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 err = xenbus_switch_state(dev, XenbusStateInitWait); 126 if (err) 127 goto fail; 128 129 /* This kicks hotplug scripts, so do it immediately. */ 130 backend_create_xenvif(be); 131 132 return 0; 133 134 abort_transaction: 135 xenbus_transaction_end(xbt, 1); 136 xenbus_dev_fatal(dev, err, "%s", message); 137 fail: 138 pr_debug("failed"); 139 netback_remove(dev); 140 return err; 141 } 142 143 144 /* 145 * Handle the creation of the hotplug script environment. We add the script 146 * and vif variables to the environment, for the benefit of the vif-* hotplug 147 * scripts. 148 */ 149 static int netback_uevent(struct xenbus_device *xdev, 150 struct kobj_uevent_env *env) 151 { 152 struct backend_info *be = dev_get_drvdata(&xdev->dev); 153 char *val; 154 155 val = xenbus_read(XBT_NIL, xdev->nodename, "script", NULL); 156 if (IS_ERR(val)) { 157 int err = PTR_ERR(val); 158 xenbus_dev_fatal(xdev, err, "reading script"); 159 return err; 160 } else { 161 if (add_uevent_var(env, "script=%s", val)) { 162 kfree(val); 163 return -ENOMEM; 164 } 165 kfree(val); 166 } 167 168 if (!be || !be->vif) 169 return 0; 170 171 return add_uevent_var(env, "vif=%s", be->vif->dev->name); 172 } 173 174 175 static void backend_create_xenvif(struct backend_info *be) 176 { 177 int err; 178 long handle; 179 struct xenbus_device *dev = be->dev; 180 181 if (be->vif != NULL) 182 return; 183 184 err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle); 185 if (err != 1) { 186 xenbus_dev_fatal(dev, err, "reading handle"); 187 return; 188 } 189 190 be->vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle); 191 if (IS_ERR(be->vif)) { 192 err = PTR_ERR(be->vif); 193 be->vif = NULL; 194 xenbus_dev_fatal(dev, err, "creating interface"); 195 return; 196 } 197 198 kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE); 199 } 200 201 202 static void disconnect_backend(struct xenbus_device *dev) 203 { 204 struct backend_info *be = dev_get_drvdata(&dev->dev); 205 206 if (be->vif) { 207 xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status"); 208 xenvif_disconnect(be->vif); 209 be->vif = NULL; 210 } 211 } 212 213 /** 214 * Callback received when the frontend's state changes. 215 */ 216 static void frontend_changed(struct xenbus_device *dev, 217 enum xenbus_state frontend_state) 218 { 219 struct backend_info *be = dev_get_drvdata(&dev->dev); 220 221 pr_debug("frontend state %s", xenbus_strstate(frontend_state)); 222 223 be->frontend_state = frontend_state; 224 225 switch (frontend_state) { 226 case XenbusStateInitialising: 227 if (dev->state == XenbusStateClosed) { 228 printk(KERN_INFO "%s: %s: prepare for reconnect\n", 229 __func__, dev->nodename); 230 xenbus_switch_state(dev, XenbusStateInitWait); 231 } 232 break; 233 234 case XenbusStateInitialised: 235 break; 236 237 case XenbusStateConnected: 238 if (dev->state == XenbusStateConnected) 239 break; 240 backend_create_xenvif(be); 241 if (be->vif) 242 connect(be); 243 break; 244 245 case XenbusStateClosing: 246 if (be->vif) 247 kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE); 248 disconnect_backend(dev); 249 xenbus_switch_state(dev, XenbusStateClosing); 250 break; 251 252 case XenbusStateClosed: 253 xenbus_switch_state(dev, XenbusStateClosed); 254 if (xenbus_dev_is_online(dev)) 255 break; 256 /* fall through if not online */ 257 case XenbusStateUnknown: 258 device_unregister(&dev->dev); 259 break; 260 261 default: 262 xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", 263 frontend_state); 264 break; 265 } 266 } 267 268 269 static void xen_net_read_rate(struct xenbus_device *dev, 270 unsigned long *bytes, unsigned long *usec) 271 { 272 char *s, *e; 273 unsigned long b, u; 274 char *ratestr; 275 276 /* Default to unlimited bandwidth. */ 277 *bytes = ~0UL; 278 *usec = 0; 279 280 ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL); 281 if (IS_ERR(ratestr)) 282 return; 283 284 s = ratestr; 285 b = simple_strtoul(s, &e, 10); 286 if ((s == e) || (*e != ',')) 287 goto fail; 288 289 s = e + 1; 290 u = simple_strtoul(s, &e, 10); 291 if ((s == e) || (*e != '\0')) 292 goto fail; 293 294 *bytes = b; 295 *usec = u; 296 297 kfree(ratestr); 298 return; 299 300 fail: 301 pr_warn("Failed to parse network rate limit. Traffic unlimited.