xref: /btstack/src/classic/avdtp.c (revision f2eb0907497ae6c49729a66e13ab73e9da185656)
1 /*
2  * Copyright (C) 2016 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define BTSTACK_FILE__ "avdtp.c"
39 
40 
41 #include <stdint.h>
42 #include <string.h>
43 
44 #include "bluetooth_psm.h"
45 #include "bluetooth_sdp.h"
46 #include "btstack_debug.h"
47 #include "btstack_event.h"
48 #include "btstack_memory.h"
49 #include "classic/avdtp.h"
50 #include "classic/avdtp_acceptor.h"
51 #include "classic/avdtp_initiator.h"
52 #include "classic/avdtp_util.h"
53 #include "classic/sdp_client.h"
54 #include "classic/sdp_util.h"
55 
56 btstack_linked_list_t stream_endpoints;
57 
58 static btstack_packet_handler_t avdtp_source_callback;
59 static btstack_packet_handler_t avdtp_sink_callback;
60 static btstack_context_callback_registration_t avdtp_handle_sdp_client_query_request;
61 
62 static uint16_t sdp_query_context_avdtp_cid = 0;
63 
64 static uint16_t stream_endpoints_id_counter = 0;
65 
66 static btstack_linked_list_t connections;
67 static uint16_t transaction_id_counter = 0;
68 
69 static int record_id = -1;
70 static uint8_t   attribute_value[45];
71 static const unsigned int attribute_value_buffer_size = sizeof(attribute_value);
72 
73 static void (*avdtp_sink_handle_media_data)(uint8_t local_seid, uint8_t *packet, uint16_t size);
74 
75 static uint16_t avdtp_cid_counter = 0;
76 
77 static void avdtp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
78 
79 btstack_packet_handler_t
80 avdtp_packet_handler_for_stream_endpoint(const avdtp_stream_endpoint_t *stream_endpoint) {
81     return (stream_endpoint->sep.type == AVDTP_SOURCE) ? avdtp_source_callback : avdtp_sink_callback;
82 }
83 
84 void avdtp_emit_sink_and_source(uint8_t * packet, uint16_t size){
85     if (avdtp_source_callback != NULL){
86         (*avdtp_source_callback)(HCI_EVENT_PACKET, 0, packet, size);
87     }
88     if (avdtp_sink_callback != NULL){
89         (*avdtp_sink_callback)(HCI_EVENT_PACKET, 0, packet, size);
90     }
91 }
92 
93 void avdtp_emit_source(uint8_t * packet, uint16_t size){
94     if (avdtp_source_callback != NULL){
95         (*avdtp_source_callback)(HCI_EVENT_PACKET, 0, packet, size);
96     }
97 }
98 
99 btstack_linked_list_t * avdtp_get_stream_endpoints(void){
100     return &stream_endpoints;
101 }
102 
103 btstack_linked_list_t * avdtp_get_connections(void){
104     return &connections;
105 }
106 
107 static avdtp_connection_t * avdtp_get_connection_for_bd_addr(bd_addr_t addr){
108     btstack_linked_list_iterator_t it;
109     btstack_linked_list_iterator_init(&it, &connections);
110     while (btstack_linked_list_iterator_has_next(&it)){
111         avdtp_connection_t * connection = (avdtp_connection_t *)btstack_linked_list_iterator_next(&it);
112         if (memcmp(addr, connection->remote_addr, 6) != 0) continue;
113         return connection;
114     }
115     return NULL;
116 }
117 
118  avdtp_connection_t * avdtp_get_connection_for_avdtp_cid(uint16_t avdtp_cid){
119     btstack_linked_list_iterator_t it;
120     btstack_linked_list_iterator_init(&it, &connections);
121     while (btstack_linked_list_iterator_has_next(&it)){
122         avdtp_connection_t * connection = (avdtp_connection_t *)btstack_linked_list_iterator_next(&it);
123         if (connection->avdtp_cid != avdtp_cid) continue;
124         return connection;
125     }
126     return NULL;
127 }
128 
129 
130 avdtp_stream_endpoint_t * avdtp_get_stream_endpoint_for_seid(uint16_t seid){
131     btstack_linked_list_iterator_t it;
132     btstack_linked_list_iterator_init(&it, avdtp_get_stream_endpoints());
133     while (btstack_linked_list_iterator_has_next(&it)){
134         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
135         if (stream_endpoint->sep.seid == seid){
136             return stream_endpoint;
137         }
138     }
139     return NULL;
140 }
141 
142 avdtp_connection_t * avdtp_get_connection_for_l2cap_signaling_cid(uint16_t l2cap_cid){
143     btstack_linked_list_iterator_t it;
144     btstack_linked_list_iterator_init(&it, &connections);
145     while (btstack_linked_list_iterator_has_next(&it)){
146         avdtp_connection_t * connection = (avdtp_connection_t *)btstack_linked_list_iterator_next(&it);
147         if (connection->l2cap_signaling_cid != l2cap_cid) continue;
148         return connection;
149     }
150     return NULL;
151 }
152 
153 static avdtp_stream_endpoint_t * avdtp_get_stream_endpoint_for_l2cap_cid(uint16_t l2cap_cid){
154     btstack_linked_list_iterator_t it;
155     btstack_linked_list_iterator_init(&it, avdtp_get_stream_endpoints());
156     while (btstack_linked_list_iterator_has_next(&it)){
157         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
158         if (stream_endpoint->l2cap_media_cid == l2cap_cid){
159             return stream_endpoint;
160         }
161         if (stream_endpoint->l2cap_reporting_cid == l2cap_cid){
162             return stream_endpoint;
163         }
164         if (stream_endpoint->l2cap_recovery_cid == l2cap_cid){
165             return stream_endpoint;
166         }
167     }
168     return NULL;
169 }
170 
171 static avdtp_stream_endpoint_t * avdtp_get_stream_endpoint_for_signaling_cid(uint16_t l2cap_cid){
172     btstack_linked_list_iterator_t it;
173     btstack_linked_list_iterator_init(&it, avdtp_get_stream_endpoints());
174     while (btstack_linked_list_iterator_has_next(&it)){
175         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
176         if (stream_endpoint->connection){
177             if (stream_endpoint->connection->l2cap_signaling_cid == l2cap_cid){
178                 return stream_endpoint;
179             }
180         }
181     }
182     return NULL;
183 }
184 
185 avdtp_stream_endpoint_t * avdtp_get_stream_endpoint_with_seid(uint8_t seid){
186     btstack_linked_list_iterator_t it;
187     btstack_linked_list_iterator_init(&it, avdtp_get_stream_endpoints());
188     while (btstack_linked_list_iterator_has_next(&it)){
189         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
190         if (stream_endpoint->sep.seid == seid){
191             return stream_endpoint;
192         }
193     }
194     return NULL;
195 }
196 
197 avdtp_stream_endpoint_t * avdtp_get_stream_endpoint_associated_with_acp_seid(uint16_t acp_seid){
198     btstack_linked_list_iterator_t it;
199     btstack_linked_list_iterator_init(&it, avdtp_get_stream_endpoints());
200     while (btstack_linked_list_iterator_has_next(&it)){
201         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
202         if (stream_endpoint->remote_sep.seid == acp_seid){
203             return stream_endpoint;
204         }
205     }
206     return NULL;
207 }
208 
209 uint16_t avdtp_get_next_transaction_label(void){
210     transaction_id_counter++;
211     if (transaction_id_counter == 16){
212         transaction_id_counter = 1;
213     }
214     return transaction_id_counter;
215 }
216 
217 static avdtp_connection_t * avdtp_create_connection(bd_addr_t remote_addr, uint16_t cid){
218     avdtp_connection_t * connection = btstack_memory_avdtp_connection_get();
219     if (!connection){
220         log_error("Not enough memory to create connection");
221         return NULL;
222     }
223     connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
224     connection->initiator_transaction_label = avdtp_get_next_transaction_label();
225     connection->configuration_state = AVDTP_CONFIGURATION_STATE_IDLE;
226     connection->a2dp_source_discover_seps = false;
227     connection->avdtp_cid = cid;
228     (void)memcpy(connection->remote_addr, remote_addr, 6);
229 
230     btstack_linked_list_add(&connections, (btstack_linked_item_t *) connection);
231     return connection;
232 }
233 
234 static uint16_t avdtp_get_next_cid(void){
235     if (avdtp_cid_counter == 0xffff) {
236         avdtp_cid_counter = 1;
237     } else {
238         avdtp_cid_counter++;
239     }
240     return avdtp_cid_counter;
241 }
242 
243 static uint16_t avdtp_get_next_local_seid(void){
244     if (stream_endpoints_id_counter == 0xffff) {
245         stream_endpoints_id_counter = 1;
246     } else {
247         stream_endpoints_id_counter++;
248     }
249     return stream_endpoints_id_counter;
250 }
251 
252 static void avdtp_handle_start_sdp_client_query(void * context){
253     UNUSED(context);
254 
255     btstack_linked_list_iterator_t it;
256     btstack_linked_list_iterator_init(&it, &connections);
