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

 // Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)

 package org.xbill.DNS;

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

 /**
  * A DNS Message.  A message is the basic unit of communication between
  * the client and server of a DNS operation.  A message consists of a Header
  * and 4 message sections.
  * @see Resolver
  * @see Header
  * @see Section
  *
  * @author Brian Wellington
  */

 public class Message implements Cloneable {

 /** The maximum length of a message in wire format. */
 public static final int MAXLENGTH = 65535;

 private Header header;
 private List [] sections;
 private int size;
 private TSIG tsigkey;
 private TSIGRecord querytsig;
 private int tsigerror;

 int tsigstart;
 int tsigState;
 int sig0start;

 /* The message was not signed */
 static final int TSIG_UNSIGNED = 0;

 /* The message was signed and verification succeeded */
 static final int TSIG_VERIFIED = 1;

 /* The message was an unsigned message in multiple-message response */
 static final int TSIG_INTERMEDIATE = 2;

 /* The message was signed and no verification was attempted.  */
 static final int TSIG_SIGNED = 3;

 /*
  * The message was signed and verification failed, or was not signed
  * when it should have been.
  */
 static final int TSIG_FAILED = 4;

 private static Record [] emptyRecordArray = new Record[0];
 private static RRset [] emptyRRsetArray = new RRset[0];

 private
 Message(Header header) {
 	sections = new List[4];
 	this.header = header;
 }

 /** Creates a new Message with the specified Message ID */
 public
 Message(int id) {
 	this(new Header(id));
 }

 /** Creates a new Message with a random Message ID */
 public
 Message() {
 	this(new Header());
 }

 /**
  * Creates a new Message with a random Message ID suitable for sending as a
  * query.
  * @param r A record containing the question
  */
 public static Message
 newQuery(Record r) {
 	Message m = new Message();
 	m.header.setOpcode(Opcode.QUERY);
 	m.header.setFlag(Flags.RD);
 	m.addRecord(r, Section.QUESTION);
 	return m;
 }

 /**
  * Creates a new Message to contain a dynamic update.  A random Message ID
  * and the zone are filled in.
  * @param zone The zone to be updated
  */
 public static Message
 newUpdate(Name zone) {
 	return new Update(zone);
 }

 Message(DNSInput in) throws IOException {
 	this(new Header(in));
 	boolean isUpdate = (header.getOpcode() == Opcode.UPDATE);
 	boolean truncated = header.getFlag(Flags.TC);
 	try {
 		for (int i = 0; i < 4; i++) {
 			int count = header.getCount(i);
 			if (count > 0)
 				sections[i] = new ArrayList(count);
 			for (int j = 0; j < count; j++) {
 				int pos = in.current();
 				Record rec = Record.fromWire(in, i, isUpdate);
 				sections[i].add(rec);
 				if (i == Section.ADDITIONAL) {
 					if (rec.getType() == Type.TSIG)
 						tsigstart = pos;
 					if (rec.getType() == Type.SIG) {
 						SIGRecord sig = (SIGRecord) rec;
 						if (sig.getTypeCovered() == 0)
 							sig0start = pos;
 					}
 				}
 			}
 		}
 	} catch (WireParseException e) {
 		if (!truncated)
 			throw e;
 	}
 	size = in.current();
 }

 /**
  * Creates a new Message from its DNS wire format representation
  * @param b A byte array containing the DNS Message.
  */
 public
 Message(byte [] b) throws IOException {
 	this(new DNSInput(b));
 }

 /**
  * Replaces the Header with a new one.
  * @see Header
  */
 public void
 setHeader(Header h) {
 	header = h;
 }

 /**
  * Retrieves the Header.
  * @see Header
  */
 public Header
 getHeader() {
 	return header;
 }

 /**
  * Adds a record to a section of the Message, and adjusts the header.
  * @see Record
  * @see Section
  */
 public void
 addRecord(Record r, int section) {
 	if (sections[section] == null)
 		sections[section] = new LinkedList();
 	header.incCount(section);
 	sections[section].add(r);
 }

