Since nf_ct_expect_dst_hash() may be called without nf_conntrack_lock
locked, nf_ct_expect_hash_rnd should be initialized in the atomic way.
In this patch, we use nf_conntrack_hash_rnd instead of
nf_ct_expect_hash_rnd.
Signed-off-by: Changli Gao <xiaosuo@xxxxxxxxx>
---
v2: use nf_conntrack_hash_rnd.
include/net/netfilter/nf_conntrack.h | 2 ++
net/netfilter/nf_conntrack_core.c | 30 +++++++++++++++++-------------
net/netfilter/nf_conntrack_expect.c | 10 +++-------
3 files changed, 22 insertions(+), 20 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index caf17db..d85cff1 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -298,6 +298,8 @@ static inline int nf_ct_is_untracked(const struct nf_conn *ct)
extern 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);
#define NF_CT_STAT_INC(net, count) \
__this_cpu_inc((net)->ct.stat->count)
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 27a5ea6..e615119 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -65,7 +65,7 @@ EXPORT_SYMBOL_GPL(nf_conntrack_max);
DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);
-static unsigned int nf_conntrack_hash_rnd __read_mostly;
+unsigned int nf_conntrack_hash_rnd __read_mostly;
static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone)
{
@@ -596,6 +596,21 @@ static noinline int early_drop(struct net *net, unsigned int hash)
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, u16 zone,
const struct nf_conntrack_tuple *orig,
@@ -605,18 +620,7 @@ __nf_conntrack_alloc(struct net *net, u16 zone,
struct nf_conn *ct;
if (unlikely(!nf_conntrack_hash_rnd)) {
- 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);
-
+ init_nf_conntrack_hash_rnd();
/* recompute the hash as nf_conntrack_hash_rnd is initialized */
hash = hash_conntrack_raw(orig, zone);
}
diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c
index 46e8966..a20fb0b 100644
--- a/net/netfilter/nf_conntrack_expect.c
+++ b/net/netfilter/nf_conntrack_expect.c
@@ -32,9 +32,7 @@
unsigned int nf_ct_expect_hsize __read_mostly;
EXPORT_SYMBOL_GPL(nf_ct_expect_hsize);
-static unsigned int nf_ct_expect_hash_rnd __read_mostly;
unsigned int nf_ct_expect_max __read_mostly;
-static int nf_ct_expect_hash_rnd_initted __read_mostly;
static struct kmem_cache *nf_ct_expect_cachep __read_mostly;
@@ -77,15 +75,13 @@ static unsigned int nf_ct_expect_dst_hash(const struct nf_conntrack_tuple *tuple
{
unsigned int hash;
- if (unlikely(!nf_ct_expect_hash_rnd_initted)) {
- get_random_bytes(&nf_ct_expect_hash_rnd,
- sizeof(nf_ct_expect_hash_rnd));
- nf_ct_expect_hash_rnd_initted = 1;
+ if (unlikely(!nf_conntrack_hash_rnd)) {
+ init_nf_conntrack_hash_rnd();
}
hash = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all),
(((tuple->dst.protonum ^ tuple->src.l3num) << 16) |
- (__force __u16)tuple->dst.u.all) ^ nf_ct_expect_hash_rnd);
+ (__force __u16)tuple->dst.u.all) ^ nf_conntrack_hash_rnd);
return ((u64)hash * nf_ct_expect_hsize) >> 32;
}
--
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