xref: /btstack/src/classic/avrcp_browsing_controller.c (revision 398a95ec8e0d408db97ed8e80c67c74e30698a03)
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 
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             if (browsing_connection->state != AVCTP_CONNECTION_W4_L2CAP_CONNECTED) break;
226 
227             browsing_connection->l2cap_browsing_cid = local_cid;
228 
229             log_info("L2CAP_EVENT_CHANNEL_OPENED browsing cid 0x%02x, l2cap cid 0x%02x", avrcp_connection->avrcp_browsing_cid, browsing_connection->l2cap_browsing_cid);
230             browsing_connection->state = AVCTP_CONNECTION_OPENED;
231             avrcp_emit_browsing_connection_established(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid, event_addr, ERROR_CODE_SUCCESS);
232             break;
233 
234         case L2CAP_EVENT_CHANNEL_CLOSED:
235             // data: event (8), len(8), channel (16)
236             local_cid = l2cap_event_channel_closed_get_local_cid(packet);
237             avrcp_connection = get_avrcp_connection_for_browsing_l2cap_cid(local_cid, context);
238 
239             if (avrcp_connection && avrcp_connection->browsing_connection){
240                 avrcp_emit_browsing_connection_closed(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid);
241                 // free connection
242                 btstack_memory_avrcp_browsing_connection_free(avrcp_connection->browsing_connection);
243                 avrcp_connection->browsing_connection = NULL;
244                 break;
245             }
246             break;
247         default:
248             break;
249     }
250 }
251 
252 static int avrcp_browsing_controller_send_get_folder_items_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
253     uint8_t command[100];
254     int pos = 0;
255 
256     // // if (connection->cmd_operands[3] == AVRCP_PDU_ID_GET_CAPABILITIES){
257     //     printf("cheet\n");
258     //     uint8_t buffer[] = {0xB0, 0x11, 0x0E, 0xFF, 0x00, 0x02, 0xFF, 0xFF};
259     //     memcpy(command, buffer, sizeof(buffer));
260     //     pos =  sizeof(buffer);
261     //     return l2cap_send(cid, command, pos);
262     // // }
263 
264     // transport header
265     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
266     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
267     // Profile IDentifier (PID)
268     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
269     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
270     command[pos++] = AVRCP_PDU_ID_GET_FOLDER_ITEMS;
271 
272     uint32_t attribute_count = 0;
273     uint32_t attributes_to_copy = 0;
274 
275     switch (connection->attr_bitmap){
276         case AVRCP_MEDIA_ATTR_NONE:
277             attribute_count = AVRCP_MEDIA_ATTR_NONE; // 0xFFFFFFFF
278             break;
279         case AVRCP_MEDIA_ATTR_ALL:
280             attribute_count = AVRCP_MEDIA_ATTR_ALL;  // 0
281             break;
282         default:
283             attribute_count = count_set_bits_uint32(connection->attr_bitmap & 0xff);
284             attributes_to_copy = attribute_count;
285             break;
286     }
287 
288     big_endian_store_16(command, pos, 9 + attribute_count*4);
289     pos += 2;
290     command[pos++] = connection->scope;
291     big_endian_store_32(command, pos, connection->start_item);
292     pos += 4;
293     big_endian_store_32(command, pos, connection->end_item);
294     pos += 4;
295     command[pos++] = attribute_count;
296 
297     int bit_position = 1;
298     while (attributes_to_copy){
299         if (connection->attr_bitmap & (1 << bit_position)){
300             big_endian_store_32(command, pos, bit_position);
301             pos += 4;
302             attributes_to_copy--;
303         }
304         bit_position++;
305     }
306 
307 
308     return l2cap_send(cid, command, pos);
309 }
310 
311 
312 static int avrcp_browsing_controller_send_get_item_attributes_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
313     uint8_t command[100];
314     int pos = 0;
315     // transport header
316     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
317     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
318     // Profile IDentifier (PID)
319     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
320     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
321     command[pos++] = AVRCP_PDU_ID_GET_ITEM_ATTRIBUTES;
322 
323     uint32_t attribute_count = 0;
324     uint32_t attributes_to_copy = 0;
325 
326     switch (connection->attr_bitmap){
327         case AVRCP_MEDIA_ATTR_NONE:
328             attribute_count = AVRCP_MEDIA_ATTR_NONE; // 0xFFFFFFFF
329             break;
330         case AVRCP_MEDIA_ATTR_ALL:
331             attribute_count = AVRCP_MEDIA_ATTR_ALL;  // 0
