xref: /btstack/src/classic/avdtp.c (revision 6b7adbe5dd4b0af3c7d33d07ce150d2f4a3a18e0)
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){
75         log_error("avdtp_connect: sink in wrong state,");
76         return;
77     }
78     connection->state = AVDTP_SIGNALING_W4_SDP_QUERY_COMPLETE;
79     sdp_query_context.connection = connection;
80     sdp_query_context.query_role = query_role;
81     sdp_query_context.avdtp_callback = avdtp_context->avdtp_callback;
82     sdp_query_context.packet_handler = avdtp_context->packet_handler;
83 
84     sdp_client_query_uuid16(&avdtp_handle_sdp_client_query_result, remote, BLUETOOTH_PROTOCOL_AVDTP);
85 }
86 
87 void avdtp_register_media_transport_category(avdtp_stream_endpoint_t * stream_endpoint){
88     if (!stream_endpoint){
89         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
90         return;
91     }
92     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_TRANSPORT, 1);
93     stream_endpoint->sep.registered_service_categories = bitmap;
94 }
95 
96 void avdtp_register_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
97     if (!stream_endpoint){
98         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
99         return;
100     }
101     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_REPORTING, 1);
102     stream_endpoint->sep.registered_service_categories = bitmap;
103 }
104 
105 void avdtp_register_delay_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
106     if (!stream_endpoint){
107         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
108         return;
109     }
110     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_DELAY_REPORTING, 1);
111     stream_endpoint->sep.registered_service_categories = bitmap;
112 }
113 
114 void avdtp_register_recovery_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t maximum_recovery_window_size, uint8_t maximum_number_media_packets){
115     if (!stream_endpoint){
116         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
117         return;
118     }
119     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_RECOVERY, 1);
120     stream_endpoint->sep.registered_service_categories = bitmap;
121     stream_endpoint->sep.capabilities.recovery.recovery_type = 0x01; // 0x01 = RFC2733
122     stream_endpoint->sep.capabilities.recovery.maximum_recovery_window_size = maximum_recovery_window_size;
123     stream_endpoint->sep.capabilities.recovery.maximum_number_media_packets = maximum_number_media_packets;
124 }
125 
126 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){
127     if (!stream_endpoint){
128         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
129         return;
130     }
131     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_CONTENT_PROTECTION, 1);
132     stream_endpoint->sep.registered_service_categories = bitmap;
133     stream_endpoint->sep.capabilities.content_protection.cp_type = cp_type;
134     stream_endpoint->sep.capabilities.content_protection.cp_type_value = cp_type_value;
135     stream_endpoint->sep.capabilities.content_protection.cp_type_value_len = cp_type_value_len;
136 }
137 
138 void avdtp_register_header_compression_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t back_ch, uint8_t media, uint8_t recovery){
139     if (!stream_endpoint){
140         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
141         return;
142     }
143     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_HEADER_COMPRESSION, 1);
144     stream_endpoint->sep.registered_service_categories = bitmap;
145     stream_endpoint->sep.capabilities.header_compression.back_ch = back_ch;
146     stream_endpoint->sep.capabilities.header_compression.media = media;
147     stream_endpoint->sep.capabilities.header_compression.recovery = recovery;
148 }
149 
150 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){
151     if (!stream_endpoint){
152         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
153         return;
154     }
155     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_CODEC, 1);
156     stream_endpoint->sep.registered_service_categories = bitmap;
157     stream_endpoint->sep.capabilities.media_codec.media_type = media_type;
158     stream_endpoint->sep.capabilities.media_codec.media_codec_type = media_codec_type;
159     stream_endpoint->sep.capabilities.media_codec.media_codec_information = media_codec_info;
160     stream_endpoint->sep.capabilities.media_codec.media_codec_information_len = media_codec_info_len;
161 }
162 
163 void avdtp_register_multiplexing_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t fragmentation){
164     if (!stream_endpoint){
165         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
166         return;
167     }
168     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MULTIPLEXING, 1);
169     stream_endpoint->sep.registered_service_categories = bitmap;
170     stream_endpoint->sep.capabilities.multiplexing_mode.fragmentation = fragmentation;
171 }
172 
173 
174 /* START: tracking can send now requests pro l2cap cid */
175 void avdtp_handle_can_send_now(avdtp_connection_t * connection, uint16_t l2cap_cid, avdtp_context_t * context){
176     if (connection->wait_to_send_acceptor){
177         connection->wait_to_send_acceptor = 0;
178         avdtp_acceptor_stream_config_subsm_run(connection, context);
179     } else if (connection->wait_to_send_initiator){
180         connection->wait_to_send_initiator = 0;
181         avdtp_initiator_stream_config_subsm_run(connection, context);
182     } else if (connection->wait_to_send_self){
183         connection->wait_to_send_self = 0;
184         if (connection->disconnect){
185             btstack_linked_list_iterator_t it;
186             btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
