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
netback_remove(struct xenbus_device * dev)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 */
netback_probe(struct xenbus_device * dev,const struct xenbus_device_id * id)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 */
netback_uevent(struct xenbus_device * xdev,struct kobj_uevent_env * env)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
backend_create_xenvif(struct backend_info * be)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
disconnect_backend(struct xenbus_device * dev)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 */
frontend_changed(struct xenbus_device * dev,enum xenbus_state frontend_state)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
xen_net_read_rate(struct xenbus_device * dev,unsigned long * bytes,unsigned long * usec)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
xen_net_read_mac(struct xenbus_device * dev,u8 mac[])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
unregister_hotplug_status_watch(struct backend_info * be)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
hotplug_status_changed(struct xenbus_watch * watch,const char ** vec,unsigned int vec_size)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
connect(struct backend_info * be)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
connect_rings(struct backend_info * be)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
xenvif_xenbus_init(void)484 int xenvif_xenbus_init(void)
485 {
486 return xenbus_register_backend(&netback_driver);
487 }
488