
309 
310 
311 
312 static int avrcp_target_send_response(uint16_t cid, avrcp_connection_t * connection){
313     int pos = 0;
314     l2cap_reserve_packet_buffer();
315     uint8_t * packet = l2cap_get_outgoing_buffer();
316 
317     // transport header
318     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
319 
320     // TODO: check for fragmentation
321     connection->packet_type = AVRCP_SINGLE_PACKET;
322 
323     packet[pos++] = (connection->transaction_id << 4) | (connection->packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
324     // Profile IDentifier (PID)
325     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
326     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
327     // command_type
328     packet[pos++] = connection->command_type;
329     // subunit_type | subunit ID
330     packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
331     // opcode
332     packet[pos++] = (uint8_t)connection->command_opcode;
333 
334     (void)memcpy(packet + pos, connection->cmd_operands,
335                  connection->cmd_operands_length);
336     pos += connection->cmd_operands_length;
337 
338     return l2cap_send_prepared(cid, pos);
339 }
340 
341 static void avrcp_target_response_setup(avrcp_connection_t * connection, avrcp_command_type_t command_type, avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id,
342                                         avrcp_command_opcode_t opcode){
343     connection->command_type = command_type;
344     connection->subunit_type = subunit_type;
345     connection->subunit_id =   subunit_id;
346     connection->command_opcode = opcode;
347 }
348 
349 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, uint8_t status){
350     // AVRCP_CTYPE_RESPONSE_REJECTED
351     avrcp_target_response_setup(connection, AVRCP_CTYPE_RESPONSE_ACCEPTED, subunit_type, subunit_id, opcode);
352     // company id is 3 bytes long
353     int pos = connection->cmd_operands_length;
354     connection->cmd_operands[pos++] = pdu_id;
355     connection->cmd_operands[pos++] = 0;
356     // param length
357     big_endian_store_16(connection->cmd_operands, pos, 1);
358     pos += 2;
359     connection->cmd_operands[pos++] = status;
360     connection->cmd_operands_length = pos;
361     connection->accept_response = 1;
362     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
363     return ERROR_CODE_SUCCESS;
364 }
365 
366 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){
367     // AVRCP_CTYPE_RESPONSE_REJECTED
368     avrcp_target_response_setup(connection, AVRCP_CTYPE_RESPONSE_REJECTED, subunit_type, subunit_id, opcode);
369     // company id is 3 bytes long
370     int pos = connection->cmd_operands_length;
371     connection->cmd_operands[pos++] = pdu_id;
372     connection->cmd_operands[pos++] = 0;
373     // param length
374     big_endian_store_16(connection->cmd_operands, pos, 1);
375     pos += 2;
376     connection->cmd_operands[pos++] = status;
377     connection->cmd_operands_length = pos;
378     connection->state = AVCTP_W2_SEND_RESPONSE;
379     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
380     return ERROR_CODE_SUCCESS;
381 }
382 
383 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){
384     avrcp_target_response_setup(connection, AVRCP_CTYPE_RESPONSE_NOT_IMPLEMENTED, subunit_type, subunit_id, opcode);
385     // company id is 3 bytes long
386     int pos = connection->cmd_operands_length;
387     connection->cmd_operands[pos++] = pdu_id;
388     connection->cmd_operands[pos++] = 0;
389     // param length
390     big_endian_store_16(connection->cmd_operands, pos, 1);
391     pos += 2;
392     connection->cmd_operands[pos++] = event_id;
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_vendor_dependent_interim(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, uint8_t event_id, const uint8_t * value, uint16_t value_len){
401 
402     // company id is 3 bytes long
403     int pos = connection->cmd_operands_length;
404     connection->cmd_operands[pos++] = pdu_id;
405     connection->cmd_operands[pos++] = 0;
406     // param length
407     big_endian_store_16(connection->cmd_operands, pos, 1 + value_len);
408     pos += 2;
409     connection->cmd_operands[pos++] = event_id;
410     if (value && (value_len > 0)){
411         (void)memcpy(connection->cmd_operands + pos, value, value_len);
412         pos += value_len;
413     }
414     connection->cmd_operands_length = pos;
415     connection->state = AVCTP_W2_SEND_RESPONSE;
416     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
417     return ERROR_CODE_SUCCESS;
418 }
419 
420 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){
421     avrcp_target_response_setup(connection, AVRCP_CTYPE_RESPONSE_INTERIM, subunit_type, subunit_id, opcode);
422 
423     // company id is 3 bytes long
424     int pos = connection->cmd_operands_length;
425     connection->cmd_operands[pos++] = pdu_id;
426     connection->cmd_operands[pos++] = 0;
427     // param length
428     big_endian_store_16(connection->cmd_operands, pos, 5);
429     pos += 2;
430     connection->cmd_operands[pos++] = AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED;
431     big_endian_read_16( &connection->cmd_operands[pos], connection->addressed_player_id);
432     pos += 2;
433     big_endian_read_16( &connection->cmd_operands[pos], connection->uid_counter);
434     pos += 2;
435 
436     connection->cmd_operands_length = pos;
437     connection->state = AVCTP_W2_SEND_RESPONSE;
