IPアドレスから、MACアドレスを取得

CString GetMacAddress(LPCTSTR szIPAddress)

{

    CString strResult;

    HRESULT hr = S_OK;

    IPAddr ipAddr = inet_addr(szIPAddress);

    ULONG pulMac[2];

    memset(pulMac, 0xff, sizeof(pulMac));

    ULONG ulLen = 6;

    hr = ::SendARP(ipAddr, 0, pulMac, &ulLen);

    if (FAILED(hr))

    {

        return CString();

    }

// TRACE("Return %08x, length %8d\n", hr, ulLen);

    size_t i, j;

    char* szMac = new char[ulLen * 3];

    PBYTE pbHexMac = (PBYTE)pulMac;

    // Convert the binary MAC address into human-readable

    for (i = 0, j = 0; i < ulLen - 1; ++i)

    {

        j += sprintf (szMac + j, "%02X:", pbHexMac[i]);

    }

    sprintf (szMac + j, "%02X", pbHexMac[i]);

// TRACE ("MAC address %s\n", szMac);

    strResult = szMac;

    delete [] szMac;

    return strResult;

}