[Feature]add MT2731_MP2_MR2_SVN388 baseline version

Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/net/ipv6/ip6_fib.c b/src/kernel/linux/v4.14/net/ipv6/ip6_fib.c
new file mode 100644
index 0000000..d43abeb
--- /dev/null
+++ b/src/kernel/linux/v4.14/net/ipv6/ip6_fib.c
@@ -0,0 +1,2281 @@
+/*
+ *	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>
+
+#define RT6_DEBUG 2
+
+#if RT6_DEBUG >= 3
+#define RT6_TRACE(x...) pr_debug(x)
+#else
+#define RT6_TRACE(x...) do { ; } while (0)
+#endif
+
+static struct kmem_cache *fib6_node_kmem __read_mostly;
+
+struct fib6_cleaner {
+	struct fib6_walker w;
+	struct net *net;
+	int (*func)(struct rt6_info *, void *arg);
+	int sernum;
+	void *arg;
+};
+
+#ifdef CONFIG_IPV6_SUBTREES
+#define FWS_INIT FWS_S
+#else
+#define FWS_INIT FWS_L
+#endif
+
+static void fib6_prune_clones(struct net *net, struct fib6_node *fn);
+static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn);
+static struct fib6_node *fib6_repair_tree(struct net *net, 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(unsigned long arg);
+
+#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,
+};
+
+/*
+ *	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];
+}
+
+static struct fib6_node *node_alloc(void)
+{
+	struct fib6_node *fn;
+
+	fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
+
+	return fn;
+}
+
+static void node_free_immediate(struct fib6_node *fn)
+{
+	kmem_cache_free(fib6_node_kmem, fn);
+}
+
+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 fib6_node *fn)
+{
+	call_rcu(&fn->rcu, node_free_rcu);
+}
+
+void rt6_free_pcpu(struct rt6_info *non_pcpu_rt)
+{
+	int cpu;
+
+	if (!non_pcpu_rt->rt6i_pcpu)
+		return;
+
+	for_each_possible_cpu(cpu) {
+		struct rt6_info **ppcpu_rt;
+		struct rt6_info *pcpu_rt;
+
+		ppcpu_rt = per_cpu_ptr(non_pcpu_rt->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(non_pcpu_rt->rt6i_pcpu);
+	non_pcpu_rt->rt6i_pcpu = NULL;
+}
+EXPORT_SYMBOL_GPL(rt6_free_pcpu);
+
+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.
+	 */
+	rwlock_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;
+		table->tb6_root.leaf = net->ipv6.ip6_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,
+				   int flags, pol_lookup_t lookup)
+{
+	struct rt6_info *rt;
+
+	rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, flags);
+	if (rt->dst.error == -EAGAIN) {
+		ip6_rt_put(rt);
+		rt = net->ipv6.ip6_null_entry;
+		dst_hold(&rt->dst);
+	}
+
+	return &rt->dst;
+}
+
+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) {
+			read_lock_bh(&tb->tb6_lock);
+			fib_seq += tb->fib_seq;
+			read_unlock_bh(&tb->tb6_lock);
+		}
+	}
+	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 rt6_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 rt6_info *rt)
+{
+	struct fib6_entry_notifier_info info = {
+		.rt = rt,
+	};
+
+	rt->rt6i_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 rt6_info *rt, struct fib6_dump_arg *arg)
+{
+	if (rt == arg->net->ipv6.ip6_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 rt6_info *rt;
+
+	for (rt = w->leaf; rt; rt = rt->dst.rt6_next)
+		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;
+	read_lock_bh(&tb->tb6_lock);
+	fib6_walk(net, w);
+	read_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 rt6_info *rt;
+
+	for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
+		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->rt6i_nsiblings)
+			rt = list_last_entry(&rt->rt6i_siblings,
+					     struct rt6_info,
+					     rt6i_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;
+
+		read_lock_bh(&table->tb6_lock);
+		res = fib6_walk(net, w);
+		read_unlock_bh(&table->tb6_lock);
+		if (res > 0) {
+			cb->args[4] = 1;
