xref: /btstack/src/classic/avdtp.c (revision 3e3fbf3df68dce1ab27af5efcdf0ea980eb93f6c)
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 #include <unistd.h>
46 
47 #include "btstack.h"
48 #include "avdtp.h"
49 #include "avdtp_util.h"
50 #include "avdtp_acceptor.h"
51 #include "avdtp_initiator.h"
52 
53 static int record_id = -1;
54 static uint8_t   attribute_value[1000];
55 static const unsigned int attribute_value_buffer_size = sizeof(attribute_value);
56 
57 typedef struct {
58     avdtp_connection_t * connection;
59     btstack_packet_handler_t avdtp_callback;
60     avdtp_sep_type_t query_role;
61     btstack_packet_handler_t packet_handler;
62 } avdtp_sdp_query_context_t;
63 
64 static avdtp_sdp_query_context_t sdp_query_context;
65 
66 static void (*handle_media_data)(avdtp_stream_endpoint_t * stream_endpoint, uint8_t *packet, uint16_t size);
67 static void avdtp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
68 
69 void avdtp_connect(bd_addr_t remote, avdtp_sep_type_t query_role, avdtp_context_t * avdtp_context){
70     sdp_query_context.connection = NULL;
71     avdtp_connection_t * connection = avdtp_connection_for_bd_addr(remote, avdtp_context);
72     if (!connection){
73         connection = avdtp_create_connection(remote, avdtp_context);
74     }
75     if (connection->state != AVDTP_SIGNALING_CONNECTION_IDLE) return;
76     connection->state = AVDTP_SIGNALING_W4_SDP_QUERY_COMPLETE;
77     sdp_query_context.connection = connection;
78     sdp_query_context.query_role = query_role;
79     sdp_query_context.avdtp_callback = avdtp_context->avdtp_callback;
80     sdp_query_context.packet_handler = avdtp_context->packet_handler;
81 
82     sdp_client_query_uuid16(&avdtp_handle_sdp_client_query_result, remote, BLUETOOTH_PROTOCOL_AVDTP);
83 }
84 
85 void avdtp_register_media_transport_category(avdtp_stream_endpoint_t * stream_endpoint){
86     if (!stream_endpoint){
87         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
88         return;
89     }
90     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_TRANSPORT, 1);
91     stream_endpoint->sep.registered_service_categories = bitmap;
92 }
93 
94 void avdtp_register_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
95     if (!stream_endpoint){
96         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
97         return;
98     }
99     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_REPORTING, 1);
100     stream_endpoint->sep.registered_service_categories = bitmap;
101 }
102 
103 void avdtp_register_delay_reporting_category(avdtp_stream_endpoint_t * stream_endpoint){
104     if (!stream_endpoint){
105         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
106         return;
107     }
108     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_DELAY_REPORTING, 1);
109     stream_endpoint->sep.registered_service_categories = bitmap;
110 }
111 
112 void avdtp_register_recovery_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t maximum_recovery_window_size, uint8_t maximum_number_media_packets){
113     if (!stream_endpoint){
114         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
115         return;
116     }
117     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_RECOVERY, 1);
118     stream_endpoint->sep.registered_service_categories = bitmap;
119     stream_endpoint->sep.capabilities.recovery.recovery_type = 0x01; // 0x01 = RFC2733
120     stream_endpoint->sep.capabilities.recovery.maximum_recovery_window_size = maximum_recovery_window_size;
121     stream_endpoint->sep.capabilities.recovery.maximum_number_media_packets = maximum_number_media_packets;
122 }
123 
124 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){
125     if (!stream_endpoint){
126         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
127         return;
128     }
129     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_CONTENT_PROTECTION, 1);
130     stream_endpoint->sep.registered_service_categories = bitmap;
131     stream_endpoint->sep.capabilities.content_protection.cp_type = cp_type;
132     stream_endpoint->sep.capabilities.content_protection.cp_type_value = cp_type_value;
133     stream_endpoint->sep.capabilities.content_protection.cp_type_value_len = cp_type_value_len;
134 }
135 
136 void avdtp_register_header_compression_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t back_ch, uint8_t media, uint8_t recovery){
137     if (!stream_endpoint){
138         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
139         return;
140     }
141     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_HEADER_COMPRESSION, 1);
142     stream_endpoint->sep.registered_service_categories = bitmap;
143     stream_endpoint->sep.capabilities.header_compression.back_ch = back_ch;
144     stream_endpoint->sep.capabilities.header_compression.media = media;
145     stream_endpoint->sep.capabilities.header_compression.recovery = recovery;
146 }
147 
148 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){
149     if (!stream_endpoint){
150         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
151         return;
152     }
153     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MEDIA_CODEC, 1);
154     stream_endpoint->sep.registered_service_categories = bitmap;
155     stream_endpoint->sep.capabilities.media_codec.media_type = media_type;
156     stream_endpoint->sep.capabilities.media_codec.media_codec_type = media_codec_type;
157     stream_endpoint->sep.capabilities.media_codec.media_codec_information = media_codec_info;
158     stream_endpoint->sep.capabilities.media_codec.media_codec_information_len = media_codec_info_len;
159 }
160 
161 void avdtp_register_multiplexing_category(avdtp_stream_endpoint_t * stream_endpoint, uint8_t fragmentation){
162     if (!stream_endpoint){
163         log_error("avdtp_register_media_transport_category: stream endpoint with given seid is not registered");
164         return;
165     }
