[mirror_ubuntu-artful-kernel.git] / drivers / net / xen-netback / xenbus.c

/*
 * Xenbus code for netif backend
 *
 * Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
 * Copyright (C) 2005 XenSource Ltd
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "common.h"

struct backend_info {
	struct xenbus_device *dev;
	struct xenvif *vif;
	enum xenbus_state frontend_state;
	struct xenbus_watch hotplug_status_watch;
	u8 have_hotplug_status_watch:1;
};

static int connect_rings(struct backend_info *);
static void connect(struct backend_info *);
static void backend_create_xenvif(struct backend_info *be);
static void unregister_hotplug_status_watch(struct backend_info *be);

static int netback_remove(struct xenbus_device *dev)
{
	struct backend_info *be = dev_get_drvdata(&dev->dev);

	unregister_hotplug_status_watch(be);
	if (be->vif) {
		kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
		xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
		xenvif_disconnect(be->vif);
		be->vif = NULL;
	}
	kfree(be);
	dev_set_drvdata(&dev->dev, NULL);
	return 0;
}


/**
 * Entry point to this code when a new device is created.  Allocate the basic
 * structures and switch to InitWait.
 */
static int netback_probe(struct xenbus_device *dev,
			 const struct xenbus_device_id *id)
{
	const char *message;
	struct xenbus_transaction xbt;
	int err;
	int sg;
	struct backend_info *be = kzalloc(sizeof(struct backend_info),
					  GFP_KERNEL);
	if (!be) {
		xenbus_dev_fatal(dev, -ENOMEM,
				 "allocating backend structure");
		return -ENOMEM;
	}

	be->dev = dev;
	dev_set_drvdata(&dev->dev, be);

	sg = 1;

	do {
		err = xenbus_transaction_start(&xbt);
		if (err) {
			xenbus_dev_fatal(dev, err, "starting transaction");
			goto fail;
		}

		err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", sg);
		if (err) {
			message = "writing feature-sg";
			goto abort_transaction;
		}

		err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4",
				    "%d", sg);
		if (err) {
			message = "writing feature-gso-tcpv4";
			goto abort_transaction;
		}

		/* We support rx-copy path. */
		err = xenbus_printf(xbt, dev->nodename,
				    "feature-rx-copy", "%d", 1);
		if (err) {
			message = "writing feature-rx-copy";
			goto abort_transaction;
		}

		/*
		 * We don't support rx-flip path (except old guests who don't
		 * grok this feature flag).
		 */
		err = xenbus_printf(xbt, dev->nodename,
				    "feature-rx-flip", "%d", 0);
		if (err) {
			message = "writing feature-rx-flip";
			goto abort_transaction;
		}

		err = xenbus_transaction_end(xbt, 0);
	} while (err == -EAGAIN);

	if (err) {
		xenbus_dev_fatal(dev, err, "completing transaction");
		goto fail;
	}

	err = xenbus_switch_state(dev, XenbusStateInitWait);
	if (err)
		goto fail;

	/* This kicks hotplug scripts, so do it immediately. */
	backend_create_xenvif(be);

	return 0;

abort_transaction:
	xenbus_transaction_end(xbt, 1);
	xenbus_dev_fatal(dev, err, "%s", message);
fail:
	pr_debug("failed");
	netback_remove(dev);
	return err;
}


/*
 * Handle the creation of the hotplug script environment.  We add the script
 * and vif variables to the environment, for the benefit of the vif-* hotplug
 * scripts.
 */
static int netback_uevent(struct xenbus_device *xdev,
			  struct kobj_uevent_env *env)
{
	struct backend_info *be = dev_get_drvdata(&xdev->dev);
	char *val;

	val = xenbus_read(XBT_NIL, xdev->nodename, "script", NULL);
	if (IS_ERR(val)) {
		int err = PTR_ERR(val);
		xenbus_dev_fatal(xdev, err, "reading script");
		return err;
	} else {
		if (add_uevent_var(env, "script=%s", val)) {
			kfree(val);
			return -ENOMEM;
		}
		kfree(val);
	}

	if (!be || !be->vif)
		return 0;

	return add_uevent_var(env, "vif=%s", be->vif->dev->name);
}


static void backend_create_xenvif(struct backend_info *be)
{
	int err;
	long handle;
	struct xenbus_device *dev = be->dev;

