xref: /btstack/src/classic/avdtp_util.c (revision 58c560219426df86e08670b9ca7d3d1f9979a6c1)
1 /*
2  * Copyright (C) 2016 BlueKitchen GmbH
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the copyright holders nor the names of
14  *    contributors may be used to endorse or promote products derived
15  *    from this software without specific prior written permission.
16  * 4. Any redistribution, use, or modification is done solely for
17  *    personal benefit and not for any commercial purpose or for
18  *    monetary gain.
19  *
20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
24  * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
30  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * Please inquire about commercial licensing options at
34  * [email protected]
35  *
36  */
37 
38 #define __BTSTACK_FILE__ "avdtp_util.c"
39 
40 
41 #include <stdint.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 
46 #include "btstack.h"
47 #include "avdtp.h"
48 #include "avdtp_util.h"
49 
50 inline uint8_t avdtp_header(uint8_t tr_label, avdtp_packet_type_t packet_type, avdtp_message_type_t msg_type){
51     return (tr_label<<4) | ((uint8_t)packet_type<<2) | (uint8_t)msg_type;
52 }
53 
54 void avdtp_initialize_stream_endpoint(avdtp_stream_endpoint_t * stream_endpoint){
55     stream_endpoint->connection = NULL;
56     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_IDLE;
57     stream_endpoint->acceptor_config_state = AVDTP_ACCEPTOR_STREAM_CONFIG_IDLE;
58     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_STREAM_CONFIG_IDLE;
59     stream_endpoint->remote_sep_index = AVDTP_INVALID_SEP_INDEX;
60     stream_endpoint->media_disconnect = 0;
61     stream_endpoint->sep.in_use = 0;
62     stream_endpoint->remote_sep_index = 0;
63 }
64 
65 avdtp_stream_endpoint_t * avdtp_stream_endpoint_for_seid(uint16_t seid, avdtp_context_t * context){
66     btstack_linked_list_iterator_t it;
67     btstack_linked_list_iterator_init(&it, &context->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->sep.seid == seid){
71             return stream_endpoint;
72         }
73     }
74     return NULL;
75 }
76 
77 avdtp_connection_t * avdtp_connection_for_bd_addr(bd_addr_t addr, avdtp_context_t * context){
78     btstack_linked_list_iterator_t it;
79     btstack_linked_list_iterator_init(&it, &context->connections);
80     while (btstack_linked_list_iterator_has_next(&it)){
81         avdtp_connection_t * connection = (avdtp_connection_t *)btstack_linked_list_iterator_next(&it);
82         if (memcmp(addr, connection->remote_addr, 6) != 0) continue;
83         return connection;
84     }
85     return NULL;
86 }
87 
88 avdtp_connection_t * avdtp_connection_for_l2cap_signaling_cid(uint16_t l2cap_cid, avdtp_context_t * context){
89     btstack_linked_list_iterator_t it;
90     btstack_linked_list_iterator_init(&it, &context->connections);
91     while (btstack_linked_list_iterator_has_next(&it)){
92         avdtp_connection_t * connection = (avdtp_connection_t *)btstack_linked_list_iterator_next(&it);
93         if (connection->l2cap_signaling_cid != l2cap_cid) continue;
94         return connection;
95     }
96     return NULL;
97 }
98 
99 avdtp_stream_endpoint_t * avdtp_stream_endpoint_for_l2cap_cid(uint16_t l2cap_cid, avdtp_context_t * context){
100     btstack_linked_list_iterator_t it;
101     btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
102     while (btstack_linked_list_iterator_has_next(&it)){
103         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
104         if (stream_endpoint->l2cap_media_cid == l2cap_cid){
105             return stream_endpoint;
106         }
107         if (stream_endpoint->l2cap_reporting_cid == l2cap_cid){
108             return stream_endpoint;
109         }
110         if (stream_endpoint->l2cap_recovery_cid == l2cap_cid){
111             return stream_endpoint;
112         }
113     }
114     return NULL;
115 }
116 
