ReadCapacityStage.java

package org.jscsi.target.connection.stage.fullfeature;

import java.io.IOException;
import java.security.DigestException;

import org.jscsi.exception.InternetSCSIException;
import org.jscsi.parser.BasicHeaderSegment;
import org.jscsi.parser.ProtocolDataUnit;
import org.jscsi.parser.scsi.SCSICommandParser;
import org.jscsi.target.connection.phase.TargetFullFeaturePhase;
import org.jscsi.target.scsi.cdb.ReadCapacity10Cdb;
import org.jscsi.target.scsi.cdb.ReadCapacity16Cdb;
import org.jscsi.target.scsi.cdb.ReadCapacityCdb;
import org.jscsi.target.scsi.cdb.ScsiOperationCode;
import org.jscsi.target.scsi.readCapacity.ReadCapacity10ParameterData;
import org.jscsi.target.scsi.readCapacity.ReadCapacity16ParameterData;
import org.jscsi.target.scsi.readCapacity.ReadCapacityParameterData;
import org.jscsi.target.scsi.sense.AdditionalSenseCodeAndQualifier;
import org.jscsi.target.scsi.sense.senseDataDescriptor.senseKeySpecific.FieldPointerSenseKeySpecificData;
import org.jscsi.target.settings.SettingsException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public final class ReadCapacityStage extends TargetFullFeatureStage {

    private static final Logger LOGGER = LoggerFactory.getLogger(ReadCapacityStage.class);

    public ReadCapacityStage(final TargetFullFeaturePhase targetFullFeaturePhase) {
        super(targetFullFeaturePhase);
    }

    @Override
    public void execute(ProtocolDataUnit pdu) throws IOException, InterruptedException,
        InternetSCSIException, DigestException, SettingsException {

        // find out the type of READ CAPACITY command ((10) or (16))
        final BasicHeaderSegment bhs = pdu.getBasicHeaderSegment();
        final SCSICommandParser parser = (SCSICommandParser)bhs.getParser();
        final ScsiOperationCode opCode = ScsiOperationCode.valueOf(parser.getCDB().get(0));
        ReadCapacityCdb cdb;
        if (opCode == ScsiOperationCode.READ_CAPACITY_10)
            cdb = new ReadCapacity10Cdb(parser.getCDB());
        else if (opCode == ScsiOperationCode.READ_CAPACITY_16)
            cdb = new ReadCapacity16Cdb(parser.getCDB());
        else {
            // programmer error, we should not be here, close the connection
            throw new InternetSCSIException("wrong SCSI Operation Code " + opCode + " in ReadCapacityStage");
        }

        /*
         * Everything is fine, carry on.
         * 
         * The PMI bit of the command descriptor block is ignored, since there
         * is no way to know if "substantial vendor specific delay in data
         * transfer may be encountered" after the address in the LOGICAL BLOCK
         * ADDRESS field. Therefore we always try to return the whole length of
         * the storage medium.
         */

        // make sure that the LOGICAL BLOCK ADDRESS field is valid and send
        // appropriate response
        if (session.getStorageModule().checkBounds(cdb.getLogicalBlockAddress(), 0) != 0) {
            // invalid, log error, send error PDU, and return
            LOGGER.error("encountered " + cdb.getClass() + " in ReadCapacityStage with "
                + "LOGICAL BLOCK ADDRESS = " + cdb.getLogicalBlockAddress());

            final FieldPointerSenseKeySpecificData fp = new FieldPointerSenseKeySpecificData(true,// senseKeySpecificDataValid
                true,// commandData (i.e. invalid field in CDB)
                false,// bitPointerValid
                0,// bitPointer, reserved since invalid
                0);// fieldPointer to the SCSI OpCode field
            final FieldPointerSenseKeySpecificData[] fpArray = new FieldPointerSenseKeySpecificData[] {
                fp
            };
            final ProtocolDataUnit responsePdu = createFixedFormatErrorPdu(fpArray,// senseKeySpecificData
                AdditionalSenseCodeAndQualifier.LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE,// additionalSenseCodeAndQualifier
                bhs.getInitiatorTaskTag(),// initiatorTaskTag
                parser.getExpectedDataTransferLength());// expectedDataTransferLength
            connection.sendPdu(responsePdu);
            return;
        } else {
            // send PDU with requested READ CAPACITY parameter data
            ReadCapacityParameterData parameterData;
            if (cdb instanceof ReadCapacity10Cdb)
                parameterData = new ReadCapacity10ParameterData(session.getStorageModule().getSizeInBlocks()-1,// returnedLogicalBlockAddress
                    session.getStorageModule().getBlockSize());// logicalBlockLengthInBytes
            else
                parameterData = new ReadCapacity16ParameterData(session.getStorageModule().getSizeInBlocks()-1,// returnedLogicalBlockAddress
                    session.getStorageModule().getBlockSize());// logicalBlockLengthInBytes

            sendResponse(bhs.getInitiatorTaskTag(),// initiatorTaskTag,
                parser.getExpectedDataTransferLength(),// expectedDataTransferLength,
                parameterData);// responseData
        }
    }

}