xref: /openbmc/linux/include/linux/ceph/decode.h (revision cd1a677c)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __CEPH_DECODE_H
3 #define __CEPH_DECODE_H
4 
5 #include <linux/err.h>
6 #include <linux/bug.h>
7 #include <linux/slab.h>
8 #include <linux/time.h>
9 #include <asm/unaligned.h>
10 
11 #include <linux/ceph/types.h>
12 
13 /*
14  * in all cases,
15  *   void **p     pointer to position pointer
16  *   void *end    pointer to end of buffer (last byte + 1)
17  */
18 
ceph_decode_64(void ** p)19 static inline u64 ceph_decode_64(void **p)
20 {
21 	u64 v = get_unaligned_le64(*p);
22 	*p += sizeof(u64);
23 	return v;
24 }
ceph_decode_32(void ** p)25 static inline u32 ceph_decode_32(void **p)
26 {
27 	u32 v = get_unaligned_le32(*p);
28 	*p += sizeof(u32);
29 	return v;
30 }
ceph_decode_16(void ** p)31 static inline u16 ceph_decode_16(void **p)
32 {
33 	u16 v = get_unaligned_le16(*p);
34 	*p += sizeof(u16);
35 	return v;
36 }
ceph_decode_8(void ** p)37 static inline u8 ceph_decode_8(void **p)
38 {
39 	u8 v = *(u8 *)*p;
40 	(*p)++;
41 	return v;
42 }
ceph_decode_copy(void ** p,void * pv,size_t n)43 static inline void ceph_decode_copy(void **p, void *pv, size_t n)
44 {
45 	memcpy(pv, *p, n);
46 	*p += n;
47 }
48 
49 /*
50  * bounds check input.
51  */
ceph_has_room(void ** p,void * end,size_t n)52 static inline bool ceph_has_room(void **p, void *end, size_t n)
53 {
54 	return end >= *p && n <= end - *p;
55 }
56 
57 #define ceph_decode_need(p, end, n, bad)			\
58 	do {							\
59 		if (!likely(ceph_has_room(p, end, n)))		\
60 			goto bad;				\
61 	} while (0)
62 
63 #define ceph_decode_64_safe(p, end, v, bad)			\
64 	do {							\
65 		ceph_decode_need(p, end, sizeof(u64), bad);	\
66 		v = ceph_decode_64(p);				\
67 	} while (0)
68 #define ceph_decode_32_safe(p, end, v, bad)			\
69 	do {							\
70 		ceph_decode_need(p, end, sizeof(u32), bad);	\
71 		v = ceph_decode_32(p);				\
72 	} while (0)
73 #define ceph_decode_16_safe(p, end, v, bad)			\
74 	do {							\
75 		ceph_decode_need(p, end, sizeof(u16), bad);	\
76 		v = ceph_decode_16(p);				\
77 	} while (0)
78 #define ceph_decode_8_safe(p, end, v, bad)			\
79 	do {							\
80 		ceph_decode_need(p, end, sizeof(u8), bad);	\
81 		v = ceph_decode_8(p);				\
82 	} while (0)
83 
84 #define ceph_decode_copy_safe(p, end, pv, n, bad)		\
85 	do {							\
86 		ceph_decode_need(p, end, n, bad);		\
87 		ceph_decode_copy(p, pv, n);			\
88 	} while (0)
89 
90 /*
91  * Allocate a buffer big enough to hold the wire-encoded string, and
92  * decode the string into it.  The resulting string will always be
93  * terminated with '\0'.  If successful, *p will be advanced
94  * past the decoded data.  Also, if lenp is not a null pointer, the
95  * length (not including the terminating '\0') will be recorded in
96  * *lenp.  Note that a zero-length string is a valid return value.
97  *
98  * Returns a pointer to the newly-allocated string buffer, or a
99  * pointer-coded errno if an error occurs.  Neither *p nor *lenp
100  * will have been updated if an error is returned.
