Revamp DNS codec

Motivation:

There are various known issues in netty-codec-dns:

- Message types are not interfaces, which can make it difficult for a
  user to implement his/her own message implementation.
- Some class names and field names do not match with the terms in the
  RFC.
- The support for decoding a DNS record was limited. A user had to
  encode and decode by him/herself.
- The separation of DnsHeader from DnsMessage was unnecessary, although
  it is fine conceptually.
- Buffer leak caused by DnsMessage was difficult to analyze, because the
  leak detector tracks down the underlying ByteBuf rather than the
  DnsMessage itself.
- DnsMessage assumes DNS-over-UDP.
- To send an EDNS message, a user have to create a new DNS record class
  instance unnecessarily.

Modifications:

- Make all message types interfaces and add default implementations
- Rename some classes, properties, and constants to match the RFCs
  - DnsResource -> DnsRecord
  - DnsType -> DnsRecordType
  - and many more
- Remove DnsClass and use an integer to support EDNS better
- Add DnsRecordEncoder/DnsRecordDecoder and their default
  implementations
  - DnsRecord does not require RDATA to be ByteBuf anymore.
  - Add DnsRawRecord as the catch-all record type
- Merge DnsHeader into DnsMessage
- Make ResourceLeakDetector track AbstractDnsMessage
- Remove DnsMessage.sender/recipient properties
  - Wrap DnsMessage with AddressedEnvelope
  - Add DatagramDnsQuest and DatagramDnsResponse for ease of use
  - Rename DnsQueryEncoder to DatagramDnsQueryEncoder
  - Rename DnsResponseDecoder to DatagramDnsResponseDecoder
- Miscellaneous changes
  - Add StringUtil.TAB

Result:

- Cleaner APi
- Can support DNS-over-TCP more easily in the future
- Reduced memory footprint in the default DnsQuery/Response
  implementations
- Better leak tracking for DnsMessages
- Possibility to introduce new DnsRecord types in the future and provide
  full record encoder/decoder implementation.
- No unnecessary instantiation for an EDNS pseudo resource record

codec-dns/src/main/java/io/netty/handler/codec/dns/AbstractDnsMessage.java

@@ -0,0 +1,465 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.util.AbstractReferenceCounted;
+import io.netty.util.ReferenceCountUtil;
+import io.netty.util.ReferenceCounted;
+import io.netty.util.ResourceLeak;
+import io.netty.util.ResourceLeakDetector;
+import io.netty.util.internal.StringUtil;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+
+/**
+ * A skeletal implementation of {@link DnsMessage}.
+ */
+public abstract class AbstractDnsMessage extends AbstractReferenceCounted implements DnsMessage {
+
+    private static final ResourceLeakDetector<DnsMessage> leakDetector =
+            new ResourceLeakDetector<DnsMessage>(DnsMessage.class);
+
+    private static final int SECTION_QUESTION = DnsSection.QUESTION.ordinal();
+    private static final int SECTION_COUNT = 4;
+
+    private final ResourceLeak leak = leakDetector.open(this);
+    private short id;
+    private DnsOpCode opCode;
+    private boolean recursionDesired;
+    private byte z;
+
+    // To reduce the memory footprint of a message,
+    // each of the following fields is a single record or a list of records.
+    private Object questions;
+    private Object answers;
+    private Object authorities;
+    private Object additionals;
+
+    /**
+     * Creates a new instance with the specified {@code id} and {@link DnsOpCode#QUERY} opCode.
+     */
+    protected AbstractDnsMessage(int id) {
+        this(id, DnsOpCode.QUERY);
+    }
+
+    /**
+     * Creates a new instance with the specified {@code id} and {@code opCode}.
+     */
+    protected AbstractDnsMessage(int id, DnsOpCode opCode) {
+        setId(id);
+        setOpCode(opCode);
+    }
+
+    @Override
+    public int id() {
+        return id & 0xFFFF;
+    }
+
+    @Override
+    public DnsMessage setId(int id) {
+        this.id = (short) id;
+        return this;
+    }
+
+    @Override
+    public DnsOpCode opCode() {
+        return opCode;
+    }
+
+    @Override
+    public DnsMessage setOpCode(DnsOpCode opCode) {
+        this.opCode = checkNotNull(opCode, "opCode");
+        return this;
+    }
+
+    @Override
+    public boolean isRecursionDesired() {
+        return recursionDesired;
+    }
+
+    @Override
+    public DnsMessage setRecursionDesired(boolean recursionDesired) {
+        this.recursionDesired = recursionDesired;
+        return this;
+    }
+
+    @Override
+    public int z() {
+        return z;
+    }
+
+    @Override
+    public DnsMessage setZ(int z) {
+        this.z = (byte) (z & 7);
+        return this;
+    }
+
+    @Override
+    public int count(DnsSection section) {
+        return count(sectionOrdinal(section));
+    }
+
+    private int count(int section) {
+        final Object records = sectionAt(section);
+        if (records == null) {
+            return 0;
+        }
+        if (records instanceof DnsRecord) {
+            return 1;
+        }
+
+        @SuppressWarnings("unchecked")
+        final List<DnsRecord> recordList = (List<DnsRecord>) records;
+        return recordList.size();
+    }
+
+    @Override
+    public int count() {
+        int count = 0;
+        for (int i = 0; i < SECTION_COUNT; i ++) {
+            count += count(i);
+        }
+        return count;
+    }
+
+    @Override
+    public <T extends DnsRecord> T recordAt(DnsSection section) {
+        return recordAt(sectionOrdinal(section));
+    }
+
+    private <T extends DnsRecord> T recordAt(int section) {
+        final Object records = sectionAt(section);
+        if (records == null) {
+            return null;
+        }
+
+        if (records instanceof DnsRecord) {
+            return castRecord(records);
+        }
+
+        @SuppressWarnings("unchecked")
+        final List<DnsRecord> recordList = (List<DnsRecord>) records;
+        if (recordList.isEmpty()) {
+            return null;
+        }
+
+        return castRecord(recordList.get(0));
+    }
+
+    @Override
+    public <T extends DnsRecord> T recordAt(DnsSection section, int index) {
+        return recordAt(sectionOrdinal(section), index);
+    }
+
+    private <T extends DnsRecord> T recordAt(int section, int index) {
+        final Object records = sectionAt(section);
+        if (records == null) {
+            throw new IndexOutOfBoundsException("index: " + index + " (expected: none)");
+        }
+
+        if (records instanceof DnsRecord) {
+            if (index == 0) {
+                return castRecord(records);
+            } else {
+                throw new IndexOutOfBoundsException("index: " + index + "' (expected: 0)");
+            }
+        }
+
+        @SuppressWarnings("unchecked")
+        final List<DnsRecord> recordList = (List<DnsRecord>) records;
+        return castRecord(recordList.get(index));
+    }
+
+    @Override
+    public DnsMessage setRecord(DnsSection section, DnsRecord record) {
+        setRecord(sectionOrdinal(section), record);
+        return this;
+    }
+
+    private void setRecord(int section, DnsRecord record) {
+        clear(section);
+        setSection(section, checkQuestion(section, record));
+    }
+
+    @Override
+    public <T extends DnsRecord> T setRecord(DnsSection section, int index, DnsRecord record) {
+        return setRecord(sectionOrdinal(section), index, record);
+    }
+
+    private <T extends DnsRecord> T setRecord(int section, int index, DnsRecord record) {
+        checkQuestion(section, record);
+
+        final Object records = sectionAt(section);
+        if (records == null) {
+            throw new IndexOutOfBoundsException("index: " + index + " (expected: none)");
+        }
+
+        if (records instanceof DnsRecord) {
+            if (index == 0) {
+                setSection(section, record);
+                return castRecord(records);
+            } else {
+                throw new IndexOutOfBoundsException("index: " + index + " (expected: 0)");
+            }
+        }
+
+        @SuppressWarnings("unchecked")
+        final List<DnsRecord> recordList = (List<DnsRecord>) records;
+        return castRecord(recordList.set(index, record));
+    }
+
+    @Override
+    public DnsMessage addRecord(DnsSection section, DnsRecord record) {
+        addRecord(sectionOrdinal(section), record);
+        return this;
+    }
+
+    private void addRecord(int section, DnsRecord record) {
+        checkQuestion(section, record);
+
+        final Object records = sectionAt(section);
+        if (records == null) {
+            setSection(section, record);
+            return;
+        }
+
+        if (records instanceof DnsRecord) {
+            final List<DnsRecord> recordList = newRecordList();
+            recordList.add(castRecord(records));
+            recordList.add(record);
+            setSection(section, recordList);
+            return;
+        }
+
+        @SuppressWarnings("unchecked")
+        final List<DnsRecord> recordList = (List<DnsRecord>) records;
+        recordList.add(record);
+    }
+
+    @Override
+    public DnsMessage addRecord(DnsSection section, int index, DnsRecord record) {
+        addRecord(sectionOrdinal(section), index, record);
+        return this;
+    }
+
+    private void addRecord(int section, int index, DnsRecord record) {
+        checkQuestion(section, record);
+
+        final Object records = sectionAt(section);
+        if (records == null) {
+            if (index != 0) {
+                throw new IndexOutOfBoundsException("index: " + index + " (expected: 0)");
+            }
+
+            setSection(section, record);
+            return;
+        }
+
+        if (records instanceof DnsRecord) {
+            final List<DnsRecord> recordList;
+            if (index == 0) {
+                recordList = newRecordList();
+                recordList.add(record);
+                recordList.add(castRecord(records));
+            } else if (index == 1) {
+                recordList = newRecordList();
+                recordList.add(castRecord(records));
+                recordList.add(record);
+            } else {
+                throw new IndexOutOfBoundsException("index: " + index + " (expected: 0 or 1)");
+            }
+            setSection(section, recordList);
+            return;
+        }
+
+        @SuppressWarnings("unchecked")
+        final List<DnsRecord> recordList = (List<DnsRecord>) records;
+        recordList.add(index, record);
+    }
+
+    @Override
+    public <T extends DnsRecord> T removeRecord(DnsSection section, int index) {
+        return removeRecord(sectionOrdinal(section), index);
+    }
+
+    private <T extends DnsRecord> T removeRecord(int section, int index) {
+        final Object records = sectionAt(section);
+        if (records == null) {
+            throw new IndexOutOfBoundsException("index: " + index + " (expected: none)");
+        }
+
+        if (records instanceof DnsRecord) {
+            if (index != 0) {
+                throw new IndexOutOfBoundsException("index: " + index + " (expected: 0)");
+            }
+
+            T record = castRecord(records);
+            setSection(section, null);
+            return record;
+        }
+
+        @SuppressWarnings("unchecked")
+        final List<DnsRecord> recordList = (List<DnsRecord>) records;
+        return castRecord(recordList.remove(index));
+    }
+
+    @Override
+    public DnsMessage clear(DnsSection section) {
+        clear(sectionOrdinal(section));
+        return this;
+    }
+
+    @Override
+    public DnsMessage clear() {
+        for (int i = 0; i < SECTION_COUNT; i ++) {
+            clear(i);
+        }
+        return this;
+    }
+
+    private void clear(int section) {
+        final Object recordOrList = sectionAt(section);
+        setSection(section, null);
+        if (recordOrList instanceof ReferenceCounted) {
+            ((ReferenceCounted) recordOrList).release();
+        } else if (recordOrList instanceof List) {
+            @SuppressWarnings("unchecked")
+            List<DnsRecord> list = (List<DnsRecord>) recordOrList;
+            if (!list.isEmpty()) {
+                for (Object r : list) {
+                    ReferenceCountUtil.release(r);
+                }
+            }
+        }
+    }
+
+    @Override
+    public DnsMessage touch() {
+        return (DnsMessage) super.touch();
+    }
+
+    @Override
+    public DnsMessage touch(Object hint) {
+        if (leak != null) {
+            leak.record(hint);
+        }
+        return this;
+    }
+
+    @Override
+    public DnsMessage retain() {
+        return (DnsMessage) super.retain();
+    }
+
+    @Override
+    public DnsMessage retain(int increment) {
+        return (DnsMessage) super.retain(increment);
+    }
+
+    @Override
+    protected void deallocate() {
+        clear();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (!(obj instanceof DnsMessage)) {
+            return false;
+        }
+
+        final DnsMessage that = (DnsMessage) obj;
+        if (id() != that.id()) {
+            return false;
+        }
+
+        if (this instanceof DnsQuery) {
+            if (!(that instanceof DnsQuery)) {
+                return false;
+            }
+        } else if (that instanceof DnsQuery) {
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public int hashCode() {
+        return id() * 31 + (this instanceof DnsQuery? 0 : 1);
+    }
+
+    private Object sectionAt(int section) {
+        switch (section) {
+        case 0:
+            return questions;
+        case 1:
+            return answers;
+        case 2:
+            return authorities;
+        case 3:
+            return additionals;
+        }
+
+        throw new Error(); // Should never reach here.
+    }
+
+    private void setSection(int section, Object value) {
+        switch (section) {
+        case 0:
+            questions = value;
+            return;
+        case 1:
+            answers = value;
+            return;
+        case 2:
+            authorities = value;
+            return;
+        case 3:
+            additionals = value;
+            return;
+        }
+
+        throw new Error(); // Should never reach here.
+    }
+
+    private static int sectionOrdinal(DnsSection section) {
+        return checkNotNull(section, "section").ordinal();
+    }
+
+    private static DnsRecord checkQuestion(int section, DnsRecord record) {
+        if (section == SECTION_QUESTION && !(checkNotNull(record, "record") instanceof DnsQuestion)) {
+            throw new IllegalArgumentException(
+                    "record: " + record + " (expected: " + StringUtil.simpleClassName(DnsQuestion.class) + ')');
+        }
+        return record;
+    }
+
+    @SuppressWarnings("unchecked")
+    private static <T extends DnsRecord> T castRecord(Object record) {
+        return (T) record;
+    }
+
+    private static ArrayList<DnsRecord> newRecordList() {
+        return new ArrayList<DnsRecord>(2);
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/AbstractDnsRecord.java

@@ -0,0 +1,139 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.util.internal.StringUtil;
+
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+
+/**
+ * A skeletal implementation of {@link DnsRecord}.
+ */
+public abstract class AbstractDnsRecord implements DnsRecord {
+
+    private final String name;
+    private final DnsRecordType type;
+    private final short dnsClass;
+    private final long timeToLive;
+    private int hashCode;
+
+    /**
+     * Creates a new {@link #CLASS_IN IN-class} record.
+     *
+     * @param name the domain name
+     * @param type the type of the record
+     * @param timeToLive the TTL value of the record
+     */
+    protected AbstractDnsRecord(String name, DnsRecordType type, long timeToLive) {
+        this(name, type, CLASS_IN, timeToLive);
+    }
+
+    /**
+     * Creates a new record.
+     *
+     * @param name the domain name
+     * @param type the type of the record
+     * @param dnsClass the class of the record, usually one of the following:
+     *                 <ul>
+     *                     <li>{@link #CLASS_IN}</li>
+     *                     <li>{@link #CLASS_CSNET}</li>
+     *                     <li>{@link #CLASS_CHAOS}</li>
+     *                     <li>{@link #CLASS_HESIOD}</li>
+     *                     <li>{@link #CLASS_NONE}</li>
+     *                     <li>{@link #CLASS_ANY}</li>
+     *                 </ul>
+     * @param timeToLive the TTL value of the record
+     */
+    protected AbstractDnsRecord(String name, DnsRecordType type, int dnsClass, long timeToLive) {
+        if (timeToLive < 0) {
+            throw new IllegalArgumentException("timeToLive: " + timeToLive + " (expected: >= 0)");
+        }
+        this.name = checkNotNull(name, "name");
+        this.type = checkNotNull(type, "type");
+        this.dnsClass = (short) dnsClass;
+        this.timeToLive = timeToLive;
+    }
+
+    @Override
+    public String name() {
+        return name;
+    }
+
+    @Override
+    public DnsRecordType type() {
+        return type;
+    }
+
+    @Override
+    public int dnsClass() {
+        return dnsClass & 0xFFFF;
+    }
+
+    @Override
+    public long timeToLive() {
+        return timeToLive;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (!(obj instanceof DnsRecord)) {
+            return false;
+        }
+
+        final DnsRecord that = (DnsRecord) obj;
+        final int hashCode = this.hashCode;
+        if (hashCode != 0 && hashCode != that.hashCode()) {
+            return false;
+        }
+
+        return type().intValue() == that.type().intValue() &&
+               dnsClass() == that.dnsClass() &&
+               name().equals(that.name());
+    }
+
+    @Override
+    public int hashCode() {
+        final int hashCode = this.hashCode;
+        if (hashCode != 0) {
+            return hashCode;
+        }
+
+        return this.hashCode = name.hashCode() * 31 + type().intValue() * 31 + dnsClass();
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder buf = new StringBuilder(64);
+
+        buf.append(StringUtil.simpleClassName(this))
+           .append('(')
+           .append(name())
+           .append(' ')
+           .append(timeToLive())
+           .append(' ');
+
+        DnsMessageUtil.appendRecordClass(buf, dnsClass())
+                      .append(' ')
+                      .append(type().name())
+                      .append(')');
+
+        return buf.toString();
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DatagramDnsQuery.java

@@ -0,0 +1,190 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.channel.AddressedEnvelope;
+
+import java.net.InetSocketAddress;
+import java.net.SocketAddress;
+
+/**
+ * A {@link DnsQuery} implementation for UDP/IP.
+ */
+public class DatagramDnsQuery extends DefaultDnsQuery
+        implements AddressedEnvelope<DatagramDnsQuery, InetSocketAddress> {
+
+    private final InetSocketAddress sender;
+    private final InetSocketAddress recipient;
+
+    /**
+     * Creates a new instance with the {@link DnsOpCode#QUERY} {@code opCode}.
+     *
+     * @param sender the address of the sender
+     * @param recipient the address of the recipient
+     * @param id the {@code ID} of the DNS query
+     */
+    public DatagramDnsQuery(
+            InetSocketAddress sender, InetSocketAddress recipient, int id) {
+        this(sender, recipient, id, DnsOpCode.QUERY);
+    }
+
+    /**
+     * Creates a new instance.
+     *
+     * @param sender the address of the sender
+     * @param recipient the address of the recipient
+     * @param id the {@code ID} of the DNS query
+     * @param opCode the {@code opCode} of the DNS query
+     */
+    public DatagramDnsQuery(
+            InetSocketAddress sender, InetSocketAddress recipient, int id, DnsOpCode opCode) {
+        super(id, opCode);
+
+        if (recipient == null && sender == null) {
+            throw new NullPointerException("recipient and sender");
+        }
+
+        this.sender = sender;
+        this.recipient = recipient;
+    }
+
+    @Override
+    public DatagramDnsQuery content() {
+        return this;
+    }
+
+    @Override
+    public InetSocketAddress sender() {
+        return sender;
+    }
+
+    @Override
+    public InetSocketAddress recipient() {
+        return recipient;
+    }
+
+    @Override
+    public DatagramDnsQuery setId(int id) {
+        return (DatagramDnsQuery) super.setId(id);
+    }
+
+    @Override
+    public DatagramDnsQuery setOpCode(DnsOpCode opCode) {
+        return (DatagramDnsQuery) super.setOpCode(opCode);
+    }
+
+    @Override
+    public DatagramDnsQuery setRecursionDesired(boolean recursionDesired) {
+        return (DatagramDnsQuery) super.setRecursionDesired(recursionDesired);
+    }
+
+    @Override
+    public DatagramDnsQuery setZ(int z) {
+        return (DatagramDnsQuery) super.setZ(z);
+    }
+
+    @Override
+    public DatagramDnsQuery setRecord(DnsSection section, DnsRecord record) {
+        return (DatagramDnsQuery) super.setRecord(section, record);
+    }
+
+    @Override
+    public DatagramDnsQuery addRecord(DnsSection section, DnsRecord record) {
+        return (DatagramDnsQuery) super.addRecord(section, record);
+    }
+
+    @Override
+    public DatagramDnsQuery addRecord(DnsSection section, int index, DnsRecord record) {
+        return (DatagramDnsQuery) super.addRecord(section, index, record);
+    }
+
+    @Override
+    public DatagramDnsQuery clear(DnsSection section) {
+        return (DatagramDnsQuery) super.clear(section);
+    }
+
+    @Override
+    public DatagramDnsQuery clear() {
+        return (DatagramDnsQuery) super.clear();
+    }
+
+    @Override
+    public DatagramDnsQuery touch() {
+        return (DatagramDnsQuery) super.touch();
+    }
+
+    @Override
+    public DatagramDnsQuery touch(Object hint) {
+        return (DatagramDnsQuery) super.touch(hint);
+    }
+
+    @Override
+    public DatagramDnsQuery retain() {
+        return (DatagramDnsQuery) super.retain();
+    }
+
+    @Override
+    public DatagramDnsQuery retain(int increment) {
+        return (DatagramDnsQuery) super.retain(increment);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (!super.equals(obj)) {
+            return false;
+        }
+
+        if (!(obj instanceof AddressedEnvelope)) {
+            return false;
+        }
+
+        @SuppressWarnings("unchecked")
+        final AddressedEnvelope<?, SocketAddress> that = (AddressedEnvelope<?, SocketAddress>) obj;
+        if (sender() == null) {
+            if (that.sender() != null) {
+                return false;
+            }
+        } else if (!sender().equals(that.sender())) {
+            return false;
+        }
+
+        if (recipient() == null) {
+            if (that.recipient() != null) {
+                return false;
+            }
+        } else if (!recipient().equals(that.recipient())) {
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public int hashCode() {
+        int hashCode = super.hashCode();
+        if (sender() != null) {
+            hashCode = hashCode * 31 + sender().hashCode();
+        }
+        if (recipient() != null) {
+            hashCode = hashCode * 31 + recipient().hashCode();
+        }
+        return hashCode;
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DatagramDnsQueryEncoder.java

