/*
   * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL.
   * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne)
   *            Made nbd_end_request() use the io_request_lock
   * 2001 Copyright (C) Steven Whitehouse
   *            New nbd_end_request() for compatibility with new linux block
   *            layer code.
   * 2003/06/24 Louis D. Langholtz <ldl@aros.net>
   *            Removed unneeded blksize_bits field from nbd_device struct.
   *            Cleanup PARANOIA usage & code.
   * 2004/02/19 Paul Clements
   *            Removed PARANOIA, plus various cleanup and comments
   */
  
  #ifndef LINUX_NBD_H
  #define LINUX_NBD_H

  #include <linux/types.h>

  #define NBD_SET_SOCK	_IO( 0xab, 0 )
  #define NBD_SET_BLKSIZE	_IO( 0xab, 1 )
  #define NBD_SET_SIZE	_IO( 0xab, 2 )
  #define NBD_DO_IT	_IO( 0xab, 3 )
  #define NBD_CLEAR_SOCK	_IO( 0xab, 4 )
  #define NBD_CLEAR_QUE	_IO( 0xab, 5 )
  #define NBD_PRINT_DEBUG	_IO( 0xab, 6 )
  #define NBD_SET_SIZE_BLOCKS	_IO( 0xab, 7 )
  #define NBD_DISCONNECT  _IO( 0xab, 8 )

  #define NBD_SET_TIMEOUT _IO( 0xab, 9 )

  
  enum {
  	NBD_CMD_READ = 0,
  	NBD_CMD_WRITE = 1,
  	NBD_CMD_DISC = 2
  };
  
  #define nbd_cmd(req) ((req)->cmd[0])

  
  /* userspace doesn't need the nbd_device structure */
  #ifdef __KERNEL__

  #include <linux/wait.h>

  #include <linux/mutex.h>

  /* values for flags field */
  #define NBD_READ_ONLY 0x0001
  #define NBD_WRITE_NOCHK 0x0002

  struct request;

  struct nbd_device {
  	int flags;
  	int harderror;		/* Code of hard error			*/
  	struct socket * sock;
  	struct file * file; 	/* If == NULL, device is not ready, yet	*/
  	int magic;

  	spinlock_t queue_lock;

  	struct list_head queue_head;	/* Requests waiting result */

  	struct request *active_req;
  	wait_queue_head_t active_wq;

  	struct list_head waiting_queue;	/* Requests to be sent */
  	wait_queue_head_t waiting_wq;

  	struct mutex tx_lock;

  	struct gendisk *disk;
  	int blksize;
  	u64 bytesize;

  	pid_t pid; /* pid of nbd-client, if attached */

  	int xmit_timeout;

  };
  
  #endif
  
  /* These are sent over the network in the request/reply magic fields */
  
  #define NBD_REQUEST_MAGIC 0x25609513
  #define NBD_REPLY_MAGIC 0x67446698
  /* Do *not* use magics: 0x12560953 0x96744668. */
  
  /*
   * This is the packet used for communication between client and
   * server. All data are in network byte order.
   */
  struct nbd_request {

  	__be32 magic;
  	__be32 type;	/* == READ || == WRITE 	*/

  	char handle[8];

  	__be64 from;
  	__be32 len;

  } __attribute__((packed));

  
  /*
   * This is the reply packet that nbd-server sends back to the client after
   * it has completed an I/O request (or an error occurs).
   */
  struct nbd_reply {

  	__be32 magic;
  	__be32 error;		/* 0 = ok, else error	*/

  	char handle[8];		/* handle you got from request	*/
  };
  #endif