TunnelBuildMessageBase

java.lang.Object

net.i2p.data.i2np.I2NPMessageImpl

net.i2p.data.i2np.TunnelBuildMessageBase

All Implemented Interfaces:: I2NPMessage

Direct Known Subclasses:: TunnelBuildMessage, TunnelBuildReplyMessage

public abstract class TunnelBuildMessageBaseextends I2NPMessageImpl

Base for TBM, TBRM, VTBM, VTBRM Retrofitted over them. There's really no difference between the build and build reply.

TBM and VBTM (but not TBRM and VTBRM?) messages are modified in-place by doing a single setRecord(), and retransmitted. Therefore they are NOT good candidates to use FastI2NPMessageImpl; the checksum would have to be invalidated with every setRecord(). Which we could do in TBM and VTBM but not TBRM and VTBRM, but keep it simple for now.

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
Fields
Modifier and Type
Field
Description
protected EncryptedBuildRecord[]
_records
The encrypted records, one per hop, or null until readMessage().
static final int
MAX_RECORD_COUNT
Maximum number of records in any tunnel build message (8 hops).
protected int
RECORD_COUNT
Number of records in _records, zero if not yet set.
static final int
RECORD_SIZE
Size in bytes of one encrypted record: 16 byte IV + 512 byte payload.
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
Modifier
Constructor
Description

TunnelBuildMessageBase(I2PAppContext context)
Create with the default number of records.
protected
TunnelBuildMessageBase(I2PAppContext context, int records)
Leaves the count to be set by readMessage().
Method Summary
All Methods
Modifier and Type
Method
Description
protected int
calculateWrittenLength()
Written length of the message body: one record size per record.
EncryptedBuildRecord
getRecord(int index)
Build record at the given index, may be null.
int
getRecordCount()
How many encrypted build records this message carries, which sets both the length of every hop record array and the tunnel's depth.
void
readMessage(byte[] data, int offset, int dataSize, int type)
Read the records from a byte array.
void
setRecord(int index, EncryptedBuildRecord record)
Store a build record.
protected int
writeMessageBody(byte[] out, int curIndex)
Write the records to the output array, starting at the given index.
Methods inherited from class I2NPMessageImpl
createMessage, fromRawByteArray, fromRawByteArrayNTCP2, getMessageExpiration, getMessageSize, getRawMessageSize, getUniqueId, getUniqueId, readBytes, readBytes, readMessage, setMessageExpiration, setUniqueId, toByteArray, 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.
int
readBytes(byte[] data, int type, int offset, int maxLen)
Limit the max to read from the data buffer, so that we can use a large buffer but prevent the reader from reading off the end.
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)
Write the message to the buffer, returning the number of bytes written.
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, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface I2NPMessage
getType
Modifier and Type
Method
Description
int
getType()
Return the unique identifier for this type of I2NP message, as defined in the I2NP spec.

Field Details
- _records
  protected EncryptedBuildRecord[] _records
  The encrypted records, one per hop, or null until readMessage().
- RECORD_COUNT
  protected int RECORD_COUNT
  Number of records in _records, zero if not yet set.
- MAX_RECORD_COUNT
  public static final int MAX_RECORD_COUNT
  Maximum number of records in any tunnel build message (8 hops).
  See Also:
  Constant Field Values
- RECORD_SIZE
  public static final int RECORD_SIZE
  Size in bytes of one encrypted record: 16 byte IV + 512 byte payload.
  See Also:
  Constant Field Values
Constructor Details
- TunnelBuildMessageBase
  public TunnelBuildMessageBase(I2PAppContext context)
  Create with the default number of records.
  Parameters:
  context - the application context the message is read and written under
- TunnelBuildMessageBase
  protected TunnelBuildMessageBase(I2PAppContext context, int records)
  Leaves the count to be set by readMessage().
  Parameters:
  context - the application context the message is read and written under
  records - the number of records to preallocate, up to MAX_RECORD_COUNT; zero
Method Details
- setRecord
  public void setRecord(int index, EncryptedBuildRecord record)
  Store a build record.
  Parameters:
  index - the zero-based position of the record in the record array
  record - may be null
- getRecord
  public EncryptedBuildRecord getRecord(int index)
  Build record at the given index, may be null.
  Parameters:
  index - the zero-based position of the record in the record array
  Returns:
  may be null
- getRecordCount
  public int getRecordCount()
  How many encrypted build records this message carries, which sets both the length of every hop record array and the tunnel's depth.
  Returns:
  the number of records, from 0 to MAX_RECORD_COUNT
- calculateWrittenLength
  protected int calculateWrittenLength()
  Written length of the message body: one record size per record.
  Specified by:
  calculateWrittenLength in class I2NPMessageImpl
  Returns:
  the number of bytes the body will occupy once serialized
- readMessage
  public void readMessage(byte[] data, int offset, int dataSize, int type) throws I2NPMessageException
  Read the records from a byte array.
  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.
- writeMessageBody
  protected int writeMessageBody(byte[] out, int curIndex) throws I2NPMessageException
  Write the records 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)
  Throws:
  I2NPMessageException - if the body cannot be serialized into out, because it is too small or a field is unserializable

Nested Class Summary

Nested classes/interfaces inherited from class I2NPMessageImpl

Field Summary

Fields inherited from class I2NPMessageImpl

Fields inherited from interface I2NPMessage

Constructor Summary

Method Summary

Methods inherited from class I2NPMessageImpl

Methods inherited from class Object

Methods inherited from interface I2NPMessage

Field Details

_records

RECORD_COUNT

MAX_RECORD_COUNT

RECORD_SIZE

Constructor Details

TunnelBuildMessageBase

Method Details

setRecord

getRecord

getRecordCount

calculateWrittenLength

readMessage

writeMessageBody