xref: /btstack/src/classic/avdtp.c (revision cfd54eb73cd29e7bf738f261fb454a84a1bb66b0)
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             case AVDTP_SIGNALING_CONNECTION_OPENED:
268                 if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_SEND_SDP_QUERY_THEN_GET_ALL_CAPABILITIES) continue;
269                 connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W4_SDP_QUERY_COMPLETE_THEN_GET_ALL_CAPABILITIES;
270                 break;
271             default:
272                 continue;
273         }
274         sdp_query_context_avdtp_cid = connection->avdtp_cid;
275         sdp_client_query_uuid16(&avdtp_handle_sdp_client_query_result, (uint8_t *) connection->remote_addr, BLUETOOTH_PROTOCOL_AVDTP);
276         return;
277     }
278 }
279 
280 uint8_t avdtp_connect(bd_addr_t remote, avdtp_role_t role, uint16_t * avdtp_cid){
281     avdtp_connection_t * connection = avdtp_get_connection_for_bd_addr(remote);
282     if (connection){
283         return ERROR_CODE_COMMAND_DISALLOWED;
284     }
285 
286     uint16_t cid = avdtp_get_next_cid();
287     if (avdtp_cid != NULL) {
288         *avdtp_cid = cid;
289     }
290 
291     connection = avdtp_create_connection(remote, cid);
292     if (!connection) return BTSTACK_MEMORY_ALLOC_FAILED;
293 
294     connection->avdtp_cid = cid;
295 
296     connection->avdtp_l2cap_psm = 0;
297     connection->avdtp_version  = 0;
298     connection->sink_supported = false;
299     connection->source_supported = false;
300 
301     switch (role){
302         case AVDTP_ROLE_SOURCE:
303             connection->state = AVDTP_SIGNALING_W2_SEND_SDP_QUERY_FOR_REMOTE_SINK;
304             break;
305         case AVDTP_ROLE_SINK:
306             connection->state = AVDTP_SIGNALING_W2_SEND_SDP_QUERY_FOR_REMOTE_SOURCE;
307             break;
308         default:
309             btstack_assert(false);
310             return ERROR_CODE_COMMAND_DISALLOWED;
311     }
312 
313     avdtp_handle_sdp_client_query_request.callback = &avdtp_handle_start_sdp_client_query;
314     // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
315     (void) sdp_client_register_query_callback(&avdtp_handle_sdp_client_query_request);
316     return ERROR_CODE_SUCCESS;
317 }
318 
319 
320 void avdtp_register_sink_packet_handler(btstack_packet_handler_t callback){
321     btstack_assert(callback != NULL);
322     avdtp_sink_callback = callback;
323 }
324 
325 void avdtp_register_source_packet_handler(btstack_packet_handler_t callback){
326     btstack_assert(callback != NULL);
327     avdtp_source_callback = callback;
328 }
329 
330 void avdtp_register_media_transport_category(avdtp_stream_endpoint_t * stream_endpoint){
331     if (!stream_endpoint){
332         log_error("Stream endpoint with given seid is not registered.");
333         return;
334     }
335     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_TRANSPORT, 1);
336     stream_endpoint->sep.registered_service_categories = bitmap;
337 }
338 
339 void avdtp_register_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
340     if (!stream_endpoint){
341         log_error("Stream endpoint with given seid is not registered.");
342         return;
343     }
344     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_REPORTING, 1);
345     stream_endpoint->sep.registered_service_categories = bitmap;
346 }
347 
348 void avdtp_register_delay_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
349     if (!stream_endpoint){
350         log_error("Stream endpoint with given seid is not registered.");
351         return;
352     }
353     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_DELAY_REPORTING, 1);
354     stream_endpoint->sep.registered_service_categories = bitmap;
355 }
356 
357 void avdtp_register_recovery_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t maximum_recovery_window_size, uint8_t maximum_number_media_packets){
358     if (!stream_endpoint){
359         log_error("Stream endpoint with given seid is not registered.");
360         return;
361     }
362     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_RECOVERY, 1);
363     stream_endpoint->sep.registered_service_categories = bitmap;
364     stream_endpoint->sep.capabilities.recovery.recovery_type = 0x01; // 0x01 = RFC2733
365     stream_endpoint->sep.capabilities.recovery.maximum_recovery_window_size = maximum_recovery_window_size;
366     stream_endpoint->sep.capabilities.recovery.maximum_number_media_packets = maximum_number_media_packets;
367 }
368 
369 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){
370     if (!stream_endpoint){
371         log_error("Stream endpoint with given seid is not registered.");
372         return;
373     }
374     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_CONTENT_PROTECTION, 1);
375     stream_endpoint->sep.registered_service_categories = bitmap;
376     stream_endpoint->sep.capabilities.content_protection.cp_type = cp_type;
377     (void)memcpy(stream_endpoint->sep.capabilities.content_protection.cp_type_value,
378                  cp_type_value,
379                  btstack_min(cp_type_value_len, AVDTP_MAX_CONTENT_PROTECTION_TYPE_VALUE_LEN));
380     stream_endpoint->sep.capabilities.content_protection.cp_type_value_len = btstack_min(cp_type_value_len, AVDTP_MAX_CONTENT_PROTECTION_TYPE_VALUE_LEN);
381 }
382 
383 void avdtp_register_header_compression_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t back_ch, uint8_t media, uint8_t recovery){
384     if (!stream_endpoint){
385         log_error("Stream endpoint with given seid is not registered.");
386         return;
387     }
388     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_HEADER_COMPRESSION, 1);
389     stream_endpoint->sep.registered_service_categories = bitmap;
390     stream_endpoint->sep.capabilities.header_compression.back_ch = back_ch;
391     stream_endpoint->sep.capabilities.header_compression.media = media;
392     stream_endpoint->sep.capabilities.header_compression.recovery = recovery;
393 }
394 
395 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){
396     if (!stream_endpoint){
397         log_error("Stream endpoint with given seid is not registered.");
398         return;
399     }
400     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_CODEC, 1);
401     stream_endpoint->sep.registered_service_categories = bitmap;
402     stream_endpoint->sep.capabilities.media_codec.media_type = media_type;
403     stream_endpoint->sep.capabilities.media_codec.media_codec_type = media_codec_type;
404     stream_endpoint->sep.capabilities.media_codec.media_codec_information = media_codec_info;
405     stream_endpoint->sep.capabilities.media_codec.media_codec_information_len = media_codec_info_len;
406 }
407 
408 void avdtp_register_multiplexing_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t fragmentation){
409     if (!stream_endpoint){
410         log_error("Stream endpoint with given seid is not registered.");
411         return;
412     }
413     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MULTIPLEXING, 1);
414     stream_endpoint->sep.registered_service_categories = bitmap;
415     stream_endpoint->sep.capabilities.multiplexing_mode.fragmentation = fragmentation;
416 }
417 
418 void avdtp_register_media_handler(void (*callback)(uint8_t local_seid, uint8_t *packet, uint16_t size)){
419     avdtp_sink_handle_media_data = callback;
420 }
421 
422 /* START: tracking can send now requests pro l2cap cid */
423 void avdtp_handle_can_send_now(avdtp_connection_t *connection, uint16_t l2cap_cid) {
