Net driver using virtio
The network driver uses two virtqueues: one for input packets and one for output packets. This has nice locking properties (ie. we don't do any for recv vs send). TODO: 1) Big packets. 2) Multi-client devices (maybe separate driver?). 3) Resolve freeing of old xmit skbs (Christian Borntraeger) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: netdev@vger.kernel.org
This commit is contained in:
Rusty Russell
parent
ec3d41c4db
commit
296f96fcfc
@ -3100,4 +3100,10 @@ config NETPOLL_TRAP
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config NET_POLL_CONTROLLER
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def_bool NETPOLL
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config VIRTIO_NET
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tristate "Virtio network driver (EXPERIMENTAL)"
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depends on EXPERIMENTAL && VIRTIO
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---help---
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This is the virtual network driver for lguest. Say Y or M.
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endif # NETDEVICES
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@ -243,3 +243,4 @@ obj-$(CONFIG_FS_ENET) += fs_enet/
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obj-$(CONFIG_NETXEN_NIC) += netxen/
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obj-$(CONFIG_NIU) += niu.o
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obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
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435
drivers/net/virtio_net.c
Normal file
435
drivers/net/virtio_net.c
Normal file
@ -0,0 +1,435 @@
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/* A simple network driver using virtio.
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*
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* Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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//#define DEBUG
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/module.h>
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#include <linux/virtio.h>
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#include <linux/virtio_net.h>
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#include <linux/scatterlist.h>
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/* FIXME: MTU in config. */
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#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
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struct virtnet_info
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{
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struct virtio_device *vdev;
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struct virtqueue *rvq, *svq;
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struct net_device *dev;
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struct napi_struct napi;
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/* Number of input buffers, and max we've ever had. */
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unsigned int num, max;
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/* Receive & send queues. */
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struct sk_buff_head recv;
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struct sk_buff_head send;
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};
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static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
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{
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return (struct virtio_net_hdr *)skb->cb;
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}
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static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
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{
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sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
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}
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static bool skb_xmit_done(struct virtqueue *rvq)
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{
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struct virtnet_info *vi = rvq->vdev->priv;
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/* In case we were waiting for output buffers. */
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netif_wake_queue(vi->dev);
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return true;
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}
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static void receive_skb(struct net_device *dev, struct sk_buff *skb,
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unsigned len)
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{
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struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
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if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
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pr_debug("%s: short packet %i\n", dev->name, len);
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dev->stats.rx_length_errors++;
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goto drop;
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}
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len -= sizeof(struct virtio_net_hdr);
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BUG_ON(len > MAX_PACKET_LEN);
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skb_trim(skb, len);
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skb->protocol = eth_type_trans(skb, dev);
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pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
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ntohs(skb->protocol), skb->len, skb->pkt_type);
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dev->stats.rx_bytes += skb->len;
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dev->stats.rx_packets++;
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if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
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pr_debug("Needs csum!\n");
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skb->ip_summed = CHECKSUM_PARTIAL;
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skb->csum_start = hdr->csum_start;
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skb->csum_offset = hdr->csum_offset;
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if (skb->csum_start > skb->len - 2
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|| skb->csum_offset > skb->len - 2) {
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if (net_ratelimit())
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printk(KERN_WARNING "%s: csum=%u/%u len=%u\n",
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dev->name, skb->csum_start,
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skb->csum_offset, skb->len);
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goto frame_err;
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}
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}
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if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
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pr_debug("GSO!\n");
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switch (hdr->gso_type) {
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case VIRTIO_NET_HDR_GSO_TCPV4:
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skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
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break;
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case VIRTIO_NET_HDR_GSO_TCPV4_ECN:
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skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN;
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break;
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case VIRTIO_NET_HDR_GSO_UDP:
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skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
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break;
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case VIRTIO_NET_HDR_GSO_TCPV6:
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skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
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break;
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default:
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if (net_ratelimit())
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printk(KERN_WARNING "%s: bad gso type %u.\n",
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dev->name, hdr->gso_type);
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goto frame_err;
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}
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skb_shinfo(skb)->gso_size = hdr->gso_size;
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if (skb_shinfo(skb)->gso_size == 0) {
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if (net_ratelimit())
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printk(KERN_WARNING "%s: zero gso size.\n",
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dev->name);
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goto frame_err;
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}
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/* Header must be checked, and gso_segs computed. */
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skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
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skb_shinfo(skb)->gso_segs = 0;
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}
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netif_receive_skb(skb);
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return;
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frame_err:
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dev->stats.rx_frame_errors++;
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drop:
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dev_kfree_skb(skb);
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}
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static void try_fill_recv(struct virtnet_info *vi)
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{
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struct sk_buff *skb;
