unbound 0.1
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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 | MAX_VALUE 0x7fffffff |
Max random value. | |
#define | REKEY_BYTES (1 << 24) |
Number of bytes to reseed after. | |
Functions | |
void | ub_systemseed (unsigned int seed) |
Initialize the system randomness. | |
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. | |
long int | ub_random_max (struct ub_randstate *state, long int x) |
Generate random number between 0 and x-1. | |
void | ub_randfree (struct ub_randstate *s) |
Delete the random state. |
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. Here is their statement:
Copyright (c) 1996, David Mazieres <dm@uun.org> Copyright (c) 2008, Damien Miller <djm@openbsd.org>
Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#define MAX_VALUE 0x7fffffff |
Max random value.
Similar to RAND_MAX, but more portable (mingw uses only 15 bits random).
Referenced by ub_random(), and ub_random_max().
void ub_systemseed | ( | unsigned int | seed | ) |
Initialize the system randomness.
Obtains entropy from the system before a chroot or privilege makes it unavailable. You do not have to call this, otherwise ub_initstate does so.
seed,: | seed value to create state (if no good entropy is found). |
References log_err(), VERB_OPS, and verbose().
Referenced by daemon_init(), ub_arc4random_stir(), and ub_initstate().
struct ub_randstate* ub_initstate | ( | unsigned int | seed, |
struct ub_randstate * | from | ||
) | [read] |
Initialize a random generator state for use.
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. |
References log_err(), ub_arc4random_stir(), and ub_systemseed().
Referenced by daemon_create_workers(), libworker_setup(), rnd_test(), ub_ctx_create(), and worker_create().
long int ub_random | ( | struct ub_randstate * | state | ) |
Generate next random number from the state passed along.
Thread safe, so random numbers are repeatable.
state,: | must have been initialised with ub_initstate. |
References MAX_VALUE, ub_randstate::rc4, ub_randstate::rc4_ready, and ub_arc4random_stir().
Referenced by pending_tcp_query(), rnd_test(), select_id(), serviced_perturb_qname(), ub_arc4random_stir(), and ub_random_max().
long int ub_random_max | ( | struct ub_randstate * | state, |
long int | x | ||
) |
Generate random number between 0 and x-1.
No modulo bias.
state,: | must have been initialised with ub_initstate. |
x,: | an upper limit. not (negative or zero). must be smaller than 2**31. |
References MAX_VALUE, and ub_random().
Referenced by calc_next_probe(), daemon_get_shufport(), iter_ns_probability(), iter_server_selection(), pick_outgoing_tcp(), rnd_test(), and select_ifport().
void ub_randfree | ( | struct ub_randstate * | state | ) |
Delete the random state.
state,: | to delete. |
Referenced by daemon_delete(), libworker_delete(), rnd_test(), ub_ctx_create(), ub_ctx_delete(), and worker_delete().