#!/usr/bin/perl
# Name: Messy Create Reverse DNS Script
# Description: Takes all forward dns records and attempts to make reverse dns records
# Version: 1.0
# Authors: Jason Jorgensen <jasonj@innominatus.com>
# Copyright (C) 2003  Jason Jorgensen
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
###########################################################################

#Assumes master forward and records are in subdirectories from the script

$forwardpath = "master/";
$reversepath = "reverse/";


my $debug = 0;
my $line;
my %addrs;
my @inarpa;
my $inarpa;


opendir FORWARDFILES, "$forwardpath";
  my @forwardfiles = grep /^db\./, readdir FORWARDFILES;
  foreach $file (@forwardfiles) {
  my $headerstate = 2;
  my @header;
  my $domain;
  my $host;
  my $name;
  my $fullip;

    print "Opening file '$forwardpath$file'\n";
    open FORWARD, "<$forwardpath$file" || die "Cant open file '$file'";
    while (<FORWARD>) {
      $line = $_;
      chomp $line;
      print "DEBUG: line: $line\n" if $debug;
      if ($line =~ /;DEFAULTDOMAIN/) { (undef, $domain) = split /\s+/, $line; chomp $domain; }
      if ($line =~ /;HEADEREND/) { $headerstate = 0; }
      if ($headerstate == 1) { push @header, $line."\n"; }
      if ($line =~ /;HEADERSTART/) { $headerstate = 1; }
      if ($line =~ /^(\w+)\s+IN\s+A\s+(\d+\.\d+\.\d+\.\d+)$/) { 
        $name = $1;
        $fullip = $2;
        ($inarpa[2],$inarpa[1],$inarpa[0], $host) = split /\./, $2;
        $inarpa =  join '.', @inarpa;
        print "DEBUG: \$addrs{$inarpa}{$1} = $host\n" if $debug;
        if ($addrs{$inarpa}{$host}) { 
          $inarpa =~ /(\d+)\.(\d+)\.(\d+)/;
          my $subnet = "$3.$2.$1";
          print "Error, duplicate IP, resolution confliction: '$fullip-$name' overwriting '$subnet.$host-".$addrs{$inarpa}{$host}."\n";
        }
        if ($name =~ /.*\..*\.\s+$/) { $addrs{$inarpa}{$host} = $name; }
        elsif ($name =~ /\.\s+$/) { $addrs{$inarpa}{$host} = "$name."; }
        else { $addrs{$inarpa}{$host} = "$name.$domain."; }
      }
    $addrs{$inarpa}{header} = join '', @header;
    }
    if (! $domain) { print "Never saw domain name, make sure you specify ';DEFAULTDOMAIN example.com'\n"; next; }
    if ($headerstate == 2) { print "Never saw start of header, make sure you start your header with ';HEADERSTART'"; next; }
    if ($headerstate == 1) { print "Never saw end of header, make sure you end your header with ';HEADEREND'"; next; }
    #$addrs{$inarpa}{domain} .= " $domain";
  close FORWARD;
  }
closedir FORWARDFILES;
  
  
print "DEBUG: domain: $domain\n" if $debug;
  
foreach $inarpa (sort keys(%addrs)) { 
  if ($inarpa =~ /(\d+)\.(\d+)\.(\d+)/) {
    my $subnet = "$3.$2.$1";
    open REVERSE, ">".$reversepath."db.$inarpa";
    print REVERSE ";Reverse DNS for $subnet\n";
    print REVERSE $addrs{$inarpa}{header};
    print REVERSE ";HOSTS\n";
      foreach $addr (sort numerical keys(%{$addrs{$inarpa}})) {
        if ($addr =~ /\d+/) {
          print REVERSE "$addr\t\tIN\tPTR\t".$addrs{$inarpa}{$addr}."\n";
        }
      }
    close REVERSE;
  }
}


exit;


sub numerical { $a <=> $b; }