001/**
002 *
003 * Copyright 2013-2016 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.dnsjava;
018
019import java.net.InetAddress;
020import java.util.ArrayList;
021import java.util.List;
022
023import org.jivesoftware.smack.ConnectionConfiguration.DnssecMode;
024import org.jivesoftware.smack.initializer.SmackInitializer;
025import org.jivesoftware.smack.util.DNSUtil;
026import org.jivesoftware.smack.util.dns.DNSResolver;
027import org.jivesoftware.smack.util.dns.HostAddress;
028import org.jivesoftware.smack.util.dns.SRVRecord;
029import org.xbill.DNS.Lookup;
030import org.xbill.DNS.Record;
031import org.xbill.DNS.TextParseException;
032import org.xbill.DNS.Type;
033
034/**
035 * This implementation uses the <a href="http://www.dnsjava.org/">dnsjava</a> implementation for resolving DNS addresses.
036 *
037 */
038public class DNSJavaResolver extends DNSResolver implements SmackInitializer {
039
040    private static DNSJavaResolver instance = new DNSJavaResolver();
041
042    public static DNSResolver getInstance() {
043        return instance;
044    }
045
046    public DNSJavaResolver() {
047        super(false);
048    }
049
050    @Override
051    protected List<SRVRecord> lookupSRVRecords0(String name, List<HostAddress> failedAddresses, DnssecMode dnssecMode) {
052        List<SRVRecord> res = new ArrayList<SRVRecord>();
053
054        Lookup lookup;
055        try {
056            lookup = new Lookup(name, Type.SRV);
057        }
058        catch (TextParseException e) {
059            throw new IllegalStateException(e);
060        }
061
062        Record[] recs = lookup.run();
063        if (recs == null)
064            return res;
065
066        for (Record record : recs) {
067            org.xbill.DNS.SRVRecord srvRecord = (org.xbill.DNS.SRVRecord) record;
068            if (srvRecord != null && srvRecord.getTarget() != null) {
069                String host = srvRecord.getTarget().toString();
070                int port = srvRecord.getPort();
071                int priority = srvRecord.getPriority();
072                int weight = srvRecord.getWeight();
073
074                List<InetAddress> hostAddresses = lookupHostAddress0(host, failedAddresses, dnssecMode);
075                if (hostAddresses == null) {
076                    continue;
077                }
078
079                SRVRecord r = new SRVRecord(host, port, priority, weight, hostAddresses);
080                res.add(r);
081            }
082        }
083
084        return res;
085    }
086
087    public static void setup() {
088        DNSUtil.setDNSResolver(getInstance());
089    }
090
091    @Override
092    public List<Exception> initialize() {
093        setup();
094        return null;
095    }
096
097}