424     if (connection->wait_to_send_acceptor){
425         log_debug("call avdtp_acceptor_stream_config_subsm_run");
426         connection->wait_to_send_acceptor = 0;
427         avdtp_acceptor_stream_config_subsm_run(connection);
428     } else if (connection->wait_to_send_initiator){
429         log_debug("call avdtp_initiator_stream_config_subsm_run");
430         connection->wait_to_send_initiator = 0;
431         avdtp_initiator_stream_config_subsm_run(connection);
432     }
433 
434     // re-register
435     bool more_to_send = connection->wait_to_send_acceptor || connection->wait_to_send_initiator;
436     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);
437 
438     if (more_to_send){
439         l2cap_request_can_send_now_event(l2cap_cid);
440     }
441 }
442 /* END: tracking can send now requests pro l2cap cid */
443 
444 
445 avdtp_stream_endpoint_t * avdtp_create_stream_endpoint(avdtp_sep_type_t sep_type, avdtp_media_type_t media_type){
446     avdtp_stream_endpoint_t * stream_endpoint = btstack_memory_avdtp_stream_endpoint_get();
447     if (!stream_endpoint){
448         log_error("Not enough memory to create stream endpoint");
449         return NULL;
450     }
451     stream_endpoint->sep.seid = avdtp_get_next_local_seid();
452     stream_endpoint->sep.media_type = media_type;
453     stream_endpoint->sep.type = sep_type;
454     btstack_linked_list_add(avdtp_get_stream_endpoints(), (btstack_linked_item_t *) stream_endpoint);
455     return stream_endpoint;
456 }
457 
458 void avdtp_finalize_stream_endpoint(avdtp_stream_endpoint_t * stream_endpoint){
459     btstack_linked_list_remove(avdtp_get_stream_endpoints(), (btstack_linked_item_t* ) stream_endpoint);
460     btstack_memory_avdtp_stream_endpoint_free(stream_endpoint);
461 }
462 
463 static void
464 handle_l2cap_data_packet_for_signaling_connection(avdtp_connection_t *connection, uint8_t *packet, uint16_t size) {
465     if (size < 2) return;
466 
467     uint16_t offset;
468     avdtp_message_type_t message_type = avdtp_get_signaling_packet_type(packet);
469     switch (message_type){
470         case AVDTP_CMD_MSG:
471             offset = avdtp_read_signaling_header(&connection->acceptor_signaling_packet, packet, size);
472             avdtp_acceptor_stream_config_subsm(connection, packet, size, offset);
473             break;
474         default:
475             offset = avdtp_read_signaling_header(&connection->initiator_signaling_packet, packet, size);
476             avdtp_initiator_stream_config_subsm(connection, packet, size, offset);
477             break;
478     }
479 }
480 
481 static void avdtp_handle_sdp_client_query_attribute_value(avdtp_connection_t * connection, uint8_t *packet){
482     des_iterator_t des_list_it;
483     des_iterator_t prot_it;
484 
485     // Handle new SDP record
486     if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id) {
487         record_id = sdp_event_query_attribute_byte_get_record_id(packet);
488         // log_info("SDP Record: Nr: %d", record_id);
489     }
490 
491     if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
492         attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
493 
494         if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
495 
496             switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
497 
498                 case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
499                     if (de_get_element_type(attribute_value) != DE_DES) break;
500                     for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
501                         uint8_t * element = des_iterator_get_element(&des_list_it);
502                         if (de_get_element_type(element) != DE_UUID) continue;
503                         uint32_t uuid = de_get_uuid32(element);
504                         switch (uuid){
505                             case BLUETOOTH_SERVICE_CLASS_AUDIO_SOURCE:
506                                 connection->source_supported = true;
507                                 log_info("source_supported");
508                                 break;
509                             case BLUETOOTH_SERVICE_CLASS_AUDIO_SINK:
510                                 connection->sink_supported = true;
511                                 log_info("sink_supported");
512                                 break;
513                             default:
514                                 break;
515                         }
516                     }
517                     break;
518 
519                 case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST:
520                     // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
521                     for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
522                         uint8_t       *des_element;
523                         uint8_t       *element;
524                         uint32_t       uuid;
525 
526                         if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
527 
528                         des_element = des_iterator_get_element(&des_list_it);
529                         des_iterator_init(&prot_it, des_element);
530                         element = des_iterator_get_element(&prot_it);
531 
532                         if (de_get_element_type(element) != DE_UUID) continue;
533 
534                         uuid = de_get_uuid32(element);
535                         des_iterator_next(&prot_it);
536                         // we assume that the even if there are both roles supported, remote device uses the same psm and avdtp version for both
537                         switch (uuid){
538                             case BLUETOOTH_PROTOCOL_L2CAP:
539                                 if (!des_iterator_has_more(&prot_it)) continue;
540                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->avdtp_l2cap_psm);
541                                 break;
542                             case BLUETOOTH_PROTOCOL_AVDTP:
543                                 if (!des_iterator_has_more(&prot_it)) continue;
544                                 de_element_get_uint16(des_iterator_get_element(&prot_it), &connection->avdtp_version);
545                                 log_info("avdtp version 0x%02x", connection->avdtp_version);
546                                 break;
547                             default:
548                                 break;
549                         }
550                     }
551                     break;
552 
553                 default:
554                     break;
555             }
556         }
557     } else {
558         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));
559     }
560 
561 }
562 
563 static void avdtp_finalize_connection(avdtp_connection_t * connection){
564     btstack_run_loop_remove_timer(&connection->retry_timer);
565     btstack_linked_list_remove(&connections, (btstack_linked_item_t*) connection);
566     btstack_memory_avdtp_connection_free(connection);
567 }
568 
569 static void avdtp_handle_sdp_query_failed(avdtp_connection_t * connection, uint8_t status){
570     switch (connection->state){
571         case AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SINK_COMPLETE:
572         case AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SOURCE_COMPLETE:
573             avdtp_signaling_emit_connection_established(connection->avdtp_cid, connection->remote_addr, status);
574             break;
575 
576         case AVDTP_SIGNALING_CONNECTION_OPENED:
577             // SDP query failed: try query that must be supported
578             connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CAPABILITIES;
579             avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
580             return;
581 
582         default:
583             btstack_assert(false);
584             break;
585     }
586     avdtp_finalize_connection(connection);
587     sdp_query_context_avdtp_cid = 0;
588     log_info("SDP query failed with status 0x%02x.", status);
589 }
590 
591 static void avdtp_handle_sdp_query_succeeded(avdtp_connection_t * connection){
592     log_info("avdtp_handle_sdp_query_succeeded: state %d", connection->state);
593 
594     switch (connection->state){
595         case AVDTP_SIGNALING_CONNECTION_OPENED:
596             if (connection->avdtp_version < 0x0103){
597                 connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CAPABILITIES;
598             } else {
599                 connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_ALL_CAPABILITIES;
600             }
601             avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
602             break;
603         default:
604             connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
605             l2cap_create_channel(avdtp_packet_handler, connection->remote_addr, connection->avdtp_l2cap_psm, l2cap_max_mtu(), NULL);
606             break;
607     }
608 }
609 
610 static void avdtp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
611     UNUSED(packet_type);
612     UNUSED(channel);
613     UNUSED(size);
614 
615     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(sdp_query_context_avdtp_cid);
616     if (!connection) {
617         log_error("SDP query, connection with 0x%02x cid not found", sdp_query_context_avdtp_cid);
618         return;
619     }
620 
621     uint8_t status = ERROR_CODE_SUCCESS;
622     switch (connection->state){
623         case AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SINK_COMPLETE:
624             switch (hci_event_packet_get_type(packet)){
625                 case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
626                     avdtp_handle_sdp_client_query_attribute_value(connection, packet);
627                     return;
628                 case SDP_EVENT_QUERY_COMPLETE:
629                     status = sdp_event_query_complete_get_status(packet);
630                     if (status != ERROR_CODE_SUCCESS) break;
631                     if (!connection->sink_supported) {
632                         status = ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
633                         break;
634                     }
635                     if (connection->avdtp_l2cap_psm == 0) {
636                         status = ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
637                         break;
638                     }
639                     break;
640                 default:
641                     btstack_assert(false);
642                     return;
643             }
644             break;
645         case AVDTP_SIGNALING_W4_SDP_QUERY_FOR_REMOTE_SOURCE_COMPLETE:
646             switch (hci_event_packet_get_type(packet)){
647                 case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
648                     avdtp_handle_sdp_client_query_attribute_value(connection, packet);
649                     return;
650                 case SDP_EVENT_QUERY_COMPLETE:
651                     status = sdp_event_query_complete_get_status(packet);
652                     if (status != ERROR_CODE_SUCCESS) break;
653                     if (!connection->source_supported) {
654                         status = ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
655                         break;
656                     }
657                     if (connection->avdtp_l2cap_psm == 0) {
658                         status = ERROR_CODE_UNSUPPORTED_FEATURE_OR_PARAMETER_VALUE;
659                         break;
660                     }
661                     break;
662                 default:
663                     btstack_assert(false);
664                     return;
665             }
666             break;
667 
668         case AVDTP_SIGNALING_CONNECTION_OPENED:
669             switch (hci_event_packet_get_type(packet)){
670                 case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
671                     avdtp_handle_sdp_client_query_attribute_value(connection, packet);
672                     return;
673                 case SDP_EVENT_QUERY_COMPLETE:
674                     status = sdp_event_query_complete_get_status(packet);
675                     break;
676                 default:
677                     btstack_assert(false);
678                     return;
679             }
680             break;
681 
682         default:
683             // bail out, we must have had an incoming connection in the meantime; just trigger next sdp query on complete
684             if (hci_event_packet_get_type(packet) == SDP_EVENT_QUERY_COMPLETE){
685                 (void) sdp_client_register_query_callback(&avdtp_handle_sdp_client_query_request);
686             }
687             return;
688     }
689 
690     if (status == ERROR_CODE_SUCCESS){
691         avdtp_handle_sdp_query_succeeded(connection);
692     } else {
693         avdtp_handle_sdp_query_failed(connection, status);
694     }
695 
696     // register the SDP Query request to check if there is another connection waiting for the query
697     // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
698     (void) sdp_client_register_query_callback(&avdtp_handle_sdp_client_query_request);
699 }
700 
701 static avdtp_connection_t * avdtp_handle_incoming_connection(avdtp_connection_t * connection, bd_addr_t event_addr, uint16_t local_cid){
702     if (connection == NULL){
703         uint16_t cid = avdtp_get_next_cid();
704         connection = avdtp_create_connection(event_addr, cid);
705     }
706 
707     if (connection) {
708         connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
709         connection->l2cap_signaling_cid = local_cid;
710         btstack_run_loop_remove_timer(&connection->retry_timer);
711     }
712     return connection;
713 }
714 
715 static void avdtp_retry_timer_timeout_handler(btstack_timer_source_t * timer){
716     uint16_t avdtp_cid = (uint16_t)(uintptr_t) btstack_run_loop_get_timer_context(timer);
717 
718     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
719     if (connection == NULL) return;
720 
721     if (connection->state == AVDTP_SIGNALING_CONNECTION_W2_L2CAP_RETRY){
722         connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
723         l2cap_create_channel(&avdtp_packet_handler, connection->remote_addr, connection->avdtp_l2cap_psm, l2cap_max_mtu(), NULL);
724     }
725 }
726 
727 static void avdtp_retry_timer_start(avdtp_connection_t * connection){
728     btstack_run_loop_set_timer_handler(&connection->retry_timer, avdtp_retry_timer_timeout_handler);
729     btstack_run_loop_set_timer_context(&connection->retry_timer, (void *)(uintptr_t)connection->avdtp_cid);
730 
731     // add some jitter/randomness to reconnect delay
732     uint32_t timeout = 100 + (btstack_run_loop_get_time_ms() & 0x7F);
733     btstack_run_loop_set_timer(&connection->retry_timer, timeout);
734     btstack_run_loop_add_timer(&connection->retry_timer);
735 }
736 
737 
738 void avdtp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
739     bd_addr_t event_addr;
740     uint16_t psm;
