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Minimal DNS library for java and android systems
/*
* Copyright 2015-2016 the original author or authors
*
* This software is licensed under the Apache License, Version 2.0,
* the GNU Lesser General Public License version 2 or later ("LGPL")
* and the WTFPL.
* You may choose either license to govern your use of this software only
* upon the condition that you accept all of the terms of either
* the Apache License 2.0, the LGPL 2.1+ or the WTFPL.
*/
package de.measite.minidns;
import de.measite.minidns.Record.TYPE;
import de.measite.minidns.record.Data;
import de.measite.minidns.record.OPT;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* A DNS message as defined by RFC 1035. The message consists of a header and
* 4 sections: question, answer, nameserver and addition resource record
* section.
* A message can either be parsed ({@link #DNSMessage(byte[])}) or serialized
* ({@link DNSMessage#toArray()}).
*
* @see RFC 1035
*/
public class DNSMessage {
private static final Logger LOGGER = Logger.getLogger(DNSMessage.class.getName());
/**
* Possible DNS response codes.
*
* @see
* IANA Domain Name System (DNS) Paramters - DNS RCODEs
* @see RFC 6895 § 2.3
*/
public static enum RESPONSE_CODE {
NO_ERROR(0),
FORMAT_ERR(1),
SERVER_FAIL(2),
NX_DOMAIN(3),
NO_IMP(4),
REFUSED(5),
YXDOMAIN(6),
YXRRSET(7),
NXRRSET(8),
NOT_AUTH(9),
NOT_ZONE(10),
BADVERS_BADSIG(16),
BADKEY(17),
BADTIME(18),
BADMODE(19),
BADNAME(20),
BADALG(21),
BADTRUNC(22),
BADCOOKIE(23),
;
/**
* Reverse lookup table for response codes.
*/
private final static Map INVERSE_LUT = new HashMap<>(RESPONSE_CODE.values().length);
static {
for (RESPONSE_CODE responseCode : RESPONSE_CODE.values()) {
INVERSE_LUT.put((int) responseCode.value, responseCode);
}
}
/**
* The response code value.
*/
private final byte value;
/**
* Create a new response code.
*
* @param value The response code value.
*/
private RESPONSE_CODE(int value) {
this.value = (byte) value;
}
/**
* Retrieve the byte value of the response code.
*
* @return the response code.
*/
public byte getValue() {
return value;
}
/**
* Retrieve the response code for a byte value.
*
* @param value The byte value.
* @return The symbolic response code or null.
* @throws IllegalArgumentException if the value is not in the range of 0..15.
*/
public static RESPONSE_CODE getResponseCode(int value) throws IllegalArgumentException {
if (value < 0 || value > 65535) {
throw new IllegalArgumentException();
}
return INVERSE_LUT.get(value);
}
}
/**
* Symbolic DNS Opcode values.
*
* @see
* IANA Domain Name System (DNS) Paramters - DNS OpCodes
*/
public static enum OPCODE {
QUERY,
INVERSE_QUERY,
STATUS,
UNASSIGNED3,
NOTIFY,
UPDATE,
;
/**
* Lookup table for for opcode resolution.
*/
private final static OPCODE INVERSE_LUT[] = new OPCODE[OPCODE.values().length];
static {
for (OPCODE opcode : OPCODE.values()) {
if (INVERSE_LUT[opcode.getValue()] != null) {
throw new IllegalStateException();
}
INVERSE_LUT[opcode.getValue()] = opcode;
}
}
/**
* The value of this opcode.
*/
private final byte value;
/**
* Create a new opcode for a given byte value.
*
*/
private OPCODE() {
this.value = (byte) this.ordinal();
}
/**
* Retrieve the byte value of this opcode.
*
* @return The byte value of this opcode.
*/
public byte getValue() {
return value;
}
/**
* Retrieve the symbolic name of an opcode byte.
*
* @param value The byte value of the opcode.
* @return The symbolic opcode or null.
* @throws IllegalArgumentException If the byte value is not in the
* range 0..15.
