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296f96fc RR |
1 | /* A simple network driver using virtio. |
2 | * | |
3 | * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, write to the Free Software | |
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
18 | */ | |
19 | //#define DEBUG | |
20 | #include <linux/netdevice.h> | |
21 | #include <linux/etherdevice.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/virtio.h> | |
24 | #include <linux/virtio_net.h> | |
25 | #include <linux/scatterlist.h> | |
26 | ||
27 | /* FIXME: MTU in config. */ | |
28 | #define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN) | |
29 | ||
30 | struct virtnet_info | |
31 | { | |
32 | struct virtio_device *vdev; | |
33 | struct virtqueue *rvq, *svq; | |
34 | struct net_device *dev; | |
35 | struct napi_struct napi; | |
36 | ||
37 | /* Number of input buffers, and max we've ever had. */ | |
38 | unsigned int num, max; | |
39 | ||
40 | /* Receive & send queues. */ | |
41 | struct sk_buff_head recv; | |
42 | struct sk_buff_head send; | |
43 | }; | |
44 | ||
45 | static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb) | |
46 | { | |
47 | return (struct virtio_net_hdr *)skb->cb; | |
48 | } | |
49 | ||
50 | static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb) | |
51 | { | |
52 | sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr)); | |
53 | } | |
54 | ||
18445c4d | 55 | static void skb_xmit_done(struct virtqueue *rvq) |
296f96fc RR |
56 | { |
57 | struct virtnet_info *vi = rvq->vdev->priv; | |
58 | ||
59 | /* In case we were waiting for output buffers. */ | |
60 | netif_wake_queue(vi->dev); | |
296f96fc RR |
61 | } |
62 | ||
63 | static void receive_skb(struct net_device *dev, struct sk_buff *skb, | |
64 | unsigned len) | |
65 | { | |
66 | struct virtio_net_hdr *hdr = skb_vnet_hdr(skb); | |
67 | ||
68 | if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) { | |
69 | pr_debug("%s: short packet %i\n", dev->name, len); | |
70 | dev->stats.rx_length_errors++; | |
71 | goto drop; | |
72 | } | |
73 | len -= sizeof(struct virtio_net_hdr); | |
74 | BUG_ON(len > MAX_PACKET_LEN); | |
75 | ||
76 | skb_trim(skb, len); | |
77 | skb->protocol = eth_type_trans(skb, dev); | |
78 | pr_debug("Receiving skb proto 0x%04x len %i type %i\n", | |
79 | ntohs(skb->protocol), skb->len, skb->pkt_type); | |
80 | dev->stats.rx_bytes += skb->len; | |
81 | dev->stats.rx_packets++; | |
82 | ||
83 | if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { | |
84 | pr_debug("Needs csum!\n"); | |
f35d9d8a | 85 | if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset)) |
296f96fc | 86 | goto frame_err; |
296f96fc RR |
87 | } |
88 | ||
89 | if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { | |
90 | pr_debug("GSO!\n"); | |
91 | switch (hdr->gso_type) { | |
92 | case VIRTIO_NET_HDR_GSO_TCPV4: | |
93 | skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; | |
94 | break; | |
95 | case VIRTIO_NET_HDR_GSO_TCPV4_ECN: | |
96 | skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN; | |
97 | break; | |
98 | case VIRTIO_NET_HDR_GSO_UDP: | |
99 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; | |
100 | break; | |
101 | case VIRTIO_NET_HDR_GSO_TCPV6: | |
102 | skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; | |
103 | break; | |
104 | default: | |
105 | if (net_ratelimit()) | |
106 | printk(KERN_WARNING "%s: bad gso type %u.\n", | |
107 | dev->name, hdr->gso_type); | |
108 | goto frame_err; | |
109 | } | |
110 | ||
111 | skb_shinfo(skb)->gso_size = hdr->gso_size; | |
112 | if (skb_shinfo(skb)->gso_size == 0) { | |
113 | if (net_ratelimit()) | |
114 | printk(KERN_WARNING "%s: zero gso size.\n", | |
115 | dev->name); | |
