xref: /btstack/src/classic/avrcp_target.c (revision f3bb6622e45d1968c4fb9b4bf850bc7f3b9e5ad5)
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 BLUEKITCHEN
24  * GMBH 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 #include <stdio.h>
55 #define AVRCP_ATTR_HEADER_LEN  8
56 
57 static const uint8_t AVRCP_NOTIFICATION_TRACK_SELECTED[] = {0,0,0,0,0,0,0,0};
58 static const uint8_t AVRCP_NOTIFICATION_TRACK_NOT_SELECTED[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
59 
60 avrcp_context_t avrcp_target_context;
61 
62 static uint32_t default_companies[] = {
63     0x581900 //BT SIG registered CompanyID
64 };
65 
66 static int avrcp_target_supports_browsing(uint16_t target_supported_features){
67     return target_supported_features & AVRCP_FEATURE_MASK_BROWSING;
68 }
69 
70 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){
71     avrcp_create_sdp_record(0, service, service_record_handle, avrcp_target_supports_browsing(supported_features), supported_features, service_name, service_provider_name);
72 }
73 
74 static void
75 avrcp_target_emit_operation(btstack_packet_handler_t callback, uint16_t avrcp_cid, avrcp_operation_id_t operation_id,
76                             bool button_pressed, uint8_t operands_length, uint8_t operand) {
77     btstack_assert(callback != NULL);
78 
79     uint8_t event[9];
80     int pos = 0;
81     event[pos++] = HCI_EVENT_AVRCP_META;
82     event[pos++] = sizeof(event) - 2;
83     event[pos++] = AVRCP_SUBEVENT_OPERATION;
84     little_endian_store_16(event, pos, avrcp_cid);
85     pos += 2;
86     event[pos++] = operation_id;
87     event[pos++] = button_pressed ? 1 : 0;
88     event[pos++] = operands_length;
89     event[pos++] = operand;
90     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
91 }
92 
93 static void avrcp_target_emit_volume_changed(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t absolute_volume){
94     btstack_assert(callback != NULL);
95 
96     uint8_t event[7];
97     int offset = 0;
98     event[offset++] = HCI_EVENT_AVRCP_META;
99     event[offset++] = sizeof(event) - 2;
100     event[offset++] = AVRCP_SUBEVENT_NOTIFICATION_VOLUME_CHANGED;
101     little_endian_store_16(event, offset, avrcp_cid);
102     offset += 2;
103     event[offset++] = AVRCP_CTYPE_NOTIFY;
104     event[offset++] = absolute_volume;
105     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
106 }
107 
108 static void avrcp_target_emit_respond_vendor_dependent_query(btstack_packet_handler_t callback, uint16_t avrcp_cid, uint8_t subevent_id){
109     btstack_assert(callback != NULL);
110 
111     uint8_t event[5];
112     int pos = 0;
113     event[pos++] = HCI_EVENT_AVRCP_META;
114     event[pos++] = sizeof(event) - 2;
115     event[pos++] = subevent_id;
116     little_endian_store_16(event, pos, avrcp_cid);
117     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
118 }
119 
120 // returns number of bytes stored
121 static uint16_t avrcp_target_pack_single_element_header(uint8_t * buffer, avrcp_media_attribute_id_t attr_id, uint16_t attr_value_size){
122     btstack_assert(attr_id > AVRCP_MEDIA_ATTR_ALL);
123     btstack_assert(attr_id < AVRCP_MEDIA_ATTR_RESERVED);
124     uint16_t pos = 0;
125     big_endian_store_32(buffer, pos, attr_id);
126     big_endian_store_16(buffer, pos + 4, RFC2978_CHARSET_MIB_UTF8);
127     big_endian_store_16(buffer, pos + 6, attr_value_size);
128     return 8;
129 }
130 
131 static uint16_t avrcp_now_playing_info_attr_id_value_len(avrcp_connection_t * connection, avrcp_media_attribute_id_t attr_id){
132     char buffer[AVRCP_MAX_ATTRIBUTE_SIZE];
133     uint16_t str_len;
134     switch (attr_id) {
135         case AVRCP_MEDIA_ATTR_ALL:
136         case AVRCP_MEDIA_ATTR_NONE:
137             return 0;
138         case AVRCP_MEDIA_ATTR_TRACK:
139             str_len = sprintf(buffer, "%0" PRIu32, connection->target_track_nr);
140             break;
141         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
142             str_len = sprintf(buffer, "%0" PRIu32, connection->target_total_tracks);
143             break;
144         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
145             str_len = sprintf(buffer, "%0" PRIu32, connection->target_song_length_ms);
146             break;
147         default:
148             str_len = connection->target_now_playing_info[(uint16_t)attr_id - 1].len;
149             break;
150     }
151     return str_len;
152 }
153 
154 static uint16_t avrcp_now_playing_info_value_len_with_headers(avrcp_connection_t * connection){
155     uint16_t playing_info_len = 0;
156 
157     uint8_t i;
158     for ( i = (uint8_t)AVRCP_MEDIA_ATTR_ALL + 1; i < (uint8_t) AVRCP_MEDIA_ATTR_RESERVED; i++){
159         avrcp_media_attribute_id_t attr_id = (avrcp_media_attribute_id_t) i;
160 
161         if ((connection->target_now_playing_info_attr_bitmap & (1 << attr_id)) == 0) {
162             continue;
163         }
164 
165         switch (attr_id) {
166             case AVRCP_MEDIA_ATTR_ALL:
167             case AVRCP_MEDIA_ATTR_NONE:
168             case AVRCP_MEDIA_ATTR_DEFAULT_COVER_ART:
169                 break;
170             default:
171                 playing_info_len += AVRCP_ATTR_HEADER_LEN + avrcp_now_playing_info_attr_id_value_len(connection, attr_id);
172                 break;
173         }
174     }
175     // for total num bytes that of the attributes + headers
176     playing_info_len += 1;
177     return playing_info_len;
178 }
179 
180 static uint8_t * avrcp_get_attribute_value_from_u32(avrcp_connection_t * connection, uint32_t value, uint16_t * num_bytes_to_copy){
181     *num_bytes_to_copy = 0;
182 
183     if (connection->attribute_value_len == 0){
184         connection->attribute_value_len = sprintf((char *)connection->attribute_value, "%0" PRIu32, value);
185         connection->attribute_value_offset = 0;
186     }
187     *num_bytes_to_copy = connection->attribute_value_len - connection->attribute_value_offset;
188     return connection->attribute_value + connection->attribute_value_offset;
189 }
190 
191 static uint8_t * avrcp_get_next_value_fragment_for_attribute_id(avrcp_connection_t * connection, avrcp_media_attribute_id_t attr_id, uint16_t * num_bytes_to_copy){
192     switch (attr_id){
193         case AVRCP_MEDIA_ATTR_TRACK:
194             return avrcp_get_attribute_value_from_u32(connection, connection->target_track_nr, num_bytes_to_copy);
195         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
196             return avrcp_get_attribute_value_from_u32(connection, connection->target_total_tracks, num_bytes_to_copy);
197         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
198             return avrcp_get_attribute_value_from_u32(connection, connection->target_song_length_ms, num_bytes_to_copy);
199         default:
200             break;
201     }
202     int attr_index = attr_id - 1;
203     if (connection->attribute_value_len == 0){
204         connection->attribute_value_len = avrcp_now_playing_info_attr_id_value_len(connection, attr_id);
205         connection->attribute_value_offset = 0;
206     }
207     *num_bytes_to_copy = connection->target_now_playing_info[attr_index].len - connection->attribute_value_offset;
208     return (uint8_t *) (connection->target_now_playing_info[attr_index].value + connection->attribute_value_offset);
209 }
210 
211 // TODO Review
212 static uint16_t avrcp_store_avctp_now_playing_info_fragment(avrcp_connection_t * connection, uint16_t packet_size, uint8_t * packet){
213     uint16_t num_free_bytes = packet_size;
214 
215     uint16_t bytes_stored = 0;
216 
217     while ((num_free_bytes > 0) && (connection->next_attr_id <= AVRCP_MEDIA_ATTR_SONG_LENGTH_MS)){
218         if ((connection->target_now_playing_info_attr_bitmap & (1 << (uint8_t)connection->next_attr_id)) == 0) {
219             connection->next_attr_id = (avrcp_media_attribute_id_t) (((int) connection->next_attr_id) + 1);
220             continue;
221         }
222 
223         // prepare attribute value
224         uint16_t num_bytes_to_copy;
