DataMessage

net.i2p.data.i2np.DataMessage

All Implemented Interfaces:: I2NPMessage

public class DataMessageextends FastI2NPMessageImpl

Defines a message containing arbitrary bytes of data. This is what goes in a GarlicClove.

Nested Class Summary
Nested classes/interfaces inherited from class I2NPMessageImpl
I2NPMessageImpl.Builder
Modifier and Type
Class
Description
static interface
I2NPMessageImpl.Builder
Interface for extending the types of messages handled - unused.
Field Summary
Modifier and Type
Field
Description
private byte[]
_data
The opaque payload.
static final int
MESSAGE_TYPE
The message type identifier.
Fields inherited from class FastI2NPMessageImpl
_checksum, _hasChecksum
Modifier and Type
Field
Description
protected byte
_checksum
One-byte checksum.
protected boolean
_hasChecksum
Whether the message includes a checksum.
Fields inherited from class I2NPMessageImpl
_context, _expiration, _log, CHECKSUM_LENGTH, DEFAULT_EXPIRATION_MS, HEADER_LENGTH
Modifier and Type
Field
Description
protected final I2PAppContext
_context
Application context this message belongs to.
protected long
_expiration
Expiration time in milliseconds since the epoch, as an I2P Date.
protected final Log
_log
Log for the message class, taken from the context's log manager.
static final int
CHECKSUM_LENGTH
Number of checksum bytes the message header carries.
static final long
DEFAULT_EXPIRATION_MS
Default lifetime of an unsent message, one minute in milliseconds.
static final int
HEADER_LENGTH
I2NP message header size in bytes.
Fields inherited from interface I2NPMessage
MAX_ID_VALUE, MAX_SIZE
Modifier and Type
Field
Description
static final long
MAX_ID_VALUE
4 bytes unsigned.
static final int
MAX_SIZE
Nominal limit, actual max is much less.
Constructor Summary
Constructors
Constructor
Description
DataMessage(I2PAppContext context)
Create a new DataMessage.
Method Summary
Public Methods
Modifier and Type
Method
Description
protected int
calculateWrittenLength()
Calculate the message body's length, not including the header and footer.
boolean
equals(Object object)

byte[]
getData()
Payload data.
int
getSize()
Payload size in bytes.
int
getType()
Return the unique identifier for this type of I2NP message, as defined in the I2NP spec.
int
hashCode()

void
readMessage(byte[] data, int offset, int dataSize, int type)
Read the body into the data structures, after the initial type byte and the uniqueId / expiration, using the current class's format as defined by the I2NP specification.
void
setData(byte[] data)
The data payload, settable only once so the saved checksum stays valid.
String
toString()

protected int
writeMessageBody(byte[] out, int curIndex)
Write the message body to the output array, starting at the given index.
Methods inherited from class FastI2NPMessageImpl
readBytes, toByteArray, toByteArrayWithSavedChecksum
Modifier and Type
Method
Description
int
readBytes(byte[] data, int type, int offset, int maxLen)
Ignore, but save, the checksum, to be used later if necessary.
int
toByteArray(byte[] buffer)
If available, use the previously-computed or previously-read checksum for speed.
protected int
toByteArrayWithSavedChecksum(byte[] buffer)
Use a previously-computed checksum for speed.
Methods inherited from class I2NPMessageImpl
createMessage, fromRawByteArray, fromRawByteArrayNTCP2, getMessageExpiration, getMessageSize, getRawMessageSize, getUniqueId, getUniqueId, readBytes, readMessage, setMessageExpiration, setUniqueId, toByteArray, toByteArray, toRawByteArray, toRawByteArrayNTCP2
Modifier and Type
Method
Description
static I2NPMessage
createMessage(I2PAppContext context, int type)
Yes, this is fairly ugly, but its the only place it ever happens.
static I2NPMessage
fromRawByteArray(I2PAppContext ctx, byte[] buffer, int offset, int len, I2NPMessageHandler handler)
Read the message with a short 5-byte header.
static I2NPMessage
fromRawByteArrayNTCP2(I2PAppContext ctx, byte[] buffer, int offset, int len, I2NPMessageHandler handler)
Read the message with a short 9-byte header.
long
getMessageExpiration()
Date after which the message should be dropped (and the associated uniqueId forgotten).
int
getMessageSize()
Serialized message size, including the 16-byte header.
int
getRawMessageSize()
The raw header consists of a one-byte type and a 4-byte expiration in seconds only.
long
getUniqueId()
Unique id for this message, lazily initialized when negative.
long
getUniqueId(long msgIDBloomXor)
Replay resistant message Id.
int
readBytes(byte[] data, int type, int offset)
Read the header, then read the rest into buffer, then call readMessage in the implemented message type.
void
readMessage(byte[] data, int offset, int dataSize, int type, I2NPMessageHandler handler)
Read the message fields from the byte array, ignoring the handler.
void
setMessageExpiration(long exp)
The expiration is set to one minute from now in the constructor but it can be overridden here.
void
setUniqueId(long id)
The ID is set to a random value when written but it can be overridden here.
byte[]
toByteArray()
The message serialized into a new byte array.
int
toByteArray(byte[] buffer, int off)
Write the message to the buffer, returning the new offset (NOT the length).
int
toRawByteArray(byte[] buffer)
Write the message with a short 5-byte header.
int
toRawByteArrayNTCP2(byte[] buffer, int off)
Write the message to the buffer, returning the new offset (NOT the length).
Methods inherited from class Object
clone, getClass, notify, notifyAll, wait, wait, wait

