驱动开发之五 --- TDI之六【译文】

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转自http://hi.baidu.com/combojiang/blog/item/835622dcef3123a4cd1166c6.html

同样的使用TDI_RECEIVE来完成数据接收。然而我们却没有用它来实现。实际上，如果你注意到，你可以创建回调来通知你数据或者其他事件什么时候到达。这就是我们所做的。我实现了一个API包装函数来创建任意的事件句柄。如下：

NTSTATUS TdiFuncs_SetEventHandler(PFILE_OBJECT pfoTdiFileObject,

LONG InEventType, PVOID InEventHandler, PVOID InEventContext)

{

NTSTATUS NtStatus = STATUS_INSUFFICIENT_RESOURCES;

PIRP pIrp;

IO_STATUS_BLOCK IoStatusBlock = {0};

PDEVICE_OBJECT pTdiDevice;

LARGE_INTEGER TimeOut = {0};

UINT NumberOfSeconds = 60*3;

TDI_COMPLETION_CONTEXT TdiCompletionContext;

KeInitializeEvent(&TdiCompletionContext.kCompleteEvent,

NotificationEvent, FALSE);

* The TDI Device Object is required to send these

* requests to the TDI Driver.

pTdiDevice = IoGetRelatedDeviceObject(pfoTdiFileObject);

* Step 1: Build the IRP. TDI defines several macros and functions

* that can quickly create IRP's, etc. for variuos purposes.

* While this can be done manually it's easiest to use the macros.

pIrp = TdiBuildInternalDeviceControlIrp(TDI_SET_EVENT_HANDLER,

pTdiDevice, pfoConnection, &TdiCompletionContext.kCompleteEvent,

&IoStatusBlock);

if(pIrp)

{

* Step 2: Set the IRP Parameters

TdiBuildSetEventHandler(pIrp, pTdiDevice, pfoTdiFileObject,

NULL, NULL, InEventType, InEventHandler, InEventContext);

NtStatus = IoCallDriver(pTdiDevice, pIrp);

* If the status returned is STATUS_PENDING this means that

* the IRP will not be completed synchronously and the driver has

* queued the IRP for later processing. This is fine but we do not

* want to return this thread, we are a synchronous call so we want

* to wait until it has completed. The EVENT that we provided

* will be set when the IRP completes.

if(NtStatus == STATUS_PENDING)

{

KeWaitForSingleObject(&TdiCompletionContext.kCompleteEvent,

Executive, KernelMode, FALSE, NULL);

* Find the Status of the completed IRP

NtStatus = IoStatusBlock.Status;

}

return NtStatus;

}

使用这个函数实现回调的代码如下：

Collapse

NtStatus = TdiFuncs_SetEventHandler(

pTdiExampleContext->TdiHandle.pfoTransport,

TDI_EVENT_RECEIVE,

TdiExample_ClientEventReceive,

(PVOID)pTdiExampleContext);

NTSTATUS TdiExample_ClientEventReceive(PVOID TdiEventContext,

CONNECTION_CONTEXT ConnectionContext,

ULONG ReceiveFlags,

ULONG BytesIndicated,

ULONG BytesAvailable,

ULONG *BytesTaken,

PVOID Tsdu,

PIRP *IoRequestPacket)

{

NTSTATUS NtStatus = STATUS_SUCCESS;

UINT uiDataRead = 0;

PTDI_EXAMPLE_CONTEXT pTdiExampleContext =

(PTDI_EXAMPLE_CONTEXT)TdiEventContext;

PIRP pIrp;

DbgPrint("TdiExample_ClientEventReceive 0x%0x, %i, %i\n",

ReceiveFlags, BytesIndicated, BytesAvailable);

*BytesTaken = BytesAvailable;

* This implementation is extremely simple. We do not queue

* data if we do not have an IRP to put it there. We also

* assume we always get the full data packet sent every recieve.

* These are Bells and Whistles that can easily be added to

* any implementation but would help to make the implementation

* more complex and harder to follow the underlying idea. Since

* those essentially are common-sense add ons they are ignored and

* the general implementation of how to Queue IRP's and

* recieve data are implemented.

pIrp = HandleIrp_RemoveNextIrp(pTdiExampleContext->pReadIrpListHead);

if(pIrp)

{

PIO_STACK_LOCATION pIoStackLocation =

IoGetCurrentIrpStackLocation(pIrp);

uiDataRead =

BytesAvailable > pIoStackLocation->Parameters.Read.Length ?

pIoStackLocation->Parameters.Read.Length : BytesAvailable;

pIrp->Tail.Overlay.DriverContext[0] = NULL;

RtlCopyMemory(pIrp->AssociatedIrp.SystemBuffer, Tsdu, uiDataRead);

pIrp->IoStatus.Status = NtStatus;

pIrp->IoStatus.Information = uiDataRead;

IoCompleteRequest(pIrp, IO_NETWORK_INCREMENT);

}

* The I/O Request can be used to recieve the rest of the data.

* We are not using it in this example however and will actually

* be assuming that we always get all the data.

*IoRequestPacket = NULL;

return NtStatus;

}

不要对HandleIrp_RemoveNextIrp产生恐惧，我们会在本篇后面部分讲怎样排队IRP请求。

posted on 2009-03-23 22:07 iniwf 阅读(452) 评论(0) 编辑收藏引用所属分类: 驱动

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