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SMACK-225 Fixed DNS SRV handling, as per RFC 2782. Added support for multiple DNS SRV resolvers namely javax and org.xbill.dns (aka dnsjava). 

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/branches/smack_3_3_0@13561 b35dd754-fafc-0310-a699-88a17e54d16e
This commit is contained in:
Florian Schmaus 2013-03-18 08:53:11 +00:00 committed by flow
parent 21be8c55ee
commit 2eb13f48d2
12 changed files with 756 additions and 210 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
build/eclipse/classpath
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@ -28,5 +28,6 @@
<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
<classpathentry kind="lib" path="build/junit-4.10.jar"/>
<classpathentry kind="lib" path="build/merge/jzlib.jar"/>
<classpathentry kind="lib" path="build/merge/org.xbill.dns_2.1.4.jar"/>
<classpathentry kind="output" path="target/classes"/>
</classpath>

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build/merge/org.xbill.dns_2.1.4.jar Normal file
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9
build/resources/META-INF/smack-config.xml
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@ -5,15 +5,16 @@
<!-- Classes that will be loaded when Smack starts -->
<startupClasses>
<className>org.jivesoftware.smackx.ServiceDiscoveryManager</className>
<className>org.jivesoftware.smack.PrivacyListManager</className>
<className>org.jivesoftware.smack.PrivacyListManager</className>
<className>org.jivesoftware.smackx.XHTMLManager</className>
<className>org.jivesoftware.smackx.muc.MultiUserChat</className>
<className>org.jivesoftware.smackx.bytestreams.ibb.InBandBytestreamManager</className>
<className>org.jivesoftware.smackx.bytestreams.socks5.Socks5BytestreamManager</className>
<className>org.jivesoftware.smackx.bytestreams.socks5.Socks5BytestreamManager</className>
<className>org.jivesoftware.smackx.filetransfer.FileTransferManager</className>
<className>org.jivesoftware.smackx.LastActivityManager</className>
<className>org.jivesoftware.smack.ReconnectionManager</className>
<className>org.jivesoftware.smackx.commands.AdHocCommandManager</className>
<className>org.jivesoftware.smack.ReconnectionManager</className>
<className>org.jivesoftware.smackx.commands.AdHocCommandManager</className>
<className>org.jivesoftware.smack.util.dns.JavaxResolver</className>
</startupClasses>
<!-- Packet reply timeout in milliseconds -->

54
source/org/jivesoftware/smack/ConnectionConfiguration.java
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@ -22,11 +22,15 @@ package org.jivesoftware.smack;
import org.jivesoftware.smack.proxy.ProxyInfo;
import org.jivesoftware.smack.util.DNSUtil;
import org.jivesoftware.smack.util.dns.HostAddress;
import javax.net.SocketFactory;
import javax.net.ssl.SSLContext;
import javax.security.auth.callback.CallbackHandler;
import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* Configuration to use while establishing the connection to the server. It is possible to
@ -48,6 +52,7 @@ public class ConnectionConfiguration implements Cloneable {
private String host;
private int port;
protected List<HostAddress> hostAddresses;
private String truststorePath;
private String truststoreType;
@ -98,12 +103,11 @@ public class ConnectionConfiguration implements Cloneable {
*/
public ConnectionConfiguration(String serviceName) {
// Perform DNS lookup to get host and port to use
DNSUtil.HostAddress address = DNSUtil.resolveXMPPDomain(serviceName);
init(address.getHost(), address.getPort(), serviceName,
ProxyInfo.forDefaultProxy());
hostAddresses = DNSUtil.resolveXMPPDomain(serviceName);
init(serviceName, ProxyInfo.forDefaultProxy());
}
/**
/**
* Creates a new ConnectionConfiguration for the specified service name
* with specified proxy.
* A DNS SRV lookup will be performed to find out the actual host address
@ -114,8 +118,8 @@ public class ConnectionConfiguration implements Cloneable {
*/
public ConnectionConfiguration(String serviceName,ProxyInfo proxy) {
// Perform DNS lookup to get host and port to use
DNSUtil.HostAddress address = DNSUtil.resolveXMPPDomain(serviceName);
init(address.getHost(), address.getPort(), serviceName, proxy);
hostAddresses = DNSUtil.resolveXMPPDomain(serviceName);
init(serviceName, proxy);
}
/**
@ -133,7 +137,8 @@ public class ConnectionConfiguration implements Cloneable {
* @param serviceName the name of the service provided by an XMPP server.
