org.jscsi.target.settings.ConnectionSettingsNegotiator Maven / Gradle / Ivy
package org.jscsi.target.settings;
import java.util.List;
import java.util.Vector;
import org.jscsi.parser.ProtocolDataUnit;
import org.jscsi.parser.login.LoginStage;
import org.jscsi.target.TargetServer;
import org.jscsi.target.connection.TargetSession;
import org.jscsi.target.settings.entry.BooleanEntry;
import org.jscsi.target.settings.entry.Entry;
import org.jscsi.target.settings.entry.NumericalEntry;
import org.jscsi.target.settings.entry.NumericalRangeEntry;
import org.jscsi.target.settings.entry.StringEntry;
import org.jscsi.target.settings.entry.Use;
/**
* In addition to offering all methods of their {@link SettingsNegotiator} parent class,
* {@link ConnectionSettingsNegotiator} instances provide all methods necessary for text parameter negotiation and for
* creating {@link Settings} objects, which allow access to the current parameters.
*
* Each instance of this class belongs to one Connection, for which it manages all connection-specific
* parameters. A similar association exists between the connection's enclosing {@link TargetSession} and the
* {@link #sessionSettingsNegotiator} member variable.
*
* A negotiation sequence consists of the following steps, performed in the given order:
*
*
* - Call {@link #beginNegotiation()} until it returns
true.
* - One or, if the initiator is using multiple PDU sequences, multiple calls of
* {@link #negotiate(TargetServer, LoginStage, boolean, boolean, List, List)}. The method will return
false
* if there was a problem.
* - Call {@link #checkConstraints()} to check more complex requirements. The method will return
false if
* there was a problem.
* - Call {@link #finishNegotiation(boolean)} with the appropriate parameter. This step is mandatory.
*
*
* @author Andreas Ergenzinger, University of Konstanz
*/
public final class ConnectionSettingsNegotiator extends SettingsNegotiator {
/**
* The {@link SessionSettingsNegotiator} maintaining all {@link Entry} objects for session-wide parameters.
*/
private final SessionSettingsNegotiator sessionSettingsNegotiator;
/**
* A current snapshot of all connection-specific parameters.
*/
private ConnectionSettingsBuilderComponent connectionSettingBuilderComponent;
/**
* A current snapshot of all parameters, both connection-specific and session-wide.
*/
private Settings settings;
/**
* The {@link ConnectionSettingsNegotiator} constructor.
*
* @param sessionSettingsNegotiator the {@link SessionSettingsNegotiator} maintaining all {@link Entry} objects for
* session-wide parameters
*/
public ConnectionSettingsNegotiator (final SessionSettingsNegotiator sessionSettingsNegotiator) {
super();// initializes entries
this.sessionSettingsNegotiator = sessionSettingsNegotiator;
// initialize settings
updateSettingsBuilderComponent();
updateSettings();
}
/**
* This method must be called at the beginning of a parameter negotiation sequence.
*
* This method will block until no other {@link ConnectionSettingsNegotiator} is negotiating and will return
* true if negotiations may proceed, or false, if the request for the permission to
* negotiate was denied.
*
* @return true if and only if the caller is allowed to negotiate parameters
* @see #finishNegotiation(boolean)
*/
public boolean beginNegotiation () {
final boolean hasLock = sessionSettingsNegotiator.lock();
if (hasLock) {
// back up entries with connection and with session scope
backUpEntries();
sessionSettingsNegotiator.backUpEntries();
}
return hasLock;
}
/**
* This method must be called at the end of a negotiation sequence. If there was a problem during negotiations, all
* changes to the managed {@link Entry} objects must be discarded by setting the commitChanges parameter to
* false. If it is true, then the parameter changes will be incorporated into the updated
* {@link #settings}.
*
* Calling this method should be ensured by a try ... catch ...
* finally block.
*
* @param commitChanges true if and only if the negotiated parameter changes are to be committed
*/
public void finishNegotiation (final boolean commitChanges) {
// commit or roll back connection-specific entries
commitOrRollBackChanges(commitChanges);
// commit or roll back session-wide entries
sessionSettingsNegotiator.commitOrRollBackChanges(commitChanges);
// update settings
updateSettingsBuilderComponent();
sessionSettingsNegotiator.updateSettingsBuilderComponent();
updateSettings();
// allow other Threads to negotiate
sessionSettingsNegotiator.unlock();
}
/**
* Processes one or more key-value pairs sent by the initiator, formulates response key-value pairs
* and changes the involved {@link Entry} instances accordingly.
