xref: /btstack/example/sdp_bnep_query.c (revision bcf00d8fa453bd3a5c441c3b99e6e4b685f0d8f0)
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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     if (packet_type != HCI_EVENT_PACKET) return;
116     uint8_t event = packet[0];
117 
118     switch (event) {
119         case BTSTACK_EVENT_STATE:
120             // BTstack activated, get started
121             if (packet[2] == HCI_STATE_WORKING){
122                 printf("Start SDP BNEP query.\n");
123                 sdp_client_query_uuid16(&handle_sdp_client_query_result, remote, SDP_BNEPProtocol);
124             }
125             break;
126         default:
127             break;
128     }
129 }
130 /* LISTING_END */
131 
132 static char * get_string_from_data_element(uint8_t * element){
133     de_size_t de_size = de_get_size_type(element);
134     int pos     = de_get_header_size(element);
135     int len = 0;
136     switch (de_size){
137         case DE_SIZE_VAR_8:
138             len = element[1];
139             break;
140         case DE_SIZE_VAR_16:
141             len = big_endian_read_16(element, 1);
142             break;
143         default:
144             break;
145     }
146     char * str = (char*)malloc(len+1);
147     memcpy(str, &element[pos], len);
148     str[len] ='\0';
149     return str;
150 }
151 
152 
153 /* @section Handling SDP Client Query Result
154  *
155  * @text The SDP Client returns the result of the query in chunks. Each result
156  * packet contains the record ID, the Attribute ID, and a chunk of the Attribute
157  * value, see Listing HandleSDPQUeryResult. Here, we show how to parse the
158  * Service Class ID List and Protocol Descriptor List, as they contain
159  * the BNEP Protocol UUID and L2CAP PSM respectively.
160  */
161 
162 /* LISTING_START(HandleSDPQUeryResult): Extracting BNEP Protcol UUID and L2CAP PSM */
163 static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
164     /* LISTING_PAUSE */
165     des_iterator_t des_list_it;
166     des_iterator_t prot_it;
167     char *str;
168 
169     switch (packet[0]){
170         case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
171             // handle new record
172             if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id){
173                 record_id = sdp_event_query_attribute_byte_get_record_id(packet);
174                 printf("\n---\nRecord nr. %u\n", record_id);
175             }
176 
177             assertBuffer(sdp_event_query_attribute_byte_get_attribute_length(packet));
178 
179             attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
180             if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)){
181 
182                 /* LISTING_RESUME */
183                 /* @text The Service Class ID List is a Data Element Sequence (DES) of UUIDs.
184                  * The BNEP PAN protocol UUID is within this list.
185                  */
186 
187                 switch(sdp_event_query_attribute_byte_get_attribute_id(packet)){
188                     // 0x0001 "Service Class ID List"
189                     case SDP_ServiceClassIDList:
190                         if (de_get_element_type(attribute_value) != DE_DES) break;
191                         for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
192                             uint8_t * element = des_iterator_get_element(&des_list_it);
193                             if (de_get_element_type(element) != DE_UUID) continue;
194                             uint32_t uuid = de_get_uuid32(element);
195                             switch (uuid){
196                                 case PANU_UUID:
197                                 case NAP_UUID:
198                                 case GN_UUID:
199                                     printf(" ** Attribute 0x%04x: BNEP PAN protocol UUID: %04x\n", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
200                                     break;
201                                 default:
202                                     break;
203                             }
204                         }
205                         break;
206                     /* LISTING_PAUSE */
207                     // 0x0100 "Service Name"
208                     case 0x0100:
209                     // 0x0101 "Service Description"
210                     case 0x0101:
211                         str = get_string_from_data_element(attribute_value);
212                         printf(" ** Attribute 0x%04x: %s\n", sdp_event_query_attribute_byte_get_attribute_id(packet), str);
213                         free(str);
214                         break;
215 
216                     /* LISTING_RESUME */
217                     /* @text The Protocol Descriptor List is DES
218                      * which contains one DES for each protocol. For PAN serivces, it contains
219                      * a DES with the L2CAP Protocol UUID and a PSM,
220                      * and another DES with the BNEP UUID and the the BNEP version.
221                      */
222                     case SDP_ProtocolDescriptorList:{
223                             printf(" ** Attribute 0x%04x: ", sdp_event_query_attribute_byte_get_attribute_id(packet));
224 
225                             uint16_t l2cap_psm = 0;
226                             uint16_t bnep_version = 0;
227                             for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
228                                 if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
229                                 uint8_t * des_element = des_iterator_get_element(&des_list_it);
230                                 des_iterator_init(&prot_it, des_element);
231                                 uint8_t * element = des_iterator_get_element(&prot_it);
232 
233                                 if (de_get_element_type(element) != DE_UUID) continue;
234                                 uint32_t uuid = de_get_uuid32(element);
235                                 switch (uuid){
236                                     case SDP_L2CAPProtocol:
237                                         if (!des_iterator_has_more(&prot_it)) continue;
238                                         des_iterator_next(&prot_it);
239                                         de_element_get_uint16(des_iterator_get_element(&prot_it), &l2cap_psm);
240                                         break;
241                                     case SDP_BNEPProtocol:
242                                         if (!des_iterator_has_more(&prot_it)) continue;
243                                         des_iterator_next(&prot_it);
244                                         de_element_get_uint16(des_iterator_get_element(&prot_it), &bnep_version);
245                                         break;
246                                     default:
247                                         break;
248                                 }
249                             }
250                             printf("l2cap_psm 0x%04x, bnep_version 0x%04x\n", l2cap_psm, bnep_version);
251                         }
252                         break;
253                     /* LISTING_PAUSE */
254                     default:
255                         break;
256                 }
257             }
258             break;
259         case SDP_EVENT_QUERY_COMPLETE:
260             printf("General query done with status %d.\n\n", sdp_event_query_complete_get_status(packet));
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     printf("Client HCI init done\r\n");
270 
271     sdp_client_init();
272 
273     // turn on!
274     hci_power_control(HCI_POWER_ON);
275 
276     return 0;
277 }
278 
279 /* EXAMPLE_END */