src/ferm

   1 #!/usr/bin/perl
   2
   3 #
   4 # ferm, a firewall setup program that makes firewall rules easy!
   5 #
   6 # Copyright (C) 2001-2008 Auke Kok, Max Kellermann
   7 #
   8 # Comments, questions, greetings and additions to this program
   9 # may be sent to <ferm@foo-projects.org>
  10 #
  11
  12 #
  13 # This program is free software; you can redistribute it and/or modify
  14 # it under the terms of the GNU General Public License as published by
  15 # the Free Software Foundation; either version 2 of the License, or
  16 # (at your option) any later version.
  17 #
  18 # This program is distributed in the hope that it will be useful,
  19 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 # GNU General Public License for more details.
  22 #
  23 # You should have received a copy of the GNU General Public License
  24 # along with this program; if not, write to the Free Software
  25 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  26 #
  27
  28 # $Id$
  29
  30 BEGIN {
  31     eval { require strict; import strict; };
  32     $has_strict = not $@;
  33     if ($@) {
  34         # we need no vars.pm if there is not even strict.pm
  35         $INC{'vars.pm'} = 1;
  36         *vars::import = sub {};
  37     } else {
  38         require IO::Handle;
  39     }
  40
  41     eval { require Getopt::Long; import Getopt::Long; };
  42     $has_getopt = not $@;
  43 }
  44
  45 use vars qw($has_strict $has_getopt);
  46
  47 use vars qw($DATE $VERSION);
  48
  49 # subversion keyword magic
  50 $DATE = '$Date$' =~ m,(\d{4})-(\d\d)-(\d\d), ? $1.$2.$3 : '';
  51
  52 $VERSION = '2.0';
  53 $VERSION .= '~svn' . $DATE;
  54
  55 ## interface variables
  56 # %option = command line and other options
  57 use vars qw(%option);
  58
  59 ## hooks
  60 use vars qw(@pre_hooks @post_hooks);
  61
  62 ## parser variables
  63 # $script: current script file
  64 # @stack = ferm's parser stack containing local variables
  65 # $auto_chain = index for the next auto-generated chain
  66 use vars qw($script @stack $auto_chain);
  67
  68 ## netfilter variables
  69 # %domains = state information about all domains ("ip" and "ip6")
  70 # - initialized: domain initialization is done
  71 # - tools: hash providing the paths of the domain's tools
  72 # - previous: save file of the previous ruleset, for rollback
  73 # - tables{$name}: ferm state information about tables
  74 #   - has_builtin: whether built-in chains have been determined in this table
  75 #   - chains{$chain}: ferm state information about the chains
  76 #     - builtin: whether this is a built-in chain
  77 use vars qw(%domains);
  78
  79 ## constants
  80 use vars qw(%deprecated_keywords);
  81
  82 # keywords from ferm 1.1 which are deprecated, and the new one; these
  83 # are automatically replaced, and a warning is printed
  84 %deprecated_keywords = ( goto => 'jump',
  85                        );
  86
  87 # these hashes provide the Netfilter module definitions
  88 use vars qw(%proto_defs %match_defs %target_defs);
  89
  90 #
  91 # This subsubsystem allows you to support (most) new netfilter modules
  92 # in ferm.  Add a call to one of the "add_XY_def()" functions below.
  93 #
  94 # Ok, now about the cryptic syntax: the function "add_XY_def()"
  95 # registers a new module.  There are three kinds of modules: protocol
  96 # module (e.g. TCP, ICMP), match modules (e.g. state, physdev) and
  97 # target modules (e.g. DNAT, MARK).
  98 #
  99 # The first parameter is always the module name which is passed to
 100 # iptables with "-p", "-m" or "-j" (depending on which kind of module
 101 # this is).
 102 #
 103 # After that, you add an encoded string for each option the module
 104 # supports.  This is where it becomes tricky.
 105 #
 106 # foo           defaults to an option with one argument (which may be a ferm
 107 #               array)
 108 #
 109 # foo*0         option without any arguments
 110 #
 111 # foo=s         one argument which must not be a ferm array ('s' stands for
 112 #               'scalar')
 113 #
 114 # u32=m         an array which renders into multiple iptables options in one
 115 #               rule
 116 #
 117 # ctstate=c     one argument, if it's an array, pass it to iptables as a
 118 #               single comma separated value; example:
 119 #                 ctstate (ESTABLISHED RELATED)  translates to:
 120 #                 --ctstate ESTABLISHED,RELATED
 121 #
 122 # foo=sac       three arguments: scalar, array, comma separated; you may
 123 #               concatenate more than one letter code after the '='
 124 #
 125 # foo&bar       one argument; call the perl function '&bar()' which parses
 126 #               the argument
 127 #
 128 # !foo          negation is allowed and the '!' is written before the keyword
 129 #
 130 # foo!          same as above, but '!' is after the keyword and before the
 131 #               parameters
 132 #
 133 # to:=to-destination    makes "to" an alias for "to-destination"; you have
 134 #                       to add a declaration for option "to-destination"
 135 #
 136
 137 # add a module definition
 138 sub add_def_x {
 139     my $defs = shift;
 140     my $domain_family = shift;
 141     my $params_default = shift;
 142     my $name = shift;
 143     die if exists $defs->{$domain_family}{$name};
 144     my $def = $defs->{$domain_family}{$name} = {};
 145     foreach (@_) {
 146         my $keyword = $_;
 147         my $k = {};
 148
 149         my $params = $params_default;
 150         $params = $1 if $keyword =~ s,\*(\d+)$,,;
 151         $params = $1 if $keyword =~ s,=([acs]+|m)$,,;
 152         if ($keyword =~ s,&(\S+)$,,) {
 153             $params = eval "\\&$1";
 154             die $@ if $@;
 155         }
 156         $k->{params} = $params if $params;
 157
 158         $k->{negation} = $k->{pre_negation} = 1 if $keyword =~ s,^!,,;
 159         $k->{negation} = 1 if $keyword =~ s,!$,,;
 160
 161         $k->{alias} = [$1, $def->{keywords}{$1} || die] if $keyword =~ s,:=(\S+)$,,;
 162
 163         $def->{keywords}{$keyword} = $k;
 164     }
 165
 166     return $def;
 167 }
 168
 169 # add a protocol module definition
 170 sub add_proto_def_x(@) {
 171     my $domain_family = shift;
 172     add_def_x(\%proto_defs, $domain_family, 1, @_);
 173 }
 174
 175 # add a match module definition
 176 sub add_match_def_x(@) {
 177     my $domain_family = shift;
 178     add_def_x(\%match_defs, $domain_family, 1, @_);
 179 }
 180
 181 # add a target module definition
 182 sub add_target_def_x(@) {
 183     my $domain_family = shift;
 184     add_def_x(\%target_defs, $domain_family, 's', @_);
 185 }
 186
 187 sub add_def {
 188     my $defs = shift;
 189     add_def_x($defs, 'ip', @_);
 190 }
 191
 192 # add a protocol module definition
 193 sub add_proto_def(@) {
 194     add_def(\%proto_defs, 1, @_);
 195 }
 196
 197 # add a match module definition
 198 sub add_match_def(@) {
 199     add_def(\%match_defs, 1, @_);
 200 }
 201
 202 # add a target module definition
 203 sub add_target_def(@) {
 204     add_def(\%target_defs, 's', @_);
 205 }
 206
 207 add_proto_def 'dccp', qw(dccp-types!=c dccp-option!);
 208 add_proto_def 'mh', qw(mh-type!);
 209 add_proto_def 'icmp', qw(icmp-type!);
 210 add_proto_def 'icmpv6', qw(icmpv6-type! icmp-type:=icmpv6-type);
 211 add_proto_def 'sctp', qw(chunk-types!=sc);
 212 add_proto_def 'tcp', qw(tcp-flags!=cc !syn*0 tcp-option! mss);
 213 add_proto_def 'udp', qw();
 214
 215 add_match_def '',
 216   # --source, --destination
 217   qw(source! saddr:=source destination! daddr:=destination),
 218   # --in-interface
 219   qw(in-interface! interface:=in-interface if:=in-interface),
 220   # --out-interface
 221   qw(out-interface! outerface:=out-interface of:=out-interface),
 222   # --fragment
 223   qw(!fragment*0);
 224 add_match_def 'account', qw(aaddr=s aname=s ashort*0);
 225 add_match_def 'addrtype', qw(src-type dst-type);
 226 add_match_def 'ah', qw(ahspi! ahlen! ahres*0);
 227 add_match_def 'comment', qw(comment=s);
 228 add_match_def 'condition', qw(condition!);
 229 add_match_def 'connbytes', qw(!connbytes connbytes-dir connbytes-mode);
 230 add_match_def 'connlimit', qw(!connlimit-above connlimit-mask);
 231 add_match_def 'connmark', qw(mark);
 232 add_match_def 'conntrack', qw(ctstate=c ctproto ctorigsrc! ctorigdst!),
 233   qw(ctreplsrc! ctrepldst! ctstatus ctexpire=s);
 234 add_match_def 'dscp', qw(dscp dscp-class);
 235 add_match_def 'ecn', qw(ecn-tcp-cwr*0 ecn-tcp-ece*0 ecn-ip-ect);
 236 add_match_def 'esp', qw(espspi!);
 237 add_match_def 'eui64';
 238 add_match_def 'fuzzy', qw(lower-limit=s upper-limit=s);
 239 add_match_def 'hbh', qw(hbh-len! hbh-opts=c);
 240 add_match_def 'helper', qw(helper);
 241 add_match_def 'hl', qw(hl-eq! hl-lt=s hl-gt=s);
 242 add_match_def 'hashlimit', qw(hashlimit=s hashlimit-burst=s hashlimit-mode=s hashlimit-name=s),
 243   qw(hashlimit-htable-size=s hashlimit-htable-max=s),
 244   qw(hashlimit-htable-expire=s hashlimit-htable-gcinterval=s);
 245 add_match_def 'iprange', qw(!src-range !dst-range);
 246 add_match_def 'ipv4options', qw(ssrr*0 lsrr*0 no-srr*0 !rr*0 !ts*0 !ra*0 !any-opt*0);
 247 add_match_def 'ipv6header', qw(header!=c soft*0);
 248 add_match_def 'length', qw(length!);
 249 add_match_def 'limit', qw(limit=s limit-burst=s);
 250 add_match_def 'mac', qw(mac-source!);
 251 add_match_def 'mark', qw(mark);
 252 add_match_def 'multiport', qw(source-ports!&multiport_params),
 253   qw(destination-ports!&multiport_params ports!&multiport_params);
 254 add_match_def 'nth', qw(every counter start packet);
