Quelle decode.h Sprache: C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __CEPH_DECODE_H
#define __CEPH_DECODE_H

#include <linux/err.h>
#include <linux/bug.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/unaligned.h>

#include <linux/ceph/types.h>

/*
* in all cases,
*   void **p     pointer to position pointer
*   void *end    pointer to end of buffer (last byte + 1)
*/

static inline u64 ceph_decode_64(void **p)
{
u64 v = get_unaligned_le64(*p);
*p += sizeof(u64);
return v;
}
static inline u32 ceph_decode_32(void **p)
{
u32 v = get_unaligned_le32(*p);
*p += sizeof(u32);
return v;
}
static inline u16 ceph_decode_16(void **p)
{
u16 v = get_unaligned_le16(*p);
*p += sizeof(u16);
return v;
}
static inline u8 ceph_decode_8(void **p)
{
u8 v = *(u8 *)*p;
(*p)++;
return v;
}
static inline void ceph_decode_copy(void **p, void *pv, size_t n)
{
memcpy(pv, *p, n);
*p += n;
}

/*
* bounds check input.
*/
static inline bool ceph_has_room(void **p, void *end, size_t n)
{
return end >= *p && n <= end - *p;
}

#define ceph_decode_need(p, end, n, bad)   \
do {       \
  if (!likely(ceph_has_room(p, end, n)))  \
   goto bad;    \
} while (0)

#define ceph_decode_64_safe(p, end, v, bad)   \
do {       \
  ceph_decode_need(p, end, sizeof(u64), bad); \
  v = ceph_decode_64(p);    \
} while (0)
#define ceph_decode_32_safe(p, end, v, bad)   \
do {       \
  ceph_decode_need(p, end, sizeof(u32), bad); \
  v = ceph_decode_32(p);    \
} while (0)
#define ceph_decode_16_safe(p, end, v, bad)   \
do {       \
  ceph_decode_need(p, end, sizeof(u16), bad); \
  v = ceph_decode_16(p);    \
} while (0)
#define ceph_decode_8_safe(p, end, v, bad)   \
do {       \
  ceph_decode_need(p, end, sizeof(u8), bad); \
  v = ceph_decode_8(p);    \
} while (0)

#define ceph_decode_copy_safe(p, end, pv, n, bad)  \
do {       \
  ceph_decode_need(p, end, n, bad);  \
  ceph_decode_copy(p, pv, n);   \
} while (0)

/*
* Allocate a buffer big enough to hold the wire-encoded string, and
* decode the string into it.  The resulting string will always be
* terminated with '\0'.  If successful, *p will be advanced
* past the decoded data.  Also, if lenp is not a null pointer, the
* length (not including the terminating '\0') will be recorded in
* *lenp.  Note that a zero-length string is a valid return value.
*
* Returns a pointer to the newly-allocated string buffer, or a
* pointer-coded errno if an error occurs.  Neither *p nor *lenp
* will have been updated if an error is returned.
*
* There are two possible failures:
*   - converting the string would require accessing memory at or
*     beyond the "end" pointer provided (-ERANGE)
*   - memory could not be allocated for the result (-ENOMEM)
*/
static inline char *ceph_extract_encoded_string(void **p, void *end,
      size_t *lenp, gfp_t gfp)
{
u32 len;
void *sp = *p;
char *buf;

ceph_decode_32_safe(&sp, end, len, bad);
if (!ceph_has_room(&sp, end, len))
  goto bad;

buf = kmalloc(len + 1, gfp);
if (!buf)
  return ERR_PTR(-ENOMEM);

if (len)
  memcpy(buf, sp, len);
buf[len] = '\0';

*p = (char *) *p + sizeof (u32) + len;
if (lenp)
  *lenp = (size_t) len;

return buf;

bad:
return ERR_PTR(-ERANGE);
}

/*
* skip helpers
*/
#define ceph_decode_skip_n(p, end, n, bad)   \
do {       \
  ceph_decode_need(p, end, n, bad);  \
                *p += n;     \
} while (0)

#define ceph_decode_skip_64(p, end, bad)   \
ceph_decode_skip_n(p, end, sizeof(u64), bad)

#define ceph_decode_skip_32(p, end, bad)   \
ceph_decode_skip_n(p, end, sizeof(u32), bad)

#define ceph_decode_skip_16(p, end, bad)   \
ceph_decode_skip_n(p, end, sizeof(u16), bad)

#define ceph_decode_skip_8(p, end, bad)    \
ceph_decode_skip_n(p, end, sizeof(u8), bad)

#define ceph_decode_skip_string(p, end, bad)   \
do {       \
  u32 len;     \
        \
  ceph_decode_32_safe(p, end, len, bad);  \
  ceph_decode_skip_n(p, end, len, bad);  \
} while (0)

#define ceph_decode_skip_set(p, end, type, bad)   \
do {       \
  u32 len;     \
        \
  ceph_decode_32_safe(p, end, len, bad);  \
  while (len--)     \
   ceph_decode_skip_##type(p, end, bad); \
} while (0)

#define ceph_decode_skip_map(p, end, ktype, vtype, bad)  \
do {       \
  u32 len;     \
        \
  ceph_decode_32_safe(p, end, len, bad);  \
  while (len--) {     \
   ceph_decode_skip_##ktype(p, end, bad); \
   ceph_decode_skip_##vtype(p, end, bad); \
  }      \
} while (0)

