public static IPAddress getBestRouteTo(IPAddress destIPAddress)
{
sockaddr_inet dest = new sockaddr_inet();
dest.sin_family = (ushort)destIPAddress.AddressFamily;
dest.s_addr = (uint)byteswap(destIPAddress.Address);
dest.sin_zero = 0;
mib_ipforward_row2 bestRoute = new mib_ipforward_row2();
sockaddr_inet bestSrc = new sockaddr_inet();
int res = GetBestRoute2(IntPtr.Zero, 0, IntPtr.Zero, ref dest, 0, ref bestRoute, ref bestSrc);
if (res != 0)
{
throw new Win32Exception(res);
}
return(new IPAddress(bestSrc.s_addr));
}
private static extern int GetBestRoute2(IntPtr InterfaceLUID, int InterfaceIndex, IntPtr SourceAddress,
ref sockaddr_inet destAddress, UInt32 AddresssortOptions, ref mib_ipforward_row2 bestRoute,
ref sockaddr_inet bestSourceAddress);