private void HandleFromInternal(Frame fInputFrame, int iSourcePort, int iDestinationPort, IP.IPFrame ipFrame, TCP.TCPFrame tcpFrame, UDP.UDPFrame udpFrame)
{
NATEntry neEntry = GetTranslationEntry(ipFrame.SourceAddress, ipFrame.DestinationAddress, iSourcePort, iDestinationPort, ipFrame.Protocol);
if (neEntry == null)
{
neEntry = CreateTranslationEntry(ipFrame.SourceAddress, ipFrame.DestinationAddress, iSourcePort, iDestinationPort, ipFrame.Protocol);
}
ipFrame.SourceAddress = neEntry.TranslatedSourceAddress;
if (tcpFrame != null)
{
tcpFrame.SourcePort = neEntry.TranslatedSourcePort;
tcpFrame.Checksum = tcpFrame.CalculateChecksum(ipFrame.GetPseudoHeader());
CheckForTCPFinish(tcpFrame, neEntry);
}
else if (udpFrame != null)
{
udpFrame.SourcePort = neEntry.TranslatedSourcePort;
udpFrame.Checksum = udpFrame.CalculateChecksum(ipFrame.GetPseudoHeader());
}
NotifyNextExternal(ipFrame);
}
private void HandleFromExternal(Frame fInputFrame, int iSourcePort, int iDestinationPort, IP.IPFrame ipFrame, TCP.TCPFrame tcpFrame, UDP.UDPFrame udpFrame)
{
NATEntry neEntry = GetReTranslationEntry(ipFrame.DestinationAddress, ipFrame.SourceAddress, iDestinationPort, iSourcePort, ipFrame.Protocol);
if (neEntry != null)
{
ipFrame.DestinationAddress = neEntry.OriginalSourceAddress;
if (tcpFrame != null)
{
tcpFrame.DestinationPort = neEntry.OriginalSourcePort;
tcpFrame.Checksum = tcpFrame.CalculateChecksum(ipFrame.GetPseudoHeader());
CheckForTCPFinish(tcpFrame, neEntry);
}
else if (udpFrame != null)
{
udpFrame.DestinationPort = neEntry.OriginalSourcePort;
udpFrame.Checksum = udpFrame.CalculateChecksum(ipFrame.GetPseudoHeader());
}
NotifyNextInternal(ipFrame);
}
else
{
PushDroppedFrame(fInputFrame);
if (bThrowOnNonNATFrame)
{
throw new Exception("The external frame was discarded because there was no corresponding translation entry in the database. (Source: " + ipFrame.SourceAddress + "/" + iSourcePort + ", Destination: " + ipFrame.DestinationAddress + "/" + iDestinationPort + ", Protocol: " + ipFrame.Protocol.ToString());
}
}
}