#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; } 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 = &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->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; u = tap->dev->type; if (copy_to_user(&ifr->ifr_name, tap->dev->name, IFNAMSIZ) || copy_to_user(&ifr->ifr_hwaddr.sa_data, tap->dev->dev_addr, ETH_ALEN) || put_user(u, &ifr->ifr_hwaddr.sa_family)) 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(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");