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Linux/net/ipv4/fib_trie.c

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  1 /*
  2  *   This program is free software; you can redistribute it and/or
  3  *   modify it under the terms of the GNU General Public License
  4  *   as published by the Free Software Foundation; either version
  5  *   2 of the License, or (at your option) any later version.
  6  *
  7  *   Robert Olsson <robert.olsson@its.uu.se> Uppsala Universitet
  8  *     & Swedish University of Agricultural Sciences.
  9  *
 10  *   Jens Laas <jens.laas@data.slu.se> Swedish University of
 11  *     Agricultural Sciences.
 12  *
 13  *   Hans Liss <hans.liss@its.uu.se>  Uppsala Universitet
 14  *
 15  * This work is based on the LPC-trie which is originally described in:
 16  *
 17  * An experimental study of compression methods for dynamic tries
 18  * Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
 19  * http://www.csc.kth.se/~snilsson/software/dyntrie2/
 20  *
 21  *
 22  * IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
 23  * IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
 24  *
 25  *
 26  * Code from fib_hash has been reused which includes the following header:
 27  *
 28  *
 29  * INET         An implementation of the TCP/IP protocol suite for the LINUX
 30  *              operating system.  INET is implemented using the  BSD Socket
 31  *              interface as the means of communication with the user level.
 32  *
 33  *              IPv4 FIB: lookup engine and maintenance routines.
 34  *
 35  *
 36  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 37  *
 38  *              This program is free software; you can redistribute it and/or
 39  *              modify it under the terms of the GNU General Public License
 40  *              as published by the Free Software Foundation; either version
 41  *              2 of the License, or (at your option) any later version.
 42  *
 43  * Substantial contributions to this work comes from:
 44  *
 45  *              David S. Miller, <davem@davemloft.net>
 46  *              Stephen Hemminger <shemminger@osdl.org>
 47  *              Paul E. McKenney <paulmck@us.ibm.com>
 48  *              Patrick McHardy <kaber@trash.net>
 49  */
 50 
 51 #define VERSION "0.409"
 52 
 53 #include <linux/uaccess.h>
 54 #include <linux/bitops.h>
 55 #include <linux/types.h>
 56 #include <linux/kernel.h>
 57 #include <linux/mm.h>
 58 #include <linux/string.h>
 59 #include <linux/socket.h>
 60 #include <linux/sockios.h>
 61 #include <linux/errno.h>
 62 #include <linux/in.h>
 63 #include <linux/inet.h>
 64 #include <linux/inetdevice.h>
 65 #include <linux/netdevice.h>
 66 #include <linux/if_arp.h>
 67 #include <linux/proc_fs.h>
 68 #include <linux/rcupdate.h>
 69 #include <linux/skbuff.h>
 70 #include <linux/netlink.h>
 71 #include <linux/init.h>
 72 #include <linux/list.h>
 73 #include <linux/slab.h>
 74 #include <linux/export.h>
 75 #include <linux/vmalloc.h>
 76 #include <linux/notifier.h>
 77 #include <net/net_namespace.h>
 78 #include <net/ip.h>
 79 #include <net/protocol.h>
 80 #include <net/route.h>
 81 #include <net/tcp.h>
 82 #include <net/sock.h>
 83 #include <net/ip_fib.h>
 84 #include <net/fib_notifier.h>
 85 #include <trace/events/fib.h>
 86 #include "fib_lookup.h"
 87 
 88 static int call_fib_entry_notifier(struct notifier_block *nb, struct net *net,
 89                                    enum fib_event_type event_type, u32 dst,
 90                                    int dst_len, struct fib_alias *fa)
 91 {
 92         struct fib_entry_notifier_info info = {
 93                 .dst = dst,
 94                 .dst_len = dst_len,
 95                 .fi = fa->fa_info,
 96                 .tos = fa->fa_tos,
 97                 .type = fa->fa_type,
 98                 .tb_id = fa->tb_id,
 99         };
100         return call_fib4_notifier(nb, net, event_type, &info.info);
101 }
102 
103 static int call_fib_entry_notifiers(struct net *net,
104                                     enum fib_event_type event_type, u32 dst,
105                                     int dst_len, struct fib_alias *fa,
106                                     struct netlink_ext_ack *extack)
107 {
108         struct fib_entry_notifier_info info = {
109                 .info.extack = extack,
110                 .dst = dst,
111                 .dst_len = dst_len,
112                 .fi = fa->fa_info,
113                 .tos = fa->fa_tos,
114                 .type = fa->fa_type,
115                 .tb_id = fa->tb_id,
116         };
117         return call_fib4_notifiers(net, event_type, &info.info);
118 }
119 
120 #define MAX_STAT_DEPTH 32
121 
122 #define KEYLENGTH       (8*sizeof(t_key))
123 #define KEY_MAX         ((t_key)~0)
124 
125 typedef unsigned int t_key;
126 
127 #define IS_TRIE(n)      ((n)->pos >= KEYLENGTH)
128 #define IS_TNODE(n)     ((n)->bits)
129 #define IS_LEAF(n)      (!(n)->bits)
130 
131 struct key_vector {
132         t_key key;
133         unsigned char pos;              /* 2log(KEYLENGTH) bits needed */
134         unsigned char bits;             /* 2log(KEYLENGTH) bits needed */
135         unsigned char slen;
136         union {
137                 /* This list pointer if valid if (pos | bits) == 0 (LEAF) */
138                 struct hlist_head leaf;
139                 /* This array is valid if (pos | bits) > 0 (TNODE) */
140                 struct key_vector __rcu *tnode[0];
141         };
142 };
143 
144 struct tnode {
145         struct rcu_head rcu;
146         t_key empty_children;           /* KEYLENGTH bits needed */
147         t_key full_children;            /* KEYLENGTH bits needed */
148         struct key_vector __rcu *parent;
149         struct key_vector kv[1];
150 #define tn_bits kv[0].bits
151 };
152 
153 #define TNODE_SIZE(n)   offsetof(struct tnode, kv[0].tnode[n])
154 #define LEAF_SIZE       TNODE_SIZE(1)
155 
156 #ifdef CONFIG_IP_FIB_TRIE_STATS
157 struct trie_use_stats {
158         unsigned int gets;
159         unsigned int backtrack;
160         unsigned int semantic_match_passed;
161         unsigned int semantic_match_miss;
162         unsigned int null_node_hit;
163         unsigned int resize_node_skipped;
164 };
165 #endif
166 
167 struct trie_stat {
168         unsigned int totdepth;
169         unsigned int maxdepth;
170         unsigned int tnodes;
171         unsigned int leaves;
172         unsigned int nullpointers;
173         unsigned int prefixes;
174         unsigned int nodesizes[MAX_STAT_DEPTH];
175 };
176 
177 struct trie {
178         struct key_vector kv[1];
179 #ifdef CONFIG_IP_FIB_TRIE_STATS
180         struct trie_use_stats __percpu *stats;
181 #endif
182 };
183 
184 static struct key_vector *resize(struct trie *t, struct key_vector *tn);
185 static size_t tnode_free_size;
186 
187 /*
188  * synchronize_rcu after call_rcu for that many pages; it should be especially
189  * useful before resizing the root node with PREEMPT_NONE configs; the value was
190  * obtained experimentally, aiming to avoid visible slowdown.
