Re: DSL under Wireless

[Dan Williams <dcbw redhat com>]

On Tue, 2009-09-22 at 14:47 -0700, Habib Seifzadeh wrote:
> > > 
> 
> > > First of all, thank you guys for the great software, NetworkManager.
> > > The only problem that I have with it is DSL connection. As all of us
> > > know, today many DSL modems are equipped with Wifi which is much
> > > better than ethernet. But it seems that NetworkManager doesn't support
> > > DSL under wifi. My question is that why NetworkManager does categorize
> > > DSL just under wired connecions? Why it doesn't provide a separate
> > > menu for DSL connections like VPN connection? Is it better that the
> > > type of permanent connection doesn't matter to DSL?
> > 
> > Right now NM doesn't allow PPPoE over arbitrary interfaces, which was a
> > design oversight when PPPoE got added.  That's not hard to fix, it just
> > needs to be done.  When that gets done, we'll also add the ability to
> > keep the local subnet IP address on eth0/wlan0 as well, which is often
> > requested.
> > 
> > PPPoE is more like a VPN than an actual connection method in that it
> > creates a virtual tunnel interface on top of an actual physical
> > interface.
> > 
> > Dan
> 
> Dear Dan and other friends,
> 
> Have supporting of PPPoE over arbitrary interfaces been implemented? Can I update the NM code by myself? Which module must I update?

Would be great if you wanted to poke at this and try to get some patches
for it.  I'd be happy to help guide you through what I think would be
necessary.

There are a couple of parts to this.  First, we need to remove the "DSL"
page from the connection editor, and instead add a "PPPoE" page to each
connection editor window with a checkbox that says "use PPPoE on this
connection" much like the 802.1x tab for wired connections.  The same
thing would get added to Wireless connections.

Inside NM, we need to make the PPPoE handling code more generic.  It's
currently only implemented for wired devices in
src/nm-device-ethernet.c, but we could split that out into common code
in src/ppp-manager/ somewhere that both the NMDeviceEthernet and
NMDeviceWifi objects can use inside NM.

Then there's the question of what stage the PPPoE connection should run
at.  Each NMDevice object (of which Ethernet and Wifi are subclasses)
proceed from the DISCONNECTED state through a few others like IP_CONFIG
and such to the ACTIVATED state.  We still want to bring up the
underlying device's IP config, and *then* bring up the PPPoE
connection's IP config after that.  The internal structure of NM is such
that it's geared towards only one IP config at the moment, which is why
we currently don't try to set up the ethernet device's IP stuff, but
instead do PPPoE.

I'm not quite sure how to go about putting in the PPPoE stages and
applying the config since we don't want to call the device "ready" until
*both* the underlying IP config *and* the PPPoE config are up.  In that
way PPPoE is more like a VPN, but we can also run the VPN on top of the
PPPoE...

One thought would be to do both the PPPoE and the eth/wifi bringup in
parallel with a waterfall approach where each device stage isn't
complete until *both* the eth/wifi and PPPoE bits for that stage were
done.  I guess that's the easiest approach.

Sound interesting to do?  I can outline my thoughts for that.

Dan