 /**
  * Removes a record from a section of the Message, and adjusts the header.
  * @see Record
  * @see Section
  */
 public boolean
 removeRecord(Record r, int section) {
 	if (sections[section] != null && sections[section].remove(r)) {
 		header.decCount(section);
 		return true;
 	}
 	else
 		return false;
 }

 /**
  * Removes all records from a section of the Message, and adjusts the header.
  * @see Record
  * @see Section
  */
 public void
 removeAllRecords(int section) {
 	sections[section] = null;
 	header.setCount(section, 0);
 }

 /**
  * Determines if the given record is already present in the given section.
  * @see Record
  * @see Section
  */
 public boolean
 findRecord(Record r, int section) {
 	return (sections[section] != null && sections[section].contains(r));
 }

 /**
  * Determines if the given record is already present in any section.
  * @see Record
  * @see Section
  */
 public boolean
 findRecord(Record r) {
 	for (int i = Section.ANSWER; i <= Section.ADDITIONAL; i++)
 		if (sections[i] != null && sections[i].contains(r))
 			return true;
 	return false;
 }

 /**
  * Determines if an RRset with the given name and type is already
  * present in the given section.
  * @see RRset
  * @see Section
  */
 public boolean
 findRRset(Name name, int type, int section) {
 	if (sections[section] == null)
 		return false;
 	for (int i = 0; i < sections[section].size(); i++) {
 		Record r = (Record) sections[section].get(i);
 		if (r.getType() == type && name.equals(r.getName()))
 			return true;
 	}
 	return false;
 }

 /**
  * Determines if an RRset with the given name and type is already
  * present in any section.
  * @see RRset
  * @see Section
  */
 public boolean
 findRRset(Name name, int type) {
 	return (findRRset(name, type, Section.ANSWER) ||
 		findRRset(name, type, Section.AUTHORITY) ||
 		findRRset(name, type, Section.ADDITIONAL));
 }

 /**
  * Returns the first record in the QUESTION section.
  * @see Record
  * @see Section
  */
 public Record
 getQuestion() {
 	List l = sections[Section.QUESTION];
 	if (l == null || l.size() == 0)
 		return null;
 	return (Record) l.get(0);
 }

 /**
  * Returns the TSIG record from the ADDITIONAL section, if one is present.
  * @see TSIGRecord
  * @see TSIG
  * @see Section
  */
 public TSIGRecord
 getTSIG() {
 	int count = header.getCount(Section.ADDITIONAL);
 	if (count == 0)
 		return null;
 	List l = sections[Section.ADDITIONAL];
 	Record rec = (Record) l.get(count - 1);
 	if (rec.type !=  Type.TSIG)
 		return null;
 	return (TSIGRecord) rec;
 }

 /**
  * Was this message signed by a TSIG?
  * @see TSIG
  */
 public boolean
 isSigned() {
 	return (tsigState == TSIG_SIGNED ||
 		tsigState == TSIG_VERIFIED ||
 		tsigState == TSIG_FAILED);
 }

 /**
  * If this message was signed by a TSIG, was the TSIG verified?
  * @see TSIG
  */
 public boolean
 isVerified() {
 	return (tsigState == TSIG_VERIFIED);
 }

 /**
  * Returns the OPT record from the ADDITIONAL section, if one is present.
  * @see OPTRecord
  * @see Section
  */
 public OPTRecord
 getOPT() {
 	Record [] additional = getSectionArray(Section.ADDITIONAL);
 	for (int i = 0; i < additional.length; i++)
 		if (additional[i] instanceof OPTRecord)
 			return (OPTRecord) additional[i];
 	return null;
 }

 /**
  * Returns the message's rcode (error code).  This incorporates the EDNS
  * extended rcode.
  */
 public int
 getRcode() {
 	int rcode = header.getRcode();
 	OPTRecord opt = getOPT();
 	if (opt != null)
 		rcode += (opt.getExtendedRcode() << 4);
 	return rcode;
 }

