RxFsdDispatch function (mrx.h)

RxFsdDispatch implements the file system driver (FSD) dispatch for RDBSS to process an I/O request packet (IRP). A pointer to this routine is copied over the device driver dispatch table for the network mini-redirector driver by the RxDriverEntry routine when RDBSS is initialized.


NTSTATUS RxFsdDispatch(
  [in] IN PRDBSS_DEVICE_OBJECT RxDeviceObject,
  [in] IN PIRP                 Irp


[in] RxDeviceObject

A pointer to the RDBSS device object for this network mini-redirector.

[in] Irp

A pointer to the I/O request packet being processed.

Return value

RxFsdDispatch returns one of the following values:

Return code Description
A request was made on an invalid device object. For example, this error is returned if a file system object is passed as the RxDeviceObject parameter. This status value indicates failure.
An invalid request was made to create a named pipe or a mailslot (the MajorFunction member of the Irp was IRP_MJ_CREATE_MAILSLOT or IRP_MJ_CREATE_NAMED_PIPE). This status value indicates failure.
An asynchronous request was made and the status of the request is pending.
The RxFsdDispatch routine call was successful.


RxFsdDispatch is called by RDBSS to process an I/O request packet (IRP). These IRPs are normally received by RDBSS in response to a user-mode application requesting operations on a file. It is also possible for another kernel driver to issue such an IRP.

A pointer to RxFsdDispatch routine is copied over the driver dispatch table for a network mini-redirector driver when the RxDriverEntry routine is called to initialize RDBSS.

Internally, RDBSS maintains two dispatch vectors:

  • A common dispatch vector for most operations.
  • A private dispatch vector for file device FCB operations.
If the IRP is an IRP_MJ_CREATE request, then RxFsdDispatch will use a common dispatch vector. If the IRP is for an operation on an FCB of a file object, RxFsdDispatch will check if a private dispatch vector should be used. Otherwise a common dispatch vector will be used to process the IRP.

RxFsdDispatch calls internal routines to process the standard IRPs most of which result in a call to one of the callback routines implemented by the network mini-redirector driver.

A few IRPs are treated as special and handled internally by RDBSS. For example, the IRP_MJ_SYSTEM_CONTROL is used internally if WMI is enabled. IRP_MJ_CREATE_MAILSLOT or IRP_MJ_CREATE_NAMED_PIPE requests are treated specially and rejected (a STATUS_OBJECT_NAME_INVALID error is returned).


Target Platform Desktop
Header mrx.h (include Mrx.h, Rxstruc.h, Struchdr.h)

See also