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      1 /*
      2  * 1999 Copyright (C) Pavel Machek, pavel (at) 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 (at) 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 #include <linux/types.h>
     19 
     20 #define NBD_SET_SOCK	_IO( 0xab, 0 )
     21 #define NBD_SET_BLKSIZE	_IO( 0xab, 1 )
     22 #define NBD_SET_SIZE	_IO( 0xab, 2 )
     23 #define NBD_DO_IT	_IO( 0xab, 3 )
     24 #define NBD_CLEAR_SOCK	_IO( 0xab, 4 )
     25 #define NBD_CLEAR_QUE	_IO( 0xab, 5 )
     26 #define NBD_PRINT_DEBUG	_IO( 0xab, 6 )
     27 #define NBD_SET_SIZE_BLOCKS	_IO( 0xab, 7 )
     28 #define NBD_DISCONNECT  _IO( 0xab, 8 )
     29 #define NBD_SET_TIMEOUT _IO( 0xab, 9 )
     30 
     31 enum {
     32 	NBD_CMD_READ = 0,
     33 	NBD_CMD_WRITE = 1,
     34 	NBD_CMD_DISC = 2
     35 };
     36 
     37 #define nbd_cmd(req) ((req)->cmd[0])
     38 #define MAX_NBD 128
     39 
     40 /* userspace doesn't need the nbd_device structure */
     41 
     42 /* These are sent over the network in the request/reply magic fields */
     43 
     44 #define NBD_REQUEST_MAGIC 0x25609513
     45 #define NBD_REPLY_MAGIC 0x67446698
     46 /* Do *not* use magics: 0x12560953 0x96744668. */
     47 
     48 /*
     49  * This is the packet used for communication between client and
     50  * server. All data are in network byte order.
     51  */
     52 struct nbd_request {
     53 	__be32 magic;
     54 	__be32 type;	/* == READ || == WRITE 	*/
     55 	char handle[8];
     56 	__be64 from;
     57 	__be32 len;
     58 }
     59 #ifdef __GNUC__
     60 	__attribute__ ((packed))
     61 #endif
     62 ;
     63 
     64 /*
     65  * This is the reply packet that nbd-server sends back to the client after
     66  * it has completed an I/O request (or an error occurs).
     67  */
     68 struct nbd_reply {
     69 	__be32 magic;
     70 	__be32 error;		/* 0 = ok, else error	*/
     71 	char handle[8];		/* handle you got from request	*/
     72 };
     73 #endif
     74