Merge pull request #2483 from lucas-clemente/qlog-packet-drop-unknown-version

qlog when packets are dropped due to unsupported QUIC version

internal/wire/header.go

@@ -42,7 +42,7 @@ func IsVersionNegotiationPacket(b []byte) bool {
 	return b[0]&0x80 > 0 && b[1] == 0 && b[2] == 0 && b[3] == 0 && b[4] == 0
 }
 
-var errUnsupportedVersion = errors.New("unsupported version")
+var ErrUnsupportedVersion = errors.New("unsupported version")
 
 // The Header is the version independent part of the header
 type Header struct {
@@ -69,8 +69,8 @@ type Header struct {
 func ParsePacket(data []byte, shortHeaderConnIDLen int) (*Header, []byte /* packet data */, []byte /* rest */, error) {
 	hdr, err := parseHeader(bytes.NewReader(data), shortHeaderConnIDLen)
 	if err != nil {
-		if err == errUnsupportedVersion {
-			return hdr, nil, nil, nil
+		if err == ErrUnsupportedVersion {
+			return hdr, nil, nil, ErrUnsupportedVersion
 		}
 		return nil, nil, nil, err
 	}
@@ -160,7 +160,7 @@ func (h *Header) parseLongHeader(b *bytes.Reader) error {
 	}
 	// If we don't understand the version, we have no idea how to interpret the rest of the bytes
 	if !protocol.IsSupportedVersion(protocol.SupportedVersions, h.Version) {
-		return errUnsupportedVersion
+		return ErrUnsupportedVersion
 	}
 
 	switch (h.typeByte & 0x30) >> 4 {

internal/wire/header_test.go

@@ -213,7 +213,7 @@ var _ = Describe("Header Parsing", func() {
 				'f', 'o', 'o', 'b', 'a', 'r', // unspecified bytes
 			}
 			hdr, _, rest, err := ParsePacket(data, 0)
-			Expect(err).ToNot(HaveOccurred())
+			Expect(err).To(MatchError(ErrUnsupportedVersion))
 			Expect(hdr.IsLongHeader).To(BeTrue())
 			Expect(hdr.Version).To(Equal(protocol.VersionNumber(0xdeadbeef)))
 			Expect(hdr.DestConnectionID).To(Equal(protocol.ConnectionID{0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8}))