[NETNS][IPV6] fib6_rules - handle several network namespaces

The fib6_rules_ops is moved to the network namespace structure.  All
references are changed to have it relatively to it.

Each time a network namespace is created a new fib6_rules_ops is
allocated, initialized and stored into the network namespace
structure.

The common part of the fib rules is namespace aware, so it is quite
easy to retrieve the network namespace from the rules and use it in
the different callbacks.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/netns/ipv6.h

@@ -41,6 +41,7 @@ struct netns_ipv6 {
 	struct fib6_table       *fib6_main_tbl;
 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
 	struct fib6_table       *fib6_local_tbl;
+	struct fib_rules_ops    *fib6_rules_ops;
 #endif
 	struct sock		**icmp_sk;
 };

net/ipv6/fib6_rules.c

@@ -29,16 +29,14 @@ struct fib6_rule
 	u8			tclass;
 };
 
-static struct fib_rules_ops *fib6_rules_ops;
-
 struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi *fl,
 				   int flags, pol_lookup_t lookup)
 {
 	struct fib_lookup_arg arg = {
 		.lookup_ptr = lookup,
 	};
 
-	fib_rules_lookup(fib6_rules_ops, fl, flags, &arg);
+	fib_rules_lookup(net->ipv6.fib6_rules_ops, fl, flags, &arg);
 	if (arg.rule)
 		fib_rule_put(arg.rule);
 
@@ -71,7 +69,7 @@ static int fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
 		goto discard_pkt;
 	}
 
-	table = fib6_get_table(&init_net, rule->table);
+	table = fib6_get_table(rule->fr_net, rule->table);
 	if (table)
 		rt = lookup(table, flp, flags);
 
@@ -145,13 +143,14 @@ static int fib6_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 			       struct nlattr **tb)
 {
 	int err = -EINVAL;
+	struct net *net = skb->sk->sk_net;
 	struct fib6_rule *rule6 = (struct fib6_rule *) rule;
 
 	if (rule->action == FR_ACT_TO_TBL) {
 		if (rule->table == RT6_TABLE_UNSPEC)
 			goto errout;
 
-		if (fib6_new_table(&init_net, rule->table) == NULL) {
+		if (fib6_new_table(net, rule->table) == NULL) {
 			err = -ENOBUFS;
 			goto errout;
 		}
@@ -251,49 +250,60 @@ static struct fib_rules_ops fib6_rules_ops_template = {
 	.fro_net		= &init_net,
 };
 
-static int __init fib6_default_rules_init(void)
+static int fib6_rules_net_init(struct net *net)
 {
-	int err;
+	int err = -ENOMEM;
 
-	fib6_rules_ops = kmemdup(&fib6_rules_ops_template,
-				 sizeof(*fib6_rules_ops), GFP_KERNEL);
-	if (!fib6_rules_ops)
-		return -ENOMEM;
+	net->ipv6.fib6_rules_ops = kmemdup(&fib6_rules_ops_template,
+					   sizeof(*net->ipv6.fib6_rules_ops),
+					   GFP_KERNEL);
+	if (!net->ipv6.fib6_rules_ops)
+		goto out;
 
-	INIT_LIST_HEAD(&fib6_rules_ops->rules_list);
+	net->ipv6.fib6_rules_ops->fro_net = net;
+	INIT_LIST_HEAD(&net->ipv6.fib6_rules_ops->rules_list);
 
-	err = fib_default_rule_add(fib6_rules_ops, 0,
+	err = fib_default_rule_add(net->ipv6.fib6_rules_ops, 0,
 				   RT6_TABLE_LOCAL, FIB_RULE_PERMANENT);
-	if (err < 0)
-		return err;
-	err = fib_default_rule_add(fib6_rules_ops, 0x7FFE, RT6_TABLE_MAIN, 0);
-	if (err < 0)
-		return err;
-	return 0;
-}
-
-int __init fib6_rules_init(void)
-{
-	int ret;
+	if (err)
+		goto out_fib6_rules_ops;
 
-	ret = fib6_default_rules_init();
-	if (ret)
-		goto out;
+	err = fib_default_rule_add(net->ipv6.fib6_rules_ops,
+				   0x7FFE, RT6_TABLE_MAIN, 0);
+	if (err)
+		goto out_fib6_default_rule_add;
 
-	ret = fib_rules_register(fib6_rules_ops);
-	if (ret)
-		goto out_default_rules_init;
+	err = fib_rules_register(net->ipv6.fib6_rules_ops);
+	if (err)
+		goto out_fib6_default_rule_add;
 out:
-	return ret;
+	return err;
 
-out_default_rules_init:
-	fib_rules_cleanup_ops(fib6_rules_ops);
-	kfree(fib6_rules_ops);
+out_fib6_default_rule_add:
+	fib_rules_cleanup_ops(net->ipv6.fib6_rules_ops);
+out_fib6_rules_ops:
+	kfree(net->ipv6.fib6_rules_ops);
 	goto out;
 }
 
+static void fib6_rules_net_exit(struct net *net)
+{
+	fib_rules_unregister(net->ipv6.fib6_rules_ops);
+	kfree(net->ipv6.fib6_rules_ops);
+}
+
+static struct pernet_operations fib6_rules_net_ops = {
+	.init = fib6_rules_net_init,
+	.exit = fib6_rules_net_exit,
+};
+
+int __init fib6_rules_init(void)
+{
+	return register_pernet_subsys(&fib6_rules_net_ops);
+}
+
+
 void fib6_rules_cleanup(void)
 {
-	fib_rules_unregister(fib6_rules_ops);
-	kfree(fib6_rules_ops);
+	return unregister_pernet_subsys(&fib6_rules_net_ops);
 }