xref: /btstack/src/classic/avrcp.c (revision d6c2d4bc1a29aa76f6dc9e077d641563083dbd35)
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 uint16_t avctp_get_num_bytes_for_header(avctp_packet_type_t avctp_packet_type) {
336     switch (avctp_packet_type){
337         case AVCTP_SINGLE_PACKET:
338             // AVCTP message: transport header (1), pid (2)
339             return 3;
340         case AVCTP_START_PACKET:
341             // AVCTP message: transport header (1), num_packets (1), pid (2)
342             return 4;
343         default:
344             // AVCTP message: transport header (1)
345             return 1;
346     }
347 }
348 
349 uint16_t avrcp_get_num_bytes_for_header(avrcp_command_opcode_t command_opcode, avctp_packet_type_t avctp_packet_type) {
350     switch (avctp_packet_type){
351         case AVCTP_SINGLE_PACKET:
352         case AVCTP_START_PACKET:
353             break;
354         default:
355             return 0;
356     }
357 
358     uint16_t offset = 3; // AVRCP message: cmd type (1), subunit (1), opcode (1)
359     switch (command_opcode){
360         case AVRCP_CMD_OPCODE_VENDOR_DEPENDENT:
361             offset += 7; // AVRCP message:  company (3), pdu id(1), AVRCP packet type (1), param_len (2)
362             break;
363         case AVRCP_CMD_OPCODE_PASS_THROUGH:
364             offset += 3;  // AVRCP message: operation id (1), param_len (2)
365             break;
366         default:
367             break;
368     }
369     return offset;
370 }
371 
372 static uint16_t avrcp_get_num_free_bytes_for_payload(uint16_t l2cap_mtu, avrcp_command_opcode_t command_opcode, avctp_packet_type_t avctp_packet_type){
373     uint16_t max_frame_size = btstack_min(l2cap_mtu, AVRCP_MAX_AV_C_MESSAGE_FRAME_SIZE);
374     uint16_t payload_offset = avctp_get_num_bytes_for_header(avctp_packet_type) +
375                               avrcp_get_num_bytes_for_header(command_opcode, avctp_packet_type);
376 
377     btstack_assert(max_frame_size >= payload_offset);
378     return (max_frame_size - payload_offset);
379 }
380 
381 
382 avctp_packet_type_t avctp_get_packet_type(avrcp_connection_t * connection, uint16_t * max_payload_size){
383     if (connection->l2cap_mtu >= AVRCP_MAX_AV_C_MESSAGE_FRAME_SIZE){
384         return AVCTP_SINGLE_PACKET;
385     }
386 
387     if (connection->data_offset == 0){
388         uint16_t max_payload_size_for_single_packet = avrcp_get_num_free_bytes_for_payload(connection->l2cap_mtu,
389                                                                  connection->command_opcode,
390                                                                  AVCTP_SINGLE_PACKET);
391         if (max_payload_size_for_single_packet >= connection->data_len){
392             *max_payload_size = max_payload_size_for_single_packet;
393             return AVCTP_SINGLE_PACKET;
394         } else {
395             uint16_t max_payload_size_for_start_packet = max_payload_size_for_single_packet - 1;
396             *max_payload_size = max_payload_size_for_start_packet;
397             return AVCTP_START_PACKET;
398         }
399     } else {
400         // both packet types have the same single byte AVCTP header
401         *max_payload_size = avrcp_get_num_free_bytes_for_payload(connection->l2cap_mtu,
402                                                                  connection->command_opcode,
403                                                                  AVCTP_CONTINUE_PACKET);
404         if ((connection->data_len - connection->data_offset) > *max_payload_size){
405             return AVCTP_CONTINUE_PACKET;
406         } else {
407             return AVCTP_END_PACKET;
408         }
409     }
410 }
411 
412 avrcp_packet_type_t avrcp_get_packet_type(avrcp_connection_t * connection){
413     switch (connection->avctp_packet_type) {
414         case AVCTP_SINGLE_PACKET:
415         case AVCTP_START_PACKET:
416             break;
417         default:
418             return connection->avrcp_packet_type;
419     }
420 
421     uint16_t payload_offset = avctp_get_num_bytes_for_header(connection->avctp_packet_type) +
422                               avrcp_get_num_bytes_for_header(connection->command_opcode, connection->avctp_packet_type);
423     uint16_t bytes_to_send = (connection->data_len - connection->data_offset) + payload_offset;
424 
425     if (connection->data_offset == 0){
426         if (bytes_to_send <= AVRCP_MAX_AV_C_MESSAGE_FRAME_SIZE){
427             return AVRCP_SINGLE_PACKET;
428         } else {
429             return AVRCP_START_PACKET;
430         }
431     } else {
432         if (bytes_to_send > AVRCP_MAX_AV_C_MESSAGE_FRAME_SIZE){
433             return AVRCP_CONTINUE_PACKET;
434         } else {
435             return AVRCP_END_PACKET;
436         }
437     }
438 }
439 
440 avrcp_connection_t * avrcp_get_connection_for_bd_addr_for_role(avrcp_role_t role, bd_addr_t addr){
441     btstack_linked_list_iterator_t it;
442     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
443     while (btstack_linked_list_iterator_has_next(&it)){
