xref: /btstack/src/classic/avrcp.c (revision 3a19cf32d7785aa01975a91531f8618cf4de7446)
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 BLUEKITCHEN
24  * GMBH 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.c"
39 
40 #include <stdint.h>
41 #include <string.h>
42 // snprintf
43 #include <stdio.h>
44 
45 #include "bluetooth_psm.h"
46 #include "bluetooth_sdp.h"
47 #include "btstack_debug.h"
48 #include "btstack_event.h"
49 #include "btstack_memory.h"
50 #include "classic/sdp_client.h"
51 #include "classic/sdp_util.h"
52 #include "classic/avrcp.h"
53 
54 
55 typedef struct {
56     uint8_t  parse_sdp_record;
57     uint32_t record_id;
58     uint16_t avrcp_cid;
59     uint16_t avrcp_l2cap_psm;
60     uint16_t avrcp_version;
61 
62     uint16_t browsing_l2cap_psm;
63     uint16_t browsing_version;
64 } avrcp_sdp_query_context_t;
65 
66 static void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
67 
68 static const char * avrcp_default_controller_service_name = "BTstack AVRCP Controller Service";
69 static const char * avrcp_default_controller_service_provider_name = "BTstack AVRCP Controller Service Provider";
70 static const char * avrcp_defaul_target_service_name = "BTstack AVRCP Target Service";
71 static const char * avrcp_default_target_service_provider_name = "BTstack AVRCP Target Service Provider";
72 
73 static const char * avrcp_subunit_type_name[] = {
74         "MONITOR", "AUDIO", "PRINTER", "DISC", "TAPE_RECORDER_PLAYER", "TUNER",
75         "CA", "CAMERA", "RESERVED", "PANEL", "BULLETIN_BOARD", "CAMERA_STORAGE",
76         "VENDOR_UNIQUE", "RESERVED_FOR_ALL_SUBUNIT_TYPES",
77         "EXTENDED_TO_NEXT_BYTE", "UNIT", "ERROR"
78 };
79 
80 // default subunit info: single PANEL subunit
81 static const uint8_t avrcp_default_subunit_info[] = { AVRCP_SUBUNIT_TYPE_PANEL << 3};
82 
83 // globals
84 static bool avrcp_l2cap_service_registered = false;
85 
86 // connections
87 static uint16_t                 avrcp_cid_counter;
88 static btstack_linked_list_t    avrcp_connections;
89 
90 // higher layer callbacks
91 static btstack_packet_handler_t avrcp_callback;
92 static btstack_packet_handler_t avrcp_controller_packet_handler;
93 static btstack_packet_handler_t avrcp_target_packet_handler;
94 
95 // sdp query
96 static btstack_context_callback_registration_t avrcp_sdp_query_registration;
97 static avrcp_sdp_query_context_t               avrcp_sdp_query_context;
98 static uint8_t                                 avrcp_sdp_query_attribute_value[45];
99 static const unsigned int                      avrcp_sdp_query_attribute_value_buffer_size = sizeof(avrcp_sdp_query_attribute_value);
100 
101 
102 const char * avrcp_subunit2str(uint16_t index){
103     if (index <= 11) return avrcp_subunit_type_name[index];
104     if ((index >= 0x1C) && (index <= 0x1F)) return avrcp_subunit_type_name[index - 0x10];
105     return avrcp_subunit_type_name[16];
106 }
107 
108 static const char * avrcp_event_name[] = {
109     "ERROR", "PLAYBACK_STATUS_CHANGED",
110     "TRACK_CHANGED", "TRACK_REACHED_END", "TRACK_REACHED_START",
111     "PLAYBACK_POS_CHANGED", "BATT_STATUS_CHANGED", "SYSTEM_STATUS_CHANGED",
112     "PLAYER_APPLICATION_SETTING_CHANGED", "NOW_PLAYING_CONTENT_CHANGED",
113     "AVAILABLE_PLAYERS_CHANGED", "ADDRESSED_PLAYER_CHANGED", "UIDS_CHANGED", "VOLUME_CHANGED"
114 };
115 const char * avrcp_event2str(uint16_t index){
116     if (index <= 0x0d) return avrcp_event_name[index];
117     return avrcp_event_name[0];
118 }
119 
120 static const char * avrcp_operation_name[] = {
121     "SKIP", NULL, NULL, NULL, NULL,
122     "VOLUME_UP", "VOLUME_DOWN", "MUTE", "PLAY", "STOP", "PAUSE", NULL,
123     "REWIND", "FAST_FORWARD", NULL, "FORWARD", "BACKWARD" // 0x4C
124 };
125 
126 const char * avrcp_operation2str(uint8_t operation_id){
127     char * name = NULL;
128     if ((operation_id >= AVRCP_OPERATION_ID_SKIP) && (operation_id <= AVRCP_OPERATION_ID_BACKWARD)){
129         name = (char *)avrcp_operation_name[operation_id - AVRCP_OPERATION_ID_SKIP];
130     }
131     if (name == NULL){
132         static char buffer[13];
133         snprintf(buffer, sizeof(buffer), "Unknown 0x%02x", operation_id);
134         buffer[sizeof(buffer)-1] = 0;
135         return buffer;
136     } else {
137         return name;
138     }
139 }
140 
141 static const char * avrcp_media_attribute_id_name[] = {
142     "NONE", "TITLE", "ARTIST", "ALBUM", "TRACK", "TOTAL TRACKS", "GENRE", "SONG LENGTH"
143 };
144 const char * avrcp_attribute2str(uint8_t index){
145     if ((index >= 1) && (index <= 7)) return avrcp_media_attribute_id_name[index];
146     return avrcp_media_attribute_id_name[0];
147 }
148 
149 static const char * avrcp_play_status_name[] = {
150     "STOPPED", "PLAYING", "PAUSED", "FORWARD SEEK", "REVERSE SEEK",
151     "ERROR" // 0xFF
152 };
153 const char * avrcp_play_status2str(uint8_t index){
154     if ((index >= 1) && (index <= 4)) return avrcp_play_status_name[index];
155     return avrcp_play_status_name[5];
156 }
157 
158 static const char * avrcp_ctype_name[] = {
159     "CONTROL",
160     "STATUS",
161     "SPECIFIC_INQUIRY",
162     "NOTIFY",
163     "GENERAL_INQUIRY",
164     "RESERVED5",
165     "RESERVED6",
166     "RESERVED7",
167     "NOT IMPLEMENTED IN REMOTE",
168     "ACCEPTED BY REMOTE",
169     "REJECTED BY REMOTE",
170     "IN_TRANSITION",
171     "IMPLEMENTED_STABLE",
172     "CHANGED_STABLE",
173     "RESERVED",
174     "INTERIM"
175 };
176 const char * avrcp_ctype2str(uint8_t index){
177     if (index < sizeof(avrcp_ctype_name)){
178         return avrcp_ctype_name[index];
179     }
180     return "NONE";
181 }
182 
183 static const char * avrcp_shuffle_mode_name[] = {
184     "SHUFFLE OFF",
185     "SHUFFLE ALL TRACKS",
186     "SHUFFLE GROUP"
187 };
188 
189 const char * avrcp_shuffle2str(uint8_t index){
190     if ((index >= 1) && (index <= 3)) return avrcp_shuffle_mode_name[index-1];
191     return "NONE";
192 }
193 
194 static const char * avrcp_repeat_mode_name[] = {
195     "REPEAT OFF",
196     "REPEAT SINGLE TRACK",
197     "REPEAT ALL TRACKS",
198     "REPEAT GROUP"
199 };
200 
201 const char * avrcp_repeat2str(uint8_t index){
202     if ((index >= 1) && (index <= 4)) return avrcp_repeat_mode_name[index-1];
203     return "NONE";
204 }
205 
206 btstack_linked_list_t avrcp_get_connections(void){
207     return avrcp_connections;
208 }
209 
