901c66fa81
Motivation: The MQTT decoder should raise an exception trying to build a CONNECT packet where password field is set but not the username one (as by MQTT 3.1/3.1.1 spec). Modification: Throw exception if password field is set but not the username Result: Fixes [#7205].
398 lines
15 KiB
Java
398 lines
15 KiB
Java
/*
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* Copyright 2014 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.mqtt;
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import io.netty.buffer.ByteBuf;
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import io.netty.buffer.ByteBufAllocator;
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import io.netty.channel.ChannelHandler;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.handler.codec.DecoderException;
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import io.netty.handler.codec.MessageToMessageEncoder;
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import io.netty.util.CharsetUtil;
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import io.netty.util.internal.EmptyArrays;
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import java.util.List;
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import static io.netty.handler.codec.mqtt.MqttCodecUtil.*;
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/**
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* Encodes Mqtt messages into bytes following the protocol specification v3.1
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* as described here <a href="http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/mqtt-v3r1.html">MQTTV3.1</a>
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*/
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@ChannelHandler.Sharable
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public final class MqttEncoder extends MessageToMessageEncoder<MqttMessage> {
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public static final MqttEncoder INSTANCE = new MqttEncoder();
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private MqttEncoder() { }
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@Override
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protected void encode(ChannelHandlerContext ctx, MqttMessage msg, List<Object> out) throws Exception {
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out.add(doEncode(ctx.alloc(), msg));
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}
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/**
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* This is the main encoding method.
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* It's only visible for testing.
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*
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* @param byteBufAllocator Allocates ByteBuf
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* @param message MQTT message to encode
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* @return ByteBuf with encoded bytes
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*/
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static ByteBuf doEncode(ByteBufAllocator byteBufAllocator, MqttMessage message) {
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switch (message.fixedHeader().messageType()) {
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case CONNECT:
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return encodeConnectMessage(byteBufAllocator, (MqttConnectMessage) message);
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case CONNACK:
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return encodeConnAckMessage(byteBufAllocator, (MqttConnAckMessage) message);
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case PUBLISH:
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return encodePublishMessage(byteBufAllocator, (MqttPublishMessage) message);
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case SUBSCRIBE:
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return encodeSubscribeMessage(byteBufAllocator, (MqttSubscribeMessage) message);
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case UNSUBSCRIBE:
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return encodeUnsubscribeMessage(byteBufAllocator, (MqttUnsubscribeMessage) message);
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case SUBACK:
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return encodeSubAckMessage(byteBufAllocator, (MqttSubAckMessage) message);
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case UNSUBACK:
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case PUBACK:
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case PUBREC:
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case PUBREL:
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case PUBCOMP:
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return encodeMessageWithOnlySingleByteFixedHeaderAndMessageId(byteBufAllocator, message);
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case PINGREQ:
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case PINGRESP:
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case DISCONNECT:
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return encodeMessageWithOnlySingleByteFixedHeader(byteBufAllocator, message);
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default:
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throw new IllegalArgumentException(
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"Unknown message type: " + message.fixedHeader().messageType().value());
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}
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}
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private static ByteBuf encodeConnectMessage(
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ByteBufAllocator byteBufAllocator,
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MqttConnectMessage message) {
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int payloadBufferSize = 0;
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MqttFixedHeader mqttFixedHeader = message.fixedHeader();
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MqttConnectVariableHeader variableHeader = message.variableHeader();
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MqttConnectPayload payload = message.payload();
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MqttVersion mqttVersion = MqttVersion.fromProtocolNameAndLevel(variableHeader.name(),
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(byte) variableHeader.version());
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// as MQTT 3.1 & 3.1.1 spec, If the User Name Flag is set to 0, the Password Flag MUST be set to 0
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if (!variableHeader.hasUserName() && variableHeader.hasPassword()) {
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throw new DecoderException("Without a username, the password MUST be not set");
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}
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// Client id
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String clientIdentifier = payload.clientIdentifier();
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if (!isValidClientId(mqttVersion, clientIdentifier)) {
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throw new MqttIdentifierRejectedException("invalid clientIdentifier: " + clientIdentifier);
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}
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byte[] clientIdentifierBytes = encodeStringUtf8(clientIdentifier);
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payloadBufferSize += 2 + clientIdentifierBytes.length;
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// Will topic and message
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String willTopic = payload.willTopic();
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byte[] willTopicBytes = willTopic != null ? encodeStringUtf8(willTopic) : EmptyArrays.EMPTY_BYTES;
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byte[] willMessage = payload.willMessageInBytes();
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byte[] willMessageBytes = willMessage != null ? willMessage : EmptyArrays.EMPTY_BYTES;
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if (variableHeader.isWillFlag()) {
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payloadBufferSize += 2 + willTopicBytes.length;
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payloadBufferSize += 2 + willMessageBytes.length;
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}
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String userName = payload.userName();
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byte[] userNameBytes = userName != null ? encodeStringUtf8(userName) : EmptyArrays.EMPTY_BYTES;
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if (variableHeader.hasUserName()) {
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payloadBufferSize += 2 + userNameBytes.length;
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}
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byte[] password = payload.passwordInBytes();
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byte[] passwordBytes = password != null ? password : EmptyArrays.EMPTY_BYTES;
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if (variableHeader.hasPassword()) {
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payloadBufferSize += 2 + passwordBytes.length;
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}
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// Fixed header
