Re: Some various thoughts on PPP

["Tambet Ingo" <tambet gmail com>]

Hey,

On 5/17/07, Ulrik Mikaelsson <ulrik mikaelsson gmail com> wrote:
[snip]
> Please jump in with your thoughts and ideas. I'm planning to attempt
> hacking some of this together, but I'd like to get some feedback
> first, to ensure I'm right on track. Also, if you're hacking on
> something related, please let me know so we don't waste a lot of good
> effort.

I am working on exactly that. It's been a very long journey since NM
was written for wired and wireless devices and adding a new device
type (modem) cleanly wasn't really possible (in NM 0.6 branch). After
a lot of rework that's gone in to svn trunk, the devices are more
abstract, the device activation takes an abstract NMConnection
structure for activation info (like IP configuration, wireless
security, modem options, ppp options), etc.

That's not where the pain ends, it turns out there are no modem
dialers that are usable for NM. There actually seem to be only two (at
least popular ones), wvdial and chat. wvdial is C++, has a bunch of
C++ dependencies and has no way to just dial without starting pppd
(which NM will need for general PPP support). chat isn't really a
dialer either. Pretty much all the other "dialers" seem to be just
frontends for these two. If anyone knows a dialer that would fit for
NM, please let me know, I'd love to throw away what I've come up with
so far.

That is yet not all, it also turns out HAL doesn't have any notion of
modems so the best we can do for now is to get a list of HAL devices
with capability "serial" and try to send some modem initialization
strings and see if they respond. That is for the serial devices that
actually show up in HAL at all. Most of the thinkpads have a modem
that only works with proprietary HSF modem driver and these do not
show up in HAL at all.

So it all has been surprisingly hard. For this last week I've been
working on the actual modem device and ppp interface for NM. The
current status is that NM is able to dial out and establish a serial
connection that is suitable for ppp. There's a wrapper that turns NM
activation structure NMConnection to PPP command line, starts pppd
with a special pppd plugin that'll report ppp events (like "got IP
information", warnings, errors, etc). I'm planning to get all this to
svn next week. If you're interested in helping out, I would love to
answer any questions you have about it!

Tambet