host/frontend/vnc_server/vnc_client_connection.cpp - device/google/cuttlefish - Git at Google

 /*
  * Copyright (C) 2017 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "host/frontend/vnc_server/vnc_client_connection.h"

 #include <netinet/in.h>
 #include <sys/time.h>

 #include <algorithm>
 #include <cmath>
 #include <cstdint>
 #include <cstring>
 #include <memory>
 #include <mutex>
 #include <string>
 #include <thread>
 #include <utility>
 #include <vector>

 #include <gflags/gflags.h>
 #include <android-base/logging.h>
 #include "common/libs/utils/tcp_socket.h"
 #include "host/frontend/vnc_server/keysyms.h"
 #include "host/frontend/vnc_server/mocks.h"
 #include "host/frontend/vnc_server/vnc_utils.h"
 #include "host/libs/config/cuttlefish_config.h"
 #include "host/libs/screen_connector/screen_connector.h"

 using cuttlefish::Message;
 using cuttlefish::vnc::Stripe;
 using cuttlefish::vnc::StripePtrVec;
 using cuttlefish::vnc::VncClientConnection;

 struct ScreenRegionView {
   using Pixel = uint32_t;
   static constexpr int kSwiftShaderPadding = 4;
   static constexpr int kRedShift = 0;
   static constexpr int kGreenShift = 8;
   static constexpr int kBlueShift = 16;
   static constexpr int kRedBits = 8;
   static constexpr int kGreenBits = 8;
   static constexpr int kBlueBits = 8;
 };

 DEFINE_bool(debug_client, false, "Turn on detailed logging for the client");

 #define DLOG(LEVEL) \
   if (FLAGS_debug_client) LOG(LEVEL)

 namespace {
 class BigEndianChecker {
  public:
   BigEndianChecker() {
     uint32_t u = 1;
     is_big_endian_ = *reinterpret_cast<const char*>(&u) == 0;
   }
   bool operator()() const { return is_big_endian_; }

  private:
   bool is_big_endian_{};
 };

 const BigEndianChecker ImBigEndian;

 constexpr int32_t kDesktopSizeEncoding = -223;
 constexpr int32_t kTightEncoding = 7;

 // These are the lengths not counting the first byte. The first byte
 // indicates the message type.
 constexpr size_t kSetPixelFormatLength = 19;
 constexpr size_t kFramebufferUpdateRequestLength = 9;
 constexpr size_t kSetEncodingsLength = 3;  // more bytes follow
 constexpr size_t kKeyEventLength = 7;
 constexpr size_t kPointerEventLength = 5;
 constexpr size_t kClientCutTextLength = 7;  // more bytes follow

 std::string HostName() {
   auto config = cuttlefish::CuttlefishConfig::Get();
   auto instance = config->ForDefaultInstance();
   return !config || instance.device_title().empty() ? std::string{"localhost"}
                                                     : instance.device_title();
 }

 std::uint16_t uint16_tAt(const void* p) {
   std::uint16_t u{};
   std::memcpy(&u, p, sizeof u);
   return ntohs(u);
 }

 std::uint32_t uint32_tAt(const void* p) {
   std::uint32_t u{};
   std::memcpy(&u, p, sizeof u);
   return ntohl(u);
 }

 std::int32_t int32_tAt(const void* p) {
   std::uint32_t u{};
   std::memcpy(&u, p, sizeof u);
   u = ntohl(u);
   std::int32_t s{};
   std::memcpy(&s, &u, sizeof s);
   return s;
 }

 std::uint32_t RedVal(std::uint32_t pixel) {
   return (pixel >> ScreenRegionView::kRedShift) &
          ((0x1 << ScreenRegionView::kRedBits) - 1);
 }

 std::uint32_t BlueVal(std::uint32_t pixel) {
   return (pixel >> ScreenRegionView::kBlueShift) &
          ((0x1 << ScreenRegionView::kBlueBits) - 1);
 }

 std::uint32_t GreenVal(std::uint32_t pixel) {
   return (pixel >> ScreenRegionView::kGreenShift) &
          ((0x1 << ScreenRegionView::kGreenBits) - 1);
 }
 }  // namespace
 namespace cuttlefish {
 namespace vnc {
 bool operator==(const VncClientConnection::FrameBufferUpdateRequest& lhs,
                 const VncClientConnection::FrameBufferUpdateRequest& rhs) {
   return lhs.x_pos == rhs.x_pos && lhs.y_pos == rhs.y_pos &&
          lhs.width == rhs.width && lhs.height == rhs.height;
 }

 bool operator!=(const VncClientConnection::FrameBufferUpdateRequest& lhs,
                 const VncClientConnection::FrameBufferUpdateRequest& rhs) {
   return !(lhs == rhs);
 }
 }  // namespace vnc
 }  // namespace cuttlefish

 VncClientConnection::VncClientConnection(
     ClientSocket client, std::shared_ptr<VirtualInputs> virtual_inputs,
     BlackBoard* bb, bool aggressive)
     : client_{std::move(client)}, virtual_inputs_{virtual_inputs}, bb_{bb} {
   frame_buffer_request_handler_tid_ = std::thread(
       &VncClientConnection::FrameBufferUpdateRequestHandler, this, aggressive);
 }

 VncClientConnection::~VncClientConnection() {
   {
     std::lock_guard<std::mutex> guard(m_);
     closed_ = true;
   }
   bb_->StopWaiting(this);
   frame_buffer_request_handler_tid_.join();
 }

 void VncClientConnection::StartSession() {
   LOG(INFO) << "Starting session";
   SetupProtocol();
   LOG(INFO) << "Protocol set up";
   if (client_.closed()) {
     return;
   }
   SetupSecurityType();
   LOG(INFO) << "Security type set";
   if (client_.closed()) {
     return;
   }
   GetClientInit();
   LOG(INFO) << "Gotten client init";
   if (client_.closed()) {
     return;
   }
   SendServerInit();
   LOG(INFO) << "Sent server init";
   if (client_.closed()) {
     return;
   }
   NormalSession();
   LOG(INFO) << "vnc session terminated";
 }

 bool VncClientConnection::closed() {
   std::lock_guard<std::mutex> guard(m_);
   return closed_;
 }

