make it possible to call ConnectionState during the handshake

conn.go

@@ -126,6 +126,9 @@ type Conn struct {
 	used0RTT bool
 
 	tmp [16]byte
+
+	connStateMutex sync.Mutex
+	connState      ConnectionStateWith0RTT
 }
 
 // Access to net.Conn methods.
@@ -1566,19 +1569,16 @@ func (c *Conn) handshakeContext(ctx context.Context) (ret error) {
 
 // ConnectionState returns basic TLS details about the connection.
 func (c *Conn) ConnectionState() ConnectionState {
-	c.handshakeMutex.Lock()
-	defer c.handshakeMutex.Unlock()
-	return c.connectionStateLocked()
+	c.connStateMutex.Lock()
+	defer c.connStateMutex.Unlock()
+	return c.connState.ConnectionState
 }
 
 // ConnectionStateWith0RTT returns basic TLS details (incl. 0-RTT status) about the connection.
 func (c *Conn) ConnectionStateWith0RTT() ConnectionStateWith0RTT {
-	c.handshakeMutex.Lock()
-	defer c.handshakeMutex.Unlock()
-	return ConnectionStateWith0RTT{
-		ConnectionState: c.connectionStateLocked(),
-		Used0RTT:        c.used0RTT,
-	}
+	c.connStateMutex.Lock()
+	defer c.connStateMutex.Unlock()
+	return c.connState
 }
 
 func (c *Conn) connectionStateLocked() ConnectionState {
@@ -1609,6 +1609,15 @@ func (c *Conn) connectionStateLocked() ConnectionState {
 	return toConnectionState(state)
 }
 
+func (c *Conn) updateConnectionState() {
+	c.connStateMutex.Lock()
+	defer c.connStateMutex.Unlock()
+	c.connState = ConnectionStateWith0RTT{
+		Used0RTT:        c.used0RTT,
+		ConnectionState: c.connectionStateLocked(),
+	}
+}
+
 // OCSPResponse returns the stapled OCSP response from the TLS server, if
 // any. (Only valid for client connections.)
 func (c *Conn) OCSPResponse() []byte {

handshake_client.go

@@ -290,6 +290,7 @@ func (c *Conn) clientHandshake(ctx context.Context) (err error) {
 		c.config.ClientSessionCache.Put(cacheKey, toClientSessionState(hs.session))
 	}
 
+	c.updateConnectionState()
 	return nil
 }
 

handshake_client_tls13.go

@@ -87,6 +87,7 @@ func (hs *clientHandshakeStateTLS13) handshake() error {
 	if err := hs.processServerHello(); err != nil {
 		return err
 	}
+	c.updateConnectionState()
 	if err := hs.sendDummyChangeCipherSpec(); err != nil {
 		return err
 	}
@@ -99,6 +100,7 @@ func (hs *clientHandshakeStateTLS13) handshake() error {
 	if err := hs.readServerCertificate(); err != nil {
 		return err
 	}
+	c.updateConnectionState()
 	if err := hs.readServerFinished(); err != nil {
 		return err
 	}
@@ -113,7 +115,7 @@ func (hs *clientHandshakeStateTLS13) handshake() error {
 	}
 
 	c.isHandshakeComplete.Store(true)
-
+	c.updateConnectionState()
 	return nil
 }
 

handshake_server.go

@@ -131,6 +131,7 @@ func (hs *serverHandshakeState) handshake() error {
 	c.ekm = ekmFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.clientHello.random, hs.hello.random)
 	c.isHandshakeComplete.Store(true)
 
+	c.updateConnectionState()
 	return nil
 }
 

handshake_server_test.go

@@ -1507,6 +1507,7 @@ func TestSNIGivenOnFailure(t *testing.T) {
 		t.Error("No error reported from server")
 	}
 
+	hs.c.updateConnectionState()
 	cs := hs.c.ConnectionState()
 	if cs.HandshakeComplete {
 		t.Error("Handshake registered as complete")

handshake_server_tls13.go

@@ -56,6 +56,7 @@ func (hs *serverHandshakeStateTLS13) handshake() error {
 	if err := hs.checkForResumption(); err != nil {
 		return err
 	}
+	c.updateConnectionState()
 	if err := hs.pickCertificate(); err != nil {
 		return err
 	}
@@ -78,12 +79,13 @@ func (hs *serverHandshakeStateTLS13) handshake() error {
 	if err := hs.readClientCertificate(); err != nil {
 		return err
 	}
+	c.updateConnectionState()
 	if err := hs.readClientFinished(); err != nil {
 		return err
 	}
 
 	c.isHandshakeComplete.Store(true)
-
+	c.updateConnectionState()
 	return nil
 }
 

record_layer_test.go

@@ -74,8 +74,26 @@ func TestAlternativeRecordLayer(t *testing.T) {
 	cOut := make(chan interface{}, 10)
 	defer close(cOut)
 
