#include <linux/etherdevice.h>
#include <linux/if_macvlan.h>
#include <linux/interrupt.h>
#include <linux/nsproxy.h>
#include <linux/compat.h>
#include <linux/if_tun.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/cache.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#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
* an open character device to a macvlan interface. There can be
* multiple queues on one interface, which map back to queues
* implemented in hardware on the underlying device.
*
* macvtap_proto is used to allocate queues through the sock allocation
* mechanism.
*
* TODO: multiqueue support is currently not implemented, even though
* macvtap is basically prepared for that. We will need to add this
* here as well as in virtio-net and qemu to get line rate on 10gbit
* adapters from a guest.
*/
struct macvtap_queue {
struct sock sk;
struct socket sock;
struct macvlan_dev *vlan;
struct file *file;
unsigned int flags;
};
static struct proto macvtap_proto = {
.name = "macvtap",
.owner = THIS_MODULE,
.obj_size = sizeof (struct macvtap_queue),
};
/*
* Minor number matches netdev->ifindex, so need a potentially
* large value. This also makes it possible to split the
* tap functionality out again in the future by offering it
* from other drivers besides macvtap. As long as every device
* only has one tap, the interface numbers assure that the
* device nodes are unique.
*/
static unsigned int macvtap_major;
#define MACVTAP_NUM_DEVS 65536
static struct class *macvtap_class;
static struct cdev macvtap_cdev;
static const struct proto_ops macvtap_socket_ops;
/*
* RCU usage:
* The macvtap_queue and the macvlan_dev are loosely coupled, the
* pointers from one to the other can only be read while rcu_read_lock
* or macvtap_lock is held.
*
* Both the file and the macvlan_dev hold a reference on the macvtap_queue
* through sock_hold(&q->sk). When the macvlan_dev goes away first,
* q->vlan becomes inaccessible. When the files gets closed,
* macvtap_get_queue() fails.
*
* There may still be references to the struct sock inside of the
* queue from outbound SKBs, but these never reference back to the
* file or the dev. The data structure is freed through __sk_free
* when both our references and any pending SKBs are gone.
*/
static DEFINE_SPINLOCK(macvtap_lock);
/*
* Choose the next free queue, for now there is only one
*/
static int macvtap_set_queue(struct net_device *dev, struct file *file,
struct macvtap_queue *q)
{
struct macvlan_dev *vlan = netdev_priv(dev);
int err = -EBUSY;
spin_lock(&macvtap_lock);
if (rcu_dereference(vlan->tap))
goto out;
err = 0;
rcu_assign_pointer(q->vlan, vlan);
rcu_assign_pointer(vlan->tap, q);
sock_hold(&q->sk);
q->file = file;
file->private_data = q;
out:
spin_unlock(&macvtap_lock);
return err;
}
/*
* The file owning the queue got closed, give up both
* the reference that the files holds as well as the
* one from the macvlan_dev if that still exists.
*
* Using the spinlock makes sure that we don't get
* to the queue again after destroying it.
*/
static void macvtap_put_queue(struct macvtap_queue *q)
{
struct macvlan_dev *vlan;
spin_lock(&macvtap_lock);
vlan = rcu_dereference(q->vlan);
if (vlan) {
rcu_assign_pointer(vlan->tap, NULL);
rcu_assign_pointer(q->vlan, NULL);
sock_put(&q->sk);
}
spin_unlock(&macvtap_lock);
synchronize_rcu();
sock_put(&q->sk);
}
/*
* Since we only support one queue, just dereference the pointer.
*/
static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
struct sk_buff *skb)
{
struct macvlan_dev *vlan = netdev_priv(dev);
return rcu_dereference(vlan->tap);
}
/*
* The net_device is going away, give up the reference
* that it holds on the queue (all the queues one day)
* and safely set the pointer from the queues to NULL.
*/
static void macvtap_del_queues(struct net_device *dev)
{
struct macvlan_dev *vlan = netdev_priv(dev);
struct macvtap_queue *q;
spin_lock(&macvtap_lock);
q = rcu_dereference(vlan->tap);
if (!q) {
spin_unlock(&macvtap_lock);
return;
}
rcu_assign_pointer(vlan->tap, NULL);
rcu_assign_pointer(q->vlan, NULL);
spin_unlock(&macvtap_lock);
synchronize_rcu();
sock_put(&q->sk);
}
/*
* Forward happens for data that gets sent from one macvlan
* endpoint to another one in bridge mode. We just take
* the skb and put it into the receive queue.
*/
static int macvtap_forward(struct net_device *dev, struct sk_buff *skb)
{
struct macvtap_queue *q = macvtap_get_queue(dev, skb);
if (!q)
return -ENOLINK;
skb_queue_tail(&q->sk.sk_receive_queue, skb);
wake_up_interruptible_poll(q->sk.sk_sleep, POLLIN | POLLRDNORM | POLLRDBAND);
return 0;
}
/*
* Receive is for data from the external interface (lowerdev),
* in case of macvtap, we can treat that the same way as
* forward, which macvlan cannot.
