From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pablo Neira <pablo@eurodev.net>
Subject: Re: can a netfilter hook interact with userspace ?
Date: Wed, 21 Jul 2004 18:09:44 +0200
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To: "Horton, Dave" <dhorton@pactolus.com>,
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Horton, Dave wrote:

>By what means can my userspace program call into my netfilter hook to
>communicate this information?
>  
>

You can use nf_register_sockopt/nf_unregister_sockopt to do so. See Sect 
4.6. Writing New modules -> Receiving Commands From Userspace in the 
netfilter hacking how to. You can find an example in ip_tables.c.

If you don't like using getsocksopt/setsocksopt to pass information to 
kernel space, you could also use netlinks sockets.

regards,
Pablo