Adding upstream version 4.19.249.upstream/4.19.249upstream

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

1 files changed, 2751 insertions, 0 deletions

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
new file mode 100644
index 000000000..48d712550
--- /dev/null
+++ b/net/ipv4/fib_trie.c
@@ -0,0 +1,2751 @@
+/*
+ *   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.
+ *
+ *   Robert Olsson <robert.olsson@its.uu.se> Uppsala Universitet
+ *     & Swedish University of Agricultural Sciences.
+ *
+ *   Jens Laas <jens.laas@data.slu.se> Swedish University of
+ *     Agricultural Sciences.
+ *
+ *   Hans Liss <hans.liss@its.uu.se>  Uppsala Universitet
+ *
+ * This work is based on the LPC-trie which is originally described in:
+ *
+ * An experimental study of compression methods for dynamic tries
+ * Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
+ * http://www.csc.kth.se/~snilsson/software/dyntrie2/
+ *
+ *
+ * IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
+ * IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
+ *
+ *
+ * Code from fib_hash has been reused which includes the following header:
+ *
+ *
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		IPv4 FIB: lookup engine and maintenance routines.
+ *
+ *
+ * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ *
+ *		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.
+ *
+ * Substantial contributions to this work comes from:
+ *
+ *		David S. Miller, <davem@davemloft.net>
+ *		Stephen Hemminger <shemminger@osdl.org>
+ *		Paul E. McKenney <paulmck@us.ibm.com>
+ *		Patrick McHardy <kaber@trash.net>
+ */
+
+#define VERSION "0.409"
+
+#include <linux/cache.h>
+#include <linux/uaccess.h>
+#include <linux/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/errno.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/inetdevice.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/proc_fs.h>
+#include <linux/rcupdate.h>
+#include <linux/skbuff.h>
+#include <linux/netlink.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/vmalloc.h>
+#include <linux/notifier.h>
+#include <net/net_namespace.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <net/route.h>
+#include <net/tcp.h>
+#include <net/sock.h>
+#include <net/ip_fib.h>
+#include <net/fib_notifier.h>
+#include <trace/events/fib.h>
+#include "fib_lookup.h"
+
+static int call_fib_entry_notifier(struct notifier_block *nb, struct net *net,
+				   enum fib_event_type event_type, u32 dst,
+				   int dst_len, struct fib_alias *fa)
+{
+	struct fib_entry_notifier_info info = {
+		.dst = dst,
+		.dst_len = dst_len,
+		.fi = fa->fa_info,
+		.tos = fa->fa_tos,
+		.type = fa->fa_type,
+		.tb_id = fa->tb_id,
+	};
+	return call_fib4_notifier(nb, net, event_type, &info.info);
+}
+
+static int call_fib_entry_notifiers(struct net *net,
+				    enum fib_event_type event_type, u32 dst,
+				    int dst_len, struct fib_alias *fa,
+				    struct netlink_ext_ack *extack)
+{
+	struct fib_entry_notifier_info info = {
+		.info.extack = extack,
+		.dst = dst,
+		.dst_len = dst_len,
+		.fi = fa->fa_info,
+		.tos = fa->fa_tos,
+		.type = fa->fa_type,
+		.tb_id = fa->tb_id,
+	};
+	return call_fib4_notifiers(net, event_type, &info.info);
+}
+
+#define MAX_STAT_DEPTH 32
+
+#define KEYLENGTH	(8*sizeof(t_key))
+#define KEY_MAX		((t_key)~0)
+
+typedef unsigned int t_key;
+
+#define IS_TRIE(n)	((n)->pos >= KEYLENGTH)
+#define IS_TNODE(n)	((n)->bits)
+#define IS_LEAF(n)	(!(n)->bits)
+
+struct key_vector {
+	t_key key;
+	unsigned char pos;		/* 2log(KEYLENGTH) bits needed */
+	unsigned char bits;		/* 2log(KEYLENGTH) bits needed */
+	unsigned char slen;
+	union {
+		/* This list pointer if valid if (pos | bits) == 0 (LEAF) */
+		struct hlist_head leaf;
+		/* This array is valid if (pos | bits) > 0 (TNODE) */
+		struct key_vector __rcu *tnode[0];
+	};
+};
+
+struct tnode {
+	struct rcu_head rcu;
+	t_key empty_children;		/* KEYLENGTH bits needed */
+	t_key full_children;		/* KEYLENGTH bits needed */
+	struct key_vector __rcu *parent;
+	struct key_vector kv[1];
+#define tn_bits kv[0].bits
+};
+
+#define TNODE_SIZE(n)	offsetof(struct tnode, kv[0].tnode[n])
+#define LEAF_SIZE	TNODE_SIZE(1)
+
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+struct trie_use_stats {
+	unsigned int gets;
+	unsigned int backtrack;
+	unsigned int semantic_match_passed;
+	unsigned int semantic_match_miss;
+	unsigned int null_node_hit;
+	unsigned int resize_node_skipped;
+};
+#endif
+
+struct trie_stat {
+	unsigned int totdepth;
+	unsigned int maxdepth;
+	unsigned int tnodes;
+	unsigned int leaves;
+	unsigned int nullpointers;
+	unsigned int prefixes;
+	unsigned int nodesizes[MAX_STAT_DEPTH];
+};
+
+struct trie {
+	struct key_vector kv[1];
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+	struct trie_use_stats __percpu *stats;
+#endif
+};
+
+static struct key_vector *resize(struct trie *t, struct key_vector *tn);
+static size_t tnode_free_size;
+
+/*
+ * synchronize_rcu after call_rcu for that many pages; it should be especially
+ * useful before resizing the root node with PREEMPT_NONE configs; the value was
+ * obtained experimentally, aiming to avoid visible slowdown.
+ */
+static const int sync_pages = 128;
+
+static struct kmem_cache *fn_alias_kmem __ro_after_init;
+static struct kmem_cache *trie_leaf_kmem __ro_after_init;
+
+static inline struct tnode *tn_info(struct key_vector *kv)
+{
+	return container_of(kv, struct tnode, kv[0]);
+}
+
+/* caller must hold RTNL */
+#define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
+#define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
+
+/* caller must hold RCU read lock or RTNL */
+#define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
+#define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
+
+/* wrapper for rcu_assign_pointer */
+static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
+{
+	if (n)
+		rcu_assign_pointer(tn_info(n)->parent, tp);
+}
+
+#define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(n)->parent, p)
+
+/* This provides us with the number of children in this node, in the case of a
+ * leaf this will return 0 meaning none of the children are accessible.
+ */
+static inline unsigned long child_length(const struct key_vector *tn)
+{
+	return (1ul << tn->bits) & ~(1ul);
+}
+
+#define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
+
+static inline unsigned long get_index(t_key key, struct key_vector *kv)
+{
+	unsigned long index = key ^ kv->key;
+
+	if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
+		return 0;
+
+	return index >> kv->pos;
+}
+
+/* To understand this stuff, an understanding of keys and all their bits is
+ * necessary. Every node in the trie has a key associated with it, but not
+ * all of the bits in that key are significant.
+ *
+ * Consider a node 'n' and its parent 'tp'.
+ *
+ * If n is a leaf, every bit in its key is significant. Its presence is
+ * necessitated by path compression, since during a tree traversal (when
+ * searching for a leaf - unless we are doing an insertion) we will completely
+ * ignore all skipped bits we encounter. Thus we need to verify, at the end of
+ * a potentially successful search, that we have indeed been walking the
+ * correct key path.
+ *
+ * Note that we can never "miss" the correct key in the tree if present by
+ * following the wrong path. Path compression ensures that segments of the key
+ * that are the same for all keys with a given prefix are skipped, but the
+ * skipped part *is* identical for each node in the subtrie below the skipped
+ * bit! trie_insert() in this implementation takes care of that.
+ *
+ * if n is an internal node - a 'tnode' here, the various parts of its key
+ * have many different meanings.
+ *
+ * Example:
+ * _________________________________________________________________
+ * | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
+ * -----------------------------------------------------------------
+ *  31  30  29  28  27  26  25  24  23  22  21  20  19  18  17  16
+ *
+ * _________________________________________________________________
+ * | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
+ * -----------------------------------------------------------------
+ *  15  14  13  12  11  10   9   8   7   6   5   4   3   2   1   0
+ *
+ * tp->pos = 22
+ * tp->bits = 3
+ * n->pos = 13
+ * n->bits = 4
+ *
+ * First, let's just ignore the bits that come before the parent tp, that is
+ * the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
+ * point we do not use them for anything.
+ *
+ * The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
+ * index into the parent's child array. That is, they will be used to find
+ * 'n' among tp's children.
+ *
+ * The bits from (n->pos + n->bits) to (tp->pos - 1) - "S" - are skipped bits
+ * for the node n.
+ *
+ * All the bits we have seen so far are significant to the node n. The rest
+ * of the bits are really not needed or indeed known in n->key.
+ *
+ * The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
+ * n's child array, and will of course be different for each child.
+ *
+ * The rest of the bits, from 0 to (n->pos -1) - "u" - are completely unknown
+ * at this point.
