LLC_DIR_OPEN_DIRECT_PARMS Overview  Group

The LLC_DIR_OPEN_DIRECT_PARMS structure is the DLC parameter table for the LLC_DIR_OPEN_DIRECT command. You pass a pointer to this structure using the pParameterTable member of the CCB_PARMS union.

typedef struct {

    USHORT Reserved[4];

    USHORT usOpenOptions;

    USHORT usEthernetType;

    ULONG ulProtocolTypeMask;

    ULONG ulProtocolTypeMatch;

    USHORT usProtocolTypeOffset;

} LLC_DIR_OPEN_DIRECT_PARMS, *PLLC_DIR_OPEN_DIRECT_PARMS;

Members

Reserved

Reserved.

usOpenOptions

usEthernetType

Specifies an LLC_ETHERNET_TYPE value representing the type of Ethernet frame to receive. LLC_ETHERNET_TYPE is an enumerated type. The following values are defined.

Value	Meaning
LLC_ETHERNET_TYPE_DEFAULT	Use the parameter value set in the registry.
LLC_ETHERNET_TYPE_AUTO	Use automatic header type selection for links.
LLC_ETHERNET_TYPE_802_3	Always use 802.3 LAN headers.
LLC_ETHERNET_TYPE_DIX	Always use LLC on DIX SNA type.

ulProtocolTypeMask

Specifies a mask used in a bitwise AND operation with the data. The result must be equal to ulProtocolTypeMatch. Otherwise, set this parameter to zero.

ulProtocolTypeMatch

Ignored if ulProtocolTypeMask is zero.

usProtocolTypeOffset

Specifies the distance of the protocol type from the beginning of the protocol header (offset 14 in the frame header). Ignored if ulProtocolTypeMask is zero.

Remarks

After you have issued the LLC_RECEIVE command for the direct station, the application has ownership of the direct station and can receive frames .

Windows DLC differs from the IBM DLC specification in that you can receive frames of specific Ethernet types using the direct station when the usEthernetType member has a valid Ethernet type.

The ulProtoTypeMask, ulProtocolTypeMatch, and usProtocolTypeOffset members are optional. They specify the protocol type mask, match, and offset, respectively. They receive frames for a particular subprotocol type or socket. That is, the packet is received whenever the following statement is true:

(* (PULONG)((PUCHAR)pFrame + 14 + offset) & mask) == match

See Also

AcsLan, CCB_PARMS

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