MiniportQueryInformation

MiniportQueryInformation is a required function that returns information about the capabilities and status of the driver and/or its network adapter.

NDIS_STATUS 
MiniportQueryInformation(
IN NDIS_HANDLE MiniportAdapterContext,
IN NDIS_OID Oid,
IN PVOID InformationBuffer,
IN ULONG InformationBufferLength,
OUT PULONG BytesWritten,
OUT PULONG BytesNeeded)

Parameters

• MiniportAdapterContext
  Specifies the handle to a miniport-allocated context area in which the driver maintains per-network adapter state, set up by MiniportInitialize.
• Oid
  Specifies the system-defined OID_XXX code designating the global query operation the driver should carry out.
• InformationBuffer
  Points to a buffer in which MiniportQueryInformation should return the OID-specific information.
• InformationBufferLength
  Specifies the number of bytes at InformationBuffer.
• BytesWritten
  Points to a variable that MiniportQueryInformation sets to the number of bytes it is returning at InformationBuffer.
• BytesNeeded
  Points to a variable that MiniportQueryInformation sets to the number of additional bytes it needs to satisfy the request if InformationBufferLength is less than Oid requires.

Return Values

MiniportQueryInformation can return one of the following:

• NDIS_STATUS_SUCCESS
  MiniportQueryInformation returned the requested information at InformationBuffer and set the variable at BytesWritten to the amount of information it returned.
• NDIS_STATUS_PENDING
  The driver will complete the request asynchronously with a call to NdisMQueryInformationComplete when it has gathered the requested information.
• NDIS_STATUS_INVALID_OID
  MiniportQueryInformation does not recognize the Oid.
• NDIS_STATUS_INVALID_LENGTH
  The InformationBufferLength does not match the length required by the given Oid. MiniportQueryInformation returned how many bytes the buffer should be at BytesNeeded.
• NDIS_STATUS_NOT_ACCEPTED
  MiniportQueryInformation attempted to gather the requested information from the network adapter but was unsuccessful.
• NDIS_STATUS_NOT_SUPPORTED
  MiniportQueryInformation does not support the Oid, which is optional.
• NDIS_STATUS_RESOURCES
  MiniportQueryInformation could not allocate sufficient resources to return the requested information. This return value does not necessarily mean that the same request, submitted at a later time, will be failed for the same reason.

Comments

NDIS calls the MiniportQueryInformation function either on its own behalf, such as to determine which options the driver supports or to manage binding-specific information for the miniport, or when a bound protocol driver calls NdisRequest.

NDIS makes one or more calls to MiniportQueryInformation just after a driver's MiniportInitialize function returns NDIS_STATUS_SUCCESS. NDIS supplies the following OIDs in its initialization-time calls to the driver's MiniportQueryInformation function:

• OID_GEN_MAXIMUM_LOOKAHEAD
  MiniportQueryInformation must return how many bytes of lookahead data the network adapter can provide, that is, the initial transfer capacity of the network adapter.

  Even if a driver supports multipacket receives and, therefore, will indicate an array of pointers to fully set up packets, MiniportQueryInformation must supply this information. Such a driver should return the maximum packet size it can indicate.

• OID_GEN_MAC_OPTIONS
  MiniportQueryInformation must return a bitmask set with the appropriate NDIS_MAC_OPTION_XXX flags indicating which options it (or its network adapter) supports, or it can return zero at InformationBuffer if the driver supports none of the options designated by these flags.

  For example, a network adapter driver always sets the NDIS_MAC_OPTION_NO_LOOPBACK flag if its network adapter has no internal hardware support for loopback. This tells NDIS to manage loopback for the driver, which cannot provide software loopback code as efficient as the NDIS library's because NDIS manages all binding-specific information for miniports. Any miniport that tries to provide software loopback must check the destination address of every send packet against the currently set filter addresses to determine whether to loop back each packet. WAN network adapter drivers must set this flag.

  Windows CE does not support full duplex. The following information is provided if driver portability is a concern.

Depending on the NdisMediumXXX that MiniportInitialize selected, NDIS submits additional intialization-time requests to MiniportQueryInformation, such as the following:

• OID_XXX_CURRENT_ADDRESS
  If the driver's MiniportInitialize function selected an NdisMediumXXX for which the system supplies a filter, NDIS calls MiniportQueryInformation to return the network adapter's current address in medium-specific format.
• OID_802_3_MAXIMUM_LIST_SIZE
  For Ethernet drivers, NDIS requests the multicast list size.

If possible, MiniportQueryInformation should not return NDIS_STATUS_PENDING for initialization-time requests. Until NDIS has sufficient information to set up bindings to the miniport, such requests should be handled synchronously.

Subsequently, the NDIS library intercepts all protocol-initiated queries on certain OIDs, such as the following:

OID_GEN_CURRENT_PACKET_FILTER
OID_GEN_PROTOCOL_OPTIONS
OID_802_5_CURRENT_FUNCTIONAL
OID_802_3_MULTICAST_LIST
OID_FDDI_LONG_MULTICAST_LIST (not supported for Windows CE)
OID_FDDI_SHORT_MULTICAST_LIST (not supported for Windows CE)

If MiniportQueryInformation does not complete a request synchronously and returns NDIS_STATUS_PENDING, the driver must complete the request later with a call to NdisMQueryInformationComplete. Until it completes any such request, the miniport can safely access the memory at InformationBuffer, BytesWritten, and BytesNeeded. After the miniport completes any query, ownership of these variables and the buffer reverts to NDIS or the caller of NdisRequest, whichever allocated the memory.

After a call to MiniportQueryInformation, NDIS submits no other requests to the driver until it has completed the current request, either synchronously or asynchronously. Instead, NDIS holds requests queued until the current query is completed.

MiniportQueryInformation can be pre-empted by an interrupt.

Requirements

Note   This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.

See Also

MiniportInitialize, NdisMQueryInformationComplete, NdisRequest

 Last updated on Tuesday, July 13, 2004

© 1992-2000 Microsoft Corporation. All rights reserved.