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The core module of Pcap4J.
/*_##########################################################################
_##
_## Copyright (C) 2016 Pcap4J.org
_##
_##########################################################################
*/
package org.pcap4j.packet;
import static org.pcap4j.util.ByteArrays.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.pcap4j.packet.namednumber.DnsOpCode;
import org.pcap4j.packet.namednumber.DnsRCode;
import org.pcap4j.util.ByteArrays;
/**
* DNS packet.
*
* @see RFC 1035
* @see DNS
* Header Flags
* @author Kaito Yamada
* @since pcap4j 1.7.1
*/
public final class DnsPacket extends AbstractPacket {
/** */
private static final long serialVersionUID = 2804715680374557063L;
private final DnsHeader header;
/**
* A static factory method. This method validates the arguments by {@link
* ByteArrays#validateBounds(byte[], int, int)}, which may throw exceptions undocumented here.
*
* @param rawData rawData
* @param offset offset
* @param length length
* @return a new DnsPacket object.
* @throws IllegalRawDataException if parsing the raw data fails.
*/
public static DnsPacket newPacket(byte[] rawData, int offset, int length)
throws IllegalRawDataException {
ByteArrays.validateBounds(rawData, offset, length);
return new DnsPacket(rawData, offset, length);
}
private DnsPacket(byte[] rawData, int offset, int length) throws IllegalRawDataException {
this.header = new DnsHeader(rawData, offset, length);
}
private DnsPacket(Builder builder) {
if (builder == null || builder.opCode == null || builder.rCode == null) {
StringBuilder sb = new StringBuilder();
sb.append("builder: ")
.append(builder)
.append(" builder.opCode: ")
.append(builder.opCode)
.append(" builder.rCode: ")
.append(builder.rCode);
throw new NullPointerException(sb.toString());
}
this.header = new DnsHeader(builder);
}
@Override
public DnsHeader getHeader() {
return header;
}
@Override
public Builder getBuilder() {
return new Builder(this);
}
/**
* @author Kaito Yamada
* @since pcap4j 1.7.1
*/
public static final class Builder extends AbstractBuilder {
private short id;
private boolean response;
private DnsOpCode opCode;
private boolean authoritativeAnswer;
private boolean truncated;
private boolean recursionDesired;
private boolean recursionAvailable;
private boolean reserved;
private boolean authenticData;
private boolean checkingDisabled;
private DnsRCode rCode;
private short qdCount;
private short anCount;
private short nsCount;
private short arCount;
private List questions;
private List answers;
private List authorities;
private List additionalInfo;
/** */
public Builder() {}
private Builder(DnsPacket packet) {
this.id = packet.header.id;
this.response = packet.header.response;
this.opCode = packet.header.opCode;
this.authoritativeAnswer = packet.header.authoritativeAnswer;
this.truncated = packet.header.truncated;
this.recursionDesired = packet.header.recursionDesired;
this.recursionAvailable = packet.header.recursionAvailable;
this.reserved = packet.header.reserved;
this.authenticData = packet.header.authenticData;
this.checkingDisabled = packet.header.checkingDisabled;
this.rCode = packet.header.rCode;
this.qdCount = packet.header.qdCount;
this.anCount = packet.header.anCount;
this.nsCount = packet.header.nsCount;
this.arCount = packet.header.arCount;
this.questions = packet.header.questions;
this.answers = packet.header.answers;
this.authorities = packet.header.authorities;
this.additionalInfo = packet.header.additionalInfo;
}
/**
* @param id id
* @return this Builder object for method chaining.
*/
public Builder id(short id) {
this.id = id;
return this;
}
/**
* @param response response
* @return this Builder object for method chaining.
*/
public Builder response(boolean response) {
this.response = response;
return this;
}
/**
* @param opCode opCode
* @return this Builder object for method chaining.
*/
public Builder opCode(DnsOpCode opCode) {
this.opCode = opCode;
return this;
}
/**
* @param authoritativeAnswer authoritativeAnswer
* @return this Builder object for method chaining.
