Move frame wrapper

mtproto/wrappers/frame.go

@@ -1,134 +0,0 @@
-package wrappers
-
-import (
-	"bytes"
-	"crypto/aes"
-	"encoding/binary"
-	"hash/crc32"
-	"io"
-	"io/ioutil"
-	"net"
-
-	"github.com/juju/errors"
-
-	"github.com/9seconds/mtg/wrappers"
-)
-
-// Frame: { MessageLength(4) | SequenceNumber(4) | Message(???) | CRC32(4) [| padding(4), ...] }
-const (
-	frameRWCMinMessageLength = 12
-	frameRWCMaxMessageLength = 16777216
-)
-
-var frameRWCPadding = []byte{0x04, 0x00, 0x00, 0x00}
-
-type FrameRWC struct {
-	wrappers.BufferedReader
-
-	conn       wrappers.ReadWriteCloserWithAddr
-	readSeqNo  int32
-	writeSeqNo int32
-}
-
-func (f *FrameRWC) Write(buf []byte) (int, error) {
-	writeBuf := &bytes.Buffer{}
-
-	// 4 - len bytes
-	// 4 - seq bytes
-	// . - message
-	// 4 - crc32
-	messageLength := 4 + 4 + len(buf) + 4
-	paddingLength := (aes.BlockSize - messageLength%aes.BlockSize) % aes.BlockSize
-	writeBuf.Grow(messageLength + paddingLength)
-
-	binary.Write(writeBuf, binary.LittleEndian, uint32(messageLength))
-	binary.Write(writeBuf, binary.LittleEndian, f.writeSeqNo)
-	writeBuf.Write(buf)
-	f.writeSeqNo++
-
-	checksum := crc32.ChecksumIEEE(writeBuf.Bytes())
-	binary.Write(writeBuf, binary.LittleEndian, checksum)
-	writeBuf.Write(bytes.Repeat(frameRWCPadding, paddingLength/4))
-
-	_, err := f.conn.Write(writeBuf.Bytes())
-	return len(buf), err
-}
-
-func (f *FrameRWC) Read(p []byte) (int, error) {
-	return f.BufferedRead(p, func() error {
-		buf := &bytes.Buffer{}
-		sum := crc32.NewIEEE()
-		writer := io.MultiWriter(buf, sum)
-
-		for {
-			buf.Reset()
-			sum.Reset()
-			if _, err := io.CopyN(writer, f.conn, 4); err != nil {
-				return errors.Annotate(err, "Cannot read frame padding")
-			}
-			if !bytes.Equal(buf.Bytes(), frameRWCPadding) {
-				break
-			}
-		}
-
-		messageLength := binary.LittleEndian.Uint32(buf.Bytes())
-		if messageLength%4 != 0 || messageLength < frameRWCMinMessageLength || messageLength > frameRWCMaxMessageLength {
-			return errors.Errorf("Incorrect frame message length %d", messageLength)
-		}
-
-		buf.Reset()
-		buf.Grow(int(messageLength) - 4 - 4)
-		if _, err := io.CopyN(writer, f.conn, int64(messageLength)-4-4); err != nil {
-			return errors.Annotate(err, "Cannot read the message frame")
-		}
-
-		var seqNo int32
-		binary.Read(buf, binary.LittleEndian, &seqNo)
-		if seqNo != f.readSeqNo {
-			return errors.Errorf("Unexpected sequence number %d (wait for %d)", seqNo, f.readSeqNo)
-		}
-		f.readSeqNo++
-
-		data, _ := ioutil.ReadAll(buf)
-		buf.Reset()
-		// write to buf, not to writer. This is because we are going to fetch
-		// crc32 checksum.
-		if _, err := io.CopyN(buf, f.conn, 4); err != nil {
-			return errors.Annotate(err, "Cannot read checksum")
-		}
-		checksum := binary.LittleEndian.Uint32(buf.Bytes())
-
-		if checksum != sum.Sum32() {
-			return errors.Errorf("CRC32 checksum mismatch. Wait for %d, got %d", sum.Sum32(), checksum)
-
-		}
-		f.Buffer.Write(data)
-
-		return nil
-	})
-}
-
-func (f *FrameRWC) Close() error {
-	return f.conn.Close()
-}
-
-func (f *FrameRWC) LocalAddr() *net.TCPAddr {
-	return f.conn.LocalAddr()
-}
-
-func (f *FrameRWC) RemoteAddr() *net.TCPAddr {
-	return f.conn.RemoteAddr()
-}
-
-func (f *FrameRWC) SocketID() string {
-	return f.conn.SocketID()
-}
-
-func NewFrameRWC(conn wrappers.ReadWriteCloserWithAddr, seqNo int32) wrappers.ReadWriteCloserWithAddr {
-	return &FrameRWC{
-		BufferedReader: wrappers.NewBufferedReader(),
-		conn:           conn,
-		readSeqNo:      seqNo,
-		writeSeqNo:     seqNo,
-	}
-}