*/
public ConnectionConfiguration(String host, int port, String serviceName) {
init(host, port, serviceName, ProxyInfo.forDefaultProxy());
initHostAddresses(host, port);
init(serviceName, ProxyInfo.forDefaultProxy());
}
/**
@ -152,7 +157,8 @@ public class ConnectionConfiguration implements Cloneable {
* @param proxy the proxy through which XMPP is to be connected
*/
public ConnectionConfiguration(String host, int port, String serviceName, ProxyInfo proxy) {
init(host, port, serviceName, proxy);
initHostAddresses(host, port);
init(serviceName, proxy);
}
/**
@ -163,7 +169,8 @@ public class ConnectionConfiguration implements Cloneable {
* @param port the port where the XMPP is listening.
*/
public ConnectionConfiguration(String host, int port) {
init(host, port, host, ProxyInfo.forDefaultProxy());
initHostAddresses(host, port);
init(host, ProxyInfo.forDefaultProxy());
}
/**
@ -175,12 +182,11 @@ public class ConnectionConfiguration implements Cloneable {
* @param proxy the proxy through which XMPP is to be connected
*/
public ConnectionConfiguration(String host, int port, ProxyInfo proxy) {
init(host, port, host, proxy);
initHostAddresses(host, port);
init(host, proxy);
}
private void init(String host, int port, String serviceName, ProxyInfo proxy) {
this.host = host;
this.port = port;
protected void init(String serviceName, ProxyInfo proxy) {
this.serviceName = serviceName;
this.proxy = proxy;
@ -243,6 +249,11 @@ public class ConnectionConfiguration implements Cloneable {
return port;
}
public void setUsedHostAddress(HostAddress hostAddress) {
this.host = hostAddress.getFQDN();
this.port = hostAddress.getPort();
}
/**
* Returns the TLS security mode used when making the connection. By default,
* the mode is {@link SecurityMode#enabled}.
@ -674,6 +685,10 @@ public class ConnectionConfiguration implements Cloneable {
return this.socketFactory;
}
public List<HostAddress> getHostAddresses() {
return Collections.unmodifiableList(hostAddresses);
}
/**
* An enumeration for TLS security modes that are available when making a connection
* to the XMPP server.
@ -742,4 +757,15 @@ public class ConnectionConfiguration implements Cloneable {
this.password = password;
this.resource = resource;
}
private void initHostAddresses(String host, int port) {
hostAddresses = new ArrayList<HostAddress>(1);
HostAddress hostAddress;
try {
hostAddress = new HostAddress(host, port);
} catch (Exception e) {
throw new IllegalStateException(e);
}
hostAddresses.add(hostAddress);
}
}

72
source/org/jivesoftware/smack/XMPPConnection.java
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@ -26,6 +26,7 @@ import org.jivesoftware.smack.packet.Packet;
import org.jivesoftware.smack.packet.Presence;
import org.jivesoftware.smack.packet.XMPPError;
import org.jivesoftware.smack.util.StringUtils;
import org.jivesoftware.smack.util.dns.HostAddress;
import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
@ -51,6 +52,9 @@ import java.security.KeyStore;
import java.security.Provider;
import java.security.Security;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
/**
* Creates a socket connection to a XMPP server. This is the default connection
@ -546,27 +550,57 @@ public class XMPPConnection extends Connection {
}
private void connectUsingConfiguration(ConnectionConfiguration config) throws XMPPException {
String host = config.getHost();
int port = config.getPort();
try {
if (config.getSocketFactory() == null) {
this.socket = new Socket(host, port);
XMPPException exception = null;
Iterator<HostAddress> it = config.getHostAddresses().iterator();
List<HostAddress> failedAddresses = new LinkedList<HostAddress>();
boolean xmppIOError = false;
while (it.hasNext()) {
exception = null;
HostAddress hostAddress = it.next();
String host = hostAddress.getFQDN();
int port = hostAddress.getPort();
try {
if (config.getSocketFactory() == null) {
this.socket = new Socket(host, port);
}
else {
this.socket = config.getSocketFactory().createSocket(host, port);
}
} catch (UnknownHostException uhe) {
String errorMessage = "Could not connect to " + host + ":" + port + ".";
exception = new XMPPException(errorMessage, new XMPPError(XMPPError.Condition.remote_server_timeout,
errorMessage), uhe);
} catch (IOException ioe) {
String errorMessage = "XMPPError connecting to " + host + ":" + port + ".";
