NdisAllocateBuffer

NdisAllocateBuffer creates a buffer descriptor mapping a specified virtual (sub)range within an already allocated, nonpaged memory block.

VOID
  NdisAllocateBuffer(
    OUT PNDIS_STATUS  Status,
    OUT PNDIS_BUFFER  *Buffer,
    IN NDIS_HANDLE  PoolHandle,
    IN PVOID  VirtualAddress,
    IN UINT  Length
    );

Parameters

Status

Pointer to a caller-supplied variable in which this function returns the final status of the buffer allocation, which is NDIS_STATUS_SUCCESS if it returned a valid buffer descriptor pointer at Buffer and otherwise NDIS_STATUS_FAILURE.

Buffer

Pointer to a caller-supplied variable in which this function returns a pointer to the allocated buffer descriptor.

PoolHandle

Specifies the handle returned by a preceding call to NdisAllocateBufferPool.

VirtualAddress

Pointer to the base virtual address of previously allocated system-space memory to be mapped in the returned buffer descriptor.

Length

Specifies the number of bytes to be mapped.

Headers

Declared in Ndis.h. Include Ndis.h.

Comments

NdisAllocateBuffer allocates storage for and initializes a buffer descriptor to map a specified range of previously allocated memory, such as memory used for a packet header or a NIC receive buffer.

Buffer descriptor allocation draws on the buffer pool that NdisAllocateBufferPool creates. A driver can call NdisAllocateBuffer as many times as necessary to allocate the buffer descriptors that it requires if it called NdisAllocateBufferPool during initialization.

All lower-level NDIS drivers must allocate all buffer descriptors that they chain to packets from buffer pool. Only highest-level protocol drivers can be given OS-dependent descriptors mapping virtual memory ranges, and, if these memory descriptors are equivalent to NDIS buffer descriptors, a highest-level protocol can pass such descriptors as parameters to NdisXxx functions.

Callers of NdisAllocateBuffer run at IRQL <= DISPATCH_LEVEL.

See Also

NdisAllocateBufferPool, NdisAllocateMemoryWithTag, NdisFreeBuffer