IpReleaseAddress (iphlpapi)
Last changed: anonymous

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Summary
TODO - a short description

C# Signature:

    [DllImport("Iphlpapi.dll", CharSet = CharSet.Auto)]
    public static extern int IpReleaseAddress(ref IP_ADAPTER_INDEX_MAP AdapterInfo);

User-Defined Types:

None.

Alternative Managed API:

Do you know one? Please contribute it!

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

The following C# sourcecode implements classes and structures with the purpose of making the use of GetInterfaceInfo and IpReleaseAddress easier. Thanks to Lieutenant (http://www.red-gate.com/MessageBoard/viewtopic.php?t=5754) for submitting this code.

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public struct IP_ADAPTER_INDEX_MAP
    {
    public int Index;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = PInvokes.MAX_ADAPTER_NAME)]
    public String Name;
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public struct IP_INTERFACE_INFO
    {
    public int NumAdapters;
    public IP_ADAPTER_INDEX_MAP[] Adapter;

    public static IP_INTERFACE_INFO FromByteArray(Byte[] buffer)
    {
    unsafe
    {
        IP_INTERFACE_INFO rv = new IP_INTERFACE_INFO();
        int iNumAdapters = 0;
        Marshal.Copy(buffer, 0, new IntPtr(&iNumAdapters), 4);
        IP_ADAPTER_INDEX_MAP[] adapters = new IP_ADAPTER_INDEX_MAP[iNumAdapters];
        rv.NumAdapters = iNumAdapters;
        rv.Adapter = new IP_ADAPTER_INDEX_MAP[iNumAdapters];
        int offset = sizeof(int);
        for (int i = 0; i < iNumAdapters; i++)
        {
        IP_ADAPTER_INDEX_MAP map = new IP_ADAPTER_INDEX_MAP();
        IntPtr ptr = Marshal.AllocHGlobal(Marshal.SizeOf(map));
        Marshal.StructureToPtr(map, ptr, false);
        Marshal.Copy(buffer, offset, ptr, Marshal.SizeOf(map));
        map = (IP_ADAPTER_INDEX_MAP)Marshal.PtrToStructure(ptr, typeof(IP_ADAPTER_INDEX_MAP));
        Marshal.FreeHGlobal(ptr);
        rv.Adapter[i] = map;
        offset += Marshal.SizeOf(map);
        }
        return rv;
     }
    }
    }

    internal class PInvokes
    {
    public const int MAX_ADAPTER_NAME = 128;

    public const int ERROR_INSUFFICIENT_BUFFER = 122;
    public const int ERROR_SUCCESS = 0;

    [DllImport("Iphlpapi.dll", CharSet = CharSet.Auto)]
    public static extern int GetInterfaceInfo(Byte[] PIfTableBuffer, ref int size);

    [DllImport("Iphlpapi.dll", CharSet = CharSet.Auto)]
    public static extern int IpReleaseAddress(ref IP_ADAPTER_INDEX_MAP AdapterInfo);
    }

    public class Iphlpapi
    {
    public static IP_INTERFACE_INFO GetInterfaceInfo()
    {
    int size = 0;
    int r = PInvokes.GetInterfaceInfo(null, ref size);
    Byte[] buffer = new Byte[size];
    r = PInvokes.GetInterfaceInfo(buffer, ref size);
    if (r != PInvokes.ERROR_SUCCESS)
        throw new Exception("GetInterfaceInfo returned an error.");
    IP_INTERFACE_INFO info = IP_INTERFACE_INFO.FromByteArray(buffer);
    return info;
    }

    public static bool IpReleaseAddress(IP_ADAPTER_INDEX_MAP adapter)
    {
    if (PInvokes.IpReleaseAddress(ref adapter) == PInvokes.ERROR_SUCCESS)
        return true;
    else
        return false;
    }

    public static void IpReleaseAllAddresses()
    {
    IP_INTERFACE_INFO info = GetInterfaceInfo();
    for (int i = 0; i < info.NumAdapters; i++)
        IpReleaseAddress(info.Adapter[i]);
    }
    }

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