xref: /btstack/src/classic/avdtp_util.c (revision de804f9e40fa10b2ead91db28fa5571afa6ec08a)
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 void avdtp_initialize_stream_endpoint(avdtp_stream_endpoint_t * stream_endpoint){
51     stream_endpoint->connection = NULL;
52     stream_endpoint->state = AVDTP_STREAM_ENDPOINT_IDLE;
53     stream_endpoint->acceptor_config_state = AVDTP_ACCEPTOR_STREAM_CONFIG_IDLE;
54     stream_endpoint->initiator_config_state = AVDTP_INITIATOR_STREAM_CONFIG_IDLE;
55     stream_endpoint->remote_sep_index = AVDTP_INVALID_SEP_INDEX;
56     stream_endpoint->media_disconnect = 0;
57     stream_endpoint->sep.in_use = 0;
58     stream_endpoint->remote_sep_index = 0;
59 }
60 
61 avdtp_stream_endpoint_t * avdtp_stream_endpoint_for_seid(uint16_t seid, avdtp_context_t * context){
62     btstack_linked_list_iterator_t it;
63     btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
64     while (btstack_linked_list_iterator_has_next(&it)){
65         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
66         if (stream_endpoint->sep.seid == seid){
67             return stream_endpoint;
68         }
69     }
70     return NULL;
71 }
72 
73 avdtp_connection_t * avdtp_connection_for_bd_addr(bd_addr_t addr, avdtp_context_t * context){
74     btstack_linked_list_iterator_t it;
75     btstack_linked_list_iterator_init(&it, &context->connections);
76     while (btstack_linked_list_iterator_has_next(&it)){
77         avdtp_connection_t * connection = (avdtp_connection_t *)btstack_linked_list_iterator_next(&it);
78         if (memcmp(addr, connection->remote_addr, 6) != 0) continue;
79         return connection;
80     }
81     return NULL;
82 }
83 
84 avdtp_connection_t * avdtp_connection_for_l2cap_signaling_cid(uint16_t l2cap_cid, avdtp_context_t * context){
85     btstack_linked_list_iterator_t it;
86     btstack_linked_list_iterator_init(&it, &context->connections);
87     while (btstack_linked_list_iterator_has_next(&it)){
88         avdtp_connection_t * connection = (avdtp_connection_t *)btstack_linked_list_iterator_next(&it);
89         if (connection->l2cap_signaling_cid != l2cap_cid) continue;
90         return connection;
91     }
92     return NULL;
93 }
94 
95 avdtp_stream_endpoint_t * avdtp_stream_endpoint_for_l2cap_cid(uint16_t l2cap_cid, avdtp_context_t * context){
96     btstack_linked_list_iterator_t it;
97     btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
98     while (btstack_linked_list_iterator_has_next(&it)){
99         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
100         if (stream_endpoint->l2cap_media_cid == l2cap_cid){
101             return stream_endpoint;
102         }
103         if (stream_endpoint->l2cap_reporting_cid == l2cap_cid){
104             return stream_endpoint;
105         }
106         if (stream_endpoint->l2cap_recovery_cid == l2cap_cid){
107             return stream_endpoint;
108         }
109     }
110     return NULL;
111 }
112 
113 avdtp_stream_endpoint_t * avdtp_stream_endpoint_with_seid(uint8_t seid, avdtp_context_t * context){
114     btstack_linked_list_iterator_t it;
115     btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
116     while (btstack_linked_list_iterator_has_next(&it)){
117         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
118         if (stream_endpoint->sep.seid == seid){
119             return stream_endpoint;
120         }
121     }
122     return NULL;
123 }
124 
125 avdtp_stream_endpoint_t * avdtp_stream_endpoint_associated_with_acp_seid(uint16_t acp_seid, avdtp_context_t * context){
126     btstack_linked_list_iterator_t it;
127     btstack_linked_list_iterator_init(&it, &context->stream_endpoints);
128     while (btstack_linked_list_iterator_has_next(&it)){
129         avdtp_stream_endpoint_t * stream_endpoint = (avdtp_stream_endpoint_t *)btstack_linked_list_iterator_next(&it);
130 
131         if (stream_endpoint->remote_sep_index != AVDTP_INVALID_SEP_INDEX){
