xref: /btstack/src/classic/avrcp_target.c (revision 08a78038ba366a6a2a2df8fea05d5123880fdff2)
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(false, 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 = snprintf(buffer, sizeof(buffer), "%" PRIu32, connection->target_track_nr);
140             break;
141         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
142             str_len = snprintf(buffer, sizeof(buffer), "%" PRIu32, connection->target_total_tracks);
143             break;
144         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
145             str_len = snprintf(buffer, sizeof(buffer), "%" 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 		// "4294967296" = 10 chars + \0
185         connection->attribute_value_len = snprintf((char *)connection->attribute_value, 11, "%" PRIu32, value);
186         connection->attribute_value_offset = 0;
187     }
188     *num_bytes_to_copy = connection->attribute_value_len - connection->attribute_value_offset;
189     return connection->attribute_value + connection->attribute_value_offset;
190 }
191 
192 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){
193     switch (attr_id){
194         case AVRCP_MEDIA_ATTR_TRACK:
195             return avrcp_get_attribute_value_from_u32(connection, connection->target_track_nr, num_bytes_to_copy);
196         case AVRCP_MEDIA_ATTR_TOTAL_NUM_ITEMS:
197             return avrcp_get_attribute_value_from_u32(connection, connection->target_total_tracks, num_bytes_to_copy);
198         case AVRCP_MEDIA_ATTR_SONG_LENGTH_MS:
199             return avrcp_get_attribute_value_from_u32(connection, connection->target_song_length_ms, num_bytes_to_copy);
200         default:
201             break;
202     }
203     int attr_index = attr_id - 1;
204     if (connection->attribute_value_len == 0){
205         connection->attribute_value_len = avrcp_now_playing_info_attr_id_value_len(connection, attr_id);
206         connection->attribute_value_offset = 0;
207     }
208     *num_bytes_to_copy = connection->target_now_playing_info[attr_index].len - connection->attribute_value_offset;
209     return (uint8_t *) (connection->target_now_playing_info[attr_index].value + connection->attribute_value_offset);
210 }
211 
212 // TODO Review
213 static uint16_t avrcp_store_avctp_now_playing_info_fragment(avrcp_connection_t * connection, uint16_t packet_size, uint8_t * packet){
214     uint16_t num_free_bytes = packet_size;
215 
216     uint16_t bytes_stored = 0;
217 
218     while ((num_free_bytes > 0) && (connection->next_attr_id <= AVRCP_MEDIA_ATTR_SONG_LENGTH_MS)){
219         if ((connection->target_now_playing_info_attr_bitmap & (1 << (uint8_t)connection->next_attr_id)) == 0) {
220             connection->next_attr_id = (avrcp_media_attribute_id_t) (((int) connection->next_attr_id) + 1);
221             continue;
222         }
223 
224         // prepare attribute value
225         uint16_t num_bytes_to_copy;
226         uint8_t * attr_value_with_offset = avrcp_get_next_value_fragment_for_attribute_id(connection,
227                                                                                           connection->next_attr_id,
228                                                                                           &num_bytes_to_copy);
229 
230         // store header
231         if (connection->attribute_value_offset == 0){
232             // pack the whole attribute value header
233             if (connection->parser_attribute_header_pos == 0) {
234                 avrcp_target_pack_single_element_header(connection->parser_attribute_header, connection->next_attr_id,
235                                                         connection->attribute_value_len);
236             }
237         }
238 
239         if (connection->parser_attribute_header_pos < AVRCP_ATTRIBUTE_HEADER_LEN){
240             uint16_t num_header_bytes_to_store = btstack_min(num_free_bytes, AVRCP_ATTRIBUTE_HEADER_LEN - connection->parser_attribute_header_pos);
241             memcpy(packet + bytes_stored, connection->parser_attribute_header + connection->parser_attribute_header_pos, num_header_bytes_to_store);
242             connection->parser_attribute_header_pos += num_header_bytes_to_store;
243             bytes_stored += num_header_bytes_to_store;
244             num_free_bytes -= num_header_bytes_to_store;
245             connection->data_offset += num_header_bytes_to_store;
246 
247             if (num_free_bytes == 0){
248                 continue;
249             }
250         }
251 
252         // store value
253         uint16_t num_attr_value_bytes_to_store = btstack_min(num_free_bytes, connection->attribute_value_len - connection->attribute_value_offset);
254         memcpy(packet + bytes_stored, attr_value_with_offset, num_attr_value_bytes_to_store);
255         bytes_stored   += num_attr_value_bytes_to_store;
256         num_free_bytes -= num_attr_value_bytes_to_store;
257         connection->attribute_value_offset += num_attr_value_bytes_to_store;
258         connection->data_offset += num_attr_value_bytes_to_store;
259 
260         if (connection->attribute_value_offset == connection->attribute_value_len){
261             // C++ compatible version of connection->next_attr_id++
262             connection->next_attr_id = (avrcp_media_attribute_id_t) (((int) connection->next_attr_id) + 1);
263             connection->attribute_value_offset = 0;
264             connection->attribute_value_len = 0;
265             connection->parser_attribute_header_pos = 0;
266         }
267     }
268     return bytes_stored;
269 }
270 
271 static void avrcp_send_response_with_avctp_fragmentation(avrcp_connection_t * connection){
272     l2cap_reserve_packet_buffer();
273     uint8_t * packet = l2cap_get_outgoing_buffer();
274 
275     // transport header
276     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
277 
278     uint16_t max_payload_size;
279     connection->avctp_packet_type = avctp_get_packet_type(connection, &max_payload_size);
280     connection->avrcp_packet_type = avrcp_get_packet_type(connection);
281 
282     // AVCTP header
283     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
284     uint16_t pos = 0;
285     packet[pos++] = (connection->transaction_id << 4) | (connection->avctp_packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
286 
287     uint16_t param_len = connection->data_len;
288 
289     if (connection->avctp_packet_type == AVCTP_START_PACKET){
290         uint16_t max_frame_size = btstack_min(connection->l2cap_mtu, AVRCP_MAX_AV_C_MESSAGE_FRAME_SIZE);
291         // first packet: max_payload_size
292         // rest packets
293         uint16_t num_payload_bytes = param_len - max_payload_size;
294         uint16_t frame_size_for_continue_packet = max_frame_size - avctp_get_num_bytes_for_header(AVCTP_CONTINUE_PACKET);
295         uint16_t num_avctp_packets = (num_payload_bytes + frame_size_for_continue_packet - 1)/frame_size_for_continue_packet + 1;
296 		btstack_assert(num_avctp_packets <= 255);
297         packet[pos++] = (uint8_t) num_avctp_packets;
298     }
299 
300     uint16_t bytes_stored = 0;
301     uint8_t i;
302 
