Re: Some various thoughts on PPP

["Ulrik Mikaelsson" <ulrik mikaelsson gmail com>]

Thanks for the wrap-up. Gave me a great orientation of the current status. :)

One of the things that eludes me though; how exactly are you
envisioning the NM-dialing-connection process? From what I understand,
you're planning to have NM itself dial, and then hand-over the
connection to pppd, linked in to NM? Will this be carried out in a
separate process, with DBUS-connection to the main process? Is this
somehow supporting the desire to keep network-configuration
centralized within the distribution, or will it require configuration
separate from, say /etc/ppp/peers?

> 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.
I saw things in the commit-log. Great. :)

> 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.
Well, perhaps there's another quirk to it, as far as I understand,
many modems expose several devices, for different uses. Especially,
the GRPS-datacard I tested had three of them, one for the
ppp-connection, one for chatting with the card simultaneously with the
connection, querying signal strength and such, and one for to me
unknown purposes. Somehow we'll gotta figure which is which. :)

> 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!
Sounds great! I'll definitely check it out.