Re: [PATCH 2/3] ADSL: Carrier Handling and PPP support

[David Woodhouse <dwmw2 infradead org>]

On Sat, 2011-05-21 at 10:03 +0300, Pantelis Koukousoulas wrote:
> Well, the reason that I didn't try to implement IPv6 in the first
> version is that unfortunately my provider still doesn't support it,
> so I wouldn't be able to test if it works :(

:(

> Is it true that pretty much the only thing needed for IPv6 is to
> add the "ipv6" option to pppd? (plus any networkmanager
> specific stuff that may be needed).

It would be 'ipv6 ,' because the 'ipv6' option takes a parameter for the
local and remote interface identifier.

That just negotiates link-local IPv6 addresses though. To get the
*global* address (and subnet for routing) you have to do something else.
That can either be a PPP extension or DHCPv6; I think the latter is
favoured.

I can give access to an l2tp connection to someone who seriously wants
to work on this.

> If it is like this, it won't be hard to add support so that you can
> test the code and maybe also look into adding this to the other
> ppp links as well.
> 
> 
> >> +             vpi = nm_setting_adsl_get_vpi (adsl_pppoa);
> >> +             vci = nm_setting_adsl_get_vci (adsl_pppoa);
> >> +             encapsulation = nm_setting_adsl_get_encapsulation (adsl_pppoa);
> >> +             vpivci = g_strdup_printf("%s.%s", vpi, vci);
> >
> > You want to specify device number there, not just assume there's only
> > one. There are dual-port PCI ADSL cards that work quite nicely in
> > Linux...
> 
> I see, you mean like 0.8.35 and 1.8.35 for the second port.
> I will try to fix this.

I talked to Dan on IRC about this; it requires a patch like the one at
http://bigw.org/~dan/atm-ifindex.patch (which I've now tested and it
seems fine:
[root@solos ~]# grep ^ /sys/class/atm/*/atmindex
/sys/class/atm/solos-pci0/atmindex:  0
/sys/class/atm/solos-pci1/atmindex:  1

However, it does have leading whitespace in the 'atmindex' file which I
wasn't expecting. Was that intentional, Dan?)

> I posted a "proof of concept" implementation of PPPoE patch in this list:
> http://www.mail-archive.com/networkmanager-list gnome org/msg17967.html
> 
> Could you take a look? This was just enough code to get me a
> successful PPPoE connection, but with your help/advise I could
> improve it to be more generally useful :)

You are hard-coding the name 'nas0' for the virtual Ethernet interface,
which you shouldn't. And I think I'd be tempted not to use the separate
br2684ctl program; the amount of code you have to 'manage' the external
tool *far* exceeds the amount of relevant code in br2684ctl.c itself :)

> >> +             nm_cmd_line_add_string (cmd, "noipdefault");
> >
> > Why's that unconditional? Do we not have the option to set static IP
> > addresses on a PPP connection? It's useful in some cases.
> 
> My impression is that NetworkManager wants it this way, it gets the IP
> that the provider assigns but this doesn't mean it will actually set
> this IP, if you say that you want a static IP it will use the one you
> provide instead.

Hm, OK. Although in PPP you're supposed to *tell* the other side what IP
address you're using in a ConfReq packet.

-- 
dwmw2