xref: /btstack/src/classic/avdtp.c (revision 58c560219426df86e08670b9ca7d3d1f9979a6c1)
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 <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 
46 #include "btstack.h"
47 #include "avdtp.h"
48 #include "avdtp_util.h"
49 #include "avdtp_acceptor.h"
50 #include "avdtp_initiator.h"
51 
52 static int record_id = -1;
53 static uint8_t   attribute_value[1000];
54 static const unsigned int attribute_value_buffer_size = sizeof(attribute_value);
55 
56 typedef struct {
57     avdtp_connection_t * connection;
58     btstack_packet_handler_t avdtp_callback;
59     avdtp_sep_type_t query_role;
60     btstack_packet_handler_t packet_handler;
61 } avdtp_sdp_query_context_t;
62 
63 static avdtp_sdp_query_context_t sdp_query_context;
64 
65 static void (*handle_media_data)(avdtp_stream_endpoint_t * stream_endpoint, uint8_t *packet, uint16_t size);
66 static void avdtp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
67 
68 void avdtp_connect(bd_addr_t remote, avdtp_sep_type_t query_role, avdtp_context_t * avdtp_context){
69     sdp_query_context.connection = NULL;
70     avdtp_connection_t * connection = avdtp_connection_for_bd_addr(remote, avdtp_context);
71     if (!connection){
72         connection = avdtp_create_connection(remote, avdtp_context);
73     }
74     if (connection->state != AVDTP_SIGNALING_CONNECTION_IDLE) return;
75     connection->state = AVDTP_SIGNALING_W4_SDP_QUERY_COMPLETE;
76     sdp_query_context.connection = connection;
77     sdp_query_context.query_role = query_role;
78     sdp_query_context.avdtp_callback = avdtp_context->avdtp_callback;
79     sdp_query_context.packet_handler = avdtp_context->packet_handler;
80 
81     sdp_client_query_uuid16(&avdtp_handle_sdp_client_query_result, remote, BLUETOOTH_PROTOCOL_AVDTP);
82 }
83 
84 void avdtp_register_media_transport_category(avdtp_stream_endpoint_t * stream_endpoint){
85     if (!stream_endpoint){
86         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
87         return;
88     }
89     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_TRANSPORT, 1);
90     stream_endpoint->sep.registered_service_categories = bitmap;
91 }
92 
93 void avdtp_register_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
94     if (!stream_endpoint){
95         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
96         return;
97     }
98     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_REPORTING, 1);
99     stream_endpoint->sep.registered_service_categories = bitmap;
100 }
101 
102 void avdtp_register_delay_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
103     if (!stream_endpoint){
104         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
105         return;
106     }
107     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_DELAY_REPORTING, 1);
108     stream_endpoint->sep.registered_service_categories = bitmap;
109 }
110 
111 void avdtp_register_recovery_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t maximum_recovery_window_size, uint8_t maximum_number_media_packets){
112     if (!stream_endpoint){
113         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
114         return;
115     }
116     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_RECOVERY, 1);
117     stream_endpoint->sep.registered_service_categories = bitmap;
118     stream_endpoint->sep.capabilities.recovery.recovery_type = 0x01; // 0x01 = RFC2733
119     stream_endpoint->sep.capabilities.recovery.maximum_recovery_window_size = maximum_recovery_window_size;
120     stream_endpoint->sep.capabilities.recovery.maximum_number_media_packets = maximum_number_media_packets;
121 }
122 
123 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){
124     if (!stream_endpoint){
125         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
126         return;
127     }
128     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_CONTENT_PROTECTION, 1);
129     stream_endpoint->sep.registered_service_categories = bitmap;
130     stream_endpoint->sep.capabilities.content_protection.cp_type = cp_type;
131     stream_endpoint->sep.capabilities.content_protection.cp_type_value = cp_type_value;
132     stream_endpoint->sep.capabilities.content_protection.cp_type_value_len = cp_type_value_len;
133 }
134 
135 void avdtp_register_header_compression_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t back_ch, uint8_t media, uint8_t recovery){
136     if (!stream_endpoint){
137         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
138         return;
139     }
140     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_HEADER_COMPRESSION, 1);
141     stream_endpoint->sep.registered_service_categories = bitmap;
142     stream_endpoint->sep.capabilities.header_compression.back_ch = back_ch;
143     stream_endpoint->sep.capabilities.header_compression.media = media;
144     stream_endpoint->sep.capabilities.header_compression.recovery = recovery;
145 }
146 
147 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){
148     if (!stream_endpoint){
149         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
150         return;
151     }
152     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_CODEC, 1);
153     stream_endpoint->sep.registered_service_categories = bitmap;
154     stream_endpoint->sep.capabilities.media_codec.media_type = media_type;
155     stream_endpoint->sep.capabilities.media_codec.media_codec_type = media_codec_type;
156     stream_endpoint->sep.capabilities.media_codec.media_codec_information = media_codec_info;
157     stream_endpoint->sep.capabilities.media_codec.media_codec_information_len = media_codec_info_len;
158 }
159 
160 void avdtp_register_multiplexing_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t fragmentation){
161     if (!stream_endpoint){
162         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
163         return;
164     }
165     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MULTIPLEXING, 1);
