Rusty Russell | 296f96f | 2007-10-22 11:03:37 +1000 | [diff] [blame] | 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 | |
| 55 | static bool skb_xmit_done(struct virtqueue *rvq) |
| 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); |
| 61 | return true; |
| 62 | } |
| 63 | |
| 64 | static void receive_skb(struct net_device *dev, struct sk_buff *skb, |
| 65 | unsigned len) |
| 66 | { |
| 67 | struct virtio_net_hdr *hdr = skb_vnet_hdr(skb); |
| 68 | |
| 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++; |
| 72 | goto drop; |
| 73 | } |
| 74 | len -= sizeof(struct virtio_net_hdr); |
| 75 | BUG_ON(len > MAX_PACKET_LEN); |
| 76 | |
| 77 | skb_trim(skb, 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++; |
| 83 | |
| 84 | if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { |
| 85 | pr_debug("Needs csum!\n"); |
| 86 | skb->ip_summed = CHECKSUM_PARTIAL; |
| 87 | skb->csum_start = hdr->csum_start; |
| 88 | skb->csum_offset = hdr->csum_offset; |
| 89 | if (skb->csum_start > skb->len - 2 |
| 90 | || skb->csum_offset > skb->len - 2) { |
| 91 | if (net_ratelimit()) |
| 92 | printk(KERN_WARNING "%s: csum=%u/%u len=%u\n", |
| 93 | dev->name, skb->csum_start, |
| 94 | skb->csum_offset, skb->len); |
| 95 | goto frame_err; |
| 96 | } |
| 97 | } |
| 98 | |
| 99 | if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { |
| 100 | pr_debug("GSO!\n"); |
| 101 | switch (hdr->gso_type) { |
| 102 | case VIRTIO_NET_HDR_GSO_TCPV4: |
| 103 | skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; |
| 104 | break; |
| 105 | case VIRTIO_NET_HDR_GSO_TCPV4_ECN: |
| 106 | skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN; |
| 107 | break; |
| 108 | case VIRTIO_NET_HDR_GSO_UDP: |
| 109 | skb_shinfo(skb)->gso_type = SKB_GSO_UDP; |
| 110 | break; |
| 111 | case VIRTIO_NET_HDR_GSO_TCPV6: |
| 112 | skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; |
| 113 | break; |
| 114 | default: |
| 115 | if (net_ratelimit()) |
| 116 | printk(KERN_WARNING "%s: bad gso type %u.\n", |
| 117 | dev->name, hdr->gso_type); |
| 118 | goto frame_err; |
| 119 | } |
| 120 | |
| 121 | skb_shinfo(skb)->gso_size = hdr->gso_size; |
| 122 | if (skb_shinfo(skb)->gso_size == 0) { |
| 123 | if (net_ratelimit()) |
| 124 | printk(KERN_WARNING "%s: zero gso size.\n", |
| 125 | dev->name); |
| 126 | goto frame_err; |
| 127 | } |
| 128 | |
| 129 | /* Header must be checked, and gso_segs computed. */ |
| 130 | skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; |
| 131 | skb_shinfo(skb)->gso_segs = 0; |
| 132 | } |
| 133 | |
| 134 | netif_receive_skb(skb); |
| 135 | return; |
| 136 | |
| 137 | frame_err: |
| 138 | dev->stats.rx_frame_errors++; |
| 139 | drop: |
| 140 | dev_kfree_skb(skb); |
| 141 | } |
| 142 | |
| 143 | static void try_fill_recv(struct virtnet_info *vi) |
| 144 | { |
| 145 | struct sk_buff *skb; |
| 146 | struct scatterlist sg[1+MAX_SKB_FRAGS]; |
| 147 | int num, err; |
| 148 | |
| 149 | for (;;) { |
| 150 | skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN); |
| 151 | if (unlikely(!skb)) |
| 152 | break; |
| 153 | |
| 154 | skb_put(skb, MAX_PACKET_LEN); |
| 155 | vnet_hdr_to_sg(sg, skb); |
| 156 | num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; |
