Configuring Optional Filter Driver Services
NDIS calls a filter driver's FilterSetOptions function to configure optional filter driver services. NDIS calls FilterSetOptions within the context of the filter driver's call to the NdisFRegisterFilterDriver function
FilterSetOptions registers the default entry points for optional FilterXxx functions that are required for optional services, and can allocate other driver resources. To register optional services, the filter driver calls the NdisSetOptionalHandlers function and passes a characteristics structure at the OptionalHandlers parameter.
There are no optional filter driver services in the current Windows version.
Filter drivers can also call NdisSetOptionalHandlers to set the some FilterXxx function entry points for a given filter module. For more information, see Data Bypass Mode.
If the filter driver calls NdisSetOptionalHandlers from FilterRestart, the configuration changes only affect the filter module that NDIS is restarting. The configuration of other filter modules is not affected.