com.hivemq.codec.decoder.AbstractMqttPublishDecoder Maven / Gradle / Ivy
Show all versions of hivemq-community-edition-embedded Show documentation
/*
* Copyright 2019-present HiveMQ GmbH
*
* Licensed 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 com.hivemq.codec.decoder;
import com.google.common.base.Utf8;
import com.hivemq.bootstrap.ClientConnectionContext;
import com.hivemq.codec.encoder.mqtt5.Mqtt5PayloadFormatIndicator;
import com.hivemq.configuration.service.FullConfigurationService;
import com.hivemq.extension.sdk.api.annotations.NotNull;
import com.hivemq.extension.sdk.api.annotations.Nullable;
import com.hivemq.mqtt.handler.disconnect.MqttServerDisconnector;
import com.hivemq.mqtt.message.Message;
import com.hivemq.mqtt.message.reason.Mqtt5DisconnectReasonCode;
import com.hivemq.util.Bytes;
import com.hivemq.util.ReasonStrings;
import io.netty.buffer.ByteBuf;
/**
* @author Florian Limpöck
*/
public abstract class AbstractMqttPublishDecoder extends AbstractMqttDecoder {
private static final byte @NotNull [] EMPTY_PAYLOAD = new byte[0];
protected AbstractMqttPublishDecoder(
final @NotNull MqttServerDisconnector disconnector,
final @NotNull FullConfigurationService configurationService) {
super(disconnector, configurationService);
}
/**
* Decodes and validates the quality of service (QoS) from the publish header
*
* Results in {@link Mqtt5DisconnectReasonCode#MALFORMED_PACKET} with DISCONNECT by:
*
* - qos = 3
*
* @param clientConnectionContext the connection of the mqtt client
* @param header the publish header byte
* @return the QoS, or -1 if this method disconnected.
*/
protected int decodeQoS(final @NotNull ClientConnectionContext clientConnectionContext, final byte header) {
final int qos = (header & 0b0000_0110) >> 1;
if (qos == 3) {
disconnector.disconnect(clientConnectionContext.getChannel(),
"A client (IP: {}) sent a PUBLISH with an invalid QoS. Disconnecting client.",
"Sent a PUBLISH with an invalid QoS",
Mqtt5DisconnectReasonCode.MALFORMED_PACKET,
ReasonStrings.DISCONNECT_MALFORMED_PUBLISH_QOS_3);
return DISCONNECTED;
}
return qos;
}
/**
* Decodes and validates the duplicate delivery flag from the publish header
*
* Results in {@link Mqtt5DisconnectReasonCode#PROTOCOL_ERROR} with DISCONNECT by:
*
* - qos == 0 AND dup == true
*
* @param clientConnectionContext the connection of the mqtt client
* @param header the publish header byte
* @param qos the quality of service of the publish
* @return whether the DUP flag is set or {@code null} if this method disconnected.
*/
protected @Nullable Boolean decodeDup(
final @NotNull ClientConnectionContext clientConnectionContext, final byte header, final int qos) {
final boolean dup = Bytes.isBitSet(header, 3);
if (qos == 0 && dup) {
disconnector.disconnect(clientConnectionContext.getChannel(),
"A client (IP: {}) sent a PUBLISH with QoS 0 and DUP set to 1. Disconnecting client.",
"Sent a PUBLISH with QoS 0 and DUP set to 1",
Mqtt5DisconnectReasonCode.PROTOCOL_ERROR,
ReasonStrings.DISCONNECT_PROTOCOL_ERROR_PUBLISH_QOS_0_DP);
return null;
}
return dup;
}
/**
* Decodes the retain flag from the publish header
*
* Results in {@link Mqtt5DisconnectReasonCode#RETAIN_NOT_SUPPORTED} with DISCONNECT by:
*
* - retained == true AND configured retainedMessagesSupported == false
*
* @param clientConnectionContext the connection of the mqtt client
* @param header the publish header byte
* @return whether the RETAIN flag is set or {@code null} if this method disconnected.
