1 files changed, 101 insertions, 33 deletions

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 23b9b3e86f4c..872494e6e6eb 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -52,12 +52,12 @@ static int __net_init fib4_rules_init(struct net *net)
 {
 	struct fib_table *local_table, *main_table;
 
-	local_table = fib_trie_table(RT_TABLE_LOCAL);
-	if (local_table == NULL)
+	main_table  = fib_trie_table(RT_TABLE_MAIN, NULL);
+	if (!main_table)
 		return -ENOMEM;
 
-	main_table  = fib_trie_table(RT_TABLE_MAIN);
-	if (main_table == NULL)
+	local_table = fib_trie_table(RT_TABLE_LOCAL, main_table);
+	if (!local_table)
 		goto fail;
 
 	hlist_add_head_rcu(&local_table->tb_hlist,
@@ -67,14 +67,14 @@ static int __net_init fib4_rules_init(struct net *net)
 	return 0;
 
 fail:
-	fib_free_table(local_table);
+	fib_free_table(main_table);
 	return -ENOMEM;
 }
 #else
 
 struct fib_table *fib_new_table(struct net *net, u32 id)
 {
-	struct fib_table *tb;
+	struct fib_table *tb, *alias = NULL;
 	unsigned int h;
 
 	if (id == 0)
@@ -83,23 +83,23 @@ struct fib_table *fib_new_table(struct net *net, u32 id)
 	if (tb)
 		return tb;
 
-	tb = fib_trie_table(id);
+	if (id == RT_TABLE_LOCAL)
+		alias = fib_new_table(net, RT_TABLE_MAIN);
+
+	tb = fib_trie_table(id, alias);
 	if (!tb)
 		return NULL;
 
 	switch (id) {
 	case RT_TABLE_LOCAL:
-		net->ipv4.fib_local = tb;
+		rcu_assign_pointer(net->ipv4.fib_local, tb);
 		break;
-
 	case RT_TABLE_MAIN:
-		net->ipv4.fib_main = tb;
+		rcu_assign_pointer(net->ipv4.fib_main, tb);
 		break;
-
 	case RT_TABLE_DEFAULT:
-		net->ipv4.fib_default = tb;
+		rcu_assign_pointer(net->ipv4.fib_default, tb);
 		break;
-
 	default:
 		break;
 	}
@@ -129,16 +129,62 @@ struct fib_table *fib_get_table(struct net *net, u32 id)
 }
 #endif /* CONFIG_IP_MULTIPLE_TABLES */
 
+static void fib_replace_table(struct net *net, struct fib_table *old,
+			      struct fib_table *new)
+{
+#ifdef CONFIG_IP_MULTIPLE_TABLES
+	switch (new->tb_id) {
+	case RT_TABLE_LOCAL:
+		rcu_assign_pointer(net->ipv4.fib_local, new);
+		break;
+	case RT_TABLE_MAIN:
+		rcu_assign_pointer(net->ipv4.fib_main, new);
+		break;
+	case RT_TABLE_DEFAULT:
+		rcu_assign_pointer(net->ipv4.fib_default, new);
+		break;
+	default:
+		break;
+	}
+
+#endif
+	/* replace the old table in the hlist */
+	hlist_replace_rcu(&old->tb_hlist, &new->tb_hlist);
+}
+
+int fib_unmerge(struct net *net)
+{
+	struct fib_table *old, *new;
+
+	/* attempt to fetch local table if it has been allocated */
+	old = fib_get_table(net, RT_TABLE_LOCAL);
+	if (!old)
+		return 0;
+
+	new = fib_trie_unmerge(old);
+	if (!new)
+		return -ENOMEM;
+
+	/* replace merged table with clean table */
+	if (new != old) {
+		fib_replace_table(net, old, new);
+		fib_free_table(old);
+	}
+
+	return 0;
+}
+
 static void fib_flush(struct net *net)
 {
 	int flushed = 0;
-	struct fib_table *tb;
-	struct hlist_head *head;
 	unsigned int h;
 
 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
-		head = &net->ipv4.fib_table_hash[h];
-		hlist_for_each_entry(tb, head, tb_hlist)
+		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
+		struct hlist_node *tmp;
+		struct fib_table *tb;
+
+		hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
 			flushed += fib_table_flush(tb);
 	}
 
@@ -146,6 +192,19 @@ static void fib_flush(struct net *net)
 		rt_cache_flush(net);
 }
 
+void fib_flush_external(struct net *net)
+{
+	struct fib_table *tb;
+	struct hlist_head *head;
+	unsigned int h;
+
+	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
+		head = &net->ipv4.fib_table_hash[h];
+		hlist_for_each_entry(tb, head, tb_hlist)
+			fib_table_flush_external(tb);
+	}
+}
+
 /*
  * Find address type as if only "dev" was present in the system. If
  * on_dev is NULL then all interfaces are taken into consideration.
@@ -427,7 +486,7 @@ static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
 			for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
 				if (strcmp(ifa->ifa_label, devname) == 0)
 					break;
-			if (ifa == NULL)
+			if (!ifa)
 				return -ENODEV;
 			cfg->fc_prefsrc = ifa->ifa_local;
 		}
@@ -455,7 +514,7 @@ static int rtentry_to_fib_config(struct net *net, int cmd, struct rtentry *rt,
 		int len = 0;
 
 		mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL);
-		if (mx == NULL)
+		if (!mx)
 			return -ENOMEM;
 
 		if (rt->rt_flags & RTF_MTU)
@@ -617,7 +676,7 @@ static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh)
 		goto errout;
 
 	tb = fib_get_table(net, cfg.fc_table);
-	if (tb == NULL) {
+	if (!tb) {
 		err = -ESRCH;
 		goto errout;
 	}
@@ -639,7 +698,7 @@ static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh)
 		goto errout;
 
 	tb = fib_new_table(net, cfg.fc_table);
-	if (tb == NULL) {
+	if (!tb) {
 		err = -ENOBUFS;
 		goto errout;
 	}
@@ -665,10 +724,12 @@ static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
 	s_h = cb->args[0];
 	s_e = cb->args[1];
 
+	rcu_read_lock();
+
 	for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
 		e = 0;
 		head = &net->ipv4.fib_table_hash[h];
-		hlist_for_each_entry(tb, head, tb_hlist) {
+		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
 			if (e < s_e)
 				goto next;
 			if (dumped)
@@ -682,6 +743,8 @@ next:
 		}
 	}
 out:
+	rcu_read_unlock();
+
 	cb->args[1] = e;
 	cb->args[0] = h;
 
@@ -716,7 +779,7 @@ static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifad
 	else
 		tb = fib_new_table(net, RT_TABLE_LOCAL);
 
-	if (tb == NULL)
+	if (!tb)
 		return;
 
 	cfg.fc_table = tb->tb_id;
@@ -743,7 +806,7 @@ void fib_add_ifaddr(struct in_ifaddr *ifa)
 
 	if (ifa->ifa_flags & IFA_F_SECONDARY) {
 		prim = inet_ifa_byprefix(in_dev, prefix, mask);
-		if (prim == NULL) {
+		if (!prim) {
 			pr_warn("%s: bug: prim == NULL\n", __func__);
 			return;
 		}
@@ -797,7 +860,7 @@ void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim)
 
 	if (ifa->ifa_flags & IFA_F_SECONDARY) {
 		prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
-		if (prim == NULL) {
+		if (!prim) {
 			pr_warn("%s: bug: prim == NULL\n", __func__);
 			return;
 		}
@@ -967,7 +1030,7 @@ static void nl_fib_input(struct sk_buff *skb)
 		return;
 
 	skb = netlink_skb_clone(skb, GFP_KERNEL);
-	if (skb == NULL)
+	if (!skb)
 		return;
 	nlh = nlmsg_hdr(skb);
 
@@ -988,7 +1051,7 @@ static int __net_init nl_fib_lookup_init(struct net *net)
 	};
 
 	sk = netlink_kernel_create(net, NETLINK_FIB_LOOKUP, &cfg);
-	if (sk == NULL)
+	if (!sk)
 		return -EAFNOSUPPORT;
 	net->ipv4.fibnl = sk;
 	return 0;
@@ -1026,7 +1089,7 @@ static int fib_inetaddr_event(struct notifier_block *this, unsigned long event,
 	case NETDEV_DOWN:
 		fib_del_ifaddr(ifa, NULL);
 		atomic_inc(&net->ipv4.dev_addr_genid);
-		if (ifa->ifa_dev->ifa_list == NULL) {
+		if (!ifa->ifa_dev->ifa_list) {
 			/* Last address was deleted from this interface.
 			 * Disable IP.
 			 */
@@ -1094,7 +1157,7 @@ static int __net_init ip_fib_net_init(struct net *net)
 	size = max_t(size_t, size, L1_CACHE_BYTES);
 
 	net->ipv4.fib_table_hash = kzalloc(size, GFP_KERNEL);
-	if (net->ipv4.fib_table_hash == NULL)
+	if (!net->ipv4.fib_table_hash)
 		return -ENOMEM;
 
 	err = fib4_rules_init(net);
@@ -1113,20 +1176,25 @@ static void ip_fib_net_exit(struct net *net)
 
 	rtnl_lock();
 #ifdef CONFIG_IP_MULTIPLE_TABLES
-	fib4_rules_exit(net);
+	RCU_INIT_POINTER(net->ipv4.fib_local, NULL);
+	RCU_INIT_POINTER(net->ipv4.fib_main, NULL);
+	RCU_INIT_POINTER(net->ipv4.fib_default, NULL);
 #endif
 	for (i = 0; i < FIB_TABLE_HASHSZ; i++) {
-		struct fib_table *tb;
-		struct hlist_head *head;
+		struct hlist_head *head = &net->ipv4.fib_table_hash[i];
 		struct hlist_node *tmp;
+		struct fib_table *tb;
 
-		head = &net->ipv4.fib_table_hash[i];
 		hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
 			hlist_del(&tb->tb_hlist);
 			fib_table_flush(tb);
 			fib_free_table(tb);
 		}
 	}
+
+#ifdef CONFIG_IP_MULTIPLE_TABLES
+	fib4_rules_exit(net);
+#endif
 	rtnl_unlock();
 	kfree(net->ipv4.fib_table_hash);
 }