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From: Pierre Rondou <prondou@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netfilter-devel@vger.kernel.org, evyncke@cisco.com,
	guy.leduc@ulg.ac.be, Cyril Soldani <cyril.soldani@ulg.ac.be>
Subject: Re: EXPORT_SYMBOL missing in the kernel?
Date: Tue, 24 May 2011 15:48:13 +0200	[thread overview]
Message-ID: <4DDBB71D.6080205@gmail.com> (raw)
In-Reply-To: <1306244451.3026.42.camel@edumazet-laptop>

Le 24/05/11 15:40, Eric Dumazet a écrit :
> Le mardi 24 mai 2011 à 15:03 +0200, Pierre Rondou a écrit :
>    
>> Hello,
>>
>> I'm a student at the University of Liege, currently developing a NAT64
>> (see RFC 6146) module for Netfilter.
>>
>> In order to develop this module, I had to use some in-kernel function,
>> such as icmp_send, ip6_output, ip_finish_output, ... and many more.
>>
>> But many of those functions didn't have an "EXPORT_SYMBOL" allowing them
>> to be reachable from outside the kernel.
>>
>> So, to be able to use them, I had to copy paste about 1500 lines of
>> kernel source code (those functions + related functions). This makes the
>> module hardly updatable as all those functions are likely to be updated.
>>
>> Is there a reason why those functions are not associated with an
>> "EXPORT_SYMBOL"?
>>      
> We dont export all possible symbols (each export has a memory cost)
>
> We export one symbol when its needed from a module.
>
> Dont copy/paste code, but add EXPORT_SYMBOL when/if needed.
>
> icmp_send() is for sure already exported (needed in various netfilter
> modules)
>
>    

Ok, thanks for the info.

Though, my module doesn't need a kernel recompilations as its developed 
for Xtables, I'm not likely to develop a kernel patch to apply for each 
kernel my module could be connected.

Of course, the best way would be to patch the currently dev kernel 
(2.6.39 if I take your word from previous mail) to use my module.
But I'm not a kernel developper and my previously proposed module 
(NATIVI, which had the same problem) didn't seem to get interest from 
kernel or Xtables developers :(
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  reply	other threads:[~2011-05-24 13:48 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-24 13:03 EXPORT_SYMBOL missing in the kernel? Pierre Rondou
2011-05-24 13:40 ` Eric Dumazet
2011-05-24 13:48   ` Pierre Rondou [this message]
2011-05-24 14:41     ` Jan Engelhardt
2011-05-24 15:42       ` Pierre Rondou
2011-05-24 21:32         ` Jan Engelhardt
2011-05-25 13:05           ` Pierre Rondou

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