xref: /btstack/src/classic/avrcp_browsing_controller.c (revision 9bb24eb5f0e1bb149d5b92daba17ced5b5a8a890)
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     pos += 2;
314     command[pos++] = connection->direction;
315     memcpy(command+pos, connection->folder_uid, 8);
316     pos += 8;
317     return l2cap_send(cid, command, pos);
318 }
319 
320 static int avrcp_browsing_controller_send_search_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
321     uint8_t command[100];
322     int pos = 0;
323     // transport header
324     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
325     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
326     // Profile IDentifier (PID)
327     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
328     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
329     command[pos++] = AVRCP_PDU_ID_SEARCH;
330 
331     big_endian_store_16(command, pos, 4 + connection->search_str_len);
332     pos += 2;
333 
334     big_endian_store_16(command, pos, 0x006A);
335     pos += 2;
336     big_endian_store_16(command, pos, connection->search_str_len);
337     pos += 2;
338 
339     memcpy(command+pos,connection->search_str, connection->search_str_len);
340     pos += connection->search_str_len;
341     return l2cap_send(cid, command, pos);
342 }
343 
344 static int avrcp_browsing_controller_send_set_browsed_player_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
345     uint8_t command[100];
346     int pos = 0;
347     // transport header
348     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
349     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
350     // Profile IDentifier (PID)
351     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
352     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
353     command[pos++] = AVRCP_PDU_ID_SET_BROWSED_PLAYER;
354 
355     big_endian_store_16(command, pos, 2);
356     pos += 2;
357     big_endian_store_16(command, pos, connection->browsed_player_id);
358     pos += 2;
359     return l2cap_send(cid, command, pos);
360 }
361 
362 static int avrcp_browsing_controller_send_get_total_nr_items_cmd(uint16_t cid, avrcp_browsing_connection_t * connection){
363     uint8_t command[7];
364     int pos = 0;
365     // transport header
366     // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
367     command[pos++] = (connection->transaction_label << 4) | (AVRCP_SINGLE_PACKET << 2) | (AVRCP_COMMAND_FRAME << 1) | 0;
368     // Profile IDentifier (PID)
369     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL >> 8;
370     command[pos++] = BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL & 0x00FF;
371     command[pos++] = AVRCP_PDU_ID_GET_TOTAL_NUMBER_OF_ITEMS;
372 
373     big_endian_store_16(command, pos, 1);
374     pos += 2;
375     command[pos++] = connection->get_total_nr_items_scope;
376     return l2cap_send(cid, command, pos);
377 }
378 
379 static void avrcp_browsing_controller_handle_can_send_now(avrcp_browsing_connection_t * connection){
380     switch (connection->state){
381         case AVCTP_CONNECTION_OPENED:
382             if (connection->set_browsed_player_id){
383                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
384                 connection->set_browsed_player_id = 0;
385                 avrcp_browsing_controller_send_set_browsed_player_cmd(connection->l2cap_browsing_cid, connection);
386                 break;
387             }
388 
389             if (connection->get_total_nr_items){
390                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
391                 connection->get_total_nr_items = 0;
392                 avrcp_browsing_controller_send_get_total_nr_items_cmd(connection->l2cap_browsing_cid, connection);
393                 break;
394             }
395 
396             if (connection->get_folder_item){
397                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
398                 connection->get_folder_item = 0;
399                 avrcp_browsing_controller_send_get_folder_items_cmd(connection->l2cap_browsing_cid, connection);
400                 break;
401             }
402             if (connection->change_path){
403                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
404                 connection->change_path = 0;
405                 avrcp_browsing_controller_send_change_path_cmd(connection->l2cap_browsing_cid, connection);
406                 break;
407             }
408             if (connection->search){
409                 connection->state = AVCTP_W2_RECEIVE_RESPONSE;
410                 connection->search = 0;