 /**
  * Returns an array containing all records in the given section, or an
  * empty array if the section is empty.
  * @see Record
  * @see Section
  */
 public Record []
 getSectionArray(int section) {
 	if (sections[section] == null)
 		return emptyRecordArray;
 	List l = sections[section];
 	return (Record []) l.toArray(new Record[l.size()]);
 }

 private static boolean
 sameSet(Record r1, Record r2) {
 	return (r1.getRRsetType() == r2.getRRsetType() &&
 		r1.getDClass() == r2.getDClass() &&
 		r1.getName().equals(r2.getName()));
 }

 /**
  * Returns an array containing all records in the given section grouped into
  * RRsets.
  * @see RRset
  * @see Section
  */
 public RRset []
 getSectionRRsets(int section) {
 	if (sections[section] == null)
 		return emptyRRsetArray;
 	List sets = new LinkedList();
 	Record [] recs = getSectionArray(section);
 	Set hash = new HashSet();
 	for (int i = 0; i < recs.length; i++) {
 		Name name = recs[i].getName();
 		boolean newset = true;
 		if (hash.contains(name)) {
 			for (int j = sets.size() - 1; j >= 0; j--) {
 				RRset set = (RRset) sets.get(j);
 				if (set.getType() == recs[i].getRRsetType() &&
 				    set.getDClass() == recs[i].getDClass() &&
 				    set.getName().equals(name))
 				{
 					set.addRR(recs[i]);
 					newset = false;
 					break;
 				}
 			}
 		}
 		if (newset) {
 			RRset set = new RRset(recs[i]);
 			sets.add(set);
 			hash.add(name);
 		}
 	}
 	return (RRset []) sets.toArray(new RRset[sets.size()]);
 }

 void
 toWire(DNSOutput out) {
 	header.toWire(out);
 	Compression c = new Compression();
 	for (int i = 0; i < 4; i++) {
 		if (sections[i] == null)
 			continue;
 		for (int j = 0; j < sections[i].size(); j++) {
 			Record rec = (Record)sections[i].get(j);
 			rec.toWire(out, i, c);
 		}
 	}
 }

 /* Returns the number of records not successfully rendered. */
 private int
 sectionToWire(DNSOutput out, int section, Compression c,
 	      int maxLength)
 {
 	int n = sections[section].size();
 	int pos = out.current();
 	int rendered = 0;
 	Record lastrec = null;

 	for (int i = 0; i < n; i++) {
 		Record rec = (Record)sections[section].get(i);
 		if (lastrec != null && !sameSet(rec, lastrec)) {
 			pos = out.current();
 			rendered = i;
 		}
 		lastrec = rec;
 		rec.toWire(out, section, c);
 		if (out.current() > maxLength) {
 			out.jump(pos);
 			return n - rendered;
 		}
 	}
 	return 0;
 }

 /* Returns true if the message could be rendered. */
 private boolean
 toWire(DNSOutput out, int maxLength) {
 	if (maxLength < Header.LENGTH)
 		return false;

 	Header newheader = null;

 	int tempMaxLength = maxLength;
 	if (tsigkey != null)
 		tempMaxLength -= tsigkey.recordLength();

 	int startpos = out.current();
 	header.toWire(out);
 	Compression c = new Compression();
 	for (int i = 0; i < 4; i++) {
 		int skipped;
 		if (sections[i] == null)
 			continue;
 		skipped = sectionToWire(out, i, c, tempMaxLength);
 		if (skipped != 0) {
 			if (newheader == null)
 				newheader = (Header) header.clone();
 			if (i != Section.ADDITIONAL)
 				newheader.setFlag(Flags.TC);
 			int count = newheader.getCount(i);
 			newheader.setCount(i, count - skipped);
 			for (int j = i + 1; j < 4; j++)
 				newheader.setCount(j, 0);

