[net-next-2.6.git] / drivers / net / virtio_net.c

/* 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>

static int csum = 1, gso = 1;
module_param(csum, bool, 0444);
module_param(gso, bool, 0444);

/* 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 void 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);
}

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");
		if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
			goto frame_err;
	}

	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
		pr_debug("GSO!\n");
		switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
		case VIRTIO_NET_HDR_GSO_TCPV4:
			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
			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;
		}

		if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;

		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 void skb_recv_done(struct virtqueue *rvq)
{
	struct virtnet_info *vi = rvq->vdev->priv;
	/* Schedule NAPI, Suppress further interrupts if successful. */
	if (netif_rx_schedule_prep(vi->dev, &vi->napi)) {
		rvq->vq_ops->disable_cb(rvq);
		__netif_rx_schedule(vi->dev, &vi->napi);
	}
}

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->enable_cb(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->hdr_len = skb_transport_header(skb) - skb->data;
		hdr->gso_size = skb_shinfo(skb)->gso_size;
		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();
		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
			hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
	} else {
		hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
		hdr->gso_size = hdr->hdr_len = 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);

	napi_enable(&vi->napi);
	return 0;
}

static int virtnet_close(struct net_device *dev)
{
	struct virtnet_info *vi = netdev_priv(dev);

	napi_disable(&vi->napi);

	return 0;
}

static int virtnet_probe(struct virtio_device *vdev)
{
	int err;
	struct net_device *dev;
	struct virtnet_info *vi;

	/* 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. */
	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? */
	if (csum && vdev->config->feature(vdev, VIRTIO_NET_F_CSUM)) {
		/* This opens up the world of extra features. */
		dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
		if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_GSO)) {
			dev->features |= NETIF_F_TSO | NETIF_F_UFO
				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
		}
	}

	/* Configuration may specify what MAC to use.  Otherwise random. */
	if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
		vdev->config->get(vdev,
				  offsetof(struct virtio_net_config, mac),
				  dev->dev_addr, 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, 0, skb_recv_done);
	if (IS_ERR(vi->rvq)) {
		err = PTR_ERR(vi->rvq);
		goto free;
	}

	vi->svq = vdev->config->find_vq(vdev, 1, 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;
	}

	/* Last of all, set up some receive buffers. */
	try_fill_recv(vi);

	/* If we didn't even get one input buffer, we're useless. */
	if (vi->num == 0) {
		err = -ENOMEM;
		goto unregister;
	}

	pr_debug("virtnet: registered device %s\n", dev->name);
	vdev->priv = vi;
	return 0;

unregister:
	unregister_netdev(dev);
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;
	struct sk_buff *skb;

	/* Stop all the virtqueues. */
	vdev->config->reset(vdev);

	/* Free our skbs in send and recv queues, if any. */
	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
		kfree_skb(skb);
		vi->num--;
	}
	while ((skb = __skb_dequeue(&vi->send)) != NULL)
		kfree_skb(skb);

	BUG_ON(vi->num != 0);