 void VncClientConnection::SetupProtocol() {
   static constexpr char kRFBVersion[] = "RFB 003.008\n";
   static constexpr char kRFBVersionOld[] = "RFB 003.003\n";
   static constexpr auto kVersionLen = (sizeof kRFBVersion) - 1;
   client_.SendNoSignal(reinterpret_cast<const std::uint8_t*>(kRFBVersion),
                        kVersionLen);
   auto client_protocol = client_.Recv(kVersionLen);
   if (std::memcmp(&client_protocol[0], kRFBVersion,
                   std::min(kVersionLen, client_protocol.size())) != 0) {
     if (!std::memcmp(
                 &client_protocol[0],
                 kRFBVersionOld,
                 std::min(kVersionLen, client_protocol.size()))) {
         // We'll deal with V3.3 as well.
         client_is_old_ = true;
         return;
     }

     client_protocol.push_back('\0');
     LOG(ERROR) << "vnc client wants a different protocol: "
                << reinterpret_cast<const char*>(&client_protocol[0]);
   }
 }

 void VncClientConnection::SetupSecurityType() {
   if (client_is_old_) {
     static constexpr std::uint8_t kVNCSecurity[4] = { 0x00, 0x00, 0x00, 0x02 };
     client_.SendNoSignal(kVNCSecurity);

     static constexpr std::uint8_t kChallenge[16] =
         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

     client_.SendNoSignal(kChallenge);

     auto clientResponse = client_.Recv(16);
     (void)clientResponse;  // Accept any response, we're not interested in actual security.

     static constexpr std::uint8_t kSuccess[4] = { 0x00, 0x00, 0x00, 0x00 };
     client_.SendNoSignal(kSuccess);
     return;
   }

   static constexpr std::uint8_t kNoneSecurity = 0x1;
   // The first '0x1' indicates the number of items that follow
   static constexpr std::uint8_t kOnlyNoneSecurity[] = {0x01, kNoneSecurity};
   client_.SendNoSignal(kOnlyNoneSecurity);
   auto client_security = client_.Recv(1);
   if (client_.closed()) {
     return;
   }
   if (client_security.front() != kNoneSecurity) {
     LOG(ERROR) << "vnc client is asking for security type "
                << static_cast<int>(client_security.front());
   }
   static constexpr std::uint8_t kZero[4] = {};
   client_.SendNoSignal(kZero);
 }

 void VncClientConnection::GetClientInit() {
   auto client_shared = client_.Recv(1);
 }

 void VncClientConnection::SendServerInit() {
   const std::string server_name = HostName();
   std::lock_guard<std::mutex> guard(m_);
   auto server_init = cuttlefish::CreateMessage(
       static_cast<std::uint16_t>(ScreenWidth()),
       static_cast<std::uint16_t>(ScreenHeight()), pixel_format_.bits_per_pixel,
       pixel_format_.depth, pixel_format_.big_endian, pixel_format_.true_color,
       pixel_format_.red_max, pixel_format_.green_max, pixel_format_.blue_max,
       pixel_format_.red_shift, pixel_format_.green_shift,
       pixel_format_.blue_shift, std::uint16_t{},  // padding
       std::uint8_t{},                             // padding
       static_cast<std::uint32_t>(server_name.size()), server_name);
   client_.SendNoSignal(server_init);
 }

 Message VncClientConnection::MakeFrameBufferUpdateHeader(
     std::uint16_t num_stripes) {
   return cuttlefish::CreateMessage(std::uint8_t{0},  // message-type
                             std::uint8_t{},   // padding
                             std::uint16_t{num_stripes});
 }

 void VncClientConnection::AppendRawStripeHeader(Message* frame_buffer_update,
                                                 const Stripe& stripe) {
   static constexpr int32_t kRawEncoding = 0;
   cuttlefish::AppendToMessage(frame_buffer_update, std::uint16_t{stripe.x},
                        std::uint16_t{stripe.y}, std::uint16_t{stripe.width},
                        std::uint16_t{stripe.height}, kRawEncoding);
 }

 void VncClientConnection::AppendJpegSize(Message* frame_buffer_update,
                                          size_t jpeg_size) {
   constexpr size_t kJpegSizeOneByteMax = 127;
   constexpr size_t kJpegSizeTwoByteMax = 16383;
   constexpr size_t kJpegSizeThreeByteMax = 4194303;

   if (jpeg_size <= kJpegSizeOneByteMax) {
     cuttlefish::AppendToMessage(frame_buffer_update,
                          static_cast<std::uint8_t>(jpeg_size));
   } else if (jpeg_size <= kJpegSizeTwoByteMax) {
     auto sz = static_cast<std::uint32_t>(jpeg_size);
     cuttlefish::AppendToMessage(frame_buffer_update,
                          static_cast<std::uint8_t>((sz & 0x7F) | 0x80),
                          static_cast<std::uint8_t>((sz >> 7) & 0xFF));
   } else {
     if (jpeg_size > kJpegSizeThreeByteMax) {
       LOG(FATAL) << "jpeg size is too big: " << jpeg_size << " must be under "
                  << kJpegSizeThreeByteMax;
     }
     const auto sz = static_cast<std::uint32_t>(jpeg_size);
     cuttlefish::AppendToMessage(frame_buffer_update,
                          static_cast<std::uint8_t>((sz & 0x7F) | 0x80),
                          static_cast<std::uint8_t>(((sz >> 7) & 0x7F) | 0x80),
                          static_cast<std::uint8_t>((sz >> 14) & 0xFF));
   }
 }

 void VncClientConnection::AppendRawStripe(Message* frame_buffer_update,
                                           const Stripe& stripe) const {
   using Pixel = ScreenRegionView::Pixel;
   auto& fbu = *frame_buffer_update;
   AppendRawStripeHeader(&fbu, stripe);
   auto init_size = fbu.size();
   fbu.insert(fbu.end(), stripe.raw_data.begin(), stripe.raw_data.end());
   for (size_t i = init_size; i < fbu.size(); i += sizeof(Pixel)) {
     CHECK_LE(i + sizeof(Pixel), fbu.size());
     Pixel raw_pixel{};
     std::memcpy(&raw_pixel, &fbu[i], sizeof raw_pixel);
     auto red = RedVal(raw_pixel);
     auto green = GreenVal(raw_pixel);
     auto blue = BlueVal(raw_pixel);
     Pixel pixel = Pixel{red} << pixel_format_.red_shift |
                   Pixel{blue} << pixel_format_.blue_shift |
                   Pixel{green} << pixel_format_.green_shift;

     if (bool(pixel_format_.big_endian) != ImBigEndian()) {
       // flip them bits (refactor into function)
       auto p = reinterpret_cast<char*>(&pixel);
       std::swap(p[0], p[3]);
       std::swap(p[1], p[2]);
     }
     std::memcpy(&fbu[i], &pixel, sizeof pixel);
   }
 }

