xref: /btstack/src/classic/sdp_util.c (revision cfd54eb73cd29e7bf738f261fb454a84a1bb66b0)
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_util.c"
39 
40 /*
41  *  sdp_util.c
42  */
43 
44 #include "bluetooth.h"
45 #include "btstack_config.h"
46 #include "btstack_debug.h"
47 #include "btstack_util.h"
48 #include "classic/core.h"
49 #include "classic/sdp_util.h"
50 
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <stdint.h>
55 #include <inttypes.h>   // PRIx32
56 
57 #ifdef ENABLE_SDP_DES_DUMP
58 // workaround for missing PRIx32 on mspgcc (16-bit MCU)
59 #ifndef PRIx32
60 #warning Using own: #define PRIx32 "lx"
61 #define PRIx32 "lx"
62 #endif
63 // date element type names
64 const char * const type_names[] = { "NIL", "UINT", "INT", "UUID", "STRING", "BOOL", "DES", "DEA", "URL"};
65 #endif
66 
67 static uint8_t des_serviceSearchPatternUUID16[]  = {0x35, 0x03, 0x19, 0x00, 0x00};
68 static uint8_t des_serviceSearchPatternUUID128[] = {
69     0x35, 0x11, 0x1c,
70     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
71     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
72 
73 // MARK: DataElement getter
74 de_size_t de_get_size_type(const uint8_t *header){
75     return (de_size_t) (header[0] & 7);
76 }
77 
78 de_type_t de_get_element_type(const uint8_t *header){
79     return (de_type_t) (header[0] >> 3);
80 }
81 
82 uint32_t de_get_header_size(const uint8_t * header){
83     de_size_t de_size = de_get_size_type(header);
84     if (de_size <= DE_SIZE_128) {
85         return 1;
86     }
87     return 1 + (1 << (de_size-DE_SIZE_VAR_8));
88 }
89 
90 uint32_t de_get_data_size(const uint8_t * header){
91     uint32_t result = 0;
92     de_type_t de_type = de_get_element_type(header);
93     de_size_t de_size = de_get_size_type(header);
94     switch (de_size){
95         case DE_SIZE_VAR_8:
96             result = header[1];
97             break;
98         case DE_SIZE_VAR_16:
99             result = big_endian_read_16(header,1);
100             break;
101         case DE_SIZE_VAR_32:
102             result = big_endian_read_32(header,1);
103             break;
104         default:
105         // case DE_SIZE_8:
106         // case DE_SIZE_16:
107         // case DE_SIZE_32:
108         // case DE_SIZE_64:
109         // case DE_SIZE_128:
110             if (de_type == DE_NIL) return 0;
111             return 1 << de_size;
112     }
113     return result;
114 }
115 
116 int de_get_len(const uint8_t *header){
117     return de_get_header_size(header) + de_get_data_size(header);
118 }
119 
120 // returns data element length if data element fits in size
121 uint32_t de_get_len_safe(const uint8_t * header, uint32_t size){
122     if (1           > size) return 0;
123     uint32_t header_size = de_get_header_size(header);
124     if (header_size > size) return 0;
125     uint32_t data_size   = de_get_data_size(header);
126     if (data_size   > size) return 0;
127     uint32_t de_len      = header_size + data_size;
128     if (de_len      > size) return 0;
129     return de_len;
130 }
131 
132 // @returns OK, if UINT16 value was read
133 int de_element_get_uint16(const uint8_t * element, uint16_t * value){
134     if (de_get_size_type(element) != DE_SIZE_16) return 0;
135     *value = big_endian_read_16(element, de_get_header_size(element));
136     return 1;
137 }
138 
139 // @returns: element is valid UUID
140 int de_get_normalized_uuid(uint8_t *uuid128, const uint8_t *element){
141     de_type_t uuidType = de_get_element_type(element);
142     de_size_t uuidSize = de_get_size_type(element);
143     if (uuidType != DE_UUID) return 0;
144     uint32_t shortUUID;
145     switch (uuidSize){
146         case DE_SIZE_16:
147             shortUUID = big_endian_read_16(element, 1);
148             break;
149         case DE_SIZE_32:
150             shortUUID = big_endian_read_32(element, 1);
151             break;
152         case DE_SIZE_128:
153             (void)memcpy(uuid128, element + 1, 16);
154             return 1;
155         default:
156             return 0;
157     }
158     uuid_add_bluetooth_prefix(uuid128, shortUUID);
159     return 1;
160 }
161 
162 // @returns 0 if no UUID16 or UUID32 is present, and UUID32 otherwise
163 uint32_t de_get_uuid32(const uint8_t * element){
164     uint8_t uuid128[16];
165     int validUuid128 = de_get_normalized_uuid(uuid128, element);
166     if (!validUuid128) return 0;
167     int hasBlueoothBaseUuid = uuid_has_bluetooth_prefix(uuid128);
168     if (!hasBlueoothBaseUuid) return 0;
169     return big_endian_read_32(uuid128, 0);
170 }
171 
172 const uint8_t * de_get_string(const uint8_t * element){
173     if (de_get_element_type(element) != DE_STRING) return NULL;
174     return &element[de_get_header_size(element)];
175 }
176 
177 // functions to create record
178 static void de_store_descriptor(uint8_t * header, de_type_t type, de_size_t size){
179     header[0] = (type << 3) | size;
180 }
181 
182 void de_store_descriptor_with_len(uint8_t * header, de_type_t type, de_size_t size, uint32_t len){
183     header[0] = (type << 3) | size;
184     switch (size){
185         case DE_SIZE_VAR_8:
186             header[1] = len;
187             break;
188         case DE_SIZE_VAR_16:
189             big_endian_store_16(header, 1, len);
190             break;
191         case DE_SIZE_VAR_32:
192             big_endian_store_32(header, 1, len);
193             break;
194         default:
195             break;
196     }
197 }
198 
199 // MARK: DataElement creation
200 
201 /* starts a new sequence in empty buffer - first call */
202 void de_create_sequence(uint8_t *header){
203     de_store_descriptor_with_len( header, DE_DES, DE_SIZE_VAR_16, 0); // DES, 2 Byte Length
204 };
205 
206 /* starts a sub-sequence, @returns handle for sub-sequence */
207 uint8_t * de_push_sequence(uint8_t *header){
208     int element_len = de_get_len(header);
209     de_store_descriptor_with_len(header+element_len, DE_DES, DE_SIZE_VAR_16, 0); // DES, 2 Byte Length
210     return header + element_len;
211 }
212 
213 /* closes the current sequence and updates the parent sequence */
214 void de_pop_sequence(uint8_t * parent, uint8_t * child){
215     int child_len = de_get_len(child);
216     int data_size_parent = big_endian_read_16(parent,1);
217     big_endian_store_16(parent, 1, data_size_parent + child_len);
218 }
219 
220 /* adds a single number value and 16+32 bit UUID to the sequence */
221 void de_add_number(uint8_t *seq, de_type_t type, de_size_t size, uint32_t value){
222     int data_size   = big_endian_read_16(seq,1);
223     int element_size = 1;   // e.g. for DE_TYPE_NIL
224     de_store_descriptor(seq+3+data_size, type, size);
225     switch (size){
226         case DE_SIZE_8:
227             if (type != DE_NIL){
228                 seq[4+data_size] = value;
229                 element_size = 2;
230             }
231             break;
232         case DE_SIZE_16:
233             big_endian_store_16(seq, 4+data_size, value);
234             element_size = 3;
235             break;
236         case DE_SIZE_32:
237             big_endian_store_32(seq, 4+data_size, value);
238             element_size = 5;
239             break;
240         default:
241             break;
242     }
243     big_endian_store_16(seq, 1, data_size+element_size);
244 }
245 
246 /* add a single block of data, e.g. as DE_STRING, DE_URL */
247 void de_add_data( uint8_t *seq, de_type_t type, uint16_t size, uint8_t *data){
248     int data_size   = big_endian_read_16(seq,1);
249     if (size > 0xff) {
250         // use 16-bit lengh information (3 byte header)
251         de_store_descriptor_with_len(seq+3+data_size, type, DE_SIZE_VAR_16, size);
252         data_size += 3;
253     } else {
254         // use 8-bit lengh information (2 byte header)