	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");
Commit	Line	Data
296f96fc RR	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
34a48579 RR	27	static int csum = 1, gso = 1;
	28	module_param(csum, bool, 0444);
	29	module_param(gso, bool, 0444);
	30
296f96fc RR	31	/* FIXME: MTU in config. */
	32	#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
	33
	34	struct virtnet_info
	35	{
	36	struct virtio_device *vdev;
	37	struct virtqueue rvq, svq;
	38	struct net_device *dev;
	39	struct napi_struct napi;
	40
	41	/* Number of input buffers, and max we've ever had. */
	42	unsigned int num, max;
	43
	44	/* Receive & send queues. */
	45	struct sk_buff_head recv;
	46	struct sk_buff_head send;
	47	};
	48
	49	static inline struct virtio_net_hdr skb_vnet_hdr(struct sk_buff skb)
	50	{
	51	return (struct virtio_net_hdr *)skb->cb;
	52	}
	53
	54	static inline void vnet_hdr_to_sg(struct scatterlist sg, struct sk_buff skb)
	55	{
	56	sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
	57	}
	58
18445c4d	59	static void skb_xmit_done(struct virtqueue *rvq)
296f96fc RR	60	{
	61	struct virtnet_info *vi = rvq->vdev->priv;
	62
	63	/* In case we were waiting for output buffers. */
	64	netif_wake_queue(vi->dev);
296f96fc RR	65	}
	66
	67	static void receive_skb(struct net_device dev, struct sk_buff skb,
	68	unsigned len)
	69	{
	70	struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
	71
	72	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
	73	pr_debug("%s: short packet %i\n", dev->name, len);
	74	dev->stats.rx_length_errors++;
	75	goto drop;
	76	}
	77	len -= sizeof(struct virtio_net_hdr);
	78	BUG_ON(len > MAX_PACKET_LEN);
	79
	80	skb_trim(skb, len);
	81	skb->protocol = eth_type_trans(skb, dev);
	82	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
	83	ntohs(skb->protocol), skb->len, skb->pkt_type);
	84	dev->stats.rx_bytes += skb->len;
	85	dev->stats.rx_packets++;
	86
	87	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
	88	pr_debug("Needs csum!\n");
f35d9d8a	89	if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
296f96fc	90	goto frame_err;
296f96fc RR	91	}
	92
	93	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
	94	pr_debug("GSO!\n");
34a48579	95	switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
296f96fc RR	96	case VIRTIO_NET_HDR_GSO_TCPV4:
	97	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
	98	break;
296f96fc RR	99	case VIRTIO_NET_HDR_GSO_UDP:
	100	skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
	101	break;
	102	case VIRTIO_NET_HDR_GSO_TCPV6:
	103	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
	104	break;
	105	default:
	106	if (net_ratelimit())
	107	printk(KERN_WARNING "%s: bad gso type %u.\n",
	108	dev->name, hdr->gso_type);
	109	goto frame_err;
	110	}
	111
34a48579 RR	112	if (hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
	113	skb_shinfo(skb)->gso_type \|= SKB_GSO_TCP_ECN;
	114
296f96fc RR	115	skb_shinfo(skb)->gso_size = hdr->gso_size;
	116	if (skb_shinfo(skb)->gso_size == 0) {
	117	if (net_ratelimit())
	118	printk(KERN_WARNING "%s: zero gso size.\n",
	119	dev->name);
	120	goto frame_err;
	121	}
	122
	123	/* Header must be checked, and gso_segs computed. */
	124	skb_shinfo(skb)->gso_type \|= SKB_GSO_DODGY;
	125	skb_shinfo(skb)->gso_segs = 0;
	126	}
	127
	128	netif_receive_skb(skb);
	129	return;
	130
	131	frame_err:
	132	dev->stats.rx_frame_errors++;
	133	drop:
	134	dev_kfree_skb(skb);
	135	}
	136
	137	static void try_fill_recv(struct virtnet_info *vi)
	138	{
	139	struct sk_buff *skb;
	140	struct scatterlist sg[1+MAX_SKB_FRAGS];
	141	int num, err;
	142
4d125de3	143	sg_init_table(sg, 1+MAX_SKB_FRAGS);
296f96fc RR	144	for (;;) {
	145	skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
	146	if (unlikely(!skb))
	147	break;
	148
	149	skb_put(skb, MAX_PACKET_LEN);
	150	vnet_hdr_to_sg(sg, skb);
	151	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
	152	skb_queue_head(&vi->recv, skb);
	153
	154	err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
	155	if (err) {
	156	skb_unlink(skb, &vi->recv);
	157	kfree_skb(skb);
	158	break;