191  */
192 static const int sync_pages = 128;
193 
194 static struct kmem_cache *fn_alias_kmem __read_mostly;
195 static struct kmem_cache *trie_leaf_kmem __read_mostly;
196 
197 static inline struct tnode *tn_info(struct key_vector *kv)
198 {
199         return container_of(kv, struct tnode, kv[0]);
200 }
201 
202 /* caller must hold RTNL */
203 #define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
204 #define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
205 
206 /* caller must hold RCU read lock or RTNL */
207 #define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
208 #define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
209 
210 /* wrapper for rcu_assign_pointer */
211 static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
212 {
213         if (n)
214                 rcu_assign_pointer(tn_info(n)->parent, tp);
215 }
216 
217 #define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(n)->parent, p)
218 
219 /* This provides us with the number of children in this node, in the case of a
220  * leaf this will return 0 meaning none of the children are accessible.
221  */
222 static inline unsigned long child_length(const struct key_vector *tn)
223 {
224         return (1ul << tn->bits) & ~(1ul);
225 }
226 
227 #define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
228 
229 static inline unsigned long get_index(t_key key, struct key_vector *kv)
230 {
231         unsigned long index = key ^ kv->key;
232 
233         if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
234                 return 0;
235 
236         return index >> kv->pos;
237 }
238 
239 /* To understand this stuff, an understanding of keys and all their bits is
240  * necessary. Every node in the trie has a key associated with it, but not
241  * all of the bits in that key are significant.
242  *
243  * Consider a node 'n' and its parent 'tp'.
244  *
245  * If n is a leaf, every bit in its key is significant. Its presence is
246  * necessitated by path compression, since during a tree traversal (when
247  * searching for a leaf - unless we are doing an insertion) we will completely
248  * ignore all skipped bits we encounter. Thus we need to verify, at the end of
249  * a potentially successful search, that we have indeed been walking the
250  * correct key path.
251  *
252  * Note that we can never "miss" the correct key in the tree if present by
253  * following the wrong path. Path compression ensures that segments of the key
254  * that are the same for all keys with a given prefix are skipped, but the
255  * skipped part *is* identical for each node in the subtrie below the skipped
256  * bit! trie_insert() in this implementation takes care of that.
257  *
258  * if n is an internal node - a 'tnode' here, the various parts of its key
259  * have many different meanings.
260  *
261  * Example:
262  * _________________________________________________________________
263  * | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
264  * -----------------------------------------------------------------
265  *  31  30  29  28  27  26  25  24  23  22  21  20  19  18  17  16
266  *
267  * _________________________________________________________________
268  * | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
269  * -----------------------------------------------------------------
270  *  15  14  13  12  11  10   9   8   7   6   5   4   3   2   1   0
271  *
272  * tp->pos = 22
273  * tp->bits = 3
274  * n->pos = 13
275  * n->bits = 4
276  *
277  * First, let's just ignore the bits that come before the parent tp, that is
278  * the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
279  * point we do not use them for anything.
280  *
281  * The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
282  * index into the parent's child array. That is, they will be used to find
283  * 'n' among tp's children.
284  *
285  * The bits from (n->pos + n->bits) to (tp->pos - 1) - "S" - are skipped bits
286  * for the node n.
287  *
288  * All the bits we have seen so far are significant to the node n. The rest
289  * of the bits are really not needed or indeed known in n->key.
290  *
291  * The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
292  * n's child array, and will of course be different for each child.
293  *
294  * The rest of the bits, from 0 to (n->pos -1) - "u" - are completely unknown
295  * at this point.
296  */
297 
298 static const int halve_threshold = 25;
299 static const int inflate_threshold = 50;
300 static const int halve_threshold_root = 15;
301 static const int inflate_threshold_root = 30;
302 
303 static void __alias_free_mem(struct rcu_head *head)
304 {
305         struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
306         kmem_cache_free(fn_alias_kmem, fa);
307 }
308 
309 static inline void alias_free_mem_rcu(struct fib_alias *fa)
310 {
311         call_rcu(&fa->rcu, __alias_free_mem);
312 }
313 
314 #define TNODE_KMALLOC_MAX \
315         ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct key_vector *))
316 #define TNODE_VMALLOC_MAX \
317         ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
318 
319 static void __node_free_rcu(struct rcu_head *head)
320 {
321         struct tnode *n = container_of(head, struct tnode, rcu);
322 
323         if (!n->tn_bits)
324                 kmem_cache_free(trie_leaf_kmem, n);
325         else
326                 kvfree(n);
327 }
328 
329 #define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
330 
331 static struct tnode *tnode_alloc(int bits)
332 {
333         size_t size;
334 
335         /* verify bits is within bounds */
336         if (bits > TNODE_VMALLOC_MAX)
337                 return NULL;
338 
339         /* determine size and verify it is non-zero and didn't overflow */
340         size = TNODE_SIZE(1ul << bits);
341 
342         if (size <= PAGE_SIZE)
343                 return kzalloc(size, GFP_KERNEL);
344         else
345                 return vzalloc(size);
346 }
347 
348 static inline void empty_child_inc(struct key_vector *n)
349 {
350         ++tn_info(n)->empty_children ? : ++tn_info(n)->full_children;
351 }
352 
353 static inline void empty_child_dec(struct key_vector *n)
354 {
355         tn_info(n)->empty_children-- ? : tn_info(n)->full_children--;
356 }
357 
358 static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
359 {
360         struct key_vector *l;
361         struct tnode *kv;
362 
363         kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
364         if (!kv)
365                 return NULL;
366 
367         /* initialize key vector */
368         l = kv->kv;
369         l->key = key;
370         l->pos = 0;
371         l->bits = 0;
372         l->slen = fa->fa_slen;
373 
374         /* link leaf to fib alias */
375         INIT_HLIST_HEAD(&l->leaf);
376         hlist_add_head(&fa->fa_list, &l->leaf);
377 
378         return l;
379 }
380 
381 static struct key_vector *tnode_new(t_key key, int pos, int bits)
382 {
383         unsigned int shift = pos + bits;
384         struct key_vector *tn;
385         struct tnode *tnode;
386 
387         /* verify bits and pos their msb bits clear and values are valid */
388         BUG_ON(!bits || (shift > KEYLENGTH));
389 
390         tnode = tnode_alloc(bits);
391         if (!tnode)
392                 return NULL;
393 
394         pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
395                  sizeof(struct key_vector *) << bits);
396 
397         if (bits == KEYLENGTH)
398                 tnode->full_children = 1;
399         else
400                 tnode->empty_children = 1ul << bits;
401 
402         tn = tnode->kv;
403         tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
404         tn->pos = pos;
405         tn->bits = bits;
406         tn->slen = pos;
407 
408         return tn;
409 }
410 
411 /* Check whether a tnode 'n' is "full", i.e. it is an internal node
412  * and no bits are skipped. See discussion in dyntree paper p. 6
413  */
414 static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
415 {
416         return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
417 }
418 
419 /* Add a child at position i overwriting the old value.
420  * Update the value of full_children and empty_children.
