02_adapter_change_notifier.c

This example shows how to register and handle adapter change notifications. It will print each received notification to command line. Each output will also include the change reason and the new adapter property value.

Attention

This example requires a valid bRAWcap license. Reading adapter properties is not part of the demo.

/**
 * @file 02_adapter_change_notifier.c
 *
 * @brief bRAWcap Example - Demonstrates the usage of the adapter handling module.
 *
 * It shows how to:
 *   - Receive adapter change notifications
 *   - Process change notifications
 *
 * This example makes use of C only.
 *
 * @attention This example requires a valid bRAWcap license.
 * Receiving adapter change notifications and reading their properties is not part of the demo.
 *
 * @version 1.0
 *
 * @date 2023-03-24
 *
 * @copyright
 * <b> © 2021 - b-plus technologies GmbH. All rights reserved!</b>
 *
 * All rights exclusively reserved for b-plus GmbH, unless expressly otherwise agreed.
 *
 * Redistribution in source or any other form, with or without modification, is not permitted.
 *
 * You may use this code under the according license terms of b-plus.
 * Please contact b-plus at services@b-plus.com to get the appropriate terms and conditions.
 */
// Include bRAWcap
#include "libbrawcap.h"
 
// C STD
#include <stdlib.h> // for malloc & free
#include <stdio.h>  // for printf
 
// Check command line parameters if a custom execution time is specified
void ParseArgs(int argc, char** argv, int* exec_time)
{
    if(argc > 1)
    {
        if(!memcmp(argv[1], "-t", 2))
        {
            char* pEnd = 0;
            *exec_time = strtol(argv[2], &pEnd,0);
        }
    }
}
 
void change_notification_callback(const brawcap_adapter_name_t name, const brawcap_adapter_notify_reason_t reason,
                                  const UINT32 properties, void* pUser)
{
    // We have entered a user context which points to a notification counter.
    // To use it we should first of all check if it is valid and if so cast it to the correct type.
    if(pUser)
    {
        brawcap_status_t status = BRAWCAP_STATUS_SUCCESS;
        int* pNotifyCounter = (int*) pUser;
        ++(*pNotifyCounter);
 