187             while (btstack_linked_list_iterator_has_next(&it)){
188                 avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
189                 if (stream_endpoint->connection == connection){
190                     if (stream_endpoint->state >= AVDTP_STREAM_ENDPOINT_OPENED && stream_endpoint->state != AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_DISCONNECTED){
191                         stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_DISCONNECTED;
192                         avdtp_request_can_send_now_self(connection, connection->l2cap_signaling_cid);
193                         l2cap_disconnect(stream_endpoint->l2cap_media_cid, 0);
194                         return;
195                     }
196                 }
197             }
198             connection->disconnect = 0;
199             connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED;
200             l2cap_disconnect(connection->l2cap_signaling_cid, 0);
201             return;
202         }
203     }
204 
205     // re-register
206     int more_to_send = connection->wait_to_send_acceptor || connection->wait_to_send_initiator || connection->wait_to_send_self;
207     if (more_to_send){
208         l2cap_request_can_send_now_event(l2cap_cid);
209     }
210 }
211 /* END: tracking can send now requests pro l2cap cid */
212 
213 avdtp_connection_t * avdtp_create_connection(bd_addr_t remote_addr, avdtp_context_t * context){
214     avdtp_connection_t * connection = btstack_memory_avdtp_connection_get();
215     memset(connection, 0, sizeof(avdtp_connection_t));
216     connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
217     connection->initiator_transaction_label++;
218     memcpy(connection->remote_addr, remote_addr, 6);
219     btstack_linked_list_add(&context->connections, (btstack_linked_item_t *) connection);
220     return connection;
221 }
222 
223 avdtp_stream_endpoint_t * avdtp_create_stream_endpoint(avdtp_sep_type_t sep_type, avdtp_media_type_t media_type, avdtp_context_t * context){
224     avdtp_stream_endpoint_t * stream_endpoint = btstack_memory_avdtp_stream_endpoint_get();
225     memset(stream_endpoint, 0, sizeof(avdtp_stream_endpoint_t));
226     context->stream_endpoints_id_counter++;
227     stream_endpoint->sep.seid = context->stream_endpoints_id_counter;
228     stream_endpoint->sep.media_type = media_type;
229     stream_endpoint->sep.type = sep_type;
230     btstack_linked_list_add(&context->stream_endpoints, (btstack_linked_item_t *) stream_endpoint);
231     return stream_endpoint;
232 }
233 
234 
235 static void handle_l2cap_data_packet_for_signaling_connection(avdtp_connection_t * connection, uint8_t *packet, uint16_t size, avdtp_context_t * context){
236     int offset = avdtp_read_signaling_header(&connection->signaling_packet, packet, size);
237     switch (connection->signaling_packet.message_type){
238         case AVDTP_CMD_MSG:
239             avdtp_acceptor_stream_config_subsm(connection, packet, size, offset, context);
240             break;
241         default:
242             avdtp_initiator_stream_config_subsm(connection, packet, size, offset, context);
243             break;
244     }
245 }
246 
247 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){
248     uint16_t local_cid;
249     switch (packet_type){
250         case L2CAP_DATA_PACKET:{
251             int offset = avdtp_read_signaling_header(&connection->signaling_packet, packet, size);
252             if (connection->signaling_packet.message_type == AVDTP_CMD_MSG){
253                 avdtp_acceptor_stream_config_subsm(connection, packet, size, offset, context);
254             } else {
255                 avdtp_initiator_stream_config_subsm(connection, packet, size, offset, context);
256             }
257             break;
258         }
259         case HCI_EVENT_PACKET:
260             switch (event){
261                 case L2CAP_EVENT_CHANNEL_OPENED:
262                     if (stream_endpoint->l2cap_media_cid == 0){
263                         if (stream_endpoint->state != AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_CONNECTED) return;
264                         stream_endpoint->state = AVDTP_STREAM_ENDPOINT_OPENED;
265                         stream_endpoint->connection = connection;
266                         stream_endpoint->l2cap_media_cid = l2cap_event_channel_opened_get_local_cid(packet);
267                         stream_endpoint->media_con_handle = l2cap_event_channel_opened_get_handle(packet);
268                         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);
269                         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);
270                         break;
271                     }
272                     break;
273                 case L2CAP_EVENT_CHANNEL_CLOSED:
274                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
275                     if (stream_endpoint->l2cap_media_cid == local_cid){
276                         stream_endpoint->l2cap_media_cid = 0;
277                         log_info(" -> L2CAP_EVENT_CHANNEL_CLOSED: AVDTP_STREAM_ENDPOINT_IDLE");
278                         stream_endpoint->state = AVDTP_STREAM_ENDPOINT_IDLE;
279                         stream_endpoint->acceptor_config_state = AVDTP_ACCEPTOR_STREAM_CONFIG_IDLE;
280                         stream_endpoint->initiator_config_state = AVDTP_INITIATOR_STREAM_CONFIG_IDLE;
281                         stream_endpoint->remote_sep_index = 0;
282                         break;
283                     }
284                     if (stream_endpoint->l2cap_recovery_cid == local_cid){
285                         log_info(" -> L2CAP_EVENT_CHANNEL_CLOSED recovery cid 0x%0x", local_cid);
286                         stream_endpoint->l2cap_recovery_cid = 0;
