xref: /btstack/src/classic/avrcp_browsing_controller.c (revision 97faea967f4d0587a0f8eea2c60f9b7b81f08cf2)
1 /*
2  * Copyright (C) 2016 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define __BTSTACK_FILE__ "avrcp_browsing_controller.c"
39 
40 #include <stdint.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <inttypes.h>
45 #include "btstack.h"
46 #include "classic/avrcp.h"
47 #include "classic/avrcp_browsing_controller.h"
48 
49 #define PSM_AVCTP_BROWSING              0x001b
50 
51 static void avrcp_browser_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avrcp_context_t * context);
52 static void avrcp_browsing_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
53 
54 static avrcp_connection_t * get_avrcp_connection_for_browsing_cid(uint16_t browsing_cid, avrcp_context_t * context){
55     btstack_linked_list_iterator_t it;
56     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
57     while (btstack_linked_list_iterator_has_next(&it)){
58         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
59         if (connection->avrcp_browsing_cid != browsing_cid) continue;
60         return connection;
61     }
62     return NULL;
63 }
64 
65 static avrcp_connection_t * get_avrcp_connection_for_browsing_l2cap_cid(uint16_t browsing_l2cap_cid, avrcp_context_t * context){
66     btstack_linked_list_iterator_t it;
67     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
68     while (btstack_linked_list_iterator_has_next(&it)){
69         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
70         if (connection->browsing_connection &&  connection->browsing_connection->l2cap_browsing_cid != browsing_l2cap_cid) continue;
71         return connection;
72     }
73     return NULL;
74 }
75 
76 static avrcp_browsing_connection_t * get_avrcp_browsing_connection_for_l2cap_cid(uint16_t l2cap_cid, avrcp_context_t * context){
77     btstack_linked_list_iterator_t it;
78     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
79     while (btstack_linked_list_iterator_has_next(&it)){
80         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
81         if (connection->browsing_connection && connection->browsing_connection->l2cap_browsing_cid != l2cap_cid) continue;
82         return connection->browsing_connection;
83     }
84     return NULL;
85 }
86 
87 static void avrcp_emit_browsing_connection_established(btstack_packet_handler_t callback, uint16_t browsing_cid, bd_addr_t addr, uint8_t status){
88     if (!callback) return;
89     uint8_t event[12];
90     int pos = 0;
91     event[pos++] = HCI_EVENT_AVRCP_META;
92     event[pos++] = sizeof(event) - 2;
93     event[pos++] = AVRCP_SUBEVENT_BROWSING_CONNECTION_ESTABLISHED;
94     event[pos++] = status;
95     reverse_bd_addr(addr,&event[pos]);
96     pos += 6;
97     little_endian_store_16(event, pos, browsing_cid);
98     pos += 2;
99     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
100 }
101 
102 static void avrcp_emit_incoming_browsing_connection(btstack_packet_handler_t callback, uint16_t browsing_cid, bd_addr_t addr){
103     if (!callback) return;
104     uint8_t event[11];
105     int pos = 0;
106     event[pos++] = HCI_EVENT_AVRCP_META;
107     event[pos++] = sizeof(event) - 2;
108     event[pos++] = AVRCP_SUBEVENT_INCOMING_BROWSING_CONNECTION;
109     reverse_bd_addr(addr,&event[pos]);
110     pos += 6;
111     little_endian_store_16(event, pos, browsing_cid);
112     pos += 2;
113     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
114 }
115 
116 static void avrcp_emit_browsing_connection_closed(btstack_packet_handler_t callback, uint16_t browsing_cid){
117     if (!callback) return;
118     uint8_t event[5];
119     int pos = 0;
120     event[pos++] = HCI_EVENT_AVRCP_META;
121     event[pos++] = sizeof(event) - 2;
122     event[pos++] = AVRCP_SUBEVENT_BROWSING_CONNECTION_RELEASED;
123     little_endian_store_16(event, pos, browsing_cid);
124     pos += 2;
125     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
126 }
127 
128 static avrcp_browsing_connection_t * avrcp_browsing_create_connection(avrcp_connection_t * avrcp_connection){
129     avrcp_browsing_connection_t * connection = btstack_memory_avrcp_browsing_connection_get();
130     memset(connection, 0, sizeof(avrcp_browsing_connection_t));
131     connection->state = AVCTP_CONNECTION_IDLE;
132     connection->transaction_label = 0xFF;
133     avrcp_connection->avrcp_browsing_cid = avrcp_get_next_cid();
134     avrcp_connection->browsing_connection = connection;
135     return connection;
136 }
137 
138 static uint8_t avrcp_browsing_connect(bd_addr_t remote_addr, avrcp_context_t * context, uint8_t * ertm_buffer, uint32_t size, l2cap_ertm_config_t * ertm_config, uint16_t * browsing_cid){
139     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_bd_addr(remote_addr, context);
140 
141     if (!avrcp_connection){
142         log_error("avrcp: there is no previously established AVRCP controller connection.");
143         return ERROR_CODE_COMMAND_DISALLOWED;
144     }
145 
146     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
147     if (connection){
148         log_error(" avrcp_browsing_connect connection exists.");
149         return ERROR_CODE_SUCCESS;
150     }
151 
152     connection = avrcp_browsing_create_connection(avrcp_connection);
153     if (!connection){
154         log_error("avrcp: could not allocate connection struct.");
155         return BTSTACK_MEMORY_ALLOC_FAILED;
156     }
157 
158     if (browsing_cid){
159         *browsing_cid = avrcp_connection->avrcp_browsing_cid;