444         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
445         if (connection->role != role) continue;
446         if (memcmp(addr, connection->remote_addr, 6) != 0) continue;
447         return connection;
448     }
449     return NULL;
450 }
451 
452 avrcp_connection_t * avrcp_get_connection_for_l2cap_signaling_cid_for_role(avrcp_role_t role, uint16_t l2cap_cid){
453     btstack_linked_list_iterator_t it;
454     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
455     while (btstack_linked_list_iterator_has_next(&it)){
456         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
457         if (connection->role != role) continue;
458         if (connection->l2cap_signaling_cid != l2cap_cid) continue;
459         return connection;
460     }
461     return NULL;
462 }
463 
464 avrcp_connection_t * avrcp_get_connection_for_avrcp_cid_for_role(avrcp_role_t role, uint16_t avrcp_cid){
465     btstack_linked_list_iterator_t it;
466     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
467     while (btstack_linked_list_iterator_has_next(&it)){
468         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
469         if (connection->role != role) continue;
470         if (connection->avrcp_cid != avrcp_cid) continue;
471         return connection;
472     }
473     return NULL;
474 }
475 
476 avrcp_connection_t * avrcp_get_connection_for_browsing_cid_for_role(avrcp_role_t role, uint16_t browsing_cid){
477     btstack_linked_list_iterator_t it;
478     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
479     while (btstack_linked_list_iterator_has_next(&it)){
480         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
481         if (connection->role != role) continue;
482         if (connection->avrcp_browsing_cid != browsing_cid) continue;
483         return connection;
484     }
485     return NULL;
486 }
487 
488 avrcp_connection_t * avrcp_get_connection_for_browsing_l2cap_cid_for_role(avrcp_role_t role, uint16_t browsing_l2cap_cid){
489     btstack_linked_list_iterator_t it;
490     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
491     while (btstack_linked_list_iterator_has_next(&it)){
492         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
493         if (connection->role != role) continue;
494         if (connection->browsing_connection &&  (connection->browsing_connection->l2cap_browsing_cid != browsing_l2cap_cid)) continue;
495         return connection;
496     }
497     return NULL;
498 }
499 
500 avrcp_browsing_connection_t * avrcp_get_browsing_connection_for_l2cap_cid_for_role(avrcp_role_t role, uint16_t l2cap_cid){
501     btstack_linked_list_iterator_t it;
502     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &avrcp_connections);
503     while (btstack_linked_list_iterator_has_next(&it)){
504         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
505         if (connection->role != role) continue;
506         if (connection->browsing_connection && (connection->browsing_connection->l2cap_browsing_cid != l2cap_cid)) continue;
507         return connection->browsing_connection;
508     }
509     return NULL;
510 }
511 
512 void avrcp_request_can_send_now(avrcp_connection_t * connection, uint16_t l2cap_cid){
513     connection->wait_to_send = true;
514     l2cap_request_can_send_now_event(l2cap_cid);
515 }
516 
517 uint16_t avrcp_get_next_cid(avrcp_role_t role){
518     do {
519         if (avrcp_cid_counter == 0xffff) {
520             avrcp_cid_counter = 1;
521         } else {
522             avrcp_cid_counter++;
523         }
524     } while (avrcp_get_connection_for_avrcp_cid_for_role(role, avrcp_cid_counter) !=  NULL) ;
525     return avrcp_cid_counter;
526 }
527 
528 static avrcp_connection_t * avrcp_create_connection(avrcp_role_t role, bd_addr_t remote_addr){
529     avrcp_connection_t * connection = btstack_memory_avrcp_connection_get();
530     if (!connection){
531         log_error("Not enough memory to create connection for role %d", role);
532         return NULL;
533     }
534 
535     connection->state = AVCTP_CONNECTION_IDLE;
536     connection->role = role;
537 
538     connection->transaction_id = 0xFF;
539     connection->transaction_id_counter = 0;
540 
541     connection->controller_max_num_fragments = 0xFF;
542 
543     // setup default unit / subunit info
544     connection->company_id = 0xffffff;
545     connection->target_unit_type = AVRCP_SUBUNIT_TYPE_PANEL;
546     connection->target_subunit_info_data_size = sizeof(avrcp_default_subunit_info);
547     connection->target_subunit_info_data = avrcp_default_subunit_info;
548 
549     log_info("avrcp_create_connection, role %d", role);
550     (void)memcpy(connection->remote_addr, remote_addr, 6);
551     btstack_linked_list_add(&avrcp_connections, (btstack_linked_item_t *) connection);
552     return connection;
553 }
554 
555 static void avrcp_finalize_connection(avrcp_connection_t * connection){
556     btstack_run_loop_remove_timer(&connection->retry_timer);
557     btstack_linked_list_remove(&avrcp_connections, (btstack_linked_item_t*) connection);
