package gnu.crypto.sasl.srp;
// ----------------------------------------------------------------------------
// $Id: ServerStore.java,v 1.4 2005/10/06 04:24:18 rsdio Exp $
//
// Copyright (C) 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// GNU Crypto is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; see the file COPYING. If not, write to the
//
// Free Software Foundation Inc.,
// 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301
// USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library. Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give
// you permission to link this library with independent modules to
// produce an executable, regardless of the license terms of these
// independent modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
// license of that module. An independent module is a module which is
// not derived from or based on this library. If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so. If you do not wish to
// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------
import java.util.HashMap;
/**
* <p>The server-side implementation of the SRP security context store.</p>
*
* @version $Revision: 1.4 $
*/
public class ServerStore {
// Constants and variables
// -------------------------------------------------------------------------
/** The underlying singleton. */
private static ServerStore singleton = null;
/** The map of sid --> Security Context record. */
private static final HashMap sid2ssc = new HashMap();
/** The map of sid --> Session timing record. */
private static final HashMap sid2ttl = new HashMap();
/** A synchronisation lock. */
private static final Object lock = new Object();
/** A counter to generate legible SIDs. */
private static int counter = 0;
// Constructor(s)
// -------------------------------------------------------------------------
/** Private constructor to enforce Singleton pattern. */
private ServerStore() {
super();
// TODO: add a cleaning timer thread
}
// Class methods
// -------------------------------------------------------------------------
/**
* <p>Returns the classloader Singleton.</p>
*
* @return the classloader Singleton instance.
*/
static synchronized final ServerStore instance() {
if (singleton == null) {
singleton = new ServerStore();
}
return singleton;
}
/**
* <p>Returns a legible new session identifier.</p>
*
* @return a new session identifier.
*/
static synchronized final byte[] getNewSessionID() {
final String sid = String.valueOf(++counter);
return new StringBuffer("SID-")
.append("0000000000".substring(0, 10 - sid.length())).append(sid)
.toString().getBytes();
}
// Instance methods
// -------------------------------------------------------------------------
/**
* <p>Returns a boolean flag indicating if the designated session is still
* alive or not.</p>
*
* @param sid the identifier of the session to check.
* @return <code>true</code> if the designated session is still alive.
* <code>false</code> otherwise.
*/
boolean isAlive(final byte[] sid) {
boolean result = false;
if (sid != null && sid.length != 0) {
synchronized(lock) {
final String key = new String(sid);
final StoreEntry ctx = (StoreEntry) sid2ttl.get(key);
if (ctx != null) {
result = ctx.isAlive();
if (!result) { // invalidate it en-passant
sid2ssc.remove(key);
sid2ttl.remove(key);
}
}
}
}
return result;
}
/**
* <p>Records a mapping between a session identifier and the Security Context
* of the designated SRP server mechanism instance.</p>
*
* @param ttl the session's Time-To-Live indicator (in seconds).
* @param ctx the server's security context.
*/
void cacheSession(final int ttl, final SecurityContext ctx) {
synchronized(lock) {
final String key = new String(ctx.getSID());
sid2ssc.put(key, ctx);
sid2ttl.put(key, new StoreEntry(ttl));
}
}
/**
* <p>Updates the mapping between the designated session identifier and the
* designated server's SASL Security Context. In the process, computes
* and return the underlying mechanism server's evidence that shall be
* returned to the client in a session re-use exchange.</p>
*
* @param sid the identifier of the session to restore.
* @return an SRP server's security context.
*/
SecurityContext restoreSession(final byte[] sid) {
final String key = new String(sid);
final SecurityContext result;
synchronized(lock) {
result = (SecurityContext) sid2ssc.remove(key);
sid2ttl.remove(key);
}
return result;
}
/**
* <p>Removes all information related to the designated session ID.</p>
*
* @param sid the identifier of the seesion to invalidate.
*/
void invalidateSession(final byte[] sid) {
final String key = new String(sid);
synchronized(lock) {
sid2ssc.remove(key);
sid2ttl.remove(key);
}
}
}