*/
public static OPCODE getOpcode(int value) throws IllegalArgumentException {
if (value < 0 || value > 15) {
throw new IllegalArgumentException();
}
if (value >= INVERSE_LUT.length) {
return null;
}
return INVERSE_LUT[value];
}
}
/**
* The DNS message id.
*/
public final int id;
/**
* The DNS message opcode.
*/
public final OPCODE opcode;
/**
* The response code of this dns message.
*/
public final RESPONSE_CODE responseCode;
/**
* The QR flag of the DNS message header. Note that this will be true if the message is a
* response and false if it is a query.
*
* @see RFC 1035 § 4.1.1
*/
public final boolean qr;
/**
* True if this is a authorative response.
*/
public final boolean authoritativeAnswer;
/**
* True if message is truncated. Then TCP should be used.
*/
public final boolean truncated;
/**
* True if the server should recurse.
*/
public final boolean recursionDesired;
/**
* True if recursion is possible.
*/
public final boolean recursionAvailable;
/**
* True if the server regarded the response as authentic.
*/
public final boolean authenticData;
/**
* True if the server should not perform DNSSEC validation before returning the result.
*/
public final boolean checkingDisabled;
/**
* The question section content. Usually there will be only one question.
*
* This list is unmodifiable.
*
*/
public final List questions;
/**
* The answers section records. Note that it is not guaranteed that all records found in this section will be direct
* answers to the question in the query. If DNSSEC is used, then this section also contains the RRSIG record.
*
* This list is unmodifiable.
*
*/
public final List> answerSection;
/**
* The Authority Section. Note that it is not guaranteed that this section only contains nameserver records. If DNSSEC is used, then this section could also contain a NSEC(3) record.
*
* This list is unmodifiable.
*
*/
public final List> authoritySection;
/**
* The additional section. It eventually contains RRs which relate to the query.
*
* This list is unmodifiable.
*
*/
public final List> additionalSection;
public final int optRrPosition;
/**
* The optional but very common EDNS information. Note that this field is lazily populated.
*
*/
private EDNS edns;
/**
* The receive timestamp. Set only if this message was created via parse.
* This should be used to evaluate TTLs.
*/
public final long receiveTimestamp;
protected DNSMessage(Builder builder) {
this.id = builder.id;
this.opcode = builder.opcode;
this.responseCode = builder.responseCode;
this.receiveTimestamp = builder.receiveTimestamp;
this.qr = builder.query;
this.authoritativeAnswer = builder.authoritativeAnswer;
this.truncated = builder.truncated;
this.recursionDesired = builder.recursionDesired;
this.recursionAvailable = builder.recursionAvailable;
this.authenticData = builder.authenticData;
this.checkingDisabled = builder.checkingDisabled;
if (builder.questions == null) {
this.questions = Collections.emptyList();
} else {
List q = new ArrayList<>(builder.questions.size());
q.addAll(builder.questions);
this.questions = Collections.unmodifiableList(q);
}
if (builder.answers == null) {
this.answerSection = Collections.emptyList();
} else {
List> a = new ArrayList<>(builder.answers.size());
a.addAll(builder.answers);
this.answerSection = Collections.unmodifiableList(a);
}
if (builder.nameserverRecords == null) {
this.authoritySection = Collections.emptyList();
} else {
List> n = new ArrayList<>(builder.nameserverRecords.size());
n.addAll(builder.nameserverRecords);
this.authoritySection = Collections.unmodifiableList(n);
}
if (builder.additionalResourceRecords == null && builder.ednsBuilder == null) {
this.additionalSection = Collections.emptyList();
} else {
int size = 0;
if (builder.additionalResourceRecords != null) {
size += builder.additionalResourceRecords.size();
}
if (builder.ednsBuilder != null) {
size++;
}
List> a = new ArrayList<>(size);
if (builder.additionalResourceRecords != null) {
a.addAll(builder.additionalResourceRecords);
}
if (builder.ednsBuilder != null) {
EDNS edns = builder.ednsBuilder.build();
this.edns = edns;
a.add(edns.asRecord());
}
this.additionalSection = Collections.unmodifiableList(a);
}
optRrPosition = getOptRrPosition(this.additionalSection);
if (optRrPosition != -1) {
// Verify that there are no further OPT records but the one we already found.
for (int i = optRrPosition + 1; i < this.additionalSection.size(); i++) {
if (this.additionalSection.get(i).type == TYPE.OPT) {
throw new IllegalArgumentException("There must be only one OPT pseudo RR in the additional section");
}
}
}
// TODO Add verification of dns message state here
}
/**
* Build a DNS Message based on a binary DNS message.
