aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/lguest_net.c
blob: 112778652f7d8986345a439ab5e7f46815af1369 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
/* A simple network driver for lguest.
 *
 * Copyright 2006 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
 *
 * 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
 */
//#define DEBUG
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/module.h>
#include <linux/mm_types.h>
#include <linux/io.h>
#include <linux/lguest_bus.h>

#define SHARED_SIZE		PAGE_SIZE
#define MAX_LANS		4
#define NUM_SKBS		8

struct lguestnet_info
{
	/* The shared page(s). */
	struct lguest_net *peer;
	unsigned long peer_phys;
	unsigned long mapsize;

	/* The lguest_device I come from */
	struct lguest_device *lgdev;

	/* My peerid. */
	unsigned int me;

	/* Receive queue. */
	struct sk_buff *skb[NUM_SKBS];
	struct lguest_dma dma[NUM_SKBS];
};

/* How many bytes left in this page. */
static unsigned int rest_of_page(void *data)
{
	return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE);
}

/* Simple convention: offset 4 * peernum. */
static unsigned long peer_key(struct lguestnet_info *info, unsigned peernum)
{
	return info->peer_phys + 4 * peernum;
}

static void skb_to_dma(const struct sk_buff *skb, unsigned int headlen,
		       struct lguest_dma *dma)
{
	unsigned int i, seg;

	for (i = seg = 0; i < headlen; seg++, i += rest_of_page(skb->data+i)) {
		dma->addr[seg] = virt_to_phys(skb->data + i);
		dma->len[seg] = min((unsigned)(headlen - i),
				    rest_of_page(skb->data + i));
	}
	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++, seg++) {
		const skb_frag_t *f = &skb_shinfo(skb)->frags[i];
		/* Should not happen with MTU less than 64k - 2 * PAGE_SIZE. */
		if (seg == LGUEST_MAX_DMA_SECTIONS) {
			printk("Woah dude!  Megapacket!\n");
			break;
		}
		dma->addr[seg] = page_to_phys(f->page) + f->page_offset;
		dma->len[seg] = f->size;
	}
	if (seg < LGUEST_MAX_DMA_SECTIONS)
		dma->len[seg] = 0;
}

/* We overload multicast bit to show promiscuous mode. */
#define PROMISC_BIT		0x01

static void lguestnet_set_multicast(struct net_device *dev)
{
	struct lguestnet_info *info = netdev_priv(dev);

	if ((dev->flags & (IFF_PROMISC|IFF_ALLMULTI)) || dev->mc_count)
		info->peer[info->me].mac[0] |= PROMISC_BIT;
	else
		info->peer[info->me].mac[0] &= ~PROMISC_BIT;
}

static int promisc(struct lguestnet_info *info, unsigned int peer)
{
	return info->peer[peer].mac[0] & PROMISC_BIT;
}

static int mac_eq(const unsigned char mac[ETH_ALEN],
		  struct lguestnet_info *info, unsigned int peer)
{
	/* Ignore multicast bit, which peer turns on to mean promisc. */
	if ((info->peer[peer].mac[0] & (~PROMISC_BIT)) != mac[0])
		return 0;
	return memcmp(mac+1, info->peer[peer].mac+1, ETH_ALEN-1) == 0;
}

static void transfer_packet(struct net_device *dev,
			    struct sk_buff *skb,
			    unsigned int peernum)
{
	struct lguestnet_info *info = netdev_priv(dev);
	struct lguest_dma dma;

	skb_to_dma(skb, skb_headlen(skb), &dma);
	pr_debug("xfer length %04x (%u)\n", htons(skb->len), skb->len);

	lguest_send_dma(peer_key(info, peernum), &dma);
	if (dma.used_len != skb->len) {
		dev->stats.tx_carrier_errors++;
		pr_debug("Bad xfer to peer %i: %i of %i (dma %p/%i)\n",
			 peernum, dma.used_len, skb->len,
			 (void *)dma.addr[0], dma.len[0]);
	} else {
		dev->stats.tx_bytes += skb->len;
		dev->stats.tx_packets++;
	}
}

static int unused_peer(const struct lguest_net peer[], unsigned int num)
{
	return peer[num].mac[0] == 0;
}

static int lguestnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	unsigned int i;
	int broadcast;
	struct lguestnet_info *info = netdev_priv(dev);
	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;

	pr_debug("%s: xmit %02x:%02x:%02x:%02x:%02x:%02x\n",
		 dev->name, dest[0],dest[1],dest[2],dest[3],dest[4],dest[5]);

	broadcast = is_multicast_ether_addr(dest);
	for (i = 0; i < info->mapsize/sizeof(struct lguest_net); i++) {
		if (i == info->me || unused_peer(info->peer, i))
			continue;

		if (!broadcast && !promisc(info, i) && !mac_eq(dest, info, i))
			continue;

		pr_debug("lguestnet %s: sending from %i to %i\n",
			 dev->name, info->me, i);
		transfer_packet(dev, skb, i);
	}
	dev_kfree_skb(skb);
	return 0;
}

