#!/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.in,v 1.21 2003/10/02 07:30:23 sam 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
# %unchanged or setting (0, 1, or 2)
rpfiltercontrol=0
ipsecversion=/proc/net/ipsec_version
moduleplace=/lib/modules/`uname -r`/kernel/net/ipsec
bareversion=`uname -r | sed -e 's/^\(2\.[0-9]\.[1-9][0-9]*-[1-9][0-9]*\(\.[0-9][0-9]*\)*\(\.x\)*\).*$/\1/'`
moduleinstplace=/lib/modules/$bareversion/kernel/net/ipsec
modulename=ipsec.o
klips=true
kamepfkey=/proc/net/pfkey

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	;;
	--rpfilter)	rpfiltercontrol="$2" ; shift	;;
	--)	shift ; break	;;
	-*)	echo "$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

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

	# 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() {
	$klips || return 0
	rpf=$rpfilter1/$1/$rpfilter2
	if test -f $rpf
	then
		r="`cat $rpf`"
		if test " $r" != " 0"
		then
			case "$r-$rpfiltercontrol" in
			0-%unchanged|0-0|1-1|2-2)
				# happy state
				;;
			*-%unchanged)
				echo "WARNING: $1 has route filtering turned on; KLIPS may not work ($rpf is $r)"
				;;
			[012]-[012])
				echo "WARNING: changing route filtering on $1 (changing $rpf from $r to $rpfiltercontrol)"
				echo "$rpfiltercontrol" >$rpf
				;;
			[012]-*)
				echo "ERROR: unknown rpfilter setting: $rpfiltercontrol"
				;;
			*)
				echo "ERROR: unknown $rpf value $r"
				;;
			esac
		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() {
        wantgoo="`ipsec calcgoo /proc/ksyms`"
        module=$moduleplace/$modulename
        if test -f $module
        then
                goo="`nm -ao $module | ipsec calcgoo`"
                if test " $wantgoo" = " $goo"
                then
                        return          # looks right
                fi
        fi
        if test -f $moduleinstplace/$wantgoo
        then
                echo "insmod failed, but found matching template module $wantgoo."
                echo "Copying $moduleinstplace/$wantgoo to $module."
                rm -f $module
                mkdir -p $moduleplace
                cp -p $moduleinstplace/$wantgoo $module
                # "depmod -a" gets done by caller
        fi
}



# main line

# load module if possible
if test ! -f $ipsecversion && test ! -f $kamepfkey
then
    # statically compiled KLIPS not found; try to load the module
    insmod ipsec
fi

if test ! -f $ipsecversion && test ! -f $kamepfkey
then
	modprobe -v af_key
fi

if test -f $kamepfkey
then
	klips=false
	modprobe -qv ah4
	modprobe -qv esp4
	modprobe -qv ipcomp
	modprobe -qv xfrm_user
fi

if test ! -f $ipsecversion && $klips
then
        if test -r $modules             # kernel does have modules
        then
                setmodule
                unset MODPATH MODULECONF        # no user overrides!
                depmod -a >/dev/null 2>&1
                modprobe -v 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
elif $klips
then
	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
elif $klips
then
	echo "WARNING: cannot adjust KLIPS flags, no $sysflags directory!"
	# carry on
fi

if $klips; then
	# clear tables out in case dregs have been left over
	ipsec eroute --clear
	ipsec spi --clear
else
	if type setkey > /dev/null 2>&1; then
		setkey -F
		setkey -FP
	else
		echo "WARNING: setkey not found."
	fi
fi

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

exit 0