Package org.opendaylight.openflowplugin.libraries.liblldp

Class Packet

java.lang.Object
org.opendaylight.openflowplugin.libraries.liblldp.Packet
Direct Known Subclasses:
Ethernet, LLDP, LLDPTLV
public abstract class Packet extends Object
Abstract class which represents the generic network packet object. It provides the basic methods which are common for all the packets, like serialize and deserialize.

  • Field Details

    • writeAccess

      protected final boolean writeAccess

    • corrupted

      protected boolean corrupted

    • parent

      protected Packet parent

    • payload

      protected Packet payload

    • rawPayload

      protected byte[] rawPayload

    • hdrFieldCoordMap

      protected Map<String,org.apache.commons.lang3.tuple.Pair<Integer,Integer>> hdrFieldCoordMap

    • hdrFieldsMap

      protected Map<String,byte[]> hdrFieldsMap

    • payloadFactory

      protected Supplier<Packet> payloadFactory

  • Constructor Details

    • Packet

      public Packet()

    • Packet

      public Packet(boolean writeAccess)

  • Method Details

    • getParent

      public Packet getParent()

    • getPayload

      public Packet getPayload()

    • setParent

      public void setParent(Packet parent)

    • setPayload

      public void setPayload(Packet payload)

    • setHeaderField

      public void setHeaderField(String headerField, byte[] readValue)

    • deserialize

      public Packet deserialize(byte[] data, int bitOffset, int size) throws PacketException
      This method deserializes the data bits obtained from the wire into the respective header and payload which are of type Packet.
      Parameters:
      data - - data from wire to deserialize
      bitOffset - bit position where packet header starts in data array
      size - size of packet in bits
      Returns:
      Packet
      Throws:
      PacketException - if deserialization fails

    • serialize

      public byte[] serialize() throws PacketException
      This method serializes the header and payload from the respective packet class, into a single stream of bytes to be sent on the wire.
      Returns:
      The byte array representing the serialized Packet
      Throws:
      PacketException - if serialization fails

    • postSerializeCustomOperation

      protected void postSerializeCustomOperation(byte[] myBytes) throws PacketException
      This method gets called at the end of the serialization process It is intended for the child packets to insert some custom data into the output byte stream which cannot be done or cannot be done efficiently during the normal Packet.serialize() path. An example is the checksum computation for IPv4
      Parameters:
      myBytes - serialized bytes
      Throws:
      PacketException - on failure

    • postDeserializeCustomOperation

      protected void postDeserializeCustomOperation(byte[] data, int startBitOffset) throws PacketException
      This method re-computes the checksum of the bits received on the wire and validates it with the checksum in the bits received Since the computation of checksum varies based on the protocol, this method is overridden. Currently only IPv4 and ICMP do checksum computation and validation. TCP and UDP need to implement these if required.
      Parameters:
      data - The byte stream representing the Ethernet frame
      startBitOffset - The bit offset from where the byte array corresponding to this Packet starts in the frame
      Throws:
      PacketException - on failure

    • getHeaderSize

      public int getHeaderSize()
      Gets the header length in bits.
      Returns:
      int the header length in bits

    • getfieldOffset

      public int getfieldOffset(String fieldName)
      This method fetches the start bit offset for header field specified by 'fieldname'. The offset is present in the hdrFieldCoordMap of the respective packet class
      Returns:
      Integer - startOffset of the requested field

    • getfieldnumBits

      public int getfieldnumBits(String fieldName)
      This method fetches the number of bits for header field specified by 'fieldname'. The numBits are present in the hdrFieldCoordMap of the respective packet class
      Returns:
      Integer - number of bits of the requested field

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • getRawPayload

      public byte[] getRawPayload()
      Returns the raw payload carried by this packet in case payload was not parsed. Caller can call this function in case the getPaylod() returns null.
      Returns:
      The raw payload if not parsable as an array of bytes, null otherwise

    • setRawPayload

      public void setRawPayload(byte[] bytes)
      Set a raw payload in the packet class.
      Parameters:
      bytes - The raw payload as byte array

    • isCorrupted

      public boolean isCorrupted()
      Return whether the deserialized packet is to be considered corrupted. This is the case when the checksum computed after reconstructing the packet received from wire is not equal to the checksum read from the stream. For the Packet class which do not have a checksum field, this function will always return false.
      Returns:
      true if the deserialized packet's recomputed checksum is not equal to the packet carried checksum

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object