225         uint8_t * attr_value_with_offset = avrcp_get_next_value_fragment_for_attribute_id(connection,
226                                                                                           connection->next_attr_id,
227                                                                                           &num_bytes_to_copy);
228 
229         // store header
230         if (connection->attribute_value_offset == 0){
231             // pack the whole attribute value header
232             if (connection->parser_attribute_header_pos == 0) {
233                 avrcp_target_pack_single_element_header(connection->parser_attribute_header, connection->next_attr_id,
234                                                         connection->attribute_value_len);
235             }
236         }
237 
238         if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN){
239             uint16_t num_header_bytes_to_store = btstack_min(num_free_bytes, AVRCP_ATTRIBUTE_HEADER_LEN - connection->parser_attribute_header_pos);
240             memcpy(packet + bytes_stored, connection->parser_attribute_header + connection->parser_attribute_header_pos, num_header_bytes_to_store);
241             connection->parser_attribute_header_pos += num_header_bytes_to_store;
242             bytes_stored += num_header_bytes_to_store;
243             num_free_bytes -= num_header_bytes_to_store;
244             connection->data_offset += num_header_bytes_to_store;
245 
246             if (num_free_bytes == 0){
247                 continue;
248             }
249         }
250 
251         // store value
252         uint16_t num_attr_value_bytes_to_store = btstack_min(num_free_bytes, connection->attribute_value_len - connection->attribute_value_offset);
253         memcpy(packet + bytes_stored, attr_value_with_offset, num_attr_value_bytes_to_store);
254         bytes_stored   += num_attr_value_bytes_to_store;
255         num_free_bytes -= num_attr_value_bytes_to_store;
256         connection->attribute_value_offset += num_attr_value_bytes_to_store;
257         connection->data_offset += num_attr_value_bytes_to_store;
258 
259         if (connection->attribute_value_offset == connection->attribute_value_len){
260             // C++ compatible version of connection->next_attr_id++
261             connection->next_attr_id = (avrcp_media_attribute_id_t) (((int) connection->next_attr_id) + 1);
262             connection->attribute_value_offset = 0;
263             connection->attribute_value_len = 0;
264             connection->parser_attribute_header_pos = 0;
265         }
266     }
267     return bytes_stored;
268 }
269 
270 static void avrcp_send_response_with_avctp_fragmentation(avrcp_connection_t * connection){
271     l2cap_reserve_packet_buffer();
272     uint8_t * packet = l2cap_get_outgoing_buffer();
273 
274     // transport header
275     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
276 
277     uint16_t max_payload_size;
278     connection->avctp_packet_type = avctp_get_packet_type(connection, &max_payload_size);
279     connection->avrcp_packet_type = avrcp_get_packet_type(connection);
280 
281     // AVCTP header
282     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
283     uint16_t pos = 0;
284     packet[pos++] = (connection->transaction_id << 4) | (connection->avctp_packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
285 
286     uint8_t param_len = connection->data_len;
287 
288     if (connection->avctp_packet_type == AVCTP_START_PACKET){
289         uint8_t max_frame_size = btstack_min(l2cap_get_remote_mtu_for_local_cid(connection->l2cap_signaling_cid), AVRCP_MAX_AV_C_MESSAGE_FRAME_SIZE);
290         // first packet: max_payload_size
291         // rest packets
292         uint16_t num_payload_bytes = param_len - max_payload_size;
293         uint16_t frame_size_for_continue_packet = max_frame_size - avctp_get_num_bytes_for_header(AVCTP_CONTINUE_PACKET);
294         uint16_t num_avctp_packets = (num_payload_bytes + frame_size_for_continue_packet - 1)/frame_size_for_continue_packet + 1;
295         packet[pos++] = num_avctp_packets;
296     }
297 
298     uint16_t bytes_stored = 0;
299     uint8_t i;
300 
301     switch (connection->avctp_packet_type) {
302         case AVCTP_SINGLE_PACKET:
303         case AVCTP_START_PACKET:
304             // Profile IDentifier (PID)
305             packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
306             packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
307 
308             // AVRCP message
309             // command_type
310             packet[pos++] = connection->command_type;
311             // subunit_type | subunit ID
312             packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
313             // opcode
314             packet[pos++] = (uint8_t) connection->command_opcode;
315 
316             switch (connection->command_opcode) {
317                 case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
318                     big_endian_store_24(packet, pos, connection->company_id);
319                     pos += 3;
320                     packet[pos++] = connection->pdu_id;
321                     // AVRCP packet type
322 
323                     packet[pos++] = (uint8_t)connection->avrcp_packet_type;
324                     // parameter length
325                     big_endian_store_16(packet, pos, param_len);
326                     pos += 2;
327 
328                     switch (connection->pdu_id) {
329                         // message is small enough to fit the single packet, no need for extra check
330                         case AVRCP_PDU_ID_GET_CAPABILITIES:
331                             // capability ID
332                             packet[pos++] = connection->data[0];
333                             // num_capabilities
334                             packet[pos++] = connection->data[1];
335 
336                             switch ((avrcp_capability_id_t) connection->data[0]) {
337                                 case AVRCP_CAPABILITY_ID_EVENT:
338                                     for (i = (uint8_t) AVRCP_NOTIFICATION_EVENT_FIRST_INDEX;
339                                          i < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; i++) {
340                                         if ((connection->notifications_supported_by_target & (1 << i)) == 0) {
341                                             continue;
342                                         }
343                                         packet[pos++] = i;
344                                     }
345                                     break;
346                                 case AVRCP_CAPABILITY_ID_COMPANY:
347                                     // use Bluetooth SIG as default company
348                                     for (i = 0; i < connection->data[1]; i++) {
349                                         little_endian_store_24(packet, pos,
350                                                                connection->target_supported_companies[i]);
351                                         pos += 3;
352                                     }
353                                     break;
354                                 default:
355                                     // error response
356                                     break;
357                             }
358                             l2cap_send_prepared(connection->l2cap_signaling_cid, pos);
359                             return;
360 
361                         case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:
362                             packet[pos++] = count_set_bits_uint32(connection->target_now_playing_info_attr_bitmap);
363                             max_payload_size--;
364 
365                             bytes_stored = avrcp_store_avctp_now_playing_info_fragment(connection, max_payload_size, packet + pos);
366 
367                             connection->avrcp_frame_bytes_sent += bytes_stored + pos;
368                             l2cap_send_prepared(connection->l2cap_signaling_cid, pos + bytes_stored);