210 uint8_t avrcp_cmd_opcode(uint8_t *packet, uint16_t size){
211     uint8_t cmd_opcode_index = 5;
212     if (cmd_opcode_index > size) return AVRCP_CMD_OPCODE_UNDEFINED;
213     return packet[cmd_opcode_index];
214 }
215 
216 void avrcp_create_sdp_record(uint8_t controller, uint8_t * service, uint32_t service_record_handle, uint8_t browsing, uint16_t supported_features,
217     const char * service_name, const char * service_provider_name){
218     uint8_t* attribute;
219     de_create_sequence(service);
220 
221     // 0x0000 "Service Record Handle"
222     de_add_number(service, DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_RECORD_HANDLE);
223     de_add_number(service, DE_UINT, DE_SIZE_32, service_record_handle);
224 
225     // 0x0001 "Service Class ID List"
226     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST);
227     attribute = de_push_sequence(service);
228     {
229         if (controller){
230             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
231             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER);
232         } else {
233             de_add_number(attribute, DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET);
234         }
235     }
236     de_pop_sequence(service, attribute);
237 
238     // 0x0004 "Protocol Descriptor List"
239     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST);
240     attribute = de_push_sequence(service);
241     {
242         uint8_t* l2cpProtocol = de_push_sequence(attribute);
243         {
244             de_add_number(l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
245             de_add_number(l2cpProtocol,  DE_UINT, DE_SIZE_16, BLUETOOTH_PSM_AVCTP);
246         }
247         de_pop_sequence(attribute, l2cpProtocol);
248 
249         uint8_t* avctpProtocol = de_push_sequence(attribute);
250         {
251             de_add_number(avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // avctpProtocol_service
252             de_add_number(avctpProtocol,  DE_UINT, DE_SIZE_16,  0x0104);    // version
253         }
254         de_pop_sequence(attribute, avctpProtocol);
255     }
256     de_pop_sequence(service, attribute);
257 
258     // 0x0005 "Public Browse Group"
259     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BROWSE_GROUP_LIST); // public browse group
260     attribute = de_push_sequence(service);
261     {
262         de_add_number(attribute,  DE_UUID, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_PUBLIC_BROWSE_ROOT);
263     }
264     de_pop_sequence(service, attribute);
265 
266     // 0x0009 "Bluetooth Profile Descriptor List"
267     de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_BLUETOOTH_PROFILE_DESCRIPTOR_LIST);
268     attribute = de_push_sequence(service);
269     {
270         uint8_t *avrcProfile = de_push_sequence(attribute);
271         {
272             de_add_number(avrcProfile,  DE_UUID, DE_SIZE_16, BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL);
273             de_add_number(avrcProfile,  DE_UINT, DE_SIZE_16, 0x0106);
274         }
275         de_pop_sequence(attribute, avrcProfile);
276     }
277     de_pop_sequence(service, attribute);
278 
279     // 0x000d "Additional Bluetooth Profile Descriptor List"
280     if (browsing){
281         de_add_number(service,  DE_UINT, DE_SIZE_16, BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS);
282         attribute = de_push_sequence(service);
283         {
284             uint8_t * des = de_push_sequence(attribute);
285             {
286                 uint8_t* browsing_l2cpProtocol = de_push_sequence(des);
287                 {
288                     de_add_number(browsing_l2cpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_L2CAP);
289                     de_add_number(browsing_l2cpProtocol,  DE_UINT, DE_SIZE_16, BLUETOOTH_PSM_AVCTP_BROWSING);
290                 }
291                 de_pop_sequence(des, browsing_l2cpProtocol);
292 
293                 uint8_t* browsing_avctpProtocol = de_push_sequence(des);
294                 {
295                     de_add_number(browsing_avctpProtocol,  DE_UUID, DE_SIZE_16, BLUETOOTH_PROTOCOL_AVCTP);  // browsing_avctpProtocol_service
296                     de_add_number(browsing_avctpProtocol,  DE_UINT, DE_SIZE_16, 0x0104);                   // version
297                 }
298                 de_pop_sequence(des, browsing_avctpProtocol);
299             }
300             de_pop_sequence(attribute, des);
301         }
302         de_pop_sequence(service, attribute);
303     }
304 
305 
306     // 0x0100 "Service Name"
307     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0100);
308     if (service_name){
309         de_add_data(service,  DE_STRING, strlen(service_name), (uint8_t *) service_name);
310     } else {
311         if (controller){
312             de_add_data(service, DE_STRING, strlen(avrcp_default_controller_service_name), (uint8_t *) avrcp_default_controller_service_name);
313         } else {
314             de_add_data(service, DE_STRING, strlen(avrcp_defaul_target_service_name), (uint8_t *) avrcp_defaul_target_service_name);
315         }
316     }
317 
318     // 0x0100 "Provider Name"
319     de_add_number(service,  DE_UINT, DE_SIZE_16, 0x0102);
320     if (service_provider_name){
321         de_add_data(service,  DE_STRING, strlen(service_provider_name), (uint8_t *) service_provider_name);
322     } else {
323         if (controller){
324             de_add_data(service, DE_STRING, strlen(avrcp_default_controller_service_provider_name), (uint8_t *) avrcp_default_controller_service_provider_name);
325         } else {
326             de_add_data(service, DE_STRING, strlen(avrcp_default_target_service_provider_name), (uint8_t *) avrcp_default_target_service_provider_name);
327         }
328     }
329 
330     // 0x0311 "Supported Features"
331     de_add_number(service, DE_UINT, DE_SIZE_16, 0x0311);
332     de_add_number(service, DE_UINT, DE_SIZE_16, supported_features);
333 }
334 
335 static uint16_t avrcp_get_max_payload_size_for_avctp_packet_type(avrcp_connection_t * connection, avctp_packet_type_t avctp_packet_type){
336     uint16_t max_frame_size = btstack_min(l2cap_get_remote_mtu_for_local_cid(connection->l2cap_signaling_cid), AVRCP_MAX_AV_C_MESSAGE_FRAME_SIZE);
337 
338     switch (avctp_packet_type){
339         case AVCTP_SINGLE_PACKET:
340             return max_frame_size - 3;