558     btstack_memory_avrcp_connection_free(connection);
559 }
560 
561 static void avrcp_emit_connection_established(uint16_t avrcp_cid, bd_addr_t addr, hci_con_handle_t con_handle, uint8_t status){
562     btstack_assert(avrcp_callback != NULL);
563 
564     uint8_t event[14];
565     int pos = 0;
566     event[pos++] = HCI_EVENT_AVRCP_META;
567     event[pos++] = sizeof(event) - 2;
568     event[pos++] = AVRCP_SUBEVENT_CONNECTION_ESTABLISHED;
569     event[pos++] = status;
570     little_endian_store_16(event, pos, avrcp_cid);
571     pos += 2;
572     reverse_bd_addr(addr,&event[pos]);
573     pos += 6;
574     little_endian_store_16(event, pos, con_handle);
575     pos += 2;
576     (*avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
577 }
578 
579 static void avrcp_emit_connection_closed(uint16_t avrcp_cid){
580     btstack_assert(avrcp_callback != NULL);
581 
582     uint8_t event[5];
583     int pos = 0;
584     event[pos++] = HCI_EVENT_AVRCP_META;
585     event[pos++] = sizeof(event) - 2;
586     event[pos++] = AVRCP_SUBEVENT_CONNECTION_RELEASED;
587     little_endian_store_16(event, pos, avrcp_cid);
588     pos += 2;
589     (*avrcp_callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
590 }
591 
592 uint16_t avrcp_sdp_query_browsing_l2cap_psm(void){
593     return avrcp_sdp_query_context.browsing_l2cap_psm;
594 }
595 
596 void avrcp_handle_sdp_client_query_attribute_value(uint8_t *packet){
597     des_iterator_t des_list_it;
598     des_iterator_t prot_it;
599 
600     // Handle new SDP record
601     if (sdp_event_query_attribute_byte_get_record_id(packet) != avrcp_sdp_query_context.record_id) {
602         avrcp_sdp_query_context.record_id = sdp_event_query_attribute_byte_get_record_id(packet);
603         avrcp_sdp_query_context.parse_sdp_record = 0;
604         // log_info("SDP Record: Nr: %d", record_id);
605     }
606 
607     if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= avrcp_sdp_query_attribute_value_buffer_size) {
608         avrcp_sdp_query_attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
609 
610         if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
611             switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
612                 case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
613                     if (de_get_element_type(avrcp_sdp_query_attribute_value) != DE_DES) break;
614                     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)) {
615                         uint8_t * element = des_iterator_get_element(&des_list_it);
616                         if (de_get_element_type(element) != DE_UUID) continue;
617                         uint32_t uuid = de_get_uuid32(element);
618                         switch (uuid){
619                             case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_TARGET:
620                             case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL:
621                             case BLUETOOTH_SERVICE_CLASS_AV_REMOTE_CONTROL_CONTROLLER:
622                                 avrcp_sdp_query_context.parse_sdp_record = 1;
623                                 break;
624                             default:
625                                 break;
626                         }
627                     }
628                     break;
629 
630                 case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
631                     if (!avrcp_sdp_query_context.parse_sdp_record) break;
632                     // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
633                     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)) {
634                         uint8_t       *des_element;
635                         uint8_t       *element;
636                         uint32_t       uuid;
637 
638                         if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
639 
640                         des_element = des_iterator_get_element(&des_list_it);
641                         des_iterator_init(&prot_it, des_element);
642                         element = des_iterator_get_element(&prot_it);
643 
644                         if (de_get_element_type(element) != DE_UUID) continue;
645 
646                         uuid = de_get_uuid32(element);
647                         des_iterator_next(&prot_it);
648                         switch (uuid){
649                             case BLUETOOTH_PROTOCOL_L2CAP:
650                                 if (!des_iterator_has_more(&prot_it)) continue;
651                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &avrcp_sdp_query_context.avrcp_l2cap_psm);
652                                 break;
653                             case BLUETOOTH_PROTOCOL_AVCTP:
654                                 if (!des_iterator_has_more(&prot_it)) continue;
655                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &avrcp_sdp_query_context.avrcp_version);
656                                 break;
657                             default:
658                                 break;