421  */
422 static void put_child(struct key_vector *tn, unsigned long i,
423                       struct key_vector *n)
424 {
425         struct key_vector *chi = get_child(tn, i);
426         int isfull, wasfull;
427 
428         BUG_ON(i >= child_length(tn));
429 
430         /* update emptyChildren, overflow into fullChildren */
431         if (!n && chi)
432                 empty_child_inc(tn);
433         if (n && !chi)
434                 empty_child_dec(tn);
435 
436         /* update fullChildren */
437         wasfull = tnode_full(tn, chi);
438         isfull = tnode_full(tn, n);
439 
440         if (wasfull && !isfull)
441                 tn_info(tn)->full_children--;
442         else if (!wasfull && isfull)
443                 tn_info(tn)->full_children++;
444 
445         if (n && (tn->slen < n->slen))
446                 tn->slen = n->slen;
447 
448         rcu_assign_pointer(tn->tnode[i], n);
449 }
450 
451 static void update_children(struct key_vector *tn)
452 {
453         unsigned long i;
454 
455         /* update all of the child parent pointers */
456         for (i = child_length(tn); i;) {
457                 struct key_vector *inode = get_child(tn, --i);
458 
459                 if (!inode)
460                         continue;
461 
462                 /* Either update the children of a tnode that
463                  * already belongs to us or update the child
464                  * to point to ourselves.
465                  */
466                 if (node_parent(inode) == tn)
467                         update_children(inode);
468                 else
469                         node_set_parent(inode, tn);
470         }
471 }
472 
473 static inline void put_child_root(struct key_vector *tp, t_key key,
474                                   struct key_vector *n)
475 {
476         if (IS_TRIE(tp))
477                 rcu_assign_pointer(tp->tnode[0], n);
478         else
479                 put_child(tp, get_index(key, tp), n);
480 }
481 
482 static inline void tnode_free_init(struct key_vector *tn)
483 {
484         tn_info(tn)->rcu.next = NULL;
485 }
486 
487 static inline void tnode_free_append(struct key_vector *tn,
488                                      struct key_vector *n)
489 {
490         tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
491         tn_info(tn)->rcu.next = &tn_info(n)->rcu;
492 }
493 
494 static void tnode_free(struct key_vector *tn)
495 {
496         struct callback_head *head = &tn_info(tn)->rcu;
497 
498         while (head) {
499                 head = head->next;
500                 tnode_free_size += TNODE_SIZE(1ul << tn->bits);
501                 node_free(tn);
502 
503                 tn = container_of(head, struct tnode, rcu)->kv;
504         }
505 
506         if (tnode_free_size >= PAGE_SIZE * sync_pages) {
507                 tnode_free_size = 0;
508                 synchronize_rcu();
509         }
510 }
511 
512 static struct key_vector *replace(struct trie *t,
513                                   struct key_vector *oldtnode,
514                                   struct key_vector *tn)
515 {
516         struct key_vector *tp = node_parent(oldtnode);
517         unsigned long i;
518 
519         /* setup the parent pointer out of and back into this node */
520         NODE_INIT_PARENT(tn, tp);
521         put_child_root(tp, tn->key, tn);
522 
523         /* update all of the child parent pointers */
524         update_children(tn);
525 
526         /* all pointers should be clean so we are done */
527         tnode_free(oldtnode);
528 
529         /* resize children now that oldtnode is freed */
530         for (i = child_length(tn); i;) {
531                 struct key_vector *inode = get_child(tn, --i);
532 
533                 /* resize child node */
534                 if (tnode_full(tn, inode))
535                         tn = resize(t, inode);
536         }
537 
538         return tp;
539 }
540 
541 static struct key_vector *inflate(struct trie *t,
542                                   struct key_vector *oldtnode)
543 {
544         struct key_vector *tn;
545         unsigned long i;
546         t_key m;
547 
548         pr_debug("In inflate\n");
549 
550         tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
551         if (!tn)
552                 goto notnode;
553 
554         /* prepare oldtnode to be freed */
555         tnode_free_init(oldtnode);
556 
557         /* Assemble all of the pointers in our cluster, in this case that
558          * represents all of the pointers out of our allocated nodes that
559          * point to existing tnodes and the links between our allocated
560          * nodes.
561          */
562         for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
563                 struct key_vector *inode = get_child(oldtnode, --i);
564                 struct key_vector *node0, *node1;
565                 unsigned long j, k;
566 
567                 /* An empty child */
568                 if (!inode)
569                         continue;
570 
571                 /* A leaf or an internal node with skipped bits */
572                 if (!tnode_full(oldtnode, inode)) {
573                         put_child(tn, get_index(inode->key, tn), inode);
574                         continue;
575                 }
576 
577                 /* drop the node in the old tnode free list */
578                 tnode_free_append(oldtnode, inode);
579 
580                 /* An internal node with two children */
581                 if (inode->bits == 1) {
582                         put_child(tn, 2 * i + 1, get_child(inode, 1));
583                         put_child(tn, 2 * i, get_child(inode, 0));
584                         continue;
585                 }
586 
587                 /* We will replace this node 'inode' with two new
588                  * ones, 'node0' and 'node1', each with half of the
589                  * original children. The two new nodes will have
590                  * a position one bit further down the key and this
591                  * means that the "significant" part of their keys
592                  * (see the discussion near the top of this file)
593                  * will differ by one bit, which will be "" in
594                  * node0's key and "1" in node1's key. Since we are
595                  * moving the key position by one step, the bit that
596                  * we are moving away from - the bit at position
597                  * (tn->pos) - is the one that will differ between
598                  * node0 and node1. So... we synthesize that bit in the
599                  * two new keys.
600                  */
601                 node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
602                 if (!node1)
603                         goto nomem;
604                 node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
605 
606                 tnode_free_append(tn, node1);
607                 if (!node0)
608                         goto nomem;
609                 tnode_free_append(tn, node0);
610 
611                 /* populate child pointers in new nodes */
612                 for (k = child_length(inode), j = k / 2; j;) {
613                         put_child(node1, --j, get_child(inode, --k));
614                         put_child(node0, j, get_child(inode, j));
615                         put_child(node1, --j, get_child(inode, --k));
616                         put_child(node0, j, get_child(inode, j));
617                 }
618 
619                 /* link new nodes to parent */
620                 NODE_INIT_PARENT(node1, tn);
621                 NODE_INIT_PARENT(node0, tn);
622 
623                 /* link parent to nodes */
624                 put_child(tn, 2 * i + 1, node1);
625                 put_child(tn, 2 * i, node0);
626         }
627 
628         /* setup the parent pointers into and out of this node */
629         return replace(t, oldtnode, tn);
630 nomem:
631         /* all pointers should be clean so we are done */
632         tnode_free(tn);
633 notnode:
634         return NULL;
635 }
636 
637 static struct key_vector *halve(struct trie *t,
638                                 struct key_vector *oldtnode)
639 {
640         struct key_vector *tn;
641         unsigned long i;
642 
643         pr_debug("In halve\n");
644 
645         tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
646         if (!tn)
647                 goto notnode;
648 
649         /* prepare oldtnode to be freed */
650         tnode_free_init(oldtnode);
651 
652         /* Assemble all of the pointers in our cluster, in this case that
653          * represents all of the pointers out of our allocated nodes that
654          * point to existing tnodes and the links between our allocated
655          * nodes.
