#! /usr/bin/perl -w

use strict;
use Getopt::Long;

my $domain = "";
my $wildcard = 0;

my $ok = GetOptions('d=s' => \$domain,
		    'w' => \$wildcard);

my $RESPDNS = "hostmaster\@domain.com";
my $TTLMIN  = 7200;
my @NS = qw(ns1.domain.com ns2.domain.com);

my $serial_no = serialnumber();

my $REFRESH = 21600;
my $RETRY   =  3600;
my $EXPIRE  = 216000;

write_soa($domain);

while (<>) {
  chomp;

  eff_blancs($_);

  if (/^\#/) {
    $_ =~ tr/\#/ /;
    #printf "; %s\n", $_;
    next;
  }
  next if /^\s*[#]*\s*$/;

  my ($host, $rem) = split " ", $_, 2;

  my @ENTRY = qw();
  if (is_ip_valid($host)) {
    push @ENTRY, rev_ip($host);
  } else {
    push @ENTRY, $host;
    push @ENTRY, "*." . $host if $wildcard;
  }

  eff_blancs($rem) if defined $rem;

  foreach my $x (@ENTRY) {
    printf "%-40s   IN      TXT  \"$rem\"\n", $x, $rem if defined($rem) && $rem ne "";
    printf "%-40s   IN      A    127.0.0.2\n", $x;
  }
}

exit 0;

######################################################################
#
# Ecrit l'enregistrement SOA
#
sub write_soa {
  return unless ($#_ >= 0);
  my ($domain, undef) = @_;

  my $respdns = $RESPDNS;
  $respdns =~ tr/\@/\./;

  my $date = `date`;
  chomp($date);

  print <<H1;
;
; Ecole des Mines de Paris - Centre de Calcul
;
; Scripts de Generation du DNS
;   Auteur : Jose Marcio Martins da Cruz
;
; Fichier genere le $date
;
;
;\$ORIGIN    .
\$TTL       $TTLMIN
; --------------------------------------------------------------
\@ IN SOA $NS[0]. $respdns. (
                $serial_no      ; Serial Number
                $REFRESH           ; Refresh
                $RETRY          ; Retry
                $EXPIRE         ; Expire
                $TTLMIN)         ; Minimum
;
; ---------------------------------------------------------------
;
H1

  foreach (@NS) {
    print <<H2;
      $TTLMIN      NS               $_.
H2
  }

  # define here static things which can't be generated by this script
  print <<H3;
;
;                   IN      A        1.2.3.4
;
\$ORIGIN $domain.
;
H3
}

######################################################################
#
# Supprime les blans en debut et fin d::une chaine de caracteres
#
sub eff_blancs {
  my ($p, undef) = @_;
  return "" if ! defined($p);
  $p =~ s/^[ \t]+|[ \t]+$//g;
  return $p;
}


######################################################################
#
#
sub is_ip_valid {
  my ($ip, undef) = @_;

  return 0 if !defined($ip);

  my ($i, @j);

  return 0 if ($ip =~ /[^0-9\.]/);
  @j = split('\.',$ip);
  return 0 if $#j > 3;
  foreach $i (@j) {
    return 0 if (!defined($i) || (length($i) <= 0) || ($i < 0) || ($i > 255));
  }
  return 1;
}


######################################################################
#
# Inverse une adresse IP
#
sub rev_ip {
  my ($net, undef) = @_;
  return "XXXXXX" if !defined($net);
  my @IP = split('\.',$net);

  return "XXXXXX" if $#IP < 0;

  if ($#IP < 3) {
    push(@IP, "*");
  }
  return join('.',reverse(@IP));
}

sub serialnumber {
  return sprintf "%d", time();
}