[IPV4]: Add LC-Trie FIB lookup algorithm.
Robert Olsson [Tue, 21 Jun 2005 19:43:18 +0000 (12:43 -0700)]
Signed-off-by: Robert Olsson <Robert.Olsson@data.slu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/Kconfig
net/ipv4/Makefile
net/ipv4/af_inet.c
net/ipv4/fib_trie.c [new file with mode: 0644]

index 6d3e8b1..05107e0 100644 (file)
@@ -1,6 +1,32 @@
 #
 # IP configuration
 #
+choice 
+       prompt "Choose IP: FIB lookup""
+       depends on INET
+       default IP_FIB_HASH
+
+config IP_FIB_HASH
+       bool "FIB_HASH"
+       ---help---
+       Current FIB is very proven and good enough for most users.
+
+config IP_FIB_TRIE
+       bool "FIB_TRIE"
+       ---help---
+       Use new experimental LC-trie as FIB lookup algoritm. 
+        This improves lookup performance
+       
+       LC-trie is described in:
+       
+       IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
+       IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
+       An experimental study of compression methods for dynamic tries
+       Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
+       http://www.nada.kth.se/~snilsson/public/papers/dyntrie2/
+       
+endchoice
+
 config IP_MULTICAST
        bool "IP: multicasting"
        depends on INET
index 8b37962..65d57d8 100644 (file)
@@ -7,8 +7,10 @@ obj-y     := utils.o route.o inetpeer.o protocol.o \
             ip_output.o ip_sockglue.o \
             tcp.o tcp_input.o tcp_output.o tcp_timer.o tcp_ipv4.o tcp_minisocks.o \
             datagram.o raw.o udp.o arp.o icmp.o devinet.o af_inet.o igmp.o \
-            sysctl_net_ipv4.o fib_frontend.o fib_semantics.o fib_hash.o
+            sysctl_net_ipv4.o fib_frontend.o fib_semantics.o
 
+obj-$(CONFIG_IP_FIB_HASH) += fib_hash.o
+obj-$(CONFIG_IP_FIB_TRIE) += fib_trie.o
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_IP_MULTIPLE_TABLES) += fib_rules.o
 obj-$(CONFIG_IP_MROUTE) += ipmr.o
index 03942f1..658e797 100644 (file)
@@ -1119,6 +1119,10 @@ module_init(inet_init);
 #ifdef CONFIG_PROC_FS
 extern int  fib_proc_init(void);
 extern void fib_proc_exit(void);
+#ifdef CONFIG_IP_FIB_TRIE
+extern int  fib_stat_proc_init(void);
+extern void fib_stat_proc_exit(void);
+#endif
 extern int  ip_misc_proc_init(void);
 extern int  raw_proc_init(void);
 extern void raw_proc_exit(void);
@@ -1139,11 +1143,19 @@ static int __init ipv4_proc_init(void)
                goto out_udp;
        if (fib_proc_init())
                goto out_fib;
+#ifdef CONFIG_IP_FIB_TRIE
+         if (fib_stat_proc_init())
+                 goto out_fib_stat;
+ #endif
        if (ip_misc_proc_init())
                goto out_misc;
 out:
        return rc;
 out_misc:
+#ifdef CONFIG_IP_FIB_TRIE
+       fib_stat_proc_exit();
+out_fib_stat:
+#endif
        fib_proc_exit();
 out_fib:
        udp4_proc_exit();
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
new file mode 100644 (file)
index 0000000..c0ece94
--- /dev/null
@@ -0,0 +1,2454 @@
+/*
+ *   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 descibed in:
+ * 
+ * An experimental study of compression methods for dynamic tries
+ * Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
+ * http://www.nada.kth.se/~snilsson/public/papers/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
+ *
+ * Version:    $Id: fib_trie.c,v 1.3 2005/06/08 14:20:01 robert Exp $
+ *
+ *
+ * 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.
+ */
+
+#define VERSION "0.323"
+
+#include <linux/config.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+#include <asm/bitops.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.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/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/proc_fs.h>
+#include <linux/skbuff.h>
+#include <linux/netlink.h>
+#include <linux/init.h>
+#include <linux/list.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 "fib_lookup.h"
+
+#undef CONFIG_IP_FIB_TRIE_STATS
+#define MAX_CHILDS 16384
+
+#define EXTRACT(p, n, str) ((str)<<(p)>>(32-(n)))
+#define KEYLENGTH (8*sizeof(t_key))
+#define MASK_PFX(k, l) (((l)==0)?0:(k >> (KEYLENGTH-l)) << (KEYLENGTH-l))
+#define TKEY_GET_MASK(offset, bits) (((bits)==0)?0:((t_key)(-1) << (KEYLENGTH - bits) >> offset))
+
+static DEFINE_RWLOCK(fib_lock);
+
+typedef unsigned int t_key;
+
+#define T_TNODE 0
+#define T_LEAF  1
+#define NODE_TYPE_MASK 0x1UL
+#define NODE_PARENT(_node) \
+((struct tnode *)((_node)->_parent & ~NODE_TYPE_MASK))
+#define NODE_SET_PARENT(_node, _ptr) \
+((_node)->_parent = (((unsigned long)(_ptr)) | \
+                     ((_node)->_parent & NODE_TYPE_MASK)))
+#define NODE_INIT_PARENT(_node, _type) \
+((_node)->_parent = (_type))
+#define NODE_TYPE(_node) \
+((_node)->_parent & NODE_TYPE_MASK)
+
+#define IS_TNODE(n) (!(n->_parent & T_LEAF))
+#define IS_LEAF(n) (n->_parent & T_LEAF)
+
+struct node {
+        t_key key;
+       unsigned long _parent;
+};
+
+struct leaf {
+        t_key key;
+       unsigned long _parent;
+       struct hlist_head list;
+};
+
+struct leaf_info {
+       struct hlist_node hlist;
+       int plen;
+       struct list_head falh;
+};
+
+struct tnode {
+        t_key key;
+       unsigned long _parent;
+        unsigned short pos:5;        /* 2log(KEYLENGTH) bits needed */
+        unsigned short bits:5;       /* 2log(KEYLENGTH) bits needed */
+        unsigned short full_children;  /* KEYLENGTH bits needed */
+        unsigned short empty_children; /* KEYLENGTH bits needed */
+        struct node *child[0];
+};
+
+#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;
+};
+#endif
+
+struct trie_stat {
+       unsigned int totdepth;
+       unsigned int maxdepth;
+       unsigned int tnodes;
+       unsigned int leaves;
+       unsigned int nullpointers;
+       unsigned int nodesizes[MAX_CHILDS];
+};    
+
+struct trie {
+        struct node *trie;
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+       struct trie_use_stats stats;
+#endif
+        int size;
+       unsigned int revision;
+};
+
+static int trie_debug = 0;
+
+static int tnode_full(struct tnode *tn, struct node *n);
+static void put_child(struct trie *t, struct tnode *tn, int i, struct node *n);
+static void tnode_put_child_reorg(struct tnode *tn, int i, struct node *n, int wasfull);
+static int tnode_child_length(struct tnode *tn);
+static struct node *resize(struct trie *t, struct tnode *tn);
+static struct tnode *inflate(struct trie *t, struct tnode *tn);
+static struct tnode *halve(struct trie *t, struct tnode *tn);
+static void tnode_free(struct tnode *tn);
+static void trie_dump_seq(struct seq_file *seq, struct trie *t);
+extern struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio);
+extern int fib_detect_death(struct fib_info *fi, int order,
+                            struct fib_info **last_resort, int *last_idx, int *dflt);
+
+extern void rtmsg_fib(int event, u32 key, struct fib_alias *fa, int z, int tb_id,
+               struct nlmsghdr *n, struct netlink_skb_parms *req);
+
+static kmem_cache_t *fn_alias_kmem;
+static struct trie *trie_local = NULL, *trie_main = NULL;
+
+static void trie_bug(char *err)
+{
+       printk("Trie Bug: %s\n", err);
+       BUG();
+}
+
+static inline struct node *tnode_get_child(struct tnode *tn, int i) 
+{
+        if (i >=  1<<tn->bits) 
+                trie_bug("tnode_get_child");
+
+        return tn->child[i];
+}
+
+static inline int tnode_child_length(struct tnode *tn)
+{
+        return 1<<tn->bits;
+}
+
+/*
+  _________________________________________________________________
+  | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
+  ----------------------------------------------------------------
+    0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15 
+
+  _________________________________________________________________
+  | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
+  -----------------------------------------------------------------
+   16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31
+
+  tp->pos = 7
+  tp->bits = 3
+  n->pos = 15
+  n->bits=4
+  KEYLENGTH=32
+*/
+
+static inline t_key tkey_extract_bits(t_key a, int offset, int bits)
+{
+        if (offset < KEYLENGTH)
+               return ((t_key)(a << offset)) >> (KEYLENGTH - bits);
+        else
+               return 0;
+}
+
+static inline int tkey_equals(t_key a, t_key b)
+{
+  return a == b;
+}
+
+static inline int tkey_sub_equals(t_key a, int offset, int bits, t_key b)
+{
+     if (bits == 0 || offset >= KEYLENGTH)
+            return 1;
+        bits = bits > KEYLENGTH ? KEYLENGTH : bits;
+        return ((a ^ b) << offset) >> (KEYLENGTH - bits) == 0;
+}      
+
+static inline int tkey_mismatch(t_key a, int offset, t_key b)
+{
+       t_key diff = a ^ b;
+       int i = offset;
+
+       if(!diff) 
+         return 0;
+       while((diff << i) >> (KEYLENGTH-1) == 0)
+               i++;
+       return i;
+}
+
+/* Candiate for fib_semantics */
+
+static void fn_free_alias(struct fib_alias *fa)
+{
+       fib_release_info(fa->fa_info);
+       kmem_cache_free(fn_alias_kmem, fa);
+}
+
+/*
+  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 
+  necessitaded 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 - note the 
+  call to tkey_sub_equals() in trie_insert().