303     switch (connection->avctp_packet_type) {
304         case AVCTP_SINGLE_PACKET:
305         case AVCTP_START_PACKET:
306             // Profile IDentifier (PID)
307             packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
308             packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
309 
310             // AVRCP message
311             // command_type
312             packet[pos++] = connection->command_type;
313             // subunit_type | subunit ID
314             packet[pos++] = (connection->subunit_type << 3) | connection->subunit_id;
315             // opcode
316             packet[pos++] = (uint8_t) connection->command_opcode;
317 
318             switch (connection->command_opcode) {
319                 case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
320                     big_endian_store_24(packet, pos, connection->company_id);
321                     pos += 3;
322                     packet[pos++] = connection->pdu_id;
323                     // AVRCP packet type
324 
325                     packet[pos++] = (uint8_t)connection->avrcp_packet_type;
326                     // parameter length
327                     big_endian_store_16(packet, pos, param_len);
328                     pos += 2;
329 
330                     switch (connection->pdu_id) {
331                         // message is small enough to fit the single packet, no need for extra check
332                         case AVRCP_PDU_ID_GET_CAPABILITIES:
333                             // capability ID
334                             packet[pos++] = connection->data[0];
335                             // num_capabilities
336                             packet[pos++] = connection->data[1];
337 
338                             switch ((avrcp_capability_id_t) connection->data[0]) {
339                                 case AVRCP_CAPABILITY_ID_EVENT:
340                                     for (i = (uint8_t) AVRCP_NOTIFICATION_EVENT_FIRST_INDEX;
341                                          i < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; i++) {
342                                         if ((connection->notifications_supported_by_target & (1 << i)) == 0) {
343                                             continue;
344                                         }
345                                         packet[pos++] = i;
346                                     }
347                                     break;
348                                 case AVRCP_CAPABILITY_ID_COMPANY:
349                                     // use Bluetooth SIG as default company
350                                     for (i = 0; i < connection->data[1]; i++) {
351                                         little_endian_store_24(packet, pos,
352                                                                connection->target_supported_companies[i]);
353                                         pos += 3;
354                                     }
355                                     break;
356                                 default:
357                                     // error response
358                                     break;
359                             }
360                             l2cap_send_prepared(connection->l2cap_signaling_cid, pos);
361                             return;
362 
363                         case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:
364                             packet[pos++] = count_set_bits_uint32(connection->target_now_playing_info_attr_bitmap);
365                             max_payload_size--;
366 
367                             bytes_stored = avrcp_store_avctp_now_playing_info_fragment(connection, max_payload_size, packet + pos);
368 
369                             connection->avrcp_frame_bytes_sent += bytes_stored + pos;
370                             l2cap_send_prepared(connection->l2cap_signaling_cid, pos + bytes_stored);
371                             return;
372 
373                         default:
374                             // error response and other OPCODEs
375                             break;
376                     }
377                     break;
378 
379                 case AVRCP_CMD_OPCODE_PASS_THROUGH:
380                     packet[pos++] = connection->operation_id;
381                     // parameter length
382                     packet[pos++] = (uint8_t) connection->data_len;
383                     pos += 2;
384                     break;
385                 case AVRCP_CMD_OPCODE_UNIT_INFO:
386                     break;
387                 case AVRCP_CMD_OPCODE_SUBUNIT_INFO:
388                     break;
389                 default:
390                     btstack_assert(false);
391                     return;
392             }
393             break;
394         case AVCTP_CONTINUE_PACKET:
395         case AVCTP_END_PACKET:
396             switch (connection->pdu_id) {
397                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:
398                     bytes_stored = avrcp_store_avctp_now_playing_info_fragment(connection, max_payload_size, packet + pos);
399 
400                     connection->avrcp_frame_bytes_sent += bytes_stored + pos;
401                     l2cap_send_prepared(connection->l2cap_signaling_cid, pos + bytes_stored);
402                     return;
403 
404                 default:
405                     break;
406             }
407             break;
408         default:
409             btstack_assert(false);
410             return;
411     }
412 
413     // compare number of bytes to store with the remaining buffer size
414     uint16_t bytes_to_copy = btstack_min(connection->data_len - connection->data_offset, max_payload_size - pos);
415 
416     (void)memcpy(packet + pos, &connection->data[connection->data_offset], bytes_to_copy);
417     pos += bytes_to_copy;
418     connection->data_offset += bytes_to_copy;
419     connection->avrcp_frame_bytes_sent += pos;
420 
421     l2cap_send_prepared(connection->l2cap_signaling_cid, pos);
422 }
423 
424 static void avctp_send_reject_cmd_wrong_pid(avrcp_connection_t * connection){
425     l2cap_reserve_packet_buffer();
426     uint8_t * packet = l2cap_get_outgoing_buffer();
427 
428     // AVCTP header
429     // transport header : transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
430     packet[0] = (connection->transaction_id << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_RESPONSE_FRAME << 1) | 1;
431     big_endian_store_16(packet, 1, connection->message_body[0]);
432     l2cap_send_prepared(connection->l2cap_signaling_cid, 3);
433 }
434 
435 static void avrcp_target_custom_command_data_init(avrcp_connection_t * connection,
436     avrcp_command_opcode_t opcode, avrcp_command_type_t command_type,
437     avrcp_subunit_type_t subunit_type, avrcp_subunit_id_t subunit_id,
438     avrcp_pdu_id_t pdu_id, uint32_t company_id){
439 
440     connection->command_opcode = opcode;
441     connection->command_type = command_type;
442     connection->subunit_type = subunit_type;
443     connection->subunit_id = subunit_id;
444     connection->company_id = company_id << 16;
445     connection->pdu_id = pdu_id;
