xref: /btstack/src/classic/avdtp_util.c (revision f9f2075ceac5e9dc08e9abea437e43d733a3a0ea)
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 
39 #include <stdint.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44 
45 #include "btstack.h"
46 #include "avdtp.h"
47 #include "avdtp_util.h"
48 
49 inline uint8_t avdtp_header(uint8_t tr_label, avdtp_packet_type_t packet_type, avdtp_message_type_t msg_type){
50     return (tr_label<<4) | ((uint8_t)packet_type<<2) | (uint8_t)msg_type;
51 }
52 
53 avdtp_stream_endpoint_t * get_avdtp_stream_endpoint_with_seid(uint8_t seid){
54     btstack_linked_list_iterator_t it;
55     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &stream_endpoints);
56     while (btstack_linked_list_iterator_has_next(&it)){
57         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
58         if (stream_endpoint->sep.seid == seid){
59             return stream_endpoint;
60         }
61     }
62     return NULL;
63 }
64 
65 avdtp_stream_endpoint_t * get_avdtp_stream_endpoint_associated_with_acp_seid(uint16_t acp_seid){
66     btstack_linked_list_iterator_t it;
67     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &stream_endpoints);
68     while (btstack_linked_list_iterator_has_next(&it)){
69         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
70         if (stream_endpoint->remote_sep_index >= 0 && stream_endpoint->remote_sep_index < MAX_NUM_SEPS){
71             if (stream_endpoint->remote_seps[stream_endpoint->remote_sep_index].seid == acp_seid){
72                 return stream_endpoint;
73             }
74         }
75     }
76     return NULL;
77 }
78 
79 int get_bit16(uint16_t bitmap, int position){
80     return (bitmap >> position) & 1;
81 }
82 
83 uint8_t store_bit16(uint16_t bitmap, int position, uint8_t value){
84     if (value){
85         bitmap |= 1 << position;
86     } else {
87         bitmap &= ~ (1 << position);
88     }
89     return bitmap;
90 }
91 
92 int avdtp_read_signaling_header(avdtp_signaling_packet_t * signaling_header, uint8_t * packet, uint16_t size){
93     int pos = 0;
94     if (size < 2) return pos;
95     signaling_header->transaction_label = packet[pos] >> 4;
96     signaling_header->packet_type = (avdtp_packet_type_t)((packet[pos] >> 2) & 0x03);
97     signaling_header->message_type = (avdtp_message_type_t) (packet[pos] & 0x03);
98     pos++;
99     memset(signaling_header->command, 0, sizeof(signaling_header->command));
100     switch (signaling_header->packet_type){
101         case AVDTP_SINGLE_PACKET:
102             signaling_header->num_packets = 0;
103             signaling_header->offset = 0;
104             signaling_header->size = 0;
105             break;
106         case AVDTP_END_PACKET:
107             signaling_header->num_packets = 0;
108             break;
109         case AVDTP_START_PACKET:
110             signaling_header->num_packets = packet[pos++];
111             signaling_header->size = 0;
112             signaling_header->offset = 0;
113             break;
114         case AVDTP_CONTINUE_PACKET:
115             if (signaling_header->num_packets <= 0) {
116                 printf("    ERROR: wrong num fragmented packets\n");
117                 break;
118             }
119             signaling_header->num_packets--;
120             break;
121     }
122     signaling_header->signal_identifier = packet[pos++] & 0x3f;
123     return pos;
124 }
125 
126 int avdtp_pack_service_capabilities(uint8_t * buffer, int size, avdtp_capabilities_t caps, avdtp_service_category_t category, uint8_t pack_all_capabilities){
127     UNUSED(size);
128 
129     int i;
130     // pos = 0 reserved for length
131     int pos = 1;
132     switch(category){
133         case AVDTP_MEDIA_TRANSPORT:
134         case AVDTP_REPORTING:
135             break;
136         case AVDTP_DELAY_REPORTING:
137             if (!pack_all_capabilities) break;
138             break;
139         case AVDTP_RECOVERY:
140             buffer[pos++] = caps.recovery.recovery_type; // 0x01=RFC2733
141             buffer[pos++] = caps.recovery.maximum_recovery_window_size;
142             buffer[pos++] = caps.recovery.maximum_number_media_packets;