+
+  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 |
+  -----------------------------------------------------------------
+    0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15 
+
+  _________________________________________________________________
+  | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
+  -----------------------------------------------------------------
+   16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31
+
+  tp->pos = 7
+  tp->bits = 3
+  n->pos = 15
+  n->bits=4
+
+  First, let's just ignore the bits that come before the parent tp, that is 
+  the bits from 0 to (tp->pos-1). 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 (tp->pos + tp->bits) to (n->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 (n->pos + n->bits) onward, are completely unknown
+  at this point.
+
+*/
+
+static void check_tnode(struct tnode *tn)
+{
+       if(tn && tn->pos+tn->bits > 32) {
+               printk("TNODE ERROR tn=%p, pos=%d, bits=%d\n", tn, tn->pos, tn->bits);
+       }
+}
+
+static int halve_threshold = 25;
+static int inflate_threshold = 50;
+
+static struct leaf *leaf_new(void)
+{
+       struct leaf *l = kmalloc(sizeof(struct leaf),  GFP_KERNEL);
+       if(l) {
+               NODE_INIT_PARENT(l, T_LEAF);
+               INIT_HLIST_HEAD(&l->list);
+       }
+       return l;
+}
+
+static struct leaf_info *leaf_info_new(int plen)
+{
+       struct leaf_info *li = kmalloc(sizeof(struct leaf_info),  GFP_KERNEL);
+       li->plen = plen;
+       INIT_LIST_HEAD(&li->falh);
+       return li;
+}
+
+static inline void free_leaf(struct leaf *l)
+{
+       kfree(l);
+}
+
+static inline void free_leaf_info(struct leaf_info *li)
+{
+       kfree(li);
+}
+
+static struct tnode* tnode_new(t_key key, int pos, int bits)
+{
+       int nchildren = 1<<bits;
+       int sz = sizeof(struct tnode) + nchildren * sizeof(struct node *);
+       struct tnode *tn = kmalloc(sz,  GFP_KERNEL);
+
+       if(tn)  {
+               memset(tn, 0, sz);
+               NODE_INIT_PARENT(tn, T_TNODE);
+               tn->pos = pos;
+               tn->bits = bits;
+               tn->key = key;
+               tn->full_children = 0;
+               tn->empty_children = 1<<bits;
+       }
+       if(trie_debug > 0) 
+               printk("AT %p s=%u %u\n", tn, (unsigned int) sizeof(struct tnode),
+                      (unsigned int) (sizeof(struct node) * 1<<bits));
+       return tn;
+}
+
+static void tnode_free(struct tnode *tn)
+{
+       if(!tn) {
+               trie_bug("tnode_free\n");
+       }
+       if(IS_LEAF(tn)) {
+               free_leaf((struct leaf *)tn);
+               if(trie_debug > 0 ) 
+                       printk("FL %p \n", tn);
+       }
+       else if(IS_TNODE(tn)) { 
+               kfree(tn);
+               if(trie_debug > 0 ) 
+                       printk("FT %p \n", tn);
+       }
+       else {
+               trie_bug("tnode_free\n");
+       }
+}
+
+/*
+ * 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 tnode *tn, struct node *n)
+{
+       if(n == NULL || IS_LEAF(n))
+               return 0;
+
+       return ((struct tnode *) n)->pos == tn->pos + tn->bits;
+}
+
+static inline void put_child(struct trie *t, struct tnode *tn, int i, struct node *n) 
+{
+       tnode_put_child_reorg(tn, i, n, -1);
+}
+
+ /* 
+  * Add a child at position i overwriting the old value.
+  * Update the value of full_children and empty_children.
+  */
+
+static void tnode_put_child_reorg(struct tnode *tn, int i, struct node *n, int wasfull) 
+{
+       struct node *chi;
+       int isfull;
+
+       if(i >=  1<<tn->bits) {
+               printk("bits=%d, i=%d\n", tn->bits, i);
+               trie_bug("tnode_put_child_reorg bits");
+       }
+       write_lock_bh(&fib_lock);
+       chi = tn->child[i];     
+
+       /* update emptyChildren */
+       if (n == NULL && chi != NULL)
+               tn->empty_children++;
+       else if (n != NULL && chi == NULL)
+               tn->empty_children--;
+  
+       /* update fullChildren */
+        if (wasfull == -1)
+               wasfull = tnode_full(tn, chi);
+
+       isfull = tnode_full(tn, n);
+       if (wasfull && !isfull) 
+               tn->full_children--;
+       
+       else if (!wasfull && isfull) 
+               tn->full_children++;
+       if(n) 
+               NODE_SET_PARENT(n, tn); 
+
+       tn->child[i] = n;
+       write_unlock_bh(&fib_lock);
+}
+
+static struct node *resize(struct trie *t, struct tnode *tn) 
+{
+       int i;
+
+       if (!tn)
+               return NULL;
+
+       if(trie_debug) 
+               printk("In tnode_resize %p inflate_threshold=%d threshold=%d\n", 
+                     tn, inflate_threshold, halve_threshold);
+
+       /* No children */
+       if (tn->empty_children == tnode_child_length(tn)) {
+               tnode_free(tn);
+               return NULL;
+       }
+       /* One child */
+       if (tn->empty_children == tnode_child_length(tn) - 1)
+               for (i = 0; i < tnode_child_length(tn); i++) {
+
+                       write_lock_bh(&fib_lock);
+                       if (tn->child[i] != NULL) {
+
+                               /* compress one level */
+                               struct node *n = tn->child[i];
+                               if(n)
+                                       NODE_INIT_PARENT(n, NODE_TYPE(n));
+
+                               write_unlock_bh(&fib_lock);
+                               tnode_free(tn);
+                               return n;
+                       }
+                       write_unlock_bh(&fib_lock);
+               }
+       /* 
+        * Double as long as the resulting node has a number of
+        * nonempty nodes that are above the threshold.
+        */
+
+       /*
+        * 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 
+        * tnode_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: tnode_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 = tnode_child_length(tn) - tn->empty_children - 
+        *     tn->full_children;
+        *
+        * new_child_length = tnode_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 * (tnode_child_length(tn) - tn->empty_children + 
+        *    tn->full_children ) >= inflate_threshold * new_child_length
+        * 
+        * expand new_child_length:
+        * 100 * (tnode_child_length(tn) - tn->empty_children + 
+        *    tn->full_children ) >=
+        *      inflate_threshold * tnode_child_length(tn) * 2
+        * 
+        * shorten again:
+        * 50 * (tn->full_children + tnode_child_length(tn) - 
+        *    tn->empty_children ) >= inflate_threshold * 
+        *    tnode_child_length(tn)
+        * 
+        */
+
+       check_tnode(tn);
+
+       while ((tn->full_children > 0 &&
+              50 * (tn->full_children + tnode_child_length(tn) - tn->empty_children) >=
+                               inflate_threshold * tnode_child_length(tn))) {
+
+               tn = inflate(t, tn);
+       }
+
+       check_tnode(tn);
+
+       /*
+        * Halve as long as the number of empty children in this
+        * node is above threshold.
+        */
+       while (tn->bits > 1 &&
+              100 * (tnode_child_length(tn) - tn->empty_children) <
+              halve_threshold * tnode_child_length(tn))
+
+               tn = halve(t, tn);
+  
+       /* Only one child remains */
+
+       if (tn->empty_children == tnode_child_length(tn) - 1)
+               for (i = 0; i < tnode_child_length(tn); i++) {
+                       
+                       write_lock_bh(&fib_lock);
+                       if (tn->child[i] != NULL) {
+                               /* compress one level */
+                               struct node *n = tn->child[i];
+
+                               if(n)
+                                       NODE_INIT_PARENT(n, NODE_TYPE(n));
+
+                               write_unlock_bh(&fib_lock);
+                               tnode_free(tn);
+                               return n;
+                       }
+                       write_unlock_bh(&fib_lock);
+               }
+
+       return (struct node *) tn;
+}
+
+static struct tnode *inflate(struct trie *t, struct tnode *tn)
+{
+       struct tnode *inode;
+       struct tnode *oldtnode = tn;
+       int olen = tnode_child_length(tn);
+       int i;
+
+       if(trie_debug) 
+               printk("In inflate\n");
+
+       tn = tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits + 1);
+
+       if (!tn)
+               trie_bug("tnode_new failed");
+
+       for(i = 0; i < olen; i++) {
+               struct node *node = tnode_get_child(oldtnode, i);
+      
+               /* An empty child */
+               if (node == NULL)
+                       continue;
+
+               /* A leaf or an internal node with skipped bits */
+
+               if(IS_LEAF(node) || ((struct tnode *) node)->pos >
+                  tn->pos + tn->bits - 1) {
+                       if(tkey_extract_bits(node->key, tn->pos + tn->bits - 1,
+                                            1) == 0)
+                               put_child(t, tn, 2*i, node);
+                       else
+                               put_child(t, tn, 2*i+1, node);
+                       continue;
+               }
+
+               /* An internal node with two children */
+               inode = (struct tnode *) node;
+
+               if (inode->bits == 1) {
+                       put_child(t, tn, 2*i, inode->child[0]);
+                       put_child(t, tn, 2*i+1, inode->child[1]);
+
+                       tnode_free(inode);
+               }
+
+                       /* An internal node with more than two children */
+               else {
+                       struct tnode *left, *right;
+                       int size, j;
+
+                       /* We will replace this node 'inode' with two new 
+                        * ones, 'left' and 'right', 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 
+                        * left's key and "1" in right's key. Since we are 
+                        * moving the key position by one step, the bit that 
+                        * we are moving away from - the bit at position 
+                        * (inode->pos) - is the one that will differ between 
+                        * left and right. So... we synthesize that bit in the
+                        * two  new keys.
