decode.h

  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 <linux/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
 19static inline u64 ceph_decode_64(void **p)
 20{
 21	u64 v = get_unaligned_le64(*p);
 22	*p += sizeof(u64);
 23	return v;
 24}
 25static inline u32 ceph_decode_32(void **p)
 26{
 27	u32 v = get_unaligned_le32(*p);
 28	*p += sizeof(u32);
 29	return v;
 30}
 31static inline u16 ceph_decode_16(void **p)
 32{
 33	u16 v = get_unaligned_le16(*p);
 34	*p += sizeof(u16);
 35	return v;
 36}
 37static inline u8 ceph_decode_8(void **p)
 38{
 39	u8 v = *(u8 *)*p;
 40	(*p)++;
 41	return v;
 42}
 43static 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 */
 52static 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 */
107static 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
132bad:
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)			\
146ceph_decode_skip_n(p, end, sizeof(u64), bad)
147
148#define ceph_decode_skip_32(p, end, bad)			\
149ceph_decode_skip_n(p, end, sizeof(u32), bad)
150
151#define ceph_decode_skip_16(p, end, bad)			\
152ceph_decode_skip_n(p, end, sizeof(u16), bad)
153
154#define ceph_decode_skip_8(p, end, bad)				\
155ceph_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 */
199static 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}
211static 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
226static 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}
234static 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
242extern int ceph_decode_entity_addr(void **p, void *end,
243				   struct ceph_entity_addr *addr);
244int ceph_decode_entity_addrvec(void **p, void *end, bool msgr2,
245			       struct ceph_entity_addr *addr);
246
247int ceph_entity_addr_encoding_len(const struct ceph_entity_addr *addr);
248void ceph_encode_entity_addr(void **p, const struct ceph_entity_addr *addr);
249
250/*
251 * encoders
252 */
253static inline void ceph_encode_64(void **p, u64 v)
254{
255	put_unaligned_le64(v, (__le64 *)*p);
256	*p += sizeof(u64);
257}
258static inline void ceph_encode_32(void **p, u32 v)
259{
260	put_unaligned_le32(v, (__le32 *)*p);
261	*p += sizeof(u32);
262}
263static inline void ceph_encode_16(void **p, u16 v)
264{
265	put_unaligned_le16(v, (__le16 *)*p);
266	*p += sizeof(u16);
267}
268static inline void ceph_encode_8(void **p, u8 v)
269{
270	*(u8 *)*p = v;
271	(*p)++;
272}
273static 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 */
282static 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
295static 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 */
318static 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 */
336static 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
355bad:
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