#!/bin/sh
#
#     Shorewall Packet Filtering Firewall Capabilities Detector
#
#     This program is under GPL [http://www.gnu.org/copyleft/gpl.htm]
#
#     (c) 2006 - Tom Eastep (teastep@shorewall.net)
#
#	This file should be placed in /sbin/shorewall.
#
#	Shorewall documentation is available at http://shorewall.sourceforge.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
#
#
#   This program may be used to create a /etc/shorewall/capabilities file for
#   use in compiling Shorewall firewalls on another system.
#
#   On the target system (the system where the firewall program is to run):
#
#       [ IPTABLES=<iptables binary> ] [ MODULESDIR=<kernel modules directory> ] shorecap > capabilities
#
#    Now move the capabilities file to the compilation system. The file must
#    be placed in a directory on the CONFIG_PATH to be used when compiling firewalls
#    for the target system.
#
#    Default values for the two variables are:
#
#        IPTABLES - iptables
#        MODULESDIR - /lib/modules/$(uname -r)/kernel/net/ipv4/netfilter
#
#    Shorewall need not be installed on the target system to run shorecap. If the '-e' flag is
#    used during firewall compilation, then the generated firewall program will likewise not
#    require Shorewall to be installed.

VERSION=3.1.6

#
# Suppress all output for a command
#
qt()
{
    "$@" >/dev/null 2>&1
}

#
# Split a colon-separated list into a space-separated list
#
split() {
    local ifs=$IFS
    IFS=:
    set -- $1
    echo $*
    IFS=$ifs
}

#
# Internal version of 'which'
#
mywhich() {
    local dir

    for dir in $(split $PATH); do
	if [ -x $dir/$1 ]; then
	    echo $dir/$1
	    return 0
	fi
    done

    return 2
}

#
# Load a Kernel Module
#
loadmodule() # $1 = module name, $2 - * arguments
{
    local modulename=$1
    local modulefile
    local suffix
    moduleloader=modprobe

    if ! qt mywhich modprobe; then
	moduleloader=insmod
    fi

    if [ -z "$(lsmod | grep $modulename)" ]; then
	shift

	for suffix in $MODULE_SUFFIX ; do
	    modulefile=$MODULESDIR/${modulename}.${suffix}

	    if [ -f $modulefile ]; then
		case $moduleloader in
		    insmod)
			insmod $modulefile $*
			;;
		    *)
			modprobe $modulename $*
			;;
		esac

		return
	    fi
	done
    fi
}

#
# Load kernel modules required for Shorewall
#
load_kernel_modules()
{
    [ -z "$MODULESDIR" ] && \
	MODULESDIR=/lib/modules/$(uname -r)/kernel/net/ipv4/netfilter

    #
    # Essential Modules
    #
    loadmodule ip_tables
    loadmodule iptable_filter
    loadmodule ip_conntrack
    #
    # Helpers
    #
    loadmodule ip_conntrack_ftp
    loadmodule ip_conntrack_tftp
    loadmodule ip_conntrack_irc
    loadmodule iptable_nat
    loadmodule ip_nat_ftp
    loadmodule ip_nat_tftp
    loadmodule ip_nat_irc
    loadmodule ip_set
    loadmodule ip_set_iphash
    loadmodule ip_set_ipmap
    loadmodule ip_set_macipmap
    loadmodule ip_set_portmap
    #
    # Traffic Shaping
    #
    loadmodule sch_sfq
    loadmodule sch_ingress
    loadmodule sch_htb
    loadmodule cls_u32
    #
    # Extensions
    #
    loadmodule ipt_addrtype
    loadmodule ipt_ah
    loadmodule ipt_CLASSIFY
    loadmodule ipt_CLUSTERIP
    loadmodule ipt_comment
    loadmodule ipt_connmark
    loadmodule ipt_CONNMARK
    loadmodule ipt_conntrack
    loadmodule ipt_dscp
    loadmodule ipt_DSCP
    loadmodule ipt_ecn
    loadmodule ipt_ECN
    loadmodule ipt_esp
    loadmodule ipt_hashlimit
    loadmodule ipt_helper
    loadmodule ipt_ipp2p
    loadmodule ipt_iprange
    loadmodule ipt_length
    loadmodule ipt_limit
    loadmodule ipt_LOG
    loadmodule ipt_mac
    loadmodule ipt_mark
    loadmodule ipt_MARK
    loadmodule ipt_MASQUERADE
    loadmodule ipt_multiport
    loadmodule ipt_NETMAP
    loadmodule ipt_NOTRACK
    loadmodule ipt_owner
    loadmodule ipt_physdev
    loadmodule ipt_pkttype
    loadmodule ipt_policy
    loadmodule ipt_realm
    loadmodule ipt_recent
    loadmodule ipt_REDIRECT
    loadmodule ipt_REJECT
    loadmodule ipt_SAME
    loadmodule ipt_sctp
    loadmodule ipt_set
    loadmodule ipt_state
    loadmodule ipt_tcpmss
    loadmodule ipt_TCPMSS
    loadmodule ipt_tos
    loadmodule ipt_TOS
    loadmodule ipt_ttl
    loadmodule ipt_TTL
    loadmodule ipt_ULOG