656          */
657         for (i = child_length(oldtnode); i;) {
658                 struct key_vector *node1 = get_child(oldtnode, --i);
659                 struct key_vector *node0 = get_child(oldtnode, --i);
660                 struct key_vector *inode;
661 
662                 /* At least one of the children is empty */
663                 if (!node1 || !node0) {
664                         put_child(tn, i / 2, node1 ? : node0);
665                         continue;
666                 }
667 
668                 /* Two nonempty children */
669                 inode = tnode_new(node0->key, oldtnode->pos, 1);
670                 if (!inode)
671                         goto nomem;
672                 tnode_free_append(tn, inode);
673 
674                 /* initialize pointers out of node */
675                 put_child(inode, 1, node1);
676                 put_child(inode, 0, node0);
677                 NODE_INIT_PARENT(inode, tn);
678 
679                 /* link parent to node */
680                 put_child(tn, i / 2, inode);
681         }
682 
683         /* setup the parent pointers into and out of this node */
684         return replace(t, oldtnode, tn);
685 nomem:
686         /* all pointers should be clean so we are done */
687         tnode_free(tn);
688 notnode:
689         return NULL;
690 }
691 
692 static struct key_vector *collapse(struct trie *t,
693                                    struct key_vector *oldtnode)
694 {
695         struct key_vector *n, *tp;
696         unsigned long i;
697 
698         /* scan the tnode looking for that one child that might still exist */
699         for (n = NULL, i = child_length(oldtnode); !n && i;)
700                 n = get_child(oldtnode, --i);
701 
702         /* compress one level */
703         tp = node_parent(oldtnode);
704         put_child_root(tp, oldtnode->key, n);
705         node_set_parent(n, tp);
706 
707         /* drop dead node */
708         node_free(oldtnode);
709 
710         return tp;
711 }
712 
713 static unsigned char update_suffix(struct key_vector *tn)
714 {
715         unsigned char slen = tn->pos;
716         unsigned long stride, i;
717         unsigned char slen_max;
718 
719         /* only vector 0 can have a suffix length greater than or equal to
720          * tn->pos + tn->bits, the second highest node will have a suffix
721          * length at most of tn->pos + tn->bits - 1
722          */
723         slen_max = min_t(unsigned char, tn->pos + tn->bits - 1, tn->slen);
724 
725         /* search though the list of children looking for nodes that might
726          * have a suffix greater than the one we currently have.  This is
727          * why we start with a stride of 2 since a stride of 1 would
728          * represent the nodes with suffix length equal to tn->pos
729          */
730         for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
731                 struct key_vector *n = get_child(tn, i);
732 
733                 if (!n || (n->slen <= slen))
734                         continue;
735 
736                 /* update stride and slen based on new value */
737                 stride <<= (n->slen - slen);
738                 slen = n->slen;
739                 i &= ~(stride - 1);
740 
741                 /* stop searching if we have hit the maximum possible value */
742                 if (slen >= slen_max)
743                         break;
744         }
745 
746         tn->slen = slen;
747 
748         return slen;
749 }
750 
751 /* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
752  * the Helsinki University of Technology and Matti Tikkanen of Nokia
753  * Telecommunications, page 6:
754  * "A node is doubled if the ratio of non-empty children to all
755  * children in the *doubled* node is at least 'high'."
756  *
757  * 'high' in this instance is the variable 'inflate_threshold'. It
758  * is expressed as a percentage, so we multiply it with
759  * child_length() and instead of multiplying by 2 (since the
760  * child array will be doubled by inflate()) and multiplying
761  * the left-hand side by 100 (to handle the percentage thing) we
762  * multiply the left-hand side by 50.
763  *
764  * The left-hand side may look a bit weird: child_length(tn)
765  * - tn->empty_children is of course the number of non-null children
766  * in the current node. tn->full_children is the number of "full"
767  * children, that is non-null tnodes with a skip value of 0.
768  * All of those will be doubled in the resulting inflated tnode, so
769  * we just count them one extra time here.
770  *
771  * A clearer way to write this would be:
772  *
773  * to_be_doubled = tn->full_children;
774  * not_to_be_doubled = child_length(tn) - tn->empty_children -
775  *     tn->full_children;
776  *
777  * new_child_length = child_length(tn) * 2;
778  *
779  * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
780  *      new_child_length;
781  * if (new_fill_factor >= inflate_threshold)
782  *
783  * ...and so on, tho it would mess up the while () loop.
784  *
785  * anyway,
786  * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
787  *      inflate_threshold
788  *
789  * avoid a division:
790  * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
791  *      inflate_threshold * new_child_length
792  *
793  * expand not_to_be_doubled and to_be_doubled, and shorten:
794  * 100 * (child_length(tn) - tn->empty_children +
795  *    tn->full_children) >= inflate_threshold * new_child_length
796  *
797  * expand new_child_length:
798  * 100 * (child_length(tn) - tn->empty_children +
799  *    tn->full_children) >=
800  *      inflate_threshold * child_length(tn) * 2
801  *
802  * shorten again:
803  * 50 * (tn->full_children + child_length(tn) -
804  *    tn->empty_children) >= inflate_threshold *
805  *    child_length(tn)
806  *
807  */
808 static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
809 {
810         unsigned long used = child_length(tn);
811         unsigned long threshold = used;
812 
813         /* Keep root node larger */
814         threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
815         used -= tn_info(tn)->empty_children;
816         used += tn_info(tn)->full_children;
817 
818         /* if bits == KEYLENGTH then pos = 0, and will fail below */
819 
820         return (used > 1) && tn->pos && ((50 * used) >= threshold);
821 }
822 
823 static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
824 {
825         unsigned long used = child_length(tn);
826         unsigned long threshold = used;
827 
828         /* Keep root node larger */
829         threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
830         used -= tn_info(tn)->empty_children;
831 
832         /* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
833 
834         return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
835 }
836 
837 static inline bool should_collapse(struct key_vector *tn)
838 {
839         unsigned long used = child_length(tn);
840 
841         used -= tn_info(tn)->empty_children;
842 
843         /* account for bits == KEYLENGTH case */
844         if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
845                 used -= KEY_MAX;
846 
847         /* One child or none, time to drop us from the trie */
848         return used < 2;
849 }
850 
851 #define MAX_WORK 10
852 static struct key_vector *resize(struct trie *t, struct key_vector *tn)
853 {
854 #ifdef CONFIG_IP_FIB_TRIE_STATS
855         struct trie_use_stats __percpu *stats = t->stats;
856 #endif
857         struct key_vector *tp = node_parent(tn);
858         unsigned long cindex = get_index(tn->key, tp);
859         int max_work = MAX_WORK;
860 
861         pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
862                  tn, inflate_threshold, halve_threshold);
863 
864         /* track the tnode via the pointer from the parent instead of
865          * doing it ourselves.  This way we can let RCU fully do its
866          * thing without us interfering
867          */
868         BUG_ON(tn != get_child(tp, cindex));
869 
870         /* Double as long as the resulting node has a number of
871          * nonempty nodes that are above the threshold.
872          */
873         while (should_inflate(tp, tn) && max_work) {
874                 tp = inflate(t, tn);
875                 if (!tp) {
876 #ifdef CONFIG_IP_FIB_TRIE_STATS
877                         this_cpu_inc(stats->resize_node_skipped);
878 #endif
879                         break;
880                 }
881 
882                 max_work--;
883                 tn = get_child(tp, cindex);
884         }
885 
886         /* update parent in case inflate failed */
887         tp = node_parent(tn);
888 
889         /* Return if at least one inflate is run */
890         if (max_work != MAX_WORK)
891                 return tp;
892 
893         /* Halve as long as the number of empty children in this
894          * node is above threshold.
