From mboxrd@z Thu Jan  1 00:00:00 1970
From: Patrick McHardy <kaber@trash.net>
Subject: Re: New target: can't delete rule
Date: Thu, 08 Sep 2005 00:34:52 +0200
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Cc: Gervasio Bernal <gervasiobernal@speedy.com.ar>,
	netfilter-devel@lists.netfilter.org
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To: Pablo Neira <pablo@eurodev.net>
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Pablo Neira wrote:
> I bet that you have a pointer in the private info section of the target.
> See that iptables sets that pointer to NULL at rule creation.
> Afterwards, once checkentry() is called, such pointer won't be NULL
> anymore.
> 
> At removal, the rule built by iptables sets that pointer to NULL. Such
> rule will be compared with the ruleset hold in kernel space but no
> matches will be found since the pointers mismatch.
> 
> This problem is well known and it's very easy to fix up (look for
> userspacesize and offsetof in iptables/extensions). See ipt_limit,
> ipt_CLUSTERIP...

Thanks, I didn't know about this problem. We should really focus on
a netlink interface to iptables once nf_conntrack is in, even without
pkttables.