132             if (!stream_endpoint->connection) continue;
133             if (stream_endpoint->connection->remote_seps[stream_endpoint->remote_sep_index].seid == acp_seid){
134                 return stream_endpoint;
135             }
136         }
137     }
138     return NULL;
139 }
140 
141 int get_bit16(uint16_t bitmap, int position){
142     return (bitmap >> position) & 1;
143 }
144 
145 uint8_t store_bit16(uint16_t bitmap, int position, uint8_t value){
146     if (value){
147         bitmap |= 1 << position;
148     } else {
149         bitmap &= ~ (1 << position);
150     }
151     return bitmap;
152 }
153 
154 int avdtp_read_signaling_header(avdtp_signaling_packet_t * signaling_header, uint8_t * packet, uint16_t size){
155     int pos = 0;
156     if (size < 2) return pos;
157     signaling_header->transaction_label = packet[pos] >> 4;
158     signaling_header->packet_type = (avdtp_packet_type_t)((packet[pos] >> 2) & 0x03);
159     signaling_header->message_type = (avdtp_message_type_t) (packet[pos] & 0x03);
160     pos++;
161     memset(signaling_header->command, 0, sizeof(signaling_header->command));
162     switch (signaling_header->packet_type){
163         case AVDTP_SINGLE_PACKET:
164             signaling_header->num_packets = 0;
165             signaling_header->offset = 0;
166             signaling_header->size = 0;
167             break;
168         case AVDTP_END_PACKET:
169             signaling_header->num_packets = 0;
170             break;
171         case AVDTP_START_PACKET:
172             signaling_header->num_packets = packet[pos++];
173             signaling_header->size = 0;
174             signaling_header->offset = 0;
175             break;
176         case AVDTP_CONTINUE_PACKET:
177             if (signaling_header->num_packets <= 0) {
178                 log_info("    ERROR: wrong num fragmented packets\n");
179                 break;
180             }
181             signaling_header->num_packets--;
182             break;
183     }
184     signaling_header->signal_identifier = (avdtp_signal_identifier_t)(packet[pos++] & 0x3f);
185     return pos;
186 }
187 
188 int avdtp_pack_service_capabilities(uint8_t * buffer, int size, avdtp_capabilities_t caps, avdtp_service_category_t category, uint8_t pack_all_capabilities){
189     UNUSED(size);
190 
191     int i;
192     // pos = 0 reserved for length
193     int pos = 1;
194     switch(category){
195         case AVDTP_MEDIA_TRANSPORT:
196         case AVDTP_REPORTING:
197             break;
198         case AVDTP_DELAY_REPORTING:
199             if (!pack_all_capabilities) break;
200             break;
201         case AVDTP_RECOVERY:
202             buffer[pos++] = caps.recovery.recovery_type; // 0x01=RFC2733
203             buffer[pos++] = caps.recovery.maximum_recovery_window_size;
204             buffer[pos++] = caps.recovery.maximum_number_media_packets;
205             break;
206         case AVDTP_CONTENT_PROTECTION:
207             buffer[pos++] = caps.content_protection.cp_type_value_len + 2;
208             big_endian_store_16(buffer, pos, caps.content_protection.cp_type);
209             pos += 2;
210             memcpy(buffer+pos, caps.content_protection.cp_type_value, caps.content_protection.cp_type_value_len);
211             break;
212         case AVDTP_HEADER_COMPRESSION:
213             buffer[pos++] = (caps.header_compression.back_ch << 7) | (caps.header_compression.media << 6) | (caps.header_compression.recovery << 5);
214             break;
215         case AVDTP_MULTIPLEXING:
216             buffer[pos++] = caps.multiplexing_mode.fragmentation << 7;
217             for (i=0; i<caps.multiplexing_mode.transport_identifiers_num; i++){
218                 buffer[pos++] = caps.multiplexing_mode.transport_session_identifiers[i] << 7;
219                 buffer[pos++] = caps.multiplexing_mode.tcid[i] << 7;
220                 // media, reporting. recovery
221             }
222             break;