 			out.save();
 			out.jump(startpos);
 			newheader.toWire(out);
 			out.restore();
 			break;
 		}
 	}

 	if (tsigkey != null) {
 		TSIGRecord tsigrec = tsigkey.generate(this, out.toByteArray(),
 						      tsigerror, querytsig);

 		if (newheader == null)
 			newheader = (Header) header.clone();
 		tsigrec.toWire(out, Section.ADDITIONAL, c);
 		newheader.incCount(Section.ADDITIONAL);

 		out.save();
 		out.jump(startpos);
 		newheader.toWire(out);
 		out.restore();
 	}

 	return true;
 }

 /**
  * Returns an array containing the wire format representation of the Message.
  */
 public byte []
 toWire() {
 	DNSOutput out = new DNSOutput();
 	toWire(out);
 	size = out.current();
 	return out.toByteArray();
 }

 /**
  * Returns an array containing the wire format representation of the Message
  * with the specified maximum length.  This will generate a truncated
  * message (with the TC bit) if the message doesn't fit, and will also
  * sign the message with the TSIG key set by a call to setTSIG().  This
  * method may return null if the message could not be rendered at all; this
  * could happen if maxLength is smaller than a DNS header, for example.
  * @param maxLength The maximum length of the message.
  * @return The wire format of the message, or null if the message could not be
  * rendered into the specified length.
  * @see Flags
  * @see TSIG
  */
 public byte []
 toWire(int maxLength) {
 	DNSOutput out = new DNSOutput();
 	toWire(out, maxLength);
 	size = out.current();
 	return out.toByteArray();
 }

 /**
  * Sets the TSIG key and other necessary information to sign a message.
  * @param key The TSIG key.
  * @param error The value of the TSIG error field.
  * @param querytsig If this is a response, the TSIG from the request.
  */
 public void
 setTSIG(TSIG key, int error, TSIGRecord querytsig) {
 	this.tsigkey = key;
 	this.tsigerror = error;
 	this.querytsig = querytsig;
 }

 /**
  * Returns the size of the message.  Only valid if the message has been
  * converted to or from wire format.
  */
 public int
 numBytes() {
 	return size;
 }

 /**
  * Converts the given section of the Message to a String.
  * @see Section
  */
 public String
 sectionToString(int i) {
 	if (i > 3)
 		return null;

 	StringBuffer sb = new StringBuffer();

 	Record [] records = getSectionArray(i);
 	for (int j = 0; j < records.length; j++) {
 		Record rec = records[j];
 		if (i == Section.QUESTION) {
 			sb.append(";;\t" + rec.name);
 			sb.append(", type = " + Type.string(rec.type));
 			sb.append(", class = " + DClass.string(rec.dclass));
 		}
 		else
 			sb.append(rec);
 		sb.append("\n");
 	}
 	return sb.toString();
 }

 /**
  * Converts the Message to a String.
  */
 public String
 toString() {
 	StringBuffer sb = new StringBuffer();
 	OPTRecord opt = getOPT();
 	if (opt != null)
 		sb.append(header.toStringWithRcode(getRcode()) + "\n");
 	else
 		sb.append(header + "\n");
 	if (isSigned()) {
 		sb.append(";; TSIG ");
 		if (isVerified())
 			sb.append("ok");
 		else
 			sb.append("invalid");
 		sb.append('\n');
 	}
 	for (int i = 0; i < 4; i++) {
 		if (header.getOpcode() != Opcode.UPDATE)
 			sb.append(";; " + Section.longString(i) + ":\n");
 		else
 			sb.append(";; " + Section.updString(i) + ":\n");
 		sb.append(sectionToString(i) + "\n");
 	}
 	sb.append(";; Message size: " + numBytes() + " bytes");
 	return sb.toString();
 }

