/*
* SSHTools - Java SSH2 API
*
* Copyright (C) 2002-2003 Lee David Painter and Contributors.
*
* Contributions made by:
*
* Brett Smith
* Richard Pernavas
* Erwin Bolwidt
*
* This program 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
* of the License, or (at your option) any later version.
*
* This program 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; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package com.sshtools.j2ssh.transport.kex;
import com.sshtools.j2ssh.configuration.ConfigurationException;
import com.sshtools.j2ssh.configuration.ConfigurationLoader;
import com.sshtools.j2ssh.configuration.ExtensionAlgorithm;
import com.sshtools.j2ssh.configuration.SshAPIConfiguration;
import com.sshtools.j2ssh.transport.AlgorithmNotSupportedException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
/**
*
*
* @author $author$
* @version $Revision: 1.28 $
*/
public class SshKeyExchangeFactory {
private static Map kexs;
private static String defaultAlgorithm;
private static Log log = LogFactory.getLog(SshKeyExchangeFactory.class);
static {
kexs = new HashMap();
log.info("Loading key exchange methods");
kexs.put("diffie-hellman-group1-sha1", DhGroup1Sha1.class);
try {
// Load external compression from configuration file
if (ConfigurationLoader.isConfigurationAvailable(
SshAPIConfiguration.class)) {
SshAPIConfiguration config = (SshAPIConfiguration) ConfigurationLoader.getConfiguration(SshAPIConfiguration.class);
if (config != null) {
List list = config.getKeyExchangeExtensions();
if (list != null) {
Iterator it = list.iterator();
while (it.hasNext()) {
ExtensionAlgorithm algorithm = (ExtensionAlgorithm) it.next();
String name = algorithm.getAlgorithmName();
if (kexs.containsKey(name)) {
log.debug("Standard key exchange " + name +
" is being overidden by " +
algorithm.getImplementationClass());
} else {
log.debug(algorithm.getAlgorithmName() +
" key exchange is implemented by " +
algorithm.getImplementationClass());
}
try {
kexs.put(algorithm.getAlgorithmName(),
ConfigurationLoader.getExtensionClass(
algorithm.getImplementationClass()));
} catch (ClassNotFoundException cnfe) {
log.error("Could not locate " +
algorithm.getImplementationClass());
}
}
}
defaultAlgorithm = config.getDefaultKeyExchange();
}
}
} catch (ConfigurationException ex) {
}
if ((defaultAlgorithm == null) || !kexs.containsKey(defaultAlgorithm)) {
log.debug(
"The default key exchange is not set! using first in list");
Iterator it = kexs.keySet().iterator();
defaultAlgorithm = (String) it.next();
}
}
/**
* Creates a new SshKeyExchangeFactory object.
*/
protected SshKeyExchangeFactory() {
}
/**
*
*/
public static void initialize() {
}
/**
*
*
* @return
*/
public static String getDefaultKeyExchange() {
return defaultAlgorithm;
}
/**
*
*
* @return
*/
public static List getSupportedKeyExchanges() {
return new ArrayList(kexs.keySet());
}
/**
*
*
* @param methodName
*
* @return
*
* @throws AlgorithmNotSupportedException
*/
public static SshKeyExchange newInstance(String methodName)
throws AlgorithmNotSupportedException {
try {
return (SshKeyExchange) ((Class) kexs.get(methodName)).newInstance();
} catch (Exception e) {
throw new AlgorithmNotSupportedException(methodName +
" is not supported!");
}
}
}