| // SPDX-License-Identifier: GPL-2.0-only |
| #include <linux/etherdevice.h> |
| #include <linux/if_tap.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/signal.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> |
| |
| #define TAP_IFFEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE) |
| |
| #define TAP_VNET_LE 0x80000000 |
| #define TAP_VNET_BE 0x40000000 |
| |
| #ifdef CONFIG_TUN_VNET_CROSS_LE |
| static inline bool tap_legacy_is_little_endian(struct tap_queue *q) |
| { |
| return q->flags & TAP_VNET_BE ? false : |
| virtio_legacy_is_little_endian(); |
| } |
| |
| static long tap_get_vnet_be(struct tap_queue *q, int __user *sp) |
| { |
| int s = !!(q->flags & TAP_VNET_BE); |
| |
| if (put_user(s, sp)) |
| return -EFAULT; |
| |
| return 0; |
| } |
| |
| static long tap_set_vnet_be(struct tap_queue *q, int __user *sp) |
| { |
| int s; |
| |
| if (get_user(s, sp)) |
| return -EFAULT; |
| |
| if (s) |
| q->flags |= TAP_VNET_BE; |
| else |
| q->flags &= ~TAP_VNET_BE; |
| |
| return 0; |
| } |
| #else |
| static inline bool tap_legacy_is_little_endian(struct tap_queue *q) |
| { |
| return virtio_legacy_is_little_endian(); |
| } |
| |
| static long tap_get_vnet_be(struct tap_queue *q, int __user *argp) |
| { |
| return -EINVAL; |
| } |
| |
| static long tap_set_vnet_be(struct tap_queue *q, int __user *argp) |
| { |
| return -EINVAL; |
| } |
| #endif /* CONFIG_TUN_VNET_CROSS_LE */ |
| |
| static inline bool tap_is_little_endian(struct tap_queue *q) |
| { |
| return q->flags & TAP_VNET_LE || |
| tap_legacy_is_little_endian(q); |
| } |
| |
| static inline u16 tap16_to_cpu(struct tap_queue *q, __virtio16 val) |
| { |
| return __virtio16_to_cpu(tap_is_little_endian(q), val); |
| } |
| |
| static inline __virtio16 cpu_to_tap16(struct tap_queue *q, u16 val) |
| { |
| return __cpu_to_virtio16(tap_is_little_endian(q), val); |
| } |
| |
| static struct proto tap_proto = { |
| .name = "tap", |
| .owner = THIS_MODULE, |
| .obj_size = sizeof(struct tap_queue), |
| }; |
| |
| #define TAP_NUM_DEVS (1U << MINORBITS) |
| |
| static LIST_HEAD(major_list); |
| |
| struct major_info { |
| struct rcu_head rcu; |
| dev_t major; |
| struct idr minor_idr; |
| spinlock_t minor_lock; |
| const char *device_name; |
| struct list_head next; |
| }; |
| |
| #define GOODCOPY_LEN 128 |
| |
| static const struct proto_ops tap_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 tap_dev *tap_dev_get_rcu(const struct net_device *dev) |
| { |
| return rcu_dereference(dev->rx_handler_data); |
| } |
| |
| /* |
| * RCU usage: |
| * The tap_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 tap_queue |
| * through sock_hold(&q->sk). When the macvlan_dev goes away first, |
| * q->vlan becomes inaccessible. When the files gets closed, |
| * tap_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 tap_enable_queue(struct tap_dev *tap, struct file *file, |
| struct tap_queue *q) |
| { |
| int err = -EINVAL; |
| |
| ASSERT_RTNL(); |
| |
| if (q->enabled) |
| goto out; |
| |
| err = 0; |
| rcu_assign_pointer(tap->taps[tap->numvtaps], q); |
| q->queue_index = tap->numvtaps; |
| q->enabled = true; |
| |
| tap->numvtaps++; |
| out: |
| return err; |
| } |
| |
| /* Requires RTNL */ |
