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 static void set_backend_state(struct backend_info *be, 43 enum xenbus_state state); 44 45 static int netback_remove(struct xenbus_device *dev) 46 { 47 struct backend_info *be = dev_get_drvdata(&dev->dev); 48 49 set_backend_state(be, XenbusStateClosed); 50 51 unregister_hotplug_status_watch(be); 52 if (be->vif) { 53 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); 54 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); 55 xenvif_free(be->vif); 56 be->vif = NULL; 57 } 58 kfree(be); 59 dev_set_drvdata(&dev->dev, NULL); 60 return 0; 61 } 62 63 64 /** 65 * Entry point to this code when a new device is created. Allocate the basic 66 * structures and switch to InitWait. 67 */ 68 static int netback_probe(struct xenbus_device *dev, 69 const struct xenbus_device_id *id) 70 { 71 const char *message; 72 struct xenbus_transaction xbt; 73 int err; 74 int sg; 75 struct backend_info *be = kzalloc(sizeof(struct backend_info), 76 GFP_KERNEL); 77 if (!be) { 78 xenbus_dev_fatal(dev, -ENOMEM, 79 "allocating backend structure"); 80 return -ENOMEM; 81 } 82 83 be->dev = dev; 84 dev_set_drvdata(&dev->dev, be); 85 86 sg = 1; 87 88 do { 89 err = xenbus_transaction_start(&xbt); 90 if (err) { 91 xenbus_dev_fatal(dev, err, "starting transaction"); 92 goto fail; 93 } 94 95 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg); 96 if (err) { 97 message = "writing feature-sg"; 98 goto abort_transaction; 99 } 100 101 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", 102 "%d", sg); 103 if (err) { 104 message = "writing feature-gso-tcpv4"; 105 goto abort_transaction; 106 } 107 108 /* We support rx-copy path. */ 109 err = xenbus_printf(xbt, dev->nodename, 110 "feature-rx-copy", "%d", 1); 111 if (err) { 112 message = "writing feature-rx-copy"; 113 goto abort_transaction; 114 } 115 116 /* 117 * We don't support rx-flip path (except old guests who don't 118 * grok this feature flag). 119 */ 120 err = xenbus_printf(xbt, dev->nodename, 121 "feature-rx-flip", "%d", 0); 122 if (err) { 123 message = "writing feature-rx-flip"; 124 goto abort_transaction; 125 } 126 127 err = xenbus_transaction_end(xbt, 0); 128 } while (err == -EAGAIN); 129 130 if (err) { 131 xenbus_dev_fatal(dev, err, "completing transaction"); 132 goto fail; 133 } 134 135 /* 136 * Split event channels support, this is optional so it is not 137 * put inside the above loop. 138 */ 139 err = xenbus_printf(XBT_NIL, dev->nodename, 140 "feature-split-event-channels", 141 "%u", separate_tx_rx_irq); 142 if (err) 143 pr_debug("Error writing feature-split-event-channels\n"); 144 145 err = xenbus_switch_state(dev, XenbusStateInitWait); 146 if (err) 147 goto fail; 148 149 be->state = XenbusStateInitWait; 150 151 /* This kicks hotplug scripts, so do it immediately. */ 152 backend_create_xenvif(be); 153 154 return 0; 155 156 abort_transaction: 157 xenbus_transaction_end(xbt, 1); 158 xenbus_dev_fatal(dev, err, "%s", message); 159 fail: 160 pr_debug("failed\n"); 161 netback_remove(dev); 162 return err; 163 } 164 165 166 /* 167 * Handle the creation of the hotplug script environment. We add the script 168 * and vif variables to the environment, for the benefit of the vif-* hotplug 169 * scripts. 