reject DATAGRAM frames if datagram support is not enabled

internal/wire/frame_parser.go

@@ -13,12 +13,17 @@ import (
 type frameParser struct {
 	ackDelayExponent uint8
 
+	supportsDatagrams bool
+
 	version protocol.VersionNumber
 }
 
 // NewFrameParser creates a new frame parser.
-func NewFrameParser(v protocol.VersionNumber) FrameParser {
-	return &frameParser{version: v}
+func NewFrameParser(supportsDatagrams bool, v protocol.VersionNumber) FrameParser {
+	return &frameParser{
+		supportsDatagrams: supportsDatagrams,
+		version:           v,
+	}
 }
 
 // ParseNextFrame parses the next frame
@@ -88,7 +93,11 @@ func (p *frameParser) parseFrame(r *bytes.Reader, typeByte byte, encLevel protoc
 		case 0x1e:
 			frame, err = parseHandshakeDoneFrame(r, p.version)
 		case 0x30, 0x31:
-			frame, err = parseDatagramFrame(r, p.version)
+			if p.supportsDatagrams {
+				frame, err = parseDatagramFrame(r, p.version)
+				break
+			}
+			fallthrough
 		default:
 			err = errors.New("unknown frame type")
 		}

internal/wire/frame_parser_test.go

@@ -18,7 +18,7 @@ var _ = Describe("Frame parsing", func() {
 
 	BeforeEach(func() {
 		buf = &bytes.Buffer{}
-		parser = NewFrameParser(versionIETFFrames)
+		parser = NewFrameParser(true, versionIETFFrames)
 	})
 
 	It("returns nil if there's nothing more to read", func() {
@@ -280,6 +280,24 @@ var _ = Describe("Frame parsing", func() {
 		Expect(frame).To(Equal(f))
 	})
 
+	It("unpacks DATAGRAM frames", func() {
+		f := &DatagramFrame{Data: []byte("foobar")}
+		buf := &bytes.Buffer{}
+		Expect(f.Write(buf, versionIETFFrames)).To(Succeed())
+		frame, err := parser.ParseNext(bytes.NewReader(buf.Bytes()), protocol.Encryption1RTT)
+		Expect(err).ToNot(HaveOccurred())
+		Expect(frame).To(Equal(f))
+	})
+
+	It("errors when DATAGRAM frames are not supported", func() {
+		parser = NewFrameParser(false, versionIETFFrames)
+		f := &DatagramFrame{Data: []byte("foobar")}
+		buf := &bytes.Buffer{}
+		Expect(f.Write(buf, versionIETFFrames)).To(Succeed())
+		_, err := parser.ParseNext(bytes.NewReader(buf.Bytes()), protocol.Encryption1RTT)
+		Expect(err).To(MatchError("FRAME_ENCODING_ERROR (frame type: 0x30): unknown frame type"))
+	})
+
 	It("errors on invalid type", func() {
 		_, err := parser.ParseNext(bytes.NewReader([]byte{0x42}), protocol.Encryption1RTT)
 		Expect(err).To(MatchError("FRAME_ENCODING_ERROR (frame type: 0x42): unknown frame type"))