implement a string representation for crypto error

internal/qerr/error_codes.go

@@ -19,7 +19,6 @@ const (
 	VersionNegotiationError ErrorCode = 0x9
 	ProtocolViolation       ErrorCode = 0xa
 	InvalidMigration        ErrorCode = 0xc
-	CryptoError             ErrorCode = 0x100
 )
 
 func (e ErrorCode) Error() string {
@@ -52,9 +51,10 @@ func (e ErrorCode) String() string {
 		return "PROTOCOL_VIOLATION"
 	case InvalidMigration:
 		return "INVALID_MIGRATION"
-	case CryptoError:
-		return "CRYPTO_ERROR"
 	default:
-		return fmt.Sprintf("unknown error code: %d", e)
+		if e >= 0x100 && e < 0x200 {
+			return fmt.Sprintf("CRYPTO_ERROR %d", e-0x100)
+		}
+		return fmt.Sprintf("unknown error code: %#x", uint16(e))
 	}
 }

internal/qerr/errorcodes_test.go

@@ -35,6 +35,6 @@ var _ = Describe("error codes", func() {
 	})
 
 	It("has a string representation for unknown error codes", func() {
-		Expect(ErrorCode(1337).String()).To(Equal("unknown error code: 1337"))
+		Expect(ErrorCode(0x1337).String()).To(Equal("unknown error code: 0x1337"))
 	})
 })

internal/qerr/quic_error.go

@@ -30,6 +30,13 @@ func TimeoutError(errorMessage string) *QuicError {
 	}
 }
 
+// CryptoError create a new QuicError instance for a crypto error
+func CryptoError(tlsAlert uint8) *QuicError {
+	return &QuicError{
+		ErrorCode: 0x100 + ErrorCode(tlsAlert),
+	}
+}
+
 func (e *QuicError) Error() string {
 	if len(e.ErrorMessage) == 0 {
 		return e.ErrorCode.String()

internal/qerr/quic_error_test.go

@@ -25,11 +25,21 @@ var _ = Describe("QUIC Transport Errors", func() {
 		Expect(err.Error()).To(Equal("NO_ERROR: foobar"))
 	})
 
+	It("has a string representation for crypto errors", func() {
+		err := CryptoError(42)
+		Expect(err.Error()).To(Equal("CRYPTO_ERROR 42"))
+	})
+
 	Context("ErrorCode", func() {
 		It("works as error", func() {
 			var err error = StreamStateError
 			Expect(err).To(MatchError("STREAM_STATE_ERROR"))
 		})
+
+		It("recognizes crypto errors", func() {
+			err := ErrorCode(0x100 + 42)
+			Expect(err.Error()).To(Equal("CRYPTO_ERROR 42"))
+		})
 	})
 
 	Context("ToQuicError", func() {