- Can’t go home till the plumbing is done
… to get down and dirty with your wifi card. Really, get your mind out of the gutter. Lets keep this PG shall we?
The Wireless Summit, LinuxCon, and Linux Plumbers Conference were all two weeks ago, where the Wireless Cartel of Awesome met to unclog the drain of Linux wireless with the righteous hand of glory. We solved world peace while simultaneously making the earth safe for Democracy, David Zeuthen’s favorite pink pony, and a bunch of cute fuzzy kittens. But that’s boring. Instead, two other things deserve your attention:
Background Scanning
As of the 2.6.32 kernel WiFi scans requested while connected to an access point are background scans. The mac80211 stack will spread the scan out over about 30 seconds, jumping back to the associated AP’s channel every so often so it doesn’t stall your traffic. We’ve actually done this in the OLPC Libertas for a long time, and now everyone on the block gets it. There’s been any number of bugs open about NetworkManager’s scan behavior, including misguided requests for huge fat “Don’t scan while connected” checkboxes in the UI. And now that’s been fixed upstream. Oh, bought a Ralink card or a Broadcom? Sorry, better luck next time. This is why you buy hardware that actually works with Linux, so that the Gods of Kernel Wireless will rock your card, and you won’t be stuck with dead-end shit that never gets better. But maybe pain floats your boat. If you bought Intel or Atheros then you’re awesome.
Sometimes people stop me on the street and ask me why we want to scan periodically. Here’s what I tell them. Besides enabling location-based services (which help me find great candle-lit bistros for dates with your mom) there’s one super-important reason: roaming. Not just between networks, but also between APs in the same network. If the wifi card doesn’t have an up-to-date scan list, you’ll take the hit anyway at the worst possible moment: when your back is against the wall, the gun’s in your face, and you have to switch APs or lose the connection entirely. So better do it while you can. Only have one AP at your place and don’t need roaming? That’s nice, but writing software is about making things work smoothly for everybody. Which is what background scanning is all about.
wpa_supplicant D-Bus Interface 2.0
Over the summer, Witold Sowa rocked AP mode support in NetworkManager (though I still have to merge it), and as part of that hugely rewrote the D-Bus interface to wpa_supplicant that I wrote back in 2007. In conjunction with the upstream mac80211-based kernel drivers (sorry Broadcom and ralink, no soup for you) we’ll get better failure information, finer-grained control over wifi connections, faster reconnections, better handling of link dropouts, AP mode support, great roaming behavior, better power-saving for awesome netbook performance, and a lot of other stuff. Jouni already merged most of the supplicant patches so soon we’ll be rocking the wifi goodness bullet train.
And just one more thing…
Did somebody say Bluetooth DUN?
On different note, I did about 75% of the work to get bluetooth Dial-Up Networking support going this weekend. It’s too late to land in a 0.8 release later this month but first on the merge list for 0.8.1. Setup will be just as smooth as PAN setup, configuring your mobile broadband provider when you pair the phone and one-click connection after that. DUN gets requested a lot, and now with ModemManager backing our mobile broadband support, there’s enough flexibility to handle most of the really crappy phones out there. Honestly PAN just works better, but whatever.
More later. Peace out kids.