*
* @param data The DNS message data.
* @throws IOException On read errors.
*/
public DNSMessage(byte data[]) throws IOException {
ByteArrayInputStream bis = new ByteArrayInputStream(data);
DataInputStream dis = new DataInputStream(bis);
id = dis.readUnsignedShort();
int header = dis.readUnsignedShort();
qr = ((header >> 15) & 1) == 1;
opcode = OPCODE.getOpcode((header >> 11) & 0xf);
authoritativeAnswer = ((header >> 10) & 1) == 1;
truncated = ((header >> 9) & 1) == 1;
recursionDesired = ((header >> 8) & 1) == 1;
recursionAvailable = ((header >> 7) & 1) == 1;
authenticData = ((header >> 5) & 1) == 1;
checkingDisabled = ((header >> 4) & 1) == 1;
responseCode = RESPONSE_CODE.getResponseCode(header & 0xf);
receiveTimestamp = System.currentTimeMillis();
int questionCount = dis.readUnsignedShort();
int answerCount = dis.readUnsignedShort();
int nameserverCount = dis.readUnsignedShort();
int additionalResourceRecordCount = dis.readUnsignedShort();
questions = new ArrayList<>(questionCount);
for (int i = 0; i < questionCount; i++) {
questions.add(new Question(dis, data));
}
answerSection = new ArrayList<>(answerCount);
for (int i = 0; i < answerCount; i++) {
answerSection.add(Record.parse(dis, data));
}
authoritySection = new ArrayList<>(nameserverCount);
for (int i = 0; i < nameserverCount; i++) {
authoritySection.add(Record.parse(dis, data));
}
additionalSection = new ArrayList<>(additionalResourceRecordCount);
for (int i = 0; i < additionalResourceRecordCount; i++) {
additionalSection.add(Record.parse(dis, data));
}
optRrPosition = getOptRrPosition(additionalSection);
}
/**
* Constructs an normalized version of the given DNSMessage by setting the id to '0'.
*
* @param message the message of which normalized version should be constructed.
*/
private DNSMessage(DNSMessage message) {
id = 0;
qr = message.qr;
opcode = message.opcode;
authoritativeAnswer = message.authoritativeAnswer;
truncated = message.truncated;
recursionDesired = message.recursionDesired;
recursionAvailable = message.recursionAvailable;
authenticData = message.authenticData;
checkingDisabled = message.checkingDisabled;
responseCode = message.responseCode;
receiveTimestamp = message.receiveTimestamp;
questions = message.questions;
answerSection = message.answerSection;
authoritySection = message.authoritySection;
additionalSection = message.additionalSection;
optRrPosition = message.optRrPosition;
}
private static int getOptRrPosition(List> additionalSection) {
int optRrPosition = -1;
for (int i = 0; i < additionalSection.size(); i++) {
Record record = additionalSection.get(i);
if (record.type == Record.TYPE.OPT) {
optRrPosition = i;
break;
}
}
return optRrPosition;
}
/**
* Generate a binary dns packet out of this message.
*
* @return byte[] the binary representation.
* @throws IOException Should never happen.
