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I am trying to add a WFP filter while holding an NDIS RW lock, but FwpmEngineOpen or FwpmTransactionBegin functions fail. Is there a limitation that prevents these functions to work at Dispatch level?

Thanks!

winsor.wfp
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1 Answers1

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The documentation for FwpmEngineOpen0 states that the requirement is IRQL == PASSIVE_LEVEL, so it won't work in DISPATCH_LEVEL.

seva titov
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  • You are right. The MSDN documentation mentions this for FwpmEngineOpen0, but not for FwpmTransactionBegin0 or other WFP management functions. Although I have found [here](http://msdn.microsoft.com/en-us/library/windows/hardware/ff557104%28v=vs.85%29.aspx) that all of WFP management functions except FwpmFreeMemory0 must be running at IRQL = PASSIVE_LEVEL. Callers of FwpmFreeMemory0 must be running at IRQL <= DISPATCH_LEVEL. – winsor.wfp Jan 07 '15 at 14:30