root/include/linux/nbd.h

INCLUDED FROM

/*
 * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL.
 * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne)
 *            Made nbd_end_request() use the io_request_lock
 * 2001 Copyright (C) Steven Whitehouse
 *            New nbd_end_request() for compatibility with new linux block
 *            layer code.
 * 2003/06/24 Louis D. Langholtz <ldl@aros.net>
 *            Removed unneeded blksize_bits field from nbd_device struct.
 *            Cleanup PARANOIA usage & code.
 * 2004/02/19 Paul Clements
 *            Removed PARANOIA, plus various cleanup and comments
 */

#ifndef LINUX_NBD_H
#define LINUX_NBD_H

#include <linux/types.h>

#define NBD_SET_SOCK    _IO( 0xab, 0 )
#define NBD_SET_BLKSIZE _IO( 0xab, 1 )
#define NBD_SET_SIZE    _IO( 0xab, 2 )
#define NBD_DO_IT       _IO( 0xab, 3 )
#define NBD_CLEAR_SOCK  _IO( 0xab, 4 )
#define NBD_CLEAR_QUE   _IO( 0xab, 5 )
#define NBD_PRINT_DEBUG _IO( 0xab, 6 )
#define NBD_SET_SIZE_BLOCKS     _IO( 0xab, 7 )
#define NBD_DISCONNECT  _IO( 0xab, 8 )
#define NBD_SET_TIMEOUT _IO( 0xab, 9 )

enum {
        NBD_CMD_READ = 0,
        NBD_CMD_WRITE = 1,
        NBD_CMD_DISC = 2
};

#define nbd_cmd(req) ((req)->cmd[0])

/* userspace doesn't need the nbd_device structure */
#ifdef __KERNEL__

#include <linux/wait.h>
#include <linux/mutex.h>

/* values for flags field */
#define NBD_READ_ONLY 0x0001
#define NBD_WRITE_NOCHK 0x0002

struct request;

struct nbd_device {
        int flags;
        int harderror;          /* Code of hard error                   */
        struct socket * sock;
        struct file * file;     /* If == NULL, device is not ready, yet */
        int magic;

        spinlock_t queue_lock;
        struct list_head queue_head;    /* Requests waiting result */
        struct request *active_req;
        wait_queue_head_t active_wq;
        struct list_head waiting_queue; /* Requests to be sent */
        wait_queue_head_t waiting_wq;

        struct mutex tx_lock;
        struct gendisk *disk;
        int blksize;
        u64 bytesize;
        pid_t pid; /* pid of nbd-client, if attached */
        int xmit_timeout;
};

#endif

/* These are sent over the network in the request/reply magic fields */

#define NBD_REQUEST_MAGIC 0x25609513
#define NBD_REPLY_MAGIC 0x67446698
/* Do *not* use magics: 0x12560953 0x96744668. */

/*
 * This is the packet used for communication between client and
 * server. All data are in network byte order.
 */
struct nbd_request {
        __be32 magic;
        __be32 type;    /* == READ || == WRITE  */
        char handle[8];
        __be64 from;
        __be32 len;
} __attribute__ ((packed));

/*
 * This is the reply packet that nbd-server sends back to the client after
 * it has completed an I/O request (or an error occurs).
 */
struct nbd_reply {
        __be32 magic;
        __be32 error;           /* 0 = ok, else error   */
        char handle[8];         /* handle you got from request  */
};
#endif