# ========================================================================== # # # # KVMD - The main Pi-KVM daemon. # # # # Copyright (C) 2020 Maxim Devaev # # # # 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 . # # # # ========================================================================== # 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}")