xref: /btstack/src/classic/avrcp_browsing_controller.c (revision 73fba53895554e4b0e03749402e05b550ed1528f)
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 #define PSM_AVCTP_BROWSING              0x001b
50 
51 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) return L2CAP_LOCAL_CID_DOES_NOT_EXIST;
159 
160     *browsing_cid = avrcp_connection->avrcp_browsing_cid;
161     connection->ertm_buffer = ertm_buffer;
162     connection->ertm_buffer_size = size;
163     avrcp_connection->browsing_connection = connection;
164 
165     memcpy(&connection->ertm_config, ertm_config, sizeof(l2cap_ertm_config_t));
166 
167     return l2cap_create_ertm_channel(avrcp_browsing_controller_packet_handler, remote_addr, avrcp_connection->browsing_l2cap_psm,
168                     &connection->ertm_config, connection->ertm_buffer, connection->ertm_buffer_size, NULL);
169 
170 }
171 
172 void avrcp_browser_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avrcp_context_t * context){
173     UNUSED(channel);
174     UNUSED(size);
175     bd_addr_t event_addr;
176     uint16_t local_cid;
177     uint8_t  status;
178     avrcp_browsing_connection_t * browsing_connection = NULL;
179     avrcp_connection_t * avrcp_connection = NULL;
180 
181     if (packet_type != HCI_EVENT_PACKET) return;
182 
183     switch (hci_event_packet_get_type(packet)) {
184         case HCI_EVENT_DISCONNECTION_COMPLETE:
185             avrcp_emit_browsing_connection_closed(context->browsing_avrcp_callback, 0);
186             break;
187         case L2CAP_EVENT_INCOMING_CONNECTION:
188             l2cap_event_incoming_connection_get_address(packet, event_addr);
189             local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
190             avrcp_connection = get_avrcp_connection_for_bd_addr(event_addr, context);
191             if (!avrcp_connection) {
192                 log_error("No previously created AVRCP controller connections");
193                 l2cap_decline_connection(local_cid);
194                 break;
195             }
196             browsing_connection = avrcp_browsing_create_connection(avrcp_connection);
197             browsing_connection->l2cap_browsing_cid = local_cid;
198             browsing_connection->state = AVCTP_CONNECTION_W4_ERTM_CONFIGURATION;
199             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);
200             avrcp_emit_incoming_browsing_connection(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid, event_addr);
201             break;
202 
203         case L2CAP_EVENT_CHANNEL_OPENED:
204             l2cap_event_channel_opened_get_address(packet, event_addr);
205             status = l2cap_event_channel_opened_get_status(packet);
206             local_cid = l2cap_event_channel_opened_get_local_cid(packet);
207 
208             avrcp_connection = get_avrcp_connection_for_bd_addr(event_addr, context);
209             if (!avrcp_connection){
210                 log_error("Failed to find AVRCP connection for bd_addr %s", bd_addr_to_str(event_addr));
211                 avrcp_emit_browsing_connection_established(context->browsing_avrcp_callback, local_cid, event_addr, L2CAP_LOCAL_CID_DOES_NOT_EXIST);
212                 l2cap_disconnect(local_cid, 0); // reason isn't used
213                 break;
214             }
215 
216             browsing_connection = avrcp_connection->browsing_connection;
217             if (status != ERROR_CODE_SUCCESS){
218                 log_info("L2CAP connection to connection %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
219                 avrcp_emit_browsing_connection_established(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid, event_addr, status);
220                 btstack_memory_avrcp_browsing_connection_free(browsing_connection);
221                 avrcp_connection->browsing_connection = NULL;
222                 break;
223             }
224             if (browsing_connection->state != AVCTP_CONNECTION_W4_L2CAP_CONNECTED) break;
225 
226             browsing_connection->l2cap_browsing_cid = local_cid;
227 
228             log_info("L2CAP_EVENT_CHANNEL_OPENED browsing cid 0x%02x, l2cap cid 0x%02x", avrcp_connection->avrcp_browsing_cid, browsing_connection->l2cap_browsing_cid);
229             browsing_connection->state = AVCTP_CONNECTION_OPENED;