\n"); 302 kfree(ratestr); 303 } 304 305 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[]) 306 { 307 char *s, *e, *macstr; 308 int i; 309 310 macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL); 311 if (IS_ERR(macstr)) 312 return PTR_ERR(macstr); 313 314 for (i = 0; i < ETH_ALEN; i++) { 315 mac[i] = simple_strtoul(s, &e, 16); 316 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) { 317 kfree(macstr); 318 return -ENOENT; 319 } 320 s = e+1; 321 } 322 323 kfree(macstr); 324 return 0; 325 } 326 327 static void unregister_hotplug_status_watch(struct backend_info *be) 328 { 329 if (be->have_hotplug_status_watch) { 330 unregister_xenbus_watch(&be->hotplug_status_watch); 331 kfree(be->hotplug_status_watch.node); 332 } 333 be->have_hotplug_status_watch = 0; 334 } 335 336 static void hotplug_status_changed(struct xenbus_watch *watch, 337 const char **vec, 338 unsigned int vec_size) 339 { 340 struct backend_info *be = container_of(watch, 341 struct backend_info, 342 hotplug_status_watch); 343 char *str; 344 unsigned int len; 345 346 str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len); 347 if (IS_ERR(str)) 348 return; 349 if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) { 350 xenbus_switch_state(be->dev, XenbusStateConnected); 351 /* Not interested in this watch anymore. */ 352 unregister_hotplug_status_watch(be); 353 } 354 kfree(str); 355 } 356 357 static void connect(struct backend_info *be) 358 { 359 int err; 360 struct xenbus_device *dev = be->dev; 361 362 err = connect_rings(be); 363 if (err) 364 return; 365 366 err = xen_net_read_mac(dev, be->vif->fe_dev_addr); 367 if (err) { 368 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename); 369 return; 370 } 371 372 xen_net_read_rate(dev, &be->vif->credit_bytes, 373 &be->vif->credit_usec); 374 be->vif->remaining_credit = be->vif->credit_bytes; 375 376 unregister_hotplug_status_watch(be); 377 err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, 378 hotplug_status_changed, 379 "%s/%s", dev->nodename, "hotplug-status"); 380 if (err) { 381 /* Switch now, since we can't do a watch. */ 382 xenbus_switch_state(dev, XenbusStateConnected); 383 } else { 384 be->have_hotplug_status_watch = 1; 385 } 386 387 netif_wake_queue(be->vif->dev); 388 } 389 390 391 static int connect_rings(struct backend_info *be) 392 { 393 struct xenvif *vif = be->vif; 394 struct xenbus_device *dev = be->dev; 395 unsigned long tx_ring_ref, rx_ring_ref; 396 unsigned int evtchn, rx_copy; 397 int err; 398 int val; 399 400 err = xenbus_gather(XBT_NIL, dev->otherend, 401 "tx-ring-ref", "%lu", &tx_ring_ref, 402 "rx-ring-ref", "%lu", &rx_ring_ref, 403 "event-channel", "%u", &evtchn, NULL); 404 if (err) { 405 xenbus_dev_fatal(dev, err, 406 "reading %s/ring-ref and event-channel", 407 dev->otherend); 408 return err; 409 } 410 411 err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u", 412 &rx_copy); 413 if (err == -ENOENT) { 414 err = 0; 415 rx_copy = 0; 416 } 417 if (err < 0) { 418 xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy", 419 dev->otherend); 420 return err; 421 } 422 if (!rx_copy) 423 return -EOPNOTSUPP; 424 425 if (vif->dev->tx_queue_len != 0) { 426 if (xenbus_scanf(XBT_NIL, dev->otherend, 427 "feature-rx-notify", "%d", &val) < 0) 428 val = 0; 429 if (val) 430 vif->can_queue = 1; 431 else 432 /* Must be non-zero for pfifo_fast to work. */ 433 vif->dev->tx_queue_len = 1; 434 } 435 436 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg", 437 "%d", &val) < 0) 438 val = 0; 439 vif->can_sg = !!val; 440 441 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4", 442 "%d", &val) < 0) 443 val = 0; 444 vif->gso = !!val; 445 446 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix", 447 "%d", &val) < 0) 448 val = 0; 449 vif->gso_prefix = !!val; 450 451 if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload", 452 "%d", &val) < 0) 453 val = 0; 454 vif->csum = !val; 455 456 /* Map the shared frame, irq etc. */ 457 err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, evtchn); 458 if (err) { 459 xenbus_dev_fatal(dev, err, 460 "mapping shared-frames %lu/%lu port %u", 461 tx_ring_ref, rx_ring_ref, evtchn); 462 return err; 463 } 464 return 0; 465 } 466 467 468 /* ** Driver Registration ** */ 469 470 471 static const struct xenbus_device_id netback_ids[] = { 472 { "vif" }, 473 { "" } 474 }; 475 476 477 static DEFINE_XENBUS_DRIVER(netback, , 478 .probe = netback_probe, 479 .remove = netback_remove, 480 .uevent = netback_uevent, 481 .otherend_changed = frontend_changed, 482 ); 483 484 int xenvif_xenbus_init(void) 485 { 486 return xenbus_register_backend(&netback_driver); 487 } 488