exception = new XMPPException(errorMessage, new XMPPError(XMPPError.Condition.remote_server_error,
errorMessage), ioe);
xmppIOError = true;
}
else {
this.socket = config.getSocketFactory().createSocket(host, port);
if (exception == null) {
// We found a host to connect to, break here
config.setUsedHostAddress(hostAddress);
break;
}
hostAddress.setException(exception);
failedAddresses.add(hostAddress);
if (!it.hasNext()) {
// There are no more host addresses to try
// throw an exception and report all tried
// HostAddresses in the exception
StringBuilder sb = new StringBuilder();
for (HostAddress fha : failedAddresses) {
sb.append(fha.getErrorMessage());
sb.append("; ");
}
XMPPError xmppError;
if (xmppIOError) {
xmppError = new XMPPError(XMPPError.Condition.remote_server_error);
}
else {
xmppError = new XMPPError(XMPPError.Condition.remote_server_timeout);
}
throw new XMPPException(sb.toString(), xmppError);
}
}
catch (UnknownHostException uhe) {
String errorMessage = "Could not connect to " + host + ":" + port + ".";
throw new XMPPException(errorMessage, new XMPPError(
XMPPError.Condition.remote_server_timeout, errorMessage),
uhe);
}
catch (IOException ioe) {
String errorMessage = "XMPPError connecting to " + host + ":"
+ port + ".";
throw new XMPPException(errorMessage, new XMPPError(
XMPPError.Condition.remote_server_error, errorMessage), ioe);
}
socketClosed = false;
initConnection();

318
source/org/jivesoftware/smack/util/DNSUtil.java
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@ -19,18 +19,20 @@
package org.jivesoftware.smack.util;
import java.util.Hashtable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.SortedMap;
import java.util.TreeMap;
import javax.naming.NamingEnumeration;
import javax.naming.directory.Attribute;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import javax.naming.directory.InitialDirContext;
import org.jivesoftware.smack.util.dns.DNSResolver;
import org.jivesoftware.smack.util.dns.HostAddress;
import org.jivesoftware.smack.util.dns.SRVRecord;
/**
* Utilty class to perform DNS lookups for XMPP services.
* Utility class to perform DNS lookups for XMPP services.
*
* @author Matt Tucker
*/
@ -40,23 +42,30 @@ public class DNSUtil {
* Create a cache to hold the 100 most recently accessed DNS lookups for a period of
* 10 minutes.
*/
private static Map<String, HostAddress> cache = new Cache<String, HostAddress>(100, 1000*60*10);
private static Map<String, List<HostAddress>> cache = new Cache<String, List<HostAddress>>(100, 1000*60*10);
private static DirContext context;
private static DNSResolver dnsResolver = null;
static {
try {
Hashtable<String, String> env = new Hashtable<String, String>();
env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
context = new InitialDirContext(env);
}
catch (Exception e) {
// Ignore.
}
/**
* Set the DNS resolver that should be used to perform DNS lookups.
*
* @param resolver
*/
public static void setDNSResolver(DNSResolver resolver) {
dnsResolver = resolver;
}
/**
* Returns the host name and port that the specified XMPP server can be
* Returns the current DNS resolved used to perform DNS lookups.
*
* @return
*/
public static DNSResolver getDNSResolver() {
return dnsResolver;
}
/**
* Returns a list of HostAddresses under which the specified XMPP server can be
* reached at for client-to-server communication. A DNS lookup for a SRV
* record in the form "_xmpp-client._tcp.example.com" is attempted, according
* to section 14.4 of RFC 3920. If that lookup fails, a lookup in the older form
@ -67,81 +76,17 @@ public class DNSUtil {
* of 5222.<p>
*
* As an example, a lookup for "example.com" may return "im.example.com:5269".
*
* Note on SRV record selection.
* We now check priority and weight, but we still don't do this correctly.
* The missing behavior is this: if we fail to reach a host based on its SRV
* record then we need to select another host from the other SRV records.
* In Smack 3.1.1 we're not going to be able to do the major system redesign to
* correct this.
*
* @param domain the domain.
* @return a HostAddress, which encompasses the hostname and port that the XMPP
* server can be reached at for the specified domain.
* @return List of HostAddress, which encompasses the hostname and port that the
* XMPP server can be reached at for the specified domain.