+			cb->args[5] = w->root->fn_sernum;
+		}
+	} else {
+		if (cb->args[5] != w->root->fn_sernum) {
+			/* Begin at the root if the tree changed */
+			cb->args[5] = w->root->fn_sernum;
+			w->state = FWS_INIT;
+			w->node = w->root;
+			w->skip = w->count;
+		} else
+			w->skip = 0;
+
+		read_lock_bh(&table->tb6_lock);
+		res = fib6_walk_continue(w);
+		read_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;
+}
+
+/*
+ *	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 fib6_node *root,
+				     struct in6_addr *addr, int plen,
+				     int offset, int allow_create,
+				     int replace_required, int sernum,
+				     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 {
+		key = (struct rt6key *)((u8 *)fn->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)) {
+				rt6_release(fn->leaf);
+				fn->leaf = NULL;
+			}
+
+			fn->fn_sernum = sernum;
+
+			return fn;
+		}
+
+		/*
+		 *	We have more bits to go
+		 */
+
+		/* Try to walk down on tree. */
+		fn->fn_sernum = sernum;
+		dir = addr_bit_set(addr, fn->fn_bit);
+		pn = fn;
+		fn = dir ? fn->right : fn->left;
+	} 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();
+
+	if (!ln)
+		return ERR_PTR(-ENOMEM);
+	ln->fn_bit = plen;
+
+	ln->parent = pn;
+	ln->fn_sernum = sernum;
+
+	if (dir)
+		pn->right = ln;
+	else
+		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 = fn->parent;
+
+	/* 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();
+		ln = node_alloc();
+
+		if (!in || !ln) {
+			if (in)
+				node_free_immediate(in);
+			if (ln)
+				node_free_immediate(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;
+
+		in->parent = pn;
+		in->leaf = fn->leaf;
+		atomic_inc(&in->leaf->rt6i_ref);
+
+		in->fn_sernum = sernum;
+
+		/* update parent pointer */
+		if (dir)
+			pn->right = in;
+		else
+			pn->left  = in;
+
+		ln->fn_bit = plen;
+
+		ln->parent = in;
+		fn->parent = in;
+
+		ln->fn_sernum = sernum;
+
+		if (addr_bit_set(addr, bit)) {
+			in->right = ln;
+			in->left  = fn;
+		} else {
+			in->left  = ln;
+			in->right = fn;
+		}
+	} else { /* plen <= bit */
+
+		/*
+		 *		(new leaf node)[ln]
+		 *	          /	   \
+		 *	     (old node)[fn] NULL
+		 */
+
+		ln = node_alloc();
+
+		if (!ln)
+			return ERR_PTR(-ENOMEM);
+
+		ln->fn_bit = plen;
+
+		ln->parent = pn;
+
+		ln->fn_sernum = sernum;
+
+		if (dir)
+			pn->right = ln;
+		else
+			pn->left  = ln;
+
+		if (addr_bit_set(&key->addr, plen))
+			ln->right = fn;
+		else
+			ln->left  = fn;
+
+		fn->parent = ln;
+	}
+	return ln;
+}
+
+static bool rt6_qualify_for_ecmp(struct rt6_info *rt)
+{
+	return (rt->rt6i_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==
+	       RTF_GATEWAY;
+}
+
+static void fib6_copy_metrics(u32 *mp, const struct mx6_config *mxc)
+{
+	int i;
+
+	for (i = 0; i < RTAX_MAX; i++) {
+		if (test_bit(i, mxc->mx_valid))
+			mp[i] = mxc->mx[i];
+	}
+}
+
+static int fib6_commit_metrics(struct dst_entry *dst, struct mx6_config *mxc)
+{
+	if (!mxc->mx)
+		return 0;
+
+	if (dst->flags & DST_HOST) {
+		u32 *mp = dst_metrics_write_ptr(dst);
+
+		if (unlikely(!mp))
+			return -ENOMEM;
+
+		fib6_copy_metrics(mp, mxc);
+	} else {
+		dst_init_metrics(dst, mxc->mx, false);
+
+		/* We've stolen mx now. */
+		mxc->mx = NULL;
+	}
+
+	return 0;
+}
+
+static void fib6_purge_rt(struct rt6_info *rt, struct fib6_node *fn,
+			  struct net *net)
+{
+	if (atomic_read(&rt->rt6i_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) {
+			if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
+				fn->leaf = fib6_find_prefix(net, fn);
+				atomic_inc(&fn->leaf->rt6i_ref);
+				rt6_release(rt);
+			}
+			fn = fn->parent;
+		}
+	}
+}
+
+/*
+ *	Insert routing information in a node.
