<?php
##
## this file name is 'class.ping.php'
##
## ping object
##
## [author]
##  - http://linuxchannel.net/
##
## [changes]
##  - 2008.12.01 : new build
##
## [references]
##  - http://kr.php.net/manual/en/function.socket-create.php
##
## [usage]
##
## [example]
##
class icmp
{
  // timeout in (seconds, microtime) 
  public function &ping($host, $timeout=array(0,500000))
  {
	static $port = 0;
	static $datasize = 58; // default 58 bytes + 8 = 64 bytes

	$ident = array(ord('J'), ord('C'));
	$seq = array(rand(0, 255), rand(0, 255));

	$timeout = array('sec'=>$timeout[0], 'usec'=>$timeout[1]);

	## 8 bytes of ICMP header data
	$packet = '';
	$packet .= chr(8); // type = 8 : request
	$packet .= chr(0); // code = 0
	$packet .= chr(0); // checksum init
	$packet .= chr(0); // checksum init
	$packet .= chr($ident[0]); // identifier
	$packet .= chr($ident[1]); // identifier
	$packet .= chr($seq[0]); // seq
	$packet .= chr($seq[1]); // seq

	for($i=0; $i<$datasize; $i++) $packet .= chr(0);

	$chk = icmp::icmpchecksum($packet);

	$packet[2] = $chk[0]; // checksum init
	$packet[3] = $chk[1]; // checksum init

	if(preg_match('/[a-z]/',$host)) $host = gethostbyname($host); // to ip

	if(!$sock = @socket_create(AF_INET, SOCK_RAW, getprotobyname('icmp')))
	{
		return array(-1, socket_last_error());
	}

	@socket_set_option($sock,SOL_SOCKET,SO_RCVTIMEO,$timeout); // good idea for blocking mode
	@socket_set_option($sock,SOL_SOCKET,SO_SNDTIMEO,$timeout);

	$time_start = microtime();
	@socket_sendto($sock, $packet, strlen($packet), 0, $host, $port);
	$time_send = microtime();

	$read   = array($sock);
	$write  = NULL;
	$except = NULL;
	$select = @socket_select($read, $write, $except, $timeout['sec'], $timeout['usec']);

	if($select === NULL)
	{
		@socket_close($sock);
		return array(-1, 'Select Error');
	}
	else if($select === 0)
	{
		@socket_close($sock);
		return array(-1, 'Timeout');
	}

	$recv = '';
	@socket_recvfrom($sock, $recv, 65535, 0, $host, $port);
	$time_stop = microtime();
	@socket_close($sock);

	$recv = unpack('C*', $recv);

	// ICMP proto = 1
	if($recv[10] !== 1) return array(-1,"Not ICMP packet");

	// ICMP response = 0
	if($recv[21] !== 0) return array(-1,"Not ICMP response");
	if($ident[0] !== $recv[25] || $ident[1] !== $recv[26]) return array(-1,"Bad identification number");
	if($seq[0] !== $recv[27] || $seq[1] !== $recv[28]) return array(-1,"Bad sequence number");

	$ttt = icmp::getms($time_start, $time_send);
	$gtt = icmp::getms($time_send, $time_stop);
	$rtt = icmp::getms($time_start, $time_stop);

	return array("$rtt $ttt $gtt",'');
  }

  private function &icmpchecksum($data)
  {
	$bit = unpack('n*', $data);
	$sum = array_sum($bit);

	if (strlen($data) % 2)
	{
		$temp = unpack('C*', $data[strlen($data) - 1]);
		$sum += $temp[1];
	}

	$sum = ($sum >> 16) + ($sum & 0xffff);
	$sum += ($sum >> 16);

	return pack('n*', ~$sum);
  }

  private function &getms($_start, $_end)
  {
	$end = explode(' ', $_end);
	$start = explode(' ', $_start);

	return sprintf('%.3f',(($end[1]+$end[0])-($start[1]+$start[0])) * 1000);
  }

  private function error($errstr)
  {
	return error_log($errstr,0);
  }

  private function &socket_info($socket)
  {
	$opt = array
	(
	'SO_DEBUG'=>SO_DEBUG,
	'SO_ACCEPTCONN'=>SO_ACCEPTCONN,
	'SO_BROADCAST'=>SO_BROADCAST,
	'SO_REUSEADDR'=>SO_REUSEADDR,
	'SO_KEEPALIVE'=>SO_KEEPALIVE,
	'SO_LINGER'=>SO_LINGER,
	'SO_OOBINLINE'=>SO_OOBINLINE,
	'SO_SNDBUF'=>SO_SNDBUF,
	'SO_RCVBUF'=>SO_RCVBUF,
	'SO_ERROR'=>SO_ERROR,
	'SO_TYPE'=>SO_TYPE,
	'SO_DONTROUTE'=>SO_DONTROUTE,
	'SO_RCVLOWAT'=>SO_RCVLOWAT,
	'SO_RCVTIMEO'=>SO_RCVTIMEO,
	'SO_SNDLOWAT'=>SO_SNDLOWAT,
	'SO_SNDTIMEO'=>SO_SNDTIMEO,
	);

	foreach ($opt as $k=>$value)
	{
		$r = socket_get_option($socket, SOL_SOCKET, $value);
		echo "$k : \n";
		print_r($r);
		echo "\n";
	}
  }
} // end of class
?>