+                        * The mask 'm' below will be a single "one" bit at 
+                        * the position (inode->pos)
+                        */
+
+                       t_key m = TKEY_GET_MASK(inode->pos, 1);
+                       /* Use the old key, but set the new significant 
+                        *   bit to zero. 
+                        */
+                       left = tnode_new(inode->key&(~m), inode->pos + 1,
+                                        inode->bits - 1);
+
+                       if(!left) 
+                               trie_bug("tnode_new failed");
+                       
+                       
+                       /* Use the old key, but set the new significant 
+                        * bit to one. 
+                        */
+                       right = tnode_new(inode->key|m, inode->pos + 1,
+                                         inode->bits - 1);
+
+                       if(!right) 
+                               trie_bug("tnode_new failed");
+                       
+                       size = tnode_child_length(left);
+                       for(j = 0; j < size; j++) {
+                               put_child(t, left, j, inode->child[j]);
+                               put_child(t, right, j, inode->child[j + size]);
+                       }
+                       put_child(t, tn, 2*i, resize(t, left));
+                       put_child(t, tn, 2*i+1, resize(t, right));
+
+                       tnode_free(inode);
+               }
+       }
+       tnode_free(oldtnode);
+       return tn;
+}
+
+static struct tnode *halve(struct trie *t, struct tnode *tn)
+{
+       struct tnode *oldtnode = tn;
+       struct node *left, *right;
+       int i;
+       int olen = tnode_child_length(tn);
+
+       if(trie_debug) printk("In halve\n");
+  
+       tn=tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits - 1);
+
+       if(!tn) 
+               trie_bug("tnode_new failed");
+
+       for(i = 0; i < olen; i += 2) {
+               left = tnode_get_child(oldtnode, i);
+               right = tnode_get_child(oldtnode, i+1);
+    
+               /* At least one of the children is empty */
+               if (left == NULL) {
+                       if (right == NULL)    /* Both are empty */
+                               continue;
+                       put_child(t, tn, i/2, right);
+               } else if (right == NULL)
+                       put_child(t, tn, i/2, left);
+     
+               /* Two nonempty children */
+               else {
+                       struct tnode *newBinNode =
+                               tnode_new(left->key, tn->pos + tn->bits, 1);
+
+                       if(!newBinNode) 
+                               trie_bug("tnode_new failed");
+
+                       put_child(t, newBinNode, 0, left);
+                       put_child(t, newBinNode, 1, right);
+                       put_child(t, tn, i/2, resize(t, newBinNode));
+               }
+       }
+       tnode_free(oldtnode);
+       return tn;
+}
+
+static void *trie_init(struct trie *t)
+{
+       if(t) {
+               t->size = 0;
+               t->trie = NULL;
+               t->revision = 0;
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+                       memset(&t->stats, 0, sizeof(struct trie_use_stats));
+#endif
+       }
+       return t;
+}
+
+static struct leaf_info *find_leaf_info(struct hlist_head *head, int plen)
+{
+       struct hlist_node *node;
+       struct leaf_info *li;
+
+       hlist_for_each_entry(li, node, head, hlist) {
+                 
+               if ( li->plen == plen )
+                       return li;
+       }
+       return NULL;
+}
+
+static inline struct list_head * get_fa_head(struct leaf *l, int plen)
+{
+       struct list_head *fa_head=NULL;
+       struct leaf_info *li = find_leaf_info(&l->list, plen);
+       
+       if(li) 
+               fa_head = &li->falh;
+       
+       return fa_head;
+}
+
+static void insert_leaf_info(struct hlist_head *head, struct leaf_info *new)
+{
+       struct leaf_info *li=NULL, *last=NULL;
+       struct hlist_node *node, *tmp;
+
+       write_lock_bh(&fib_lock);
+       
+       if(hlist_empty(head))
+               hlist_add_head(&new->hlist, head);
+       else {
+               hlist_for_each_entry_safe(li, node, tmp, head, hlist) {
+                       
+                       if (new->plen > li->plen) 
+                               break;
+                       
+                       last = li;
+               }
+               if(last) 
+                       hlist_add_after(&last->hlist, &new->hlist);
+               else 
+                       hlist_add_before(&new->hlist, &li->hlist);
+       }
+       write_unlock_bh(&fib_lock);
+}
+
+static struct leaf *
+fib_find_node(struct trie *t, u32 key)
+{
+       int pos;
+       struct tnode *tn;
+       struct node *n;
+
+       pos = 0;
+       n=t->trie;
+
+       while (n != NULL &&  NODE_TYPE(n) == T_TNODE) {
+               tn = (struct tnode *) n;
+                       
+               check_tnode(tn);
+                       
+               if(tkey_sub_equals(tn->key, pos, tn->pos-pos, key)) {
+                       pos=tn->pos + tn->bits;
+                       n = tnode_get_child(tn, tkey_extract_bits(key, tn->pos, tn->bits));
+               }
+               else
+                       break;
+       }
+       /* Case we have found a leaf. Compare prefixes */
+
+       if (n != NULL && IS_LEAF(n) && tkey_equals(key, n->key)) {
+               struct leaf *l = (struct leaf *) n;
+               return l;
+       }
+       return NULL;
+}
+
+static struct node *trie_rebalance(struct trie *t, struct tnode *tn)
+{
+       int i = 0;
+       int wasfull;
+       t_key cindex, key;
+       struct tnode *tp = NULL;
+
+       if(!tn) 
+               BUG();
+       
+       key = tn->key;
+       i = 0;
+
+       while (tn != NULL && NODE_PARENT(tn) != NULL) {
+
+               if( i > 10 ) {
+                       printk("Rebalance tn=%p \n", tn);
+                       if(tn)          printk("tn->parent=%p \n", NODE_PARENT(tn));
+                       
+                       printk("Rebalance tp=%p \n", tp);
+                       if(tp)          printk("tp->parent=%p \n", NODE_PARENT(tp));
+               }
+
+               if( i > 12 ) BUG();
+               i++;
+
+               tp = NODE_PARENT(tn);
+               cindex = tkey_extract_bits(key, tp->pos, tp->bits);
+               wasfull = tnode_full(tp, tnode_get_child(tp, cindex));
+               tn = (struct tnode *) resize (t, (struct tnode *)tn);
+               tnode_put_child_reorg((struct tnode *)tp, cindex,(struct node*)tn, wasfull);
+               
+               if(!NODE_PARENT(tn))
+                       break;
+
+               tn = NODE_PARENT(tn);
+       }
+       /* Handle last (top) tnode */
+       if (IS_TNODE(tn)) 
+               tn = (struct tnode*) resize(t, (struct tnode *)tn);
+
+       return (struct node*) tn;
+}
+
+static struct list_head *
+fib_insert_node(struct trie *t, u32 key, int plen)
+{
+       int pos, newpos;
+       struct tnode *tp = NULL, *tn = NULL;
+       struct node *n;
+       struct leaf *l;
+       int missbit;
+       struct list_head *fa_head=NULL;
+       struct leaf_info *li;
+       t_key cindex;
+
+       pos = 0;
+       n=t->trie;
+
+       /* If we point to NULL, stop. Either the tree is empty and we should 
+        * just put a new leaf in if, or we have reached an empty child slot, 
+        * and we should just put our new leaf in that.
+        * If we point to a T_TNODE, check if it matches our key. Note that 
+        * a T_TNODE might be skipping any number of bits - its 'pos' need 
+        * not be the parent's 'pos'+'bits'!
+        *
+        * If it does match the current key, get pos/bits from it, extract 
+        * the index from our key, push the T_TNODE and walk the tree.
+        *
+        * If it doesn't, we have to replace it with a new T_TNODE.
+        *
+        * If we point to a T_LEAF, it might or might not have the same key 
+        * as we do. If it does, just change the value, update the T_LEAF's 
+        * value, and return it. 
+        * If it doesn't, we need to replace it with a T_TNODE.