438     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
439     return ERROR_CODE_SUCCESS;
440 }
441 
442 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){
443     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
444     if (!connection){
445         log_error("Could not find a connection.");
446         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
447     }
448     avrcp_target_response_setup(connection, cmd_type, AVRCP_SUBUNIT_TYPE_PANEL, AVRCP_SUBUNIT_ID, AVRCP_CMD_OPCODE_PASS_THROUGH);
449 
450     int pos = 0;
451     connection->cmd_operands[pos++] = opid;
452     connection->cmd_operands[pos++] = operands_length;
453     if (operands_length == 1){
454         connection->cmd_operands[pos++] = operand;
455     }
456     connection->cmd_operands_length = pos;
457 
458     connection->state = AVCTP_W2_SEND_RESPONSE;
459     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
460     return ERROR_CODE_SUCCESS;
461 }
462 
463 uint8_t avrcp_target_operation_rejected(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
464     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_REJECTED, opid, operands_length, operand);
465 }
466 
467 uint8_t avrcp_target_operation_accepted(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
468     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_ACCEPTED, opid, operands_length, operand);
469 }
470 
471 uint8_t avrcp_target_operation_not_implemented(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_ACCEPTED, opid, operands_length, operand);
473 }
474 
475 void avrcp_target_set_unit_info(uint16_t avrcp_cid, avrcp_subunit_type_t unit_type, uint32_t company_id){
476     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
477     if (!connection){
478         log_error("avrcp_target_set_unit_info: could not find a connection.");
479         return;
480     }
481     connection->unit_type = unit_type;
482     connection->company_id = company_id;
483 }
484 
485 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){
486     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
487     if (!connection){
488         log_error("avrcp_target_set_subunit_info: could not find a connection.");
489         return;
490     }
491     connection->subunit_info_type = subunit_type;
492     connection->subunit_info_data = subunit_info_data;
493     connection->subunit_info_data_size = subunit_info_data_size;
494 }
495 
496 static uint8_t avrcp_target_unit_info(avrcp_connection_t * connection){
497     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
498 
499     uint8_t unit = 0;
500     connection->command_type = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
501     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
502     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
503     connection->command_opcode = AVRCP_CMD_OPCODE_UNIT_INFO;
504 
505     connection->cmd_operands_length = 5;
506     connection->cmd_operands[0] = 0x07;
507     connection->cmd_operands[1] = (connection->unit_type << 4) | unit;
508     // company id is 3 bytes long
509     big_endian_store_32(connection->cmd_operands, 2, connection->company_id);
510 
511     connection->state = AVCTP_W2_SEND_RESPONSE;
512     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
513     return ERROR_CODE_SUCCESS;
514 }
515 
516 
517 static uint8_t avrcp_target_subunit_info(avrcp_connection_t * connection, uint8_t offset){
518     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
519     if (offset >= 32) return AVRCP_STATUS_INVALID_PARAMETER;
520 
521     connection->command_opcode = AVRCP_CMD_OPCODE_SUBUNIT_INFO;
522     connection->command_type = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
523     connection->subunit_type = AVRCP_SUBUNIT_TYPE_UNIT; //vendor unique
524     connection->subunit_id =   AVRCP_SUBUNIT_ID_IGNORE;
525 
526     uint8_t page = offset / 4;
527     uint8_t extension_code = 7;
528     connection->cmd_operands_length = 5;
529     connection->cmd_operands[0] = (page << 4) | extension_code;
530 
531     // mark non-existant entry with 0xff
532     memset(&connection->cmd_operands[1], 0xff, 4);
533     if ((connection->subunit_info_data != NULL) && (offset < connection->subunit_info_data_size)){
534         uint8_t bytes_to_copy = btstack_min(connection->subunit_info_data_size - offset, 4);
535         memcpy(&connection->cmd_operands[1], &connection->subunit_info_data[offset], bytes_to_copy);
536     }
537 
538     connection->state = AVCTP_W2_SEND_RESPONSE;
539     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
540     return ERROR_CODE_SUCCESS;
541 }
542 
543 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){
544     *out_connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
545     if (!*out_connection){
546         log_error("avrcp tartget: could not find a connection.");
547         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
548     }
549 
550     if ((*out_connection)->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
551     (*out_connection)->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
552     (*out_connection)->command_type    = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
553     (*out_connection)->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
554     (*out_connection)->subunit_id      = AVRCP_SUBUNIT_ID;
555 
556     (*out_connection)->cmd_operands[(*out_connection)->cmd_operands_length++] = pdu_id;
557     // reserved
558     (*out_connection)->cmd_operands[(*out_connection)->cmd_operands_length++] = 0;