369                             return;
370 
371                         default:
372                             // error response and other OPCODEs
373                             break;
374                     }
375                     break;
376 
377                 case AVRCP_CMD_OPCODE_PASS_THROUGH:
378                     packet[pos++] = connection->operation_id;
379                     // parameter length
380                     packet[pos++] = (uint8_t) connection->data_len;
381                     pos += 2;
382                     break;
383                 case AVRCP_CMD_OPCODE_UNIT_INFO:
384                     break;
385                 case AVRCP_CMD_OPCODE_SUBUNIT_INFO:
386                     break;
387                 default:
388                     btstack_assert(false);
389                     return;
390             }
391             break;
392         case AVCTP_CONTINUE_PACKET:
393         case AVCTP_END_PACKET:
394             switch (connection->pdu_id) {
395                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:
396                     bytes_stored = avrcp_store_avctp_now_playing_info_fragment(connection, max_payload_size, packet + pos);
397 
398                     connection->avrcp_frame_bytes_sent += bytes_stored + pos;
399                     l2cap_send_prepared(connection->l2cap_signaling_cid, pos + bytes_stored);
400                     return;
401 
402                 default:
403                     break;
404             }
405             break;
406         default:
407             btstack_assert(false);
408             return;
409     }
410 
411     // compare number of bytes to store with the remaining buffer size
412     uint16_t bytes_to_copy = btstack_min(connection->data_len - connection->data_offset, max_payload_size - pos);
413 
414     (void)memcpy(packet + pos, &connection->data[connection->data_offset], bytes_to_copy);
415     pos += bytes_to_copy;
416     connection->data_offset += bytes_to_copy;
417     connection->avrcp_frame_bytes_sent += pos;
418 
419     l2cap_send_prepared(connection->l2cap_signaling_cid, pos);
420 }
421 
422 static void avctp_send_reject_cmd_wrong_pid(avrcp_connection_t * connection){
423     l2cap_reserve_packet_buffer();
424     uint8_t * packet = l2cap_get_outgoing_buffer();
425 
426     // AVCTP header
427     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
428     packet[0] = (connection->transaction_id << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_RESPONSE_FRAME << 1) | 1;
429     big_endian_store_16(packet, 1, connection->message_body[0]);
430     l2cap_send_prepared(connection->l2cap_signaling_cid, 3);
431 }
432 
433 static void avrcp_target_custome_command_data_init(avrcp_connection_t * connection,
434     avrcp_command_opcode_t opcode, avrcp_command_type_t command_type,
435     avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id,
436     avrcp_pdu_id_t pdu_id, uint32_t company_id){
437 
438     connection->command_opcode = opcode;
439     connection->command_type = command_type;
440     connection->subunit_type = subunit_type;
441     connection->subunit_id = subunit_id;
442     connection->company_id = company_id << 16;
443     connection->pdu_id = pdu_id;
444     connection->data = NULL;
445     connection->data_offset = 0;
446     connection->data_len = 0;
447 }
448 
449 static void avrcp_target_vendor_dependent_response_data_init(avrcp_connection_t * connection, avrcp_command_type_t command_type, avrcp_pdu_id_t pdu_id){
450     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
451     connection->subunit_type   = AVRCP_SUBUNIT_TYPE_PANEL;
452     connection->subunit_id     = AVRCP_SUBUNIT_ID;
453     connection->company_id     = BT_SIG_COMPANY_ID;
454 
455     connection->command_type = command_type;
456     connection->pdu_id = pdu_id;
457     connection->data = connection->message_body;
458     connection->data_offset = 0;
459     connection->avrcp_frame_bytes_sent = 0;
460     connection->state = AVCTP_W2_SEND_RESPONSE;
461 }
462 
463 static void avrcp_target_pass_through_command_data_init(avrcp_connection_t * connection, avrcp_command_type_t command_type, avrcp_operation_id_t opid){
464     connection->command_opcode = AVRCP_CMD_OPCODE_PASS_THROUGH;
465     connection->subunit_type   = AVRCP_SUBUNIT_TYPE_PANEL;
466     connection->subunit_id     = AVRCP_SUBUNIT_ID;
467 
468     connection->command_type = command_type;
469     connection->company_id = 0;
470     connection->pdu_id = AVRCP_PDU_ID_UNDEFINED;
471     connection->operation_id = opid;
472 
473     connection->data = connection->message_body;
474     connection->data_offset = 0;
475     connection->data_len = 0;
476 }
477 
478 
479 static uint8_t avrcp_target_vendor_dependent_response_accept(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, uint8_t status){
480     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_ACCEPTED, pdu_id);
481     connection->data_len = 1;
482     connection->data[0] = status;
483 
484     connection->target_accept_response = true;
485     connection->state = AVCTP_W2_SEND_RESPONSE;
486     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
487     return ERROR_CODE_SUCCESS;
488 }
489 
490 static uint8_t avrcp_target_response_vendor_dependent_reject(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, avrcp_status_code_t status){
491     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_REJECTED, pdu_id);
492     connection->data_len = 1;
493     connection->data[0] = status;
494 
495     connection->state = AVCTP_W2_SEND_RESPONSE;
496     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
497     return ERROR_CODE_SUCCESS;
498 }
499 
500 static uint8_t avrcp_target_response_vendor_dependent_not_implemented(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, uint8_t event_id){
501     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_NOT_IMPLEMENTED, pdu_id);
502     connection->data_len = 1;
503     connection->data[0] = event_id;
504 
505     connection->state = AVCTP_W2_SEND_RESPONSE;
506     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
507     return ERROR_CODE_SUCCESS;
508 }
509 
510 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){
511     btstack_assert(value_len + 1 < AVRCP_MAX_COMMAND_PARAMETER_LENGTH);
512 
513     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_INTERIM, pdu_id);
514     connection->data_len = 1 + value_len;
515     connection->data[0] = event_id;
516 
517     if (value && (value_len > 0)){
518         (void)memcpy(connection->data + 1, value, value_len);
519     }
520 
521     connection->state = AVCTP_W2_SEND_RESPONSE;
522     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
523     return ERROR_CODE_SUCCESS;
524 }
525 
526 static uint8_t avrcp_target_response_addressed_player_changed_interim(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, uint8_t event_id){
527     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_INTERIM, pdu_id);
528 
529     connection->data_len = 5;
530     connection->data[0] = event_id;
531     big_endian_store_16(connection->data, 1, connection->target_addressed_player_id);
532     big_endian_store_16(connection->data, 3, connection->target_uid_counter);
533 
534     connection->state = AVCTP_W2_SEND_RESPONSE;
535     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
536     return ERROR_CODE_SUCCESS;
537 }
538 
539 static uint8_t avrcp_target_pass_through_response(uint16_t avrcp_cid, avrcp_command_type_t ctype, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
540     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
541     if (!connection){
542         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
543     }
544     avrcp_target_pass_through_command_data_init(connection, ctype, opid);
545 
546     if (operands_length == 1){
547         connection->data_len = 1;
548         connection->message_body[0] = operand;
549     }
550 
551     connection->state = AVCTP_W2_SEND_RESPONSE;
552     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