 /**
  * Creates a copy of this Message.  This is done by the Resolver before adding
  * TSIG and OPT records, for example.
  * @see Resolver
  * @see TSIGRecord
  * @see OPTRecord
  */
 public Object
 clone() {
 	Message m = new Message();
 	for (int i = 0; i < sections.length; i++) {
 		if (sections[i] != null)
 			m.sections[i] = new LinkedList(sections[i]);
 	}
 	m.header = (Header) header.clone();
 	m.size = size;
 	return m;
 }

 }
	// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)

	package org.xbill.DNS;

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

	/**
	* A DNS Message. A message is the basic unit of communication between
	* the client and server of a DNS operation. A message consists of a Header
	* and 4 message sections.
	* @see Resolver
	* @see Header
	* @see Section
	*
	* @author Brian Wellington
	*/

	public class Message implements Cloneable {

	/** The maximum length of a message in wire format. */
	public static final int MAXLENGTH = 65535;

	private Header header;
	private List [] sections;
	private int size;
	private TSIG tsigkey;
	private TSIGRecord querytsig;
	private int tsigerror;

	int tsigstart;
	int tsigState;
	int sig0start;

	/* The message was not signed */
	static final int TSIG_UNSIGNED = 0;

	/* The message was signed and verification succeeded */
	static final int TSIG_VERIFIED = 1;

	/* The message was an unsigned message in multiple-message response */
	static final int TSIG_INTERMEDIATE = 2;

	/* The message was signed and no verification was attempted. */
	static final int TSIG_SIGNED = 3;

	/*
	* The message was signed and verification failed, or was not signed
	* when it should have been.
	*/
	static final int TSIG_FAILED = 4;

	private static Record [] emptyRecordArray = new Record[0];
	private static RRset [] emptyRRsetArray = new RRset[0];

	private
	Message(Header header) {
	sections = new List[4];
	this.header = header;
	}

	/** Creates a new Message with the specified Message ID */
	public
	Message(int id) {
	this(new Header(id));
	}

	/** Creates a new Message with a random Message ID */
	public
	Message() {
	this(new Header());
	}

	/**
	* Creates a new Message with a random Message ID suitable for sending as a
	* query.
	* @param r A record containing the question
	*/
	public static Message
	newQuery(Record r) {
	Message m = new Message();
	m.header.setOpcode(Opcode.QUERY);
	m.header.setFlag(Flags.RD);
	m.addRecord(r, Section.QUESTION);
	return m;
	}

	/**
	* Creates a new Message to contain a dynamic update. A random Message ID
	* and the zone are filled in.
	* @param zone The zone to be updated
	*/
	public static Message
	newUpdate(Name zone) {
	return new Update(zone);
	}

	Message(DNSInput in) throws IOException {
	this(new Header(in));
	boolean isUpdate = (header.getOpcode() == Opcode.UPDATE);
	boolean truncated = header.getFlag(Flags.TC);
	try {
	for (int i = 0; i < 4; i++) {
	int count = header.getCount(i);
	if (count > 0)
	sections[i] = new ArrayList(count);
	for (int j = 0; j < count; j++) {
	int pos = in.current();
	Record rec = Record.fromWire(in, i, isUpdate);
	sections[i].add(rec);
	if (i == Section.ADDITIONAL) {
	if (rec.getType() == Type.TSIG)
	tsigstart = pos;
	if (rec.getType() == Type.SIG) {
	SIGRecord sig = (SIGRecord) rec;
	if (sig.getTypeCovered() == 0)
	sig0start = pos;
	}
	}
	}
	}
	} catch (WireParseException e) {
	if (!truncated)
	throw e;
	}
	size = in.current();
	}

	/**
	* Creates a new Message from its DNS wire format representation
	* @param b A byte array containing the DNS Message.
	*/
	public
	Message(byte [] b) throws IOException {
	this(new DNSInput(b));
	}

	/**
	* Replaces the Header with a new one.
	* @see Header
	*/
	public void
	setHeader(Header h) {
	header = h;
	}

	/**
	* Retrieves the Header.
	* @see Header
	*/
	public Header
	getHeader() {
	return header;
	}

