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/time.h>
   7 #include <asm/unaligned.h>
   8
   9 #include <linux/ceph/types.h>
  10
  11 /* This seemed to be the easiest place to define these */
  12
  13 #define U8_MAX  ((u8)(~0U))
  14 #define U16_MAX ((u16)(~0U))
  15 #define U32_MAX ((u32)(~0U))
  16 #define U64_MAX ((u64)(~0ULL))
  17
  18 #define S8_MAX  ((s8)(U8_MAX >> 1))
  19 #define S16_MAX ((s16)(U16_MAX >> 1))
  20 #define S32_MAX ((s32)(U32_MAX >> 1))
  21 #define S64_MAX ((s64)(U64_MAX >> 1LL))
  22
  23 #define S8_MIN  ((s8)(-S8_MAX - 1))
  24 #define S16_MIN ((s16)(-S16_MAX - 1))
  25 #define S32_MIN ((s32)(-S32_MAX - 1))
  26 #define S64_MIN ((s64)(-S64_MAX - 1LL))
  27
  28 /*
  29  * in all cases,
  30  *   void **p     pointer to position pointer
  31  *   void *end    pointer to end of buffer (last byte + 1)
  32  */
  33
  34 static inline u64 ceph_decode_64(void **p)
  35 {
  36         u64 v = get_unaligned_le64(*p);
  37         *p += sizeof(u64);
  38         return v;
  39 }
  40 static inline u32 ceph_decode_32(void **p)
  41 {
  42         u32 v = get_unaligned_le32(*p);
  43         *p += sizeof(u32);
  44         return v;
  45 }
  46 static inline u16 ceph_decode_16(void **p)
  47 {
  48         u16 v = get_unaligned_le16(*p);
  49         *p += sizeof(u16);
  50         return v;
  51 }
  52 static inline u8 ceph_decode_8(void **p)
  53 {
  54         u8 v = *(u8 *)*p;
  55         (*p)++;
  56         return v;
  57 }
  58 static inline void ceph_decode_copy(void **p, void *pv, size_t n)
  59 {
  60         memcpy(pv, *p, n);
  61         *p += n;
  62 }
  63
  64 /*
  65  * bounds check input.
  66  */
  67 static inline int ceph_has_room(void **p, void *end, size_t n)
  68 {
  69         return end >= *p && n <= end - *p;
  70 }
  71
  72 #define ceph_decode_need(p, end, n, bad)                        \
  73         do {                                                    \
  74                 if (!likely(ceph_has_room(p, end, n)))          \
  75                         goto bad;                               \
  76         } while (0)
  77
  78 #define ceph_decode_64_safe(p, end, v, bad)                     \
  79         do {                                                    \
  80                 ceph_decode_need(p, end, sizeof(u64), bad);     \
  81                 v = ceph_decode_64(p);                          \
  82         } while (0)
  83 #define ceph_decode_32_safe(p, end, v, bad)                     \
  84         do {                                                    \
  85                 ceph_decode_need(p, end, sizeof(u32), bad);     \
  86                 v = ceph_decode_32(p);                          \
  87         } while (0)
  88 #define ceph_decode_16_safe(p, end, v, bad)                     \
  89         do {                                                    \
  90                 ceph_decode_need(p, end, sizeof(u16), bad);     \
  91                 v = ceph_decode_16(p);                          \
  92         } while (0)
  93 #define ceph_decode_8_safe(p, end, v, bad)                      \
  94         do {                                                    \
  95                 ceph_decode_need(p, end, sizeof(u8), bad);      \
  96                 v = ceph_decode_8(p);                           \
  97         } while (0)
  98
  99 #define ceph_decode_copy_safe(p, end, pv, n, bad)               \
 100         do {                                                    \
 101                 ceph_decode_need(p, end, n, bad);               \
 102                 ceph_decode_copy(p, pv, n);                     \
 103         } while (0)
 104
 105 /*
 106  * Allocate a buffer big enough to hold the wire-encoded string, and
 107  * decode the string into it.  The resulting string will always be
 108  * terminated with '\0'.  If successful, *p will be advanced
 109  * past the decoded data.  Also, if lenp is not a null pointer, the
 110  * length (not including the terminating '\0') will be recorded in
 111  * *lenp.  Note that a zero-length string is a valid return value.
 112  *
 113  * Returns a pointer to the newly-allocated string buffer, or a
 114  * pointer-coded errno if an error occurs.  Neither *p nor *lenp
 115  * will have been updated if an error is returned.
