[PATCH] sim-qmi: load operator identifier and name from NAS home network

[Aleksander Morgado]

On Fri, Oct 23, 2015 at 12:13 AM, Dan Williams <dcbw at redhat.com> wrote:
> On Thu, 2015-10-22 at 23:30 +0200, Aleksander Morgado wrote:
>> On Thu, Oct 22, 2015 at 10:45 PM, Dan Williams <dcbw at redhat.com> wrote:
>> >> Being NAS commands, are these available also when not registered
>> >> anywhere? E.g. when in low-power mode?
>> >> I've seen people using these commands to retrieve SIM MCCMNC, but was
>> >> never sure about them as they were NAS and not DMS.
>> >
>> > Tried Gobi 1k and UML290; they both still return the home network when
>> > in low-power mode.  Also, the Gobi 1k didn't have any antennas connected
>> > and it still returned the right home network...
>>
>> Ah! good then.
>>
>> The issue with the MNC length (whether 2 or 3 digits) still affects
>> this implementation though. Actually, the implementation would not be
>> ok even for 2 digits, as it's not appending a leading 0 for
>> single-digit MNCs (e.g. "2141" instead of "21401"):
>>     operator_id = g_strdup_printf ("%" G_GUINT16_FORMAT "%"
>> G_GUINT16_FORMAT, mcc, mnc);
>> It should append leading 0s to the MNC based on whether the MNC is 2
>> or 3 digit long.
>
> Ah, good point.  I'd copied that from qmicli code and I guess it's wrong
> there, and I didn't catch it here either.
>
>> Now, there's a TLV 0x12 "3GPP Home Network MNC" in Get Home Network
>> that we didn't add yet to libqmi as far as I can tell. It consists of
>> a sequence of 2 bytes that are read as booleans:
>>   * 1st byte: whether the network is 3GPP.
>>   * 2nd byte: if 1st byte is true (net is 3GPP), whether the MNC is 3
>> digits long.
>>
>> Based on this, we could do:
>>   * If TLV 0x12 is available,  we already got told the MNC length and
>> we know how many 0s we need to prepend.
>>   * If TLV 0x12 is not available, we only print 3 digits if MNC is >99
>> and otherwise 2 digits always.
>> This logic is already what we do when building MCCMNC from current
>> serving system, as in common_process_serving_system_3gpp().
>
> Works for me, would you mind taking a stab at this?  I have to move on
> to other stuff tomorrow and early next week...

Sure, I'll try to do it myself during the weekend.

-- 
Aleksander
https://aleksander.es