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byte[] protocolNameBytes = mqttVersion.protocolNameBytes();
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int variableHeaderBufferSize = 2 + protocolNameBytes.length + 4;
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int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
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int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
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ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
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buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
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writeVariableLengthInt(buf, variablePartSize);
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buf.writeShort(protocolNameBytes.length);
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buf.writeBytes(protocolNameBytes);
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buf.writeByte(variableHeader.version());
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buf.writeByte(getConnVariableHeaderFlag(variableHeader));
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buf.writeShort(variableHeader.keepAliveTimeSeconds());
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// Payload
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buf.writeShort(clientIdentifierBytes.length);
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buf.writeBytes(clientIdentifierBytes, 0, clientIdentifierBytes.length);
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if (variableHeader.isWillFlag()) {
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buf.writeShort(willTopicBytes.length);
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buf.writeBytes(willTopicBytes, 0, willTopicBytes.length);
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buf.writeShort(willMessageBytes.length);
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buf.writeBytes(willMessageBytes, 0, willMessageBytes.length);
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}
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if (variableHeader.hasUserName()) {
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buf.writeShort(userNameBytes.length);
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buf.writeBytes(userNameBytes, 0, userNameBytes.length);
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}
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if (variableHeader.hasPassword()) {
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buf.writeShort(passwordBytes.length);
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buf.writeBytes(passwordBytes, 0, passwordBytes.length);
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}
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return buf;
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}
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private static int getConnVariableHeaderFlag(MqttConnectVariableHeader variableHeader) {
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int flagByte = 0;
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if (variableHeader.hasUserName()) {
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flagByte |= 0x80;
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}
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if (variableHeader.hasPassword()) {
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flagByte |= 0x40;
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}
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if (variableHeader.isWillRetain()) {
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flagByte |= 0x20;
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}
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flagByte |= (variableHeader.willQos() & 0x03) << 3;
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if (variableHeader.isWillFlag()) {
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flagByte |= 0x04;
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}
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if (variableHeader.isCleanSession()) {
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flagByte |= 0x02;
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}
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return flagByte;
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}
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private static ByteBuf encodeConnAckMessage(
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ByteBufAllocator byteBufAllocator,
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MqttConnAckMessage message) {
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ByteBuf buf = byteBufAllocator.buffer(4);
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buf.writeByte(getFixedHeaderByte1(message.fixedHeader()));
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buf.writeByte(2);
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buf.writeByte(message.variableHeader().isSessionPresent() ? 0x01 : 0x00);
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buf.writeByte(message.variableHeader().connectReturnCode().byteValue());
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return buf;
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}
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private static ByteBuf encodeSubscribeMessage(
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ByteBufAllocator byteBufAllocator,
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MqttSubscribeMessage message) {
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int variableHeaderBufferSize = 2;
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int payloadBufferSize = 0;
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MqttFixedHeader mqttFixedHeader = message.fixedHeader();
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MqttMessageIdVariableHeader variableHeader = message.variableHeader();
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MqttSubscribePayload payload = message.payload();
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for (MqttTopicSubscription topic : payload.topicSubscriptions()) {
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String topicName = topic.topicName();
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byte[] topicNameBytes = encodeStringUtf8(topicName);
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payloadBufferSize += 2 + topicNameBytes.length;
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payloadBufferSize += 1;
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}
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int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
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int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
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ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
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buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
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writeVariableLengthInt(buf, variablePartSize);
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// Variable Header
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int messageId = variableHeader.messageId();
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buf.writeShort(messageId);
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// Payload
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for (MqttTopicSubscription topic : payload.topicSubscriptions()) {
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String topicName = topic.topicName();
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byte[] topicNameBytes = encodeStringUtf8(topicName);
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buf.writeShort(topicNameBytes.length);
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buf.writeBytes(topicNameBytes, 0, topicNameBytes.length);
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buf.writeByte(topic.qualityOfService().value());
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}
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return buf;
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}
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private static ByteBuf encodeUnsubscribeMessage(
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ByteBufAllocator byteBufAllocator,
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MqttUnsubscribeMessage message) {
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int variableHeaderBufferSize = 2;
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int payloadBufferSize = 0;
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MqttFixedHeader mqttFixedHeader = message.fixedHeader();
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MqttMessageIdVariableHeader variableHeader = message.variableHeader();
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MqttUnsubscribePayload payload = message.payload();
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for (String topicName : payload.topics()) {
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byte[] topicNameBytes = encodeStringUtf8(topicName);
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payloadBufferSize += 2 + topicNameBytes.length;
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}
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int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
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int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
