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/*
* Copyright 2015 Open Networking Laboratory
*
* Licensed 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.onosproject.bgpio.types;
import org.jboss.netty.buffer.ChannelBuffer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Provides BGP Message Header which is common for all the Messages.
*/
public class BgpHeader {
/* 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ +
| Marker |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
protected static final Logger log = LoggerFactory.getLogger(BgpHeader.class);
public static final int MARKER_LENGTH = 16;
public static final short DEFAULT_HEADER_LENGTH = 19;
private byte[] marker;
private byte type;
private short length;
/**
* Reset fields.
*/
public BgpHeader() {
this.marker = null;
this.length = 0;
this.type = 0;
}
/**
* Constructors to initialize parameters.
*
* @param marker field in BGP header
* @param length message length
* @param type message type
*/
public BgpHeader(byte[] marker, short length, byte type) {
this.marker = marker;
this.length = length;
this.type = type;
}
/**
* Sets marker field.
*
* @param value marker field
*/
public void setMarker(byte[] value) {
this.marker = value;
}
/**
* Sets message type.
*
* @param value message type
*/
public void setType(byte value) {
this.type = value;
}
/**
* Sets message length.
*
* @param value message length
*/
public void setLength(short value) {
this.length = value;
}
/**
* Returns message length.
*
* @return message length
*/
public short getLength() {
return this.length;
}
/**
* Returns message marker.
*
* @return message marker
*/
public byte[] getMarker() {
return this.marker;
}
/**
* Returns message type.
*
* @return message type
*/
public byte getType() {
return this.type;
}
/**
* Writes Byte stream of BGP header to channel buffer.
*
* @param cb ChannelBuffer
* @return length index of message header
*/
public int write(ChannelBuffer cb) {
cb.writeBytes(getMarker(), 0, MARKER_LENGTH);
int headerLenIndex = cb.writerIndex();
cb.writeShort((short) 0);
cb.writeByte(type);
return headerLenIndex;
}
/**
* Read from channel buffer and Returns BGP header.
*
* @param cb ChannelBuffer
* @return object of BGPHeader
*/
public static BgpHeader read(ChannelBuffer cb) {
byte[] marker = new byte[MARKER_LENGTH];
byte type;
short length;
cb.readBytes(marker, 0, MARKER_LENGTH);
length = cb.readShort();
type = cb.readByte();
return new BgpHeader(marker, length, type);
}
}
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