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netfilter: conntrack: use get_random_once for conntrack hash seed 

As earlier commit removed accessed to the hash from other files we can
also make it static.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2016-04-18 16:17:01 +02:00 committed by Pablo Neira Ayuso
parent 7001c6d109
commit 141658fb02
2 changed files with 3 additions and 25 deletions
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2
include/net/netfilter/nf_conntrack.h
View File

@ -289,8 +289,6 @@ struct kernel_param;
int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
extern unsigned int nf_conntrack_htable_size;
extern unsigned int nf_conntrack_max;
extern unsigned int nf_conntrack_hash_rnd;
void init_nf_conntrack_hash_rnd(void);
struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
const struct nf_conntrack_zone *zone,

26
net/netfilter/nf_conntrack_core.c
View File

@ -142,13 +142,14 @@ EXPORT_SYMBOL_GPL(nf_conntrack_max);
DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);
unsigned int nf_conntrack_hash_rnd __read_mostly;
EXPORT_SYMBOL_GPL(nf_conntrack_hash_rnd);
static unsigned int nf_conntrack_hash_rnd __read_mostly;
static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple)
{
unsigned int n;
get_random_once(&nf_conntrack_hash_rnd, sizeof(nf_conntrack_hash_rnd));
/* The direction must be ignored, so we hash everything up to the
* destination ports (which is a multiple of 4) and treat the last
* three bytes manually.
@ -815,21 +816,6 @@ restart:
return dropped;
}
void init_nf_conntrack_hash_rnd(void)
{
unsigned int rand;
/*
* Why not initialize nf_conntrack_rnd in a "init()" function ?
* Because there isn't enough entropy when system initializing,
* and we initialize it as late as possible.
*/
do {
get_random_bytes(&rand, sizeof(rand));
} while (!rand);
cmpxchg(&nf_conntrack_hash_rnd, 0, rand);
}
static struct nf_conn *
__nf_conntrack_alloc(struct net *net,
const struct nf_conntrack_zone *zone,
@ -839,12 +825,6 @@ __nf_conntrack_alloc(struct net *net,
{
struct nf_conn *ct;
if (unlikely(!nf_conntrack_hash_rnd)) {
init_nf_conntrack_hash_rnd();
/* recompute the hash as nf_conntrack_hash_rnd is initialized */
hash = hash_conntrack_raw(orig);
}
/* We don't want any race condition at early drop stage */
atomic_inc(&net->ct.count);