*/
public static HostAddress resolveXMPPDomain(String domain) {
if (context == null) {
return new HostAddress(domain, 5222);
}
String key = "c" + domain;
// Return item from cache if it exists.
if (cache.containsKey(key)) {
HostAddress address = (HostAddress)cache.get(key);
if (address != null) {
return address;
}
}
String bestHost = domain;
int bestPort = 5222;
int bestPriority = 0;
int bestWeight = 0;
try {
Attributes dnsLookup = context.getAttributes("_xmpp-client._tcp." + domain, new String[]{"SRV"});
Attribute srvAttribute = dnsLookup.get("SRV");
NamingEnumeration<String> srvRecords = (NamingEnumeration<String>) srvAttribute.getAll();
while(srvRecords.hasMore()) {
String srvRecord = srvRecords.next();
String [] srvRecordEntries = srvRecord.split(" ");
int priority = Integer.parseInt(srvRecordEntries[srvRecordEntries.length - 4]);
int port = Integer.parseInt(srvRecordEntries[srvRecordEntries.length-2]);
int weight = Integer.parseInt(srvRecordEntries[srvRecordEntries.length - 3]);
String host = srvRecordEntries[srvRecordEntries.length-1];
// Randomize the weight.
weight *= Math.random() * weight;
if ((bestPriority == 0) || (priority < bestPriority)) {
// Choose a server with the lowest priority.
bestPriority = priority;
bestWeight = weight;
bestHost = host;
bestPort = port;
} else if (priority == bestPriority) {
// When we have like priorities then randomly choose a server based on its weight
// The weights were randomized above.
if (weight > bestWeight) {
bestWeight = weight;
bestHost = host;
bestPort = port;
}
}
}
}
catch (Exception e) {
// Ignore.
}
// Host entries in DNS should end with a ".".
if (bestHost.endsWith(".")) {
bestHost = bestHost.substring(0, bestHost.length()-1);
}
HostAddress address = new HostAddress(bestHost, bestPort);
// Add item to cache.
cache.put(key, address);
return address;
public static List<HostAddress> resolveXMPPDomain(String domain) {
return resolveDomain(domain, 'c');
}
/**
* Returns the host name and port that the specified XMPP server can be
* Returns a list of HostAddresses under which the specified XMPP server can be
* reached at for server-to-server communication. A DNS lookup for a SRV
* record in the form "_xmpp-server._tcp.example.com" is attempted, according
* to section 14.4 of RFC 3920. If that lookup fails, a lookup in the older form
@ -154,104 +99,131 @@ public class DNSUtil {
* As an example, a lookup for "example.com" may return "im.example.com:5269".
*
* @param domain the domain.
* @return a HostAddress, which encompasses the hostname and port that the XMPP
* server can be reached at for the specified domain.
* @return List of HostAddress, which encompasses the hostname and port that the
* XMPP server can be reached at for the specified domain.
*/
public static HostAddress resolveXMPPServerDomain(String domain) {
if (context == null) {
return new HostAddress(domain, 5269);
}
String key = "s" + domain;
public static List<HostAddress> resolveXMPPServerDomain(String domain) {
return resolveDomain(domain, 's');
}
private static List<HostAddress> resolveDomain(String domain, char keyPrefix) {
// Prefix the key with 's' to distinguish him from the client domain lookups
String key = keyPrefix + domain;
// Return item from cache if it exists.
if (cache.containsKey(key)) {
HostAddress address = (HostAddress)cache.get(key);
if (address != null) {
return address;
List<HostAddress> addresses = cache.get(key);
if (addresses != null) {
return addresses;
}
}
String host = domain;
int port = 5269;
try {
Attributes dnsLookup =
context.getAttributes("_xmpp-server._tcp." + domain, new String[]{"SRV"});
String srvRecord = (String)dnsLookup.get("SRV").get();
String [] srvRecordEntries = srvRecord.split(" ");
port = Integer.parseInt(srvRecordEntries[srvRecordEntries.length-2]);
host = srvRecordEntries[srvRecordEntries.length-1];
if (dnsResolver == null)
throw new IllegalStateException("No DNS resolver active.");
List<HostAddress> addresses = new ArrayList<HostAddress>();
// Step one: Do SRV lookups
String srvDomain;
if (keyPrefix == 's') {
srvDomain = "_xmpp-server._tcp." + domain;
} else if (keyPrefix == 'c') {
srvDomain = "_xmpp-client._tcp." + domain;
} else {
srvDomain = domain;
}
catch (Exception e) {
// Attempt lookup with older "jabber" name.
try {
Attributes dnsLookup =
context.getAttributes("_jabber._tcp." + domain, new String[]{"SRV"});
String srvRecord = (String)dnsLookup.get("SRV").get();
String [] srvRecordEntries = srvRecord.split(" ");
port = Integer.parseInt(srvRecordEntries[srvRecordEntries.length-2]);
host = srvRecordEntries[srvRecordEntries.length-1];
}
catch (Exception e2) {
// Ignore.
