private void TraceTcpNatContext(NATContext context, TcpFrame frame)
{
if (context == null || frame == null)
{
return;
}
NATContext.StateCode state = NATContext.StateCode.TCP_RST; // 跟踪TCP协议报文状态
if (0 != (frame.Flags & TcpFlags.TCP_SYN))
{
state = NATContext.StateCode.TCP_SYN;
}
else if (0 != (frame.Flags & TcpFlags.TCP_FIN))
{
state = NATContext.StateCode.TCP_FIN;
}
else if (0 != (frame.Flags & TcpFlags.TCP_RST))
{
state = NATContext.StateCode.TCP_RST;
}
else if (0 != (frame.Flags & (TcpFlags.TCP_PSH | TcpFlags.TCP_ACK)))
{
state = NATContext.StateCode.TCP_RECVED;
}
if (context.State != NATContext.StateCode.TCP_FIN &&
context.State != NATContext.StateCode.TCP_RST)
{
context.Restart().State = state;
}
}
private NATContext RestartContextAgingTime(NATContext context)
{
if (context == null)
{
return(context);
}
if (this.ProtocolType != ProtocolType.Tcp)
{
return(context);
}
if (context.State == NATContext.StateCode.TCP_RECVED || context.State == NATContext.StateCode.TCP_SYN)
{
return(context.Restart());
}
return(context);
}