166     uint16_t bitmap = store_bit16(stream_endpoint->sep.registered_service_categories, AVDTP_MULTIPLEXING, 1);
167     stream_endpoint->sep.registered_service_categories = bitmap;
168     stream_endpoint->sep.capabilities.multiplexing_mode.fragmentation = fragmentation;
169 }
170 
171 
172 /* START: tracking can send now requests pro l2cap cid */
173 void avdtp_handle_can_send_now(avdtp_connection_t * connection, uint16_t l2cap_cid, avdtp_context_t * context){
174     if (connection->wait_to_send_acceptor){
175         connection->wait_to_send_acceptor = 0;
176         avdtp_acceptor_stream_config_subsm_run(connection, context);
177     } else if (connection->wait_to_send_initiator){
178         connection->wait_to_send_initiator = 0;
179         avdtp_initiator_stream_config_subsm_run(connection, context);
180     } else if (connection->wait_to_send_self){
181         connection->wait_to_send_self = 0;
182         if (connection->disconnect){
183             btstack_linked_list_iterator_t it;
184             btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
185             while (btstack_linked_list_iterator_has_next(&it)){
186                 avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
187                 if (stream_endpoint->connection == connection){
188                     if (stream_endpoint->state >= AVDTP_STREAM_ENDPOINT_OPENED && stream_endpoint->state != AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_DISCONNECTED){
189                         stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_DISCONNECTED;
190                         avdtp_request_can_send_now_self(connection, connection->l2cap_signaling_cid);
191                         l2cap_disconnect(stream_endpoint->l2cap_media_cid, 0);
192                         return;
193                     }
194                 }
195             }
196             connection->disconnect = 0;
197             connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED;
198             l2cap_disconnect(connection->l2cap_signaling_cid, 0);
199             return;
200         }
201     }
202 
203     // re-register
204     int more_to_send = connection->wait_to_send_acceptor || connection->wait_to_send_initiator || connection->wait_to_send_self;
205     if (more_to_send){
206         l2cap_request_can_send_now_event(l2cap_cid);
207     }
208 }
209 /* END: tracking can send now requests pro l2cap cid */
210 
211 avdtp_connection_t * avdtp_create_connection(bd_addr_t remote_addr, avdtp_context_t * context){
212     avdtp_connection_t * connection = btstack_memory_avdtp_connection_get();
213     memset(connection, 0, sizeof(avdtp_connection_t));
214     connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
215     connection->initiator_transaction_label++;
216     memcpy(connection->remote_addr, remote_addr, 6);
217     btstack_linked_list_add(&context->connections, (btstack_linked_item_t *) connection);
218     return connection;
219 }
220 
221 avdtp_stream_endpoint_t * avdtp_create_stream_endpoint(avdtp_sep_type_t sep_type, avdtp_media_type_t media_type, avdtp_context_t * context){
222     avdtp_stream_endpoint_t * stream_endpoint = btstack_memory_avdtp_stream_endpoint_get();
223     memset(stream_endpoint, 0, sizeof(avdtp_stream_endpoint_t));
224     context->stream_endpoints_id_counter++;
225     stream_endpoint->sep.seid = context->stream_endpoints_id_counter;
226     stream_endpoint->sep.media_type = media_type;
227     stream_endpoint->sep.type = sep_type;
228     btstack_linked_list_add(&context->stream_endpoints, (btstack_linked_item_t *) stream_endpoint);
229     return stream_endpoint;
230 }
231 
232 
233 static void handle_l2cap_data_packet_for_signaling_connection(avdtp_connection_t * connection, uint8_t *packet, uint16_t size, avdtp_context_t * context){
234     int offset = avdtp_read_signaling_header(&connection->signaling_packet, packet, size);
235     switch (connection->signaling_packet.message_type){
236         case AVDTP_CMD_MSG:
237             avdtp_acceptor_stream_config_subsm(connection, packet, size, offset, context);
238             break;
239         default:
240             avdtp_initiator_stream_config_subsm(connection, packet, size, offset, context);
241             break;
242     }
243 }
244 
245 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){
246     uint16_t local_cid;
247     switch (packet_type){
248         case L2CAP_DATA_PACKET:{
249             int offset = avdtp_read_signaling_header(&connection->signaling_packet, packet, size);
250             if (connection->signaling_packet.message_type == AVDTP_CMD_MSG){
251                 avdtp_acceptor_stream_config_subsm(connection, packet, size, offset, context);
252             } else {
253                 avdtp_initiator_stream_config_subsm(connection, packet, size, offset, context);
254             }
255             break;
256         }
257         case HCI_EVENT_PACKET:
258             switch (event){
259                 case L2CAP_EVENT_CHANNEL_OPENED:
260                     if (stream_endpoint->l2cap_media_cid == 0){
261                         if (stream_endpoint->state != AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_CONNECTED) return;
262                         stream_endpoint->state = AVDTP_STREAM_ENDPOINT_OPENED;
263                         stream_endpoint->connection = connection;
264                         stream_endpoint->l2cap_media_cid = l2cap_event_channel_opened_get_local_cid(packet);
265                         stream_endpoint->media_con_handle = l2cap_event_channel_opened_get_handle(packet);
266                         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);
267                         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);
268                         break;
269                     }
270                     break;
271                 case L2CAP_EVENT_CHANNEL_CLOSED:
272                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
