diff options
Diffstat (limited to 'include/linux/ceph/decode.h')
| -rw-r--r-- | include/linux/ceph/decode.h | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/include/linux/ceph/decode.h b/include/linux/ceph/decode.h index 19e9932f3..f990f2cc9 100644 --- a/include/linux/ceph/decode.h +++ b/include/linux/ceph/decode.h @@ -3,6 +3,7 @@ #include <linux/err.h> #include <linux/bug.h> +#include <linux/slab.h> #include <linux/time.h> #include <asm/unaligned.h> @@ -217,6 +218,60 @@ static inline void ceph_encode_string(void **p, void *end, *p += len; } +/* + * version and length starting block encoders/decoders + */ + +/* current code version (u8) + compat code version (u8) + len of struct (u32) */ +#define CEPH_ENCODING_START_BLK_LEN 6 + +/** + * ceph_start_encoding - start encoding block + * @struct_v: current (code) version of the encoding + * @struct_compat: oldest code version that can decode it + * @struct_len: length of struct encoding + */ +static inline void ceph_start_encoding(void **p, u8 struct_v, u8 struct_compat, + u32 struct_len) +{ + ceph_encode_8(p, struct_v); + ceph_encode_8(p, struct_compat); + ceph_encode_32(p, struct_len); +} + +/** + * ceph_start_decoding - start decoding block + * @v: current version of the encoding that the code supports + * @name: name of the struct (free-form) + * @struct_v: out param for the encoding version + * @struct_len: out param for the length of struct encoding + * + * Validates the length of struct encoding, so unsafe ceph_decode_* + * variants can be used for decoding. + */ +static inline int ceph_start_decoding(void **p, void *end, u8 v, + const char *name, u8 *struct_v, + u32 *struct_len) +{ + u8 struct_compat; + + ceph_decode_need(p, end, CEPH_ENCODING_START_BLK_LEN, bad); + *struct_v = ceph_decode_8(p); + struct_compat = ceph_decode_8(p); + if (v < struct_compat) { + pr_warn("got struct_v %d struct_compat %d > %d of %s\n", + *struct_v, struct_compat, v, name); + return -EINVAL; + } + + *struct_len = ceph_decode_32(p); + ceph_decode_need(p, end, *struct_len, bad); + return 0; + +bad: + return -ERANGE; +} + #define ceph_encode_need(p, end, n, bad) \ do { \ if (!likely(ceph_has_room(p, end, n))) \ |