Commit b9fb9ee0 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by David S. Miller
Browse files

macvtap: add GSO/csum offload support 



Added flags field to macvtap_queue to enable/disable processing of
virtio_net_hdr via IFF_VNET_HDR. This flag is checked to prepend virtio_net_hdr
in the receive path and process/skip virtio_net_hdr in the send path.

Original patch by Sridhar, further changes by Arnd.

Signed-off-by: default avatarSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 501c774c

drivers/net/macvtap.c

+182 −24
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <net/net_namespace.h>

#include <net/rtnetlink.h>

#include <net/sock.h>

#include <linux/virtio_net.h>



/*

 * A macvtap queue is the central object of this driver, it connects
@@ -37,6 +38,7 @@ struct macvtap_queue { 
	struct socket sock;

	struct macvlan_dev *vlan;

	struct file *file;

	unsigned int flags;

};



static struct proto macvtap_proto = {
@@ -276,6 +278,7 @@ static int macvtap_open(struct inode *inode, struct file *file) 
	q->sock.ops = &macvtap_socket_ops;

	sock_init_data(&q->sock, &q->sk);

	q->sk.sk_write_space = macvtap_sock_write_space;

	q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;



	err = macvtap_set_queue(dev, file, q);

	if (err)
@@ -318,6 +321,111 @@ out: 
	return mask;

}



static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,

						size_t len, size_t linear,

						int noblock, int *err)

{

	struct sk_buff *skb;



	/* Under a page?  Don't bother with paged skb. */

	if (prepad + len < PAGE_SIZE || !linear)

		linear = len;



	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,

				   err);

	if (!skb)

		return NULL;



	skb_reserve(skb, prepad);

	skb_put(skb, linear);

	skb->data_len = len - linear;

	skb->len += len - linear;



	return skb;

}



/*

 * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should

 * be shared with the tun/tap driver.

 */

static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb,

				     struct virtio_net_hdr *vnet_hdr)

{

	unsigned short gso_type = 0;

	if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {

		switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {

		case VIRTIO_NET_HDR_GSO_TCPV4:

			gso_type = SKB_GSO_TCPV4;

			break;

		case VIRTIO_NET_HDR_GSO_TCPV6:

			gso_type = SKB_GSO_TCPV6;

			break;

		case VIRTIO_NET_HDR_GSO_UDP:

			gso_type = SKB_GSO_UDP;

			break;

		default:

			return -EINVAL;

		}



		if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)

			gso_type |= SKB_GSO_TCP_ECN;



		if (vnet_hdr->gso_size == 0)

			return -EINVAL;

	}



	if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {

		if (!skb_partial_csum_set(skb, vnet_hdr->csum_start,

					  vnet_hdr->csum_offset))

			return -EINVAL;

	}



	if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {

		skb_shinfo(skb)->gso_size = vnet_hdr->gso_size;

		skb_shinfo(skb)->gso_type = gso_type;



		/* Header must be checked, and gso_segs computed. */

		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;

		skb_shinfo(skb)->gso_segs = 0;

	}

	return 0;

}



static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb,

				   struct virtio_net_hdr *vnet_hdr)

{

	memset(vnet_hdr, 0, sizeof(*vnet_hdr));



	if (skb_is_gso(skb)) {

		struct skb_shared_info *sinfo = skb_shinfo(skb);



		/* This is a hint as to how much should be linear. */

		vnet_hdr->hdr_len = skb_headlen(skb);

		vnet_hdr->gso_size = sinfo->gso_size;

		if (sinfo->gso_type & SKB_GSO_TCPV4)

			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;

		else if (sinfo->gso_type & SKB_GSO_TCPV6)

			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;

		else if (sinfo->gso_type & SKB_GSO_UDP)

			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;

		else

			BUG();

		if (sinfo->gso_type & SKB_GSO_TCP_ECN)

			vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;

	} else

		vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;



	if (skb->ip_summed == CHECKSUM_PARTIAL) {

		vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;

		vnet_hdr->csum_start = skb->csum_start -

					skb_headroom(skb);

		vnet_hdr->csum_offset = skb->csum_offset;

	} /* else everything is zero */



	return 0;

