Changes while reading through the netfilter code.
Added hint about how conntrack nf_conn refcnt is accessed.
And renamed repl_hash to reply_hash for readability
Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
---
include/net/netfilter/nf_conntrack.h | 8 +++++++-
net/netfilter/nf_conntrack_core.c | 20 ++++++++++----------
2 files changed, 17 insertions(+), 11 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index b2ac624..e10d1fa 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -73,7 +73,13 @@ struct nf_conn_help {
struct nf_conn {
/* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
- plus 1 for any connection(s) we are `master' for */
+ * plus 1 for any connection(s) we are `master' for
+ *
+ * Hint, SKB address this struct and refcnt via skb->nfct and
+ * helpers nf_conntrack_get() and nf_conntrack_put().
+ * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt,
+ * beware nf_ct_get() is different and don't inc refcnt.
+ */
struct nf_conntrack ct_general;
spinlock_t lock;
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 356bef5..965693e 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -408,21 +408,21 @@ EXPORT_SYMBOL_GPL(nf_conntrack_find_get);
static void __nf_conntrack_hash_insert(struct nf_conn *ct,
unsigned int hash,
- unsigned int repl_hash)
+ unsigned int reply_hash)
{
struct net *net = nf_ct_net(ct);
hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
&net->ct.hash[hash]);
hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode,
- &net->ct.hash[repl_hash]);
+ &net->ct.hash[reply_hash]);
}
int
nf_conntrack_hash_check_insert(struct nf_conn *ct)
{
struct net *net = nf_ct_net(ct);
- unsigned int hash, repl_hash;
+ unsigned int hash, reply_hash;
struct nf_conntrack_tuple_hash *h;
struct hlist_nulls_node *n;
u16 zone;
@@ -430,7 +430,7 @@ nf_conntrack_hash_check_insert(struct nf_conn *ct)
zone = nf_ct_zone(ct);
hash = hash_conntrack(net, zone,
&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
- repl_hash = hash_conntrack(net, zone,
+ reply_hash = hash_conntrack(net, zone,
&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
spin_lock_bh(&nf_conntrack_lock);
@@ -441,7 +441,7 @@ nf_conntrack_hash_check_insert(struct nf_conn *ct)
&h->tuple) &&
zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
goto out;
- hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
+ hlist_nulls_for_each_entry(h, n, &net->ct.hash[reply_hash], hnnode)
if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
&h->tuple) &&
zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
@@ -451,7 +451,7 @@ nf_conntrack_hash_check_insert(struct nf_conn *ct)
smp_wmb();
/* The caller holds a reference to this object */
atomic_set(&ct->ct_general.use, 2);
- __nf_conntrack_hash_insert(ct, hash, repl_hash);
+ __nf_conntrack_hash_insert(ct, hash, reply_hash);
NF_CT_STAT_INC(net, insert);
spin_unlock_bh(&nf_conntrack_lock);
@@ -483,7 +483,7 @@ EXPORT_SYMBOL_GPL(nf_conntrack_tmpl_insert);
int
__nf_conntrack_confirm(struct sk_buff *skb)
{
- unsigned int hash, repl_hash;
+ unsigned int hash, reply_hash;
struct nf_conntrack_tuple_hash *h;
struct nf_conn *ct;
struct nf_conn_help *help;
@@ -507,7 +507,7 @@ __nf_conntrack_confirm(struct sk_buff *skb)
/* reuse the hash saved before */
hash = *(unsigned long *)&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev;
hash = hash_bucket(hash, net);
- repl_hash = hash_conntrack(net, zone,
+ reply_hash = hash_conntrack(net, zone,
&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
/* We're not in hash table, and we refuse to set up related
@@ -540,7 +540,7 @@ __nf_conntrack_confirm(struct sk_buff *skb)
&h->tuple) &&
zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
goto out;
- hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode)
+ hlist_nulls_for_each_entry(h, n, &net->ct.hash[reply_hash], hnnode)
if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple,
&h->tuple) &&
zone == nf_ct_zone(nf_ct_tuplehash_to_ctrack(h)))
@@ -570,7 +570,7 @@ __nf_conntrack_confirm(struct sk_buff *skb)
* guarantee that no other CPU can find the conntrack before the above
* stores are visible.
*/
- __nf_conntrack_hash_insert(ct, hash, repl_hash);
+ __nf_conntrack_hash_insert(ct, hash, reply_hash);
NF_CT_STAT_INC(net, insert);
spin_unlock_bh(&nf_conntrack_lock);
--
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