Make it work over tcpip

"adb reverse" currently does not work over tcpip (i.e. on a device
connected by "adb connect"):
<https://issuetracker.google.com/issues/37066218>

To work around the problem, if the call to "adb reverse" fails, then
fallback to "adb forward", and reverse the client/server roles.

Keep the "adb reverse" mode as the default because it does not involve
connection retries: when using "adb forward", the client must try to
connect successively until the server listens.

Due to the tunnel, every connect() will succeed, so the client must
attempt to read() to detect a connection failure. For this purpose, when
using the "adb forward" mode, the server initially writes a dummy byte,
read by the client.

Fixes <https://github.com/Genymobile/scrcpy/issues/5>.

FAQ.md

@@ -1,84 +0,0 @@
-# Frequently Asked Questions
-
-## Common issues
-
-The application is very young, it is not unlikely that you encounter problems
-with it.
-
-Here are the common reported problems and their status.
-
-### On Windows, I have no output in the console
-
-When run in `cmd.exe`, the application does not print anything. Even `scrcpy
---help` have no output. We don't know why yet.
-
-However, if you run the very same `scrcpy.exe` from
-[MSYS2](https://www.msys2.org/) (`mingw64`), then it correctly prints output.
-
-
-### On Windows, when I start the application, nothing happens
-
-The previous problem does not help to get a clue about the cause.
-
-The most common is your device not being detected by `adb`, or is unauthorized.
-Check everything is ok by calling:
-
-    adb devices
-
-Windows may need some [drivers] to detect your device.
-
-[drivers]: https://developer.android.com/studio/run/oem-usb.html
-
-If you still encounter problems, please see [issue 9].
-
-[issue 9]: https://github.com/Genymobile/scrcpy/issues/9
-
-
-### The application does not work over `adb connect`
-
-If the device is connected using `adb connect`, then you'll get this error:
-
-    error: more than one device/emulator
-    ERROR: "adb reverse" returned with value 1
-
-We plan to support it in future versions. See [issue 5].
-
-[issue 5]: https://github.com/Genymobile/scrcpy/issues/5
-
-
-### Mouse clicks do not work
-
-On many LG devices, [mouse clicks do not work][issue 18]. We're [working][pr27]
-on it.
-
-[issue 18]: https://github.com/Genymobile/scrcpy/issues/18
-[pr27]: https://github.com/Genymobile/scrcpy/pull/27
-
-
-### I get a black screen for some applications like Silence
-
-This is expected, they requested to protect the screen.
-
-In [Silence], you can disable it in settings → Privacy → Screen security.
-
-[silence]: https://f-droid.org/en/packages/org.smssecure.smssecure/
-
-See [issue 36].
-
-[issue 36]: https://github.com/Genymobile/scrcpy/issues/36
-
-
-### Mouse clicks at wrong location
-
-On MacOS, with HiDPI support and multiple screens, input location are wrongly
-scaled. See [issue 15].
-
-[issue 15]: https://github.com/Genymobile/scrcpy/issues/15
-
-A workaround is to build with HiDPI support disabled:
-
-```bash
-meson x --buildtype release -Dhidpi_support=false
-```
-
-However, the video will be displayed at lower resolution.

README.md

@@ -2,7 +2,7 @@
 
 This application provides display and control of Android devices connected on
 USB. It does not require any _root_ access. It works on _GNU/Linux_, _Windows_
-and _MacOS_.
+and _Mac OS_.
 
 ![screenshot](assets/screenshot-debian-600.jpg)
 
@@ -37,44 +37,15 @@ The client requires _FFmpeg_ and _LibSDL2_.
 
 #### Linux
 
-Install the required packages from your package manager.
+Install the required packages from your package manager (here, for Debian):
 
-##### Debian/Ubuntu
+    # runtime dependencies
+    sudo apt install ffmpeg libsdl2-2.0.0
 
-```bash
-# runtime dependencies
-sudo apt install ffmpeg libsdl2-2.0.0
-
-# client build dependencies
-sudo apt install make gcc pkg-config meson \
-                 libavcodec-dev libavformat-dev libavutil-dev \
-                 libsdl2-dev
-
-# server build dependencies
-sudo apt install openjdk-8-jdk
-```
-
-##### Fedora
-
-```bash
-# enable RPM fusion free
-sudo dnf install https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm
-
-# client build dependencies
-sudo dnf install SDL2-devel ffms2-devel meson gcc make
-
-# server build dependencies
-sudo dnf install java
-```
-
-##### Arch Linux
-
-Two [AUR] packages have been created by users:
-
- - [`scrcpy`](https://aur.archlinux.org/packages/scrcpy/)
- - [`scrcpy-prebuiltserver`](https://aur.archlinux.org/packages/scrcpy-prebuiltserver/)
-
-[AUR]: https://wiki.archlinux.org/index.php/Arch_User_Repository
+    # build dependencies
+    sudo apt install make gcc openjdk-8-jdk pkg-config meson zip \
+                     libavcodec-dev libavformat-dev libavutil-dev \
+                     libsdl2-dev
 
 
 #### Windows
@@ -94,24 +65,22 @@ project. From an MSYS2 terminal, install the required packages:
 
 [MSYS2]: http://www.msys2.org/
 
-```bash
-# runtime dependencies
-pacman -S mingw-w64-x86_64-SDL2 \
-          mingw-w64-x86_64-ffmpeg
+    # runtime dependencies
+    pacman -S mingw-w64-x86_64-SDL2 \
+              mingw-w64-x86_64-ffmpeg
 
-# client build dependencies
-pacman -S mingw-w64-x86_64-make \
-          mingw-w64-x86_64-gcc \
-          mingw-w64-x86_64-pkg-config \
-          mingw-w64-x86_64-meson
-```
+    # build dependencies
+    pacman -S mingw-w64-x86_64-make \
+              mingw-w64-x86_64-gcc \
+              mingw-w64-x86_64-pkg-config \
+              mingw-w64-x86_64-meson \
+              zip
 
 Java (>= 7) is not available in MSYS2, so if you plan to build the server,
 install it manually and make it available from the `PATH`:
 
-```bash
-export PATH="$JAVA_HOME/bin:$PATH"
-```
+    export PATH="$JAVA_HOME/bin:$PATH"
+
 
 #### Mac OS
 
@@ -119,20 +88,17 @@ Use [Homebrew] to install the packages:
 
 [Homebrew]: https://brew.sh/
 
-```bash
-# runtime dependencies
-brew install sdl2 ffmpeg
+    # runtime dependencies
+    brew install sdl2 ffmpeg
 
-# client build dependencies
-brew install gcc pkg-config meson
-```
+    # build dependencies
+    brew install gcc pkg-config meson zip
 
 Java (>= 7) is not available in Homebrew, so if you plan to build the server,
 install it manually and make it available from the `PATH`:
 
-```bash
-export PATH="$JAVA_HOME/bin:$PATH"
-```
+    export PATH="$JAVA_HOME/bin:$PATH"
+
 
 ### Common steps
 
@@ -141,29 +107,21 @@ its directory. For example:
 
 [Android SDK]: https://developer.android.com/studio/index.html
 
-```bash
-export ANDROID_HOME=~/android/sdk
-```
+    export ANDROID_HOME=~/android/sdk
 
 Then, build `scrcpy`:
 
-```bash
-meson x --buildtype release --strip -Db_lto=true
-cd x
-ninja
-```
+    meson x --buildtype release --strip -Db_lto=true
+    cd x
+    ninja
 
 You can test it from here:
 
-```bash
-ninja run
-```
+    ninja run
 
 Or you can install it on the system:
 
-```bash
-sudo ninja install    # without sudo on Windows
-```
+    sudo ninja install    # without sudo on Windows
 
 This installs two files:
 
@@ -189,13 +147,12 @@ In that case, the build does not require Java or the Android SDK.
 Download the prebuilt server somewhere, and specify its path during the Meson
 configuration:
 
-```bash
-meson x --buildtype release --strip -Db_lto=true \
-    -Dprebuilt_server=/path/to/scrcpy-server.jar
-cd x
-ninja
-sudo ninja install
-```
+    meson x --buildtype release --strip -Db_lto=true \
+        -Dprebuilt_server=/path/to/scrcpy-server.jar
+    cd x
+    ninja
+    sudo ninja install
+
 
 ## Run
 
@@ -203,60 +160,50 @@ _At runtime, `adb` must be accessible from your `PATH`._
 
 If everything is ok, just plug an Android device, and execute:
 
-```bash
-scrcpy
-```
+    scrcpy
 
 It accepts command-line arguments, listed by:
 
-```bash
-scrcpy --help
-```
+    scrcpy --help
 
 For example, to decrease video bitrate to 2Mbps (default is 8Mbps):
 
-```bash
-scrcpy -b 2M
-```
+    scrcpy -b 2M
 
 To limit the video dimensions (e.g. if the device is 2540×1440, but the host
 screen is smaller, or cannot decode such a high definition):
 
-```bash
-scrcpy -m 1024
-```
+    scrcpy -m 1024
 
 If several devices are listed in `adb devices`, you must specify the _serial_:
 
-```bash
-scrcpy -s 0123456789abcdef
-```
+    scrcpy -s 0123456789abcdef
 
 To run without installing:
 
-```bash
-./run x [options]
-```
+    ./run x [options]
 
 (where `x` is your build directory).
 
 
 ## Shortcuts
 
- | Action                                 |   Shortcut    |
- | -------------------------------------  | -------------:|
- | switch fullscreen mode                 | `Ctrl`+`f`    |
- | resize window to 1:1 (pixel-perfect)   | `Ctrl`+`g`    |
- | resize window to remove black borders  | `Ctrl`+`x`    |
- | click on `HOME`                        | `Ctrl`+`h`    |
- | click on `BACK`                        | `Ctrl`+`b`    |
- | click on `APP_SWITCH`                  | `Ctrl`+`m`    |
- | click on `VOLUME_UP`                   | `Ctrl`+`+`    |
- | click on `VOLUME_DOWN`                 | `Ctrl`+`-`    |
- | click on `POWER`                       | `Ctrl`+`p`    |
- | turn screen on                         | _Right-click_ |
- | paste computer clipboard to device     | `Ctrl`+`v`    |
- | enable/disable FPS counter (on stdout) | `Ctrl`+`i`    |
+ | Action                                 |   Shortcut                   |
+ | -------------------------------------- |:---------------------------- |
+ | switch fullscreen mode                 | `Ctrl`+`f`                   |
+ | resize window to 1:1 (pixel-perfect)   | `Ctrl`+`g`                   |
+ | resize window to remove black borders  | `Ctrl`+`x`                   |
+ | click on `HOME`                        | `Ctrl`+`h` \| _Middle-click_ |
+ | click on `BACK`                        | `Ctrl`+`b` \| _Right-click¹_ |
+ | click on `APP_SWITCH`                  | `Ctrl`+`m`                   |
+ | click on `VOLUME_UP`                   | `Ctrl`+`+`                   |
+ | click on `VOLUME_DOWN`                 | `Ctrl`+`-`                   |
+ | click on `POWER`                       | `Ctrl`+`p`                   |
+ | turn screen on                         | _Right-click¹_               |
+ | paste computer clipboard to device     | `Ctrl`+`v`                   |
+ | enable/disable FPS counter (on stdout) | `Ctrl`+`i`                   |
+
+_¹Right-click turns the screen on if it was off, presses BACK otherwise._
 