 Message VncClientConnection::MakeRawFrameBufferUpdate(
     const StripePtrVec& stripes) const {
   auto fbu =
       MakeFrameBufferUpdateHeader(static_cast<std::uint16_t>(stripes.size()));
   for (auto& stripe : stripes) {
     AppendRawStripe(&fbu, *stripe);
   }
   return fbu;
 }

 void VncClientConnection::AppendJpegStripeHeader(Message* frame_buffer_update,
                                                  const Stripe& stripe) {
   static constexpr std::uint8_t kJpegEncoding = 0x90;
   cuttlefish::AppendToMessage(frame_buffer_update, stripe.x, stripe.y, stripe.width,
                        stripe.height, kTightEncoding, kJpegEncoding);
   AppendJpegSize(frame_buffer_update, stripe.jpeg_data.size());
 }

 void VncClientConnection::AppendJpegStripe(Message* frame_buffer_update,
                                            const Stripe& stripe) {
   AppendJpegStripeHeader(frame_buffer_update, stripe);
   frame_buffer_update->insert(frame_buffer_update->end(),
                               stripe.jpeg_data.begin(), stripe.jpeg_data.end());
 }

 Message VncClientConnection::MakeJpegFrameBufferUpdate(
     const StripePtrVec& stripes) {
   auto fbu =
       MakeFrameBufferUpdateHeader(static_cast<std::uint16_t>(stripes.size()));
   for (auto& stripe : stripes) {
     AppendJpegStripe(&fbu, *stripe);
   }
   return fbu;
 }

 Message VncClientConnection::MakeFrameBufferUpdate(
     const StripePtrVec& stripes) {
   return use_jpeg_compression_ ? MakeJpegFrameBufferUpdate(stripes)
                                : MakeRawFrameBufferUpdate(stripes);
 }

 void VncClientConnection::FrameBufferUpdateRequestHandler(bool aggressive) {
   BlackBoard::Registerer reg(bb_, this);

   while (!closed()) {
     auto stripes = bb_->WaitForSenderWork(this);
     if (closed()) {
       break;
     }
     if (stripes.empty()) {
       LOG(FATAL) << "Got 0 stripes";
     }
     {
       // lock here so a portrait frame can't be sent after a landscape
       // DesktopSize update, or vice versa.
       std::lock_guard<std::mutex> guard(m_);
       DLOG(INFO) << "Sending update in "
                  << (current_orientation_ == ScreenOrientation::Portrait
                          ? "portrait"
                          : "landscape")
                  << " mode";
       client_.SendNoSignal(MakeFrameBufferUpdate(stripes));
     }
     if (aggressive) {
       bb_->FrameBufferUpdateRequestReceived(this);
     }
   }
 }

 void VncClientConnection::SendDesktopSizeUpdate() {
   static constexpr int32_t kDesktopSizeEncoding = -223;
   client_.SendNoSignal(cuttlefish::CreateMessage(
       std::uint8_t{0},   // message-type,
       std::uint8_t{},    // padding
       std::uint16_t{1},  // one pseudo rectangle
       std::uint16_t{0}, std::uint16_t{0},
       static_cast<std::uint16_t>(ScreenWidth()),
       static_cast<std::uint16_t>(ScreenHeight()), kDesktopSizeEncoding));
 }

 bool VncClientConnection::IsUrgent(
     const FrameBufferUpdateRequest& update_request) const {
   return !update_request.incremental ||
          update_request != previous_update_request_;
 }

 void VncClientConnection::HandleFramebufferUpdateRequest() {
   auto msg = client_.Recv(kFramebufferUpdateRequestLength);
   if (msg.size() != kFramebufferUpdateRequestLength) {
     return;
   }
   FrameBufferUpdateRequest fbur{msg[1] == 0, uint16_tAt(&msg[1]),
                                 uint16_tAt(&msg[3]), uint16_tAt(&msg[5]),
                                 uint16_tAt(&msg[7])};
   if (IsUrgent(fbur)) {
     bb_->SignalClientNeedsEntireScreen(this);
   }
   bb_->FrameBufferUpdateRequestReceived(this);
   previous_update_request_ = fbur;
 }

 void VncClientConnection::HandleSetEncodings() {
   auto msg = client_.Recv(kSetEncodingsLength);
   if (msg.size() != kSetEncodingsLength) {
     return;
   }
   auto count = uint16_tAt(&msg[1]);
   auto encodings = client_.Recv(count * sizeof(int32_t));
   if (encodings.size() % sizeof(int32_t) != 0) {
     return;
   }
   {
     std::lock_guard<std::mutex> guard(m_);
     use_jpeg_compression_ = false;
   }
   for (size_t i = 0; i < encodings.size(); i += sizeof(int32_t)) {
     auto enc = int32_tAt(&encodings[i]);
     DLOG(INFO) << "client requesting encoding: " << enc;
     if (enc == kTightEncoding) {
       // This is a deviation from the spec which says that if a jpeg quality
       // level is not specified, tight encoding won't use jpeg.
       std::lock_guard<std::mutex> guard(m_);
       use_jpeg_compression_ = true;
     }
     if (kJpegMinQualityEncoding <= enc && enc <= kJpegMaxQualityEncoding) {
       DLOG(INFO) << "jpeg compression level: " << enc;
       bb_->set_jpeg_quality_level(enc);
     }
     if (enc == kDesktopSizeEncoding) {
       supports_desktop_size_encoding_ = true;
     }
   }
 }

 void VncClientConnection::HandleSetPixelFormat() {
   std::lock_guard<std::mutex> guard(m_);
   auto msg = client_.Recv(kSetPixelFormatLength);
   if (msg.size() != kSetPixelFormatLength) {
     return;
   }
   pixel_format_.bits_per_pixel = msg[3];
   pixel_format_.depth = msg[4];
   pixel_format_.big_endian = msg[5];
   pixel_format_.true_color = msg[7];
   pixel_format_.red_max = uint16_tAt(&msg[8]);
   pixel_format_.green_max = uint16_tAt(&msg[10]);
   pixel_format_.blue_max = uint16_tAt(&msg[12]);
   pixel_format_.red_shift = msg[13];
   pixel_format_.green_shift = msg[14];
   pixel_format_.blue_shift = msg[15];
 }

