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What is the purpose of filterId?

klimandrklimandr Member Posts: 8

What is the purpose of filterId?
Each filter has GUID, it uniquelly identifies filter, but each filter has filterId yet. In what cases I can use filterId, and what operations I can do using filterId?

Comments

  • Tim_RobertsTim_Roberts Member - All Emails Posts: 13,068
    via Email
    klimandr wrote:
    > What is the purpose of filterId?
    >
    > Each filter has GUID, it uniquelly identifies filter, but each filter has filterId yet. In what cases I can use filterId, and what operations I can do using filterId?

    What kind of a driver are you talking about?  The word "filter" is
    aggressively overloaded in the Windows world.

    Tim Roberts, [email protected]
    Providenza & Boekelheide, Inc.

  • Peter_Viscarola_(OSR)Peter_Viscarola_(OSR) Administrator Posts: 7,413

    No idea what you mean here. I am not aware of anything named "filterId".

    More detail would be useful,

    Peter

    Peter Viscarola
    OSR
    @OSRDrivers

  • Don_BurnDon_Burn Member - All Emails Posts: 1,653
    via Email
    If you are referring to the filterID in a WFP driver, then filterID can be thought of as a handle for the filter instance. Yes there is a GUID, but that is not for a specific instance, and it is a pain to lookup and compare GUID's so for performance a 64-bit ID makes a lot of sense.


    Don Burn
    Windows Driver Consulting
    Website: http://www.windrvr.com
  • klimandrklimandr Member Posts: 8

    @Peter_Viscarola_(OSR) said:
    No idea what you mean here. I am not aware of anything named "filterId".

    More detail would be useful,

    Peter

    @Tim_Roberts said:
    What kind of a driver are you talking about?  The word "filter" is
    aggressively overloaded in the Windows world.

    I am refer to filterID in WFP drivers. I did not thought that it is more than one instances named "filter" in windows.
    Each filter structure FWPM_FILTER0_ has member filterKey of type GUID and member filterId of type UINT64. We can uniquely identify filter with GUID and with filterId. And in what cases I can use filterId, and what operations I can do using filterId?

  • klimandrklimandr Member Posts: 8

    Thank you, @Don_Burn.

    @Don_Burn said
    ...Yes there is a GUID, but that is not for a specific instance..

    I don't understand that. Why GUID is not for a specific instance? All instances in wfp has each own GUID.

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