166     stream_endpoint->sep.registered_service_categories = bitmap;
167     stream_endpoint->sep.capabilities.multiplexing_mode.fragmentation = fragmentation;
168 }
169 
170 
171 /* START: tracking can send now requests pro l2cap cid */
172 void avdtp_handle_can_send_now(avdtp_connection_t * connection, uint16_t l2cap_cid, avdtp_context_t * context){
173     if (connection->wait_to_send_acceptor){
174         connection->wait_to_send_acceptor = 0;
175         avdtp_acceptor_stream_config_subsm_run(connection, context);
176     } else if (connection->wait_to_send_initiator){
177         connection->wait_to_send_initiator = 0;
178         avdtp_initiator_stream_config_subsm_run(connection, context);
179     } else if (connection->wait_to_send_self){
180         connection->wait_to_send_self = 0;
181         if (connection->disconnect){
182             btstack_linked_list_iterator_t it;
183             btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
184             while (btstack_linked_list_iterator_has_next(&it)){
185                 avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
186                 if (stream_endpoint->connection == connection){
187                     if (stream_endpoint->state >= AVDTP_STREAM_ENDPOINT_OPENED && stream_endpoint->state != AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_DISCONNECTED){
188                         stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_DISCONNECTED;
189                         avdtp_request_can_send_now_self(connection, connection->l2cap_signaling_cid);
190                         l2cap_disconnect(stream_endpoint->l2cap_media_cid, 0);
191                         return;
192                     }
193                 }
194             }
195             connection->disconnect = 0;
196             connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED;
197             l2cap_disconnect(connection->l2cap_signaling_cid, 0);
198             return;
199         }
200     }
201 
202     // re-register
203     int more_to_send = connection->wait_to_send_acceptor || connection->wait_to_send_initiator || connection->wait_to_send_self;
204     if (more_to_send){
205         l2cap_request_can_send_now_event(l2cap_cid);
206     }
207 }
208 /* END: tracking can send now requests pro l2cap cid */
209 
210 avdtp_connection_t * avdtp_create_connection(bd_addr_t remote_addr, avdtp_context_t * context){
211     avdtp_connection_t * connection = btstack_memory_avdtp_connection_get();
212     memset(connection, 0, sizeof(avdtp_connection_t));
213     connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
214     connection->initiator_transaction_label++;
215     memcpy(connection->remote_addr, remote_addr, 6);
216     btstack_linked_list_add(&context->connections, (btstack_linked_item_t *) connection);
217     return connection;
218 }
219 
220 avdtp_stream_endpoint_t * avdtp_create_stream_endpoint(avdtp_sep_type_t sep_type, avdtp_media_type_t media_type, avdtp_context_t * context){
221     avdtp_stream_endpoint_t * stream_endpoint = btstack_memory_avdtp_stream_endpoint_get();
222     memset(stream_endpoint, 0, sizeof(avdtp_stream_endpoint_t));
223     context->stream_endpoints_id_counter++;
224     stream_endpoint->sep.seid = context->stream_endpoints_id_counter;
225     stream_endpoint->sep.media_type = media_type;
226     stream_endpoint->sep.type = sep_type;
227     btstack_linked_list_add(&context->stream_endpoints, (btstack_linked_item_t *) stream_endpoint);
228     return stream_endpoint;
229 }
230 
231 
232 static void handle_l2cap_data_packet_for_signaling_connection(avdtp_connection_t * connection, uint8_t *packet, uint16_t size, avdtp_context_t * context){
233     int offset = avdtp_read_signaling_header(&connection->signaling_packet, packet, size);
234     switch (connection->signaling_packet.message_type){
235         case AVDTP_CMD_MSG:
236             avdtp_acceptor_stream_config_subsm(connection, packet, size, offset, context);
237             break;
238         default:
239             avdtp_initiator_stream_config_subsm(connection, packet, size, offset, context);
240             break;
241     }
242 }
243 
244 static void stream_endpoint_state_machine(avdtp_connection_t * connection, avdtp_stream_endpoint_t * stream_endpoint, uint8_t packet_type, uint8_t event, uint8_t *packet, uint16_t size, avdtp_context_t * context){
245     uint16_t local_cid;
246     switch (packet_type){
247         case L2CAP_DATA_PACKET:{
248             int offset = avdtp_read_signaling_header(&connection->signaling_packet, packet, size);
249             if (connection->signaling_packet.message_type == AVDTP_CMD_MSG){
250                 avdtp_acceptor_stream_config_subsm(connection, packet, size, offset, context);
251             } else {
252                 avdtp_initiator_stream_config_subsm(connection, packet, size, offset, context);
253             }
254             break;
255         }
256         case HCI_EVENT_PACKET:
257             switch (event){
258                 case L2CAP_EVENT_CHANNEL_OPENED:
259                     if (stream_endpoint->l2cap_media_cid == 0){
260                         if (stream_endpoint->state != AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_CONNECTED) return;
261                         stream_endpoint->state = AVDTP_STREAM_ENDPOINT_OPENED;
262                         stream_endpoint->connection = connection;
263                         stream_endpoint->l2cap_media_cid = l2cap_event_channel_opened_get_local_cid(packet);
264                         stream_endpoint->media_con_handle = l2cap_event_channel_opened_get_handle(packet);
265                         log_info(" -> AVDTP_STREAM_ENDPOINT_OPENED, media con handle 0x%02x, l2cap_media_cid 0x%02x", stream_endpoint->media_con_handle, stream_endpoint->l2cap_media_cid);
266                         avdtp_streaming_emit_connection_established(context->avdtp_callback, connection->l2cap_signaling_cid, stream_endpoint->sep.seid, connection->remote_seps[stream_endpoint->remote_sep_index].seid, 0);
