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 enum xenbus_state frontend_state; 28 struct xenbus_watch hotplug_status_watch; 29 u8 have_hotplug_status_watch:1; 30 }; 31 32 static int connect_rings(struct backend_info *); 33 static void connect(struct backend_info *); 34 static void backend_create_xenvif(struct backend_info *be); 35 static void unregister_hotplug_status_watch(struct backend_info *be); 36 37 static int netback_remove(struct xenbus_device *dev) 38 { 39 struct backend_info *be = dev_get_drvdata(&dev->dev); 40 41 unregister_hotplug_status_watch(be); 42 if (be->vif) { 43 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); 44 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); 45 xenvif_free(be->vif); 46 be->vif = NULL; 47 } 48 kfree(be); 49 dev_set_drvdata(&dev->dev, NULL); 50 return 0; 51 } 52 53 54 /** 55 * Entry point to this code when a new device is created. Allocate the basic 56 * structures and switch to InitWait. 57 */ 58 static int netback_probe(struct xenbus_device *dev, 59 const struct xenbus_device_id *id) 60 { 61 const char *message; 62 struct xenbus_transaction xbt; 63 int err; 64 int sg; 65 struct backend_info *be = kzalloc(sizeof(struct backend_info), 66 GFP_KERNEL); 67 if (!be) { 68 xenbus_dev_fatal(dev, -ENOMEM, 69 "allocating backend structure"); 70 return -ENOMEM; 71 } 72 73 be->dev = dev; 74 dev_set_drvdata(&dev->dev, be); 75 76 sg = 1; 77 78 do { 79 err = xenbus_transaction_start(&xbt); 80 if (err) { 81 xenbus_dev_fatal(dev, err, "starting transaction"); 82 goto fail; 83 } 84 85 err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg); 86 if (err) { 87 message = "writing feature-sg"; 88 goto abort_transaction; 89 } 90 91 err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", 92 "%d", sg); 93 if (err) { 94 message = "writing feature-gso-tcpv4"; 95 goto abort_transaction; 96 } 97 98 /* We support rx-copy path. */ 99 err = xenbus_printf(xbt, dev->nodename, 100 "feature-rx-copy", "%d", 1); 101 if (err) { 102 message = "writing feature-rx-copy"; 103 goto abort_transaction; 104 } 105 106 /* 107 * We don't support rx-flip path (except old guests who don't 108 * grok this feature flag). 109 */ 110 err = xenbus_printf(xbt, dev->nodename, 111 "feature-rx-flip", "%d", 0); 112 if (err) { 113 message = "writing feature-rx-flip"; 114 goto abort_transaction; 115 } 116 117 err = xenbus_transaction_end(xbt, 0); 118 } while (err == -EAGAIN); 119 120 if (err) { 121 xenbus_dev_fatal(dev, err, "completing transaction"); 122 goto fail; 123 } 124 125 /* 126 * Split event channels support, this is optional so it is not 127 * put inside the above loop. 128 */ 129 err = xenbus_printf(XBT_NIL, dev->nodename, 130 "feature-split-event-channels", 131 "%u", separate_tx_rx_irq); 132 if (err) 133 pr_debug("Error writing feature-split-event-channels\n"); 134 135 err = xenbus_switch_state(dev, XenbusStateInitWait); 136 if (err) 137 goto fail; 138 139 /* This kicks hotplug scripts, so do it immediately. */ 140 backend_create_xenvif(be); 141 142 return 0; 143 144 abort_transaction: 145 xenbus_transaction_end(xbt, 1); 146 xenbus_dev_fatal(dev, err, "%s", message); 147 fail: 148 pr_debug("failed\n"); 149 netback_remove(dev); 150 return err; 151 } 152 153 154 /* 155 * Handle the creation of the hotplug script environment. We add the script 156 * and vif variables to the environment, for the benefit of the vif-* hotplug 157 * scripts. 158 */ 159 static int netback_uevent(struct xenbus_device *xdev, 160 struct kobj_uevent_env *env) 161 { 162 struct backend_info *be = dev_get_drvdata(&xdev->dev); 163 char *val; 164 165 val = xenbus_read(XBT_NIL, xdev->nodename, "script", NULL); 166 if (IS_ERR(val)) { 167 int err = PTR_ERR(val); 168 xenbus_dev_fatal(xdev, err, "reading script"); 169 return err; 170 } else { 171 if (add_uevent_var(env, "script=%s", val)) { 172 kfree(val); 173 return -ENOMEM; 174 } 175 kfree(val); 176 } 177 178 if (!be || !be->vif) 179 return 0; 180 181 return add_uevent_var(env, "vif=%s", be->vif->dev->name); 182 } 183 184 185 static void backend_create_xenvif(struct backend_info *be) 186 { 187 int err; 188 long handle; 