659                         }
660                     }
661                 }
662                     break;
663                 case BLUETOOTH_ATTRIBUTE_ADDITIONAL_PROTOCOL_DESCRIPTOR_LISTS: {
664                     // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
665                     if (!avrcp_sdp_query_context.parse_sdp_record) break;
666                     if (de_get_element_type(avrcp_sdp_query_attribute_value) != DE_DES) break;
667 
668                     des_iterator_t des_list_0_it;
669                     uint8_t       *element_0;
670 
671                     des_iterator_init(&des_list_0_it, avrcp_sdp_query_attribute_value);
672                     element_0 = des_iterator_get_element(&des_list_0_it);
673 
674                     for (des_iterator_init(&des_list_it, element_0); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
675                         uint8_t       *des_element;
676                         uint8_t       *element;
677                         uint32_t       uuid;
678 
679                         if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
680 
681                         des_element = des_iterator_get_element(&des_list_it);
682                         des_iterator_init(&prot_it, des_element);
683                         element = des_iterator_get_element(&prot_it);
684 
685                         if (de_get_element_type(element) != DE_UUID) continue;
686 
687                         uuid = de_get_uuid32(element);
688                         des_iterator_next(&prot_it);
689                         switch (uuid){
690                             case BLUETOOTH_PROTOCOL_L2CAP:
691                                 if (!des_iterator_has_more(&prot_it)) continue;
692                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &avrcp_sdp_query_context.browsing_l2cap_psm);
693                                 break;
694                             case BLUETOOTH_PROTOCOL_AVCTP:
695                                 if (!des_iterator_has_more(&prot_it)) continue;
696                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &avrcp_sdp_query_context.browsing_version);
697                                 break;
698                             default:
699                                 break;
700                         }
701                     }
702                 }
703                     break;
704                 default:
705                     break;
706             }
707         }
708     } else {
709         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));
710     }
711 }
712 
713 static void avrcp_handle_sdp_query_failed(avrcp_connection_t * connection, uint8_t status){
714     if (connection == NULL) return;
715     log_info("AVRCP: SDP query failed with status 0x%02x.", status);
716     avrcp_emit_connection_established(connection->avrcp_cid, connection->remote_addr, connection->con_handle, status);
717     avrcp_finalize_connection(connection);
718 }
719 
720 static void avrcp_handle_sdp_query_succeeded(avrcp_connection_t * connection){
721     if (connection == NULL) return;
722     connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
723     connection->avrcp_l2cap_psm = avrcp_sdp_query_context.avrcp_l2cap_psm;
724     connection->browsing_version = avrcp_sdp_query_context.browsing_version;
725     connection->browsing_l2cap_psm = avrcp_sdp_query_context.browsing_l2cap_psm;
726 }
727 
728 static void avrcp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
729     UNUSED(packet_type);
730     UNUSED(channel);
731     UNUSED(size);
732 
733     bool state_ok = true;
734     avrcp_connection_t * avrcp_target_connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_sdp_query_context.avrcp_cid);
735     if (!avrcp_target_connection || avrcp_target_connection->state != AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE) {
736         state_ok = false;
737     }
738     avrcp_connection_t * avrcp_controller_connection = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_sdp_query_context.avrcp_cid);
739     if (!avrcp_controller_connection || avrcp_controller_connection->state != AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE) {
740         state_ok = false;
741     }
742     if (!state_ok){
743         // something wrong, nevertheless, start next sdp query if this one is complete
744         if (hci_event_packet_get_type(packet) == SDP_EVENT_QUERY_COMPLETE){
745             (void) sdp_client_register_query_callback(&avrcp_sdp_query_registration);
746         }
747         return;
748     }
749 
750     uint8_t status;
751 
752     switch (hci_event_packet_get_type(packet)){
753         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
754             avrcp_handle_sdp_client_query_attribute_value(packet);
755             return;
756 
757         case SDP_EVENT_QUERY_COMPLETE:
758             status = sdp_event_query_complete_get_status(packet);
759 
760             if (status != ERROR_CODE_SUCCESS){
761                 avrcp_handle_sdp_query_failed(avrcp_controller_connection, status);