411                 avrcp_browsing_controller_send_search_cmd(connection->l2cap_browsing_cid, connection);
412                 break;
413             }
414             break;
415         default:
416             return;
417     }
418 }
419 
420 
421 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){
422     if (!callback) return;
423     uint8_t event[9];
424     int pos = 0;
425     event[pos++] = HCI_EVENT_AVRCP_META;
426     event[pos++] = sizeof(event) - 2;
427     event[pos++] = AVRCP_SUBEVENT_BROWSING_DONE;
428     little_endian_store_16(event, pos, browsing_cid);
429     pos += 2;
430     little_endian_store_16(event, pos, uid_counter);
431     pos += 2;
432     event[pos++] = browsing_status;
433     event[pos++] = bluetooth_status;
434     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
435 }
436 
437 static void avrcp_parser_reset(avrcp_browsing_connection_t * connection){
438     connection->parser_attribute_header_pos = 0;
439     connection->parsed_attribute_value_offset = 0;
440     connection->parsed_num_attributes = 0;
441     connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
442 }
443 
444 
445 static void avrcp_browsing_parser_process_byte(uint8_t byte, avrcp_browsing_connection_t * connection){
446     uint8_t prepended_header_size = 1;
447     switch(connection->parser_state){
448         case AVRCP_PARSER_GET_ATTRIBUTE_HEADER:{
449             connection->parser_attribute_header[connection->parser_attribute_header_pos++] = byte;
450             if (connection->parser_attribute_header_pos < AVRCP_BROWSING_ITEM_HEADER_LEN) break;
451 
452             uint16_t attribute_total_value_len = big_endian_read_16(connection->parser_attribute_header, 1);
453             connection->parsed_attribute_value[connection->parsed_attribute_value_offset++] = connection->parser_attribute_header[0];   // prepend with item type
454             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
455             connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_VALUE;
456             break;
457         }
458         case AVRCP_PARSER_GET_ATTRIBUTE_VALUE:{
459             if (connection->parsed_attribute_value_offset < connection->parsed_attribute_value_len + prepended_header_size){
460                 connection->parsed_attribute_value[connection->parsed_attribute_value_offset++] = byte;
461                 break;
462             }
463             if (connection->parsed_attribute_value_offset < big_endian_read_16(connection->parser_attribute_header, 1)){
464                 connection->parser_state = AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE;
465                 break;
466             }
467 
468             connection->parsed_num_attributes++;
469             (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, connection->l2cap_browsing_cid, &connection->parsed_attribute_value[0], connection->parsed_attribute_value_offset);
470 
471             if (connection->parsed_num_attributes == connection->num_items){
472                 avrcp_parser_reset(connection);
473                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
474                 connection->parser_attribute_header_pos = 0;
475                 break;
476             }
477             break;
478         }
479         case AVRCP_PARSER_IGNORE_REST_OF_ATTRIBUTE_VALUE:
480             if (connection->parsed_attribute_value_offset < big_endian_read_16(connection->parser_attribute_header, 1) + prepended_header_size){
481                 connection->parsed_attribute_value_offset++;
482                 break;
483             }
484             connection->parsed_num_attributes++;
485             (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, connection->l2cap_browsing_cid, &connection->parsed_attribute_value[0], connection->parsed_attribute_value_offset);
486 
487             if (connection->parsed_num_attributes == connection->num_items){
488                 avrcp_parser_reset(connection);
489                 connection->parser_state = AVRCP_PARSER_GET_ATTRIBUTE_HEADER;
490                 connection->parser_attribute_header_pos = 0;
491                 break;
492             }
493             break;
494         default:
495             break;
496     }
497 }
498 
499 static void avrcp_browsing_parse_and_emit_element_attrs(uint8_t * packet, uint16_t num_bytes_to_read, avrcp_browsing_connection_t * connection){
500     int i;
501     for (i=0;i<num_bytes_to_read;i++){
502         avrcp_browsing_parser_process_byte(packet[i], connection);
503     }
504 }
505 
506 static void avrcp_browsing_controller_emit_done(btstack_packet_handler_t callback, uint16_t browsing_cid, uint8_t browsing_status, uint8_t bluetooth_status){