341         case AVCTP_START_PACKET:
342             return max_frame_size - 4;
343         case AVCTP_CONTINUE_PACKET:
344         case AVCTP_END_PACKET:
345             return max_frame_size - 1;
346         default:
347             btstack_assert(false);
348             return 0;
349     }
350 }
351 
352 avctp_packet_type_t avrcp_get_avctp_packet_type(avrcp_connection_t * connection){
353     if (connection->data_offset == 0){
354         if (avrcp_get_max_payload_size_for_avctp_packet_type(connection, AVCTP_SINGLE_PACKET) >= connection->data_len){
355             return AVCTP_SINGLE_PACKET;
356         } else {
357             return AVCTP_START_PACKET;
358         }
359 
360     } else {
361         if ((connection->data_len - connection->data_offset) > avrcp_get_max_payload_size_for_avctp_packet_type(connection, AVCTP_CONTINUE_PACKET)){
362              return AVCTP_CONTINUE_PACKET;
363          } else {
364             return AVCTP_END_PACKET;
365          }
366     }
367 }
368 
369 uint8_t avctp_get_num_packets(uint16_t max_frame_size, uint16_t data_len, avrcp_command_opcode_t command_opcode){
370     if (command_opcode != AVRCP_CMD_OPCODE_VENDOR_DEPENDENT){
371         return 1;
372     }
373     uint16_t header_offset = 4; // AVCTP message: header (1), num_packets (1), pid (2)
374     switch (command_opcode){
375         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
376             header_offset += 10; // AVRCP message: cmd type (1), subunit (1), opcode (1), company (3), pdu id(1), AVRCP packet type (1), param_len (2)
377             break;
378         case AVRCP_CMD_OPCODE_PASS_THROUGH:
379             header_offset += 6;  // AVRCP message: cmd type (1), subunit (1), opcode (1), operation id (1), param_len (2)
380             break;
381         default:
382             return 1;
383     }
384     uint16_t num_remaining_bytes_of_data =  data_len - ( max_frame_size - header_offset );
385     uint8_t num_packets = 1;
386 
387     while (num_remaining_bytes_of_data > 0){
388         uint8_t bytes_to_copy = btstack_min(max_frame_size, num_remaining_bytes_of_data + 1); // 1 byte for AVCTP header
389         num_remaining_bytes_of_data -= bytes_to_copy;
390         num_packets++;
391     }
392     return num_packets;
393 }
394 
395 
396 avrcp_connection_t * avrcp_get_connection_for_bd_addr_for_role(avrcp_role_t role, bd_addr_t addr){
397     btstack_linked_list_iterator_t it;
398     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
399     while (btstack_linked_list_iterator_has_next(&it)){
400         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
401         if (connection->role != role) continue;
402         if (memcmp(addr, connection->remote_addr, 6) != 0) continue;
403         return connection;
404     }
405     return NULL;
406 }
407 
408 avrcp_connection_t * avrcp_get_connection_for_l2cap_signaling_cid_for_role(avrcp_role_t role, uint16_t l2cap_cid){
409     btstack_linked_list_iterator_t it;
410     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
411     while (btstack_linked_list_iterator_has_next(&it)){
412         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
413         if (connection->role != role) continue;
414         if (connection->l2cap_signaling_cid != l2cap_cid) continue;
415         return connection;
416     }
417     return NULL;
418 }
419 
420 avrcp_connection_t * avrcp_get_connection_for_avrcp_cid_for_role(avrcp_role_t role, uint16_t avrcp_cid){
421     btstack_linked_list_iterator_t it;
422     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
423     while (btstack_linked_list_iterator_has_next(&it)){
424         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
425         if (connection->role != role) continue;
426         if (connection->avrcp_cid != avrcp_cid) continue;
427         return connection;
428     }
429     return NULL;
430 }
431 
432 avrcp_connection_t * avrcp_get_connection_for_browsing_cid_for_role(avrcp_role_t role, uint16_t browsing_cid){
433     btstack_linked_list_iterator_t it;
434     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
435     while (btstack_linked_list_iterator_has_next(&it)){
436         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
437         if (connection->role != role) continue;
438         if (connection->avrcp_browsing_cid != browsing_cid) continue;
439         return connection;
440     }
441     return NULL;
442 }
443 
444 avrcp_connection_t * avrcp_get_connection_for_browsing_l2cap_cid_for_role(avrcp_role_t role, uint16_t browsing_l2cap_cid){
445     btstack_linked_list_iterator_t it;
446     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
447     while (btstack_linked_list_iterator_has_next(&it)){
448         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
449         if (connection->role != role) continue;
450         if (connection->browsing_connection &&  (connection->browsing_connection->l2cap_browsing_cid != browsing_l2cap_cid)) continue;
451         return connection;
452     }
453     return NULL;
454 }
455 
456 avrcp_browsing_connection_t * avrcp_get_browsing_connection_for_l2cap_cid_for_role(avrcp_role_t role, uint16_t l2cap_cid){
457     btstack_linked_list_iterator_t it;
458     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
459     while (btstack_linked_list_iterator_has_next(&it)){
460         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
461         if (connection->role != role) continue;
462         if (connection->browsing_connection && (connection->browsing_connection->l2cap_browsing_cid != l2cap_cid)) continue;
463         return connection->browsing_connection;
464     }
465     return NULL;
466 }
467 
468 void avrcp_request_can_send_now(avrcp_connection_t * connection, uint16_t l2cap_cid){
469     connection->wait_to_send = true;
470     l2cap_request_can_send_now_event(l2cap_cid);
471 }
472 
473 uint16_t avrcp_get_next_cid(avrcp_role_t role){
474     do {
475         if (avrcp_cid_counter == 0xffff) {
476             avrcp_cid_counter = 1;
477         } else {
478             avrcp_cid_counter++;
479         }
480     } while (avrcp_get_connection_for_avrcp_cid_for_role(role, avrcp_cid_counter) !=  NULL) ;
481     return avrcp_cid_counter;
482 }
483 
484 static avrcp_connection_t * avrcp_create_connection(avrcp_role_t role, bd_addr_t remote_addr){
485     avrcp_connection_t * connection = btstack_memory_avrcp_connection_get();
