#!/bin/sh
# KLIPS startup script
# Copyright (C) 1998, 1999, 2001, 2002  Henry Spencer.
# 
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
# 
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
# for more details.
#
# RCSID $Id: _startklips,v 1.6.2.1 2002/04/09 21:34:56 mcr Exp $

me='ipsec _startklips'		# for messages

# KLIPS-related paths
sysflags=/proc/sys/net/ipsec
modules=/proc/modules
# full rp_filter path is $rpfilter1/interface/$rpfilter2
rpfilter1=/proc/sys/net/ipv4/conf
rpfilter2=rp_filter
ipsecversion=/proc/net/ipsec_version
modulesdir=/lib/modules/ipsec
moduleplace=/lib/modules/`uname -r`/kernel/net/ipsec
modulename=ipsec.o

info=/dev/null
log=daemon.error
for dummy
do
	case "$1" in
	--log)		log="$2" ; shift	;;
	--info)		info="$2" ; shift	;;
	--debug)	debug="$2" ; shift	;;
	--omtu)		omtu="$2" ; shift	;;
	--fragicmp)	fragicmp="$2" ; shift	;;
	--hidetos)	hidetos="$2" ; shift	;;
	--default)	packetdefault="$2" ; shift	;;
	--)	shift ; break	;;
	-*)	echo "$me: unknown option \`$1'" >&2 ; exit 2	;;
	*)	break	;;
	esac
	shift
done



# some shell functions, to clarify the actual code

# set up a system flag based on a variable
# sysflag value shortname default flagname
sysflag() {
	case "$1" in
	'')	v="$3"	;;
	*)	v="$1"	;;
	esac
	if test ! -f $sysflags/$4
	then
		if test " $v" != " $3"
		then
			echo "cannot do $2=$v, $sysflags/$4 does not exist"
			exit 1
		else
			return	# can't set, but it's the default anyway
		fi
	fi
	case "$v" in
	yes|no)	;;
	*)	echo "unknown (not yes/no) $2 value \`$1'"
		exit 1
		;;
	esac
	case "$v" in
	yes)	echo 1 >$sysflags/$4	;;
	no)	echo 0 >$sysflags/$4	;;
	esac
}

# set up a Klips interface
klipsinterface() {
	# pull apart the interface spec
	virt=`expr $1 : '\([^=]*\)=.*'`
	phys=`expr $1 : '[^=]*=\(.*\)'`
	case "$virt" in
	ipsec[0-9])	;;
	*)	echo "invalid interface \`$virt' in \`$1'" ; exit 1	;;
	esac

	# figure out ifconfig for interface
	addr=
	eval `ifconfig $phys |
		awk '$1 == "inet" && $2 ~ /^addr:/ && $NF ~ /^Mask:/ {
			gsub(/:/, " ", $0)
			print "addr=" $3
			other = $5
			if ($4 == "Bcast")
				print "type=broadcast"
			else if ($4 == "P-t-P")
				print "type=pointopoint"
			else if (NF == 5) {
				print "type="
				other = ""
			} else
				print "type=unknown"
			print "otheraddr=" other
			print "mask=" $NF
		}'`
	if test " $addr" = " "
	then
		echo "unable to determine address of \`$phys'"
		exit 1
	fi
	if test " $type" = " unknown"
	then
		echo "\`$phys' is of an unknown type"
		exit 1
	fi
	if test " $omtu" != " "
	then
		mtu="mtu $omtu"
	else
		mtu=
	fi
	echo "KLIPS $virt on $phys $addr/$mask $type $otheraddr $mtu" | logonly

	# attach the interface and bring it up
	ipsec tncfg --attach --virtual $virt --physical $phys
	ifconfig $virt inet $addr $type $otheraddr netmask $mask $mtu

	# if %defaultroute, note the facts
	if test " $2" != " "
	then
		(
			echo "defaultroutephys=$phys"
			echo "defaultroutevirt=$virt"
			echo "defaultrouteaddr=$addr"
			if test " $2" != " 0.0.0.0"
			then
				echo "defaultroutenexthop=$2"
			fi
		) >>$info
	else
		echo '#dr: no default route' >>$info
	fi