267                         break;
268                     }
269                     break;
270                 case L2CAP_EVENT_CHANNEL_CLOSED:
271                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
272                     if (stream_endpoint->l2cap_media_cid == local_cid){
273                         stream_endpoint->l2cap_media_cid = 0;
274                         log_info(" -> L2CAP_EVENT_CHANNEL_CLOSED: AVDTP_STREAM_ENDPOINT_IDLE");
275                         stream_endpoint->state = AVDTP_STREAM_ENDPOINT_IDLE;
276                         stream_endpoint->acceptor_config_state = AVDTP_ACCEPTOR_STREAM_CONFIG_IDLE;
277                         stream_endpoint->initiator_config_state = AVDTP_INITIATOR_STREAM_CONFIG_IDLE;
278                         stream_endpoint->remote_sep_index = 0;
279                         break;
280                     }
281                     if (stream_endpoint->l2cap_recovery_cid == local_cid){
282                         log_info(" -> L2CAP_EVENT_CHANNEL_CLOSED recovery cid 0x%0x", local_cid);
283                         stream_endpoint->l2cap_recovery_cid = 0;
284                         break;
285                     }
286 
287                     if (stream_endpoint->l2cap_reporting_cid == local_cid){
288                         log_info("L2CAP_EVENT_CHANNEL_CLOSED reporting cid 0x%0x", local_cid);
289                         stream_endpoint->l2cap_reporting_cid = 0;
290                         break;
291                     }
292                     break;
293                 default:
294                     break;
295             }
296             break;
297         default:
298             break;
299     }
300 }
301 
302 static void avdtp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
303     UNUSED(packet_type);
304     UNUSED(channel);
305     UNUSED(size);
306 
307     des_iterator_t des_list_it;
308     des_iterator_t prot_it;
309     uint16_t avdtp_l2cap_psm      = 0;
310     uint16_t avdtp_version        = 0;
311     // uint32_t avdtp_remote_uuid    = 0;
312 
313     if (!sdp_query_context.connection) return;
314 
315     switch (hci_event_packet_get_type(packet)){
316         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
317             // Handle new SDP record
318             if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id) {
319                 record_id = sdp_event_query_attribute_byte_get_record_id(packet);
320                 // log_info("SDP Record: Nr: %d", record_id);
321             }
322 
323             if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
324                 attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
325 
326                 if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
327 
328                     switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
329                         case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
330                             if (de_get_element_type(attribute_value) != DE_DES) break;
331                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
332                                 uint8_t * element = des_iterator_get_element(&des_list_it);
333                                 if (de_get_element_type(element) != DE_UUID) continue;
334                                 uint32_t uuid = de_get_uuid32(element);
335                                 switch (uuid){
336                                     case BLUETOOTH_SERVICE_CLASS_AUDIO_SOURCE:
337                                         if (sdp_query_context.query_role != AVDTP_SOURCE) {
338                                             sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
339                                             avdtp_signaling_emit_connection_established(sdp_query_context.avdtp_callback, sdp_query_context.connection->l2cap_signaling_cid, sdp_query_context.connection->remote_addr, 0);
340                                             break;
341                                         }
342                                         // log_info("SDP Attribute 0x%04x: AVDTP SOURCE protocol UUID: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
343                                         // avdtp_remote_uuid = uuid;
344                                         break;
345                                     case BLUETOOTH_SERVICE_CLASS_AUDIO_SINK:
346                                         if (sdp_query_context.query_role != AVDTP_SINK) {
347                                             sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
348                                             avdtp_signaling_emit_connection_established(sdp_query_context.avdtp_callback, sdp_query_context.connection->l2cap_signaling_cid, sdp_query_context.connection->remote_addr, 0);
349                                             break;
350                                         }
351                                         // log_info("SDP Attribute 0x%04x: AVDTP SINK protocol UUID: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
352                                         // avdtp_remote_uuid = uuid;
353                                         break;
354                                     default:
355                                         break;
356                                 }
357                             }
358                             break;
359 
360                         case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
361                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
362 
363                                 for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
364                                     uint8_t       *des_element;
365                                     uint8_t       *element;
366                                     uint32_t       uuid;
367 
368                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
369 
370                                     des_element = des_iterator_get_element(&des_list_it);