287                         break;
288                     }
289 
290                     if (stream_endpoint->l2cap_reporting_cid == local_cid){
291                         log_info("L2CAP_EVENT_CHANNEL_CLOSED reporting cid 0x%0x", local_cid);
292                         stream_endpoint->l2cap_reporting_cid = 0;
293                         break;
294                     }
295                     break;
296                 default:
297                     break;
298             }
299             break;
300         default:
301             break;
302     }
303 }
304 
305 static void avdtp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
306     UNUSED(packet_type);
307     UNUSED(channel);
308     UNUSED(size);
309 
310     des_iterator_t des_list_it;
311     des_iterator_t prot_it;
312     uint16_t avdtp_l2cap_psm      = 0;
313     uint16_t avdtp_version        = 0;
314     // uint32_t avdtp_remote_uuid    = 0;
315 
316     if (!sdp_query_context.connection) return;
317 
318     switch (hci_event_packet_get_type(packet)){
319         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
320             // Handle new SDP record
321             if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id) {
322                 record_id = sdp_event_query_attribute_byte_get_record_id(packet);
323                 // log_info("SDP Record: Nr: %d", record_id);
324             }
325 
326             if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
327                 attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
328 
329                 if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
330 
331                     switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
332                         case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
333                             if (de_get_element_type(attribute_value) != DE_DES) break;
334                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
335                                 uint8_t * element = des_iterator_get_element(&des_list_it);
336                                 if (de_get_element_type(element) != DE_UUID) continue;
337                                 uint32_t uuid = de_get_uuid32(element);
338                                 switch (uuid){
339                                     case BLUETOOTH_SERVICE_CLASS_AUDIO_SOURCE:
340                                         if (sdp_query_context.query_role != AVDTP_SOURCE) {
341                                             sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
342                                             avdtp_signaling_emit_connection_established(sdp_query_context.avdtp_callback, sdp_query_context.connection->l2cap_signaling_cid, sdp_query_context.connection->remote_addr, SDP_SERVICE_NOT_FOUND);
343                                             break;
344                                         }
345                                         // log_info("SDP Attribute 0x%04x: AVDTP SOURCE protocol UUID: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
346                                         // avdtp_remote_uuid = uuid;
347                                         break;
348                                     case BLUETOOTH_SERVICE_CLASS_AUDIO_SINK:
349                                         if (sdp_query_context.query_role != AVDTP_SINK) {
350                                             sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
351                                             avdtp_signaling_emit_connection_established(sdp_query_context.avdtp_callback, sdp_query_context.connection->l2cap_signaling_cid, sdp_query_context.connection->remote_addr, SDP_SERVICE_NOT_FOUND);
352                                             break;
353                                         }
354                                         // log_info("SDP Attribute 0x%04x: AVDTP SINK protocol UUID: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
355                                         // avdtp_remote_uuid = uuid;
356                                         break;
357                                     default:
358                                         break;
359                                 }
360                             }
361                             break;
362 
363                         case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
364                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
365 
366                                 for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
367                                     uint8_t       *des_element;
368                                     uint8_t       *element;
369                                     uint32_t       uuid;
370 
371                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
372 
373                                     des_element = des_iterator_get_element(&des_list_it);
374                                     des_iterator_init(&prot_it, des_element);
375                                     element = des_iterator_get_element(&prot_it);
376 
377                                     if (de_get_element_type(element) != DE_UUID) continue;
378 
379                                     uuid = de_get_uuid32(element);
380                                     switch (uuid){
381                                         case BLUETOOTH_PROTOCOL_L2CAP:
382                                             if (!des_iterator_has_more(&prot_it)) continue;
383                                             des_iterator_next(&prot_it);
384                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &avdtp_l2cap_psm);
385                                             break;
386                                         case BLUETOOTH_PROTOCOL_AVDTP:
387                                             if (!des_iterator_has_more(&prot_it)) continue;
388                                             des_iterator_next(&prot_it);
389                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &avdtp_version);
390                                             break;
391                                         default:
392                                             break;
393                                     }
394                                 }
395                                 if (!avdtp_l2cap_psm) {
396                                     sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
397                                     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);
398                                     break;
399                                 }
400                                 sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
401                                 l2cap_create_channel(sdp_query_context.packet_handler, sdp_query_context.connection->remote_addr, avdtp_l2cap_psm, l2cap_max_mtu(), NULL);
402                             }
403                             break;
404                         default:
405                             break;
406                     }
407                 }
408             } else {
409                 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));
410             }
411             break;
412 
413         case SDP_EVENT_QUERY_COMPLETE:
414             log_info("General query done with status %d.", sdp_event_query_complete_get_status(packet));
415             break;
416     }
417 }
418 
419 
420 void avdtp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avdtp_context_t * context){
421     bd_addr_t event_addr;
422     hci_con_handle_t con_handle;
423     uint16_t psm;
424     uint16_t local_cid;
425     avdtp_stream_endpoint_t * stream_endpoint = NULL;
426     avdtp_connection_t * connection = NULL;
427     btstack_linked_list_t * avdtp_connections = &context->connections;
428     btstack_linked_list_t * stream_endpoints =  &context->stream_endpoints;
429     handle_media_data = context->handle_media_data;
430     // log_info("avdtp_packet_handler packet type %02x, event %02x ", packet_type, hci_event_packet_get_type(packet));
431     switch (packet_type) {
432         case L2CAP_DATA_PACKET:
433             connection = avdtp_connection_for_l2cap_signaling_cid(channel, context);
434             if (connection){
435                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size, context);
436                 break;
437             }
438 
439             stream_endpoint = avdtp_stream_endpoint_for_l2cap_cid(channel, context);
440             if (!stream_endpoint){
441                 if (!connection) break;
442                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size, context);
443                 break;
444             }
445 
446             if (channel == stream_endpoint->connection->l2cap_signaling_cid){
447                 stream_endpoint_state_machine(stream_endpoint->connection, stream_endpoint, L2CAP_DATA_PACKET, 0, packet, size, context);
448                 break;
449             }
450 
451             if (channel == stream_endpoint->l2cap_media_cid){
452                 if (handle_media_data){
453                     (*handle_media_data)(stream_endpoint, packet, size);
454                 }
455                 break;
456             }
457 
458             if (channel == stream_endpoint->l2cap_reporting_cid){
459                 // TODO
460                 log_info("L2CAP_DATA_PACKET for reporting: NOT IMPLEMENTED");
461             } else if (channel == stream_endpoint->l2cap_recovery_cid){
462                 // TODO
463                 log_info("L2CAP_DATA_PACKET for recovery: NOT IMPLEMENTED");
464             } else {
465                 log_error("avdtp packet handler L2CAP_DATA_PACKET: local cid 0x%02x not found", channel);
466             }
467             break;
468 
469         case HCI_EVENT_PACKET:
470             switch (hci_event_packet_get_type(packet)) {
471                 case L2CAP_EVENT_INCOMING_CONNECTION:
472                     l2cap_event_incoming_connection_get_address(packet, event_addr);
473                     local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
474 
475                     connection = avdtp_connection_for_bd_addr(event_addr, context);
476 
477                     if (!connection || connection->state == AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED){
478                         connection = avdtp_create_connection(event_addr, context);
479                         connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
480                         log_info("L2CAP_EVENT_INCOMING_CONNECTION, connection %p, state connection %d", connection, connection->state);
481                         l2cap_accept_connection(local_cid);
482                         break;
483                     }
484 
485                     stream_endpoint = avdtp_stream_endpoint_for_seid(connection->query_seid, context);
486                     if (!stream_endpoint) {
487                         log_info("L2CAP_EVENT_INCOMING_CONNECTION no streamendpoint found for seid %d", connection->query_seid);
488                         break;
489                     }
490 
491                     if (stream_endpoint->l2cap_media_cid == 0){
492                         if (stream_endpoint->state != AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_CONNECTED) break;
493                         l2cap_accept_connection(local_cid);
494                         break;
495                     }
496                     break;
497 
498                 case L2CAP_EVENT_CHANNEL_OPENED:
499                     // inform about new l2cap connection
