uapi/linux/nbd.h

0001 /* SPDX-License-Identifier: GPL-1.0+ WITH Linux-syscall-note */
0002 /*
0003  * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL.
0004  * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne)
0005  *            Made nbd_end_request() use the io_request_lock
0006  * 2001 Copyright (C) Steven Whitehouse
0007  *            New nbd_end_request() for compatibility with new linux block
0008  *            layer code.
0009  * 2003/06/24 Louis D. Langholtz <ldl@aros.net>
0010  *            Removed unneeded blksize_bits field from nbd_device struct.
0011  *            Cleanup PARANOIA usage & code.
0012  * 2004/02/19 Paul Clements
0013  *            Removed PARANOIA, plus various cleanup and comments
0014  */
0015
0016 #ifndef _UAPILINUX_NBD_H
0017 #define _UAPILINUX_NBD_H
0018
0019 #include <linux/types.h>
0020
0021 #define NBD_SET_SOCK    _IO( 0xab, 0 )
0022 #define NBD_SET_BLKSIZE _IO( 0xab, 1 )
0023 #define NBD_SET_SIZE    _IO( 0xab, 2 )
0024 #define NBD_DO_IT   _IO( 0xab, 3 )
0025 #define NBD_CLEAR_SOCK  _IO( 0xab, 4 )
0026 #define NBD_CLEAR_QUE   _IO( 0xab, 5 )
0027 #define NBD_PRINT_DEBUG _IO( 0xab, 6 )
0028 #define NBD_SET_SIZE_BLOCKS _IO( 0xab, 7 )
0029 #define NBD_DISCONNECT  _IO( 0xab, 8 )
0030 #define NBD_SET_TIMEOUT _IO( 0xab, 9 )
0031 #define NBD_SET_FLAGS   _IO( 0xab, 10)
0032
0033 enum {
0034     NBD_CMD_READ = 0,
0035     NBD_CMD_WRITE = 1,
0036     NBD_CMD_DISC = 2,
0037     NBD_CMD_FLUSH = 3,
0038     NBD_CMD_TRIM = 4
0039 };
0040
0041 /* values for flags field, these are server interaction specific. */
0042 #define NBD_FLAG_HAS_FLAGS  (1 << 0) /* nbd-server supports flags */
0043 #define NBD_FLAG_READ_ONLY  (1 << 1) /* device is read-only */
0044 #define NBD_FLAG_SEND_FLUSH (1 << 2) /* can flush writeback cache */
0045 #define NBD_FLAG_SEND_FUA   (1 << 3) /* send FUA (forced unit access) */
0046 /* there is a gap here to match userspace */
0047 #define NBD_FLAG_SEND_TRIM  (1 << 5) /* send trim/discard */
0048 #define NBD_FLAG_CAN_MULTI_CONN (1 << 8)    /* Server supports multiple connections per export. */
0049
0050 /* values for cmd flags in the upper 16 bits of request type */
0051 #define NBD_CMD_FLAG_FUA    (1 << 16) /* FUA (forced unit access) op */
0052
0053 /* These are client behavior specific flags. */
0054 #define NBD_CFLAG_DESTROY_ON_DISCONNECT (1 << 0) /* delete the nbd device on
0055                             disconnect. */
0056 #define NBD_CFLAG_DISCONNECT_ON_CLOSE (1 << 1) /* disconnect the nbd device on
0057                         *  close by last opener.
0058                         */
0059
0060 /* userspace doesn't need the nbd_device structure */
0061
0062 /* These are sent over the network in the request/reply magic fields */
0063
0064 #define NBD_REQUEST_MAGIC 0x25609513
0065 #define NBD_REPLY_MAGIC 0x67446698
0066 /* Do *not* use magics: 0x12560953 0x96744668. */
0067
0068 /*
0069  * This is the packet used for communication between client and
0070  * server. All data are in network byte order.
0071  */
0072 struct nbd_request {
0073     __be32 magic;
0074     __be32 type;    /* == READ || == WRITE  */
0075     char handle[8];
0076     __be64 from;
0077     __be32 len;
0078 } __attribute__((packed));
0079
0080 /*
0081  * This is the reply packet that nbd-server sends back to the client after
0082  * it has completed an I/O request (or an error occurs).
0083  */
0084 struct nbd_reply {
0085     __be32 magic;
0086     __be32 error;       /* 0 = ok, else error   */
0087     char handle[8];     /* handle you got from request  */
0088 };
0089 #endif /* _UAPILINUX_NBD_H */