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https://issues.apache.org/jira/browse/AMQ-6680?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Timothy Bish resolved AMQ-6680.
-------------------------------
Resolution: Fixed
Assignee: Timothy Bish
Fix Version/s: 5.14.6
5.15.0
> MQTT over WebSocket doesn't work when WebSocket data frame contains partial
> or multiple MQTT control packets
> ------------------------------------------------------------------------------------------------------------
>
> Key: AMQ-6680
> URL: https://issues.apache.org/jira/browse/AMQ-6680
> Project: ActiveMQ
> Issue Type: Bug
> Components: MQTT, Transport
> Affects Versions: 5.14.5
> Reporter: Marco Geri
> Assignee: Timothy Bish
> Priority: Critical
> Labels: mqtt, patch, websocket
> Fix For: 5.15.0, 5.14.6
>
> Attachments: MQTTSocket-patch.txt, MQTTWSConnection-patch.txt,
> MQTTWSPartialFrameConnection.java, MQTTWSPartialFrameTest.java
>
>
> I tried to use the MQTT.js library in a browser but it didn't connect to
> ActiveMQ using MQTT-WebSocket transport.
> Debugging MQTT.js and ActiveMQ I found that the
> org.apache.activemq.transport.ws.jetty9.MQTTSocket class (in activemq-http
> module) assumes that a single WebSocket data frame +always+ contains a single
> MQTT Control Packet.
> This is the cause of MQTT.js failure because MQTT.js makes several send over
> WebSocket for a single MQTT Control Packet (header, length etc).
> Accordingly to MQTT OASIS specification (
> http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718127
> ):
> ??A single WebSocket data frame can contain multiple or partial MQTT Control
> Packets. The receiver MUST NOT assume that MQTT Control Packets are aligned
> on WebSocket frame boundaries.??
> And RFC 6455 ( https://www.ietf.org/rfc/rfc6455.txt ):
> ??The WebSocket message does not necessarily correspond to a particular
> network layer framing, as a fragmented message may be coalesced or split by
> an intermediary.??
> So I think that ActiveMQ should be fixed to be compliant to the WebSocket and
> MQTT specifications.
> I attached the diff patch file for MQTTSocket which fixes the problem and a
> new activemq-http module MQTT-WebSocket unit test for this issue (the same of
> MQTTWSTransportTest but which splits MQTT Frame Packet in multiple WebSocket
> frames):
> MQTTWSPartialFrameConnection.java
> MQTTWSPartialFrameTest.java
> When writing the unit test I found also a bug in the class
> org.apache.activemq.transport.ws.MQTTWSConnection.java.
> All the occurrences of:
> {code:java}
> ByteSequence payload = wireFormat.marshal(command.encode());
> connection.getRemote().sendBytes(ByteBuffer.wrap(payload.data));
> {code}
>
> should be replaced with:
> {code:java}
> ByteSequence payload = wireFormat.marshal(command.encode());
> connection.getRemote().sendBytes(ByteBuffer.wrap(payload.data,
> payload.offset, payload.length));
> {code}
> That is because of the payload.data bytes array buffer in ByteSequenze is
> bigger than the real MQTT frame packed bytes size, so sending all the
> payload.data bytes array, ActiveMQ receives much more extra zero-extra bytes.
> With the current implementation, those extra zero-bytes are ignored and this
> makes wrongly passes the test (while it should fail because there are "extra
> bytes" which doesn't respect the MQTT protocol).
> I attached also the diff patch file for the MQTTWSConnection file.
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