	# check for rp_filter trouble
	checkif $phys			# thought to be a problem only on phys
}

# check an interface for problems
checkif() {
	rpf=$rpfilter1/$1/$rpfilter2
	if test -f $rpf
	then
		r="`cat $rpf`"
		if test " $r" != " 0"
		then
			echo "WARNING: $1 has route filtering turned on, KLIPS may not work"
			echo " ($rpf = \`$r', should be 0)"
		fi
	fi
}

# interfaces=%defaultroute:  put ipsec0 on top of default route's interface
defaultinterface() {
	phys=`netstat -nr |
		awk '$1 == "0.0.0.0" && $3 == "0.0.0.0" { print $NF }'`
	if test " $phys" = " "
	then
		echo "no default route, %defaultroute cannot cope!!!"
		exit 1
	fi
	if test `echo " $phys" | wc -l` -gt 1
	then
		echo "multiple default routes, %defaultroute cannot cope!!!"
		exit 1
	fi
	next=`netstat -nr |
		awk '$1 == "0.0.0.0" && $3 == "0.0.0.0" { print $2 }'`
	klipsinterface "ipsec0=$phys" $next
}

# log only to syslog, not to stdout/stderr
logonly() {
	logger -p $log -t ipsec_setup
}

# sort out which module is appropriate, changing it if necessary
setmodule() {
	if test ! -d $modulesdir
	then
		return			# nothing we can do anyway
	fi
	wantgoo="`sed -n '/ netif_rx_R/s/.*_R//p' /proc/ksyms`"
	module=$moduleplace/$modulename
	if test -f $module
	then
		goo="`nm -ug $module | sed -n '/ netif_rx_R/s/.*_//p'`"
		if test " $wantgoo" = " $goo"
		then
			return		# looks right
		fi
	fi
	if test -f $modulesdir/$wantgoo
	then
		echo "KLIPS module needed changing (to $wantgoo)" | logonly
		rm -f $module
		mkdir -p $moduleplace
		cp -p $modulesdir/$wantgoo $module
		# "depmod -a" gets done by caller
	fi
}



# main line

# load module if necessary
if test ! -f $ipsecversion
then
	if test -r $modules		# kernel does have modules
	then
		setmodule
		unset MODPATH MODULECONF	# no user overrides!
		depmod -a >/dev/null 2>&1 && modprobe ipsec
	fi
	if test ! -f $ipsecversion
	then
		echo "kernel appears to lack KLIPS"
		exit 1
	fi
fi

# figure out debugging flags
case "$debug" in
'')	debug=none	;;
esac
if test -r /proc/net/ipsec_klipsdebug
then
	echo "KLIPS debug \`$debug'" | logonly
	case "$debug" in
	none)	ipsec klipsdebug --none	;;
	all)	ipsec klipsdebug --all	;;
	*)	ipsec klipsdebug --none
		for d in $debug
		do
			ipsec klipsdebug --set $d
		done
		;;
	esac
else
	if test " $debug" != " none"
	then
		echo "klipsdebug=\`$debug' ignored, KLIPS lacks debug facilities"
	fi
fi

# figure out misc. kernel config
if test -d $sysflags
then
	sysflag "$fragicmp" "fragicmp" yes icmp
	echo 1 >$sysflags/inbound_policy_check		# no debate
	sysflag no "no_eroute_pass" no no_eroute_pass	# obsolete parm
	sysflag no "opportunistic" no opportunistic	# obsolete parm
	sysflag "$hidetos" "hidetos" yes tos
else
	echo "WARNING: cannot adjust KLIPS flags, no $sysflags directory!"
	# carry on
fi

# clear tables out in case dregs have been left over
ipsec eroute --clear
ipsec spi --clear

# figure out interfaces
for i
do
	case "$i" in
	ipsec*=?*)	klipsinterface "$i"	;;
	%defaultroute)	defaultinterface	;;
	*)	echo "interface \`$i' not understood"
		exit 1
		;;
	esac
done

# set up default eroute if necessary
case "$packetdefault" in
pass|reject)
	ipsec eroute --label "packetdefault" --replace --eraf inet \
		--src 0/0 --dst 0/0 --said "%$packetdefault"
	;;
drop)	;;		# default
*)	echo "unknown packetdefault value \`$packetdefault'"
	exit 1
	;;
esac

exit 0