xref: /btstack/example/sdp_bnep_query.c (revision a4fe6467953bdb173fdf96a604f6527ed88f81c3)
1 /*
2  * Copyright (C) 2014 BlueKitchen GmbH
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5  * modification, are permitted provided that the following conditions
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9  *    notice, this list of conditions and the following disclaimer.
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20  * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
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36  */
37 
38 #define __BTSTACK_FILE__ "sdp_bnep_query.c"
39 
40 // *****************************************************************************
41 /* EXAMPLE_START(sdp_bnep_query): Dump remote BNEP PAN protocol UUID and L2CAP PSM
42  *
43  * @text The example shows how the SDP Client is used to get all BNEP service
44  * records from a remote device. It extracts the remote BNEP PAN protocol
45  * UUID and the L2CAP PSM, which are needed to connect to a remote BNEP service.
46  */
47 // *****************************************************************************
48 
49 #include "btstack_config.h"
50 
51 #include <stdint.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 
56 #include "btstack.h"
57 
58 int record_id = -1;
59 int attribute_id = -1;
60 
61 static uint8_t   attribute_value[1000];
62 static const int attribute_value_buffer_size = sizeof(attribute_value);
63 
64 static bd_addr_t remote = {0x04,0x0C,0xCE,0xE4,0x85,0xD3};
65 static btstack_packet_callback_registration_t hci_event_callback_registration;
66 
67 static void assertBuffer(int size){
68     if (size > attribute_value_buffer_size){
69         printf("SDP attribute value buffer size exceeded: available %d, required %d", attribute_value_buffer_size, size);
70     }
71 }
72 
73 /* @section SDP Client Setup
74  *
75  * @text As with the previous example, you must register a
76  * callback, i.e. query handler, with the SPD parser, as shown in
77  * Listing SDPClientInit. Via this handler, the SDP client will receive events:
78  * - SDP_EVENT_QUERY_ATTRIBUTE_VALUE containing the results of the query in chunks,
79  * - SDP_EVENT_QUERY_COMPLETE reporting the status and the end of the query.
80  */
81 
82 /* LISTING_START(SDPClientInit): SDP client setup */
83 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
84 static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
85 
86 static void sdp_client_init(void){
87     // init L2CAP
88     l2cap_init();
89 
90     // register for HCI events
91     hci_event_callback_registration.callback = &packet_handler;
92     hci_add_event_handler(&hci_event_callback_registration);
93 }
94 /* LISTING_END */
95 
96 
97 /* @section SDP Client Query
98  * To trigger an SDP query to get the a list of service records on a remote device,
99  * you need to call sdp_client_query_uuid16() with the remote address and the
100  * BNEP protocol UUID, as shown in Listing SDPQueryUUID.
101  * In this example we again used fixed address of the remote device. Please update
102  * for your environment.
103  */
104 
105 /* LISTING_START(SDPQueryUUID): Querying the a list of service records on a remote device. */
106 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
107     UNUSED(channel);
108     UNUSED(size);
109 
110     if (packet_type != HCI_EVENT_PACKET) return;
111     uint8_t event = hci_event_packet_get_type(packet);
112 
113     switch (event) {
114         case BTSTACK_EVENT_STATE:
115             // BTstack activated, get started
116             if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){
117                 printf("Start SDP BNEP query.\n");
118                 sdp_client_query_uuid16(&handle_sdp_client_query_result, remote, BLUETOOTH_PROTOCOL_BNEP);
119             }
120             break;
121         default:
122             break;
123     }
124 }
125 /* LISTING_END */
126 
127 static char * get_string_from_data_element(uint8_t * element){
128     de_size_t de_size = de_get_size_type(element);
129     int pos     = de_get_header_size(element);
130     int len = 0;
131     switch (de_size){
132         case DE_SIZE_VAR_8:
133             len = element[1];
134             break;
135         case DE_SIZE_VAR_16:
136             len = big_endian_read_16(element, 1);
137             break;
138         default:
139             break;
140     }
141     char * str = (char*)malloc(len+1);
142     memcpy(str, &element[pos], len);
143     str[len] ='\0';
144     return str;
145 }
146 
147 
148 /* @section Handling SDP Client Query Result
149  *
150  * @text The SDP Client returns the result of the query in chunks. Each result
151  * packet contains the record ID, the Attribute ID, and a chunk of the Attribute
152  * value, see Listing HandleSDPQUeryResult. Here, we show how to parse the
153  * Service Class ID List and Protocol Descriptor List, as they contain
154  * the BNEP Protocol UUID and L2CAP PSM respectively.