486     if (!connection){
487         log_error("Not enough memory to create connection for role %d", role);
488         return NULL;
489     }
490 
491     connection->state = AVCTP_CONNECTION_IDLE;
492     connection->role = role;
493 
494     connection->transaction_id = 0xFF;
495     connection->transaction_id_counter = 0;
496 
497     connection->max_num_fragments = 0xFF;
498 
499     // setup default unit / subunit info
500     connection->company_id = 0xffffff;
501     connection->unit_type = AVRCP_SUBUNIT_TYPE_PANEL;
502     connection->subunit_info_data_size = sizeof(avrcp_default_subunit_info);
503     connection->subunit_info_data = avrcp_default_subunit_info;
504 
505     log_info("avrcp_create_connection, role %d", role);
506     (void)memcpy(connection->remote_addr, remote_addr, 6);
507     btstack_linked_list_add(&avrcp_connections, (btstack_linked_item_t *) connection);
508     return connection;
509 }
510 
511 static void avrcp_finalize_connection(avrcp_connection_t * connection){
512     btstack_run_loop_remove_timer(&connection->retry_timer);
513     btstack_linked_list_remove(&avrcp_connections, (btstack_linked_item_t*) connection);
514     btstack_memory_avrcp_connection_free(connection);
515 }
516 
517 static void avrcp_emit_connection_established(uint16_t avrcp_cid, bd_addr_t addr, hci_con_handle_t con_handle, uint8_t status){
518     btstack_assert(avrcp_callback != NULL);
519 
520     uint8_t event[14];
521     int pos = 0;
522     event[pos++] = HCI_EVENT_AVRCP_META;
523     event[pos++] = sizeof(event) - 2;
524     event[pos++] = AVRCP_SUBEVENT_CONNECTION_ESTABLISHED;
525     event[pos++] = status;
526     little_endian_store_16(event, pos, avrcp_cid);
527     pos += 2;
528     reverse_bd_addr(addr,&event[pos]);
529     pos += 6;
530     little_endian_store_16(event, pos, con_handle);
531     pos += 2;
532     (*avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
533 }
534 
535 static void avrcp_emit_connection_closed(uint16_t avrcp_cid){
536     btstack_assert(avrcp_callback != NULL);
537 
538     uint8_t event[5];
539     int pos = 0;
540     event[pos++] = HCI_EVENT_AVRCP_META;
541     event[pos++] = sizeof(event) - 2;
542     event[pos++] = AVRCP_SUBEVENT_CONNECTION_RELEASED;
543     little_endian_store_16(event, pos, avrcp_cid);
544     pos += 2;
545     (*avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
546 }
547 
548 uint16_t avrcp_sdp_query_browsing_l2cap_psm(void){
549     return avrcp_sdp_query_context.browsing_l2cap_psm;
550 }
551 
552 void avrcp_handle_sdp_client_query_attribute_value(uint8_t *packet){
553     des_iterator_t des_list_it;
554     des_iterator_t prot_it;
555 
556     // Handle new SDP record
557     if (sdp_event_query_attribute_byte_get_record_id(packet) != avrcp_sdp_query_context.record_id) {
558         avrcp_sdp_query_context.record_id = sdp_event_query_attribute_byte_get_record_id(packet);
559         avrcp_sdp_query_context.parse_sdp_record = 0;
560         // log_info("SDP Record: Nr: %d", record_id);
561     }
562 
563     if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= avrcp_sdp_query_attribute_value_buffer_size) {
564         avrcp_sdp_query_attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
565 
566         if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
567             switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
568                 case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
569                     if (de_get_element_type(avrcp_sdp_query_attribute_value) != DE_DES) break;
570                     for (des_iterator_init(&des_list_it, avrcp_sdp_query_attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
571                         uint8_t * element = des_iterator_get_element(&des_list_it);
572                         if (de_get_element_type(element) != DE_UUID) continue;
573                         uint32_t uuid = de_get_uuid32(element);
574                         switch (uuid){
575                             case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET:
576                             case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL:
577                             case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER:
578                                 avrcp_sdp_query_context.parse_sdp_record = 1;
579                                 break;
580                             default:
581                                 break;
582                         }
583                     }
584                     break;
585 
586                 case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
587                     if (!avrcp_sdp_query_context.parse_sdp_record) break;
588                     // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
589                     for (des_iterator_init(&des_list_it, avrcp_sdp_query_attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
590                         uint8_t       *des_element;
591                         uint8_t       *element;
592                         uint32_t       uuid;
593 
594                         if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
595 
596                         des_element = des_iterator_get_element(&des_list_it);
597                         des_iterator_init(&prot_it, des_element);
598                         element = des_iterator_get_element(&prot_it);
599 
600                         if (de_get_element_type(element) != DE_UUID) continue;
601 
602                         uuid = de_get_uuid32(element);
603                         des_iterator_next(&prot_it);
604                         switch (uuid){
605                             case BLUETOOTH_PROTOCOL_L2CAP:
606                                 if (!des_iterator_has_more(&prot_it)) continue;
607                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &avrcp_sdp_query_context.avrcp_l2cap_psm);
608                                 break;
609                             case BLUETOOTH_PROTOCOL_AVCTP:
610                                 if (!des_iterator_has_more(&prot_it)) continue;
611                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &avrcp_sdp_query_context.avrcp_version);
612                                 break;
613                             default:
614                                 break;