230             avrcp_emit_browsing_connection_established(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid, event_addr, ERROR_CODE_SUCCESS);
231             break;
232 
233         case L2CAP_EVENT_CHANNEL_CLOSED:
234             // data: event (8), len(8), channel (16)
235             local_cid = l2cap_event_channel_closed_get_local_cid(packet);
236             avrcp_connection = get_avrcp_connection_for_browsing_l2cap_cid(local_cid, context);
237 
238             if (avrcp_connection && avrcp_connection->browsing_connection){
239                 avrcp_emit_browsing_connection_closed(context->browsing_avrcp_callback, avrcp_connection->avrcp_browsing_cid);
240                 // free connection
241                 btstack_memory_avrcp_browsing_connection_free(avrcp_connection->browsing_connection);
242                 avrcp_connection->browsing_connection = NULL;
243                 break;
244             }
245             break;
246         default:
247             break;
248     }
249 }
250 
251 static int avrcp_browsing_controller_send_get_folder_items_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
252     uint8_t command[100];
253     int pos = 0;
254     // transport header
255     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
256     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
257     // Profile IDentifier (PID)
258     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
259     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
260     command[pos++] = AVRCP_PDU_ID_GET_FOLDER_ITEMS;
261 
262     uint32_t attribute_count = 0;
263     uint32_t attributes_to_copy = 0;
264 
265     switch (connection->attr_bitmap){
266         case AVRCP_MEDIA_ATTR_NONE:
267             attribute_count = AVRCP_MEDIA_ATTR_NONE; // 0xFFFFFFFF
268             break;
269         case AVRCP_MEDIA_ATTR_ALL:
270             attribute_count = AVRCP_MEDIA_ATTR_ALL;  // 0
271             break;
272         default:
273             attribute_count = count_set_bits_uint32(connection->attr_bitmap & 0xff);
274             attributes_to_copy = attribute_count;
275             break;
276     }
277 
278     big_endian_store_16(command, pos, 10 + attribute_count);
279     pos += 2;
280     command[pos++] = connection->scope;
281     big_endian_store_32(command, pos, connection->start_item);
282     pos += 4;
283     big_endian_store_32(command, pos, connection->end_item);
284     pos += 4;
285     command[pos++] = attribute_count;
286 
287     int bit_position = 1;
288     while (attributes_to_copy){
289         if (connection->attr_bitmap & (1 << bit_position)){
290             big_endian_store_32(command, pos, bit_position);
291             pos += 4;
292             attributes_to_copy--;
293         }
294         bit_position++;
295     }
296 
297     return l2cap_send(cid, command, pos);
298 }
299 
300 static int avrcp_browsing_controller_send_change_path_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
301     uint8_t command[100];
302     int pos = 0;
303     // transport header
304     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
305     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
306     // Profile IDentifier (PID)
307     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
308     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
309     command[pos++] = AVRCP_PDU_ID_CHANGE_PATH;
310 
311     big_endian_store_16(command, pos, 11);
312     pos += 2;
313     big_endian_store_16(command, pos, connection->browsed_player_uid_counter);
314     pos += 2;
315     command[pos++] = connection->direction;
316     memcpy(command+pos, connection->folder_uid, 8);
317     pos += 8;
318     return l2cap_send(cid, command, pos);
319 }
320 
321 static int avrcp_browsing_controller_send_search_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
322     uint8_t command[100];
323     int pos = 0;
324     // transport header
325     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
326     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
327     // Profile IDentifier (PID)
328     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
329     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
330     command[pos++] = AVRCP_PDU_ID_SEARCH;
331 
332     big_endian_store_16(command, pos, 4 + connection->search_str_len);
333     pos += 2;
334 
335     big_endian_store_16(command, pos, 0x006A);
