#! /usr/bin/perl -w
#
#     The Shoreline Firewall4 (Shorewall-perl) Packet Filtering Firewall Compiler - V3.9
#
#     This program is under GPL [http://www.gnu.org/copyleft/gpl.htm]
#
#     (c) 2007 - Tom Eastep (teastep@shorewall.net)
#
#	Complete documentation is available at http://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
#
#	Commands are:
#
#          compiler.pl                          Verify the configuration files.
#	   compile <path name>                  Compile into <path name>
#
#	Environmental Variables are set up by the Compiler wrapper ('compiler' program).
#
#	    EXPORT=Yes                          -e option specified to /sbin/shorewall
#	    SHOREWALL_DIR                       A directory name was passed to /sbin/shorewall
#	    VERBOSE                             Standard Shorewall verbosity control.
#           VERSION                             Shorewall Version
#           TMP_DIR                             Temporary Directory containing stripped copies
#                                               of all configuration files. Shell variable substitution 
#                                               has been performed on these files.
#           TIMESTAMP=Yes                       -t option specified to /sbin/shorewall
#
#       This program performs rudimentary shell variable expansion on action and macro files.

use strict;
use lib '/usr/share/shorewall-perl';
use Shorewall::Common;
use Shorewall::Config;
use Shorewall::Chains;
use Shorewall::Zones;
use Shorewall::Interfaces;
use Shorewall::Hosts;
use Shorewall::Policy;
use Shorewall::Nat;
use Shorewall::Providers;
use Shorewall::Tc;
use Shorewall::Tunnels;
use Shorewall::Macros;
use Shorewall::Actions;
use Shorewall::Accounting;
use Shorewall::Rules;
use Shorewall::Proc;
use Shorewall::Proxyarp;

#
# Note to the reader.
#
#     I use Emacs perl-mode. It's advantages are:
#
#         It's color theme is visible to color-blind people like me.
#         It's indentation scheme is exactly the way I like.
#
#      But:
#
#         It doesn't understand 'here documents'.
#
#     I've tried cperl-mode. It's adavantages are:
#         
#         It understands 'here documents'.
#
#     But:
#
#         It's color theme drives my eyes crazy.
#         It's indentation scheme is unfathomable.
#
#     Bottom line. I use quoting techinques other than 'here documents'.
#

#
# First stage of script generation.
#
#    Copy the prog.header to the generated script.
#    Generate the various user-exit jacket functions.
#    Generate the 'initialize()' function.
#

sub generate_script_1 {
    copy $env{SHAREDIRPL} . 'prog.header';

    my $date = localtime;

    emit "#\n# Compiled firewall script generated by Shorewall-perl $env{VERSION} - $date\n#";

    if ( $ENV{EXPORT} ) {
	emitj ( 'SHAREDIR=/usr/share/shorewall-lite',
		'CONFDIR=/etc/shorewall-lite',
		'VARDIR=/var/lib/shorewall-lite',
		'PRODUCT="Shorewall Lite"'
		);

	copy "$env{SHAREDIR}/lib.base";

	emitj ( '################################################################################',
		'# End of /usr/share/shorewall/lib.base',
		'################################################################################'
		);
    } else {
	emitj ( 'SHAREDIR=/usr/share/shorewall',
		'CONFDIR=/etc/shorewall',
		'VARDIR=/var/lib/shorewall',
		'PRODUCT=\'Shorewall\'',
		'. /usr/share/shorewall/lib.base'
		);
    }

    emit "TEMPFILE=\n";
    
    for my $exit qw/init start tcclear started stop stopped/ {
	emit "run_${exit}_exit() {";
	push_indent;
	append_file $exit;
	emit 'true';
	pop_indent;
	emit "}\n";
    }

    emitj ( 'initialize()', 
	    '{' 
	    );

    push_indent;