+ */
+
+static const int halve_threshold = 25;
+static const int inflate_threshold = 50;
+static const int halve_threshold_root = 15;
+static const int inflate_threshold_root = 30;
+
+static void __alias_free_mem(struct rcu_head *head)
+{
+	struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
+	kmem_cache_free(fn_alias_kmem, fa);
+}
+
+static inline void alias_free_mem_rcu(struct fib_alias *fa)
+{
+	call_rcu(&fa->rcu, __alias_free_mem);
+}
+
+#define TNODE_KMALLOC_MAX \
+	ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct key_vector *))
+#define TNODE_VMALLOC_MAX \
+	ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
+
+static void __node_free_rcu(struct rcu_head *head)
+{
+	struct tnode *n = container_of(head, struct tnode, rcu);
+
+	if (!n->tn_bits)
+		kmem_cache_free(trie_leaf_kmem, n);
+	else
+		kvfree(n);
+}
+
+#define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
+
+static struct tnode *tnode_alloc(int bits)
+{
+	size_t size;
+
+	/* verify bits is within bounds */
+	if (bits > TNODE_VMALLOC_MAX)
+		return NULL;
+
+	/* determine size and verify it is non-zero and didn't overflow */
+	size = TNODE_SIZE(1ul << bits);
+
+	if (size <= PAGE_SIZE)
+		return kzalloc(size, GFP_KERNEL);
+	else
+		return vzalloc(size);
+}
+
+static inline void empty_child_inc(struct key_vector *n)
+{
+	++tn_info(n)->empty_children ? : ++tn_info(n)->full_children;
+}
+
+static inline void empty_child_dec(struct key_vector *n)
+{
+	tn_info(n)->empty_children-- ? : tn_info(n)->full_children--;
+}
+
+static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
+{
+	struct key_vector *l;
+	struct tnode *kv;
+
+	kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
+	if (!kv)
+		return NULL;
+
+	/* initialize key vector */
+	l = kv->kv;
+	l->key = key;
+	l->pos = 0;
+	l->bits = 0;
+	l->slen = fa->fa_slen;
+
+	/* link leaf to fib alias */
+	INIT_HLIST_HEAD(&l->leaf);
+	hlist_add_head(&fa->fa_list, &l->leaf);
+
+	return l;
+}
+
+static struct key_vector *tnode_new(t_key key, int pos, int bits)
+{
+	unsigned int shift = pos + bits;
+	struct key_vector *tn;
+	struct tnode *tnode;
+
+	/* verify bits and pos their msb bits clear and values are valid */
+	BUG_ON(!bits || (shift > KEYLENGTH));
+
+	tnode = tnode_alloc(bits);
+	if (!tnode)
+		return NULL;
+
+	pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
+		 sizeof(struct key_vector *) << bits);
+
+	if (bits == KEYLENGTH)
+		tnode->full_children = 1;
+	else
+		tnode->empty_children = 1ul << bits;
+
+	tn = tnode->kv;
+	tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
+	tn->pos = pos;
+	tn->bits = bits;
+	tn->slen = pos;
+
+	return tn;
+}
+
+/* Check whether a tnode 'n' is "full", i.e. it is an internal node
+ * and no bits are skipped. See discussion in dyntree paper p. 6
+ */
+static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
+{
+	return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
+}
+
+/* Add a child at position i overwriting the old value.
+ * Update the value of full_children and empty_children.
+ */
+static void put_child(struct key_vector *tn, unsigned long i,
+		      struct key_vector *n)
+{
+	struct key_vector *chi = get_child(tn, i);
+	int isfull, wasfull;
+
+	BUG_ON(i >= child_length(tn));
+
+	/* update emptyChildren, overflow into fullChildren */
+	if (!n && chi)
+		empty_child_inc(tn);
+	if (n && !chi)
+		empty_child_dec(tn);
+
+	/* update fullChildren */
+	wasfull = tnode_full(tn, chi);
+	isfull = tnode_full(tn, n);
+
+	if (wasfull && !isfull)
+		tn_info(tn)->full_children--;
+	else if (!wasfull && isfull)
+		tn_info(tn)->full_children++;
+
+	if (n && (tn->slen < n->slen))
+		tn->slen = n->slen;
+
+	rcu_assign_pointer(tn->tnode[i], n);
+}
+
+static void update_children(struct key_vector *tn)
+{
+	unsigned long i;
+
+	/* update all of the child parent pointers */
+	for (i = child_length(tn); i;) {
+		struct key_vector *inode = get_child(tn, --i);
+
+		if (!inode)
+			continue;
+
+		/* Either update the children of a tnode that
+		 * already belongs to us or update the child
+		 * to point to ourselves.
+		 */
+		if (node_parent(inode) == tn)
+			update_children(inode);
+		else
+			node_set_parent(inode, tn);
+	}
+}
+
+static inline void put_child_root(struct key_vector *tp, t_key key,
+				  struct key_vector *n)
+{
+	if (IS_TRIE(tp))
+		rcu_assign_pointer(tp->tnode[0], n);
+	else
+		put_child(tp, get_index(key, tp), n);
+}
+
+static inline void tnode_free_init(struct key_vector *tn)
+{
+	tn_info(tn)->rcu.next = NULL;
+}
+
+static inline void tnode_free_append(struct key_vector *tn,
+				     struct key_vector *n)
+{
+	tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
+	tn_info(tn)->rcu.next = &tn_info(n)->rcu;
+}
+
+static void tnode_free(struct key_vector *tn)
+{
+	struct callback_head *head = &tn_info(tn)->rcu;
+
+	while (head) {
+		head = head->next;
+		tnode_free_size += TNODE_SIZE(1ul << tn->bits);
+		node_free(tn);
+
+		tn = container_of(head, struct tnode, rcu)->kv;
+	}
+
+	if (tnode_free_size >= PAGE_SIZE * sync_pages) {
+		tnode_free_size = 0;
+		synchronize_rcu();
+	}
+}
+
+static struct key_vector *replace(struct trie *t,
+				  struct key_vector *oldtnode,
+				  struct key_vector *tn)
+{
+	struct key_vector *tp = node_parent(oldtnode);
+	unsigned long i;
+
+	/* setup the parent pointer out of and back into this node */
+	NODE_INIT_PARENT(tn, tp);
+	put_child_root(tp, tn->key, tn);
+
+	/* update all of the child parent pointers */
+	update_children(tn);
+
+	/* all pointers should be clean so we are done */
+	tnode_free(oldtnode);
+
+	/* resize children now that oldtnode is freed */
+	for (i = child_length(tn); i;) {
+		struct key_vector *inode = get_child(tn, --i);
+
+		/* resize child node */
+		if (tnode_full(tn, inode))
+			tn = resize(t, inode);
+	}
+
+	return tp;
+}
+
+static struct key_vector *inflate(struct trie *t,
+				  struct key_vector *oldtnode)
+{
+	struct key_vector *tn;
+	unsigned long i;
+	t_key m;
+
+	pr_debug("In inflate\n");
+
+	tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
+	if (!tn)
+		goto notnode;
+
+	/* prepare oldtnode to be freed */
+	tnode_free_init(oldtnode);
+
+	/* Assemble all of the pointers in our cluster, in this case that
+	 * represents all of the pointers out of our allocated nodes that
+	 * point to existing tnodes and the links between our allocated
+	 * nodes.
+	 */
+	for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
+		struct key_vector *inode = get_child(oldtnode, --i);
+		struct key_vector *node0, *node1;
+		unsigned long j, k;
+
+		/* An empty child */
+		if (!inode)
+			continue;
+
+		/* A leaf or an internal node with skipped bits */
+		if (!tnode_full(oldtnode, inode)) {
+			put_child(tn, get_index(inode->key, tn), inode);
+			continue;
+		}
+
+		/* drop the node in the old tnode free list */
+		tnode_free_append(oldtnode, inode);
+
+		/* An internal node with two children */
+		if (inode->bits == 1) {
+			put_child(tn, 2 * i + 1, get_child(inode, 1));
+			put_child(tn, 2 * i, get_child(inode, 0));
+			continue;
+		}
+
+		/* We will replace this node 'inode' with two new
+		 * ones, 'node0' and 'node1', each with half of the
+		 * original children. The two new nodes will have
+		 * a position one bit further down the key and this
+		 * means that the "significant" part of their keys
+		 * (see the discussion near the top of this file)
+		 * will differ by one bit, which will be "0" in
+		 * node0's key and "1" in node1's key. Since we are
+		 * moving the key position by one step, the bit that
+		 * we are moving away from - the bit at position
+		 * (tn->pos) - is the one that will differ between
+		 * node0 and node1. So... we synthesize that bit in the
+		 * two new keys.
+		 */
+		node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
+		if (!node1)
+			goto nomem;
+		node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
+
+		tnode_free_append(tn, node1);
+		if (!node0)
+			goto nomem;
+		tnode_free_append(tn, node0);
+
+		/* populate child pointers in new nodes */
+		for (k = child_length(inode), j = k / 2; j;) {
+			put_child(node1, --j, get_child(inode, --k));
+			put_child(node0, j, get_child(inode, j));
+			put_child(node1, --j, get_child(inode, --k));
+			put_child(node0, j, get_child(inode, j));
+		}
+
+		/* link new nodes to parent */
+		NODE_INIT_PARENT(node1, tn);
+		NODE_INIT_PARENT(node0, tn);
+
+		/* link parent to nodes */
+		put_child(tn, 2 * i + 1, node1);
+		put_child(tn, 2 * i, node0);
+	}
+
+	/* setup the parent pointers into and out of this node */
+	return replace(t, oldtnode, tn);
+nomem:
+	/* all pointers should be clean so we are done */
+	tnode_free(tn);
+notnode:
+	return NULL;
+}
+
+static struct key_vector *halve(struct trie *t,
+				struct key_vector *oldtnode)
+{
+	struct key_vector *tn;
+	unsigned long i;
+
+	pr_debug("In halve\n");
+
+	tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
+	if (!tn)
+		goto notnode;
+
+	/* prepare oldtnode to be freed */
+	tnode_free_init(oldtnode);
+
+	/* Assemble all of the pointers in our cluster, in this case that
+	 * represents all of the pointers out of our allocated nodes that
+	 * point to existing tnodes and the links between our allocated
+	 * nodes.