| static int tap_set_queue(struct tap_dev *tap, struct file *file, |
| struct tap_queue *q) |
| { |
| if (tap->numqueues == MAX_TAP_QUEUES) |
| return -EBUSY; |
| |
| rcu_assign_pointer(q->tap, tap); |
| rcu_assign_pointer(tap->taps[tap->numvtaps], q); |
| sock_hold(&q->sk); |
| |
| q->file = file; |
| q->queue_index = tap->numvtaps; |
| q->enabled = true; |
| file->private_data = q; |
| list_add_tail(&q->next, &tap->queue_list); |
| |
| tap->numvtaps++; |
| tap->numqueues++; |
| |
| return 0; |
| } |
| |
| static int tap_disable_queue(struct tap_queue *q) |
| { |
| struct tap_dev *tap; |
| struct tap_queue *nq; |
| |
| ASSERT_RTNL(); |
| if (!q->enabled) |
| return -EINVAL; |
| |
| tap = rtnl_dereference(q->tap); |
| |
| if (tap) { |
| int index = q->queue_index; |
| BUG_ON(index >= tap->numvtaps); |
| nq = rtnl_dereference(tap->taps[tap->numvtaps - 1]); |
| nq->queue_index = index; |
| |
| rcu_assign_pointer(tap->taps[index], nq); |
| RCU_INIT_POINTER(tap->taps[tap->numvtaps - 1], NULL); |
| q->enabled = false; |
| |
| tap->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 tap_put_queue(struct tap_queue *q) |
| { |
| struct tap_dev *tap; |
| |
| rtnl_lock(); |
| tap = rtnl_dereference(q->tap); |
| |
| if (tap) { |
| if (q->enabled) |
| BUG_ON(tap_disable_queue(q)); |
| |
| tap->numqueues--; |
| RCU_INIT_POINTER(q->tap, 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 tap_queue *tap_get_queue(struct tap_dev *tap, |
| struct sk_buff *skb) |
| { |
| struct tap_queue *queue = 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 = READ_ONCE(tap->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) { |
| queue = rcu_dereference(tap->taps[rxq % numvtaps]); |
| goto out; |
| } |
| |
| if (likely(skb_rx_queue_recorded(skb))) { |
| rxq = skb_get_rx_queue(skb); |
| |
| while (unlikely(rxq >= numvtaps)) |
| rxq -= numvtaps; |
| |
| queue = rcu_dereference(tap->taps[rxq]); |
| goto out; |
| } |
| |
| single: |
| queue = rcu_dereference(tap->taps[0]); |
| out: |
| return queue; |
| } |
| |
| /* |
| * 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 tap_del_queues(struct tap_dev *tap) |
| { |
| struct tap_queue *q, *tmp; |
| |
| ASSERT_RTNL(); |
| list_for_each_entry_safe(q, tmp, &tap->queue_list, next) { |
| list_del_init(&q->next); |
| RCU_INIT_POINTER(q->tap, NULL); |
| if (q->enabled) |
| tap->numvtaps--; |
| tap->numqueues--; |
| sock_put(&q->sk); |
| } |
| BUG_ON(tap->numvtaps); |
| BUG_ON(tap->numqueues); |
| /* guarantee that any future tap_set_queue will fail */ |
| tap->numvtaps = MAX_TAP_QUEUES; |
| } |
| EXPORT_SYMBOL_GPL(tap_del_queues); |
| |
| rx_handler_result_t tap_handle_frame(struct sk_buff **pskb) |
| { |
| struct sk_buff *skb = *pskb; |
| struct net_device *dev = skb->dev; |
| struct tap_dev *tap; |
| struct tap_queue *q; |
| netdev_features_t features = TAP_FEATURES; |
| |
| tap = tap_dev_get_rcu(dev); |
| if (!tap) |
| return RX_HANDLER_PASS; |
| |
| q = tap_get_queue(tap, skb); |
| if (!q) |
| return RX_HANDLER_PASS; |
| |
| 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 |= tap->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 (ptr_ring_produce(&q->ring, skb)) |
| goto drop; |
| goto wake_up; |
| } |
| |
| consume_skb(skb); |