*/
static int macvtap_receive(struct sk_buff *skb)
{
skb_push(skb, ETH_HLEN);
return macvtap_forward(skb->dev, skb);
}
static int macvtap_newlink(struct net *src_net,
struct net_device *dev,
struct nlattr *tb[],
struct nlattr *data[])
{
struct device *classdev;
dev_t devt;
int err;
err = macvlan_common_newlink(src_net, dev, tb, data,
macvtap_receive, macvtap_forward);
if (err)
goto out;
devt = MKDEV(MAJOR(macvtap_major), dev->ifindex);
classdev = device_create(macvtap_class, &dev->dev, devt,
dev, "tap%d", dev->ifindex);
if (IS_ERR(classdev)) {
err = PTR_ERR(classdev);
macvtap_del_queues(dev);
}
out:
return err;
}
static void macvtap_dellink(struct net_device *dev,
struct list_head *head)
{
device_destroy(macvtap_class,
MKDEV(MAJOR(macvtap_major), dev->ifindex));
macvtap_del_queues(dev);
macvlan_dellink(dev, head);
}
static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
.kind = "macvtap",
.newlink = macvtap_newlink,
.dellink = macvtap_dellink,
};
static void macvtap_sock_write_space(struct sock *sk)
{
if (!sock_writeable(sk) ||
!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
return;
if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
wake_up_interruptible_poll(sk->sk_sleep, POLLOUT | POLLWRNORM | POLLWRBAND);
}
static int macvtap_open(struct inode *inode, struct file *file)
{
struct net *net = current->nsproxy->net_ns;
struct net_device *dev = dev_get_by_index(net, iminor(inode));
struct macvtap_queue *q;
int err;
err = -ENODEV;
if (!dev)
goto out;
/* check if this is a macvtap device */
err = -EINVAL;
if (dev->rtnl_link_ops != &macvtap_link_ops)
goto out;
err = -ENOMEM;
q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
&macvtap_proto);
if (!q)
goto out;
init_waitqueue_head(&q->sock.wait);
q->sock.type = SOCK_RAW;
q->sock.state = SS_CONNECTED;
q->sock.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)
sock_put(&q->sk);
out:
if (dev)
dev_put(dev);
return err;
}
static int macvtap_release(struct inode *inode, struct file *file)
{
struct macvtap_queue *q = file->private_data;
macvtap_put_queue(q);
return 0;
}
static unsigned int macvtap_poll(struct file *file, poll_table * wait)
{
struct macvtap_queue *q = file->private_data;
unsigned int mask = POLLERR;
if (!q)
goto out;
mask = 0;
poll_wait(file, &q->sock.wait, wait);
if (!skb_queue_empty(&q->sk.sk_receive_queue))
mask |= POLLIN | POLLRDNORM;
if (sock_writeable(&q->sk) ||
(!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) &&
sock_writeable(&q->sk)))
mask |= POLLOUT | POLLWRNORM;
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,
int noblock)
{
struct sk_buff *skb;
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))
goto err;
skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, len, vnet_hdr.hdr_len,
noblock, &err);
if (!skb)
goto err;
err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, len);
if (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)
macvlan_start_xmit(skb, vlan->dev);
else
kfree_skb(skb);
rcu_read_unlock_bh();
return count;
err_kfree:
kfree_skb(skb);
err:
rcu_read_lock_bh();
vlan = rcu_dereference(q->vlan);
if (vlan)
netdev_get_tx_queue(vlan->dev, 0)->tx_dropped++;
rcu_read_unlock_bh();
return err;
}
static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv,
unsigned long count, loff_t pos)
{
struct file *file = iocb->ki_filp;
ssize_t result = -ENOLINK;
struct macvtap_queue *q = file->private_data;
result = macvtap_get_user(q, iv, iov_length(iv, count),
file->f_flags & O_NONBLOCK);
return result;
}
/* Put packet to the user space buffer */
static ssize_t macvtap_put_user(struct macvtap_queue *q,
const struct sk_buff *skb,
const struct iovec *iv, int len)
{
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, vnet_hdr_len, len);
rcu_read_lock_bh();
vlan = rcu_dereference(q->vlan);
if (vlan)
macvlan_count_rx(vlan, len, ret == 0, 0);
rcu_read_unlock_bh();
return ret ? ret : (len + vnet_hdr_len);
}
static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
const struct iovec *iv, unsigned long len,
int noblock)
{
DECLARE_WAITQUEUE(wait, current);
struct sk_buff *skb;
ssize_t ret = 0;
add_wait_queue(q->sk.sk_sleep, &wait);
while (len) {
current->state = TASK_INTERRUPTIBLE;
/* Read frames from the queue */
skb = skb_dequeue(&q->sk.sk_receive_queue);
if (!skb) {
if (noblock) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
/* Nothing to read, let's sleep */
schedule();
continue;
}
ret = macvtap_put_user(q, skb, iv, len);
kfree_skb(skb);