 255 add_match_def 'owner', qw(uid-owner gid-owner pid-owner sid-owner cmd-owner);
 256 add_match_def 'physdev', qw(physdev-in! physdev-out!),
 257   qw(!physdev-is-in*0 !physdev-is-out*0 !physdev-is-bridged*0);
 258 add_match_def 'pkttype', qw(pkt-type),
 259 add_match_def 'policy',
 260   qw(dir pol strict*0 reqid spi proto mode tunnel-src tunnel-dst next*0);
 261 add_match_def 'psd', qw(psd-weight-threshold psd-delay-threshold),
 262   qw(psd-lo-ports-weight psd-hi-ports-weight);
 263 add_match_def 'quota', qw(quota=s);
 264 add_match_def 'random', qw(average);
 265 add_match_def 'realm', qw(realm!);
 266 add_match_def 'recent', qw(name=s !set*0 !rcheck*0 !update*0 !seconds !hitcount rttl*0 rsource*0 rdest*0);
 267 add_match_def 'rt', qw(rt-type! rt-segsleft! rt-len! rt-0-res*0 rt-0-addrs=c rt-0-not-strict*0);
 268 add_match_def 'set', qw(set=sc);
 269 add_match_def 'state', qw(state=c);
 270 add_match_def 'statistic', qw(mode=s probability=s every=s packet=s);
 271 add_match_def 'string', qw(algo=s from=s to=s string hex-string);
 272 add_match_def 'tcpmss', qw(!mss);
 273 add_match_def 'time', qw(timestart=s timestop=s days=c datestart=s datestop=s),
 274   qw(!monthday=c !weekdays=c utc*0 localtz*0);
 275 add_match_def 'tos', qw(!tos);
 276 add_match_def 'ttl', qw(ttl-eq ttl-lt=s ttl-gt=s);
 277 add_match_def 'u32', qw(!u32=m);
 278
 279 add_target_def 'BALANCE', qw(to-destination to:=to-destination);
 280 add_target_def 'CLASSIFY', qw(set-class);
 281 add_target_def 'CLUSTERIP', qw(new*0 hashmode clustermac total-nodes local-node hash-init);
 282 add_target_def 'CONNMARK', qw(set-mark save-mark*0 restore-mark*0 mask);
 283 add_target_def 'CONNSECMARK', qw(save*0 restore*0);
 284 add_target_def 'DNAT', qw(to-destination=m to:=to-destination random*0);
 285 add_target_def 'DSCP', qw(set-dscp set-dscp-class);
 286 add_target_def 'ECN', qw(ecn-tcp-remove*0);
 287 add_target_def 'HL', qw(hl-set hl-dec hl-inc);
 288 add_target_def 'IPV4OPTSSTRIP';
 289 add_target_def 'LOG', qw(log-level log-prefix),
 290   qw(log-tcp-sequence*0 log-tcp-options*0 log-ip-options*0 log-uid*0);
 291 add_target_def 'MARK', qw(set-mark set-xmark and-mark or-mark xor-mark);
 292 add_target_def 'MASQUERADE', qw(to-ports random*0);
 293 add_target_def 'MIRROR';
 294 add_target_def 'NETMAP', qw(to);
 295 add_target_def 'NFLOG', qw(nflog-group nflog-prefix nflog-range nflog-threshold);
 296 add_target_def 'NFQUEUE', qw(queue-num);
 297 add_target_def 'NOTRACK';
 298 add_target_def 'REDIRECT', qw(to-ports random*0);
 299 add_target_def 'REJECT', qw(reject-with);
 300 add_target_def 'ROUTE', qw(oif iif gw continue*0 tee*0);
 301 add_target_def 'SAME', qw(to nodst*0 random*0);
 302 add_target_def 'SECMARK', qw(selctx);
 303 add_target_def 'SET', qw(add-set=sc del-set=sc);
 304 add_target_def 'SNAT', qw(to-source=m to:=to-source random*0);
 305 add_target_def 'TARPIT';
 306 add_target_def 'TCPMSS', qw(set-mss clamp-mss-to-pmtu*0);
 307 add_target_def 'TOS', qw(set-tos and-tos or-tos xor-tos);
 308 add_target_def 'TRACE';
 309 add_target_def 'TTL', qw(ttl-set ttl-dec ttl-inc);
 310 add_target_def 'ULOG', qw(ulog-nlgroup ulog-prefix ulog-cprange ulog-qthreshold);
 311
 312 add_match_def_x 'arp', '',
 313   # ip
 314   qw(source-ip! destination-ip! saddr:=source-ip daddr:=destination-ip),
 315   # mac
 316   qw(source-mac! destination-mac!),
 317   # --in-interface
 318   qw(in-interface! interface:=in-interface if:=in-interface),
 319   # --out-interface
 320   qw(out-interface! outerface:=out-interface of:=out-interface),
 321   # misc
 322   qw(h-length=s opcode=s h-type=s proto-type=s),
 323   qw(mangle-ip-s=s mangle-ip-d=s mangle-mac-s=s mangle-mac-d=s mangle-target=s);
 324
 325 add_match_def_x 'eb', '',
 326   # protocol
 327   qw(protocol! proto:=protocol),
 328   # --in-interface
 329   qw(in-interface! interface:=in-interface if:=in-interface),
 330   # --out-interface
 331   qw(out-interface! outerface:=out-interface of:=out-interface),
 332   # logical interface
 333   qw(logical-in! logical-out!),
 334   # --source, --destination
 335   qw(source! saddr:=source destination! daddr:=destination),
 336   # 802.3
 337   qw(802_3-sap! 802_3-type!),
 338   # arp
 339   qw(arp-opcode! arp-htype!=ss arp-ptype!=ss),
 340   qw(arp-ip-src! arp-ip-dst! arp-mac-src! arp-mac-dst!),
 341   # ip
 342   qw(ip-source! ip-destination! ip-tos! ip-protocol! ip-sport! ip-dport!),
 343   # mark_m
 344   qw(mark!),
 345   # pkttype
 346   qw(pkttype-type!),
 347   # stp
 348   qw(stp-type! stp-flags! stp-root-prio! stp-root-addr! stp-root-cost!),
 349   qw(stp-sender-prio! stp-sender-addr! stp-port! stp-msg-age! stp-max-age!),
 350   qw(stp-hello-time! stp-forward-delay!),
 351   # vlan
 352   qw(vlan-id! vlan-prio! vlan-encap!),
 353   # log
 354   qw(log*0 log-level=s log-prefix=s log-ip*0 log-arp*0);
 355
 356 add_target_def_x 'eb', 'arpreply', qw(arpreply-mac arpreply-target);
 357 add_target_def_x 'eb', 'dnat', qw(to-destination dnat-target);
 358 add_target_def_x 'eb', 'mark', qw(set-mark mark-target);
 359 add_target_def_x 'eb', 'redirect', qw(redirect-target);
 360 add_target_def_x 'eb', 'snat', qw(to-source snat-target);
 361
 362 # import-ferm uses the above tables
 363 return 1 if $0 =~ /import-ferm$/;
 364
 365 # parameter parser for ipt_multiport
 366 sub multiport_params {
 367     my $fw = shift;
 368
 369     # multiport only allows 15 ports at a time. For this
 370     # reason, we do a little magic here: split the ports
 371     # into portions of 15, and handle these portions as
 372     # array elements
 373
 374     my $proto = $fw->{protocol};
 375     error('To use multiport, you have to specify "proto tcp" or "proto udp" first')
 376       unless defined $proto and grep { /^(?:tcp|udp|udplite)$/ } to_array($proto);
 377
 378     my $value = getvalues(undef, undef,
 379                           allow_negation => 1,
 380                           allow_array_negation => 1);
 381     if (ref $value and ref $value eq 'ARRAY') {
 382         my @value = @$value;
 383         my @params;
 384
 385         while (@value) {
 386             push @params, join(',', splice(@value, 0, 15));
 387         }
 388
 389         return @params == 1
 390           ? $params[0]
 391             : \@params;
 392     } else {
 393         return join_value(',', $value);
 394     }
 395 }
 396
 397 # initialize stack: command line definitions
 398 unshift @stack, {};
 399
 400 # Get command line stuff
 401 if ($has_getopt) {
 402     my ($opt_noexec, $opt_flush, $opt_noflush, $opt_lines, $opt_interactive,
 403         $opt_help,
 404         $opt_version, $opt_test, $opt_fast, $opt_shell,
 405         $opt_domain);
 406
 407     Getopt::Long::Configure('bundling', 'auto_help', 'no_ignore_case',
 408                             'no_auto_abbrev');
 409
 410     sub opt_def {
 411         my ($opt, $value) = @_;
 412         die 'Invalid --def specification'
 413           unless $value =~ /^\$?(\w+)=(.*)$/s;
 414         my ($name, $unparsed_value) = ($1, $2);
 415         my $tokens = tokenize_string($unparsed_value);
 416         my $value = getvalues(\&next_array_token, $tokens);
 417         die 'Extra tokens after --def'
 418           if @$tokens > 0;
 419         $stack[0]{vars}{$name} = $value;
 420     }
 421
 422     local $SIG{__WARN__} = sub { die $_[0]; };
 423     GetOptions('noexec|n' => \$opt_noexec,
 424                'flush|F' => \$opt_flush,
 425                'noflush' => \$opt_noflush,
 426                'lines|l' => \$opt_lines,
 427                'interactive|i' => \$opt_interactive,
 428                'help|h' => \$opt_help,
 429                'version|V' => \$opt_version,
 430                test => \$opt_test,
 431                remote => \$opt_test,
 432                fast => \$opt_fast,
 433                shell => \$opt_shell,
 434                'domain=s' => \$opt_domain,
 435                'def=s' => \&opt_def,
 436               );
 437
 438     if (defined $opt_help) {
 439         require Pod::Usage;
 440         Pod::Usage::pod2usage(-exitstatus => 0);
 441     }
 442
 443     if (defined $opt_version) {
 444         printversion();
 445         exit 0;
 446     };
 447
 448     $option{noexec} = $opt_noexec || $opt_test;
 449     $option{flush} = $opt_flush;
 450     $option{noflush} = $opt_noflush;
 451     $option{lines} = $opt_lines || $opt_test || $opt_shell;
 452     $option{interactive} = $opt_interactive && !$opt_noexec;
 453     $option{test} = $opt_test;
 454     $option{fast} = $opt_fast || $opt_shell;
 455     $option{shell} = $opt_shell;
 456
 457     mydie('ferm interactive mode not possible: /dev/stdin is not a tty')
 458       if $option{interactive} and not -t STDIN;
 459     mydie('ferm interactive mode not possible: /dev/stderr is not a tty')
 460       if $option{interactive} and not -t STDERR;
 461
 462     $option{domain} = $opt_domain if defined $opt_domain;
 463 } else {
 464     # tiny getopt emulation for microperl
 465     my $filename;
 466     foreach (@ARGV) {
 467         if ($_ eq '--noexec' or $_ eq '-n') {
 468             $option{noexec} = 1;
 469         } elsif ($_ eq '--lines' or $_ eq '-l') {
 470             $option{lines} = 1;
 471         } elsif ($_ eq '--fast') {
 472             $option{fast} = 1;
 473         } elsif ($_ eq '--test') {
 474             $option{test} = 1;
 475             $option{noexec} = 1;
 476             $option{lines} = 1;
 477         } elsif ($_ eq '--shell') {
 478             $option{$_} = 1 foreach qw(shell fast lines);
 479         } elsif (/^-/) {
 480             printf STDERR "Usage: ferm [--noexec] [--lines] [--fast] [--shell] FILENAME\n";