559     // param length
560     big_endian_store_16((*out_connection)->cmd_operands, (*out_connection)->cmd_operands_length, param_length);
561     (*out_connection)->cmd_operands_length += 2;
562     return ERROR_CODE_SUCCESS;
563 }
564 
565 static uint8_t avrcp_target_capability(uint16_t avrcp_cid, avrcp_capability_id_t capability_id, uint8_t num_capabilities, const uint8_t *capabilities, uint8_t capabilities_size){
566     avrcp_connection_t * connection = NULL;
567     uint8_t status = avrcp_prepare_vendor_dependent_response(avrcp_cid, &connection, AVRCP_PDU_ID_GET_CAPABILITIES, 2 + capabilities_size);
568     if (status != ERROR_CODE_SUCCESS) return status;
569 
570     connection->cmd_operands[connection->cmd_operands_length++] = capability_id;
571     connection->cmd_operands[connection->cmd_operands_length++] = num_capabilities;
572     (void)memcpy(connection->cmd_operands + connection->cmd_operands_length,
573                  capabilities, capabilities_size);
574     connection->cmd_operands_length += capabilities_size;
575 
576     connection->state = AVCTP_W2_SEND_RESPONSE;
577     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
578     return ERROR_CODE_SUCCESS;
579 }
580 
581 uint8_t avrcp_target_supported_events(uint16_t avrcp_cid, uint8_t num_event_ids, const uint8_t *event_ids, uint8_t event_ids_size){
582     return avrcp_target_capability(avrcp_cid, AVRCP_CAPABILITY_ID_EVENT, num_event_ids, event_ids, event_ids_size);
583 }
584 
585 uint8_t avrcp_target_supported_companies(uint16_t avrcp_cid, uint8_t num_company_ids, const uint8_t *company_ids, uint8_t company_ids_size){
586     return avrcp_target_capability(avrcp_cid, AVRCP_CAPABILITY_ID_COMPANY, num_company_ids, company_ids, company_ids_size);
587 }
588 
589 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){
590     avrcp_connection_t * connection = NULL;
591     uint8_t status = avrcp_prepare_vendor_dependent_response(avrcp_cid, &connection, AVRCP_PDU_ID_GET_PLAY_STATUS, 11);
592     if (status != ERROR_CODE_SUCCESS) return status;
593 
594     big_endian_store_32(connection->cmd_operands, connection->cmd_operands_length, song_length_ms);
595     connection->cmd_operands_length += 4;
596     big_endian_store_32(connection->cmd_operands, connection->cmd_operands_length, song_position_ms);
597     connection->cmd_operands_length += 4;
598     connection->cmd_operands[connection->cmd_operands_length++] = play_status;
599 
600     connection->state = AVCTP_W2_SEND_RESPONSE;
601     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
602     return ERROR_CODE_SUCCESS;
603 }
604 
605 static uint8_t avrcp_target_now_playing_info(avrcp_connection_t * connection){
606     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
607     connection->now_playing_info_response = 1;
608     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
609     connection->command_type    = AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE;
610     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
611     connection->subunit_id      = AVRCP_SUBUNIT_ID;
612 
613     connection->state = AVCTP_W2_SEND_RESPONSE;
614     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
615     return ERROR_CODE_SUCCESS;
616 }
617 
618 static uint8_t avrcp_target_store_media_attr(avrcp_connection_t * connection, avrcp_media_attribute_id_t attr_id, const char * value){
619     int index = attr_id - 1;
620     if (!value) return AVRCP_STATUS_INVALID_PARAMETER;
621     connection->now_playing_info[index].value = (uint8_t*)value;
622     connection->now_playing_info[index].len   = strlen(value);
623     return ERROR_CODE_SUCCESS;
624 }
625 
626 uint8_t avrcp_target_set_playback_status(uint16_t avrcp_cid, avrcp_playback_status_t playback_status){
627     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
628     if (!connection){
629         log_error("avrcp_unit_info: could not find a connection.");
630         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
631     }
632     if (connection->playback_status == playback_status) return ERROR_CODE_SUCCESS;
633 
634     connection->playback_status = playback_status;
635     connection->playback_status_changed = 1;
636     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
637     return ERROR_CODE_SUCCESS;
638 }
639 
640 void avrcp_target_set_now_playing_info(uint16_t avrcp_cid, const avrcp_track_t * current_track, uint16_t total_tracks){
641     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
642     if (!connection){
643         log_error("avrcp_unit_info: could not find a connection. cid 0x%02x\n", avrcp_cid);
644         return;
645     }
646     if (!current_track){
647         connection->track_selected = 0;
648         connection->playback_status = AVRCP_PLAYBACK_STATUS_ERROR;
649         return;
650     }
651     (void)memcpy(connection->track_id, current_track->track_id, 8);
652     connection->song_length_ms = current_track->song_length_ms;
653     connection->track_nr = current_track->track_nr;
654     connection->total_tracks = total_tracks;
655     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_TITLE, current_track->title);
656     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ARTIST, current_track->artist);
657     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ALBUM, current_track->album);
658     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_GENRE, current_track->genre);
659     connection->track_selected = 1;
660 
