[mirror_ubuntu-bionic-kernel.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>

/* 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");
		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) {
		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;
	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. */
	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? */
	if (vdev->config->feature(vdev, 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 (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4))
			dev->features |= NETIF_F_TSO;
		if (vdev->config->feature(vdev, VIRTIO_NET_F_UFO))
			dev->features |= NETIF_F_UFO;
		if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4_ECN))
			dev->features |= NETIF_F_TSO_ECN;
		if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO6))
			dev->features |= 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;
	}
	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");
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
	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");
f35d9d8a	86	if (!skb_partial_csum_set(skb,hdr->csum_start,hdr->csum_offset))
296f96fc	87	goto frame_err;
296f96fc RR	88	}
	89
	90	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
	91	pr_debug("GSO!\n");
	92	switch (hdr->gso_type) {
	93	case VIRTIO_NET_HDR_GSO_TCPV4:
	94	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
	95	break;
	96	case VIRTIO_NET_HDR_GSO_TCPV4_ECN:
	97	skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN;
	98	break;
	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
	112	skb_shinfo(skb)->gso_size = hdr->gso_size;
	113	if (skb_shinfo(skb)->gso_size == 0) {
	114	if (net_ratelimit())
	115	printk(KERN_WARNING "%s: zero gso size.\n",
	116	dev->name);
	117	goto frame_err;
	118	}
	119
	120	/* Header must be checked, and gso_segs computed. */
	121	skb_shinfo(skb)->gso_type \|= SKB_GSO_DODGY;
	122	skb_shinfo(skb)->gso_segs = 0;
	123	}
	124
	125	netif_receive_skb(skb);
	126	return;
	127
	128	frame_err:
	129	dev->stats.rx_frame_errors++;
	130	drop:
	131	dev_kfree_skb(skb);
	132	}
	133
	134	static void try_fill_recv(struct virtnet_info *vi)
	135	{
	136	struct sk_buff *skb;
	137	struct scatterlist sg[1+MAX_SKB_FRAGS];
	138	int num, err;
	139
4d125de3	140	sg_init_table(sg, 1+MAX_SKB_FRAGS);
296f96fc RR	141	for (;;) {
	142	skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
	143	if (unlikely(!skb))
	144	break;
	145
	146	skb_put(skb, MAX_PACKET_LEN);
	147	vnet_hdr_to_sg(sg, skb);
	148	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
	149	skb_queue_head(&vi->recv, skb);
	150
	151	err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
	152	if (err) {
	153	skb_unlink(skb, &vi->recv);
	154	kfree_skb(skb);
	155	break;
	156	}
	157	vi->num++;
	158	}
	159	if (unlikely(vi->num > vi->max))
	160	vi->max = vi->num;
	161	vi->rvq->vq_ops->kick(vi->rvq);
	162	}
	163
	164	static bool skb_recv_done(struct virtqueue *rvq)
	165	{
	166	struct virtnet_info *vi = rvq->vdev->priv;
	167	netif_rx_schedule(vi->dev, &vi->napi);
	168	/* Suppress further interrupts. */
	169	return false;
	170	}
	171
	172	static int virtnet_poll(struct napi_struct *napi, int budget)
	173	{
	174	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
	175	struct sk_buff *skb = NULL;
	176	unsigned int len, received = 0;
	177
	178	again:
	179	while (received < budget &&
	180	(skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
	181	__skb_unlink(skb, &vi->recv);
	182	receive_skb(vi->dev, skb, len);
	183	vi->num--;
	184	received++;
	185	}
	186
	187	/* FIXME: If we oom and completely run out of inbufs, we need
	188	* to start a timer trying to fill more. */