}

#
# Determine which optional facilities are supported by iptables/netfilter
#
determine_capabilities() {
    [ -z "$IPTABLES" ] && IPTABLES=$(mywhich iptables)

    [ -z "$IPTABLES" ] && { echo "ERROR: Can't find IPTABLES executable" ; exit 2; }

    qt $IPTABLES -t nat    -L -n && NAT_ENABLED=Yes    || NAT_ENABLED=
    qt $IPTABLES -t mangle -L -n && MANGLE_ENABLED=Yes || MANGLE_ENABLED=

    CONNTRACK_MATCH=
    MULTIPORT=
    XMULTIPORT=
    POLICY_MATCH=
    PHYSDEV_MATCH=
    IPRANGE_MATCH=
    RECENT_MATCH=
    OWNER_MATCH=
    IPSET_MATCH=
    CONNMARK=
    CONNMARK_MATCH=
    RAW_TABLE=
    IPP2P_MATCH=
    LENGTH_MATCH=
    CLASSIFY_TARGET=
    ENHANCED_REJECT=
    USEPKTTYPE=

    qt $IPTABLES -N fooX1234
    qt $IPTABLES -A fooX1234 -m conntrack --ctorigdst 192.168.1.1 -j ACCEPT             && CONNTRACK_MATCH=Yes
    qt $IPTABLES -A fooX1234 -p tcp -m multiport --dports 21,22 -j ACCEPT               && MULTIPORT=Yes
    qt $IPTABLES -A fooX1234 -p tcp -m multiport --dports 21:22 -j ACCEPT               && XMULTIPORT=Yes
    qt $IPTABLES -A fooX1234 -m policy --pol ipsec --mode tunnel --dir in -j ACCEPT     && POLICY_MATCH=Yes
    qt $IPTABLES -A fooX1234 -m physdev --physdev-in eth0 -j ACCEPT                     && PHYSDEV_MATCH=Yes
    qt $IPTABLES -A fooX1234 -m iprange --src-range 192.168.1.5-192.168.1.124 -j ACCEPT && IPRANGE_MATCH=Yes
    qt $IPTABLES -A fooX1234 -m recent --update -j ACCEPT                               && RECENT_MATCH=Yes
    qt $IPTABLES -A fooX1234 -m owner --uid-owner 0 -j ACCEPT                           && OWNER_MATCH=Yes
    qt $IPTABLES -A fooX1234 -m connmark --mark 2  -j ACCEPT                            && CONNMARK_MATCH=Yes
    qt $IPTABLES -A fooX1234 -p tcp -m ipp2p --ipp2p -j ACCEPT                          && IPP2P_MATCH=Yes
    qt $IPTABLES -A fooX1234 -m length --length 10:20 -j ACCEPT                         && LENGTH_MATCH=Yes
    qt $IPTABLES -A fooX1234 -j REJECT --reject-with icmp-host-prohibited               && ENHANCED_REJECT=Yes

    qt $IPTABLES -t mangle -N fooX1234
    qt $IPTABLES -t mangle -A fooX1234 -j CONNMARK --save-mark                          && CONNMARK=Yes
    qt $IPTABLES -t mangle -A fooX1234 -j CLASSIFY --set-class 1:1                      && CLASSIFY_TARGET=Yes
    qt $IPTABLES -t mangle -F fooX1234
    qt $IPTABLES -t mangle -X fooX1234

    qt $IPTABLES -t raw	   -L -n							&& RAW_TABLE=Yes

    if qt mywhich ipset; then
	qt ipset -X fooX1234 # Just in case something went wrong the last time

	if qt ipset -N fooX1234 iphash ; then
	    if qt $IPTABLES -A fooX1234 -m set --set fooX1234 src -j ACCEPT; then
		qt $IPTABLES -D fooX1234 -m set --set fooX1234 src -j ACCEPT
		IPSET_MATCH=Yes
	    fi
	    qt ipset -X fooX1234
	fi
    fi

    qt $IPTABLES -A fooX1234 -m pkttype --pkt-type broadcast -j ACCEPT && USEPKTTYPE=Yes

    qt $IPTABLES -F fooX1234
    qt $IPTABLES -X fooX1234
}

report_capability() # $1 = Capability
{
    local setting

    eval setting=\$$1

    echo $1=$setting

}

report_capabilities() {
    echo "#"
    echo "#Shorewall $VERSION detected the following iptables/netfilter capabilities - $(date)"
    echo "#"
    report_capability NAT_ENABLED
    report_capability MANGLE_ENABLED
    report_capability MULTIPORT
    [ -n "$MULTIPORT" ] && report_capability XMULTIPORT
    report_capability CONNTRACK_MATCH
    report_capability USEPKTTYPE
    report_capability POLICY_MATCH
    report_capability PHYSDEV_MATCH
    report_capability LENGTH_MATCH
    report_capability IPRANGE_MATCH
    report_capability RECENT_MATCH
    report_capability OWNER_MATCH
    report_capability IPSET_MATCH
    report_capability CONNMARK
    report_capability CONNMARK_MATCH
    report_capability RAW_TABLE
    report_capability IPP2P_MATCH
    report_capability CLASSIFY_TARGET
    report_capability ENHANCED_REJECT
}

load_kernel_modules
determine_capabilities
report_capabilities