xref: /btstack/example/sdp_bnep_query.c (revision 0e2df43f5cbae3fc71139523458b98f30307d21b)

/*
 * Copyright (C) 2014 BlueKitchen GmbH
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 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 * 4. Any redistribution, use, or modification is done solely for
 *    personal benefit and not for any commercial purpose or for
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 *
 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
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// *****************************************************************************
/* EXAMPLE_START(sdp_bnep_query): Dump remote BNEP PAN protocol UUID and L2CAP PSM
 *
 * @text The example shows how the SDP Client is used to get all BNEP service
 * records from a remote device. It extracts the remote BNEP PAN protocol
 * UUID and the L2CAP PSM, which are needed to connect to a remote BNEP service.
 */
// *****************************************************************************

#include "btstack_config.h"

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "btstack_event.h"
#include "btstack_memory.h"
#include "btstack_run_loop.h"
#include "classic/sdp_client.h"
#include "classic/sdp_util.h"
#include "hci.h"
#include "hci_cmd.h"
#include "hci_dump.h"
#include "l2cap.h"
#include "pan.h"

int record_id = -1;
int attribute_id = -1;

static uint8_t   attribute_value[1000];
static const int attribute_value_buffer_size = sizeof(attribute_value);

static bd_addr_t remote = {0x04,0x0C,0xCE,0xE4,0x85,0xD3};
static btstack_packet_callback_registration_t hci_event_callback_registration;

static void assertBuffer(int size){
    if (size > attribute_value_buffer_size){
        printf("SDP attribute value buffer size exceeded: available %d, required %d", attribute_value_buffer_size, size);
    }
}

/* @section SDP Client Setup
 *
 * @text As with the previous example, you must register a
 * callback, i.e. query handler, with the SPD parser, as shown in
 * Listing SDPClientInit. Via this handler, the SDP client will receive events:
 * - SDP_EVENT_QUERY_ATTRIBUTE_VALUE containing the results of the query in chunks,
 * - SDP_EVENT_QUERY_COMPLETE reporting the status and the end of the query.
 */

/* LISTING_START(SDPClientInit): SDP client setup */
static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);
static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size);

static void sdp_client_init(void){

    // register for HCI events
    hci_event_callback_registration.callback = &packet_handler;
    hci_add_event_handler(&hci_event_callback_registration);

    // init L2CAP
    l2cap_init();
}
/* LISTING_END */


/* @section SDP Client Query
 * To trigger an SDP query to get the a list of service records on a remote device,
 * you need to call sdp_client_query_uuid16() with the remote address and the
 * BNEP protocol UUID, as shown in Listing SDPQueryUUID.
 * In this example we again used fixed address of the remote device. Please update
 * for your environment.
 */

/* LISTING_START(SDPQueryUUID): Querying the a list of service records on a remote device. */
static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
    if (packet_type != HCI_EVENT_PACKET) return;
    uint8_t event = hci_event_packet_get_type(packet);

    switch (event) {
        case BTSTACK_EVENT_STATE:
            // BTstack activated, get started
            if (packet[2] == HCI_STATE_WORKING){
                printf("Start SDP BNEP query.\n");
                sdp_client_query_uuid16(&handle_sdp_client_query_result, remote, SDP_BNEPProtocol);
            }
            break;
        default:
            break;
    }
}
/* LISTING_END */

static char * get_string_from_data_element(uint8_t * element){
    de_size_t de_size = de_get_size_type(element);
    int pos     = de_get_header_size(element);
    int len = 0;
    switch (de_size){
        case DE_SIZE_VAR_8:
            len = element[1];
            break;
        case DE_SIZE_VAR_16:
            len = big_endian_read_16(element, 1);
            break;
        default:
            break;
    }
    char * str = (char*)malloc(len+1);
    memcpy(str, &element[pos], len);
    str[len] ='\0';
    return str;
}


/* @section Handling SDP Client Query Result
 *
 * @text The SDP Client returns the result of the query in chunks. Each result
 * packet contains the record ID, the Attribute ID, and a chunk of the Attribute
 * value, see Listing HandleSDPQUeryResult. Here, we show how to parse the
 * Service Class ID List and Protocol Descriptor List, as they contain
 * the BNEP Protocol UUID and L2CAP PSM respectively.
 */

