use separate constructors for client and server for the TLS crypto setup

internal/handshake/crypto_setup_tls.go

@@ -35,36 +35,52 @@ var newMintController = func(conn *mint.Conn) crypto.MintController {
 	return &mintController{conn}
 }
 
-// NewCryptoSetupTLS creates a new CryptoSetup instance for a server
-func NewCryptoSetupTLS(
-	hostname string, // only needed for the client
-	perspective protocol.Perspective,
-	version protocol.VersionNumber,
+// NewCryptoSetupTLSServer creates a new TLS CryptoSetup instance for a server
+func NewCryptoSetupTLSServer(
 	tlsConfig *tls.Config,
 	transportParams *TransportParameters,
 	aeadChanged chan<- protocol.EncryptionLevel,
+	version protocol.VersionNumber,
 ) (CryptoSetup, ParamsNegotiator, error) {
-	mintConf, err := tlsToMintConfig(tlsConfig, perspective)
+	mintConf, err := tlsToMintConfig(tlsConfig, protocol.PerspectiveServer)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	params := newParamsNegotiator(protocol.PerspectiveServer, version, transportParams)
+	return &cryptoSetupTLS{
+		perspective:      protocol.PerspectiveServer,
+		mintConf:         mintConf,
+		nullAEAD:         crypto.NewNullAEAD(protocol.PerspectiveServer, version),
+		keyDerivation:    crypto.DeriveAESKeys,
+		aeadChanged:      aeadChanged,
+		extensionHandler: newExtensionHandlerServer(params),
+	}, params, nil
+}
+
+// NewCryptoSetupTLSClient creates a new TLS CryptoSetup instance for a client
+func NewCryptoSetupTLSClient(
+	hostname string, // only needed for the client
+	tlsConfig *tls.Config,
+	transportParams *TransportParameters,
+	aeadChanged chan<- protocol.EncryptionLevel,
+	version protocol.VersionNumber,
+) (CryptoSetup, ParamsNegotiator, error) {
+	mintConf, err := tlsToMintConfig(tlsConfig, protocol.PerspectiveClient)
 	if err != nil {
 		return nil, nil, err
 	}
 	mintConf.ServerName = hostname
 
-	params := newParamsNegotiator(perspective, version, transportParams)
-	cs := &cryptoSetupTLS{
-		perspective:   perspective,
-		mintConf:      mintConf,
-		nullAEAD:      crypto.NewNullAEAD(perspective, version),
-		keyDerivation: crypto.DeriveAESKeys,
-		aeadChanged:   aeadChanged,
-	}
-	if perspective == protocol.PerspectiveClient {
-		cs.extensionHandler = newExtensionHandlerClient(params)
-	} else {
-		cs.extensionHandler = newExtensionHandlerServer(params)
-	}
-
-	return cs, params, nil
+	params := newParamsNegotiator(protocol.PerspectiveClient, version, transportParams)
+	return &cryptoSetupTLS{
+		perspective:      protocol.PerspectiveClient,
+		mintConf:         mintConf,
+		nullAEAD:         crypto.NewNullAEAD(protocol.PerspectiveClient, version),
+		keyDerivation:    crypto.DeriveAESKeys,
+		aeadChanged:      aeadChanged,
+		extensionHandler: newExtensionHandlerClient(params),
+	}, params, nil
 }
 
 func (h *cryptoSetupTLS) HandleCryptoStream(cryptoStream io.ReadWriter) error {

internal/handshake/crypto_setup_tls_test.go

@@ -40,13 +40,11 @@ var _ = Describe("TLS Crypto Setup", func() {
 
 	BeforeEach(func() {
 		aeadChanged = make(chan protocol.EncryptionLevel, 2)
-		csInt, _, err := NewCryptoSetupTLS(
-			"",
-			protocol.PerspectiveServer,
-			protocol.VersionTLS,
+		csInt, _, err := NewCryptoSetupTLSServer(
 			testdata.GetTLSConfig(),
 			&TransportParameters{},
 			aeadChanged,
+			protocol.VersionTLS,
 		)
 		Expect(err).ToNot(HaveOccurred())
 		cs = csInt.(*cryptoSetupTLS)