371                                     des_iterator_init(&prot_it, des_element);
372                                     element = des_iterator_get_element(&prot_it);
373 
374                                     if (de_get_element_type(element) != DE_UUID) continue;
375 
376                                     uuid = de_get_uuid32(element);
377                                     switch (uuid){
378                                         case BLUETOOTH_PROTOCOL_L2CAP:
379                                             if (!des_iterator_has_more(&prot_it)) continue;
380                                             des_iterator_next(&prot_it);
381                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &avdtp_l2cap_psm);
382                                             break;
383                                         case BLUETOOTH_PROTOCOL_AVDTP:
384                                             if (!des_iterator_has_more(&prot_it)) continue;
385                                             des_iterator_next(&prot_it);
386                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &avdtp_version);
387                                             break;
388                                         default:
389                                             break;
390                                     }
391                                 }
392                                 if (!avdtp_l2cap_psm) {
393                                     sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
394                                     avdtp_signaling_emit_connection_established(sdp_query_context.avdtp_callback, sdp_query_context.connection->l2cap_signaling_cid, sdp_query_context.connection->remote_addr, L2CAP_SERVICE_DOES_NOT_EXIST);
395                                     break;
396                                 }
397                                 sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
398                                 l2cap_create_channel(sdp_query_context.packet_handler, sdp_query_context.connection->remote_addr, avdtp_l2cap_psm, l2cap_max_mtu(), NULL);
399                             }
400                             break;
401                         default:
402                             break;
403                     }
404                 }
405             } else {
406                 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));
407             }
408             break;
409 
410         case SDP_EVENT_QUERY_COMPLETE:
411             log_info("General query done with status %d.", sdp_event_query_complete_get_status(packet));
412             break;
413     }
414 }
415 
416 
417 void avdtp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avdtp_context_t * context){
418     bd_addr_t event_addr;
419     hci_con_handle_t con_handle;
420     uint16_t psm;
421     uint16_t local_cid;
422     avdtp_stream_endpoint_t * stream_endpoint = NULL;
423     avdtp_connection_t * connection = NULL;
424     btstack_linked_list_t * avdtp_connections = &context->connections;
425     btstack_linked_list_t * stream_endpoints =  &context->stream_endpoints;
426     handle_media_data = context->handle_media_data;
427     // log_info("avdtp_packet_handler packet type %02x, event %02x ", packet_type, hci_event_packet_get_type(packet));
428     switch (packet_type) {
429         case L2CAP_DATA_PACKET:
430             connection = avdtp_connection_for_l2cap_signaling_cid(channel, context);
431             if (connection){
432                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size, context);
433                 break;
434             }
435 
436             stream_endpoint = avdtp_stream_endpoint_for_l2cap_cid(channel, context);
437             if (!stream_endpoint){
438                 if (!connection) break;
439                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size, context);
440                 break;
441             }
442 
443             if (channel == stream_endpoint->connection->l2cap_signaling_cid){
444                 stream_endpoint_state_machine(stream_endpoint->connection, stream_endpoint, L2CAP_DATA_PACKET, 0, packet, size, context);
445                 break;
446             }
447 
448             if (channel == stream_endpoint->l2cap_media_cid){
449                 (*handle_media_data)(stream_endpoint, packet, size);
450                 break;
451             }
452 
453             if (channel == stream_endpoint->l2cap_reporting_cid){
454                 // TODO
455                 log_info("L2CAP_DATA_PACKET for reporting: NOT IMPLEMENTED");
456             } else if (channel == stream_endpoint->l2cap_recovery_cid){
457                 // TODO
458                 log_info("L2CAP_DATA_PACKET for recovery: NOT IMPLEMENTED");
459             } else {
460                 log_error("avdtp packet handler L2CAP_DATA_PACKET: local cid 0x%02x not found", channel);
461             }
462             break;
463 
464         case HCI_EVENT_PACKET:
465             switch (hci_event_packet_get_type(packet)) {
466                 case L2CAP_EVENT_INCOMING_CONNECTION:
467                     l2cap_event_incoming_connection_get_address(packet, event_addr);
468                     local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
469 
470                     connection = avdtp_connection_for_bd_addr(event_addr, context);
471 
472                     if (!connection || connection->state == AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED){
473                         connection = avdtp_create_connection(event_addr, context);
474                         connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
475                         log_info("L2CAP_EVENT_INCOMING_CONNECTION, connection %p, state connection %d", connection, connection->state);
476                         l2cap_accept_connection(local_cid);
477                         break;
478                     }
479 
480                     stream_endpoint = avdtp_stream_endpoint_for_seid(connection->query_seid, context);
