xref: /btstack/src/classic/avdtp_util.c (revision f9a5036a9e6712945a67f85309db53b5acadd485)
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_util.c"
39 
40 #include <stdint.h>
41 #include <string.h>
42 
43 #include "btstack.h"
44 #include "avdtp.h"
45 #include "avdtp_util.h"
46 
47 #define MAX_MEDIA_CODEC_INFORMATION_LENGTH 100
48 
49 
50 /*
51 
52  List of AVDTP_SUBEVENTs sorted by packet handler
53 
54 
55 Sink + Source:
56 - AVDTP_SUBEVENT_SIGNALING_CONNECTION_ESTABLISHED
57 - AVDTP_SUBEVENT_SIGNALING_CONNECTION_RELEASED
58 - AVDTP_SUBEVENT_SIGNALING_SEP_FOUND
59 - AVDTP_SUBEVENT_SIGNALING_ACCEPT
60 - AVDTP_SUBEVENT_SIGNALING_REJECT
61 - AVDTP_SUBEVENT_SIGNALING_GENERAL_REJECT
62 - AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CAPABILITY
63 - AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CAPABILITY
64 - AVDTP_SUBEVENT_SIGNALING_MEDIA_TRANSPORT_CAPABILITY
65 - AVDTP_SUBEVENT_SIGNALING_REPORTING_CAPABILITY
66 - AVDTP_SUBEVENT_SIGNALING_RECOVERY_CAPABILITY
67 - AVDTP_SUBEVENT_SIGNALING_CONTENT_PROTECTION_CAPABILITY
68 - AVDTP_SUBEVENT_SIGNALING_MULTIPLEXING_CAPABILITY
69 - AVDTP_SUBEVENT_SIGNALING_DELAY_REPORTING_CAPABILITY
70 - AVDTP_SUBEVENT_SIGNALING_HEADER_COMPRESSION_CAPABILITY
71 - AVDTP_SUBEVENT_SIGNALING_CAPABILITIES_DONE
72 - AVDTP_SUBEVENT_SIGNALING_SEP_DICOVERY_DONE
73 
74 Source:
75  - AVDTP_SUBEVENT_SIGNALING_DELAY_REPORT
76 
77 Sink or Source based on SEP Type:
78 - AVDTP_SUBEVENT_STREAMING_CONNECTION_ESTABLISHED
79 - AVDTP_SUBEVENT_STREAMING_CONNECTION_RELEASED
80 - AVDTP_SUBEVENT_STREAMING_CAN_SEND_MEDIA_PACKET_NOW
81 - AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CONFIGURATION
82 - AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CONFIGURATION
83 
84 */
85 
86 static const char * avdtp_si_name[] = {
87     "ERROR",
88     "AVDTP_SI_DISCOVER",
89     "AVDTP_SI_GET_CAPABILITIES",
90     "AVDTP_SI_SET_CONFIGURATION",
91     "AVDTP_SI_GET_CONFIGURATION",
92     "AVDTP_SI_RECONFIGURE",
93     "AVDTP_SI_OPEN",
94     "AVDTP_SI_START",
95     "AVDTP_SI_CLOSE",
96     "AVDTP_SI_SUSPEND",
97     "AVDTP_SI_ABORT",
98     "AVDTP_SI_SECURITY_CONTROL",
99     "AVDTP_SI_GET_ALL_CAPABILITIES",
100     "AVDTP_SI_DELAY_REPORT"
101 };
102 const char * avdtp_si2str(uint16_t index){
103     if ((index <= 0) || (index >= sizeof(avdtp_si_name)/sizeof(avdtp_si_name[0]) )) return avdtp_si_name[0];
104     return avdtp_si_name[index];
105 }
106 
107 void avdtp_reset_stream_endpoint(avdtp_stream_endpoint_t * stream_endpoint){
108     stream_endpoint->media_con_handle = 0;
109     stream_endpoint->l2cap_media_cid = 0;
110     stream_endpoint->l2cap_reporting_cid = 0;
111     stream_endpoint->l2cap_recovery_cid = 0;
112 
113     stream_endpoint->connection = NULL;
114     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_IDLE;
115     stream_endpoint->acceptor_config_state = AVDTP_ACCEPTOR_STREAM_CONFIG_IDLE;
116     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_STREAM_CONFIG_IDLE;
117 
118     stream_endpoint->sep.in_use = 0;
119     memset(&stream_endpoint->remote_sep, 0, sizeof(avdtp_sep_t));
120     // memset(&stream_endpoint->remote_capabilities, 0, sizeof(avdtp_capabilities_t));
121     // memset(&stream_endpoint->remote_configuration, 0, sizeof(avdtp_capabilities_t));
122 
123     stream_endpoint->remote_capabilities_bitmap = 0;
124     stream_endpoint->remote_configuration_bitmap = 0;
125 
126     stream_endpoint->media_disconnect = 0;
127     stream_endpoint->media_connect = 0;
128     stream_endpoint->start_stream = 0;
129     stream_endpoint->stop_stream = 0;
130     stream_endpoint->send_stream = 0;
131     stream_endpoint->abort_stream = 0;
132     stream_endpoint->suspend_stream = 0;
133     stream_endpoint->sequence_number = 0;
134 }
135 
136 int get_bit16(uint16_t bitmap, int position){
137     return (bitmap >> position) & 1;
138 }
139 
140 uint16_t store_bit16(uint16_t bitmap, int position, uint8_t value){
141     if (value){
142         bitmap |= 1 << position;
143     } else {
144         bitmap &= ~ (1 << position);
145     }
146     return bitmap;
147 }
148 
149 avdtp_message_type_t avdtp_get_signaling_packet_type(uint8_t * packet){
150     return (avdtp_message_type_t) (packet[0] & 0x03);
151 }
152 
153 int avdtp_read_signaling_header(avdtp_signaling_packet_t * signaling_header, uint8_t * packet, uint16_t size){
154     int pos = 0;
155     if (size < 2) return pos;
156     signaling_header->transaction_label = packet[pos] >> 4;
157     signaling_header->packet_type = (avdtp_packet_type_t)((packet[pos] >> 2) & 0x03);
158     signaling_header->message_type = (avdtp_message_type_t) (packet[pos] & 0x03);
159     pos++;
160     memset(signaling_header->command, 0, sizeof(signaling_header->command));
161     switch (signaling_header->packet_type){
162         case AVDTP_SINGLE_PACKET:
163             signaling_header->num_packets = 0;
164             signaling_header->offset = 0;
165             signaling_header->size = 0;
166             break;
167         case AVDTP_END_PACKET:
168             signaling_header->num_packets = 0;
169             break;
170         case AVDTP_START_PACKET:
171             signaling_header->num_packets = packet[pos++];
172             signaling_header->size = 0;
173             signaling_header->offset = 0;
174             break;
175         case AVDTP_CONTINUE_PACKET:
176             if (signaling_header->num_packets <= 0) {
177                 log_info("    ERROR: wrong num fragmented packets\n");
178                 break;
179             }
180             signaling_header->num_packets--;
181             break;
182     }
183     signaling_header->signal_identifier = (avdtp_signal_identifier_t)(packet[pos++] & 0x3f);
184     return pos;
185 }
186 
187 static bool avdtp_is_basic_capability(int service_category){