+        */
+
+       while (n != NULL &&  NODE_TYPE(n) == T_TNODE) {
+               tn = (struct tnode *) n;
+                       
+               check_tnode(tn);
+               
+               if(tkey_sub_equals(tn->key, pos, tn->pos-pos, key)) {
+                       tp = tn;
+                       pos=tn->pos + tn->bits;
+                       n = tnode_get_child(tn, tkey_extract_bits(key, tn->pos, tn->bits));
+
+                       if(n && NODE_PARENT(n) != tn) {
+                               printk("BUG tn=%p, n->parent=%p\n", tn, NODE_PARENT(n));
+                               BUG();
+                       }
+               }
+               else
+                       break;
+       }
+
+       /*
+        * n  ----> NULL, LEAF or TNODE
+        *
+        * tp is n's (parent) ----> NULL or TNODE  
+        */
+
+       if(tp && IS_LEAF(tp))
+               BUG();
+
+       t->revision++;
+
+       /* Case 1: n is a leaf. Compare prefixes */
+
+       if (n != NULL && IS_LEAF(n) && tkey_equals(key, n->key)) { 
+               struct leaf *l = ( struct leaf *)  n;
+               
+               li = leaf_info_new(plen);
+               
+               if(! li) 
+                       BUG();
+
+               fa_head = &li->falh;
+               insert_leaf_info(&l->list, li);
+               goto done;
+       }
+       t->size++;
+       l = leaf_new();
+
+       if(! l) 
+               BUG();
+
+       l->key = key;
+       li = leaf_info_new(plen);
+
+       if(! li) 
+               BUG();
+
+       fa_head = &li->falh;
+       insert_leaf_info(&l->list, li);
+
+       /* Case 2: n is NULL, and will just insert a new leaf */
+       if (t->trie && n == NULL) {
+
+               NODE_SET_PARENT(l, tp);
+               
+               if (!tp) 
+                       BUG();
+
+               else {
+                       cindex = tkey_extract_bits(key, tp->pos, tp->bits);
+                       put_child(t, (struct tnode *)tp, cindex, (struct node *)l);
+               }
+       }
+       /* Case 3: n is a LEAF or a TNODE and the key doesn't match. */
+       else {
+               /* 
+                *  Add a new tnode here 
+                *  first tnode need some special handling
+                */
+
+               if (tp)
+                       pos=tp->pos+tp->bits;
+               else
+                       pos=0;
+               if(n) {
+                       newpos = tkey_mismatch(key, pos, n->key);
+                       tn = tnode_new(n->key, newpos, 1);
+               }
+               else {
+                       newpos = 0;
+                       tn = tnode_new(key, newpos, 1); /* First tnode */ 
+               }
+               if(!tn) 
+                       trie_bug("tnode_pfx_new failed");
+
+               NODE_SET_PARENT(tn, tp);
+
+               missbit=tkey_extract_bits(key, newpos, 1);
+               put_child(t, tn, missbit, (struct node *)l);
+               put_child(t, tn, 1-missbit, n);
+
+               if(tp) {
+                       cindex = tkey_extract_bits(key, tp->pos, tp->bits);
+                       put_child(t, (struct tnode *)tp, cindex, (struct node *)tn);
+               }
+               else { 
+                       t->trie = (struct node*) tn; /* First tnode */
+                       tp = tn;
+               }
+       }
+       if(tp && tp->pos+tp->bits > 32) {
+               printk("ERROR tp=%p pos=%d, bits=%d, key=%0x plen=%d\n", 
+                      tp, tp->pos, tp->bits, key, plen);
+       }
+       /* Rebalance the trie */
+       t->trie = trie_rebalance(t, tp);
+done:;
+       return fa_head;
+}
+
+static int
+fn_trie_insert(struct fib_table *tb, struct rtmsg *r, struct kern_rta *rta,
+              struct nlmsghdr *nlhdr, struct netlink_skb_parms *req)
+{
+       struct trie *t = (struct trie *) tb->tb_data;
+       struct fib_alias *fa, *new_fa;
+       struct list_head *fa_head=NULL;
+       struct fib_info *fi;
+       int plen = r->rtm_dst_len;
+       int type = r->rtm_type;
+       u8 tos = r->rtm_tos;
+       u32 key, mask;
+       int err;
+       struct leaf *l;
+
+       if (plen > 32)
+               return -EINVAL;
+
+       key = 0;
+       if (rta->rta_dst) 
+               memcpy(&key, rta->rta_dst, 4);
+
+       key = ntohl(key);
+
+       if(trie_debug)
+               printk("Insert table=%d %08x/%d\n", tb->tb_id, key, plen);
+
+       mask =  ntohl( inet_make_mask(plen) );
+
+       if(key & ~mask)
+               return -EINVAL;
+
+       key = key & mask;
+
+       if  ((fi = fib_create_info(r, rta, nlhdr, &err)) == NULL)
+               goto err;
+
+       l = fib_find_node(t, key);
+       fa = NULL;      
+
+       if(l) {
+               fa_head = get_fa_head(l, plen);
+               fa = fib_find_alias(fa_head, tos, fi->fib_priority);
+       }
+
+       /* 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 head of f.
+        *
+        * If f is NULL, no fib node matched the destination key
+        * and we need to allocate a new one of those as well.
+        */
+
+       if (fa &&
+           fa->fa_info->fib_priority == fi->fib_priority) {
+               struct fib_alias *fa_orig;
+
+               err = -EEXIST;
+               if (nlhdr->nlmsg_flags & NLM_F_EXCL)
+                       goto out;
+
+               if (nlhdr->nlmsg_flags & NLM_F_REPLACE) {
+                       struct fib_info *fi_drop;
+                       u8 state;
+
+                       write_lock_bh(&fib_lock);
+
+                       fi_drop = fa->fa_info;
+                       fa->fa_info = fi;
+                       fa->fa_type = type;
+                       fa->fa_scope = r->rtm_scope;
+                       state = fa->fa_state;
+                       fa->fa_state &= ~FA_S_ACCESSED;
+
+                       write_unlock_bh(&fib_lock);
+
+                       fib_release_info(fi_drop);
+                       if (state & FA_S_ACCESSED)
+                         rt_cache_flush(-1);
+
+                           goto succeeded;
+               }
+               /* Error if we find a perfect match which
+                * uses the same scope, type, and nexthop
+                * information.
+                */
+               fa_orig = fa;
+               list_for_each_entry(fa, fa_orig->fa_list.prev, fa_list) {
+                       if (fa->fa_tos != tos)
+                               break;
+                       if (fa->fa_info->fib_priority != fi->fib_priority)
+                               break;
+                       if (fa->fa_type == type &&
+                           fa->fa_scope == r->rtm_scope &&
+                           fa->fa_info == fi) {
+                               goto out;
+                       }
+               }
+               if (!(nlhdr->nlmsg_flags & NLM_F_APPEND))
+                       fa = fa_orig;
+       }
+       err = -ENOENT;
+       if (!(nlhdr->nlmsg_flags&NLM_F_CREATE))
+               goto out;
+
+       err = -ENOBUFS;
+       new_fa = kmem_cache_alloc(fn_alias_kmem, SLAB_KERNEL);
+       if (new_fa == NULL)
+               goto out;
+
+       new_fa->fa_info = fi;
+       new_fa->fa_tos = tos;
+       new_fa->fa_type = type;
+       new_fa->fa_scope = r->rtm_scope;
+       new_fa->fa_state = 0;
+#if 0
+       new_fa->dst  = NULL;
+#endif
+       /*
+        * Insert new entry to the list.
+        */
+
+       if(!fa_head)
+               fa_head = fib_insert_node(t, key, plen);
+
+       write_lock_bh(&fib_lock);
+
+       list_add_tail(&new_fa->fa_list,
+                (fa ? &fa->fa_list : fa_head));
+
+       write_unlock_bh(&fib_lock);
+
+       rt_cache_flush(-1);
+       rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, tb->tb_id, nlhdr, req);
+succeeded:
+       return 0;
+out:
+       fib_release_info(fi);
+err:;  
+       return err;
+}
+
+static inline int check_leaf(struct trie *t, struct leaf *l,  t_key key, int *plen, const struct flowi *flp, 
+                            struct fib_result *res, int *err)
+{
+       int i;
+       t_key mask;
+       struct leaf_info *li;
+       struct hlist_head *hhead = &l->list;
+       struct hlist_node *node;
+       
+       hlist_for_each_entry(li, node, hhead, hlist) {
+
+               i = li->plen;
+               mask = ntohl(inet_make_mask(i));
+               if (l->key != (key & mask)) 
+                       continue;
+
+               if (((*err) = fib_semantic_match(&li->falh, flp, res, l->key, mask, i)) == 0) {
+                       *plen = i;
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+                       t->stats.semantic_match_passed++;
+#endif
+                       return 1;
+               }
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+               t->stats.semantic_match_miss++;
+#endif
+       }
+       return 0;
+}
+
+static int
+fn_trie_lookup(struct fib_table *tb, const struct flowi *flp, struct fib_result *res)
+{
+       struct trie *t = (struct trie *) tb->tb_data;
+       int plen, ret = 0;
+       struct node *n;
+       struct tnode *pn;
+       int pos, bits;
+       t_key key=ntohl(flp->fl4_dst);
+       int chopped_off;
+       t_key cindex = 0;
+       int current_prefix_length = KEYLENGTH;
+       n = t->trie;
+
+       read_lock(&fib_lock);
+       if(!n)
+               goto failed;
+
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+       t->stats.gets++;
+#endif
+
+       /* Just a leaf? */
+       if (IS_LEAF(n)) {
+               if( check_leaf(t, (struct leaf *)n, key, &plen, flp, res, &ret) )
+                       goto found;
+               goto failed;
+       }
+       pn = (struct tnode *) n;
+       chopped_off = 0;
+       
+        while (pn) {
+
+               pos = pn->pos;
+               bits = pn->bits;
+
+               if(!chopped_off) 
+                       cindex = tkey_extract_bits(MASK_PFX(key, current_prefix_length), pos, bits);
+
+               n = tnode_get_child(pn, cindex);
+
+               if (n == NULL) {
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+                       t->stats.null_node_hit++;
+#endif
+                       goto backtrace;
+               }
+
+               if (IS_TNODE(n)) {
+#define HL_OPTIMIZE
+#ifdef HL_OPTIMIZE
+                       struct tnode *cn = (struct tnode *)n;
+                       t_key node_prefix, key_prefix, pref_mismatch;
+                       int mp;
+
+                       /*
+                        * It's a tnode, and we can do some extra checks here if we 
+                        * like, to avoid descending into a dead-end branch.