332             break;
333         default:
334             attribute_count = count_set_bits_uint32(connection->attr_bitmap & 0xff);
335             attributes_to_copy = attribute_count;
336             break;
337     }
338 
339     big_endian_store_16(command, pos, 12 + attribute_count*4);
340     pos += 2;
341 
342     command[pos++] = connection->scope;
343     memcpy(command+pos, connection->folder_uid, 8);
344     pos += 8;
345     big_endian_store_16(command, pos, connection->uid_counter);
346     pos += 2;
347     command[pos++] = attribute_count;
348 
349     int bit_position = 1;
350     while (attributes_to_copy){
351         if (connection->attr_bitmap & (1 << bit_position)){
352             big_endian_store_32(command, pos, bit_position);
353             pos += 4;
354             attributes_to_copy--;
355         }
356         bit_position++;
357     }
358 
359     return l2cap_send(cid, command, pos);
360 }
361 
362 
363 static int avrcp_browsing_controller_send_change_path_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
364     uint8_t command[100];
365     int pos = 0;
366     // transport header
367     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
368     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
369     // Profile IDentifier (PID)
370     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
371     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
372     command[pos++] = AVRCP_PDU_ID_CHANGE_PATH;
373 
374     big_endian_store_16(command, pos, 11);
375     pos += 2;
376     pos += 2;
377     command[pos++] = connection->direction;
378     memcpy(command+pos, connection->folder_uid, 8);
379     pos += 8;
380     return l2cap_send(cid, command, pos);
381 }
382 
383 static int avrcp_browsing_controller_send_search_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
384     uint8_t command[100];
385     int pos = 0;
386     // transport header
387     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
388     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
389     // Profile IDentifier (PID)
390     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
391     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
392     command[pos++] = AVRCP_PDU_ID_SEARCH;
393 
394     big_endian_store_16(command, pos, 4 + connection->search_str_len);
395     pos += 2;
396 
397     big_endian_store_16(command, pos, 0x006A);
398     pos += 2;
399     big_endian_store_16(command, pos, connection->search_str_len);
400     pos += 2;
401 
402     memcpy(command+pos,connection->search_str, connection->search_str_len);
403     pos += connection->search_str_len;
404     return l2cap_send(cid, command, pos);
405 }
406 
407 static int avrcp_browsing_controller_send_set_browsed_player_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
408     uint8_t command[100];
409     int pos = 0;
410     // transport header
411     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
412     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
413     // Profile IDentifier (PID)
414     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
415     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
416     command[pos++] = AVRCP_PDU_ID_SET_BROWSED_PLAYER;
417 
418     big_endian_store_16(command, pos, 2);
419     pos += 2;
420     big_endian_store_16(command, pos, connection->browsed_player_id);
421     pos += 2;
422     return l2cap_send(cid, command, pos);
423 }
424 
425 static int avrcp_browsing_controller_send_get_total_nr_items_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
426     uint8_t command[7];
427     int pos = 0;
428     // transport header
429     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
430     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
431     // Profile IDentifier (PID)
432     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
433     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
434     command[pos++] = AVRCP_PDU_ID_GET_TOTAL_NUMBER_OF_ITEMS;
435 
436     big_endian_store_16(command, pos, 1);
437     pos += 2;
438     command[pos++] = connection->get_total_nr_items_scope;
439     return l2cap_send(cid, command, pos);
440 }
441 
442 static void avrcp_browsing_controller_handle_can_send_now(avrcp_browsing_connection_t * connection){
443     switch (connection->state){
444         case AVCTP_CONNECTION_OPENED:
445             if (connection->set_browsed_player_id){
446                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
447                 connection->set_browsed_player_id = 0;
448                 avrcp_browsing_controller_send_set_browsed_player_cmd(connection->l2cap_browsing_cid, connection);
449                 break;
450             }
451 
452             if (connection->get_total_nr_items){