| while (segs) { |
| struct sk_buff *nskb = segs->next; |
| |
| segs->next = NULL; |
| if (ptr_ring_produce(&q->ring, 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 (ptr_ring_produce(&q->ring, skb)) |
| goto drop; |
| } |
| |
| wake_up: |
| wake_up_interruptible_poll(sk_sleep(&q->sk), EPOLLIN | EPOLLRDNORM | EPOLLRDBAND); |
| return RX_HANDLER_CONSUMED; |
| |
| drop: |
| /* Count errors/drops only here, thus don't care about args. */ |
| if (tap->count_rx_dropped) |
| tap->count_rx_dropped(tap); |
| kfree_skb(skb); |
| return RX_HANDLER_CONSUMED; |
| } |
| EXPORT_SYMBOL_GPL(tap_handle_frame); |
| |
| static struct major_info *tap_get_major(int major) |
| { |
| struct major_info *tap_major; |
| |
| list_for_each_entry_rcu(tap_major, &major_list, next) { |
| if (tap_major->major == major) |
| return tap_major; |
| } |
| |
| return NULL; |
| } |
| |
| int tap_get_minor(dev_t major, struct tap_dev *tap) |
| { |
| int retval = -ENOMEM; |
| struct major_info *tap_major; |
| |
| rcu_read_lock(); |
| tap_major = tap_get_major(MAJOR(major)); |
| if (!tap_major) { |
| retval = -EINVAL; |
| goto unlock; |
| } |
| |
| spin_lock(&tap_major->minor_lock); |
| retval = idr_alloc(&tap_major->minor_idr, tap, 1, TAP_NUM_DEVS, GFP_ATOMIC); |
| if (retval >= 0) { |
| tap->minor = retval; |
| } else if (retval == -ENOSPC) { |
| netdev_err(tap->dev, "Too many tap devices\n"); |
| retval = -EINVAL; |
| } |
| spin_unlock(&tap_major->minor_lock); |
| |
| unlock: |
| rcu_read_unlock(); |
| return retval < 0 ? retval : 0; |
| } |
| EXPORT_SYMBOL_GPL(tap_get_minor); |
| |
| void tap_free_minor(dev_t major, struct tap_dev *tap) |
| { |
| struct major_info *tap_major; |
| |
| rcu_read_lock(); |
| tap_major = tap_get_major(MAJOR(major)); |
| if (!tap_major) { |
| goto unlock; |
| } |
| |
| spin_lock(&tap_major->minor_lock); |
| if (tap->minor) { |
| idr_remove(&tap_major->minor_idr, tap->minor); |
| tap->minor = 0; |
| } |
| spin_unlock(&tap_major->minor_lock); |
| |
| unlock: |
| rcu_read_unlock(); |
| } |
| EXPORT_SYMBOL_GPL(tap_free_minor); |
| |
| static struct tap_dev *dev_get_by_tap_file(int major, int minor) |
| { |
| struct net_device *dev = NULL; |
| struct tap_dev *tap; |
| struct major_info *tap_major; |
| |
| rcu_read_lock(); |
| tap_major = tap_get_major(major); |
| if (!tap_major) { |
| tap = NULL; |
| goto unlock; |
| } |
| |
| spin_lock(&tap_major->minor_lock); |
| tap = idr_find(&tap_major->minor_idr, minor); |
| if (tap) { |
| dev = tap->dev; |
| dev_hold(dev); |
| } |
| spin_unlock(&tap_major->minor_lock); |
| |
| unlock: |
| rcu_read_unlock(); |
| return tap; |
| } |
| |
| static void tap_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, EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND); |
| } |
| |
| static void tap_sock_destruct(struct sock *sk) |
| { |
| struct tap_queue *q = container_of(sk, struct tap_queue, sk); |
| |
| ptr_ring_cleanup(&q->ring, __skb_array_destroy_skb); |
| } |
| |
| static int tap_open(struct inode *inode, struct file *file) |
| { |
| struct net *net = current->nsproxy->net_ns; |
| struct tap_dev *tap; |
| struct tap_queue *q; |
| int err = -ENODEV; |
| |
| rtnl_lock(); |
| tap = dev_get_by_tap_file(imajor(inode), iminor(inode)); |