+                        * This tnode is in the parent's child array at index 
+                        * key[p_pos..p_pos+p_bits] but potentially with some bits 
+                        * chopped off, so in reality the index may be just a 
+                        * subprefix, padded with zero at the end.
+                        * We can also take a look at any skipped bits in this 
+                        * tnode - everything up to p_pos is supposed to be ok, 
+                        * and the non-chopped bits of the index (se previous
+                        * paragraph) are also guaranteed ok, but the rest is 
+                        * considered unknown.
+                        *
+                        * The skipped bits are key[pos+bits..cn->pos].
+                        */
+                       
+                       /* If current_prefix_length < pos+bits, we are already doing 
+                        * actual prefix  matching, which means everything from 
+                        * pos+(bits-chopped_off) onward must be zero along some 
+                        * branch of this subtree - otherwise there is *no* valid 
+                        * prefix present. Here we can only check the skipped
+                        * bits. Remember, since we have already indexed into the 
+                        * parent's child array, we know that the bits we chopped of 
+                        * *are* zero.
+                        */
+
+                       /* NOTA BENE: CHECKING ONLY SKIPPED BITS FOR THE NEW NODE HERE */
+                       
+                       if (current_prefix_length < pos+bits) {
+                               if (tkey_extract_bits(cn->key, current_prefix_length,
+                                                     cn->pos - current_prefix_length) != 0 ||
+                                   !(cn->child[0]))
+                                       goto backtrace;
+                       }
+
+                       /*
+                        * If chopped_off=0, the index is fully validated and we 
+                        * only need to look at the skipped bits for this, the new, 
+                        * tnode. What we actually want to do is to find out if
+                        * these skipped bits match our key perfectly, or if we will
+                        * have to count on finding a matching prefix further down, 
+                        * because if we do, we would like to have some way of 
+                        * verifying the existence of such a prefix at this point. 
+                        */
+
+                       /* The only thing we can do at this point is to verify that
+                        * any such matching prefix can indeed be a prefix to our
+                        * key, and if the bits in the node we are inspecting that
+                        * do not match our key are not ZERO, this cannot be true.
+                        * Thus, find out where there is a mismatch (before cn->pos)
+                        * and verify that all the mismatching bits are zero in the
+                        * new tnode's key.
+                        */
+
+                       /* Note: We aren't very concerned about the piece of the key 
+                        * that precede pn->pos+pn->bits, since these have already been 
+                        * checked. The bits after cn->pos aren't checked since these are 
+                        * by definition "unknown" at this point. Thus, what we want to 
+                        * see is if we are about to enter the "prefix matching" state, 
+                        * and in that case verify that the skipped bits that will prevail 
+                        * throughout this subtree are zero, as they have to be if we are 
+                        * to find a matching prefix.
+                        */
+
+                       node_prefix = MASK_PFX(cn->key, cn->pos);
+                       key_prefix =  MASK_PFX(key, cn->pos);
+                       pref_mismatch = key_prefix^node_prefix;
+                       mp = 0;
+
+                       /* In short: If skipped bits in this node do not match the search 
+                        * key, enter the "prefix matching" state.directly.
+                        */
+                       if (pref_mismatch) {
+                               while (!(pref_mismatch & (1<<(KEYLENGTH-1)))) {
+                                       mp++;
+                                       pref_mismatch = pref_mismatch <<1;
+                               }
+                               key_prefix = tkey_extract_bits(cn->key, mp, cn->pos-mp);
+                               
+                               if (key_prefix != 0)
+                                       goto backtrace;
+
+                               if (current_prefix_length >= cn->pos)
+                                       current_prefix_length=mp;
+                      }
+#endif
+                      pn = (struct tnode *)n; /* Descend */
+                      chopped_off = 0;
+                      continue;
+               } 
+               if (IS_LEAF(n)) {       
+                       if( check_leaf(t, (struct leaf *)n, key, &plen, flp, res, &ret))
+                               goto found;
+              }
+backtrace:
+               chopped_off++;
+
+               /* As zero don't change the child key (cindex) */
+               while ((chopped_off <= pn->bits) && !(cindex & (1<<(chopped_off-1)))) {
+                       chopped_off++;
+               }
+
+               /* Decrease current_... with bits chopped off */
+               if (current_prefix_length > pn->pos + pn->bits - chopped_off)
+                       current_prefix_length = pn->pos + pn->bits - chopped_off;
+               
+               /*
+                * Either we do the actual chop off according or if we have 
+                * chopped off all bits in this tnode walk up to our parent.
+                */
+
+               if(chopped_off <= pn->bits)
+                       cindex &= ~(1 << (chopped_off-1));
+               else {
+                       if( NODE_PARENT(pn) == NULL)
+                               goto failed;
+                       
+                       /* Get Child's index */
+                       cindex = tkey_extract_bits(pn->key, NODE_PARENT(pn)->pos, NODE_PARENT(pn)->bits);
+                       pn = NODE_PARENT(pn);
+                       chopped_off = 0;
+
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+                       t->stats.backtrack++;
+#endif
+                       goto backtrace;
+               } 
+       }
+failed:
+       ret =  1;
+found:
+       read_unlock(&fib_lock);
+       return ret;
+}
+
+static int trie_leaf_remove(struct trie *t, t_key key)
+{
+       t_key cindex;
+       struct tnode *tp = NULL;
+       struct node *n = t->trie;
+       struct leaf *l;
+
+       if(trie_debug) 
+               printk("entering trie_leaf_remove(%p)\n", n);
+
+       /* Note that in the case skipped bits, those bits are *not* checked!
+        * When we finish this, we will have NULL or a T_LEAF, and the 
+        * T_LEAF may or may not match our key.
+        */
+
+        while (n != NULL && IS_TNODE(n)) {
+               struct tnode *tn = (struct tnode *) n;
+               check_tnode(tn);
+               n = tnode_get_child(tn ,tkey_extract_bits(key, tn->pos, tn->bits));
+
+                       if(n && NODE_PARENT(n) != tn) {
+                               printk("BUG tn=%p, n->parent=%p\n", tn, NODE_PARENT(n));
+                               BUG();
+                       }
+        }
+       l = (struct leaf *) n;
+
+       if(!n || !tkey_equals(l->key, key)) 
+               return 0;
+    
+       /* 
+        * Key found. 
+        * Remove the leaf and rebalance the tree 
+        */
+
+       t->revision++;
+       t->size--;
+
+       tp = NODE_PARENT(n);
+       tnode_free((struct tnode *) n);
+
+       if(tp) {
+               cindex = tkey_extract_bits(key, tp->pos, tp->bits);
+               put_child(t, (struct tnode *)tp, cindex, NULL);
+               t->trie = trie_rebalance(t, tp);
+       }
+       else
+               t->trie = NULL;
+
+       return 1;
+}
+
+static int
+fn_trie_delete(struct fib_table *tb, struct rtmsg *r, struct kern_rta *rta,
+              struct nlmsghdr *nlhdr, struct netlink_skb_parms *req)
+{
+       struct trie *t = (struct trie *) tb->tb_data;
+       u32 key, mask;
+       int plen = r->rtm_dst_len;
+       u8 tos = r->rtm_tos;
+       struct fib_alias *fa, *fa_to_delete;
+       struct list_head *fa_head;
+       struct leaf *l;
+
+       if (plen > 32) 
+               return -EINVAL;
+
+       key = 0;
+       if (rta->rta_dst) 
+               memcpy(&key, rta->rta_dst, 4);
+
+       key = ntohl(key);
+       mask =  ntohl( inet_make_mask(plen) );
+
+       if(key & ~mask)
+               return -EINVAL;
+
+       key = key & mask;
+       l = fib_find_node(t, key);
+
+       if(!l)
+               return -ESRCH;
+
+       fa_head = get_fa_head(l, plen);
+       fa = fib_find_alias(fa_head, tos, 0);
+
+       if (!fa)
+               return -ESRCH;
+
+       if (trie_debug)
+               printk("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
+
+       fa_to_delete = NULL;
+       fa_head = fa->fa_list.prev;
+       list_for_each_entry(fa, fa_head, fa_list) {
+               struct fib_info *fi = fa->fa_info;
+
+               if (fa->fa_tos != tos)
+                       break;
+
+               if ((!r->rtm_type ||
+                    fa->fa_type == r->rtm_type) &&
+                   (r->rtm_scope == RT_SCOPE_NOWHERE ||
+                    fa->fa_scope == r->rtm_scope) &&
+                   (!r->rtm_protocol ||
+                    fi->fib_protocol == r->rtm_protocol) &&
+                   fib_nh_match(r, nlhdr, rta, fi) == 0) {
+                       fa_to_delete = fa;
+                       break;
+               }
+       }
+
+       if (fa_to_delete) {
+               int kill_li = 0;
+               struct leaf_info *li;
+
+               fa = fa_to_delete;
+               rtmsg_fib(RTM_DELROUTE, htonl(key), fa, plen, tb->tb_id, nlhdr, req);
+
+               l = fib_find_node(t, key);
+               li = find_leaf_info(&l->list, plen);
+
+               write_lock_bh(&fib_lock);
+
+               list_del(&fa->fa_list);
+
+               if(list_empty(fa_head)) {
+                       hlist_del(&li->hlist);
+                       kill_li = 1;
+               }
+               write_unlock_bh(&fib_lock);
+               
+               if(kill_li)
+                       free_leaf_info(li);
+
+               if(hlist_empty(&l->list))
+                       trie_leaf_remove(t, key);
+
+               if (fa->fa_state & FA_S_ACCESSED)
+                       rt_cache_flush(-1);
+
+               fn_free_alias(fa);
+               return 0;
+       }
+       return -ESRCH;
+}
+
+static int trie_flush_list(struct trie *t, struct list_head *head)
+{
+       struct fib_alias *fa, *fa_node;
+       int found = 0;
+
+       list_for_each_entry_safe(fa, fa_node, head, fa_list) {
+               struct fib_info *fi = fa->fa_info;
+               
+               if (fi && (fi->fib_flags&RTNH_F_DEAD)) {
+
+                       write_lock_bh(&fib_lock);       
+                       list_del(&fa->fa_list);
+                       write_unlock_bh(&fib_lock); 
+
+                       fn_free_alias(fa);
+                       found++;
+               }
+       }
+       return found;
+}
+
+static int trie_flush_leaf(struct trie *t, struct leaf *l)
+{
+       int found = 0;
+       struct hlist_head *lih = &l->list;
+       struct hlist_node *node, *tmp;
+       struct leaf_info *li = NULL;
+
+       hlist_for_each_entry_safe(li, node, tmp, lih, hlist) {
+                       
+               found += trie_flush_list(t, &li->falh);
+
