Package io.github.mahmoudimus.quic.connection

Class PendingAcks

java.lang.Object
io.github.mahmoudimus.quic.connection.PendingAcks
public final class PendingAcks extends Object
The packets of one space waiting to be acknowledged, and when an ACK must go out (RFC 9000 section 13.2): after more than ack_eliciting_threshold ack-eliciting packets (one, by default, so every second one is acknowledged at once), on reordering, or once max_ack_delay has passed since the first unacknowledged ack-eliciting packet.

At most 64 ranges are kept, so an ACK frame always fits a minimum-size packet; the oldest are dropped first.

Threads. Not thread-safe; owned by one connection.

  • Field Details

    • MAX_ACK_BLOCKS

      public static final int MAX_ACK_BLOCKS
      The most ACK ranges kept.
      See Also:

  • Constructor Details

    • PendingAcks

      public PendingAcks()
      Nothing to acknowledge.

  • Method Details

    • setAckFrequencyParams

      public void setAckFrequencyParams(Frame.AckFrequency frame)
      Applies an ACK_FREQUENCY frame's thresholds.
      Parameters:
      frame - the frame

    • setImmediateAckRequired

      public void setImmediateAckRequired()
      Requires an immediate ACK, as for an IMMEDIATE_ACK frame or an ECN-CE mark.

    • onMaxAckDelayTimeout

      public void onMaxAckDelayTimeout()
      Handles the expiry of the Timer.MAX_ACK_DELAY timer.

    • maxAckDelayTimeout

      public long maxAckDelayTimeout(long maxAckDelay)
      When an ACK is due because max_ack_delay expires.
      Parameters:
      maxAckDelay - this endpoint's max_ack_delay, in nanoseconds
      Returns:
      the deadline, or NanoClock.NONE if no ack-eliciting packet is unacknowledged

    • canSend

      public boolean canSend()
      Whether an ACK must be sent, even in a packet of its own.
      Returns:
      true if one is required and there is something to acknowledge

    • canSendWithOtherFrames

      public boolean canSendWithOtherFrames()
      Whether an ACK can ride along in a packet sent for other reasons.
      Returns:
      true if there is something to acknowledge

    • ackDelay

      public long ackDelay(long now)
      The time since the largest packet arrived, for the ACK Delay field.
      Parameters:
      now - the current time
      Returns:
      nanoseconds, zero if nothing was received

    • packetReceived

      public boolean packetReceived(long now, long packetNumber, boolean ackEliciting, Dedup dedup)
      Handles a received packet's ACK requirements; call insertOne(long, long) for it too.
      Parameters:
      now - the current time
      packetNumber - the packet number
      ackEliciting - whether the packet is ack-eliciting
      dedup - the space's duplicate detector, which already holds the packet
      Returns:
      true if the Timer.MAX_ACK_DELAY timer should be armed

    • acksSent

      public void acksSent()
      Records that an ACK was sent, suppressing more until new ack-eliciting packets arrive. The ACK is assumed to have covered everything; anything it missed is acknowledged later.

    • insertOne

      public void insertOne(long packet, long now)
      Adds a packet to acknowledge.
      Parameters:
      packet - the packet number
      now - when it arrived

    • subtractBelow

      public void subtractBelow(long max)
      Stops acknowledging packets numbered at or below max: the peer received an ACK of them.
      Parameters:
      max - the largest packet number to drop

    • ranges

      public RangeSet ranges()
      The packet numbers to acknowledge.
      Returns:
      a live view; do not modify

    • maybeAckNonEliciting

      public void maybeAckNonEliciting()
      Requires an ACK in the next packet if many non-ack-eliciting packets went unacknowledged, which helps a peer that sends nothing ack-eliciting detect loss. Call it just before building a packet that will be sent anyway.

    • ackFrame

      public Frame.Ack ackFrame(long now, long ackDelayExponent, Frame.EcnCounts ecn)
      Builds the ACK frame for the pending ranges.
      Parameters:
      now - the current time
      ackDelayExponent - this endpoint's ack_delay_exponent
      ecn - the ECN counts to report, or null
      Returns:
      the frame, or null if there is nothing to acknowledge