break;
}
current->state = TASK_RUNNING;
remove_wait_queue(q->sk.sk_sleep, &wait);
return ret;
}
static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
unsigned long count, loff_t pos)
{
struct file *file = iocb->ki_filp;
struct macvtap_queue *q = file->private_data;
ssize_t len, ret = 0;
len = iov_length(iv, count);
if (len < 0) {
ret = -EINVAL;
goto out;
}
ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK);
ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
out:
return ret;
}
/*
* provide compatibility with generic tun/tap interface
*/
static long macvtap_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct macvtap_queue *q = file->private_data;
struct macvlan_dev *vlan;
void __user *argp = (void __user *)arg;
struct ifreq __user *ifr = argp;
unsigned int __user *up = argp;
unsigned int u;
int ret;
switch (cmd) {
case TUNSETIFF:
/* ignore the name, just look at flags */
if (get_user(u, &ifr->ifr_flags))
return -EFAULT;
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();
vlan = rcu_dereference(q->vlan);
if (vlan)
dev_hold(vlan->dev);
rcu_read_unlock_bh();
if (!vlan)
return -ENOLINK;
ret = 0;
if (copy_to_user(&ifr->ifr_name, q->vlan->dev->name, IFNAMSIZ) ||
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 | IFF_VNET_HDR, up))
return -EFAULT;
return 0;
case TUNSETSNDBUF:
if (get_user(u, up))
return -EFAULT;
q->sk.sk_sndbuf = u;
return 0;
case TUNSETOFFLOAD:
/* let the user check for future flags */
if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
TUN_F_TSO_ECN | TUN_F_UFO))
return -EINVAL;
/* TODO: only accept frames with the features that
got enabled for forwarded frames */
if (!(q->flags & IFF_VNET_HDR))
return -EINVAL;
return 0;
default:
return -EINVAL;
}
}
#ifdef CONFIG_COMPAT
static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif
static const struct file_operations macvtap_fops = {
.owner = THIS_MODULE,
.open = macvtap_open,
.release = macvtap_release,
.aio_read = macvtap_aio_read,
.aio_write = macvtap_aio_write,
.poll = macvtap_poll,
.llseek = no_llseek,
.unlocked_ioctl = macvtap_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = macvtap_compat_ioctl,
#endif
};
static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t total_len)
{
struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
return macvtap_get_user(q, m->msg_iov, total_len,
m->msg_flags & MSG_DONTWAIT);
}
static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t total_len,
int flags)
{
struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
int ret;
if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
return -EINVAL;
ret = macvtap_do_read(q, iocb, m->msg_iov, total_len,
flags & MSG_DONTWAIT);
if (ret > total_len) {
m->msg_flags |= MSG_TRUNC;
ret = flags & MSG_TRUNC ? ret : total_len;
}
return ret;
}
/* Ops structure to mimic raw sockets with tun */
static const struct proto_ops macvtap_socket_ops = {
.sendmsg = macvtap_sendmsg,
.recvmsg = macvtap_recvmsg,
};
/* Get an underlying socket object from tun file. Returns error unless file is
* attached to a device. The returned object works like a packet socket, it
* can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
* holding a reference to the file for as long as the socket is in use. */
struct socket *macvtap_get_socket(struct file *file)
{
struct macvtap_queue *q;
if (file->f_op != &macvtap_fops)
return ERR_PTR(-EINVAL);
q = file->private_data;
if (!q)
return ERR_PTR(-EBADFD);
return &q->sock;
}
EXPORT_SYMBOL_GPL(macvtap_get_socket);
static int macvtap_init(void)
{
int err;
err = alloc_chrdev_region(&macvtap_major, 0,
MACVTAP_NUM_DEVS, "macvtap");
if (err)
goto out1;
cdev_init(&macvtap_cdev, &macvtap_fops);
err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
if (err)
goto out2;
macvtap_class = class_create(THIS_MODULE, "macvtap");
if (IS_ERR(macvtap_class)) {
err = PTR_ERR(macvtap_class);
goto out3;
}
err = macvlan_link_register(&macvtap_link_ops);
if (err)
goto out4;
return 0;
out4:
class_unregister(macvtap_class);
out3:
cdev_del(&macvtap_cdev);
out2:
unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
out1:
return err;
}
module_init(macvtap_init);
static void macvtap_exit(void)
{
rtnl_link_unregister(&macvtap_link_ops);
class_unregister(macvtap_class);
cdev_del(&macvtap_cdev);
unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
}
module_exit(macvtap_exit);
MODULE_ALIAS_RTNL_LINK("macvtap");
MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
MODULE_LICENSE("GPL");
