Any C lib for stateful inspection of network sessions?

Is there any开发者_如何学C C/C++ lib(of course Open-sourced) for developing applications of stateful inspection on network session, for instance, following the FTP session state?

I know there is a pre-processor module in Snort namely stream4. But an independent lib is more flexible for us which implemented in C is preferred.

Thanks.

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I'm not sure how applicable this will be to whatever you're doing, but you could try to extract the Linux NAT connection tracking code and adapting it to your needs. It's not a nice pre-made library, but it's a start.