#!/bin/sh
#
# Copyright (c) 2010, Yavuz Gokirmak
#
# All rights reserved.
#
# This source code may be used, modified, copied, distributed, and
# sold, in both source and binary form provided that the above
# copyright and these terms are retained, verbatim, as the first
# lines of this file. Under no circumstances is the author
# responsible for the proper functioning of the software nor does
# the author assume any responsibility for damages incurred with
# its use.
#
# $FreeBSD$
#
# This script adds virtual nodes to one of the physical interfaces
# visible on your local area network (LAN). Virtual nodes seems real
# to external observers.
# If traceroute is executed to one of virtual nodes, the IP
# address of the physical interface will not be seen in the output.
# Virtual nodes are generated via jails and network connections are
# established using ng_bridge(4) and ng_eiface(4) node types.
#
# To use this script:
#
# 0. Make your own copy of this example script.
#
# 1. Edit the definition of ${ETHER_INTF} as described below
# to define your real interface connected to the LAN. Virtual nodes
# will placed on the same physical network as this interface.
#
# 2. Edit the definition of ${TARGET_TOPOLOGY} to define your virtual
# nodes. Virtual topology definition includes node names and their
# IP address. Target top. syntax: ( node1|ip1/24 node2|ip2/24 ... )
# Example 1: ( n1|122.122.122.12/24, n2|122.122.122.13/24 ...)
# Example 2: ( n1|2001:b90::14a/125, n1|2001:b90::14b/125 ...)
#
# 3. Run this script with "start" as the command line argument.
#
# 4. Stop bridging by running this script with "stop" as the
# command line argument.
#
# 5. This script uses a template file in order to carry information
# between start and stop calls.
# In the start call, the netgraph interfaces and jails are created.
# At the stop phase, all created objects should be removed.
# DO NOT delete the temporary file between the start and stop phases.
#
# To add virtual nodes for multiple independent LANs, create multiple
# copies of this script with different variable definitions.
#
# Target Topology:
#
#
# +---------------+ +---------------+ +---------------+
# | n0 (vimage) | | n1 (vimage) | | nk (vimage) |
# | | | | | |
# | +-----------+ | | +-----------+ | | +-----------+ |
# | | ngeth0 | | | | ngeth1 | | | | ngethk | |
# | |(ng_eiface)| | | |(ng_eiface)| | | |(ng_eiface)| |
# | +--+-----+--+ | | +--+-----+--+ | | +--+-----+--+ |
# | |ether| | | |ether| | | |ether| |
# | +--X--+ | | +--X--+ | | +---X-+ |
# +-----+ +--------\------+ +--------\------+ +-------/-------+
# |upper|----\ \ip_addr \ip_addr /ip_addr
# +-+-----+--+ \ \ \ \
# | em0 | \ +--------+ +-+ \
# |(ng_ether)| +-----------+ \ \ \
# +-+-----+--+ \ \ / \
# |lower| +---------\ \ \ / /
# +--X--+ / O--X--O O-X---O O---X-O O--X--O O---X---O
# \ | |link0| |link1| |link2| |link3| |linkk+2|
# \ / +-O-----O-O-----O-O-----O-O-----O-----O-------O-+
# +---+ | |
# | bridge (ng_bridge) |
# +-----------------------------------------------+
#
#
# Give the name of ethernet interface. Virtual nodes will be seen as
# local neighbours of this interface.
ETHER_INTF="em0"
# List the names of virtual nodes and their IP addresses. Use ':'
# character to separate node name from node IP address and netmask.
TARGET_TOPOLOGY="c1|10.0.2.20/24 c2|10.0.2.21/24 c3|10.0.2.22/24"
# MAC manufacturer prefix. This can be modified according to needs.
MAC_PREFIX="00:1d:92"
# Temporary file is important for proper execution of script.
TEMP_FILE="/var/tmp/.virtual.lan.tmp"
# Set root directory for jails to be created.
JAIL_PATH="/usr/jails/node"
####################################################################
#### Nothing below this point should need to be modified. ####
####################################################################
# Start/restart routine.
virtual_lan_start() {
# Load netgraph KLD's as necessary.
for KLD in ng_ether ng_bridge ng_eiface; do
if ! kldstat -v | grep -qw ${KLD}; then
echo -n "Loading ${KLD}.ko... "
kldload ${KLD} || exit 1
echo "done"
fi
done
# Reset all interfaces and jails. If temporary file can not be found
# script assumes that there is no previous configuration.
if [ ! -e ${TEMP_FILE} ]; then
echo "No previous configuration(${TEMP_FILE}) found to clean-up."
