QMI IPv6 crashes

[Bjørn Mork]

Dan Williams <dcbw at redhat.com> writes:

> Hi,
>
> I did some testing with the UML290 on both Verizon (LTE) and T-Mobile
> (UMTS) and got odd results from GetCurrentSettings, and couldn't get any
> connectivity:
>
> [mm-bearer-qmi.c:382] get_ipv6_config(): QMI IPv6 Settings:
> [mm-bearer-qmi.c:393] get_ipv6_config():     Address: 2600:1014:b005:6ff1:7824:b541:88db:58c8/64
> [mm-bearer-qmi.c:399] get_ipv6_config():     Gateway: d42f:cc9d:967a:4442::
> [mm-bearer-qmi.c:410] get_ipv6_config():     DNS #1: 2001:4888:3a:ff00:304:d::
> [mm-bearer-qmi.c:421] get_ipv6_config():     DNS #2: 2001:4888:39:ff00:308:d::
>
> This matches the raw QMI output, eg:
>
>>>>>>>   type       = "IPv6 Secondary DNS Address" (0x28)
>>>>>>>   length     = 16
>>>>>>>   value      = 20:01:48:88:00:39:FF:00:03:08:00:0D:00:00:00:00
>>>>>>>   translated = { [0] = '8193 ' [1] = '18568 ' [2] = '57 ' [3] =
> '65280 ' [4] = '776 ' [5] = '13 ' [6] = '0 ' [7] = '0 '}
>
> Now what is up with that...  neither the gateway nor the DNS servers are
> actually valid IPv6 addresses?  Clearly stuff didn't work.

Huh? The DNS server addresses look both valid and reasonable to me.
2001:4888::/32 is allocated to Verizon, and there is nothing technically
wrong with those addresses - is there?

The gateway looks suspicious though.  It is in a reserved part of the
address space:
http://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xhtml
I guess it could work nontheless, as long as the modem responds to NS
for that address and the host doesn't sanity check it.  But it makes
more sense using some other address pointing to the modem, if you can.
Or try disabling ARP (i.e. ND) and just point the default route to the
wwan0 device.

Maybe using the RAs at least for the default route makes more sense?
That's what you'll do in almost every other case.  Or doesn't the modem
respond to RS? Do you see any other IPv6 packets from the modem?


Bjørn