| 1 | Barrier client protocol |
| 2 | ======================= |
| 3 | |
| 4 | QEMU's ``input-barrier`` device implements the client end of |
| 5 | the KVM (Keyboard-Video-Mouse) software |
| 6 | `Barrier <https://github.com/debauchee/barrier>`__. |
| 7 | |
| 8 | This document briefly describes the protocol as we implement it. |
| 9 | |
| 10 | Message format |
| 11 | -------------- |
| 12 | |
| 13 | Message format between the server and client is in two parts: |
| 14 | |
| 15 | #. the payload length, a 32bit integer in network endianness |
| 16 | #. the payload |
| 17 | |
| 18 | The payload starts with a 4byte string (without NUL) which is the |
| 19 | command. The first command between the server and the client |
| 20 | is the only command not encoded on 4 bytes ("Barrier"). |
| 21 | The remaining part of the payload is decoded according to the command. |
| 22 | |
| 23 | Protocol Description |
| 24 | -------------------- |
| 25 | |
| 26 | This comes from ``barrier/src/lib/barrier/protocol_types.h``. |
| 27 | |
| 28 | barrierCmdHello "Barrier" |
| 29 | ^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 30 | |
| 31 | Direction: |
| 32 | server -> client |
| 33 | Parameters: |
| 34 | ``{ int16_t minor, int16_t major }`` |
| 35 | Description: |
| 36 | Say hello to client |
| 37 | |
| 38 | ``minor`` = protocol major version number supported by server |
| 39 | |
| 40 | ``major`` = protocol minor version number supported by server |
| 41 | |
| 42 | barrierCmdHelloBack "Barrier" |
| 43 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 44 | |
| 45 | Direction: |
| 46 | client ->server |
| 47 | Parameters: |
| 48 | ``{ int16_t minor, int16_t major, char *name}`` |
| 49 | Description: |
| 50 | Respond to hello from server |
| 51 | |
| 52 | ``minor`` = protocol major version number supported by client |
| 53 | |
| 54 | ``major`` = protocol minor version number supported by client |
| 55 | |
| 56 | ``name`` = client name |
| 57 | |
| 58 | barrierCmdDInfo "DINF" |
| 59 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 60 | |
| 61 | Direction: |
| 62 | client ->server |
| 63 | Parameters: |
| 64 | ``{ int16_t x_origin, int16_t y_origin, int16_t width, int16_t height, int16_t x, int16_t y}`` |
| 65 | Description: |
| 66 | The client screen must send this message in response to the |
| 67 | barrierCmdQInfo message. It must also send this message when the |
| 68 | screen's resolution changes. In this case, the client screen should |
| 69 | ignore any barrierCmdDMouseMove messages until it receives a |
| 70 | barrierCmdCInfoAck in order to prevent attempts to move the mouse off |
| 71 | the new screen area. |
| 72 | |
| 73 | barrierCmdCNoop "CNOP" |
| 74 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 75 | |
| 76 | Direction: |
| 77 | client -> server |
| 78 | Parameters: |
| 79 | None |
| 80 | Description: |
| 81 | No operation |
| 82 | |
| 83 | barrierCmdCClose "CBYE" |
| 84 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 85 | |
| 86 | Direction: |
| 87 | server -> client |
| 88 | Parameters: |
| 89 | None |
| 90 | Description: |
| 91 | Close connection |
| 92 | |
| 93 | barrierCmdCEnter "CINN" |
| 94 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 95 | |
| 96 | Direction: |
| 97 | server -> client |
| 98 | Parameters: |
| 99 | ``{ int16_t x, int16_t y, int32_t seq, int16_t modifier }`` |
| 100 | Description: |
| 101 | Enter screen. |
| 102 | |
| 103 | ``x``, ``y`` = entering screen absolute coordinates |
| 104 | |
| 105 | ``seq`` = sequence number, which is used to order messages between |
| 106 | screens. the secondary screen must return this number |
| 107 | with some messages |
| 108 | |
| 109 | ``modifier`` = modifier key mask. this will have bits set for each |
| 110 | toggle modifier key that is activated on entry to the |
| 111 | screen. the secondary screen should adjust its toggle |
| 112 | modifiers to reflect that state. |
| 113 | |
| 114 | barrierCmdCLeave "COUT" |
| 115 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 116 | |
| 117 | Direction: |
| 118 | server -> client |
| 119 | Parameters: |
| 120 | None |
| 121 | Description: |
| 122 | Leaving screen. the secondary screen should send clipboard data in |
| 123 | response to this message for those clipboards that it has grabbed |
| 124 | (i.e. has sent a barrierCmdCClipboard for and has not received a |
| 125 | barrierCmdCClipboard for with a greater sequence number) and that |
| 126 | were grabbed or have changed since the last leave. |
| 127 | |
| 128 | barrierCmdCClipboard "CCLP" |