 
 ## Why _scrcpy_?
@@ -269,11 +216,6 @@ A colleague challenged me to find a name as unpronounceable as [gnirehtet].
 [`strcpy`]: http://man7.org/linux/man-pages/man3/strcpy.3.html
 
 
-## Common issues
-
-See the [FAQ](FAQ.md).
-
-
 ## Developers
 
 Read the [developers page].

app/src/command.c

@@ -45,6 +45,13 @@ process_t adb_forward(const char *serial, uint16_t local_port, const char *devic
     return adb_execute(serial, adb_cmd, ARRAY_LEN(adb_cmd));
 }
 
+process_t adb_forward_remove(const char *serial, uint16_t local_port) {
+    char local[4 + 5 + 1]; // tcp:PORT
+    sprintf(local, "tcp:%" PRIu16, local_port);
+    const char *const adb_cmd[] = {"forward", "--remove", local};
+    return adb_execute(serial, adb_cmd, ARRAY_LEN(adb_cmd));
+}
+
 process_t adb_reverse(const char *serial, const char *device_socket_name, uint16_t local_port) {
     char local[4 + 5 + 1]; // tcp:PORT
     char remote[108 + 14 + 1]; // localabstract:NAME

app/src/command.h

@@ -39,6 +39,7 @@ SDL_bool cmd_simple_wait(process_t pid, exit_code_t *exit_code);
 
 process_t adb_execute(const char *serial, const char *const adb_cmd[], int len);
 process_t adb_forward(const char *serial, uint16_t local_port, const char *device_socket_name);
+process_t adb_forward_remove(const char *serial, uint16_t local_port);
 process_t adb_reverse(const char *serial, const char *device_socket_name, uint16_t local_port);
 process_t adb_reverse_remove(const char *serial, const char *device_socket_name);
 process_t adb_push(const char *serial, const char *local, const char *remote);

app/src/controlevent.c

@@ -39,9 +39,9 @@ int control_event_serialize(const struct control_event *event, unsigned char *bu
                 // injecting a text takes time, so limit the text length
                 len = TEXT_MAX_LENGTH;
             }
-            buf[1] = (Uint8) len;
-            memcpy(&buf[2], event->text_event.text, len);
-            return 2 + len;
+            write16(&buf[1], (Uint16) len);
+            memcpy(&buf[3], event->text_event.text, len);
+            return 3 + len;
         }
         case CONTROL_EVENT_TYPE_MOUSE:
             buf[1] = event->mouse_event.action;

app/src/controlevent.h

@@ -9,8 +9,8 @@
 #include "common.h"
 
 #define CONTROL_EVENT_QUEUE_SIZE 64
-#define SERIALIZED_EVENT_MAX_SIZE 33
-#define TEXT_MAX_LENGTH 256
+#define TEXT_MAX_LENGTH 300
+#define SERIALIZED_EVENT_MAX_SIZE 3 + TEXT_MAX_LENGTH
 
 enum control_event_type {
     CONTROL_EVENT_TYPE_KEYCODE,
@@ -20,7 +20,7 @@ enum control_event_type {
     CONTROL_EVENT_TYPE_COMMAND,
 };
 
-#define CONTROL_EVENT_COMMAND_SCREEN_ON 0
+#define CONTROL_EVENT_COMMAND_BACK_OR_SCREEN_ON 0
 
 struct control_event {
     enum control_event_type type;

app/src/convert.c

@@ -172,10 +172,7 @@ SDL_bool mouse_wheel_from_sdl_to_android(const SDL_MouseWheelEvent *from,
     to->scroll_event.position = position;
 
     int mul = from->direction == SDL_MOUSEWHEEL_NORMAL ? 1 : -1;
-    // SDL behavior seems inconsistent between horizontal and vertical scrolling
-    // so reverse the horizontal
-    // <https://wiki.libsdl.org/SDL_MouseWheelEvent#Remarks>
-    to->scroll_event.hscroll = -mul * from->x;
+    to->scroll_event.hscroll = mul * from->x;
     to->scroll_event.vscroll = mul * from->y;
 
     return SDL_TRUE;

app/src/inputmanager.c

@@ -78,10 +78,11 @@ static inline void action_volume_down(struct controller *controller) {
     send_keycode(controller, AKEYCODE_VOLUME_DOWN, "VOLUME_DOWN");
 }
 