223         case AVDTP_MEDIA_CODEC:
224             buffer[pos++] = ((uint8_t)caps.media_codec.media_type) << 4;
225             buffer[pos++] = (uint8_t)caps.media_codec.media_codec_type;
226             for (i = 0; i<caps.media_codec.media_codec_information_len; i++){
227                 buffer[pos++] = caps.media_codec.media_codec_information[i];
228             }
229             break;
230         default:
231             break;
232     }
233     buffer[0] = pos - 1; // length
234     return pos;
235 }
236 
237 static int avdtp_unpack_service_capabilities_has_errors(avdtp_connection_t * connection, avdtp_service_category_t category, uint8_t cap_len){
238     connection->error_code = 0;
239 
240     if (category == AVDTP_SERVICE_CATEGORY_INVALID_0 ||
241         (category == AVDTP_SERVICE_CATEGORY_INVALID_FF && connection->signaling_packet.signal_identifier == AVDTP_SI_RECONFIGURE)){
242         log_info("    ERROR: BAD SERVICE CATEGORY %d\n", category);
243         connection->reject_service_category = category;
244         connection->error_code = BAD_SERV_CATEGORY;
245         return 1;
246     }
247 
248     if (connection->signaling_packet.signal_identifier == AVDTP_SI_RECONFIGURE){
249         if (category != AVDTP_CONTENT_PROTECTION && category != AVDTP_MEDIA_CODEC){
250             log_info("    ERROR: REJECT CATEGORY, INVALID_CAPABILITIES\n");
251             connection->reject_service_category = category;
252             connection->error_code = INVALID_CAPABILITIES;
253             return 1;
254         }
255     }
256 
257     switch(category){
258         case AVDTP_MEDIA_TRANSPORT:
259             if (cap_len != 0){
260                 log_info("    ERROR: REJECT CATEGORY, BAD_MEDIA_TRANSPORT\n");
261                 connection->reject_service_category = category;
262                 connection->error_code = BAD_MEDIA_TRANSPORT_FORMAT;
263                 return 1;
264             }
265             break;
266         case AVDTP_REPORTING:
267         case AVDTP_DELAY_REPORTING:
268             if (cap_len != 0){
269                 log_info("    ERROR: REJECT CATEGORY, BAD_LENGTH\n");
270                 connection->reject_service_category = category;
271                 connection->error_code = BAD_LENGTH;
272                 return 1;
273             }
274             break;
275         case AVDTP_RECOVERY:
276             if (cap_len < 3){
277                 log_info("    ERROR: REJECT CATEGORY, BAD_MEDIA_TRANSPORT\n");
278                 connection->reject_service_category = category;
279                 connection->error_code = BAD_RECOVERY_FORMAT;
280                 return 1;
281             }
282             break;
283         case AVDTP_CONTENT_PROTECTION:
284             if (cap_len < 2){
285                 log_info("    ERROR: REJECT CATEGORY, BAD_CP_FORMAT\n");
286                 connection->reject_service_category = category;
287                 connection->error_code = BAD_CP_FORMAT;
288                 return 1;
289             }
290             break;
291         case AVDTP_HEADER_COMPRESSION:
292             break;
293         case AVDTP_MULTIPLEXING:
294             break;
295         case AVDTP_MEDIA_CODEC:
296             break;
297         default:
298             break;
299     }
300     return 0;
301 }
302 
303 uint16_t avdtp_unpack_service_capabilities(avdtp_connection_t * connection, avdtp_capabilities_t * caps, uint8_t * packet, uint16_t size){
304     if (size == 0) return 0;
305 
306     uint16_t registered_service_categories = 0;
307     int pos = 0;
308     int i;
309     avdtp_service_category_t category = (avdtp_service_category_t)packet[pos++];
310     uint8_t cap_len = packet[pos++];
311 
312     if (avdtp_unpack_service_capabilities_has_errors(connection, category, cap_len)) return 0;
313     int processed_cap_len = 0;
314     int rfa = 0;
315 
316     while (pos < size){
317         if (cap_len > size - pos){