*/
protected @Nullable Boolean decodeRetain(
final @NotNull ClientConnectionContext clientConnectionContext, final byte header) {
final boolean retained = Bytes.isBitSet(header, 0);
if (retained && !configurationService.mqttConfiguration().retainedMessagesEnabled()) {
disconnector.disconnect(clientConnectionContext.getChannel(),
"A client (IP: {}) sent a PUBLISH with retain set to 1 although retain is not available. Disconnecting client.",
"Sent a PUBLISH with retain set to 1 although retain is not available",
Mqtt5DisconnectReasonCode.RETAIN_NOT_SUPPORTED,
ReasonStrings.DISCONNECT_RETAIN_NOT_SUPPORTED);
return null;
}
return retained;
}
/**
* Decodes and validates the packet identifier of the publish
*
* Note: use only for QoS > 0
*
* Results in {@link Mqtt5DisconnectReasonCode#PROTOCOL_ERROR} with DISCONNECT by:
*
* - packet identifier == 0F
*
* @param clientConnectionContext the connection of the mqtt client
* @param buf the encoded ByteBuf of the message
* @return the packet identifier or 0 if this method disconnected.
*/
protected int decodePacketIdentifier(
final @NotNull ClientConnectionContext clientConnectionContext, final @NotNull ByteBuf buf) {
final int packetIdentifier = buf.readUnsignedShort();
if (packetIdentifier == 0) {
disconnector.disconnect(clientConnectionContext.getChannel(),
"A client (IP: {}) sent a PUBLISH with QoS > 0 and packet identifier 0. Disconnecting client.",
"Sent a PUBLISH with QoS > 0 and packet identifier 0",
Mqtt5DisconnectReasonCode.PROTOCOL_ERROR,
ReasonStrings.DISCONNECT_PROTOCOL_ERROR_PUBLISH_ID_ZERO);
}
return packetIdentifier;
}
/**
* Decodes and optionally validates a publish payload
*
* Results in {@link Mqtt5DisconnectReasonCode#PAYLOAD_FORMAT_INVALID} with DISCONNECT by:
*
* - payloadFormatIndicator == UTF-8 AND validatePayloadFormat = true AND payload is not UTF-8 well formed.
*
* @param clientConnectionContext the connection of the mqtt client
* @param buf the encoded ByteBuf of the message
* @param payloadLength the length of the payload
* @param payloadFormatIndicator the nullable {@link Mqtt5PayloadFormatIndicator}
* @param validatePayloadFormat the configured boolean for payload validation (default false)
* @return the payload as a byte[] or {@code null} if this method disconnected.
*/
protected byte @Nullable [] decodePayload(
final @NotNull ClientConnectionContext clientConnectionContext,
final @NotNull ByteBuf buf,
final int payloadLength,
final @Nullable Mqtt5PayloadFormatIndicator payloadFormatIndicator,
final boolean validatePayloadFormat) {
final byte[] payload;
if (payloadLength > 0) {
payload = new byte[payloadLength];
buf.readBytes(payload);
if (payloadFormatIndicator == Mqtt5PayloadFormatIndicator.UTF_8) {
if (validatePayloadFormat) {
if (!Utf8.isWellFormed(payload)) {
disconnector.disconnect(clientConnectionContext.getChannel(),
"A client (IP: {}) sent a PUBLISH with an invalid UTF-8 payload. This is not allowed. Disconnecting client.",
"Sent a PUBLISH with an invalid UTF-8 payload",
Mqtt5DisconnectReasonCode.PAYLOAD_FORMAT_INVALID,
ReasonStrings.DISCONNECT_PAYLOAD_FORMAT_INVALID_PUBLISH);
return null;
}
}
}
} else {
payload = EMPTY_PAYLOAD;
}
return payload;
}
}