remove unused duplicate packet detection in the ackHandler

ackhandler/received_packet_handler_test.go

@@ -59,17 +59,6 @@ var _ = Describe("receivedPacketHandler", func() {
 			Expect(handler.largestObservedReceivedTime).To(Equal(timestamp))
 		})
 
-		It("doesn't store more than MaxTrackedReceivedPackets packets", func() {
-			err := handler.ReceivedPacket(1, true)
-			Expect(err).ToNot(HaveOccurred())
-			for i := protocol.PacketNumber(3); i < 3+protocol.MaxTrackedReceivedPackets-1; i++ {
-				err := handler.ReceivedPacket(protocol.PacketNumber(i), true)
-				Expect(err).ToNot(HaveOccurred())
-			}
-			err = handler.ReceivedPacket(protocol.PacketNumber(protocol.MaxTrackedReceivedPackets)+10, true)
-			Expect(err).To(MatchError(errTooManyOutstandingReceivedPackets))
-		})
-
 		It("passes on errors from receivedPacketHistory", func() {
 			var err error
 			for i := protocol.PacketNumber(0); i < 5*protocol.MaxTrackedReceivedAckRanges; i++ {

ackhandler/received_packet_history.go

@@ -12,21 +12,15 @@ import (
 type receivedPacketHistory struct {
 	ranges *utils.PacketIntervalList
 
-	// the map is used as a replacement for a set here. The bool is always supposed to be set to true
-	receivedPacketNumbers         map[protocol.PacketNumber]bool
 	lowestInReceivedPacketNumbers protocol.PacketNumber
 }
 
-var (
+var errTooManyOutstandingReceivedAckRanges = qerr.Error(qerr.TooManyOutstandingReceivedPackets, "Too many outstanding received ACK ranges")
-	errTooManyOutstandingReceivedAckRanges = qerr.Error(qerr.TooManyOutstandingReceivedPackets, "Too many outstanding received ACK ranges")
-	errTooManyOutstandingReceivedPackets   = qerr.Error(qerr.TooManyOutstandingReceivedPackets, "Too many outstanding received packets")
-)
 
 // newReceivedPacketHistory creates a new received packet history
 func newReceivedPacketHistory() *receivedPacketHistory {
 	return &receivedPacketHistory{
 		ranges: utils.NewPacketIntervalList(),
-		receivedPacketNumbers: make(map[protocol.PacketNumber]bool),
 	}
 }
 
@@ -36,12 +30,6 @@ func (h *receivedPacketHistory) ReceivedPacket(p protocol.PacketNumber) error {
 		return errTooManyOutstandingReceivedAckRanges
 	}
 
-	if len(h.receivedPacketNumbers) >= protocol.MaxTrackedReceivedPackets {
-		return errTooManyOutstandingReceivedPackets
-	}
-
-	h.receivedPacketNumbers[p] = true
-
 	if h.ranges.Len() == 0 {
 		h.ranges.PushBack(utils.PacketInterval{Start: p, End: p})
 		return nil
@@ -95,14 +83,8 @@ func (h *receivedPacketHistory) DeleteUpTo(p protocol.PacketNumber) {
 		nextEl = el.Next()
 
 		if p >= el.Value.Start && p < el.Value.End {
-			for i := el.Value.Start; i <= p; i++ { // adjust start value of a range
-				delete(h.receivedPacketNumbers, i)
-			}
 			el.Value.Start = p + 1
 		} else if el.Value.End <= p { // delete a whole range
-			for i := el.Value.Start; i <= el.Value.End; i++ {
-				delete(h.receivedPacketNumbers, i)
-			}
 			h.ranges.Remove(el)
 		} else { // no ranges affected. Nothing to do
 			return
@@ -110,17 +92,6 @@ func (h *receivedPacketHistory) DeleteUpTo(p protocol.PacketNumber) {
 	}
 }
 
-// IsDuplicate determines if a packet should be regarded as a duplicate packet
-// note that after receiving a StopWaitingFrame, all packets below the LeastUnacked should be regarded as duplicates, even if the packet was just delayed
-func (h *receivedPacketHistory) IsDuplicate(p protocol.PacketNumber) bool {
-	if p < h.lowestInReceivedPacketNumbers {
-		return true
-	}
-
-	_, ok := h.receivedPacketNumbers[p]
-	return ok
-}
-
 // GetAckRanges gets a slice of all AckRanges that can be used in an AckFrame
 func (h *receivedPacketHistory) GetAckRanges() []wire.AckRange {
 	if h.ranges.Len() == 0 {

ackhandler/received_packet_history_test.go

@@ -17,51 +17,17 @@ var _ = Describe("receivedPacketHistory", func() {
 		hist = newReceivedPacketHistory()
 	})
 
