<?php
/* Copyright 2010 Ivo Smits <Ivo@UCIS.nl>. All rights reserved.
   Redistribution and use in source and binary forms, with or without modification, are
   permitted provided that the following conditions are met:

   1. Redistributions of source code must retain the above copyright notice, this list of
      conditions and the following disclaimer.

   2. Redistributions in binary form must reproduce the above copyright notice, this list
      of conditions and the following disclaimer in the documentation and/or other materials
      provided with the distribution.

   THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
   ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

   The views and conclusions contained in the software and documentation are those of the
   authors and should not be interpreted as representing official policies, either expressed
   or implied, of Ivo Smits.*/

if (defined('APP_LOADED')) return;
define('APP_LOADED', TRUE);
if (!defined('CONFIGFILE')) define('CONFIGFILE', './config.php');

print("UCIS UDPMSG3 Hub (c) 2010 Ivo Smits <Ivo@UCIS.nl>\n");
print("More information: http://wiki.ucis.nl/UDPMSG3\n");
print("\n");

class StreamPeer {
	public $socket = NULL;
	public $buffer = '';
	public function select_read() {
		if ($this->udpmsg_read()) return;
		socket_delete($this);
		socket_close($this->socket);
		fprintf(STDERR, "UDPMSG: Error: closing connection.\n");
		peer_delete($this);
		$this->closed();
	}
	public function select_error() {
		socket_delete($this);
		socket_close($this->socket);
		fprintf(STDERR, "UDPMSG: Error: select error.\n");
		peer_delete($this);
		$this->closed();
	}
	private function udpmsg_read() {
		$msg = socket_read($this->socket, 1024);
		if (!strlen($msg)) {
			fprintf(STDERR, "UDPMSG: End of file\n");
			return FALSE;
		}
		$udpmsg_buffer = &$this->buffer;
		$udpmsg_buffer .= $msg;
		while (strlen($udpmsg_buffer) > 2) {
			$len = ord($udpmsg_buffer[0]) * 256 + ord($udpmsg_buffer[1]);
			if ($len <= 0 || $len > 1024) {
				fprintf(STDERR, "UDPMSG: Error: protocol error\n");
				return FALSE;
			}
			if (strlen($udpmsg_buffer) < 2 + $len) break;
			udpmsg_receive($this, substr($udpmsg_buffer, 2, $len));
			$udpmsg_buffer = substr($udpmsg_buffer, 2 + $len);
		}
		return TRUE;
	}
	public function send($msg) {
		$len = strlen($msg);
		if ($len > 1024) {
			fprintf(STDERR, "UDPMSG: Error: message too long!\n");
			return FALSE;
		}
		$lens = chr(floor($len / 256)).chr($len % 256);
		socket_write($this->socket, $lens.$msg);
		return TRUE;
	}
}
class StreamServer {
	public $host, $port, $bindhost, $bindport, $ipv6;
	public $socket = NULL;
	function __construct($host, $port, $ipv6 = FALSE) {
		$this->host = $host; $this->port = $port; $this->ipv6 = $ipv6;
		if (!$this->select_timeout()) socket_add_timeout($this);
	}
	public function select_timeout() {
		socket_delete($this);
		$this->socket = socket_create($this->ipv6 ? AF_INET6 : AF_INET, SOCK_STREAM, SOL_TCP);
		socket_set_nonblock($this->socket);
		socket_set_option($this->socket, SOL_SOCKET, SO_REUSEADDR, 1);
		if (!socket_bind($this->socket, $this->host, $this->port)) return FALSE;
		if (!socket_listen($this->socket)) return FALSE;
		socket_delete($this);
		socket_add_connected($this);
		return TRUE;
	}
	public function select_read() {
		$client = socket_accept($this->socket);
		if (!$client) return;
		if (!socket_getpeername($client, &$addr, &$port)) $addr = 'unknown';
		fprintf(STDERR, 'UDPMSG: Accepted client '.$addr.':'.$port."\n");
		new StreamServerClient($client);
	}
	public function select_error() {
		socket_close($this->socket);
		fprintf(STDERR, "UDPMSG: Error: select error on listener. Closing listener.\n");
		socket_delete($this);
		socket_add_timeout($this);
	}
}
class StreamClient extends StreamPeer {
	public $host, $port, $bindhost, $bindport, $ipv6;
	function __construct($host, $port, $ipv6 = FALSE, $bindhost = NULL, $bindport = NULL) {
		$this->host = $host; $this->port = $port; $this->ipv6 = $ipv6; $this->bindhost = $bindhost; $this->bindport = $bindport;
		$this->select_timeout();
	}
	public function closed() {
		socket_add_timeout($this);
	}
	public function select_timeout() {
		socket_delete($this);
		$this->socket = socket_create($this->ipv6 ? AF_INET6 : AF_INET, SOCK_STREAM, SOL_TCP);
		socket_set_nonblock($this->socket);
		if ($this->bindhost || $this->bindport) socket_bind($this->socket, $this->bindhost, $this->bindport);
		socket_connect($this->socket, $this->host, $this->port);
		socket_add_connecting($this);
	}
	public function select_write() {
		if (!socket_getpeername($this->socket, &$addr, &$port)) $addr = 'unknown';
		fprintf(STDERR, 'UDPMSG: Connected to '.$addr.':'.$port."\n");
		socket_delete($this);
		socket_add_connected($this);
		peer_add($this);
	}
}
class StreamServerClient extends StreamPeer {
	public function closed() { }
	function __construct($socket) {
		socket_set_nonblock($socket);
		$this->socket = $socket;
		socket_add_connected($this);
		peer_add($this);
	}
}
class UDPPeer {
	public $socket = NULL;
	function __construct($host = NULL, $port = NULL, $ipv6 = FALSE, $bindhost = NULL, $bindport = NULL) {
		$this->socket = socket_create($ipv6 ? AF_INET6 : AF_INET, SOCK_DGRAM, SOL_UDP);
		socket_set_nonblock($this->socket);
		if ($bindhost || $bindport) socket_bind($this->socket, $bindhost, $bindport);
		socket_add_connected($this);
		if ($host) {
			socket_connect($this->socket, $host, $port);
			peer_add($this);
		}
	}
	public function select_read() {
		if ($this->udpmsg_read()) return;
		fprintf(STDERR, "UDPMSG: Error: closing connection.\n");
	}
	public function select_error() {
		fprintf(STDERR, "UDPMSG: Error: select error.\n");
	}
	private function udpmsg_read() {
		$msg = socket_read($this->socket, 1024 + 20);
		//$msg = '';
		//if (socket_recvfrom($this->socket, $msg, 1024 + 20, 0, $name, $port) <= 0) return FALSE;
		if (!strlen($msg)) {
			fprintf(STDERR, "UDPMSG: End of file\n");
			return FALSE;
		}
		if (strlen($msg) < 20 || substr($msg, 0, 20) != sha1(substr($msg, 20), TRUE)) {
			fprintf(STDERR, "UDPMSG: Short message or checksum mismatch\n");
			return FALSE;
		}
		udpmsg_receive($this, substr($msg, 20));
		return TRUE;
	}
	public function send($msg) {
		socket_write($this->socket, sha1($msg, TRUE).$msg);
		return TRUE;
	}
}

