random.c File Reference

Thread safe random functions. More...

#include "config.h"
#include "util/random.h"
#include "util/log.h"
#include <openssl/rand.h>
#include <openssl/rc4.h>
#include <openssl/err.h>

Data Structures
struct	ub_randstate
	Struct with per-thread random state. More...
Defines
#define	SEED_SIZE   20
	Size of key to use.
#define	REKEY_BYTES   (1 << 24)
	Number of bytes to reseed after.
Functions
static void	ub_arc4random_stir (struct ub_randstate *s, struct ub_randstate *from)
	reseed random generator
struct ub_randstate *	ub_initstate (unsigned int seed, struct ub_randstate *from)
	Initialize a random generator state for use.
long int	ub_random (struct ub_randstate *s)
	Generate next random number from the state passed along.
void	ub_randfree (struct ub_randstate *s)
	Delete the random state.

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Detailed Description

Thread safe random functions.

Similar to arc4random() with an explicit initialisation routine.

The code in this file is based on arc4random from openssh-4.0p1/openbsd-compat/bsd-arc4random.c That code is also BSD licensed.

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Function Documentation

struct ub_randstate* ub_initstate	(	unsigned int	seed,
		struct ub_randstate *	from
	)			[read]

Initialize a random generator state for use.

Parameters:

	seed,:	seed value to create state contents. (ignored for arc4random).
	from,:	if not NULL, the seed is taken from this random structure. can be used to seed random states via a parent-random-state that is itself seeded with entropy.

Returns:

new state or NULL alloc failure.

References log_err(), ub_arc4random_stir(), VERB_OPS, and verbose().

Referenced by daemon_create_workers(), libworker_setup(), rnd_test(), ub_ctx_create(), and worker_init().

long int ub_random

(

struct ub_randstate *

state

)

Generate next random number from the state passed along.

Thread safe, so random numbers are repeatable.

Parameters:

state,:

must have been initialised with ub_initstate.

Returns:

: random 31 bit value.

References ub_randstate::rc4, ub_randstate::rc4_ready, and ub_arc4random_stir().

Referenced by daemon_get_shufport(), iter_ns_probability(), iter_server_selection(), pending_tcp_query(), rnd_test(), select_id(), select_ifport(), serviced_perturb_qname(), and ub_arc4random_stir().

void ub_randfree

(

struct ub_randstate *

state

)

Delete the random state.

Parameters:

state,:

to delete.

Referenced by daemon_delete(), libworker_delete(), rnd_test(), ub_ctx_create(), ub_ctx_delete(), and worker_delete().