diff options
Diffstat (limited to 'drivers/net/macvtap.c')
| -rw-r--r-- | drivers/net/macvtap.c | 803 |
1 files changed, 803 insertions, 0 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c new file mode 100644 index 00000000000..55ceae09738 --- /dev/null +++ b/drivers/net/macvtap.c @@ -0,0 +1,803 @@ +#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"); |