net-partition

#!/bin/bash

# Use this to turn on or off blocking network traffic to IP address 127.0.0.2.

usage() {
  echo "Usage: $0 [on|off] - Turn on or off blocking network traffic to IP 127.0.0.2." ; exit 1
}

partitionOn() {
  if hash pfctl 2>/dev/null; then
    (pfctl -sr 2>/dev/null; echo "block drop quick proto tcp from 127.0.0.1 to 127.0.0.2") | pfctl -f - 2>/dev/null
    echo "Create partition between IP 127.0.0.1 and 127.0.0.2 (OSX)"
  elif hash iptables 2>/dev/null; then
    iptables -A INPUT -p tcp -s 127.0.0.1 -d 127.0.0.2 -j DROP
    echo "Create partition between IP 127.0.0.1 and 127.0.0.2 (Linux)"
  else
    echo "This command is currently only available on OSX or Linux systems."
    usage
  fi
}

partitionOff() {
  if hash pfctl 2>/dev/null; then
    pfctl -f /etc/pf.conf 2>/dev/null
    echo "Drop partition between IP 127.0.0.1 and 127.0.0.2 (OSX)"
  elif hash iptables 2>/dev/null; then
    iptables -D INPUT -p tcp -s 127.0.0.1 -d 127.0.0.2 -j DROP
    echo "Drop partition between IP 127.0.0.1 and 127.0.0.2 (Linux)"
  else
    echo "This command is currently only available on OSX or Linux systems."
    usage
  fi
}

if ! [ $(id -u) = 0 ]; then
  echo "Root user (sudo) required."
  exit 1
fi

arg=$1

case $arg in
  "on")
    partitionOn
    ;;
  "off")
    partitionOff
    ;;
  *)
    echo "Invalid subcommand '$arg', must be 'on' or 'off'"
    usage
    ;;
esac