#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/ipv6.h> #include <net/net_namespace.h> #include <net/rtnetlink.h> #include <net/sock.h> #include <linux/virtio_net.h> /* * A macvtap queue is the central object of this driver, it connects * an open character device to a macvlan interface. There can be * multiple queues on one interface, which map back to queues * implemented in hardware on the underlying device. * * macvtap_proto is used to allocate queues through the sock allocation * mechanism. * */ 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; }; #define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_VNET_LE | IFF_MULTI_QUEUE) static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) { return __virtio16_to_cpu(q->flags & IFF_VNET_LE, val); } static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val) { return __cpu_to_virtio16(q->flags & IFF_VNET_LE, val); } static struct proto macvtap_proto = { .name = "macvtap", .owner = THIS_MODULE, .obj_size = sizeof (struct macvtap_queue), }; /* * Variables for dealing with macvtaps device numbers. */ static dev_t macvtap_major; #define MACVTAP_NUM_DEVS (1U << MINORBITS) static DEFINE_MUTEX(minor_lock); static DEFINE_IDR(minor_idr); #define GOODCOPY_LEN 128 static struct class *macvtap_class; static struct cdev macvtap_cdev; static const struct proto_ops macvtap_socket_ops; #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \ NETIF_F_TSO6) #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO) #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG) 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; /* 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; } 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. */ static void macvtap_del_queues(struct net_device *dev) { struct macvlan_dev *vlan = netdev_priv(dev); struct macvtap_queue *q, *tmp, *qlist[MAX_MACVTAP_QUEUES]; int i, j = 0; ASSERT_RTNL(); list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) { list_del_init(&q->next); qlist[j++] = q; RCU_INIT_POINTER(q->vlan, NULL); if (q->enabled) vlan->numvtaps--; vlan->numqueues--; } for (i = 0; i < vlan->numvtaps; i++) RCU_INIT_POINTER(vlan->taps[i], NULL); BUG_ON(vlan->numvtaps); BUG_ON(vlan->numqueues); /* guarantee that any future macvtap_set_queue will fail */ vlan->numvtaps = MAX_MACVTAP_QUEUES; for (--j; j >= 0; j--) sock_put(&qlist[j]->sk); } static 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_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len) 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(dev, skb, features)) { struct sk_buff *segs = __skb_gso_segment(skb, features, false); if (IS_ERR(segs)) goto drop; if (!segs) { skb_queue_tail(&q->sk.sk_receive_queue, skb); goto wake_up; } kfree_skb(skb); while (segs) { struct sk_buff *nskb = segs->next; segs->next = NULL; skb_queue_tail(&q->sk.sk_receive_queue, segs); 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_ALL_CSUM) && skb_checksum_help(skb)) goto drop; skb_queue_tail(&q->sk.sk_receive_queue, skb); } 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; } static 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) { printk(KERN_ERR "too many macvtap devices\n"); retval = -EINVAL; } mutex_unlock(&minor_lock); return retval < 0 ? retval : 0; } static 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 int macvtap_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[], struct nlattr *data[]) { struct macvlan_dev *vlan = netdev_priv(dev); int err; INIT_LIST_HEAD(&vlan->queue_list); /* Since macvlan supports all offloads by default, make * tap support all offloads also. */ vlan->tap_features = TUN_OFFLOADS; err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan); if (err) return err; /* Don't put anything that may fail after macvlan_common_newlink * because we can't undo what it does. */ return macvlan_common_newlink(src_net, dev, tb, data); } static void macvtap_dellink(struct net_device *dev, struct list_head *head) { netdev_rx_handler_unregister(dev); macvtap_del_queues(dev); macvlan_dellink(dev, head); } static void macvtap_setup(struct net_device *dev) { macvlan_common_setup(dev); dev->tx_queue_len = TUN_READQ_SIZE; } static struct rtnl_link_ops macvtap_link_ops __read_mostly = { .kind = "macvtap", .setup = macvtap_setup, .newlink = macvtap_newlink, .dellink = macvtap_dellink, }; static void macvtap_sock_write_space(struct sock *sk) { wait_queue_head_t *wqueue; if (!sock_writeable(sk) || !test_and_clear_bit(SOCK_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) { skb_queue_purge(&sk->sk_receive_queue); } 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 out; err = -ENOMEM; q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &macvtap_proto); if (!q) goto out; 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 = macvtap_set_queue(dev, file, q); if (err) sock_put(&q->sk); out: 