*/
public Builder authoritativeAnswer(boolean authoritativeAnswer) {
this.authoritativeAnswer = authoritativeAnswer;
return this;
}
/**
* @param truncated truncated
* @return this Builder object for method chaining.
*/
public Builder truncated(boolean truncated) {
this.truncated = truncated;
return this;
}
/**
* @param recursionDesired recursionDesired
* @return this Builder object for method chaining.
*/
public Builder recursionDesired(boolean recursionDesired) {
this.recursionDesired = recursionDesired;
return this;
}
/**
* @param recursionAvailable recursionAvailable
* @return this Builder object for method chaining.
*/
public Builder recursionAvailable(boolean recursionAvailable) {
this.recursionAvailable = recursionAvailable;
return this;
}
/**
* @param reserved reserved
* @return this Builder object for method chaining.
*/
public Builder reserved(boolean reserved) {
this.reserved = reserved;
return this;
}
/**
* @param authenticData authenticData
* @return this Builder object for method chaining.
*/
public Builder authenticData(boolean authenticData) {
this.authenticData = authenticData;
return this;
}
/**
* @param checkingDisabled checkingDisabled
* @return this Builder object for method chaining.
*/
public Builder checkingDisabled(boolean checkingDisabled) {
this.checkingDisabled = checkingDisabled;
return this;
}
/**
* @param rCode rCode
* @return this Builder object for method chaining.
*/
public Builder rCode(DnsRCode rCode) {
this.rCode = rCode;
return this;
}
/**
* @param qdCount qdCount
* @return this Builder object for method chaining.
*/
public Builder qdCount(short qdCount) {
this.qdCount = qdCount;
return this;
}
/**
* @param anCount anCount
* @return this Builder object for method chaining.
*/
public Builder anCount(short anCount) {
this.anCount = anCount;
return this;
}
/**
* @param nsCount nsCount
* @return this Builder object for method chaining.
*/
public Builder nsCount(short nsCount) {
this.nsCount = nsCount;
return this;
}
/**
* @param arCount arCount
* @return this Builder object for method chaining.
*/
public Builder arCount(short arCount) {
this.arCount = arCount;
return this;
}
/**
* @param questions questions
* @return this Builder object for method chaining.
*/
public Builder questions(List questions) {
this.questions = questions;
return this;
}
/**
* @param answers answers
* @return this Builder object for method chaining.
*/
public Builder answers(List answers) {
this.answers = answers;
return this;
}
/**
* @param authorities authorities
* @return this Builder object for method chaining.
*/
public Builder authorities(List authorities) {
this.authorities = authorities;
return this;
}
/**
* @param additionalInfo additionalInfo
* @return this Builder object for method chaining.
*/
public Builder additionalInfo(List additionalInfo) {
this.additionalInfo = additionalInfo;
return this;
}
@Override
public DnsPacket build() {
return new DnsPacket(this);
}
}
/**
* DNS header
*
*
* +---------------------+
* | Header |
* +---------------------+
* | Question | the question for the name server
* +---------------------+
* | Answer | RRs answering the question
* +---------------------+
* | Authority | RRs pointing toward an authority
* +---------------------+
* | Additional | RRs holding additional information
* +---------------------+
*
* Header:
* 1 1 1 1 1 1
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | ID |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* |QR| Opcode |AA|TC|RD|RA| Z|AD|CD| RCODE |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | QDCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | ANCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | NSCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
* | ARCOUNT |