188     return (AVDTP_MEDIA_TRANSPORT <= service_category) && (service_category <= AVDTP_MEDIA_CODEC);
189 }
190 
191 int avdtp_pack_service_capabilities(uint8_t *buffer, int size, avdtp_capabilities_t caps, avdtp_service_category_t category) {
192     UNUSED(size);
193 
194     int i;
195     // pos = 0 reserved for length
196     int pos = 1;
197     switch(category){
198         case AVDTP_MEDIA_TRANSPORT:
199         case AVDTP_REPORTING:
200         case AVDTP_DELAY_REPORTING:
201             break;
202         case AVDTP_RECOVERY:
203             buffer[pos++] = caps.recovery.recovery_type; // 0x01=RFC2733
204             buffer[pos++] = caps.recovery.maximum_recovery_window_size;
205             buffer[pos++] = caps.recovery.maximum_number_media_packets;
206             break;
207         case AVDTP_CONTENT_PROTECTION:
208             buffer[pos++] = caps.content_protection.cp_type_value_len + 2;
209             big_endian_store_16(buffer, pos, caps.content_protection.cp_type);
210             pos += 2;
211             (void)memcpy(buffer + pos, caps.content_protection.cp_type_value,
212                          caps.content_protection.cp_type_value_len);
213             break;
214         case AVDTP_HEADER_COMPRESSION:
215             buffer[pos++] = (caps.header_compression.back_ch << 7) | (caps.header_compression.media << 6) | (caps.header_compression.recovery << 5);
216             break;
217         case AVDTP_MULTIPLEXING:
218             buffer[pos++] = caps.multiplexing_mode.fragmentation << 7;
219             for (i=0; i<caps.multiplexing_mode.transport_identifiers_num; i++){
220                 buffer[pos++] = caps.multiplexing_mode.transport_session_identifiers[i] << 7;
221                 buffer[pos++] = caps.multiplexing_mode.tcid[i] << 7;
222                 // media, reporting. recovery
223             }
224             break;
225         case AVDTP_MEDIA_CODEC:
226             buffer[pos++] = ((uint8_t)caps.media_codec.media_type) << 4;
227             buffer[pos++] = (uint8_t)caps.media_codec.media_codec_type;
228             for (i = 0; i<caps.media_codec.media_codec_information_len; i++){
229                 buffer[pos++] = caps.media_codec.media_codec_information[i];
230             }
231             break;
232         default:
233             break;
234     }
235     buffer[0] = pos - 1; // length
236     return pos;
237 }
238 
239 static int avdtp_unpack_service_capabilities_has_errors(avdtp_connection_t * connection, avdtp_signal_identifier_t signal_identifier, avdtp_service_category_t category, uint8_t cap_len){
240     connection->error_code = 0;
241 
242     if ((category == AVDTP_SERVICE_CATEGORY_INVALID_0) ||
243         ((category == AVDTP_SERVICE_CATEGORY_INVALID_FF) && (signal_identifier == AVDTP_SI_RECONFIGURE))){
244         log_info("    ERROR: BAD SERVICE CATEGORY %d\n", category);
245         connection->reject_service_category = category;
246         connection->error_code = BAD_SERV_CATEGORY;
247         return 1;
248     }
249 
250     if (signal_identifier == AVDTP_SI_RECONFIGURE){
251         if ( (category != AVDTP_CONTENT_PROTECTION) && (category != AVDTP_MEDIA_CODEC)){
252             log_info("    ERROR: REJECT CATEGORY, INVALID_CAPABILITIES\n");
253             connection->reject_service_category = category;
254             connection->error_code = INVALID_CAPABILITIES;
255             return 1;
256         }
257     }
258 
259     switch(category){
260         case AVDTP_MEDIA_TRANSPORT:
261             if (cap_len != 0){
262                 log_info("    ERROR: REJECT CATEGORY, BAD_MEDIA_TRANSPORT\n");
263                 connection->reject_service_category = category;
264                 connection->error_code = BAD_MEDIA_TRANSPORT_FORMAT;
265                 return 1;
266             }
267             break;
268         case AVDTP_REPORTING:
269         case AVDTP_DELAY_REPORTING:
270             if (cap_len != 0){
271                 log_info("    ERROR: REJECT CATEGORY, BAD_LENGTH\n");
272                 connection->reject_service_category = category;
273                 connection->error_code = BAD_LENGTH;
274                 return 1;
275             }
276             break;
277         case AVDTP_RECOVERY:
278             if (cap_len != 3){
279                 log_info("    ERROR: REJECT CATEGORY, BAD_MEDIA_TRANSPORT\n");
280                 connection->reject_service_category = category;
281                 connection->error_code = BAD_RECOVERY_FORMAT;
282                 return 1;
283             }
284             break;
285         case AVDTP_CONTENT_PROTECTION:
286             if (cap_len < 2){
287                 log_info("    ERROR: REJECT CATEGORY, BAD_CP_FORMAT\n");
288                 connection->reject_service_category = category;
289                 connection->error_code = BAD_CP_FORMAT;
290                 return 1;
291             }
292             break;
293         case AVDTP_HEADER_COMPRESSION:
294             // TODO: find error code for bad header compression
295             if (cap_len != 1){
296                 log_info("    ERROR: REJECT CATEGORY, BAD_HEADER_COMPRESSION\n");
297                 connection->reject_service_category = category;
298                 connection->error_code = BAD_RECOVERY_FORMAT;
299                 return 1;
300             }
301             break;
302         case AVDTP_MULTIPLEXING:
303             break;
304         case AVDTP_MEDIA_CODEC:
305             break;
306         default:
307             break;
308     }
309     return 0;
310 }
311 
312 uint16_t avdtp_unpack_service_capabilities(avdtp_connection_t * connection, avdtp_signal_identifier_t signal_identifier, avdtp_capabilities_t * caps, uint8_t * packet, uint16_t size){
313 
314     int i;
315 