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_queue_empty(&q->sk.sk_receive_queue)) mask |= POLLIN | POLLRDNORM; if (sock_writeable(&q->sk) || (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) && sock_writeable(&q->sk))) mask |= POLLOUT | POLLWRNORM; out: return mask; } static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad, size_t len, size_t linear, int noblock, int *err) { struct sk_buff *skb; /* Under a page? Don't bother with paged skb. */ if (prepad + len < PAGE_SIZE || !linear) linear = len; skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, err, 0); if (!skb) return NULL; skb_reserve(skb, prepad); skb_put(skb, linear); skb->data_len = len - linear; skb->len += len - linear; return skb; } /* * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should * be shared with the tun/tap driver. */ static int macvtap_skb_from_vnet_hdr(struct macvtap_queue *q, struct sk_buff *skb, struct virtio_net_hdr *vnet_hdr) { unsigned short gso_type = 0; if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { case VIRTIO_NET_HDR_GSO_TCPV4: gso_type = SKB_GSO_TCPV4; break; case VIRTIO_NET_HDR_GSO_TCPV6: gso_type = SKB_GSO_TCPV6; break; case VIRTIO_NET_HDR_GSO_UDP: pr_warn_once("macvtap: %s: using disabled UFO feature; please fix this program\n", current->comm); gso_type = SKB_GSO_UDP; if (skb->protocol == htons(ETH_P_IPV6)) ipv6_proxy_select_ident(skb); break; default: return -EINVAL; } if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) gso_type |= SKB_GSO_TCP_ECN; if (vnet_hdr->gso_size == 0) return -EINVAL; } if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { if (!skb_partial_csum_set(skb, macvtap16_to_cpu(q, vnet_hdr->csum_start), macvtap16_to_cpu(q, vnet_hdr->csum_offset))) return -EINVAL; } if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { skb_shinfo(skb)->gso_size = macvtap16_to_cpu(q, vnet_hdr->gso_size); skb_shinfo(skb)->gso_type = gso_type; /* Header must be checked, and gso_segs computed. */ skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; skb_shinfo(skb)->gso_segs = 0; } return 0; } static void macvtap_skb_to_vnet_hdr(struct macvtap_queue *q, const struct sk_buff *skb, struct virtio_net_hdr *vnet_hdr) { memset(vnet_hdr, 0, sizeof(*vnet_hdr)); if (skb_is_gso(skb)) { struct skb_shared_info *sinfo = skb_shinfo(skb); /* This is a hint as to how much should be linear. */ vnet_hdr->hdr_len = cpu_to_macvtap16(q, skb_headlen(skb)); vnet_hdr->gso_size = cpu_to_macvtap16(q, sinfo->gso_size); if (sinfo->gso_type & SKB_GSO_TCPV4) vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; else if (sinfo->gso_type & SKB_GSO_TCPV6) vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; else BUG(); if (sinfo->gso_type & SKB_GSO_TCP_ECN) vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; } else vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; if (skb->ip_summed == CHECKSUM_PARTIAL) { vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; if (vlan_tx_tag_present(skb)) vnet_hdr->csum_start = cpu_to_macvtap16(q, skb_checksum_start_offset(skb) + VLAN_HLEN); else vnet_hdr->csum_start = cpu_to_macvtap16(q, skb_checksum_start_offset(skb)); vnet_hdr->csum_offset = cpu_to_macvtap16(q, skb->csum_offset); } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; } /* else everything is zero */ } /* 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(NET_IP_ALIGN); 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; bool zerocopy = false; size_t linear; ssize_t n; if (q->flags & IFF_VNET_HDR) { vnet_hdr_len = q->vnet_hdr_sz; err = -EINVAL; if (len < vnet_hdr_len) goto err; len -= vnet_hdr_len; err = -EFAULT; n = copy_from_iter(&vnet_hdr, sizeof(vnet_hdr), from); if (n != sizeof(vnet_hdr)) 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; 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; if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > good_linear) linear = good_linear; else linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len); } skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, 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 && m && m->msg_control) { struct ubuf_info *uarg = m->msg_control; uarg->callback(uarg, false); } } if (err) goto err_kfree; skb_set_network_header(skb, ETH_HLEN); skb_reset_mac_header(skb); skb->protocol = eth_hdr(skb)->h_proto; if (vnet_hdr_len) { err = macvtap_skb_from_vnet_hdr(q, skb, &vnet_hdr); if (err) goto err_kfree; } skb_probe_transport_header(skb, ETH_HLEN); 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; } 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 = q->vnet_hdr_sz; if (iov_iter_count(iter) < vnet_hdr_len) return -EINVAL; macvtap_skb_to_vnet_hdr(q, skb, &vnet_hdr); 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 (vlan_tx_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(vlan_tx_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_dequeue(&q->sk.sk_receive_queue); if (skb) break; if (noblock) { ret = -EAGAIN; break; } if (signal_pending(current)) { ret = -ERESTARTSYS; break; } /* Nothing to read, let's sleep */ schedule(); } if (skb) { ret = macvtap_put_user(q, skb, to); if (unlikely(ret < 0)) kfree_skb(skb); else consume_skb(skb); } if (!noblock) finish_wait(sk_sleep(&q->sk), &wait); 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; } } /* 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)) 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 int u; int __user *sp = argp; 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 = u; return ret; case TUNGETIFF: rtnl_lock(); vlan = macvtap_get_vlan(q); if (!vlan) { rtnl_unlock(); return -ENOLINK; } ret = 0; if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || put_user(q->flags, &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(u, up)) return -EFAULT; q->sk.sk_sndbuf = u; 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 TUNSETOFFLOAD: /* let the user check for future flags */ if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | TUN_F_TSO_ECN)) return -EINVAL; rtnl_lock(); ret = set_offload(q, arg); 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 static const struct file_operations macvtap_fops = { .owner = THIS_MODULE, .open = macvtap_open, .release = macvtap_release, .read = new_sync_read, .write = new_sync_write, .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 kiocb *iocb, struct socket *sock, struct msghdr *m, size_t total_len) { struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT); } static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m, size_t total_len, int flags) { struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); int ret; if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) return -EINVAL; ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT); if (ret > total_len) { m->msg_flags |= MSG_TRUNC; ret = flags & MSG_TRUNC ? ret : total_len; } return ret; } /* Ops structure to mimic raw sockets with tun */ static const struct proto_ops macvtap_socket_ops = { .sendmsg = macvtap_sendmsg, .recvmsg = macvtap_recvmsg, }; /* Get an underlying socket object from tun file. Returns error unless file is * attached to a device. The returned object works like a packet socket, it * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for * holding a reference to the file for as long as the socket is in use. */ struct socket *macvtap_get_socket(struct file *file) { struct macvtap_queue *q; if (file->f_op != &macvtap_fops) return ERR_PTR(-EINVAL); q = file->private_data; if (!q) return ERR_PTR(-EBADFD); return &q->sock; } EXPORT_SYMBOL_GPL(macvtap_get_socket); static int macvtap_device_event(struct notifier_block *unused, unsigned long event, void *ptr) { struct net_device *dev = netdev_notifier_info_to_dev(ptr); struct macvlan_dev *vlan; struct device *classdev; dev_t devt; int err; if (dev->rtnl_link_ops != &macvtap_link_ops) return NOTIFY_DONE; vlan = netdev_priv(dev); switch (event) { case NETDEV_REGISTER: /* Create the device node here after the network device has * been registered but before register_netdevice has * finished running. */ err = macvtap_get_minor(vlan); if (err) return notifier_from_errno(err); devt = MKDEV(MAJOR(macvtap_major), vlan->minor); classdev = device_create(macvtap_class, &dev->dev, devt, dev, "tap%d", dev->ifindex); if (IS_ERR(classdev)) { macvtap_free_minor(vlan); return notifier_from_errno(PTR_ERR(classdev)); } break; case NETDEV_UNREGISTER: devt = MKDEV(MAJOR(macvtap_major), vlan->minor); device_destroy(macvtap_class, devt); macvtap_free_minor(vlan); break; } return NOTIFY_DONE; } static struct notifier_block macvtap_notifier_block __read_mostly = { .notifier_call = macvtap_device_event, }; static int macvtap_init(void) { int err; err = alloc_chrdev_region(&macvtap_major, 0, MACVTAP_NUM_DEVS, "macvtap"); if (err) goto out1; cdev_init(&macvtap_cdev, &macvtap_fops); err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS); if (err) goto out2; macvtap_class = class_create(THIS_MODULE, "macvtap"); if (IS_ERR(macvtap_class)) { err = PTR_ERR(macvtap_class); goto out3; } err = register_netdevice_notifier(&macvtap_notifier_block); if (err) goto out4; err = macvlan_link_register(&macvtap_link_ops); if (err) goto out5; return 0; out5: unregister_netdevice_notifier(&macvtap_notifier_block); out4: class_unregister(macvtap_class); out3: cdev_del(&macvtap_cdev); out2: unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); out1: return err; } module_init(macvtap_init); static void macvtap_exit(void) { rtnl_link_unregister(&macvtap_link_ops); unregister_netdevice_notifier(&macvtap_notifier_block); class_unregister(macvtap_class); cdev_del(&macvtap_cdev); unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); } module_exit(macvtap_exit); MODULE_ALIAS_RTNL_LINK("macvtap"); MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); MODULE_LICENSE("GPL");