NDISDUP+wwan for Huawei devices using the new 'huawei_cdc_ncm' driver

[Dan Williams]

On Mon, 2013-12-02 at 10:17 -0600, Dan Williams wrote:
> On Fri, 2013-11-29 at 19:51 +0100, Bjørn Mork wrote:
> > Bjørn Mork <bjorn at mork.no> writes:
> > 
> > >> Also note that only 36xx and 55xx modules have *E2IPCFG; the 3507 does
> > >> not.  We didn't bother with E2IPCFG in ModemManager because the modules
> > >> support DHCP.  Unfortunately there's nobody from ericsson around anymore
> > >> to tell us about IPv6...
> > >
> > > I have a F3507g and H5321gw (NCM only and not upgradable) too.  Will
> > > test them if/when I can find the time.
> > 
> > I am probably doing something wrong.  I have the same problem with both
> > the F3507g and the H5321gw: No RAs, no DHCPv6, and AT*E2IPCFG only
> > gives a LL address (only on the H5321gw of course - the F3507g doesn't
> > support this command as you noted).  And I cannot find any way to use
> > this LL address.
> 
> I tried the 3607gw and could only get an IPv6 address once.  The other
> times I got disconnected immediately after being disconnected
> ("AT*E2NAP: 0,36").  I think this device has older firmware, but I've
> never been able to upgrade it, since it's a Toshiba module but I don't
> have a Toshiba, and thus haven't ever gotten Windows drivers to
> recognize the device.
> 
> But here's what I did with the 5521gw:
> 
> ifconfig wwan1 up
> wireshark on wwan1
> AT+CFUN=1
> AT+CGDCONT=3,"IPV6","epc.tmobile.com"  (firmware doesn't support IPV4V6)
> AT*E2NAP=1  (for connection notifications)
> (wwan1 has no IP addresses yet)
> AT*ENAP=1,3
> 
> wait for AT*E2NAP: 1 response, then boom wireshark finds some packets.
> They are:
> 
> :: -> ff02::1:ffec:200  Neighbor solicitation for feec:200
> feec:200 -> ff02::2     Router solicitation from 02:80:37:ec:02:00
> feec:200 -> ff02::2     Router solicitation from 02:80:37:ec:02:00
> feec:201 -> ffec:200    Router advertisement from 02:80:37:ec:02:01
> 
> AT*E2IPCFG?
> *E2IPCFG:
> (1,"fe80:0000:0000:0000:0000:0022:b2d6:8101"),(3,"fd00:976a:0000:0000:0000:0000:0000:0009")
> 
> ifconfig wwan1 gives me:
> inet6 2607:fb90:17:540c:80:37ff:feec:200/64
> inet6 fe80::80:37ff:feec:200/64
> ether 02:80:37:ec:02:00
> 
> The router advertisement isn't very interesting, except that it does
> have the O bit set (no other bits set), router lifetime 65535, Prefix
> information 2607:fb90:17:540c::/64, and the A flag set.  Lifetimes for
> the prefix are set to infinity.  Source link-layer address is
> 02:80:37:ec:02:01.
> 
> Then I tried to go to www.google.com, and the module crashed.
> 
> So anyway, you are correct, it doesn't appear that the module cares at
> all about the IPv6LL address that it reports with E2IPCFG.
> 
> > I observed one very strange thing on the F3507g: It sends gratious ARPs
> > for an IPv4 LL address when an IPV6 PDP type connection is established.
> > That was a bit surprising.
> 
> I see the gratuitous ARPs too.

Oh, I should note that for whatever reason, I wasn't able to get DHCPv6
responses on the 5521 at all; I did make sure the firewall was flushed
for IPv6, but no replies from the module.  I was using the "-S" option
to do Information-Only queries.  I tried both with and the
module-supplied LL address and without, no luck.  Not sure what's going
on with that.

Dan