446     connection->data = NULL;
447     connection->data_offset = 0;
448     connection->data_len = 0;
449     connection->avrcp_frame_bytes_sent = 0;
450 }
451 
452 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){
453     connection->command_opcode = AVRCP_CMD_OPCODE_VENDOR_DEPENDENT;
454     connection->subunit_type   = AVRCP_SUBUNIT_TYPE_PANEL;
455     connection->subunit_id     = AVRCP_SUBUNIT_ID;
456     connection->company_id     = BT_SIG_COMPANY_ID;
457 
458     connection->command_type = command_type;
459     connection->pdu_id = pdu_id;
460     connection->data = connection->message_body;
461     connection->data_offset = 0;
462     connection->data_len = 0;
463     connection->avrcp_frame_bytes_sent = 0;
464 }
465 
466 static void avrcp_target_pass_through_command_data_init(avrcp_connection_t * connection, avrcp_command_type_t command_type, avrcp_operation_id_t opid){
467     connection->command_opcode = AVRCP_CMD_OPCODE_PASS_THROUGH;
468     connection->subunit_type   = AVRCP_SUBUNIT_TYPE_PANEL;
469     connection->subunit_id     = AVRCP_SUBUNIT_ID;
470 
471     connection->command_type = command_type;
472     connection->company_id = 0;
473     connection->pdu_id = AVRCP_PDU_ID_UNDEFINED;
474     connection->operation_id = opid;
475 
476     connection->data = connection->message_body;
477     connection->data_offset = 0;
478     connection->data_len = 0;
479     connection->avrcp_frame_bytes_sent = 0;
480 }
481 
482 
483 static uint8_t avrcp_target_vendor_dependent_response_accept(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, uint8_t status){
484     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_ACCEPTED, pdu_id);
485     connection->data_len = 1;
486     connection->data[0] = status;
487 
488     connection->target_accept_response = true;
489     connection->state = AVCTP_W2_SEND_RESPONSE;
490     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
491     return ERROR_CODE_SUCCESS;
492 }
493 
494 static uint8_t avrcp_target_response_vendor_dependent_reject(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, avrcp_status_code_t status){
495     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_REJECTED, pdu_id);
496     connection->data_len = 1;
497     connection->data[0] = status;
498 
499     connection->state = AVCTP_W2_SEND_RESPONSE;
500     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
501     return ERROR_CODE_SUCCESS;
502 }
503 
504 static uint8_t avrcp_target_response_vendor_dependent_not_implemented(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, uint8_t event_id){
505     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_NOT_IMPLEMENTED, pdu_id);
506     connection->data_len = 1;
507     connection->data[0] = event_id;
508 
509     connection->state = AVCTP_W2_SEND_RESPONSE;
510     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
511     return ERROR_CODE_SUCCESS;
512 }
513 
514 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){
515     btstack_assert(value_len + 1 < AVRCP_MAX_COMMAND_PARAMETER_LENGTH);
516     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_INTERIM, pdu_id);
517     connection->data_len = 1 + value_len;
518     connection->data[0] = event_id;
519 
520     if (value && (value_len > 0)){
521         (void)memcpy(connection->data + 1, value, value_len);
522     }
523 
524     connection->state = AVCTP_W2_SEND_RESPONSE;
525     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
526     return ERROR_CODE_SUCCESS;
527 }
528 
529 static uint8_t avrcp_target_response_addressed_player_changed_interim(avrcp_connection_t * connection, avrcp_pdu_id_t pdu_id, uint8_t event_id){
530     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_INTERIM, pdu_id);
531 
532     connection->data_len = 5;
533     connection->data[0] = event_id;
534     big_endian_store_16(connection->data, 1, connection->target_addressed_player_id);
535     big_endian_store_16(connection->data, 3, connection->target_uid_counter);
536 
537     connection->state = AVCTP_W2_SEND_RESPONSE;
538     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
539     return ERROR_CODE_SUCCESS;
540 }
541 
542 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){
543     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
544     if (!connection){
545         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
546     }
547     avrcp_target_pass_through_command_data_init(connection, ctype, opid);
548 
549     if (operands_length == 1){
550         connection->data_len = 1;
551         connection->message_body[0] = operand;
552     }
553 
554     connection->state = AVCTP_W2_SEND_RESPONSE;
555     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
556     return ERROR_CODE_SUCCESS;
557 }
558 
559 uint8_t avrcp_target_operation_rejected(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
560     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_REJECTED, opid, operands_length, operand);
561 }
562 
563 uint8_t avrcp_target_operation_accepted(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
564     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_ACCEPTED, opid, operands_length, operand);
565 }
566 
567 uint8_t avrcp_target_operation_not_implemented(uint16_t avrcp_cid, avrcp_operation_id_t opid, uint8_t operands_length, uint8_t operand){
568     return avrcp_target_pass_through_response(avrcp_cid, AVRCP_CTYPE_RESPONSE_ACCEPTED, opid, operands_length, operand);
569 }
570 
571 uint8_t avrcp_target_set_unit_info(uint16_t avrcp_cid, avrcp_subunit_type_t unit_type, uint32_t company_id){
572     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
573     if (!connection){
574         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
575     }
576     connection->target_unit_type = unit_type;
577     connection->company_id = company_id;
578     return ERROR_CODE_SUCCESS;
579 }
580 
581 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){
582     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
583     if (!connection){
584         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
585     }
586     connection->target_subunit_info_type = subunit_type;
587     connection->target_subunit_info_data = subunit_info_data;
588     connection->target_subunit_info_data_size = subunit_info_data_size;
589     return ERROR_CODE_SUCCESS;
590 }
591 
592 static uint8_t avrcp_target_unit_info(avrcp_connection_t * connection){
593     if (connection->state != AVCTP_CONNECTION_OPENED){
594         return ERROR_CODE_COMMAND_DISALLOWED;
595     }
596 
597     avrcp_target_custom_command_data_init(connection,
598                                           AVRCP_CMD_OPCODE_UNIT_INFO, AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE,
599                                           AVRCP_SUBUNIT_TYPE_UNIT, AVRCP_SUBUNIT_ID_IGNORE, AVRCP_PDU_ID_UNDEFINED,
600                                           connection->company_id);
601 
602     uint8_t unit = 0;
603     connection->data = connection->message_body;
604     connection->data_len = 5;
605     connection->data[0] = 0x07;
606     connection->data[1] = (connection->target_unit_type << 4) | unit;
607     // company id is 3 bytes long