336     pos += 2;
337     big_endian_store_16(command, pos, connection->search_str_len);
338     pos += 2;
339 
340     memcpy(command+pos,connection->search_str, connection->search_str_len);
341     pos += connection->search_str_len;
342     return l2cap_send(cid, command, pos);
343 }
344 
345 static int avrcp_browsing_controller_send_set_browsed_player_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
346     uint8_t command[100];
347     int pos = 0;
348     // transport header
349     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
350     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
351     // Profile IDentifier (PID)
352     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
353     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
354     command[pos++] = AVRCP_PDU_ID_SET_BROWSED_PLAYER;
355 
356     big_endian_store_16(command, pos, 2);
357     pos += 2;
358     big_endian_store_16(command, pos, connection->browsed_player_id);
359     pos += 2;
360     return l2cap_send(cid, command, pos);
361 }
362 
363 static int avrcp_browsing_controller_send_set_addressed_player_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_SET_ADDRESSED_PLAYER;
373 
374     big_endian_store_16(command, pos, 2);
375     pos += 2;
376     big_endian_store_16(command, pos, connection->addressed_player_id);
377     pos += 2;
378     return l2cap_send(cid, command, pos);
379 }
380 
381 static void avrcp_browsing_controller_handle_can_send_now(avrcp_browsing_connection_t * connection){
382     switch (connection->state){
383         case AVCTP_CONNECTION_OPENED:
384             if (connection->set_browsed_player_id){
385                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
386                 connection->set_browsed_player_id = 0;
387                 avrcp_browsing_controller_send_set_browsed_player_cmd(connection->l2cap_browsing_cid, connection);
388                 break;
389             }
390 
391             if (connection->set_addressed_player_id){
392                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
393                 connection->set_addressed_player_id = 0;
394                 avrcp_browsing_controller_send_set_addressed_player_cmd(connection->l2cap_browsing_cid, connection);
395                 break;
396             }
397 
398             if (connection->get_folder_item){
399                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
400                 connection->get_folder_item = 0;
401                 avrcp_browsing_controller_send_get_folder_items_cmd(connection->l2cap_browsing_cid, connection);
402                 break;
403             }
404             if (connection->change_path){
405                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
406                 connection->change_path = 0;
407                 avrcp_browsing_controller_send_change_path_cmd(connection->l2cap_browsing_cid, connection);
408                 break;
409             }
410             if (connection->search){
411                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
412                 connection->search = 0;
413                 avrcp_browsing_controller_send_search_cmd(connection->l2cap_browsing_cid, connection);
414                 break;
415             }
416             break;
417         default:
418             return;
419     }
420 }
421 
422 
423 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){
424     if (!callback) return;
425     uint8_t event[9];
426     int pos = 0;
427     event[pos++] = HCI_EVENT_AVRCP_META;
428     event[pos++] = sizeof(event) - 2;
429     event[pos++] = AVRCP_SUBEVENT_BROWSING_DONE;
430     little_endian_store_16(event, pos, browsing_cid);
431     pos += 2;
432     little_endian_store_16(event, pos, uid_counter);
433     pos += 2;
434     event[pos++] = browsing_status;
435     event[pos++] = bluetooth_status;
436     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
437 }
438 
439 static void avrcp_browsing_controller_emit_done(btstack_packet_handler_t callback, uint16_t browsing_cid, uint8_t browsing_status, uint8_t bluetooth_status){
440     avrcp_browsing_controller_emit_done_with_uid_counter(callback, browsing_cid, 0, browsing_status, bluetooth_status);
441 }
442 
443 static void avrcp_browsing_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