117 avdtp_stream_endpoint_t * avdtp_stream_endpoint_with_seid(uint8_t seid, avdtp_context_t * context){
118     btstack_linked_list_iterator_t it;
119     btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
120     while (btstack_linked_list_iterator_has_next(&it)){
121         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
122         if (stream_endpoint->sep.seid == seid){
123             return stream_endpoint;
124         }
125     }
126     return NULL;
127 }
128 
129 avdtp_stream_endpoint_t * avdtp_stream_endpoint_associated_with_acp_seid(uint16_t acp_seid, avdtp_context_t * context){
130     btstack_linked_list_iterator_t it;
131     btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
132     while (btstack_linked_list_iterator_has_next(&it)){
133         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
134 
135         if (stream_endpoint->remote_sep_index != AVDTP_INVALID_SEP_INDEX){
136             if (!stream_endpoint->connection) continue;
137             if (stream_endpoint->connection->remote_seps[stream_endpoint->remote_sep_index].seid == acp_seid){
138                 return stream_endpoint;
139             }
140         }
141     }
142     return NULL;
143 }
144 
145 int get_bit16(uint16_t bitmap, int position){
146     return (bitmap >> position) & 1;
147 }
148 
149 uint8_t store_bit16(uint16_t bitmap, int position, uint8_t value){
150     if (value){
151         bitmap |= 1 << position;
152     } else {
153         bitmap &= ~ (1 << position);
154     }
155     return bitmap;
156 }
157 
158 int avdtp_read_signaling_header(avdtp_signaling_packet_t * signaling_header, uint8_t * packet, uint16_t size){
159     int pos = 0;
160     if (size < 2) return pos;
161     signaling_header->transaction_label = packet[pos] >> 4;
162     signaling_header->packet_type = (avdtp_packet_type_t)((packet[pos] >> 2) & 0x03);
163     signaling_header->message_type = (avdtp_message_type_t) (packet[pos] & 0x03);
164     pos++;
165     memset(signaling_header->command, 0, sizeof(signaling_header->command));
166     switch (signaling_header->packet_type){
167         case AVDTP_SINGLE_PACKET:
168             signaling_header->num_packets = 0;
169             signaling_header->offset = 0;
170             signaling_header->size = 0;
171             break;
172         case AVDTP_END_PACKET:
173             signaling_header->num_packets = 0;
174             break;
175         case AVDTP_START_PACKET:
176             signaling_header->num_packets = packet[pos++];
177             signaling_header->size = 0;
178             signaling_header->offset = 0;
179             break;
180         case AVDTP_CONTINUE_PACKET:
181             if (signaling_header->num_packets <= 0) {
182                 log_info("    ERROR: wrong num fragmented packets\n");
183                 break;
184             }
185             signaling_header->num_packets--;
186             break;
187     }
188     signaling_header->signal_identifier = (avdtp_signal_identifier_t)(packet[pos++] & 0x3f);
189     return pos;
190 }
191 
192 int avdtp_pack_service_capabilities(uint8_t * buffer, int size, avdtp_capabilities_t caps, avdtp_service_category_t category, uint8_t pack_all_capabilities){
193     UNUSED(size);
194 
195     int i;
196     // pos = 0 reserved for length
197     int pos = 1;
198     switch(category){
199         case AVDTP_MEDIA_TRANSPORT:
200         case AVDTP_REPORTING:
201             break;
202         case AVDTP_DELAY_REPORTING:
203             if (!pack_all_capabilities) break;
204             break;
205         case AVDTP_RECOVERY:
206             buffer[pos++] = caps.recovery.recovery_type; // 0x01=RFC2733
207             buffer[pos++] = caps.recovery.maximum_recovery_window_size;
208             buffer[pos++] = caps.recovery.maximum_number_media_packets;
209             break;
210         case AVDTP_CONTENT_PROTECTION:
211             buffer[pos++] = caps.content_protection.cp_type_value_len + 2;