*/
public byte[] toArray() throws IOException {
return serialize().clone();
}
public DatagramPacket asDatagram(InetAddress address, int port) {
byte[] bytes = serialize();
return new DatagramPacket(bytes, bytes.length, address, port);
}
public void writeTo(DataOutputStream dataOutputStream) throws IOException {
byte[] bytes = serialize();
dataOutputStream.writeShort(bytes.length);
dataOutputStream.write(bytes);
}
private byte[] byteCache;
private byte[] serialize() {
if (byteCache != null) {
return byteCache;
}
ByteArrayOutputStream baos = new ByteArrayOutputStream(512);
DataOutputStream dos = new DataOutputStream(baos);
int header = calculateHeaderBitmap();
try {
dos.writeShort((short) id);
dos.writeShort((short) header);
if (questions == null) {
dos.writeShort(0);
} else {
dos.writeShort((short) questions.size());
}
if (answerSection == null) {
dos.writeShort(0);
} else {
dos.writeShort((short) answerSection.size());
}
if (authoritySection == null) {
dos.writeShort(0);
} else {
dos.writeShort((short) authoritySection.size());
}
if (additionalSection == null) {
dos.writeShort(0);
} else {
dos.writeShort((short) additionalSection.size());
}
if (questions != null) {
for (Question question : questions) {
dos.write(question.toByteArray());
}
}
if (answerSection != null) {
for (Record answer : answerSection) {
dos.write(answer.toByteArray());
}
}
if (authoritySection != null) {
for (Record nameserverRecord : authoritySection) {
dos.write(nameserverRecord.toByteArray());
}
}
if (additionalSection != null) {
for (Record additionalResourceRecord : additionalSection) {
dos.write(additionalResourceRecord.toByteArray());
}
}
dos.flush();
} catch (IOException e) {
// Should never happen.
throw new AssertionError(e);
}
byteCache = baos.toByteArray();
return byteCache;
}
int calculateHeaderBitmap() {
int header = 0;
if (qr) {
header += 1 << 15;
}
if (opcode != null) {
header += opcode.getValue() << 11;
}
if (authoritativeAnswer) {
header += 1 << 10;
}
if (truncated) {
header += 1 << 9;
}
if (recursionDesired) {
header += 1 << 8;
}
if (recursionAvailable) {
header += 1 << 7;
}
if (authenticData) {
header += 1 << 5;
}
if (checkingDisabled) {
header += 1 << 4;
}
if (responseCode != null) {
header += responseCode.getValue();
}
return header;
}
public Question getQuestion() {
return questions.get(0);
}
/**
* Copy the questions found in the question section.
*
* @return a copy of the question section questions.
* @see #questions
*/
public List copyQuestions() {
List copy = new ArrayList<>(questions.size());
copy.addAll(questions);
return copy;
}
/**
* Copy the records found in the answer section into a new list.
*
* @return a copy of the answer section records.
* @see #answerSection
*/
public List> copyAnswers() {
List> res = new ArrayList<>(answerSection.size());
res.addAll(answerSection);
return res;
}
/**
* Copy the records found in the authority section into a new list.
*
* @return a copy of the authority section records.
* @see #authoritySection
*/
public List> copyAuthority() {
List> res = new ArrayList<>(authoritySection.size());
res.addAll(authoritySection);
return res;
}
public EDNS getEdns() {
if (edns != null) return edns;
Record optRecord = getOptPseudoRecord();
if (optRecord == null) return null;
edns = new EDNS(optRecord);
return edns;
}
@SuppressWarnings("unchecked")
public Record getOptPseudoRecord() {
if (optRrPosition == -1) return null;
return (Record) additionalSection.get(optRrPosition);
}
/**
* Check if the EDNS DO (DNSSEC OK) flag is set.
*
* @return true if the DO flag is set.
*/
public boolean isDnssecOk() {
EDNS edns = getEdns();
if (edns == null)
return false;
return edns.dnssecOk;
}
private String toStringCache;
@Override
public String toString() {
if (toStringCache != null) return toStringCache;
StringBuilder sb = new StringBuilder("DNSMessage")
.append('(').append(id).append(' ')
.append(opcode).append(' ')
.append(responseCode).append(' ');
if (qr) {
sb.append("resp[qr=1]");
} else {
sb.append("query[qr=0]");
}
if (authoritativeAnswer) sb.append(" aa");
if (truncated) sb.append(" tr");
if (recursionDesired) sb.append(" rd");
if (recursionAvailable) sb.append(" ra");
if (authenticData) sb.append(" ad");
if (checkingDisabled) sb.append(" cd");
sb.append(")\n");
if (questions != null) {
for (Question question : questions) {
sb.append("[Q: ").append(question).append("]\n");
}
}
if (answerSection != null) {
for (Record record : answerSection) {
sb.append("[A: ").append(record).append("]\n");
}
}
if (authoritySection != null) {
for (Record record : authoritySection) {
sb.append("[N: ").append(record).append("]\n");
}
}
if (additionalSection != null) {
for (Record record : additionalSection) {
sb.append("[X: ");
EDNS edns = EDNS.fromRecord(record);
if (edns != null) {
sb.append(edns.toString());
} else {
sb.append(record);
}
sb.append("]\n");
}
}
// Strip trailing newline.