500                     l2cap_event_channel_opened_get_address(packet, event_addr);
501                     local_cid = l2cap_event_channel_opened_get_local_cid(packet);
502                     if (l2cap_event_channel_opened_get_status(packet)){
503                         avdtp_signaling_emit_connection_established(context->avdtp_callback, connection->l2cap_signaling_cid, event_addr, l2cap_event_channel_opened_get_status(packet));
504                         log_error("L2CAP connection to connection %s failed. status code 0x%02x",
505                             bd_addr_to_str(event_addr), l2cap_event_channel_opened_get_status(packet));
506                         break;
507                     }
508                     psm = l2cap_event_channel_opened_get_psm(packet);
509                     if (psm != BLUETOOTH_PROTOCOL_AVDTP){
510                         log_error("unexpected PSM - Not implemented yet, avdtp sink: L2CAP_EVENT_CHANNEL_OPENED");
511                         return;
512                     }
513 
514                     con_handle = l2cap_event_channel_opened_get_handle(packet);
515 
516                     log_info("L2CAP_EVENT_CHANNEL_OPENED: Channel successfully opened: %s, handle 0x%02x, psm 0x%02x, local cid 0x%02x, remote cid 0x%02x",
517                            bd_addr_to_str(event_addr), con_handle, psm, local_cid,  l2cap_event_channel_opened_get_remote_cid(packet));
518 
519                     if (psm != BLUETOOTH_PROTOCOL_AVDTP) break;
520 
521                     connection = avdtp_connection_for_bd_addr(event_addr, context);
522                     if (!connection) break;
523 
524                     if (connection->l2cap_signaling_cid == 0) {
525                         if (connection->state != AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED) break;
526                         connection->l2cap_signaling_cid = local_cid;
527                         connection->con_handle = con_handle;
528                         connection->query_seid = 0;
529                         connection->state = AVDTP_SIGNALING_CONNECTION_OPENED;
530                         log_info(" -> AVDTP_SIGNALING_CONNECTION_OPENED, connection %p", connection);
531                         avdtp_signaling_emit_connection_established(context->avdtp_callback, connection->l2cap_signaling_cid, event_addr, 0);
532                         break;
533                     }
534 
535                     stream_endpoint = avdtp_stream_endpoint_for_seid(connection->query_seid, context);
536                     if (!stream_endpoint){
537                         log_info("L2CAP_EVENT_CHANNEL_OPENED: stream_endpoint not found");
538                         return;
539                     }
540                     stream_endpoint_state_machine(connection, stream_endpoint, HCI_EVENT_PACKET, L2CAP_EVENT_CHANNEL_OPENED, packet, size, context);
541                     break;
542 
543                 case L2CAP_EVENT_CHANNEL_CLOSED:
544                     // data: event (8), len(8), channel (16)
545                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
546                     connection = avdtp_connection_for_l2cap_signaling_cid(local_cid, context);
547                     log_info(" -> L2CAP_EVENT_CHANNEL_CLOSED signaling cid 0x%0x", local_cid);
548 
549                     stream_endpoint = avdtp_stream_endpoint_for_l2cap_cid(local_cid, context);
550                     if (stream_endpoint){
551                         stream_endpoint_state_machine(connection, stream_endpoint, HCI_EVENT_PACKET, L2CAP_EVENT_CHANNEL_CLOSED, packet, size, context);
552                         break;
553                     }
554 
555                     if (connection){
556                         log_info(" -> AVDTP_STREAM_ENDPOINT_IDLE, connection closed");
557                         btstack_linked_list_remove(avdtp_connections, (btstack_linked_item_t*) connection);
558 
559                         btstack_linked_list_iterator_t it;
560                         btstack_linked_list_iterator_init(&it, stream_endpoints);
561                         while (btstack_linked_list_iterator_has_next(&it)){
562                             avdtp_stream_endpoint_t * _stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
563 
564                             if (_stream_endpoint->connection == connection){
565                                 avdtp_initialize_stream_endpoint(_stream_endpoint);
566                             }
567                         }
568                         btstack_memory_avdtp_connection_free(connection);
569                         break;
570                     }
571                     break;
572 
573                 case HCI_EVENT_DISCONNECTION_COMPLETE:
574                     break;
575 
576                 case L2CAP_EVENT_CAN_SEND_NOW:
577                     connection = avdtp_connection_for_l2cap_signaling_cid(channel, context);
578                     if (!connection) {
579                         stream_endpoint = avdtp_stream_endpoint_for_l2cap_cid(channel, context);
580                         if (!stream_endpoint->connection) break;
581                         connection = stream_endpoint->connection;
582                     }
583                     avdtp_handle_can_send_now(connection, channel, context);
584                     break;
585                 default:
586                     log_info("unknown HCI event type %02x", hci_event_packet_get_type(packet));
587                     break;
588             }
589             break;
590 
591         default:
592             // other packet type
593             break;
594     }
595 }
596 
597 void avdtp_disconnect(uint16_t avdtp_cid, avdtp_context_t * context){
598     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
599     if (!connection) return;
