btstack/example/embedded/sdp_general_query.c

/*
 * 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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 *    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_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 "sdp_parser.h"
#include "sdp_client.h"
#include "sdp_query_util.h"

#include "hci_cmds.h"
#include "run_loop.h"

#include "hci.h"
#include "btstack_memory.h"
#include "hci_dump.h"
#include "l2cap.h"
#include "sdp_parser.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);

/* @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_QUERY_ATTRIBUTE_VALUE containing the results of the query in chunks,
 * - SDP_QUERY_COMPLETE indicating the end of the query and the status
 */

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

static void sdp_client_init(void){
    // init L2CAP
    l2cap_init();
    l2cap_register_packet_handler(packet_handler);

    sdp_parser_init();
    sdp_parser_register_callback(handle_sdp_client_query_result);
}
/* 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_general_query_for_uuid() 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 (void * connection, 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_general_query_for_uuid(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(sdp_query_event_t * event){
    sdp_query_attribute_value_event_t * ve;
    sdp_query_complete_event_t * ce;

    switch (event->type){
        case SDP_QUERY_ATTRIBUTE_VALUE:
            ve = (sdp_query_attribute_value_event_t*) event;
            
            // handle new record
            if (ve->record_id != record_id){
                record_id = ve->record_id;
                printf("\n---\nRecord nr. %u\n", record_id);
            }

            assertBuffer(ve->attribute_length);

            attribute_value[ve->data_offset] = ve->data;
            if ((uint16_t)(ve->data_offset+1) == ve->attribute_length){
               printf("Attribute 0x%04x: ", ve->attribute_id);
               de_dump_data_element(attribute_value);
            }
            break;
        case SDP_QUERY_COMPLETE:
            ce = (sdp_query_complete_event_t*) event;
            printf("General query done with status %d.\n\n", ce->status);
            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 */