615                         }
616                     }
617                 }
618                     break;
619                 case BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS: {
620                     // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
621                     if (!avrcp_sdp_query_context.parse_sdp_record) break;
622                     if (de_get_element_type(avrcp_sdp_query_attribute_value) != DE_DES) break;
623 
624                     des_iterator_t des_list_0_it;
625                     uint8_t       *element_0;
626 
627                     des_iterator_init(&des_list_0_it, avrcp_sdp_query_attribute_value);
628                     element_0 = des_iterator_get_element(&des_list_0_it);
629 
630                     for (des_iterator_init(&des_list_it, element_0); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
631                         uint8_t       *des_element;
632                         uint8_t       *element;
633                         uint32_t       uuid;
634 
635                         if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
636 
637                         des_element = des_iterator_get_element(&des_list_it);
638                         des_iterator_init(&prot_it, des_element);
639                         element = des_iterator_get_element(&prot_it);
640 
641                         if (de_get_element_type(element) != DE_UUID) continue;
642 
643                         uuid = de_get_uuid32(element);
644                         des_iterator_next(&prot_it);
645                         switch (uuid){
646                             case BLUETOOTH_PROTOCOL_L2CAP:
647                                 if (!des_iterator_has_more(&prot_it)) continue;
648                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &avrcp_sdp_query_context.browsing_l2cap_psm);
649                                 break;
650                             case BLUETOOTH_PROTOCOL_AVCTP:
651                                 if (!des_iterator_has_more(&prot_it)) continue;
652                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &avrcp_sdp_query_context.browsing_version);
653                                 break;
654                             default:
655                                 break;
656                         }
657                     }
658                 }
659                     break;
660                 default:
661                     break;
662             }
663         }
664     } else {
665         log_error("SDP attribute value buffer size exceeded: available %d, required %d", avrcp_sdp_query_attribute_value_buffer_size, sdp_event_query_attribute_byte_get_attribute_length(packet));
666     }
667 }
668 
669 static void avrcp_handle_sdp_query_failed(avrcp_connection_t * connection, uint8_t status){
670     if (connection == NULL) return;
671     log_info("AVRCP: SDP query failed with status 0x%02x.", status);
672     avrcp_emit_connection_established(connection->avrcp_cid, connection->remote_addr, connection->con_handle, status);
673     avrcp_finalize_connection(connection);
674 }
675 
676 static void avrcp_handle_sdp_query_succeeded(avrcp_connection_t * connection){
677     if (connection == NULL) return;
678     connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
679     connection->avrcp_l2cap_psm = avrcp_sdp_query_context.avrcp_l2cap_psm;
680     connection->browsing_version = avrcp_sdp_query_context.browsing_version;
681     connection->browsing_l2cap_psm = avrcp_sdp_query_context.browsing_l2cap_psm;
682 }
683 
684 static void avrcp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
685     UNUSED(packet_type);
686     UNUSED(channel);
687     UNUSED(size);
688 
689     bool state_ok = true;
690     avrcp_connection_t * avrcp_target_connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_sdp_query_context.avrcp_cid);
691     if (!avrcp_target_connection || avrcp_target_connection->state != AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE) {
692         state_ok = false;
693     }
694     avrcp_connection_t * avrcp_controller_connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_sdp_query_context.avrcp_cid);
695     if (!avrcp_controller_connection || avrcp_controller_connection->state != AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE) {
696         state_ok = false;
697     }
698     if (!state_ok){
699         // something wrong, nevertheless, start next sdp query if this one is complete
700         if (hci_event_packet_get_type(packet) == SDP_EVENT_QUERY_COMPLETE){
701             (void) sdp_client_register_query_callback(&avrcp_sdp_query_registration);
702         }
703         return;
704     }
705 
706     uint8_t status;
707 
708     switch (hci_event_packet_get_type(packet)){
709         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
710             avrcp_handle_sdp_client_query_attribute_value(packet);
711             return;
712 
713         case SDP_EVENT_QUERY_COMPLETE:
714             status = sdp_event_query_complete_get_status(packet);
715 
716             if (status != ERROR_CODE_SUCCESS){
717                 avrcp_handle_sdp_query_failed(avrcp_controller_connection, status);
718                 avrcp_handle_sdp_query_failed(avrcp_target_connection, status);
719                 break;
720             }
721 
722             if (!avrcp_sdp_query_context.avrcp_l2cap_psm){
723                 avrcp_handle_sdp_query_failed(avrcp_controller_connection, SDP_SERVICE_NOT_FOUND);
724                 avrcp_handle_sdp_query_failed(avrcp_target_connection, SDP_SERVICE_NOT_FOUND);
725                 break;
726             }
727 
728             avrcp_handle_sdp_query_succeeded(avrcp_controller_connection);
729             avrcp_handle_sdp_query_succeeded(avrcp_target_connection);
730 
731             l2cap_create_channel(&avrcp_packet_handler, avrcp_target_connection->remote_addr, avrcp_sdp_query_context.avrcp_l2cap_psm, l2cap_max_mtu(), NULL);
732             break;
733 
734         default:
735             return;
736     }
737 
738     // register the SDP Query request to check if there is another connection waiting for the query
739     // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
740     (void) sdp_client_register_query_callback(&avrcp_sdp_query_registration);
741 }
742 
743 