-	// check if the ranges PacketIntervalList contains exactly the same packet number as the receivedPacketNumbers
-	historiesConsistent := func() bool {
-		// check if a packet number is contained in any of the ranges
-		containedInRanges := func(p protocol.PacketNumber) bool {
-			for el := hist.ranges.Front(); el != nil; el = el.Next() {
-				if p >= el.Value.Start && p <= el.Value.End {
-					return true
-				}
-			}
-			return false
-		}
-
-		// first check if all packets contained in the ranges are present in the map
-		for el := hist.ranges.Front(); el != nil; el = el.Next() {
-			for i := el.Value.Start; i <= el.Value.Start; i++ {
-				_, ok := hist.receivedPacketNumbers[i]
-				if !ok {
-					return false
-				}
-			}
-		}
-
-		// then check if all packets in the map are contained in any of the ranges
-		for i := range hist.receivedPacketNumbers {
-			if !containedInRanges(i) {
-				return false
-			}
-		}
-
-		return true
-	}
-
 	Context("ranges", func() {
 		It("adds the first packet", func() {
 			hist.ReceivedPacket(4)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 4}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("doesn't care about duplicate packets", func() {
 			hist.ReceivedPacket(4)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 4}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("adds a few consecutive packets", func() {
@@ -70,7 +36,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			hist.ReceivedPacket(6)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 6}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("doesn't care about a duplicate packet contained in an existing range", func() {
@@ -80,7 +45,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			hist.ReceivedPacket(5)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 6}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("extends a range at the front", func() {
@@ -88,7 +52,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			hist.ReceivedPacket(3)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 3, End: 4}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("creates a new range when a packet is lost", func() {
@@ -97,7 +60,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			Expect(hist.ranges.Len()).To(Equal(2))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 4}))
 			Expect(hist.ranges.Back().Value).To(Equal(utils.PacketInterval{Start: 6, End: 6}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("creates a new range in between two ranges", func() {
@@ -109,7 +71,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 4}))
 			Expect(hist.ranges.Front().Next().Value).To(Equal(utils.PacketInterval{Start: 7, End: 7}))
 			Expect(hist.ranges.Back().Value).To(Equal(utils.PacketInterval{Start: 10, End: 10}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("creates a new range before an existing range for a belated packet", func() {
@@ -118,7 +79,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			Expect(hist.ranges.Len()).To(Equal(2))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 4}))
 			Expect(hist.ranges.Back().Value).To(Equal(utils.PacketInterval{Start: 6, End: 6}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("extends a previous range at the end", func() {
@@ -128,7 +88,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			Expect(hist.ranges.Len()).To(Equal(2))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 5}))
 			Expect(hist.ranges.Back().Value).To(Equal(utils.PacketInterval{Start: 7, End: 7}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("extends a range at the front", func() {
@@ -138,7 +97,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			Expect(hist.ranges.Len()).To(Equal(2))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 4}))
 			Expect(hist.ranges.Back().Value).To(Equal(utils.PacketInterval{Start: 6, End: 7}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("closes a range", func() {
@@ -148,7 +106,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			hist.ReceivedPacket(5)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 6}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("closes a range in the middle", func() {
@@ -162,7 +119,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 1, End: 1}))
 			Expect(hist.ranges.Front().Next().Value).To(Equal(utils.PacketInterval{Start: 4, End: 6}))
 			Expect(hist.ranges.Back().Value).To(Equal(utils.PacketInterval{Start: 10, End: 10}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 	})
 
@@ -170,7 +126,6 @@ var _ = Describe("receivedPacketHistory", func() {
 		It("does nothing when the history is empty", func() {
 			hist.DeleteUpTo(5)
 			Expect(hist.ranges.Len()).To(BeZero())
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("deletes a range", func() {
@@ -180,7 +135,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			hist.DeleteUpTo(5)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 10, End: 10}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("deletes multiple ranges", func() {
@@ -190,7 +144,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			hist.DeleteUpTo(8)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 10, End: 10}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("adjusts a range, if packets are delete from an existing range", func() {
@@ -202,7 +155,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			hist.DeleteUpTo(4)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 5, End: 7}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("adjusts a range, if only one packet remains in the range", func() {
@@ -213,7 +165,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			Expect(hist.ranges.Len()).To(Equal(2))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 5, End: 5}))
 			Expect(hist.ranges.Back().Value).To(Equal(utils.PacketInterval{Start: 10, End: 10}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		It("keeps a one-packet range, if deleting up to the packet directly below", func() {
@@ -221,7 +172,6 @@ var _ = Describe("receivedPacketHistory", func() {
 			hist.DeleteUpTo(3)
 			Expect(hist.ranges.Len()).To(Equal(1))
 			Expect(hist.ranges.Front().Value).To(Equal(utils.PacketInterval{Start: 4, End: 4}))
-			Expect(historiesConsistent()).To(BeTrue())
 		})
 
