diff options
Diffstat (limited to 'drivers/net/tap.c')
| -rw-r--r-- | drivers/net/tap.c | 1186 |
1 files changed, 1186 insertions, 0 deletions
diff --git a/drivers/net/tap.c b/drivers/net/tap.c new file mode 100644 index 000000000000..6f6228e4fd3f --- /dev/null +++ b/drivers/net/tap.c @@ -0,0 +1,1186 @@ +#include <linux/etherdevice.h> +#include <linux/if_macvlan.h> +#include <linux/if_vlan.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/slab.h> +#include <linux/wait.h> +#include <linux/cdev.h> +#include <linux/idr.h> +#include <linux/fs.h> +#include <linux/uio.h> + +#include <net/net_namespace.h> +#include <net/rtnetlink.h> +#include <net/sock.h> +#include <linux/virtio_net.h> +#include <linux/skb_array.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. + * + */ +struct macvtap_queue { + struct sock sk; + struct socket sock; + struct socket_wq wq; + int vnet_hdr_sz; + struct macvlan_dev __rcu *vlan; + struct file *file; + unsigned int flags; + u16 queue_index; + bool enabled; + struct list_head next; + struct skb_array skb_array; +}; + +#define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE) + +#define MACVTAP_VNET_LE 0x80000000 +#define MACVTAP_VNET_BE 0x40000000 + +#ifdef CONFIG_TUN_VNET_CROSS_LE +static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q) +{ + return q->flags & MACVTAP_VNET_BE ? false : + virtio_legacy_is_little_endian(); +} + +static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *sp) +{ + int s = !!(q->flags & MACVTAP_VNET_BE); + + if (put_user(s, sp)) + return -EFAULT; + + return 0; +} + +static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *sp) +{ + int s; + + if (get_user(s, sp)) + return -EFAULT; + + if (s) + q->flags |= MACVTAP_VNET_BE; + else + q->flags &= ~MACVTAP_VNET_BE; + + return 0; +} +#else +static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q) +{ + return virtio_legacy_is_little_endian(); +} + +static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *argp) +{ + return -EINVAL; +} + +static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *argp) +{ + return -EINVAL; +} +#endif /* CONFIG_TUN_VNET_CROSS_LE */ + +static inline bool macvtap_is_little_endian(struct macvtap_queue *q) +{ + return q->flags & MACVTAP_VNET_LE || + macvtap_legacy_is_little_endian(q); +} + +static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) +{ + return __virtio16_to_cpu(macvtap_is_little_endian(q), val); +} + +static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val) +{ + return __cpu_to_virtio16(macvtap_is_little_endian(q), val); +} + +static struct proto macvtap_proto = { + .name = "macvtap", + .owner = THIS_MODULE, + .obj_size = sizeof (struct macvtap_queue), +}; + +#define MACVTAP_NUM_DEVS (1U << MINORBITS) +static DEFINE_MUTEX(minor_lock); +DEFINE_IDR(minor_idr); + +#define GOODCOPY_LEN 128 + +static const struct proto_ops macvtap_socket_ops; + +#define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO) +#define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG | NETIF_F_FRAGLIST) + +static struct macvlan_dev *macvtap_get_vlan_rcu(const struct net_device *dev) +{ + return rcu_dereference(dev->rx_handler_data); +} + +/* + * 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 rtnl 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 int macvtap_enable_queue(struct net_device *dev, struct file *file, + struct macvtap_queue *q) +{ + struct macvlan_dev *vlan = netdev_priv(dev); + int err = -EINVAL; + + ASSERT_RTNL(); + + if (q->enabled) + goto out; + + err = 0; + rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); + q->queue_index = vlan->numvtaps; + q->enabled = true; + + vlan->numvtaps++; +out: + return err; +} + +/* Requires RTNL */ +static int macvtap_set_queue(struct net_device *dev, struct file *file, + struct macvtap_queue *q) +{ + struct macvlan_dev *vlan = netdev_priv(dev); + + if (vlan->numqueues == MAX_MACVTAP_QUEUES) + return -EBUSY; + + rcu_assign_pointer(q->vlan, vlan); + rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); + sock_hold(&q->sk); + + q->file = file; + q->queue_index = vlan->numvtaps; + q->enabled = true; + file->private_data = q; + list_add_tail(&q->next, &vlan->queue_list); + + vlan->numvtaps++; + vlan->numqueues++; + + return 0; +} + +static int macvtap_disable_queue(struct macvtap_queue *q) +{ + struct macvlan_dev *vlan; + struct macvtap_queue *nq; + + ASSERT_RTNL(); + if (!q->enabled) + return -EINVAL; + + vlan = rtnl_dereference(q->vlan); + + if (vlan) { + int index = q->queue_index; + BUG_ON(index >= vlan->numvtaps); + nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]); + nq->queue_index = index; + + rcu_assign_pointer(vlan->taps[index], nq); + RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL); + q->enabled = false; + + vlan->numvtaps--; + } + + return 0; +} + +/* + * 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; + + rtnl_lock(); + vlan = rtnl_dereference(q->vlan); + + if (vlan) { + if (q->enabled) + BUG_ON(macvtap_disable_queue(q)); + + vlan->numqueues--; + RCU_INIT_POINTER(q->vlan, NULL); + sock_put(&q->sk); + list_del_init(&q->next); + } + + rtnl_unlock(); + + synchronize_rcu(); + sock_put(&q->sk); +} + +/* + * Select a queue based on the rxq of the device on which this packet + * arrived. If the incoming device is not mq, calculate a flow hash + * to select a queue. If all fails, find the first available queue. + * Cache vlan->numvtaps since it can become zero during the execution + * of this function. + */ +static struct macvtap_queue *macvtap_get_queue(struct net_device *dev, + struct sk_buff *skb) +{ + struct macvlan_dev *vlan = netdev_priv(dev); + struct macvtap_queue *tap = NULL; + /* Access to taps array is protected by rcu, but access to numvtaps + * isn't. Below we use it to lookup a queue, but treat it as a hint + * and validate that the result isn't NULL - in case we are + * racing against queue removal. + */ + int numvtaps = ACCESS_ONCE(vlan->numvtaps); + __u32 rxq; + + if (!numvtaps) + goto out; + + if (numvtaps == 1) + goto single; + + /* Check if we can use flow to select a queue */ + rxq = skb_get_hash(skb); + if (rxq) { + tap = rcu_dereference(vlan->taps[rxq % numvtaps]); + goto out; + } + + if (likely(skb_rx_queue_recorded(skb))) { + rxq = skb_get_rx_queue(skb); + + while (unlikely(rxq >= numvtaps)) + rxq -= numvtaps; + + tap = rcu_dereference(vlan->taps[rxq]); + goto out; + } + +single: + tap = rcu_dereference(vlan->taps[0]); +out: + return tap; +} + +/* + * The net_device is going away, give up the reference + * that it holds on all queues and safely set the pointer + * from the queues to NULL. + */ +void macvtap_del_queues(struct net_device *dev) +{ + struct macvlan_dev *vlan = netdev_priv(dev); + struct macvtap_queue *q, *tmp; + + ASSERT_RTNL(); + list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) { + list_del_init(&q->next); + RCU_INIT_POINTER(q->vlan, NULL); + if (q->enabled) + vlan->numvtaps--; + vlan->numqueues--; + sock_put(&q->sk); + } + BUG_ON(vlan->numvtaps); + BUG_ON(vlan->numqueues); + /* guarantee that any future macvtap_set_queue will fail */ + vlan->numvtaps = MAX_MACVTAP_QUEUES; +} + +rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb) +{ + struct sk_buff *skb = *pskb; + struct net_device *dev = skb->dev; + struct macvlan_dev *vlan; + struct macvtap_queue *q; + netdev_features_t features = TAP_FEATURES; + + vlan = macvtap_get_vlan_rcu(dev); + if (!vlan) + return RX_HANDLER_PASS; + + q = macvtap_get_queue(dev, skb); + if (!q) + return RX_HANDLER_PASS; + + if (__skb_array_full(&q->skb_array)) + goto drop; + + skb_push(skb, ETH_HLEN); + + /* Apply the forward feature mask so that we perform segmentation + * according to users wishes. This only works if VNET_HDR is + * enabled. + */ + if (q->flags & IFF_VNET_HDR) + features |= vlan->tap_features; + if (netif_needs_gso(skb, features)) { + struct sk_buff *segs = __skb_gso_segment(skb, features, false); + + if (IS_ERR(segs)) + goto drop; + + if (!segs) { + if (skb_array_produce(&q->skb_array, skb)) + goto drop; + goto wake_up; + } + + consume_skb(skb); + while (segs) { + struct sk_buff *nskb = segs->next; + + segs->next = NULL; + if (skb_array_produce(&q->skb_array, segs)) { + kfree_skb(segs); + kfree_skb_list(nskb); + break; + } + segs = nskb; + } + } else { + /* If we receive a partial checksum and the tap side + * doesn't support checksum offload, compute the checksum. + * Note: it doesn't matter which checksum feature to + * check, we either support them all or none. + */ + if (skb->ip_summed == CHECKSUM_PARTIAL && + !(features & NETIF_F_CSUM_MASK) && + skb_checksum_help(skb)) + goto drop; + if (skb_array_produce(&q->skb_array, skb)) + goto drop; + } + +wake_up: + wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND); + return RX_HANDLER_CONSUMED; + +drop: + /* Count errors/drops only here, thus don't care about args. */ + macvlan_count_rx(vlan, 0, 0, 0); + kfree_skb(skb); + return RX_HANDLER_CONSUMED; +} + +int macvtap_get_minor(struct macvlan_dev *vlan) +{ + int retval = -ENOMEM; + + mutex_lock(&minor_lock); + retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL); + if (retval >= 0) { + vlan->minor = retval; + } else if (retval == -ENOSPC) { + netdev_err(vlan->dev, "Too many macvtap devices\n"); + retval = -EINVAL; + } + mutex_unlock(&minor_lock); + return retval < 0 ? retval : 0; +} + +void macvtap_free_minor(struct macvlan_dev *vlan) +{ + mutex_lock(&minor_lock); + if (vlan->minor) { + idr_remove(&minor_idr, vlan->minor); + vlan->minor = 0; + } + mutex_unlock(&minor_lock); +} + +static struct net_device *dev_get_by_macvtap_minor(int minor) +{ + struct net_device *dev = NULL; + struct macvlan_dev *vlan; + + mutex_lock(&minor_lock); + vlan = idr_find(&minor_idr, minor); + if (vlan) { + dev = vlan->dev; + dev_hold(dev); + } + mutex_unlock(&minor_lock); + return dev; +} + +static void macvtap_sock_write_space(struct sock *sk) +{ + wait_queue_head_t *wqueue; + + if (!sock_writeable(sk) || + !test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags)) + return; + + wqueue = sk_sleep(sk); + if (wqueue && waitqueue_active(wqueue)) + wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND); +} + +static void macvtap_sock_destruct(struct sock *sk) +{ + struct macvtap_queue *q = container_of(sk, struct macvtap_queue, sk); + + skb_array_cleanup(&q->skb_array); +} + +static int macvtap_open(struct inode *inode, struct file *file) +{ + struct net *net = current->nsproxy->net_ns; + struct net_device *dev; + struct macvtap_queue *q; + int err = -ENODEV; + + rtnl_lock(); + dev = dev_get_by_macvtap_minor(iminor(inode)); + if (!dev) + goto err; + + err = -ENOMEM; + q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, + &macvtap_proto, 0); + if (!q) + goto err; + + RCU_INIT_POINTER(q->sock.wq, &q->wq); + init_waitqueue_head(&q->wq.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->sk.sk_destruct = macvtap_sock_destruct; + q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP; + q->vnet_hdr_sz = sizeof(struct virtio_net_hdr); + + /* + * so far only KVM virtio_net uses macvtap, enable zero copy between + * guest kernel and host kernel when lower device supports zerocopy + * + * The macvlan supports zerocopy iff the lower device supports zero + * copy so we don't have to look at the lower device directly. + */ + if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG)) + sock_set_flag(&q->sk, SOCK_ZEROCOPY); + + err = -ENOMEM; + if (skb_array_init(&q->skb_array, dev->tx_queue_len, GFP_KERNEL)) + goto err_array; + + err = macvtap_set_queue(dev, file, q); + if (err) + goto err_queue; + + dev_put(dev); + + rtnl_unlock(); + return err; + +err_queue: + skb_array_cleanup(&q->skb_array); +err_array: + sock_put(&q->sk); +err: + if (dev) + dev_put(dev); + + rtnl_unlock(); + 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->wq.wait, wait); + + if (!skb_array_empty(&q->skb_array)) + mask |= POLLIN | POLLRDNORM; + + if (sock_writeable(&q->sk) || + (!test_and_set_bit(SOCKWQ_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, 0); + if (!skb) + return NULL; + + skb_reserve(skb, prepad); + skb_put(skb, linear); + skb->data_len = len - linear; + skb->len += len - linear; + + return skb; +} + +/* Neighbour code has some assumptions on HH_DATA_MOD alignment */ +#define MACVTAP_RESERVE HH_DATA_OFF(ETH_HLEN) + +/* Get packet from user space buffer */ +static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, + struct iov_iter *from, int noblock) +{ + int good_linear = SKB_MAX_HEAD(MACVTAP_RESERVE); + struct sk_buff *skb; + struct macvlan_dev *vlan; + unsigned long total_len = iov_iter_count(from); + unsigned long len = total_len; + int err; + struct virtio_net_hdr vnet_hdr = { 0 }; + int vnet_hdr_len = 0; + int copylen = 0; + int depth; + bool zerocopy = false; + size_t linear; + + if (q->flags & IFF_VNET_HDR) { + vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); + + err = -EINVAL; + if (len < vnet_hdr_len) + goto err; + len -= vnet_hdr_len; + + err = -EFAULT; + if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from)) + goto err; + iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr)); + if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && + macvtap16_to_cpu(q, vnet_hdr.csum_start) + + macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2 > + macvtap16_to_cpu(q, vnet_hdr.hdr_len)) + vnet_hdr.hdr_len = cpu_to_macvtap16(q, + macvtap16_to_cpu(q, vnet_hdr.csum_start) + + macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2); + err = -EINVAL; + if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > len) + goto err; + } + + err = -EINVAL; + if (unlikely(len < ETH_HLEN)) + goto err; + + if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) { + struct iov_iter i; + + copylen = vnet_hdr.hdr_len ? + macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN; + if (copylen > good_linear) + copylen = good_linear; + else if (copylen < ETH_HLEN) + copylen = ETH_HLEN; + linear = copylen; + i = *from; + iov_iter_advance(&i, copylen); + if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) + zerocopy = true; + } + + if (!zerocopy) { + copylen = len; + linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len); + if (linear > good_linear) + linear = good_linear; + else if (linear < ETH_HLEN) + linear = ETH_HLEN; + } + + skb = macvtap_alloc_skb(&q->sk, MACVTAP_RESERVE, copylen, + linear, noblock, &err); + if (!skb) + goto err; + + if (zerocopy) + err = zerocopy_sg_from_iter(skb, from); + else + err = skb_copy_datagram_from_iter(skb, 0, from, 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 = virtio_net_hdr_to_skb(skb, &vnet_hdr, + macvtap_is_little_endian(q)); + if (err) + goto err_kfree; + } + + skb_probe_transport_header(skb, ETH_HLEN); + + /* Move network header to the right position for VLAN tagged packets */ + if ((skb->protocol == htons(ETH_P_8021Q) || + skb->protocol == htons(ETH_P_8021AD)) && + __vlan_get_protocol(skb, skb->protocol, &depth) != 0) + skb_set_network_header(skb, depth); + + rcu_read_lock(); + vlan = rcu_dereference(q->vlan); + /* copy skb_ubuf_info for callback when skb has no error */ + if (zerocopy) { + skb_shinfo(skb)->destructor_arg = m->msg_control; + skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; + skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; + } else if (m && m->msg_control) { + struct ubuf_info *uarg = m->msg_control; + uarg->callback(uarg, false); + } + + if (vlan) { + skb->dev = vlan->dev; + dev_queue_xmit(skb); + } else { + kfree_skb(skb); + } + rcu_read_unlock(); + + return total_len; + +err_kfree: + kfree_skb(skb); + +err: + rcu_read_lock(); + vlan = rcu_dereference(q->vlan); + if (vlan) + this_cpu_inc(vlan->pcpu_stats->tx_dropped); + rcu_read_unlock(); + + return err; +} + +static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct macvtap_queue *q = file->private_data; + + return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK); +} + +/* Put packet to the user space buffer */ +static ssize_t macvtap_put_user(struct macvtap_queue *q, + const struct sk_buff *skb, + struct iov_iter *iter) +{ + int ret; + int vnet_hdr_len = 0; + int vlan_offset = 0; + int total; + + if (q->flags & IFF_VNET_HDR) { + struct virtio_net_hdr vnet_hdr; + vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); + if (iov_iter_count(iter) < vnet_hdr_len) + return -EINVAL; + + if (virtio_net_hdr_from_skb(skb, &vnet_hdr, + macvtap_is_little_endian(q), true)) + BUG(); + + if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) != + sizeof(vnet_hdr)) + return -EFAULT; + + iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr)); + } + total = vnet_hdr_len; + total += skb->len; + + if (skb_vlan_tag_present(skb)) { + struct { + __be16 h_vlan_proto; + __be16 h_vlan_TCI; + } veth; + veth.h_vlan_proto = skb->vlan_proto; + veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); + + vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); + total += VLAN_HLEN; + + ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); + if (ret || !iov_iter_count(iter)) + goto done; + + ret = copy_to_iter(&veth, sizeof(veth), iter); + if (ret != sizeof(veth) || !iov_iter_count(iter)) + goto done; + } + + ret = skb_copy_datagram_iter(skb, vlan_offset, iter, + skb->len - vlan_offset); + +done: + return ret ? ret : total; +} + +static ssize_t macvtap_do_read(struct macvtap_queue *q, + struct iov_iter *to, + int noblock) +{ + DEFINE_WAIT(wait); + struct sk_buff *skb; + ssize_t ret = 0; + + if (!iov_iter_count(to)) + return 0; + + while (1) { + if (!noblock) + prepare_to_wait(sk_sleep(&q->sk), &wait, + TASK_INTERRUPTIBLE); + + /* Read frames from the queue */ + skb = skb_array_consume(&q->skb_array); + if (skb) + break; + if (noblock) { + ret = -EAGAIN; + break; + } + if (signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + /* Nothing to read, let's sleep */ + schedule(); + } + if (!noblock) + finish_wait(sk_sleep(&q->sk), &wait); + + if (skb) { + ret = macvtap_put_user(q, skb, to); + if (unlikely(ret < 0)) + kfree_skb(skb); + else + consume_skb(skb); + } + return ret; +} + +static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct file *file = iocb->ki_filp; + struct macvtap_queue *q = file->private_data; + ssize_t len = iov_iter_count(to), ret; + + ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK); + ret = min_t(ssize_t, ret, len); + if (ret > 0) + iocb->ki_pos = ret; + return ret; +} + +static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q) +{ + struct macvlan_dev *vlan; + + ASSERT_RTNL(); + vlan = rtnl_dereference(q->vlan); + if (vlan) + dev_hold(vlan->dev); + + return vlan; +} + +static void macvtap_put_vlan(struct macvlan_dev *vlan) +{ + dev_put(vlan->dev); +} + +static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags) +{ + struct macvtap_queue *q = file->private_data; + struct macvlan_dev *vlan; + int ret; + + vlan = macvtap_get_vlan(q); + if (!vlan) + return -EINVAL; + + if (flags & IFF_ATTACH_QUEUE) + ret = macvtap_enable_queue(vlan->dev, file, q); + else if (flags & IFF_DETACH_QUEUE) + ret = macvtap_disable_queue(q); + else + ret = -EINVAL; + + macvtap_put_vlan(vlan); + return ret; +} + +static int set_offload(struct macvtap_queue *q, unsigned long arg) +{ + struct macvlan_dev *vlan; + netdev_features_t features; + netdev_features_t feature_mask = 0; + + vlan = rtnl_dereference(q->vlan); + if (!vlan) + return -ENOLINK; + + features = vlan->dev->features; + + if (arg & TUN_F_CSUM) { + feature_mask = NETIF_F_HW_CSUM; + + if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) { + if (arg & TUN_F_TSO_ECN) + feature_mask |= NETIF_F_TSO_ECN; + if (arg & TUN_F_TSO4) + feature_mask |= NETIF_F_TSO; + if (arg & TUN_F_TSO6) + feature_mask |= NETIF_F_TSO6; + } + + if (arg & TUN_F_UFO) + feature_mask |= NETIF_F_UFO; + } + + /* tun/tap driver inverts the usage for TSO offloads, where + * setting the TSO bit means that the userspace wants to + * accept TSO frames and turning it off means that user space + * does not support TSO. + * For macvtap, we have to invert it to mean the same thing. + * When user space turns off TSO, we turn off GSO/LRO so that + * user-space will not receive TSO frames. + */ + if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO)) + features |= RX_OFFLOADS; + else + features &= ~RX_OFFLOADS; + + /* tap_features are the same as features on tun/tap and + * reflect user expectations. + */ + vlan->tap_features = feature_mask; + vlan->set_features = features; + netdev_update_features(vlan->dev); + + return 0; +} + +/* + * 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 short u; + int __user *sp = argp; + struct sockaddr sa; + int s; + 