895          */
896         while (should_halve(tp, tn) && max_work) {
897                 tp = halve(t, tn);
898                 if (!tp) {
899 #ifdef CONFIG_IP_FIB_TRIE_STATS
900                         this_cpu_inc(stats->resize_node_skipped);
901 #endif
902                         break;
903                 }
904 
905                 max_work--;
906                 tn = get_child(tp, cindex);
907         }
908 
909         /* Only one child remains */
910         if (should_collapse(tn))
911                 return collapse(t, tn);
912 
913         /* update parent in case halve failed */
914         return node_parent(tn);
915 }
916 
917 static void node_pull_suffix(struct key_vector *tn, unsigned char slen)
918 {
919         unsigned char node_slen = tn->slen;
920 
921         while ((node_slen > tn->pos) && (node_slen > slen)) {
922                 slen = update_suffix(tn);
923                 if (node_slen == slen)
924                         break;
925 
926                 tn = node_parent(tn);
927                 node_slen = tn->slen;
928         }
929 }
930 
931 static void node_push_suffix(struct key_vector *tn, unsigned char slen)
932 {
933         while (tn->slen < slen) {
934                 tn->slen = slen;
935                 tn = node_parent(tn);
936         }
937 }
938 
939 /* rcu_read_lock needs to be hold by caller from readside */
940 static struct key_vector *fib_find_node(struct trie *t,
941                                         struct key_vector **tp, u32 key)
942 {
943         struct key_vector *pn, *n = t->kv;
944         unsigned long index = 0;
945 
946         do {
947                 pn = n;
948                 n = get_child_rcu(n, index);
949 
950                 if (!n)
951                         break;
952 
953                 index = get_cindex(key, n);
954 
955                 /* This bit of code is a bit tricky but it combines multiple
956                  * checks into a single check.  The prefix consists of the
957                  * prefix plus zeros for the bits in the cindex. The index
958                  * is the difference between the key and this value.  From
959                  * this we can actually derive several pieces of data.
960                  *   if (index >= (1ul << bits))
961                  *     we have a mismatch in skip bits and failed
962                  *   else
963                  *     we know the value is cindex
964                  *
965                  * This check is safe even if bits == KEYLENGTH due to the
966                  * fact that we can only allocate a node with 32 bits if a
967                  * long is greater than 32 bits.
968                  */
969                 if (index >= (1ul << n->bits)) {
970                         n = NULL;
971                         break;
972                 }
973 
974                 /* keep searching until we find a perfect match leaf or NULL */
975         } while (IS_TNODE(n));
976 
977         *tp = pn;
978 
979         return n;
980 }
981 
982 /* Return the first fib alias matching TOS with
983  * priority less than or equal to PRIO.
984  */
985 static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
986                                         u8 tos, u32 prio, u32 tb_id)
987 {
988         struct fib_alias *fa;
989 
990         if (!fah)
991                 return NULL;
992 
993         hlist_for_each_entry(fa, fah, fa_list) {
994                 if (fa->fa_slen < slen)
995                         continue;
996                 if (fa->fa_slen != slen)
997                         break;
998                 if (fa->tb_id > tb_id)
999                         continue;
1000                 if (fa->tb_id != tb_id)
1001                         break;
1002                 if (fa->fa_tos > tos)
1003                         continue;
1004                 if (fa->fa_info->fib_priority >= prio || fa->fa_tos < tos)
1005                         return fa;
1006         }
1007 
1008         return NULL;
1009 }
1010 
1011 static void trie_rebalance(struct trie *t, struct key_vector *tn)
1012 {
1013         while (!IS_TRIE(tn))
1014                 tn = resize(t, tn);
1015 }
1016 
1017 static int fib_insert_node(struct trie *t, struct key_vector *tp,
1018                            struct fib_alias *new, t_key key)
1019 {
1020         struct key_vector *n, *l;
1021 
1022         l = leaf_new(key, new);
1023         if (!l)
1024                 goto noleaf;
1025 
1026         /* retrieve child from parent node */
1027         n = get_child(tp, get_index(key, tp));
1028 
1029         /* Case 2: n is a LEAF or a TNODE and the key doesn't match.
1030          *
1031          *  Add a new tnode here
1032          *  first tnode need some special handling
1033          *  leaves us in position for handling as case 3
1034          */
1035         if (n) {
1036                 struct key_vector *tn;
1037 
1038                 tn = tnode_new(key, __fls(key ^ n->key), 1);
1039                 if (!tn)
1040                         goto notnode;
1041 
1042                 /* initialize routes out of node */
1043                 NODE_INIT_PARENT(tn, tp);
1044                 put_child(tn, get_index(key, tn) ^ 1, n);
1045 
1046                 /* start adding routes into the node */
1047                 put_child_root(tp, key, tn);
1048                 node_set_parent(n, tn);
1049 
1050                 /* parent now has a NULL spot where the leaf can go */
1051                 tp = tn;
1052         }
1053 
1054         /* Case 3: n is NULL, and will just insert a new leaf */
1055         node_push_suffix(tp, new->fa_slen);
1056         NODE_INIT_PARENT(l, tp);
1057         put_child_root(tp, key, l);
1058         trie_rebalance(t, tp);
1059 
1060         return 0;
1061 notnode:
1062         node_free(l);
1063 noleaf:
1064         return -ENOMEM;
1065 }
1066 
1067 static int fib_insert_alias(struct trie *t, struct key_vector *tp,
1068                             struct key_vector *l, struct fib_alias *new,
1069                             struct fib_alias *fa, t_key key)
1070 {
1071         if (!l)
1072                 return fib_insert_node(t, tp, new, key);
1073 
1074         if (fa) {
1075                 hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
1076         } else {
1077                 struct fib_alias *last;
1078 
1079                 hlist_for_each_entry(last, &l->leaf, fa_list) {
1080                         if (new->fa_slen < last->fa_slen)
1081                                 break;
1082                         if ((new->fa_slen == last->fa_slen) &&
1083                             (new->tb_id > last->tb_id))
1084                                 break;
1085                         fa = last;
1086                 }
1087 
1088                 if (fa)
1089                         hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
1090                 else
1091                         hlist_add_head_rcu(&new->fa_list, &l->leaf);
1092         }
1093 
1094         /* if we added to the tail node then we need to update slen */
1095         if (l->slen < new->fa_slen) {
1096                 l->slen = new->fa_slen;
1097                 node_push_suffix(tp, new->fa_slen);
1098         }
1099 
1100         return 0;
1101 }
1102 
1103 static bool fib_valid_key_len(u32 key, u8 plen, struct netlink_ext_ack *extack)
1104 {
1105         if (plen > KEYLENGTH) {
1106                 NL_SET_ERR_MSG(extack, "Invalid prefix length");
1107                 return false;
1108         }
1109 
1110         if ((plen < KEYLENGTH) && (key << plen)) {
1111                 NL_SET_ERR_MSG(extack,
1112                                "Invalid prefix for given prefix length");
1113                 return false;
1114         }
1115 
1116         return true;
1117 }
1118 
1119 /* Caller must hold RTNL. */
1120 int fib_table_insert(struct net *net, struct fib_table *tb,
1121                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1122 {
1123         enum fib_event_type event = FIB_EVENT_ENTRY_ADD;
1124         struct trie *t = (struct trie *)tb->tb_data;
1125         struct fib_alias *fa, *new_fa;
1126         struct key_vector *l, *tp;
1127         u16 nlflags = NLM_F_EXCL;
1128         struct fib_info *fi;
1129         u8 plen = cfg->fc_dst_len;
1130         u8 slen = KEYLENGTH - plen;
1131         u8 tos = cfg->fc_tos;
1132         u32 key;
1133         int err;
1134 
1135         key = ntohl(cfg->fc_dst);
1136 
1137         if (!fib_valid_key_len(key, plen, extack))
1138                 return -EINVAL;
1139 
1140         pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
1141 
1142         fi = fib_create_info(cfg, extack);
1143         if (IS_ERR(fi)) {
1144                 err = PTR_ERR(fi);
1145                 goto err;
1146         }
1147 
1148         l = fib_find_node(t, &tp, key);
1149         fa = l ? fib_find_alias(&l->leaf, slen, tos, fi->fib_priority,
1150                                 tb->tb_id) : NULL;
1151 
1152         /* Now fa, if non-NULL, points to the first fib alias
1153          * with the same keys [prefix,tos,priority], if such key already
1154          * exists or to the node before which we will insert new one.
