NdisSendNetBufferLists function (ndis.h)

Article
04/18/2022

Protocol drivers call the NdisSendNetBufferLists function to send network data that is contained in a list of NET_BUFFER_LIST structures.

Syntax

void NdisSendNetBufferLists(
  [in] NDIS_HANDLE                       NdisBindingHandle,
  [in] __drv_aliasesMem PNET_BUFFER_LIST NetBufferLists,
  [in] NDIS_PORT_NUMBER                  PortNumber,
  [in] ULONG                             SendFlags
);

Parameters

[in] NdisBindingHandle

A handle that identifies the target adapter. A previous call to NdisOpenAdapterEx returned this handle.

[in] NetBufferLists

A pointer to a linked list of NET_BUFFER_LIST structures. Each NET_BUFFER_LIST structure describes a list of NET_BUFFER structures.

[in] PortNumber

A port number that identifies a miniport adapter port. The default port number of a miniport adapter is zero. Protocol drivers that do not use miniport adapter ports should specify the default port.

[in] SendFlags

Flags that define attributes for the send operation. The flags can be combined with an OR operation. To clear all the flags, set this member to zero. This function supports the following flags:

NDIS_SEND_FLAGS_DISPATCH_LEVEL

Specifies that the current IRQL is DISPATCH_LEVEL. For more information about this flag, see Dispatch IRQL Tracking.

NDIS_SEND_FLAGS_CHECK_FOR_LOOPBACK

Specifies that NDIS should check for loopback. By default, NDIS does not loop back data to the driver that submitted the send request. An overlying driver can override this behavior by setting this flag. When this flag is set, NDIS identifies all the NET_BUFFER structures that contain data that matches the receive criteria for the binding. NDIS indicates NET_BUFFER structures that match the criteria to the overlying driver. This flag has no effect on checking for loopback, or looping back, on other bindings.

Return value

None

Remarks

After a protocol driver calls NdisSendNetBufferLists, NDIS submits the NET_BUFFER_LIST structures to an underlying driver's MiniportSendNetBufferLists function.

The protocol driver must allocate each NET_BUFFER_LIST structure from a pool by calling one of the following functions:

The protocol driver can preallocate NET_BUFFER_LIST structures--for example, in its DriverEntry routine. Alternatively, the driver, can allocate the structures just prior to calling NdisSendNetBufferLists and then free them when the send operation is complete. When NDIS returns a NET_BUFFER_LIST structure to ProtocolSendNetBufferListsComplete, the miniport driver can prepare the NET_BUFFER_LIST structure and any associated resources for reuse. Reusing the NET_BUFFER_LIST structures can yield better performance than returning the structures to a pool and then reallocating them for another send operation.

A protocol driver must set the SourceHandle member of each NET_BUFFER_LIST structure to the same value that it passes to the NdisBindingHandle parameter. The binding handle provides the information that NDIS requires to return the NET_BUFFER_LIST structure to the protocol driver after the underlying miniport driver calls NdisMSendNetBufferListsComplete.

Before calling NdisSendNetBufferLists, a protocol driver can set information that accompanies the send request with the NET_BUFFER_LIST_INFO macro . The underlying driver can retrieve this information with the NET_BUFFER_LIST_INFO macro.

Before a protocol driver calls NdisSendNetBufferLists with a list of NET_BUFFER_LIST structures, the protocol driver must ensure that the NET_BUFFER_LIST structures are set up in the order that the network data should be sent over the wire.

As soon as a protocol driver calls NdisSendNetBufferLists, it relinquishes ownership of the NET_BUFFER_LIST structures and all associated resources. NDIS calls the ProtocolSendNetBufferListsComplete function to return the structures and data to the protocol driver. NDIS can collect the structures and data from multiple send requests into a single linked list of NET_BUFFER_LIST structures before it passes the list to ProtocolSendNetBufferListsComplete.

Until NDIS calls ProtocolSendNetBufferListsComplete, the current status of a protocol-driver-initiated send is not available to the protocol driver. A protocol driver temporarily releases ownership of all resources that it allocated for a send request when it calls NdisSendNetBufferLists. A protocol driver should never attempt to examine the NET_BUFFER_LIST structures or any associated data after calling NdisSendNetBufferLists.

Requirements

Requirement	Value
Minimum supported client	Supported in NDIS 6.0 and later.
Target Platform	Universal
Header	ndis.h (include Ndis.h)
Library	Ndis.lib
IRQL	<=DISPATCH_LEVEL
DDI compliance rules	Irql_SendRcv_Function(ndis)