src/org/xbill/DNS/ZoneTransferIn.java - platform/external/smack - Git at Google

 // Copyright (c) 2003-2004 Brian Wellington (bwelling@xbill.org)
 // Parts of this are derived from lib/dns/xfrin.c from BIND 9; its copyright
 // notice follows.

 /*
  * Copyright (C) 1999-2001  Internet Software Consortium.
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
  * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
  * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
  * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
  * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */

 package org.xbill.DNS;

 import java.io.*;
 import java.net.*;
 import java.util.*;

 /**
  * An incoming DNS Zone Transfer.  To use this class, first initialize an
  * object, then call the run() method.  If run() doesn't throw an exception
  * the result will either be an IXFR-style response, an AXFR-style response,
  * or an indication that the zone is up to date.
  *
  * @author Brian Wellington
  */

 public class ZoneTransferIn {

 private static final int INITIALSOA	= 0;
 private static final int FIRSTDATA	= 1;
 private static final int IXFR_DELSOA	= 2;
 private static final int IXFR_DEL	= 3;
 private static final int IXFR_ADDSOA	= 4;
 private static final int IXFR_ADD	= 5;
 private static final int AXFR		= 6;
 private static final int END		= 7;

 private Name zname;
 private int qtype;
 private int dclass;
 private long ixfr_serial;
 private boolean want_fallback;
 private ZoneTransferHandler handler;

 private SocketAddress localAddress;
 private SocketAddress address;
 private TCPClient client;
 private TSIG tsig;
 private TSIG.StreamVerifier verifier;
 private long timeout = 900 * 1000;

 private int state;
 private long end_serial;
 private long current_serial;
 private Record initialsoa;

 private int rtype;

 public static class Delta {
 	/**
 	 * All changes between two versions of a zone in an IXFR response.
 	 */

 	/** The starting serial number of this delta. */
 	public long start;

 	/** The ending serial number of this delta. */
 	public long end;

 	/** A list of records added between the start and end versions */
 	public List adds;

 	/** A list of records deleted between the start and end versions */
 	public List deletes;

 	private
 	Delta() {
 		adds = new ArrayList();
 		deletes = new ArrayList();
 	}
 }

 public static interface ZoneTransferHandler {
 	/**
 	 * Handles a Zone Transfer.
 	 */

 	/**
 	 * Called when an AXFR transfer begins.
 	 */
 	public void startAXFR() throws ZoneTransferException;

 	/**
 	 * Called when an IXFR transfer begins.
 	 */
 	public void startIXFR() throws ZoneTransferException;

 	/**
 	 * Called when a series of IXFR deletions begins.
 	 * @param soa The starting SOA.
 	 */
 	public void startIXFRDeletes(Record soa) throws ZoneTransferException;

 	/**
 	 * Called when a series of IXFR adds begins.
 	 * @param soa The starting SOA.
 	 */
 	public void startIXFRAdds(Record soa) throws ZoneTransferException;

 	/**
 	 * Called for each content record in an AXFR.
 	 * @param r The DNS record.
 	 */
 	public void handleRecord(Record r) throws ZoneTransferException;
 };

 private static class BasicHandler implements ZoneTransferHandler {
 	private List axfr;
 	private List ixfr;

 	public void startAXFR() {
 		axfr = new ArrayList();
 	}

 	public void startIXFR() {
 		ixfr = new ArrayList();
 	}

 	public void startIXFRDeletes(Record soa) {
 		Delta delta = new Delta();
 		delta.deletes.add(soa);
 		delta.start = getSOASerial(soa);
 		ixfr.add(delta);
 	}

 	public void startIXFRAdds(Record soa) {
 		Delta delta = (Delta) ixfr.get(ixfr.size() - 1);
 		delta.adds.add(soa);
 		delta.end = getSOASerial(soa);
 	}

 	public void handleRecord(Record r) {
 		List list;
 		if (ixfr != null) {
 			Delta delta = (Delta) ixfr.get(ixfr.size() - 1);
 			if (delta.adds.size() > 0)
 				list = delta.adds;
 			else
 				list = delta.deletes;
 		} else
 			list = axfr;
 		list.add(r);
 	}
 };

 private
 ZoneTransferIn() {}

 private
 ZoneTransferIn(Name zone, int xfrtype, long serial, boolean fallback,
 	       SocketAddress address, TSIG key)
 {
 	this.address = address;
 	this.tsig = key;
 	if (zone.isAbsolute())
 		zname = zone;
 	else {
 		try {
 			zname = Name.concatenate(zone, Name.root);
 		}
 		catch (NameTooLongException e) {
 			throw new IllegalArgumentException("ZoneTransferIn: " +
 							   "name too long");
 		}
 	}
 	qtype = xfrtype;
 	dclass = DClass.IN;
 	ixfr_serial = serial;
 	want_fallback = fallback;
 	state = INITIALSOA;
 }

