include/linux/ceph/decode.h

   1 #ifndef __CEPH_DECODE_H
   2 #define __CEPH_DECODE_H
   3
   4 #include <linux/err.h>
   5 #include <linux/bug.h>
   6 #include <linux/slab.h>
   7 #include <linux/time.h>
   8 #include <asm/unaligned.h>
   9
  10 #include <linux/ceph/types.h>
  11
  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
  18 static inline u64 ceph_decode_64(void **p)
  19 {
  20         u64 v = get_unaligned_le64(*p);
  21         *p += sizeof(u64);
  22         return v;
  23 }
  24 static inline u32 ceph_decode_32(void **p)
  25 {
  26         u32 v = get_unaligned_le32(*p);
  27         *p += sizeof(u32);
  28         return v;
  29 }
  30 static inline u16 ceph_decode_16(void **p)
  31 {
  32         u16 v = get_unaligned_le16(*p);
  33         *p += sizeof(u16);
  34         return v;
  35 }
  36 static inline u8 ceph_decode_8(void **p)
  37 {
  38         u8 v = *(u8 *)*p;
  39         (*p)++;
  40         return v;
  41 }
  42 static inline void ceph_decode_copy(void **p, void *pv, size_t n)
  43 {
  44         memcpy(pv, *p, n);
  45         *p += n;
  46 }
  47
  48 /*
  49  * bounds check input.
  50  */
  51 static inline bool ceph_has_room(void **p, void *end, size_t n)
  52 {
  53         return end >= *p && n <= end - *p;
  54 }
  55
  56 #define ceph_decode_need(p, end, n, bad)                        \
  57         do {                                                    \
  58                 if (!likely(ceph_has_room(p, end, n)))          \
  59                         goto bad;                               \
  60         } while (0)
  61
  62 #define ceph_decode_64_safe(p, end, v, bad)                     \
  63         do {                                                    \
  64                 ceph_decode_need(p, end, sizeof(u64), bad);     \
  65                 v = ceph_decode_64(p);                          \
  66         } while (0)
  67 #define ceph_decode_32_safe(p, end, v, bad)                     \
  68         do {                                                    \
  69                 ceph_decode_need(p, end, sizeof(u32), bad);     \
  70                 v = ceph_decode_32(p);                          \
  71         } while (0)
  72 #define ceph_decode_16_safe(p, end, v, bad)                     \
  73         do {                                                    \
  74                 ceph_decode_need(p, end, sizeof(u16), bad);     \
  75                 v = ceph_decode_16(p);                          \
  76         } while (0)
  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)
  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
  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
 103  *     beyond the "end" pointer provided (-ERANGE)
 104  *   - memory could not be allocated for the result (-ENOMEM)
 105  */
 106 static 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
 131 bad:
 132         return ERR_PTR(-ERANGE);
 133 }
 134
 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)                        \
 145 ceph_decode_skip_n(p, end, sizeof(u64), bad)
 146
 147 #define ceph_decode_skip_32(p, end, bad)                        \
 148 ceph_decode_skip_n(p, end, sizeof(u32), bad)
 149
 150 #define ceph_decode_skip_16(p, end, bad)                        \
 151 ceph_decode_skip_n(p, end, sizeof(u16), bad)
 152
 153 #define ceph_decode_skip_8(p, end, bad)                         \
 154 ceph_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
 195 /*
 196  * struct ceph_timespec <-> struct timespec
 197  */
 198 static inline void ceph_decode_timespec(struct timespec *ts,
 199                                         const struct ceph_timespec *tv)
 200 {
 201         ts->tv_sec = (__kernel_time_t)le32_to_cpu(tv->tv_sec);
 202         ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
 203 }
 204 static inline void ceph_encode_timespec(struct ceph_timespec *tv,
 205                                         const struct timespec *ts)
 206 {
 207         tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
 208         tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
 209 }
 210
 211 /*
 212  * sockaddr_storage <-> ceph_sockaddr
 213  */
 214 static inline void ceph_encode_addr(struct ceph_entity_addr *a)
 215 {
 216         __be16 ss_family = htons(a->in_addr.ss_family);
 217         a->in_addr.ss_family = *(__u16 *)&ss_family;
 218 }
 219 static inline void ceph_decode_addr(struct ceph_entity_addr *a)
 220 {
 221         __be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
 222         a->in_addr.ss_family = ntohs(ss_family);
 223         WARN_ON(a->in_addr.ss_family == 512);
 224 }
 225
 226 /*
 227  * encoders
 228  */
 229 static inline void ceph_encode_64(void **p, u64 v)
 230 {
 231         put_unaligned_le64(v, (__le64 *)*p);
 232         *p += sizeof(u64);
 233 }
 234 static inline void ceph_encode_32(void **p, u32 v)
 235 {
 236         put_unaligned_le32(v, (__le32 *)*p);
 237         *p += sizeof(u32);
 238 }
 239 static inline void ceph_encode_16(void **p, u16 v)
 240 {
 241         put_unaligned_le16(v, (__le16 *)*p);
 242         *p += sizeof(u16);
 243 }
 244 static inline void ceph_encode_8(void **p, u8 v)
 245 {
 246         *(u8 *)*p = v;
 247         (*p)++;
 248 }
 249 static inline void ceph_encode_copy(void **p, const void *s, int len)
 250 {
 251         memcpy(*p, s, len);
 252         *p += len;
 253 }
 254
 255 /*
 256  * filepath, string encoders
 257  */
 258 static inline void ceph_encode_filepath(void **p, void *end,
 259                                         u64 ino, const char *path)
 260 {
 261         u32 len = path ? strlen(path) : 0;
 262         BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
 263         ceph_encode_8(p, 1);
 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
 271 static 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
 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  */
 294 static 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  */
 312 static 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
 331 bad:
 332         return -ERANGE;
 333 }
 334
 335 #define ceph_encode_need(p, end, n, bad)                        \
 336         do {                                                    \
 337                 if (!likely(ceph_has_room(p, end, n)))          \
 338                         goto bad;                               \
 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);     \
 349                 ceph_encode_32(p, v);                           \
 350         } while (0)
 351 #define ceph_encode_16_safe(p, end, v, bad)                     \
 352         do {                                                    \
 353                 ceph_encode_need(p, end, sizeof(u16), bad);     \
 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);                            \
 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)
 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)
 372
 373
 374 #endif