refactoring

4 files changed, 541 insertions, 0 deletions

diff --git a/kvmd/apps/vnc/rfb/__init__.py b/kvmd/apps/vnc/rfb/__init__.py
new file mode 100644
index 00000000..8dfb6fe2
--- /dev/null
+++ b/kvmd/apps/vnc/rfb/__init__.py
@@ -0,0 +1,334 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2020  Maxim Devaev <[email protected]>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+import asyncio
+
+from typing import Dict
+from typing import Coroutine
+
+from ....logging import get_logger
+
+from .... import aiotools
+
+from .errors import RfbError
+from .errors import RfbConnectionError
+
+from .encodings import RfbEncodings
+from .encodings import RfbClientEncodings
+
+from .stream import RfbClientStream
+
+
+# =====
+class RfbClient(RfbClientStream):
+    # https://github.com/rfbproto/rfbproto/blob/master/rfbproto.rst
+    # https://www.toptal.com/java/implementing-remote-framebuffer-server-java
+    # https://github.com/TigerVNC/tigervnc
+
+    def __init__(
+        self,
+        reader: asyncio.StreamReader,
+        writer: asyncio.StreamWriter,
+
+        width: int,
+        height: int,
+        name: str,
+    ) -> None:
+
+        super().__init__(reader, writer)
+
+        self._width = width
+        self._height = height
+        self._name = name
+
+        self._encodings = RfbClientEncodings(frozenset())
+
+        self._lock = asyncio.Lock()
+
+        get_logger(0).info("Connected client: %s", self._remote)
+
+    # =====
+
+    async def _run(self, **coros: Coroutine) -> None:
+        tasks = list(map(asyncio.create_task, [
+            self.__wrapper(name, coro)
+            for (name, coro) in {"main": self.__main_task_loop(), **coros}.items()
+        ]))
+        try:
+            await aiotools.wait_first(*tasks)
+        finally:
+            for task in tasks:
+                task.cancel()
+
+    async def __wrapper(self, name: str, coro: Coroutine) -> None:
+        logger = get_logger(0)
+        try:
+            await coro
+            raise RuntimeError("Subtask just finished without any exception")
+        except asyncio.CancelledError:
+            logger.info("[%s] Client %s: Cancelling ...", name, self._remote)
+            raise
+        except RfbConnectionError as err:
+            logger.info("[%s] Client %s: Gone (%s): Disconnected", name, self._remote, str(err))
+        except RfbError as err:
+            logger.info("[%s] Client %s: %s: Disconnected", name, self._remote, str(err))
+        except Exception:
+            logger.exception("[%s] Unhandled exception with client %s: Disconnected", name, self._remote)
+
+    async def __main_task_loop(self) -> None:
+        try:
+            rfb_version = await self.__handshake_version()
+            await self.__handshake_security(rfb_version)
+            await self.__handshake_init()
+            await self.__main_loop()
+        finally:
+            self._close()
+
+    # =====
+
+    async def _authorize(self, user: str, passwd: str) -> bool:
+        raise NotImplementedError
+
+    async def _on_key_event(self, code: int, state: bool) -> None:
+        raise NotImplementedError
+
+    async def _on_pointer_event(self, buttons: Dict[str, bool], wheel: Dict[str, int], move: Dict[str, int]) -> None:
+        raise NotImplementedError
+
+    async def _on_cut_event(self, text: str) -> None:
+        raise NotImplementedError
+
+    async def _on_set_encodings(self) -> None:
+        raise NotImplementedError
+
+    async def _on_fb_update_request(self) -> None:
+        raise NotImplementedError
+
+    # =====
+
+    async def _send_fb(self, jpeg: bytes) -> None:
+        assert self._encodings.has_tight
+        assert self._encodings.tight_jpeg_quality > 0
+        assert len(jpeg) <= 4194303, len(jpeg)
+        await self._write_fb_update(self._width, self._height, RfbEncodings.TIGHT, drain=False)
+        length = len(jpeg)
+        if length <= 127:
+            await self._write_struct("", bytes([0b10011111, length & 0x7F]), jpeg)
+        elif length <= 16383:
+            await self._write_struct("", bytes([0b10011111, length & 0x7F | 0x80, length >> 7 & 0x7F]), jpeg)
+        else:
+            await self._write_struct("", bytes([0b10011111, length & 0x7F | 0x80, length >> 7 & 0x7F | 0x80, length >> 14 & 0xFF]), jpeg)
+
+    async def _send_resize(self, width: int, height: int) -> None:
+        assert self._encodings.has_resize
+        await self._write_fb_update(width, height, RfbEncodings.RESIZE)
+        self._width = width
+        self._height = height
+
+    async def _send_rename(self, name: str) -> None:
+        assert self._encodings.has_rename
+        await self._write_fb_update(0, 0, RfbEncodings.RENAME, drain=False)
+        await self._write_reason(name)
+        self._name = name
+
+    async def _send_leds_state(self, caps: bool, scroll: bool, num: bool) -> None:
+        assert self._encodings.has_leds_state
+        await self._write_fb_update(0, 0, RfbEncodings.LEDS_STATE, drain=False)
+        await self._write_struct("B", 0x1 & scroll | 0x2 & num | 0x4 & caps)
+
+    # =====
+
+    async def __handshake_version(self) -> int:
+        # The only published protocol versions at this time are 3.3, 3.7, 3.8.