160     }
161 
162     connection->ertm_buffer = ertm_buffer;
163     connection->ertm_buffer_size = size;
164     avrcp_connection->browsing_connection = connection;
165     avrcp_connection->browsing_connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
166     memcpy(&connection->ertm_config, ertm_config, sizeof(l2cap_ertm_config_t));
167 
168     return l2cap_create_ertm_channel(avrcp_browsing_controller_packet_handler, remote_addr, avrcp_connection->browsing_l2cap_psm,
169                     &connection->ertm_config, connection->ertm_buffer, connection->ertm_buffer_size, NULL);
170 
171 }
172 
173 static void avrcp_browser_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avrcp_context_t * context){
174     UNUSED(channel);
175     UNUSED(size);
176     bd_addr_t event_addr;
177     uint16_t local_cid;
178     uint8_t  status;
179     avrcp_browsing_connection_t * browsing_connection = NULL;
180     avrcp_connection_t * avrcp_connection = NULL;
181 
182     if (packet_type != HCI_EVENT_PACKET) return;
183 
184     switch (hci_event_packet_get_type(packet)) {
185         case HCI_EVENT_DISCONNECTION_COMPLETE:
186             avrcp_emit_browsing_connection_closed(context->browsing_avrcp_callback, 0);
187             break;
188         case L2CAP_EVENT_INCOMING_CONNECTION:
189             l2cap_event_incoming_connection_get_address(packet, event_addr);
190             local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
191             avrcp_connection = get_avrcp_connection_for_bd_addr(event_addr, context);
192             if (!avrcp_connection) {
193                 log_error("No previously created AVRCP controller connections");
194                 l2cap_decline_connection(local_cid);
195                 break;
196             }
197             browsing_connection = avrcp_browsing_create_connection(avrcp_connection);
198             browsing_connection->l2cap_browsing_cid = local_cid;
199             browsing_connection->state = AVCTP_CONNECTION_W4_ERTM_CONFIGURATION;
200             log_info("Emit AVRCP_SUBEVENT_INCOMING_BROWSING_CONNECTION browsing_cid 0x%02x, l2cap_signaling_cid 0x%02x\n", avrcp_connection->avrcp_browsing_cid, browsing_connection->l2cap_browsing_cid);
201             avrcp_emit_incoming_browsing_connection(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid, event_addr);
202             break;
203 
204         case L2CAP_EVENT_CHANNEL_OPENED:
205             l2cap_event_channel_opened_get_address(packet, event_addr);
206             status = l2cap_event_channel_opened_get_status(packet);
207             local_cid = l2cap_event_channel_opened_get_local_cid(packet);
208 
209             avrcp_connection = get_avrcp_connection_for_bd_addr(event_addr, context);
210             if (!avrcp_connection){
211                 log_error("Failed to find AVRCP connection for bd_addr %s", bd_addr_to_str(event_addr));
212                 avrcp_emit_browsing_connection_established(context->browsing_avrcp_callback, local_cid, event_addr, L2CAP_LOCAL_CID_DOES_NOT_EXIST);
213                 l2cap_disconnect(local_cid, 0); // reason isn't used
214                 break;
215             }
216 
217             browsing_connection = avrcp_connection->browsing_connection;
218             if (status != ERROR_CODE_SUCCESS){
219                 log_info("L2CAP connection to connection %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
220                 avrcp_emit_browsing_connection_established(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid, event_addr, status);
221                 btstack_memory_avrcp_browsing_connection_free(browsing_connection);
222                 avrcp_connection->browsing_connection = NULL;
223                 break;
224             }
225             browsing_connection->l2cap_browsing_cid = local_cid;
226 
227             log_info("L2CAP_EVENT_CHANNEL_OPENED browsing cid 0x%02x, l2cap cid 0x%02x", avrcp_connection->avrcp_browsing_cid, browsing_connection->l2cap_browsing_cid);
228             browsing_connection->state = AVCTP_CONNECTION_OPENED;
229             avrcp_emit_browsing_connection_established(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid, event_addr, ERROR_CODE_SUCCESS);
230             break;
231 
232         case L2CAP_EVENT_CHANNEL_CLOSED:
233             // data: event (8), len(8), channel (16)
234             local_cid = l2cap_event_channel_closed_get_local_cid(packet);
235             avrcp_connection = get_avrcp_connection_for_browsing_l2cap_cid(local_cid, context);
236 
237             if (avrcp_connection && avrcp_connection->browsing_connection){
238                 avrcp_emit_browsing_connection_closed(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid);
239                 // free connection
240                 btstack_memory_avrcp_browsing_connection_free(avrcp_connection->browsing_connection);
241                 avrcp_connection->browsing_connection = NULL;
242                 break;
243             }
244             break;
245         default:
246             break;
247     }
248 }
249 
250 static int avrcp_browsing_controller_send_get_folder_items_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
251     uint8_t command[100];
252     int pos = 0;
253 
254     // // if (connection->cmd_operands[3] == AVRCP_PDU_ID_GET_CAPABILITIES){
255     //     printf("cheet\n");
256     //     uint8_t buffer[] = {0xB0, 0x11, 0x0E, 0xFF, 0x00, 0x02, 0xFF, 0xFF};
257     //     memcpy(command, buffer, sizeof(buffer));
258     //     pos =  sizeof(buffer);
