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Building and sending a Bluetooth request block (BRB)

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The following procedure outlines the general process that a profile driver follows to build and send a Bluetooth request block (BRB). A BRB is a block of data that describes the Bluetooth operation to perform.

To build and send a BRB

  1. Allocate an IRP. For more information about how to use IRPs, see Handling IRPs.
  2. Allocate a BRB. To allocate BRBs, call the BthAllocateBrb function that the Bluetooth driver stack exports for use by profile drivers. To obtain a pointer to the BthAllocateBrb function, see Querying for Bluetooth Interfaces.
  3. Initialize the parameters of the BRB. Each BRB uses a corresponding structure. Set the members of the structure according to the intended use. For a list of BRBs and their corresponding structures see Using the Bluetooth Driver Stack.
  4. Initialize the parameters of the IRP. Set the MajorFunction member of the IRP to IRP_MJ_INTERNAL_DEVICE_CONTROL. Set the Parameters.DeviceIoControl.IoControlCode member to IOCTL_INTERNAL_BTH_SUBMIT_BRB. Set the Parameters.Others.Argument1 member to point to the BRB.
  5. Pass the IRP down the driver stack. Call IoCallDriver to send the IRP to the next-lower driver.

The following pseudocode example demonstrates how to set up a L2CAP Ping BRB for the Bluetooth driver stack to process. For readability, the example does not demonstrate error handling.

#include <bthddi.h>

// Code for obtaining the BthInterface pointer

// Define a custom pool tag to identify your profile driver's dynamic memory allocations.
// You should change this tag to easily identify your driver's allocations from other drivers.
#define PROFILE_DRIVER_POOL_TAG '_htB'

PIRP Irp;
Irp = IoAllocateIrp( DeviceExtension->ParentDeviceObject->StackSize, FALSE );

PBRB_L2CA_PING BrbPing; // Define storage for a L2CAP Ping BRB

// Allocate the Ping BRB
BrbPing = BthInterface->BthAllocateBrb( BRB_L2CA_PING, PROFILE_DRIVER_POOL_TAG );

// Set up the next IRP stack location
PIO_STACK_LOCATION NextIrpStack;
NextIrpStack = IoGetNextIrpStackLocation( Irp );
NextIrpStack->MajorFunction = IRP_MJ_INTERNAL_DEVICE_CONTROL;
NextIrpStack->Parameters.DeviceIoControl.IoControlCode = IOCTL_INTERNAL_BTH_SUBMIT_BRB;
NextIrpStack->Parameters.Others.Argument1 = BrbPing;

// Pass the IRP down the driver stack
NTSTATUS Status;
Status = IoCallDriver( DeviceExtension->NextLowerDriver, Irp );