316     uint16_t registered_service_categories = 0;
317     uint16_t to_process = size;
318 
319     while (to_process >= 2){
320 
321         avdtp_service_category_t category = (avdtp_service_category_t) packet[0];
322         uint8_t cap_len = packet[1];
323         packet     += 2;
324         to_process -= 2;
325 
326         if (cap_len > to_process){
327             connection->reject_service_category = category;
328             connection->error_code = BAD_LENGTH;
329             return 0;
330         }
331 
332         if (avdtp_unpack_service_capabilities_has_errors(connection, signal_identifier, category, cap_len)) return 0;
333 
334         int category_valid = 1;
335 
336         uint8_t * data = packet;
337         uint16_t  pos = 0;
338 
339         switch(category){
340             case AVDTP_RECOVERY:
341                 caps->recovery.recovery_type = data[pos++];
342                 caps->recovery.maximum_recovery_window_size = data[pos++];
343                 caps->recovery.maximum_number_media_packets = data[pos++];
344                 break;
345             case AVDTP_CONTENT_PROTECTION:
346                 caps->content_protection.cp_type = big_endian_read_16(data, 0);
347                 caps->content_protection.cp_type_value_len = cap_len - 2;
348                 // connection->reject_service_category = category;
349                 // connection->error_code = UNSUPPORTED_CONFIGURATION;
350                 // support for content protection goes here
351                 break;
352             case AVDTP_HEADER_COMPRESSION:
353                 caps->header_compression.back_ch  = (data[0] >> 7) & 1;
354                 caps->header_compression.media    = (data[0] >> 6) & 1;
355                 caps->header_compression.recovery = (data[0] >> 5) & 1;
356                 break;
357             case AVDTP_MULTIPLEXING:
358                 caps->multiplexing_mode.fragmentation = (data[pos++] >> 7) & 1;
359                 // read [tsid, tcid] for media, reporting. recovery respectively
360                 caps->multiplexing_mode.transport_identifiers_num = 3;
361                 for (i=0; i<caps->multiplexing_mode.transport_identifiers_num; i++){
362                     caps->multiplexing_mode.transport_session_identifiers[i] = (data[pos++] >> 7) & 1;
363                     caps->multiplexing_mode.tcid[i] = (data[pos++] >> 7) & 1;
364                 }
365                 break;
366             case AVDTP_MEDIA_CODEC:
367                 caps->media_codec.media_type = (avdtp_media_type_t)(data[pos++] >> 4);
368                 caps->media_codec.media_codec_type = (avdtp_media_codec_type_t)(data[pos++]);
369                 caps->media_codec.media_codec_information_len = cap_len - 2;
370                 caps->media_codec.media_codec_information = &data[pos++];
371                 break;
372             case AVDTP_MEDIA_TRANSPORT:
373             case AVDTP_REPORTING:
374             case AVDTP_DELAY_REPORTING:
375                 break;
376             default:
377                 category_valid = 0;
378                 break;
379         }
380 
381         if (category_valid) {
382             registered_service_categories = store_bit16(registered_service_categories, category, 1);
383         }
384 
385         packet     += cap_len;
386         to_process -= cap_len;
387     }
388 
389     return registered_service_categories;
390 }
391 
392 void avdtp_prepare_capabilities(avdtp_signaling_packet_t * signaling_packet, uint8_t transaction_label, uint16_t service_categories, avdtp_capabilities_t capabilities, uint8_t identifier){
393     if (signaling_packet->offset) return;
394     bool basic_capabilities_only = false;
395     signaling_packet->message_type = AVDTP_RESPONSE_ACCEPT_MSG;
396     int i;
397 
398     signaling_packet->size = 0;
399     memset(signaling_packet->command, 0 , sizeof(signaling_packet->command));
400 
401     switch (identifier) {
402         case AVDTP_SI_GET_CAPABILITIES:
403             basic_capabilities_only = true;
404             break;
405         case AVDTP_SI_GET_ALL_CAPABILITIES:
406             break;
407         case AVDTP_SI_SET_CONFIGURATION:
408             signaling_packet->command[signaling_packet->size++] = signaling_packet->acp_seid << 2;
409             signaling_packet->command[signaling_packet->size++] = signaling_packet->int_seid << 2;
410             signaling_packet->message_type = AVDTP_CMD_MSG;
411             break;
412         case AVDTP_SI_RECONFIGURE:
413             signaling_packet->command[signaling_packet->size++] = signaling_packet->acp_seid << 2;
414             signaling_packet->message_type = AVDTP_CMD_MSG;
415             break;
416         default:
417             log_error("avdtp_prepare_capabilities wrong identifier %d", identifier);
418             break;
419     }
420 
421     for (i = AVDTP_MEDIA_TRANSPORT; i <= AVDTP_DELAY_REPORTING; i++){
422         int registered_category = get_bit16(service_categories, i);
423         if (!registered_category && (identifier == AVDTP_SI_SET_CONFIGURATION)){
424             // TODO: introduce bitmap of mandatory categories
425             if (i == AVDTP_MEDIA_TRANSPORT){
426                 registered_category = true;
427             }
428         }
429         // AVDTP_SI_GET_CAPABILITIES reports only basic capabilities (i.e., it skips non-basic categories)
430         if (basic_capabilities_only && !avdtp_is_basic_capability(i)){
431             registered_category = false;
432         }
433 
434         if (registered_category){
435             // service category
436             signaling_packet->command[signaling_packet->size++] = i;
437             signaling_packet->size += avdtp_pack_service_capabilities(signaling_packet->command + signaling_packet->size,