 481             exit 1;
 482         } else {
 483             $filename = $_;
 484         }
 485     }
 486     undef @ARGV;
 487     push @ARGV, $filename;
 488 }
 489
 490 unless (@ARGV == 1) {
 491     require Pod::Usage;
 492     Pod::Usage::pod2usage(-exitstatus => 1);
 493 }
 494
 495 if ($has_strict) {
 496     open LINES, ">&STDOUT" if $option{lines};
 497     open STDOUT, ">&STDERR" if $option{shell};
 498 } else {
 499     # microperl can't redirect file handles
 500     *LINES = *STDOUT;
 501
 502     if ($option{fast} and not $option{noexec}) {
 503         print STDERR "Sorry, ferm on microperl does not allow --fast without --noexec\n";
 504         exit 1
 505     }
 506 }
 507
 508 unshift @stack, {};
 509 open_script($ARGV[0]);
 510
 511 # parse all input recursively
 512 enter(0);
 513 die unless @stack == 2;
 514
 515 # execute all generated rules
 516 my $status;
 517
 518 foreach my $cmd (@pre_hooks) {
 519     print LINES "$cmd\n" if $option{lines};
 520     system($cmd) unless $option{noexec};
 521 }
 522
 523 while (my ($domain, $domain_info) = each %domains) {
 524     next unless $domain_info->{enabled};
 525     my $s = $option{fast} &&
 526       defined $domain_info->{tools}{'tables-restore'}
 527       ? execute_fast($domain, $domain_info)
 528         : execute_slow($domain, $domain_info);
 529     $status = $s if defined $s;
 530 }
 531
 532 foreach my $cmd (@post_hooks) {
 533     print "$cmd\n" if $option{lines};
 534     system($cmd) unless $option{noexec};
 535 }
 536
 537 if (defined $status) {
 538     rollback();
 539     exit $status;
 540 }
 541
 542 # ask user, and rollback if there is no confirmation
 543
 544 confirm_rules() or rollback() if $option{interactive};
 545
 546 exit 0;
 547
 548 # end of program execution!
 549
 550
 551 # funcs
 552
 553 sub printversion {
 554     print "ferm $VERSION\n";
 555     print "Copyright (C) 2001-2008 Auke Kok, Max Kellermann\n";
 556     print "This program is free software released under GPLv2.\n";
 557     print "See the included COPYING file for license details.\n";
 558 }
 559
 560
 561 sub mydie {
 562     print STDERR @_;
 563     print STDERR "\n";
 564     exit 1;
 565 }
 566
 567
 568 sub error {
 569     # returns a nice formatted error message, showing the
 570     # location of the error.
 571     my $tabs = 0;
 572     my @lines;
 573     my $l = 0;
 574     my @words = map { @$_ } @{$script->{past_tokens}};
 575
 576     for my $w ( 0 .. $#words ) {
 577         if ($words[$w] eq "\x29")
 578             { $l++ ; $lines[$l] = "    " x ($tabs-- -1) ;};
 579         if ($words[$w] eq "\x28")
 580             { $l++ ; $lines[$l] = "    " x $tabs++ ;};
 581         if ($words[$w] eq "\x7d")
 582             { $l++ ; $lines[$l] = "    " x ($tabs-- -1) ;};
 583         if ($words[$w] eq "\x7b")
 584             { $l++ ; $lines[$l] = "    " x $tabs++ ;};
 585         if ( $l > $#lines ) { $lines[$l] = "" };
 586         $lines[$l] .= $words[$w] . " ";
 587         if ($words[$w] eq "\x28")
 588             { $l++ ; $lines[$l] = "    " x $tabs ;};
 589         if (($words[$w] eq "\x29") && ($words[$w+1] ne "\x7b"))
 590             { $l++ ; $lines[$l] = "    " x $tabs ;};
 591         if ($words[$w] eq "\x7b")
 592             { $l++ ; $lines[$l] = "    " x $tabs ;};
 593         if (($words[$w] eq "\x7d") && ($words[$w+1] ne "\x7d"))
 594             { $l++ ; $lines[$l] = "    " x $tabs ;};
 595         if (($words[$w] eq "\x3b") && ($words[$w+1] ne "\x7d"))
 596             { $l++ ; $lines[$l] = "    " x $tabs ;}
 597         if ($words[$w-1] eq "option")
 598             { $l++ ; $lines[$l] = "    " x $tabs ;}
 599     }
 600     my $start = $#lines - 4;
 601     if ($start < 0) { $start = 0 } ;
 602     print STDERR "Error in $script->{filename} line $script->{line}:\n";
 603     for $l ( $start .. $#lines)
 604         { print STDERR $lines[$l]; if ($l != $#lines ) {print STDERR "\n"} ; };
 605     print STDERR "<--\n";
 606     mydie(@_);
 607 }
 608
 609 # print a warning message about code from an input file
 610 sub warning {
 611     print STDERR "Warning in $script->{filename} line $script->{line}: "
 612       . (shift) . "\n";
 613 }
 614
 615 sub find_tool($) {
 616     my $name = shift;
 617     return $name if $option{test};
 618     for my $path ('/sbin', split ':', $ENV{PATH}) {
 619         my $ret = "$path/$name";
 620         return $ret if -x $ret;
 621     }
 622     die "$name not found in PATH\n";
 623 }
 624
 625 sub initialize_domain {
 626     my $domain = shift;
 627     my $domain_info = $domains{$domain} ||= {};
 628
 629     return if exists $domain_info->{initialized};
 630
 631     die "Invalid domain '$domain'\n" unless $domain =~ /^(?:ip6?|arp|eb)$/;
 632
 633     my @tools = qw(tables);
 634     push @tools, qw(tables-save tables-restore)
 635       if $domain =~ /^ip6?$/;
 636
 637     # determine the location of this domain's tools
 638     my %tools = map { $_ => find_tool($domain . $_) } @tools;
 639     $domain_info->{tools} = \%tools;
 640
 641     # make tables-save tell us about the state of this domain
 642     # (which tables and chains do exist?), also remember the old
 643     # save data which may be used later by the rollback function
 644     local *SAVE;
 645     if (!$option{test} &&
 646         exists $tools{'tables-save'} &&
 647         open(SAVE, "$tools{'tables-save'}|")) {
 648         my $save = '';
 649
 650         my $table_info;
 651         while (<SAVE>) {
 652             $save .= $_;
 653
 654             if (/^\*(\w+)/) {
 655                 my $table = $1;
 656                 $table_info = $domain_info->{tables}{$table} ||= {};
 657             } elsif (defined $table_info and /^:(\w+)\s+(\S+)/
 658                      and $2 ne '-') {
 659                 $table_info->{chains}{$1}{builtin} = 1;
 660                 $table_info->{has_builtin} = 1;
 661             }
 662         }
 663
 664         # for rollback
 665         $domain_info->{previous} = $save;
 666     }
 667
 668     $domain_info->{initialized} = 1;
 669 }
 670
 671 # split the an input string into words and delete comments
 672 sub tokenize_string($) {
 673     my $string = shift;
 674
 675     my @ret;
 676
 677     foreach my $word ($string =~ m/(".*?"|'.*?'|`.*?`|[!,=&\$\%\(\){};]|[-+\w\/\.:]+|@\w+|#)/g) {
 678         last if $word eq '#';
 679         push @ret, $word;
 680     }
 681
 682     return \@ret;
 683 }
 684
 685 # shift an array; helper function to be passed to &getvar / &getvalues
 686 sub next_array_token {
 687     my $array = shift;
 688     shift @$array;
 689 }
 690
 691 # read some more tokens from the input file into a buffer
 692 sub prepare_tokens() {
 693     my $tokens = $script->{tokens};
 694     while (@$tokens == 0) {
 695         my $handle = $script->{handle};
 696         my $line = <$handle>;
 697         return unless defined $line;
 698
 699         $script->{line} ++;
 700
 701         # the next parser stage eats this
 702         push @$tokens, @{tokenize_string($line)};
 703     }
 704
 705     return 1;
 706 }
 707
 708 # open a ferm sub script
 709 sub open_script($) {
 710     my $filename = shift;
 711
 712     for (my $s = $script; defined $s; $s = $s->{parent}) {
 713         mydie("Circular reference in $script->{filename} line $script->{line}: $filename")
 714           if $s->{filename} eq $filename;
 715     }
 716
 717     local *FILE;
 718     open FILE, "<$filename"
 719       or mydie("Failed to open $filename: $!");
 720     my $handle = *FILE;
 721
 722     $script = { filename => $filename,
 723                 handle => $handle,
 724                 line => 0,
 725                 past_tokens => [],
 726                 tokens => [],
 727                 parent => $script,
 728               };
 729
 730     return $script;
 731 }
 732
 733 # collect script filenames which are being included
 734 sub collect_filenames(@) {
 735     my @ret;
 736
 737     # determine the current script's parent directory for relative
 738     # file names
 739     die unless defined $script;
 740     my $parent_dir = $script->{filename} =~ m,^(.*/),
 741       ? $1 : './';
 742
 743     foreach my $pathname (@_) {
 744         # non-absolute file names are relative to the parent script's
 745         # file name
 746         $pathname = $parent_dir . $pathname
 747           unless $pathname =~ m,^/,;
 748
 749         if ($pathname =~ m,/$,) {
 750             # include all regular files in a directory
 751
 752             error("'$pathname' is not a directory")
 753               unless -d $pathname;
 754
 755             local *DIR;
 756             opendir DIR, $pathname
 757               or error("Failed to open directory '$pathname': $!");
 758             my @names = readdir DIR;
 759             closedir DIR;
 760
 761             # sort those names for a well-defined order
 762             foreach my $name (sort { $a cmp $b } @names) {
 763                 # don't include hidden and backup files
 764                 next if /^\.|~$/;
 765
 766                 my $filename = $pathname . $name;
 767                 push @ret, $filename
 768                   if -f $filename;
 769             }
 770         } elsif ($pathname =~ m,\|$,) {
 771             # run a program and use its output
 772             push @ret, $pathname;
 773         } elsif ($pathname =~ m,^\|,) {
 774             error('This kind of pipe is not allowed');
 775         } else {
 776             # include a regular file
 777
 778             error("'$pathname' is a directory; maybe use trailing '/' to include a directory?")
