#!/bin/bash


# Establishment of a runtime environment for a
# virtual  machine  under QEMU, This script permits
# to the virtual machine to share the
# network connection with a host machine under FC6.

#Author: Amine chaoui

# Default Value
IP_GATEWAY=0.0.0.0
IP_HOST=0.0.0.0
IP_BROADCAST=0.0.0.0
IP_NETMASK=0.0.0.0

INTERFACE_LAN=eth0
INTERFACE_BRIDGE=br0
brctl=/usr/sbin/brctl

# Fonction de mise en place du pont
start () {
    #if we have already configured the same host_box no need to do it again
    set $(/sbin/ifconfig | grep $INTERFACE_BRIDGE) >/dev/null
    if [ -n "$1" ]; then
	echo "Interface bridge $INTERFACE_BRIDGE already exist."
	exit 0
    fi
    if [ -n "$1" ]; then
	INTERFACE_LAN=$1
	shift
    fi
    set $(/sbin/ifconfig | grep $INTERFACE_LAN) >/dev/null
    if [ -z "$1" ]; then
	echo "Interface réseau $IF_HOTE non trouvée."
	exit 1
    fi
    shift $(($# - 1))
    echo "Using the interface" $INTERFACE_LAN
	
    #Restarting the udev
    echo "Starting the udev ..."
    /sbin/udevd restart
    echo "Starting the kqemu patch module ..."
    modprobe kqemu
    #Loding the tun/tap model
    echo "Loading the kqemu patch module ..."
    modprobe kqemu
    #Loding the tun/tap model
    echo "Loading the tun module ..."
    modprobe tun
    set $(lsmod | grep tun) >/dev/null
    if [ -z "$1" ]; then
	echo "Module tun/tap not activated"
	exit 1
    fi
    shift $(($# - 1))

    #Giving acces in Read/Write to the tun module
    echo "Granting the Read/Write acces to the tun module..."
    chmod 666 /dev/net/tun


    ##Get The BROADCAST ip @
    set $(/sbin/ip addr show $INTERFACE_LAN | grep inet) >/dev/null 2>&1
    if [ -n "$2" ]; then
	IP_BROADCAST=$4
    fi
    shift $(($# - 1))
    
    #Getting the GATEWAY IP @
    set $(netstat -rn | grep UG ) >/dev/null 2>&1
    if [ -n "$2" ]; then
	IP_GATEWAY=$2
    fi
    shift $(($# - 1))

    #Getting the host IP
    set $(ifconfig $INTERFACE_LAN 2> /dev/null | grep "inet addr:" | \
	sed -e "s/.*addr:\([^ ]*\).*/\1/")
    if [ -n "$1" ]; then
	IP_HOST=$1
    fi
    shift $(($# - 1))
 
    ##Getting the Netmask address
    set $(ifconfig $INTERFACE_LAN 2> /dev/null | grep "inet addr:" | \
	sed -e "s/.*Mask:\([^ ]*\).*/\1/")
    if [ -n "$1" ]; then
	IP_NETMASK=$1
    fi
    shift $(($# - 1))
    #check if the module brctl is there
    if  [ ! -e $brctl ] ; then
	echo "Module Brctl  '/usr/sbin/brctl' is not found"
	exit 0
    fi
    # Création et paramétrage du pont
    echo "Configure $INTERFACE_BRIDGE bridge..."
    $brctl addbr $INTERFACE_BRIDGE
    #/usr/sbin/brctl stp $INTERFACE_BRIDGE yes
    $brctl addif $INTERFACE_BRIDGE $INTERFACE_LAN
    echo "Activating promiscuous mode  $INTERFACE_LAN..."
    /sbin/ifconfig $INTERFACE_LAN 0.0.0.0 promisc up
    sleep 2
    echo "IP address on $INTERFACE_BRIDGE..."
    # static
    /sbin/ifconfig $INTERFACE_BRIDGE $IP_HOST  broadcast $IP_BROADCAST  netmask $IP_NETMASK up
    sleep 1
	
    #Reconfigure the Bridge IP @ in the host machine
    echo "Configuring  the IP  Gateway @:" $IP_GATEWAY
    route add default gw $IP_GATEWAY

    
    #wipe the host firewall otherwise the guest qemu can't acces to the LAN
    echo "Wiping the firewall..." 
    iptables -F
    
}


#Adding a new interface to the bridge
add () {
        /sbin/ifconfig $1 0.0.0.0 promisc up
        /usr/sbin/brctl addif $INTERFACE_BRIDGE $1
}


#Stop the actual bridged network  and Restore the original network
stop () {
        if [ -n "$1" ]; then
                INTERFACE_LAN=$1
        fi
        TESTPONT=$(/sbin/ifconfig | grep $INTERFACE_BRIDGE)
        if [ -z "$TESTPONT" ]; then
                echo "Attention : pont réseau non trouvé. Vérifier la config réseau ..."
                exit 1
        fi
        #check if the module brctl is there
	if [  ! -e $brctl  ] ;then
	    echo "Module Brctl  '/usr/sbin/brctl' is not found"
	    exit 0
	fi
        $brctl delif $INTERFACE_BRIDGE $INTERFACE_LAN
        /sbin/ifconfig $INTERFACE_BRIDGE down
        $brctl delbr $INTERFACE_BRIDGE
        /sbin/service network restart
}

# 
case $1 in
        start)
                start $2
        ;;
        stop)
                stop $2
        ;;
        add)
                add $2
        ;;
        *)
                echo $"Use: env-qemu {start|add|stop} [interface]"
                exit 1
esac

exit 0