xref: /btstack/src/classic/avrcp_browsing_controller.c (revision c37cd8f3d1350b92a2f66c31b2a5fcd75f8c91a4)
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 
45 #include "btstack.h"
46 #include "classic/avrcp.h"
47 #include "classic/avrcp_browsing_controller.h"
48 
49 void avrcp_browser_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avrcp_context_t * context);
50 static void avrcp_browsing_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
51 
52 static avrcp_connection_t * get_avrcp_connection_for_browsing_cid(uint16_t browsing_cid, avrcp_context_t * context){
53     btstack_linked_list_iterator_t it;
54     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
55     while (btstack_linked_list_iterator_has_next(&it)){
56         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
57         if (connection->avrcp_browsing_cid != browsing_cid) continue;
58         return connection;
59     }
60     return NULL;
61 }
62 
63 static avrcp_connection_t * get_avrcp_connection_for_browsing_l2cap_cid(uint16_t browsing_l2cap_cid, avrcp_context_t * context){
64     btstack_linked_list_iterator_t it;
65     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
66     while (btstack_linked_list_iterator_has_next(&it)){
67         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
68         if (connection->browsing_connection &&  connection->browsing_connection->l2cap_browsing_cid != browsing_l2cap_cid) continue;
69         return connection;
70     }
71     return NULL;
72 }
73 
74 static avrcp_browsing_connection_t * get_avrcp_browsing_connection_for_l2cap_cid(uint16_t l2cap_cid, avrcp_context_t * context){
75     btstack_linked_list_iterator_t it;
76     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *)  &context->connections);
77     while (btstack_linked_list_iterator_has_next(&it)){
78         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
79         if (connection->browsing_connection && connection->browsing_connection->l2cap_browsing_cid != l2cap_cid) continue;
80         return connection->browsing_connection;
81     }
82     return NULL;
83 }
84 
85 static void avrcp_emit_browsing_connection_established(btstack_packet_handler_t callback, uint16_t browsing_cid, bd_addr_t addr, uint8_t status){
86     if (!callback) return;
87     uint8_t event[12];
88     int pos = 0;
89     event[pos++] = HCI_EVENT_AVRCP_META;
90     event[pos++] = sizeof(event) - 2;
91     event[pos++] = AVRCP_SUBEVENT_BROWSING_CONNECTION_ESTABLISHED;
92     event[pos++] = status;
93     reverse_bd_addr(addr,&event[pos]);
94     pos += 6;
95     little_endian_store_16(event, pos, browsing_cid);
96     pos += 2;
97     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
98 }
99 
100 static void avrcp_emit_browsing_connection_closed(btstack_packet_handler_t callback, uint16_t browsing_cid){
101     if (!callback) return;
102     uint8_t event[5];
103     int pos = 0;
104     event[pos++] = HCI_EVENT_AVRCP_META;
105     event[pos++] = sizeof(event) - 2;
106     event[pos++] = AVRCP_SUBEVENT_BROWSING_CONNECTION_RELEASED;
107     little_endian_store_16(event, pos, browsing_cid);
108     pos += 2;
109     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
110 }
111 
112 static avrcp_browsing_connection_t * avrcp_browsing_create_connection(avrcp_connection_t * avrcp_connection){
113     avrcp_browsing_connection_t * connection = btstack_memory_avrcp_browsing_connection_get();
114     memset(connection, 0, sizeof(avrcp_browsing_connection_t));
115     connection->state = AVCTP_CONNECTION_IDLE;
116     connection->transaction_label = 0xFF;
117     avrcp_connection->avrcp_browsing_cid = avrcp_get_next_cid();
118     avrcp_connection->browsing_connection = connection;
119     return connection;
120 }
121 
122 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){
123     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_bd_addr(remote_addr, context);
124 
125     if (!avrcp_connection){
126         log_error("avrcp: there is no previously established AVRCP controller connection.");
127         return ERROR_CODE_COMMAND_DISALLOWED;
128     }
129 
130     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
131     if (connection){
132         log_error(" avrcp_browsing_connect connection exists.");
133         return ERROR_CODE_SUCCESS;
134     }
135 
136     connection = avrcp_browsing_create_connection(avrcp_connection);
