public bool Receive()
{
//Buffer pointer
IntPtr bufferPtr = Marshal.AllocHGlobal(NativeConstants.WinDivertMaxBuffer);
byte[] bufferArr = new byte[NativeConstants.WinDivertMaxBuffer];
//Adderss pointer
WINDIVERT_ADDRESS pAddress = new WINDIVERT_ADDRESS();
IntPtr pAddressPtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(WINDIVERT_ADDRESS)));
Marshal.StructureToPtr(pAddress, pAddressPtr, true);
//Read pointer
IntPtr readPtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(uint)));
//Packet parsing
IntPtr ipHdr = IntPtr.Zero;
IntPtr ipv6Hdr = IntPtr.Zero;
IntPtr icmpHdr = IntPtr.Zero;
IntPtr icmpv6Hdr = IntPtr.Zero;
IntPtr tcpHdr = IntPtr.Zero;
IntPtr udpHdr = IntPtr.Zero;
IntPtr ppData = IntPtr.Zero;
IntPtr ppReadLen = IntPtr.Zero;
try
{
//Invoke WinDivertRecv
if (NativeMethods.WinDivertRecv(_divert_handle, bufferPtr, (uint)NativeConstants.WinDivertMaxBuffer, pAddressPtr, readPtr) == true)
{
//We received a packet
pAddress = (WINDIVERT_ADDRESS)Marshal.PtrToStructure(pAddressPtr, typeof(WINDIVERT_ADDRESS));
//This line is used to copy buffer data to managed Byte[]
//Marshal.Copy(bufferPtr, bufferArr, 0, bufferArr.Length);
//Packet length
uint readlen = (uint)Marshal.ReadInt32(readPtr);
//Try to parse data
ipHdr = IntPtr.Zero; //Marshal.AllocHGlobal(Marshal.SizeOf(typeof(WINDIVERT_IPHDR)));
ipv6Hdr = IntPtr.Zero; //Marshal.AllocHGlobal(Marshal.SizeOf(typeof(WINDIVERT_IPV6HDR)));
icmpHdr = IntPtr.Zero; //Marshal.AllocHGlobal(Marshal.SizeOf(typeof(WINDIVERT_ICMPHDR)));
icmpv6Hdr = IntPtr.Zero; //Marshal.AllocHGlobal(Marshal.SizeOf(typeof(WINDIVERT_ICMPV6HDR)));
tcpHdr = IntPtr.Zero; //Marshal.AllocHGlobal(Marshal.SizeOf(typeof(WINDIVERT_TCPHDR)));
udpHdr = IntPtr.Zero; //Marshal.AllocHGlobal(Marshal.SizeOf(typeof(WINDIVERT_UDPHDR)));
ppData = IntPtr.Zero; //Marshal.AllocHGlobal(NativeConstants.WinDivertMaxBuffer);
ppReadLen = IntPtr.Zero; //Marshal.AllocHGlobal(Marshal.SizeOf(typeof(int)));
//But WinDivertHelperParsePacket always return FALSE
//if (NativeMethods.WinDivertHelperParsePacket(bufferPtr, readlen, ref ipHdr, ref ipv6Hdr, ref icmpHdr, ref icmpv6Hdr, ref tcpHdr, ref udpHdr, ref ppData, ppReadLen) == true)
//{
NativeMethods.WinDivertHelperParsePacket(bufferPtr, readlen, ref ipHdr, ref ipv6Hdr, ref icmpHdr, ref icmpv6Hdr, ref tcpHdr, ref udpHdr, ref ppData, ppReadLen);
if (ipHdr != IntPtr.Zero)
{
Console.Write("IPV4 Src Address : ");
WINDIVERT_IPHDR dvIP = (WINDIVERT_IPHDR)Marshal.PtrToStructure(ipHdr, typeof(WINDIVERT_IPHDR));
Console.WriteLine(dvIP.SrcAddr);
}
if (ipv6Hdr != IntPtr.Zero)
{
Console.Write("IPV6 Src Address : ");
WINDIVERT_IPV6HDR dvIP = (WINDIVERT_IPV6HDR)Marshal.PtrToStructure(ipv6Hdr, typeof(WINDIVERT_IPV6HDR));