+ */
+
+static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
+			    struct nl_info *info, struct mx6_config *mxc)
+{
+	struct rt6_info *iter = NULL;
+	struct rt6_info **ins;
+	struct rt6_info **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 = fn->leaf; iter; iter = iter->dst.rt6_next) {
+		/*
+		 *	Search for duplicates
+		 */
+
+		if (iter->rt6i_metric == rt->rt6i_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->rt6i_nsiblings)
+					rt->rt6i_nsiblings = 0;
+				if (!(iter->rt6i_flags & RTF_EXPIRES))
+					return -EEXIST;
+				if (!(rt->rt6i_flags & RTF_EXPIRES))
+					rt6_clean_expires(iter);
+				else
+					rt6_set_expires(iter, rt->dst.expires);
+				iter->rt6i_pmtu = rt->rt6i_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->rt6i_nsiblings++;
+		}
+
+		if (iter->rt6i_metric > rt->rt6i_metric)
+			break;
+
+next_iter:
+		ins = &iter->dst.rt6_next;
+	}
+
+	if (fallback_ins && !found) {
+		/* No matching route with same ecmp-able-ness found, replace
+		 * first matching route
+		 */
+		ins = fallback_ins;
+		iter = *ins;
+		found++;
+	}
+
+	/* Reset round-robin state, if necessary */
+	if (ins == &fn->leaf)
+		fn->rr_ptr = NULL;
+
+	/* Link this route to others same route. */
+	if (rt->rt6i_nsiblings) {
+		unsigned int rt6i_nsiblings;
+		struct rt6_info *sibling, *temp_sibling;
+
+		/* Find the first route that have the same metric */
+		sibling = fn->leaf;
+		while (sibling) {
+			if (sibling->rt6i_metric == rt->rt6i_metric &&
+			    rt6_qualify_for_ecmp(sibling)) {
+				list_add_tail(&rt->rt6i_siblings,
+					      &sibling->rt6i_siblings);
+				break;
+			}
+			sibling = sibling->dst.rt6_next;
+		}
+		/* For each sibling in the list, increment the counter of
+		 * siblings. BUG() if counters does not match, list of siblings
+		 * is broken!
+		 */
+		rt6i_nsiblings = 0;
+		list_for_each_entry_safe(sibling, temp_sibling,
+					 &rt->rt6i_siblings, rt6i_siblings) {
+			sibling->rt6i_nsiblings++;
+			BUG_ON(sibling->rt6i_nsiblings != rt->rt6i_nsiblings);
+			rt6i_nsiblings++;
+		}
+		BUG_ON(rt6i_nsiblings != rt->rt6i_nsiblings);
+	}
+
+	/*
+	 *	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 = fib6_commit_metrics(&rt->dst, mxc);
+		if (err)
+			return err;
+
+		rt->dst.rt6_next = iter;
+		*ins = rt;
+		rcu_assign_pointer(rt->rt6i_node, fn);
+		atomic_inc(&rt->rt6i_ref);
+		call_fib6_entry_notifiers(info->nl_net, FIB_EVENT_ENTRY_ADD,
+					  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 = fib6_commit_metrics(&rt->dst, mxc);
+		if (err)
+			return err;
+
+		*ins = rt;
+		rcu_assign_pointer(rt->rt6i_node, fn);
+		rt->dst.rt6_next = iter->dst.rt6_next;
+		atomic_inc(&rt->rt6i_ref);
+		call_fib6_entry_notifiers(info->nl_net, FIB_EVENT_ENTRY_REPLACE,
+					  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->rt6i_nsiblings;
+		iter->rt6i_node = NULL;
+		fib6_purge_rt(iter, fn, info->nl_net);
+		if (fn->rr_ptr == iter)
+			fn->rr_ptr = NULL;
+		rt6_release(iter);
+
+		if (nsiblings) {
+			/* Replacing an ECMP route, remove all siblings */
+			ins = &rt->dst.rt6_next;
+			iter = *ins;
+			while (iter) {
+				if (iter->rt6i_metric > rt->rt6i_metric)
+					break;
+				if (rt6_qualify_for_ecmp(iter)) {
+					*ins = iter->dst.rt6_next;
+					iter->rt6i_node = NULL;
+					fib6_purge_rt(iter, fn, info->nl_net);
+					if (fn->rr_ptr == iter)
+						fn->rr_ptr = NULL;
+					rt6_release(iter);
+					nsiblings--;
+				} else {
+					ins = &iter->dst.rt6_next;
+				}
+				iter = *ins;
+			}
+			WARN_ON(nsiblings != 0);
+		}
+	}
+
+	return 0;
+}
+
+static void fib6_start_gc(struct net *net, struct rt6_info *rt)
+{
+	if (!timer_pending(&net->ipv6.ip6_fib_timer) &&
+	    (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE)))
+		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);
+}
+
+/*
+ *	Add routing information to the routing tree.