 void VncClientConnection::HandlePointerEvent() {
   auto msg = client_.Recv(kPointerEventLength);
   if (msg.size() != kPointerEventLength) {
     return;
   }
   std::uint8_t button_mask = msg[0];
   auto x_pos = uint16_tAt(&msg[1]);
   auto y_pos = uint16_tAt(&msg[3]);
   {
     std::lock_guard<std::mutex> guard(m_);
     if (current_orientation_ == ScreenOrientation::Landscape) {
       std::tie(x_pos, y_pos) =
           std::make_pair(ScreenConnectorInfo::ScreenWidth(0) - y_pos, x_pos);
     }
   }
   virtual_inputs_->HandlePointerEvent(button_mask, x_pos, y_pos);
 }

 void VncClientConnection::UpdateAccelerometer(float /*x*/, float /*y*/,
                                               float /*z*/) {
   // TODO(jemoreira): Implement when vsoc sensor hal is updated
 }

 VncClientConnection::Coordinates VncClientConnection::CoordinatesForOrientation(
     ScreenOrientation orientation) const {
   // Compute the acceleration vector that we need to send to mimic
   // this change.
   constexpr float g = 9.81;
   constexpr float angle = 20.0;
   const float cos_angle = std::cos(angle / M_PI);
   const float sin_angle = std::sin(angle / M_PI);
   const float z = g * sin_angle;
   switch (orientation) {
     case ScreenOrientation::Portrait:
       return {0, g * cos_angle, z};
     case ScreenOrientation::Landscape:
       return {g * cos_angle, 0, z};
   }
 }

 int VncClientConnection::ScreenWidth() const {
   return current_orientation_ == ScreenOrientation::Portrait
              ? ScreenConnectorInfo::ScreenWidth(0)
              : ScreenConnectorInfo::ScreenHeight(0);
 }

 int VncClientConnection::ScreenHeight() const {
   return current_orientation_ == ScreenOrientation::Portrait
              ? ScreenConnectorInfo::ScreenHeight(0)
              : ScreenConnectorInfo::ScreenWidth(0);
 }

 void VncClientConnection::SetScreenOrientation(ScreenOrientation orientation) {
   std::lock_guard<std::mutex> guard(m_);
   auto coords = CoordinatesForOrientation(orientation);
   UpdateAccelerometer(coords.x, coords.y, coords.z);
   if (supports_desktop_size_encoding_) {
     auto previous_orientation = current_orientation_;
     current_orientation_ = orientation;
     if (current_orientation_ != previous_orientation &&
         supports_desktop_size_encoding_) {
       SendDesktopSizeUpdate();
       bb_->SetOrientation(this, current_orientation_);
       // TODO not sure if I should be sending a frame update along with this,
       // or just letting the next FBUR handle it. This seems to me like it's
       // sending one more frame buffer update than was requested, which is
       // maybe a violation of the spec?
     }
   }
 }

 bool VncClientConnection::RotateIfIsRotationCommand(std::uint32_t key) {
   // Due to different configurations on different platforms we're supporting
   // a set of options for rotating the screen. These are similar to what
   // the emulator supports and has supported.
   // ctrl+left and ctrl+right work on windows and linux
   // command+left and command+right work on Mac
   // ctrl+fn+F11 and ctrl+fn+F12 work when chromoting to ubuntu from a Mac
   if (!control_key_down_ && !meta_key_down_) {
     return false;
   }
   switch (key) {
     case cuttlefish::xk::Right:
     case cuttlefish::xk::F12:
       DLOG(INFO) << "switching to portrait";
       SetScreenOrientation(ScreenOrientation::Portrait);
       break;
     case cuttlefish::xk::Left:
     case cuttlefish::xk::F11:
       DLOG(INFO) << "switching to landscape";
       SetScreenOrientation(ScreenOrientation::Landscape);
       break;
     default:
       return false;
   }
   return true;
 }

 void VncClientConnection::HandleKeyEvent() {
   auto msg = client_.Recv(kKeyEventLength);
   if (msg.size() != kKeyEventLength) {
     return;
   }

   auto key = uint32_tAt(&msg[3]);
   bool key_down = msg[0];
   switch (key) {
     case cuttlefish::xk::ControlLeft:
     case cuttlefish::xk::ControlRight:
       control_key_down_ = key_down;
       break;
     case cuttlefish::xk::MetaLeft:
     case cuttlefish::xk::MetaRight:
       meta_key_down_ = key_down;
       break;
     case cuttlefish::xk::F5:
       key = cuttlefish::xk::Menu;
       break;
     case cuttlefish::xk::F7:
       virtual_inputs_->PressPowerButton(key_down);
       return;
     default:
       break;
   }

   if (RotateIfIsRotationCommand(key)) {
     return;
   }

   virtual_inputs_->GenerateKeyPressEvent(key, key_down);
 }

 void VncClientConnection::HandleClientCutText() {
   auto msg = client_.Recv(kClientCutTextLength);
   if (msg.size() != kClientCutTextLength) {
     return;
   }
   auto len = uint32_tAt(&msg[3]);
   client_.Recv(len);
 }

 void VncClientConnection::NormalSession() {
   static constexpr std::uint8_t kSetPixelFormatMessage{0};
   static constexpr std::uint8_t kSetEncodingsMessage{2};
   static constexpr std::uint8_t kFramebufferUpdateRequestMessage{3};
   static constexpr std::uint8_t kKeyEventMessage{4};
   static constexpr std::uint8_t kPointerEventMessage{5};
   static constexpr std::uint8_t kClientCutTextMessage{6};
   while (true) {
     if (client_.closed()) {
       return;
     }
     auto msg = client_.Recv(1);
     if (client_.closed()) {
       return;
     }
     auto msg_type = msg.front();
     DLOG(INFO) << "Received message type " << msg_type;

     switch (msg_type) {
       case kSetPixelFormatMessage:
         HandleSetPixelFormat();
         break;

       case kSetEncodingsMessage:
         HandleSetEncodings();
         break;

       case kFramebufferUpdateRequestMessage:
         HandleFramebufferUpdateRequest();
         break;

       case kKeyEventMessage:
         HandleKeyEvent();
         break;

       case kPointerEventMessage:
         HandlePointerEvent();
         break;

       case kClientCutTextMessage:
         HandleClientCutText();
         break;

       default:
         LOG(WARNING) << "message type not handled: "
                      << static_cast<int>(msg_type);
         break;
     }
   }
 }
	/*
	* Copyright (C) 2017 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "host/frontend/vnc_server/vnc_client_connection.h"