608     big_endian_store_24(connection->data, 2, connection->company_id);
609 
610     connection->state = AVCTP_W2_SEND_RESPONSE;
611     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
612     return ERROR_CODE_SUCCESS;
613 }
614 
615 static uint8_t avrcp_target_subunit_info(avrcp_connection_t * connection, uint8_t offset){
616     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
617     if (offset >= 32) return AVRCP_STATUS_INVALID_PARAMETER;
618 
619     avrcp_target_custom_command_data_init(connection, AVRCP_CMD_OPCODE_SUBUNIT_INFO,
620                                           AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE,
621                                           AVRCP_SUBUNIT_TYPE_UNIT, AVRCP_SUBUNIT_ID_IGNORE, AVRCP_PDU_ID_UNDEFINED,
622                                           connection->company_id);
623 
624     uint8_t page = offset / 4;
625     uint8_t extension_code = 7;
626     connection->data = connection->message_body;
627     connection->data_len = 5;
628     connection->data[0] = (page << 4) | extension_code;
629 
630     // mark non-existent entries with 0xff
631     memset(&connection->message_body[1], 0xFF, 4);
632     if ((connection->data != NULL) && (offset < connection->target_subunit_info_data_size)){
633         uint8_t bytes_to_copy = btstack_min(connection->target_subunit_info_data_size - offset, 4);
634         memcpy(&connection->data[1], &connection->target_subunit_info_data[offset], bytes_to_copy);
635     }
636 
637     connection->state = AVCTP_W2_SEND_RESPONSE;
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 
645     uint8_t event_id;
646     uint8_t num_events = 0;
647     for (event_id = (uint8_t) AVRCP_NOTIFICATION_EVENT_FIRST_INDEX; event_id < (uint8_t) AVRCP_NOTIFICATION_EVENT_LAST_INDEX; event_id++){
648         if ((connection->notifications_supported_by_target & (1 << event_id)) == 0){
649             continue;
650         }
651         num_events++;
652     }
653 
654     connection->data[0] = AVRCP_CAPABILITY_ID_EVENT;
655     connection->data[1] = num_events;
656     connection->data_len = 2 + num_events;
657 
658     // fill the data later directly to the L2CAP outgoing buffer
659     connection->state = AVCTP_W2_SEND_RESPONSE;
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 
667     connection->data[0] = AVRCP_CAPABILITY_ID_COMPANY;
668     if (connection->target_supported_companies_num == 0){
669         connection->target_supported_companies_num = 1;
670         connection->target_supported_companies = default_companies;
671     }
672 
673     connection->data[1] = connection->target_supported_companies_num;
674     connection->data_len = 2 + connection->data[1] * 3;
675 
676     // fill the data later directly to the L2CAP outgoing buffer and
677     // use Bluetooth SIG as default company
678     connection->state = AVCTP_W2_SEND_RESPONSE;
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 	uint16_t value_len = (uint16_t)strlen(value);
733 	btstack_assert(value_len <= 255);
734 	connection->target_now_playing_info[index].value = (uint8_t*)value;
735     connection->target_now_playing_info[index].len   = value_len;
736     return ERROR_CODE_SUCCESS;
737 }
738 
739 uint8_t avrcp_target_set_playback_status(uint16_t avrcp_cid, avrcp_playback_status_t playback_status){
740     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
741     if (!connection){
742         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
743     }
744     if (connection->target_playback_status == playback_status){
745         return ERROR_CODE_SUCCESS;
746     }
747 
748     connection->target_playback_status = playback_status;
749     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED)) {
750         connection->target_playback_status_changed = true;
751         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
752     }
753     return ERROR_CODE_SUCCESS;
754 }
755 
756 static void avrcp_target_register_track_changed(avrcp_connection_t * connection, const uint8_t * track_id){
757     if (track_id == NULL){
758         memset(connection->target_track_id, 0xFF, 8);
759         connection->target_track_selected = false;
760     } else {
761         (void)memcpy(connection->target_track_id, track_id, 8);
762         connection->target_track_selected = true;
763     }
764 
765     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED)) {
766         connection->target_track_changed = true;
767         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
768     }
769 }
770 
771 uint8_t avrcp_target_track_changed(uint16_t avrcp_cid, uint8_t * track_id){
772     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
773     if (!connection){
774         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
775     }
776     avrcp_target_register_track_changed(connection, track_id);
777     return ERROR_CODE_SUCCESS;
778 }
779 
780 uint8_t avrcp_target_set_now_playing_info(uint16_t avrcp_cid, const avrcp_track_t * current_track, uint16_t total_tracks){
781     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
782     if (!connection){
783         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
784     }
785     if (!current_track){
786         return ERROR_CODE_COMMAND_DISALLOWED;
787     }
788 
789     (void)memcpy(connection->target_track_id, current_track->track_id, 8);
790     connection->target_song_length_ms = current_track->song_length_ms;
791     connection->target_track_nr = current_track->track_nr;
792     connection->target_total_tracks = total_tracks;
793     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_TITLE, current_track->title);
794     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ARTIST, current_track->artist);
795     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_ALBUM, current_track->album);
796     avrcp_target_store_media_attr(connection, AVRCP_MEDIA_ATTR_GENRE, current_track->genre);
797 
798     avrcp_target_register_track_changed(connection, current_track->track_id);
799     return ERROR_CODE_SUCCESS;
800 }
801 
802 
803 uint8_t avrcp_target_playing_content_changed(uint16_t avrcp_cid){
804     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
805     if (!connection){
806         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
807     }
808     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED)) {
809         connection->target_playing_content_changed = true;
810         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
811     }
812     return ERROR_CODE_SUCCESS;
813 }
814 
815 uint8_t avrcp_target_addressed_player_changed(uint16_t avrcp_cid, uint16_t player_id, uint16_t uid_counter){
816     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
817     if (!connection){
818         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
819     }
820 
821     if (connection->target_addressed_player_id == player_id){
822         return ERROR_CODE_SUCCESS;
823     }
824 
825     connection->target_uid_counter = uid_counter;
826     connection->target_addressed_player_id = player_id;
827 
828     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED)) {
829         connection->target_addressed_player_changed = true;