438                     sizeof(signaling_packet->command) - signaling_packet->size, capabilities, (avdtp_service_category_t) i);
439         }
440     }
441     signaling_packet->signal_identifier = (avdtp_signal_identifier_t)identifier;
442     signaling_packet->transaction_label = transaction_label;
443 }
444 
445 int avdtp_signaling_create_fragment(uint16_t cid, avdtp_signaling_packet_t * signaling_packet, uint8_t * out_buffer) {
446     int mtu = l2cap_get_remote_mtu_for_local_cid(cid);
447     int data_len = 0;
448 
449     uint16_t offset = signaling_packet->offset;
450     uint16_t pos = 1;
451 
452     if (offset == 0){
453         if (signaling_packet->size <= (mtu - 2)){
454             signaling_packet->packet_type = AVDTP_SINGLE_PACKET;
455             out_buffer[pos++] = signaling_packet->signal_identifier;
456             data_len = signaling_packet->size;
457         } else {
458             signaling_packet->packet_type = AVDTP_START_PACKET;
459             out_buffer[pos++] = (mtu + signaling_packet->size)/ (mtu-1);
460             out_buffer[pos++] = signaling_packet->signal_identifier;
461             data_len = mtu - 3;
462             signaling_packet->offset = data_len;
463         }
464     } else {
465         int remaining_bytes = signaling_packet->size - offset;
466         if (remaining_bytes <= (mtu - 1)){
467             signaling_packet->packet_type = AVDTP_END_PACKET;
468             data_len = remaining_bytes;
469             signaling_packet->offset = 0;
470         } else{
471             signaling_packet->packet_type = AVDTP_CONTINUE_PACKET;
472             data_len = mtu - 1;
473             signaling_packet->offset += data_len;
474         }
475     }
476     out_buffer[0] = avdtp_header(signaling_packet->transaction_label, signaling_packet->packet_type, signaling_packet->message_type);
477     (void)memcpy(out_buffer + pos, signaling_packet->command + offset,
478                  data_len);
479     pos += data_len;
480     return pos;
481 }
482 
483 
484 void avdtp_signaling_emit_connection_established(uint16_t avdtp_cid, bd_addr_t addr, uint8_t status) {
485     uint8_t event[12];
486     int pos = 0;
487     event[pos++] = HCI_EVENT_AVDTP_META;
488     event[pos++] = sizeof(event) - 2;
489     event[pos++] = AVDTP_SUBEVENT_SIGNALING_CONNECTION_ESTABLISHED;
490     little_endian_store_16(event, pos, avdtp_cid);
491     pos += 2;
492     reverse_bd_addr(addr,&event[pos]);
493     pos += 6;
494     event[pos++] = status;
495     avdtp_emit_sink_and_source(event, pos);
496 }
497 
498 void avdtp_signaling_emit_connection_released(uint16_t avdtp_cid) {
499     uint8_t event[5];
500     int pos = 0;
501     event[pos++] = HCI_EVENT_AVDTP_META;
502     event[pos++] = sizeof(event) - 2;
503     event[pos++] = AVDTP_SUBEVENT_SIGNALING_CONNECTION_RELEASED;
504     little_endian_store_16(event, pos, avdtp_cid);
505     pos += 2;
506     avdtp_emit_sink_and_source(event, pos);
507 }
508 
509 void avdtp_signaling_emit_sep(uint16_t avdtp_cid, avdtp_sep_t sep) {
510     uint8_t event[9];
511     int pos = 0;
512     event[pos++] = HCI_EVENT_AVDTP_META;
513     event[pos++] = sizeof(event) - 2;
514     event[pos++] = AVDTP_SUBEVENT_SIGNALING_SEP_FOUND;
515     little_endian_store_16(event, pos, avdtp_cid);
516     pos += 2;
517     event[pos++] = sep.seid;
518     event[pos++] = sep.in_use;
519     event[pos++] = sep.media_type;
520     event[pos++] = sep.type;
521     avdtp_emit_sink_and_source(event, pos);
522 }
523 
524 void avdtp_signaling_emit_sep_done(uint16_t avdtp_cid) {
525     uint8_t event[5];
526     int pos = 0;
527     event[pos++] = HCI_EVENT_AVDTP_META;
528     event[pos++] = sizeof(event) - 2;
529     event[pos++] = AVDTP_SUBEVENT_SIGNALING_SEP_DICOVERY_DONE;
530     little_endian_store_16(event, pos, avdtp_cid);
531     pos += 2;
532     avdtp_emit_sink_and_source(event, pos);
533 }
534 
535 void avdtp_signaling_emit_accept(uint16_t avdtp_cid, uint8_t local_seid, avdtp_signal_identifier_t identifier, bool is_initiator) {
536     uint8_t event[8];
537     int pos = 0;
538     event[pos++] = HCI_EVENT_AVDTP_META;
539     event[pos++] = sizeof(event) - 2;
540     event[pos++] = AVDTP_SUBEVENT_SIGNALING_ACCEPT;
541     little_endian_store_16(event, pos, avdtp_cid);
542     pos += 2;
543     event[pos++] = local_seid;
544     event[pos++] = is_initiator ? 1 : 0;
545     event[pos++] = identifier;
546     avdtp_emit_sink_and_source(event, pos);
547 }
548 
549 void avdtp_signaling_emit_reject(uint16_t avdtp_cid, uint8_t local_seid, avdtp_signal_identifier_t identifier, bool is_initiator) {
550     uint8_t event[8];
551     int pos = 0;
552     event[pos++] = HCI_EVENT_AVDTP_META;
553     event[pos++] = sizeof(event) - 2;
554     event[pos++] = AVDTP_SUBEVENT_SIGNALING_REJECT;
555     little_endian_store_16(event, pos, avdtp_cid);
556     pos += 2;
557     event[pos++] = local_seid;
558     event[pos++] = is_initiator ? 1 : 0;
559     event[pos++] = identifier;
560     avdtp_emit_sink_and_source(event, pos);
561 }
562 
563 void avdtp_signaling_emit_general_reject(uint16_t avdtp_cid, uint8_t local_seid, avdtp_signal_identifier_t identifier, bool is_initiator) {
564     uint8_t event[8];
565     int pos = 0;
566     event[pos++] = HCI_EVENT_AVDTP_META;
567     event[pos++] = sizeof(event) - 2;
568     event[pos++] = AVDTP_SUBEVENT_SIGNALING_GENERAL_REJECT;
569     little_endian_store_16(event, pos, avdtp_cid);
570     pos += 2;
571     event[pos++] = local_seid;
572     event[pos++] = is_initiator ? 1 : 0;
573     event[pos++] = identifier;
574     avdtp_emit_sink_and_source(event, pos);
575 }
576 
577 static inline void
578 avdtp_signaling_emit_capability(uint8_t capability_subevent_id, uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid) {
579     uint8_t event[7];