257     while (btstack_linked_list_iterator_has_next(&it)){
258         avdtp_connection_t * connection = (avdtp_connection_t *)btstack_linked_list_iterator_next(&it);
259 
260         switch (connection->state){
261             case AVDTP_SIGNALING_W2_SEND_SDP_QUERY_FOR_REMOTE_SOURCE:
262                 connection->state = AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SOURCE_COMPLETE;
263                 break;
264             case AVDTP_SIGNALING_W2_SEND_SDP_QUERY_FOR_REMOTE_SINK:
265                 connection->state = AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SINK_COMPLETE;
266                 break;
267             default:
268                 continue;
269         }
270         sdp_query_context_avdtp_cid = connection->avdtp_cid;
271         sdp_client_query_uuid16(&avdtp_handle_sdp_client_query_result, (uint8_t *) connection->remote_addr, BLUETOOTH_PROTOCOL_AVDTP);
272         return;
273     }
274 }
275 
276 uint8_t avdtp_connect(bd_addr_t remote, avdtp_role_t role, uint16_t * avdtp_cid){
277     avdtp_connection_t * connection = avdtp_get_connection_for_bd_addr(remote);
278     if (connection){
279         return ERROR_CODE_COMMAND_DISALLOWED;
280     }
281 
282     uint16_t cid = avdtp_get_next_cid();
283     if (avdtp_cid != NULL) {
284         *avdtp_cid = cid;
285     }
286 
287     connection = avdtp_create_connection(remote, cid);
288     if (!connection) return BTSTACK_MEMORY_ALLOC_FAILED;
289 
290     connection->avdtp_cid = cid;
291 
292     connection->avdtp_l2cap_psm = 0;
293     connection->avdtp_version  = 0;
294     connection->sink_supported = false;
295     connection->source_supported = false;
296 
297     switch (role){
298         case AVDTP_ROLE_SOURCE:
299             connection->state = AVDTP_SIGNALING_W2_SEND_SDP_QUERY_FOR_REMOTE_SINK;
300             break;
301         case AVDTP_ROLE_SINK:
302             connection->state = AVDTP_SIGNALING_W2_SEND_SDP_QUERY_FOR_REMOTE_SOURCE;
303             break;
304         default:
305             btstack_assert(false);
306             return ERROR_CODE_COMMAND_DISALLOWED;
307     }
308 
309     avdtp_handle_sdp_client_query_request.callback = &avdtp_handle_start_sdp_client_query;
310     // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
311     (void) sdp_client_register_query_callback(&avdtp_handle_sdp_client_query_request);
312     return ERROR_CODE_SUCCESS;
313 }
314 
315 
316 void avdtp_register_sink_packet_handler(btstack_packet_handler_t callback){
317     btstack_assert(callback != NULL);
318     avdtp_sink_callback = callback;
319 }
320 
321 void avdtp_register_source_packet_handler(btstack_packet_handler_t callback){
322     btstack_assert(callback != NULL);
323     avdtp_source_callback = callback;
324 }
325 
326 void avdtp_register_media_transport_category(avdtp_stream_endpoint_t * stream_endpoint){
327     if (!stream_endpoint){
328         log_error("Stream endpoint with given seid is not registered.");
329         return;
330     }
331     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_TRANSPORT, 1);
332     stream_endpoint->sep.registered_service_categories = bitmap;
333 }
334 
335 void avdtp_register_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
336     if (!stream_endpoint){
337         log_error("Stream endpoint with given seid is not registered.");
338         return;
339     }
340     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_REPORTING, 1);
341     stream_endpoint->sep.registered_service_categories = bitmap;
342 }
343 
344 void avdtp_register_delay_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
345     if (!stream_endpoint){
346         log_error("Stream endpoint with given seid is not registered.");
347         return;
348     }
349     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_DELAY_REPORTING, 1);
350     stream_endpoint->sep.registered_service_categories = bitmap;
351 }
352 
353 void avdtp_register_recovery_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t maximum_recovery_window_size, uint8_t maximum_number_media_packets){
354     if (!stream_endpoint){
355         log_error("Stream endpoint with given seid is not registered.");
356         return;
357     }
358     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_RECOVERY, 1);
359     stream_endpoint->sep.registered_service_categories = bitmap;
360     stream_endpoint->sep.capabilities.recovery.recovery_type = 0x01; // 0x01 = RFC2733
361     stream_endpoint->sep.capabilities.recovery.maximum_recovery_window_size = maximum_recovery_window_size;
362     stream_endpoint->sep.capabilities.recovery.maximum_number_media_packets = maximum_number_media_packets;
363 }
364 
365 void avdtp_register_content_protection_category(avdtp_stream_endpoint_t * stream_endpoint, uint16_t cp_type, const uint8_t * cp_type_value, uint8_t cp_type_value_len){
366     if (!stream_endpoint){
367         log_error("Stream endpoint with given seid is not registered.");
368         return;
369     }
370     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_CONTENT_PROTECTION, 1);
371     stream_endpoint->sep.registered_service_categories = bitmap;
372     stream_endpoint->sep.capabilities.content_protection.cp_type = cp_type;
373     (void)memcpy(stream_endpoint->sep.capabilities.content_protection.cp_type_value,
374                  cp_type_value,
375                  btstack_min(cp_type_value_len, AVDTP_MAX_CONTENT_PROTECTION_TYPE_VALUE_LEN));
376     stream_endpoint->sep.capabilities.content_protection.cp_type_value_len = btstack_min(cp_type_value_len, AVDTP_MAX_CONTENT_PROTECTION_TYPE_VALUE_LEN);
377 }
378 
379 void avdtp_register_header_compression_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t back_ch, uint8_t media, uint8_t recovery){
380     if (!stream_endpoint){
381         log_error("Stream endpoint with given seid is not registered.");
382         return;
383     }
384     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_HEADER_COMPRESSION, 1);
385     stream_endpoint->sep.registered_service_categories = bitmap;
386     stream_endpoint->sep.capabilities.header_compression.back_ch = back_ch;
387     stream_endpoint->sep.capabilities.header_compression.media = media;
388     stream_endpoint->sep.capabilities.header_compression.recovery = recovery;
389 }
390 
391 void avdtp_register_media_codec_category(avdtp_stream_endpoint_t * stream_endpoint, avdtp_media_type_t media_type, avdtp_media_codec_type_t media_codec_type, uint8_t * media_codec_info, uint16_t media_codec_info_len){
392     if (!stream_endpoint){
393         log_error("Stream endpoint with given seid is not registered.");
394         return;
395     }
396     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_CODEC, 1);
397     stream_endpoint->sep.registered_service_categories = bitmap;
398     stream_endpoint->sep.capabilities.media_codec.media_type = media_type;
399     stream_endpoint->sep.capabilities.media_codec.media_codec_type = media_codec_type;
400     stream_endpoint->sep.capabilities.media_codec.media_codec_information = media_codec_info;
401     stream_endpoint->sep.capabilities.media_codec.media_codec_information_len = media_codec_info_len;
402 }
403 
404 void avdtp_register_multiplexing_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t fragmentation){
405     if (!stream_endpoint){
406         log_error("Stream endpoint with given seid is not registered.");
407         return;
408     }
409     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MULTIPLEXING, 1);
410     stream_endpoint->sep.registered_service_categories = bitmap;
411     stream_endpoint->sep.capabilities.multiplexing_mode.fragmentation = fragmentation;
412 }
413 
414 void avdtp_register_media_handler(void (*callback)(uint8_t local_seid, uint8_t *packet, uint16_t size)){
415     avdtp_sink_handle_media_data = callback;
416 }
417 
418 /* START: tracking can send now requests pro l2cap cid */
419 void avdtp_handle_can_send_now(avdtp_connection_t *connection, uint16_t l2cap_cid) {
420     if (connection->wait_to_send_acceptor){
421         log_debug("call avdtp_acceptor_stream_config_subsm_run");
422         connection->wait_to_send_acceptor = 0;
423         avdtp_acceptor_stream_config_subsm_run(connection);
424     } else if (connection->wait_to_send_initiator){
425         log_debug("call avdtp_initiator_stream_config_subsm_run");
426         connection->wait_to_send_initiator = 0;
427         avdtp_initiator_stream_config_subsm_run(connection);
