[openbeosnetteam] Re: How to do PPP?

> David wrote:
> > so, I've stared playing and have discovered some useful stuff.
> > I even have PPP working over my aserial device and have the
> > start of a ppp module, but is this the right way to do it???
>
> AFAIK, PPP and his related sub-protocols (NCPs, LCPs, etc...) live
> at data-link layer level.

Yes, this is true.

>
> Someone would say let's make a NS_LAYER_LINK1 "ppp" module for our
> stack. Like our "ethernet" module.
>
> But the "ppp" module should have to work on a "serial" interface
> (Serial PPP), or on one of our already working "ethernet" interface
> (PPPoE), or even on one of a future "atm" interface (PPPoA) maybe.
> Or even on multiple interfaces at once (Multilink PPP!) 8-o

Yes, exactly.

>
> So, it looks like he should act himself as a interface (for dial on
> demand, timeout hangup), so that classic ifconfig up and down
> commands can drive him, but he would rely on a sub-interface.
>
> This will need some design change on our stack, I guess:
> modules stackibilty at same layer level?

Shouldn't need much change to allow this.

> For the PPP sub-protocols (ILCP, CHAP, PAP, etc), they can be made
> modules as well (network/ppp/*), but they would not be managed by
> the core module, but the ppp module himself. So, they can share
> a different API than the generic stack modules one, if it's needed.

This is OK as well. BTW, initially I think LCP will just be rolled into the
ppp module to keep things simple. I'd still like to split them at a later
date, but that can be done when we have others things ready.

The basic problem I have is how do we configure the interface? How do we
control it?
I don't want to simply create a set of ppp entries at startup. I'd like to
be able to add/remove them as required. So if I ask for a pppoe interface I
get one. But of course I need to specify a username, password and possibly
also a service name to use, so how do we control the devices from the
kernel?

This is a piece of the man page for OpenBSD's pppoe...

EXAMPLE CONFIGURATION
     Given a machine with one Ethernet interface, xl0, the first thing that
     must be done is to bring the interface up:

           # ifconfig xl0 up
     This can be done automatically during boot with a /etc/hostname.xl0
file,
     see hostname.if(5) for details.

     Next, a /etc/ppp/ppp.conf file must be created.  Below is a minimal
PPPoE
     style configuration, see ppp(8) for more options.

           default:
              set log Phase Chat LCP IPCP CCP tun command

           pppoe:
              set device "!/usr/sbin/pppoe -i xl0"
              set mtu max 1492
              set mru max 1492
              set speed sync
              disable acfcomp protocomp
              deny acfcomp
              set authname "myUsername"
              set authkey "myPassword"

Hmm, lot's of questions. Anyone care to jump in with answers/suggestions ???


> > BTW, OpenBSD and FreeBSD have a pppoe server/client that I should be
> > able to use for testing of pppoe :) They manage it by using the
> > bpf device, which I don't really think is a good idea and I'd like
> > to do it differently.
>
> Hum, what is a "bpf" device!?
> Somethings we can si/emulate under BeOS, maybe?

bpf = berkely packet filter

Essentially it's a raw data interface and is used by the likes of tcpdump to
get at the packets. I don't really want to use it as it seems a "klunky" way
of doing pppoe, but may prove to be the only way :(

david

Other related posts: