继续问几个关于passthru的问题

下面这段代码节选自passthru中
NDIS_STATUS
PtReceive(
IN  NDIS_HANDLE ProtocolBindingContext,
IN  NDIS_HANDLE MacReceiveContext,
IN  PVOID HeaderBuffer,
IN  UINT HeaderBufferSize,
IN  PVOID LookAheadBuffer,
IN  UINT LookAheadBufferSize,
IN  UINT PacketSize
)
/*++

Routine Description:
LBFO - need to use primary for all receives

Arguments:


Return Value:

--*/
{
PADAPT pAdapt =(PADAPT)ProtocolBindingContext;
PNDIS_PACKET MyPacket, Packet;
NDIS_STATUS Status = NDIS_STATUS_SUCCESS;

if(!pAdapt->MiniportHandle)
{
Status = NDIS_STATUS_FAILURE;
}
else do
{
//
// We should not be getting Receives on a Secondary, this is just specific to our  LBFO driver
//

if(pAdapt->isSecondary)
{
DBGPRINT(\"PASSTHRU GETTING RECIEVES ON SECONDARY\\n\");
ASSERT(0);
}

//
// If this was indicated by the miniport below as a packet, then get that packet pointer and indicate
// it as a packet as well(with appropriate status). This way the OOB stuff is accessible to the
// transport above us.
//
Packet = NdisGetReceivedPacket(pAdapt->BindingHandle, MacReceiveContext);
if(Packet != NULL)
{
//
// Get a packet off the pool and indicate that up
//
NdisDprAllocatePacket(&Status,
 &MyPacket,
 pAdapt->RecvPacketPoolHandle);

if(Status == NDIS_STATUS_SUCCESS)
{
 MyPacket->Private.Head = Packet->Private.Head;
 MyPacket->Private.Tail = Packet->Private.Tail;

 //
 // Get the original packet(it could be the same packet as one received or a different one
 // based on # of layered MPs) and set it on the indicated packet so the OOB stuff is

visible
 // correctly at the top.
 //
 NDIS_SET_ORIGINAL_PACKET(MyPacket, NDIS_GET_ORIGINAL_PACKET(Packet));
 NDIS_SET_PACKET_HEADER_SIZE(MyPacket, HeaderBufferSize);

 //
 // Set Packet Flags
 //
 NdisGetPacketFlags(MyPacket) = NdisGetPacketFlags(Packet);

 //
 // Make sure the status is set to NDIS_STATUS_RESOURCES.
 //
 NDIS_SET_PACKET_STATUS(MyPacket, NDIS_STATUS_RESOURCES);

 NdisMIndicateReceivePacket(pAdapt->MiniportHandle, &MyPacket, 1);

 ASSERT(NDIS_GET_PACKET_STATUS(MyPacket) == NDIS_STATUS_RESOURCES);  //这句话是什么意思，为

什么要判断这个属性，难道上层驱动会修改这个熟悉
 NdisDprFreePacket(MyPacket);
 break;
}
}

//
// Fall through if the miniport below us has either not indicated a packet or we could not
// allocate one
//
pAdapt->IndicateRcvComplete = TRUE; //有什么用
switch(pAdapt->Medium)
{
 case NdisMedium802_3:
NdisMEthIndicateReceive(pAdapt->MiniportHandle,
MacReceiveContext,
HeaderBuffer,
HeaderBufferSize,
LookAheadBuffer,
LookAheadBufferSize,
PacketSize);
break;

 case NdisMedium802_5:
NdisMTrIndicateReceive(pAdapt->MiniportHandle,
MacReceiveContext,
HeaderBuffer,
HeaderBufferSize,
LookAheadBuffer,
LookAheadBufferSize,
PacketSize);
break;

 case NdisMediumFddi:
NdisMFddiIndicateReceive(pAdapt->MiniportHandle,
 MacReceiveContext,
 HeaderBuffer,
 HeaderBufferSize,
 LookAheadBuffer,
 LookAheadBufferSize,
 PacketSize);
break;

 default:
ASSERT(0);
break;
}

} while(FALSE);

return Status;
}

我又几个问题比较困惑:
在这个函数中，在向上提交Packet时，他直接用NdisMxxxxIndicateReceive函数提交上去。
但是我看DDK中的介绍，提交Packet时候，必须自己创建包描述符，内存等等。但是在这个事例函数中怎么直接就提交上去。

2。在这个函数中他怎么没有判断lookaheadbuffersize和packetsize
的大小，按照ddk中就解释，先判断其大小，然后决定是否调用NdisTransferData啊。他好像没有这么做，是不是违背DDK中的做法。

3 还是在这个函数中， pAdapt->IndicateRecvComplete=true;这句话得意图何在。
还有在判断OOB中，一开始设置Packet的NDIS_STATUS_RESOURCE属性，在Indicate 过后，又判断这个属性，难道上层在接受这个Packet时属性

值会变。
请高手不惜赐教。谢谢拉！



[编辑 -  10/31/03 by  jasic2002]

[编辑 -  11/1/03 by  jasic2002]