+        # Version 3.5 was wrongly reported by some clients, but it should be
+        # interpreted by all servers as 3.3
+
+        await self._write_struct("", b"RFB 003.008\n")
+
+        response = await self._read_text(12)
+        if (
+            not response.startswith("RFB 003.00")
+            or not response.endswith("\n")
+            or response[-2] not in ["3", "5", "7", "8"]
+        ):
+            raise RfbError(f"Invalid version response: {response!r}")
+
+        try:
+            version = int(response[-2])
+        except ValueError:
+            raise RfbError(f"Invalid version response: {response!r}")
+        return (3 if version == 5 else version)
+
+    # =====
+
+    async def __handshake_security(self, rfb_version: int) -> None:
+        if rfb_version == 3:
+            await self.__handshake_security_v3(rfb_version)
+        else:
+            await self.__handshake_security_v7_plus(rfb_version)
+
+    async def __handshake_security_v3(self, rfb_version: int) -> None:
+        assert rfb_version == 3
+
+        await self._write_struct("L", 0, drain=False)  # Refuse old clients using the invalid security type
+        msg = "The client uses a very old protocol 3.3; required 3.7 at least"
+        await self._write_reason(msg)
+        raise RfbError(msg)
+
+    async def __handshake_security_v7_plus(self, rfb_version: int) -> None:
+        assert rfb_version >= 7
+
+        vencrypt = 19
+        await self._write_struct("B B", 1, vencrypt)  # One security type, VeNCrypt
+
+        security_type = await self._read_number("B")
+        if security_type != vencrypt:
+            raise RfbError(f"Invalid security type: {security_type}; expected VeNCrypt({vencrypt})")
+
+        # -----
+
+        await self._write_struct("BB", 0, 2)  # VeNCrypt 0.2
+
+        vencrypt_version = "%d.%d" % (await self._read_struct("BB"))
+        if vencrypt_version != "0.2":
+            await self._write_struct("B", 1)  # Unsupported
+            raise RfbError(f"Unsupported VeNCrypt version: {vencrypt_version}")
+
+        await self._write_struct("B", 0)
+
+        # -----
+
+        plain = 256
+        await self._write_struct("B L", 1, plain)  # One auth subtype, plain
+
+        auth_type = await self._read_number("L")
+        if auth_type != plain:
+            raise RfbError(f"Invalid auth type: {auth_type}; expected Plain({plain})")
+
+        # -----
+
+        (user_length, passwd_length) = await self._read_struct("LL")
+        user = await self._read_text(user_length)
+        passwd = await self._read_text(passwd_length)
+
+        if (await self._authorize(user, passwd)):
+            get_logger(0).info("[main] Client %s: Access granted for user %r", self._remote, user)
+            await self._write_struct("L", 0)
+        else:
+            await self._write_struct("L", 1, drain=(rfb_version < 8))
+            if rfb_version >= 8:
+                await self._write_reason("Invalid username or password")
+            raise RfbError(f"Access denied for user {user!r}")
+
+    # =====
+
+    async def __handshake_init(self) -> None:
+        await self._read_number("B")  # Shared flag, ignored
+
+        await self._write_struct("HH", self._width, self._height, drain=False)
+        await self._write_struct(
+            "BB?? HHH BBB xxx",
+            32,     # Bits per pixel
+            24,     # Depth
+            False,  # Big endian
+            True,   # True color
+            255,    # Red max
+            255,    # Green max
+            255,    # Blue max
+            16,     # Red shift
+            8,      # Green shift
+            0,      # Blue shift
+            drain=False,
+        )
+        await self._write_reason(self._name)
+
+    # =====
+
+    async def __main_loop(self) -> None:
+        handlers = {
+            0: self.__handle_set_pixel_format,
+            2: self.__handle_set_encodings,
+            3: self.__handle_fb_update_request,
+            4: self.__handle_key_event,
+            5: self.__handle_pointer_event,
+            6: self.__handle_client_cut_text,
+        }
+        while True:
+            msg_type = await self._read_number("B")
+            if (handler := handlers.get(msg_type)) is not None:  # noqa: E203,E231
+                await handler()  # type: ignore  # mypy bug
+            else:
+                raise RfbError(f"Unknown message type: {msg_type}")
