1 /* A simple network driver using virtio.
3 * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
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.
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.
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
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>
27 /* FIXME: MTU in config. */
28 #define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
32 struct virtio_device *vdev;
33 struct virtqueue *rvq, *svq;
34 struct net_device *dev;
35 struct napi_struct napi;
37 /* Number of input buffers, and max we've ever had. */
38 unsigned int num, max;
40 /* Receive & send queues. */
41 struct sk_buff_head recv;
42 struct sk_buff_head send;
45 static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
47 return (struct virtio_net_hdr *)skb->cb;
50 static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
52 sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
55 static bool skb_xmit_done(struct virtqueue *rvq)
57 struct virtnet_info *vi = rvq->vdev->priv;
59 /* In case we were waiting for output buffers. */
60 netif_wake_queue(vi->dev);
64 static void receive_skb(struct net_device *dev, struct sk_buff *skb,
67 struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
69 if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
70 pr_debug("%s: short packet %i\n", dev->name, len);
71 dev->stats.rx_length_errors++;
74 len -= sizeof(struct virtio_net_hdr);
75 BUG_ON(len > MAX_PACKET_LEN);
78 skb->protocol = eth_type_trans(skb, dev);
79 pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
80 ntohs(skb->protocol), skb->len, skb->pkt_type);
81 dev->stats.rx_bytes += skb->len;
82 dev->stats.rx_packets++;
84 if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
85 pr_debug("Needs csum!\n");
86 if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
90 if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
92 switch (hdr->gso_type) {
93 case VIRTIO_NET_HDR_GSO_TCPV4:
94 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
96 case VIRTIO_NET_HDR_GSO_TCPV4_ECN:
97 skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN;
99 case VIRTIO_NET_HDR_GSO_UDP:
100 skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
102 case VIRTIO_NET_HDR_GSO_TCPV6:
103 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
107 printk(KERN_WARNING "%s: bad gso type %u.\n",
108 dev->name, hdr->gso_type);
112 skb_shinfo(skb)->gso_size = hdr->gso_size;
113 if (skb_shinfo(skb)->gso_size == 0) {
115 printk(KERN_WARNING "%s: zero gso size.\n",
120 /* Header must be checked, and gso_segs computed. */
121 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
122 skb_shinfo(skb)->gso_segs = 0;
125 netif_receive_skb(skb);
129 dev->stats.rx_frame_errors++;
134 static void try_fill_recv(struct virtnet_info *vi)
137 struct scatterlist sg[1+MAX_SKB_FRAGS];
140 sg_init_table(sg, 1+MAX_SKB_FRAGS);
142 skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
146 skb_put(skb, MAX_PACKET_LEN);
147 vnet_hdr_to_sg(sg, skb);
148 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
149 skb_queue_head(&vi->recv, skb);
151 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
153 skb_unlink(skb, &vi->recv);
159 if (unlikely(vi->num > vi->max))
161 vi->rvq->vq_ops->kick(vi->rvq);
164 static bool skb_recv_done(struct virtqueue *rvq)
166 struct virtnet_info *vi = rvq->vdev->priv;
167 netif_rx_schedule(vi->dev, &vi->napi);
168 /* Suppress further interrupts. */
172 static int virtnet_poll(struct napi_struct *napi, int budget)
174 struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
175 struct sk_buff *skb = NULL;
176 unsigned int len, received = 0;
179 while (received < budget &&
180 (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
181 __skb_unlink(skb, &vi->recv);
182 receive_skb(vi->dev, skb, len);
187 /* FIXME: If we oom and completely run out of inbufs, we need
188 * to start a timer trying to fill more. */
189 if (vi->num < vi->max / 2)
192 /* Out of packets? */
193 if (received < budget) {
194 netif_rx_complete(vi->dev, napi);
195 if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq))
196 && netif_rx_reschedule(vi->dev, napi))
203 static void free_old_xmit_skbs(struct virtnet_info *vi)
208 while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
209 pr_debug("Sent skb %p\n", skb);
210 __skb_unlink(skb, &vi->send);
211 vi->dev->stats.tx_bytes += len;
212 vi->dev->stats.tx_packets++;
217 static int start_xmit(struct sk_buff *skb, struct net_device *dev)
219 struct virtnet_info *vi = netdev_priv(dev);
221 struct scatterlist sg[1+MAX_SKB_FRAGS];
222 struct virtio_net_hdr *hdr;
223 const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
224 DECLARE_MAC_BUF(mac);
226 sg_init_table(sg, 1+MAX_SKB_FRAGS);
228 pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
230 free_old_xmit_skbs(vi);
232 /* Encode metadata header at front. */
