001/** 002 * 003 * Copyright 2014 Florian Schmaus 004 * 005 * Licensed under the Apache License, Version 2.0 (the "License"); 006 * you may not use this file except in compliance with the License. 007 * You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.jivesoftware.smack.util.dns.minidns; 018 019import java.util.LinkedList; 020import java.util.List; 021 022import org.jivesoftware.smack.initializer.SmackInitializer; 023import org.jivesoftware.smack.util.DNSUtil; 024import org.jivesoftware.smack.util.dns.DNSResolver; 025import org.jivesoftware.smack.util.dns.SRVRecord; 026import org.jxmpp.util.cache.ExpirationCache; 027 028import de.measite.minidns.Client; 029import de.measite.minidns.DNSCache; 030import de.measite.minidns.DNSMessage; 031import de.measite.minidns.Question; 032import de.measite.minidns.Record; 033import de.measite.minidns.Record.CLASS; 034import de.measite.minidns.Record.TYPE; 035import de.measite.minidns.record.SRV; 036 037 038/** 039 * This implementation uses the <a href="https://github.com/rtreffer/minidns/">minidns</a> implementation for 040 * resolving DNS addresses. 041 */ 042public class MiniDnsResolver implements SmackInitializer, DNSResolver { 043 044 private static final long ONE_DAY = 24*60*60*1000; 045 private static final MiniDnsResolver instance = new MiniDnsResolver(); 046 private static final ExpirationCache<Question, DNSMessage> cache = new ExpirationCache<Question, DNSMessage>(10, ONE_DAY); 047 private final Client client; 048 049 public MiniDnsResolver() { 050 client = new Client(new DNSCache() { 051 052 @Override 053 public DNSMessage get(Question question) { 054 return cache.get(question); 055 } 056 057 @Override 058 public void put(Question question, DNSMessage message) { 059 long expirationTime = ONE_DAY; 060 for (Record record : message.getAnswers()) { 061 if (record.isAnswer(question)) { 062 expirationTime = record.getTtl(); 063 break; 064 } 065 } 066 cache.put(question, message, expirationTime); 067 } 068 069 }); 070 } 071 072 public static DNSResolver getInstance() { 073 return instance; 074 } 075 076 @Override 077 public List<SRVRecord> lookupSRVRecords(String name) { 078 List<SRVRecord> res = new LinkedList<SRVRecord>(); 079 DNSMessage message = client.query(name, TYPE.SRV, CLASS.IN); 080 if (message == null) { 081 return res; 082 } 083 for (Record record : message.getAnswers()) { 084 SRV srv = (SRV) record.getPayload(); 085 res.add(new SRVRecord(srv.getName(), srv.getPort(), srv.getPriority(), srv.getWeight())); 086 } 087 return res; 088 } 089 090 public static void setup() { 091 DNSUtil.setDNSResolver(getInstance()); 092 } 093 094 @Override 095 public List<Exception> initialize() { 096 setup(); 097 return null; 098 } 099 100}