116 | goto frame_err; | |
117 | } | |
118 | ||
119 | /* Header must be checked, and gso_segs computed. */ | |
120 | skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; | |
121 | skb_shinfo(skb)->gso_segs = 0; | |
122 | } | |
123 | ||
124 | netif_receive_skb(skb); | |
125 | return; | |
126 | ||
127 | frame_err: | |
128 | dev->stats.rx_frame_errors++; | |
129 | drop: | |
130 | dev_kfree_skb(skb); | |
131 | } | |
132 | ||
133 | static void try_fill_recv(struct virtnet_info *vi) | |
134 | { | |
135 | struct sk_buff *skb; | |
136 | struct scatterlist sg[1+MAX_SKB_FRAGS]; | |
137 | int num, err; | |
138 | ||
4d125de3 | 139 | sg_init_table(sg, 1+MAX_SKB_FRAGS); |
296f96fc RR |
140 | for (;;) { |
141 | skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN); | |
142 | if (unlikely(!skb)) | |
143 | break; | |
144 | ||
145 | skb_put(skb, MAX_PACKET_LEN); | |
146 | vnet_hdr_to_sg(sg, skb); | |
147 | num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; | |
148 | skb_queue_head(&vi->recv, skb); | |
149 | ||
150 | err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb); | |
151 | if (err) { | |
152 | skb_unlink(skb, &vi->recv); | |
153 | kfree_skb(skb); | |
154 | break; | |
155 | } | |
156 | vi->num++; | |
157 | } | |
158 | if (unlikely(vi->num > vi->max)) | |
159 | vi->max = vi->num; | |
160 | vi->rvq->vq_ops->kick(vi->rvq); | |
161 | } | |
162 | ||
18445c4d | 163 | static void skb_recv_done(struct virtqueue *rvq) |
296f96fc RR |
164 | { |
165 | struct virtnet_info *vi = rvq->vdev->priv; | |
18445c4d RR |
166 | /* Schedule NAPI, Suppress further interrupts if successful. */ |
167 | if (netif_rx_schedule_prep(vi->dev, &vi->napi)) { | |
168 | rvq->vq_ops->disable_cb(rvq); | |
169 | __netif_rx_schedule(vi->dev, &vi->napi); | |
170 | } | |
296f96fc RR |
171 | } |
172 | ||
173 | static int virtnet_poll(struct napi_struct *napi, int budget) | |
174 | { | |
175 | struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi); | |
176 | struct sk_buff *skb = NULL; | |
177 | unsigned int len, received = 0; | |
178 | ||
179 | again: | |
180 | while (received < budget && | |
181 | (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) { | |
182 | __skb_unlink(skb, &vi->recv); | |
183 | receive_skb(vi->dev, skb, len); | |
184 | vi->num--; | |
185 | received++; | |
186 | } | |
187 | ||
188 | /* FIXME: If we oom and completely run out of inbufs, we need | |
189 | * to start a timer trying to fill more. */ | |
190 | if (vi->num < vi->max / 2) | |
191 | try_fill_recv(vi); | |
192 | ||
8329d98e RR |
193 | /* Out of packets? */ |
194 | if (received < budget) { | |
296f96fc | 195 | netif_rx_complete(vi->dev, napi); |
18445c4d | 196 | if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq)) |
296f96fc RR |
197 | && netif_rx_reschedule(vi->dev, napi)) |
198 | goto again; | |
199 | } | |
200 | ||
201 | return received; | |
202 | } | |
203 | ||
204 | static void free_old_xmit_skbs(struct virtnet_info *vi) | |
205 | { | |
206 | struct sk_buff *skb; | |
207 | unsigned int len; | |
208 | ||
209 | while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) { | |
210 | pr_debug("Sent skb %p\n", skb); | |
211 | __skb_unlink(skb, &vi->send); | |
212 | vi->dev->stats.tx_bytes += len; | |
213 | vi->dev->stats.tx_packets++; | |
214 | kfree_skb(skb); | |
215 | } | |
216 | } | |
217 | ||
218 | static int start_xmit(struct sk_buff *skb, struct net_device *dev) | |
219 | { | |
220 | struct virtnet_info *vi = netdev_priv(dev); | |
221 | int num, err; | |
222 | struct scatterlist sg[1+MAX_SKB_FRAGS]; | |
223 | struct virtio_net_hdr *hdr; | |
224 | const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; | |
225 | DECLARE_MAC_BUF(mac); | |
226 | ||
4d125de3 RR |