137     if (!connection){
138         log_error("avrcp: could not allocate connection struct.");
139         return BTSTACK_MEMORY_ALLOC_FAILED;
140     }
141 
142     if (!browsing_cid) return L2CAP_LOCAL_CID_DOES_NOT_EXIST;
143 
144     *browsing_cid = avrcp_connection->avrcp_browsing_cid;
145     connection->ertm_buffer = ertm_buffer;
146     connection->ertm_buffer_size = size;
147     avrcp_connection->browsing_connection = connection;
148 
149     memcpy(&connection->ertm_config, ertm_config, sizeof(l2cap_ertm_config_t));
150 
151     return l2cap_create_ertm_channel(avrcp_browsing_controller_packet_handler, remote_addr, avrcp_connection->browsing_l2cap_psm,
152                     &connection->ertm_config, connection->ertm_buffer, connection->ertm_buffer_size, NULL);
153 
154 }
155 
156 void avrcp_browser_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avrcp_context_t * context){
157     UNUSED(channel);
158     UNUSED(size);
159     bd_addr_t event_addr;
160     uint16_t local_cid;
161     uint8_t  status;
162     avrcp_browsing_connection_t * connection = NULL;
163     avrcp_connection_t * avrcp_connection = NULL;
164 
165     if (packet_type != HCI_EVENT_PACKET) return;
166 
167     switch (hci_event_packet_get_type(packet)) {
168         case HCI_EVENT_DISCONNECTION_COMPLETE:
169             avrcp_emit_browsing_connection_closed(context->avrcp_callback, 0);
170             break;
171         case L2CAP_EVENT_INCOMING_CONNECTION:
172             l2cap_event_incoming_connection_get_address(packet, event_addr);
173             local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
174             avrcp_connection = get_avrcp_connection_for_bd_addr(event_addr, context);
175             if (!avrcp_connection) {
176                 log_error("No previously created AVRCP controller connections");
177                 l2cap_decline_connection(local_cid);
178                 break;
179             }
180             connection = avrcp_browsing_create_connection(avrcp_connection);
181             avrcp_connection->browsing_connection = connection;
182             connection->l2cap_browsing_cid = local_cid;
183             connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
184             log_info("L2CAP_EVENT_INCOMING_CONNECTION browsing_cid 0x%02x, l2cap_signaling_cid 0x%02x", avrcp_connection->avrcp_browsing_cid, connection->l2cap_browsing_cid);
185             // l2cap_accept_connection(local_cid);
186             log_error("L2CAP Accepting incoming connection request in ERTM.");
187             l2cap_accept_ertm_connection(local_cid, &connection->ertm_config, connection->ertm_buffer, connection->ertm_buffer_size);
188             break;
189 
190         case L2CAP_EVENT_CHANNEL_OPENED:
191             l2cap_event_channel_opened_get_address(packet, event_addr);
192             status = l2cap_event_channel_opened_get_status(packet);
193             local_cid = l2cap_event_channel_opened_get_local_cid(packet);
194 
195             avrcp_connection = get_avrcp_connection_for_bd_addr(event_addr, context);
196             if (!avrcp_connection){
197                 log_error("Failed to find AVRCP connection for bd_addr %s", bd_addr_to_str(event_addr));
198                 avrcp_emit_browsing_connection_established(context->avrcp_callback, local_cid, event_addr, L2CAP_LOCAL_CID_DOES_NOT_EXIST);
199                 l2cap_disconnect(local_cid, 0); // reason isn't used
200                 break;
201             }
202 
203             connection = avrcp_connection->browsing_connection;
204             if (!connection){
205                 log_error("Failed to alloc AVRCP connection structure");
206                 avrcp_emit_browsing_connection_established(context->avrcp_callback, local_cid, event_addr, BTSTACK_MEMORY_ALLOC_FAILED);
207                 l2cap_disconnect(local_cid, 0); // reason isn't used
208                 break;
209             }
210 
211             if (status != ERROR_CODE_SUCCESS){
212                 log_info("L2CAP connection to connection %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
213                 avrcp_emit_browsing_connection_established(context->avrcp_callback, avrcp_connection->avrcp_browsing_cid, event_addr, status);
214                 btstack_memory_avrcp_browsing_connection_free(connection);
215                 avrcp_connection->browsing_connection = NULL;