318             connection->reject_service_category = category;
319             connection->error_code = BAD_LENGTH;
320             return 0;
321         }
322         rfa = 0;
323         processed_cap_len = pos;
324         switch(category){
325             case AVDTP_RECOVERY:
326                 caps->recovery.recovery_type = packet[pos++];
327                 caps->recovery.maximum_recovery_window_size = packet[pos++];
328                 caps->recovery.maximum_number_media_packets = packet[pos++];
329                 break;
330             case AVDTP_CONTENT_PROTECTION:
331                 caps->content_protection.cp_type = big_endian_read_16(packet, pos);
332                 pos+=2;
333 
334                 caps->content_protection.cp_type_value_len = cap_len - 2;
335                 pos += caps->content_protection.cp_type_value_len;
336 
337                 // connection->reject_service_category = category;
338                 // connection->error_code = UNSUPPORTED_CONFIGURATION;
339                 // support for content protection goes here
340                 break;
341 
342             case AVDTP_HEADER_COMPRESSION:
343                 caps->header_compression.back_ch  = packet[pos] >> 7;
344                 caps->header_compression.media    = packet[pos] >> 6;
345                 caps->header_compression.recovery = packet[pos] >> 5;
346                 pos++;
347                 break;
348             case AVDTP_MULTIPLEXING:
349                 caps->multiplexing_mode.fragmentation = packet[pos++] >> 7;
350                 // read [tsid, tcid] for media, reporting. recovery respectively
351                 caps->multiplexing_mode.transport_identifiers_num = 3;
352                 for (i=0; i<caps->multiplexing_mode.transport_identifiers_num; i++){
353                     caps->multiplexing_mode.transport_session_identifiers[i] = packet[pos++] >> 7;
354                     caps->multiplexing_mode.tcid[i] = packet[pos++] >> 7;
355                 }
356                 break;
357             case AVDTP_MEDIA_CODEC:
358                 caps->media_codec.media_type = (avdtp_media_type_t)(packet[pos++] >> 4);
359                 caps->media_codec.media_codec_type = (avdtp_media_codec_type_t)(packet[pos++]);
360                 caps->media_codec.media_codec_information_len = cap_len - 2;
361                 caps->media_codec.media_codec_information = &packet[pos];
362                 pos += caps->media_codec.media_codec_information_len;
363                 break;
364             case AVDTP_MEDIA_TRANSPORT:
365             case AVDTP_REPORTING:
366             case AVDTP_DELAY_REPORTING:
367                 pos += cap_len;
368                 break;
369             default:
370                 pos += cap_len;
371                 rfa = 1;
372                 break;
373         }
374         processed_cap_len = pos - processed_cap_len;
375 
376         if (cap_len == processed_cap_len){
377             if (!rfa) {
378                 registered_service_categories = store_bit16(registered_service_categories, category, 1);
379             }
380             if (pos < size-2){
381                 //int old_pos = pos;
382                 category = (avdtp_service_category_t)packet[pos++];
383                 cap_len = packet[pos++];
384                 if (avdtp_unpack_service_capabilities_has_errors(connection, category, cap_len)) return 0;
385             }
386         }
387     }
388     return registered_service_categories;
389 }
390 
391 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){
392     if (signaling_packet->offset) return;
393     uint8_t pack_all_capabilities = 1;
394     signaling_packet->message_type = AVDTP_RESPONSE_ACCEPT_MSG;
395     int i;
396 
397     signaling_packet->size = 0;
398     memset(signaling_packet->command, 0 , sizeof(signaling_packet->command));
399 
400 
401     switch (identifier) {
402         case AVDTP_SI_GET_CAPABILITIES:
403             pack_all_capabilities = 0;