830         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
831     }
832     return ERROR_CODE_SUCCESS;
833 }
834 
835 uint8_t avrcp_target_battery_status_changed(uint16_t avrcp_cid, avrcp_battery_status_t battery_status){
836     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
837     if (!connection){
838         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
839     }
840     if (connection->target_battery_status == battery_status){
841         return ERROR_CODE_SUCCESS;
842     }
843 
844     connection->target_battery_status = battery_status;
845 
846     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED)) {
847         connection->target_battery_status_changed = true;
848         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
849     }
850     return ERROR_CODE_SUCCESS;
851 }
852 
853 uint8_t avrcp_target_adjust_absolute_volume(uint16_t avrcp_cid, uint8_t absolute_volume){
854     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
855     if (!connection){
856         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
857     }
858 
859     connection->target_absolute_volume = absolute_volume;
860     return ERROR_CODE_SUCCESS;
861 }
862 
863 uint8_t avrcp_target_volume_changed(uint16_t avrcp_cid, uint8_t absolute_volume){
864     avrcp_connection_t * connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
865     if (!connection){
866         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
867     }
868     if (connection->target_absolute_volume == absolute_volume){
869         return ERROR_CODE_SUCCESS;
870     }
871 
872     connection->target_absolute_volume = absolute_volume;
873 
874     if (connection->notifications_enabled & (1 << AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED )) {
875         connection->target_notify_absolute_volume_changed = true;
876         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
877     }
878     return ERROR_CODE_SUCCESS;
879 }
880 
881 static void avrcp_target_set_transaction_label_for_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t notification, uint8_t transaction_label){
882     if (notification > AVRCP_NOTIFICATION_EVENT_MAX_VALUE) return;
883     connection->target_notifications_transaction_label[notification] = transaction_label;
884 }
885 
886 static uint8_t avrcp_target_get_transaction_label_for_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t notification){
887     if (notification > AVRCP_NOTIFICATION_EVENT_MAX_VALUE) return 0;
888     return connection->target_notifications_transaction_label[notification];
889 }
890 
891 static bool avcrp_operation_id_is_valid(avrcp_operation_id_t operation_id){
892     if (operation_id < AVRCP_OPERATION_ID_RESERVED_1) return true;
893 
894     if (operation_id < AVRCP_OPERATION_ID_0) return false;
895     if (operation_id < AVRCP_OPERATION_ID_RESERVED_2) 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_CHANNEL_UP) return false;
901     if (operation_id < AVRCP_OPERATION_ID_RESERVED_3) return true;
902 
903     if (operation_id < AVRCP_OPERATION_ID_SKIP) return false;
904     if (operation_id == AVRCP_OPERATION_ID_SKIP) return true;
905 
906     if (operation_id < AVRCP_OPERATION_ID_POWER) return false;
907     if (operation_id < AVRCP_OPERATION_ID_RESERVED_4) return true;
908 
909     if (operation_id < AVRCP_OPERATION_ID_ANGLE) return false;
910     if (operation_id < AVRCP_OPERATION_ID_RESERVED_5) return true;
911 
912     if (operation_id < AVRCP_OPERATION_ID_F1) return false;
913     if (operation_id < AVRCP_OPERATION_ID_RESERVED_6) return true;
914 
915     return false;
916 }
917 
918 
919 #ifdef ENABLE_AVCTP_FRAGMENTATION
920 static void avctp_reassemble_message(avrcp_connection_t * connection, avctp_packet_type_t packet_type, uint8_t *packet, uint16_t size){
921     // after header (transaction label and packet type)
922     uint16_t pos;
923     uint16_t bytes_to_store;
924 
925     switch (packet_type){
926         case AVCTP_START_PACKET:
927             if (size < 2) return;
928 
929             // store header
930             pos = 0;
931             connection->avctp_reassembly_buffer[pos] = packet[pos];
932             pos++;
933             connection->avctp_reassembly_size = pos;
934 
935             // NOTE: num packets not needed for reassembly, ignoring it does not pose security risk -> no need to store it
936             pos++;
937 
938             // PID in reassembled packet is at offset 1, it will be read later after the avctp_reassemble_message with AVCTP_END_PACKET is called
939 
940             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
941             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
942             connection->avctp_reassembly_size += bytes_to_store;
943             break;
944 
945         case AVCTP_CONTINUE_PACKET:
946         case AVCTP_END_PACKET:
947             if (size < 1) return;
948 
949             // store remaining data, ignore header
950             pos = 1;
951             bytes_to_store = btstack_min(size - pos, sizeof(connection->avctp_reassembly_buffer) - connection->avctp_reassembly_size);
952             memcpy(&connection->avctp_reassembly_buffer[connection->avctp_reassembly_size], &packet[pos], bytes_to_store);
953             connection->avctp_reassembly_size += bytes_to_store;
954             break;
955 
956         default:
957             return;
958     }
959 }
960 #endif
961 
962 static void avrcp_handle_l2cap_data_packet_for_signaling_connection(avrcp_connection_t * connection, uint8_t * packet, uint16_t size){
963     uint8_t avctp_header = packet[0];
964     connection->transaction_id = avctp_header >> 4;
965 
966     avctp_packet_type_t avctp_packet_type = (avctp_packet_type_t) ((avctp_header & 0x0F) >> 2);
967     switch (avctp_packet_type){
968         case AVCTP_SINGLE_PACKET:
969             break;
970 
971 #ifdef ENABLE_AVCTP_FRAGMENTATION
972         case AVCTP_START_PACKET:
973         case AVCTP_CONTINUE_PACKET:
974             avctp_reassemble_message(connection, avctp_packet_type, packet, size);
975             return;
976 
977         case AVCTP_END_PACKET:
978             avctp_reassemble_message(connection, avctp_packet_type, packet, size);
979 
980             packet = connection->avctp_reassembly_buffer;
981             size   = connection->avctp_reassembly_size;
982             break;
983 #endif
984         default:
985             return;
986     }
987 
988     if (size < 6u) return;
989 
990     uint16_t pid = big_endian_read_16(packet, 1);
991 
992     if (pid != BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL){
993         log_info("Invalid pid 0x%02x, expected 0x%02x", pid, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
994         connection->target_reject_transport_header = true;
995         connection->target_invalid_pid = pid;
996         connection->state = AVCTP_W2_SEND_RESPONSE;
997         avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
998         return;
999     }
1000 
1001     // avrcp_subunit_type_t subunit_type = (avrcp_subunit_type_t) (packet[4] >> 3);
1002     // avrcp_subunit_id_t   subunit_id   = (avrcp_subunit_id_t) (packet[4] & 0x07);
1003 
