#!/bin/sh

################################################################################
#
#    ipsecvpn -- script for use on a roadwarrior to start/stop a tunnel-mode
#                IPSEC connection
#
#     This program is under GPL [http://www.gnu.org/copyleft/gpl.htm]
#
#     (c) 2004 - Tom Eastep (teastep@shorewall.net)
#
#	This program is free software; you can redistribute it and/or modify
#	it under the terms of Version 2 of the GNU General Public License
#	as published by the Free Software Foundation.
#
#	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.
#
#	You should have received a copy of the GNU General Public License
#	along with this program; if not, write to the Free Software
#	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA

RCDLINKS="2,S42 3,S42 6,K42"

#### BEGIN INIT INFO
# Provides:	  ipsecvpn
# Required-Start: $shorewall
# Required-Stop:
# Default-Start:  2 3 5
# Default-Stop:	  0 1 6
# Description:	  starts and stops a tunnel-mode VPN connection
### END INIT INFO

# chkconfig: 2345 26 89
# description: IPSEC tunnel-mode connection
#
################################################################################
#
# External Interface
#
INTERFACE=eth0
#
# Remote IPSEC Gateway
#
GATEWAY=1.2.3.4
#
# Networks behind the remote gateway (space-separated list)
#
NETWORKS="192.168.1.0/24"
#
# Directory where X.509 certificates are stored.
#
CERTS=/etc/certs
#
# Certificate to be used for this connection. The cert 
# directory must contain:
#
#     ${CERT}.pem     - the certificate
#     ${CERT}_key.pem - the certificates's key
#
CERT=roadwarrior
#
#     The setkey binary
#
SETKEY=/usr/sbin/setkey
#
#     The racoon binary
#
RACOON=/usr/sbin/racoon

#
# Message to stderr
#
error_message() # $* = Error Message
{
   echo "   $@" >&2
}

#
# Fatal error -- stops the firewall after issuing the error message
#
fatal_error() # $* = Error Message
{
    echo "   Error: $@" >&2
    exit 2
}

#
# Find interface address--returns the first IP address assigned to the passed
# device
#
find_first_interface_address() # $1 = interface
{
    #
    # get the line of output containing the first IP address
    #
    addr=$(ip -f inet addr show $1 2> /dev/null | grep inet | head -n1)
    #
    # If there wasn't one, bail out now
    #
    [ -n "$addr" ] || fatal_error "Can't determine the IP address of $1"
    #
    # Strip off the trailing VLSM mask (or the peer IP in case of a P-t-P link)
    # along with everything else on the line
    #
    echo $addr | sed 's/inet //;s/\/.*//;s/ peer.*//'
}

#
# Create a Racoon configuration file using the variables above
#
make_racoon_conf() {
    echo "path certificate \"$CERTS\";"
    echo
    echo "listen"
    echo "{"
    echo "    isakmp $IPADDR;"
    echo "}"
    echo
    echo "remote $GATEWAY"
    echo "{"
    echo "    exchange_mode main;"
    echo "    certificate_type x509 \"$CERT.pem\" \"${CERT}_key.pem\";"
    echo "    verify_cert on;"
    echo "    my_identifier asn1dn ;"
    echo "    peers_identifier asn1dn ;"
    echo "    verify_identifier on ;"
    echo "    lifetime time 24 hour ;"
    echo "    proposal {"
    echo "        encryption_algorithm blowfish;"
    echo "        hash_algorithm sha1;"
    echo "        authentication_method rsasig ;"
    echo "        dh_group 2 ;"
    echo "    }"
    echo "}"
    echo

