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"); 436