#!/bin/bash
# Generate interface files for a dumbbell topology (as well as some special cases)
#
# Read the comments in this script or the help for details.
# For more info see: http://sandilands.info/sgordon/virtnet
#
# $Revision$
# $Author$
# $Date$
# $URL$

# Default values
lefthosts=1
righthosts=0
routers=0
topology="100"
outdir="./"
createnodelist=0
drawfig=0
drawdot=0

function usage {
	echo "Usage: vn-generatedumbbell [OPTIONS]..."
	echo "Generate interface files for virtnet for dumbbell-like topology"
	echo " "
	echo "OPTIONS"
	echo "Options may take either a long form (--long) or short form (-l). Options"
	echo "with parameters have a space between the option and parameter. The"
	echo "options available are [default values in square brackets]:"
	echo "  -t, --topology NUM    number to be assigned to the created topology [100]"
	echo "  -l, --lefthosts NUM   number of hosts on left of dumbbell [1]"
	echo "  -r, --righthosts NUM  number of hosts on right of dumbbell [0]"
	echo "  -R, --routers NUM     number of routers in middle of dumbbell [0]"
	echo "  -n, --nodelist        if set, create a node list file [not set]"
	echo "  -d, --drawdot         if set, create a dot figure of topology [not set]"
	echo "  -o, --out DIR         save all output files in directory DIR [./]"
	echo " "
	echo "EXAMPLES"
	echo "1. LAN of 5 hosts, no routers (not really dumbbell)"
	echo "   vn-generatedumbbell -l 5"
	echo " "
	echo "2. Chain topology with 3 routers and hosts on either end; dot file output"
	echo "   vn-generatedumbbell -l 1 -R 3 -r 1 -d"
	echo " "
	echo "3. Dumbbell (uneven); node list file also created"
	echo "   vn-generatedumbbell -l 3 -R 4 -r 2 -n -o ../../data/interfaces"
	echo " "
	echo "4. Multiple clients, single server; topology 101"
	echo "   vn-generatedumbbell -l 10 -R 1 -r 1 -t 101"
	echo " "
	echo "Some special cases/rules:"
	echo " - if 0 routers are specified, then all right hosts will be transferred"
	echo "   to become left hosts, e.g. -l 3 -R 0 -r 2 will produce -l 5"
	echo " - topologies may have 0 left and/or right hosts if at least 1 router"
	echo " "
	echo "OUTPUT"
	echo "The primary output is a set of interface files, one per node in the"
	echo "topology, the can then be used with vn-createtopology to create a virtnet"
	echo "network. An explanation of the interface files and their format can be"
	echo "found in ../../data/topologies/README.txt"
	echo " "
	echo "If the --nodelist option is used, a text file containing the list of nodes,"
	echo "their names and IP addresses, is also created. This can be used by other"
	echo "virtnet scripts, e.g. vn-applycmd to apply commands to only the hosts."
	echo " "
	echo "If the --drawdot option is used, then two .dot files will be created, "
	echo "which then can be used by 'dot' (part of GraphViz) to create an image"
	echo "showing the topology. The files are named:"
	echo "  virtnet-topology-NUM-named.dot"
	echo "  virtnet-topology-NUM-nodes.dot"
	echo "where the named file includes node names such as left1, router2, sw1"
	echo "and the nodes file includes node numbers such as 1, 2, 3. If 'dot' is"
	echo "installed these files can be used to produce images such as PNG by:"
	echo "  dot -Tpng virtnet-topology-NUM-named.dot > virtnet-topology-NUM-named.png"
	echo " "
	echo "TODO"
	echo "Add option for ring topology, connecting first router with last."
}

# Read input parameters
while [ "$1" != "" ]; do
        case $1 in
                -l | --lefthosts )   shift;
                                lefthosts=$1;
                                ;;
                -r | --righthosts )  shift;
                                righthosts=$1;
                                ;;
                -R | --routers )  shift;
                                routers=$1;
                                ;;
		-n | --nodelist ) createnodelist=1;
				;;
		-f | --drawfig ) drawfig=1;
				;;
		-d | --drawdot ) drawdot=1;
				;;
                -t | --topology )  shift;
                                topology=$1;
                                ;;
                -o | --out )    shift;
                                outdir=$1;
                                ;;
                * )             usage
                                exit 1
        esac
        shift
done

# If no routers, then  must be a LAN. Join the left and right hosts.
if [ "${routers}" = "0" ]; then
	lefthosts=$(( ${lefthosts} + ${righthosts} ));
	righthosts=0
fi

# If only routers (no left or right hosts) then create a ring
if [ "${lefthosts}" = "0" -a "${righthosts}" = "0" ]; then
	if [ "${routers}" = "0" ]; then
		echo "You cannot have 0 hosts and 0 routers."
		echo "Exiting."
		exit 1
	else
		specialcase="ring"
	fi
fi

# Topology parameters
numnetworks=$(( ${routers} + 1));
totalnodes=$(( ${lefthosts} + ${routers} + ${righthosts} ));
firstrouter=$(( ${lefthosts} + 1 ));
lastrouter=$(( ${lefthosts} + ${routers} ));
netnumber=1

# Address structure
# Ip addresses are split into parts:
# commonnetwork - subnet - hostbase - hostspecific
# where
# commonnetwork is the same for all networks, e.g. 192.168.
commonnetwork="192.168."
# subnet is an integer, incremented for each subnet
subnet=1
# hostbase is 1 for left hosts
lefthostbase=1
# and 2 or higher for right hosts
righthostbase=2
# hostspecific is an integer, increment for each host in the subnet
hostspecific=1
#
# The result is address such as:
# lefthosts: 192.168.1.11, 192.168.1.12, 192.168.1.13, ... , 192.168.1.20, ...
# righthosts: 192.168.x.21, 192.168.x.22, 192.168.x.23, ..., 192.168.x.30, ...
# router1: 192.168.1.1, 192.168.2.1
# router2: 192.168.2.2, 192.168.3.2
# router3: 192.168.3.3, 192.168.4.3
# routerN: 192.168.N.N, 192.168.(N+1).N
# Other addresses used:
netmask="255.255.255.0"
defaultnetwork="${commonnetwork}0.0"
defaultnetmask="255.255.0.0"

# Check the limits 
# Currently there is a limit on the number of networks/routers supported
# since the router addressing scheme will overlap with host addressing 
# scheme in the right network. This is limited by righthostbase. 
# To lift this limit, increase righthostbase parameter above.
limitrouters=$(( ${righthostbase} * 10 - 1 ));
if [ ${routers} -gt ${limitrouters} ]; then
    echo "vn: The number of routers you selected (${routers}) creates"
    echo "vn: too many networks such that there will be a conflict"
    echo "vn: in addresses assigned to hosts and routers. The"
    echo "vn: current limit is ${limitrouters}. Either reduce the"
    echo "vn: number of routers, or modify this script and increase"
    echo "vn: righthostbase."
    echo "vn: Error. Address conflict due to too many routers. Exiting."
    exit 1
fi


# Currently there is a limit on the number of networks/routers supported
# since networks are named a, b, c, d, ... .
# To lift this limit, need to modify the naming scheme, e.g. a, b, ... z, aa, ab, ...
limitnetworks=26
if [ ${numnetworks} -gt ${limitnetworks} ]; then
    echo "vn: The number of routers you selected (${routers}) creates"
    echo "vn: more than the supported number of networks (${limitnetworks})."
    echo "vn: Please try again with less routers (or change this script"
    echo "vn: to support more networks)".
    echo "vn: Error. Too many routers. Exiting."
    exit 1
fi

# DOT figure
if [ "${drawdot}" = "1" ]; then
	dotfilenamed="${outdir}/virtnet-topology-${topology}-named.dot"
	dotfilenodes="${outdir}/virtnet-topology-${topology}-nodes.dot"
	echo "graph topology${topology} {" | tee ${dotfilenamed} ${dotfilenodes} > /dev/null
	echo "rankdir=LR" | tee -a ${dotfilenamed} ${dotfilenodes} > /dev/null
	echo "node [shape=rectangle,width=0.5,height=0.5]" | tee -a ${dotfilenamed} ${dotfilenodes} > /dev/null
	echo "s1 [shape=rectangle,width=0.3,height=0.15,label=\"sw\"]" >> ${dotfilenamed}
	echo "s2 [shape=rectangle,width=0.3,height=0.15,label=\"sw\"]" >> ${dotfilenamed}
	echo "s1 [shape=rectangle,width=0.3,height=0.15,label=\"\"]" >> ${dotfilenodes}
	echo "s2 [shape=rectangle,width=0.3,height=0.15,label=\"\"]" >> ${dotfilenodes}
fi

# Create the interfaces for each node
for (( node=1; node<=${totalnodes}; node++ ));
do
	# Node number in text format
	noden=${node}
	if [ ${noden} -lt 10 ]; then
		noden="0${noden}";
	fi

	# Name of interface file
	nodeiffile="${outdir}/interfaces-topology-${topology}-node-${noden}"

	# IP addresses
	# Left hosts
	if [ ${node} -lt ${firstrouter} ]; then
	    nodetype="host"
	    hostaddress=$(( ${lefthostbase} * 10 + ${node} ));
	    ipaddress="${commonnetwork}${subnet}.${hostaddress}";
	    netaddress="${commonnetwork}${subnet}.0"
	    bcaddress="${commonnetwork}${subnet}.255"
	    defaultrouter="${commonnetwork}${subnet}.1"
		nodename="left${node}"

		# DOT figure
		if [ "${drawdot}" = "1" ]; then
			echo "${nodename} -- s1" >> ${dotfilenamed}
			echo "${node} -- s1" >> ${dotfilenodes}
			dotlastnode="s1"
			dotlastnum="s1"
		fi

	# Right hosts
	elif [ ${node} -gt ${lastrouter} ]; then
	    nodetype="host"
	    hostaddress=$(( ${righthostbase} * 10 + ${node} - ${lefthosts} - ${routers} ));
	    ipaddress="${commonnetwork}${subnet}.${hostaddress}";
	    routerhostportion=$(( ${subnet} - 1 ));
	    defaultrouter="${commonnetwork}${subnet}.${routerhostportion}"
		nodename="right$(( ${node} - ${lefthosts} - ${routers} ))"

		# DOT figure
		if [ "${drawdot}" = "1" ]; then
			if [ ${node} -eq $(( ${lastrouter} + 1 )) ]; then
				echo "${dotlastnode} -- s2" >> ${dotfilenamed}
				echo "${dotlastnum} -- s2" >> ${dotfilenodes}
			fi
			echo "s2 -- ${nodename}" >> ${dotfilenamed}
			echo "s2 -- ${node}" >> ${dotfilenodes}
		fi
	# Routers
	else
	    nodetype="router"
	    routernum=$(( ${node} - ${lefthosts} ));
	    ipaddress="${commonnetwork}${subnet}.${routernum}"
	    subnet2=$(( ${subnet} + 1 ));
	    ipaddress2="${commonnetwork}${subnet2}.${routernum}"
            netaddress2="${commonnetwork}${subnet2}.0"
	    bcaddress2="${commonnetwork}${subnet2}.255"
		nodename="router$(( ${node} - ${lefthosts} ))"

		# DOT figure
		if [ "${drawdot}" = "1" ]; then
			echo "${dotlastnode} -- ${nodename}" >> ${dotfilenamed}
			echo "${dotlastnum} -- ${node}" >> ${dotfilenodes}
			dotlastnode=${nodename}
			dotlastnum=${node}
		fi
	fi
        netaddress="${commonnetwork}${subnet}.0"
	bcaddress="${commonnetwork}${subnet}.255"

	# Output node list
	if [ "${createnodelist}" = "1" ]; then
		nodelistfile="${outdir}/nodelist-topology-${topology}"
		echo "${node},${nodename},${ipaddress}" >> ${nodelistfile}
	fi


	# Convert subnet number into name, e.g. "1" to "neta"
	subnetnum=$(( ${subnet} + 96 ));
	subnetletter=`printf "\x$(printf %x $subnetnum)"`;
	vboxnet="net${subnetletter}"
	if [ "${nodetype}" = "router" ]; then
	    subnet2num=$(( ${subnet2} + 96 ));
	    subnet2letter=`printf "\x$(printf %x $subnet2num)"`;
	    vboxnet2="net${subnet2letter}"
	fi

	echo "# Interface file auto-generated by vn-generateinterfaces" > ${nodeiffile}
	echo "auto lo" >> ${nodeiffile}
	echo "iface lo inet loopback" >> ${nodeiffile}
	echo " " >> ${nodeiffile}
	echo "auto eth0" >> ${nodeiffile}
	echo "iface eth0 inet dhcp" >> ${nodeiffile}
	echo " " >> ${nodeiffile}
	echo "# VBoxNetwork: ${vboxnet}" >> ${nodeiffile}
	echo "auto eth1" >> ${nodeiffile}
	echo "iface eth1 inet static" >> ${nodeiffile}
	echo -e "\taddress ${ipaddress}" >> ${nodeiffile}
	echo -e "\tnetmask ${netmask}" >> ${nodeiffile}
	echo -e "\tnetwork ${netaddress}" >> ${nodeiffile}
	echo -e "\tbroadcast ${bcaddress}" >> ${nodeiffile}

	# Host node
	if [ "${nodetype}" = "host" ]; then
		echo -e "\tpost-up route add -net ${defaultnetwork} netmask ${defaultnetmask} gw ${defaultrouter} dev eth1" >> ${nodeiffile}
		echo -e "\tpre-down route del -net ${defaultnetwork} netmask ${defaultnetmask} gw ${defaultrouter} dev eth1" >> ${nodeiffile}
	# Router node
	else
	    # In a chain such as:
	    # H1 - R1 - R2 - R3 - R4 - R5 - H2
	    # we will treat R1, R2 and R3 as left side routers, and R4 and R5 as right side
	    # Left side routers will have:
	    # - default route to rest of network on eth2 (right side of router)
	    # - specific routes to subnets on left of it on eth1
	    # Note that we don't need to add specific routes for directly attached networks
	    # as they are automatically created when the interface is brought up.
	    # For example R2 will have:
	    # - default route to 192.168.0.0 to gw R3 on eth2
	    # - specific router to 192.168.1.0 (H1-R1) to gw R1 on eth1
	    # Similar applies for right side routers, but in the opposite direction:
	    # - default route to rest of network on eth1 (left side of router)
	    # - specific routes to subnets on right of it on eth2

		firstrouternum=1
		midrouternum=$(( (${routers} + 1) / 2 ));
		lastrouternum=${routers}
		# Left side routers
		if [ ${routernum} -le ${midrouternum} ]; then
		    # Add 'numsr' specific routes on 1st interface
		    numsr=$(( ${routernum} - ${firstrouternum} ));
		    for (( sr=1; sr<=${numsr}; sr++ )); do
			destnetwork="${commonnetwork}${sr}.0"
			destmask=${netmask}
			destgw="${commonnetwork}${subnet}.$(( ${subnet} - 1 ))"
			destif="eth1"
			echo -e "\tpost-up route add -net ${destnetwork} netmask ${destmask} gw ${destgw} dev ${destif}" >> ${nodeiffile}
			echo -e "\tpre-down route add -net ${destnetwork} netmask ${destmask} gw ${destgw} dev ${destif}" >> ${nodeiffile}
		    done

	            # Create 2nd interface on router
		    echo " " >> ${nodeiffile}
		    echo "# VBoxNetwork: ${vboxnet2}" >> ${nodeiffile}
		    echo "auto eth2" >> ${nodeiffile}
		    echo "iface eth2 inet static" >> ${nodeiffile}
		    echo -e "\taddress ${ipaddress2}" >> ${nodeiffile}
		    echo -e "\tnetmask ${netmask}" >> ${nodeiffile}
		    echo -e "\tnetwork ${netaddress2}" >> ${nodeiffile}
		    echo -e "\tbroadcast ${bcaddress2}" >> ${nodeiffile}

		    # Add default route on 2nd interface
		    if [ ${routers} -gt 1 ]; then
			defaultgw="${commonnetwork}$(( ${subnet} + 1 )).$(( ${subnet} + 1 ))";
			defaultif="eth2"
			echo -e "\tpost-up route add -net ${defaultnetwork} netmask ${defaultnetmask} gw ${defaultgw} dev ${defaultif}" >> ${nodeiffile}
			echo -e "\tpre-down route add -net ${defaultnetwork} netmask ${defaultnetmask} gw ${defaultgw} dev ${defaultif}" >> ${nodeiffile}
		    fi

		# Right side routers
		else
		    # Add default route on 1st interface
		    defaultgw="${commonnetwork}${subnet}.$(( ${subnet} - 1 ))";
		    defaultif="eth1"
		    echo -e "\tpost-up route add -net ${defaultnetwork} netmask ${defaultnetmask} gw ${defaultgw} dev ${defaultif}" >> ${nodeiffile}
		    echo -e "\tpre-down route add -net ${defaultnetwork} netmask ${defaultnetmask} gw ${defaultgw} dev ${defaultif}" >> ${nodeiffile}

	            # Create 2nd interface on router
		    echo " " >> ${nodeiffile}
		    echo "# VBoxNetwork: ${vboxnet2}" >> ${nodeiffile}
		    echo "auto eth2" >> ${nodeiffile}
		    echo "iface eth2 inet static" >> ${nodeiffile}
		    echo -e "\taddress ${ipaddress2}" >> ${nodeiffile}
		    echo -e "\tnetmask ${netmask}" >> ${nodeiffile}
		    echo -e "\tnetwork ${netaddress2}" >> ${nodeiffile}
		    echo -e "\tbroadcast ${bcaddress2}" >> ${nodeiffile}

		    # Add 'numsr' specific routes on 2nd interface
		    numsr=$(( ${lastrouternum} - ${routernum} ));
		    for (( sr=${numsr}; sr>=1; sr-- )); do
			destnetwork="${commonnetwork}$(( ${subnet} + 1 + ${sr} )).0"
			destmask=${netmask}
			destgw="${commonnetwork}$(( ${subnet} + 1 )).$(( ${subnet} + 1 ))"
			destif="eth2"
			echo -e "\tpost-up route add -net ${destnetwork} netmask ${destmask} gw ${destgw} dev ${destif}" >> ${nodeiffile}
			echo -e "\tpre-down route add -net ${destnetwork} netmask ${destmask} gw ${destgw} dev ${destif}" >> ${nodeiffile}
		    done

		fi
	fi

	# Increment subnet if necessary
	if [ "${nodetype}" = "router" ]; then
	    subnet=$(( ${subnet} + 1 ));
	fi
done

if [ "${specialcase}" = "ring" ]; then
	echo "TODO: create ring by connecting router1 to routerN"
fi

if [ "${drawdot}" = "1" ]; then
	echo "}" | tee -a ${dotfilenamed} ${dotfilenodes} > /dev/null
fi