redsocks-fw.sh

#!/bin/bash

set -eux -o pipefail

##########################
# Setup the Firewall rules
##########################
fw_setup() {
  # First we added a new chain called 'REDSOCKS' to the 'nat' table.
  iptables -t nat -N REDSOCKS

  # Next we used "-j RETURN" rules for the networks we don’t want to use a proxy.
  while read item; do
      iptables -t nat -A REDSOCKS -d $item -j RETURN
  done < /etc/redsocks-whitelist.txt

  # We then told iptables to redirect all port 80 connections to the http-relay redsocks port and all other connections to the http-connect redsocks port.
  iptables -t nat -A REDSOCKS -p tcp --dport 80 -j REDIRECT --to-ports 12345
  iptables -t nat -A REDSOCKS -p tcp -j REDIRECT --to-ports 12346

  # Finally we tell iptables to use the ‘REDSOCKS’ chain for all outgoing connection in the network interface ‘eth0′.
  iptables -t nat -A PREROUTING -i docker0 -p tcp -j REDSOCKS
}

##########################
# Clear the Firewall rules
##########################
fw_clear() {
  iptables-save | grep -v REDSOCKS | iptables-restore
}

case "$1" in
  start)
    echo -n "Setting REDSOCKS firewall rules..."
    fw_clear
    fw_setup
    echo "done."
    ;;
  stop)
    echo -n "Cleaning REDSOCKS firewall rules..."
    fw_clear
    echo "done."
    ;;
  *)
    echo "Usage: $0 {start|stop}"
    exit 1
    ;;
esac
exit 0