| 129 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 130 | |
| 131 | Direction: |
| 132 | server -> client |
| 133 | Parameters: |
| 134 | ``{ int8_t id, int32_t seq }`` |
| 135 | Description: |
| 136 | Grab clipboard. Sent by screen when some other app on that screen |
| 137 | grabs a clipboard. |
| 138 | |
| 139 | ``id`` = the clipboard identifier |
| 140 | |
| 141 | ``seq`` = sequence number. Client must use the sequence number passed in |
| 142 | the most recent barrierCmdCEnter. the server always sends 0. |
| 143 | |
| 144 | barrierCmdCScreenSaver "CSEC" |
| 145 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 146 | |
| 147 | Direction: |
| 148 | server -> client |
| 149 | Parameters: |
| 150 | ``{ int8_t started }`` |
| 151 | Description: |
| 152 | Screensaver change. |
| 153 | |
| 154 | ``started`` = Screensaver on primary has started (1) or closed (0) |
| 155 | |
| 156 | barrierCmdCResetOptions "CROP" |
| 157 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 158 | |
| 159 | Direction: |
| 160 | server -> client |
| 161 | Parameters: |
| 162 | None |
| 163 | Description: |
| 164 | Reset options. Client should reset all of its options to their |
| 165 | defaults. |
| 166 | |
| 167 | barrierCmdCInfoAck "CIAK" |
| 168 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 169 | |
| 170 | Direction: |
| 171 | server -> client |
| 172 | Parameters: |
| 173 | None |
| 174 | Description: |
| 175 | Resolution change acknowledgment. Sent by server in response to a |
| 176 | client screen's barrierCmdDInfo. This is sent for every |
| 177 | barrierCmdDInfo, whether or not the server had sent a barrierCmdQInfo. |
| 178 | |
| 179 | barrierCmdCKeepAlive "CALV" |
| 180 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 181 | |
| 182 | Direction: |
| 183 | server -> client |
| 184 | Parameters: |
| 185 | None |
| 186 | Description: |
| 187 | Keep connection alive. Sent by the server periodically to verify |
| 188 | that connections are still up and running. clients must reply in |
| 189 | kind on receipt. if the server gets an error sending the message or |
| 190 | does not receive a reply within a reasonable time then the server |
| 191 | disconnects the client. if the client doesn't receive these (or any |
| 192 | message) periodically then it should disconnect from the server. the |
| 193 | appropriate interval is defined by an option. |
| 194 | |
| 195 | barrierCmdDKeyDown "DKDN" |
| 196 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 197 | |
| 198 | Direction: |
| 199 | server -> client |
| 200 | Parameters: |
| 201 | ``{ int16_t keyid, int16_t modifier [,int16_t button] }`` |
| 202 | Description: |
| 203 | Key pressed. |
| 204 | |
| 205 | ``keyid`` = X11 key id |
| 206 | |
| 207 | ``modified`` = modified mask |
| 208 | |
| 209 | ``button`` = X11 Xkb keycode (optional) |
| 210 | |
| 211 | barrierCmdDKeyRepeat "DKRP" |
| 212 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 213 | |
| 214 | Direction: |
| 215 | server -> client |
| 216 | Parameters: |
| 217 | ``{ int16_t keyid, int16_t modifier, int16_t repeat [,int16_t button] }`` |
| 218 | Description: |
| 219 | Key auto-repeat. |
| 220 | |
| 221 | ``keyid`` = X11 key id |
| 222 | |
| 223 | ``modified`` = modified mask |
| 224 | |
| 225 | ``repeat`` = number of repeats |
| 226 | |
| 227 | ``button`` = X11 Xkb keycode (optional) |
| 228 | |
| 229 | barrierCmdDKeyUp "DKUP" |
| 230 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 231 | |
| 232 | Direction: |
| 233 | server -> client |
| 234 | Parameters: |
| 235 | ``{ int16_t keyid, int16_t modifier [,int16_t button] }`` |
| 236 | Description: |
| 237 | Key released. |
| 238 | |
| 239 | ``keyid`` = X11 key id |
| 240 | |
| 241 | ``modified`` = modified mask |
| 242 | |
| 243 | ``button`` = X11 Xkb keycode (optional) |
| 244 | |
| 245 | barrierCmdDMouseDown "DMDN" |
| 246 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 247 | |
| 248 | Direction: |
| 249 | server -> client |
| 250 | Parameters: |
| 251 | ``{ int8_t button }`` |
| 252 | Description: |
| 253 | Mouse button pressed. |
| 254 | |
| 255 | ``button`` = button id |
| 256 | |
| 257 | barrierCmdDMouseUp "DMUP" |
| 258 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 259 | |
| 260 | Direction: |
| 261 | server -> client |
| 262 | Parameters: |
| 263 | ``{ int8_t button }`` |
| 264 | Description: |
| 265 | Mouse button release. |
| 266 | |
| 267 | ``button`` = button id |
| 268 | |
| 269 | barrierCmdDMouseMove "DMMV" |
| 270 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 271 | |
| 272 | Direction: |
| 273 | server -> client |
