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netem: use a seeded PRNG for generating random losses

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Use prandom_u32_state() instead of get_random_u32() to generate
the random loss events of netem. The state of the prng is part
of the prng attribute of struct netem_sched_data.

Signed-off-by: François Michel <francois.michel@uclouvain.be>
Reviewed-by: Simon Horman <horms@kernel.org>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Link: https://lore.kernel.org/r/20230815092348.1449179-3-francois.michel@uclouvain.be
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
François Michel 2023-08-15 11:23:39 +02:00 committed by Jakub Kicinski
parent 4072d97ddc
commit 9c87b2aecc
1 changed files with 6 additions and 5 deletions
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11
net/sched/sch_netem.c
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@ -206,7 +206,7 @@ static u32 get_crandom(struct crndstate *state)
static bool loss_4state(struct netem_sched_data *q)
{
struct clgstate *clg = &q->clg;
u32 rnd = get_random_u32();
u32 rnd = prandom_u32_state(&q->prng.prng_state);
/*
* Makes a comparison between rnd and the transition
@ -271,18 +271,19 @@ static bool loss_4state(struct netem_sched_data *q)
static bool loss_gilb_ell(struct netem_sched_data *q)
{
struct clgstate *clg = &q->clg;
struct rnd_state *s = &q->prng.prng_state;
switch (clg->state) {
case GOOD_STATE:
if (get_random_u32() < clg->a1)
if (prandom_u32_state(s) < clg->a1)
clg->state = BAD_STATE;
if (get_random_u32() < clg->a4)
if (prandom_u32_state(s) < clg->a4)
return true;
break;
case BAD_STATE:
if (get_random_u32() < clg->a2)
if (prandom_u32_state(s) < clg->a2)
clg->state = GOOD_STATE;
if (get_random_u32() > clg->a3)
if (prandom_u32_state(s) > clg->a3)
return true;
}