+ *	<destination addr>/<source addr>
+ *	with source addr info in sub-trees
+ */
+
+int fib6_add(struct fib6_node *root, struct rt6_info *rt,
+	     struct nl_info *info, struct mx6_config *mxc,
+	     struct netlink_ext_ack *extack)
+{
+	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 (WARN_ON_ONCE(!atomic_read(&rt->dst.__refcnt)))
+		return -EINVAL;
+
+	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(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
+			offsetof(struct rt6_info, rt6i_dst), allow_create,
+			replace_required, sernum, extack);
+	if (IS_ERR(fn)) {
+		err = PTR_ERR(fn);
+		fn = NULL;
+		goto out;
+	}
+
+	pn = fn;
+
+#ifdef CONFIG_IPV6_SUBTREES
+	if (rt->rt6i_src.plen) {
+		struct fib6_node *sn;
+
+		if (!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();
+			if (!sfn)
+				goto failure;
+
+			sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
+			atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
+			sfn->fn_flags = RTN_ROOT;
+			sfn->fn_sernum = sernum;
+
+			/* Now add the first leaf node to new subtree */
+
+			sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
+					rt->rt6i_src.plen,
+					offsetof(struct rt6_info, rt6i_src),
+					allow_create, replace_required, sernum,
+					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(sfn);
+				err = PTR_ERR(sn);
+				goto failure;
+			}
+
+			/* Now link new subtree to main tree */
+			sfn->parent = fn;
+			fn->subtree = sfn;
+		} else {
+			sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
+					rt->rt6i_src.plen,
+					offsetof(struct rt6_info, rt6i_src),
+					allow_create, replace_required, sernum,
+					extack);
+
+			if (IS_ERR(sn)) {
+				err = PTR_ERR(sn);
+				goto failure;
+			}
+		}
+
+		if (!fn->leaf) {
+			fn->leaf = rt;
+			atomic_inc(&rt->rt6i_ref);
+		}
+		fn = sn;
+	}
+#endif
+
+	err = fib6_add_rt2node(fn, rt, info, mxc);
+	if (!err) {
+		fib6_start_gc(info->nl_net, rt);
+		if (!(rt->rt6i_flags & RTF_CACHE))
+			fib6_prune_clones(info->nl_net, pn);
+	}
+
+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 && pn->leaf == rt) {
+			pn->leaf = NULL;
+			atomic_dec(&rt->rt6i_ref);
+		}
+		if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
+			pn->leaf = fib6_find_prefix(info->nl_net, pn);
+#if RT6_DEBUG >= 2
+			if (!pn->leaf) {
+				WARN_ON(pn->leaf == NULL);
+				pn->leaf = info->nl_net->ipv6.ip6_null_entry;
+			}
+#endif
+			atomic_inc(&pn->leaf->rt6i_ref);
+		}
+#endif
+		goto failure;
+	}
+	return err;
+
+failure:
+	/* fn->leaf could be NULL if 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.
+	 * In both cases, fib6_repair_tree() should be called to fix
+	 * fn->leaf.
+	 */
+	if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
+		fib6_repair_tree(info->nl_net, fn);
+	/* Always release dst as dst->__refcnt is guaranteed
+	 * to be taken before entering this function
+	 */
+	dst_release_immediate(&rt->dst);
+	return err;
+}
+
+/*
+ *	Routing tree lookup
+ *
+ */
+
+struct lookup_args {
+	int			offset;		/* key offset on rt6_info	*/
+	const struct in6_addr	*addr;		/* search key			*/
+};
+
+static struct fib6_node *fib6_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 ? fn->right : fn->left;
+
+		if (next) {
+			fn = next;
+			continue;
+		}
+		break;
+	}
+
+	while (fn) {
+		if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
+			struct rt6key *key;
+
+			key = (struct rt6key *) ((u8 *) fn->leaf +
+						 args->offset);
+
+			if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
+#ifdef CONFIG_IPV6_SUBTREES
+				if (fn->subtree) {
+					struct fib6_node *sfn;
+					sfn = fib6_lookup_1(fn->subtree,
+							    args + 1);
+					if (!sfn)
+						goto backtrack;
+					fn = sfn;
+				}
+#endif
+				if (fn->fn_flags & RTN_RTINFO)
+					return fn;
+			}
+		}
+#ifdef CONFIG_IPV6_SUBTREES
+backtrack:
+#endif
+		if (fn->fn_flags & RTN_ROOT)
+			break;
+
+		fn = fn->parent;
+	}
+
+	return NULL;
+}
+
+struct fib6_node *fib6_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 rt6_info, rt6i_dst),
+			.addr = daddr,
+		},
+#ifdef CONFIG_IPV6_SUBTREES
+		{
+			.offset = offsetof(struct rt6_info, rt6i_src),
+			.addr = saddr,
+		},
+#endif
+		{
+			.offset = 0,	/* sentinel */
+		}
+	};
+
+	fn = fib6_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)
+ */
+
+
+static struct fib6_node *fib6_locate_1(struct fib6_node *root,
+				       const struct in6_addr *addr,
+				       int plen, int offset)
+{
+	struct fib6_node *fn;
+
+	for (fn = root; fn ; ) {
+		struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
+
+		/*
+		 *	Prefix match
+		 */
+		if (plen < fn->fn_bit ||
+		    !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
+			return NULL;
+
+		if (plen == fn->fn_bit)
+			return fn;
+
+		/*
+		 *	We have more bits to go
+		 */
+		if (addr_bit_set(addr, fn->fn_bit))
+			fn = fn->right;
+		else
+			fn = fn->left;
+	}
+	return NULL;
+}
+
+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)
+{
+	struct fib6_node *fn;
+
+	fn = fib6_locate_1(root, daddr, dst_len,
+			   offsetof(struct rt6_info, rt6i_dst));
+
+#ifdef CONFIG_IPV6_SUBTREES
+	if (src_len) {
+		WARN_ON(saddr == NULL);
+		if (fn && fn->subtree)
+			fn = fib6_locate_1(fn->subtree, saddr, src_len,
+					   offsetof(struct rt6_info, rt6i_src));
+	}
+#endif
+
+	if (fn && fn->fn_flags & RTN_RTINFO)
+		return fn;
+
+	return NULL;
+}
+
+
+/*
+ *	Deletion
+ *
+ */
+
+static struct rt6_info *fib6_find_prefix(struct net *net, struct fib6_node *fn)
+{
+	if (fn->fn_flags & RTN_ROOT)
+		return net->ipv6.ip6_null_entry;
+
+	while (fn) {
+		if (fn->left)
+			return fn->left->leaf;
+		if (fn->right)
+			return fn->right->leaf;
+
+		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.