661     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED)) {
662         connection->track_changed = 1;
663         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
664     }
665     return;
666 }
667 
668 uint8_t avrcp_target_track_changed(uint16_t avrcp_cid, uint8_t * track_id){
669     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
670     if (!connection){
671         log_error("avrcp_target_track_changed: could not find connection.");
672         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
673     }
674     if (!track_id) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
675 
676     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED)) {
677         connection->track_changed = 1;
678         (void)memcpy(connection->track_id, track_id, 8);
679         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
680     }
681     return ERROR_CODE_SUCCESS;
682 }
683 
684 uint8_t avrcp_target_playing_content_changed(uint16_t avrcp_cid){
685     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
686     if (!connection){
687         log_error("avrcp_target_playing_content_changed: could not find a connection.");
688         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
689     }
690     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED)) {
691         connection->playing_content_changed = 1;
692         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
693     }
694     return ERROR_CODE_SUCCESS;
695 }
696 
697 uint8_t avrcp_target_addressed_player_changed(uint16_t avrcp_cid, uint16_t player_id, uint16_t uid_counter){
698     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
699     if (!connection){
700         log_error("avrcp_unit_info: could not find a connection.");
701         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
702     }
703     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED)) {
704         connection->uid_counter = uid_counter;
705         connection->addressed_player_id = player_id;
706     }
707     return ERROR_CODE_SUCCESS;
708 }
709 
710 uint8_t avrcp_target_battery_status_changed(uint16_t avrcp_cid, avrcp_battery_status_t battery_status){
711     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
712     if (!connection){
713         log_error("avrcp_unit_info: could not find a connection.");
714         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
715     }
716     if (connection->battery_status == battery_status) return ERROR_CODE_SUCCESS;
717     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED)) {
718         connection->battery_status = battery_status;
719         connection->battery_status_changed = 1;
720         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
721     }
722     return ERROR_CODE_SUCCESS;
723 }
724 
725 uint8_t avrcp_target_volume_changed(uint16_t avrcp_cid, uint8_t volume_percentage){
726     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
727     if (!connection){
728         log_error("avrcp_unit_info: could not find a connection.");
729         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
730     }
731     connection->volume_percentage = volume_percentage;
732     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED )) {
733         connection->notify_volume_percentage_changed = 1;
734         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
735     }
736     return ERROR_CODE_SUCCESS;
737 }
738 
739 static void avrcp_target_set_transaction_label_for_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t notification, uint8_t transaction_label){
740     if (notification > AVRCP_NOTIFICATION_EVENT_MAX_VALUE) return;
741     connection->notifications_transaction_label[notification] = transaction_label;
742 }
743 
744 static uint8_t avrcp_target_get_transaction_label_for_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t notification){
745     if (notification > AVRCP_NOTIFICATION_EVENT_MAX_VALUE) return 0;
746     return connection->notifications_transaction_label[notification];
747 }
748 
749 static bool avcrp_operation_id_is_valid(avrcp_operation_id_t operation_id){
750     if (operation_id < AVRCP_OPERATION_ID_RESERVED_1) return true;
751 
752     if (operation_id < AVRCP_OPERATION_ID_0) return false;
753     if (operation_id < AVRCP_OPERATION_ID_RESERVED_2) return true;
754 
755     if (operation_id < AVRCP_OPERATION_ID_CHANNEL_UP) return false;
756     if (operation_id < AVRCP_OPERATION_ID_RESERVED_3) return true;
757 
758     if (operation_id < AVRCP_OPERATION_ID_CHANNEL_UP) return false;
759     if (operation_id < AVRCP_OPERATION_ID_RESERVED_3) return true;
760 
761     if (operation_id < AVRCP_OPERATION_ID_SKIP) return false;
762     if (operation_id == AVRCP_OPERATION_ID_SKIP) return true;
763 
764     if (operation_id < AVRCP_OPERATION_ID_POWER) return false;
765     if (operation_id < AVRCP_OPERATION_ID_RESERVED_4) return true;
766 
767     if (operation_id < AVRCP_OPERATION_ID_ANGLE) return false;
768     if (operation_id < AVRCP_OPERATION_ID_RESERVED_5) return true;
769 
770     if (operation_id < AVRCP_OPERATION_ID_F1) return false;
771     if (operation_id < AVRCP_OPERATION_ID_RESERVED_6) return true;
772 
773     return false;
774 }
775 
776 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t *packet, uint16_t size){
777 
778     if (size < 6u) return;
779 
780     uint16_t pid = 0;
781     uint8_t transport_header = packet[0];
782     connection->transaction_id = transport_header >> 4;
783 
784     avrcp_packet_type_t packet_type = (avrcp_packet_type_t) ((transport_header & 0x0F) >> 2);
