Re: u-blox R410M modem (QMI) configuration with modern Network-manager

[Tim Harvey <tharvey gateworks com>]

On Fri, Nov 30, 2018 at 12:26 PM Dan Williams <dcbw redhat com> wrote:
> On Fri, 2018-11-30 at 11:24 -0800, Tim Harvey wrote:
> > On Fri, Nov 30, 2018 at 3:12 AM Aleksander Morgado
> > <aleksander aleksander es> wrote:
> > > Hey,
> > >
> > > > I'm trying to use a u-blox QMI R410M with network manager on
> > > > Ubuntu
> > > > bionic witht he following which works fine on Ubuntu xenial:
> > > >
> > > > # nmcli connection add type gsm ifname cdc-wdm0 con-name mymodem
> > > > apn $APN
> > > > # nmcli connection up id mymodem
> > > >
> > > > The modem's QMI interface is indeed /dev/cdc-wdm0, my APN is
> > > > correct,
> > > > and I can connect just fine using mmcli or qmicli directly.
> > > >
> > > > On Xenial with network-manager-1.2.6 this works fine but on
> > > > Bionic
> > > > with network-manager-1.10.6 this results in 'Error: Connection
> > > > activation failed: No suitable device found for this
> > > > connection.'.
> > > >
> > > > I'm thinking the connection configuration syntax has likely
> > > > changed
> > > > I'm I'm simply using the wrong syntax?
> > > >
> > > > Note that I'm using libqmi-1.20.2 and modemmanager-1.8.2 from
> > > > Aleksander's Ubuntu PPA's in both cases.
> > >
> > > I'm not totally sure what might have changed in NM, but have you
> > > tried
> > > creating the connection *without ifname*?
> > > You can have "gsm" connection settings not bound any interface, NM
> > > will try to find a suitable device when connecting.
> >
> > hmm... I wonder if that's not available until a newer version of NM?
> >
> > root@bionic-newport:~# nmcli --version
> > nmcli tool, version 1.10.6
> > root@bionic-newport:~# nmcli connection add type gsm con-name mymodem
> > apn $APN
> > Error: 'ifname' argument is required.
>
> Yeah, that's a bug in nmcli:
>
> https://bugzilla.gnome.org/show_bug.cgi?id=780323
>
> I think you can delete the ifname after you create the connection
> though.

Dan,

Thomas' suggestion of using 'nmcli connection add type gsm con-name
mymodem apn $APN ifname ''' works to create the connection without
'interface-name' being defined in
/etc/NetworkManager/system-connections/* but when I try to bring up
the connection I get an error still:

root@bionic-newport:~# nmcli connection add type gsm con-name mymodem
apn $APN ifname '*'
Connection 'mymodem' (8596b198-9c03-434f-a4b7-b1e2048ae032) successfully added.
root@bionic-newport:~# cat /etc/NetworkManager/system-connections/mymodem
[connection]
id=mymodem
uuid=2cd6c189-b8c1-4b41-8688-465651e25703
type=gsm
permissions=

[gsm]
apn=NIMBLINK.GW12.VZWENTP
number=*99#

[ipv4]
dns-search=
method=auto

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
method=auto
root@bionic-newport:~# nmcli connection up id mymodem
Error: Connection activation failed: No suitable device found for this
connection.

> > I've always thought the 'gsm' and 'cdma' types are a bit outdated for
> > modern LTE modems but it looks like that is what your supposed to
> > continue using according to the NM docs.
>
> These days "gsm" means any GSM, UMTS, and LTE provider, even if the LTE
> provider still runs a CDMA network. The modem hides the details of CDMA
> for you. We may be able to deprecate it in a few years when most of the
> CDMA/EVDO networks are shut down.
>
> The NM distinction for cdma & gsm existed before LTE was a thing, and
> NM values backwards compatibility, so it's still there.

ok - thanks for the explanation

> > I wonder if there is something wrong with NM here as it doesn't even
> > seem to be even managing my wired connections:
>
> IIRC on Ubuntu (and perhaps Debian?) if you have anything in
> /etc/network/interfaces, then the distro configures NM to ignore those
> interfaces.  I think if you remove anything related to eth0 from /e/n/i
> then NM will be able to manage them.

hmmm... so removing all eth0 from /etc/network/interfaces and
restarting NM didn't automatically create a connection for it like I'm
used to seeing on Xenial and adding it manually results in the same
'No suitable device found for this conneciotn.' error:
root@bionic-newport:~# nmcli connection add type ethernet ifname eth0
con-name 'Wired connection 1'
Connection 'Wired connection 1' (14d7ee2a-b340-49df-9937-28baca8918c3)
successfully added.
root@bionic-newport:~# nmcli connection up id 'Wired connection 1'
Error: Connection activation failed: No suitable device found for this
connection.
root@bionic-newport:~# ifconfig
lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 100  bytes 6548 (6.5 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 100  bytes 6548 (6.5 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Tim