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 sg_init_table(sg, 1+MAX_SKB_FRAGS); 150 for (;;) { 151 skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN); 152 if (unlikely(!skb)) 153 break; 154 155 skb_put(skb, MAX_PACKET_LEN); 156 vnet_hdr_to_sg(sg, skb); 157 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; 158 skb_queue_head(&vi->recv, skb); 159 160 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb); 161 if (err) { 162 skb_unlink(skb, &vi->recv); 163 kfree_skb(skb); 164 break; 165 } 166 vi->num++; 167 } 168 if (unlikely(vi->num > vi->max)) 169 vi->max = vi->num; 170 vi->rvq->vq_ops->kick(vi->rvq); 171 } 172 173 static bool skb_recv_done(struct virtqueue *rvq) 174 { 175 struct virtnet_info *vi = rvq->vdev->priv; 176 netif_rx_schedule(vi->dev, &vi->napi); 177 /* Suppress further interrupts. */ 178 return false; 179 } 180 181 static int virtnet_poll(struct napi_struct *napi, int budget) 182 { 183 struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi); 184 struct sk_buff *skb = NULL; 185 unsigned int len, received = 0; 186 187 again: 188 while (received < budget && 189 (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) { 190 __skb_unlink(skb, &vi->recv); 191 receive_skb(vi->dev, skb, len); 192 vi->num--; 193 received++; 194 } 195 196 /* FIXME: If we oom and completely run out of inbufs, we need 197 * to start a timer trying to fill more. */ 198 if (vi->num < vi->max / 2) 199 try_fill_recv(vi); 200 201 /* Out of packets? */ 202 if (received < budget) { 203 netif_rx_complete(vi->dev, napi); 204 if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq)) 205 && netif_rx_reschedule(vi->dev, napi)) 206 goto again; 207 } 208 209 return received; 210 } 211 212 static void free_old_xmit_skbs(struct virtnet_info *vi) 213 { 214 struct sk_buff *skb; 215 unsigned int len; 216 217 while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) { 218 pr_debug("Sent skb %p\n", skb); 219 __skb_unlink(skb, &vi->send); 220 vi->dev->stats.tx_bytes += len; 221 vi->dev->stats.tx_packets++; 222 kfree_skb(skb); 223 } 224 } 225 226 static int start_xmit(struct sk_buff *skb, struct net_device *dev) 227 { 228 struct virtnet_info *vi = netdev_priv(dev); 229 int num, err; 230 struct scatterlist sg[1+MAX_SKB_FRAGS]; 231 struct virtio_net_hdr *hdr; 232 const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; 233 DECLARE_MAC_BUF(mac); 234 235 sg_init_table(sg, 1+MAX_SKB_FRAGS); 236 237 pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest)); 238 239 free_old_xmit_skbs(vi); 240 241 /* Encode metadata header at front. */ 242 hdr = skb_vnet_hdr(skb); 243 if (skb->ip_summed == CHECKSUM_PARTIAL) { 244 hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 245 hdr->csum_start = skb->csum_start - skb_headroom(skb); 246 hdr->csum_offset = skb->csum_offset; 247 } else { 248 hdr->flags = 0; 249 hdr->csum_offset = hdr->csum_start = 0; 250 } 251 252 if (skb_is_gso(skb)) { 253 hdr->gso_size = skb_shinfo(skb)->gso_size; 254 if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN) 255 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN; 256 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) 257 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 258 else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) 259 hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 260 else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) 261 hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; 262 else 263 BUG(); 264 } else { 265 hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; 266 hdr->gso_size = 0; 267 } 268 269 vnet_hdr_to_sg(sg, skb); 270 num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; 271 __skb_queue_head(&vi->send, skb); 272 err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb); 273 if (err) { 274 pr_debug("%s: virtio not prepared to send\n", dev->name); 275 skb_unlink(skb, &vi->send); 276 netif_stop_queue(dev); 277 return NETDEV_TX_BUSY; 278 } 279 vi->svq->vq_ops->kick(vi->svq); 280 281 return 0; 282 } 283 284 static int virtnet_open(struct net_device *dev) 285 { 286 struct virtnet_info *vi = netdev_priv(dev); 287 288 try_fill_recv(vi); 289 290 /* If we didn't even get one input buffer, we're useless. */ 291 if (vi->num == 0) 292 return -ENOMEM; 293 294 napi_enable(&vi->napi); 295 return 0; 296 } 297 298 static int virtnet_close(struct net_device *dev) 299 { 300 struct virtnet_info *vi = netdev_priv(dev); 301 struct sk_buff *skb; 302 303 napi_disable(&vi->napi); 304 305 /* networking core has neutered skb_xmit_done/skb_recv_done, so don't 306 * worry about races vs. get(). */ 307 vi->rvq->vq_ops->shutdown(vi->rvq); 308 while ((skb = __skb_dequeue(&vi->recv)) != NULL) { 309 kfree_skb(skb); 310 vi->num--; 311 } 312 vi->svq->vq_ops->shutdown(vi->svq); 313 while ((skb = __skb_dequeue(&vi->send)) != NULL) 314 kfree_skb(skb); 315 316 BUG_ON(vi->num != 0); 317 return 0; 318 } 319 320 static int virtnet_probe(struct virtio_device *vdev) 321 { 322 int err; 323 unsigned int len; 324 struct net_device *dev; 325 struct virtnet_info *vi; 326 void *token; 327 328 /* Allocate ourselves a network device with room for our info */ 329 dev = alloc_etherdev(sizeof(struct virtnet_info)); 330 if (!dev) 331 return -ENOMEM; 332 333 /* Set up network device as normal. */ 334 ether_setup(dev); 335 dev->open = virtnet_open; 336 dev->stop = virtnet_close; 337 dev->hard_start_xmit = start_xmit; 338 dev->features = NETIF_F_HIGHDMA; 339 SET_NETDEV_DEV(dev, &vdev->dev); 340 341 /* Do we support "hardware" checksums? */ 342 token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len); 343 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) { 344 /* This opens up the world of extra features. */ 345 dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST; 346 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4)) 347 dev->features |= NETIF_F_TSO; 348 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO)) 349 dev->features |= NETIF_F_UFO; 350 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN)) 351 dev->features |= NETIF_F_TSO_ECN; 352 if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6)) 353 dev->features |= NETIF_F_TSO6; 354 } 355 356 /* Configuration may specify what MAC to use. Otherwise random. */ 357 token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len); 358 if (token) { 359 dev->addr_len = len; 360 vdev->config->get(vdev, token, dev->dev_addr, len); 361 } else 362 random_ether_addr(dev->dev_addr); 363 364 /* Set up our device-specific information */ 365 vi = netdev_priv(dev); 366 netif_napi_add(dev, &vi->napi, virtnet_poll, 16); 367 vi->dev = dev; 368 vi->vdev = vdev; 369 370 /* We expect two virtqueues, receive then send. */ 371 vi->rvq = vdev->config->find_vq(vdev, skb_recv_done); 372 if (IS_ERR(vi->rvq)) { 373 err = PTR_ERR(vi->rvq); 374 goto free; 375 } 376 377 vi->svq = vdev->config->find_vq(vdev, skb_xmit_done); 378 if (IS_ERR(vi->svq)) { 379 err = PTR_ERR(vi->svq); 380 goto free_recv; 381 } 382 383 /* Initialize our empty receive and send queues. */ 384 skb_queue_head_init(&vi->recv); 385 skb_queue_head_init(&vi->send); 386 387 err = register_netdev(dev); 388 if (err) { 389 pr_debug("virtio_net: registering device failed\n"); 390 goto free_send; 391 } 392 pr_debug("virtnet: registered device %s\n", dev->name); 393 vdev->priv = vi; 394 return 0; 395 396 free_send: 397 vdev->config->del_vq(vi->svq); 398 free_recv: 399 vdev->config->del_vq(vi->rvq); 400 free: 401 free_netdev(dev); 402 return err; 403 } 404 405 static void virtnet_remove(struct virtio_device *vdev) 406 { 407 struct virtnet_info *vi = vdev->priv; 408 409 vdev->config->del_vq(vi->svq); 410 vdev->config->del_vq(vi->rvq); 411 unregister_netdev(vi->dev); 412 free_netdev(vi->dev); 413 } 414 415 static struct virtio_device_id id_table[] = { 416 { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID }, 417 { 0 }, 418 }; 419 420 static struct virtio_driver virtio_net = { 421 .driver.name = KBUILD_MODNAME, 422 .driver.owner = THIS_MODULE, 423 .id_table = id_table, 424 .probe = virtnet_probe, 425 .remove = __devexit_p(virtnet_remove), 426 }; 427 428 static int __init init(void) 429 { 430 return register_virtio_driver(&virtio_net); 431 } 432 433 static void __exit fini(void) 434 { 435 unregister_virtio_driver(&virtio_net); 436 } 437 module_init(init); 438 module_exit(fini); 439 440 MODULE_DEVICE_TABLE(virtio, id_table); 441 MODULE_DESCRIPTION("Virtio network driver"); 442 MODULE_LICENSE("GPL"); 443