decode.h

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#ifndef __CEPH_DECODE_H
#define __CEPH_DECODE_H

#include <linux/err.h>
#include <linux/bug.h>
#include <linux/time.h>
#include <asm/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 int 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 (-E
 *   - memory could not be allocated for the result
 */
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);
}

/*
 * struct ceph_timespec <-> struct timespec
 */
static inline void ceph_decode_timespec(struct timespec *ts,
                    const struct ceph_timespec *tv)
{
    ts->tv_sec = le32_to_cpu(tv->tv_sec);
    ts->tv_nsec = le32_to_cpu(tv->tv_nsec);
}
static inline void ceph_encode_timespec(struct ceph_timespec *tv,
                    const struct timespec *ts)
{
    tv->tv_sec = cpu_to_le32(ts->tv_sec);
    tv->tv_nsec = cpu_to_le32(ts->tv_nsec);
}

/*
 * sockaddr_storage <-> ceph_sockaddr
 */
static inline void ceph_encode_addr(struct ceph_entity_addr *a)
{
    __be16 ss_family = htons(a->in_addr.ss_family);
    a->in_addr.ss_family = *(__u16 *)&ss_family;
}
static inline void ceph_decode_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);
}

/*
 * 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;
}

#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_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