javasabr/mqtt-broker

Java implementation of MQTT 5.0 compatible broker based on RLib library.

mqtt-broker's Issues

Implement publishing with QoS 2

Implement publishing with QoS 2

Implement SSL connections

Implement SSL connections from external and internal clients.

Implement logic to validate all connect settings

Implement logic to validate all connect settings

Implement Simple Subscription Service

1. Create an interface SubscriptionService with methods:
   1.subscribe(mqttClient, topic)
   2.unsubscribe(mqttClient, topic)
   3.getSubscribers(topic)
2. Create s very simple implementation based on hash map with name SimpleSubscriptionService

Different re-send messages policies depend on MQTT version

With MQTT 5, brokers and clients are not allowed to retransmit MQTT messages for healthy TCP connections. The brokers and clients must re-send unacknowledged packets when the TCP connection was closed, though. So the QoS 1 and 2 guarantees are as important as with MQTT 3.1.1.

In case you rely on retransmission packets in your use case (e.g. because your implementation does not acknowledge packets in certain cases), we suggest reconsidering this decision before upgrading to MQTT 5.

Implement Simple Publishing Service

Create very simple publishing service for QoS 0

Update Subscription Service

From specs:
"When Clients make subscriptions with Topic Filters that include wildcards, it is possible for a Client’s subscriptions to overlap so that a published message might match multiple filters. In this case the Server MUST deliver the message to the Client respecting the maximum QoS of all the matching subscriptions [MQTT-3.3.4-2]. In addition, the Server MAY deliver further copies of the message, one for each additional matching subscription and respecting the subscription’s QoS in each case."

To implement this we need to do:

1. Change the method from Array getSubscribers(topicName) to void forEach(subscriber)-> {})
2. If we have wildcard subscriptions before to call the lambda, we need to find all repeated subscribers and to choose subscribers with higher QoS from them and to call the lambda only for uniq set of subscribers

Implement Simple Authentication Service

Implement Simple Authentication Service:

1. boolean auth(String username, byte[] password)

Remote code execution vulnerability CVE-2021-44228

Anyone who can connect to a deployed mqtt-broker can execute arbitrary code on the remote server instance!

mqtt-broker/build.gradle

Line 54 in 6d16b4e

implementation "org.springframework.boot:spring-boot-starter-log4j2:$springbootVersion"

https://www.cvedetails.com/cve/CVE-2021-44228/

Implement request limiters

Need to implement request limiters:

1. publish per external client
2. publish per internal client
3. publish for all external limits
4. publish for all internal limits

Improve MQTT5 properties support

Need to cover most MQTT5 properties.

Rework Subscription, Publishing and Authentication services for concurrent access

Implement shared subscriptions

Implement shared subscriptions

Update project structure

Need to move some packages to other packages

Additional difference in CONN packet between 3.1.1 and 5.0

For MQTT 3.1.1
If the Password Flag is set to 0, a password MUST NOT be present in the payload [MQTT-3.1.2-20].
If the Password Flag is set to 1, a password MUST be present in the payload [MQTT-3.1.2-21].
If the User Name Flag is set to 0, the Password Flag MUST be set to 0
For MQTT 5.0
The password flag is independent of the username flag.

Implement Simple Session Service

This service should map client id -> some session.
A session is a container of pending qos 1/2 packets.

Implement publishing with QoS 1

Implement publishing with QoS 1

Implement will topics

Implement will topics

Separate a client type into external and internal.

We should have two different server ports, the first port accepts only external clients (like devices and etc), the second port accepts internal clients(like services).

Implement Retained Messages

Need to implement Retained Messages:
https://www.hivemq.com/blog/mqtt-essentials-part-8-retained-messages/
https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901104

Need to update message expiration handling

https://www.hivemq.com/blog/mqtt5-essentials-part4-session-and-message-expiry/

Implement ACL Engine

Implement ACL Engine in EMQ style:

{allow, {user, "dashboard"}, subscribe, ["$SYS/#"]}.
{allow, all, publish, ["/smarthome/%c/temperature"]}.
{allow, {ipaddr, "10.211.55.10"}, pubsub, ["$SYS/#", "#"]}.
{deny, all, subscribe, ["$SYS/#", {eq, "#"}]}.

https://docs.emqx.io/tutorial/v3/en/security/acl.html

Implement Simple Client Id Registry

This service should provide the next API:

1. register/unregister client id
2. validate client id
3. check to exist of the client id
4. generate a new uniq client id