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received_packet_tracker_test.go
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received_packet_tracker_test.go
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package ackhandler
import (
"time"
"github.com/lucas-clemente/quic-go/internal/protocol"
"github.com/lucas-clemente/quic-go/internal/utils"
"github.com/lucas-clemente/quic-go/internal/wire"
. "github.com/onsi/ginkgo"
. "github.com/onsi/gomega"
)
var _ = Describe("Received Packet Tracker", func() {
var (
tracker *receivedPacketTracker
rttStats *utils.RTTStats
)
BeforeEach(func() {
rttStats = &utils.RTTStats{}
tracker = newReceivedPacketTracker(rttStats, utils.DefaultLogger, protocol.VersionWhatever)
})
Context("accepting packets", func() {
It("saves the time when each packet arrived", func() {
tracker.ReceivedPacket(protocol.PacketNumber(3), time.Now(), true)
Expect(tracker.largestObservedReceivedTime).To(BeTemporally("~", time.Now(), 10*time.Millisecond))
})
It("updates the largestObserved and the largestObservedReceivedTime", func() {
now := time.Now()
tracker.largestObserved = 3
tracker.largestObservedReceivedTime = now.Add(-1 * time.Second)
tracker.ReceivedPacket(5, now, true)
Expect(tracker.largestObserved).To(Equal(protocol.PacketNumber(5)))
Expect(tracker.largestObservedReceivedTime).To(Equal(now))
})
It("doesn't update the largestObserved and the largestObservedReceivedTime for a belated packet", func() {
now := time.Now()
timestamp := now.Add(-1 * time.Second)
tracker.largestObserved = 5
tracker.largestObservedReceivedTime = timestamp
tracker.ReceivedPacket(4, now, true)
Expect(tracker.largestObserved).To(Equal(protocol.PacketNumber(5)))
Expect(tracker.largestObservedReceivedTime).To(Equal(timestamp))
})
})
Context("ACKs", func() {
Context("queueing ACKs", func() {
receiveAndAck10Packets := func() {
for i := 1; i <= 10; i++ {
tracker.ReceivedPacket(protocol.PacketNumber(i), time.Time{}, true)
}
Expect(tracker.GetAckFrame(true)).ToNot(BeNil())
Expect(tracker.ackQueued).To(BeFalse())
}
It("always queues an ACK for the first packet", func() {
tracker.ReceivedPacket(1, time.Now(), true)
Expect(tracker.ackQueued).To(BeTrue())
Expect(tracker.GetAlarmTimeout()).To(BeZero())
Expect(tracker.GetAckFrame(true).DelayTime).To(BeNumerically("~", 0, time.Second))
})
It("works with packet number 0", func() {
tracker.ReceivedPacket(0, time.Now(), true)
Expect(tracker.ackQueued).To(BeTrue())
Expect(tracker.GetAlarmTimeout()).To(BeZero())
Expect(tracker.GetAckFrame(true).DelayTime).To(BeNumerically("~", 0, time.Second))
})
It("queues an ACK for every second ack-eliciting packet", func() {
receiveAndAck10Packets()
p := protocol.PacketNumber(11)
for i := 0; i <= 20; i++ {
tracker.ReceivedPacket(p, time.Time{}, true)
Expect(tracker.ackQueued).To(BeFalse())
p++
tracker.ReceivedPacket(p, time.Time{}, true)
Expect(tracker.ackQueued).To(BeTrue())
p++
// dequeue the ACK frame
Expect(tracker.GetAckFrame(true)).ToNot(BeNil())
}
})
It("resets the counter when a non-queued ACK frame is generated", func() {
receiveAndAck10Packets()
rcvTime := time.Now()
tracker.ReceivedPacket(11, rcvTime, true)
Expect(tracker.GetAckFrame(false)).ToNot(BeNil())
tracker.ReceivedPacket(12, rcvTime, true)
Expect(tracker.GetAckFrame(true)).To(BeNil())
tracker.ReceivedPacket(13, rcvTime, true)
Expect(tracker.GetAckFrame(false)).ToNot(BeNil())
})
It("only sets the timer when receiving a ack-eliciting packets", func() {
receiveAndAck10Packets()
tracker.ReceivedPacket(11, time.Now(), false)
Expect(tracker.ackQueued).To(BeFalse())
Expect(tracker.GetAlarmTimeout()).To(BeZero())
rcvTime := time.Now().Add(10 * time.Millisecond)
tracker.ReceivedPacket(12, rcvTime, true)
