#!/bin/sh
# Filename:      grml-router
# Purpose:       set up your box as NAT-router
# Authors:       grml-team (grml.org), Ulrich Dangel <schula@grml.org>, Michael Prokop <mika@grml.org>
# Bug-Reports:   see http://grml.org/bugs/
# License:       This file is licensed under the GPL v2.
# Latest change: Sam Okt 07 23:18:38 CEST 2006 [mika]
################################################################################

# exit on any error
set -e

CONFIG_FILE=/etc/grml/routersetup
. /etc/grml/lsb-functions
. /etc/grml/net-functions
. /etc/grml/script-functions

if [ $UID != 0 ]; then
   eerror "Error: become root before starting $0"
   exit 100
fi

if ! [ -r $CONFIG_FILE ] ; then
  eerror "$CONFIG_FILE could not be read."
  exit 1
fi

. $CONFIG_FILE

if [ -z "$OUTDEV" ] ; then
    eewarn "Outgoing device is not set in $CONFIG_FILE"
    eewarn "Setting Outgoing device to auto"
    OUTDEV=auto
fi

case "$OUTDEV" in
    auto|default)
    OUTDEV=$(defaultGWDev)
    if [ -z "$OUTDEV" ] ; then
	    eerror "The outgoing device could not be determined."
	    eerror "Please adjust OUTDEV in $CONFIG_FILE"
	    exit 1
    fi
    ;;
esac

[ -n "$IPTABLES" ] || IPTABLES=/sbin/iptables

check4progs $IPTABLES || exit 1

case "$1" in
    start)
        einfo "Adjusting kernel variables (net.ipv4.*)"
          sysctl -w net.ipv4.conf.all.rp_filter=1    1>/dev/null && \
          sysctl -w net.ipv4.conf.all.log_martians=1 1>/dev/null && \
          sysctl -w net.ipv4.ip_forward=1            1>/dev/null
        eend $?
        einfo "Setting up iptables rule"
          eindent

            einfo "Adding masquarade rule"
            $IPTABLES -t nat -A POSTROUTING -o $OUTDEV -j MASQUERADE
            eend $?
          eoutdent
   ;;

   stop)
       einfo "Resetting kernel variables"
         sysctl -w net.ipv4.ip_forward=0            1>/dev/null && \
         sysctl -w net.ipv4.conf.all.log_martians=0 1>/dev/null
       eend $?

       einfo "Removing iptables rule"
         $IPTABLES -t nat -D POSTROUTING -o $OUTDEV -j MASQUERADE
       eend $?
   ;;

   restart)
        $0 stop
        sleep 1
        $0 start
   ;;

   info)
    einfo "$0 - script which turns on router capabilities (NAT)"
    einfo "Configure it via $CONFIG_FILE" ; eend 0
   ;;

   *)
    echo "Usage: $0 {start|stop|restart|info}"
    exit 1
   ;;
esac

## END OF FILE #################################################################
# vim: ft=sh expandtab ai