| 157 | skb_queue_head(&vi->recv, skb); |
| 158 | |
| 159 | err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb); |
| 160 | if (err) { |
| 161 | skb_unlink(skb, &vi->recv); |
| 162 | kfree_skb(skb); |
| 163 | break; |
| 164 | } |
| 165 | vi->num++; |
| 166 | } |
| 167 | if (unlikely(vi->num > vi->max)) |
| 168 | vi->max = vi->num; |
| 169 | vi->rvq->vq_ops->kick(vi->rvq); |
| 170 | } |
| 171 | |
| 172 | static bool skb_recv_done(struct virtqueue *rvq) |
| 173 | { |
| 174 | struct virtnet_info *vi = rvq->vdev->priv; |
| 175 | netif_rx_schedule(vi->dev, &vi->napi); |
| 176 | /* Suppress further interrupts. */ |
| 177 | return false; |
| 178 | } |
| 179 | |
| 180 | static int virtnet_poll(struct napi_struct *napi, int budget) |
| 181 | { |
| 182 | struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi); |
| 183 | struct sk_buff *skb = NULL; |
| 184 | unsigned int len, received = 0; |
| 185 | |
| 186 | again: |
| 187 | while (received < budget && |
| 188 | (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) { |
| 189 | __skb_unlink(skb, &vi->recv); |
| 190 | receive_skb(vi->dev, skb, len); |
| 191 | vi->num--; |
| 192 | received++; |
| 193 | } |
| 194 | |
| 195 | /* FIXME: If we oom and completely run out of inbufs, we need |
| 196 | * to start a timer trying to fill more. */ |
| 197 | if (vi->num < vi->max / 2) |
| 198 | try_fill_recv(vi); |
| 199 | |
| 200 | /* All done? */ |
| 201 | if (!skb) { |
| 202 | netif_rx_complete(vi->dev, napi); |
| 203 | if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq)) |
| 204 | && netif_rx_reschedule(vi->dev, napi)) |
| 205 | goto again; |
| 206 | } |
| 207 | |
| 208 | return received; |
| 209 | } |
| 210 | |
| 211 | static void free_old_xmit_skbs(struct virtnet_info *vi) |
| 212 | { |
| 213 | struct sk_buff *skb; |
| 214 | unsigned int len; |
| 215 | |
| 216 | while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) { |
| 217 | pr_debug("Sent skb %p\n", skb); |
| 218 | __skb_unlink(skb, &vi->send); |
| 219 | vi->dev->stats.tx_bytes += len; |
| 220 | vi->dev->stats.tx_packets++; |
| 221 | kfree_skb(skb); |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | static int start_xmit(struct sk_buff *skb, struct net_device *dev) |
| 226 | { |
| 227 | struct virtnet_info *vi = netdev_priv(dev); |
| 228 | int num, err; |
| 229 | struct scatterlist sg[1+MAX_SKB_FRAGS]; |
| 230 | struct virtio_net_hdr *hdr; |
| 231 | const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; |
| 232 | DECLARE_MAC_BUF(mac); |
| 233 | |
| 234 | pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest)); |
| 235 | |
| 236 | free_old_xmit_skbs(vi); |
| 237 | |
| 238 | /* Encode metadata header at front. */ |
| 239 | hdr = skb_vnet_hdr(skb); |
| 240 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
| 241 | hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; |
| 242 | hdr->csum_start = skb->csum_start - skb_headroom(skb); |
| 243 | hdr->csum_offset = skb->csum_offset; |
| 244 | } else { |
| 245 | hdr->flags = 0; |
| 246 | hdr->csum_offset = hdr->csum_start = 0; |
| 247 | } |
| 248 | |
| 249 | if (skb_is_gso(skb)) { |
| 250 | hdr->gso_size = skb_shinfo(skb)->gso_size; |
| 251 | if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN) |
