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 	del_timer_sync(&vif->credit_timeout);
136 	xen_netbk_deschedule_xenvif(vif);
137 	xen_netbk_remove_xenvif(vif);
138 }
139 
140 static int xenvif_open(struct net_device *dev)
141 {
142 	struct xenvif *vif = netdev_priv(dev);
143 	if (netif_carrier_ok(dev))
144 		xenvif_up(vif);
145 	netif_start_queue(dev);
146 	return 0;
147 }
148 
149 static int xenvif_close(struct net_device *dev)
150 {
151 	struct xenvif *vif = netdev_priv(dev);
152 	if (netif_carrier_ok(dev))
153 		xenvif_down(vif);
154 	netif_stop_queue(dev);
155 	return 0;
156 }
157 
158 static int xenvif_change_mtu(struct net_device *dev, int mtu)
159 {
160 	struct xenvif *vif = netdev_priv(dev);
161 	int max = vif->can_sg ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN;
162 
163 	if (mtu > max)
164 		return -EINVAL;
165 	dev->mtu = mtu;
166 	return 0;
167 }
168 
169 static netdev_features_t xenvif_fix_features(struct net_device *dev,
170 	netdev_features_t features)
171 {
172 	struct xenvif *vif = netdev_priv(dev);
173 
174 	if (!vif->can_sg)
175 		features &= ~NETIF_F_SG;
176 	if (!vif->gso && !vif->gso_prefix)
177 		features &= ~NETIF_F_TSO;
178 	if (!vif->csum)
179 		features &= ~NETIF_F_IP_CSUM;
180 
181 	return features;
182 }
183 
184 static const struct xenvif_stat {
185 	char name[ETH_GSTRING_LEN];
186 	u16 offset;
187 } xenvif_stats[] = {
188 	{
189 		"rx_gso_checksum_fixup",
190 		offsetof(struct xenvif, rx_gso_checksum_fixup)
191 	},
192 };
193 
194 static int xenvif_get_sset_count(struct net_device *dev, int string_set)
195 {
196 	switch (string_set) {
197 	case ETH_SS_STATS:
198 		return ARRAY_SIZE(xenvif_stats);
199 	default:
200 		return -EINVAL;
201 	}
202 }
203 
204 static void xenvif_get_ethtool_stats(struct net_device *dev,
205 				     struct ethtool_stats *stats, u64 * data)
206 {
207 	void *vif = netdev_priv(dev);
208 	int i;
209 
210 	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
211 		data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
212 }
213 
214 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
215 {
216 	int i;
217 
218 	switch (stringset) {
219 	case ETH_SS_STATS:
220 		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
221 			memcpy(data + i * ETH_GSTRING_LEN,
222 			       xenvif_stats[i].name, ETH_GSTRING_LEN);
223 		break;
224 	}
225 }
226 
227 static const struct ethtool_ops xenvif_ethtool_ops = {
228 	.get_link	= ethtool_op_get_link,
229 
230 	.get_sset_count = xenvif_get_sset_count,
231 	.get_ethtool_stats = xenvif_get_ethtool_stats,
232 	.get_strings = xenvif_get_strings,
233 };
234 
235 static const struct net_device_ops xenvif_netdev_ops = {
236 	.ndo_start_xmit	= xenvif_start_xmit,
237 	.ndo_get_stats	= xenvif_get_stats,
238 	.ndo_open	= xenvif_open,
239 	.ndo_stop	= xenvif_close,
240 	.ndo_change_mtu	= xenvif_change_mtu,
241 	.ndo_fix_features = xenvif_fix_features,
242 	.ndo_set_mac_address = eth_mac_addr,
243 	.ndo_validate_addr   = eth_validate_addr,
244 };
245 
246 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
247 			    unsigned int handle)
248 {
249 	int err;
250 	struct net_device *dev;
251 	struct xenvif *vif;
252 	char name[IFNAMSIZ] = {};
253 
254 	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
255 	dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
