Add anti-abuse banning mechanisms

src/main/java/com/lenis0012/bukkit/loginsecurity/LoginSecurityConfig.java

@@ -62,6 +62,19 @@ public class LoginSecurityConfig extends AbstractConfig {
     @ConfigKey(path = "join.hide-inventory-safe")
     private boolean hideInventory = false;
 
+    /**
+     * Ban settings.
+     */
+    @ConfigHeader("When enabled, automatically bans IPs trying to join as already logged in users")
+    @ConfigKey(path = "join.ban.simultaneous-login")
+    private boolean banSimultaneous = false;
+    @ConfigHeader("Notifies OPs in chat about LoginSecurity autobans")
+    @ConfigKey(path = "join.ban.notify-ops")
+    private boolean banNotifyOps = true;
+    @ConfigHeader("When enabled, automatically bans IPs which exceed 4 login tries")
+    @ConfigKey(path = "join.ban.bruteforce-attempt")
+    private boolean banBruteforceAttempt = false;
+
     /**
      * Username settings.
      */

src/main/java/com/lenis0012/bukkit/loginsecurity/commands/CommandLogin.java

@@ -12,8 +12,10 @@
 import com.lenis0012.bukkit.loginsecurity.session.action.LoginAction;
 import com.lenis0012.bukkit.loginsecurity.storage.PlayerProfile;
 import com.lenis0012.bukkit.loginsecurity.util.MetaData;
+import com.lenis0012.bukkit.loginsecurity.util.OpNotifier;
 import com.lenis0012.pluginutils.command.Command;
 import org.bukkit.Bukkit;
+import org.bukkit.BanList;
 import org.bukkit.entity.Player;
 
 import java.util.logging.Level;
@@ -35,7 +37,18 @@ public void execute() {
         LoginSecurityConfig config = LoginSecurity.getConfiguration();
         int tries = MetaData.incrementAndGet(player, "ls_login_tries");
         if(tries > config.getMaxLoginTries()) {
-            player.kickPlayer("[LoginSecurity] " + translate(LOGIN_TRIES_EXCEEDED).param("max", config.getMaxLoginTries()).toString());
+	    if(config.isBanBruteforceAttempt()) {
+		if(config.isBanNotifyOps()) {
+		    OpNotifier.notify("[LoginSecurity] " + player.getAddress().getHostString() +
+						" " + translate(BAN_BRUTEFORCE_ATTEMPT) + player.getName());
+		}
+		Bukkit.getBanList(BanList.Type.IP).addBan(player.getAddress().getHostString(), 
+					    translate(BAN_BRUTEFORCE_ATTEMPT).toString() + player.getName(),
+					    null, "LoginSecurity");
+                player.kickPlayer("[LoginSecurity] " + translate(BAN_BRUTEFORCE_ATTEMPT) + player.getName());
+	    } else {
+                player.kickPlayer("[LoginSecurity] " + translate(LOGIN_TRIES_EXCEEDED).param("max", config.getMaxLoginTries()).toString());
+	    }
             return;
         }
 

src/main/java/com/lenis0012/bukkit/loginsecurity/modules/general/PlayerListener.java

@@ -12,9 +12,11 @@
 import com.lenis0012.bukkit.loginsecurity.storage.PlayerProfile;
 import com.lenis0012.bukkit.loginsecurity.util.MetaData;
 import com.lenis0012.bukkit.loginsecurity.util.UserIdMode;
+import com.lenis0012.bukkit.loginsecurity.util.OpNotifier;
 import io.papermc.lib.PaperLib;
 import org.bukkit.Bukkit;
 import org.bukkit.Location;
+import org.bukkit.BanList;
 import org.bukkit.entity.EntityType;
 import org.bukkit.entity.HumanEntity;
 import org.bukkit.entity.Player;
@@ -66,21 +68,36 @@ public PlayerListener(GeneralModule general) {
 
     @EventHandler(priority = EventPriority.LOWEST)
     public void onPlayerPreLogin(AsyncPlayerPreLoginEvent event) {
+        final LoginSecurityConfig config = LoginSecurity.getConfiguration();
         // Check if player already online
         for(Player player : Bukkit.getOnlinePlayers()) {
             if(player.getName().equalsIgnoreCase(event.getName())) {
                 PlayerSession session = LoginSecurity.getSessionManager().getPlayerSession(player);
                 if(session.isAuthorized()) {
-                    event.setLoginResult(Result.KICK_OTHER);
-                    event.setKickMessage("[LoginSecurity] " + translate(KICK_ALREADY_ONLINE));
+		    if(config.isBanSimultaneous()) {
+		    	BanList banlist = Bukkit.getBanList(BanList.Type.IP);
+			if(!banlist.isBanned(event.getAddress().getHostAddress())) {
+		    	    banlist.addBan(event.getAddress().getHostAddress(), 
+					    translate(BAN_ALREADY_ONLINE).toString() + player.getName(),
+					    null, "LoginSecurity");
+			    if(config.isBanNotifyOps()) {
+			        OpNotifier.notify("[LoginSecurity] " + event.getAddress().getHostAddress() +
+						" " + translate(BAN_ALREADY_ONLINE) + player.getName());
+			    }
+			}
+                    	event.setLoginResult(Result.KICK_BANNED);
+                    	event.setKickMessage("[LoginSecurity] " + translate(BAN_ALREADY_ONLINE) + player.getName());
+		    } else {
+                    	event.setLoginResult(Result.KICK_OTHER);
+                    	event.setKickMessage("[LoginSecurity] " + translate(KICK_ALREADY_ONLINE));
+		    }
                     return;
                 }
             }
         }
 
         // Verify name
         final String name = event.getName();
-        final LoginSecurityConfig config = LoginSecurity.getConfiguration();
         if(config.isFilterSpecialChars() && !name.replaceAll("[^a-zA-Z0-9_]", "").equals(name)) {
             event.setLoginResult(Result.KICK_OTHER);
             event.setKickMessage("[LoginSecurity] " + translate(KICK_USERNAME_CHARS));

src/main/java/com/lenis0012/bukkit/loginsecurity/modules/language/LanguageKeys.java

@@ -72,7 +72,12 @@ public enum LanguageKeys {
     KICK_USERNAME_CHARS("kickUsernameChars"),
     KICK_USERNAME_LENGTH("kickUsernameLength"),
     KICK_TIME_OUT("kickTimeOut"),
-    KICK_USERNAME_REGISTERED("kickUsernameRegistered");
+    KICK_USERNAME_REGISTERED("kickUsernameRegistered"),
+    /**
+     * Ban messages
+     */
+    BAN_ALREADY_ONLINE("banAlreadyOnline"),
+    BAN_BRUTEFORCE_ATTEMPT("banBruteforceAttempt");
 
     private final String value;
 

src/main/java/com/lenis0012/bukkit/loginsecurity/util/OpNotifier.java

@@ -0,0 +1,17 @@
+package com.lenis0012.bukkit.loginsecurity.util;
+
+import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+
+public class OpNotifier {
+    /**
+     * Send out a message to all server OPs
+     */
+    public static void notify(String message) {
+        for (Player p : Bukkit.getOnlinePlayers()) {
+            if (p.isOp()) {
+                p.sendMessage(message);
+            }
+    	}
+    }
+}