83 lines
3.1 KiB
Java
83 lines
3.1 KiB
Java
/**
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*
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* Copyright 2013-2016 Florian Schmaus
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.jivesoftware.smack.util.dns;
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import java.net.InetAddress;
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import java.net.UnknownHostException;
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import java.util.Arrays;
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import java.util.List;
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import org.jivesoftware.smack.ConnectionConfiguration.DnssecMode;
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/**
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* Implementations of this interface define a class that is capable of resolving DNS addresses.
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*
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*/
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public abstract class DNSResolver {
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private final boolean supportsDnssec;
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protected DNSResolver(boolean supportsDnssec) {
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this.supportsDnssec = supportsDnssec;
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}
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/**
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* Gets a list of service records for the specified service.
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* @param name The symbolic name of the service.
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* @return The list of SRV records mapped to the service name.
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*/
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public final List<SRVRecord> lookupSRVRecords(String name, List<HostAddress> failedAddresses, DnssecMode dnssecMode) {
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checkIfDnssecRequestedAndSupported(dnssecMode);
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return lookupSRVRecords0(name, failedAddresses, dnssecMode);
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}
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protected abstract List<SRVRecord> lookupSRVRecords0(String name, List<HostAddress> failedAddresses, DnssecMode dnssecMode);
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public final HostAddress lookupHostAddress(String name, List<HostAddress> failedAddresses, DnssecMode dnssecMode) {
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checkIfDnssecRequestedAndSupported(dnssecMode);
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List<InetAddress> inetAddresses = lookupHostAddress0(name, failedAddresses, dnssecMode);
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if (inetAddresses == null) {
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return null;
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}
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return new HostAddress(name, inetAddresses);
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}
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protected List<InetAddress> lookupHostAddress0(String name, List<HostAddress> failedAddresses, DnssecMode dnssecMode) {
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// Default implementation of a DNS name lookup for A/AAAA records. It is assumed that this method does never
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// support DNSSEC. Subclasses are free to override this method.
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if (dnssecMode != DnssecMode.disabled) {
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throw new UnsupportedOperationException("This resolver does not support DNSSEC");
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}
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InetAddress[] inetAddressArray;
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try {
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inetAddressArray = InetAddress.getAllByName(name);
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} catch (UnknownHostException e) {
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failedAddresses.add(new HostAddress(name, e));
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return null;
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}
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return Arrays.asList(inetAddressArray);
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}
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private final void checkIfDnssecRequestedAndSupported(DnssecMode dnssecMode) {
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if (dnssecMode != DnssecMode.disabled && !supportsDnssec) {
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throw new UnsupportedOperationException("This resolver does not support DNSSEC");
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}
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}
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}
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