[NETNS]: Place fib tables into netns.

The preparatory work has been done. All we need is to substitute
fib_table_hash with net->ipv4.fib_table_hash. Netns context is
available when required.

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/ip_fib.h

@@ -120,8 +120,6 @@ struct fib_result_nl {
 	int             err;      
 };
 
-extern struct hlist_head fib_table_hash[];
-
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 
 #define FIB_RES_NH(res)		((res).fi->fib_nh[(res).nh_sel])
@@ -170,8 +168,8 @@ static inline struct fib_table *fib_get_table(struct net *net, u32 id)
 	struct hlist_head *ptr;
 
 	ptr = id == RT_TABLE_LOCAL ?
-		&fib_table_hash[TABLE_LOCAL_INDEX] :
-		&fib_table_hash[TABLE_MAIN_INDEX];
+		&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX] :
+		&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX];
 	return hlist_entry(ptr->first, struct fib_table, tb_hlist);
 }
 

include/net/netns/ipv4.h

@@ -8,6 +8,7 @@
 struct ctl_table_header;
 struct ipv4_devconf;
 struct fib_rules_ops;
+struct hlist_head;
 
 struct netns_ipv4 {
 #ifdef CONFIG_SYSCTL
@@ -18,5 +19,6 @@ struct netns_ipv4 {
 #ifdef CONFIG_IP_MULTIPLE_TABLES
 	struct fib_rules_ops	*rules_ops;
 #endif
+	struct hlist_head	*fib_table_hash;
 };
 #endif

net/ipv4/fib_frontend.c

@@ -50,7 +50,6 @@
 #define FFprint(a...) printk(KERN_DEBUG a)
 
 static struct sock *fibnl;
-struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ];
 
 #ifndef CONFIG_IP_MULTIPLE_TABLES
 
@@ -67,9 +66,9 @@ static int __net_init fib4_rules_init(struct net *net)
 		goto fail;
 
 	hlist_add_head_rcu(&local_table->tb_hlist,
-				&fib_table_hash[TABLE_LOCAL_INDEX]);
+				&net->ipv4.fib_table_hash[TABLE_LOCAL_INDEX]);
 	hlist_add_head_rcu(&main_table->tb_hlist,
-				&fib_table_hash[TABLE_MAIN_INDEX]);
+				&net->ipv4.fib_table_hash[TABLE_MAIN_INDEX]);
 	return 0;
 
 fail:
@@ -92,7 +91,7 @@ struct fib_table *fib_new_table(struct net *net, u32 id)
 	if (!tb)
 		return NULL;
 	h = id & (FIB_TABLE_HASHSZ - 1);
-	hlist_add_head_rcu(&tb->tb_hlist, &fib_table_hash[h]);
+	hlist_add_head_rcu(&tb->tb_hlist, &net->ipv4.fib_table_hash[h]);
 	return tb;
 }
 
@@ -100,13 +99,16 @@ struct fib_table *fib_get_table(struct net *net, u32 id)
 {
 	struct fib_table *tb;
 	struct hlist_node *node;
+	struct hlist_head *head;
 	unsigned int h;
 
 	if (id == 0)
 		id = RT_TABLE_MAIN;
 	h = id & (FIB_TABLE_HASHSZ - 1);
+
 	rcu_read_lock();
-	hlist_for_each_entry_rcu(tb, node, &fib_table_hash[h], tb_hlist) {
+	head = &net->ipv4.fib_table_hash[h];
+	hlist_for_each_entry_rcu(tb, node, head, tb_hlist) {
 		if (tb->tb_id == id) {
 			rcu_read_unlock();
 			return tb;
@@ -117,15 +119,17 @@ struct fib_table *fib_get_table(struct net *net, u32 id)
 }
 #endif /* CONFIG_IP_MULTIPLE_TABLES */
 
-static void fib_flush(void)
+static void fib_flush(struct net *net)
 {
 	int flushed = 0;
 	struct fib_table *tb;
 	struct hlist_node *node;
+	struct hlist_head *head;
 	unsigned int h;
 
 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
-		hlist_for_each_entry(tb, node, &fib_table_hash[h], tb_hlist)
+		head = &net->ipv4.fib_table_hash[h];
+		hlist_for_each_entry(tb, node, head, tb_hlist)
 			flushed += tb->tb_flush(tb);
 	}
 
@@ -620,6 +624,7 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 	unsigned int e = 0, s_e;
 	struct fib_table *tb;
 	struct hlist_node *node;
+	struct hlist_head *head;
 	int dumped = 0;
 
 	if (net != &init_net)
@@ -634,7 +639,8 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 
 	for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
 		e = 0;
-		hlist_for_each_entry(tb, node, &fib_table_hash[h], tb_hlist) {
+		head = &net->ipv4.fib_table_hash[h];
+		hlist_for_each_entry(tb, node, head, tb_hlist) {
 			if (e < s_e)
 				goto next;
 			if (dumped)
@@ -797,7 +803,7 @@ static void fib_del_ifaddr(struct in_ifaddr *ifa)
 			   for stray nexthop entries, then ignite fib_flush.
 			*/
 			if (fib_sync_down(ifa->ifa_local, NULL, 0))
-				fib_flush();
+				fib_flush(&init_net);
 		}
 	}
 #undef LOCAL_OK
@@ -882,7 +888,7 @@ static void nl_fib_lookup_exit(struct net *net)
 static void fib_disable_ip(struct net_device *dev, int force)
 {
 	if (fib_sync_down(0, dev, force))
-		fib_flush();
+		fib_flush(&init_net);
 	rt_cache_flush(0);
 	arp_ifdown(dev);
 }
@@ -963,8 +969,13 @@ static int __net_init ip_fib_net_init(struct net *net)
 {
 	unsigned int i;
 
+	net->ipv4.fib_table_hash = kzalloc(
+			sizeof(struct hlist_head)*FIB_TABLE_HASHSZ, GFP_KERNEL);
+	if (net->ipv4.fib_table_hash == NULL)
+		return -ENOMEM;
+
 	for (i = 0; i < FIB_TABLE_HASHSZ; i++)
-		INIT_HLIST_HEAD(&fib_table_hash[i]);
+		INIT_HLIST_HEAD(&net->ipv4.fib_table_hash[i]);
 
 	return fib4_rules_init(net);
 }
@@ -982,13 +993,14 @@ static void __net_exit ip_fib_net_exit(struct net *net)
 		struct hlist_head *head;
 		struct hlist_node *node, *tmp;
 
-		head = &fib_table_hash[i];
+		head = &net->ipv4.fib_table_hash[i];
 		hlist_for_each_entry_safe(tb, node, tmp, head, tb_hlist) {
 			hlist_del(node);
 			tb->tb_flush(tb);
 			kfree(tb);
 		}
 	}
+	kfree(net->ipv4.fib_table_hash);
 }
 
 static int __net_init fib_net_init(struct net *net)