Commit d99f31d8 authored by David Fifield's avatar David Fifield
Browse files

Have encapsulation.ReadData return an error when the buffer is short. 

!154 (comment 2919109)

Still ignoring the io.ErrShortBuffer at the callers, which retains
current behavior.
parent 001f691b

client/lib/turbotunnel.go

+3 −3
Changes for client/lib/turbotunnel.go: 3 added lines, 3 removed lines.
Original line number Diff line number Diff line
@@ -38,10 +38,10 @@ func newEncapsulationPacketConn( 
// ReadFrom reads an encapsulated packet from the stream.

func (c *encapsulationPacketConn) ReadFrom(p []byte) (int, net.Addr, error) {

	n, err := encapsulation.ReadData(c.ReadWriteCloser, p)

	if err != nil {

		return n, c.remoteAddr, err

	if err == io.ErrShortBuffer {

		err = nil

	}

	return n, c.remoteAddr, nil

	return n, c.remoteAddr, err

}



// WriteTo writes an encapsulated packet to the stream.

common/encapsulation/encapsulation.go

+12 −7
Changes for common/encapsulation/encapsulation.go: 12 added lines, 7 removed lines.
Original line number Diff line number Diff line
@@ -53,11 +53,12 @@ var ErrTooLong = errors.New("length prefix is too long") 


// ReadData the next available data chunk, skipping over any padding chunks that

// may come first, and copies the data into p. If p is shorter than the length

// of the data chunk, only the first len(p) bytes are copied into p. The

// returned error value is nil if and only if a data chunk was present and was

// read in its entirety. The returned error is io.EOF only if r ended before the

// first byte of a length prefix. If r ended in the middle of a length prefix or

// data/padding, the returned error is io.ErrUnexpectedEOF.

// of the data chunk, only the first len(p) bytes are copied into p, and the

// error return is io.ErrShortBuffer. The returned error value is nil if and

// only if a data chunk was present and was read in its entirety. The returned

// error is io.EOF only if r ended before the first byte of a length prefix. If

// r ended in the middle of a length prefix or data/padding, the returned error

// is io.ErrUnexpectedEOF.

func ReadData(r io.Reader, p []byte) (int, error) {

	for {

		var b [1]byte
@@ -89,9 +90,13 @@ func ReadData(r io.Reader, p []byte) (int, error) { 
			}

			numData, err := io.ReadFull(r, p)

			if err == nil && numData < n {

				// Discard the rest of the data, if the caller's

				// buffer was too short.

				// If the caller's buffer was too short, discard

				// the rest of the data and return

				// io.ErrShortBuffer.

				_, err = io.CopyN(ioutil.Discard, r, int64(n-numData))

				if err == nil {

					err = io.ErrShortBuffer

				}

			}

			if err == io.EOF {

				err = io.ErrUnexpectedEOF

common/encapsulation/encapsulation_test.go

+6 −6
Changes for common/encapsulation/encapsulation_test.go: 6 added lines, 6 removed lines.
Original line number Diff line number Diff line
@@ -342,8 +342,8 @@ func TestReadDataTruncate(t *testing.T) { 
	var p [4]byte

	// First ReadData should return truncated "1234".

	n, err := ReadData(&enc, p[:])

	if err != nil {

		t.Fatalf("got error %v, expected %v", err, nil)

	if err != io.ErrShortBuffer {

		t.Fatalf("got error %v, expected %v", err, io.ErrShortBuffer)

	}

	if !bytes.Equal(p[:n], []byte("1234")) {

		t.Fatalf("got <%x>, expected <%x>", p[:n], []byte("1234"))
@@ -351,8 +351,8 @@ func TestReadDataTruncate(t *testing.T) { 
	// Second ReadData should return truncated "abcd", not the rest of

	// "12345678".

	n, err = ReadData(&enc, p[:])

	if err != nil {

		t.Fatalf("got error %v, expected %v", err, nil)

	if err != io.ErrShortBuffer {

		t.Fatalf("got error %v, expected %v", err, io.ErrShortBuffer)

	}

	if !bytes.Equal(p[:n], []byte("abcd")) {

		t.Fatalf("got <%x>, expected <%x>", p[:n], []byte("abcd"))
@@ -377,8 +377,8 @@ func TestReadDataTruncateFull(t *testing.T) { 
	}()

	var p [8]byte

	n, err := ReadData(pr, p[:])

	if err != nil {

		t.Fatalf("got error %v, expected %v", err, nil)

	if err != io.ErrShortBuffer {

		t.Fatalf("got error %v, expected %v", err, io.ErrShortBuffer)

	}

	// Should not stop after "hello".

	if !bytes.Equal(p[:n], []byte("hellowor")) {

server/lib/http.go

+3 −0
Changes for server/lib/http.go: 3 added lines, 0 removed lines.
Original line number Diff line number Diff line
@@ -176,6 +176,9 @@ func (handler *httpHandler) turbotunnelMode(conn net.Conn, addr net.Addr) error 
		var p [2048]byte

		for {

			n, err := encapsulation.ReadData(conn, p[:])

			if err == io.ErrShortBuffer {

				err = nil

			}

			if err != nil {

				return

			}