tdlight/td/mtproto/TlsReaderByteFlow.cpp

//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2021
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/mtproto/TlsReaderByteFlow.h"

#include "td/utils/Slice.h"
#include "td/utils/Status.h"

namespace td {
namespace mtproto {

bool TlsReaderByteFlow::loop() {
  if (input_->size() < 5) {
    set_need_size(5);
    return false;
  }

  auto it = input_->clone();
  uint8 buf[5];
  it.advance(5, MutableSlice(buf, 5));
  if (Slice(buf, 3) != Slice("\x17\x03\x03")) {
    close_input(Status::Error("Invalid bytes at the beginning of a packet (emulated tls)"));
    return false;
  }
  size_t len = (buf[3] << 8) | buf[4];
  if (it.size() < len) {
    set_need_size(5 + len);
    return false;
  }

  output_.append(it.cut_head(len));
  *input_ = std::move(it);
  return true;
}

}  // namespace mtproto
}  // namespace td