UDPProxy.php

<?php
class UDPProxy extends \Threaded {

	// private static $ENCRYPT_KEY = 'jsd8hv8QWCH';

	/**@var stream*/
	public $socket;

	/**@var stream*/
	public $sql;

	/**@var array*/
	public $clients = [];

	/**@var array*/
	public $threads = [];

	/**@var array*/
	public $lastPacket = [];

	/**@var bool*/
	public $shouldStop = false;

	/**@var int*/
	public $threadCount = 5;

	public function __construct(string $address, int $port, string $db_address, string $db_user, string $db_password, string $db_name, int $threadCount = 5, int $timeout = 2) {
		$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);

		if(@socket_bind($socket, $address, $port)) {
			socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 0);

			@socket_set_option($socket, SOL_SOCKET, SO_SNDBUF, 1024 * 1024 * 8);
			@socket_set_option($socket, SOL_SOCKET, SO_RCVBUF, 1024 * 1024 * 8);

			/*$sql = mysqli_connect('p' . $db_address, $db_user, $db_password, $db_name);
			if(!$sql) {
				echo mysqli_connect_error($sql) . PHP_EOL;
				exit;
			}*/

			@socket_set_nonblock($socket);
			@socket_set_timeout($socket, $timeout);

			// $this->sql = $sql;
			$this->socket = $socket;
			$this->threadCount = $threadCount;

			for($i = 0; $i < $threadCount; $i++) {
				$this->threads[$i] = (new UDPThread($this, $i));
			}
		}
		else {
			echo trim(socket_strerror(socket_last_error($socket))) . PHP_EOL;
			exit;
		}
	}

	public function start() {
		foreach($this->threads as $contents) {
			$contents->start();
		}
	}

	public function process() {
		if(!$this->shouldStop) {
			socket_recvfrom($this->socket, $buffer, 65536, 0, $address, $port);

			if(is_null($buffer)) {
				return;
			}

			$identifier = hash('sha1', strval($address . $port));

			if(!isset($this->clients[$identifier])) {
				$contents = new \Threaded;

				$threadIndex = null;
				while(!isset($this->threads[$threadIndex])) {
					$threadIndex = mt_rand(0, $this->threadCount);
				}

				$contents->client_addr = $address;
				$contents->client_port = $port;
				$contents->client_socket = socket_create(AF_INET, SOCK_DGRAM, 0);
				$contents->forward_addr = '66.70.171.222'; // play.cosmicpe.me
				$contents->forward_port = 19132;
				$contents->last_packet = time();
				$contents->thread_index = $threadIndex;
				// $contents['send_server_queue'] = [];
				// $contents['send_client_queue'] = [];

				$socket = $contents->client_socket;
				socket_sendto($socket, $buffer, strlen($buffer), 0, $contents->forward_addr, $contents->forward_port);

				$this->clients[$identifier] = $contents;

				$this->threads[$threadIndex]->addClient($identifier, $contents);

				echo "Adding client for ('{$address}', {$port})" . PHP_EOL;
			}
 			else {
				$client = $this->clients[$identifier];
				$this->lastPacket[$identifier] = time();

				socket_sendto($client->client_socket, $buffer, strlen($buffer), 0, $client->forward_addr, $client->forward_port);
			}
		}
		else {
			exit; // todo: handle shutdown better
		}
	}
}
class UDPThread extends \Thread {

	/**@var UDPProxy*/
	private $proxy;

	/**@var int*/
	private $threadIndex;

	/**@var array*/
	private $clients = [];

	public function __construct(UDPProxy $proxy, int $threadIndex) {
		$this->proxy = $proxy;
		$this->threadIndex = $threadIndex;
	}

	public function addClient(string $identifier, \Threaded $contents) {
		$this->clients[$identifier] = $contents;
	}

	public function run() {
		while(!$this->proxy->shouldStop) {
			foreach($this->clients as $identifier => $contents) {
				if($this->proxy->lastPacket[$identifier] - strtotime('-5 seconds') > 5) {
					unset($this->clients[$identifier]);
					unset($this->proxy->clients[$identifier]);
					continue;
				}

				socket_recvfrom($contents->client_socket, $buffer, 65536, 0, $server_address, $server_port);
				if(is_null($buffer)) {
					continue;
				}

				if($server_address !== $contents->forward_addr or $server_port !== $contents->forward_port) {
					continue;
				}

				socket_sendto($this->proxy->socket, $buffer, strlen($buffer), 0, $contents->client_addr, $contents->client_port);
			}
		}
	}
}

$proxy = new UDPProxy('0.0.0.0', 26625, "", "", "", "");
$proxy->start();

while(true) {
	$proxy->process();
}