// Copyright 2003-2005 Arthur van Hoff, Rick Blair
// Licensed under Apache License version 2.0
// Original license LGPL
package javax.jmdns.impl;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.jmdns.impl.constants.DNSConstants;
import javax.jmdns.impl.constants.DNSRecordClass;
/**
* An outgoing DNS message.
*
* @author Arthur van Hoff, Rick Blair, Werner Randelshofer
*/
public final class DNSOutgoing extends DNSMessage {
public static class MessageOutputStream extends ByteArrayOutputStream {
private final DNSOutgoing _out;
private final int _offset;
/**
* Creates a new message stream, with a buffer capacity of the specified size, in bytes.
*
* @param size
* the initial size.
* @exception IllegalArgumentException
* if size is negative.
*/
MessageOutputStream(int size, DNSOutgoing out) {
this(size, out, 0);
}
MessageOutputStream(int size, DNSOutgoing out, int offset) {
super(size);
_out = out;
_offset = offset;
}
void writeByte(int value) {
this.write(value & 0xFF);
}
void writeBytes(String str, int off, int len) {
for (int i = 0; i < len; i++) {
writeByte(str.charAt(off + i));
}
}
void writeBytes(byte data[]) {
if (data != null) {
writeBytes(data, 0, data.length);
}
}
void writeBytes(byte data[], int off, int len) {
for (int i = 0; i < len; i++) {
writeByte(data[off + i]);
}
}
void writeShort(int value) {
writeByte(value >> 8);
writeByte(value);
}
void writeInt(int value) {
writeShort(value >> 16);
writeShort(value);
}
void writeUTF(String str, int off, int len) {
// compute utf length
int utflen = 0;
for (int i = 0; i < len; i++) {
int ch = str.charAt(off + i);
if ((ch >= 0x0001) && (ch <= 0x007F)) {
utflen += 1;
} else {
if (ch > 0x07FF) {
utflen += 3;
} else {
utflen += 2;
}
}
}
// write utf length
writeByte(utflen);
// write utf data
for (int i = 0; i < len; i++) {
int ch = str.charAt(off + i);
if ((ch >= 0x0001) && (ch <= 0x007F)) {
writeByte(ch);
} else {
if (ch > 0x07FF) {
writeByte(0xE0 | ((ch >> 12) & 0x0F));
writeByte(0x80 | ((ch >> 6) & 0x3F));
writeByte(0x80 | ((ch >> 0) & 0x3F));
} else {
writeByte(0xC0 | ((ch >> 6) & 0x1F));
writeByte(0x80 | ((ch >> 0) & 0x3F));
}
}
}
}
void writeName(String name) {
writeName(name, true);
}
void writeName(String name, boolean useCompression) {
String aName = name;
while (true) {
int n = aName.indexOf('.');
if (n < 0) {
n = aName.length();
}
if (n <= 0) {
writeByte(0);
return;
}
String label = aName.substring(0, n);
if (useCompression && USE_DOMAIN_NAME_COMPRESSION) {
Integer offset = _out._names.get(aName);
if (offset != null) {
int val = offset.intValue();
writeByte((val >> 8) | 0xC0);
writeByte(val & 0xFF);
return;
}
_out._names.put(aName, Integer.valueOf(this.size() + _offset));
writeUTF(label, 0, label.length());
} else {
writeUTF(label, 0, label.length());
}
aName = aName.substring(n);
if (aName.startsWith(".")) {
aName = aName.substring(1);
}
}
}
void writeQuestion(DNSQuestion question) {
writeName(question.getName());
writeShort(question.getRecordType().indexValue());
writeShort(question.getRecordClass().indexValue());
}
void writeRecord(DNSRecord rec, long now) {
writeName(rec.getName());
writeShort(rec.getRecordType().indexValue());
writeShort(rec.getRecordClass().indexValue() | ((rec.isUnique() && _out.isMulticast()) ? DNSRecordClass.CLASS_UNIQUE : 0));
writeInt((now == 0) ? rec.getTTL() : rec.getRemainingTTL(now));
// We need to take into account the 2 size bytes
MessageOutputStream record = new MessageOutputStream(512, _out, _offset + this.size() + 2);
rec.write(record);
byte[] byteArray = record.toByteArray();
writeShort(byteArray.length);
write(byteArray, 0, byteArray.length);
}
}
/**
* This can be used to turn off domain name compression. This was helpful for tracking problems interacting with other mdns implementations.
