1 /* 2 * Xenbus code for netif backend 3 * 4 * Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au> 5 * Copyright (C) 2005 XenSource Ltd 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 22 #include "common.h" 23 24 struct backend_info { 25 struct xenbus_device *dev; 26 struct xenvif *vif; 27 28 /* This is the state that will be reflected in xenstore when any 29 * active hotplug script completes. 30 */ 31 enum xenbus_state state; 32 33 enum xenbus_state frontend_state; 34 struct xenbus_watch hotplug_status_watch; 35 u8 have_hotplug_status_watch:1; 36 }; 37 38 static int connect_rings(struct backend_info *); 39 static void connect(struct backend_info *); 40 static void backend_create_xenvif(struct backend_info *be); 41 static void unregister_hotplug_status_watch(struct backend_info *be); 42 43 static int netback_remove(struct xenbus_device *dev) 44 { 45 struct backend_info *be = dev_get_drvdata(&dev->dev); 46 47 unregister_hotplug_status_watch(be); 48 if (be->vif) { 49 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); 50 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); 51 xenvif_free(be->vif); 52 be->vif = NULL; 53 } 54 kfree(be); 55 dev_set_drvdata(&dev->dev, NULL); 56 return 0; 57 } 58 59 60 /** 61 * Entry point to this code when a new device is created. Allocate the basic 62 * structures and switch to InitWait. 63 */ 64 static int netback_probe(struct xenbus_device *dev, 65 const struct xenbus_device_id *id) 66 { 67 const char *message; 68 struct xenbus_transaction xbt; 69 int err; 70 int sg; 71 struct backend_info *be = kzalloc(sizeof(struct backend_info), 72 GFP_KERNEL); 73 if (!be) { 74 xenbus_dev_fatal(dev, -ENOMEM, 75 "allocating backend structure"); 76 return -ENOMEM; 77 } 78 79 be->dev = dev; 80 dev_set_drvdata(&dev->dev, be); 81 82 sg = 1; 83 84 do { 85 err = xenbus_transaction_start(&xbt); 86 if (err) { 87 xenbus_dev_fatal(dev, err, "starting transaction"); 88 goto fail; 89 } 90 91 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg); 92 if (err) { 93 message = "writing feature-sg"; 94 goto abort_transaction; 95 } 96 97 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", 98 "%d", sg); 99 if (err) { 100 message = "writing feature-gso-tcpv4"; 101 goto abort_transaction; 102 } 103 104 /* We support rx-copy path. */ 105 err = xenbus_printf(xbt, dev->nodename, 106 "feature-rx-copy", "%d", 1); 107 if (err) { 108 message = "writing feature-rx-copy"; 109 goto abort_transaction; 110 } 111 112 /* 113 * We don't support rx-flip path (except old guests who don't 114 * grok this feature flag). 115 */ 116 err = xenbus_printf(xbt, dev->nodename, 117 "feature-rx-flip", "%d", 0); 118 if (err) { 119 message = "writing feature-rx-flip"; 120 goto abort_transaction; 121 } 122 123 err = xenbus_transaction_end(xbt, 0); 124 } while (err == -EAGAIN); 125 126 if (err) { 127 xenbus_dev_fatal(dev, err, "completing transaction"); 128 goto fail; 129 } 130 131 /* 132 * Split event channels support, this is optional so it is not 133 * put inside the above loop. 134 */ 135 err = xenbus_printf(XBT_NIL, dev->nodename, 136 "feature-split-event-channels", 137 "%u", separate_tx_rx_irq); 138 if (err) 139 pr_debug("Error writing feature-split-event-channels\n"); 140 141 err = xenbus_switch_state(dev, XenbusStateInitWait); 142 if (err) 143 goto fail; 144 145 be->state = XenbusStateInitWait; 146 147 /* This kicks hotplug scripts, so do it immediately. */ 148 backend_create_xenvif(be); 149 150 return 0; 151 152 abort_transaction: 153 xenbus_transaction_end(xbt, 1); 154 xenbus_dev_fatal(dev, err, "%s", message); 155 fail: 156 pr_debug("failed\n"); 157 netback_remove(dev); 158 return err; 159 } 160 161 162 /* 163 * Handle the creation of the hotplug script environment. We add the script 164 * and vif variables to the environment, for the benefit of the vif-* hotplug 165 * scripts. 