273                     if (stream_endpoint->l2cap_media_cid == local_cid){
274                         stream_endpoint->l2cap_media_cid = 0;
275                         log_info(" -> L2CAP_EVENT_CHANNEL_CLOSED: AVDTP_STREAM_ENDPOINT_IDLE");
276                         stream_endpoint->state = AVDTP_STREAM_ENDPOINT_IDLE;
277                         stream_endpoint->acceptor_config_state = AVDTP_ACCEPTOR_STREAM_CONFIG_IDLE;
278                         stream_endpoint->initiator_config_state = AVDTP_INITIATOR_STREAM_CONFIG_IDLE;
279                         stream_endpoint->remote_sep_index = 0;
280                         break;
281                     }
282                     if (stream_endpoint->l2cap_recovery_cid == local_cid){
283                         log_info(" -> L2CAP_EVENT_CHANNEL_CLOSED recovery cid 0x%0x", local_cid);
284                         stream_endpoint->l2cap_recovery_cid = 0;
285                         break;
286                     }
287 
288                     if (stream_endpoint->l2cap_reporting_cid == local_cid){
289                         log_info("L2CAP_EVENT_CHANNEL_CLOSED reporting cid 0x%0x", local_cid);
290                         stream_endpoint->l2cap_reporting_cid = 0;
291                         break;
292                     }
293                     break;
294                 default:
295                     break;
296             }
297             break;
298         default:
299             break;
300     }
301 }
302 
303 static void avdtp_handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
304     UNUSED(packet_type);
305     UNUSED(channel);
306     UNUSED(size);
307 
308     des_iterator_t des_list_it;
309     des_iterator_t prot_it;
310     uint32_t avdtp_remote_uuid    = 0;
311     uint16_t avdtp_l2cap_psm      = 0;
312     uint16_t avdtp_version        = 0;
313 
314     if (!sdp_query_context.connection) return;
315 
316     switch (hci_event_packet_get_type(packet)){
317         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
318             // Handle new SDP record
319             if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id) {
320                 record_id = sdp_event_query_attribute_byte_get_record_id(packet);
321                 // log_info("SDP Record: Nr: %d", record_id);
322             }
323 
324             if (sdp_event_query_attribute_byte_get_attribute_length(packet) <= attribute_value_buffer_size) {
325                 attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
326 
327                 if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)) {
328 
329                     switch(sdp_event_query_attribute_byte_get_attribute_id(packet)) {
330                         case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
331                             if (de_get_element_type(attribute_value) != DE_DES) break;
332                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
333                                 uint8_t * element = des_iterator_get_element(&des_list_it);
334                                 if (de_get_element_type(element) != DE_UUID) continue;
335                                 uint32_t uuid = de_get_uuid32(element);
336                                 switch (uuid){
337                                     case BLUETOOTH_SERVICE_CLASS_AUDIO_SOURCE:
338                                         if (sdp_query_context.query_role != AVDTP_SOURCE) {
339                                             sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
340                                             avdtp_signaling_emit_connection_established(sdp_query_context.avdtp_callback, sdp_query_context.connection->l2cap_signaling_cid, sdp_query_context.connection->remote_addr, 0);
341                                             break;
342                                         }
343                                         // log_info("SDP Attribute 0x%04x: AVDTP SOURCE protocol UUID: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
344                                         avdtp_remote_uuid = uuid;
345                                         break;
346                                     case BLUETOOTH_SERVICE_CLASS_AUDIO_SINK:
347                                         if (sdp_query_context.query_role != AVDTP_SINK) {
348                                             sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
349                                             avdtp_signaling_emit_connection_established(sdp_query_context.avdtp_callback, sdp_query_context.connection->l2cap_signaling_cid, sdp_query_context.connection->remote_addr, 0);
350                                             break;
351                                         }
352                                         // log_info("SDP Attribute 0x%04x: AVDTP SINK protocol UUID: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
353                                         avdtp_remote_uuid = uuid;
354                                         break;
355                                     default:
356                                         break;
357                                 }
358                             }
359                             break;
360 
361                         case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST: {
362                                 // log_info("SDP Attribute: 0x%04x", sdp_event_query_attribute_byte_get_attribute_id(packet));
363 
364                                 for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)) {
365                                     uint8_t       *des_element;
366                                     uint8_t       *element;
367                                     uint32_t       uuid;
368 
369                                     if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
370 
371                                     des_element = des_iterator_get_element(&des_list_it);
