xref: /btstack/example/gap_inquiry.c (revision a0ffb263e02c613f9155d5035f68cb0ad7b80d74)

/*
 * Copyright (C) 2014 BlueKitchen GmbH
 *
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 * modification, are permitted provided that the following conditions
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 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 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
 *    monetary gain.
 *
 * 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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 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * Please inquire about commercial licensing options at
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// *****************************************************************************
/* EXAMPLE_START(gap_inquiry): GAP Inquiry Example
 *
 * @text The Generic Access Profile (GAP) defines how Bluetooth devices discover
 * and establish a connection with each other. In this example, the application
 * discovers  surrounding Bluetooth devices and collects their Class of Device
 * (CoD), page scan mode, clock offset, and RSSI. After that, the remote name of
 * each device is requested. In the following section we outline the Bluetooth
 * logic part, i.e., how the packet handler handles the asynchronous events and
 * data packets.
 */
// *****************************************************************************

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

#include "btstack.h"

#define MAX_DEVICES 10
enum DEVICE_STATE { REMOTE_NAME_REQUEST, REMOTE_NAME_INQUIRED, REMOTE_NAME_FETCHED };
struct device {
    bd_addr_t  address;
    uint16_t   clockOffset;
    uint32_t   classOfDevice;
    uint8_t    pageScanRepetitionMode;
    uint8_t    rssi;
    enum DEVICE_STATE  state;
};

#define INQUIRY_INTERVAL 5
struct device devices[MAX_DEVICES];
int deviceCount = 0;


enum STATE {INIT, ACTIVE} ;
enum STATE state = INIT;

static btstack_packet_callback_registration_t hci_event_callback_registration;

static int getDeviceIndexForAddress( bd_addr_t addr){
    int j;
    for (j=0; j< deviceCount; j++){
        if (bd_addr_cmp(addr, devices[j].address) == 0){
            return j;
        }
    }
    return -1;
}

static void start_scan(void){
    printf("Starting inquiry scan..\n");
    hci_send_cmd(&hci_inquiry, HCI_INQUIRY_LAP, INQUIRY_INTERVAL, 0);
}

static int has_more_remote_name_requests(void){
    int i;
    for (i=0;i<deviceCount;i++) {
        if (devices[i].state == REMOTE_NAME_REQUEST) return 1;
    }
    return 0;
}

static void do_next_remote_name_request(void){
    int i;
    for (i=0;i<deviceCount;i++) {
        // remote name request
        if (devices[i].state == REMOTE_NAME_REQUEST){
            devices[i].state = REMOTE_NAME_INQUIRED;
            printf("Get remote name of %s...\n", bd_addr_to_str(devices[i].address));
            hci_send_cmd(&hci_remote_name_request, devices[i].address,
                        devices[i].pageScanRepetitionMode, 0, devices[i].clockOffset | 0x8000);
            return;
        }
    }
}

static void continue_remote_names(void){
    if (has_more_remote_name_requests()){
        do_next_remote_name_request();
        return;
    }
    start_scan();
}

/* @section Bluetooth Logic
 *
 * @text The Bluetooth logic is implemented as a state machine within the packet
 * handler. In this example, the following states are passed sequentially:
 * INIT, and ACTIVE.
 */

static void packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){
    bd_addr_t addr;
    int i;
    int numResponses;
    int index;

    if (packet_type != HCI_EVENT_PACKET) return;

    uint8_t event = hci_event_packet_get_type(packet);

    switch(state){
        /* @text In INIT, an inquiry  scan is started, and the application transits to
         * ACTIVE state.
         */
        case INIT:
            switch(event){
                case BTSTACK_EVENT_STATE:
                    if (packet[2] == HCI_STATE_WORKING){
                        start_scan();
                        state = ACTIVE;
                    }
                    break;
                default:
                    break;
            }
            break;