741     uint16_t local_cid;
742     uint8_t  status;
743     uint16_t l2cap_mtu;
744 
745     bool accept_streaming_connection;
746     bool outoing_signaling_active;
747     bool decline_connection;
748 
749     avdtp_stream_endpoint_t * stream_endpoint = NULL;
750     avdtp_connection_t * connection = NULL;
751 
752     switch (packet_type) {
753         case L2CAP_DATA_PACKET:
754             connection = avdtp_get_connection_for_l2cap_signaling_cid(channel);
755             if (connection){
756                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
757                 break;
758             }
759 
760             stream_endpoint = avdtp_get_stream_endpoint_for_l2cap_cid(channel);
761             if (!stream_endpoint){
762                 if (!connection) break;
763                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size);
764                 break;
765             }
766 
767             if (stream_endpoint->connection){
768                 if (channel == stream_endpoint->connection->l2cap_signaling_cid){
769                     handle_l2cap_data_packet_for_signaling_connection(stream_endpoint->connection, packet, size);
770                     break;
771                 }
772             }
773 
774             if (channel == stream_endpoint->l2cap_media_cid){
775                 btstack_assert(avdtp_sink_handle_media_data);
776                 (*avdtp_sink_handle_media_data)(avdtp_local_seid(stream_endpoint), packet, size);
777                 break;
778             }
779 
780             if (channel == stream_endpoint->l2cap_reporting_cid){
781                 log_info("L2CAP_DATA_PACKET for reporting: NOT IMPLEMENTED");
782             } else if (channel == stream_endpoint->l2cap_recovery_cid){
783                 log_info("L2CAP_DATA_PACKET for recovery: NOT IMPLEMENTED");
784             } else {
785                 log_error("avdtp packet handler L2CAP_DATA_PACKET: local cid 0x%02x not found", channel);
786             }
787             break;
788 
789         case HCI_EVENT_PACKET:
790             switch (hci_event_packet_get_type(packet)) {
791 
792                 case L2CAP_EVENT_INCOMING_CONNECTION:
793                     l2cap_event_incoming_connection_get_address(packet, event_addr);
794                     local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
795 
796                     outoing_signaling_active = false;
797                     accept_streaming_connection = false;
798 
799                     connection = avdtp_get_connection_for_bd_addr(event_addr);
800                     if (connection != NULL){
801                         switch (connection->state){
802                             case AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED:
803                             case AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED:
804                                 outoing_signaling_active = true;
805                                 connection->incoming_declined = true;
806                                 break;
807                             case AVDTP_SIGNALING_CONNECTION_OPENED:
808                                 outoing_signaling_active = true;
809                                 accept_streaming_connection = true;
810                                 break;
811                             default:
812                                 break;
813                         }
814                     }
815                     log_info("incoming: %s, outoing_signaling_active %d, accept_streaming_connection %d",
816                         bd_addr_to_str(event_addr), outoing_signaling_active, accept_streaming_connection);
817 
818                     decline_connection = outoing_signaling_active && !accept_streaming_connection;
819                     if (outoing_signaling_active == false){
820                         connection = avdtp_handle_incoming_connection(connection, event_addr, local_cid);
821                         if (connection == NULL){
822                             decline_connection = true;
823                         }
824                     } else if (accept_streaming_connection){
825                         if ((connection == NULL) || (connection->configuration_state != AVDTP_CONFIGURATION_STATE_REMOTE_CONFIGURED)) {
826                             decline_connection = true;
827                         } else {
828                             // now, we're only dealing with media connections that are created by remote side - we're acceptor here
829                             stream_endpoint = avdtp_get_stream_endpoint_with_seid(connection->acceptor_local_seid);
830                             if ((stream_endpoint == NULL) || (stream_endpoint->l2cap_media_cid != 0) ) {
831                                 decline_connection = true;
832                             }
833                         }
834                     }
835 
836                     if (decline_connection){
837                         l2cap_decline_connection(local_cid);
838                     } else {
839                         l2cap_accept_connection(local_cid);
840                     }
841                     break;
842 
843                 case L2CAP_EVENT_CHANNEL_OPENED:
844 
845                     psm = l2cap_event_channel_opened_get_psm(packet);
846                     if (psm != BLUETOOTH_PSM_AVDTP){
847                         log_info("Unexpected PSM - Not implemented yet, avdtp sink: L2CAP_EVENT_CHANNEL_OPENED ");
848                         return;
849                     }
850 
851                     status = l2cap_event_channel_opened_get_status(packet);
852                     // inform about new l2cap connection
853                     l2cap_event_channel_opened_get_address(packet, event_addr);
854                     local_cid = l2cap_event_channel_opened_get_local_cid(packet);
855                     l2cap_mtu = l2cap_event_channel_opened_get_remote_mtu(packet);
856                     connection = avdtp_get_connection_for_bd_addr(event_addr);
857                     if (connection == NULL){
858                         log_info("L2CAP_EVENT_CHANNEL_OPENED: no connection found for %s", bd_addr_to_str(event_addr));
859                         break;
860                     }
861 
862                     switch (connection->state){
863                         case AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED:
864                             switch (status){
865                                 case ERROR_CODE_SUCCESS:
866                                     connection->l2cap_signaling_cid = local_cid;
867                                     connection->incoming_declined = false;
868                                     connection->l2cap_mtu = l2cap_mtu;
869                                     connection->state = AVDTP_SIGNALING_CONNECTION_OPENED;
870                                     log_info("Connection opened l2cap_signaling_cid 0x%02x, avdtp_cid 0x%02x", connection->l2cap_signaling_cid, connection->avdtp_cid);
871                                     avdtp_signaling_emit_connection_established(connection->avdtp_cid, event_addr,
872                                                                                 status);
873                                     return;
874                                 case L2CAP_CONNECTION_RESPONSE_RESULT_REFUSED_RESOURCES:
875                                     if (connection->incoming_declined == true) {
876                                         log_info("Connection was declined, and the outgoing failed");