481                     if (!stream_endpoint) {
482                         log_info("L2CAP_EVENT_INCOMING_CONNECTION no streamendpoint found for seid %d", connection->query_seid);
483                         break;
484                     }
485 
486                     if (stream_endpoint->l2cap_media_cid == 0){
487                         if (stream_endpoint->state != AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_CONNECTED) break;
488                         l2cap_accept_connection(local_cid);
489                         break;
490                     }
491                     break;
492 
493                 case L2CAP_EVENT_CHANNEL_OPENED:
494                     // inform about new l2cap connection
495                     l2cap_event_channel_opened_get_address(packet, event_addr);
496                     if (l2cap_event_channel_opened_get_status(packet)){
497                         log_error("L2CAP connection to connection %s failed. status code 0x%02x",
498                             bd_addr_to_str(event_addr), l2cap_event_channel_opened_get_status(packet));
499                         break;
500                     }
501                     psm = l2cap_event_channel_opened_get_psm(packet);
502                     if (psm != BLUETOOTH_PROTOCOL_AVDTP){
503                         log_error("unexpected PSM - Not implemented yet, avdtp sink: L2CAP_EVENT_CHANNEL_OPENED");
504                         return;
505                     }
506 
507                     con_handle = l2cap_event_channel_opened_get_handle(packet);
508                     local_cid = l2cap_event_channel_opened_get_local_cid(packet);
509 
510                     log_info("L2CAP_EVENT_CHANNEL_OPENED: Channel successfully opened: %s, handle 0x%02x, psm 0x%02x, local cid 0x%02x, remote cid 0x%02x",
511                            bd_addr_to_str(event_addr), con_handle, psm, local_cid,  l2cap_event_channel_opened_get_remote_cid(packet));
512 
513                     if (psm != BLUETOOTH_PROTOCOL_AVDTP) break;
514 
515                     connection = avdtp_connection_for_bd_addr(event_addr, context);
516                     if (!connection) break;
517 
518                     if (connection->l2cap_signaling_cid == 0) {
519                         if (connection->state != AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED) break;
520                         connection->l2cap_signaling_cid = local_cid;
521                         connection->con_handle = con_handle;
522                         connection->query_seid = 0;
523                         connection->state = AVDTP_SIGNALING_CONNECTION_OPENED;
524                         log_info(" -> AVDTP_SIGNALING_CONNECTION_OPENED, connection %p", connection);
525                         avdtp_signaling_emit_connection_established(context->avdtp_callback, connection->l2cap_signaling_cid, event_addr, 0);
526                         break;
527                     }
528 
529                     stream_endpoint = avdtp_stream_endpoint_for_seid(connection->query_seid, context);
530                     if (!stream_endpoint){
531                         log_info("L2CAP_EVENT_CHANNEL_OPENED: stream_endpoint not found");
532                         return;
533                     }
534                     stream_endpoint_state_machine(connection, stream_endpoint, HCI_EVENT_PACKET, L2CAP_EVENT_CHANNEL_OPENED, packet, size, context);
535                     break;
536 
537                 case L2CAP_EVENT_CHANNEL_CLOSED:
538                     // data: event (8), len(8), channel (16)
539                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
540                     connection = avdtp_connection_for_l2cap_signaling_cid(local_cid, context);
541                     log_info(" -> L2CAP_EVENT_CHANNEL_CLOSED signaling cid 0x%0x", local_cid);
542 
543                     if (connection){
544                         log_info(" -> AVDTP_STREAM_ENDPOINT_IDLE, connection closed");
545                         btstack_linked_list_remove(avdtp_connections, (btstack_linked_item_t*) connection);
546                         btstack_linked_list_iterator_t it;
547                         btstack_linked_list_iterator_init(&it, stream_endpoints);
548                         while (btstack_linked_list_iterator_has_next(&it)){
549                             avdtp_stream_endpoint_t * _stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
550                             avdtp_initialize_stream_endpoint(_stream_endpoint);
551                         }
552                         break;
553                     }
554 
555                     stream_endpoint = avdtp_stream_endpoint_for_l2cap_cid(local_cid, context);
556                     if (!stream_endpoint) return;
557 
558                     stream_endpoint_state_machine(connection, stream_endpoint, HCI_EVENT_PACKET, L2CAP_EVENT_CHANNEL_CLOSED, packet, size, context);
559                     break;
560 
561                 case HCI_EVENT_DISCONNECTION_COMPLETE:
562                     break;
563 
564                 case L2CAP_EVENT_CAN_SEND_NOW:
565                     connection = avdtp_connection_for_l2cap_signaling_cid(channel, context);
566                     if (!connection) {
567                         stream_endpoint = avdtp_stream_endpoint_for_l2cap_cid(channel, context);
568                         if (!stream_endpoint->connection) break;
569                         connection = stream_endpoint->connection;
570                     }
571                     avdtp_handle_can_send_now(connection, channel, context);
572                     break;
573                 default:
574                     log_info("unknown HCI event type %02x", hci_event_packet_get_type(packet));
575                     break;
576             }
577             break;
578 
579         default:
580             // other packet type
581             break;
582     }
583 }
584 
585 void avdtp_disconnect(uint16_t avdtp_cid, avdtp_context_t * context){