    for network in $NETWORKS; do
	echo "sainfo address $IPADDR/32 any address $network any"
	echo "{"
	echo "    pfs_group 2;"
	echo "    lifetime time 12 hour ;"
	echo "    encryption_algorithm blowfish ;"
	echo "    authentication_algorithm hmac_sha1, hmac_md5 ;"
	echo "    compression_algorithm deflate ;"
	echo "}"
	echo
	echo "sainfo address $network any address $IPADDR/32 any"
	echo "{"
	echo "    pfs_group 2;"
	echo "    lifetime time 12 hour ;"
	echo "    encryption_algorithm blowfish ;"
	echo "    authentication_algorithm hmac_sha1, hmac_md5 ;"
	echo "    compression_algorithm deflate ;"
	echo "}"

    done

    echo "sainfo address $IPADDR/32 any address $GATEWAY/32 any"
    echo "{"
    echo "    pfs_group 2;"
    echo "    lifetime time 12 hour ;"
    echo "    encryption_algorithm blowfish ;"
    echo "    authentication_algorithm hmac_sha1, hmac_md5 ;"
    echo "    compression_algorithm deflate ;"
    echo "}"
    echo
    echo "sainfo address $GATEWAY/32 any address $IPADDR/32 any"
    echo "{"
    echo "    pfs_group 2;"
    echo "    lifetime time 12 hour ;"
    echo "    encryption_algorithm blowfish ;"
    echo "    authentication_algorithm hmac_sha1, hmac_md5 ;"
    echo "    compression_algorithm deflate ;"
    echo "}"
}

#
# Make a setkey configuration file using the variables above
#
make_setkey_conf() 
{
    echo "flush;"
    echo "spdflush;"

    echo "spdadd $IPADDR/32 $GATEWAY/32 any -P out  ipsec esp/tunnel/${IPADDR}-${GATEWAY}/require;"
    echo "spdadd $GATEWAY/32 $IPADDR/32 any -P in   ipsec esp/tunnel/${GATEWAY}-${IPADDR}/require;"
    
    for network in $NETWORKS; do
	echo "spdadd $IPADDR/32 $network any -P out  ipsec esp/tunnel/${IPADDR}-${GATEWAY}/require;"
	echo "spdadd $network $IPADDR/32 any -P in   ipsec esp/tunnel/${GATEWAY}-${IPADDR}/require;"
    done
}

#
# Start the Tunnel
#
start() 
{
    #
    # Get the first IP address configured on the device in INTERFACE
    #
    IPADDR=$(find_first_interface_address $INTERFACE)
    #
    # Create the name of the setkey temporary file
    #
    TEMPFILE=$(mktemp /tmp/$(basename $0).XXXXXXXX)
    [ $? -eq 0 ] || fatal_error "Can't create temporary file name"
    #
    # Create the file
    #
    make_setkey_conf > $TEMPFILE
    #
    # Create the SPD
    #
    $SETKEY -f $TEMPFILE
    #
    # We can now remove the file
    #
    rm -f $TEMPFILE
    #
    # Create another name -- make this distict to aid debugging
    # (just comment out the 'rm' commands)
    #
    TEMPFILE=$(mktemp /tmp/$(basename $0).XXXXXXXX)
    [ $? -eq 0 ] || fatal_error "Can't create temporary file name"
    #
    # Create the file
    #
    make_racoon_conf > $TEMPFILE
    #
    # Start Racoon Daemon
    #
    $RACOON -4 -f $TEMPFILE
    #
    # Once the Daemon is running, we can remove the file
    #
    rm -f $TEMPFILE
}
#
# Stop the Tunnel
#
stop() 
{
    #
    # Kill any racoon daemons
    #
    killall racoon
    #
    # Purge the SAD and SPD
    #
    setkey -F -FP
}

#
# Display command syntax and abend
#
usage() 
{
    error_message "usage: $(basename $0) [start|stop|restart]"
    exit 1
}
################################################################################
#                       C O D E    S T A R T S    H E R E
################################################################################
[ $# -eq 1 ] || usage


case $1 in
    start)
	start
	;;
    stop)
	stop
	;;
    restart)
	stop
	sleep 2
	start
	;;
    *)
	usage
	;;
esac