Re: How to re-send out the packets captured by my hook function at NF_IP_PRE_ROUTING

["Real Oneone" <realoneone@gmail.com>]

Many thanks, David!

I've read what you mentioned and since I've done most of the work in
kernelspace, I wonder if there is any way to send out the modified
packet directly, when of course the mac address is not filled?

Thanks again!

2006/4/26, David G. <kiddion@zonnet.nl>:
> Real Oneone wrote:
> > Hi, I plugged a callback function into netfilter at the hook point of
> > NF_IP_PRE_ROUTING, tring to capture all the packets, make
> > some changes to some of them, and invoke skb->dev->hard_start_xmit to
> > send them out directly. However, the kernel crashed before I could get
> > any printked information.
> >
> > If you have any idea of how to send the received packets out, please tell me.
>
> You might want to explore the possibilities of the existing "ip_queue"
> kernel extension instead, it was design to do packet
> capture/inspection/changing in userspace.
>
> FireFlier works that way ( http://fireflier.sourceforge.net/ ) and so
> does inlined snort (http://www.snort.org/docs/snort_manual/node7.html).
>
> You can take a look at:
> http://www.linuxia.de/netfilter.en.html#userspace and
> http://www.cs.princeton.edu/~nakao/libipq.htm for an example application.
>