/// <summary>
/// Retrieves the IPv4 routing table
/// </summary>
/// <param name="forwardTable">The IPv4 routing table</param>
/// <exception cref="OutOfMemoryException">Could not allocate a buffer that can store the routing table</exception>
/// <exception cref="EmptyRouteTableException">There are no routes in the routing table</exception>
/// <exception cref="NotSupportedException">There is no IP stack installed</exception>
/// <exception cref="Win32Exception">Unexpected error</exception>
private static void GetForwardTable(out IpForwardRow[] forwardTable)
{
IntPtr buffer = IntPtr.Zero;
IntPtr bufferSize = IntPtr.Zero;
try
{
var status = NativeLibrary.IPHelper.GetIpForwardTable(buffer, ref bufferSize, false);
if (status == Error.InsufficientBuffer)
{
buffer = Marshal.AllocHGlobal(bufferSize);
status = NativeLibrary.IPHelper.GetIpForwardTable(buffer, ref bufferSize, false);
}
if (status != Error.None)
{
if (buffer != IntPtr.Zero)
{
Marshal.FreeHGlobal(buffer);
}
buffer = IntPtr.Zero;
if (status == Error.NoData)
{
throw new EmptyRouteTableException();
}
if (status == Error.NotSupported)
{
throw new NotSupportedException("There is no IP stack installed on the local computer.");
}
throw new Win32Exception(status);
}
var size = (uint)Marshal.ReadInt32(buffer);
forwardTable = new IpForwardRow[size];
IntPtr currentPointer = buffer + sizeof(uint);
for (int i = 0; i < size; i++)
{
forwardTable[i] = Marshal.PtrToStructure <IpForwardRow>(currentPointer);
currentPointer += Marshal.SizeOf <IpForwardRow>();
}
}
finally
{
if (buffer != IntPtr.Zero)
{
Marshal.FreeHGlobal(buffer);
}
}
}
/// <summary>
/// Retrieves the interface to IP address mapping table.
/// </summary>
/// <returns>A table that describes the mapping between IP addresses and adapters.</returns>
internal static IpForwardRow[] GetIpForwardTable()
{
IpForwardRow[] rows = null;
// figure out how big of a buffer we need
uint size = 0;
int ret = _GetIpForwardTable(IntPtr.Zero, ref size, true);
// Check to see if the call returned a valid result
if (ret != (int)IPErrorCodes.ERROR_SUCCESS &&
ret != (int)IPErrorCodes.ERROR_INSUFFICIENT_BUFFER)
{
Debug.Assert(false, @"Error calling GetIpForwardTable(): " + ret);
return(null);
}
// allocate the ip address table buffer
IntPtr buf = Marshal.AllocHGlobal((int)size);
try
{
// Get the ip address table
ret = _GetIpForwardTable(buf, ref size, true);
// Check to see if the call returned a valid result
if (ret != (int)IPErrorCodes.ERROR_SUCCESS)
{
Debug.Assert(false, @"Error calling GetIpForwardTable(): " + ret);
return(null);
}
// Copy the data into a managed array of IpAddressRow structures
int numEntries = Marshal.ReadInt32(buf);
int pRows = 4 + (int)buf;
rows = new IpForwardRow[(int)numEntries];
for (int i = 0; i < numEntries; i++)
{
rows[i] = (IpForwardRow)Marshal.PtrToStructure((IntPtr)pRows, typeof(IpForwardRow));
pRows += Marshal.SizeOf(typeof(IpForwardRow));
}
}
finally
{
// free the buffer
Marshal.FreeHGlobal(buf);
}
return(rows);
}
internal static extern int DeleteIpForwardEntry(ref IpForwardRow ipForwardRow);
internal static extern int CreateIpForwardEntry(ref IpForwardRow ipForwardRow);