+ */
+
+static struct fib6_node *fib6_repair_tree(struct net *net,
+					   struct fib6_node *fn)
+{
+	int children;
+	int nstate;
+	struct fib6_node *child, *pn;
+	struct fib6_walker *w;
+	int iter = 0;
+
+	for (;;) {
+		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->right)
+			child = fn->right, children |= 1;
+		if (fn->left)
+			child = fn->left, 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
+		    ) {
+			fn->leaf = fib6_find_prefix(net, fn);
+#if RT6_DEBUG >= 2
+			if (!fn->leaf) {
+				WARN_ON(!fn->leaf);
+				fn->leaf = net->ipv6.ip6_null_entry;
+			}
+#endif
+			atomic_inc(&fn->leaf->rt6i_ref);
+			return fn->parent;
+		}
+
+		pn = fn->parent;
+#ifdef CONFIG_IPV6_SUBTREES
+		if (FIB6_SUBTREE(pn) == fn) {
+			WARN_ON(!(fn->fn_flags & RTN_ROOT));
+			FIB6_SUBTREE(pn) = NULL;
+			nstate = FWS_L;
+		} else {
+			WARN_ON(fn->fn_flags & RTN_ROOT);
+#endif
+			if (pn->right == fn)
+				pn->right = child;
+			else if (pn->left == fn)
+				pn->left = child;
+#if RT6_DEBUG >= 2
+			else
+				WARN_ON(1);
+#endif
+			if (child)
+				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->root == fn) {
+					w->root = w->node = NULL;
+					RT6_TRACE("W %p adjusted by delroot 1\n", w);
+				} else 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->root == fn) {
+					w->root = child;
+					RT6_TRACE("W %p adjusted by delroot 2\n", w);
+				}
+				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(fn);
+		if (pn->fn_flags & RTN_RTINFO || FIB6_SUBTREE(pn))
+			return pn;
+
+		rt6_release(pn->leaf);
+		pn->leaf = NULL;
+		fn = pn;
+	}
+}
+
+static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
+			   struct nl_info *info)
+{
+	struct fib6_walker *w;
+	struct rt6_info *rt = *rtp;
+	struct net *net = info->nl_net;
+
+	RT6_TRACE("fib6_del_route\n");
+
+	/* Unlink it */
+	*rtp = rt->dst.rt6_next;
+	rt->rt6i_node = NULL;
+	net->ipv6.rt6_stats->fib_rt_entries--;
+	net->ipv6.rt6_stats->fib_discarded_routes++;
+
+	/* Reset round-robin state, if necessary */
+	if (fn->rr_ptr == rt)
+		fn->rr_ptr = NULL;
+
+	/* Remove this entry from other siblings */
+	if (rt->rt6i_nsiblings) {
+		struct rt6_info *sibling, *next_sibling;
+
+		list_for_each_entry_safe(sibling, next_sibling,
+					 &rt->rt6i_siblings, rt6i_siblings)
+			sibling->rt6i_nsiblings--;
+		rt->rt6i_nsiblings = 0;
+		list_del_init(&rt->rt6i_siblings);
+	}
+
+	/* 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 = rt->dst.rt6_next;
+			if (!w->leaf)
+				w->state = FWS_U;
+		}
+	}
+	read_unlock(&net->ipv6.fib6_walker_lock);
+
+	rt->dst.rt6_next = NULL;
+
+	/* If it was last route, expunge its radix tree node */
+	if (!fn->leaf) {
+		fn->fn_flags &= ~RTN_RTINFO;
+		net->ipv6.rt6_stats->fib_route_nodes--;
+		fn = fib6_repair_tree(net, fn);
+	}
+
+	fib6_purge_rt(rt, fn, net);
+
+	call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, rt);
+	if (!info->skip_notify)
+		inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
+	rt6_release(rt);
+}
+
+int fib6_del(struct rt6_info *rt, struct nl_info *info)
+{
+	struct fib6_node *fn = rcu_dereference_protected(rt->rt6i_node,
+				    lockdep_is_held(&rt->rt6i_table->tb6_lock));
+	struct net *net = info->nl_net;
+	struct rt6_info **rtp;
+
+#if RT6_DEBUG >= 2
+	if (rt->dst.obsolete > 0) {
+		WARN_ON(fn);
+		return -ENOENT;
+	}
+#endif
+	if (!fn || rt == net->ipv6.ip6_null_entry)
+		return -ENOENT;
+
+	WARN_ON(!(fn->fn_flags & RTN_RTINFO));
+
+	if (!(rt->rt6i_flags & RTF_CACHE)) {
+		struct fib6_node *pn = fn;
+#ifdef CONFIG_IPV6_SUBTREES
+		/* clones of this route might be in another subtree */
+		if (rt->rt6i_src.plen) {
+			while (!(pn->fn_flags & RTN_ROOT))
+				pn = pn->parent;
+			pn = pn->parent;
+		}
+#endif
+		fib6_prune_clones(info->nl_net, pn);
+	}
+
+	/*
+	 *	Walk the leaf entries looking for ourself
+	 */
+
+	for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->dst.rt6_next) {
+		if (*rtp == rt) {
+			fib6_del_route(fn, rtp, info);
+			return 0;
+		}
+	}
+	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.