*/
public static boolean USE_DOMAIN_NAME_COMPRESSION = true;
Map<String, Integer> _names;
private int _maxUDPPayload;
private final MessageOutputStream _questionsBytes;
private final MessageOutputStream _answersBytes;
private final MessageOutputStream _authoritativeAnswersBytes;
private final MessageOutputStream _additionalsAnswersBytes;
private final static int HEADER_SIZE = 12;
/**
* Create an outgoing multicast query or response.
*
* @param flags
*/
public DNSOutgoing(int flags) {
this(flags, true, DNSConstants.MAX_MSG_TYPICAL);
}
/**
* Create an outgoing query or response.
*
* @param flags
* @param multicast
*/
public DNSOutgoing(int flags, boolean multicast) {
this(flags, multicast, DNSConstants.MAX_MSG_TYPICAL);
}
/**
* Create an outgoing query or response.
*
* @param flags
* @param multicast
* @param senderUDPPayload
* The sender's UDP payload size is the number of bytes of the largest UDP payload that can be reassembled and delivered in the sender's network stack.
*/
public DNSOutgoing(int flags, boolean multicast, int senderUDPPayload) {
super(flags, 0, multicast);
_names = new HashMap<String, Integer>();
_maxUDPPayload = (senderUDPPayload > 0 ? senderUDPPayload : DNSConstants.MAX_MSG_TYPICAL);
_questionsBytes = new MessageOutputStream(senderUDPPayload, this);
_answersBytes = new MessageOutputStream(senderUDPPayload, this);
_authoritativeAnswersBytes = new MessageOutputStream(senderUDPPayload, this);
_additionalsAnswersBytes = new MessageOutputStream(senderUDPPayload, this);
}
/**
* Return the number of byte available in the message.
*
* @return available space
*/
public int availableSpace() {
return _maxUDPPayload - HEADER_SIZE - _questionsBytes.size() - _answersBytes.size() - _authoritativeAnswersBytes.size() - _additionalsAnswersBytes.size();
}
/**
* Add a question to the message.
*
* @param rec
* @exception IOException
*/
public void addQuestion(DNSQuestion rec) throws IOException {
MessageOutputStream record = new MessageOutputStream(512, this);
record.writeQuestion(rec);
byte[] byteArray = record.toByteArray();
if (byteArray.length < this.availableSpace()) {
_questions.add(rec);
_questionsBytes.write(byteArray, 0, byteArray.length);
} else {
throw new IOException("message full");
}
}
/**
* Add an answer if it is not suppressed.
*
* @param in
* @param rec
* @exception IOException
*/
public void addAnswer(DNSIncoming in, DNSRecord rec) throws IOException {
if ((in == null) || !rec.suppressedBy(in)) {
this.addAnswer(rec, 0);
}
}
/**
* Add an answer to the message.
*
* @param rec
* @param now
* @exception IOException
*/
public void addAnswer(DNSRecord rec, long now) throws IOException {
if (rec != null) {
if ((now == 0) || !rec.isExpired(now)) {
MessageOutputStream record = new MessageOutputStream(512, this);
record.writeRecord(rec, now);
byte[] byteArray = record.toByteArray();
if (byteArray.length < this.availableSpace()) {
_answers.add(rec);
_answersBytes.write(byteArray, 0, byteArray.length);
} else {
throw new IOException("message full");
}
}
}
}
/**
* Add an authoritative answer to the message.
*
* @param rec
* @exception IOException
*/
public void addAuthorativeAnswer(DNSRecord rec) throws IOException {
MessageOutputStream record = new MessageOutputStream(512, this);
record.writeRecord(rec, 0);
byte[] byteArray = record.toByteArray();
if (byteArray.length < this.availableSpace()) {
_authoritativeAnswers.add(rec);
_authoritativeAnswersBytes.write(byteArray, 0, byteArray.length);
} else {
throw new IOException("message full");
}
}
/**
* Add an additional answer to the record. Omit if there is no room.