453                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
454                 connection->get_total_nr_items = 0;
455                 avrcp_browsing_controller_send_get_total_nr_items_cmd(connection->l2cap_browsing_cid, connection);
456                 break;
457             }
458 
459             if (connection->get_folder_items){
460                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
461                 connection->get_folder_items = 0;
462                 avrcp_browsing_controller_send_get_folder_items_cmd(connection->l2cap_browsing_cid, connection);
463                 break;
464             }
465 
466             if (connection->get_item_attributes){
467                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
468                 connection->get_item_attributes = 0;
469                 avrcp_browsing_controller_send_get_item_attributes_cmd(connection->l2cap_browsing_cid, connection);
470                 break;
471             }
472 
473             if (connection->change_path){
474                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
475                 connection->change_path = 0;
476                 avrcp_browsing_controller_send_change_path_cmd(connection->l2cap_browsing_cid, connection);
477                 break;
478             }
479 
480             if (connection->search){
481                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
482                 connection->search = 0;
483                 avrcp_browsing_controller_send_search_cmd(connection->l2cap_browsing_cid, connection);
484                 break;
485             }
486             break;
487         default:
488             return;
489     }
490 }
491 
492 
493 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){
494     if (!callback) return;
495     uint8_t event[9];
496     int pos = 0;
497     event[pos++] = HCI_EVENT_AVRCP_META;
498     event[pos++] = sizeof(event) - 2;
499     event[pos++] = AVRCP_SUBEVENT_BROWSING_DONE;
500     little_endian_store_16(event, pos, browsing_cid);
501     pos += 2;
502     little_endian_store_16(event, pos, uid_counter);
503     pos += 2;
504     event[pos++] = browsing_status;
505     event[pos++] = bluetooth_status;
506     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
507 }
508 
509 static void avrcp_parser_reset(avrcp_browsing_connection_t * connection){
510     connection->parser_attribute_header_pos = 0;
511     connection->parsed_attribute_value_offset = 0;
512     connection->parsed_num_attributes = 0;
513     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
514 }
515 
516 
517 static void avrcp_browsing_parser_process_byte(uint8_t byte, avrcp_browsing_connection_t * connection){
518     uint8_t prepended_header_size = 1;
519     switch(connection->parser_state){
520         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:{
521             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
522             if (connection->parser_attribute_header_pos < AVRCP_BROWSING_ITEM_HEADER_LEN) break;
523 
524             uint16_t attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 1);
525             connection->parsed_attribute_value[connection->parsed_attribute_value_offset++] = connection->parser_attribute_header[0];   // prepend with item type
526             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
527             connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
528             // 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);
529             break;
530         }
531         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:{
532             connection->parsed_attribute_value[connection->parsed_attribute_value_offset++] = byte;
533             if (connection->parsed_attribute_value_offset < connection->parsed_attribute_value_len + prepended_header_size){
534                 break;
535             }
536             if (connection->parsed_attribute_value_offset < big_endian_read_16(connection->parser_attribute_header, 1)){
537                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
538                 break;
539             }
540             connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
541             (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, connection->l2cap_browsing_cid, &connection->parsed_attribute_value[0], connection->parsed_attribute_value_offset);
542             connection->parsed_num_attributes++;
543             connection->parsed_attribute_value_offset = 0;
544             connection->parser_attribute_header_pos = 0;
545 
546             if (connection->parsed_num_attributes == connection->num_items){
547                 avrcp_parser_reset(connection);
