public override void PushTraffic(Frame fInputFrame)
{
NATDescriptionFrame ndFrame = new NATDescriptionFrame(NATDescriptionFrame.NATFrameSource.Internal);
ndFrame.EncapsulatedFrame = fInputFrame;
base.PushTraffic(ndFrame);
}
public void PushExternalTraffic(Frame fFrame)
{
NATDescriptionFrame ndFrame = new NATDescriptionFrame(NATDescriptionFrame.NATFrameSource.External);
ndFrame.EncapsulatedFrame = fFrame;
base.PushTraffic(ndFrame);
}
/// <summary>
/// Extracts a IP frame and does some NAT
/// </summary>
/// <param name="fInputFrame">The frame to handle</param>
protected override void HandleTraffic(Frame fInputFrame)
{
int iSourcePort = 0;
int iDestinationPort = 0;
if (fInputFrame.FrameType != NATDescriptionFrame.DefaultFrameType)
{
throw new Exception("A frame without a NATDescription was received by the NAT handler. This must not happen and indicates a serious internal error.");
}
NATDescriptionFrame ndDescription = (NATDescriptionFrame)fInputFrame;
fInputFrame = ndDescription.EncapsulatedFrame;
IP.IPFrame ipFrame = GetIPv4Frame(fInputFrame);
TCP.TCPFrame tcpFrame = GetTCPFrame(fInputFrame);
UDP.UDPFrame udpFrame = null;
if (tcpFrame != null)
{
iSourcePort = tcpFrame.SourcePort;
iDestinationPort = tcpFrame.DestinationPort;
}
else
{
udpFrame = GetUDPFrame(fInputFrame);
if (udpFrame != null)
{
iSourcePort = udpFrame.SourcePort;
iDestinationPort = udpFrame.DestinationPort;
}
}
if (ipFrame != null)
{
if (ndDescription.Source == NATDescriptionFrame.NATFrameSource.Internal)
{
//In to out
if (IsInternalRange(ipFrame.SourceAddress))
{
HandleFromInternal(fInputFrame, iSourcePort, iDestinationPort, ipFrame, tcpFrame, udpFrame);
}
else
{
NotifyNextExternal(fInputFrame);
}
}
else if (ndDescription.Source == NATDescriptionFrame.NATFrameSource.External)
{
//Out to in
if (IsExternalRange(ipFrame.DestinationAddress))
{
HandleFromExternal(fInputFrame, iSourcePort, iDestinationPort, ipFrame, tcpFrame, udpFrame);
}
else
{
NotifyNextInternal(fInputFrame);
}
}
}
}