(For Linux users, make sure you have oathtool and openconnect, then start from Step 6. If you don't have a token secret key, have a friend generate one for you on OSX via steps 3-5)
Get homebrew and install oath-toolkit, openconnect, and tuntap.
And follow the additional tuntap installation instructions!
After the tuntap module is installed, reboot or use kextload to activate it.