548                 break;
549             }
550             break;
551         }
552         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
553             connection->parsed_attribute_value_offset++;
554             if (connection->parsed_attribute_value_offset < big_endian_read_16(connection->parser_attribute_header, 1) + prepended_header_size){
555                 break;
556             }
557             connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
558             (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, connection->l2cap_browsing_cid, &connection->parsed_attribute_value[0], connection->parsed_attribute_value_offset);
559             connection->parsed_num_attributes++;
560             connection->parsed_attribute_value_offset = 0;
561             connection->parser_attribute_header_pos = 0;
562 
563             if (connection->parsed_num_attributes == connection->num_items){
564                 avrcp_parser_reset(connection);
565                 break;
566             }
567             break;
568         default:
569             break;
570     }
571 }
572 
573 static void avrcp_browsing_parse_and_emit_element_attrs(uint8_t * packet, uint16_t num_bytes_to_read, avrcp_browsing_connection_t * connection){
574     int i;
575     for (i=0;i<num_bytes_to_read;i++){
576         avrcp_browsing_parser_process_byte(packet[i], connection);
577     }
578 }
579 
580 static void avrcp_browsing_controller_emit_failed(btstack_packet_handler_t callback, uint16_t browsing_cid, uint8_t browsing_status, uint8_t bluetooth_status){
581     avrcp_browsing_controller_emit_done_with_uid_counter(callback, browsing_cid, 0, browsing_status, bluetooth_status);
582 }
583 
584 
585 static void avrcp_browsing_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
586     avrcp_browsing_connection_t * browsing_connection;
587 
588     switch (packet_type) {
589         case L2CAP_DATA_PACKET:{
590             browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
591             if (!browsing_connection) break;
592             // printf("received \n");
593             // printf_hexdump(packet,size);
594             int pos = 0;
595             uint8_t transport_header = packet[pos++];
596             // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
597             browsing_connection->transaction_label = transport_header >> 4;
598             avrcp_packet_type_t avctp_packet_type = (transport_header & 0x0F) >> 2;
599             // printf("L2CAP_DATA_PACKET, packet type %d\n", avctp_packet_type);
600             switch (avctp_packet_type){
601                 case AVRCP_SINGLE_PACKET:
602                 case AVRCP_START_PACKET:
603                     // uint8_t frame_type = (transport_header & 0x03) >> 1;
604                     // uint8_t ipid = transport_header & 0x01;
605                     pos += 2;
606                     browsing_connection->num_packets = 1;
607                     if (avctp_packet_type == AVRCP_START_PACKET){
608                         browsing_connection->num_packets = packet[pos++];
609                     }
610                     if (pos + 4 > size){
611                         browsing_connection->state = AVCTP_CONNECTION_OPENED;
612                         avrcp_browsing_controller_emit_failed(avrcp_controller_context.browsing_avrcp_callback, channel, AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND, ERROR_CODE_SUCCESS);
613                         return;
614                     }
615                     browsing_connection->pdu_id = packet[pos++];
616                     // uint16_t length = big_endian_read_16(packet, pos);
617                     pos += 2;
618                     browsing_connection->browsing_status = packet[pos++];
619                     if (browsing_connection->browsing_status != AVRCP_BROWSING_ERROR_CODE_SUCCESS){
620                         browsing_connection->state = AVCTP_CONNECTION_OPENED;
621                         avrcp_browsing_controller_emit_failed(avrcp_controller_context.browsing_avrcp_callback, channel, browsing_connection->browsing_status, ERROR_CODE_SUCCESS);
622                         return;
623                     }
624                     break;
625                 default:
626                     break;
627             }
628 
629             uint32_t i;
630             switch(browsing_connection->pdu_id){
631                 case AVRCP_PDU_ID_CHANGE_PATH:
632                     // printf("AVRCP_PDU_ID_CHANGE_PATH \n");
633                     break;
634                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:
635                     // printf("AVRCP_PDU_ID_SET_ADDRESSED_PLAYER \n");
636                     break;
637                 case AVRCP_PDU_ID_GET_TOTAL_NUMBER_OF_ITEMS:{
