ipq and nf_queue compatibility

ipq and nf_queue compatibility

[robert]

Hello,

I am porting a program that uses IPQ to NF_QUEUE, and the port went  
very smoothly, but I noticed that if I run the nfqueue version once,  
the ipq version stops working.  The NF_QUEUE version always works,  
but the other one simple stops functioning.  Is there a known  
incompatibility between the two?  Or perhaps is there some global  
state that I need to cleanup inside of the NFQUEUE version before I  
execute the IPQ version.  The kernel has both IPQ and NFQUEUE support.

This happens regardless of whether or not I call the function  
nfq_unbind_pf on exit.  Not really sure what that function does, but  
it was inside of nfqnl_test.c, so I tried it out.

any ideas?
--robert

Re: ipq and nf_queue compatibility

[Patrick McHardy]

robert wrote:
> Hello,
> 
> I am porting a program that uses IPQ to NF_QUEUE, and the port went 
> very smoothly, but I noticed that if I run the nfqueue version once, 
> the ipq version stops working.  The NF_QUEUE version always works,  but
> the other one simple stops functioning.  Is there a known 
> incompatibility between the two?  Or perhaps is there some global  state
> that I need to cleanup inside of the NFQUEUE version before I  execute
> the IPQ version.  The kernel has both IPQ and NFQUEUE support.
> 
> This happens regardless of whether or not I call the function 
> nfq_unbind_pf on exit.  Not really sure what that function does, but  it
> was inside of nfqnl_test.c, so I tried it out.

ip_queue only registeres itself when the module is loaded,
nfnetlink_queue registeres when NFQNL_CFG_CMD_PF_BIND is
received. So once ip_queue has been unregistered it never
registeres again and doesn't receive any packets anymore.

Re: ipq and nf_queue compatibility

[robert]

is there any sequence that will insure both ipq and nfqueue work?   
should it just never unbind then?  I am a little unclear what the  
difference is between unregister and unbind?

--robert

On Oct 10, 2006, at 10:59 PM, Patrick McHardy wrote:

> robert wrote:
>> Hello,
>>
>> I am porting a program that uses IPQ to NF_QUEUE, and the port went
>> very smoothly, but I noticed that if I run the nfqueue version once,
>> the ipq version stops working.  The NF_QUEUE version always  
>> works,  but
>> the other one simple stops functioning.  Is there a known
>> incompatibility between the two?  Or perhaps is there some global   
>> state
>> that I need to cleanup inside of the NFQUEUE version before I   
>> execute
>> the IPQ version.  The kernel has both IPQ and NFQUEUE support.
>>
>> This happens regardless of whether or not I call the function
>> nfq_unbind_pf on exit.  Not really sure what that function does,  
>> but  it
>> was inside of nfqnl_test.c, so I tried it out.
>
> ip_queue only registeres itself when the module is loaded,
> nfnetlink_queue registeres when NFQNL_CFG_CMD_PF_BIND is
> received. So once ip_queue has been unregistered it never
> registeres again and doesn't receive any packets anymore.
>

Re: ipq and nf_queue compatibility

[Patrick McHardy]

robert wrote:
> is there any sequence that will insure both ipq and nfqueue work?  
> should it just never unbind then?  I am a little unclear what the 
> difference is between unregister and unbind?

You need to unload/reload the ip_queue module if you want it
to register again after "unbinding" nfnetlink_queue from
AF_INET.