762                 avrcp_handle_sdp_query_failed(avrcp_target_connection, status);
763                 break;
764             }
765 
766             if (!avrcp_sdp_query_context.avrcp_l2cap_psm){
767                 avrcp_handle_sdp_query_failed(avrcp_controller_connection, SDP_SERVICE_NOT_FOUND);
768                 avrcp_handle_sdp_query_failed(avrcp_target_connection, SDP_SERVICE_NOT_FOUND);
769                 break;
770             }
771 
772             avrcp_handle_sdp_query_succeeded(avrcp_controller_connection);
773             avrcp_handle_sdp_query_succeeded(avrcp_target_connection);
774 
775             l2cap_create_channel(&avrcp_packet_handler, avrcp_target_connection->remote_addr, avrcp_sdp_query_context.avrcp_l2cap_psm, l2cap_max_mtu(), NULL);
776             break;
777 
778         default:
779             return;
780     }
781 
782     // register the SDP Query request to check if there is another connection waiting for the query
783     // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
784     (void) sdp_client_register_query_callback(&avrcp_sdp_query_registration);
785 }
786 
787 
788 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){
789     if (connection == NULL){
790         connection = avrcp_create_connection(role, event_addr);
791     }
792     if (connection) {
793         connection->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
794         connection->l2cap_signaling_cid = local_cid;
795         connection->avrcp_cid = avrcp_cid;
796         connection->con_handle = con_handle;
797         btstack_run_loop_remove_timer(&connection->retry_timer);
798     }
799     return connection;
800 }
801 
802 static void avrcp_handle_open_connection(avrcp_connection_t * connection, hci_con_handle_t con_handle, uint16_t local_cid, uint16_t l2cap_mtu){
803     connection->l2cap_signaling_cid = local_cid;
804     connection->l2cap_mtu = l2cap_mtu;
805     connection->con_handle = con_handle;
806     connection->incoming_declined = false;
807     connection->target_song_length_ms = 0xFFFFFFFF;
808     connection->target_song_position_ms = 0xFFFFFFFF;
809     memset(connection->target_track_id, 0xFF, 8);
810     connection->target_track_selected = false;
811     connection->target_playback_status = AVRCP_PLAYBACK_STATUS_STOPPED;
812     connection->state = AVCTP_CONNECTION_OPENED;
813 
814     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);
815 }
816 
817 static void avrcp_retry_timer_timeout_handler(btstack_timer_source_t * timer){
818     uint16_t avrcp_cid = (uint16_t)(uintptr_t) btstack_run_loop_get_timer_context(timer);
819     avrcp_connection_t * connection_controller = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
820     if (connection_controller == NULL) return;
821     avrcp_connection_t * connection_target = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
822     if (connection_target == NULL) return;
823 
824     if (connection_controller->state == AVCTP_CONNECTION_W2_L2CAP_RETRY){
825         connection_controller->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
826         connection_target->state = AVCTP_CONNECTION_W4_L2CAP_CONNECTED;
827         l2cap_create_channel(&avrcp_packet_handler, connection_controller->remote_addr, connection_controller->avrcp_l2cap_psm, l2cap_max_mtu(), NULL);
828     }
829 }
830 
831 static void avrcp_retry_timer_start(avrcp_connection_t * connection){
832     btstack_run_loop_set_timer_handler(&connection->retry_timer, avrcp_retry_timer_timeout_handler);
833     btstack_run_loop_set_timer_context(&connection->retry_timer, (void *)(uintptr_t)connection->avrcp_cid);
834 
835     // add some jitter/randomness to reconnect delay
836     uint32_t timeout = 100 + (btstack_run_loop_get_time_ms() & 0x7F);
837     btstack_run_loop_set_timer(&connection->retry_timer, timeout);
838 
839     btstack_run_loop_add_timer(&connection->retry_timer);
840 }
841 
842 static avrcp_frame_type_t avrcp_get_frame_type(uint8_t header){
843     return (avrcp_frame_type_t)((header & 0x02) >> 1);
844 }
845 
846 static void avrcp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
847     UNUSED(channel);
848     UNUSED(size);
849     bd_addr_t event_addr;
850     uint16_t local_cid;
851     uint16_t l2cap_mtu;
852     uint8_t  status;
853     bool decline_connection;
854     bool outoing_active;
855     hci_con_handle_t con_handle;
856 
857     avrcp_connection_t * connection_controller;
858     avrcp_connection_t * connection_target;
859     bool can_send;
860 
861     switch (packet_type) {
862         case HCI_EVENT_PACKET:
863             switch (hci_event_packet_get_type(packet)) {
864 
865                 case L2CAP_EVENT_INCOMING_CONNECTION:
866                     btstack_assert(avrcp_controller_packet_handler != NULL);
867                     btstack_assert(avrcp_target_packet_handler != NULL);
868 
869                     l2cap_event_incoming_connection_get_address(packet, event_addr);
870                     local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
