Direct proxy works

_client/direct.go

@@ -0,0 +1,63 @@
+package client
+
+import (
+	"context"
+	"net"
+	"time"
+
+	"github.com/juju/errors"
+
+	"github.com/9seconds/mtg/antireplay"
+	"github.com/9seconds/mtg/config"
+	"github.com/9seconds/mtg/mtproto"
+	"github.com/9seconds/mtg/obfuscated2"
+	"github.com/9seconds/mtg/wrappers"
+)
+
+const handshakeTimeout = 10 * time.Second
+
+// DirectInit initializes client connection for proxy which connects to
+// Telegram directly.
+func DirectInit(ctx context.Context, cancel context.CancelFunc, socket net.Conn,
+	connID string, antiReplayCache antireplay.Cache,
+	conf *config.Config) (wrappers.Wrap, *mtproto.ConnectionOpts, error) {
+	tcpSocket := socket.(*net.TCPConn)
+	if err := tcpSocket.SetNoDelay(false); err != nil {
+		return nil, nil, errors.Annotate(err, "Cannot disable NO_DELAY to client socket")
+	}
+	if err := tcpSocket.SetReadBuffer(conf.ReadBufferSize); err != nil {
+		return nil, nil, errors.Annotate(err, "Cannot set read buffer size of client socket")
+	}
+	if err := tcpSocket.SetWriteBuffer(conf.WriteBufferSize); err != nil {
+		return nil, nil, errors.Annotate(err, "Cannot set write buffer size of client socket")
+	}
+
+	socket.SetReadDeadline(time.Now().Add(handshakeTimeout)) // nolint: errcheck, gosec
+	frame, err := obfuscated2.ExtractFrame(socket)
+	if err != nil {
+		return nil, nil, errors.Annotate(err, "Cannot extract frame")
+	}
+	socket.SetReadDeadline(time.Time{}) // nolint: errcheck, gosec
+
+	conn := wrappers.NewConn(ctx, cancel, socket, connID, wrappers.ConnPurposeClient, conf.PublicIPv4, conf.PublicIPv6)
+	obfs2, connOpts, err := obfuscated2.ParseObfuscated2ClientFrame(conf.Secret, frame)
+	if err != nil {
+		return nil, nil, errors.Annotate(err, "Cannot parse obfuscated frame")
+	}
+
+	var replayPart = []byte(frame)
+
+	if antiReplayCache.Has(replayPart[4:60]) {
+		return nil, nil, errors.New("Replay attack is detected")
+	}
+	antiReplayCache.Add(replayPart[4:60])
+
+	connOpts.ConnectionProto = mtproto.ConnectionProtocolAny
+	connOpts.ClientAddr = conn.RemoteAddr()
+
+	conn = wrappers.NewStreamCipher(conn, obfs2.Encryptor, obfs2.Decryptor)
+
+	conn.Logger().Infow("Client connection initialized")
+
+	return conn, connOpts, nil
+}