CoreLink Parsing issue ?

[sbernard31]

I maybe find a but playing with leshan server demo ...
Need to investigate !

026-03-06 16:45:15,236 EventServlet         [WARN] Unable to handle notification of [DQXcqcBuHZ:/3442/0]  
org.eclipse.leshan.core.request.exception.InvalidResponseException: Unable to decode notification payload  of observation [SingleObservation [path=/3442/0, id=Ox51ea0f8bc409674c[coap://[0:0:0:0:0:0:0:0]:5683], contentFormat=TLV(11542), registrationId=DQXcqcBuHZ, context={}]] 
    at org.eclipse.leshan.transport.californium.server.endpoint.ServerCoapMessageTranslator.createObserveResponse(ServerCoapMessageTranslator.java:154)
    at org.eclipse.leshan.transport.californium.server.endpoint.CaliforniumServerEndpointsProvider.lambda$createEndpoints$0(CaliforniumServerEndpointsProvider.java:178)
    at org.eclipse.californium.core.network.CoapEndpoint$NotificationDispatcher.accept(CoapEndpoint.java:800)
    at org.eclipse.californium.core.network.CoapEndpoint$NotificationDispatcher.accept(CoapEndpoint.java:791)
    at org.eclipse.californium.core.network.BaseMatcher$2.onResponse(BaseMatcher.java:251)
    at org.eclipse.californium.core.coap.Request.setResponse(Request.java:923)
    at org.eclipse.californium.core.server.ServerMessageDeliverer.deliverResponse(ServerMessageDeliverer.java:268)
    at org.eclipse.californium.core.network.stack.BaseCoapStack$StackTopAdapter.receiveResponse(BaseCoapStack.java:214)
    at org.eclipse.californium.core.network.stack.AbstractLayer.receiveResponse(AbstractLayer.java:85)
    at org.eclipse.californium.oscore.ObjectSecurityContextLayer.receiveResponse(ObjectSecurityContextLayer.java:274)
    at org.eclipse.californium.core.network.stack.AbstractLayer.receiveResponse(AbstractLayer.java:85)
    at org.eclipse.californium.core.network.stack.ExchangeCleanupLayer.receiveResponse(ExchangeCleanupLayer.java:105)
    at org.eclipse.californium.core.network.stack.ObserveLayer.receiveResponse(ObserveLayer.java:154)
    at org.eclipse.californium.core.network.stack.BlockwiseLayer.handleBlock2Response(BlockwiseLayer.java:1202)
    at org.eclipse.californium.core.network.stack.BlockwiseLayer.receiveResponse(BlockwiseLayer.java:843)
    at org.eclipse.californium.core.network.stack.AbstractLayer.receiveResponse(AbstractLayer.java:85)
    at org.eclipse.californium.oscore.ObjectSecurityLayer.receiveResponse(ObjectSecurityLayer.java:367)
    at org.eclipse.californium.core.network.stack.ReliabilityLayer.receiveResponse(ReliabilityLayer.java:321)
    at org.eclipse.californium.core.network.stack.AbstractLayer.receiveResponse(AbstractLayer.java:85)
    at org.eclipse.californium.core.network.stack.BaseCoapStack.receiveResponse(BaseCoapStack.java:132)
    at org.eclipse.californium.core.network.CoapEndpoint$1.receiveResponse(CoapEndpoint.java:326)
    at org.eclipse.californium.core.network.UdpMatcher$4.run(UdpMatcher.java:465)
    at org.eclipse.californium.elements.util.SerialExecutor.run(SerialExecutor.java:323)
    at org.eclipse.californium.elements.util.SerialExecutor.lambda$scheduleNextJob$0(SerialExecutor.java:300)
    at org.eclipse.californium.core.network.CoapEndpoint$6.run(CoapEndpoint.java:1363)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
