php-ddns-client.php

<?php

/*
 * This is a simple client for updating hosts at a Dynamic DNS service
 * provider.
 */

/*
 * Copyright (C) 2011 Michael Bemmerl
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* Start of configuration area */

$user = 'test';								// Your DDNS username
$pass = 'test';								// Your DDNS password

$hosts[] = 'test.mine.nu';					// The hosts you want to update
//$hosts[] = 'another-host.dyndns.org';

$force = FALSE;								// Set to TRUE if you want to force an update

/* End of configuration area */

function ddns_get_ipaddress()
{
	$content = @file_get_contents('http://checkip.dyndns.com');

	$matched = $content !== FALSE && (bool)preg_match('/\d*\.\d*\.\d*\.\d*/', $content, $matches);

	if ($matched)
		return $matches[0];
	else
		return FALSE;
}

function ddns_resolve_host($host)
{
	$ips = dns_get_record($host, DNS_A);

	if ($ips === FALSE)
		return FALSE;

	$result = array();

	foreach($ips as $ip)
		$result[] = $ip['ip'];

	return $result;
}

function ddns_update_host($host, $newIP)
{
	global $user, $pass;

	$url = sprintf('http://%s:%s@members.dyndns.org/nic/update?hostname=%s&myip=%s', $user, $pass, $host, $newIP);

	$opts = array('http' => array('user_agent' => 'php-ddns-client 0.1'));
	$context = stream_context_create($opts);

	$content = file_get_contents($url, false, $context);

	$matched = $content !== FALSE && (bool)preg_match('/^\w*/', $content, $matches);

	if ($matched === FALSE)
		return FALSE;

	$result = strtolower($matches[0]);

	return $result == 'good';
}

function ddns_error($message, $die = TRUE)
{
	header('HTTP/1.0 500 Internal Server Error');
	print $message;

	if ($die)
		die();
}

header('Content-Type: text/plain');

$currentIP = ddns_get_ipaddress();

if ($currentIP === FALSE)
	ddns_error('Could not detect external IP address.');

foreach($hosts as $host)
{
	print 'Updating \'' . $host . '\': ';

	if (!$force)
		$oldIPs = ddns_resolve_host($host);

	if ($force || !in_array($currentIP, $oldIPs, TRUE))
	{
		$result = ddns_update_host($host, $currentIP);

		print $result ? 'success' : 'failed!';
	}
	else
		print 'not neccessary';

	print PHP_EOL;
}