#!/bin/bash

lan_interface=en0
wan_interface=en1
lan_ip=192.168.0.1



if [ $# -eq 0 ] ; then
    "$0" start
else
    while [ $# -gt 0 ] ; do
        case "$1" in

            status)

                echo lan_interface $lan_interface
                echo wan_interface $wan_interface

                ps ax | grep -e 'nat[d]'
                ifconfig ${wan_interface}
                ifconfig ${lan_interface}
                ipfw list
                sysctl net.inet.ip.forwarding
                sysctl net.inet.ip.fw.enable

                ;;

            start)

                ifconfig ${lan_interface} down
                ifconfig ${lan_interface} ${lan_ip} netmask 255.255.255.0 up

                sysctl -w net.inet.ip.forwarding=1

                killall natd
                natd -interface ${wan_interface} -dynamic

                ipfw -f flush
                ipfw add divert natd all from any to any via ${wan_interface}
                ipfw add pass all from any to any
                ipfw list

                sysctl -w net.inet.ip.fw.enable=1

                ;;

            lan-ip)
                shift
                lan_ip="$1"
                ;;

            wan-interface|interface)

                shift
                wan_interface="$1"

                ;;

            lan-interface)

                shift
                lan_interface="$1"

                ;;

            *)

                printf "%s usage:\n\n" "$(basename "$0")"
                printf '    %s [wan-interface|interface $if] [lan-interface $if] [lan-ip $ip] [start] [status] \n\n' "$(basename "$0")"
                exit 64

                ;;

        esac
        shift
    done
fi
exit 0