600     if (connection->state == AVDTP_SIGNALING_CONNECTION_IDLE) return;
601     if (connection->state == AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED) return;
602 
603     connection->disconnect = 1;
604     avdtp_request_can_send_now_self(connection, connection->l2cap_signaling_cid);
605 }
606 
607 void avdtp_open_stream(uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, avdtp_context_t * context){
608     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
609     if (!connection){
610         log_error("avdtp_media_connect: no connection for signaling cid 0x%02x found", avdtp_cid);
611         return;
612     }
613     if (avdtp_find_remote_sep(connection, acp_seid) == 0xFF){
614         log_error("avdtp_media_connect: no remote sep for seid %d found", acp_seid);
615         return;
616     }
617 
618     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) {
619         log_error("avdtp_media_connect: wrong connection state %d", connection->state);
620         return;
621     }
622 
623     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
624     if (!stream_endpoint) {
625         log_error("avdtp_media_connect: no stream_endpoint with seid %d found", int_seid);
626         return;
627     }
628 
629     if (stream_endpoint->state < AVDTP_STREAM_ENDPOINT_CONFIGURED) return;
630     if (stream_endpoint->remote_sep_index == AVDTP_INVALID_SEP_INDEX) return;
631 
632     connection->initiator_transaction_label++;
633     connection->acp_seid = acp_seid;
634     connection->int_seid = stream_endpoint->sep.seid;
635     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_OPEN_STREAM;
636     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W2_REQUEST_OPEN_STREAM;
637     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
638 }
639 
640 void avdtp_start_stream(uint8_t int_seid, avdtp_context_t * context){
641     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
642     if (!stream_endpoint) {
643         log_error("avdtp_start_stream: no stream_endpoint with seid %d found", int_seid);
644         return;
645     }
646     avdtp_connection_t * connection = stream_endpoint->connection;
647     if (!connection){
648         log_error("avdtp_start_stream: no connection for seid %d found",stream_endpoint->sep.seid);
649         return;
650     }
651 
652     if (stream_endpoint->remote_sep_index == AVDTP_INVALID_SEP_INDEX || stream_endpoint->start_stream) return;
653     stream_endpoint->start_stream = 1;
654     connection->int_seid = int_seid;
655     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
656 }
657 
658 void avdtp_stop_stream(uint8_t int_seid, avdtp_context_t * context){
659     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
660     if (!stream_endpoint) {
661         log_error("avdtp_stop_stream: no stream_endpoint with seid %d found", int_seid);
662         return;
663     }
664     avdtp_connection_t * connection = stream_endpoint->connection;
665     if (!connection){
666         log_error("avdtp_stop_stream: no connection for seid %d found",stream_endpoint->sep.seid);
667         return;
668     }
669     if (stream_endpoint->remote_sep_index == 0xFF || stream_endpoint->stop_stream) return;
670     stream_endpoint->stop_stream = 1;
671     connection->int_seid = int_seid;
672     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
673 }
674 
675 void avdtp_abort_stream(uint8_t int_seid, avdtp_context_t * context){
676     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
677     if (!stream_endpoint) {
678         log_error("avdtp_abort_stream: no stream_endpoint with seid %d found", int_seid);
679         return;
680     }
681     avdtp_connection_t * connection = stream_endpoint->connection;
682 
683     if (!connection){
684         log_error("avdtp_abort_stream: no connection for seid %d found",stream_endpoint->sep.seid);
685         return;
686     }
687     if (stream_endpoint->remote_sep_index == 0xFF || stream_endpoint->abort_stream) return;
688     stream_endpoint->abort_stream = 1;
689     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
690 }
691 
692 void avdtp_suspend_stream(uint8_t int_seid, avdtp_context_t * context){
693     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
694     if (!stream_endpoint) {
695         log_error("avdtp_abort_stream: no stream_endpoint with seid %d found", int_seid);
696         return;
697     }
698     avdtp_connection_t * connection = stream_endpoint->connection;
699     if (!connection){
700         log_error("avdtp_abort_stream: no connection for seid %d found",stream_endpoint->sep.seid);
701         return;
702     }
703     if (stream_endpoint->remote_sep_index == 0xFF || stream_endpoint->suspend_stream) return;
704     stream_endpoint->suspend_stream = 1;
705     connection->int_seid = int_seid;
706     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
707 }
708 
709 void avdtp_discover_stream_endpoints(uint16_t avdtp_cid, avdtp_context_t * context){
710     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
711     if (!connection){
712         log_error("avdtp_discover_stream_endpoints: no connection for signaling cid 0x%02x found", avdtp_cid);
713         return;
714     }
715     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
716 
717     switch (connection->initiator_connection_state){
718         case AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE:
719             connection->initiator_transaction_label++;
720             connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_DISCOVER_SEPS;
721             avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
722             break;
723         default:
724             log_error("avdtp_discover_stream_endpoints: wrong state");
725             break;
726     }
727 }
728 
729 