@@ -0,0 +1,120 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.AddressedEnvelope;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.socket.DatagramPacket;
+import io.netty.handler.codec.MessageToMessageEncoder;
+
+import java.net.InetSocketAddress;
+import java.util.List;
+
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+
+/**
+ * Encodes a {@link DatagramDnsQuery} (or an {@link AddressedEnvelope} of {@link DnsQuery}} into a
+ * {@link DatagramPacket}.
+ */
+@ChannelHandler.Sharable
+public class DatagramDnsQueryEncoder extends MessageToMessageEncoder<AddressedEnvelope<DnsQuery, InetSocketAddress>> {
+
+    private final DnsRecordEncoder recordEncoder;
+
+    /**
+     * Creates a new encoder with {@linkplain DnsRecordEncoder#DEFAULT the default record encoder}.
+     */
+    public DatagramDnsQueryEncoder() {
+        this(DnsRecordEncoder.DEFAULT);
+    }
+
+    /**
+     * Creates a new encoder with the specified {@code recordEncoder}.
+     */
+    public DatagramDnsQueryEncoder(DnsRecordEncoder recordEncoder) {
+        this.recordEncoder = checkNotNull(recordEncoder, "recordEncoder");
+    }
+
+    @Override
+    protected void encode(
+            ChannelHandlerContext ctx,
+            AddressedEnvelope<DnsQuery, InetSocketAddress> in, List<Object> out) throws Exception {
+
+        final InetSocketAddress recipient = in.recipient();
+        final DnsQuery query = in.content();
+        final ByteBuf buf = allocateBuffer(ctx, in);
+
+        boolean success = false;
+        try {
+            encodeHeader(query, buf);
+            encodeQuestions(query, buf);
+            encodeRecords(query, DnsSection.ADDITIONAL, buf);
+            success = true;
+        } finally {
+            if (!success) {
+                buf.release();
+            }
+        }
+
+        out.add(new DatagramPacket(buf, recipient, null));
+    }
+
+    /**
+     * Allocate a {@link ByteBuf} which will be used for constructing a datagram packet.
+     * Sub-classes may override this method to return a {@link ByteBuf} with a perfect matching initial capacity.
+     */
+    protected ByteBuf allocateBuffer(
+            ChannelHandlerContext ctx,
+            @SuppressWarnings("unused") AddressedEnvelope<DnsQuery, InetSocketAddress> msg) throws Exception {
+        return ctx.alloc().ioBuffer(1024);
+    }
+
+    /**
+     * Encodes the header that is always 12 bytes long.
+     *
+     * @param query
+     *            the query header being encoded
+     * @param buf
+     *            the buffer the encoded data should be written to
+     */
+    private static void encodeHeader(DnsQuery query, ByteBuf buf) {
+        buf.writeShort(query.id());
+        int flags = 0;
+        flags |= (query.opCode().byteValue() & 0xFF) << 14;
+        flags |= query.isRecursionDesired()? 1 << 8 : 0;
+        buf.writeShort(flags);
+        buf.writeShort(query.count(DnsSection.QUESTION));
+        buf.writeShort(0); // answerCount
+        buf.writeShort(0); // authorityResourceCount
+        buf.writeShort(query.count(DnsSection.ADDITIONAL));
+    }
+
+    private void encodeQuestions(DnsQuery query, ByteBuf buf) throws Exception {
+        final int count = query.count(DnsSection.QUESTION);
+        for (int i = 0; i < count; i ++) {
+            recordEncoder.encodeQuestion((DnsQuestion) query.recordAt(DnsSection.QUESTION, i), buf);
+        }
+    }
+
+    private void encodeRecords(DnsQuery query, DnsSection section, ByteBuf buf) throws Exception {
+        final int count = query.count(section);
+        for (int i = 0; i < count; i ++) {
+            recordEncoder.encodeRecord(query.recordAt(section, i), buf);
+        }
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DatagramDnsResponse.java

@@ -0,0 +1,224 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.channel.AddressedEnvelope;
+
+import java.net.InetSocketAddress;
+import java.net.SocketAddress;
+
+/**
+ * A {@link DnsResponse} implementation for UDP/IP.
+ */
+public class DatagramDnsResponse extends DefaultDnsResponse
+        implements AddressedEnvelope<DatagramDnsResponse, InetSocketAddress> {
+
+    private final InetSocketAddress sender;
+    private final InetSocketAddress recipient;
+
+    /**
+     * Creates a new instance with the {@link DnsOpCode#QUERY} {@code opCode} and
+     * the {@link DnsResponseCode#NOERROR} {@code RCODE}.
+     *
+     * @param sender the address of the sender
+     * @param recipient the address of the recipient
+     * @param id the {@code ID} of the DNS response
+     */
+    public DatagramDnsResponse(InetSocketAddress sender, InetSocketAddress recipient, int id) {
+        this(sender, recipient, id, DnsOpCode.QUERY, DnsResponseCode.NOERROR);
+    }
+
+    /**
+     * Creates a new instance with the {@link DnsResponseCode#NOERROR} responseCode.
+     *
+     * @param sender the address of the sender
+     * @param recipient the address of the recipient
+     * @param id the {@code ID} of the DNS response
+     * @param opCode the {@code opCode} of the DNS response
+     */
+    public DatagramDnsResponse(InetSocketAddress sender, InetSocketAddress recipient, int id, DnsOpCode opCode) {
+        this(sender, recipient, id, opCode, DnsResponseCode.NOERROR);
+    }
+
+    /**
+     * Creates a new instance.
+     *
+     * @param sender the address of the sender
+     * @param recipient the address of the recipient
+     * @param id the {@code ID} of the DNS response
+     * @param opCode the {@code opCode} of the DNS response
+     * @param responseCode the {@code RCODE} of the DNS response
+     */
+    public DatagramDnsResponse(
+            InetSocketAddress sender, InetSocketAddress recipient,
+            int id, DnsOpCode opCode, DnsResponseCode responseCode) {
+        super(id, opCode, responseCode);
+
+        if (recipient == null && sender == null) {
+            throw new NullPointerException("recipient and sender");
+        }
+
+        this.sender = sender;
+        this.recipient = recipient;
+    }
+
+    @Override
+    public DatagramDnsResponse content() {
+        return this;
+    }
+
+    @Override
+    public InetSocketAddress sender() {
+        return sender;
+    }
+
+    @Override
+    public InetSocketAddress recipient() {
+        return recipient;
+    }
+
+    @Override
+    public DatagramDnsResponse setAuthoritativeAnswer(boolean authoritativeAnswer) {
+        return (DatagramDnsResponse) super.setAuthoritativeAnswer(authoritativeAnswer);
+    }
+
+    @Override
+    public DatagramDnsResponse setTruncated(boolean truncated) {
+        return (DatagramDnsResponse) super.setTruncated(truncated);
+    }
+
+    @Override
+    public DatagramDnsResponse setRecursionAvailable(boolean recursionAvailable) {
+        return (DatagramDnsResponse) super.setRecursionAvailable(recursionAvailable);
+    }
+
+    @Override
+    public DatagramDnsResponse setCode(DnsResponseCode code) {
+        return (DatagramDnsResponse) super.setCode(code);
+    }
+
+    @Override
+    public DatagramDnsResponse setId(int id) {
+        return (DatagramDnsResponse) super.setId(id);
+    }
+
+    @Override
+    public DatagramDnsResponse setOpCode(DnsOpCode opCode) {
+        return (DatagramDnsResponse) super.setOpCode(opCode);
+    }
+
+    @Override
+    public DatagramDnsResponse setRecursionDesired(boolean recursionDesired) {
+        return (DatagramDnsResponse) super.setRecursionDesired(recursionDesired);
+    }
+
+    @Override
+    public DatagramDnsResponse setZ(int z) {
+        return (DatagramDnsResponse) super.setZ(z);
+    }
+
+    @Override
+    public DatagramDnsResponse setRecord(DnsSection section, DnsRecord record) {
+        return (DatagramDnsResponse) super.setRecord(section, record);
+    }
+
+    @Override
+    public DatagramDnsResponse addRecord(DnsSection section, DnsRecord record) {
+        return (DatagramDnsResponse) super.addRecord(section, record);
+    }
+
+    @Override
+    public DatagramDnsResponse addRecord(DnsSection section, int index, DnsRecord record) {
+        return (DatagramDnsResponse) super.addRecord(section, index, record);
+    }
+
+    @Override
+    public DatagramDnsResponse clear(DnsSection section) {
+        return (DatagramDnsResponse) super.clear(section);
+    }
+
+    @Override
+    public DatagramDnsResponse clear() {
+        return (DatagramDnsResponse) super.clear();
+    }
+
+    @Override
+    public DatagramDnsResponse touch() {
+        return (DatagramDnsResponse) super.touch();
+    }
+
+    @Override
+    public DatagramDnsResponse touch(Object hint) {
+        return (DatagramDnsResponse) super.touch(hint);
+    }
+
+    @Override
+    public DatagramDnsResponse retain() {
+        return (DatagramDnsResponse) super.retain();
+    }
+
+    @Override
+    public DatagramDnsResponse retain(int increment) {
+        return (DatagramDnsResponse) super.retain(increment);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (!super.equals(obj)) {
+            return false;
+        }
+
+        if (!(obj instanceof AddressedEnvelope)) {
+            return false;
+        }
+
+        @SuppressWarnings("unchecked")
+        final AddressedEnvelope<?, SocketAddress> that = (AddressedEnvelope<?, SocketAddress>) obj;
+        if (sender() == null) {
+            if (that.sender() != null) {
+                return false;
+            }
+        } else if (!sender().equals(that.sender())) {
+            return false;
+        }
+
+        if (recipient() == null) {
+            if (that.recipient() != null) {
+                return false;
+            }
+        } else if (!recipient().equals(that.recipient())) {
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public int hashCode() {
+        int hashCode = super.hashCode();
+        if (sender() != null) {
+            hashCode = hashCode * 31 + sender().hashCode();
+        }
+        if (recipient() != null) {
+            hashCode = hashCode * 31 + recipient().hashCode();
+        }
+        return hashCode;
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DatagramDnsResponseDecoder.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.socket.DatagramPacket;
+import io.netty.handler.codec.CorruptedFrameException;
+import io.netty.handler.codec.MessageToMessageDecoder;
+
+import java.net.InetSocketAddress;
+import java.util.List;
+
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+
+/**
+ * Decodes a {@link DatagramPacket} into a {@link DatagramDnsResponse}.
+ */
+@ChannelHandler.Sharable
+public class DatagramDnsResponseDecoder extends MessageToMessageDecoder<DatagramPacket> {
+
+    private final DnsRecordDecoder recordDecoder;
+
+    /**
+     * Creates a new decoder with {@linkplain DnsRecordDecoder#DEFAULT the default record decoder}.
+     */
+    public DatagramDnsResponseDecoder() {
+        this(DnsRecordDecoder.DEFAULT);
+    }
+
+    /**
+     * Creates a new decoder with the specified {@code recordDecoder}.
+     */
+    public DatagramDnsResponseDecoder(DnsRecordDecoder recordDecoder) {
+        this.recordDecoder = checkNotNull(recordDecoder, "recordDecoder");
+    }
+
+    @Override
+    protected void decode(ChannelHandlerContext ctx, DatagramPacket packet, List<Object> out) throws Exception {
+        final InetSocketAddress sender = packet.sender();
+        final ByteBuf buf = packet.content();
+
+        final DnsResponse response = newResponse(sender, buf);
+        boolean success = false;
+        try {
+            final int questionCount = buf.readUnsignedShort();
+            final int answerCount = buf.readUnsignedShort();
+            final int authorityRecordCount = buf.readUnsignedShort();
+            final int additionalRecordCount = buf.readUnsignedShort();
+
+            decodeQuestions(response, buf, questionCount);
+            decodeRecords(response, DnsSection.ANSWER, buf, answerCount);
+            decodeRecords(response, DnsSection.AUTHORITY, buf, authorityRecordCount);
+            decodeRecords(response, DnsSection.ADDITIONAL, buf, additionalRecordCount);
+
+            out.add(response);
+            success = true;
+        } finally {
+            if (!success) {
+                response.release();
+            }
+        }
+    }
+
+    private static DnsResponse newResponse(InetSocketAddress sender, ByteBuf buf) {
+        final int id = buf.readUnsignedShort();
+
+        final int flags = buf.readUnsignedShort();
+        if (flags >> 15 == 0) {
+            throw new CorruptedFrameException("not a response");
+        }
+
+        final DnsResponse response = new DatagramDnsResponse(
+                sender, null,
+                id, DnsOpCode.valueOf((byte) (flags >> 11 & 0xf)), DnsResponseCode.valueOf((byte) (flags & 0xf)));
+
+        response.setRecursionDesired((flags >> 8 & 1) == 1);
+        response.setAuthoritativeAnswer((flags >> 10 & 1) == 1);
+        response.setTruncated((flags >> 9 & 1) == 1);
+        response.setRecursionAvailable((flags >> 7 & 1) == 1);
+        response.setZ(flags >> 4 & 0x7);
+        return response;
+    }
+
+    private void decodeQuestions(DnsResponse response, ByteBuf buf, int questionCount) throws Exception {
+        for (int i = questionCount; i > 0; i --) {
+            response.addRecord(DnsSection.QUESTION, recordDecoder.decodeQuestion(buf));
+        }
+    }
+
+    private void decodeRecords(
+            DnsResponse response, DnsSection section, ByteBuf buf, int count) throws Exception {
+        for (int i = count; i > 0; i --) {
+            response.addRecord(section, recordDecoder.decodeRecord(buf));
+        }
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DefaultDnsQuery.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+/**
+ * The default {@link DnsQuery} implementation.
+ */
+public class DefaultDnsQuery extends AbstractDnsMessage implements DnsQuery {
+
+    /**
+     * Creates a new instance with the {@link DnsOpCode#QUERY} {@code opCode}.
+     *
+     * @param id the {@code ID} of the DNS query
+     */
+    public DefaultDnsQuery(int id) {
+        super(id);
+    }
+
+    /**
+     * Creates a new instance.
+     *
+     * @param id the {@code ID} of the DNS query
+     * @param opCode the {@code opCode} of the DNS query
+     */
+    public DefaultDnsQuery(int id, DnsOpCode opCode) {
+        super(id, opCode);
+    }
+
+    @Override
+    public DnsQuery setId(int id) {
+        return (DnsQuery) super.setId(id);
+    }
+
+    @Override
+    public DnsQuery setOpCode(DnsOpCode opCode) {
+        return (DnsQuery) super.setOpCode(opCode);
+    }
+
+    @Override
+    public DnsQuery setRecursionDesired(boolean recursionDesired) {
+        return (DnsQuery) super.setRecursionDesired(recursionDesired);
+    }
+
+    @Override
+    public DnsQuery setZ(int z) {
+        return (DnsQuery) super.setZ(z);
+    }
+
+    @Override
+    public DnsQuery setRecord(DnsSection section, DnsRecord record) {
+        return (DnsQuery) super.setRecord(section, record);
+    }
+
+    @Override
+    public DnsQuery addRecord(DnsSection section, DnsRecord record) {
+        return (DnsQuery) super.addRecord(section, record);
+    }
+
+    @Override
+    public DnsQuery addRecord(DnsSection section, int index, DnsRecord record) {
+        return (DnsQuery) super.addRecord(section, index, record);
+    }
+
+    @Override
+    public DnsQuery clear(DnsSection section) {
+        return (DnsQuery) super.clear(section);
+    }
+
+    @Override
+    public DnsQuery clear() {
+        return (DnsQuery) super.clear();
+    }
+
+    @Override
+    public DnsQuery touch() {
+        return (DnsQuery) super.touch();
+    }
+
+    @Override
+    public DnsQuery touch(Object hint) {
+        return (DnsQuery) super.touch(hint);
+    }
+
+    @Override
+    public DnsQuery retain() {
+        return (DnsQuery) super.retain();
+    }
+
+    @Override
+    public DnsQuery retain(int increment) {
+        return (DnsQuery) super.retain(increment);
+    }
+
+    @Override
+    public String toString() {
+        return DnsMessageUtil.appendQuery(new StringBuilder(128), this).toString();
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DefaultDnsQuestion.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.util.internal.StringUtil;
+
+/**
+ * The default {@link DnsQuestion} implementation.
+ */
+public class DefaultDnsQuestion extends AbstractDnsRecord implements DnsQuestion {
+
+    /**
+     * Creates a new {@link #CLASS_IN IN-class} question.
+     *
+     * @param name the domain name of the DNS question
+     * @param type the type of the DNS question
+     */
+    public DefaultDnsQuestion(String name, DnsRecordType type) {
+        super(name, type, 0);
+    }
+
+    /**
+     * Creates a new question.
+     *
+     * @param name the domain name of the DNS question
+     * @param type the type of the DNS question
+     * @param dnsClass the class of the record, usually one of the following:
+     *                 <ul>
+     *                     <li>{@link #CLASS_IN}</li>
+     *                     <li>{@link #CLASS_CSNET}</li>
+     *                     <li>{@link #CLASS_CHAOS}</li>
+     *                     <li>{@link #CLASS_HESIOD}</li>
+     *                     <li>{@link #CLASS_NONE}</li>
+     *                     <li>{@link #CLASS_ANY}</li>
+     *                 </ul>
+     */
+    public DefaultDnsQuestion(String name, DnsRecordType type, int dnsClass) {
+        super(name, type, dnsClass, 0);
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder buf = new StringBuilder(64);
+
+        buf.append(StringUtil.simpleClassName(this))
+           .append('(')
+           .append(name())
+           .append(' ');
+
+        DnsMessageUtil.appendRecordClass(buf, dnsClass())
+                      .append(' ')
+                      .append(type().name())
+                      .append(')');
+
+        return buf.toString();
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DefaultDnsRawRecord.java

@@ -0,0 +1,143 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.util.internal.StringUtil;
+
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+
+/**
+ * The default {@code DnsRawRecord} implementation.
+ */
+public class DefaultDnsRawRecord extends AbstractDnsRecord implements DnsRawRecord {
+
+    private final ByteBuf content;
+
+    /**
+     * Creates a new {@link #CLASS_IN IN-class} record.
+     *
+     * @param name the domain name
+     * @param type the type of the record
+     * @param timeToLive the TTL value of the record
+     */
+    public DefaultDnsRawRecord(String name, DnsRecordType type, long timeToLive, ByteBuf content) {
+        this(name, type, DnsRecord.CLASS_IN, timeToLive, content);
+    }
+
+    /**
+     * Creates a new record.
+     *
+     * @param name the domain name
+     * @param type the type of the record
+     * @param dnsClass the class of the record, usually one of the following:
+     *                 <ul>
+     *                     <li>{@link #CLASS_IN}</li>
+     *                     <li>{@link #CLASS_CSNET}</li>
+     *                     <li>{@link #CLASS_CHAOS}</li>
+     *                     <li>{@link #CLASS_HESIOD}</li>
+     *                     <li>{@link #CLASS_NONE}</li>
+     *                     <li>{@link #CLASS_ANY}</li>
+     *                 </ul>
+     * @param timeToLive the TTL value of the record
+     */
+    public DefaultDnsRawRecord(
+            String name, DnsRecordType type, int dnsClass, long timeToLive, ByteBuf content) {
+        super(name, type, dnsClass, timeToLive);
+        this.content = checkNotNull(content, "content");
+    }
+
+    @Override
+    public ByteBuf content() {
+        return content;
+    }
+
+    @Override
+    public DnsRawRecord copy() {
+        return new DefaultDnsRawRecord(name(), type(), dnsClass(), timeToLive(), content().copy());
+    }
+
+    @Override
+    public DnsRawRecord duplicate() {
+        return new DefaultDnsRawRecord(name(), type(), dnsClass(), timeToLive(), content().duplicate());
+    }
+
+    @Override
+    public int refCnt() {
+        return content().refCnt();
+    }
+
+    @Override
+    public DnsRawRecord retain() {
+        content().retain();
+        return this;
+    }
+
+    @Override
+    public DnsRawRecord retain(int increment) {
+        content().retain(increment);
+        return this;
+    }
+
+    @Override
+    public boolean release() {
+        return content().release();
+    }
+
+    @Override
+    public boolean release(int decrement) {
+        return content().release(decrement);
+    }
+
+    @Override
+    public DnsRawRecord touch() {
+        content().touch();
+        return this;
+    }
+
+    @Override
+    public DnsRawRecord touch(Object hint) {
+        content().touch(hint);
+        return this;
+    }
+
+    @Override
+    public String toString() {
+        final StringBuilder buf = new StringBuilder(64).append(StringUtil.simpleClassName(this)).append('(');
+        final DnsRecordType type = type();
+        if (type != DnsRecordType.OPT) {
+            buf.append(name().isEmpty()? "<root>" : name())
+               .append(' ')
+               .append(timeToLive())
+               .append(' ');
+
+            DnsMessageUtil.appendRecordClass(buf, dnsClass())
+                          .append(' ')
+                          .append(type.name());
+        } else {
+            buf.append("OPT flags:")
+               .append(timeToLive())
+               .append(" udp:")
+               .append(dnsClass());
+        }
+
+        buf.append(' ')
+           .append(content().readableBytes())
+           .append("B)");
+
+        return buf.toString();
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DefaultDnsRecordDecoder.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.handler.codec.CorruptedFrameException;
+import io.netty.util.CharsetUtil;
+import io.netty.util.internal.StringUtil;
+
+/**
+ * The default {@link DnsRecordDecoder} implementation.
+ *
+ * @see DefaultDnsRecordEncoder
+ */
+public class DefaultDnsRecordDecoder implements DnsRecordDecoder {
+
+    /**
+     * Creates a new instance.
+     */
+    protected DefaultDnsRecordDecoder() { }
+
+    @Override
+    public final DnsQuestion decodeQuestion(ByteBuf in) throws Exception {
+        String name = decodeName(in);
+        DnsRecordType type = DnsRecordType.valueOf(in.readUnsignedShort());
+        int qClass = in.readUnsignedShort();
+        return new DefaultDnsQuestion(name, type, qClass);
+    }
+
+    @Override
+    public final <T extends DnsRecord> T decodeRecord(ByteBuf in) throws Exception {
+        final String name = decodeName(in);
+        final DnsRecordType type = DnsRecordType.valueOf(in.readUnsignedShort());
+        final int aClass = in.readUnsignedShort();
+        final long ttl = in.readUnsignedInt();
+        final int length = in.readUnsignedShort();
+        final int offset = in.readerIndex();
+
+        @SuppressWarnings("unchecked")
+        T record = (T) decodeRecord(name, type, aClass, ttl, in, offset, length);
+        in.readerIndex(offset + length);
+        return record;
+    }
+
+    /**
+     * Decodes a record from the information decoded so far by {@link #decodeRecord(ByteBuf)}.
+     *
+     * @param name the domain name of the record
+     * @param type the type of the record
+     * @param dnsClass the class of the record
+     * @param timeToLive the TTL of the record
+     * @param in the {@link ByteBuf} that contains the RDATA
+     * @param offset the start offset of the RDATA in {@code in}
+     * @param length the length of the RDATA
+     *
+     * @return a {@link DnsRawRecord}. Override this method to decode RDATA and return other record implementation.
+     */
+    protected DnsRecord decodeRecord(
+            String name, DnsRecordType type, int dnsClass, long timeToLive,
+            ByteBuf in, int offset, int length) throws Exception {
+
+        return new DefaultDnsRawRecord(
+                name, type, dnsClass, timeToLive, in.duplicate().setIndex(offset, offset + length).retain());
+    }
+
+    /**
+     * Retrieves a domain name given a buffer containing a DNS packet. If the
+     * name contains a pointer, the position of the buffer will be set to
+     * directly after the pointer's index after the name has been read.
+     *
+     * @param in the byte buffer containing the DNS packet
+     * @return the domain name for an entry
+     */
+    protected String decodeName(ByteBuf in) {
+        int position = -1;
+        int checked = 0;
+        final int end = in.writerIndex();
+        final StringBuilder name = new StringBuilder(in.readableBytes() << 1);
+        for (int len = in.readUnsignedByte(); in.isReadable() && len != 0; len = in.readUnsignedByte()) {
+            boolean pointer = (len & 0xc0) == 0xc0;
+            if (pointer) {
+                if (position == -1) {
+                    position = in.readerIndex() + 1;
+                }
+
+                final int next = (len & 0x3f) << 8 | in.readUnsignedByte();
+                if (next >= end) {
+                    throw new CorruptedFrameException("name has an out-of-range pointer");
+                }
+                in.readerIndex(next);
+
+                // check for loops
+                checked += 2;
+                if (checked >= end) {
+                    throw new CorruptedFrameException("name contains a loop.");
+                }
+            } else {
+                name.append(in.toString(in.readerIndex(), len, CharsetUtil.UTF_8)).append('.');
+                in.skipBytes(len);
+            }
+        }
+        if (position != -1) {
+            in.readerIndex(position);
+        }
+        if (name.length() == 0) {
+            return StringUtil.EMPTY_STRING;
+        }
+
+        return name.substring(0, name.length() - 1);
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DefaultDnsRecordEncoder.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
+import io.netty.handler.codec.UnsupportedMessageTypeException;
+import io.netty.util.internal.StringUtil;
+
+/**
+ * The default {@link DnsRecordEncoder} implementation.
+ *
+ * @see DefaultDnsRecordDecoder
+ */
+public class DefaultDnsRecordEncoder implements DnsRecordEncoder {
+
+    /**
+     * Creates a new instance.
+     */
+    protected DefaultDnsRecordEncoder() { }
+
+    @Override
+    public final void encodeQuestion(DnsQuestion question, ByteBuf out) throws Exception {
+        encodeName(question.name(), out);
+        out.writeShort(question.type().intValue());
+        out.writeShort(question.dnsClass());
+    }
+
+    @Override
+    public void encodeRecord(DnsRecord record, ByteBuf out) throws Exception {
+        if (record instanceof DnsQuestion) {
+            encodeQuestion((DnsQuestion) record, out);
+        } else if (record instanceof DnsRawRecord) {
+            encodeRawRecord((DnsRawRecord) record, out);
+        } else {
+            throw new UnsupportedMessageTypeException(StringUtil.simpleClassName(record));
+        }
+    }
+
+    private void encodeRawRecord(DnsRawRecord record, ByteBuf out) throws Exception {
+        encodeName(record.name(), out);
+
+        out.writeShort(record.type().intValue());
+        out.writeShort(record.dnsClass());
+        out.writeInt((int) record.timeToLive());
+
+        ByteBuf content = record.content();
+        int contentLen = content.readableBytes();
+
+        out.writeShort(contentLen);
+        out.writeBytes(content, content.readerIndex(), contentLen);
+    }
+
+    protected void encodeName(String name, ByteBuf buf) throws Exception {
+        String[] parts = StringUtil.split(name, '.');
+        for (String part: parts) {
+            final int partLen = part.length();
+            if (partLen == 0) {
+                continue;
+            }
+            buf.writeByte(partLen);
+            ByteBufUtil.writeAscii(buf, part);
+        }
+        buf.writeByte(0); // marks end of name field
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DefaultDnsResponse.java

