xref: /btstack/src/classic/avrcp_browsing_target.c (revision 4c1f1aed2b5e8b1d5869fcba4ebf2029a9e9453e)
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_browsing_target.c"
39 
40 #include <stdint.h>
41 #include <string.h>
42 #include <inttypes.h>
43 #include "classic/avrcp.h"
44 #include "classic/avrcp_browsing.h"
45 #include "classic/avrcp_browsing_target.h"
46 #include "classic/avrcp_target.h"
47 #include "classic/avrcp_controller.h"
48 
49 #include "bluetooth_sdp.h"
50 #include "btstack_debug.h"
51 #include "btstack_event.h"
52 
53 static void avrcp_browsing_target_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
54 
55 static int avrcp_browsing_target_handle_can_send_now(avrcp_browsing_connection_t * connection){
56     int pos = 0;
57 
58     // l2cap_reserve_packet_buffer();
59     // uint8_t * packet = l2cap_get_outgoing_buffer();
60     uint8_t packet[400];
61     connection->packet_type = AVRCP_SINGLE_PACKET;
62 
63     packet[pos++] = (connection->transaction_label << 4) | (connection->packet_type << 2) | (AVRCP_RESPONSE_FRAME << 1) | 0;
64     // Profile IDentifier (PID)
65     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
66     packet[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
67     (void)memcpy(packet + pos, connection->cmd_operands,
68                  connection->cmd_operands_length);
69 
70     pos += connection->cmd_operands_length;
71     connection->wait_to_send = false;
72     // return l2cap_send_prepared(connection->l2cap_browsing_cid, pos);
73     return l2cap_send(connection->l2cap_browsing_cid, packet, pos);
74 }
75 
76 
77 static uint8_t avrcp_browsing_target_response_general_reject(avrcp_browsing_connection_t * connection, avrcp_status_code_t status){
78     // AVRCP_CTYPE_RESPONSE_REJECTED
79     int pos = 0;
80     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GENERAL_REJECT;
81     // connection->message_body[pos++] = 0;
82     // param length
83     big_endian_store_16(connection->cmd_operands, pos, 1);
84     pos += 2;
85     connection->cmd_operands[pos++] = status;
86     connection->cmd_operands_length = 4;
87     connection->state = AVCTP_W2_SEND_RESPONSE;
88     avrcp_browsing_request_can_send_now(connection, connection->l2cap_browsing_cid);
89     return ERROR_CODE_SUCCESS;
90 }
91 
92 static void avrcp_browsing_target_emit_get_folder_items(btstack_packet_handler_t callback, uint16_t browsing_cid, avrcp_browsing_connection_t * connection){
93     btstack_assert(callback != NULL);
94 
95     uint8_t event[18];
96     int pos = 0;
97     event[pos++] = HCI_EVENT_AVRCP_META;
98     event[pos++] = sizeof(event) - 2;
99     event[pos++] = AVRCP_SUBEVENT_BROWSING_GET_FOLDER_ITEMS;
100     little_endian_store_16(event, pos, browsing_cid);
101     pos += 2;
102     event[pos++] = connection->scope;
103     big_endian_store_32(event, pos, connection->start_item);
104     pos += 4;
105     big_endian_store_32(event, pos, connection->end_item);
106     pos += 4;
107     big_endian_store_32(event, pos, connection->attr_bitmap);
108     pos += 4;
109     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
110 }
111 
112 static void avrcp_browsing_target_emit_get_total_num_items(btstack_packet_handler_t callback, uint16_t browsing_cid, avrcp_browsing_connection_t * connection){
113     btstack_assert(callback != NULL);
114 
115     uint8_t event[10];
116     int pos = 0;
117     event[pos++] = HCI_EVENT_AVRCP_META;
118     event[pos++] = sizeof(event) - 2;
119     event[pos++] = AVRCP_SUBEVENT_BROWSING_GET_TOTAL_NUM_ITEMS;
120     little_endian_store_16(event, pos, browsing_cid);
121     pos += 2;
122     event[pos++] = connection->scope;
123     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
124 }
125 
126 static void avrcp_browsing_target_emit_set_browsed_player(btstack_packet_handler_t callback, uint16_t browsing_cid, uint16_t browsed_player_id){
127     btstack_assert(callback != NULL);
128 
129     uint8_t event[10];
130     int pos = 0;
131     event[pos++] = HCI_EVENT_AVRCP_META;
132     event[pos++] = sizeof(event) - 2;
133     event[pos++] = AVRCP_SUBEVENT_BROWSING_SET_BROWSED_PLAYER;
134     little_endian_store_16(event, pos, browsing_cid);
135     pos += 2;
136     little_endian_store_16(event, pos, browsed_player_id);
137     pos += 2;
138     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
139 }
140 
141 static void avrcp_browsing_target_emit_change_path(btstack_packet_handler_t callback, uint16_t browsing_cid, uint16_t uid_counter, avrcp_browsing_direction_t direction, uint8_t * item_id){
