dist/ipf/perl/ipfmeta.pl

   1 #!/usr/bin/perl -w
   2 #
   3 # Written by Camiel Dobbelaar <cd@sentia.nl>, Aug-2000
   4 # ipfmeta is in the Public Domain.
   5 #
   6
   7 use strict;
   8 use Getopt::Std;
   9
  10 ## PROCESS COMMANDLINE
  11 our($opt_v); $opt_v=1;
  12 getopts('v:') || die "usage: ipfmeta [-v verboselevel] [objfile]\n";
  13 my $verbose = $opt_v + 0;
  14 my $objfile = shift || "ipf.objs";
  15 my $MAXRECURSION = 10;
  16
  17 ## READ OBJECTS
  18 open(FH, "$objfile") || die "cannot open $objfile: $!\n";
  19 my @tokens;
  20 while (<FH>) {
  21         chomp;
  22         s/#.*$//;       # remove comments
  23         s/^\s+//;       # compress whitespace
  24         s/\s+$//;
  25         next if m/^$/;  # skip empty lines
  26         push (@tokens, split);
  27 }
  28 close(FH) || die "cannot close $objfile: $!\n";
  29 # link objects with their values
  30 my $obj="";
  31 my %objs;
  32 while (@tokens) {
  33         my $token = shift(@tokens);
  34         if ($token =~ m/^\[([^]]*)\]$/) {
  35                 # new object
  36                 $obj = $1;
  37         } else {
  38                 # new value
  39                 push(@{$objs{$obj}}, $token) unless ($obj eq "");
  40         }
  41 }
  42
  43 # sort objects: longest first
  44 my @objs = sort { length($b) <=> length($a) } keys %objs;
  45
  46 ## SUBSTITUTE OBJECTS WITH THEIR VALUES FROM STDIN
  47 foreach (<STDIN>) {
  48         foreach (expand($_, 0)) {
  49                 print;
  50         }
  51 }
  52
  53 ## END
  54
  55 sub expand {
  56         my $line = shift;
  57         my $level = shift;
  58         my @retlines = $line;
  59         my $obj;
  60         my $val;
  61
  62         # coarse protection
  63         if ($level > $MAXRECURSION) {
  64                 print STDERR "ERR: recursion exceeds $MAXRECURSION levels\n";
  65                 return;
  66         }
  67
  68         foreach $obj (@objs) {
  69                 if ($line =~ m/$obj/) {
  70                         @retlines = "";
  71                         if ($level < $verbose) {
  72                                 # add metarule as a comment
  73                                 push(@retlines, "# ".$line);
  74                         }
  75                         foreach $val (@{$objs{$obj}}) {
  76                                 my $newline = $line;
  77                                 $newline =~ s/$obj/$val/;
  78                                 push(@retlines, expand($newline, $level+1));
  79                         }
  80                         last;
  81                 }
  82         }
  83
  84         return @retlines;
  85 }
  86
  87 __END__
  88
  89 =head1 NAME
  90
  91 B<ipfmeta> - use objects in IP filter files
  92
  93 =head1 SYNOPSIS
  94
  95 B<ipfmeta> [F<options>] [F<objfile>]
  96
  97 =head1 DESCRIPTION
  98
  99 B<ipfmeta> is used to simplify the maintenance of your IP filter
 100 ruleset. It does this through the use of 'objects'.  A matching
 101 object gets replaced by its values at runtime.  This is similar to
 102 what a macro processor like m4 does.
 103
 104 B<ipfmeta> is specifically geared towards IP filter. It is line
 105 oriented, if an object has multiple values, the line with the object
 106 is duplicated and substituted for each value. It is also recursive,
 107 an object may have another object as a value.
 108
 109 Rules to be processed are read from stdin, output goes to stdout.
 110
 111 The verbose option allows for the inclusion of the metarules in the
 112 output as comments.
 113
 114 Definition of the objects and their values is done in a separate
 115 file, the filename defaults to F<ipf.objs>.  An object is delimited
 116 by square brackets. A value is delimited by whitespace.  Comments
 117 start with '#' and end with a newline. Empty lines and extraneous
 118 whitespace are allowed.  A value belongs to the first object that
 119 precedes it.
 120
 121 It is recommended that you use all caps or another distinguishing
 122 feature for object names. You can use B<ipfmeta> for NAT rules also,
 123 for instance to keep them in sync with filter rules.  Combine
 124 B<ipfmeta> with a Makefile to save typing.
 125
 126 =head1 OPTIONS
 127
 128 =over 4
 129
 130 =item B<-v> I<verboselevel>
 131
 132 Include metarules in output as comments. Default is 1, the top level
 133 metarules. Higher levels cause expanded metarules to be included.
 134 Level 0 does not add comments at all.
 135
 136 =back
 137
 138 =head1 BUGS
 139
 140 A value can not have whitespace in it.
 141
 142 =head1 EXAMPLE
 143
 144 (this does not look good, formatted)
 145
 146 I<ipf.objs>
 147
 148 [PRIVATE] 10.0.0.0/8 127.0.0.0/8 172.16.0.0/12 192.168.0.0/16
 149
 150 [MULTICAST] 224.0.0.0/4
 151
 152 [UNWANTED] PRIVATE MULTICAST
 153
 154 [NOC] xxx.yy.zz.1/32 xxx.yy.zz.2/32
 155
 156 [WEBSERVERS] 192.168.1.1/32 192.168.1.2/32
 157
 158 [MGMT-PORTS] 22 23
 159
 160 I<ipf.metarules>
 161
 162 block in from UNWANTED to any
 163
 164 pass  in from NOC to WEBSERVERS port = MGMT-PORTS
 165
 166 pass  out all
 167
 168 I<Run>
 169
 170 ipfmeta ipf.objs <ipf.metarules >ipf.rules
 171
 172 I<Output>
 173
 174 # block in from UNWANTED to any
 175
 176 block in from 10.0.0.0/8 to any
 177
 178 block in from 127.0.0.0/8 to any
 179
 180 block in from 172.16.0.0/12 to any
 181
 182 block in from 192.168.0.0/16 to any
 183
 184 block in from 224.0.0.0/4 to any
 185
 186 # pass  in from NOC to WEBSERVERS port = MGMT-PORTS
 187
 188 pass  in from xxx.yy.zz.1/32 to 192.168.1.1/32 port = 22
 189
 190 pass  in from xxx.yy.zz.1/32 to 192.168.1.1/32 port = 23
 191
 192 pass  in from xxx.yy.zz.1/32 to 192.168.1.2/32 port = 22
 193
 194 pass  in from xxx.yy.zz.1/32 to 192.168.1.2/32 port = 23
 195
 196 pass  in from xxx.yy.zz.2/32 to 192.168.1.1/32 port = 22
 197
 198 pass  in from xxx.yy.zz.2/32 to 192.168.1.1/32 port = 23
 199
 200 pass  in from xxx.yy.zz.2/32 to 192.168.1.2/32 port = 22
 201
 202 pass  in from xxx.yy.zz.2/32 to 192.168.1.2/32 port = 23
 203
 204 pass  out all
 205
 206 =head1 AUTHOR
 207
 208 Camiel Dobbelaar <cd@sentia.nl>. B<ipfmeta> is in the Public Domain.
 209
 210 =cut