//Console.WriteLine(dvIP.SrcAddr);
byte[] ipArr = new byte[4];
ipArr[0] = (byte)dvIP.SrcAddr[0];
ipArr[1] = (byte)dvIP.SrcAddr[1];
ipArr[2] = (byte)dvIP.SrcAddr[2];
ipArr[3] = (byte)dvIP.SrcAddr[3];
System.Net.IPAddress ipAd = new System.Net.IPAddress(ipArr);
Console.WriteLine(ipAd.ToString());
}
if (icmpHdr != IntPtr.Zero)
{
Console.Write("ICMP Body : ");
WINDIVERT_ICMPHDR dvIP = (WINDIVERT_ICMPHDR)Marshal.PtrToStructure(ipv6Hdr, typeof(WINDIVERT_ICMPHDR));
Console.WriteLine(dvIP.Body);
}
//}
//Write to console
Console.WriteLine(String.Format(@"Direction : {0}, Idfx : {1}, Subidfx : {2}", pAddress.Direction, pAddress.IfIdx, pAddress.SubIfIdx));
return(true);
}
else
{
return(false);
}
}
finally
{
//Release all resources
Marshal.FreeHGlobal(pAddressPtr);
Marshal.FreeHGlobal(bufferPtr);
Marshal.FreeHGlobal(readPtr);
}
}
/// <summary>
/// Gets whether or not given ipv4 header has the more fragments flag set.
/// </summary>
/// <param name="hdr">
/// The ipv4 header.
/// </param>
/// <returns>
/// True if the given ipv4 has the more fragments flag set, false otherwise.
/// </returns>
public static bool WINDIVERT_IPHDR_GET_MF(WINDIVERT_IPHDR hdr)
{
return((ushort)((hdr.FragOff0) & 0x0020) != 0);
}
/// <summary>
/// Gets the fragment offset for the given ipv4 header.
/// </summary>
/// <param name="hdr">
/// The ipv4 header.
/// </param>
/// <returns>
/// The extracted fragment offset from the given ipv4 header.
/// </returns>
public static ushort WINDIVERT_IPHDR_GET_FRAGOFF(WINDIVERT_IPHDR hdr)
{
return((ushort)((hdr.FragOff0) & 0xFF1F));
}
/// <summary>
/// Sets the reserved flag to the given value.
/// </summary>
/// <param name="hdr">
/// The ipv4 header.
/// </param>
/// <param name="val">
/// The reserved flag value.
/// </param>
public static void WINDIVERT_IPHDR_SET_RESERVED(WINDIVERT_IPHDR header, ushort val)
{
header.FragOff0 = (ushort)(((header.FragOff0) & 0xFF7F) | (((val) & 0x0001) << 7));
}
/// <summary>
/// Sets the don't fragment flag to the given value.
/// </summary>
/// <param name="hdr">
/// The ipv4 header.
/// </param>
/// <param name="val">
/// The don't fragment flag value.
/// </param>
public static void WINDIVERT_IPHDR_SET_DF(WINDIVERT_IPHDR header, ushort val)
{
header.FragOff0 = (ushort)(((header.FragOff0) & 0xFFBF) | (((val) & 0x0001) << 6));
}
/// <summary>
/// Sets the fragment offset for the given ipv4 header.
/// </summary>
/// <param name="hdr">
/// The ipv4 header.
/// </param>
/// <param name="val">
/// The fragment offset.
/// </param>
public static void WINDIVERT_IPHDR_SET_FRAGOFF(WINDIVERT_IPHDR header, ushort val)
{
header.FragOff0 = (ushort)(((header.FragOff0) & 0x00E0) | ((val) & 0xFF1F));
}