744 static avrcp_connection_t * avrcp_handle_incoming_connection_for_role(avrcp_role_t role, avrcp_connection_t * connection, bd_addr_t event_addr, hci_con_handle_t con_handle, uint16_t local_cid, uint16_t avrcp_cid){
745     if (connection == NULL){
746         connection = avrcp_create_connection(role, event_addr);
747     }
748     if (connection) {
749         connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
750         connection->l2cap_signaling_cid = local_cid;
751         connection->avrcp_cid = avrcp_cid;
752         connection->con_handle = con_handle;
753         btstack_run_loop_remove_timer(&connection->retry_timer);
754     }
755     return connection;
756 }
757 
758 static void avrcp_handle_open_connection(avrcp_connection_t * connection, hci_con_handle_t con_handle, uint16_t local_cid, uint16_t l2cap_mtu){
759     connection->l2cap_signaling_cid = local_cid;
760     connection->l2cap_mtu = l2cap_mtu;
761     connection->con_handle = con_handle;
762     connection->incoming_declined = false;
763     connection->song_length_ms = 0xFFFFFFFF;
764     connection->song_position_ms = 0xFFFFFFFF;
765     connection->playback_status = AVRCP_PLAYBACK_STATUS_STOPPED;
766     connection->state = AVCTP_CONNECTION_OPENED;
767 
768     log_info("L2CAP_EVENT_CHANNEL_OPENED avrcp_cid 0x%02x, l2cap_signaling_cid 0x%02x, role %d, state %d", connection->avrcp_cid, connection->l2cap_signaling_cid, connection->role, connection->state);
769 }
770 
771 static void avrcp_retry_timer_timeout_handler(btstack_timer_source_t * timer){
772     uint16_t avrcp_cid = (uint16_t)(uintptr_t) btstack_run_loop_get_timer_context(timer);
773     avrcp_connection_t * connection_controller = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
774     if (connection_controller == NULL) return;
775     avrcp_connection_t * connection_target = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
776     if (connection_target == NULL) return;
777 
778     if (connection_controller->state == AVCTP_CONNECTION_W2_L2CAP_RETRY){
779         connection_controller->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
780         connection_target->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
781         l2cap_create_channel(&avrcp_packet_handler, connection_controller->remote_addr, connection_controller->avrcp_l2cap_psm, l2cap_max_mtu(), NULL);
782     }
783 }
784 
785 static void avrcp_retry_timer_start(avrcp_connection_t * connection){
786     btstack_run_loop_set_timer_handler(&connection->retry_timer, avrcp_retry_timer_timeout_handler);
787     btstack_run_loop_set_timer_context(&connection->retry_timer, (void *)(uintptr_t)connection->avrcp_cid);
788 
789     // add some jitter/randomness to reconnect delay
790     uint32_t timeout = 100 + (btstack_run_loop_get_time_ms() & 0x7F);
791     btstack_run_loop_set_timer(&connection->retry_timer, timeout);
792 
793     btstack_run_loop_add_timer(&connection->retry_timer);
794 }
795 
796 static avrcp_frame_type_t avrcp_get_frame_type(uint8_t header){
797     return (avrcp_frame_type_t)((header & 0x02) >> 1);
798 }
799 
800 static void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
801     UNUSED(channel);
802     UNUSED(size);
803     bd_addr_t event_addr;
804     uint16_t local_cid;
805     uint16_t l2cap_mtu;
806     uint8_t  status;
807     bool decline_connection;
808     bool outoing_active;
809     hci_con_handle_t con_handle;
810 
811     avrcp_connection_t * connection_controller;
812     avrcp_connection_t * connection_target;
813     bool can_send;
814 
815     switch (packet_type) {
816         case HCI_EVENT_PACKET:
817             switch (hci_event_packet_get_type(packet)) {
818 
819                 case L2CAP_EVENT_INCOMING_CONNECTION:
820                     btstack_assert(avrcp_controller_packet_handler != NULL);
821                     btstack_assert(avrcp_target_packet_handler != NULL);
822 
823                     l2cap_event_incoming_connection_get_address(packet, event_addr);
824                     local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
825                     con_handle = l2cap_event_incoming_connection_get_handle(packet);
826 
827                     outoing_active = false;
828                     connection_target = avrcp_get_connection_for_bd_addr_for_role(AVRCP_TARGET, event_addr);
829                     if (connection_target != NULL){
830                         if (connection_target->state == AVCTP_CONNECTION_W4_L2CAP_CONNECTED){
831                             outoing_active = true;
832                             connection_target->incoming_declined = true;
833                         }
834                     }
835 
836                     connection_controller = avrcp_get_connection_for_bd_addr_for_role(AVRCP_CONTROLLER, event_addr);
837                     if (connection_controller != NULL){
838                         if (connection_controller->state == AVCTP_CONNECTION_W4_L2CAP_CONNECTED) {
839                             outoing_active = true;
840                             connection_controller->incoming_declined = true;
841                         }
842                     }
843 
844                     decline_connection = outoing_active;
845                     if (decline_connection == false){
846                         uint16_t avrcp_cid;
847                         if ((connection_controller == NULL) || (connection_target == NULL)){
848                             avrcp_cid = avrcp_get_next_cid(AVRCP_CONTROLLER);
849                         } else {
850                             avrcp_cid = connection_controller->avrcp_cid;
851                         }
852                         // create two connection objects (both)
853                         connection_target     = avrcp_handle_incoming_connection_for_role(AVRCP_TARGET, connection_target, event_addr, con_handle, local_cid, avrcp_cid);
854                         connection_controller = avrcp_handle_incoming_connection_for_role(AVRCP_CONTROLLER, connection_controller, event_addr, con_handle, local_cid, avrcp_cid);
855                         if ((connection_target == NULL) || (connection_controller == NULL)){
856                             decline_connection = true;
857                             if (connection_target) {
858                                 avrcp_finalize_connection(connection_target);
859                             }
860                             if (connection_controller) {