	159	}
	160	vi->num++;
	161	}
	162	if (unlikely(vi->num > vi->max))
	163	vi->max = vi->num;
	164	vi->rvq->vq_ops->kick(vi->rvq);
	165	}
	166
18445c4d	167	static void skb_recv_done(struct virtqueue *rvq)
296f96fc RR	168	{
296f96fc RR	169	struct virtnet_info *vi = rvq->vdev->priv;
18445c4d RR	170	/* Schedule NAPI, Suppress further interrupts if successful. */
	171	if (netif_rx_schedule_prep(vi->dev, &vi->napi)) {
	172	rvq->vq_ops->disable_cb(rvq);
	173	__netif_rx_schedule(vi->dev, &vi->napi);
	174	}
296f96fc RR	175	}
	176
	177	static int virtnet_poll(struct napi_struct *napi, int budget)
	178	{
	179	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
	180	struct sk_buff *skb = NULL;
	181	unsigned int len, received = 0;
	182
	183	again:
	184	while (received < budget &&
	185	(skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
	186	__skb_unlink(skb, &vi->recv);
	187	receive_skb(vi->dev, skb, len);
	188	vi->num--;
	189	received++;
	190	}
	191
	192	/* FIXME: If we oom and completely run out of inbufs, we need
	193	* to start a timer trying to fill more. */
	194	if (vi->num < vi->max / 2)
	195	try_fill_recv(vi);
	196
8329d98e RR	197	/* Out of packets? */
8329d98e RR	198	if (received < budget) {
296f96fc	199	netif_rx_complete(vi->dev, napi);
18445c4d	200	if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
296f96fc RR	201	&& netif_rx_reschedule(vi->dev, napi))
	202	goto again;
	203	}
	204
	205	return received;
	206	}
	207
	208	static void free_old_xmit_skbs(struct virtnet_info *vi)
	209	{
	210	struct sk_buff *skb;
	211	unsigned int len;
	212
	213	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
	214	pr_debug("Sent skb %p\n", skb);
	215	__skb_unlink(skb, &vi->send);
	216	vi->dev->stats.tx_bytes += len;
	217	vi->dev->stats.tx_packets++;
	218	kfree_skb(skb);
	219	}
	220	}
	221
	222	static int start_xmit(struct sk_buff skb, struct net_device dev)
	223	{
	224	struct virtnet_info *vi = netdev_priv(dev);
	225	int num, err;
	226	struct scatterlist sg[1+MAX_SKB_FRAGS];
	227	struct virtio_net_hdr *hdr;
	228	const unsigned char dest = ((struct ethhdr )skb->data)->h_dest;
	229	DECLARE_MAC_BUF(mac);
	230
4d125de3 RR	231	sg_init_table(sg, 1+MAX_SKB_FRAGS);
4d125de3 RR	232
296f96fc RR	233	pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
	234
	235	free_old_xmit_skbs(vi);
	236
	237	/* Encode metadata header at front. */
	238	hdr = skb_vnet_hdr(skb);
	239	if (skb->ip_summed == CHECKSUM_PARTIAL) {
	240	hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
	241	hdr->csum_start = skb->csum_start - skb_headroom(skb);
	242	hdr->csum_offset = skb->csum_offset;
	243	} else {
	244	hdr->flags = 0;
	245	hdr->csum_offset = hdr->csum_start = 0;
	246	}
	247
	248	if (skb_is_gso(skb)) {
50c8ea80	249	hdr->hdr_len = skb_transport_header(skb) - skb->data;
296f96fc	250	hdr->gso_size = skb_shinfo(skb)->gso_size;
34a48579	251	if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
296f96fc RR	252	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
	253	else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
	254	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
	255	else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
	256	hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
	257	else
	258	BUG();
34a48579 RR	259	if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
34a48579 RR	260	hdr->gso_type \|= VIRTIO_NET_HDR_GSO_ECN;
296f96fc RR	261	} else {
296f96fc RR	262	hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
50c8ea80	263	hdr->gso_size = hdr->hdr_len = 0;
296f96fc RR	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
296f96fc RR	285	napi_enable(&vi->napi);
	286	return 0;
	287	}
	288
	289	static int virtnet_close(struct net_device *dev)
	290	{
	291	struct virtnet_info *vi = netdev_priv(dev);
296f96fc RR	292
	293	napi_disable(&vi->napi);
	294
296f96fc RR	295	return 0;
	296	}
	297
	298	static int virtnet_probe(struct virtio_device *vdev)
	299	{
	300	int err;
296f96fc RR	301	struct net_device *dev;
296f96fc RR	302	struct virtnet_info *vi;
296f96fc RR	303
