chore: embed hysteria, clean irrelevant codes, code from https://github.com/HyNetwork/hysteria

transport/hysteria/congestion/brutal.go

@@ -0,0 +1,145 @@
+package congestion
+
+import (
+	"github.com/lucas-clemente/quic-go/congestion"
+	"time"
+)
+
+const (
+	initMaxDatagramSize = 1252
+
+	pktInfoSlotCount = 4
+	minSampleCount   = 50
+	minAckRate       = 0.8
+)
+
+type BrutalSender struct {
+	rttStats        congestion.RTTStatsProvider
+	bps             congestion.ByteCount
+	maxDatagramSize congestion.ByteCount
+	pacer           *pacer
+
+	pktInfoSlots [pktInfoSlotCount]pktInfo
+	ackRate      float64
+}
+
+type pktInfo struct {
+	Timestamp int64
+	AckCount  uint64
+	LossCount uint64
+}
+
+func NewBrutalSender(bps congestion.ByteCount) *BrutalSender {
+	bs := &BrutalSender{
+		bps:             bps,
+		maxDatagramSize: initMaxDatagramSize,
+		ackRate:         1,
+	}
+	bs.pacer = newPacer(func() congestion.ByteCount {
+		return congestion.ByteCount(float64(bs.bps) / bs.ackRate)
+	})
+	return bs
+}
+
+func (b *BrutalSender) SetRTTStatsProvider(rttStats congestion.RTTStatsProvider) {
+	b.rttStats = rttStats
+}
+
+func (b *BrutalSender) TimeUntilSend(bytesInFlight congestion.ByteCount) time.Time {
+	return b.pacer.TimeUntilSend()
+}
+
+func (b *BrutalSender) HasPacingBudget() bool {
+	return b.pacer.Budget(time.Now()) >= b.maxDatagramSize
+}
+
+func (b *BrutalSender) CanSend(bytesInFlight congestion.ByteCount) bool {
+	return bytesInFlight < b.GetCongestionWindow()
+}
+
+func (b *BrutalSender) GetCongestionWindow() congestion.ByteCount {
+	rtt := maxDuration(b.rttStats.LatestRTT(), b.rttStats.SmoothedRTT())
+	if rtt <= 0 {
+		return 10240
+	}
+	return congestion.ByteCount(float64(b.bps) * rtt.Seconds() * 1.5 / b.ackRate)
+}
+
+func (b *BrutalSender) OnPacketSent(sentTime time.Time, bytesInFlight congestion.ByteCount,
+	packetNumber congestion.PacketNumber, bytes congestion.ByteCount, isRetransmittable bool) {
+	b.pacer.SentPacket(sentTime, bytes)
+}
+
+func (b *BrutalSender) OnPacketAcked(number congestion.PacketNumber, ackedBytes congestion.ByteCount,
+	priorInFlight congestion.ByteCount, eventTime time.Time) {
+	currentTimestamp := eventTime.Unix()
+	slot := currentTimestamp % pktInfoSlotCount
+	if b.pktInfoSlots[slot].Timestamp == currentTimestamp {
+		b.pktInfoSlots[slot].AckCount++
+	} else {
+		// uninitialized slot or too old, reset
+		b.pktInfoSlots[slot].Timestamp = currentTimestamp
+		b.pktInfoSlots[slot].AckCount = 1
+		b.pktInfoSlots[slot].LossCount = 0
+	}
+	b.updateAckRate(currentTimestamp)
+}
+
+func (b *BrutalSender) OnPacketLost(number congestion.PacketNumber, lostBytes congestion.ByteCount,
+	priorInFlight congestion.ByteCount) {
+	currentTimestamp := time.Now().Unix()
+	slot := currentTimestamp % pktInfoSlotCount
+	if b.pktInfoSlots[slot].Timestamp == currentTimestamp {
+		b.pktInfoSlots[slot].LossCount++
+	} else {
+		// uninitialized slot or too old, reset
+		b.pktInfoSlots[slot].Timestamp = currentTimestamp
+		b.pktInfoSlots[slot].AckCount = 0
+		b.pktInfoSlots[slot].LossCount = 1
+	}
+	b.updateAckRate(currentTimestamp)
+}
+
+func (b *BrutalSender) SetMaxDatagramSize(size congestion.ByteCount) {
+	b.maxDatagramSize = size
+	b.pacer.SetMaxDatagramSize(size)
+}
+
+func (b *BrutalSender) updateAckRate(currentTimestamp int64) {
+	minTimestamp := currentTimestamp - pktInfoSlotCount
+	var ackCount, lossCount uint64
+	for _, info := range b.pktInfoSlots {
+		if info.Timestamp < minTimestamp {
+			continue
+		}
+		ackCount += info.AckCount
+		lossCount += info.LossCount
+	}
+	if ackCount+lossCount < minSampleCount {
+		b.ackRate = 1
+	}
+	rate := float64(ackCount) / float64(ackCount+lossCount)
+	if rate < minAckRate {
+		b.ackRate = minAckRate
+	}
+	b.ackRate = rate
+}
+
+func (b *BrutalSender) InSlowStart() bool {
+	return false
+}
+
+func (b *BrutalSender) InRecovery() bool {
+	return false
+}
+
+func (b *BrutalSender) MaybeExitSlowStart() {}
+
+func (b *BrutalSender) OnRetransmissionTimeout(packetsRetransmitted bool) {}
+
+func maxDuration(a, b time.Duration) time.Duration {
+	if a > b {
+		return a
+	}
+	return b
+}