1004     avrcp_command_opcode_t opcode = (avrcp_command_opcode_t) avrcp_cmd_opcode(packet,size);
1005 
1006     int pos = 6;
1007     uint16_t length;
1008     avrcp_pdu_id_t   pdu_id;
1009     // connection->data_len = 0;
1010     uint8_t offset;
1011     uint8_t operand;
1012     uint16_t event_mask;
1013     avrcp_operation_id_t operation_id;
1014 
1015     switch (opcode){
1016         case AVRCP_CMD_OPCODE_UNIT_INFO:
1017             avrcp_target_unit_info(connection);
1018             break;
1019         case AVRCP_CMD_OPCODE_SUBUNIT_INFO:
1020             if ((size - pos) < 3) return;
1021             // page: packet[pos] >> 4,
1022             offset =  4 * (packet[pos]>>4);
1023             // extension code (fixed 7) = packet[pos] & 0x0F
1024             // 4 bytes paga data, all 0xFF
1025             avrcp_target_subunit_info(connection, offset);
1026             break;
1027 
1028         case AVRCP_CMD_OPCODE_PASS_THROUGH:
1029             if (size < 8) return;
1030             log_info("AVRCP_OPERATION_ID 0x%02x, operands length %d", packet[6], packet[7]);
1031             operation_id = (avrcp_operation_id_t) (packet[6] & 0x7f);
1032             operand = 0;
1033             if ((packet[7] >= 1) && (size >= 9)){
1034                 operand = packet[8];
1035             }
1036 
1037             if (avcrp_operation_id_is_valid(operation_id)){
1038                 bool button_pressed = (packet[6] & 0x80) == 0;
1039 
1040                 avrcp_target_operation_accepted(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], operand);
1041                 avrcp_target_emit_operation(avrcp_target_context.avrcp_callback, connection->avrcp_cid,
1042                                                 operation_id, button_pressed, packet[7], operand);
1043             } else {
1044                 avrcp_target_operation_not_implemented(connection->avrcp_cid, (avrcp_operation_id_t) packet[6], packet[7], operand);
1045             }
1046             break;
1047 
1048 
1049         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
1050 
1051             if (size < 13) return;
1052 
1053             // pos = 6 - company id
1054             (void)memcpy(connection->message_body, &packet[pos], 3);
1055             // connection->data_len = 3;
1056             pos += 3;
1057             // pos = 9
1058             pdu_id = (avrcp_pdu_id_t) packet[pos++];
1059             // 1 - reserved
1060             pos++;
1061             // 2-3 param length,
1062             length = big_endian_read_16(packet, pos);
1063             pos += 2;
1064             // pos = 13
1065             switch (pdu_id){
1066                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:{
1067                     if ((pos + 2) > size) return;
1068                     bool ok = length == 4;
1069                     if (avrcp_target_context.set_addressed_player_callback != NULL){
1070                         uint16_t player_id = big_endian_read_16(packet, pos);
1071                         ok = avrcp_target_context.set_addressed_player_callback(player_id);
1072                     }
1073                     if (ok){
1074                         avrcp_target_vendor_dependent_response_accept(connection, pdu_id, AVRCP_STATUS_SUCCESS);
1075                     } else {
1076                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_PLAYER_ID);
1077                     }
1078                     break;
1079                 }
1080                 case AVRCP_PDU_ID_GET_CAPABILITIES:{
1081                     avrcp_capability_id_t capability_id = (avrcp_capability_id_t) packet[pos];
1082                     switch (capability_id){
1083                         case AVRCP_CAPABILITY_ID_EVENT:
1084                              avrcp_target_response_vendor_dependent_supported_events(connection);
1085                             break;
1086                         case AVRCP_CAPABILITY_ID_COMPANY:
1087                             avrcp_target_response_vendor_dependent_supported_companies(connection);
1088                             break;
1089                         default:
1090                             avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
1091                             break;
1092                     }
1093                     break;
1094                 }
1095                 case AVRCP_PDU_ID_GET_PLAY_STATUS:
1096                     avrcp_target_emit_respond_vendor_dependent_query(avrcp_target_context.avrcp_callback, connection->avrcp_cid, AVRCP_SUBEVENT_PLAY_STATUS_QUERY);
1097                     break;
1098                 case AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE:
1099                     if ((pos + 1) > size) return;
1100                     connection->target_abort_continue_response = true;
1101                     connection->state = AVCTP_W2_SEND_RESPONSE;
1102                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1103                     break;
1104                 case AVRCP_PDU_ID_REQUEST_CONTINUING_RESPONSE:
1105                     if ((pos + 1) > size) return;
1106                     if (packet[pos] != AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES){
1107                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
1108                         return;
1109                     }
1110                     connection->target_continue_response = true;
1111                     connection->target_now_playing_info_response = true;
1112                     connection->state = AVCTP_W2_SEND_RESPONSE;
1113                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1114                     break;
1115                 case AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES:{
1116                     if ((pos + 9) > size) return;
1117                     uint8_t play_identifier[8];
1118                     memset(play_identifier, 0, 8);
1119                     if (memcmp(&packet[pos], play_identifier, 8) != 0) {
1120                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
1121                         return;
1122                     }
1123                     pos += 8;
1124                     uint8_t attribute_count = packet[pos++];
1125                     connection->next_attr_id = AVRCP_MEDIA_ATTR_NONE;
1126                     if (!attribute_count){
1127                         connection->next_attr_id = AVRCP_MEDIA_ATTR_TITLE;
1128                         connection->target_now_playing_info_attr_bitmap = 0xFE;
1129                     } else {
1130                         int i;
1131                         connection->next_attr_id = AVRCP_MEDIA_ATTR_TITLE;
1132                         connection->target_now_playing_info_attr_bitmap = 0;
1133                         if ((pos + attribute_count * 4) > size) return;
1134                         for (i=0; i < attribute_count; i++){
1135                             uint32_t attr_id = big_endian_read_32(packet, pos);
1136                             connection->target_now_playing_info_attr_bitmap |= (1 << attr_id);
1137                             pos += 4;
1138                         }
1139                     }