143             break;
144         case AVDTP_CONTENT_PROTECTION:
145             buffer[pos++] = caps.content_protection.cp_type_value_len + 2;
146             big_endian_store_16(buffer, pos, caps.content_protection.cp_type);
147             pos += 2;
148             memcpy(buffer+pos, caps.content_protection.cp_type_value, caps.content_protection.cp_type_value_len);
149             break;
150         case AVDTP_HEADER_COMPRESSION:
151             buffer[pos++] = (caps.header_compression.back_ch << 7) | (caps.header_compression.media << 6) | (caps.header_compression.recovery << 5);
152             break;
153         case AVDTP_MULTIPLEXING:
154             buffer[pos++] = caps.multiplexing_mode.fragmentation << 7;
155             for (i=0; i<caps.multiplexing_mode.transport_identifiers_num; i++){
156                 buffer[pos++] = caps.multiplexing_mode.transport_session_identifiers[i] << 7;
157                 buffer[pos++] = caps.multiplexing_mode.tcid[i] << 7;
158                 // media, reporting. recovery
159             }
160             break;
161         case AVDTP_MEDIA_CODEC:
162             buffer[pos++] = ((uint8_t)caps.media_codec.media_type) << 4;
163             buffer[pos++] = (uint8_t)caps.media_codec.media_codec_type;
164             for (i = 0; i<caps.media_codec.media_codec_information_len; i++){
165                 buffer[pos++] = caps.media_codec.media_codec_information[i];
166             }
167             break;
168         default:
169             break;
170     }
171     buffer[0] = pos - 1; // length
172     return pos;
173 }
174 
175 static int avdtp_unpack_service_capabilities_has_errors(avdtp_connection_t * connection, avdtp_service_category_t category, uint8_t cap_len){
176     connection->error_code = 0;
177 
178     if (category == AVDTP_SERVICE_CATEGORY_INVALID_0 ||
179         (category == AVDTP_SERVICE_CATEGORY_INVALID_FF && connection->signaling_packet.signal_identifier == AVDTP_SI_RECONFIGURE)){
180         printf("    ERROR: BAD SERVICE CATEGORY %d\n", category);
181         connection->reject_service_category = category;
182         connection->error_code = BAD_SERV_CATEGORY;
183         return 1;
184     }
185 
186     if (connection->signaling_packet.signal_identifier == AVDTP_SI_RECONFIGURE){
187         if (category != AVDTP_CONTENT_PROTECTION && category != AVDTP_MEDIA_CODEC){
188             printf("    ERROR: REJECT CATEGORY, INVALID_CAPABILITIES\n");
189             connection->reject_service_category = category;
190             connection->error_code = INVALID_CAPABILITIES;
191             return 1;
192         }
193     }
194 
195     switch(category){
196         case AVDTP_MEDIA_TRANSPORT:
197             if (cap_len != 0){
198                 printf("    ERROR: REJECT CATEGORY, BAD_MEDIA_TRANSPORT\n");
199                 connection->reject_service_category = category;
200                 connection->error_code = BAD_MEDIA_TRANSPORT_FORMAT;
201                 return 1;
202             }
203             break;
204         case AVDTP_REPORTING:
205         case AVDTP_DELAY_REPORTING:
206             if (cap_len != 0){
207                 printf("    ERROR: REJECT CATEGORY, BAD_LENGTH\n");
208                 connection->reject_service_category = category;
209                 connection->error_code = BAD_LENGTH;
210                 return 1;
211             }
212             break;
213         case AVDTP_RECOVERY:
214             if (cap_len < 3){
215                 printf("    ERROR: REJECT CATEGORY, BAD_MEDIA_TRANSPORT\n");
216                 connection->reject_service_category = category;
217                 connection->error_code = BAD_RECOVERY_FORMAT;
218                 return 1;
219             }
220             break;
221         case AVDTP_CONTENT_PROTECTION:
222             if (cap_len < 2){
223                 printf("    ERROR: REJECT CATEGORY, BAD_CP_FORMAT\n");
224                 connection->reject_service_category = category;
225                 connection->error_code = BAD_CP_FORMAT;
226                 return 1;
227             }
228             break;
229         case AVDTP_HEADER_COMPRESSION:
230             break;
231         case AVDTP_MULTIPLEXING:
232             break;
233         case AVDTP_MEDIA_CODEC:
234             break;
235         default:
236             break;
237     }
238     return 0;
239 }
240 
241 uint16_t avdtp_unpack_service_capabilities(avdtp_connection_t * connection, avdtp_capabilities_t * caps, uint8_t * packet, uint16_t size){
242     if (size == 0) return 0;
243 
244     uint16_t registered_service_categories = 0;
245     int pos = 0;
246     int i;
247     avdtp_service_category_t category = (avdtp_service_category_t)packet[pos++];
248     uint8_t cap_len = packet[pos++];
249 
250     if (avdtp_unpack_service_capabilities_has_errors(connection, category, cap_len)) return 0;
251     int processed_cap_len = 0;
252     int rfa = 0;
253     //printf(" size %d, cat size %d\n", size, cap_len);
254 
255     while (pos < size){
256         if (cap_len > size - pos){
257             connection->reject_service_category = category;
258             connection->error_code = BAD_LENGTH;
259             return 0;
260         }
261         rfa = 0;
262         processed_cap_len = pos;
263         switch(category){
264             case AVDTP_RECOVERY:
265                 caps->recovery.recovery_type = packet[pos++];
266                 caps->recovery.maximum_recovery_window_size = packet[pos++];
267                 caps->recovery.maximum_number_media_packets = packet[pos++];
268                 break;
269             case AVDTP_CONTENT_PROTECTION:
270                 caps->content_protection.cp_type = big_endian_read_16(packet, pos);
271                 pos+=2;
272 
273                 caps->content_protection.cp_type_value_len = cap_len - 2;
274                 pos += caps->content_protection.cp_type_value_len;
275 
276                 // connection->reject_service_category = category;
277                 // connection->error_code = UNSUPPORTED_CONFIGURATION;
278                 // support for content protection goes here
279                 break;
280 
281             case AVDTP_HEADER_COMPRESSION:
282                 caps->header_compression.back_ch  = packet[pos] >> 7;
283                 caps->header_compression.media    = packet[pos] >> 6;
284                 caps->header_compression.recovery = packet[pos] >> 5;
285                 pos++;
286                 break;
287             case AVDTP_MULTIPLEXING:
288                 caps->multiplexing_mode.fragmentation = packet[pos++] >> 7;
289                 // read [tsid, tcid] for media, reporting. recovery respectively
290                 caps->multiplexing_mode.transport_identifiers_num = 3;
291                 for (i=0; i<caps->multiplexing_mode.transport_identifiers_num; i++){
292                     caps->multiplexing_mode.transport_session_identifiers[i] = packet[pos++] >> 7;
293                     caps->multiplexing_mode.tcid[i] = packet[pos++] >> 7;
294                 }
295                 break;
296             case AVDTP_MEDIA_CODEC:
297                 caps->media_codec.media_type = packet[pos++] >> 4;
298                 caps->media_codec.media_codec_type = packet[pos++];
299                 caps->media_codec.media_codec_information_len = cap_len - 2;
300                 caps->media_codec.media_codec_information = &packet[pos];
301                 pos += caps->media_codec.media_codec_information_len;
302                 break;
303             case AVDTP_MEDIA_TRANSPORT:
304             case AVDTP_REPORTING:
305             case AVDTP_DELAY_REPORTING:
306                 pos += cap_len;
307                 break;
308             default:
309                 pos += cap_len;
310                 rfa = 1;
311                 break;
312         }
313         processed_cap_len = pos - processed_cap_len;
314 
315         if (cap_len == processed_cap_len){
316             if (!rfa) {
317                 registered_service_categories = store_bit16(registered_service_categories, category, 1);
318             }
319             if (pos < size-2){
320                 //int old_pos = pos;
321                 category = (avdtp_service_category_t)packet[pos++];
322                 cap_len = packet[pos++];
323                 if (avdtp_unpack_service_capabilities_has_errors(connection, category, cap_len)) return 0;
