pflightbar#

A little utility for OpenBSD on the Chromebook Pixel to flash the lightbar red when pf blocks a packet. (Demo)

Usage#

Make sure the pflog0 device exists (usually created by /etc/rc.d/pflogd) and that blocked traffic is sent to it via a pf rule:

block return log

Then just run pflightbar & as root. It will initialize the pcap device, open /dev/chromeec, chroot to /var/empty and then drop privileges to nobody.

pflightbar will load some "lightbyte" byte code into the lightbar's program sequence to flash red through a full ramp up and back down. This is used to minimize communication with the EC when flashing, rather than having to send the full RGB and dim sequences every time.

When a blocked packet is sent to pflog0, pflightbar will see it and tell the lightbar to run the program sequence to flash red, and then return to its normal (S0) sequence.