586     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
587     if (!connection) return;
588     if (connection->state == AVDTP_SIGNALING_CONNECTION_IDLE) return;
589     if (connection->state == AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED) return;
590 
591     connection->disconnect = 1;
592     avdtp_request_can_send_now_self(connection, connection->l2cap_signaling_cid);
593 }
594 
595 void avdtp_open_stream(uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, avdtp_context_t * context){
596     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
597     if (!connection){
598         log_error("avdtp_media_connect: no connection for signaling cid 0x%02x found", avdtp_cid);
599         return;
600     }
601     if (avdtp_find_remote_sep(connection, acp_seid) == 0xFF){
602         log_error("avdtp_media_connect: no remote sep for seid %d found", acp_seid);
603         return;
604     }
605 
606     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) {
607         log_error("avdtp_media_connect: wrong connection state %d", connection->state);
608         return;
609     }
610 
611     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
612     if (!stream_endpoint) {
613         log_error("avdtp_media_connect: no stream_endpoint with seid %d found", int_seid);
614         return;
615     }
616 
617     if (stream_endpoint->state < AVDTP_STREAM_ENDPOINT_CONFIGURED) return;
618     if (stream_endpoint->remote_sep_index == AVDTP_INVALID_SEP_INDEX) return;
619 
620     connection->initiator_transaction_label++;
621     connection->acp_seid = acp_seid;
622     connection->int_seid = stream_endpoint->sep.seid;
623     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_OPEN_STREAM;
624     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W2_REQUEST_OPEN_STREAM;
625     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
626 }
627 
628 void avdtp_start_stream(uint8_t int_seid, avdtp_context_t * context){
629     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
630     if (!stream_endpoint) {
631         log_error("avdtp_start_stream: no stream_endpoint with seid %d found", int_seid);
632         return;
633     }
634     avdtp_connection_t * connection = stream_endpoint->connection;
635     if (!connection){
636         log_error("avdtp_start_stream: no connection for seid %d found",stream_endpoint->sep.seid);
637         return;
638     }
639 
640     if (stream_endpoint->remote_sep_index == AVDTP_INVALID_SEP_INDEX || stream_endpoint->start_stream) return;
641     stream_endpoint->start_stream = 1;
642     connection->int_seid = int_seid;
643     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
644 }
645 
646 void avdtp_stop_stream(uint8_t int_seid, avdtp_context_t * context){
647     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
648     if (!stream_endpoint) {
649         log_error("avdtp_stop_stream: no stream_endpoint with seid %d found", int_seid);
650         return;
651     }
652     avdtp_connection_t * connection = stream_endpoint->connection;
653     if (!connection){
654         log_error("avdtp_stop_stream: no connection for seid %d found",stream_endpoint->sep.seid);
655         return;
656     }
657     if (stream_endpoint->remote_sep_index == 0xFF || stream_endpoint->stop_stream) return;
658     stream_endpoint->stop_stream = 1;
659     connection->int_seid = int_seid;
660     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
661 }
662 
663 void avdtp_abort_stream(uint8_t int_seid, avdtp_context_t * context){
664     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
665     if (!stream_endpoint) {
666         log_error("avdtp_abort_stream: no stream_endpoint with seid %d found", int_seid);
667         return;
668     }
669     avdtp_connection_t * connection = stream_endpoint->connection;
670 
671     if (!connection){
672         log_error("avdtp_abort_stream: no connection for seid %d found",stream_endpoint->sep.seid);
673         return;
674     }
675     if (stream_endpoint->remote_sep_index == 0xFF || stream_endpoint->abort_stream) return;
676     stream_endpoint->abort_stream = 1;
677     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
678 }
679 
680 void avdtp_suspend_stream(uint8_t int_seid, avdtp_context_t * context){
681     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
682     if (!stream_endpoint) {
683         log_error("avdtp_abort_stream: no stream_endpoint with seid %d found", int_seid);
684         return;
685     }
686     avdtp_connection_t * connection = stream_endpoint->connection;
687     if (!connection){
688         log_error("avdtp_abort_stream: no connection for seid %d found",stream_endpoint->sep.seid);
689         return;
690     }
691     if (stream_endpoint->remote_sep_index == 0xFF || stream_endpoint->suspend_stream) return;
692     stream_endpoint->suspend_stream = 1;
693     connection->int_seid = int_seid;
694     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
695 }
696 
697 void avdtp_discover_stream_endpoints(uint16_t avdtp_cid, avdtp_context_t * context){
698     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
699     if (!connection){
700         log_error("avdtp_discover_stream_endpoints: no connection for signaling cid 0x%02x found", avdtp_cid);
701         return;
702     }
703     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
704 
705     switch (connection->initiator_connection_state){
706         case AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE:
707             connection->initiator_transaction_label++;
708             connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_DISCOVER_SEPS;
709             avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
710             break;
711         default:
712             log_error("avdtp_discover_stream_endpoints: wrong state");
713             break;
714     }
715 }
716 
717 
718 void avdtp_get_capabilities(uint16_t avdtp_cid, uint8_t acp_seid, avdtp_context_t * context){
719     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