* +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
*
*
* @see RFC 1035
* @see RFC 2535
* @author Kaito Yamada
* @version pcap4j 1.7.1
*/
public static final class DnsHeader extends AbstractHeader {
/** */
private static final long serialVersionUID = -2779530760536525672L;
private static final int ID_OFFSET = 0;
private static final int ID_SIZE = SHORT_SIZE_IN_BYTES;
private static final int FLAGS_OFFSET = ID_OFFSET + ID_SIZE;
private static final int FLAGS_SIZE = SHORT_SIZE_IN_BYTES;
private static final int QDCOUNT_OFFSET = FLAGS_OFFSET + FLAGS_SIZE;
private static final int QDCOUNT_SIZE = SHORT_SIZE_IN_BYTES;
private static final int ANCOUNT_OFFSET = QDCOUNT_OFFSET + QDCOUNT_SIZE;
private static final int ANCOUNT_SIZE = SHORT_SIZE_IN_BYTES;
private static final int NSCOUNT_OFFSET = ANCOUNT_OFFSET + ANCOUNT_SIZE;
private static final int NSCOUNT_SIZE = SHORT_SIZE_IN_BYTES;
private static final int ARCOUNT_OFFSET = NSCOUNT_OFFSET + NSCOUNT_SIZE;
private static final int ARCOUNT_SIZE = SHORT_SIZE_IN_BYTES;
private static final int DNS_MIN_HEADER_SIZE = ARCOUNT_OFFSET + ARCOUNT_SIZE;
private final short id;
private final boolean response;
private final DnsOpCode opCode;
private final boolean authoritativeAnswer;
private final boolean truncated;
private final boolean recursionDesired;
private final boolean recursionAvailable;
private final boolean reserved;
private final boolean authenticData;
private final boolean checkingDisabled;
private final DnsRCode rCode;
private final short qdCount;
private final short anCount;
private final short nsCount;
private final short arCount;
private final List questions;
private final List answers;
private final List authorities;
private final List additionalInfo;
private DnsHeader(byte[] rawData, int offset, int length) throws IllegalRawDataException {
if (length < DNS_MIN_HEADER_SIZE) {
StringBuilder sb = new StringBuilder(200);
sb.append("The data is too short to build a DnsHeader (")
.append(DNS_MIN_HEADER_SIZE)
.append(" bytes). data: ")
.append(ByteArrays.toHexString(rawData, " "))
.append(", offset: ")
.append(offset)
.append(", length: ")
.append(length);
throw new IllegalRawDataException(sb.toString());
}
this.id = ByteArrays.getShort(rawData, ID_OFFSET + offset);
short flags = ByteArrays.getShort(rawData, FLAGS_OFFSET + offset);
this.response = (flags & 0x8000) != 0;
this.opCode = DnsOpCode.getInstance((byte) ((flags >> 11) & 0x0F));
this.authoritativeAnswer = (flags & 0x0400) != 0;
this.truncated = (flags & 0x0200) != 0;
this.recursionDesired = (flags & 0x0100) != 0;
this.recursionAvailable = (flags & 0x0080) != 0;
this.reserved = (flags & 0x0040) != 0;
this.authenticData = (flags & 0x0020) != 0;
this.checkingDisabled = (flags & 0x0010) != 0;
this.rCode = DnsRCode.getInstance((byte) (flags & 0x0F));
this.qdCount = ByteArrays.getShort(rawData, QDCOUNT_OFFSET + offset);
this.anCount = ByteArrays.getShort(rawData, ANCOUNT_OFFSET + offset);
this.nsCount = ByteArrays.getShort(rawData, NSCOUNT_OFFSET + offset);
this.arCount = ByteArrays.getShort(rawData, ARCOUNT_OFFSET + offset);
int qdCnt = getQdCountAsInt();
int anCnt = getAnCountAsInt();
int nsCnt = getNsCountAsInt();
int arCnt = getArCountAsInt();
this.questions = new ArrayList(qdCnt);
this.answers = new ArrayList(anCnt);
this.authorities = new ArrayList(nsCnt);
this.additionalInfo = new ArrayList(arCnt);
int cursor = DNS_MIN_HEADER_SIZE;
for (int i = 0; i < qdCnt; i++) {
int remainingLen = length - cursor;
if (remainingLen == 0) {
StringBuilder sb = new StringBuilder(200);
sb.append("The data is too short to build a question in DnsHeader. data: ")
.append(ByteArrays.toHexString(rawData, " "))
.append(", offset: ")
.append(offset)
.append(", length: ")
.append(length)
