/**
* Copyright 2011, Big Switch Networks, Inc.
* Originally created by David Erickson, Stanford University
*
* 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 net.floodlightcontroller.packet;
import java.nio.ByteBuffer;
import java.util.HashMap;
import java.util.Map;
/**
* Implements ICMP packet format
* @author shudong.zhou@bigswitch.com
*/
public class ICMP extends BasePacket {
protected byte icmpType;
protected byte icmpCode;
protected short checksum;
// The value is the number of bytes of padding
public static final Map<Byte, Short> paddingMap;
public static final byte ECHO_REPLY = 0x0;
public static final byte ECHO_REQUEST = 0x8;
public static final byte TIME_EXCEEDED = 0xB;
public static final byte DESTINATION_UNREACHABLE = 0x3;
public static final byte CODE_PORT_UNREACHABLE = 0x3;
static {
paddingMap = new HashMap<Byte, Short>();
ICMP.paddingMap.put(ICMP.ECHO_REPLY, (short) 0);
ICMP.paddingMap.put(ICMP.ECHO_REQUEST, (short) 0);
ICMP.paddingMap.put(ICMP.TIME_EXCEEDED, (short) 4);
ICMP.paddingMap.put(ICMP.DESTINATION_UNREACHABLE, (short) 4);
}
/**
* @return the icmpType
*/
public byte getIcmpType() {
return icmpType;
}
/**
* @param icmpType to set
*/
public ICMP setIcmpType(byte icmpType) {
this.icmpType = icmpType;
return this;
}
/**
* @return the icmp code
*/
public byte getIcmpCode() {
return icmpCode;
}
/**
* @param icmpCode code to set
*/
public ICMP setIcmpCode(byte icmpCode) {
this.icmpCode = icmpCode;
return this;
}
/**
* @return the checksum
*/
public short getChecksum() {
return checksum;
}
/**
* @param checksum the checksum to set
*/
public ICMP setChecksum(short checksum) {
this.checksum = checksum;
return this;
}
/**
* Serializes the packet. Will compute and set the following fields if they
* are set to specific values at the time serialize is called:
* -checksum : 0
* -length : 0
*/
@Override
public byte[] serialize() {
short padding = 0;
if (paddingMap.containsKey(this.icmpType))
padding = paddingMap.get(this.icmpType);
int length = 4 + padding;
byte[] payloadData = null;
if (payload != null) {
payload.setParent(this);
payloadData = payload.serialize();
length += payloadData.length;
}
byte[] data = new byte[length];
ByteBuffer bb = ByteBuffer.wrap(data);
bb.put(this.icmpType);
bb.put(this.icmpCode);
bb.putShort(this.checksum);
for (int i = 0; i < padding; i++)
bb.put((byte) 0);
if (payloadData != null)
bb.put(payloadData);
if (this.parent != null && this.parent instanceof IPv4)
((IPv4)this.parent).setProtocol(IPv4.PROTOCOL_ICMP);
// compute checksum if needed
if (this.checksum == 0) {
bb.rewind();
int accumulation = 0;
for (int i = 0; i < length / 2; ++i) {
accumulation += 0xffff & bb.getShort();
}
// pad to an even number of shorts
if (length % 2 > 0) {
accumulation += (bb.get() & 0xff) << 8;
}
accumulation = ((accumulation >> 16) & 0xffff)
+ (accumulation & 0xffff);
this.checksum = (short) (~accumulation & 0xffff);
bb.putShort(2, this.checksum);
}
return data;
}
/* (non-Javadoc)
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
final int prime = 5807;
int result = super.hashCode();
result = prime * result + icmpType;
result = prime * result + icmpCode;
result = prime * result + checksum;
return result;
}
/* (non-Javadoc)
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (!super.equals(obj))
return false;
if (!(obj instanceof ICMP))
return false;
ICMP other = (ICMP) obj;
if (icmpType != other.icmpType)
return false;
if (icmpCode != other.icmpCode)
return false;
if (checksum != other.checksum)
return false;
return true;
}
@Override
public IPacket deserialize(byte[] data, int offset, int length)
throws PacketParsingException {
ByteBuffer bb = ByteBuffer.wrap(data, offset, length);
this.icmpType = bb.get();
this.icmpCode = bb.get();
this.checksum = bb.getShort();
short padding = 0;
if (paddingMap.containsKey(this.icmpType))
padding = paddingMap.get(this.icmpType);
bb.position(bb.position() + padding);
this.payload = new Data();
this.payload = payload.deserialize(data, bb.position(), bb.limit()-bb.position());
this.payload.setParent(this);
return this;
}
}