}





/* Get packet from user space buffer */

static ssize_t macvtap_get_user(struct macvtap_queue *q,

				const struct iovec *iv, size_t count,
@@ -327,22 +435,53 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, 
	struct macvlan_dev *vlan;

	size_t len = count;

	int err;

	struct virtio_net_hdr vnet_hdr = { 0 };

	int vnet_hdr_len = 0;



	if (q->flags & IFF_VNET_HDR) {

		vnet_hdr_len = sizeof(vnet_hdr);



		err = -EINVAL;

		if ((len -= vnet_hdr_len) < 0)

			goto err;



		err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,

					   vnet_hdr_len);

		if (err < 0)

			goto err;

		if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&

		     vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >

							vnet_hdr.hdr_len)

			vnet_hdr.hdr_len = vnet_hdr.csum_start +

						vnet_hdr.csum_offset + 2;

		err = -EINVAL;

		if (vnet_hdr.hdr_len > len)

			goto err;

	}



	err = -EINVAL;

	if (unlikely(len < ETH_HLEN))

		return -EINVAL;

		goto err;



	skb = sock_alloc_send_skb(&q->sk, NET_IP_ALIGN + len, noblock, &err);

	skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, len, vnet_hdr.hdr_len,

				noblock, &err);

	if (!skb)

		goto err;



	skb_reserve(skb, NET_IP_ALIGN);

	skb_put(skb, count);



	err = skb_copy_datagram_from_iovec(skb, 0, iv, 0, len);

	err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, len);

	if (err)

		goto err;

		goto err_kfree;



	skb_set_network_header(skb, ETH_HLEN);

	skb_reset_mac_header(skb);

	skb->protocol = eth_hdr(skb)->h_proto;



	if (vnet_hdr_len) {

		err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr);

		if (err)

			goto err_kfree;

	}



	rcu_read_lock_bh();

	vlan = rcu_dereference(q->vlan);

	if (vlan)
@@ -353,15 +492,16 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, 


	return count;



err_kfree:

	kfree_skb(skb);



err:

	rcu_read_lock_bh();

	vlan = rcu_dereference(q->vlan);

	if (vlan)

		macvlan_count_rx(q->vlan, 0, false, false);

		netdev_get_tx_queue(vlan->dev, 0)->tx_dropped++;

	rcu_read_unlock_bh();



	kfree_skb(skb);



	return err;

}
@@ -384,10 +524,25 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q, 
{

	struct macvlan_dev *vlan;

	int ret;

	int vnet_hdr_len = 0;



	if (q->flags & IFF_VNET_HDR) {

		struct virtio_net_hdr vnet_hdr;

		vnet_hdr_len = sizeof (vnet_hdr);

		if ((len -= vnet_hdr_len) < 0)

			return -EINVAL;



		ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr);

		if (ret)

			return ret;



		if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, vnet_hdr_len))

			return -EFAULT;

	}



	len = min_t(int, skb->len, len);



	ret = skb_copy_datagram_const_iovec(skb, 0, iv, 0, len);

	ret = skb_copy_datagram_const_iovec(skb, 0, iv, vnet_hdr_len, len);



	rcu_read_lock_bh();

	vlan = rcu_dereference(q->vlan);
@@ -395,7 +550,7 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q, 
		macvlan_count_rx(vlan, len, ret == 0, 0);

	rcu_read_unlock_bh();



	return ret ? ret : len;

	return ret ? ret : (len + vnet_hdr_len);

}



static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
@@ -473,9 +628,14 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, 
		/* ignore the name, just look at flags */

		if (get_user(u, &ifr->ifr_flags))

			return -EFAULT;

		if (u != (IFF_TAP | IFF_NO_PI))

			return -EINVAL;

		return 0;



		ret = 0;

		if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP))

			ret = -EINVAL;

		else

			q->flags = u;



		return ret;



	case TUNGETIFF:

		rcu_read_lock_bh();
@@ -489,13 +649,13 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, 


		ret = 0;

		if (copy_to_user(&ifr->ifr_name, q->vlan->dev->name, IFNAMSIZ) ||

		    put_user((TUN_TAP_DEV | TUN_NO_PI), &ifr->ifr_flags))

		    put_user(q->flags, &ifr->ifr_flags))

			ret = -EFAULT;

		dev_put(vlan->dev);

		return ret;



	case TUNGETFEATURES:

		if (put_user((IFF_TAP | IFF_NO_PI), up))

		if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up))

			return -EFAULT;

		return 0;
@@ -512,12 +672,10 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd, 
			    TUN_F_TSO_ECN | TUN_F_UFO))

			return -EINVAL;



		/* TODO: add support for these, so far we don't

			 support any offload */

		if (arg & (TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |

			 TUN_F_TSO_ECN | TUN_F_UFO))

		/* TODO: only accept frames with the features that

			 got enabled for forwarded frames */

		if (!(q->flags & IFF_VNET_HDR))

			return  -EINVAL;



		return 0;



	default:

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