1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 1995, 1996, 1997 Olaf Kirch <okir@monad.swb.de>
4 *
5 * This file describes the layout of the file handles as passed
6 * over the wire.
7 */
8 #ifndef _LINUX_NFSD_NFSFH_H
9 #define _LINUX_NFSD_NFSFH_H
10
11 #include <linux/crc32.h>
12 #include <linux/sunrpc/svc.h>
13 #include <linux/iversion.h>
14 #include <linux/exportfs.h>
15 #include <linux/nfs4.h>
16
17 /*
18 * The file handle starts with a sequence of four-byte words.
19 * The first word contains a version number (1) and three descriptor bytes
20 * that tell how the remaining 3 variable length fields should be handled.
21 * These three bytes are auth_type, fsid_type and fileid_type.
22 *
23 * All four-byte values are in host-byte-order.
24 *
25 * The auth_type field is deprecated and must be set to 0.
26 *
27 * The fsid_type identifies how the filesystem (or export point) is
28 * encoded.
29 * Current values:
30 * 0 - 4 byte device id (ms-2-bytes major, ls-2-bytes minor), 4byte inode number
31 * NOTE: we cannot use the kdev_t device id value, because kdev_t.h
32 * says we mustn't. We must break it up and reassemble.
33 * 1 - 4 byte user specified identifier
34 * 2 - 4 byte major, 4 byte minor, 4 byte inode number - DEPRECATED
35 * 3 - 4 byte device id, encoded for user-space, 4 byte inode number
36 * 4 - 4 byte inode number and 4 byte uuid
37 * 5 - 8 byte uuid
38 * 6 - 16 byte uuid
39 * 7 - 8 byte inode number and 16 byte uuid
40 *
41 * The fileid_type identifies how the file within the filesystem is encoded.
42 * The values for this field are filesystem specific, exccept that
43 * filesystems must not use the values '' or '0xff'. 'See enum fid_type'
44 * in include/linux/exportfs.h for currently registered values.
45 */
46
47 struct knfsd_fh {
48 unsigned int fh_size; /*
49 * Points to the current size while
50 * building a new file handle.
51 */
52 union {
53 char fh_raw[NFS4_FHSIZE];
54 struct {
55 u8 fh_version; /* == 1 */
56 u8 fh_auth_type; /* deprecated */
57 u8 fh_fsid_type;
58 u8 fh_fileid_type;
59 u32 fh_fsid[]; /* flexible-array member */
60 };
61 };
62 };
63
64 static inline __u32 ino_t_to_u32(ino_t ino)
65 {
66 return (__u32) ino;
67 }
68
69 static inline ino_t u32_to_ino_t(__u32 uino)
70 {
71 return (ino_t) uino;
72 }
73
74 /*
75 * This is the internal representation of an NFS handle used in knfsd.
76 * pre_mtime/post_version will be used to support wcc_attr's in NFSv3.
77 */
78 typedef struct svc_fh {
79 struct knfsd_fh fh_handle; /* FH data */
80 int fh_maxsize; /* max size for fh_handle */
81 struct dentry * fh_dentry; /* validated dentry */
82 struct svc_export * fh_export; /* export pointer */
83
84 bool fh_want_write; /* remount protection taken */
85 bool fh_no_wcc; /* no wcc data needed */
86 bool fh_no_atomic_attr;
87 /*
88 * wcc data is not atomic with
89 * operation
90 */
91 int fh_flags; /* FH flags */
92 bool fh_post_saved; /* post-op attrs saved */
93 bool fh_pre_saved; /* pre-op attrs saved */
94
95 /* Pre-op attributes saved when inode is locked */
96 __u64 fh_pre_size; /* size before operation */
97 struct timespec64 fh_pre_mtime; /* mtime before oper */
98 struct timespec64 fh_pre_ctime; /* ctime before oper */
99 /*
100 * pre-op nfsv4 change attr: note must check IS_I_VERSION(inode)
101 * to find out if it is valid.
102 */
103 u64 fh_pre_change;
104
105 /* Post-op attributes saved in fh_fill_post_attrs() */
106 struct kstat fh_post_attr; /* full attrs after operation */
107 u64 fh_post_change; /* nfsv4 change; see above */
108 } svc_fh;
109 #define NFSD4_FH_FOREIGN (1<<0)
110 #define SET_FH_FLAG(c, f) ((c)->fh_flags |= (f))
111 #define HAS_FH_FLAG(c, f) ((c)->fh_flags & (f))
112
113 enum nfsd_fsid {
114 FSID_DEV = 0,
115 FSID_NUM,
116 FSID_MAJOR_MINOR,
117 FSID_ENCODE_DEV,
118 FSID_UUID4_INUM,
119 FSID_UUID8,
120 FSID_UUID16,
121 FSID_UUID16_INUM,
122 };
123
124 enum fsid_source {
125 FSIDSOURCE_DEV,
126 FSIDSOURCE_FSID,
127 FSIDSOURCE_UUID,
128 };
129 extern enum fsid_source fsid_source(const struct svc_fh *fhp);
130
131
132 /*
133 * This might look a little large to "inline" but in all calls except
134 * one, 'vers' is constant so moste of the function disappears.
135 *
136 * In some cases the values are considered to be host endian and in
137 * others, net endian. fsidv is always considered to be u32 as the
138 * callers don't know which it will be. So we must use __force to keep
139 * sparse from complaining. Since these values are opaque to the
140 * client, that shouldn't be a problem.