259     //     return l2cap_send(cid, command, pos);
260     // // }
261 
262     // transport header
263     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
264     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
265     // Profile IDentifier (PID)
266     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
267     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
268     command[pos++] = AVRCP_PDU_ID_GET_FOLDER_ITEMS;
269 
270     uint32_t attribute_count = 0;
271     uint32_t attributes_to_copy = 0;
272 
273     switch (connection->attr_bitmap){
274         case AVRCP_MEDIA_ATTR_NONE:
275             attribute_count = AVRCP_MEDIA_ATTR_NONE; // 0xFFFFFFFF
276             break;
277         case AVRCP_MEDIA_ATTR_ALL:
278             attribute_count = AVRCP_MEDIA_ATTR_ALL;  // 0
279             break;
280         default:
281             attribute_count = count_set_bits_uint32(connection->attr_bitmap & 0xff);
282             attributes_to_copy = attribute_count;
283             break;
284     }
285 
286     big_endian_store_16(command, pos, 9 + attribute_count*4);
287     pos += 2;
288     command[pos++] = connection->scope;
289     big_endian_store_32(command, pos, connection->start_item);
290     pos += 4;
291     big_endian_store_32(command, pos, connection->end_item);
292     pos += 4;
293     command[pos++] = attribute_count;
294 
295     int bit_position = 1;
296     while (attributes_to_copy){
297         if (connection->attr_bitmap & (1 << bit_position)){
298             big_endian_store_32(command, pos, bit_position);
299             pos += 4;
300             attributes_to_copy--;
301         }
302         bit_position++;
303     }
304 
305 
306     return l2cap_send(cid, command, pos);
307 }
308 
309 
310 static int avrcp_browsing_controller_send_get_item_attributes_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
311     uint8_t command[100];
312     int pos = 0;
313     // transport header
314     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
315     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
316     // Profile IDentifier (PID)
317     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
318     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
319     command[pos++] = AVRCP_PDU_ID_GET_ITEM_ATTRIBUTES;
320 
321     uint32_t attribute_count = 0;
322     uint32_t attributes_to_copy = 0;
323 
324     switch (connection->attr_bitmap){
325         case AVRCP_MEDIA_ATTR_NONE:
326             attribute_count = AVRCP_MEDIA_ATTR_NONE; // 0xFFFFFFFF
327             break;
328         case AVRCP_MEDIA_ATTR_ALL:
329             attribute_count = AVRCP_MEDIA_ATTR_ALL;  // 0
330             break;
331         default:
332             attribute_count = count_set_bits_uint32(connection->attr_bitmap & 0xff);
333             attributes_to_copy = attribute_count;
334             break;
335     }
336 
337     big_endian_store_16(command, pos, 12 + attribute_count*4);
338     pos += 2;
339 
340     command[pos++] = connection->scope;
341     memcpy(command+pos, connection->folder_uid, 8);
342     pos += 8;
343     big_endian_store_16(command, pos, connection->uid_counter);
344     pos += 2;
345     command[pos++] = attribute_count;
346 
347     int bit_position = 1;
348     while (attributes_to_copy){
349         if (connection->attr_bitmap & (1 << bit_position)){
350             big_endian_store_32(command, pos, bit_position);
351             pos += 4;
352             attributes_to_copy--;
353         }
354         bit_position++;
355     }
356 
357     return l2cap_send(cid, command, pos);
358 }
359 
360 
361 static int avrcp_browsing_controller_send_change_path_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
362     uint8_t command[100];
363     int pos = 0;
364     // transport header
365     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
366     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
367     // Profile IDentifier (PID)
368     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
369     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
370     command[pos++] = AVRCP_PDU_ID_CHANGE_PATH;
371 
372     big_endian_store_16(command, pos, 11);
373     pos += 2;
374     pos += 2;
375     command[pos++] = connection->direction;
376     memcpy(command+pos, connection->folder_uid, 8);
377     pos += 8;
378     return l2cap_send(cid, command, pos);
379 }
380 
381 static int avrcp_browsing_controller_send_search_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
382     uint8_t command[100];
383     int pos = 0;
384     // transport header
385     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
386     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
387     // Profile IDentifier (PID)
388     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
389     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
390     command[pos++] = AVRCP_PDU_ID_SEARCH;
391 
392     big_endian_store_16(command, pos, 4 + connection->search_str_len);
393     pos += 2;
394 
395     big_endian_store_16(command, pos, 0x006A);
396     pos += 2;
397     big_endian_store_16(command, pos, connection->search_str_len);
398     pos += 2;
399 
400     memcpy(command+pos,connection->search_str, connection->search_str_len);
401     pos += connection->search_str_len;
402     return l2cap_send(cid, command, pos);
403 }
404 
405 static int avrcp_browsing_controller_send_set_browsed_player_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
406     uint8_t command[100];
407     int pos = 0;
