All of lore.kernel.org
 help / color / mirror / Atom feed
From: Changli Gao <xiaosuo@gmail.com>
To: Jan Engelhardt <jengelh@medozas.de>
Cc: Balaji Venkatamohan <bvenkat@ncsu.edu>, netfilter-devel@vger.kernel.org
Subject: Re: how to use regex inside new netfilter extension modules?
Date: Thu, 4 Mar 2010 09:33:04 +0800	[thread overview]
Message-ID: <412e6f7f1003031733n68bfa158v1b590a41c2ffa3d2@mail.gmail.com> (raw)
In-Reply-To: <alpine.LSU.2.01.1003031954001.25372@obet.zrqbmnf.qr>

On Thu, Mar 4, 2010 at 2:56 AM, Jan Engelhardt <jengelh@medozas.de> wrote:
> 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?

Please refer to the source code of l7filter. http://l7-filter.sourceforge.net/

>
> 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.

REs are useful and cheapest in some conditions.

-- 
Regards，
Changli Gao(xiaosuo@gmail.com)
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

      reply	other threads:[~2010-03-04  1:33 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
2010-03-04  1:33   ` Changli Gao [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=412e6f7f1003031733n68bfa158v1b590a41c2ffa3d2@mail.gmail.com \
    --to=xiaosuo@gmail.com \
    --cc=bvenkat@ncsu.edu \
    --cc=jengelh@medozas.de \
    --cc=netfilter-devel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.