#include <winsock2.h>
#include <ws2tcpip.h>

#include <iphlpapi.h>

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

int main()
{
    // Declare and initialize variables.

    DWORD dwSize = 0;
    DWORD dwRetVal = 0;

    int i, j;

    /* variables used for GetIfTable and GetIfEntry */
    MIB_IFTABLE *pIfTable;
    MIB_IFROW *pIfRow;

    // Allocate memory for our pointers.
    pIfTable = (MIB_IFTABLE *) malloc(sizeof (MIB_IFTABLE));
    if (pIfTable == NULL) {
        printf("Error allocating memory needed to call GetIfTable\n");
        return 1;
    }
    // Make an initial call to GetIfTable to get the
    // necessary size into dwSize
    dwSize = sizeof (MIB_IFTABLE);
    if (GetIfTable(pIfTable, &dwSize, FALSE) == ERROR_INSUFFICIENT_BUFFER) {
        free(pIfTable);
        pIfTable = (MIB_IFTABLE *) malloc(dwSize);
        if (pIfTable == NULL) {
            printf("Error allocating memory needed to call GetIfTable\n");
            return 1;
        }
    }
    // Make a second call to GetIfTable to get the actual
    // data we want.
    if ((dwRetVal = GetIfTable(pIfTable, &dwSize, FALSE)) == NO_ERROR) {
        printf("\tNum Entries: %ld\n\n", pIfTable->dwNumEntries);
        for (i = 0; i < (int) pIfTable->dwNumEntries; i++) {
            pIfRow = (MIB_IFROW *) & pIfTable->table[i];
            printf("\tIndex[%d]:\t %ld\n", i, pIfRow->dwIndex);
            printf("\tInterfaceName[%d]:\t %S", i, pIfRow->wszName);
            printf("\n");
            printf("\tDescription[%d]:\t ", i);
            for (j = 0; j < (int) pIfRow->dwDescrLen; j++)
                printf("%c", pIfRow->bDescr[j]);
            printf("\n");
            printf("\tType[%d]:\t ", i);
            switch (pIfRow->dwType) {
            case MIB_IF_TYPE_OTHER:
                printf("Other\n");
                break;
            case MIB_IF_TYPE_ETHERNET:
                printf("Ethernet\n");
                break;
            case MIB_IF_TYPE_TOKENRING:
                printf("Token Ring\n");
                break;
            case MIB_IF_TYPE_PPP:
                printf("PPP\n");
                break;
            case MIB_IF_TYPE_LOOPBACK:
                printf("Software Lookback\n");
                break;
            default:
                printf("Unknown type %ld\n", pIfRow->dwType);
                break;
            }
            printf("\tMtu[%d]:\t\t %ld\n", i, pIfRow->dwMtu);
            printf("\tSpeed[%d]:\t %ld\n", i, pIfRow->dwSpeed);
            printf("\tPhysical Addr:\t ");
            if (pIfRow->dwPhysAddrLen == 0)
                printf("\n");
            for (j = 0; j < (int) pIfRow->dwPhysAddrLen; j++) {
                if (j == (pIfRow->dwPhysAddrLen - 1))
                    printf("%.2X\n", (int) pIfRow->bPhysAddr[j]);
                else
                    printf("%.2X-", (int) pIfRow->bPhysAddr[j]);
            }
            printf("\tAdmin Status[%d]:\t %ld\n", i, pIfRow->dwAdminStatus);
            printf("\tOper Status[%d]:\t ", i);
            switch (pIfRow->dwOperStatus) {
            case MIB_IF_OPER_STATUS_NON_OPERATIONAL:
                printf("Non Operational\n");
                break;
            case MIB_IF_OPER_STATUS_UNREACHABLE:
                printf("Unreachable\n");
                break;
            case MIB_IF_OPER_STATUS_DISCONNECTED:
                printf("Disconnected\n");
                break;
            case MIB_IF_OPER_STATUS_CONNECTING:
                printf("Connecting\n");
                break;
            case MIB_IF_OPER_STATUS_CONNECTED:
                printf("Connected\n");
                break;
            case MIB_IF_OPER_STATUS_OPERATIONAL:
                printf("Operational\n");
                break;
            default:
                printf("Unknown status %ld\n", pIfRow->dwAdminStatus);
                break;
            }
            printf("\n");
        }
    } else {
        printf("GetIfTable failed with error: \n", dwRetVal);
        if (pIfTable != NULL) {
            free(pIfTable);
            pIfTable = NULL;
        }  
        return 1;
        // Here you can use FormatMessage to find out why 
        // it failed.
    }
    if (pIfTable != NULL) {
        free(pIfTable);
        pIfTable = NULL;
    }
    return 0;
}