1155          *
1156          * If fa is NULL, we will need to allocate a new one and
1157          * insert to the tail of the section matching the suffix length
1158          * of the new alias.
1159          */
1160 
1161         if (fa && fa->fa_tos == tos &&
1162             fa->fa_info->fib_priority == fi->fib_priority) {
1163                 struct fib_alias *fa_first, *fa_match;
1164 
1165                 err = -EEXIST;
1166                 if (cfg->fc_nlflags & NLM_F_EXCL)
1167                         goto out;
1168 
1169                 nlflags &= ~NLM_F_EXCL;
1170 
1171                 /* We have 2 goals:
1172                  * 1. Find exact match for type, scope, fib_info to avoid
1173                  * duplicate routes
1174                  * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
1175                  */
1176                 fa_match = NULL;
1177                 fa_first = fa;
1178                 hlist_for_each_entry_from(fa, fa_list) {
1179                         if ((fa->fa_slen != slen) ||
1180                             (fa->tb_id != tb->tb_id) ||
1181                             (fa->fa_tos != tos))
1182                                 break;
1183                         if (fa->fa_info->fib_priority != fi->fib_priority)
1184                                 break;
1185                         if (fa->fa_type == cfg->fc_type &&
1186                             fa->fa_info == fi) {
1187                                 fa_match = fa;
1188                                 break;
1189                         }
1190                 }
1191 
1192                 if (cfg->fc_nlflags & NLM_F_REPLACE) {
1193                         struct fib_info *fi_drop;
1194                         u8 state;
1195 
1196                         nlflags |= NLM_F_REPLACE;
1197                         fa = fa_first;
1198                         if (fa_match) {
1199                                 if (fa == fa_match)
1200                                         err = 0;
1201                                 goto out;
1202                         }
1203                         err = -ENOBUFS;
1204                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1205                         if (!new_fa)
1206                                 goto out;
1207 
1208                         fi_drop = fa->fa_info;
1209                         new_fa->fa_tos = fa->fa_tos;
1210                         new_fa->fa_info = fi;
1211                         new_fa->fa_type = cfg->fc_type;
1212                         state = fa->fa_state;
1213                         new_fa->fa_state = state & ~FA_S_ACCESSED;
1214                         new_fa->fa_slen = fa->fa_slen;
1215                         new_fa->tb_id = tb->tb_id;
1216                         new_fa->fa_default = -1;
1217 
1218                         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_REPLACE,
1219                                                  key, plen, new_fa, extack);
1220                         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
1221                                   tb->tb_id, &cfg->fc_nlinfo, nlflags);
1222 
1223                         hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
1224 
1225                         alias_free_mem_rcu(fa);
1226 
1227                         fib_release_info(fi_drop);
1228                         if (state & FA_S_ACCESSED)
1229                                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1230 
1231                         goto succeeded;
1232                 }
1233                 /* Error if we find a perfect match which
1234                  * uses the same scope, type, and nexthop
1235                  * information.
1236                  */
1237                 if (fa_match)
1238                         goto out;
1239 
1240                 if (cfg->fc_nlflags & NLM_F_APPEND) {
1241                         event = FIB_EVENT_ENTRY_APPEND;
1242                         nlflags |= NLM_F_APPEND;
1243                 } else {
1244                         fa = fa_first;
1245                 }
1246         }
1247         err = -ENOENT;
1248         if (!(cfg->fc_nlflags & NLM_F_CREATE))
1249                 goto out;
1250 
1251         nlflags |= NLM_F_CREATE;
1252         err = -ENOBUFS;
1253         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1254         if (!new_fa)
1255                 goto out;
1256 
1257         new_fa->fa_info = fi;
1258         new_fa->fa_tos = tos;
1259         new_fa->fa_type = cfg->fc_type;
1260         new_fa->fa_state = 0;
1261         new_fa->fa_slen = slen;
1262         new_fa->tb_id = tb->tb_id;
1263         new_fa->fa_default = -1;
1264 
1265         /* Insert new entry to the list. */
1266         err = fib_insert_alias(t, tp, l, new_fa, fa, key);
1267         if (err)
1268                 goto out_free_new_fa;
1269 
1270         if (!plen)
1271                 tb->tb_num_default++;
1272 
1273         rt_cache_flush(cfg->fc_nlinfo.nl_net);
1274         call_fib_entry_notifiers(net, event, key, plen, new_fa, extack);
1275         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
1276                   &cfg->fc_nlinfo, nlflags);
1277 succeeded:
1278         return 0;
1279 
1280 out_free_new_fa:
1281         kmem_cache_free(fn_alias_kmem, new_fa);
1282 out:
1283         fib_release_info(fi);
1284 err:
1285         return err;
1286 }
1287 
1288 static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
1289 {
1290         t_key prefix = n->key;
1291 
1292         return (key ^ prefix) & (prefix | -prefix);
1293 }
1294 
1295 /* should be called with rcu_read_lock */
1296 int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
1297                      struct fib_result *res, int fib_flags)
1298 {
1299         struct trie *t = (struct trie *) tb->tb_data;
1300 #ifdef CONFIG_IP_FIB_TRIE_STATS
1301         struct trie_use_stats __percpu *stats = t->stats;
1302 #endif
1303         const t_key key = ntohl(flp->daddr);
1304         struct key_vector *n, *pn;
1305         struct fib_alias *fa;
1306         unsigned long index;
1307         t_key cindex;
1308 
1309         trace_fib_table_lookup(tb->tb_id, flp);
1310 
1311         pn = t->kv;
1312         cindex = 0;
1313 
1314         n = get_child_rcu(pn, cindex);
1315         if (!n)
1316                 return -EAGAIN;
1317 
1318 #ifdef CONFIG_IP_FIB_TRIE_STATS
1319         this_cpu_inc(stats->gets);
1320 #endif
1321 
1322         /* Step 1: Travel to the longest prefix match in the trie */
1323         for (;;) {
1324                 index = get_cindex(key, n);
1325 
1326                 /* This bit of code is a bit tricky but it combines multiple
1327                  * checks into a single check.  The prefix consists of the
1328                  * prefix plus zeros for the "bits" in the prefix. The index
1329                  * is the difference between the key and this value.  From
1330                  * this we can actually derive several pieces of data.
