pikvm/pikvm#1420: VNC: Ignore CUT event 3 seconds after connection

kvmd/apps/__init__.py

@@ -667,9 +667,10 @@ def _get_config_scheme() -> dict:
         },
 
         "vnc": {
-            "desired_fps":  Option(30, type=valid_stream_fps),
-            "mouse_output": Option("usb", type=valid_hid_mouse_output),
-            "keymap":       Option("/usr/share/kvmd/keymaps/en-us", type=valid_abs_file),
+            "desired_fps":     Option(30, type=valid_stream_fps),
+            "mouse_output":    Option("usb", type=valid_hid_mouse_output),
+            "keymap":          Option("/usr/share/kvmd/keymaps/en-us", type=valid_abs_file),
+            "allow_cut_after": Option(3.0, type=valid_float_f0),
 
             "server": {
                 "host":        Option("",   type=valid_ip_or_host, if_empty=""),

kvmd/apps/vnc/__init__.py

@@ -71,6 +71,7 @@ def main(argv: (list[str] | None)=None) -> None:
         desired_fps=config.desired_fps,
         mouse_output=config.mouse_output,
         keymap_path=config.keymap,
+        allow_cut_after=config.allow_cut_after,
 
         kvmd=KvmdClient(user_agent=user_agent, **config.kvmd._unpack()),
         streamers=streamers,

kvmd/apps/vnc/rfb/__init__.py

@@ -22,6 +22,7 @@
 
 import asyncio
 import ssl
+import time
 
 from typing import Callable
 from typing import Coroutine
@@ -64,6 +65,7 @@ class RfbClient(RfbClientStream):  # pylint: disable=too-many-instance-attribute
         width: int,
         height: int,
         name: str,
+        allow_cut_after: float,
         vnc_passwds: list[str],
         vencrypt: bool,
         none_auth_only: bool,
@@ -79,6 +81,7 @@ class RfbClient(RfbClientStream):  # pylint: disable=too-many-instance-attribute
         self._width = width
         self._height = height
         self.__name = name
+        self.__allow_cut_after = allow_cut_after
         self.__vnc_passwds = vnc_passwds
         self.__vencrypt = vencrypt
         self.__none_auth_only = none_auth_only
@@ -90,6 +93,8 @@ class RfbClient(RfbClientStream):  # pylint: disable=too-many-instance-attribute
         self.__fb_cont_updates = False
         self.__fb_reset_h264 = False
 
+        self.__allow_cut_since_ts = 0.0
+
         self.__lock = asyncio.Lock()
 
     # =====
@@ -414,6 +419,7 @@ class RfbClient(RfbClientStream):  # pylint: disable=too-many-instance-attribute
     # =====
 
     async def __main_loop(self) -> None:
+        self.__allow_cut_since_ts = time.monotonic() + self.__allow_cut_after
         handlers = {
             0: self.__handle_set_pixel_format,
             2: self.__handle_set_encodings,
@@ -499,7 +505,12 @@ class RfbClient(RfbClientStream):  # pylint: disable=too-many-instance-attribute
     async def __handle_client_cut_text(self) -> None:
         length = (await self._read_struct("cut text length", "xxx L"))[0]
         text = await self._read_text("cut text data", length)
-        await self._on_cut_event(text)
+        if self.__allow_cut_since_ts > 0 and time.monotonic() >= self.__allow_cut_since_ts:
+            # We should ignore cut event a few seconds after handshake
+            # because bVNC, AVNC and maybe some other clients perform
+            # it right after the connection automatically.
+            #   - https://github.com/pikvm/pikvm/issues/1420
+            await self._on_cut_event(text)
 
     async def __handle_enable_cont_updates(self) -> None:
         enabled = bool((await self._read_struct("enabled ContUpdates", "B HH HH"))[0])

kvmd/apps/vnc/server.py

@@ -81,6 +81,7 @@ class _Client(RfbClient):  # pylint: disable=too-many-instance-attributes
         mouse_output: str,
         keymap_name: str,
         symmap: dict[int, dict[int, str]],
+        allow_cut_after: float,
 
         kvmd: KvmdClient,
         streamers: list[BaseStreamerClient],
@@ -100,6 +101,7 @@ class _Client(RfbClient):  # pylint: disable=too-many-instance-attributes
             tls_timeout=tls_timeout,
             x509_cert_path=x509_cert_path,
             x509_key_path=x509_key_path,
+            allow_cut_after=allow_cut_after,
             vnc_passwds=list(vnc_credentials),
             vencrypt=vencrypt,
             none_auth_only=none_auth_only,
@@ -444,6 +446,7 @@ class VncServer:  # pylint: disable=too-many-instance-attributes
         desired_fps: int,
         mouse_output: str,
         keymap_path: str,
+        allow_cut_after: float,
 
         kvmd: KvmdClient,
         streamers: list[BaseStreamerClient],
@@ -501,6 +504,7 @@ class VncServer:  # pylint: disable=too-many-instance-attributes
                     mouse_output=mouse_output,
                     keymap_name=keymap_name,
                     symmap=symmap,
+                    allow_cut_after=allow_cut_after,
                     kvmd=kvmd,
                     streamers=streamers,
                     vnc_credentials=(await self.__vnc_auth_manager.read_credentials())[0],