324                 //printf("category %d, pos %d + 2 + %d -> %d\n", category, old_pos, cap_len, pos + cap_len);
325                 //printf_hexdump(packet+old_pos, size-old_pos);
326             }
327         }
328     }
329     return registered_service_categories;
330 }
331 
332 void avdtp_prepare_capabilities(avdtp_signaling_packet_t * signaling_packet, uint8_t transaction_label, uint16_t registered_service_categories, avdtp_capabilities_t capabilities, uint8_t identifier){
333     if (signaling_packet->offset) return;
334     uint8_t pack_all_capabilities = 1;
335     signaling_packet->message_type = AVDTP_RESPONSE_ACCEPT_MSG;
336     signaling_packet->size = 0;
337     int i;
338     signaling_packet->command[signaling_packet->size++] = signaling_packet->acp_seid << 2;
339 
340     switch (identifier) {
341         case AVDTP_SI_GET_CAPABILITIES:
342             pack_all_capabilities = 0;
343             break;
344         case AVDTP_SI_GET_ALL_CAPABILITIES:
345             pack_all_capabilities = 1;
346             break;
347         case AVDTP_SI_SET_CONFIGURATION:
348             signaling_packet->command[signaling_packet->size++] = signaling_packet->int_seid << 2;
349             signaling_packet->message_type = AVDTP_CMD_MSG;
350             break;
351         case AVDTP_SI_RECONFIGURE:
352             signaling_packet->message_type = AVDTP_CMD_MSG;
353             break;
354         default:
355             log_error("avdtp_prepare_capabilities wrong identifier %d", identifier);
356             break;
357     }
358 
359     for (i = 1; i < 9; i++){
360         if (get_bit16(registered_service_categories, i)){
361             // service category
362             signaling_packet->command[signaling_packet->size++] = i;
363             signaling_packet->size += avdtp_pack_service_capabilities(signaling_packet->command+signaling_packet->size, sizeof(signaling_packet->command)-signaling_packet->size, capabilities, (avdtp_service_category_t)i, pack_all_capabilities);
364         }
365     }
366     // signaling_packet->command[signaling_packet->size++] = 0x04;
367     // signaling_packet->command[signaling_packet->size++] = 0x02;
368     // signaling_packet->command[signaling_packet->size++] = 0x02;
369     // signaling_packet->command[signaling_packet->size++] = 0x00;
370 
371     signaling_packet->signal_identifier = identifier;
372     signaling_packet->transaction_label = transaction_label;
373 }
374 
375 int avdtp_signaling_create_fragment(uint16_t cid, avdtp_signaling_packet_t * signaling_packet, uint8_t * out_buffer) {
376     int mtu = l2cap_get_remote_mtu_for_local_cid(cid);
377     // hack for test
378     // int mtu = 6;
379     int data_len = 0;
380 
381     uint16_t offset = signaling_packet->offset;
382     uint16_t pos = 1;
383     // printf(" avdtp_signaling_create_fragment offset %d, packet type %d\n",  signaling_packet->offset, signaling_packet->packet_type);
384 
385     if (offset == 0){
386         if (signaling_packet->size <= mtu - 2){
387             // printf(" AVDTP_SINGLE_PACKET\n");
388             signaling_packet->packet_type = AVDTP_SINGLE_PACKET;
389             out_buffer[pos++] = signaling_packet->signal_identifier;
390             data_len = signaling_packet->size;
391         } else {
392             signaling_packet->packet_type = AVDTP_START_PACKET;
393             out_buffer[pos++] = (mtu + signaling_packet->size)/ (mtu-1);
394             out_buffer[pos++] = signaling_packet->signal_identifier;
395             data_len = mtu - 3;
396             signaling_packet->offset = data_len;
397             // printf(" AVDTP_START_PACKET len %d, offset %d\n", signaling_packet->size, signaling_packet->offset);
398         }
399     } else {
400         int remaining_bytes = signaling_packet->size - offset;
401         if (remaining_bytes <= mtu - 1){
402             //signaling_packet->fragmentation = 1;
403             signaling_packet->packet_type = AVDTP_END_PACKET;
404             data_len = remaining_bytes;
405             signaling_packet->offset = 0;
406             // printf(" AVDTP_END_PACKET len %d, offset %d\n", signaling_packet->size, signaling_packet->offset);
