//

// NDIS_PACKET结构的定义

//

typedef struct _NDIS_PACKET

{

NDIS_PACKET_PRIVATE Private;

//这个其实是一个链表结构,Private.Head指向第一个链表,Private.Tail指向最后一个

//以下有关于这个结构的解释  

union

{

struct // For Connection-less miniports

{

UCHAR MiniportReserved[*sizeof(PVOID)];

UCHAR WrapperReserved[*sizeof(PVOID)];

};  

struct

{

//

// For de-serialized miniports. And by implication conn-oriented miniports.

// This is for the send-path only. Packets indicated will use WrapperReserved

// instead of WrapperReservedEx

//

UCHAR MiniportReservedEx[*sizeof(PVOID)];

UCHAR WrapperReservedEx[sizeof(PVOID)];

};  

struct

{

UCHAR MacReserved[*sizeof(PVOID)];

};

};  

ULONG_PTR Reserved[]; // For compatibility with Win

UCHAR ProtocolReserved[];  

} NDIS_PACKET, *PNDIS_PACKET, **PPNDIS_PACKET;  

// NDIS_PACKET_PRIVATE 的定义

typedef struct _NDIS_PACKET_PRIVATE

{

UINT PhysicalCount; // number of physical pages in packet.

UINT TotalLength; // Total amount of data in the packet.

PNDIS_BUFFER Head; // 链表指针,指向第一个

PNDIS_BUFFER Tail; // 链表指针,指向最后一个  

// if Head is NULL the chain is empty; Tail doesn\'t have to be NULL also   

PNDIS_PACKET_POOL Pool; // so we know where to free it back to

UINT Count;

ULONG Flags;

BOOLEAN ValidCounts;

UCHAR NdisPacketFlags; // See fPACKET_xxx bits below

USHORT NdisPacketOobOffset;

} NDIS_PACKET_PRIVATE, * PNDIS_PACKET_PRIVATE;  

//NDIS_BUFFER定义 其实就是一个内存描述符

typedef struct _NDIS_BUFFER {

struct _NDIS_BUFFER *Next; //指向下一个节点的指针

PVOID VirtualAddress;      //指向报文首地址

PNDIS_BUFFER_POOL Pool;

UINT Length;               //报文数据长度

UINT Signature;

} NDIS_BUFFER, * PNDIS_BUFFER;  

NDIS_STATUS status ;

    PNDIS_BUFFER NdisBuffer ;

    UINT TotalPacketLength =, copysize =, DataOffset =, PhysicalBufferCount  ,  BufferCount   ;

    PUCHAR mybuffer = NULL ,tembuffer = NULL ;  

//假设这个是在PtReceive等函数中得到的PACKET

NdisQueryPacket(packet                     //我们先得到第一个NDISBUFFER 的指针

        , &PhysicalBufferCount

        , &BufferCount

        ,&NdisBuffer                               //NdisBuffer就是指向链表头

        , &TotalPacketLength

        );

/*

其实也可以不用那么麻烦 直接  NdisBuffer = packet->Private.Head ;就可以取得第一个BUFFER了

*/

    status = NdisAllocateMemory( &mybuffer, , , HighestAcceptableMax );  //分配我们自己的内存块

    if( status != NDIS_STATUS_SUCCESS )

        return NDIS_STATUS_FAILURE ;

    NdisZeroMemory( mybuffer,) ;

    NdisQueryBufferSafe(  //取得NDIS_BUFFER描述符中数据的首地址和大小

                                NdisBuffer,

                                &tembuffer,

                                ©size,

                                NormalPagePriority

    );  

        //将数据复制到我们的内存中

    NdisMoveMemory(mybuffer, tembuffer, copysize) ;

    DataOffset = copysize ;

    while()

    {

        /*

                也可以这样操作而不用NdisGetNextBuffer

        if(NdisBuffer->Next == packet->Private.Tail )

            break ;

        NdisBuffer = NdisBuffer->Next ;

        if(pmdl == NULL )

           break ;

           */

        //获得下一个NDIS_BUFFER的的指针

    NdisGetNextBuffer(NdisBuffer , &NdisBuffer ) ;

        如果指针是NULL  那么表示到链表尾了

    if( NdisBuffer == NULL )

        break ;

    NdisQueryBufferSafe(

                                NdisBuffer,

                                &tembuffer,

                                ©size,

                                NormalPagePriority

                                ) ;

    NdisMoveMemory( mybuffer + DataOffset , tembuffer, copysize) ;

    DataOffset += copysize  ;

    }

//OK  我们要的数据就全部都在我们申请的内存mybuffer 数据大小为DataOffset