170 */ 171 static int netback_uevent(struct xenbus_device *xdev, 172 struct kobj_uevent_env *env) 173 { 174 struct backend_info *be = dev_get_drvdata(&xdev->dev); 175 char *val; 176 177 val = xenbus_read(XBT_NIL, xdev->nodename, "script", NULL); 178 if (IS_ERR(val)) { 179 int err = PTR_ERR(val); 180 xenbus_dev_fatal(xdev, err, "reading script"); 181 return err; 182 } else { 183 if (add_uevent_var(env, "script=%s", val)) { 184 kfree(val); 185 return -ENOMEM; 186 } 187 kfree(val); 188 } 189 190 if (!be || !be->vif) 191 return 0; 192 193 return add_uevent_var(env, "vif=%s", be->vif->dev->name); 194 } 195 196 197 static void backend_create_xenvif(struct backend_info *be) 198 { 199 int err; 200 long handle; 201 struct xenbus_device *dev = be->dev; 202 203 if (be->vif != NULL) 204 return; 205 206 err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle); 207 if (err != 1) { 208 xenbus_dev_fatal(dev, err, "reading handle"); 209 return; 210 } 211 212 be->vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle); 213 if (IS_ERR(be->vif)) { 214 err = PTR_ERR(be->vif); 215 be->vif = NULL; 216 xenbus_dev_fatal(dev, err, "creating interface"); 217 return; 218 } 219 220 kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE); 221 } 222 223 static void backend_disconnect(struct backend_info *be) 224 { 225 if (be->vif) 226 xenvif_disconnect(be->vif); 227 } 228 229 static void backend_connect(struct backend_info *be) 230 { 231 if (be->vif) 232 connect(be); 233 } 234 235 static inline void backend_switch_state(struct backend_info *be, 236 enum xenbus_state state) 237 { 238 struct xenbus_device *dev = be->dev; 239 240 pr_debug("%s -> %s\n", dev->nodename, xenbus_strstate(state)); 241 be->state = state; 242 243 /* If we are waiting for a hotplug script then defer the 244 * actual xenbus state change. 245 */ 246 if (!be->have_hotplug_status_watch) 247 xenbus_switch_state(dev, state); 248 } 249 250 /* Handle backend state transitions: 251 * 252 * The backend state starts in InitWait and the following transitions are 253 * allowed. 254 * 255 * InitWait -> Connected 256 * 257 * ^ \ | 258 * | \ | 259 * | \ | 260 * | \ | 261 * | \ | 262 * | \ | 263 * | V V 264 * 265 * Closed <-> Closing 266 * 267 * The state argument specifies the eventual state of the backend and the 268 * function transitions to that state via the shortest path. 269 */ 270 static void set_backend_state(struct backend_info *be, 271 enum xenbus_state state) 272 { 273 while (be->state != state) { 274 switch (be->state) { 275 case XenbusStateClosed: 276 switch (state) { 277 case XenbusStateInitWait: 278 case XenbusStateConnected: 279 pr_info("%s: prepare for reconnect\n", 280 be->dev->nodename); 281 backend_switch_state(be, XenbusStateInitWait); 282 break; 283 case XenbusStateClosing: 284 backend_switch_state(be, XenbusStateClosing); 285 break; 286 default: 287 BUG(); 288 } 289 break; 290 case XenbusStateInitWait: 291 switch (state) { 292 case XenbusStateConnected: 293 backend_connect(be); 294 backend_switch_state(be, XenbusStateConnected); 295 break; 296 case XenbusStateClosing: 297 case XenbusStateClosed: 298 backend_switch_state(be, XenbusStateClosing); 299 break; 300 default: 301 BUG(); 302 } 303 break; 304 case XenbusStateConnected: 305 switch (state) { 306 case XenbusStateInitWait: 307 case XenbusStateClosing: 308 case XenbusStateClosed: 309 backend_disconnect(be); 310 backend_switch_state(be, XenbusStateClosing); 311 break; 312 default: 313 BUG(); 314 } 315 break; 316 case XenbusStateClosing: 317 switch (state) { 318 case XenbusStateInitWait: 319 case XenbusStateConnected: 320 case XenbusStateClosed: 321 backend_switch_state(be, XenbusStateClosed); 322 break; 323 default: 324 BUG(); 325 } 326 break; 327 default: 328 BUG(); 329 } 330 } 331 } 332 333 /** 334 * Callback received when the frontend's state changes. 