871                     con_handle = l2cap_event_incoming_connection_get_handle(packet);
872 
873                     outoing_active = false;
874                     connection_target = avrcp_get_connection_for_bd_addr_for_role(AVRCP_TARGET, event_addr);
875                     if (connection_target != NULL){
876                         if (connection_target->state == AVCTP_CONNECTION_W4_L2CAP_CONNECTED){
877                             outoing_active = true;
878                             connection_target->incoming_declined = true;
879                         }
880                     }
881 
882                     connection_controller = avrcp_get_connection_for_bd_addr_for_role(AVRCP_CONTROLLER, event_addr);
883                     if (connection_controller != NULL){
884                         if (connection_controller->state == AVCTP_CONNECTION_W4_L2CAP_CONNECTED) {
885                             outoing_active = true;
886                             connection_controller->incoming_declined = true;
887                         }
888                     }
889 
890                     decline_connection = outoing_active;
891                     if (decline_connection == false){
892                         uint16_t avrcp_cid;
893                         if ((connection_controller == NULL) || (connection_target == NULL)){
894                             avrcp_cid = avrcp_get_next_cid(AVRCP_CONTROLLER);
895                         } else {
896                             avrcp_cid = connection_controller->avrcp_cid;
897                         }
898                         // create two connection objects (both)
899                         connection_target     = avrcp_handle_incoming_connection_for_role(AVRCP_TARGET, connection_target, event_addr, con_handle, local_cid, avrcp_cid);
900                         connection_controller = avrcp_handle_incoming_connection_for_role(AVRCP_CONTROLLER, connection_controller, event_addr, con_handle, local_cid, avrcp_cid);
901                         if ((connection_target == NULL) || (connection_controller == NULL)){
902                             decline_connection = true;
903                             if (connection_target) {
904                                 avrcp_finalize_connection(connection_target);
905                             }
906                             if (connection_controller) {
907                                 avrcp_finalize_connection(connection_controller);
908                             }
909                         }
910                     }
911                     if (decline_connection){
912                         l2cap_decline_connection(local_cid);
913                     } else {
914                         log_info("AVRCP: L2CAP_EVENT_INCOMING_CONNECTION local cid 0x%02x, state %d", local_cid, connection_controller->state);
915                         l2cap_accept_connection(local_cid);
916                     }
917                     break;
918 
919                 case L2CAP_EVENT_CHANNEL_OPENED:
920                     l2cap_event_channel_opened_get_address(packet, event_addr);
921                     status = l2cap_event_channel_opened_get_status(packet);
922                     local_cid = l2cap_event_channel_opened_get_local_cid(packet);
923                     l2cap_mtu = l2cap_event_channel_opened_get_remote_mtu(packet);
924                     con_handle = l2cap_event_channel_opened_get_handle(packet);
925 
926                     connection_controller = avrcp_get_connection_for_bd_addr_for_role(AVRCP_CONTROLLER, event_addr);
927                     connection_target = avrcp_get_connection_for_bd_addr_for_role(AVRCP_TARGET, event_addr);
928 
929                     // incoming: structs are already created in L2CAP_EVENT_INCOMING_CONNECTION
930                     // outgoing: structs are cteated in avrcp_connect()
931                     if ((connection_controller == NULL) || (connection_target == NULL)) {
932                         break;
933                     }
934 
935                     switch (status){
936                         case ERROR_CODE_SUCCESS:
937                             avrcp_handle_open_connection(connection_target, con_handle, local_cid, l2cap_mtu);
938                             avrcp_handle_open_connection(connection_controller, con_handle, local_cid, l2cap_mtu);
939                             avrcp_emit_connection_established(connection_controller->avrcp_cid, event_addr, con_handle, status);
940                             return;
941                         case L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_RESOURCES:
942                             if (connection_controller->incoming_declined == true){
943                                 log_info("Incoming connection was declined, and the outgoing failed");
944                                 connection_controller->state = AVCTP_CONNECTION_W2_L2CAP_RETRY;
945                                 connection_controller->incoming_declined = false;
946                                 connection_target->state = AVCTP_CONNECTION_W2_L2CAP_RETRY;
