include/linux/nbd.h

   1 /*
   2  * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL.
   3  * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne)
   4  *            Made nbd_end_request() use the io_request_lock
   5  * 2001 Copyright (C) Steven Whitehouse
   6  *            New nbd_end_request() for compatibility with new linux block
   7  *            layer code.
   8  * 2003/06/24 Louis D. Langholtz <ldl@aros.net>
   9  *            Removed unneeded blksize_bits field from nbd_device struct.
  10  *            Cleanup PARANOIA usage & code.
  11  * 2004/02/19 Paul Clements
  12  *            Removed PARANOIA, plus various cleanup and comments
  13  */
  14
  15 #ifndef LINUX_NBD_H
  16 #define LINUX_NBD_H
  17
  18 #define NBD_SET_SOCK    _IO( 0xab, 0 )
  19 #define NBD_SET_BLKSIZE _IO( 0xab, 1 )
  20 #define NBD_SET_SIZE    _IO( 0xab, 2 )
  21 #define NBD_DO_IT       _IO( 0xab, 3 )
  22 #define NBD_CLEAR_SOCK  _IO( 0xab, 4 )
  23 #define NBD_CLEAR_QUE   _IO( 0xab, 5 )
  24 #define NBD_PRINT_DEBUG _IO( 0xab, 6 )
  25 #define NBD_SET_SIZE_BLOCKS     _IO( 0xab, 7 )
  26 #define NBD_DISCONNECT  _IO( 0xab, 8 )
  27
  28 enum {
  29         NBD_CMD_READ = 0,
  30         NBD_CMD_WRITE = 1,
  31         NBD_CMD_DISC = 2
  32 };
  33
  34 #define nbd_cmd(req) ((req)->cmd[0])
  35 #define MAX_NBD 128
  36
  37 /* userspace doesn't need the nbd_device structure */
  38 #ifdef __KERNEL__
  39
  40 /* values for flags field */
  41 #define NBD_READ_ONLY 0x0001
  42 #define NBD_WRITE_NOCHK 0x0002
  43
  44 struct nbd_device {
  45         int flags;
  46         int harderror;          /* Code of hard error                   */
  47         struct socket * sock;
  48         struct file * file;     /* If == NULL, device is not ready, yet */
  49         int magic;
  50         spinlock_t queue_lock;
  51         struct list_head queue_head;/* Requests are added here...       */
  52         struct semaphore tx_lock;
  53         struct gendisk *disk;
  54         int blksize;
  55         u64 bytesize;
  56 };
  57
  58 #endif
  59
  60 /* These are sent over the network in the request/reply magic fields */
  61
  62 #define NBD_REQUEST_MAGIC 0x25609513
  63 #define NBD_REPLY_MAGIC 0x67446698
  64 /* Do *not* use magics: 0x12560953 0x96744668. */
  65
  66 /*
  67  * This is the packet used for communication between client and
  68  * server. All data are in network byte order.
  69  */
  70 struct nbd_request {
  71         u32 magic;
  72         u32 type;       /* == READ || == WRITE  */
  73         char handle[8];
  74         u64 from;
  75         u32 len;
  76 }
  77 #ifdef __GNUC__
  78         __attribute__ ((packed))
  79 #endif
  80 ;
  81
  82 /*
  83  * This is the reply packet that nbd-server sends back to the client after
  84  * it has completed an I/O request (or an error occurs).
  85  */
  86 struct nbd_reply {
  87         u32 magic;
  88         u32 error;              /* 0 = ok, else error   */
  89         char handle[8];         /* handle you got from request  */
  90 };
  91 #endif