v4.19.13 snapshot.
diff --git a/include/linux/if_tap.h b/include/linux/if_tap.h
new file mode 100644
index 0000000..8e66866
--- /dev/null
+++ b/include/linux/if_tap.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_IF_TAP_H_
+#define _LINUX_IF_TAP_H_
+
+#if IS_ENABLED(CONFIG_TAP)
+struct socket *tap_get_socket(struct file *);
+struct ptr_ring *tap_get_ptr_ring(struct file *file);
+#else
+#include <linux/err.h>
+#include <linux/errno.h>
+struct file;
+struct socket;
+static inline struct socket *tap_get_socket(struct file *f)
+{
+ return ERR_PTR(-EINVAL);
+}
+static inline struct ptr_ring *tap_get_ptr_ring(struct file *f)
+{
+ return ERR_PTR(-EINVAL);
+}
+#endif /* CONFIG_TAP */
+
+#include <net/sock.h>
+#include <linux/skb_array.h>
+
+/*
+ * Maximum times a tap device can be opened. This can be used to
+ * configure the number of receive queue, e.g. for multiqueue virtio.
+ */
+#define MAX_TAP_QUEUES 256
+
+struct tap_queue;
+
+struct tap_dev {
+ struct net_device *dev;
+ u16 flags;
+ /* This array tracks active taps. */
+ struct tap_queue __rcu *taps[MAX_TAP_QUEUES];
+ /* This list tracks all taps (both enabled and disabled) */
+ struct list_head queue_list;
+ int numvtaps;
+ int numqueues;
+ netdev_features_t tap_features;
+ int minor;
+
+ void (*update_features)(struct tap_dev *tap, netdev_features_t features);
+ void (*count_tx_dropped)(struct tap_dev *tap);
+ void (*count_rx_dropped)(struct tap_dev *tap);
+};
+
+/*
+ * A tap queue is the central object of tap module, it connects
+ * an open character device to virtual interface. There can be
+ * multiple queues on one interface, which map back to queues
+ * implemented in hardware on the underlying device.
+ *
+ * tap_proto is used to allocate queues through the sock allocation
+ * mechanism.
+ *
+ */
+
+struct tap_queue {
+ struct sock sk;
+ struct socket sock;
+ struct socket_wq wq;
+ int vnet_hdr_sz;
+ struct tap_dev __rcu *tap;
+ struct file *file;
+ unsigned int flags;
+ u16 queue_index;
+ bool enabled;
+ struct list_head next;
+ struct ptr_ring ring;
+};
+
+rx_handler_result_t tap_handle_frame(struct sk_buff **pskb);
+void tap_del_queues(struct tap_dev *tap);
+int tap_get_minor(dev_t major, struct tap_dev *tap);
+void tap_free_minor(dev_t major, struct tap_dev *tap);
+int tap_queue_resize(struct tap_dev *tap);
+int tap_create_cdev(struct cdev *tap_cdev, dev_t *tap_major,
+ const char *device_name, struct module *module);
+void tap_destroy_cdev(dev_t major, struct cdev *tap_cdev);
+
+#endif /*_LINUX_IF_TAP_H_*/