netfilter: ipt_CLUSTERIP: use proper net namespace to operate CLUSTERIP

we can allow users in uninit net namespace to operate ipt_CLUSTERIP
now.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/ipv4/netfilter/ipt_CLUSTERIP.c

@@ -99,7 +99,8 @@ clusterip_config_put(struct clusterip_config *c)
 static inline void
 clusterip_config_entry_put(struct clusterip_config *c)
 {
-	struct clusterip_net *cn = net_generic(&init_net, clusterip_net_id);
+	struct net *net = dev_net(c->dev);
+	struct clusterip_net *cn = net_generic(net, clusterip_net_id);
 
 	local_bh_disable();
 	if (atomic_dec_and_lock(&c->entries, &cn->lock)) {
@@ -381,7 +382,7 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par)
 
 	/* FIXME: further sanity checks */
 
-	config = clusterip_config_find_get(&init_net, e->ip.dst.s_addr, 1);
+	config = clusterip_config_find_get(par->net, e->ip.dst.s_addr, 1);
 	if (!config) {
 		if (!(cipinfo->flags & CLUSTERIP_FLAG_NEW)) {
 			pr_info("no config found for %pI4, need 'new'\n",
@@ -395,7 +396,7 @@ static int clusterip_tg_check(const struct xt_tgchk_param *par)
 				return -EINVAL;
 			}
 
-			dev = dev_get_by_name(&init_net, e->ip.iniface);
+			dev = dev_get_by_name(par->net, e->ip.iniface);
 			if (!dev) {
 				pr_info("no such interface %s\n",
 					e->ip.iniface);
@@ -503,6 +504,7 @@ arp_mangle(unsigned int hook,
 	struct arphdr *arp = arp_hdr(skb);
 	struct arp_payload *payload;
 	struct clusterip_config *c;
+	struct net *net = dev_net(in ? in : out);
 
 	/* we don't care about non-ethernet and non-ipv4 ARP */
 	if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
@@ -519,7 +521,7 @@ arp_mangle(unsigned int hook,
 
 	/* if there is no clusterip configuration for the arp reply's
 	 * source ip, we don't want to mangle it */
-	c = clusterip_config_find_get(&init_net, payload->src_ip, 0);
+	c = clusterip_config_find_get(net, payload->src_ip, 0);
 	if (!c)
 		return NF_ACCEPT;