877                                         connection->state = AVDTP_SIGNALING_CONNECTION_W2_L2CAP_RETRY;
878                                         connection->incoming_declined = false;
879                                         avdtp_retry_timer_start(connection);
880                                         return;
881                                     }
882                                     break;
883                                 default:
884                                     log_info("Connection to %s failed. status code 0x%02x", bd_addr_to_str(event_addr), status);
885                                     break;
886                             }
887                             avdtp_signaling_emit_connection_established(connection->avdtp_cid, event_addr, status);
888                             avdtp_finalize_connection(connection);
889                             break;
890 
891                         case AVDTP_SIGNALING_CONNECTION_OPENED:
892                             stream_endpoint = avdtp_get_stream_endpoint_for_signaling_cid(connection->l2cap_signaling_cid);
893                             if (!stream_endpoint){
894                                 log_info("L2CAP_EVENT_CHANNEL_OPENED: stream_endpoint not found for signaling cid 0x%02x", connection->l2cap_signaling_cid);
895                                 return;
896                             }
897                             if (status != ERROR_CODE_SUCCESS){
898                                 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));
899                                 stream_endpoint->state = AVDTP_STREAM_ENDPOINT_IDLE;
900                                 avdtp_streaming_emit_connection_established(stream_endpoint, status);
901                                 break;
902                             }
903                             switch (stream_endpoint->state){
904                                 case AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_CONNECTED:
905                                     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_OPENED;
906                                     stream_endpoint->l2cap_media_cid = l2cap_event_channel_opened_get_local_cid(packet);
907                                     stream_endpoint->media_con_handle = l2cap_event_channel_opened_get_handle(packet);
908 
909                                     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));
910                                     avdtp_streaming_emit_connection_established(stream_endpoint, ERROR_CODE_SUCCESS);
911                                     break;
912                                 default:
913                                     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));
914                                     avdtp_streaming_emit_connection_established(stream_endpoint, ERROR_CODE_COMMAND_DISALLOWED);
915                                     break;
916                             }
917                             break;
918 
919                         default:
920                             log_info("L2CAP connection to %s ignored: status code 0x%02x, connection state %d", bd_addr_to_str(event_addr), status, connection->state);
921                             break;
922                     }
923                     break;
924 
925                 case L2CAP_EVENT_CHANNEL_CLOSED:
926                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
927                     stream_endpoint = avdtp_get_stream_endpoint_for_l2cap_cid(local_cid);
928                     connection = avdtp_get_connection_for_l2cap_signaling_cid(local_cid);
929 
930                     log_info("Received L2CAP_EVENT_CHANNEL_CLOSED, cid 0x%2x, connection %p, stream_endpoint %p", local_cid, connection, stream_endpoint);
931 
932                     if (stream_endpoint){
933                         if (stream_endpoint->l2cap_media_cid == local_cid){
934                             connection = stream_endpoint->connection;
935                             if (connection) {
936                                 avdtp_streaming_emit_connection_released(stream_endpoint,
937                                                                          connection->avdtp_cid,
938                                                                          avdtp_local_seid(stream_endpoint));
939                             }
940                             avdtp_reset_stream_endpoint(stream_endpoint);
941                             break;
942                         }
943                         if (stream_endpoint->l2cap_recovery_cid == local_cid){
944                             log_info("L2CAP_EVENT_CHANNEL_CLOSED recovery cid 0x%0x", local_cid);
945                             stream_endpoint->l2cap_recovery_cid = 0;
946                             break;
947                         }
948 
949                         if (stream_endpoint->l2cap_reporting_cid == local_cid){
950                             log_info("L2CAP_EVENT_CHANNEL_CLOSED reporting cid 0x%0x", local_cid);
951                             stream_endpoint->l2cap_reporting_cid = 0;
952                             break;
953                         }
954                     }
955 
956                     if (connection){
957                         btstack_linked_list_iterator_t it;
958                         btstack_linked_list_iterator_init(&it, avdtp_get_stream_endpoints());
959                         while (btstack_linked_list_iterator_has_next(&it)){
960                             stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
961                             if (stream_endpoint->connection == connection){
962                                 avdtp_reset_stream_endpoint(stream_endpoint);
963                             }
964                         }
965                         avdtp_signaling_emit_connection_released(connection->avdtp_cid);
966                         avdtp_finalize_connection(connection);
967                         break;
968                     }
969                     break;
970 
971                 case HCI_EVENT_DISCONNECTION_COMPLETE:
972                     break;
973 
974                 case L2CAP_EVENT_CAN_SEND_NOW:
975                     log_debug("avdtp_packet_handler, L2CAP_EVENT_CAN_SEND_NOW l2cap_cid 0x%02x", channel);
976                     connection = avdtp_get_connection_for_l2cap_signaling_cid(channel);
977                     if (!connection) {
978                         stream_endpoint = avdtp_get_stream_endpoint_for_l2cap_cid(channel);
979                         if (!stream_endpoint->connection) break;
980                         connection = stream_endpoint->connection;
981                     }
982                     avdtp_handle_can_send_now(connection, channel);
983                     break;
984                 default:
985                     log_info("Unknown HCI event type %02x", hci_event_packet_get_type(packet));
986                     break;
987             }
988             break;
989 
990         default:
991             // other packet type
992             break;
993     }
994 }
995 
996 uint8_t avdtp_disconnect(uint16_t avdtp_cid){
997     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
998     if (!connection) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
999 
1000     if (connection->state == AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED) return ERROR_CODE_SUCCESS;
1001 
1002     btstack_linked_list_iterator_t it;