+ */
+
+static int fib6_walk_continue(struct fib6_walker *w)
+{
+	struct fib6_node *fn, *pn;
+
+	for (;;) {
+		fn = w->node;
+		if (!fn)
+			return 0;
+
+		if (w->prune && fn != w->root &&
+		    fn->fn_flags & RTN_RTINFO && w->state < FWS_C) {
+			w->state = FWS_C;
+			w->leaf = fn->leaf;
+		}
+		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
+		case FWS_L:
+			if (fn->left) {
+				w->node = fn->left;
+				w->state = FWS_INIT;
+				continue;
+			}
+			w->state = FWS_R;
+		case FWS_R:
+			if (fn->right) {
+				w->node = fn->right;
+				w->state = FWS_INIT;
+				continue;
+			}
+			w->state = FWS_C;
+			w->leaf = fn->leaf;
+		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;
+		case FWS_U:
+			if (fn == w->root)
+				return 0;
+			pn = fn->parent;
+			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 (pn->left == fn) {
+				w->state = FWS_R;
+				continue;
+			}
+			if (pn->right == fn) {
+				w->state = FWS_C;
+				w->leaf = w->node->leaf;
+				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 rt6_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 &&
+	    w->node->fn_sernum != c->sernum)
+		w->node->fn_sernum = c->sernum;
+
+	if (!c->func) {
+		WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
+		w->leaf = NULL;
+		return 0;
+	}
+
+	for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
+		res = c->func(rt, c->arg);
+		if (res < 0) {
+			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->rt6i_node),
+					 res);
+#endif
+				continue;
+			}
+			return 0;
+		}
+		WARN_ON(res != 0);
+	}
+	w->leaf = rt;
+	return 0;
+}
+
+/*
+ *	Convenient frontend to tree walker.
+ *
+ *	func is called on each route.
+ *		It may return -1 -> delete this route.
+ *		              0  -> continue walking
+ *
+ *	prune==1 -> only immediate children of node (certainly,
+ *	ignoring pure split nodes) will be scanned.
+ */
+
+static void fib6_clean_tree(struct net *net, struct fib6_node *root,
+			    int (*func)(struct rt6_info *, void *arg),
+			    bool prune, int sernum, void *arg)
+{
+	struct fib6_cleaner c;
+
+	c.w.root = root;
+	c.w.func = fib6_clean_node;
+	c.w.prune = prune;
+	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 rt6_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) {
+			write_lock_bh(&table->tb6_lock);
+			fib6_clean_tree(net, &table->tb6_root,
+					func, false, sernum, arg);
+			write_unlock_bh(&table->tb6_lock);
+		}
+	}
+	rcu_read_unlock();
+}
+
+void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *),
+		    void *arg)
+{
+	__fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
+}
+
+static int fib6_prune_clone(struct rt6_info *rt, void *arg)
+{
+	if (rt->rt6i_flags & RTF_CACHE) {
+		RT6_TRACE("pruning clone %p\n", rt);
+		return -1;
+	}
+
+	return 0;
+}
+
+static void fib6_prune_clones(struct net *net, struct fib6_node *fn)
+{
+	fib6_clean_tree(net, fn, fib6_prune_clone, true,
+			FIB6_NO_SERNUM_CHANGE, NULL);
+}
+
+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
+ */
+
+struct fib6_gc_args
+{
+	int			timeout;
+	int			more;
+};
+
+static int fib6_age(struct rt6_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.
+	 *
+	 *	Also age clones. Note, that clones are aged out
+	 *	only if they are not in use now.