	#include <netinet/in.h>
	#include <sys/time.h>

	#include <algorithm>
	#include <cmath>
	#include <cstdint>
	#include <cstring>
	#include <memory>
	#include <mutex>
	#include <string>
	#include <thread>
	#include <utility>
	#include <vector>

	#include <gflags/gflags.h>
	#include <android-base/logging.h>
	#include "common/libs/utils/tcp_socket.h"
	#include "host/frontend/vnc_server/keysyms.h"
	#include "host/frontend/vnc_server/mocks.h"
	#include "host/frontend/vnc_server/vnc_utils.h"
	#include "host/libs/config/cuttlefish_config.h"
	#include "host/libs/screen_connector/screen_connector.h"

	using cuttlefish::Message;
	using cuttlefish::vnc::Stripe;
	using cuttlefish::vnc::StripePtrVec;
	using cuttlefish::vnc::VncClientConnection;

	struct ScreenRegionView {
	using Pixel = uint32_t;
	static constexpr int kSwiftShaderPadding = 4;
	static constexpr int kRedShift = 0;
	static constexpr int kGreenShift = 8;
	static constexpr int kBlueShift = 16;
	static constexpr int kRedBits = 8;
	static constexpr int kGreenBits = 8;
	static constexpr int kBlueBits = 8;
	};

	DEFINE_bool(debug_client, false, "Turn on detailed logging for the client");

	#define DLOG(LEVEL) \
	if (FLAGS_debug_client) LOG(LEVEL)

	namespace {
	class BigEndianChecker {
	public:
	BigEndianChecker() {
	uint32_t u = 1;
	is_big_endian_ = reinterpret_cast<const char>(&u) == 0;
	}
	bool operator()() const { return is_big_endian_; }

	private:
	bool is_big_endian_{};
	};

	const BigEndianChecker ImBigEndian;

	constexpr int32_t kDesktopSizeEncoding = -223;
	constexpr int32_t kTightEncoding = 7;

	// These are the lengths not counting the first byte. The first byte
	// indicates the message type.
	constexpr size_t kSetPixelFormatLength = 19;
	constexpr size_t kFramebufferUpdateRequestLength = 9;
	constexpr size_t kSetEncodingsLength = 3; // more bytes follow
	constexpr size_t kKeyEventLength = 7;
	constexpr size_t kPointerEventLength = 5;
	constexpr size_t kClientCutTextLength = 7; // more bytes follow

	std::string HostName() {
	auto config = cuttlefish::CuttlefishConfig::Get();
	auto instance = config->ForDefaultInstance();
	return !config \|\| instance.device_title().empty() ? std::string{"localhost"}
	: instance.device_title();
	}

	std::uint16_t uint16_tAt(const void* p) {
	std::uint16_t u{};
	std::memcpy(&u, p, sizeof u);
	return ntohs(u);
	}

	std::uint32_t uint32_tAt(const void* p) {
	std::uint32_t u{};
	std::memcpy(&u, p, sizeof u);
	return ntohl(u);
	}

	std::int32_t int32_tAt(const void* p) {
	std::uint32_t u{};
	std::memcpy(&u, p, sizeof u);
	u = ntohl(u);
	std::int32_t s{};
	std::memcpy(&s, &u, sizeof s);
	return s;
	}

	std::uint32_t RedVal(std::uint32_t pixel) {
	return (pixel >> ScreenRegionView::kRedShift) &
	((0x1 << ScreenRegionView::kRedBits) - 1);
	}

	std::uint32_t BlueVal(std::uint32_t pixel) {
	return (pixel >> ScreenRegionView::kBlueShift) &
	((0x1 << ScreenRegionView::kBlueBits) - 1);
	}

	std::uint32_t GreenVal(std::uint32_t pixel) {
	return (pixel >> ScreenRegionView::kGreenShift) &
	((0x1 << ScreenRegionView::kGreenBits) - 1);
	}
	} // namespace
	namespace cuttlefish {
	namespace vnc {
	bool operator==(const VncClientConnection::FrameBufferUpdateRequest& lhs,
	const VncClientConnection::FrameBufferUpdateRequest& rhs) {
	return lhs.x_pos == rhs.x_pos && lhs.y_pos == rhs.y_pos &&
	lhs.width == rhs.width && lhs.height == rhs.height;
	}

	bool operator!=(const VncClientConnection::FrameBufferUpdateRequest& lhs,
	const VncClientConnection::FrameBufferUpdateRequest& rhs) {
	return !(lhs == rhs);
	}
	} // namespace vnc
	} // namespace cuttlefish

	VncClientConnection::VncClientConnection(
	ClientSocket client, std::shared_ptr<VirtualInputs> virtual_inputs,
	BlackBoard* bb, bool aggressive)
	: client_{std::move(client)}, virtual_inputs_{virtual_inputs}, bb_{bb} {
	frame_buffer_request_handler_tid_ = std::thread(
	&VncClientConnection::FrameBufferUpdateRequestHandler, this, aggressive);
	}

	VncClientConnection::~VncClientConnection() {
	{
	std::lock_guard<std::mutex> guard(m_);
	closed_ = true;
	}
	bb_->StopWaiting(this);
	frame_buffer_request_handler_tid_.join();
	}

	void VncClientConnection::StartSession() {
	LOG(INFO) << "Starting session";
	SetupProtocol();
	LOG(INFO) << "Protocol set up";
	if (client_.closed()) {
	return;
	}
	SetupSecurityType();
	LOG(INFO) << "Security type set";
	if (client_.closed()) {
	return;
	}
	GetClientInit();
	LOG(INFO) << "Gotten client init";
	if (client_.closed()) {
	return;
	}
	SendServerInit();
	LOG(INFO) << "Sent server init";
	if (client_.closed()) {
	return;
	}
	NormalSession();
	LOG(INFO) << "vnc session terminated";
	}

	bool VncClientConnection::closed() {
	std::lock_guard<std::mutex> guard(m_);
	return closed_;
	}