@@ -0,0 +1,175 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+
+/**
+ * The default {@link DnsResponse} implementation.
+ */
+public class DefaultDnsResponse extends AbstractDnsMessage implements DnsResponse {
+
+    private boolean authoritativeAnswer;
+    private boolean truncated;
+    private boolean recursionAvailable;
+    private DnsResponseCode code;
+
+    /**
+     * Creates a new instance with the {@link DnsOpCode#QUERY} {@code opCode} and
+     * the {@link DnsResponseCode#NOERROR} {@code RCODE}.
+     *
+     * @param id the {@code ID} of the DNS response
+     */
+    public DefaultDnsResponse(int id) {
+        this(id, DnsOpCode.QUERY, DnsResponseCode.NOERROR);
+    }
+
+    /**
+     * Creates a new instance with the {@link DnsResponseCode#NOERROR} {@code RCODE}.
+     *
+     * @param id the {@code ID} of the DNS response
+     * @param opCode the {@code opCode} of the DNS response
+     */
+    public DefaultDnsResponse(int id, DnsOpCode opCode) {
+        this(id, opCode, DnsResponseCode.NOERROR);
+    }
+
+    /**
+     * Creates a new instance.
+     *
+     * @param id the {@code ID} of the DNS response
+     * @param opCode the {@code opCode} of the DNS response
+     * @param code the {@code RCODE} of the DNS response
+     */
+    public DefaultDnsResponse(int id, DnsOpCode opCode, DnsResponseCode code) {
+        super(id, opCode);
+        setCode(code);
+    }
+
+    @Override
+    public boolean isAuthoritativeAnswer() {
+        return authoritativeAnswer;
+    }
+
+    @Override
+    public DnsResponse setAuthoritativeAnswer(boolean authoritativeAnswer) {
+        this.authoritativeAnswer = authoritativeAnswer;
+        return this;
+    }
+
+    @Override
+    public boolean isTruncated() {
+        return truncated;
+    }
+
+    @Override
+    public DnsResponse setTruncated(boolean truncated) {
+        this.truncated = truncated;
+        return this;
+    }
+
+    @Override
+    public boolean isRecursionAvailable() {
+        return recursionAvailable;
+    }
+
+    @Override
+    public DnsResponse setRecursionAvailable(boolean recursionAvailable) {
+        this.recursionAvailable = recursionAvailable;
+        return this;
+    }
+
+    @Override
+    public DnsResponseCode code() {
+        return code;
+    }
+
+    @Override
+    public DnsResponse setCode(DnsResponseCode code) {
+        this.code = checkNotNull(code, "code");
+        return this;
+    }
+
+    @Override
+    public DnsResponse setId(int id) {
+        return (DnsResponse) super.setId(id);
+    }
+
+    @Override
+    public DnsResponse setOpCode(DnsOpCode opCode) {
+        return (DnsResponse) super.setOpCode(opCode);
+    }
+
+    @Override
+    public DnsResponse setRecursionDesired(boolean recursionDesired) {
+        return (DnsResponse) super.setRecursionDesired(recursionDesired);
+    }
+
+    @Override
+    public DnsResponse setZ(int z) {
+        return (DnsResponse) super.setZ(z);
+    }
+
+    @Override
+    public DnsResponse setRecord(DnsSection section, DnsRecord record) {
+        return (DnsResponse) super.setRecord(section, record);
+    }
+
+    @Override
+    public DnsResponse addRecord(DnsSection section, DnsRecord record) {
+        return (DnsResponse) super.addRecord(section, record);
+    }
+
+    @Override
+    public DnsResponse addRecord(DnsSection section, int index, DnsRecord record) {
+        return (DnsResponse) super.addRecord(section, index, record);
+    }
+
+    @Override
+    public DnsResponse clear(DnsSection section) {
+        return (DnsResponse) super.clear(section);
+    }
+
+    @Override
+    public DnsResponse clear() {
+        return (DnsResponse) super.clear();
+    }
+
+    @Override
+    public DnsResponse touch() {
+        return (DnsResponse) super.touch();
+    }
+
+    @Override
+    public DnsResponse touch(Object hint) {
+        return (DnsResponse) super.touch(hint);
+    }
+
+    @Override
+    public DnsResponse retain() {
+        return (DnsResponse) super.retain();
+    }
+
+    @Override
+    public DnsResponse retain(int increment) {
+        return (DnsResponse) super.retain(increment);
+    }
+
+    @Override
+    public String toString() {
+        return DnsMessageUtil.appendResponse(new StringBuilder(128), this).toString();
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsClass.java

@@ -1,146 +0,0 @@
-/*
- * Copyright 2014 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.handler.codec.dns;
-
-/**
- * Represents a class field in DNS protocol
- */
-public final class DnsClass implements Comparable<DnsClass> {
-
-    /**
-     * Default class for DNS entries.
-     */
-    public static final DnsClass IN = new DnsClass(0x0001, "IN");
-    public static final DnsClass CSNET = new DnsClass(0x0002, "CSNET");
-    public static final DnsClass CHAOS = new DnsClass(0x0003, "CHAOS");
-    public static final DnsClass HESIOD = new DnsClass(0x0004, "HESIOD");
-    public static final DnsClass NONE = new DnsClass(0x00fe, "NONE");
-    public static final DnsClass ANY = new DnsClass(0x00ff, "ANY");
-
-    private static final String EXPECTED =
-            " (expected: " +
-            IN + '(' + IN.intValue() + "), " +
-            CSNET + '(' + CSNET.intValue() + "), " +
-            CHAOS + '(' + CHAOS.intValue() + "), " +
-            HESIOD + '(' + HESIOD.intValue() + "), " +
-            NONE + '(' + NONE.intValue() + "), " +
-            ANY + '(' + ANY.intValue() + "))";
-
-    public static DnsClass valueOf(String name) {
-        if (IN.name().equals(name)) {
-            return IN;
-        }
-        if (NONE.name().equals(name)) {
-            return NONE;
-        }
-        if (ANY.name().equals(name)) {
-            return ANY;
-        }
-        if (CSNET.name().equals(name)) {
-            return CSNET;
-        }
-        if (CHAOS.name().equals(name)) {
-            return CHAOS;
-        }
-        if (HESIOD.name().equals(name)) {
-            return HESIOD;
-        }
-
-        throw new IllegalArgumentException("name: " + name + EXPECTED);
-    }
-
-    public static DnsClass valueOf(int intValue) {
-        switch (intValue) {
-        case 0x0001:
-            return IN;
-        case 0x0002:
-            return CSNET;
-        case 0x0003:
-            return CHAOS;
-        case 0x0004:
-            return HESIOD;
-        case 0x00fe:
-            return NONE;
-        case 0x00ff:
-            return ANY;
-        default:
-            return new DnsClass(intValue, "UNKNOWN");
-        }
-    }
-
-    /**
-     * Returns an instance of DnsClass for a custom type.
-     *
-     * @param clazz The class
-     * @param name The name
-     */
-    public static DnsClass valueOf(int clazz, String name) {
-        return new DnsClass(clazz, name);
-    }
-
-    /**
-     * The protocol value of this DNS class
-     */
-    private final int intValue;
-
-    /**
-     * The name of this DNS class
-     */
-    private final String name;
-
-    private DnsClass(int intValue, String name) {
-        if ((intValue & 0xffff) != intValue) {
-            throw new IllegalArgumentException("intValue: " + intValue + " (expected: 0 ~ 65535)");
-        }
-
-        this.intValue = intValue;
-        this.name = name;
-    }
-
-    /**
-     * Returns the name of this class as used in bind config files
-     */
-    public String name() {
-        return name;
-    }
-
-    /**
-     * Returns the protocol value represented by this class
-     */
-    public int intValue() {
-        return intValue;
-    }
-
-    @Override
-    public int hashCode() {
-        return intValue;
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        return o instanceof DnsClass && ((DnsClass) o).intValue == intValue;
-    }
-
-    @Override
-    public int compareTo(DnsClass o) {
-        return intValue() - o.intValue();
-    }
-
-    @Override
-    public String toString() {
-        return name;
-    }
-}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsEntry.java

@@ -1,96 +0,0 @@
-/*
- * Copyright 2013 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.handler.codec.dns;
-
-import io.netty.util.internal.StringUtil;
-
-/**
- * A class representing entries in a DNS packet (questions, and all resource
- * records). Contains data shared by entries such as name, type, and class.
- */
-public class DnsEntry {
-
-    private final String name;
-    private final DnsType type;
-    private final DnsClass dnsClass;
-
-    // only allow to extend from same package
-    DnsEntry(String name, DnsType type, DnsClass dnsClass) {
-        if (name == null) {
-            throw new NullPointerException("name");
-        }
-        if (type == null) {
-            throw new NullPointerException("type");
-        }
-        if (dnsClass == null) {
-            throw new NullPointerException("dnsClass");
-        }
-
-        this.name = name;
-        this.type = type;
-        this.dnsClass = dnsClass;
-    }
-
-    /**
-     * Returns the name of this entry (the domain).
-     */
-    public String name() {
-        return name;
-    }
-
-    /**
-     * Returns the type of resource record to be received.
-     */
-    public DnsType type() {
-        return type;
-    }
-
-    /**
-     * Returns the class for this entry. Default is IN (Internet).
-     */
-    public DnsClass dnsClass() {
-        return dnsClass;
-    }
-
-    @Override
-    public int hashCode() {
-        return (name.hashCode() * 31 + type.hashCode()) * 31 + dnsClass.hashCode();
-    }
-
-    @Override
-    public String toString() {
-        return new StringBuilder(128).append(StringUtil.simpleClassName(this))
-                                     .append("(name: ").append(name)
-                                     .append(", type: ").append(type)
-                                     .append(", class: ").append(dnsClass)
-                                     .append(')').toString();
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (!(o instanceof DnsEntry)) {
-            return false;
-        }
-
-        DnsEntry that = (DnsEntry) o;
-        return type().intValue() == that.type().intValue() &&
-               dnsClass().intValue() == that.dnsClass().intValue() &&
-               name().equals(that.name());
-    }
-}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsHeader.java

@@ -1,194 +0,0 @@
-/*
- * Copyright 2013 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.handler.codec.dns;
-
-/**
- * The header super-class which includes information shared by DNS query and
- * response packet headers such as the ID, opcode, and type. The only flag
- * shared by both classes is the flag for desiring recursion.
- */
-public class DnsHeader {
-
-    /**
-     * Message type is query.
-     */
-    public static final int TYPE_QUERY = 0;
-
-    /**
-     * Message type is response.
-     */
-    public static final int TYPE_RESPONSE = 1;
-
-    /**
-     * Message is for a standard query.
-     */
-    public static final int OPCODE_QUERY = 0;
-
-    /**
-     * Message is for an inverse query. <strong>Note: inverse queries have been
-     * obsoleted since RFC 3425, and are not necessarily supported.</strong>
-     */
-    @Deprecated
-    public static final int OPCODE_IQUERY = 1;
-
-    private final DnsMessage parent;
-
-    private boolean recursionDesired;
-    private int opcode;
-    private int id;
-    private int type;
-    private int z;
-
-    // only allow to extend from within the same package
-    DnsHeader(DnsMessage parent) {
-        if (parent == null) {
-            throw new NullPointerException("parent");
-        }
-        this.parent = parent;
-    }
-
-    /**
-     * Returns the number of questions in the {@link DnsMessage}.
-     */
-    public int questionCount() {
-        return parent.questions().size();
-    }
-
-    /**
-     * Returns the number of answer resource records in the {@link DnsMessage}.
-     */
-    public int answerCount() {
-        return parent.answers().size();
-    }
-
-    /**
-     * Returns the number of authority resource records in the
-     * {@link DnsMessage}.
-     */
-    public int authorityResourceCount() {
-        return parent.authorityResources().size();
-    }
-
-    /**
-     * Returns the number of additional resource records in the
-     * {@link DnsMessage}.
-     */
-    public int additionalResourceCount() {
-        return parent.additionalResources().size();
-    }
-
-    /**
-     * Returns {@code true} if a query is to be pursued recursively.
-     */
-    public boolean isRecursionDesired() {
-        return recursionDesired;
-    }
-
-    /**
-     * Returns the 4 bit opcode used for the {@link DnsMessage}.
-     *
-     * @see #OPCODE_QUERY
-     * @see #OPCODE_IQUERY
-     */
-    public int opcode() {
-        return opcode;
-    }
-
-    /**
-     * Returns the type of {@link DnsMessage}.
-     *
-     * @see #TYPE_QUERY
-     */
-    public int type() {
-        return type;
-    }
-
-    /**
-     * Returns the 2 byte unsigned identifier number used for the
-     * {@link DnsMessage}.
-     */
-    public int id() {
-        return id;
-    }
-
-    /**
-     * Sets the opcode for this {@link DnsMessage}.
-     *
-     * @param opcode
-     *            opcode to set
-     * @return the header to allow method chaining
-     */
-    public DnsHeader setOpcode(int opcode) {
-        this.opcode = opcode;
-        return this;
-    }
-
-    /**
-     * Sets whether a name server is directed to pursue a query recursively or
-     * not.
-     *
-     * @param recursionDesired
-     *            if set to {@code true}, pursues query recursively
-     * @return the header to allow method chaining
-     */
-    public DnsHeader setRecursionDesired(boolean recursionDesired) {
-        this.recursionDesired = recursionDesired;
-        return this;
-    }
-
-    /**
-     * Sets the {@link DnsMessage} type.
-     *
-     * @param type
-     *            message type
-     * @return the header to allow method chaining
-     */
-    public DnsHeader setType(int type) {
-        this.type = type;
-        return this;
-    }
-
-    /**
-     * Sets the id for this {@link DnsMessage}.
-     *
-     * @param id
-     *            a unique 2 byte unsigned identifier
-     * @return the header to allow method chaining
-     */
-    public DnsHeader setId(int id) {
-        this.id = id;
-        return this;
-    }
-
-    /**
-     * Returns the 3 bit reserved field 'Z'.
-     */
-    public int z() {
-        return z;
-    }
-
-    /**
-     * Sets the field Z. This field is reserved and should remain as 0 if the
-     * DNS server does not make usage of this field.
-     *
-     * @param z
-     *            the value for the reserved field Z
-     */
-    public DnsHeader setZ(int z) {
-        this.z = z;
-        return this;
-    }
-}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsMessage.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 The Netty Project
+ * Copyright 2015 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -15,225 +15,142 @@
  */
 package io.netty.handler.codec.dns;
 
-import io.netty.util.AbstractReferenceCounted;
+import io.netty.util.ReferenceCounted;
-import io.netty.util.ReferenceCountUtil;
-
-import java.util.Collections;
-import java.util.LinkedList;
-import java.util.List;
 
 /**
- * The message super-class which contains core information concerning DNS
+ * The superclass which contains core information concerning a {@link DnsQuery} and a {@link DnsResponse}.
- * packets, both outgoing and incoming.
  */
-public abstract class DnsMessage extends AbstractReferenceCounted {
+public interface DnsMessage extends ReferenceCounted {
-
-    private List<DnsQuestion> questions;
-    private List<DnsResource> answers;
-    private List<DnsResource> authority;
-    private List<DnsResource> additional;
-
-    private final DnsHeader header;
-
-    // Only allow to extend from same package
-    DnsMessage(int id) {
-        header = newHeader(id);
-    }
 
     /**
-     * Returns the header belonging to this message.
+     * Returns the {@code ID} of this DNS message.
      */
-    public DnsHeader header() {
+    int id();
-        return header;
-    }
 
     /**
-     * Returns a list of all the questions in this message.
+     * Sets the {@code ID} of this DNS message.
      */
-    public List<DnsQuestion> questions() {
+    DnsMessage setId(int id);
-        if (questions == null) {
-            return Collections.emptyList();
-        }
-        return Collections.unmodifiableList(questions);
-    }
 
     /**
-     * Returns a list of all the answer resource records in this message.
+     * Returns the {@code opCode} of this DNS message.
      */
-    public List<DnsResource> answers() {
+    DnsOpCode opCode();
-        if (answers == null) {
-            return Collections.emptyList();
-        }
-        return Collections.unmodifiableList(answers);
-    }
 
     /**
-     * Returns a list of all the authority resource records in this message.
+     * Sets the {@code opCode} of this DNS message.
      */
-    public List<DnsResource> authorityResources() {
+    DnsMessage setOpCode(DnsOpCode opCode);
-        if (authority == null) {
-            return Collections.emptyList();
-        }
-        return Collections.unmodifiableList(authority);
-    }
 
     /**
-     * Returns a list of all the additional resource records in this message.
+     * Returns the {@code RD} (recursion desired} field of this DNS message.
      */
-    public List<DnsResource> additionalResources() {
+    boolean isRecursionDesired();
-        if (additional == null) {
-            return Collections.emptyList();
-        }
-        return Collections.unmodifiableList(additional);
-    }
 
     /**
-     * Adds an answer resource record to this message.
+     * Sets the {@code RD} (recursion desired} field of this DNS message.
+     */
+    DnsMessage setRecursionDesired(boolean recursionDesired);
+
+    /**
+     * Returns the {@code Z} (reserved for future use) field of this DNS message.
+     */
+    int z();
+
+    /**
+     * Sets the {@code Z} (reserved for future use) field of this DNS message.
+     */
+    DnsMessage setZ(int z);
+
+    /**
+     * Returns the number of records in the specified {@code section} of this DNS message.
+     */
+    int count(DnsSection section);
+
+    /**
+     * Returns the number of records in this DNS message.
+     */
+    int count();
+
+    /**
+     * Returns the first record in the specified {@code section} of this DNS message.
+     * When the specified {@code section} is {@link DnsSection#QUESTION}, the type of the returned record is
+     * always {@link DnsQuestion}.
      *
-     * @param answer
+     * @return {@code null} if this message doesn't have any records in the specified {@code section}
-     *            the answer resource record to be added
-     * @return the message to allow method chaining
      */
-    public DnsMessage addAnswer(DnsResource answer) {
+    <T extends DnsRecord> T recordAt(DnsSection section);
-        if (answers == null) {
-            answers = new LinkedList<DnsResource>();
-        }
-        answers.add(answer);
-        return this;
-    }
 
     /**
-     * Adds a question to this message.
+     * Returns the record at the specified {@code index} of the specified {@code section} of this DNS message.
+     * When the specified {@code section} is {@link DnsSection#QUESTION}, the type of the returned record is
+     * always {@link DnsQuestion}.
      *
-     * @param question
+     * @throws IndexOutOfBoundsException if the specified {@code index} is out of bounds
-     *            the question to be added
-     * @return the message to allow method chaining
      */
-    public DnsMessage addQuestion(DnsQuestion question) {
+    <T extends DnsRecord> T recordAt(DnsSection section, int index);
-        if (questions == null) {
-            questions = new LinkedList<DnsQuestion>();
-        }
-        questions.add(question);
-        return this;
-    }
 
     /**
-     * Adds an authority resource record to this message.
+     * Sets the specified {@code section} of this DNS message to the specified {@code record},
-     *
+     * making it a single-record section. When the specified {@code section} is {@link DnsSection#QUESTION},
-     * @param resource
+     * the specified {@code record} must be a {@link DnsQuestion}.
-     *            the authority resource record to be added
-     * @return the message to allow method chaining
      */
-    public DnsMessage addAuthorityResource(DnsResource resource) {
+    DnsMessage setRecord(DnsSection section, DnsRecord record);
-        if (authority == null) {
-            authority = new LinkedList<DnsResource>();
-        }
-        authority.add(resource);
-        return this;
-    }
 
     /**
-     * Adds an additional resource record to this message.
+     * Sets the specified {@code record} at the specified {@code index} of the specified {@code section}
+     * of this DNS message. When the specified {@code section} is {@link DnsSection#QUESTION},
+     * the specified {@code record} must be a {@link DnsQuestion}.
      *
-     * @param resource
+     * @return the old record
-     *            the additional resource record to be added
+     * @throws IndexOutOfBoundsException if the specified {@code index} is out of bounds
-     * @return the message to allow method chaining
      */
-    public DnsMessage addAdditionalResource(DnsResource resource) {
+    <T extends DnsRecord> T setRecord(DnsSection section, int index, DnsRecord record);
-        if (additional == null) {
+
-            additional = new LinkedList<DnsResource>();
+    /**
-        }
+     * Adds the specified {@code record} at the end of the specified {@code section} of this DNS message.
-        additional.add(resource);
+     * When the specified {@code section} is {@link DnsSection#QUESTION}, the specified {@code record}
-        return this;
+     * must be a {@link DnsQuestion}.
-    }
+     */
+    DnsMessage addRecord(DnsSection section, DnsRecord record);
+
+    /**
+     * Adds the specified {@code record} at the specified {@code index} of the specified {@code section}
+     * of this DNS message. When the specified {@code section} is {@link DnsSection#QUESTION}, the specified
+     * {@code record} must be a {@link DnsQuestion}.
+     *
+     * @throws IndexOutOfBoundsException if the specified {@code index} is out of bounds
+     */
+    DnsMessage addRecord(DnsSection section, int index, DnsRecord record);
+
+    /**
+     * Removes the record at the specified {@code index} of the specified {@code section} from this DNS message.
+     * When the specified {@code section} is {@link DnsSection#QUESTION}, the type of the returned record is
+     * always {@link DnsQuestion}.
+     *
+     * @return the removed record
+     */
+    <T extends DnsRecord> T removeRecord(DnsSection section, int index);
+
+    /**
+     * Removes all the records in the specified {@code section} of this DNS message.
+     */
+    DnsMessage clear(DnsSection section);
+
+    /**
+     * Removes all the records in this DNS message.
+     */
+    DnsMessage clear();
 