553     return ERROR_CODE_SUCCESS;
554 }
555 
556 uint8_t avrcp_target_operation_rejected(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
557     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_REJECTED, opid, operands_length, operand);
558 }
559 
560 uint8_t avrcp_target_operation_accepted(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
561     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_ACCEPTED, opid, operands_length, operand);
562 }
563 
564 uint8_t avrcp_target_operation_not_implemented(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
565     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_ACCEPTED, opid, operands_length, operand);
566 }
567 
568 uint8_t avrcp_target_set_unit_info(uint16_t avrcp_cid, avrcp_subunit_type_t unit_type, uint32_t company_id){
569     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
570     if (!connection){
571         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
572     }
573     connection->target_unit_type = unit_type;
574     connection->company_id = company_id;
575     return ERROR_CODE_SUCCESS;
576 }
577 
578 uint8_t 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){
579     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
580     if (!connection){
581         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
582     }
583     connection->target_subunit_info_type = subunit_type;
584     connection->target_subunit_info_data = subunit_info_data;
585     connection->target_subunit_info_data_size = subunit_info_data_size;
586     return ERROR_CODE_SUCCESS;
587 }
588 
589 // TODO Review
590 static uint8_t avrcp_target_unit_info(avrcp_connection_t * connection){
591     if (connection->state != AVCTP_CONNECTION_OPENED){
592         return ERROR_CODE_COMMAND_DISALLOWED;
593     }
594     connection->state = AVCTP_W2_SEND_RESPONSE;
595 
596     avrcp_target_custom_command_data_init(connection,
597                                           AVRCP_CMD_OPCODE_UNIT_INFO, AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE,
598                                           AVRCP_SUBUNIT_TYPE_UNIT, AVRCP_SUBUNIT_ID_IGNORE, AVRCP_PDU_ID_UNDEFINED,
599                                           connection->company_id);
600 
601     uint8_t unit = 0;
602     connection->data = connection->message_body;
603     connection->data_len = 5;
604     connection->data[0] = 0x07;
605     connection->data[1] = (connection->target_unit_type << 4) | unit;
606     // company id is 3 bytes long
607     big_endian_store_24(connection->data, 2, connection->company_id);
608 
609     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
610     return ERROR_CODE_SUCCESS;
611 }
612 
613 // TODO Review
614 static uint8_t avrcp_target_subunit_info(avrcp_connection_t * connection, uint8_t offset){
615     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
616     if (offset >= 32) return AVRCP_STATUS_INVALID_PARAMETER;
617 
618     connection->state = AVCTP_W2_SEND_RESPONSE;
619 
620     avrcp_target_custom_command_data_init(connection, AVRCP_CMD_OPCODE_SUBUNIT_INFO,
621                                           AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE,
622                                           AVRCP_SUBUNIT_TYPE_UNIT, AVRCP_SUBUNIT_ID_IGNORE, AVRCP_PDU_ID_UNDEFINED,
623                                           connection->company_id);
624 
625     uint8_t page = offset / 4;
626     uint8_t extension_code = 7;
627     connection->data = connection->message_body;
628     connection->data_len = 5;
629     connection->data[0] = (page << 4) | extension_code;
630 
631     // mark non-existent entries with 0xff
632     memset(&connection->message_body[1], 0xFF, 4);
633     if ((connection->data != NULL) && (offset < connection->target_subunit_info_data_size)){
634         uint8_t bytes_to_copy = btstack_min(connection->target_subunit_info_data_size - offset, 4);
635         memcpy(&connection->data[1], &connection->target_subunit_info_data[offset], bytes_to_copy);
636     }
637 
638     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
639     return ERROR_CODE_SUCCESS;
640 }
641 
642 static uint8_t avrcp_target_response_vendor_dependent_supported_events(avrcp_connection_t * connection){
643     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE, AVRCP_PDU_ID_GET_CAPABILITIES);
644     connection->state = AVCTP_W2_SEND_RESPONSE;
645 
646     uint8_t event_id;
647     uint8_t num_events = 0;
648     for (event_id = (uint8_t) AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
649         if ((connection->notifications_supported_by_target & (1 << event_id)) == 0){
650             continue;
651         }
652         num_events++;
653     }
654 
655     connection->data[0] = AVRCP_CAPABILITY_ID_EVENT;
656     connection->data[1] = num_events;
657     connection->data_len = 2 + num_events;
658 
659     // fill the data later directly to the L2CAP outgoing buffer
660     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
661     return ERROR_CODE_SUCCESS;
662 }
663 
664 static uint8_t avrcp_target_response_vendor_dependent_supported_companies(avrcp_connection_t * connection){
665     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE, AVRCP_PDU_ID_GET_CAPABILITIES);
666     connection->state = AVCTP_W2_SEND_RESPONSE;
667 
668     connection->data[0] = AVRCP_CAPABILITY_ID_COMPANY;
669     if (connection->target_supported_companies_num == 0){
670         connection->target_supported_companies_num = 1;
671         connection->target_supported_companies = default_companies;
672     }
673 
674     connection->data[1] = connection->target_supported_companies_num;
675     connection->data_len = 2 + connection->data[1] * 3;
676 
677     // fill the data later directly to the L2CAP outgoing buffer and
678     // use Bluetooth SIG as default company
679     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
680     return ERROR_CODE_SUCCESS;
681 }
682 
683 uint8_t avrcp_target_support_event(uint16_t avrcp_cid, avrcp_notification_event_id_t event_id){
684     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
685     if (!connection){
686         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
687     }
688 
689     if ((event_id < (uint8_t)AVRCP_NOTIFICATION_EVENT_FIRST_INDEX) || (event_id > (uint8_t)AVRCP_NOTIFICATION_EVENT_LAST_INDEX)){
690         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
691     }
692 
693     connection->notifications_supported_by_target |= (1 << (uint8_t)event_id);
694     return ERROR_CODE_SUCCESS;
695 }
696 
697 uint8_t avrcp_target_support_companies(uint16_t avrcp_cid, uint8_t num_companies, const uint32_t *companies){
698     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
699     if (!connection){
700         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
701     }
702 
703     connection->target_supported_companies_num = num_companies;
704     connection->target_supported_companies     = companies;
705     return ERROR_CODE_SUCCESS;
706 }
707 
708 // TODO Review (use flags)
709 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){
710     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
711     if (!connection){
712         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
713     }
714     if (connection->state != AVCTP_CONNECTION_OPENED){
715         return ERROR_CODE_COMMAND_DISALLOWED;
716     }
717 
718     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE, AVRCP_PDU_ID_GET_PLAY_STATUS);
719     connection->data_len = 9;
720     big_endian_store_32(connection->data, 0, song_length_ms);
721     big_endian_store_32(connection->data, 4, song_position_ms);
722     connection->data[8] = play_status;
723 
724     connection->state = AVCTP_W2_SEND_RESPONSE;
725     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
726     return ERROR_CODE_SUCCESS;
727 }
728 
729 static uint8_t avrcp_target_store_media_attr(avrcp_connection_t * connection, avrcp_media_attribute_id_t attr_id, const char * value){
730     int index = attr_id - 1;
731     if (!value) return AVRCP_STATUS_INVALID_PARAMETER;