216                 break;
217             }
218             connection->l2cap_browsing_cid = local_cid;
219 
220             log_info("L2CAP_EVENT_CHANNEL_OPENED browsing cid 0x%02x, l2cap cid 0x%02x", avrcp_connection->avrcp_browsing_cid, connection->l2cap_browsing_cid);
221             connection->state = AVCTP_CONNECTION_OPENED;
222             avrcp_emit_browsing_connection_established(context->avrcp_callback, avrcp_connection->avrcp_browsing_cid, event_addr, ERROR_CODE_SUCCESS);
223             break;
224 
225         case L2CAP_EVENT_CHANNEL_CLOSED:
226             // data: event (8), len(8), channel (16)
227             local_cid = l2cap_event_channel_closed_get_local_cid(packet);
228             avrcp_connection = get_avrcp_connection_for_browsing_l2cap_cid(local_cid, context);
229 
230             if (avrcp_connection && avrcp_connection->browsing_connection){
231                 avrcp_emit_browsing_connection_closed(context->avrcp_callback, avrcp_connection->avrcp_browsing_cid);
232                 // free connection
233                 btstack_memory_avrcp_browsing_connection_free(avrcp_connection->browsing_connection);
234                 avrcp_connection->browsing_connection = NULL;
235                 break;
236             }
237             break;
238         default:
239             break;
240     }
241 }
242 
243 static int avrcp_browsing_controller_send_get_folder_items_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
244     uint8_t command[100];
245     int pos = 0;
246     // transport header
247     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
248     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
249     // Profile IDentifier (PID)
250     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
251     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
252     command[pos++] = AVRCP_PDU_ID_GET_FOLDER_ITEMS;
253 
254     uint32_t attribute_count = 0;
255     uint32_t attributes_to_copy = 0;
256 
257     switch (connection->attr_bitmap){
258         case AVRCP_MEDIA_ATTR_NONE:
259             attribute_count = AVRCP_MEDIA_ATTR_NONE; // 0xFFFFFFFF
260             break;
261         case AVRCP_MEDIA_ATTR_ALL:
262             attribute_count = AVRCP_MEDIA_ATTR_ALL;  // 0
263             break;
264         default:
265             attribute_count = count_set_bits_uint32(connection->attr_bitmap & 0xff);
266             attributes_to_copy = attribute_count;
267             break;
268     }
269 
270     big_endian_store_16(command, pos, 10 + attribute_count);
271     pos += 2;
272     command[pos++] = connection->scope;
273     big_endian_store_32(command, pos, connection->start_item);
274     pos += 4;
275     big_endian_store_32(command, pos, connection->end_item);
276     pos += 4;
277     command[pos++] = attribute_count;
278 
279     int bit_position = 1;
280     while (attributes_to_copy){
281         if (connection->attr_bitmap & (1 << bit_position)){
282             big_endian_store_32(command, pos, bit_position);
283             pos += 4;
284             attributes_to_copy--;
285         }
286         bit_position++;
287     }
288 
289     return l2cap_send(cid, command, pos);
290 }
291 
292 static int avrcp_browsing_controller_send_change_path_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
293     uint8_t command[100];
294     int pos = 0;
295     // transport header
296     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
297     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
298     // Profile IDentifier (PID)
299     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
300     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
301     command[pos++] = AVRCP_PDU_ID_CHANGE_PATH;
302 
303     big_endian_store_16(command, pos, 11);
304     pos += 2;
305     big_endian_store_16(command, pos, connection->browsed_player_uid_counter);
306     pos += 2;
307     command[pos++] = connection->direction;
308     memcpy(command+pos, connection->folder_uid, 8);
309     pos += 8;
310     return l2cap_send(cid, command, pos);
311 }
312 
313 static int avrcp_browsing_controller_send_set_browsed_player_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
314     uint8_t command[100];
315     int pos = 0;
316     // transport header
317     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
318     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