720     if (!connection){
721         log_error("avdtp_get_capabilities: no connection for signaling cid 0x%02x found", avdtp_cid);
722         return;
723     }
724     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
725     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
726     connection->initiator_transaction_label++;
727     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CAPABILITIES;
728     connection->acp_seid = acp_seid;
729     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
730 }
731 
732 
733 void avdtp_get_all_capabilities(uint16_t avdtp_cid, uint8_t acp_seid, avdtp_context_t * context){
734     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
735     if (!connection){
736         log_error("avdtp_get_all_capabilities: no connection for signaling cid 0x%02x found", avdtp_cid);
737         return;
738     }
739     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
740     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
741     connection->initiator_transaction_label++;
742     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_ALL_CAPABILITIES;
743     connection->acp_seid = acp_seid;
744     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
745 }
746 
747 void avdtp_get_configuration(uint16_t avdtp_cid, uint8_t acp_seid, avdtp_context_t * context){
748     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
749     if (!connection){
750         log_error("avdtp_get_configuration: no connection for signaling cid 0x%02x found", avdtp_cid);
751         return;
752     }
753     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
754     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
755     connection->initiator_transaction_label++;
756     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CONFIGURATION;
757     connection->acp_seid = acp_seid;
758     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
759 }
760 
761 void avdtp_set_configuration(uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, uint16_t configured_services_bitmap, avdtp_capabilities_t configuration, avdtp_context_t * context){
762     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
763     if (!connection){
764         log_error("avdtp_set_configuration: no connection for signaling cid 0x%02x found", avdtp_cid);
765         return;
766     }
767     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
768     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
769 
770     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_for_seid(int_seid, context);
771     if (!stream_endpoint) {
772         log_error("avdtp_set_configuration: no initiator stream endpoint for seid %d", int_seid);
773         return;
774     }
775 
776     connection->initiator_transaction_label++;
777     connection->acp_seid = acp_seid;
778     connection->int_seid = int_seid;
779     stream_endpoint->remote_capabilities_bitmap = configured_services_bitmap;
780     stream_endpoint->remote_capabilities = configuration;
781     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_SET_CONFIGURATION;
782     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
783 }
784 
785 void avdtp_reconfigure(uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, uint16_t configured_services_bitmap, avdtp_capabilities_t configuration, avdtp_context_t * context){
786     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
787     if (!connection){
788         log_error("avdtp_reconfigure: no connection for signaling cid 0x%02x found", avdtp_cid);
789         return;
790     }
791     //TODO: if opened only app capabilities, enable reconfigure for not opened
792     if (connection->state < AVDTP_SIGNALING_CONNECTION_OPENED) return;
793     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
794 
795     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_for_seid(int_seid, context);
796     if (!stream_endpoint) {
797         log_error("avdtp_reconfigure: no initiator stream endpoint for seid %d", int_seid);
798         return;
799     }
800 
801     if (stream_endpoint->remote_sep_index == 0xFF){
802         log_error("avdtp_reconfigure: no associated remote sep");
803         return;
804     }
805 
806     connection->initiator_transaction_label++;
807     connection->acp_seid = acp_seid;
808     connection->int_seid = stream_endpoint->sep.seid;
809     stream_endpoint->remote_capabilities_bitmap = configured_services_bitmap;
810     stream_endpoint->remote_capabilities = configuration;
811     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_RECONFIGURE_STREAM_WITH_SEID;
812     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
813 }
814 
815 uint8_t avdtp_remote_seps_num(uint16_t avdtp_cid, avdtp_context_t * context){
816     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
817     if (!connection){
818         log_error("avdtp_suspend: no connection for signaling cid 0x%02x found", avdtp_cid);
819         return 0;
820     }
821     return connection->remote_seps_num;
822 }
823 
824 avdtp_sep_t * avdtp_remote_sep(uint16_t avdtp_cid, uint8_t index, avdtp_context_t * context){
825     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
826     if (!connection){
827         log_error("avdtp_suspend: no connection for signaling cid 0x%02x found", avdtp_cid);
828         return NULL;
829     }
830     return &connection->remote_seps[index];
831 }
832 
833 void avdtp_initialize_sbc_configuration_storage(avdtp_stream_endpoint_t * stream_endpoint, uint8_t * config_storage, uint16_t storage_size, uint8_t * packet, uint16_t packet_size){
834     UNUSED(packet_size);
835     if (storage_size < 4) {
836         log_error("storage must have 4 bytes");
837         return;
838     }
839     uint8_t sampling_frequency = avdtp_choose_sbc_sampling_frequency(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_sampling_frequency_bitmap(packet));
840     uint8_t channel_mode = avdtp_choose_sbc_channel_mode(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_channel_mode_bitmap(packet));
