Re: ANN: NetworkManager 1.0.0 released!

[Aleksander Morgado <aleksander aleksander es>]

On Sun, Dec 21, 2014 at 12:15 PM, Tore Anderson <tore fud no> wrote:
> > This release brings [...] WWAN IPv6 support
>
> Before you rush off to upload 1.0.0 to the various distros, I'd like to
> remind you of https://bugzilla.gnome.org/show_bug.cgi?id=733696. This
> is going to break WWAN connections for quite a few people, and they
> will need manual configuration to recover.
>
> The problem is that NetworkManager 1.0.0 will, when everything is left
> at its defaults, attempt to use the dual-stack IPV4V6 PDP context type
> if ModemManager reports that the modem supports it. This is a sane
> thing to do by default, I think. However - even if the modem supports
> it, the network operator might not. If so, the network attachment will
> fail. Since NM doesn't retry with IP[v4] and/or IPV6, this failure is
> final and the user is left without network connectivity. In order to
> force IPv4-only connections, the user must manually disable IPv6 (and
> vice versa).
>
> This will happens for standard WWAN connections where the user goes
> through the «Set up a Mobile Broadband Connection» wizard, changing as
> little as possible - including any connections created in this way in
> previous NM versions. That means that for users who upgrade to NM
> 1.0.0, previously working connection profiles will break.

Are you suggesting that by default NM should try with IPv4 or IPv6 PDP
context types if both are enabled and IPV4V6 fails?
In QMI modems it is ModemManager the one connecting separately IPv4
and IPv6 WDS sessions when IPv4v6 is requested.

> This issue is aggravated by the fact that ModemManager will advertise
> IPV4V6 support for all MBIM modems (even if the modem doesn't support
> it, which I believe is the case for the vast majority of 3G modems),
> see
> http://cgit.freedesktop.org/ModemManager/ModemManager/tree/src/mm-broadband-modem-mbim.c#n486.
> That makes NM always try IPV4V6, but if the modem doesn't support it,
> MM will immediately fail with the error "NoDeviceSupport". So if the
> user has a MBIM modem that doesn't support IPV4V6, NM 1.0.0 will break
> regardless of what the network provider supports.

Unfortunately I don't know of any command that we could use to query
the MBIM modem of supported IP types.

If MBIM modems do not always handle IPv4v6 PDP context types, and if
there is no MBIM command to ask for that, should we instead default to
not showing IPv4v6 as supported?

-- 
Aleksander
https://aleksander.es