include/uapi/linux/nbd.h

   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
  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         NBD_CMD_WRITE_ZEROES = 6,
  48 };
  49
  50 /* values for flags field, these are server interaction specific. */
  51 #define NBD_FLAG_HAS_FLAGS      (1 << 0) /* nbd-server supports flags */
  52 #define NBD_FLAG_READ_ONLY      (1 << 1) /* device is read-only */
  53 #define NBD_FLAG_SEND_FLUSH     (1 << 2) /* can flush writeback cache */
  54 #define NBD_FLAG_SEND_FUA       (1 << 3) /* send FUA (forced unit access) */
  55 #define NBD_FLAG_ROTATIONAL     (1 << 4) /* device is rotational */
  56 #define NBD_FLAG_SEND_TRIM      (1 << 5) /* send trim/discard */
  57 #define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* supports WRITE_ZEROES */
  58 /* there is a gap here to match userspace */
  59 #define NBD_FLAG_CAN_MULTI_CONN (1 << 8)        /* Server supports multiple connections per export. */
  60
  61 /* values for cmd flags in the upper 16 bits of request type */
  62 #define NBD_CMD_FLAG_FUA        (1 << 16) /* FUA (forced unit access) op */
  63 #define NBD_CMD_FLAG_NO_HOLE    (1 << 17) /* Do not punch a hole for WRITE_ZEROES */
  64
  65 /* These are client behavior specific flags. */
  66 #define NBD_CFLAG_DESTROY_ON_DISCONNECT (1 << 0) /* delete the nbd device on
  67                                                     disconnect. */
  68 #define NBD_CFLAG_DISCONNECT_ON_CLOSE (1 << 1) /* disconnect the nbd device on
  69                                                 *  close by last opener.
  70                                                 */
  71
  72 /* userspace doesn't need the nbd_device structure */
  73
  74 /* These are sent over the network in the request/reply magic fields */
  75
  76 #define NBD_REQUEST_MAGIC 0x25609513
  77 #define NBD_REPLY_MAGIC 0x67446698
  78 /* Do *not* use magics: 0x12560953 0x96744668. */
  79 /* magic 0x668e33ef for structured reply not supported by kernel yet */
  80
  81 /*
  82  * This is the packet used for communication between client and
  83  * server. All data are in network byte order.
  84  */
  85 struct nbd_request {
  86         __be32 magic;   /* NBD_REQUEST_MAGIC    */
  87         __be32 type;    /* See NBD_CMD_*        */
  88         union {
  89                 __be64 cookie;  /* Opaque identifier for request        */
  90                 char handle[8]; /* older spelling of cookie             */
  91         };
  92         __be64 from;
  93         __be32 len;
  94 } __attribute__((packed));
  95
  96 /*
  97  * This is the reply packet that nbd-server sends back to the client after
  98  * it has completed an I/O request (or an error occurs).
  99  */
 100 struct nbd_reply {
 101         __be32 magic;           /* NBD_REPLY_MAGIC      */
 102         __be32 error;           /* 0 = ok, else error   */
 103         union {
 104                 __be64 cookie;  /* Opaque identifier from request       */
 105                 char handle[8]; /* older spelling of cookie             */
 106         };
 107 };
 108 #endif /* _UAPILINUX_NBD_H */