947                                 connection_target->incoming_declined = false;
948                                 avrcp_retry_timer_start(connection_controller);
949                                 return;
950                             }
951                             break;
952                         default:
953                             break;
954                     }
955                     log_info("L2CAP connection to connection %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
956                     avrcp_emit_connection_established(connection_controller->avrcp_cid, event_addr, con_handle, status);
957                     avrcp_finalize_connection(connection_controller);
958                     avrcp_finalize_connection(connection_target);
959 
960                     break;
961 
962                 case L2CAP_EVENT_CHANNEL_CLOSED:
963                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
964 
965                     connection_controller = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, local_cid);
966                     connection_target = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, local_cid);
967                     if ((connection_controller == NULL) || (connection_target == NULL)) {
968                         break;
969                     }
970                     avrcp_emit_connection_closed(connection_controller->avrcp_cid);
971                     avrcp_finalize_connection(connection_controller);
972                     avrcp_finalize_connection(connection_target);
973                     break;
974 
975                 case L2CAP_EVENT_CAN_SEND_NOW:
976                     local_cid = l2cap_event_can_send_now_get_local_cid(packet);
977                     can_send = true;
978 
979                     connection_target = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_TARGET, local_cid);
980                     if ((connection_target != NULL) && connection_target->wait_to_send){
981                         connection_target->wait_to_send = false;
982                         (*avrcp_target_packet_handler)(HCI_EVENT_PACKET, channel, packet, size);
983                         can_send = false;
984                     }
985 
986                     connection_controller = avrcp_get_connection_for_l2cap_signaling_cid_for_role(AVRCP_CONTROLLER, local_cid);
987                     if ((connection_controller != NULL) && connection_controller->wait_to_send){
988                         if (can_send){
989                             connection_controller->wait_to_send = false;
990                             (*avrcp_controller_packet_handler)(HCI_EVENT_PACKET, channel, packet, size);
991                         } else {
992                             l2cap_request_can_send_now_event(local_cid);
993                         }
994                     }
995                     break;
996 
997                 default:
998                     break;
999             }
1000             break;
1001 
1002         case L2CAP_DATA_PACKET:
1003             switch (avrcp_get_frame_type(packet[0])){
1004                 case AVRCP_RESPONSE_FRAME:
1005                     (*avrcp_controller_packet_handler)(packet_type, channel, packet, size);
1006                     break;
1007                 case AVRCP_COMMAND_FRAME:
1008                 default:    // make compiler happy
1009                     (*avrcp_target_packet_handler)(packet_type, channel, packet, size);
1010                     break;
1011             }
1012             break;
1013 
1014         default:
1015             break;
1016     }
1017 }
1018 
1019 uint8_t avrcp_disconnect(uint16_t avrcp_cid){
1020     avrcp_connection_t * connection_controller = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, avrcp_cid);
1021     if (!connection_controller){
1022         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1023     }
1024     avrcp_connection_t * connection_target = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, avrcp_cid);
1025     if (!connection_target){
1026         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1027     }
1028     if (connection_controller->browsing_connection){
1029         l2cap_disconnect(connection_controller->browsing_connection->l2cap_browsing_cid);
1030     }
1031     l2cap_disconnect(connection_controller->l2cap_signaling_cid);
1032     return ERROR_CODE_SUCCESS;
1033 }
1034 
1035 static void avrcp_handle_start_sdp_client_query(void * context){
1036     UNUSED(context);
1037 
1038     btstack_linked_list_iterator_t it;
1039     btstack_linked_list_iterator_init(&it, &avrcp_connections);
1040     while (btstack_linked_list_iterator_has_next(&it)){
1041         avrcp_connection_t * connection = (avrcp_connection_t *)btstack_linked_list_iterator_next(&it);
1042 
1043         if (connection->state != AVCTP_CONNECTION_W2_SEND_SDP_QUERY) continue;
1044         connection->state = AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE;
1045 
1046         // prevent triggering SDP query twice (for each role once)
