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_disconnect(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 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); 218 xenvif_disconnect(be->vif); 219 be->vif = NULL; 220 } 221 } 222 223 /** 224 * Callback received when the frontend's state changes. 225 */ 226 static void frontend_changed(struct xenbus_device *dev, 227 enum xenbus_state frontend_state) 228 { 229 struct backend_info *be = dev_get_drvdata(&dev->dev); 230 231 pr_debug("frontend state %s\n", xenbus_strstate(frontend_state)); 232 233 be->frontend_state = frontend_state; 234 235 switch (frontend_state) { 236 case XenbusStateInitialising: 237 if (dev->state == XenbusStateClosed) { 238 pr_info("%s: prepare for reconnect\n", dev->nodename); 239 xenbus_switch_state(dev, XenbusStateInitWait); 240 } 241 break; 242 243 case XenbusStateInitialised: 244 break; 245 246 case XenbusStateConnected: 247 if (dev->state == XenbusStateConnected) 248 break; 249 backend_create_xenvif(be); 250 if (be->vif) 251 connect(be); 252 break; 253 254 case XenbusStateClosing: 255 if (be->vif) 256 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); 257 disconnect_backend(dev); 258 xenbus_switch_state(dev, XenbusStateClosing); 259 break; 260 261 case XenbusStateClosed: 262 xenbus_switch_state(dev, XenbusStateClosed); 263 if (xenbus_dev_is_online(dev)) 264 break; 265 /* fall through if not online */ 266 case XenbusStateUnknown: 267 device_unregister(&dev->dev); 268 break; 269 270 default: 271 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 272 frontend_state); 273 break; 274 } 275 } 276 277 278 static void xen_net_read_rate(struct xenbus_device *dev, 279 unsigned long *bytes, unsigned long *usec) 280 { 281 char *s, *e; 282 unsigned long b, u; 283 char *ratestr; 284 285 /* Default to unlimited bandwidth. */ 286 *bytes = ~0UL; 287 *usec = 0; 288 289 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL); 290 if (IS_ERR(ratestr)) 291 return; 292 293 s = ratestr; 294 b = simple_strtoul(s, &e, 10); 295 if ((s == e) || (*e != ',')) 296 goto fail; 297 298 s = e + 1; 299 u = simple_strtoul(s, &e, 10); 300 if ((s == e) || (*e != '\0')) 301 goto fail; 302 303 *bytes = b; 304 *usec = u; 305 306 kfree(ratestr); 307 return; 308 309 fail: 310 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n"); 311 kfree(ratestr); 312 } 313 314 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) 315 { 316 char *s, *e, *macstr; 317 int i; 318 319 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL); 320 if (IS_ERR(macstr)) 321 return PTR_ERR(macstr); 322 323 for (i = 0; i < ETH_ALEN; i++) { 324 mac[i] = simple_strtoul(s, &e, 16); 325 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) { 326 kfree(macstr); 327 return -ENOENT; 328 } 329 s = e+1; 330 } 331 332 kfree(macstr); 333 return 0; 334 } 335 336 static void unregister_hotplug_status_watch(struct backend_info *be) 337 { 338 if (be->have_hotplug_status_watch) { 339 unregister_xenbus_watch(&be->hotplug_status_watch); 340 kfree(be->hotplug_status_watch.node); 341 } 342 be->have_hotplug_status_watch = 0; 343 } 344 345 static void hotplug_status_changed(struct xenbus_watch *watch, 346 const char **vec, 347 unsigned int vec_size) 348 { 349 struct backend_info *be = container_of(watch, 350 struct backend_info, 351 hotplug_status_watch); 352 char *str; 353 unsigned int len; 354 355 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len); 356 if (IS_ERR(str)) 357 return; 358 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) { 359 xenbus_switch_state(be->dev, XenbusStateConnected); 360 /* Not interested in this watch anymore. */ 361 unregister_hotplug_status_watch(be); 362 } 363 kfree(str); 364 } 365 366 static void connect(struct backend_info *be) 367 { 368 