+	 */
+	for (i = child_length(oldtnode); i;) {
+		struct key_vector *node1 = get_child(oldtnode, --i);
+		struct key_vector *node0 = get_child(oldtnode, --i);
+		struct key_vector *inode;
+
+		/* At least one of the children is empty */
+		if (!node1 || !node0) {
+			put_child(tn, i / 2, node1 ? : node0);
+			continue;
+		}
+
+		/* Two nonempty children */
+		inode = tnode_new(node0->key, oldtnode->pos, 1);
+		if (!inode)
+			goto nomem;
+		tnode_free_append(tn, inode);
+
+		/* initialize pointers out of node */
+		put_child(inode, 1, node1);
+		put_child(inode, 0, node0);
+		NODE_INIT_PARENT(inode, tn);
+
+		/* link parent to node */
+		put_child(tn, i / 2, inode);
+	}
+
+	/* setup the parent pointers into and out of this node */
+	return replace(t, oldtnode, tn);
+nomem:
+	/* all pointers should be clean so we are done */
+	tnode_free(tn);
+notnode:
+	return NULL;
+}
+
+static struct key_vector *collapse(struct trie *t,
+				   struct key_vector *oldtnode)
+{
+	struct key_vector *n, *tp;
+	unsigned long i;
+
+	/* scan the tnode looking for that one child that might still exist */
+	for (n = NULL, i = child_length(oldtnode); !n && i;)
+		n = get_child(oldtnode, --i);
+
+	/* compress one level */
+	tp = node_parent(oldtnode);
+	put_child_root(tp, oldtnode->key, n);
+	node_set_parent(n, tp);
+
+	/* drop dead node */
+	node_free(oldtnode);
+
+	return tp;
+}
+
+static unsigned char update_suffix(struct key_vector *tn)
+{
+	unsigned char slen = tn->pos;
+	unsigned long stride, i;
+	unsigned char slen_max;
+
+	/* only vector 0 can have a suffix length greater than or equal to
+	 * tn->pos + tn->bits, the second highest node will have a suffix
+	 * length at most of tn->pos + tn->bits - 1
+	 */
+	slen_max = min_t(unsigned char, tn->pos + tn->bits - 1, tn->slen);
+
+	/* search though the list of children looking for nodes that might
+	 * have a suffix greater than the one we currently have.  This is
+	 * why we start with a stride of 2 since a stride of 1 would
+	 * represent the nodes with suffix length equal to tn->pos
+	 */
+	for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
+		struct key_vector *n = get_child(tn, i);
+
+		if (!n || (n->slen <= slen))
+			continue;
+
+		/* update stride and slen based on new value */
+		stride <<= (n->slen - slen);
+		slen = n->slen;
+		i &= ~(stride - 1);
+
+		/* stop searching if we have hit the maximum possible value */
+		if (slen >= slen_max)
+			break;
+	}
+
+	tn->slen = slen;
+
+	return slen;
+}
+
+/* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
+ * the Helsinki University of Technology and Matti Tikkanen of Nokia
+ * Telecommunications, page 6:
+ * "A node is doubled if the ratio of non-empty children to all
+ * children in the *doubled* node is at least 'high'."
+ *
+ * 'high' in this instance is the variable 'inflate_threshold'. It
+ * is expressed as a percentage, so we multiply it with
+ * child_length() and instead of multiplying by 2 (since the
+ * child array will be doubled by inflate()) and multiplying
+ * the left-hand side by 100 (to handle the percentage thing) we
+ * multiply the left-hand side by 50.
+ *
+ * The left-hand side may look a bit weird: child_length(tn)
+ * - tn->empty_children is of course the number of non-null children
+ * in the current node. tn->full_children is the number of "full"
+ * children, that is non-null tnodes with a skip value of 0.
+ * All of those will be doubled in the resulting inflated tnode, so
+ * we just count them one extra time here.
+ *
+ * A clearer way to write this would be:
+ *
+ * to_be_doubled = tn->full_children;
+ * not_to_be_doubled = child_length(tn) - tn->empty_children -
+ *     tn->full_children;
+ *
+ * new_child_length = child_length(tn) * 2;
+ *
+ * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
+ *      new_child_length;
+ * if (new_fill_factor >= inflate_threshold)
+ *
+ * ...and so on, tho it would mess up the while () loop.
+ *
+ * anyway,
+ * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
+ *      inflate_threshold
+ *
+ * avoid a division:
+ * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
+ *      inflate_threshold * new_child_length
+ *
+ * expand not_to_be_doubled and to_be_doubled, and shorten:
+ * 100 * (child_length(tn) - tn->empty_children +
+ *    tn->full_children) >= inflate_threshold * new_child_length
+ *
+ * expand new_child_length:
+ * 100 * (child_length(tn) - tn->empty_children +
+ *    tn->full_children) >=
+ *      inflate_threshold * child_length(tn) * 2
+ *
+ * shorten again:
+ * 50 * (tn->full_children + child_length(tn) -
+ *    tn->empty_children) >= inflate_threshold *
+ *    child_length(tn)
+ *
+ */
+static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
+{
+	unsigned long used = child_length(tn);
+	unsigned long threshold = used;
+
+	/* Keep root node larger */
+	threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
+	used -= tn_info(tn)->empty_children;
+	used += tn_info(tn)->full_children;
+
+	/* if bits == KEYLENGTH then pos = 0, and will fail below */
+
+	return (used > 1) && tn->pos && ((50 * used) >= threshold);
+}
+
+static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
+{
+	unsigned long used = child_length(tn);
+	unsigned long threshold = used;
+
+	/* Keep root node larger */
+	threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
+	used -= tn_info(tn)->empty_children;
+
+	/* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
+
+	return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
+}
+
+static inline bool should_collapse(struct key_vector *tn)
+{
+	unsigned long used = child_length(tn);
+
+	used -= tn_info(tn)->empty_children;
+
+	/* account for bits == KEYLENGTH case */
+	if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
+		used -= KEY_MAX;
+
+	/* One child or none, time to drop us from the trie */
+	return used < 2;
+}
+
+#define MAX_WORK 10
+static struct key_vector *resize(struct trie *t, struct key_vector *tn)
+{
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+	struct trie_use_stats __percpu *stats = t->stats;
+#endif
+	struct key_vector *tp = node_parent(tn);
+	unsigned long cindex = get_index(tn->key, tp);
+	int max_work = MAX_WORK;
+
+	pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
+		 tn, inflate_threshold, halve_threshold);
+
+	/* track the tnode via the pointer from the parent instead of
+	 * doing it ourselves.  This way we can let RCU fully do its
+	 * thing without us interfering
+	 */
+	BUG_ON(tn != get_child(tp, cindex));
+
+	/* Double as long as the resulting node has a number of
+	 * nonempty nodes that are above the threshold.
+	 */
+	while (should_inflate(tp, tn) && max_work) {
+		tp = inflate(t, tn);
+		if (!tp) {
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+			this_cpu_inc(stats->resize_node_skipped);
+#endif
+			break;
+		}
+
+		max_work--;
+		tn = get_child(tp, cindex);
+	}
+
+	/* update parent in case inflate failed */
+	tp = node_parent(tn);
+
+	/* Return if at least one inflate is run */
+	if (max_work != MAX_WORK)
+		return tp;
+
+	/* Halve as long as the number of empty children in this
+	 * node is above threshold.
+	 */
+	while (should_halve(tp, tn) && max_work) {
+		tp = halve(t, tn);
+		if (!tp) {
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+			this_cpu_inc(stats->resize_node_skipped);
+#endif
+			break;
+		}
+
+		max_work--;
+		tn = get_child(tp, cindex);
+	}
+
+	/* Only one child remains */
+	if (should_collapse(tn))
+		return collapse(t, tn);
+
+	/* update parent in case halve failed */
+	return node_parent(tn);
+}
+
+static void node_pull_suffix(struct key_vector *tn, unsigned char slen)
+{
+	unsigned char node_slen = tn->slen;
+
+	while ((node_slen > tn->pos) && (node_slen > slen)) {
+		slen = update_suffix(tn);
+		if (node_slen == slen)
+			break;
+
+		tn = node_parent(tn);
+		node_slen = tn->slen;
+	}
+}
+
+static void node_push_suffix(struct key_vector *tn, unsigned char slen)
+{
+	while (tn->slen < slen) {
+		tn->slen = slen;
+		tn = node_parent(tn);
+	}
+}
+
+/* rcu_read_lock needs to be hold by caller from readside */
+static struct key_vector *fib_find_node(struct trie *t,
+					struct key_vector **tp, u32 key)
+{
+	struct key_vector *pn, *n = t->kv;
+	unsigned long index = 0;
+
+	do {
+		pn = n;
+		n = get_child_rcu(n, index);
+
+		if (!n)
+			break;
+
+		index = get_cindex(key, n);
+
+		/* This bit of code is a bit tricky but it combines multiple
+		 * checks into a single check.  The prefix consists of the
+		 * prefix plus zeros for the bits in the cindex. The index
+		 * is the difference between the key and this value.  From
+		 * this we can actually derive several pieces of data.
+		 *   if (index >= (1ul << bits))
+		 *     we have a mismatch in skip bits and failed
+		 *   else
+		 *     we know the value is cindex
+		 *
+		 * This check is safe even if bits == KEYLENGTH due to the
+		 * fact that we can only allocate a node with 32 bits if a
+		 * long is greater than 32 bits.
+		 */
+		if (index >= (1ul << n->bits)) {
+			n = NULL;
+			break;
+		}
+
+		/* keep searching until we find a perfect match leaf or NULL */
+	} while (IS_TNODE(n));
+
+	*tp = pn;
+
+	return n;
+}
+
+/* Return the first fib alias matching TOS with
+ * priority less than or equal to PRIO.
+ */
+static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
+					u8 tos, u32 prio, u32 tb_id)
+{
+	struct fib_alias *fa;
+
+	if (!fah)
+		return NULL;
+
+	hlist_for_each_entry(fa, fah, fa_list) {
+		if (fa->fa_slen < slen)
+			continue;
+		if (fa->fa_slen != slen)
+			break;
+		if (fa->tb_id > tb_id)
+			continue;
+		if (fa->tb_id != tb_id)
+			break;
+		if (fa->fa_tos > tos)
+			continue;
+		if (fa->fa_info->fib_priority >= prio || fa->fa_tos < tos)
+			return fa;
+	}
+
+	return NULL;
+}
+
+static void trie_rebalance(struct trie *t, struct key_vector *tn)
+{
+	while (!IS_TRIE(tn))
+		tn = resize(t, tn);
+}
+
+static int fib_insert_node(struct trie *t, struct key_vector *tp,
+			   struct fib_alias *new, t_key key)
+{
+	struct key_vector *n, *l;
+
+	l = leaf_new(key, new);
+	if (!l)
+		goto noleaf;
+
+	/* retrieve child from parent node */
+	n = get_child(tp, get_index(key, tp));
+
+	/* Case 2: n is a LEAF or a TNODE and the key doesn't match.
