sing-box/transport/hysteria/brutal.go
2023-07-31 09:49:07 +08:00

150 lines
3.7 KiB
Go

package hysteria
import (
"time"
"github.com/sagernet/quic-go/congestion"
)
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(now time.Time) bool {
return b.pacer.Budget(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
}