crypto_random.c File Reference

functions to gather random numbers More...

#include "platform.h"
#include "gnunet_util_lib.h"
#include <sodium.h>

Include dependency graph for crypto_random.c:

Go to the source code of this file.

Macros
#define	LOG(kind, ...)   GNUNET_log_from (kind, "util-crypto-random", __VA_ARGS__)
#define	LOG_STRERROR(kind, syscall)    GNUNET_log_from_strerror (kind, "util-crypto-random", syscall)
#define	RANDOM()   glibc_weak_rand32 ()
#define	SRANDOM(s)   glibc_weak_srand32 (s)
#define	RAND_MAX   0x7fffffff /* Hopefully this is correct */

Functions
void	glibc_weak_srand32 (int32_t s)
int32_t	glibc_weak_rand32 ()
void	GNUNET_CRYPTO_zero_keys (void *buffer, size_t length)
	Zero out buffer, securely against compiler optimizations.
void	GNUNET_CRYPTO_random_block (void *buffer, size_t length)
	Fill block with a random values.
uint32_t	GNUNET_CRYPTO_random_u32 (uint32_t max)
	Produce a random value.
unsigned int *	GNUNET_CRYPTO_random_permute (unsigned int n)
	Get an array with a random permutation of the numbers 0...n-1.
uint64_t	GNUNET_CRYPTO_random_u64 (uint64_t max)
	Generate a random unsigned 64-bit value.
void	GNUNET_CRYPTO_random_timeflake (struct GNUNET_Uuid *uuid)
	Fill UUID with a timeflake pseudo-random value.
void	GNUNET_CRYPTO_random_init (void)
void	__attribute__ ((constructor))
	Initialize sodium.

Variables
static int32_t	glibc_weak_rand32_state = 1

Detailed Description

functions to gather random numbers

Author

Christian Grothoff

Definition in file crypto_random.c.

Macro Definition Documentation

LOG

#define LOG	(		kind,
			...
	)		GNUNET_log_from (kind, "util-crypto-random", __VA_ARGS__)

Definition at line 32 of file crypto_random.c.

LOG_STRERROR

#define LOG_STRERROR	(		kind,
			syscall
	)		GNUNET_log_from_strerror (kind, "util-crypto-random", syscall)

Definition at line 34 of file crypto_random.c.

{
  glibc_weak_rand32_state = s;
}
 
 
int32_t
glibc_weak_rand32 ()
{
  int32_t val = glibc_weak_rand32_state;
 
  val = ((glibc_weak_rand32_state * 1103515245) + 12345) & 0x7fffffff;
  glibc_weak_rand32_state = val;
  return val;
}
 
 
#endif
 
 
void
GNUNET_CRYPTO_zero_keys (void *buffer, size_t length)
{
#if HAVE_MEMSET_S
  memset_s (buffer, length, 0, length);
#elif HAVE_EXPLICIT_BZERO
  explicit_bzero (buffer, length);
#else
  volatile unsigned char *p = buffer;
  while (length--)
    *p++ = 0;
#endif
}
 
 
void
GNUNET_CRYPTO_random_block (void *buffer,
                            size_t length)
{
  randombytes_buf (buffer,
                   length);
}
 
 
uint32_t
GNUNET_CRYPTO_random_u32 (uint32_t max)
{
  GNUNET_assert (max > 0);
 
  return randombytes_uniform (max);
}
 
 
unsigned int *
GNUNET_CRYPTO_random_permute (unsigned int n)
{
  unsigned int *ret;
  unsigned int i;
  unsigned int tmp;
  uint32_t x;
 
  GNUNET_assert (n > 0);
  ret = GNUNET_malloc (n * sizeof(unsigned int));
  for (i = 0; i < n; i++)
    ret[i] = i;
  for (i = n - 1; i > 0; i--)
  {
    x = GNUNET_CRYPTO_random_u32 (i + 1);
    tmp = ret[x];
    ret[x] = ret[i];
    ret[i] = tmp;
  }
  return ret;
}
 
 
uint64_t
GNUNET_CRYPTO_random_u64 (uint64_t max)
{
  uint64_t value;
  uint64_t threshold;
 
  GNUNET_assert (max > 0);
  /* randombytes_uniform() only supports 32-bit bounds.  Reject the
     incomplete residue range before reducing a full 64-bit value modulo
     max, so every possible result has the same probability. */
  /* threshold = 2^{64} \bmod max */
  threshold = (-max) % max;
  do
  {
    randombytes_buf (&value,
                     sizeof (value));
  }
  while (value < threshold);
  return value % max;
}
 
 
void
GNUNET_CRYPTO_random_timeflake (struct GNUNET_Uuid *uuid)
{
  struct GNUNET_TIME_Absolute now;
  uint64_t ms;
  uint64_t be;
  char *base;
 
  GNUNET_CRYPTO_random_block (uuid,
                              sizeof (struct GNUNET_Uuid));
  now = GNUNET_TIME_absolute_get ();
  ms = now.abs_value_us / GNUNET_TIME_UNIT_MILLISECONDS.rel_value_us;
  be = GNUNET_htonll (ms);
  base = (char *) &be;
  memcpy (uuid,
          base + 2,
          sizeof (be) - 2);
}
 
 
void
GNUNET_CRYPTO_random_init (void);
 
void __attribute__ ((constructor))
GNUNET_CRYPTO_random_init ()
{
  GNUNET_assert (-1 != sodium_init ());
}
 
 
/* end of crypto_random.c */

RANDOM

#define RANDOM

(

)

glibc_weak_rand32 ()

Definition at line 47 of file crypto_random.c.

SRANDOM

#define SRANDOM

(

s

)

glibc_weak_srand32 (s)

Definition at line 48 of file crypto_random.c.

RAND_MAX

#define RAND_MAX   0x7fffffff /* Hopefully this is correct */

Definition at line 52 of file crypto_random.c.

Function Documentation

glibc_weak_srand32()

void glibc_weak_srand32

(

int32_t

s

)

Definition at line 58 of file crypto_random.c.

{
  glibc_weak_rand32_state = s;
}

References glibc_weak_rand32_state.

glibc_weak_rand32()

int32_t glibc_weak_rand32

(

)

Definition at line 65 of file crypto_random.c.

{
  int32_t val = glibc_weak_rand32_state;
 
  val = ((glibc_weak_rand32_state * 1103515245) + 12345) & 0x7fffffff;
  glibc_weak_rand32_state = val;
  return val;
}

References glibc_weak_rand32_state.

GNUNET_CRYPTO_random_init()

void GNUNET_CRYPTO_random_init

(

void

)

__attribute__()

void __attribute__

(

(constructor)

)

Initialize sodium.

Definition at line 190 of file crypto_random.c.

{
  GNUNET_assert (-1 != sodium_init ());
}

References GNUNET_assert.

Variable Documentation

glibc_weak_rand32_state

int32_t glibc_weak_rand32_state = 1

static

Definition at line 54 of file crypto_random.c.

Referenced by glibc_weak_rand32(), and glibc_weak_srand32().