319     // Profile IDentifier (PID)
320     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
321     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
322     command[pos++] = AVRCP_PDU_ID_SET_BROWSED_PLAYER;
323 
324     big_endian_store_16(command, pos, 2);
325     pos += 2;
326     big_endian_store_16(command, pos, connection->browsed_player_id);
327     pos += 2;
328     return l2cap_send(cid, command, pos);
329 }
330 
331 static int avrcp_browsing_controller_send_set_addressed_player_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
332     uint8_t command[100];
333     int pos = 0;
334     // transport header
335     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
336     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
337     // Profile IDentifier (PID)
338     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
339     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
340     command[pos++] = AVRCP_PDU_ID_SET_ADDRESSED_PLAYER;
341 
342     big_endian_store_16(command, pos, 2);
343     pos += 2;
344     big_endian_store_16(command, pos, connection->addressed_player_id);
345     pos += 2;
346     return l2cap_send(cid, command, pos);
347 }
348 
349 static void avrcp_browsing_controller_handle_can_send_now(avrcp_browsing_connection_t * connection){
350     switch (connection->state){
351         case AVCTP_CONNECTION_OPENED:
352             if (connection->get_folder_item){
353                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
354                 connection->get_folder_item = 0;
355                 avrcp_browsing_controller_send_get_folder_items_cmd(connection->l2cap_browsing_cid, connection);
356                 break;
357             }
358             if (connection->change_path){
359                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
360                 connection->change_path = 0;
361                 avrcp_browsing_controller_send_change_path_cmd(connection->l2cap_browsing_cid, connection);
362                 break;
363             }
364 
365             if (connection->set_browsed_player_id){
366                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
367                 connection->set_browsed_player_id = 0;
368                 avrcp_browsing_controller_send_set_browsed_player_cmd(connection->l2cap_browsing_cid, connection);
369                 break;
370             }
371 
372             if (connection->set_addressed_player_id){
373                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
374                 connection->set_addressed_player_id = 0;
375                 avrcp_browsing_controller_send_set_addressed_player_cmd(connection->l2cap_browsing_cid, connection);
376                 break;
377             }
378         default:
379             return;
380     }
381 }
382 
383 static void avrcp_browsing_controller_emit_done(btstack_packet_handler_t callback, uint16_t browsing_cid, uint8_t browsing_status, uint8_t bluetooth_status){
384     if (!callback) return;
385     uint8_t event[6];
386     int pos = 0;
387     event[pos++] = HCI_EVENT_AVRCP_META;
388     event[pos++] = sizeof(event) - 2;
389     event[pos++] = AVRCP_SUBEVENT_BROWSING_MEDIA_ITEM_DONE;
390     little_endian_store_16(event, pos, browsing_cid);
391     pos += 2;
392     event[pos++] = browsing_status;
393     event[pos++] = bluetooth_status;
394     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
395 }
396 
397 static void avrcp_browsing_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
398     avrcp_browsing_connection_t * browsing_connection;
399 
400     switch (packet_type) {
401         case L2CAP_DATA_PACKET:{
402             browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
403             if (!browsing_connection) break;
404             browsing_connection->state = AVCTP_CONNECTION_OPENED;
405 
406             int pos = 3;
407             if (size < pos + 4){
408                 avrcp_browsing_controller_emit_done(avrcp_controller_context.avrcp_callback, channel, AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND, ERROR_CODE_SUCCESS);
409                 break;
410             }
411 
412             avrcp_pdu_id_t pdu_id = packet[pos++];
413             uint16_t length = big_endian_read_16(packet, pos);
414             pos += 2;
415             if (size + pos < length){