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struct scatterlist sg[1+MAX_SKB_FRAGS];
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int num, err;
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for (;;) {
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skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
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if (unlikely(!skb))
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break;
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skb_put(skb, MAX_PACKET_LEN);
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vnet_hdr_to_sg(sg, skb);
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num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
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skb_queue_head(&vi->recv, skb);
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err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
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if (err) {
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skb_unlink(skb, &vi->recv);
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kfree_skb(skb);
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break;
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}
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vi->num++;
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}
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if (unlikely(vi->num > vi->max))
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vi->max = vi->num;
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vi->rvq->vq_ops->kick(vi->rvq);
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}
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static bool skb_recv_done(struct virtqueue *rvq)
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{
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struct virtnet_info *vi = rvq->vdev->priv;
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netif_rx_schedule(vi->dev, &vi->napi);
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/* Suppress further interrupts. */
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return false;
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}
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static int virtnet_poll(struct napi_struct *napi, int budget)
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{
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struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
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struct sk_buff *skb = NULL;
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unsigned int len, received = 0;
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again:
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while (received < budget &&
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(skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
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__skb_unlink(skb, &vi->recv);
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receive_skb(vi->dev, skb, len);
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vi->num--;
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received++;
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}
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/* FIXME: If we oom and completely run out of inbufs, we need
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* to start a timer trying to fill more. */
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if (vi->num < vi->max / 2)
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try_fill_recv(vi);
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/* All done? */
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if (!skb) {
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netif_rx_complete(vi->dev, napi);
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if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq))
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&& netif_rx_reschedule(vi->dev, napi))
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goto again;
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}
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return received;
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}
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static void free_old_xmit_skbs(struct virtnet_info *vi)
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{
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struct sk_buff *skb;
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unsigned int len;
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while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
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pr_debug("Sent skb %p\n", skb);
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__skb_unlink(skb, &vi->send);
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vi->dev->stats.tx_bytes += len;
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vi->dev->stats.tx_packets++;
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kfree_skb(skb);
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}
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}
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static int start_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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struct virtnet_info *vi = netdev_priv(dev);
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int num, err;
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struct scatterlist sg[1+MAX_SKB_FRAGS];
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struct virtio_net_hdr *hdr;
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const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
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DECLARE_MAC_BUF(mac);
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pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
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free_old_xmit_skbs(vi);
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/* Encode metadata header at front. */
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hdr = skb_vnet_hdr(skb);
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if (skb->ip_summed == CHECKSUM_PARTIAL) {
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hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
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hdr->csum_start = skb->csum_start - skb_headroom(skb);
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hdr->csum_offset = skb->csum_offset;
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} else {
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hdr->flags = 0;
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hdr->csum_offset = hdr->csum_start = 0;
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}
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if (skb_is_gso(skb)) {
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hdr->gso_size = skb_shinfo(skb)->gso_size;
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if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
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hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN;
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else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
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hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
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else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
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hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
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else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
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hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
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else
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BUG();
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} else {
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hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
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hdr->gso_size = 0;
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}
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vnet_hdr_to_sg(sg, skb);
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num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
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__skb_queue_head(&vi->send, skb);
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err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
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if (err) {
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pr_debug("%s: virtio not prepared to send\n", dev->name);
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skb_unlink(skb, &vi->send);
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netif_stop_queue(dev);
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return NETDEV_TX_BUSY;
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}
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vi->svq->vq_ops->kick(vi->svq);
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return 0;
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}
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static int virtnet_open(struct net_device *dev)
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{
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struct virtnet_info *vi = netdev_priv(dev);
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try_fill_recv(vi);
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/* If we didn't even get one input buffer, we're useless. */
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if (vi->num == 0)
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return -ENOMEM;
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napi_enable(&vi->napi);
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return 0;
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}
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static int virtnet_close(struct net_device *dev)
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{
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struct virtnet_info *vi = netdev_priv(dev);
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struct sk_buff *skb;
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napi_disable(&vi->napi);