785     switch (packet_type){
786         case AVRCP_SINGLE_PACKET:
787             pid =  big_endian_read_16(packet, 1);
788             break;
789         case AVRCP_START_PACKET:
790             pid =  big_endian_read_16(packet, 2);
791             break;
792         default:
793             break;
794     }
795 
796     switch (packet_type){
797         case AVRCP_SINGLE_PACKET:
798         case AVRCP_START_PACKET:
799             if (pid != BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL){
800                 log_info("Invalid pid 0x%02x, expected 0x%02x", connection->invalid_pid, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
801                 connection->reject_transport_header = 1;
802                 connection->invalid_pid = pid;
803                 connection->transport_header = (connection->transaction_id << 4) | (AVRCP_SINGLE_PACKET << 2 ) | (AVRCP_RESPONSE_FRAME << 1) | 1;
804                 connection->state = AVCTP_W2_SEND_RESPONSE;
805                 avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
806                 return;
807             }
808             break;
809         default:
810             break;
811     }
812 
813     if (packet_type != AVRCP_SINGLE_PACKET) return;
814 
815     avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (packet[4] >> 3);
816     avrcp_subunit_id_t   subunit_id   = (avrcp_subunit_id_t) (packet[4] & 0x07);
817 
818     avrcp_command_opcode_t opcode = (avrcp_command_opcode_t) avrcp_cmd_opcode(packet,size);
819 
820     int pos = 6;
821     uint16_t length;
822     avrcp_pdu_id_t   pdu_id;
823     connection->cmd_operands_length = 0;
824     uint8_t offset;
825     uint8_t operand;
826     avrcp_operation_id_t operation_id;
827 
828     switch (opcode){
829         case AVRCP_CMD_OPCODE_UNIT_INFO:
830             avrcp_target_unit_info(connection);
831             break;
832         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:
833             if ((size - pos) < 3) return;
834             // page: packet[pos] >> 4,
835             offset =  4 * (packet[pos]>>4);
836             // extension code (fixed 7) = packet[pos] & 0x0F
837             // 4 bytes paga data, all 0xFF
838             avrcp_target_subunit_info(connection, offset);
839             break;
840 
841         case AVRCP_CMD_OPCODE_PASS_THROUGH:
842             if (size < 8) return;
843             log_info("AVRCP_OPERATION_ID 0x%02x, operands length %d", packet[6], packet[7]);
844             operation_id = (avrcp_operation_id_t) (packet[6] & 0x7f);
845             operand = 0;
846             if ((packet[7] >= 1) && (size >= 9)){
847                 operand = packet[8];
848             }
849 
850             if (avcrp_operation_id_is_valid(operation_id)){
851                 bool button_pressed = (packet[6] & 0x80) == 0;
852 
853                 avrcp_target_operation_accepted(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], operand);
854                 avrcp_target_emit_operation(avrcp_target_context.avrcp_callback, connection->avrcp_cid,
855                                                 operation_id, button_pressed, packet[7], operand);
856             } else {
857                 avrcp_target_operation_not_implemented(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], operand);
858             }
859             break;
860 
861 
862         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
863 
864             if (size < 13) return;
865 
866             // pos = 6 - company id
867             (void)memcpy(connection->cmd_operands, &packet[pos], 3);
868             connection->cmd_operands_length = 3;
869             pos += 3;
870             // pos = 9
871             pdu_id = (avrcp_pdu_id_t) packet[pos++];
872             // 1 - reserved
873             pos++;
874             // 2-3 param length,
875             length = big_endian_read_16(packet, pos);
876             pos += 2;
877             // pos = 13
878             switch (pdu_id){
879                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:{
880                     if ((pos + 2) > size) return;
881                     bool ok = length == 4;
882                     if (avrcp_target_context.set_addressed_player_callback != NULL){
883                         uint16_t player_id = big_endian_read_16(packet, pos);
884                         ok = avrcp_target_context.set_addressed_player_callback(player_id);
885                     }
886                     if (ok){
887                         avrcp_target_response_accept(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_SUCCESS);
888                     } else {
889                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PLAYER_ID);
890                     }
891                     break;
892                 }
893                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
894                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos];
895                     switch (capability_id){
896                         case AVRCP_CAPABILITY_ID_EVENT:
897                             avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_EVENT_IDS_QUERY);
898                             break;
899                         case AVRCP_CAPABILITY_ID_COMPANY:
900                             avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_COMPANY_IDS_QUERY);
901                             break;
902                         default:
903                             avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
904                             break;
905                     }
906                     break;
907                 }
908                 case AVRCP_PDU_ID_GET_PLAY_STATUS:
909                     avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_PLAY_STATUS_QUERY);
910                     break;
911                 case AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE:
912                     if ((pos + 1) > size) return;
913                     connection->cmd_operands[0] = packet[pos];
914                     connection->abort_continue_response = 1;
915                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
916                     break;
917                 case AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE:
918                     if ((pos + 1) > size) return;
919                     if (packet[pos] != AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES){
920                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
921                         return;
922                     }
923                     connection->now_playing_info_response = 1;
924                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
925                     break;
926                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
927                     if ((pos + 9) > size) return;
928                     uint8_t play_identifier[8];
929                     memset(play_identifier, 0, 8);
930                     if (memcmp(&packet[pos], play_identifier, 8) != 0) {
931                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
932                         return;
933                     }
934                     pos += 8;
935                     uint8_t attribute_count = packet[pos++];
936                     connection->next_attr_id = AVRCP_MEDIA_ATTR_NONE;
937                     if (!attribute_count){
938                         connection->now_playing_info_attr_bitmap = 0xFE;
939                     } else {
940                         int i;
941                         connection->now_playing_info_attr_bitmap = 0;
942                         if ((pos + attribute_count * 2) > size) return;
943                         for (i=0; i < attribute_count; i++){
944                             uint16_t attr_id = big_endian_read_16(packet, pos);
945                             pos += 2;
946                             connection->now_playing_info_attr_bitmap |= (1 << attr_id);
947                         }
948                     }
949                     log_info("now_playing_info_attr_bitmap 0x%02x", connection->now_playing_info_attr_bitmap);
950                     avrcp_target_now_playing_info(connection);
951                     break;
952                 }
953                 case AVRCP_PDU_ID_REGISTER_NOTIFICATION:{
954                     if ((pos + 1) > size) return;
955                     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) packet[pos];
956                     uint16_t event_mask = (1 << event_id);
957                     avrcp_target_set_transaction_label_for_notification(connection, event_id, connection->transaction_id);
958 
959                     switch (event_id){
960                         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:
961                             connection->notifications_enabled |= event_mask;
962                             avrcp_target_response_setup(connection, AVRCP_CTYPE_RESPONSE_INTERIM, subunit_type, subunit_id, opcode);
963                             if (connection->track_selected){
964                                 avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_SELECTED, 8);
965                             } else {
966                                 avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_NOT_SELECTED, 8);
967                             }
968                             break;
969                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:
970                             connection->notifications_enabled |= event_mask;
971                             avrcp_target_response_setup(connection, AVRCP_CTYPE_RESPONSE_INTERIM, subunit_type, subunit_id, opcode);
972                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, (const uint8_t *)&connection->playback_status, 1);
973                             break;
974                         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:
975                             connection->notifications_enabled |= event_mask;
976                             avrcp_target_response_setup(connection, AVRCP_CTYPE_RESPONSE_INTERIM, subunit_type, subunit_id, opcode);
977                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, NULL, 0);
978                             break;
979                         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:
980                             connection->notify_volume_percentage_changed = 0;
981                             connection->notifications_enabled |= event_mask;
982                             avrcp_target_response_setup(connection, AVRCP_CTYPE_RESPONSE_INTERIM, subunit_type, subunit_id, opcode);
983                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, (const uint8_t *)&connection->volume_percentage, 1);
984                             break;
985                         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:
986                             connection->notifications_enabled |= event_mask;
