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libceph: ceph_decode_skip_* helpers
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1#ifndef __CEPH_DECODE_H
2#define __CEPH_DECODE_H
3
f8c36c58 4#include <linux/err.h>
187f1882 5#include <linux/bug.h>
b2aa5d0b 6#include <linux/slab.h>
c7e337d6 7#include <linux/time.h>
187f1882 8#include <asm/unaligned.h>
31b8006e 9
a1ce3928 10#include <linux/ceph/types.h>
c89136ea 11
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12/*
13 * in all cases,
14 * void **p pointer to position pointer
15 * void *end pointer to end of buffer (last byte + 1)
16 */
17
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18static inline u64 ceph_decode_64(void **p)
19{
20 u64 v = get_unaligned_le64(*p);
21 *p += sizeof(u64);
22 return v;
23}
24static inline u32 ceph_decode_32(void **p)
25{
26 u32 v = get_unaligned_le32(*p);
27 *p += sizeof(u32);
28 return v;
29}
30static inline u16 ceph_decode_16(void **p)
31{
32 u16 v = get_unaligned_le16(*p);
33 *p += sizeof(u16);
34 return v;
35}
36static inline u8 ceph_decode_8(void **p)
37{
38 u8 v = *(u8 *)*p;
39 (*p)++;
40 return v;
41}
42static inline void ceph_decode_copy(void **p, void *pv, size_t n)
43{
44 memcpy(pv, *p, n);
45 *p += n;
46}
47
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48/*
49 * bounds check input.
50 */
3b33f692 51static inline bool ceph_has_room(void **p, void *end, size_t n)
76aa542f
XW
52{
53 return end >= *p && n <= end - *p;
54}
55
dd5f049d
AE
56#define ceph_decode_need(p, end, n, bad) \
57 do { \
58 if (!likely(ceph_has_room(p, end, n))) \
59 goto bad; \
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60 } while (0)
61
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62#define ceph_decode_64_safe(p, end, v, bad) \
63 do { \
64 ceph_decode_need(p, end, sizeof(u64), bad); \
c89136ea 65 v = ceph_decode_64(p); \
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66 } while (0)
67#define ceph_decode_32_safe(p, end, v, bad) \
68 do { \
69 ceph_decode_need(p, end, sizeof(u32), bad); \
c89136ea 70 v = ceph_decode_32(p); \
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71 } while (0)
72#define ceph_decode_16_safe(p, end, v, bad) \
73 do { \
74 ceph_decode_need(p, end, sizeof(u16), bad); \
c89136ea 75 v = ceph_decode_16(p); \
31b8006e 76 } while (0)
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77#define ceph_decode_8_safe(p, end, v, bad) \
78 do { \
79 ceph_decode_need(p, end, sizeof(u8), bad); \
80 v = ceph_decode_8(p); \
81 } while (0)
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82
83#define ceph_decode_copy_safe(p, end, pv, n, bad) \
84 do { \
85 ceph_decode_need(p, end, n, bad); \
86 ceph_decode_copy(p, pv, n); \
87 } while (0)
88
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89/*
90 * Allocate a buffer big enough to hold the wire-encoded string, and
91 * decode the string into it. The resulting string will always be
92 * terminated with '\0'. If successful, *p will be advanced
93 * past the decoded data. Also, if lenp is not a null pointer, the
94 * length (not including the terminating '\0') will be recorded in
95 * *lenp. Note that a zero-length string is a valid return value.
96 *
97 * Returns a pointer to the newly-allocated string buffer, or a
98 * pointer-coded errno if an error occurs. Neither *p nor *lenp
99 * will have been updated if an error is returned.