428     }
429 
430     // re-register
431     bool more_to_send = connection->wait_to_send_acceptor || connection->wait_to_send_initiator;
432     log_debug("ask for more to send %d: acc-%d, ini-%d",  more_to_send, connection->wait_to_send_acceptor, connection->wait_to_send_initiator);
433 
434     if (more_to_send){
435         l2cap_request_can_send_now_event(l2cap_cid);
436     }
437 }
438 /* END: tracking can send now requests pro l2cap cid */
439 
440 
441 avdtp_stream_endpoint_t * avdtp_create_stream_endpoint(avdtp_sep_type_t sep_type, avdtp_media_type_t media_type){
442     avdtp_stream_endpoint_t * stream_endpoint = btstack_memory_avdtp_stream_endpoint_get();
443     if (!stream_endpoint){
444         log_error("Not enough memory to create stream endpoint");
445         return NULL;
446     }
447     stream_endpoint->sep.seid = avdtp_get_next_local_seid();
448     stream_endpoint->sep.media_type = media_type;
449     stream_endpoint->sep.type = sep_type;
450     btstack_linked_list_add(avdtp_get_stream_endpoints(), (btstack_linked_item_t *) stream_endpoint);
451     return stream_endpoint;
452 }
453 
454 void avdtp_finalize_stream_endpoint(avdtp_stream_endpoint_t * stream_endpoint){
455     btstack_linked_list_remove(avdtp_get_stream_endpoints(), (btstack_linked_item_t* ) stream_endpoint);
456     btstack_memory_avdtp_stream_endpoint_free(stream_endpoint);
457 }
458 
459 static void
460 handle_l2cap_data_packet_for_signaling_connection(avdtp_connection_t *connection, uint8_t *packet, uint16_t size) {
461     if (size < 2) return;
462 
463     uint16_t offset;
464     avdtp_message_type_t message_type = avdtp_get_signaling_packet_type(packet);
465     switch (message_type){
466         case AVDTP_CMD_MSG:
467             offset = avdtp_read_signaling_header(&connection->acceptor_signaling_packet, packet, size);
468             avdtp_acceptor_stream_config_subsm(connection, packet, size, offset);
469             break;
470         default:
471             offset = avdtp_read_signaling_header(&connection->initiator_signaling_packet, packet, size);
472             avdtp_initiator_stream_config_subsm(connection, packet, size, offset);
473             break;
474     }
475 }
476 
477 static void avdtp_handle_sdp_client_query_attribute_value(avdtp_connection_t * connection, uint8_t *packet){
478     des_iterator_t des_list_it;
479     des_iterator_t prot_it;
480 
481     // Handle new SDP record
482     if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id) {
483         record_id = sdp_event_query_attribute_byte_get_record_id(packet);
484         // log_info("SDP Record: Nr: %d", record_id);
485     }
486 
487     if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
488         attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
489 
490         if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
491 
492             switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
493 
494                 case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
495                     if (de_get_element_type(attribute_value) != DE_DES) break;
496                     for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
497                         uint8_t * element = des_iterator_get_element(&des_list_it);
498                         if (de_get_element_type(element) != DE_UUID) continue;
499                         uint32_t uuid = de_get_uuid32(element);
500                         switch (uuid){
501                             case BLUETOOTH_SERVICE_CLASS_AUDIO_SOURCE:
502                                 connection->source_supported = true;
503                                 log_info("source_supported");
504                                 break;
505                             case BLUETOOTH_SERVICE_CLASS_AUDIO_SINK:
506                                 connection->sink_supported = true;
507                                 log_info("sink_supported");
508                                 break;
509                             default:
510                                 break;
511                         }
512                     }
513                     break;
514 
515                 case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST:
516                     // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
517                     for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
518                         uint8_t       *des_element;
519                         uint8_t       *element;
520                         uint32_t       uuid;
521 
522                         if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
523 
524                         des_element = des_iterator_get_element(&des_list_it);
525                         des_iterator_init(&prot_it, des_element);
526                         element = des_iterator_get_element(&prot_it);
527 
528                         if (de_get_element_type(element) != DE_UUID) continue;
529 
530                         uuid = de_get_uuid32(element);
531                         des_iterator_next(&prot_it);
532                         // we assume that the even if there are both roles supported, remote device uses the same psm and avdtp version for both
533                         switch (uuid){
534                             case BLUETOOTH_PROTOCOL_L2CAP:
535                                 if (!des_iterator_has_more(&prot_it)) continue;
536                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->avdtp_l2cap_psm);
537                                 break;
538                             case BLUETOOTH_PROTOCOL_AVDTP:
539                                 if (!des_iterator_has_more(&prot_it)) continue;
540                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->avdtp_version);
541                                 break;
542                             default:
543                                 break;
544                         }
545                     }
546                     break;
547 
548                 default:
549                     break;
550             }
551         }
552     } else {
553         log_error("SDP attribute value buffer size exceeded: available %d, required %d", attribute_value_buffer_size, sdp_event_query_attribute_byte_get_attribute_length(packet));
554     }
555 
556 }
557 
558 static void avdtp_finalize_connection(avdtp_connection_t * connection){
559     btstack_run_loop_remove_timer(&connection->retry_timer);
560     btstack_linked_list_remove(&connections, (btstack_linked_item_t*) connection);
561     btstack_memory_avdtp_connection_free(connection);
562 }
563 
564 static void avdtp_handle_sdp_query_failed(avdtp_connection_t * connection, uint8_t status){
565     switch (connection->state){
566         case AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SINK_COMPLETE:
567             avdtp_signaling_emit_connection_established(connection->avdtp_cid, connection->remote_addr, status);
568             break;
569         case AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SOURCE_COMPLETE:
570             avdtp_signaling_emit_connection_established(connection->avdtp_cid, connection->remote_addr, status);
571             break;
572         default:
573             return;
574     }
575     avdtp_finalize_connection(connection);
576     sdp_query_context_avdtp_cid = 0;
577     log_info("SDP query failed with status 0x%02x.", status);
578 }
579 
580 static void avdtp_handle_sdp_query_succeeded(avdtp_connection_t * connection){
581     connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
582 }
583 
584 static void avdtp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
585     UNUSED(packet_type);
586     UNUSED(channel);
587     UNUSED(size);
588 
589     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(sdp_query_context_avdtp_cid);
590     if (!connection) {
591         log_error("SDP query, connection with 0x%02x cid not found", sdp_query_context_avdtp_cid);
592         return;
593     }
594 
595     uint8_t status = ERROR_CODE_SUCCESS;
596     switch (connection->state){
597         case AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SINK_COMPLETE:
598             switch (hci_event_packet_get_type(packet)){
599                 case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
600                     avdtp_handle_sdp_client_query_attribute_value(connection, packet);
601                     return;
602                 case SDP_EVENT_QUERY_COMPLETE:
603                     status = sdp_event_query_complete_get_status(packet);
604                     if (status != ERROR_CODE_SUCCESS) break;
605                     if (!connection->sink_supported) {
606                         status = ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
607                         break;
608                     }
609                     if (connection->avdtp_l2cap_psm == 0) {
610                         status = ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
611                         break;
612                     }
613                     break;
614                 default:
615                     btstack_assert(false);
616                     return;
617             }
618             break;
619         case AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SOURCE_COMPLETE:
620             switch (hci_event_packet_get_type(packet)){
621                 case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
622                     avdtp_handle_sdp_client_query_attribute_value(connection, packet);
623                     return;
624                 case SDP_EVENT_QUERY_COMPLETE:
625                     status = sdp_event_query_complete_get_status(packet);
626                     if (status != ERROR_CODE_SUCCESS) break;
627                     if (!connection->source_supported) {
628                         status = ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
629                         break;
630                     }
631                     if (connection->avdtp_l2cap_psm == 0) {
632                         status = ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
633                         break;
634                     }
635                     break;
636                 default:
637                     btstack_assert(false);
638                     return;
639             }
640             break;
641         default:
642             // bail out, we must have had an incoming connection in the meantime; just trigger next sdp query on complete
643             if (hci_event_packet_get_type(packet) == SDP_EVENT_QUERY_COMPLETE){
644                 (void) sdp_client_register_query_callback(&avdtp_handle_sdp_client_query_request);
645             }
646             return;
647     }
648 
649     if (status == ERROR_CODE_SUCCESS){
650         avdtp_handle_sdp_query_succeeded(connection);
651         l2cap_create_channel(avdtp_packet_handler, connection->remote_addr, connection->avdtp_l2cap_psm, l2cap_max_mtu(), NULL);
652     } else {
653         avdtp_handle_sdp_query_failed(connection, status);
654     }
655 
656     // register the SDP Query request to check if there is another connection waiting for the query
657     // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
658     (void) sdp_client_register_query_callback(&avdtp_handle_sdp_client_query_request);
659 }
660 
661 static avdtp_connection_t * avdtp_handle_incoming_connection(avdtp_connection_t * connection, bd_addr_t event_addr, uint16_t local_cid){
662     if (connection == NULL){
663         uint16_t cid = avdtp_get_next_cid();
664         connection = avdtp_create_connection(event_addr, cid);
665     }
666 
667     if (connection) {
668         connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
669         connection->l2cap_signaling_cid = local_cid;
670         btstack_run_loop_remove_timer(&connection->retry_timer);
671     }
672     return connection;
673 }
674 
675 static void avdtp_retry_timer_timeout_handler(btstack_timer_source_t * timer){
676     uint16_t avdtp_cid = (uint16_t)(uintptr_t) btstack_run_loop_get_timer_context(timer);
677 
678     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
679     if (connection == NULL) return;
680 
681     if (connection->state == AVDTP_SIGNALING_CONNECTION_W2_L2CAP_RETRY){
682         connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
683         l2cap_create_channel(&avdtp_packet_handler, connection->remote_addr, connection->avdtp_l2cap_psm, l2cap_max_mtu(), NULL);
684     }
685 }
686 
687 static void avdtp_retry_timer_start(avdtp_connection_t * connection){
688     btstack_run_loop_set_timer_handler(&connection->retry_timer, avdtp_retry_timer_timeout_handler);
689     btstack_run_loop_set_timer_context(&connection->retry_timer, (void *)(uintptr_t)connection->avdtp_cid);
690 
691     // add some jitter/randomness to reconnect delay
692     uint32_t timeout = 100 + (btstack_run_loop_get_time_ms() & 0x7F);
693     btstack_run_loop_set_timer(&connection->retry_timer, timeout);
694     btstack_run_loop_add_timer(&connection->retry_timer);
695 }
696 
697 
698 void avdtp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
699     bd_addr_t event_addr;
700     uint16_t psm;
701     uint16_t local_cid;
702     uint8_t  status;
703     uint16_t l2cap_mtu;
704 
705     bool accept_streaming_connection;
706     bool outoing_signaling_active;
707     bool decline_connection;
708 
709     avdtp_stream_endpoint_t * stream_endpoint = NULL;
710     avdtp_connection_t * connection = NULL;
711 
712     switch (packet_type) {
713         case L2CAP_DATA_PACKET:
714             connection = avdtp_get_connection_for_l2cap_signaling_cid(channel);
715             if (connection){
716                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
717                 break;
718             }
719 
720             stream_endpoint = avdtp_get_stream_endpoint_for_l2cap_cid(channel);
721             if (!stream_endpoint){
722                 if (!connection) break;
723                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
724                 break;
725             }
726 
727             if (stream_endpoint->connection){
728                 if (channel == stream_endpoint->connection->l2cap_signaling_cid){
729                     handle_l2cap_data_packet_for_signaling_connection(stream_endpoint->connection, packet, size);
730                     break;
731                 }
732             }
733 
734             if (channel == stream_endpoint->l2cap_media_cid){
735                 btstack_assert(avdtp_sink_handle_media_data);
736                 (*avdtp_sink_handle_media_data)(avdtp_local_seid(stream_endpoint), packet, size);
737                 break;
738             }
739 
740             if (channel == stream_endpoint->l2cap_reporting_cid){
741                 log_info("L2CAP_DATA_PACKET for reporting: NOT IMPLEMENTED");
742             } else if (channel == stream_endpoint->l2cap_recovery_cid){
743                 log_info("L2CAP_DATA_PACKET for recovery: NOT IMPLEMENTED");
744             } else {
745                 log_error("avdtp packet handler L2CAP_DATA_PACKET: local cid 0x%02x not found", channel);
746             }
747             break;
748 
749         case HCI_EVENT_PACKET:
750             switch (hci_event_packet_get_type(packet)) {
751 
752                 case L2CAP_EVENT_INCOMING_CONNECTION:
753                     l2cap_event_incoming_connection_get_address(packet, event_addr);
754                     local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
755 
756                     outoing_signaling_active = false;
757                     accept_streaming_connection = false;
758 
759                     connection = avdtp_get_connection_for_bd_addr(event_addr);
760                     if (connection != NULL){
761                         switch (connection->state){
762                             case AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED:
763                             case AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED:
764                                 outoing_signaling_active = true;
765                                 connection->incoming_declined = true;
766                                 break;
767                             case AVDTP_SIGNALING_CONNECTION_OPENED:
768                                 outoing_signaling_active = true;
769                                 accept_streaming_connection = true;
770                                 break;
771                             default:
772                                 break;
773                         }
774                     }
775                     log_info("incoming: %s, outoing_signaling_active %d, accept_streaming_connection %d",
776                         bd_addr_to_str(event_addr), outoing_signaling_active, accept_streaming_connection);
777 
778                     decline_connection = outoing_signaling_active && !accept_streaming_connection;
