Proxy is working in a simple mode now

mtglib/internal/obfuscated2/client_handshake.go

@@ -23,16 +23,15 @@ func (c *clientHandhakeFrame) decryptor(secret []byte) cipher.Stream {
 }
 
 func (c *clientHandhakeFrame) encryptor(secret []byte) cipher.Stream {
-	arr := clientHandhakeFrame{}
-	invertByteSlices(arr.data[:], c.data[:])
+	invertedHandshake := c.invert()
 
 	hasher := acquireSha256Hasher()
 	defer releaseSha256Hasher(hasher)
 
-	hasher.Write(arr.key()) // nolint: errcheck
-	hasher.Write(secret)    // nolint: errcheck
+	hasher.Write(invertedHandshake.key()) // nolint: errcheck
+	hasher.Write(secret)                  // nolint: errcheck
 
-	return makeAesCtr(hasher.Sum(nil), arr.iv())
+	return makeAesCtr(hasher.Sum(nil), invertedHandshake.iv())
 }
 
 func ClientHandshake(secret []byte, reader io.Reader) (int, cipher.Stream, cipher.Stream, error) {

mtglib/internal/obfuscated2/handshake_frame.go

@@ -60,3 +60,13 @@ func (h *handshakeFrame) iv() []byte {
 func (h *handshakeFrame) connectionType() []byte {
 	return h.data[handshakeFrameOffsetConnectionType:handshakeFrameOffsetDC]
 }
+
+func (h *handshakeFrame) invert() handshakeFrame {
+	copyFrame := *h
+
+	for i := 0; i < handshakeFrameLenKey+handshakeFrameLenIV; i++ {
+		copyFrame.data[handshakeFrameOffsetKey+i] = h.data[handshakeFrameOffsetConnectionType-1-i]
+	}
+
+	return copyFrame
+}

mtglib/internal/obfuscated2/server_handshake.go

@@ -5,7 +5,7 @@ import (
 	"crypto/rand"
 	"encoding/binary"
 	"fmt"
-	"net"
+	"io"
 )
 
 type serverHandshakeFrame struct {
@@ -13,17 +13,16 @@ type serverHandshakeFrame struct {
 }
 
 func (s *serverHandshakeFrame) decryptor() cipher.Stream {
-	return makeAesCtr(s.key(), s.iv())
+	invertedHandshake := s.invert()
+
+	return makeAesCtr(invertedHandshake.key(), invertedHandshake.iv())
 }
 
 func (s *serverHandshakeFrame) encryptor() cipher.Stream {
-	arr := serverHandshakeFrame{}
-	invertByteSlices(arr.data[:], s.data[:])
-
-	return makeAesCtr(arr.key(), arr.iv())
+	return makeAesCtr(s.key(), s.iv())
 }
 
-func ServerHandshake(conn net.Conn) (cipher.Stream, cipher.Stream, error) {
+func ServerHandshake(writer io.Writer) (cipher.Stream, cipher.Stream, error) {
 	handshake := generateServerHanshakeFrame()
 	copyHandshake := handshake
 	encryptor := handshake.encryptor()
@@ -33,7 +32,7 @@ func ServerHandshake(conn net.Conn) (cipher.Stream, cipher.Stream, error) {
 	copy(handshake.key(), copyHandshake.key())
 	copy(handshake.iv(), copyHandshake.iv())
 
-	if _, err := conn.Write(handshake.data[:]); err != nil {
+	if _, err := writer.Write(handshake.data[:]); err != nil {
 		return nil, nil, fmt.Errorf("cannot send a handshake frame to telegram: %w", err)
 	}
 
@@ -48,16 +47,16 @@ func generateServerHanshakeFrame() serverHandshakeFrame {
 			panic(err)
 		}
 
-		if frame.data[0] == 0xef {
+		if frame.data[0] == 0xef { // nolint: gomnd // taken from tg sources
 			continue
 		}
 
 		switch binary.LittleEndian.Uint32(frame.data[:4]) {
-		case 0x44414548, 0x54534f50, 0x20544547, 0x4954504f, 0xeeeeeeee:
+		case 0x44414548, 0x54534f50, 0x20544547, 0x4954504f, 0xeeeeeeee: // nolint: gomnd // taken from tg sources
 			continue
 		}
 
-		if (frame.data[4] | frame.data[5] | frame.data[6] | frame.data[7]) == 0 {
+		if frame.data[4]|frame.data[5]|frame.data[6]|frame.data[7] == 0 {
 			continue
 		}
 

mtglib/internal/obfuscated2/utils.go

@@ -13,11 +13,3 @@ func makeAesCtr(key, iv []byte) cipher.Stream {
 
 	return cipher.NewCTR(block, iv)
 }
-
-func invertByteSlices(dst, src []byte) {
-	lenDst := len(dst) - 1
-
-	for i, v := range src {
-		dst[lenDst-i] = v
-	}
-}