001 /****************************************************************
002 * Licensed to the Apache Software Foundation (ASF) under one *
003 * or more contributor license agreements. See the NOTICE file *
004 * distributed with this work for additional information *
005 * regarding copyright ownership. The ASF licenses this file *
006 * to you under the Apache License, Version 2.0 (the *
007 * "License"); you may not use this file except in compliance *
008 * with the License. You may obtain a copy of the License at *
009 * *
010 * http://www.apache.org/licenses/LICENSE-2.0 *
011 * *
012 * Unless required by applicable law or agreed to in writing, *
013 * software distributed under the License is distributed on an *
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY *
015 * KIND, either express or implied. See the License for the *
016 * specific language governing permissions and limitations *
017 * under the License. *
018 ****************************************************************/
019
020
021 package org.apache.james.protocols.smtp.core.fastfail;
022
023 import org.apache.james.protocols.smtp.SMTPSession;
024 import org.apache.james.protocols.smtp.hook.HookResult;
025 import org.apache.james.protocols.smtp.hook.HookReturnCode;
026 import org.apache.james.protocols.smtp.hook.UnknownHook;
027
028 /**
029 * {@link UnknownHook} implementation which disconnect the client after a issue to many unknown commands
030 *
031 *
032 */
033 public class MaxUnknownCmdHandler implements UnknownHook{
034
035 public final static int DEFAULT_MAX_UNKOWN = 5;
036
037 private final static String UNKOWN_COMMAND_COUNT = "UNKNOWN_COMMAND_COUNT";
038 private int maxUnknown;
039
040 public void setMaxUnknownCmdCount(int maxUnknown) {
041 this.maxUnknown = maxUnknown;
042 }
043
044 @Override
045 public HookResult doUnknown(SMTPSession session, String command) {
046 Integer count = (Integer) session.getState().get(UNKOWN_COMMAND_COUNT);
047 if (count == null) {
048 count = 1;
049 } else {
050 count++;
051 }
052 session.getState().put(UNKOWN_COMMAND_COUNT, count);
053 if (count > maxUnknown) {
054 return new HookResult(HookReturnCode.DENY | HookReturnCode.DISCONNECT, "521", "Closing connection as to many unknown commands received");
055
056 } else {
057
058 return new HookResult(HookReturnCode.DECLINED);
059 }
060 }
061
062
063 }