move reading of stateless reset tokens to the transport parameter struct

internal/handshake/tls_extension_handler_client.go

@@ -107,25 +107,13 @@ func (h *extensionHandlerClient) Receive(hType mint.HandshakeType, el *mint.Exte
 		}
 	}
 
-	// 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")
-	}
 	params, err := readTransportParameters(eetp.Parameters)
 	if err != nil {
 		return err
 	}
+	if len(params.StatelessResetToken) == 0 {
+		return errors.New("server didn't sent stateless_reset_token")
+	}
 	h.logger.Debugf("Received Transport Parameters: %s", params)
 	h.paramsChan <- *params
 	return nil

internal/handshake/tls_extension_handler_client_test.go

@@ -135,13 +135,6 @@ var _ = Describe("TLS Extension Handler, for the client", func() {
 			Expect(err).To(MatchError("server didn't sent stateless_reset_token"))
 		})
 
-		It("errors if the stateless reset token has the wrong length", func() {
-			parameters[statelessResetTokenParameterID] = bytes.Repeat([]byte{0}, 15) // should be 16
-			addEncryptedExtensionsWithParameters(parameters)
-			err := handler.Receive(mint.HandshakeTypeEncryptedExtensions, &el)
-			Expect(err).To(MatchError("wrong length for stateless_reset_token: 15 (expected 16)"))
-		})
-
 		Context("Version Negotiation", func() {
 			It("accepts a valid version negotiation", func() {
 				done := make(chan struct{})

internal/handshake/tls_extension_handler_server.go

@@ -96,16 +96,14 @@ func (h *extensionHandlerServer) Receive(hType mint.HandshakeType, el *mint.Exte
 		return qerr.Error(qerr.VersionNegotiationMismatch, "Client should have used the initial version")
 	}
 
-	for _, p := range chtp.Parameters {
-		if p.Parameter == statelessResetTokenParameterID {
-			// TODO: return the correct error type
-			return errors.New("client sent a stateless reset token")
-		}
-	}
 	params, err := readTransportParameters(chtp.Parameters)
 	if err != nil {
 		return err
 	}
+	if len(params.StatelessResetToken) != 0 {
+		// TODO: return the correct error type
+		return errors.New("client sent a stateless reset token")
+	}
 	h.logger.Debugf("Received Transport Parameters: %s", params)
 	h.paramsChan <- *params
 	return nil

internal/handshake/tls_extension_handler_server_test.go

@@ -1,6 +1,7 @@
 package handshake
 
 import (
+	"bytes"
 	"fmt"
 
 	"github.com/bifurcation/mint"
@@ -118,7 +119,7 @@ var _ = Describe("TLS Extension Handler, for the server", func() {
 		})
 
 		It("rejects messages that contain a stateless reset token", func() {
-			parameters[statelessResetTokenParameterID] = []byte("reset")
+			parameters[statelessResetTokenParameterID] = bytes.Repeat([]byte{0}, 16)
 			addClientHelloWithParameters(parameters)
 			err := handler.Receive(mint.HandshakeTypeClientHello, &el)
 			Expect(err).To(MatchError("client sent a stateless reset token"))

internal/handshake/transport_parameter_test.go

@@ -1,6 +1,7 @@
 package handshake
 
 import (
+	"bytes"
 	"time"
 
 	"github.com/lucas-clemente/quic-go/internal/protocol"
@@ -122,9 +123,13 @@ var _ = Describe("Transport Parameters", func() {
 		})
 
 		Context("parsing", func() {
-			var parameters map[transportParameterID][]byte
+			var (
+				parameters          map[transportParameterID][]byte
+				statelessResetToken []byte
+			)
 
 			BeforeEach(func() {
+				statelessResetToken = bytes.Repeat([]byte{42}, 16)
 				parameters = map[transportParameterID][]byte{
 					initialMaxStreamDataParameterID:  {0x11, 0x22, 0x33, 0x44},
 					initialMaxDataParameterID:        {0x22, 0x33, 0x44, 0x55},
@@ -133,6 +138,7 @@ var _ = Describe("Transport Parameters", func() {
 					idleTimeoutParameterID:           {0x13, 0x37},
 					maxPacketSizeParameterID:         {0x73, 0x31},
 					disableMigrationParameterID:      {},
+					statelessResetTokenParameterID:   statelessResetToken,
 				}
 			})
 			It("reads parameters", func() {
@@ -146,6 +152,7 @@ var _ = Describe("Transport Parameters", func() {
 				Expect(params.OmitConnectionID).To(BeFalse())
 				Expect(params.MaxPacketSize).To(Equal(protocol.ByteCount(0x7331)))
 				Expect(params.DisableMigration).To(BeTrue())
+				Expect(params.StatelessResetToken).To(Equal(statelessResetToken))
 			})
 
 			It("rejects the parameters if the idle_timeout is missing", func() {
@@ -211,6 +218,12 @@ var _ = Describe("Transport Parameters", func() {
 				Expect(err).To(MatchError("wrong length for disable_migration: 1 (expected empty)"))
 			})
 
+			It("rejects the parameters if the stateless_reset_token has the wrong length", func() {
+				parameters[statelessResetTokenParameterID] = statelessResetToken[1:]
+				_, err := readTransportParameters(paramsMapToList(parameters))
+				Expect(err).To(MatchError("wrong length for stateless_reset_token: 15 (expected 16)"))
+			})
+
 			It("ignores unknown parameters", func() {
 				parameters[1337] = []byte{42}
 				_, err := readTransportParameters(paramsMapToList(parameters))

internal/handshake/transport_parameters.go

@@ -144,6 +144,11 @@ func readTransportParameters(paramsList []transportParameter) (*TransportParamet
 				return nil, fmt.Errorf("wrong length for disable_migration: %d (expected empty)", len(p.Value))
 			}
 			params.DisableMigration = true
+		case statelessResetTokenParameterID:
+			if len(p.Value) != 16 {
+				return nil, fmt.Errorf("wrong length for stateless_reset_token: %d (expected 16)", len(p.Value))
+			}
+			params.StatelessResetToken = p.Value
 		}
 	}