Add ConnectionRequestEvent and implement it

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

@@ -0,0 +1,64 @@
+/*
+ * 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.geysermc.event.Cancellable;
+import org.geysermc.event.Event;
+
+/**
+ * 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 String ip;
+
+    public ConnectionRequestEvent(@NonNull String ip) {
+        this.ip = ip;
+    }
+
+    /**
+     * @return the IP address of the client attempting to connect.
+     */
+    @NonNull
+    public String getIp() {
+        return ip;
+    }
+
+    /**
+     * @return the cancel status of this event. If this event is cancelled, the connection will be rejected.
+     */
+    @Override
+    public boolean isCancelled() {
+        return cancelled;
+    }
+
+    @Override
+    public void setCancelled(boolean cancelled) {
+        this.cancelled = cancelled;
+    }
+}

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

@@ -48,6 +48,7 @@ import org.cloudburstmc.netty.channel.raknet.config.RakChannelOption;
 import org.cloudburstmc.netty.handler.codec.raknet.server.RakServerOfflineHandler;
 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;
@@ -233,6 +234,13 @@ public final class GeyserServer {
         } else {
             ip = "<IP address withheld>";
         }
+
+        ConnectionRequestEvent requestEvent = new ConnectionRequestEvent(ip);
+        geyser.eventBus().fire(requestEvent);
+        if (requestEvent.isCancelled()) {
+            return false;
+        }
+
         geyser.getLogger().info(GeyserLocale.getLocaleStringLog("geyser.network.attempt_connect", ip));
         return true;
     }