| /* |
| * 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.dhcp.io; |
| |
| |
| import java.io.UnsupportedEncodingException; |
| import java.net.InetAddress; |
| import java.nio.ByteBuffer; |
| import java.util.Iterator; |
| |
| import org.apache.directory.server.dhcp.messages.DhcpMessage; |
| import org.apache.directory.server.dhcp.messages.HardwareAddress; |
| import org.apache.directory.server.dhcp.options.DhcpOption; |
| import org.apache.directory.server.dhcp.options.OptionsField; |
| import org.apache.directory.server.dhcp.options.dhcp.DhcpMessageType; |
| import org.apache.directory.server.i18n.I18n; |
| |
| |
| /** |
| * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> |
| */ |
| public class DhcpMessageEncoder |
| { |
| /** |
| * Converts a DhcpMessage object into a byte buffer. |
| * |
| * @param byteBuffer ByteBuffer to put DhcpMessage into |
| * @param message DhcpMessage to encode into ByteBuffer |
| */ |
| public void encode( ByteBuffer byteBuffer, DhcpMessage message ) |
| { |
| byteBuffer.put( message.getOp() ); |
| |
| HardwareAddress hardwareAddress = message.getHardwareAddress(); |
| |
| byteBuffer.put( ( byte ) ( null != hardwareAddress ? hardwareAddress.getType() : 0 ) ); |
| byteBuffer.put( ( byte ) ( null != hardwareAddress ? hardwareAddress.getLength() : 0 ) ); |
| byteBuffer.put( ( byte ) message.getHopCount() ); |
| byteBuffer.putInt( message.getTransactionId() ); |
| byteBuffer.putShort( ( short ) message.getSeconds() ); |
| byteBuffer.putShort( message.getFlags() ); |
| |
| writeAddress( byteBuffer, message.getCurrentClientAddress() ); |
| writeAddress( byteBuffer, message.getAssignedClientAddress() ); |
| writeAddress( byteBuffer, message.getNextServerAddress() ); |
| writeAddress( byteBuffer, message.getRelayAgentAddress() ); |
| |
| writeBytes( byteBuffer, ( null != hardwareAddress ? hardwareAddress.getAddress() : new byte[] |
| {} ), 16 ); |
| |
| writeString( byteBuffer, message.getServerHostname(), 64 ); |
| writeString( byteBuffer, message.getBootFileName(), 128 ); |
| |
| OptionsField options = message.getOptions(); |
| |
| // update message type option (if set) |
| if ( null != message.getMessageType() ) |
| { |
| options.add( new DhcpMessageType( message.getMessageType() ) ); |
| } |
| |
| encodeOptions( options, byteBuffer ); |
| } |
| |
| |
| /** |
| * Write a zero-terminated string to a field of len bytes. |
| * |
| * @param byteBuffer |
| * @param serverHostname |
| * @param i |
| */ |
| private void writeString( ByteBuffer byteBuffer, String string, int len ) |
| { |
| if ( null == string ) |
| { |
| string = ""; |
| } |
| |
| try |
| { |
| byte[] sbytes = string.getBytes( "ASCII" ); |
| |
| // writeBytes will automatically zero-pad and thus terminate the |
| // string. |
| writeBytes( byteBuffer, sbytes, len ); |
| } |
| catch ( UnsupportedEncodingException e ) |
| { |
| // should not happen |
| throw new RuntimeException( I18n.err( I18n.ERR_635 ), e ); |
| } |
| } |
| |
| |
| /** |
| * Write an InetAddress to the byte buffer. |
| * |
| * @param byteBuffer |
| * @param currentClientAddress |
| */ |
| private void writeAddress( ByteBuffer byteBuffer, InetAddress currentClientAddress ) |
| { |
| if ( null == currentClientAddress ) |
| { |
| byte[] emptyAddress = |
| { 0, 0, 0, 0 }; |
| byteBuffer.put( emptyAddress ); |
| } |
| else |
| { |
| byte[] addressBytes = currentClientAddress.getAddress(); |
| byteBuffer.put( addressBytes ); |
| } |
| } |
| |
| |
| /** |
| * Write an array of bytes to the buffer. Write exactly len bytes, |
| * truncating if more than len, padding if less than len bytes are |
| * available. |
| * |
| * @param byteBuffer |
| * @param currentClientAddress |
| */ |
| private void writeBytes( ByteBuffer byteBuffer, byte[] bytes, int len ) |
| { |
| if ( null == bytes ) |
| { |
| bytes = new byte[] |
| {}; |
| } |
| |
| byteBuffer.put( bytes, 0, Math.min( len, bytes.length ) ); |
| |
| // pad as necessary |
| int remain = len - bytes.length; |
| |
| while ( remain-- > 0 ) |
| { |
| byteBuffer.put( ( byte ) 0 ); |
| } |
| } |
| |
| private static final byte[] VENDOR_MAGIC_COOKIE = |
| { ( byte ) 99, ( byte ) 130, ( byte ) 83, ( byte ) 99 }; |
| |
| |
| public void encodeOptions( OptionsField options, ByteBuffer message ) |
| { |
| message.put( VENDOR_MAGIC_COOKIE ); |
| |
| for ( Iterator i = options.iterator(); i.hasNext(); ) |
| { |
| DhcpOption option = ( DhcpOption ) i.next(); |
| option.writeTo( message ); |
| } |
| |
| // add end option |
| message.put( ( byte ) 0xff ); |
| } |
| } |