From 4eb088caa6869eaec97f907a2c2e9b5bb075c820 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Fri, 22 Apr 2016 13:15:55 +0700
Subject: [PATCH] increase missingReports counter for NACKed packets

---
 ackhandler/outgoing_packet_ack_handler.go     | 13 ++++--
 .../outgoing_packet_ack_handler_test.go       | 40 +++++++++++++++++--
 2 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/ackhandler/outgoing_packet_ack_handler.go b/ackhandler/outgoing_packet_ack_handler.go
index 89b15ca5..71662fbc 100644
--- a/ackhandler/outgoing_packet_ack_handler.go
+++ b/ackhandler/outgoing_packet_ack_handler.go
@@ -150,7 +150,7 @@ func (h *outgoingPacketAckHandler) ReceivedAck(ackFrame *frames.AckFrame) error
 		delete(h.packetHistory, i)
 	}
 
-	// delete packets with a packet number higher than highestInOrderAckedPacketNumber that have already been ACKed
+	// increase MissingReports counter of NACKed packets
 	// this is the case if the PacketNumber is *not* contained in any of the NACK ranges
 	if ackFrame.HasNACK() {
 		nackRangeIndex := len(ackFrame.NackRanges) - 1
@@ -163,11 +163,16 @@ func (h *outgoingPacketAckHandler) ReceivedAck(ackFrame *frames.AckFrame) error
 					nackRange = ackFrame.NackRanges[nackRangeIndex]
 				}
 			}
-			// PacketNumber i is not contained in a NACK range
+			// PacketNumber i is not contained in a NACK range, increase it's missingReports counter
 			if i >= nackRange.FirstPacketNumber && i <= nackRange.LastPacketNumber {
-				continue
+				packet, ok := h.packetHistory[i]
+				if !ok {
+					return errMapAccess
+				}
+				packet.MissingReports++
+				// ToDo: do something as when packet.MissionReports > threshold
 			}
-			delete(h.packetHistory, i)
+			// ToDo: delete packet from history, since it already has been ACKed
 		}
 	}
 
diff --git a/ackhandler/outgoing_packet_ack_handler_test.go b/ackhandler/outgoing_packet_ack_handler_test.go
index 10f3ad07..5a60ddc1 100644
--- a/ackhandler/outgoing_packet_ack_handler_test.go
+++ b/ackhandler/outgoing_packet_ack_handler_test.go
@@ -177,7 +177,8 @@ var _ = Describe("AckHandler", func() {
 				Expect(err).ToNot(HaveOccurred())
 				Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(1)))
 				Expect(handler.packetHistory).To(HaveKey(protocol.PacketNumber(2)))
-				Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(3)))
+				Expect(handler.packetHistory[2].MissingReports).To(Equal(uint8(1)))
+				// Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(3)))
 				Expect(handler.packetHistory).To(HaveKey(protocol.PacketNumber(4)))
 			})
 
@@ -196,7 +197,9 @@ var _ = Describe("AckHandler", func() {
 				Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(1)))
 				Expect(handler.packetHistory).To(HaveKey(protocol.PacketNumber(2)))
 				Expect(handler.packetHistory).To(HaveKey(protocol.PacketNumber(3)))
-				Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(4)))
+				Expect(handler.packetHistory[2].MissingReports).To(Equal(uint8(1)))
+				Expect(handler.packetHistory[3].MissingReports).To(Equal(uint8(1)))
+				// Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(4)))
 			})
 
 			It("handles an ACK with multiple NACK ranges", func() {
@@ -217,9 +220,11 @@ var _ = Describe("AckHandler", func() {
 				Expect(err).ToNot(HaveOccurred())
 				Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(1)))
 				Expect(handler.packetHistory).To(HaveKey(protocol.PacketNumber(2)))
-				Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(3)))
+				Expect(handler.packetHistory[2].MissingReports).To(Equal(uint8(1)))
+				// Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(3)))
 				Expect(handler.packetHistory).To(HaveKey(protocol.PacketNumber(4)))
-				Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(5)))
+				Expect(handler.packetHistory[4].MissingReports).To(Equal(uint8(1)))
+				// Expect(handler.packetHistory).ToNot(HaveKey(protocol.PacketNumber(5)))
 			})
 
 			It("rejects an ACK with a NACK that has incorrect entropy", func() {
@@ -258,6 +263,33 @@ var _ = Describe("AckHandler", func() {
 				err = handler.ReceivedAck(&ack)
 				Expect(err).ToNot(HaveOccurred())
 			})
+
+			It("increments the missingReports counter every time a NACK for a packet is received", func() {
+				nackRange1 := frames.NackRange{FirstPacketNumber: 4, LastPacketNumber: 4}
+				nackRange2 := frames.NackRange{FirstPacketNumber: 2, LastPacketNumber: 2}
+				entropy := EntropyAccumulator(0)
+				entropy.Add(1, packets[0].EntropyBit)
+				entropy.Add(3, packets[2].EntropyBit)
+				ack1 := frames.AckFrame{
+					LargestObserved: 3,
+					Entropy:         byte(entropy),
+					NackRanges:      []frames.NackRange{nackRange2},
+				}
+				err := handler.ReceivedAck(&ack1)
+				Expect(err).ToNot(HaveOccurred())
+				entropy.Add(5, packets[4].EntropyBit)
+				ack2 := frames.AckFrame{
+					LargestObserved: 5,
+					Entropy:         byte(entropy),
+					NackRanges:      []frames.NackRange{nackRange1, nackRange2},
+				}
+				err = handler.ReceivedAck(&ack2)
+				Expect(err).ToNot(HaveOccurred())
+				Expect(handler.packetHistory).To(HaveKey(protocol.PacketNumber(2)))
+				Expect(handler.packetHistory).To(HaveKey(protocol.PacketNumber(4)))
+				Expect(handler.packetHistory[2].MissingReports).To(Equal(uint8(2)))
+				Expect(handler.packetHistory[4].MissingReports).To(Equal(uint8(1)))
+			})
 		})
 	})
 })