	void VncClientConnection::SetupProtocol() {
	static constexpr char kRFBVersion[] = "RFB 003.008\n";
	static constexpr char kRFBVersionOld[] = "RFB 003.003\n";
	static constexpr auto kVersionLen = (sizeof kRFBVersion) - 1;
	client_.SendNoSignal(reinterpret_cast<const std::uint8_t*>(kRFBVersion),
	kVersionLen);
	auto client_protocol = client_.Recv(kVersionLen);
	if (std::memcmp(&client_protocol[0], kRFBVersion,
	std::min(kVersionLen, client_protocol.size())) != 0) {
	if (!std::memcmp(
	&client_protocol[0],
	kRFBVersionOld,
	std::min(kVersionLen, client_protocol.size()))) {
	// We'll deal with V3.3 as well.
	client_is_old_ = true;
	return;
	}

	client_protocol.push_back('\0');
	LOG(ERROR) << "vnc client wants a different protocol: "
	<< reinterpret_cast<const char*>(&client_protocol[0]);
	}
	}

	void VncClientConnection::SetupSecurityType() {
	if (client_is_old_) {
	static constexpr std::uint8_t kVNCSecurity[4] = { 0x00, 0x00, 0x00, 0x02 };
	client_.SendNoSignal(kVNCSecurity);

	static constexpr std::uint8_t kChallenge[16] =
	{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

	client_.SendNoSignal(kChallenge);

	auto clientResponse = client_.Recv(16);
	(void)clientResponse; // Accept any response, we're not interested in actual security.

	static constexpr std::uint8_t kSuccess[4] = { 0x00, 0x00, 0x00, 0x00 };
	client_.SendNoSignal(kSuccess);
	return;
	}

	static constexpr std::uint8_t kNoneSecurity = 0x1;
	// The first '0x1' indicates the number of items that follow
	static constexpr std::uint8_t kOnlyNoneSecurity[] = {0x01, kNoneSecurity};
	client_.SendNoSignal(kOnlyNoneSecurity);
	auto client_security = client_.Recv(1);
	if (client_.closed()) {
	return;
	}
	if (client_security.front() != kNoneSecurity) {
	LOG(ERROR) << "vnc client is asking for security type "
	<< static_cast<int>(client_security.front());
	}
	static constexpr std::uint8_t kZero[4] = {};
	client_.SendNoSignal(kZero);
	}

	void VncClientConnection::GetClientInit() {
	auto client_shared = client_.Recv(1);
	}

	void VncClientConnection::SendServerInit() {
	const std::string server_name = HostName();
	std::lock_guard<std::mutex> guard(m_);
	auto server_init = cuttlefish::CreateMessage(
	static_cast<std::uint16_t>(ScreenWidth()),
	static_cast<std::uint16_t>(ScreenHeight()), pixel_format_.bits_per_pixel,
	pixel_format_.depth, pixel_format_.big_endian, pixel_format_.true_color,
	pixel_format_.red_max, pixel_format_.green_max, pixel_format_.blue_max,
	pixel_format_.red_shift, pixel_format_.green_shift,
	pixel_format_.blue_shift, std::uint16_t{}, // padding
	std::uint8_t{}, // padding
	static_cast<std::uint32_t>(server_name.size()), server_name);
	client_.SendNoSignal(server_init);
	}

	Message VncClientConnection::MakeFrameBufferUpdateHeader(
	std::uint16_t num_stripes) {
	return cuttlefish::CreateMessage(std::uint8_t{0}, // message-type
	std::uint8_t{}, // padding
	std::uint16_t{num_stripes});
	}

	void VncClientConnection::AppendRawStripeHeader(Message* frame_buffer_update,
	const Stripe& stripe) {
	static constexpr int32_t kRawEncoding = 0;
	cuttlefish::AppendToMessage(frame_buffer_update, std::uint16_t{stripe.x},
	std::uint16_t{stripe.y}, std::uint16_t{stripe.width},
	std::uint16_t{stripe.height}, kRawEncoding);
	}

	void VncClientConnection::AppendJpegSize(Message* frame_buffer_update,
	size_t jpeg_size) {
	constexpr size_t kJpegSizeOneByteMax = 127;
	constexpr size_t kJpegSizeTwoByteMax = 16383;
	constexpr size_t kJpegSizeThreeByteMax = 4194303;

	if (jpeg_size <= kJpegSizeOneByteMax) {
	cuttlefish::AppendToMessage(frame_buffer_update,
	static_cast<std::uint8_t>(jpeg_size));
	} else if (jpeg_size <= kJpegSizeTwoByteMax) {
	auto sz = static_cast<std::uint32_t>(jpeg_size);
	cuttlefish::AppendToMessage(frame_buffer_update,
	static_cast<std::uint8_t>((sz & 0x7F) \| 0x80),
	static_cast<std::uint8_t>((sz >> 7) & 0xFF));
	} else {
	if (jpeg_size > kJpegSizeThreeByteMax) {
	LOG(FATAL) << "jpeg size is too big: " << jpeg_size << " must be under "
	<< kJpegSizeThreeByteMax;
	}
	const auto sz = static_cast<std::uint32_t>(jpeg_size);
	cuttlefish::AppendToMessage(frame_buffer_update,
	static_cast<std::uint8_t>((sz & 0x7F) \| 0x80),
	static_cast<std::uint8_t>(((sz >> 7) & 0x7F) \| 0x80),
	static_cast<std::uint8_t>((sz >> 14) & 0xFF));
	}
	}

	void VncClientConnection::AppendRawStripe(Message* frame_buffer_update,
	const Stripe& stripe) const {
	using Pixel = ScreenRegionView::Pixel;
	auto& fbu = *frame_buffer_update;
	AppendRawStripeHeader(&fbu, stripe);
	auto init_size = fbu.size();
	fbu.insert(fbu.end(), stripe.raw_data.begin(), stripe.raw_data.end());
	for (size_t i = init_size; i < fbu.size(); i += sizeof(Pixel)) {
	CHECK_LE(i + sizeof(Pixel), fbu.size());
	Pixel raw_pixel{};
	std::memcpy(&raw_pixel, &fbu[i], sizeof raw_pixel);
	auto red = RedVal(raw_pixel);
	auto green = GreenVal(raw_pixel);
	auto blue = BlueVal(raw_pixel);
	Pixel pixel = Pixel{red} << pixel_format_.red_shift \|
	Pixel{blue} << pixel_format_.blue_shift \|
	Pixel{green} << pixel_format_.green_shift;

	if (bool(pixel_format_.big_endian) != ImBigEndian()) {
	// flip them bits (refactor into function)
	auto p = reinterpret_cast<char*>(&pixel);
	std::swap(p[0], p[3]);
	std::swap(p[1], p[2]);
	}
	std::memcpy(&fbu[i], &pixel, sizeof pixel);
	}
	}

