shorewall_code/Shorewall-perl/Shorewall/Nat.pm
2007-04-03 01:25:13 +00:00

433 lines
11 KiB
Perl

#
# Shorewall-perl 3.9 -- /usr/share/shorewall-perl/Shorewall/Nat.pm
#
# 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
#
#
package Shorewall::Nat;
require Exporter;
use Shorewall::Common;
use Shorewall::Config;
use Shorewall::Zones;
use Shorewall::Chains;
use Shorewall::IPAddrs;
use strict;
our @ISA = qw(Exporter);
our @EXPORT = qw( setup_masq setup_nat setup_netmap add_addresses );
our @EXPORT_OK = ();
our @VERSION = 1.00;
my @addresses_to_add;
my %addresses_to_add;
#
# Handle IPSEC Options in a masq record
#
sub do_ipsec_options($)
{
my %validoptions = ( strict => NOTHING,
next => NOTHING,
reqid => NUMERIC,
spi => NUMERIC,
proto => IPSECPROTO,
mode => IPSECMODE,
"tunnel-src" => NETWORK,
"tunnel-dst" => NETWORK,
);
my $list=$_[0];
my $options = '-m policy';
my $fmt;
for my $e ( split ',' , $list ) {
my $val = undef;
my $invert = '';
if ( $e =~ /([\w-]+)!=(.+)/ ) {
$val = $2;
$e = $1;
$invert = '! ';
} elsif ( $e =~ /([\w-]+)=(.+)/ ) {
$val = $2;
$e = $1;
}
$fmt = $validoptions{$e};
fatal_error "Invalid Option ($e)" unless $fmt;
if ( $fmt eq NOTHING ) {
fatal_error "Option $e does not take a value" if defined $val;
} else {
fatal_error "Invalid value ($val) for option \"$e\"" unless $val =~ /^($fmt)$/;
}
$options .= $invert;
$options .= "--$e";
$options .= " $val" if defined $val;
}
$options . ' ';
}
#
# Process a single rule from the the masq file
#
sub setup_one_masq($$$$$$)
{
my ($fullinterface, $networks, $addresses, $proto, $ports, $ipsec) = @_;
my $rule = '';
my $pre_nat;
my $add_snat_aliases = $config{ADD_SNAT_ALIASES};
my $destnets = '';
my $target = '-j MASQUERADE ';
#
# Handle IPSEC options, if any
#
if ( $ipsec ne '-' ) {
fatal_error "Non-empty IPSEC column requires policy match support in your kernel and iptables" unless $globals{ORIGINAL_POLICY_MATCH};
if ( $ipsec =~ /^yes$/i ) {
$rule .= '-m policy --pol ipsec --dir out ';
} elsif ( $ipsec =~ /^no$/i ) {
$rule .= '-m policy --pol none --dir out ';
} else {
$rule .= do_ipsec_options $ipsec;
}
}
#
# Leading '+'
#
if ( $fullinterface =~ /^\+/ ) {
$pre_nat = 1;
$fullinterface =~ s/\+//;
}
#
# Parse the remaining part of the INTERFACE column
#
if ( $fullinterface =~ /^([^:]+)::([^:]*)$/ ) {
$add_snat_aliases = 0;
$destnets = $2;
$fullinterface = $1;
} elsif ( $fullinterface =~ /^([^:]+:[^:]+):([^:]+)$/ ) {
$destnets = $2;
$fullinterface = $1;
} elsif ( $fullinterface =~ /^([^:]+):$/ ) {
$add_snat_aliases = 0;
$fullinterface = $1;
} elsif ( $fullinterface =~ /^([^:]+):([^:]*)$/ ) {
my ( $one, $two ) = ( $1, $2 );
if ( $2 =~ /\./ ) {
$fullinterface = $one;
$destnets = $two;
}
}
#
# Isolate and verify the interface part
#
( my $interface = $fullinterface ) =~ s/:.*//;
fatal_error "Unknown interface ($interface)" unless $interfaces{$interface}{root};
my $chainref = ensure_chain('nat', $pre_nat ? snat_chain $interface : masq_chain $interface);
#
# If there is no source or destination then allow all addresses
#
$networks = ALLIPv4 if $networks eq '-';
