linux-headers (unknown)
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 LINUX_NBD_H
19 #define LINUX_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
40 enum {
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 */
81 struct 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 */
96 struct 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 /* LINUX_NBD_H */
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