Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2455 insertions, 0 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
new file mode 100644
index 000000000..5ff67cb8b
--- /dev/null
+++ b/net/ipv6/ip6_fib.c
@@ -0,0 +1,2455 @@
+/*
+ *	Linux INET6 implementation
+ *	Forwarding Information Database
+ *
+ *	Authors:
+ *	Pedro Roque		<roque@di.fc.ul.pt>
+ *
+ *	This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ *	Changes:
+ *	Yuji SEKIYA @USAGI:	Support default route on router node;
+ *				remove ip6_null_entry from the top of
+ *				routing table.
+ *	Ville Nuorvala:		Fixed routing subtrees.
+ */
+
+#define pr_fmt(fmt) "IPv6: " fmt
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/net.h>
+#include <linux/route.h>
+#include <linux/netdevice.h>
+#include <linux/in6.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include <net/ipv6.h>
+#include <net/ndisc.h>
+#include <net/addrconf.h>
+#include <net/lwtunnel.h>
+#include <net/fib_notifier.h>
+
+#include <net/ip6_fib.h>
+#include <net/ip6_route.h>
+
+static struct kmem_cache *fib6_node_kmem __read_mostly;
+
+struct fib6_cleaner {
+	struct fib6_walker w;
+	struct net *net;
+	int (*func)(struct fib6_info *, void *arg);
+	int sernum;
+	void *arg;
+};
+
+#ifdef CONFIG_IPV6_SUBTREES
+#define FWS_INIT FWS_S
+#else
+#define FWS_INIT FWS_L
+#endif
+
+static struct fib6_info *fib6_find_prefix(struct net *net,
+					 struct fib6_table *table,
+					 struct fib6_node *fn);
+static struct fib6_node *fib6_repair_tree(struct net *net,
+					  struct fib6_table *table,
+					  struct fib6_node *fn);
+static int fib6_walk(struct net *net, struct fib6_walker *w);
+static int fib6_walk_continue(struct fib6_walker *w);
+
+/*
+ *	A routing update causes an increase of the serial number on the
+ *	affected subtree. This allows for cached routes to be asynchronously
+ *	tested when modifications are made to the destination cache as a
+ *	result of redirects, path MTU changes, etc.
+ */
+
+static void fib6_gc_timer_cb(struct timer_list *t);
+
+#define FOR_WALKERS(net, w) \
+	list_for_each_entry(w, &(net)->ipv6.fib6_walkers, lh)
+
+static void fib6_walker_link(struct net *net, struct fib6_walker *w)
+{
+	write_lock_bh(&net->ipv6.fib6_walker_lock);
+	list_add(&w->lh, &net->ipv6.fib6_walkers);
+	write_unlock_bh(&net->ipv6.fib6_walker_lock);
+}
+
+static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
+{
+	write_lock_bh(&net->ipv6.fib6_walker_lock);
+	list_del(&w->lh);
+	write_unlock_bh(&net->ipv6.fib6_walker_lock);
+}
+
+static int fib6_new_sernum(struct net *net)
+{
+	int new, old;
+
+	do {
+		old = atomic_read(&net->ipv6.fib6_sernum);
+		new = old < INT_MAX ? old + 1 : 1;
+	} while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
+				old, new) != old);
+	return new;
+}
+
+enum {
+	FIB6_NO_SERNUM_CHANGE = 0,
+};
+
+void fib6_update_sernum(struct net *net, struct fib6_info *f6i)
+{
+	struct fib6_node *fn;
+
+	fn = rcu_dereference_protected(f6i->fib6_node,
+			lockdep_is_held(&f6i->fib6_table->tb6_lock));
+	if (fn)
+		WRITE_ONCE(fn->fn_sernum, fib6_new_sernum(net));
+}
+
+/*
+ *	Auxiliary address test functions for the radix tree.
+ *
+ *	These assume a 32bit processor (although it will work on
+ *	64bit processors)
+ */
+
+/*
+ *	test bit
+ */
+#if defined(__LITTLE_ENDIAN)
+# define BITOP_BE32_SWIZZLE	(0x1F & ~7)
+#else
+# define BITOP_BE32_SWIZZLE	0
+#endif
+
+static __be32 addr_bit_set(const void *token, int fn_bit)
+{
+	const __be32 *addr = token;
+	/*
+	 * Here,
+	 *	1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)
+	 * is optimized version of
+	 *	htonl(1 << ((~fn_bit)&0x1F))
+	 * See include/asm-generic/bitops/le.h.
+	 */
+	return (__force __be32)(1 << ((~fn_bit ^ BITOP_BE32_SWIZZLE) & 0x1f)) &
+	       addr[fn_bit >> 5];
+}
+
+struct fib6_info *fib6_info_alloc(gfp_t gfp_flags)
+{
+	struct fib6_info *f6i;
+
+	f6i = kzalloc(sizeof(*f6i), gfp_flags);
+	if (!f6i)
+		return NULL;
+
+	f6i->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags);
+	if (!f6i->rt6i_pcpu) {
+		kfree(f6i);
+		return NULL;
+	}
+
+	INIT_LIST_HEAD(&f6i->fib6_siblings);
+	f6i->fib6_metrics = (struct dst_metrics *)&dst_default_metrics;
+
+	atomic_inc(&f6i->fib6_ref);
+
+	return f6i;
+}
+
+void fib6_info_destroy_rcu(struct rcu_head *head)
+{
+	struct fib6_info *f6i = container_of(head, struct fib6_info, rcu);
+	struct rt6_exception_bucket *bucket;
+	struct dst_metrics *m;
+
+	WARN_ON(f6i->fib6_node);
+
+	bucket = rcu_dereference_protected(f6i->rt6i_exception_bucket, 1);
+	if (bucket) {
+		f6i->rt6i_exception_bucket = NULL;
+		kfree(bucket);
+	}
+
+	if (f6i->rt6i_pcpu) {
+		int cpu;
+
+		for_each_possible_cpu(cpu) {
+			struct rt6_info **ppcpu_rt;
+			struct rt6_info *pcpu_rt;
+
+			ppcpu_rt = per_cpu_ptr(f6i->rt6i_pcpu, cpu);
+			pcpu_rt = *ppcpu_rt;
+			if (pcpu_rt) {
+				dst_dev_put(&pcpu_rt->dst);
+				dst_release(&pcpu_rt->dst);
+				*ppcpu_rt = NULL;
+			}
+		}
+
+		free_percpu(f6i->rt6i_pcpu);
+	}
+
+	lwtstate_put(f6i->fib6_nh.nh_lwtstate);
+
+	if (f6i->fib6_nh.nh_dev)
+		dev_put(f6i->fib6_nh.nh_dev);
+
+	m = f6i->fib6_metrics;
+	if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
+		kfree(m);
+
+	kfree(f6i);
+}
+EXPORT_SYMBOL_GPL(fib6_info_destroy_rcu);
+
+static struct fib6_node *node_alloc(struct net *net)
+{
+	struct fib6_node *fn;
+
+	fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
+	if (fn)
+		net->ipv6.rt6_stats->fib_nodes++;
+
+	return fn;
+}
+
+static void node_free_immediate(struct net *net, struct fib6_node *fn)
+{
+	kmem_cache_free(fib6_node_kmem, fn);
+	net->ipv6.rt6_stats->fib_nodes--;
+}
+
+static void node_free_rcu(struct rcu_head *head)
+{
+	struct fib6_node *fn = container_of(head, struct fib6_node, rcu);
+
+	kmem_cache_free(fib6_node_kmem, fn);
+}
+
+static void node_free(struct net *net, struct fib6_node *fn)
+{
+	call_rcu(&fn->rcu, node_free_rcu);
+	net->ipv6.rt6_stats->fib_nodes--;
+}
+
+static void fib6_free_table(struct fib6_table *table)
+{
+	inetpeer_invalidate_tree(&table->tb6_peers);
+	kfree(table);
+}
+
+static void fib6_link_table(struct net *net, struct fib6_table *tb)
+{
+	unsigned int h;
+
+	/*
+	 * Initialize table lock at a single place to give lockdep a key,
+	 * tables aren't visible prior to being linked to the list.
+	 */
+	spin_lock_init(&tb->tb6_lock);
+	h = tb->tb6_id & (FIB6_TABLE_HASHSZ - 1);
+
+	/*
+	 * No protection necessary, this is the only list mutatation
+	 * operation, tables never disappear once they exist.
+	 */
+	hlist_add_head_rcu(&tb->tb6_hlist, &net->ipv6.fib_table_hash[h]);
+}
+
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
+
+static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
+{
+	struct fib6_table *table;
+
+	table = kzalloc(sizeof(*table), GFP_ATOMIC);
+	if (table) {
+		table->tb6_id = id;
+		rcu_assign_pointer(table->tb6_root.leaf,
+				   net->ipv6.fib6_null_entry);
+		table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
+		inet_peer_base_init(&table->tb6_peers);
+	}
+
+	return table;
+}
+
+struct fib6_table *fib6_new_table(struct net *net, u32 id)
+{
+	struct fib6_table *tb;
+
+	if (id == 0)
+		id = RT6_TABLE_MAIN;
+	tb = fib6_get_table(net, id);
+	if (tb)
+		return tb;
+
+	tb = fib6_alloc_table(net, id);
+	if (tb)
+		fib6_link_table(net, tb);
+
+	return tb;
+}
+EXPORT_SYMBOL_GPL(fib6_new_table);
+
+struct fib6_table *fib6_get_table(struct net *net, u32 id)
+{
+	struct fib6_table *tb;
+	struct hlist_head *head;
+	unsigned int h;
+
+	if (id == 0)
+		id = RT6_TABLE_MAIN;
+	h = id & (FIB6_TABLE_HASHSZ - 1);
+	rcu_read_lock();
+	head = &net->ipv6.fib_table_hash[h];
+	hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
+		if (tb->tb6_id == id) {
+			rcu_read_unlock();
+			return tb;
+		}
+	}
+	rcu_read_unlock();
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(fib6_get_table);
+
+static void __net_init fib6_tables_init(struct net *net)
+{
+	fib6_link_table(net, net->ipv6.fib6_main_tbl);
+	fib6_link_table(net, net->ipv6.fib6_local_tbl);
+}
+#else
+
+struct fib6_table *fib6_new_table(struct net *net, u32 id)
+{
+	return fib6_get_table(net, id);
+}
+
+struct fib6_table *fib6_get_table(struct net *net, u32 id)
+{
+	  return net->ipv6.fib6_main_tbl;
+}
+
+struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
+				   const struct sk_buff *skb,
+				   int flags, pol_lookup_t lookup)
+{
+	struct rt6_info *rt;
+
+	rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
+	if (rt->dst.error == -EAGAIN) {
+		ip6_rt_put(rt);
+		rt = net->ipv6.ip6_null_entry;
+		dst_hold(&rt->dst);
+	}
+
+	return &rt->dst;
+}
+
+/* called with rcu lock held; no reference taken on fib6_info */
+struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
+			      int flags)
+{
+	return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6, flags);
+}
+
+static void __net_init fib6_tables_init(struct net *net)
+{
+	fib6_link_table(net, net->ipv6.fib6_main_tbl);
+}
+
+#endif
+
+unsigned int fib6_tables_seq_read(struct net *net)
+{
+	unsigned int h, fib_seq = 0;
+
+	rcu_read_lock();
+	for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
+		struct hlist_head *head = &net->ipv6.fib_table_hash[h];
+		struct fib6_table *tb;
+
+		hlist_for_each_entry_rcu(tb, head, tb6_hlist)
+			fib_seq += tb->fib_seq;
+	}
+	rcu_read_unlock();
+
+	return fib_seq;
+}
+
+static int call_fib6_entry_notifier(struct notifier_block *nb, struct net *net,
+				    enum fib_event_type event_type,
+				    struct fib6_info *rt)
+{
+	struct fib6_entry_notifier_info info = {
+		.rt = rt,
+	};
+
+	return call_fib6_notifier(nb, net, event_type, &info.info);
+}
+
+static int call_fib6_entry_notifiers(struct net *net,
+				     enum fib_event_type event_type,
+				     struct fib6_info *rt,
+				     struct netlink_ext_ack *extack)
+{
+	struct fib6_entry_notifier_info info = {
+		.info.extack = extack,
+		.rt = rt,
+	};
+
+	rt->fib6_table->fib_seq++;
+	return call_fib6_notifiers(net, event_type, &info.info);
+}
+
+struct fib6_dump_arg {
+	struct net *net;
+	struct notifier_block *nb;
+};
+
+static void fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
+{
+	if (rt == arg->net->ipv6.fib6_null_entry)
+		return;
+	call_fib6_entry_notifier(arg->nb, arg->net, FIB_EVENT_ENTRY_ADD, rt);
+}
+
+static int fib6_node_dump(struct fib6_walker *w)
+{
+	struct fib6_info *rt;
+
+	for_each_fib6_walker_rt(w)
+		fib6_rt_dump(rt, w->args);
+	w->leaf = NULL;
+	return 0;
+}
+
+static void fib6_table_dump(struct net *net, struct fib6_table *tb,
+			    struct fib6_walker *w)
+{
+	w->root = &tb->tb6_root;
+	spin_lock_bh(&tb->tb6_lock);
+	fib6_walk(net, w);
+	spin_unlock_bh(&tb->tb6_lock);
+}
+
+/* Called with rcu_read_lock() */
+int fib6_tables_dump(struct net *net, struct notifier_block *nb)
+{
+	struct fib6_dump_arg arg;
+	struct fib6_walker *w;
+	unsigned int h;
+
+	w = kzalloc(sizeof(*w), GFP_ATOMIC);
+	if (!w)
+		return -ENOMEM;
+
+	w->func = fib6_node_dump;
+	arg.net = net;
+	arg.nb = nb;
+	w->args = &arg;
+
+	for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
+		struct hlist_head *head = &net->ipv6.fib_table_hash[h];
+		struct fib6_table *tb;
+
+		hlist_for_each_entry_rcu(tb, head, tb6_hlist)
+			fib6_table_dump(net, tb, w);
+	}
+
+	kfree(w);
+
+	return 0;
+}
+
+static int fib6_dump_node(struct fib6_walker *w)
+{
+	int res;
+	struct fib6_info *rt;
+
+	for_each_fib6_walker_rt(w) {
+		res = rt6_dump_route(rt, w->args);
+		if (res < 0) {
+			/* Frame is full, suspend walking */
+			w->leaf = rt;
+			return 1;
+		}
+
+		/* Multipath routes are dumped in one route with the
+		 * RTA_MULTIPATH attribute. Jump 'rt' to point to the
+		 * last sibling of this route (no need to dump the
+		 * sibling routes again)
+		 */
+		if (rt->fib6_nsiblings)
+			rt = list_last_entry(&rt->fib6_siblings,
+					     struct fib6_info,
+					     fib6_siblings);
+	}
+	w->leaf = NULL;
+	return 0;
+}
+
+static void fib6_dump_end(struct netlink_callback *cb)
+{
+	struct net *net = sock_net(cb->skb->sk);
+	struct fib6_walker *w = (void *)cb->args[2];
+
+	if (w) {
+		if (cb->args[4]) {
+			cb->args[4] = 0;
+			fib6_walker_unlink(net, w);
+		}
+		cb->args[2] = 0;
+		kfree(w);
+	}
+	cb->done = (void *)cb->args[3];
+	cb->args[1] = 3;
+}
+
+static int fib6_dump_done(struct netlink_callback *cb)
+{
+	fib6_dump_end(cb);
+	return cb->done ? cb->done(cb) : 0;
+}
+
+static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
+			   struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	struct fib6_walker *w;
+	int res;
+
+	w = (void *)cb->args[2];
+	w->root = &table->tb6_root;
+
+	if (cb->args[4] == 0) {
+		w->count = 0;
+		w->skip = 0;
+
+		spin_lock_bh(&table->tb6_lock);
+		res = fib6_walk(net, w);
+		spin_unlock_bh(&table->tb6_lock);
+		if (res > 0) {
+			cb->args[4] = 1;
+			cb->args[5] = READ_ONCE(w->root->fn_sernum);
+		}
+	} else {
+		int sernum = READ_ONCE(w->root->fn_sernum);
+		if (cb->args[5] != sernum) {
+			/* Begin at the root if the tree changed */
+			cb->args[5] = sernum;
+			w->state = FWS_INIT;
+			w->node = w->root;
+			w->skip = w->count;
+		} else
+			w->skip = 0;
+
+		spin_lock_bh(&table->tb6_lock);
+		res = fib6_walk_continue(w);
+		spin_unlock_bh(&table->tb6_lock);
+		if (res <= 0) {
+			fib6_walker_unlink(net, w);
+			cb->args[4] = 0;
+		}
+	}
+
+	return res;
+}
+
+static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct net *net = sock_net(skb->sk);
+	unsigned int h, s_h;
+	unsigned int e = 0, s_e;
+	struct rt6_rtnl_dump_arg arg;
+	struct fib6_walker *w;
+	struct fib6_table *tb;
+	struct hlist_head *head;
+	int res = 0;
+
+	s_h = cb->args[0];
+	s_e = cb->args[1];
+
+	w = (void *)cb->args[2];
+	if (!w) {
+		/* New dump:
+		 *
+		 * 1. hook callback destructor.
+		 */
+		cb->args[3] = (long)cb->done;
+		cb->done = fib6_dump_done;
+
+		/*
+		 * 2. allocate and initialize walker.
+		 */
+		w = kzalloc(sizeof(*w), GFP_ATOMIC);
+		if (!w)
+			return -ENOMEM;
+		w->func = fib6_dump_node;
+		cb->args[2] = (long)w;
+	}
+
+	arg.skb = skb;
+	arg.cb = cb;
+	arg.net = net;
+	w->args = &arg;
+
+	rcu_read_lock();
+	for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
+		e = 0;
+		head = &net->ipv6.fib_table_hash[h];
+		hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
+			if (e < s_e)
+				goto next;
+			res = fib6_dump_table(tb, skb, cb);
+			if (res != 0)
+				goto out;
+next:
+			e++;
+		}
+	}
+out:
+	rcu_read_unlock();
+	cb->args[1] = e;
+	cb->args[0] = h;
+
+	res = res < 0 ? res : skb->len;
+	if (res <= 0)
+		fib6_dump_end(cb);
+	return res;
+}
+
+void fib6_metric_set(struct fib6_info *f6i, int metric, u32 val)
+{
+	if (!f6i)
+		return;
+
+	if (f6i->fib6_metrics == &dst_default_metrics) {
+		struct dst_metrics *p = kzalloc(sizeof(*p), GFP_ATOMIC);
+
+		if (!p)
+			return;
+
+		refcount_set(&p->refcnt, 1);
+		f6i->fib6_metrics = p;
+	}
+
+	f6i->fib6_metrics->metrics[metric - 1] = val;
+}
+
+/*
+ *	Routing Table
+ *
+ *	return the appropriate node for a routing tree "add" operation
+ *	by either creating and inserting or by returning an existing
+ *	node.