    if ( $ENV{EXPORT} ) {
	emitj ( '#',
		'# These variables are required by the library functions called in this script',
		'#',
		'CONFIG_PATH="/etc/shorewall-lite:/usr/share/shorewall-lite"' );
    } else {
	emitj ( 'if [ ! -f ${SHAREDIR}/version ]; then',
		'    fatal_error "This script requires Shorewall which do not appear to be installed on this system (did you forget \"-e\" when you compiled?)"',
		'fi',
		'',
		'local version=$(cat ${SHAREDIR}/version)',
		'',
		'if [ ${SHOREWALL_LIBVERSION:-0} -lt 30401 ]; then',
		'    fatal_error "This script requires Shorewall version 3.4.2 or later; current version is $version"',
		'fi',
		'#',
		'# These variables are required by the library functions called in this script',
		'#',
		qq(CONFIG_PATH="$config{CONFIG_PATH}") );
    }

    propagateconfig;

    emitj ( '[ -n "${COMMAND:=restart}" ]',
	    '[ -n "${VERBOSE:=0}" ]',
	    qq([ -n "\${RESTOREFILE:=$config{RESTOREFILE}}" ]),
	    '[ -n "$LOGFORMAT" ] || LOGFORMAT="Shorewall:%s:%s:"',
	    qq(VERSION="$env{VERSION}") ,
	    qq(PATH="$config{PATH}") ,
	    'TERMINATOR=fatal_error'
	    );

    if ( $config{IPTABLES} ) {
	emitj( qq(IPTABLES="$config{IPTABLES}"),
	       '',
	       '[ -x "$IPTABLES" ] || startup_error "IPTABLES=$IPTABLES does not exist or is not executable"',
	       );
    } else {
	emitj( '[ -z "$IPTABLES" ] && IPTABLES=$(mywhich iptables 2> /dev/null)',
	       '',
	       '[ -n "$IPTABLES" -a -x "$IPTABLES" ] || startup_error "Can\'t find iptables executable"'
	       );
    }

    append_file 'params' if $config{EXPORTPARAMS};

    emitj ( '',
	    "STOPPING=",
	    'COMMENT=',        # Maintain compability with lib.base
	    '',
	    '#',
	    '# The library requires that ${VARDIR} exist',
	    '#',
	    '[ -d ${VARDIR} ] || mkdir -p ${VARDIR}'
	    );

    pop_indent;

    emit "}\n"; # End of initialize()

}

sub compile_stop_firewall() {

    emit '#
# Stop/restore the firewall after an error or because of a \'stop\' or \'clear\' command
#
stop_firewall() {

    deletechain() {
	qt $IPTABLES -L $1 -n && qt $IPTABLES -F $1 && qt $IPTABLES -X $1
    }

    deleteallchains() {
	$IPTABLES -F
	$IPTABLES -X
    }

    setcontinue() {
	$IPTABLES -A $1 -m state --state ESTABLISHED,RELATED -j ACCEPT
    }

    delete_nat() {
	$IPTABLES -t nat -F
	$IPTABLES -t nat -X

	if [ -f ${VARDIR}/nat ]; then
	    while read external interface; do
		del_ip_addr $external $interface
	    done < ${VARDIR}/nat

	    rm -f ${VARDIR}/nat
	fi
    }

    case $COMMAND in
	stop|clear)
	    ;;
	*)
	    set +x

            case $COMMAND in
	        start)
	            logger -p kern.err "ERROR:$PRODUCT start failed"
	            ;;
	        restart)
	            logger -p kern.err "ERROR:$PRODUCT restart failed"
	            ;;
	        restore)
	            logger -p kern.err "ERROR:$PRODUCT restore failed"
	            ;;
            esac

            if [ "$RESTOREFILE" = NONE ]; then
                COMMAND=clear
                clear_firewall
                echo "$PRODUCT Cleared"

	        kill $$
	        exit 2
            else
	        RESTOREPATH=${VARDIR}/$RESTOREFILE

	        if [ -x $RESTOREPATH ]; then

		    if [ -x ${RESTOREPATH}-ipsets ]; then
		        progress_message2 Restoring Ipsets...
		        #
		        # We must purge iptables to be sure that there are no
		        # references to ipsets
		        #
		        for table in mangle nat filter; do
			    $IPTABLES -t $table -F
			    $IPTABLES -t $table -X
		        done

