UDPPacket (Javadocs [I2P+ 2.11.0+] - API Version 0.9.68+)

java.lang.Object
- net.i2p.router.transport.udp.UDPPacket

All Implemented Interfaces:

CDPQEntry, CDQEntry, PQEntry
```
class UDPPacket
extends Object
implements CDPQEntry
```
UDP packet wrapper with caching and metadata support. This class wraps standard DatagramPacket objects and adds I2P-specific metadata for efficient packet handling and reuse. It implements an object cache pattern to reduce garbage collection overhead and improve performance in high-throughput scenarios. Core Features:
- Packet wrapping with metadata preservation
- Object caching for reuse and GC reduction
- Priority-based queuing and processing
- Fragmentation and reassembly support
- Bandwidth reservation and throttling integration
- Timestamp and routing metadata
Caching Strategy:
- Internal object pool for packet reuse
- Cache size limits and eviction policies
- Thread-safe cache operations
- Memory-efficient packet allocation
Metadata Support:
- Message type and protocol information
- Priority levels for QoS handling
- Fragment identification and sequencing
- Bandwidth allocation tracking
- Routing and forwarding information
Performance Optimizations:
- Minimal object creation overhead
- Efficient data copying and cloning
- Cache-friendly packet lifecycle management
- Reduced garbage collection pressure

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`IV_SIZE` Size of initialization vector in bytes.
`static int`	`MAC_SIZE` Size of MAC (Message Authentication Code) in bytes.
`(package private) static int`	`MAX_PACKET_SIZE` Maximum UDP packet size accepted.
`static int`	`MAX_PAYLOAD_TYPE`
`static int`	`PAYLOAD_TYPE_DATA`
`static int`	`PAYLOAD_TYPE_RELAY_INTRO`
`static int`	`PAYLOAD_TYPE_RELAY_REQUEST`
`static int`	`PAYLOAD_TYPE_RELAY_RESPONSE`
`static int`	`PAYLOAD_TYPE_SESSION_CONFIRMED`
`static int`	`PAYLOAD_TYPE_SESSION_CREATED`
`static int`	`PAYLOAD_TYPE_SESSION_DESTROY`
`static int`	`PAYLOAD_TYPE_SESSION_REQUEST`
`static int`	`PAYLOAD_TYPE_TEST`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static UDPPacket`	`acquire(RouterContext ctx, boolean inbound)` Acquires a UDPPacket instance, either from the cache or by creating a new instance.
`static void`	`clearCache()` Clears the internal packet cache if caching is enabled.
`void`	`drop()` Convenience method to release the packet.
`FIFOBandwidthLimiter.Request`	`getBandwidthRequest()` Returns the current bandwidth request associated with this packet.
`long`	`getBegin()` Gets the packet initialization timestamp in milliseconds.
`long`	`getEnqueueTime()` Gets the time the packet was enqueued.
`(package private) int`	`getFragmentCount()`
`long`	`getLifetime()` Returns how long this packet has existed since initialization.
`int`	`getMarkedType()` Gets the currently marked type of the packet.
`(package private) int`	`getMessageType()`
`DatagramPacket`	`getPacket()` Gets the underlying `DatagramPacket`.
`int`	`getPriority()` Gets the packet priority.
`(package private) RemoteHostId`	`getRemoteHost()` Lazily obtains the `RemoteHostId` representing the sender's address and port.
`long`	`getSeqNum()` Gets the packet sequence number.
`(package private) long`	`getTimeSinceReceived()` Returns the amount of time elapsed since the packet was received.
`void`	`markType(int type)` Marks the packet with a custom type for internal identification.
`static String`	`payloadTypeToString(int type)` Converts payload type integer constant to human-readable string.
`(package private) void`	`received()` Marks the packet as received, recording the current time.
`static void`	`reduceCacheSize()` Reduces cache size under memory pressure.
`void`	`release()` Releases this packet back to the object cache and aborts any outstanding bandwidth request.
`void`	`requestOutboundBandwidth()` Requests outbound bandwidth for sending this packet.
`void`	`resetBegin()` Resets the initialization timestamp to current time.
`void`	`setEnqueueTime(long now)` Sets the enqueue time timestamp, indicating when the packet was queued for processing.
`(package private) void`	`setFragmentCount(int count)`
`(package private) void`	`setMessageType(int type)`
`void`	`setPriority(int pri)` Sets the packet priority.
`void`	`setSeqNum(long num)` Sets the packet sequence number.
`String`	`toString()` Returns a detailed string representation of this packet, including address, size, priority, message and mark types, fragment counts, and timing information.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - IV_SIZE
```
public static final int IV_SIZE
```
    Size of initialization vector in bytes.
    
    See Also:
    
    Constant Field Values
  - MAC_SIZE
```
public static final int MAC_SIZE
```
    Size of MAC (Message Authentication Code) in bytes.
    
    See Also:
    
    Constant Field Values
  - MAX_PACKET_SIZE
```
static final int MAX_PACKET_SIZE
```
    Maximum UDP packet size accepted. Packets of this size are assumed truncated. Size allows for some legacy packet bugs and includes overhead.
    
    See Also:
    
    Constant Field Values
  - MAX_PAYLOAD_TYPE
```
public static final int MAX_PAYLOAD_TYPE
```
    See Also:
    
    Constant Field Values
  - PAYLOAD_TYPE_DATA
```
public static final int PAYLOAD_TYPE_DATA
```
    See Also:
    
    Constant Field Values
  - PAYLOAD_TYPE_RELAY_INTRO
```
public static final int PAYLOAD_TYPE_RELAY_INTRO
```
    See Also:
    
    Constant Field Values
  - PAYLOAD_TYPE_RELAY_REQUEST
```
public static final int PAYLOAD_TYPE_RELAY_REQUEST
```
    See Also:
    
    Constant Field Values
  - PAYLOAD_TYPE_RELAY_RESPONSE
```
public static final int PAYLOAD_TYPE_RELAY_RESPONSE
```
    See Also:
    
    Constant Field Values
  - PAYLOAD_TYPE_SESSION_CONFIRMED
```
public static final int PAYLOAD_TYPE_SESSION_CONFIRMED
```
    See Also:
    
    Constant Field Values
  - PAYLOAD_TYPE_SESSION_CREATED
```
public static final int PAYLOAD_TYPE_SESSION_CREATED
```
    See Also:
    
    Constant Field Values
  - PAYLOAD_TYPE_SESSION_DESTROY
```
public static final int PAYLOAD_TYPE_SESSION_DESTROY
```
    See Also:
    
    Constant Field Values
  - PAYLOAD_TYPE_SESSION_REQUEST
```
public static final int PAYLOAD_TYPE_SESSION_REQUEST
```
    See Also:
    
    Constant Field Values
  - PAYLOAD_TYPE_TEST
```
public static final int PAYLOAD_TYPE_TEST
```
    See Also:
    
    Constant Field Values
- Method Detail
  - acquire
```
public static UDPPacket acquire(RouterContext ctx,
                                boolean inbound)
```
    Acquires a UDPPacket instance, either from the cache or by creating a new instance. Initializes the packet for use.
    
    Parameters:
    
    ctx - RouterContext for timing and logging
    
    inbound - true if this packet is inbound, false if outbound (currently unused)
    
    Returns:
    
    initialized UDPPacket instance
  - clearCache
```
public static void clearCache()
```
    Clears the internal packet cache if caching is enabled. Useful to free resources, e.g. on shutdown or restart.
  - drop
```
public void drop()
```
    Convenience method to release the packet.
    
    Specified by:
    
    drop in interface CDQEntry
  - getBandwidthRequest
```
public FIFOBandwidthLimiter.Request getBandwidthRequest()
```
    Returns the current bandwidth request associated with this packet.
    
    Returns:
    
    bandwidth request object, or null if none exists
  - getBegin
```
public long getBegin()
```
    Gets the packet initialization timestamp in milliseconds.
    
    Returns:
    
    time in ms when packet was initialized
  - getEnqueueTime
```
public long getEnqueueTime()
```
    Gets the time the packet was enqueued.
    
    Specified by:
    
    getEnqueueTime in interface CDQEntry
    
    Returns:
    
    enqueue timestamp in milliseconds
  - getFragmentCount
```
int getFragmentCount()
```
  - getLifetime
```
public long getLifetime()
```
    Returns how long this packet has existed since initialization.
    
    Returns:
    
    lifetime in milliseconds
  - getMarkedType
```
public int getMarkedType()
```
    Gets the currently marked type of the packet.
    
    Returns:
    
    mark type integer or -1 if none set
  - getMessageType
```
int getMessageType()
```
  - getPacket
```
public DatagramPacket getPacket()
```
    Gets the underlying DatagramPacket.
    
    Returns:
    
    datagram packet instance
    
    Throws:
    
    IllegalStateException - if the packet has been released
  - getPriority
```
public int getPriority()
```
    Gets the packet priority.
    
    Specified by:
    
    getPriority in interface PQEntry
    
    Returns:
    
    packet priority as integer
  - getRemoteHost
```
RemoteHostId getRemoteHost()
```
    Lazily obtains the RemoteHostId representing the sender's address and port. This is initialized once per packet and cached thereafter.
    
    Returns:
    
    remote host identifier or null if address unavailable
  - getSeqNum
```
public long getSeqNum()
```
    Gets the packet sequence number.
    
    Specified by:
    
    getSeqNum in interface PQEntry
    
    Returns:
    
    sequence number
  - getTimeSinceReceived
```
long getTimeSinceReceived()
```
    Returns the amount of time elapsed since the packet was received.
    
    Returns:
    
    milliseconds since received, or 0 if never received
  - markType
```
public void markType(int type)
```
    Marks the packet with a custom type for internal identification.
    
    Parameters:
    
    type - integer representing a mark type
  - payloadTypeToString
```
public static String payloadTypeToString(int type)
```
    Converts payload type integer constant to human-readable string.
    
    Parameters:
    
    type - the payload type constant
    
    Returns:
    
    descriptive string of payload type
  - received
```
void received()
```
    Marks the packet as received, recording the current time.
  - reduceCacheSize
```
public static void reduceCacheSize()
```
    Reduces cache size under memory pressure.
  - release
```
public void release()
```
    Releases this packet back to the object cache and aborts any outstanding bandwidth request. Safe to call multiple times. After release, accessing the packet will log errors.
  - requestOutboundBandwidth
```
public void requestOutboundBandwidth()
```
    Requests outbound bandwidth for sending this packet. The bandwidth request is tracked and can be aborted if the packet is released early.
  - resetBegin
```
public void resetBegin()
```
    Resets the initialization timestamp to current time.
  - setEnqueueTime
```
public void setEnqueueTime(long now)
```
    Sets the enqueue time timestamp, indicating when the packet was queued for processing.
    
    Specified by:
    
    setEnqueueTime in interface CDQEntry
    
    Parameters:
    
    now - enqueue time in milliseconds
  - setFragmentCount
```
void setFragmentCount(int count)
```
  - setMessageType
```
void setMessageType(int type)
```
  - setPriority
```
public void setPriority(int pri)
```
    Sets the packet priority.
    
    Parameters:
    
    pri - priority level to assign
  - setSeqNum
```
public void setSeqNum(long num)
```
    Sets the packet sequence number.
    
    Specified by:
    
    setSeqNum in interface PQEntry
    
    Parameters:
    
    num - sequence number to set
  - toString
```
public String toString()
```
    Returns a detailed string representation of this packet, including address, size, priority, message and mark types, fragment counts, and timing information. For logging and debugging purposes.
    
    Overrides:
    
    toString in class Object

Class UDPPacket

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

IV_SIZE

MAC_SIZE

MAX_PACKET_SIZE

MAX_PAYLOAD_TYPE

PAYLOAD_TYPE_DATA

PAYLOAD_TYPE_RELAY_INTRO

PAYLOAD_TYPE_RELAY_REQUEST

PAYLOAD_TYPE_RELAY_RESPONSE

PAYLOAD_TYPE_SESSION_CONFIRMED

PAYLOAD_TYPE_SESSION_CREATED

PAYLOAD_TYPE_SESSION_DESTROY

PAYLOAD_TYPE_SESSION_REQUEST

PAYLOAD_TYPE_TEST

Method Detail

acquire

clearCache

drop

getBandwidthRequest

getBegin

getEnqueueTime

getFragmentCount

getLifetime

getMarkedType

getMessageType

getPacket

getPriority

getRemoteHost

getSeqNum

getTimeSinceReceived

markType

payloadTypeToString

received

reduceCacheSize

release

requestOutboundBandwidth

resetBegin

setEnqueueTime

setFragmentCount

setMessageType

setPriority

setSeqNum

toString