$destnets = ALLIPv4 if $destnets eq '-';
#
# Handle Protocol and Ports
#
$rule .= do_proto $proto, $ports, '';
my $detectaddress = 0;
#
# Parse the ADDRESSES column
#
if ( $addresses ne '-' ) {
if ( $addresses =~ /^SAME:nodst:/ ) {
$target = '-j SAME --nodst';
$addresses =~ s/.*://;
for my $addr ( split /,/, $addresses ) {
$target .= "--to $addr ";
}
} elsif ( $addresses =~ /^SAME:nodst:/ ) {
$target = '-j SAME ';
$addresses =~ s/.*://;
for my $addr ( split /,/, $addresses ) {
$target .= "--to $addr ";
}
} elsif ( $addresses eq 'detect' ) {
add_command( $chainref , 'addrlist=' );
add_command( $chainref , join( '', 'for address in ' , get_interface_addresses( $interface ), '; do' ) );
add_command( $chainref , ' addrlist="$addrlist --to-source $address"' );
add_command( $chainref , 'done' );
$target = '-j SNAT $addrlist';
} else {
my $addrlist = '';
for my $addr ( split /,/, $addresses ) {
if ( $addr =~ /^.*\..*\..*\./ ) {
$target = '-j SNAT ';
$addrlist .= "--to-source $addr ";
} else {
$addr =~ s/^://;
$addrlist .= "--to-ports $addr ";
}
}
$target .= $addrlist;
}
} else {
$add_snat_aliases = 0;
}
#
# And Generate the Rule(s)
#
expand_rule $chainref , POSTROUTE_RESTRICT , $rule, $networks, $destnets, '', $target, '', '' , '';
if ( $add_snat_aliases ) {
my ( $interface, $alias ) = split /:/, $fullinterface;
for my $address ( split /,/, $addresses ) {
my ( $addrs, $port ) = split /:/, $address;
next unless $addrs;
for my $addr ( ip_range_explicit $addrs ) {
unless ( $addresses_to_add{$addr} ) {
emit "del_ip_addr $addr $interface" unless $config{RETAIN_ALIASES};
$addresses_to_add{$addr} = 1;
if ( defined $alias ) {
push @addresses_to_add, $addr, "$interface:$alias";
$alias++;
} else {
push @addresses_to_add, $addr, $interface;
}
}
}
}
}
progress_message " Masq record \"$line\" $done";
}
#
# Process the masq file
#
sub setup_masq()
{
my $first_entry = 1;
my $fn = open_file 'masq';
while ( read_a_line ) {
my ($fullinterface, $networks, $addresses, $proto, $ports, $ipsec) = split_line 2, 6, 'masq file';
if ( $first_entry ) {
progress_message2 "$doing $fn...";
require_capability( 'NAT_ENABLED' , 'a non-empty masq file' );
$first_entry = 0;
}
if ( $fullinterface eq 'COMMENT' ) {
if ( $capabilities{COMMENTS} ) {
( $comment = $line ) =~ s/^\s*COMMENT\s*//;
$comment =~ s/\s*$//;
} else {
warning_message "COMMENT ignored -- requires comment support in iptables/Netfilter";
}
} else {
setup_one_masq $fullinterface, $networks, $addresses, $proto, $ports, $ipsec;
}
}
$comment = '';
}
#
# Validate the ALL INTERFACES or LOCAL column in the NAT file
#
sub validate_nat_column( $$ ) {
my $ref = $_[1];
my $val = $$ref;
if ( defined $val ) {
unless ( ( $val = "\L$val" ) eq 'yes' ) {
if ( ( $val eq 'no' ) || ( $val eq '-' ) ) {
$$ref = '';
} else {
fatal_error "Invalid value ($val) for $_[0]";
}
}
} else {
$$ref = '';
}
}
#
# Process a record from the NAT file
#
sub do_one_nat( $$$$$ )
{
my ( $external, $fullinterface, $internal, $allints, $localnat ) = @_;
my ( $interface, $alias ) = split /:/, $fullinterface;
