#!/usr/local/bin/perl -w

# This little script uses ddup to keep the dyndns record uptodate.
# It will only update if the IP has changed!
# It also needs an extra perl module called LWP::Simple.
# complaints to giggel@mugiri.de

use strict;
use LWP::Simple;

# configure me!
my $datafile = "/var/db/dynip.dat";
my $dynhost = "foo.dyndns.org";
my $dynhost2 = "bar.dyndns.org";
my $debug = 1;
my $content = get("http://checkip.dyndns.org");

# stop configuring here

if (defined($content)) {
	$content =~ /(\d+\.\d+\.\d+\.\d+)/;
	my $ip = $1;
	my $oldip = readip();
	writeip($ip);
	print "current IP is $ip\n" if ($debug);
	print "last recorded IP was $oldip\n" if ($debug);
	unless ($ip eq $oldip) {
		print "need to update\n" if ($debug);
#		print "ddup --host $dynhost --ip $ip --mx $dynhost --wildcard";
		`/usr/local/sbin/ddup --host $dynhost --ip $ip --mx $dynhost --wildcard`;
		print if ($debug);
#		print "ddup --host $dynhost2 --ip $ip --mx $dynhost2 --wildcard";
		`/usr/local/sbin/ddup --host $dynhost2 --ip $ip --mx $dynhost2 --wildcard`;
		print if ($debug);
	}
} else {
	print "bad\n";
}

sub readip {
	open(IN, "<".$datafile) || die "Can't open $datafile for reading: ".$!;
	my $ip = <IN>;
	close IN;
	return $ip;
}

sub writeip {
	my $ip = shift;
	open(OUT, ">".$datafile) || die "Can't open $datafile for writing: ".$!;
	print OUT $ip;
	close OUT;
}