fix logging of dropped 0-RTT keys

Client and server only possess write or read 0-RTT keys, respectively.
We should therefore only emit a single event when those are dropped.

qlog/qlog.go

@@ -402,8 +402,12 @@ func (t *connectionTracer) UpdatedKey(generation protocol.KeyPhase, remote bool)
 func (t *connectionTracer) DroppedEncryptionLevel(encLevel protocol.EncryptionLevel) {
 	t.mutex.Lock()
 	now := time.Now()
+	if encLevel == protocol.Encryption0RTT {
+		t.recordEvent(now, &eventKeyRetired{KeyType: encLevelToKeyType(encLevel, t.perspective)})
+	} else {
 		t.recordEvent(now, &eventKeyRetired{KeyType: encLevelToKeyType(encLevel, protocol.PerspectiveServer)})
 		t.recordEvent(now, &eventKeyRetired{KeyType: encLevelToKeyType(encLevel, protocol.PerspectiveClient)})
+	}
 	t.mutex.Unlock()
 }
 

qlog/qlog_test.go

@@ -721,6 +721,18 @@ var _ = Describe("Tracing", func() {
 				Expect(keyTypes).To(ContainElement("client_initial_secret"))
 			})
 
+			It("records dropped 0-RTT keys", func() {
+				tracer.DroppedEncryptionLevel(protocol.Encryption0RTT)
+				entries := exportAndParse()
+				Expect(entries).To(HaveLen(1))
+				entry := entries[0]
+				Expect(entry.Time).To(BeTemporally("~", time.Now(), scaleDuration(10*time.Millisecond)))
+				Expect(entry.Name).To(Equal("security:key_retired"))
+				ev := entry.Event
+				Expect(ev).To(HaveKeyWithValue("trigger", "tls"))
+				Expect(ev).To(HaveKeyWithValue("key_type", "server_0rtt_secret"))
+			})
+
 			It("records dropped keys", func() {
 				tracer.DroppedKey(42)
 				entries := exportAndParse()