255         de_store_descriptor_with_len(seq+3+data_size, type, DE_SIZE_VAR_8, size);
256         data_size += 2;
257     }
258     if (size > 0){
259 		(void)memcpy(seq + 3 + data_size, data, size);
260 		data_size += size;
261     }
262     big_endian_store_16(seq, 1, data_size);
263 }
264 
265 void de_add_uuid128(uint8_t * seq, uint8_t * uuid){
266     int data_size   = big_endian_read_16(seq,1);
267     de_store_descriptor(seq+3+data_size, DE_UUID, DE_SIZE_128);
268     (void)memcpy(seq + 4 + data_size, uuid, 16);
269     big_endian_store_16(seq, 1, data_size+1+16);
270 }
271 
272 // MARK: DES iterator
273 bool des_iterator_init(des_iterator_t * it, uint8_t * element){
274     de_type_t type = de_get_element_type(element);
275     if (type != DE_DES) return false;
276 
277     it->element = element;
278     it->pos = de_get_header_size(element);
279     it->length = de_get_len(element);
280     // printf("des_iterator_init current pos %d, total len %d\n", it->pos, it->length);
281     return true;
282 }
283 
284 de_type_t des_iterator_get_type (des_iterator_t * it){
285     return de_get_element_type(&it->element[it->pos]);
286 }
287 
288 uint16_t des_iterator_get_size (des_iterator_t * it){
289     int length = de_get_len(&it->element[it->pos]);
290     int header_size = de_get_header_size(&it->element[it->pos]);
291     return length - header_size;
292 }
293 
294 bool des_iterator_has_more(des_iterator_t * it){
295     return it->pos < it->length;
296 }
297 
298 uint8_t * des_iterator_get_element(des_iterator_t * it){
299     if (!des_iterator_has_more(it)) return NULL;
300     return &it->element[it->pos];
301 }
302 
303 void des_iterator_next(des_iterator_t * it){
304     int element_len = de_get_len(&it->element[it->pos]);
305     // printf("des_iterator_next element size %d, current pos %d, total len %d\n", element_len, it->pos, it->length);
306     it->pos += element_len;
307 }
308 
309 // MARK: DataElementSequence traversal
310 typedef int (*de_traversal_callback_t)(uint8_t * element, de_type_t type, de_size_t size, void *context);
311 static void de_traverse_sequence(uint8_t * element, de_traversal_callback_t handler, void *context){
312     de_type_t type = de_get_element_type(element);
313     if (type != DE_DES) return;
314     int pos = de_get_header_size(element);
315     int end_pos = de_get_len(element);
316     while (pos < end_pos){
317         de_type_t elemType = de_get_element_type(element + pos);
318         de_size_t elemSize = de_get_size_type(element + pos);
319         uint8_t done = (*handler)(element + pos, elemType, elemSize, context);
320         if (done) break;
321         pos += de_get_len(element + pos);
322     }
323 }
324 
325 // MARK: AttributeList traversal
326 typedef int (*sdp_attribute_list_traversal_callback_t)(uint16_t attributeID, uint8_t * attributeValue, de_type_t type, de_size_t size, void *context);
327 static void sdp_attribute_list_traverse_sequence(uint8_t * element, sdp_attribute_list_traversal_callback_t handler, void *context){
328     de_type_t type = de_get_element_type(element);
329     if (type != DE_DES) return;
330     int pos = de_get_header_size(element);
331     int end_pos = de_get_len(element);
332     while (pos < end_pos){
333         de_type_t idType = de_get_element_type(element + pos);
334         de_size_t idSize = de_get_size_type(element + pos);
335         if ( (idType != DE_UINT) || (idSize != DE_SIZE_16) ) break; // wrong type
336         uint16_t attribute_id = big_endian_read_16(element, pos + 1);
337         pos += 3;
338         if (pos >= end_pos) break; // array out of bounds
339         de_type_t valueType = de_get_element_type(element + pos);
340         de_size_t valueSize = de_get_size_type(element + pos);
341         uint8_t done = (*handler)(attribute_id, element + pos, valueType, valueSize, context);
342         if (done) break;
343         pos += de_get_len(element + pos);
344     }
345 }
346 