404             break;
405         case AVDTP_SI_GET_ALL_CAPABILITIES:
406             pack_all_capabilities = 1;
407             break;
408         case AVDTP_SI_SET_CONFIGURATION:
409             signaling_packet->command[signaling_packet->size++] = signaling_packet->acp_seid << 2;
410             signaling_packet->command[signaling_packet->size++] = signaling_packet->int_seid << 2;
411             signaling_packet->message_type = AVDTP_CMD_MSG;
412             break;
413         case AVDTP_SI_RECONFIGURE:
414             signaling_packet->command[signaling_packet->size++] = signaling_packet->acp_seid << 2;
415             signaling_packet->message_type = AVDTP_CMD_MSG;
416             break;
417         default:
418             log_error("avdtp_prepare_capabilities wrong identifier %d", identifier);
419             break;
420     }
421 
422     for (i = 1; i < 9; i++){
423         int registered_category = get_bit16(registered_service_categories, i);
424         if (!registered_category && (identifier == AVDTP_SI_SET_CONFIGURATION || identifier == AVDTP_SI_RECONFIGURE)){
425             // TODO: introduce bitmap of mandatory categories
426             if (i == 1){
427                 registered_category = 1;
428             }
429         }
430         if (registered_category){
431             // service category
432             signaling_packet->command[signaling_packet->size++] = i;
433             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);
434         }
435     }
436 
437     signaling_packet->signal_identifier = (avdtp_signal_identifier_t)identifier;
438     signaling_packet->transaction_label = transaction_label;
439 }
440 
441 int avdtp_signaling_create_fragment(uint16_t cid, avdtp_signaling_packet_t * signaling_packet, uint8_t * out_buffer) {
442     int mtu = l2cap_get_remote_mtu_for_local_cid(cid);
443     int data_len = 0;
444 
445     uint16_t offset = signaling_packet->offset;
446     uint16_t pos = 1;
447 
448     if (offset == 0){
449         if (signaling_packet->size <= mtu - 2){
450             signaling_packet->packet_type = AVDTP_SINGLE_PACKET;
451             out_buffer[pos++] = signaling_packet->signal_identifier;
452             data_len = signaling_packet->size;
453         } else {
454             signaling_packet->packet_type = AVDTP_START_PACKET;
455             out_buffer[pos++] = (mtu + signaling_packet->size)/ (mtu-1);
456             out_buffer[pos++] = signaling_packet->signal_identifier;
457             data_len = mtu - 3;
458             signaling_packet->offset = data_len;
459         }
460     } else {
461         int remaining_bytes = signaling_packet->size - offset;
462         if (remaining_bytes <= mtu - 1){
463             signaling_packet->packet_type = AVDTP_END_PACKET;
464             data_len = remaining_bytes;
465             signaling_packet->offset = 0;
466         } else{
467             signaling_packet->packet_type = AVDTP_CONTINUE_PACKET;
468             data_len = mtu - 1;
469             signaling_packet->offset += data_len;
470         }
471     }
472     out_buffer[0] = avdtp_header(signaling_packet->transaction_label, signaling_packet->packet_type, signaling_packet->message_type);
473     memcpy(out_buffer+pos, signaling_packet->command + offset, data_len);
474     pos += data_len;
475     return pos;
476 }
477 
478 
479 void avdtp_signaling_emit_connection_established(btstack_packet_handler_t callback, uint16_t avdtp_cid, bd_addr_t addr, uint8_t status){
480     if (!callback) return;
481     uint8_t event[12];
482     int pos = 0;
483     event[pos++] = HCI_EVENT_AVDTP_META;
484     event[pos++] = sizeof(event) - 2;
485     event[pos++] = AVDTP_SUBEVENT_SIGNALING_CONNECTION_ESTABLISHED;
486     little_endian_store_16(event, pos, avdtp_cid);
487     pos += 2;
488     reverse_bd_addr(addr,&event[pos]);
489     pos += 6;
490     event[pos++] = status;
491     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
492 }
493 