372                                     des_iterator_init(&prot_it, des_element);
373                                     element = des_iterator_get_element(&prot_it);
374 
375                                     if (de_get_element_type(element) != DE_UUID) continue;
376 
377                                     uuid = de_get_uuid32(element);
378                                     switch (uuid){
379                                         case BLUETOOTH_PROTOCOL_L2CAP:
380                                             if (!des_iterator_has_more(&prot_it)) continue;
381                                             des_iterator_next(&prot_it);
382                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &avdtp_l2cap_psm);
383                                             break;
384                                         case BLUETOOTH_PROTOCOL_AVDTP:
385                                             if (!des_iterator_has_more(&prot_it)) continue;
386                                             des_iterator_next(&prot_it);
387                                             de_element_get_uint16(des_iterator_get_element(&prot_it), &avdtp_version);
388                                             break;
389                                         default:
390                                             break;
391                                     }
392                                 }
393                                 if (!avdtp_l2cap_psm) {
394                                     sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_IDLE;
395                                     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);
396                                     break;
397                                 }
398                                 sdp_query_context.connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
399                                 l2cap_create_channel(sdp_query_context.packet_handler, sdp_query_context.connection->remote_addr, avdtp_l2cap_psm, l2cap_max_mtu(), NULL);
400                             }
401                             break;
402                         default:
403                             break;
404                     }
405                 }
406             } else {
407                 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));
408             }
409             break;
410 
411         case SDP_EVENT_QUERY_COMPLETE:
412             log_info("General query done with status %d.", sdp_event_query_complete_get_status(packet));
413             break;
414     }
415 }
416 
417 
418 void avdtp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size, avdtp_context_t * context){
419     bd_addr_t event_addr;
420     hci_con_handle_t con_handle;
421     uint16_t psm;
422     uint16_t local_cid;
423     avdtp_stream_endpoint_t * stream_endpoint = NULL;
424     avdtp_connection_t * connection = NULL;
425     btstack_linked_list_t * avdtp_connections = &context->connections;
426     btstack_linked_list_t * stream_endpoints =  &context->stream_endpoints;
427     handle_media_data = context->handle_media_data;
428     // log_info("avdtp_packet_handler packet type %02x, event %02x ", packet_type, hci_event_packet_get_type(packet));
429     switch (packet_type) {
430         case L2CAP_DATA_PACKET:
431             connection = avdtp_connection_for_l2cap_signaling_cid(channel, context);
432             if (connection){
433                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size, context);
434                 break;
435             }
436 
437             stream_endpoint = avdtp_stream_endpoint_for_l2cap_cid(channel, context);
438             if (!stream_endpoint){
439                 if (!connection) break;
440                 handle_l2cap_data_packet_for_signaling_connection(connection, packet, size, context);
441                 break;
442             }
443 
444             if (channel == stream_endpoint->connection->l2cap_signaling_cid){
445                 stream_endpoint_state_machine(stream_endpoint->connection, stream_endpoint, L2CAP_DATA_PACKET, 0, packet, size, context);
446                 break;
447             }
448 
449             if (channel == stream_endpoint->l2cap_media_cid){
450                 (*handle_media_data)(stream_endpoint, packet, size);
451                 break;
452             }
453 
454             if (channel == stream_endpoint->l2cap_reporting_cid){
455                 // TODO
456                 log_info("L2CAP_DATA_PACKET for reporting: NOT IMPLEMENTED");
457             } else if (channel == stream_endpoint->l2cap_recovery_cid){
458                 // TODO
459                 log_info("L2CAP_DATA_PACKET for recovery: NOT IMPLEMENTED");
460             } else {
461                 log_error("avdtp packet handler L2CAP_DATA_PACKET: local cid 0x%02x not found", channel);
462             }
463             break;
464 
465         case HCI_EVENT_PACKET:
466             switch (hci_event_packet_get_type(packet)) {
467                 case L2CAP_EVENT_INCOMING_CONNECTION:
468                     l2cap_event_incoming_connection_get_address(packet, event_addr);
469                     local_cid = l2cap_event_incoming_connection_get_local_cid(packet);
470 
471                     connection = avdtp_connection_for_bd_addr(event_addr, context);
472 
473                     if (!connection || connection->state == AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED){
474                         connection = avdtp_create_connection(event_addr, context);
475                         connection->state = AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED;
476                         log_info("L2CAP_EVENT_INCOMING_CONNECTION, connection %p, state connection %d", connection, connection->state);
477                         l2cap_accept_connection(local_cid);
478                         break;
479                     }
480 