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 & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP)) + ret = -EINVAL; + else + q->flags = (q->flags & ~MACVTAP_FEATURES) | u; + + return ret; + + case TUNGETIFF: + rtnl_lock(); + vlan = macvtap_get_vlan(q); + if (!vlan) { + rtnl_unlock(); + return -ENOLINK; + } + + ret = 0; + u = q->flags; + if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || + put_user(u, &ifr->ifr_flags)) + ret = -EFAULT; + macvtap_put_vlan(vlan); + rtnl_unlock(); + return ret; + + case TUNSETQUEUE: + if (get_user(u, &ifr->ifr_flags)) + return -EFAULT; + rtnl_lock(); + ret = macvtap_ioctl_set_queue(file, u); + rtnl_unlock(); + return ret; + + case TUNGETFEATURES: + if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up)) + return -EFAULT; + return 0; + + case TUNSETSNDBUF: + if (get_user(s, sp)) + return -EFAULT; + + q->sk.sk_sndbuf = s; + return 0; + + case TUNGETVNETHDRSZ: + s = q->vnet_hdr_sz; + if (put_user(s, sp)) + return -EFAULT; + return 0; + + case TUNSETVNETHDRSZ: + if (get_user(s, sp)) + return -EFAULT; + if (s < (int)sizeof(struct virtio_net_hdr)) + return -EINVAL; + + q->vnet_hdr_sz = s; + return 0; + + case TUNGETVNETLE: + s = !!(q->flags & MACVTAP_VNET_LE); + if (put_user(s, sp)) + return -EFAULT; + return 0; + + case TUNSETVNETLE: + if (get_user(s, sp)) + return -EFAULT; + if (s) + q->flags |= MACVTAP_VNET_LE; + else + q->flags &= ~MACVTAP_VNET_LE; + return 0; + + case TUNGETVNETBE: + return macvtap_get_vnet_be(q, sp); + + case TUNSETVNETBE: + return macvtap_set_vnet_be(q, sp); + + 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; + + rtnl_lock(); + ret = set_offload(q, arg); + rtnl_unlock(); + return ret; + + case SIOCGIFHWADDR: + rtnl_lock(); + vlan = macvtap_get_vlan(q); + if (!vlan) { + rtnl_unlock(); + return -ENOLINK; + } + ret = 0; + u = vlan->dev->type; + if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || + copy_to_user(&ifr->ifr_hwaddr.sa_data, vlan->dev->dev_addr, ETH_ALEN) || + put_user(u, &ifr->ifr_hwaddr.sa_family)) + ret = -EFAULT; + macvtap_put_vlan(vlan); + rtnl_unlock(); + return ret; + + case SIOCSIFHWADDR: + if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa))) + return -EFAULT; + rtnl_lock(); + vlan = macvtap_get_vlan(q); + if (!vlan) { + rtnl_unlock(); + return -ENOLINK; + } + ret = dev_set_mac_address(vlan->dev, &sa); + macvtap_put_vlan(vlan); + rtnl_unlock(); + return ret; + + 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 + +const struct file_operations macvtap_fops = { + .owner = THIS_MODULE, + .open = macvtap_open, + .release = macvtap_release, + .read_iter = macvtap_read_iter, + .write_iter = macvtap_write_iter, + .poll = macvtap_poll, + .llseek = no_llseek, + .unlocked_ioctl = macvtap_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = macvtap_compat_ioctl, +#endif +}; + +static int macvtap_sendmsg(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, &m->msg_iter, m->msg_flags & MSG_DONTWAIT); +} + +static int macvtap_recvmsg(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, &m->msg_iter, flags & MSG_DONTWAIT); + if (ret > total_len) { + m->msg_flags |= MSG_TRUNC; + ret = flags & MSG_TRUNC ? ret : total_len; + } + return ret; +} + +static int macvtap_peek_len(struct socket *sock) +{ + struct macvtap_queue *q = container_of(sock, struct macvtap_queue, + sock); + return skb_array_peek_len(&q->skb_array); +} + +/* Ops structure to mimic raw sockets with tun */ +static const struct proto_ops macvtap_socket_ops = { + .sendmsg = macvtap_sendmsg, + .recvmsg = macvtap_recvmsg, + .peek_len = macvtap_peek_len, +}; + +/* 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); + +int macvtap_queue_resize(struct macvlan_dev *vlan) +{ + struct net_device *dev = vlan->dev; + struct macvtap_queue *q; + struct skb_array **arrays; + int n = vlan->numqueues; + int ret, i = 0; + + arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL); + if (!arrays) + return -ENOMEM; + + list_for_each_entry(q, &vlan->queue_list, next) + arrays[i++] = &q->skb_array; + + ret = skb_array_resize_multiple(arrays, n, + dev->tx_queue_len, GFP_KERNEL); + + kfree(arrays); + return ret; +} |