+	 *
+	 *  Add a new tnode here
+	 *  first tnode need some special handling
+	 *  leaves us in position for handling as case 3
+	 */
+	if (n) {
+		struct key_vector *tn;
+
+		tn = tnode_new(key, __fls(key ^ n->key), 1);
+		if (!tn)
+			goto notnode;
+
+		/* initialize routes out of node */
+		NODE_INIT_PARENT(tn, tp);
+		put_child(tn, get_index(key, tn) ^ 1, n);
+
+		/* start adding routes into the node */
+		put_child_root(tp, key, tn);
+		node_set_parent(n, tn);
+
+		/* parent now has a NULL spot where the leaf can go */
+		tp = tn;
+	}
+
+	/* Case 3: n is NULL, and will just insert a new leaf */
+	node_push_suffix(tp, new->fa_slen);
+	NODE_INIT_PARENT(l, tp);
+	put_child_root(tp, key, l);
+	trie_rebalance(t, tp);
+
+	return 0;
+notnode:
+	node_free(l);
+noleaf:
+	return -ENOMEM;
+}
+
+/* fib notifier for ADD is sent before calling fib_insert_alias with
+ * the expectation that the only possible failure ENOMEM
+ */
+static int fib_insert_alias(struct trie *t, struct key_vector *tp,
+			    struct key_vector *l, struct fib_alias *new,
+			    struct fib_alias *fa, t_key key)
+{
+	if (!l)
+		return fib_insert_node(t, tp, new, key);
+
+	if (fa) {
+		hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
+	} else {
+		struct fib_alias *last;
+
+		hlist_for_each_entry(last, &l->leaf, fa_list) {
+			if (new->fa_slen < last->fa_slen)
+				break;
+			if ((new->fa_slen == last->fa_slen) &&
+			    (new->tb_id > last->tb_id))
+				break;
+			fa = last;
+		}
+
+		if (fa)
+			hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
+		else
+			hlist_add_head_rcu(&new->fa_list, &l->leaf);
+	}
+
+	/* if we added to the tail node then we need to update slen */
+	if (l->slen < new->fa_slen) {
+		l->slen = new->fa_slen;
+		node_push_suffix(tp, new->fa_slen);
+	}
+
+	return 0;
+}
+
+static bool fib_valid_key_len(u32 key, u8 plen, struct netlink_ext_ack *extack)
+{
+	if (plen > KEYLENGTH) {
+		NL_SET_ERR_MSG(extack, "Invalid prefix length");
+		return false;
+	}
+
+	if ((plen < KEYLENGTH) && (key << plen)) {
+		NL_SET_ERR_MSG(extack,
+			       "Invalid prefix for given prefix length");
+		return false;
+	}
+
+	return true;
+}
+
+/* Caller must hold RTNL. */
+int fib_table_insert(struct net *net, struct fib_table *tb,
+		     struct fib_config *cfg, struct netlink_ext_ack *extack)
+{
+	enum fib_event_type event = FIB_EVENT_ENTRY_ADD;
+	struct trie *t = (struct trie *)tb->tb_data;
+	struct fib_alias *fa, *new_fa;
+	struct key_vector *l, *tp;
+	u16 nlflags = NLM_F_EXCL;
+	struct fib_info *fi;
+	u8 plen = cfg->fc_dst_len;
+	u8 slen = KEYLENGTH - plen;
+	u8 tos = cfg->fc_tos;
+	u32 key;
+	int err;
+
+	key = ntohl(cfg->fc_dst);
+
+	if (!fib_valid_key_len(key, plen, extack))
+		return -EINVAL;
+
+	pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
+
+	fi = fib_create_info(cfg, extack);
+	if (IS_ERR(fi)) {
+		err = PTR_ERR(fi);
+		goto err;
+	}
+
+	l = fib_find_node(t, &tp, key);
+	fa = l ? fib_find_alias(&l->leaf, slen, tos, fi->fib_priority,
+				tb->tb_id) : NULL;
+
+	/* Now fa, if non-NULL, points to the first fib alias
+	 * with the same keys [prefix,tos,priority], if such key already
+	 * exists or to the node before which we will insert new one.
+	 *
+	 * If fa is NULL, we will need to allocate a new one and
+	 * insert to the tail of the section matching the suffix length
+	 * of the new alias.
+	 */
+
+	if (fa && fa->fa_tos == tos &&
+	    fa->fa_info->fib_priority == fi->fib_priority) {
+		struct fib_alias *fa_first, *fa_match;
+
+		err = -EEXIST;
+		if (cfg->fc_nlflags & NLM_F_EXCL)
+			goto out;
+
+		nlflags &= ~NLM_F_EXCL;
+
+		/* We have 2 goals:
+		 * 1. Find exact match for type, scope, fib_info to avoid
+		 * duplicate routes
+		 * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
+		 */
+		fa_match = NULL;
+		fa_first = fa;
+		hlist_for_each_entry_from(fa, fa_list) {
+			if ((fa->fa_slen != slen) ||
+			    (fa->tb_id != tb->tb_id) ||
+			    (fa->fa_tos != tos))
+				break;
+			if (fa->fa_info->fib_priority != fi->fib_priority)
+				break;
+			if (fa->fa_type == cfg->fc_type &&
+			    fa->fa_info == fi) {
+				fa_match = fa;
+				break;
+			}
+		}
+
+		if (cfg->fc_nlflags & NLM_F_REPLACE) {
+			struct fib_info *fi_drop;
+			u8 state;
+
+			nlflags |= NLM_F_REPLACE;
+			fa = fa_first;
+			if (fa_match) {
+				if (fa == fa_match)
+					err = 0;
+				goto out;
+			}
+			err = -ENOBUFS;
+			new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
+			if (!new_fa)
+				goto out;
+
+			fi_drop = fa->fa_info;
+			new_fa->fa_tos = fa->fa_tos;
+			new_fa->fa_info = fi;
+			new_fa->fa_type = cfg->fc_type;
+			state = fa->fa_state;
+			new_fa->fa_state = state & ~FA_S_ACCESSED;
+			new_fa->fa_slen = fa->fa_slen;
+			new_fa->tb_id = tb->tb_id;
+			new_fa->fa_default = -1;
+
+			err = call_fib_entry_notifiers(net,
+						       FIB_EVENT_ENTRY_REPLACE,
+						       key, plen, new_fa,
+						       extack);
+			if (err)
+				goto out_free_new_fa;
+
+			rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
+				  tb->tb_id, &cfg->fc_nlinfo, nlflags);
+
+			hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
+
+			alias_free_mem_rcu(fa);
+
+			fib_release_info(fi_drop);
+			if (state & FA_S_ACCESSED)
+				rt_cache_flush(cfg->fc_nlinfo.nl_net);
+
+			goto succeeded;
+		}
+		/* Error if we find a perfect match which
+		 * uses the same scope, type, and nexthop
+		 * information.
+		 */
+		if (fa_match)
+			goto out;
+
+		if (cfg->fc_nlflags & NLM_F_APPEND) {
+			event = FIB_EVENT_ENTRY_APPEND;
+			nlflags |= NLM_F_APPEND;
+		} else {
+			fa = fa_first;
+		}
+	}
+	err = -ENOENT;
+	if (!(cfg->fc_nlflags & NLM_F_CREATE))
+		goto out;
+
+	nlflags |= NLM_F_CREATE;
+	err = -ENOBUFS;
+	new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
+	if (!new_fa)
+		goto out;
+
+	new_fa->fa_info = fi;
+	new_fa->fa_tos = tos;
+	new_fa->fa_type = cfg->fc_type;
+	new_fa->fa_state = 0;
+	new_fa->fa_slen = slen;
+	new_fa->tb_id = tb->tb_id;
+	new_fa->fa_default = -1;
+
+	err = call_fib_entry_notifiers(net, event, key, plen, new_fa, extack);
+	if (err)
+		goto out_free_new_fa;
+
+	/* Insert new entry to the list. */
+	err = fib_insert_alias(t, tp, l, new_fa, fa, key);
+	if (err)
+		goto out_fib_notif;
+
+	if (!plen)
+		tb->tb_num_default++;
+
+	rt_cache_flush(cfg->fc_nlinfo.nl_net);
+	rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
+		  &cfg->fc_nlinfo, nlflags);
+succeeded:
+	return 0;
+
+out_fib_notif:
+	/* notifier was sent that entry would be added to trie, but
+	 * the add failed and need to recover. Only failure for
+	 * fib_insert_alias is ENOMEM.
+	 */
+	NL_SET_ERR_MSG(extack, "Failed to insert route into trie");
+	call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key,
+				 plen, new_fa, NULL);
+out_free_new_fa:
+	kmem_cache_free(fn_alias_kmem, new_fa);
+out:
+	fib_release_info(fi);
+err:
+	return err;
+}
+
+static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
+{
+	t_key prefix = n->key;
+
+	return (key ^ prefix) & (prefix | -prefix);
+}
+
+/* should be called with rcu_read_lock */
+int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
+		     struct fib_result *res, int fib_flags)
+{
+	struct trie *t = (struct trie *) tb->tb_data;
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+	struct trie_use_stats __percpu *stats = t->stats;
+#endif
+	const t_key key = ntohl(flp->daddr);
+	struct key_vector *n, *pn;
+	struct fib_alias *fa;
+	unsigned long index;
+	t_key cindex;
+
+	pn = t->kv;
+	cindex = 0;
+
+	n = get_child_rcu(pn, cindex);
+	if (!n) {
+		trace_fib_table_lookup(tb->tb_id, flp, NULL, -EAGAIN);
+		return -EAGAIN;
+	}
+
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+	this_cpu_inc(stats->gets);
+#endif
+
+	/* Step 1: Travel to the longest prefix match in the trie */
+	for (;;) {
+		index = get_cindex(key, n);
+
+		/* This bit of code is a bit tricky but it combines multiple
+		 * checks into a single check.  The prefix consists of the
+		 * prefix plus zeros for the "bits" in the prefix. The index
+		 * is the difference between the key and this value.  From
+		 * this we can actually derive several pieces of data.