166 */ 167 static int netback_uevent(struct xenbus_device *xdev, 168 struct kobj_uevent_env *env) 169 { 170 struct backend_info *be = dev_get_drvdata(&xdev->dev); 171 char *val; 172 173 val = xenbus_read(XBT_NIL, xdev->nodename, "script", NULL); 174 if (IS_ERR(val)) { 175 int err = PTR_ERR(val); 176 xenbus_dev_fatal(xdev, err, "reading script"); 177 return err; 178 } else { 179 if (add_uevent_var(env, "script=%s", val)) { 180 kfree(val); 181 return -ENOMEM; 182 } 183 kfree(val); 184 } 185 186 if (!be || !be->vif) 187 return 0; 188 189 return add_uevent_var(env, "vif=%s", be->vif->dev->name); 190 } 191 192 193 static void backend_create_xenvif(struct backend_info *be) 194 { 195 int err; 196 long handle; 197 struct xenbus_device *dev = be->dev; 198 199 if (be->vif != NULL) 200 return; 201 202 err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle); 203 if (err != 1) { 204 xenbus_dev_fatal(dev, err, "reading handle"); 205 return; 206 } 207 208 be->vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle); 209 if (IS_ERR(be->vif)) { 210 err = PTR_ERR(be->vif); 211 be->vif = NULL; 212 xenbus_dev_fatal(dev, err, "creating interface"); 213 return; 214 } 215 216 kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE); 217 } 218 219 static void backend_disconnect(struct backend_info *be) 220 { 221 if (be->vif) 222 xenvif_disconnect(be->vif); 223 } 224 225 static void backend_connect(struct backend_info *be) 226 { 227 if (be->vif) 228 connect(be); 229 } 230 231 static inline void backend_switch_state(struct backend_info *be, 232 enum xenbus_state state) 233 { 234 struct xenbus_device *dev = be->dev; 235 236 pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state)); 237 be->state = state; 238 239 /* If we are waiting for a hotplug script then defer the 240 * actual xenbus state change. 241 */ 242 if (!be->have_hotplug_status_watch) 243 xenbus_switch_state(dev, state); 244 } 245 246 /* Handle backend state transitions: 247 * 248 * The backend state starts in InitWait and the following transitions are 249 * allowed. 250 * 251 * InitWait -> Connected 252 * 253 * ^ \ | 254 * | \ | 255 * | \ | 256 * | \ | 257 * | \ | 258 * | \ | 259 * | V V 260 * 261 * Closed <-> Closing 262 * 263 * The state argument specifies the eventual state of the backend and the 264 * function transitions to that state via the shortest path. 265 */ 266 static void set_backend_state(struct backend_info *be, 267 enum xenbus_state state) 268 { 269 while (be->state != state) { 270 switch (be->state) { 271 case XenbusStateClosed: 272 switch (state) { 273 case XenbusStateInitWait: 274 case XenbusStateConnected: 275 pr_info("%s: prepare for reconnect\n", 276 be->dev->nodename); 277 backend_switch_state(be, XenbusStateInitWait); 278 break; 279 case XenbusStateClosing: 280 backend_switch_state(be, XenbusStateClosing); 281 break; 282 default: 283 BUG(); 284 } 285 break; 286 case XenbusStateInitWait: 287 switch (state) { 288 case XenbusStateConnected: 289 backend_connect(be); 290 backend_switch_state(be, XenbusStateConnected); 291 break; 292 case XenbusStateClosing: 293 case XenbusStateClosed: 294 backend_switch_state(be, XenbusStateClosing); 295 break; 296 default: 297 BUG(); 298 } 299 break; 300 case XenbusStateConnected: 301 switch (state) { 302 case XenbusStateInitWait: 303 case XenbusStateClosing: 304 case XenbusStateClosed: 305 backend_disconnect(be); 306 backend_switch_state(be, XenbusStateClosing); 307 break; 308 default: 309 BUG(); 310 } 311 break; 312 case XenbusStateClosing: 313 switch (state) { 314 case XenbusStateInitWait: 315 case XenbusStateConnected: 316 case XenbusStateClosed: 317 backend_switch_state(be, XenbusStateClosed); 318 break; 319 default: 320 BUG(); 321 } 322 break; 323 default: 324 BUG(); 325 } 326 } 327 } 328 329 /** 330 * Callback received when the frontend's state changes. 