| 274 | Parameters: |
| 275 | ``{ int16_t x, int16_t y }`` |
| 276 | Description: |
| 277 | Absolute mouse moved. |
| 278 | |
| 279 | ``x``, ``y`` = absolute screen coordinates |
| 280 | |
| 281 | barrierCmdDMouseRelMove "DMRM" |
| 282 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 283 | |
| 284 | Direction: |
| 285 | server -> client |
| 286 | Parameters: |
| 287 | ``{ int16_t x, int16_t y }`` |
| 288 | Description: |
| 289 | Relative mouse moved. |
| 290 | |
| 291 | ``x``, ``y`` = r relative screen coordinates |
| 292 | |
| 293 | barrierCmdDMouseWheel "DMWM" |
| 294 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 295 | |
| 296 | Direction: |
| 297 | server -> client |
| 298 | Parameters: |
| 299 | ``{ int16_t x , int16_t y }`` or ``{ int16_t y }`` |
| 300 | Description: |
| 301 | Mouse scroll. The delta should be +120 for one tick forward (away |
| 302 | from the user) or right and -120 for one tick backward (toward the |
| 303 | user) or left. |
| 304 | |
| 305 | ``x`` = x delta |
| 306 | |
| 307 | ``y`` = y delta |
| 308 | |
| 309 | barrierCmdDClipboard "DCLP" |
| 310 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 311 | |
| 312 | Direction: |
| 313 | server -> client |
| 314 | Parameters: |
| 315 | ``{ int8_t id, int32_t seq, int8_t mark, char *data }`` |
| 316 | Description: |
| 317 | Clipboard data. |
| 318 | |
| 319 | ``id`` = clipboard id |
| 320 | |
| 321 | ``seq`` = sequence number. The sequence number is 0 when sent by the |
| 322 | server. Client screens should use the/ sequence number from |
| 323 | the most recent barrierCmdCEnter. |
| 324 | |
| 325 | barrierCmdDSetOptions "DSOP" |
| 326 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 327 | |
| 328 | Direction: |
| 329 | server -> client |
| 330 | Parameters: |
| 331 | ``{ int32 t nb, { int32_t id, int32_t val }[] }`` |
| 332 | Description: |
| 333 | Set options. Client should set the given option/value pairs. |
| 334 | |
| 335 | ``nb`` = numbers of ``{ id, val }`` entries |
| 336 | |
| 337 | ``id`` = option id |
| 338 | |
| 339 | ``val`` = option new value |
| 340 | |
| 341 | barrierCmdDFileTransfer "DFTR" |
| 342 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 343 | |
| 344 | Direction: |
| 345 | server -> client |
| 346 | Parameters: |
| 347 | ``{ int8_t mark, char *content }`` |
| 348 | Description: |
| 349 | Transfer file data. |
| 350 | |
| 351 | * ``mark`` = 0 means the content followed is the file size |
| 352 | * 1 means the content followed is the chunk data |
| 353 | * 2 means the file transfer is finished |
| 354 | |
| 355 | barrierCmdDDragInfo "DDRG" |
| 356 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 357 | |
| 358 | Direction: |
| 359 | server -> client |
| 360 | Parameters: |
| 361 | ``{ int16_t nb, char *content }`` |
| 362 | Description: |
| 363 | Drag information. |
| 364 | |
| 365 | ``nb`` = number of dragging objects |
| 366 | |
| 367 | ``content`` = object's directory |
| 368 | |
| 369 | barrierCmdQInfo "QINF" |
| 370 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 371 | |
| 372 | Direction: |
| 373 | server -> client |
| 374 | Parameters: |
| 375 | None |
| 376 | Description: |
| 377 | Query screen info |
| 378 | |
| 379 | Client should reply with a barrierCmdDInfo |
| 380 | |
| 381 | barrierCmdEIncompatible "EICV" |
| 382 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 383 | |
| 384 | Direction: |
| 385 | server -> client |
| 386 | Parameters: |
| 387 | ``{ int16_t nb, major *minor }`` |
| 388 | Description: |
| 389 | Incompatible version. |
| 390 | |
| 391 | ``major`` = major version |
| 392 | |
| 393 | ``minor`` = minor version |
| 394 | |
| 395 | barrierCmdEBusy "EBSY" |
| 396 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 397 | |
| 398 | Direction: |
| 399 | server -> client |
| 400 | Parameters: |
| 401 | None |
| 402 | Description: |
| 403 | Name provided when connecting is already in use. |
| 404 | |
| 405 | barrierCmdEUnknown "EUNK" |
| 406 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 407 | |
| 408 | Direction: |
| 409 | server -> client |
| 410 | Parameters: |
| 411 | None |
| 412 | Description: |
| 413 | Unknown client. Name provided when connecting is not in primary's |
| 414 | screen configuration map. |
| 415 | |
| 416 | barrierCmdEBad "EBAD" |
| 417 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 418 | |
| 419 | Direction: |
| 420 | server -> client |
| 421 | Parameters: |
| 422 | None |
| 423 | Description: |
| 424 | Protocol violation. Server should disconnect after sending this |
| 425 | message. |
| 426 |