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WFP: Associating a flowContext at ALE_CONNECT layer
I am writing a WFP driver to perform deep inspection at the Stream layer.
A context is associated at ALE_CONNECT (Connect layer) using FwpsFlowAssociateContext.
There is a specific need to associate a context in the Connect layer.
However for FlowEstablishedClassify or StreamClassify callouts, WFP passes the flowContext as 0.
Hence I am not able to dereference my context and perform the deep inspection at the stream layer.
Please let me know if there is anything I am missing here.
When the flow gets closed WFP calls AleConnectFlowDeleteFn() with the correct context which wad allocated during AleConnectClassify()
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Comments
What parameters are you passing to these functions, what are they returning?
thanks for your response, I saw this response just now.. The issue was that I was passing a wrong calloutID and layerID. It started working correctly after passing callout and streamID. I have another issue now - and this is when FwpsFlowRemoveContext returns STATUS_UNSUCCESSFUL (There is no context currently associated with the data flow.) for existing flows and hence the callout can't be unregistered.
there is a similar issue reported but with no reply from MS. https://social.msdn.microsoft.com/Forums/sqlserver/en-US/3d7e45ee-d3dd-49cf-8599-743cdac76097/fwpsflowremovecontext-returns-statusunsuccessful?forum=wfp
Just an update - the issue reported in the above URL when a context is associated at ALE_CONNECT layer is a definite MS WFP bug. The driver cannot be unloaded in this case, the code works perfectly well when the context is attached at FLOW_ESTABLISHED layer.