 779               if -d $pathname;
 780             error("'$pathname' is not a file")
 781               unless -f $pathname;
 782
 783             push @ret, $pathname;
 784         }
 785     }
 786
 787     return @ret;
 788 }
 789
 790 # peek a token from the queue, but don't remove it
 791 sub peek_token() {
 792     return unless prepare_tokens();
 793     return $script->{tokens}[0];
 794 }
 795
 796 # get a token from the queue
 797 sub next_token() {
 798     return unless prepare_tokens();
 799     my $token = shift @{$script->{tokens}};
 800
 801     # update $script->{past_tokens}
 802     my $past_tokens = $script->{past_tokens};
 803
 804     if (@$past_tokens > 0) {
 805         my $prev_token = $past_tokens->[-1][-1];
 806         $past_tokens->[-1] = @$past_tokens > 1 ? ['{'] : []
 807           if $prev_token eq ';';
 808         pop @$past_tokens
 809           if $prev_token eq '}';
 810     }
 811
 812     push @$past_tokens, [] if $token eq '{' or @$past_tokens == 0;
 813     push @{$past_tokens->[-1]}, $token;
 814
 815     # return
 816     return $token;
 817 }
 818
 819 sub expect_token($;$) {
 820     my $expect = shift;
 821     my $msg = shift;
 822     my $token = next_token();
 823     error($msg || "'$expect' expected")
 824       unless defined $token and $token eq $expect;
 825 }
 826
 827 # require that another token exists, and that it's not a "special"
 828 # token, e.g. ";" and "{"
 829 sub require_next_token {
 830     my $code = shift || \&next_token;
 831
 832     my $token = &$code(@_);
 833
 834     error('unexpected end of file')
 835       unless defined $token;
 836
 837     error("'$token' not allowed here")
 838       if $token =~ /^[;{}]$/;
 839
 840     return $token;
 841 }
 842
 843 # return the value of a variable
 844 sub variable_value($) {
 845     my $name = shift;
 846
 847     foreach (@stack) {
 848         return $_->{vars}{$name}
 849           if exists $_->{vars}{$name};
 850     }
 851
 852     return $stack[0]{auto}{$name}
 853       if exists $stack[0]{auto}{$name};
 854
 855     return;
 856 }
 857
 858 # determine the value of a variable, die if the value is an array
 859 sub string_variable_value($) {
 860     my $name = shift;
 861     my $value = variable_value($name);
 862
 863     error("variable '$name' must be a string, but it is an array")
 864       if ref $value;
 865
 866     return $value;
 867 }
 868
 869 # similar to the built-in "join" function, but also handle negated
 870 # values in a special way
 871 sub join_value($$) {
 872     my ($expr, $value) = @_;
 873
 874     unless (ref $value) {
 875         return $value;
 876     } elsif (ref $value eq 'ARRAY') {
 877         return join($expr, @$value);
 878     } elsif (ref $value eq 'negated') {
 879         # bless'negated' is a special marker for negated values
 880         $value = join_value($expr, $value->[0]);
 881         return bless [ $value ], 'negated';
 882     } else {
 883         die;
 884     }
 885 }
 886
 887 # returns the next parameter, which may either be a scalar or an array
 888 sub getvalues {
 889     my ($code, $param) = (shift, shift);
 890     my %options = @_;
 891
 892     my $token = require_next_token($code, $param);
 893
 894     if ($token eq '(') {
 895         # read an array until ")"
 896         my @wordlist;
 897
 898         for (;;) {
 899             $token = getvalues($code, $param,
 900                                parenthesis_allowed => 1,
 901                                comma_allowed => 1);
 902
 903             unless (ref $token) {
 904                 last if $token eq ')';
 905
 906                 if ($token eq ',') {
 907                     error('Comma is not allowed within arrays, please use only a space');
 908                     next;
 909                 }
 910
 911                 push @wordlist, $token;
 912             } elsif (ref $token eq 'ARRAY') {
 913                 push @wordlist, @$token;
 914             } else {
 915                 error('unknown toke type');
 916             }
 917         }
 918
 919         error('empty array not allowed here')
 920           unless @wordlist or not $options{non_empty};
 921
 922         return @wordlist == 1
 923           ? $wordlist[0]
 924             : \@wordlist;
 925     } elsif ($token =~ /^\`(.*)\`$/s) {
 926         # execute a shell command, insert output
 927         my $command = $1;
 928         my $output = `$command`;
 929         unless ($? == 0) {
 930             if ($? == -1) {
 931                 error("failed to execute: $!");
 932             } elsif ($? & 0x7f) {
 933                 error("child died with signal " . ($? & 0x7f));
 934             } elsif ($? >> 8) {
 935                 error("child exited with status " . ($? >> 8));
 936             }
 937         }
 938
 939         # remove comments
 940         $output =~ s/#.*//mg;
 941
 942         # tokenize
 943         my @tokens = grep { length } split /\s+/s, $output;
 944
 945         my @values;
 946         while (@tokens) {
 947             my $value = getvalues(\&next_array_token, \@tokens);
 948             push @values, to_array($value);
 949         }
 950
 951         # and recurse
 952         return @values == 1
 953           ? $values[0]
 954             : \@values;
 955     } elsif ($token =~ /^\'(.*)\'$/s) {
 956         # single quotes: a string
 957         return $1;
 958     } elsif ($token =~ /^\"(.*)\"$/s) {
 959         # double quotes: a string with escapes
 960         $token = $1;
 961         $token =~ s,\$(\w+),string_variable_value($1),eg;
 962         return $token;
 963     } elsif ($token eq '!') {
 964         error('negation is not allowed here')
 965           unless $options{allow_negation};
 966
 967         $token = getvalues($code, $param);
 968
 969         error('it is not possible to negate an array')
 970           if ref $token and not $options{allow_array_negation};
 971
 972         return bless [ $token ], 'negated';
 973     } elsif ($token eq ',') {
 974         return $token
 975           if $options{comma_allowed};
 976
 977         error('comma is not allowed here');
 978     } elsif ($token eq '=') {
 979         error('equals operator ("=") is not allowed here');
 980     } elsif ($token eq '$') {
 981         my $name = require_next_token($code, $param);
 982         error('variable name expected - if you want to concatenate strings, try using double quotes')
 983           unless $name =~ /^\w+$/;
 984
 985         my $value = variable_value($name);
 986
 987         error("no such variable: \$$name")
 988           unless defined $value;
 989
 990         return $value;
 991     } elsif ($token eq '&') {
 992         error("function calls are not allowed as keyword parameter");
 993     } elsif ($token eq ')' and not $options{parenthesis_allowed}) {
 994         error('Syntax error');
 995     } elsif ($token =~ /^@/) {
 996         if ($token eq '@resolve') {
 997             my @params = get_function_params();
 998             error('Usage: @resolve((hostname ...))')