335 */ 336 static void frontend_changed(struct xenbus_device *dev, 337 enum xenbus_state frontend_state) 338 { 339 struct backend_info *be = dev_get_drvdata(&dev->dev); 340 341 pr_debug("%s -> %s\n", dev->otherend, xenbus_strstate(frontend_state)); 342 343 be->frontend_state = frontend_state; 344 345 switch (frontend_state) { 346 case XenbusStateInitialising: 347 set_backend_state(be, XenbusStateInitWait); 348 break; 349 350 case XenbusStateInitialised: 351 break; 352 353 case XenbusStateConnected: 354 set_backend_state(be, XenbusStateConnected); 355 break; 356 357 case XenbusStateClosing: 358 set_backend_state(be, XenbusStateClosing); 359 break; 360 361 case XenbusStateClosed: 362 set_backend_state(be, XenbusStateClosed); 363 if (xenbus_dev_is_online(dev)) 364 break; 365 /* fall through if not online */ 366 case XenbusStateUnknown: 367 set_backend_state(be, XenbusStateClosed); 368 device_unregister(&dev->dev); 369 break; 370 371 default: 372 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 373 frontend_state); 374 break; 375 } 376 } 377 378 379 static void xen_net_read_rate(struct xenbus_device *dev, 380 unsigned long *bytes, unsigned long *usec) 381 { 382 char *s, *e; 383 unsigned long b, u; 384 char *ratestr; 385 386 /* Default to unlimited bandwidth. */ 387 *bytes = ~0UL; 388 *usec = 0; 389 390 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL); 391 if (IS_ERR(ratestr)) 392 return; 393 394 s = ratestr; 395 b = simple_strtoul(s, &e, 10); 396 if ((s == e) || (*e != ',')) 397 goto fail; 398 399 s = e + 1; 400 u = simple_strtoul(s, &e, 10); 401 if ((s == e) || (*e != '\0')) 402 goto fail; 403 404 *bytes = b; 405 *usec = u; 406 407 kfree(ratestr); 408 return; 409 410 fail: 411 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n"); 412 kfree(ratestr); 413 } 414 415 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) 416 { 417 char *s, *e, *macstr; 418 int i; 419 420 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL); 421 if (IS_ERR(macstr)) 422 return PTR_ERR(macstr); 423 424 for (i = 0; i < ETH_ALEN; i++) { 425 mac[i] = simple_strtoul(s, &e, 16); 426 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) { 427 kfree(macstr); 428 return -ENOENT; 429 } 430 s = e+1; 431 } 432 433 kfree(macstr); 434 return 0; 435 } 436 437 static void unregister_hotplug_status_watch(struct backend_info *be) 438 { 439 if (be->have_hotplug_status_watch) { 440 unregister_xenbus_watch(&be->hotplug_status_watch); 441 kfree(be->hotplug_status_watch.node); 442 } 443 be->have_hotplug_status_watch = 0; 444 } 445 446 static void hotplug_status_changed(struct xenbus_watch *watch, 447 const char **vec, 448 unsigned int vec_size) 449 { 450 struct backend_info *be = container_of(watch, 451 struct backend_info, 452 hotplug_status_watch); 453 char *str; 454 unsigned int len; 455 456 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len); 457 if (IS_ERR(str)) 458 return; 459 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) { 460 /* Complete any pending state change */ 461 xenbus_switch_state(be->dev, be->state); 462 463 /* Not interested in this watch anymore. */ 464 unregister_hotplug_status_watch(be); 465 } 466 kfree(str); 467 } 468 469 static void connect(struct backend_info *be) 470 { 471 int err; 472 struct xenbus_device *dev = be->dev; 473 474 err = connect_rings(be); 475 if (err) 476 return; 477 478 err = xen_net_read_mac(dev, be->vif->fe_dev_addr); 479 if (err) { 480 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename); 481 return; 