net_forward

#!/bin/sh

## hyphop ##

#= simple ip forward traffic manager linux example

BIN=$0
PROG=`basename $0`

permup(){

# need root perms
# or
# sudo ./sys_drop_cache

[ "$USER" != "root" ] && {
    echo "[i] sudo $BIN $@" >&2
    sudo "$BIN" "$@"
    exit 0
}

}

usage(){
    echo "$PROG - ip forward traffic manager
    usage: $PROG [ stop | start | status | help ]
    "
}

forward_start() {
    permup start
    [ "$1" ] || echo "[i] net_forward start" >&2
    echo 1 > /proc/sys/net/ipv4/ip_forward
    iptables -t nat -I POSTROUTING -j MASQUERADE
}

forward_stop() {
    permup stop
    [ "$1" ] || echo "[i] net_forward stop" >&2
    echo 0 > /proc/sys/net/ipv4/ip_forward
    iptables -t nat -D POSTROUTING -j MASQUERADE
}


forward_on=

forward_check() {
    forward_on=`cat /proc/sys/net/ipv4/ip_forward`
    [ "$1" ] || echo "[i] net_forward is: $forward_on" >&2
    return $forward_on
#    iptables -t nat -D POSTROUTING -j MASQUERADE
}


case "$1" in
    stop)
    forward_stop
    ;;
    start)
    forward_start
    ;;
    status)
    forward_check
    ;;
    help)
    usage
    ;;
    *)
    usage
    forward_check
esac