638                     // uint32_t num_items = big_endian_read_32(packet, pos);
639                     // pos += 4;
640                     // printf("TODO: send event, uid_counter %d, num_items %d\n", browsing_connection->uid_counter, num_items);
641                     break;
642                 }
643                 case AVRCP_PDU_ID_SET_BROWSED_PLAYER:{
644                     browsing_connection->uid_counter =  big_endian_read_16(packet, pos);
645                     pos += 2;
646                     // uint32_t num_items = big_endian_read_32(packet, pos);
647                     pos += 4;
648                     // uint16_t charset = big_endian_read_16(packet, pos);
649                     pos += 2;
650                     uint8_t folder_depth = packet[pos++];
651 
652                     for (i = 0; i < folder_depth; i++){
653                         uint16_t folder_name_length = big_endian_read_16(packet, pos);
654                         pos += 2;
655                         // reuse packet and add data type as a header
656                         packet[pos-1] = AVRCP_BROWSING_MEDIA_ROOT_FOLDER;
657                         (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, packet+pos-1, folder_name_length+1);
658                         pos += folder_name_length;
659                     }
660                     break;
661                 }
662 
663                 case AVRCP_PDU_ID_GET_FOLDER_ITEMS:{
664                     switch (avctp_packet_type){
665                         case AVRCP_SINGLE_PACKET:
666                         case AVRCP_START_PACKET:
667                             avrcp_parser_reset(browsing_connection);
668                             browsing_connection->uid_counter =  big_endian_read_16(packet, pos);
669                             pos += 2;
670                             browsing_connection->num_items = big_endian_read_16(packet, pos); //num_items
671                             pos += 2;
672                             avrcp_browsing_parse_and_emit_element_attrs(packet+pos, size-pos, browsing_connection);
673                             break;
674 
675                         case AVRCP_CONTINUE_PACKET:
676                             avrcp_browsing_parse_and_emit_element_attrs(packet+pos, size-pos, browsing_connection);
677                             break;
678 
679                         case AVRCP_END_PACKET:
680                             avrcp_browsing_parse_and_emit_element_attrs(packet+pos, size-pos, browsing_connection);
681                             avrcp_parser_reset(browsing_connection);
682                             break;
683                     }
684                     break;
685                 }
686 
687                 case AVRCP_PDU_ID_SEARCH:{
688                     browsing_connection->uid_counter =  big_endian_read_16(packet, pos);
689                     pos += 2;
690                     // uint32_t num_items = big_endian_read_32(packet, pos);
691                     // printf("TODO: send as event, search found %d items\n", num_items);
692                     break;
693                 }
694                 case AVRCP_PDU_ID_GET_ITEM_ATTRIBUTES:
695                     packet[pos-1] = AVRCP_BROWSING_MEDIA_ELEMENT_ITEM_ATTRIBUTE;
696                     (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, packet+pos-1, size - pos + 1);
697                     break;
698 
699                 default:
700                     log_info(" not parsed pdu ID 0x%02x", browsing_connection->pdu_id);
701                     break;
702             }
703 
704             switch (avctp_packet_type){
705                 case AVRCP_SINGLE_PACKET:
706                 case AVRCP_END_PACKET:
707                     // printf("reset browsing connection state to OPENED\n");
708                     browsing_connection->state = AVCTP_CONNECTION_OPENED;
709                     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);
710                     break;
711                 default:
712                     break;
713             }
714             // printf(" paket done\n");
715             break;
716         }
717         case HCI_EVENT_PACKET:
718             switch (hci_event_packet_get_type(packet)){
719                 case L2CAP_EVENT_CAN_SEND_NOW:
720                     browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
721                     if (!browsing_connection) break;
722                     avrcp_browsing_controller_handle_can_send_now(browsing_connection);
723                     break;
724                 default:
725                     avrcp_browser_packet_handler(packet_type, channel, packet, size, &avrcp_controller_context);
726                     break;
727             }
