diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/net/Makefile | 1 | ||||
| -rw-r--r-- | drivers/net/macvtap.c | 581 |
3 files changed, 594 insertions, 0 deletions
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig index cb0e534418e..411e2070311 100644 --- a/drivers/net/Kconfig +++ b/drivers/net/Kconfig @@ -90,6 +90,18 @@ config MACVLAN To compile this driver as a module, choose M here: the module will be called macvlan. +config MACVTAP + tristate "MAC-VLAN based tap driver (EXPERIMENTAL)" + depends on MACVLAN + help + This adds a specialized tap character device driver that is based + on the MAC-VLAN network interface, called macvtap. A macvtap device + can be added in the same way as a macvlan device, using 'type + macvlan', and then be accessed through the tap user space interface. + + To compile this driver as a module, choose M here: the module + will be called macvtap. + config EQUALIZER tristate "EQL (serial line load balancing) support" ---help--- diff --git a/drivers/net/Makefile b/drivers/net/Makefile index 0b763cbe9b1..95958032cd3 100644 --- a/drivers/net/Makefile +++ b/drivers/net/Makefile @@ -169,6 +169,7 @@ obj-$(CONFIG_XEN_NETDEV_FRONTEND) += xen-netfront.o obj-$(CONFIG_DUMMY) += dummy.o obj-$(CONFIG_IFB) += ifb.o obj-$(CONFIG_MACVLAN) += macvlan.o +obj-$(CONFIG_MACVTAP) += macvtap.o obj-$(CONFIG_DE600) += de600.o obj-$(CONFIG_DE620) += de620.o obj-$(CONFIG_LANCE) += lance.o diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c new file mode 100644 index 00000000000..ad1f6ef8930 --- /dev/null +++ b/drivers/net/macvtap.c @@ -0,0 +1,581 @@ +#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> + +/* + * 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; +}; + +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; + +/* + * 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, while in the file_operations, we get it ourselves. + * + * 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. + * + * 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. + */ +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; + q->vlan = vlan; + rcu_assign_pointer(vlan->tap, q); + + q->file = file; + rcu_assign_pointer(file->private_data, q); + +out: + spin_unlock(&macvtap_lock); + return err; +} + +/* + * We must destroy each queue exactly once, when either + * the netdev or the file go away. + * + * 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) +{ + struct macvtap_queue *q; + + spin_lock(&macvtap_lock); + q = rcu_dereference(*qp); + if (!q) { + spin_unlock(&macvtap_lock); + return; + } + + rcu_assign_pointer(q->vlan->tap, NULL); + rcu_assign_pointer(q->file->private_data, NULL); + 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); +} + +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) +{ + rcu_read_lock_bh(); + return rcu_dereference(file->private_data); +} + +static inline void macvtap_file_put_queue(void) +{ + rcu_read_unlock_bh(); +} + +/* + * 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(q->sk.sk_sleep); + 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_sync(sk->sk_sleep); +} + +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; + sock_init_data(&q->sock, &q->sk); + q->sk.sk_allocation = GFP_ATOMIC; /* for now */ + q->sk.sk_write_space = macvtap_sock_write_space; + + 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) +{ + macvtap_del_queue((struct macvtap_queue **)&file->private_data); + return 0; +} + +static unsigned int macvtap_poll(struct file *file, poll_table * wait) +{ + struct macvtap_queue *q = macvtap_file_get_queue(file); + 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: + macvtap_file_put_queue(); + return mask; +} + +/* 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; + size_t len = count; + int err; + + if (unlikely(len < ETH_HLEN)) + return -EINVAL; + + skb = sock_alloc_send_skb(&q->sk, NET_IP_ALIGN + len, noblock, &err); + + if (!skb) { + macvlan_count_rx(q->vlan, 0, false, false); + return err; + } + + skb_reserve(skb, NET_IP_ALIGN); + skb_put(skb, count); + + if (skb_copy_datagram_from_iovec(skb, 0, iv, 0, len)) { + macvlan_count_rx(q->vlan, 0, false, false); + kfree_skb(skb); + return -EFAULT; + } + + skb_set_network_header(skb, ETH_HLEN); + + macvlan_start_xmit(skb, q->vlan->dev); + + return count; +} + +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 = macvtap_file_get_queue(file); + + if (!q) + goto out; + + result = macvtap_get_user(q, iv, iov_length(iv, count), + file->f_flags & O_NONBLOCK); +out: + macvtap_file_put_queue(); + 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 = q->vlan; + int ret; + + len = min_t(int, skb->len, len); + + ret = skb_copy_datagram_const_iovec(skb, 0, iv, 0, len); + + macvlan_count_rx(vlan, len, ret == 0, 0); + + return ret ? ret : len; +} + +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 = macvtap_file_get_queue(file); + + DECLARE_WAITQUEUE(wait, current); + struct sk_buff *skb; + ssize_t len, ret = 0; + + if (!q) { + ret = -ENOLINK; + goto out; + } + + len = iov_length(iv, count); + if (len < 0) { + ret = -EINVAL; + goto out; + } + + 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 (file->f_flags & O_NONBLOCK) { + 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); + +out: + macvtap_file_put_queue(); + 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; + void __user *argp = (void __user *)arg; + struct ifreq __user *ifr = argp; + unsigned int __user *up = argp; + unsigned int u; + char devname[IFNAMSIZ]; + + 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; + + case TUNGETIFF: + q = macvtap_file_get_queue(file); + if (!q) + return -ENOLINK; + memcpy(devname, q->vlan->dev->name, sizeof(devname)); + macvtap_file_put_queue(); + + 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; + + case TUNGETFEATURES: + if (put_user((IFF_TAP | IFF_NO_PI), up)) + return -EFAULT; + return 0; + + case TUNSETSNDBUF: + if (get_user(u, up)) + return -EFAULT; + + q = macvtap_file_get_queue(file); + q->sk.sk_sndbuf = u; + macvtap_file_put_queue(); + 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)) + 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_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"); |