100 *
101 * There are two possible failures:
102 * - converting the string would require accessing memory at or
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103 * beyond the "end" pointer provided (-ERANGE)
104 * - memory could not be allocated for the result (-ENOMEM)
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105 */
106static inline char *ceph_extract_encoded_string(void **p, void *end,
107 size_t *lenp, gfp_t gfp)
108{
109 u32 len;
110 void *sp = *p;
111 char *buf;
112
113 ceph_decode_32_safe(&sp, end, len, bad);
114 if (!ceph_has_room(&sp, end, len))
115 goto bad;
116
117 buf = kmalloc(len + 1, gfp);
118 if (!buf)
119 return ERR_PTR(-ENOMEM);
120
121 if (len)
122 memcpy(buf, sp, len);
123 buf[len] = '\0';
124
125 *p = (char *) *p + sizeof (u32) + len;
126 if (lenp)
127 *lenp = (size_t) len;
128
129 return buf;
130
131bad:
132 return ERR_PTR(-ERANGE);
133}
134
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135/*
136 * skip helpers
137 */
138#define ceph_decode_skip_n(p, end, n, bad) \
139 do { \
140 ceph_decode_need(p, end, n, bad); \
141 *p += n; \
142 } while (0)
143
144#define ceph_decode_skip_64(p, end, bad) \
145ceph_decode_skip_n(p, end, sizeof(u64), bad)
146
147#define ceph_decode_skip_32(p, end, bad) \
148ceph_decode_skip_n(p, end, sizeof(u32), bad)
149
150#define ceph_decode_skip_16(p, end, bad) \
151ceph_decode_skip_n(p, end, sizeof(u16), bad)
152
153#define ceph_decode_skip_8(p, end, bad) \
154ceph_decode_skip_n(p, end, sizeof(u8), bad)
155
156#define ceph_decode_skip_string(p, end, bad) \
157 do { \
158 u32 len; \
159 \
160 ceph_decode_32_safe(p, end, len, bad); \
161 ceph_decode_skip_n(p, end, len, bad); \
162 } while (0)
163
164#define ceph_decode_skip_set(p, end, type, bad) \
165 do { \
166 u32 len; \
167 \
168 ceph_decode_32_safe(p, end, len, bad); \
169 while (len--) \
170 ceph_decode_skip_##type(p, end, bad); \
171 } while (0)
172
173#define ceph_decode_skip_map(p, end, ktype, vtype, bad) \
174 do { \
175 u32 len; \
176 \
177 ceph_decode_32_safe(p, end, len, bad); \
178 while (len--) { \
179 ceph_decode_skip_##ktype(p, end, bad); \
180 ceph_decode_skip_##vtype(p, end, bad); \
181 } \
182 } while (0)
183
184#define ceph_decode_skip_map_of_map(p, end, ktype1, ktype2, vtype2, bad) \
185 do { \
186 u32 len; \
187 \
188 ceph_decode_32_safe(p, end, len, bad); \
189 while (len--) { \
190 ceph_decode_skip_##ktype1(p, end, bad); \
191 ceph_decode_skip_map(p, end, ktype2, vtype2, bad); \
192 } \
193 } while (0)
194
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195/*
196 * struct ceph_timespec <-> struct timespec
197 */
c89136ea 198static inline void ceph_decode_timespec(struct timespec *ts,
63f2d211 199 const struct ceph_timespec *tv)
c89136ea 200{
c3f56102
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201 ts->tv_sec = (__kernel_time_t)le32_to_cpu(tv->tv_sec);
202 ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
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203}
204static inline void ceph_encode_timespec(struct ceph_timespec *tv,
63f2d211 205 const struct timespec *ts)
c89136ea 206{
c3f56102
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207 tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
208 tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
c89136ea 209}
31b8006e 210
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211/*
212 * sockaddr_storage <-> ceph_sockaddr
213 */
214static inline void ceph_encode_addr(struct ceph_entity_addr *a)
215{
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216 __be16 ss_family = htons(a->in_addr.ss_family);
217 a->in_addr.ss_family = *(__u16 *)&ss_family;
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218}
219static inline void ceph_decode_addr(struct ceph_entity_addr *a)
220{
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221 __be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
222 a->in_addr.ss_family = ntohs(ss_family);
4e7a5dcd 223 WARN_ON(a->in_addr.ss_family == 512);
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224}
225
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226/*
227 * encoders
228 */
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229static inline void ceph_encode_64(void **p, u64 v)
230{
231 put_unaligned_le64(v, (__le64 *)*p);
232 *p += sizeof(u64);
233}
234static inline void ceph_encode_32(void **p, u32 v)
235{
