/**
* Copyright (c) 2012, University of Konstanz, Distributed Systems Group
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University of Konstanz nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.jscsi.parser.nop;
import org.jscsi.exception.InternetSCSIException;
import org.jscsi.parser.Constants;
import org.jscsi.parser.InitiatorMessageParser;
import org.jscsi.parser.ProtocolDataUnit;
import org.jscsi.parser.datasegment.DataSegmentFactory.DataSegmentFormat;
import org.jscsi.utils.Utils;
/**
* <h1>NOPOutParser</h1>
* <p>
* This class parses a NOP-Out message defined in the iSCSI Standard (RFC3720).
* <p>
* 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".
* <p>
* A NOP-Out is also sent by an initiator in response to a NOP-In.
* <p>
* A NOP-Out may also be used to confirm a changed <code>ExpStatSN</code> if another PDU will not be available
* for a long time.
* <p>
* Upon receipt of a NOP-In with the Target Transfer Tag set to a valid value (not the reserved
* <code>0xffffffff</code>), 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.
* <p>
* These fields have these specific meanings: <blockquote> <b>Initiator Task Tag:</b><br/>
* 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 <code>0xffffffff</code>.
* <p>
* 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).
* <p>
* If the Initiator Task Tag contains <code>0xffffffff</code>, the <code>I bit</code> MUST be set to
* <code>1</code> and the <code>CmdSN</code> is not advanced after this PDU is sent.
* <p>
* <b>Ping Data</b><br/>
* Ping data are reflected in the NOP-In Response. The length of the reflected data are limited to
* <code>MaxRecvDataSegmentLength</code>. The length of ping data are indicated by the
* <code>DataSegmentLength</code>. <code>0</code> is a valid value for the <code>DataSegmentLength</code> and
* indicates the absence of ping data. </blockquote>
*
* @author Volker Wildi
*/
public final class NOPOutParser extends InitiatorMessageParser {
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
/** The TargetTransferTag. */
protected int targetTransferTag;
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
/**
* Default constructor, creates a new, empty <code>NOPOutParser</code> object.
*
* @param initProtocolDataUnit
* The reference <code>ProtocolDataUnit</code> instance, which
* contains this <code>NOPOutParser</code> subclass object.
*/
public NOPOutParser(final ProtocolDataUnit initProtocolDataUnit) {
super(initProtocolDataUnit);
}
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
/**
* A target assigned identifier for the operation.
* <p>
* 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 <code>0xffffffff</code>.
* <p>
* When the Target Transfer Tag is set to a value other than <code>0xffffffff</code>, the LUN field MUST
* also be copied from the NOP-In.
*
* @return The target transfer tag of this object.
*/
public final int getTargetTransferTag() {
return targetTransferTag;
}
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
/** {@inheritDoc} */
@Override
public final String toString() {
final StringBuilder sb = new StringBuilder(Constants.LOG_INITIAL_SIZE);
Utils.printField(sb, "LUN", logicalUnitNumber, 1);
Utils.printField(sb, "Target Transfer Tag", targetTransferTag, 1);
sb.append(super.toString());
return sb.toString();
}
/** {@inheritDoc} */
@Override
public final DataSegmentFormat getDataSegmentFormat() {
return DataSegmentFormat.BINARY;
}
/** {@inheritDoc} */
@Override
public final void clear() {
super.clear();
targetTransferTag = 0x00000000;
}
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
/** {@inheritDoc} */
@Override
protected final void deserializeBytes1to3(final int line) throws InternetSCSIException {
Utils.isReserved(line & Constants.LAST_THREE_BYTES_MASK);
}
/** {@inheritDoc} */
@Override
protected final void deserializeBytes20to23(final int line) throws InternetSCSIException {
targetTransferTag = line;
}
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
/** {@inheritDoc} */
@Override
protected final void checkIntegrity() throws InternetSCSIException {
// do nothing...
}
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
/** {@inheritDoc} */
@Override
protected final int serializeBytes20to23() {
return targetTransferTag;
}
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
// --------------------------------------------------------------------------
}