	189	if (vi->num < vi->max / 2)
	190	try_fill_recv(vi);
	191
8329d98e RR	192	/* Out of packets? */
8329d98e RR	193	if (received < budget) {
296f96fc RR	194	netif_rx_complete(vi->dev, napi);
	195	if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq))
	196	&& netif_rx_reschedule(vi->dev, napi))
	197	goto again;
	198	}
	199
	200	return received;
	201	}
	202
	203	static void free_old_xmit_skbs(struct virtnet_info *vi)
	204	{
	205	struct sk_buff *skb;
	206	unsigned int len;
	207
	208	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
	209	pr_debug("Sent skb %p\n", skb);
	210	__skb_unlink(skb, &vi->send);
	211	vi->dev->stats.tx_bytes += len;
	212	vi->dev->stats.tx_packets++;
	213	kfree_skb(skb);
	214	}
	215	}
	216
	217	static int start_xmit(struct sk_buff skb, struct net_device dev)
	218	{
	219	struct virtnet_info *vi = netdev_priv(dev);
	220	int num, err;
	221	struct scatterlist sg[1+MAX_SKB_FRAGS];
	222	struct virtio_net_hdr *hdr;
	223	const unsigned char dest = ((struct ethhdr )skb->data)->h_dest;
	224	DECLARE_MAC_BUF(mac);
	225
4d125de3 RR	226	sg_init_table(sg, 1+MAX_SKB_FRAGS);
4d125de3 RR	227
296f96fc RR	228	pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
	229
	230	free_old_xmit_skbs(vi);
	231
	232	/* Encode metadata header at front. */
	233	hdr = skb_vnet_hdr(skb);
	234	if (skb->ip_summed == CHECKSUM_PARTIAL) {
	235	hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
	236	hdr->csum_start = skb->csum_start - skb_headroom(skb);
	237	hdr->csum_offset = skb->csum_offset;
	238	} else {
	239	hdr->flags = 0;
	240	hdr->csum_offset = hdr->csum_start = 0;
	241	}
	242
	243	if (skb_is_gso(skb)) {
	244	hdr->gso_size = skb_shinfo(skb)->gso_size;
	245	if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
	246	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN;
	247	else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
	248	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
	249	else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
	250	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
	251	else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
	252	hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
	253	else
	254	BUG();
	255	} else {
	256	hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
	257	hdr->gso_size = 0;
	258	}
	259
	260	vnet_hdr_to_sg(sg, skb);
	261	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
	262	__skb_queue_head(&vi->send, skb);
	263	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
	264	if (err) {
	265	pr_debug("%s: virtio not prepared to send\n", dev->name);
	266	skb_unlink(skb, &vi->send);
	267	netif_stop_queue(dev);
	268	return NETDEV_TX_BUSY;
	269	}
	270	vi->svq->vq_ops->kick(vi->svq);
	271
	272	return 0;
	273	}
	274
	275	static int virtnet_open(struct net_device *dev)
	276	{
	277	struct virtnet_info *vi = netdev_priv(dev);
	278
	279	try_fill_recv(vi);
	280
	281	/* If we didn't even get one input buffer, we're useless. */
	282	if (vi->num == 0)
	283	return -ENOMEM;
	284
	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);
292	struct sk_buff *skb;
293
294	napi_disable(&vi->napi);
295
296	/* networking core has neutered skb_xmit_done/skb_recv_done, so don't
297	* worry about races vs. get(). */
298	vi->rvq->vq_ops->shutdown(vi->rvq);
299	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
300	kfree_skb(skb);
301	vi->num--;
302	}
303	vi->svq->vq_ops->shutdown(vi->svq);
304	while ((skb = __skb_dequeue(&vi->send)) != NULL)
305	kfree_skb(skb);
306
307	BUG_ON(vi->num != 0);
308	return 0;
309	}
310
311	static int virtnet_probe(struct virtio_device *vdev)
312	{
313	int err;
296f96fc RR	314	struct net_device *dev;