416                 avrcp_browsing_controller_emit_done(avrcp_controller_context.avrcp_callback, channel, AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND, ERROR_CODE_SUCCESS);
417                 break;
418             }
419 
420             uint8_t browsing_status = packet[pos++];
421             if (browsing_status != AVRCP_BROWSING_ERROR_CODE_SUCCESS){
422                 avrcp_browsing_controller_emit_done(avrcp_controller_context.avrcp_callback, channel, browsing_status, ERROR_CODE_SUCCESS);
423                 break;
424             }
425 
426             uint32_t i;
427             switch(pdu_id){
428                 case AVRCP_PDU_ID_CHANGE_PATH:
429                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:
430                     break;
431                 case AVRCP_PDU_ID_SET_BROWSED_PLAYER:{
432                     browsing_connection->browsed_player_uid_counter = big_endian_read_16(packet, pos);
433                     pos += 2;
434                     uint32_t num_items = big_endian_read_32(packet, pos);
435                     pos += 4;
436 
437                     for (i = 0; i < num_items; i++){
438                         uint16_t browsable_item_length = 5 + big_endian_read_16(packet, pos+3);
439                         // reuse byte to put the new type AVRCP_BROWSING_MEDIA_ROOT_FOLDER
440                         packet[pos-1] = AVRCP_BROWSING_MEDIA_ROOT_FOLDER;
441                         (*avrcp_controller_context.avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, packet+pos, browsable_item_length+1);
442                         pos += browsable_item_length;
443                     }
444                     break;
445                 }
446                 case AVRCP_PDU_ID_GET_FOLDER_ITEMS:{
447                     // uint16_t uid_counter = big_endian_read_16(packet, pos);
448                     pos += 2;
449                     uint16_t num_items = big_endian_read_16(packet, pos);
450                     pos += 2;
451 
452                     for (i = 0; i < num_items; i++){
453                         uint16_t browsable_item_length = 3 + big_endian_read_16(packet, pos+1);
454                         (*avrcp_controller_context.avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, packet+pos, browsable_item_length);
455                         pos += browsable_item_length;
456                     }
457                     break;
458                 }
459                 default:
460                     return;
461             }
462             avrcp_browsing_controller_emit_done(avrcp_controller_context.avrcp_callback, channel, browsing_status, ERROR_CODE_SUCCESS);
463         break;
464         }
465         case HCI_EVENT_PACKET:
466             switch (hci_event_packet_get_type(packet)){
467                 case L2CAP_EVENT_CAN_SEND_NOW:
468                     browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
469                     if (!browsing_connection) break;
470                     avrcp_browsing_controller_handle_can_send_now(browsing_connection);
471                     break;
472             default:
473                 avrcp_browser_packet_handler(packet_type, channel, packet, size, &avrcp_controller_context);
474                 break;
475         }
476         default:
477             break;
478     }
479 }
480 
481 void avrcp_browsing_controller_init(void){
482     avrcp_controller_context.browsing_packet_handler = avrcp_browsing_controller_packet_handler;
483     l2cap_register_service(&avrcp_browsing_controller_packet_handler, BLUETOOTH_PROTOCOL_AVCTP, 0xffff, LEVEL_0);
484 }
485 
486 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){
487     return avrcp_browsing_connect(bd_addr, &avrcp_controller_context, ertm_buffer, size, ertm_config, avrcp_browsing_cid);
488 }
489 
490 uint8_t avrcp_browsing_controller_disconnect(uint16_t avrcp_browsing_cid){
491     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
492     if (!avrcp_connection){
493         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
494         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
495     }
496     if (avrcp_connection->browsing_connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
497 
498     l2cap_disconnect(avrcp_connection->browsing_connection->l2cap_browsing_cid, 0);
499     return ERROR_CODE_SUCCESS;
500 }
501 
502 /**
503  * @brief Retrieve a listing of the contents of a folder.
