Re: libnetfilter_queue - remove packet from kernel buffer, and reinject later

[Eric Leblond <eric@inl.fr>]

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Hello,

Le mercredi 20 janvier 2010 à 22:13 +0200, Mistick Levi a écrit :
> 2010/1/20 Eric Leblond <eric@inl.fr>:
> > Hello,
> >
> > Le mardi 19 janvier 2010 à 21:25 +0200, Mistick Levi a écrit :
> >> Hi,
> >> I've worked with libipq, and libnetfilter_queue, and i got to a place
> >> where my userspace code can't get anymore packets( with the message:
> >> netlink message: no buffer space available ) .
> >>
> >> Now what i want to do is this:
> >> Read a packet from the queue, copy it to my own queue/location in my
> >> program, and re injecting the packet later on with my verdict, after i
> >> finished.
> >
> > This is how it works ;)
> >
> > In fact, the 'no buffer space available' message is due to your program
> > not getting packets as fast as needed: The kernel is sending packet to a
> > netlink socket and the internal buffer of the socket gets filled with
> > the packets waiting to be read.
> >
> > What you need to do is:
> >      * read packet as fast as you can (your callback function has to be
> >        fast)
> >      * do the intensive or delay needing work outside of the callback
> >        (via a thread or something)
> 
> What do you mean by doing the delay needing work outside of the
> callback? in the end of the callback i should give a verdict, no ?

No, this is not necessary. The verdict can be called from anywhere else
in your program.

BR,


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

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