if (sb.charAt(sb.length() - 1) == '\n') {
sb.setLength(sb.length() - 1);
}
toStringCache = sb.toString();
return toStringCache;
}
private String terminalOutputCache;
/**
* Format the DNSMessage object in a way suitable for terminal output.
* The format is loosely based on the output provided by {@code dig}.
*
* @return This message as a String suitable for terminal output.
*/
public String asTerminalOutput() {
if (terminalOutputCache != null) return terminalOutputCache;
StringBuilder sb = new StringBuilder(";; ->>HEADER<<-")
.append(" opcode: ").append(opcode)
.append(", status: ").append(responseCode)
.append(", id: ").append(id).append("\n")
.append(";; flags:");
if (!qr) sb.append(" qr");
if (authoritativeAnswer) sb.append(" aa");
if (truncated) sb.append(" tr");
if (recursionDesired) sb.append(" rd");
if (recursionAvailable) sb.append(" ra");
if (authenticData) sb.append(" ad");
if (checkingDisabled) sb.append(" cd");
sb.append("; QUERY: ").append(questions.size())
.append(", ANSWER: ").append(answerSection.size())
.append(", AUTHORITY: ").append(authoritySection.size())
.append(", ADDITIONAL: ").append(additionalSection.size())
.append("\n\n");
for (Record record : additionalSection) {
EDNS edns = EDNS.fromRecord(record);
if (edns != null) {
sb.append(";; OPT PSEUDOSECTION:\n; ").append(edns.asTerminalOutput());
break;
}
}
if (questions.size() != 0) {
sb.append(";; QUESTION SECTION:\n");
for (Question question : questions) {
sb.append(';').append(question.toString()).append('\n');
}
}
if (authoritySection.size() != 0) {
sb.append("\n;; AUTHORITY SECTION:\n");
for (Record record : authoritySection) {
sb.append(record.toString()).append('\n');
}
}
if (answerSection.size() != 0) {
sb.append("\n;; ANSWER SECTION:\n");
for (Record record : answerSection) {
sb.append(record.toString()).append('\n');
}
}
if (additionalSection.size() != 0) {
boolean hasNonOptArr = false;
for (Record record : additionalSection) {
if (record.type != Record.TYPE.OPT) {
if (!hasNonOptArr) {
hasNonOptArr = true;
sb.append("\n;; ADDITIONAL SECTION:\n");
}
sb.append(record.toString()).append('\n');
}
}
}
if (receiveTimestamp > 0) {
sb.append("\n;; WHEN: ").append(new Date(receiveTimestamp).toString());
}
terminalOutputCache = sb.toString();
return terminalOutputCache;
}
public Set getAnswersFor(Question q) {
if (responseCode != RESPONSE_CODE.NO_ERROR) return null;
// It would be great if we could verify that D matches q.type at this
// point. But on the other hand, if it does not, then the cast to D
// below will fail.
