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executable file 92 lines (80 sloc) 1.81 KB
#!/bin/bash
# qemu-ifup script for QEMU/KVM with NAT netowrk mode
# set your bridge name
BRIDGE=virbr0
# Network information
NETWORK=192.168.122.0
NETMASK=255.255.255.0
# GATEWAY for internal guests is the bridge in host
GATEWAY=192.168.122.1
DHCPRANGE=192.168.122.2,192.168.122.254
# Optionally parameters to enable PXE support
TFTPROOT=
BOOTP=
function check_bridge()
{
if brctl show | grep "^$BRIDGE" &> /dev/null; then
return 1
else
return 0
fi
}
function create_bridge()
{
brctl addbr "$BRIDGE"
brctl stp "$BRIDGE" on
brctl setfd "$BRIDGE" 0
ifconfig "$BRIDGE" "$GATEWAY" netmask "$NETMASK" up
}
function enable_ip_forward()
{
echo 1 > /proc/sys/net/ipv4/ip_forward
}
function add_filter_rules()
{
iptables -t nat -A POSTROUTING -s "$NETWORK"/"$NETMASK" \
! -d "$NETWORK"/"$NETMASK" -j MASQUERADE
}
function start_dnsmasq()
{
# don't run dnsmasq repeatedly
ps -ef | grep "dnsmasq" | grep -v "grep" &> /dev/null
if [ $? -eq 0 ]; then
echo "Warning:dnsmasq is already running. No need to run it again."
return 1
fi
dnsmasq \
--strict-order \
--except-interface=lo \
--interface=$BRIDGE \
--listen-address=$GATEWAY \
--bind-interfaces \
--dhcp-range=$DHCPRANGE \
--conf-file="" \
--pid-file=/var/run/qemu-dnsmasq-$BRIDGE.pid \
--dhcp-leasefile=/var/run/qemu-dnsmasq-$BRIDGE.leases \
--dhcp-no-override \
${TFTPROOT:+"--enable-tftp"} \
${TFTPROOT:+"--tftp-root=$TFTPROOT"} \
${BOOTP:+"--dhcp-boot=$BOOTP"}
}
function setup_bridge_nat()
{
check_bridge "$BRIDGE"
if [ $? -eq 0 ]; then
create_bridge
fi
enable_ip_forward
add_filter_rules "$BRIDGE"
start_dnsmasq "$BRIDGE"
}
# need to check $1 arg before setup
if [ -n "$1" ]; then
setup_bridge_nat
ifconfig "$1" 0.0.0.0 up
brctl addif "$BRIDGE" "$1"
exit 0
else
echo "Error: no interface specified."
exit 1
fi