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ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
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buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
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writeVariableLengthInt(buf, variablePartSize);
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// Variable Header
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int messageId = variableHeader.messageId();
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buf.writeShort(messageId);
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// Payload
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for (String topicName : payload.topics()) {
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byte[] topicNameBytes = encodeStringUtf8(topicName);
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buf.writeShort(topicNameBytes.length);
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buf.writeBytes(topicNameBytes, 0, topicNameBytes.length);
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}
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return buf;
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}
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private static ByteBuf encodeSubAckMessage(
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ByteBufAllocator byteBufAllocator,
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MqttSubAckMessage message) {
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int variableHeaderBufferSize = 2;
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int payloadBufferSize = message.payload().grantedQoSLevels().size();
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int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
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int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
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ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
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buf.writeByte(getFixedHeaderByte1(message.fixedHeader()));
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writeVariableLengthInt(buf, variablePartSize);
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buf.writeShort(message.variableHeader().messageId());
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for (int qos : message.payload().grantedQoSLevels()) {
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buf.writeByte(qos);
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}
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return buf;
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}
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private static ByteBuf encodePublishMessage(
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ByteBufAllocator byteBufAllocator,
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MqttPublishMessage message) {
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MqttFixedHeader mqttFixedHeader = message.fixedHeader();
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MqttPublishVariableHeader variableHeader = message.variableHeader();
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ByteBuf payload = message.payload().duplicate();
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String topicName = variableHeader.topicName();
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byte[] topicNameBytes = encodeStringUtf8(topicName);
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int variableHeaderBufferSize = 2 + topicNameBytes.length +
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(mqttFixedHeader.qosLevel().value() > 0 ? 2 : 0);
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int payloadBufferSize = payload.readableBytes();
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int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
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int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
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ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
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buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
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writeVariableLengthInt(buf, variablePartSize);
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buf.writeShort(topicNameBytes.length);
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buf.writeBytes(topicNameBytes);
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if (mqttFixedHeader.qosLevel().value() > 0) {
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buf.writeShort(variableHeader.messageId());
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}
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buf.writeBytes(payload);
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return buf;
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}
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private static ByteBuf encodeMessageWithOnlySingleByteFixedHeaderAndMessageId(
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ByteBufAllocator byteBufAllocator,
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MqttMessage message) {
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MqttFixedHeader mqttFixedHeader = message.fixedHeader();
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MqttMessageIdVariableHeader variableHeader = (MqttMessageIdVariableHeader) message.variableHeader();
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int msgId = variableHeader.messageId();
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int variableHeaderBufferSize = 2; // variable part only has a message id
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int fixedHeaderBufferSize = 1 + getVariableLengthInt(variableHeaderBufferSize);
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ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variableHeaderBufferSize);
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buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
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writeVariableLengthInt(buf, variableHeaderBufferSize);
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buf.writeShort(msgId);
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return buf;
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}
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private static ByteBuf encodeMessageWithOnlySingleByteFixedHeader(
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ByteBufAllocator byteBufAllocator,
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MqttMessage message) {
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MqttFixedHeader mqttFixedHeader = message.fixedHeader();
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ByteBuf buf = byteBufAllocator.buffer(2);
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buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
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buf.writeByte(0);
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return buf;
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}
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private static int getFixedHeaderByte1(MqttFixedHeader header) {
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int ret = 0;
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ret |= header.messageType().value() << 4;
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if (header.isDup()) {
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ret |= 0x08;
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}
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ret |= header.qosLevel().value() << 1;
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if (header.isRetain()) {
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ret |= 0x01;
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}
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return ret;
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}
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private static void writeVariableLengthInt(ByteBuf buf, int num) {
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do {
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int digit = num % 128;
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num /= 128;
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if (num > 0) {
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digit |= 0x80;
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}
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buf.writeByte(digit);
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} while (num > 0);
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}
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private static int getVariableLengthInt(int num) {
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int count = 0;
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do {
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num /= 128;
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count++;
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} while (num > 0);
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return count;
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}
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private static byte[] encodeStringUtf8(String s) {
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return s.getBytes(CharsetUtil.UTF_8);
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}
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}
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