101  *
102  * There are two possible failures:
103  *   - converting the string would require accessing memory at or
104  *     beyond the "end" pointer provided (-ERANGE)
105  *   - memory could not be allocated for the result (-ENOMEM)
106  */
ceph_extract_encoded_string(void ** p,void * end,size_t * lenp,gfp_t gfp)107 static inline char *ceph_extract_encoded_string(void **p, void *end,
108 						size_t *lenp, gfp_t gfp)
109 {
110 	u32 len;
111 	void *sp = *p;
112 	char *buf;
113 
114 	ceph_decode_32_safe(&sp, end, len, bad);
115 	if (!ceph_has_room(&sp, end, len))
116 		goto bad;
117 
118 	buf = kmalloc(len + 1, gfp);
119 	if (!buf)
120 		return ERR_PTR(-ENOMEM);
121 
122 	if (len)
123 		memcpy(buf, sp, len);
124 	buf[len] = '\0';
125 
126 	*p = (char *) *p + sizeof (u32) + len;
127 	if (lenp)
128 		*lenp = (size_t) len;
129 
130 	return buf;
131 
132 bad:
133 	return ERR_PTR(-ERANGE);
134 }
135 
136 /*
137  * skip helpers
138  */
139 #define ceph_decode_skip_n(p, end, n, bad)			\
140 	do {							\
141 		ceph_decode_need(p, end, n, bad);		\
142                 *p += n;					\
143 	} while (0)
144 
145 #define ceph_decode_skip_64(p, end, bad)			\
146 ceph_decode_skip_n(p, end, sizeof(u64), bad)
147 
148 #define ceph_decode_skip_32(p, end, bad)			\
149 ceph_decode_skip_n(p, end, sizeof(u32), bad)
150 
151 #define ceph_decode_skip_16(p, end, bad)			\
152 ceph_decode_skip_n(p, end, sizeof(u16), bad)
153 
154 #define ceph_decode_skip_8(p, end, bad)				\
155 ceph_decode_skip_n(p, end, sizeof(u8), bad)
156 
157 #define ceph_decode_skip_string(p, end, bad)			\
158 	do {							\
159 		u32 len;					\
160 								\
161 		ceph_decode_32_safe(p, end, len, bad);		\
162 		ceph_decode_skip_n(p, end, len, bad);		\
163 	} while (0)
164 
165 #define ceph_decode_skip_set(p, end, type, bad)			\
166 	do {							\
167 		u32 len;					\
168 								\
169 		ceph_decode_32_safe(p, end, len, bad);		\
170 		while (len--)					\
171 			ceph_decode_skip_##type(p, end, bad);	\
172 	} while (0)
173 
174 #define ceph_decode_skip_map(p, end, ktype, vtype, bad)		\
175 	do {							\
176 		u32 len;					\
177 								\
178 		ceph_decode_32_safe(p, end, len, bad);		\
179 		while (len--) {					\
180 			ceph_decode_skip_##ktype(p, end, bad);	\
181 			ceph_decode_skip_##vtype(p, end, bad);	\
182 		}						\
183 	} while (0)
184 
185 #define ceph_decode_skip_map_of_map(p, end, ktype1, ktype2, vtype2, bad) \
186 	do {							\
187 		u32 len;					\
188 								\
189 		ceph_decode_32_safe(p, end, len, bad);		\
190 		while (len--) {					\
191 			ceph_decode_skip_##ktype1(p, end, bad);	\
192 			ceph_decode_skip_map(p, end, ktype2, vtype2, bad); \
193 		}						\
194 	} while (0)
195 
196 /*
197  * struct ceph_timespec <-> struct timespec64
198  */
ceph_decode_timespec64(struct timespec64 * ts,const struct ceph_timespec * tv)199 static inline void ceph_decode_timespec64(struct timespec64 *ts,
200 					  const struct ceph_timespec *tv)
201 {
202 	/*
203 	 * This will still overflow in year 2106.  We could extend
204 	 * the protocol to steal two more bits from tv_nsec to
205 	 * add three more 136 year epochs after that the way ext4
206 	 * does if necessary.