444     avrcp_browsing_connection_t * browsing_connection;
445 
446     switch (packet_type) {
447         case L2CAP_DATA_PACKET:{
448             browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
449             if (!browsing_connection) break;
450             int pos = 0;
451             uint8_t transport_header = packet[pos++];
452             // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
453             // uint8_t transaction_label = transport_header >> 4;
454             avrcp_packet_type_t avctp_packet_type = (transport_header & 0x0F) >> 2;
455 
456             avrcp_pdu_id_t pdu_id;
457             uint8_t browsing_status;
458             uint16_t uid_counter;
459             if (!browsing_connection->fragmented){
460                 browsing_connection->state = AVCTP_CONNECTION_OPENED;
461                 // printf_hexdump(packet, size);
462                 // uint8_t frame_type = (transport_header & 0x03) >> 1;
463                 // uint8_t ipid = transport_header & 0x01;
464                 pos += 2;
465                 browsing_connection->num_packets = 1;
466                 if (avctp_packet_type == AVRCP_START_PACKET){
467                     browsing_connection->num_packets = packet[pos++];
468                 }
469 
470                 if (pos + 4 > size){
471                     avrcp_browsing_controller_emit_done(avrcp_controller_context.browsing_avrcp_callback, channel, AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND, ERROR_CODE_SUCCESS);
472                     return;
473                 }
474                 pdu_id = packet[pos++];
475                 // uint16_t length = big_endian_read_16(packet, pos);
476                 pos += 2;
477                 browsing_status = packet[pos++];
478                 if (browsing_status != AVRCP_BROWSING_ERROR_CODE_SUCCESS){
479                     avrcp_browsing_controller_emit_done(avrcp_controller_context.browsing_avrcp_callback, channel, browsing_status, ERROR_CODE_SUCCESS);
480                     return;
481                 }
482                 uid_counter =  big_endian_read_16(packet, pos);
483                 pos += 2;
484             } else {
485                 pdu_id = browsing_connection->fragmented_pdu_id;
486                 browsing_status = browsing_connection->fragmented_browsing_status;
487                 uid_counter = browsing_connection->fragmented_uid_counter;
488             }
489 
490             uint32_t i;
491             switch(pdu_id){
492                 case AVRCP_PDU_ID_CHANGE_PATH:
493                     printf("AVRCP_PDU_ID_CHANGE_PATH \n");
494                     break;
495                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:
496                     printf("AVRCP_PDU_ID_SET_ADDRESSED_PLAYER \n");
497                     break;
498                 case AVRCP_PDU_ID_SET_BROWSED_PLAYER:{
499                     browsing_connection->browsed_player_uid_counter = uid_counter;
500                     // uint32_t num_items = big_endian_read_32(packet, pos);
501                     pos += 4;
502                     // uint16_t charset = big_endian_read_16(packet, pos);
503                     pos += 2;
504                     uint8_t folder_depth = packet[pos++];
505 
506                     for (i = 0; i < folder_depth; i++){
507                         uint16_t folder_name_length = big_endian_read_16(packet, pos);
508                         pos += 2;
509                         // reuse packet and add data type as a header
510                         packet[pos-1] = AVRCP_BROWSING_MEDIA_ROOT_FOLDER;
511                         (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, packet+pos-1, folder_name_length+1);
512                         pos += folder_name_length;
513                     }
514                     if (avctp_packet_type == AVRCP_SINGLE_PACKET || avctp_packet_type == AVRCP_END_PACKET){
515                         avrcp_browsing_controller_emit_done_with_uid_counter(avrcp_controller_context.browsing_avrcp_callback, channel, browsing_connection->browsed_player_uid_counter, browsing_status, ERROR_CODE_SUCCESS);
516                     }
517                     break;
518                 }
519                 case AVRCP_PDU_ID_GET_FOLDER_ITEMS:{
520                     printf("AVRCP_PDU_ID_GET_FOLDER_ITEMS\n");
