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_tx_interrupt(int irq, void *dev_id)
64 {
65 	struct xenvif *vif = dev_id;
66 
67 	if (vif->netbk == NULL)
68 		return IRQ_HANDLED;
69 
70 	xen_netbk_schedule_xenvif(vif);
71 
72 	return IRQ_HANDLED;
73 }
74 
75 static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
76 {
77 	struct xenvif *vif = dev_id;
78 
79 	if (vif->netbk == NULL)
80 		return IRQ_HANDLED;
81 
82 	if (xenvif_rx_schedulable(vif))
83 		netif_wake_queue(vif->dev);
84 
85 	return IRQ_HANDLED;
86 }
87 
88 static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
89 {
90 	xenvif_tx_interrupt(irq, dev_id);
91 	xenvif_rx_interrupt(irq, dev_id);
92 
93 	return IRQ_HANDLED;
94 }
95 
96 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
97 {
98 	struct xenvif *vif = netdev_priv(dev);
99 
100 	BUG_ON(skb->dev != dev);
101 
102 	if (vif->netbk == NULL)
103 		goto drop;
104 
105 	/* Drop the packet if the target domain has no receive buffers. */
106 	if (!xenvif_rx_schedulable(vif))
107 		goto drop;
108 
109 	/* Reserve ring slots for the worst-case number of fragments. */
110 	vif->rx_req_cons_peek += xen_netbk_count_skb_slots(vif, skb);
111 	xenvif_get(vif);
112 
113 	if (vif->can_queue && xen_netbk_must_stop_queue(vif))
114 		netif_stop_queue(dev);
115 
116 	xen_netbk_queue_tx_skb(vif, skb);
117 
118 	return NETDEV_TX_OK;
119 
120  drop:
121 	vif->dev->stats.tx_dropped++;
122 	dev_kfree_skb(skb);
123 	return NETDEV_TX_OK;
124 }
125 
126 void xenvif_receive_skb(struct xenvif *vif, struct sk_buff *skb)
127 {
128 	netif_rx_ni(skb);
129 }
130 
131 void xenvif_notify_tx_completion(struct xenvif *vif)
132 {
133 	if (netif_queue_stopped(vif->dev) && xenvif_rx_schedulable(vif))
134 		netif_wake_queue(vif->dev);
135 }
136 
137 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
138 {
139 	struct xenvif *vif = netdev_priv(dev);
140 	return &vif->dev->stats;
141 }
142 
143 static void xenvif_up(struct xenvif *vif)
144 {
145 	xen_netbk_add_xenvif(vif);
146 	enable_irq(vif->tx_irq);
147 	if (vif->tx_irq != vif->rx_irq)
148 		enable_irq(vif->rx_irq);
149 	xen_netbk_check_rx_xenvif(vif);
150 }
151 
152 static void xenvif_down(struct xenvif *vif)
153 {
154 	disable_irq(vif->tx_irq);
155 	if (vif->tx_irq != vif->rx_irq)
156 		disable_irq(vif->rx_irq);
157 	del_timer_sync(&vif->credit_timeout);
158 	xen_netbk_deschedule_xenvif(vif);
159 	xen_netbk_remove_xenvif(vif);
160 }
161 
162 static int xenvif_open(struct net_device *dev)
163 {
164 	struct xenvif *vif = netdev_priv(dev);
165 	if (netif_carrier_ok(dev))
166 		xenvif_up(vif);
167 	netif_start_queue(dev);
168 	return 0;
169 }
170 
171 static int xenvif_close(struct net_device *dev)
172 {
173 	struct xenvif *vif = netdev_priv(dev);
174 	if (netif_carrier_ok(dev))
175 		xenvif_down(vif);
176 	netif_stop_queue(dev);
177 	return 0;
178 }
179 
180 static int xenvif_change_mtu(struct net_device *dev, int mtu)
181 {
182 	struct xenvif *vif = netdev_priv(dev);
183 	int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
184 
185 	if (mtu > max)
186 		return -EINVAL;
187 	dev->mtu = mtu;
188 	return 0;
189 }
190 
191 static netdev_features_t xenvif_fix_features(struct net_device *dev,
192 	netdev_features_t features)
193 {
194 	struct xenvif *vif = netdev_priv(dev);
195 
196 	if (!vif->can_sg)
197 		features &= ~NETIF_F_SG;
198 	if (!vif->gso && !vif->gso_prefix)