	/**
	* Adds a record to a section of the Message, and adjusts the header.
	* @see Record
	* @see Section
	*/
	public void
	addRecord(Record r, int section) {
	if (sections[section] == null)
	sections[section] = new LinkedList();
	header.incCount(section);
	sections[section].add(r);
	}

	/**
	* Removes a record from a section of the Message, and adjusts the header.
	* @see Record
	* @see Section
	*/
	public boolean
	removeRecord(Record r, int section) {
	if (sections[section] != null && sections[section].remove(r)) {
	header.decCount(section);
	return true;
	}
	else
	return false;
	}

	/**
	* Removes all records from a section of the Message, and adjusts the header.
	* @see Record
	* @see Section
	*/
	public void
	removeAllRecords(int section) {
	sections[section] = null;
	header.setCount(section, 0);
	}

	/**
	* Determines if the given record is already present in the given section.
	* @see Record
	* @see Section
	*/
	public boolean
	findRecord(Record r, int section) {
	return (sections[section] != null && sections[section].contains(r));
	}

	/**
	* Determines if the given record is already present in any section.
	* @see Record
	* @see Section
	*/
	public boolean
	findRecord(Record r) {
	for (int i = Section.ANSWER; i <= Section.ADDITIONAL; i++)
	if (sections[i] != null && sections[i].contains(r))
	return true;
	return false;
	}

	/**
	* Determines if an RRset with the given name and type is already
	* present in the given section.
	* @see RRset
	* @see Section
	*/
	public boolean
	findRRset(Name name, int type, int section) {
	if (sections[section] == null)
	return false;
	for (int i = 0; i < sections[section].size(); i++) {
	Record r = (Record) sections[section].get(i);
	if (r.getType() == type && name.equals(r.getName()))
	return true;
	}
	return false;
	}

	/**
	* Determines if an RRset with the given name and type is already
	* present in any section.
	* @see RRset
	* @see Section
	*/
	public boolean
	findRRset(Name name, int type) {
	return (findRRset(name, type, Section.ANSWER) \|\|
	findRRset(name, type, Section.AUTHORITY) \|\|
	findRRset(name, type, Section.ADDITIONAL));
	}

	/**
	* Returns the first record in the QUESTION section.
	* @see Record
	* @see Section
	*/
	public Record
	getQuestion() {
	List l = sections[Section.QUESTION];
	if (l == null \|\| l.size() == 0)
	return null;
	return (Record) l.get(0);
	}

	/**
	* Returns the TSIG record from the ADDITIONAL section, if one is present.
	* @see TSIGRecord
	* @see TSIG
	* @see Section
	*/
	public TSIGRecord
	getTSIG() {
	int count = header.getCount(Section.ADDITIONAL);
	if (count == 0)
	return null;
	List l = sections[Section.ADDITIONAL];
	Record rec = (Record) l.get(count - 1);
	if (rec.type != Type.TSIG)
	return null;
	return (TSIGRecord) rec;
	}

	/**
	* Was this message signed by a TSIG?
	* @see TSIG
	*/
	public boolean
	isSigned() {
	return (tsigState == TSIG_SIGNED \|\|
	tsigState == TSIG_VERIFIED \|\|
	tsigState == TSIG_FAILED);
	}

	/**
	* If this message was signed by a TSIG, was the TSIG verified?
	* @see TSIG
	*/
	public boolean
	isVerified() {
	return (tsigState == TSIG_VERIFIED);
	}

	/**
	* Returns the OPT record from the ADDITIONAL section, if one is present.
	* @see OPTRecord
	* @see Section
	*/
	public OPTRecord
	getOPT() {
	Record [] additional = getSectionArray(Section.ADDITIONAL);
	for (int i = 0; i < additional.length; i++)
	if (additional[i] instanceof OPTRecord)
	return (OPTRecord) additional[i];
	return null;
	}