 999               unless @params == 1;
1000             eval { require Net::DNS; };
1001             error('For the @resolve() function, you need the Perl library Net::DNS')
1002               if $@;
1003             my $type = 'A';
1004             my $resolver = new Net::DNS::Resolver;
1005             my @result;
1006             foreach my $hostname (to_array($params[0])) {
1007                 my $query = $resolver->search($hostname, $type);
1008                 error("DNS query for '$hostname' failed: " . $resolver->errorstring)
1009                   unless $query;
1010                 foreach my $rr ($query->answer) {
1011                     next unless $rr->type eq $type;
1012                     push @result, $rr->address;
1013                 }
1014             }
1015             return \@result;
1016         } else {
1017             error("unknown ferm built-in function");
1018         }
1019     } else {
1020         return $token;
1021     }
1022 }
1023
1024 # returns the next parameter, but only allow a scalar
1025 sub getvar {
1026     my $token = getvalues(@_);
1027
1028     error('array not allowed here')
1029       if ref $token and ref $token eq 'ARRAY';
1030
1031     return $token;
1032 }
1033
1034 sub get_function_params(%) {
1035     expect_token('(', 'function name must be followed by "()"');
1036
1037     my $token = peek_token();
1038     if ($token eq ')') {
1039         require_next_token;
1040         return;
1041     }
1042
1043     my @params;
1044
1045     while (1) {
1046         if (@params > 0) {
1047             $token = require_next_token();
1048             last
1049               if $token eq ')';
1050
1051             error('"," expected')
1052               unless $token eq ',';
1053         }
1054
1055         push @params, getvalues(undef, undef, @_);
1056     }
1057
1058     return @params;
1059 }
1060
1061 # collect all tokens in a flat array reference until the end of the
1062 # command is reached
1063 sub collect_tokens() {
1064     my @level;
1065     my @tokens;
1066
1067     while (1) {
1068         my $keyword = next_token();
1069         error('unexpected end of file within function/variable declaration')
1070           unless defined $keyword;
1071
1072         if ($keyword =~ /^[\{\(]$/) {
1073             push @level, $keyword;
1074         } elsif ($keyword =~ /^[\}\)]$/) {
1075             my $expected = $keyword;
1076             $expected =~ tr/\}\)/\{\(/;
1077             my $opener = pop @level;
1078             error("unmatched '$keyword'")
1079               unless defined $opener and $opener eq $expected;
1080         } elsif ($keyword eq ';' and @level == 0) {
1081             last;
1082         }
1083
1084         push @tokens, $keyword;
1085
1086         last
1087           if $keyword eq '}' and @level == 0;
1088     }
1089
1090     return \@tokens;
1091 }
1092
1093
1094 # returns the specified value as an array. dereference arrayrefs
1095 sub to_array($) {
1096     my $value = shift;
1097     die unless wantarray;
1098     die if @_;
1099     unless (ref $value) {
1100         return $value;
1101     } elsif (ref $value eq 'ARRAY') {
1102         return @$value;
1103     } else {
1104         die;
1105     }
1106 }
1107
1108 # evaluate the specified value as bool
1109 sub eval_bool($) {
1110     my $value = shift;
1111     die if wantarray;
1112     die if @_;
1113     unless (ref $value) {
1114         return $value;
1115     } elsif (ref $value eq 'ARRAY') {
1116         return @$value > 0;
1117     } else {
1118         die;
1119     }
1120 }
1121
1122 sub is_netfilter_core_target($) {
1123     my $target = shift;
1124     die unless defined $target and length $target;
1125
1126     return $target =~ /^(?:ACCEPT|DROP|RETURN|QUEUE)$/;
1127 }
1128
1129 sub is_netfilter_module_target($$) {
1130     my ($domain_family, $target) = @_;
1131     die unless defined $target and length $target;
1132
1133     return defined $domain_family &&
1134       exists $target_defs{$domain_family} &&
1135         $target_defs{$domain_family}{$target};
1136 }
1137
1138 sub is_netfilter_builtin_chain($$) {
1139     my ($table, $chain) = @_;
1140
1141     return grep { $_ eq $chain }
1142       qw(PREROUTING INPUT FORWARD OUTPUT POSTROUTING);
1143 }
1144
1145 sub netfilter_canonical_protocol($) {
1146     my $proto = shift;
1147     return 'icmpv6'
1148       if $proto eq 'ipv6-icmp';
1149     return 'mh'
1150       if $proto eq 'ipv6-mh';
1151     return $proto;
1152 }
1153
1154 sub netfilter_protocol_module($) {
1155     my $proto = shift;
1156     return unless defined $proto;
1157     return 'icmp6'
1158       if $proto eq 'icmpv6';
1159     return $proto;
1160 }
1161
1162 # escape the string in a way safe for the shell
1163 sub shell_escape($) {
1164     my $token = shift;
1165
1166     return $token if $token =~ /^[-_a-zA-Z0-9]+$/s;
1167
1168     if ($option{fast}) {
1169         # iptables-save/iptables-restore are quite buggy concerning
1170         # escaping and special characters... we're trying our best
1171         # here
1172
1173         $token =~ s,",',g;
1174         $token = '"' . $token . '"'
1175           if $token =~ /[\s\'\\;&]/s;
1176     } else {
1177         return $token
1178           if $token =~ /^\`.*\`$/;
1179         $token =~ s/'/\\'/g;
1180         $token = '\'' . $token . '\''
1181           if $token =~ /[\s\"\\;<>&|]/s;
1182     }
1183
1184     return $token;
1185 }
1186
1187 # append an option to the shell command line, using information from
1188 # the module definition (see %match_defs etc.)
1189 sub shell_append_option($$$) {
1190     my ($ref, $keyword, $value) = @_;
1191
1192     if (ref $value) {
1193         if (ref $value eq 'negated') {
1194             $value = $value->[0];
1195             $keyword .= ' !';
1196         } elsif (ref $value eq 'pre_negated') {
1197             $value = $value->[0];
1198             $$ref .= ' !';
1199         }
1200     }
1201
1202     unless (defined $value) {
1203         $$ref .= " --$keyword";
1204     } elsif (ref $value) {
1205         if (ref $value eq 'params') {
1206             $$ref .= " --$keyword ";
1207             $$ref .= join(' ', map { shell_escape($_) } @$value);
1208         } elsif (ref $value eq 'multi') {
1209             foreach (@$value) {
1210                 $$ref .= " --$keyword " . shell_escape($_);
1211             }
1212         } else {
1213             die;
1214         }
1215     } else {
1216         $$ref .= " --$keyword " . shell_escape($value);
1217     }
1218 }
1219
1220 sub transform_rule($$) {
1221     my ($domain, $rule) = @_;
1222
1223     $rule->{options}[$rule->{protocol_index}][1] = 'icmpv6'
1224       if $domain eq 'ip6' and $rule->{protocol} eq 'icmp';
1225 }
1226
1227 sub printrule($$$) {
1228     my ($domain, $chain_rules, $rule) = @_;
1229
1230     transform_rule($domain, $rule);
1231
1232     # return if this is a declaration-only rule
1233     return if $option{flush} or not $rule->{has_rule};
1234
1235     # format iptables options
1236     my $rr = '';
1237     foreach my $option (@{$rule->{options}}) {
1238         shell_append_option(\$rr, $option->[0], $option->[1]);
1239     }
1240
1241     # append to rule list
1242     push @$chain_rules, { rule => $rr,
1243                           script => $rule->{script},
1244                         };
1245 }
1246
1247 sub check_unfold(\@$$) {
1248     my ($unfold, $parent, $key) = @_;
1249
1250     return unless ref $parent->{$key} and
1251       ref $parent->{$key} eq 'ARRAY';
1252
1253     push @$unfold, $parent, $key, $parent->{$key};
1254 }
1255
1256 sub mkrules2($$$) {
1257     my ($domain, $chain_rules, $fw) = @_;
1258
1259     my @unfold;
1260     foreach my $option (@{$fw->{options}}) {
1261         push @unfold, $option
1262           if ref $option->[1] and ref $option->[1] eq 'ARRAY';
1263     }
1264
1265     if (@unfold == 0) {
1266         printrule($domain, $chain_rules, $fw);
1267         return;
1268     }
1269
1270     sub dofr {
1271         my $fw = shift;
1272         my ($domain, $chain_rules) = (shift, shift);
1273         my $option = shift;
1274         my @values = @{$option->[1]};
1275
1276         foreach my $value (@values) {
1277             $option->[1] = $value;
1278             $fw->{protocol} = $value if $option->[0] eq 'protocol';
1279
1280             if (@_) {
1281                 dofr($fw, $domain, $chain_rules, @_);
1282             } else {
1283                 printrule($domain, $chain_rules, $fw);
1284             }
1285         }
1286     }
1287
1288     dofr($fw, $domain, $chain_rules, @unfold);
1289 }
1290
1291 # convert a bunch of internal rule structures in iptables calls,
1292 # unfold arrays during that
1293 sub mkrules($) {
1294     my $fw = shift;
1295
1296     foreach my $domain (to_array $fw->{domain}) {
1297         my $domain_info = $domains{$domain};
1298         $domain_info->{enabled} = 1;
1299
1300         foreach my $table (to_array $fw->{table}) {
1301             my $table_info = $domain_info->{tables}{$table} ||= {};
1302
1303             foreach my $chain (to_array $fw->{chain}) {
1304                 my $chain_rules = $table_info->{chains}{$chain}{rules} ||= [];
1305                 mkrules2($domain, $chain_rules, $fw);
1306             }
1307         }
1308     }
1309 }
1310
1311 sub filter_domains($) {
1312     my $domains = shift;
1313     my $result = [];
1314
1315     foreach my $domain (to_array $domains) {
1316         next if exists $option{domain}
1317           and $domain ne $option{domain};
1318
1319         eval {
1320             initialize_domain($domain);
1321         };
1322         error($@) if $@;
1323
1324         push @$result, $domain;
1325     }
1326
1327     return @$result == 1 ? $result->[0] : $result;
1328 }
1329
1330 # parse a keyword from a module definition
1331 sub parse_keyword($$$$) {
1332     my ($current, $def, $keyword, $negated_ref) = @_;
1333
1334     my $params = $def->{params};
1335
1336     my $value;
1337
1338     my $negated;
1339     if ($$negated_ref && exists $def->{pre_negation}) {
1340         $negated = 1;
1341         undef $$negated_ref;
1342     }
1343
1344     unless (defined $params) {
1345         undef $value;
1346     } elsif (ref $params && ref $params eq 'CODE') {
1347         $value = &$params($current);
1348     } elsif ($params eq 'm') {
1349         $value = bless [ to_array getvalues() ], 'multi';
1350     } elsif ($params =~ /^[a-z]/) {
1351         if (exists $def->{negation} and not $negated) {
1352             my $token = peek_token();
1353             if ($token eq '!') {
1354                 require_next_token;
1355                 $negated = 1;
1356             }
1357         }
1358
1359         my @params;
1360         foreach my $p (split(//, $params)) {
1361             if ($p eq 's') {
1362                 push @params, getvar();
1363             } elsif ($p eq 'c') {
1364                 my @v = to_array getvalues(undef, undef,
1365                                            non_empty => 1);
1366                 push @params, join(',', @v);
1367             } else {
1368                 die;
1369             }
1370         }
1371
1372         $value = @params == 1
1373           ? $params[0]
1374             : bless \@params, 'params';
1375     } elsif ($params == 1) {
1376         if (exists $def->{negation} and not $negated) {
1377             my $token = peek_token();