| if (!tap) |
| goto err; |
| |
| err = -ENOMEM; |
| q = (struct tap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, |
| &tap_proto, 0); |
| if (!q) |
| goto err; |
| if (ptr_ring_init(&q->ring, tap->dev->tx_queue_len, GFP_KERNEL)) { |
| sk_free(&q->sk); |
| goto err; |
| } |
| |
| init_waitqueue_head(&q->sock.wq.wait); |
| q->sock.type = SOCK_RAW; |
| q->sock.state = SS_CONNECTED; |
| q->sock.file = file; |
| q->sock.ops = &tap_socket_ops; |
| sock_init_data(&q->sock, &q->sk); |
| q->sk.sk_write_space = tap_sock_write_space; |
| q->sk.sk_destruct = tap_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 tap, 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 ((tap->dev->features & NETIF_F_HIGHDMA) && (tap->dev->features & NETIF_F_SG)) |
| sock_set_flag(&q->sk, SOCK_ZEROCOPY); |
| |
| err = tap_set_queue(tap, file, q); |
| if (err) { |
| /* tap_sock_destruct() will take care of freeing ptr_ring */ |
| goto err_put; |
| } |
| |
| dev_put(tap->dev); |
| |
| rtnl_unlock(); |
| return err; |
| |
| err_put: |
| sock_put(&q->sk); |
| err: |
| if (tap) |
| dev_put(tap->dev); |
| |
| rtnl_unlock(); |
| return err; |
| } |
| |
| static int tap_release(struct inode *inode, struct file *file) |
| { |
| struct tap_queue *q = file->private_data; |
| tap_put_queue(q); |
| return 0; |
| } |
| |
| static __poll_t tap_poll(struct file *file, poll_table *wait) |
| { |
| struct tap_queue *q = file->private_data; |
| __poll_t mask = EPOLLERR; |
| |
| if (!q) |
| goto out; |
| |
| mask = 0; |
| poll_wait(file, &q->sock.wq.wait, wait); |
| |
| if (!ptr_ring_empty(&q->ring)) |
| mask |= EPOLLIN | EPOLLRDNORM; |
| |
| if (sock_writeable(&q->sk) || |
| (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &q->sock.flags) && |
| sock_writeable(&q->sk))) |
| mask |= EPOLLOUT | EPOLLWRNORM; |
| |
| out: |
| return mask; |
| } |
| |
| static inline struct sk_buff *tap_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 TAP_RESERVE HH_DATA_OFF(ETH_HLEN) |
| |
| /* Get packet from user space buffer */ |
| static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, |
| struct iov_iter *from, int noblock) |
| { |
| int good_linear = SKB_MAX_HEAD(TAP_RESERVE); |
| struct sk_buff *skb; |
| struct tap_dev *tap; |
| 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) && |
| tap16_to_cpu(q, vnet_hdr.csum_start) + |
| tap16_to_cpu(q, vnet_hdr.csum_offset) + 2 > |
| tap16_to_cpu(q, vnet_hdr.hdr_len)) |
| vnet_hdr.hdr_len = cpu_to_tap16(q, |
| tap16_to_cpu(q, vnet_hdr.csum_start) + |
| tap16_to_cpu(q, vnet_hdr.csum_offset) + 2); |
| err = -EINVAL; |
| if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len) |
| goto err; |
| } |
| |
| err = -EINVAL; |
| if (unlikely(len < ETH_HLEN)) |
| goto err; |
| |
| if (msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) { |
| struct iov_iter i; |
| |
| copylen = vnet_hdr.hdr_len ? |
| tap16_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 = tap16_to_cpu(q, vnet_hdr.hdr_len); |
| if (linear > good_linear) |
| linear = good_linear; |
| else if (linear < ETH_HLEN) |
| linear = ETH_HLEN; |
| } |
| |
| skb = tap_alloc_skb(&q->sk, TAP_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, |
| tap_is_little_endian(q)); |