+
+    async def __handle_set_pixel_format(self) -> None:
+        # JpegCompression may only be used when bits-per-pixel is either 16 or 32
+        bits_per_pixel = (await self._read_struct("xxx BB?? HHH BBB xxx"))[0]
+        if bits_per_pixel not in [16, 32]:
+            raise RfbError(f"Requested unsupported {bits_per_pixel=} for Tight JPEG; required 16 or 32")
+
+    async def __handle_set_encodings(self) -> None:
+        encodings_count = (await self._read_struct("x H"))[0]
+        if encodings_count > 1024:
+            raise RfbError(f"Too many encodings: {encodings_count}")
+        self._encodings = RfbClientEncodings(frozenset(await self._read_struct("l" * encodings_count)))
+        get_logger(0).info("[main] Client %s: Features: resize=%d; rename=%d; leds=%d",
+                           self._remote, self._encodings.has_resize, self._encodings.has_rename, self._encodings.has_leds_state)
+        self.__check_tight_jpeg()
+        await self._on_set_encodings()
+
+    async def __handle_fb_update_request(self) -> None:
+        self.__check_tight_jpeg()  # If we don't receive SetEncodings from client
+        await self._read_struct("? HH HH")  # Ignore any arguments, just perform the full update
+        await self._on_fb_update_request()
+
+    async def __handle_key_event(self) -> None:
+        (state, code) = await self._read_struct("? xx L")
+        await self._on_key_event(code, state)  # type: ignore
+
+    async def __handle_pointer_event(self) -> None:
+        (buttons, to_x, to_y) = await self._read_struct("B HH")
+        await self._on_pointer_event(
+            buttons={
+                "left": bool(buttons & 0x1),
+                "right": bool(buttons & 0x4),
+                "middle": bool(buttons & 0x2),
+            },
+            wheel={
+                "x": (-4 if buttons & 0x40 else (4 if buttons & 0x20 else 0)),
+                "y": (-4 if buttons & 0x10 else (4 if buttons & 0x8 else 0)),
+            },
+            move={
+                "x": round(to_x / self._width * 65535 + -32768),
+                "y": round(to_y / self._height * 65535 + -32768),
+            },
+        )
+
+    async def __handle_client_cut_text(self) -> None:
+        length = (await self._read_struct("xxx L"))[0]
+        text = await self._read_text(length)
+        await self._on_cut_event(text)
+
+    def __check_tight_jpeg(self) -> None:
+        # JpegCompression may only be used when the client has advertized
+        # a quality level using the JPEG Quality Level Pseudo-encoding
+        if not self._encodings.has_tight or self._encodings.tight_jpeg_quality == 0:
+            raise RfbError(f"Tight JPEG encoding is not supported by client: {self._encodings}")
diff --git a/kvmd/apps/vnc/rfb/encodings.py b/kvmd/apps/vnc/rfb/encodings.py
new file mode 100644
index 00000000..cb1d4761
--- /dev/null
+++ b/kvmd/apps/vnc/rfb/encodings.py
@@ -0,0 +1,69 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2020  Maxim Devaev <[email protected]>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+import dataclasses
+
+from typing import FrozenSet
+from typing import Any
+
+
+# =====
+class RfbEncodings:
+    RESIZE = -223  # DesktopSize Pseudo-encoding
+    RENAME = -307  # DesktopName Pseudo-encoding
+    LEDS_STATE = -261  # LED State Pseudo-encoding
+
+    TIGHT = 7
+    TIGHT_JPEG_QUALITIES = dict(zip(  # JPEG Quality Level Pseudo-encoding
+        [-32, -31, -30, -29, -28, -27, -26, -25, -24, -23],
+        [10,   20,  30,  40,  50,  60,  70,  80,  90, 100],
+    ))
+
+
[email protected](frozen=True)
+class RfbClientEncodings:
+    encodings: FrozenSet[int]
+
+    has_resize: bool = dataclasses.field(default=False)
+    has_rename: bool = dataclasses.field(default=False)
+    has_leds_state: bool = dataclasses.field(default=False)
+
+    has_tight: bool = dataclasses.field(default=False)
+    tight_jpeg_quality: int = dataclasses.field(default=0)
+
+    def __post_init__(self) -> None:
+        self.__set("has_resize", (RfbEncodings.RESIZE in self.encodings))
+        self.__set("has_rename", (RfbEncodings.RENAME in self.encodings))
+        self.__set("has_leds_state", (RfbEncodings.LEDS_STATE in self.encodings))
+
+        self.__set("has_tight", (RfbEncodings.TIGHT in self.encodings))
+        self.__set("tight_jpeg_quality", self.__get_tight_jpeg_quality())