     @Override
-    protected void deallocate() {
+    DnsMessage touch();
-        // NOOP
-    }
 
     @Override
-    public boolean release() {
+    DnsMessage touch(Object hint);
-        release(questions());
-        release(answers());
-        release(additionalResources());
-        release(authorityResources());
-        return super.release();
-    }
-
-    private static void release(List<?> resources) {
-        for (Object resource: resources) {
-            ReferenceCountUtil.release(resource);
-        }
-    }
 
     @Override
-    public boolean release(int decrement) {
+    DnsMessage retain();
-        release(questions(), decrement);
-        release(answers(), decrement);
-        release(additionalResources(), decrement);
-        release(authorityResources(), decrement);
-        return super.release(decrement);
-    }
-
-    private static void release(List<?> resources, int decrement) {
-        for (Object resource: resources) {
-            ReferenceCountUtil.release(resource, decrement);
-        }
-    }
 
     @Override
-    public DnsMessage touch(Object hint) {
+    DnsMessage retain(int increment);
-        touch(questions(), hint);
-        touch(answers(), hint);
-        touch(additionalResources(), hint);
-        touch(authorityResources(), hint);
-        return this;
-    }
-
-    private static void touch(List<?> resources, Object hint) {
-        for (Object resource: resources) {
-            ReferenceCountUtil.touch(resource, hint);
-        }
-    }
-
-    @Override
-    public DnsMessage retain() {
-        retain(questions());
-        retain(answers());
-        retain(additionalResources());
-        retain(authorityResources());
-        super.retain();
-        return this;
-    }
-
-    private static void retain(List<?> resources) {
-        for (Object resource: resources) {
-            ReferenceCountUtil.retain(resource);
-        }
-    }
-
-    @Override
-    public DnsMessage retain(int increment) {
-        retain(questions(), increment);
-        retain(answers(), increment);
-        retain(additionalResources(), increment);
-        retain(authorityResources(), increment);
-        super.retain(increment);
-        return this;
-    }
-
-    private static void retain(List<?> resources, int increment) {
-        for (Object resource: resources) {
-            ReferenceCountUtil.retain(resource, increment);
-        }
-    }
-
-    @Override
-    public DnsMessage touch() {
-        super.touch();
-        return this;
-    }
-
-    protected abstract DnsHeader newHeader(int id);
 }

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsMessageUtil.java

@@ -0,0 +1,181 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.channel.AddressedEnvelope;
+import io.netty.util.internal.StringUtil;
+
+import java.net.SocketAddress;
+
+/**
+ * Provides some utility methods for DNS message implementations.
+ */
+final class DnsMessageUtil {
+
+    static StringBuilder appendQuery(StringBuilder buf, DnsQuery query) {
+        appendQueryHeader(buf, query);
+        appendAllRecords(buf, query);
+        return buf;
+    }
+
+    static StringBuilder appendResponse(StringBuilder buf, DnsResponse response) {
+        appendResponseHeader(buf, response);
+        appendAllRecords(buf, response);
+        return buf;
+    }
+
+    static StringBuilder appendRecordClass(StringBuilder buf, int dnsClass) {
+        final String name;
+        switch (dnsClass &= 0xFFFF) {
+        case DnsRecord.CLASS_IN:
+            name = "IN";
+            break;
+        case DnsRecord.CLASS_CSNET:
+            name = "CSNET";
+            break;
+        case DnsRecord.CLASS_CHAOS:
+            name = "CHAOS";
+            break;
+        case DnsRecord.CLASS_HESIOD:
+            name = "HESIOD";
+            break;
+        case DnsRecord.CLASS_NONE:
+            name = "NONE";
+            break;
+        case DnsRecord.CLASS_ANY:
+            name = "ANY";
+            break;
+        default:
+            name = null;
+            break;
+        }
+
+        if (name != null) {
+            buf.append(name);
+        } else {
+            buf.append("UNKNOWN(").append(dnsClass).append(')');
+        }
+
+        return buf;
+    }
+
+    private static void appendQueryHeader(StringBuilder buf, DnsQuery msg) {
+        buf.append(StringUtil.simpleClassName(msg))
+           .append('(');
+
+        appendAddresses(buf, msg)
+           .append(msg.id())
+           .append(", ")
+           .append(msg.opCode());
+
+        if (msg.isRecursionDesired()) {
+            buf.append(", RD");
+        }
+        if (msg.z() != 0) {
+            buf.append(", Z: ")
+               .append(msg.z());
+        }
+        buf.append(')');
+    }
+
+    private static void appendResponseHeader(StringBuilder buf, DnsResponse msg) {
+        buf.append(StringUtil.simpleClassName(msg))
+           .append('(');
+
+        appendAddresses(buf, msg)
+           .append(msg.id())
+           .append(", ")
+           .append(msg.opCode())
+           .append(", ")
+           .append(msg.code())
+           .append(',');
+
+        boolean hasComma = true;
+        if (msg.isRecursionDesired()) {
+            hasComma = false;
+            buf.append(" RD");
+        }
+        if (msg.isAuthoritativeAnswer()) {
+            hasComma = false;
+            buf.append(" AA");
+        }
+        if (msg.isTruncated()) {
+            hasComma = false;
+            buf.append(" TC");
+        }
+        if (msg.isRecursionAvailable()) {
+            hasComma = false;
+            buf.append(" RA");
+        }
+        if (msg.z() != 0) {
+            if (!hasComma) {
+                buf.append(',');
+            }
+            buf.append(" Z: ")
+               .append(msg.z());
+        }
+
+        if (hasComma) {
+            buf.setCharAt(buf.length() - 1, ')');
+        } else {
+            buf.append(')');
+        }
+    }
+
+    private static StringBuilder appendAddresses(StringBuilder buf, DnsMessage msg) {
+
+        if (!(msg instanceof AddressedEnvelope)) {
+            return buf;
+        }
+
+        @SuppressWarnings("unchecked")
+        AddressedEnvelope<?, SocketAddress> envelope = (AddressedEnvelope<?, SocketAddress>) msg;
+
+        SocketAddress addr = envelope.sender();
+        if (addr != null) {
+            buf.append("from: ")
+               .append(addr)
+               .append(", ");
+        }
+
+        addr = envelope.recipient();
+        if (addr != null) {
+            buf.append("to: ")
+               .append(addr)
+               .append(", ");
+        }
+
+        return buf;
+    }
+
+    private static void appendAllRecords(StringBuilder buf, DnsMessage msg) {
+        appendRecords(buf, msg, DnsSection.QUESTION);
+        appendRecords(buf, msg, DnsSection.ANSWER);
+        appendRecords(buf, msg, DnsSection.AUTHORITY);
+        appendRecords(buf, msg, DnsSection.ADDITIONAL);
+    }
+
+    private static void appendRecords(StringBuilder buf, DnsMessage message, DnsSection section) {
+        final int count = message.count(section);
+        for (int i = 0; i < count; i ++) {
+            buf.append(StringUtil.NEWLINE)
+               .append(StringUtil.TAB)
+               .append(message.recordAt(section, i));
+        }
+    }
+
+    private DnsMessageUtil() { }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsOpCode.java

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+
+/**
+ * The DNS {@code OpCode} as defined in <a href="https://tools.ietf.org/html/rfc2929">RFC2929</a>.
+ */
+public class DnsOpCode implements Comparable<DnsOpCode> {
+
+    /**
+     * The 'Query' DNS OpCode, as defined in <a href="https://tools.ietf.org/html/rfc1035">RFC1035</a>.
+     */
+    public static final DnsOpCode QUERY = new DnsOpCode(0x00, "QUERY");
+
+    /**
+     * The 'IQuery' DNS OpCode, as defined in <a href="https://tools.ietf.org/html/rfc1035">RFC1035</a>.
+     */
+    public static final DnsOpCode IQUERY = new DnsOpCode(0x01, "IQUERY");
+
+    /**
+     * The 'Status' DNS OpCode, as defined in <a href="https://tools.ietf.org/html/rfc1035">RFC1035</a>.
+     */
+    public static final DnsOpCode STATUS = new DnsOpCode(0x02, "STATUS");
+
+    /**
+     * The 'Notify' DNS OpCode, as defined in <a href="https://tools.ietf.org/html/rfc1996">RFC1996</a>.
+     */
+    public static final DnsOpCode NOTIFY = new DnsOpCode(0x04, "NOTIFY");
+
+    /**
+     * The 'Update' DNS OpCode, as defined in <a href="https://tools.ietf.org/html/rfc2136">RFC2136</a>.
+     */
+    public static final DnsOpCode UPDATE = new DnsOpCode(0x05, "UPDATE");
+
+    /**
+     * Returns the {@link DnsOpCode} instance of the specified byte value.
+     */
+    public static DnsOpCode valueOf(int b) {
+        switch (b) {
+        case 0x00:
+            return QUERY;
+        case 0x01:
+            return IQUERY;
+        case 0x02:
+            return STATUS;
+        case 0x04:
+            return NOTIFY;
+        case 0x05:
+            return UPDATE;
+        }
+
+        return new DnsOpCode(b);
+    }
+
+    private final byte byteValue;
+    private final String name;
+    private String text;
+
+    private DnsOpCode(int byteValue) {
+        this(byteValue, "UNKNOWN");
+    }
+
+    public DnsOpCode(int byteValue, String name) {
+        this.byteValue = (byte) byteValue;
+        this.name = checkNotNull(name, "name");
+    }
+
+    public byte byteValue() {
+        return byteValue;
+    }
+
+    @Override
+    public int hashCode() {
+        return byteValue;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+
+        if (!(obj instanceof DnsOpCode)) {
+            return false;
+        }
+
+        return byteValue == ((DnsOpCode) obj).byteValue;
+    }
+
+    @Override
+    public int compareTo(DnsOpCode o) {
+        return byteValue - o.byteValue;
+    }
+
+    @Override
+    public String toString() {
+        String text = this.text;
+        if (text == null) {
+            this.text = text = name + '(' + (byteValue & 0xFF) + ')';
+        }
+        return text;
+    }
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsQuery.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 The Netty Project
+ * Copyright 2015 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -15,89 +15,46 @@
  */
 package io.netty.handler.codec.dns;
 
-import java.net.InetSocketAddress;
-
 /**
- * A DNS query packet which is sent to a server to receive a DNS response packet
+ * A DNS query message.
- * with information answering a DnsQuery's questions.
  */
-public class DnsQuery extends DnsMessage {
+public interface DnsQuery extends DnsMessage {
-
+    @Override
-    private final InetSocketAddress recipient;
+    DnsQuery setId(int id);
-
-    /**
-     * Constructs a DNS query. By default recursion will be toggled on.
-     */
-    public DnsQuery(int id, InetSocketAddress recipient) {
-        super(id);
-        if (recipient == null) {
-            throw new NullPointerException("recipient");
-        }
-        this.recipient = recipient;
-    }
-
-    /**
-     * Return the {@link InetSocketAddress} of the recipient of the {@link DnsQuery}
-     */
-    public InetSocketAddress recipient() {
-        return recipient;
-    }
 
     @Override
-    public DnsQuery addAnswer(DnsResource answer) {
+    DnsQuery setOpCode(DnsOpCode opCode);
-        super.addAnswer(answer);
-        return this;
-    }
 
     @Override
-    public DnsQuery addQuestion(DnsQuestion question) {
+    DnsQuery setRecursionDesired(boolean recursionDesired);
-        super.addQuestion(question);
-        return this;
-    }
 
     @Override
-    public DnsQuery addAuthorityResource(DnsResource resource) {
+    DnsQuery setZ(int z);
-        super.addAuthorityResource(resource);
-        return this;
-    }
 
     @Override
-    public DnsQuery addAdditionalResource(DnsResource resource) {
+    DnsQuery setRecord(DnsSection section, DnsRecord record);
-        super.addAdditionalResource(resource);
-        return this;
-    }
 
     @Override
-    public DnsQuery touch(Object hint) {
+    DnsQuery addRecord(DnsSection section, DnsRecord record);
-        super.touch(hint);
-        return this;
-    }
 
     @Override
-    public DnsQuery retain() {
+    DnsQuery addRecord(DnsSection section, int index, DnsRecord record);
-        super.retain();
-        return this;
-    }
 
     @Override
-    public DnsQuery retain(int increment) {
+    DnsQuery clear(DnsSection section);
-        super.retain(increment);
-        return this;
-    }
 
     @Override
-    public DnsQuery touch() {
+    DnsQuery clear();
-        super.touch();
-        return this;
-    }
 
     @Override
-    public DnsQueryHeader header() {
+    DnsQuery touch();
-        return (DnsQueryHeader) super.header();
-    }
 
     @Override
-    protected DnsQueryHeader newHeader(int id) {
+    DnsQuery touch(Object hint);
-        return new DnsQueryHeader(this, id);
+
-    }
+    @Override
+    DnsQuery retain();
+
+    @Override
+    DnsQuery retain(int increment);
 }

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsQueryEncoder.java

@@ -1,116 +0,0 @@
-/*
- * Copyright 2013 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.handler.codec.dns;
-
-import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelHandler;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.socket.DatagramPacket;
-import io.netty.handler.codec.MessageToMessageEncoder;
-import io.netty.util.CharsetUtil;
-import io.netty.util.internal.StringUtil;
-
-import java.nio.charset.Charset;
-import java.util.List;
-
-/**
- * DnsQueryEncoder accepts {@link DnsQuery} and encodes to {@link ByteBuf}. This
- * class also contains methods for encoding parts of DnsQuery's such as the
- * header and questions.
- */
-@ChannelHandler.Sharable
-public class DnsQueryEncoder extends MessageToMessageEncoder<DnsQuery> {
-
-    @Override
-    protected void encode(ChannelHandlerContext ctx, DnsQuery query, List<Object> out) throws Exception {
-        ByteBuf buf = ctx.alloc().buffer();
-        encodeHeader(query.header(), buf);
-        List<DnsQuestion> questions = query.questions();
-        for (DnsQuestion question : questions) {
-            encodeQuestion(question, CharsetUtil.US_ASCII, buf);
-        }
-        for (DnsResource resource: query.additionalResources()) {
-            encodeResource(resource, CharsetUtil.US_ASCII, buf);
-        }
-        out.add(new DatagramPacket(buf, query.recipient(), null));
-    }
-
-    /**
-     * Encodes the information in a {@link DnsHeader} and writes it to the
-     * specified {@link ByteBuf}. The header is always 12 bytes long.
-     *
-     * @param header
-     *            the query header being encoded
-     * @param buf
-     *            the buffer the encoded data should be written to
-     */
-    private static void encodeHeader(DnsHeader header, ByteBuf buf) {
-        buf.writeShort(header.id());
-        int flags = 0;
-        flags |= header.type() << 15;
-        flags |= header.opcode() << 14;
-        flags |= header.isRecursionDesired() ? 1 << 8 : 0;
-        buf.writeShort(flags);
-        buf.writeShort(header.questionCount());
-        buf.writeShort(0); // answerCount
-        buf.writeShort(0); // authorityResourceCount
-        buf.writeShort(header.additionalResourceCount());
-    }
-
-    /**
-     * Encodes the information in a {@link DnsQuestion} and writes it to the
-     * specified {@link ByteBuf}.
-     *
-     * @param question
-     *            the question being encoded
-     * @param charset
-     *            charset names are encoded in
-     * @param buf
-     *            the buffer the encoded data should be written to
-     */
-    private static void encodeQuestion(DnsQuestion question, Charset charset, ByteBuf buf) {
-        encodeName(question.name(), charset, buf);
-        buf.writeShort(question.type().intValue());
-        buf.writeShort(question.dnsClass().intValue());
-    }
-
-    private static void encodeResource(DnsResource resource, Charset charset, ByteBuf buf) {
-        encodeName(resource.name(), charset, buf);
-
-        buf.writeShort(resource.type().intValue());
-        buf.writeShort(resource.dnsClass().intValue());
-        buf.writeInt((int) resource.timeToLive());
-
-        ByteBuf content = resource.content();
-        int contentLen = content.readableBytes();
-
-        buf.writeShort(contentLen);
-        buf.writeBytes(content, content.readerIndex(), contentLen);
-    }
-
-    private static void encodeName(String name, Charset charset, ByteBuf buf) {
-        String[] parts = StringUtil.split(name, '.');
-        for (String part: parts) {
-            final int partLen = part.length();
-            if (partLen == 0) {
-                continue;
-            }
-            buf.writeByte(partLen);
-            buf.writeBytes(part.getBytes(charset));
-        }
-        buf.writeByte(0); // marks end of name field
-    }
-}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsQueryHeader.java

@@ -1,84 +0,0 @@
-/*
- * Copyright 2013 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.handler.codec.dns;
-
-/**
- * The DNS query header class which is used to represent the 12 byte header in a
- * {@link DnsQuery}.
- */
-public final class DnsQueryHeader extends DnsHeader {
-
-    /**
-     * Constructor for a DNS packet query header. The id is user generated and
-     * will be replicated in the response packet by the server.
-     *
-     * @param parent the {@link DnsMessage} this header belongs to
-     * @param id     a 2 bit unsigned identification number for this query
-     */
-    public DnsQueryHeader(DnsMessage parent, int id) {
-        super(parent);
-        setId(id);
-        setRecursionDesired(true);
-    }
-
-    /**
-     * Returns the {@link DnsMessage} type. This will always return
-     * {@code TYPE_QUERY}.
-     */
-    @Override
-    public int type() {
-        return TYPE_QUERY;
-    }
-
-    /**
-     * Sets the {@link DnsHeader} type. Must be {@code TYPE_RESPONSE}.
-     *
-     * @param type message type
-     * @return the header to allow method chaining
-     */
-    @Override
-    public DnsQueryHeader setType(int type) {
-        if (type != TYPE_QUERY) {
-            throw new IllegalArgumentException("type cannot be anything but TYPE_QUERY (0) for a query header.");
-        }
-        super.setType(type);
-        return this;
-    }
-
-    @Override
-    public DnsQueryHeader setId(int id) {
-        super.setId(id);
-        return this;
-    }
-
-    @Override
-    public DnsQueryHeader setRecursionDesired(boolean recursionDesired) {
-        super.setRecursionDesired(recursionDesired);
-        return this;
-    }
-
-    @Override
-    public DnsQueryHeader setOpcode(int opcode) {
-        super.setOpcode(opcode);
-        return this;
-    }
-
-    @Override
-    public DnsQueryHeader setZ(int z) {
-        super.setZ(z);
-        return this;
-    }
-}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsQuestion.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 The Netty Project
+ * Copyright 2015 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -15,58 +15,13 @@
  */
 package io.netty.handler.codec.dns;
 
-import static io.netty.handler.codec.dns.DnsClass.IN;
-
 /**
- * The DNS question class which represents a question being sent to a server via
+ * A DNS question.
- * a query, or the question being duplicated and sent back in a response.
- * Usually a message contains a single question, and DNS servers often don't
- * support multiple questions in a single query.
  */
-public final class DnsQuestion extends DnsEntry {
+public interface DnsQuestion extends DnsRecord {
-
     /**
-     * Constructs a question with the default class IN (Internet).
+     * An unused property. This method will always return {@code 0}.
-     *
-     * @param name
-     *            the domain name being queried i.e. "www.example.com"
-     * @param type
-     *            the question type, which represents the type of
-     *            {@link DnsResource} record that should be returned
      */
-    public DnsQuestion(String name, DnsType type) {
-        this(name, type, IN);
-    }
-
-    /**
-     * Constructs a question with the given class.
-     *
-     * @param name
-     *            the domain name being queried i.e. "www.example.com"
-     * @param type
-     *            the question type, which represents the type of
-     *            {@link DnsResource} record that should be returned
-     * @param qClass
-     *            the class of a DNS record
-     */
-    public DnsQuestion(String name, DnsType type, DnsClass qClass) {
-        super(name, type, qClass);
-
-        if (name.isEmpty()) {
-            throw new IllegalArgumentException("name must not be left blank.");
-        }
-    }
-
     @Override
-    public boolean equals(Object other) {
+    long timeToLive();
-        if (!(other instanceof DnsQuestion)) {
-            return false;
-        }
-        return super.equals(other);
-    }
-
-    @Override
-    public int hashCode() {
-        return super.hashCode();
-    }
 }

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsRawRecord.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.buffer.ByteBufHolder;
+
+/**
+ * A generic {@link DnsRecord} that contains an undecoded {@code RDATA}.
+ */
+public interface DnsRawRecord extends DnsRecord, ByteBufHolder {
+    @Override
+    DnsRawRecord copy();
+
+    @Override
+    DnsRawRecord duplicate();
+
+    @Override
+    DnsRawRecord retain();
+
+    @Override
+    DnsRawRecord retain(int increment);
+
+    @Override
+    DnsRawRecord touch();
+
+    @Override
+    DnsRawRecord touch(Object hint);
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsRecord.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+/**
+ * A DNS resource record.
+ */
+public interface DnsRecord {
+
+    /**
+     * DNS resource record class: {@code IN}
+     */
+    int CLASS_IN = 0x0001;
+
+    /**
+     * DNS resource record class: {@code CSNET}
+     */
+    int CLASS_CSNET = 0x0002;
+
+    /**
+     * DNS resource record class: {@code CHAOS}
+     */
+    int CLASS_CHAOS = 0x0003;
+
+    /**
+     * DNS resource record class: {@code HESIOD}
+     */
+    int CLASS_HESIOD = 0x0004;
+
+    /**
+     * DNS resource record class: {@code NONE}
+     */
+    int CLASS_NONE = 0x00fe;
+
+    /**
+     * DNS resource record class: {@code ANY}
+     */
+    int CLASS_ANY = 0x00ff;
+
+    /**
+     * Returns the name of this resource record.
+     */
+    String name();
+
+    /**
+     * Returns the type of this resource record.
+     */
+    DnsRecordType type();
+
+    /**
+     * Returns the class of this resource record.
+     *
+     * @return the class value, usually one of the following:
+     *         <ul>
+     *             <li>{@link #CLASS_IN}</li>
+     *             <li>{@link #CLASS_CSNET}</li>
+     *             <li>{@link #CLASS_CHAOS}</li>
+     *             <li>{@link #CLASS_HESIOD}</li>
+     *             <li>{@link #CLASS_NONE}</li>
+     *             <li>{@link #CLASS_ANY}</li>
+     *         </ul>
+     */
+    int dnsClass();
+
+    /**
+     * Returns the time to live after reading for this resource record.
+     */
+    long timeToLive();
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsRecordDecoder.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.buffer.ByteBuf;
+
+/**
+ * Decodes a DNS record into its object representation.
+ *
+ * @see DatagramDnsResponseDecoder
+ */
+public interface DnsRecordDecoder {
+
+    DnsRecordDecoder DEFAULT = new DefaultDnsRecordDecoder();
+
+    /**
+     * Decodes a DNS question into its object representation.
+     *
+     * @param in the input buffer which contains a DNS question at its reader index
+     */
+    DnsQuestion decodeQuestion(ByteBuf in) throws Exception;
+
+    /**
+     * Decodes a DNS record into its object representation.
+     *
+     * @param in the input buffer which contains a DNS record at its reader index
+     */
+    <T extends DnsRecord> T decodeRecord(ByteBuf in) throws Exception;
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsRecordEncoder.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+import io.netty.buffer.ByteBuf;
+
+/**
+ * Encodes a {@link DnsRecord} into binary representation.
+ *
+ * @see DatagramDnsQueryEncoder
+ */
+public interface DnsRecordEncoder {
+
+    DnsRecordEncoder DEFAULT = new DefaultDnsRecordEncoder();
+
+    /**
+     * Encodes a {@link DnsQuestion}.
+     *
+     * @param out the output buffer where the encoded question will be written to
+     */
+    void encodeQuestion(DnsQuestion question, ByteBuf out) throws Exception;
+
+    /**
+     * Encodes a {@link DnsRecord}.
+     *
+     * @param out the output buffer where the encoded record will be written to
+     */
+    void encodeRecord(DnsRecord record, ByteBuf out) throws Exception;
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsRecordType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 The Netty Project
+ * Copyright 2015 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -16,32 +16,33 @@
 package io.netty.handler.codec.dns;
 
 import io.netty.util.collection.IntObjectHashMap;
+
 import java.util.HashMap;
 import java.util.Map;
 