407         } else{
408             signaling_packet->packet_type = AVDTP_CONTINUE_PACKET;
409             data_len = mtu - 1;
410             signaling_packet->offset += data_len;
411             // printf(" AVDTP_CONTINUE_PACKET len %d, offset %d\n", signaling_packet->size, signaling_packet->offset);
412         }
413     }
414     out_buffer[0] = avdtp_header(signaling_packet->transaction_label, signaling_packet->packet_type, signaling_packet->message_type);
415     memcpy(out_buffer+pos, signaling_packet->command + offset, data_len);
416     pos += data_len;
417     return pos;
418 }
419 
420 
421 void avdtp_signaling_emit_connection_established(btstack_packet_handler_t callback, uint16_t con_handle, bd_addr_t addr, uint8_t status){
422     if (!callback) return;
423     uint8_t event[12];
424     int pos = 0;
425     event[pos++] = HCI_EVENT_AVDTP_META;
426     event[pos++] = sizeof(event) - 2;
427     event[pos++] = AVDTP_SUBEVENT_SIGNALING_CONNECTION_ESTABLISHED;
428     little_endian_store_16(event, pos, con_handle);
429     pos += 2;
430     reverse_bd_addr(addr,&event[pos]);
431     pos += 6;
432     event[pos++] = status;
433     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
434 }
435 
436 void avdtp_signaling_emit_sep(btstack_packet_handler_t callback, uint16_t con_handle, avdtp_sep_t sep){
437     if (!callback) return;
438     uint8_t event[9];
439     int pos = 0;
440     event[pos++] = HCI_EVENT_AVDTP_META;
441     event[pos++] = sizeof(event) - 2;
442     event[pos++] = AVDTP_SUBEVENT_SIGNALING_SEP_FOUND;
443     little_endian_store_16(event, pos, con_handle);
444     pos += 2;
445     event[pos++] = sep.seid;
446     event[pos++] = sep.in_use;
447     event[pos++] = sep.media_type;
448     event[pos++] = sep.type;
449     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
450 }
451 
452 void avdtp_signaling_emit_accept(btstack_packet_handler_t callback, uint16_t con_handle, avdtp_signal_identifier_t identifier, uint8_t status){
453     if (!callback) return;
454     uint8_t event[7];
455     int pos = 0;
456     event[pos++] = HCI_EVENT_AVDTP_META;
457     event[pos++] = sizeof(event) - 2;
458     event[pos++] = AVDTP_SUBEVENT_SIGNALING_ACCEPT;
459     little_endian_store_16(event, pos, con_handle);
460     pos += 2;
461     event[pos++] = identifier;
462     event[pos++] = status;
463     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
464 }
465 
466 void avdtp_signaling_emit_reject(btstack_packet_handler_t callback, uint16_t con_handle, avdtp_signal_identifier_t identifier){
467     if (!callback) return;
468     uint8_t event[6];
469     int pos = 0;
470     event[pos++] = HCI_EVENT_AVDTP_META;
471     event[pos++] = sizeof(event) - 2;
472     event[pos++] = AVDTP_SUBEVENT_SIGNALING_REJECT;
473     little_endian_store_16(event, pos, con_handle);
474     pos += 2;
475     event[pos++] = identifier;
476     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
477 }
478 
479 void avdtp_signaling_emit_general_reject(btstack_packet_handler_t callback, uint16_t con_handle, avdtp_signal_identifier_t identifier){
480     if (!callback) return;
481     uint8_t event[6];
482     int pos = 0;
483     event[pos++] = HCI_EVENT_AVDTP_META;
484     event[pos++] = sizeof(event) - 2;
485     event[pos++] = AVDTP_SUBEVENT_SIGNALING_GENERAL_REJECT;
486     little_endian_store_16(event, pos, con_handle);
487     pos += 2;
488     event[pos++] = identifier;
489     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
490 }
491 
492 void avdtp_signaling_emit_media_codec_sbc_capability(btstack_packet_handler_t callback, uint16_t con_handle, adtvp_media_codec_capabilities_t media_codec){
493     if (!callback) return;
494     uint8_t event[13];
495     int pos = 0;
496     event[pos++] = HCI_EVENT_AVDTP_META;
497     event[pos++] = sizeof(event) - 2;
498     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CAPABILITY;
499     little_endian_store_16(event, pos, con_handle);
500     pos += 2;
501     event[pos++] = media_codec.media_type;
502     event[pos++] = media_codec.media_codec_information[0] >> 4;
503     event[pos++] = media_codec.media_codec_information[0] & 0x0F;