Expect(tracker.ackQueued).To(BeFalse())
Expect(tracker.GetAlarmTimeout()).To(Equal(rcvTime.Add(protocol.MaxAckDelay)))
})
It("queues an ACK if it was reported missing before", func() {
receiveAndAck10Packets()
tracker.ReceivedPacket(11, time.Now(), true)
tracker.ReceivedPacket(13, time.Now(), true)
ack := tracker.GetAckFrame(true) // ACK: 1-11 and 13, missing: 12
Expect(ack).ToNot(BeNil())
Expect(ack.HasMissingRanges()).To(BeTrue())
Expect(tracker.ackQueued).To(BeFalse())
tracker.ReceivedPacket(12, time.Now(), true)
Expect(tracker.ackQueued).To(BeTrue())
})
It("doesn't queue an ACK if it was reported missing before, but is below the threshold", func() {
receiveAndAck10Packets()
// 11 is missing
tracker.ReceivedPacket(12, time.Now(), true)
tracker.ReceivedPacket(13, time.Now(), true)
ack := tracker.GetAckFrame(true) // ACK: 1-10, 12-13
Expect(ack).ToNot(BeNil())
// now receive 11
tracker.IgnoreBelow(12)
tracker.ReceivedPacket(11, time.Now(), false)
ack = tracker.GetAckFrame(true)
Expect(ack).To(BeNil())
})
It("doesn't queue an ACK if for non-ack-eliciting packets arriving out-of-order", func() {
receiveAndAck10Packets()
tracker.ReceivedPacket(11, time.Now(), true)
Expect(tracker.GetAckFrame(true)).To(BeNil())
tracker.ReceivedPacket(13, time.Now(), false) // receive a non-ack-eliciting packet out-of-order
Expect(tracker.GetAckFrame(true)).To(BeNil())
})
It("doesn't queue an ACK if packets arrive out-of-order, but haven't been acknowledged yet", func() {
receiveAndAck10Packets()
Expect(tracker.lastAck).ToNot(BeNil())
tracker.ReceivedPacket(12, time.Now(), false)
Expect(tracker.GetAckFrame(true)).To(BeNil())
// 11 is received out-of-order, but this hasn't been reported in an ACK frame yet
tracker.ReceivedPacket(11, time.Now(), true)
Expect(tracker.GetAckFrame(true)).To(BeNil())
})
})
Context("ACK generation", func() {
It("generates an ACK for an ack-eliciting packet, if no ACK is queued yet", func() {
tracker.ReceivedPacket(1, time.Now(), true)
// The first packet is always acknowledged.
Expect(tracker.GetAckFrame(true)).ToNot(BeNil())
})
It("doesn't generate ACK for a non-ack-eliciting packet, if no ACK is queued yet", func() {
tracker.ReceivedPacket(1, time.Now(), true)
// The first packet is always acknowledged.
Expect(tracker.GetAckFrame(true)).ToNot(BeNil())
tracker.ReceivedPacket(2, time.Now(), false)
Expect(tracker.GetAckFrame(false)).To(BeNil())
tracker.ReceivedPacket(3, time.Now(), true)
ack := tracker.GetAckFrame(false)
Expect(ack).ToNot(BeNil())
Expect(ack.LowestAcked()).To(Equal(protocol.PacketNumber(1)))
Expect(ack.LargestAcked()).To(Equal(protocol.PacketNumber(3)))
})
Context("for queued ACKs", func() {
BeforeEach(func() {
tracker.ackQueued = true
})
It("generates a simple ACK frame", func() {
tracker.ReceivedPacket(1, time.Now(), true)
tracker.ReceivedPacket(2, time.Now(), true)
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(ack.LargestAcked()).To(Equal(protocol.PacketNumber(2)))
Expect(ack.LowestAcked()).To(Equal(protocol.PacketNumber(1)))
Expect(ack.HasMissingRanges()).To(BeFalse())
})
It("generates an ACK for packet number 0", func() {
tracker.ReceivedPacket(0, time.Now(), true)
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(ack.LargestAcked()).To(Equal(protocol.PacketNumber(0)))
Expect(ack.LowestAcked()).To(Equal(protocol.PacketNumber(0)))
Expect(ack.HasMissingRanges()).To(BeFalse())
})
It("sets the delay time", func() {
tracker.ReceivedPacket(1, time.Now(), true)
tracker.ReceivedPacket(2, time.Now().Add(-1337*time.Millisecond), true)
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(ack.DelayTime).To(BeNumerically("~", 1337*time.Millisecond, 50*time.Millisecond))
})
It("uses a 0 delay time if the delay would be negative", func() {