212             big_endian_store_16(buffer, pos, caps.content_protection.cp_type);
213             pos += 2;
214             memcpy(buffer+pos, caps.content_protection.cp_type_value, caps.content_protection.cp_type_value_len);
215             break;
216         case AVDTP_HEADER_COMPRESSION:
217             buffer[pos++] = (caps.header_compression.back_ch << 7) | (caps.header_compression.media << 6) | (caps.header_compression.recovery << 5);
218             break;
219         case AVDTP_MULTIPLEXING:
220             buffer[pos++] = caps.multiplexing_mode.fragmentation << 7;
221             for (i=0; i<caps.multiplexing_mode.transport_identifiers_num; i++){
222                 buffer[pos++] = caps.multiplexing_mode.transport_session_identifiers[i] << 7;
223                 buffer[pos++] = caps.multiplexing_mode.tcid[i] << 7;
224                 // media, reporting. recovery
225             }
226             break;
227         case AVDTP_MEDIA_CODEC:
228             buffer[pos++] = ((uint8_t)caps.media_codec.media_type) << 4;
229             buffer[pos++] = (uint8_t)caps.media_codec.media_codec_type;
230             for (i = 0; i<caps.media_codec.media_codec_information_len; i++){
231                 buffer[pos++] = caps.media_codec.media_codec_information[i];
232             }
233             break;
234         default:
235             break;
236     }
237     buffer[0] = pos - 1; // length
238     return pos;
239 }
240 
241 static int avdtp_unpack_service_capabilities_has_errors(avdtp_connection_t * connection, avdtp_service_category_t category, uint8_t cap_len){
242     connection->error_code = 0;
243 
244     if (category == AVDTP_SERVICE_CATEGORY_INVALID_0 ||
245         (category == AVDTP_SERVICE_CATEGORY_INVALID_FF && connection->signaling_packet.signal_identifier == AVDTP_SI_RECONFIGURE)){
246         log_info("    ERROR: BAD SERVICE CATEGORY %d\n", category);
247         connection->reject_service_category = category;
248         connection->error_code = BAD_SERV_CATEGORY;
249         return 1;
250     }
251 
252     if (connection->signaling_packet.signal_identifier == AVDTP_SI_RECONFIGURE){
253         if (category != AVDTP_CONTENT_PROTECTION && category != AVDTP_MEDIA_CODEC){
254             log_info("    ERROR: REJECT CATEGORY, INVALID_CAPABILITIES\n");
255             connection->reject_service_category = category;
256             connection->error_code = INVALID_CAPABILITIES;
257             return 1;
258         }
259     }
260 
261     switch(category){
262         case AVDTP_MEDIA_TRANSPORT:
263             if (cap_len != 0){
264                 log_info("    ERROR: REJECT CATEGORY, BAD_MEDIA_TRANSPORT\n");
265                 connection->reject_service_category = category;
266                 connection->error_code = BAD_MEDIA_TRANSPORT_FORMAT;
267                 return 1;
268             }
269             break;
270         case AVDTP_REPORTING:
271         case AVDTP_DELAY_REPORTING:
272             if (cap_len != 0){
273                 log_info("    ERROR: REJECT CATEGORY, BAD_LENGTH\n");
274                 connection->reject_service_category = category;
275                 connection->error_code = BAD_LENGTH;
276                 return 1;
277             }
278             break;
279         case AVDTP_RECOVERY:
280             if (cap_len < 3){
281                 log_info("    ERROR: REJECT CATEGORY, BAD_MEDIA_TRANSPORT\n");
282                 connection->reject_service_category = category;
283                 connection->error_code = BAD_RECOVERY_FORMAT;
284                 return 1;
285             }
286             break;
287         case AVDTP_CONTENT_PROTECTION:
288             if (cap_len < 2){
289                 log_info("    ERROR: REJECT CATEGORY, BAD_CP_FORMAT\n");
290                 connection->reject_service_category = category;
291                 connection->error_code = BAD_CP_FORMAT;
292                 return 1;
293             }
294             break;
295         case AVDTP_HEADER_COMPRESSION:
296             break;
297         case AVDTP_MULTIPLEXING:
298             break;
299         case AVDTP_MEDIA_CODEC:
300             break;
301         default:
302             break;
303     }
304     return 0;
305 }
306 
307 uint16_t avdtp_unpack_service_capabilities(avdtp_connection_t * connection, avdtp_capabilities_t * caps, uint8_t * packet, uint16_t size){
308     if (size == 0) return 0;
309 
310     uint16_t registered_service_categories = 0;
311     int pos = 0;
312     int i;
313     avdtp_service_category_t category = (avdtp_service_category_t)packet[pos++];
314     uint8_t cap_len = packet[pos++];
315 
316     if (avdtp_unpack_service_capabilities_has_errors(connection, category, cap_len)) return 0;
317     int processed_cap_len = 0;
318     int rfa = 0;
319 
320     while (pos < size){
321         if (cap_len > size - pos){
322             connection->reject_service_category = category;
323             connection->error_code = BAD_LENGTH;
324             return 0;
325         }
326         rfa = 0;
327         processed_cap_len = pos;
328         switch(category){
329             case AVDTP_RECOVERY:
330                 caps->recovery.recovery_type = packet[pos++];
331                 caps->recovery.maximum_recovery_window_size = packet[pos++];
332                 caps->recovery.maximum_number_media_packets = packet[pos++];
333                 break;
334             case AVDTP_CONTENT_PROTECTION:
335                 caps->content_protection.cp_type = big_endian_read_16(packet, pos);
336                 pos+=2;
337 
338                 caps->content_protection.cp_type_value_len = cap_len - 2;
339                 pos += caps->content_protection.cp_type_value_len;
340 
341                 // connection->reject_service_category = category;
342                 // connection->error_code = UNSUPPORTED_CONFIGURATION;
343                 // support for content protection goes here
344                 break;
345 
346             case AVDTP_HEADER_COMPRESSION:
347                 caps->header_compression.back_ch  = packet[pos] >> 7;
348                 caps->header_compression.media    = packet[pos] >> 6;
349                 caps->header_compression.recovery = packet[pos] >> 5;
350                 pos++;
351                 break;
352             case AVDTP_MULTIPLEXING:
353                 caps->multiplexing_mode.fragmentation = packet[pos++] >> 7;
354                 // read [tsid, tcid] for media, reporting. recovery respectively
355                 caps->multiplexing_mode.transport_identifiers_num = 3;
356                 for (i=0; i<caps->multiplexing_mode.transport_identifiers_num; i++){
357                     caps->multiplexing_mode.transport_session_identifiers[i] = packet[pos++] >> 7;
358                     caps->multiplexing_mode.tcid[i] = packet[pos++] >> 7;
359                 }
360                 break;
361             case AVDTP_MEDIA_CODEC:
362                 caps->media_codec.media_type = (avdtp_media_type_t)(packet[pos++] >> 4);
363                 caps->media_codec.media_codec_type = (avdtp_media_codec_type_t)(packet[pos++]);
364                 caps->media_codec.media_codec_information_len = cap_len - 2;
365                 caps->media_codec.media_codec_information = &packet[pos];
366                 pos += caps->media_codec.media_codec_information_len;
367                 break;
368             case AVDTP_MEDIA_TRANSPORT:
369             case AVDTP_REPORTING:
370             case AVDTP_DELAY_REPORTING:
371                 pos += cap_len;
372                 break;
373             default:
374                 pos += cap_len;
375                 rfa = 1;
376                 break;
377         }
378         processed_cap_len = pos - processed_cap_len;
379 
380         if (cap_len == processed_cap_len){
381             if (!rfa) {
382                 registered_service_categories = store_bit16(registered_service_categories, category, 1);
