xref: /linux/drivers/net/xen-netback/interface.c (revision c54ea4918c2b7722d7242ea53271356501988a9b) 
1 /*
2  * Network-device interface management.
3  *
4  * Copyright (c) 2004-2005, Keir Fraser
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License version 2
8  * as published by the Free Software Foundation; or, when distributed
9  * separately from the Linux kernel or incorporated into other
10  * software packages, subject to the following license:
11  *
12  * Permission is hereby granted, free of charge, to any person obtaining a copy
13  * of this source file (the "Software"), to deal in the Software without
14  * restriction, including without limitation the rights to use, copy, modify,
15  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
16  * and to permit persons to whom the Software is furnished to do so, subject to
17  * the following conditions:
18  *
19  * The above copyright notice and this permission notice shall be included in
20  * all copies or substantial portions of the Software.
21  *
22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
28  * IN THE SOFTWARE.
29  */
30 
31 #include "common.h"
32 
33 #include <linux/ethtool.h>
34 #include <linux/rtnetlink.h>
35 #include <linux/if_vlan.h>
36 
37 #include <xen/events.h>
38 #include <asm/xen/hypercall.h>
39 
40 #define XENVIF_QUEUE_LENGTH 32
41 
42 void xenvif_get(struct xenvif *vif)
43 {
44 	atomic_inc(&vif->refcnt);
45 }
46 
47 void xenvif_put(struct xenvif *vif)
48 {
49 	if (atomic_dec_and_test(&vif->refcnt))
50 		wake_up(&vif->waiting_to_free);
51 }
52 
53 int xenvif_schedulable(struct xenvif *vif)
54 {
55 	return netif_running(vif->dev) && netif_carrier_ok(vif->dev);
56 }
57 
58 static int xenvif_rx_schedulable(struct xenvif *vif)
59 {
60 	return xenvif_schedulable(vif) && !xen_netbk_rx_ring_full(vif);
61 }
62 
63 static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
64 {
65 	struct xenvif *vif = dev_id;
66 
67 	if (vif->netbk == NULL)
68 		return IRQ_NONE;
69 
70 	xen_netbk_schedule_xenvif(vif);
71 
72 	if (xenvif_rx_schedulable(vif))
73 		netif_wake_queue(vif->dev);
74 
75 	return IRQ_HANDLED;
76 }
77 
78 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
79 {
80 	struct xenvif *vif = netdev_priv(dev);
81 
82 	BUG_ON(skb->dev != dev);
83 
84 	if (vif->netbk == NULL)
85 		goto drop;
86 
87 	/* Drop the packet if the target domain has no receive buffers. */
88 	if (!xenvif_rx_schedulable(vif))
89 		goto drop;
90 
91 	/* Reserve ring slots for the worst-case number of fragments. */
92 	vif->rx_req_cons_peek += xen_netbk_count_skb_slots(vif, skb);
93 	xenvif_get(vif);
94 
95 	if (vif->can_queue && xen_netbk_must_stop_queue(vif))
96 		netif_stop_queue(dev);
97 
98 	xen_netbk_queue_tx_skb(vif, skb);
99 
100 	return NETDEV_TX_OK;
101 
102  drop:
103 	vif->dev->stats.tx_dropped++;
104 	dev_kfree_skb(skb);
105 	return NETDEV_TX_OK;
106 }
107 
108 void xenvif_receive_skb(struct xenvif *vif, struct sk_buff *skb)
109 {
110 	netif_rx_ni(skb);
111 }
112 
113 void xenvif_notify_tx_completion(struct xenvif *vif)
114 {
115 	if (netif_queue_stopped(vif->dev) && xenvif_rx_schedulable(vif))
116 		netif_wake_queue(vif->dev);
117 }
118 
119 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
120 {
121 	struct xenvif *vif = netdev_priv(dev);
122 	return &vif->dev->stats;
123 }
124 
125 static void xenvif_up(struct xenvif *vif)
126 {
127 	xen_netbk_add_xenvif(vif);
128 	enable_irq(vif->irq);
129 	xen_netbk_check_rx_xenvif(vif);
130 }
131 
132 static void xenvif_down(struct xenvif *vif)
133 {
134 	disable_irq(vif->irq);
135 	xen_netbk_deschedule_xenvif(vif);
136 	xen_netbk_remove_xenvif(vif);
137 }
138 
139 static int xenvif_open(struct net_device *dev)
140 {