	if (be->vif != NULL)
		return;

	err = xenbus_scanf(XBT_NIL, dev->nodename, "handle", "%li", &handle);
	if (err != 1) {
		xenbus_dev_fatal(dev, err, "reading handle");
		return;
	}

	be->vif = xenvif_alloc(&dev->dev, dev->otherend_id, handle);
	if (IS_ERR(be->vif)) {
		err = PTR_ERR(be->vif);
		be->vif = NULL;
		xenbus_dev_fatal(dev, err, "creating interface");
		return;
	}

	kobject_uevent(&dev->dev.kobj, KOBJ_ONLINE);
}


static void disconnect_backend(struct xenbus_device *dev)
{
	struct backend_info *be = dev_get_drvdata(&dev->dev);

	if (be->vif) {
		xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
		xenvif_disconnect(be->vif);
		be->vif = NULL;
	}
}

/**
 * Callback received when the frontend's state changes.
 */
static void frontend_changed(struct xenbus_device *dev,
			     enum xenbus_state frontend_state)
{
	struct backend_info *be = dev_get_drvdata(&dev->dev);

	pr_debug("frontend state %s", xenbus_strstate(frontend_state));

	be->frontend_state = frontend_state;

	switch (frontend_state) {
	case XenbusStateInitialising:
		if (dev->state == XenbusStateClosed) {
			printk(KERN_INFO "%s: %s: prepare for reconnect\n",
			       __func__, dev->nodename);
			xenbus_switch_state(dev, XenbusStateInitWait);
		}
		break;

	case XenbusStateInitialised:
		break;

	case XenbusStateConnected:
		if (dev->state == XenbusStateConnected)
			break;
		backend_create_xenvif(be);
		if (be->vif)
			connect(be);
		break;

	case XenbusStateClosing:
		if (be->vif)
			kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
		disconnect_backend(dev);
		xenbus_switch_state(dev, XenbusStateClosing);
		break;

	case XenbusStateClosed:
		xenbus_switch_state(dev, XenbusStateClosed);
		if (xenbus_dev_is_online(dev))
			break;
		/* fall through if not online */
	case XenbusStateUnknown:
		device_unregister(&dev->dev);
		break;

	default:
		xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
				 frontend_state);
		break;
	}
}


static void xen_net_read_rate(struct xenbus_device *dev,
			      unsigned long *bytes, unsigned long *usec)
{
	char *s, *e;
	unsigned long b, u;
	char *ratestr;

	/* Default to unlimited bandwidth. */
	*bytes = ~0UL;
	*usec = 0;

	ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
	if (IS_ERR(ratestr))
		return;

	s = ratestr;
	b = simple_strtoul(s, &e, 10);
	if ((s == e) || (*e != ','))
		goto fail;

	s = e + 1;
	u = simple_strtoul(s, &e, 10);
	if ((s == e) || (*e != '\0'))
		goto fail;

	*bytes = b;
	*usec = u;

	kfree(ratestr);
	return;

 fail:
	pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
	kfree(ratestr);
}

static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
{
	char *s, *e, *macstr;
	int i;

	macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
	if (IS_ERR(macstr))
		return PTR_ERR(macstr);

	for (i = 0; i < ETH_ALEN; i++) {
		mac[i] = simple_strtoul(s, &e, 16);
		if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
			kfree(macstr);
			return -ENOENT;
		}
		s = e+1;
	}

	kfree(macstr);
	return 0;
}

static void unregister_hotplug_status_watch(struct backend_info *be)
{
	if (be->have_hotplug_status_watch) {
		unregister_xenbus_watch(&be->hotplug_status_watch);
		kfree(be->hotplug_status_watch.node);
	}
	be->have_hotplug_status_watch = 0;
}

static void hotplug_status_changed(struct xenbus_watch *watch,
				   const char **vec,
				   unsigned int vec_size)
{
	struct backend_info *be = container_of(watch,
					       struct backend_info,
					       hotplug_status_watch);
	char *str;
	unsigned int len;

	str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
	if (IS_ERR(str))
		return;
	if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
		xenbus_switch_state(be->dev, XenbusStateConnected);
		/* Not interested in this watch anymore. */
		unregister_hotplug_status_watch(be);
	}
	kfree(str);
}

