[jira] [Updated] (AMQ-5092) MQTT uses duplicate packet IDs for PUBLISH messages

["Dhiraj Bokde (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AMQ-5092?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Dhiraj Bokde updated AMQ-5092:
------------------------------

    Attachment: AMQ-5092.patch

Patch to fix MQTT publish packet id generation

> MQTT uses duplicate packet IDs for PUBLISH messages
> ---------------------------------------------------
>
>                 Key: AMQ-5092
>                 URL: https://issues.apache.org/jira/browse/AMQ-5092
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: MQTT
>    Affects Versions: 5.9.0
>            Reporter: Dhiraj Bokde
>             Fix For: 5.10.0
>
>         Attachments: AMQ-5092.patch
>
>
> MQTT protocol converters does not correctly generate unique packet ids for retained and non-retained publish messages sent to clients. MQTT requires that all Publish messages with QoS > 0 must have a unique packet id which can be used by clients to coordinate the PUBACK, PUBREC, PUBREL and PUBCOMP messages depending upon the QoS flow. 
> Although retained messages published on creation of client subscriptions are copies of retained messages, they must carry a unique packet id when dispatched to clients. ActiveMQ re-uses the retained message's packet id, which makes it difficult to acknowledge these messages when wildcard topics are used. 
> ActiveMQ also sends the same non-retained message multiple times for every matching subscription for overlapping subscriptions. These messages also re-use the publisher's message id as the packet id, which breaks client acknowledgment. 
> A patch is included, which fixes all the above scenarios. It generates a unique packet id for every publish (retained and non-retained), and also ensures that redelivery on the same connection will re-use message ids, with the dup flag set. The patch also maps JMS redelivery status for a subscription to the MQTT Dup flag to indicate duplicate messages. Unit tests are included to test correct packet id generation. 



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