580     int pos = 0;
581     event[pos++] = HCI_EVENT_AVDTP_META;
582     event[pos++] = sizeof(event) - 2;
583     event[pos++] = capability_subevent_id;
584     little_endian_store_16(event, pos, avdtp_cid);
585     pos += 2;
586     event[pos++] = local_seid;
587     event[pos++] = remote_seid;
588     avdtp_emit_sink_and_source(event, pos);
589 }
590 
591 static void avdtp_signaling_emit_media_codec_sbc_capability(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid,
592                                                             adtvp_media_codec_capabilities_t media_codec) {
593     uint8_t event[15];
594     int pos = 0;
595     event[pos++] = HCI_EVENT_AVDTP_META;
596     event[pos++] = sizeof(event) - 2;
597     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CAPABILITY;
598     little_endian_store_16(event, pos, avdtp_cid);
599     pos += 2;
600     event[pos++] = local_seid;
601     event[pos++] = remote_seid;
602     event[pos++] = media_codec.media_type;
603     event[pos++] = media_codec.media_codec_information[0] >> 4;
604     event[pos++] = media_codec.media_codec_information[0] & 0x0F;
605     event[pos++] = media_codec.media_codec_information[1] >> 4;
606     event[pos++] = (media_codec.media_codec_information[1] & 0x0F) >> 2;
607     event[pos++] = media_codec.media_codec_information[1] & 0x03;
608     event[pos++] = media_codec.media_codec_information[2];
609     event[pos++] = media_codec.media_codec_information[3];
610     avdtp_emit_sink_and_source(event, pos);
611 }
612 
613 static void avdtp_signaling_emit_media_codec_other_capability(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid,
614                                                   adtvp_media_codec_capabilities_t media_codec) {
615     uint8_t event[MAX_MEDIA_CODEC_INFORMATION_LENGTH + 12];
616     int pos = 0;
617     event[pos++] = HCI_EVENT_AVDTP_META;
618     event[pos++] = sizeof(event) - 2;
619     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CAPABILITY;
620     little_endian_store_16(event, pos, avdtp_cid);
621     pos += 2;
622     event[pos++] = local_seid;
623     event[pos++] = remote_seid;
624     event[pos++] = media_codec.media_type;
625     little_endian_store_16(event, pos, media_codec.media_codec_type);
626     pos += 2;
627     little_endian_store_16(event, pos, media_codec.media_codec_information_len);
628     pos += 2;
629     (void)memcpy(event + pos, media_codec.media_codec_information,
630                  btstack_min(media_codec.media_codec_information_len, MAX_MEDIA_CODEC_INFORMATION_LENGTH));
631     avdtp_emit_sink_and_source(event, pos);
632 }
633 
634 static void
635 avdtp_signaling_emit_media_transport_capability(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid) {
636     avdtp_signaling_emit_capability(AVDTP_SUBEVENT_SIGNALING_MEDIA_TRANSPORT_CAPABILITY, avdtp_cid, local_seid,
637                                     remote_seid);
638 }
639 
640 static void avdtp_signaling_emit_reporting_capability(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid) {
641     avdtp_signaling_emit_capability(AVDTP_SUBEVENT_SIGNALING_REPORTING_CAPABILITY, avdtp_cid, local_seid, remote_seid);
642 }
643 
644 static void
645 avdtp_signaling_emit_delay_reporting_capability(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid) {
646     avdtp_signaling_emit_capability(AVDTP_SUBEVENT_SIGNALING_DELAY_REPORTING_CAPABILITY, avdtp_cid, local_seid,
647                                     remote_seid);
648 }
649 
650 static void avdtp_signaling_emit_recovery_capability(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid,
651                                                      avdtp_recovery_capabilities_t *recovery) {
652     uint8_t event[10];
653     int pos = 0;
654     event[pos++] = HCI_EVENT_AVDTP_META;
655     event[pos++] = sizeof(event) - 2;
656     event[pos++] = AVDTP_SUBEVENT_SIGNALING_RECOVERY_CAPABILITY;
657     little_endian_store_16(event, pos, avdtp_cid);
658     pos += 2;
659     event[pos++] = local_seid;
660     event[pos++] = remote_seid;
661     event[pos++] = recovery->recovery_type;
662     event[pos++] = recovery->maximum_recovery_window_size;
663     event[pos++] = recovery->maximum_number_media_packets;
664     avdtp_emit_sink_and_source(event, pos);
665 }
666 
667 static void
668 avdtp_signaling_emit_content_protection_capability(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid,
669                                                    adtvp_content_protection_t *content_protection) {
670     uint8_t event[22];
671     int pos = 0;
672     event[pos++] = HCI_EVENT_AVDTP_META;
673     event[pos++] = sizeof(event) - 2;
674     event[pos++] = AVDTP_SUBEVENT_SIGNALING_CONTENT_PROTECTION_CAPABILITY;
675     little_endian_store_16(event, pos, avdtp_cid);
676     pos += 2;
677     event[pos++] = local_seid;
678     event[pos++] = remote_seid;
679 
680     little_endian_store_16(event, pos, content_protection->cp_type);
681     pos += 2;
682     little_endian_store_16(event, pos, content_protection->cp_type_value_len);
683     pos += 2;
684 
685     //TODO: reserve place for value
686     if (content_protection->cp_type_value_len < 10){
687         (void)memcpy(event + pos, content_protection->cp_type_value,
688                      content_protection->cp_type_value_len);
689     }
690     avdtp_emit_sink_and_source(event, pos);
691 }
692 
693 
694 static void
695 avdtp_signaling_emit_header_compression_capability(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid,
696                                                    avdtp_header_compression_capabilities_t *header_compression) {
697     uint8_t event[10];
698     int pos = 0;
699     event[pos++] = HCI_EVENT_AVDTP_META;
700     event[pos++] = sizeof(event) - 2;