+               if (list_empty(&li->falh)) {
+
+                       write_lock_bh(&fib_lock); 
+                       hlist_del(&li->hlist);
+                       write_unlock_bh(&fib_lock); 
+
+                       free_leaf_info(li);
+               }
+       }
+       return found;
+}
+
+static struct leaf *nextleaf(struct trie *t, struct leaf *thisleaf)
+{
+       struct node *c = (struct node *) thisleaf;
+       struct tnode *p;
+       int idx;
+
+       if(c == NULL) {
+               if(t->trie == NULL)
+                       return NULL;
+
+               if (IS_LEAF(t->trie))          /* trie w. just a leaf */
+                       return (struct leaf *) t->trie;
+
+               p = (struct tnode*) t->trie;  /* Start */
+       }
+       else 
+               p = (struct tnode *) NODE_PARENT(c);
+       while (p) {
+               int pos, last;
+
+               /*  Find the next child of the parent */
+               if(c)
+                       pos  = 1 + tkey_extract_bits(c->key, p->pos, p->bits);
+               else 
+                       pos = 0;
+
+               last = 1 << p->bits;
+               for(idx = pos; idx < last ; idx++) {
+                       if( p->child[idx]) {
+
+                               /* Decend if tnode */
+
+                               while (IS_TNODE(p->child[idx])) {
+                                       p = (struct tnode*) p->child[idx];
+                                       idx = 0;
+                                       
+                                       /* Rightmost non-NULL branch */
+                                       if( p && IS_TNODE(p) )
+                                               while ( p->child[idx] == NULL && idx < (1 << p->bits) ) idx++;
+
+                                       /* Done with this tnode? */
+                                       if( idx >= (1 << p->bits) || p->child[idx] == NULL ) 
+                                               goto up;
+                               }
+                               return (struct leaf*) p->child[idx];
+                       }
+               }
+up:
+               /* No more children go up one step  */
+               c = (struct node*) p;
+               p = (struct tnode *) NODE_PARENT(p);
+       }
+       return NULL; /* Ready. Root of trie */
+}
+
+static int fn_trie_flush(struct fib_table *tb)
+{
+       struct trie *t = (struct trie *) tb->tb_data;
+       struct leaf *ll = NULL, *l = NULL;
+       int found = 0, h;
+
+       t->revision++;
+
+       for (h=0; (l = nextleaf(t, l)) != NULL; h++) {
+               found += trie_flush_leaf(t, l);
+
+               if (ll && hlist_empty(&ll->list))
+                       trie_leaf_remove(t, ll->key);
+               ll = l;
+       }
+
+       if (ll && hlist_empty(&ll->list))
+               trie_leaf_remove(t, ll->key);
+
+       if(trie_debug) 
+               printk("trie_flush found=%d\n", found);
+       return found;
+}
+
+static int trie_last_dflt=-1;
+
+static void
+fn_trie_select_default(struct fib_table *tb, const struct flowi *flp, struct fib_result *res)
+{
+       struct trie *t = (struct trie *) tb->tb_data;
+       int order, last_idx;
+       struct fib_info *fi = NULL;
+       struct fib_info *last_resort;
+       struct fib_alias *fa = NULL;
+       struct list_head *fa_head;
+       struct leaf *l;
+
+       last_idx = -1;
+       last_resort = NULL;
+       order = -1;
+
+       read_lock(&fib_lock);
+       
+       l = fib_find_node(t, 0);
+       if(!l) 
+               goto out;
+
+       fa_head = get_fa_head(l, 0);
+       if(!fa_head)
+               goto out;
+
+       if (list_empty(fa_head)) 
+               goto out;
+
+       list_for_each_entry(fa, fa_head, fa_list) {
+               struct fib_info *next_fi = fa->fa_info;
+               
+               if (fa->fa_scope != res->scope ||
+                   fa->fa_type != RTN_UNICAST)
+                       continue;
+               
+               if (next_fi->fib_priority > res->fi->fib_priority)
+                       break;
+               if (!next_fi->fib_nh[0].nh_gw ||
+                   next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
+                       continue;
+               fa->fa_state |= FA_S_ACCESSED;
+               
+               if (fi == NULL) {
+                       if (next_fi != res->fi)
+                               break;
+               } else if (!fib_detect_death(fi, order, &last_resort,
+                                            &last_idx, &trie_last_dflt)) {
+                       if (res->fi)
+                               fib_info_put(res->fi);
+                       res->fi = fi;
+                       atomic_inc(&fi->fib_clntref);
+                       trie_last_dflt = order;
+                       goto out;
+               }
+               fi = next_fi;
+               order++;
+       }
+       if (order <= 0 || fi == NULL) {
+               trie_last_dflt = -1;
+               goto out;
+       }
+
+       if (!fib_detect_death(fi, order, &last_resort, &last_idx, &trie_last_dflt)) {
+               if (res->fi)
+                       fib_info_put(res->fi);
+               res->fi = fi;
+               atomic_inc(&fi->fib_clntref);
+               trie_last_dflt = order;
+               goto out;
+       }
+       if (last_idx >= 0) {
+               if (res->fi)
+                       fib_info_put(res->fi);
+               res->fi = last_resort;
+               if (last_resort)
+                       atomic_inc(&last_resort->fib_clntref);
+       }
+       trie_last_dflt = last_idx;
+ out:;
+       read_unlock(&fib_lock); 
+}
+
+static int fn_trie_dump_fa(t_key key, int plen, struct list_head *fah, struct fib_table *tb, 
+                          struct sk_buff *skb, struct netlink_callback *cb)
+{
+       int i, s_i;
+       struct fib_alias *fa;
+
+       u32 xkey=htonl(key);
+
+       s_i=cb->args[3];
+       i = 0;
+
+       list_for_each_entry(fa, fah, fa_list) {
+               if (i < s_i) {
+                       i++;
+                       continue;
+               }
+               if (fa->fa_info->fib_nh == NULL) {
+                       printk("Trie error _fib_nh=NULL in fa[%d] k=%08x plen=%d\n", i, key, plen);
+                       i++;
+                       continue;
+               }
+               if (fa->fa_info == NULL) {
+                       printk("Trie error fa_info=NULL in fa[%d] k=%08x plen=%d\n", i, key, plen);
+                       i++;
+                       continue;
+               }
+
+               if (fib_dump_info(skb, NETLINK_CB(cb->skb).pid,
+                                 cb->nlh->nlmsg_seq,
+                                 RTM_NEWROUTE,
+                                 tb->tb_id,
+                                 fa->fa_type,
+                                 fa->fa_scope,
+                                 &xkey,
+                                 plen,
+                                 fa->fa_tos,
+                                 fa->fa_info) < 0) {
+                       cb->args[3] = i;
+                       return -1;
+                       }
+               i++;
+       }
+       cb->args[3]=i;
+       return skb->len;
+}
+
+static int fn_trie_dump_plen(struct trie *t, int plen, struct fib_table *tb, struct sk_buff *skb, 
+                            struct netlink_callback *cb)
+{
+       int h, s_h;
+       struct list_head *fa_head;
+       struct leaf *l = NULL;
+       s_h=cb->args[2];
+
+       for (h=0; (l = nextleaf(t, l)) != NULL; h++) {
+
+               if (h < s_h)
+                       continue;
+               if (h > s_h)
+                       memset(&cb->args[3], 0,
+                              sizeof(cb->args) - 3*sizeof(cb->args[0]));
+
+               fa_head = get_fa_head(l, plen);
+               
+               if(!fa_head)
+                       continue;
+
+               if(list_empty(fa_head))
+                       continue;
+
+               if (fn_trie_dump_fa(l->key, plen, fa_head, tb, skb, cb)<0) {
+                       cb->args[2]=h;
+                       return -1;
+               }
+       }
+       cb->args[2]=h;
+       return skb->len;
+}
+
+static int fn_trie_dump(struct fib_table *tb, struct sk_buff *skb, struct netlink_callback *cb)
+{
+       int m, s_m;
+       struct trie *t = (struct trie *) tb->tb_data;
+
+       s_m = cb->args[1];
+
+       read_lock(&fib_lock);
+       for (m=0; m<=32; m++) {
+
+               if (m < s_m)
+                       continue;
+               if (m > s_m)
+                       memset(&cb->args[2], 0,
+                              sizeof(cb->args) - 2*sizeof(cb->args[0]));
+
+               if (fn_trie_dump_plen(t, 32-m, tb, skb, cb)<0) {
+                       cb->args[1] = m;
+                       goto out;
+               }
+       }
+       read_unlock(&fib_lock);
+       cb->args[1] = m;
+       return skb->len;
+ out:
+       read_unlock(&fib_lock);
+       return -1;
+}
+
+/* Fix more generic FIB names for init later */
+
+#ifdef CONFIG_IP_MULTIPLE_TABLES
+struct fib_table * fib_hash_init(int id)
+#else
+struct fib_table * __init fib_hash_init(int id)
+#endif
+{
+       struct fib_table *tb;
+       struct trie *t;
+
+       if (fn_alias_kmem == NULL)
+               fn_alias_kmem = kmem_cache_create("ip_fib_alias",
+                                                 sizeof(struct fib_alias),
+                                                 0, SLAB_HWCACHE_ALIGN,
+                                                 NULL, NULL);
+
+       tb = kmalloc(sizeof(struct fib_table) + sizeof(struct trie),
+                    GFP_KERNEL);
+       if (tb == NULL)
+               return NULL;
+
+       tb->tb_id = id;
+       tb->tb_lookup = fn_trie_lookup;
+       tb->tb_insert = fn_trie_insert;
+       tb->tb_delete = fn_trie_delete;
+       tb->tb_flush = fn_trie_flush;
+       tb->tb_select_default = fn_trie_select_default;
+       tb->tb_dump = fn_trie_dump;
+       memset(tb->tb_data, 0, sizeof(struct trie));
+
+       t = (struct trie *) tb->tb_data;
+
+       trie_init(t);
+
+       if (id == RT_TABLE_LOCAL) 
+                trie_local=t;
+         else if (id == RT_TABLE_MAIN) 
+                trie_main=t;
+
+       if (id == RT_TABLE_LOCAL)
+               printk("IPv4 FIB: Using LC-trie version %s\n", VERSION);
+
+       return tb;
+}
+
+/* Trie dump functions */
+
+static void putspace_seq(struct seq_file *seq, int n)
+{
+       while (n--) seq_printf(seq, " ");
+}
+
+static void printbin_seq(struct seq_file *seq, unsigned int v, int bits)
+{
+       while (bits--)
+               seq_printf(seq, "%s", (v & (1<<bits))?"1":"0");
+}
+
+static void printnode_seq(struct seq_file *seq, int indent, struct node *n, 
+                  int pend, int cindex, int bits)
+{
+       putspace_seq(seq, indent);
+       if (IS_LEAF(n))
+               seq_printf(seq, "|");
+       else
+               seq_printf(seq, "+");
+       if (bits) {
+               seq_printf(seq, "%d/", cindex);
+               printbin_seq(seq, cindex, bits);
+               seq_printf(seq, ": ");
+       }
+       else
+               seq_printf(seq, "<root>: ");
+       seq_printf(seq, "%s:%p ", IS_LEAF(n)?"Leaf":"Internal node", n);
+
+       if (IS_LEAF(n))
+               seq_printf(seq, "key=%d.%d.%d.%d\n", 
+                          n->key >> 24, (n->key >> 16) % 256, (n->key >> 8) % 256, n->key % 256);
+       else {
+               int plen=((struct tnode *)n)->pos;
+               t_key prf=MASK_PFX(n->key, plen);
+               seq_printf(seq, "key=%d.%d.%d.%d/%d\n", 
+                          prf >> 24, (prf >> 16) % 256, (prf >> 8) % 256, prf % 256, plen);
+       }
+       if (IS_LEAF(n)) {
+               struct leaf *l=(struct leaf *)n;
+               struct fib_alias *fa;
+               int i;
+               for (i=32; i>=0; i--)
+                 if(find_leaf_info(&l->list, i)) {
+                       