.append(", cursor: ")
.append(cursor);
throw new IllegalRawDataException(sb.toString());
}
DnsQuestion question = DnsQuestion.newInstance(rawData, offset + cursor, remainingLen);
questions.add(question);
cursor += question.length();
}
for (int i = 0; i < anCnt; i++) {
int remainingLen = length - cursor;
if (remainingLen == 0) {
StringBuilder sb = new StringBuilder(200);
sb.append("The data is too short to build an answer in DnsHeader. data: ")
.append(ByteArrays.toHexString(rawData, " "))
.append(", offset: ")
.append(offset)
.append(", length: ")
.append(length)
.append(", cursor: ")
.append(cursor);
throw new IllegalRawDataException(sb.toString());
}
DnsResourceRecord answer =
DnsResourceRecord.newInstance(rawData, offset + cursor, remainingLen);
answers.add(answer);
cursor += answer.length();
}
for (int i = 0; i < nsCnt; i++) {
int remainingLen = length - cursor;
if (remainingLen == 0) {
StringBuilder sb = new StringBuilder(200);
sb.append("The data is too short to build an authority in DnsHeader. data: ")
.append(ByteArrays.toHexString(rawData, " "))
.append(", offset: ")
.append(offset)
.append(", length: ")
.append(length)
.append(", cursor: ")
.append(cursor);
throw new IllegalRawDataException(sb.toString());
}
DnsResourceRecord authority =
DnsResourceRecord.newInstance(rawData, offset + cursor, remainingLen);
authorities.add(authority);
cursor += authority.length();
}
for (int i = 0; i < arCnt; i++) {
int remainingLen = length - cursor;
if (remainingLen == 0) {
StringBuilder sb = new StringBuilder(200);
sb.append("The data is too short to build additional info in DnsHeader. data: ")
.append(ByteArrays.toHexString(rawData, " "))
.append(", offset: ")
.append(offset)
.append(", length: ")
.append(length)
.append(", cursor: ")
.append(cursor);
throw new IllegalRawDataException(sb.toString());
}
DnsResourceRecord info =
DnsResourceRecord.newInstance(rawData, offset + cursor, remainingLen);
additionalInfo.add(info);
cursor += info.length();
}
}
private DnsHeader(Builder builder) {
this.id = builder.id;
this.response = builder.response;
this.opCode = builder.opCode;
this.authoritativeAnswer = builder.authoritativeAnswer;
this.truncated = builder.truncated;
this.recursionDesired = builder.recursionDesired;
this.recursionAvailable = builder.recursionAvailable;
this.reserved = builder.reserved;
this.authenticData = builder.authenticData;
this.checkingDisabled = builder.checkingDisabled;
this.rCode = builder.rCode;
this.qdCount = builder.qdCount;
this.anCount = builder.anCount;
this.nsCount = builder.nsCount;
this.arCount = builder.arCount;
if (builder.questions != null) {
if (builder.questions.size() > 65535) {
throw new IllegalArgumentException(
"The number of questions must be less than 65536. builder.questions.size(): "
+ builder.questions.size());
}
this.questions = new ArrayList(builder.questions);
} else {
this.questions = Collections.emptyList();
}
if (builder.answers != null) {
if (builder.answers.size() > 65535) {
throw new IllegalArgumentException(
"The number of answers must be less than 65536. builder.answers.size(): "
+ builder.answers.size());
}
this.answers = new ArrayList(builder.answers);
} else {
this.answers = Collections.emptyList();
}
if (builder.authorities != null) {
if (builder.authorities.size() > 65535) {
throw new IllegalArgumentException(
"The number of authorities must be less than 65536. builder.authorities.size(): "
+ builder.authorities.size());
}
this.authorities = new ArrayList(builder.authorities);
} else {
this.authorities = Collections.emptyList();
}
if (builder.additionalInfo != null) {
if (builder.additionalInfo.size() > 65535) {
throw new IllegalArgumentException(
"The number of additionalInfo elements must be less than 65536."
