QMI IPv6 crashes

[Dan Williams]

On Thu, 2014-04-24 at 20:48 +0200, Bjørn Mork wrote:
> 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?

Update on this.  I've tested a number of different devices with two
different SIMs where both carriers support IPv6.

Novatel USB551L + Verizon: V4V6 works fine
Novatel USB551L + T-Mobile: V4V6 crashes the modem
Huawei E398 + Verizon: V4V6 works fine
Huawei E398 + T-Mobile: V4V6 works fine
Sierra MC7750 + Verizon: V4V6 works fine in Windows
Sierra MC7750 + Verizon: V4V6 crashes modem in Linux

Not really sure what to make of it yet.

Dan