779                     if (outoing_signaling_active == false){
780                         connection = avdtp_handle_incoming_connection(connection, event_addr, local_cid);
781                         if (connection == NULL){
782                             decline_connection = true;
783                         }
784                     } else if (accept_streaming_connection){
785                         if ((connection == NULL) || (connection->configuration_state != AVDTP_CONFIGURATION_STATE_REMOTE_CONFIGURED)) {
786                             decline_connection = true;
787                         } else {
788                             // now, we're only dealing with media connections that are created by remote side - we're acceptor here
789                             stream_endpoint = avdtp_get_stream_endpoint_with_seid(connection->acceptor_local_seid);
790                             if ((stream_endpoint == NULL) || (stream_endpoint->l2cap_media_cid != 0) ) {
791                                 decline_connection = true;
792                             }
793                         }
794                     }
795 
796                     if (decline_connection){
797                         l2cap_decline_connection(local_cid);
798                     } else {
799                         l2cap_accept_connection(local_cid);
800                     }
801                     break;
802 
803                 case L2CAP_EVENT_CHANNEL_OPENED:
804 
805                     psm = l2cap_event_channel_opened_get_psm(packet);
806                     if (psm != BLUETOOTH_PSM_AVDTP){
807                         log_info("Unexpected PSM - Not implemented yet, avdtp sink: L2CAP_EVENT_CHANNEL_OPENED ");
808                         return;
809                     }
810 
811                     status = l2cap_event_channel_opened_get_status(packet);
812                     // inform about new l2cap connection
813                     l2cap_event_channel_opened_get_address(packet, event_addr);
814                     local_cid = l2cap_event_channel_opened_get_local_cid(packet);
815                     l2cap_mtu = l2cap_event_channel_opened_get_remote_mtu(packet);
816                     connection = avdtp_get_connection_for_bd_addr(event_addr);
817                     if (connection == NULL){
818                         log_info("L2CAP_EVENT_CHANNEL_OPENED: no connection found for %s", bd_addr_to_str(event_addr));
819                         break;
820                     }
821 
822                     switch (connection->state){
823                         case AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED:
824                             switch (status){
825                                 case ERROR_CODE_SUCCESS:
826                                     connection->l2cap_signaling_cid = local_cid;
827                                     connection->incoming_declined = false;
828                                     connection->l2cap_mtu = l2cap_mtu;
829                                     connection->state = AVDTP_SIGNALING_CONNECTION_OPENED;
830                                     log_info("Connection opened l2cap_signaling_cid 0x%02x, avdtp_cid 0x%02x", connection->l2cap_signaling_cid, connection->avdtp_cid);
831                                     avdtp_signaling_emit_connection_established(connection->avdtp_cid, event_addr,
832                                                                                 status);
833                                     return;
834                                 case L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_RESOURCES:
835                                     if (connection->incoming_declined == true) {
836                                         log_info("Connection was declined, and the outgoing failed");
837                                         connection->state = AVDTP_SIGNALING_CONNECTION_W2_L2CAP_RETRY;
838                                         connection->incoming_declined = false;
839                                         avdtp_retry_timer_start(connection);
840                                         return;
841                                     }
842                                     break;
843                                 default:
844                                     log_info("Connection to %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
845                                     break;
846                             }
847                             avdtp_signaling_emit_connection_established(connection->avdtp_cid, event_addr, status);
848                             avdtp_finalize_connection(connection);
849                             break;
850 
851                         case AVDTP_SIGNALING_CONNECTION_OPENED:
852                             stream_endpoint = avdtp_get_stream_endpoint_for_signaling_cid(connection->l2cap_signaling_cid);
853                             if (!stream_endpoint){
854                                 log_info("L2CAP_EVENT_CHANNEL_OPENED: stream_endpoint not found for signaling cid 0x%02x", connection->l2cap_signaling_cid);
855                                 return;
856                             }
857                             if (status != ERROR_CODE_SUCCESS){
858                                 log_info("AVDTP_STREAM_ENDPOINT_OPENED failed with status %d, avdtp cid 0x%02x, l2cap_media_cid 0x%02x, local seid %d, remote seid %d", status, connection->avdtp_cid, stream_endpoint->l2cap_media_cid, avdtp_local_seid(stream_endpoint), avdtp_remote_seid(stream_endpoint));
859                                 stream_endpoint->state = AVDTP_STREAM_ENDPOINT_IDLE;
860                                 avdtp_streaming_emit_connection_established(stream_endpoint, status);
861                                 break;
862                             }
863                             switch (stream_endpoint->state){
864                                 case AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_CONNECTED:
865                                     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_OPENED;
866                                     stream_endpoint->l2cap_media_cid = l2cap_event_channel_opened_get_local_cid(packet);
867                                     stream_endpoint->media_con_handle = l2cap_event_channel_opened_get_handle(packet);
868 
869                                     log_info("AVDTP_STREAM_ENDPOINT_OPENED, avdtp cid 0x%02x, l2cap_media_cid 0x%02x, local seid %d, remote seid %d", connection->avdtp_cid, stream_endpoint->l2cap_media_cid, avdtp_local_seid(stream_endpoint), avdtp_remote_seid(stream_endpoint));
870                                     avdtp_streaming_emit_connection_established(stream_endpoint, ERROR_CODE_SUCCESS);
871                                     break;
872                                 default:
873                                     log_info("AVDTP_STREAM_ENDPOINT_OPENED failed - stream endpoint in wrong state %d, avdtp cid 0x%02x, l2cap_media_cid 0x%02x, local seid %d, remote seid %d", stream_endpoint->state, connection->avdtp_cid, stream_endpoint->l2cap_media_cid, avdtp_local_seid(stream_endpoint), avdtp_remote_seid(stream_endpoint));
874                                     avdtp_streaming_emit_connection_established(stream_endpoint, ERROR_CODE_COMMAND_DISALLOWED);
875                                     break;
876                             }
877                             break;
878 
879                         default:
880                             log_info("L2CAP connection to %s ignored: status code 0x%02x, connection state %d", bd_addr_to_str(event_addr), status, connection->state);
881                             break;
882                     }
883                     break;
884 
885                 case L2CAP_EVENT_CHANNEL_CLOSED:
886                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
887                     stream_endpoint = avdtp_get_stream_endpoint_for_l2cap_cid(local_cid);
888                     connection = avdtp_get_connection_for_l2cap_signaling_cid(local_cid);
889 
890                     log_info("Received L2CAP_EVENT_CHANNEL_CLOSED, cid 0x%2x, connection %p, stream_endpoint %p", local_cid, connection, stream_endpoint);
891 
892                     if (stream_endpoint){
893                         if (stream_endpoint->l2cap_media_cid == local_cid){