+	 */
+
+	if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
+		if (time_after(now, rt->dst.expires)) {
+			RT6_TRACE("expiring %p\n", rt);
+			return -1;
+		}
+		gc_args->more++;
+	} else if (rt->rt6i_flags & RTF_CACHE) {
+		if (time_after_eq(now, rt->dst.lastuse + gc_args->timeout))
+			rt->dst.obsolete = DST_OBSOLETE_KILL;
+		if (atomic_read(&rt->dst.__refcnt) == 1 &&
+		    rt->dst.obsolete == DST_OBSOLETE_KILL) {
+			RT6_TRACE("aging clone %p\n", rt);
+			return -1;
+		} else if (rt->rt6i_flags & RTF_GATEWAY) {
+			struct neighbour *neigh;
+			__u8 neigh_flags = 0;
+
+			neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
+			if (neigh) {
+				neigh_flags = neigh->flags;
+				neigh_release(neigh);
+			}
+			if (!(neigh_flags & NTF_ROUTER)) {
+				RT6_TRACE("purging route %p via non-router but gateway\n",
+					  rt);
+				return -1;
+			}
+		}
+		gc_args->more++;
+	}
+
+	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(unsigned long arg)
+{
+	fib6_run_gc(0, (struct net *)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);
+	setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);
+
+	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;
+	net->ipv6.fib6_main_tbl->tb6_root.leaf = net->ipv6.ip6_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;
+	net->ipv6.fib6_local_tbl->tb6_root.leaf = net->ipv6.ip6_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;
+
+	rt6_ifdown(net, NULL);
+	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(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
+
+struct ipv6_route_iter {
+	struct seq_net_private p;
+	struct fib6_walker w;
+	loff_t skip;
+	struct fib6_table *tbl;
+	int sernum;
+};
+
+static int ipv6_route_seq_show(struct seq_file *seq, void *v)
+{
+	struct rt6_info *rt = v;
+	struct ipv6_route_iter *iter = seq->private;
+
+	seq_printf(seq, "%pi6 %02x ", &rt->rt6i_dst.addr, rt->rt6i_dst.plen);
+
+#ifdef CONFIG_IPV6_SUBTREES
+	seq_printf(seq, "%pi6 %02x ", &rt->rt6i_src.addr, rt->rt6i_src.plen);
+#else
+	seq_puts(seq, "00000000000000000000000000000000 00 ");
+#endif
+	if (rt->rt6i_flags & RTF_GATEWAY)
+		seq_printf(seq, "%pi6", &rt->rt6i_gateway);
+	else
+		seq_puts(seq, "00000000000000000000000000000000");
+
+	seq_printf(seq, " %08x %08x %08x %08x %8s\n",
+		   rt->rt6i_metric, atomic_read(&rt->dst.__refcnt),
+		   rt->dst.__use, rt->rt6i_flags,
+		   rt->dst.dev ? rt->dst.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 = iter->w.leaf->dst.rt6_next;
+		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 = 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)
+{
+	if (iter->sernum != iter->w.root->fn_sernum) {
+		iter->sernum = iter->w.root->fn_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 rt6_info *n;
+	struct net *net = seq_file_net(seq);
+	struct ipv6_route_iter *iter = seq->private;
+
+	if (!v)
+		goto iter_table;
+
+	n = ((struct rt6_info *)v)->dst.rt6_next;
+	if (n) {
+		++*pos;
+		return n;
+	}
+
+iter_table:
+	ipv6_route_check_sernum(iter);
+	read_lock(&iter->tbl->tb6_lock);
+	r = fib6_walk_continue(&iter->w);
+	read_unlock(&iter->tbl->tb6_lock);
+	if (r > 0) {
+		if (v)
+			++*pos;
+		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) {
+		ipv6_route_seq_setup_walk(iter, net);
+		return ipv6_route_seq_next(seq, NULL, pos);
+	} 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();
+}
+
+static 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
+};
+
+int ipv6_route_open(struct inode *inode, struct file *file)
+{
+	return seq_open_net(inode, file, &ipv6_route_seq_ops,
+			    sizeof(struct ipv6_route_iter));
+}
+
+#endif /* CONFIG_PROC_FS */