	/**
	* Returns the message's rcode (error code). This incorporates the EDNS
	* extended rcode.
	*/
	public int
	getRcode() {
	int rcode = header.getRcode();
	OPTRecord opt = getOPT();
	if (opt != null)
	rcode += (opt.getExtendedRcode() << 4);
	return rcode;
	}

	/**
	* Returns an array containing all records in the given section, or an
	* empty array if the section is empty.
	* @see Record
	* @see Section
	*/
	public Record []
	getSectionArray(int section) {
	if (sections[section] == null)
	return emptyRecordArray;
	List l = sections[section];
	return (Record []) l.toArray(new Record[l.size()]);
	}

	private static boolean
	sameSet(Record r1, Record r2) {
	return (r1.getRRsetType() == r2.getRRsetType() &&
	r1.getDClass() == r2.getDClass() &&
	r1.getName().equals(r2.getName()));
	}

	/**
	* Returns an array containing all records in the given section grouped into
	* RRsets.
	* @see RRset
	* @see Section
	*/
	public RRset []
	getSectionRRsets(int section) {
	if (sections[section] == null)
	return emptyRRsetArray;
	List sets = new LinkedList();
	Record [] recs = getSectionArray(section);
	Set hash = new HashSet();
	for (int i = 0; i < recs.length; i++) {
	Name name = recs[i].getName();
	boolean newset = true;
	if (hash.contains(name)) {
	for (int j = sets.size() - 1; j >= 0; j--) {
	RRset set = (RRset) sets.get(j);
	if (set.getType() == recs[i].getRRsetType() &&
	set.getDClass() == recs[i].getDClass() &&
	set.getName().equals(name))
	{
	set.addRR(recs[i]);
	newset = false;
	break;
	}
	}
	}
	if (newset) {
	RRset set = new RRset(recs[i]);
	sets.add(set);
	hash.add(name);
	}
	}
	return (RRset []) sets.toArray(new RRset[sets.size()]);
	}

	void
	toWire(DNSOutput out) {
	header.toWire(out);
	Compression c = new Compression();
	for (int i = 0; i < 4; i++) {
	if (sections[i] == null)
	continue;
	for (int j = 0; j < sections[i].size(); j++) {
	Record rec = (Record)sections[i].get(j);
	rec.toWire(out, i, c);
	}
	}
	}

	/* Returns the number of records not successfully rendered. */
	private int
	sectionToWire(DNSOutput out, int section, Compression c,
	int maxLength)
	{
	int n = sections[section].size();
	int pos = out.current();
	int rendered = 0;
	Record lastrec = null;

	for (int i = 0; i < n; i++) {
	Record rec = (Record)sections[section].get(i);
	if (lastrec != null && !sameSet(rec, lastrec)) {
	pos = out.current();
	rendered = i;
	}
	lastrec = rec;
	rec.toWire(out, section, c);
	if (out.current() > maxLength) {
	out.jump(pos);
	return n - rendered;
	}
	}
	return 0;
	}

	/* Returns true if the message could be rendered. */
	private boolean
	toWire(DNSOutput out, int maxLength) {
	if (maxLength < Header.LENGTH)
	return false;

	Header newheader = null;

	int tempMaxLength = maxLength;
	if (tsigkey != null)
	tempMaxLength -= tsigkey.recordLength();

	int startpos = out.current();
	header.toWire(out);
	Compression c = new Compression();
	for (int i = 0; i < 4; i++) {
	int skipped;
	if (sections[i] == null)
	continue;
	skipped = sectionToWire(out, i, c, tempMaxLength);
	if (skipped != 0) {
	if (newheader == null)
	newheader = (Header) header.clone();
	if (i != Section.ADDITIONAL)
	newheader.setFlag(Flags.TC);
	int count = newheader.getCount(i);
	newheader.setCount(i, count - skipped);
	for (int j = i + 1; j < 4; j++)
	newheader.setCount(j, 0);

	out.save();
	out.jump(startpos);
	newheader.toWire(out);
	out.restore();
	break;
	}
	}

