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
42void xenvif_get(struct xenvif *vif)
43{
44	atomic_inc(&vif->refcnt);
45}
46
47void xenvif_put(struct xenvif *vif)
48{
49	if (atomic_dec_and_test(&vif->refcnt))
50		wake_up(&vif->waiting_to_free);
51}
52
53int xenvif_schedulable(struct xenvif *vif)
54{
55	return netif_running(vif->dev) && netif_carrier_ok(vif->dev);
56}
57
58static int xenvif_rx_schedulable(struct xenvif *vif)
59{
60	return xenvif_schedulable(vif) && !xen_netbk_rx_ring_full(vif);
61}
62
63static 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
78static 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
108void xenvif_receive_skb(struct xenvif *vif, struct sk_buff *skb)
109{
110	netif_rx_ni(skb);
111}
112
113void 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
119static 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
125static 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
132static 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
139static 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
148static 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
157static 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
168static netdev_features_t xenvif_fix_features(struct net_device *dev,
169	netdev_features_t features)
170{
171	struct xenvif *vif = netdev_priv(dev);
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	return features;
181}
182
183static const struct xenvif_stat {
184	char name[ETH_GSTRING_LEN];
185	u16 offset;
186} xenvif_stats[] = {
187	{
188		"rx_gso_checksum_fixup",
189		offsetof(struct xenvif, rx_gso_checksum_fixup)
190	},
191};
192
193static int xenvif_get_sset_count(struct net_device *dev, int string_set)
194{
195	switch (string_set) {
196	case ETH_SS_STATS:
197		return ARRAY_SIZE(xenvif_stats);
198	default:
199		return -EINVAL;
200	}
201}
202
203static void xenvif_get_ethtool_stats(struct net_device *dev,
204				     struct ethtool_stats *stats, u64 * data)
205{
206	void *vif = netdev_priv(dev);
207	int i;
208
209	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
210		data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
211}
212
213static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
214{
215	int i;
216
217	switch (stringset) {
218	case ETH_SS_STATS:
219		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
220			memcpy(data + i * ETH_GSTRING_LEN,
221			       xenvif_stats[i].name, ETH_GSTRING_LEN);
222		break;
223	}
224}
225
226static const struct ethtool_ops xenvif_ethtool_ops = {
227	.get_link	= ethtool_op_get_link,
228
229	.get_sset_count = xenvif_get_sset_count,
230	.get_ethtool_stats = xenvif_get_ethtool_stats,
231	.get_strings = xenvif_get_strings,
232};
233
234static const struct net_device_ops xenvif_netdev_ops = {
235	.ndo_start_xmit	= xenvif_start_xmit,
236	.ndo_get_stats	= xenvif_get_stats,
237	.ndo_open	= xenvif_open,
238	.ndo_stop	= xenvif_close,
239	.ndo_change_mtu	= xenvif_change_mtu,
240	.ndo_fix_features = xenvif_fix_features,
241};
242
243struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
244			    unsigned int handle)
245{
246	int err;
247	struct net_device *dev;
248	struct xenvif *vif;
249	char name[IFNAMSIZ] = {};
250
251	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
252	dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
253	if (dev == NULL) {
254		pr_warn("Could not allocate netdev\n");
255		return ERR_PTR(-ENOMEM);
256	}
257
258	SET_NETDEV_DEV(dev, parent);
259
260	vif = netdev_priv(dev);
261	vif->domid  = domid;
262	vif->handle = handle;
263	vif->netbk  = NULL;
264	vif->can_sg = 1;
265	vif->csum = 1;
266	atomic_set(&vif->refcnt, 1);
267	init_waitqueue_head(&vif->waiting_to_free);
268	vif->dev = dev;
269	INIT_LIST_HEAD(&vif->schedule_list);
270	INIT_LIST_HEAD(&vif->notify_list);
271
272	vif->credit_bytes = vif->remaining_credit = ~0UL;
273	vif->credit_usec  = 0UL;
274	init_timer(&vif->credit_timeout);
275	/* Initialize 'expires' now: it's used to track the credit window. */
276	vif->credit_timeout.expires = jiffies;
277
278	dev->netdev_ops	= &xenvif_netdev_ops;
279	dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
280	dev->features = dev->hw_features;
281	SET_ETHTOOL_OPS(dev, &xenvif_ethtool_ops);
282
283	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
284
285	/*
286	 * Initialise a dummy MAC address. We choose the numerically
287	 * largest non-broadcast address to prevent the address getting
288	 * stolen by an Ethernet bridge for STP purposes.
289	 * (FE:FF:FF:FF:FF:FF)
290	 */
291	memset(dev->dev_addr, 0xFF, ETH_ALEN);
292	dev->dev_addr[0] &= ~0x01;
293
294	netif_carrier_off(dev);
295
296	err = register_netdev(dev);
297	if (err) {
298		netdev_warn(dev, "Could not register device: err=%d\n", err);
299		free_netdev(dev);
300		return ERR_PTR(err);
301	}
302
303	netdev_dbg(dev, "Successfully created xenvif\n");
304	return vif;
305}
306
307int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
308		   unsigned long rx_ring_ref, unsigned int evtchn)
309{
310	int err = -ENOMEM;
311
312	/* Already connected through? */
313	if (vif->irq)
314		return 0;
315
316	err = xen_netbk_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
317	if (err < 0)
318		goto err;
319
320	err = bind_interdomain_evtchn_to_irqhandler(
321		vif->domid, evtchn, xenvif_interrupt, 0,
322		vif->dev->name, vif);
323	if (err < 0)
324		goto err_unmap;
325	vif->irq = err;
326	disable_irq(vif->irq);
327
328	xenvif_get(vif);
329
330	rtnl_lock();
331	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
332		dev_set_mtu(vif->dev, ETH_DATA_LEN);
333	netdev_update_features(vif->dev);
334	netif_carrier_on(vif->dev);
335	if (netif_running(vif->dev))
336		xenvif_up(vif);
337	rtnl_unlock();
338
339	return 0;
340err_unmap:
341	xen_netbk_unmap_frontend_rings(vif);
342err:
343	return err;
344}
345
346void xenvif_disconnect(struct xenvif *vif)
347{
348	struct net_device *dev = vif->dev;
349	if (netif_carrier_ok(dev)) {
350		rtnl_lock();
351		netif_carrier_off(dev); /* discard queued packets */
352		if (netif_running(dev))
353			xenvif_down(vif);
354		rtnl_unlock();
355		xenvif_put(vif);
356	}
357
358	atomic_dec(&vif->refcnt);
359	wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0);
360
361	del_timer_sync(&vif->credit_timeout);
362
363	if (vif->irq)
364		unbind_from_irqhandler(vif->irq, vif);
365
366	unregister_netdev(vif->dev);
367
368	xen_netbk_unmap_frontend_rings(vif);
369
370	free_netdev(vif->dev);
371}
372