#!/bin/sh

CONFFILE=/usr/local/etc/wssh.conf
MINPORT=1025
MAXPORT=65535
DEFPORT=2200

# function which will use egrep to see if the first
# argument patches the second argument.
# NOTE: ONLY the second argument maybe an extended regular expression
match()
{
	string="$1"
	regexp="$2"
	echo "$string" | egrep -w "$regexp" >/dev/null
	return $?
}

chooseRandomPort()
{
	PORTFORWARD=0
	while [ $PORTFORWARD -lt $MINPORT -o $PORTFORWARD -gt $MAXPORT ]
	do
	if [ -x /bin/ksh ]
	then
		PORTFORWARD=`/bin/ksh -c 'echo $RANDOM'`
	else
		if [ -x /bin/bash ]
		then
			PORTFORWARD=`/bin/bash -c 'echo $RANDOM'`
		else
			PORTFORWARD=$DEFPORT
		fi
	fi
	done
}

# If you use a passphrase with your keys, and you will be going
# through more than one hop, you MUST uncomment this option
AGENTFW="-A"
NOCHECK="-oStrictHostKeyChecking=no -oNoHostAuthenticationForLocalhost=yes"
QUIET="-q"
EXTRA="$AGENTFW $NOCHECK $QUIET"

# looks in the conf file and returns a list of the hops to make
getproxy()
{
	cat $CONFFILE |grep -v "^#" | tr '[A-Z]' '[a-z]' |
	while read regexp proxy
	do
		#echo "trying $regexp" >&2
		if match "$dest" "$regexp"
		then
			echo $proxy
			return 0 
		fi
	done
	echo ""
	return 1 
}


# sets up a tunnel similar to this
#ssh dogmatix -t -L 2200:localhost:2200 ssh falbala -N -t -L 2200:justforkix:22
setuptunnel()
{
	dest=$1
	proxy=`getproxy $dest`

	#echo proxy is $proxy

	# if no proxy assume can get there directly
	if [ -z "$proxy" ]
	then
		return 1
	else
		#for each proxy in the list, construct the command
		# each intermediate must go to background or it won't finish
		set $proxy
		while [ $# -gt 1 ]
		do
			cmdline="$cmdline ssh $1 $EXTRA -f -L $PORTFORWARD:localhost:$PORTFORWARD"
			shift
		done

		# last proxy
		# this is a total hack, but it works.
		# it seems that if we use -N, then the damn intermediate
		# tunnel never dies, BUT, if we put a sleep at the
		# end, then the sleep will end, but the tunnel won't
		# terminate until the connection running over it
		# terminates... Kind of cool actually
		cmdline="$cmdline ssh $1 $EXTRA -f -L $PORTFORWARD:$dest:22 sleep 5"
		# execute the command
		$cmdline
		ret=$?
		# sleep for a bit to give the connection time to setup
		sleep 2
	fi
	return $ret
}

teardowntunnel()
{
	SSHPFPID=`ps -ef |
		egrep "ssh.*-L $PORTFORWARD" |
		awk '{print $2}'`
	kill $SSHPFPID 2>/dev/null
}

##### main

# This program acts differently depending on its name
# it can be called as wssh or wscp

chooseRandomPort

case `basename $0` in
wssh)
	if [ -z "$1" ]
	then
		echo "USAGE: $0 hostname" >&2
		exit 1
	fi
	dest=$1
	shift
	setuptunnel $dest
	ret=$?
	case $ret in
	0)
		#tunnel is set 
		ssh $NOCHECK -p $PORTFORWARD localhost $*
		ret=$?
		;;
	1)
		#no tunnel required
		ssh $NOCHECK $dest $*
		ret=$?
		;;
	*)
		#something failed
		echo "ERROR setting up tunnel"
		;;
	esac
	#teardowntunnel
	;;
wscp)
	if [ -z "$1" ]
	then
		echo "USAGE: $0 localfile host:file" >&2
		exit 1
	fi

	localfile=$1
	dest=`echo $2 | sed -e "s/:.*//"`
	destfile=`echo $2 | sed -e "s/.*://"`
	setuptunnel $dest
	ret=$?
	case $ret in
	0)
		scp $NOCHECK $QUIET -P $PORTFORWARD \
			$localfile localhost:$destfile
		ret=$?
		;;
	1)
		#no tunnel required
		scp $NOCHECK $QUIET $localfile $dest:$destfile
		ret=$?
		;;
	*)
		#something failed
		echo "ERROR setting up tunnel"
		;;
	esac
esac

exit $ret