-	serverKeyChan := make(chan *exportedKey, 4) // see server loop for the order in which keys are provided
+	testConfig := testConfig.Clone()
+	testConfig.NextProtos = []string{"alpn"}
+
 	// server side
+	errChan := make(chan error)
+	serverConn := Server(
+		&unusedConn{},
+		testConfig,
+		&ExtraConfig{AlternativeRecordLayer: &recordLayerWithKeys{in: sIn, out: sOut}},
+	)
+	go func() {
+		defer serverConn.Close()
+		err := serverConn.Handshake()
+		connState := serverConn.ConnectionState()
+		if !connState.HandshakeComplete {
+			t.Fatal("expected the handshake to have completed")
+		}
+		errChan <- err
+	}()
+	serverKeyChan := make(chan *exportedKey, 4) // see server loop for the order in which keys are provided
 	go func() {
 		var counter int
 		for {
@@ -88,6 +106,16 @@ func TestAlternativeRecordLayer(t *testing.T) {
 				if c.([]byte)[0] != typeServerHello {
 					t.Errorf("expected ServerHello")
 				}
+				connState := serverConn.ConnectionState()
+				if connState.HandshakeComplete {
+					t.Error("didn't expect the handshake to be complete yet")
+				}
+				if connState.Version != VersionTLS13 {
+					t.Errorf("expected TLS 1.3, got %x", connState.Version)
+				}
+				if connState.NegotiatedProtocol == "" {
+					t.Error("expected ALPN to be negotiated")
+				}
 			case 1:
 				keyEv := c.(*exportedKey)
 				if keyEv.typ != "read" || keyEv.encLevel != EncryptionHandshake {
@@ -139,6 +167,12 @@ func TestAlternativeRecordLayer(t *testing.T) {
 	}()
 
 	// client side
+	clientConn := Client(
+		&unusedConn{},
+		testConfig,
+		&ExtraConfig{AlternativeRecordLayer: &recordLayerWithKeys{in: cIn, out: cOut}},
+	)
+	defer clientConn.Close()
 	go func() {
 		var counter int
 		for {
@@ -151,6 +185,13 @@ func TestAlternativeRecordLayer(t *testing.T) {
 				if c.([]byte)[0] != typeClientHello {
 					t.Errorf("expected ClientHello")
 				}
+				connState := clientConn.ConnectionState()
+				if connState.HandshakeComplete {
+					t.Error("didn't expect the handshake to be complete yet")
+				}
+				if len(connState.PeerCertificates) != 0 {
+					t.Error("didn't expect a certificate yet")
+				}
 			case 1:
 				keyEv := c.(*exportedKey)
 				if keyEv.typ != "write" || keyEv.encLevel != EncryptionHandshake {
@@ -189,24 +230,19 @@ func TestAlternativeRecordLayer(t *testing.T) {
 		}
 	}()
 
-	errChan := make(chan error)
-	go func() {
-		extraConf := &ExtraConfig{
-			AlternativeRecordLayer: &recordLayerWithKeys{in: sIn, out: sOut},
-		}
-		tlsConn := Server(&unusedConn{}, testConfig, extraConf)
-		defer tlsConn.Close()
-		errChan <- tlsConn.Handshake()
-	}()
-
-	extraConf := &ExtraConfig{
-		AlternativeRecordLayer: &recordLayerWithKeys{in: cIn, out: cOut},
-	}
-	tlsConn := Client(&unusedConn{}, testConfig, extraConf)
-	defer tlsConn.Close()
-	if err := tlsConn.Handshake(); err != nil {
+	if err := clientConn.Handshake(); err != nil {
 		t.Fatalf("Handshake failed: %s", err)
 	}
+	connState := clientConn.ConnectionState()
+	if !connState.HandshakeComplete {
+		t.Fatal("expected the handshake to have completed")
+	}
+	if connState.Version != VersionTLS13 {
+		t.Errorf("expected TLS 1.3, got %x", connState.Version)
+	}
+	if len(connState.PeerCertificates) == 0 {
+		t.Fatal("expected the certificate to be set")
+	}
 
 	select {
 	case <-time.After(500 * time.Millisecond):