 /**
  * Represents a DNS record type.
  */
-public final class DnsType implements Comparable<DnsType> {
+public class DnsRecordType implements Comparable<DnsRecordType> {
 
     /**
      * Address record RFC 1035 Returns a 32-bit IPv4 address, most commonly used
      * to map hostnames to an IP address of the host, but also used for DNSBLs,
      * storing subnet masks in RFC 1101, etc.
      */
-    public static final DnsType A = new DnsType(0x0001, "A");
+    public static final DnsRecordType A = new DnsRecordType(0x0001, "A");
 
     /**
      * Name server record RFC 1035 Delegates a DNS zone to use the given
      * authoritative name servers
      */
-    public static final DnsType NS = new DnsType(0x0002, "NS");
+    public static final DnsRecordType NS = new DnsRecordType(0x0002, "NS");
 
     /**
      * Canonical name record RFC 1035 Alias of one name to another: the DNS
      * lookup will continue by retrying the lookup with the new name.
      */
-    public static final DnsType CNAME = new DnsType(0x0005, "CNAME");
+    public static final DnsRecordType CNAME = new DnsRecordType(0x0005, "CNAME");
 
     /**
      * Start of [a zone of] authority record RFC 1035 and RFC 2308 Specifies
@@ -49,7 +50,7 @@ public final class DnsType implements Comparable<DnsType> {
      * server, the email of the domain administrator, the domain serial number,
      * and several timers relating to refreshing the zone.
      */
-    public static final DnsType SOA = new DnsType(0x0006, "SOA");
+    public static final DnsRecordType SOA = new DnsRecordType(0x0006, "SOA");
 
     /**
      * Pointer record RFC 1035 Pointer to a canonical name. Unlike a CNAME, DNS
@@ -57,13 +58,13 @@ public final class DnsType implements Comparable<DnsType> {
      * use is for implementing reverse DNS lookups, but other uses include such
      * things as DNS-SD.
      */
-    public static final DnsType PTR = new DnsType(0x000c, "PTR");
+    public static final DnsRecordType PTR = new DnsRecordType(0x000c, "PTR");
 
     /**
      * Mail exchange record RFC 1035 Maps a domain name to a list of message
      * transfer agents for that domain.
      */
-    public static final DnsType MX = new DnsType(0x000f, "MX");
+    public static final DnsRecordType MX = new DnsRecordType(0x000f, "MX");
 
     /**
      * Text record RFC 1035 Originally for arbitrary human-readable text in a
@@ -72,14 +73,14 @@ public final class DnsType implements Comparable<DnsType> {
      * opportunistic encryption, Sender Policy Framework, DKIM, DMARC DNS-SD,
      * etc.
      */
-    public static final DnsType TXT = new DnsType(0x0010, "TXT");
+    public static final DnsRecordType TXT = new DnsRecordType(0x0010, "TXT");
 
     /**
      * Responsible person record RFC 1183 Information about the responsible
      * person(s) for the domain. Usually an email address with the @ replaced by
      * a .
      */
-    public static final DnsType RP = new DnsType(0x0011, "RP");
+    public static final DnsRecordType RP = new DnsRecordType(0x0011, "RP");
 
     /**
      * AFS database record RFC 1183 Location of database servers of an AFS cell.
@@ -87,14 +88,14 @@ public final class DnsType implements Comparable<DnsType> {
      * their local domain. A subtype of this record is used by the obsolete
      * DCE/DFS file system.
      */
-    public static final DnsType AFSDB = new DnsType(0x0012, "AFSDB");
+    public static final DnsRecordType AFSDB = new DnsRecordType(0x0012, "AFSDB");
 
     /**
      * Signature record RFC 2535 Signature record used in SIG(0) (RFC 2931) and
      * TKEY (RFC 2930). RFC 3755 designated RRSIG as the replacement for SIG for
      * use within DNSSEC.
      */
-    public static final DnsType SIG = new DnsType(0x0018, "SIG");
+    public static final DnsRecordType SIG = new DnsRecordType(0x0018, "SIG");
 
     /**
      * key record RFC 2535 and RFC 2930 Used only for SIG(0) (RFC 2931) and TKEY
@@ -103,32 +104,32 @@ public final class DnsType implements Comparable<DnsType> {
      * replacement within DNSSEC. RFC 4025 designates IPSECKEY as the
      * replacement for use with IPsec.
      */
-    public static final DnsType KEY = new DnsType(0x0019, "KEY");
+    public static final DnsRecordType KEY = new DnsRecordType(0x0019, "KEY");
 
     /**
      * IPv6 address record RFC 3596 Returns a 128-bit IPv6 address, most
      * commonly used to map hostnames to an IP address of the host.
      */
-    public static final DnsType AAAA = new DnsType(0x001c, "AAAA");
+    public static final DnsRecordType AAAA = new DnsRecordType(0x001c, "AAAA");
 
     /**
      * Location record RFC 1876 Specifies a geographical location associated
      * with a domain name.
      */
-    public static final DnsType LOC = new DnsType(0x001d, "LOC");
+    public static final DnsRecordType LOC = new DnsRecordType(0x001d, "LOC");
 
     /**
      * Service locator RFC 2782 Generalized service location record, used for
      * newer protocols instead of creating protocol-specific records such as MX.
      */
-    public static final DnsType SRV = new DnsType(0x0021, "SRV");
+    public static final DnsRecordType SRV = new DnsRecordType(0x0021, "SRV");
 
     /**
      * Naming Authority Pointer record RFC 3403 Allows regular expression based
      * rewriting of domain names which can then be used as URIs, further domain
      * names to lookups, etc.
      */
-    public static final DnsType NAPTR = new DnsType(0x0023, "NAPTR");
+    public static final DnsRecordType NAPTR = new DnsRecordType(0x0023, "NAPTR");
 
     /**
      * Key eXchanger record RFC 2230 Used with some cryptographic systems (not
@@ -137,12 +138,12 @@ public final class DnsType implements Comparable<DnsType> {
      * Informational status, rather than being on the IETF standards-track. It
      * has always had limited deployment, but is still in use.
      */
-    public static final DnsType KX = new DnsType(0x0024, "KX");
+    public static final DnsRecordType KX = new DnsRecordType(0x0024, "KX");
 
     /**
      * Certificate record RFC 4398 Stores PKIX, SPKI, PGP, etc.
      */
-    public static final DnsType CERT = new DnsType(0x0025, "CERT");
+    public static final DnsRecordType CERT = new DnsRecordType(0x0025, "CERT");
 
     /**
      * Delegation name record RFC 2672 DNAME creates an alias for a name and all
@@ -150,25 +151,25 @@ public final class DnsType implements Comparable<DnsType> {
      * label. Like the CNAME record, the DNS lookup will continue by retrying
      * the lookup with the new name.
      */
-    public static final DnsType DNAME = new DnsType(0x0027, "DNAME");
+    public static final DnsRecordType DNAME = new DnsRecordType(0x0027, "DNAME");
 
     /**
      * Option record RFC 2671 This is a pseudo DNS record type needed to support
      * EDNS.
      */
-    public static final DnsType OPT = new DnsType(0x0029, "OPT");
+    public static final DnsRecordType OPT = new DnsRecordType(0x0029, "OPT");
 
     /**
      * Address Prefix List record RFC 3123 Specify lists of address ranges, e.g.
      * in CIDR format, for various address families. Experimental.
      */
-    public static final DnsType APL = new DnsType(0x002a, "APL");
+    public static final DnsRecordType APL = new DnsRecordType(0x002a, "APL");
 
     /**
      * Delegation signer record RFC 4034 The record used to identify the DNSSEC
      * signing key of a delegated zone.
      */
-    public static final DnsType DS = new DnsType(0x002b, "DS");
+    public static final DnsRecordType DS = new DnsRecordType(0x002b, "DS");
 
     /**
      * SSH Public Key Fingerprint record RFC 4255 Resource record for publishing
@@ -176,47 +177,47 @@ public final class DnsType implements Comparable<DnsType> {
      * verifying the authenticity of the host. RFC 6594 defines ECC SSH keys and
      * SHA-256 hashes. See the IANA SSHFP RR parameters registry for details.
      */
-    public static final DnsType SSHFP = new DnsType(0x002c, "SSHFP");
+    public static final DnsRecordType SSHFP = new DnsRecordType(0x002c, "SSHFP");
 
     /**
      * IPsec Key record RFC 4025 Key record that can be used with IPsec.
      */
-    public static final DnsType IPSECKEY = new DnsType(0x002d, "IPSECKEY");
+    public static final DnsRecordType IPSECKEY = new DnsRecordType(0x002d, "IPSECKEY");
 
     /**
      * DNSSEC signature record RFC 4034 Signature for a DNSSEC-secured record
      * set. Uses the same format as the SIG record.
      */
-    public static final DnsType RRSIG = new DnsType(0x002e, "RRSIG");
+    public static final DnsRecordType RRSIG = new DnsRecordType(0x002e, "RRSIG");
 
     /**
      * Next-Secure record RFC 4034 Part of DNSSEC, used to prove a name does not
      * exist. Uses the same format as the (obsolete) NXT record.
      */
-    public static final DnsType NSEC = new DnsType(0x002f, "NSEC");
+    public static final DnsRecordType NSEC = new DnsRecordType(0x002f, "NSEC");
 
     /**
      * DNS Key record RFC 4034 The key record used in DNSSEC. Uses the same
      * format as the KEY record.
      */
-    public static final DnsType DNSKEY = new DnsType(0x0030, "DNSKEY");
+    public static final DnsRecordType DNSKEY = new DnsRecordType(0x0030, "DNSKEY");
 
     /**
      * DHCP identifier record RFC 4701 Used in conjunction with the FQDN option
      * to DHCP.
      */
-    public static final DnsType DHCID = new DnsType(0x0031, "DHCID");
+    public static final DnsRecordType DHCID = new DnsRecordType(0x0031, "DHCID");
 
     /**
      * NSEC record version 3 RFC 5155 An extension to DNSSEC that allows proof
      * of nonexistence for a name without permitting zonewalking.
      */
-    public static final DnsType NSEC3 = new DnsType(0x0032, "NSEC3");
+    public static final DnsRecordType NSEC3 = new DnsRecordType(0x0032, "NSEC3");
 
     /**
      * NSEC3 parameters record RFC 5155 Parameter record for use with NSEC3.
      */
-    public static final DnsType NSEC3PARAM = new DnsType(0x0033, "NSEC3PARAM");
+    public static final DnsRecordType NSEC3PARAM = new DnsRecordType(0x0033, "NSEC3PARAM");
 
     /**
      * TLSA certificate association record RFC 6698 A record for DNS-based
@@ -225,34 +226,34 @@ public final class DnsType implements Comparable<DnsType> {
      * key with the domain name where the record is found, thus forming a 'TLSA
      * certificate association'.
      */
-    public static final DnsType TLSA = new DnsType(0x0034, "TLSA");
+    public static final DnsRecordType TLSA = new DnsRecordType(0x0034, "TLSA");
 
     /**
      * Host Identity Protocol record RFC 5205 Method of separating the end-point
      * identifier and locator roles of IP addresses.
      */
-    public static final DnsType HIP = new DnsType(0x0037, "HIP");
+    public static final DnsRecordType HIP = new DnsRecordType(0x0037, "HIP");
 
     /**
      * Sender Policy Framework record RFC 4408 Specified as part of the SPF
      * protocol as an alternative to of storing SPF data in TXT records. Uses
      * the same format as the earlier TXT record.
      */
-    public static final DnsType SPF = new DnsType(0x0063, "SPF");
+    public static final DnsRecordType SPF = new DnsRecordType(0x0063, "SPF");
 
     /**
      * Secret key record RFC 2930 A method of providing keying material to be
      * used with TSIG that is encrypted under the public key in an accompanying
      * KEY RR..
      */
-    public static final DnsType TKEY = new DnsType(0x00f9, "TKEY");
+    public static final DnsRecordType TKEY = new DnsRecordType(0x00f9, "TKEY");
 
     /**
      * Transaction Signature record RFC 2845 Can be used to authenticate dynamic
      * updates as coming from an approved client, or to authenticate responses
      * as coming from an approved recursive name server similar to DNSSEC.
      */
-    public static final DnsType TSIG = new DnsType(0x00fa, "TSIG");
+    public static final DnsRecordType TSIG = new DnsRecordType(0x00fa, "TSIG");
 
     /**
      * Incremental Zone Transfer record RFC 1996 Requests a zone transfer of the
@@ -261,13 +262,13 @@ public final class DnsType implements Comparable<DnsType> {
      * authoritative server is unable to fulfill the request due to
      * configuration or lack of required deltas.
      */
-    public static final DnsType IXFR = new DnsType(0x00fb, "IXFR");
+    public static final DnsRecordType IXFR = new DnsRecordType(0x00fb, "IXFR");
 
     /**
      * Authoritative Zone Transfer record RFC 1035 Transfer entire zone file
      * from the master name server to secondary name servers.
      */
-    public static final DnsType AXFR = new DnsType(0x00fc, "AXFR");
+    public static final DnsRecordType AXFR = new DnsRecordType(0x00fc, "AXFR");
 
     /**
      * All cached records RFC 1035 Returns all records of all types known to the
@@ -278,49 +279,50 @@ public final class DnsType implements Comparable<DnsType> {
      * returned. Sometimes referred to as ANY, for example in Windows nslookup
      * and Wireshark.
      */
-    public static final DnsType ANY = new DnsType(0x00ff, "ANY");
+    public static final DnsRecordType ANY = new DnsRecordType(0x00ff, "ANY");
 
     /**
      * Certification Authority Authorization record RFC 6844 CA pinning,
      * constraining acceptable CAs for a host/domain.
      */
-    public static final DnsType CAA = new DnsType(0x0101, "CAA");
+    public static final DnsRecordType CAA = new DnsRecordType(0x0101, "CAA");
 
     /**
      * DNSSEC Trust Authorities record N/A Part of a deployment proposal for
      * DNSSEC without a signed DNS root. See the IANA database and Weiler Spec
      * for details. Uses the same format as the DS record.
      */
-    public static final DnsType TA = new DnsType(0x8000, "TA");
+    public static final DnsRecordType TA = new DnsRecordType(0x8000, "TA");
 
     /**
      * DNSSEC Lookaside Validation record RFC 4431 For publishing DNSSEC trust
      * anchors outside of the DNS delegation chain. Uses the same format as the
      * DS record. RFC 5074 describes a way of using these records.
      */
-    public static final DnsType DLV = new DnsType(0x8001, "DLV");
+    public static final DnsRecordType DLV = new DnsRecordType(0x8001, "DLV");
 
-    private static final Map<String, DnsType> BY_NAME = new HashMap<String, DnsType>();
+    private static final Map<String, DnsRecordType> BY_NAME = new HashMap<String, DnsRecordType>();
-    private static final IntObjectHashMap<DnsType> BY_TYPE = new IntObjectHashMap<DnsType>();
+    private static final IntObjectHashMap<DnsRecordType> BY_TYPE = new IntObjectHashMap<DnsRecordType>();
     private static final String EXPECTED;
 
     static {
-        DnsType[] all = {
+        DnsRecordType[] all = {
                 A, NS, CNAME, SOA, PTR, MX, TXT, RP, AFSDB, SIG, KEY, AAAA, LOC, SRV, NAPTR, KX, CERT, DNAME, OPT, APL,
                 DS, SSHFP, IPSECKEY, RRSIG, NSEC, DNSKEY, DHCID, NSEC3, NSEC3PARAM, TLSA, HIP, SPF, TKEY, TSIG, IXFR,
                 AXFR, ANY, CAA, TA, DLV
         };
 
-        StringBuilder expected = new StringBuilder(512);
+        final StringBuilder expected = new StringBuilder(512);
-        expected.append(" (expected: ");
 
-        for (DnsType type: all) {
+        expected.append(" (expected: ");
+        for (DnsRecordType type: all) {
             BY_NAME.put(type.name(), type);
             BY_TYPE.put(type.intValue(), type);
-            expected.append(type.name());
+
-            expected.append('(');
+            expected.append(type.name())
-            expected.append(type.intValue());
+                    .append('(')
-            expected.append("), ");
+                    .append(type.intValue())
+                    .append("), ");
         }
 
         expected.setLength(expected.length() - 2);
@@ -328,33 +330,31 @@ public final class DnsType implements Comparable<DnsType> {
         EXPECTED = expected.toString();
     }
 
-    public static DnsType valueOf(int intValue) {
+    public static DnsRecordType valueOf(int intValue) {
-        DnsType result = BY_TYPE.get(intValue);
+        DnsRecordType result = BY_TYPE.get(intValue);
         if (result == null) {
-            return new DnsType(intValue, "UNKNOWN");
+            return new DnsRecordType(intValue);
         }
         return result;
     }
 
-    public static DnsType valueOf(String name) {
+    public static DnsRecordType valueOf(String name) {
-        DnsType result = BY_NAME.get(name);
+        DnsRecordType result = BY_NAME.get(name);
         if (result == null) {
             throw new IllegalArgumentException("name: " + name + EXPECTED);
         }
         return result;
     }
 
-    /**
-     * Returns a new instance.
-     */
-    public static DnsType valueOf(int intValue, String name) {
-        return new DnsType(intValue, name);
-    }
-
     private final int intValue;
     private final String name;
+    private String text;
 
-    private DnsType(int intValue, String name) {
+    private DnsRecordType(int intValue) {
+        this(intValue, "UNKNOWN");
+    }
+
+    public DnsRecordType(int intValue, String name) {
         if ((intValue & 0xffff) != intValue) {
             throw new IllegalArgumentException("intValue: " + intValue + " (expected: 0 ~ 65535)");
         }
@@ -383,16 +383,20 @@ public final class DnsType implements Comparable<DnsType> {
 
     @Override
     public boolean equals(Object o) {
-        return o instanceof DnsType && ((DnsType) o).intValue == intValue;
+        return o instanceof DnsRecordType && ((DnsRecordType) o).intValue == intValue;
     }
 
     @Override
-    public int compareTo(DnsType o) {
+    public int compareTo(DnsRecordType o) {
         return intValue() - o.intValue();
     }
 
     @Override
     public String toString() {
-        return name;
+        String text = this.text;
+        if (text == null) {
+            this.text = text = name + '(' + intValue() + ')';
+        }
+        return text;
     }
 }

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsResource.java

@@ -1,119 +0,0 @@
-/*
- * Copyright 2013 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.handler.codec.dns;
-
-import io.netty.buffer.ByteBuf;
-import io.netty.buffer.ByteBufHolder;
-
-/**
- * Represents any resource record (answer, authority, or additional resource
- * records).
- */
-public final class DnsResource extends DnsEntry implements ByteBufHolder {
-
-    private final long ttl;
-    private final ByteBuf content;
-
-    /**
-     * Constructs a resource record.
-     *
-     * @param name
-     *            the domain name
-     * @param type
-     *            the type of record being returned
-     * @param aClass
-     *            the class for this resource record
-     * @param ttl
-     *            the time to live after reading
-     * @param content
-     *            the data contained in this record
-     */
-    public DnsResource(String name, DnsType type, DnsClass aClass, long ttl, ByteBuf content) {
-        super(name, type, aClass);
-        this.ttl = ttl;
-        this.content = content;
-    }
-
-    /**
-     * Returns the time to live after reading for this resource record.
-     */
-    public long timeToLive() {
-        return ttl;
-    }
-
-    /**
-     * Returns the data contained in this resource record.
-     */
-    @Override
-    public ByteBuf content() {
-        return content;
-    }
-
-    /**
-     * Returns a deep copy of this resource record.
-     */
-    @Override
-    public DnsResource copy() {
-        return new DnsResource(name(), type(), dnsClass(), ttl, content.copy());
-    }
-
-    /**
-     * Returns a duplicate of this resource record.
-     */
-    @Override
-    public DnsResource duplicate() {
-        return new DnsResource(name(), type(), dnsClass(), ttl, content.duplicate());
-    }
-
-    @Override
-    public int refCnt() {
-        return content.refCnt();
-    }
-
-    @Override
-    public DnsResource retain() {
-        content.retain();
-        return this;
-    }
-
-    @Override
-    public DnsResource retain(int increment) {
-        content.retain(increment);
-        return this;
-    }
-
-    @Override
-    public boolean release() {
-        return content.release();
-    }
-
-    @Override
-    public boolean release(int decrement) {
-        return content.release(decrement);
-    }
-
-    @Override
-    public DnsResource touch() {
-        content.touch();
-        return this;
-    }
-
-    @Override
-    public DnsResource touch(Object hint) {
-        content.touch(hint);
-        return this;
-    }
-}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsResponse.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 The Netty Project
+ * Copyright 2015 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -15,86 +15,99 @@
  */
 package io.netty.handler.codec.dns;
 
-import java.net.InetSocketAddress;
-
 /**
- * A DNS response packet which is sent to a client after a server receives a
+ * A DNS response message.
- * query.
  */
-public final class DnsResponse extends DnsMessage {
+public interface DnsResponse extends DnsMessage {
-
-    private final InetSocketAddress sender;
-
-    public DnsResponse(int id, InetSocketAddress sender) {
-        super(id);
-        if (sender == null) {
-            throw new NullPointerException("sender");
-        }
-        this.sender = sender;
-    }
 