1140                     log_info("target_now_playing_info_attr_bitmap 0x%02x", connection->target_now_playing_info_attr_bitmap);
1141                     connection->target_now_playing_info_response = true;
1142                     connection->state = AVCTP_W2_SEND_RESPONSE;
1143                     avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1144                     break;
1145                 }
1146                 case AVRCP_PDU_ID_REGISTER_NOTIFICATION:{
1147                     if ((pos + 1) > size) return;
1148                     avrcp_notification_event_id_t event_id = (avrcp_notification_event_id_t) packet[pos];
1149 
1150                     avrcp_target_set_transaction_label_for_notification(connection, event_id, connection->transaction_id);
1151 
1152                     if (event_id < AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED ||
1153                         event_id > AVRCP_NOTIFICATION_EVENT_MAX_VALUE){
1154                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
1155                         return;
1156                     }
1157 
1158                     switch (event_id){
1159                         case AVRCP_NOTIFICATION_EVENT_AVAILABLE_PLAYERS_CHANGED:
1160                         case AVRCP_NOTIFICATION_EVENT_PLAYER_APPLICATION_SETTING_CHANGED:
1161                         case AVRCP_NOTIFICATION_EVENT_UIDS_CHANGED:
1162                         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_END:
1163                         case AVRCP_NOTIFICATION_EVENT_TRACK_REACHED_START:
1164                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_POS_CHANGED:
1165                         case AVRCP_NOTIFICATION_EVENT_SYSTEM_STATUS_CHANGED:
1166                         case AVRCP_NOTIFICATION_EVENT_MAX_VALUE:
1167                             avrcp_target_response_vendor_dependent_not_implemented(connection, pdu_id, event_id);
1168                             return;
1169                         default:
1170                             break;
1171                     }
1172 
1173                     event_mask = (1 << event_id);
1174                     connection->notifications_enabled |= event_mask;
1175 
1176                     switch (event_id){
1177                         case AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED:
1178                             if (connection->target_track_selected){
1179                                 avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_SELECTED, 8);
1180                             } else {
1181                                 avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, AVRCP_NOTIFICATION_TRACK_NOT_SELECTED, 8);
1182                             }
1183                             break;
1184                         case AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED:
1185                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, (const uint8_t *)&connection->target_playback_status, 1);
1186                             break;
1187                         case AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED:
1188                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, NULL, 0);
1189                             break;
1190                         case AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED:
1191                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, (const uint8_t *)&connection->target_absolute_volume, 1);
1192                             break;
1193                         case AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED:
1194                             avrcp_target_response_vendor_dependent_interim(connection, pdu_id, event_id, (const uint8_t *)&connection->target_battery_status, 1);
1195                             break;
1196                         case AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED:
1197                             avrcp_target_response_addressed_player_changed_interim(connection, pdu_id, event_id);
1198                             return;
1199                         default:
1200                             btstack_assert(false);
1201                             return;
1202                     }
1203                     break;
1204                 }
1205                 case AVRCP_PDU_ID_SET_ABSOLUTE_VOLUME: {
1206                     if ( (length != 1) || ((pos + 1) > size)){
1207                         avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
1208                         break;
1209                     }
1210 
1211                     uint8_t absolute_volume = packet[pos];
1212                     if (absolute_volume < 0x80){
1213                         connection->target_absolute_volume = absolute_volume;
1214                     }
1215                     avrcp_target_emit_volume_changed(avrcp_target_context.avrcp_callback, connection->avrcp_cid, connection->target_absolute_volume);
1216                     avrcp_target_vendor_dependent_response_accept(connection, pdu_id, connection->target_absolute_volume);
1217                     break;
1218                 }
1219                 default:
1220                     log_info("AVRCP target: unhandled pdu id 0x%02x", pdu_id);
1221                     avrcp_target_response_vendor_dependent_reject(connection, pdu_id, AVRCP_STATUS_INVALID_COMMAND);
1222                     break;
1223             }
1224             break;
1225         default:
1226             log_info("AVRCP target: opcode 0x%02x not implemented", avrcp_cmd_opcode(packet,size));
1227             break;
1228     }
1229 }
1230 
1231 static void avrcp_target_notification_init(avrcp_connection_t * connection, avrcp_notification_event_id_t notification_id, uint8_t * value, uint16_t value_len){
1232     btstack_assert(value_len + 1 < AVRCP_MAX_COMMAND_PARAMETER_LENGTH);
1233     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_CHANGED_STABLE, AVRCP_PDU_ID_REGISTER_NOTIFICATION);
1234     connection->transaction_id = avrcp_target_get_transaction_label_for_notification(connection, notification_id);
1235 
1236     connection->data_len = 1 + value_len;
1237     connection->data[0] = notification_id;
1238     if (value != NULL){
1239         (void)memcpy(connection->data + 1, value, value_len);
1240     }
1241 }
1242 
1243 static void avrcp_target_notification_addressed_player_changed_init(avrcp_connection_t * connection){
1244     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_CHANGED_STABLE, AVRCP_PDU_ID_REGISTER_NOTIFICATION);
1245     connection->transaction_id = avrcp_target_get_transaction_label_for_notification(connection, AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED);
1246 
1247     connection->data_len = 5;
1248     connection->data[0] = AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED;
1249     big_endian_store_16(connection->data, 1, connection->target_addressed_player_id);
1250     big_endian_store_16(connection->data, 3, connection->target_uid_counter);
1251 }
1252 
1253 
1254 static void avrcp_target_reset_notification(avrcp_connection_t * connection, avrcp_notification_event_id_t notification_id){
