| QEMU Barrier Client |
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| * About |
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| Barrier is a KVM (Keyboard-Video-Mouse) software forked from Symless's |
| synergy 1.9 codebase. |
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| See https://github.com/debauchee/barrier |
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| * QEMU usage |
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| Generally, mouse and keyboard are grabbed through the QEMU video |
| interface emulation. |
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| But when we want to use a video graphic adapter via a PCI passthrough |
| there is no way to provide the keyboard and mouse inputs to the VM |
| except by plugging a second set of mouse and keyboard to the host |
| or by installing a KVM software in the guest OS. |
| |
| The QEMU Barrier client avoids this by implementing directly the Barrier |
| protocol into QEMU. |
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| This protocol is enabled by adding an input-barrier object to QEMU. |
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| Syntax: input-barrier,id=<object-id>,name=<guest display name> |
| [,server=<barrier server address>][,port=<barrier server port>] |
| [,x-origin=<x-origin>][,y-origin=<y-origin>] |
| [,width=<width>][,height=<height>] |
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| The object can be added on the QEMU command line, for instance with: |
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| ... -object input-barrier,id=barrier0,name=VM-1 ... |
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| where VM-1 is the name the display configured int the Barrier server |
| on the host providing the mouse and the keyboard events. |
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| by default <barrier server address> is "localhost", port is 24800, |
| <x-origin> and <y-origin> are set to 0, <width> and <height> to |
| 1920 and 1080. |
| |
| If Barrier server is stopped QEMU needs to be reconnected manually, |
| by removing and re-adding the input-barrier object, for instance |
| with the help of the HMP monitor: |
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| (qemu) object_del barrier0 |
| (qemu) object_add input-barrier,id=barrier0,name=VM-1 |
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| * Message format |
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| Message format between the server and client is in two parts: |
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| 1- the payload length is a 32bit integer in network endianness, |
| 2- the payload |
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| The payload starts with a 4byte string (without NUL) which is the |
| command. The first command between the server and the client |
| is the only command not encoded on 4 bytes ("Barrier"). |
| The remaining part of the payload is decoded according to the command. |
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| * Protocol Description (from barrier/src/lib/barrier/protocol_types.h) |
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| - barrierCmdHello "Barrier" |
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| Direction: server -> client |
| Parameters: { int16_t minor, int16_t major } |
| Description: |
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| Say hello to client |
| minor = protocol major version number supported by server |
| major = protocol minor version number supported by server |
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| - barrierCmdHelloBack "Barrier" |
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| Direction: client ->server |
| Parameters: { int16_t minor, int16_t major, char *name} |
| Description: |
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| Respond to hello from server |
| minor = protocol major version number supported by client |
| major = protocol minor version number supported by client |
| name = client name |
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| - barrierCmdDInfo "DINF" |
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| Direction: client ->server |
| Parameters: { int16_t x_origin, int16_t y_origin, int16_t width, int16_t height, int16_t x, int16_t y} |
| Description: |
| |
| The client screen must send this message in response to the |
| barrierCmdQInfo message. It must also send this message when the |
| screen's resolution changes. In this case, the client screen should |
| ignore any barrierCmdDMouseMove messages until it receives a |
| barrierCmdCInfoAck in order to prevent attempts to move the mouse off |
| the new screen area. |
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| - barrierCmdCNoop "CNOP" |
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| Direction: client -> server |
| Parameters: None |
| Description: |
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| No operation |
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| - barrierCmdCClose "CBYE" |
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| Direction: server -> client |
| Parameters: None |
| Description: |
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| Close connection |
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| - barrierCmdCEnter "CINN" |
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| Direction: server -> client |
| Parameters: { int16_t x, int16_t y, int32_t seq, int16_t modifier } |
| Description: |
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| Enter screen. |
| x,y = entering screen absolute coordinates |
| seq = sequence number, which is used to order messages between |
| screens. the secondary screen must return this number |
| with some messages |
| modifier = modifier key mask. this will have bits set for each |
| toggle modifier key that is activated on entry to the |
| screen. the secondary screen should adjust its toggle |
| modifiers to reflect that state. |
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| - barrierCmdCLeave "COUT" |
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| Direction: server -> client |
| Parameters: None |
| Description: |
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| Leaving screen. the secondary screen should send clipboard data in |
| response to this message for those clipboards that it has grabbed |
| (i.e. has sent a barrierCmdCClipboard for and has not received a |
| barrierCmdCClipboard for with a greater sequence number) and that |
| were grabbed or have changed since the last leave. |
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| - barrierCmdCClipboard "CCLP" |
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| Direction: server -> client |
| Parameters: { int8_t id, int32_t seq } |
| Description: |
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| Grab clipboard. Sent by screen when some other app on that screen |
| grabs a clipboard. |
| id = the clipboard identifier |
| seq = sequence number. Client must use the sequence number passed in |
| the most recent barrierCmdCEnter. the server always sends 0. |
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| - barrierCmdCScreenSaver "CSEC" |
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| Direction: server -> client |
| Parameters: { int8_t started } |
| Description: |
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| Screensaver change. |
| started = Screensaver on primary has started (1) or closed (0) |
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| - barrierCmdCResetOptions "CROP" |
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| Direction: server -> client |
| Parameters: None |
| Description: |
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| Reset options. Client should reset all of its options to their |
| defaults. |
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| - barrierCmdCInfoAck "CIAK" |
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| Direction: server -> client |
