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Most of docs/barrier.txt is describing the protocol implemented by the input-barrier device. Move this into the interop section of the manual, and rstify it. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-id: 20210727204112.12579-2-peter.maydell@linaro.org
427 lines
9.2 KiB
ReStructuredText
427 lines
9.2 KiB
ReStructuredText
Barrier client protocol
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=======================
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QEMU's ``input-barrier`` device implements the client end of
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the KVM (Keyboard-Video-Mouse) software
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`Barrier <https://github.com/debauchee/barrier>`__.
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This document briefly describes the protocol as we implement it.
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Message format
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--------------
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Message format between the server and client is in two parts:
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#. the payload length, a 32bit integer in network endianness
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#. the payload
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The payload starts with a 4byte string (without NUL) which is the
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command. The first command between the server and the client
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is the only command not encoded on 4 bytes ("Barrier").
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The remaining part of the payload is decoded according to the command.
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Protocol Description
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--------------------
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This comes from ``barrier/src/lib/barrier/protocol_types.h``.
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barrierCmdHello "Barrier"
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^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t minor, int16_t major }``
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Description:
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Say hello to client
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``minor`` = protocol major version number supported by server
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``major`` = protocol minor version number supported by server
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barrierCmdHelloBack "Barrier"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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client ->server
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Parameters:
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``{ int16_t minor, int16_t major, char *name}``
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Description:
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Respond to hello from server
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``minor`` = protocol major version number supported by client
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``major`` = protocol minor version number supported by client
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``name`` = client name
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barrierCmdDInfo "DINF"
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^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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client ->server
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Parameters:
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``{ int16_t x_origin, int16_t y_origin, int16_t width, int16_t height, int16_t x, int16_t y}``
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Description:
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The client screen must send this message in response to the
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barrierCmdQInfo message. It must also send this message when the
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screen's resolution changes. In this case, the client screen should
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ignore any barrierCmdDMouseMove messages until it receives a
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barrierCmdCInfoAck in order to prevent attempts to move the mouse off
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the new screen area.
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barrierCmdCNoop "CNOP"
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^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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client -> server
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Parameters:
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None
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Description:
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No operation
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barrierCmdCClose "CBYE"
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^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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None
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Description:
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Close connection
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barrierCmdCEnter "CINN"
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^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t x, int16_t y, int32_t seq, int16_t modifier }``
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Description:
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Enter screen.
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``x``, ``y`` = entering screen absolute coordinates
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``seq`` = sequence number, which is used to order messages between
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screens. the secondary screen must return this number
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with some messages
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``modifier`` = modifier key mask. this will have bits set for each
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toggle modifier key that is activated on entry to the
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screen. the secondary screen should adjust its toggle
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modifiers to reflect that state.
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barrierCmdCLeave "COUT"
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^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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None
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Description:
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Leaving screen. the secondary screen should send clipboard data in
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response to this message for those clipboards that it has grabbed
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(i.e. has sent a barrierCmdCClipboard for and has not received a
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barrierCmdCClipboard for with a greater sequence number) and that
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were grabbed or have changed since the last leave.
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barrierCmdCClipboard "CCLP"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int8_t id, int32_t seq }``
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Description:
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Grab clipboard. Sent by screen when some other app on that screen
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grabs a clipboard.
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``id`` = the clipboard identifier
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``seq`` = sequence number. Client must use the sequence number passed in
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the most recent barrierCmdCEnter. the server always sends 0.
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barrierCmdCScreenSaver "CSEC"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int8_t started }``
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Description:
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Screensaver change.
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``started`` = Screensaver on primary has started (1) or closed (0)
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barrierCmdCResetOptions "CROP"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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None
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Description:
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Reset options. Client should reset all of its options to their
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defaults.
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barrierCmdCInfoAck "CIAK"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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None
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Description:
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Resolution change acknowledgment. Sent by server in response to a
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client screen's barrierCmdDInfo. This is sent for every
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barrierCmdDInfo, whether or not the server had sent a barrierCmdQInfo.
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barrierCmdCKeepAlive "CALV"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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None
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Description:
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Keep connection alive. Sent by the server periodically to verify
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that connections are still up and running. clients must reply in
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kind on receipt. if the server gets an error sending the message or
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does not receive a reply within a reasonable time then the server
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disconnects the client. if the client doesn't receive these (or any
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message) periodically then it should disconnect from the server. the
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appropriate interval is defined by an option.
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barrierCmdDKeyDown "DKDN"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t keyid, int16_t modifier [,int16_t button] }``
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Description:
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Key pressed.
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``keyid`` = X11 key id
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``modified`` = modified mask
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``button`` = X11 Xkb keycode (optional)
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barrierCmdDKeyRepeat "DKRP"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t keyid, int16_t modifier, int16_t repeat [,int16_t button] }``
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Description:
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Key auto-repeat.
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``keyid`` = X11 key id
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``modified`` = modified mask
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``repeat`` = number of repeats
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``button`` = X11 Xkb keycode (optional)
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barrierCmdDKeyUp "DKUP"
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^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t keyid, int16_t modifier [,int16_t button] }``
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Description:
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Key released.
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``keyid`` = X11 key id
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``modified`` = modified mask
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``button`` = X11 Xkb keycode (optional)
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barrierCmdDMouseDown "DMDN"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int8_t button }``
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Description:
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Mouse button pressed.
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``button`` = button id
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barrierCmdDMouseUp "DMUP"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int8_t button }``
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Description:
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Mouse button release.
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``button`` = button id
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barrierCmdDMouseMove "DMMV"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t x, int16_t y }``
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Description:
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Absolute mouse moved.
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``x``, ``y`` = absolute screen coordinates
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barrierCmdDMouseRelMove "DMRM"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t x, int16_t y }``
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Description:
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Relative mouse moved.
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``x``, ``y`` = r relative screen coordinates
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barrierCmdDMouseWheel "DMWM"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t x , int16_t y }`` or ``{ int16_t y }``
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Description:
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Mouse scroll. The delta should be +120 for one tick forward (away
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from the user) or right and -120 for one tick backward (toward the
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user) or left.
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``x`` = x delta
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``y`` = y delta
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barrierCmdDClipboard "DCLP"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int8_t id, int32_t seq, int8_t mark, char *data }``
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Description:
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Clipboard data.
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``id`` = clipboard id
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``seq`` = sequence number. The sequence number is 0 when sent by the
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server. Client screens should use the/ sequence number from
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the most recent barrierCmdCEnter.
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barrierCmdDSetOptions "DSOP"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int32 t nb, { int32_t id, int32_t val }[] }``
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Description:
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Set options. Client should set the given option/value pairs.
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``nb`` = numbers of ``{ id, val }`` entries
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``id`` = option id
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``val`` = option new value
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barrierCmdDFileTransfer "DFTR"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int8_t mark, char *content }``
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Description:
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Transfer file data.
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* ``mark`` = 0 means the content followed is the file size
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* 1 means the content followed is the chunk data
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* 2 means the file transfer is finished
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barrierCmdDDragInfo "DDRG"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t nb, char *content }``
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Description:
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Drag information.
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``nb`` = number of dragging objects
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``content`` = object's directory
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barrierCmdQInfo "QINF"
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^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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None
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Description:
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Query screen info
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Client should reply with a barrierCmdDInfo
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barrierCmdEIncompatible "EICV"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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``{ int16_t nb, major *minor }``
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Description:
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Incompatible version.
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``major`` = major version
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``minor`` = minor version
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barrierCmdEBusy "EBSY"
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^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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None
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Description:
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Name provided when connecting is already in use.
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barrierCmdEUnknown "EUNK"
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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None
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Description:
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Unknown client. Name provided when connecting is not in primary's
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screen configuration map.
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barrierCmdEBad "EBAD"
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^^^^^^^^^^^^^^^^^^^^^^^
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Direction:
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server -> client
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Parameters:
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None
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Description:
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Protocol violation. Server should disconnect after sending this
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message.
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