/*
* 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.keytab;
import java.util.Iterator;
import java.util.List;
import org.apache.directory.server.kerberos.shared.messages.value.EncryptionKey;
import org.apache.mina.core.buffer.IoBuffer;
/**
* Encode keytab fields into a {@link IoBuffer}.
*
* @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
* @version $Rev$, $Date$
*/
class KeytabEncoder
{
/**
* Write the keytab version and entries into a {@link IoBuffer}.
*
* @param keytabVersion
* @param entries
* @return The IoBuffer.
*/
IoBuffer write( byte[] keytabVersion, List<KeytabEntry> entries )
{
IoBuffer buffer = IoBuffer.allocate( 512 );
putKeytabVersion( buffer, keytabVersion );
putKeytabEntries( buffer, entries );
buffer.flip();
return buffer;
}
/**
* Encode the 16-bit file format version. This
* keytab reader currently only support verision 5.2.
*/
private void putKeytabVersion( IoBuffer buffer, byte[] version )
{
buffer.put( version );
}
/**
* Encode the keytab entries.
*
* @param buffer
* @param entries
*/
private void putKeytabEntries( IoBuffer buffer, List<KeytabEntry> entries )
{
Iterator<KeytabEntry> iterator = entries.iterator();
while ( iterator.hasNext() )
{
IoBuffer entryBuffer = putKeytabEntry( iterator.next() );
int size = entryBuffer.position();
entryBuffer.flip();
buffer.putInt( size );
buffer.put( entryBuffer );
}
}
/**
* Encode a "keytab entry," which consists of a principal name,
* principal type, key version number, and key material.
*/
private IoBuffer putKeytabEntry( KeytabEntry entry )
{
IoBuffer buffer = IoBuffer.allocate( 100 );
putPrincipalName( buffer, entry.getPrincipalName() );
buffer.putInt( ( int ) entry.getPrincipalType() );
buffer.putInt( ( int ) ( entry.getTimeStamp().getTime() / 1000 ) );
buffer.put( entry.getKeyVersion() );
putKeyBlock( buffer, entry.getKey() );
return buffer;
}
/**
* Encode a principal name.
*
* @param buffer
* @param principalName
*/
private void putPrincipalName( IoBuffer buffer, String principalName )
{
String[] split = principalName.split( "@" );
String nameComponent = split[0];
String realm = split[1];
String[] nameComponents = nameComponent.split( "/" );
// increment for v1
buffer.putShort( ( short ) nameComponents.length );
putCountedString( buffer, realm );
// write components
for ( int ii = 0; ii < nameComponents.length; ii++ )
{
putCountedString( buffer, nameComponents[ii] );
}
}
/**
* Encode a 16-bit encryption type and symmetric key material.
*/
private void putKeyBlock( IoBuffer buffer, EncryptionKey key )
{
buffer.putShort( ( short ) key.getKeyType().getOrdinal() );
putCountedBytes( buffer, key.getKeyValue() );
}
/**
* Use a prefixed 16-bit length to encode a String. Realm and name
* components are ASCII encoded text with no zero terminator.
*/
private void putCountedString( IoBuffer buffer, String string )
{
byte[] data = string.getBytes();
buffer.putShort( ( short ) data.length );
buffer.put( data );
}
/**
* Use a prefixed 16-bit length to encode raw bytes.
*/
private void putCountedBytes( IoBuffer buffer, byte[] data )
{
buffer.putShort( ( short ) data.length );
buffer.put( data );
}
}