233 hdr = skb_vnet_hdr(skb);
234 if (skb->ip_summed == CHECKSUM_PARTIAL) {
235 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
236 hdr->csum_start = skb->csum_start - skb_headroom(skb);
237 hdr->csum_offset = skb->csum_offset;
240 hdr->csum_offset = hdr->csum_start = 0;
243 if (skb_is_gso(skb)) {
244 hdr->gso_size = skb_shinfo(skb)->gso_size;
245 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
246 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN;
247 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
248 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
249 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
250 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
251 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
252 hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
256 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
260 vnet_hdr_to_sg(sg, skb);
261 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
262 __skb_queue_head(&vi->send, skb);
263 err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
265 pr_debug("%s: virtio not prepared to send\n", dev->name);
266 skb_unlink(skb, &vi->send);
267 netif_stop_queue(dev);
268 return NETDEV_TX_BUSY;
270 vi->svq->vq_ops->kick(vi->svq);
275 static int virtnet_open(struct net_device *dev)
277 struct virtnet_info *vi = netdev_priv(dev);
281 /* If we didn't even get one input buffer, we're useless. */
285 napi_enable(&vi->napi);
289 static int virtnet_close(struct net_device *dev)
291 struct virtnet_info *vi = netdev_priv(dev);
294 napi_disable(&vi->napi);
296 /* networking core has neutered skb_xmit_done/skb_recv_done, so don't
297 * worry about races vs. get(). */
298 vi->rvq->vq_ops->shutdown(vi->rvq);
299 while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
303 vi->svq->vq_ops->shutdown(vi->svq);
304 while ((skb = __skb_dequeue(&vi->send)) != NULL)
307 BUG_ON(vi->num != 0);
311 static int virtnet_probe(struct virtio_device *vdev)
314 struct net_device *dev;
315 struct virtnet_info *vi;
317 /* Allocate ourselves a network device with room for our info */
318 dev = alloc_etherdev(sizeof(struct virtnet_info));
322 /* Set up network device as normal. */
324 dev->open = virtnet_open;
325 dev->stop = virtnet_close;
326 dev->hard_start_xmit = start_xmit;
327 dev->features = NETIF_F_HIGHDMA;
328 SET_NETDEV_DEV(dev, &vdev->dev);
330 /* Do we support "hardware" checksums? */
331 if (vdev->config->feature(vdev, VIRTIO_NET_F_NO_CSUM)) {
332 /* This opens up the world of extra features. */
333 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
334 if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4))
335 dev->features |= NETIF_F_TSO;
336 if (vdev->config->feature(vdev, VIRTIO_NET_F_UFO))
337 dev->features |= NETIF_F_UFO;
338 if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4_ECN))
339 dev->features |= NETIF_F_TSO_ECN;
340 if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO6))
341 dev->features |= NETIF_F_TSO6;
344 /* Configuration may specify what MAC to use. Otherwise random. */
345 if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
346 vdev->config->get(vdev,
347 offsetof(struct virtio_net_config, mac),
348 dev->dev_addr, dev->addr_len);
350 random_ether_addr(dev->dev_addr);
352 /* Set up our device-specific information */
353 vi = netdev_priv(dev);
354 netif_napi_add(dev, &vi->napi, virtnet_poll, 16);
358 /* We expect two virtqueues, receive then send. */
359 vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
360 if (IS_ERR(vi->rvq)) {
361 err = PTR_ERR(vi->rvq);
365 vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
366 if (IS_ERR(vi->svq)) {
367 err = PTR_ERR(vi->svq);
371 /* Initialize our empty receive and send queues. */
372 skb_queue_head_init(&vi->recv);
373 skb_queue_head_init(&vi->send);
375 err = register_netdev(dev);
377 pr_debug("virtio_net: registering device failed\n");
380 pr_debug("virtnet: registered device %s\n", dev->name);
385 vdev->config->del_vq(vi->svq);
387 vdev->config->del_vq(vi->rvq);
393 static void virtnet_remove(struct virtio_device *vdev)
395 struct virtnet_info *vi = vdev->priv;
397 vdev->config->del_vq(vi->svq);
398 vdev->config->del_vq(vi->rvq);
399 unregister_netdev(vi->dev);
400 free_netdev(vi->dev);
403 static struct virtio_device_id id_table[] = {
404 { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
408 static struct virtio_driver virtio_net = {
409 .driver.name = KBUILD_MODNAME,
410 .driver.owner = THIS_MODULE,
411 .id_table = id_table,
412 .probe = virtnet_probe,
413 .remove = __devexit_p(virtnet_remove),
416 static int __init init(void)
418 return register_virtio_driver(&virtio_net);
421 static void __exit fini(void)
423 unregister_virtio_driver(&virtio_net);
428 MODULE_DEVICE_TABLE(virtio, id_table);
429 MODULE_DESCRIPTION("Virtio network driver");
430 MODULE_LICENSE("GPL");