Manpage of CD_UNITDATA_IND

CD_UNITDATA_IND

Section: Communications Device Interface (CDI) (7)
Updated: 2008-10-31
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NAME

CD_UNITDATA_IND - data receive indication

SYNOPSIS

This primitive consists of one M_PROTO(9) message block followed by one or more M_DATA(9) message blocks. The M_PROTO(9) message block is optional. The M_PROTO(9) message block is structured as follows:

typedef struct {
    cd_ulong cd_primitive;
    cd_ulong cd_state;
    cd_ulong cd_src_addr_length;
    cd_ulong cd_src_addr_offset;
    cd_ushort cd_addr_type;
    cd_ushort cd_priority;
    cd_ulong cd_dest_addr_length;
    cd_ulong cd_dest_addr_offset;
} cd_unitdata_ind_t;

DESCRIPTION

This provider originated primitives indicates that data has arrived for the specified source and destination addresses with the specified priority.

The M_PROTO(9) message block is only necessary when the parameters included in the primitive are not implied by the communications device.

Parameters

This primitive contains the following parameters:

cd_primitive

Indicates the primitives type.

cd_state

Indicates the state of the CD provider following the indication primitive. cd_state can be one fo the following values:

CD_UNATTACHED: No PPA attached.
CD_UNUSABLE: PPA cannot be used.
CD_DISABLED: PPA attached.
CD_ENABLE_PENDING: Waiting ack of enable req.
CD_ENABLED: Awaiting use.
CD_READ_ACTIVE: Input section enabled; disabled after data arrives.
CD_INPUT_ALLOWED: Input section permanently enabled.
CD_DISABLE_PENDING: Waiting ack of disable req.
CD_OUTPUT_ACTIVE: Output section active only.
CD_XRAY: Xray-ing another ppa.

cd_src_addr_length

Indicates the length of the source address associated with the recieved data. When sending endpoint uses the CDI, this address is the same as the cd_dest_addr_lenght of the corresponding CD_UNITDATA_REQ(7) primitive. When no source address is provided, or the source address is implicit to the data, this field is coded zero (0).

cd_src_addr_offset

Indicates the offset of the source address from the beginning of the M_PROTO(9) message block. When cd_src_addr_length is zero (0), this field is also zero (0).

cd_addr_type

CD_SPECIFIC: Indicates that an address is contained in the primitive. When cd_addr_type is set to CD_SPECIFIC, a destination address is indicated in the cd_dest_addr_length and cd_dest_addr_offset fields.
CD_BROADCAST: Indicates that the data was sent to the implicit broadcast address and no specific address follows. When cd_addr_type is set to CD_BROADCAST, the fields cd_dest_addr_length and cd_dest_addr_offset are coded zero (0) and should be ignored by the CD user.
CD_IMPLICIT: Indicates that an implicit address was used, or that the address is embedded in the data. When cd_addr_type is set to CD_IMPLICIT, the fields cd_dest_addr_length and cd_dest_addr_offset are coded zero (0) and should be ignored by the CD user.

cd_priority

Indicates the priority of the received data. The priority is provider- and device-specific.

cd_dest_addr_length

Indicates the length of the destination addres. When this field is coded zero (0), it indicates that no destination address is included in the message.

cd_dest_addr_offset

Indicates the offset of the destination address from the start of the M_PROTO(9) message block. When cd_dest_addr_length is zero (0), this field is also coded zero (0) and should be ignored by the CD user.

State

This primitive is valid in any state where the device is allowed to received ata (i.e. CD_READ_ACTIVE, and CD_INPUT_ALLOWED). The state remains unchanged.

FILES

HISTORY

The Communications Device Interface first appeared in SVR 4[1].

CONFORMANCE

This interface conforms to CDI with Gcom extensions.

REFERENCES

[1]: SVR 4, UNIX® System V Release 4 Programmer's Manual, 1990, (Englewood Cliffs, New Jersey), AT&T UNIX System Laboratories, Inc., Prentice Hall.
[2]: Magic Garden, The Magic Garden Explained: The Internals of UNIX® System V Release 4 / An Open Systems Design, 1994, (Australia), B. Goodheart, J. Cox, Prentice Hall. [ISBN 0-13-098138-9]
[3]: Advanced Programming in the UNIX®Environment, 15th edition, December 1997, (Reading, Massachusetts), W. R. Stevens, Addison Wesley. [ISBN 0-201-56317-7]