1/* SPDX-License-Identifier: GPL-1.0+ WITH Linux-syscall-note */
2/*
3 * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL.
4 * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne)
5 *            Made nbd_end_request() use the io_request_lock
6 * 2001 Copyright (C) Steven Whitehouse
7 *            New nbd_end_request() for compatibility with new linux block
8 *            layer code.
9 * 2003/06/24 Louis D. Langholtz <ldl@aros.net>
10 *            Removed unneeded blksize_bits field from nbd_device struct.
11 *            Cleanup PARANOIA usage & code.
12 * 2004/02/19 Paul Clements
13 *            Removed PARANOIA, plus various cleanup and comments
14 * 2023 Copyright Red Hat
15 *            Link to userspace extensions, favor cookie over handle.
16 */
17
18#ifndef _UAPILINUX_NBD_H
19#define _UAPILINUX_NBD_H
20
21#include <linux/types.h>
22
23#define NBD_SET_SOCK	_IO( 0xab, 0 )
24#define NBD_SET_BLKSIZE	_IO( 0xab, 1 )
25#define NBD_SET_SIZE	_IO( 0xab, 2 )
26#define NBD_DO_IT	_IO( 0xab, 3 )
27#define NBD_CLEAR_SOCK	_IO( 0xab, 4 )
28#define NBD_CLEAR_QUE	_IO( 0xab, 5 )
29#define NBD_PRINT_DEBUG	_IO( 0xab, 6 )
30#define NBD_SET_SIZE_BLOCKS	_IO( 0xab, 7 )
31#define NBD_DISCONNECT  _IO( 0xab, 8 )
32#define NBD_SET_TIMEOUT _IO( 0xab, 9 )
33#define NBD_SET_FLAGS   _IO( 0xab, 10)
34
35/*
36 * See also https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md
37 * for additional userspace extensions not yet utilized in the kernel module.
38 */
39
40enum {
41	NBD_CMD_READ = 0,
42	NBD_CMD_WRITE = 1,
43	NBD_CMD_DISC = 2,
44	NBD_CMD_FLUSH = 3,
45	NBD_CMD_TRIM = 4
46	/* userspace defines additional extension commands */
47};
48
49/* values for flags field, these are server interaction specific. */
50#define NBD_FLAG_HAS_FLAGS	(1 << 0) /* nbd-server supports flags */
51#define NBD_FLAG_READ_ONLY	(1 << 1) /* device is read-only */
52#define NBD_FLAG_SEND_FLUSH	(1 << 2) /* can flush writeback cache */
53#define NBD_FLAG_SEND_FUA	(1 << 3) /* send FUA (forced unit access) */
54/* there is a gap here to match userspace */
55#define NBD_FLAG_SEND_TRIM	(1 << 5) /* send trim/discard */
56#define NBD_FLAG_CAN_MULTI_CONN	(1 << 8)	/* Server supports multiple connections per export. */
57
58/* values for cmd flags in the upper 16 bits of request type */
59#define NBD_CMD_FLAG_FUA	(1 << 16) /* FUA (forced unit access) op */
60
61/* These are client behavior specific flags. */
62#define NBD_CFLAG_DESTROY_ON_DISCONNECT	(1 << 0) /* delete the nbd device on
63						    disconnect. */
64#define NBD_CFLAG_DISCONNECT_ON_CLOSE (1 << 1) /* disconnect the nbd device on
65						*  close by last opener.
66						*/
67
68/* userspace doesn't need the nbd_device structure */
69
70/* These are sent over the network in the request/reply magic fields */
71
72#define NBD_REQUEST_MAGIC 0x25609513
73#define NBD_REPLY_MAGIC 0x67446698
74/* Do *not* use magics: 0x12560953 0x96744668. */
75/* magic 0x668e33ef for structured reply not supported by kernel yet */
76
77/*
78 * This is the packet used for communication between client and
79 * server. All data are in network byte order.
80 */
81struct nbd_request {
82	__be32 magic;	/* NBD_REQUEST_MAGIC	*/
83	__be32 type;	/* See NBD_CMD_*	*/
84	union {
85		__be64 cookie;	/* Opaque identifier for request	*/
86		char handle[8];	/* older spelling of cookie		*/
87	};
88	__be64 from;
89	__be32 len;
90} __attribute__((packed));
91
92/*
93 * This is the reply packet that nbd-server sends back to the client after
94 * it has completed an I/O request (or an error occurs).
95 */
96struct nbd_reply {
97	__be32 magic;		/* NBD_REPLY_MAGIC	*/
98	__be32 error;		/* 0 = ok, else error	*/
99	union {
100		__be64 cookie;	/* Opaque identifier from request	*/
101		char handle[8];	/* older spelling of cookie		*/
102	};
103};
104#endif /* _UAPILINUX_NBD_H */
105