481                     stream_endpoint = avdtp_stream_endpoint_for_seid(connection->query_seid, context);
482                     if (!stream_endpoint) {
483                         log_info("L2CAP_EVENT_INCOMING_CONNECTION no streamendpoint found for seid %d", connection->query_seid);
484                         break;
485                     }
486 
487                     if (stream_endpoint->l2cap_media_cid == 0){
488                         if (stream_endpoint->state != AVDTP_STREAM_ENDPOINT_W4_L2CAP_FOR_MEDIA_CONNECTED) break;
489                         l2cap_accept_connection(local_cid);
490                         break;
491                     }
492                     break;
493 
494                 case L2CAP_EVENT_CHANNEL_OPENED:
495                     // inform about new l2cap connection
496                     l2cap_event_channel_opened_get_address(packet, event_addr);
497                     if (l2cap_event_channel_opened_get_status(packet)){
498                         log_error("L2CAP connection to connection %s failed. status code 0x%02x",
499                             bd_addr_to_str(event_addr), l2cap_event_channel_opened_get_status(packet));
500                         break;
501                     }
502                     psm = l2cap_event_channel_opened_get_psm(packet);
503                     if (psm != BLUETOOTH_PROTOCOL_AVDTP){
504                         log_error("unexpected PSM - Not implemented yet, avdtp sink: L2CAP_EVENT_CHANNEL_OPENED");
505                         return;
506                     }
507 
508                     con_handle = l2cap_event_channel_opened_get_handle(packet);
509                     local_cid = l2cap_event_channel_opened_get_local_cid(packet);
510 
511                     log_info("L2CAP_EVENT_CHANNEL_OPENED: Channel successfully opened: %s, handle 0x%02x, psm 0x%02x, local cid 0x%02x, remote cid 0x%02x",
512                            bd_addr_to_str(event_addr), con_handle, psm, local_cid,  l2cap_event_channel_opened_get_remote_cid(packet));
513 
514                     if (psm != BLUETOOTH_PROTOCOL_AVDTP) break;
515 
516                     connection = avdtp_connection_for_bd_addr(event_addr, context);
517                     if (!connection) break;
518 
519                     if (connection->l2cap_signaling_cid == 0) {
520                         if (connection->state != AVDTP_SIGNALING_CONNECTION_W4_L2CAP_CONNECTED) break;
521                         connection->l2cap_signaling_cid = local_cid;
522                         connection->con_handle = con_handle;
523                         connection->query_seid = 0;
524                         connection->state = AVDTP_SIGNALING_CONNECTION_OPENED;
525                         log_info(" -> AVDTP_SIGNALING_CONNECTION_OPENED, connection %p", connection);
526                         avdtp_signaling_emit_connection_established(context->avdtp_callback, connection->l2cap_signaling_cid, event_addr, 0);
527                         break;
528                     }
529 
530                     stream_endpoint = avdtp_stream_endpoint_for_seid(connection->query_seid, context);
531                     if (!stream_endpoint){
532                         log_info("L2CAP_EVENT_CHANNEL_OPENED: stream_endpoint not found");
533                         return;
534                     }
535                     stream_endpoint_state_machine(connection, stream_endpoint, HCI_EVENT_PACKET, L2CAP_EVENT_CHANNEL_OPENED, packet, size, context);
536                     break;
537 
538                 case L2CAP_EVENT_CHANNEL_CLOSED:
539                     // data: event (8), len(8), channel (16)
540                     local_cid = l2cap_event_channel_closed_get_local_cid(packet);
541                     connection = avdtp_connection_for_l2cap_signaling_cid(local_cid, context);
542                     log_info(" -> L2CAP_EVENT_CHANNEL_CLOSED signaling cid 0x%0x", local_cid);
543 
544                     if (connection){
545                         log_info(" -> AVDTP_STREAM_ENDPOINT_IDLE, connection closed");
546                         btstack_linked_list_remove(avdtp_connections, (btstack_linked_item_t*) connection);
547                         btstack_linked_list_iterator_t it;
548                         btstack_linked_list_iterator_init(&it, stream_endpoints);
549                         while (btstack_linked_list_iterator_has_next(&it)){
550                             avdtp_stream_endpoint_t * _stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
551                             avdtp_initialize_stream_endpoint(_stream_endpoint);
552                         }
553                         break;
554                     }
555 
556                     stream_endpoint = avdtp_stream_endpoint_for_l2cap_cid(local_cid, context);
557                     if (!stream_endpoint) return;
558 
559                     stream_endpoint_state_machine(connection, stream_endpoint, HCI_EVENT_PACKET, L2CAP_EVENT_CHANNEL_CLOSED, packet, size, context);
560                     break;
561 
562                 case HCI_EVENT_DISCONNECTION_COMPLETE:
563                     break;
564 
565                 case L2CAP_EVENT_CAN_SEND_NOW:
566                     connection = avdtp_connection_for_l2cap_signaling_cid(channel, context);
567                     if (!connection) {
568                         stream_endpoint = avdtp_stream_endpoint_for_l2cap_cid(channel, context);
569                         if (!stream_endpoint->connection) break;
570                         connection = stream_endpoint->connection;
571                     }
572                     avdtp_handle_can_send_now(connection, channel, context);
573                     break;
574                 default:
575                     log_info("unknown HCI event type %02x", hci_event_packet_get_type(packet));
576                     break;
577             }
578             break;
579 
580         default:
581             // other packet type
582             break;
583     }
584 }