		        ${RESTOREPATH}-ipsets
		    fi

		    echo Restoring ${PRODUCT:=Shorewall}...

		    if $RESTOREPATH restore; then
		        echo "$PRODUCT restored from $RESTOREPATH"
		        set_state "Started"
		    else
		        set_state "Unknown"
		    fi

	            kill $$
	            exit 2
	        fi
            fi
	    ;;
    esac

    set_state "Stopping"

    STOPPING="Yes"

    TERMINATOR=

    deletechain shorewall

    determine_capabilities

    run_stop_exit;

    if [ -n "$MANGLE_ENABLED" ]; then
	run_iptables -t mangle -F
	run_iptables -t mangle -X
	for chain in PREROUTING INPUT FORWARD POSTROUTING; do
	    qt $IPTABLES -t mangle -P $chain ACCEPT
	done
    fi

    if [ -n "$RAW_TABLE" ]; then
	run_iptables -t raw -F
	run_iptables -t raw -X
	for chain in PREROUTING OUTPUT; do
	    qt $IPTABLES -t raw -P $chain ACCEPT
	done
    fi

    if [ -n "$NAT_ENABLED" ]; then
	delete_nat
	for chain in PREROUTING POSTROUTING OUTPUT; do
	    qt $IPTABLES -t nat -P $chain ACCEPT
	done
    fi

    if [ -f ${VARDIR}/proxyarp ]; then
	while read address interface external haveroute; do
	    qt arp -i $external -d $address pub
	    [ -z "${haveroute}${NOROUTES}" ] && qt ip route del $address dev $interface
	done < ${VARDIR}/proxyarp

        for f in /proc/sys/net/ipv4/conf/*; do
            [ -f $f/proxy_arp ] && echo 0 > $f/proxy_arp
        done
    fi

    rm -f ${VARDIR}/proxyarp
';

    push_indent;

    emit 'delete_tc1' if $config{CLEAR_TC};

    emitj( 'undo_routing',
	   'restore_default_route' 
	   );

    my $criticalhosts = process_criticalhosts;

    if ( @$criticalhosts ) {
	if ( $config{ADMINISABSENTMINDED} ) {
	    emitj ( 'for chain in INPUT OUTPUT; do',
		    '    setpolicy $chain ACCEPT',
		    'done',
		    '',
		    'setpolicy FORWARD DROP',
		    '',
		    'deleteallchains',
		    ''
		    );

	    for my $hosts ( @$criticalhosts ) {
                my ( $interface, $host ) = ( split /:/, $hosts );
                my $source = match_source_net $host;
		my $dest   = match_dest_net $host;

		emitj( "\$IPTABLES -A INPUT  -i $interface $source -j ACCEPT",
		       "\$IPTABLES -A OUTPUT -o $interface $dest   -j ACCEPT"
		       );
	    }

	    emitj( '',
		   'for chain in INPUT OUTPUT; do',
		   '    setpolicy $chain DROP',
		   "done\n"
		   );
	  } else {
	    emitj( '',
		   'for chain in INPUT OUTPUT; do',
		   '    setpolicy \$chain ACCEPT',
		   'done',
		   '',
		   'setpolicy FORWARD DROP',
		   '',
		   "deleteallchains\n"
		   );

	    for my $hosts ( @$criticalhosts ) {
                my ( $interface, $host ) = ( split /:/, $hosts );
                my $source = match_source_net $host;
		my $dest   = match_dest_net $host;

		emitj( "\$IPTABLES -A INPUT  -i $interface $source -j ACCEPT",
		       "\$IPTABLES -A OUTPUT -o $interface $dest   -j ACCEPT"
		       );
	    }

	    emitj ( "\nsetpolicy INPUT DROP",
		    '',
		    'for chain in INPUT FORWARD; do',
		    '    setcontinue $chain',
		    "done\n"
		    );
	}
    } elsif ( $config{ADMINISABSENTMINDED} ) {
	emitj( 'for chain in INPUT FORWARD; do',
	       '    setpolicy $chain DROP',
	       'done',
	       '',
	       'setpolicy OUTPUT ACCEPT',
	       '',
	       'deleteallchains',
	       '',
	       'for chain in INPUT FORWARD; do',
	       '    setcontinue $chain',
	       "done\n",
	       );
    } else {
	emitj( 'for chain in INPUT OUTPUT FORWARD; do',
	       '    setpolicy $chain DROP',
	       'done',
	       '',
	       "deleteallchains\n"
	       );
    }