1331                  *   if (index >= (1ul << bits))
1332                  *     we have a mismatch in skip bits and failed
1333                  *   else
1334                  *     we know the value is cindex
1335                  *
1336                  * This check is safe even if bits == KEYLENGTH due to the
1337                  * fact that we can only allocate a node with 32 bits if a
1338                  * long is greater than 32 bits.
1339                  */
1340                 if (index >= (1ul << n->bits))
1341                         break;
1342 
1343                 /* we have found a leaf. Prefixes have already been compared */
1344                 if (IS_LEAF(n))
1345                         goto found;
1346 
1347                 /* only record pn and cindex if we are going to be chopping
1348                  * bits later.  Otherwise we are just wasting cycles.
1349                  */
1350                 if (n->slen > n->pos) {
1351                         pn = n;
1352                         cindex = index;
1353                 }
1354 
1355                 n = get_child_rcu(n, index);
1356                 if (unlikely(!n))
1357                         goto backtrace;
1358         }
1359 
1360         /* Step 2: Sort out leaves and begin backtracing for longest prefix */
1361         for (;;) {
1362                 /* record the pointer where our next node pointer is stored */
1363                 struct key_vector __rcu **cptr = n->tnode;
1364 
1365                 /* This test verifies that none of the bits that differ
1366                  * between the key and the prefix exist in the region of
1367                  * the lsb and higher in the prefix.
1368                  */
1369                 if (unlikely(prefix_mismatch(key, n)) || (n->slen == n->pos))
1370                         goto backtrace;
1371 
1372                 /* exit out and process leaf */
1373                 if (unlikely(IS_LEAF(n)))
1374                         break;
1375 
1376                 /* Don't bother recording parent info.  Since we are in
1377                  * prefix match mode we will have to come back to wherever
1378                  * we started this traversal anyway
1379                  */
1380 
1381                 while ((n = rcu_dereference(*cptr)) == NULL) {
1382 backtrace:
1383 #ifdef CONFIG_IP_FIB_TRIE_STATS
1384                         if (!n)
1385                                 this_cpu_inc(stats->null_node_hit);
1386 #endif
1387                         /* If we are at cindex 0 there are no more bits for
1388                          * us to strip at this level so we must ascend back
1389                          * up one level to see if there are any more bits to
1390                          * be stripped there.
1391                          */
1392                         while (!cindex) {
1393                                 t_key pkey = pn->key;
1394 
1395                                 /* If we don't have a parent then there is
1396                                  * nothing for us to do as we do not have any
1397                                  * further nodes to parse.
1398                                  */
1399                                 if (IS_TRIE(pn))
1400                                         return -EAGAIN;
1401 #ifdef CONFIG_IP_FIB_TRIE_STATS
1402                                 this_cpu_inc(stats->backtrack);
1403 #endif
1404                                 /* Get Child's index */
1405                                 pn = node_parent_rcu(pn);
1406                                 cindex = get_index(pkey, pn);
1407                         }
1408 
1409                         /* strip the least significant bit from the cindex */
1410                         cindex &= cindex - 1;
1411 
1412                         /* grab pointer for next child node */
1413                         cptr = &pn->tnode[cindex];
1414                 }
1415         }
1416 
1417 found:
1418         /* this line carries forward the xor from earlier in the function */
1419         index = key ^ n->key;
1420 
1421         /* Step 3: Process the leaf, if that fails fall back to backtracing */
1422         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
1423                 struct fib_info *fi = fa->fa_info;
1424                 int nhsel, err;
1425 
1426                 if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) {
1427                         if (index >= (1ul << fa->fa_slen))
1428                                 continue;
1429                 }
1430                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1431                         continue;
1432                 if (fi->fib_dead)
1433                         continue;
1434                 if (fa->fa_info->fib_scope < flp->flowi4_scope)
1435                         continue;
1436                 fib_alias_accessed(fa);
1437                 err = fib_props[fa->fa_type].error;
1438                 if (unlikely(err < 0)) {
1439 #ifdef CONFIG_IP_FIB_TRIE_STATS
1440                         this_cpu_inc(stats->semantic_match_passed);
1441 #endif
1442                         return err;
1443                 }
1444                 if (fi->fib_flags & RTNH_F_DEAD)
1445                         continue;
1446                 for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
1447                         const struct fib_nh *nh = &fi->fib_nh[nhsel];
1448                         struct in_device *in_dev = __in_dev_get_rcu(nh->nh_dev);
1449 
1450                         if (nh->nh_flags & RTNH_F_DEAD)
1451                                 continue;
1452                         if (in_dev &&
1453                             IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1454                             nh->nh_flags & RTNH_F_LINKDOWN &&
1455                             !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
1456                                 continue;
1457                         if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) {
1458                                 if (flp->flowi4_oif &&
1459                                     flp->flowi4_oif != nh->nh_oif)
1460                                         continue;
1461                         }
1462 
1463                         if (!(fib_flags & FIB_LOOKUP_NOREF))
1464                                 refcount_inc(&fi->fib_clntref);
1465 
1466                         res->prefix = htonl(n->key);
1467                         res->prefixlen = KEYLENGTH - fa->fa_slen;
1468                         res->nh_sel = nhsel;
1469                         res->type = fa->fa_type;
1470                         res->scope = fi->fib_scope;
1471                         res->fi = fi;
1472                         res->table = tb;
1473                         res->fa_head = &n->leaf;
1474 #ifdef CONFIG_IP_FIB_TRIE_STATS
1475                         this_cpu_inc(stats->semantic_match_passed);
1476 #endif
1477                         trace_fib_table_lookup_nh(nh);
1478 
1479                         return err;
1480                 }
1481         }
1482 #ifdef CONFIG_IP_FIB_TRIE_STATS
1483         this_cpu_inc(stats->semantic_match_miss);
1484 #endif
1485         goto backtrace;
1486 }
1487 EXPORT_SYMBOL_GPL(fib_table_lookup);
1488 
1489 static void fib_remove_alias(struct trie *t, struct key_vector *tp,
1490                              struct key_vector *l, struct fib_alias *old)
1491 {
1492         /* record the location of the previous list_info entry */
1493         struct hlist_node **pprev = old->fa_list.pprev;
1494         struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
1495 
1496         /* remove the fib_alias from the list */
1497         hlist_del_rcu(&old->fa_list);
1498 
1499         /* if we emptied the list this leaf will be freed and we can sort
1500          * out parent suffix lengths as a part of trie_rebalance
1501          */
1502         if (hlist_empty(&l->leaf)) {
1503                 if (tp->slen == l->slen)
1504                         node_pull_suffix(tp, tp->pos);