142     btstack_assert(callback != NULL);
143 
144     uint8_t event[19];
145     int pos = 0;
146     event[pos++] = HCI_EVENT_AVRCP_META;
147     event[pos++] = sizeof(event) - 2;
148     event[pos++] = AVRCP_SUBEVENT_BROWSING_CHANGE_PATH;
149     little_endian_store_16(event, pos, browsing_cid);
150     pos += 2;
151     little_endian_store_16(event, pos, uid_counter);
152     pos += 2;
153     event[pos++] = direction;
154     memcpy(&event[pos], item_id, 8);
155     pos += 8;
156     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
157 }
158 
159 static void avrcp_browsing_target_emit_get_item_attributes(btstack_packet_handler_t callback, uint16_t browsing_cid, uint16_t uid_counter, uint8_t scope, uint8_t * item_id, uint8_t attr_num, uint8_t * attr_list){
160     btstack_assert(callback != NULL);
161     btstack_assert(attr_num <= AVRCP_MEDIA_ATTR_NUM);
162 
163     uint8_t event[19 + 4 * AVRCP_MEDIA_ATTR_NUM];
164     int pos = 0;
165     event[pos++] = HCI_EVENT_AVRCP_META;
166     event[pos++] = sizeof(event) - 2;
167     event[pos++] = AVRCP_SUBEVENT_BROWSING_GET_ITEM_ATTRIBUTES;
168     little_endian_store_16(event, pos, browsing_cid);
169     pos += 2;
170     little_endian_store_16(event, pos, uid_counter);
171     pos += 2;
172     event[pos++] = scope;
173     memcpy(&event[pos], item_id, 8);
174     pos += 8;
175     uint16_t attr_len = attr_num * 4;
176     little_endian_store_16(event, pos, attr_len);
177     pos += 2;
178 
179     memcpy(&event[pos], attr_list, attr_len);
180     pos += attr_len;
181     (*callback)(HCI_EVENT_PACKET, 0, event, pos);
182 }
183 
184 static void avrcp_browsing_target_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
185     UNUSED(size);
186     avrcp_browsing_connection_t * browsing_connection;
187     avrcp_browsing_direction_t direction;
188 
189     switch (packet_type) {
190         case L2CAP_DATA_PACKET:{
191             browsing_connection = avrcp_get_browsing_connection_for_l2cap_cid_for_role(AVRCP_TARGET, channel);
192             if (!browsing_connection) break;
193             int pos = 0;
194             uint8_t transport_header = packet[pos++];
195             // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
196             browsing_connection->transaction_label = transport_header >> 4;
197             avctp_packet_type_t avctp_packet_type = (avctp_packet_type_t)((transport_header & 0x0F) >> 2);
198             switch (avctp_packet_type){
199                 case AVCTP_SINGLE_PACKET:
200                 case AVCTP_START_PACKET:
201                     browsing_connection->subunit_type = packet[pos++] >> 2;
202                     browsing_connection->subunit_id = 0;
203                     browsing_connection->command_opcode = packet[pos++];
204                     browsing_connection->num_packets = 1;
205                     if (avctp_packet_type == AVCTP_START_PACKET){
206                         browsing_connection->num_packets = packet[pos++];
207                     }
208                     browsing_connection->pdu_id = packet[pos++];
209                     uint16_t parameter_length = big_endian_read_16(packet, pos);
210                     pos += 2;
211 
212                     switch(browsing_connection->pdu_id){
213                         case AVRCP_PDU_ID_GET_FOLDER_ITEMS:
214                             if (parameter_length < 10){
215                                 avrcp_browsing_target_response_general_reject(browsing_connection, AVRCP_STATUS_INVALID_COMMAND);
216                                 break;
217                             }
218 
219                             browsing_connection->scope = packet[pos++];
220                             browsing_connection->start_item = big_endian_read_32(packet, pos);
221                             pos += 4;
222                             browsing_connection->end_item = big_endian_read_32(packet, pos);
223                             pos += 4;
224                             uint8_t attr_count = packet[pos++];
225                             browsing_connection->attr_bitmap = 0;
226 
227                             while (attr_count){
228                                 uint32_t attr_id = big_endian_read_32(packet, pos);
229                                 pos += 4;
230                                 browsing_connection->attr_bitmap |= (1 << attr_id);
231                                 attr_count--;
232                             }