 116  *
 117  * There are two possible failures:
 118  *   - converting the string would require accessing memory at or
 119  *     beyond the "end" pointer provided (-ERANGE)
 120  *   - memory could not be allocated for the result (-ENOMEM)
 121  */
 122 static inline char *ceph_extract_encoded_string(void **p, void *end,
 123                                                 size_t *lenp, gfp_t gfp)
 124 {
 125         u32 len;
 126         void *sp = *p;
 127         char *buf;
 128
 129         ceph_decode_32_safe(&sp, end, len, bad);
 130         if (!ceph_has_room(&sp, end, len))
 131                 goto bad;
 132
 133         buf = kmalloc(len + 1, gfp);
 134         if (!buf)
 135                 return ERR_PTR(-ENOMEM);
 136
 137         if (len)
 138                 memcpy(buf, sp, len);
 139         buf[len] = '\0';
 140
 141         *p = (char *) *p + sizeof (u32) + len;
 142         if (lenp)
 143                 *lenp = (size_t) len;
 144
 145         return buf;
 146
 147 bad:
 148         return ERR_PTR(-ERANGE);
 149 }
 150
 151 /*
 152  * struct ceph_timespec <-> struct timespec
 153  */
 154 static inline void ceph_decode_timespec(struct timespec *ts,
 155                                         const struct ceph_timespec *tv)
 156 {
 157         ts->tv_sec = (__kernel_time_t)le32_to_cpu(tv->tv_sec);
 158         ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
 159 }
 160 static inline void ceph_encode_timespec(struct ceph_timespec *tv,
 161                                         const struct timespec *ts)
 162 {
 163         BUG_ON(ts->tv_sec < 0);
 164         BUG_ON(ts->tv_sec > (__kernel_time_t)U32_MAX);
 165         BUG_ON(ts->tv_nsec < 0);
 166         BUG_ON(ts->tv_nsec > (long)U32_MAX);
 167
 168         tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
 169         tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
 170 }
 171
 172 /*
 173  * sockaddr_storage <-> ceph_sockaddr
 174  */
 175 static inline void ceph_encode_addr(struct ceph_entity_addr *a)
 176 {
 177         __be16 ss_family = htons(a->in_addr.ss_family);
 178         a->in_addr.ss_family = *(__u16 *)&ss_family;
 179 }
 180 static inline void ceph_decode_addr(struct ceph_entity_addr *a)
 181 {
 182         __be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
 183         a->in_addr.ss_family = ntohs(ss_family);
 184         WARN_ON(a->in_addr.ss_family == 512);
 185 }
 186
 187 /*
 188  * encoders
 189  */
 190 static inline void ceph_encode_64(void **p, u64 v)
 191 {
 192         put_unaligned_le64(v, (__le64 *)*p);
 193         *p += sizeof(u64);
 194 }
 195 static inline void ceph_encode_32(void **p, u32 v)
 196 {
 197         put_unaligned_le32(v, (__le32 *)*p);
 198         *p += sizeof(u32);
 199 }
 200 static inline void ceph_encode_16(void **p, u16 v)
 201 {
 202         put_unaligned_le16(v, (__le16 *)*p);
 203         *p += sizeof(u16);
 204 }
 205 static inline void ceph_encode_8(void **p, u8 v)
 206 {
 207         *(u8 *)*p = v;
 208         (*p)++;
 209 }
 210 static inline void ceph_encode_copy(void **p, const void *s, int len)
 211 {
 212         memcpy(*p, s, len);
 213         *p += len;
 214 }
 215
 216 /*
 217  * filepath, string encoders
 218  */
 219 static inline void ceph_encode_filepath(void **p, void *end,
 220                                         u64 ino, const char *path)
 221 {
 222         u32 len = path ? strlen(path) : 0;
 223         BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
 224         ceph_encode_8(p, 1);
 225         ceph_encode_64(p, ino);
 226         ceph_encode_32(p, len);
 227         if (len)
 228                 memcpy(*p, path, len);
 229         *p += len;
 230 }
 231
 232 static inline void ceph_encode_string(void **p, void *end,
 233                                       const char *s, u32 len)
 234 {
 235         BUG_ON(*p + sizeof(len) + len > end);
 236         ceph_encode_32(p, len);
 237         if (len)
 238                 memcpy(*p, s, len);
 239         *p += len;
 240 }
 241
 242 #define ceph_encode_need(p, end, n, bad)                        \
 243         do {                                                    \
 244                 if (!likely(ceph_has_room(p, end, n)))          \
 245                         goto bad;                               \
 246         } while (0)
 247
 248 #define ceph_encode_64_safe(p, end, v, bad)                     \
 249         do {                                                    \
 250                 ceph_encode_need(p, end, sizeof(u64), bad);     \
 251                 ceph_encode_64(p, v);                           \
 252         } while (0)
 253 #define ceph_encode_32_safe(p, end, v, bad)                     \
 254         do {                                                    \
 255                 ceph_encode_need(p, end, sizeof(u32), bad);     \
 256                 ceph_encode_32(p, v);                           \
 257         } while (0)
 258 #define ceph_encode_16_safe(p, end, v, bad)                     \
 259         do {                                                    \
 260                 ceph_encode_need(p, end, sizeof(u16), bad);     \
 261                 ceph_encode_16(p, v);                           \
 262         } while (0)
 263 #define ceph_encode_8_safe(p, end, v, bad)                      \
 264         do {                                                    \
 265                 ceph_encode_need(p, end, sizeof(u8), bad);      \
 266                 ceph_encode_8(p, v);                            \
 267         } while (0)
 268
 269 #define ceph_encode_copy_safe(p, end, pv, n, bad)               \
 270         do {                                                    \
 271                 ceph_encode_need(p, end, n, bad);               \
 272                 ceph_encode_copy(p, pv, n);                     \
 273         } while (0)
 274 #define ceph_encode_string_safe(p, end, s, n, bad)              \
 275         do {                                                    \
 276                 ceph_encode_need(p, end, n, bad);               \
 277                 ceph_encode_string(p, end, s, n);               \
 278         } while (0)
 279
 280
 281 #endif