732     connection->target_now_playing_info[index].value = (uint8_t*)value;
733     connection->target_now_playing_info[index].len   = strlen(value);
734     return ERROR_CODE_SUCCESS;
735 }
736 
737 uint8_t avrcp_target_set_playback_status(uint16_t avrcp_cid, avrcp_playback_status_t playback_status){
738     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
739     if (!connection){
740         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
741     }
742     if (connection->target_playback_status == playback_status){
743         return ERROR_CODE_SUCCESS;
744     }
745 
746     connection->target_playback_status = playback_status;
747     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED)) {
748         connection->target_playback_status_changed = true;
749         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
750     }
751     return ERROR_CODE_SUCCESS;
752 }
753 
754 uint8_t avrcp_target_set_now_playing_info(uint16_t avrcp_cid, const avrcp_track_t * current_track, uint16_t total_tracks){
755     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
756     if (!connection){
757         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
758     }
759     if (!current_track){
760         connection->target_track_selected = false;
761         connection->target_playback_status = AVRCP_PLAYBACK_STATUS_ERROR;
762         return ERROR_CODE_COMMAND_DISALLOWED;
763     }
764 
765     (void)memcpy(connection->target_track_id, current_track->track_id, 8);
766     connection->target_song_length_ms = current_track->song_length_ms;
767     connection->target_track_nr = current_track->track_nr;
768     connection->target_total_tracks = total_tracks;
769     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_TITLE, current_track->title);
770     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ARTIST, current_track->artist);
771     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ALBUM, current_track->album);
772     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_GENRE, current_track->genre);
773 
774     connection->target_track_selected = true;
775 
776     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED)) {
777         connection->target_track_changed = true;
778         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
779     }
780     return ERROR_CODE_SUCCESS;
781 }
782 
783 uint8_t avrcp_target_track_changed(uint16_t avrcp_cid, uint8_t * track_id){
784     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
785     if (!connection){
786         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
787     }
788     if (!track_id){
789         return ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
790     }
791 
792     (void)memcpy(connection->target_track_id, track_id, 8);
793     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED)) {
794         connection->target_track_changed = true;
795         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
796     }
797     return ERROR_CODE_SUCCESS;
798 }
799 
800 uint8_t avrcp_target_playing_content_changed(uint16_t avrcp_cid){
801     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
802     if (!connection){
803         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
804     }
805     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED)) {
806         connection->target_playing_content_changed = true;
807         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
808     }
809     return ERROR_CODE_SUCCESS;
810 }
811 
812 uint8_t avrcp_target_addressed_player_changed(uint16_t avrcp_cid, uint16_t player_id, uint16_t uid_counter){
813     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
814     if (!connection){
815         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
816     }
817 
818     if (connection->target_addressed_player_id == player_id){
819         return ERROR_CODE_SUCCESS;
820     }
821 
822     connection->target_uid_counter = uid_counter;
823     connection->target_addressed_player_id = player_id;
824 
825     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED)) {
826         connection->target_addressed_player_changed = true;
827         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
828     }
829     return ERROR_CODE_SUCCESS;
830 }
831 
832 uint8_t avrcp_target_battery_status_changed(uint16_t avrcp_cid, avrcp_battery_status_t battery_status){
833     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
834     if (!connection){
835         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
836     }
837     if (connection->target_battery_status == battery_status){
838         return ERROR_CODE_SUCCESS;
839     }
840 
841     connection->target_battery_status = battery_status;
842 
843     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED)) {
844         connection->target_battery_status_changed = true;
845         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
846     }
847     return ERROR_CODE_SUCCESS;
848 }
849 
850 uint8_t avrcp_target_adjust_absolute_volume(uint16_t avrcp_cid, uint8_t absolute_volume){
851     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
852     if (!connection){
853         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
854     }
855 
856     connection->target_absolute_volume = absolute_volume;
857     return ERROR_CODE_SUCCESS;
858 }
859 
860 uint8_t avrcp_target_volume_changed(uint16_t avrcp_cid, uint8_t absolute_volume){
861     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
862     if (!connection){
863         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
864     }
865     if (connection->target_absolute_volume == absolute_volume){
866         return ERROR_CODE_SUCCESS;
867     }
868 
869     connection->target_absolute_volume = absolute_volume;
870 
871     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED )) {
872         connection->target_notify_absolute_volume_changed = true;
873         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
874     }
875     return ERROR_CODE_SUCCESS;
876 }
877 
878 static void avrcp_target_set_transaction_label_for_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t notification, uint8_t transaction_label){
879     if (notification > AVRCP_NOTIFICATION_EVENT_MAX_VALUE) return;
880     connection->target_notifications_transaction_label[notification] = transaction_label;
881 }
882 
883 static uint8_t avrcp_target_get_transaction_label_for_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t notification){
884     if (notification > AVRCP_NOTIFICATION_EVENT_MAX_VALUE) return 0;
885     return connection->target_notifications_transaction_label[notification];
886 }
887 
888 static bool avcrp_operation_id_is_valid(avrcp_operation_id_t operation_id){
889     if (operation_id < AVRCP_OPERATION_ID_RESERVED_1) return true;
890 
891     if (operation_id < AVRCP_OPERATION_ID_0) return false;
892     if (operation_id < AVRCP_OPERATION_ID_RESERVED_2) return true;
893 
894     if (operation_id < AVRCP_OPERATION_ID_CHANNEL_UP) return false;
895     if (operation_id < AVRCP_OPERATION_ID_RESERVED_3) return true;
896 
897     if (operation_id < AVRCP_OPERATION_ID_CHANNEL_UP) return false;
898     if (operation_id < AVRCP_OPERATION_ID_RESERVED_3) return true;
899 
900     if (operation_id < AVRCP_OPERATION_ID_SKIP) return false;
901     if (operation_id == AVRCP_OPERATION_ID_SKIP) return true;
902 
903     if (operation_id < AVRCP_OPERATION_ID_POWER) return false;
904     if (operation_id < AVRCP_OPERATION_ID_RESERVED_4) return true;
905 
906     if (operation_id < AVRCP_OPERATION_ID_ANGLE) return false;
907     if (operation_id < AVRCP_OPERATION_ID_RESERVED_5) return true;
908 
909     if (operation_id < AVRCP_OPERATION_ID_F1) return false;
910     if (operation_id < AVRCP_OPERATION_ID_RESERVED_6) return true;
911 
912     return false;
913 }
914 
915 
916 #ifdef ENABLE_AVCTP_FRAGMENTATION
917 static void avctp_reassemble_message(avrcp_connection_t * connection, avctp_packet_type_t packet_type, uint8_t *packet, uint16_t size){