383             }
384             if (pos < size-2){
385                 //int old_pos = pos;
386                 category = (avdtp_service_category_t)packet[pos++];
387                 cap_len = packet[pos++];
388                 if (avdtp_unpack_service_capabilities_has_errors(connection, category, cap_len)) return 0;
389             }
390         }
391     }
392     return registered_service_categories;
393 }
394 
395 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){
396     if (signaling_packet->offset) return;
397     uint8_t pack_all_capabilities = 1;
398     signaling_packet->message_type = AVDTP_RESPONSE_ACCEPT_MSG;
399     int i;
400 
401     signaling_packet->size = 0;
402     memset(signaling_packet->command, 0 , sizeof(signaling_packet->command));
403 
404 
405     switch (identifier) {
406         case AVDTP_SI_GET_CAPABILITIES:
407             pack_all_capabilities = 0;
408             break;
409         case AVDTP_SI_GET_ALL_CAPABILITIES:
410             pack_all_capabilities = 1;
411             break;
412         case AVDTP_SI_SET_CONFIGURATION:
413             signaling_packet->command[signaling_packet->size++] = signaling_packet->acp_seid << 2;
414             signaling_packet->command[signaling_packet->size++] = signaling_packet->int_seid << 2;
415             signaling_packet->message_type = AVDTP_CMD_MSG;
416             break;
417         case AVDTP_SI_RECONFIGURE:
418             signaling_packet->command[signaling_packet->size++] = signaling_packet->acp_seid << 2;
419             signaling_packet->message_type = AVDTP_CMD_MSG;
420             break;
421         default:
422             log_error("avdtp_prepare_capabilities wrong identifier %d", identifier);
423             break;
424     }
425 
426     for (i = 1; i < 9; i++){
427         int registered_category = get_bit16(registered_service_categories, i);
428         if (!registered_category && (identifier == AVDTP_SI_SET_CONFIGURATION || identifier == AVDTP_SI_RECONFIGURE)){
429             // TODO: introduce bitmap of mandatory categories
430             if (i == 1){
431                 registered_category = 1;
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, sizeof(signaling_packet->command)-signaling_packet->size, capabilities, (avdtp_service_category_t)i, pack_all_capabilities);
438         }
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     memcpy(out_buffer+pos, signaling_packet->command + offset, data_len);
478     pos += data_len;
479     return pos;
480 }
481 
482 
483 void avdtp_signaling_emit_connection_established(btstack_packet_handler_t callback, uint16_t avdtp_cid, bd_addr_t addr, uint8_t status){
484     if (!callback) return;
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     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
496 }
497 
498 void avdtp_streaming_emit_can_send_media_packet_now(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t seid, uint16_t sequence_number){
499     if (!callback) return;
500     uint8_t event[8];
501     int pos = 0;
502     event[pos++] = HCI_EVENT_AVDTP_META;
503     event[pos++] = sizeof(event) - 2;
504     event[pos++] = AVDTP_SUBEVENT_STREAMING_CAN_SEND_MEDIA_PACKET_NOW;
505     little_endian_store_16(event, pos, avdtp_cid);
506     pos += 2;
507     event[pos++] = seid;
508     little_endian_store_16(event, pos, sequence_number);
509     pos += 2;
510     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
511 }
512 
513 void avdtp_streaming_emit_connection_established(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, uint8_t status){
514     if (!callback) return;
515     uint8_t event[8];
516     int pos = 0;
517     event[pos++] = HCI_EVENT_AVDTP_META;
518     event[pos++] = sizeof(event) - 2;
519     event[pos++] = AVDTP_SUBEVENT_STREAMING_CONNECTION_ESTABLISHED;
520     little_endian_store_16(event, pos, avdtp_cid);
521     pos += 2;
522     event[pos++] = int_seid;
523     event[pos++] = acp_seid;