408     // transport header
409     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
410     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
411     // Profile IDentifier (PID)
412     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
413     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
414     command[pos++] = AVRCP_PDU_ID_SET_BROWSED_PLAYER;
415 
416     big_endian_store_16(command, pos, 2);
417     pos += 2;
418     big_endian_store_16(command, pos, connection->browsed_player_id);
419     pos += 2;
420     return l2cap_send(cid, command, pos);
421 }
422 
423 static int avrcp_browsing_controller_send_get_total_nr_items_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
424     uint8_t command[7];
425     int pos = 0;
426     // transport header
427     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
428     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
429     // Profile IDentifier (PID)
430     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
431     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
432     command[pos++] = AVRCP_PDU_ID_GET_TOTAL_NUMBER_OF_ITEMS;
433 
434     big_endian_store_16(command, pos, 1);
435     pos += 2;
436     command[pos++] = connection->get_total_nr_items_scope;
437     return l2cap_send(cid, command, pos);
438 }
439 
440 static void avrcp_browsing_controller_handle_can_send_now(avrcp_browsing_connection_t * connection){
441     switch (connection->state){
442         case AVCTP_CONNECTION_OPENED:
443             if (connection->set_browsed_player_id){
444                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
445                 connection->set_browsed_player_id = 0;
446                 avrcp_browsing_controller_send_set_browsed_player_cmd(connection->l2cap_browsing_cid, connection);
447                 break;
448             }
449 
450             if (connection->get_total_nr_items){
451                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
452                 connection->get_total_nr_items = 0;
453                 avrcp_browsing_controller_send_get_total_nr_items_cmd(connection->l2cap_browsing_cid, connection);
454                 break;
455             }
456 
457             if (connection->get_folder_items){
458                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
459                 connection->get_folder_items = 0;
460                 avrcp_browsing_controller_send_get_folder_items_cmd(connection->l2cap_browsing_cid, connection);
461                 break;
462             }
463 
464             if (connection->get_item_attributes){
465                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
466                 connection->get_item_attributes = 0;
467                 avrcp_browsing_controller_send_get_item_attributes_cmd(connection->l2cap_browsing_cid, connection);
468                 break;
469             }
470 
471             if (connection->change_path){
472                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
473                 connection->change_path = 0;
474                 avrcp_browsing_controller_send_change_path_cmd(connection->l2cap_browsing_cid, connection);
475                 break;
476             }
477 
478             if (connection->search){
479                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
480                 connection->search = 0;
481                 avrcp_browsing_controller_send_search_cmd(connection->l2cap_browsing_cid, connection);
482                 break;
483             }
484             break;
485         default:
486             return;
487     }
488 }
489 
490 
491 static void avrcp_browsing_controller_emit_done_with_uid_counter(btstack_packet_handler_t callback, uint16_t browsing_cid, uint16_t uid_counter, uint8_t browsing_status, uint8_t bluetooth_status){
492     if (!callback) return;
493     uint8_t event[9];
494     int pos = 0;
495     event[pos++] = HCI_EVENT_AVRCP_META;
496     event[pos++] = sizeof(event) - 2;
497     event[pos++] = AVRCP_SUBEVENT_BROWSING_DONE;
498     little_endian_store_16(event, pos, browsing_cid);
499     pos += 2;
500     little_endian_store_16(event, pos, uid_counter);
501     pos += 2;
502     event[pos++] = browsing_status;
503     event[pos++] = bluetooth_status;
504     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
505 }
506 
507 static void avrcp_parser_reset(avrcp_browsing_connection_t * connection){
508     connection->parser_attribute_header_pos = 0;
509     connection->parsed_attribute_value_offset = 0;
510     connection->parsed_num_attributes = 0;
511     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
512 }
513 
514 
515 static void avrcp_browsing_parser_process_byte(uint8_t byte, avrcp_browsing_connection_t * connection){
516     uint8_t prepended_header_size = 1;
517     switch(connection->parser_state){
518         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:{
519             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
520             if (connection->parser_attribute_header_pos < AVRCP_BROWSING_ITEM_HEADER_LEN) break;
521 
522             uint16_t attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 1);
523             connection->parsed_attribute_value[connection->parsed_attribute_value_offset++] = connection->parser_attribute_header[0];   // prepend with item type
524             connection->parsed_attribute_value_len = btstack_min(attribute_total_value_len, AVRCP_MAX_ATTRIBUTTE_SIZE - prepended_header_size);                 // reduce AVRCP_MAX_ATTRIBUTTE_SIZE for the size ot item type