730 void avdtp_get_capabilities(uint16_t avdtp_cid, uint8_t acp_seid, avdtp_context_t * context){
731     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
732     if (!connection){
733         log_error("avdtp_get_capabilities: no connection for signaling cid 0x%02x found", avdtp_cid);
734         return;
735     }
736     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
737     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
738     connection->initiator_transaction_label++;
739     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CAPABILITIES;
740     connection->acp_seid = acp_seid;
741     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
742 }
743 
744 
745 void avdtp_get_all_capabilities(uint16_t avdtp_cid, uint8_t acp_seid, avdtp_context_t * context){
746     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
747     if (!connection){
748         log_error("avdtp_get_all_capabilities: no connection for signaling cid 0x%02x found", avdtp_cid);
749         return;
750     }
751     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
752     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
753     connection->initiator_transaction_label++;
754     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_ALL_CAPABILITIES;
755     connection->acp_seid = acp_seid;
756     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
757 }
758 
759 void avdtp_get_configuration(uint16_t avdtp_cid, uint8_t acp_seid, avdtp_context_t * context){
760     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
761     if (!connection){
762         log_error("avdtp_get_configuration: no connection for signaling cid 0x%02x found", avdtp_cid);
763         return;
764     }
765     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
766     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
767     connection->initiator_transaction_label++;
768     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CONFIGURATION;
769     connection->acp_seid = acp_seid;
770     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
771 }
772 
773 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){
774     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
775     if (!connection){
776         log_error("avdtp_set_configuration: no connection for signaling cid 0x%02x found", avdtp_cid);
777         return;
778     }
779     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
780     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
781 
782     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_for_seid(int_seid, context);
783     if (!stream_endpoint) {
784         log_error("avdtp_set_configuration: no initiator stream endpoint for seid %d", int_seid);
785         return;
786     }
787 
788     connection->initiator_transaction_label++;
789     connection->acp_seid = acp_seid;
790     connection->int_seid = int_seid;
791     stream_endpoint->remote_capabilities_bitmap = configured_services_bitmap;
792     stream_endpoint->remote_capabilities = configuration;
793     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_SET_CONFIGURATION;
794     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
795 }
796 
797 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){
798     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
799     if (!connection){
800         log_error("avdtp_reconfigure: no connection for signaling cid 0x%02x found", avdtp_cid);
801         return;
802     }
803     //TODO: if opened only app capabilities, enable reconfigure for not opened
804     if (connection->state < AVDTP_SIGNALING_CONNECTION_OPENED) return;
805     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
806 
807     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_for_seid(int_seid, context);
808     if (!stream_endpoint) {
809         log_error("avdtp_reconfigure: no initiator stream endpoint for seid %d", int_seid);
810         return;
811     }
812 
813     if (stream_endpoint->remote_sep_index == 0xFF){
814         log_error("avdtp_reconfigure: no associated remote sep");
815         return;
816     }
817 
818     connection->initiator_transaction_label++;
819     connection->acp_seid = acp_seid;
820     connection->int_seid = stream_endpoint->sep.seid;
821     stream_endpoint->remote_capabilities_bitmap = configured_services_bitmap;
822     stream_endpoint->remote_capabilities = configuration;
823     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_RECONFIGURE_STREAM_WITH_SEID;
824     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
825 }
826 
827 uint8_t avdtp_remote_seps_num(uint16_t avdtp_cid, avdtp_context_t * context){
828     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
829     if (!connection){
830         log_error("avdtp_suspend: no connection for signaling cid 0x%02x found", avdtp_cid);
831         return 0;
832     }
833     return connection->remote_seps_num;
834 }
835 
836 avdtp_sep_t * avdtp_remote_sep(uint16_t avdtp_cid, uint8_t index, avdtp_context_t * context){
837     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
838     if (!connection){
839         log_error("avdtp_suspend: no connection for signaling cid 0x%02x found", avdtp_cid);
840         return NULL;
841     }
842     return &connection->remote_seps[index];
843 }
844 
845 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){
846     UNUSED(packet_size);
847     if (storage_size < 4) {
848         log_error("storage must have 4 bytes");
849         return;
850     }
851     uint8_t sampling_frequency = avdtp_choose_sbc_sampling_frequency(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_sampling_frequency_bitmap(packet));
852     uint8_t channel_mode = avdtp_choose_sbc_channel_mode(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_channel_mode_bitmap(packet));