894                             connection = stream_endpoint->connection;
895                             if (connection) {
896                                 avdtp_streaming_emit_connection_released(stream_endpoint,
897                                                                          connection->avdtp_cid,
898                                                                          avdtp_local_seid(stream_endpoint));
899                             }
900                             avdtp_reset_stream_endpoint(stream_endpoint);
901                             break;
902                         }
903                         if (stream_endpoint->l2cap_recovery_cid == local_cid){
904                             log_info("L2CAP_EVENT_CHANNEL_CLOSED recovery cid 0x%0x", local_cid);
905                             stream_endpoint->l2cap_recovery_cid = 0;
906                             break;
907                         }
908 
909                         if (stream_endpoint->l2cap_reporting_cid == local_cid){
910                             log_info("L2CAP_EVENT_CHANNEL_CLOSED reporting cid 0x%0x", local_cid);
911                             stream_endpoint->l2cap_reporting_cid = 0;
912                             break;
913                         }
914                     }
915 
916                     if (connection){
917                         btstack_linked_list_iterator_t it;
918                         btstack_linked_list_iterator_init(&it, avdtp_get_stream_endpoints());
919                         while (btstack_linked_list_iterator_has_next(&it)){
920                             stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
921                             if (stream_endpoint->connection == connection){
922                                 avdtp_reset_stream_endpoint(stream_endpoint);
923                             }
924                         }
925                         avdtp_signaling_emit_connection_released(connection->avdtp_cid);
926                         avdtp_finalize_connection(connection);
927                         break;
928                     }
929                     break;
930 
931                 case HCI_EVENT_DISCONNECTION_COMPLETE:
932                     break;
933 
934                 case L2CAP_EVENT_CAN_SEND_NOW:
935                     log_debug("avdtp_packet_handler, L2CAP_EVENT_CAN_SEND_NOW l2cap_cid 0x%02x", channel);
936                     connection = avdtp_get_connection_for_l2cap_signaling_cid(channel);
937                     if (!connection) {
938                         stream_endpoint = avdtp_get_stream_endpoint_for_l2cap_cid(channel);
939                         if (!stream_endpoint->connection) break;
940                         connection = stream_endpoint->connection;
941                     }
942                     avdtp_handle_can_send_now(connection, channel);
943                     break;
944                 default:
945                     log_info("Unknown HCI event type %02x", hci_event_packet_get_type(packet));
946                     break;
947             }
948             break;
949 
950         default:
951             // other packet type
952             break;
953     }
954 }
955 
956 uint8_t avdtp_disconnect(uint16_t avdtp_cid){
957     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
958     if (!connection) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
959 
960     if (connection->state == AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED) return ERROR_CODE_SUCCESS;
961 
962     btstack_linked_list_iterator_t it;
963     btstack_linked_list_iterator_init(&it, avdtp_get_stream_endpoints());
964 
965     while (btstack_linked_list_iterator_has_next(&it)){
966         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
967         if (stream_endpoint->connection != connection) continue;
968 
969         switch (stream_endpoint->state){
970             case AVDTP_STREAM_ENDPOINT_OPENED:
971             case AVDTP_STREAM_ENDPOINT_STREAMING:
972                 stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_DISCONNECTED;
973                 l2cap_disconnect(stream_endpoint->l2cap_media_cid, 0);
974                 break;
975             default:
976                 break;
977         }
978     }
979 
980     connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED;
981     l2cap_disconnect(connection->l2cap_signaling_cid, 0);
982     return ERROR_CODE_SUCCESS;
983 }
984 
985 uint8_t avdtp_open_stream(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid){
986     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
987     if (!connection){
988         log_error("avdtp_media_connect: no connection for signaling cid 0x%02x found", avdtp_cid);
989         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
990     }
991 
992     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) {
993         log_error("avdtp_media_connect: wrong connection state %d", connection->state);
994         return ERROR_CODE_COMMAND_DISALLOWED;
995     }
996 
997     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
998     if (!stream_endpoint) {
999         log_error("avdtp_media_connect: no stream_endpoint with seid %d found", local_seid);
1000         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1001     }
1002 
1003     if (stream_endpoint->remote_sep.seid != remote_seid){
1004         log_error("avdtp_media_connect: no remote sep with seid %d registered with the stream endpoint", remote_seid);
1005         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1006     }
1007 
1008     if (stream_endpoint->state < AVDTP_STREAM_ENDPOINT_CONFIGURED) return ERROR_CODE_COMMAND_DISALLOWED;
1009 
1010     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1011     connection->initiator_remote_seid = remote_seid;
1012     connection->initiator_local_seid = local_seid;
1013     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_OPEN_STREAM;
1014     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W2_REQUEST_OPEN_STREAM;
1015     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1016     return ERROR_CODE_SUCCESS;
1017 }
1018 
1019 uint8_t avdtp_start_stream(uint16_t avdtp_cid, uint8_t local_seid){
1020     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1021     if (!connection){
1022         log_error("avdtp_start_stream: no connection for signaling cid 0x%02x found", avdtp_cid);
1023         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1024     }
1025 
1026     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
1027     if (!stream_endpoint) {
1028         log_error("avdtp_start_stream: no stream_endpoint with seid %d found", local_seid);
1029         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1030     }
1031 
1032     if (stream_endpoint->l2cap_media_cid == 0){
1033         log_error("avdtp_start_stream: no media connection for stream_endpoint with seid %d found", local_seid);
1034         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1035     }
1036 
1037     if (!is_avdtp_remote_seid_registered(stream_endpoint)){
1038         log_error("avdtp_media_connect: no remote sep registered with the stream endpoint");
1039         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1040     }
1041 
1042     if (!is_avdtp_remote_seid_registered(stream_endpoint) || stream_endpoint->start_stream == 1){
1043         return ERROR_CODE_COMMAND_DISALLOWED;
1044     }
1045 
1046     stream_endpoint->start_stream = 1;
1047     connection->initiator_local_seid = local_seid;
1048     connection->initiator_remote_seid = stream_endpoint->remote_sep.seid;
1049     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1050     return ERROR_CODE_SUCCESS;
1051 }
1052 
1053 uint8_t avdtp_stop_stream(uint16_t avdtp_cid, uint8_t local_seid){
1054     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1055     if (!connection){
1056         log_error("avdtp_stop_stream: no connection for signaling cid 0x%02x found", avdtp_cid);
1057         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1058     }
1059 
1060     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
1061     if (!stream_endpoint) {
1062         log_error("avdtp_stop_stream: no stream_endpoint with seid %d found", local_seid);
1063         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1064     }
1065 
1066     if (stream_endpoint->l2cap_media_cid == 0){
1067         log_error("avdtp_stop_stream: no media connection for stream_endpoint with seid %d found", local_seid);
