send the transport parameters in the TLS handshake

internal/handshake/tls_extension_handler_client.go

@@ -0,0 +1,81 @@
+package handshake
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/bifurcation/mint"
+	"github.com/bifurcation/mint/syntax"
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+)
+
+type extensionHandlerClient struct {
+	params *paramsNegotiator
+}
+
+var _ mint.AppExtensionHandler = &extensionHandlerClient{}
+
+func newExtensionHandlerClient(params *paramsNegotiator) *extensionHandlerClient {
+	return &extensionHandlerClient{params: params}
+}
+
+func (h *extensionHandlerClient) Send(hType mint.HandshakeType, el *mint.ExtensionList) error {
+	if hType != mint.HandshakeTypeClientHello {
+		return nil
+	}
+
+	data, err := syntax.Marshal(clientHelloTransportParameters{
+		NegotiatedVersion: uint32(protocol.VersionTLS),
+		InitialVersion:    uint32(protocol.VersionTLS),
+		Parameters:        h.params.GetTransportParameters(),
+	})
+	if err != nil {
+		return err
+	}
+	return el.Add(&tlsExtensionBody{data})
+}
+
+func (h *extensionHandlerClient) Receive(hType mint.HandshakeType, el *mint.ExtensionList) error {
+	ext := &tlsExtensionBody{}
+	found := el.Find(ext)
+
+	if hType != mint.HandshakeTypeEncryptedExtensions && hType != mint.HandshakeTypeNewSessionTicket {
+		if found {
+			return fmt.Errorf("Unexpected QUIC extension in handshake message %d", hType)
+		}
+		return nil
+	}
+	if hType == mint.HandshakeTypeNewSessionTicket {
+		// the extension it's optional in the NewSessionTicket message
+		// TODO: handle this
+		return nil
+	}
+
+	// hType == mint.HandshakeTypeEncryptedExtensions
+	if !found {
+		return errors.New("EncryptedExtensions message didn't contain a QUIC extension")
+	}
+
+	eetp := &encryptedExtensionsTransportParameters{}
+	if _, err := syntax.Unmarshal(ext.data, eetp); err != nil {
+		return err
+	}
+	// TODO: check versions
+
+	// check that the server sent the stateless reset token
+	var foundStatelessResetToken bool
+	for _, p := range eetp.Parameters {
+		if p.Parameter == statelessResetTokenParameterID {
+			if len(p.Value) != 16 {
+				return fmt.Errorf("wrong length for stateless_reset_token: %d (expected 16)", len(p.Value))
+			}
+			foundStatelessResetToken = true
+			// TODO: handle this value
+		}
+	}
+	if !foundStatelessResetToken {
+		// TODO: return the right error here
+		return errors.New("server didn't sent stateless_reset_token")
+	}
+	return h.params.SetFromTransportParameters(eetp.Parameters)
+}