xref: /btstack/example/sdp_bnep_query.c (revision 1a6822024624aab466a9aff5f67325f81ed6d5e2)
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37 
38 // *****************************************************************************
39 /* EXAMPLE_START(sdp_bnep_query): Dump remote BNEP PAN protocol UUID and L2CAP PSM
40  *
41  * @text The example shows how the SDP Client is used to get all BNEP service
42  * records from a remote device. It extracts the remote BNEP PAN protocol
43  * UUID and the L2CAP PSM, which are needed to connect to a remote BNEP service.
44  */
45 // *****************************************************************************
46 
47 #include "btstack_config.h"
48 
49 #include <stdint.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 
54 #include "btstack_event.h"
55 #include "btstack_memory.h"
56 #include "btstack_run_loop.h"
57 #include "classic/sdp_client.h"
58 #include "classic/sdp_util.h"
59 #include "hci.h"
60 #include "hci_cmd.h"
61 #include "hci_dump.h"
62 #include "l2cap.h"
63 #include "pan.h"
64 
65 int record_id = -1;
66 int attribute_id = -1;
67 
68 static uint8_t   attribute_value[1000];
69 static const int attribute_value_buffer_size = sizeof(attribute_value);
70 
71 static bd_addr_t remote = {0x04,0x0C,0xCE,0xE4,0x85,0xD3};
72 static btstack_packet_callback_registration_t hci_event_callback_registration;
73 
74 static void assertBuffer(int size){
75     if (size > attribute_value_buffer_size){
76         printf("SDP attribute value buffer size exceeded: available %d, required %d", attribute_value_buffer_size, size);
77     }
78 }
79 
80 /* @section SDP Client Setup
81  *
82  * @text As with the previous example, you must register a
83  * callback, i.e. query handler, with the SPD parser, as shown in
84  * Listing SDPClientInit. Via this handler, the SDP client will receive events:
85  * - SDP_EVENT_QUERY_ATTRIBUTE_VALUE containing the results of the query in chunks,
86  * - SDP_EVENT_QUERY_COMPLETE reporting the status and the end of the query.
87  */
88 
89 /* LISTING_START(SDPClientInit): SDP client setup */
90 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
91 static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
92 
93 static void sdp_client_init(void){
94 
95     // register for HCI events
96     hci_event_callback_registration.callback = &packet_handler;
97     hci_add_event_handler(&hci_event_callback_registration);
98 
99     // init L2CAP
100     l2cap_init();
101 }
102 /* LISTING_END */
103 
104 
105 /* @section SDP Client Query
106  * To trigger an SDP query to get the a list of service records on a remote device,
107  * you need to call sdp_client_query_uuid16() with the remote address and the
108  * BNEP protocol UUID, as shown in Listing SDPQueryUUID.
109  * In this example we again used fixed address of the remote device. Please update
110  * for your environment.
111  */
112 
113 /* LISTING_START(SDPQueryUUID): Querying the a list of service records on a remote device. */
114 static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
115     UNUSED(channel);
116     UNUSED(size);
117 
118     if (packet_type != HCI_EVENT_PACKET) return;
119     uint8_t event = hci_event_packet_get_type(packet);
120 
121     switch (event) {
122         case BTSTACK_EVENT_STATE:
123             // BTstack activated, get started
124             if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){
125                 printf("Start SDP BNEP query.\n");
126                 sdp_client_query_uuid16(&handle_sdp_client_query_result, remote, SDP_BNEPProtocol);
127             }
128             break;
129         default:
130             break;
131     }
132 }
133 /* LISTING_END */
134 
135 static char * get_string_from_data_element(uint8_t * element){
136     de_size_t de_size = de_get_size_type(element);
137     int pos     = de_get_header_size(element);
138     int len = 0;
139     switch (de_size){
140         case DE_SIZE_VAR_8:
141             len = element[1];
142             break;
143         case DE_SIZE_VAR_16:
144             len = big_endian_read_16(element, 1);
145             break;
146         default:
147             break;
148     }
149     char * str = (char*)malloc(len+1);
150     memcpy(str, &element[pos], len);
151     str[len] ='\0';
152     return str;
153 }
154 
155 
156 /* @section Handling SDP Client Query Result
157  *
158  * @text The SDP Client returns the result of the query in chunks. Each result
159  * packet contains the record ID, the Attribute ID, and a chunk of the Attribute
160  * value, see Listing HandleSDPQUeryResult. Here, we show how to parse the
161  * Service Class ID List and Protocol Descriptor List, as they contain
162  * the BNEP Protocol UUID and L2CAP PSM respectively.