else
echo -n "Cleaning previous configuration..."
virtual_lan_stop
echo "done"
fi
# Create temporary file for usage. This file includes generated
# interface names and jail names. All bridges, interfaces and jails
# are written to file while created. In clean-up process written
# objects are cleaned (i.e. removed) from system.
if [ -e ${TEMP_FILE} ]; then
touch ${TEMP_FILE}
fi
echo -n "Verifying ethernet interface existence..."
# Verify ethernet interface exist.
if ! ngctl info ${ETHER_INTF}: >/dev/null 2>&1; then
echo "Error: interface ${ETHER_INTF} does not exist"
exit 1
fi
ifconfig ${ETHER_INTF} up || exit 1
echo "done"
# Get current number of bridge interfaces in the system. This number
# is used to create a name for new bridge.
BRIDGE_COUNT=`ngctl l | grep bridge | wc -l | sed -e "s/ //g"`
BRIDGE_NAME="bridge${BRIDGE_COUNT}"
# Create new ng_bridge(4) node and attach it to the ethernet interface.
# Connect ng_ether:lower hook to bridge:link0 when creating bridge and
# connect ng_ether:upper hook to bridge:link1 after bridge name is set.
echo "Creating bridge interface: ${BRIDGE_NAME}..."
ngctl mkpeer ${ETHER_INTF}: bridge lower link0 || exit 1
ngctl name ${ETHER_INTF}:lower ${BRIDGE_NAME} || exit 1
ngctl connect ${ETHER_INTF}: ${BRIDGE_NAME}: upper link1 || exit 1
echo "Bridge ${BRIDGE_NAME} is created and ${ETHER_INTF} is connected."
# In the above code block two hooks are connected to bridge interface,
# therefore LINKNUM is set to 2 indicating total number of connected
# hooks on the bridge interface.
LINKNUM=2
# Write name of the bridge to temp file. Clean-up procedure will use
# this name to shutdown bridge interface.
echo "bridge ${BRIDGE_NAME}" > ${TEMP_FILE}
# Attach other interfaces as well.
for NODE in ${TARGET_TOPOLOGY}; do
# Virtual nodes are defined in TARGET_TOPOLOGY variable. They
# have the form of 'nodeName|IPaddr'. Below two lines split
# node definition to get node name and node IP.
NODE_NAME=`echo ${NODE} | awk -F"|" '{print $1}'`
NODE_IP=`echo ${NODE} | awk -F"|" '{print $2}'`
# Create virtual node (jail) with given name and using
# JAIL_PATH as root directory for jail.
echo -n "Creating virtual node (jail) ${NODE_NAME}..."
jail -c vnet name=${NODE_NAME} host.hostname=${NODE_NAME} \
path=${JAIL_PATH} persist
echo "done"
# Write name of the jail to temp file. Clean-up procedure will
# use this name to remove jail.
echo "node ${NODE_NAME}" >> ${TEMP_FILE}
# Create a ng_eiface object for virtual node. ng_eiface
# object has a hook that can be connected to one of bridge
# links. After creating interface get its automatically
# generated name for further usage.
echo "Creating eiface interface for virtual node ${NODE_NAME}."
ngctl mkpeer eiface ether ether
EIFACE=`ngctl l | grep ngeth | tail -n 1| awk '{print $2}'`
echo "Interface ${EIFACE} is created."
# Write name of the interface to temp file. Clean-up procedure
# will use this name to shutdown interface.
echo "interface ${EIFACE}" >> ${TEMP_FILE}
# Move virtual interface to virtual node. Note that Interface
# name will not be changed at the end of this movement. Moved
# interface can be seen at the output of ifconfig command in
# jail: 'jexec jailname ifconfig'
echo "Moving ${EIFACE} to ${NODE_NAME}"