494 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){
495     if (!callback) return;
496     uint8_t event[8];
497     int pos = 0;
498     event[pos++] = HCI_EVENT_AVDTP_META;
499     event[pos++] = sizeof(event) - 2;
500     event[pos++] = AVDTP_SUBEVENT_STREAMING_CAN_SEND_MEDIA_PACKET_NOW;
501     little_endian_store_16(event, pos, avdtp_cid);
502     pos += 2;
503     event[pos++] = seid;
504     little_endian_store_16(event, pos, sequence_number);
505     pos += 2;
506     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
507 }
508 
509 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){
510     if (!callback) return;
511     uint8_t event[8];
512     int pos = 0;
513     event[pos++] = HCI_EVENT_AVDTP_META;
514     event[pos++] = sizeof(event) - 2;
515     event[pos++] = AVDTP_SUBEVENT_STREAMING_CONNECTION_ESTABLISHED;
516     little_endian_store_16(event, pos, avdtp_cid);
517     pos += 2;
518     event[pos++] = int_seid;
519     event[pos++] = acp_seid;
520     event[pos++] = status;
521     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
522 }
523 
524 void avdtp_signaling_emit_sep(btstack_packet_handler_t callback, uint16_t avdtp_cid, avdtp_sep_t sep){
525     if (!callback) return;
526     uint8_t event[9];
527     int pos = 0;
528     event[pos++] = HCI_EVENT_AVDTP_META;
529     event[pos++] = sizeof(event) - 2;
530     event[pos++] = AVDTP_SUBEVENT_SIGNALING_SEP_FOUND;
531     little_endian_store_16(event, pos, avdtp_cid);
532     pos += 2;
533     event[pos++] = sep.seid;
534     event[pos++] = sep.in_use;
535     event[pos++] = sep.media_type;
536     event[pos++] = sep.type;
537     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
538 }
539 
540 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){
541     if (!callback) return;
542     uint8_t event[8];
543     int pos = 0;
544     event[pos++] = HCI_EVENT_AVDTP_META;
545     event[pos++] = sizeof(event) - 2;
546     event[pos++] = AVDTP_SUBEVENT_SIGNALING_ACCEPT;
547     little_endian_store_16(event, pos, avdtp_cid);
548     pos += 2;
549     event[pos++] = int_seid;
550     event[pos++] = identifier;
551     event[pos++] = status;
552     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
553 }
554 
555 void avdtp_signaling_emit_reject(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, avdtp_signal_identifier_t identifier){
556     if (!callback) return;
557     uint8_t event[7];
558     int pos = 0;
559     event[pos++] = HCI_EVENT_AVDTP_META;
560     event[pos++] = sizeof(event) - 2;
561     event[pos++] = AVDTP_SUBEVENT_SIGNALING_REJECT;
562     little_endian_store_16(event, pos, avdtp_cid);
563     pos += 2;
564     event[pos++] = int_seid;
565     event[pos++] = identifier;
566     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
567 }
568 
569 void avdtp_signaling_emit_general_reject(btstack_packet_handler_t callback, uint16_t avdtp_cid, uint8_t int_seid, avdtp_signal_identifier_t identifier){
570     if (!callback) return;
571     uint8_t event[7];
572     int pos = 0;
573     event[pos++] = HCI_EVENT_AVDTP_META;
574     event[pos++] = sizeof(event) - 2;
575     event[pos++] = AVDTP_SUBEVENT_SIGNALING_GENERAL_REJECT;
576     little_endian_store_16(event, pos, avdtp_cid);
577     pos += 2;
578     event[pos++] = int_seid;
579     event[pos++] = identifier;
580     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
581 }
582 
583 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){
584     if (!callback) return;
585     uint8_t event[15];
586     int pos = 0;
587     event[pos++] = HCI_EVENT_AVDTP_META;
588     event[pos++] = sizeof(event) - 2;
589     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CAPABILITY;
590     little_endian_store_16(event, pos, avdtp_cid);
591     pos += 2;
592     event[pos++] = int_seid;
593     event[pos++] = acp_seid;
594     event[pos++] = media_codec.media_type;
595     event[pos++] = media_codec.media_codec_information[0] >> 4;
596     event[pos++] = media_codec.media_codec_information[0] & 0x0F;
597     event[pos++] = media_codec.media_codec_information[1] >> 4;
598     event[pos++] = (media_codec.media_codec_information[1] & 0x0F) >> 2;
599     event[pos++] = media_codec.media_codec_information[1] & 0x03;
600     event[pos++] = media_codec.media_codec_information[2];
601     event[pos++] = media_codec.media_codec_information[3];
602     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
603 }
604 
605 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){
606     if (!callback) return;
607         uint8_t event[111];
608     int pos = 0;
609     event[pos++] = HCI_EVENT_AVDTP_META;
610     event[pos++] = sizeof(event) - 2;
611     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CAPABILITY;
612     little_endian_store_16(event, pos, avdtp_cid);
613     pos += 2;
614     event[pos++] = int_seid;
615     event[pos++] = acp_seid;
616     event[pos++] = media_codec.media_type;
617     little_endian_store_16(event, pos, media_codec.media_codec_type);
618     pos += 2;
619     little_endian_store_16(event, pos, media_codec.media_codec_information_len);
620     pos += 2;
621     if (media_codec.media_codec_information_len < 100){
622         memcpy(event+pos, media_codec.media_codec_information, media_codec.media_codec_information_len);
623     } else {
624         memcpy(event+pos, media_codec.media_codec_information, 100);
625     }
626     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
627 }
628 
629 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){
630     if (!callback) return;
631     uint8_t event[16+2];
632     int pos = 0;
633     event[pos++] = HCI_EVENT_AVDTP_META;
634     event[pos++] = sizeof(event) - 2;
635 
636     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_SBC_CONFIGURATION;
637     little_endian_store_16(event, pos, avdtp_cid);
638     pos += 2;
639     event[pos++] = int_seid;
640     event[pos++] = acp_seid;
641     event[pos++] = reconfigure;
642 
643     uint8_t num_channels = 0;
644     uint16_t sampling_frequency = 0;
645     uint8_t subbands = 0;
646     uint8_t block_length = 0;
647 
648     uint8_t sampling_frequency_bitmap = media_codec.media_codec_information[0] >> 4;
649     uint8_t channel_mode_bitmap = media_codec.media_codec_information[0] & 0x0F;
650     uint8_t block_length_bitmap = media_codec.media_codec_information[1] >> 4;
651     uint8_t subbands_bitmap = (media_codec.media_codec_information[1] & 0x0F) >> 2;
652 
653     if (channel_mode_bitmap & AVDTP_SBC_MONO){
654         num_channels = 1;
655     }
656     if ( (channel_mode_bitmap & AVDTP_SBC_JOINT_STEREO) ||
657          (channel_mode_bitmap & AVDTP_SBC_STEREO) ||
658          (channel_mode_bitmap & AVDTP_SBC_DUAL_CHANNEL) ){
659         num_channels = 2;
660     }
661 
662     if (sampling_frequency_bitmap & AVDTP_SBC_16000){
663         sampling_frequency = 16000;
664     }
665     if (sampling_frequency_bitmap & AVDTP_SBC_32000){
666         sampling_frequency = 32000;
667     }
668     if (sampling_frequency_bitmap & AVDTP_SBC_44100){
669         sampling_frequency = 44100;
670     }
671     if (sampling_frequency_bitmap & AVDTP_SBC_48000){
672         sampling_frequency = 48000;
673     }
674 
675     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_4){
676         subbands = 4;
677     }
678     if (subbands_bitmap & AVDTP_SBC_SUBBANDS_8){
679         subbands = 8;
680     }
681 
682     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_4){
683         block_length = 4;
684     }
685     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_8){
686         block_length = 8;
687     }
688     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_12){
689         block_length = 12;
690     }
691     if (block_length_bitmap & AVDTP_SBC_BLOCK_LENGTH_16){
692         block_length = 16;
693     }
694 
695     event[pos++] = media_codec.media_type;
696     little_endian_store_16(event, pos, sampling_frequency);