507     avrcp_browsing_controller_emit_done_with_uid_counter(callback, browsing_cid, 0, browsing_status, bluetooth_status);
508 }
509 
510 
511 static void avrcp_browsing_controller_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
512     avrcp_browsing_connection_t * browsing_connection;
513 
514     switch (packet_type) {
515         case L2CAP_DATA_PACKET:{
516             browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
517             if (!browsing_connection) break;
518             int pos = 0;
519             uint8_t transport_header = packet[pos++];
520             // Transaction label | Packet_type | C/R | IPID (1 == invalid profile identifier)
521             // uint8_t transaction_label = transport_header >> 4;
522             avrcp_packet_type_t avctp_packet_type = (transport_header & 0x0F) >> 2;
523             // printf("L2CAP_DATA_PACKET, packet type \n");
524             switch (avctp_packet_type){
525                 case AVRCP_SINGLE_PACKET:
526                 case AVRCP_START_PACKET:
527                     // uint8_t frame_type = (transport_header & 0x03) >> 1;
528                     // uint8_t ipid = transport_header & 0x01;
529                     pos += 2;
530                     browsing_connection->num_packets = 1;
531                     if (avctp_packet_type == AVRCP_START_PACKET){
532                         browsing_connection->num_packets = packet[pos++];
533                     }
534                     if (pos + 4 > size){
535                         avrcp_browsing_controller_emit_done(avrcp_controller_context.browsing_avrcp_callback, channel, AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND, ERROR_CODE_SUCCESS);
536                         return;
537                     }
538                     browsing_connection->pdu_id = packet[pos++];
539                     // uint16_t length = big_endian_read_16(packet, pos);
540                     pos += 2;
541                     browsing_connection->browsing_status = packet[pos++];
542                     if (browsing_connection->browsing_status != AVRCP_BROWSING_ERROR_CODE_SUCCESS){
543                         avrcp_browsing_controller_emit_done(avrcp_controller_context.browsing_avrcp_callback, channel, browsing_connection->browsing_status, ERROR_CODE_SUCCESS);
544                         return;
545                     }
546                     browsing_connection->uid_counter =  big_endian_read_16(packet, pos);
547                     pos += 2;
548                     break;
549                 default:
550                     break;
551             }
552 
553             uint32_t i;
554             switch(browsing_connection->pdu_id){
555                 case AVRCP_PDU_ID_CHANGE_PATH:
556                     printf("AVRCP_PDU_ID_CHANGE_PATH \n");
557                     break;
558                 case AVRCP_PDU_ID_SET_ADDRESSED_PLAYER:
559                     printf("AVRCP_PDU_ID_SET_ADDRESSED_PLAYER \n");
560                     break;
561                 case AVRCP_PDU_ID_GET_TOTAL_NUMBER_OF_ITEMS:{
562                     uint32_t num_items = big_endian_read_32(packet, pos);
563                     pos += 4;
564                     printf("TDO: send event, uid_counter %d, num_items %d\n", browsing_connection->uid_counter, num_items);
565                     break;
566                 }
567                 case AVRCP_PDU_ID_SET_BROWSED_PLAYER:{
568                     // uint32_t num_items = big_endian_read_32(packet, pos);
569                     pos += 4;
570                     // uint16_t charset = big_endian_read_16(packet, pos);
571                     pos += 2;
572                     uint8_t folder_depth = packet[pos++];
573 
574                     for (i = 0; i < folder_depth; i++){
575                         uint16_t folder_name_length = big_endian_read_16(packet, pos);
576                         pos += 2;
577                         // reuse packet and add data type as a header
578                         packet[pos-1] = AVRCP_BROWSING_MEDIA_ROOT_FOLDER;
579                         (*avrcp_controller_context.browsing_avrcp_callback)(AVRCP_BROWSING_DATA_PACKET, channel, packet+pos-1, folder_name_length+1);
580                         pos += folder_name_length;
581                     }
582                     break;
583                 }
584 
585                 case AVRCP_PDU_ID_GET_FOLDER_ITEMS:{
586                     printf("AVRCP_PDU_ID_GET_FOLDER_ITEMS\n");
587                     switch (avctp_packet_type){
588                         case AVRCP_SINGLE_PACKET:
589                         case AVRCP_START_PACKET:
590                             avrcp_parser_reset(browsing_connection);
591                             browsing_connection->num_items = big_endian_read_16(packet, pos); //num_items
592                             pos += 2;
593                             printf(" num items %d\n", browsing_connection->num_items);
594                             avrcp_browsing_parse_and_emit_element_attrs(packet+pos, size-pos, browsing_connection);
595                             break;
596 
597                         case AVRCP_CONTINUE_PACKET:
598                             avrcp_browsing_parse_and_emit_element_attrs(packet+pos, size-pos, browsing_connection);
599                             break;
600 
601                         case AVRCP_END_PACKET:
602                             avrcp_browsing_parse_and_emit_element_attrs(packet+pos, size-pos, browsing_connection);
603                             avrcp_parser_reset(browsing_connection);
604                             break;
605                     }
606                     break;
607                 }
608 
609                 case AVRCP_PDU_ID_SEARCH:{
610                         uint32_t num_items = big_endian_read_32(packet, pos);
611                         printf("TODO: send as event, search found %d items\n", num_items);
612                         break;
613                     }
614                 default:
615                     break;
616             }
617 
618             switch (avctp_packet_type){
619                 case AVRCP_SINGLE_PACKET:
620                 case AVRCP_END_PACKET:
621                     browsing_connection->state = AVCTP_CONNECTION_OPENED;
622                     avrcp_browsing_controller_emit_done(avrcp_controller_context.browsing_avrcp_callback, channel, browsing_connection->browsing_status, ERROR_CODE_SUCCESS);
623                     break;
624                 default:
625                     break;
626             }
627             break;
628         }
629         case HCI_EVENT_PACKET:
630             switch (hci_event_packet_get_type(packet)){
631                 case L2CAP_EVENT_CAN_SEND_NOW:
632                     browsing_connection = get_avrcp_browsing_connection_for_l2cap_cid(channel, &avrcp_controller_context);
633                     if (!browsing_connection) break;
634                     avrcp_browsing_controller_handle_can_send_now(browsing_connection);
635                     break;
636             default:
637                 avrcp_browser_packet_handler(packet_type, channel, packet, size, &avrcp_controller_context);
638                 break;
639         }
640         default:
641             break;
642     }
643 }
644 
645 void avrcp_browsing_controller_init(void){
646     avrcp_controller_context.browsing_packet_handler = avrcp_browsing_controller_packet_handler;
647     l2cap_register_service(&avrcp_browsing_controller_packet_handler, PSM_AVCTP_BROWSING, 0xffff, LEVEL_0);
648 }
649 
650 void avrcp_browsing_controller_register_packet_handler(btstack_packet_handler_t callback){
651     if (callback == NULL){
652         log_error("avrcp_browsing_controller_register_packet_handler called with NULL callback");
653         return;
654     }
655     avrcp_controller_context.browsing_avrcp_callback = callback;
656 }
657 
658 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){
659     return avrcp_browsing_connect(bd_addr, &avrcp_controller_context, ertm_buffer, size, ertm_config, avrcp_browsing_cid);
660 }
661 
662 uint8_t avrcp_browsing_controller_disconnect(uint16_t avrcp_browsing_cid){
663     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
664     if (!avrcp_connection){
665         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
666         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
667     }
668     if (avrcp_connection->browsing_connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
669 
670     l2cap_disconnect(avrcp_connection->browsing_connection->l2cap_browsing_cid, 0);
671     return ERROR_CODE_SUCCESS;
672 }
673 
674 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){
675     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
676     if (!avrcp_connection){
677         log_error("avrcp_avrcp_browsing_decline_incoming_connection: could not find a connection.");
678         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
679     }
680     if (!avrcp_connection->browsing_connection){
681         log_error("avrcp_avrcp_browsing_decline_incoming_connection: no browsing connection.");
682         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
683     }
684 
