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      1 /*
      2  * include/linux/nfsd/nfsfh.h
      3  *
      4  * This file describes the layout of the file handles as passed
      5  * over the wire.
      6  *
      7  * Earlier versions of knfsd used to sign file handles using keyed MD5
      8  * or SHA. I've removed this code, because it doesn't give you more
      9  * security than blocking external access to port 2049 on your firewall.
     10  *
     11  * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir (at) monad.swb.de>
     12  */
     13 
     14 #ifndef _LINUX_NFSD_FH_H
     15 #define _LINUX_NFSD_FH_H
     16 
     17 #include <asm/types.h>
     18 #include <linux/nfsd/const.h>
     19 #include <linux/nfsd/debug.h>
     20 
     21 /*
     22  * This is the old "dentry style" Linux NFSv2 file handle.
     23  *
     24  * The xino and xdev fields are currently used to transport the
     25  * ino/dev of the exported inode.
     26  */
     27 struct nfs_fhbase_old {
     28 	__u32		fb_dcookie;	/* dentry cookie - always 0xfeebbaca */
     29 	__u32		fb_ino;		/* our inode number */
     30 	__u32		fb_dirino;	/* dir inode number, 0 for directories */
     31 	__u32		fb_dev;		/* our device */
     32 	__u32		fb_xdev;
     33 	__u32		fb_xino;
     34 	__u32		fb_generation;
     35 };
     36 
     37 /*
     38  * This is the new flexible, extensible style NFSv2/v3 file handle.
     39  * by Neil Brown <neilb (at) cse.unsw.edu.au> - March 2000
     40  *
     41  * The file handle is seens as a list of 4byte words.
     42  * The first word contains a version number (1) and four descriptor bytes
     43  * that tell how the remaining 3 variable length fields should be handled.
     44  * These three bytes are auth_type, fsid_type and fileid_type.
     45  *
     46  * All 4byte values are in host-byte-order.
     47  *
     48  * The auth_type field specifies how the filehandle can be authenticated
     49  * This might allow a file to be confirmed to be in a writable part of a
     50  * filetree without checking the path from it upto the root.
     51  * Current values:
     52  *     0  - No authentication.  fb_auth is 0 bytes long
     53  * Possible future values:
     54  *     1  - 4 bytes taken from MD5 hash of the remainer of the file handle
     55  *          prefixed by a secret and with the important export flags.
     56  *
     57  * The fsid_type identifies how the filesystem (or export point) is
     58  *    encoded.
     59  *  Current values:
     60  *     0  - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
     61  *        NOTE: we cannot use the kdev_t device id value, because kdev_t.h
     62  *              says we mustn't.  We must break it up and reassemble.
     63  *     1  - 4 byte user specified identifier
     64  *     2  - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
     65  *     3  - 4 byte device id, encoded for user-space, 4 byte inode number
     66  *
     67  * The fileid_type identified how the file within the filesystem is encoded.
     68  * This is (will be) passed to, and set by, the underlying filesystem if it supports
     69  * filehandle operations.  The filesystem must not use the value '0' or '0xff' and may
     70  * only use the values 1 and 2 as defined below:
     71  *  Current values:
     72  *    0   - The root, or export point, of the filesystem.  fb_fileid is 0 bytes.
     73  *    1   - 32bit inode number, 32 bit generation number.
     74  *    2   - 32bit inode number, 32 bit generation number, 32 bit parent directory inode number.
     75  *
     76  */
     77 struct nfs_fhbase_new {
     78 	__u8		fb_version;	/* == 1, even => nfs_fhbase_old */
     79 	__u8		fb_auth_type;
     80 	__u8		fb_fsid_type;
     81 	__u8		fb_fileid_type;
     82 	__u32		fb_auth[1];
     83 /*	__u32		fb_fsid[0]; floating */
     84 /*	__u32		fb_fileid[0]; floating */
     85 };
     86 
     87 struct knfsd_fh {
     88 	unsigned int	fh_size;	/* significant for NFSv3.
     89 					 * Points to the current size while building
     90 					 * a new file handle
     91 					 */
     92 	union {
     93 		struct nfs_fhbase_old	fh_old;
     94 		__u32			fh_pad[NFS4_FHSIZE/4];
     95 		struct nfs_fhbase_new	fh_new;
     96 	} fh_base;
     97 };
     98 
     99 #define ofh_dcookie		fh_base.fh_old.fb_dcookie
    100 #define ofh_ino			fh_base.fh_old.fb_ino
    101 #define ofh_dirino		fh_base.fh_old.fb_dirino
    102 #define ofh_dev			fh_base.fh_old.fb_dev
    103 #define ofh_xdev		fh_base.fh_old.fb_xdev
    104 #define ofh_xino		fh_base.fh_old.fb_xino
    105 #define ofh_generation		fh_base.fh_old.fb_generation
    106 
    107 #define	fh_version		fh_base.fh_new.fb_version
    108 #define	fh_fsid_type		fh_base.fh_new.fb_fsid_type
    109 #define	fh_auth_type		fh_base.fh_new.fb_auth_type
    110 #define	fh_fileid_type		fh_base.fh_new.fb_fileid_type
    111 #define	fh_auth			fh_base.fh_new.fb_auth
    112 #define	fh_fsid			fh_base.fh_new.fb_auth
    113 
    114 
    115 
    116 #endif /* _LINUX_NFSD_FH_H */
    117