From 03b1ea766aa5821ebc18eee86506317bd91a7d32 Mon Sep 17 00:00:00 2001
From: Dylan T <odigiman@gmail.com>
Date: Fri, 4 Dec 2020 21:21:25 +0000
Subject: [PATCH] Added a DedicatedQueryNetworkInterface to ensure Query
 functionality when RakLibInterface is disabled (#3942)

---
 src/Server.php                                |  10 +-
 .../query/DedicatedQueryNetworkInterface.php  | 163 ++++++++++++++++++
 2 files changed, 171 insertions(+), 2 deletions(-)
 create mode 100644 src/network/query/DedicatedQueryNetworkInterface.php

diff --git a/src/Server.php b/src/Server.php
index 0e2084762..c1be895c9 100644
--- a/src/Server.php
+++ b/src/Server.php
@@ -60,6 +60,7 @@ use pocketmine\network\mcpe\raklib\RakLibInterface;
 use pocketmine\network\Network;
 use pocketmine\network\query\QueryHandler;
 use pocketmine\network\query\QueryInfo;
+use pocketmine\network\query\DedicatedQueryNetworkInterface;
 use pocketmine\network\upnp\UPnP;
 use pocketmine\permission\BanList;
 use pocketmine\permission\DefaultPermissions;
@@ -1037,10 +1038,15 @@ class Server{
 
 			$this->enablePlugins(PluginEnableOrder::POSTWORLD());
 
-			$this->network->registerInterface(new RakLibInterface($this));
+			$useQuery = $this->configGroup->getConfigBool("enable-query", true);
+			if(!$this->network->registerInterface(new RakLibInterface($this)) && $useQuery){
+				//RakLib would normally handle the transport for Query packets
+				//if it's not registered we need to make sure Query still works
+				$this->network->registerInterface(new DedicatedQueryNetworkInterface($this->getIp(), $this->getPort(), new \PrefixedLogger($this->logger, "Dedicated Query Interface")));
+			}
 			$this->logger->info($this->getLanguage()->translateString("pocketmine.server.networkStart", [$this->getIp(), $this->getPort()]));
 
-			if($this->configGroup->getConfigBool("enable-query", true)){
+			if($useQuery){
 				$this->network->registerRawPacketHandler(new QueryHandler($this));
 			}
 
diff --git a/src/network/query/DedicatedQueryNetworkInterface.php b/src/network/query/DedicatedQueryNetworkInterface.php
new file mode 100644
index 000000000..5a083a9e3
--- /dev/null
+++ b/src/network/query/DedicatedQueryNetworkInterface.php
@@ -0,0 +1,163 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\network\query;
+
+use pocketmine\network\AdvancedNetworkInterface;
+use pocketmine\network\Network;
+use function preg_match;
+use function socket_bind;
+use function socket_close;
+use function socket_create;
+use function socket_last_error;
+use function socket_recvfrom;
+use function socket_select;
+use function socket_sendto;
+use function socket_strerror;
+use function trim;
+use const AF_INET;
+use const PHP_INT_MAX;
+use const SOCK_DGRAM;
+use const SOCKET_EADDRINUSE;
+use const SOCKET_ECONNRESET;
+use const SOCKET_EWOULDBLOCK;
+use const SOL_UDP;
+
+/**
+ * This is a supplementary network interface to maintain Query functionality when the RakLibInterface is not registered.
+ *
+ * Normally, Query runs on the same port as RakLib does, so Query handles packets coming in on RakLib's socket instead
+ * of using its own interface.
+ *
+ * However, it's necessary to have a separate interface for the cases where the RakLib interface is either not registered
+ * or running on a different port than Query.
+ */
+final class DedicatedQueryNetworkInterface implements AdvancedNetworkInterface{
+
+	/** @var string */
+	private $ip;
+	/** @var int */
+	private $port;
+	/** @var \Logger */
+	private $logger;
+	/** @var resource */
+	private $socket;
+	/** @var Network */
+	private $network;
+	/**
+	 * @var int[] address => timeout time
+	 * @phpstan-var array<string, int>
+	 */
+	private $blockedIps = [];
+	/** @var string[] */
+	private $rawPacketPatterns = [];
+
+	public function __construct(string $ip, int $port, \Logger $logger){
+		$this->ip = $ip;
+		$this->port = $port;
+		$this->logger = $logger;
+
+		$socket = @socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
+		if($socket === false){
+			throw new \RuntimeException("Failed to create socket");
+		}
+		$this->socket = $socket;
+	}
+
+	public function start() : void{
+		if(!@socket_bind($this->socket, $this->ip, $this->port)){
+			$error = socket_last_error($this->socket);
+			if($error === SOCKET_EADDRINUSE){ //platform error messages aren't consistent
+				throw new \RuntimeException("Failed to bind socket: Something else is already running on $this->ip $this->port", $error);
+			}
+			throw new \RuntimeException("Failed to bind to $this->ip $this->port: " . trim(socket_strerror($error)), $error);
+		}
+		socket_set_nonblock($this->socket);
+		$this->logger->info("Running on $this->ip $this->port");
+	}
+
+	public function setName(string $name) : void{
+		//NOOP
+	}
+
+	public function tick() : void{
+		$r = [$this->socket];
+		$w = null;
+		$e = null;
+		if(@socket_select($r, $w, $e, 0, 0) === 1){
+			$address = "";
+			$port = 0;
+			$buffer = "";
+			while(true){
+				$bytes = @socket_recvfrom($this->socket, $buffer, 65535, 0, $address, $port);
+				if($bytes !== false){
+					if(isset($this->blockedIps[$address]) && $this->blockedIps[$address] > time()){
+						$this->logger->debug("Dropped packet from banned address $address");
+						continue;
+					}
+					foreach($this->rawPacketPatterns as $pattern){
+						if(preg_match($pattern, $buffer) === 1){
+							$this->network->processRawPacket($this, $address, $port, $buffer);
+							break;
+						}
+					}
+				}else{
+					$errno = socket_last_error($this->socket);
+					if($errno === SOCKET_EWOULDBLOCK){
+						break;
+					}
+					if($errno !== SOCKET_ECONNRESET){ //remote peer disappeared unexpectedly, this might spam like crazy so we don't log it
+						$this->logger->debug("Failed to recv (errno $errno): " . trim(socket_strerror($errno)));
+					}
+				}
+			}
+		}
+	}
+
+	public function blockAddress(string $address, int $timeout = 300) : void{
+		$this->blockedIps[$address] = $timeout > 0 ? time() + $timeout : PHP_INT_MAX;
+	}
+
+	public function unblockAddress(string $address) : void{
+		unset($this->blockedIps[$address]);
+	}
+
+	public function setNetwork(Network $network) : void{
+		$this->network = $network;
+	}
+
+	public function sendRawPacket(string $address, int $port, string $payload) : void{
+		if(@socket_sendto($this->socket, $payload, strlen($payload), 0, $address, $port) === false){
+			$errno = socket_last_error($this->socket);
+			throw new \RuntimeException("Failed to send to $address $port (errno $errno): " . trim(socket_strerror($errno)), $errno);
+		}
+	}
+
+	public function addRawPacketFilter(string $regex) : void{
+		$this->rawPacketPatterns[] = $regex;
+	}
+
+	public function shutdown() : void{
+		@socket_close($this->socket);
+	}
+}