853     uint8_t block_length = avdtp_choose_sbc_block_length(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_block_length_bitmap(packet));
854     uint8_t subbands = avdtp_choose_sbc_subbands(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_subbands_bitmap(packet));
855 
856     uint8_t allocation_method = avdtp_choose_sbc_allocation_method(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_allocation_method_bitmap(packet));
857     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));
858     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));
859 
860     config_storage[0] = (sampling_frequency << 4) | channel_mode;
861     config_storage[1] = (block_length << 4) | (subbands << 2) | allocation_method;
862     config_storage[2] = min_bitpool_value;
863     config_storage[3] = max_bitpool_value;
864 
865     stream_endpoint->remote_configuration_bitmap = store_bit16(stream_endpoint->remote_configuration_bitmap, AVDTP_MEDIA_CODEC, 1);
866     stream_endpoint->remote_configuration.media_codec.media_type = AVDTP_AUDIO;
867     stream_endpoint->remote_configuration.media_codec.media_codec_type = AVDTP_CODEC_SBC;
868     stream_endpoint->remote_configuration.media_codec.media_codec_information_len = storage_size;
869     stream_endpoint->remote_configuration.media_codec.media_codec_information = config_storage;
870 }
871 
872 uint8_t avdtp_choose_sbc_channel_mode(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_channel_mode_bitmap){
873     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
874     uint8_t channel_mode_bitmap = (media_codec[0] & 0x0F) & remote_channel_mode_bitmap;
875 
876     uint8_t channel_mode = AVDTP_SBC_STEREO;
877     if (channel_mode_bitmap & AVDTP_SBC_JOINT_STEREO){
878         channel_mode = AVDTP_SBC_JOINT_STEREO;
879     } else if (channel_mode_bitmap & AVDTP_SBC_STEREO){
880         channel_mode = AVDTP_SBC_STEREO;
881     } else if (channel_mode_bitmap & AVDTP_SBC_DUAL_CHANNEL){
882         channel_mode = AVDTP_SBC_DUAL_CHANNEL;
883     } else if (channel_mode_bitmap & AVDTP_SBC_MONO){
884         channel_mode = AVDTP_SBC_MONO;
885     }
886     return channel_mode;
887 }
888 
889 uint8_t avdtp_choose_sbc_allocation_method(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_allocation_method_bitmap){
890     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
891     uint8_t allocation_method_bitmap = (media_codec[1] & 0x03) & remote_allocation_method_bitmap;
892 
893     uint8_t allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
894     if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS){
895         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
896     } else if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_SNR){
897         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_SNR;
898     }
899     return allocation_method;
900 }
901 
902 uint8_t avdtp_stream_endpoint_seid(avdtp_stream_endpoint_t * stream_endpoint){
903     if (!stream_endpoint) return 0;
904     return stream_endpoint->sep.seid;
905 }
906 uint8_t avdtp_choose_sbc_subbands(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_subbands_bitmap){
907     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
908     uint8_t subbands_bitmap = ((media_codec[1] >> 2) & 0x03) & remote_subbands_bitmap;
909 
910     uint8_t subbands = AVDTP_SBC_SUBBANDS_8;
911     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_8){
912         subbands = AVDTP_SBC_SUBBANDS_8;
913     } else if (subbands_bitmap & AVDTP_SBC_SUBBANDS_4){
914         subbands = AVDTP_SBC_SUBBANDS_4;
915     }
916     return subbands;
917 }
918 
919 uint8_t avdtp_choose_sbc_block_length(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_block_length_bitmap){
920     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
921     uint8_t block_length_bitmap = (media_codec[1] >> 4) & remote_block_length_bitmap;
922 
923     uint8_t block_length = AVDTP_SBC_BLOCK_LENGTH_16;
924     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_16){
925         block_length = AVDTP_SBC_BLOCK_LENGTH_16;
926     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_12){
927         block_length = AVDTP_SBC_BLOCK_LENGTH_12;
928     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_8){
929         block_length = AVDTP_SBC_BLOCK_LENGTH_8;
930     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_4){
931         block_length = AVDTP_SBC_BLOCK_LENGTH_4;
932     }
933     return block_length;
934 }
935 
936 uint8_t avdtp_choose_sbc_sampling_frequency(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_sampling_frequency_bitmap){
937     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
938     uint8_t sampling_frequency_bitmap = (media_codec[0] >> 4) & remote_sampling_frequency_bitmap;
939 
940     uint8_t sampling_frequency = AVDTP_SBC_44100;
941     if (sampling_frequency_bitmap & AVDTP_SBC_48000){
942         sampling_frequency = AVDTP_SBC_48000;
943     } else if (sampling_frequency_bitmap & AVDTP_SBC_44100){
944         sampling_frequency = AVDTP_SBC_44100;
945     } else if (sampling_frequency_bitmap & AVDTP_SBC_32000){
946         sampling_frequency = AVDTP_SBC_32000;
947     } else if (sampling_frequency_bitmap & AVDTP_SBC_16000){
948         sampling_frequency = AVDTP_SBC_16000;
949     }
950     return sampling_frequency;
951 }
952 
953 uint8_t avdtp_choose_sbc_max_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_max_bitpool_value){
954     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
955     return btstack_min(media_codec[3], remote_max_bitpool_value);
956 }
957 
958 uint8_t avdtp_choose_sbc_min_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_min_bitpool_value){
959     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
960     return btstack_max(media_codec[2], remote_min_bitpool_value);
961 }