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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 *
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012 * Unless required by applicable law or agreed to in writing, *
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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. *
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019
020 package org.apache.james.protocols.smtp.core.fastfail;
021
022 import java.net.UnknownHostException;
023
024
025 import org.apache.james.protocols.smtp.DNSService;
026 import org.apache.james.protocols.smtp.SMTPRetCode;
027 import org.apache.james.protocols.smtp.SMTPSession;
028 import org.apache.james.protocols.smtp.dsn.DSNStatus;
029 import org.apache.james.protocols.smtp.hook.HeloHook;
030 import org.apache.james.protocols.smtp.hook.HookResult;
031 import org.apache.james.protocols.smtp.hook.HookReturnCode;
032 import org.apache.james.protocols.smtp.hook.RcptHook;
033 import org.apache.mailet.MailAddress;
034
035
036 /**
037 * This CommandHandler can be used to reject not resolvable EHLO/HELO
038 */
039 public class ResolvableEhloHeloHandler implements RcptHook, HeloHook {
040
041 public final static String BAD_EHLO_HELO = "BAD_EHLO_HELO";
042
043 protected DNSService dnsService = null;
044
045 /**
046 * Gets the DNS service.
047 * @return the dnsService
048 */
049 public final DNSService getDNSService() {
050 return dnsService;
051 }
052
053 /**
054 * Sets the DNS service.
055 * @param dnsService the dnsService to set
056 */
057 public final void setDNSService(DNSService dnsService) {
058 this.dnsService = dnsService;
059 }
060
061
062 /**
063 * Check if EHLO/HELO is resolvable
064 *
065 * @param session
066 * The SMTPSession
067 * @param argument
068 * The argument
069 */
070 protected void checkEhloHelo(SMTPSession session, String argument) {
071
072 if (isBadHelo(session, argument)) {
073 session.getState().put(BAD_EHLO_HELO, "true");
074 }
075 }
076
077 /**
078 * @param session the SMTPSession
079 * @param argument the argument
080 * @return true if the helo is bad.
081 */
082 protected boolean isBadHelo(SMTPSession session, String argument) {
083 // try to resolv the provided helo. If it can not resolved do not
084 // accept it.
085 try {
086 dnsService.getByName(argument);
087 } catch (UnknownHostException e) {
088 return true;
089 }
090 return false;
091
092 }
093
094 protected boolean check(SMTPSession session,MailAddress rcpt) {
095 // not reject it
096 if (session.getState().get(BAD_EHLO_HELO) == null) {
097 return false;
098 }
099
100 return true;
101 }
102
103 /**
104 * @see org.apache.james.protocols.smtp.hook.RcptHook#doRcpt(org.apache.james.protocols.smtp.SMTPSession, org.apache.mailet.MailAddress, org.apache.mailet.MailAddress)
105 */
106 public HookResult doRcpt(SMTPSession session, MailAddress sender, MailAddress rcpt) {
107 if (check(session,rcpt)) {
108 return new HookResult(HookReturnCode.DENY,SMTPRetCode.SYNTAX_ERROR_ARGUMENTS,DSNStatus.getStatus(DSNStatus.PERMANENT, DSNStatus.DELIVERY_INVALID_ARG)
109 + " Provided EHLO/HELO " + session.getState().get(SMTPSession.CURRENT_HELO_NAME) + " can not resolved.");
110 } else {
111 return new HookResult(HookReturnCode.DECLINED);
112 }
113 }
114
115 /**
116 * @see org.apache.james.protocols.smtp.hook.HeloHook#doHelo(org.apache.james.protocols.smtp.SMTPSession, java.lang.String)
117 */
118 public HookResult doHelo(SMTPSession session, String helo) {
119 checkEhloHelo(session, helo);
120 return new HookResult(HookReturnCode.DECLINED);
121 }
122
123 }