+                               struct list_head *fa_head = get_fa_head(l, i);
+                               
+                               if(!fa_head)
+                                       continue;
+
+                               if(list_empty(fa_head))
+                                       continue;
+
+                               putspace_seq(seq, indent+2);
+                               seq_printf(seq, "{/%d...dumping}\n", i);
+
+
+                               list_for_each_entry(fa, fa_head, fa_list) {
+                                       putspace_seq(seq, indent+2);
+                                       if (fa->fa_info->fib_nh == NULL) {
+                                               seq_printf(seq, "Error _fib_nh=NULL\n");
+                                               continue;
+                                       }
+                                       if (fa->fa_info == NULL) {
+                                               seq_printf(seq, "Error fa_info=NULL\n");
+                                               continue;
+                                       }
+
+                                       seq_printf(seq, "{type=%d scope=%d TOS=%d}\n",
+                                             fa->fa_type,
+                                             fa->fa_scope,
+                                             fa->fa_tos);
+                               }
+                       }
+       }
+       else if (IS_TNODE(n)) {
+               struct tnode *tn=(struct tnode *)n;
+               putspace_seq(seq, indent); seq_printf(seq, "|    ");
+               seq_printf(seq, "{key prefix=%08x/", tn->key&TKEY_GET_MASK(0, tn->pos));
+               printbin_seq(seq, tkey_extract_bits(tn->key, 0, tn->pos), tn->pos);
+               seq_printf(seq, "}\n");
+               putspace_seq(seq, indent); seq_printf(seq, "|    ");
+               seq_printf(seq, "{pos=%d", tn->pos);
+               seq_printf(seq, " (skip=%d bits)", tn->pos - pend);
+               seq_printf(seq, " bits=%d (%u children)}\n", tn->bits, (1 << tn->bits));
+               putspace_seq(seq, indent); seq_printf(seq, "|    ");
+               seq_printf(seq, "{empty=%d full=%d}\n", tn->empty_children, tn->full_children);
+       }
+}
+
+static void trie_dump_seq(struct seq_file *seq, struct trie *t)
+{
+       struct node *n=t->trie;
+       int cindex=0;
+       int indent=1;
+       int pend=0;
+       int depth = 0;
+
+       read_lock(&fib_lock);
+
+       seq_printf(seq, "------ trie_dump of t=%p ------\n", t);
+       if (n) {
+               printnode_seq(seq, indent, n, pend, cindex, 0);
+               if (IS_TNODE(n)) {
+                       struct tnode *tn=(struct tnode *)n;
+                       pend = tn->pos+tn->bits;
+                       putspace_seq(seq, indent); seq_printf(seq, "\\--\n");
+                       indent += 3;
+                       depth++;
+
+                       while (tn && cindex < (1 << tn->bits)) {
+                               if (tn->child[cindex]) {
+                                       
+                                       /* Got a child */
+                                       
+                                       printnode_seq(seq, indent, tn->child[cindex], pend, cindex, tn->bits);
+                                       if (IS_LEAF(tn->child[cindex])) { 
+                                               cindex++;
+                                               
+                                       }
+                                       else {
+                                               /* 
+                                                * New tnode. Decend one level 
+                                                */
+                                               
+                                               depth++;
+                                               n=tn->child[cindex];
+                                               tn=(struct tnode *)n;
+                                               pend=tn->pos+tn->bits;
+                                               putspace_seq(seq, indent); seq_printf(seq, "\\--\n");
+                                               indent+=3;
+                                               cindex=0;
+                                       }
+                               }
+                               else 
+                                       cindex++;
+
+                               /*
+                                * Test if we are done 
+                                */
+                               
+                               while (cindex >= (1 << tn->bits)) {
+
+                                       /*
+                                        * Move upwards and test for root
+                                        * pop off all traversed  nodes
+                                        */
+                                       
+                                       if (NODE_PARENT(tn) == NULL) {
+                                               tn = NULL;
+                                               n = NULL;
+                                               break;
+                                       }
+                                       else {
+                                               cindex = tkey_extract_bits(tn->key, NODE_PARENT(tn)->pos, NODE_PARENT(tn)->bits);
+                                               tn = NODE_PARENT(tn);
+                                               cindex++;
+                                               n=(struct node *)tn;
+                                               pend=tn->pos+tn->bits;
+                                               indent-=3;
+                                               depth--;
+                                       }
+                               }
+                       }
+               }
+               else n = NULL;
+       }
+       else seq_printf(seq, "------ trie is empty\n");
+
+       read_unlock(&fib_lock);
+}
+
+static struct trie_stat *trie_stat_new(void)
+{
+       struct trie_stat *s = kmalloc(sizeof(struct trie_stat), GFP_KERNEL);
+       int i;
+       
+       if(s) {
+               s->totdepth = 0;
+               s->maxdepth = 0;
+               s->tnodes = 0;
+               s->leaves = 0;
+               s->nullpointers = 0;
+               
+               for(i=0; i< MAX_CHILDS; i++)
+                       s->nodesizes[i] = 0;
+       }
+       return s;
+}    
+
+static struct trie_stat *trie_collect_stats(struct trie *t)
+{
+       struct node *n=t->trie;
+       struct trie_stat *s = trie_stat_new();
+       int cindex = 0;
+       int indent = 1;
+       int pend = 0;
+       int depth = 0;
+
+       read_lock(&fib_lock);           
+
+       if (s) {
+               if (n) {
+                       if (IS_TNODE(n)) {
+                               struct tnode *tn = (struct tnode *)n;
+                               pend=tn->pos+tn->bits;
+                               indent += 3;
+                               s->nodesizes[tn->bits]++;
+                               depth++;
+
+                               while (tn && cindex < (1 << tn->bits)) {
+                                       if (tn->child[cindex]) {
+                                               /* Got a child */
+                                       
+                                               if (IS_LEAF(tn->child[cindex])) { 
+                                                       cindex++;
+                                               
+                                                       /* stats */
+                                                       if (depth > s->maxdepth)
+                                                               s->maxdepth = depth;
+                                                       s->totdepth += depth;
+                                                       s->leaves++;
+                                               }
+                                       
+                                               else {
+                                                       /* 
+                                                        * New tnode. Decend one level 
+                                                        */
+                                               
+                                                       s->tnodes++;
+                                                       s->nodesizes[tn->bits]++;
+                                                       depth++;
+                                               
+                                                       n = tn->child[cindex];
+                                                       tn = (struct tnode *)n;
+                                                       pend = tn->pos+tn->bits;
+
+                                                       indent += 3;
+                                                       cindex = 0;
+                                               }
+                                       }
+                                       else {
+                                               cindex++;
+                                               s->nullpointers++; 
+                                       }
+
+                                       /*
+                                        * Test if we are done 
+                                        */
+                               
+                                       while (cindex >= (1 << tn->bits)) {
+
+                                               /*
+                                                * Move upwards and test for root
+                                                * pop off all traversed  nodes
+                                                */
+
+                                               
+                                               if (NODE_PARENT(tn) == NULL) {
+                                                       tn = NULL;
+                                                       n = NULL;
+                                                       break;
+                                               }
+                                               else {
+                                                       cindex = tkey_extract_bits(tn->key, NODE_PARENT(tn)->pos, NODE_PARENT(tn)->bits);
+                                                       tn = NODE_PARENT(tn);
+                                                       cindex++; 
+                                                       n = (struct node *)tn;
+                                                       pend=tn->pos+tn->bits;
+                                                       indent -= 3;
+                                                       depth--;
+                                               }
+                                       }
+                               }
+                       }
+                       else n = NULL;
+               }
+       }
+
+       read_unlock(&fib_lock);         
+       return s;
+}
+
+#ifdef CONFIG_PROC_FS
+
+static struct fib_alias *fib_triestat_get_first(struct seq_file *seq)
+{
+       return NULL;
+}
+
+static struct fib_alias *fib_triestat_get_next(struct seq_file *seq)
+{
+       return NULL;
+}
+
+static void *fib_triestat_seq_start(struct seq_file *seq, loff_t *pos)
+{
+       void *v = NULL;
+
+       if (ip_fib_main_table)
+               v = *pos ? fib_triestat_get_next(seq) : SEQ_START_TOKEN;
+       return v;
+}
+
+static void *fib_triestat_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+       ++*pos;
+       return v == SEQ_START_TOKEN ? fib_triestat_get_first(seq) : fib_triestat_get_next(seq);
+}
+
+static void fib_triestat_seq_stop(struct seq_file *seq, void *v)
+{
+
+}
+
+/* 
+ *     This outputs /proc/net/fib_triestats
+ *
+ *     It always works in backward compatibility mode.