207 	 */
208 	ts->tv_sec = (time64_t)le32_to_cpu(tv->tv_sec);
209 	ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
210 }
ceph_encode_timespec64(struct ceph_timespec * tv,const struct timespec64 * ts)211 static inline void ceph_encode_timespec64(struct ceph_timespec *tv,
212 					  const struct timespec64 *ts)
213 {
214 	tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
215 	tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
216 }
217 
218 /*
219  * sockaddr_storage <-> ceph_sockaddr
220  */
221 #define CEPH_ENTITY_ADDR_TYPE_NONE	0
222 #define CEPH_ENTITY_ADDR_TYPE_LEGACY	__cpu_to_le32(1)
223 #define CEPH_ENTITY_ADDR_TYPE_MSGR2	__cpu_to_le32(2)
224 #define CEPH_ENTITY_ADDR_TYPE_ANY	__cpu_to_le32(3)
225 
ceph_encode_banner_addr(struct ceph_entity_addr * a)226 static inline void ceph_encode_banner_addr(struct ceph_entity_addr *a)
227 {
228 	__be16 ss_family = htons(a->in_addr.ss_family);
229 	a->in_addr.ss_family = *(__u16 *)&ss_family;
230 
231 	/* Banner addresses require TYPE_NONE */
232 	a->type = CEPH_ENTITY_ADDR_TYPE_NONE;
233 }
ceph_decode_banner_addr(struct ceph_entity_addr * a)234 static inline void ceph_decode_banner_addr(struct ceph_entity_addr *a)
235 {
236 	__be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
237 	a->in_addr.ss_family = ntohs(ss_family);
238 	WARN_ON(a->in_addr.ss_family == 512);
239 	a->type = CEPH_ENTITY_ADDR_TYPE_LEGACY;
240 }
241 
242 extern int ceph_decode_entity_addr(void **p, void *end,
243 				   struct ceph_entity_addr *addr);
244 int ceph_decode_entity_addrvec(void **p, void *end, bool msgr2,
245 			       struct ceph_entity_addr *addr);
246 
247 int ceph_entity_addr_encoding_len(const struct ceph_entity_addr *addr);
248 void ceph_encode_entity_addr(void **p, const struct ceph_entity_addr *addr);
249 
250 /*
251  * encoders
252  */
ceph_encode_64(void ** p,u64 v)253 static inline void ceph_encode_64(void **p, u64 v)
254 {
255 	put_unaligned_le64(v, (__le64 *)*p);
256 	*p += sizeof(u64);
257 }
ceph_encode_32(void ** p,u32 v)258 static inline void ceph_encode_32(void **p, u32 v)
259 {
260 	put_unaligned_le32(v, (__le32 *)*p);
261 	*p += sizeof(u32);
262 }
ceph_encode_16(void ** p,u16 v)263 static inline void ceph_encode_16(void **p, u16 v)
264 {
265 	put_unaligned_le16(v, (__le16 *)*p);
266 	*p += sizeof(u16);
267 }
ceph_encode_8(void ** p,u8 v)268 static inline void ceph_encode_8(void **p, u8 v)
269 {
270 	*(u8 *)*p = v;
271 	(*p)++;
272 }
ceph_encode_copy(void ** p,const void * s,int len)273 static inline void ceph_encode_copy(void **p, const void *s, int len)
274 {
275 	memcpy(*p, s, len);
276 	*p += len;
277 }
278 
279 /*
280  * filepath, string encoders
281  */
ceph_encode_filepath(void ** p,void * end,u64 ino,const char * path)282 static inline void ceph_encode_filepath(void **p, void *end,
283 					u64 ino, const char *path)
284 {
285 	u32 len = path ? strlen(path) : 0;
286 	BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
287 	ceph_encode_8(p, 1);
288 	ceph_encode_64(p, ino);
289 	ceph_encode_32(p, len);
290 	if (len)
291 		memcpy(*p, path, len);
292 	*p += len;
293 }
294 
ceph_encode_string(void ** p,void * end,const char * s,u32 len)295 static inline void ceph_encode_string(void **p, void *end,
296 				      const char *s, u32 len)
297 {