-static void turn_screen_on(struct controller *controller) {
+// turn the screen on if it was off, press BACK otherwise
+static void press_back_or_turn_screen_on(struct controller *controller) {
     struct control_event control_event;
     control_event.type = CONTROL_EVENT_TYPE_COMMAND;
-    control_event.command_event.action = CONTROL_EVENT_COMMAND_SCREEN_ON;
+    control_event.command_event.action = CONTROL_EVENT_COMMAND_BACK_OR_SCREEN_ON;
 
     if (!controller_push_event(controller, &control_event)) {
         LOGW("Cannot turn screen on");
@@ -225,9 +226,15 @@ void input_manager_process_mouse_motion(struct input_manager *input_manager,
 
 void input_manager_process_mouse_button(struct input_manager *input_manager,
                                         const SDL_MouseButtonEvent *event) {
-    if (event->button == SDL_BUTTON_RIGHT && event->type == SDL_MOUSEBUTTONDOWN) {
-        turn_screen_on(input_manager->controller);
-        return;
+    if (event->type == SDL_MOUSEBUTTONDOWN) {
+        if (event->button == SDL_BUTTON_RIGHT) {
+            press_back_or_turn_screen_on(input_manager->controller);
+            return;
+        }
+        if (event->button == SDL_BUTTON_MIDDLE) {
+            action_home(input_manager->controller);
+            return;
+        }
     };
     struct control_event control_event;
     if (mouse_button_from_sdl_to_android(event, input_manager->screen->frame_size, &control_event)) {

app/src/main.c

@@ -61,10 +61,12 @@ static void usage(const char *arg0) {
         "\n"
         "    Ctrl+h\n"
         "    Home\n"
+        "    Middle-click\n"
         "        click on HOME\n"
         "\n"
         "    Ctrl+b\n"
         "    Ctrl+Backspace\n"
+        "    Right-click (when screen is on)\n"
         "        click on BACK\n"
         "\n"
         "    Ctrl+m\n"
@@ -79,7 +81,7 @@ static void usage(const char *arg0) {
         "    Ctrl+p\n"
         "        click on POWER (turn screen on/off)\n"
         "\n"
-        "    Right-click\n"
+        "    Right-click (when screen is off)\n"
         "        turn screen on\n"
         "\n"
         "    Ctrl+v\n"

app/src/net.c

@@ -18,6 +18,26 @@
   typedef struct in_addr IN_ADDR;
 #endif
 
+socket_t net_connect(Uint32 addr, Uint16 port) {
+    socket_t sock = socket(AF_INET, SOCK_STREAM, 0);
+    if (sock == INVALID_SOCKET) {
+        perror("socket");
+        return INVALID_SOCKET;
+    }
+
+    SOCKADDR_IN sin;
+    sin.sin_family = AF_INET;
+    sin.sin_addr.s_addr = htonl(addr);
+    sin.sin_port = htons(port);
+
+    if (connect(sock, (SOCKADDR *) &sin, sizeof(sin)) == SOCKET_ERROR) {
+        perror("connect");
+        return INVALID_SOCKET;
+    }
+
+    return sock;
+}
+
 socket_t net_listen(Uint32 addr, Uint16 port, int backlog) {
     socket_t sock = socket(AF_INET, SOCK_STREAM, 0);
     if (sock == INVALID_SOCKET) {

app/src/net.h

@@ -21,6 +21,7 @@
 SDL_bool net_init(void);
 void net_cleanup(void);
 
+socket_t net_connect(Uint32 addr, Uint16 port);
 socket_t net_listen(Uint32 addr, Uint16 port, int backlog);
 socket_t net_accept(socket_t server_socket);
 

app/src/scrcpy.c

@@ -103,9 +103,9 @@ SDL_bool scrcpy(const char *serial, Uint16 local_port, Uint16 max_size, Uint32 b
     // managed by the event loop. This blocking call blocks the event loop, so
     // timeout the connection not to block indefinitely in case of SIGTERM.
 #define SERVER_CONNECT_TIMEOUT_MS 2000
-    socket_t device_socket = server_connect_to(&server, serial, SERVER_CONNECT_TIMEOUT_MS);
+    socket_t device_socket = server_connect_to(&server, SERVER_CONNECT_TIMEOUT_MS);
     if (device_socket == INVALID_SOCKET) {
-        server_stop(&server, serial);
+        server_stop(&server);
         ret = SDL_FALSE;
         goto finally_destroy_server;
     }
@@ -117,13 +117,13 @@ SDL_bool scrcpy(const char *serial, Uint16 local_port, Uint16 max_size, Uint32 b
     // therefore, we transmit the screen size before the video stream, to be able
     // to init the window immediately
     if (!device_read_info(device_socket, device_name, &frame_size)) {
-        server_stop(&server, serial);
+        server_stop(&server);
         ret = SDL_FALSE;
         goto finally_destroy_server;
     }
 
     if (!frames_init(&frames)) {
-        server_stop(&server, serial);
+        server_stop(&server);
         ret = SDL_FALSE;
         goto finally_destroy_server;
     }
@@ -134,7 +134,7 @@ SDL_bool scrcpy(const char *serial, Uint16 local_port, Uint16 max_size, Uint32 b
     // start the decoder
     if (!decoder_start(&decoder)) {
         ret = SDL_FALSE;
-        server_stop(&server, serial);
+        server_stop(&server);
         goto finally_destroy_frames;
     }
 
