Confirming APN in use

[Peter Naulls]

This is with ModemManager 1.18.6 and libqmi 1.30.4, but that I'm not necessarily 
tied to those, that's just what's in our stable code base. This is on OpenWrt 
22.03.

You'll also excuse the lack of detail in this; I don't think I need to report
here the actual APNs we're using here.

Now, when an APN is configured in OpenWrt, i.e,

uci show network.wwan.apn

ModemManager reports it's connecting to it:

netifd: wwan (5109): starting connection with apn ...

Now, this is *not* the APN reported in the "initial bearer apn" output,
nor is it the APNs output from the commands:  AT+CGCONTRDP or AT+CGDCONT?.

It is however, the APN reported by the bearer in use, bearer 1 in this case, and
that's what I'm picking up for my reporting.

So my question is, is this APN actually in use?  Is there a QMI query for this 
that ModemManager is using to check the modem with?

Or do I need an explicit setting of mmcli -m 0 
--3gpp-set-initial-eps-bearer-settings="apn=yourAPN" - I would assume this is 
not necessary, since it should all  be driven by the OpenWrt scripts.

Thanks!