524     event[pos++] = status;
525     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
526 }
527 
528 void avdtp_signaling_emit_sep(btstack_packet_handler_t callback, uint16_t avdtp_cid, avdtp_sep_t sep){
529     if (!callback) return;
530     uint8_t event[9];
531     int pos = 0;
532     event[pos++] = HCI_EVENT_AVDTP_META;
533     event[pos++] = sizeof(event) - 2;
534     event[pos++] = AVDTP_SUBEVENT_SIGNALING_SEP_FOUND;
535     little_endian_store_16(event, pos, avdtp_cid);
536     pos += 2;
537     event[pos++] = sep.seid;
538     event[pos++] = sep.in_use;
539     event[pos++] = sep.media_type;
540     event[pos++] = sep.type;
541     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
542 }
543 
544 void avdtp_signaling_emit_accept(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, avdtp_signal_identifier_t identifier, uint8_t status){
545     if (!callback) return;
546     uint8_t event[8];
547     int pos = 0;
548     event[pos++] = HCI_EVENT_AVDTP_META;
549     event[pos++] = sizeof(event) - 2;
550     event[pos++] = AVDTP_SUBEVENT_SIGNALING_ACCEPT;
551     little_endian_store_16(event, pos, avdtp_cid);
552     pos += 2;
553     event[pos++] = int_seid;
554     event[pos++] = identifier;
555     event[pos++] = status;
556     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
557 }
558 
559 void avdtp_signaling_emit_reject(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, avdtp_signal_identifier_t identifier){
560     if (!callback) return;
561     uint8_t event[7];
562     int pos = 0;
563     event[pos++] = HCI_EVENT_AVDTP_META;
564     event[pos++] = sizeof(event) - 2;
565     event[pos++] = AVDTP_SUBEVENT_SIGNALING_REJECT;
566     little_endian_store_16(event, pos, avdtp_cid);
567     pos += 2;
568     event[pos++] = int_seid;
569     event[pos++] = identifier;
570     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
571 }
572 
573 void avdtp_signaling_emit_general_reject(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, avdtp_signal_identifier_t identifier){
574     if (!callback) return;
575     uint8_t event[7];
576     int pos = 0;
577     event[pos++] = HCI_EVENT_AVDTP_META;
578     event[pos++] = sizeof(event) - 2;
579     event[pos++] = AVDTP_SUBEVENT_SIGNALING_GENERAL_REJECT;
580     little_endian_store_16(event, pos, avdtp_cid);
581     pos += 2;
582     event[pos++] = int_seid;
583     event[pos++] = identifier;
584     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
585 }
586 
587 void avdtp_signaling_emit_media_codec_sbc_capability(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, adtvp_media_codec_capabilities_t media_codec){
588     if (!callback) return;
589     uint8_t event[15];
590     int pos = 0;
591     event[pos++] = HCI_EVENT_AVDTP_META;
592     event[pos++] = sizeof(event) - 2;
593     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CAPABILITY;
594     little_endian_store_16(event, pos, avdtp_cid);
595     pos += 2;
596     event[pos++] = int_seid;
597     event[pos++] = acp_seid;
598     event[pos++] = media_codec.media_type;
599     event[pos++] = media_codec.media_codec_information[0] >> 4;
600     event[pos++] = media_codec.media_codec_information[0] & 0x0F;
601     event[pos++] = media_codec.media_codec_information[1] >> 4;
602     event[pos++] = (media_codec.media_codec_information[1] & 0x0F) >> 2;
603     event[pos++] = media_codec.media_codec_information[1] & 0x03;
604     event[pos++] = media_codec.media_codec_information[2];
605     event[pos++] = media_codec.media_codec_information[3];
606     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
607 }
608 
609 void avdtp_signaling_emit_media_codec_other_capability(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, adtvp_media_codec_capabilities_t media_codec){
610     if (!callback) return;
611         uint8_t event[111];
612     int pos = 0;
613     event[pos++] = HCI_EVENT_AVDTP_META;
614     event[pos++] = sizeof(event) - 2;