ifconfig ${EIFACE} vnet ${NODE_NAME}
# Make lo0 interface localhost.
jexec ${NODE_NAME} ifconfig lo0 localhost
# Generate a random mac address for virtual interface. First
# three octets can be changed by user. Last three octets are
# generated randomly.
M4=`od -An -N2 -i /dev/random | sed -e 's/ //g' | \
awk '{ print $1 % 256 }'`
M5=`od -An -N2 -i /dev/random | sed -e 's/ //g' | \
awk '{ print $1 % 256 }'`
M6=`od -An -N2 -i /dev/random | sed -e 's/ //g' | \
awk '{ print $1 % 256 }'`
MAC=`printf ${MAC_PREFIX}:%02x:%02x:%02x ${M4} ${M5} ${M6}`
# Set the link address (mac address) of virtual interface in
# virtual node to randomly generated MAC.
echo "Setting MAC address of ${EIFACE} to '${MAC}'"
jexec ${NODE_NAME} ifconfig ${EIFACE} link $MAC
# Either IPv4 or IPv6 can be used in this script. Ifconfig
# IP setting syntax differs slightly for two IP versions.
# For version 4 'inet' keyword is used whereas for version 6
# 'inet6' is used. Below line tries to decide which IP version
# is given and sets IPVER to 'inet' or 'inet6'.
IPVER=`echo ${NODE_IP} | awk -F"." '{ split($4,last,"/"); \
if( NF==4 && $1>0 && $1<256 && $2<256 && $3<256 && \
last[1]<256) print "inet"; else print "inet6"}'`
# Set IP address of virtual interface in virtual node.
echo "Setting IP address of ${EIFACE} to '${NODE_IP}'"
jexec ${NODE_NAME} ifconfig ${EIFACE} ${IPVER} ${NODE_IP}
# Connect virtual interface to bridge interface. Syntax is :
# ngctl connect INTERFACE: BRIDGE: INTERFACE_HOOK EMPTY_LINK.
# Interface has one hook named 'ether' and below line connects
# ether hook to bridge's first unconnected link.
echo -n "Connecting ${EIFACE}:ether to ${BRIDGE_NAME}:link${LINKNUM}..."
ngctl connect ${EIFACE}: ${BRIDGE_NAME}: ether link${LINKNUM} \
|| exit 1
echo "done"
# Now, bridge has one more connected link thus link count is
# incremented.
LINKNUM=`expr ${LINKNUM} + 1`
done
echo "Virtual LAN established successfully!"
}
# Stop routine.
virtual_lan_stop() {
if [ ! -e ${TEMP_FILE} ]; then
echo "Nothing to stop! ${TEMP_FILE}: temp file not found"
else
echo -n "Shutdown bridge interface.."
OBJECTS=`cat ${TEMP_FILE} | grep bridge | awk '{print $2}'`
for BRIDGE in ${OBJECTS}; do
ngctl shutdown ${BRIDGE}: >/dev/null 2>&1
done
echo "done"
echo -n "Shutdown all eiface interfaces..."
OBJECTS=`cat ${TEMP_FILE} | grep interface | awk '{print $2}'`
for INTERFACE in ${OBJECTS}; do
ngctl shutdown ${INTERFACE}: >/dev/null 2>&1
done
echo "done"
echo -n "Removing all jails..."
OBJECTS=`cat ${TEMP_FILE} | grep node | awk '{print $2}'`
for NODE in ${OBJECTS}; do
jail -r ${NODE}
done
echo "done"
echo "Removing tempfile ${TEMP_FILE}"
rm ${TEMP_FILE}
fi
echo "Virtual LAN objects removed successfully!"
}
virtual_lan_usage() {
echo "usage: $0 start [target_topology]"
echo " : $0 [ stop | help ]"
}
# Main entry point.
case $# in
1)
case $1 in
start)
echo -n "Creating default target topology:"
echo " ${TARGET_TOPOLOGY}"
virtual_lan_start
;;
stop)
if [ ! -e ${TEMP_FILE} ]; then
echo -n "Noting to stop! ${TEMP_FILE}:"
echo " temp file not found"
else
virtual_lan_stop
fi
;;
help)
virtual_lan_usage
exit 1
;;
*)
virtual_lan_usage
exit 1
esac
;;
2)
case $1 in
start)
TARGET_TOPOLOGY=$2
echo -n "Creating target topology:"
echo "${TARGET_TOPOLOGY}"
virtual_lan_start
;;
*)
virtual_lan_usage
exit 1
esac
;;
*)
virtual_lan_usage
exit 1
esac