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  * struct ceph_timespec <-> struct timespec
 137  */
 138 static inline void ceph_decode_timespec(struct timespec *ts,
 139                                         const struct ceph_timespec *tv)
 140 {
 141         ts->tv_sec = (__kernel_time_t)le32_to_cpu(tv->tv_sec);
 142         ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
 143 }
 144 static inline void ceph_encode_timespec(struct ceph_timespec *tv,
 145                                         const struct timespec *ts)
 146 {
 147         tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
 148         tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
 149 }
 150
 151 /*
 152  * sockaddr_storage <-> ceph_sockaddr
 153  */
 154 static inline void ceph_encode_addr(struct ceph_entity_addr *a)
 155 {
 156         __be16 ss_family = htons(a->in_addr.ss_family);
 157         a->in_addr.ss_family = *(__u16 *)&ss_family;
 158 }
 159 static inline void ceph_decode_addr(struct ceph_entity_addr *a)
 160 {
 161         __be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
 162         a->in_addr.ss_family = ntohs(ss_family);
 163         WARN_ON(a->in_addr.ss_family == 512);
 164 }
 165
 166 /*
 167  * encoders
 168  */
 169 static inline void ceph_encode_64(void **p, u64 v)
 170 {
 171         put_unaligned_le64(v, (__le64 *)*p);
 172         *p += sizeof(u64);
 173 }
 174 static inline void ceph_encode_32(void **p, u32 v)
 175 {
 176         put_unaligned_le32(v, (__le32 *)*p);
 177         *p += sizeof(u32);
 178 }
 179 static inline void ceph_encode_16(void **p, u16 v)
 180 {
 181         put_unaligned_le16(v, (__le16 *)*p);
 182         *p += sizeof(u16);
 183 }
 184 static inline void ceph_encode_8(void **p, u8 v)
 185 {
 186         *(u8 *)*p = v;
 187         (*p)++;
 188 }
 189 static inline void ceph_encode_copy(void **p, const void *s, int len)
 190 {
 191         memcpy(*p, s, len);
 192         *p += len;
 193 }
 194
 195 /*
 196  * filepath, string encoders
 197  */
 198 static inline void ceph_encode_filepath(void **p, void *end,
 199                                         u64 ino, const char *path)
 200 {
 201         u32 len = path ? strlen(path) : 0;
 202         BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
 203         ceph_encode_8(p, 1);
 204         ceph_encode_64(p, ino);
 205         ceph_encode_32(p, len);
 206         if (len)
 207                 memcpy(*p, path, len);
 208         *p += len;
 209 }
 210
 211 static inline void ceph_encode_string(void **p, void *end,
 212                                       const char *s, u32 len)
 213 {
 214         BUG_ON(*p + sizeof(len) + len > end);
 215         ceph_encode_32(p, len);
 216         if (len)
 217                 memcpy(*p, s, len);
 218         *p += len;
 219 }
 220
 221 /*
 222  * version and length starting block encoders/decoders
 223  */
 224
 225 /* current code version (u8) + compat code version (u8) + len of struct (u32) */
 226 #define CEPH_ENCODING_START_BLK_LEN 6
 227
 228 /**
 229  * ceph_start_encoding - start encoding block
 230  * @struct_v: current (code) version of the encoding
 231  * @struct_compat: oldest code version that can decode it
 232  * @struct_len: length of struct encoding
 233  */
 234 static inline void ceph_start_encoding(void **p, u8 struct_v, u8 struct_compat,
 235                                        u32 struct_len)
 236 {
 237         ceph_encode_8(p, struct_v);
 238         ceph_encode_8(p, struct_compat);
 239         ceph_encode_32(p, struct_len);
 240 }
 241
 242 /**
 243  * ceph_start_decoding - start decoding block
 244  * @v: current version of the encoding that the code supports
 245  * @name: name of the struct (free-form)
 246  * @struct_v: out param for the encoding version
 247  * @struct_len: out param for the length of struct encoding
 248  *
 249  * Validates the length of struct encoding, so unsafe ceph_decode_*
 250  * variants can be used for decoding.
 251  */
 252 static inline int ceph_start_decoding(void **p, void *end, u8 v,
 253                                       const char *name, u8 *struct_v,
 254                                       u32 *struct_len)
 255 {
 256         u8 struct_compat;
 257
 258         ceph_decode_need(p, end, CEPH_ENCODING_START_BLK_LEN, bad);
 259         *struct_v = ceph_decode_8(p);
 260         struct_compat = ceph_decode_8(p);
 261         if (v < struct_compat) {
 262                 pr_warn("got struct_v %d struct_compat %d > %d of %s\n",
 263                         *struct_v, struct_compat, v, name);
 264                 return -EINVAL;
 265         }
 266
 267         *struct_len = ceph_decode_32(p);
 268         ceph_decode_need(p, end, *struct_len, bad);
 269         return 0;
 270
 271 bad:
 272         return -ERANGE;
 273 }
 274
 275 #define ceph_encode_need(p, end, n, bad)                        \
 276         do {                                                    \
 277                 if (!likely(ceph_has_room(p, end, n)))          \
 278                         goto bad;                               \
 279         } while (0)
 280
 281 #define ceph_encode_64_safe(p, end, v, bad)                     \
 282         do {                                                    \
 283                 ceph_encode_need(p, end, sizeof(u64), bad);     \
 284                 ceph_encode_64(p, v);                           \
 285         } while (0)
 286 #define ceph_encode_32_safe(p, end, v, bad)                     \
 287         do {                                                    \
 288                 ceph_encode_need(p, end, sizeof(u32), bad);     \
 289                 ceph_encode_32(p, v);                           \
 290         } while (0)
 291 #define ceph_encode_16_safe(p, end, v, bad)                     \
 292         do {                                                    \
 293                 ceph_encode_need(p, end, sizeof(u16), bad);     \
 294                 ceph_encode_16(p, v);                           \
 295         } while (0)
 296 #define ceph_encode_8_safe(p, end, v, bad)                      \
 297         do {                                                    \
 298                 ceph_encode_need(p, end, sizeof(u8), bad);      \
 299                 ceph_encode_8(p, v);                            \
 300         } while (0)
 301
 302 #define ceph_encode_copy_safe(p, end, pv, n, bad)               \
 303         do {                                                    \
 304                 ceph_encode_need(p, end, n, bad);               \
 305                 ceph_encode_copy(p, pv, n);                     \
 306         } while (0)
 307 #define ceph_encode_string_safe(p, end, s, n, bad)              \
 308         do {                                                    \
 309                 ceph_encode_need(p, end, n, bad);               \
 310                 ceph_encode_string(p, end, s, n);               \
 311         } while (0)
 312
 313
 314 #endif