347 // MARK: AttributeID in AttributeIDList
348 // attribute ID in AttributeIDList
349 // context { result, attributeID }
350 struct sdp_context_attributeID_search {
351     int result;
352     uint16_t attributeID;
353 };
354 static int sdp_traversal_attributeID_search(uint8_t * element, de_type_t type, de_size_t size, void *my_context){
355     struct sdp_context_attributeID_search * context = (struct sdp_context_attributeID_search *) my_context;
356     if (type != DE_UINT) return 0;
357     switch (size) {
358         case DE_SIZE_16:
359             if (big_endian_read_16(element, 1) == context->attributeID) {
360                 context->result = 1;
361                 return 1;
362             }
363             break;
364         case DE_SIZE_32:
365             if ((big_endian_read_16(element, 1) <= context->attributeID)
366             &&  (context->attributeID <= big_endian_read_16(element, 3))) {
367                 context->result = 1;
368                 return 1;
369             }
370             break;
371         default:
372             break;
373     }
374     return 0;
375 }
376 
377 int sdp_attribute_list_constains_id(uint8_t *attributeIDList, uint16_t attributeID){
378     struct sdp_context_attributeID_search attributeID_search;
379     attributeID_search.result = 0;
380     attributeID_search.attributeID = attributeID;
381     de_traverse_sequence(attributeIDList, sdp_traversal_attributeID_search, &attributeID_search);
382     return attributeID_search.result;
383 }
384 
385 // MARK: Append Attributes for AttributeIDList
386 // pre: buffer contains DES with 2 byte length field
387 struct sdp_context_append_attributes {
388     uint8_t * buffer;
389     uint16_t startOffset;     // offset of when to start copying
390     uint16_t maxBytes;
391     uint16_t usedBytes;
392     uint8_t *attributeIDList;
393 };
394 
395 static int sdp_traversal_append_attributes(uint16_t attributeID, uint8_t * attributeValue, de_type_t de_type, de_size_t de_size, void *my_context){
396     UNUSED(de_type);
397     UNUSED(de_size);
398     struct sdp_context_append_attributes * context = (struct sdp_context_append_attributes *) my_context;
399     if (sdp_attribute_list_constains_id(context->attributeIDList, attributeID)) {
400         // DES_HEADER(3) + DES_DATA + (UINT16(3) + attribute)
401         uint16_t data_size = big_endian_read_16(context->buffer, 1);
402         int attribute_len = de_get_len(attributeValue);
403         if ((3 + data_size + (3 + attribute_len)) <= context->maxBytes) {
404             // copy Attribute
405             de_add_number(context->buffer, DE_UINT, DE_SIZE_16, attributeID);
406             data_size += 3; // 3 bytes
407             (void)memcpy(context->buffer + 3 + data_size, attributeValue,
408                          attribute_len);
409             big_endian_store_16(context->buffer,1,data_size+attribute_len);
410         } else {
411             // not enought space left -> continue with previous element
412             return 1;
413         }
414     }
415     return 0;
416 }
417 
418 // maxBytes: maximal size of data element sequence
419 uint16_t sdp_append_attributes_in_attributeIDList(uint8_t *record, uint8_t *attributeIDList, uint16_t startOffset, uint16_t maxBytes, uint8_t *buffer){
420     struct sdp_context_append_attributes context;
421     context.buffer = buffer;
422     context.maxBytes = maxBytes;
423     context.usedBytes = 0;
424     context.startOffset = startOffset;
425     context.attributeIDList = attributeIDList;
426     sdp_attribute_list_traverse_sequence(record, sdp_traversal_append_attributes, &context);
427     return context.usedBytes;
428 }
429 
430 // MARK: Filter attributes that match attribute list from startOffset and a max nr bytes
431 struct sdp_context_filter_attributes {
432     uint8_t * buffer;
433     uint16_t startOffset;     // offset of when to start copying
434     uint16_t maxBytes;