int err; 369 struct xenbus_device *dev = be->dev; 370 371 err = connect_rings(be); 372 if (err) 373 return; 374 375 err = xen_net_read_mac(dev, be->vif->fe_dev_addr); 376 if (err) { 377 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename); 378 return; 379 } 380 381 xen_net_read_rate(dev, &be->vif->credit_bytes, 382 &be->vif->credit_usec); 383 be->vif->remaining_credit = be->vif->credit_bytes; 384 385 unregister_hotplug_status_watch(be); 386 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, 387 hotplug_status_changed, 388 "%s/%s", dev->nodename, "hotplug-status"); 389 if (err) { 390 /* Switch now, since we can't do a watch. */ 391 xenbus_switch_state(dev, XenbusStateConnected); 392 } else { 393 be->have_hotplug_status_watch = 1; 394 } 395 396 netif_wake_queue(be->vif->dev); 397 } 398 399 400 static int connect_rings(struct backend_info *be) 401 { 402 struct xenvif *vif = be->vif; 403 struct xenbus_device *dev = be->dev; 404 unsigned long tx_ring_ref, rx_ring_ref; 405 unsigned int tx_evtchn, rx_evtchn, rx_copy; 406 int err; 407 int val; 408 409 err = xenbus_gather(XBT_NIL, dev->otherend, 410 "tx-ring-ref", "%lu", &tx_ring_ref, 411 "rx-ring-ref", "%lu", &rx_ring_ref, NULL); 412 if (err) { 413 xenbus_dev_fatal(dev, err, 414 "reading %s/ring-ref", 415 dev->otherend); 416 return err; 417 } 418 419 /* Try split event channels first, then single event channel. */ 420 err = xenbus_gather(XBT_NIL, dev->otherend, 421 "event-channel-tx", "%u", &tx_evtchn, 422 "event-channel-rx", "%u", &rx_evtchn, NULL); 423 if (err < 0) { 424 err = xenbus_scanf(XBT_NIL, dev->otherend, 425 "event-channel", "%u", &tx_evtchn); 426 if (err < 0) { 427 xenbus_dev_fatal(dev, err, 428 "reading %s/event-channel(-tx/rx)", 429 dev->otherend); 430 return err; 431 } 432 rx_evtchn = tx_evtchn; 433 } 434 435 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u", 436 &rx_copy); 437 if (err == -ENOENT) { 438 err = 0; 439 rx_copy = 0; 440 } 441 if (err < 0) { 442 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy", 443 dev->otherend); 444 return err; 445 } 446 if (!rx_copy) 447 return -EOPNOTSUPP; 448 449 if (vif->dev->tx_queue_len != 0) { 450 if (xenbus_scanf(XBT_NIL, dev->otherend, 451 "feature-rx-notify", "%d", &val) < 0) 452 val = 0; 453 if (val) 454 vif->can_queue = 1; 455 else 456 /* Must be non-zero for pfifo_fast to work. */ 457 vif->dev->tx_queue_len = 1; 458 } 459 460 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg", 461 "%d", &val) < 0) 462 val = 0; 463 vif->can_sg = !!val; 464 465 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4", 466 "%d", &val) < 0) 467 val = 0; 468 vif->gso = !!val; 469 470 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix", 471 "%d", &val) < 0) 472 val = 0; 473 vif->gso_prefix = !!val; 474 475 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload", 476 "%d", &val) < 0) 477 val = 0; 478 vif->csum = !val; 479 480 /* Map the shared frame, irq etc. */ 481 err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, 482 tx_evtchn, rx_evtchn); 483 if (err) { 484 xenbus_dev_fatal(dev, err, 485 "mapping shared-frames %lu/%lu port tx %u rx %u", 486 tx_ring_ref, rx_ring_ref, 487 tx_evtchn, rx_evtchn); 488 return err; 489 } 490 return 0; 491 } 492 493 494 /* ** Driver Registration ** */ 495 496 497 static const struct xenbus_device_id netback_ids[] = { 498 { "vif" }, 499 { "" } 500 }; 501 502 503 static DEFINE_XENBUS_DRIVER(netback, , 504 .probe = netback_probe, 505 .remove = netback_remove, 506 .uevent = netback_uevent, 507 .otherend_changed = frontend_changed, 508 ); 509 510 int xenvif_xenbus_init(void) 511 { 512 return xenbus_register_backend(&netback_driver); 513 } 514 515 void xenvif_xenbus_fini(void) 516 { 517 return xenbus_unregister_driver(&netback_driver); 518 } 519