/* Find a new skb to put in this slot in shared mem. */
static int fill_slot(struct net_device *dev, unsigned int slot)
{
	struct lguestnet_info *info = netdev_priv(dev);
	/* Try to create and register a new one. */
	info->skb[slot] = netdev_alloc_skb(dev, ETH_HLEN + ETH_DATA_LEN);
	if (!info->skb[slot]) {
		printk("%s: could not fill slot %i\n", dev->name, slot);
		return -ENOMEM;
	}

	skb_to_dma(info->skb[slot], ETH_HLEN + ETH_DATA_LEN, &info->dma[slot]);
	wmb();
	/* Now we tell hypervisor it can use the slot. */
	info->dma[slot].used_len = 0;
	return 0;
}

static irqreturn_t lguestnet_rcv(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct lguestnet_info *info = netdev_priv(dev);
	unsigned int i, done = 0;

	for (i = 0; i < ARRAY_SIZE(info->dma); i++) {
		unsigned int length;
		struct sk_buff *skb;

		length = info->dma[i].used_len;
		if (length == 0)
			continue;

		done++;
		skb = info->skb[i];
		fill_slot(dev, i);

		if (length < ETH_HLEN || length > ETH_HLEN + ETH_DATA_LEN) {
			pr_debug(KERN_WARNING "%s: unbelievable skb len: %i\n",
				 dev->name, length);
			dev_kfree_skb(skb);
			continue;
		}

		skb_put(skb, length);
		skb->protocol = eth_type_trans(skb, dev);
		/* This is a reliable transport. */
		if (dev->features & NETIF_F_NO_CSUM)
			skb->ip_summed = CHECKSUM_UNNECESSARY;
		pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
			 ntohs(skb->protocol), skb->len, skb->pkt_type);

		dev->stats.rx_bytes += skb->len;
		dev->stats.rx_packets++;
		netif_rx(skb);
	}
	return done ? IRQ_HANDLED : IRQ_NONE;
}

static int lguestnet_open(struct net_device *dev)
{
	int i;
	struct lguestnet_info *info = netdev_priv(dev);

	/* Set up our MAC address */
	memcpy(info->peer[info->me].mac, dev->dev_addr, ETH_ALEN);

	/* Turn on promisc mode if needed */
	lguestnet_set_multicast(dev);

	for (i = 0; i < ARRAY_SIZE(info->dma); i++) {
		if (fill_slot(dev, i) != 0)
			goto cleanup;
	}
	if (lguest_bind_dma(peer_key(info,info->me), info->dma,
			    NUM_SKBS, lgdev_irq(info->lgdev)) != 0)
		goto cleanup;
	return 0;

cleanup:
	while (--i >= 0)
		dev_kfree_skb(info->skb[i]);
	return -ENOMEM;
}

static int lguestnet_close(struct net_device *dev)
{
	unsigned int i;
	struct lguestnet_info *info = netdev_priv(dev);

	/* Clear all trace: others might deliver packets, we'll ignore it. */
	memset(&info->peer[info->me], 0, sizeof(info->peer[info->me]));

	/* Deregister sg lists. */
	lguest_unbind_dma(peer_key(info, info->me), info->dma);
	for (i = 0; i < ARRAY_SIZE(info->dma); i++)
		dev_kfree_skb(info->skb[i]);
	return 0;
}

static int lguestnet_probe(struct lguest_device *lgdev)
{
	int err, irqf = IRQF_SHARED;
	struct net_device *dev;
	struct lguestnet_info *info;
	struct lguest_device_desc *desc = &lguest_devices[lgdev->index];

	pr_debug("lguest_net: probing for device %i\n", lgdev->index);

	dev = alloc_etherdev(sizeof(struct lguestnet_info));
	if (!dev)
		return -ENOMEM;

	SET_MODULE_OWNER(dev);

	/* Ethernet defaults with some changes */
	ether_setup(dev);
	dev->set_mac_address = NULL;

	dev->dev_addr[0] = 0x02; /* set local assignment bit (IEEE802) */
	dev->dev_addr[1] = 0x00;
	memcpy(&dev->dev_addr[2], &lguest_data.guestid, 2);
	dev->dev_addr[4] = 0x00;
	dev->dev_addr[5] = 0x00;

	dev->open = lguestnet_open;
	dev->stop = lguestnet_close;
	dev->hard_start_xmit = lguestnet_start_xmit;

	/* Turning on/off promisc will call dev->set_multicast_list.
	 * We don't actually support multicast yet */
	dev->set_multicast_list = lguestnet_set_multicast;
	SET_NETDEV_DEV(dev, &lgdev->dev);
	if (desc->features & LGUEST_NET_F_NOCSUM)
		dev->features = NETIF_F_SG|NETIF_F_NO_CSUM;

	info = netdev_priv(dev);
	info->mapsize = PAGE_SIZE * desc->num_pages;
	info->peer_phys = ((unsigned long)desc->pfn << PAGE_SHIFT);
	info->lgdev = lgdev;
	info->peer = lguest_map(info->peer_phys, desc->num_pages);
	if (!info->peer) {
		err = -ENOMEM;
		goto free;
	}

	/* This stores our peerid (upper bits reserved for future). */
	info->me = (desc->features & (info->mapsize-1));

	err = register_netdev(dev);
	if (err) {
		pr_debug("lguestnet: registering device failed\n");
		goto unmap;
	}

	if (lguest_devices[lgdev->index].features & LGUEST_DEVICE_F_RANDOMNESS)
		irqf |= IRQF_SAMPLE_RANDOM;
	if (request_irq(lgdev_irq(lgdev), lguestnet_rcv, irqf, "lguestnet",
			dev) != 0) {
		pr_debug("lguestnet: cannot get irq %i\n", lgdev_irq(lgdev));
		goto unregister;
	}

	pr_debug("lguestnet: registered device %s\n", dev->name);
	lgdev->private = dev;
	return 0;

unregister:
	unregister_netdev(dev);
unmap:
	lguest_unmap(info->peer);
free:
	free_netdev(dev);
	return err;
}

static struct lguest_driver lguestnet_drv = {
	.name = "lguestnet",
	.owner = THIS_MODULE,
	.device_type = LGUEST_DEVICE_T_NET,
	.probe = lguestnet_probe,
};

static __init int lguestnet_init(void)
{
	return register_lguest_driver(&lguestnet_drv);
}
module_init(lguestnet_init);

MODULE_DESCRIPTION("Lguest network driver");
MODULE_LICENSE("GPL");