static void connect(struct backend_info *be)
{
	int err;
	struct xenbus_device *dev = be->dev;

	err = connect_rings(be);
	if (err)
		return;

	err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
	if (err) {
		xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
		return;
	}

	xen_net_read_rate(dev, &be->vif->credit_bytes,
			  &be->vif->credit_usec);
	be->vif->remaining_credit = be->vif->credit_bytes;

	unregister_hotplug_status_watch(be);
	err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
				   hotplug_status_changed,
				   "%s/%s", dev->nodename, "hotplug-status");
	if (err) {
		/* Switch now, since we can't do a watch. */
		xenbus_switch_state(dev, XenbusStateConnected);
	} else {
		be->have_hotplug_status_watch = 1;
	}

	netif_wake_queue(be->vif->dev);
}


static int connect_rings(struct backend_info *be)
{
	struct xenvif *vif = be->vif;
	struct xenbus_device *dev = be->dev;
	unsigned long tx_ring_ref, rx_ring_ref;
	unsigned int evtchn, rx_copy;
	int err;
	int val;

	err = xenbus_gather(XBT_NIL, dev->otherend,
			    "tx-ring-ref", "%lu", &tx_ring_ref,
			    "rx-ring-ref", "%lu", &rx_ring_ref,
			    "event-channel", "%u", &evtchn, NULL);
	if (err) {
		xenbus_dev_fatal(dev, err,
				 "reading %s/ring-ref and event-channel",
				 dev->otherend);
		return err;
	}

	err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
			   &rx_copy);
	if (err == -ENOENT) {
		err = 0;
		rx_copy = 0;
	}
	if (err < 0) {
		xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
				 dev->otherend);
		return err;
	}
	if (!rx_copy)
		return -EOPNOTSUPP;

	if (vif->dev->tx_queue_len != 0) {
		if (xenbus_scanf(XBT_NIL, dev->otherend,
				 "feature-rx-notify", "%d", &val) < 0)
			val = 0;
		if (val)
			vif->can_queue = 1;
		else
			/* Must be non-zero for pfifo_fast to work. */
			vif->dev->tx_queue_len = 1;
	}

	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
			 "%d", &val) < 0)
		val = 0;
	vif->can_sg = !!val;

	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
			 "%d", &val) < 0)
		val = 0;
	vif->gso = !!val;

	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix",
			 "%d", &val) < 0)
		val = 0;
	vif->gso_prefix = !!val;

	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
			 "%d", &val) < 0)
		val = 0;
	vif->csum = !val;

	/* Map the shared frame, irq etc. */
	err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, evtchn);
	if (err) {
		xenbus_dev_fatal(dev, err,
				 "mapping shared-frames %lu/%lu port %u",
				 tx_ring_ref, rx_ring_ref, evtchn);
		return err;
	}
	return 0;
}


/* ** Driver Registration ** */


static const struct xenbus_device_id netback_ids[] = {
	{ "vif" },
	{ "" }
};


static DEFINE_XENBUS_DRIVER(netback, ,
	.probe = netback_probe,
	.remove = netback_remove,
	.uevent = netback_uevent,
	.otherend_changed = frontend_changed,
);

int xenvif_xenbus_init(void)
{
	return xenbus_register_backend(&netback_driver);
}

void xenvif_xenbus_fini(void)
{
	return xenbus_unregister_driver(&netback_driver);
}
Commit	Line	Data
f942dc25 IC	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;
17938a69	29	u8 have_hotplug_status_watch:1;
f942dc25 IC	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
73db144b	477	static DEFINE_XENBUS_DRIVER(netback, ,
f942dc25 IC	478	.probe = netback_probe,
	479	.remove = netback_remove,
	480	.uevent = netback_uevent,
	481	.otherend_changed = frontend_changed,
73db144b	482	);
f942dc25 IC	483
	484	int xenvif_xenbus_init(void)
	485	{
73db144b	486	return xenbus_register_backend(&netback_driver);
f942dc25	487	}
b103f358 WL	488
	489	void xenvif_xenbus_fini(void)
	490	{
	491	return xenbus_unregister_driver(&netback_driver);
	492	}