/* LISTING_START(HandleSDPQUeryResult): Extracting BNEP Protcol UUID and L2CAP PSM */
static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
    /* LISTING_PAUSE */
    des_iterator_t des_list_it;
    des_iterator_t prot_it;
    char *str;

    switch (hci_event_packet_get_type(packet)){
        case SDP_EVENT_QUERY_ATTRIBUTE_VALUE:
            // handle new record
            if (sdp_event_query_attribute_byte_get_record_id(packet) != record_id){
                record_id = sdp_event_query_attribute_byte_get_record_id(packet);
                printf("\n---\nRecord nr. %u\n", record_id);
            }

            assertBuffer(sdp_event_query_attribute_byte_get_attribute_length(packet));

            attribute_value[sdp_event_query_attribute_byte_get_data_offset(packet)] = sdp_event_query_attribute_byte_get_data(packet);
            if ((uint16_t)(sdp_event_query_attribute_byte_get_data_offset(packet)+1) == sdp_event_query_attribute_byte_get_attribute_length(packet)){

                /* LISTING_RESUME */
                /* @text The Service Class ID List is a Data Element Sequence (DES) of UUIDs.
                 * The BNEP PAN protocol UUID is within this list.
                 */

                switch(sdp_event_query_attribute_byte_get_attribute_id(packet)){
                    // 0x0001 "Service Class ID List"
                    case SDP_ServiceClassIDList:
                        if (de_get_element_type(attribute_value) != DE_DES) break;
                        for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
                            uint8_t * element = des_iterator_get_element(&des_list_it);
                            if (de_get_element_type(element) != DE_UUID) continue;
                            uint32_t uuid = de_get_uuid32(element);
                            switch (uuid){
                                case PANU_UUID:
                                case NAP_UUID:
                                case GN_UUID:
                                    printf(" ** Attribute 0x%04x: BNEP PAN protocol UUID: %04x\n", sdp_event_query_attribute_byte_get_attribute_id(packet), uuid);
                                    break;
                                default:
                                    break;
                            }
                        }
                        break;
                    /* LISTING_PAUSE */
                    // 0x0100 "Service Name"
                    case 0x0100:
                    // 0x0101 "Service Description"
                    case 0x0101:
                        str = get_string_from_data_element(attribute_value);
                        printf(" ** Attribute 0x%04x: %s\n", sdp_event_query_attribute_byte_get_attribute_id(packet), str);
                        free(str);
                        break;

                    /* LISTING_RESUME */
                    /* @text The Protocol Descriptor List is DES
                     * which contains one DES for each protocol. For PAN serivces, it contains
                     * a DES with the L2CAP Protocol UUID and a PSM,
                     * and another DES with the BNEP UUID and the the BNEP version.
                     */
                    case SDP_ProtocolDescriptorList:{
                            printf(" ** Attribute 0x%04x: ", sdp_event_query_attribute_byte_get_attribute_id(packet));

                            uint16_t l2cap_psm = 0;
                            uint16_t bnep_version = 0;
                            for (des_iterator_init(&des_list_it, attribute_value); des_iterator_has_more(&des_list_it); des_iterator_next(&des_list_it)){
                                if (des_iterator_get_type(&des_list_it) != DE_DES) continue;
                                uint8_t * des_element = des_iterator_get_element(&des_list_it);
                                des_iterator_init(&prot_it, des_element);
                                uint8_t * element = des_iterator_get_element(&prot_it);

                                if (de_get_element_type(element) != DE_UUID) continue;
                                uint32_t uuid = de_get_uuid32(element);
                                switch (uuid){
                                    case SDP_L2CAPProtocol:
                                        if (!des_iterator_has_more(&prot_it)) continue;
                                        des_iterator_next(&prot_it);
                                        de_element_get_uint16(des_iterator_get_element(&prot_it), &l2cap_psm);
                                        break;
                                    case SDP_BNEPProtocol:
                                        if (!des_iterator_has_more(&prot_it)) continue;
                                        des_iterator_next(&prot_it);
                                        de_element_get_uint16(des_iterator_get_element(&prot_it), &bnep_version);
                                        break;
                                    default:
                                        break;
                                }
                            }
                            printf("l2cap_psm 0x%04x, bnep_version 0x%04x\n", l2cap_psm, bnep_version);
                        }
                        break;
                    /* LISTING_PAUSE */
                    default:
                        break;
                }
            }
            break;
        case SDP_EVENT_QUERY_COMPLETE:
            printf("General query done with status %d.\n\n", sdp_event_query_complete_get_status(packet));
            break;
    }
    /* LISTING_RESUME */
}
/* LISTING_END */

int btstack_main(int argc, const char * argv[]);
int btstack_main(int argc, const char * argv[]){
    printf("Client HCI init done\r\n");

    sdp_client_init();

    // turn on!
    hci_power_control(HCI_POWER_ON);

    return 0;
}

/* EXAMPLE_END */