1378             if ($token eq '!') {
1379                 require_next_token;
1380                 $negated = 1;
1381             }
1382         }
1383
1384         $value = getvalues();
1385
1386         warning("log-prefix is too long; truncating to 29 characters: '$1'")
1387           if $keyword eq 'log-prefix' && $value =~ s,^(.{29}).+$,$1,;
1388     } else {
1389         if (exists $def->{negation} and not $negated) {
1390             my $token = peek_token();
1391             if ($token eq '!') {
1392                 require_next_token;
1393                 $negated = 1;
1394             }
1395         }
1396
1397         $value = bless [ map {
1398             getvar()
1399         } (1..$params) ], 'params';
1400     }
1401
1402     $value = bless [ $value ], exists $def->{pre_negation} ? 'pre_negated' : 'negated'
1403       if $negated;
1404
1405     return $value;
1406 }
1407
1408 sub append_option(\%$$) {
1409     my ($rule, $name, $value) = @_;
1410     push @{$rule->{options}}, [ $name, $value ];
1411 }
1412
1413 # parse options of a module
1414 sub parse_option($$$$) {
1415     my ($def, $current, $keyword, $negated_ref) = @_;
1416
1417     while (exists $def->{alias}) {
1418         ($keyword, $def) = @{$def->{alias}};
1419         die unless defined $def;
1420     }
1421
1422     append_option(%$current, $keyword,
1423                   parse_keyword($current, $def, $keyword, $negated_ref));
1424     return 1;
1425 }
1426
1427 sub copy_on_write($$) {
1428     my ($rule, $key) = @_;
1429     return unless exists $rule->{cow}{$key};
1430     $rule->{$key} = {%{$rule->{$key}}};
1431     delete $rule->{cow}{$key};
1432 }
1433
1434 sub new_level(\%$) {
1435     my ($current, $prev) = @_;
1436
1437     %$current = ();
1438     if (defined $prev) {
1439         # copy data from previous level
1440         $current->{cow} = { keywords => 1, };
1441         $current->{keywords} = $prev->{keywords};
1442         $current->{match} = { %{$prev->{match}} };
1443         $current->{options} = [@{$prev->{options}}];
1444         foreach my $key (qw(domain domain_family table chain protocol protocol_index has_action)) {
1445             $current->{$key} = $prev->{$key}
1446               if exists $prev->{$key};
1447         }
1448     } else {
1449         $current->{cow} = {};
1450         $current->{keywords} = {};
1451         $current->{match} = {};
1452         $current->{options} = [];
1453     }
1454 }
1455
1456 sub merge_keywords(\%$) {
1457     my ($rule, $keywords) = @_;
1458     copy_on_write($rule, 'keywords');
1459     while (my ($name, $def) = each %$keywords) {
1460         $rule->{keywords}{$name} = $def;
1461     }
1462 }
1463
1464 sub set_domain(\%$) {
1465     my ($rule, $domain) = @_;
1466
1467     my $filtered_domain = filter_domains($domain);
1468     my $domain_family;
1469     unless (ref $domain) {
1470         $domain_family = $domain eq 'ip6' ? 'ip' : $domain;
1471     } elsif (@$domain == 0) {
1472         $domain_family = 'none';
1473     } elsif (grep { not /^ip6?$/s } @$domain) {
1474         error('Cannot combine non-IP domains');
1475     } else {
1476         $domain_family = 'ip';
1477     }
1478
1479     $rule->{domain_family} = $domain_family;
1480     $rule->{keywords} = $match_defs{$domain_family}{''}{keywords};
1481     $rule->{cow}{keywords} = 1;
1482
1483     $rule->{domain} = $stack[0]{auto}{DOMAIN} = $filtered_domain;
1484 }
1485
1486 sub set_module_target(\%$$) {
1487     my ($rule, $name, $defs) = @_;
1488
1489     if ($name eq 'TCPMSS') {
1490         my $protos = $rule->{protocol};
1491         error('No protocol specified before TCPMSS')
1492           unless defined $protos;
1493         foreach my $proto (to_array $protos) {
1494             error('TCPMSS not available for protocol "$proto"')
1495               unless $proto eq 'tcp';
1496         }
1497     }
1498
1499     merge_keywords(%$rule, $defs->{keywords});
1500 }
1501
1502 # the main parser loop: read tokens, convert them into internal rule
1503 # structures
1504 sub enter($$) {
1505     my $lev = shift;  # current recursion depth
1506     my $prev = shift; # previous rule hash
1507
1508     # enter is the core of the firewall setup, it is a
1509     # simple parser program that recognizes keywords and
1510     # retreives parameters to set up the kernel routing
1511     # chains
1512
1513     my $base_level = $script->{base_level} || 0;
1514     die if $base_level > $lev;
1515
1516     my %current;
1517     new_level(%current, $prev);
1518
1519     # read keywords 1 by 1 and dump into parser
1520     while (defined (my $keyword = next_token())) {
1521         # check if the current rule should be negated
1522         my $negated = $keyword eq '!';
1523         if ($negated) {
1524             # negation. get the next word which contains the 'real'
1525             # rule
1526             $keyword = getvar();
1527
1528             error('unexpected end of file after negation')
1529               unless defined $keyword;
1530         }
1531
1532         # the core: parse all data
1533         for ($keyword)
1534         {
1535             # deprecated keyword?
1536             if (exists $deprecated_keywords{$keyword}) {
1537                 my $new_keyword = $deprecated_keywords{$keyword};
1538                 warning("'$keyword' is deprecated, please use '$new_keyword' instead");
1539                 $keyword = $new_keyword;
1540             }
1541
1542             # effectuation operator
1543             if ($keyword eq ';') {
1544                 if ($current{has_rule} and not exists $current{has_action}) {
1545                     # something is wrong when a rule was specified,
1546                     # but no action
1547                     error('No action defined; did you mean "NOP"?');
1548                 }
1549
1550                 error('No chain defined') unless exists $current{chain};
1551
1552                 $current{script} = { filename => $script->{filename},
1553                                      line => $script->{line},
1554                                    };
1555
1556                 mkrules(\%current);
1557
1558                 # and clean up variables set in this level
1559                 new_level(%current, $prev);
1560
1561                 next;
1562             }
1563
1564             # conditional expression
1565             if ($keyword eq '@if') {
1566                 unless (eval_bool(getvalues)) {
1567                     collect_tokens;
1568                     my $token = peek_token();
1569                     require_next_token() if $token and $token eq '@else';
1570                 }
1571
1572                 next;
1573             }
1574
1575             if ($keyword eq '@else') {
1576                 # hack: if this "else" has not been eaten by the "if"
1577                 # handler above, we believe it came from an if clause
1578                 # which evaluated "true" - remove the "else" part now.
1579                 collect_tokens;
1580                 next;
1581             }
1582
1583             # hooks for custom shell commands
1584             if ($keyword eq 'hook') {
1585                 error('"hook" must be the first token in a command')
1586                   if exists $current{domain};
1587
1588                 my $position = getvar();
1589                 my $hooks;
1590                 if ($position eq 'pre') {
1591                     $hooks = \@pre_hooks;
1592                 } elsif ($position eq 'post') {
1593                     $hooks = \@post_hooks;
1594                 } else {
1595                     error("Invalid hook position: '$position'");
1596                 }
1597
1598                 push @$hooks, getvar();
1599
1600                 expect_token(';');
1601                 next;
1602             }
1603
1604             # recursing operators
1605             if ($keyword eq '{') {
1606                 # push stack
1607                 my $old_stack_depth = @stack;
1608
1609                 unshift @stack, { auto => { %{$stack[0]{auto} || {}} } };
1610
1611                 # recurse
1612                 enter($lev + 1, \%current);
1613
1614                 # pop stack
1615                 shift @stack;
1616                 die unless @stack == $old_stack_depth;
1617
1618                 # after a block, the command is finished, clear this
1619                 # level
1620                 new_level(%current, $prev);
1621
1622                 next;
1623             }
1624
1625             if ($keyword eq '}') {
1626                 error('Unmatched "}"')
1627                   if $lev <= $base_level;
1628
1629                 # consistency check: check if they havn't forgotten
1630                 # the ';' before the last statement
1631                 error('Missing semicolon before "}"')
1632                   if $current{has_rule};
1633
1634                 # and exit
1635                 return;
1636             }
1637
1638             # include another file
1639             if ($keyword eq '@include' or $keyword eq 'include') {
1640                 my @files = collect_filenames to_array getvalues;
1641                 $keyword = next_token;
1642                 error('Missing ";" - "include FILENAME" must be the last command in a rule')
1643                   unless defined $keyword and $keyword eq ';';
1644
1645                 foreach my $filename (@files) {
1646                     # save old script, open new script
1647                     my $old_script = $script;
1648                     open_script($filename);
1649                     $script->{base_level} = $lev + 1;
1650
1651                     # push stack
1652                     my $old_stack_depth = @stack;
1653
1654                     my $stack = {};
1655
1656                     if (@stack > 0) {
1657                         # include files may set variables for their parent
1658                         $stack->{vars} = ($stack[0]{vars} ||= {});
1659                         $stack->{functions} = ($stack[0]{functions} ||= {});
1660                         $stack->{auto} = { %{ $stack[0]{auto} || {} } };
1661                     }
1662
1663                     unshift @stack, $stack;
1664
1665                     # parse the script
1666                     enter($lev + 1, \%current);
1667
1668                     # pop stack
1669                     shift @stack;
1670                     die unless @stack == $old_stack_depth;
1671
1672                     # restore old script
1673                     $script = $old_script;
1674                 }
1675
1676                 next;
1677             }
1678
1679             # definition of a variable or function
1680             if ($keyword eq '@def' or $keyword eq 'def') {
1681                 error('"def" must be the first token in a command')
1682                   if $current{has_rule};
1683
1684                 my $type = require_next_token();
1685                 if ($type eq '$') {
1686                     my $name = require_next_token();
1687                     error('invalid variable name')
1688                       unless $name =~ /^\w+$/;
1689
1690                     expect_token('=');
1691
1692                     my $value = getvalues(undef, undef, allow_negation => 1);
1693
1694                     expect_token(';');
1695
1696                     $stack[0]{vars}{$name} = $value