728             break;
729 
730         default:
731             break;
732     }
733 }
734 
735 void avrcp_browsing_controller_init(void){
736     avrcp_controller_context.browsing_packet_handler = avrcp_browsing_controller_packet_handler;
737     l2cap_register_service(&avrcp_browsing_controller_packet_handler, PSM_AVCTP_BROWSING, 0xffff, LEVEL_2);
738 }
739 
740 void avrcp_browsing_controller_register_packet_handler(btstack_packet_handler_t callback){
741     if (callback == NULL){
742         log_error("avrcp_browsing_controller_register_packet_handler called with NULL callback");
743         return;
744     }
745     avrcp_controller_context.browsing_avrcp_callback = callback;
746 }
747 
748 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){
749     return avrcp_browsing_connect(bd_addr, &avrcp_controller_context, ertm_buffer, size, ertm_config, avrcp_browsing_cid);
750 }
751 
752 uint8_t avrcp_browsing_controller_disconnect(uint16_t avrcp_browsing_cid){
753     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
754     if (!avrcp_connection){
755         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
756         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
757     }
758     if (avrcp_connection->browsing_connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
759 
760     l2cap_disconnect(avrcp_connection->browsing_connection->l2cap_browsing_cid, 0);
761     return ERROR_CODE_SUCCESS;
762 }
763 
764 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){
765     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
766     if (!avrcp_connection){
767         log_error("avrcp_browsing_controller_decline_incoming_connection: could not find a connection.");
768         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
769     }
770     if (!avrcp_connection->browsing_connection){
771         log_error("avrcp_browsing_controller_decline_incoming_connection: no browsing connection.");
772         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
773     }
774 
775     if (avrcp_connection->browsing_connection->state != AVCTP_CONNECTION_W4_ERTM_CONFIGURATION){
776         log_error("avrcp_browsing_controller_decline_incoming_connection: browsing connection in a wrong state.");
777         return ERROR_CODE_COMMAND_DISALLOWED;
778     }
779 
780     avrcp_connection->browsing_connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
781     avrcp_connection->browsing_connection->ertm_buffer = ertm_buffer;
782     avrcp_connection->browsing_connection->ertm_buffer_size = size;
783     memcpy(&avrcp_connection->browsing_connection->ertm_config, ertm_config, sizeof(l2cap_ertm_config_t));
784     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);
785     return ERROR_CODE_SUCCESS;
786 }
787 
788 uint8_t avrcp_browsing_controller_decline_incoming_connection(uint16_t avrcp_browsing_cid){
789     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
790     if (!avrcp_connection){
791         log_error("avrcp_browsing_controller_decline_incoming_connection: could not find a connection.");
792         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
793     }
794     if (!avrcp_connection->browsing_connection) return ERROR_CODE_SUCCESS;
795     if (avrcp_connection->browsing_connection->state > AVCTP_CONNECTION_W4_ERTM_CONFIGURATION) return ERROR_CODE_COMMAND_DISALLOWED;
796 
797     l2cap_decline_connection(avrcp_connection->browsing_connection->l2cap_browsing_cid);
798     // free connection
799     btstack_memory_avrcp_browsing_connection_free(avrcp_connection->browsing_connection);
800     avrcp_connection->browsing_connection = NULL;
801     return ERROR_CODE_SUCCESS;
802 }
803 
804 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){
805     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
806     if (!avrcp_connection){
807         log_error("avrcp_browsing_controller_get_item_attributes: could not find a connection.");
808         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
809     }
810     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
811     if (connection->state != AVCTP_CONNECTION_OPENED){
812         log_error("avrcp_browsing_controller_get_item_attributes: connection in wrong state %d, expected %d.", connection->state, AVCTP_CONNECTION_OPENED);
813         return ERROR_CODE_COMMAND_DISALLOWED;
814     }
815 
816     connection->get_item_attributes = 1;
817     connection->scope = scope;
818     memcpy(connection->folder_uid, uid, 8);
819     connection->uid_counter = uid_counter;
820     connection->attr_bitmap = attr_bitmap;
821 
822     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
823     return ERROR_CODE_SUCCESS;
824 }
825 
826 /**
827  * @brief Retrieve a listing of the contents of a folder.