298 	BUG_ON(*p + sizeof(len) + len > end);
299 	ceph_encode_32(p, len);
300 	if (len)
301 		memcpy(*p, s, len);
302 	*p += len;
303 }
304 
305 /*
306  * version and length starting block encoders/decoders
307  */
308 
309 /* current code version (u8) + compat code version (u8) + len of struct (u32) */
310 #define CEPH_ENCODING_START_BLK_LEN 6
311 
312 /**
313  * ceph_start_encoding - start encoding block
314  * @struct_v: current (code) version of the encoding
315  * @struct_compat: oldest code version that can decode it
316  * @struct_len: length of struct encoding
317  */
ceph_start_encoding(void ** p,u8 struct_v,u8 struct_compat,u32 struct_len)318 static inline void ceph_start_encoding(void **p, u8 struct_v, u8 struct_compat,
319 				       u32 struct_len)
320 {
321 	ceph_encode_8(p, struct_v);
322 	ceph_encode_8(p, struct_compat);
323 	ceph_encode_32(p, struct_len);
324 }
325 
326 /**
327  * ceph_start_decoding - start decoding block
328  * @v: current version of the encoding that the code supports
329  * @name: name of the struct (free-form)
330  * @struct_v: out param for the encoding version
331  * @struct_len: out param for the length of struct encoding
332  *
333  * Validates the length of struct encoding, so unsafe ceph_decode_*
334  * variants can be used for decoding.
335  */
ceph_start_decoding(void ** p,void * end,u8 v,const char * name,u8 * struct_v,u32 * struct_len)336 static inline int ceph_start_decoding(void **p, void *end, u8 v,
337 				      const char *name, u8 *struct_v,
338 				      u32 *struct_len)
339 {
340 	u8 struct_compat;
341 
342 	ceph_decode_need(p, end, CEPH_ENCODING_START_BLK_LEN, bad);
343 	*struct_v = ceph_decode_8(p);
344 	struct_compat = ceph_decode_8(p);
345 	if (v < struct_compat) {
346 		pr_warn("got struct_v %d struct_compat %d > %d of %s\n",
347 			*struct_v, struct_compat, v, name);
348 		return -EINVAL;
349 	}
350 
351 	*struct_len = ceph_decode_32(p);
352 	ceph_decode_need(p, end, *struct_len, bad);
353 	return 0;
354 
355 bad:
356 	return -ERANGE;
357 }
358 
359 #define ceph_encode_need(p, end, n, bad)			\
360 	do {							\
361 		if (!likely(ceph_has_room(p, end, n)))		\
362 			goto bad;				\
363 	} while (0)
364 
365 #define ceph_encode_64_safe(p, end, v, bad)			\
366 	do {							\
367 		ceph_encode_need(p, end, sizeof(u64), bad);	\
368 		ceph_encode_64(p, v);				\
369 	} while (0)
370 #define ceph_encode_32_safe(p, end, v, bad)			\
371 	do {							\
372 		ceph_encode_need(p, end, sizeof(u32), bad);	\
373 		ceph_encode_32(p, v);				\
374 	} while (0)
375 #define ceph_encode_16_safe(p, end, v, bad)			\
376 	do {							\
377 		ceph_encode_need(p, end, sizeof(u16), bad);	\
378 		ceph_encode_16(p, v);				\
379 	} while (0)
380 #define ceph_encode_8_safe(p, end, v, bad)			\
381 	do {							\
382 		ceph_encode_need(p, end, sizeof(u8), bad);	\
383 		ceph_encode_8(p, v);				\
384 	} while (0)
385 
386 #define ceph_encode_copy_safe(p, end, pv, n, bad)		\
387 	do {							\
388 		ceph_encode_need(p, end, n, bad);		\
389 		ceph_encode_copy(p, pv, n);			\
390 	} while (0)
391 #define ceph_encode_string_safe(p, end, s, n, bad)		\
392 	do {							\
393 		ceph_encode_need(p, end, n, bad);		\
394 		ceph_encode_string(p, end, s, n);		\
395 	} while (0)
396 
397 
398 #endif
399