233                             avrcp_browsing_target_emit_get_folder_items(avrcp_target_context.browsing_avrcp_callback, channel, browsing_connection);
234                             break;
235 
236                         case AVRCP_PDU_ID_GET_TOTAL_NUMBER_OF_ITEMS:{
237                             // send total num items
238                             if (parameter_length != 1){
239                                 avrcp_browsing_target_response_general_reject(browsing_connection, AVRCP_STATUS_INVALID_SCOPE);
240                                 break;
241                             }
242 
243                             browsing_connection->scope = packet[pos++];
244                             avrcp_browsing_target_emit_get_total_num_items(avrcp_target_context.browsing_avrcp_callback, channel, browsing_connection);
245                             break;
246                         }
247                         case AVRCP_PDU_ID_SET_BROWSED_PLAYER:
248                             // player_id (2)
249                             if (parameter_length != 2){
250                                 avrcp_browsing_target_response_general_reject(browsing_connection, AVRCP_STATUS_INVALID_COMMAND);
251                                 break;
252                             }
253                             if ( (pos + 2) > size ){
254                                 avrcp_browsing_target_response_general_reject(browsing_connection, AVRCP_STATUS_INVALID_PLAYER_ID);
255                                 break;
256                             }
257                             avrcp_browsing_target_emit_set_browsed_player(avrcp_target_context.browsing_avrcp_callback, channel, big_endian_read_16(packet, pos));
258                             break;
259 
260                         case AVRCP_PDU_ID_CHANGE_PATH:
261                             // one level up or down in the virtual filesystem
262                             if (parameter_length != 11){
263                                 avrcp_browsing_target_response_general_reject(browsing_connection, AVRCP_STATUS_INVALID_COMMAND);
264                                 break;
265                             }
266                             browsing_connection->uid_counter = big_endian_read_16(packet, pos);
267                             pos += 2;
268                             browsing_connection->direction = (avrcp_browsing_direction_t)packet[pos++];
269 
270                             if (browsing_connection->direction > AVRCP_BROWSING_DIRECTION_FOLDER_RFU){
271                                 avrcp_browsing_target_response_general_reject(browsing_connection, AVRCP_STATUS_INVALID_DIRECTION);
272                                 break;
273                             }
274                             memcpy(browsing_connection->item_uid, &packet[pos], 8);
275                             avrcp_browsing_target_emit_change_path(avrcp_target_context.browsing_avrcp_callback, channel, browsing_connection->uid_counter, browsing_connection->direction, browsing_connection->item_uid);
276                             break;
277 
278                         case AVRCP_PDU_ID_GET_ITEM_ATTRIBUTES:{
279                             if (parameter_length < 12){
280                                 avrcp_browsing_target_response_general_reject(browsing_connection, AVRCP_STATUS_INVALID_COMMAND);
281                                 break;
282                             }
283 
284                             browsing_connection->scope = packet[pos++];
285                             memcpy(browsing_connection->item_uid, &packet[pos], 8);
286                             pos += 8;
287                             browsing_connection->uid_counter = big_endian_read_16(packet, pos);
288                             pos += 2;
289                             browsing_connection->attr_list_size = packet[pos++];
290                             browsing_connection->attr_list = &packet[pos];
291 
292                             avrcp_browsing_target_emit_get_item_attributes(avrcp_target_context.browsing_avrcp_callback, channel, browsing_connection->uid_counter,
293                                                                            browsing_connection->scope, browsing_connection->item_uid, browsing_connection->attr_list_size, browsing_connection->attr_list);
294                             break;
295                         }
296 
297                         default:
298                             avrcp_browsing_target_response_general_reject(browsing_connection, AVRCP_STATUS_INVALID_COMMAND);
299                             log_info("not parsed pdu ID 0x%02x", browsing_connection->pdu_id);
300                             break;
301                     }
302                     browsing_connection->state = AVCTP_CONNECTION_OPENED;
303                     break;
304 
305                 default:
306                     break;
307             }
308             break;
309         }
310 
311         case HCI_EVENT_PACKET:
312             switch (hci_event_packet_get_type(packet)){
313                 case L2CAP_EVENT_CAN_SEND_NOW:
314                     browsing_connection = avrcp_get_browsing_connection_for_l2cap_cid_for_role(AVRCP_TARGET, channel);
315                     if (browsing_connection->state != AVCTP_W2_SEND_RESPONSE) return;
316                     browsing_connection->state = AVCTP_CONNECTION_OPENED;
317                     avrcp_browsing_target_handle_can_send_now(browsing_connection);
318                     break;
319                 default:
320                     break;
321             }
322             break;
323 
324         default:
325             break;
326     }
327 }
328 
329 void avrcp_browsing_target_init(void){
330     avrcp_target_context.browsing_packet_handler = avrcp_browsing_target_packet_handler;
331     avrcp_browsing_register_target_packet_handler(avrcp_browsing_target_packet_handler);
332 }
333 
334 void avrcp_browsing_target_deinit(void){
335     avrcp_controller_context.browsing_packet_handler = NULL;
336 }
337 
338 void avrcp_browsing_target_register_packet_handler(btstack_packet_handler_t callback){
339     btstack_assert(callback != NULL);
340     avrcp_target_context.browsing_avrcp_callback = callback;
341 }
342 
343 uint8_t avrcp_browsing_target_send_get_folder_items_response(uint16_t avrcp_browsing_cid, uint16_t uid_counter, uint8_t * attr_list, uint16_t attr_list_size, uint16_t num_items){
344     avrcp_connection_t * avrcp_connection = avrcp_get_connection_for_browsing_cid_for_role(AVRCP_TARGET, avrcp_browsing_cid);
345     if (!avrcp_connection){
346         log_error("Could not find an AVRCP Target connection for browsing_cid 0x%02x.", avrcp_browsing_cid);
347         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
348     }
349 
350     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
351     if (!connection){
352         log_info("Could not find a browsing connection.");
353         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
354     }
355     if (connection->state != AVCTP_CONNECTION_OPENED){
356         return ERROR_CODE_COMMAND_DISALLOWED;
357     }
358 
359     // TODO: handle response to SetAddressedPlayer
360 
361     uint16_t pos = 0;
362     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_FOLDER_ITEMS;
363     uint8_t param_length = 5;
364     uint8_t param_length_pos = pos;
365     pos += 2;
366 
367     avrcp_status_code_t status = AVRCP_STATUS_SUCCESS;
368     uint8_t status_pos = pos;
369     pos++;
370 
371     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
372     pos += 2;
373 
374     // TODO: fragmentation
375     if (attr_list_size >  sizeof(connection->cmd_operands)){
376         connection->attr_list = attr_list;
377         connection->attr_list_size = attr_list_size;
378         log_info(" todo: list too big, invoke fragmentation");
379         return 1;
380     }
381 
382     uint16_t items_byte_len = 0;
383     if (connection->start_item < num_items) {
384         if (connection->end_item < num_items) {
385             items_byte_len =  connection->end_item - connection->start_item + 1;
386         } else {
387             items_byte_len = num_items - connection->start_item;
388         }
389 
390     } else {
391         big_endian_store_16(connection->cmd_operands, pos, 0);
392         pos += 2;
393     }
394     big_endian_store_16(connection->cmd_operands, pos, items_byte_len);
395     pos += 2;
396     param_length += items_byte_len;
397 
398     if (items_byte_len > 0){
399         (void)memcpy(&connection->cmd_operands[pos], attr_list, attr_list_size);
400         pos += attr_list_size;
401         connection->cmd_operands_length = pos;
402     } else {
403         status = AVRCP_STATUS_RANGE_OUT_OF_BOUNDS;
404         param_length = 1;
405         connection->cmd_operands_length = status_pos + 1;
406     }
407 
408     big_endian_store_16(connection->cmd_operands, param_length_pos, param_length);
409     connection->cmd_operands[status_pos] = status;