331 */ 332 static void frontend_changed(struct xenbus_device *dev, 333 enum xenbus_state frontend_state) 334 { 335 struct backend_info *be = dev_get_drvdata(&dev->dev); 336 337 pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state)); 338 339 be->frontend_state = frontend_state; 340 341 switch (frontend_state) { 342 case XenbusStateInitialising: 343 set_backend_state(be, XenbusStateInitWait); 344 break; 345 346 case XenbusStateInitialised: 347 break; 348 349 case XenbusStateConnected: 350 set_backend_state(be, XenbusStateConnected); 351 break; 352 353 case XenbusStateClosing: 354 set_backend_state(be, XenbusStateClosing); 355 break; 356 357 case XenbusStateClosed: 358 set_backend_state(be, XenbusStateClosed); 359 if (xenbus_dev_is_online(dev)) 360 break; 361 /* fall through if not online */ 362 case XenbusStateUnknown: 363 set_backend_state(be, XenbusStateClosed); 364 device_unregister(&dev->dev); 365 break; 366 367 default: 368 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 369 frontend_state); 370 break; 371 } 372 } 373 374 375 static void xen_net_read_rate(struct xenbus_device *dev, 376 unsigned long *bytes, unsigned long *usec) 377 { 378 char *s, *e; 379 unsigned long b, u; 380 char *ratestr; 381 382 /* Default to unlimited bandwidth. */ 383 *bytes = ~0UL; 384 *usec = 0; 385 386 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL); 387 if (IS_ERR(ratestr)) 388 return; 389 390 s = ratestr; 391 b = simple_strtoul(s, &e, 10); 392 if ((s == e) || (*e != ',')) 393 goto fail; 394 395 s = e + 1; 396 u = simple_strtoul(s, &e, 10); 397 if ((s == e) || (*e != '\0')) 398 goto fail; 399 400 *bytes = b; 401 *usec = u; 402 403 kfree(ratestr); 404 return; 405 406 fail: 407 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n"); 408 kfree(ratestr); 409 } 410 411 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) 412 { 413 char *s, *e, *macstr; 414 int i; 415 416 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL); 417 if (IS_ERR(macstr)) 418 return PTR_ERR(macstr); 419 420 for (i = 0; i < ETH_ALEN; i++) { 421 mac[i] = simple_strtoul(s, &e, 16); 422 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) { 423 kfree(macstr); 424 return -ENOENT; 425 } 426 s = e+1; 427 } 428 429 kfree(macstr); 430 return 0; 431 } 432 433 static void unregister_hotplug_status_watch(struct backend_info *be) 434 { 435 if (be->have_hotplug_status_watch) { 436 unregister_xenbus_watch(&be->hotplug_status_watch); 437 kfree(be->hotplug_status_watch.node); 438 } 439 be->have_hotplug_status_watch = 0; 440 } 441 442 static void hotplug_status_changed(struct xenbus_watch *watch, 443 const char **vec, 444 unsigned int vec_size) 445 { 446 struct backend_info *be = container_of(watch, 447 struct backend_info, 448 hotplug_status_watch); 449 char *str; 450 unsigned int len; 451 452 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len); 453 if (IS_ERR(str)) 454 return; 455 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) { 456 /* Complete any pending state change */ 457 xenbus_switch_state(be->dev, be->state); 458 459 /* Not interested in this watch anymore. */ 460 unregister_hotplug_status_watch(be); 461 } 462 kfree(str); 463 } 464 465 static void connect(struct backend_info *be) 466 { 467 