141 */
142 static inline void mk_fsid(int vers, u32 *fsidv, dev_t dev, ino_t ino,
143 u32 fsid, unsigned char *uuid)
144 {
145 u32 *up;
146 switch(vers) {
147 case FSID_DEV:
148 fsidv[0] = (__force __u32)htonl((MAJOR(dev)<<16) |
149 MINOR(dev));
150 fsidv[1] = ino_t_to_u32(ino);
151 break;
152 case FSID_NUM:
153 fsidv[0] = fsid;
154 break;
155 case FSID_MAJOR_MINOR:
156 fsidv[0] = (__force __u32)htonl(MAJOR(dev));
157 fsidv[1] = (__force __u32)htonl(MINOR(dev));
158 fsidv[2] = ino_t_to_u32(ino);
159 break;
160
161 case FSID_ENCODE_DEV:
162 fsidv[0] = new_encode_dev(dev);
163 fsidv[1] = ino_t_to_u32(ino);
164 break;
165
166 case FSID_UUID4_INUM:
167 /* 4 byte fsid and inode number */
168 up = (u32*)uuid;
169 fsidv[0] = ino_t_to_u32(ino);
170 fsidv[1] = up[0] ^ up[1] ^ up[2] ^ up[3];
171 break;
172
173 case FSID_UUID8:
174 /* 8 byte fsid */
175 up = (u32*)uuid;
176 fsidv[0] = up[0] ^ up[2];
177 fsidv[1] = up[1] ^ up[3];
178 break;
179
180 case FSID_UUID16:
181 /* 16 byte fsid - NFSv3+ only */
182 memcpy(fsidv, uuid, 16);
183 break;
184
185 case FSID_UUID16_INUM:
186 /* 8 byte inode and 16 byte fsid */
187 *(u64*)fsidv = (u64)ino;
188 memcpy(fsidv+2, uuid, 16);
189 break;
190 default: BUG();
191 }
192 }
193
194 static inline int key_len(int type)
195 {
196 switch(type) {
197 case FSID_DEV: return 8;
198 case FSID_NUM: return 4;
199 case FSID_MAJOR_MINOR: return 12;
200 case FSID_ENCODE_DEV: return 8;
201 case FSID_UUID4_INUM: return 8;
202 case FSID_UUID8: return 8;
203 case FSID_UUID16: return 16;
204 case FSID_UUID16_INUM: return 24;
205 default: return 0;
206 }
207 }
208
209 /*
210 * Shorthand for dprintk()'s
211 */
212 extern char * SVCFH_fmt(struct svc_fh *fhp);
213
214 /*
215 * Function prototypes
216 */
217 __be32 fh_verify(struct svc_rqst *, struct svc_fh *, umode_t, int);
218 __be32 fh_compose(struct svc_fh *, struct svc_export *, struct dentry *, struct svc_fh *);
219 __be32 fh_update(struct svc_fh *);
220 void fh_put(struct svc_fh *);
221
222 static __inline__ struct svc_fh *
223 fh_copy(struct svc_fh *dst, const struct svc_fh *src)
224 {
225 WARN_ON(src->fh_dentry);
226
227 *dst = *src;
228 return dst;
229 }
230
231 static inline void
232 fh_copy_shallow(struct knfsd_fh *dst, const struct knfsd_fh *src)
233 {
234 dst->fh_size = src->fh_size;
235 memcpy(&dst->fh_raw, &src->fh_raw, src->fh_size);
236 }
237
238 static __inline__ struct svc_fh *
239 fh_init(struct svc_fh *fhp, int maxsize)
240 {
241 memset(fhp, 0, sizeof(*fhp));
242 fhp->fh_maxsize = maxsize;
243 return fhp;
244 }
245
246 static inline bool fh_match(const struct knfsd_fh *fh1,
247 const struct knfsd_fh *fh2)
248 {
249 if (fh1->fh_size != fh2->fh_size)
250 return false;
251 if (memcmp(fh1->fh_raw, fh2->fh_raw, fh1->fh_size) != 0)
252 return false;
253 return true;
254 }
255
256 static inline bool fh_fsid_match(const struct knfsd_fh *fh1,
257 const struct knfsd_fh *fh2)
258 {
259 if (fh1->fh_fsid_type != fh2->fh_fsid_type)
260 return false;
261 if (memcmp(fh1->fh_fsid, fh2->fh_fsid, key_len(fh1->fh_fsid_type)) != 0)
262 return false;
263 return true;
264 }
265
266 #ifdef CONFIG_CRC32
267 /**
268 * knfsd_fh_hash - calculate the crc32 hash for the filehandle
269 * @fh - pointer to filehandle
270 *
271 * returns a crc32 hash for the filehandle that is compatible with
272 * the one displayed by "wireshark".
273 */
274 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
275 {
276 return ~crc32_le(0xFFFFFFFF, fh->fh_raw, fh->fh_size);
277 }
278 #else
279 static inline u32 knfsd_fh_hash(const struct knfsd_fh *fh)
280 {
281 return 0;
282 }
283 #endif
284
285 /**
286 * fh_clear_pre_post_attrs - Reset pre/post attributes
287 * @fhp: file handle to be updated
288 *
289 */
290 static inline void fh_clear_pre_post_attrs(struct svc_fh *fhp)
291 {
292 fhp->fh_post_saved = false;
293 fhp->fh_pre_saved = false;
294 }
295
296 u64 nfsd4_change_attribute(const struct kstat *stat,
297 const struct inode *inode);
298 __be32 __must_check fh_fill_pre_attrs(struct svc_fh *fhp);
299 __be32 fh_fill_post_attrs(struct svc_fh *fhp);
300 __be32 __must_check fh_fill_both_attrs(struct svc_fh *fhp);
301 #endif /* _LINUX_NFSD_NFSFH_H */
302
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