+ *     The format of the file is not supposed to be changed.
+ */
+
+static void collect_and_show(struct trie *t, struct seq_file *seq)
+{
+       int bytes = 0; /* How many bytes are used, a ref is 4 bytes */
+       int i, max, pointers;
+        struct trie_stat *stat;
+       int avdepth;
+
+       stat = trie_collect_stats(t);
+
+       bytes=0;
+       seq_printf(seq, "trie=%p\n", t);
+
+       if (stat) {
+               if (stat->leaves)
+                       avdepth=stat->totdepth*100 / stat->leaves;
+               else
+                       avdepth=0;
+               seq_printf(seq, "Aver depth: %d.%02d\n", avdepth / 100, avdepth % 100 );
+               seq_printf(seq, "Max depth: %4d\n", stat->maxdepth);
+                               
+               seq_printf(seq, "Leaves: %d\n", stat->leaves);
+               bytes += sizeof(struct leaf) * stat->leaves;
+               seq_printf(seq, "Internal nodes: %d\n", stat->tnodes);
+               bytes += sizeof(struct tnode) * stat->tnodes;
+
+               max = MAX_CHILDS-1;
+
+               while (max >= 0 && stat->nodesizes[max] == 0)
+                       max--;
+               pointers = 0;
+
+               for (i = 1; i <= max; i++) 
+                       if (stat->nodesizes[i] != 0) {
+                               seq_printf(seq, "  %d: %d",  i, stat->nodesizes[i]);
+                               pointers += (1<<i) * stat->nodesizes[i];
+                       }
+               seq_printf(seq, "\n");
+               seq_printf(seq, "Pointers: %d\n", pointers);
+               bytes += sizeof(struct node *) * pointers;
+               seq_printf(seq, "Null ptrs: %d\n", stat->nullpointers);
+               seq_printf(seq, "Total size: %d  kB\n", bytes / 1024);
+
+               kfree(stat);
+       }
+
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+       seq_printf(seq, "Counters:\n---------\n");
+       seq_printf(seq,"gets = %d\n", t->stats.gets);
+       seq_printf(seq,"backtracks = %d\n", t->stats.backtrack);
+       seq_printf(seq,"semantic match passed = %d\n", t->stats.semantic_match_passed);
+       seq_printf(seq,"semantic match miss = %d\n", t->stats.semantic_match_miss);
+       seq_printf(seq,"null node hit= %d\n", t->stats.null_node_hit);
+#ifdef CLEAR_STATS
+       memset(&(t->stats), 0, sizeof(t->stats));
+#endif
+#endif /*  CONFIG_IP_FIB_TRIE_STATS */
+}
+
+static int fib_triestat_seq_show(struct seq_file *seq, void *v)
+{
+       char bf[128];
+    
+       if (v == SEQ_START_TOKEN) {
+               seq_printf(seq, "Basic info: size of leaf: %Zd bytes, size of tnode: %Zd bytes.\n", 
+                          sizeof(struct leaf), sizeof(struct tnode));
+               if (trie_local) 
+                       collect_and_show(trie_local, seq);
+
+               if (trie_main) 
+                       collect_and_show(trie_main, seq);
+       }
+       else {
+               snprintf(bf, sizeof(bf),
+                        "*\t%08X\t%08X", 200, 400);
+               
+               seq_printf(seq, "%-127s\n", bf);
+       }
+       return 0;
+}
+
+static struct seq_operations fib_triestat_seq_ops = {
+       .start  = fib_triestat_seq_start,
+       .next   = fib_triestat_seq_next,
+       .stop   = fib_triestat_seq_stop,
+       .show   = fib_triestat_seq_show,
+};
+
+static int fib_triestat_seq_open(struct inode *inode, struct file *file)
+{
+       struct seq_file *seq;
+       int rc = -ENOMEM;
+
+       rc = seq_open(file, &fib_triestat_seq_ops);
+       if (rc)
+               goto out_kfree;
+
+       seq          = file->private_data;
+out:
+       return rc;
+out_kfree:
+       goto out;
+}
+
+static struct file_operations fib_triestat_seq_fops = {
+       .owner          = THIS_MODULE,
+       .open           = fib_triestat_seq_open,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = seq_release_private,
+};
+
+int __init fib_stat_proc_init(void)
+{
+       if (!proc_net_fops_create("fib_triestat", S_IRUGO, &fib_triestat_seq_fops))
+               return -ENOMEM;
+       return 0;
+}
+
+void __init fib_stat_proc_exit(void)
+{
+       proc_net_remove("fib_triestat");
+}
+
+static struct fib_alias *fib_trie_get_first(struct seq_file *seq)
+{
+       return NULL;
+}
+
+static struct fib_alias *fib_trie_get_next(struct seq_file *seq)
+{
+       return NULL;
+}
+
+static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
+{
+       void *v = NULL;
+
+       if (ip_fib_main_table)
+               v = *pos ? fib_trie_get_next(seq) : SEQ_START_TOKEN;
+       return v;
+}
+
+static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+       ++*pos;
+       return v == SEQ_START_TOKEN ? fib_trie_get_first(seq) : fib_trie_get_next(seq);
+}
+
+static void fib_trie_seq_stop(struct seq_file *seq, void *v)
+{
+
+}
+
+/* 
+ *     This outputs /proc/net/fib_trie.
+ *
+ *     It always works in backward compatibility mode.
+ *     The format of the file is not supposed to be changed.
+ */
+
+static int fib_trie_seq_show(struct seq_file *seq, void *v)
+{
+       char bf[128];
+
+       if (v == SEQ_START_TOKEN) {
+               if (trie_local) 
+                       trie_dump_seq(seq, trie_local);
+
+               if (trie_main) 
+                       trie_dump_seq(seq, trie_main);
+       }
+
+       else {
+               snprintf(bf, sizeof(bf),
+                        "*\t%08X\t%08X", 200, 400);
+               seq_printf(seq, "%-127s\n", bf);
+       }
+
+       return 0;
+}
+
+static 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,
+};
+
+static int fib_trie_seq_open(struct inode *inode, struct file *file)
+{
+       struct seq_file *seq;
+       int rc = -ENOMEM;
+
+       rc = seq_open(file, &fib_trie_seq_ops);
+       if (rc)
+               goto out_kfree;
+
+       seq          = file->private_data;
+out:
+       return rc;
+out_kfree:
+       goto out;
+}
+
+static struct file_operations fib_trie_seq_fops = {
+       .owner          = THIS_MODULE,
+       .open           = fib_trie_seq_open,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = seq_release_private,
+};
+
+int __init fib_proc_init(void)
+{
+       if (!proc_net_fops_create("fib_trie", S_IRUGO, &fib_trie_seq_fops))
+               return -ENOMEM;
+       return 0;
+}
+
+void __init fib_proc_exit(void)
+{
+       proc_net_remove("fib_trie");
+}
+
+#endif /* CONFIG_PROC_FS */