685     if (avrcp_connection->browsing_connection->state != AVCTP_CONNECTION_W4_ERTM_CONFIGURATION){
686         log_error("avrcp_avrcp_browsing_decline_incoming_connection: browsing connection in a wrong state.");
687         return ERROR_CODE_COMMAND_DISALLOWED;
688     }
689 
690     avrcp_connection->browsing_connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
691     avrcp_connection->browsing_connection->ertm_buffer = ertm_buffer;
692     avrcp_connection->browsing_connection->ertm_buffer_size = size;
693     memcpy(&avrcp_connection->browsing_connection->ertm_config, ertm_config, sizeof(l2cap_ertm_config_t));
694     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);
695     return ERROR_CODE_SUCCESS;
696 }
697 
698 uint8_t avrcp_avrcp_browsing_decline_incoming_connection(uint16_t avrcp_browsing_cid){
699     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
700     if (!avrcp_connection){
701         log_error("avrcp_avrcp_browsing_decline_incoming_connection: could not find a connection.");
702         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
703     }
704     if (!avrcp_connection->browsing_connection) return ERROR_CODE_SUCCESS;
705     if (avrcp_connection->browsing_connection->state > AVCTP_CONNECTION_W4_ERTM_CONFIGURATION) return ERROR_CODE_COMMAND_DISALLOWED;
706 
707     l2cap_decline_connection(avrcp_connection->browsing_connection->l2cap_browsing_cid);
708     // free connection
709     btstack_memory_avrcp_browsing_connection_free(avrcp_connection->browsing_connection);
710     avrcp_connection->browsing_connection = NULL;
711     return ERROR_CODE_SUCCESS;
712 }
713 
714 /**
715  * @brief Retrieve a listing of the contents of a folder.
716  * @param scope    0-player list, 1-virtual file system, 2-search, 3-now playing
717  * @param start_item
718  * @param end_item
719  * @param attribute_count
720  * @param attribute_list
721  **/
722 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){
723     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
724     if (!avrcp_connection){
725         log_error("avrcp_browsing_controller_disconnect: could not find a connection.");
726         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
727     }
728     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
729     if (connection->state != AVCTP_CONNECTION_OPENED) return ERROR_CODE_COMMAND_DISALLOWED;
730 
731     connection->get_folder_item = 1;
732     connection->scope = scope;
733     connection->start_item = start_item;
734     connection->end_item = end_item;
735     connection->attr_bitmap = attr_bitmap;
736 
737     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
738     return ERROR_CODE_SUCCESS;
739 }
740 
741 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){
742     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_MEDIA_PLAYER_LIST, start_item, end_item, attr_bitmap);
743 }
744 
745 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){
746     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 1, 0, 0xFFFFFFFF, attr_bitmap);
747     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_MEDIA_PLAYER_VIRTUAL_FILESYSTEM, start_item, end_item, attr_bitmap);
748 }
749 
750 uint8_t avrcp_browsing_controller_browse_media(uint16_t avrcp_browsing_cid, uint32_t start_item, uint32_t end_item, uint32_t attr_bitmap){
751     // return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, 2, 0, 0xFFFFFFFF, 0, NULL);
752     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_SEARCH, start_item, end_item, attr_bitmap);
753 }
754 
755 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){
756     return avrcp_browsing_controller_get_folder_items(avrcp_browsing_cid, AVRCP_BROWSING_NOW_PLAYING, start_item, end_item, attr_bitmap);
757 }
758 
759 
760 uint8_t avrcp_browsing_controller_set_browsed_player(uint16_t avrcp_browsing_cid, uint16_t browsed_player_id){
761     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
762     if (!avrcp_connection){
763         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
764         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
765     }
766 
767     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
768     if (connection->state != AVCTP_CONNECTION_OPENED){
769         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
770         return ERROR_CODE_COMMAND_DISALLOWED;
771     }
772 
773     connection->set_browsed_player_id = 1;
774     connection->browsed_player_id = browsed_player_id;
775     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
776     return ERROR_CODE_SUCCESS;
777 }
778 
779 /**
780  * @brief Retrieve a listing of the contents of a folder.
