/* A simple network driver using virtio. * * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ //#define DEBUG #include <linux/netdevice.h> #include <linux/etherdevice.h> #include <linux/module.h> #include <linux/virtio.h> #include <linux/virtio_net.h> #include <linux/scatterlist.h> /* FIXME: MTU in config. */ #define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN) struct virtnet_info { struct virtio_device *vdev; struct virtqueue *rvq, *svq; struct net_device *dev; struct napi_struct napi; /* Number of input buffers, and max we've ever had. */ unsigned int num, max; /* Receive & send queues. */ struct sk_buff_head recv; struct sk_buff_head send; }; static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb) { return (struct virtio_net_hdr *)skb->cb; } static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb) { sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr)); } static bool skb_xmit_done(struct virtqueue *rvq) { struct virtnet_info *vi = rvq->vdev->priv; /* In case we were waiting for output buffers. */ netif_wake_queue(vi->dev); return true; } static void receive_skb(struct net_device *dev, struct sk_buff *skb, unsigned len) { struct virtio_net_hdr *hdr = skb_vnet_hdr(skb); if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) { pr_debug("%s: short packet %i\n", dev->name, len); dev->stats.rx_length_errors++; goto drop; } len -= sizeof(struct virtio_net_hdr); BUG_ON(len > MAX_PACKET_LEN); skb_trim(skb, len); skb->protocol = eth_type_trans(skb, dev); pr_debug("Receiving skb proto 0x%04x len %i type %i\n", ntohs(skb->protocol), skb->len, skb->pkt_type); dev->stats.rx_bytes += skb->len; dev->stats.rx_packets++; if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { pr_debug("Needs csum!\n"); skb->ip_summed = CHECKSUM_PARTIAL; skb->csum_start = hdr->csum_start; skb->csum_offset = hdr->csum_offset; if (skb->csum_start > skb->len - 2 || skb->csum_offset > skb->len - 2) { if (net_ratelimit()) printk(KERN_WARNING "%s: csum=%u/%u len=%u\n", dev->name, skb->csum_start, skb->csum_offset, skb->len); goto frame_err; } } if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { pr_debug("GSO!\n"); switch (hdr->gso_type) { case VIRTIO_NET_HDR_GSO_TCPV4: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4; break; case VIRTIO_NET_HDR_GSO_TCPV4_ECN: skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN; break; case VIRTIO_NET_HDR_GSO_UDP: skb_shinfo(skb)->gso_type = SKB_GSO_UDP; break; case VIRTIO_NET_HDR_GSO_TCPV6: skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6; break; default: if (net_ratelimit()) printk(KERN_WARNING "%s: bad gso type %u.\n", dev->name, hdr->gso_type); goto frame_err; } skb_shinfo(skb)->gso_size = hdr->gso_size; if (skb_shinfo(skb)->gso_size == 0) { if (net_ratelimit()) printk(KERN_WARNING "%s: zero gso size.\n", dev->name); goto frame_err; } /* Header must be checked, and gso_segs computed. */ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; skb_shinfo(skb)->gso_segs = 0; } netif_receive_skb(skb); return; frame_err: dev->stats.rx_frame_errors++; drop: dev_kfree_skb(skb); } static void try_fill_recv(struct virtnet_info *vi) { struct sk_buff *skb; struct scatterlist sg[1+MAX_SKB_FRAGS]; int num, err; sg_init_table(sg, 1+MAX_SKB_FRAGS); for (;;) { skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN); if (unlikely(!skb)) break; skb_put(skb, MAX_PACKET_LEN); vnet_hdr_to_sg(sg, skb); num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; skb_queue_head(&vi->recv, skb); err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb); if (err) { skb_unlink(skb, &vi->recv); kfree_skb(skb); break; } vi->num++; } if (unlikely(vi->num > vi->max)) vi->max = vi->num; vi->rvq->vq_ops->kick(vi->rvq); } static bool skb_recv_done(struct virtqueue *rvq) { struct virtnet_info *vi = rvq->vdev->priv; netif_rx_schedule(vi->dev, &vi->napi); /* Suppress further interrupts. */ return false; } static int virtnet_poll(struct napi_struct *napi, int budget) { struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi); struct sk_buff *skb = NULL; unsigned int len, received = 0; again: while (received < budget && (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) { __skb_unlink(skb, &vi->recv); receive_skb(vi->dev, skb, len); vi->num--; received++; } /* FIXME: If we oom and completely run out of inbufs, we need * to start a timer trying to fill more. */ if (vi->num < vi->max / 2) try_fill_recv(vi); /* Out of packets? */ if (received < budget) { netif_rx_complete(vi->dev, napi); if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq)) && netif_rx_reschedule(vi->dev, napi)) goto again; } return received; } static void free_old_xmit_skbs(struct virtnet_info *vi) { struct sk_buff *skb; unsigned int len; while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) { pr_debug("Sent skb %p\n", skb); __skb_unlink(skb, &vi->send); vi->dev->stats.tx_bytes += len; vi->dev->stats.tx_packets++; kfree_skb(skb); } } static int start_xmit(struct sk_buff *skb, struct net_device *dev) { struct virtnet_info *vi = netdev_priv(dev); int num, err; struct scatterlist sg[1+MAX_SKB_FRAGS]; struct virtio_net_hdr *hdr; const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; DECLARE_MAC_BUF(mac); sg_init_table(sg, 1+MAX_SKB_FRAGS); pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest)); free_old_xmit_skbs(vi); /* Encode metadata header at front. */ hdr = skb_vnet_hdr(skb); if (skb->ip_summed == CHECKSUM_PARTIAL) { hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; hdr->csum_start = skb->csum_start - skb_headroom(skb); hdr->csum_offset = skb->csum_offset; } else { hdr->flags = 0; hdr->csum_offset = hdr->csum_start = 0; } if (skb_is_gso(skb)) { hdr->gso_size = skb_shinfo(skb)->gso_size; if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN) hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN; else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4) hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP) hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; else BUG(); } else { hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; hdr->gso_size = 0; } vnet_hdr_to_sg(sg, skb); num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; __skb_queue_head(&vi->send, skb); err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb); if (err) { pr_debug("%s: virtio not prepared to send\n", dev->name); skb_unlink(skb, &vi->send); netif_stop_queue(dev); return NETDEV_TX_BUSY; } vi->svq->vq_ops->kick(vi->svq); return 0; } static int virtnet_open(struct net_device *dev) { struct virtnet_info *vi = netdev_priv(dev); try_fill_recv(vi); /* If we didn't even get one input buffer, we're useless. */ if (vi->num == 0) return -ENOMEM; napi_enable(&vi->napi); return 0; } static int virtnet_close(struct net_device *dev) { struct virtnet_info *vi = netdev_priv(dev); struct sk_buff *skb; napi_disable(&vi->napi); /* networking core has neutered skb_xmit_done/skb_recv_done, so don't * worry about races vs. get(). */ vi->rvq->vq_ops->shutdown(vi->rvq); while ((skb = __skb_dequeue(&vi->recv)) != NULL) { kfree_skb(skb); vi->num--; } vi->svq->vq_ops->shutdown(vi->svq); while ((skb = __skb_dequeue(&vi->send)) != NULL) kfree_skb(skb); BUG_ON(vi->num != 0); return 0; } static int virtnet_probe(struct virtio_device *vdev) { int err; unsigned int len; struct net_device *dev; struct virtnet_info *vi; void *token; /* Allocate ourselves a network device with room for our info */ dev = alloc_etherdev(sizeof(struct virtnet_info)); if (!dev) return -ENOMEM; /* Set up network device as normal. */ ether_setup(dev); dev->open = virtnet_open; dev->stop = virtnet_close; dev->hard_start_xmit = start_xmit; dev->features = NETIF_F_HIGHDMA; SET_NETDEV_DEV(dev, &vdev->dev); /* Do we support "hardware" checksums? */ token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len); if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) { /* This opens up the world of extra features. */ dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST; if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4)) dev->features |= NETIF_F_TSO; if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO)) dev->features |= NETIF_F_UFO; if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN)) dev->features |= NETIF_F_TSO_ECN; if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6)) dev->features |= NETIF_F_TSO6; } /* Configuration may specify what MAC to use. Otherwise random. */ token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len); if (token) { dev->addr_len = len; vdev->config->get(vdev, token, dev->dev_addr, len); } else random_ether_addr(dev->dev_addr); /* Set up our device-specific information */ vi = netdev_priv(dev); netif_napi_add(dev, &vi->napi, virtnet_poll, 16); vi->dev = dev; vi->vdev = vdev; /* We expect two virtqueues, receive then send. */ vi->rvq = vdev->config->find_vq(vdev, skb_recv_done); if (IS_ERR(vi->rvq)) { err = PTR_ERR(vi->rvq); goto free; } vi->svq = vdev->config->find_vq(vdev, skb_xmit_done); if (IS_ERR(vi->svq)) { err = PTR_ERR(vi->svq); goto free_recv; } /* Initialize our empty receive and send queues. */ skb_queue_head_init(&vi->recv); skb_queue_head_init(&vi->send); err = register_netdev(dev); if (err) { pr_debug("virtio_net: registering device failed\n"); goto free_send; } pr_debug("virtnet: registered device %s\n", dev->name); vdev->priv = vi; return 0; free_send: vdev->config->del_vq(vi->svq); free_recv: vdev->config->del_vq(vi->rvq); free: free_netdev(dev); return err; } static void virtnet_remove(struct virtio_device *vdev) { struct virtnet_info *vi = vdev->priv; vdev->config->del_vq(vi->svq); vdev->config->del_vq(vi->rvq); unregister_netdev(vi->dev); free_netdev(vi->dev); } static struct virtio_device_id id_table[] = { { VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID }, { 0 }, }; static struct virtio_driver virtio_net = { .driver.name = KBUILD_MODNAME, .driver.owner = THIS_MODULE, .id_table = id_table, .probe = virtnet_probe, .remove = __devexit_p(virtnet_remove), }; static int __init init(void) { return register_virtio_driver(&virtio_net); } static void __exit fini(void) { unregister_virtio_driver(&virtio_net); } module_init(init); module_exit(fini); MODULE_DEVICE_TABLE(virtio, id_table); MODULE_DESCRIPTION("Virtio network driver"); MODULE_LICENSE("GPL");