+
+    def __set(self, key: str, value: Any) -> None:
+        object.__setattr__(self, key, value)
+
+    def __get_tight_jpeg_quality(self) -> int:
+        if RfbEncodings.TIGHT in self.encodings:
+            qualities = self.encodings.intersection(RfbEncodings.TIGHT_JPEG_QUALITIES)
+            if qualities:
+                return RfbEncodings.TIGHT_JPEG_QUALITIES[max(qualities)]
+        return 0
diff --git a/kvmd/apps/vnc/rfb/errors.py b/kvmd/apps/vnc/rfb/errors.py
new file mode 100644
index 00000000..d53bf1a4
--- /dev/null
+++ b/kvmd/apps/vnc/rfb/errors.py
@@ -0,0 +1,29 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2020  Maxim Devaev <[email protected]>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+class RfbError(Exception):
+    pass
+
+
+class RfbConnectionError(RfbError):
+    def __init__(self, err: Exception) -> None:
+        super().__init__(type(err).__name__)
diff --git a/kvmd/apps/vnc/rfb/stream.py b/kvmd/apps/vnc/rfb/stream.py
new file mode 100644
index 00000000..843cfe54
--- /dev/null
+++ b/kvmd/apps/vnc/rfb/stream.py
@@ -0,0 +1,109 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main Pi-KVM daemon.                                          #
+#                                                                            #
+#    Copyright (C) 2020  Maxim Devaev <[email protected]>                    #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+import asyncio
+import struct
+
+from typing import Tuple
+from typing import Any
+
+from .errors import RfbConnectionError
+
+
+# =====
+class RfbClientStream:
+    def __init__(self, reader: asyncio.StreamReader, writer: asyncio.StreamWriter) -> None:
+        self.__reader = reader
+        self.__writer = writer
+
+        self._remote = "[%s]:%d" % (self.__writer.transport.get_extra_info("peername")[:2])
+
+    # =====
+
+    async def _read_number(self, fmt: str) -> int:
+        assert len(fmt) == 1
+        try:
+            if fmt == "B":
+                return (await self.__reader.readexactly(1))[0]
+            else:
+                fmt = f">{fmt}"
+                return struct.unpack(fmt, await self.__reader.readexactly(struct.calcsize(fmt)))[0]
+        except (ConnectionError, asyncio.IncompleteReadError) as err:
+            raise RfbConnectionError(err)
+
+    async def _read_struct(self, fmt: str) -> Tuple[int, ...]:
+        assert len(fmt) > 1
+        try:
+            fmt = f">{fmt}"
+            return struct.unpack(fmt, (await self.__reader.readexactly(struct.calcsize(fmt))))
+        except (ConnectionError, asyncio.IncompleteReadError) as err:
+            raise RfbConnectionError(err)
+
+    async def _read_text(self, length: int) -> str:
+        try:
+            return (await self.__reader.readexactly(length)).decode("utf-8", errors="ignore")
+        except (ConnectionError, asyncio.IncompleteReadError) as err:
+            raise RfbConnectionError(err)
+
+    # =====
+
+    async def _write_struct(self, fmt: str, *values: Any, drain: bool=True) -> None:
+        try:
+            if not fmt:
+                for value in values:
+                    self.__writer.write(value)
+            elif fmt == "B":
+                assert len(values) == 1
+                self.__writer.write(bytes([values[0]]))
+            else:
+                self.__writer.write(struct.pack(f">{fmt}", *values))
+            if drain:
+                await self.__writer.drain()
+        except ConnectionError as err:
+            raise RfbConnectionError(err)
+
+    async def _write_reason(self, text: str, drain: bool=True) -> None:
+        encoded = text.encode("utf-8", errors="ignore")
+        await self._write_struct("L", len(encoded), drain=False)
+        try:
+            self.__writer.write(encoded)
+            if drain:
+                await self.__writer.drain()
+        except ConnectionError as err:
+            raise RfbConnectionError(err)
+
+    async def _write_fb_update(self, width: int, height: int, encoding: int, drain: bool=True) -> None:
+        await self._write_struct(
+            "BxH HH HH l",
+            0,  # FB update
+            1,  # Number of rects
+            0, 0, width, height, encoding,
+            drain=drain,
+        )
+
+    # =====
+
+    def _close(self) -> None:
+        try:
+            self.__writer.close()
+        except Exception:
+            pass