697     pos += 2;
698 
699     event[pos++] = channel_mode_bitmap;
700     event[pos++] = num_channels;
701     event[pos++] = block_length;
702     event[pos++] = subbands;
703     event[pos++] = media_codec.media_codec_information[1] & 0x03;
704     event[pos++] = media_codec.media_codec_information[2];
705     event[pos++] = media_codec.media_codec_information[3];
706     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
707 }
708 
709 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){
710     if (!callback) return;
711     avdtp_signaling_emit_media_codec_sbc(callback, avdtp_cid, int_seid, acp_seid, media_codec, 0);
712 }
713 
714 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){
715     if (!callback) return;
716     avdtp_signaling_emit_media_codec_sbc(callback, avdtp_cid, int_seid, acp_seid, media_codec, 1);
717 }
718 
719 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){
720     uint8_t event[112];
721     int pos = 0;
722     event[pos++] = HCI_EVENT_AVDTP_META;
723     event[pos++] = sizeof(event) - 2;
724     event[pos++] = AVDTP_SUBEVENT_SIGNALING_MEDIA_CODEC_OTHER_CONFIGURATION;
725     little_endian_store_16(event, pos, avdtp_cid);
726     pos += 2;
727     event[pos++] = int_seid;
728     event[pos++] = acp_seid;
729     event[pos++] = reconfigure;
730 
731     event[pos++] = media_codec.media_type;
732     little_endian_store_16(event, pos, media_codec.media_codec_type);
733     pos += 2;
734     little_endian_store_16(event, pos, media_codec.media_codec_information_len);
735     pos += 2;
736 
737     if (media_codec.media_codec_information_len < 100){
738         memcpy(event+pos, media_codec.media_codec_information, media_codec.media_codec_information_len);
739     } else {
740         memcpy(event+pos, media_codec.media_codec_information, 100);
741     }
742     (*callback)(HCI_EVENT_PACKET, 0, event, sizeof(event));
743 }
744 
745 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){
746     if (!callback) return;
747     avdtp_signaling_emit_media_codec_other(callback, avdtp_cid, int_seid, acp_seid, media_codec, 0);
748 }
749 
750 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){
751     if (!callback) return;
752     avdtp_signaling_emit_media_codec_other(callback, avdtp_cid, int_seid, acp_seid, media_codec, 1);
753 }
754 
755 
756 void avdtp_request_can_send_now_acceptor(avdtp_connection_t * connection, uint16_t l2cap_cid){
757     connection->wait_to_send_acceptor = 1;
758     l2cap_request_can_send_now_event(l2cap_cid);
759 }
760 void avdtp_request_can_send_now_initiator(avdtp_connection_t * connection, uint16_t l2cap_cid){
761     connection->wait_to_send_initiator = 1;
762     l2cap_request_can_send_now_event(l2cap_cid);
763 }
764 void avdtp_request_can_send_now_self(avdtp_connection_t * connection, uint16_t l2cap_cid){
765     connection->wait_to_send_self = 1;
766     l2cap_request_can_send_now_event(l2cap_cid);
767 }
768 
769 uint8_t avdtp_get_index_of_remote_stream_endpoint_with_seid(avdtp_stream_endpoint_t * stream_endpoint, uint16_t seid){
770     if (!stream_endpoint->connection) return AVDTP_INVALID_SEP_INDEX;
771     if (stream_endpoint->connection->remote_seps[stream_endpoint->remote_sep_index].seid == seid){
772         return stream_endpoint->remote_sep_index;
773     }
774     int i;
775     for (i=0; i < stream_endpoint->connection->remote_seps_num; i++){
776         if (stream_endpoint->connection->remote_seps[i].seid == seid){
777             return i;
778         }
779     }
780     return AVDTP_INVALID_SEP_INDEX;
781 }
782 
783 uint8_t avdtp_find_remote_sep(avdtp_connection_t * connection, uint8_t remote_seid){
784     if (!connection) return AVDTP_INVALID_SEP_INDEX;
785     int i;
786     for (i = 0; i < connection->remote_seps_num; i++){
787         if (connection->remote_seps[i].seid == remote_seid){
788             return i;
789         }
790     }
791     return AVDTP_INVALID_SEP_INDEX;
792 }
793