410 
411     btstack_assert(pos <= 400);
412 
413 
414     connection->state = AVCTP_W2_SEND_RESPONSE;
415     avrcp_browsing_request_can_send_now(connection, connection->l2cap_browsing_cid);
416     return ERROR_CODE_SUCCESS;
417 }
418 
419 uint8_t avrcp_browsing_target_send_change_path_response(uint16_t avrcp_browsing_cid, uint16_t uid_counter, avrcp_status_code_t status, uint32_t num_items){
420     avrcp_connection_t * avrcp_connection = avrcp_get_connection_for_browsing_cid_for_role(AVRCP_TARGET, avrcp_browsing_cid);
421     if (!avrcp_connection){
422         log_error("Could not find an AVRCP Target connection for browsing_cid 0x%02x.", avrcp_browsing_cid);
423         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
424     }
425 
426     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
427     if (!connection){
428         log_info("Could not find a browsing connection.");
429         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
430     }
431     if (connection->state != AVCTP_CONNECTION_OPENED){
432         return ERROR_CODE_COMMAND_DISALLOWED;
433     }
434 
435     uint16_t pos = 0;
436     connection->cmd_operands[pos++] = AVRCP_PDU_ID_CHANGE_PATH;
437     // Param length
438     big_endian_store_16(connection->cmd_operands, pos, 5);
439     pos += 2;
440     connection->cmd_operands[pos++] = status;
441     big_endian_store_32(connection->cmd_operands, pos, num_items);
442     pos += 4;
443 
444     connection->cmd_operands_length = pos;
445     connection->state = AVCTP_W2_SEND_RESPONSE;
446     avrcp_browsing_request_can_send_now(connection, connection->l2cap_browsing_cid);
447     return ERROR_CODE_SUCCESS;
448 }
449 
450 uint8_t avrcp_browsing_target_send_get_item_attributes_response(uint16_t avrcp_browsing_cid, avrcp_status_code_t status, uint8_t * attr_list, uint16_t attr_list_size, uint8_t num_items){
451     avrcp_connection_t * avrcp_connection = avrcp_get_connection_for_browsing_cid_for_role(AVRCP_TARGET, avrcp_browsing_cid);
452     if (!avrcp_connection){
453         log_error("Could not find an AVRCP Target connection for browsing_cid 0x%02x.", avrcp_browsing_cid);
454         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
455     }
456 
457     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
458     if (!connection){
459         log_info("Could not find a browsing connection.");
460         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
461     }
462     if (connection->state != AVCTP_CONNECTION_OPENED){
463         return ERROR_CODE_COMMAND_DISALLOWED;
464     }
465 
466     // TODO: fragmentation
467     if (attr_list_size >  (sizeof(connection->cmd_operands) - 5)){
468         connection->attr_list = attr_list;
469         connection->attr_list_size = attr_list_size;
470         log_info(" todo: list too big, invoke fragmentation");
471         return 1;
472     }
473 
474     uint16_t pos = 0;
475     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_ITEM_ATTRIBUTES;
476 
477     uint8_t param_length_pos = pos;
478     big_endian_store_16(connection->cmd_operands, pos, 1);
479     pos += 2;
480     connection->cmd_operands[pos++] = status;
481 
482     if (status != AVRCP_STATUS_SUCCESS){
483         connection->cmd_operands_length = pos;
484         connection->state = AVCTP_W2_SEND_RESPONSE;
485         avrcp_browsing_request_can_send_now(connection, connection->l2cap_browsing_cid);
486         return ERROR_CODE_SUCCESS;
487     }
488 
489     connection->cmd_operands[pos++] = num_items;
490     (void)memcpy(&connection->cmd_operands[pos], attr_list, attr_list_size);
491     pos += attr_list_size;
492 
493     big_endian_store_16(connection->cmd_operands, param_length_pos, pos - 3);
494     connection->cmd_operands_length = pos;
495     connection->state = AVCTP_W2_SEND_RESPONSE;
496     avrcp_browsing_request_can_send_now(connection, connection->l2cap_browsing_cid);
497     return ERROR_CODE_SUCCESS;
498 }
499 
500 uint8_t avrcp_browsing_target_send_accept_set_browsed_player(uint16_t avrcp_browsing_cid, uint16_t uid_counter, uint16_t browsed_player_id, uint8_t * response, uint16_t response_size){
501     avrcp_connection_t * avrcp_connection = avrcp_get_connection_for_browsing_cid_for_role(AVRCP_TARGET, avrcp_browsing_cid);
502     if (!avrcp_connection){
503         log_error("Could not find an AVRCP Target connection for browsing_cid 0x%02x.", avrcp_browsing_cid);
504         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
505     }
