xref: /btstack/example/sdp_general_query.c (revision bcf00d8fa453bd3a5c441c3b99e6e4b685f0d8f0)

/*
 * Copyright (C) 2014 BlueKitchen GmbH
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 * modification, are permitted provided that the following conditions
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 *
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 *    notice, this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer in the
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 * 3. Neither the name of the copyright holders nor the names of
 *    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
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
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 * Please inquire about commercial licensing options at
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// *****************************************************************************
/* EXAMPLE_START(sdp_general_query): Dump remote SDP Records
 *
 * @text The example shows how the SDP Client is used to get a list of
 * service records on a remote device.
 */
// *****************************************************************************

#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"

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 btstack_packet_callback_registration_t hci_event_callback_registration;

/* @section SDP Client Setup
 *
 * @text SDP is based on L2CAP. To receive SDP query events 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 the following events:
 * - SDP_EVENT_QUERY_ATTRIBUTE_VALUE containing the results of the query in chunks,
 * - SDP_EVENT_QUERY_COMPLETE indicating the end of the query and the status
 */

/* 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
 *
 * @text 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
 * UUID of the public browse group, as shown in Listing SDPQueryUUID.
 * In this example we used fixed address of the remote device shown in Listing Remote.
 * Please update it with the address of a device in your vicinity, e.g., one reported
 * by the GAP Inquiry example in the previous section.
 */

/* LISTING_START(Remote): Address of remote device in big-endian order */
static bd_addr_t remote = {0x04,0x0C,0xCE,0xE4,0x85,0xD3};
/* LISTING_END */

/* LISTING_START(SDPQueryUUID): Querying 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){
    // printf("packet_handler type %u, packet[0] %x\n", packet_type, packet[0]);

    if (packet_type != HCI_EVENT_PACKET) return;
    uint8_t event = packet[0];

    switch (event) {
        case BTSTACK_EVENT_STATE:
            if (packet[2] == HCI_STATE_WORKING){
                sdp_client_query_uuid16(&handle_sdp_client_query_result, remote, SDP_PublicBrowseGroup);
            }
            break;
        default:
            break;
    }
}
/* LISTING_END */

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 Handling SDP Client Query Results
 *
 * @text The SDP Client returns the results of the query in chunks. Each result
 * packet contains the record ID, the Attribute ID, and a chunk of the Attribute
 * value.
 * In this example, we append new chunks for the same Attribute ID in a large buffer,
 * see Listing HandleSDPQUeryResult.
 *
 * To save memory, it's also possible to process these chunks directly by a custom stream parser,
 * similar to the way XML files are parsed by a SAX parser. Have a look at *src/sdp_query_rfcomm.c*
 * which retrieves the RFCOMM channel number and the service name.
 */

/* LISTING_START(HandleSDPQUeryResult): Handling query result chunks. */
static void handle_sdp_client_query_result(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
    switch (packet[0]){
        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)){
               printf("Attribute 0x%04x: ", sdp_event_query_attribute_byte_get_attribute_id(packet));
               de_dump_data_element(attribute_value);
            }
            break;
        case SDP_EVENT_QUERY_COMPLETE:
            printf("General query done with status %d.\n\n", sdp_event_query_complete_get_status(packet));
            exit(0);
            break;
    }
}
/* 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 */