$msgi = 0;
$msglog = array();

$sock_fd_connecting = array();
$sock_fd_connected = array();
$sock_timeout = array();
$sock_obj = array();

$peers = array();

function peer_add($obj) {
	global $peers;
	$peers[spl_object_hash($obj)] = $obj;
}
function peer_delete($obj) {
	global $peers;
	unset($peers[spl_object_hash($obj)]);
}

function socket_add_timeout($obj) {
	global $sock_timeout;
	$sock_timeout[spl_object_hash($obj)] = $obj;
}
function socket_add_connecting($obj) {
	global $sock_fd_connecting, $sock_obj;
	$sock_fd_connecting[(int)$obj->socket] = $obj->socket;
	$sock_obj[(int)$obj->socket] = $obj;
}
function socket_add_connected($obj) {
	global $sock_fd_connected, $sock_obj;
	$sock_fd_connected[(int)$obj->socket] = $obj->socket;
	$sock_obj[(int)$obj->socket] = $obj;
}
function socket_delete($obj) {
	global $sock_fd_connecting, $sock_fd_connected, $sock_obj, $sock_timeout;
	unset($sock_fd_connecting[(int)$obj->socket]);
	unset($sock_fd_connected[(int)$obj->socket]);
	unset($sock_obj[(int)$obj->socket]);
	unset($sock_timeout[spl_object_hash($obj)]);
}

print("Loading configuration...\n");
if (!isset($config)) require constant('CONFIGFILE');

$logsize = isset($config['logsize'])?$config['logsize']:512;
if (isset($config['tcplisten']))
	foreach ($config['tcplisten'] as $e)
		new StreamServer(
			isset($e['host']) ? $e['host'] : '0.0.0.0',
			isset($e['port']) ? $e['port'] : 15387,
			isset($e['ipv6']) && $e['ipv6']);
if (isset($config['tcpconnect']))
	foreach ($config['tcpconnect'] as $e)
		new StreamClient(
			isset($e['host']) ? $e['host'] : '127.0.0.1',
			isset($e['port']) ? $e['port'] : 15387,
			isset($e['ipv6']) && $e['ipv6'],
			isset($e['bindhost']) ? $e['bindhost'] : NULL,
			isset($e['bindport']) ? $e['bindport'] : NULL);
if (isset($config['udppeer']))
	foreach ($config['udppeer'] as $e)
		new UDPPeer(
			isset($e['host']) ? $e['host'] : NULL,
			isset($e['port']) ? $e['port'] : 15387,
			isset($e['ipv6']) && $e['ipv6'],
			isset($e['bindhost']) ? $e['bindhost'] : NULL,
			isset($e['bindport']) ? $e['bindport'] : NULL);

function udpmsg_receive($from, $msg) {
	global $peers, $msgi, $msglog, $logsize;
	$hash = md5($msg);
	if (in_array($hash, $msglog)) return FALSE;
	$msglog[$msgi] = $hash;
	$msgi++;
	if ($msgi >= $logsize) $msgi = 0;
	$count = 0;
	foreach ($peers as $peer) if ($peer !== $from) if ($peer->send($msg)) $count++;
	return $count;
}

while (TRUE) {
	$selread = $sock_fd_connected;
	$selwrite = $sock_fd_connecting;
	$selerror = array_merge($selread, $selwrite);
	if (count($selerror)) {
		socket_select(&$selread, &$selwrite, &$selerror, 60);
		foreach ($selread as $socket) if (isset($sock_obj[(int)$socket])) $sock_obj[(int)$socket]->select_read($socket);
		foreach ($selwrite as $socket) if (isset($sock_obj[(int)$socket])) $sock_obj[(int)$socket]->select_write($socket);
		foreach ($selerror as $socket) if (isset($sock_obj[(int)$socket])) $sock_obj[(int)$socket]->select_error($socket);
	} else {
		sleep(10);
	}
	foreach ($sock_timeout as $obj) $obj->select_timeout();
}