+		 *   if (index >= (1ul << bits))
+		 *     we have a mismatch in skip bits and failed
+		 *   else
+		 *     we know the value is cindex
+		 *
+		 * This check is safe even if bits == KEYLENGTH due to the
+		 * fact that we can only allocate a node with 32 bits if a
+		 * long is greater than 32 bits.
+		 */
+		if (index >= (1ul << n->bits))
+			break;
+
+		/* we have found a leaf. Prefixes have already been compared */
+		if (IS_LEAF(n))
+			goto found;
+
+		/* only record pn and cindex if we are going to be chopping
+		 * bits later.  Otherwise we are just wasting cycles.
+		 */
+		if (n->slen > n->pos) {
+			pn = n;
+			cindex = index;
+		}
+
+		n = get_child_rcu(n, index);
+		if (unlikely(!n))
+			goto backtrace;
+	}
+
+	/* Step 2: Sort out leaves and begin backtracing for longest prefix */
+	for (;;) {
+		/* record the pointer where our next node pointer is stored */
+		struct key_vector __rcu **cptr = n->tnode;
+
+		/* This test verifies that none of the bits that differ
+		 * between the key and the prefix exist in the region of
+		 * the lsb and higher in the prefix.
+		 */
+		if (unlikely(prefix_mismatch(key, n)) || (n->slen == n->pos))
+			goto backtrace;
+
+		/* exit out and process leaf */
+		if (unlikely(IS_LEAF(n)))
+			break;
+
+		/* Don't bother recording parent info.  Since we are in
+		 * prefix match mode we will have to come back to wherever
+		 * we started this traversal anyway
+		 */
+
+		while ((n = rcu_dereference(*cptr)) == NULL) {
+backtrace:
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+			if (!n)
+				this_cpu_inc(stats->null_node_hit);
+#endif
+			/* If we are at cindex 0 there are no more bits for
+			 * us to strip at this level so we must ascend back
+			 * up one level to see if there are any more bits to
+			 * be stripped there.
+			 */
+			while (!cindex) {
+				t_key pkey = pn->key;
+
+				/* If we don't have a parent then there is
+				 * nothing for us to do as we do not have any
+				 * further nodes to parse.
+				 */
+				if (IS_TRIE(pn)) {
+					trace_fib_table_lookup(tb->tb_id, flp,
+							       NULL, -EAGAIN);
+					return -EAGAIN;
+				}
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+				this_cpu_inc(stats->backtrack);
+#endif
+				/* Get Child's index */
+				pn = node_parent_rcu(pn);
+				cindex = get_index(pkey, pn);
+			}
+
+			/* strip the least significant bit from the cindex */
+			cindex &= cindex - 1;
+
+			/* grab pointer for next child node */
+			cptr = &pn->tnode[cindex];
+		}
+	}
+
+found:
+	/* this line carries forward the xor from earlier in the function */
+	index = key ^ n->key;
+
+	/* Step 3: Process the leaf, if that fails fall back to backtracing */
+	hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
+		struct fib_info *fi = fa->fa_info;
+		int nhsel, err;
+
+		if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) {
+			if (index >= (1ul << fa->fa_slen))
+				continue;
+		}
+		if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
+			continue;
+		if (fi->fib_dead)
+			continue;
+		if (fa->fa_info->fib_scope < flp->flowi4_scope)
+			continue;
+		fib_alias_accessed(fa);
+		err = fib_props[fa->fa_type].error;
+		if (unlikely(err < 0)) {
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+			this_cpu_inc(stats->semantic_match_passed);
+#endif
+			trace_fib_table_lookup(tb->tb_id, flp, NULL, err);
+			return err;
+		}
+		if (fi->fib_flags & RTNH_F_DEAD)
+			continue;
+		for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
+			const struct fib_nh *nh = &fi->fib_nh[nhsel];
+			struct in_device *in_dev = __in_dev_get_rcu(nh->nh_dev);
+
+			if (nh->nh_flags & RTNH_F_DEAD)
+				continue;
+			if (in_dev &&
+			    IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
+			    nh->nh_flags & RTNH_F_LINKDOWN &&
+			    !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
+				continue;
+			if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) {
+				if (flp->flowi4_oif &&
+				    flp->flowi4_oif != nh->nh_oif)
+					continue;
+			}
+
+			if (!(fib_flags & FIB_LOOKUP_NOREF))
+				refcount_inc(&fi->fib_clntref);
+
+			res->prefix = htonl(n->key);
+			res->prefixlen = KEYLENGTH - fa->fa_slen;
+			res->nh_sel = nhsel;
+			res->type = fa->fa_type;
+			res->scope = fi->fib_scope;
+			res->fi = fi;
+			res->table = tb;
+			res->fa_head = &n->leaf;
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+			this_cpu_inc(stats->semantic_match_passed);
+#endif
+			trace_fib_table_lookup(tb->tb_id, flp, nh, err);
+
+			return err;
+		}
+	}
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+	this_cpu_inc(stats->semantic_match_miss);
+#endif
+	goto backtrace;
+}
+EXPORT_SYMBOL_GPL(fib_table_lookup);
+
+static void fib_remove_alias(struct trie *t, struct key_vector *tp,
+			     struct key_vector *l, struct fib_alias *old)
+{
+	/* record the location of the previous list_info entry */
+	struct hlist_node **pprev = old->fa_list.pprev;
+	struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
+
+	/* remove the fib_alias from the list */
+	hlist_del_rcu(&old->fa_list);
+
+	/* if we emptied the list this leaf will be freed and we can sort
+	 * out parent suffix lengths as a part of trie_rebalance
+	 */
+	if (hlist_empty(&l->leaf)) {
+		if (tp->slen == l->slen)
+			node_pull_suffix(tp, tp->pos);
+		put_child_root(tp, l->key, NULL);
+		node_free(l);
+		trie_rebalance(t, tp);
+		return;
+	}
+
+	/* only access fa if it is pointing at the last valid hlist_node */
+	if (*pprev)
+		return;
+
+	/* update the trie with the latest suffix length */
+	l->slen = fa->fa_slen;
+	node_pull_suffix(tp, fa->fa_slen);
+}
+
+/* Caller must hold RTNL. */
+int fib_table_delete(struct net *net, struct fib_table *tb,
+		     struct fib_config *cfg, struct netlink_ext_ack *extack)
+{
+	struct trie *t = (struct trie *) tb->tb_data;
+	struct fib_alias *fa, *fa_to_delete;
+	struct key_vector *l, *tp;
+	u8 plen = cfg->fc_dst_len;
+	u8 slen = KEYLENGTH - plen;
+	u8 tos = cfg->fc_tos;
+	u32 key;
+
+	key = ntohl(cfg->fc_dst);
+
+	if (!fib_valid_key_len(key, plen, extack))
+		return -EINVAL;
+
+	l = fib_find_node(t, &tp, key);
+	if (!l)
+		return -ESRCH;
+
+	fa = fib_find_alias(&l->leaf, slen, tos, 0, tb->tb_id);
+	if (!fa)
+		return -ESRCH;
+
+	pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
+
+	fa_to_delete = NULL;
+	hlist_for_each_entry_from(fa, fa_list) {
+		struct fib_info *fi = fa->fa_info;
+
+		if ((fa->fa_slen != slen) ||
+		    (fa->tb_id != tb->tb_id) ||
+		    (fa->fa_tos != tos))
+			break;
+
+		if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
+		    (cfg->fc_scope == RT_SCOPE_NOWHERE ||
+		     fa->fa_info->fib_scope == cfg->fc_scope) &&
+		    (!cfg->fc_prefsrc ||
+		     fi->fib_prefsrc == cfg->fc_prefsrc) &&
+		    (!cfg->fc_protocol ||
+		     fi->fib_protocol == cfg->fc_protocol) &&
+		    fib_nh_match(cfg, fi, extack) == 0 &&
+		    fib_metrics_match(cfg, fi)) {
+			fa_to_delete = fa;
+			break;
+		}
+	}
+
+	if (!fa_to_delete)
+		return -ESRCH;
+
+	call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key, plen,
+				 fa_to_delete, extack);
+	rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
+		  &cfg->fc_nlinfo, 0);
+
+	if (!plen)
+		tb->tb_num_default--;
+
+	fib_remove_alias(t, tp, l, fa_to_delete);
+
+	if (fa_to_delete->fa_state & FA_S_ACCESSED)
+		rt_cache_flush(cfg->fc_nlinfo.nl_net);
+
+	fib_release_info(fa_to_delete->fa_info);
+	alias_free_mem_rcu(fa_to_delete);
+	return 0;
+}
+
+/* Scan for the next leaf starting at the provided key value */
+static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
+{
+	struct key_vector *pn, *n = *tn;
+	unsigned long cindex;
+
+	/* this loop is meant to try and find the key in the trie */
+	do {
+		/* record parent and next child index */
+		pn = n;
+		cindex = (key > pn->key) ? get_index(key, pn) : 0;
+
+		if (cindex >> pn->bits)
+			break;
+
+		/* descend into the next child */
+		n = get_child_rcu(pn, cindex++);
+		if (!n)
+			break;
+
+		/* guarantee forward progress on the keys */
+		if (IS_LEAF(n) && (n->key >= key))
+			goto found;
+	} while (IS_TNODE(n));
+
+	/* this loop will search for the next leaf with a greater key */
+	while (!IS_TRIE(pn)) {
+		/* if we exhausted the parent node we will need to climb */
+		if (cindex >= (1ul << pn->bits)) {
+			t_key pkey = pn->key;
+
+			pn = node_parent_rcu(pn);
+			cindex = get_index(pkey, pn) + 1;
+			continue;
+		}
+
+		/* grab the next available node */
+		n = get_child_rcu(pn, cindex++);
+		if (!n)
+			continue;
+
+		/* no need to compare keys since we bumped the index */
+		if (IS_LEAF(n))
+			goto found;
+
+		/* Rescan start scanning in new node */
+		pn = n;