525             connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
526             // printf("AVRCP_PARSER_GET_ATTRIBUTE_HEADER value len %d, to parse %d, offset %d\n", attribute_total_value_len, connection->parsed_attribute_value_len, connection->parsed_attribute_value_offset);
527             break;
528         }
529         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:{
530             connection->parsed_attribute_value[connection->parsed_attribute_value_offset++] = byte;
531             if (connection->parsed_attribute_value_offset < connection->parsed_attribute_value_len + prepended_header_size){
532                 break;
533             }
534             if (connection->parsed_attribute_value_offset < big_endian_read_16(connection->parser_attribute_header, 1)){
535                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
536                 break;
537             }
538             connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
539             (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, connection->l2cap_browsing_cid, &connection->parsed_attribute_value[0], connection->parsed_attribute_value_offset);
540             connection->parsed_num_attributes++;
541             connection->parsed_attribute_value_offset = 0;
542             connection->parser_attribute_header_pos = 0;
543 
544             if (connection->parsed_num_attributes == connection->num_items){
545                 avrcp_parser_reset(connection);
546                 break;
547             }
548             break;
549         }
550         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
551             connection->parsed_attribute_value_offset++;
552             if (connection->parsed_attribute_value_offset < big_endian_read_16(connection->parser_attribute_header, 1) + prepended_header_size){
553                 break;
554             }
555             connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
556             (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, connection->l2cap_browsing_cid, &connection->parsed_attribute_value[0], connection->parsed_attribute_value_offset);
557             connection->parsed_num_attributes++;
558             connection->parsed_attribute_value_offset = 0;
559             connection->parser_attribute_header_pos = 0;
560 
561             if (connection->parsed_num_attributes == connection->num_items){
562                 avrcp_parser_reset(connection);
563                 break;
564             }
565             break;
566         default:
567             break;
568     }
569 }
570 
571 static void avrcp_browsing_parse_and_emit_element_attrs(uint8_t * packet, uint16_t num_bytes_to_read, avrcp_browsing_connection_t * connection){
572     int i;
573     for (i=0;i<num_bytes_to_read;i++){
574         avrcp_browsing_parser_process_byte(packet[i], connection);
575     }
576 }
577 
578 static void avrcp_browsing_controller_emit_failed(btstack_packet_handler_t callback, uint16_t browsing_cid, uint8_t browsing_status, uint8_t bluetooth_status){
579     avrcp_browsing_controller_emit_done_with_uid_counter(callback, browsing_cid, 0, browsing_status, bluetooth_status);
580 }
581 
582 
583 static void avrcp_browsing_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
584     avrcp_browsing_connection_t * browsing_connection;
585 
586     switch (packet_type) {
587         case L2CAP_DATA_PACKET:{
588             browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
589             if (!browsing_connection) break;
590             // printf("received \n");
591             // printf_hexdump(packet,size);
592             int pos = 0;
593             uint8_t transport_header = packet[pos++];
594             // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
595             browsing_connection->transaction_label = transport_header >> 4;
596             avrcp_packet_type_t avctp_packet_type = (transport_header & 0x0F) >> 2;
597             // printf("L2CAP_DATA_PACKET, packet type %d\n", avctp_packet_type);
598             switch (avctp_packet_type){
599                 case AVRCP_SINGLE_PACKET:
600                 case AVRCP_START_PACKET:
601                     // uint8_t frame_type = (transport_header & 0x03) >> 1;
602                     // uint8_t ipid = transport_header & 0x01;
603                     pos += 2;
604                     browsing_connection->num_packets = 1;
605                     if (avctp_packet_type == AVRCP_START_PACKET){
606                         browsing_connection->num_packets = packet[pos++];
607                     }
608                     if (pos + 4 > size){
609                         browsing_connection->state = AVCTP_CONNECTION_OPENED;
610                         avrcp_browsing_controller_emit_failed(avrcp_controller_context.browsing_avrcp_callback, channel, AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND, ERROR_CODE_SUCCESS);
611                         return;
612                     }
613                     browsing_connection->pdu_id = packet[pos++];
614                     // uint16_t length = big_endian_read_16(packet, pos);
615                     pos += 2;
616                     browsing_connection->browsing_status = packet[pos++];
617                     if (browsing_connection->browsing_status != AVRCP_BROWSING_ERROR_CODE_SUCCESS){
618                         browsing_connection->state = AVCTP_CONNECTION_OPENED;