918     // after header (transaction label and packet type)
919     uint16_t pos;
920     uint16_t bytes_to_store;
921 
922     switch (packet_type){
923         case AVCTP_START_PACKET:
924             if (size < 2) return;
925 
926             // store header
927             pos = 0;
928             connection->avctp_reassembly_buffer[pos] = packet[pos];
929             pos++;
930             connection->avctp_reassembly_size = pos;
931 
932             // NOTE: num packets not needed for reassembly, ignoring it does not pose security risk -> no need to store it
933             pos++;
934 
935             // PID in reassembled packet is at offset 1, it will be read later after the avctp_reassemble_message with AVCTP_END_PACKET is called
936 
937             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
938             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
939             connection->avctp_reassembly_size += bytes_to_store;
940             break;
941 
942         case AVCTP_CONTINUE_PACKET:
943         case AVCTP_END_PACKET:
944             if (size < 1) return;
945 
946             // store remaining data, ignore header
947             pos = 1;
948             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
949             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
950             connection->avctp_reassembly_size += bytes_to_store;
951             break;
952 
953         default:
954             return;
955     }
956 }
957 #endif
958 
959 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t * packet, uint16_t size){
960     uint8_t avctp_header = packet[0];
961     connection->transaction_id = avctp_header >> 4;
962 
963     avctp_packet_type_t avctp_packet_type = (avctp_packet_type_t) ((avctp_header & 0x0F) >> 2);
964     switch (avctp_packet_type){
965         case AVCTP_SINGLE_PACKET:
966             break;
967 
968 #ifdef ENABLE_AVCTP_FRAGMENTATION
969         case AVCTP_START_PACKET:
970         case AVCTP_CONTINUE_PACKET:
971             avctp_reassemble_message(connection, avctp_packet_type, packet, size);
972             return;
973 
974         case AVCTP_END_PACKET:
975             avctp_reassemble_message(connection, avctp_packet_type, packet, size);
976 
977             packet = connection->avctp_reassembly_buffer;
978             size   = connection->avctp_reassembly_size;
979             break;
980 #endif
981         default:
982             return;
983     }
984 
985     if (size < 6u) return;
986 
987     uint16_t pid = big_endian_read_16(packet, 1);
988 
989     if (pid != BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL){
990         log_info("Invalid pid 0x%02x, expected 0x%02x", pid, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
991         connection->target_reject_transport_header = true;
992         connection->target_invalid_pid = pid;
993         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
994         return;
995     }
996 
997     // avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (packet[4] >> 3);
998     // avrcp_subunit_id_t   subunit_id   = (avrcp_subunit_id_t) (packet[4] & 0x07);
999 
1000     avrcp_command_opcode_t opcode = (avrcp_command_opcode_t) avrcp_cmd_opcode(packet,size);
1001 
1002     int pos = 6;
1003     uint16_t length;
1004     avrcp_pdu_id_t   pdu_id;
1005     // connection->data_len = 0;
1006     uint8_t offset;
1007     uint8_t operand;
1008     uint16_t event_mask;
1009     avrcp_operation_id_t operation_id;
1010 
1011     switch (opcode){
1012         case AVRCP_CMD_OPCODE_UNIT_INFO:
1013             avrcp_target_unit_info(connection);
1014             break;
1015         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:
1016             if ((size - pos) < 3) return;
1017             // page: packet[pos] >> 4,
1018             offset =  4 * (packet[pos]>>4);
1019             // extension code (fixed 7) = packet[pos] & 0x0F
1020             // 4 bytes paga data, all 0xFF
1021             avrcp_target_subunit_info(connection, offset);
1022             break;
1023 
1024         case AVRCP_CMD_OPCODE_PASS_THROUGH:
1025             if (size < 8) return;
1026             log_info("AVRCP_OPERATION_ID 0x%02x, operands length %d", packet[6], packet[7]);
1027             operation_id = (avrcp_operation_id_t) (packet[6] & 0x7f);
1028             operand = 0;
1029             if ((packet[7] >= 1) && (size >= 9)){
1030                 operand = packet[8];
1031             }
1032 
1033             if (avcrp_operation_id_is_valid(operation_id)){
1034                 bool button_pressed = (packet[6] & 0x80) == 0;
1035 
1036                 avrcp_target_operation_accepted(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], operand);
1037                 avrcp_target_emit_operation(avrcp_target_context.avrcp_callback, connection->avrcp_cid,
1038                                                 operation_id, button_pressed, packet[7], operand);
1039             } else {
1040                 avrcp_target_operation_not_implemented(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], operand);
1041             }
1042             break;
1043 
1044 
1045         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
1046 
1047             if (size < 13) return;
1048 
1049             // pos = 6 - company id
1050             (void)memcpy(connection->message_body, &packet[pos], 3);
1051             // connection->data_len = 3;
1052             pos += 3;
1053             // pos = 9
1054             pdu_id = (avrcp_pdu_id_t) packet[pos++];
1055             // 1 - reserved
1056             pos++;
1057             // 2-3 param length,
1058             length = big_endian_read_16(packet, pos);
1059             pos += 2;
1060             // pos = 13
1061             switch (pdu_id){
1062                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:{
1063                     if ((pos + 2) > size) return;
1064                     bool ok = length == 4;
1065                     if (avrcp_target_context.set_addressed_player_callback != NULL){
1066                         uint16_t player_id = big_endian_read_16(packet, pos);
1067                         ok = avrcp_target_context.set_addressed_player_callback(player_id);
1068                     }
1069                     if (ok){
1070                         avrcp_target_vendor_dependent_response_accept(connection, pdu_id, AVRCP_STATUS_SUCCESS);
1071                     } else {
1072                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_PLAYER_ID);
1073                     }
1074                     break;
1075                 }
1076                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
1077                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos];
1078                     switch (capability_id){
1079                         case AVRCP_CAPABILITY_ID_EVENT:
1080                              avrcp_target_response_vendor_dependent_supported_events(connection);
1081                             break;
1082                         case AVRCP_CAPABILITY_ID_COMPANY:
1083                             avrcp_target_response_vendor_dependent_supported_companies(connection);
1084                             break;
1085                         default:
1086                             avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
1087                             break;
1088                     }
1089                     break;
1090                 }
1091                 case AVRCP_PDU_ID_GET_PLAY_STATUS:
1092                     avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_PLAY_STATUS_QUERY);
1093                     break;
1094                 case AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE:
1095                     if ((pos + 1) > size) return;
1096                     connection->message_body[0] = packet[pos];
1097                     connection->target_abort_continue_response = true;
1098                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1099                     break;