+		cindex = 0;
+	}
+
+	*tn = pn;
+	return NULL; /* Root of trie */
+found:
+	/* if we are at the limit for keys just return NULL for the tnode */
+	*tn = pn;
+	return n;
+}
+
+static void fib_trie_free(struct fib_table *tb)
+{
+	struct trie *t = (struct trie *)tb->tb_data;
+	struct key_vector *pn = t->kv;
+	unsigned long cindex = 1;
+	struct hlist_node *tmp;
+	struct fib_alias *fa;
+
+	/* walk trie in reverse order and free everything */
+	for (;;) {
+		struct key_vector *n;
+
+		if (!(cindex--)) {
+			t_key pkey = pn->key;
+
+			if (IS_TRIE(pn))
+				break;
+
+			n = pn;
+			pn = node_parent(pn);
+
+			/* drop emptied tnode */
+			put_child_root(pn, n->key, NULL);
+			node_free(n);
+
+			cindex = get_index(pkey, pn);
+
+			continue;
+		}
+
+		/* grab the next available node */
+		n = get_child(pn, cindex);
+		if (!n)
+			continue;
+
+		if (IS_TNODE(n)) {
+			/* record pn and cindex for leaf walking */
+			pn = n;
+			cindex = 1ul << n->bits;
+
+			continue;
+		}
+
+		hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
+			hlist_del_rcu(&fa->fa_list);
+			alias_free_mem_rcu(fa);
+		}
+
+		put_child_root(pn, n->key, NULL);
+		node_free(n);
+	}
+
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+	free_percpu(t->stats);
+#endif
+	kfree(tb);
+}
+
+struct fib_table *fib_trie_unmerge(struct fib_table *oldtb)
+{
+	struct trie *ot = (struct trie *)oldtb->tb_data;
+	struct key_vector *l, *tp = ot->kv;
+	struct fib_table *local_tb;
+	struct fib_alias *fa;
+	struct trie *lt;
+	t_key key = 0;
+
+	if (oldtb->tb_data == oldtb->__data)
+		return oldtb;
+
+	local_tb = fib_trie_table(RT_TABLE_LOCAL, NULL);
+	if (!local_tb)
+		return NULL;
+
+	lt = (struct trie *)local_tb->tb_data;
+
+	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
+		struct key_vector *local_l = NULL, *local_tp;
+
+		hlist_for_each_entry(fa, &l->leaf, fa_list) {
+			struct fib_alias *new_fa;
+
+			if (local_tb->tb_id != fa->tb_id)
+				continue;
+
+			/* clone fa for new local table */
+			new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
+			if (!new_fa)
+				goto out;
+
+			memcpy(new_fa, fa, sizeof(*fa));
+
+			/* insert clone into table */
+			if (!local_l)
+				local_l = fib_find_node(lt, &local_tp, l->key);
+
+			if (fib_insert_alias(lt, local_tp, local_l, new_fa,
+					     NULL, l->key)) {
+				kmem_cache_free(fn_alias_kmem, new_fa);
+				goto out;
+			}
+		}
+
+		/* stop loop if key wrapped back to 0 */
+		key = l->key + 1;
+		if (key < l->key)
+			break;
+	}
+
+	return local_tb;
+out:
+	fib_trie_free(local_tb);
+
+	return NULL;
+}
+
+/* Caller must hold RTNL */
+void fib_table_flush_external(struct fib_table *tb)
+{
+	struct trie *t = (struct trie *)tb->tb_data;
+	struct key_vector *pn = t->kv;
+	unsigned long cindex = 1;
+	struct hlist_node *tmp;
+	struct fib_alias *fa;
+
+	/* walk trie in reverse order */
+	for (;;) {
+		unsigned char slen = 0;
+		struct key_vector *n;
+
+		if (!(cindex--)) {
+			t_key pkey = pn->key;
+
+			/* cannot resize the trie vector */
+			if (IS_TRIE(pn))
+				break;
+
+			/* update the suffix to address pulled leaves */
+			if (pn->slen > pn->pos)
+				update_suffix(pn);
+
+			/* resize completed node */
+			pn = resize(t, pn);
+			cindex = get_index(pkey, pn);
+
+			continue;
+		}
+
+		/* grab the next available node */
+		n = get_child(pn, cindex);
+		if (!n)
+			continue;
+
+		if (IS_TNODE(n)) {
+			/* record pn and cindex for leaf walking */
+			pn = n;
+			cindex = 1ul << n->bits;
+
+			continue;
+		}
+
+		hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
+			/* if alias was cloned to local then we just
+			 * need to remove the local copy from main
+			 */
+			if (tb->tb_id != fa->tb_id) {
+				hlist_del_rcu(&fa->fa_list);
+				alias_free_mem_rcu(fa);
+				continue;
+			}
+
+			/* record local slen */
+			slen = fa->fa_slen;
+		}
+
+		/* update leaf slen */
+		n->slen = slen;
+
+		if (hlist_empty(&n->leaf)) {
+			put_child_root(pn, n->key, NULL);
+			node_free(n);
+		}
+	}
+}
+
+/* Caller must hold RTNL. */
+int fib_table_flush(struct net *net, struct fib_table *tb, bool flush_all)
+{
+	struct trie *t = (struct trie *)tb->tb_data;
+	struct key_vector *pn = t->kv;
+	unsigned long cindex = 1;
+	struct hlist_node *tmp;
+	struct fib_alias *fa;
+	int found = 0;
+
+	/* walk trie in reverse order */
+	for (;;) {
+		unsigned char slen = 0;
+		struct key_vector *n;
+
+		if (!(cindex--)) {
+			t_key pkey = pn->key;
+
+			/* cannot resize the trie vector */
+			if (IS_TRIE(pn))
+				break;
+
+			/* update the suffix to address pulled leaves */
+			if (pn->slen > pn->pos)
+				update_suffix(pn);
+
+			/* resize completed node */
+			pn = resize(t, pn);
+			cindex = get_index(pkey, pn);
+
+			continue;
+		}
+
+		/* grab the next available node */
+		n = get_child(pn, cindex);
+		if (!n)
+			continue;
+
+		if (IS_TNODE(n)) {
+			/* record pn and cindex for leaf walking */
+			pn = n;
+			cindex = 1ul << n->bits;
+
+			continue;
+		}
+
+		hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
+			struct fib_info *fi = fa->fa_info;
+
+			if (!fi || tb->tb_id != fa->tb_id ||
+			    (!(fi->fib_flags & RTNH_F_DEAD) &&
+			     !fib_props[fa->fa_type].error)) {
+				slen = fa->fa_slen;
+				continue;
+			}
+
+			/* Do not flush error routes if network namespace is
+			 * not being dismantled
+			 */
+			if (!flush_all && fib_props[fa->fa_type].error) {
+				slen = fa->fa_slen;
+				continue;
+			}
+
+			call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
+						 n->key,
+						 KEYLENGTH - fa->fa_slen, fa,
+						 NULL);
+			hlist_del_rcu(&fa->fa_list);
+			fib_release_info(fa->fa_info);
+			alias_free_mem_rcu(fa);
+			found++;
+		}
+
+		/* update leaf slen */
+		n->slen = slen;
+
+		if (hlist_empty(&n->leaf)) {
+			put_child_root(pn, n->key, NULL);
+			node_free(n);
+		}
+	}
+
+	pr_debug("trie_flush found=%d\n", found);
+	return found;
+}
+
+static void fib_leaf_notify(struct net *net, struct key_vector *l,
+			    struct fib_table *tb, struct notifier_block *nb)
+{
+	struct fib_alias *fa;
+
+	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
+		struct fib_info *fi = fa->fa_info;
+
+		if (!fi)
+			continue;
+
+		/* local and main table can share the same trie,
+		 * so don't notify twice for the same entry.
+		 */
+		if (tb->tb_id != fa->tb_id)
+			continue;
+
+		call_fib_entry_notifier(nb, net, FIB_EVENT_ENTRY_ADD, l->key,
+					KEYLENGTH - fa->fa_slen, fa);
+	}
+}
+
+static void fib_table_notify(struct net *net, struct fib_table *tb,
+			     struct notifier_block *nb)
+{
+	struct trie *t = (struct trie *)tb->tb_data;
+	struct key_vector *l, *tp = t->kv;
+	t_key key = 0;
+
+	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
+		fib_leaf_notify(net, l, tb, nb);
+
+		key = l->key + 1;
+		/* stop in case of wrap around */
+		if (key < l->key)
+			break;
+	}
+}
+
+void fib_notify(struct net *net, struct notifier_block *nb)
+{
+	unsigned int h;
+
+	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
+		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
+		struct fib_table *tb;
+
+		hlist_for_each_entry_rcu(tb, head, tb_hlist)
+			fib_table_notify(net, tb, nb);
+	}
+}
+
+static void __trie_free_rcu(struct rcu_head *head)
+{
+	struct fib_table *tb = container_of(head, struct fib_table, rcu);
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+	struct trie *t = (struct trie *)tb->tb_data;
+
+	if (tb->tb_data == tb->__data)
+		free_percpu(t->stats);
+#endif /* CONFIG_IP_FIB_TRIE_STATS */
+	kfree(tb);
+}
+
+void fib_free_table(struct fib_table *tb)
+{
+	call_rcu(&tb->rcu, __trie_free_rcu);
+}
+
+static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
+			     struct sk_buff *skb, struct netlink_callback *cb)
+{
+	__be32 xkey = htonl(l->key);
+	struct fib_alias *fa;
+	int i, s_i;
+
+	s_i = cb->args[4];
+	i = 0;
+
+	/* rcu_read_lock is hold by caller */
+	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
+		int err;
+
+		if (i < s_i) {
+			i++;
+			continue;
+		}
+
+		if (tb->tb_id != fa->tb_id) {
+			i++;
+			continue;
+		}
+
+		err = fib_dump_info(skb, NETLINK_CB(cb->skb).portid,
+				    cb->nlh->nlmsg_seq, RTM_NEWROUTE,
+				    tb->tb_id, fa->fa_type,
+				    xkey, KEYLENGTH - fa->fa_slen,
+				    fa->fa_tos, fa->fa_info, NLM_F_MULTI);
+		if (err < 0) {
+			cb->args[4] = i;
+			return err;
+		}
+		i++;
+	}
+
+	cb->args[4] = i;
+	return skb->len;
+}
+
+/* rcu_read_lock needs to be hold by caller from readside */
+int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
+		   struct netlink_callback *cb)
+{
+	struct trie *t = (struct trie *)tb->tb_data;
+	struct key_vector *l, *tp = t->kv;
+	/* Dump starting at last key.