+ */
+
+static struct fib6_node *fib6_add_1(struct net *net,
+				    struct fib6_table *table,
+				    struct fib6_node *root,
+				    struct in6_addr *addr, int plen,
+				    int offset, int allow_create,
+				    int replace_required,
+				    struct netlink_ext_ack *extack)
+{
+	struct fib6_node *fn, *in, *ln;
+	struct fib6_node *pn = NULL;
+	struct rt6key *key;
+	int	bit;
+	__be32	dir = 0;
+
+	RT6_TRACE("fib6_add_1\n");
+
+	/* insert node in tree */
+
+	fn = root;
+
+	do {
+		struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
+					    lockdep_is_held(&table->tb6_lock));
+		key = (struct rt6key *)((u8 *)leaf + offset);
+
+		/*
+		 *	Prefix match
+		 */
+		if (plen < fn->fn_bit ||
+		    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) {
+			if (!allow_create) {
+				if (replace_required) {
+					NL_SET_ERR_MSG(extack,
+						       "Can not replace route - no match found");
+					pr_warn("Can't replace route, no match found\n");
+					return ERR_PTR(-ENOENT);
+				}
+				pr_warn("NLM_F_CREATE should be set when creating new route\n");
+			}
+			goto insert_above;
+		}
+
+		/*
+		 *	Exact match ?
+		 */
+
+		if (plen == fn->fn_bit) {
+			/* clean up an intermediate node */
+			if (!(fn->fn_flags & RTN_RTINFO)) {
+				RCU_INIT_POINTER(fn->leaf, NULL);
+				fib6_info_release(leaf);
+			/* remove null_entry in the root node */
+			} else if (fn->fn_flags & RTN_TL_ROOT &&
+				   rcu_access_pointer(fn->leaf) ==
+				   net->ipv6.fib6_null_entry) {
+				RCU_INIT_POINTER(fn->leaf, NULL);
+			}
+
+			return fn;
+		}
+
+		/*
+		 *	We have more bits to go
+		 */
+
+		/* Try to walk down on tree. */
+		dir = addr_bit_set(addr, fn->fn_bit);
+		pn = fn;
+		fn = dir ?
+		     rcu_dereference_protected(fn->right,
+					lockdep_is_held(&table->tb6_lock)) :
+		     rcu_dereference_protected(fn->left,
+					lockdep_is_held(&table->tb6_lock));
+	} while (fn);
+
+	if (!allow_create) {
+		/* We should not create new node because
+		 * NLM_F_REPLACE was specified without NLM_F_CREATE
+		 * I assume it is safe to require NLM_F_CREATE when
+		 * REPLACE flag is used! Later we may want to remove the
+		 * check for replace_required, because according
+		 * to netlink specification, NLM_F_CREATE
+		 * MUST be specified if new route is created.
+		 * That would keep IPv6 consistent with IPv4
+		 */
+		if (replace_required) {
+			NL_SET_ERR_MSG(extack,
+				       "Can not replace route - no match found");
+			pr_warn("Can't replace route, no match found\n");
+			return ERR_PTR(-ENOENT);
+		}
+		pr_warn("NLM_F_CREATE should be set when creating new route\n");
+	}
+	/*
+	 *	We walked to the bottom of tree.
+	 *	Create new leaf node without children.
+	 */
+
+	ln = node_alloc(net);
+
+	if (!ln)
+		return ERR_PTR(-ENOMEM);
+	ln->fn_bit = plen;
+	RCU_INIT_POINTER(ln->parent, pn);
+
+	if (dir)
+		rcu_assign_pointer(pn->right, ln);
+	else
+		rcu_assign_pointer(pn->left, ln);
+
+	return ln;
+
+
+insert_above:
+	/*
+	 * split since we don't have a common prefix anymore or
+	 * we have a less significant route.
+	 * we've to insert an intermediate node on the list
+	 * this new node will point to the one we need to create
+	 * and the current
+	 */
+
+	pn = rcu_dereference_protected(fn->parent,
+				       lockdep_is_held(&table->tb6_lock));
+
+	/* find 1st bit in difference between the 2 addrs.
+
+	   See comment in __ipv6_addr_diff: bit may be an invalid value,
+	   but if it is >= plen, the value is ignored in any case.
+	 */
+
+	bit = __ipv6_addr_diff(addr, &key->addr, sizeof(*addr));
+
+	/*
+	 *		(intermediate)[in]
+	 *	          /	   \
+	 *	(new leaf node)[ln] (old node)[fn]
+	 */
+	if (plen > bit) {
+		in = node_alloc(net);
+		ln = node_alloc(net);
+
+		if (!in || !ln) {
+			if (in)
+				node_free_immediate(net, in);
+			if (ln)
+				node_free_immediate(net, ln);
+			return ERR_PTR(-ENOMEM);
+		}
+
+		/*
+		 * new intermediate node.
+		 * RTN_RTINFO will
+		 * be off since that an address that chooses one of
+		 * the branches would not match less specific routes
+		 * in the other branch
+		 */
+
+		in->fn_bit = bit;
+
+		RCU_INIT_POINTER(in->parent, pn);
+		in->leaf = fn->leaf;
+		atomic_inc(&rcu_dereference_protected(in->leaf,
+				lockdep_is_held(&table->tb6_lock))->fib6_ref);
+
+		/* update parent pointer */
+		if (dir)
+			rcu_assign_pointer(pn->right, in);
+		else
+			rcu_assign_pointer(pn->left, in);
+
+		ln->fn_bit = plen;
+
+		RCU_INIT_POINTER(ln->parent, in);
+		rcu_assign_pointer(fn->parent, in);
+
+		if (addr_bit_set(addr, bit)) {
+			rcu_assign_pointer(in->right, ln);
+			rcu_assign_pointer(in->left, fn);
+		} else {
+			rcu_assign_pointer(in->left, ln);
+			rcu_assign_pointer(in->right, fn);
+		}
+	} else { /* plen <= bit */
+
+		/*
+		 *		(new leaf node)[ln]
+		 *	          /	   \
+		 *	     (old node)[fn] NULL
+		 */
+
+		ln = node_alloc(net);
+
+		if (!ln)
+			return ERR_PTR(-ENOMEM);
+
+		ln->fn_bit = plen;
+
+		RCU_INIT_POINTER(ln->parent, pn);
+
+		if (addr_bit_set(&key->addr, plen))
+			RCU_INIT_POINTER(ln->right, fn);
+		else
+			RCU_INIT_POINTER(ln->left, fn);
+
+		rcu_assign_pointer(fn->parent, ln);
+
+		if (dir)
+			rcu_assign_pointer(pn->right, ln);
+		else
+			rcu_assign_pointer(pn->left, ln);
+	}
+	return ln;
+}
+
+static void fib6_drop_pcpu_from(struct fib6_info *f6i,
+				const struct fib6_table *table)
+{
+	int cpu;
+
+	/* Make sure rt6_make_pcpu_route() wont add other percpu routes
+	 * while we are cleaning them here.
+	 */
+	f6i->fib6_destroying = 1;
+	mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
+
+	/* release the reference to this fib entry from
+	 * all of its cached pcpu routes
+	 */
+	for_each_possible_cpu(cpu) {
+		struct rt6_info **ppcpu_rt;
+		struct rt6_info *pcpu_rt;
+
+		ppcpu_rt = per_cpu_ptr(f6i->rt6i_pcpu, cpu);
+		pcpu_rt = *ppcpu_rt;
+		if (pcpu_rt) {
+			struct fib6_info *from;
+
+			from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
+			fib6_info_release(from);
+		}
+	}
+}
+
+static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn,
+			  struct net *net)
+{
+	struct fib6_table *table = rt->fib6_table;
+
+	/* Flush all cached dst in exception table */
+	rt6_flush_exceptions(rt);
+	if (rt->rt6i_pcpu)
+		fib6_drop_pcpu_from(rt, table);
+
+	if (atomic_read(&rt->fib6_ref) != 1) {
+		/* This route is used as dummy address holder in some split
+		 * nodes. It is not leaked, but it still holds other resources,
+		 * which must be released in time. So, scan ascendant nodes
+		 * and replace dummy references to this route with references
+		 * to still alive ones.
+		 */
+		while (fn) {
+			struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
+					    lockdep_is_held(&table->tb6_lock));
+			struct fib6_info *new_leaf;
+			if (!(fn->fn_flags & RTN_RTINFO) && leaf == rt) {
+				new_leaf = fib6_find_prefix(net, table, fn);
+				atomic_inc(&new_leaf->fib6_ref);
+
+				rcu_assign_pointer(fn->leaf, new_leaf);
+				fib6_info_release(rt);
+			}
+			fn = rcu_dereference_protected(fn->parent,
+				    lockdep_is_held(&table->tb6_lock));
+		}
+	}
+}
+
+/*
+ *	Insert routing information in a node.