504  * @param scope    0-player list, 1-virtual file system, 2-search, 3-now playing
505  * @param start_item
506  * @param end_item
507  * @param attribute_count
508  * @param attribute_list
509  **/
510 static uint8_t avrcp_browsing_controller_get_folder_items(uint16_t avrcp_browsing_cid, uint8_t scope, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
511     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
512     if (!avrcp_connection){
513         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
514         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
515     }
516     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
517     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
518 
519     connection->get_folder_item = 1;
520     connection->scope = scope;
521     connection->start_item = start_item;
522     connection->end_item = end_item;
523     connection->attr_bitmap = attr_bitmap;
524 
525     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
526     return ERROR_CODE_SUCCESS;
527 }
528 
529 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){
530     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 0, start_item, end_item, attr_bitmap);
531 }
532 
533 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){
534     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 1, 0, 0xFFFFFFFF, attr_bitmap);
535     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 1, start_item, end_item, attr_bitmap);
536 }
537 
538 uint8_t avrcp_browsing_controller_browse_media(uint16_t avrcp_browsing_cid, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
539     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 2, 0, 0xFFFFFFFF, 0, NULL);
540     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 2, start_item, end_item, attr_bitmap);
541 }
542 
543 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){
544     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 3, start_item, end_item, attr_bitmap);
545 }
546 
547 
548 uint8_t avrcp_browsing_controller_set_browsed_player(uint16_t avrcp_browsing_cid, uint16_t browsed_player_id){
549     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
550     if (!avrcp_connection){
551         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
552         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
553     }
554 
555     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
556     if (connection->state != AVCTP_CONNECTION_OPENED){
557         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
558         return ERROR_CODE_COMMAND_DISALLOWED;
559     }
560 
561     connection->set_browsed_player_id = 1;
562     connection->browsed_player_id = browsed_player_id;
563     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
564     return ERROR_CODE_SUCCESS;
565 }
566 
567 uint8_t avrcp_browsing_controller_set_addressed_player(uint16_t avrcp_browsing_cid, uint16_t addressed_player_id){
568     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
569     if (!avrcp_connection){
570         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
571         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
572     }
573 
574     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
575     if (connection->state != AVCTP_CONNECTION_OPENED){
576         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
577         return ERROR_CODE_COMMAND_DISALLOWED;
578     }
579 
580     connection->set_addressed_player_id = 1;
581     connection->addressed_player_id = addressed_player_id;
582     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
583     return ERROR_CODE_SUCCESS;
584 }
585 
586 /**
587  * @brief Retrieve a listing of the contents of a folder.
588  * @param direction     0-folder up, 1-folder down
589  * @param folder_uid    8 bytes long
590  **/
591 uint8_t avrcp_browsing_controller_change_path(uint16_t avrcp_browsing_cid, uint8_t direction, uint8_t * folder_uid){
592     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
593     if (!avrcp_connection){
594         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
595         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
596     }
597 
598     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
599     if (connection->state != AVCTP_CONNECTION_OPENED){
600         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
601         return ERROR_CODE_COMMAND_DISALLOWED;
602     }
603 
604     if (!connection->browsed_player_id){
605         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
606         return ERROR_CODE_COMMAND_DISALLOWED;
607     }
608 
609     connection->change_path = 1;
610     connection->direction = direction;
611     memcpy(connection->folder_uid, folder_uid, 8);
612     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
613     return ERROR_CODE_SUCCESS;
614 }
615 
616 uint8_t avrcp_browsing_controller_go_up_one_level(uint16_t avrcp_browsing_cid){
617     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 0, 0);
618 }
619 
620 uint8_t avrcp_browsing_controller_go_down_one_level(uint16_t avrcp_browsing_cid, uint8_t * folder_uid){
621     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 1, folder_uid);
622 }
623