189 struct xenbus_device *dev = be->dev; 190 191 if (be->vif != NULL) 192 return; 193 194 err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle); 195 if (err != 1) { 196 xenbus_dev_fatal(dev, err, "reading handle"); 197 return; 198 } 199 200 be->vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle); 201 if (IS_ERR(be->vif)) { 202 err = PTR_ERR(be->vif); 203 be->vif = NULL; 204 xenbus_dev_fatal(dev, err, "creating interface"); 205 return; 206 } 207 208 kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE); 209 } 210 211 212 static void disconnect_backend(struct xenbus_device *dev) 213 { 214 struct backend_info *be = dev_get_drvdata(&dev->dev); 215 216 if (be->vif) 217 xenvif_disconnect(be->vif); 218 } 219 220 static void destroy_backend(struct xenbus_device *dev) 221 { 222 struct backend_info *be = dev_get_drvdata(&dev->dev); 223 224 if (be->vif) { 225 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); 226 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); 227 xenvif_free(be->vif); 228 be->vif = NULL; 229 } 230 } 231 232 /** 233 * Callback received when the frontend's state changes. 234 */ 235 static void frontend_changed(struct xenbus_device *dev, 236 enum xenbus_state frontend_state) 237 { 238 struct backend_info *be = dev_get_drvdata(&dev->dev); 239 240 pr_debug("frontend state %s\n", xenbus_strstate(frontend_state)); 241 242 be->frontend_state = frontend_state; 243 244 switch (frontend_state) { 245 case XenbusStateInitialising: 246 if (dev->state == XenbusStateClosed) { 247 pr_info("%s: prepare for reconnect\n", dev->nodename); 248 xenbus_switch_state(dev, XenbusStateInitWait); 249 } 250 break; 251 252 case XenbusStateInitialised: 253 break; 254 255 case XenbusStateConnected: 256 if (dev->state == XenbusStateConnected) 257 break; 258 if (be->vif) 259 connect(be); 260 break; 261 262 case XenbusStateClosing: 263 disconnect_backend(dev); 264 xenbus_switch_state(dev, XenbusStateClosing); 265 break; 266 267 case XenbusStateClosed: 268 xenbus_switch_state(dev, XenbusStateClosed); 269 if (xenbus_dev_is_online(dev)) 270 break; 271 destroy_backend(dev); 272 /* fall through if not online */ 273 case XenbusStateUnknown: 274 device_unregister(&dev->dev); 275 break; 276 277 default: 278 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 279 frontend_state); 280 break; 281 } 282 } 283 284 285 static void xen_net_read_rate(struct xenbus_device *dev, 286 unsigned long *bytes, unsigned long *usec) 287 { 288 char *s, *e; 289 unsigned long b, u; 290 char *ratestr; 291 292 /* Default to unlimited bandwidth. */ 293 *bytes = ~0UL; 294 *usec = 0; 295 296 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL); 297 if (IS_ERR(ratestr)) 298 return; 299 300 s = ratestr; 301 b = simple_strtoul(s, &e, 10); 302 if ((s == e) || (*e != ',')) 303 goto fail; 304 305 s = e + 1; 306 u = simple_strtoul(s, &e, 10); 307 if ((s == e) || (*e != '\0')) 308 goto fail; 309 310 *bytes = b; 311 *usec = u; 312 313 kfree(ratestr); 314 return; 315 316 fail: 317 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n"); 318 kfree(ratestr); 319 } 320 321 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) 322 { 323 char *s, *e, *macstr; 324 int i; 325 326 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL); 327 if (IS_ERR(macstr)) 328 return PTR_ERR(macstr); 329 330 for (i = 0; i < ETH_ALEN; i++) { 331 mac[i] = simple_strtoul(s, &e, 16); 332 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) { 333 kfree(macstr); 334 return -ENOENT; 335 } 336 s = e+1; 337 } 338 339 kfree(macstr); 340 return 0; 341 } 342 343 static void unregister_hotplug_status_watch(struct backend_info *be) 344 { 345 if (be->have_hotplug_status_watch) { 346 unregister_xenbus_watch(&be->hotplug_status_watch); 347 kfree(be->hotplug_status_watch.node); 348 } 349 be->have_hotplug_status_watch = 0; 350 } 351 352 static void hotplug_status_changed(struct xenbus_watch *watch, 353 const char **vec, 354 unsigned int vec_size) 355 { 356 struct backend_info *be = container_of(watch, 357 struct backend_info, 358 hotplug_status_watch); 359 char *str; 360 unsigned int len; 361 362 