Field Details
- MESSAGE_TYPE
  public static final int MESSAGE_TYPE
  The message type identifier.
  See Also:
  Constant Field Values
- _data
  private byte[] _data
  The opaque payload.
Constructor Details
- DataMessage
  public DataMessage(I2PAppContext context)
  Create a new DataMessage.
  Parameters:
  context - the router context
Method Details
- getData
  public byte[] getData()
  Payload data.
  Returns:
  the payload bytes, or null if no payload was set
- setData
  public void setData(byte[] data)
  The data payload, settable only once so the saved checksum stays valid.
  Parameters:
  data - the payload this message will carry to the far endpoint
  Throws:
  IllegalStateException - if data previously set, to protect saved checksum
- getSize
  public int getSize()
  Payload size in bytes.
  Returns:
  the data size
- readMessage
  public void readMessage(byte[] data, int offset, int dataSize, int type) throws I2NPMessageException
  Description copied from interface: I2NPMessage
  Read the body into the data structures, after the initial type byte and the uniqueId / expiration, using the current class's format as defined by the I2NP specification.
  Implementations must not read more than dataSize, or throw I2NPMessageException or IndexOutOfBoundsException if they do.
  Parameters:
  data - data to read from
  offset - where to start in the data array
  dataSize - how long into the data to read
  type - I2NP message type
  Throws:
  I2NPMessageException - if the stream doesn't contain a valid message that this class can read.
- calculateWrittenLength
  protected int calculateWrittenLength()
  Calculate the message body's length, not including the header and footer.
  Specified by:
  calculateWrittenLength in class I2NPMessageImpl
  Returns:
  the number of bytes the body will occupy once serialized
- writeMessageBody
  protected int writeMessageBody(byte[] out, int curIndex)
  Write the message body to the output array, starting at the given index.
  Specified by:
  writeMessageBody in class I2NPMessageImpl
  Parameters:
  out - the buffer to serialize the body into
  curIndex - the offset into out at which to begin writing; leave room for the signature where the header format calls for one
  Returns:
  the index into the array after the last byte written (NOT the length)
- getType
  public int getType()
  Description copied from interface: I2NPMessage
  Return the unique identifier for this type of I2NP message, as defined in the I2NP spec.
  Returns:
  the message type number, as defined in the I2NP spec
- hashCode
  public int hashCode()
  Overrides:
  hashCode in class Object
- equals
  public boolean equals(Object object)
  Overrides:
  equals in class Object
- toString
  public String toString()
  Overrides:
  toString in class Object

Nested Class Summary

Nested classes/interfaces inherited from class I2NPMessageImpl

Field Summary

Fields inherited from class FastI2NPMessageImpl

Fields inherited from class I2NPMessageImpl

Fields inherited from interface I2NPMessage

Constructor Summary

Method Summary

Methods inherited from class FastI2NPMessageImpl

Methods inherited from class I2NPMessageImpl

Methods inherited from class Object

Field Details

MESSAGE_TYPE

_data

Constructor Details

Method Details

getData

setData

getSize

readMessage

calculateWrittenLength

writeMessageBody

getType

hashCode

equals

toString