2 * Copyright (c) 2013 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
9 package org.opendaylight.controller.sal.packet;
11 import java.net.InetAddress;
12 import java.net.UnknownHostException;
14 import java.util.Map.Entry;
16 import org.apache.commons.lang3.tuple.Pair;
17 import org.opendaylight.controller.sal.utils.HexEncode;
18 import org.opendaylight.controller.sal.utils.NetUtils;
19 import org.slf4j.Logger;
20 import org.slf4j.LoggerFactory;
23 * Abstract class which represents the generic network packet object It provides
24 * the basic methods which are common for all the packets, like serialize and
30 public abstract class Packet {
31 protected static final Logger logger = LoggerFactory
32 .getLogger(Packet.class);
33 // Access level granted to this packet
34 protected boolean writeAccess;
35 // When deserialized from wire, packet could result corrupted
36 protected boolean corrupted;
37 // The packet that encapsulate this packet
38 protected Packet parent;
39 // The packet encapsulated by this packet
40 protected Packet payload;
41 // Bit coordinates of packet header fields
42 protected Map<String, Pair<Integer, Integer>> hdrFieldCoordMap;
43 // Header fields values: Map<FieldName,Value>
44 protected Map<String, byte[]> hdrFieldsMap;
45 // The class of the encapsulated packet object
46 protected Class<? extends Packet> payloadClass;
53 public Packet(boolean writeAccess) {
54 this.writeAccess = writeAccess;
55 this.corrupted = false;
58 public Packet getParent() {
62 public Packet getPayload() {
66 public void setParent(Packet parent) {
70 public void setPayload(Packet payload) {
71 this.payload = payload;
74 public void setHeaderField(String headerField, byte[] readValue) {
75 hdrFieldsMap.put(headerField, readValue);
79 * This method deserializes the data bits obtained from the wire into the
80 * respective header and payload which are of type Packet
82 * @param byte[] data - data from wire to deserialize
83 * @param int bitOffset bit position where packet header starts in data
85 * @param int size of packet in bits
87 * @throws PacketException
90 public Packet deserialize(byte[] data, int bitOffset, int size)
91 throws PacketException {
93 Integer startOffset = 0, numBits = 0;
96 for (Entry<String, Pair<Integer, Integer>> pairs : hdrFieldCoordMap
98 hdrField = pairs.getKey();
99 startOffset = bitOffset + this.getfieldOffset(hdrField);
100 numBits = this.getfieldnumBits(hdrField);
103 hdrFieldBytes = BitBufferHelper.getBits(data, startOffset,
105 } catch (BufferException e) {
106 throw new PacketException(e.getMessage());
109 * Store the raw read value, checks the payload type and set the
110 * payloadClass accordingly
112 logger.trace("{}: {}: {} (offset {} bitsize {})",
113 new Object[] { this.getClass().getSimpleName(), hdrField,
114 HexEncode.bytesToHexString(hdrFieldBytes),
115 startOffset, numBits });
117 this.setHeaderField(hdrField, hdrFieldBytes);
120 postDeserializeCustomOperation(data, startOffset);
122 int payloadStart = startOffset + numBits;
123 // int payloadSize = size - payloadStart;
124 int payloadSize = data.length * NetUtils.NumBitsInAByte - payloadStart;
126 if (payloadClass != null) {
128 payload = payloadClass.newInstance();
129 } catch (Exception e) {
130 throw new RuntimeException(
131 "Error parsing payload for Ethernet packet", e);
133 payload.deserialize(data, payloadStart, payloadSize);
134 payload.setParent(this);
136 // For now let's discard unparsable payload
142 * This method serializes the header and payload bytes from the respective
143 * packet class, into a single stream of bytes to be sent on the wire
145 * @return byte[] - serialized bytes
146 * @throws PacketException
149 public byte[] serialize() throws PacketException {
150 byte[] payloadBytes = null;
152 int headerSize = this.getHeaderSize();
153 int payloadByteOffset = headerSize / NetUtils.NumBitsInAByte;
