Re: OpenVPN with DHCP

[Dan Williams <dcbw redhat com>]

On Sun, 2007-12-30 at 17:35 +0000, Jon Escombe wrote:
> Christoph Brill wrote:
> > Was the question to complicated? Is noone interested in OpenVPN? Or is
> > everyone on holidays?
> > 
> > Am Donnerstag, den 27.12.2007, 11:52 +0100 schrieb Christoph Brill:
> >> Hi list,
> >>
> >> I'm trying to connect to a openvpn server. This server is set up to use
> >> the companies DHCP server (dnsmasq) to provide IPs to the VPN clients.
> >> >From what I understand (reading the error message of nm-applet)
> >> NetworkManager currently relies on using OpenVPNs internal "DHCP
> >> server". Is that true?
> >>
> 
> On holiday seems likely ;)
> 
> You are right, the NM code expects an IP address back directly from the 
> openvpn server. I couldn't comment on how difficult it would be to 
> provide an option to use DHCP instead...
> 
> I guess it's not an option for you to exclude a pool of addresses from 
> the dnsmasq server and allocate them to openvpn?

One question here is whether DHCP should be done in the OpenVPN plugin
or from NetworkManager itself.  Ideally it would be all handled in the
OpenVPN plugin, and then the plugin could send updates to the IP4Config
when the address settings changed (as a result of a DHCP rebind or
whatever).

However, it would be a shame to duplicate all the DHCP code in the
OpenVPN plugin too, although that's one solution.  The OpenVPN code
could spawn dhclient and pass it a dhclient script to return DHCP
options to the OpenVPN plugin via D-Bus just like NetworkManager does,
and make that part of the connection process.  It could be a lot lighter
weight than the current NM DHCP manager code because it would only have
to handle one instance of dhclient whereas NetworkManager has to handle
many at the same time.  It might be worth a look at stripping down the
NM src/dhcp-manager/ code and sucking it into the OpenVPN plugin.

Dan