1 files changed, 23 insertions, 38 deletions

diff --git a/net/netfilter/xt_helper.c b/net/netfilter/xt_helper.c
index c139b2f43a10..0a1f4c6bcdef 100644
--- a/net/netfilter/xt_helper.c
+++ b/net/netfilter/xt_helper.c
@@ -22,13 +22,8 @@ MODULE_DESCRIPTION("iptables helper match module");
 MODULE_ALIAS("ipt_helper");
 MODULE_ALIAS("ip6t_helper");
 
-#if 0
-#define DEBUGP printk
-#else
-#define DEBUGP(format, args...)
-#endif
 
-static int
+static bool
 match(const struct sk_buff *skb,
       const struct net_device *in,
       const struct net_device *out,
@@ -36,61 +31,51 @@ match(const struct sk_buff *skb,
       const void *matchinfo,
       int offset,
       unsigned int protoff,
-      int *hotdrop)
+      bool *hotdrop)
 {
 	const struct xt_helper_info *info = matchinfo;
-	struct nf_conn *ct;
-	struct nf_conn_help *master_help;
+	const struct nf_conn *ct;
+	const struct nf_conn_help *master_help;
+	const struct nf_conntrack_helper *helper;
 	enum ip_conntrack_info ctinfo;
-	int ret = info->invert;
+	bool ret = info->invert;
 
-	ct = nf_ct_get((struct sk_buff *)skb, &ctinfo);
-	if (!ct) {
-		DEBUGP("xt_helper: Eek! invalid conntrack?\n");
+	ct = nf_ct_get(skb, &ctinfo);
+	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 ^= 1;
+		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;
 }
 
-static int check(const char *tablename,
-		 const void *inf,
-		 const struct xt_match *match,
-		 void *matchinfo,
-		 unsigned int hook_mask)
+static bool check(const char *tablename,
+		  const void *inf,
+		  const struct xt_match *match,
+		  void *matchinfo,
+		  unsigned int hook_mask)
 {
 	struct xt_helper_info *info = matchinfo;
 
 	if (nf_ct_l3proto_try_module_get(match->family) < 0) {
 		printk(KERN_WARNING "can't load conntrack support for "
 				    "proto=%d\n", match->family);
-		return 0;
+		return false;
 	}
 	info->name[29] = '\0';
-	return 1;
+	return true;
 }
 
 static void
@@ -99,7 +84,7 @@ destroy(const struct xt_match *match, void *matchinfo)
 	nf_ct_l3proto_module_put(match->family);
 }
 
-static struct xt_match xt_helper_match[] = {
+static struct xt_match xt_helper_match[] __read_mostly = {
 	{
 		.name		= "helper",
 		.family		= AF_INET,