521                     // send UID counter with done
522                     if (!browsing_connection->fragmented){
523                         browsing_connection->num_items = big_endian_read_16(packet, pos);
524                         pos += 2;
525                     }
526                     while (pos < size){
527                         uint8_t header_size = 1;
528                         if (browsing_connection->fragment_size == 0){
529                             browsing_connection->item_type = packet[pos++];
530                             browsing_connection->item_length = big_endian_read_16(packet, pos);
531                             pos += 2;
532                             // reuse packet and add data type as a header
533                             packet[pos-1] = browsing_connection->item_type;
534 
535                             if (browsing_connection->item_length + pos > size) {
536                                 browsing_connection->fragment_size = size - pos;
537                                 browsing_connection->fragment[0] = browsing_connection->item_type;
538                                 memcpy(&browsing_connection->fragment[header_size], &packet[pos], browsing_connection->fragment_size);
539                                 break;
540                             }
541                             (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, &packet[pos-header_size], browsing_connection->item_length+header_size);
542                             browsing_connection->num_items--;
543                             pos += browsing_connection->item_length;
544                         } else {
545                             uint16_t remaining_bytes_to_copy = browsing_connection->item_length - browsing_connection->fragment_size;
546                             if (remaining_bytes_to_copy + pos > size) {
547                                 memcpy(&browsing_connection->fragment[browsing_connection->fragment_size+1], &packet[pos], size - pos);
548                                 browsing_connection->fragment_size += size - pos;
549                                 break;
550                             }
551                             memcpy(&browsing_connection->fragment[browsing_connection->fragment_size+1], &packet[pos], remaining_bytes_to_copy);
552                             (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, browsing_connection->fragment, browsing_connection->item_length+1);
553                             browsing_connection->num_items--;
554                             browsing_connection->fragment_size = 0;
555                             pos += remaining_bytes_to_copy;
556                         }
557                     }
558                     break;
559                 }
560                 case AVRCP_PDU_ID_SEARCH:{
561                         uint32_t num_items = big_endian_read_32(packet, pos);
562                         printf("TODO: send as event, search found %d items\n", num_items);
563                         break;
564                     }
565                 default:
566                     break;
567             }
568 
569             switch (avctp_packet_type){
570                 case AVRCP_SINGLE_PACKET:
571                 case AVRCP_END_PACKET:
572                     browsing_connection->state = AVCTP_CONNECTION_OPENED;
573                     browsing_connection->fragmented = 0;
574                     browsing_connection->num_items = 0;
575                     browsing_connection->fragment_size = 0;
576                     avrcp_browsing_controller_emit_done_with_uid_counter(avrcp_controller_context.browsing_avrcp_callback, channel, uid_counter, browsing_status, ERROR_CODE_SUCCESS);
577                     break;
578                 case AVRCP_START_PACKET:
579                     browsing_connection->fragmented = 1;
580                     browsing_connection->fragmented_pdu_id = pdu_id;
581                     browsing_connection->fragmented_browsing_status = browsing_status;
582                     break;
583                 case AVRCP_CONTINUE_PACKET:
584                     browsing_connection->fragmented = 1;
585                     break;
586             }
587             break;
588         }
589         case HCI_EVENT_PACKET:
590             switch (hci_event_packet_get_type(packet)){
591                 case L2CAP_EVENT_CAN_SEND_NOW:
592                     browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
593                     if (!browsing_connection) break;
594                     avrcp_browsing_controller_handle_can_send_now(browsing_connection);
595                     break;
596             default:
597                 avrcp_browser_packet_handler(packet_type, channel, packet, size, &avrcp_controller_context);
598                 break;
599         }
600         default:
601             break;
602     }
603 }
604 
605 void avrcp_browsing_controller_init(void){
606     avrcp_controller_context.browsing_packet_handler = avrcp_browsing_controller_packet_handler;
607     l2cap_register_service(&avrcp_browsing_controller_packet_handler, PSM_AVCTP_BROWSING, 0xffff, LEVEL_0);
608 }
609 
610 void avrcp_browsing_controller_register_packet_handler(btstack_packet_handler_t callback){
611     if (callback == NULL){
612         log_error("avrcp_browsing_controller_register_packet_handler called with NULL callback");
613         return;
614     }
615     avrcp_controller_context.browsing_avrcp_callback = callback;
616 }
617 
618 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){
619     return avrcp_browsing_connect(bd_addr, &avrcp_controller_context, ertm_buffer, size, ertm_config, avrcp_browsing_cid);
620 }
621 
622 uint8_t avrcp_browsing_controller_disconnect(uint16_t avrcp_browsing_cid){
623     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
624     if (!avrcp_connection){
625         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
626         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
627     }
628     if (avrcp_connection->browsing_connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
629 
630     l2cap_disconnect(avrcp_connection->browsing_connection->l2cap_browsing_cid, 0);
631     return ERROR_CODE_SUCCESS;
632 }
633 
634 uint8_t avrcp_avrcp_browsing_configure_incoming_connection(uint16_t avrcp_browsing_cid, uint8_t * ertm_buffer, uint32_t size, l2cap_ertm_config_t * ertm_config){
635     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
636     if (!avrcp_connection){
637         log_error("avrcp_avrcp_browsing_decline_incoming_connection: could not find a connection.");
638         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
639     }
640     if (!avrcp_connection->browsing_connection){
641         log_error("avrcp_avrcp_browsing_decline_incoming_connection: no browsing connection.");
642         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
643     }
644 
645     if (avrcp_connection->browsing_connection->state != AVCTP_CONNECTION_W4_ERTM_CONFIGURATION){
646         log_error("avrcp_avrcp_browsing_decline_incoming_connection: browsing connection in a wrong state.");
647         return ERROR_CODE_COMMAND_DISALLOWED;
648     }
649 
650     avrcp_connection->browsing_connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
651     avrcp_connection->browsing_connection->ertm_buffer = ertm_buffer;
652     avrcp_connection->browsing_connection->ertm_buffer_size = size;
653     memcpy(&avrcp_connection->browsing_connection->ertm_config, ertm_config, sizeof(l2cap_ertm_config_t));
654     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);
655     return ERROR_CODE_SUCCESS;
656 }
657 
658 uint8_t avrcp_avrcp_browsing_decline_incoming_connection(uint16_t avrcp_browsing_cid){
659     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
660     if (!avrcp_connection){
661         log_error("avrcp_avrcp_browsing_decline_incoming_connection: could not find a connection.");
662         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
663     }
664     if (!avrcp_connection->browsing_connection) return ERROR_CODE_SUCCESS;
665     if (avrcp_connection->browsing_connection->state > AVCTP_CONNECTION_W4_ERTM_CONFIGURATION) return ERROR_CODE_COMMAND_DISALLOWED;
666 
667     l2cap_decline_connection(avrcp_connection->browsing_connection->l2cap_browsing_cid);
668     // free connection
669     btstack_memory_avrcp_browsing_connection_free(avrcp_connection->browsing_connection);
670     avrcp_connection->browsing_connection = NULL;
671     return ERROR_CODE_SUCCESS;
672 }
673 
674 /**
675  * @brief Retrieve a listing of the contents of a folder.
