[mirror_ubuntu-jammy-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;
	}

	/*
	 * Split event channels support, this is optional so it is not
	 * put inside the above loop.
	 */
	err = xenbus_printf(XBT_NIL, dev->nodename,
			    "feature-split-event-channels",
			    "%u", separate_tx_rx_irq);
	if (err)
		pr_debug("Error writing feature-split-event-channels");

	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 tx_evtchn, rx_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, NULL);
	if (err) {
		xenbus_dev_fatal(dev, err,
				 "reading %s/ring-ref",
				 dev->otherend);
		return err;
	}

	/* Try split event channels first, then single event channel. */
	err = xenbus_gather(XBT_NIL, dev->otherend,
			    "event-channel-tx", "%u", &tx_evtchn,
			    "event-channel-rx", "%u", &rx_evtchn, NULL);
	if (err < 0) {
		err = xenbus_scanf(XBT_NIL, dev->otherend,
				   "event-channel", "%u", &tx_evtchn);
		if (err < 0) {
			xenbus_dev_fatal(dev, err,
					 "reading %s/event-channel(-tx/rx)",
					 dev->otherend);
			return err;
		}
		rx_evtchn = tx_evtchn;
	}

	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,
			     tx_evtchn, rx_evtchn);
	if (err) {
		xenbus_dev_fatal(dev, err,
				 "mapping shared-frames %lu/%lu port tx %u rx %u",
				 tx_ring_ref, rx_ring_ref,
				 tx_evtchn, rx_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
e1f00a69 WL	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");
	134
f942dc25 IC	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");
	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", 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	printk(KERN_INFO "%s: %s: prepare for reconnect\n",
239	__func__, dev->nodename);
240	xenbus_switch_state(dev, XenbusStateInitWait);
241	}
242	break;
243
244	case XenbusStateInitialised:
245	break;
246
247	case XenbusStateConnected:
248	if (dev->state == XenbusStateConnected)
249	break;
250	backend_create_xenvif(be);
251	if (be->vif)
252	connect(be);
253	break;
254
255	case XenbusStateClosing:
256	if (be->vif)
257	kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
258	disconnect_backend(dev);
259	xenbus_switch_state(dev, XenbusStateClosing);
260	break;
261
262	case XenbusStateClosed:
263	xenbus_switch_state(dev, XenbusStateClosed);
264	if (xenbus_dev_is_online(dev))
265	break;
266	/* fall through if not online */
267	case XenbusStateUnknown:
268	device_unregister(&dev->dev);
269	break;
270
271	default:
272	xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
273	frontend_state);
274	break;
275	}
276	}
277
278
279	static void xen_net_read_rate(struct xenbus_device *dev,
280	unsigned long bytes, unsigned long usec)
281	{
282	char s, e;
283	unsigned long b, u;
284	char *ratestr;
285
286	/* Default to unlimited bandwidth. */
287	*bytes = ~0UL;
288	*usec = 0;
289
290	ratestr = xenbus_read(XBT_NIL, dev->nodename, "rate", NULL);
291	if (IS_ERR(ratestr))
292	return;
293
294	s = ratestr;
295	b = simple_strtoul(s, &e, 10);
296	if ((s == e) \|\| (*e != ','))
297	goto fail;
298
299	s = e + 1;
300	u = simple_strtoul(s, &e, 10);
301	if ((s == e) \|\| (*e != '\0'))
302	goto fail;
303
304	*bytes = b;
305	*usec = u;
306
307	kfree(ratestr);
308	return;
309
310	fail:
311	pr_warn("Failed to parse network rate limit. Traffic unlimited.\n");
312	kfree(ratestr);
313	}
314
315	static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
316	{
317	char s, e, *macstr;
318	int i;
319
320	macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
321	if (IS_ERR(macstr))
322	return PTR_ERR(macstr);
323
324	for (i = 0; i < ETH_ALEN; i++) {
325	mac[i] = simple_strtoul(s, &e, 16);
326	if ((s == e) \|\| (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
327	kfree(macstr);
328	return -ENOENT;
329	}
330	s = e+1;
331	}
332
333	kfree(macstr);
334	return 0;
335	}
336
337	static void unregister_hotplug_status_watch(struct backend_info *be)
338	{
339	if (be->have_hotplug_status_watch) {
340	unregister_xenbus_watch(&be->hotplug_status_watch);
341	kfree(be->hotplug_status_watch.node);
342	}
343	be->have_hotplug_status_watch = 0;
344	}
345
346	static void hotplug_status_changed(struct xenbus_watch *watch,
347	const char **vec,
348	unsigned int vec_size)
349	{
350	struct backend_info *be = container_of(watch,
351	struct backend_info,
352	hotplug_status_watch);
353	char *str;
354	unsigned int len;
355
356	str = xenbus_read(XBT_NIL, be->dev->nodename, "hotplug-status", &len);
357	if (IS_ERR(str))