619                         avrcp_browsing_controller_emit_failed(avrcp_controller_context.browsing_avrcp_callback, channel, browsing_connection->browsing_status, ERROR_CODE_SUCCESS);
620                         return;
621                     }
622                     break;
623                 default:
624                     break;
625             }
626 
627             uint32_t i;
628             switch(browsing_connection->pdu_id){
629                 case AVRCP_PDU_ID_CHANGE_PATH:
630                     // printf("AVRCP_PDU_ID_CHANGE_PATH \n");
631                     break;
632                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:
633                     // printf("AVRCP_PDU_ID_SET_ADDRESSED_PLAYER \n");
634                     break;
635                 case AVRCP_PDU_ID_GET_TOTAL_NUMBER_OF_ITEMS:{
636                     // uint32_t num_items = big_endian_read_32(packet, pos);
637                     // pos += 4;
638                     // printf("TODO: send event, uid_counter %d, num_items %d\n", browsing_connection->uid_counter, num_items);
639                     break;
640                 }
641                 case AVRCP_PDU_ID_SET_BROWSED_PLAYER:{
642                     // printf("AVRCP_PDU_ID_SET_BROWSED_PLAYER \n");
643                     browsing_connection->uid_counter =  big_endian_read_16(packet, pos);
644                     pos += 2;
645                     // uint32_t num_items = big_endian_read_32(packet, pos);
646                     pos += 4;
647                     // uint16_t charset = big_endian_read_16(packet, pos);
648                     pos += 2;
649                     uint8_t folder_depth = packet[pos++];
650 
651                     for (i = 0; i < folder_depth; i++){
652                         uint16_t folder_name_length = big_endian_read_16(packet, pos);
653                         pos += 2;
654                         // reuse packet and add data type as a header
655                         packet[pos-1] = AVRCP_BROWSING_MEDIA_ROOT_FOLDER;
656                         (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, packet+pos-1, folder_name_length+1);
657                         pos += folder_name_length;
658                     }
659                     break;
660                 }
661                 case AVRCP_PDU_ID_GET_FOLDER_ITEMS:{
662                     // printf("AVRCP_PDU_ID_GET_FOLDER_ITEMS \n");
663                     switch (avctp_packet_type){
664                         case AVRCP_SINGLE_PACKET:
665                         case AVRCP_START_PACKET:
666                             avrcp_parser_reset(browsing_connection);
667                             browsing_connection->uid_counter =  big_endian_read_16(packet, pos);
668                             pos += 2;
669                             browsing_connection->num_items = big_endian_read_16(packet, pos); //num_items
670                             pos += 2;
671                             avrcp_browsing_parse_and_emit_element_attrs(packet+pos, size-pos, browsing_connection);
672                             break;
673 
674                         case AVRCP_CONTINUE_PACKET:
675                             avrcp_browsing_parse_and_emit_element_attrs(packet+pos, size-pos, browsing_connection);
676                             break;
677 
678                         case AVRCP_END_PACKET:
679                             avrcp_browsing_parse_and_emit_element_attrs(packet+pos, size-pos, browsing_connection);
680                             avrcp_parser_reset(browsing_connection);
681                             break;
682                     }
683                     break;
684                 }
685                 case AVRCP_PDU_ID_SEARCH:{
686                     browsing_connection->uid_counter =  big_endian_read_16(packet, pos);
687                     pos += 2;
688                     // uint32_t num_items = big_endian_read_32(packet, pos);
689                     // printf("TODO: send as event, search found %d items\n", num_items);
690                     break;
691                 }
692                 case AVRCP_PDU_ID_GET_ITEM_ATTRIBUTES:
693                     packet[pos-1] = AVRCP_BROWSING_MEDIA_ELEMENT_ITEM_ATTRIBUTE;
694                     (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, packet+pos-1, size - pos + 1);
695                     break;
696                 default:
697                     log_info(" not parsed pdu ID 0x%02x", browsing_connection->pdu_id);
698                     break;
699             }
700 
701             switch (avctp_packet_type){
702                 case AVRCP_SINGLE_PACKET:
703                 case AVRCP_END_PACKET:
704                     // printf("reset browsing connection state to OPENED\n");
705                     browsing_connection->state = AVCTP_CONNECTION_OPENED;
706                     avrcp_browsing_controller_emit_done_with_uid_counter(avrcp_controller_context.browsing_avrcp_callback, channel, browsing_connection->uid_counter, browsing_connection->browsing_status, ERROR_CODE_SUCCESS);
707                     break;
708                 default:
709                     break;
710             }
711             // printf(" paket done\n");
712             break;
713         }
714         case HCI_EVENT_PACKET:
715             switch (hci_event_packet_get_type(packet)){
716                 case L2CAP_EVENT_CAN_SEND_NOW:
717                     browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
718                     if (!browsing_connection) break;
719                     avrcp_browsing_controller_handle_can_send_now(browsing_connection);