676  * @param scope    0-player list, 1-virtual file system, 2-search, 3-now playing
677  * @param start_item
678  * @param end_item
679  * @param attribute_count
680  * @param attribute_list
681  **/
682 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){
683     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
684     if (!avrcp_connection){
685         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
686         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
687     }
688     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
689     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
690 
691     connection->get_folder_item = 1;
692     connection->scope = scope;
693     connection->start_item = start_item;
694     connection->end_item = end_item;
695     connection->attr_bitmap = attr_bitmap;
696 
697     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
698     return ERROR_CODE_SUCCESS;
699 }
700 
701 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){
702     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_MEDIA_PLAYER_LIST, start_item, end_item, attr_bitmap);
703 }
704 
705 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){
706     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 1, 0, 0xFFFFFFFF, attr_bitmap);
707     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_MEDIA_PLAYER_VIRTUAL_FILESYSTEM, start_item, end_item, attr_bitmap);
708 }
709 
710 uint8_t avrcp_browsing_controller_browse_media(uint16_t avrcp_browsing_cid, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
711     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 2, 0, 0xFFFFFFFF, 0, NULL);
712     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_SEARCH, start_item, end_item, attr_bitmap);
713 }
714 
715 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){
716     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_NOW_PLAYING, start_item, end_item, attr_bitmap);
717 }
718 
719 
720 uint8_t avrcp_browsing_controller_set_browsed_player(uint16_t avrcp_browsing_cid, uint16_t browsed_player_id){
721     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
722     if (!avrcp_connection){
723         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
724         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
725     }
726 
727     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
728     if (connection->state != AVCTP_CONNECTION_OPENED){
729         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
730         return ERROR_CODE_COMMAND_DISALLOWED;
731     }
732 
733     connection->set_browsed_player_id = 1;
734     connection->browsed_player_id = browsed_player_id;
735     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
736     return ERROR_CODE_SUCCESS;
737 }
738 
739 uint8_t avrcp_browsing_controller_set_addressed_player(uint16_t avrcp_browsing_cid, uint16_t addressed_player_id){
740     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
741     if (!avrcp_connection){
742         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
743         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
744     }
745 
746     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
747     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
748         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
749         return ERROR_CODE_COMMAND_DISALLOWED;
750     }
751 
752     connection->set_addressed_player_id = 1;
753     connection->addressed_player_id = addressed_player_id;
754     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
755     return ERROR_CODE_SUCCESS;
756 }
757 
758 /**
759  * @brief Retrieve a listing of the contents of a folder.
760  * @param direction     0-folder up, 1-folder down
761  * @param folder_uid    8 bytes long
762  **/
763 uint8_t avrcp_browsing_controller_change_path(uint16_t avrcp_browsing_cid, uint8_t direction, uint8_t * folder_uid){
764     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
765     if (!avrcp_connection){
766         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
767         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
768     }
769 
770     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
771 
772     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
773         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
774         return ERROR_CODE_COMMAND_DISALLOWED;
775     }
776 
777     if (!connection->browsed_player_id){
778         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
779         return ERROR_CODE_COMMAND_DISALLOWED;
780     }
781     printf(" send change path\n");
782     connection->change_path = 1;
783     connection->direction = direction;
784     memset(connection->folder_uid, 0, 8);
785     if (folder_uid){
786         memcpy(connection->folder_uid, folder_uid, 8);
787     }
788 
789     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
790     return ERROR_CODE_SUCCESS;
791 }
792 
793 uint8_t avrcp_browsing_controller_go_up_one_level(uint16_t avrcp_browsing_cid){
794     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 0, NULL);
795 }
796 
797 uint8_t avrcp_browsing_controller_go_down_one_level(uint16_t avrcp_browsing_cid, uint8_t * folder_uid){
798     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 1, folder_uid);
799 }
800 
801 uint8_t avrcp_browsing_controller_search(uint16_t avrcp_browsing_cid, uint16_t search_str_len, char * search_str){
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_change_path: could not find a connection.");
805         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
806     }
807 
808     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
809 
810     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
811         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
812         return ERROR_CODE_COMMAND_DISALLOWED;
813     }
814 
815     if (!connection->browsed_player_id){
816         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
817         return ERROR_CODE_COMMAND_DISALLOWED;
818     }
819     if (!search_str || search_str_len == 0){
820         return AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND;
821     }
822 
823     connection->search = 1;
824 
825     connection->search_str_len = btstack_min(search_str_len, sizeof(connection->search_str)-1);
826     memset(connection->search_str, 0, sizeof(connection->search_str));
827     memcpy(connection->search_str, search_str, connection->search_str_len);
828     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
829     return ERROR_CODE_SUCCESS;
830 }