Professional Geekism

I’ve been running a m0n0wall router for some time now. The build and design of the machine was meant to be documented on the ‘RoutITX’ page of this blog, but I’d never gotten around to finishing it off. I may do this now that I have more time, but I’m not promising anything…

Even so, due to the impressive compatibility of the Sony Ericsson K800i and Linux, and the subsequent lack of the same DHCP/CDC USB Ethernet adapter functionality in the K850i, I thought it’d be quite cool to see if the K800i could be configured as a back-up WAN interface within m0n0wall.

So I fish my K800i (now retired, although I wish it wasn’t) out of its resting place, find a USB cable, and plug it into the back of the m0n0wall machine. No new interface appeared on the ‘assign interfaces’ page, so I restarted it. Still no new interfaces. Upon checking the kernel messages in the log, I found these lines pertaining to the CDC USB Ethernet device:

Jan 4 20:28:06 kernel: device_attach: cdce0 attach returned 6
Jan 4 20:28:06 kernel: cdce0: could not find data bulk in
Jan 4 20:28:06 kernel: cdce0: Sony Ericsson Sony Ericsson K800, rev 2.00/0.00, addr 2

Which, as a Linux geek, confused me somewhat. Google turned up a number of results for ‘cdce0′ problems or ‘attach returned 6′ regarding various other drivers, but only one really addressed the issue in particular, albeit for a much older SE phone. You’ll notice that there haven’t been any replies, either.

A former colleague pointed me in the direction of a patch that was submitted around October 2008 which enables the proper handling of the CDC USB device within the Nokia N80. Hopefully it should help, but it may be some time before the patch filters down to m0n0wall.

This is just one of those times when I wish I’d followed the world of software development a little more.

I absolutely adored my Sony Ericsson K800i. What a phone; everyone’s had one or used one at some point. Given that they’re quite long in the tooth now, you’d be hard-pushed to have not come across someone that had/has one.

So when the K850i came out, I was quite eager to get my upgrade. And so far there’s been only one real drawback to it, that I’ve found: using it as a modem.

When I first moved into my current abode, I didn’t have any ADSL for a few weeks. Predictably one can steal some wireless broadband, or one can attempt to use some form of mobile broadband. Before signing my life away for a few months, I decided to test my phone (which at the time, was the K800i) with Ubuntu. To my sheer delight, the phone presents itself as a USB Ethernet adapter, and Ubuntu’s network-manager simply sent a DHCP request and received an ACK. No messing about here: I had 3G broadband within 5 seconds of plugging the USB cable in!

So obviously when I attempted the same trick with my K850i, I was really quite dismayed to find that you can’t do this any longer. The USB Ethernet device is there (grep -i CDC /var/log/messages) but for the life of me, I cannot find a way to obtain a DHCP lease via the usb0 interface.

Yes, it works perfectly (and with HSDPA speeds, thanks to my city-centre location) if you use wvdial or one of its GUI front-ends (gnome-ppp worked well) and I’ve been able to connect like this..

But I can’t understand why the Sony Ericsson engineers would want to remove such a simple mechanism in favour of the greatest faff-about in history. I’d be interested to hear from anyone that’s managed to get this working.. Although I fear by the time I get an answer, I’ll be back on some ADSL goodness: HSPDA is alright in a pinch, but T-Mobile UK’s data network seems so heavily sensitive to peak times (I suspect insane levels of contention) and the latency is atrocious. Half a second? Ugh. That’ll be the Deep Packet Inspection they do…