    process_routestopped;

    emitj( '$IPTABLES -A INPUT  -i lo -j ACCEPT',
	   '$IPTABLES -A OUTPUT -o lo -j ACCEPT'
	   );

    emit '$IPTABLES -A OUTPUT -o lo -j ACCEPT' unless $config{ADMINISABSENTMINDED};

    my $interfaces = find_interfaces_by_option 'dhcp';

    for my $interface ( @$interfaces ) {
	emit "\$IPTABLES -A INPUT  -p udp -i $interface --dport 67:68 -j ACCEPT";
	emit "\$IPTABLES -A OUTPUT -p udp -o $interface --dport 67:68 -j ACCEPT" unless $config{ADMINISABSENTMINDED};
	#
	# This might be a bridge
	#
	emit "\$IPTABLES -A FORWARD -p udp -i $interface -o $interface --dport 67:68 -j ACCEPT";
    }

    emit '';

    if ( $config{IP_FORWARDING} =~ /on/i ) {
	emitj( 'echo 1 > /proc/sys/net/ipv4/ip_forward',
	       'progress_message2 IP Forwarding Enabled' );
    } elsif ( $config{IP_FORWARDING} =~ /off/i ) {
	emitj( 'echo 0 > /proc/sys/net/ipv4/ip_forward',
	       'progress_message2 IP Forwarding Disabled!'
	       );
    }

    emit 'run_stopped_exit';

    pop_indent;

    emit '
    set_state "Stopped"

    logger -p kern.info "$PRODUCT Stopped"

    case $COMMAND in
    stop|clear)
	;;
    *)
	#
	# The firewall is being stopped when we were trying to do something
	# else. Kill the shell in case we\'re running in a subshell
	#
	kill $$
	;;
    esac
}
';

}

#
# Second Phase of Script Generation
#
#    copies the 'prog.functions' file into the script
#    generates the first part of 'setup_routing_and_traffic_shaping()'
#
#        The bulk of that function is produced by the various config file
#        parsing routines that are called directly out of 'compiler()'.
#
sub generate_script_2 () {

    copy $env{SHAREDIRPL} . 'prog.functions';

    emitj( '#',
	   '# Setup Routing and Traffic Shaping',
	   '#',
	   'setup_routing_and_traffic_shaping() {'
	   );

    push_indent;
    
    emit 'local restore_file=$1';

    save_progress_message 'Initializing...';
    
    if ( $ENV{EXPORT} ) {
	my $mf = find_file 'modules';

	if ( $mf ne "$env{SHAREDIR}/module" && -f $mf ) {

	    emitj( 'echo MODULESDIR="$MODULESDIR" > ${VARDIR}/.modulesdir',
		   'cat > ${VARDIR}/.modules << EOF'
		   );

	    open MF, $mf or fatal_error "Unable to open $mf: $!";

	    while ( $line = <MF> ) { emit_as_is $line if $line =~ /^\s*loadmodule\b/; }

	    close MF;

	    emit_unindented "EOF\n";

	    emit 'reload_kernel_modules < ${VARDIR}/.modules';
	} else {
	    emit 'load_kernel_modules Yes';
	}
    } else {
	emit 'load_kernel_modules Yes';
    }

    emit '';

    for my $interface ( @{find_interfaces_by_option 'norfc1918'} ) {
	emitj ( "addr=\$(ip -f inet addr show $interface 2> /dev/null | grep 'inet\ ' | head -n1)",
		'if [ -n "$addr" ]; then',
		'    addr=$(echo $addr | sed \'s/inet //;s/\/.*//;s/ peer.*//\')',
		'    for network in 10.0.0.0/8 176.16.0.0/12 192.168.0.0/16; do',
		'        if in_network $addr $network; then',
		"            error_message \"WARNING: The 'norfc1918' option has been specified on an interface with an RFC 1918 address. Interface:$interface\"",
		'        fi',
		'    done',
		"fi\n" );
    }

