Re: WWAN, PPP, and IPv6 configuration questions

[Tore Anderson <tore fud no>]

* Dan Williams

> I eventually got it working for PPP and DHCP/SLAAC, using the
> dcbw/icera-ipv6 (ModemManager) and dcbw/wwan-ipv6 (NetworkManager)
> branches.

Cool! I'll try to give it a spin this weekend.

> NM will replace the IPv6 address set by pppd with the correct /64
> address.  It will then start RA on the interface and end up with the
> global IPv6 address.  Obviously as we've found before you'll need to
> hardcode the DNS servers since firmware doesn't proxy those into the
> RAs.

I think a better way than requiring hard-coded DNS servers would be to
have MM expose the network-provided DNS server as a bearer property,
which NM can then read and configure the system with.

Considering that MM already provides the network-provided Interface ID
to NM, this probably isn't too hard to implement, as MM will be able to
find the DNS server right alongside the Interface ID. For Icera, it will
be listed in output from AT%IPDPADDR? and for Ericsson it will be in
AT*IPCFG?, for example:

%IPDPADDR: 1, 188.149.56.47, 188.149.56.48, 188.149.250.18, 0.0.0.0, 0.0.0.0, 0.0.0.0, 255.255.0.0, 
188.149.56.48
%IPDPADDR: 1, 0.0.0.0, 0.0.0.0, 0.0.0.0, 0.0.0.0, 0.0.0.0, 0.0.0.0, 0.0.0.0, 0.0.0.0, fe80::3:a30d:3701, ::, 
2a00:e18:0:3::6, ::, ::, ::, ::, ::
%IPDPADDR: 1, 188.149.56.47, 188.149.56.48, 188.149.250.18, 0.0.0.0, 0.0.0.0, 0.0.0.0, 255.255.0.0, 
188.149.56.48, fe80::3:1f3:1501, ::, 2a00:e18:0:3::6, ::, ::, ::, ::, ::
*E2IPCFG: (1,"fe80:0000:0000:0000:0000:0006:9058:4701")(3,"2a00:0e18:0000:0003:0000:0000:0000:0006") 

These are the outputs from my Icera (PDP types IP, IPV6, and IPV4V6),
and from my Ericsson (PDP type IPV6), respectively. The DNS servers
provided by the network are 188.149.250.18 and 2a00:e18:0:3::6. The
fe80::* address is the network-provided LL address.

Interestingly, the "remote" LL address given by pppd is nowhere to
be found. I wonder if it might be something pppd (or the firmware)
invents on the spot. (In my case, I can ping *any* address in
fe80::/64, the network responds to them all.) If so that would
another argument for not using the "peer" construct when adding
the address to the interface.

Tore