 /**
  * Instantiates a ZoneTransferIn object to do an AXFR (full zone transfer).
  * @param zone The zone to transfer.
  * @param address The host/port from which to transfer the zone.
  * @param key The TSIG key used to authenticate the transfer, or null.
  * @return The ZoneTransferIn object.
  * @throws UnknownHostException The host does not exist.
  */
 public static ZoneTransferIn
 newAXFR(Name zone, SocketAddress address, TSIG key) {
 	return new ZoneTransferIn(zone, Type.AXFR, 0, false, address, key);
 }

 /**
  * Instantiates a ZoneTransferIn object to do an AXFR (full zone transfer).
  * @param zone The zone to transfer.
  * @param host The host from which to transfer the zone.
  * @param port The port to connect to on the server, or 0 for the default.
  * @param key The TSIG key used to authenticate the transfer, or null.
  * @return The ZoneTransferIn object.
  * @throws UnknownHostException The host does not exist.
  */
 public static ZoneTransferIn
 newAXFR(Name zone, String host, int port, TSIG key)
 throws UnknownHostException
 {
 	if (port == 0)
 		port = SimpleResolver.DEFAULT_PORT;
 	return newAXFR(zone, new InetSocketAddress(host, port), key);
 }

 /**
  * Instantiates a ZoneTransferIn object to do an AXFR (full zone transfer).
  * @param zone The zone to transfer.
  * @param host The host from which to transfer the zone.
  * @param key The TSIG key used to authenticate the transfer, or null.
  * @return The ZoneTransferIn object.
  * @throws UnknownHostException The host does not exist.
  */
 public static ZoneTransferIn
 newAXFR(Name zone, String host, TSIG key)
 throws UnknownHostException
 {
 	return newAXFR(zone, host, 0, key);
 }

 /**
  * Instantiates a ZoneTransferIn object to do an IXFR (incremental zone
  * transfer).
  * @param zone The zone to transfer.
  * @param serial The existing serial number.
  * @param fallback If true, fall back to AXFR if IXFR is not supported.
  * @param address The host/port from which to transfer the zone.
  * @param key The TSIG key used to authenticate the transfer, or null.
  * @return The ZoneTransferIn object.
  * @throws UnknownHostException The host does not exist.
  */
 public static ZoneTransferIn
 newIXFR(Name zone, long serial, boolean fallback, SocketAddress address,
 	TSIG key)
 {
 	return new ZoneTransferIn(zone, Type.IXFR, serial, fallback, address,
 				  key);
 }

 /**
  * Instantiates a ZoneTransferIn object to do an IXFR (incremental zone
  * transfer).
  * @param zone The zone to transfer.
  * @param serial The existing serial number.
  * @param fallback If true, fall back to AXFR if IXFR is not supported.
  * @param host The host from which to transfer the zone.
  * @param port The port to connect to on the server, or 0 for the default.
  * @param key The TSIG key used to authenticate the transfer, or null.
  * @return The ZoneTransferIn object.
  * @throws UnknownHostException The host does not exist.
  */
 public static ZoneTransferIn
 newIXFR(Name zone, long serial, boolean fallback, String host, int port,
 	TSIG key)
 throws UnknownHostException
 {
 	if (port == 0)
 		port = SimpleResolver.DEFAULT_PORT;
 	return newIXFR(zone, serial, fallback,
 		       new InetSocketAddress(host, port), key);
 }

 /**
  * Instantiates a ZoneTransferIn object to do an IXFR (incremental zone
  * transfer).
  * @param zone The zone to transfer.
  * @param serial The existing serial number.
  * @param fallback If true, fall back to AXFR if IXFR is not supported.
  * @param host The host from which to transfer the zone.
  * @param key The TSIG key used to authenticate the transfer, or null.
  * @return The ZoneTransferIn object.
  * @throws UnknownHostException The host does not exist.
  */
 public static ZoneTransferIn
 newIXFR(Name zone, long serial, boolean fallback, String host, TSIG key)
 throws UnknownHostException
 {
 	return newIXFR(zone, serial, fallback, host, 0, key);
 }

 /**
  * Gets the name of the zone being transferred.
  */
 public Name
 getName() {
 	return zname;
 }

 /**
  * Gets the type of zone transfer (either AXFR or IXFR).
  */
 public int
 getType() {
 	return qtype;
 }

 /**
  * Sets a timeout on this zone transfer.  The default is 900 seconds (15
  * minutes).
  * @param secs The maximum amount of time that this zone transfer can take.
  */
 public void
 setTimeout(int secs) {
 	if (secs < 0)
 		throw new IllegalArgumentException("timeout cannot be " +
 						   "negative");
 	timeout = 1000L * secs;
 }

 /**
  * Sets an alternate DNS class for this zone transfer.
  * @param dclass The class to use instead of class IN.
  */
 public void
 setDClass(int dclass) {
 	DClass.check(dclass);
 	this.dclass = dclass;
 }

 /**
  * Sets the local address to bind to when sending messages.
  * @param addr The local address to send messages from.
  */
 public void
 setLocalAddress(SocketAddress addr) {
 	this.localAddress = addr;
 }

 private void
 openConnection() throws IOException {
 	long endTime = System.currentTimeMillis() + timeout;
 	client = new TCPClient(endTime);
 	if (localAddress != null)
 		client.bind(localAddress);
 	client.connect(address);
 }

 private void
 sendQuery() throws IOException {
 	Record question = Record.newRecord(zname, qtype, dclass);

 	Message query = new Message();
 	query.getHeader().setOpcode(Opcode.QUERY);
 	query.addRecord(question, Section.QUESTION);
 	if (qtype == Type.IXFR) {
 		Record soa = new SOARecord(zname, dclass, 0, Name.root,
 					   Name.root, ixfr_serial,
 					   0, 0, 0, 0);
 		query.addRecord(soa, Section.AUTHORITY);
 	}
 	if (tsig != null) {
 		tsig.apply(query, null);
 		verifier = new TSIG.StreamVerifier(tsig, query.getTSIG());
 	}
 	byte [] out = query.toWire(Message.MAXLENGTH);
 	client.send(out);
 }

 private static long
 getSOASerial(Record rec) {
 	SOARecord soa = (SOARecord) rec;
 	return soa.getSerial();
 }

 private void
 logxfr(String s) {
 	if (Options.check("verbose"))
 		System.out.println(zname + ": " + s);
 }

 private void
 fail(String s) throws ZoneTransferException {
 	throw new ZoneTransferException(s);
 }

 private void
 fallback() throws ZoneTransferException {
 	if (!want_fallback)
 		fail("server doesn't support IXFR");

 	logxfr("falling back to AXFR");
 	qtype = Type.AXFR;
 	state = INITIALSOA;
 }

 private void
 parseRR(Record rec) throws ZoneTransferException {
 	int type = rec.getType();
 	Delta delta;

 	switch (state) {
 	case INITIALSOA:
 		if (type != Type.SOA)
 			fail("missing initial SOA");
 		initialsoa = rec;
 		// Remember the serial number in the initial SOA; we need it
 		// to recognize the end of an IXFR.
 		end_serial = getSOASerial(rec);
 		if (qtype == Type.IXFR &&
 		    Serial.compare(end_serial, ixfr_serial) <= 0)
 		{
 			logxfr("up to date");
 			state = END;
 			break;
 		}
 		state = FIRSTDATA;
 		break;

 	case FIRSTDATA:
 		// If the transfer begins with 1 SOA, it's an AXFR.
 		// If it begins with 2 SOAs, it's an IXFR.
 		if (qtype == Type.IXFR && type == Type.SOA &&
 		    getSOASerial(rec) == ixfr_serial)
 		{
 			rtype = Type.IXFR;
 			handler.startIXFR();
 			logxfr("got incremental response");
 			state = IXFR_DELSOA;
 		} else {
 			rtype = Type.AXFR;
 			handler.startAXFR();
 			handler.handleRecord(initialsoa);
 			logxfr("got nonincremental response");
 			state = AXFR;
 		}
 		parseRR(rec); // Restart...
 		return;

 	case IXFR_DELSOA:
 		handler.startIXFRDeletes(rec);
 		state = IXFR_DEL;
 		break;

 	case IXFR_DEL:
 		if (type == Type.SOA) {
 			current_serial = getSOASerial(rec);
 			state = IXFR_ADDSOA;
 			parseRR(rec); // Restart...
 			return;
 		}
 		handler.handleRecord(rec);
 		break;

 	case IXFR_ADDSOA:
 		handler.startIXFRAdds(rec);
 		state = IXFR_ADD;
 		break;

 	case IXFR_ADD:
 		if (type == Type.SOA) {
 			long soa_serial = getSOASerial(rec);
 			if (soa_serial == end_serial) {
 				state = END;
 				break;
 			} else if (soa_serial != current_serial) {
 				fail("IXFR out of sync: expected serial " +
 				     current_serial + " , got " + soa_serial);
 			} else {
 				state = IXFR_DELSOA;
 				parseRR(rec); // Restart...
 				return;
 			}
 		}
 		handler.handleRecord(rec);
 		break;

 	case AXFR:
 		// Old BINDs sent cross class A records for non IN classes.
 		if (type == Type.A && rec.getDClass() != dclass)
 			break;
 		handler.handleRecord(rec);
 		if (type == Type.SOA) {
 			state = END;
 		}
 		break;

 	case END:
 		fail("extra data");
 		break;

 	default:
 		fail("invalid state");
 		break;
 	}
 }

 private void
 closeConnection() {
 	try {
 		if (client != null)
 			client.cleanup();
 	}
 	catch (IOException e) {
 	}
 }

 private Message
 parseMessage(byte [] b) throws WireParseException {
 	try {
 		return new Message(b);
 	}
 	catch (IOException e) {
 		if (e instanceof WireParseException)
 			throw (WireParseException) e;
 		throw new WireParseException("Error parsing message");
 	}
 }

 private void
 doxfr() throws IOException, ZoneTransferException {
 	sendQuery();
 	while (state != END) {
 		byte [] in = client.recv();
 		Message response =  parseMessage(in);
 		if (response.getHeader().getRcode() == Rcode.NOERROR &&
 		    verifier != null)
 		{
 			TSIGRecord tsigrec = response.getTSIG();

 			int error = verifier.verify(response, in);
 			if (error != Rcode.NOERROR)
 				fail("TSIG failure");
 		}

 		Record [] answers = response.getSectionArray(Section.ANSWER);

 		if (state == INITIALSOA) {
 			int rcode = response.getRcode();
 			if (rcode != Rcode.NOERROR) {
 				if (qtype == Type.IXFR &&
 				    rcode == Rcode.NOTIMP)
 				{
 					fallback();
 					doxfr();
 					return;
 				}
 				fail(Rcode.string(rcode));
 			}

 			Record question = response.getQuestion();
 			if (question != null && question.getType() != qtype) {
 				fail("invalid question section");
 			}

 			if (answers.length == 0 && qtype == Type.IXFR) {
 				fallback();
 				doxfr();
 				return;
 			}
 		}

 		for (int i = 0; i < answers.length; i++) {
 			parseRR(answers[i]);
 		}

 		if (state == END && verifier != null &&
 		    !response.isVerified())
 			fail("last message must be signed");
 	}
 }

 /**
  * Does the zone transfer.
  * @param handler The callback object that handles the zone transfer data.
  * @throws IOException The zone transfer failed to due an IO problem.
  * @throws ZoneTransferException The zone transfer failed to due a problem
  * with the zone transfer itself.
  */
 public void
 run(ZoneTransferHandler handler) throws IOException, ZoneTransferException {
 	this.handler = handler;
 	try {
 		openConnection();
 		doxfr();
 	}
 	finally {
 		closeConnection();
 	}
 }

 /**
  * Does the zone transfer.
  * @return A list, which is either an AXFR-style response (List of Records),
  * and IXFR-style response (List of Deltas), or null, which indicates that
  * an IXFR was performed and the zone is up to date.
  * @throws IOException The zone transfer failed to due an IO problem.
  * @throws ZoneTransferException The zone transfer failed to due a problem
  * with the zone transfer itself.
  */
 public List
 run() throws IOException, ZoneTransferException {
 	BasicHandler handler = new BasicHandler();
 	run(handler);
 	if (handler.axfr != null)
 		return handler.axfr;
 	return handler.ixfr;
 }

 private BasicHandler
 getBasicHandler() throws IllegalArgumentException {
 	if (handler instanceof BasicHandler)
 		return (BasicHandler) handler;
 	throw new IllegalArgumentException("ZoneTransferIn used callback " +
 					   "interface");
 }

 /**
  * Returns true if the response is an AXFR-style response (List of Records).
  * This will be true if either an IXFR was performed, an IXFR was performed
  * and the server provided a full zone transfer, or an IXFR failed and
  * fallback to AXFR occurred.
  */
 public boolean
 isAXFR() {
 	return (rtype == Type.AXFR);
 }

 /**
  * Gets the AXFR-style response.
  * @throws IllegalArgumentException The transfer used the callback interface,
  * so the response was not stored.
  */
 public List
 getAXFR() {
 	BasicHandler handler = getBasicHandler();
 	return handler.axfr;
 }

 /**
  * Returns true if the response is an IXFR-style response (List of Deltas).
  * This will be true only if an IXFR was performed and the server provided
  * an incremental zone transfer.
  */
 public boolean
 isIXFR() {
 	return (rtype == Type.IXFR);
 }

 /**
  * Gets the IXFR-style response.
  * @throws IllegalArgumentException The transfer used the callback interface,
  * so the response was not stored.
  */
 public List
 getIXFR() {
 	BasicHandler handler = getBasicHandler();
 	return handler.ixfr;
 }

 /**
  * Returns true if the response indicates that the zone is up to date.
  * This will be true only if an IXFR was performed.
  * @throws IllegalArgumentException The transfer used the callback interface,
  * so the response was not stored.
  */
 public boolean
 isCurrent() {
 	BasicHandler handler = getBasicHandler();
 	return (handler.axfr == null && handler.ixfr == null);
 }

 }
	// Copyright (c) 2003-2004 Brian Wellington (bwelling@xbill.org)
	// Parts of this are derived from lib/dns/xfrin.c from BIND 9; its copyright
	// notice follows.

	/*
	* Copyright (C) 1999-2001 Internet Software Consortium.
	*
	* Permission to use, copy, modify, and distribute this software for any
	* purpose with or without fee is hereby granted, provided that the above
	* copyright notice and this permission notice appear in all copies.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
	* DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
	* INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
	* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
	* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
	* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
	* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	*/

	package org.xbill.DNS;

	import java.io.*;
	import java.net.*;
	import java.util.*;

	/**
	* An incoming DNS Zone Transfer. To use this class, first initialize an
	* object, then call the run() method. If run() doesn't throw an exception
	* the result will either be an IXFR-style response, an AXFR-style response,
	* or an indication that the zone is up to date.
	*
	* @author Brian Wellington
	*/

	public class ZoneTransferIn {

	private static final int INITIALSOA = 0;
	private static final int FIRSTDATA = 1;
	private static final int IXFR_DELSOA = 2;
	private static final int IXFR_DEL = 3;
	private static final int IXFR_ADDSOA = 4;
	private static final int IXFR_ADD = 5;
	private static final int AXFR = 6;
	private static final int END = 7;

	private Name zname;
	private int qtype;
	private int dclass;
	private long ixfr_serial;
	private boolean want_fallback;
	private ZoneTransferHandler handler;

	private SocketAddress localAddress;
	private SocketAddress address;
	private TCPClient client;
	private TSIG tsig;
	private TSIG.StreamVerifier verifier;
	private long timeout = 900 * 1000;

	private int state;
	private long end_serial;
	private long current_serial;
	private Record initialsoa;

	private int rtype;

	public static class Delta {
	/**
	* All changes between two versions of a zone in an IXFR response.
	*/

	/** The starting serial number of this delta. */
	public long start;

	/** The ending serial number of this delta. */
	public long end;

	/** A list of records added between the start and end versions */
	public List adds;

	/** A list of records deleted between the start and end versions */
	public List deletes;

	private
	Delta() {
	adds = new ArrayList();
	deletes = new ArrayList();
	}
	}

	public static interface ZoneTransferHandler {
	/**
	* Handles a Zone Transfer.
	*/

	/**
	* Called when an AXFR transfer begins.
	*/
	public void startAXFR() throws ZoneTransferException;

	/**
	* Called when an IXFR transfer begins.
	*/
	public void startIXFR() throws ZoneTransferException;

	/**
	* Called when a series of IXFR deletions begins.
	* @param soa The starting SOA.
	*/
	public void startIXFRDeletes(Record soa) throws ZoneTransferException;

	/**
	* Called when a series of IXFR adds begins.
	* @param soa The starting SOA.
	*/
	public void startIXFRAdds(Record soa) throws ZoneTransferException;

	/**
	* Called for each content record in an AXFR.
	* @param r The DNS record.
	*/
	public void handleRecord(Record r) throws ZoneTransferException;
	};

	private static class BasicHandler implements ZoneTransferHandler {
	private List axfr;
	private List ixfr;

	public void startAXFR() {
	axfr = new ArrayList();
	}

	public void startIXFR() {
	ixfr = new ArrayList();
	}

	public void startIXFRDeletes(Record soa) {
	Delta delta = new Delta();
	delta.deletes.add(soa);
	delta.start = getSOASerial(soa);
	ixfr.add(delta);
	}

	public void startIXFRAdds(Record soa) {
	Delta delta = (Delta) ixfr.get(ixfr.size() - 1);
	delta.adds.add(soa);
	delta.end = getSOASerial(soa);
	}

	public void handleRecord(Record r) {
	List list;
	if (ixfr != null) {
	Delta delta = (Delta) ixfr.get(ixfr.size() - 1);
	if (delta.adds.size() > 0)
	list = delta.adds;
	else
	list = delta.deletes;
	} else
	list = axfr;
	list.add(r);
	}
	};

	private
	ZoneTransferIn() {}

	private
	ZoneTransferIn(Name zone, int xfrtype, long serial, boolean fallback,
	SocketAddress address, TSIG key)
	{
	this.address = address;
	this.tsig = key;
	if (zone.isAbsolute())
	zname = zone;
	else {
	try {
	zname = Name.concatenate(zone, Name.root);
	}
	catch (NameTooLongException e) {
	throw new IllegalArgumentException("ZoneTransferIn: " +
	"name too long");
	}
	}
	qtype = xfrtype;
	dclass = DClass.IN;
	ixfr_serial = serial;
	want_fallback = fallback;
	state = INITIALSOA;
	}

	/**
	* Instantiates a ZoneTransferIn object to do an AXFR (full zone transfer).
	* @param zone The zone to transfer.
	* @param address The host/port from which to transfer the zone.
	* @param key The TSIG key used to authenticate the transfer, or null.
	* @return The ZoneTransferIn object.
	* @throws UnknownHostException The host does not exist.
	*/
	public static ZoneTransferIn
	newAXFR(Name zone, SocketAddress address, TSIG key) {
	return new ZoneTransferIn(zone, Type.AXFR, 0, false, address, key);
	}

	/**
	* Instantiates a ZoneTransferIn object to do an AXFR (full zone transfer).
	* @param zone The zone to transfer.
	* @param host The host from which to transfer the zone.
	* @param port The port to connect to on the server, or 0 for the default.
	* @param key The TSIG key used to authenticate the transfer, or null.
	* @return The ZoneTransferIn object.
	* @throws UnknownHostException The host does not exist.
	*/
	public static ZoneTransferIn
	newAXFR(Name zone, String host, int port, TSIG key)
	throws UnknownHostException
	{
	if (port == 0)
	port = SimpleResolver.DEFAULT_PORT;
	return newAXFR(zone, new InetSocketAddress(host, port), key);
	}

	/**
	* Instantiates a ZoneTransferIn object to do an AXFR (full zone transfer).
	* @param zone The zone to transfer.
	* @param host The host from which to transfer the zone.
	* @param key The TSIG key used to authenticate the transfer, or null.
	* @return The ZoneTransferIn object.
	* @throws UnknownHostException The host does not exist.
	*/
	public static ZoneTransferIn
	newAXFR(Name zone, String host, TSIG key)
	throws UnknownHostException
	{
	return newAXFR(zone, host, 0, key);
	}

	/**
	* Instantiates a ZoneTransferIn object to do an IXFR (incremental zone
	* transfer).
	* @param zone The zone to transfer.
	* @param serial The existing serial number.
	* @param fallback If true, fall back to AXFR if IXFR is not supported.
	* @param address The host/port from which to transfer the zone.
	* @param key The TSIG key used to authenticate the transfer, or null.
	* @return The ZoneTransferIn object.
	* @throws UnknownHostException The host does not exist.
	*/
	public static ZoneTransferIn
	newIXFR(Name zone, long serial, boolean fallback, SocketAddress address,
	TSIG key)
	{
	return new ZoneTransferIn(zone, Type.IXFR, serial, fallback, address,
	key);
	}

	/**
	* Instantiates a ZoneTransferIn object to do an IXFR (incremental zone
	* transfer).
	* @param zone The zone to transfer.
	* @param serial The existing serial number.
	* @param fallback If true, fall back to AXFR if IXFR is not supported.
	* @param host The host from which to transfer the zone.
	* @param port The port to connect to on the server, or 0 for the default.
	* @param key The TSIG key used to authenticate the transfer, or null.
	* @return The ZoneTransferIn object.
	* @throws UnknownHostException The host does not exist.
	*/
	public static ZoneTransferIn
	newIXFR(Name zone, long serial, boolean fallback, String host, int port,
	TSIG key)
	throws UnknownHostException
	{
	if (port == 0)
	port = SimpleResolver.DEFAULT_PORT;
	return newIXFR(zone, serial, fallback,
	new InetSocketAddress(host, port), key);
	}

	/**
	* Instantiates a ZoneTransferIn object to do an IXFR (incremental zone
	* transfer).
	* @param zone The zone to transfer.
	* @param serial The existing serial number.
	* @param fallback If true, fall back to AXFR if IXFR is not supported.
	* @param host The host from which to transfer the zone.
	* @param key The TSIG key used to authenticate the transfer, or null.
	* @return The ZoneTransferIn object.
	* @throws UnknownHostException The host does not exist.
	*/
	public static ZoneTransferIn
	newIXFR(Name zone, long serial, boolean fallback, String host, TSIG key)
	throws UnknownHostException
	{
	return newIXFR(zone, serial, fallback, host, 0, key);
	}

	/**
	* Gets the name of the zone being transferred.
	*/
	public Name
	getName() {
	return zname;
	}

	/**
	* Gets the type of zone transfer (either AXFR or IXFR).
	*/
	public int
	getType() {
	return qtype;
	}

