From 63921b6dcb2ab5600caf1730e962c991596bb477 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Fri, 13 Mar 2020 17:17:28 +0700
Subject: [PATCH] qlog dropped encryption levels

---
 qlog/event.go     | 14 ++++++++++++++
 qlog/qlog.go      | 16 ++++++++++++++++
 qlog/qlog_test.go | 21 ++++++++++++++++++++-
 session.go        |  3 +++
 4 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/qlog/event.go b/qlog/event.go
index e4086a479..261c3ad0b 100644
--- a/qlog/event.go
+++ b/qlog/event.go
@@ -238,3 +238,17 @@ func (e eventKeyUpdated) MarshalJSONObject(enc *gojay.Encoder) {
 	enc.StringKey("key_type", e.KeyType.String())
 	enc.Uint64KeyOmitEmpty("generation", uint64(e.Generation))
 }
+
+type eventKeyRetired struct {
+	KeyType    keyType
+	Generation protocol.KeyPhase
+}
+
+func (e eventKeyRetired) Category() category { return categorySecurity }
+func (e eventKeyRetired) Name() string       { return "key_retired" }
+func (e eventKeyRetired) IsNil() bool        { return false }
+
+func (e eventKeyRetired) MarshalJSONObject(enc *gojay.Encoder) {
+	enc.StringKey("trigger", "tls")
+	enc.StringKey("key_type", e.KeyType.String())
+}
diff --git a/qlog/qlog.go b/qlog/qlog.go
index 47f33cde7..1b88b91f4 100644
--- a/qlog/qlog.go
+++ b/qlog/qlog.go
@@ -25,6 +25,7 @@ type Tracer interface {
 	UpdatedPTOCount(time.Time, uint32)
 	UpdatedKeyFromTLS(time.Time, protocol.EncryptionLevel, protocol.Perspective)
 	UpdatedKey(t time.Time, generation protocol.KeyPhase, remote bool)
+	DroppedEncryptionLevel(time.Time, protocol.EncryptionLevel)
 }
 
 type tracer struct {
@@ -210,3 +211,18 @@ func (t *tracer) UpdatedKey(time time.Time, generation protocol.KeyPhase, remote
 		},
 	})
 }
+
+func (t *tracer) DroppedEncryptionLevel(time time.Time, encLevel protocol.EncryptionLevel) {
+	t.events = append(t.events, event{
+		Time: time,
+		eventDetails: eventKeyRetired{
+			KeyType: encLevelToKeyType(encLevel, protocol.PerspectiveServer),
+		},
+	})
+	t.events = append(t.events, event{
+		Time: time,
+		eventDetails: eventKeyRetired{
+			KeyType: encLevelToKeyType(encLevel, protocol.PerspectiveClient),
+		},
+	})
+}
diff --git a/qlog/qlog_test.go b/qlog/qlog_test.go
index 364171134..19941e006 100644
--- a/qlog/qlog_test.go
+++ b/qlog/qlog_test.go
@@ -328,7 +328,7 @@ var _ = Describe("Tracer", func() {
 			Expect(ev).ToNot(HaveKey("new"))
 		})
 
-		It("records QUIC key udpates", func() {
+		It("records QUIC key updates", func() {
 			now := time.Now()
 			tracer.UpdatedKey(now, 1337, true)
 			entries := exportAndParse()
@@ -347,5 +347,24 @@ var _ = Describe("Tracer", func() {
 			Expect(keyTypes).To(ContainElement("server_1rtt_secret"))
 			Expect(keyTypes).To(ContainElement("client_1rtt_secret"))
 		})
+
+		It("records dropped encryption levels", func() {
+			now := time.Now()
+			tracer.DroppedEncryptionLevel(now, protocol.EncryptionInitial)
+			entries := exportAndParse()
+			Expect(entries).To(HaveLen(2))
+			var keyTypes []string
+			for _, entry := range entries {
+				Expect(entry.Time).To(BeTemporally("~", now, time.Millisecond))
+				Expect(entry.Category).To(Equal("security"))
+				Expect(entry.Name).To(Equal("key_retired"))
+				ev := entry.Event
+				Expect(ev).To(HaveKeyWithValue("trigger", "tls"))
+				Expect(ev).To(HaveKey("key_type"))
+				keyTypes = append(keyTypes, ev["key_type"].(string))
+			}
+			Expect(keyTypes).To(ContainElement("server_initial_secret"))
+			Expect(keyTypes).To(ContainElement("client_initial_secret"))
+		})
 	})
 })
diff --git a/session.go b/session.go
index 676fad353..41232920a 100644
--- a/session.go
+++ b/session.go
@@ -1167,6 +1167,9 @@ func (s *session) dropEncryptionLevel(encLevel protocol.EncryptionLevel) {
 	}
 	s.sentPacketHandler.DropPackets(encLevel)
 	s.receivedPacketHandler.DropPackets(encLevel)
+	if s.qlogger != nil {
+		s.qlogger.DroppedEncryptionLevel(time.Now(), encLevel)
+	}
 }
 
 func (s *session) processTransportParameters(params *handshake.TransportParameters) {