482 } 483 484 xen_net_read_rate(dev, &be->vif->credit_bytes, 485 &be->vif->credit_usec); 486 be->vif->remaining_credit = be->vif->credit_bytes; 487 488 unregister_hotplug_status_watch(be); 489 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, 490 hotplug_status_changed, 491 "%s/%s", dev->nodename, "hotplug-status"); 492 if (!err) 493 be->have_hotplug_status_watch = 1; 494 495 netif_wake_queue(be->vif->dev); 496 } 497 498 499 static int connect_rings(struct backend_info *be) 500 { 501 struct xenvif *vif = be->vif; 502 struct xenbus_device *dev = be->dev; 503 unsigned long tx_ring_ref, rx_ring_ref; 504 unsigned int tx_evtchn, rx_evtchn, rx_copy; 505 int err; 506 int val; 507 508 err = xenbus_gather(XBT_NIL, dev->otherend, 509 "tx-ring-ref", "%lu", &tx_ring_ref, 510 "rx-ring-ref", "%lu", &rx_ring_ref, NULL); 511 if (err) { 512 xenbus_dev_fatal(dev, err, 513 "reading %s/ring-ref", 514 dev->otherend); 515 return err; 516 } 517 518 /* Try split event channels first, then single event channel. */ 519 err = xenbus_gather(XBT_NIL, dev->otherend, 520 "event-channel-tx", "%u", &tx_evtchn, 521 "event-channel-rx", "%u", &rx_evtchn, NULL); 522 if (err < 0) { 523 err = xenbus_scanf(XBT_NIL, dev->otherend, 524 "event-channel", "%u", &tx_evtchn); 525 if (err < 0) { 526 xenbus_dev_fatal(dev, err, 527 "reading %s/event-channel(-tx/rx)", 528 dev->otherend); 529 return err; 530 } 531 rx_evtchn = tx_evtchn; 532 } 533 534 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u", 535 &rx_copy); 536 if (err == -ENOENT) { 537 err = 0; 538 rx_copy = 0; 539 } 540 if (err < 0) { 541 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy", 542 dev->otherend); 543 return err; 544 } 545 if (!rx_copy) 546 return -EOPNOTSUPP; 547 548 if (vif->dev->tx_queue_len != 0) { 549 if (xenbus_scanf(XBT_NIL, dev->otherend, 550 "feature-rx-notify", "%d", &val) < 0) 551 val = 0; 552 if (val) 553 vif->can_queue = 1; 554 else 555 /* Must be non-zero for pfifo_fast to work. */ 556 vif->dev->tx_queue_len = 1; 557 } 558 559 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg", 560 "%d", &val) < 0) 561 val = 0; 562 vif->can_sg = !!val; 563 564 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4", 565 "%d", &val) < 0) 566 val = 0; 567 vif->gso = !!val; 568 569 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix", 570 "%d", &val) < 0) 571 val = 0; 572 vif->gso_prefix = !!val; 573 574 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload", 575 "%d", &val) < 0) 576 val = 0; 577 vif->ip_csum = !val; 578 579 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-ipv6-csum-offload", 580 "%d", &val) < 0) 581 val = 0; 582 vif->ipv6_csum = !!val; 583 584 /* Map the shared frame, irq etc. */ 585 err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, 586 tx_evtchn, rx_evtchn); 587 if (err) { 588 xenbus_dev_fatal(dev, err, 589 "mapping shared-frames %lu/%lu port tx %u rx %u", 590 tx_ring_ref, rx_ring_ref, 591 tx_evtchn, rx_evtchn); 592 return err; 593 } 594 return 0; 595 } 596 597 598 /* ** Driver Registration ** */ 599 600 601 static const struct xenbus_device_id netback_ids[] = { 602 { "vif" }, 603 { "" } 604 }; 605 606 607 static DEFINE_XENBUS_DRIVER(netback, , 608 .probe = netback_probe, 609 .remove = netback_remove, 610 .uevent = netback_uevent, 611 .otherend_changed = frontend_changed, 612 ); 613 614 int xenvif_xenbus_init(void) 615 { 616 return xenbus_register_backend(&netback_driver); 617 } 618 619 void xenvif_xenbus_fini(void) 620 { 621 return xenbus_unregister_driver(&netback_driver); 622 } 623