701     event[pos++] = AVDTP_SUBEVENT_SIGNALING_HEADER_COMPRESSION_CAPABILITY;
702     little_endian_store_16(event, pos, avdtp_cid);
703     pos += 2;
704     event[pos++] = local_seid;
705     event[pos++] = remote_seid;
706     event[pos++] = header_compression->back_ch;
707     event[pos++] = header_compression->media;
708     event[pos++] = header_compression->recovery;
709     avdtp_emit_sink_and_source(event, pos);
710 }
711 
712 static void
713 avdtp_signaling_emit_content_multiplexing_capability(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid,
714                                                      avdtp_multiplexing_mode_capabilities_t *multiplexing_mode) {
715     uint8_t event[15];
716     int pos = 0;
717     event[pos++] = HCI_EVENT_AVDTP_META;
718     event[pos++] = sizeof(event) - 2;
719     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MULTIPLEXING_CAPABILITY;
720     little_endian_store_16(event, pos, avdtp_cid);
721     pos += 2;
722     event[pos++] = local_seid;
723     event[pos++] = remote_seid;
724 
725     event[pos++] = multiplexing_mode->fragmentation;
726     event[pos++] = multiplexing_mode->transport_identifiers_num;
727 
728     int i;
729     for (i = 0; i < 3; i++){
730         event[pos++] = multiplexing_mode->transport_session_identifiers[i];
731     }
732     for (i = 0; i < 3; i++){
733         event[pos++] = multiplexing_mode->tcid[i];
734     }
735     avdtp_emit_sink_and_source(event, pos);
736 }
737 
738 static void avdtp_signaling_emit_capability_done(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid) {
739     uint8_t event[7];
740     int pos = 0;
741     event[pos++] = HCI_EVENT_AVDTP_META;
742     event[pos++] = sizeof(event) - 2;
743     event[pos++] = AVDTP_SUBEVENT_SIGNALING_CAPABILITIES_DONE;
744     little_endian_store_16(event, pos, avdtp_cid);
745     pos += 2;
746     event[pos++] = local_seid;
747     event[pos++] = remote_seid;
748     avdtp_emit_sink_and_source(event, pos);
749 }
750 
751 // emit events for all capabilities incl. final done event
752 void avdtp_signaling_emit_capabilities(uint16_t avdtp_cid, uint8_t local_seid, uint8_t remote_seid, avdtp_capabilities_t *capabilities,
753                                        uint16_t registered_service_categories) {
754     if (get_bit16(registered_service_categories, AVDTP_MEDIA_CODEC)){
755         switch (capabilities->media_codec.media_codec_type){
756             case AVDTP_CODEC_SBC:
757                 avdtp_signaling_emit_media_codec_sbc_capability(avdtp_cid, local_seid, remote_seid, capabilities->media_codec);
758                 break;
759             default:
760                 avdtp_signaling_emit_media_codec_other_capability(avdtp_cid, local_seid, remote_seid, capabilities->media_codec);
761                 break;
762         }
763     }
764 
765     if (get_bit16(registered_service_categories, AVDTP_MEDIA_TRANSPORT)){
766         avdtp_signaling_emit_media_transport_capability(avdtp_cid, local_seid, remote_seid);
767     }
768     if (get_bit16(registered_service_categories, AVDTP_REPORTING)){
769         avdtp_signaling_emit_reporting_capability(avdtp_cid, local_seid, remote_seid);
770     }
771     if (get_bit16(registered_service_categories, AVDTP_RECOVERY)){
772         avdtp_signaling_emit_recovery_capability(avdtp_cid, local_seid, remote_seid, &capabilities->recovery);
773     }
774     if (get_bit16(registered_service_categories, AVDTP_CONTENT_PROTECTION)){
775         avdtp_signaling_emit_content_protection_capability(avdtp_cid, local_seid, remote_seid,
776                                                            &capabilities->content_protection);
777     }
778     if (get_bit16(registered_service_categories, AVDTP_HEADER_COMPRESSION)){
779         avdtp_signaling_emit_header_compression_capability(avdtp_cid, local_seid, remote_seid,
780                                                            &capabilities->header_compression);
781     }
782     if (get_bit16(registered_service_categories, AVDTP_MULTIPLEXING)){
783         avdtp_signaling_emit_content_multiplexing_capability(avdtp_cid, local_seid, remote_seid,
784                                                              &capabilities->multiplexing_mode);
785     }
786     if (get_bit16(registered_service_categories, AVDTP_DELAY_REPORTING)){
787         avdtp_signaling_emit_delay_reporting_capability(avdtp_cid, local_seid, remote_seid);
788     }
789     avdtp_signaling_emit_capability_done(avdtp_cid, local_seid, remote_seid);
790 }
791 
792 void avdtp_signaling_emit_media_codec_sbc(avdtp_stream_endpoint_t *stream_endpoint, uint16_t avdtp_cid,
793                                      avdtp_media_type_t media_type, const uint8_t *media_codec_information,
794                                      uint8_t reconfigure) {
795 
796     btstack_packet_handler_t packet_handler = avdtp_packet_handler_for_stream_endpoint(stream_endpoint);
797     uint8_t local_seid = avdtp_local_seid(stream_endpoint);
798     uint8_t remote_seid = avdtp_remote_seid(stream_endpoint);
799 
800     uint8_t event[16 + 2];
801     int pos = 0;
802     event[pos++] = HCI_EVENT_AVDTP_META;
803     event[pos++] = sizeof(event) - 2;
804 
805     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CONFIGURATION;
806     little_endian_store_16(event, pos, avdtp_cid);
807     pos += 2;
808     event[pos++] = local_seid;
809     event[pos++] = remote_seid;
810     event[pos++] = reconfigure;
811 
812 
813     uint8_t sampling_frequency_bitmap = media_codec_information[0] >> 4;
814     uint8_t channel_mode_bitmap = media_codec_information[0] & 0x0F;
815     uint8_t block_length_bitmap = media_codec_information[1] >> 4;
816     uint8_t subbands_bitmap = (media_codec_information[1] & 0x0F) >> 2;
817 
818     uint8_t num_channels = 0;