+ */
+
+static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
+			    struct nl_info *info,
+			    struct netlink_ext_ack *extack)
+{
+	struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,
+				    lockdep_is_held(&rt->fib6_table->tb6_lock));
+	struct fib6_info *iter = NULL;
+	struct fib6_info __rcu **ins;
+	struct fib6_info __rcu **fallback_ins = NULL;
+	int replace = (info->nlh &&
+		       (info->nlh->nlmsg_flags & NLM_F_REPLACE));
+	int add = (!info->nlh ||
+		   (info->nlh->nlmsg_flags & NLM_F_CREATE));
+	int found = 0;
+	bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
+	u16 nlflags = NLM_F_EXCL;
+	int err;
+
+	if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))
+		nlflags |= NLM_F_APPEND;
+
+	ins = &fn->leaf;
+
+	for (iter = leaf; iter;
+	     iter = rcu_dereference_protected(iter->fib6_next,
+				lockdep_is_held(&rt->fib6_table->tb6_lock))) {
+		/*
+		 *	Search for duplicates
+		 */
+
+		if (iter->fib6_metric == rt->fib6_metric) {
+			/*
+			 *	Same priority level
+			 */
+			if (info->nlh &&
+			    (info->nlh->nlmsg_flags & NLM_F_EXCL))
+				return -EEXIST;
+
+			nlflags &= ~NLM_F_EXCL;
+			if (replace) {
+				if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {
+					found++;
+					break;
+				}
+				fallback_ins = fallback_ins ?: ins;
+				goto next_iter;
+			}
+
+			if (rt6_duplicate_nexthop(iter, rt)) {
+				if (rt->fib6_nsiblings)
+					rt->fib6_nsiblings = 0;
+				if (!(iter->fib6_flags & RTF_EXPIRES))
+					return -EEXIST;
+				if (!(rt->fib6_flags & RTF_EXPIRES))
+					fib6_clean_expires(iter);
+				else
+					fib6_set_expires(iter, rt->expires);
+
+				if (rt->fib6_pmtu)
+					fib6_metric_set(iter, RTAX_MTU,
+							rt->fib6_pmtu);
+				return -EEXIST;
+			}
+			/* If we have the same destination and the same metric,
+			 * but not the same gateway, then the route we try to
+			 * add is sibling to this route, increment our counter
+			 * of siblings, and later we will add our route to the
+			 * list.
+			 * Only static routes (which don't have flag
+			 * RTF_EXPIRES) are used for ECMPv6.
+			 *
+			 * To avoid long list, we only had siblings if the
+			 * route have a gateway.
+			 */
+			if (rt_can_ecmp &&
+			    rt6_qualify_for_ecmp(iter))
+				rt->fib6_nsiblings++;
+		}
+
+		if (iter->fib6_metric > rt->fib6_metric)
+			break;
+
+next_iter:
+		ins = &iter->fib6_next;
+	}
+
+	if (fallback_ins && !found) {
+		/* No matching route with same ecmp-able-ness found, replace
+		 * first matching route
+		 */
+		ins = fallback_ins;
+		iter = rcu_dereference_protected(*ins,
+				    lockdep_is_held(&rt->fib6_table->tb6_lock));
+		found++;
+	}
+
+	/* Reset round-robin state, if necessary */
+	if (ins == &fn->leaf)
+		fn->rr_ptr = NULL;
+
+	/* Link this route to others same route. */
+	if (rt->fib6_nsiblings) {
+		unsigned int fib6_nsiblings;
+		struct fib6_info *sibling, *temp_sibling;
+
+		/* Find the first route that have the same metric */
+		sibling = leaf;
+		while (sibling) {
+			if (sibling->fib6_metric == rt->fib6_metric &&
+			    rt6_qualify_for_ecmp(sibling)) {
+				list_add_tail(&rt->fib6_siblings,
+					      &sibling->fib6_siblings);
+				break;
+			}
+			sibling = rcu_dereference_protected(sibling->fib6_next,
+				    lockdep_is_held(&rt->fib6_table->tb6_lock));
+		}
+		/* For each sibling in the list, increment the counter of
+		 * siblings. BUG() if counters does not match, list of siblings
+		 * is broken!
+		 */
+		fib6_nsiblings = 0;
+		list_for_each_entry_safe(sibling, temp_sibling,
+					 &rt->fib6_siblings, fib6_siblings) {
+			sibling->fib6_nsiblings++;
+			BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings);
+			fib6_nsiblings++;
+		}
+		BUG_ON(fib6_nsiblings != rt->fib6_nsiblings);
+		rt6_multipath_rebalance(temp_sibling);
+	}
+
+	/*
+	 *	insert node
+	 */
+	if (!replace) {
+		if (!add)
+			pr_warn("NLM_F_CREATE should be set when creating new route\n");
+
+add:
+		nlflags |= NLM_F_CREATE;
+
+		err = call_fib6_entry_notifiers(info->nl_net,
+						FIB_EVENT_ENTRY_ADD,
+						rt, extack);
+		if (err) {
+			struct fib6_info *sibling, *next_sibling;
+
+			/* If the route has siblings, then it first
+			 * needs to be unlinked from them.
+			 */
+			if (!rt->fib6_nsiblings)
+				return err;
+
+			list_for_each_entry_safe(sibling, next_sibling,
+						 &rt->fib6_siblings,
+						 fib6_siblings)
+				sibling->fib6_nsiblings--;
+			rt->fib6_nsiblings = 0;
+			list_del_init(&rt->fib6_siblings);
+			rt6_multipath_rebalance(next_sibling);
+			return err;
+		}
+
+		rcu_assign_pointer(rt->fib6_next, iter);
+		atomic_inc(&rt->fib6_ref);
+		rcu_assign_pointer(rt->fib6_node, fn);
+		rcu_assign_pointer(*ins, rt);
+		if (!info->skip_notify)
+			inet6_rt_notify(RTM_NEWROUTE, rt, info, nlflags);
+		info->nl_net->ipv6.rt6_stats->fib_rt_entries++;
+
+		if (!(fn->fn_flags & RTN_RTINFO)) {
+			info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
+			fn->fn_flags |= RTN_RTINFO;
+		}
+
+	} else {
+		int nsiblings;
+
+		if (!found) {
+			if (add)
+				goto add;
+			pr_warn("NLM_F_REPLACE set, but no existing node found!\n");
+			return -ENOENT;
+		}
+
+		err = call_fib6_entry_notifiers(info->nl_net,
+						FIB_EVENT_ENTRY_REPLACE,
+						rt, extack);
+		if (err)
+			return err;
+
+		atomic_inc(&rt->fib6_ref);
+		rcu_assign_pointer(rt->fib6_node, fn);
+		rt->fib6_next = iter->fib6_next;
+		rcu_assign_pointer(*ins, rt);
+		if (!info->skip_notify)
+			inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);
+		if (!(fn->fn_flags & RTN_RTINFO)) {
+			info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
+			fn->fn_flags |= RTN_RTINFO;
+		}
+		nsiblings = iter->fib6_nsiblings;
+		iter->fib6_node = NULL;
+		fib6_purge_rt(iter, fn, info->nl_net);
+		if (rcu_access_pointer(fn->rr_ptr) == iter)
+			fn->rr_ptr = NULL;
+		fib6_info_release(iter);
+
+		if (nsiblings) {
+			/* Replacing an ECMP route, remove all siblings */
+			ins = &rt->fib6_next;
+			iter = rcu_dereference_protected(*ins,
+				    lockdep_is_held(&rt->fib6_table->tb6_lock));
+			while (iter) {
+				if (iter->fib6_metric > rt->fib6_metric)
+					break;
+				if (rt6_qualify_for_ecmp(iter)) {
+					*ins = iter->fib6_next;
+					iter->fib6_node = NULL;
+					fib6_purge_rt(iter, fn, info->nl_net);
+					if (rcu_access_pointer(fn->rr_ptr) == iter)
+						fn->rr_ptr = NULL;
+					fib6_info_release(iter);
+					nsiblings--;
+					info->nl_net->ipv6.rt6_stats->fib_rt_entries--;
+				} else {
+					ins = &iter->fib6_next;
+				}
+				iter = rcu_dereference_protected(*ins,
+					lockdep_is_held(&rt->fib6_table->tb6_lock));
+			}
+			WARN_ON(nsiblings != 0);
+		}
+	}
+
+	return 0;
+}
+
+static void fib6_start_gc(struct net *net, struct fib6_info *rt)
+{
+	if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
+	    (rt->fib6_flags & RTF_EXPIRES))
+		mod_timer(&net->ipv6.ip6_fib_timer,
+			  jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
+}
+
+void fib6_force_start_gc(struct net *net)
+{
+	if (!timer_pending(&net->ipv6.ip6_fib_timer))
+		mod_timer(&net->ipv6.ip6_fib_timer,
+			  jiffies + net->ipv6.sysctl.ip6_rt_gc_interval);
+}
+
+static void __fib6_update_sernum_upto_root(struct fib6_info *rt,
+					   int sernum)
+{
+	struct fib6_node *fn = rcu_dereference_protected(rt->fib6_node,
+				lockdep_is_held(&rt->fib6_table->tb6_lock));
+
+	/* paired with smp_rmb() in rt6_get_cookie_safe() */
+	smp_wmb();
+	while (fn) {
+		WRITE_ONCE(fn->fn_sernum, sernum);
+		fn = rcu_dereference_protected(fn->parent,
+				lockdep_is_held(&rt->fib6_table->tb6_lock));
+	}
+}
+
+void fib6_update_sernum_upto_root(struct net *net, struct fib6_info *rt)
+{
+	__fib6_update_sernum_upto_root(rt, fib6_new_sernum(net));
+}
+
+/*
+ *	Add routing information to the routing tree.
+ *	<destination addr>/<source addr>
+ *	with source addr info in sub-trees
+ *	Need to own table->tb6_lock
+ */
+
+int fib6_add(struct fib6_node *root, struct fib6_info *rt,
+	     struct nl_info *info, struct netlink_ext_ack *extack)
+{
+	struct fib6_table *table = rt->fib6_table;
+	struct fib6_node *fn, *pn = NULL;
+	int err = -ENOMEM;
+	int allow_create = 1;
+	int replace_required = 0;
+	int sernum = fib6_new_sernum(info->nl_net);
+
+	if (info->nlh) {
+		if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
+			allow_create = 0;
+		if (info->nlh->nlmsg_flags & NLM_F_REPLACE)
+			replace_required = 1;
+	}
+	if (!allow_create && !replace_required)
+		pr_warn("RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n");
+
+	fn = fib6_add_1(info->nl_net, table, root,
+			&rt->fib6_dst.addr, rt->fib6_dst.plen,
+			offsetof(struct fib6_info, fib6_dst), allow_create,
+			replace_required, extack);
+	if (IS_ERR(fn)) {
+		err = PTR_ERR(fn);
+		fn = NULL;
+		goto out;
+	}
+
+	pn = fn;
+
+#ifdef CONFIG_IPV6_SUBTREES
+	if (rt->fib6_src.plen) {
+		struct fib6_node *sn;
+
+		if (!rcu_access_pointer(fn->subtree)) {
+			struct fib6_node *sfn;
+
+			/*
+			 * Create subtree.
