#include <linux/cache.h>
#include <linux/sched.h>
#include <linux/types.h>
+#include <linux/slab.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/cdev.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
struct socket sock;
struct macvlan_dev *vlan;
struct file *file;
+ unsigned int flags;
};
static struct proto macvtap_proto = {
static struct class *macvtap_class;
static struct cdev macvtap_cdev;
+static const struct proto_ops macvtap_socket_ops;
+
/*
* RCU usage:
- * The macvtap_queue is referenced both from the chardev struct file
- * and from the struct macvlan_dev using rcu_read_lock.
- *
- * We never actually update the contents of a macvtap_queue atomically
- * with RCU but it is used for race-free destruction of a queue when
- * either the file or the macvlan_dev goes away. Pointers back to
- * the dev and the file are implicitly valid as long as the queue
- * exists.
- *
- * The callbacks from macvlan are always done with rcu_read_lock held
- * already. For calls from file_operations, we use the rcu_read_lock_bh
- * to get a reference count on the socket and the device.
+ * 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.
*
- * When destroying a queue, we remove the pointers from the file and
- * from the dev and then synchronize_rcu to make sure no thread is
- * still using the queue. 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.
+ * 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.
*
- * macvtap_lock is only used to prevent multiple concurrent open()
- * calls to assign a new vlan->tap pointer. It could be moved into
- * the macvlan_dev itself but is extremely rarely used.
+ * 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);
goto out;
err = 0;
- q->vlan = vlan;
+ rcu_assign_pointer(q->vlan, vlan);
rcu_assign_pointer(vlan->tap, q);
+ sock_hold(&q->sk);
q->file = file;
- rcu_assign_pointer(file->private_data, q);
+ file->private_data = q;
out:
spin_unlock(&macvtap_lock);
}
/*
- * We must destroy each queue exactly once, when either
- * the netdev or the file go away.
+ * 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.
- *
- * synchronize_rcu serializes with the packet flow
- * that uses rcu_read_lock.
*/
-static void macvtap_del_queue(struct macvtap_queue **qp)
+static void macvtap_put_queue(struct macvtap_queue *q)
{
- struct macvtap_queue *q;
+ struct macvlan_dev *vlan;
spin_lock(&macvtap_lock);
- q = rcu_dereference(*qp);
- if (!q) {
- spin_unlock(&macvtap_lock);
- return;
+ vlan = rcu_dereference(q->vlan);
+ if (vlan) {
+ rcu_assign_pointer(vlan->tap, NULL);
+ rcu_assign_pointer(q->vlan, NULL);
+ sock_put(&q->sk);
}
- rcu_assign_pointer(q->vlan->tap, NULL);
- rcu_assign_pointer(q->file->private_data, NULL);
spin_unlock(&macvtap_lock);
synchronize_rcu();
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);
- macvtap_del_queue(&vlan->tap);
-}
-
-static inline struct macvtap_queue *macvtap_file_get_queue(struct file *file)
-{
struct macvtap_queue *q;
- rcu_read_lock_bh();
- q = rcu_dereference(file->private_data);
- if (q) {
- sock_hold(&q->sk);
- dev_hold(q->vlan->dev);
+
+ spin_lock(&macvtap_lock);
+ q = rcu_dereference(vlan->tap);
+ if (!q) {
+ spin_unlock(&macvtap_lock);
+ return;
}
- rcu_read_unlock_bh();
- return q;
-}
-static inline void macvtap_file_put_queue(struct macvtap_queue *q)
-{
+ rcu_assign_pointer(vlan->tap, NULL);
+ rcu_assign_pointer(q->vlan, NULL);
+ spin_unlock(&macvtap_lock);
+
+ synchronize_rcu();
sock_put(&q->sk);
- dev_put(q->vlan->dev);
}
/*
return -ENOLINK;
skb_queue_tail(&q->sk.sk_receive_queue, skb);
- wake_up(q->sk.sk_sleep);
+ wake_up_interruptible_poll(q->sk.sk_sleep, POLLIN | POLLRDNORM | POLLRDBAND);
return 0;
}
return;
if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
- wake_up_interruptible_sync(sk->sk_sleep);
+ wake_up_interruptible_poll(sk->sk_sleep, POLLOUT | POLLWRNORM | POLLWRBAND);
}
static int macvtap_open(struct inode *inode, struct file *file)
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_allocation = GFP_ATOMIC; /* for now */
