[Discuss-gnuradio] TunTap device problem in GRC

[Ed Criscuolo]

Has anybody had any luck using the Tun/Tap device in GRC?

I've tried it with GRC 0.70 and 0.69 under Fedora 8, and
GRC 0.69 under Mac OSX and had no luck, even when running
everything as root.

Under OSX 10.4, I installed Mattias Nissler's tun/tap driver
( http://tuntaposx.sourceforge.net/ ) dated 2008-Aug-4. It
creates all the /dev/tun<x> and /dev/tap<x> devices
right away, and doesn't seem to have the /dev/net/tun
master device. (Michael Dickens, have you had any experience
with the tun/tap driver on OSX?) Trying to use the
/dev/tun0 in place of /dev/net/tun predictably failed,
producing

    ifs = ioctl(tun_fd, TUNSETIFF, struct.pack("16sH", 
virtual_device_filename, mode))
IOError: [Errno 25] Inappropriate ioctl for device

----

Under Fedora 8, with either GRC 0.69 or 0.70, things
went a little better, but not much.  With the following
flow graph


----------      ----------------------    -----------
|        |      |   Tun/Tap          |    |         |
| Vector |----->| Dev = /dev/net/tun |--->|  File   |
| Source |      | Virt Dev = tun%d   |    |  Sink   |
|        |      | IP addr = 10.0.0.1 |    |         |
----------      ----------------------    -----------

things ran without error and the net pseudo-device "tun0"
was created, but an ifconfig showed that no IP address
was assigned to it. I successfully used ifconfig to
assign address 10.0.0.1 to it, and sent packets to
that address, but nothing was captured in the file.
And another 'ifconfig tun0' showed that no new TX bytes
had been sent out the interface.

Is there an error in GRC that results in the IP address
not being assigned?  And why didn't my packets get there
when there WAS an address assigned?

@(^.^)@  Ed