<?php
//The pattern used to validate hostnames
define(\"HOST_PATTERN\", \"#^(?:(?:(?:(?:[a-zA-Z0-9][-a-zA-Z0-9]{0,61})?[a-zA-Z0-9])[.])*(?:[a-zA-Z][-a-zA-Z0-9]{0,61}[a-zA-Z0-9]|[a-zA-Z])[.]?)$#\");

//Set this to true to enable ipv6 ping requests, false to disable.
define(\"IPV6_ENABLED\", true);

//Change this to make traceroutes faster when they fail (Currently 2 failed hops in a row stop it)
define(\"TRACEROUTE_LIMIT\", 2);

$function = trim($_REQUEST[\'function\']);
$query = trim($_REQUEST[\'query\']);
if(!preg_match(HOST_PATTERN, $query)) {
	$query = filter_var($query, FILTER_VALIDATE_IP);
	if(!$query) {
		die(\"invalid query\");
	}
	//Check for IPV6, hostnames unfortunately don\'t need it
	$temp = filter_var($query, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6);
	if($temp) {
		if(IPV6_ENABLED) {
			$function = $function == \'ping\' ? \'ping6\' : \'trace\';
		} else {
			die(\"Server does not process IPV6 requests\");
		}
	}
}
switch($function) {
	case \'ping\':
		echo shell_exec(\'ping -c 4 \' . escapeshellarg($query));
		break;
	case \'ping6\':
		echo shell_exec(\'ping6 -c 4 \' . escapeshellarg($query));
		break;
	case \'trace\':
		echo traceroute($query);
		break;
	default:
		echo \"Unknown method $function\\n\";
		break;
}

function traceroute($host) {
	$proc = popen(\'traceroute \' . escapeshellarg($host), \'r\');
	$out = array();
	$fails = 0;
	while($str = fgets($proc)) {
		if(preg_match(\"/\\s*\\d+\\s*\\*\\s*\\*\\s*\\*/\", $str)) {
			$fails++;
			if($fails >= TRACEROUTE_LIMIT) {
				//We want to get the hop AT the last failure, so we should be doing - 1
				$out[] = \"-- Route failure at \" . (count($out) - (TRACEROUTE_LIMIT - 1)) . \" hops --\";
				break;
			}
		}
		$out[] = trim($str);
	}
	pclose($proc);
	return implode(\"\\n\", $out);
}
?>