828  * @param scope    0-player list, 1-virtual file system, 2-search, 3-now playing
829  * @param start_item
830  * @param end_item
831  * @param attribute_count
832  * @param attribute_list
833  **/
834 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){
835     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
836     if (!avrcp_connection){
837         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
838         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
839     }
840     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
841     if (connection->state != AVCTP_CONNECTION_OPENED) {
842         log_error("avrcp_browsing_controller_get_folder_items: connection in wrong state %d, expected %d.", connection->state, AVCTP_CONNECTION_OPENED);
843         return ERROR_CODE_COMMAND_DISALLOWED;
844     }
845 
846     connection->get_folder_items = 1;
847     connection->scope = scope;
848     connection->start_item = start_item;
849     connection->end_item = end_item;
850     connection->attr_bitmap = attr_bitmap;
851 
852     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
853     return ERROR_CODE_SUCCESS;
854 }
855 
856 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){
857     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_MEDIA_PLAYER_LIST, start_item, end_item, attr_bitmap);
858 }
859 
860 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){
861     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 1, 0, 0xFFFFFFFF, attr_bitmap);
862     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_MEDIA_PLAYER_VIRTUAL_FILESYSTEM, start_item, end_item, attr_bitmap);
863 }
864 
865 uint8_t avrcp_browsing_controller_browse_media(uint16_t avrcp_browsing_cid, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
866     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 2, 0, 0xFFFFFFFF, 0, NULL);
867     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_SEARCH, start_item, end_item, attr_bitmap);
868 }
869 
870 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){
871     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_NOW_PLAYING, start_item, end_item, attr_bitmap);
872 }
873 
874 
875 uint8_t avrcp_browsing_controller_set_browsed_player(uint16_t avrcp_browsing_cid, uint16_t browsed_player_id){
876     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
877     if (!avrcp_connection){
878         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
879         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
880     }
881 
882     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
883     if (connection->state != AVCTP_CONNECTION_OPENED){
884         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
885         return ERROR_CODE_COMMAND_DISALLOWED;
886     }
887 
888     connection->set_browsed_player_id = 1;
889     connection->browsed_player_id = browsed_player_id;
890     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
891     return ERROR_CODE_SUCCESS;
892 }
893 
894 /**
895  * @brief Retrieve a listing of the contents of a folder.
896  * @param direction     0-folder up, 1-folder down
897  * @param folder_uid    8 bytes long
898  **/
899 uint8_t avrcp_browsing_controller_change_path(uint16_t avrcp_browsing_cid, uint8_t direction, uint8_t * folder_uid){
900     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
901     if (!avrcp_connection){
902         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
903         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
904     }
905 
906     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
907 
908     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
909         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
910         return ERROR_CODE_COMMAND_DISALLOWED;
911     }
912 
913     if (!connection->browsed_player_id){
914         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
915         return ERROR_CODE_COMMAND_DISALLOWED;
916     }
917     connection->change_path = 1;
918     connection->direction = direction;
919     memset(connection->folder_uid, 0, 8);
920     if (folder_uid){
921         memcpy(connection->folder_uid, folder_uid, 8);
922     }
923 
924     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
925     return ERROR_CODE_SUCCESS;
926 }
927 
928 uint8_t avrcp_browsing_controller_go_up_one_level(uint16_t avrcp_browsing_cid){
929     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 0, NULL);
930 }
931 
932 uint8_t avrcp_browsing_controller_go_down_one_level(uint16_t avrcp_browsing_cid, uint8_t * folder_uid){
933     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 1, folder_uid);
934 }
935 
936 uint8_t avrcp_browsing_controller_search(uint16_t avrcp_browsing_cid, uint16_t search_str_len, char * search_str){
937     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
938     if (!avrcp_connection){
939         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
940         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
941     }
942 
943     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
944 
945     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
946         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
947         return ERROR_CODE_COMMAND_DISALLOWED;
948     }
949 
950     if (!connection->browsed_player_id){
951         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
952         return ERROR_CODE_COMMAND_DISALLOWED;
953     }
954     if (!search_str || search_str_len == 0){
955         return AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND;
956     }
957 
958     connection->search = 1;
959 
960     connection->search_str_len = btstack_min(search_str_len, sizeof(connection->search_str)-1);
961     memset(connection->search_str, 0, sizeof(connection->search_str));
962     memcpy(connection->search_str, search_str, connection->search_str_len);
963     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
964     return ERROR_CODE_SUCCESS;
965 }
966 
967 uint8_t avrcp_browsing_controller_get_total_nr_items_for_scope(uint16_t avrcp_browsing_cid, avrcp_browsing_scope_t scope){
968     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
969     if (!avrcp_connection){
970         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
971         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
972     }
973 
974     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
975 
976     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
977         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
978         return ERROR_CODE_COMMAND_DISALLOWED;
979     }
980 
981     if (!connection->browsed_player_id){
982         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
983         return ERROR_CODE_COMMAND_DISALLOWED;
984     }
985     connection->get_total_nr_items = 1;
986     connection->get_total_nr_items_scope = scope;
987     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
988     return ERROR_CODE_SUCCESS;
989 }
990