+ " builder.additionalInfo.size(): "
+ builder.additionalInfo.size());
}
this.additionalInfo = new ArrayList(builder.additionalInfo);
} else {
this.additionalInfo = Collections.emptyList();
}
}
/** @return id */
public short getId() {
return id;
}
/** @return true if the QR bit is set to 1; false otherwise. */
public boolean isResponse() {
return response;
}
/** @return opCode */
public DnsOpCode getOpCode() {
return opCode;
}
/** @return true if the AA bit is set to 1; false otherwise. */
public boolean isAuthoritativeAnswer() {
return authoritativeAnswer;
}
/** @return true if the TC bit is set to 1; false otherwise. */
public boolean isTruncated() {
return truncated;
}
/** @return true if the RD bit is set to 1; false otherwise. */
public boolean isRecursionDesired() {
return recursionDesired;
}
/** @return true if the RA bit is set to 1; false otherwise. */
public boolean isRecursionAvailable() {
return recursionAvailable;
}
/** @return true if the Z bit is set to 1; false otherwise. */
public boolean getReservedBit() {
return reserved;
}
/** @return true if the AD bit is set to 1; false otherwise. */
public boolean isAuthenticData() {
return authenticData;
}
/** @return true if the CD bit is set to 1; false otherwise. */
public boolean isCheckingDisabled() {
return checkingDisabled;
}
/** @return rCode */
public DnsRCode getrCode() {
return rCode;
}
/** @return qdCount */
public short getQdCount() {
return qdCount;
}
/** @return qdCount */
public int getQdCountAsInt() {
return qdCount & 0xFFFF;
}
/** @return anCount */
public short getAnCount() {
return anCount;
}
/** @return anCount */
public int getAnCountAsInt() {
return anCount & 0xFFFF;
}
/** @return nsCount */
public short getNsCount() {
return nsCount;
}
/** @return nsCount */
public int getNsCountAsInt() {
return nsCount & 0xFFFF;
}
/** @return arCount */
public short getArCount() {
return arCount;
}
/** @return arCount */
public int getArCountAsInt() {
return arCount & 0xFFFF;
}
/** @return questions */
public List getQuestions() {
return new ArrayList(questions);
}
/** @return answers */
public List getAnswers() {
return new ArrayList(answers);
}
/** @return authorities */
public List getAuthorities() {
return new ArrayList(authorities);
}
/** @return additionalInfo */
public List getAdditionalInfo() {
return new ArrayList(additionalInfo);
}
@Override
protected List getRawFields() {
List rawFields = new ArrayList();
rawFields.add(ByteArrays.toByteArray(id));
byte[] flags = new byte[2];
flags[0] = (byte) (opCode.value() << 3);
if (response) {
flags[0] |= 0x80;
}
if (authoritativeAnswer) {
flags[0] |= 0x04;
}
if (truncated) {
flags[0] |= 0x02;
}
if (recursionDesired) {
flags[0] |= 0x01;
}
flags[1] = rCode.value();
if (recursionAvailable) {
flags[1] |= 0x80;
}
if (reserved) {
flags[1] |= 0x40;
}
if (authenticData) {
flags[1] |= 0x20;
}
if (checkingDisabled) {
flags[1] |= 0x10;
}
rawFields.add(flags);
rawFields.add(ByteArrays.toByteArray(qdCount));
rawFields.add(ByteArrays.toByteArray(anCount));
rawFields.add(ByteArrays.toByteArray(nsCount));
rawFields.add(ByteArrays.toByteArray(arCount));
for (DnsQuestion question : questions) {
rawFields.add(question.getRawData());
}
for (DnsResourceRecord answer : answers) {
rawFields.add(answer.getRawData());
}
for (DnsResourceRecord authority : authorities) {
rawFields.add(authority.getRawData());
}
for (DnsResourceRecord info : additionalInfo) {
rawFields.add(info.getRawData());
}
return rawFields;
}
@Override
public int length() {
int len = DNS_MIN_HEADER_SIZE;
for (DnsQuestion question : questions) {
len += question.length();
}
for (DnsResourceRecord answer : answers) {
len += answer.length();
}
for (DnsResourceRecord authority : authorities) {
len += authority.length();
}
for (DnsResourceRecord info : additionalInfo) {
len += info.length();
}
return len;
}
@Override
protected String buildString() {
StringBuilder sb = new StringBuilder();
