From: Thomas Graf <tgraf@suug.ch>
To: Pablo Neira <pablo@eurodev.net>
Cc: netdev@oss.sgi.com,
Netfilter Development Mailinglist
<netfilter-devel@lists.netfilter.org>,
Harald Welte <laforge@gnumonks.org>
Subject: Re: [RFC] string matching based packet classification/filtering
Date: Thu, 17 Feb 2005 14:31:14 +0100 [thread overview]
Message-ID: <20050217133114.GU31837@postel.suug.ch> (raw)
In-Reply-To: <4213ECC9.30502@eurodev.net>
> >The matching algorithm would parse the array as a finite automation
> >eating up byte by byte in the text.
> >
>
> Looks good but Boyer-Moore algorithm doesn't need this at all. BM
> doesn't support wildcards like '*' because of the shiftings that it uses
> to look for matches. This issue together with memory consumption are two
> limitations that we have to live with if we want to use BM. Anyway I
> think it's worth it because we can perform search in O(n/m).
This would be _additional_ to BM/KMP/naive/finite automata/you name it.
The benefit of libqsearch is hide various algorithms behind a single
interface, isn't it? It's argueable whether it would make sense to try
and rule out bad shifts while parsing a chain of non-wildcard regular
expression tokens but I guess that would be over the top.
prev parent reply other threads:[~2005-02-17 13:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-15 20:32 [RFC] string matching based packet classification/filtering Thomas Graf
2005-02-15 21:41 ` Pablo Neira
2005-02-15 21:56 ` Thomas Graf
2005-02-16 22:30 ` Thomas Graf
2005-02-17 1:00 ` Pablo Neira
2005-02-17 13:31 ` Thomas Graf [this message]
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