netdev - Re: [RFC 1/2] netfilter: xt_condition: export list management code

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Message-ID: <1279566876.11662.102.camel@powerslave>
Date:	Mon, 19 Jul 2010 22:14:36 +0300
From:	Luciano Coelho <luciano.coelho@...ia.com>
To:	ext Jan Engelhardt <jengelh@...ozas.de>
Cc:	Netfilter Developer Mailing List 
	<netfilter-devel@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	Patrick McHardy <kaber@...sh.net>,
	"sameo@...ux.intel.com" <sameo@...ux.intel.com>
Subject: Re: [RFC 1/2] netfilter: xt_condition: export list management code

On Mon, 2010-07-19 at 18:13 +0200, ext Jan Engelhardt wrote:
> On Monday 2010-07-19 16:15, Luciano Coelho wrote:
> 
> >From: Luciano Coelho <coelho@...tbed>
> >
> >This patch isolates and exports the condition list management code, in
> >preparation for the CONDITION target to use it.  No functional change,
> >just reorganization of the code.
> 
> Well, I guess it would make more sense if the two extensions be in a 
> single file. That would alleviate the need for export reorganizations, 
> and also works because the module metadata overhead is large already.

Right.  I'll change the code so that the two extensions are in the same
file/module.  You're the second person to mention this already. ;)


> >@@ -3,12 +3,27 @@
> > 
> > #include <linux/types.h>
> > 
> >+#define XT_CONDITION_MAX_NAME_SIZE 30
> >+
> > struct xt_condition_mtinfo {
> >-	char name[31];
> >+	char name[XT_CONDITION_MAX_NAME_SIZE + 1];
> > 	__u8 invert;
> 
> Oh noes. Please please avoid any math operations inside []. It has 
> already driven XT_FUNCTION_MAXNAMELEN into nuts ("was it now +1 or -1, 
> or even -2 that we needed to pass for various functions?"). Just let MAX 
> be 31 and have name[MAX].

Yeah, I had already done as you suggested in my previous module
(IDLETIMER), I don't know what I had in my head today when I did it
differently.  Even the name of the macro is totally wrong (_SIZE), it
would make a tiny little bit more sense if it was _LEN.  I'll change it.


> > MODULE_ALIAS("ip6t_condition");
> > 
> >-struct condition_variable {
> >-	struct list_head list;
> >-	struct proc_dir_entry *status_proc;
> >-	unsigned int refcount;
> >-	bool enabled;
> >-};
> 
> Given your excellent usage example of a CONDITION target, I think it 
> even makes sense to enlarge the "enabled" variable to a full-fledged 
> 32-bit value that can be &, | and ^'d, similar to nfmark.

Ok, that's a good idea, I'll do that.

Thanks for your comments!


-- 
Cheers,
Luca.

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