int err; 468 struct xenbus_device *dev = be->dev; 469 470 err = connect_rings(be); 471 if (err) 472 return; 473 474 err = xen_net_read_mac(dev, be->vif->fe_dev_addr); 475 if (err) { 476 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename); 477 return; 478 } 479 480 xen_net_read_rate(dev, &be->vif->credit_bytes, 481 &be->vif->credit_usec); 482 be->vif->remaining_credit = be->vif->credit_bytes; 483 484 unregister_hotplug_status_watch(be); 485 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, 486 hotplug_status_changed, 487 "%s/%s", dev->nodename, "hotplug-status"); 488 if (!err) 489 be->have_hotplug_status_watch = 1; 490 491 netif_wake_queue(be->vif->dev); 492 } 493 494 495 static int connect_rings(struct backend_info *be) 496 { 497 struct xenvif *vif = be->vif; 498 struct xenbus_device *dev = be->dev; 499 unsigned long tx_ring_ref, rx_ring_ref; 500 unsigned int tx_evtchn, rx_evtchn, rx_copy; 501 int err; 502 int val; 503 504 err = xenbus_gather(XBT_NIL, dev->otherend, 505 "tx-ring-ref", "%lu", &tx_ring_ref, 506 "rx-ring-ref", "%lu", &rx_ring_ref, NULL); 507 if (err) { 508 xenbus_dev_fatal(dev, err, 509 "reading %s/ring-ref", 510 dev->otherend); 511 return err; 512 } 513 514 /* Try split event channels first, then single event channel. */ 515 err = xenbus_gather(XBT_NIL, dev->otherend, 516 "event-channel-tx", "%u", &tx_evtchn, 517 "event-channel-rx", "%u", &rx_evtchn, NULL); 518 if (err < 0) { 519 err = xenbus_scanf(XBT_NIL, dev->otherend, 520 "event-channel", "%u", &tx_evtchn); 521 if (err < 0) { 522 xenbus_dev_fatal(dev, err, 523 "reading %s/event-channel(-tx/rx)", 524 dev->otherend); 525 return err; 526 } 527 rx_evtchn = tx_evtchn; 528 } 529 530 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u", 531 &rx_copy); 532 if (err == -ENOENT) { 533 err = 0; 534 rx_copy = 0; 535 } 536 if (err < 0) { 537 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy", 538 dev->otherend); 539 return err; 540 } 541 if (!rx_copy) 542 return -EOPNOTSUPP; 543 544 if (vif->dev->tx_queue_len != 0) { 545 if (xenbus_scanf(XBT_NIL, dev->otherend, 546 "feature-rx-notify", "%d", &val) < 0) 547 val = 0; 548 if (val) 549 vif->can_queue = 1; 550 else 551 /* Must be non-zero for pfifo_fast to work. */ 552 vif->dev->tx_queue_len = 1; 553 } 554 555 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg", 556 "%d", &val) < 0) 557 val = 0; 558 vif->can_sg = !!val; 559 560 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4", 561 "%d", &val) < 0) 562 val = 0; 563 vif->gso = !!val; 564 565 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix", 566 "%d", &val) < 0) 567 val = 0; 568 vif->gso_prefix = !!val; 569 570 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload", 571 "%d", &val) < 0) 572 val = 0; 573 vif->csum = !val; 574 575 /* Map the shared frame, irq etc. */ 576 err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, 577 tx_evtchn, rx_evtchn); 578 if (err) { 579 xenbus_dev_fatal(dev, err, 580 "mapping shared-frames %lu/%lu port tx %u rx %u", 581 tx_ring_ref, rx_ring_ref, 582 tx_evtchn, rx_evtchn); 583 return err; 584 } 585 return 0; 586 } 587 588 589 /* ** Driver Registration ** */ 590 591 592 static const struct xenbus_device_id netback_ids[] = { 593 { "vif" }, 594 { "" } 595 }; 596 597 598 static DEFINE_XENBUS_DRIVER(netback, , 599 .probe = netback_probe, 600 .remove = netback_remove, 601 .uevent = netback_uevent, 602 .otherend_changed = frontend_changed, 603 ); 604 605 int xenvif_xenbus_init(void) 606 { 607 return xenbus_register_backend(&netback_driver); 608 } 609 610 void xenvif_xenbus_fini(void) 611 { 612 return xenbus_unregister_driver(&netback_driver); 613 } 614