#if 1   // We always try to print the friendly name too (for readability...)
        // Therefore we must retrieve it from the adapter name.
        // If an adapter is not available anymore we can not resolve it´s friendly name.
        // In this case it will be "null" instead.
        char* friendlyName = 0;
        UINT32 friendlyNameLength = 0;
        if(brawcap_adapter_friendly_name(name, friendlyName, &friendlyNameLength) == BRAWCAP_STATUS_ERROR_OVERRUN)
        {
            friendlyName = malloc(friendlyNameLength);
            status = brawcap_adapter_friendly_name(name, friendlyName, &friendlyNameLength);
            if(status != BRAWCAP_STATUS_SUCCESS)
            {
                printf("Could not resolve adapter friendly name (unexpected status: %d)\n", status);
                free(friendlyName);
                return;
            }
        }
#endif
        printf("\n%03d. Notification\n", *pNotifyCounter);
#if 1   // Now handle the different notification reasons.
        switch (reason)
        {
#if 1   // The given reason is unknown
        case BRAWCAP_ADAPTER_NOTIFY_REASON_UNKNOWN:
        default:
            printf("Unknown notification reason.");
            break;
#endif
#if 1   // The specified adapter was added
        case BRAWCAP_ADAPTER_NOTIFY_REASON_ADD:
            printf("%s (%s) added\n", friendlyName, name);
            break;
#endif
#if 1   // The specified adapter was removed
        case BRAWCAP_ADAPTER_NOTIFY_REASON_REMOVE:
            printf("%s (%s) removed\n", friendlyName, name);
            break;
#endif
#if 1   // At least one property of the specified adapter has changed.
        case BRAWCAP_ADAPTER_NOTIFY_REASON_PROPERTY_CHANGE:
#if 1       // Connection state has changed
            if(properties & BRAWCAP_ADAPTER_PROPERTY_CONNECTION_STATE)
            {
                brawcap_adapter_connection_state_t connectionState = BRAWCAP_ADAPTER_CONNECTION_UNKNOWN;
                brawcap_adapter_connection(name, &connectionState);
                printf("%s (%s) new connection state: ", friendlyName, name);
                switch (connectionState)
                {
                case BRAWCAP_ADAPTER_CONNECTION_UNKNOWN: printf("%s\n", "Unknown"); break;
                case BRAWCAP_ADAPTER_CONNECTION_DOWN:    printf("%s\n", "Down");    break;
                case BRAWCAP_ADAPTER_CONNECTION_UP:      printf("%s\n", "Up");      break;
                }
            }
#endif
#if 1       // Friendly name has changed
            if(properties & BRAWCAP_ADAPTER_PROPERTY_FRIENDLY_NAME)
                printf("%s new friendly name: %s\n", name, friendlyName);
#endif
#if 1       // IPv4 has changed
            if(properties & BRAWCAP_ADAPTER_PROPERTY_IPV4)
            {
                brawcap_adapter_ipv4_t ipv4 = {0};
                brawcap_adapter_ipv4(name, &ipv4);
                printf("%s (%s) new IPv4: %u.%u.%u.%u\n", friendlyName, name,
                       ipv4.bytes[0], ipv4.bytes[1], ipv4.bytes[2], ipv4.bytes[3]);
            }
#endif
#if 1       // IPv6 has changed
            if(properties & BRAWCAP_ADAPTER_PROPERTY_IPV6)
            {
                brawcap_adapter_ipv6_t ipv6 = {0};
                brawcap_adapter_ipv6(name, &ipv6);
                printf("%s (%s) new IPv6: %x:%x:%x:%x:%x:%x:%x:%x\n", friendlyName, name,
                       ipv6.words[0], ipv6.words[1], ipv6.words[2], ipv6.words[3],
                       ipv6.words[4], ipv6.words[5], ipv6.words[6], ipv6.words[7]);
            }
#endif
#if 1       // Max transmission unit has changed
            if(properties & BRAWCAP_ADAPTER_PROPERTY_MTU)
            {
                brawcap_adapter_mtu_t mtu = 0;
                brawcap_adapter_mtu(name, &mtu);
                printf("%s (%s) new max transmission unit: %llu\n", friendlyName, name, mtu);
            }
#endif
#if 1       // Operation state has changed
            if(properties & BRAWCAP_ADAPTER_PROPERTY_OPERATION_STATE)
            {
                brawcap_adapter_operation_state_t operationState = BRAWCAP_ADAPTER_OPERATION_UNKNOWN;
                brawcap_adapter_operation(name, &operationState);
                printf("%s (%s) new operation state: ", friendlyName, name);
                switch (operationState)
                {
                case BRAWCAP_ADAPTER_OPERATION_UNKNOWN: printf("%s\n", "Unknown"); break;
                case BRAWCAP_ADAPTER_OPERATION_DOWN:    printf("%s\n", "Down");    break;
                case BRAWCAP_ADAPTER_OPERATION_TESTING: printf("%s\n", "Testing"); break;
                case BRAWCAP_ADAPTER_OPERATION_UP:      printf("%s\n", "Up");      break;
                }
            }
#endif
#if 1       // Receive speed has changed
            if(properties & BRAWCAP_ADAPTER_PROPERTY_RX_SPEED)
            {
                brawcap_adapter_speed_t speed = BRAWCAP_ADAPTER_SPEED_UNKNOWN;
                brawcap_adapter_speed_rx(name, &speed);
                printf("%s (%s) new receive (uplink) speed: %u MBit/s\n", friendlyName, name, speed);
            }
#endif
#if 1       // Transmit speed has changed
            if(properties & BRAWCAP_ADAPTER_PROPERTY_TX_SPEED)
            {
                brawcap_adapter_speed_t speed = BRAWCAP_ADAPTER_SPEED_UNKNOWN;
                brawcap_adapter_speed_tx(name, &speed);
                printf("%s (%s) new transmit (uplink) speed: %u MBit/s\n", friendlyName, name, speed);
            }
#endif
            break;
#endif
        }
        // Don´t forget to free the allocated memory...
        free(friendlyName);
    }
#endif
}
 
// Use command line parameter -t to specify a custom execution time.
// If it is not given the execution time is per default 5 minutes.
int main(int argc, char** argv)
{
    // Set console title
    SetConsoleTitleA("bRAWcap Example - Adapter Change Notifier");
 
    int exec_time = 300; // 5 minutes
    int runtime_sec = 0;
    ParseArgs(argc, argv, &exec_time);
 
    brawcap_status_t status = BRAWCAP_STATUS_SUCCESS;
 
    // This variable will be entered during registration, to make it available from inside the callback.
    // ATTENTION: You are responsible for checking the pointer inside your callback, before accessing it.
    int notifyCounter = 0;
 
    // Register our process for bRAWcap adapter change notifications
    brawcap_adapter_notify_callback_t callback = change_notification_callback;
    status = brawcap_adapter_notify_register(callback, &notifyCounter);
    if(!BRAWCAP_SUCCESS(status))
    {
        printf("Registration for adapter change notification failed (Status: %d). Will stop now...", status);
        return -1;
    }
 
    // Our main thread does nothing than waiting until execution time is elapsed.
    // Everything else is done by the thread which is calling our registered callback.
    do
    {
        Sleep(1000);
    } while (++runtime_sec < exec_time);
 
    // Unregister bRAWcap adapter change notifications before exiting.
    // NOTE: bRAWcap would automatically unregister on unloading.
    //       Therefore unregistering on exiting isn´t required...
    status = brawcap_adapter_notify_unregister();
    if(!BRAWCAP_SUCCESS(status))
    {
        printf("Unregistration for adapter change noTification failed (Status: %d). Will stop now...", status);
        return -1;
    }
 
    return 0;
}