liberty.sh

#!/bin/sh -e
#
#  ~ liberty.sh ~
#
# Linux port of the Freedom network-disabling software for Mac & Win:
# http://macfreedom.com/
# 
# It is a Linux version of beloved Mac/Win software, therefore it is
# appropriately obscure and hard to use (but free!).
#
# Usage:
#
# Save this file to a directory on your computer, open a terminal, cd
# to the directory, chmod +x liberty.sh, and run it like so:
#
# $ sudo ./liberty.sh
#
# liberty.sh will prompt you for the length of time in minutes you'd
# like to be liberated from your Internet connection.
#
# If you'd like to have liberty.sh run without interactive prompting,
# you can simply pipe the number of minutes as standard input to
# liberty.sh:
#
# $ echo 60 | sudo ./liberty.sh
#
# You can also echo empty standard input and it will select a sensible
# default:
#
# $ echo | sudo ./liberty.sh
#
# You can confirm that liberty.sh is doing its thing by inspecting
# the iptables rules for the OUTPUT chain:
#
# $ sudo iptables -L -n
#
# liberty.sh creates two `at(1)' jobs to be run when the liberation
# time has expired. You can confirm this by typing:
#
# $ sudo atq
#
# liberty.sh doesn't disable *all* of your networking -- it leaves
# your loopback interface (lo0) alone, allowing you to continue to use
# the services on your local machine. You can keep developing that web 
# app without distraction.
#
# Note that your humble author has not actually *used* Freedom, so
# liberty.sh emulates only as many features as he could see from
# screenshots on the Freedom site (minus the GUI, of course!).

DEFAULT_MINUTES=45
MAX_MINUTES=480
MIN_MINUTES=15
IPTABLES_RULE="-j DROP"
# Uncomment the following if you'd prefer a less strict networking
# disabling that merely knocks out browsing to common WWW ports.
# IPTABLES_RULE="-p tcp -m multiport --dports 80,443 -j DROP"

if [ "$(id -u)" != "0" ]; then
    echo "Please run $0 as root (or sudo)." 1>&2
    exit 1
fi

prompt_minutes () {
    echo "How many minutes of liberty would you like?"
    echo "(default = $DEFAULT_MINUTES, minimum = $MIN_MINUTES, maximum = $MAX_MINUTES)"
    echo -n "Enter # of minutes: "
}

is_int () {
    test "$1" -eq "$1" >/dev/null 2>&1
}

echo
echo " ~ $(basename $0) will disable your Linux networking for up to 8 hours (480 minutes). ~"
echo
MINUTES=0
while :
do 
    prompt_minutes
    read MINUTES
    if is_int "$MINUTES"; then
	if [ "$MINUTES" -ge "$MIN_MINUTES" -a "$MINUTES" -le "$MAX_MINUTES" ]; then
	    break
	fi
    elif [ "x$MINUTES" = "x" ]; then
	MINUTES=$DEFAULT_MINUTES
	break
    fi
done
echo "iptables -D OUTPUT -d 127.0.0.1 -j ACCEPT" | at "now + $MINUTES minutes" >/dev/null 2>&1
echo "iptables -D OUTPUT $IPTABLES_RULE" | at "now + $MINUTES minutes" >/dev/null 2>&1
iptables -A OUTPUT -d 127.0.0.1 -j ACCEPT
iptables -A OUTPUT $IPTABLES_RULE
echo
echo "You've been liberated for the next $MINUTES minutes. Happiness."