141 	struct xenvif *vif = netdev_priv(dev);
142 	if (netif_carrier_ok(dev))
143 		xenvif_up(vif);
144 	netif_start_queue(dev);
145 	return 0;
146 }
147 
148 static int xenvif_close(struct net_device *dev)
149 {
150 	struct xenvif *vif = netdev_priv(dev);
151 	if (netif_carrier_ok(dev))
152 		xenvif_down(vif);
153 	netif_stop_queue(dev);
154 	return 0;
155 }
156 
157 static int xenvif_change_mtu(struct net_device *dev, int mtu)
158 {
159 	struct xenvif *vif = netdev_priv(dev);
160 	int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
161 
162 	if (mtu > max)
163 		return -EINVAL;
164 	dev->mtu = mtu;
165 	return 0;
166 }
167 
168 static void xenvif_set_features(struct xenvif *vif)
169 {
170 	struct net_device *dev = vif->dev;
171 	u32 features = dev->features;
172 
173 	if (vif->can_sg)
174 		features |= NETIF_F_SG;
175 	if (vif->gso || vif->gso_prefix)
176 		features |= NETIF_F_TSO;
177 	if (vif->csum)
178 		features |= NETIF_F_IP_CSUM;
179 
180 	features &= ~(vif->features_disabled);
181 
182 	if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN)
183 		dev->mtu = ETH_DATA_LEN;
184 
185 	dev->features = features;
186 }
187 
188 static int xenvif_set_tx_csum(struct net_device *dev, u32 data)
189 {
190 	struct xenvif *vif = netdev_priv(dev);
191 	if (data) {
192 		if (!vif->csum)
193 			return -EOPNOTSUPP;
194 		vif->features_disabled &= ~NETIF_F_IP_CSUM;
195 	} else {
196 		vif->features_disabled |= NETIF_F_IP_CSUM;
197 	}
198 
199 	xenvif_set_features(vif);
200 	return 0;
201 }
202 
203 static int xenvif_set_sg(struct net_device *dev, u32 data)
204 {
205 	struct xenvif *vif = netdev_priv(dev);
206 	if (data) {
207 		if (!vif->can_sg)
208 			return -EOPNOTSUPP;
209 		vif->features_disabled &= ~NETIF_F_SG;
210 	} else {
211 		vif->features_disabled |= NETIF_F_SG;
212 	}
213 
214 	xenvif_set_features(vif);
215 	return 0;
216 }
217 
218 static int xenvif_set_tso(struct net_device *dev, u32 data)
219 {
220 	struct xenvif *vif = netdev_priv(dev);
221 	if (data) {
222 		if (!vif->gso && !vif->gso_prefix)
223 			return -EOPNOTSUPP;
224 		vif->features_disabled &= ~NETIF_F_TSO;
225 	} else {
226 		vif->features_disabled |= NETIF_F_TSO;
227 	}
228 
229 	xenvif_set_features(vif);
230 	return 0;
231 }
232 
233 static const struct xenvif_stat {
234 	char name[ETH_GSTRING_LEN];
235 	u16 offset;
236 } xenvif_stats[] = {
237 	{
238 		"rx_gso_checksum_fixup",
239 		offsetof(struct xenvif, rx_gso_checksum_fixup)
240 	},
241 };
242 
243 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
244 {
245 	switch (string_set) {
246 	case ETH_SS_STATS:
247 		return ARRAY_SIZE(xenvif_stats);
248 	default:
249 		return -EINVAL;
250 	}
251 }
252 
253 static void xenvif_get_ethtool_stats(struct net_device *dev,
254 				     struct ethtool_stats *stats, u64 * data)
255 {
256 	void *vif = netdev_priv(dev);
257 	int i;
258 
259 	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
260 		data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
261 }
262 
263 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
264 {
265 	int i;
266 
267 	switch (stringset) {
268 	case ETH_SS_STATS:
269 		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
270 			memcpy(data + i * ETH_GSTRING_LEN,
271 			       xenvif_stats[i].name, ETH_GSTRING_LEN);
272 		break;
273 	}
274 }
275 
276 static struct ethtool_ops xenvif_ethtool_ops = {
277 	.get_tx_csum	= ethtool_op_get_tx_csum,
278 	.set_tx_csum	= xenvif_set_tx_csum,
279 	.get_sg		= ethtool_op_get_sg,
280 	.set_sg		= xenvif_set_sg,
281 	.get_tso	= ethtool_op_get_tso,
282 	.set_tso	= xenvif_set_tso,
283 	.get_link	= ethtool_op_get_link,
284 
285 	.get_sset_count = xenvif_get_sset_count,
286 	.get_ethtool_stats = xenvif_get_ethtool_stats,