}
}
// Host entries in DNS should end with a ".".
if (host.endsWith(".")) {
host = host.substring(0, host.length()-1);
}
HostAddress address = new HostAddress(host, port);
List<SRVRecord> srvRecords = dnsResolver.lookupSRVRecords(srvDomain);
List<HostAddress> sortedRecords = sortSRVRecords(srvRecords);
if (sortedRecords != null)
addresses.addAll(sortedRecords);
// Step two: Add the hostname to the end of the list
addresses.add(new HostAddress(domain));
// Add item to cache.
cache.put(key, address);
return address;
cache.put(key, addresses);
return addresses;
}
/**
* Encapsulates a hostname and port.
* Sort a given list of SRVRecords as described in RFC 2782
* Note that we follow the RFC with one exception. In a group of the same priority, only the first entry
* is calculated by random. The others are ore simply ordered by their priority.
*
* @param records
* @return
*/
public static class HostAddress {
protected static List<HostAddress> sortSRVRecords(List<SRVRecord> records) {
// RFC 2782, Usage rules: "If there is precisely one SRV RR, and its Target is "."
// (the root domain), abort."
if (records.size() == 1 && records.get(0).getFQDN().equals("."))
return null;
private String host;
private int port;
// sorting the records improves the performance of the bisection later
Collections.sort(records);
private HostAddress(String host, int port) {
this.host = host;
this.port = port;
}
/**
* Returns the hostname.
*
* @return the hostname.
*/
public String getHost() {
return host;
}
/**
* Returns the port.
*
* @return the port.
*/
public int getPort() {
return port;
}
public String toString() {
return host + ":" + port;
}
public boolean equals(Object o) {
if (this == o) {
return true;
// create the priority buckets
SortedMap<Integer, List<SRVRecord>> buckets = new TreeMap<Integer, List<SRVRecord>>();
for (SRVRecord r : records) {
Integer priority = r.getPriority();
List<SRVRecord> bucket = buckets.get(priority);
// create the list of SRVRecords if it doesn't exist
if (bucket == null) {
bucket = new LinkedList<SRVRecord>();
buckets.put(priority, bucket);
}
if (!(o instanceof HostAddress)) {
return false;
}
final HostAddress address = (HostAddress) o;
if (!host.equals(address.host)) {
return false;
}
return port == address.port;
bucket.add(r);
}
List<HostAddress> res = new ArrayList<HostAddress>(records.size());
for (Integer priority : buckets.keySet()) {
List<SRVRecord> bucket = buckets.get(priority);
int bucketSize;
while ((bucketSize = bucket.size()) > 0) {
int[] totals = new int[bucket.size()];
int running_total = 0;
int count = 0;
int zeroWeight = 1;
for (SRVRecord r : bucket) {
if (r.getWeight() > 0)
zeroWeight = 0;
}
for (SRVRecord r : bucket) {
running_total += (r.getWeight() + zeroWeight);
totals[count] = running_total;
count++;
}
int selectedPos;
if (running_total == 0) {
// If running total is 0, then all weights in this priority
// group are 0. So we simply select one of the weights randomly
// as the other 'normal' algorithm is unable to handle this case
selectedPos = (int) (Math.random() * bucketSize);
} else {
double rnd = Math.random() * running_total;
selectedPos = bisect(totals, rnd);
}
// add the SRVRecord that was randomly chosen on it's weight
// to the start of the result list
SRVRecord chosenSRVRecord = bucket.remove(selectedPos);
res.add(chosenSRVRecord);
}
}
return res;
}
// TODO this is not yet really bisection just a stupid linear search
private static int bisect(int[] array, double value) {
int pos = 0;
for (int element : array) {
if (value < element)
break;
pos++;
}
return pos;
}
}

72
source/org/jivesoftware/smack/util/dns/DNSJavaResolver.java Normal file
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@ -0,0 +1,72 @@
/**
* Copyright 2013 Florian Schmaus
*
* All rights reserved. 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.util.ArrayList;
import java.util.List;
import org.xbill.DNS.Lookup;
import org.xbill.DNS.Record;
import org.xbill.DNS.Type;