+	 * Note: 0.0.0.0/0 (ie default) is first key.
+	 */
+	int count = cb->args[2];
+	t_key key = cb->args[3];
+
+	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
+		int err;
+
+		err = fn_trie_dump_leaf(l, tb, skb, cb);
+		if (err < 0) {
+			cb->args[3] = key;
+			cb->args[2] = count;
+			return err;
+		}
+
+		++count;
+		key = l->key + 1;
+
+		memset(&cb->args[4], 0,
+		       sizeof(cb->args) - 4*sizeof(cb->args[0]));
+
+		/* stop loop if key wrapped back to 0 */
+		if (key < l->key)
+			break;
+	}
+
+	cb->args[3] = key;
+	cb->args[2] = count;
+
+	return skb->len;
+}
+
+void __init fib_trie_init(void)
+{
+	fn_alias_kmem = kmem_cache_create("ip_fib_alias",
+					  sizeof(struct fib_alias),
+					  0, SLAB_PANIC, NULL);
+
+	trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
+					   LEAF_SIZE,
+					   0, SLAB_PANIC, NULL);
+}
+
+struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
+{
+	struct fib_table *tb;
+	struct trie *t;
+	size_t sz = sizeof(*tb);
+
+	if (!alias)
+		sz += sizeof(struct trie);
+
+	tb = kzalloc(sz, GFP_KERNEL);
+	if (!tb)
+		return NULL;
+
+	tb->tb_id = id;
+	tb->tb_num_default = 0;
+	tb->tb_data = (alias ? alias->__data : tb->__data);
+
+	if (alias)
+		return tb;
+
+	t = (struct trie *) tb->tb_data;
+	t->kv[0].pos = KEYLENGTH;
+	t->kv[0].slen = KEYLENGTH;
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+	t->stats = alloc_percpu(struct trie_use_stats);
+	if (!t->stats) {
+		kfree(tb);
+		tb = NULL;
+	}
+#endif
+
+	return tb;
+}
+
+#ifdef CONFIG_PROC_FS
+/* Depth first Trie walk iterator */
+struct fib_trie_iter {
+	struct seq_net_private p;
+	struct fib_table *tb;
+	struct key_vector *tnode;
+	unsigned int index;
+	unsigned int depth;
+};
+
+static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
+{
+	unsigned long cindex = iter->index;
+	struct key_vector *pn = iter->tnode;
+	t_key pkey;
+
+	pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
+		 iter->tnode, iter->index, iter->depth);
+
+	while (!IS_TRIE(pn)) {
+		while (cindex < child_length(pn)) {
+			struct key_vector *n = get_child_rcu(pn, cindex++);
+
+			if (!n)
+				continue;
+
+			if (IS_LEAF(n)) {
+				iter->tnode = pn;
+				iter->index = cindex;
+			} else {
+				/* push down one level */
+				iter->tnode = n;
+				iter->index = 0;
+				++iter->depth;
+			}
+
+			return n;
+		}
+
+		/* Current node exhausted, pop back up */
+		pkey = pn->key;
+		pn = node_parent_rcu(pn);
+		cindex = get_index(pkey, pn) + 1;
+		--iter->depth;
+	}
+
+	/* record root node so further searches know we are done */
+	iter->tnode = pn;
+	iter->index = 0;
+
+	return NULL;
+}
+
+static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
+					     struct trie *t)
+{
+	struct key_vector *n, *pn;
+
+	if (!t)
+		return NULL;
+
+	pn = t->kv;
+	n = rcu_dereference(pn->tnode[0]);
+	if (!n)
+		return NULL;
+
+	if (IS_TNODE(n)) {
+		iter->tnode = n;
+		iter->index = 0;
+		iter->depth = 1;
+	} else {
+		iter->tnode = pn;
+		iter->index = 0;
+		iter->depth = 0;
+	}
+
+	return n;
+}
+
+static void trie_collect_stats(struct trie *t, struct trie_stat *s)
+{
+	struct key_vector *n;
+	struct fib_trie_iter iter;
+
+	memset(s, 0, sizeof(*s));
+
+	rcu_read_lock();
+	for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
+		if (IS_LEAF(n)) {
+			struct fib_alias *fa;
+
+			s->leaves++;
+			s->totdepth += iter.depth;
+			if (iter.depth > s->maxdepth)
+				s->maxdepth = iter.depth;
+
+			hlist_for_each_entry_rcu(fa, &n->leaf, fa_list)
+				++s->prefixes;
+		} else {
+			s->tnodes++;
+			if (n->bits < MAX_STAT_DEPTH)
+				s->nodesizes[n->bits]++;
+			s->nullpointers += tn_info(n)->empty_children;
+		}
+	}
+	rcu_read_unlock();
+}
+
+/*
+ *	This outputs /proc/net/fib_triestats
+ */
+static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
+{
+	unsigned int i, max, pointers, bytes, avdepth;
+
+	if (stat->leaves)
+		avdepth = stat->totdepth*100 / stat->leaves;
+	else
+		avdepth = 0;
+
+	seq_printf(seq, "\tAver depth:     %u.%02d\n",
+		   avdepth / 100, avdepth % 100);
+	seq_printf(seq, "\tMax depth:      %u\n", stat->maxdepth);
+
+	seq_printf(seq, "\tLeaves:         %u\n", stat->leaves);
+	bytes = LEAF_SIZE * stat->leaves;
+
+	seq_printf(seq, "\tPrefixes:       %u\n", stat->prefixes);
+	bytes += sizeof(struct fib_alias) * stat->prefixes;
+
+	seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
+	bytes += TNODE_SIZE(0) * stat->tnodes;
+
+	max = MAX_STAT_DEPTH;
+	while (max > 0 && stat->nodesizes[max-1] == 0)
+		max--;
+
+	pointers = 0;
+	for (i = 1; i < max; i++)
+		if (stat->nodesizes[i] != 0) {
+			seq_printf(seq, "  %u: %u",  i, stat->nodesizes[i]);
+			pointers += (1<<i) * stat->nodesizes[i];
+		}
+	seq_putc(seq, '\n');
+	seq_printf(seq, "\tPointers: %u\n", pointers);
+
+	bytes += sizeof(struct key_vector *) * pointers;
+	seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
+	seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
+}
+
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+static void trie_show_usage(struct seq_file *seq,
+			    const struct trie_use_stats __percpu *stats)
+{
+	struct trie_use_stats s = { 0 };
+	int cpu;
+
+	/* loop through all of the CPUs and gather up the stats */
+	for_each_possible_cpu(cpu) {
+		const struct trie_use_stats *pcpu = per_cpu_ptr(stats, cpu);
+
+		s.gets += pcpu->gets;
+		s.backtrack += pcpu->backtrack;
+		s.semantic_match_passed += pcpu->semantic_match_passed;
+		s.semantic_match_miss += pcpu->semantic_match_miss;
+		s.null_node_hit += pcpu->null_node_hit;
+		s.resize_node_skipped += pcpu->resize_node_skipped;
+	}
+
+	seq_printf(seq, "\nCounters:\n---------\n");
+	seq_printf(seq, "gets = %u\n", s.gets);
+	seq_printf(seq, "backtracks = %u\n", s.backtrack);
+	seq_printf(seq, "semantic match passed = %u\n",
+		   s.semantic_match_passed);
+	seq_printf(seq, "semantic match miss = %u\n", s.semantic_match_miss);
+	seq_printf(seq, "null node hit= %u\n", s.null_node_hit);
+	seq_printf(seq, "skipped node resize = %u\n\n", s.resize_node_skipped);
+}
+#endif /*  CONFIG_IP_FIB_TRIE_STATS */
+
+static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
+{
+	if (tb->tb_id == RT_TABLE_LOCAL)
+		seq_puts(seq, "Local:\n");
+	else if (tb->tb_id == RT_TABLE_MAIN)
+		seq_puts(seq, "Main:\n");
+	else
+		seq_printf(seq, "Id %d:\n", tb->tb_id);
+}
+
+
+static int fib_triestat_seq_show(struct seq_file *seq, void *v)
+{
+	struct net *net = (struct net *)seq->private;
+	unsigned int h;
+
+	seq_printf(seq,
+		   "Basic info: size of leaf:"
+		   " %zd bytes, size of tnode: %zd bytes.\n",
+		   LEAF_SIZE, TNODE_SIZE(0));
+
+	rcu_read_lock();
+	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
+		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
+		struct fib_table *tb;
+
+		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
+			struct trie *t = (struct trie *) tb->tb_data;
+			struct trie_stat stat;
+
+			if (!t)
+				continue;
+
+			fib_table_print(seq, tb);
+
+			trie_collect_stats(t, &stat);
+			trie_show_stats(seq, &stat);
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+			trie_show_usage(seq, t->stats);
+#endif
+		}
+		cond_resched_rcu();
+	}
+	rcu_read_unlock();
+
+	return 0;
+}
+
+static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
+{
+	struct fib_trie_iter *iter = seq->private;
+	struct net *net = seq_file_net(seq);
+	loff_t idx = 0;
+	unsigned int h;
+
+	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
+		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
+		struct fib_table *tb;
+
+		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
+			struct key_vector *n;
+
+			for (n = fib_trie_get_first(iter,
+						    (struct trie *) tb->tb_data);
+			     n; n = fib_trie_get_next(iter))
+				if (pos == idx++) {
+					iter->tb = tb;
+					return n;
+				}
+		}
+	}
+
+	return NULL;
+}
+
+static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU)
+{
+	rcu_read_lock();
+	return fib_trie_get_idx(seq, *pos);
+}
+
+static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct fib_trie_iter *iter = seq->private;
+	struct net *net = seq_file_net(seq);