 		Context("DoS protection", func() {
@@ -232,18 +182,6 @@ var _ = Describe("receivedPacketHistory", func() {
 				}
 				err := hist.ReceivedPacket(2*protocol.MaxTrackedReceivedAckRanges + 2)
 				Expect(err).To(MatchError(errTooManyOutstandingReceivedAckRanges))
-				Expect(historiesConsistent()).To(BeTrue())
-			})
-
-			It("doesn't store more than MaxTrackedReceivedPackets packets", func() {
-				err := hist.ReceivedPacket(1)
-				Expect(err).ToNot(HaveOccurred())
-				for i := protocol.PacketNumber(3); i < 3+protocol.MaxTrackedReceivedPackets-1; i++ {
-					err := hist.ReceivedPacket(protocol.PacketNumber(i))
-					Expect(err).ToNot(HaveOccurred())
-				}
-				err = hist.ReceivedPacket(protocol.PacketNumber(protocol.MaxTrackedReceivedPackets) + 10)
-				Expect(err).To(MatchError(errTooManyOutstandingReceivedPackets))
 			})
 
 			It("doesn't consider already deleted ranges for MaxTrackedReceivedAckRanges", func() {
@@ -256,38 +194,10 @@ var _ = Describe("receivedPacketHistory", func() {
 				hist.DeleteUpTo(protocol.MaxTrackedReceivedAckRanges) // deletes about half of the ranges
 				err = hist.ReceivedPacket(2*protocol.MaxTrackedReceivedAckRanges + 4)
 				Expect(err).ToNot(HaveOccurred())
-				Expect(historiesConsistent()).To(BeTrue())
 			})
 		})
 	})
 
-	Context("duplicate packet detection", func() {
-		It("detects duplicates for existing ranges", func() {
-			hist.ReceivedPacket(2)
-			hist.ReceivedPacket(4)
-			hist.ReceivedPacket(5)
-			Expect(hist.IsDuplicate(1)).To(BeFalse())
-			Expect(hist.IsDuplicate(2)).To(BeTrue())
-			Expect(hist.IsDuplicate(3)).To(BeFalse())
-			Expect(hist.IsDuplicate(4)).To(BeTrue())
-			Expect(hist.IsDuplicate(5)).To(BeTrue())
-			Expect(hist.IsDuplicate(6)).To(BeFalse())
-		})
-
-		It("detects duplicates after a range has been deleted", func() {
-			hist.ReceivedPacket(2)
-			hist.ReceivedPacket(3)
-			hist.ReceivedPacket(6)
-			hist.DeleteUpTo(4)
-			for i := 1; i < 5; i++ {
-				Expect(hist.IsDuplicate(protocol.PacketNumber(i))).To(BeTrue())
-			}
-			Expect(hist.IsDuplicate(5)).To(BeFalse())
-			Expect(hist.IsDuplicate(6)).To(BeTrue())
-			Expect(hist.IsDuplicate(7)).To(BeFalse())
-		})
-	})
-
 	Context("ACK range export", func() {
 		It("returns nil if there are no ranges", func() {
 			Expect(hist.GetAckRanges()).To(BeNil())

internal/protocol/server_parameters.go

@@ -87,9 +87,6 @@ const STKExpiryTime = 24 * time.Hour
 // MaxTrackedSentPackets is maximum number of sent packets saved for either later retransmission or entropy calculation
 const MaxTrackedSentPackets = 2 * DefaultMaxCongestionWindow
 
-// MaxTrackedReceivedPackets is the maximum number of received packets saved for doing the entropy calculations
-const MaxTrackedReceivedPackets = 2 * DefaultMaxCongestionWindow
-
 // MaxTrackedReceivedAckRanges is the maximum number of ACK ranges tracked
 const MaxTrackedReceivedAckRanges = DefaultMaxCongestionWindow