1068         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1069     }
1070 
1071     if (!is_avdtp_remote_seid_registered(stream_endpoint) || stream_endpoint->stop_stream){
1072         return ERROR_CODE_COMMAND_DISALLOWED;
1073     }
1074 
1075     stream_endpoint->stop_stream = 1;
1076     connection->initiator_local_seid = local_seid;
1077     connection->initiator_remote_seid = stream_endpoint->remote_sep.seid;
1078     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1079     return ERROR_CODE_SUCCESS;
1080 }
1081 
1082 uint8_t avdtp_abort_stream(uint16_t avdtp_cid, uint8_t local_seid){
1083     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1084     if (!connection){
1085         log_error("avdtp_abort_stream: no connection for signaling cid 0x%02x found", avdtp_cid);
1086         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1087     }
1088 
1089     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
1090     if (!stream_endpoint) {
1091         log_error("avdtp_abort_stream: no stream_endpoint with seid %d found", local_seid);
1092         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1093     }
1094 
1095     if (stream_endpoint->l2cap_media_cid == 0){
1096         log_error("avdtp_abort_stream: no media connection for stream_endpoint with seid %d found", local_seid);
1097         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1098     }
1099 
1100     if (!is_avdtp_remote_seid_registered(stream_endpoint) || stream_endpoint->abort_stream){
1101         return ERROR_CODE_COMMAND_DISALLOWED;
1102     }
1103 
1104     stream_endpoint->abort_stream = 1;
1105     connection->initiator_local_seid = local_seid;
1106     connection->initiator_remote_seid = stream_endpoint->remote_sep.seid;
1107     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1108     return ERROR_CODE_SUCCESS;
1109 }
1110 
1111 uint8_t avdtp_suspend_stream(uint16_t avdtp_cid, uint8_t local_seid){
1112     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1113     if (!connection){
1114         log_error("avdtp_suspend_stream: no connection for signaling cid 0x%02x found", avdtp_cid);
1115         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1116     }
1117     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
1118     if (!stream_endpoint) {
1119         log_error("avdtp_suspend_stream: no stream_endpoint with seid %d found", local_seid);
1120         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1121     }
1122 
1123     if (stream_endpoint->l2cap_media_cid == 0){
1124         log_error("avdtp_suspend_stream: no media connection for stream_endpoint with seid %d found", local_seid);
1125         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1126     }
1127 
1128     if (!is_avdtp_remote_seid_registered(stream_endpoint) || stream_endpoint->suspend_stream){
1129         return ERROR_CODE_COMMAND_DISALLOWED;
1130     }
1131 
1132     stream_endpoint->suspend_stream = 1;
1133     connection->initiator_local_seid = local_seid;
1134     connection->initiator_remote_seid = stream_endpoint->remote_sep.seid;
1135     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1136     return ERROR_CODE_SUCCESS;
1137 }
1138 
1139 uint8_t avdtp_discover_stream_endpoints(uint16_t avdtp_cid){
1140     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1141     if (!connection){
1142         log_error("avdtp_discover_stream_endpoints: no connection for signaling cid 0x%02x found", avdtp_cid);
1143         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1144     }
1145     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1146         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1147         return ERROR_CODE_COMMAND_DISALLOWED;
1148     }
1149 
1150     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1151     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_DISCOVER_SEPS;
1152     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1153 }
1154 
1155 
1156 uint8_t avdtp_get_capabilities(uint16_t avdtp_cid, uint8_t remote_seid){
1157     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1158     if (!connection){
1159         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1160         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1161     }
1162     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1163         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1164         return ERROR_CODE_COMMAND_DISALLOWED;
1165     }
1166 
1167     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1168     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CAPABILITIES;
1169     connection->initiator_remote_seid = remote_seid;
1170     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1171 }
1172 
1173 
1174 uint8_t avdtp_get_all_capabilities(uint16_t avdtp_cid, uint8_t remote_seid){
1175     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1176     if (!connection){
1177         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1178         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1179     }
1180     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1181         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1182         return ERROR_CODE_COMMAND_DISALLOWED;
1183     }
1184 
1185     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1186     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_ALL_CAPABILITIES;
1187     connection->initiator_remote_seid = remote_seid;
1188     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1189 }
1190 
1191 uint8_t avdtp_get_configuration(uint16_t avdtp_cid, uint8_t remote_seid){
1192     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1193     if (!connection){
1194         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1195         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1196     }
1197     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1198         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1199         return ERROR_CODE_COMMAND_DISALLOWED;
1200     }
1201 
1202     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1203     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CONFIGURATION;
1204     connection->initiator_remote_seid = remote_seid;
1205     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1206 }
1207 
1208 uint8_t avdtp_set_configuration(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid, uint16_t configured_services_bitmap, avdtp_capabilities_t configuration){
1209     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1210     if (!connection){
1211         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1212         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1213     }
1214     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1215         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1216         log_error("connection in wrong state, %d, initiator state %d", connection->state, connection->initiator_connection_state);
1217         return ERROR_CODE_COMMAND_DISALLOWED;
1218     }
1219     if (connection->configuration_state != AVDTP_CONFIGURATION_STATE_IDLE){
1220         log_info("configuration already started, config state %u", connection->configuration_state);
1221         return ERROR_CODE_COMMAND_DISALLOWED;
1222     }
1223 
1224     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_for_seid(local_seid);
1225     if (!stream_endpoint) {
1226         log_error("No initiator stream endpoint for seid %d", local_seid);
1227         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1228     }
1229     if (stream_endpoint->state >= AVDTP_STREAM_ENDPOINT_CONFIGURED){
1230         log_error("Stream endpoint seid %d in wrong state %d", local_seid, stream_endpoint->state);
1231         return ERROR_CODE_COMMAND_DISALLOWED;
1232     }
1233 
1234     connection->active_stream_endpoint = (void*) stream_endpoint;
1235     connection->configuration_state = AVDTP_CONFIGURATION_STATE_LOCAL_INITIATED;
1236 
1237     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1238     connection->initiator_remote_seid = remote_seid;
1239     connection->initiator_local_seid = local_seid;
1240     stream_endpoint->remote_configuration_bitmap = configured_services_bitmap;
1241     stream_endpoint->remote_configuration = configuration;
1242     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_SET_CONFIGURATION;
1243 
1244     // cache media codec information for SBC