| 252 | hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN; |
| 253 | else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) |
| 254 | hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; |
| 255 | else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) |
| 256 | hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; |
| 257 | else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) |
| 258 | hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; |
| 259 | else |
| 260 | BUG(); |
| 261 | } else { |
| 262 | hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; |
| 263 | hdr->gso_size = 0; |
| 264 | } |
| 265 | |
| 266 | vnet_hdr_to_sg(sg, skb); |
| 267 | num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; |
| 268 | __skb_queue_head(&vi->send, skb); |
| 269 | err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb); |
| 270 | if (err) { |
| 271 | pr_debug("%s: virtio not prepared to send\n", dev->name); |
| 272 | skb_unlink(skb, &vi->send); |
| 273 | netif_stop_queue(dev); |
| 274 | return NETDEV_TX_BUSY; |
| 275 | } |
| 276 | vi->svq->vq_ops->kick(vi->svq); |
| 277 | |
| 278 | return 0; |
| 279 | } |
| 280 | |
| 281 | static int virtnet_open(struct net_device *dev) |
| 282 | { |
| 283 | struct virtnet_info *vi = netdev_priv(dev); |
| 284 | |
| 285 | try_fill_recv(vi); |
| 286 | |
| 287 | /* If we didn't even get one input buffer, we're useless. */ |
| 288 | if (vi->num == 0) |
| 289 | return -ENOMEM; |
| 290 | |
| 291 | napi_enable(&vi->napi); |
| 292 | return 0; |
| 293 | } |
| 294 | |
| 295 | static int virtnet_close(struct net_device *dev) |
| 296 | { |
| 297 | struct virtnet_info *vi = netdev_priv(dev); |
| 298 | struct sk_buff *skb; |
| 299 | |
| 300 | napi_disable(&vi->napi); |
| 301 | |
| 302 | /* networking core has neutered skb_xmit_done/skb_recv_done, so don't |
| 303 | * worry about races vs. get(). */ |
| 304 | vi->rvq->vq_ops->shutdown(vi->rvq); |
| 305 | while ((skb = __skb_dequeue(&vi->recv)) != NULL) { |
| 306 | kfree_skb(skb); |
| 307 | vi->num--; |
| 308 | } |
| 309 | vi->svq->vq_ops->shutdown(vi->svq); |
| 310 | while ((skb = __skb_dequeue(&vi->send)) != NULL) |
| 311 | kfree_skb(skb); |
| 312 | |
| 313 | BUG_ON(vi->num != 0); |
| 314 | return 0; |
| 315 | } |
| 316 | |
| 317 | static int virtnet_probe(struct virtio_device *vdev) |
| 318 | { |
| 319 | int err; |
| 320 | unsigned int len; |
| 321 | struct net_device *dev; |
| 322 | struct virtnet_info *vi; |
| 323 | void *token; |
| 324 | |
| 325 | /* Allocate ourselves a network device with room for our info */ |
| 326 | dev = alloc_etherdev(sizeof(struct virtnet_info)); |
| 327 | if (!dev) |
| 328 | return -ENOMEM; |
| 329 | |
| 330 | /* Set up network device as normal. */ |
| 331 | ether_setup(dev); |
| 332 | dev->open = virtnet_open; |
| 333 | dev->stop = virtnet_close; |
| 334 | dev->hard_start_xmit = start_xmit; |
| 335 | dev->features = NETIF_F_HIGHDMA; |
| 336 | SET_NETDEV_DEV(dev, &vdev->dev); |
| 337 | |
| 338 | /* Do we support "hardware" checksums? */ |
| 339 | token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len); |
| 340 | if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) { |
| 341 | /* This opens up the world of extra features. */ |
