Commit 4072d97d authored by François Michel's avatar François Michel Committed by Jakub Kicinski
Browse files

netem: add prng attribute to netem_sched_data 



Add prng attribute to struct netem_sched_data and
allows setting the seed of the PRNG through netlink
using the new TCA_NETEM_PRNG_SEED attribute.
The PRNG attribute is not actually used yet.

Signed-off-by: default avatarFrançois Michel <francois.michel@uclouvain.be>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Acked-by: default avatarStephen Hemminger <stephen@networkplumber.org>
Link: https://lore.kernel.org/r/20230815092348.1449179-2-francois.michel@uclouvain.be


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a5e5b2cd

include/uapi/linux/pkt_sched.h

+1 −0
Original line number Diff line number Diff line
@@ -603,6 +603,7 @@ enum { 
	TCA_NETEM_JITTER64,

	TCA_NETEM_SLOT,

	TCA_NETEM_SLOT_DIST,

	TCA_NETEM_PRNG_SEED,

	__TCA_NETEM_MAX,

};

net/sched/sch_netem.c

+16 −0
Original line number Diff line number Diff line
@@ -105,6 +105,11 @@ struct netem_sched_data { 
		u32 rho;

	} delay_cor, loss_cor, dup_cor, reorder_cor, corrupt_cor;



	struct prng  {

		u64 seed;

		struct rnd_state prng_state;

	} prng;



	struct disttable *delay_dist;



	enum  {
@@ -922,6 +927,7 @@ static const struct nla_policy netem_policy[TCA_NETEM_MAX + 1] = { 
	[TCA_NETEM_LATENCY64]	= { .type = NLA_S64 },

	[TCA_NETEM_JITTER64]	= { .type = NLA_S64 },

	[TCA_NETEM_SLOT]	= { .len = sizeof(struct tc_netem_slot) },

	[TCA_NETEM_PRNG_SEED]	= { .type = NLA_U64 },

};



static int parse_attr(struct nlattr *tb[], int maxtype, struct nlattr *nla,
@@ -1040,6 +1046,12 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt, 
	/* capping jitter to the range acceptable by tabledist() */

	q->jitter = min_t(s64, abs(q->jitter), INT_MAX);



	if (tb[TCA_NETEM_PRNG_SEED])

		q->prng.seed = nla_get_u64(tb[TCA_NETEM_PRNG_SEED]);

	else

		q->prng.seed = get_random_u64();

	prandom_seed_state(&q->prng.prng_state, q->prng.seed);



unlock:

	sch_tree_unlock(sch);
@@ -1203,6 +1215,10 @@ static int netem_dump(struct Qdisc *sch, struct sk_buff *skb) 
			goto nla_put_failure;

	}



	if (nla_put_u64_64bit(skb, TCA_NETEM_PRNG_SEED, q->prng.seed,

			      TCA_NETEM_PAD))

		goto nla_put_failure;



	return nla_nest_end(skb, nla);



nla_put_failure: