xref: /btstack/src/classic/sdp_server.c (revision a8d51f092f1b660d0f6921369ad2bc3f9368296c)
1 /*
2  * Copyright (C) 2014 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__ "sdp_server.c"
39 
40 /*
41  * Implementation of the Service Discovery Protocol Server
42  */
43 
44 #include <string.h>
45 
46 #include "bluetooth.h"
47 #include "bluetooth_psm.h"
48 #include "bluetooth_sdp.h"
49 #include "btstack_debug.h"
50 #include "btstack_event.h"
51 #include "btstack_memory.h"
52 #include "classic/core.h"
53 #include "classic/sdp_server.h"
54 #include "classic/sdp_util.h"
55 #include "hci.h"
56 #include "hci_dump.h"
57 #include "l2cap.h"
58 
59 // max number of incoming l2cap connections that can be queued instead of getting rejected
60 #ifndef SDP_WAITING_LIST_MAX_COUNT
61 #define SDP_WAITING_LIST_MAX_COUNT 8
62 #endif
63 
64 // max reserved ServiceRecordHandle
65 #define maxReservedServiceRecordHandle 0xffff
66 
67 // max SDP response matches L2CAP PDU -- allow to use smaller buffer
68 #ifndef SDP_RESPONSE_BUFFER_SIZE
69 #define SDP_RESPONSE_BUFFER_SIZE (HCI_ACL_PAYLOAD_SIZE-L2CAP_HEADER_SIZE)
70 #endif
71 
72 static void sdp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
73 
74 // registered service records
75 static btstack_linked_list_t sdp_service_records = NULL;
76 
77 // our handles start after the reserved range
78 static uint32_t sdp_next_service_record_handle = ((uint32_t) maxReservedServiceRecordHandle) + 2;
79 
80 static uint8_t sdp_response_buffer[SDP_RESPONSE_BUFFER_SIZE];
81 
82 static uint16_t l2cap_cid = 0;
83 static uint16_t sdp_response_size = 0;
84 static uint16_t l2cap_waiting_list_cids[SDP_WAITING_LIST_MAX_COUNT];
85 static int      l2cap_waiting_list_count;
86 
87 void sdp_init(void){
88     // register with l2cap psm sevices - max MTU
89     l2cap_register_service(sdp_packet_handler, BLUETOOTH_PSM_SDP, 0xffff, LEVEL_0);
90     l2cap_waiting_list_count = 0;
91 }
92 
93 uint32_t sdp_get_service_record_handle(const uint8_t * record){
94     // TODO: make sdp_get_attribute_value_for_attribute_id accept const data to remove cast
95     uint8_t * serviceRecordHandleAttribute = sdp_get_attribute_value_for_attribute_id((uint8_t *)record, BLUETOOTH_ATTRIBUTE_SERVICE_RECORD_HANDLE);
96     if (!serviceRecordHandleAttribute) return 0;
97     if (de_get_element_type(serviceRecordHandleAttribute) != DE_UINT) return 0;
98     if (de_get_size_type(serviceRecordHandleAttribute) != DE_SIZE_32) return 0;
99     return big_endian_read_32(serviceRecordHandleAttribute, 1);
100 }
101 
102 static service_record_item_t * sdp_get_record_item_for_handle(uint32_t handle){
103     btstack_linked_item_t *it;
104     for (it = (btstack_linked_item_t *) sdp_service_records; it ; it = it->next){
105         service_record_item_t * item = (service_record_item_t *) it;
106         if (item->service_record_handle == handle){
107             return item;
108         }
109     }
110     return NULL;
111 }
112 
113 uint8_t * sdp_get_record_for_handle(uint32_t handle){
114     service_record_item_t * record_item =  sdp_get_record_item_for_handle(handle);
115     if (!record_item) return NULL;
116     return record_item->service_record;
117 }
118 
119 // get next free, unregistered service record handle
120 uint32_t sdp_create_service_record_handle(void){
121     uint32_t handle = 0;
122     do {
123         handle = sdp_next_service_record_handle++;
124         if (sdp_get_record_item_for_handle(handle)) handle = 0;
125     } while (handle == 0);
126     return handle;
127 }
128 
129 /**
130  * @brief Register Service Record with database using ServiceRecordHandle stored in record
131  * @pre AttributeIDs are in ascending order
132  * @pre ServiceRecordHandle is first attribute and valid
133  * @param record is not copied!
134  * @result status
135  */
136 uint8_t sdp_register_service(const uint8_t * record){
137 
138     // validate service record handle. it must: exist, be in valid range, not have been already used
139     uint32_t record_handle = sdp_get_service_record_handle(record);
140     if (!record_handle) return SDP_HANDLE_INVALID;
141     if (record_handle <= maxReservedServiceRecordHandle) return SDP_HANDLE_INVALID;
142     if (sdp_get_record_item_for_handle(record_handle)) return SDP_HANDLE_ALREADY_REGISTERED;
143 
144     // alloc memory for new service_record_item
145     service_record_item_t * newRecordItem = btstack_memory_service_record_item_get();
146     if (!newRecordItem) return BTSTACK_MEMORY_ALLOC_FAILED;
147 
148     // set handle and record
149     newRecordItem->service_record_handle = record_handle;
150     newRecordItem->service_record = (uint8_t*) record;
151 
152     // add to linked list
153     btstack_linked_list_add(&sdp_service_records, (btstack_linked_item_t *) newRecordItem);
154 
155     return 0;
156 }
157 
158 //
159 // unregister service record
160 //
161 void sdp_unregister_service(uint32_t service_record_handle){
162     service_record_item_t * record_item = sdp_get_record_item_for_handle(service_record_handle);
163     if (!record_item) return;
164     btstack_linked_list_remove(&sdp_service_records, (btstack_linked_item_t *) record_item);
165     btstack_memory_service_record_item_free(record_item);
166 }
167 
168 // PDU
169 // PDU ID (1), Transaction ID (2), Param Length (2), Param 1, Param 2, ..
170 
171 static int sdp_create_error_response(uint16_t transaction_id, uint16_t error_code){
172     sdp_response_buffer[0] = SDP_ErrorResponse;
173     big_endian_store_16(sdp_response_buffer, 1, transaction_id);
174     big_endian_store_16(sdp_response_buffer, 3, 2);
175     big_endian_store_16(sdp_response_buffer, 5, error_code); // invalid syntax
176     return 7;
177 }
178 
179 int sdp_handle_service_search_request(uint8_t * packet, uint16_t remote_mtu){
180 
181     // get request details
182     uint16_t  transaction_id = big_endian_read_16(packet, 1);
183     uint16_t  param_len = big_endian_read_16(packet, 3);
184     uint8_t * serviceSearchPattern = &packet[5];
185     uint16_t  serviceSearchPatternLen = de_get_len_safe(serviceSearchPattern, param_len);
186     // assert service search pattern is contained
187     if (!serviceSearchPatternLen) return 0;
188     param_len -= serviceSearchPatternLen;
189     // assert max record count is contained
190     if (param_len < 2) return 0;
191     uint16_t  maximumServiceRecordCount = big_endian_read_16(packet, 5 + serviceSearchPatternLen);
192     param_len -= 2;
193     // assert continuation state len is contained in param_len
194     if (param_len < 1) return 0;
195     uint8_t * continuationState = &packet[5+serviceSearchPatternLen+2];
196     // assert continuation state is contained in param_len
197     if ((1 + continuationState[0]) > param_len) return 0;
198 
199     // calc maximumServiceRecordCount based on remote MTU
200     uint16_t maxNrServiceRecordsPerResponse = (remote_mtu - (9+3))/4;
201 
202     // continuation state contains index of next service record to examine
203     int      continuation = 0;
204     uint16_t continuation_index = 0;
205     if (continuationState[0] == 2){
206         continuation_index = big_endian_read_16(continuationState, 1);
207     }
208 
209     // get and limit total count
210     btstack_linked_item_t *it;
211     uint16_t total_service_count   = 0;
212     for (it = (btstack_linked_item_t *) sdp_service_records; it ; it = it->next){
213         service_record_item_t * item = (service_record_item_t *) it;
214         if (!sdp_record_matches_service_search_pattern(item->service_record, serviceSearchPattern)) continue;
215         total_service_count++;
216     }
217     if (total_service_count > maximumServiceRecordCount){
218         total_service_count = maximumServiceRecordCount;
219     }
220 
221     // ServiceRecordHandleList at 9
222     uint16_t pos = 9;
223     uint16_t current_service_count  = 0;
224     uint16_t current_service_index  = 0;
225     uint16_t matching_service_count = 0;
226     for (it = (btstack_linked_item_t *) sdp_service_records; it ; it = it->next, ++current_service_index){
227         service_record_item_t * item = (service_record_item_t *) it;
228 
229         if (!sdp_record_matches_service_search_pattern(item->service_record, serviceSearchPattern)) continue;
230         matching_service_count++;
231 
232         if (current_service_index < continuation_index) continue;
233 
234         big_endian_store_32(sdp_response_buffer, pos, item->service_record_handle);
235         pos += 4;
236         current_service_count++;
237 
238         if (matching_service_count >= total_service_count) break;
239 
240         if (current_service_count >= maxNrServiceRecordsPerResponse){
241             continuation = 1;
242             continuation_index = current_service_index + 1;
243             break;
244         }
245     }
246 
247     // Store continuation state
248     if (continuation) {
249         sdp_response_buffer[pos++] = 2;
250         big_endian_store_16(sdp_response_buffer, pos, continuation_index);
251         pos += 2;
252     } else {
253         sdp_response_buffer[pos++] = 0;
254     }
255 
256     // header
257     sdp_response_buffer[0] = SDP_ServiceSearchResponse;
258     big_endian_store_16(sdp_response_buffer, 1, transaction_id);
259     big_endian_store_16(sdp_response_buffer, 3, pos - 5); // size of variable payload
260     big_endian_store_16(sdp_response_buffer, 5, total_service_count);
261     big_endian_store_16(sdp_response_buffer, 7, current_service_count);
262 
263     return pos;
264 }
265 
266 int sdp_handle_service_attribute_request(uint8_t * packet, uint16_t remote_mtu){
267 
268     // get request details
269     uint16_t  transaction_id = big_endian_read_16(packet, 1);
270     uint16_t  param_len = big_endian_read_16(packet, 3);
271     // assert serviceRecordHandle and maximumAttributeByteCount are in param_len
272     if (param_len < 6) return 0;
273     uint32_t  serviceRecordHandle = big_endian_read_32(packet, 5);
274     uint16_t  maximumAttributeByteCount = big_endian_read_16(packet, 9);
275     param_len -= 6;
276     uint8_t * attributeIDList = &packet[11];
277     uint16_t  attributeIDListLen = de_get_len_safe(attributeIDList, param_len);
278     // assert attributeIDList are in param_len
279     if (!attributeIDListLen) return 0;
280     param_len -= attributeIDListLen;
281     // assert continuation state len is contained in param_len
282     if (param_len < 1) return 0;
283     uint8_t * continuationState = &packet[11+attributeIDListLen];
284     // assert continuation state is contained in param_len
285     if ((1 + continuationState[0]) > param_len) return 0;
286 
287     // calc maximumAttributeByteCount based on remote MTU
288     uint16_t maximumAttributeByteCount2 = remote_mtu - (7+3);
289     if (maximumAttributeByteCount2 < maximumAttributeByteCount) {
290         maximumAttributeByteCount = maximumAttributeByteCount2;
291     }
292 
293     // continuation state contains the offset into the complete response
294     uint16_t continuation_offset = 0;
295     if (continuationState[0] == 2){
296         continuation_offset = big_endian_read_16(continuationState, 1);
297     }
298 
299     // get service record
300     service_record_item_t * item = sdp_get_record_item_for_handle(serviceRecordHandle);
301     if (!item){
302         // service record handle doesn't exist
303         return sdp_create_error_response(transaction_id, 0x0002); /// invalid Service Record Handle
304     }
305 
306 
307     // AttributeList - starts at offset 7
308     uint16_t pos = 7;
309 
310     if (continuation_offset == 0){
311 
312         // get size of this record
313         uint16_t filtered_attributes_size = spd_get_filtered_size(item->service_record, attributeIDList);
314 
315         // store DES
316         de_store_descriptor_with_len(&sdp_response_buffer[pos], DE_DES, DE_SIZE_VAR_16, filtered_attributes_size);
317         maximumAttributeByteCount -= 3;
318         pos += 3;
319     }
320 
321     // copy maximumAttributeByteCount from record
322     uint16_t bytes_used;
323     int complete = sdp_filter_attributes_in_attributeIDList(item->service_record, attributeIDList, continuation_offset, maximumAttributeByteCount, &bytes_used, &sdp_response_buffer[pos]);
324     pos += bytes_used;
325 
326     uint16_t attributeListByteCount = pos - 7;
327 
328     if (complete) {
329         sdp_response_buffer[pos++] = 0;
330     } else {
331         continuation_offset += bytes_used;
332         sdp_response_buffer[pos++] = 2;
333         big_endian_store_16(sdp_response_buffer, pos, continuation_offset);
334         pos += 2;
335     }
336 
337     // header
338     sdp_response_buffer[0] = SDP_ServiceAttributeResponse;
339     big_endian_store_16(sdp_response_buffer, 1, transaction_id);
340     big_endian_store_16(sdp_response_buffer, 3, pos - 5);  // size of variable payload
341     big_endian_store_16(sdp_response_buffer, 5, attributeListByteCount);
342 
343     return pos;
344 }
345 
346 static uint16_t sdp_get_size_for_service_search_attribute_response(uint8_t * serviceSearchPattern, uint8_t * attributeIDList){
347     uint16_t total_response_size = 0;
348     btstack_linked_item_t *it;
349     for (it = (btstack_linked_item_t *) sdp_service_records; it ; it = it->next){
350         service_record_item_t * item = (service_record_item_t *) it;
351 
352         if (!sdp_record_matches_service_search_pattern(item->service_record, serviceSearchPattern)) continue;
353 
354         // for all service records that match
355         total_response_size += 3 + spd_get_filtered_size(item->service_record, attributeIDList);
356     }
357     return total_response_size;
358 }
359 
360 int sdp_handle_service_search_attribute_request(uint8_t * packet, uint16_t remote_mtu){
361 
362     // SDP header before attribute sevice list: 7
363     // Continuation, worst case: 5
364 
365     // get request details
366     uint16_t  transaction_id = big_endian_read_16(packet, 1);
367     uint16_t  param_len = big_endian_read_16(packet, 3);
368     uint8_t * serviceSearchPattern = &packet[5];
369     uint16_t  serviceSearchPatternLen = de_get_len_safe(serviceSearchPattern, param_len);
370     // assert serviceSearchPattern header is contained in param_len
371     if (!serviceSearchPatternLen) return 0;
372     param_len -= serviceSearchPatternLen;
373     // assert maximumAttributeByteCount contained in param_len
374     if (param_len < 2) return 0;
375     uint16_t  maximumAttributeByteCount = big_endian_read_16(packet, 5 + serviceSearchPatternLen);
376     param_len -= 2;
377     uint8_t * attributeIDList = &packet[5+serviceSearchPatternLen+2];
378     uint16_t  attributeIDListLen = de_get_len_safe(attributeIDList, param_len);
379     // assert attributeIDList is contained in param_len
380     if (!attributeIDListLen) return 0;
381     // assert continuation state len is contained in param_len
382     if (param_len < 1) return 0;
383     uint8_t * continuationState = &packet[5+serviceSearchPatternLen+2+attributeIDListLen];
384     // assert continuation state is contained in param_len
385     if ((1 + continuationState[0]) > param_len) return 0;
386 
387     // calc maximumAttributeByteCount based on remote MTU, SDP header and reserved Continuation block
388     uint16_t maximumAttributeByteCount2 = remote_mtu - 12;
389     if (maximumAttributeByteCount2 < maximumAttributeByteCount) {
390         maximumAttributeByteCount = maximumAttributeByteCount2;
391     }
392 
393     // continuation state contains: index of next service record to examine
394     // continuation state contains: byte offset into this service record
395     uint16_t continuation_service_index = 0;
396     uint16_t continuation_offset = 0;
397     if (continuationState[0] == 4){
398         continuation_service_index = big_endian_read_16(continuationState, 1);
399         continuation_offset = big_endian_read_16(continuationState, 3);
400     }
401 
402     // log_info("--> sdp_handle_service_search_attribute_request, cont %u/%u, max %u", continuation_service_index, continuation_offset, maximumAttributeByteCount);
403 
404     // AttributeLists - starts at offset 7
405     uint16_t pos = 7;
406 
407     // add DES with total size for first request
408     if ((continuation_service_index == 0) && (continuation_offset == 0)){
409         uint16_t total_response_size = sdp_get_size_for_service_search_attribute_response(serviceSearchPattern, attributeIDList);
410         de_store_descriptor_with_len(&sdp_response_buffer[pos], DE_DES, DE_SIZE_VAR_16, total_response_size);
411         // log_info("total response size %u", total_response_size);
412         pos += 3;
413         maximumAttributeByteCount -= 3;
414     }
415 
416     // create attribute list
417     int      first_answer = 1;
418     int      continuation = 0;
419     uint16_t current_service_index = 0;
420     btstack_linked_item_t *it = (btstack_linked_item_t *) sdp_service_records;
421     for ( ; it ; it = it->next, ++current_service_index){
422         service_record_item_t * item = (service_record_item_t *) it;
423 
424         if (current_service_index < continuation_service_index ) continue;
425         if (!sdp_record_matches_service_search_pattern(item->service_record, serviceSearchPattern)) continue;
426 
427         if (continuation_offset == 0){
428 
429             // get size of this record
430             uint16_t filtered_attributes_size = spd_get_filtered_size(item->service_record, attributeIDList);
431 
432             // stop if complete record doesn't fits into response but we already have a partial response
433             if (((filtered_attributes_size + 3) > maximumAttributeByteCount) && !first_answer) {
434                 continuation = 1;
435                 break;
436             }
437 
438             // store DES
439             de_store_descriptor_with_len(&sdp_response_buffer[pos], DE_DES, DE_SIZE_VAR_16, filtered_attributes_size);
440             pos += 3;
441             maximumAttributeByteCount -= 3;
442         }
443 
444         first_answer = 0;
445 
446         // copy maximumAttributeByteCount from record
447         uint16_t bytes_used;
448         int complete = sdp_filter_attributes_in_attributeIDList(item->service_record, attributeIDList, continuation_offset, maximumAttributeByteCount, &bytes_used, &sdp_response_buffer[pos]);
449         pos += bytes_used;
450         maximumAttributeByteCount -= bytes_used;
451 
452         if (complete) {
453             continuation_offset = 0;
454             continue;
455         }
456 
457         continuation = 1;
458         continuation_offset += bytes_used;
459         break;
460     }
461 
462     uint16_t attributeListsByteCount = pos - 7;
463 
464     // Continuation State
465     if (continuation){
466         sdp_response_buffer[pos++] = 4;
467         big_endian_store_16(sdp_response_buffer, pos, (uint16_t) current_service_index);
468         pos += 2;
469         big_endian_store_16(sdp_response_buffer, pos, continuation_offset);
470         pos += 2;
471     } else {
472         // complete
473         sdp_response_buffer[pos++] = 0;
474     }
475 
476     // create SDP header
477     sdp_response_buffer[0] = SDP_ServiceSearchAttributeResponse;
478     big_endian_store_16(sdp_response_buffer, 1, transaction_id);
479     big_endian_store_16(sdp_response_buffer, 3, pos - 5);  // size of variable payload
480     big_endian_store_16(sdp_response_buffer, 5, attributeListsByteCount);
481 
482     return pos;
483 }
484 
485 static void sdp_respond(void){
486     if (!sdp_response_size ) return;
487     if (!l2cap_cid) return;
488 
489     // update state before sending packet (avoid getting called when new l2cap credit gets emitted)
490     uint16_t size = sdp_response_size;
491     sdp_response_size = 0;
492     l2cap_send(l2cap_cid, sdp_response_buffer, size);
493 }
494 
495 // @pre space in list
496 static void sdp_waiting_list_add(uint16_t cid){
497     l2cap_waiting_list_cids[l2cap_waiting_list_count++] = cid;
498 }
499 
500 // @pre at least one item in list
501 static uint16_t sdp_waiting_list_get(void){
502     uint16_t cid = l2cap_waiting_list_cids[0];
503     l2cap_waiting_list_count--;
504     if (l2cap_waiting_list_count){
505         memmove(&l2cap_waiting_list_cids[0], &l2cap_waiting_list_cids[1], l2cap_waiting_list_count * sizeof(uint16_t));
506     }
507     return cid;
508 }
509 
510 // we assume that we don't get two requests in a row
511 static void sdp_packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
