/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.apache.directory.server.kerberos.shared.io.encoder;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import org.apache.directory.server.kerberos.shared.messages.Encodable;
import org.apache.directory.server.kerberos.shared.messages.components.Authenticator;
import org.apache.directory.shared.asn1.der.ASN1OutputStream;
import org.apache.directory.shared.asn1.der.DERApplicationSpecific;
import org.apache.directory.shared.asn1.der.DERGeneralString;
import org.apache.directory.shared.asn1.der.DERInteger;
import org.apache.directory.shared.asn1.der.DERSequence;
import org.apache.directory.shared.asn1.der.DERTaggedObject;
/**
* @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
* @version $Rev$, $Date$
*/
public class AuthenticatorEncoder implements Encoder, EncoderFactory
{
/**
* Application code constant for the {@link Authenticator} (2).
*/
private static final int APPLICATION_CODE = 2;
/**
* Encodes an {@link Authenticator} into a byte array.
*
* @param authenticator
* @return The byte array.
* @throws IOException
*/
public byte[] encode( Encodable authenticator ) throws IOException
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ASN1OutputStream aos = new ASN1OutputStream( baos );
DERSequence replySequence = encodeInitialSequence( ( Authenticator ) authenticator );
aos.writeObject( DERApplicationSpecific.valueOf( APPLICATION_CODE, replySequence ) );
aos.close();
return baos.toByteArray();
}
public Encoder getEncoder()
{
return new AuthenticatorEncoder();
}
/**
* Encodes an {@link Authenticator} into a {@link DERSequence}.
*
* -- Unencrypted authenticator
* Authenticator ::= [APPLICATION 2] SEQUENCE
* {
* authenticator-vno[0] INTEGER,
* crealm[1] Realm,
* cname[2] PrincipalName,
* cksum[3] Checksum OPTIONAL,
* cusec[4] INTEGER,
* ctime[5] KerberosTime,
* subkey[6] EncryptionKey OPTIONAL,
* seq-number[7] INTEGER OPTIONAL,
*
* authorization-data[8] AuthorizationData OPTIONAL
* }
*
* @param authenticator
* @return The {@link DERSequence}.
*/
private DERSequence encodeInitialSequence( Authenticator authenticator )
{
String clientRealm = authenticator.getClientPrincipal().getRealm();
DERSequence sequence = new DERSequence();
sequence.add( new DERTaggedObject( 0, DERInteger.valueOf( authenticator.getVersionNumber() ) ) );
sequence.add( new DERTaggedObject( 1, DERGeneralString.valueOf( clientRealm ) ) );
sequence.add( new DERTaggedObject( 2, PrincipalNameEncoder.encode( authenticator.getClientPrincipal() ) ) );
// OPTIONAL
if ( authenticator.getChecksum() != null )
{
sequence.add( new DERTaggedObject( 3, ChecksumEncoder.encode( authenticator.getChecksum() ) ) );
}
sequence.add( new DERTaggedObject( 4, DERInteger.valueOf( authenticator.getClientMicroSecond() ) ) );
sequence.add( new DERTaggedObject( 5, KerberosTimeEncoder.encode( authenticator.getClientTime() ) ) );
// OPTIONAL
if ( authenticator.getSubSessionKey() != null )
{
sequence.add( new DERTaggedObject( 6, EncryptionKeyEncoder
.encodeSequence( authenticator.getSubSessionKey() ) ) );
}
// OPTIONAL
if ( authenticator.getSequenceNumber() > 0 )
{
sequence.add( new DERTaggedObject( 7, DERInteger.valueOf( authenticator.getSequenceNumber() ) ) );
}
// OPTIONAL
if ( authenticator.getAuthorizationData() != null )
{
sequence.add( new DERTaggedObject( 8, AuthorizationDataEncoder
.encode( authenticator.getAuthorizationData() ) ) );
}
return sequence;
}
}