sub add_nat_rule( $$ ) {
add_rule ensure_chain( 'nat', $_[0] ) , $_[1];
}
my $add_ip_aliases = $config{ADD_IP_ALIASES};
my $policyin = '';
my $policyout = '';
if ( $capabilities{POLICY_MATCH} ) {
$policyin = ' -m policy --pol none --dir in';
$policyout = '-m policy --pol none --dir out';
}
fatal_error "Invalid nat file entry" unless defined $interface && defined $internal;
if ( $add_ip_aliases ) {
if ( $interface =~ s/:$// ) {
$add_ip_aliases = '';
} else {
my ( $iface , undef ) = split /:/, $interface;
emit "del_ip_addr $external $iface" unless $config{RETAIN_ALIASES};
}
} else {
$interface =~ s/:$//;
}
validate_nat_column 'ALL INTERFACES', \$allints;
validate_nat_column 'LOCAL' , \$localnat;
if ( $allints ) {
add_nat_rule 'nat_in' , "-d $external $policyin -j DNAT --to-destination $internal";
add_nat_rule 'nat_out' , "-s $internal $policyout -j SNAT --to-source $external";
} else {
add_nat_rule input_chain( $interface ) , "-d $external $policyin -j DNAT --to-destination $internal";
add_nat_rule output_chain( $interface ) , "-s $internal $policyout -j SNAT --to-source $external";
}
add_nat_rule 'OUTPUT' , "-d $external$policyout -j DNAT --to-destination $internal " if $localnat;
if ( $add_ip_aliases ) {
unless ( $addresses_to_add{$external} ) {
$addresses_to_add{$external} = 1;
push @addresses_to_add, ( $external , $fullinterface );
}
}
progress_message " NAT entry \"$line\" $done";
}
#
# Process NAT file
#
sub setup_nat() {
my $first_entry = 1;
my $fn = open_file 'nat';
while ( read_a_line ) {
my ( $external, $interface, $internal, $allints, $localnat ) = split_line 3, 5, 'nat file';
if ( $first_entry ) {
progress_message2 "$doing $fn...";
require_capability( 'NAT_ENABLED' , 'a non-empty nat file' );
$first_entry = 0;
}
if ( $external eq 'COMMENT' ) {
if ( $capabilities{COMMENTS} ) {
( $comment = $line ) =~ s/^\s*COMMENT\s*//;
$comment =~ s/\s*$//;
} else {
warning_message "COMMENT ignored -- requires comment support in iptables/Netfilter";
}
} else {
do_one_nat $external, $interface, $internal, $allints, $localnat;
}
}
$comment = '';
}
#
# Setup Network Mapping
#
sub setup_netmap() {
my $first_entry = 1;
my $fn = open_file 'netmap';
while ( read_a_line ) {
my ( $type, $net1, $interface, $net2 ) = split_line 4, 4, 'netmap file';
if ( $first_entry ) {
progress_message2 "$doing $fn...";
require_capability( 'NAT_ENABLED' , 'a non-empty netmap file' );
$first_entry = 0;
}
if ( $type eq 'DNAT' ) {
add_rule ensure_chain( 'nat' , input_chain $interface ) , "-d $net1 -j NETMAP --to $net2";
} elsif ( $type eq 'SNAT' ) {
add_rule ensure_chain( 'nat' , output_chain $interface ) , "-s $net1 -j NETMAP --to $net2";
} else {
fatal_error "Invalid type ($type)";
}
progress_message " Network $net1 on $interface mapped to $net2 ($type)";
}
}
sub add_addresses () {
if ( @addresses_to_add ) {
my $arg = '';
while ( @addresses_to_add ) {
my $addr = shift @addresses_to_add;
my $interface = shift @addresses_to_add;
$arg = "$arg $addr $interface";
}
emit "add_ip_aliases $arg";
}
}
1;