987                             avrcp_target_response_setup(connection, AVRCP_CTYPE_RESPONSE_INTERIM, subunit_type, subunit_id, opcode);
988                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, (const uint8_t *)&connection->battery_status, 1);
989                             break;
990                         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:
991                         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
992                         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:
993                             avrcp_target_response_not_implemented(connection, subunit_type, subunit_id, opcode, pdu_id, event_id);
994                             return;
995                         case AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED:
996                             connection->notifications_enabled |= event_mask;
997                             avrcp_target_response_addressed_player_changed_interim(connection, subunit_type, subunit_id, opcode, pdu_id);
998                             return;
999                         default:
1000                             avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
1001                             return;
1002                     }
1003                     break;
1004                 }
1005                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME: {
1006                     if (length != 1){
1007                         avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
1008                         break;
1009                     }
1010 
1011                     if ((pos + 1) > size) return;
1012                     uint8_t absolute_volume = packet[pos];
1013                     if (absolute_volume < 0x80){
1014                         connection->volume_percentage = absolute_volume;
1015                     }
1016                     avrcp_target_response_accept(connection, subunit_type, subunit_id, opcode, pdu_id, connection->volume_percentage);
1017                     avrcp_target_emit_volume_changed(avrcp_target_context.avrcp_callback, connection->avrcp_cid, connection->volume_percentage);
1018                     break;
1019                 }
1020                 default:
1021                     log_info("AVRCP target: unhandled pdu id 0x%02x", pdu_id);
1022                     avrcp_target_response_reject(connection, subunit_type, subunit_id, opcode, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
1023                     break;
1024             }
1025             break;
1026         default:
1027             log_info("AVRCP target: opcode 0x%02x not implemented", avrcp_cmd_opcode(packet,size));
1028             break;
1029     }
1030 }
1031 
1032 static int avrcp_target_send_notification(uint16_t cid, avrcp_connection_t * connection, avrcp_notification_event_id_t notification_id, uint8_t * value, uint16_t value_len){
1033     if (!connection){
1034         log_error("avrcp tartget: could not find a connection.");
1035         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1036     }
1037 
1038     btstack_assert((value_len == 0) || (value != NULL));
1039 
1040     connection->command_opcode  = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
1041     connection->command_type    = AVRCP_CTYPE_RESPONSE_CHANGED_STABLE;
1042     connection->subunit_type    = AVRCP_SUBUNIT_TYPE_PANEL;
1043     connection->subunit_id      = AVRCP_SUBUNIT_ID;
1044     connection->transaction_id = avrcp_target_get_transaction_label_for_notification(connection, notification_id);
1045 
1046     uint16_t pos = 0;
1047     l2cap_reserve_packet_buffer();
1048     uint8_t * packet = l2cap_get_outgoing_buffer();
1049 
1050     // value <= 8 ==> pdu <= 22 < L2CAP Default MTU
1051     btstack_assert((14 + value_len) <= l2cap_get_remote_mtu_for_local_cid(connection->l2cap_signaling_cid));
1052 
1053     connection->packet_type = AVRCP_SINGLE_PACKET;
1054     packet[pos++] = (connection->transaction_id << 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 
1073     big_endian_store_16(packet, pos, 1 + value_len);
1074     pos += 2;
1075     packet[pos++] = notification_id;
1076     if (value_len > 0){
1077         (void)memcpy(packet + pos, value, value_len);
1078         pos += value_len;
1079     }
1080 
1081     return l2cap_send_prepared(cid, pos);
1082 }
1083 
1084 static void avrcp_target_reset_notification(avrcp_connection_t * connection, avrcp_notification_event_id_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     avrcp_target_set_transaction_label_for_notification(connection, notification_id, 0);
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 = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, channel);
1099             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1100             break;
1101         case HCI_EVENT_PACKET:
1102             switch (hci_event_packet_get_type(packet)){
1103                 case L2CAP_EVENT_CAN_SEND_NOW:{
1104                     connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, channel);
1105 
1106                     if (connection->accept_response){
1107                         connection->accept_response = 0;
1108                         avrcp_target_send_response(connection->l2cap_signaling_cid, connection);
1109                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1110                         return;
1111                     }
1112 