861                                 avrcp_finalize_connection(connection_controller);
862                             }
863                         }
864                     }
865                     if (decline_connection){
866                         l2cap_decline_connection(local_cid);
867                     } else {
868                         log_info("AVRCP: L2CAP_EVENT_INCOMING_CONNECTION local cid 0x%02x, state %d", local_cid, connection_controller->state);
869                         l2cap_accept_connection(local_cid);
870                     }
871                     break;
872 
873                 case L2CAP_EVENT_CHANNEL_OPENED:
874                     l2cap_event_channel_opened_get_address(packet, event_addr);
875                     status = l2cap_event_channel_opened_get_status(packet);
876                     local_cid = l2cap_event_channel_opened_get_local_cid(packet);
877                     l2cap_mtu = l2cap_event_channel_opened_get_remote_mtu(packet);
878                     con_handle = l2cap_event_channel_opened_get_handle(packet);
879 
880                     connection_controller = avrcp_get_connection_for_bd_addr_for_role(AVRCP_CONTROLLER, event_addr);
881                     connection_target = avrcp_get_connection_for_bd_addr_for_role(AVRCP_TARGET, event_addr);
882 
883                     // incoming: structs are already created in L2CAP_EVENT_INCOMING_CONNECTION
884                     // outgoing: structs are cteated in avrcp_connect()
885                     if ((connection_controller == NULL) || (connection_target == NULL)) {
886                         break;
887                     }
888 
889                     switch (status){
890                         case ERROR_CODE_SUCCESS:
891                             avrcp_handle_open_connection(connection_target, con_handle, local_cid, l2cap_mtu);
892                             avrcp_handle_open_connection(connection_controller, con_handle, local_cid, l2cap_mtu);
893                             avrcp_emit_connection_established(connection_controller->avrcp_cid, event_addr, con_handle, status);
894                             return;
895                         case L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_RESOURCES:
896                             if (connection_controller->incoming_declined == true){
897                                 log_info("Incoming connection was declined, and the outgoing failed");
898                                 connection_controller->state = AVCTP_CONNECTION_W2_L2CAP_RETRY;
899                                 connection_controller->incoming_declined = false;
900                                 connection_target->state = AVCTP_CONNECTION_W2_L2CAP_RETRY;
901                                 connection_target->incoming_declined = false;
902                                 avrcp_retry_timer_start(connection_controller);
903                                 return;
904                             }
905                             break;
906                         default:
907                             break;
908                     }
909                     log_info("L2CAP connection to connection %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
910                     avrcp_emit_connection_established(connection_controller->avrcp_cid, event_addr, con_handle, status);
911                     avrcp_finalize_connection(connection_controller);
912                     avrcp_finalize_connection(connection_target);
913 
914                     break;
915 
916                 case L2CAP_EVENT_CHANNEL_CLOSED:
917                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
918 
919                     connection_controller = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, local_cid);
920                     connection_target = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, local_cid);
921                     if ((connection_controller == NULL) || (connection_target == NULL)) {
922                         break;
923                     }
924                     avrcp_emit_connection_closed(connection_controller->avrcp_cid);
925                     avrcp_finalize_connection(connection_controller);
926                     avrcp_finalize_connection(connection_target);
927                     break;
928 
929                 case L2CAP_EVENT_CAN_SEND_NOW:
930                     local_cid = l2cap_event_can_send_now_get_local_cid(packet);
931                     can_send = true;
932 
933                     connection_target = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, local_cid);
934                     if ((connection_target != NULL) && connection_target->wait_to_send){
935                         connection_target->wait_to_send = false;
936                         (*avrcp_target_packet_handler)(HCI_EVENT_PACKET, channel, packet, size);
937                         can_send = false;
938                     }
939 
940                     connection_controller = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, local_cid);
941                     if ((connection_controller != NULL) && connection_controller->wait_to_send){
942                         if (can_send){
943                             connection_controller->wait_to_send = false;
944                             (*avrcp_controller_packet_handler)(HCI_EVENT_PACKET, channel, packet, size);
945                         } else {
946                             l2cap_request_can_send_now_event(local_cid);
947                         }
948                     }
949                     break;
950 
951                 default:
952                     break;
953             }
954             break;
955 
956         case L2CAP_DATA_PACKET:
957             switch (avrcp_get_frame_type(packet[0])){
958                 case AVRCP_RESPONSE_FRAME:
959                     (*avrcp_controller_packet_handler)(packet_type, channel, packet, size);
960                     break;
961                 case AVRCP_COMMAND_FRAME:
962                 default:    // make compiler happy
963                     (*avrcp_target_packet_handler)(packet_type, channel, packet, size);
964                     break;
965             }
966             break;
967 
968         default:
969             break;
970     }
971 }
972 
973 uint8_t avrcp_disconnect(uint16_t avrcp_cid){