163  */
164 
165 /* LISTING_START(HandleSDPQUeryResult): Extracting BNEP Protcol UUID and L2CAP PSM */
166 static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
167     UNUSED(packet_type);
168     UNUSED(channel);
169     UNUSED(size);
170 
171     /* LISTING_PAUSE */
172     des_iterator_t des_list_it;
173     des_iterator_t prot_it;
174     char *str;
175 
176     switch (hci_event_packet_get_type(packet)){
177         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
178             // handle new record
179             if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id){
180                 record_id = sdp_event_query_attribute_byte_get_record_id(packet);
181                 printf("\n---\nRecord nr. %u\n", record_id);
182             }
183 
184             assertBuffer(sdp_event_query_attribute_byte_get_attribute_length(packet));
185 
186             attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
187             if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)){
188 
189                 /* LISTING_RESUME */
190                 /* @text The Service Class ID List is a Data Element Sequence (DES) of UUIDs.
191                  * The BNEP PAN protocol UUID is within this list.
192                  */
193 
194                 switch(sdp_event_query_attribute_byte_get_attribute_id(packet)){
195                     // 0x0001 "Service Class ID List"
196                     case SDP_ServiceClassIDList:
197                         if (de_get_element_type(attribute_value) != DE_DES) break;
198                         for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
199                             uint8_t * element = des_iterator_get_element(&des_list_it);
200                             if (de_get_element_type(element) != DE_UUID) continue;
201                             uint32_t uuid = de_get_uuid32(element);
202                             switch (uuid){
203                                 case PANU_UUID:
204                                 case NAP_UUID:
205                                 case GN_UUID:
206                                     printf(" ** Attribute 0x%04x: BNEP PAN protocol UUID: %04x\n", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
207                                     break;
208                                 default:
209                                     break;
210                             }
211                         }
212                         break;
213                     /* LISTING_PAUSE */
214                     // 0x0100 "Service Name"
215                     case 0x0100:
216                     // 0x0101 "Service Description"
217                     case 0x0101:
218                         str = get_string_from_data_element(attribute_value);
219                         printf(" ** Attribute 0x%04x: %s\n", sdp_event_query_attribute_byte_get_attribute_id(packet), str);
220                         free(str);
221                         break;
222 
223                     /* LISTING_RESUME */
224                     /* @text The Protocol Descriptor List is DES
225                      * which contains one DES for each protocol. For PAN serivces, it contains
226                      * a DES with the L2CAP Protocol UUID and a PSM,
227                      * and another DES with the BNEP UUID and the the BNEP version.
228                      */
229                     case SDP_ProtocolDescriptorList:{
230                             printf(" ** Attribute 0x%04x: ", sdp_event_query_attribute_byte_get_attribute_id(packet));
231 
232                             uint16_t l2cap_psm = 0;
233                             uint16_t bnep_version = 0;
234                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
235                                 if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
236                                 uint8_t * des_element = des_iterator_get_element(&des_list_it);
237                                 des_iterator_init(&prot_it, des_element);
238                                 uint8_t * element = des_iterator_get_element(&prot_it);
239 
240                                 if (de_get_element_type(element) != DE_UUID) continue;
241                                 uint32_t uuid = de_get_uuid32(element);
242                                 switch (uuid){
243                                     case SDP_L2CAPProtocol:
244                                         if (!des_iterator_has_more(&prot_it)) continue;
245                                         des_iterator_next(&prot_it);
246                                         de_element_get_uint16(des_iterator_get_element(&prot_it), &l2cap_psm);
247                                         break;
248                                     case SDP_BNEPProtocol:
249                                         if (!des_iterator_has_more(&prot_it)) continue;
250                                         des_iterator_next(&prot_it);
251                                         de_element_get_uint16(des_iterator_get_element(&prot_it), &bnep_version);
252                                         break;
253                                     default:
254                                         break;
255                                 }
256                             }
257                             printf("l2cap_psm 0x%04x, bnep_version 0x%04x\n", l2cap_psm, bnep_version);
258                         }
259                         break;
260                     /* LISTING_PAUSE */
261                     default:
262                         break;
263                 }
264             }
265             break;
266         case SDP_EVENT_QUERY_COMPLETE:
267             printf("General query done with status %d.\n\n", sdp_event_query_complete_get_status(packet));
268             break;
269     }
270     /* LISTING_RESUME */
271 }
272 /* LISTING_END */
273 
274 int btstack_main(int argc, const char * argv[]);
275 int btstack_main(int argc, const char * argv[]){
276     (void)argc;
277     (void)argv;
278 
279     printf("Client HCI init done\r\n");
280 
281     sdp_client_init();
282 
283     // turn on!
284     hci_power_control(HCI_POWER_ON);
285 
286     return 0;
287 }
288 
289 /* EXAMPLE_END */