1100                 case AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE:
1101                     if ((pos + 1) > size) return;
1102                     if (packet[pos] != AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES){
1103                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
1104                         return;
1105                     }
1106                     connection->target_now_playing_info_response = true;
1107                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1108                     break;
1109                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
1110                     if ((pos + 9) > size) return;
1111                     uint8_t play_identifier[8];
1112                     memset(play_identifier, 0, 8);
1113                     if (memcmp(&packet[pos], play_identifier, 8) != 0) {
1114                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
1115                         return;
1116                     }
1117                     pos += 8;
1118                     uint8_t attribute_count = packet[pos++];
1119                     connection->next_attr_id = AVRCP_MEDIA_ATTR_NONE;
1120                     if (!attribute_count){
1121                         connection->next_attr_id = AVRCP_MEDIA_ATTR_TITLE;
1122                         connection->target_now_playing_info_attr_bitmap = 0xFE;
1123                     } else {
1124                         int i;
1125                         connection->next_attr_id = AVRCP_MEDIA_ATTR_TITLE;
1126                         connection->target_now_playing_info_attr_bitmap = 0;
1127                         if ((pos + attribute_count * 4) > size) return;
1128                         for (i=0; i < attribute_count; i++){
1129                             uint32_t attr_id = big_endian_read_32(packet, pos);
1130                             connection->target_now_playing_info_attr_bitmap |= (1 << attr_id);
1131                             pos += 4;
1132                         }
1133                     }
1134                     log_info("target_now_playing_info_attr_bitmap 0x%02x", connection->target_now_playing_info_attr_bitmap);
1135                     connection->target_now_playing_info_response = true;
1136                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1137                     break;
1138                 }
1139                 case AVRCP_PDU_ID_REGISTER_NOTIFICATION:{
1140                     if ((pos + 1) > size) return;
1141                     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) packet[pos];
1142 
1143                     avrcp_target_set_transaction_label_for_notification(connection, event_id, connection->transaction_id);
1144 
1145                     if (event_id < AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED ||
1146                         event_id > AVRCP_NOTIFICATION_EVENT_MAX_VALUE){
1147                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
1148                         return;
1149                     }
1150 
1151                     switch (event_id){
1152                         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:
1153                         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
1154                         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:
1155                         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_END:
1156                         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_START:
1157                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_POS_CHANGED:
1158                         case AVRCP_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED:
1159                         case AVRCP_NOTIFICATION_EVENT_MAX_VALUE:
1160                             avrcp_target_response_vendor_dependent_not_implemented(connection, pdu_id, event_id);
1161                             return;
1162                         default:
1163                             break;
1164                     }
1165 
1166                     event_mask = (1 << event_id);
1167                     connection->notifications_enabled |= event_mask;
1168 
1169                     switch (event_id){
1170                         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:
1171                             if (connection->target_track_selected){
1172                                 avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_SELECTED, 8);
1173                             } else {
1174                                 avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_NOT_SELECTED, 8);
1175                             }
1176                             break;
1177                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:
1178                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, (const uint8_t *)&connection->target_playback_status, 1);
1179                             break;
1180                         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:
1181                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, NULL, 0);
1182                             break;
1183                         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:
1184                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, (const uint8_t *)&connection->target_absolute_volume, 1);
1185                             break;
1186                         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:
1187                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, (const uint8_t *)&connection->target_battery_status, 1);
1188                             break;
1189                         case AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED:
1190                             avrcp_target_response_addressed_player_changed_interim(connection, pdu_id, event_id);
1191                             return;
1192                         default:
1193                             btstack_assert(false);
1194                             return;
1195                     }
1196                     break;
1197                 }
1198                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME: {
1199                     if ( (length != 1) || ((pos + 1) > size)){
1200                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
1201                         break;
1202                     }
1203 
1204                     uint8_t absolute_volume = packet[pos];
1205                     if (absolute_volume < 0x80){
1206                         connection->target_absolute_volume = absolute_volume;
1207                     }
1208                     avrcp_target_emit_volume_changed(avrcp_target_context.avrcp_callback, connection->avrcp_cid, connection->target_absolute_volume);
1209                     avrcp_target_vendor_dependent_response_accept(connection, pdu_id, connection->target_absolute_volume);
1210                     break;
1211                 }
1212                 default:
1213                     log_info("AVRCP target: unhandled pdu id 0x%02x", pdu_id);
1214                     avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
1215                     break;
1216             }
1217             break;
1218         default:
1219             log_info("AVRCP target: opcode 0x%02x not implemented", avrcp_cmd_opcode(packet,size));
1220             break;
1221     }
1222 }
1223 
1224 static void avrcp_target_notification_init(avrcp_connection_t * connection, avrcp_notification_event_id_t notification_id, uint8_t * value, uint16_t value_len){
1225     btstack_assert((value_len == 0) || (value != NULL));
1226 
1227     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_CHANGED_STABLE, AVRCP_PDU_ID_REGISTER_NOTIFICATION);
1228     connection->transaction_id = avrcp_target_get_transaction_label_for_notification(connection, notification_id);
1229 
1230     connection->data_len = 1 + value_len;
1231     connection->data[0] = notification_id;
1232     if (value_len > 0){