358	return;
359	if (len == sizeof("connected")-1 && !memcmp(str, "connected", len)) {
360	xenbus_switch_state(be->dev, XenbusStateConnected);
361	/* Not interested in this watch anymore. */
362	unregister_hotplug_status_watch(be);
363	}
364	kfree(str);
365	}
366
367	static void connect(struct backend_info *be)
368	{
369	int err;
370	struct xenbus_device *dev = be->dev;
371
372	err = connect_rings(be);
373	if (err)
374	return;
375
376	err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
377	if (err) {
378	xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
379	return;
380	}
381
382	xen_net_read_rate(dev, &be->vif->credit_bytes,
383	&be->vif->credit_usec);
384	be->vif->remaining_credit = be->vif->credit_bytes;
385
386	unregister_hotplug_status_watch(be);
387	err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
388	hotplug_status_changed,
389	"%s/%s", dev->nodename, "hotplug-status");
390	if (err) {
391	/* Switch now, since we can't do a watch. */
392	xenbus_switch_state(dev, XenbusStateConnected);
393	} else {
394	be->have_hotplug_status_watch = 1;
395	}
396
397	netif_wake_queue(be->vif->dev);
398	}
399
400
401	static int connect_rings(struct backend_info *be)
402	{
403	struct xenvif *vif = be->vif;
404	struct xenbus_device *dev = be->dev;
405	unsigned long tx_ring_ref, rx_ring_ref;
e1f00a69	406	unsigned int tx_evtchn, rx_evtchn, rx_copy;
f942dc25 IC	407	int err;
	408	int val;
	409
	410	err = xenbus_gather(XBT_NIL, dev->otherend,
	411	"tx-ring-ref", "%lu", &tx_ring_ref,
e1f00a69	412	"rx-ring-ref", "%lu", &rx_ring_ref, NULL);
f942dc25 IC	413	if (err) {
f942dc25 IC	414	xenbus_dev_fatal(dev, err,
e1f00a69	415	"reading %s/ring-ref",
f942dc25 IC	416	dev->otherend);
	417	return err;
	418	}
	419
e1f00a69 WL	420	/* Try split event channels first, then single event channel. */
	421	err = xenbus_gather(XBT_NIL, dev->otherend,
	422	"event-channel-tx", "%u", &tx_evtchn,
	423	"event-channel-rx", "%u", &rx_evtchn, NULL);
	424	if (err < 0) {
	425	err = xenbus_scanf(XBT_NIL, dev->otherend,
	426	"event-channel", "%u", &tx_evtchn);
	427	if (err < 0) {
	428	xenbus_dev_fatal(dev, err,
	429	"reading %s/event-channel(-tx/rx)",
	430	dev->otherend);
	431	return err;
	432	}
	433	rx_evtchn = tx_evtchn;
	434	}
	435
f942dc25 IC	436	err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u",
	437	&rx_copy);
	438	if (err == -ENOENT) {
	439	err = 0;
	440	rx_copy = 0;
	441	}
	442	if (err < 0) {
	443	xenbus_dev_fatal(dev, err, "reading %s/request-rx-copy",
	444	dev->otherend);
	445	return err;
	446	}
	447	if (!rx_copy)
	448	return -EOPNOTSUPP;
	449
	450	if (vif->dev->tx_queue_len != 0) {
	451	if (xenbus_scanf(XBT_NIL, dev->otherend,
	452	"feature-rx-notify", "%d", &val) < 0)
	453	val = 0;
	454	if (val)
	455	vif->can_queue = 1;
	456	else
	457	/* Must be non-zero for pfifo_fast to work. */
	458	vif->dev->tx_queue_len = 1;
	459	}
	460
	461	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg",
	462	"%d", &val) < 0)
	463	val = 0;
	464	vif->can_sg = !!val;
	465
	466	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4",
	467	"%d", &val) < 0)
	468	val = 0;
	469	vif->gso = !!val;
	470
	471	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-gso-tcpv4-prefix",
	472	"%d", &val) < 0)
	473	val = 0;
	474	vif->gso_prefix = !!val;
	475
	476	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-no-csum-offload",
	477	"%d", &val) < 0)
	478	val = 0;
	479	vif->csum = !val;
	480
	481	/* Map the shared frame, irq etc. */
e1f00a69 WL	482	err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref,
e1f00a69 WL	483	tx_evtchn, rx_evtchn);
f942dc25 IC	484	if (err) {
f942dc25 IC	485	xenbus_dev_fatal(dev, err,
e1f00a69 WL	486	"mapping shared-frames %lu/%lu port tx %u rx %u",
	487	tx_ring_ref, rx_ring_ref,
	488	tx_evtchn, rx_evtchn);
f942dc25 IC	489	return err;
	490	}
	491	return 0;
	492	}
	493
	494
	495	/* Driver Registration */
	496
	497
	498	static const struct xenbus_device_id netback_ids[] = {
	499	{ "vif" },
	500	{ "" }
	501	};
	502
	503
73db144b	504	static DEFINE_XENBUS_DRIVER(netback, ,
f942dc25 IC	505	.probe = netback_probe,
	506	.remove = netback_remove,
	507	.uevent = netback_uevent,
	508	.otherend_changed = frontend_changed,
73db144b	509	);
f942dc25 IC	510
	511	int xenvif_xenbus_init(void)
	512	{
73db144b	513	return xenbus_register_backend(&netback_driver);
f942dc25	514	}
b103f358 WL	515
	516	void xenvif_xenbus_fini(void)
	517	{
	518	return xenbus_unregister_driver(&netback_driver);
	519	}