	Message VncClientConnection::MakeRawFrameBufferUpdate(
	const StripePtrVec& stripes) const {
	auto fbu =
	MakeFrameBufferUpdateHeader(static_cast<std::uint16_t>(stripes.size()));
	for (auto& stripe : stripes) {
	AppendRawStripe(&fbu, *stripe);
	}
	return fbu;
	}

	void VncClientConnection::AppendJpegStripeHeader(Message* frame_buffer_update,
	const Stripe& stripe) {
	static constexpr std::uint8_t kJpegEncoding = 0x90;
	cuttlefish::AppendToMessage(frame_buffer_update, stripe.x, stripe.y, stripe.width,
	stripe.height, kTightEncoding, kJpegEncoding);
	AppendJpegSize(frame_buffer_update, stripe.jpeg_data.size());
	}

	void VncClientConnection::AppendJpegStripe(Message* frame_buffer_update,
	const Stripe& stripe) {
	AppendJpegStripeHeader(frame_buffer_update, stripe);
	frame_buffer_update->insert(frame_buffer_update->end(),
	stripe.jpeg_data.begin(), stripe.jpeg_data.end());
	}

	Message VncClientConnection::MakeJpegFrameBufferUpdate(
	const StripePtrVec& stripes) {
	auto fbu =
	MakeFrameBufferUpdateHeader(static_cast<std::uint16_t>(stripes.size()));
	for (auto& stripe : stripes) {
	AppendJpegStripe(&fbu, *stripe);
	}
	return fbu;
	}

	Message VncClientConnection::MakeFrameBufferUpdate(
	const StripePtrVec& stripes) {
	return use_jpeg_compression_ ? MakeJpegFrameBufferUpdate(stripes)
	: MakeRawFrameBufferUpdate(stripes);
	}

	void VncClientConnection::FrameBufferUpdateRequestHandler(bool aggressive) {
	BlackBoard::Registerer reg(bb_, this);

	while (!closed()) {
	auto stripes = bb_->WaitForSenderWork(this);
	if (closed()) {
	break;
	}
	if (stripes.empty()) {
	LOG(FATAL) << "Got 0 stripes";
	}
	{
	// lock here so a portrait frame can't be sent after a landscape
	// DesktopSize update, or vice versa.
	std::lock_guard<std::mutex> guard(m_);
	DLOG(INFO) << "Sending update in "
	<< (current_orientation_ == ScreenOrientation::Portrait
	? "portrait"
	: "landscape")
	<< " mode";
	client_.SendNoSignal(MakeFrameBufferUpdate(stripes));
	}
	if (aggressive) {
	bb_->FrameBufferUpdateRequestReceived(this);
	}
	}
	}

	void VncClientConnection::SendDesktopSizeUpdate() {
	static constexpr int32_t kDesktopSizeEncoding = -223;
	client_.SendNoSignal(cuttlefish::CreateMessage(
	std::uint8_t{0}, // message-type,
	std::uint8_t{}, // padding
	std::uint16_t{1}, // one pseudo rectangle
	std::uint16_t{0}, std::uint16_t{0},
	static_cast<std::uint16_t>(ScreenWidth()),
	static_cast<std::uint16_t>(ScreenHeight()), kDesktopSizeEncoding));
	}

	bool VncClientConnection::IsUrgent(
	const FrameBufferUpdateRequest& update_request) const {
	return !update_request.incremental \|\|
	update_request != previous_update_request_;
	}

	void VncClientConnection::HandleFramebufferUpdateRequest() {
	auto msg = client_.Recv(kFramebufferUpdateRequestLength);
	if (msg.size() != kFramebufferUpdateRequestLength) {
	return;
	}
	FrameBufferUpdateRequest fbur{msg[1] == 0, uint16_tAt(&msg[1]),
	uint16_tAt(&msg[3]), uint16_tAt(&msg[5]),
	uint16_tAt(&msg[7])};
	if (IsUrgent(fbur)) {
	bb_->SignalClientNeedsEntireScreen(this);
	}
	bb_->FrameBufferUpdateRequestReceived(this);
	previous_update_request_ = fbur;
	}

	void VncClientConnection::HandleSetEncodings() {
	auto msg = client_.Recv(kSetEncodingsLength);
	if (msg.size() != kSetEncodingsLength) {
	return;
	}
	auto count = uint16_tAt(&msg[1]);
	auto encodings = client_.Recv(count * sizeof(int32_t));
	if (encodings.size() % sizeof(int32_t) != 0) {
	return;
	}
	{
	std::lock_guard<std::mutex> guard(m_);
	use_jpeg_compression_ = false;
	}
	for (size_t i = 0; i < encodings.size(); i += sizeof(int32_t)) {
	auto enc = int32_tAt(&encodings[i]);
	DLOG(INFO) << "client requesting encoding: " << enc;
	if (enc == kTightEncoding) {
	// This is a deviation from the spec which says that if a jpeg quality
	// level is not specified, tight encoding won't use jpeg.
	std::lock_guard<std::mutex> guard(m_);
	use_jpeg_compression_ = true;
	}
	if (kJpegMinQualityEncoding <= enc && enc <= kJpegMaxQualityEncoding) {
	DLOG(INFO) << "jpeg compression level: " << enc;
	bb_->set_jpeg_quality_level(enc);
	}
	if (enc == kDesktopSizeEncoding) {
	supports_desktop_size_encoding_ = true;
	}
	}
	}

	void VncClientConnection::HandleSetPixelFormat() {
	std::lock_guard<std::mutex> guard(m_);
	auto msg = client_.Recv(kSetPixelFormatLength);
	if (msg.size() != kSetPixelFormatLength) {
	return;
	}
	pixel_format_.bits_per_pixel = msg[3];
	pixel_format_.depth = msg[4];
	pixel_format_.big_endian = msg[5];
	pixel_format_.true_color = msg[7];
	pixel_format_.red_max = uint16_tAt(&msg[8]);
	pixel_format_.green_max = uint16_tAt(&msg[10]);
	pixel_format_.blue_max = uint16_tAt(&msg[12]);
	pixel_format_.red_shift = msg[13];
	pixel_format_.green_shift = msg[14];
	pixel_format_.blue_shift = msg[15];
	}

	void VncClientConnection::HandlePointerEvent() {
	auto msg = client_.Recv(kPointerEventLength);
	if (msg.size() != kPointerEventLength) {
	return;
	}
	std::uint8_t button_mask = msg[0];
	auto x_pos = uint16_tAt(&msg[1]);
	auto y_pos = uint16_tAt(&msg[3]);
	{
	std::lock_guard<std::mutex> guard(m_);
	if (current_orientation_ == ScreenOrientation::Landscape) {
	std::tie(x_pos, y_pos) =
	std::make_pair(ScreenConnectorInfo::ScreenWidth(0) - y_pos, x_pos);
	}
	}
	virtual_inputs_->HandlePointerEvent(button_mask, x_pos, y_pos);
	}

	void VncClientConnection::UpdateAccelerometer(float /x/, float /y/,
	float /z/) {
	// TODO(jemoreira): Implement when vsoc sensor hal is updated
	}