Set res = new HashSet<>(answerSection.size());
for (Record record : answerSection) {
if (!record.isAnswer(q)) continue;
Data data = record.getPayload();
@SuppressWarnings("unchecked")
D d = (D) data;
boolean isNew = res.add(d);
if (!isNew) {
LOGGER.log(Level.WARNING, "DNSMessage contains duplicate answers. Record: " + record + "; DNSMessage: " + this);
}
}
return res;
}
public Builder asBuilder() {
return new Builder(this);
}
private DNSMessage normalizedVersionCache;
public DNSMessage asNormalizedVersion() {
if (normalizedVersionCache == null) {
normalizedVersionCache = new DNSMessage(this);
}
return normalizedVersionCache;
}
private transient Integer hashCodeCache;
@Override
public int hashCode() {
if (hashCodeCache == null) {
byte[] bytes = serialize();
hashCodeCache = Arrays.hashCode(bytes);
}
return hashCodeCache;
}
@Override
public boolean equals(Object other) {
if (!(other instanceof DNSMessage)) {
return false;
}
if (other == this) {
return true;
}
DNSMessage otherDnsMessage = (DNSMessage) other;
byte[] otherBytes = otherDnsMessage.serialize();
byte[] myBytes = serialize();
return Arrays.equals(myBytes, otherBytes);
}
public static Builder builder() {
return new DNSMessage.Builder();
}
public static class Builder {
private Builder() {
}
private Builder(DNSMessage message) {
id = message.id;
opcode = message.opcode;
responseCode = message.responseCode;
query = message.qr;
authoritativeAnswer = message.authoritativeAnswer;
truncated = message.truncated;
recursionDesired = message.recursionDesired;
recursionAvailable = message.recursionAvailable;
authenticData = message.authenticData;
checkingDisabled = message.checkingDisabled;
receiveTimestamp = message.receiveTimestamp;
// Copy the unmodifiable lists over into this new builder.
questions = new ArrayList<>(message.questions.size());
questions.addAll(message.questions);
answers = new ArrayList<>(message.answerSection.size());
answers.addAll(message.answerSection);
nameserverRecords = new ArrayList<>(message.authoritySection.size());
nameserverRecords.addAll(message.authoritySection);
additionalResourceRecords = new ArrayList<>(message.additionalSection.size());
additionalResourceRecords.addAll(message.additionalSection);
}
private int id;
private OPCODE opcode = OPCODE.QUERY;
private RESPONSE_CODE responseCode = RESPONSE_CODE.NO_ERROR;
private boolean query;
private boolean authoritativeAnswer;
private boolean truncated;
private boolean recursionDesired;
private boolean recursionAvailable;
private boolean authenticData;
private boolean checkingDisabled;
private long receiveTimestamp = -1;
private List questions;
private List> answers;
private List> nameserverRecords;
private List> additionalResourceRecords;
private EDNS.Builder ednsBuilder;
/**
* Set the current DNS message id.
*
* @param id The new DNS message id.
* @return a reference to this builder.
*/
public Builder setId(int id) {
this.id = id & 0xffff;
return this;
}
public Builder setOpcode(OPCODE opcode) {
this.opcode = opcode;
return this;
}
public Builder setResponseCode(RESPONSE_CODE responseCode) {
this.responseCode = responseCode;
return this;
}
/**
* Set the QR flag.
*
* @param query The new QR flag status.
* @return a reference to this builder.
*/
public Builder setQrFlag(boolean query) {
this.query = query;
return this;
}
/**
* Set the authoritative answer flag.
*
* @param authoritativeAnswer Tge new authoritative answer value.
* @return a reference to this builder.
*/
public Builder setAuthoritativeAnswer(boolean authoritativeAnswer) {
this.authoritativeAnswer = authoritativeAnswer;
return this;
}
/**
* Set the truncation bit on this DNS message.
*
* @param truncated The new truncated bit status.
* @return a reference to this builder.
*/
public Builder setTruncated(boolean truncated) {
this.truncated = truncated;
return this;
}
/**
* Set the recursion desired flag on this message.
*
* @param recursionDesired The new recusrion setting.
* @return a reference to this builder.
*/
public Builder setRecursionDesired(boolean recursionDesired) {
this.recursionDesired = recursionDesired;
return this;
}
/**
* Set the recursion available flog from this DNS message.
*
* @param recursionAvailable The new recursion available status.
* @return a reference to this builder.
*/
public Builder setRecursionAvailable(boolean recursionAvailable) {
this.recursionAvailable = recursionAvailable;
return this;
}
/**
* Set the authentic data flag on this DNS message.
*
* @param authenticData The new authentic data flag value.