*
* @param loginStage specifies the current stage or phase
* @param leadingConnection true if and only if the connection is the first connection of the enclosing
* session
* @param initialPdu true if and only if the key-value pairs were sent in the first
* {@link ProtocolDataUnit} received on this connection
* @param requestKeyValuePairs contains the key-value pairs from the initiator; processed elements will be
* removed
* @param responseKeyValuePairs will contain the key-value pairs from the jSCSI target
* @return true if everything went fine and false if there was an irreconcilable problem
*/
public boolean negotiate (TargetServer target, final LoginStage loginStage, final boolean leadingConnection, final boolean initialPdu, final List requestKeyValuePairs, final List responseKeyValuePairs) {
// split up key=value pairs from requester
final List keys = new Vector<>();
final List values = new Vector<>();
for (String keyValuePair : requestKeyValuePairs) {
final String[] split = TextParameter.splitKeyValuePair(keyValuePair);
if (split == null) {
System.err.println("malformatted key=value pair: " + keyValuePair);
return false;
}
keys.add(split[0]);
values.add(split[1]);
}
// get respective entry (declared by initiator, or negotiated) and
// let it process the key=value pair
Entry entry;
boolean everythingOkay = true;
while (keys.size() > 0) {
entry = getEntry(keys.get(0));
// respond to unknown keys
if (entry == null) {
responseKeyValuePairs.add(TextParameter.toKeyValuePair(keys.get(0), TextKeyword.NOT_UNDERSTOOD));
} else {// appropriate entry was found
// process key=value pair and remember if there is any trouble
everythingOkay &= entry.negotiate(target, loginStage, leadingConnection, initialPdu, keys.get(0), values.get(0), responseKeyValuePairs);
}
// remove processed key and values
keys.remove(0);
values.remove(0);
}
// check if initiator has sent all mandatory parameters
// and append target declarations
if (initialPdu) {
// initiator must provide the InitiatorName in the first Login PDU
// (InitiatorAlias is optional)
everythingOkay &= getEntry(TextKeyword.INITIATOR_NAME).checkAccepted();
// in a normal session the initiator must declare TargetName
// the target must reply with TargetPortalGroupTag and should
// append TargetAlias
boolean normalSession = TextKeyword.NORMAL.equals(((StringEntry) getEntry(TextKeyword.SESSION_TYPE)).getStringValue());
if (normalSession) {
// check if proposed TargetName is correct
final StringEntry targetNameEntry = (StringEntry) getEntry(TextKeyword.TARGET_NAME);
final String targetName = targetNameEntry.getStringValue();
if (targetName == null || // not declared
!target.isValidTargetName(targetName)) // wrong name
everythingOkay = false;
// send TargetAlias
String targetAlias = null;
if (everythingOkay) targetAlias = target.getTarget(targetName).getTargetAlias();// might
// be
// undefined
if (targetAlias != null) {
responseKeyValuePairs.add(TextParameter.toKeyValuePair(TextKeyword.TARGET_ALIAS, targetAlias));
}
// send TargetPortalGroupTag
responseKeyValuePairs.add(TextParameter.toKeyValuePair(TextKeyword.TARGET_PORTAL_GROUP_TAG, Integer.valueOf(target.getConfig().getTargetPortalGroupTag()).toString()));
}
}
return everythingOkay;
}
@Override
public boolean checkConstraints () {
return sessionSettingsNegotiator.checkConstraints();
/*
* in multi-connection session, the InitiatorName of follow-up connections should be checked against the
* InitiatorName of the leading connection
*/
}
/**
* Returns the {@link Entry} responsible for negotiating the specified key identifying either a session-wide
* or connection-specific parameter, or null if no such {@link Entry} can be found.
*
* @param key identifies an {@link Entry}
* @return the requested {@link Entry} or null
*/
private Entry getEntry (final String key) {
Entry entry;
// check connection-only entries
entry = getEntry(key, entries);
if (entry == null) // keep looking in session-wide entries
entry = sessionSettingsNegotiator.getEntry(key);
return entry;
}
/**
* This method checks if any parameter changes have been committed since the last call and, if so, creates a new
* {@link Settings} object reflecting the current parameters.
*
* @return The current parameters
*/
public Settings getSettings () {
// check if settings are up to date
if (sessionSettingsNegotiator.getCurrentSettingsId() > settings.getSettingsId()) updateSettings();
return settings;
}
/**
* Updates {@link #settings} by replacing it with a more current copy of the managed parameters.
*/
private synchronized void updateSettings () {
settings = new Settings(connectionSettingBuilderComponent, sessionSettingsNegotiator.getSessionSettingsBuilderComponent());
}
@Override
protected void initializeEntries () {
/*
* Determines type and use of the data digest.