        /* @text In ACTIVE, the following events are processed:
         *  - Inquiry result event: the list of discovered devices is processed and the
         *    Class of Device (CoD), page scan mode, clock offset, and RSSI are stored in a table.
         *  - Inquiry complete event: the remote name is requested for devices without a fetched
         *    name. The state of a remote name can be one of the following:
         *    REMOTE_NAME_REQUEST, REMOTE_NAME_INQUIRED, or REMOTE_NAME_FETCHED.
         *  - Remote name cached event: prints cached remote names provided by BTstack,
         *    if persistent storage is provided.
         *  - Remote name request complete event: the remote name is stored in the table and the
         *    state is updated to REMOTE_NAME_FETCHED. The query of remote names is continued.
         */
        case ACTIVE:
            switch(event){
                case HCI_EVENT_INQUIRY_RESULT:
                case HCI_EVENT_INQUIRY_RESULT_WITH_RSSI:
                    numResponses = packet[2];
                    for (i=0; i<numResponses && deviceCount < MAX_DEVICES;i++){
                        reverse_bd_addr(&packet[3 + i * 6], addr);
                        index = getDeviceIndexForAddress(addr);
                        if (index >= 0) continue;   // already in our list

                        memcpy(devices[deviceCount].address, addr, 6);
                        devices[deviceCount].pageScanRepetitionMode =   packet [3 + numResponses*(6)         + i*1];
                        if (event == HCI_EVENT_INQUIRY_RESULT){
                            devices[deviceCount].classOfDevice = little_endian_read_24(packet, 3 + numResponses*(6+1+1+1)   + i*3);
                            devices[deviceCount].clockOffset =   little_endian_read_16(packet, 3 + numResponses*(6+1+1+1+3) + i*2) & 0x7fff;
                            devices[deviceCount].rssi  = 0;
                        } else {
                            devices[deviceCount].classOfDevice = little_endian_read_24(packet, 3 + numResponses*(6+1+1)     + i*3);
                            devices[deviceCount].clockOffset =   little_endian_read_16(packet, 3 + numResponses*(6+1+1+3)   + i*2) & 0x7fff;
                            devices[deviceCount].rssi  =                    packet [3 + numResponses*(6+1+1+3+2) + i*1];
                        }
                        devices[deviceCount].state = REMOTE_NAME_REQUEST;
                        printf("Device found: %s with COD: 0x%06x, pageScan %d, clock offset 0x%04x, rssi 0x%02x\n", bd_addr_to_str(addr),
                                devices[deviceCount].classOfDevice, devices[deviceCount].pageScanRepetitionMode,
                                devices[deviceCount].clockOffset, devices[deviceCount].rssi);
                        deviceCount++;
                    }
                    break;

                case HCI_EVENT_INQUIRY_COMPLETE:
                    for (i=0;i<deviceCount;i++) {
                        // retry remote name request
                        if (devices[i].state == REMOTE_NAME_INQUIRED)
                            devices[i].state = REMOTE_NAME_REQUEST;
                    }
                    continue_remote_names();
                    break;

                case HCI_EVENT_REMOTE_NAME_REQUEST_COMPLETE:
                    reverse_bd_addr(&packet[3], addr);
                    index = getDeviceIndexForAddress(addr);
                    if (index >= 0) {
                        if (packet[2] == 0) {
                            printf("Name: '%s'\n", &packet[9]);
                            devices[index].state = REMOTE_NAME_FETCHED;
                        } else {
                            printf("Failed to get name: page timeout\n");
                        }
                    }
                    continue_remote_names();
                    break;

                default:
                    break;
            }
            break;

        default:
            break;
    }
}

/* @text For more details on discovering remote devices, please see
 * Section on [GAP](../profiles/#sec:GAPdiscoverRemoteDevices).
 */


/* @section Main Application Setup
 *
 * @text Listing MainConfiguration shows main application code.
 * It registers the HCI packet handler and starts the Bluetooth stack.
 */

/* LISTING_START(MainConfiguration): Setup packet handler for GAP inquiry */
int btstack_main(int argc, const char * argv[]);
int btstack_main(int argc, const char * argv[]) {

    hci_event_callback_registration.callback = &packet_handler;
    hci_add_event_handler(&hci_event_callback_registration);

    // turn on!
    hci_power_control(HCI_POWER_ON);

    return 0;
}
/* LISTING_END */
/* EXAMPLE_END */