#!/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.
#
#
# 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