public class DNSJavaResolver extends DNSResolver {
private static DNSJavaResolver instance;
private DNSJavaResolver() {
}
public static DNSResolver getInstance() {
if (instance == null) {
instance = new DNSJavaResolver();
}
return instance;
}
@Override
public List<SRVRecord> lookupSRVRecords(String name) {
List<SRVRecord> res = new ArrayList<SRVRecord>();
try {
Lookup lookup = new Lookup(name, Type.SRV);
Record recs[] = lookup.run();
if (recs == null)
return res;
for (Record record : recs) {
org.xbill.DNS.SRVRecord srvRecord = (org.xbill.DNS.SRVRecord) record;
if (srvRecord != null && srvRecord.getTarget() != null) {
String host = srvRecord.getTarget().toString();
int port = srvRecord.getPort();
int priority = srvRecord.getPriority();
int weight = srvRecord.getWeight();
SRVRecord r;
try {
r = new SRVRecord(host, port, priority, weight);
} catch (Exception e) {
continue;
}
res.add(r);
}
}
} catch (Exception e) {
}
return res;
}
}

24
source/org/jivesoftware/smack/util/dns/DNSResolver.java Normal file
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@ -0,0 +1,24 @@
/**
* Copyright 2013 Florian Schmaus
*
* All rights reserved. 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.util.List;
public abstract class DNSResolver {
public abstract List<SRVRecord> lookupSRVRecords(String name);
}

93
source/org/jivesoftware/smack/util/dns/HostAddress.java Normal file
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@ -0,0 +1,93 @@
/**
* Copyright 2013 Florian Schmaus
*
* All rights reserved. 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;
public class HostAddress {
private String fqdn;
private int port;
private Exception exception;
/**
* Creates a new HostAddress with the given FQDN. The port will be set to the default XMPP client port: 5222
*
* @param fqdn
* @throws IllegalArgumentException
*/
public HostAddress(String fqdn) throws IllegalArgumentException {
if (fqdn == null)
throw new IllegalArgumentException("FQDN is null");
if (fqdn.charAt(fqdn.length() - 1) == '.') {
this.fqdn = fqdn.substring(0, fqdn.length() - 1);
}
else {
this.fqdn = fqdn;
}
// Set port to the default port for XMPP client communication
this.port = 5222;
}
public HostAddress(String fqdn, int port) throws IllegalArgumentException {
this(fqdn);
if (port < 0 || port > 65535)
throw new IllegalArgumentException(
"DNS SRV records weight must be a 16-bit unsiged integer (i.e. between 0-65535. Port was: " + port);
this.port = port;
}
public String getFQDN() {
return fqdn;
}
public int getPort() {
return port;
}
public void setException(Exception e) {
this.exception = e;
}
public String toString() {
return fqdn + ":" + port;
}
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof HostAddress)) {
return false;
}
final HostAddress address = (HostAddress) o;
if (!fqdn.equals(address.fqdn)) {
return false;
}
return port == address.port;
}
public String getErrorMessage() {
String error;
if (exception == null) {
error = "No error logged";
}
else {
error = exception.getMessage();
}
return toString() + " Exception: " + error;
}
}

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/**
* Copyright 2013 Florian Schmaus
*
* All rights reserved. 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.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import javax.naming.NamingEnumeration;
import javax.naming.directory.Attribute;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import javax.naming.directory.InitialDirContext;
import org.jivesoftware.smack.util.DNSUtil;
/**
* A DNS resolver (mostly for SRV records), which makes use of the API provided in the javax.* namepsace.
*
* @author Florian Schmaus
*
*/
public class JavaxResolver extends DNSResolver {
private static JavaxResolver instance;
private static DirContext dirContext;
static {
try {
Hashtable<String, String> env = new Hashtable<String, String>();
env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
dirContext = new InitialDirContext(env);
} catch (Exception e) {
// Ignore.