*/
entries.add(new StringEntry(new KeySet(TextKeyword.DATA_DIGEST),// keySet
NegotiationType.NEGOTIATED,// negotiationType
Use.LOPNS,// use
NegotiationStatus.DEFAULT,// negotiationStatus
new String[] { TextKeyword.NONE },// supportedValues,
TextKeyword.NONE));// defaultValue
/*
* Determines type and use of the header digest.
*/
entries.add(new StringEntry(new KeySet(TextKeyword.HEADER_DIGEST),// keySet
NegotiationType.NEGOTIATED,// negotiationType
Use.LOPNS,// use
NegotiationStatus.DEFAULT,// negotiationStatus
new String[] { TextKeyword.NONE },// supportedValues,
TextKeyword.NONE));// defaultValue
/*
* Turns the target-to-initiator markers on or off.
*/
entries.add(new BooleanEntry(new KeySet(TextKeyword.IF_MARKER),// keySet
Use.LOPNS,// use
NegotiationStatus.DEFAULT,// negotiationStatus
false,// negotiationValue
BooleanResultFunction.AND,// resultFunction
false));// defaultValue
/*
* Interval value (in 4-byte words) for target-to-initiator markers. The interval is measured from the end of
* one marker to the beginning of the next one. The offer can have only a range; the response can have only a
* single value (picked from the offered range) or Reject. Will always be Irrelevant.
*/
entries.add(new NumericalRangeEntry(new KeySet(TextKeyword.IF_MARK_INT),// keySet
Use.LOPNS,// use
NegotiationStatus.IRRELEVANT,// negotiationStatus
2048,// negotiationValue
NumericalValueRange.create(1, 65535),// protocolValueRange
2048));// defaultValue
/*
* The maximum amount of data that either the initiator or the target can receive in any iSCSI PDU. Zero (don't
* care) can be used. I&T can specify (declare) the Max they can receive. This is a connection- and direction-
* specific parameter. The actual value used by the target will be min(This value, MaxBurstLength) for data-in
* and solicited data-out data. Min(This value, FirstBurstLength) for unsolicited data.
*/
entries.add(new NumericalEntry(new KeySet(TextKeyword.MAX_RECV_DATA_SEGMENT_LENGTH),// keySet
NegotiationType.DECLARED,// negotiationType
Use.LOPNS_AND_FFP,// use
NegotiationStatus.DEFAULT,// negotiationStatus
8192,// negotiationValue (default value, will be used if I sends
// 0)
NumericalValueRange.create(512, 16777215),// protocolValueRange
// 512 to 2^24 - 1
NumericalResultFunction.MIN,// resultFunction
8192,// defaultValue, 8K
true));// zeroMeansDontCare
/*
* Turns the initiator-to-target markers on or off.
*/
entries.add(new BooleanEntry(new KeySet(TextKeyword.OF_MARKER),// keySet
Use.LOPNS,// use
NegotiationStatus.DEFAULT,// negotiationStatus
false,// negotiationValue
BooleanResultFunction.AND,// resultFunction
false));// defaultValue
/*
* Interval value (in 4-byte words) for initiator-to-target markers. The interval is measured from the end of
* one marker to the beginning of the next one. The offer can have only a range; the response can have only a
* single value (picked from the offered range) or Reject. Will always be Irrelevant.
*/
entries.add(new NumericalRangeEntry(new KeySet(TextKeyword.OF_MARK_INT),// keySet
Use.LOPNS,// use
NegotiationStatus.IRRELEVANT,// negotiationStatus
2048,// negotiationValue
NumericalValueRange.create(1, 65535),// protocolValueRange
2048));// defaultValue
/*
* This entry is not used for Settings initialization, TargetName has a session-wide scope. This entry
* intercepts the TargetName parameter the initiator has to declare at the beginning of normal sessions.
*/
entries.add(new StringEntry(new KeySet(TextKeyword.TARGET_NAME),// keySet
NegotiationType.DECLARED,// negotiationType
Use.INITIAL,// use
NegotiationStatus.NOT_NEGOTIATED,// negotiationStatus
null,// supportedValues, anything goes
null));// defaultValue
}
/**
* Updates {@link ConnectionSettingsBuilderComponent} with the currently valid parameters retrieved from the
* elements of {@link SettingsNegotiator#entries}.
*/
protected void updateSettingsBuilderComponent () {
connectionSettingBuilderComponent = new ConnectionSettingsBuilderComponent(entries);
}
}