Fwd: BIRD unable to read data from TUN/TAP device

[Cyrill Gössi]

Thank you very much for getting back to me in this matter!

As for my scenario: in the long run I need to be able to let a single BIRD
process run as many as 10000 OSPF protocol instances, each of which
communicating locally over an individual TUN/TAP device. In the end, a
single Linux system therefore has to be able to support 10000 TUN/TAP
devices.

As for your ideas and suggestions to check: Having tap1 and tap2 on one
system, I'm able to ping tap2 via tap1. Running OSPF in NBMA mode resulted
in no messages received by the tap devices at all.

I updated my stackoverflow question and included also a strace()-extract of
BIRD. In it you see the setup of a socket for a tap device and the
inclusion of the file-descriptor for this socket into the set of
descriptors observed by the selcet() system call. But unfortunately
select() never notices any data ready to be read by this socket
file-descriptor.

With the additional information about my scenario and the results of your
ideas and suggestions, I kindly ask you to take another look at the updated
question on stackoverflow.

I'm thankful for all the time you or somebody else will invest into
supporting me in this matter!

Best, Cyrill


2014/1/15 Ondrej Zajicek <santiago at crfreenet.org>

> On Mon, Jan 13, 2014 at 02:01:48PM +0100, Cyrill Gössi wrote:
> > Hi
> >
> > I'm trying to let BIRD communicate over virtual network devices created
> by
> > the Linux TUN/TAP module.
> >
> > As it seems the tap devices receive the messages from BIRD. However, BIRD
> > does not seem to receive the messages sent to it over the tap device.
> >
> > I described the scenario and the issues I run into in more detail on
> > stackoverflow.
>
> I am not sure if i understand your scenario, but if you run both TUN/TAP
> endpoints on one machine, i would be surprised if OS network code wouldn't
> be confused by that. If not, you should try ping and try to run OSPF
> in NBMA mode (which will use just unicasts).
>
> > If somebody has some experience with running BIRD over TUN/TAP devices,
>
> Generally, it works over OpenVPN tunnels, which use TUN/TAP devices,
> but in that cases both endpoints are on different machines.
>
> --
> Elen sila lumenn' omentielvo
>
> Ondrej 'SanTiago' Zajicek (email: santiago at crfreenet.org)
> OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
> "To err is human -- to blame it on a computer is even more so."
>
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