	/**
	* Sets a timeout on this zone transfer. The default is 900 seconds (15
	* minutes).
	* @param secs The maximum amount of time that this zone transfer can take.
	*/
	public void
	setTimeout(int secs) {
	if (secs < 0)
	throw new IllegalArgumentException("timeout cannot be " +
	"negative");
	timeout = 1000L * secs;
	}

	/**
	* Sets an alternate DNS class for this zone transfer.
	* @param dclass The class to use instead of class IN.
	*/
	public void
	setDClass(int dclass) {
	DClass.check(dclass);
	this.dclass = dclass;
	}

	/**
	* Sets the local address to bind to when sending messages.
	* @param addr The local address to send messages from.
	*/
	public void
	setLocalAddress(SocketAddress addr) {
	this.localAddress = addr;
	}

	private void
	openConnection() throws IOException {
	long endTime = System.currentTimeMillis() + timeout;
	client = new TCPClient(endTime);
	if (localAddress != null)
	client.bind(localAddress);
	client.connect(address);
	}

	private void
	sendQuery() throws IOException {
	Record question = Record.newRecord(zname, qtype, dclass);

	Message query = new Message();
	query.getHeader().setOpcode(Opcode.QUERY);
	query.addRecord(question, Section.QUESTION);
	if (qtype == Type.IXFR) {
	Record soa = new SOARecord(zname, dclass, 0, Name.root,
	Name.root, ixfr_serial,
	0, 0, 0, 0);
	query.addRecord(soa, Section.AUTHORITY);
	}
	if (tsig != null) {
	tsig.apply(query, null);
	verifier = new TSIG.StreamVerifier(tsig, query.getTSIG());
	}
	byte [] out = query.toWire(Message.MAXLENGTH);
	client.send(out);
	}

	private static long
	getSOASerial(Record rec) {
	SOARecord soa = (SOARecord) rec;
	return soa.getSerial();
	}

	private void
	logxfr(String s) {
	if (Options.check("verbose"))
	System.out.println(zname + ": " + s);
	}

	private void
	fail(String s) throws ZoneTransferException {
	throw new ZoneTransferException(s);
	}

	private void
	fallback() throws ZoneTransferException {
	if (!want_fallback)
	fail("server doesn't support IXFR");

	logxfr("falling back to AXFR");
	qtype = Type.AXFR;
	state = INITIALSOA;
	}

	private void
	parseRR(Record rec) throws ZoneTransferException {
	int type = rec.getType();
	Delta delta;

	switch (state) {
	case INITIALSOA:
	if (type != Type.SOA)
	fail("missing initial SOA");
	initialsoa = rec;
	// Remember the serial number in the initial SOA; we need it
	// to recognize the end of an IXFR.
	end_serial = getSOASerial(rec);
	if (qtype == Type.IXFR &&
	Serial.compare(end_serial, ixfr_serial) <= 0)
	{
	logxfr("up to date");
	state = END;
	break;
	}
	state = FIRSTDATA;
	break;

	case FIRSTDATA:
	// If the transfer begins with 1 SOA, it's an AXFR.
	// If it begins with 2 SOAs, it's an IXFR.
	if (qtype == Type.IXFR && type == Type.SOA &&
	getSOASerial(rec) == ixfr_serial)
	{
	rtype = Type.IXFR;
	handler.startIXFR();
	logxfr("got incremental response");
	state = IXFR_DELSOA;
	} else {
	rtype = Type.AXFR;
	handler.startAXFR();
	handler.handleRecord(initialsoa);
	logxfr("got nonincremental response");
	state = AXFR;
	}
	parseRR(rec); // Restart...
	return;

	case IXFR_DELSOA:
	handler.startIXFRDeletes(rec);
	state = IXFR_DEL;
	break;

	case IXFR_DEL:
	if (type == Type.SOA) {
	current_serial = getSOASerial(rec);
	state = IXFR_ADDSOA;
	parseRR(rec); // Restart...
	return;
	}
	handler.handleRecord(rec);
	break;

	case IXFR_ADDSOA:
	handler.startIXFRAdds(rec);
	state = IXFR_ADD;
	break;

	case IXFR_ADD:
	if (type == Type.SOA) {
	long soa_serial = getSOASerial(rec);
	if (soa_serial == end_serial) {
	state = END;
	break;
	} else if (soa_serial != current_serial) {
	fail("IXFR out of sync: expected serial " +
	current_serial + " , got " + soa_serial);
	} else {
	state = IXFR_DELSOA;
	parseRR(rec); // Restart...
	return;
	}
	}
	handler.handleRecord(rec);
	break;

	case AXFR:
	// Old BINDs sent cross class A records for non IN classes.
	if (type == Type.A && rec.getDClass() != dclass)
	break;
	handler.handleRecord(rec);
	if (type == Type.SOA) {
	state = END;
	}
	break;