506 
507     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
508     if (!connection){
509         log_info("Could not find a browsing connection.");
510         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
511     }
512 
513     if (connection->state != AVCTP_CONNECTION_OPENED) {
514         log_info("Browsing connection wrong state.");
515         return ERROR_CODE_COMMAND_DISALLOWED;
516     }
517 
518     connection->browsed_player_id = browsed_player_id;
519 
520     uint16_t pos = 0;
521     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_BROWSED_PLAYER;
522     big_endian_store_16(connection->cmd_operands, pos, response_size + 2 + 1); // uuid counter + status
523     pos += 2;
524 
525     connection->cmd_operands[pos++] = AVRCP_STATUS_SUCCESS;
526     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
527     pos += 2;
528 
529     // TODO: fragmentation
530     if (response_size >  sizeof(connection->cmd_operands)){
531         connection->attr_list = response;
532         connection->attr_list_size = response_size;
533         log_info(" todo: list too big, invoke fragmentation");
534         return 1;
535     }
536 
537     (void)memcpy(&connection->cmd_operands[pos], response, response_size);
538     pos += response_size;
539 	btstack_assert(pos <= 255);
540     connection->cmd_operands_length = (uint8_t) pos;
541 
542     connection->state = AVCTP_W2_SEND_RESPONSE;
543     avrcp_browsing_request_can_send_now(connection, connection->l2cap_browsing_cid);
544     return ERROR_CODE_SUCCESS;
545 }
546 
547 uint8_t avrcp_browsing_target_send_reject_set_browsed_player(uint16_t avrcp_browsing_cid, avrcp_status_code_t status){
548     avrcp_connection_t * avrcp_connection = avrcp_get_connection_for_browsing_cid_for_role(AVRCP_TARGET, avrcp_browsing_cid);
549     if (!avrcp_connection){
550         log_error("Could not find an AVRCP Target connection for browsing_cid 0x%02x.", avrcp_browsing_cid);
551         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
552     }
553 
554     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
555     if (!connection){
556         log_info("Could not find a browsing connection.");
557         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
558     }
559 
560     if (connection->state != AVCTP_CONNECTION_OPENED) {
561         log_info("Browsing connection wrong state.");
562         return ERROR_CODE_COMMAND_DISALLOWED;
563     }
564 
565     int pos = 0;
566     connection->cmd_operands[pos++] = AVRCP_PDU_ID_SET_BROWSED_PLAYER;
567     big_endian_store_16(connection->cmd_operands, pos, 1);
568     pos += 2;
569     connection->cmd_operands[pos++] = status;
570     connection->cmd_operands_length = pos;
571 
572     connection->state = AVCTP_W2_SEND_RESPONSE;
573     avrcp_browsing_request_can_send_now(connection, connection->l2cap_browsing_cid);
574     return ERROR_CODE_SUCCESS;
575 }
576 
577 uint8_t avrcp_browsing_target_send_get_total_num_items_response(uint16_t avrcp_browsing_cid, uint16_t uid_counter, uint32_t total_num_items){
578     avrcp_connection_t * avrcp_connection = avrcp_get_connection_for_browsing_cid_for_role(AVRCP_TARGET, avrcp_browsing_cid);
579     if (!avrcp_connection){
580         log_error("Could not find an AVRCP Target connection for browsing_cid 0x%02x.", avrcp_browsing_cid);
581         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
582     }
583 
584     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
585     if (!connection){
586         log_info("Could not find a browsing connection.");
587         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
588     }
589 
590     if (connection->state != AVCTP_CONNECTION_OPENED) {
591         log_info("Browsing connection wrong state.");
592         return ERROR_CODE_COMMAND_DISALLOWED;
593     }
594 
595     int pos = 0;
596     connection->cmd_operands[pos++] = AVRCP_PDU_ID_GET_TOTAL_NUMBER_OF_ITEMS;
597     big_endian_store_16(connection->cmd_operands, pos, 7);
598     pos += 2;
599     connection->cmd_operands[pos++] = AVRCP_STATUS_SUCCESS;
600     big_endian_store_16(connection->cmd_operands, pos, uid_counter);
601     pos += 2;
602     big_endian_store_32(connection->cmd_operands, pos, total_num_items);
603     pos += 4;
604     connection->cmd_operands_length = pos;
605 
606     connection->state = AVCTP_W2_SEND_RESPONSE;
607     avrcp_browsing_request_can_send_now(connection, connection->l2cap_browsing_cid);
608     return ERROR_CODE_SUCCESS;
609 }
610 
611