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#!/usr/local/bin/perl -w
# $Id: axfr 264 2005-04-06 09:16:15Z olaf $
use strict;
use vars qw($opt_f $opt_q $opt_s $opt_D);
use File::Basename;
use Getopt::Std;
use Net::DNS;
use Storable;
#------------------------------------------------------------------------------
# Read any command-line options and check syntax.
#------------------------------------------------------------------------------
getopts("fqsD:");
die "Usage: ", basename($0), " [ -fqs ] [ -D directory ] [ \@nameserver ] zone\n"
        unless (@ARGV >= 1) && (@ARGV <= 2);
#------------------------------------------------------------------------------
# Get the nameserver (if specified) and set up the zone transfer directory
# hierarchy.
#------------------------------------------------------------------------------
my $nameserver = ($ARGV[0] =~ /^@/) ? shift @ARGV : "";
$nameserver =~ s/^@//;
my $zone = shift @ARGV;
my $basedir = defined $opt_D ? $opt_D : $ENV{"HOME"} . "/.dns-zones";
my $zonedir = join("/", reverse(split(/\./, $zone)));
my $zonefile = $basedir . "/" . $zonedir . "/axfr";
# Don't worry about the 0777 permissions here - the current umask setting
# will be applied.
unless (-d $basedir) {
        mkdir($basedir, 0777) or die "can't mkdir $basedir: $!\n";
}
my $dir = $basedir;
my $subdir;
foreach $subdir (split(m#/#, $zonedir)) {
        $dir .= "/" . $subdir;
        unless (-d $dir) {
                mkdir($dir, 0777) or die "can't mkdir $dir: $!\n";
        }
}
#------------------------------------------------------------------------------
# Get the zone.
#------------------------------------------------------------------------------
my $res = Net::DNS::Resolver->new;
$res->nameservers($nameserver) if $nameserver;
my (@zone, $zoneref);
if (-e $zonefile && !defined $opt_f) {
        $zoneref = retrieve($zonefile) || die "couldn't retrieve zone from $zonefile: $!\n";
        #----------------------------------------------------------------------
        # Check the SOA serial number if desired.
        #----------------------------------------------------------------------
        if (defined $opt_s) {
                my($serial_file, $serial_zone);
                my $rr;
                foreach $rr (@$zoneref) {
                        if ($rr->type eq "SOA") {
                                $serial_file = $rr->serial;
                                last;
                        }
                }
                die "no SOA in $zonefile\n" unless defined $serial_file;
                my $soa = $res->query($zone, "SOA");
                die "couldn't get SOA for $zone: ", $res->errorstring, "\n"
                        unless defined $soa;
                foreach $rr ($soa->answer) {
                        if ($rr->type eq "SOA") {
                                $serial_zone = $rr->serial;
                                last;
                        }
                }
                if ($serial_zone != $serial_file) {
                        $opt_f = 1;
                }
        }
} else {
        $opt_f = 1;
}
if (defined $opt_f) {
        @zone = $res->axfr($zone);
        die "couldn't transfer zone: ", $res->errorstring, "\n" unless @zone;
        store \@zone, $zonefile or die "couldn't store zone to $zonefile: $!\n";
        $zoneref = \@zone;
}
#------------------------------------------------------------------------------
# Print the records in the zone.
#------------------------------------------------------------------------------
unless ($opt_q) {
        $_->print for @$zoneref
}
__END__
HideShow 73 lines of Pod
=head1 NAME
axfr - Perform a DNS zone transfer
=head1 SYNOPSIS
B<axfr> S<[ B<-fqs> ]> S<[ B<-D> I<directory> ]> S<[ B<@>I<nameserver> ]>
I<zone>
=head1 DESCRIPTION
B<axfr> performs a DNS zone transfer, prints each record to the standard
output, and stores the zone to a file.  If the zone has already been
stored in a file, B<axfr> will read the file instead of performing a
zone transfer.
Zones will be stored in a directory hierarchy.  For example, the
zone transfer for foo.bar.com will be stored in the file
$HOME/.dns-zones/com/bar/foo/axfr.  The directory can be changed
with the B<-D> option.
This programs requires that the Storable module be installed.
=head1 OPTIONS
=over 4
=item B<-f>
Force a zone transfer, even if the zone has already been stored
in a file.
=item B<-q>
Be quiet -- don't print the records from the zone.
=item B<-s>
Perform a zone transfer if the SOA serial number on the nameserver
is different than the serial number in the zone file.
=item B<-D> I<directory>
Store zone files under I<directory> instead of the default directory
(see L<"FILES">).
=item B<@>I<nameserver>
Query I<nameserver> instead of the default nameserver.
=back
=head1 FILES
=over 4
=item B<$HOME/.dns-zones>
Default directory for storing zone files.
=back
=head1 AUTHOR
Michael Fuhr <mike@fuhr.org>
=head1 SEE ALSO
L<perl(1)>, L<check_soa>, L<check_zone>, L<mresolv>, L<mx>, L<perldig>,
L<Net::DNS>, L<Storable>
=cut