#define ceph_decode_skip_map_of_map(p, end, ktype1, ktype2, vtype2, bad) \
do {       \
  u32 len;     \
        \
  ceph_decode_32_safe(p, end, len, bad);  \
  while (len--) {     \
   ceph_decode_skip_##ktype1(p, end, bad); \
   ceph_decode_skip_map(p, end, ktype2, vtype2, bad); \
  }      \
} while (0)

/*
* struct ceph_timespec <-> struct timespec64
*/
static inline void ceph_decode_timespec64(struct timespec64 *ts,
       const struct ceph_timespec *tv)
{
/*
* This will still overflow in year 2106.  We could extend
* the protocol to steal two more bits from tv_nsec to
* add three more 136 year epochs after that the way ext4
* does if necessary.
*/
ts->tv_sec = (time64_t)le32_to_cpu(tv->tv_sec);
ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
}
static inline void ceph_encode_timespec64(struct ceph_timespec *tv,
       const struct timespec64 *ts)
{
tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
}

/*
* sockaddr_storage <-> ceph_sockaddr
*/
#define CEPH_ENTITY_ADDR_TYPE_NONE 0
#define CEPH_ENTITY_ADDR_TYPE_LEGACY __cpu_to_le32(1)
#define CEPH_ENTITY_ADDR_TYPE_MSGR2 __cpu_to_le32(2)
#define CEPH_ENTITY_ADDR_TYPE_ANY __cpu_to_le32(3)

static inline void ceph_encode_banner_addr(struct ceph_entity_addr *a)
{
__be16 ss_family = htons(a->in_addr.ss_family);
a->in_addr.ss_family = *(__u16 *)&ss_family;

/* Banner addresses require TYPE_NONE */
a->type = CEPH_ENTITY_ADDR_TYPE_NONE;
}
static inline void ceph_decode_banner_addr(struct ceph_entity_addr *a)
{
__be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
a->in_addr.ss_family = ntohs(ss_family);
WARN_ON(a->in_addr.ss_family == 512);
a->type = CEPH_ENTITY_ADDR_TYPE_LEGACY;
}

extern int ceph_decode_entity_addr(void **p, void *end,
       struct ceph_entity_addr *addr);
int ceph_decode_entity_addrvec(void **p, void *end, bool msgr2,
          struct ceph_entity_addr *addr);

int ceph_entity_addr_encoding_len(const struct ceph_entity_addr *addr);
void ceph_encode_entity_addr(void **p, const struct ceph_entity_addr *addr);

/*
* encoders
*/
static inline void ceph_encode_64(void **p, u64 v)
{
put_unaligned_le64(v, (__le64 *)*p);
*p += sizeof(u64);
}
static inline void ceph_encode_32(void **p, u32 v)
{
put_unaligned_le32(v, (__le32 *)*p);
*p += sizeof(u32);
}
static inline void ceph_encode_16(void **p, u16 v)
{
put_unaligned_le16(v, (__le16 *)*p);
*p += sizeof(u16);
}
static inline void ceph_encode_8(void **p, u8 v)
{
*(u8 *)*p = v;
(*p)++;
}
static inline void ceph_encode_copy(void **p, const void *s, int len)
{
memcpy(*p, s, len);
*p += len;
}

/*
* filepath, string encoders
*/
static inline void ceph_encode_filepath(void **p, void *end,
     u64 ino, const char *path)
{
u32 len = path ? strlen(path) : 0;
BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
ceph_encode_8(p, 1);
ceph_encode_64(p, ino);
ceph_encode_32(p, len);
if (len)
  memcpy(*p, path, len);
*p += len;
}

static inline void ceph_encode_string(void **p, void *end,
          const char *s, u32 len)
{
BUG_ON(*p + sizeof(len) + len > end);
ceph_encode_32(p, len);
if (len)
  memcpy(*p, s, len);
*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)))  \
   goto bad;    \
} while (0)

#define ceph_encode_64_safe(p, end, v, bad)   \
do {       \
  ceph_encode_need(p, end, sizeof(u64), bad); \
  ceph_encode_64(p, v);    \
} while (0)
#define ceph_encode_32_safe(p, end, v, bad)   \
do {       \
  ceph_encode_need(p, end, sizeof(u32), bad); \
  ceph_encode_32(p, v);    \
} while (0)
#define ceph_encode_16_safe(p, end, v, bad)   \
do {       \
  ceph_encode_need(p, end, sizeof(u16), bad); \
  ceph_encode_16(p, v);    \
} while (0)
#define ceph_encode_8_safe(p, end, v, bad)   \
do {       \
  ceph_encode_need(p, end, sizeof(u8), bad); \
  ceph_encode_8(p, v);    \
} while (0)

#define ceph_encode_copy_safe(p, end, pv, n, bad)  \
do {       \
  ceph_encode_need(p, end, n, bad);  \
  ceph_encode_copy(p, pv, n);   \
} while (0)
#define ceph_encode_string_safe(p, end, s, n, bad)  \
do {       \
  ceph_encode_need(p, end, n, bad);  \
  ceph_encode_string(p, end, s, n);  \
} while (0)

#endif

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