227 | sg_init_table(sg, 1+MAX_SKB_FRAGS); |
228 | ||
296f96fc RR |
229 | pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest)); |
230 | ||
231 | free_old_xmit_skbs(vi); | |
232 | ||
233 | /* Encode metadata header at front. */ | |
234 | hdr = skb_vnet_hdr(skb); | |
235 | if (skb->ip_summed == CHECKSUM_PARTIAL) { | |
236 | hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; | |
237 | hdr->csum_start = skb->csum_start - skb_headroom(skb); | |
238 | hdr->csum_offset = skb->csum_offset; | |
239 | } else { | |
240 | hdr->flags = 0; | |
241 | hdr->csum_offset = hdr->csum_start = 0; | |
242 | } | |
243 | ||
244 | if (skb_is_gso(skb)) { | |
245 | hdr->gso_size = skb_shinfo(skb)->gso_size; | |
246 | if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN) | |
247 | hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN; | |
248 | else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) | |
249 | hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; | |
250 | else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) | |
251 | hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; | |
252 | else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) | |
253 | hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; | |
254 | else | |
255 | BUG(); | |
256 | } else { | |
257 | hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; | |
258 | hdr->gso_size = 0; | |
259 | } | |
260 | ||
261 | vnet_hdr_to_sg(sg, skb); | |
262 | num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; | |
263 | __skb_queue_head(&vi->send, skb); | |
264 | err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb); | |
265 | if (err) { | |
266 | pr_debug("%s: virtio not prepared to send\n", dev->name); | |
267 | skb_unlink(skb, &vi->send); | |
268 | netif_stop_queue(dev); | |
269 | return NETDEV_TX_BUSY; | |
270 | } | |
271 | vi->svq->vq_ops->kick(vi->svq); | |
272 | ||
273 | return 0; | |
274 | } | |
275 | ||
276 | static int virtnet_open(struct net_device *dev) | |
277 | { | |
278 | struct virtnet_info *vi = netdev_priv(dev); | |
279 | ||
280 | try_fill_recv(vi); | |
281 | ||
282 | /* If we didn't even get one input buffer, we're useless. */ | |
283 | if (vi->num == 0) | |
284 | return -ENOMEM; | |
285 | ||
286 | napi_enable(&vi->napi); | |
287 | return 0; | |
288 | } | |
289 | ||
290 | static int virtnet_close(struct net_device *dev) | |
291 | { | |
292 | struct virtnet_info *vi = netdev_priv(dev); | |
293 | struct sk_buff *skb; | |
294 | ||
295 | napi_disable(&vi->napi); | |
296 | ||
297 | /* networking core has neutered skb_xmit_done/skb_recv_done, so don't | |
298 | * worry about races vs. get(). */ | |
299 | vi->rvq->vq_ops->shutdown(vi->rvq); | |
300 | while ((skb = __skb_dequeue(&vi->recv)) != NULL) { | |
301 | kfree_skb(skb); | |
302 | vi->num--; | |
303 | } | |
304 | vi->svq->vq_ops->shutdown(vi->svq); | |
305 | while ((skb = __skb_dequeue(&vi->send)) != NULL) | |
306 | kfree_skb(skb); | |
307 | ||
308 | BUG_ON(vi->num != 0); | |
309 | return 0; | |
310 | } | |
311 | ||
312 | static int virtnet_probe(struct virtio_device *vdev) | |
313 | { | |
314 | int err; | |
296f96fc RR |
315 | struct net_device *dev; |
316 | struct virtnet_info *vi; | |
296f96fc RR |
317 | |
318 | /* Allocate ourselves a network device with room for our info */ | |
319 | dev = alloc_etherdev(sizeof(struct virtnet_info)); | |
320 | if (!dev) | |
321 | return -ENOMEM; | |
322 | ||
323 | /* Set up network device as normal. */ | |
324 | ether_setup(dev); | |
325 | dev->open = virtnet_open; | |
326 | dev->stop = virtnet_close; | |
327 | dev->hard_start_xmit = start_xmit; | |
328 | dev->features = NETIF_F_HIGHDMA; | |
329 | SET_NETDEV_DEV(dev, &vdev->dev); | |
330 | ||