     /**
-     * The {@link InetSocketAddress} of the sender of this {@link DnsResponse}
+     * Returns {@code true} if responding server is authoritative for the domain
+     * name in the query message.
      */
-    public InetSocketAddress sender() {
+    boolean isAuthoritativeAnswer();
-        return sender;
+
-    }
+    /**
+     * Set to {@code true} if responding server is authoritative for the domain
+     * name in the query message.
+     *
+     * @param authoritativeAnswer flag for authoritative answer
+     */
+    DnsResponse setAuthoritativeAnswer(boolean authoritativeAnswer);
+
+    /**
+     * Returns {@code true} if response has been truncated, usually if it is
+     * over 512 bytes.
+     */
+    boolean isTruncated();
+
+    /**
+     * Set to {@code true} if response has been truncated (usually happens for
+     * responses over 512 bytes).
+     *
+     * @param truncated flag for truncation
+     */
+    DnsResponse setTruncated(boolean truncated);
+
+    /**
+     * Returns {@code true} if DNS server can handle recursive queries.
+     */
+    boolean isRecursionAvailable();
+
+    /**
+     * Set to {@code true} if DNS server can handle recursive queries.
+     *
+     * @param recursionAvailable flag for recursion availability
+     */
+    DnsResponse setRecursionAvailable(boolean recursionAvailable);
+
+    /**
+     * Returns the 4 bit return code.
+     */
+    DnsResponseCode code();
+
+    /**
+     * Sets the response code for this message.
+     *
+     * @param code the response code
+     */
+    DnsResponse setCode(DnsResponseCode code);
 
     @Override
-    public DnsResponse addAnswer(DnsResource answer) {
+    DnsResponse setId(int id);
-        super.addAnswer(answer);
-        return this;
-    }
 
     @Override
-    public DnsResponse addQuestion(DnsQuestion question) {
+    DnsResponse setOpCode(DnsOpCode opCode);
-        super.addQuestion(question);
-        return this;
-    }
 
     @Override
-    public DnsResponse addAuthorityResource(DnsResource resource) {
+    DnsResponse setRecursionDesired(boolean recursionDesired);
-        super.addAuthorityResource(resource);
-        return this;
-    }
 
     @Override
-    public DnsResponse addAdditionalResource(DnsResource resource) {
+    DnsResponse setZ(int z);
-        super.addAdditionalResource(resource);
-        return this;
-    }
 
     @Override
-    public DnsResponse touch(Object hint) {
+    DnsResponse setRecord(DnsSection section, DnsRecord record);
-        super.touch(hint);
-        return this;
-    }
 
     @Override
-    public DnsResponse retain() {
+    DnsResponse addRecord(DnsSection section, DnsRecord record);
-        super.retain();
-        return this;
-    }
 
     @Override
-    public DnsResponse retain(int increment) {
+    DnsResponse addRecord(DnsSection section, int index, DnsRecord record);
-        super.retain(increment);
-        return this;
-    }
 
     @Override
-    public DnsResponse touch() {
+    DnsResponse clear(DnsSection section);
-        super.touch();
-        return this;
-    }
 
     @Override
-    public DnsResponseHeader header() {
+    DnsResponse clear();
-        return (DnsResponseHeader) super.header();
-    }
 
     @Override
-    protected DnsResponseHeader newHeader(int id) {
+    DnsResponse touch();
-        return new DnsResponseHeader(this, id);
+
-    }
+    @Override
+    DnsResponse touch(Object hint);
+
+    @Override
+    DnsResponse retain();
+
+    @Override
+    DnsResponse retain(int increment);
 }

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsResponseCode.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013 The Netty Project
+ * Copyright 2015 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -15,159 +15,183 @@
  */
 package io.netty.handler.codec.dns;
 
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
+
 /**
- * Represents the possible response codes a server may send after receiving a
+ * The DNS {@code RCODE}, as defined in <a href="https://tools.ietf.org/html/rfc2929">RFC2929</a>.
- * query. A response code of 0 indicates no error.
  */
-public final class DnsResponseCode implements Comparable<DnsResponseCode> {
+public class DnsResponseCode implements Comparable<DnsResponseCode> {
 
     /**
-     * ID 0, no error
+     * The 'NoError' DNS RCODE (0), as defined in <a href="https://tools.ietf.org/html/rfc1035">RFC1035</a>.
      */
-    public static final DnsResponseCode NOERROR = new DnsResponseCode(0, "no error");
+    public static final DnsResponseCode NOERROR = new DnsResponseCode(0, "NoError");
 
     /**
-     * ID 1, format error
+     * The 'FormErr' DNS RCODE (1), as defined in <a href="https://tools.ietf.org/html/rfc1035">RFC1035</a>.
      */
-    public static final DnsResponseCode FORMERROR = new DnsResponseCode(1, "format error");
+    public static final DnsResponseCode FORMERR = new DnsResponseCode(1, "FormErr");
 
     /**
-     * ID 2, server failure
+     * The 'ServFail' DNS RCODE (2), as defined in <a href="https://tools.ietf.org/html/rfc1035">RFC1035</a>.
      */
-    public static final DnsResponseCode SERVFAIL = new DnsResponseCode(2, "server failure");
+    public static final DnsResponseCode SERVFAIL = new DnsResponseCode(2, "ServFail");
 
     /**
-     * ID 3, name error
+     * The 'NXDomain' DNS RCODE (3), as defined in <a href="https://tools.ietf.org/html/rfc1035">RFC1035</a>.
      */
-    public static final DnsResponseCode NXDOMAIN = new DnsResponseCode(3, "name error");
+    public static final DnsResponseCode NXDOMAIN = new DnsResponseCode(3, "NXDomain");
 
     /**
-     * ID 4, not implemented
+     * The 'NotImp' DNS RCODE (4), as defined in <a href="https://tools.ietf.org/html/rfc1035">RFC1035</a>.
      */
-    public static final DnsResponseCode NOTIMPL = new DnsResponseCode(4, "not implemented");
+    public static final DnsResponseCode NOTIMP = new DnsResponseCode(4, "NotImp");
 
     /**
-     * ID 5, operation refused
+     * The 'Refused' DNS RCODE (5), as defined in <a href="https://tools.ietf.org/html/rfc1035">RFC1035</a>.
      */
-    public static final DnsResponseCode REFUSED = new DnsResponseCode(5, "operation refused");
+    public static final DnsResponseCode REFUSED = new DnsResponseCode(5, "Refused");
 
     /**
-     * ID 6, domain name should not exist
+     * The 'YXDomain' DNS RCODE (6), as defined in <a href="https://tools.ietf.org/html/rfc2136">RFC2136</a>.
      */
-    public static final DnsResponseCode YXDOMAIN = new DnsResponseCode(6, "domain name should not exist");
+    public static final DnsResponseCode YXDOMAIN = new DnsResponseCode(6, "YXDomain");
 
     /**
-     * ID 7, resource record set should not exist
+     * The 'YXRRSet' DNS RCODE (7), as defined in <a href="https://tools.ietf.org/html/rfc2136">RFC2136</a>.
      */
-    public static final DnsResponseCode YXRRSET = new DnsResponseCode(7, "resource record set should not exist");
+    public static final DnsResponseCode YXRRSET = new DnsResponseCode(7, "YXRRSet");
 
     /**
-     * ID 8, rrset does not exist
+     * The 'NXRRSet' DNS RCODE (8), as defined in <a href="https://tools.ietf.org/html/rfc2136">RFC2136</a>.
      */
-    public static final DnsResponseCode NXRRSET = new DnsResponseCode(8, "rrset does not exist");
+    public static final DnsResponseCode NXRRSET = new DnsResponseCode(8, "NXRRSet");
 
     /**
-     * ID 9, not authoritative for zone
+     * The 'NotAuth' DNS RCODE (9), as defined in <a href="https://tools.ietf.org/html/rfc2136">RFC2136</a>.
      */
-    public static final DnsResponseCode NOTAUTH = new DnsResponseCode(9, "not authoritative for zone");
+    public static final DnsResponseCode NOTAUTH = new DnsResponseCode(9, "NotAuth");
 
     /**
-     * ID 10, name not in zone
+     * The 'NotZone' DNS RCODE (10), as defined in <a href="https://tools.ietf.org/html/rfc2136">RFC2136</a>.
      */
-    public static final DnsResponseCode NOTZONE = new DnsResponseCode(10, "name not in zone");
+    public static final DnsResponseCode NOTZONE = new DnsResponseCode(10, "NotZone");
 
     /**
-     * ID 11, bad extension mechanism for version
+     * The 'BADVERS' or 'BADSIG' DNS RCODE (16), as defined in <a href="https://tools.ietf.org/html/rfc2671">RFC2671</a>
+     * and <a href="https://tools.ietf.org/html/rfc2845">RFC2845</a>.
      */
-    public static final DnsResponseCode BADVERS = new DnsResponseCode(11, "bad extension mechanism for version");
+    public static final DnsResponseCode BADVERS_OR_BADSIG = new DnsResponseCode(16, "BADVERS_OR_BADSIG");
 
     /**
-     * ID 12, bad signature
+     * The 'BADKEY' DNS RCODE (17), as defined in <a href="https://tools.ietf.org/html/rfc2845">RFC2845</a>.
      */
-    public static final DnsResponseCode BADSIG = new DnsResponseCode(12, "bad signature");
+    public static final DnsResponseCode BADKEY = new DnsResponseCode(17, "BADKEY");
 
     /**
-     * ID 13, bad key
+     * The 'BADTIME' DNS RCODE (18), as defined in <a href="https://tools.ietf.org/html/rfc2845">RFC2845</a>.
      */
-    public static final DnsResponseCode BADKEY = new DnsResponseCode(13, "bad key");
+    public static final DnsResponseCode BADTIME = new DnsResponseCode(18, "BADTIME");
 
     /**
-     * ID 14, bad timestamp
+     * The 'BADMODE' DNS RCODE (19), as defined in <a href="https://tools.ietf.org/html/rfc2930">RFC2930</a>.
      */
-    public static final DnsResponseCode BADTIME = new DnsResponseCode(14, "bad timestamp");
+    public static final DnsResponseCode BADMODE = new DnsResponseCode(19, "BADMODE");
-
-    private final int errorCode;
-    private final String message;
 
     /**
-     * Returns the {@link DnsResponseCode} that corresponds with the given
+     * The 'BADNAME' DNS RCODE (20), as defined in <a href="https://tools.ietf.org/html/rfc2930">RFC2930</a>.
-     * {@code responseCode}.
+     */
+    public static final DnsResponseCode BADNAME = new DnsResponseCode(20, "BADNAME");
+
+    /**
+     * The 'BADALG' DNS RCODE (21), as defined in <a href="https://tools.ietf.org/html/rfc2930">RFC2930</a>.
+     */
+    public static final DnsResponseCode BADALG = new DnsResponseCode(21, "BADALG");
+
+    /**
+     * Returns the {@link DnsResponseCode} that corresponds with the given {@code responseCode}.
      *
-     * @param responseCode
+     * @param responseCode the DNS RCODE
-     *            the error code's id
+     *
-     * @return corresponding {@link DnsResponseCode} or {@code null} if none can be found.
+     * @return the corresponding {@link DnsResponseCode}
      */
     public static DnsResponseCode valueOf(int responseCode) {
         switch (responseCode) {
-            case 0:
+        case 0:
-                return NOERROR;
+            return NOERROR;
-            case 1:
+        case 1:
-                return FORMERROR;
+            return FORMERR;
-            case 2:
+        case 2:
-                return SERVFAIL;
+            return SERVFAIL;
-            case 3:
+        case 3:
-                return NXDOMAIN;
+            return NXDOMAIN;
-            case 4:
+        case 4:
-                return NOTIMPL;
+            return NOTIMP;
-            case 5:
+        case 5:
-                return REFUSED;
+            return REFUSED;
-            case 6:
+        case 6:
-                return YXDOMAIN;
+            return YXDOMAIN;
-            case 7:
+        case 7:
-                return YXRRSET;
+            return YXRRSET;
-            case 8:
+        case 8:
-                return NXRRSET;
+            return NXRRSET;
-            case 9:
+        case 9:
-                return NOTAUTH;
+            return NOTAUTH;
-            case 10:
+        case 10:
-                return NOTZONE;
+            return NOTZONE;
-            case 11:
+        case 16:
-                return BADVERS;
+            return BADVERS_OR_BADSIG;
-            case 12:
+        case 17:
-                return BADSIG;
+            return BADKEY;
-            case 13:
+        case 18:
-                return BADKEY;
+            return BADTIME;
-            case 14:
+        case 19:
-                return BADTIME;
+            return BADMODE;
-            default:
+        case 20:
-                return new DnsResponseCode(responseCode, null);
+            return BADNAME;
+        case 21:
+            return BADALG;
+        default:
+            return new DnsResponseCode(responseCode);
         }
     }
 
-    public DnsResponseCode(int errorCode, String message) {
+    private final int code;
-        this.errorCode = errorCode;
+    private final String name;
-        this.message = message;
+    private String text;
+
+    private DnsResponseCode(int code) {
+        this(code, "UNKNOWN");
+    }
+
+    public DnsResponseCode(int code, String name) {
+        if (code < 0 || code > 65535) {
+            throw new IllegalArgumentException("code: " + code + " (expected: 0 ~ 65535)");
+        }
+
+        this.code = code;
+        this.name = checkNotNull(name, "name");
     }
 
     /**
      * Returns the error code for this {@link DnsResponseCode}.
      */
-    public int code() {
+    public int intValue() {
-        return errorCode;
+        return code;
     }
 
     @Override
     public int compareTo(DnsResponseCode o) {
-        return code() - o.code();
+        return intValue() - o.intValue();
     }
 
     @Override
     public int hashCode() {
-        return code();
+        return intValue();
     }
 
     /**
-     * Equality of {@link DnsResponseCode} only depends on {@link #code()}.
+     * Equality of {@link DnsResponseCode} only depends on {@link #intValue()}.
      */
     @Override
     public boolean equals(Object o) {
@@ -175,7 +199,7 @@ public final class DnsResponseCode implements Comparable<DnsResponseCode> {
             return false;
         }
 
-        return code() == ((DnsResponseCode) o).code();
+        return intValue() == ((DnsResponseCode) o).intValue();
     }
 
     /**
@@ -183,9 +207,10 @@ public final class DnsResponseCode implements Comparable<DnsResponseCode> {
      */
     @Override
     public String toString() {
-        if (message == null) {
+        String text = this.text;
-            return "DnsResponseCode(" + errorCode + ')';
+        if (text == null) {
+            this.text = text = name + '(' + intValue() + ')';
         }
-        return "DnsResponseCode(" + errorCode + ", " + message + ')';
+        return text;
     }
 }

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsResponseDecoder.java

@@ -1,172 +0,0 @@
-/*
- * Copyright 2013 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.handler.codec.dns;
-
-import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelHandler;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.socket.DatagramPacket;
-import io.netty.handler.codec.CorruptedFrameException;
-import io.netty.handler.codec.MessageToMessageDecoder;
-import io.netty.util.CharsetUtil;
-
-import java.util.List;
-
-/**
- * DnsResponseDecoder accepts {@link io.netty.channel.socket.DatagramPacket} and encodes to
- * {@link DnsResponse}. This class also contains methods for decoding parts of
- * DnsResponses such as questions and resource records.
- */
-@ChannelHandler.Sharable
-public class DnsResponseDecoder extends MessageToMessageDecoder<DatagramPacket> {
-
-    @Override
-    protected void decode(ChannelHandlerContext ctx, DatagramPacket packet, List<Object> out) throws Exception {
-        ByteBuf buf = packet.content();
-
-        int id = buf.readUnsignedShort();
-
-        DnsResponse response = new DnsResponse(id, packet.sender());
-        DnsResponseHeader header = response.header();
-        int flags = buf.readUnsignedShort();
-        header.setType(flags >> 15);
-        header.setOpcode(flags >> 11 & 0xf);
-        header.setRecursionDesired((flags >> 8 & 1) == 1);
-        header.setAuthoritativeAnswer((flags >> 10 & 1) == 1);
-        header.setTruncated((flags >> 9 & 1) == 1);
-        header.setRecursionAvailable((flags >> 7 & 1) == 1);
-        header.setZ(flags >> 4 & 0x7);
-        header.setResponseCode(DnsResponseCode.valueOf(flags & 0xf));
-
-        int questions = buf.readUnsignedShort();
-        int answers = buf.readUnsignedShort();
-        int authorities = buf.readUnsignedShort();
-        int additionals = buf.readUnsignedShort();
-
-        for (int i = 0; i < questions; i++) {
-            response.addQuestion(decodeQuestion(buf));
-        }
-        if (header.responseCode() != DnsResponseCode.NOERROR) {
-            // response code for error
-            out.add(response);
-            return;
-        }
-        boolean release = true;
-        try {
-            for (int i = 0; i < answers; i++) {
-                response.addAnswer(decodeResource(buf));
-            }
-            for (int i = 0; i < authorities; i++) {
-                response.addAuthorityResource(decodeResource(buf));
-            }
-            for (int i = 0; i < additionals; i++) {
-                response.addAdditionalResource(decodeResource(buf));
-            }
-            out.add(response);
-            release = false;
-        } finally {
-            if (release) {
-                // We need to release te DnsResources in case of an Exception as we called retain() on the buffer.
-                releaseDnsResources(response.answers());
-                releaseDnsResources(response.authorityResources());
-                releaseDnsResources(response.additionalResources());
-            }
-        }
-    }
-
-    private static void releaseDnsResources(List<DnsResource> resources) {
-        int size = resources.size();
-        for (int i = 0; i < size; i++) {
-            DnsResource resource = resources.get(i);
-            resource.release();
-        }
-    }
-
-    /**
-     * Retrieves a domain name given a buffer containing a DNS packet. If the
-     * name contains a pointer, the position of the buffer will be set to
-     * directly after the pointer's index after the name has been read.
-     *
-     * @param buf
-     *            the byte buffer containing the DNS packet
-     * @return the domain name for an entry
-     */
-    private static String readName(ByteBuf buf) {
-        int position = -1;
-        int checked = 0;
-        int length = buf.writerIndex();
-        StringBuilder name = new StringBuilder();
-        for (int len = buf.readUnsignedByte(); buf.isReadable() && len != 0; len = buf.readUnsignedByte()) {
-            boolean pointer = (len & 0xc0) == 0xc0;
-            if (pointer) {
-                if (position == -1) {
-                    position = buf.readerIndex() + 1;
-                }
-                buf.readerIndex((len & 0x3f) << 8 | buf.readUnsignedByte());
-                // check for loops
-                checked += 2;
-                if (checked >= length) {
-                    throw new CorruptedFrameException("name contains a loop.");
-                }
-            } else {
-                name.append(buf.toString(buf.readerIndex(), len, CharsetUtil.UTF_8)).append('.');
-                buf.skipBytes(len);
-            }
-        }
-        if (position != -1) {
-            buf.readerIndex(position);
-        }
-        if (name.length() == 0) {
-            return "";
-        }
-
-        return name.substring(0, name.length() - 1);
-    }
-
-    /**
-     * Decodes a question, given a DNS packet in a byte buffer.
-     *
-     * @param buf
-     *            the byte buffer containing the DNS packet
-     * @return a decoded {@link DnsQuestion}
-     */
-    private static DnsQuestion decodeQuestion(ByteBuf buf) {
-        String name = readName(buf);
-        DnsType type = DnsType.valueOf(buf.readUnsignedShort());
-        DnsClass qClass = DnsClass.valueOf(buf.readUnsignedShort());
-        return new DnsQuestion(name, type, qClass);
-    }
-
-    /**
-     * Decodes a resource record, given a DNS packet in a byte buffer.
-     *
-     * @param buf
-     *            the byte buffer containing the DNS packet
-     * @return a {@link DnsResource} record containing response data
-     */
-    private static DnsResource decodeResource(ByteBuf buf) {
-        String name = readName(buf);
-        DnsType type = DnsType.valueOf(buf.readUnsignedShort());
-        DnsClass aClass = DnsClass.valueOf(buf.readUnsignedShort());
-        long ttl = buf.readUnsignedInt();
-        int len = buf.readUnsignedShort();
-
-        int readerIndex = buf.readerIndex();
-        ByteBuf payload = buf.duplicate().setIndex(readerIndex, readerIndex + len).retain();
-        buf.readerIndex(readerIndex + len);
-        return new DnsResource(name, type, aClass, ttl, payload);
-    }
-}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsResponseHeader.java

@@ -1,168 +0,0 @@
-/*
- * Copyright 2013 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.handler.codec.dns;
-
-/**
- * The DNS response header class which is used when receiving data from a DNS
- * server. Contains information contained in a DNS response header, such as
- * recursion availability, and response codes.
- */
-public final class DnsResponseHeader extends DnsHeader {
-
-    private boolean authoritativeAnswer;
-    private boolean truncated;
-    private boolean recursionAvailable;
-
-    private DnsResponseCode responseCode;
-
-    /**
-     * Constructor for a DNS packet response header. The id is received by
-     * reading a {@link DnsQuery} and is sent back to the client.
-     *
-     * @param parent
-     *            the {@link DnsMessage} this header belongs to
-     * @param id
-     *            a 2 bit unsigned identification number received from client
-     */
-    public DnsResponseHeader(DnsMessage parent, int id) {
-        super(parent);
-        setId(id);
-    }
-
-    /**
-     * Returns {@code true} if responding server is authoritative for the domain
-     * name in the query message.
-     */
-    public boolean isAuthoritativeAnswer() {
-        return authoritativeAnswer;
-    }
-
-    /**
-     * Returns {@code true} if response has been truncated, usually if it is
-     * over 512 bytes.
-     */
-    public boolean isTruncated() {
-        return truncated;
-    }
-
-    /**
-     * Returns {@code true} if DNS server can handle recursive queries.
-     */
-    public boolean isRecursionAvailable() {
-        return recursionAvailable;
-    }
-
-    /**
-     * Returns the 4 bit return code.
-     */
-    public DnsResponseCode responseCode() {
-        return responseCode;
-    }
-
-    /**
-     * Returns the {@link DnsMessage} type. This will always return
-     * {@code TYPE_RESPONSE}.
-     */
-    @Override
-    public int type() {
-        return TYPE_RESPONSE;
-    }
-
-    /**
-     * Set to {@code true} if responding server is authoritative for the domain
-     * name in the query message.
-     *
-     * @param authoritativeAnswer
-     *            flag for authoritative answer
-     */
-    public DnsResponseHeader setAuthoritativeAnswer(boolean authoritativeAnswer) {
-        this.authoritativeAnswer = authoritativeAnswer;
-        return this;
-    }
-
-    /**
-     * Set to {@code true} if response has been truncated (usually happens for
-     * responses over 512 bytes).
-     *
-     * @param truncated
-     *            flag for truncation
-     */
-    public DnsResponseHeader setTruncated(boolean truncated) {
-        this.truncated = truncated;
-        return this;
-    }
-
-    /**
-     * Set to {@code true} if DNS server can handle recursive queries.
-     *
-     * @param recursionAvailable
-     *            flag for recursion availability
-     */
-    public DnsResponseHeader setRecursionAvailable(boolean recursionAvailable) {
-        this.recursionAvailable = recursionAvailable;
-        return this;
-    }
-
-    /**
-     * Sets the response code for this message.
-     *
-     * @param responseCode
-     *            the response code
-     */
-    public DnsResponseHeader setResponseCode(DnsResponseCode responseCode) {
-        this.responseCode = responseCode;
-        return this;
-    }
-
-    /**
-     * Sets the {@link DnsHeader} type. Must be {@code TYPE_RESPONSE}.
-     *
-     * @param type
-     *            message type
-     * @return the header to allow method chaining
-     */
-    @Override
-    public DnsResponseHeader setType(int type) {
-        if (type != TYPE_RESPONSE) {
-            throw new IllegalArgumentException("type cannot be anything but TYPE_RESPONSE (1) for a response header.");
-        }
-        super.setType(type);
-        return this;
-    }
-
-    @Override
-    public DnsResponseHeader setId(int id) {
-        super.setId(id);
-        return this;
-    }
-
-    @Override
-    public DnsHeader setRecursionDesired(boolean recursionDesired) {
-        return super.setRecursionDesired(recursionDesired);
-    }
-
-    @Override
-    public DnsResponseHeader setOpcode(int opcode) {
-        super.setOpcode(opcode);
-        return this;
-    }
-
-    @Override
-    public DnsResponseHeader setZ(int z) {
-        super.setZ(z);
-        return this;
-    }
-}

codec-dns/src/main/java/io/netty/handler/codec/dns/DnsSection.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2015 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.dns;
+
+/**
+ * Represents a section of a {@link DnsMessage}.
+ */
+public enum DnsSection {
+    /**
+     * The section that contains {@link DnsQuestion}s.
+     */
+    QUESTION,
+    /**
+     * The section that contains the answer {@link DnsRecord}s.
+     */
+    ANSWER,
+    /**
+     * The section that contains the authority {@link DnsRecord}s.
+     */
+    AUTHORITY,
+    /**
+     * The section that contains the additional {@link DnsRecord}s.
+     */
+    ADDITIONAL
+}

codec-dns/src/main/java/io/netty/handler/codec/dns/package-info.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 The Netty Project
+ * Copyright 2015 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -15,7 +15,6 @@
  */
 