504     event[pos++] = media_codec.media_codec_information[1] >> 4;
505     event[pos++] = (media_codec.media_codec_information[1] & 0x0F) >> 2;
506     event[pos++] = media_codec.media_codec_information[1] & 0x03;
507     event[pos++] = media_codec.media_codec_information[2];
508     event[pos++] = media_codec.media_codec_information[3];
509     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
510 }
511 
512 void avdtp_signaling_emit_media_codec_other_capability(btstack_packet_handler_t callback, uint16_t con_handle, adtvp_media_codec_capabilities_t media_codec){
513     if (!callback) return;
514         uint8_t event[109];
515     int pos = 0;
516     event[pos++] = HCI_EVENT_AVDTP_META;
517     event[pos++] = sizeof(event) - 2;
518     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CAPABILITY;
519     little_endian_store_16(event, pos, con_handle);
520     pos += 2;
521     event[pos++] = media_codec.media_type;
522     little_endian_store_16(event, pos, media_codec.media_codec_type);
523     pos += 2;
524     little_endian_store_16(event, pos, media_codec.media_codec_information_len);
525     pos += 2;
526     if (media_codec.media_codec_information_len < 100){
527         memcpy(event+pos, media_codec.media_codec_information, media_codec.media_codec_information_len);
528     } else {
529         memcpy(event+pos, media_codec.media_codec_information, 100);
530     }
531     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
532 }
533 
534 static inline void avdtp_signaling_emit_media_codec_sbc(btstack_packet_handler_t callback, uint16_t con_handle, adtvp_media_codec_capabilities_t media_codec, uint8_t reconfigure){
535     if (!callback) return;
536     uint8_t event[14+2];
537     int pos = 0;
538     event[pos++] = HCI_EVENT_AVDTP_META;
539     event[pos++] = sizeof(event) - 2;
540 
541     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CONFIGURATION;
542     little_endian_store_16(event, pos, con_handle);
543     pos += 2;
544     event[pos++] = reconfigure;
545 
546     uint8_t num_channels = 0;
547     uint16_t sampling_frequency = 0;
548     uint8_t subbands = 0;
549     uint8_t block_length = 0;
550 
551     uint8_t sampling_frequency_bitmap = media_codec.media_codec_information[0] >> 4;
552     uint8_t channel_mode_bitmap = media_codec.media_codec_information[0] & 0x0F;
553     uint8_t block_length_bitmap = media_codec.media_codec_information[1] >> 4;
554     uint8_t subbands_bitmap = (media_codec.media_codec_information[1] & 0x0F) >> 2;
555 
556     if (channel_mode_bitmap & AVDTP_SBC_MONO){
557         num_channels = 1;
558     }
559     if ( (channel_mode_bitmap & AVDTP_SBC_JOINT_STEREO) ||
560          (channel_mode_bitmap & AVDTP_SBC_STEREO) ||
561          (channel_mode_bitmap & AVDTP_SBC_DUAL_CHANNEL) ){
562         num_channels = 2;
563     }
564 
565     if (sampling_frequency_bitmap & AVDTP_SBC_16000){
566         sampling_frequency = 16000;
567     }
568     if (sampling_frequency_bitmap & AVDTP_SBC_32000){
569         sampling_frequency = 32000;
570     }
571     if (sampling_frequency_bitmap & AVDTP_SBC_44100){
572         sampling_frequency = 44100;
573     }
574     if (sampling_frequency_bitmap & AVDTP_SBC_48000){
575         sampling_frequency = 48000;
576     }
577 
578     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_4){
579         subbands = 4;
580     }
581     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_8){
582         subbands = 8;
583     }
584 
585     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_4){
586         block_length = 4;
587     }
588     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_8){
589         block_length = 8;
590     }
591     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_12){
592         block_length = 12;
593     }
594     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_16){
595         block_length = 16;
596     }
597 
598     event[pos++] = media_codec.media_type;
599     little_endian_store_16(event, pos, sampling_frequency);
600     pos += 2;
601 
602     event[pos++] = channel_mode_bitmap;
603     event[pos++] = num_channels;
604     event[pos++] = block_length;