819     if ((channel_mode_bitmap & AVDTP_SBC_JOINT_STEREO) ||
820         (channel_mode_bitmap & AVDTP_SBC_STEREO) ||
821         (channel_mode_bitmap & AVDTP_SBC_DUAL_CHANNEL)) {
822         num_channels = 2;
823     } else if (channel_mode_bitmap & AVDTP_SBC_MONO) {
824         num_channels = 1;
825     }
826 
827     uint16_t sampling_frequency = 0;
828     if (sampling_frequency_bitmap & AVDTP_SBC_48000) {
829         sampling_frequency = 48000;
830     } else if (sampling_frequency_bitmap & AVDTP_SBC_44100) {
831         sampling_frequency = 44100;
832     } else if (sampling_frequency_bitmap & AVDTP_SBC_32000) {
833         sampling_frequency = 32000;
834     } else if (sampling_frequency_bitmap & AVDTP_SBC_16000) {
835         sampling_frequency = 16000;
836     }
837 
838     uint8_t subbands = 0;
839     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_8){
840         subbands = 8;
841     } else if (subbands_bitmap & AVDTP_SBC_SUBBANDS_4){
842         subbands = 4;
843     }
844 
845     uint8_t block_length = 0;
846     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_16){
847         block_length = 16;
848     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_12){
849         block_length = 12;
850     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_8){
851         block_length = 8;
852     } else if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_4){
853         block_length = 4;
854     }
855 
856     event[pos++] = media_type;
857     little_endian_store_16(event, pos, sampling_frequency);
858     pos += 2;
859 
860     event[pos++] = channel_mode_bitmap;
861     event[pos++] = num_channels;
862     event[pos++] = block_length;
863     event[pos++] = subbands;
864     event[pos++] = media_codec_information[1] & 0x03;
865     event[pos++] = media_codec_information[2];
866     event[pos++] = media_codec_information[3];
867     (*packet_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event));
868 }
869 
870 void
871 avdtp_signaling_emit_media_codec_other(avdtp_stream_endpoint_t *stream_endpoint, uint16_t avdtp_cid,
872                                        adtvp_media_codec_capabilities_t * media_codec, uint8_t reconfigure) {
873 
874     btstack_packet_handler_t packet_handler = avdtp_packet_handler_for_stream_endpoint(stream_endpoint);
875     uint8_t local_seid = avdtp_local_seid(stream_endpoint);
876     uint8_t remote_seid = avdtp_remote_seid(stream_endpoint);
877 
878     uint8_t event[MAX_MEDIA_CODEC_INFORMATION_LENGTH + 13];
879     int pos = 0;
880     event[pos++] = HCI_EVENT_AVDTP_META;
881     event[pos++] = sizeof(event) - 2;
882     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CONFIGURATION;
883     little_endian_store_16(event, pos, avdtp_cid);
884     pos += 2;
885     event[pos++] = local_seid;
886     event[pos++] = remote_seid;
887     event[pos++] = reconfigure;
888     event[pos++] = media_codec->media_type;
889     little_endian_store_16(event, pos, media_codec->media_codec_type);
890     pos += 2;
891     little_endian_store_16(event, pos, media_codec->media_codec_information_len);
892     pos += 2;
893 
894     int media_codec_len = btstack_min(MAX_MEDIA_CODEC_INFORMATION_LENGTH, media_codec->media_codec_information_len);
895     (void)memcpy(event + pos, media_codec->media_codec_information, media_codec_len);
896 
897     (*packet_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event));
898 }
899 
900 void avdtp_signaling_emit_delay(uint16_t avdtp_cid, uint8_t local_seid, uint16_t delay) {
901     uint8_t event[8];
902     int pos = 0;
903     event[pos++] = HCI_EVENT_AVDTP_META;
904     event[pos++] = sizeof(event) - 2;
905     event[pos++] = AVDTP_SUBEVENT_SIGNALING_DELAY_REPORT;
906     little_endian_store_16(event, pos, avdtp_cid);
907     pos += 2;
908     event[pos++] = local_seid;
909     little_endian_store_16(event, pos, delay);
910     pos += 2;
911     avdtp_emit_source(event, sizeof(event));
912 }
913 
914 void avdtp_signaling_emit_media_codec_sbc_configuration(avdtp_stream_endpoint_t *stream_endpoint, uint16_t avdtp_cid,
915                                                         avdtp_media_type_t media_type,
916                                                         const uint8_t *media_codec_information) {
917     avdtp_signaling_emit_media_codec_sbc(stream_endpoint, avdtp_cid, media_type,
918                                          media_codec_information, 0);
919 }
920 
921 void avdtp_signaling_emit_media_codec_sbc_reconfiguration(avdtp_stream_endpoint_t *stream_endpoint, uint16_t avdtp_cid,
922                                                           avdtp_media_type_t media_type,
923                                                           const uint8_t *media_codec_information) {
924     avdtp_signaling_emit_media_codec_sbc(stream_endpoint, avdtp_cid, media_type,
925                                          media_codec_information, 1);
926 }
927 
928 void avdtp_signaling_emit_media_codec_other_configuration(avdtp_stream_endpoint_t *stream_endpoint, uint16_t avdtp_cid,
929                                                           adtvp_media_codec_capabilities_t * media_codec) {
930     avdtp_signaling_emit_media_codec_other(stream_endpoint, avdtp_cid, media_codec, 0);
931 }
932 
933 void avdtp_signaling_emit_media_codec_other_reconfiguration(avdtp_stream_endpoint_t *stream_endpoint, uint16_t avdtp_cid,
934                                                        adtvp_media_codec_capabilities_t * media_codec) {
935     avdtp_signaling_emit_media_codec_other(stream_endpoint, avdtp_cid, media_codec, 1);
936 }
937 
938 void avdtp_signaling_emit_configuration(avdtp_stream_endpoint_t *stream_endpoint, uint16_t avdtp_cid,
939                                         avdtp_capabilities_t *configuration, uint16_t configured_service_categories) {