	304	/* Allocate ourselves a network device with room for our info */
	305	dev = alloc_etherdev(sizeof(struct virtnet_info));
	306	if (!dev)
	307	return -ENOMEM;
	308
	309	/* Set up network device as normal. */
296f96fc RR	310	dev->open = virtnet_open;
	311	dev->stop = virtnet_close;
	312	dev->hard_start_xmit = start_xmit;
	313	dev->features = NETIF_F_HIGHDMA;
	314	SET_NETDEV_DEV(dev, &vdev->dev);
	315
	316	/* Do we support "hardware" checksums? */
34a48579	317	if (csum && vdev->config->feature(vdev, VIRTIO_NET_F_CSUM)) {
296f96fc RR	318	/* This opens up the world of extra features. */
296f96fc RR	319	dev->features \|= NETIF_F_HW_CSUM\|NETIF_F_SG\|NETIF_F_FRAGLIST;
34a48579 RR	320	if (gso && vdev->config->feature(vdev, VIRTIO_NET_F_GSO)) {
	321	dev->features \|= NETIF_F_TSO \| NETIF_F_UFO
	322	\| NETIF_F_TSO_ECN \| NETIF_F_TSO6;
	323	}
296f96fc RR	324	}
	325
	326	/* Configuration may specify what MAC to use. Otherwise random. */
a586d4f6 RR	327	if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
	328	vdev->config->get(vdev,
	329	offsetof(struct virtio_net_config, mac),
	330	dev->dev_addr, dev->addr_len);
296f96fc RR	331	} else
	332	random_ether_addr(dev->dev_addr);
	333
	334	/* Set up our device-specific information */
	335	vi = netdev_priv(dev);
	336	netif_napi_add(dev, &vi->napi, virtnet_poll, 16);
	337	vi->dev = dev;
	338	vi->vdev = vdev;
	339
	340	/* We expect two virtqueues, receive then send. */
a586d4f6	341	vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
296f96fc RR	342	if (IS_ERR(vi->rvq)) {
	343	err = PTR_ERR(vi->rvq);
	344	goto free;
	345	}
	346
a586d4f6	347	vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
296f96fc RR	348	if (IS_ERR(vi->svq)) {
	349	err = PTR_ERR(vi->svq);
	350	goto free_recv;
	351	}
	352
	353	/* Initialize our empty receive and send queues. */
	354	skb_queue_head_init(&vi->recv);
	355	skb_queue_head_init(&vi->send);
	356
	357	err = register_netdev(dev);
	358	if (err) {
	359	pr_debug("virtio_net: registering device failed\n");
	360	goto free_send;
	361	}
b3369c1f RR	362
	363	/* Last of all, set up some receive buffers. */
	364	try_fill_recv(vi);
	365
	366	/* If we didn't even get one input buffer, we're useless. */
	367	if (vi->num == 0) {
	368	err = -ENOMEM;
	369	goto unregister;
	370	}
	371
296f96fc RR	372	pr_debug("virtnet: registered device %s\n", dev->name);
	373	vdev->priv = vi;
	374	return 0;
	375
b3369c1f RR	376	unregister:
b3369c1f RR	377	unregister_netdev(dev);
296f96fc RR	378	free_send:
	379	vdev->config->del_vq(vi->svq);
	380	free_recv:
	381	vdev->config->del_vq(vi->rvq);
	382	free:
	383	free_netdev(dev);
	384	return err;
	385	}
	386
	387	static void virtnet_remove(struct virtio_device *vdev)
	388	{
74b2553f	389	struct virtnet_info *vi = vdev->priv;
b3369c1f RR	390	struct sk_buff *skb;
b3369c1f RR	391
6e5aa7ef RR	392	/* Stop all the virtqueues. */
	393	vdev->config->reset(vdev);
	394
b3369c1f	395	/* Free our skbs in send and recv queues, if any. */
b3369c1f RR	396	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
	397	kfree_skb(skb);
	398	vi->num--;
	399	}
b3369c1f RR	400	while ((skb = __skb_dequeue(&vi->send)) != NULL)
	401	kfree_skb(skb);
	402
	403	BUG_ON(vi->num != 0);
74b2553f RR	404
	405	vdev->config->del_vq(vi->svq);
	406	vdev->config->del_vq(vi->rvq);
	407	unregister_netdev(vi->dev);
	408	free_netdev(vi->dev);
296f96fc RR	409	}
	410
	411	static struct virtio_device_id id_table[] = {
	412	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
	413	{ 0 },
	414	};
	415
	416	static struct virtio_driver virtio_net = {
	417	.driver.name = KBUILD_MODNAME,
	418	.driver.owner = THIS_MODULE,
	419	.id_table = id_table,
	420	.probe = virtnet_probe,
	421	.remove = __devexit_p(virtnet_remove),
	422	};
	423
	424	static int __init init(void)
	425	{
	426	return register_virtio_driver(&virtio_net);
	427	}
	428
	429	static void __exit fini(void)
	430	{
	431	unregister_virtio_driver(&virtio_net);
	432	}
	433	module_init(init);
	434	module_exit(fini);
	435
	436	MODULE_DEVICE_TABLE(virtio, id_table);
	437	MODULE_DESCRIPTION("Virtio network driver");
	438	MODULE_LICENSE("GPL");