585 
586 void avdtp_disconnect(uint16_t avdtp_cid, avdtp_context_t * context){
587     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
588     if (!connection) return;
589     if (connection->state == AVDTP_SIGNALING_CONNECTION_IDLE) return;
590     if (connection->state == AVDTP_SIGNALING_CONNECTION_W4_L2CAP_DISCONNECTED) return;
591 
592     connection->disconnect = 1;
593     avdtp_request_can_send_now_self(connection, connection->l2cap_signaling_cid);
594 }
595 
596 void avdtp_open_stream(uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, avdtp_context_t * context){
597     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
598     if (!connection){
599         log_error("avdtp_media_connect: no connection for signaling cid 0x%02x found", avdtp_cid);
600         return;
601     }
602     if (avdtp_find_remote_sep(connection, acp_seid) == 0xFF){
603         log_error("avdtp_media_connect: no remote sep for seid %d found", acp_seid);
604         return;
605     }
606 
607     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) {
608         log_error("avdtp_media_connect: wrong connection state %d", connection->state);
609         return;
610     }
611 
612     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
613     if (!stream_endpoint) {
614         log_error("avdtp_media_connect: no stream_endpoint with seid %d found", int_seid);
615         return;
616     }
617 
618     if (stream_endpoint->state < AVDTP_STREAM_ENDPOINT_CONFIGURED) return;
619     if (stream_endpoint->remote_sep_index == AVDTP_INVALID_SEP_INDEX) return;
620 
621     connection->initiator_transaction_label++;
622     connection->acp_seid = acp_seid;
623     connection->int_seid = stream_endpoint->sep.seid;
624     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_OPEN_STREAM;
625     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_W2_REQUEST_OPEN_STREAM;
626     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
627 }
628 
629 void avdtp_start_stream(uint8_t int_seid, avdtp_context_t * context){
630     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
631     if (!stream_endpoint) {
632         log_error("avdtp_start_stream: no stream_endpoint with seid %d found", int_seid);
633         return;
634     }
635     avdtp_connection_t * connection = stream_endpoint->connection;
636     if (!connection){
637         log_error("avdtp_start_stream: no connection for seid %d found",stream_endpoint->sep.seid);
638         return;
639     }
640 
641     if (stream_endpoint->remote_sep_index == AVDTP_INVALID_SEP_INDEX || stream_endpoint->start_stream) return;
642     stream_endpoint->start_stream = 1;
643     connection->int_seid = int_seid;
644     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
645 }
646 
647 void avdtp_stop_stream(uint8_t int_seid, avdtp_context_t * context){
648     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
649     if (!stream_endpoint) {
650         log_error("avdtp_stop_stream: no stream_endpoint with seid %d found", int_seid);
651         return;
652     }
653     avdtp_connection_t * connection = stream_endpoint->connection;
654     if (!connection){
655         log_error("avdtp_stop_stream: no connection for seid %d found",stream_endpoint->sep.seid);
656         return;
657     }
658     if (stream_endpoint->remote_sep_index == 0xFF || stream_endpoint->stop_stream) return;
659     stream_endpoint->stop_stream = 1;
660     connection->int_seid = int_seid;
661     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
662 }
663 
664 void avdtp_abort_stream(uint8_t int_seid, avdtp_context_t * context){
665     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
666     if (!stream_endpoint) {
667         log_error("avdtp_abort_stream: no stream_endpoint with seid %d found", int_seid);
668         return;
669     }
670     avdtp_connection_t * connection = stream_endpoint->connection;
671 
672     if (!connection){
673         log_error("avdtp_abort_stream: no connection for seid %d found",stream_endpoint->sep.seid);
674         return;
675     }
676     if (stream_endpoint->remote_sep_index == 0xFF || stream_endpoint->abort_stream) return;
677     stream_endpoint->abort_stream = 1;
678     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
679 }
680 
681 void avdtp_suspend_stream(uint8_t int_seid, avdtp_context_t * context){
682     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_with_seid(int_seid, context);
683     if (!stream_endpoint) {
684         log_error("avdtp_abort_stream: no stream_endpoint with seid %d found", int_seid);
685         return;
686     }
687     avdtp_connection_t * connection = stream_endpoint->connection;
688     if (!connection){
689         log_error("avdtp_abort_stream: no connection for seid %d found",stream_endpoint->sep.seid);
690         return;
691     }
692     if (stream_endpoint->remote_sep_index == 0xFF || stream_endpoint->suspend_stream) return;
693     stream_endpoint->suspend_stream = 1;
694     connection->int_seid = int_seid;
695     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
696 }
697 
698 void avdtp_discover_stream_endpoints(uint16_t avdtp_cid, avdtp_context_t * context){
699     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
700     if (!connection){
701         log_error("avdtp_discover_stream_endpoints: no connection for signaling cid 0x%02x found", avdtp_cid);
702         return;
703     }
704     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
705 
706     switch (connection->initiator_connection_state){
707         case AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE:
708             connection->initiator_transaction_label++;
709             connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_DISCOVER_SEPS;
710             avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
711             break;
712         default:
713             log_error("avdtp_discover_stream_endpoints: wrong state");
714             break;