256 	if (dev == NULL) {
257 		pr_warn("Could not allocate netdev\n");
258 		return ERR_PTR(-ENOMEM);
259 	}
260 
261 	SET_NETDEV_DEV(dev, parent);
262 
263 	vif = netdev_priv(dev);
264 	vif->domid  = domid;
265 	vif->handle = handle;
266 	vif->netbk  = NULL;
267 	vif->can_sg = 1;
268 	vif->csum = 1;
269 	atomic_set(&vif->refcnt, 1);
270 	init_waitqueue_head(&vif->waiting_to_free);
271 	vif->dev = dev;
272 	INIT_LIST_HEAD(&vif->schedule_list);
273 	INIT_LIST_HEAD(&vif->notify_list);
274 
275 	vif->credit_bytes = vif->remaining_credit = ~0UL;
276 	vif->credit_usec  = 0UL;
277 	init_timer(&vif->credit_timeout);
278 	/* Initialize 'expires' now: it's used to track the credit window. */
279 	vif->credit_timeout.expires = jiffies;
280 
281 	dev->netdev_ops	= &xenvif_netdev_ops;
282 	dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
283 	dev->features = dev->hw_features;
284 	SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
285 
286 	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
287 
288 	/*
289 	 * Initialise a dummy MAC address. We choose the numerically
290 	 * largest non-broadcast address to prevent the address getting
291 	 * stolen by an Ethernet bridge for STP purposes.
292 	 * (FE:FF:FF:FF:FF:FF)
293 	 */
294 	memset(dev->dev_addr, 0xFF, ETH_ALEN);
295 	dev->dev_addr[0] &= ~0x01;
296 
297 	netif_carrier_off(dev);
298 
299 	err = register_netdev(dev);
300 	if (err) {
301 		netdev_warn(dev, "Could not register device: err=%d\n", err);
302 		free_netdev(dev);
303 		return ERR_PTR(err);
304 	}
305 
306 	netdev_dbg(dev, "Successfully created xenvif\n");
307 	return vif;
308 }
309 
310 int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
311 		   unsigned long rx_ring_ref, unsigned int evtchn)
312 {
313 	int err = -ENOMEM;
314 
315 	/* Already connected through? */
316 	if (vif->irq)
317 		return 0;
318 
319 	err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
320 	if (err < 0)
321 		goto err;
322 
323 	err = bind_interdomain_evtchn_to_irqhandler(
324 		vif->domid, evtchn, xenvif_interrupt, 0,
325 		vif->dev->name, vif);
326 	if (err < 0)
327 		goto err_unmap;
328 	vif->irq = err;
329 	disable_irq(vif->irq);
330 
331 	xenvif_get(vif);
332 
333 	rtnl_lock();
334 	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
335 		dev_set_mtu(vif->dev, ETH_DATA_LEN);
336 	netdev_update_features(vif->dev);
337 	netif_carrier_on(vif->dev);
338 	if (netif_running(vif->dev))
339 		xenvif_up(vif);
340 	rtnl_unlock();
341 
342 	return 0;
343 err_unmap:
344 	xen_netbk_unmap_frontend_rings(vif);
345 err:
346 	return err;
347 }
348 
349 void xenvif_carrier_off(struct xenvif *vif)
350 {
351 	struct net_device *dev = vif->dev;
352 
353 	rtnl_lock();
354 	netif_carrier_off(dev); /* discard queued packets */
355 	if (netif_running(dev))
356 		xenvif_down(vif);
357 	rtnl_unlock();
358 	xenvif_put(vif);
359 }
360 
361 void xenvif_disconnect(struct xenvif *vif)
362 {
363 	if (netif_carrier_ok(vif->dev))
364 		xenvif_carrier_off(vif);
365 
366 	atomic_dec(&vif->refcnt);
367 	wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
368 
369 	if (vif->irq)
370 		unbind_from_irqhandler(vif->irq, vif);
371 
372 	unregister_netdev(vif->dev);
373 
374 	xen_netbk_unmap_frontend_rings(vif);
375 
376 	free_netdev(vif->dev);
377 }
378