[En-Nut-Discussion] PPP deamon / routing

[Harald Kipp]

Ole,

Actually PPP is most simple. ;-) Everything is packed into
asynchronous HDLC telegrams. Session establishment is quite
funny and divided into three main parts:

1) LCP to negotiate the link
2) Authentication
3) IPCP to negotiate IP settings

...ECP and CCP are not really required.

In each part both(!) partners send a request with options
they wish to use. Each request is answered with options
accepted or alternate options. This request/response game
is repeated until they match. Then negotiation steps up
to the next part. If finally IPCP matches, we are done.
That's all. The rest is simply IP packed into HDLC.

dev/chat.c already provides modem conversation routines.

I don't think that mixing dial-in and dial-out is required
for the first step. But it should be kept in mind.

Did you check
http://www.ethernut.de/en/nuttecnotes/ntn-1_ppp.html

At the end of the page you'll find a link to all relevant
RFCs. Most important are
RFC1332
RFC1570
RFC1661
RFC1662 (implemented in (dev/ahdlc.c)
RFC2484

I agree, that a few changes may be required to run PPP and
Ethernet concurrently and allow routing between them.

Special care has to be taken not to force PPP code being
linked to Ethernet-only applications.

Harald




At 12:22 16.12.2004 +0100, you wrote:
>Hi Harald,
>
> > PPP server functionality is definitely one of the most
> > wanted major enhancements. As far as I know, no code
> > exists and the task isn't trivial.
>
>Yes, that's what just hold me back working on it :-) I never have done
>anything with ppp beside connecting my pc to the internet... In other
>words: I don't know anything about the ppp protocol at all.
>
>We now got a request of one of our customers. So I'll possibly have to
>work on it in future.
>
> >   1. Configure dial-in accounts
> >   2. Listening to incoming calls
>
>It does not sound too hard to implement? Do we need to implement a modem
>emulation? (at commands?)
>
>Does there exists any protocol description?
>
> >   3. Mixing dial-in and dial-out
>
>I think we don't need this at the moment, do we?
>
>What's about routing? Is NutOS able to route between different network
>devices? I think using ppp and ethernet at the same time will come along
>with better ip configuration as we discussed some days ago?
>
>If I'll need to do the development I'll shure be willing to contribute
>this code into NutOS. So is anybody else out there who has PPP knowledge
>and is willing to bring me on the right path if needed?
>
>Regards,
>
>Ole
>
>--
>kernel concepts    Tel: +49-271-771091-14
>Dreisbachstr. 24   Fax: +49-271-771091-19
>D-57250 Netphen    E+ : +49-177-7420433
>--