841     uint8_t block_length = avdtp_choose_sbc_block_length(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_block_length_bitmap(packet));
842     uint8_t subbands = avdtp_choose_sbc_subbands(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_subbands_bitmap(packet));
843 
844     uint8_t allocation_method = avdtp_choose_sbc_allocation_method(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_allocation_method_bitmap(packet));
845     uint8_t max_bitpool_value = avdtp_choose_sbc_max_bitpool_value(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_max_bitpool_value(packet));
846     uint8_t min_bitpool_value = avdtp_choose_sbc_min_bitpool_value(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_min_bitpool_value(packet));
847 
848     config_storage[0] = (sampling_frequency << 4) | channel_mode;
849     config_storage[1] = (block_length << 4) | (subbands << 2) | allocation_method;
850     config_storage[2] = min_bitpool_value;
851     config_storage[3] = max_bitpool_value;
852 
853     stream_endpoint->remote_configuration_bitmap = store_bit16(stream_endpoint->remote_configuration_bitmap, AVDTP_MEDIA_CODEC, 1);
854     stream_endpoint->remote_configuration.media_codec.media_type = AVDTP_AUDIO;
855     stream_endpoint->remote_configuration.media_codec.media_codec_type = AVDTP_CODEC_SBC;
856     stream_endpoint->remote_configuration.media_codec.media_codec_information_len = storage_size;
857     stream_endpoint->remote_configuration.media_codec.media_codec_information = config_storage;
858 }
859 
860 uint8_t avdtp_choose_sbc_channel_mode(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_channel_mode_bitmap){
861     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
862     uint8_t channel_mode_bitmap = (media_codec[0] & 0x0F) & remote_channel_mode_bitmap;
863 
864     uint8_t channel_mode = AVDTP_SBC_STEREO;
865     if (channel_mode_bitmap & AVDTP_SBC_JOINT_STEREO){
866         channel_mode = AVDTP_SBC_JOINT_STEREO;
867     } else if (channel_mode_bitmap & AVDTP_SBC_STEREO){
868         channel_mode = AVDTP_SBC_STEREO;
869     } else if (channel_mode_bitmap & AVDTP_SBC_DUAL_CHANNEL){
870         channel_mode = AVDTP_SBC_DUAL_CHANNEL;
871     } else if (channel_mode_bitmap & AVDTP_SBC_MONO){
872         channel_mode = AVDTP_SBC_MONO;
873     }
874     return channel_mode;
875 }
876 
877 uint8_t avdtp_choose_sbc_allocation_method(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_allocation_method_bitmap){
878     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
879     uint8_t allocation_method_bitmap = (media_codec[1] & 0x03) & remote_allocation_method_bitmap;
880 
881     uint8_t allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
882     if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS){
883         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
884     } else if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_SNR){
885         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_SNR;
886     }
887     return allocation_method;
888 }
889 
890 uint8_t avdtp_stream_endpoint_seid(avdtp_stream_endpoint_t * stream_endpoint){
891     if (!stream_endpoint) return 0;
892     return stream_endpoint->sep.seid;
893 }
894 uint8_t avdtp_choose_sbc_subbands(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_subbands_bitmap){
895     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
896     uint8_t subbands_bitmap = ((media_codec[1] >> 2) & 0x03) & remote_subbands_bitmap;
897 
898     uint8_t subbands = AVDTP_SBC_SUBBANDS_8;
899     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_8){
900         subbands = AVDTP_SBC_SUBBANDS_8;
901     } else if (subbands_bitmap & AVDTP_SBC_SUBBANDS_4){
902         subbands = AVDTP_SBC_SUBBANDS_4;
903     }
904     return subbands;
905 }
906 
907 uint8_t avdtp_choose_sbc_block_length(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_block_length_bitmap){
908     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
909     uint8_t block_length_bitmap = (media_codec[1] >> 4) & remote_block_length_bitmap;
910 
911     uint8_t block_length = AVDTP_SBC_BLOCK_LENGTH_16;
912     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_16){
913         block_length = AVDTP_SBC_BLOCK_LENGTH_16;
914     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_12){
915         block_length = AVDTP_SBC_BLOCK_LENGTH_12;
916     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_8){
917         block_length = AVDTP_SBC_BLOCK_LENGTH_8;
918     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_4){
919         block_length = AVDTP_SBC_BLOCK_LENGTH_4;
920     }
921     return block_length;
922 }
923 
924 uint8_t avdtp_choose_sbc_sampling_frequency(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_sampling_frequency_bitmap){
925     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
926     uint8_t sampling_frequency_bitmap = (media_codec[0] >> 4) & remote_sampling_frequency_bitmap;
927 
928     uint8_t sampling_frequency = AVDTP_SBC_44100;
929     if (sampling_frequency_bitmap & AVDTP_SBC_48000){
930         sampling_frequency = AVDTP_SBC_48000;
931     } else if (sampling_frequency_bitmap & AVDTP_SBC_44100){
932         sampling_frequency = AVDTP_SBC_44100;
933     } else if (sampling_frequency_bitmap & AVDTP_SBC_32000){
934         sampling_frequency = AVDTP_SBC_32000;
935     } else if (sampling_frequency_bitmap & AVDTP_SBC_16000){
936         sampling_frequency = AVDTP_SBC_16000;
937     }
938     return sampling_frequency;
939 }
940 
941 uint8_t avdtp_choose_sbc_max_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_max_bitpool_value){
942     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
943     return btstack_min(media_codec[3], remote_max_bitpool_value);
944 }
945 
946 uint8_t avdtp_choose_sbc_min_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_min_bitpool_value){
947     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
948     return btstack_max(media_codec[2], remote_min_bitpool_value);
949 }