720                     break;
721                 default:
722                     avrcp_browser_packet_handler(packet_type, channel, packet, size, &avrcp_controller_context);
723                     break;
724             }
725             break;
726 
727         default:
728             break;
729     }
730 }
731 
732 void avrcp_browsing_controller_init(void){
733     avrcp_controller_context.browsing_packet_handler = avrcp_browsing_controller_packet_handler;
734     l2cap_register_service(&avrcp_browsing_controller_packet_handler, PSM_AVCTP_BROWSING, 0xffff, LEVEL_2);
735 }
736 
737 void avrcp_browsing_controller_register_packet_handler(btstack_packet_handler_t callback){
738     if (callback == NULL){
739         log_error("avrcp_browsing_controller_register_packet_handler called with NULL callback");
740         return;
741     }
742     avrcp_controller_context.browsing_avrcp_callback = callback;
743 }
744 
745 uint8_t avrcp_browsing_controller_connect(bd_addr_t bd_addr, uint8_t * ertm_buffer, uint32_t size, l2cap_ertm_config_t * ertm_config, uint16_t * avrcp_browsing_cid){
746     return avrcp_browsing_connect(bd_addr, &avrcp_controller_context, ertm_buffer, size, ertm_config, avrcp_browsing_cid);
747 }
748 
749 uint8_t avrcp_browsing_controller_disconnect(uint16_t avrcp_browsing_cid){
750     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
751     if (!avrcp_connection){
752         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
753         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
754     }
755     if (avrcp_connection->browsing_connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
756 
757     l2cap_disconnect(avrcp_connection->browsing_connection->l2cap_browsing_cid, 0);
758     return ERROR_CODE_SUCCESS;
759 }
760 
761 uint8_t avrcp_browsing_controller_configure_incoming_connection(uint16_t avrcp_browsing_cid, uint8_t * ertm_buffer, uint32_t size, l2cap_ertm_config_t * ertm_config){
762     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
763     if (!avrcp_connection){
764         log_error("avrcp_browsing_controller_decline_incoming_connection: could not find a connection.");
765         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
766     }
767     if (!avrcp_connection->browsing_connection){
768         log_error("avrcp_browsing_controller_decline_incoming_connection: no browsing connection.");
769         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
770     }
771 
772     if (avrcp_connection->browsing_connection->state != AVCTP_CONNECTION_W4_ERTM_CONFIGURATION){
773         log_error("avrcp_browsing_controller_decline_incoming_connection: browsing connection in a wrong state.");
774         return ERROR_CODE_COMMAND_DISALLOWED;
775     }
776 
777     avrcp_connection->browsing_connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
778     avrcp_connection->browsing_connection->ertm_buffer = ertm_buffer;
779     avrcp_connection->browsing_connection->ertm_buffer_size = size;
780     memcpy(&avrcp_connection->browsing_connection->ertm_config, ertm_config, sizeof(l2cap_ertm_config_t));
781     l2cap_accept_ertm_connection(avrcp_connection->browsing_connection->l2cap_browsing_cid, &avrcp_connection->browsing_connection->ertm_config, avrcp_connection->browsing_connection->ertm_buffer, avrcp_connection->browsing_connection->ertm_buffer_size);
782     return ERROR_CODE_SUCCESS;
783 }
784 
785 uint8_t avrcp_browsing_controller_decline_incoming_connection(uint16_t avrcp_browsing_cid){
786     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
787     if (!avrcp_connection){
788         log_error("avrcp_browsing_controller_decline_incoming_connection: could not find a connection.");
789         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
790     }
791     if (!avrcp_connection->browsing_connection) return ERROR_CODE_SUCCESS;
792     if (avrcp_connection->browsing_connection->state > AVCTP_CONNECTION_W4_ERTM_CONFIGURATION) return ERROR_CODE_COMMAND_DISALLOWED;
793 
794     l2cap_decline_connection(avrcp_connection->browsing_connection->l2cap_browsing_cid);
795     // free connection
796     btstack_memory_avrcp_browsing_connection_free(avrcp_connection->browsing_connection);
797     avrcp_connection->browsing_connection = NULL;
798     return ERROR_CODE_SUCCESS;
799 }
800 
801 uint8_t avrcp_browsing_controller_get_item_attributes_for_scope(uint16_t avrcp_browsing_cid, uint8_t * uid, uint16_t uid_counter, uint32_t attr_bitmap, avrcp_browsing_scope_t scope){
802     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
803     if (!avrcp_connection){
804         log_error("avrcp_browsing_controller_get_item_attributes: could not find a connection.");
805         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
806     }
807     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
808     if (connection->state != AVCTP_CONNECTION_OPENED){
809         log_error("avrcp_browsing_controller_get_item_attributes: connection in wrong state %d, expected %d.", connection->state, AVCTP_CONNECTION_OPENED);
810         return ERROR_CODE_COMMAND_DISALLOWED;
811     }
812 
813     connection->get_item_attributes = 1;
814     connection->scope = scope;
815     memcpy(connection->folder_uid, uid, 8);
816     connection->uid_counter = uid_counter;
817     connection->attr_bitmap = attr_bitmap;
818 
819     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
820     return ERROR_CODE_SUCCESS;
821 }
822 
823 /**
824  * @brief Retrieve a listing of the contents of a folder.