	VncClientConnection::Coordinates VncClientConnection::CoordinatesForOrientation(
	ScreenOrientation orientation) const {
	// Compute the acceleration vector that we need to send to mimic
	// this change.
	constexpr float g = 9.81;
	constexpr float angle = 20.0;
	const float cos_angle = std::cos(angle / M_PI);
	const float sin_angle = std::sin(angle / M_PI);
	const float z = g * sin_angle;
	switch (orientation) {
	case ScreenOrientation::Portrait:
	return {0, g * cos_angle, z};
	case ScreenOrientation::Landscape:
	return {g * cos_angle, 0, z};
	}
	}

	int VncClientConnection::ScreenWidth() const {
	return current_orientation_ == ScreenOrientation::Portrait
	? ScreenConnectorInfo::ScreenWidth(0)
	: ScreenConnectorInfo::ScreenHeight(0);
	}

	int VncClientConnection::ScreenHeight() const {
	return current_orientation_ == ScreenOrientation::Portrait
	? ScreenConnectorInfo::ScreenHeight(0)
	: ScreenConnectorInfo::ScreenWidth(0);
	}

	void VncClientConnection::SetScreenOrientation(ScreenOrientation orientation) {
	std::lock_guard<std::mutex> guard(m_);
	auto coords = CoordinatesForOrientation(orientation);
	UpdateAccelerometer(coords.x, coords.y, coords.z);
	if (supports_desktop_size_encoding_) {
	auto previous_orientation = current_orientation_;
	current_orientation_ = orientation;
	if (current_orientation_ != previous_orientation &&
	supports_desktop_size_encoding_) {
	SendDesktopSizeUpdate();
	bb_->SetOrientation(this, current_orientation_);
	// TODO not sure if I should be sending a frame update along with this,
	// or just letting the next FBUR handle it. This seems to me like it's
	// sending one more frame buffer update than was requested, which is
	// maybe a violation of the spec?
	}
	}
	}

	bool VncClientConnection::RotateIfIsRotationCommand(std::uint32_t key) {
	// Due to different configurations on different platforms we're supporting
	// a set of options for rotating the screen. These are similar to what
	// the emulator supports and has supported.
	// ctrl+left and ctrl+right work on windows and linux
	// command+left and command+right work on Mac
	// ctrl+fn+F11 and ctrl+fn+F12 work when chromoting to ubuntu from a Mac
	if (!control_key_down_ && !meta_key_down_) {
	return false;
	}
	switch (key) {
	case cuttlefish::xk::Right:
	case cuttlefish::xk::F12:
	DLOG(INFO) << "switching to portrait";
	SetScreenOrientation(ScreenOrientation::Portrait);
	break;
	case cuttlefish::xk::Left:
	case cuttlefish::xk::F11:
	DLOG(INFO) << "switching to landscape";
	SetScreenOrientation(ScreenOrientation::Landscape);
	break;
	default:
	return false;
	}
	return true;
	}

	void VncClientConnection::HandleKeyEvent() {
	auto msg = client_.Recv(kKeyEventLength);
	if (msg.size() != kKeyEventLength) {
	return;
	}

	auto key = uint32_tAt(&msg[3]);
	bool key_down = msg[0];
	switch (key) {
	case cuttlefish::xk::ControlLeft:
	case cuttlefish::xk::ControlRight:
	control_key_down_ = key_down;
	break;
	case cuttlefish::xk::MetaLeft:
	case cuttlefish::xk::MetaRight:
	meta_key_down_ = key_down;
	break;
	case cuttlefish::xk::F5:
	key = cuttlefish::xk::Menu;
	break;
	case cuttlefish::xk::F7:
	virtual_inputs_->PressPowerButton(key_down);
	return;
	default:
	break;
	}

	if (RotateIfIsRotationCommand(key)) {
	return;
	}

	virtual_inputs_->GenerateKeyPressEvent(key, key_down);
	}

	void VncClientConnection::HandleClientCutText() {
	auto msg = client_.Recv(kClientCutTextLength);
	if (msg.size() != kClientCutTextLength) {
	return;
	}
	auto len = uint32_tAt(&msg[3]);
	client_.Recv(len);
	}

	void VncClientConnection::NormalSession() {
	static constexpr std::uint8_t kSetPixelFormatMessage{0};
	static constexpr std::uint8_t kSetEncodingsMessage{2};
	static constexpr std::uint8_t kFramebufferUpdateRequestMessage{3};
	static constexpr std::uint8_t kKeyEventMessage{4};
	static constexpr std::uint8_t kPointerEventMessage{5};
	static constexpr std::uint8_t kClientCutTextMessage{6};
	while (true) {
	if (client_.closed()) {
	return;
	}
	auto msg = client_.Recv(1);
	if (client_.closed()) {
	return;
	}
	auto msg_type = msg.front();
	DLOG(INFO) << "Received message type " << msg_type;

	switch (msg_type) {
	case kSetPixelFormatMessage:
	HandleSetPixelFormat();
	break;

	case kSetEncodingsMessage:
	HandleSetEncodings();
	break;

	case kFramebufferUpdateRequestMessage:
	HandleFramebufferUpdateRequest();
	break;

	case kKeyEventMessage:
	HandleKeyEvent();
	break;

	case kPointerEventMessage:
	HandlePointerEvent();
	break;

	case kClientCutTextMessage:
	HandleClientCutText();
	break;

	default:
	LOG(WARNING) << "message type not handled: "
	<< static_cast<int>(msg_type);
	break;
	}
	}
	}