#!/bin/bash
#
# QEMU network configuration script to bring down tap devices. This
# utility needs to be run as root, and will use the tunctl binary
# from the native sysroot. 
#
# If you find yourself calling this script a lot, you can add the
# the following to your /etc/sudoers file to be able to run this
# command without entering your password each time:
#
# <my-username> ALL=NOPASSWD: /path/to/runqemu-ifup
# <my-username> ALL=NOPASSWD: /path/to/runqemu-ifdown
#
# Copyright (c) 2006-2011 Linux Foundation
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

usage() {
	echo "sudo $(basename $0) <tap-dev> <native-sysroot-basedir>"
}

if [ $EUID -ne 0 ]; then
	echo "Error: This script (runqemu-ifdown) must be run with root privileges"
	exit 1
fi

if [ $# -ne 2 ]; then
	usage
	exit 1
fi

TAP=$1
NATIVE_SYSROOT_DIR=$2

TUNCTL=$NATIVE_SYSROOT_DIR/usr/bin/tunctl
if [ ! -e "$TUNCTL" ]; then
	echo "Error: Unable to find tunctl binary in '$NATIVE_SYSROOT_DIR/usr/bin', please bitbake qemu-helper-native"
	exit 1
fi

$TUNCTL -d $TAP

# cleanup the remaining iptables rules
IPTABLES=`which iptables 2> /dev/null`
if [ "x$IPTABLES" = "x" ]; then
	IPTABLES=/sbin/iptables
fi
if [ ! -x "$IPTABLES" ]; then
	echo "$IPTABLES cannot be executed"
	exit 1
fi
n=$[ (`echo $TAP | sed 's/tap//'` * 2) + 1 ]
dest=$[ (`echo $TAP | sed 's/tap//'` * 2) + 2 ]
$IPTABLES -D POSTROUTING -t nat -j MASQUERADE -s 192.168.7.$n/32
$IPTABLES -D POSTROUTING -t nat -j MASQUERADE -s 192.168.7.$dest/32