781  * @param direction     0-folder up, 1-folder down
782  * @param folder_uid    8 bytes long
783  **/
784 uint8_t avrcp_browsing_controller_change_path(uint16_t avrcp_browsing_cid, uint8_t direction, uint8_t * folder_uid){
785     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
786     if (!avrcp_connection){
787         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
788         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
789     }
790 
791     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
792 
793     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
794         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
795         return ERROR_CODE_COMMAND_DISALLOWED;
796     }
797 
798     if (!connection->browsed_player_id){
799         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
800         return ERROR_CODE_COMMAND_DISALLOWED;
801     }
802     printf(" send change path\n");
803     connection->change_path = 1;
804     connection->direction = direction;
805     memset(connection->folder_uid, 0, 8);
806     if (folder_uid){
807         memcpy(connection->folder_uid, folder_uid, 8);
808     }
809 
810     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
811     return ERROR_CODE_SUCCESS;
812 }
813 
814 uint8_t avrcp_browsing_controller_go_up_one_level(uint16_t avrcp_browsing_cid){
815     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 0, NULL);
816 }
817 
818 uint8_t avrcp_browsing_controller_go_down_one_level(uint16_t avrcp_browsing_cid, uint8_t * folder_uid){
819     return avrcp_browsing_controller_change_path(avrcp_browsing_cid, 1, folder_uid);
820 }
821 
822 uint8_t avrcp_browsing_controller_search(uint16_t avrcp_browsing_cid, uint16_t search_str_len, char * search_str){
823     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
824     if (!avrcp_connection){
825         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
826         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
827     }
828 
829     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
830 
831     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
832         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
833         return ERROR_CODE_COMMAND_DISALLOWED;
834     }
835 
836     if (!connection->browsed_player_id){
837         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
838         return ERROR_CODE_COMMAND_DISALLOWED;
839     }
840     if (!search_str || search_str_len == 0){
841         return AVRCP_BROWSING_ERROR_CODE_INVALID_COMMAND;
842     }
843 
844     connection->search = 1;
845 
846     connection->search_str_len = btstack_min(search_str_len, sizeof(connection->search_str)-1);
847     memset(connection->search_str, 0, sizeof(connection->search_str));
848     memcpy(connection->search_str, search_str, connection->search_str_len);
849     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
850     return ERROR_CODE_SUCCESS;
851 }
852 
853 uint8_t avrcp_browsing_controller_get_total_nr_items(uint16_t avrcp_browsing_cid, avrcp_browsing_scope_t scope){
854     avrcp_connection_t * avrcp_connection = get_avrcp_connection_for_browsing_cid(avrcp_browsing_cid, &avrcp_controller_context);
855     if (!avrcp_connection){
856         log_error("avrcp_browsing_controller_change_path: could not find a connection.");
857         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
858     }
859 
860     avrcp_browsing_connection_t * connection = avrcp_connection->browsing_connection;
861 
862     if (!connection || connection->state != AVCTP_CONNECTION_OPENED){
863         log_error("avrcp_browsing_controller_change_path: connection in wrong state.");
864         return ERROR_CODE_COMMAND_DISALLOWED;
865     }
866 
867     if (!connection->browsed_player_id){
868         log_error("avrcp_browsing_controller_change_path: no browsed player set.");
869         return ERROR_CODE_COMMAND_DISALLOWED;
870     }
871     connection->get_total_nr_items = 1;
872     connection->get_total_nr_items_scope = scope;
873     avrcp_request_can_send_now(avrcp_connection, connection->l2cap_browsing_cid);
874     return ERROR_CODE_SUCCESS;
875 }