#!/bin/bash # # QEMU network interface configuration script. This utility needs to # be run as root, and will use the tunctl binary from a native sysroot. # Note: many Linux distros these days still use an older version of # tunctl which does not support the group permissions option, hence # the need to use build system's version. # # 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 # # If you'd like to create a bank of tap devices at once, you should use # the runqemu-gen-tapdevs script instead. If tap devices are set up using # that script, the runqemu script will never end up calling this # script. # # 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) <uid> <gid> <native-sysroot-basedir>" } if [ $EUID -ne 0 ]; then echo "Error: This script (runqemu-ifup) must be run with root privileges" exit 1 fi if [ $# -ne 3 ]; then usage exit 1 fi USERID="-u $1" GROUP="-g $2" NATIVE_SYSROOT_DIR=$3 TUNCTL=$NATIVE_SYSROOT_DIR/usr/bin/tunctl if [ ! -x "$TUNCTL" ]; then echo "Error: Unable to find tunctl binary in '$NATIVE_SYSROOT_DIR/usr/bin'" exit 1 fi TAP=`$TUNCTL -b $GROUP 2>&1` STATUS=$? if [ $STATUS -ne 0 ]; then # If tunctl -g fails, try using tunctl -u, for older host kernels # which do not support the TUNSETGROUP ioctl TAP=`$TUNCTL -b $USERID 2>&1` STATUS=$? if [ $STATUS -ne 0 ]; then echo "tunctl failed:" exit 1 fi fi IFCONFIG=`which ip 2> /dev/null` if [ "x$IFCONFIG" = "x" ]; then # better than nothing... IFCONFIG=/sbin/ip fi if [ ! -x "$IFCONFIG" ]; then echo "$IFCONFIG cannot be executed" exit 1 fi 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 ] $IFCONFIG addr add 192.168.7.$n/32 broadcast 192.168.7.255 dev $TAP $IFCONFIG link set dev $TAP up dest=$[ (`echo $TAP | sed 's/tap//'` * 2) + 2 ] $IFCONFIG route add to 192.168.7.$dest dev $TAP # setup NAT for tap0 interface to have internet access in QEMU $IPTABLES -A POSTROUTING -t nat -j MASQUERADE -s 192.168.7.$n/32 $IPTABLES -A POSTROUTING -t nat -j MASQUERADE -s 192.168.7.$dest/32 echo 1 > /proc/sys/net/ipv4/ip_forward echo 1 > /proc/sys/net/ipv4/conf/$TAP/proxy_arp $IPTABLES -P FORWARD ACCEPT echo $TAP