1697                       unless exists $stack[-1]{vars}{$name};
1698                 } elsif ($type eq '&') {
1699                     my $name = require_next_token();
1700                     error('invalid function name')
1701                       unless $name =~ /^\w+$/;
1702
1703                     expect_token('(', 'function parameter list or "()" expected');
1704
1705                     my @params;
1706                     while (1) {
1707                         my $token = require_next_token();
1708                         last if $token eq ')';
1709
1710                         if (@params > 0) {
1711                             error('"," expected')
1712                               unless $token eq ',';
1713
1714                             $token = require_next_token();
1715                         }
1716
1717                         error('"$" and parameter name expected')
1718                           unless $token eq '$';
1719
1720                         $token = require_next_token();
1721                         error('invalid function parameter name')
1722                           unless $token =~ /^\w+$/;
1723
1724                         push @params, $token;
1725                     }
1726
1727                     my %function;
1728
1729                     $function{params} = \@params;
1730
1731                     expect_token('=');
1732
1733                     my $tokens = collect_tokens();
1734                     $function{block} = 1 if grep { $_ eq '{' } @$tokens;
1735                     $function{tokens} = $tokens;
1736
1737                     $stack[0]{functions}{$name} = \%function
1738                       unless exists $stack[-1]{functions}{$name};
1739                 } else {
1740                     error('"$" (variable) or "&" (function) expected');
1741                 }
1742
1743                 next;
1744             }
1745
1746             # def references
1747             if ($keyword eq '$') {
1748                 error('variable references are only allowed as keyword parameter');
1749             }
1750
1751             if ($keyword eq '&') {
1752                 my $name = require_next_token;
1753                 error('function name expected')
1754                   unless $name =~ /^\w+$/;
1755
1756                 my $function;
1757                 foreach (@stack) {
1758                     $function = $_->{functions}{$name};
1759                     last if defined $function;
1760                 }
1761                 error("no such function: \&$name")
1762                   unless defined $function;
1763
1764                 my $paramdef = $function->{params};
1765                 die unless defined $paramdef;
1766
1767                 my @params = get_function_params(allow_negation => 1);
1768
1769                 error("Wrong number of parameters for function '\&$name': "
1770                       . @$paramdef . " expected, " . @params . " given")
1771                   unless @params == @$paramdef;
1772
1773                 my %vars;
1774                 for (my $i = 0; $i < @params; $i++) {
1775                     $vars{$paramdef->[$i]} = $params[$i];
1776                 }
1777
1778                 if ($function->{block}) {
1779                     # block {} always ends the current rule, so if the
1780                     # function contains a block, we have to require
1781                     # the calling rule also ends here
1782                     expect_token(';');
1783                 }
1784
1785                 my @tokens = @{$function->{tokens}};
1786                 for (my $i = 0; $i < @tokens; $i++) {
1787                     if ($tokens[$i] eq '$' and $i + 1 < @tokens and
1788                         exists $vars{$tokens[$i + 1]}) {
1789                         my @value = to_array($vars{$tokens[$i + 1]});
1790                         @value = ('(', @value, ')')
1791                           unless @tokens == 1;
1792                         splice(@tokens, $i, 2, @value);
1793                         $i += @value - 2;
1794                     } elsif ($tokens[$i] =~ m,^"(.*)"$,) {
1795                         $tokens[$i] =~ s,\$(\w+),exists $vars{$1} ? $vars{$1} : "\$$1",eg;
1796                     }
1797                 }
1798
1799                 unshift @{$script->{tokens}}, @tokens;
1800
1801                 next;
1802             }
1803
1804             # where to put the rule?
1805             if ($keyword eq 'domain') {
1806                 error('Domain is already specified')
1807                   if exists $current{domain};
1808
1809                 set_domain(%current, getvalues());
1810                 next;
1811             }
1812
1813             if ($keyword eq 'table') {
1814                 error('Table is already specified')
1815                   if exists $current{table};
1816                 $current{table} = $stack[0]{auto}{TABLE} = getvalues();
1817
1818                 set_domain(%current, 'ip')
1819                   unless exists $current{domain};
1820
1821                 next;
1822             }
1823
1824             if ($keyword eq 'chain') {
1825                 error('Chain is already specified')
1826                   if exists $current{chain};
1827                 $current{chain} = $stack[0]{auto}{CHAIN} = getvalues();
1828
1829                 # ferm 1.1 allowed lower case built-in chain names
1830                 foreach (ref $current{chain} ? @{$current{chain}} : $current{chain}) {
1831                     error('Please write built-in chain names in upper case')
1832                       if /^(?:input|forward|output|prerouting|postrouting)$/;
1833                 }
1834
1835                 set_domain(%current, 'ip')
1836                   unless exists $current{domain};
1837
1838                 $current{table} = 'filter'
1839                   unless exists $current{table};
1840
1841                 next;
1842             }
1843
1844             error('Chain must be specified')
1845               unless exists $current{chain};
1846
1847             # policy for built-in chain
1848             if ($keyword eq 'policy') {
1849                 error('Cannot specify matches for policy')
1850                   if $current{has_rule};
1851
1852                 my $policy = getvar();
1853                 error("Invalid policy target: $policy")
1854                   unless $policy =~ /^(?:ACCEPT|DROP)$/;
1855
1856                 expect_token(';');
1857
1858                 foreach my $domain (to_array $current{domain}) {
1859                     foreach my $table (to_array $current{table}) {
1860                         foreach my $chain (to_array $current{chain}) {
1861                             $domains{$domain}{tables}{$table}{chains}{$chain}{policy} = $policy;
1862                         }
1863                     }
1864                 }
1865
1866                 new_level(%current, $prev);
1867                 next;
1868             }
1869
1870             # create a subchain
1871             if ($keyword eq '@subchain' or $keyword eq 'subchain') {
1872                 error('Chain must be specified')
1873                   unless exists $current{chain};
1874
1875                 error('No rule specified before "@subchain"')
1876                   unless $current{has_rule};
1877
1878                 my $subchain;
1879                 $keyword = next_token();
1880
1881                 if ($keyword =~ /^(["'])(.*)\1$/s) {
1882                     $subchain = $2;
1883                     $keyword = next_token();
1884                 } else {
1885                     $subchain = 'ferm_auto_' . ++$auto_chain;
1886                 }
1887
1888                 error('"{" or chain name expected after "@subchain"')
1889                   unless $keyword eq '{';
1890
1891                 # create a deep copy of %current, only containing values
1892                 # which must be in the subchain
1893                 my %inner = ( cow => { keywords => 1, },
1894                               keywords => $current{keywords},
1895                               match => {},
1896                               options => [],
1897                             );
1898                 $inner{domain} = $current{domain};
1899                 $inner{domain_family} = $current{domain_family};
1900                 $inner{table} = $current{table};
1901                 $inner{chain} = $inner{auto}{CHAIN} = $subchain;
1902
1903                 if (exists $current{protocol}) {
1904                     $inner{protocol} = $current{protocol};
1905                     $inner{protocol_index} = 0;
1906                     append_option(%inner, 'protocol', $inner{protocol});
1907                 }
1908
1909                 # enter the block
1910                 enter(1, \%inner);
1911
1912                 # now handle the parent - it's a jump to the sub chain
1913                 $current{has_action} = 1;
1914                 append_option(%current, 'jump', $subchain);
1915
1916                 $current{script} = { filename => $script->{filename},
1917                                      line => $script->{line},
1918                                    };
1919
1920                 mkrules(\%current);
1921
1922                 # and clean up variables set in this level
1923                 new_level(%current, $prev);
1924
1925                 next;
1926             }
1927
1928             # everything else must be part of a "real" rule, not just
1929             # "policy only"
1930             $current{has_rule}++;
1931
1932             # extended parameters:
1933             if ($keyword =~ /^mod(?:ule)?$/) {
1934                 foreach my $module (to_array getvalues) {
1935                     next if exists $current{match}{$module};
1936
1937                     my $domain_family = $current{domain_family};
1938                     my $defs = $match_defs{$domain_family}{$module};
1939
1940                     append_option(%current, 'match', $module);
1941                     $current{match}{$module} = 1;
1942
1943                     merge_keywords(%current, $defs->{keywords})
1944                       if defined $defs;
1945                 }
1946
1947                 next;
1948             }
1949
1950             # keywords from $current{keywords}
1951
1952             if (exists $current{keywords}{$keyword}) {
1953                 my $def = $current{keywords}{$keyword};
1954                 parse_option($def, \%current, $keyword, \$negated);
1955                 next;
1956             }
1957
1958             ###
1959             # actions
1960             #
1961
1962             # jump action
1963             if ($keyword eq 'jump') {
1964                 error('There can only one action per rule')
1965                   if exists $current{has_action};
1966                 my $chain = getvar();
1967                 if (my $defs = is_netfilter_module_target($current{domain_family}, $chain)) {
1968                     set_module_target(%current, $chain, $defs);
1969                 }
1970                 $current{has_action} = 1;
1971                 append_option(%current, 'jump', $chain);
1972                 next;
1973             };
1974
1975             # goto action
1976             if ($keyword eq 'realgoto') {
1977                 error('There can only one action per rule')
1978                   if exists $current{has_action};