@@ -165,7 +165,7 @@ finally_destroy_controller:
 finally_stop_decoder:
     decoder_stop(&decoder);
     // stop the server before decoder_join() to wake up the decoder
-    server_stop(&server, serial);
+    server_stop(&server);
     decoder_join(&decoder);
 finally_destroy_frames:
     frames_destroy(&frames);

app/src/screen.c

@@ -18,8 +18,8 @@ SDL_bool sdl_init_and_configure(void) {
 
     atexit(SDL_Quit);
 
-    // Bilinear resizing
-    if (!SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "1")) {
+    // Use the best available scale quality
+    if (!SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "2")) {
         LOGW("Could not enable bilinear filtering");
     }
 

app/src/server.c

@@ -4,6 +4,7 @@
 #include <inttypes.h>
 #include <stdint.h>
 #include <SDL2/SDL_assert.h>
+#include <SDL2/SDL_timer.h>
 
 #include "config.h"
 #include "log.h"
@@ -37,17 +38,45 @@ static SDL_bool remove_server(const char *serial) {
     return process_check_success(process, "adb shell rm");
 }
 
-static SDL_bool enable_tunnel(const char *serial, Uint16 local_port) {
+static SDL_bool enable_tunnel_reverse(const char *serial, Uint16 local_port) {
     process_t process = adb_reverse(serial, SOCKET_NAME, local_port);
     return process_check_success(process, "adb reverse");
 }
 
-static SDL_bool disable_tunnel(const char *serial) {
+static SDL_bool disable_tunnel_reverse(const char *serial) {
     process_t process = adb_reverse_remove(serial, SOCKET_NAME);
     return process_check_success(process, "adb reverse --remove");
 }
 
-static process_t execute_server(const char *serial, Uint16 max_size, Uint32 bit_rate) {
+static SDL_bool enable_tunnel_forward(const char *serial, Uint16 local_port) {
+    process_t process = adb_forward(serial, local_port, SOCKET_NAME);
+    return process_check_success(process, "adb forward");
+}
+
+static SDL_bool disable_tunnel_forward(const char *serial, Uint16 local_port) {
+    process_t process = adb_forward_remove(serial, local_port);
+    return process_check_success(process, "adb forward --remove");
+}
+
+static SDL_bool enable_tunnel(struct server *server) {
+    if (enable_tunnel_reverse(server->serial, server->local_port)) {
+        return SDL_TRUE;
+    }
+
+    LOGW("'adb reverse' failed, fallback to 'adb forward'");
+    server->tunnel_forward = SDL_TRUE;
+    return enable_tunnel_forward(server->serial, server->local_port);
+}
+
+static SDL_bool disable_tunnel(struct server *server) {
+    if (server->tunnel_forward) {
+        return disable_tunnel_forward(server->serial, server->local_port);
+    }
+    return disable_tunnel_reverse(server->serial);
+}
+
+static process_t execute_server(const char *serial,
+                                Uint16 max_size, Uint32 bit_rate, SDL_bool tunnel_forward) {
     char max_size_string[6];
     char bit_rate_string[11];
     sprintf(max_size_string, "%"PRIu16, max_size);
@@ -60,15 +89,48 @@ static process_t execute_server(const char *serial, Uint16 max_size, Uint32 bit_
         "com.genymobile.scrcpy.Server",
         max_size_string,
         bit_rate_string,
+        tunnel_forward ? "true" : "false",
     };
     return adb_execute(serial, cmd, sizeof(cmd) / sizeof(cmd[0]));
 }
 
-static socket_t listen_on_port(Uint16 port) {
 #define IPV4_LOCALHOST 0x7F000001
+
+static socket_t listen_on_port(Uint16 port) {
     return net_listen(IPV4_LOCALHOST, port, 1);
 }
 
+static socket_t connect_and_read_byte(Uint16 port) {
+    socket_t socket = net_connect(IPV4_LOCALHOST, port);
+    if (socket == INVALID_SOCKET) {
+        return INVALID_SOCKET;
+    }
+
+    char byte;
+    // the connection may succeed even if the server behind the "adb tunnel"
+    // is not listening, so read one byte to detect a working connection
+    if (net_recv_all(socket, &byte, 1) != 1) {
+        // the server is not listening yet behind the adb tunnel
+        return INVALID_SOCKET;
+    }
+    return socket;
+}
+
+static socket_t connect_to_server(Uint16 port, Uint32 attempts, Uint32 delay) {
+    do {
+        LOGD("Remaining connection attempts: %d", (int) attempts);
+        socket_t socket = connect_and_read_byte(port);
+        if (socket != INVALID_SOCKET) {
+            // it worked!
+            return socket;
+        }
+        if (attempts) {
+            SDL_Delay(delay);
+        }
+    } while (--attempts > 0);
+    return INVALID_SOCKET;
+}
+
 static void close_socket(socket_t *socket) {
     SDL_assert(*socket != INVALID_SOCKET);
     net_shutdown(*socket, SHUT_RDWR);
@@ -85,63 +147,84 @@ void server_init(struct server *server) {
 
 SDL_bool server_start(struct server *server, const char *serial, Uint16 local_port,
                       Uint16 max_size, Uint32 bit_rate) {
+    server->local_port = local_port;
+
+    if (serial) {
+        server->serial = SDL_strdup(serial);
+    }
+
     if (!push_server(serial)) {
         return SDL_FALSE;
     }
 
     server->server_copied_to_device = SDL_TRUE;
 
-    if (!enable_tunnel(serial, local_port)) {
+    if (!enable_tunnel(server)) {
         return SDL_FALSE;
     }
 
-    // At the application level, the device part is "the server" because it
-    // serves video stream and control. However, at the network level, the
-    // client listens and the server connects to the client. That way, the
-    // client can listen before starting the server app, so there is no need to
-    // try to connect until the server socket is listening on the device.
+    // if "adb reverse" does not work (e.g. over "adb connect"), it fallbacks to
+    // "adb forward", so the app socket is the client
+    if (!server->tunnel_forward) {
+        // At the application level, the device part is "the server" because it
+        // serves video stream and control. However, at the network level, the
+        // client listens and the server connects to the client. That way, the
+        // client can listen before starting the server app, so there is no need to
+        // try to connect until the server socket is listening on the device.
 
