src/lib/ctime/di_ops.h

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2021, The Tor Project, Inc. */
   4 /* See LICENSE for licensing information */
   5
   6 /**
   7  * \file di_ops.h
   8  * \brief Headers for di_ops.c
   9  **/
  10
  11 #ifndef TOR_DI_OPS_H
  12 #define TOR_DI_OPS_H
  13
  14 #include "orconfig.h"
  15 #include "lib/cc/torint.h"
  16
  17 int tor_memcmp(const void *a, const void *b, size_t sz);
  18 int tor_memeq(const void *a, const void *b, size_t sz);
  19 /** Perform a constant-time comparison of the <b>sz</b> bytes at <b>a</b> and
  20  * <b>b</b>, yielding true if they are different, and false otherwise. */
  21 #define tor_memneq(a,b,sz) (!tor_memeq((a),(b),(sz)))
  22
  23 /** Alias for the platform's memcmp() function.  This function is
  24  * <em>not</em> data-independent: we define this alias so that we can
  25  * mark cases where we are deliberately using a data-dependent memcmp()
  26  * implementation.
  27  */
  28 #define fast_memcmp(a,b,c) (memcmp((a),(b),(c)))
  29 /** Alias for the platform's memcmp() function, for use in testing equality.
  30  *
  31  * This function is <em>not</em> data-independent: we define this alias so
  32  * that we can mark cases where we are deliberately using a data-dependent
  33  * memcmp() implementation.
  34  */
  35 #define fast_memeq(a,b,c)  (0==memcmp((a),(b),(c)))
  36 /** Alias for the platform's memcmp() function, for use in testing inequality.
  37  *
  38  * This function is <em>not</em> data-independent: we define this alias so
  39  * that we can mark cases where we are deliberately using a data-dependent
  40  * memcmp() implementation.
  41  */
  42 #define fast_memneq(a,b,c) (0!=memcmp((a),(b),(c)))
  43
  44 int safe_mem_is_zero(const void *mem, size_t sz);
  45
  46 /** A type for a map from DIGEST256_LEN-byte blobs to void*, such that
  47  * data lookups take an amount of time proportional only to the size
  48  * of the map, and not to the position or presence of the item in the map.
  49  *
  50  * Not efficient for large maps! */
  51 typedef struct di_digest256_map_t di_digest256_map_t;
  52 /**
  53  * Type for a function used to free members of a di_digest256_map_t.
  54  **/
  55 typedef void (*dimap_free_fn)(void *);
  56
  57 void dimap_free_(di_digest256_map_t *map, dimap_free_fn free_fn);
  58 /**
  59  * @copydoc dimap_free_
  60  *
  61  * Additionally, set the pointer <b>map</b> to NULL.
  62  **/
  63 #define dimap_free(map, free_fn)                \
  64   do {                                          \
  65     dimap_free_((map), (free_fn));              \
  66     (map) = NULL;                               \
  67   } while (0)
  68 void dimap_add_entry(di_digest256_map_t **map,
  69                      const uint8_t *key, void *val);
  70 void *dimap_search(const di_digest256_map_t *map, const uint8_t *key,
  71                    void *dflt_val);
  72 int select_array_member_cumulative_timei(const uint64_t *entries,
  73                                          int n_entries,
  74                                          uint64_t total, uint64_t rand_val);
  75
  76 void memcpy_if_true_timei(bool s, void *dest, const void *src, size_t n);
  77
  78 #endif /* !defined(TOR_DI_OPS_H) */