[GitHub/mt8127/android_kernel_alcatel_ttab.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");
		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;

	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);

	/* All done? */
	if (!skb) {
		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);

	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)
{
	unregister_netdev(vdev->priv);
	free_netdev(vdev->priv);
}

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");
86	skb->ip_summed = CHECKSUM_PARTIAL;
87	skb->csum_start = hdr->csum_start;
88	skb->csum_offset = hdr->csum_offset;
89	if (skb->csum_start > skb->len - 2
90	\|\| skb->csum_offset > skb->len - 2) {
91	if (net_ratelimit())
92	printk(KERN_WARNING "%s: csum=%u/%u len=%u\n",
93	dev->name, skb->csum_start,
94	skb->csum_offset, skb->len);
95	goto frame_err;
96	}
97	}
98
99	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
100	pr_debug("GSO!\n");
101	switch (hdr->gso_type) {
102	case VIRTIO_NET_HDR_GSO_TCPV4:
103	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
104	break;
105	case VIRTIO_NET_HDR_GSO_TCPV4_ECN:
106	skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN;
107	break;
108	case VIRTIO_NET_HDR_GSO_UDP:
109	skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
110	break;
111	case VIRTIO_NET_HDR_GSO_TCPV6:
112	skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
113	break;
114	default:
115	if (net_ratelimit())
116	printk(KERN_WARNING "%s: bad gso type %u.\n",
117	dev->name, hdr->gso_type);
118	goto frame_err;
119	}
120
121	skb_shinfo(skb)->gso_size = hdr->gso_size;
122	if (skb_shinfo(skb)->gso_size == 0) {
123	if (net_ratelimit())
124	printk(KERN_WARNING "%s: zero gso size.\n",
125	dev->name);
126	goto frame_err;
127	}
128
129	/* Header must be checked, and gso_segs computed. */
130	skb_shinfo(skb)->gso_type \|= SKB_GSO_DODGY;
131	skb_shinfo(skb)->gso_segs = 0;
132	}
133
134	netif_receive_skb(skb);
135	return;
136
137	frame_err:
138	dev->stats.rx_frame_errors++;
139	drop:
140	dev_kfree_skb(skb);
141	}
142
143	static void try_fill_recv(struct virtnet_info *vi)
144	{
145	struct sk_buff *skb;
146	struct scatterlist sg[1+MAX_SKB_FRAGS];
147	int num, err;
148
149	for (;;) {
150	skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
151	if (unlikely(!skb))
152	break;
153
154	skb_put(skb, MAX_PACKET_LEN);
155	vnet_hdr_to_sg(sg, skb);
156	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
157	skb_queue_head(&vi->recv, skb);
158
159	err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
160	if (err) {
161	skb_unlink(skb, &vi->recv);
162	kfree_skb(skb);
163	break;
164	}
165	vi->num++;
166	}
167	if (unlikely(vi->num > vi->max))
168	vi->max = vi->num;
169	vi->rvq->vq_ops->kick(vi->rvq);
170	}
171
172	static bool skb_recv_done(struct virtqueue *rvq)
173	{
174	struct virtnet_info *vi = rvq->vdev->priv;
175	netif_rx_schedule(vi->dev, &vi->napi);
176	/* Suppress further interrupts. */
177	return false;
178	}
179
180	static int virtnet_poll(struct napi_struct *napi, int budget)
181	{
182	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
183	struct sk_buff *skb = NULL;
184	unsigned int len, received = 0;
185
186	again:
187	while (received < budget &&
188	(skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
189	__skb_unlink(skb, &vi->recv);
190	receive_skb(vi->dev, skb, len);
191	vi->num--;
192	received++;
193	}
194
195	/* FIXME: If we oom and completely run out of inbufs, we need
196	* to start a timer trying to fill more. */
197	if (vi->num < vi->max / 2)
198	try_fill_recv(vi);
199
200	/* All done? */
201	if (!skb) {
202	netif_rx_complete(vi->dev, napi);
203	if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq))
204	&& netif_rx_reschedule(vi->dev, napi))
205	goto again;
206	}
207
208	return received;
209	}
210
211	static void free_old_xmit_skbs(struct virtnet_info *vi)
212	{
213	struct sk_buff *skb;
214	unsigned int len;
215
216	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
217	pr_debug("Sent skb %p\n", skb);
218	__skb_unlink(skb, &vi->send);
219	vi->dev->stats.tx_bytes += len;
220	vi->dev->stats.tx_packets++;
221	kfree_skb(skb);
222	}
223	}
224
225	static int start_xmit(struct sk_buff skb, struct net_device dev)
226	{
227	struct virtnet_info *vi = netdev_priv(dev);
228	int num, err;
229	struct scatterlist sg[1+MAX_SKB_FRAGS];
230	struct virtio_net_hdr *hdr;
231	const unsigned char dest = ((struct ethhdr )skb->data)->h_dest;
232	DECLARE_MAC_BUF(mac);
233
234	pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
235
236	free_old_xmit_skbs(vi);
237
238	/* Encode metadata header at front. */
239	hdr = skb_vnet_hdr(skb);
240	if (skb->ip_summed == CHECKSUM_PARTIAL) {
241	hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
242	hdr->csum_start = skb->csum_start - skb_headroom(skb);
243	hdr->csum_offset = skb->csum_offset;
244	} else {
245	hdr->flags = 0;
246	hdr->csum_offset = hdr->csum_start = 0;
247	}
248
249	if (skb_is_gso(skb)) {
250	hdr->gso_size = skb_shinfo(skb)->gso_size;
251	if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
252	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN;
253	else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
