implement the disable_migration transport parameter and use it

internal/handshake/tls_extension.go

@@ -16,6 +16,7 @@ const (
 	maxPacketSizeParameterID         transportParameterID = 0x5
 	statelessResetTokenParameterID   transportParameterID = 0x6
 	initialMaxUniStreamsParameterID  transportParameterID = 0x8
+	disableMigrationParameterID      transportParameterID = 0x9
 )
 
 type transportParameter struct {

internal/handshake/transport_parameter_test.go

@@ -132,6 +132,7 @@ var _ = Describe("Transport Parameters", func() {
 					initialMaxUniStreamsParameterID:  {0x44, 0x55},
 					idleTimeoutParameterID:           {0x13, 0x37},
 					maxPacketSizeParameterID:         {0x73, 0x31},
+					disableMigrationParameterID:      {},
 				}
 			})
 			It("reads parameters", func() {
@@ -144,6 +145,7 @@ var _ = Describe("Transport Parameters", func() {
 				Expect(params.IdleTimeout).To(Equal(0x1337 * time.Second))
 				Expect(params.OmitConnectionID).To(BeFalse())
 				Expect(params.MaxPacketSize).To(Equal(protocol.ByteCount(0x7331)))
+				Expect(params.DisableMigration).To(BeTrue())
 			})
 
 			It("rejects the parameters if the initial_max_stream_data is missing", func() {
@@ -215,6 +217,12 @@ var _ = Describe("Transport Parameters", func() {
 				Expect(err).To(MatchError("invalid value for max_packet_size: 1199 (minimum 1200)"))
 			})
 
+			It("rejects the parameters if disable_connection_migration has the wrong length", func() {
+				parameters[disableMigrationParameterID] = []byte{0x11} // should empty
+				_, err := readTransportParameters(paramsMapToList(parameters))
+				Expect(err).To(MatchError("wrong length for disable_migration: 1 (expected empty)"))
+			})
+
 			It("ignores unknown parameters", func() {
 				parameters[1337] = []byte{42}
 				_, err := readTransportParameters(paramsMapToList(parameters))
@@ -240,18 +248,20 @@ var _ = Describe("Transport Parameters", func() {
 					IdleTimeout:                 0xcafe * time.Second,
 					MaxBidiStreams:              0x1234,
 					MaxUniStreams:               0x4321,
+					DisableMigration:            true,
 				}
 			})
 
 			It("creates the parameters list", func() {
 				values := paramsListToMap(params.getTransportParameters())
-				Expect(values).To(HaveLen(6))
+				Expect(values).To(HaveLen(7))
 				Expect(values).To(HaveKeyWithValue(initialMaxStreamDataParameterID, []byte{0xde, 0xad, 0xbe, 0xef}))
 				Expect(values).To(HaveKeyWithValue(initialMaxDataParameterID, []byte{0xde, 0xca, 0xfb, 0xad}))
 				Expect(values).To(HaveKeyWithValue(initialMaxBidiStreamsParameterID, []byte{0x12, 0x34}))
 				Expect(values).To(HaveKeyWithValue(initialMaxUniStreamsParameterID, []byte{0x43, 0x21}))
 				Expect(values).To(HaveKeyWithValue(idleTimeoutParameterID, []byte{0xca, 0xfe}))
 				Expect(values).To(HaveKeyWithValue(maxPacketSizeParameterID, []byte{0x5, 0xac})) // 1452 = 0x5ac
+				Expect(values).To(HaveKeyWithValue(disableMigrationParameterID, []byte{}))
 			})
 		})
 	})

internal/handshake/transport_parameters.go

@@ -28,6 +28,8 @@ type TransportParameters struct {
 
 	OmitConnectionID bool // only used for gQUIC
 	IdleTimeout      time.Duration
+	DisableMigration bool // only used for IETF QUIC
+
 }
 
 // readHelloMap reads the transport parameters from the tags sent in a gQUIC handshake message
@@ -141,6 +143,11 @@ func readTransportParameters(paramsList []transportParameter) (*TransportParamet
 				return nil, fmt.Errorf("invalid value for max_packet_size: %d (minimum 1200)", maxPacketSize)
 			}
 			params.MaxPacketSize = maxPacketSize
+		case disableMigrationParameterID:
+			if len(p.Value) != 0 {
+				return nil, fmt.Errorf("wrong length for disable_migration: %d (expected empty)", len(p.Value))
+			}
+			params.DisableMigration = true
 		}
 	}
 
@@ -173,6 +180,9 @@ func (p *TransportParameters) getTransportParameters() []transportParameter {
 		{idleTimeoutParameterID, idleTimeout},
 		{maxPacketSizeParameterID, maxPacketSize},
 	}
+	if p.DisableMigration {
+		params = append(params, transportParameter{disableMigrationParameterID, nil})
+	}
 	return params
 }