xref: /btstack/example/sdp_bnep_query.c (revision 13820c00dabb68537de1aad3faa3d32f07eecff1)
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37 
38 #define BTSTACK_FILE__ "sdp_bnep_query.c"
39 
40 // *****************************************************************************
41 /* EXAMPLE_START(sdp_bnep_query): SDP Records - Dump BNEP PAN protocol
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 void get_string_from_data_element(uint8_t * element, uint16_t buffer_size, char * buffer_data){
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     uint16_t bytes_to_copy = btstack_min(buffer_size-1,len);
142     memcpy(buffer_data, &element[pos], bytes_to_copy);
143     buffer_data[bytes_to_copy] ='\0';
144 }
145 
146 
147 /* @section Handling SDP Client Query Result
148  *
149  * @text The SDP Client returns the result of the query in chunks. Each result
150  * packet contains the record ID, the Attribute ID, and a chunk of the Attribute
151  * value, see Listing HandleSDPQUeryResult. Here, we show how to parse the
152  * Service Class ID List and Protocol Descriptor List, as they contain
153  * the BNEP Protocol UUID and L2CAP PSM respectively.
154  */
155 
156 /* LISTING_START(HandleSDPQUeryResult): Extracting BNEP Protcol UUID and L2CAP PSM */
157 static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
158     UNUSED(packet_type);
159     UNUSED(channel);
160     UNUSED(size);
161 
162     /* LISTING_PAUSE */
163     des_iterator_t des_list_it;
164     des_iterator_t prot_it;
165     char str[20];
166 
167     switch (hci_event_packet_get_type(packet)){
168         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
169             // handle new record
170             if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id){
171                 record_id = sdp_event_query_attribute_byte_get_record_id(packet);
172                 printf("\n---\nRecord nr. %u\n", record_id);
173             }
174 
175             assertBuffer(sdp_event_query_attribute_byte_get_attribute_length(packet));
176 
177             attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
178             if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)){
179 
180                 /* LISTING_RESUME */
181                 /* @text The Service Class ID List is a Data Element Sequence (DES) of UUIDs.
182                  * The BNEP PAN protocol UUID is within this list.
183                  */
184 
185                 switch(sdp_event_query_attribute_byte_get_attribute_id(packet)){
186                     // 0x0001 "Service Class ID List"
187                     case BLUETOOTH_ATTRIBUTE_SERVICE_CLASS_ID_LIST:
188                         if (de_get_element_type(attribute_value) != DE_DES) break;
189                         for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
190                             uint8_t * element = des_iterator_get_element(&des_list_it);
191                             if (de_get_element_type(element) != DE_UUID) continue;
192                             uint32_t uuid = de_get_uuid32(element);
193                             switch (uuid){
194                                 case BLUETOOTH_SERVICE_CLASS_PANU:
195                                 case BLUETOOTH_SERVICE_CLASS_NAP:
196                                 case BLUETOOTH_SERVICE_CLASS_GN:
197                                     printf(" ** Attribute 0x%04x: BNEP PAN protocol UUID: %04x\n", sdp_event_query_attribute_byte_get_attribute_id(packet), (int) uuid);
198                                     break;
199                                 default:
200                                     break;
201                             }
202                         }
203                         break;
204                     /* LISTING_PAUSE */
205                     // 0x0100 "Service Name"
206                     case 0x0100:
207                     // 0x0101 "Service Description"
208                     case 0x0101:
209                         get_string_from_data_element(attribute_value, sizeof(str), str);
210                         printf(" ** Attribute 0x%04x: %s\n", sdp_event_query_attribute_byte_get_attribute_id(packet), str);
211                         break;
212 
213                     /* LISTING_RESUME */
214                     /* @text The Protocol Descriptor List is DES
215                      * which contains one DES for each protocol. For PAN serivces, it contains
216                      * a DES with the L2CAP Protocol UUID and a PSM,
217                      * and another DES with the BNEP UUID and the the BNEP version.
218                      */
219                     case BLUETOOTH_ATTRIBUTE_PROTOCOL_DESCRIPTOR_LIST:{
220                             printf(" ** Attribute 0x%04x: ", sdp_event_query_attribute_byte_get_attribute_id(packet));
221 
222                             uint16_t l2cap_psm = 0;
223                             uint16_t bnep_version = 0;
224                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
225                                 if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
226                                 uint8_t * des_element = des_iterator_get_element(&des_list_it);
227                                 des_iterator_init(&prot_it, des_element);
228                                 uint8_t * element = des_iterator_get_element(&prot_it);
229 
230                                 if (de_get_element_type(element) != DE_UUID) continue;
231                                 uint32_t uuid = de_get_uuid32(element);
232                                 des_iterator_next(&prot_it);
233                                 switch (uuid){
234                                     case BLUETOOTH_PROTOCOL_L2CAP:
235                                         if (!des_iterator_has_more(&prot_it)) continue;
236                                         de_element_get_uint16(des_iterator_get_element(&prot_it), &l2cap_psm);
237                                         break;
238                                     case BLUETOOTH_PROTOCOL_BNEP:
239                                         if (!des_iterator_has_more(&prot_it)) continue;
240                                         de_element_get_uint16(des_iterator_get_element(&prot_it), &bnep_version);
241                                         break;
242                                     default:
243                                         break;
244                                 }
245                             }
246                             printf("l2cap_psm 0x%04x, bnep_version 0x%04x\n", l2cap_psm, bnep_version);
247                         }
248                         break;
249                     /* LISTING_PAUSE */
250                     default:
251                         break;
252                 }
253             }
254             break;
255         case SDP_EVENT_QUERY_COMPLETE:
256             if (sdp_event_query_complete_get_status(packet)){
257                 printf("SDP query failed 0x%02x\n", sdp_event_query_complete_get_status(packet));
258                 break;
259             }
260             printf("SDP query done.\n");
261             break;
262     }
263     /* LISTING_RESUME */
264 }
265 /* LISTING_END */
266 
267 int btstack_main(int argc, const char * argv[]);
268 int btstack_main(int argc, const char * argv[]){
269     (void)argc;
270     (void)argv;
271 
272     printf("Client HCI init done\r\n");
273 
274     sdp_client_init();
275 
276     // turn on!
277     hci_power_control(HCI_POWER_ON);
278 
279     return 0;
280 }
281 
282 /* EXAMPLE_END */
283