#!/usr/local/bin/php
<?php

/* di-ip.php by David Sklar <tech-php at sklar.com>
 *
 * This program retrieves the WAN IP address that a DLink DI-704(P) 
 * router is assigned. It logs in to the router if necessary. 
 *
 * Once the program logs into the router, then any access from the IP
 * address that the program logs in from is permitted, so take care
 * not to run this program on a system where other users could make
 * malicious requests to your router.
 *
 * This program requires PHP 4 with the cURL extension.
 */

/*
 *  CONFIGURATION 
 */

/* Set $router_ip to the hostname or IP address of your DI704.
 * e.g. 192.168.0.1 */
$router_ip = '192.168.0.1';
/* Set $router_password to the administrative password of your DI704.
 * Anyone who can read this script can read the password, so be careful
 * with your permissions. */
$router_password = 'password';


/*********************************************************************/

if (! function_exists('curl_init')) {
    die("This program requires the cURL extension.");
}

/* Get the login form */
$c = curl_init("http://$router_ip/menu.htm?RC=@");
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
$login_page = curl_exec($c);
curl_close($c);

/* If we're not already logged in, log in */
if (! preg_match("/Administrator's Main Menu/",$login_page)) {
    // parse variables out of login page
    preg_match_all('/<INPUT TYPE=HIDDEN VALUE="([^"]+?)" NAME=([^>]+?)>/',
                   $login_page, $matches, PREG_SET_ORDER);    
    
    $post_fields = array();
    foreach ($matches as $match) {
        $post_fields[] = urlencode($match[2]) . '=' . urlencode($match[1]);
        /* The password (in the URL field) has to go right after the PSWD
         * field for login to succeed */
        if ($match[2] == 'PSWD') {
            $post_fields[] = 'URL='.urlencode($router_password);
        }
    }
    
    $c = curl_init("http://$router_ip/cgi-bin/logi");
    curl_setopt($c, CURLOPT_POST, 1);
    curl_setopt($c, CURLOPT_POSTFIELDS, implode('&',$post_fields));
    curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
    $admin_page = curl_exec($c);
    curl_close($c);

    if (! preg_match("/Administrator's Main Menu/",$admin_page)) {
        die("Can't login");
    }
}

/* Get the Status page */
$c = curl_init("http://$router_ip/status.htm");
curl_setopt($c, CURLOPT_RETURNTRANSFER, 1);
$status_page = curl_exec($c);
curl_close($c);

/* Look for the IP address */
if (preg_match('{<TD BGCOLOR=#006693 WIDTH=35%><font color=#ffffff>IP Address</font></TD><TD ALIGN=CENTER WIDTH=40%>([0-9\.]+)</TD>}',$status_page,$matches)) {
    print $matches[1];
} else {
    die("Can't get IP Address");
}

?>