+			 *
+			 *		fn[main tree]
+			 *		|
+			 *		sfn[subtree root]
+			 *		   \
+			 *		    sn[new leaf node]
+			 */
+
+			/* Create subtree root node */
+			sfn = node_alloc(info->nl_net);
+			if (!sfn)
+				goto failure;
+
+			atomic_inc(&info->nl_net->ipv6.fib6_null_entry->fib6_ref);
+			rcu_assign_pointer(sfn->leaf,
+					   info->nl_net->ipv6.fib6_null_entry);
+			sfn->fn_flags = RTN_ROOT;
+
+			/* Now add the first leaf node to new subtree */
+
+			sn = fib6_add_1(info->nl_net, table, sfn,
+					&rt->fib6_src.addr, rt->fib6_src.plen,
+					offsetof(struct fib6_info, fib6_src),
+					allow_create, replace_required, extack);
+
+			if (IS_ERR(sn)) {
+				/* If it is failed, discard just allocated
+				   root, and then (in failure) stale node
+				   in main tree.
+				 */
+				node_free_immediate(info->nl_net, sfn);
+				err = PTR_ERR(sn);
+				goto failure;
+			}
+
+			/* Now link new subtree to main tree */
+			rcu_assign_pointer(sfn->parent, fn);
+			rcu_assign_pointer(fn->subtree, sfn);
+		} else {
+			sn = fib6_add_1(info->nl_net, table, FIB6_SUBTREE(fn),
+					&rt->fib6_src.addr, rt->fib6_src.plen,
+					offsetof(struct fib6_info, fib6_src),
+					allow_create, replace_required, extack);
+
+			if (IS_ERR(sn)) {
+				err = PTR_ERR(sn);
+				goto failure;
+			}
+		}
+
+		if (!rcu_access_pointer(fn->leaf)) {
+			if (fn->fn_flags & RTN_TL_ROOT) {
+				/* put back null_entry for root node */
+				rcu_assign_pointer(fn->leaf,
+					    info->nl_net->ipv6.fib6_null_entry);
+			} else {
+				atomic_inc(&rt->fib6_ref);
+				rcu_assign_pointer(fn->leaf, rt);
+			}
+		}
+		fn = sn;
+	}
+#endif
+
+	err = fib6_add_rt2node(fn, rt, info, extack);
+	if (!err) {
+		__fib6_update_sernum_upto_root(rt, sernum);
+		fib6_start_gc(info->nl_net, rt);
+	}
+
+out:
+	if (err) {
+#ifdef CONFIG_IPV6_SUBTREES
+		/*
+		 * If fib6_add_1 has cleared the old leaf pointer in the
+		 * super-tree leaf node we have to find a new one for it.
+		 */
+		if (pn != fn) {
+			struct fib6_info *pn_leaf =
+				rcu_dereference_protected(pn->leaf,
+				    lockdep_is_held(&table->tb6_lock));
+			if (pn_leaf == rt) {
+				pn_leaf = NULL;
+				RCU_INIT_POINTER(pn->leaf, NULL);
+				fib6_info_release(rt);
+			}
+			if (!pn_leaf && !(pn->fn_flags & RTN_RTINFO)) {
+				pn_leaf = fib6_find_prefix(info->nl_net, table,
+							   pn);
+#if RT6_DEBUG >= 2
+				if (!pn_leaf) {
+					WARN_ON(!pn_leaf);
+					pn_leaf =
+					    info->nl_net->ipv6.fib6_null_entry;
+				}
+#endif
+				fib6_info_hold(pn_leaf);
+				rcu_assign_pointer(pn->leaf, pn_leaf);
+			}
+		}
+#endif
+		goto failure;
+	}
+	return err;
+
+failure:
+	/* fn->leaf could be NULL and fib6_repair_tree() needs to be called if:
+	 * 1. fn is an intermediate node and we failed to add the new
+	 * route to it in both subtree creation failure and fib6_add_rt2node()
+	 * failure case.
+	 * 2. fn is the root node in the table and we fail to add the first
+	 * default route to it.
+	 */
+	if (fn &&
+	    (!(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)) ||
+	     (fn->fn_flags & RTN_TL_ROOT &&
+	      !rcu_access_pointer(fn->leaf))))
+		fib6_repair_tree(info->nl_net, table, fn);
+	return err;
+}
+
+/*
+ *	Routing tree lookup
+ *
+ */
+
+struct lookup_args {
+	int			offset;		/* key offset on fib6_info */
+	const struct in6_addr	*addr;		/* search key			*/
+};
+
+static struct fib6_node *fib6_node_lookup_1(struct fib6_node *root,
+					    struct lookup_args *args)
+{
+	struct fib6_node *fn;
+	__be32 dir;
+
+	if (unlikely(args->offset == 0))
+		return NULL;
+
+	/*
+	 *	Descend on a tree
+	 */
+
+	fn = root;
+
+	for (;;) {
+		struct fib6_node *next;
+
+		dir = addr_bit_set(args->addr, fn->fn_bit);
+
+		next = dir ? rcu_dereference(fn->right) :
+			     rcu_dereference(fn->left);
+
+		if (next) {
+			fn = next;
+			continue;
+		}
+		break;
+	}
+
+	while (fn) {
+		struct fib6_node *subtree = FIB6_SUBTREE(fn);
+
+		if (subtree || fn->fn_flags & RTN_RTINFO) {
+			struct fib6_info *leaf = rcu_dereference(fn->leaf);
+			struct rt6key *key;
+
+			if (!leaf)
+				goto backtrack;
+
+			key = (struct rt6key *) ((u8 *)leaf + args->offset);
+
+			if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
+#ifdef CONFIG_IPV6_SUBTREES
+				if (subtree) {
+					struct fib6_node *sfn;
+					sfn = fib6_node_lookup_1(subtree,
+								 args + 1);
+					if (!sfn)
+						goto backtrack;
+					fn = sfn;
+				}
+#endif
+				if (fn->fn_flags & RTN_RTINFO)
+					return fn;
+			}
+		}
+backtrack:
+		if (fn->fn_flags & RTN_ROOT)
+			break;
+
+		fn = rcu_dereference(fn->parent);
+	}
+
+	return NULL;
+}
+
+/* called with rcu_read_lock() held
+ */
+struct fib6_node *fib6_node_lookup(struct fib6_node *root,
+				   const struct in6_addr *daddr,
+				   const struct in6_addr *saddr)
+{
+	struct fib6_node *fn;
+	struct lookup_args args[] = {
+		{
+			.offset = offsetof(struct fib6_info, fib6_dst),
+			.addr = daddr,
+		},
+#ifdef CONFIG_IPV6_SUBTREES
+		{
+			.offset = offsetof(struct fib6_info, fib6_src),
+			.addr = saddr,
+		},
+#endif
+		{
+			.offset = 0,	/* sentinel */
+		}
+	};
+
+	fn = fib6_node_lookup_1(root, daddr ? args : args + 1);
+	if (!fn || fn->fn_flags & RTN_TL_ROOT)
+		fn = root;
+
+	return fn;
+}
+
+/*
+ *	Get node with specified destination prefix (and source prefix,
+ *	if subtrees are used)
+ *	exact_match == true means we try to find fn with exact match of
+ *	the passed in prefix addr
+ *	exact_match == false means we try to find fn with longest prefix
+ *	match of the passed in prefix addr. This is useful for finding fn
+ *	for cached route as it will be stored in the exception table under
+ *	the node with longest prefix length.
+ */
+
+
+static struct fib6_node *fib6_locate_1(struct fib6_node *root,
+				       const struct in6_addr *addr,
+				       int plen, int offset,
+				       bool exact_match)
+{
+	struct fib6_node *fn, *prev = NULL;
+
+	for (fn = root; fn ; ) {
+		struct fib6_info *leaf = rcu_dereference(fn->leaf);
+		struct rt6key *key;
+
+		/* This node is being deleted */
+		if (!leaf) {
+			if (plen <= fn->fn_bit)
+				goto out;
+			else
+				goto next;
+		}
+
+		key = (struct rt6key *)((u8 *)leaf + offset);
+
+		/*
+		 *	Prefix match
+		 */
+		if (plen < fn->fn_bit ||
+		    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
+			goto out;
+
+		if (plen == fn->fn_bit)
+			return fn;
+
+		if (fn->fn_flags & RTN_RTINFO)
+			prev = fn;
+
+next:
+		/*
+		 *	We have more bits to go
+		 */
+		if (addr_bit_set(addr, fn->fn_bit))
+			fn = rcu_dereference(fn->right);
+		else
+			fn = rcu_dereference(fn->left);
+	}
+out:
+	if (exact_match)
+		return NULL;
+	else
+		return prev;
+}
+
+struct fib6_node *fib6_locate(struct fib6_node *root,
+			      const struct in6_addr *daddr, int dst_len,
+			      const struct in6_addr *saddr, int src_len,
+			      bool exact_match)
+{
+	struct fib6_node *fn;
+
+	fn = fib6_locate_1(root, daddr, dst_len,
+			   offsetof(struct fib6_info, fib6_dst),
+			   exact_match);
+
+#ifdef CONFIG_IPV6_SUBTREES
+	if (src_len) {
+		WARN_ON(saddr == NULL);
+		if (fn) {
+			struct fib6_node *subtree = FIB6_SUBTREE(fn);
+
+			if (subtree) {
+				fn = fib6_locate_1(subtree, saddr, src_len,
+					   offsetof(struct fib6_info, fib6_src),
+					   exact_match);
+			}
+		}
+	}
+#endif
+
+	if (fn && fn->fn_flags & RTN_RTINFO)
+		return fn;
+
+	return NULL;
+}
+
+
+/*
+ *	Deletion
+ *
+ */
+
+static struct fib6_info *fib6_find_prefix(struct net *net,
+					 struct fib6_table *table,
+					 struct fib6_node *fn)
+{
+	struct fib6_node *child_left, *child_right;
+
+	if (fn->fn_flags & RTN_ROOT)
+		return net->ipv6.fib6_null_entry;
+
+	while (fn) {
+		child_left = rcu_dereference_protected(fn->left,
+				    lockdep_is_held(&table->tb6_lock));
+		child_right = rcu_dereference_protected(fn->right,
+				    lockdep_is_held(&table->tb6_lock));
+		if (child_left)
+			return rcu_dereference_protected(child_left->leaf,
+					lockdep_is_held(&table->tb6_lock));
+		if (child_right)
+			return rcu_dereference_protected(child_right->leaf,
+					lockdep_is_held(&table->tb6_lock));
+
+		fn = FIB6_SUBTREE(fn);
+	}
+	return NULL;
+}
+
+/*
+ *	Called to trim the tree of intermediate nodes when possible. "fn"
+ *	is the node we want to try and remove.