    at java.base/java.lang.Thread.run(Thread.java:840)
Caused by: org.eclipse.leshan.core.node.codec.CodecException: Invalid content [3c2f34323e3b72743d226f6d612e6c776d326d222c3c2f34322f32363235322f34333930372f31373431352f31313938313e3b45586c6b4d3d523b7953534c3d7271746d] for type CORELINK for path /3442/0/180
    at org.eclipse.leshan.core.node.codec.tlv.LwM2mNodeTlvDecoder.parseTlvValue(LwM2mNodeTlvDecoder.java:314)
    at org.eclipse.leshan.core.node.codec.tlv.LwM2mNodeTlvDecoder.parseResourceTlv(LwM2mNodeTlvDecoder.java:250)
    at org.eclipse.leshan.core.node.codec.tlv.LwM2mNodeTlvDecoder.parseObjectInstanceTlv(LwM2mNodeTlvDecoder.java:216)
    at org.eclipse.leshan.core.node.codec.tlv.LwM2mNodeTlvDecoder.parseTlv(LwM2mNodeTlvDecoder.java:151)
    at org.eclipse.leshan.core.node.codec.tlv.LwM2mNodeTlvDecoder.decode(LwM2mNodeTlvDecoder.java:76)
    at org.eclipse.leshan.core.node.codec.DefaultLwM2mDecoder.decodeTimestampedData(DefaultLwM2mDecoder.java:206)
    at org.eclipse.leshan.transport.californium.server.endpoint.ServerCoapMessageTranslator.createObserveResponse(ServerCoapMessageTranslator.java:108)
    ... 27 common frames omitted
Caused by: org.eclipse.leshan.core.link.LinkParseException: Unable to parse link </42>;rt=[oma.lwm2m] in </42>;rt="oma.lwm2m",</42/26252/43907/17415/11981>;EXlkM=R;ySSL=rqtm 
    at org.eclipse.leshan.core.link.lwm2m.DefaultLwM2mLinkParser.parseCoreLinkFormat(DefaultLwM2mLinkParser.java:138)
    at org.eclipse.leshan.core.node.codec.tlv.LwM2mNodeTlvDecoder.parseTlvValue(LwM2mNodeTlvDecoder.java:309)
    ... 33 common frames omitted
Caused by: org.eclipse.leshan.core.node.InvalidLwM2mPathException: Unable to parse LWM2M path prefix [/42] : Unexpected charaters '/' after ''
    at org.eclipse.leshan.core.node.PrefixedLwM2mPathParser$2.raiseException(PrefixedLwM2mPathParser.java:65)
    at org.eclipse.leshan.core.parser.StringParser.raiseException(StringParser.java:426)
    at org.eclipse.leshan.core.parser.StringParser.raiseException(StringParser.java:416)
    at org.eclipse.leshan.core.node.PrefixedLwM2mPathParser.parsePrefix(PrefixedLwM2mPathParser.java:72)
    at org.eclipse.leshan.core.link.lwm2m.DefaultLwM2mLinkParser.parseCoreLinkFormat(DefaultLwM2mLinkParser.java:134)

[sbernard31]

This was not a bug in parser but a bug in LwM2mTestObject which generated full numeric lwm2m path prefix.
And currently we decide that :

// the spec says : link (talking about alternate path) MUST NOT contain numerical URI segment.
// https://www.openmobilealliance.org/release/LightweightM2M/V1_2_1-20221209-A/HTML-Version/OMA-TS-LightweightM2M_Transport-V1_2_1-20221209-A.html#6-4-1-0-641-Alternate-Path
// We suppose this is true for all prefixed segment.

leshan/leshan-lwm2m-core/src/main/java/org/eclipse/leshan/core/node/PrefixedLwM2mPathParser.java

Lines 145 to 149 in 32b044b

	// the spec says : link (talking about alternate path) MUST NOT contain numerical URI segment.
	// https://www.openmobilealliance.org/release/LightweightM2M/V1_2_1-20221209-A/HTML-Version/OMA-TS-LightweightM2M_Transport-V1_2_1-20221209-A.html#6-4-1-0-641-Alternate-Path
	// We suppose this is true for all prefixed segment.

[sbernard31]

Fixed by : #1749