Re: Possibility to determine state of a connection

[Dan Williams <dcbw redhat com>]

On Tue, 2013-02-12 at 21:18 +0100, Martin Steuer wrote:
> I started using NetworkManager on a fresh installation of mine and 
> noticed a problem regarding PPPoE connections: When establishing a PPPoE 
> connection via ethernet an existing IP connection is disconnected. Thus 
> loosing IP connectivity on the local network.

This has been an issue for a long time in NM, and it needs to be
addressed in a more complete manner.  Basically, we need to run both the
original eth connection and the PPPoE one in parallel.  In reality, this
looks a lot like a VPN, and perhaps we should treat it as such.  Or,
really, it's just a tunnel like a VPN is a tunnel, and we should have a
more generic framework for handling tunnel interfaces.

That would imply a change in behavior of NM as D-Bus clients would see
it, so perhaps this would have to wait a bit until we support multiple
VPN connections.  Which is something I'm happy to provide some guidance
on if anyone wants to work on it?

Dan

> This is obviously not necessary as these two connections can perfectly 
> co-exist on a single device, both communicating via ethernet frames on 
> the wire. While all hosts on the LAN are reachible via IP a machine may 
> additionally create a connection with the DSL access concentrator thus 
> providing internet connectivity.
> 
> At first I thought the observed behaviour might be a configuration 
> problem on my end, but after further investigation I realized that this 
> seems to be the standard behaviour of NetworkManager. A quick search on 
> the net revealed that some, albeit not many, people had same problems.
> 
> Find attached a very simple but incomplete patch. As it currently is, it 
> will not be really useful. While I can create a PPPoE session this way 
> without interfering with an existing LAN connection on the same device 
> it has issues when one tries to reconnect the PPPoE session while it is 
> already established. This will result in a pppd which eventually fails 
> after a timeout.
> 
> I do have the impression that it is not possible to check the state of
> a connection. Instead, only a device does have a connection state, and I 
> find this to be very limiting.
> This forces the current implementation right at the point of my patch:
> Even if a requested connection is already established, that one will be 
> shut down, just to be brought back up again and it also makes it harder 
> for connections to share a device.
> If there was the possibility to check if a certain connection is already 
> in place my patch could be made to work, and unneccessary reconnects 
> could be avoided.
> 
> I do understand that the concept of connections is not bound to a 
> certain device, this makes it even more important for the state 
> information to be associated with a connection and not a device.
> 
> Is it correct that there is no connection state associated with a 
> connection?
> Would there be another way to achieve what I am after?
> 
> Thanks for your help!
> Martin
> _______________________________________________
> networkmanager-list mailing list
> networkmanager-list gnome org
> https://mail.gnome.org/mailman/listinfo/networkmanager-list