435     uint16_t usedBytes;
436     uint8_t *attributeIDList;
437     int      complete;
438 };
439 
440 // copy data with given start offset and max bytes, returns OK if all data has been copied
441 static int spd_append_range(struct sdp_context_filter_attributes* context, uint16_t len, uint8_t *data){
442     int ok = 1;
443     uint16_t remainder_len = len - context->startOffset;
444     if (context->maxBytes < remainder_len){
445         remainder_len = context->maxBytes;
446         ok = 0;
447     }
448     (void)memcpy(context->buffer, &data[context->startOffset], remainder_len);
449     context->usedBytes += remainder_len;
450     context->buffer    += remainder_len;
451     context->maxBytes  -= remainder_len;
452     context->startOffset = 0;
453     return ok;
454 }
455 
456 static int sdp_traversal_filter_attributes(uint16_t attributeID, uint8_t * attributeValue, de_type_t de_type, de_size_t de_size, void *my_context){
457     UNUSED(de_type);
458     UNUSED(de_size);
459 
460     struct sdp_context_filter_attributes * context = (struct sdp_context_filter_attributes *) my_context;
461 
462     if (!sdp_attribute_list_constains_id(context->attributeIDList, attributeID)) return 0;
463 
464     // { Attribute ID (Descriptor, big endian 16-bit ID), AttributeValue (data)}
465 
466     // handle Attribute ID
467     if (context->startOffset >= 3){
468         context->startOffset -= 3;
469     } else {
470         uint8_t idBuffer[3];
471         de_store_descriptor(idBuffer, DE_UINT,  DE_SIZE_16);
472         big_endian_store_16(idBuffer,1,attributeID);
473 
474         int ok = spd_append_range(context, 3, idBuffer);
475         if (!ok) {
476             context->complete = 0;
477             return 1;
478         }
479     }
480 
481     // handle Attribute Value
482     int attribute_len = de_get_len(attributeValue);
483     if (context->startOffset >= attribute_len) {
484         context->startOffset -= attribute_len;
485         return 0;
486     }
487 
488     int ok = spd_append_range(context, attribute_len, attributeValue);
489     if (!ok) {
490         context->complete = 0;
491         return 1;
492     }
493     return 0;
494 }
495 
496 int sdp_filter_attributes_in_attributeIDList(uint8_t *record, uint8_t *attributeIDList, uint16_t startOffset, uint16_t maxBytes, uint16_t *usedBytes, uint8_t *buffer){
497 
498     struct sdp_context_filter_attributes context;
499     context.buffer = buffer;
500     context.maxBytes = maxBytes;
501     context.usedBytes = 0;
502     context.startOffset = startOffset;
503     context.attributeIDList = attributeIDList;
504     context.complete = 1;
505 
506     sdp_attribute_list_traverse_sequence(record, sdp_traversal_filter_attributes, &context);
507 
508     *usedBytes = context.usedBytes;
509     return context.complete;
510 }
511 
512 // MARK: Get sum of attributes matching attribute list
513 struct sdp_context_get_filtered_size {
514     uint8_t *attributeIDList;
515     uint16_t size;
516 };
517 
518 static int sdp_traversal_get_filtered_size(uint16_t attributeID, uint8_t * attributeValue, de_type_t de_type, de_size_t de_size, void *my_context){
519     UNUSED(de_type);
520     UNUSED(de_size);
521 
522     struct sdp_context_get_filtered_size * context = (struct sdp_context_get_filtered_size *) my_context;
523     if (sdp_attribute_list_constains_id(context->attributeIDList, attributeID)) {
524         context->size += 3 + de_get_len(attributeValue);
525     }
526     return 0;
527 }
528 
529 int spd_get_filtered_size(uint8_t *record, uint8_t *attributeIDList){
530     struct sdp_context_get_filtered_size context;
531     context.size = 0;
532     context.attributeIDList = attributeIDList;
533     sdp_attribute_list_traverse_sequence(record, sdp_traversal_get_filtered_size, &context);
534     return context.size;
535 }
536 
537 // MARK: Get AttributeValue for AttributeID