974     avrcp_connection_t * connection_controller = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
975     if (!connection_controller){
976         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
977     }
978     avrcp_connection_t * connection_target = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
979     if (!connection_target){
980         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
981     }
982     if (connection_controller->browsing_connection){
983         l2cap_disconnect(connection_controller->browsing_connection->l2cap_browsing_cid);
984     }
985     l2cap_disconnect(connection_controller->l2cap_signaling_cid);
986     return ERROR_CODE_SUCCESS;
987 }
988 
989 static void avrcp_handle_start_sdp_client_query(void * context){
990     UNUSED(context);
991 
992     btstack_linked_list_iterator_t it;
993     btstack_linked_list_iterator_init(&it, &avrcp_connections);
994     while (btstack_linked_list_iterator_has_next(&it)){
995         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
996 
997         if (connection->state != AVCTP_CONNECTION_W2_SEND_SDP_QUERY) continue;
998         connection->state = AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE;
999 
1000         // prevent triggering SDP query twice (for each role once)
1001         avrcp_connection_t * connection_with_opposite_role;
1002         switch (connection->role){
1003             case AVRCP_CONTROLLER:
1004                 connection_with_opposite_role = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, connection->avrcp_cid);
1005                 break;
1006             case AVRCP_TARGET:
1007                 connection_with_opposite_role = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, connection->avrcp_cid);
1008                 break;
1009             default:
1010                 btstack_assert(false);
1011                 return;
1012         }
1013         connection_with_opposite_role->state = AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE;
1014 
1015         avrcp_sdp_query_context.avrcp_l2cap_psm = 0;
1016         avrcp_sdp_query_context.avrcp_version  = 0;
1017         avrcp_sdp_query_context.avrcp_cid = connection->avrcp_cid;
1018         sdp_client_query_uuid16(&avrcp_handle_sdp_client_query_result, (uint8_t *) connection->remote_addr, BLUETOOTH_PROTOCOL_AVCTP);
1019         return;
1020     }
1021 }
1022 
1023 uint8_t avrcp_connect(bd_addr_t remote_addr, uint16_t * avrcp_cid){
1024     btstack_assert(avrcp_controller_packet_handler != NULL);
1025     btstack_assert(avrcp_target_packet_handler != NULL);
1026 
1027     avrcp_connection_t * connection_controller = avrcp_get_connection_for_bd_addr_for_role(AVRCP_CONTROLLER, remote_addr);
1028     if (connection_controller){
1029         return ERROR_CODE_COMMAND_DISALLOWED;
1030     }
1031     avrcp_connection_t * connection_target = avrcp_get_connection_for_bd_addr_for_role(AVRCP_TARGET, remote_addr);
1032     if (connection_target){
1033         return ERROR_CODE_COMMAND_DISALLOWED;
1034     }
1035 
1036     uint16_t cid = avrcp_get_next_cid(AVRCP_CONTROLLER);
1037 
1038     connection_controller = avrcp_create_connection(AVRCP_CONTROLLER, remote_addr);
1039     if (!connection_controller) return BTSTACK_MEMORY_ALLOC_FAILED;
1040 
1041     connection_target = avrcp_create_connection(AVRCP_TARGET, remote_addr);
1042     if (!connection_target){
1043         avrcp_finalize_connection(connection_controller);
1044         return BTSTACK_MEMORY_ALLOC_FAILED;
1045     }
1046 
1047     if (avrcp_cid != NULL){
1048         *avrcp_cid = cid;
1049     }
1050 
1051     connection_controller->state = AVCTP_CONNECTION_W2_SEND_SDP_QUERY;
1052     connection_controller->avrcp_cid = cid;
1053 
1054     connection_target->state     = AVCTP_CONNECTION_W2_SEND_SDP_QUERY;
1055     connection_target->avrcp_cid = cid;
1056 
1057     avrcp_sdp_query_registration.callback = &avrcp_handle_start_sdp_client_query;
1058     // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
1059     (void) sdp_client_register_query_callback(&avrcp_sdp_query_registration);
1060     return ERROR_CODE_SUCCESS;
1061 }
1062 
1063 void avrcp_init(void){
1064     avrcp_connections = NULL;
1065     if (avrcp_l2cap_service_registered) return;
1066 
1067     int status = l2cap_register_service(&avrcp_packet_handler, BLUETOOTH_PSM_AVCTP, 0xffff, gap_get_security_level());
1068     if (status != ERROR_CODE_SUCCESS) return;
1069     avrcp_l2cap_service_registered = true;
1070 }
1071 
1072 void avrcp_deinit(void){
1073     avrcp_l2cap_service_registered = false;
1074 
1075     avrcp_cid_counter = 0;
1076     avrcp_connections = NULL;
1077 
1078     avrcp_callback = NULL;
1079     avrcp_controller_packet_handler = NULL;
1080     avrcp_target_packet_handler = NULL;
1081 
1082     (void) memset(&avrcp_sdp_query_registration, 0, sizeof(avrcp_sdp_query_registration));
1083     (void) memset(&avrcp_sdp_query_context, 0, sizeof(avrcp_sdp_query_context_t));
1084     (void) memset(avrcp_sdp_query_attribute_value, 0, sizeof(avrcp_sdp_query_attribute_value));
1085 }
1086 
1087 void avrcp_register_controller_packet_handler(btstack_packet_handler_t callback){
1088     avrcp_controller_packet_handler = callback;
1089 }
1090 
1091 void avrcp_register_target_packet_handler(btstack_packet_handler_t callback){
1092     avrcp_target_packet_handler = callback;
1093 }
1094 
1095 void avrcp_register_packet_handler(btstack_packet_handler_t callback){
1096     btstack_assert(callback != NULL);
1097     avrcp_callback = callback;
1098 }
1099 
1100 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
1101 #define FUZZ_CID 0x44
1102 #define FUZZ_CON_HANDLE 0x0001
1103 static bd_addr_t remote_addr = { 0x33, 0x33, 0x33, 0x33, 0x33, 0x33 };
1104 void avrcp_init_fuzz(void){
1105     // setup avrcp connections for cid
1106     avrcp_connection_t * connection_controller = avrcp_create_connection(AVRCP_CONTROLLER, remote_addr);
1107     avrcp_connection_t * connection_target     = avrcp_create_connection(AVRCP_TARGET, remote_addr);
1108     avrcp_handle_open_connection(connection_controller, FUZZ_CON_HANDLE, FUZZ_CID, 999);
1109     avrcp_handle_open_connection(connection_target, FUZZ_CON_HANDLE, FUZZ_CID, 999);
1110 }
1111 void avrcp_packet_handler_fuzz(uint8_t *packet, uint16_t size){
1112     avrcp_packet_handler(L2CAP_DATA_PACKET, FUZZ_CID, packet, size);
1113 }
1114 #endif