199 		features &= ~NETIF_F_TSO;
200 	if (!vif->csum)
201 		features &= ~NETIF_F_IP_CSUM;
202 
203 	return features;
204 }
205 
206 static const struct xenvif_stat {
207 	char name[ETH_GSTRING_LEN];
208 	u16 offset;
209 } xenvif_stats[] = {
210 	{
211 		"rx_gso_checksum_fixup",
212 		offsetof(struct xenvif, rx_gso_checksum_fixup)
213 	},
214 };
215 
216 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
217 {
218 	switch (string_set) {
219 	case ETH_SS_STATS:
220 		return ARRAY_SIZE(xenvif_stats);
221 	default:
222 		return -EINVAL;
223 	}
224 }
225 
226 static void xenvif_get_ethtool_stats(struct net_device *dev,
227 				     struct ethtool_stats *stats, u64 * data)
228 {
229 	void *vif = netdev_priv(dev);
230 	int i;
231 
232 	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
233 		data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
234 }
235 
236 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
237 {
238 	int i;
239 
240 	switch (stringset) {
241 	case ETH_SS_STATS:
242 		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
243 			memcpy(data + i * ETH_GSTRING_LEN,
244 			       xenvif_stats[i].name, ETH_GSTRING_LEN);
245 		break;
246 	}
247 }
248 
249 static const struct ethtool_ops xenvif_ethtool_ops = {
250 	.get_link	= ethtool_op_get_link,
251 
252 	.get_sset_count = xenvif_get_sset_count,
253 	.get_ethtool_stats = xenvif_get_ethtool_stats,
254 	.get_strings = xenvif_get_strings,
255 };
256 
257 static const struct net_device_ops xenvif_netdev_ops = {
258 	.ndo_start_xmit	= xenvif_start_xmit,
259 	.ndo_get_stats	= xenvif_get_stats,
260 	.ndo_open	= xenvif_open,
261 	.ndo_stop	= xenvif_close,
262 	.ndo_change_mtu	= xenvif_change_mtu,
263 	.ndo_fix_features = xenvif_fix_features,
264 	.ndo_set_mac_address = eth_mac_addr,
265 	.ndo_validate_addr   = eth_validate_addr,
266 };
267 
268 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
269 			    unsigned int handle)
270 {
271 	int err;
272 	struct net_device *dev;
273 	struct xenvif *vif;
274 	char name[IFNAMSIZ] = {};
275 
276 	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
277 	dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
278 	if (dev == NULL) {
279 		pr_warn("Could not allocate netdev\n");
280 		return ERR_PTR(-ENOMEM);
281 	}
282 
283 	SET_NETDEV_DEV(dev, parent);
284 
285 	vif = netdev_priv(dev);
286 	vif->domid  = domid;
287 	vif->handle = handle;
288 	vif->netbk  = NULL;
289 	vif->can_sg = 1;
290 	vif->csum = 1;
291 	atomic_set(&vif->refcnt, 1);
292 	init_waitqueue_head(&vif->waiting_to_free);
293 	vif->dev = dev;
294 	INIT_LIST_HEAD(&vif->schedule_list);
295 	INIT_LIST_HEAD(&vif->notify_list);
296 
297 	vif->credit_bytes = vif->remaining_credit = ~0UL;
298 	vif->credit_usec  = 0UL;
299 	init_timer(&vif->credit_timeout);
300 	/* Initialize 'expires' now: it's used to track the credit window. */
301 	vif->credit_timeout.expires = jiffies;
302 
303 	dev->netdev_ops	= &xenvif_netdev_ops;
304 	dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
305 	dev->features = dev->hw_features;
306 	SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
307 
308 	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
309 
310 	/*
311 	 * Initialise a dummy MAC address. We choose the numerically
312 	 * largest non-broadcast address to prevent the address getting
313 	 * stolen by an Ethernet bridge for STP purposes.
