xref: /linux-6.15/include/uapi/linux/nbd.h (revision e00a844a)
1 /* SPDX-License-Identifier: GPL-1.0+ WITH Linux-syscall-note */
2 /*
3  * 1999 Copyright (C) Pavel Machek, [email protected]. 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 <[email protected]>
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  */
15 
16 #ifndef _UAPILINUX_NBD_H
17 #define _UAPILINUX_NBD_H
18 
19 #include <linux/types.h>
20 
21 #define NBD_SET_SOCK	_IO( 0xab, 0 )
22 #define NBD_SET_BLKSIZE	_IO( 0xab, 1 )
23 #define NBD_SET_SIZE	_IO( 0xab, 2 )
24 #define NBD_DO_IT	_IO( 0xab, 3 )
25 #define NBD_CLEAR_SOCK	_IO( 0xab, 4 )
26 #define NBD_CLEAR_QUE	_IO( 0xab, 5 )
27 #define NBD_PRINT_DEBUG	_IO( 0xab, 6 )
28 #define NBD_SET_SIZE_BLOCKS	_IO( 0xab, 7 )
29 #define NBD_DISCONNECT  _IO( 0xab, 8 )
30 #define NBD_SET_TIMEOUT _IO( 0xab, 9 )
31 #define NBD_SET_FLAGS   _IO( 0xab, 10)
32 
33 enum {
34 	NBD_CMD_READ = 0,
35 	NBD_CMD_WRITE = 1,
36 	NBD_CMD_DISC = 2,
37 	NBD_CMD_FLUSH = 3,
38 	NBD_CMD_TRIM = 4
39 };
40 
41 /* values for flags field, these are server interaction specific. */
42 #define NBD_FLAG_HAS_FLAGS	(1 << 0) /* nbd-server supports flags */
43 #define NBD_FLAG_READ_ONLY	(1 << 1) /* device is read-only */
44 #define NBD_FLAG_SEND_FLUSH	(1 << 2) /* can flush writeback cache */
45 #define NBD_FLAG_SEND_FUA	(1 << 3) /* send FUA (forced unit access) */
46 /* there is a gap here to match userspace */
47 #define NBD_FLAG_SEND_TRIM	(1 << 5) /* send trim/discard */
48 #define NBD_FLAG_CAN_MULTI_CONN	(1 << 8)	/* Server supports multiple connections per export. */
49 
50 /* values for cmd flags in the upper 16 bits of request type */
51 #define NBD_CMD_FLAG_FUA	(1 << 16) /* FUA (forced unit access) op */
52 
53 /* These are client behavior specific flags. */
54 #define NBD_CFLAG_DESTROY_ON_DISCONNECT	(1 << 0) /* delete the nbd device on
55 						    disconnect. */
56 
57 /* userspace doesn't need the nbd_device structure */
58 
59 /* These are sent over the network in the request/reply magic fields */
60 
61 #define NBD_REQUEST_MAGIC 0x25609513
62 #define NBD_REPLY_MAGIC 0x67446698
63 /* Do *not* use magics: 0x12560953 0x96744668. */
64 
65 /*
66  * This is the packet used for communication between client and
67  * server. All data are in network byte order.
68  */
69 struct nbd_request {
70 	__be32 magic;
71 	__be32 type;	/* == READ || == WRITE 	*/
72 	char handle[8];
73 	__be64 from;
74 	__be32 len;
75 } __attribute__((packed));
76 
77 /*
78  * This is the reply packet that nbd-server sends back to the client after
79  * it has completed an I/O request (or an error occurs).
80  */
81 struct nbd_reply {
82 	__be32 magic;
83 	__be32 error;		/* 0 = ok, else error	*/
84 	char handle[8];		/* handle you got from request	*/
85 };
86 #endif /* _UAPILINUX_NBD_H */
87