+ *	Need to own table->tb6_lock
+ */
+
+static struct fib6_node *fib6_repair_tree(struct net *net,
+					  struct fib6_table *table,
+					  struct fib6_node *fn)
+{
+	int children;
+	int nstate;
+	struct fib6_node *child;
+	struct fib6_walker *w;
+	int iter = 0;
+
+	/* Set fn->leaf to null_entry for root node. */
+	if (fn->fn_flags & RTN_TL_ROOT) {
+		rcu_assign_pointer(fn->leaf, net->ipv6.fib6_null_entry);
+		return fn;
+	}
+
+	for (;;) {
+		struct fib6_node *fn_r = rcu_dereference_protected(fn->right,
+					    lockdep_is_held(&table->tb6_lock));
+		struct fib6_node *fn_l = rcu_dereference_protected(fn->left,
+					    lockdep_is_held(&table->tb6_lock));
+		struct fib6_node *pn = rcu_dereference_protected(fn->parent,
+					    lockdep_is_held(&table->tb6_lock));
+		struct fib6_node *pn_r = rcu_dereference_protected(pn->right,
+					    lockdep_is_held(&table->tb6_lock));
+		struct fib6_node *pn_l = rcu_dereference_protected(pn->left,
+					    lockdep_is_held(&table->tb6_lock));
+		struct fib6_info *fn_leaf = rcu_dereference_protected(fn->leaf,
+					    lockdep_is_held(&table->tb6_lock));
+		struct fib6_info *pn_leaf = rcu_dereference_protected(pn->leaf,
+					    lockdep_is_held(&table->tb6_lock));
+		struct fib6_info *new_fn_leaf;
+
+		RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
+		iter++;
+
+		WARN_ON(fn->fn_flags & RTN_RTINFO);
+		WARN_ON(fn->fn_flags & RTN_TL_ROOT);
+		WARN_ON(fn_leaf);
+
+		children = 0;
+		child = NULL;
+		if (fn_r)
+			child = fn_r, children |= 1;
+		if (fn_l)
+			child = fn_l, children |= 2;
+
+		if (children == 3 || FIB6_SUBTREE(fn)
+#ifdef CONFIG_IPV6_SUBTREES
+		    /* Subtree root (i.e. fn) may have one child */
+		    || (children && fn->fn_flags & RTN_ROOT)
+#endif
+		    ) {
+			new_fn_leaf = fib6_find_prefix(net, table, fn);
+#if RT6_DEBUG >= 2
+			if (!new_fn_leaf) {
+				WARN_ON(!new_fn_leaf);
+				new_fn_leaf = net->ipv6.fib6_null_entry;
+			}
+#endif
+			fib6_info_hold(new_fn_leaf);
+			rcu_assign_pointer(fn->leaf, new_fn_leaf);
+			return pn;
+		}
+
+#ifdef CONFIG_IPV6_SUBTREES
+		if (FIB6_SUBTREE(pn) == fn) {
+			WARN_ON(!(fn->fn_flags & RTN_ROOT));
+			RCU_INIT_POINTER(pn->subtree, NULL);
+			nstate = FWS_L;
+		} else {
+			WARN_ON(fn->fn_flags & RTN_ROOT);
+#endif
+			if (pn_r == fn)
+				rcu_assign_pointer(pn->right, child);
+			else if (pn_l == fn)
+				rcu_assign_pointer(pn->left, child);
+#if RT6_DEBUG >= 2
+			else
+				WARN_ON(1);
+#endif
+			if (child)
+				rcu_assign_pointer(child->parent, pn);
+			nstate = FWS_R;
+#ifdef CONFIG_IPV6_SUBTREES
+		}
+#endif
+
+		read_lock(&net->ipv6.fib6_walker_lock);
+		FOR_WALKERS(net, w) {
+			if (!child) {
+				if (w->node == fn) {
+					RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
+					w->node = pn;
+					w->state = nstate;
+				}
+			} else {
+				if (w->node == fn) {
+					w->node = child;
+					if (children&2) {
+						RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
+						w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
+					} else {
+						RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
+						w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
+					}
+				}
+			}
+		}
+		read_unlock(&net->ipv6.fib6_walker_lock);
+
+		node_free(net, fn);
+		if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
+			return pn;
+
+		RCU_INIT_POINTER(pn->leaf, NULL);
+		fib6_info_release(pn_leaf);
+		fn = pn;
+	}
+}
+
+static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
+			   struct fib6_info __rcu **rtp, struct nl_info *info)
+{
+	struct fib6_walker *w;
+	struct fib6_info *rt = rcu_dereference_protected(*rtp,
+				    lockdep_is_held(&table->tb6_lock));
+	struct net *net = info->nl_net;
+
+	RT6_TRACE("fib6_del_route\n");
+
+	/* Unlink it */
+	*rtp = rt->fib6_next;
+	rt->fib6_node = NULL;
+	net->ipv6.rt6_stats->fib_rt_entries--;
+	net->ipv6.rt6_stats->fib_discarded_routes++;
+
+	/* Reset round-robin state, if necessary */
+	if (rcu_access_pointer(fn->rr_ptr) == rt)
+		fn->rr_ptr = NULL;
+
+	/* Remove this entry from other siblings */
+	if (rt->fib6_nsiblings) {
+		struct fib6_info *sibling, *next_sibling;
+
+		list_for_each_entry_safe(sibling, next_sibling,
+					 &rt->fib6_siblings, fib6_siblings)
+			sibling->fib6_nsiblings--;
+		rt->fib6_nsiblings = 0;
+		list_del_init(&rt->fib6_siblings);
+		rt6_multipath_rebalance(next_sibling);
+	}
+
+	/* Adjust walkers */
+	read_lock(&net->ipv6.fib6_walker_lock);
+	FOR_WALKERS(net, w) {
+		if (w->state == FWS_C && w->leaf == rt) {
+			RT6_TRACE("walker %p adjusted by delroute\n", w);
+			w->leaf = rcu_dereference_protected(rt->fib6_next,
+					    lockdep_is_held(&table->tb6_lock));
+			if (!w->leaf)
+				w->state = FWS_U;
+		}
+	}
+	read_unlock(&net->ipv6.fib6_walker_lock);
+
+	/* If it was last route, call fib6_repair_tree() to:
+	 * 1. For root node, put back null_entry as how the table was created.
+	 * 2. For other nodes, expunge its radix tree node.
+	 */
+	if (!rcu_access_pointer(fn->leaf)) {
+		if (!(fn->fn_flags & RTN_TL_ROOT)) {
+			fn->fn_flags &= ~RTN_RTINFO;
+			net->ipv6.rt6_stats->fib_route_nodes--;
+		}
+		fn = fib6_repair_tree(net, table, fn);
+	}
+
+	fib6_purge_rt(rt, fn, net);
+
+	call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, rt, NULL);
+	if (!info->skip_notify)
+		inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
+	fib6_info_release(rt);
+}
+
+/* Need to own table->tb6_lock */
+int fib6_del(struct fib6_info *rt, struct nl_info *info)
+{
+	struct net *net = info->nl_net;
+	struct fib6_info __rcu **rtp;
+	struct fib6_info __rcu **rtp_next;
+	struct fib6_table *table;
+	struct fib6_node *fn;
+
+	if (rt == net->ipv6.fib6_null_entry)
+		return -ENOENT;
+
+	table = rt->fib6_table;
+	fn = rcu_dereference_protected(rt->fib6_node,
+				       lockdep_is_held(&table->tb6_lock));
+	if (!fn)
+		return -ENOENT;
+
+	WARN_ON(!(fn->fn_flags & RTN_RTINFO));
+
+	/*
+	 *	Walk the leaf entries looking for ourself
+	 */
+
+	for (rtp = &fn->leaf; *rtp; rtp = rtp_next) {
+		struct fib6_info *cur = rcu_dereference_protected(*rtp,
+					lockdep_is_held(&table->tb6_lock));
+		if (rt == cur) {
+			fib6_del_route(table, fn, rtp, info);
+			return 0;
+		}
+		rtp_next = &cur->fib6_next;
+	}
+	return -ENOENT;
+}
+
+/*
+ *	Tree traversal function.
+ *
+ *	Certainly, it is not interrupt safe.