538 // find attribute (ELEMENT) by ID
539 struct sdp_context_attribute_by_id {
540     uint16_t  attributeID;
541     uint8_t * attributeValue;
542 };
543 static int sdp_traversal_attribute_by_id(uint16_t attributeID, uint8_t * attributeValue, de_type_t de_type, de_size_t de_size, void *my_context){
544     UNUSED(de_type);
545     UNUSED(de_size);
546 
547     struct sdp_context_attribute_by_id * context = (struct sdp_context_attribute_by_id *) my_context;
548     if (attributeID == context->attributeID) {
549         context->attributeValue = attributeValue;
550         return 1;
551     }
552     return 0;
553 }
554 
555 uint8_t * sdp_get_attribute_value_for_attribute_id(uint8_t * record, uint16_t attributeID){
556     struct sdp_context_attribute_by_id context;
557     context.attributeValue = NULL;
558     context.attributeID = attributeID;
559     sdp_attribute_list_traverse_sequence(record, sdp_traversal_attribute_by_id, &context);
560     return context.attributeValue;
561 }
562 
563 // MARK: Set AttributeValue for AttributeID
564 struct sdp_context_set_attribute_for_id {
565     uint16_t  attributeID;
566     uint32_t  attributeValue;
567     uint8_t   attributeFound;
568 };
569 static int sdp_traversal_set_attribute_for_id(uint16_t attributeID, uint8_t * attributeValue, de_type_t attributeType, de_size_t size, void *my_context){
570     struct sdp_context_set_attribute_for_id * context = (struct sdp_context_set_attribute_for_id *) my_context;
571     if (attributeID == context->attributeID) {
572         context->attributeFound = 1;
573         switch (size){
574             case DE_SIZE_8:
575                 if (attributeType != DE_NIL){
576                     attributeValue[1] = context->attributeValue;
577                 }
578                 break;
579             case DE_SIZE_16:
580                 big_endian_store_16(attributeValue, 1, context->attributeValue);
581                 break;
582             case DE_SIZE_32:
583                 big_endian_store_32(attributeValue, 1, context->attributeValue);
584                 break;
585                 // Might want to support STRINGS to, copy upto original length
586             default:
587                 break;
588         }
589         return 1;
590     }
591     return 0;
592 }
593 uint8_t sdp_set_attribute_value_for_attribute_id(uint8_t * record, uint16_t attributeID, uint32_t value){
594     struct sdp_context_set_attribute_for_id context;
595     context.attributeID = attributeID;
596     context.attributeValue = value;
597     context.attributeFound = 0;
598     sdp_attribute_list_traverse_sequence(record, sdp_traversal_set_attribute_for_id, &context);
599     return context.attributeFound;
600 }
601 
602 // MARK: ServiceRecord contains UUID
603 // service record contains UUID
604 // context { normalizedUUID }
605 struct sdp_context_contains_uuid128 {
606     uint8_t * uuid128;
607     int result;
608 };
609 int sdp_record_contains_UUID128(uint8_t *record, uint8_t *uuid128);
610 static int sdp_traversal_contains_UUID128(uint8_t * element, de_type_t type, de_size_t de_size, void *my_context){
611     UNUSED(de_size);
612 
613     struct sdp_context_contains_uuid128 * context = (struct sdp_context_contains_uuid128 *) my_context;
614     uint8_t normalizedUUID[16];
615     if (type == DE_UUID){
616         uint8_t uuidOK = de_get_normalized_uuid(normalizedUUID, element);
617         context->result = uuidOK && (memcmp(context->uuid128, normalizedUUID, 16) == 0);
618     }
619     if (type == DE_DES){
620         context->result = sdp_record_contains_UUID128(element, context->uuid128);
621     }
622     return context->result;
623 }
624 int sdp_record_contains_UUID128(uint8_t *record, uint8_t *uuid128){
625     struct sdp_context_contains_uuid128 context;
626     context.uuid128 = uuid128;
627     context.result = 0;
628     de_traverse_sequence(record, sdp_traversal_contains_UUID128, &context);
629     return context.result;
630 }
631 
632 // MARK: ServiceRecord matches SearchServicePattern
633 // if UUID in searchServicePattern is not found in record => false
634 // context { result, record }
635 struct sdp_context_match_pattern {
636     uint8_t * record;
637     int result;
638 };
639 
640 int sdp_traversal_match_pattern(uint8_t * element, de_type_t de_type, de_size_t de_size, void *my_context){
641     UNUSED(de_type);
642     UNUSED(de_size);
643 
644     struct sdp_context_match_pattern * context = (struct sdp_context_match_pattern *) my_context;
645     uint8_t normalizedUUID[16];
646     uint8_t uuidOK = de_get_normalized_uuid(normalizedUUID, element);
647     if (!uuidOK || !sdp_record_contains_UUID128(context->record, normalizedUUID)){
648         context->result = 0;
649         return 1;
650     }
651     return 0;
652 }
653 int sdp_record_matches_service_search_pattern(uint8_t *record, uint8_t *serviceSearchPattern){
654     struct sdp_context_match_pattern context;
655     context.record = record;
656     context.result = 1;
657     de_traverse_sequence(serviceSearchPattern, sdp_traversal_match_pattern, &context);
658     return context.result;
659 }
660 
661 // MARK: Dump DataElement
662 // context { indent }
663 #ifdef ENABLE_SDP_DES_DUMP
664 static int de_traversal_dump_data(uint8_t * element, de_type_t de_type, de_size_t de_size, void *my_context){
665     int indent = *(int*) my_context;
666     int i;
667     for (i=0; i<indent;i++) printf("    ");
668     unsigned int pos     = de_get_header_size(element);
669     unsigned int end_pos = de_get_len(element);
670     printf("type %5s (%u), element len %2u ", type_names[de_type], de_type, end_pos);
671     if (de_type == DE_DES) {
672 		printf("\n");
673         indent++;
674         de_traverse_sequence(element, de_traversal_dump_data, (void *)&indent);
675     } else if (de_type == DE_UUID && de_size == DE_SIZE_128) {
676         printf(", value: %s\n", uuid128_to_str(element+1));
677     } else if (de_type == DE_STRING) {
678         unsigned int len = 0;
679         switch (de_size){
680             case DE_SIZE_VAR_8:
681                 len = element[1];
682                 break;
683             case DE_SIZE_VAR_16:
684                 len = big_endian_read_16(element, 1);
685                 break;
686             default:
687                 break;
688         }
689         printf("len %u (0x%02x)\n", len, len);
690         printf_hexdump(&element[pos], len);
691     } else {
692         uint32_t value = 0;
693         switch (de_size) {
694             case DE_SIZE_8:
695                 if (de_type != DE_NIL){
696                     value = element[pos];
697                 }
698                 break;
699             case DE_SIZE_16:
700 				value = big_endian_read_16(element,pos);
701                 break;
702             case DE_SIZE_32:
703 				value = big_endian_read_32(element,pos);
704                 break;
705             default:
706                 break;
707         }
708         printf(", value: 0x%08" PRIx32 "\n", value);
709     }
710     return 0;
711 }
712 #endif
713 
714 void de_dump_data_element(const uint8_t * record){
715 #ifdef ENABLE_SDP_DES_DUMP
716     int indent = 0;
717     // hack to get root DES, too.
718     de_type_t type = de_get_element_type(record);
719     de_size_t size = de_get_size_type(record);
720     de_traversal_dump_data((uint8_t *) record, type, size, (void*) &indent);
721 #endif
722 }
723 
724 uint8_t* sdp_service_search_pattern_for_uuid16(uint16_t uuid16){
725     big_endian_store_16(des_serviceSearchPatternUUID16, 3, uuid16);
726     return (uint8_t*)des_serviceSearchPatternUUID16;
727 }
728 
729 uint8_t* sdp_service_search_pattern_for_uuid128(const uint8_t * uuid128){
730     (void)memcpy(&des_serviceSearchPatternUUID128[3], uuid128, 16);
731     return (uint8_t*)des_serviceSearchPatternUUID128;
732 }
733 
734