| if (err) |
| goto err_kfree; |
| } |
| |
| skb_probe_transport_header(skb); |
| |
| /* 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(); |
| tap = rcu_dereference(q->tap); |
| /* copy skb_ubuf_info for callback when skb has no error */ |
| if (zerocopy) { |
| skb_shinfo(skb)->destructor_arg = msg_control; |
| skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; |
| skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; |
| } else if (msg_control) { |
| struct ubuf_info *uarg = msg_control; |
| uarg->callback(uarg, false); |
| } |
| |
| if (tap) { |
| skb->dev = tap->dev; |
| dev_queue_xmit(skb); |
| } else { |
| kfree_skb(skb); |
| } |
| rcu_read_unlock(); |
| |
| return total_len; |
| |
| err_kfree: |
| kfree_skb(skb); |
| |
| err: |
| rcu_read_lock(); |
| tap = rcu_dereference(q->tap); |
| if (tap && tap->count_tx_dropped) |
| tap->count_tx_dropped(tap); |
| rcu_read_unlock(); |
| |
| return err; |
| } |
| |
| static ssize_t tap_write_iter(struct kiocb *iocb, struct iov_iter *from) |
| { |
| struct file *file = iocb->ki_filp; |
| struct tap_queue *q = file->private_data; |
| |
| return tap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK); |
| } |
| |
| /* Put packet to the user space buffer */ |
| static ssize_t tap_put_user(struct tap_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) { |
| int vlan_hlen = skb_vlan_tag_present(skb) ? VLAN_HLEN : 0; |
| 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, |
| tap_is_little_endian(q), true, |
| vlan_hlen)) |
| 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 tap_do_read(struct tap_queue *q, |
| struct iov_iter *to, |
| int noblock, struct sk_buff *skb) |
| { |
| DEFINE_WAIT(wait); |
| ssize_t ret = 0; |
| |
| if (!iov_iter_count(to)) { |
| kfree_skb(skb); |
| return 0; |
| } |
| |
| if (skb) |
| goto put; |
| |
| while (1) { |
| if (!noblock) |
| prepare_to_wait(sk_sleep(&q->sk), &wait, |
| TASK_INTERRUPTIBLE); |
| |
| /* Read frames from the queue */ |
| skb = ptr_ring_consume(&q->ring); |
| 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); |
| |
| put: |
| if (skb) { |
| ret = tap_put_user(q, skb, to); |
| if (unlikely(ret < 0)) |
| kfree_skb(skb); |
| else |
| consume_skb(skb); |
| } |
| return ret; |
| } |
| |
| static ssize_t tap_read_iter(struct kiocb *iocb, struct iov_iter *to) |
| { |
| struct file *file = iocb->ki_filp; |
| struct tap_queue *q = file->private_data; |
| ssize_t len = iov_iter_count(to), ret; |
| |
| ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK, NULL); |
| ret = min_t(ssize_t, ret, len); |
| if (ret > 0) |
| iocb->ki_pos = ret; |
| return ret; |
| } |
| |
| static struct tap_dev *tap_get_tap_dev(struct tap_queue *q) |
| { |
| struct tap_dev *tap; |
| |
| ASSERT_RTNL(); |
| tap = rtnl_dereference(q->tap); |
| if (tap) |
| dev_hold(tap->dev); |
| |
| return tap; |
| } |
| |
| static void tap_put_tap_dev(struct tap_dev *tap) |
| { |
| dev_put(tap->dev); |
| } |
| |
| static int tap_ioctl_set_queue(struct file *file, unsigned int flags) |
| { |
| struct tap_queue *q = file->private_data; |
| struct tap_dev *tap; |
| int ret; |
| |
| tap = tap_get_tap_dev(q); |
| if (!tap) |
| return -EINVAL; |
| |
| if (flags & IFF_ATTACH_QUEUE) |