1233         (void)memcpy(connection->data + 1, value, value_len);
1234     }
1235 }
1236 
1237 static void avrcp_target_notification_addressed_player_changed_init(avrcp_connection_t * connection){
1238     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_CHANGED_STABLE, AVRCP_PDU_ID_REGISTER_NOTIFICATION);
1239     connection->transaction_id = avrcp_target_get_transaction_label_for_notification(connection, AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED);
1240 
1241     connection->data_len = 5;
1242     connection->data[0] = AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED;
1243     big_endian_store_16(connection->data, 1, connection->target_addressed_player_id);
1244     big_endian_store_16(connection->data, 3, connection->target_uid_counter);
1245 }
1246 
1247 
1248 static void avrcp_target_reset_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t notification_id){
1249     if (notification_id < AVRCP_NOTIFICATION_EVENT_FIRST_INDEX || notification_id > AVRCP_NOTIFICATION_EVENT_LAST_INDEX){
1250         return;
1251     }
1252     connection->notifications_enabled &= ~(1 << notification_id);
1253     connection->target_notifications_transaction_label[notification_id] = 0;
1254 }
1255 
1256 static void avrcp_request_next_avctp_segment(avrcp_connection_t * connection){
1257     // AVCTP
1258     switch (connection->avctp_packet_type){
1259         case AVCTP_END_PACKET:
1260         case AVCTP_SINGLE_PACKET:
1261             connection->avrcp_frame_bytes_sent = 0;
1262             connection->data_offset = 0;
1263             connection->data_len = 0;
1264             connection->state = AVCTP_CONNECTION_OPENED;
1265             break;
1266         default:
1267             connection->state = AVCTP_W2_SEND_RESPONSE;
1268             avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1269             break;
1270     }
1271 }
1272 
1273 static void avrcp_target_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1274     avrcp_connection_t * connection;
1275     bool send_response = true;
1276     avrcp_notification_event_id_t notification_id = AVRCP_NOTIFICATION_EVENT_NONE;
1277 
1278     switch (packet_type){
1279         case L2CAP_DATA_PACKET:
1280             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, channel);
1281             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1282             return;
1283 
1284         case HCI_EVENT_PACKET:
1285             if (hci_event_packet_get_type(packet) != L2CAP_EVENT_CAN_SEND_NOW){
1286                 return;
1287             }
1288 
1289             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, channel);
1290             if (connection == NULL){
1291                 return;
1292             }
1293 
1294             // START AVCTP
1295             if (connection->target_reject_transport_header){
1296                 connection->target_reject_transport_header = false;
1297                 avctp_send_reject_cmd_wrong_pid(connection);
1298                 connection->state = AVCTP_CONNECTION_OPENED;
1299                 return;
1300             }
1301             // END AVCTP
1302 
1303             if (connection->target_accept_response){
1304                 connection->target_accept_response = false;
1305                 avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_ACCEPTED, AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE);
1306                 break;
1307             }
1308 
1309             if (connection->target_abort_continue_response){
1310                 connection->target_abort_continue_response = false;
1311                 connection->target_now_playing_info_response = false;
1312                 avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_ACCEPTED, AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE);
1313                 break;
1314             }
1315 
1316             if (connection->target_now_playing_info_response){
1317                 connection->target_now_playing_info_response = false;
1318                 avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE, AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES);
1319                 connection->data_len = avrcp_now_playing_info_value_len_with_headers(connection);
1320                 break;
1321             }
1322 
1323             if (connection->target_track_changed){
1324                 connection->target_track_changed = false;
1325                 notification_id = AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED;
1326                 avrcp_target_notification_init(connection, notification_id, connection->target_track_id, 8);
1327                 break;
1328             }
1329 
1330             if (connection->target_playback_status_changed){
1331                 connection->target_playback_status_changed = false;
1332                 notification_id = AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED;
1333                 uint8_t playback_status = (uint8_t) connection->target_playback_status;
1334                 avrcp_target_notification_init(connection, notification_id, &playback_status, 1);
1335                 break;
1336             }
1337 
1338             if (connection->target_playing_content_changed){
1339                 connection->target_playing_content_changed = false;
1340                 notification_id = AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED;
1341                 avrcp_target_notification_init(connection, notification_id, NULL, avrcp_now_playing_info_value_len_with_headers(connection));
1342                 break;
1343             }
1344 
1345             if (connection->target_battery_status_changed){
1346                 connection->target_battery_status_changed = false;
1347                 notification_id = AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED;
1348                 avrcp_target_notification_init(connection, notification_id, (uint8_t *)&connection->target_battery_status, 1);
1349                 break;
1350             }
1351 
1352             if (connection->target_notify_absolute_volume_changed){
1353                 connection->target_notify_absolute_volume_changed = false;
1354                 notification_id = AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED;
1355                 avrcp_target_notification_init(connection, notification_id, &connection->target_absolute_volume, 1);
1356                 break;
1357             }
1358 
1359             if (connection->target_addressed_player_changed){
1360                 connection->target_addressed_player_changed = false;
1361                 notification_id = AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED;
1362                 avrcp_target_notification_addressed_player_changed_init(connection);
1363                 break;
1364             }
1365 
1366             send_response = false;
1367             break;
1368 
1369         default:
1370             return;
1371     }
1372 
1373     if (connection != NULL && (send_response || connection->state == AVCTP_W2_SEND_RESPONSE)){
1374         avrcp_send_response_with_avctp_fragmentation(connection);
1375         avrcp_target_reset_notification(connection, notification_id);
1376         avrcp_request_next_avctp_segment(connection);
1377     }
1378 }
1379 
1380 void avrcp_target_init(void){
1381     avrcp_target_context.role = AVRCP_TARGET;
1382     avrcp_target_context.packet_handler = avrcp_target_packet_handler;
1383     avrcp_register_target_packet_handler(&avrcp_target_packet_handler);
1384 }
1385 
1386 void avrcp_target_deinit(void){
1387     memset(&avrcp_target_context, 0, sizeof(avrcp_context_t));
1388 }
1389 
1390 void avrcp_target_register_packet_handler(btstack_packet_handler_t callback){
1391     btstack_assert(callback != NULL);
1392     avrcp_target_context.avrcp_callback = callback;
1393 }
1394 
1395 void avrcp_target_register_set_addressed_player_handler(bool (*callback)(uint16_t player_id)){
1396     btstack_assert(callback != NULL);
1397     avrcp_target_context.set_addressed_player_callback = callback;
1398 }
1399 
1400 
1401