[PATCH 0/3] Enabling IPv6 on Qualcomm MDM9x00 chipsets

[Bjørn Mork]

Dan Williams <dcbw at redhat.com> writes:

> So this NV item is actually called NV_IPV6_ENABLED_I, which is pretty
> telling.  And it's only one byte in length too.

You have documentation for the NV items?  Is that available to the
public somewhere?

>> Note that if you have an IPv6 *only* SIM, like I have, then you also
>> have to change the PDP type of the default profile to IPV6 and restart
>> the modem.  Else it won't work.  The same goes for IPv4 *only* SIMs,
>> actually: If the default profile has a type different from IP, then
>> the modem will fail to attach to the network.
>
> Does this still hold for IPV4V6, if the modem supports it?  Or is it
> only a problem with SIM:IPv6 & PDP:IPV4 and vice versa?

You tell me. I don't know.  Currently I have a number of IPv4 only SIMs,
and one IPv6 only SIM.  I do not have any SIM allowing dual stack IPV4V6
connections.

>From what I understand, there is some doubt about IPV4V6 among
operators. If you depend on that type, then you prevent roaming in
networks which does not support it, IIUC.  And there are still a few of
those around the world.

So the operators seem to be more interested in NAT64/DNS64/464XLAT
solutions using IPV6 only PDP contexts than true dual stack solutions.
It does make some sense, given that most of them would use NATed RFC1918
addresses for the IPv4 part of the IPV4V6 context anyway.

But that's probably because they don't care at all about IPv6 in mobile
broadband devices yet


>> So how do you find your default profile?  It's often the first one,
>> listed as 1 in the output from AT+CGDCONT?.  So an easy way to change
>> it to IPV6 is by using the AT command interface:
>> 
>>  AT+CGDCONT=1,"IPV6"
>> 
>> You can verify that this in fact changed the default by using qmicli:
>> 
>>  bjorn at nemi:~$ qmicli -d /dev/cdc-wdm0 --wds-get-default-settings=3gpp
>>  Default settings retrieved:
>>          APN: ''
>>          PDP type: 'ipv6'
>>          Username: ''
>>          Password: ''
>>          Auth: 'none'
>> 
>> 
>> I hope this helps documenting yet another piece of undocumented
>> magic in these Qualcomm firmwares.  You gotta wonder what they smoked
>> the day they decided to disable IPv6 by default...
>
> Well, I'm sure there's documentation in the Qualcomm ICDs and under
> NDA :)  But we certainly don't have any of that.  The NV item
> provisioning is under the control of the OEM or the provider during
> provisioning, so the best guess is that the OEM either just didn't
> bother to set it, since they didn't care about IPv6, or they actually
> don't want to support it, or they are relying on provider-specific
> connection software to make the change when needed.

You are probably right.  It doesn't make any sense to me, but that seems
to be the way they think.  "Let's just make sure things fail in subtle
and random ways.  That will save us from supporting it.  IPv6 is an
advanced feature which noone needs.  We can always fix this in the next
batch"


Bjørn