155  */
156 
157 /* LISTING_START(HandleSDPQUeryResult): Extracting BNEP Protcol UUID and L2CAP PSM */
158 static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
159     UNUSED(packet_type);
160     UNUSED(channel);
161     UNUSED(size);
162 
163     /* LISTING_PAUSE */
164     des_iterator_t des_list_it;
165     des_iterator_t prot_it;
166     char *str;
167 
168     switch (hci_event_packet_get_type(packet)){
169         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
170             // handle new record
171             if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id){
172                 record_id = sdp_event_query_attribute_byte_get_record_id(packet);
173                 printf("\n---\nRecord nr. %u\n", record_id);
174             }
175 
176             assertBuffer(sdp_event_query_attribute_byte_get_attribute_length(packet));
177 
178             attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
179             if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)){
180 
181                 /* LISTING_RESUME */
182                 /* @text The Service Class ID List is a Data Element Sequence (DES) of UUIDs.
183                  * The BNEP PAN protocol UUID is within this list.
184                  */
185 
186                 switch(sdp_event_query_attribute_byte_get_attribute_id(packet)){
187                     // 0x0001 "Service Class ID List"
188                     case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
189                         if (de_get_element_type(attribute_value) != DE_DES) break;
190                         for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
191                             uint8_t * element = des_iterator_get_element(&des_list_it);
192                             if (de_get_element_type(element) != DE_UUID) continue;
193                             uint32_t uuid = de_get_uuid32(element);
194                             switch (uuid){
195                                 case BLUETOOTH_SERVICE_CLASS_PANU:
196                                 case BLUETOOTH_SERVICE_CLASS_NAP:
197                                 case BLUETOOTH_SERVICE_CLASS_GN:
198                                     printf(" ** Attribute 0x%04x: BNEP PAN protocol UUID: %04x\n", sdp_event_query_attribute_byte_get_attribute_id(packet), (int) uuid);
199                                     break;
200                                 default:
201                                     break;
202                             }
203                         }
204                         break;
205                     /* LISTING_PAUSE */
206                     // 0x0100 "Service Name"
207                     case 0x0100:
208                     // 0x0101 "Service Description"
209                     case 0x0101:
210                         str = get_string_from_data_element(attribute_value);
211                         printf(" ** Attribute 0x%04x: %s\n", sdp_event_query_attribute_byte_get_attribute_id(packet), str);
212                         free(str);
213                         break;
214 
215                     /* LISTING_RESUME */
216                     /* @text The Protocol Descriptor List is DES
217                      * which contains one DES for each protocol. For PAN serivces, it contains
218                      * a DES with the L2CAP Protocol UUID and a PSM,
219                      * and another DES with the BNEP UUID and the the BNEP version.
220                      */
221                     case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST:{
222                             printf(" ** Attribute 0x%04x: ", sdp_event_query_attribute_byte_get_attribute_id(packet));
223 
224                             uint16_t l2cap_psm = 0;
225                             uint16_t bnep_version = 0;
226                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
227                                 if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
228                                 uint8_t * des_element = des_iterator_get_element(&des_list_it);
229                                 des_iterator_init(&prot_it, des_element);
230                                 uint8_t * element = des_iterator_get_element(&prot_it);
231 
232                                 if (de_get_element_type(element) != DE_UUID) continue;
233                                 uint32_t uuid = de_get_uuid32(element);
234                                 switch (uuid){
235                                     case BLUETOOTH_PROTOCOL_L2CAP:
236                                         if (!des_iterator_has_more(&prot_it)) continue;
237                                         des_iterator_next(&prot_it);
238                                         de_element_get_uint16(des_iterator_get_element(&prot_it), &l2cap_psm);
239                                         break;
240                                     case BLUETOOTH_PROTOCOL_BNEP:
241                                         if (!des_iterator_has_more(&prot_it)) continue;
242                                         des_iterator_next(&prot_it);
243                                         de_element_get_uint16(des_iterator_get_element(&prot_it), &bnep_version);
244                                         break;
245                                     default:
246                                         break;
247                                 }
248                             }
249                             printf("l2cap_psm 0x%04x, bnep_version 0x%04x\n", l2cap_psm, bnep_version);
250                         }
251                         break;
252                     /* LISTING_PAUSE */
253                     default:
254                         break;
255                 }
256             }
257             break;
258         case SDP_EVENT_QUERY_COMPLETE:
259             if (sdp_event_query_complete_get_status(packet)){
260                 printf("SDP query failed 0x%02x\n", sdp_event_query_complete_get_status(packet));
261                 break;
262             }
263             printf("SDP query done.\n");
264             break;
265     }
266     /* LISTING_RESUME */
267 }
268 /* LISTING_END */
269 
270 int btstack_main(int argc, const char * argv[]);
271 int btstack_main(int argc, const char * argv[]){
272     (void)argc;
273     (void)argv;
274 
275     printf("Client HCI init done\r\n");
276 
277     sdp_client_init();
278 
279     // turn on!
280     hci_power_control(HCI_POWER_ON);
281 
282     return 0;
283 }
284 
285 /* EXAMPLE_END */
286