1113                     if (connection->abort_continue_response){
1114                         connection->abort_continue_response = 0;
1115                         connection->now_playing_info_response = 0;
1116                         avrcp_target_abort_continue_response(connection->l2cap_signaling_cid, connection);
1117                         return;
1118                     }
1119 
1120                     if (connection->now_playing_info_response){
1121                         connection->now_playing_info_response = 0;
1122                         avrcp_target_send_now_playing_info(connection->l2cap_signaling_cid, connection);
1123                         return;
1124                     }
1125 
1126                     if (connection->track_changed){
1127                         connection->track_changed = 0;
1128                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED, connection->track_id, 8);
1129                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED);
1130                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1131                         return;
1132                     }
1133 
1134                     if (connection->playback_status_changed){
1135                         connection->playback_status_changed = 0;
1136                         uint8_t playback_status = (uint8_t) connection->playback_status;
1137                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED, &playback_status, 1);
1138                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED);
1139                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1140                         return;
1141                     }
1142 
1143                     if (connection->playing_content_changed){
1144                         connection->playing_content_changed = 0;
1145                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED, NULL, 0);
1146                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED);
1147                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1148                         return;
1149                     }
1150 
1151                     if (connection->battery_status_changed){
1152                         connection->battery_status_changed = 0;
1153                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED, (uint8_t *)&connection->battery_status, 1);
1154                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED);
1155                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1156                         return;
1157                     }
1158 
1159                     if (connection->notify_volume_percentage_changed){
1160                         connection->notify_volume_percentage_changed = 0;
1161                         avrcp_target_send_notification(connection->l2cap_signaling_cid, connection, AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED, &connection->volume_percentage, 1);
1162                         avrcp_target_reset_notification(connection, AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED);
1163                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1164                         return;
1165                     }
1166 
1167                     if (connection->reject_transport_header){
1168                         connection->state = AVCTP_CONNECTION_OPENED;
1169                         connection->reject_transport_header = 0;
1170                         l2cap_reserve_packet_buffer();
1171                         uint8_t * out_buffer = l2cap_get_outgoing_buffer();
1172                         out_buffer[0] = connection->transport_header;
1173                         big_endian_store_16(out_buffer, 1, connection->invalid_pid);
1174                         l2cap_send_prepared(connection->l2cap_signaling_cid, 3);
1175                         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1176                         return;
1177                     }
1178 
1179                     switch (connection->state){
1180                         case AVCTP_W2_SEND_RESPONSE:
1181                             connection->state = AVCTP_CONNECTION_OPENED;
1182                             avrcp_target_send_response(connection->l2cap_signaling_cid, connection);
1183                             avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1184                             return;
1185                         default:
1186                             break;
1187                     }
1188 
1189                     break;
1190             }
1191             default:
1192                 break;
1193         }
1194         default:
1195             break;
1196     }
1197 }
1198 
1199 void avrcp_target_init(void){
1200     avrcp_target_context.role = AVRCP_TARGET;
1201     avrcp_target_context.packet_handler = avrcp_target_packet_handler;
1202     avrcp_register_target_packet_handler(&avrcp_target_packet_handler);
1203 }
1204 
1205 void avrcp_target_deinit(void){
1206     memset(&avrcp_target_context, 0, sizeof(avrcp_context_t));
1207 }
1208 
1209 void avrcp_target_register_packet_handler(btstack_packet_handler_t callback){
1210     btstack_assert(callback != NULL);
1211     avrcp_target_context.avrcp_callback = callback;
1212 }
1213 
1214 void avrcp_target_register_set_addressed_player_handler(bool (*callback)(uint16_t player_id)){
1215     btstack_assert(callback != NULL);
1216     avrcp_target_context.set_addressed_player_callback = callback;
1217 }
1218 
1219 
1220