715     }
716 }
717 
718 
719 void avdtp_get_capabilities(uint16_t avdtp_cid, uint8_t acp_seid, avdtp_context_t * context){
720     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
721     if (!connection){
722         log_error("avdtp_get_capabilities: no connection for signaling cid 0x%02x found", avdtp_cid);
723         return;
724     }
725     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
726     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
727     connection->initiator_transaction_label++;
728     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CAPABILITIES;
729     connection->acp_seid = acp_seid;
730     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
731 }
732 
733 
734 void avdtp_get_all_capabilities(uint16_t avdtp_cid, uint8_t acp_seid, avdtp_context_t * context){
735     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
736     if (!connection){
737         log_error("avdtp_get_all_capabilities: no connection for signaling cid 0x%02x found", avdtp_cid);
738         return;
739     }
740     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
741     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
742     connection->initiator_transaction_label++;
743     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_ALL_CAPABILITIES;
744     connection->acp_seid = acp_seid;
745     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
746 }
747 
748 void avdtp_get_configuration(uint16_t avdtp_cid, uint8_t acp_seid, avdtp_context_t * context){
749     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
750     if (!connection){
751         log_error("avdtp_get_configuration: no connection for signaling cid 0x%02x found", avdtp_cid);
752         return;
753     }
754     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
755     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
756     connection->initiator_transaction_label++;
757     connection->initiator_connection_state = AVDTP_SIGNALING_CONNECTION_INITIATOR_W2_GET_CONFIGURATION;
758     connection->acp_seid = acp_seid;
759     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
760 }
761 
762 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){
763     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
764     if (!connection){
765         log_error("avdtp_set_configuration: no connection for signaling cid 0x%02x found", avdtp_cid);
766         return;
767     }
768     if (connection->state != AVDTP_SIGNALING_CONNECTION_OPENED) return;
769     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
770 
771     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_for_seid(int_seid, context);
772     if (!stream_endpoint) {
773         log_error("avdtp_set_configuration: no initiator stream endpoint for seid %d", int_seid);
774         return;
775     }
776 
777     connection->initiator_transaction_label++;
778     connection->acp_seid = acp_seid;
779     connection->int_seid = int_seid;
780     stream_endpoint->remote_capabilities_bitmap = configured_services_bitmap;
781     stream_endpoint->remote_capabilities = configuration;
782     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_SET_CONFIGURATION;
783     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
784 }
785 
786 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){
787     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
788     if (!connection){
789         log_error("avdtp_reconfigure: no connection for signaling cid 0x%02x found", avdtp_cid);
790         return;
791     }
792     //TODO: if opened only app capabilities, enable reconfigure for not opened
793     if (connection->state < AVDTP_SIGNALING_CONNECTION_OPENED) return;
794     if (connection->initiator_connection_state != AVDTP_SIGNALING_CONNECTION_INITIATOR_IDLE) return;
795 
796     avdtp_stream_endpoint_t * stream_endpoint = avdtp_stream_endpoint_for_seid(int_seid, context);
797     if (!stream_endpoint) {
798         log_error("avdtp_reconfigure: no initiator stream endpoint for seid %d", int_seid);
799         return;
800     }
801 
802     if (stream_endpoint->remote_sep_index == 0xFF){
803         log_error("avdtp_reconfigure: no associated remote sep");
804         return;
805     }
806 
807     connection->initiator_transaction_label++;
808     connection->acp_seid = acp_seid;
809     connection->int_seid = stream_endpoint->sep.seid;
810     stream_endpoint->remote_capabilities_bitmap = configured_services_bitmap;
811     stream_endpoint->remote_capabilities = configuration;
812     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_W2_RECONFIGURE_STREAM_WITH_SEID;
813     avdtp_request_can_send_now_initiator(connection, connection->l2cap_signaling_cid);
814 }
815 
816 uint8_t avdtp_remote_seps_num(uint16_t avdtp_cid, avdtp_context_t * context){
817     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
818     if (!connection){
819         log_error("avdtp_suspend: no connection for signaling cid 0x%02x found", avdtp_cid);
820         return 0;
821     }
822     return connection->remote_seps_num;
823 }
824 
825 avdtp_sep_t * avdtp_remote_sep(uint16_t avdtp_cid, uint8_t index, avdtp_context_t * context){
826     avdtp_connection_t * connection = avdtp_connection_for_l2cap_signaling_cid(avdtp_cid, context);
827     if (!connection){
828         log_error("avdtp_suspend: no connection for signaling cid 0x%02x found", avdtp_cid);
829         return NULL;
830     }
831     return &connection->remote_seps[index];
832 }
833 
834 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){
835     UNUSED(packet_size);
836     if (storage_size < 4) {
837         log_error("storage must have 4 bytes");
838         return;
839     }
840     uint8_t sampling_frequency = avdtp_choose_sbc_sampling_frequency(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_sampling_frequency_bitmap(packet));
841     uint8_t channel_mode = avdtp_choose_sbc_channel_mode(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_channel_mode_bitmap(packet));