1979                 append_option(%current, 'goto', getvar());
1980                 $current{has_action} = 1;
1981                 next;
1982             };
1983
1984             # action keywords
1985             if (is_netfilter_core_target($keyword)) {
1986                 error('There can only one action per rule')
1987                   if exists $current{has_action};
1988                 $current{has_action} = 1;
1989                 append_option(%current, 'jump', $keyword);
1990                 next;
1991             }
1992
1993             if ($keyword eq 'NOP') {
1994                 error('There can only one action per rule')
1995                   if exists $current{has_action};
1996                 $current{has_action} = 1;
1997                 next;
1998             }
1999
2000             if (my $defs = is_netfilter_module_target($current{domain_family}, $keyword)) {
2001                 error('There can only one action per rule')
2002                   if exists $current{has_action};
2003
2004                 set_module_target(%current, $keyword, $defs);
2005                 $current{has_action} = 1;
2006                 append_option(%current, 'jump', $keyword);
2007                 next;
2008             }
2009
2010             my $proto = $current{protocol};
2011
2012             ###
2013             # protocol specific options
2014             #
2015
2016             if ($keyword eq 'proto') {
2017                 my $protocol = parse_keyword(\%current,
2018                                              { params => 1, negation => 1 },
2019                                              'proto', \$negated);
2020                 $current{protocol} = $protocol;
2021                 $current{protocol_index} = scalar(@{$current{options}});
2022                 append_option(%current, 'protocol', $current{protocol});
2023
2024                 unless (ref $protocol) {
2025                     $protocol = netfilter_canonical_protocol($protocol);
2026                     my $domain_family = $current{domain_family};
2027                     my $defs = $proto_defs{$domain_family}{$protocol};
2028                     if (defined $defs) {
2029                         merge_keywords(%current, $defs->{keywords});
2030                         my $module = netfilter_protocol_module($protocol);
2031                         $current{match}{$module} = 1;
2032                     }
2033                 }
2034                 next;
2035             }
2036
2037             # port switches
2038             if ($keyword =~ /^[sd]port$/) {
2039                 error('To use sport or dport, you have to specify "proto tcp" or "proto udp" first')
2040                   unless defined $proto and grep { /^(?:tcp|udp|udplite|dccp|sctp)$/ } to_array $proto;
2041
2042                 append_option(%current, $keyword,
2043                               getvalues(undef, undef,
2044                                         allow_negation => 1));
2045                 next;
2046             }
2047
2048             # default
2049             error("Unrecognized keyword: $keyword");
2050         }
2051
2052         # if the rule didn't reset the negated flag, it's not
2053         # supported
2054         error("Doesn't support negation: $keyword")
2055           if $negated;
2056     }
2057
2058     error('Missing "}" at end of file')
2059       if $lev > $base_level;
2060
2061     # consistency check: check if they havn't forgotten
2062     # the ';' before the last statement
2063     error("Missing semicolon before end of file")
2064       if exists $current{domain};
2065 }
2066
2067 sub execute_command {
2068     my ($command, $script) = @_;
2069
2070     print LINES "$command\n"
2071       if $option{lines};
2072     return if $option{noexec};
2073
2074     my $ret = system($command);
2075     unless ($ret == 0) {
2076         if ($? == -1) {
2077             print STDERR "failed to execute: $!\n";
2078             exit 1;
2079         } elsif ($? & 0x7f) {
2080             printf STDERR "child died with signal %d\n", $? & 0x7f;
2081             return 1;
2082         } else {
2083             print STDERR "(rule declared in $script->{filename}:$script->{line})\n"
2084               if defined $script;
2085             return $? >> 8;
2086         }
2087     }
2088
2089     return;
2090 }
2091
2092 sub execute_slow($$) {
2093     my ($domain, $domain_info) = @_;
2094
2095     my $domain_cmd = $domain_info->{tools}{tables};
2096
2097     my $status;
2098     while (my ($table, $table_info) = each %{$domain_info->{tables}}) {
2099         my $table_cmd = "$domain_cmd -t $table";
2100
2101         # reset chain policies
2102         while (my ($chain, $chain_info) = each %{$table_info->{chains}}) {
2103             next unless $chain_info->{builtin} or
2104               (not $table_info->{has_builtin} and
2105                is_netfilter_builtin_chain($table, $chain));
2106             $status ||= execute_command("$table_cmd -P $chain ACCEPT")
2107               unless $option{noflush};
2108         }
2109
2110         # clear
2111         unless ($option{noflush}) {
2112             $status ||= execute_command("$table_cmd -F");
2113             $status ||= execute_command("$table_cmd -X");
2114         }
2115
2116         next if $option{flush};
2117
2118         # create chains / set policy
2119         while (my ($chain, $chain_info) = each %{$table_info->{chains}}) {
2120             if (exists $chain_info->{policy}) {
2121                 $status ||= execute_command("$table_cmd -P $chain $chain_info->{policy}")
2122                   unless $chain_info->{policy} eq 'ACCEPT';
2123             } elsif (not is_netfilter_builtin_chain($table, $chain)) {
2124                 $status ||= execute_command("$table_cmd -N $chain");
2125             }
2126         }
2127
2128         # dump rules
2129         while (my ($chain, $chain_info) = each %{$table_info->{chains}}) {
2130             my $chain_cmd = "$table_cmd -A $chain";
2131             foreach my $rule (@{$chain_info->{rules}}) {
2132                 $status ||= execute_command($chain_cmd . $rule->{rule});
2133             }
2134         }
2135     }
2136
2137     return $status;
2138 }
2139
2140 sub rules_to_save($$) {
2141     my ($domain, $domain_info) = @_;
2142
2143     # convert this into an iptables-save text
2144     my $result = "# Generated by ferm $VERSION on " . localtime() . "\n";
2145
2146     while (my ($table, $table_info) = each %{$domain_info->{tables}}) {
2147         # select table
2148         $result .= '*' . $table . "\n";
2149
2150         # create chains / set policy
2151         foreach my $chain (sort keys %{$table_info->{chains}}) {
2152             my $chain_info = $table_info->{chains}{$chain};
2153             my $policy = $option{flush} ? 'ACCEPT' : $chain_info->{policy};
2154             unless (defined $policy) {
2155                 if (is_netfilter_builtin_chain($table, $chain)) {
2156                     $policy = 'ACCEPT';
2157                 } else {
2158                     $policy = '-';
2159                 }
2160             }
2161             $result .= ":$chain $policy\ [0:0]\n";
2162         }
2163
2164         next if $option{flush};
2165
2166         # dump rules
2167         foreach my $chain (sort keys %{$table_info->{chains}}) {
2168             my $chain_info = $table_info->{chains}{$chain};
2169             foreach my $rule (@{$chain_info->{rules}}) {
2170                 $result .= "-A $chain$rule->{rule}\n";
2171             }
2172         }
2173
2174         # do it
2175         $result .= "COMMIT\n";
2176     }
2177
2178     return $result;
2179 }
2180
2181 sub restore_domain($$) {
2182     my ($domain, $save) = @_;
2183
2184     my $path = $domains{$domain}{tools}{'tables-restore'};
2185
2186     local *RESTORE;
2187     open RESTORE, "|$path"
2188       or die "Failed to run $path: $!\n";
2189
2190     print RESTORE $save;
2191
2192     close RESTORE
2193       or die "Failed to run $path\n";
2194 }
2195
2196 sub execute_fast($$) {
2197     my ($domain, $domain_info) = @_;
2198
2199     my $save = rules_to_save($domain, $domain_info);
2200
2201     if ($option{lines}) {
2202         print LINES "$domain_info->{tools}{'tables-restore'} <<EOT\n"
2203           if $option{shell};
2204         print LINES $save;
2205         print LINES "EOT\n"
2206           if $option{shell};
2207     }
2208
2209     return if $option{noexec};
2210
2211     eval {
2212         restore_domain($domain, $save);
2213     };
2214     if ($@) {
2215         print STDERR $@;
2216         return 1;
2217     }
2218
2219     return;
2220 }
2221
2222 sub rollback() {
2223     my $error;
2224     while (my ($domain, $domain_info) = each %domains) {
2225         next unless $domain_info->{enabled};
2226         unless (defined $domain_info->{tools}{'tables-restore'}) {
2227             print STDERR "Cannot rollback domain '$domain' because there is no ${domain}tables-restore\n";
2228             next;
2229         }
2230
2231         my $reset = '';
2232         while (my ($table, $table_info) = each %{$domain_info->{tables}}) {
2233             my $reset_chain = '';
2234             foreach my $chain (keys %{$table_info->{chains}{$table}}) {
2235                 next unless is_netfilter_builtin_chain($table, $chain);
2236                 $reset_chain .= ":${chain} ACCEPT [0:0]\n";
2237             }
2238             $reset .= "*${table}\n${reset_chain}COMMIT\n"
2239               if length $reset_chain;
2240         }
2241
2242         $reset .= $domain_info->{previous}
2243           if defined $domain_info->{previous};
2244
2245         restore_domain($domain, $reset);
2246     }
2247
2248     print STDERR "\nFirewall rules rolled back.\n" unless $error;
2249     exit 1;
2250 }
2251
2252 sub alrm_handler {
2253     # do nothing, just interrupt a system call
2254 }
2255
2256 sub confirm_rules() {
2257     $SIG{ALRM} = \&alrm_handler;
2258
2259     alarm(5);
2260
2261     print STDERR "\n"
2262       . "ferm has applied the new firewall rules.\n"
2263         . "Please type 'yes' to confirm:\n";
2264     STDERR->flush();
2265
2266     alarm(30);
2267
2268     my $line = '';
2269     STDIN->sysread($line, 3);
2270
2271     eval {
2272         require POSIX;
2273         POSIX::tcflush(*STDIN, 2);
2274     };
2275     print STDERR "$@" if $@;
2276
2277     $SIG{ALRM} = 'DEFAULT';
2278
2279     return $line eq 'yes';
2280 }
2281
2282 # end of ferm
2283
2284 __END__
2285
2286 =head1 NAME
2287
2288 ferm - a firewall rule parser for linux
2289
2290 =head1 SYNOPSIS
2291
2292 B<ferm> I<options> I<inputfiles>
2293
2294 =head1 OPTIONS
2295
2296  -n, --noexec      Do not execute the rules, just simulate
2297  -F, --flush       Flush all netfilter tables managed by ferm
2298  -l, --lines       Show all rules that were created
2299  -i, --interactive Interactive mode: revert if user does not confirm
2300  --remote          Remote mode; ignore host specific configuration.
2301                    This implies --noexec and --lines.
2302  -V, --version     Show current version number
2303  -h, --help        Look at this text
2304  --fast            Generate an iptables-save file, used by iptables-restore
2305  --shell           Generate a shell script which calls iptables-restore
2306  --domain {ip|ip6} Handle only the specified domain
2307  --def '$name=v'   Override a variable
2308
2309 =cut