mirror of
https://github.com/vanitasvitae/Smack.git
synced 2024-09-27 10:09:32 +02:00
121 lines
4.9 KiB
Java
121 lines
4.9 KiB
Java
/**
|
|
*
|
|
* Copyright 2013-2018 Florian Schmaus
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
package org.jivesoftware.smack.util.dns;
|
|
|
|
import java.net.InetAddress;
|
|
import java.net.UnknownHostException;
|
|
import java.util.Arrays;
|
|
import java.util.List;
|
|
import java.util.logging.Level;
|
|
import java.util.logging.Logger;
|
|
|
|
import org.jivesoftware.smack.ConnectionConfiguration.DnssecMode;
|
|
|
|
import org.minidns.dnsname.DnsName;
|
|
|
|
/**
|
|
* Implementations of this interface define a class that is capable of resolving DNS addresses.
|
|
*
|
|
*/
|
|
public abstract class DNSResolver {
|
|
|
|
protected static final Logger LOGGER = Logger.getLogger(DNSResolver.class.getName());
|
|
|
|
private final boolean supportsDnssec;
|
|
|
|
protected DNSResolver(boolean supportsDnssec) {
|
|
this.supportsDnssec = supportsDnssec;
|
|
}
|
|
|
|
/**
|
|
* Gets a list of service records for the specified service.
|
|
* @param name The symbolic name of the service.
|
|
* @param failedAddresses list of failed addresses.
|
|
* @param dnssecMode security mode.
|
|
* @return The list of SRV records mapped to the service name.
|
|
*/
|
|
public final List<SRVRecord> lookupSRVRecords(DnsName name, List<HostAddress> failedAddresses, DnssecMode dnssecMode) {
|
|
checkIfDnssecRequestedAndSupported(dnssecMode);
|
|
return lookupSRVRecords0(name, failedAddresses, dnssecMode);
|
|
}
|
|
|
|
protected abstract List<SRVRecord> lookupSRVRecords0(DnsName name, List<HostAddress> failedAddresses, DnssecMode dnssecMode);
|
|
|
|
public final HostAddress lookupHostAddress(DnsName name, int port, List<HostAddress> failedAddresses, DnssecMode dnssecMode) {
|
|
checkIfDnssecRequestedAndSupported(dnssecMode);
|
|
List<InetAddress> inetAddresses = lookupHostAddress0(name, failedAddresses, dnssecMode);
|
|
if (inetAddresses == null || inetAddresses.isEmpty()) {
|
|
return null;
|
|
}
|
|
return new HostAddress(name, port, inetAddresses);
|
|
}
|
|
|
|
/**
|
|
* Lookup the IP addresses of a given host name. Returns <code>null</code> if there was an error, in which the error
|
|
* reason will be added in form of a <code>HostAddress</code> to <code>failedAddresses</code>. Returns a empty list
|
|
* in case the DNS name exists but has no associated A or AAAA resource records. Otherwise, if the resolution was
|
|
* successful <em>and</em> there is at least one A or AAAA resource record, then a non-empty list will be returned.
|
|
* <p>
|
|
* Concrete DNS resolver implementations are free to overwrite this, but have to stick to the interface contract.
|
|
* </p>
|
|
*
|
|
* @param name the DNS name to lookup
|
|
* @param failedAddresses a list with the failed addresses
|
|
* @param dnssecMode the selected DNSSEC mode
|
|
* @return A list, either empty or non-empty, or <code>null</code>
|
|
*/
|
|
protected List<InetAddress> lookupHostAddress0(DnsName name, List<HostAddress> failedAddresses, DnssecMode dnssecMode) {
|
|
// Default implementation of a DNS name lookup for A/AAAA records. It is assumed that this method does never
|
|
// support DNSSEC. Subclasses are free to override this method.
|
|
if (dnssecMode != DnssecMode.disabled) {
|
|
throw new UnsupportedOperationException("This resolver does not support DNSSEC");
|
|
}
|
|
|
|
InetAddress[] inetAddressArray;
|
|
try {
|
|
inetAddressArray = InetAddress.getAllByName(name.toString());
|
|
} catch (UnknownHostException e) {
|
|
failedAddresses.add(new HostAddress(name, e));
|
|
return null;
|
|
}
|
|
|
|
return Arrays.asList(inetAddressArray);
|
|
}
|
|
|
|
protected final boolean shouldContinue(CharSequence name, CharSequence hostname, List<InetAddress> hostAddresses) {
|
|
if (hostAddresses == null) {
|
|
return true;
|
|
}
|
|
|
|
// If hostAddresses is not null but empty, then the DNS resolution was successful but the domain did not
|
|
// have any A or AAAA resource records.
|
|
if (hostAddresses.isEmpty()) {
|
|
LOGGER.log(Level.INFO, "The DNS name " + name + ", points to a hostname (" + hostname
|
|
+ ") which has neither A or AAAA resource records. This is an indication of a broken DNS setup.");
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
private void checkIfDnssecRequestedAndSupported(DnssecMode dnssecMode) {
|
|
if (dnssecMode != DnssecMode.disabled && !supportsDnssec) {
|
|
throw new UnsupportedOperationException("This resolver does not support DNSSEC");
|
|
}
|
|
}
|
|
}
|