1245     stream_endpoint->media_codec_type = configuration.media_codec.media_codec_type;
1246     if (configuration.media_codec.media_codec_type == AVDTP_CODEC_SBC){
1247         stream_endpoint->media_type = configuration.media_codec.media_type;
1248         (void)memcpy(stream_endpoint->media_codec_sbc_info,
1249                      configuration.media_codec.media_codec_information, 4);
1250     }
1251     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1252 }
1253 
1254 uint8_t avdtp_reconfigure(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid, uint16_t configured_services_bitmap, avdtp_capabilities_t configuration){
1255     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1256     if (!connection){
1257         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1258         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1259     }
1260     //TODO: if opened only app capabilities, enable reconfigure for not opened
1261     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1262         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1263         return ERROR_CODE_COMMAND_DISALLOWED;
1264     }
1265 
1266     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_for_seid(local_seid);
1267     if (!stream_endpoint) {
1268         log_error("avdtp_reconfigure: no initiator stream endpoint for seid %d", local_seid);
1269         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1270     }
1271 
1272     if (!is_avdtp_remote_seid_registered(stream_endpoint)){
1273         log_error("avdtp_reconfigure: no associated remote sep");
1274         return ERROR_CODE_COMMAND_DISALLOWED;
1275     }
1276 
1277     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1278     connection->initiator_remote_seid = remote_seid;
1279     connection->initiator_local_seid = local_seid;
1280     stream_endpoint->remote_configuration_bitmap = configured_services_bitmap;
1281     stream_endpoint->remote_configuration = configuration;
1282     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_RECONFIGURE_STREAM_WITH_SEID;
1283     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1284 }
1285 
1286 void    avdtp_set_preferred_sampling_frequeny(avdtp_stream_endpoint_t * stream_endpoint, uint32_t sampling_frequency){
1287     stream_endpoint->preferred_sampling_frequency = sampling_frequency;
1288 }
1289 
1290 uint8_t avdtp_choose_sbc_channel_mode(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_channel_mode_bitmap){
1291     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1292     uint8_t channel_mode_bitmap = (media_codec[0] & 0x0F) & remote_channel_mode_bitmap;
1293 
1294     uint8_t channel_mode = AVDTP_SBC_STEREO;
1295     if (channel_mode_bitmap & AVDTP_SBC_JOINT_STEREO){
1296         channel_mode = AVDTP_SBC_JOINT_STEREO;
1297     } else if (channel_mode_bitmap & AVDTP_SBC_STEREO){
1298         channel_mode = AVDTP_SBC_STEREO;
1299     } else if (channel_mode_bitmap & AVDTP_SBC_DUAL_CHANNEL){
1300         channel_mode = AVDTP_SBC_DUAL_CHANNEL;
1301     } else if (channel_mode_bitmap & AVDTP_SBC_MONO){
1302         channel_mode = AVDTP_SBC_MONO;
1303     }
1304     return channel_mode;
1305 }
1306 
1307 uint8_t avdtp_choose_sbc_allocation_method(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_allocation_method_bitmap){
1308     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1309     uint8_t allocation_method_bitmap = (media_codec[1] & 0x03) & remote_allocation_method_bitmap;
1310 
1311     uint8_t allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
1312     if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS){
1313         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
1314     } else if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_SNR){
1315         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_SNR;
1316     }
1317     return allocation_method;
1318 }
1319 
1320 uint8_t avdtp_stream_endpoint_seid(avdtp_stream_endpoint_t * stream_endpoint){
1321     if (!stream_endpoint) return 0;
1322     return stream_endpoint->sep.seid;
1323 }
1324 uint8_t avdtp_choose_sbc_subbands(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_subbands_bitmap){
1325     if (!stream_endpoint) return 0;
1326     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1327     uint8_t subbands_bitmap = ((media_codec[1] >> 2) & 0x03) & remote_subbands_bitmap;
1328 
1329     uint8_t subbands = AVDTP_SBC_SUBBANDS_8;
1330     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_8){
1331         subbands = AVDTP_SBC_SUBBANDS_8;
1332     } else if (subbands_bitmap & AVDTP_SBC_SUBBANDS_4){
1333         subbands = AVDTP_SBC_SUBBANDS_4;
1334     }
1335     return subbands;
1336 }
1337 
1338 uint8_t avdtp_choose_sbc_block_length(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_block_length_bitmap){
1339     if (!stream_endpoint) return 0;
1340     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1341     uint8_t block_length_bitmap = (media_codec[1] >> 4) & remote_block_length_bitmap;
1342 
1343     uint8_t block_length = AVDTP_SBC_BLOCK_LENGTH_16;
1344     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_16){
1345         block_length = AVDTP_SBC_BLOCK_LENGTH_16;
1346     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_12){
1347         block_length = AVDTP_SBC_BLOCK_LENGTH_12;
1348     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_8){
1349         block_length = AVDTP_SBC_BLOCK_LENGTH_8;
1350     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_4){
1351         block_length = AVDTP_SBC_BLOCK_LENGTH_4;
1352     }
1353     return block_length;
1354 }
1355 
1356 uint8_t avdtp_choose_sbc_sampling_frequency(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_sampling_frequency_bitmap){
1357     if (!stream_endpoint) return 0;
1358     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1359     uint8_t supported_sampling_frequency_bitmap = (media_codec[0] >> 4) & remote_sampling_frequency_bitmap;
1360 
1361     // use preferred sampling frequency if possible
1362     if ((stream_endpoint->preferred_sampling_frequency == 48000) && (supported_sampling_frequency_bitmap & AVDTP_SBC_48000)){
1363         return AVDTP_SBC_48000;
1364     }
1365     if ((stream_endpoint->preferred_sampling_frequency == 44100) && (supported_sampling_frequency_bitmap & AVDTP_SBC_44100)){
1366         return AVDTP_SBC_44100;
1367     }
1368     if ((stream_endpoint->preferred_sampling_frequency == 32000) && (supported_sampling_frequency_bitmap & AVDTP_SBC_32000)){
1369         return AVDTP_SBC_32000;
1370     }
1371     if ((stream_endpoint->preferred_sampling_frequency == 16000) && (supported_sampling_frequency_bitmap & AVDTP_SBC_16000)){
1372         return AVDTP_SBC_16000;
1373     }
1374 
1375     // otherwise, use highest available
1376     if (supported_sampling_frequency_bitmap & AVDTP_SBC_48000){
1377         return AVDTP_SBC_48000;
1378     }
1379     if (supported_sampling_frequency_bitmap & AVDTP_SBC_44100){
1380         return AVDTP_SBC_44100;
1381     }
1382     if (supported_sampling_frequency_bitmap & AVDTP_SBC_32000){
1383         return AVDTP_SBC_32000;
1384     }
1385     if (supported_sampling_frequency_bitmap & AVDTP_SBC_16000){
1386         return AVDTP_SBC_16000;
1387     }
1388     return AVDTP_SBC_44100; // some default
1389 }
1390 
1391 uint8_t avdtp_choose_sbc_max_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_max_bitpool_value){
1392     if (!stream_endpoint) return 0;
1393     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1394     return btstack_min(media_codec[3], remote_max_bitpool_value);
1395 }
1396 
1397 uint8_t avdtp_choose_sbc_min_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_min_bitpool_value){
1398     if (!stream_endpoint) return 0;
1399     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1400     return btstack_max(media_codec[2], remote_min_bitpool_value);
1401 }
1402 
1403 uint8_t is_avdtp_remote_seid_registered(avdtp_stream_endpoint_t * stream_endpoint){
1404     if (!stream_endpoint) return 0;
1405     if (stream_endpoint->remote_sep.seid == 0) return 0;
1406     if (stream_endpoint->remote_sep.seid > 0x3E) return 0;
1407     return 1;
1408 }
1409 
1410 void avdtp_init(void){
1411     static bool l2cap_registered = false;
1412     if (!l2cap_registered){
1413         l2cap_registered = true;
1414         l2cap_register_service(&avdtp_packet_handler, BLUETOOTH_PSM_AVDTP, 0xffff, gap_get_security_level());
1415     }
1416 }
1417