Capturing Layer 3 Traffic

Peter John · 01-08-2007, 02:10 AM

We have our own Bluetooth STack functional on Linux. We want to implement "IP Over Bluetooth" functionality. How can we make the kernel to route TCP/IP traffic to our BT stack ??

raskin · 01-08-2007, 03:28 AM

Try enabling tap/tun network interface. You can then make kernel route everything needed through this interface - by standard routing configuration means, like 'ip route' or 'route' - and simply put program that translates packets to your BT stack and back on the other end of tun/tap. See documentation in kernel source.

Peter John · 01-08-2007, 04:33 AM

Any idea as to when the kernel will write into the tunX interface ??? every IP packet ?

Any good example program available?

raskin · 01-08-2007, 04:48 AM

You will configure this interface - as usual - to have some IP and you will set up routing so that some packets will have to be routed through it. So everything that is routed through tun interface will be caught on tun device.

Peter John · 01-08-2007, 04:53 AM

Like ifconfig /dev/tun0 192.168.0.1. Ping 192.168.0.2 will be captured on dev/tun0 ??