| ret = tap_enable_queue(tap, file, q); |
| else if (flags & IFF_DETACH_QUEUE) |
| ret = tap_disable_queue(q); |
| else |
| ret = -EINVAL; |
| |
| tap_put_tap_dev(tap); |
| return ret; |
| } |
| |
| static int set_offload(struct tap_queue *q, unsigned long arg) |
| { |
| struct tap_dev *tap; |
| netdev_features_t features; |
| netdev_features_t feature_mask = 0; |
| |
| tap = rtnl_dereference(q->tap); |
| if (!tap) |
| return -ENOLINK; |
| |
| features = tap->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; |
| } |
| } |
| |
| /* 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 tap, 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)) |
| features |= RX_OFFLOADS; |
| else |
| features &= ~RX_OFFLOADS; |
| |
| /* tap_features are the same as features on tun/tap and |
| * reflect user expectations. |
| */ |
| tap->tap_features = feature_mask; |
| if (tap->update_features) |
| tap->update_features(tap, features); |
| |
| return 0; |
| } |
| |
| /* |
| * provide compatibility with generic tun/tap interface |
| */ |
| static long tap_ioctl(struct file *file, unsigned int cmd, |
| unsigned long arg) |
| { |
| struct tap_queue *q = file->private_data; |
| struct tap_dev *tap; |
| 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 & ~TAP_IFFEATURES) != (IFF_NO_PI | IFF_TAP)) |
| ret = -EINVAL; |
| else |
| q->flags = (q->flags & ~TAP_IFFEATURES) | u; |
| |
| return ret; |
| |
| case TUNGETIFF: |
| rtnl_lock(); |
| tap = tap_get_tap_dev(q); |
| if (!tap) { |
| rtnl_unlock(); |
| return -ENOLINK; |
| } |
| |
| ret = 0; |
| u = q->flags; |
| if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) || |
| put_user(u, &ifr->ifr_flags)) |
| ret = -EFAULT; |
| tap_put_tap_dev(tap); |
| rtnl_unlock(); |
| return ret; |
| |
| case TUNSETQUEUE: |
| if (get_user(u, &ifr->ifr_flags)) |
| return -EFAULT; |
| rtnl_lock(); |
| ret = tap_ioctl_set_queue(file, u); |
| rtnl_unlock(); |
| return ret; |
| |
| case TUNGETFEATURES: |
| if (put_user(IFF_TAP | IFF_NO_PI | TAP_IFFEATURES, up)) |
| return -EFAULT; |
| return 0; |
| |
| case TUNSETSNDBUF: |
| if (get_user(s, sp)) |
| return -EFAULT; |
| if (s <= 0) |
| return -EINVAL; |
| |
| 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 & TAP_VNET_LE); |
| if (put_user(s, sp)) |
| return -EFAULT; |
| return 0; |
| |
| case TUNSETVNETLE: |
| if (get_user(s, sp)) |
| return -EFAULT; |
| if (s) |
| q->flags |= TAP_VNET_LE; |
| else |
| q->flags &= ~TAP_VNET_LE; |
| return 0; |
| |
| case TUNGETVNETBE: |
| return tap_get_vnet_be(q, sp); |
| |
| case TUNSETVNETBE: |
| return tap_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(); |
| tap = tap_get_tap_dev(q); |
| if (!tap) { |
| rtnl_unlock(); |
| return -ENOLINK; |
| } |
| ret = 0; |
| dev_get_mac_address(&sa, dev_net(tap->dev), tap->dev->name); |
| if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) || |
| copy_to_user(&ifr->ifr_hwaddr, &sa, sizeof(sa))) |
| ret = -EFAULT; |
| tap_put_tap_dev(tap); |
| rtnl_unlock(); |
| return ret; |
| |
| case SIOCSIFHWADDR: |
| if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa))) |
| return -EFAULT; |
| rtnl_lock(); |
| tap = tap_get_tap_dev(q); |
| if (!tap) { |
| rtnl_unlock(); |
| return -ENOLINK; |
| } |