254	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
255	else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
256	hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
257	else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
258	hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
259	else
260	BUG();
261	} else {
262	hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
263	hdr->gso_size = 0;
264	}
265
266	vnet_hdr_to_sg(sg, skb);
267	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
268	__skb_queue_head(&vi->send, skb);
269	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
270	if (err) {
271	pr_debug("%s: virtio not prepared to send\n", dev->name);
272	skb_unlink(skb, &vi->send);
273	netif_stop_queue(dev);
274	return NETDEV_TX_BUSY;
275	}
276	vi->svq->vq_ops->kick(vi->svq);
277
278	return 0;
279	}
280
281	static int virtnet_open(struct net_device *dev)
282	{
283	struct virtnet_info *vi = netdev_priv(dev);
284
285	try_fill_recv(vi);
286
287	/* If we didn't even get one input buffer, we're useless. */
288	if (vi->num == 0)
289	return -ENOMEM;
290
291	napi_enable(&vi->napi);
292	return 0;
293	}
294
295	static int virtnet_close(struct net_device *dev)
296	{
297	struct virtnet_info *vi = netdev_priv(dev);
298	struct sk_buff *skb;
299
300	napi_disable(&vi->napi);
301
302	/* networking core has neutered skb_xmit_done/skb_recv_done, so don't
303	* worry about races vs. get(). */
304	vi->rvq->vq_ops->shutdown(vi->rvq);
305	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
306	kfree_skb(skb);
307	vi->num--;
308	}
309	vi->svq->vq_ops->shutdown(vi->svq);
310	while ((skb = __skb_dequeue(&vi->send)) != NULL)
311	kfree_skb(skb);
312
313	BUG_ON(vi->num != 0);
314	return 0;
315	}
316
317	static int virtnet_probe(struct virtio_device *vdev)
318	{
319	int err;
320	unsigned int len;
321	struct net_device *dev;
322	struct virtnet_info *vi;
323	void *token;
324
325	/* Allocate ourselves a network device with room for our info */
326	dev = alloc_etherdev(sizeof(struct virtnet_info));
327	if (!dev)
328	return -ENOMEM;
329
330	/* Set up network device as normal. */
331	ether_setup(dev);
332	dev->open = virtnet_open;
333	dev->stop = virtnet_close;
334	dev->hard_start_xmit = start_xmit;
335	dev->features = NETIF_F_HIGHDMA;
336	SET_NETDEV_DEV(dev, &vdev->dev);
337
338	/* Do we support "hardware" checksums? */
339	token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len);
340	if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) {
341	/* This opens up the world of extra features. */
342	dev->features \|= NETIF_F_HW_CSUM\|NETIF_F_SG\|NETIF_F_FRAGLIST;
343	if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4))
344	dev->features \|= NETIF_F_TSO;
345	if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO))
346	dev->features \|= NETIF_F_UFO;
347	if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN))
348	dev->features \|= NETIF_F_TSO_ECN;
349	if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6))
350	dev->features \|= NETIF_F_TSO6;
351	}
352
353	/* Configuration may specify what MAC to use. Otherwise random. */
354	token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len);
355	if (token) {
356	dev->addr_len = len;
357	vdev->config->get(vdev, token, dev->dev_addr, len);
358	} else
359	random_ether_addr(dev->dev_addr);
360
361	/* Set up our device-specific information */
362	vi = netdev_priv(dev);
363	netif_napi_add(dev, &vi->napi, virtnet_poll, 16);
364	vi->dev = dev;
365	vi->vdev = vdev;
366
367	/* We expect two virtqueues, receive then send. */
368	vi->rvq = vdev->config->find_vq(vdev, skb_recv_done);
369	if (IS_ERR(vi->rvq)) {
370	err = PTR_ERR(vi->rvq);
371	goto free;
372	}
373
374	vi->svq = vdev->config->find_vq(vdev, skb_xmit_done);
375	if (IS_ERR(vi->svq)) {
376	err = PTR_ERR(vi->svq);
377	goto free_recv;
378	}
379
380	/* Initialize our empty receive and send queues. */
381	skb_queue_head_init(&vi->recv);
382	skb_queue_head_init(&vi->send);
383
384	err = register_netdev(dev);
385	if (err) {
386	pr_debug("virtio_net: registering device failed\n");
387	goto free_send;
388	}
389	pr_debug("virtnet: registered device %s\n", dev->name);
390	vdev->priv = vi;
391	return 0;
392
393	free_send:
394	vdev->config->del_vq(vi->svq);
395	free_recv:
396	vdev->config->del_vq(vi->rvq);
397	free:
398	free_netdev(dev);
399	return err;
400	}
401
402	static void virtnet_remove(struct virtio_device *vdev)
403	{
404	unregister_netdev(vdev->priv);
405	free_netdev(vdev->priv);
406	}
407
408	static struct virtio_device_id id_table[] = {
409	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
410	{ 0 },
411	};
412
413	static struct virtio_driver virtio_net = {
414	.driver.name = KBUILD_MODNAME,
415	.driver.owner = THIS_MODULE,
416	.id_table = id_table,
417	.probe = virtnet_probe,
418	.remove = __devexit_p(virtnet_remove),
419	};
420
421	static int __init init(void)
422	{
423	return register_virtio_driver(&virtio_net);
424	}
425
426	static void __exit fini(void)
427	{
428	unregister_virtio_driver(&virtio_net);
429	}
430	module_init(init);
431	module_exit(fini);
432
433	MODULE_DEVICE_TABLE(virtio, id_table);
434	MODULE_DESCRIPTION("Virtio network driver");
435	MODULE_LICENSE("GPL");