296f96fc RR	315	struct virtnet_info *vi;
296f96fc RR	316
	317	/* Allocate ourselves a network device with room for our info */
	318	dev = alloc_etherdev(sizeof(struct virtnet_info));
	319	if (!dev)
	320	return -ENOMEM;
	321
	322	/* Set up network device as normal. */
	323	ether_setup(dev);
	324	dev->open = virtnet_open;
	325	dev->stop = virtnet_close;
	326	dev->hard_start_xmit = start_xmit;
	327	dev->features = NETIF_F_HIGHDMA;
	328	SET_NETDEV_DEV(dev, &vdev->dev);
	329
	330	/* Do we support "hardware" checksums? */
a586d4f6	331	if (vdev->config->feature(vdev, VIRTIO_NET_F_NO_CSUM)) {
296f96fc RR	332	/* This opens up the world of extra features. */
296f96fc RR	333	dev->features \|= NETIF_F_HW_CSUM\|NETIF_F_SG\|NETIF_F_FRAGLIST;
a586d4f6	334	if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4))
296f96fc	335	dev->features \|= NETIF_F_TSO;
a586d4f6	336	if (vdev->config->feature(vdev, VIRTIO_NET_F_UFO))
296f96fc	337	dev->features \|= NETIF_F_UFO;
a586d4f6	338	if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4_ECN))
296f96fc	339	dev->features \|= NETIF_F_TSO_ECN;
a586d4f6	340	if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO6))
296f96fc RR	341	dev->features \|= NETIF_F_TSO6;
	342	}
	343
	344	/* Configuration may specify what MAC to use. Otherwise random. */
a586d4f6 RR	345	if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
	346	vdev->config->get(vdev,
	347	offsetof(struct virtio_net_config, mac),
	348	dev->dev_addr, dev->addr_len);
296f96fc RR	349	} else
	350	random_ether_addr(dev->dev_addr);
	351
	352	/* Set up our device-specific information */
	353	vi = netdev_priv(dev);
	354	netif_napi_add(dev, &vi->napi, virtnet_poll, 16);
	355	vi->dev = dev;
	356	vi->vdev = vdev;
	357
	358	/* We expect two virtqueues, receive then send. */
a586d4f6	359	vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
296f96fc RR	360	if (IS_ERR(vi->rvq)) {
	361	err = PTR_ERR(vi->rvq);
	362	goto free;
	363	}
	364
a586d4f6	365	vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
296f96fc RR	366	if (IS_ERR(vi->svq)) {
	367	err = PTR_ERR(vi->svq);
	368	goto free_recv;
	369	}
	370
	371	/* Initialize our empty receive and send queues. */
	372	skb_queue_head_init(&vi->recv);
	373	skb_queue_head_init(&vi->send);
	374
	375	err = register_netdev(dev);
	376	if (err) {
	377	pr_debug("virtio_net: registering device failed\n");
	378	goto free_send;
	379	}
	380	pr_debug("virtnet: registered device %s\n", dev->name);
	381	vdev->priv = vi;
	382	return 0;
	383
	384	free_send:
	385	vdev->config->del_vq(vi->svq);
	386	free_recv:
	387	vdev->config->del_vq(vi->rvq);
	388	free:
	389	free_netdev(dev);
	390	return err;
	391	}
	392
	393	static void virtnet_remove(struct virtio_device *vdev)
	394	{
74b2553f RR	395	struct virtnet_info *vi = vdev->priv;
	396
	397	vdev->config->del_vq(vi->svq);
	398	vdev->config->del_vq(vi->rvq);
	399	unregister_netdev(vi->dev);
	400	free_netdev(vi->dev);
296f96fc RR	401	}
	402
	403	static struct virtio_device_id id_table[] = {
	404	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
	405	{ 0 },
	406	};
	407
	408	static struct virtio_driver virtio_net = {
	409	.driver.name = KBUILD_MODNAME,
	410	.driver.owner = THIS_MODULE,
	411	.id_table = id_table,
	412	.probe = virtnet_probe,
	413	.remove = __devexit_p(virtnet_remove),
	414	};
	415
	416	static int __init init(void)
	417	{
	418	return register_virtio_driver(&virtio_net);
	419	}
	420
	421	static void __exit fini(void)
	422	{
	423	unregister_virtio_driver(&virtio_net);
	424	}
	425	module_init(init);
	426	module_exit(fini);
	427
	428	MODULE_DEVICE_TABLE(virtio, id_table);
	429	MODULE_DESCRIPTION("Virtio network driver");
	430	MODULE_LICENSE("GPL");