org.jscsi.parser.nop

Class NOPOutParser

java.lang.Object

org.jscsi.parser.AbstractMessageParser

org.jscsi.parser.InitiatorMessageParser

org.jscsi.parser.nop.NOPOutParser

public final class NOPOutParser
extends InitiatorMessageParser

NOPOutParser

This class parses a NOP-Out message defined in the iSCSI Standard (RFC3720).

A NOP-Out may be used by an initiator as a "ping request" to verify that a connection/session is still active and all its components are operational. The NOP-In response is the "ping echo".

A NOP-Out is also sent by an initiator in response to a NOP-In.

A NOP-Out may also be used to confirm a changed ExpStatSN if another PDU will not be available for a long time.

Upon receipt of a NOP-In with the Target Transfer Tag set to a valid value (not the reserved 0xffffffff), the initiator MUST respond with a NOP-Out. In this case, the NOP-Out Target Transfer Tag MUST contain a copy of the NOP-In Target Transfer Tag.

These fields have these specific meanings:

Initiator Task Tag:
The NOP-Out MUST have the Initiator Task Tag set to a valid value only if a response in the form of NOP-In is requested (i.e., the NOP-Out is used as a ping request). Otherwise, the Initiator Task Tag MUST be set to 0xffffffff.

When a target receives the NOP-Out with a valid Initiator Task Tag, it MUST respond with a Nop-In Response (see Section 10.19 NOP-In).

If the Initiator Task Tag contains 0xffffffff, the I bit MUST be set to 1 and the CmdSN is not advanced after this PDU is sent.

Ping Data
Ping data are reflected in the NOP-In Response. The length of the reflected data are limited to MaxRecvDataSegmentLength. The length of ping data are indicated by the DataSegmentLength. 0 is a valid value for the DataSegmentLength and indicates the absence of ping data.

Author:

Volker Wildi

Field Summary

Fields

Modifier and Type	Field and Description
protected int	targetTransferTag The TargetTransferTag.

Fields inherited from class org.jscsi.parser.InitiatorMessageParser

commandSequenceNumber, expectedStatusSequenceNumber

Fields inherited from class org.jscsi.parser.AbstractMessageParser

logicalUnitNumber, protocolDataUnit

Constructor Summary

Constructors

Constructor and Description
NOPOutParser(ProtocolDataUnit initProtocolDataUnit) Default constructor, creates a new, empty NOPOutParser object.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	checkIntegrity() This method checks, if all parsed fields are valid.
void	clear() This method sets all settings to their initial values.
protected void	deserializeBytes1to3(int line) Parse the bytes 1 till 3 in the Basic Header Segment.
protected void	deserializeBytes20to23(int line) Parse the bytes 20 till 23 in the Basic Header Segment.
DataSegmentFactory.DataSegmentFormat	getDataSegmentFormat() If this method returns true, hen it indicates that the data segment data is interpreted as binary data.
int	getTargetTransferTag() A target assigned identifier for the operation.
protected int	serializeBytes20to23() Serializes the bytes 20 till 23 in the Basic Header Segment.
String	toString() This method concatenate all the fields of a derived parser to allow an easy generation of debug informations.

Methods inherited from class org.jscsi.parser.InitiatorMessageParser

deserializeBytes24to27, deserializeBytes28to31, deserializeBytes32to35, deserializeBytes36to39, deserializeBytes40to43, deserializeBytes44to47, getCommandSequenceNumber, getExpectedStatusSequenceNumber, getShortInfo, incrementSequenceNumber, serializeBytes1to3, serializeBytes24to27, serializeBytes28to31, serializeBytes32to35, serializeBytes36to39, serializeBytes40to43, serializeBytes44to47, setCommandSequenceNumber, setExpectedStatusSequenceNumber

Methods inherited from class org.jscsi.parser.AbstractMessageParser

canContainAdditionalHeaderSegments, canHaveDigests, deserializeBytes12to15, deserializeBytes8to11, getLogicalUnitNumber, serializeBytes12to15, serializeBytes8to11, setLogicalUnitNumber

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

targetTransferTag

protected int targetTransferTag

The TargetTransferTag.

Constructor Detail

NOPOutParser

public NOPOutParser(ProtocolDataUnit initProtocolDataUnit)

Default constructor, creates a new, empty NOPOutParser object.

Parameters:

initProtocolDataUnit - The reference ProtocolDataUnit instance, which contains this NOPOutParser subclass object.

Method Detail

getTargetTransferTag

public final int getTargetTransferTag()

A target assigned identifier for the operation.

The NOP-Out MUST only have the Target Transfer Tag set if it is issued in response to a NOP-In with a valid Target Transfer Tag. In this case, it copies the Target Transfer Tag from the NOP-In PDU. Otherwise, the Target Transfer Tag MUST be set to 0xffffffff.

When the Target Transfer Tag is set to a value other than 0xffffffff, the LUN field MUST also be copied from the NOP-In.

Returns:

The target transfer tag of this object.

toString

public final String toString()

This method concatenate all the fields of a derived parser to allow an easy generation of debug informations.

Overrides:

toString in class InitiatorMessageParser

Returns:

The debug formatted string.

getDataSegmentFormat

public final DataSegmentFactory.DataSegmentFormat getDataSegmentFormat()

If this method returns true, hen it indicates that the data segment data is interpreted as binary data. Else the data segment data must be interpreted as Text Format.

Specified by:

getDataSegmentFormat in class AbstractMessageParser

Returns:

Returns a format defined by the DataSegmentFormat enumeration.

See Also:

DataSegmentFactory.DataSegmentFormat

clear

public final void clear()

This method sets all settings to their initial values.

Overrides:

clear in class InitiatorMessageParser

deserializeBytes1to3

protected final void deserializeBytes1to3(int line)
                                   throws InternetSCSIException

Parse the bytes 1 till 3 in the Basic Header Segment.

Overrides:

deserializeBytes1to3 in class InitiatorMessageParser

Parameters:

line - The actual line

Throws:

InternetSCSIException - If any violation of the iSCSI-Standard emerge.

deserializeBytes20to23

protected final void deserializeBytes20to23(int line)
                                     throws InternetSCSIException

Parse the bytes 20 till 23 in the Basic Header Segment.

Overrides:

deserializeBytes20to23 in class InitiatorMessageParser

Parameters:

line - The actual line

Throws:

InternetSCSIException - If any violation of the iSCSI-Standard emerge.

checkIntegrity

protected final void checkIntegrity()
                             throws InternetSCSIException

This method checks, if all parsed fields are valid. Because there are several fields, which are reserved for future versions, and these must be zero. Is this the case an exception will be thrown.

Specified by:

checkIntegrity in class AbstractMessageParser

Throws:

InternetSCSIException - If the integrity is violated.

serializeBytes20to23

protected final int serializeBytes20to23()

Serializes the bytes 20 till 23 in the Basic Header Segment.

Overrides:

serializeBytes20to23 in class InitiatorMessageParser

Returns:

The serialized byte representation.