On 10/03/2012 10:21 AM, Iain Young, G7III wrote: > Hi Folks, > > Finally getting around to playing with some of the stuff in gr-extras. > > Having compiled 3.6.2, and the extras, I found the tuntap block, and > was hoping to use it to implement some RF Networking with the GMSK > modules. > > I found the tuntap block, and noticed that it had an input and output. > I was expecting my flowgraph to take the userspace end of the network > interface, with the other end being the network device. > > I found the presentation from the recent conference on a basic MAC > layer, and that seemed to imply the input could be almost anything, > but didn't leave me any the wiser as to exactly how to use it. >
Basically, the TUN/TAP block was there for the purposes of replacing tunnel.py. Few people *actually* want to pipe stuff through a virtual ethernet interface. For the example, we will probably replace that block with the "socket msg" block. You can just open netcat on the host/port and use it like a wireless IM chat session :-) There will soon be a demonstration video w/ the MAC layer stuff presented. > What I was hoping to do was essentially this (and a similiar) RX chain: > > tuntap --> packet framer --> GMSK_Mod --> USRP > Instead, try the "socket to blob" block. Outside the flowgraph, open a socket and send packets. > But the input to the tuntap block has confused me. Can I just give > it a Null source ? (With the block picking up data from the network > device ?) > > I pushed a change adding <optional>1</optional> to the input and output ports. You shouldnt need to actually connect. > Also, even when connecting it to a source, I seem to have another > issue, as I get this error at runtime: > > RuntimeError: gr_make_tuntap: tun_alloc failed > > Despite having the /dev/net/tun device, and it being writable by the > user running the flow graph. This happens if I specify "Automatic" or > a specific network device. > > Anyone want to point me in the right direction ? Or even anyone have > an example ? > I think you need to run as root to allocate tun/tap stuff. I copied the tun_alloc from here: /usr/src/linux/Documentation/networking/tuntap.txt -josh _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