156 if (payload != null) {
157 payloadBytes = payload.serialize();
158 payloadSize = payloadBytes.length * NetUtils.NumBitsInAByte;
161 size = headerSize + payloadSize;
162 int length = size / NetUtils.NumBitsInAByte;
163 byte headerBytes[] = new byte[length];
165 if (payload != null) {
166 System.arraycopy(payloadBytes, 0, headerBytes, payloadByteOffset,
167 payloadBytes.length);
172 Integer startOffset, numBits;
174 for (Map.Entry<String, Pair<Integer, Integer>> pairs : hdrFieldCoordMap
176 field = pairs.getKey();
177 fieldBytes = hdrFieldsMap.get(field);
178 // Let's skip optional fields when not set
179 if (fieldBytes != null) {
180 startOffset = this.getfieldOffset(field);
181 numBits = this.getfieldnumBits(field);
183 BitBufferHelper.setBytes(headerBytes, fieldBytes,
184 startOffset, numBits);
185 } catch (BufferException e) {
186 throw new PacketException(e.getMessage());
190 postSerializeCustomOperation(headerBytes);
192 logger.trace("{}: {}", this.getClass().getSimpleName(),
193 HexEncode.bytesToHexString(headerBytes));
198 * This method gets called at the end of the serialization process It is
199 * intended for the child packets to insert some custom data into the output
200 * byte stream which cannot be done or cannot be done efficiently during the
201 * normal Packet.serialize() path. An example is the checksum computation
204 * @param byte[] - serialized bytes
205 * @throws PacketException
207 protected void postSerializeCustomOperation(byte[] myBytes)
208 throws PacketException {
213 * This method re-computes the checksum of the bits received on the wire and
214 * validates it with the checksum in the bits received Since the computation
215 * of checksum varies based on the protocol, this method is overridden
216 * Currently only IPv4 does checksum computation and validation TCP and UDP
217 * need to implement these if required
220 * @param int endBitOffset
221 * @throws PacketException
223 protected void postDeserializeCustomOperation(byte[] data, int endBitOffset)
224 throws PacketException {
229 * Gets the header length in bits
231 * @return int the header length in bits
233 public int getHeaderSize() {
236 * We need to iterate over the fields that were read in the frame
237 * (hdrFieldsMap) not all the possible ones described in
238 * hdrFieldCoordMap. For ex, 802.1Q may or may not be there
240 for (Map.Entry<String, byte[]> fieldEntry : hdrFieldsMap.entrySet()) {
241 if (fieldEntry.getValue() != null) {
242 String field = fieldEntry.getKey();
243 size += getfieldnumBits(field);
250 * This method fetches the start bit offset for header field specified by
251 * 'fieldname'. The offset is present in the hdrFieldCoordMap of the
252 * respective packet class
256 * @return Integer - startOffset of the requested field
258 public int getfieldOffset(String fieldName) {
259 return (((Pair<Integer, Integer>) hdrFieldCoordMap.get(fieldName))
264 * This method fetches the number of bits for header field specified by
265 * 'fieldname'. The numBits are present in the hdrFieldCoordMap of the
266 * respective packet class
270 * @return Integer - number of bits of the requested field
272 public int getfieldnumBits(String fieldName) {
273 return (((Pair<Integer, Integer>) hdrFieldCoordMap.get(fieldName))
278 public String toString() {
279 StringBuffer ret = new StringBuffer();
280 for (Map.Entry<String, byte[]> entry : hdrFieldsMap.entrySet()) {
281 ret.append(entry.getKey() + ": ");
282 if (entry.getValue().length == 6) {
283 ret.append(HexEncode.bytesToHexString(entry.getValue()) + " ");
284 } else if (entry.getValue().length == 4) {
286 ret.append(InetAddress.getByAddress(entry.getValue())
287 .getHostAddress() + " ");
288 } catch (UnknownHostException e) {
292 ret.append(((Long) BitBufferHelper.getLong(entry.getValue()))
296 return ret.toString();
300 * Returns true if the packet is corrupted
304 protected boolean isPacketCorrupted() {