| 342 | dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST; |
| 343 | if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4)) |
| 344 | dev->features |= NETIF_F_TSO; |
| 345 | if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO)) |
| 346 | dev->features |= NETIF_F_UFO; |
| 347 | if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN)) |
| 348 | dev->features |= NETIF_F_TSO_ECN; |
| 349 | if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6)) |
| 350 | dev->features |= NETIF_F_TSO6; |
| 351 | } |
| 352 | |
| 353 | /* Configuration may specify what MAC to use. Otherwise random. */ |
| 354 | token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len); |
| 355 | if (token) { |
| 356 | dev->addr_len = len; |
| 357 | vdev->config->get(vdev, token, dev->dev_addr, len); |
| 358 | } else |
| 359 | random_ether_addr(dev->dev_addr); |
| 360 | |
| 361 | /* Set up our device-specific information */ |
| 362 | vi = netdev_priv(dev); |
| 363 | netif_napi_add(dev, &vi->napi, virtnet_poll, 16); |
| 364 | vi->dev = dev; |
| 365 | vi->vdev = vdev; |
| 366 | |
| 367 | /* We expect two virtqueues, receive then send. */ |
| 368 | vi->rvq = vdev->config->find_vq(vdev, skb_recv_done); |
| 369 | if (IS_ERR(vi->rvq)) { |
| 370 | err = PTR_ERR(vi->rvq); |
| 371 | goto free; |
| 372 | } |
| 373 | |
| 374 | vi->svq = vdev->config->find_vq(vdev, skb_xmit_done); |
| 375 | if (IS_ERR(vi->svq)) { |
| 376 | err = PTR_ERR(vi->svq); |
| 377 | goto free_recv; |
| 378 | } |
| 379 | |
| 380 | /* Initialize our empty receive and send queues. */ |
| 381 | skb_queue_head_init(&vi->recv); |
| 382 | skb_queue_head_init(&vi->send); |
| 383 | |
| 384 | err = register_netdev(dev); |
| 385 | if (err) { |
| 386 | pr_debug("virtio_net: registering device failed\n"); |
| 387 | goto free_send; |
| 388 | } |
| 389 | pr_debug("virtnet: registered device %s\n", dev->name); |
| 390 | vdev->priv = vi; |
| 391 | return 0; |
| 392 | |
| 393 | free_send: |
| 394 | vdev->config->del_vq(vi->svq); |
| 395 | free_recv: |
| 396 | vdev->config->del_vq(vi->rvq); |
| 397 | free: |
| 398 | free_netdev(dev); |
| 399 | return err; |
| 400 | } |
| 401 | |
| 402 | static void virtnet_remove(struct virtio_device *vdev) |
| 403 | { |
| 404 | unregister_netdev(vdev->priv); |
| 405 | free_netdev(vdev->priv); |
| 406 | } |
| 407 | |
| 408 | static struct virtio_device_id id_table[] = { |
| 409 | { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID }, |
| 410 | { 0 }, |
| 411 | }; |
| 412 | |
| 413 | static struct virtio_driver virtio_net = { |
| 414 | .driver.name = KBUILD_MODNAME, |
| 415 | .driver.owner = THIS_MODULE, |
| 416 | .id_table = id_table, |
| 417 | .probe = virtnet_probe, |
| 418 | .remove = __devexit_p(virtnet_remove), |
| 419 | }; |
| 420 | |
| 421 | static int __init init(void) |
| 422 | { |
| 423 | return register_virtio_driver(&virtio_net); |
| 424 | } |
| 425 | |
| 426 | static void __exit fini(void) |
| 427 | { |
| 428 | unregister_virtio_driver(&virtio_net); |
| 429 | } |
| 430 | module_init(init); |
| 431 | module_exit(fini); |
| 432 | |
| 433 | MODULE_DEVICE_TABLE(virtio, id_table); |
| 434 | MODULE_DESCRIPTION("Virtio network driver"); |
| 435 | MODULE_LICENSE("GPL"); |