-    server->server_socket = listen_on_port(local_port);
-    if (server->server_socket == INVALID_SOCKET) {
-        LOGE("Could not listen on port %" PRIu16, local_port);
-        disable_tunnel(serial);
-        return SDL_FALSE;
+        server->server_socket = listen_on_port(local_port);
+        if (server->server_socket == INVALID_SOCKET) {
+            LOGE("Could not listen on port %" PRIu16, local_port);
+            disable_tunnel(server);
+            return SDL_FALSE;
+        }
     }
 
     // server will connect to our server socket
-    server->process = execute_server(serial, max_size, bit_rate);
+    server->process = execute_server(serial, max_size, bit_rate, server->tunnel_forward);
     if (server->process == PROCESS_NONE) {
-        close_socket(&server->server_socket);
-        disable_tunnel(serial);
+        if (!server->tunnel_forward) {
+            close_socket(&server->server_socket);
+        }
+        disable_tunnel(server);
         return SDL_FALSE;
     }
 
-    server->adb_reverse_enabled = SDL_TRUE;
+    server->tunnel_enabled = SDL_TRUE;
 
     return SDL_TRUE;
 }
 
-socket_t server_connect_to(struct server *server, const char *serial, Uint32 timeout_ms) {
-    server->device_socket = net_accept(server->server_socket);
+socket_t server_connect_to(struct server *server, Uint32 timeout_ms) {
+    if (!server->tunnel_forward) {
+        server->device_socket = net_accept(server->server_socket);
+    } else {
+        Uint32 attempts = 10;
+        Uint32 delay = 100; // ms
+        server->device_socket = connect_to_server(server->local_port, attempts, delay);
+    }
+
     if (server->device_socket == INVALID_SOCKET) {
         return INVALID_SOCKET;
     }
 
-    // we don't need the server socket anymore
-    close_socket(&server->server_socket);
+    if (!server->tunnel_forward) {
+        // we don't need the server socket anymore
+        close_socket(&server->server_socket);
+    }
 
     // the server is started, we can clean up the jar from the temporary folder
-    remove_server(serial); // ignore failure
+    remove_server(server->serial); // ignore failure
     server->server_copied_to_device = SDL_FALSE;
 
     // we don't need the adb tunnel anymore
-    disable_tunnel(serial); // ignore failure
-    server->adb_reverse_enabled = SDL_FALSE;
+    disable_tunnel(server); // ignore failure
+    server->tunnel_enabled = SDL_FALSE;
 
     return server->device_socket;
 }
 
-void server_stop(struct server *server, const char *serial) {
+void server_stop(struct server *server) {
     SDL_assert(server->process != PROCESS_NONE);
 
     if (!cmd_terminate(server->process)) {
@@ -151,13 +234,13 @@ void server_stop(struct server *server, const char *serial) {
     cmd_simple_wait(server->process, NULL); // ignore exit code
     LOGD("Server terminated");
 
-    if (server->adb_reverse_enabled) {
+    if (server->tunnel_enabled) {
         // ignore failure
-        disable_tunnel(serial);
+        disable_tunnel(server);
     }
 
     if (server->server_copied_to_device) {
-        remove_server(serial); // ignore failure
+        remove_server(server->serial); // ignore failure
     }
 }
 
@@ -168,4 +251,5 @@ void server_destroy(struct server *server) {
     if (server->device_socket != INVALID_SOCKET) {
         close_socket(&server->device_socket);
     }
+    SDL_free((void *) server->serial);
 }

app/src/server.h

@@ -5,18 +5,24 @@
 #include "net.h"
 
 struct server {
+    const char *serial;
     process_t process;
-    socket_t server_socket;
+    socket_t server_socket; // only used if !tunnel_forward
     socket_t device_socket;
-    SDL_bool adb_reverse_enabled;
+    Uint16 local_port;
+    SDL_bool tunnel_enabled;
+    SDL_bool tunnel_forward; // use "adb forward" instead of "adb reverse"
     SDL_bool server_copied_to_device;
 };
 
 #define SERVER_INITIALIZER {              \
+    .serial = NULL,                       \
     .process = PROCESS_NONE,              \
     .server_socket = INVALID_SOCKET,      \
     .device_socket = INVALID_SOCKET,      \
-    .adb_reverse_enabled = SDL_FALSE,     \
+    .local_port = 0,                      \
+    .tunnel_enabled = SDL_FALSE,          \
+    .tunnel_forward = SDL_FALSE,          \
     .server_copied_to_device = SDL_FALSE, \
 }
 
