Archive for May, 2007
Wireless Death Star
May 29th
OK this thing is a bit mad. If it’s real that is..
Mmm…spiky.
It’s called the Slurpr and it’s capable of combining up to six wireless networks into a single channel, effectively giving you one phat connection that hoses any open wireless in the vicinity. Of course these have to be unsecured networks – but the Slupr’s 266mhz processor and onboard memory opens up the possibility of cracking encryption such as WEP on the fly. Badass.
Xorg 7.2, modules sold separately
May 24th
Since it’s now officially in the FreeBSD ports tree, I decided to upgrade my work desktop to Xorg 7.2 today. The process is mostly painless as long as you are a good user and follow all the steps in /usr/ports/UPDATING – everyone reads that before upgrading anything, right?, right? 
The only gotcha I came across related to the modular nature of Xorg, mainly the “where’s my $DRIVER gone to?!” problem. To be honest I’d forgotten about this part even though 7.x has been out for a while, and I probably came across it on various Gentoo upgrades in the past. Running “startx” will simply dump you back out to the console with complaints about not being able to find your keyboard or mouse driver.
However it was pretty easy to infer what the problem was. In the caveats section of the Xorg UPDATING notes they mention you should probably have the x11/xorg meta-port installed. If you don’t have this installed (like me), it’s more than likely Xorg won’t start first go since it’s basically missing all the necessary modules required to load properly. So unless you don’t mind using X without luxuries like a keyboard or mouse you’d better install some drivers.
Luckily these are all packaged up nicely, I simply had to do:
portinstall x11-drivers/xf86-input-keyboard
portinstall xf86-input-mouse
portinstall xf86-video-ati*
* Replace that with your video card – you can probably guess the correct driver to install by looking at /usr/ports/x11-drivers
But..there was still another issue to tackle. Fonts. These are now also their own separate package. When starting X it appeared to get a little further, however it died just before loading the window manager with a message about not being able to find the “fixed” font. So, another portinstall was required:
portinstall xorg-fonts
3rd time lucky, now I have a working Xorg 7.2 install.
Followup to ng_fec saga
May 18th
So everything seems to have remained stable over the past few days – and theres now a commit to the ng_fec code:
Deadly! 
IPv6 and ng_fec
May 15th
We managed to finally (hopefully) fix an annoying problem with one of our FreeBSD boxes and IPv6.
For some background; we used the ng_fec (4) device on FreeBSD 6.2-RELEASE to make a logical network interface out of two physical interfaces. This is referred to as bonding on Linux, IP Multipathing on Solaris and I think Cisco call it Ether Channel. Whatever way you go about it, the end result is that you get a network interface that is reachable via a multiple different paths. If each physical interface is plugged into a different switch, you get a nice amount of resiliency.
This works great in FreeBSD with ng_fec, however if you try to use an IPv6 address on the logical interface thats where things start to get interesting. Without getting into too much detail – the problems relate to how IPv6 maps IP addresses to MAC addresses, this is done by way of “neighbour advertisement” messages sent via multicast. However the ng_fec driver was not telling the physical network interfaces to join the correct multicast groups so these neighbour advertisement messages could not be processed correctly, which led to very flaky and mostly unavailable IPv6 connectivity. From what I can gather, you can use other drivers in -CURRENT that don’t exhibit this problem.
But with some diagnoses and a patch to ng_fec.c from Dave Malone we managed to correct the issue. This may make it up into the FreeBSD source tree at some point.
Hopefully things will stay stable from now on
Edit: Ah, there is a bug report raised for this already.