331 | /* Do we support "hardware" checksums? */ | |
a586d4f6 | 332 | if (vdev->config->feature(vdev, VIRTIO_NET_F_NO_CSUM)) { |
296f96fc RR |
333 | /* This opens up the world of extra features. */ |
334 | dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST; | |
a586d4f6 | 335 | if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4)) |
296f96fc | 336 | dev->features |= NETIF_F_TSO; |
a586d4f6 | 337 | if (vdev->config->feature(vdev, VIRTIO_NET_F_UFO)) |
296f96fc | 338 | dev->features |= NETIF_F_UFO; |
a586d4f6 | 339 | if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4_ECN)) |
296f96fc | 340 | dev->features |= NETIF_F_TSO_ECN; |
a586d4f6 | 341 | if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO6)) |
296f96fc RR |
342 | dev->features |= NETIF_F_TSO6; |
343 | } | |
344 | ||
345 | /* Configuration may specify what MAC to use. Otherwise random. */ | |
a586d4f6 RR |
346 | if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) { |
347 | vdev->config->get(vdev, | |
348 | offsetof(struct virtio_net_config, mac), | |
349 | dev->dev_addr, dev->addr_len); | |
296f96fc RR |
350 | } else |
351 | random_ether_addr(dev->dev_addr); | |
352 | ||
353 | /* Set up our device-specific information */ | |
354 | vi = netdev_priv(dev); | |
355 | netif_napi_add(dev, &vi->napi, virtnet_poll, 16); | |
356 | vi->dev = dev; | |
357 | vi->vdev = vdev; | |
358 | ||
359 | /* We expect two virtqueues, receive then send. */ | |
a586d4f6 | 360 | vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done); |
296f96fc RR |
361 | if (IS_ERR(vi->rvq)) { |
362 | err = PTR_ERR(vi->rvq); | |
363 | goto free; | |
364 | } | |
365 | ||
a586d4f6 | 366 | vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done); |
296f96fc RR |
367 | if (IS_ERR(vi->svq)) { |
368 | err = PTR_ERR(vi->svq); | |
369 | goto free_recv; | |
370 | } | |
371 | ||
372 | /* Initialize our empty receive and send queues. */ | |
373 | skb_queue_head_init(&vi->recv); | |
374 | skb_queue_head_init(&vi->send); | |
375 | ||
376 | err = register_netdev(dev); | |
377 | if (err) { | |
378 | pr_debug("virtio_net: registering device failed\n"); | |
379 | goto free_send; | |
380 | } | |
381 | pr_debug("virtnet: registered device %s\n", dev->name); | |
382 | vdev->priv = vi; | |
383 | return 0; | |
384 | ||
385 | free_send: | |
386 | vdev->config->del_vq(vi->svq); | |
387 | free_recv: | |
388 | vdev->config->del_vq(vi->rvq); | |
389 | free: | |
390 | free_netdev(dev); | |
391 | return err; | |
392 | } | |
393 | ||
394 | static void virtnet_remove(struct virtio_device *vdev) | |
395 | { | |
74b2553f RR |
396 | struct virtnet_info *vi = vdev->priv; |
397 | ||
398 | vdev->config->del_vq(vi->svq); | |
399 | vdev->config->del_vq(vi->rvq); | |
400 | unregister_netdev(vi->dev); | |
401 | free_netdev(vi->dev); | |
296f96fc RR |
402 | } |
403 | ||
404 | static struct virtio_device_id id_table[] = { | |
405 | { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID }, | |
406 | { 0 }, | |
407 | }; | |
408 | ||
409 | static struct virtio_driver virtio_net = { | |
410 | .driver.name = KBUILD_MODNAME, | |
411 | .driver.owner = THIS_MODULE, | |
412 | .id_table = id_table, | |
413 | .probe = virtnet_probe, | |
414 | .remove = __devexit_p(virtnet_remove), | |
415 | }; | |
416 | ||
417 | static int __init init(void) | |
418 | { | |
419 | return register_virtio_driver(&virtio_net); | |
420 | } | |
421 | ||
422 | static void __exit fini(void) | |
423 | { | |
424 | unregister_virtio_driver(&virtio_net); | |
425 | } | |
426 | module_init(init); | |
427 | module_exit(fini); | |
428 | ||
429 | MODULE_DEVICE_TABLE(virtio, id_table); | |
430 | MODULE_DESCRIPTION("Virtio network driver"); | |
431 | MODULE_LICENSE("GPL"); |