615     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CAPABILITY;
616     little_endian_store_16(event, pos, avdtp_cid);
617     pos += 2;
618     event[pos++] = int_seid;
619     event[pos++] = acp_seid;
620     event[pos++] = media_codec.media_type;
621     little_endian_store_16(event, pos, media_codec.media_codec_type);
622     pos += 2;
623     little_endian_store_16(event, pos, media_codec.media_codec_information_len);
624     pos += 2;
625     if (media_codec.media_codec_information_len < 100){
626         memcpy(event+pos, media_codec.media_codec_information, media_codec.media_codec_information_len);
627     } else {
628         memcpy(event+pos, media_codec.media_codec_information, 100);
629     }
630     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
631 }
632 
633 static inline void avdtp_signaling_emit_media_codec_sbc(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, adtvp_media_codec_capabilities_t media_codec, uint8_t reconfigure){
634     if (!callback) return;
635     uint8_t event[16+2];
636     int pos = 0;
637     event[pos++] = HCI_EVENT_AVDTP_META;
638     event[pos++] = sizeof(event) - 2;
639 
640     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CONFIGURATION;
641     little_endian_store_16(event, pos, avdtp_cid);
642     pos += 2;
643     event[pos++] = int_seid;
644     event[pos++] = acp_seid;
645     event[pos++] = reconfigure;
646 
647     uint8_t num_channels = 0;
648     uint16_t sampling_frequency = 0;
649     uint8_t subbands = 0;
650     uint8_t block_length = 0;
651 
652     uint8_t sampling_frequency_bitmap = media_codec.media_codec_information[0] >> 4;
653     uint8_t channel_mode_bitmap = media_codec.media_codec_information[0] & 0x0F;
654     uint8_t block_length_bitmap = media_codec.media_codec_information[1] >> 4;
655     uint8_t subbands_bitmap = (media_codec.media_codec_information[1] & 0x0F) >> 2;
656 
657     if (channel_mode_bitmap & AVDTP_SBC_MONO){
658         num_channels = 1;
659     }
660     if ( (channel_mode_bitmap & AVDTP_SBC_JOINT_STEREO) ||
661          (channel_mode_bitmap & AVDTP_SBC_STEREO) ||
662          (channel_mode_bitmap & AVDTP_SBC_DUAL_CHANNEL) ){
663         num_channels = 2;
664     }
665 
666     if (sampling_frequency_bitmap & AVDTP_SBC_16000){
667         sampling_frequency = 16000;
668     }
669     if (sampling_frequency_bitmap & AVDTP_SBC_32000){
670         sampling_frequency = 32000;
671     }
672     if (sampling_frequency_bitmap & AVDTP_SBC_44100){
673         sampling_frequency = 44100;
674     }
675     if (sampling_frequency_bitmap & AVDTP_SBC_48000){
676         sampling_frequency = 48000;
677     }
678 
679     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_4){
680         subbands = 4;
681     }
682     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_8){
683         subbands = 8;
684     }
685 
686     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_4){
687         block_length = 4;
688     }
689     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_8){
690         block_length = 8;
691     }
692     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_12){
693         block_length = 12;
694     }
695     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_16){
696         block_length = 16;
697     }
698 
699     event[pos++] = media_codec.media_type;
700     little_endian_store_16(event, pos, sampling_frequency);
701     pos += 2;
702 
703     event[pos++] = channel_mode_bitmap;
704     event[pos++] = num_channels;
705     event[pos++] = block_length;
706     event[pos++] = subbands;
707     event[pos++] = media_codec.media_codec_information[1] & 0x03;
708     event[pos++] = media_codec.media_codec_information[2];
709     event[pos++] = media_codec.media_codec_information[3];
710     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
711 }
712 
713 void avdtp_signaling_emit_media_codec_sbc_configuration(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, adtvp_media_codec_capabilities_t media_codec){