314 	 * (FE:FF:FF:FF:FF:FF)
315 	 */
316 	memset(dev->dev_addr, 0xFF, ETH_ALEN);
317 	dev->dev_addr[0] &= ~0x01;
318 
319 	netif_carrier_off(dev);
320 
321 	err = register_netdev(dev);
322 	if (err) {
323 		netdev_warn(dev, "Could not register device: err=%d\n", err);
324 		free_netdev(dev);
325 		return ERR_PTR(err);
326 	}
327 
328 	netdev_dbg(dev, "Successfully created xenvif\n");
329 	return vif;
330 }
331 
332 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
333 		   unsigned long rx_ring_ref, unsigned int tx_evtchn,
334 		   unsigned int rx_evtchn)
335 {
336 	int err = -ENOMEM;
337 
338 	/* Already connected through? */
339 	if (vif->tx_irq)
340 		return 0;
341 
342 	__module_get(THIS_MODULE);
343 
344 	err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
345 	if (err < 0)
346 		goto err;
347 
348 	if (tx_evtchn == rx_evtchn) {
349 		/* feature-split-event-channels == 0 */
350 		err = bind_interdomain_evtchn_to_irqhandler(
351 			vif->domid, tx_evtchn, xenvif_interrupt, 0,
352 			vif->dev->name, vif);
353 		if (err < 0)
354 			goto err_unmap;
355 		vif->tx_irq = vif->rx_irq = err;
356 		disable_irq(vif->tx_irq);
357 	} else {
358 		/* feature-split-event-channels == 1 */
359 		snprintf(vif->tx_irq_name, sizeof(vif->tx_irq_name),
360 			 "%s-tx", vif->dev->name);
361 		err = bind_interdomain_evtchn_to_irqhandler(
362 			vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
363 			vif->tx_irq_name, vif);
364 		if (err < 0)
365 			goto err_unmap;
366 		vif->tx_irq = err;
367 		disable_irq(vif->tx_irq);
368 
369 		snprintf(vif->rx_irq_name, sizeof(vif->rx_irq_name),
370 			 "%s-rx", vif->dev->name);
371 		err = bind_interdomain_evtchn_to_irqhandler(
372 			vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
373 			vif->rx_irq_name, vif);
374 		if (err < 0)
375 			goto err_tx_unbind;
376 		vif->rx_irq = err;
377 		disable_irq(vif->rx_irq);
378 	}
379 
380 	xenvif_get(vif);
381 
382 	rtnl_lock();
383 	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
384 		dev_set_mtu(vif->dev, ETH_DATA_LEN);
385 	netdev_update_features(vif->dev);
386 	netif_carrier_on(vif->dev);
387 	if (netif_running(vif->dev))
388 		xenvif_up(vif);
389 	rtnl_unlock();
390 
391 	return 0;
392 err_tx_unbind:
393 	unbind_from_irqhandler(vif->tx_irq, vif);
394 	vif->tx_irq = 0;
395 err_unmap:
396 	xen_netbk_unmap_frontend_rings(vif);
397 err:
398 	module_put(THIS_MODULE);
399 	return err;
400 }
401 
402 void xenvif_carrier_off(struct xenvif *vif)
403 {
404 	struct net_device *dev = vif->dev;
405 
406 	rtnl_lock();
407 	netif_carrier_off(dev); /* discard queued packets */
408 	if (netif_running(dev))
409 		xenvif_down(vif);
410 	rtnl_unlock();
411 	xenvif_put(vif);
412 }
413 
414 void xenvif_disconnect(struct xenvif *vif)
415 {
416 	/* Disconnect funtion might get called by generic framework
417 	 * even before vif connects, so we need to check if we really
418 	 * need to do a module_put.
419 	 */
420 	int need_module_put = 0;
421 
422 	if (netif_carrier_ok(vif->dev))
423 		xenvif_carrier_off(vif);
424 
425 	atomic_dec(&vif->refcnt);
426 	wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
427 
428 	if (vif->tx_irq) {
429 		if (vif->tx_irq == vif->rx_irq)
430 			unbind_from_irqhandler(vif->tx_irq, vif);
431 		else {
432 			unbind_from_irqhandler(vif->tx_irq, vif);
433 			unbind_from_irqhandler(vif->rx_irq, vif);
434 		}
435 		/* vif->irq is valid, we had a module_get in
436 		 * xenvif_connect.
437 		 */
438 		need_module_put = 1;
439 	}
440 
441 	unregister_netdev(vif->dev);
442 
443 	xen_netbk_unmap_frontend_rings(vif);
444 
445 	free_netdev(vif->dev);
446 
447 	if (need_module_put)
448 		module_put(THIS_MODULE);
449 }
450