	if (tsigkey != null) {
	TSIGRecord tsigrec = tsigkey.generate(this, out.toByteArray(),
	tsigerror, querytsig);

	if (newheader == null)
	newheader = (Header) header.clone();
	tsigrec.toWire(out, Section.ADDITIONAL, c);
	newheader.incCount(Section.ADDITIONAL);

	out.save();
	out.jump(startpos);
	newheader.toWire(out);
	out.restore();
	}

	return true;
	}

	/**
	* Returns an array containing the wire format representation of the Message.
	*/
	public byte []
	toWire() {
	DNSOutput out = new DNSOutput();
	toWire(out);
	size = out.current();
	return out.toByteArray();
	}

	/**
	* Returns an array containing the wire format representation of the Message
	* with the specified maximum length. This will generate a truncated
	* message (with the TC bit) if the message doesn't fit, and will also
	* sign the message with the TSIG key set by a call to setTSIG(). This
	* method may return null if the message could not be rendered at all; this
	* could happen if maxLength is smaller than a DNS header, for example.
	* @param maxLength The maximum length of the message.
	* @return The wire format of the message, or null if the message could not be
	* rendered into the specified length.
	* @see Flags
	* @see TSIG
	*/
	public byte []
	toWire(int maxLength) {
	DNSOutput out = new DNSOutput();
	toWire(out, maxLength);
	size = out.current();
	return out.toByteArray();
	}

	/**
	* Sets the TSIG key and other necessary information to sign a message.
	* @param key The TSIG key.
	* @param error The value of the TSIG error field.
	* @param querytsig If this is a response, the TSIG from the request.
	*/
	public void
	setTSIG(TSIG key, int error, TSIGRecord querytsig) {
	this.tsigkey = key;
	this.tsigerror = error;
	this.querytsig = querytsig;
	}

	/**
	* Returns the size of the message. Only valid if the message has been
	* converted to or from wire format.
	*/
	public int
	numBytes() {
	return size;
	}

	/**
	* Converts the given section of the Message to a String.
	* @see Section
	*/
	public String
	sectionToString(int i) {
	if (i > 3)
	return null;

	StringBuffer sb = new StringBuffer();

	Record [] records = getSectionArray(i);
	for (int j = 0; j < records.length; j++) {
	Record rec = records[j];
	if (i == Section.QUESTION) {
	sb.append(";;\t" + rec.name);
	sb.append(", type = " + Type.string(rec.type));
	sb.append(", class = " + DClass.string(rec.dclass));
	}
	else
	sb.append(rec);
	sb.append("\n");
	}
	return sb.toString();
	}

	/**
	* Converts the Message to a String.
	*/
	public String
	toString() {
	StringBuffer sb = new StringBuffer();
	OPTRecord opt = getOPT();
	if (opt != null)
	sb.append(header.toStringWithRcode(getRcode()) + "\n");
	else
	sb.append(header + "\n");
	if (isSigned()) {
	sb.append(";; TSIG ");
	if (isVerified())
	sb.append("ok");
	else
	sb.append("invalid");
	sb.append('\n');
	}
	for (int i = 0; i < 4; i++) {
	if (header.getOpcode() != Opcode.UPDATE)
	sb.append(";; " + Section.longString(i) + ":\n");
	else
	sb.append(";; " + Section.updString(i) + ":\n");
	sb.append(sectionToString(i) + "\n");
	}
	sb.append(";; Message size: " + numBytes() + " bytes");
	return sb.toString();
	}

	/**
	* Creates a copy of this Message. This is done by the Resolver before adding
	* TSIG and OPT records, for example.
	* @see Resolver
	* @see TSIGRecord
	* @see OPTRecord
	*/
	public Object
	clone() {
	Message m = new Message();
	for (int i = 0; i < sections.length; i++) {
	if (sections[i] != null)
	m.sections[i] = new LinkedList(sections[i]);
	}
	m.header = (Header) header.clone();
	m.size = size;
	return m;
	}

	}