1003     btstack_linked_list_iterator_init(&it, avdtp_get_stream_endpoints());
1004 
1005     while (btstack_linked_list_iterator_has_next(&it)){
1006         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
1007         if (stream_endpoint->connection != connection) continue;
1008 
1009         switch (stream_endpoint->state){
1010             case AVDTP_STREAM_ENDPOINT_OPENED:
1011             case AVDTP_STREAM_ENDPOINT_STREAMING:
1012                 stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_DISCONNECTED;
1013                 l2cap_disconnect(stream_endpoint->l2cap_media_cid, 0);
1014                 break;
1015             default:
1016                 break;
1017         }
1018     }
1019 
1020     connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED;
1021     l2cap_disconnect(connection->l2cap_signaling_cid, 0);
1022     return ERROR_CODE_SUCCESS;
1023 }
1024 
1025 uint8_t avdtp_open_stream(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid){
1026     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1027     if (!connection){
1028         log_error("avdtp_media_connect: no connection for signaling cid 0x%02x found", avdtp_cid);
1029         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1030     }
1031 
1032     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) {
1033         log_error("avdtp_media_connect: wrong connection state %d", connection->state);
1034         return ERROR_CODE_COMMAND_DISALLOWED;
1035     }
1036 
1037     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
1038     if (!stream_endpoint) {
1039         log_error("avdtp_media_connect: no stream_endpoint with seid %d found", local_seid);
1040         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1041     }
1042 
1043     if (stream_endpoint->remote_sep.seid != remote_seid){
1044         log_error("avdtp_media_connect: no remote sep with seid %d registered with the stream endpoint", remote_seid);
1045         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1046     }
1047 
1048     if (stream_endpoint->state < AVDTP_STREAM_ENDPOINT_CONFIGURED) return ERROR_CODE_COMMAND_DISALLOWED;
1049 
1050     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1051     connection->initiator_remote_seid = remote_seid;
1052     connection->initiator_local_seid = local_seid;
1053     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_OPEN_STREAM;
1054     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W2_REQUEST_OPEN_STREAM;
1055     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1056     return ERROR_CODE_SUCCESS;
1057 }
1058 
1059 uint8_t avdtp_start_stream(uint16_t avdtp_cid, uint8_t local_seid){
1060     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1061     if (!connection){
1062         log_error("avdtp_start_stream: no connection for signaling cid 0x%02x found", avdtp_cid);
1063         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1064     }
1065 
1066     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
1067     if (!stream_endpoint) {
1068         log_error("avdtp_start_stream: no stream_endpoint with seid %d found", local_seid);
1069         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1070     }
1071 
1072     if (stream_endpoint->l2cap_media_cid == 0){
1073         log_error("avdtp_start_stream: no media connection for stream_endpoint with seid %d found", local_seid);
1074         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1075     }
1076 
1077     if (!is_avdtp_remote_seid_registered(stream_endpoint)){
1078         log_error("avdtp_media_connect: no remote sep registered with the stream endpoint");
1079         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1080     }
1081 
1082     if (!is_avdtp_remote_seid_registered(stream_endpoint) || stream_endpoint->start_stream == 1){
1083         return ERROR_CODE_COMMAND_DISALLOWED;
1084     }
1085 
1086     stream_endpoint->start_stream = 1;
1087     connection->initiator_local_seid = local_seid;
1088     connection->initiator_remote_seid = stream_endpoint->remote_sep.seid;
1089     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1090     return ERROR_CODE_SUCCESS;
1091 }
1092 
1093 uint8_t avdtp_stop_stream(uint16_t avdtp_cid, uint8_t local_seid){
1094     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1095     if (!connection){
1096         log_error("avdtp_stop_stream: no connection for signaling cid 0x%02x found", avdtp_cid);
1097         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1098     }
1099 
1100     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
1101     if (!stream_endpoint) {
1102         log_error("avdtp_stop_stream: no stream_endpoint with seid %d found", local_seid);
1103         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1104     }
1105 
1106     if (stream_endpoint->l2cap_media_cid == 0){
1107         log_error("avdtp_stop_stream: no media connection for stream_endpoint with seid %d found", local_seid);
1108         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1109     }
1110 
1111     if (!is_avdtp_remote_seid_registered(stream_endpoint) || stream_endpoint->stop_stream){
1112         return ERROR_CODE_COMMAND_DISALLOWED;
1113     }
1114 
1115     stream_endpoint->stop_stream = 1;
1116     connection->initiator_local_seid = local_seid;
1117     connection->initiator_remote_seid = stream_endpoint->remote_sep.seid;
1118     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1119     return ERROR_CODE_SUCCESS;
1120 }
1121 
1122 uint8_t avdtp_abort_stream(uint16_t avdtp_cid, uint8_t local_seid){
1123     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1124     if (!connection){
1125         log_error("avdtp_abort_stream: no connection for signaling cid 0x%02x found", avdtp_cid);
1126         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1127     }
1128 
1129     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
1130     if (!stream_endpoint) {
1131         log_error("avdtp_abort_stream: no stream_endpoint with seid %d found", local_seid);
1132         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1133     }
1134 
1135     if (stream_endpoint->l2cap_media_cid == 0){
1136         log_error("avdtp_abort_stream: no media connection for stream_endpoint with seid %d found", local_seid);
1137         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1138     }
1139 
1140     if (!is_avdtp_remote_seid_registered(stream_endpoint) || stream_endpoint->abort_stream){
1141         return ERROR_CODE_COMMAND_DISALLOWED;
1142     }
1143 
1144     stream_endpoint->abort_stream = 1;
1145     connection->initiator_local_seid = local_seid;
1146     connection->initiator_remote_seid = stream_endpoint->remote_sep.seid;
1147     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1148     return ERROR_CODE_SUCCESS;
1149 }
1150 
1151 uint8_t avdtp_suspend_stream(uint16_t avdtp_cid, uint8_t local_seid){
1152     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1153     if (!connection){
1154         log_error("avdtp_suspend_stream: no connection for signaling cid 0x%02x found", avdtp_cid);
1155         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1156     }
1157     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_with_seid(local_seid);
1158     if (!stream_endpoint) {
1159         log_error("avdtp_suspend_stream: no stream_endpoint with seid %d found", local_seid);
1160         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1161     }
1162 
1163     if (stream_endpoint->l2cap_media_cid == 0){