tracker.ReceivedPacket(0, time.Now().Add(time.Hour), true)
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(ack.DelayTime).To(BeZero())
})
It("saves the last sent ACK", func() {
tracker.ReceivedPacket(1, time.Now(), true)
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(tracker.lastAck).To(Equal(ack))
tracker.ReceivedPacket(2, time.Now(), true)
tracker.ackQueued = true
ack = tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(tracker.lastAck).To(Equal(ack))
})
It("generates an ACK frame with missing packets", func() {
tracker.ReceivedPacket(1, time.Now(), true)
tracker.ReceivedPacket(4, time.Now(), true)
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(ack.LargestAcked()).To(Equal(protocol.PacketNumber(4)))
Expect(ack.LowestAcked()).To(Equal(protocol.PacketNumber(1)))
Expect(ack.AckRanges).To(Equal([]wire.AckRange{
{Smallest: 4, Largest: 4},
{Smallest: 1, Largest: 1},
}))
})
It("generates an ACK for packet number 0 and other packets", func() {
tracker.ReceivedPacket(0, time.Now(), true)
tracker.ReceivedPacket(1, time.Now(), true)
tracker.ReceivedPacket(3, time.Now(), true)
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(ack.LargestAcked()).To(Equal(protocol.PacketNumber(3)))
Expect(ack.LowestAcked()).To(Equal(protocol.PacketNumber(0)))
Expect(ack.AckRanges).To(Equal([]wire.AckRange{
{Smallest: 3, Largest: 3},
{Smallest: 0, Largest: 1},
}))
})
It("doesn't add delayed packets to the packetHistory", func() {
tracker.IgnoreBelow(7)
tracker.ReceivedPacket(4, time.Now(), true)
tracker.ReceivedPacket(10, time.Now(), true)
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(ack.LargestAcked()).To(Equal(protocol.PacketNumber(10)))
Expect(ack.LowestAcked()).To(Equal(protocol.PacketNumber(10)))
})
It("deletes packets from the packetHistory when a lower limit is set", func() {
for i := 1; i <= 12; i++ {
tracker.ReceivedPacket(protocol.PacketNumber(i), time.Now(), true)
}
tracker.IgnoreBelow(7)
// check that the packets were deleted from the receivedPacketHistory by checking the values in an ACK frame
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(ack.LargestAcked()).To(Equal(protocol.PacketNumber(12)))
Expect(ack.LowestAcked()).To(Equal(protocol.PacketNumber(7)))
Expect(ack.HasMissingRanges()).To(BeFalse())
})
// TODO: remove this test when dropping support for STOP_WAITINGs
It("handles a lower limit of 0", func() {
tracker.IgnoreBelow(0)
tracker.ReceivedPacket(1337, time.Now(), true)
ack := tracker.GetAckFrame(true)
Expect(ack).ToNot(BeNil())
Expect(ack.LargestAcked()).To(Equal(protocol.PacketNumber(1337)))
})
It("resets all counters needed for the ACK queueing decision when sending an ACK", func() {
tracker.ReceivedPacket(1, time.Now(), true)
tracker.ackAlarm = time.Now().Add(-time.Minute)
Expect(tracker.GetAckFrame(true)).ToNot(BeNil())
Expect(tracker.GetAlarmTimeout()).To(BeZero())
Expect(tracker.ackElicitingPacketsReceivedSinceLastAck).To(BeZero())
Expect(tracker.ackQueued).To(BeFalse())
})
It("doesn't generate an ACK when none is queued and the timer is not set", func() {
tracker.ReceivedPacket(1, time.Now(), true)
tracker.ackQueued = false
tracker.ackAlarm = time.Time{}
Expect(tracker.GetAckFrame(true)).To(BeNil())
})
It("doesn't generate an ACK when none is queued and the timer has not yet expired", func() {
tracker.ReceivedPacket(1, time.Now(), true)
tracker.ackQueued = false
tracker.ackAlarm = time.Now().Add(time.Minute)
Expect(tracker.GetAckFrame(true)).To(BeNil())
})
It("generates an ACK when the timer has expired", func() {
tracker.ReceivedPacket(1, time.Now(), true)
tracker.ackQueued = false
tracker.ackAlarm = time.Now().Add(-time.Minute)
Expect(tracker.GetAckFrame(true)).ToNot(BeNil())
})
})
})
})
})