use a directed aeadChanged chan in the session

session.go

@@ -78,7 +78,7 @@ type session struct {
 
 	// this channel is passed to the CryptoSetup and receives the current encryption level
 	// it is closed as soon as the handshake is complete
-	aeadChanged       chan protocol.EncryptionLevel
+	aeadChanged       <-chan protocol.EncryptionLevel
 	handshakeComplete bool
 
 	nextAckScheduledTime time.Time
@@ -121,8 +121,10 @@ func newSession(conn connection, v protocol.VersionNumber, connectionID protocol
 	} else {
 		sourceAddr = []byte(conn.RemoteAddr().String())
 	}
+	aeadChanged := make(chan protocol.EncryptionLevel, 2)
+	s.aeadChanged = aeadChanged
 	var err error
-	s.cryptoSetup, err = handshake.NewCryptoSetup(connectionID, sourceAddr, v, sCfg, cryptoStream, s.connectionParameters, supportedVersions, s.aeadChanged)
+	s.cryptoSetup, err = handshake.NewCryptoSetup(connectionID, sourceAddr, v, sCfg, cryptoStream, s.connectionParameters, supportedVersions, aeadChanged)
 	if err != nil {
 		return nil, err
 	}
@@ -147,9 +149,11 @@ func newClientSession(conn connection, hostname string, v protocol.VersionNumber
 	s.receivedPacketHandler = ackhandler.NewReceivedPacketHandler(s.ackAlarmChanged)
 	s.setup()
 
+	aeadChanged := make(chan protocol.EncryptionLevel, 2)
+	s.aeadChanged = aeadChanged
 	cryptoStream, _ := s.OpenStream()
 	var err error
-	s.cryptoSetup, err = handshake.NewCryptoSetupClient(hostname, connectionID, v, cryptoStream, tlsConfig, s.connectionParameters, s.aeadChanged, negotiatedVersions)
+	s.cryptoSetup, err = handshake.NewCryptoSetupClient(hostname, connectionID, v, cryptoStream, tlsConfig, s.connectionParameters, aeadChanged, negotiatedVersions)
 	if err != nil {
 		return nil, err
 	}

session_test.go

@@ -125,11 +125,12 @@ func areSessionsRunning() bool {
 
 var _ = Describe("Session", func() {
 	var (
-		sess       *session
-		clientSess *session
-		scfg       *handshake.ServerConfig
-		mconn      *mockConnection
-		cpm        *mockConnectionParametersManager
+		sess        *session
+		clientSess  *session
+		scfg        *handshake.ServerConfig
+		mconn       *mockConnection
+		cpm         *mockConnectionParametersManager
+		aeadChanged chan<- protocol.EncryptionLevel
 	)
 
 	BeforeEach(func() {
@@ -154,6 +155,9 @@ var _ = Describe("Session", func() {
 		Expect(err).NotTo(HaveOccurred())
 		sess = pSess.(*session)
 		Expect(sess.streamsMap.openStreams).To(HaveLen(1)) // Crypto stream
+		// we need an aeadChanged chan that we can write to
+		// since type assertions on chans are not possible, we have to extract it from the CryptoSetup
+		aeadChanged = *(*chan<- protocol.EncryptionLevel)(unsafe.Pointer(reflect.ValueOf(sess.cryptoSetup).Elem().FieldByName("aeadChanged").UnsafeAddr()))
 
 		cpm = &mockConnectionParametersManager{idleTime: 60 * time.Second}
 		sess.connectionParameters = cpm
@@ -1166,9 +1170,9 @@ var _ = Describe("Session", func() {
 	It("tells the packetPacker when forward-secure encryption is used", func() {
 		go sess.run()
 		defer sess.Close(nil)
-		sess.aeadChanged <- protocol.EncryptionSecure
+		aeadChanged <- protocol.EncryptionSecure
 		Consistently(func() bool { return sess.packer.isForwardSecure }).Should(BeFalse())
-		sess.aeadChanged <- protocol.EncryptionForwardSecure
+		aeadChanged <- protocol.EncryptionForwardSecure
 		Eventually(func() bool { return sess.packer.isForwardSecure }).Should(BeTrue())
 	})
 
@@ -1251,7 +1255,7 @@ var _ = Describe("Session", func() {
 		})
 
 		It("ignores undecryptable packets after the handshake is complete", func() {
-			close(sess.aeadChanged)
+			close(aeadChanged)
 			go sess.run()
 			sendUndecryptablePackets()
 			Consistently(sess.undecryptablePackets).Should(BeEmpty())
@@ -1280,7 +1284,7 @@ var _ = Describe("Session", func() {
 			callbackSession = s
 		}
 		sess.cryptoChangeCallback = cb
-		sess.aeadChanged <- protocol.EncryptionSecure
+		aeadChanged <- protocol.EncryptionSecure
 		go sess.run()
 		defer sess.Close(nil)
 		Eventually(func() bool { return callbackCalled }).Should(BeTrue())
@@ -1297,8 +1301,8 @@ var _ = Describe("Session", func() {
 			callbackCalledWith = p
 		}
 		sess.cryptoChangeCallback = cb
-		sess.aeadChanged <- protocol.EncryptionForwardSecure
-		close(sess.aeadChanged)
+		aeadChanged <- protocol.EncryptionForwardSecure
+		close(aeadChanged)
 		go sess.run()
 		defer sess.Close(nil)
 		Eventually(func() bool { return callbackCalledWith }).Should(BeTrue())
@@ -1334,7 +1338,7 @@ var _ = Describe("Session", func() {
 		})
 
 		It("uses ICSL after handshake", func(done Done) {
-			close(sess.aeadChanged)
+			close(aeadChanged)
 			cpm.idleTime = 0 * time.Millisecond
 			sess.packer.connectionParameters = sess.connectionParameters
 			sess.run() // Would normally not return