Add ConnectionRequestEvent (#4533)

* Add ConnectionRequestEvent and implement it

* Add debug message and use InetSocketAddress instead of string

* Provide both proxy and real client ip

And add some minor javadocs

* Make ProxyIp nullable

* Apply changes from pr

Co-authored-by: rtm516 <rtm516@users.noreply.github.com>

* Apply changes from pr

Co-authored-by: rtm516 <rtm516@users.noreply.github.com>

* Apply changes from pr

Co-authored-by: rtm516 <rtm516@users.noreply.github.com>

* Bump API version

* Dont JiJ common on mod platforms

---------

Co-authored-by: rtm516 <rtm516@users.noreply.github.com>
Co-authored-by: Kas-tle <26531652+Kas-tle@users.noreply.github.com>

api/src/main/java/org/geysermc/geyser/api/event/connection/ConnectionRequestEvent.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2019-2024 GeyserMC. http://geysermc.org
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @author GeyserMC
+ * @link https://github.com/GeyserMC/Geyser
+ */
+
+package org.geysermc.geyser.api.event.connection;
+
+import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.geysermc.event.Cancellable;
+import org.geysermc.event.Event;
+
+import java.net.InetSocketAddress;
+
+/**
+ * Called whenever a client attempts to connect to the server, before the connection is accepted.
+ */
+public final class ConnectionRequestEvent implements Event, Cancellable {
+
+    private boolean cancelled;
+    private final InetSocketAddress ip;
+    private final InetSocketAddress proxyIp;
+
+    public ConnectionRequestEvent(@NonNull InetSocketAddress ip, @Nullable InetSocketAddress proxyIp) {
+        this.ip = ip;
+        this.proxyIp = proxyIp;
+    }
+
+    /**
+     * The IP address of the client attempting to connect
+     *
+     * @return the IP address of the client attempting to connect
+     */
+    @NonNull
+    public InetSocketAddress getInetSocketAddress() {
+        return ip;
+    }
+
+    /**
+     * The IP address of the proxy handling the connection. It will return null if there is no proxy.
+     *
+     * @return the IP address of the proxy handling the connection
+     */
+    @Nullable
+    public InetSocketAddress getProxyIp() {
+        return proxyIp;
+    }
+
+    /**
+     * The cancel status of this event. If this event is cancelled, the connection will be rejected.
+     *
+     * @return the cancel status of this event
+     */
+    @Override
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    /**
+     * Sets the cancel status of this event. If this event is canceled, the connection will be rejected.
+     *
+     * @param cancelled the cancel status of this event.
+     */
+    @Override
+    public void setCancelled(boolean cancelled) {
+        this.cancelled = cancelled;
+    }
+}

bootstrap/mod/fabric/build.gradle.kts

@@ -41,6 +41,7 @@ dependencies {
 
     // Let's shade in our own api
     shadow(projects.api) { isTransitive = false }
+    shadow(projects.common) { isTransitive = false }
 
     // Permissions
     modImplementation(libs.fabric.permissions)

bootstrap/mod/neoforge/build.gradle.kts

@@ -31,6 +31,7 @@ dependencies {
 
     // Let's shade in our own api
     shadow(projects.api) { isTransitive = false }
+    shadow(projects.common) { isTransitive = false }
 
     // Include all transitive deps of core via JiJ
     includeTransitive(projects.core)

core/src/main/java/org/geysermc/geyser/network/netty/GeyserServer.java

@@ -49,6 +49,7 @@ import org.cloudburstmc.netty.handler.codec.raknet.server.RakServerOfflineHandle
 import org.cloudburstmc.netty.handler.codec.raknet.server.RakServerRateLimiter;
 import org.cloudburstmc.protocol.bedrock.BedrockPong;
 import org.geysermc.geyser.GeyserImpl;
+import org.geysermc.geyser.api.event.connection.ConnectionRequestEvent;
 import org.geysermc.geyser.command.defaults.ConnectionTestCommand;
 import org.geysermc.geyser.configuration.GeyserConfiguration;
 import org.geysermc.geyser.event.type.GeyserBedrockPingEventImpl;
@@ -261,6 +262,14 @@ public final class GeyserServer {
         } else {
             ip = "<IP address withheld>";
         }
+
+        ConnectionRequestEvent requestEvent = new ConnectionRequestEvent(inetSocketAddress, this.proxiedAddresses.get(inetSocketAddress));
+        geyser.eventBus().fire(requestEvent);
+        if (requestEvent.isCancelled()) {
+            geyser.getLogger().debug("Connection request from " + ip + " was cancelled using the API!");
+            return false;
+        }
+
         geyser.getLogger().info(GeyserLocale.getLocaleStringLog("geyser.network.attempt_connect", ip));
         return true;
     }

gradle.properties

@@ -7,5 +7,5 @@ org.gradle.vfs.watch=false
 
 group=org.geysermc
 id=geyser
-version=2.2.2-SNAPSHOT
+version=2.2.3-SNAPSHOT
 description=Allows for players from Minecraft: Bedrock Edition to join Minecraft: Java Edition servers.