1047         avrcp_connection_t * connection_with_opposite_role;
1048         switch (connection->role){
1049             case AVRCP_CONTROLLER:
1050                 connection_with_opposite_role = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_TARGET, connection->avrcp_cid);
1051                 break;
1052             case AVRCP_TARGET:
1053                 connection_with_opposite_role = avrcp_get_connection_for_avrcp_cid_for_role(AVRCP_CONTROLLER, connection->avrcp_cid);
1054                 break;
1055             default:
1056                 btstack_assert(false);
1057                 return;
1058         }
1059         connection_with_opposite_role->state = AVCTP_CONNECTION_W4_SDP_QUERY_COMPLETE;
1060 
1061         avrcp_sdp_query_context.avrcp_l2cap_psm = 0;
1062         avrcp_sdp_query_context.avrcp_version  = 0;
1063         avrcp_sdp_query_context.avrcp_cid = connection->avrcp_cid;
1064         sdp_client_query_uuid16(&avrcp_handle_sdp_client_query_result, (uint8_t *) connection->remote_addr, BLUETOOTH_PROTOCOL_AVCTP);
1065         return;
1066     }
1067 }
1068 
1069 uint8_t avrcp_connect(bd_addr_t remote_addr, uint16_t * avrcp_cid){
1070     btstack_assert(avrcp_controller_packet_handler != NULL);
1071     btstack_assert(avrcp_target_packet_handler != NULL);
1072 
1073     avrcp_connection_t * connection_controller = avrcp_get_connection_for_bd_addr_for_role(AVRCP_CONTROLLER, remote_addr);
1074     if (connection_controller){
1075         return ERROR_CODE_COMMAND_DISALLOWED;
1076     }
1077     avrcp_connection_t * connection_target = avrcp_get_connection_for_bd_addr_for_role(AVRCP_TARGET, remote_addr);
1078     if (connection_target){
1079         return ERROR_CODE_COMMAND_DISALLOWED;
1080     }
1081 
1082     uint16_t cid = avrcp_get_next_cid(AVRCP_CONTROLLER);
1083 
1084     connection_controller = avrcp_create_connection(AVRCP_CONTROLLER, remote_addr);
1085     if (!connection_controller) return BTSTACK_MEMORY_ALLOC_FAILED;
1086 
1087     connection_target = avrcp_create_connection(AVRCP_TARGET, remote_addr);
1088     if (!connection_target){
1089         avrcp_finalize_connection(connection_controller);
1090         return BTSTACK_MEMORY_ALLOC_FAILED;
1091     }
1092 
1093     if (avrcp_cid != NULL){
1094         *avrcp_cid = cid;
1095     }
1096 
1097     connection_controller->state = AVCTP_CONNECTION_W2_SEND_SDP_QUERY;
1098     connection_controller->avrcp_cid = cid;
1099 
1100     connection_target->state     = AVCTP_CONNECTION_W2_SEND_SDP_QUERY;
1101     connection_target->avrcp_cid = cid;
1102 
1103     avrcp_sdp_query_registration.callback = &avrcp_handle_start_sdp_client_query;
1104     // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
1105     (void) sdp_client_register_query_callback(&avrcp_sdp_query_registration);
1106     return ERROR_CODE_SUCCESS;
1107 }
1108 
1109 void avrcp_init(void){
1110     avrcp_connections = NULL;
1111     if (avrcp_l2cap_service_registered) return;
1112 
1113     int status = l2cap_register_service(&avrcp_packet_handler, BLUETOOTH_PSM_AVCTP, 0xffff, gap_get_security_level());
1114     if (status != ERROR_CODE_SUCCESS) return;
1115     avrcp_l2cap_service_registered = true;
1116 }
1117 
1118 void avrcp_deinit(void){
1119     avrcp_l2cap_service_registered = false;
1120 
1121     avrcp_cid_counter = 0;
1122     avrcp_connections = NULL;
1123 
1124     avrcp_callback = NULL;
1125     avrcp_controller_packet_handler = NULL;
1126     avrcp_target_packet_handler = NULL;
1127 
1128     (void) memset(&avrcp_sdp_query_registration, 0, sizeof(avrcp_sdp_query_registration));
1129     (void) memset(&avrcp_sdp_query_context, 0, sizeof(avrcp_sdp_query_context_t));
1130     (void) memset(avrcp_sdp_query_attribute_value, 0, sizeof(avrcp_sdp_query_attribute_value));
1131 }
1132 
1133 void avrcp_register_controller_packet_handler(btstack_packet_handler_t callback){
1134     avrcp_controller_packet_handler = callback;
1135 }
1136 
1137 void avrcp_register_target_packet_handler(btstack_packet_handler_t callback){
1138     avrcp_target_packet_handler = callback;
1139 }
1140 
1141 void avrcp_register_packet_handler(btstack_packet_handler_t callback){
1142     btstack_assert(callback != NULL);
1143     avrcp_callback = callback;
1144 }
1145 
1146 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
1147 #define FUZZ_CID 0x44
1148 #define FUZZ_CON_HANDLE 0x0001
1149 static bd_addr_t remote_addr = { 0x33, 0x33, 0x33, 0x33, 0x33, 0x33 };
1150 void avrcp_init_fuzz(void){
1151     // setup avrcp connections for cid
1152     avrcp_connection_t * connection_controller = avrcp_create_connection(AVRCP_CONTROLLER, remote_addr);
1153     avrcp_connection_t * connection_target     = avrcp_create_connection(AVRCP_TARGET, remote_addr);
1154     avrcp_handle_open_connection(connection_controller, FUZZ_CON_HANDLE, FUZZ_CID, 999);
1155     avrcp_handle_open_connection(connection_target, FUZZ_CON_HANDLE, FUZZ_CID, 999);
1156 }
1157 void avrcp_packet_handler_fuzz(uint8_t *packet, uint16_t size){
1158     avrcp_packet_handler(L2CAP_DATA_PACKET, FUZZ_CID, packet, size);
1159 }
1160 #endif