1164         log_error("avdtp_suspend_stream: no media connection for stream_endpoint with seid %d found", local_seid);
1165         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1166     }
1167 
1168     if (!is_avdtp_remote_seid_registered(stream_endpoint) || stream_endpoint->suspend_stream){
1169         return ERROR_CODE_COMMAND_DISALLOWED;
1170     }
1171 
1172     stream_endpoint->suspend_stream = 1;
1173     connection->initiator_local_seid = local_seid;
1174     connection->initiator_remote_seid = stream_endpoint->remote_sep.seid;
1175     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1176     return ERROR_CODE_SUCCESS;
1177 }
1178 
1179 uint8_t avdtp_discover_stream_endpoints(uint16_t avdtp_cid){
1180     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1181     if (!connection){
1182         log_error("avdtp_discover_stream_endpoints: no connection for signaling cid 0x%02x found", avdtp_cid);
1183         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1184     }
1185     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1186         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1187         return ERROR_CODE_COMMAND_DISALLOWED;
1188     }
1189 
1190     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1191     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_DISCOVER_SEPS;
1192     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1193 }
1194 
1195 
1196 uint8_t avdtp_get_capabilities(uint16_t avdtp_cid, uint8_t remote_seid){
1197     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1198     if (!connection){
1199         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1200         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1201     }
1202     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1203         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1204         return ERROR_CODE_COMMAND_DISALLOWED;
1205     }
1206 
1207     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1208     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CAPABILITIES;
1209     connection->initiator_remote_seid = remote_seid;
1210     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1211 }
1212 
1213 
1214 uint8_t avdtp_get_all_capabilities(uint16_t avdtp_cid, uint8_t remote_seid){
1215     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1216     if (!connection){
1217         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1218         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1219     }
1220     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1221         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1222         return ERROR_CODE_COMMAND_DISALLOWED;
1223     }
1224 
1225     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1226     connection->initiator_remote_seid = remote_seid;
1227 
1228     if (connection->avdtp_version == 0){
1229         connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_SEND_SDP_QUERY_THEN_GET_ALL_CAPABILITIES;
1230         avdtp_handle_sdp_client_query_request.callback = &avdtp_handle_start_sdp_client_query;
1231         // ignore ERROR_CODE_COMMAND_DISALLOWED because in that case, we already have requested an SDP callback
1232         (void) sdp_client_register_query_callback(&avdtp_handle_sdp_client_query_request);
1233         return ERROR_CODE_SUCCESS;
1234     } else {
1235         // AVDTP version lower then 1.3 supports only get capabilities command
1236         if (connection->avdtp_version < 0x103){
1237             connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CAPABILITIES;
1238         } else {
1239             connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_ALL_CAPABILITIES;
1240         }
1241         return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1242     }
1243 }
1244 
1245 uint8_t avdtp_get_configuration(uint16_t avdtp_cid, uint8_t remote_seid){
1246     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1247     if (!connection){
1248         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1249         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1250     }
1251     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1252         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1253         return ERROR_CODE_COMMAND_DISALLOWED;
1254     }
1255 
1256     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1257     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CONFIGURATION;
1258     connection->initiator_remote_seid = remote_seid;
1259     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1260 }
1261 
1262 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){
1263     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1264     if (!connection){
1265         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1266         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1267     }
1268     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1269         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1270         log_error("connection in wrong state, %d, initiator state %d", connection->state, connection->initiator_connection_state);
1271         return ERROR_CODE_COMMAND_DISALLOWED;
1272     }
1273     if (connection->configuration_state != AVDTP_CONFIGURATION_STATE_IDLE){
1274         log_info("configuration already started, config state %u", connection->configuration_state);
1275         return ERROR_CODE_COMMAND_DISALLOWED;
1276     }
1277 
1278     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_for_seid(local_seid);
1279     if (!stream_endpoint) {
1280         log_error("No initiator stream endpoint for seid %d", local_seid);
1281         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1282     }
1283     if (stream_endpoint->state >= AVDTP_STREAM_ENDPOINT_CONFIGURED){
1284         log_error("Stream endpoint seid %d in wrong state %d", local_seid, stream_endpoint->state);
1285         return ERROR_CODE_COMMAND_DISALLOWED;
1286     }
1287 
1288     connection->active_stream_endpoint = (void*) stream_endpoint;
1289     connection->configuration_state = AVDTP_CONFIGURATION_STATE_LOCAL_INITIATED;
1290 
1291     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1292     connection->initiator_remote_seid = remote_seid;
1293     connection->initiator_local_seid = local_seid;
1294     stream_endpoint->remote_configuration_bitmap = configured_services_bitmap;
1295     stream_endpoint->remote_configuration = configuration;
1296     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_SET_CONFIGURATION;
1297 
1298     // cache media codec information for SBC
1299     stream_endpoint->media_codec_type = configuration.media_codec.media_codec_type;
1300     if (configuration.media_codec.media_codec_type == AVDTP_CODEC_SBC){
1301         stream_endpoint->media_type = configuration.media_codec.media_type;
1302         (void)memcpy(stream_endpoint->media_codec_sbc_info,
1303                      configuration.media_codec.media_codec_information, 4);
1304     }
1305     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1306 }
1307 
1308 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){
1309     avdtp_connection_t * connection = avdtp_get_connection_for_avdtp_cid(avdtp_cid);
1310     if (!connection){
1311         log_error("No connection for AVDTP cid 0x%02x found", avdtp_cid);
1312         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1313     }
1314     //TODO: if opened only app capabilities, enable reconfigure for not opened
1315     if ((connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) ||