1255     if (notification_id < AVRCP_NOTIFICATION_EVENT_FIRST_INDEX || notification_id > AVRCP_NOTIFICATION_EVENT_LAST_INDEX){
1256         return;
1257     }
1258     connection->notifications_enabled &= ~(1 << notification_id);
1259     connection->target_notifications_transaction_label[notification_id] = 0;
1260 }
1261 
1262 static void avrcp_request_next_avctp_segment(avrcp_connection_t * connection){
1263     // AVCTP
1264     switch (connection->avctp_packet_type){
1265         case AVCTP_END_PACKET:
1266         case AVCTP_SINGLE_PACKET:
1267             connection->state = AVCTP_CONNECTION_OPENED;
1268             break;
1269         default:
1270             connection->state = AVCTP_W2_SEND_RESPONSE;
1271             avrcp_request_can_send_now(connection, connection->l2cap_signaling_cid);
1272             break;
1273     }
1274 }
1275 
1276 static void avrcp_target_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
1277     avrcp_connection_t * connection;
1278     avrcp_notification_event_id_t notification_id = AVRCP_NOTIFICATION_EVENT_NONE;
1279 
1280     switch (packet_type){
1281         case L2CAP_DATA_PACKET:
1282             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, channel);
1283             avrcp_handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
1284             return;
1285 
1286         case HCI_EVENT_PACKET:
1287             if (hci_event_packet_get_type(packet) != L2CAP_EVENT_CAN_SEND_NOW){
1288                 return;
1289             }
1290 
1291             connection = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, channel);
1292             if (connection == NULL){
1293                 return;
1294             }
1295 
1296             if (connection->state == AVCTP_W2_SEND_RESPONSE){
1297                 // start AVCTP
1298                 if (connection->target_reject_transport_header){
1299                     connection->target_reject_transport_header = false;
1300                     avctp_send_reject_cmd_wrong_pid(connection);
1301                     connection->state = AVCTP_CONNECTION_OPENED;
1302                     return;
1303                 }
1304                 // end AVCTP
1305 
1306                 // start AVRCP
1307                 if (connection->target_abort_continue_response){
1308                     connection->target_abort_continue_response = false;
1309                     avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_ACCEPTED, AVRCP_PDU_ID_REQUEST_ABORT_CONTINUING_RESPONSE);
1310                     break;
1311                 }
1312 
1313                 if (connection->target_now_playing_info_response){
1314                     connection->target_now_playing_info_response = false;
1315                     if (connection->target_continue_response){
1316                         connection->target_continue_response = false;
1317                         if (connection->data_len == 0){
1318                             avrcp_target_response_vendor_dependent_reject(connection, connection->pdu_id, AVRCP_STATUS_INVALID_PARAMETER);
1319                             return;
1320                         }
1321                     } else {
1322                         avrcp_target_vendor_dependent_response_data_init(connection, AVRCP_CTYPE_RESPONSE_IMPLEMENTED_STABLE, AVRCP_PDU_ID_GET_ELEMENT_ATTRIBUTES);
1323                         connection->data_len = avrcp_now_playing_info_value_len_with_headers(connection);
1324                     }
1325                     break;
1326                 }
1327 
1328                 // data already prepared
1329                 break;
1330             }
1331 
1332             // Notifications
1333 
1334             if (connection->target_track_changed){
1335                 connection->target_track_changed = false;
1336                 notification_id = AVRCP_NOTIFICATION_EVENT_TRACK_CHANGED;
1337                 avrcp_target_notification_init(connection, notification_id, connection->target_track_id, 8);
1338                 break;
1339             }
1340 
1341             if (connection->target_playback_status_changed){
1342                 connection->target_playback_status_changed = false;
1343                 notification_id = AVRCP_NOTIFICATION_EVENT_PLAYBACK_STATUS_CHANGED;
1344                 uint8_t playback_status = (uint8_t) connection->target_playback_status;
1345                 avrcp_target_notification_init(connection, notification_id, &playback_status, 1);
1346                 break;
1347             }
1348 
1349             if (connection->target_playing_content_changed){
1350                 connection->target_playing_content_changed = false;
1351                 notification_id = AVRCP_NOTIFICATION_EVENT_NOW_PLAYING_CONTENT_CHANGED;
1352                 avrcp_target_notification_init(connection, notification_id, NULL, 0);
1353                 break;
1354             }
1355 
1356             if (connection->target_battery_status_changed){
1357                 connection->target_battery_status_changed = false;
1358                 notification_id = AVRCP_NOTIFICATION_EVENT_BATT_STATUS_CHANGED;
1359                 avrcp_target_notification_init(connection, notification_id, (uint8_t *)&connection->target_battery_status, 1);
1360                 break;
1361             }
1362 
1363             if (connection->target_notify_absolute_volume_changed){
1364                 connection->target_notify_absolute_volume_changed = false;
1365                 notification_id = AVRCP_NOTIFICATION_EVENT_VOLUME_CHANGED;
1366                 avrcp_target_notification_init(connection, notification_id, &connection->target_absolute_volume, 1);
1367                 break;
1368             }
1369 
1370             if (connection->target_addressed_player_changed){
1371                 connection->target_addressed_player_changed = false;
1372                 notification_id = AVRCP_NOTIFICATION_EVENT_ADDRESSED_PLAYER_CHANGED;
1373                 avrcp_target_notification_addressed_player_changed_init(connection);
1374                 break;
1375             }
1376 
1377             // nothing to send, exit
1378             return;
1379 
1380         default:
1381             return;
1382     }
1383 
1384     avrcp_send_response_with_avctp_fragmentation(connection);
1385     avrcp_target_reset_notification(connection, notification_id);
1386     avrcp_request_next_avctp_segment(connection);
1387 }
1388 
1389 void avrcp_target_init(void){
1390     avrcp_target_context.role = AVRCP_TARGET;
1391     avrcp_target_context.packet_handler = avrcp_target_packet_handler;
1392     avrcp_register_target_packet_handler(&avrcp_target_packet_handler);
1393 }
1394 
1395 void avrcp_target_deinit(void){
1396     memset(&avrcp_target_context, 0, sizeof(avrcp_context_t));
1397 }
1398 
1399 void avrcp_target_register_packet_handler(btstack_packet_handler_t callback){
1400     btstack_assert(callback != NULL);
1401     avrcp_target_context.avrcp_callback = callback;
1402 }
1403 
1404 void avrcp_target_register_set_addressed_player_handler(bool (*callback)(uint16_t player_id)){
1405     btstack_assert(callback != NULL);
1406     avrcp_target_context.set_addressed_player_callback = callback;
1407 }
1408 
1409 
1410