}
// Try to set this DNS resolver as primary one
DNSUtil.setDNSResolver(maybeGetInstance());
}
private JavaxResolver() {
}
public static DNSResolver maybeGetInstance() {
if (instance == null && isSupported()) {
instance = new JavaxResolver();
}
return instance;
}
public static boolean isSupported() {
return dirContext != null;
}
@Override
public List<SRVRecord> lookupSRVRecords(String name) {
List<SRVRecord> res = new ArrayList<SRVRecord>();
try {
Attributes dnsLookup = dirContext.getAttributes(name, new String[]{"SRV"});
Attribute srvAttribute = dnsLookup.get("SRV");
@SuppressWarnings("unchecked")
NamingEnumeration<String> srvRecords = (NamingEnumeration<String>) srvAttribute.getAll();
while (srvRecords.hasMore()) {
String srvRecordString = srvRecords.next();
String[] srvRecordEntries = srvRecordString.split(" ");
int priority = Integer.parseInt(srvRecordEntries[srvRecordEntries.length - 4]);
int port = Integer.parseInt(srvRecordEntries[srvRecordEntries.length - 2]);
int weight = Integer.parseInt(srvRecordEntries[srvRecordEntries.length - 3]);
String host = srvRecordEntries[srvRecordEntries.length - 1];
SRVRecord srvRecord;
try {
srvRecord = new SRVRecord(host, port, priority, weight);
} catch (Exception e) {
continue;
}
res.add(srvRecord);
}
} catch (Exception e) {
}
return res;
}
}

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/**
* Copyright 2013 Florian Schmaus
*
* All rights reserved. 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;
/**
* @see <a href="http://tools.ietf.org/html/rfc2782>RFC 2782: A DNS RR for specifying the location of services (DNS
* SRV)<a>
* @author Florian Schmaus
*
*/
public class SRVRecord extends HostAddress implements Comparable<SRVRecord> {
private int weight;
private int priority;
/**
* Create a new SRVRecord
*
* @param fqdn
* @param port
* @param priority
* @param weight
* @throws IllegalArgumentException
*/
public SRVRecord(String fqdn, int port, int priority, int weight) throws IllegalArgumentException {
super(fqdn, port);
if (weight < 0 || weight > 65535)
throw new IllegalArgumentException(
"DNS SRV records weight must be a 16-bit unsiged integer (i.e. between 0-65535. Weight was: "
+ weight);
if (priority < 0 || priority > 65535)
throw new IllegalArgumentException(
"DNS SRV records priority must be a 16-bit unsiged integer (i.e. between 0-65535. Priority was: "
+ priority);
this.priority = priority;
this.weight = weight;
}
public int getPriority() {
return priority;
}
public int getWeight() {
return weight;
}
public int compareTo(SRVRecord other) {
// According to RFC2782,
// "[a] client MUST attempt to contact the target host with the lowest-numbered priority it can reach".
// This means that a SRV record with a higher priority is 'less' then one with a lower.
int res = other.priority - this.priority;
if (res == 0) {
res = this.weight - other.weight;
}
return res;
}
public String toString() {
return super.toString() + " prio:" + priority + ":w:" + weight;
}
}

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package org.jivesoftware.smack.util;
import static junit.framework.Assert.assertEquals;
import static junit.framework.Assert.assertNotNull;
import static junit.framework.Assert.assertTrue;
import static junit.framework.Assert.fail;
import java.util.ArrayList;
import java.util.List;
import org.jivesoftware.smack.util.dns.DNSJavaResolver;
import org.jivesoftware.smack.util.dns.DNSResolver;
import org.jivesoftware.smack.util.dns.HostAddress;
import org.jivesoftware.smack.util.dns.JavaxResolver;
import org.jivesoftware.smack.util.dns.SRVRecord;
import org.junit.Test;
public class DNSUtilTest {
private static final String igniterealtimeDomain = "igniterealtime.org";
private static final String igniterealtimeXMPPServer = "xmpp." + igniterealtimeDomain;
private static final int igniterealtimeClientPort = 5222;
private static final int igniterealtimeServerPort = 5269;
@Test
public void xmppClientDomainJavaXTest() {
