Is the libnetfilter_queue thread-safe?

Is the libnetfilter_queue thread-safe?

[Jacky Luk]

Hi,

I would like to ask a question about the 
libnetfilter_queue. Is the libnetfilter_queue thread-safe? 
Would the API of libnetfilter_queue cause the kernel crash 
under multi-threading environment? I am using the Red Hat 
Enterprise Linux 5.2 with the kernel version 
2.6.18-92.el5PAE to develop my own program. The version of 
libnetfilter_queue is 0.0.16 and the version of 
libnfnetlink is 0.0.40.

Thanks and Regards,

Jacky Luk

Re: Is the libnetfilter_queue thread-safe?

[Eric Leblond]

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Hi,

Le vendredi 23 janvier 2009 à 12:02 +0800, Jacky Luk a écrit :
> Hi,
> 
> I would like to ask a question about the 
> libnetfilter_queue. Is the libnetfilter_queue thread-safe? 

Is had yet to be decide :/ From my experience on NuFW, you can use it
with multithreaded programs and you can have a reading thread and a
writing thread working together on the same queue.

> Would the API of libnetfilter_queue cause the kernel crash 
> under multi-threading environment?

Clearly not, the worse that can happen is an application crash not a
kernel crash.

BR,
-- 
Eric Leblond <eric@inl.fr>
INL: http://www.inl.fr/
NuFW: http://www.nufw.org/

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Re: Is the libnetfilter_queue thread-safe?

[Patrick McHardy]

Eric Leblond wrote:
> Hi,
> 
> Le vendredi 23 janvier 2009 à 12:02 +0800, Jacky Luk a écrit :
>> Hi,
>>
>> I would like to ask a question about the 
>> libnetfilter_queue. Is the libnetfilter_queue thread-safe? 
> 
> Is had yet to be decide :/ From my experience on NuFW, you can use it
> with multithreaded programs and you can have a reading thread and a
> writing thread working together on the same queue.

I think it should be as long as you don't change anything related
to the handle while using it. The remaining parts are merely a
stateless communication mechanism, there's no reason why they
shouldn't be thread-safe.
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