| ret = dev_set_mac_address_user(tap->dev, &sa, NULL); |
| tap_put_tap_dev(tap); |
| rtnl_unlock(); |
| return ret; |
| |
| default: |
| return -EINVAL; |
| } |
| } |
| |
| #ifdef CONFIG_COMPAT |
| static long tap_compat_ioctl(struct file *file, unsigned int cmd, |
| unsigned long arg) |
| { |
| return tap_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); |
| } |
| #endif |
| |
| static const struct file_operations tap_fops = { |
| .owner = THIS_MODULE, |
| .open = tap_open, |
| .release = tap_release, |
| .read_iter = tap_read_iter, |
| .write_iter = tap_write_iter, |
| .poll = tap_poll, |
| .llseek = no_llseek, |
| .unlocked_ioctl = tap_ioctl, |
| #ifdef CONFIG_COMPAT |
| .compat_ioctl = tap_compat_ioctl, |
| #endif |
| }; |
| |
| static int tap_get_user_xdp(struct tap_queue *q, struct xdp_buff *xdp) |
| { |
| struct tun_xdp_hdr *hdr = xdp->data_hard_start; |
| struct virtio_net_hdr *gso = &hdr->gso; |
| int buflen = hdr->buflen; |
| int vnet_hdr_len = 0; |
| struct tap_dev *tap; |
| struct sk_buff *skb; |
| int err, depth; |
| |
| if (q->flags & IFF_VNET_HDR) |
| vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz); |
| |
| skb = build_skb(xdp->data_hard_start, buflen); |
| if (!skb) { |
| err = -ENOMEM; |
| goto err; |
| } |
| |
| skb_reserve(skb, xdp->data - xdp->data_hard_start); |
| skb_put(skb, xdp->data_end - xdp->data); |
| |
| 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, gso, tap_is_little_endian(q)); |
| if (err) |
| goto err_kfree; |
| } |
| |
| /* 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(); |
| tap = rcu_dereference(q->tap); |
| if (tap) { |
| skb->dev = tap->dev; |
| skb_probe_transport_header(skb); |
| dev_queue_xmit(skb); |
| } else { |
| kfree_skb(skb); |
| } |
| rcu_read_unlock(); |
| |
| return 0; |
| |
| err_kfree: |
| kfree_skb(skb); |
| err: |
| rcu_read_lock(); |
| tap = rcu_dereference(q->tap); |
| if (tap && tap->count_tx_dropped) |
| tap->count_tx_dropped(tap); |
| rcu_read_unlock(); |
| return err; |
| } |
| |
| static int tap_sendmsg(struct socket *sock, struct msghdr *m, |
| size_t total_len) |
| { |
| struct tap_queue *q = container_of(sock, struct tap_queue, sock); |
| struct tun_msg_ctl *ctl = m->msg_control; |
| struct xdp_buff *xdp; |
| int i; |
| |
| if (ctl && (ctl->type == TUN_MSG_PTR)) { |
| for (i = 0; i < ctl->num; i++) { |
| xdp = &((struct xdp_buff *)ctl->ptr)[i]; |
| tap_get_user_xdp(q, xdp); |
| } |
| return 0; |
| } |
| |
| return tap_get_user(q, ctl ? ctl->ptr : NULL, &m->msg_iter, |
| m->msg_flags & MSG_DONTWAIT); |
| } |
| |
| static int tap_recvmsg(struct socket *sock, struct msghdr *m, |
| size_t total_len, int flags) |
| { |
| struct tap_queue *q = container_of(sock, struct tap_queue, sock); |
| struct sk_buff *skb = m->msg_control; |
| int ret; |
| if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) { |
| kfree_skb(skb); |
| return -EINVAL; |
| } |
| ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT, skb); |
| if (ret > total_len) { |
| m->msg_flags |= MSG_TRUNC; |
| ret = flags & MSG_TRUNC ? ret : total_len; |
| } |
| return ret; |
| } |
| |
| static int tap_peek_len(struct socket *sock) |
| { |
| struct tap_queue *q = container_of(sock, struct tap_queue, |
| sock); |