825  * @param scope    0-player list, 1-virtual file system, 2-search, 3-now playing
826  * @param start_item
827  * @param end_item
828  * @param attribute_count
829  * @param attribute_list
830  **/
831 static uint8_t avrcp_browsing_controller_get_folder_items(uint16_t avrcp_browsing_cid, avrcp_browsing_scope_t scope, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
832     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
833     if (!avrcp_connection){
834         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
835         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
836     }
837     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
838     if (connection->state != AVCTP_CONNECTION_OPENED) {
839         log_error("avrcp_browsing_controller_get_folder_items: connection in wrong state %d, expected %d.", connection->state, AVCTP_CONNECTION_OPENED);
840         return ERROR_CODE_COMMAND_DISALLOWED;
841     }
842 
843     connection->get_folder_items = 1;
844     connection->scope = scope;
845     connection->start_item = start_item;
846     connection->end_item = end_item;
847     connection->attr_bitmap = attr_bitmap;
848 
849     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
850     return ERROR_CODE_SUCCESS;
851 }
852 
853 uint8_t avrcp_browsing_controller_get_media_players(uint16_t avrcp_browsing_cid, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
854     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_MEDIA_PLAYER_LIST, start_item, end_item, attr_bitmap);
855 }
856 
857 uint8_t avrcp_browsing_controller_browse_file_system(uint16_t avrcp_browsing_cid, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
858     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 1, 0, 0xFFFFFFFF, attr_bitmap);
859     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_MEDIA_PLAYER_VIRTUAL_FILESYSTEM, start_item, end_item, attr_bitmap);
860 }
861 
862 uint8_t avrcp_browsing_controller_browse_media(uint16_t avrcp_browsing_cid, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
863     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 2, 0, 0xFFFFFFFF, 0, NULL);
864     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_SEARCH, start_item, end_item, attr_bitmap);
865 }
866 
867 uint8_t avrcp_browsing_controller_browse_now_playing_list(uint16_t avrcp_browsing_cid, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
868     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_NOW_PLAYING, start_item, end_item, attr_bitmap);
869 }
870 
871 
872 uint8_t avrcp_browsing_controller_set_browsed_player(uint16_t avrcp_browsing_cid, uint16_t browsed_player_id){
873     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
874     if (!avrcp_connection){
875         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
876         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
877     }
878 
879     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
880     if (connection->state != AVCTP_CONNECTION_OPENED){
881         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
882         return ERROR_CODE_COMMAND_DISALLOWED;
883     }
884 
885     connection->set_browsed_player_id = 1;
886     connection->browsed_player_id = browsed_player_id;
887     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
888     return ERROR_CODE_SUCCESS;
889 }
890 
891 /**
892  * @brief Retrieve a listing of the contents of a folder.
893  * @param direction     0-folder up, 1-folder down
894  * @param folder_uid    8 bytes long
895  **/
896 uint8_t avrcp_browsing_controller_change_path(uint16_t avrcp_browsing_cid, uint8_t direction, uint8_t * folder_uid){
897     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
898     if (!avrcp_connection){
899         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
900         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
901     }
902 
903     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
904 
905     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
906         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
907         return ERROR_CODE_COMMAND_DISALLOWED;
908     }
909 
910     if (!connection->browsed_player_id){
911         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
912         return ERROR_CODE_COMMAND_DISALLOWED;
913     }
914     connection->change_path = 1;
915     connection->direction = direction;
916     memset(connection->folder_uid, 0, 8);
917     if (folder_uid){
918         memcpy(connection->folder_uid, folder_uid, 8);
919     }
920 
921     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
922     return ERROR_CODE_SUCCESS;
923 }
924 
925 uint8_t avrcp_browsing_controller_go_up_one_level(uint16_t avrcp_browsing_cid){
926     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 0, NULL);
927 }
928 
929 uint8_t avrcp_browsing_controller_go_down_one_level(uint16_t avrcp_browsing_cid, uint8_t * folder_uid){
930     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 1, folder_uid);
931 }
932 
933 uint8_t avrcp_browsing_controller_search(uint16_t avrcp_browsing_cid, uint16_t search_str_len, char * search_str){
934     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
935     if (!avrcp_connection){
936         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
937         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
938     }
939 
940     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
941 
942     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
943         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
944         return ERROR_CODE_COMMAND_DISALLOWED;
945     }
946 
947     if (!connection->browsed_player_id){
948         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
949         return ERROR_CODE_COMMAND_DISALLOWED;
950     }
951     if (!search_str || search_str_len == 0){
952         return AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND;
953     }
954 
955     connection->search = 1;
956 
957     connection->search_str_len = btstack_min(search_str_len, sizeof(connection->search_str)-1);
958     memset(connection->search_str, 0, sizeof(connection->search_str));
959     memcpy(connection->search_str, search_str, connection->search_str_len);
960     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
961     return ERROR_CODE_SUCCESS;
962 }
963 
964 uint8_t avrcp_browsing_controller_get_total_nr_items_for_scope(uint16_t avrcp_browsing_cid, avrcp_browsing_scope_t scope){
965     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
966     if (!avrcp_connection){
967         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
968         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
969     }
970 
971     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
972 
973     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
974         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
975         return ERROR_CODE_COMMAND_DISALLOWED;
976     }
977 
978     if (!connection->browsed_player_id){
979         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
980         return ERROR_CODE_COMMAND_DISALLOWED;
981     }
982     connection->get_total_nr_items = 1;
983     connection->get_total_nr_items_scope = scope;
984     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
985     return ERROR_CODE_SUCCESS;
986 }
987