[NETFILTER]: xt_helper: use RCU
The ->helper pointer is protected by RCU, no need to take
nf_conntrack_lock. Also remove excessive debugging.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/xt_helper.c b/net/netfilter/xt_helper.c
index d03acb0..0a1f4c6 100644
--- a/net/netfilter/xt_helper.c
+++ b/net/netfilter/xt_helper.c
@@ -22,11 +22,6 @@
MODULE_ALIAS("ipt_helper");
MODULE_ALIAS("ip6t_helper");
-#if 0
-#define DEBUGP printk
-#else
-#define DEBUGP(format, args...)
-#endif
static bool
match(const struct sk_buff *skb,
@@ -41,38 +36,28 @@
const struct xt_helper_info *info = matchinfo;
const struct nf_conn *ct;
const struct nf_conn_help *master_help;
+ const struct nf_conntrack_helper *helper;
enum ip_conntrack_info ctinfo;
bool ret = info->invert;
ct = nf_ct_get(skb, &ctinfo);
- if (!ct) {
- DEBUGP("xt_helper: Eek! invalid conntrack?\n");
+ if (!ct || !ct->master)
return ret;
- }
- if (!ct->master) {
- DEBUGP("xt_helper: conntrack %p has no master\n", ct);
- return ret;
- }
-
- read_lock_bh(&nf_conntrack_lock);
master_help = nfct_help(ct->master);
- if (!master_help || !master_help->helper) {
- DEBUGP("xt_helper: master ct %p has no helper\n",
- exp->expectant);
- goto out_unlock;
- }
+ if (!master_help)
+ return ret;
- DEBUGP("master's name = %s , info->name = %s\n",
- ct->master->helper->name, info->name);
+ /* rcu_read_lock()ed by nf_hook_slow */
+ helper = rcu_dereference(master_help->helper);
+ if (!helper)
+ return ret;
if (info->name[0] == '\0')
ret = !ret;
else
ret ^= !strncmp(master_help->helper->name, info->name,
strlen(master_help->helper->name));
-out_unlock:
- read_unlock_bh(&nf_conntrack_lock);
return ret;
}