/**
* 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.Arrays;
/**
*
* @author shudong.zhou@bigswitch.com
*/
public class TCP extends BasePacket {
protected short sourcePort;
protected short destinationPort;
protected int sequence;
protected int acknowledge;
protected byte dataOffset;
protected short flags;
protected short windowSize;
protected short checksum;
protected short urgentPointer;
protected byte[] options;
/**
* @return the sourcePort
*/
public short getSourcePort() {
return sourcePort;
}
/**
* @param sourcePort the sourcePort to set
*/
public TCP setSourcePort(short sourcePort) {
this.sourcePort = sourcePort;
return this;
}
/**
* @return the destinationPort
*/
public short getDestinationPort() {
return destinationPort;
}
/**
* @param destinationPort the destinationPort to set
*/
public TCP setDestinationPort(short destinationPort) {
this.destinationPort = destinationPort;
return this;
}
/**
* @return the checksum
*/
public short getChecksum() {
return checksum;
}
public int getSequence() {
return this.sequence;
}
public TCP setSequence(int seq) {
this.sequence = seq;
return this;
}
public int getAcknowledge() {
return this.acknowledge;
}
public TCP setAcknowledge(int ack) {
this.acknowledge = ack;
return this;
}
public byte getDataOffset() {
return this.dataOffset;
}
public TCP setDataOffset(byte offset) {
this.dataOffset = offset;
return this;
}
public short getFlags() {
return this.flags;
}
public TCP setFlags(short flags) {
this.flags = flags;
return this;
}
public short getWindowSize() {
return this.windowSize;
}
public TCP setWindowSize(short windowSize) {
this.windowSize = windowSize;
return this;
}
public short getTcpChecksum() {
return this.checksum;
}
public TCP setTcpChecksum(short checksum) {
this.checksum = checksum;
return this;
}
@Override
public void resetChecksum() {
this.checksum = 0;
super.resetChecksum();
}
public short getUrgentPointer(short urgentPointer) {
return this.urgentPointer;
}
public TCP setUrgentPointer(short urgentPointer) {
this.urgentPointer= urgentPointer;
return this;
}
public byte[] getOptions() {
return this.options;
}
public TCP setOptions(byte[] options) {
this.options = options;
this.dataOffset = (byte) ((20 + options.length + 3) >> 2);
return this;
}
/**
* @param checksum the checksum to set
*/
public TCP 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
*/
public byte[] serialize() {
int length;
if (dataOffset == 0)
dataOffset = 5; // default header length
length = dataOffset << 2;
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.putShort(this.sourcePort);
bb.putShort(this.destinationPort);
bb.putInt(this.sequence);
bb.putInt(this.acknowledge);
bb.putShort((short) (this.flags | (dataOffset << 12)));
bb.putShort(this.windowSize);
bb.putShort(this.checksum);
bb.putShort(this.urgentPointer);
if (dataOffset > 5) {
int padding;
bb.put(options);
padding = (dataOffset << 2) - 20 - options.length;
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_TCP);
// 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 += length & 0xffff;
}
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(16, 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 + 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 TCP))
return false;
TCP other = (TCP) obj;
// May want to compare fields based on the flags set
return (checksum == other.checksum) &&
(destinationPort == other.destinationPort) &&
(sourcePort == other.sourcePort) &&
(sequence == other.sequence) &&
(acknowledge == other.acknowledge) &&
(dataOffset == other.dataOffset) &&
(flags == other.flags) &&
(windowSize == other.windowSize) &&
(urgentPointer == other.urgentPointer) &&
(dataOffset == 5 || Arrays.equals(options,other.options));
}
@Override
public IPacket deserialize(byte[] data, int offset, int length)
throws PacketParsingException {
ByteBuffer bb = ByteBuffer.wrap(data, offset, length);
this.sourcePort = bb.getShort();
this.destinationPort = bb.getShort();
this.sequence = bb.getInt();
this.acknowledge = bb.getInt();
this.flags = bb.getShort();
this.dataOffset = (byte) ((this.flags >> 12) & 0xf);
if (this.dataOffset < 5) {
throw new PacketParsingException("Invalid tcp header length < 20");
}
this.flags = (short) (this.flags & 0x1ff);
this.windowSize = bb.getShort();
this.checksum = bb.getShort();
this.urgentPointer = bb.getShort();
if (this.dataOffset > 5) {
int optLength = (dataOffset << 2) - 20;
if (bb.limit() < bb.position()+optLength) {
optLength = bb.limit() - bb.position();
}
try {
this.options = new byte[optLength];
bb.get(this.options, 0, optLength);
} catch (IndexOutOfBoundsException e) {
this.options = null;
}
}
this.payload = new Data();
int remLength = bb.limit()-bb.position();
this.payload = payload.deserialize(data, bb.position(), remLength);
this.payload.setParent(this);
return this;
}
}