 /**
- * DNS codec information for writing to and reading from a DNS server.
+ * DNS codec.
- * Includes decoders and classes for representing messages and resources.
  */
 package io.netty.handler.codec.dns;

codec-dns/src/test/java/io/netty/handler/codec/dns/DnsQueryTest.java

@@ -25,29 +25,40 @@ import java.net.InetSocketAddress;
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
 public class DnsQueryTest {
 
     @Test
     public void writeQueryTest() throws Exception {
         InetSocketAddress addr = new InetSocketAddress(0);
-        EmbeddedChannel embedder = new EmbeddedChannel(new DnsQueryEncoder());
+        EmbeddedChannel embedder = new EmbeddedChannel(new DatagramDnsQueryEncoder());
         List<DnsQuery> queries = new ArrayList<DnsQuery>(5);
-        queries.add(new DnsQuery(1, addr).addQuestion(new DnsQuestion("1.0.0.127.in-addr.arpa", DnsType.PTR)));
+        queries.add(new DatagramDnsQuery(addr, null, 1).setRecord(
-        queries.add(new DnsQuery(1, addr).addQuestion(new DnsQuestion("www.example.com", DnsType.A)));
+                DnsSection.QUESTION,
-        queries.add(new DnsQuery(1, addr).addQuestion(new DnsQuestion("example.com", DnsType.AAAA)));
+                new DefaultDnsQuestion("1.0.0.127.in-addr.arpa", DnsRecordType.PTR)));
-        queries.add(new DnsQuery(1, addr).addQuestion(new DnsQuestion("example.com", DnsType.MX)));
+        queries.add(new DatagramDnsQuery(addr, null, 1).setRecord(
-        queries.add(new DnsQuery(1, addr).addQuestion(new DnsQuestion("example.com", DnsType.CNAME)));
+                DnsSection.QUESTION,
+                new DefaultDnsQuestion("www.example.com", DnsRecordType.A)));
+        queries.add(new DatagramDnsQuery(addr, null, 1).setRecord(
+                DnsSection.QUESTION,
+                new DefaultDnsQuestion("example.com", DnsRecordType.AAAA)));
+        queries.add(new DatagramDnsQuery(addr, null, 1).setRecord(
+                DnsSection.QUESTION,
+                new DefaultDnsQuestion("example.com", DnsRecordType.MX)));
+        queries.add(new DatagramDnsQuery(addr, null, 1).setRecord(
+                DnsSection.QUESTION,
+                new DefaultDnsQuestion("example.com", DnsRecordType.CNAME)));
 
         for (DnsQuery query: queries) {
-            Assert.assertEquals("Invalid question count, expected 1.", 1, query.header().questionCount());
+            assertThat(query.count(DnsSection.QUESTION), is(1));
-            Assert.assertEquals("Invalid answer count, expected 0.", 0, query.header().answerCount());
+            assertThat(query.count(DnsSection.ANSWER), is(0));
-            Assert.assertEquals("Invalid authority resource record count, expected 0.", 0, query.header()
+            assertThat(query.count(DnsSection.AUTHORITY), is(0));
-                    .authorityResourceCount());
+            assertThat(query.count(DnsSection.ADDITIONAL), is(0));
-            Assert.assertEquals("Invalid additional resource record count, expected 0.", 0, query.header()
+
-                    .additionalResourceCount());
-            Assert.assertEquals("Invalid type, should be TYPE_QUERY (0)", DnsHeader.TYPE_QUERY, query.header()
-                    .type());
             embedder.writeOutbound(query);
+
             DatagramPacket packet = embedder.readOutbound();
             Assert.assertTrue(packet.content().isReadable());
             packet.release();

codec-dns/src/test/java/io/netty/handler/codec/dns/DnsRecordTypeTest.java

@@ -25,13 +25,13 @@ import java.util.List;
 
 import static org.junit.Assert.*;
 
-public class DnsClassTest {
+public class DnsRecordTypeTest {
 
-    private static List<DnsClass> allTypes() throws Exception {
+    private static List<DnsRecordType> allTypes() throws Exception {
-        List<DnsClass> result = new ArrayList<DnsClass>();
+        List<DnsRecordType> result = new ArrayList<DnsRecordType>();
-        for (Field field : DnsClass.class.getDeclaredFields()) {
+        for (Field field : DnsRecordType.class.getFields()) {
-            if ((field.getModifiers() & Modifier.STATIC) != 0 && field.getType() == DnsClass.class) {
+            if ((field.getModifiers() & Modifier.STATIC) != 0 && field.getType() == DnsRecordType.class) {
-                result.add((DnsClass) field.get(null));
+                result.add((DnsRecordType) field.get(null));
             }
         }
         assertFalse(result.isEmpty());
@@ -41,26 +41,26 @@ public class DnsClassTest {
     @Test
     public void testSanity() throws Exception {
         assertEquals("More than one type has the same int value",
-                allTypes().size(), new HashSet<DnsClass>(allTypes()).size());
+                allTypes().size(), new HashSet<DnsRecordType>(allTypes()).size());
     }
 
     /**
-     * Test of hashCode method, of class DnsClass.
+     * Test of hashCode method, of class DnsRecordType.
      */
     @Test
     public void testHashCode() throws Exception {
-        for (DnsClass t : allTypes()) {
+        for (DnsRecordType t : allTypes()) {
             assertEquals(t.intValue(), t.hashCode());
         }
     }
 
     /**
-     * Test of equals method, of class DnsClass.
+     * Test of equals method, of class DnsRecordType.
      */
     @Test
     public void testEquals() throws Exception {
-        for (DnsClass t1 : allTypes()) {
+        for (DnsRecordType t1 : allTypes()) {
-            for (DnsClass t2 : allTypes()) {
+            for (DnsRecordType t2 : allTypes()) {
                 if (t1 != t2) {
                     assertNotEquals(t1, t2);
                 }
@@ -69,15 +69,15 @@ public class DnsClassTest {
     }
 
     /**
-     * Test of find method, of class DnsClass.
+     * Test of find method, of class DnsRecordType.
      */
     @Test
     public void testFind() throws Exception {
-        for (DnsClass t : allTypes()) {
+        for (DnsRecordType t : allTypes()) {
-            DnsClass found = DnsClass.valueOf(t.intValue());
+            DnsRecordType found = DnsRecordType.valueOf(t.intValue());
             assertSame(t, found);
-            found = DnsClass.valueOf(t.toString());
+            found = DnsRecordType.valueOf(t.name());
-            assertSame(t.toString(), t, found);
+            assertSame(t.name(), t, found);
         }
     }
 }

codec-dns/src/test/java/io/netty/handler/codec/dns/DnsResponseTest.java

@@ -17,16 +17,19 @@ package io.netty.handler.codec.dns;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
+import io.netty.channel.AddressedEnvelope;
 import io.netty.channel.embedded.EmbeddedChannel;
 import io.netty.channel.socket.DatagramPacket;
 import io.netty.handler.codec.CorruptedFrameException;
-import org.junit.Assert;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
 import java.net.InetSocketAddress;
 
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
 public class DnsResponseTest {
 
     private static final byte[][] packets = {
@@ -69,25 +72,23 @@ public class DnsResponseTest {
 
     @Test
     public void readResponseTest() throws Exception {
-        EmbeddedChannel embedder = new EmbeddedChannel(new DnsResponseDecoder());
+        EmbeddedChannel embedder = new EmbeddedChannel(new DatagramDnsResponseDecoder());
         for (byte[] p: packets) {
             ByteBuf packet = embedder.alloc().buffer(512).writeBytes(p);
             embedder.writeInbound(new DatagramPacket(packet, null, new InetSocketAddress(0)));
-            DnsResponse decoded = embedder.readInbound();
+            AddressedEnvelope<DnsResponse, InetSocketAddress> envelope = embedder.readInbound();
+            assertThat(envelope, is(instanceOf(DatagramDnsResponse.class)));
+            DnsResponse response = envelope.content();
+            assertThat(response, is(sameInstance((Object) envelope)));
+
             ByteBuf raw = Unpooled.wrappedBuffer(p);
-            Assert.assertEquals("Invalid id, expected: " + raw.getUnsignedShort(0) + ", actual: "
+            assertThat(response.id(), is(raw.getUnsignedShort(0)));
-                    + decoded.header().id(), raw.getUnsignedShort(0), decoded.header().id());
+            assertThat(response.count(DnsSection.QUESTION), is(raw.getUnsignedShort(4)));
-            Assert.assertEquals("Invalid resource count,  expected: " + raw.getUnsignedShort(4) + ", actual: "
+            assertThat(response.count(DnsSection.ANSWER), is(raw.getUnsignedShort(6)));
-                    + decoded.questions().size(), raw.getUnsignedShort(4), decoded.questions().size());
+            assertThat(response.count(DnsSection.AUTHORITY), is(raw.getUnsignedShort(8)));
-            Assert.assertEquals("Invalid resource count,  expected: " + raw.getUnsignedShort(6) + ", actual: "
+            assertThat(response.count(DnsSection.ADDITIONAL), is(raw.getUnsignedShort(10)));
-                    + decoded.answers().size(), raw.getUnsignedShort(6), decoded.answers().size());
+
-            Assert.assertEquals("Invalid resource count,  expected: " + raw.getUnsignedShort(8) + ", actual: "
+            envelope.release();
-                    + decoded.authorityResources().size(), raw.getUnsignedShort(8), decoded.authorityResources()
-                    .size());
-            Assert.assertEquals("Invalid resource count,  expected: " + raw.getUnsignedShort(10) + ", actual: "
-                    + decoded.additionalResources().size(), raw.getUnsignedShort(10),
-                    decoded.additionalResources().size());
-            decoded.release();
         }
     }
 
@@ -96,7 +97,7 @@ public class DnsResponseTest {
 
     @Test
     public void readMalormedResponseTest() throws Exception {
-        EmbeddedChannel embedder = new EmbeddedChannel(new DnsResponseDecoder());
+        EmbeddedChannel embedder = new EmbeddedChannel(new DatagramDnsResponseDecoder());
         ByteBuf packet = embedder.alloc().buffer(512).writeBytes(malformedLoopPacket);
         exception.expect(CorruptedFrameException.class);
         embedder.writeInbound(new DatagramPacket(packet, null, new InetSocketAddress(0)));

codec-dns/src/test/java/io/netty/handler/codec/dns/DnsTypeTest.java

@@ -1,83 +0,0 @@
-/*
- * Copyright 2014 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.handler.codec.dns;
-
-import org.junit.Test;
-
-import java.lang.reflect.Field;
-import java.lang.reflect.Modifier;
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-
-import static org.junit.Assert.*;
-
-public class DnsTypeTest {
-
-    private static List<DnsType> allTypes() throws Exception {
-        List<DnsType> result = new ArrayList<DnsType>();
-        for (Field field : DnsType.class.getFields()) {
-            if ((field.getModifiers() & Modifier.STATIC) != 0 && field.getType() == DnsType.class) {
-                result.add((DnsType) field.get(null));
-            }
-        }
-        assertFalse(result.isEmpty());
-        return result;
-    }
-
-    @Test
-    public void testSanity() throws Exception {
-        assertEquals("More than one type has the same int value",
-                allTypes().size(), new HashSet<DnsType>(allTypes()).size());
-    }
-
-    /**
-     * Test of hashCode method, of class DnsType.
-     */
-    @Test
-    public void testHashCode() throws Exception {
-        for (DnsType t : allTypes()) {
-            assertEquals(t.intValue(), t.hashCode());
-        }
-    }
-
-    /**
-     * Test of equals method, of class DnsType.
-     */
-    @Test
-    public void testEquals() throws Exception {
-        for (DnsType t1 : allTypes()) {
-            for (DnsType t2 : allTypes()) {
-                if (t1 != t2) {
-                    assertNotEquals(t1, t2);
-                }
-            }
-        }
-    }
-
-    /**
-     * Test of find method, of class DnsType.
-     */
-    @Test
-    public void testFind() throws Exception {
-        for (DnsType t : allTypes()) {
-            DnsType found = DnsType.valueOf(t.intValue());
-            assertSame(t, found);
-            found = DnsType.valueOf(t.toString());
-            assertSame(t.toString(), t, found);
-        }
-    }
-}

common/src/main/java/io/netty/util/internal/StringUtil.java

@@ -28,15 +28,19 @@ import static io.netty.util.internal.ObjectUtil.checkNotNull;
  */
 public final class StringUtil {
 
+    public static final String EMPTY_STRING = "";
     public static final String NEWLINE;
+
     public static final char DOUBLE_QUOTE = '\"';
     public static final char COMMA = ',';
     public static final char LINE_FEED = '\n';
     public static final char CARRIAGE_RETURN = '\r';
-    public static final String EMPTY_STRING = "";
+    public static final char TAB = '\t';
-    public static final byte UPPER_CASE_TO_LOWER_CASE_ASCII_OFFSET = (int) 'a' - (int) 'A';
+
+    public static final byte UPPER_CASE_TO_LOWER_CASE_ASCII_OFFSET = 'a' - 'A';
     private static final String[] BYTE2HEX_PAD = new String[256];
     private static final String[] BYTE2HEX_NOPAD = new String[256];
+
     /**
      * 2 - Quote character at beginning and end.
      * 5 - Extra allowance for anticipated escape characters that may be added.

resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolver.java

@@ -16,6 +16,7 @@
 package io.netty.resolver.dns;
 
 import io.netty.bootstrap.Bootstrap;
+import io.netty.channel.AddressedEnvelope;
 import io.netty.channel.ChannelFactory;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
@@ -27,13 +28,14 @@ import io.netty.channel.FixedRecvByteBufAllocator;
 import io.netty.channel.ReflectiveChannelFactory;
 import io.netty.channel.socket.DatagramChannel;
 import io.netty.channel.socket.InternetProtocolFamily;
-import io.netty.handler.codec.dns.DnsClass;
+import io.netty.handler.codec.dns.DatagramDnsQueryEncoder;
-import io.netty.handler.codec.dns.DnsQueryEncoder;
+import io.netty.handler.codec.dns.DatagramDnsResponse;
+import io.netty.handler.codec.dns.DatagramDnsResponseDecoder;
+import io.netty.handler.codec.dns.DnsSection;
 import io.netty.handler.codec.dns.DnsQuestion;
-import io.netty.handler.codec.dns.DnsResource;
+import io.netty.handler.codec.dns.DnsRecord;
 import io.netty.handler.codec.dns.DnsResponse;
 import io.netty.handler.codec.dns.DnsResponseCode;
-import io.netty.handler.codec.dns.DnsResponseDecoder;
 import io.netty.resolver.NameResolver;
 import io.netty.resolver.SimpleNameResolver;
 import io.netty.util.ReferenceCountUtil;
@@ -83,8 +85,8 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
         }
     }
 
-    private static final DnsResponseDecoder DECODER = new DnsResponseDecoder();
+    private static final DatagramDnsResponseDecoder DECODER = new DatagramDnsResponseDecoder();
-    private static final DnsQueryEncoder ENCODER = new DnsQueryEncoder();
+    private static final DatagramDnsQueryEncoder ENCODER = new DatagramDnsQueryEncoder();
 
     final Iterable<InetSocketAddress> nameServerAddresses;
     final ChannelFuture bindFuture;
@@ -117,7 +119,6 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
     private volatile int maxQueriesPerResolve = 8;
 
     private volatile int maxPayloadSize;
-    private volatile DnsClass maxPayloadSizeClass; // EDNS uses the CLASS field as the payload size field.
 
     /**
      * Creates a new DNS-based name resolver that communicates with a single DNS server.
@@ -580,16 +581,11 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
         }
 
         this.maxPayloadSize = maxPayloadSize;
-        maxPayloadSizeClass = DnsClass.valueOf(maxPayloadSize);
         ch.config().setRecvByteBufAllocator(new FixedRecvByteBufAllocator(maxPayloadSize));
 
         return this;
     }
 
-    DnsClass maxPayloadSizeClass() {
-        return maxPayloadSizeClass;
-    }
-
     /**
      * Clears all the DNS resource records cached by this resolver.
      *
@@ -662,21 +658,23 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
     /**
      * Sends a DNS query with the specified question.
      */
-    public Future<DnsResponse> query(DnsQuestion question) {
+    public Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> query(DnsQuestion question) {
         return query(nameServerAddresses, question);
     }
 
     /**
      * Sends a DNS query with the specified question.
      */
-    public Future<DnsResponse> query(DnsQuestion question, Promise<DnsResponse> promise) {
+    public Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> query(
+            DnsQuestion question, Promise<AddressedEnvelope<? extends DnsResponse, InetSocketAddress>> promise) {
         return query(nameServerAddresses, question, promise);
     }
 
     /**
      * Sends a DNS query with the specified question using the specified name server list.
      */
-    public Future<DnsResponse> query(Iterable<InetSocketAddress> nameServerAddresses, DnsQuestion question) {
+    public Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> query(
+            Iterable<InetSocketAddress> nameServerAddresses, DnsQuestion question) {
         if (nameServerAddresses == null) {
             throw new NullPointerException("nameServerAddresses");
         }
@@ -693,15 +691,18 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
                 return eventLoop.newFailedFuture(cachedResult.cause);
             }
         } else {
-            return query0(nameServerAddresses, question, eventLoop.<DnsResponse>newPromise());
+            return query0(
+                    nameServerAddresses, question,
+                    eventLoop.<AddressedEnvelope<? extends DnsResponse, InetSocketAddress>>newPromise());
         }
     }
 
     /**
      * Sends a DNS query with the specified question using the specified name server list.
      */
-    public Future<DnsResponse> query(
+    public Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> query(
-            Iterable<InetSocketAddress> nameServerAddresses, DnsQuestion question, Promise<DnsResponse> promise) {
+            Iterable<InetSocketAddress> nameServerAddresses, DnsQuestion question,
+            Promise<AddressedEnvelope<? extends DnsResponse, InetSocketAddress>> promise) {
 
         if (nameServerAddresses == null) {
             throw new NullPointerException("nameServerAddresses");
@@ -716,23 +717,25 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
         final DnsCacheEntry cachedResult = queryCache.get(question);
         if (cachedResult != null) {
             if (cachedResult.response != null) {
-                return promise.setSuccess(cachedResult.response.retain());
+                return cast(promise).setSuccess(cachedResult.response.retain());
             } else {
-                return promise.setFailure(cachedResult.cause);
+                return cast(promise).setFailure(cachedResult.cause);
             }
         } else {
             return query0(nameServerAddresses, question, promise);
         }
     }
 
-    private Future<DnsResponse> query0(
+    private Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> query0(
-            Iterable<InetSocketAddress> nameServerAddresses, DnsQuestion question, Promise<DnsResponse> promise) {
+            Iterable<InetSocketAddress> nameServerAddresses, DnsQuestion question,
+            Promise<AddressedEnvelope<? extends DnsResponse, InetSocketAddress>> promise) {
 
+        final Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> castPromise = cast(promise);
         try {
-            new DnsQueryContext(this, nameServerAddresses, question, promise).query();
+            new DnsQueryContext(this, nameServerAddresses, question, castPromise).query();
-            return promise;
+            return castPromise;
         } catch (Exception e) {
-            return promise.setFailure(e);
+            return castPromise.setFailure(e);
         }
     }
 
@@ -762,12 +765,22 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
         }
     }
 
+    @SuppressWarnings("unchecked")
+    private static Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> cast(Promise<?> promise) {
+        return (Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>>) promise;
+    }
+
+    @SuppressWarnings("unchecked")
+    private static AddressedEnvelope<DnsResponse, InetSocketAddress> cast(AddressedEnvelope<?, ?> envelope) {
+        return (AddressedEnvelope<DnsResponse, InetSocketAddress>) envelope;
+    }
+
     private final class DnsResponseHandler extends ChannelInboundHandlerAdapter {
         @Override
         public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
             try {
-                final DnsResponse res = (DnsResponse) msg;
+                final DatagramDnsResponse res = (DatagramDnsResponse) msg;
-                final int queryId = res.header().id();
+                final int queryId = res.id();
 
                 if (logger.isDebugEnabled()) {
                     logger.debug("{} RECEIVED: [{}: {}], {}", ch, queryId, res.sender(), res);
@@ -782,14 +795,13 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
                     return;
                 }
 
-                final List<DnsQuestion> questions = res.questions();
+                if (res.count(DnsSection.QUESTION) != 1) {
-                if (questions.size() != 1) {
                     logger.warn("Received a DNS response with invalid number of questions: {}", res);
                     return;
                 }
 
                 final DnsQuestion q = qCtx.question();
-                if (!q.equals(questions.get(0))) {
+                if (!q.equals(res.recordAt(DnsSection.QUESTION))) {
                     logger.warn("Received a mismatching DNS response: {}", res);
                     return;
                 }
@@ -800,26 +812,26 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
                     timeoutFuture.cancel(false);
                 }
 
-                if (res.header().responseCode() == DnsResponseCode.NOERROR) {
+                if (res.code() == DnsResponseCode.NOERROR) {
                     cache(q, res);
                     promises.set(queryId, null);
 
-                    Promise<DnsResponse> qPromise = qCtx.promise();
+                    Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> qPromise = qCtx.promise();
                     if (qPromise.setUncancellable()) {
-                        qPromise.setSuccess(res.retain());
+                        qPromise.setSuccess(cast(res.retain()));
                     }
                 } else {
                     qCtx.retry(res.sender(),
-                               "response code: " + res.header().responseCode() +
+                               "response code: " + res.code() +
-                               " with " + res.answers().size() + " answer(s) and " +
+                               " with " + res.count(DnsSection.ANSWER) + " answer(s) and " +
-                               res.authorityResources().size() + " authority resource(s)");
+                               res.count(DnsSection.AUTHORITY) + " authority resource(s)");
                 }
             } finally {
                 ReferenceCountUtil.safeRelease(msg);
             }
         }
 
