v4.19.13 snapshot.
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
new file mode 100644
index 0000000..f0f7cd9
--- /dev/null
+++ b/drivers/net/tap.c
@@ -0,0 +1,1309 @@
+#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, struct msghdr *m,
+ 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 (m && m->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, ETH_HLEN);
+
+ /* Move network header to the right position for VLAN tagged packets */
+ if ((skb->protocol == htons(ETH_P_8021Q) ||
+ skb->protocol == htons(ETH_P_8021AD)) &&
+ __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
+ skb_set_network_header(skb, depth);
+
+ rcu_read_lock();
+ tap = rcu_dereference(q->tap);
+ /* copy skb_ubuf_info for callback when skb has no error */
+ if (zerocopy) {
+ skb_shinfo(skb)->destructor_arg = m->msg_control;
+ skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
+ skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
+ } else if (m && m->msg_control) {
+ struct ubuf_info *uarg = m->msg_control;
+ uarg->callback(uarg, false);
+ }
+
+ if (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)) {
+ if (skb)
+ 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);
+ 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_sendmsg(struct socket *sock, struct msghdr *m,
+ size_t total_len)
+{
+ struct tap_queue *q = container_of(sock, struct tap_queue, sock);
+ return tap_get_user(q, m, &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)) {
+ if (skb)
+ 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");