/**
* 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;
/**
*
* @author David Erickson (daviderickson@cs.stanford.edu)
*/
public class UDP extends BasePacket {
public static Map<Short, Class<? extends IPacket>> decodeMap;
public static short DHCP_SERVER_PORT = (short)67;
public static short DHCP_CLIENT_PORT = (short)68;
static {
decodeMap = new HashMap<Short, Class<? extends IPacket>>();
/*
* Disable DHCP until the deserialize code is hardened to deal with garbage input
*/
UDP.decodeMap.put(DHCP_SERVER_PORT, DHCP.class);
UDP.decodeMap.put(DHCP_CLIENT_PORT, DHCP.class);
}
protected short sourcePort;
protected short destinationPort;
protected short length;
protected short checksum;
/**
* @return the sourcePort
*/
public short getSourcePort() {
return sourcePort;
}
/**
* @param sourcePort the sourcePort to set
*/
public UDP setSourcePort(short sourcePort) {
this.sourcePort = sourcePort;
return this;
}
/**
* @return the destinationPort
*/
public short getDestinationPort() {
return destinationPort;
}
/**
* @param destinationPort the destinationPort to set
*/
public UDP setDestinationPort(short destinationPort) {
this.destinationPort = destinationPort;
return this;
}
/**
* @return the length
*/
public short getLength() {
return length;
}
/**
* @return the checksum
*/
public short getChecksum() {
return checksum;
}
/**
* @param checksum the checksum to set
*/
public UDP setChecksum(short checksum) {
this.checksum = checksum;
return this;
}
@Override
public void resetChecksum() {
this.checksum = 0;
super.resetChecksum();
}
/**
* 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
*/
public byte[] serialize() {
byte[] payloadData = null;
if (payload != null) {
payload.setParent(this);
payloadData = payload.serialize();
}
this.length = (short) (8 + ((payloadData == null) ? 0
: payloadData.length));
byte[] data = new byte[this.length];
ByteBuffer bb = ByteBuffer.wrap(data);
bb.putShort(this.sourcePort);
bb.putShort(this.destinationPort);
bb.putShort(this.length);
bb.putShort(this.checksum);
if (payloadData != null)
bb.put(payloadData);
if (this.parent != null && this.parent instanceof IPv4)
((IPv4)this.parent).setProtocol(IPv4.PROTOCOL_UDP);
// compute checksum if needed
if (this.checksum == 0) {
bb.rewind();
int accumulation = 0;
// compute pseudo header mac
if (this.parent != null && this.parent instanceof IPv4) {
IPv4 ipv4 = (IPv4) this.parent;
accumulation += ((ipv4.getSourceAddress() >> 16) & 0xffff)
+ (ipv4.getSourceAddress() & 0xffff);
accumulation += ((ipv4.getDestinationAddress() >> 16) & 0xffff)
+ (ipv4.getDestinationAddress() & 0xffff);
accumulation += ipv4.getProtocol() & 0xff;
accumulation += this.length & 0xffff;
}
for (int i = 0; i < this.length / 2; ++i) {
accumulation += 0xffff & bb.getShort();
}
// pad to an even number of shorts
if (this.length % 2 > 0) {
accumulation += (bb.get() & 0xff) << 8;
}
accumulation = ((accumulation >> 16) & 0xffff)
+ (accumulation & 0xffff);
this.checksum = (short) (~accumulation & 0xffff);
bb.putShort(6, 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 + checksum;
result = prime * result + destinationPort;
result = prime * result + length;
result = prime * result + sourcePort;
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 UDP))
return false;
UDP other = (UDP) obj;
if (checksum != other.checksum)
return false;
if (destinationPort != other.destinationPort)
return false;
if (length != other.length)
return false;
if (sourcePort != other.sourcePort)
return false;
return true;
}
@Override
public IPacket deserialize(byte[] data, int offset, int length) {
ByteBuffer bb = ByteBuffer.wrap(data, offset, length);
this.sourcePort = bb.getShort();
this.destinationPort = bb.getShort();
this.length = bb.getShort();
this.checksum = bb.getShort();
if (UDP.decodeMap.containsKey(this.destinationPort)) {
try {
this.payload = UDP.decodeMap.get(this.destinationPort).getConstructor().newInstance();
} catch (Exception e) {
throw new RuntimeException("Failure instantiating class", e);
}
} else if (UDP.decodeMap.containsKey(this.sourcePort)) {
try {
this.payload = UDP.decodeMap.get(this.sourcePort).getConstructor().newInstance();
} catch (Exception e) {
throw new RuntimeException("Failure instantiating class", e);
}
} else {
this.payload = new Data();
}
this.payload = payload.deserialize(data, bb.position(), bb.limit()-bb.position());
this.payload.setParent(this);
return this;
}
}