-        private void cache(DnsQuestion question, DnsResponse res) {
+        private void cache(DnsQuestion question, AddressedEnvelope<? extends DnsResponse, InetSocketAddress> res) {
             final int maxTtl = maxTtl();
             if (maxTtl == 0) {
                 return;
@@ -827,8 +839,11 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
 
             long ttl = Long.MAX_VALUE;
             // Find the smallest TTL value returned by the server.
-            for (DnsResource r: res.answers()) {
+            final DnsResponse resc = res.content();
-                long rTtl = r.timeToLive();
+            final int answerCount = resc.count(DnsSection.ANSWER);
+            for (int i = 0; i < answerCount; i ++) {
+                final DnsRecord r = resc.recordAt(DnsSection.ANSWER, i);
+                final long rTtl = r.timeToLive();
                 if (ttl > rTtl) {
                     ttl = rTtl;
                 }
@@ -847,12 +862,13 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
     }
 
     static final class DnsCacheEntry {
-        final DnsResponse response;
+        final AddressedEnvelope<DnsResponse, InetSocketAddress> response;
         final Throwable cause;
         volatile ScheduledFuture<?> expirationFuture;
 
-        DnsCacheEntry(DnsResponse response) {
+        @SuppressWarnings("unchecked")
-            this.response = response.retain();
+        DnsCacheEntry(AddressedEnvelope<? extends DnsResponse, InetSocketAddress> response) {
+            this.response = (AddressedEnvelope<DnsResponse, InetSocketAddress>) response.retain();
             cause = null;
         }
 
@@ -862,7 +878,7 @@ public class DnsNameResolver extends SimpleNameResolver<InetSocketAddress> {
         }
 
         void release() {
-            DnsResponse response = this.response;
+            AddressedEnvelope<DnsResponse, InetSocketAddress> response = this.response;
             if (response != null) {
                 ReferenceCountUtil.safeRelease(response);
             }

resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolverContext.java

@@ -17,13 +17,17 @@
 package io.netty.resolver.dns;
 
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufHolder;
+import io.netty.channel.AddressedEnvelope;
 import io.netty.channel.socket.InternetProtocolFamily;
-import io.netty.handler.codec.dns.DnsClass;
+import io.netty.handler.codec.dns.DefaultDnsQuestion;
+import io.netty.handler.codec.dns.DefaultDnsRecordDecoder;
+import io.netty.handler.codec.dns.DnsSection;
 import io.netty.handler.codec.dns.DnsQuestion;
-import io.netty.handler.codec.dns.DnsResource;
+import io.netty.handler.codec.dns.DnsRawRecord;
+import io.netty.handler.codec.dns.DnsRecord;
+import io.netty.handler.codec.dns.DnsRecordType;
 import io.netty.handler.codec.dns.DnsResponse;
-import io.netty.handler.codec.dns.DnsResponseDecoder;
-import io.netty.handler.codec.dns.DnsType;
 import io.netty.util.CharsetUtil;
 import io.netty.util.ReferenceCountUtil;
 import io.netty.util.concurrent.Future;
@@ -51,14 +55,15 @@ final class DnsNameResolverContext {
     private static final int INADDRSZ4 = 4;
     private static final int INADDRSZ6 = 16;
 
-    private static final FutureListener<DnsResponse> RELEASE_RESPONSE = new FutureListener<DnsResponse>() {
+    private static final FutureListener<AddressedEnvelope<DnsResponse, InetSocketAddress>> RELEASE_RESPONSE =
-        @Override
+            new FutureListener<AddressedEnvelope<DnsResponse, InetSocketAddress>>() {
-        public void operationComplete(Future<DnsResponse> future) {
+                @Override
-            if (future.isSuccess()) {
+                public void operationComplete(Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> future) {
-                future.getNow().release();
+                    if (future.isSuccess()) {
-            }
+                        future.getNow().release();
-        }
+                    }
-    };
+                }
+            };
 
     private final DnsNameResolver parent;
     private final Promise<InetSocketAddress> promise;
@@ -67,8 +72,10 @@ final class DnsNameResolverContext {
     private final int maxAllowedQueries;
     private final InternetProtocolFamily[] resolveAddressTypes;
 
-    private final Set<Future<DnsResponse>> queriesInProgress =
+    private final Set<Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>> queriesInProgress =
-            Collections.newSetFromMap(new IdentityHashMap<Future<DnsResponse>, Boolean>());
+            Collections.newSetFromMap(
+                    new IdentityHashMap<Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>, Boolean>());
+
     private List<InetAddress> resolvedAddresses;
     private StringBuilder trace;
     private int allowedQueries;
@@ -87,19 +94,19 @@ final class DnsNameResolverContext {
 
     void resolve() {
         for (InternetProtocolFamily f: resolveAddressTypes) {
-            final DnsType type;
+            final DnsRecordType type;
             switch (f) {
             case IPv4:
-                type = DnsType.A;
+                type = DnsRecordType.A;
                 break;
             case IPv6:
-                type = DnsType.AAAA;
+                type = DnsRecordType.AAAA;
                 break;
             default:
                 throw new Error();
             }
 
-            query(parent.nameServerAddresses, new DnsQuestion(hostname, type));
+            query(parent.nameServerAddresses, new DefaultDnsQuestion(hostname, type));
         }
     }
 
@@ -110,12 +117,12 @@ final class DnsNameResolverContext {
 
         allowedQueries --;
 
-        final Future<DnsResponse> f = parent.query(nameServerAddresses, question);
+        final Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> f = parent.query(nameServerAddresses, question);
         queriesInProgress.add(f);
 
-        f.addListener(new FutureListener<DnsResponse>() {
+        f.addListener(new FutureListener<AddressedEnvelope<DnsResponse, InetSocketAddress>>() {
             @Override
-            public void operationComplete(Future<DnsResponse> future) throws Exception {
+            public void operationComplete(Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> future) {
                 queriesInProgress.remove(future);
 
                 if (promise.isDone()) {
@@ -135,12 +142,12 @@ final class DnsNameResolverContext {
         });
     }
 
-    void onResponse(final DnsQuestion question, final DnsResponse response) {
+    void onResponse(final DnsQuestion question, AddressedEnvelope<DnsResponse, InetSocketAddress> response) {
-        final DnsType type = question.type();
+        final DnsRecordType type = question.type();
         try {
-            if (type == DnsType.A || type == DnsType.AAAA) {
+            if (type == DnsRecordType.A || type == DnsRecordType.AAAA) {
                 onResponseAorAAAA(type, question, response);
-            } else if (type == DnsType.CNAME) {
+            } else if (type == DnsRecordType.CNAME) {
                 onResponseCNAME(question, response);
             }
         } finally {
@@ -148,14 +155,19 @@ final class DnsNameResolverContext {
         }
     }
 
-    private void onResponseAorAAAA(DnsType qType, DnsQuestion question, DnsResponse response) {
+    private void onResponseAorAAAA(
+            DnsRecordType qType, DnsQuestion question, AddressedEnvelope<DnsResponse, InetSocketAddress> envelope) {
+
         // We often get a bunch of CNAMES as well when we asked for A/AAAA.
+        final DnsResponse response = envelope.content();
         final Map<String, String> cnames = buildAliasMap(response);
+        final int answerCount = response.count(DnsSection.ANSWER);
 
         boolean found = false;
-        for (DnsResource r: response.answers()) {
+        for (int i = 0; i < answerCount; i ++) {
-            final DnsType type = r.type();
+            final DnsRecord r = response.recordAt(DnsSection.ANSWER, i);
-            if (type != DnsType.A && type != DnsType.AAAA) {
+            final DnsRecordType type = r.type();
+            if (type != DnsRecordType.A && type != DnsRecordType.AAAA) {
                 continue;
             }
 
@@ -178,7 +190,11 @@ final class DnsNameResolverContext {
                 }
             }
 
-            final ByteBuf content = r.content();
+            if (!(r instanceof DnsRawRecord)) {
+                continue;
+            }
+
+            final ByteBuf content = ((ByteBufHolder) r).content();
             final int contentLen = content.readableBytes();
             if (contentLen != INADDRSZ4 && contentLen != INADDRSZ6) {
                 continue;
@@ -204,20 +220,21 @@ final class DnsNameResolverContext {
             return;
         }
 
-        addTrace(response.sender(), "no matching " + qType + " record found");
+        addTrace(envelope.sender(), "no matching " + qType + " record found");
 
         // We aked for A/AAAA but we got only CNAME.
         if (!cnames.isEmpty()) {
-            onResponseCNAME(question, response, cnames, false);
+            onResponseCNAME(question, envelope, cnames, false);
         }
     }
 
-    private void onResponseCNAME(DnsQuestion question, DnsResponse response) {
+    private void onResponseCNAME(DnsQuestion question, AddressedEnvelope<DnsResponse, InetSocketAddress> envelope) {
-        onResponseCNAME(question, response, buildAliasMap(response), true);
+        onResponseCNAME(question, envelope, buildAliasMap(envelope.content()), true);
     }
 
     private void onResponseCNAME(
-            DnsQuestion question, DnsResponse response, Map<String, String> cnames, boolean trace) {
+            DnsQuestion question, AddressedEnvelope<DnsResponse, InetSocketAddress> response,
+            Map<String, String> cnames, boolean trace) {
 
         // Resolve the host name in the question into the real host name.
         final String name = question.name().toLowerCase(Locale.US);
@@ -241,15 +258,22 @@ final class DnsNameResolverContext {
     }
 
     private static Map<String, String> buildAliasMap(DnsResponse response) {
+        final int answerCount = response.count(DnsSection.ANSWER);
         Map<String, String> cnames = null;
-        for (DnsResource r: response.answers()) {
+        for (int i = 0; i < answerCount; i ++) {
-            final DnsType type = r.type();
+            final DnsRecord r = response.recordAt(DnsSection.ANSWER, i);
-            if (type != DnsType.CNAME) {
+            final DnsRecordType type = r.type();
+            if (type != DnsRecordType.CNAME) {
                 continue;
             }
 
-            String content = decodeDomainName(r.content());
+            if (!(r instanceof DnsRawRecord)) {
-            if (content == null) {
+                continue;
+            }
+
+            final ByteBuf recordContent = ((ByteBufHolder) r).content();
+            final String domainName = decodeDomainName(recordContent);
+            if (domainName == null) {
                 continue;
             }
 
@@ -257,7 +281,7 @@ final class DnsNameResolverContext {
                 cnames = new HashMap<String, String>();
             }
 
-            cnames.put(r.name().toLowerCase(Locale.US), content.toLowerCase(Locale.US));
+            cnames.put(r.name().toLowerCase(Locale.US), domainName.toLowerCase(Locale.US));
         }
 
         return cnames != null? cnames : Collections.<String, String>emptyMap();
@@ -281,7 +305,7 @@ final class DnsNameResolverContext {
             if (!triedCNAME) {
                 // As the last resort, try to query CNAME, just in case the name server has it.
                 triedCNAME = true;
-                query(parent.nameServerAddresses, new DnsQuestion(hostname, DnsType.CNAME, DnsClass.IN));
+                query(parent.nameServerAddresses, new DefaultDnsQuestion(hostname, DnsRecordType.CNAME));
                 return;
             }
         }
@@ -319,8 +343,9 @@ final class DnsNameResolverContext {
     private void finishResolve() {
         if (!queriesInProgress.isEmpty()) {
             // If there are queries in progress, we should cancel it because we already finished the resolution.
-            for (Iterator<Future<DnsResponse>> i = queriesInProgress.iterator(); i.hasNext();) {
+            for (Iterator<Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>> i = queriesInProgress.iterator();
-                Future<DnsResponse> f = i.next();
+                 i.hasNext();) {
+                Future<AddressedEnvelope<DnsResponse, InetSocketAddress>> f = i.next();
                 i.remove();
 
                 if (!f.cancel(false)) {
@@ -392,25 +417,32 @@ final class DnsNameResolverContext {
     }
 
     /**
-     * Adapted from {@link DnsResponseDecoder#readName(ByteBuf)}.
+     * Adapted from {@link DefaultDnsRecordDecoder#decodeName(ByteBuf)}.
      */
     static String decodeDomainName(ByteBuf buf) {
         buf.markReaderIndex();
         try {
             int position = -1;
             int checked = 0;
-            int length = buf.writerIndex();
+            final int end = buf.writerIndex();
-            StringBuilder name = new StringBuilder(64);
+            final StringBuilder name = new StringBuilder(buf.readableBytes() << 1);
             for (int len = buf.readUnsignedByte(); buf.isReadable() && len != 0; len = buf.readUnsignedByte()) {
                 boolean pointer = (len & 0xc0) == 0xc0;
                 if (pointer) {
                     if (position == -1) {
                         position = buf.readerIndex() + 1;
                     }
-                    buf.readerIndex((len & 0x3f) << 8 | buf.readUnsignedByte());
+
+                    final int next = (len & 0x3f) << 8 | buf.readUnsignedByte();
+                    if (next >= end) {
+                        // Should not happen.
+                        return null;
+                    }
+                    buf.readerIndex(next);
+
                     // check for loops
                     checked += 2;
-                    if (checked >= length) {
+                    if (checked >= end) {
                         // Name contains a loop; give up.
                         return null;
                     }
@@ -449,8 +481,8 @@ final class DnsNameResolverContext {
         trace.append(" CNAME ");
         trace.append(cname);
 
-        query(parent.nameServerAddresses, new DnsQuestion(cname, DnsType.A, DnsClass.IN));
+        query(parent.nameServerAddresses, new DefaultDnsQuestion(cname, DnsRecordType.A));
-        query(parent.nameServerAddresses, new DnsQuestion(cname, DnsType.AAAA, DnsClass.IN));
+        query(parent.nameServerAddresses, new DefaultDnsQuestion(cname, DnsRecordType.AAAA));
     }
 
     private void addTrace(InetSocketAddress nameServerAddr, String msg) {

resolver-dns/src/main/java/io/netty/resolver/dns/DnsQueryContext.java

@@ -17,13 +17,17 @@
 package io.netty.resolver.dns;
 
 import io.netty.buffer.Unpooled;
+import io.netty.channel.AddressedEnvelope;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.ChannelFutureListener;
+import io.netty.handler.codec.dns.DatagramDnsQuery;
+import io.netty.handler.codec.dns.DefaultDnsRawRecord;
+import io.netty.handler.codec.dns.DnsSection;
 import io.netty.handler.codec.dns.DnsQuery;
 import io.netty.handler.codec.dns.DnsQuestion;
-import io.netty.handler.codec.dns.DnsResource;
+import io.netty.handler.codec.dns.DnsRecord;
+import io.netty.handler.codec.dns.DnsRecordType;
 import io.netty.handler.codec.dns.DnsResponse;
-import io.netty.handler.codec.dns.DnsType;
 import io.netty.resolver.dns.DnsNameResolver.DnsCacheEntry;
 import io.netty.util.concurrent.Promise;
 import io.netty.util.concurrent.ScheduledFuture;
@@ -43,10 +47,10 @@ final class DnsQueryContext {
     private static final InternalLogger logger = InternalLoggerFactory.getInstance(DnsQueryContext.class);
 
     private final DnsNameResolver parent;
-    private final Promise<DnsResponse> promise;
+    private final Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> promise;
     private final int id;
     private final DnsQuestion question;
-    private final DnsResource optResource;
+    private final DnsRecord optResource;
     private final Iterator<InetSocketAddress> nameServerAddresses;
 
     private final boolean recursionDesired;
@@ -57,7 +61,7 @@ final class DnsQueryContext {
 
     DnsQueryContext(DnsNameResolver parent,
                     Iterable<InetSocketAddress> nameServerAddresses,
-                    DnsQuestion question, Promise<DnsResponse> promise) {
+                    DnsQuestion question, Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> promise) {
 
         this.parent = parent;
         this.promise = promise;
@@ -67,7 +71,8 @@ final class DnsQueryContext {
         recursionDesired = parent.isRecursionDesired();
         maxTries = parent.maxTriesPerQuery();
         remainingTries = maxTries;
-        optResource = new DnsResource("", DnsType.OPT, parent.maxPayloadSizeClass(), 0, Unpooled.EMPTY_BUFFER);
+        optResource = new DefaultDnsRawRecord(
+                StringUtil.EMPTY_STRING, DnsRecordType.OPT, parent.maxPayloadSize(), 0, Unpooled.EMPTY_BUFFER);
 
         this.nameServerAddresses = nameServerAddresses.iterator();
     }
@@ -89,7 +94,7 @@ final class DnsQueryContext {
         }
     }
 
-    Promise<DnsResponse> promise() {
+    Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> promise() {
         return promise;
     }
 
@@ -125,10 +130,10 @@ final class DnsQueryContext {
         remainingTries --;
 
         final InetSocketAddress nameServerAddr = nameServerAddresses.next();
-        final DnsQuery query = new DnsQuery(id, nameServerAddr);
+        final DatagramDnsQuery query = new DatagramDnsQuery(null, nameServerAddr, id);
-        query.addQuestion(question);
+        query.setRecursionDesired(recursionDesired);
-        query.header().setRecursionDesired(recursionDesired);
+        query.setRecord(DnsSection.QUESTION, question);
-        query.addAdditionalResource(optResource);
+        query.setRecord(DnsSection.ADDITIONAL, optResource);
 
         if (logger.isDebugEnabled()) {
             logger.debug("{} WRITE: [{}: {}], {}", parent.ch, id, nameServerAddr, question);

resolver-dns/src/test/java/io/netty/resolver/dns/DnsNameResolverTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 The Netty Project
+ * Copyright 2015 The Netty Project
  *
  * The Netty Project licenses this file to you under the Apache License,
  * version 2.0 (the "License"); you may not use this file except in compliance
@@ -13,18 +13,21 @@
  * License for the specific language governing permissions and limitations
  * under the License.
  */
-
 package io.netty.resolver.dns;
 
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufHolder;
+import io.netty.channel.AddressedEnvelope;
 import io.netty.channel.EventLoopGroup;
 import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.InternetProtocolFamily;
 import io.netty.channel.socket.nio.NioDatagramChannel;
-import io.netty.handler.codec.dns.DnsQuestion;
+import io.netty.handler.codec.dns.DefaultDnsQuestion;
-import io.netty.handler.codec.dns.DnsResource;
+import io.netty.handler.codec.dns.DnsSection;
+import io.netty.handler.codec.dns.DnsRecord;
+import io.netty.handler.codec.dns.DnsRecordType;
 import io.netty.handler.codec.dns.DnsResponse;
 import io.netty.handler.codec.dns.DnsResponseCode;
-import io.netty.handler.codec.dns.DnsType;
 import io.netty.util.concurrent.Future;
 import io.netty.util.internal.StringUtil;
 import io.netty.util.internal.ThreadLocalRandom;
@@ -181,7 +184,7 @@ public class DnsNameResolverTest {
                 EXCLUSIONS_RESOLVE_A,
                 "akamaihd.net",
                 "googleusercontent.com",
-                "");
+                StringUtil.EMPTY_STRING);
     }
 
     /**
@@ -236,7 +239,7 @@ public class DnsNameResolverTest {
                 "people.com.cn",
                 "googleusercontent.com",
                 "blogspot.in",
-                "");
+                StringUtil.EMPTY_STRING);
     }
 
     private static final EventLoopGroup group = new NioEventLoopGroup(1);
@@ -368,8 +371,8 @@ public class DnsNameResolverTest {
     public void testQueryMx() throws Exception {
         assertThat(resolver.isRecursionDesired(), is(true));
 
-        Map<String, Future<DnsResponse>> futures =
+        Map<String, Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>> futures =
-                new LinkedHashMap<String, Future<DnsResponse>>();
+                new LinkedHashMap<String, Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>>();
         for (String name: DOMAINS) {
             if (EXCLUSIONS_QUERY_MX.contains(name)) {
                 continue;
@@ -378,30 +381,36 @@ public class DnsNameResolverTest {
             queryMx(futures, name);
         }
 
-        for (Entry<String, Future<DnsResponse>> e: futures.entrySet()) {
+        for (Entry<String, Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>> e: futures.entrySet()) {
             String hostname = e.getKey();
-            DnsResponse response = e.getValue().sync().getNow();
+            AddressedEnvelope<DnsResponse, InetSocketAddress> envelope = e.getValue().sync().getNow();
+            DnsResponse response = envelope.content();
 
-            assertThat(response.header().responseCode(), is(DnsResponseCode.NOERROR));
+            assertThat(response.code(), is(DnsResponseCode.NOERROR));
-            List<DnsResource> mxList = new ArrayList<DnsResource>();
+
-            for (DnsResource r: response.answers()) {
+            final int answerCount = response.count(DnsSection.ANSWER);
-                if (r.type() == DnsType.MX) {
+            final List<DnsRecord> mxList = new ArrayList<DnsRecord>(answerCount);
+            for (int i = 0; i < answerCount; i ++) {
+                final DnsRecord r = response.recordAt(DnsSection.ANSWER, i);
+                if (r.type() == DnsRecordType.MX) {
                     mxList.add(r);
                 }
             }
 
             assertThat(mxList.size(), is(greaterThan(0)));
             StringBuilder buf = new StringBuilder();
-            for (DnsResource r: mxList) {
+            for (DnsRecord r: mxList) {
+                ByteBuf recordContent = ((ByteBufHolder) r).content();
+
                 buf.append(StringUtil.NEWLINE);
                 buf.append('\t');
                 buf.append(r.name());
                 buf.append(' ');
-                buf.append(r.type());
+                buf.append(r.type().name());
                 buf.append(' ');
-                buf.append(r.content().readUnsignedShort());
+                buf.append(recordContent.readUnsignedShort());
                 buf.append(' ');
-                buf.append(DnsNameResolverContext.decodeDomainName(r.content()));
+                buf.append(DnsNameResolverContext.decodeDomainName(recordContent));
             }
 
             logger.info("{} has the following MX records:{}", hostname, buf);
@@ -409,14 +418,17 @@ public class DnsNameResolverTest {
         }
     }
 
-    private static void resolve(Map<InetSocketAddress, Future<InetSocketAddress>> futures, String hostname) {
+    private static void resolve(
+            Map<InetSocketAddress, Future<InetSocketAddress>> futures, String hostname) {
         InetSocketAddress unresolved =
                 InetSocketAddress.createUnresolved(hostname, ThreadLocalRandom.current().nextInt(65536));
 
         futures.put(unresolved, resolver.resolve(unresolved));
     }
 
-    private static void queryMx(Map<String, Future<DnsResponse>> futures, String hostname) throws Exception {
+    private static void queryMx(
-        futures.put(hostname, resolver.query(new DnsQuestion(hostname, DnsType.MX)));
+            Map<String, Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>> futures,
+            String hostname) throws Exception {
+        futures.put(hostname, resolver.query(new DefaultDnsQuestion(hostname, DnsRecordType.MX)));
     }
 }

transport/src/main/java/io/netty/channel/DefaultAddressedEnvelope.java

@@ -43,6 +43,10 @@ public class DefaultAddressedEnvelope<M, A extends SocketAddress> implements Add
             throw new NullPointerException("message");
         }
 
+        if (recipient == null && sender == null) {
+            throw new NullPointerException("recipient and sender");
+        }
+
         this.message = message;
         this.sender = sender;
         this.recipient = recipient;