DNSResolver resolver = JavaxResolver.maybeGetInstance();
assertNotNull(resolver);
DNSUtil.setDNSResolver(resolver);
xmppClientDomainTest();
}
@Test
public void xmppServerDomainJavaXTest() {
DNSResolver resolver = JavaxResolver.maybeGetInstance();
assertNotNull(resolver);
DNSUtil.setDNSResolver(resolver);
xmppServerDomainTest();
}
@Test
public void xmppClientDomainDNSJavaTest() {
DNSResolver resolver = DNSJavaResolver.getInstance();
assertNotNull(resolver);
DNSUtil.setDNSResolver(resolver);
xmppClientDomainTest();
}
@Test
public void xmppServerDomainDNSJavaTest() {
DNSResolver resolver = DNSJavaResolver.getInstance();
assertNotNull(resolver);
DNSUtil.setDNSResolver(resolver);
xmppServerDomainTest();
}
@Test
public void sortSRVlowestPrioFirstTest() {
List<HostAddress> sortedRecords = DNSUtil.sortSRVRecords(createSRVRecords());
assertTrue(sortedRecords.get(0).getFQDN().equals("0.20.foo.bar"));
}
@Test
public void sortSRVdistributeOverWeights() {
int weight50 = 0;
int weight20one = 0;
int weight20two = 0;
int weight10 = 0;
for (int i = 0; i < 1000; i++) {
List<HostAddress> sortedRecords = DNSUtil.sortSRVRecords(createSRVRecords());
String host = sortedRecords.get(1).getFQDN();
if (host.equals("5.20.one.foo.bar")) {
weight20one++;
} else if (host.equals("5.20.two.foo.bar")) {
weight20two++;
} else if (host.equals("5.10.foo.bar")) {
weight10++;
} else if (host.equals("5.50.foo.bar")) {
weight50++;
} else {
fail("Wrong host after SRVRecord sorting");
}
}
assertTrue(weight50 > 400 && weight50 < 600);
assertTrue(weight20one > 100 && weight20one < 300);
assertTrue(weight20two > 100 && weight20two < 300);
assertTrue(weight10 > 0&& weight10 < 200);
}
@Test
public void sortSRVdistributeZeroWeights() {
int weightZeroOne = 0;
int weightZeroTwo = 0;
for (int i = 0; i < 1000; i++) {
List<HostAddress> sortedRecords = DNSUtil.sortSRVRecords(createSRVRecords());
// Remove the first 5 records with a lower priority
for (int j = 0; j < 5; j++) {
sortedRecords.remove(0);
}
String host = sortedRecords.remove(0).getFQDN();
if (host.equals("10.0.one.foo.bar")) {
weightZeroOne++;
} else if (host.endsWith("10.0.two.foo.bar")) {
weightZeroTwo++;
} else {
fail("Wrong host after SRVRecord sorting");
}
}
assertTrue(weightZeroOne > 400 && weightZeroOne < 600);
assertTrue(weightZeroTwo > 400 && weightZeroTwo < 600);
}
private void xmppClientDomainTest() {
List<HostAddress> hostAddresses = DNSUtil.resolveXMPPDomain(igniterealtimeDomain);
HostAddress ha = hostAddresses.get(0);
assertEquals(ha.getFQDN(), igniterealtimeXMPPServer);
assertEquals(ha.getPort(), igniterealtimeClientPort);
}
private void xmppServerDomainTest() {
List<HostAddress> hostAddresses = DNSUtil.resolveXMPPServerDomain(igniterealtimeDomain);
HostAddress ha = hostAddresses.get(0);
assertEquals(ha.getFQDN(), igniterealtimeXMPPServer);
assertEquals(ha.getPort(), igniterealtimeServerPort);
}
private static List<SRVRecord> createSRVRecords() {
List<SRVRecord> records = new ArrayList<SRVRecord>();
// We create one record with priority 0 that should also be tried first
// Then 4 records with priority 5 and different weights (50, 20, 20, 10)
// Then 2 records with priority 10 and weight 0 which should be treaded equal
// These records are added in a 'random' way to the list
try {
records.add(new SRVRecord("5.20.one.foo.bar", 42, 5, 20)); // Priority 5, Weight 20
records.add(new SRVRecord("10.0.one.foo.bar", 42, 10, 0)); // Priority 10, Weight 0
records.add(new SRVRecord("5.10.foo.bar", 42, 5, 10)); // Priority 5, Weight 10
records.add(new SRVRecord("10.0.two.foo.bar", 42, 10, 0)); // Priority 10, Weight 0
records.add(new SRVRecord("5.20.two.foo.bar", 42, 5, 20)); // Priority 5, Weight 20
records.add(new SRVRecord("0.20.foo.bar", 42, 0, 20)); // Priority 0, Weight 20
records.add(new SRVRecord("5.50.foo.bar", 42, 5, 50)); // Priority 5, Weight 50
} catch (IllegalArgumentException e) {
// Ignore
}
assertTrue(records.size() > 0);
return records;
}
}