+ *	However, it is internally reenterable wrt itself and fib6_add/fib6_del.
+ *	It means, that we can modify tree during walking
+ *	and use this function for garbage collection, clone pruning,
+ *	cleaning tree when a device goes down etc. etc.
+ *
+ *	It guarantees that every node will be traversed,
+ *	and that it will be traversed only once.
+ *
+ *	Callback function w->func may return:
+ *	0 -> continue walking.
+ *	positive value -> walking is suspended (used by tree dumps,
+ *	and probably by gc, if it will be split to several slices)
+ *	negative value -> terminate walking.
+ *
+ *	The function itself returns:
+ *	0   -> walk is complete.
+ *	>0  -> walk is incomplete (i.e. suspended)
+ *	<0  -> walk is terminated by an error.
+ *
+ *	This function is called with tb6_lock held.
+ */
+
+static int fib6_walk_continue(struct fib6_walker *w)
+{
+	struct fib6_node *fn, *pn, *left, *right;
+
+	/* w->root should always be table->tb6_root */
+	WARN_ON_ONCE(!(w->root->fn_flags & RTN_TL_ROOT));
+
+	for (;;) {
+		fn = w->node;
+		if (!fn)
+			return 0;
+
+		switch (w->state) {
+#ifdef CONFIG_IPV6_SUBTREES
+		case FWS_S:
+			if (FIB6_SUBTREE(fn)) {
+				w->node = FIB6_SUBTREE(fn);
+				continue;
+			}
+			w->state = FWS_L;
+#endif
+			/* fall through */
+		case FWS_L:
+			left = rcu_dereference_protected(fn->left, 1);
+			if (left) {
+				w->node = left;
+				w->state = FWS_INIT;
+				continue;
+			}
+			w->state = FWS_R;
+			/* fall through */
+		case FWS_R:
+			right = rcu_dereference_protected(fn->right, 1);
+			if (right) {
+				w->node = right;
+				w->state = FWS_INIT;
+				continue;
+			}
+			w->state = FWS_C;
+			w->leaf = rcu_dereference_protected(fn->leaf, 1);
+			/* fall through */
+		case FWS_C:
+			if (w->leaf && fn->fn_flags & RTN_RTINFO) {
+				int err;
+
+				if (w->skip) {
+					w->skip--;
+					goto skip;
+				}
+
+				err = w->func(w);
+				if (err)
+					return err;
+
+				w->count++;
+				continue;
+			}
+skip:
+			w->state = FWS_U;
+			/* fall through */
+		case FWS_U:
+			if (fn == w->root)
+				return 0;
+			pn = rcu_dereference_protected(fn->parent, 1);
+			left = rcu_dereference_protected(pn->left, 1);
+			right = rcu_dereference_protected(pn->right, 1);
+			w->node = pn;
+#ifdef CONFIG_IPV6_SUBTREES
+			if (FIB6_SUBTREE(pn) == fn) {
+				WARN_ON(!(fn->fn_flags & RTN_ROOT));
+				w->state = FWS_L;
+				continue;
+			}
+#endif
+			if (left == fn) {
+				w->state = FWS_R;
+				continue;
+			}
+			if (right == fn) {
+				w->state = FWS_C;
+				w->leaf = rcu_dereference_protected(w->node->leaf, 1);
+				continue;
+			}
+#if RT6_DEBUG >= 2
+			WARN_ON(1);
+#endif
+		}
+	}
+}
+
+static int fib6_walk(struct net *net, struct fib6_walker *w)
+{
+	int res;
+
+	w->state = FWS_INIT;
+	w->node = w->root;
+
+	fib6_walker_link(net, w);
+	res = fib6_walk_continue(w);
+	if (res <= 0)
+		fib6_walker_unlink(net, w);
+	return res;
+}
+
+static int fib6_clean_node(struct fib6_walker *w)
+{
+	int res;
+	struct fib6_info *rt;
+	struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
+	struct nl_info info = {
+		.nl_net = c->net,
+	};
+
+	if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
+	    READ_ONCE(w->node->fn_sernum) != c->sernum)
+		WRITE_ONCE(w->node->fn_sernum, c->sernum);
+
+	if (!c->func) {
+		WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
+		w->leaf = NULL;
+		return 0;
+	}
+
+	for_each_fib6_walker_rt(w) {
+		res = c->func(rt, c->arg);
+		if (res == -1) {
+			w->leaf = rt;
+			res = fib6_del(rt, &info);
+			if (res) {
+#if RT6_DEBUG >= 2
+				pr_debug("%s: del failed: rt=%p@%p err=%d\n",
+					 __func__, rt,
+					 rcu_access_pointer(rt->fib6_node),
+					 res);
+#endif
+				continue;
+			}
+			return 0;
+		} else if (res == -2) {
+			if (WARN_ON(!rt->fib6_nsiblings))
+				continue;
+			rt = list_last_entry(&rt->fib6_siblings,
+					     struct fib6_info, fib6_siblings);
+			continue;
+		}
+		WARN_ON(res != 0);
+	}
+	w->leaf = rt;
+	return 0;
+}
+
+/*
+ *	Convenient frontend to tree walker.
+ *
+ *	func is called on each route.
+ *		It may return -2 -> skip multipath route.
+ *			      -1 -> delete this route.
+ *		              0  -> continue walking
+ */
+
+static void fib6_clean_tree(struct net *net, struct fib6_node *root,
+			    int (*func)(struct fib6_info *, void *arg),
+			    int sernum, void *arg)
+{
+	struct fib6_cleaner c;
+
+	c.w.root = root;
+	c.w.func = fib6_clean_node;
+	c.w.count = 0;
+	c.w.skip = 0;
+	c.func = func;
+	c.sernum = sernum;
+	c.arg = arg;
+	c.net = net;
+
+	fib6_walk(net, &c.w);
+}
+
+static void __fib6_clean_all(struct net *net,
+			     int (*func)(struct fib6_info *, void *),
+			     int sernum, void *arg)
+{
+	struct fib6_table *table;
+	struct hlist_head *head;
+	unsigned int h;
+
+	rcu_read_lock();
+	for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
+		head = &net->ipv6.fib_table_hash[h];
+		hlist_for_each_entry_rcu(table, head, tb6_hlist) {
+			spin_lock_bh(&table->tb6_lock);
+			fib6_clean_tree(net, &table->tb6_root,
+					func, sernum, arg);
+			spin_unlock_bh(&table->tb6_lock);
+		}
+	}
+	rcu_read_unlock();
+}
+
+void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *),
+		    void *arg)
+{
+	__fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
+}
+
+static void fib6_flush_trees(struct net *net)
+{
+	int new_sernum = fib6_new_sernum(net);
+
+	__fib6_clean_all(net, NULL, new_sernum, NULL);
+}
+
+/*
+ *	Garbage collection
+ */
+
+static int fib6_age(struct fib6_info *rt, void *arg)
+{
+	struct fib6_gc_args *gc_args = arg;
+	unsigned long now = jiffies;
+
+	/*
+	 *	check addrconf expiration here.
+	 *	Routes are expired even if they are in use.
+	 */
+
+	if (rt->fib6_flags & RTF_EXPIRES && rt->expires) {
+		if (time_after(now, rt->expires)) {
+			RT6_TRACE("expiring %p\n", rt);
+			return -1;
+		}
+		gc_args->more++;
+	}
+
+	/*	Also age clones in the exception table.
+	 *	Note, that clones are aged out
+	 *	only if they are not in use now.
