QEMU Barrier Client * About Barrier is a KVM (Keyboard-Video-Mouse) software forked from Symless's synergy 1.9 codebase. See https://github.com/debauchee/barrier * QEMU usage Generally, mouse and keyboard are grabbed through the QEMU video interface emulation. 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. This protocol is enabled by adding an input-barrier object to QEMU. Syntax: input-barrier,id=,name= [,server=][,port=] [,x-origin=][,y-origin=] [,width=][,height=] The object can be added on the QEMU command line, for instance with: ... -object input-barrier,id=barrier0,name=VM-1 ... where VM-1 is the name the display configured int the Barrier server on the host providing the mouse and the keyboard events. by default is "localhost", port is 24800, and are set to 0, and 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: (qemu) object_del barrier0 (qemu) object_add input-barrier,id=barrier0,name=VM-1 * Message format Message format between the server and client is in two parts: 1- the payload length is a 32bit integer in network endianness, 2- the payload 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. * Protocol Description (from barrier/src/lib/barrier/protocol_types.h) - barrierCmdHello "Barrier" Direction: server -> client Parameters: { int16_t minor, int16_t major } Description: Say hello to client minor = protocol major version number supported by server major = protocol minor version number supported by server - barrierCmdHelloBack "Barrier" Direction: client ->server Parameters: { int16_t minor, int16_t major, char *name} Description: Respond to hello from server minor = protocol major version number supported by client major = protocol minor version number supported by client name = client name - barrierCmdDInfo "DINF" 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. - barrierCmdCNoop "CNOP" Direction: client -> server Parameters: None Description: No operation - barrierCmdCClose "CBYE" Direction: server -> client Parameters: None Description: Close connection - barrierCmdCEnter "CINN" Direction: server -> client Parameters: { int16_t x, int16_t y, int32_t seq, int16_t modifier } Description: 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. - barrierCmdCLeave "COUT" Direction: server -> client Parameters: None Description: 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. - barrierCmdCClipboard "CCLP" Direction: server -> client Parameters: { int8_t id, int32_t seq } Description: 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. - barrierCmdCScreenSaver "CSEC" Direction: server -> client Parameters: { int8_t started } Description: Screensaver change. started = Screensaver on primary has started (1) or closed (0) - barrierCmdCResetOptions "CROP" Direction: server -> client Parameters: None Description: Reset options. Client should reset all of its options to their defaults. - barrierCmdCInfoAck "CIAK" Direction: server -> client Parameters: None Description: 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. - barrierCmdCKeepAlive "CALV" Direction: server -> client Parameters: None Description: 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. - barrierCmdDKeyDown "DKDN" Direction: server -> client Parameters: { int16_t keyid, int16_t modifier [,int16_t button] } Description: Key pressed. keyid = X11 key id modified = modified mask button = X11 Xkb keycode (optional) - barrierCmdDKeyRepeat "DKRP" Direction: server -> client Parameters: { int16_t keyid, int16_t modifier, int16_t repeat [,int16_t button] } Description: Key auto-repeat. keyid = X11 key id modified = modified mask repeat = number of repeats button = X11 Xkb keycode (optional) - barrierCmdDKeyUp "DKUP" Direction: server -> client Parameters: { int16_t keyid, int16_t modifier [,int16_t button] } Description: Key released. keyid = X11 key id modified = modified mask button = X11 Xkb keycode (optional) - barrierCmdDMouseDown "DMDN" Direction: server -> client Parameters: { int8_t button } Description: Mouse button pressed. button = button id - barrierCmdDMouseUp "DMUP" Direction: server -> client Parameters: { int8_t button } Description: Mouse button release. button = button id - barrierCmdDMouseMove "DMMV" Direction: server -> client Parameters: { int16_t x, int16_t y } Description: Absolute mouse moved. x,y = absolute screen coordinates - barrierCmdDMouseRelMove "DMRM" Direction: server -> client Parameters: { int16_t x, int16_t y } Description: Relative mouse moved. x,y = r relative screen coordinates - barrierCmdDMouseWheel "DMWM" Direction: server -> client Parameters: { int16_t x , int16_t y } or { int16_t y } Description: 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 - barrierCmdDClipboard "DCLP" Direction: server -> client Parameters: { int8_t id, int32_t seq, int8_t mark, char *data } Description: 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. - barrierCmdDSetOptions "DSOP" Direction: server -> client Parameters: { int32 t nb, { int32_t id, int32_t val }[] } Description: Set options. Client should set the given option/value pairs. nb = numbers of { id, val } entries id = option id val = option new value - barrierCmdDFileTransfer "DFTR" Direction: server -> client Parameters: { int8_t mark, char *content } Description: 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 - barrierCmdDDragInfo "DDRG" int16_t char * Direction: server -> client Parameters: { int16_t nb, char *content } Description: Drag information. nb = number of dragging objects content = object's directory - barrierCmdQInfo "QINF" Direction: server -> client Parameters: None Description: Query screen info Client should reply with a barrierCmdDInfo - barrierCmdEIncompatible "EICV" Direction: server -> client Parameters: { int16_t nb, major *minor } Description: Incompatible version. major = major version minor = minor version - barrierCmdEBusy "EBSY" Direction: server -> client Parameters: None Description: Name provided when connecting is already in use. - barrierCmdEUnknown "EUNK" Direction: server -> client Parameters: None Description: Unknown client. Name provided when connecting is not in primary's screen configuration map. - barrierCmdEBad "EBAD" Direction: server -> client Parameters: None Description: Protocol violation. Server should disconnect after sending this message. * TO DO - Enable SSL - Manage SetOptions/ResetOptions commands