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/* networking core has neutered skb_xmit_done/skb_recv_done, so don't
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* worry about races vs. get(). */
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vi->rvq->vq_ops->shutdown(vi->rvq);
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while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
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kfree_skb(skb);
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vi->num--;
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}
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vi->svq->vq_ops->shutdown(vi->svq);
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while ((skb = __skb_dequeue(&vi->send)) != NULL)
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kfree_skb(skb);
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BUG_ON(vi->num != 0);
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return 0;
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}
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static int virtnet_probe(struct virtio_device *vdev)
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{
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int err;
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unsigned int len;
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struct net_device *dev;
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struct virtnet_info *vi;
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void *token;
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/* Allocate ourselves a network device with room for our info */
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dev = alloc_etherdev(sizeof(struct virtnet_info));
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if (!dev)
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return -ENOMEM;
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/* Set up network device as normal. */
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ether_setup(dev);
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dev->open = virtnet_open;
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dev->stop = virtnet_close;
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dev->hard_start_xmit = start_xmit;
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dev->features = NETIF_F_HIGHDMA;
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SET_NETDEV_DEV(dev, &vdev->dev);
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/* Do we support "hardware" checksums? */
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token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len);
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if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) {
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/* This opens up the world of extra features. */
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dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
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if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4))
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dev->features |= NETIF_F_TSO;
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if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO))
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dev->features |= NETIF_F_UFO;
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if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN))
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dev->features |= NETIF_F_TSO_ECN;
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if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6))
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dev->features |= NETIF_F_TSO6;
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}
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/* Configuration may specify what MAC to use. Otherwise random. */
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token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len);
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if (token) {
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dev->addr_len = len;
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vdev->config->get(vdev, token, dev->dev_addr, len);
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} else
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random_ether_addr(dev->dev_addr);
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/* Set up our device-specific information */
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vi = netdev_priv(dev);
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netif_napi_add(dev, &vi->napi, virtnet_poll, 16);
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vi->dev = dev;
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vi->vdev = vdev;
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/* We expect two virtqueues, receive then send. */
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vi->rvq = vdev->config->find_vq(vdev, skb_recv_done);
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if (IS_ERR(vi->rvq)) {
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err = PTR_ERR(vi->rvq);
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goto free;
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}
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vi->svq = vdev->config->find_vq(vdev, skb_xmit_done);
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if (IS_ERR(vi->svq)) {
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err = PTR_ERR(vi->svq);
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goto free_recv;
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}
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/* Initialize our empty receive and send queues. */
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skb_queue_head_init(&vi->recv);
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skb_queue_head_init(&vi->send);
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err = register_netdev(dev);
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if (err) {
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pr_debug("virtio_net: registering device failed\n");
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goto free_send;
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}
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pr_debug("virtnet: registered device %s\n", dev->name);
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vdev->priv = vi;
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return 0;
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free_send:
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vdev->config->del_vq(vi->svq);
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free_recv:
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vdev->config->del_vq(vi->rvq);
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free:
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free_netdev(dev);
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return err;
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}
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static void virtnet_remove(struct virtio_device *vdev)
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{
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unregister_netdev(vdev->priv);
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free_netdev(vdev->priv);
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}
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static struct virtio_device_id id_table[] = {
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{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
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{ 0 },
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};
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static struct virtio_driver virtio_net = {
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.driver.name = KBUILD_MODNAME,
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.driver.owner = THIS_MODULE,
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.id_table = id_table,
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.probe = virtnet_probe,
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.remove = __devexit_p(virtnet_remove),
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};
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static int __init init(void)
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{
|
||||
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");
|
||||
@ -344,6 +344,7 @@ unifdef-y += utsname.h
|
||||
unifdef-y += videodev2.h
|
||||
unifdef-y += videodev.h
|
||||
unifdef-y += virtio_config.h
|
||||
unifdef-y += virtio_net.h
|
||||
unifdef-y += wait.h
|
||||
unifdef-y += wanrouter.h
|
||||
unifdef-y += watchdog.h
|
||||
|
||||
36
include/linux/virtio_net.h
Normal file
36
include/linux/virtio_net.h
Normal file
@ -0,0 +1,36 @@
|
||||
#ifndef _LINUX_VIRTIO_NET_H
|
||||
#define _LINUX_VIRTIO_NET_H
|
||||
#include <linux/virtio_config.h>
|
||||
|
||||
/* The ID for virtio_net */
|
||||
#define VIRTIO_ID_NET 1
|
||||
|
||||
/* The bitmap of config for virtio net */
|
||||
#define VIRTIO_CONFIG_NET_F 0x40
|
||||
#define VIRTIO_NET_F_NO_CSUM 0
|
||||
#define VIRTIO_NET_F_TSO4 1
|
||||
#define VIRTIO_NET_F_UFO 2
|
||||
#define VIRTIO_NET_F_TSO4_ECN 3
|
||||
#define VIRTIO_NET_F_TSO6 4
|
||||
|
||||
/* The config defining mac address. */
|
||||
#define VIRTIO_CONFIG_NET_MAC_F 0x41
|
||||
|
||||
/* This is the first element of the scatter-gather list. If you don't
|
||||
* specify GSO or CSUM features, you can simply ignore the header. */
|
||||
struct virtio_net_hdr
|
||||
{
|
||||
#define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 // Use csum_start, csum_offset
|
||||
__u8 flags;
|
||||
#define VIRTIO_NET_HDR_GSO_NONE 0 // Not a GSO frame
|
||||
#define VIRTIO_NET_HDR_GSO_TCPV4 1 // GSO frame, IPv4 TCP (TSO)
|
||||
/* FIXME: Do we need this? If they said they can handle ECN, do they care? */
|
||||
#define VIRTIO_NET_HDR_GSO_TCPV4_ECN 2 // GSO frame, IPv4 TCP w/ ECN
|
||||
#define VIRTIO_NET_HDR_GSO_UDP 3 // GSO frame, IPv4 UDP (UFO)
|
||||
#define VIRTIO_NET_HDR_GSO_TCPV6 4 // GSO frame, IPv6 TCP
|
||||
__u8 gso_type;
|
||||
__u16 gso_size;
|
||||
__u16 csum_start;
|
||||
__u16 csum_offset;
|
||||
};
|
||||
#endif /* _LINUX_VIRTIO_NET_H */
|
||||
Loading…
Reference in New Issue
Block a user