001/**
002 *
003 * Copyright 2013-2020 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.util.ArrayList;
020import java.util.List;
021
022import org.jivesoftware.smack.ConnectionConfiguration.DnssecMode;
023import org.jivesoftware.smack.initializer.SmackInitializer;
024import org.jivesoftware.smack.util.DNSUtil;
025import org.jivesoftware.smack.util.dns.DNSResolver;
026import org.jivesoftware.smack.util.rce.RemoteConnectionEndpointLookupFailure;
027
028import org.minidns.dnsname.DnsName;
029import org.minidns.record.SRV;
030import org.xbill.DNS.Lookup;
031import org.xbill.DNS.Record;
032import org.xbill.DNS.TextParseException;
033import org.xbill.DNS.Type;
034
035/**
036 * This implementation uses the <a href="http://www.dnsjava.org/">dnsjava</a> implementation for resolving DNS addresses.
037 *
038 */
039public class DNSJavaResolver extends DNSResolver implements SmackInitializer {
040
041    private static final DNSJavaResolver instance = new DNSJavaResolver();
042
043    public static DNSResolver getInstance() {
044        return instance;
045    }
046
047    public DNSJavaResolver() {
048        super(false);
049    }
050
051    @Override
052    protected List<SRV> lookupSrvRecords0(DnsName name, List<RemoteConnectionEndpointLookupFailure> lookupFailures,
053                    DnssecMode dnssecMode) {
054        Lookup lookup;
055        try {
056            lookup = new Lookup(name.ace, Type.SRV);
057        }
058        catch (TextParseException e) {
059            RemoteConnectionEndpointLookupFailure failure = new RemoteConnectionEndpointLookupFailure.DnsLookupFailure(
060                            name, e);
061            lookupFailures.add(failure);
062            return null;
063        }
064
065        Record[] recs = lookup.run();
066        if (recs == null) {
067            // TODO: When does this happen? Do we want/need to record a lookup failure?
068            return null;
069        }
070
071        List<SRV> res = new ArrayList<>();
072        for (Record record : recs) {
073            org.xbill.DNS.SRVRecord srvRecord = (org.xbill.DNS.SRVRecord) record;
074            if (srvRecord != null && srvRecord.getTarget() != null) {
075                DnsName host = DnsName.from(srvRecord.getTarget().toString());
076                int port = srvRecord.getPort();
077                int priority = srvRecord.getPriority();
078                int weight = srvRecord.getWeight();
079
080                SRV r = new SRV(priority, weight, port, host);
081                res.add(r);
082            }
083        }
084
085        return res;
086    }
087
088    public static void setup() {
089        DNSUtil.setDNSResolver(getInstance());
090    }
091
092    @Override
093    public List<Exception> initialize() {
094        setup();
095        return null;
096    }
097
098}