| Parameters: None |
| Description: |
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| Resolution change acknowledgment. Sent by server in response to a |
| client screen's barrierCmdDInfo. This is sent for every |
| barrierCmdDInfo, whether or not the server had sent a barrierCmdQInfo. |
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| - barrierCmdCKeepAlive "CALV" |
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| Direction: server -> client |
| Parameters: None |
| Description: |
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| Keep connection alive. Sent by the server periodically to verify |
| that connections are still up and running. clients must reply in |
| kind on receipt. if the server gets an error sending the message or |
| does not receive a reply within a reasonable time then the server |
| disconnects the client. if the client doesn't receive these (or any |
| message) periodically then it should disconnect from the server. the |
| appropriate interval is defined by an option. |
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| - barrierCmdDKeyDown "DKDN" |
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| Direction: server -> client |
| Parameters: { int16_t keyid, int16_t modifier [,int16_t button] } |
| Description: |
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| Key pressed. |
| keyid = X11 key id |
| modified = modified mask |
| button = X11 Xkb keycode (optional) |
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| - barrierCmdDKeyRepeat "DKRP" |
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| Direction: server -> client |
| Parameters: { int16_t keyid, int16_t modifier, int16_t repeat [,int16_t button] } |
| Description: |
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| Key auto-repeat. |
| keyid = X11 key id |
| modified = modified mask |
| repeat = number of repeats |
| button = X11 Xkb keycode (optional) |
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| - barrierCmdDKeyUp "DKUP" |
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| Direction: server -> client |
| Parameters: { int16_t keyid, int16_t modifier [,int16_t button] } |
| Description: |
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| Key released. |
| keyid = X11 key id |
| modified = modified mask |
| button = X11 Xkb keycode (optional) |
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| - barrierCmdDMouseDown "DMDN" |
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| Direction: server -> client |
| Parameters: { int8_t button } |
| Description: |
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| Mouse button pressed. |
| button = button id |
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| - barrierCmdDMouseUp "DMUP" |
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| Direction: server -> client |
| Parameters: { int8_t button } |
| Description: |
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| Mouse button release. |
| button = button id |
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| - barrierCmdDMouseMove "DMMV" |
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| Direction: server -> client |
| Parameters: { int16_t x, int16_t y } |
| Description: |
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| Absolute mouse moved. |
| x,y = absolute screen coordinates |
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| - barrierCmdDMouseRelMove "DMRM" |
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| Direction: server -> client |
| Parameters: { int16_t x, int16_t y } |
| Description: |
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| Relative mouse moved. |
| x,y = r relative screen coordinates |
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| - barrierCmdDMouseWheel "DMWM" |
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| Direction: server -> client |
| Parameters: { int16_t x , int16_t y } or { int16_t y } |
| Description: |
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| Mouse scroll. The delta should be +120 for one tick forward (away |
| from the user) or right and -120 for one tick backward (toward the |
| user) or left. |
| x = x delta |
| y = y delta |
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| - barrierCmdDClipboard "DCLP" |
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| Direction: server -> client |
| Parameters: { int8_t id, int32_t seq, int8_t mark, char *data } |
| Description: |
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| Clipboard data. |
| id = clipboard id |
| seq = sequence number. The sequence number is 0 when sent by the |
| server. Client screens should use the/ sequence number from |
| the most recent barrierCmdCEnter. |
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| - barrierCmdDSetOptions "DSOP" |
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| Direction: server -> client |
| Parameters: { int32 t nb, { int32_t id, int32_t val }[] } |
| Description: |
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| Set options. Client should set the given option/value pairs. |
| nb = numbers of { id, val } entries |
| id = option id |
| val = option new value |
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| - barrierCmdDFileTransfer "DFTR" |
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| Direction: server -> client |
| Parameters: { int8_t mark, char *content } |
| Description: |
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| Transfer file data. |
| mark = 0 means the content followed is the file size |
| 1 means the content followed is the chunk data |
| 2 means the file transfer is finished |
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| - barrierCmdDDragInfo "DDRG" int16_t char * |
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| Direction: server -> client |
| Parameters: { int16_t nb, char *content } |
| Description: |
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| Drag information. |
| nb = number of dragging objects |
| content = object's directory |
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| - barrierCmdQInfo "QINF" |
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| Direction: server -> client |
| Parameters: None |
| Description: |
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| Query screen info |
| Client should reply with a barrierCmdDInfo |
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| - barrierCmdEIncompatible "EICV" |
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| Direction: server -> client |
| Parameters: { int16_t nb, major *minor } |
| Description: |
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| Incompatible version. |
| major = major version |
| minor = minor version |
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| - barrierCmdEBusy "EBSY" |
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| Direction: server -> client |
| Parameters: None |
| Description: |
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| Name provided when connecting is already in use. |
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| - barrierCmdEUnknown "EUNK" |
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| Direction: server -> client |
| Parameters: None |
| Description: |
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| Unknown client. Name provided when connecting is not in primary's |
| screen configuration map. |
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| - barrierCmdEBad "EBAD" |
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| Direction: server -> client |
| Parameters: None |
| Description: |
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| Protocol violation. Server should disconnect after sending this |
| message. |
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| * TO DO |
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| - Enable SSL |
| - Manage SetOptions/ResetOptions commands |
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