842     uint8_t block_length = avdtp_choose_sbc_block_length(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_block_length_bitmap(packet));
843     uint8_t subbands = avdtp_choose_sbc_subbands(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_subbands_bitmap(packet));
844 
845     uint8_t allocation_method = avdtp_choose_sbc_allocation_method(stream_endpoint, avdtp_subevent_signaling_media_codec_sbc_capability_get_allocation_method_bitmap(packet));
846     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));
847     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));
848 
849     config_storage[0] = (sampling_frequency << 4) | channel_mode;
850     config_storage[1] = (block_length << 4) | (subbands << 2) | allocation_method;
851     config_storage[2] = min_bitpool_value;
852     config_storage[3] = max_bitpool_value;
853 
854     stream_endpoint->remote_configuration_bitmap = store_bit16(stream_endpoint->remote_configuration_bitmap, AVDTP_MEDIA_CODEC, 1);
855     stream_endpoint->remote_configuration.media_codec.media_type = AVDTP_AUDIO;
856     stream_endpoint->remote_configuration.media_codec.media_codec_type = AVDTP_CODEC_SBC;
857     stream_endpoint->remote_configuration.media_codec.media_codec_information_len = storage_size;
858     stream_endpoint->remote_configuration.media_codec.media_codec_information = config_storage;
859 }
860 
861 uint8_t avdtp_choose_sbc_channel_mode(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_channel_mode_bitmap){
862     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
863     uint8_t channel_mode_bitmap = (media_codec[0] & 0x0F) & remote_channel_mode_bitmap;
864 
865     uint8_t channel_mode = AVDTP_SBC_STEREO;
866     if (channel_mode_bitmap & AVDTP_SBC_JOINT_STEREO){
867         channel_mode = AVDTP_SBC_JOINT_STEREO;
868     } else if (channel_mode_bitmap & AVDTP_SBC_STEREO){
869         channel_mode = AVDTP_SBC_STEREO;
870     } else if (channel_mode_bitmap & AVDTP_SBC_DUAL_CHANNEL){
871         channel_mode = AVDTP_SBC_DUAL_CHANNEL;
872     } else if (channel_mode_bitmap & AVDTP_SBC_MONO){
873         channel_mode = AVDTP_SBC_MONO;
874     }
875     return channel_mode;
876 }
877 
878 uint8_t avdtp_choose_sbc_allocation_method(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_allocation_method_bitmap){
879     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
880     uint8_t allocation_method_bitmap = (media_codec[1] & 0x03) & remote_allocation_method_bitmap;
881 
882     uint8_t allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
883     if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS){
884         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_LOUDNESS;
885     } else if (allocation_method_bitmap & AVDTP_SBC_ALLOCATION_METHOD_SNR){
886         allocation_method = AVDTP_SBC_ALLOCATION_METHOD_SNR;
887     }
888     return allocation_method;
889 }
890 
891 uint8_t avdtp_stream_endpoint_seid(avdtp_stream_endpoint_t * stream_endpoint){
892     if (!stream_endpoint) return 0;
893     return stream_endpoint->sep.seid;
894 }
895 uint8_t avdtp_choose_sbc_subbands(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_subbands_bitmap){
896     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
897     uint8_t subbands_bitmap = ((media_codec[1] >> 2) & 0x03) & remote_subbands_bitmap;
898 
899     uint8_t subbands = AVDTP_SBC_SUBBANDS_8;
900     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_8){
901         subbands = AVDTP_SBC_SUBBANDS_8;
902     } else if (subbands_bitmap & AVDTP_SBC_SUBBANDS_4){
903         subbands = AVDTP_SBC_SUBBANDS_4;
904     }
905     return subbands;
906 }
907 
908 uint8_t avdtp_choose_sbc_block_length(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_block_length_bitmap){
909     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
910     uint8_t block_length_bitmap = (media_codec[1] >> 4) & remote_block_length_bitmap;
911 
912     uint8_t block_length = AVDTP_SBC_BLOCK_LENGTH_16;
913     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_16){
914         block_length = AVDTP_SBC_BLOCK_LENGTH_16;
915     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_12){
916         block_length = AVDTP_SBC_BLOCK_LENGTH_12;
917     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_8){
918         block_length = AVDTP_SBC_BLOCK_LENGTH_8;
919     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_4){
920         block_length = AVDTP_SBC_BLOCK_LENGTH_4;
921     }
922     return block_length;
923 }
924 
925 uint8_t avdtp_choose_sbc_sampling_frequency(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_sampling_frequency_bitmap){
926     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
927     uint8_t sampling_frequency_bitmap = (media_codec[0] >> 4) & remote_sampling_frequency_bitmap;
928 
929     uint8_t sampling_frequency = AVDTP_SBC_44100;
930     if (sampling_frequency_bitmap & AVDTP_SBC_48000){
931         sampling_frequency = AVDTP_SBC_48000;
932     } else if (sampling_frequency_bitmap & AVDTP_SBC_44100){
933         sampling_frequency = AVDTP_SBC_44100;
934     } else if (sampling_frequency_bitmap & AVDTP_SBC_32000){
935         sampling_frequency = AVDTP_SBC_32000;
936     } else if (sampling_frequency_bitmap & AVDTP_SBC_16000){
937         sampling_frequency = AVDTP_SBC_16000;
938     }
939     return sampling_frequency;
940 }
941 
942 uint8_t avdtp_choose_sbc_max_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_max_bitpool_value){
943     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
944     return btstack_min(media_codec[3], remote_max_bitpool_value);
945 }
946 
947 uint8_t avdtp_choose_sbc_min_bitpool_value(avdtp_stream_endpoint_t * stream_endpoint, uint8_t remote_min_bitpool_value){
948     uint8_t * media_codec = stream_endpoint->sep.capabilities.media_codec.media_codec_information;
949     return btstack_max(media_codec[2], remote_min_bitpool_value);
950 }