+++ /dev/null
-#include <linux/version.h>
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
-
-/*
- This is a maximally equidistributed combined Tausworthe generator
- based on code from GNU Scientific Library 1.5 (30 Jun 2004)
-
- x_n = (s1_n ^ s2_n ^ s3_n)
-
- s1_{n+1} = (((s1_n & 4294967294) <<12) ^ (((s1_n <<13) ^ s1_n) >>19))
- s2_{n+1} = (((s2_n & 4294967288) << 4) ^ (((s2_n << 2) ^ s2_n) >>25))
- s3_{n+1} = (((s3_n & 4294967280) <<17) ^ (((s3_n << 3) ^ s3_n) >>11))
-
- The period of this generator is about 2^88.
-
- From: P. L'Ecuyer, "Maximally Equidistributed Combined Tausworthe
- Generators", Mathematics of Computation, 65, 213 (1996), 203--213.
-
- This is available on the net from L'Ecuyer's home page,
-
- http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps
- ftp://ftp.iro.umontreal.ca/pub/simulation/lecuyer/papers/tausme.ps
-
- There is an erratum in the paper "Tables of Maximally
- Equidistributed Combined LFSR Generators", Mathematics of
- Computation, 68, 225 (1999), 261--269:
- http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps
-
- ... the k_j most significant bits of z_j must be non-
- zero, for each j. (Note: this restriction also applies to the
- computer code given in [4], but was mistakenly not mentioned in
- that paper.)
-
- This affects the seeding procedure by imposing the requirement
- s1 > 1, s2 > 7, s3 > 15.
-
-*/
-
-#include <linux/types.h>
-#include <linux/module.h>
-#include <linux/jiffies.h>
-#include <linux/random.h>
-#include <linux/smp.h>
-
-#include "compat26.h"
-
-struct rnd_state {
- u32 s1, s2, s3;
-};
-
-static struct rnd_state net_rand_state[NR_CPUS];
-
-static u32 __random32(struct rnd_state *state)
-{
-#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
-
- state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);
- state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);
- state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17);
-
- return (state->s1 ^ state->s2 ^ state->s3);
-}
-
-static void __set_random32(struct rnd_state *state, unsigned long s)
-{
- if (s == 0)
- s = 1; /* default seed is 1 */
-
-#define LCG(n) (69069 * n)
- state->s1 = LCG(s);
- state->s2 = LCG(state->s1);
- state->s3 = LCG(state->s2);
-
- /* "warm it up" */
- __random32(state);
- __random32(state);
- __random32(state);
- __random32(state);
- __random32(state);
- __random32(state);
-}
-
-/**
- * random32 - pseudo random number generator
- *
- * A 32 bit pseudo-random number is generated using a fast
- * algorithm suitable for simulation. This algorithm is NOT
- * considered safe for cryptographic use.
- */
-u32 random32(void)
-{
- return __random32(&net_rand_state[smp_processor_id()]);
-}
-
-/**
- * srandom32 - add entropy to pseudo random number generator
- * @seed: seed value
- *
- * Add some additional seeding to the random32() pool.
- * Note: this pool is per cpu so it only affects current CPU.
- */
-void srandom32(u32 entropy)
-{
- struct rnd_state *state = &net_rand_state[smp_processor_id()];
- __set_random32(state, state->s1 ^ entropy);
-}
-
-static int __init random32_reseed(void);
-
-/*
- * Generate some initially weak seeding values to allow
- * to start the random32() engine.
- */
-int __init random32_init(void)
-{
- int i;
-
- for (i = 0; i < NR_CPUS; i++) {
- struct rnd_state *state = &net_rand_state[i];
- __set_random32(state, i + jiffies);
- }
- random32_reseed();
- return 0;
-}
-
-/*
- * Generate better values after random number generator
- * is fully initalized.
- */
-static int __init random32_reseed(void)
-{
- int i;
- unsigned long seed;
-
- for (i = 0; i < NR_CPUS; i++) {
- struct rnd_state *state = &net_rand_state[i];
-
- get_random_bytes(&seed, sizeof(seed));
- __set_random32(state, seed);
- }
- return 0;
-}
-
-#endif /* kernel < 2.6.19 */
projects / openvswitch / commitdiff