+	 */
+	rt6_age_exceptions(rt, gc_args, now);
+
+	return 0;
+}
+
+void fib6_run_gc(unsigned long expires, struct net *net, bool force)
+{
+	struct fib6_gc_args gc_args;
+	unsigned long now;
+
+	if (force) {
+		spin_lock_bh(&net->ipv6.fib6_gc_lock);
+	} else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {
+		mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);
+		return;
+	}
+	gc_args.timeout = expires ? (int)expires :
+			  net->ipv6.sysctl.ip6_rt_gc_interval;
+	gc_args.more = 0;
+
+	fib6_clean_all(net, fib6_age, &gc_args);
+	now = jiffies;
+	net->ipv6.ip6_rt_last_gc = now;
+
+	if (gc_args.more)
+		mod_timer(&net->ipv6.ip6_fib_timer,
+			  round_jiffies(now
+					+ net->ipv6.sysctl.ip6_rt_gc_interval));
+	else
+		del_timer(&net->ipv6.ip6_fib_timer);
+	spin_unlock_bh(&net->ipv6.fib6_gc_lock);
+}
+
+static void fib6_gc_timer_cb(struct timer_list *t)
+{
+	struct net *arg = from_timer(arg, t, ipv6.ip6_fib_timer);
+
+	fib6_run_gc(0, arg, true);
+}
+
+static int __net_init fib6_net_init(struct net *net)
+{
+	size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;
+	int err;
+
+	err = fib6_notifier_init(net);
+	if (err)
+		return err;
+
+	spin_lock_init(&net->ipv6.fib6_gc_lock);
+	rwlock_init(&net->ipv6.fib6_walker_lock);
+	INIT_LIST_HEAD(&net->ipv6.fib6_walkers);
+	timer_setup(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, 0);
+
+	net->ipv6.rt6_stats = kzalloc(sizeof(*net->ipv6.rt6_stats), GFP_KERNEL);
+	if (!net->ipv6.rt6_stats)
+		goto out_timer;
+
+	/* Avoid false sharing : Use at least a full cache line */
+	size = max_t(size_t, size, L1_CACHE_BYTES);
+
+	net->ipv6.fib_table_hash = kzalloc(size, GFP_KERNEL);
+	if (!net->ipv6.fib_table_hash)
+		goto out_rt6_stats;
+
+	net->ipv6.fib6_main_tbl = kzalloc(sizeof(*net->ipv6.fib6_main_tbl),
+					  GFP_KERNEL);
+	if (!net->ipv6.fib6_main_tbl)
+		goto out_fib_table_hash;
+
+	net->ipv6.fib6_main_tbl->tb6_id = RT6_TABLE_MAIN;
+	rcu_assign_pointer(net->ipv6.fib6_main_tbl->tb6_root.leaf,
+			   net->ipv6.fib6_null_entry);
+	net->ipv6.fib6_main_tbl->tb6_root.fn_flags =
+		RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
+	inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);
+
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
+	net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
+					   GFP_KERNEL);
+	if (!net->ipv6.fib6_local_tbl)
+		goto out_fib6_main_tbl;
+	net->ipv6.fib6_local_tbl->tb6_id = RT6_TABLE_LOCAL;
+	rcu_assign_pointer(net->ipv6.fib6_local_tbl->tb6_root.leaf,
+			   net->ipv6.fib6_null_entry);
+	net->ipv6.fib6_local_tbl->tb6_root.fn_flags =
+		RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
+	inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);
+#endif
+	fib6_tables_init(net);
+
+	return 0;
+
+#ifdef CONFIG_IPV6_MULTIPLE_TABLES
+out_fib6_main_tbl:
+	kfree(net->ipv6.fib6_main_tbl);
+#endif
+out_fib_table_hash:
+	kfree(net->ipv6.fib_table_hash);
+out_rt6_stats:
+	kfree(net->ipv6.rt6_stats);
+out_timer:
+	fib6_notifier_exit(net);
+	return -ENOMEM;
+}
+
+static void fib6_net_exit(struct net *net)
+{
+	unsigned int i;
+
+	del_timer_sync(&net->ipv6.ip6_fib_timer);
+
+	for (i = 0; i < FIB6_TABLE_HASHSZ; i++) {
+		struct hlist_head *head = &net->ipv6.fib_table_hash[i];
+		struct hlist_node *tmp;
+		struct fib6_table *tb;
+
+		hlist_for_each_entry_safe(tb, tmp, head, tb6_hlist) {
+			hlist_del(&tb->tb6_hlist);
+			fib6_free_table(tb);
+		}
+	}
+
+	kfree(net->ipv6.fib_table_hash);
+	kfree(net->ipv6.rt6_stats);
+	fib6_notifier_exit(net);
+}
+
+static struct pernet_operations fib6_net_ops = {
+	.init = fib6_net_init,
+	.exit = fib6_net_exit,
+};
+
+int __init fib6_init(void)
+{
+	int ret = -ENOMEM;
+
+	fib6_node_kmem = kmem_cache_create("fib6_nodes",
+					   sizeof(struct fib6_node),
+					   0, SLAB_HWCACHE_ALIGN,
+					   NULL);
+	if (!fib6_node_kmem)
+		goto out;
+
+	ret = register_pernet_subsys(&fib6_net_ops);
+	if (ret)
+		goto out_kmem_cache_create;
+
+	ret = rtnl_register_module(THIS_MODULE, PF_INET6, RTM_GETROUTE, NULL,
+				   inet6_dump_fib, 0);
+	if (ret)
+		goto out_unregister_subsys;
+
+	__fib6_flush_trees = fib6_flush_trees;
+out:
+	return ret;
+
+out_unregister_subsys:
+	unregister_pernet_subsys(&fib6_net_ops);
+out_kmem_cache_create:
+	kmem_cache_destroy(fib6_node_kmem);
+	goto out;
+}
+
+void fib6_gc_cleanup(void)
+{
+	unregister_pernet_subsys(&fib6_net_ops);
+	kmem_cache_destroy(fib6_node_kmem);
+}
+
+#ifdef CONFIG_PROC_FS
+static int ipv6_route_seq_show(struct seq_file *seq, void *v)
+{
+	struct fib6_info *rt = v;
+	struct ipv6_route_iter *iter = seq->private;
+	const struct net_device *dev;
+
+	seq_printf(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen);
+
+#ifdef CONFIG_IPV6_SUBTREES
+	seq_printf(seq, "%pi6 %02x ", &rt->fib6_src.addr, rt->fib6_src.plen);
+#else
+	seq_puts(seq, "00000000000000000000000000000000 00 ");
+#endif
+	if (rt->fib6_flags & RTF_GATEWAY)
+		seq_printf(seq, "%pi6", &rt->fib6_nh.nh_gw);
+	else
+		seq_puts(seq, "00000000000000000000000000000000");
+
+	dev = rt->fib6_nh.nh_dev;
+	seq_printf(seq, " %08x %08x %08x %08x %8s\n",
+		   rt->fib6_metric, atomic_read(&rt->fib6_ref), 0,
+		   rt->fib6_flags, dev ? dev->name : "");
+	iter->w.leaf = NULL;
+	return 0;
+}
+
+static int ipv6_route_yield(struct fib6_walker *w)
+{
+	struct ipv6_route_iter *iter = w->args;
+
+	if (!iter->skip)
+		return 1;
+
+	do {
+		iter->w.leaf = rcu_dereference_protected(
+				iter->w.leaf->fib6_next,
+				lockdep_is_held(&iter->tbl->tb6_lock));
+		iter->skip--;
+		if (!iter->skip && iter->w.leaf)
+			return 1;
+	} while (iter->w.leaf);
+
+	return 0;
+}
+
+static void ipv6_route_seq_setup_walk(struct ipv6_route_iter *iter,
+				      struct net *net)
+{
+	memset(&iter->w, 0, sizeof(iter->w));
+	iter->w.func = ipv6_route_yield;
+	iter->w.root = &iter->tbl->tb6_root;
+	iter->w.state = FWS_INIT;
+	iter->w.node = iter->w.root;
+	iter->w.args = iter;
+	iter->sernum = READ_ONCE(iter->w.root->fn_sernum);
+	INIT_LIST_HEAD(&iter->w.lh);
+	fib6_walker_link(net, &iter->w);
+}
+
+static struct fib6_table *ipv6_route_seq_next_table(struct fib6_table *tbl,
+						    struct net *net)
+{
+	unsigned int h;
+	struct hlist_node *node;
+
+	if (tbl) {
+		h = (tbl->tb6_id & (FIB6_TABLE_HASHSZ - 1)) + 1;
+		node = rcu_dereference_bh(hlist_next_rcu(&tbl->tb6_hlist));
+	} else {
+		h = 0;
+		node = NULL;
+	}
+
+	while (!node && h < FIB6_TABLE_HASHSZ) {
+		node = rcu_dereference_bh(
+			hlist_first_rcu(&net->ipv6.fib_table_hash[h++]));
+	}
+	return hlist_entry_safe(node, struct fib6_table, tb6_hlist);
+}
+
+static void ipv6_route_check_sernum(struct ipv6_route_iter *iter)
+{
+	int sernum = READ_ONCE(iter->w.root->fn_sernum);
+
+	if (iter->sernum != sernum) {
+		iter->sernum = sernum;
+		iter->w.state = FWS_INIT;
+		iter->w.node = iter->w.root;
+		WARN_ON(iter->w.skip);
+		iter->w.skip = iter->w.count;
+	}
+}
+
+static void *ipv6_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	int r;
+	struct fib6_info *n;
+	struct net *net = seq_file_net(seq);
+	struct ipv6_route_iter *iter = seq->private;
+
+	++(*pos);
+	if (!v)
+		goto iter_table;
+
+	n = rcu_dereference_bh(((struct fib6_info *)v)->fib6_next);
+	if (n)
+		return n;
+
+iter_table:
+	ipv6_route_check_sernum(iter);
+	spin_lock_bh(&iter->tbl->tb6_lock);
+	r = fib6_walk_continue(&iter->w);
+	spin_unlock_bh(&iter->tbl->tb6_lock);
+	if (r > 0) {
+		return iter->w.leaf;
+	} else if (r < 0) {
+		fib6_walker_unlink(net, &iter->w);
+		return NULL;
+	}
+	fib6_walker_unlink(net, &iter->w);
+
+	iter->tbl = ipv6_route_seq_next_table(iter->tbl, net);
+	if (!iter->tbl)
+		return NULL;
+
+	ipv6_route_seq_setup_walk(iter, net);
+	goto iter_table;
+}
+
+static void *ipv6_route_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU_BH)
+{
+	struct net *net = seq_file_net(seq);
+	struct ipv6_route_iter *iter = seq->private;
+
+	rcu_read_lock_bh();
+	iter->tbl = ipv6_route_seq_next_table(NULL, net);
+	iter->skip = *pos;
+
+	if (iter->tbl) {
+		loff_t p = 0;
+
+		ipv6_route_seq_setup_walk(iter, net);
+		return ipv6_route_seq_next(seq, NULL, &p);
+	} else {
+		return NULL;
+	}
+}
+
+static bool ipv6_route_iter_active(struct ipv6_route_iter *iter)
+{
+	struct fib6_walker *w = &iter->w;
+	return w->node && !(w->state == FWS_U && w->node == w->root);
+}
+
+static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
+	__releases(RCU_BH)
+{
+	struct net *net = seq_file_net(seq);
+	struct ipv6_route_iter *iter = seq->private;
+
+	if (ipv6_route_iter_active(iter))
+		fib6_walker_unlink(net, &iter->w);
+
+	rcu_read_unlock_bh();
+}
+
+const struct seq_operations ipv6_route_seq_ops = {
+	.start	= ipv6_route_seq_start,
+	.next	= ipv6_route_seq_next,
+	.stop	= ipv6_route_seq_stop,
+	.show	= ipv6_route_seq_show
+};
+#endif /* CONFIG_PROC_FS */