[NETNS]: Namespacing IPv4 fib rules.

The final trick for rules: place fib4_rules_ops into struct net and
modify initialization path for this.
Acked-by: Benjamin Thery <benjamin.thery@bull.net>
Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/netns/ipv4.h

@@ -4,8 +4,10 @@
 
 #ifndef __NETNS_IPV4_H__
 #define __NETNS_IPV4_H__
+
 struct ctl_table_header;
 struct ipv4_devconf;
+struct fib_rules_ops;
 
 struct netns_ipv4 {
 #ifdef CONFIG_SYSCTL
@@ -13,5 +15,8 @@ struct netns_ipv4 {
 #endif
 	struct ipv4_devconf	*devconf_all;
 	struct ipv4_devconf	*devconf_dflt;
+#ifdef CONFIG_IP_MULTIPLE_TABLES
+	struct fib_rules_ops	*rules_ops;
+#endif
 };
 #endif

net/ipv4/fib_rules.c

@@ -32,8 +32,6 @@
 #include <net/ip_fib.h>
 #include <net/fib_rules.h>
 
-static struct fib_rules_ops fib4_rules_ops;
-
 struct fib4_rule
 {
 	struct fib_rule		common;
@@ -63,7 +61,7 @@ int fib_lookup(struct flowi *flp, struct fib_result *res)
 	};
 	int err;
 
-	err = fib_rules_lookup(&fib4_rules_ops, flp, 0, &arg);
+	err = fib_rules_lookup(init_net.ipv4.rules_ops, flp, 0, &arg);
 	res->r = arg.rule;
 
 	return err;
@@ -149,6 +147,7 @@ static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 			       struct nlmsghdr *nlh, struct fib_rule_hdr *frh,
 			       struct nlattr **tb)
 {
+	struct net *net = skb->sk->sk_net;
 	int err = -EINVAL;
 	struct fib4_rule *rule4 = (struct fib4_rule *) rule;
 
@@ -159,7 +158,7 @@ static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
 		if (rule->action == FR_ACT_TO_TBL) {
 			struct fib_table *table;
 
-			table = fib_empty_table(&init_net);
+			table = fib_empty_table(net);
 			if (table == NULL) {
 				err = -ENOBUFS;
 				goto errout;
@@ -250,9 +249,9 @@ static u32 fib4_rule_default_pref(struct fib_rules_ops *ops)
 	struct list_head *pos;
 	struct fib_rule *rule;
 
-	if (!list_empty(&fib4_rules_ops.rules_list)) {
-		pos = fib4_rules_ops.rules_list.next;
-		if (pos->next != &fib4_rules_ops.rules_list) {
+	if (!list_empty(&ops->rules_list)) {
+		pos = ops->rules_list.next;
+		if (pos->next != &ops->rules_list) {
 			rule = list_entry(pos->next, struct fib_rule, list);
 			if (rule->pref)
 				return rule->pref - 1;
@@ -274,7 +273,7 @@ static void fib4_rule_flush_cache(void)
 	rt_cache_flush(-1);
 }
 
-static struct fib_rules_ops fib4_rules_ops = {
+static struct fib_rules_ops fib4_rules_ops_template = {
 	.family		= AF_INET,
 	.rule_size	= sizeof(struct fib4_rule),
 	.addr_size	= sizeof(u32),
@@ -288,24 +287,20 @@ static struct fib_rules_ops fib4_rules_ops = {
 	.flush_cache	= fib4_rule_flush_cache,
 	.nlgroup	= RTNLGRP_IPV4_RULE,
 	.policy		= fib4_rule_policy,
-	.rules_list	= LIST_HEAD_INIT(fib4_rules_ops.rules_list),
 	.owner		= THIS_MODULE,
 };
 
-static int __init fib_default_rules_init(void)
+static int fib_default_rules_init(struct fib_rules_ops *ops)
 {
 	int err;
 
-	err = fib_default_rule_add(&fib4_rules_ops, 0,
-				   RT_TABLE_LOCAL, FIB_RULE_PERMANENT);
+	err = fib_default_rule_add(ops, 0, RT_TABLE_LOCAL, FIB_RULE_PERMANENT);
 	if (err < 0)
 		return err;
-	err = fib_default_rule_add(&fib4_rules_ops, 0x7FFE,
-				   RT_TABLE_MAIN, 0);
+	err = fib_default_rule_add(ops, 0x7FFE, RT_TABLE_MAIN, 0);
 	if (err < 0)
 		return err;
-	err = fib_default_rule_add(&fib4_rules_ops, 0x7FFF,
-				   RT_TABLE_DEFAULT, 0);
+	err = fib_default_rule_add(ops, 0x7FFF, RT_TABLE_DEFAULT, 0);
 	if (err < 0)
 		return err;
 	return 0;
@@ -314,20 +309,29 @@ static int __init fib_default_rules_init(void)
 int __net_init fib4_rules_init(struct net *net)
 {
 	int err;
+	struct fib_rules_ops *ops;
+
+	ops = kmemdup(&fib4_rules_ops_template, sizeof(*ops), GFP_KERNEL);
+	if (ops == NULL)
+		return -ENOMEM;
+	INIT_LIST_HEAD(&ops->rules_list);
+	fib_rules_register(net, ops);
 
-	fib_rules_register(net, &fib4_rules_ops);
-	err = fib_default_rules_init();
+	err = fib_default_rules_init(ops);
 	if (err < 0)
 		goto fail;
+	net->ipv4.rules_ops = ops;
 	return 0;
 
 fail:
 	/* also cleans all rules already added */
-	fib_rules_unregister(net, &fib4_rules_ops);
+	fib_rules_unregister(net, ops);
+	kfree(ops);
 	return err;
 }
 
 void __net_exit fib4_rules_exit(struct net *net)
 {
-	fib_rules_unregister(net, &fib4_rules_ops);
+	fib_rules_unregister(net, net->ipv4.rules_ops);
+	kfree(net->ipv4.rules_ops);
 }