287 	.get_strings = xenvif_get_strings,
288 };
289 
290 static struct net_device_ops xenvif_netdev_ops = {
291 	.ndo_start_xmit	= xenvif_start_xmit,
292 	.ndo_get_stats	= xenvif_get_stats,
293 	.ndo_open	= xenvif_open,
294 	.ndo_stop	= xenvif_close,
295 	.ndo_change_mtu	= xenvif_change_mtu,
296 };
297 
298 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
299 			    unsigned int handle)
300 {
301 	int err;
302 	struct net_device *dev;
303 	struct xenvif *vif;
304 	char name[IFNAMSIZ] = {};
305 
306 	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
307 	dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
308 	if (dev == NULL) {
309 		pr_warn("Could not allocate netdev\n");
310 		return ERR_PTR(-ENOMEM);
311 	}
312 
313 	SET_NETDEV_DEV(dev, parent);
314 
315 	vif = netdev_priv(dev);
316 	vif->domid  = domid;
317 	vif->handle = handle;
318 	vif->netbk  = NULL;
319 	vif->can_sg = 1;
320 	vif->csum = 1;
321 	atomic_set(&vif->refcnt, 1);
322 	init_waitqueue_head(&vif->waiting_to_free);
323 	vif->dev = dev;
324 	INIT_LIST_HEAD(&vif->schedule_list);
325 	INIT_LIST_HEAD(&vif->notify_list);
326 
327 	vif->credit_bytes = vif->remaining_credit = ~0UL;
328 	vif->credit_usec  = 0UL;
329 	init_timer(&vif->credit_timeout);
330 	/* Initialize 'expires' now: it's used to track the credit window. */
331 	vif->credit_timeout.expires = jiffies;
332 
333 	dev->netdev_ops	= &xenvif_netdev_ops;
334 	xenvif_set_features(vif);
335 	SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
336 
337 	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
338 
339 	/*
340 	 * Initialise a dummy MAC address. We choose the numerically
341 	 * largest non-broadcast address to prevent the address getting
342 	 * stolen by an Ethernet bridge for STP purposes.
343 	 * (FE:FF:FF:FF:FF:FF)
344 	 */
345 	memset(dev->dev_addr, 0xFF, ETH_ALEN);
346 	dev->dev_addr[0] &= ~0x01;
347 
348 	netif_carrier_off(dev);
349 
350 	err = register_netdev(dev);
351 	if (err) {
352 		netdev_warn(dev, "Could not register device: err=%d\n", err);
353 		free_netdev(dev);
354 		return ERR_PTR(err);
355 	}
356 
357 	netdev_dbg(dev, "Successfully created xenvif\n");
358 	return vif;
359 }
360 
361 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
362 		   unsigned long rx_ring_ref, unsigned int evtchn)
363 {
364 	int err = -ENOMEM;
365 
366 	/* Already connected through? */
367 	if (vif->irq)
368 		return 0;
369 
370 	xenvif_set_features(vif);
371 
372 	err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
373 	if (err < 0)
374 		goto err;
375 
376 	err = bind_interdomain_evtchn_to_irqhandler(
377 		vif->domid, evtchn, xenvif_interrupt, 0,
378 		vif->dev->name, vif);
379 	if (err < 0)
380 		goto err_unmap;
381 	vif->irq = err;
382 	disable_irq(vif->irq);
383 
384 	xenvif_get(vif);
385 
386 	rtnl_lock();
387 	netif_carrier_on(vif->dev);
388 	if (netif_running(vif->dev))
389 		xenvif_up(vif);
390 	rtnl_unlock();
391 
392 	return 0;
393 err_unmap:
394 	xen_netbk_unmap_frontend_rings(vif);
395 err:
396 	return err;
397 }
398 
399 void xenvif_disconnect(struct xenvif *vif)
400 {
401 	struct net_device *dev = vif->dev;
402 	if (netif_carrier_ok(dev)) {
403 		rtnl_lock();
404 		netif_carrier_off(dev); /* discard queued packets */
405 		if (netif_running(dev))
406 			xenvif_down(vif);
407 		rtnl_unlock();
408 		xenvif_put(vif);
409 	}
410 
411 	atomic_dec(&vif->refcnt);
412 	wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
413 
414 	del_timer_sync(&vif->credit_timeout);
415 
416 	if (vif->irq)
417 		unbind_from_irqhandler(vif->irq, vif);
418 
419 	unregister_netdev(vif->dev);
420 
421 	xen_netbk_unmap_frontend_rings(vif);
422 
423 	free_netdev(vif->dev);
424 }
425