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len); 363 if (IS_ERR(str)) 364 return; 365 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) { 366 xenbus_switch_state(be->dev, XenbusStateConnected); 367 /* Not interested in this watch anymore. */ 368 unregister_hotplug_status_watch(be); 369 } 370 kfree(str); 371 } 372 373 static void connect(struct backend_info *be) 374 { 375 int err; 376 struct xenbus_device *dev = be->dev; 377 378 err = connect_rings(be); 379 if (err) 380 return; 381 382 err = xen_net_read_mac(dev, be->vif->fe_dev_addr); 383 if (err) { 384 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename); 385 return; 386 } 387 388 xen_net_read_rate(dev, &be->vif->credit_bytes, 389 &be->vif->credit_usec); 390 be->vif->remaining_credit = be->vif->credit_bytes; 391 392 unregister_hotplug_status_watch(be); 393 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, 394 hotplug_status_changed, 395 "%s/%s", dev->nodename, "hotplug-status"); 396 if (err) { 397 /* Switch now, since we can't do a watch. */ 398 xenbus_switch_state(dev, XenbusStateConnected); 399 } else { 400 be->have_hotplug_status_watch = 1; 401 } 402 403 netif_wake_queue(be->vif->dev); 404 } 405 406 407 static int connect_rings(struct backend_info *be) 408 { 409 struct xenvif *vif = be->vif; 410 struct xenbus_device *dev = be->dev; 411 unsigned long tx_ring_ref, rx_ring_ref; 412 unsigned int tx_evtchn, rx_evtchn, rx_copy; 413 int err; 414 int val; 415 416 err = xenbus_gather(XBT_NIL, dev->otherend, 417 "tx-ring-ref", "%lu", &tx_ring_ref, 418 "rx-ring-ref", "%lu", &rx_ring_ref, NULL); 419 if (err) { 420 xenbus_dev_fatal(dev, err, 421 "reading %s/ring-ref", 422 dev->otherend); 423 return err; 424 } 425 426 /* Try split event channels first, then single event channel. */ 427 err = xenbus_gather(XBT_NIL, dev->otherend, 428 "event-channel-tx", "%u", &tx_evtchn, 429 "event-channel-rx", "%u", &rx_evtchn, NULL); 430 if (err < 0) { 431 err = xenbus_scanf(XBT_NIL, dev->otherend, 432 "event-channel", "%u", &tx_evtchn); 433 if (err < 0) { 434 xenbus_dev_fatal(dev, err, 435 "reading %s/event-channel(-tx/rx)", 436 dev->otherend); 437 return err; 438 } 439 rx_evtchn = tx_evtchn; 440 } 441 442 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u", 443 &rx_copy); 444 if (err == -ENOENT) { 445 err = 0; 446 rx_copy = 0; 447 } 448 if (err < 0) { 449 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy", 450 dev->otherend); 451 return err; 452 } 453 if (!rx_copy) 454 return -EOPNOTSUPP; 455 456 if (vif->dev->tx_queue_len != 0) { 457 if (xenbus_scanf(XBT_NIL, dev->otherend, 458 "feature-rx-notify", "%d", &val) < 0) 459 val = 0; 460 if (val) 461 vif->can_queue = 1; 462 else 463 /* Must be non-zero for pfifo_fast to work. */ 464 vif->dev->tx_queue_len = 1; 465 } 466 467 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg", 468 "%d", &val) < 0) 469 val = 0; 470 vif->can_sg = !!val; 471 472 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4", 473 "%d", &val) < 0) 474 val = 0; 475 vif->gso = !!val; 476 477 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix", 478 "%d", &val) < 0) 479 val = 0; 480 vif->gso_prefix = !!val; 481 482 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload", 483 "%d", &val) < 0) 484 val = 0; 485 vif->csum = !val; 486 487 /* Map the shared frame, irq etc. */ 488 err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, 489 tx_evtchn, rx_evtchn); 490 if (err) { 491 xenbus_dev_fatal(dev, err, 492 "mapping shared-frames %lu/%lu port tx %u rx %u", 493 tx_ring_ref, rx_ring_ref, 494 tx_evtchn, rx_evtchn); 495 return err; 496 } 497 return 0; 498 } 499 500 501 /* ** Driver Registration ** */ 502 503 504 static const struct xenbus_device_id netback_ids[] = { 505 { "vif" }, 506 { "" } 507 }; 508 509 510 static DEFINE_XENBUS_DRIVER(netback, , 511 .probe = netback_probe, 512 .remove = netback_remove, 513 .uevent = netback_uevent, 514 .otherend_changed = frontend_changed, 515 ); 516 517 int xenvif_xenbus_init(void) 518 { 519 return xenbus_register_backend(&netback_driver); 520 } 521 522 void xenvif_xenbus_fini(void) 523 { 524 return xenbus_unregister_driver(&netback_driver); 525 } 526