text: /*
   * Kernel/userspace transport abstraction for Hyper-V util driver.
   *
   * Copyright (C) 2015, Vitaly Kuznetsov <vkuznets@redhat.com>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published
   * by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
   * NON INFRINGEMENT.  See the GNU General Public License for more
   * details.
   *
   */
  
  #ifndef _HV_UTILS_TRANSPORT_H
  #define _HV_UTILS_TRANSPORT_H
  
  #include <linux/connector.h>
  #include <linux/miscdevice.h>
  
  enum hvutil_transport_mode {
  	HVUTIL_TRANSPORT_INIT = 0,
  	HVUTIL_TRANSPORT_NETLINK,
  	HVUTIL_TRANSPORT_CHARDEV,
  	HVUTIL_TRANSPORT_DESTROY,
  };
  
  struct hvutil_transport {
  	int mode;                           /* hvutil_transport_mode */
  	struct file_operations fops;        /* file operations */
  	struct miscdevice mdev;             /* misc device */
  	struct cb_id cn_id;                 /* CN_*_IDX/CN_*_VAL */
  	struct list_head list;              /* hvt_list */
  	int (*on_msg)(void *, int);         /* callback on new user message */
  	void (*on_reset)(void);             /* callback when userspace drops */
  	u8 *outmsg;                         /* message to the userspace */
  	int outmsg_len;                     /* its length */
  	wait_queue_head_t outmsg_q;         /* poll/read wait queue */
  	struct mutex lock;                  /* protects struct members */
  };
  
  struct hvutil_transport *hvutil_transport_init(const char *name,
  					       u32 cn_idx, u32 cn_val,
  					       int (*on_msg)(void *, int),
  					       void (*on_reset)(void));
  int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len);
  void hvutil_transport_destroy(struct hvutil_transport *hvt);
  
  #endif /* _HV_UTILS_TRANSPORT_H */
  