	case END:
	fail("extra data");
	break;

	default:
	fail("invalid state");
	break;
	}
	}

	private void
	closeConnection() {
	try {
	if (client != null)
	client.cleanup();
	}
	catch (IOException e) {
	}
	}

	private Message
	parseMessage(byte [] b) throws WireParseException {
	try {
	return new Message(b);
	}
	catch (IOException e) {
	if (e instanceof WireParseException)
	throw (WireParseException) e;
	throw new WireParseException("Error parsing message");
	}
	}

	private void
	doxfr() throws IOException, ZoneTransferException {
	sendQuery();
	while (state != END) {
	byte [] in = client.recv();
	Message response = parseMessage(in);
	if (response.getHeader().getRcode() == Rcode.NOERROR &&
	verifier != null)
	{
	TSIGRecord tsigrec = response.getTSIG();

	int error = verifier.verify(response, in);
	if (error != Rcode.NOERROR)
	fail("TSIG failure");
	}

	Record [] answers = response.getSectionArray(Section.ANSWER);

	if (state == INITIALSOA) {
	int rcode = response.getRcode();
	if (rcode != Rcode.NOERROR) {
	if (qtype == Type.IXFR &&
	rcode == Rcode.NOTIMP)
	{
	fallback();
	doxfr();
	return;
	}
	fail(Rcode.string(rcode));
	}

	Record question = response.getQuestion();
	if (question != null && question.getType() != qtype) {
	fail("invalid question section");
	}

	if (answers.length == 0 && qtype == Type.IXFR) {
	fallback();
	doxfr();
	return;
	}
	}

	for (int i = 0; i < answers.length; i++) {
	parseRR(answers[i]);
	}

	if (state == END && verifier != null &&
	!response.isVerified())
	fail("last message must be signed");
	}
	}

	/**
	* Does the zone transfer.
	* @param handler The callback object that handles the zone transfer data.
	* @throws IOException The zone transfer failed to due an IO problem.
	* @throws ZoneTransferException The zone transfer failed to due a problem
	* with the zone transfer itself.
	*/
	public void
	run(ZoneTransferHandler handler) throws IOException, ZoneTransferException {
	this.handler = handler;
	try {
	openConnection();
	doxfr();
	}
	finally {
	closeConnection();
	}
	}

	/**
	* Does the zone transfer.
	* @return A list, which is either an AXFR-style response (List of Records),
	* and IXFR-style response (List of Deltas), or null, which indicates that
	* an IXFR was performed and the zone is up to date.
	* @throws IOException The zone transfer failed to due an IO problem.
	* @throws ZoneTransferException The zone transfer failed to due a problem
	* with the zone transfer itself.
	*/
	public List
	run() throws IOException, ZoneTransferException {
	BasicHandler handler = new BasicHandler();
	run(handler);
	if (handler.axfr != null)
	return handler.axfr;
	return handler.ixfr;
	}

	private BasicHandler
	getBasicHandler() throws IllegalArgumentException {
	if (handler instanceof BasicHandler)
	return (BasicHandler) handler;
	throw new IllegalArgumentException("ZoneTransferIn used callback " +
	"interface");
	}

	/**
	* Returns true if the response is an AXFR-style response (List of Records).
	* This will be true if either an IXFR was performed, an IXFR was performed
	* and the server provided a full zone transfer, or an IXFR failed and
	* fallback to AXFR occurred.
	*/
	public boolean
	isAXFR() {
	return (rtype == Type.AXFR);
	}

	/**
	* Gets the AXFR-style response.
	* @throws IllegalArgumentException The transfer used the callback interface,
	* so the response was not stored.
	*/
	public List
	getAXFR() {
	BasicHandler handler = getBasicHandler();
	return handler.axfr;
	}

	/**
	* Returns true if the response is an IXFR-style response (List of Deltas).
	* This will be true only if an IXFR was performed and the server provided
	* an incremental zone transfer.
	*/
	public boolean
	isIXFR() {
	return (rtype == Type.IXFR);
	}

	/**
	* Gets the IXFR-style response.
	* @throws IllegalArgumentException The transfer used the callback interface,
	* so the response was not stored.
	*/
	public List
	getIXFR() {
	BasicHandler handler = getBasicHandler();
	return handler.ixfr;
	}

	/**
	* Returns true if the response indicates that the zone is up to date.
	* This will be true only if an IXFR was performed.
	* @throws IllegalArgumentException The transfer used the callback interface,
	* so the response was not stored.
	*/
	public boolean
	isCurrent() {
	BasicHandler handler = getBasicHandler();
	return (handler.axfr == null && handler.ixfr == null);
	}

	}