@@ -28,10 +34,10 @@ SDL_bool server_start(struct server *server, const char *serial, Uint16 local_po
                       Uint16 max_size, Uint32 bit_rate);
 
 // block until the communication with the server is established
-socket_t server_connect_to(struct server *server, const char *serial, Uint32 timeout_ms);
+socket_t server_connect_to(struct server *server, Uint32 timeout_ms);
 
 // disconnect and kill the server process
-void server_stop(struct server *server, const char *serial);
+void server_stop(struct server *server);
 
 // close and release sockets
 void server_destroy(struct server *server);

app/tests/test_control_event_serialize.c

@@ -35,16 +35,36 @@ static void test_serialize_text_event() {
 
     unsigned char buf[SERIALIZED_EVENT_MAX_SIZE];
     int size = control_event_serialize(&event, buf);
-    assert(size == 15);
+    assert(size == 16);
 
     const unsigned char expected[] = {
         0x01, // CONTROL_EVENT_TYPE_KEYCODE
-        0x0d, // text length
+        0x00, 0x0d, // text length
         'h', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // text
     };
     assert(!memcmp(buf, expected, sizeof(expected)));
 }
 
+static void test_serialize_long_text_event() {
+    struct control_event event;
+    event.type = CONTROL_EVENT_TYPE_TEXT;
+    char text[TEXT_MAX_LENGTH];
+    memset(text, 'a', sizeof(text));
+    event.text_event.text = text;
+
+    unsigned char buf[SERIALIZED_EVENT_MAX_SIZE];
+    int size = control_event_serialize(&event, buf);
+    assert(size == 3 + sizeof(text));
+
+    unsigned char expected[3 + TEXT_MAX_LENGTH];
+    expected[0] = 0x01; // CONTROL_EVENT_TYPE_KEYCODE
+    expected[1] = 0x01;
+    expected[2] = 0x2c; // text length (16 bits)
+    memset(&expected[3], 'a', TEXT_MAX_LENGTH);
+
+    assert(!memcmp(buf, expected, sizeof(expected)));
+}
+
 static void test_serialize_mouse_event() {
     struct control_event event = {
         .type = CONTROL_EVENT_TYPE_MOUSE,
@@ -114,6 +134,7 @@ static void test_serialize_scroll_event() {
 int main() {
     test_serialize_keycode_event();
     test_serialize_text_event();
+    test_serialize_long_text_event();
     test_serialize_mouse_event();
     test_serialize_scroll_event();
     return 0;

server/src/main/java/com/genymobile/scrcpy/ControlEvent.java

@@ -11,7 +11,7 @@ public final class ControlEvent {
     public static final int TYPE_SCROLL = 3;
     public static final int TYPE_COMMAND = 4;
 
-    public static final int COMMAND_SCREEN_ON = 0;
+    public static final int COMMAND_BACK_OR_SCREEN_ON = 0;
 
     private int type;
     private String text;

server/src/main/java/com/genymobile/scrcpy/ControlEventReader.java

@@ -13,8 +13,8 @@ public class ControlEventReader {
     private static final int SCROLL_PAYLOAD_LENGTH = 16;
     private static final int COMMAND_PAYLOAD_LENGTH = 1;
 
-    private static final int TEXT_MAX_LENGTH = 256;
-    private static final int RAW_BUFFER_SIZE = 128;
+    public static final int TEXT_MAX_LENGTH = 300;
+    private static final int RAW_BUFFER_SIZE = 1024;
 
     private final byte[] rawBuffer = new byte[RAW_BUFFER_SIZE];
     private final ByteBuffer buffer = ByteBuffer.wrap(rawBuffer);
@@ -94,7 +94,7 @@ public class ControlEventReader {
         if (buffer.remaining() < 1) {
             return null;
         }
-        int len = toUnsigned(buffer.get());
+        int len = toUnsigned(buffer.getShort());
         if (buffer.remaining() < len) {
             return null;
         }

server/src/main/java/com/genymobile/scrcpy/DesktopConnection.java

@@ -1,5 +1,6 @@
 package com.genymobile.scrcpy;
 
+import android.net.LocalServerSocket;
 import android.net.LocalSocket;
 import android.net.LocalSocketAddress;
 
@@ -33,8 +34,20 @@ public final class DesktopConnection implements Closeable {
         return localSocket;
     }
 
-    public static DesktopConnection open(Device device) throws IOException {
-        LocalSocket socket = connect(SOCKET_NAME);
+    private static LocalSocket listenAndAccept(String abstractName) throws IOException {
+        LocalServerSocket localServerSocket = new LocalServerSocket(abstractName);
+        return localServerSocket.accept();
+    }
+
+    public static DesktopConnection open(Device device, boolean tunnelForward) throws IOException {
+        LocalSocket socket;
+        if (tunnelForward) {
+            socket = listenAndAccept(SOCKET_NAME);
+            // send one byte so the client may read() to detect a connection error
+            socket.getOutputStream().write(0);
+        } else {
+            socket = connect(SOCKET_NAME);
+        }
 