    emitj ( 'run_init_exit',
	    '',
	    'qt $IPTABLES -L shorewall -n && qt $IPTABLES -F shorewall && qt $IPTABLES -X shorewall',
	    '',
	    'delete_proxyarp',
	    ''
	    );
    
    emit "delete_tc1\n"            if $config{CLEAR_TC};
    emit "disable_ipv6\n"          if $config{DISABLE_IPV6};
    setup_mss( $config{CLAMPMSS} ) if $config{CLAMPMSS};

}

#
# Third (final stage of script generation).
#
#    Generate the end of 'setup_routing_and_traffic_shaping()':
#        Generate code for loading the various files in /var/lib/shorewall[-lite]
#        Generate code to add IP addresses under ADD_IP_ALIASES and ADD_SNAT_ALIASES
#    Generate the 'setup_netfilter()' function that runs iptables-restore.
#    Generate the 'define_firewall()' function.  
#
sub generate_script_3() {

    emit 'cat > ${VARDIR}/proxyarp << __EOF__';
    dump_proxy_arp;
    emit_unindented '__EOF__';

    emit 'cat > ${VARDIR}/chains << __EOF__';
    dump_rule_chains;
    emit_unindented '__EOF__';

    emit 'cat > ${VARDIR}/zones << __EOF__';
    dump_zone_contents;
    emit_unindented '__EOF__';

    emit '> ${VARDIR}/nat';

    add_addresses;

    pop_indent;

    emit "}\n";

    progress_message2 "Creating iptables-restore input...";
    create_netfilter_load;

    emit "#\n# Start/Restart the Firewall\n#";
    emit 'define_firewall() {';
    push_indent;
    emit 'setup_routing_and_traffic_shaping;

if [ $COMMAND = restore ]; then
    iptables_save_file=${VARDIR}/$(basename $0)-iptables
    if [ -f $iptables_save_file ]; then
        iptables-restore < $iptables_save_file
    else
        fatal_error "$iptables_save_file does not exist"
    fi
    set_state "Started"
else
    setup_netfilter
    restore_dynamic_rules
    run_start_exit
    $IPTABLES -N shorewall
    set_state "Started"
    run_started_exit

    cp -f $(my_pathname) ${VARDIR}/.restore
fi

date > ${VARDIR}/restarted

case $COMMAND in
    start)
        logger -p kern.info "$PRODUCT started"
        ;;
    restart)
        logger -p kern.info "$PRODUCT restarted"
        ;;
    refresh)
        logger -p kern.info "$PRODUCT refreshed"
        ;;
    restore)
        logger -p kern.info "$PRODUCT restored"
        ;;
esac';

    pop_indent;

    emit "}\n";
    
    copy $env{SHAREDIRPL} . 'prog.footer';
}

#
#  The Compiler.
#
#    If the argument is non-null, it names the script file to generate. 
#    Otherwise, this is a 'check' command and no script is produced.
#
sub compiler( $ ) {
    
    my $objectfile = $_[0];

    report_capabilities if $ENV{VERBOSE} > 1;

    fatal_error join( '', 'Shorewall-perl ', $env{VERSION}, ' requires Conntrack Match Support' )
	unless $capabilities{CONNTRACK_MATCH};
    fatal_error join ( '', 'Shorewall-perl ', $env{VERSION}, ' requires Multi-port Match Support' )
	unless $capabilities{MULTIPORT};
    fatal_error join( '', 'Shorewall-perl ', $env{VERSION}, ' requires Address Type Match Support' )
	unless $capabilities{ADDRTYPE};
    fatal_error 'MACLIST_TTL requires the Recent Match capability which is not present in your Kernel and/or iptables'
	if $config{MACLIST_TTL} && ! $capabilities{RECENT_MATCH};
    fatal_error 'RFC1918_STRICT=Yes requires Connection Tracking match'
	if $config{RFC1918_STRICT} && ! $capabilities{CONNTRACK_MATCH};
    fatal_error 'HIGH_ROUTE_MARKS=Yes requires extended MARK support'
	if $config{HIGH_ROUTE_MARKS} && ! $capabilities{XCONNMARK};
    if ( $config{MANGLE_ENABLED} ) {
	fatal_error 'Traffic Shaping requires mangle support in your kernel and iptables' unless $capabilities{MANGLE_ENABLED};
    }