+	struct fib_table *tb = iter->tb;
+	struct hlist_node *tb_node;
+	unsigned int h;
+	struct key_vector *n;
+
+	++*pos;
+	/* next node in same table */
+	n = fib_trie_get_next(iter);
+	if (n)
+		return n;
+
+	/* walk rest of this hash chain */
+	h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
+	while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
+		tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
+		n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
+		if (n)
+			goto found;
+	}
+
+	/* new hash chain */
+	while (++h < FIB_TABLE_HASHSZ) {
+		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
+		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
+			n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
+			if (n)
+				goto found;
+		}
+	}
+	return NULL;
+
+found:
+	iter->tb = tb;
+	return n;
+}
+
+static void fib_trie_seq_stop(struct seq_file *seq, void *v)
+	__releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+static void seq_indent(struct seq_file *seq, int n)
+{
+	while (n-- > 0)
+		seq_puts(seq, "   ");
+}
+
+static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
+{
+	switch (s) {
+	case RT_SCOPE_UNIVERSE: return "universe";
+	case RT_SCOPE_SITE:	return "site";
+	case RT_SCOPE_LINK:	return "link";
+	case RT_SCOPE_HOST:	return "host";
+	case RT_SCOPE_NOWHERE:	return "nowhere";
+	default:
+		snprintf(buf, len, "scope=%d", s);
+		return buf;
+	}
+}
+
+static const char *const rtn_type_names[__RTN_MAX] = {
+	[RTN_UNSPEC] = "UNSPEC",
+	[RTN_UNICAST] = "UNICAST",
+	[RTN_LOCAL] = "LOCAL",
+	[RTN_BROADCAST] = "BROADCAST",
+	[RTN_ANYCAST] = "ANYCAST",
+	[RTN_MULTICAST] = "MULTICAST",
+	[RTN_BLACKHOLE] = "BLACKHOLE",
+	[RTN_UNREACHABLE] = "UNREACHABLE",
+	[RTN_PROHIBIT] = "PROHIBIT",
+	[RTN_THROW] = "THROW",
+	[RTN_NAT] = "NAT",
+	[RTN_XRESOLVE] = "XRESOLVE",
+};
+
+static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
+{
+	if (t < __RTN_MAX && rtn_type_names[t])
+		return rtn_type_names[t];
+	snprintf(buf, len, "type %u", t);
+	return buf;
+}
+
+/* Pretty print the trie */
+static int fib_trie_seq_show(struct seq_file *seq, void *v)
+{
+	const struct fib_trie_iter *iter = seq->private;
+	struct key_vector *n = v;
+
+	if (IS_TRIE(node_parent_rcu(n)))
+		fib_table_print(seq, iter->tb);
+
+	if (IS_TNODE(n)) {
+		__be32 prf = htonl(n->key);
+
+		seq_indent(seq, iter->depth-1);
+		seq_printf(seq, "  +-- %pI4/%zu %u %u %u\n",
+			   &prf, KEYLENGTH - n->pos - n->bits, n->bits,
+			   tn_info(n)->full_children,
+			   tn_info(n)->empty_children);
+	} else {
+		__be32 val = htonl(n->key);
+		struct fib_alias *fa;
+
+		seq_indent(seq, iter->depth);
+		seq_printf(seq, "  |-- %pI4\n", &val);
+
+		hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
+			char buf1[32], buf2[32];
+
+			seq_indent(seq, iter->depth + 1);
+			seq_printf(seq, "  /%zu %s %s",
+				   KEYLENGTH - fa->fa_slen,
+				   rtn_scope(buf1, sizeof(buf1),
+					     fa->fa_info->fib_scope),
+				   rtn_type(buf2, sizeof(buf2),
+					    fa->fa_type));
+			if (fa->fa_tos)
+				seq_printf(seq, " tos=%d", fa->fa_tos);
+			seq_putc(seq, '\n');
+		}
+	}
+
+	return 0;
+}
+
+static const struct seq_operations fib_trie_seq_ops = {
+	.start  = fib_trie_seq_start,
+	.next   = fib_trie_seq_next,
+	.stop   = fib_trie_seq_stop,
+	.show   = fib_trie_seq_show,
+};
+
+struct fib_route_iter {
+	struct seq_net_private p;
+	struct fib_table *main_tb;
+	struct key_vector *tnode;
+	loff_t	pos;
+	t_key	key;
+};
+
+static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
+					    loff_t pos)
+{
+	struct key_vector *l, **tp = &iter->tnode;
+	t_key key;
+
+	/* use cached location of previously found key */
+	if (iter->pos > 0 && pos >= iter->pos) {
+		key = iter->key;
+	} else {
+		iter->pos = 1;
+		key = 0;
+	}
+
+	pos -= iter->pos;
+
+	while ((l = leaf_walk_rcu(tp, key)) && (pos-- > 0)) {
+		key = l->key + 1;
+		iter->pos++;
+		l = NULL;
+
+		/* handle unlikely case of a key wrap */
+		if (!key)
+			break;
+	}
+
+	if (l)
+		iter->key = l->key;	/* remember it */
+	else
+		iter->pos = 0;		/* forget it */
+
+	return l;
+}
+
+static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU)
+{
+	struct fib_route_iter *iter = seq->private;
+	struct fib_table *tb;
+	struct trie *t;
+
+	rcu_read_lock();
+
+	tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
+	if (!tb)
+		return NULL;
+
+	iter->main_tb = tb;
+	t = (struct trie *)tb->tb_data;
+	iter->tnode = t->kv;
+
+	if (*pos != 0)
+		return fib_route_get_idx(iter, *pos);
+
+	iter->pos = 0;
+	iter->key = KEY_MAX;
+
+	return SEQ_START_TOKEN;
+}
+
+static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct fib_route_iter *iter = seq->private;
+	struct key_vector *l = NULL;
+	t_key key = iter->key + 1;
+
+	++*pos;
+
+	/* only allow key of 0 for start of sequence */
+	if ((v == SEQ_START_TOKEN) || key)
+		l = leaf_walk_rcu(&iter->tnode, key);
+
+	if (l) {
+		iter->key = l->key;
+		iter->pos++;
+	} else {
+		iter->pos = 0;
+	}
+
+	return l;
+}
+
+static void fib_route_seq_stop(struct seq_file *seq, void *v)
+	__releases(RCU)
+{
+	rcu_read_unlock();
+}
+
+static unsigned int fib_flag_trans(int type, __be32 mask, const struct fib_info *fi)
+{
+	unsigned int flags = 0;
+
+	if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
+		flags = RTF_REJECT;
+	if (fi && fi->fib_nh->nh_gw)
+		flags |= RTF_GATEWAY;
+	if (mask == htonl(0xFFFFFFFF))
+		flags |= RTF_HOST;
+	flags |= RTF_UP;
+	return flags;
+}
+
+/*
+ *	This outputs /proc/net/route.
+ *	The format of the file is not supposed to be changed
+ *	and needs to be same as fib_hash output to avoid breaking
+ *	legacy utilities
+ */
+static int fib_route_seq_show(struct seq_file *seq, void *v)
+{
+	struct fib_route_iter *iter = seq->private;
+	struct fib_table *tb = iter->main_tb;
+	struct fib_alias *fa;
+	struct key_vector *l = v;
+	__be32 prefix;
+
+	if (v == SEQ_START_TOKEN) {
+		seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
+			   "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
+			   "\tWindow\tIRTT");
+		return 0;
+	}
+
+	prefix = htonl(l->key);
+
+	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
+		const struct fib_info *fi = fa->fa_info;
+		__be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
+		unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
+
+		if ((fa->fa_type == RTN_BROADCAST) ||
+		    (fa->fa_type == RTN_MULTICAST))
+			continue;
+
+		if (fa->tb_id != tb->tb_id)
+			continue;
+
+		seq_setwidth(seq, 127);
+
+		if (fi)
+			seq_printf(seq,
+				   "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
+				   "%d\t%08X\t%d\t%u\t%u",
+				   fi->fib_dev ? fi->fib_dev->name : "*",
+				   prefix,
+				   fi->fib_nh->nh_gw, flags, 0, 0,
+				   fi->fib_priority,
+				   mask,
+				   (fi->fib_advmss ?
+				    fi->fib_advmss + 40 : 0),
+				   fi->fib_window,
+				   fi->fib_rtt >> 3);
+		else
+			seq_printf(seq,
+				   "*\t%08X\t%08X\t%04X\t%d\t%u\t"
+				   "%d\t%08X\t%d\t%u\t%u",
+				   prefix, 0, flags, 0, 0, 0,
+				   mask, 0, 0, 0);
+
+		seq_pad(seq, '\n');
+	}
+
+	return 0;
+}
+
+static const struct seq_operations fib_route_seq_ops = {
+	.start  = fib_route_seq_start,
+	.next   = fib_route_seq_next,
+	.stop   = fib_route_seq_stop,
+	.show   = fib_route_seq_show,
+};
+
+int __net_init fib_proc_init(struct net *net)
+{
+	if (!proc_create_net("fib_trie", 0444, net->proc_net, &fib_trie_seq_ops,
+			sizeof(struct fib_trie_iter)))
+		goto out1;
+
+	if (!proc_create_net_single("fib_triestat", 0444, net->proc_net,
+			fib_triestat_seq_show, NULL))
+		goto out2;
+
+	if (!proc_create_net("route", 0444, net->proc_net, &fib_route_seq_ops,
+			sizeof(struct fib_route_iter)))
+		goto out3;
+
+	return 0;
+
+out3:
+	remove_proc_entry("fib_triestat", net->proc_net);
+out2:
+	remove_proc_entry("fib_trie", net->proc_net);
+out1:
+	return -ENOMEM;
+}
+
+void __net_exit fib_proc_exit(struct net *net)
+{
+	remove_proc_entry("fib_trie", net->proc_net);
+	remove_proc_entry("fib_triestat", net->proc_net);
+	remove_proc_entry("route", net->proc_net);
+}
+
+#endif /* CONFIG_PROC_FS */