512 	uint16_t transaction_id;
513     SDP_PDU_ID_t pdu_id;
514     uint16_t remote_mtu;
515     uint16_t param_len;
516 
517 	switch (packet_type) {
518 
519 		case L2CAP_DATA_PACKET:
520             pdu_id = (SDP_PDU_ID_t) packet[0];
521             transaction_id = big_endian_read_16(packet, 1);
522             param_len = big_endian_read_16(packet, 3);
523             remote_mtu = l2cap_get_remote_mtu_for_local_cid(channel);
524             // account for our buffer
525             if (remote_mtu > SDP_RESPONSE_BUFFER_SIZE){
526                 remote_mtu = SDP_RESPONSE_BUFFER_SIZE;
527             }
528             // validate parm_len against packet size
529             if ((param_len + 5) > size) {
530                 // just clear pdu_id
531                 pdu_id = SDP_ErrorResponse;
532             }
533 
534             // log_info("SDP Request: type %u, transaction id %u, len %u, mtu %u", pdu_id, transaction_id, param_len, remote_mtu);
535             switch (pdu_id){
536 
537                 case SDP_ServiceSearchRequest:
538                     sdp_response_size = sdp_handle_service_search_request(packet, remote_mtu);
539                     break;
540 
541                 case SDP_ServiceAttributeRequest:
542                     sdp_response_size = sdp_handle_service_attribute_request(packet, remote_mtu);
543                     break;
544 
545                 case SDP_ServiceSearchAttributeRequest:
546                     sdp_response_size = sdp_handle_service_search_attribute_request(packet, remote_mtu);
547                     break;
548 
549                 default:
550                     sdp_response_size = sdp_create_error_response(transaction_id, 0x0003); // invalid syntax
551                     break;
552             }
553             if (!sdp_response_size) break;
554             l2cap_request_can_send_now_event(l2cap_cid);
555 			break;
556 
557 		case HCI_EVENT_PACKET:
558 
559 			switch (hci_event_packet_get_type(packet)) {
560 
561 				case L2CAP_EVENT_INCOMING_CONNECTION:
562                     if (l2cap_cid) {
563                         // try to queue up
564                         if (l2cap_waiting_list_count < SDP_WAITING_LIST_MAX_COUNT){
565                             sdp_waiting_list_add(channel);
566                             log_info("busy, queing incoming cid 0x%04x, now %u waiting", channel, l2cap_waiting_list_count);
567                             break;
568                         }
569 
570                         // CONNECTION REJECTED DUE TO LIMITED RESOURCES
571                         l2cap_decline_connection(channel);
572                         break;
573                     }
574                     // accept
575                     l2cap_cid = channel;
576                     sdp_response_size = 0;
577                     l2cap_accept_connection(l2cap_cid);
578 					break;
579 
580                 case L2CAP_EVENT_CHANNEL_OPENED:
581                     if (packet[2]) {
582                         // open failed -> reset
583                         l2cap_cid = 0;
584                     }
585                     break;
586 
587                 case L2CAP_EVENT_CAN_SEND_NOW:
588                     sdp_respond();
589                     break;
590 
591                 case L2CAP_EVENT_CHANNEL_CLOSED:
592                     if (channel == l2cap_cid){
593                         // reset
594                         l2cap_cid = 0;
595 
596                         // other request queued?
597                         if (!l2cap_waiting_list_count) break;
598 
599                         // get first item
600                         l2cap_cid = sdp_waiting_list_get();
601 
602                         log_info("disconnect, accept queued cid 0x%04x, now %u waiting", l2cap_cid, l2cap_waiting_list_count);
603 
604                         // accept connection
605                         sdp_response_size = 0;
606                         l2cap_accept_connection(l2cap_cid);
607                     }
608                     break;
609 
610 				default:
611 					// other event
612 					break;
613 			}
614 			break;
615 
616 		default:
617 			// other packet type
618 			break;
619 	}
620 }
621 
622