*
* @param in
* @param rec
* @exception IOException
*/
public void addAdditionalAnswer(DNSIncoming in, DNSRecord rec) throws IOException {
MessageOutputStream record = new MessageOutputStream(512, this);
record.writeRecord(rec, 0);
byte[] byteArray = record.toByteArray();
if (byteArray.length < this.availableSpace()) {
_additionals.add(rec);
_additionalsAnswersBytes.write(byteArray, 0, byteArray.length);
} else {
throw new IOException("message full");
}
}
/**
* Builds the final message buffer to be send and returns it.
*
* @return bytes to send.
*/
public byte[] data() {
long now = System.currentTimeMillis(); // System.currentTimeMillis()
_names.clear();
MessageOutputStream message = new MessageOutputStream(_maxUDPPayload, this);
message.writeShort(_multicast ? 0 : this.getId());
message.writeShort(this.getFlags());
message.writeShort(this.getNumberOfQuestions());
message.writeShort(this.getNumberOfAnswers());
message.writeShort(this.getNumberOfAuthorities());
message.writeShort(this.getNumberOfAdditionals());
for (DNSQuestion question : _questions) {
message.writeQuestion(question);
}
for (DNSRecord record : _answers) {
message.writeRecord(record, now);
}
for (DNSRecord record : _authoritativeAnswers) {
message.writeRecord(record, now);
}
for (DNSRecord record : _additionals) {
message.writeRecord(record, now);
}
return message.toByteArray();
}
@Override
public boolean isQuery() {
return (this.getFlags() & DNSConstants.FLAGS_QR_MASK) == DNSConstants.FLAGS_QR_QUERY;
}
/**
* Debugging.
*/
String print(boolean dump) {
StringBuilder buf = new StringBuilder();
buf.append(this.print());
if (dump) {
buf.append(this.print(this.data()));
}
return buf.toString();
}
@Override
public String toString() {
StringBuffer buf = new StringBuffer();
buf.append(isQuery() ? "dns[query:" : "dns[response:");
buf.append(" id=0x");
buf.append(Integer.toHexString(this.getId()));
if (this.getFlags() != 0) {
buf.append(", flags=0x");
buf.append(Integer.toHexString(this.getFlags()));
if ((this.getFlags() & DNSConstants.FLAGS_QR_RESPONSE) != 0) {
buf.append(":r");
}
if ((this.getFlags() & DNSConstants.FLAGS_AA) != 0) {
buf.append(":aa");
}
if ((this.getFlags() & DNSConstants.FLAGS_TC) != 0) {
buf.append(":tc");
}
}
if (this.getNumberOfQuestions() > 0) {
buf.append(", questions=");
buf.append(this.getNumberOfQuestions());
}
if (this.getNumberOfAnswers() > 0) {
buf.append(", answers=");
buf.append(this.getNumberOfAnswers());
}
if (this.getNumberOfAuthorities() > 0) {
buf.append(", authorities=");
buf.append(this.getNumberOfAuthorities());
}
if (this.getNumberOfAdditionals() > 0) {
buf.append(", additionals=");
buf.append(this.getNumberOfAdditionals());
}
if (this.getNumberOfQuestions() > 0) {
buf.append("\nquestions:");
for (DNSQuestion question : _questions) {
buf.append("\n\t");
buf.append(question);
}
}
if (this.getNumberOfAnswers() > 0) {
buf.append("\nanswers:");
for (DNSRecord record : _answers) {
buf.append("\n\t");
buf.append(record);
}
}
if (this.getNumberOfAuthorities() > 0) {
buf.append("\nauthorities:");
for (DNSRecord record : _authoritativeAnswers) {
buf.append("\n\t");
buf.append(record);
}
}
if (this.getNumberOfAdditionals() > 0) {
buf.append("\nadditionals:");
for (DNSRecord record : _additionals) {
buf.append("\n\t");
buf.append(record);
}
}
buf.append("\nnames=");
buf.append(_names);
buf.append("]");
return buf.toString();
}
/**
* @return the maxUDPPayload
*/
public int getMaxUDPPayload() {
return this._maxUDPPayload;
}
}