String ls = System.getProperty("line.separator");
sb.append("[DNS Header (").append(length()).append(" bytes)]").append(ls);
sb.append(" ID: ").append("0x" + ByteArrays.toHexString(id, "")).append(ls);
sb.append(" QR: ").append(response ? "response" : "query").append(ls);
sb.append(" OPCODE: ").append(opCode).append(ls);
sb.append(" Authoritative Answer: ").append(authoritativeAnswer).append(ls);
sb.append(" Truncated: ").append(truncated).append(ls);
sb.append(" Recursion Desired: ").append(recursionDesired).append(ls);
sb.append(" Recursion Available: ").append(recursionAvailable).append(ls);
sb.append(" Reserved Bit: ").append(reserved ? 1 : 0).append(ls);
sb.append(" Authentic Data: ").append(authenticData).append(ls);
sb.append(" Checking Disabled: ").append(checkingDisabled).append(ls);
sb.append(" RCODE: ").append(rCode).append(ls);
sb.append(" QDCOUNT: ").append(qdCount).append(ls);
sb.append(" ANCOUNT: ").append(anCount).append(ls);
sb.append(" NSCOUNT: ").append(nsCount).append(ls);
sb.append(" ARCOUNT: ").append(arCount).append(ls);
byte[] headerRawData = getRawData();
for (DnsQuestion question : questions) {
sb.append(" Question:").append(ls).append(question.toString(" ", headerRawData));
}
for (DnsResourceRecord answer : answers) {
sb.append(" Answer:").append(ls).append(answer.toString(" ", headerRawData));
}
for (DnsResourceRecord authority : authorities) {
sb.append(" Authority:").append(ls).append(authority.toString(" ", headerRawData));
}
for (DnsResourceRecord info : additionalInfo) {
sb.append(" Additional:").append(ls).append(info.toString(" ", headerRawData));
}
return sb.toString();
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!super.equals(obj)) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
DnsHeader other = (DnsHeader) obj;
if (!additionalInfo.equals(other.additionalInfo)) {
return false;
}
if (anCount != other.anCount) {
return false;
}
if (!answers.equals(other.answers)) {
return false;
}
if (arCount != other.arCount) {
return false;
}
if (authenticData != other.authenticData) {
return false;
}
if (authoritativeAnswer != other.authoritativeAnswer) {
return false;
}
if (!authorities.equals(other.authorities)) {
return false;
}
if (checkingDisabled != other.checkingDisabled) {
return false;
}
if (id != other.id) {
return false;
}
if (nsCount != other.nsCount) {
return false;
}
if (!opCode.equals(other.opCode)) {
return false;
}
if (qdCount != other.qdCount) {
return false;
}
if (!questions.equals(other.questions)) {
return false;
}
if (!rCode.equals(other.rCode)) {
return false;
}
if (recursionAvailable != other.recursionAvailable) {
return false;
}
if (recursionDesired != other.recursionDesired) {
return false;
}
if (reserved != other.reserved) {
return false;
}
if (response != other.response) {
return false;
}
if (truncated != other.truncated) {
return false;
}
return true;
}
@Override
protected int calcHashCode() {
final int prime = 31;
int result = 17;
result = prime * result + additionalInfo.hashCode();
result = prime * result + anCount;
result = prime * result + answers.hashCode();
result = prime * result + arCount;
result = prime * result + (authenticData ? 1231 : 1237);
result = prime * result + (authoritativeAnswer ? 1231 : 1237);
result = prime * result + authorities.hashCode();
result = prime * result + (checkingDisabled ? 1231 : 1237);
result = prime * result + id;
result = prime * result + nsCount;
result = prime * result + opCode.hashCode();
result = prime * result + qdCount;
result = prime * result + questions.hashCode();
result = prime * result + rCode.hashCode();
result = prime * result + (recursionAvailable ? 1231 : 1237);
result = prime * result + (recursionDesired ? 1231 : 1237);
result = prime * result + (reserved ? 1231 : 1237);
result = prime * result + (response ? 1231 : 1237);
result = prime * result + (truncated ? 1231 : 1237);
return result;
}
}
}
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