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)
static int macvtap_release(struct inode *inode, struct file *file)
{
- macvtap_del_queue((struct macvtap_queue **)&file->private_data);
+ 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 = macvtap_file_get_queue(file);
+ struct macvtap_queue *q = file->private_data;
unsigned int mask = POLLERR;
if (!q)
sock_writeable(&q->sk)))
mask |= POLLOUT | POLLWRNORM;
- macvtap_file_put_queue(q);
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))
- 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;
- if (!skb) {
- macvlan_count_rx(q->vlan, 0, false, false);
- return 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;
- skb_reserve(skb, NET_IP_ALIGN);
- skb_put(skb, count);
+ if (vnet_hdr_len) {
+ err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr);
+ if (err)
+ goto err_kfree;
+ }
- if (skb_copy_datagram_from_iovec(skb, 0, iv, 0, len)) {
- macvlan_count_rx(q->vlan, 0, false, false);
+ rcu_read_lock_bh();
+ vlan = rcu_dereference(q->vlan);
+ if (vlan)
+ macvlan_start_xmit(skb, vlan->dev);
+ else
kfree_skb(skb);
- return -EFAULT;
- }
+ rcu_read_unlock_bh();
- skb_set_network_header(skb, ETH_HLEN);
+ return count;
- macvlan_start_xmit(skb, q->vlan->dev);
+err_kfree:
+ kfree_skb(skb);
- return count;
+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,
{
struct file *file = iocb->ki_filp;
ssize_t result = -ENOLINK;
- struct macvtap_queue *q = macvtap_file_get_queue(file);
-
- if (!q)
- goto out;
+ struct macvtap_queue *q = file->private_data;
result = macvtap_get_user(q, iv, iov_length(iv, count),
file->f_flags & O_NONBLOCK);
- macvtap_file_put_queue(q);
-out:
return result;
}
const struct sk_buff *skb,
const struct iovec *iv, int len)
{
- struct macvlan_dev *vlan = q->vlan;
+ 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);
- macvlan_count_rx(vlan, len, ret == 0, 0);
+ 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;
+ return ret ? ret : (len + vnet_hdr_len);
}
-static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
- unsigned long count, loff_t pos)
+static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
+ const struct iovec *iv, unsigned long len,
+ int noblock)
{
- struct file *file = iocb->ki_filp;
- struct macvtap_queue *q = macvtap_file_get_queue(file);
-
DECLARE_WAITQUEUE(wait, current);
struct sk_buff *skb;
- ssize_t len, ret = 0;
-
- if (!q)
- return -ENOLINK;
-
- len = iov_length(iv, count);
- if (len < 0) {
- ret = -EINVAL;
- goto out;
- }
+ ssize_t ret = 0;
add_wait_queue(q->sk.sk_sleep, &wait);
while (len) {
/* Read frames from the queue */
skb = skb_dequeue(&q->sk.sk_receive_queue);
if (!skb) {
- if (file->f_flags & O_NONBLOCK) {
+ if (noblock) {
ret = -EAGAIN;
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:
- macvtap_file_put_queue(q);
return ret;
}
static long macvtap_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
- struct macvtap_queue *q;
+ 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;
- char devname[IFNAMSIZ];
+ int ret;
switch (cmd) {
case TUNSETIFF:
/* 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:
- q = macvtap_file_get_queue(file);
- if (!q)
+ rcu_read_lock_bh();
+ vlan = rcu_dereference(q->vlan);
+ if (vlan)
+ dev_hold(vlan->dev);
+ rcu_read_unlock_bh();
+
+ if (!vlan)
return -ENOLINK;
- memcpy(devname, q->vlan->dev->name, sizeof(devname));
- macvtap_file_put_queue(q);
+ 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))
- return -EFAULT;
- return 0;
+ 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;
if (get_user(u, up))
return -EFAULT;
- q = macvtap_file_get_queue(file);
- if (!q)
- return -ENOLINK;
q->sk.sk_sndbuf = u;
- macvtap_file_put_queue(q);
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: 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))
+ 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:
#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;
projects / mv-sheeva.git / blobdiff