         DesktopConnection connection = new DesktopConnection(socket);
         Size videoSize = device.getScreenInfo().getVideoSize();

server/src/main/java/com/genymobile/scrcpy/Device.java

@@ -50,8 +50,8 @@ public final class Device {
         DisplayInfo displayInfo = serviceManager.getDisplayManager().getDisplayInfo();
         boolean rotated = (displayInfo.getRotation() & 1) != 0;
         Size deviceSize = displayInfo.getSize();
-        int w = deviceSize.getWidth();
-        int h = deviceSize.getHeight();
+        int w = deviceSize.getWidth() & ~7; // in case it's not a multiple of 8
+        int h = deviceSize.getHeight() & ~7;
         if (maxSize > 0) {
             if (BuildConfig.DEBUG && maxSize % 8 != 0) {
                 throw new AssertionError("Max size must be a multiple of 8");

server/src/main/java/com/genymobile/scrcpy/EventController.java

@@ -39,10 +39,6 @@ public class EventController {
         coords.orientation = 0;
         coords.pressure = 1;
         coords.size = 1;
-        coords.toolMajor = 1;
-        coords.toolMinor = 1;
-        coords.touchMajor = 1;
-        coords.touchMinor = 1;
     }
 
     private void setPointerCoords(Point point) {
@@ -167,10 +163,15 @@ public class EventController {
         return device.isScreenOn() || injectKeycode(KeyEvent.KEYCODE_POWER);
     }
 
+    private boolean pressBackOrTurnScreenOn() {
+        int keycode = device.isScreenOn() ? KeyEvent.KEYCODE_BACK : KeyEvent.KEYCODE_POWER;
+        return injectKeycode(keycode);
+    }
+
     private boolean executeCommand(int action) {
         switch (action) {
-            case ControlEvent.COMMAND_SCREEN_ON:
-                return turnScreenOn();
+            case ControlEvent.COMMAND_BACK_OR_SCREEN_ON:
+                return pressBackOrTurnScreenOn();
             default:
                 Ln.w("Unsupported command: " + action);
         }

server/src/main/java/com/genymobile/scrcpy/Options.java

@@ -3,6 +3,7 @@ package com.genymobile.scrcpy;
 public class Options {
     private int maxSize;
     private int bitRate;
+    private boolean tunnelForward;
 
     public int getMaxSize() {
         return maxSize;
@@ -19,4 +20,12 @@ public class Options {
     public void setBitRate(int bitRate) {
         this.bitRate = bitRate;
     }
+
+    public boolean isTunnelForward() {
+        return tunnelForward;
+    }
+
+    public void setTunnelForward(boolean tunnelForward) {
+        this.tunnelForward = tunnelForward;
+    }
 }

server/src/main/java/com/genymobile/scrcpy/Server.java

@@ -10,7 +10,8 @@ public final class Server {
 
     private static void scrcpy(Options options) throws IOException {
         final Device device = new Device(options);
-        try (DesktopConnection connection = DesktopConnection.open(device)) {
+        boolean tunnelForward = options.isTunnelForward();
+        try (DesktopConnection connection = DesktopConnection.open(device, tunnelForward)) {
             ScreenEncoder screenEncoder = new ScreenEncoder(options.getBitRate());
 
             // asynchronous
@@ -55,6 +56,13 @@ public final class Server {
         int bitRate = Integer.parseInt(args[1]);
         options.setBitRate(bitRate);
 
+        if (args.length < 3) {
+            return options;
+        }
+        // use "adb forward" instead of "adb tunnel"? (so the server must listen)
+        boolean tunnelForward = Boolean.parseBoolean(args[2]);
+        options.setTunnelForward(tunnelForward);
+
         return options;
     }
 

server/src/test/java/com/genymobile/scrcpy/ControlEventReaderTest.java

@@ -3,14 +3,15 @@ package com.genymobile.scrcpy;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
 
-import org.junit.Assert;
-import org.junit.Test;
-
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+
+import org.junit.Assert;
+import org.junit.Test;
 
 public class ControlEventReaderTest {
 
@@ -43,8 +44,8 @@ public class ControlEventReaderTest {
         DataOutputStream dos = new DataOutputStream(bos);
         dos.writeByte(ControlEvent.TYPE_TEXT);
         byte[] text = "testé".getBytes(StandardCharsets.UTF_8);
-        dos.writeByte(text.length);
-        dos.write("testé".getBytes(StandardCharsets.UTF_8));
+        dos.writeShort(text.length);
+        dos.write(text);
         byte[] packet = bos.toByteArray();
 
         reader.readFrom(new ByteArrayInputStream(packet));
@@ -54,6 +55,26 @@ public class ControlEventReaderTest {
         Assert.assertEquals("testé", event.getText());
     }
 
+    @Test
+    public void testParseLongTextEvent() throws IOException {
+        ControlEventReader reader = new ControlEventReader();
+
+        ByteArrayOutputStream bos = new ByteArrayOutputStream();
+        DataOutputStream dos = new DataOutputStream(bos);
+        dos.writeByte(ControlEvent.TYPE_TEXT);
+        byte[] text = new byte[ControlEventReader.TEXT_MAX_LENGTH];
+        Arrays.fill(text, (byte) 'a');
+        dos.writeShort(text.length);
+        dos.write(text);
+        byte[] packet = bos.toByteArray();
+
+        reader.readFrom(new ByteArrayInputStream(packet));
+        ControlEvent event = reader.next();
+
+        Assert.assertEquals(ControlEvent.TYPE_TEXT, event.getType());
+        Assert.assertEquals(new String(text, StandardCharsets.US_ASCII), event.getText());
+    }
+
     @Test
     public void testParseMouseEvent() throws IOException {
         ControlEventReader reader = new ControlEventReader();