* @return a reference to this builder.
*/
public Builder setAuthenticData(boolean authenticData) {
this.authenticData = authenticData;
return this;
}
/**
* Change the check status of this packet.
*
* @param checkingDisabled The new check disabled value.
* @return a reference to this builder.
*/
@Deprecated
public Builder setCheckDisabled(boolean checkingDisabled) {
this.checkingDisabled = checkingDisabled;
return this;
}
/**
* Change the check status of this packet.
*
* @param checkingDisabled The new check disabled value.
* @return a reference to this builder.
*/
public Builder setCheckingDisabled(boolean checkingDisabled) {
this.checkingDisabled = checkingDisabled;
return this;
}
public void copyFlagsFrom(DNSMessage dnsMessage) {
this.query = dnsMessage.qr;
this.authoritativeAnswer = dnsMessage.authenticData;
this.truncated = dnsMessage.truncated;
this.recursionDesired = dnsMessage.recursionDesired;
this.recursionAvailable = dnsMessage.recursionAvailable;
this.authenticData = dnsMessage.authenticData;
this.checkingDisabled = dnsMessage.checkingDisabled;
}
public Builder setReceiveTimestamp(long receiveTimestamp) {
this.receiveTimestamp = receiveTimestamp;
return this;
}
public Builder addQuestion(Question question) {
if (questions == null) {
questions = new ArrayList<>(1);
}
questions.add(question);
return this;
}
/**
* Set the question part of this message.
*
* @param questions The questions.
* @return a reference to this builder.
*/
public Builder setQuestions(List questions) {
this.questions = questions;
return this;
}
/**
* Set the question part of this message.
*
* @param question The question.
* @return a reference to this builder.
*/
public Builder setQuestion(Question question) {
this.questions = new ArrayList<>(1);
this.questions.add(question);
return this;
}
public Builder addAnswer(Record answer) {
if (answers == null) {
answers = new ArrayList<>(1);
}
answers.add(answer);
return this;
}
public Builder addAnswers(Collection> records) {
if (answers == null) {
answers = new ArrayList<>(records.size());
}
answers.addAll(records);
return this;
}
public Builder setAnswers(Collection> records) {
answers = new ArrayList<>(records.size());
answers.addAll(records);
return this;
}
public List> getAnswers() {
if (answers == null) {
return Collections.emptyList();
}
return answers;
}
public Builder addNameserverRecords(Record record) {
if (nameserverRecords == null) {
nameserverRecords = new ArrayList<>(8);
}
nameserverRecords.add(record);
return this;
}
public Builder setNameserverRecords(Collection> records) {
nameserverRecords = new ArrayList<>(records.size());
nameserverRecords.addAll(records);
return this;
}
public Builder setAdditionalResourceRecords(Collection> records) {
additionalResourceRecords = new ArrayList<>(records.size());
additionalResourceRecords.addAll(records);
return this;
}
public Builder addAdditionalResourceRecord(Record record) {
if (additionalResourceRecords == null) {
additionalResourceRecords = new ArrayList<>();
}
additionalResourceRecords.add(record);
return this;
}
public Builder addAdditionalResourceRecords(List> records) {
if (additionalResourceRecords == null) {
additionalResourceRecords = new ArrayList<>(records.size());
}
additionalResourceRecords.addAll(records);
return this;
}
public List> getAdditionalResourceRecords() {
if (additionalResourceRecords == null) {
return Collections.emptyList();
}
return additionalResourceRecords;
}
/**
* Get the @{link EDNS} builder. If no builder has been set so far, then a new one will be created.
*
* The EDNS record can be used to announce the supported size of UDP payload as well as additional flags.
*
*
* Note that some networks and firewalls are known to block big UDP payloads. 1280 should be a reasonable value,
* everything below 512 is treated as 512 and should work on all networks.
*
*
* @return a EDNS builder.
*/
public EDNS.Builder getEdnsBuilder() {
if (ednsBuilder == null) {
ednsBuilder = EDNS.builder();
}
return ednsBuilder;
}
public DNSMessage build() {
return new DNSMessage(this);
}
}
}