From: Jan Engelhardt <jengelh@medozas.de>
To: Balaji Venkatamohan <bvenkat@ncsu.edu>
Cc: netfilter-devel@vger.kernel.org
Subject: Re: how to use regex inside new netfilter extension modules?
Date: Wed, 3 Mar 2010 19:56:07 +0100 (CET) [thread overview]
Message-ID: <alpine.LSU.2.01.1003031954001.25372@obet.zrqbmnf.qr> (raw)
In-Reply-To: <63409.152.14.240.190.1267641716.squirrel@webmail.ncsu.edu>
On Wednesday 2010-03-03 19:41, Balaji Venkatamohan wrote:
>
>I need to use regular expressions inside the point of decision match
>function. I could not use 'regex.h ' or any other standard C library
>inside any of xt_*.c or xt_c*.h files. I could also see that none of the
>netfilter match extensions have them. I would also like to know why is it
>so?
Regular expressions are not the cheapest, both time and memory-wise:
you have to keep in mind NF runs in irq context. Furthermore, since
you only see single packets rather than the connection stream, regexes
prove to be far less useful.
next prev parent reply other threads:[~2010-03-03 18:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-03 18:41 how to use regex inside new netfilter extension modules? Balaji Venkatamohan
2010-03-03 18:56 ` Jan Engelhardt [this message]
2010-03-04 1:33 ` Changli Gao
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