core-admin/linux/system-config/vif-route-qubes

#!/bin/bash                              
#============================================================================
# /etc/xen/vif-route-qubes                                                   
#                                                                            
# Script for configuring a vif in routed mode.                               
# The hotplugging system will call this script if it is specified either in  
# the device configuration given to Xend, or the default Xend configuration  
# in /etc/xen/xend-config.sxp.  If the script is specified in neither of those
# places, then vif-bridge is the default.                                     
#                                                                             
# Usage:                                                                      
# vif-route (add|remove|online|offline)                                       
#                                                                             
# Environment vars:                                                           
# vif         vif interface name (required).                                  
# XENBUS_PATH path to this device's details in the XenStore (required).       
#                                                                             
# Read from the store:                                                        
# ip      list of IP networks for the vif, space-separated (default given in  
#         this script).                                                       
#============================================================================ 

dir=$(dirname "$0")
. "$dir/vif-common.sh"

#main_ip=$(dom0_ip)

case "$command" in
	online)
		ifconfig ${vif} up
		echo 1 >/proc/sys/net/ipv4/conf/${vif}/proxy_arp
		ipcmd='add'
		iptables_cmd='-I PREROUTING 1'
		cmdprefix=''
		;;
	offline)
		do_without_error ifdown ${vif}
		ipcmd='del'
		iptables_cmd='-D PREROUTING'
		cmdprefix='do_without_error'
		;;
esac

domid=${vif/vif/}
domid=${domid/.*/}
# metric must be possitive, but prefer later interface
#  32752 is max XID aka domid
metric=$[ 32752 - $domid ]

if [ "${ip}" ] ; then
	# If we've been given a list of IP addresses, then add routes from dom0 to
	# the guest using those addresses.
	for addr in ${ip} ; do
		${cmdprefix} ip route ${ipcmd} ${addr} dev ${vif} metric $metric
	done
	${cmdprefix} iptables -t raw $iptables_cmd -i ${vif} \! -s ${ip} -j DROP
	back_ip=${ip%.*}.1
	${cmdprefix} ip addr ${ipcmd} ${back_ip}/32 dev ${vif}
fi

log debug "Successful vif-route-qubes $command for $vif."
if [ "$command" = "online" ]
then
  success
fi