ceph/src/spdk/dpdk/lib/librte_eal/include/rte_random.h

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4
   5 #ifndef _RTE_RANDOM_H_
   6 #define _RTE_RANDOM_H_
   7
   8 /**
   9  * @file
  10  *
  11  * Pseudo-random Generators in RTE
  12  */
  13
  14 #ifdef __cplusplus
  15 extern "C" {
  16 #endif
  17
  18 #include <stdint.h>
  19
  20 #include <rte_compat.h>
  21
  22 /**
  23  * Seed the pseudo-random generator.
  24  *
  25  * The generator is automatically seeded by the EAL init with a timer
  26  * value. It may need to be re-seeded by the user with a real random
  27  * value.
  28  *
  29  * This function is not multi-thread safe in regards to other
  30  * rte_srand() calls, nor is it in relation to concurrent rte_rand()
  31  * calls.
  32  *
  33  * @param seedval
  34  *   The value of the seed.
  35  */
  36 void
  37 rte_srand(uint64_t seedval);
  38
  39 /**
  40  * Get a pseudo-random value.
  41  *
  42  * The generator is not cryptographically secure.
  43  *
  44  * If called from lcore threads, this function is thread-safe.
  45  *
  46  * @return
  47  *   A pseudo-random value between 0 and (1<<64)-1.
  48  */
  49 uint64_t
  50 rte_rand(void);
  51
  52 /**
  53  * Generates a pseudo-random number with an upper bound.
  54  *
  55  * This function returns an uniformly distributed (unbiased) random
  56  * number less than a user-specified maximum value.
  57  *
  58  * If called from lcore threads, this function is thread-safe.
  59  *
  60  * @param upper_bound
  61  *   The upper bound of the generated number.
  62  * @return
  63  *   A pseudo-random value between 0 and (upper_bound-1).
  64  */
  65 __rte_experimental
  66 uint64_t
  67 rte_rand_max(uint64_t upper_bound);
  68
  69 #ifdef __cplusplus
  70 }
  71 #endif
  72
  73
  74 #endif /* _RTE_RANDOM_H_ */