| return PTR_RING_PEEK_CALL(&q->ring, __skb_array_len_with_tag); |
| } |
| |
| /* Ops structure to mimic raw sockets with tun */ |
| static const struct proto_ops tap_socket_ops = { |
| .sendmsg = tap_sendmsg, |
| .recvmsg = tap_recvmsg, |
| .peek_len = tap_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 *tap_get_socket(struct file *file) |
| { |
| struct tap_queue *q; |
| if (file->f_op != &tap_fops) |
| return ERR_PTR(-EINVAL); |
| q = file->private_data; |
| if (!q) |
| return ERR_PTR(-EBADFD); |
| return &q->sock; |
| } |
| EXPORT_SYMBOL_GPL(tap_get_socket); |
| |
| struct ptr_ring *tap_get_ptr_ring(struct file *file) |
| { |
| struct tap_queue *q; |
| |
| if (file->f_op != &tap_fops) |
| return ERR_PTR(-EINVAL); |
| q = file->private_data; |
| if (!q) |
| return ERR_PTR(-EBADFD); |
| return &q->ring; |
| } |
| EXPORT_SYMBOL_GPL(tap_get_ptr_ring); |
| |
| int tap_queue_resize(struct tap_dev *tap) |
| { |
| struct net_device *dev = tap->dev; |
| struct tap_queue *q; |
| struct ptr_ring **rings; |
| int n = tap->numqueues; |
| int ret, i = 0; |
| |
| rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL); |
| if (!rings) |
| return -ENOMEM; |
| |
| list_for_each_entry(q, &tap->queue_list, next) |
| rings[i++] = &q->ring; |
| |
| ret = ptr_ring_resize_multiple(rings, n, |
| dev->tx_queue_len, GFP_KERNEL, |
| __skb_array_destroy_skb); |
| |
| kfree(rings); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(tap_queue_resize); |
| |
| static int tap_list_add(dev_t major, const char *device_name) |
| { |
| struct major_info *tap_major; |
| |
| tap_major = kzalloc(sizeof(*tap_major), GFP_ATOMIC); |
| if (!tap_major) |
| return -ENOMEM; |
| |
| tap_major->major = MAJOR(major); |
| |
| idr_init(&tap_major->minor_idr); |
| spin_lock_init(&tap_major->minor_lock); |
| |
| tap_major->device_name = device_name; |
| |
| list_add_tail_rcu(&tap_major->next, &major_list); |
| return 0; |
| } |
| |
| int tap_create_cdev(struct cdev *tap_cdev, dev_t *tap_major, |
| const char *device_name, struct module *module) |
| { |
| int err; |
| |
| err = alloc_chrdev_region(tap_major, 0, TAP_NUM_DEVS, device_name); |
| if (err) |
| goto out1; |
| |
| cdev_init(tap_cdev, &tap_fops); |
| tap_cdev->owner = module; |
| err = cdev_add(tap_cdev, *tap_major, TAP_NUM_DEVS); |
| if (err) |
| goto out2; |
| |
| err = tap_list_add(*tap_major, device_name); |
| if (err) |
| goto out3; |
| |
| return 0; |
| |
| out3: |
| cdev_del(tap_cdev); |
| out2: |
| unregister_chrdev_region(*tap_major, TAP_NUM_DEVS); |
| out1: |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(tap_create_cdev); |
| |
| void tap_destroy_cdev(dev_t major, struct cdev *tap_cdev) |
| { |
| struct major_info *tap_major, *tmp; |
| |
| cdev_del(tap_cdev); |
| unregister_chrdev_region(major, TAP_NUM_DEVS); |
| list_for_each_entry_safe(tap_major, tmp, &major_list, next) { |
| if (tap_major->major == MAJOR(major)) { |
| idr_destroy(&tap_major->minor_idr); |
| list_del_rcu(&tap_major->next); |
| kfree_rcu(tap_major, rcu); |
| } |
| } |
| } |
| EXPORT_SYMBOL_GPL(tap_destroy_cdev); |
| |
| MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); |
| MODULE_AUTHOR("Sainath Grandhi <sainath.grandhi@intel.com>"); |
| MODULE_LICENSE("GPL"); |