add a quic.Config option for DATAGRAM frames

client_test.go

@@ -465,6 +465,7 @@ var _ = Describe("Client", func() {
 					ConnectionIDLength:    13,
 					StatelessResetKey:     []byte("foobar"),
 					TokenStore:            tokenStore,
+					EnableDatagrams:       true,
 				}
 				c := populateClientConfig(config, false)
 				Expect(c.HandshakeTimeout).To(Equal(1337 * time.Minute))
@@ -474,6 +475,7 @@ var _ = Describe("Client", func() {
 				Expect(c.ConnectionIDLength).To(Equal(13))
 				Expect(c.StatelessResetKey).To(Equal([]byte("foobar")))
 				Expect(c.TokenStore).To(Equal(tokenStore))
+				Expect(c.EnableDatagrams).To(BeTrue())
 			})
 
 			It("errors when the Config contains an invalid version", func() {

config.go

@@ -98,6 +98,7 @@ func populateConfig(config *Config) *Config {
 		ConnectionIDLength:                    config.ConnectionIDLength,
 		StatelessResetKey:                     config.StatelessResetKey,
 		TokenStore:                            config.TokenStore,
+		EnableDatagrams:                       config.EnableDatagrams,
 		Tracer:                                config.Tracer,
 	}
 }

config_test.go

@@ -69,6 +69,8 @@ var _ = Describe("Config", func() {
 				f.Set(reflect.ValueOf([]byte{1, 2, 3, 4}))
 			case "KeepAlive":
 				f.Set(reflect.ValueOf(true))
+			case "EnableDatagrams":
+				f.Set(reflect.ValueOf(true))
 			case "Tracer":
 				f.Set(reflect.ValueOf(mocklogging.NewMockTracer(mockCtrl)))
 			default:

interface.go

@@ -259,7 +259,10 @@ type Config struct {
 	StatelessResetKey []byte
 	// KeepAlive defines whether this peer will periodically send a packet to keep the connection alive.
 	KeepAlive bool
-	Tracer    logging.Tracer
+	// See https://datatracker.ietf.org/doc/draft-ietf-quic-datagram/.
+	// Datagrams will only be available when both peers enable datagram support.
+	EnableDatagrams bool
+	Tracer          logging.Tracer
 }
 
 // ConnectionState records basic details about a QUIC connection