1316         (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE)) {
1317         return ERROR_CODE_COMMAND_DISALLOWED;
1318     }
1319 
1320     avdtp_stream_endpoint_t * stream_endpoint = avdtp_get_stream_endpoint_for_seid(local_seid);
1321     if (!stream_endpoint) {
1322         log_error("avdtp_reconfigure: no initiator stream endpoint for seid %d", local_seid);
1323         return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1324     }
1325 
1326     if (!is_avdtp_remote_seid_registered(stream_endpoint)){
1327         log_error("avdtp_reconfigure: no associated remote sep");
1328         return ERROR_CODE_COMMAND_DISALLOWED;
1329     }
1330 
1331     connection->initiator_transaction_label= avdtp_get_next_transaction_label();
1332     connection->initiator_remote_seid = remote_seid;
1333     connection->initiator_local_seid = local_seid;
1334     stream_endpoint->remote_configuration_bitmap = configured_services_bitmap;
1335     stream_endpoint->remote_configuration = configuration;
1336     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_RECONFIGURE_STREAM_WITH_SEID;
1337     return avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
1338 }
1339 
1340 void    avdtp_set_preferred_sampling_frequeny(avdtp_stream_endpoint_t * stream_endpoint, uint32_t sampling_frequency){
1341     stream_endpoint->preferred_sampling_frequency = sampling_frequency;
1342 }
1343 
1344 uint8_t avdtp_choose_sbc_channel_mode(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_channel_mode_bitmap){
1345     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1346     uint8_t channel_mode_bitmap = (media_codec[0] & 0x0F) & remote_channel_mode_bitmap;
1347 
1348     uint8_t channel_mode = AVDTP_SBC_STEREO;
1349     if (channel_mode_bitmap & AVDTP_SBC_JOINT_STEREO){
1350         channel_mode = AVDTP_SBC_JOINT_STEREO;
1351     } else if (channel_mode_bitmap & AVDTP_SBC_STEREO){
1352         channel_mode = AVDTP_SBC_STEREO;
1353     } else if (channel_mode_bitmap & AVDTP_SBC_DUAL_CHANNEL){
1354         channel_mode = AVDTP_SBC_DUAL_CHANNEL;
1355     } else if (channel_mode_bitmap & AVDTP_SBC_MONO){
1356         channel_mode = AVDTP_SBC_MONO;
1357     }
1358     return channel_mode;
1359 }
1360 
1361 uint8_t avdtp_choose_sbc_allocation_method(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_allocation_method_bitmap){
1362     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1363     uint8_t allocation_method_bitmap = (media_codec[1] & 0x03) & remote_allocation_method_bitmap;
1364 
1365     uint8_t allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
1366     if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS){
1367         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
1368     } else if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_SNR){
1369         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_SNR;
1370     }
1371     return allocation_method;
1372 }
1373 
1374 uint8_t avdtp_stream_endpoint_seid(avdtp_stream_endpoint_t * stream_endpoint){
1375     if (!stream_endpoint) return 0;
1376     return stream_endpoint->sep.seid;
1377 }
1378 uint8_t avdtp_choose_sbc_subbands(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_subbands_bitmap){
1379     if (!stream_endpoint) return 0;
1380     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1381     uint8_t subbands_bitmap = ((media_codec[1] >> 2) & 0x03) & remote_subbands_bitmap;
1382 
1383     uint8_t subbands = AVDTP_SBC_SUBBANDS_8;
1384     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_8){
1385         subbands = AVDTP_SBC_SUBBANDS_8;
1386     } else if (subbands_bitmap & AVDTP_SBC_SUBBANDS_4){
1387         subbands = AVDTP_SBC_SUBBANDS_4;
1388     }
1389     return subbands;
1390 }
1391 
1392 uint8_t avdtp_choose_sbc_block_length(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_block_length_bitmap){
1393     if (!stream_endpoint) return 0;
1394     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1395     uint8_t block_length_bitmap = (media_codec[1] >> 4) & remote_block_length_bitmap;
1396 
1397     uint8_t block_length = AVDTP_SBC_BLOCK_LENGTH_16;
1398     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_16){
1399         block_length = AVDTP_SBC_BLOCK_LENGTH_16;
1400     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_12){
1401         block_length = AVDTP_SBC_BLOCK_LENGTH_12;
1402     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_8){
1403         block_length = AVDTP_SBC_BLOCK_LENGTH_8;
1404     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_4){
1405         block_length = AVDTP_SBC_BLOCK_LENGTH_4;
1406     }
1407     return block_length;
1408 }
1409 
1410 uint8_t avdtp_choose_sbc_sampling_frequency(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_sampling_frequency_bitmap){
1411     if (!stream_endpoint) return 0;
1412     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1413     uint8_t supported_sampling_frequency_bitmap = (media_codec[0] >> 4) & remote_sampling_frequency_bitmap;
1414 
1415     // use preferred sampling frequency if possible
1416     if ((stream_endpoint->preferred_sampling_frequency == 48000) && (supported_sampling_frequency_bitmap & AVDTP_SBC_48000)){
1417         return AVDTP_SBC_48000;
1418     }
1419     if ((stream_endpoint->preferred_sampling_frequency == 44100) && (supported_sampling_frequency_bitmap & AVDTP_SBC_44100)){
1420         return AVDTP_SBC_44100;
1421     }
1422     if ((stream_endpoint->preferred_sampling_frequency == 32000) && (supported_sampling_frequency_bitmap & AVDTP_SBC_32000)){
1423         return AVDTP_SBC_32000;
1424     }
1425     if ((stream_endpoint->preferred_sampling_frequency == 16000) && (supported_sampling_frequency_bitmap & AVDTP_SBC_16000)){
1426         return AVDTP_SBC_16000;
1427     }
1428 
1429     // otherwise, use highest available
1430     if (supported_sampling_frequency_bitmap & AVDTP_SBC_48000){
1431         return AVDTP_SBC_48000;
1432     }
1433     if (supported_sampling_frequency_bitmap & AVDTP_SBC_44100){
1434         return AVDTP_SBC_44100;
1435     }
1436     if (supported_sampling_frequency_bitmap & AVDTP_SBC_32000){
1437         return AVDTP_SBC_32000;
1438     }
1439     if (supported_sampling_frequency_bitmap & AVDTP_SBC_16000){
1440         return AVDTP_SBC_16000;
1441     }
1442     return AVDTP_SBC_44100; // some default
1443 }
1444 
1445 uint8_t avdtp_choose_sbc_max_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_max_bitpool_value){
1446     if (!stream_endpoint) return 0;
1447     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1448     return btstack_min(media_codec[3], remote_max_bitpool_value);
1449 }
1450 
1451 uint8_t avdtp_choose_sbc_min_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_min_bitpool_value){
1452     if (!stream_endpoint) return 0;
1453     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
1454     return btstack_max(media_codec[2], remote_min_bitpool_value);
1455 }
1456 
1457 uint8_t is_avdtp_remote_seid_registered(avdtp_stream_endpoint_t * stream_endpoint){
1458     if (!stream_endpoint) return 0;
1459     if (stream_endpoint->remote_sep.seid == 0) return 0;
1460     if (stream_endpoint->remote_sep.seid > 0x3E) return 0;
1461     return 1;
1462 }
1463 
1464 void avdtp_init(void){
1465     static bool l2cap_registered = false;
1466     if (!l2cap_registered){
1467         l2cap_registered = true;
1468         l2cap_register_service(&avdtp_packet_handler, BLUETOOTH_PSM_AVDTP, 0xffff, gap_get_security_level());
1469     }
1470 }
1471