236 put_unaligned_le32(v, (__le32 *)*p);
237 *p += sizeof(u32);
238}
239static inline void ceph_encode_16(void **p, u16 v)
240{
241 put_unaligned_le16(v, (__le16 *)*p);
242 *p += sizeof(u16);
243}
244static inline void ceph_encode_8(void **p, u8 v)
245{
246 *(u8 *)*p = v;
247 (*p)++;
248}
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249static inline void ceph_encode_copy(void **p, const void *s, int len)
250{
251 memcpy(*p, s, len);
252 *p += len;
253}
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254
255/*
256 * filepath, string encoders
257 */
258static inline void ceph_encode_filepath(void **p, void *end,
259 u64 ino, const char *path)
260{
261 u32 len = path ? strlen(path) : 0;
c61a1abd 262 BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
ac8839d7 263 ceph_encode_8(p, 1);
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264 ceph_encode_64(p, ino);
265 ceph_encode_32(p, len);
266 if (len)
267 memcpy(*p, path, len);
268 *p += len;
269}
270
271static inline void ceph_encode_string(void **p, void *end,
272 const char *s, u32 len)
273{
274 BUG_ON(*p + sizeof(len) + len > end);
275 ceph_encode_32(p, len);
276 if (len)
277 memcpy(*p, s, len);
278 *p += len;
279}
280
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281/*
282 * version and length starting block encoders/decoders
283 */
284
285/* current code version (u8) + compat code version (u8) + len of struct (u32) */
286#define CEPH_ENCODING_START_BLK_LEN 6
287
288/**
289 * ceph_start_encoding - start encoding block
290 * @struct_v: current (code) version of the encoding
291 * @struct_compat: oldest code version that can decode it
292 * @struct_len: length of struct encoding
293 */
294static inline void ceph_start_encoding(void **p, u8 struct_v, u8 struct_compat,
295 u32 struct_len)
296{
297 ceph_encode_8(p, struct_v);
298 ceph_encode_8(p, struct_compat);
299 ceph_encode_32(p, struct_len);
300}
301
302/**
303 * ceph_start_decoding - start decoding block
304 * @v: current version of the encoding that the code supports
305 * @name: name of the struct (free-form)
306 * @struct_v: out param for the encoding version
307 * @struct_len: out param for the length of struct encoding
308 *
309 * Validates the length of struct encoding, so unsafe ceph_decode_*
310 * variants can be used for decoding.
311 */
312static inline int ceph_start_decoding(void **p, void *end, u8 v,
313 const char *name, u8 *struct_v,
314 u32 *struct_len)
315{
316 u8 struct_compat;
317
318 ceph_decode_need(p, end, CEPH_ENCODING_START_BLK_LEN, bad);
319 *struct_v = ceph_decode_8(p);
320 struct_compat = ceph_decode_8(p);
321 if (v < struct_compat) {
322 pr_warn("got struct_v %d struct_compat %d > %d of %s\n",
323 *struct_v, struct_compat, v, name);
324 return -EINVAL;
325 }
326
327 *struct_len = ceph_decode_32(p);
328 ceph_decode_need(p, end, *struct_len, bad);
329 return 0;
330
331bad:
332 return -ERANGE;
333}
334
dd5f049d
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335#define ceph_encode_need(p, end, n, bad) \
336 do { \
337 if (!likely(ceph_has_room(p, end, n))) \
338 goto bad; \
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339 } while (0)
340
341#define ceph_encode_64_safe(p, end, v, bad) \
342 do { \
343 ceph_encode_need(p, end, sizeof(u64), bad); \
344 ceph_encode_64(p, v); \
345 } while (0)
346#define ceph_encode_32_safe(p, end, v, bad) \
347 do { \
348 ceph_encode_need(p, end, sizeof(u32), bad); \
dd5f049d 349 ceph_encode_32(p, v); \
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350 } while (0)
351#define ceph_encode_16_safe(p, end, v, bad) \
352 do { \
353 ceph_encode_need(p, end, sizeof(u16), bad); \
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354 ceph_encode_16(p, v); \
355 } while (0)
356#define ceph_encode_8_safe(p, end, v, bad) \
357 do { \
358 ceph_encode_need(p, end, sizeof(u8), bad); \
359 ceph_encode_8(p, v); \
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360 } while (0)
361
362#define ceph_encode_copy_safe(p, end, pv, n, bad) \
363 do { \
364 ceph_encode_need(p, end, n, bad); \
365 ceph_encode_copy(p, pv, n); \
366 } while (0)
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367#define ceph_encode_string_safe(p, end, s, n, bad) \
368 do { \
369 ceph_encode_need(p, end, n, bad); \
370 ceph_encode_string(p, end, s, n); \
371 } while (0)
c7e337d6 372
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373
374#endif