cannot set TUN interface up/down with Python API (wrapper)

[Julien BERNARD]

Hi,
>
> The last working revision is 88940b71f81525b1080fcdd5a029537e9a85ca38, 
> the revision just after the 3.2.3 release.
> The next revision (ef75c4edf0930b4d745da695c5fe0075c7b3afdd) 
> introduces a segfault in the script that is resolved in the 3.2.5 
> release (this should be the fix introduced by the revision 
> 4035e5b5e88529e6c7a12c41dcd8637ed69498d9).
> Thus, I applied the fix on the revision 
> ef75c4edf0930b4d745da695c5fe0075c7b3afdd and I can confirm that the 
> problem was introduced by this revision.
> However I'm not familiar enough with all of this to determine exactly 
> what causes the bug.
>
> Could you please help me to understand what really causes this error?

I managed to fix the problem.
In fact the error is caused by the link type set to 'tun' which is not 
supported (there is nor tun.c in route/link/ neither in the python wrapper).
In C it works because I think there is a default behavior for tun 
interface but this should not correcly be implemented in python.

At the moment, in order to make this work, I simply redefined the link 
type as 'dummy' before changing the flags.
The script is thus as follow:
#!/usr/bin/env python2
import netlink.route.link as link
import netlink.core as netlink
import netlink.route.address as address

sock = netlink.Socket()
sock.connect(netlink.NETLINK_ROUTE)
cache = link.LinkCache()
cache.refill(sock)
iface = cache['tun0']
iface.type = 'dummy'
iface.flags = ['-up']
iface.change()


The libnl still returns an error (the same as for classic ethernet 
interfaces: netlink.core.KernelError: Kernel returned: Message sequence 
number mismatch) but this works.
I will try to find out why there is this problem and if there is 
something to fix in the python wrapper I would report it.

Regards,

-- 
Julien BERNARD