    ( $command, $doing, $done ) = qw/ check Checking Checked / unless $objectfile;

    initialize_chain_table;

    if ( $command eq 'compile' ) {
	create_temp_object( $objectfile );
	generate_script_1;
    }

    #
    # Process the zones file.
    #
    progress_message2 "Determining Zones...";                    
    determine_zones;
    #
    # Process the interfaces file.
    #
    progress_message2 "Validating interfaces file...";           
    validate_interfaces_file;             
    #
    # Process the hosts file.
    #
    progress_message2 "Validating hosts file...";                
    validate_hosts_file;
    #
    # Report zone contents
    #
    progress_message "Determining Hosts in Zones...";        
    zone_report;
    #
    # Do action pre-processing.
    #
    progress_message2 "Preprocessing Action Files...";           
    process_actions1;
    #
    # Process the Policy File.
    #
    progress_message2 "Validating Policy file...";               
    validate_policy;
    #
    # Compile the 'stop_firewall()' function
    #
    compile_stop_firewall;
    #
    # Start Second Part of script
    #
    generate_script_2;
    #
    # Do all of the zone-independent stuff
    #
    progress_message2 "$doing Common Rules...";              
    add_common_rules;
    #
    # /proc stuff
    #
    setup_arp_filtering;
    setup_route_filtering;
    setup_martian_logging;
    setup_source_routing;
    setup_forwarding;
    #
    # Proxy Arp
    #
    setup_proxy_arp;
    #
    # [Re-]establish Routing
    # 
    if ( -s "$ENV{TMP_DIR}/providers" ) {
	setup_providers;
    } else {
	emit "\nundo_routing";
	emit 'restore_default_route';
    }
    #
    # TCRules and Traffic Shaping
    #
    progress_message2 "$doing TC Rules...";                  
    setup_tc;
    #
    # Setup Masquerading/SNAT
    #
    progress_message2 "$doing Masq file...";                     
    setup_masq;
    #
    # MACLIST Filtration
    #
    progress_message2 "$doing MAC Filtration -- Phase 1..."; 
    setup_mac_lists 1;
    #
    # Process the rules file.
    #
    progress_message2 "$doing Rules...";                         
    process_rules;
    #
    # Add Tunnel rules.
    #
    progress_message2 "$doing Tunnels...";                       
    setup_tunnels;
    #
    # Post-rules action processing.
    #
    process_actions2;
    process_actions3;
    #
    # MACLIST Filtration again
    #
    progress_message2 "$doing MAC Filtration -- Phase 2..."; 
    setup_mac_lists 2;
    #
    # Apply Policies
    #
    progress_message2 'Applying Policies...';                    
    apply_policy_rules;                    
    #
    # Setup Nat
    #
    progress_message2 "$doing one-to-one NAT...";                
    setup_nat;
    #
    # Setup NETMAP
    #
    progress_message2 "$doing NETMAP...";                
    setup_netmap;
    #
    # Accounting.
    #
    progress_message2 "$doing Accounting...";                
    setup_accounting;

    progress_message2 'Generating Rule Matrix...';         
    generate_matrix;
    generate_script_3;

    if ( $command eq 'check' ) {
	progress_message3 "Shorewall configuration verified";
    } else {
	#
	# Finish the script.
	#
	finalize_object;
	#
	# And generate the auxilary config file
	#
	generate_aux_config if $ENV{EXPORT};
    }
}

#
#                        E x e c u t i o n   S t a r t s   H e r e
#

#
# Get shorewall.conf and capabilities.
#
get_configuration;
#
# Compile/Check the configuration.
#
compiler $ARGV[0];