net.i2p.router.transport

Class FIFOBandwidthLimiter

java.lang.Object

net.i2p.router.transport.FIFOBandwidthLimiter

public class FIFOBandwidthLimiter
extends Object

FIFO-based bandwidth limiter for managing inbound and outbound traffic. This class provides bandwidth management using First-In-First-Out queues for both inbound and outbound traffic. It implements token bucket algorithm to control data rates and prevent burst traffic patterns. Core Features:

• FIFO request queuing for fair bandwidth allocation
• Token bucket rate limiting
• Separate inbound and outbound management
• Configurable bandwidth limits and refill rates
• Thread-safe operations with atomic counters
• Request satisfaction and partial fulfillment handling

Concurrency Strategy:

• Java 5: Used synchronized ArrayList with head/tail access
• Java 6+: Uses LinkedBlockingDeque for lock-free operations
• Request polling from queue head for efficiency
• Partial request satisfaction with push-back mechanism

Algorithm:

• Token refill at fixed intervals
• Request processing when tokens available
• Burst prevention through token depletion
• Priority-based request handling

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	FIFOBandwidthLimiter.CompleteListener Listener for bandwidth request completion events.
static interface	FIFOBandwidthLimiter.Request A bandwidth request, either inbound or outbound.

Constructor Summary

Constructors

Constructor and Description
FIFOBandwidthLimiter(RouterContext context)

Method Summary

Modifier and Type	Method and Description
int	getCurrentParticipatingBandwidth() Out bandwidth.
int	getInboundBurstBytes()
int	getInboundBurstKBytesPerSecond() The configured maximum, not the current rate.
int	getInboundKBytesPerSecond() The configured maximum, not the current rate.
int	getMaxShareBandwidth() In Bytes per second
int	getOutboundBurstBytes()
int	getOutboundBurstKBytesPerSecond() The configured maximum, not the current rate.
int	getOutboundKBytesPerSecond() The configured maximum, not the current rate.
float	getReceiveBps()
float	getReceiveBps15s()
float	getSendBps()
float	getSendBps15s()
(package private) StringBuilder	getStatus()
long	getTotalAllocatedInboundBytes()
long	getTotalAllocatedOutboundBytes()
long	now()
(package private) void	refillBandwidthQueues(List<FIFOBandwidthLimiter.Request> buf, long bytesInbound, long bytesOutbound, long maxBurstIn, long maxBurstOut) More bytes are available - add them to the queue and satisfy any requests we can
void	reinitialize()
FIFOBandwidthLimiter.Request	requestInbound(int bytesIn, String purpose) Request some bytes.
FIFOBandwidthLimiter.Request	requestOutbound(int bytesOut, int priority, String purpose) Request some bytes.
boolean	sentParticipatingMessage(int size, float factor) We intend to send traffic for a participating tunnel with the given size and adjustment factor.
(package private) void	setInboundBurstBytes(int bytes)
(package private) void	setInboundBurstKBps(int kbytesPerSecond)
(package private) void	setOutboundBurstBytes(int bytes)
(package private) void	setOutboundBurstKBps(int kbytesPerSecond)
void	shutdown()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FIFOBandwidthLimiter

public FIFOBandwidthLimiter(RouterContext context)

Method Detail

getCurrentParticipatingBandwidth

public int getCurrentParticipatingBandwidth()

Out bandwidth. Actual bandwidth, not smoothed, not bucketed.

Returns:

Bps in recent period (a few seconds)

getInboundBurstBytes

public int getInboundBurstBytes()

getInboundBurstKBytesPerSecond

public int getInboundBurstKBytesPerSecond()

The configured maximum, not the current rate. In binary K, i.e. rate / 1024.

getInboundKBytesPerSecond

public int getInboundKBytesPerSecond()

The configured maximum, not the current rate. In binary K, i.e. rate / 1024.

getMaxShareBandwidth

public int getMaxShareBandwidth()

In Bytes per second

getOutboundBurstBytes

public int getOutboundBurstBytes()

getOutboundBurstKBytesPerSecond

public int getOutboundBurstKBytesPerSecond()

The configured maximum, not the current rate. In binary K, i.e. rate / 1024.

getOutboundKBytesPerSecond

public int getOutboundKBytesPerSecond()

The configured maximum, not the current rate. In binary K, i.e. rate / 1024.

getReceiveBps

public float getReceiveBps()

Returns:

smoothed one second rate

getReceiveBps15s

public float getReceiveBps15s()

Returns:

smoothed 15 second rate

getSendBps

public float getSendBps()

Returns:

smoothed one second rate

getSendBps15s

public float getSendBps15s()

Returns:

smoothed 15 second rate

getStatus

StringBuilder getStatus()

getTotalAllocatedInboundBytes

public long getTotalAllocatedInboundBytes()

getTotalAllocatedOutboundBytes

public long getTotalAllocatedOutboundBytes()

now

public long now()

refillBandwidthQueues

final void refillBandwidthQueues(List<FIFOBandwidthLimiter.Request> buf,
                                 long bytesInbound,
                                 long bytesOutbound,
                                 long maxBurstIn,
                                 long maxBurstOut)

More bytes are available - add them to the queue and satisfy any requests we can

Parameters:

buf - contains satisfied outbound requests, really just to avoid object thrash, not really used

maxBurstIn - allow up to this many bytes in from the burst section for this time period (may be negative)

maxBurstOut - allow up to this many bytes in from the burst section for this time period (may be negative)

reinitialize

public void reinitialize()

requestInbound

public FIFOBandwidthLimiter.Request requestInbound(int bytesIn,
                                                   String purpose)

Request some bytes. Does not block.

requestOutbound

public FIFOBandwidthLimiter.Request requestOutbound(int bytesOut,
                                                    int priority,
                                                    String purpose)

Request some bytes. Does not block.

sentParticipatingMessage

public boolean sentParticipatingMessage(int size,
                                        float factor)

We intend to send traffic for a participating tunnel with the given size and adjustment factor. Returns true if the message can be sent within the current share bandwidth limits, or false if it should be dropped.

Parameters:

size - bytes

factor - multiplier of size for the drop calculation, 1 for no adjustment

Returns:

true for accepted, false for drop

setInboundBurstBytes

void setInboundBurstBytes(int bytes)

setInboundBurstKBps

void setInboundBurstKBps(int kbytesPerSecond)

setOutboundBurstBytes

void setOutboundBurstBytes(int bytes)

setOutboundBurstKBps

void setOutboundBurstKBps(int kbytesPerSecond)

shutdown

public void shutdown()