605     event[pos++] = subbands;
606     event[pos++] = media_codec.media_codec_information[1] & 0x03;
607     event[pos++] = media_codec.media_codec_information[2];
608     event[pos++] = media_codec.media_codec_information[3];
609     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
610 }
611 
612 void avdtp_signaling_emit_media_codec_sbc_configuration(btstack_packet_handler_t callback, uint16_t con_handle, adtvp_media_codec_capabilities_t media_codec){
613     if (!callback) return;
614     avdtp_signaling_emit_media_codec_sbc(callback, con_handle, media_codec, 0);
615 }
616 
617 void avdtp_signaling_emit_media_codec_sbc_reconfiguration(btstack_packet_handler_t callback, uint16_t con_handle, adtvp_media_codec_capabilities_t media_codec){
618     if (!callback) return;
619     avdtp_signaling_emit_media_codec_sbc(callback, con_handle, media_codec, 1);
620 }
621 
622 static inline void avdtp_signaling_emit_media_codec_other(btstack_packet_handler_t callback, uint16_t con_handle, adtvp_media_codec_capabilities_t media_codec, uint8_t reconfigure){
623     uint8_t event[110];
624     int pos = 0;
625     event[pos++] = HCI_EVENT_AVDTP_META;
626     event[pos++] = sizeof(event) - 2;
627     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CONFIGURATION;
628     little_endian_store_16(event, pos, con_handle);
629     pos += 2;
630 
631     event[pos++] = reconfigure;
632 
633     event[pos++] = media_codec.media_type;
634     little_endian_store_16(event, pos, media_codec.media_codec_type);
635     pos += 2;
636     little_endian_store_16(event, pos, media_codec.media_codec_information_len);
637     pos += 2;
638 
639     if (media_codec.media_codec_information_len < 100){
640         memcpy(event+pos, media_codec.media_codec_information, media_codec.media_codec_information_len);
641     } else {
642         memcpy(event+pos, media_codec.media_codec_information, 100);
643     }
644     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
645 }
646 
647 void avdtp_signaling_emit_media_codec_other_configuration(btstack_packet_handler_t callback, uint16_t con_handle, adtvp_media_codec_capabilities_t media_codec){
648     if (!callback) return;
649     avdtp_signaling_emit_media_codec_other(callback, con_handle, media_codec, 0);
650 }
651 
652 void avdtp_signaling_emit_media_codec_other_reconfiguration(btstack_packet_handler_t callback, uint16_t con_handle, adtvp_media_codec_capabilities_t media_codec){
653     if (!callback) return;
654     avdtp_signaling_emit_media_codec_other(callback, con_handle, media_codec, 1);
655 }
656 
657 
658 void avdtp_sink_request_can_send_now_acceptor(avdtp_connection_t * connection, uint16_t l2cap_cid){
659     connection->wait_to_send_acceptor = 1;
660     l2cap_request_can_send_now_event(l2cap_cid);
661 }
662 void avdtp_sink_request_can_send_now_initiator(avdtp_connection_t * connection, uint16_t l2cap_cid){
663     connection->wait_to_send_initiator = 1;
664     l2cap_request_can_send_now_event(l2cap_cid);
665 }
666 void avdtp_sink_request_can_send_now_self(avdtp_connection_t * connection, uint16_t l2cap_cid){
667     connection->wait_to_send_self = 1;
668     l2cap_request_can_send_now_event(l2cap_cid);
669 }
670 
671 avdtp_stream_endpoint_t * get_avdtp_stream_endpoint_for_seid(uint16_t seid){
672     btstack_linked_list_iterator_t it;
673     btstack_linked_list_iterator_init(&it, (btstack_linked_list_t *) &stream_endpoints);
674     while (btstack_linked_list_iterator_has_next(&it)){
675         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
676         if (stream_endpoint->sep.seid == seid){
677             return stream_endpoint;
678         }
679     }
680     return NULL;
681 }
682 
683 uint8_t avdtp_get_index_of_remote_stream_endpoint_with_seid(avdtp_stream_endpoint_t * stream_endpoint, uint16_t seid){
684     if (stream_endpoint->remote_seps[stream_endpoint->remote_sep_index].seid == seid){
685         return stream_endpoint->remote_sep_index;
686     }
687     int i;
688     for (i=0; i < stream_endpoint->remote_seps_num; i++){
689         if (stream_endpoint->remote_seps[i].seid == seid){
690             return i;
691         }
692     }
693     return 0xFF;
694 }
695