940 
941     if (get_bit16(configured_service_categories, AVDTP_MEDIA_CODEC)){
942         switch (configuration->media_codec.media_codec_type){
943             case AVDTP_CODEC_SBC:
944                 avdtp_signaling_emit_media_codec_sbc_configuration(
945                         stream_endpoint, avdtp_cid,
946                         configuration->media_codec.media_type,
947                         configuration->media_codec.media_codec_information);
948                 break;
949             default:
950                 avdtp_signaling_emit_media_codec_other_configuration(stream_endpoint, avdtp_cid,
951                                                                      &configuration->media_codec);
952                 break;
953         }
954     }
955 }
956 
957 void avdtp_streaming_emit_connection_established(avdtp_stream_endpoint_t *stream_endpoint, uint8_t status) {
958     uint8_t event[14];
959     int pos = 0;
960     event[pos++] = HCI_EVENT_AVDTP_META;
961     event[pos++] = sizeof(event) - 2;
962     event[pos++] = AVDTP_SUBEVENT_STREAMING_CONNECTION_ESTABLISHED;
963     little_endian_store_16(event, pos, stream_endpoint->connection->avdtp_cid);
964     pos += 2;
965     reverse_bd_addr(stream_endpoint->connection->remote_addr, &event[pos]);
966     pos += 6;
967     event[pos++] = avdtp_local_seid(stream_endpoint);
968     event[pos++] = avdtp_remote_seid(stream_endpoint);
969     event[pos++] = status;
970 
971     btstack_packet_handler_t packet_handler = avdtp_packet_handler_for_stream_endpoint(stream_endpoint);
972     (*packet_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event));
973 }
974 
975 void avdtp_streaming_emit_connection_released(avdtp_stream_endpoint_t *stream_endpoint, uint16_t avdtp_cid, uint8_t local_seid) {
976     uint8_t event[6];
977     int pos = 0;
978     event[pos++] = HCI_EVENT_AVDTP_META;
979     event[pos++] = sizeof(event) - 2;
980     event[pos++] = AVDTP_SUBEVENT_STREAMING_CONNECTION_RELEASED;
981     little_endian_store_16(event, pos, avdtp_cid);
982     pos += 2;
983     event[pos++] = local_seid;
984 
985     btstack_packet_handler_t packet_handler = avdtp_packet_handler_for_stream_endpoint(stream_endpoint);
986     (*packet_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event));
987 }
988 
989 void avdtp_streaming_emit_can_send_media_packet_now(avdtp_stream_endpoint_t *stream_endpoint, uint16_t sequence_number) {
990     uint8_t event[8];
991     int pos = 0;
992     event[pos++] = HCI_EVENT_AVDTP_META;
993     event[pos++] = sizeof(event) - 2;
994     event[pos++] = AVDTP_SUBEVENT_STREAMING_CAN_SEND_MEDIA_PACKET_NOW;
995     little_endian_store_16(event, pos, stream_endpoint->connection->avdtp_cid);
996     pos += 2;
997     event[pos++] = avdtp_local_seid(stream_endpoint);
998     little_endian_store_16(event, pos, sequence_number);
999     pos += 2;
1000 
1001     btstack_packet_handler_t packet_handler = avdtp_packet_handler_for_stream_endpoint(stream_endpoint);
1002     (*packet_handler)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1003 }
1004 
1005 uint8_t avdtp_request_can_send_now_acceptor(avdtp_connection_t * connection, uint16_t l2cap_cid){
1006     if (!connection) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1007     connection->wait_to_send_acceptor = 1;
1008     l2cap_request_can_send_now_event(l2cap_cid);
1009     return ERROR_CODE_SUCCESS;
1010 }
1011 
1012 uint8_t avdtp_request_can_send_now_initiator(avdtp_connection_t * connection, uint16_t l2cap_cid){
1013     if (!connection) return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER;
1014     connection->wait_to_send_initiator = 1;
1015     l2cap_request_can_send_now_event(l2cap_cid);
1016     return ERROR_CODE_SUCCESS;
1017 }
1018 
1019 uint8_t avdtp_local_seid(avdtp_stream_endpoint_t * stream_endpoint){
1020     if (!stream_endpoint) return 0;
1021     return stream_endpoint->sep.seid;
1022 
1023 }
1024 
1025 uint8_t avdtp_remote_seid(avdtp_stream_endpoint_t * stream_endpoint){
1026     if (!stream_endpoint) return AVDTP_INVALID_SEP_SEID;
1027     return stream_endpoint->remote_sep.seid;
1028 }
1029 
1030 // helper for A2DP
1031 
1032 void a2dp_replace_subevent_id_and_emit_cmd(btstack_packet_handler_t callback, uint8_t * packet, uint16_t size, uint8_t subevent_id){
1033     UNUSED(size);
1034     btstack_assert(callback != NULL);
1035     packet[0] = HCI_EVENT_A2DP_META;
1036     packet[2] = subevent_id;
1037     (*callback)(HCI_EVENT_PACKET, 0, packet, size);
1038 }
1039 
1040 void a2dp_emit_streaming_connection_established(btstack_packet_handler_t callback, uint8_t * packet, uint16_t size, uint8_t status){
1041     btstack_assert(callback != NULL);
1042     packet[0] = HCI_EVENT_A2DP_META;
1043     packet[2] = A2DP_SUBEVENT_STREAM_ESTABLISHED;
1044     packet[12] = status;
1045     (*callback)(HCI_EVENT_PACKET, 0, packet, size);
1046 }
1047 
1048 void a2dp_emit_signaling_connection_established(btstack_packet_handler_t callback, uint8_t * packet, uint16_t size, uint8_t status){
1049     btstack_assert(callback != NULL);
1050     packet[0] = HCI_EVENT_A2DP_META;
1051     packet[2] = A2DP_SUBEVENT_SIGNALING_CONNECTION_ESTABLISHED;
1052     packet[10] = status;
1053     (*callback)(HCI_EVENT_PACKET, 0, packet, size);
1054 }
1055 
1056 void a2dp_emit_stream_event(btstack_packet_handler_t callback, uint16_t cid, uint8_t local_seid, uint8_t subevent_id){
1057     uint8_t event[6];
1058     int pos = 0;
1059     event[pos++] = HCI_EVENT_A2DP_META;
1060     event[pos++] = sizeof(event) - 2;
1061     event[pos++] = subevent_id;
1062     little_endian_store_16(event, pos, cid);
1063     pos += 2;
1064     event[pos++] = local_seid;
1065     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
1066 }
1067