714     if (!callback) return;
715     avdtp_signaling_emit_media_codec_sbc(callback, avdtp_cid, int_seid, acp_seid, media_codec, 0);
716 }
717 
718 void avdtp_signaling_emit_media_codec_sbc_reconfiguration(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, adtvp_media_codec_capabilities_t media_codec){
719     if (!callback) return;
720     avdtp_signaling_emit_media_codec_sbc(callback, avdtp_cid, int_seid, acp_seid, media_codec, 1);
721 }
722 
723 static inline void avdtp_signaling_emit_media_codec_other(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, adtvp_media_codec_capabilities_t media_codec, uint8_t reconfigure){
724     uint8_t event[112];
725     int pos = 0;
726     event[pos++] = HCI_EVENT_AVDTP_META;
727     event[pos++] = sizeof(event) - 2;
728     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CONFIGURATION;
729     little_endian_store_16(event, pos, avdtp_cid);
730     pos += 2;
731     event[pos++] = int_seid;
732     event[pos++] = acp_seid;
733     event[pos++] = reconfigure;
734 
735     event[pos++] = media_codec.media_type;
736     little_endian_store_16(event, pos, media_codec.media_codec_type);
737     pos += 2;
738     little_endian_store_16(event, pos, media_codec.media_codec_information_len);
739     pos += 2;
740 
741     if (media_codec.media_codec_information_len < 100){
742         memcpy(event+pos, media_codec.media_codec_information, media_codec.media_codec_information_len);
743     } else {
744         memcpy(event+pos, media_codec.media_codec_information, 100);
745     }
746     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
747 }
748 
749 void avdtp_signaling_emit_media_codec_other_configuration(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, adtvp_media_codec_capabilities_t media_codec){
750     if (!callback) return;
751     avdtp_signaling_emit_media_codec_other(callback, avdtp_cid, int_seid, acp_seid, media_codec, 0);
752 }
753 
754 void avdtp_signaling_emit_media_codec_other_reconfiguration(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, uint8_t acp_seid, adtvp_media_codec_capabilities_t media_codec){
755     if (!callback) return;
756     avdtp_signaling_emit_media_codec_other(callback, avdtp_cid, int_seid, acp_seid, media_codec, 1);
757 }
758 
759 
760 void avdtp_request_can_send_now_acceptor(avdtp_connection_t * connection, uint16_t l2cap_cid){
761     connection->wait_to_send_acceptor = 1;
762     l2cap_request_can_send_now_event(l2cap_cid);
763 }
764 void avdtp_request_can_send_now_initiator(avdtp_connection_t * connection, uint16_t l2cap_cid){
765     connection->wait_to_send_initiator = 1;
766     l2cap_request_can_send_now_event(l2cap_cid);
767 }
768 void avdtp_request_can_send_now_self(avdtp_connection_t * connection, uint16_t l2cap_cid){
769     connection->wait_to_send_self = 1;
770     l2cap_request_can_send_now_event(l2cap_cid);
771 }
772 
773 uint8_t avdtp_get_index_of_remote_stream_endpoint_with_seid(avdtp_stream_endpoint_t * stream_endpoint, uint16_t seid){
774     if (!stream_endpoint->connection) return AVDTP_INVALID_SEP_INDEX;
775     if (stream_endpoint->connection->remote_seps[stream_endpoint->remote_sep_index].seid == seid){
776         return stream_endpoint->remote_sep_index;
777     }
778     int i;
779     for (i=0; i < stream_endpoint->connection->remote_seps_num; i++){
780         if (stream_endpoint->connection->remote_seps[i].seid == seid){
781             return i;
782         }
783     }
784     return AVDTP_INVALID_SEP_INDEX;
785 }
786 
787 uint8_t avdtp_find_remote_sep(avdtp_connection_t * connection, uint8_t remote_seid){
788     if (!connection) return AVDTP_INVALID_SEP_INDEX;
789     int i;
790     for (i = 0; i < connection->remote_seps_num; i++){
791         if (connection->remote_seps[i].seid == remote_seid){
792             return i;
793         }
794     }
795     return AVDTP_INVALID_SEP_INDEX;
796 }
797