--- /dev/null
+#include <linux/etherdevice.h>
+#include <linux/if_macvlan.h>
+#include <linux/if_vlan.h>
+#include <linux/interrupt.h>
+#include <linux/nsproxy.h>
+#include <linux/compat.h>
+#include <linux/if_tun.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/cache.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/cdev.h>
+#include <linux/idr.h>
+#include <linux/fs.h>
+#include <linux/uio.h>
+
+#include <net/net_namespace.h>
+#include <net/rtnetlink.h>
+#include <net/sock.h>
+#include <linux/virtio_net.h>
+
+/*
+ * 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_MULTI_QUEUE)
+
+#define MACVTAP_VNET_LE 0x80000000
+
+static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val)
+{
+ return __virtio16_to_cpu(q->flags & MACVTAP_VNET_LE, val);
+}
+
+static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val)
+{
+ return __cpu_to_virtio16(q->flags & MACVTAP_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 | NETIF_F_UFO)
+#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(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:
+ gso_type = SKB_GSO_UDP;
+ 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 if (sinfo->gso_type & SKB_GSO_UDP)
+ vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
+ 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 (skb_vlan_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 */
+}
+
+/* Neighbour code has some assumptions on HH_DATA_MOD alignment */
+#define MACVTAP_RESERVE HH_DATA_OFF(ETH_HLEN)
+
+/* Get packet from user space buffer */
+static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
+ struct iov_iter *from, int noblock)
+{
+ int good_linear = SKB_MAX_HEAD(MACVTAP_RESERVE);
+ struct sk_buff *skb;
+ struct macvlan_dev *vlan;
+ unsigned long total_len = iov_iter_count(from);
+ unsigned long len = total_len;
+ int err;
+ struct virtio_net_hdr vnet_hdr = { 0 };
+ int vnet_hdr_len = 0;
+ int copylen = 0;
+ 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, MACVTAP_RESERVE, copylen,
+ linear, noblock, &err);
+ if (!skb)
+ goto err;
+
+ if (zerocopy)
+ err = zerocopy_sg_from_iter(skb, from);
+ else {
+ err = skb_copy_datagram_from_iter(skb, 0, from, len);
+ if (!err && 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 (skb_vlan_tag_present(skb)) {
+ struct {
+ __be16 h_vlan_proto;
+ __be16 h_vlan_TCI;
+ } veth;
+ veth.h_vlan_proto = skb->vlan_proto;
+ veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
+
+ vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
+ total += VLAN_HLEN;
+
+ ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
+ if (ret || !iov_iter_count(iter))
+ goto done;
+
+ ret = copy_to_iter(&veth, sizeof(veth), iter);
+ if (ret != sizeof(veth) || !iov_iter_count(iter))
+ goto done;
+ }
+
+ ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
+ skb->len - vlan_offset);
+
+done:
+ return ret ? ret : total;
+}
+
+static ssize_t macvtap_do_read(struct macvtap_queue *q,
+ struct iov_iter *to,
+ int noblock)
+{
+ DEFINE_WAIT(wait);
+ struct sk_buff *skb;
+ ssize_t ret = 0;
+
+ if (!iov_iter_count(to))
+ return 0;
+
+ while (1) {
+ if (!noblock)
+ prepare_to_wait(sk_sleep(&q->sk), &wait,
+ TASK_INTERRUPTIBLE);
+
+ /* Read frames from the queue */
+ skb = skb_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;
+ }
+
+ if (arg & TUN_F_UFO)
+ feature_mask |= NETIF_F_UFO;
+ }
+
+ /* tun/tap driver inverts the usage for TSO offloads, where
+ * setting the TSO bit means that the userspace wants to
+ * accept TSO frames and turning it off means that user space
+ * does not support TSO.
+ * For macvtap, we have to invert it to mean the same thing.
+ * When user space turns off TSO, we turn off GSO/LRO so that
+ * user-space will not receive TSO frames.
+ */
+ if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
+ features |= RX_OFFLOADS;
+ else
+ features &= ~RX_OFFLOADS;
+
+ /* tap_features are the same as features on tun/tap and
+ * reflect user expectations.
+ */
+ vlan->tap_features = feature_mask;
+ vlan->set_features = features;
+ netdev_update_features(vlan->dev);
+
+ return 0;
+}
+
+/*
+ * provide compatibility with generic tun/tap interface
+ */
+static long macvtap_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct macvtap_queue *q = file->private_data;
+ struct macvlan_dev *vlan;
+ void __user *argp = (void __user *)arg;
+ struct ifreq __user *ifr = argp;
+ unsigned int __user *up = argp;
+ unsigned short u;
+ int __user *sp = argp;
+ int s;
+ int ret;
+
+ switch (cmd) {
+ case TUNSETIFF:
+ /* ignore the name, just look at flags */
+ if (get_user(u, &ifr->ifr_flags))
+ return -EFAULT;
+
+ ret = 0;
+ if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP))
+ ret = -EINVAL;
+ else
+ q->flags = (q->flags & ~MACVTAP_FEATURES) | u;
+
+ return ret;
+
+ case TUNGETIFF:
+ rtnl_lock();
+ vlan = macvtap_get_vlan(q);
+ if (!vlan) {
+ rtnl_unlock();
+ return -ENOLINK;
+ }
+
+ ret = 0;
+ u = q->flags;
+ if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
+ put_user(u, &ifr->ifr_flags))
+ ret = -EFAULT;
+ macvtap_put_vlan(vlan);
+ rtnl_unlock();
+ return ret;
+
+ case TUNSETQUEUE:
+ if (get_user(u, &ifr->ifr_flags))
+ return -EFAULT;
+ rtnl_lock();
+ ret = macvtap_ioctl_set_queue(file, u);
+ rtnl_unlock();
+ return ret;
+
+ case TUNGETFEATURES:
+ if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up))
+ return -EFAULT;
+ return 0;
+
+ case TUNSETSNDBUF:
+ if (get_user(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 TUNGETVNETLE:
+ s = !!(q->flags & MACVTAP_VNET_LE);
+ if (put_user(s, sp))
+ return -EFAULT;
+ return 0;
+
+ case TUNSETVNETLE:
+ if (get_user(s, sp))
+ return -EFAULT;
+ if (s)
+ q->flags |= MACVTAP_VNET_LE;
+ else
+ q->flags &= ~MACVTAP_VNET_LE;
+ return 0;
+
+ case 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;
+
+ 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_iter = macvtap_read_iter,
+ .write_iter = macvtap_write_iter,
+ .poll = macvtap_poll,
+ .llseek = no_llseek,
+ .unlocked_ioctl = macvtap_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = macvtap_compat_ioctl,
+#endif
+};
+
+static int macvtap_sendmsg(struct socket *sock, struct msghdr *m,
+ size_t total_len)
+{
+ struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
+ return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT);
+}
+
+static int macvtap_recvmsg(struct socket *sock, struct msghdr *m,
+ size_t total_len, int flags)
+{
+ struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
+ int ret;
+ if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
+ return -EINVAL;
+ ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);
+ if (ret > total_len) {
+ m->msg_flags |= MSG_TRUNC;
+ ret = flags & MSG_TRUNC ? ret : total_len;
+ }
+ return ret;
+}
+
+/* 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");
Code Review / kvmfornfv.git / blobdiff