1505                 put_child_root(tp, l->key, NULL);
1506                 node_free(l);
1507                 trie_rebalance(t, tp);
1508                 return;
1509         }
1510 
1511         /* only access fa if it is pointing at the last valid hlist_node */
1512         if (*pprev)
1513                 return;
1514 
1515         /* update the trie with the latest suffix length */
1516         l->slen = fa->fa_slen;
1517         node_pull_suffix(tp, fa->fa_slen);
1518 }
1519 
1520 /* Caller must hold RTNL. */
1521 int fib_table_delete(struct net *net, struct fib_table *tb,
1522                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1523 {
1524         struct trie *t = (struct trie *) tb->tb_data;
1525         struct fib_alias *fa, *fa_to_delete;
1526         struct key_vector *l, *tp;
1527         u8 plen = cfg->fc_dst_len;
1528         u8 slen = KEYLENGTH - plen;
1529         u8 tos = cfg->fc_tos;
1530         u32 key;
1531 
1532         key = ntohl(cfg->fc_dst);
1533 
1534         if (!fib_valid_key_len(key, plen, extack))
1535                 return -EINVAL;
1536 
1537         l = fib_find_node(t, &tp, key);
1538         if (!l)
1539                 return -ESRCH;
1540 
1541         fa = fib_find_alias(&l->leaf, slen, tos, 0, tb->tb_id);
1542         if (!fa)
1543                 return -ESRCH;
1544 
1545         pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
1546 
1547         fa_to_delete = NULL;
1548         hlist_for_each_entry_from(fa, fa_list) {
1549                 struct fib_info *fi = fa->fa_info;
1550 
1551                 if ((fa->fa_slen != slen) ||
1552                     (fa->tb_id != tb->tb_id) ||
1553                     (fa->fa_tos != tos))
1554                         break;
1555 
1556                 if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
1557                     (cfg->fc_scope == RT_SCOPE_NOWHERE ||
1558                      fa->fa_info->fib_scope == cfg->fc_scope) &&
1559                     (!cfg->fc_prefsrc ||
1560                      fi->fib_prefsrc == cfg->fc_prefsrc) &&
1561                     (!cfg->fc_protocol ||
1562                      fi->fib_protocol == cfg->fc_protocol) &&
1563                     fib_nh_match(cfg, fi, extack) == 0 &&
1564                     fib_metrics_match(cfg, fi)) {
1565                         fa_to_delete = fa;
1566                         break;
1567                 }
1568         }
1569 
1570         if (!fa_to_delete)
1571                 return -ESRCH;
1572 
1573         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key, plen,
1574                                  fa_to_delete, extack);
1575         rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
1576                   &cfg->fc_nlinfo, 0);
1577 
1578         if (!plen)
1579                 tb->tb_num_default--;
1580 
1581         fib_remove_alias(t, tp, l, fa_to_delete);
1582 
1583         if (fa_to_delete->fa_state & FA_S_ACCESSED)
1584                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1585 
1586         fib_release_info(fa_to_delete->fa_info);
1587         alias_free_mem_rcu(fa_to_delete);
1588         return 0;
1589 }
1590 
1591 /* Scan for the next leaf starting at the provided key value */
1592 static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
1593 {
1594         struct key_vector *pn, *n = *tn;
1595         unsigned long cindex;
1596 
1597         /* this loop is meant to try and find the key in the trie */
1598         do {
1599                 /* record parent and next child index */
1600                 pn = n;
1601                 cindex = (key > pn->key) ? get_index(key, pn) : 0;
1602 
1603                 if (cindex >> pn->bits)
1604                         break;
1605 
1606                 /* descend into the next child */
1607                 n = get_child_rcu(pn, cindex++);
1608                 if (!n)
1609                         break;
1610 
1611                 /* guarantee forward progress on the keys */
1612                 if (IS_LEAF(n) && (n->key >= key))
1613                         goto found;
1614         } while (IS_TNODE(n));
1615 
1616         /* this loop will search for the next leaf with a greater key */
1617         while (!IS_TRIE(pn)) {
1618                 /* if we exhausted the parent node we will need to climb */
1619                 if (cindex >= (1ul << pn->bits)) {
1620                         t_key pkey = pn->key;
1621 
1622                         pn = node_parent_rcu(pn);
1623                         cindex = get_index(pkey, pn) + 1;
1624                         continue;
1625                 }
1626 
1627                 /* grab the next available node */
1628                 n = get_child_rcu(pn, cindex++);
1629                 if (!n)
1630                         continue;
1631 
1632                 /* no need to compare keys since we bumped the index */
1633                 if (IS_LEAF(n))
1634                         goto found;
1635 
1636                 /* Rescan start scanning in new node */
1637                 pn = n;
1638                 cindex = 0;
1639         }
1640 
1641         *tn = pn;
1642         return NULL; /* Root of trie */
1643 found:
1644         /* if we are at the limit for keys just return NULL for the tnode */
1645         *tn = pn;
1646         return n;
1647 }
1648 
1649 static void fib_trie_free(struct fib_table *tb)
1650 {
1651         struct trie *t = (struct trie *)tb->tb_data;
1652         struct key_vector *pn = t->kv;
1653         unsigned long cindex = 1;
1654         struct hlist_node *tmp;
1655         struct fib_alias *fa;
1656 
1657         /* walk trie in reverse order and free everything */
1658         for (;;) {
1659                 struct key_vector *n;
1660 
1661                 if (!(cindex--)) {
1662                         t_key pkey = pn->key;
1663 
1664                         if (IS_TRIE(pn))
1665                                 break;
1666 
1667                         n = pn;
1668                         pn = node_parent(pn);
1669 
1670                         /* drop emptied tnode */
1671                         put_child_root(pn, n->key, NULL);
1672                         node_free(n);
1673 
1674                         cindex = get_index(pkey, pn);
1675 
1676                         continue;
1677                 }
1678 
1679                 /* grab the next available node */
1680                 n = get_child(pn, cindex);
1681                 if (!n)
1682                         continue;
1683 
1684                 if (IS_TNODE(n)) {
1685                         /* record pn and cindex for leaf walking */
1686                         pn = n;
1687                         cindex = 1ul << n->bits;
1688 
1689                         continue;
1690                 }
1691 
1692                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1693                         hlist_del_rcu(&fa->fa_list);
1694                         alias_free_mem_rcu(fa);
1695                 }
1696 
1697                 put_child_root(pn, n->key, NULL);
1698                 node_free(n);
1699         }
1700 
1701 #ifdef CONFIG_IP_FIB_TRIE_STATS
1702         free_percpu(t->stats);
1703 #endif
1704         kfree(tb);
1705 }
1706 
1707 struct fib_table *fib_trie_unmerge(struct fib_table *oldtb)
1708 {
1709         struct trie *ot = (struct trie *)oldtb->tb_data;
1710         struct key_vector *l, *tp = ot->kv;
1711         struct fib_table *local_tb;
1712         struct fib_alias *fa;
1713         struct trie *lt;
1714         t_key key = 0;
1715 
1716         if (oldtb->tb_data == oldtb->__data)
1717                 return oldtb;
1718 
1719         local_tb = fib_trie_table(RT_TABLE_LOCAL, NULL);
1720         if (!local_tb)
1721                 return NULL;
1722 
1723         lt = (struct trie *)local_tb->tb_data;
1724 
1725         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1726                 struct key_vector *local_l = NULL, *local_tp;
1727 
1728                 hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1729                         struct fib_alias *new_fa;
1730 
1731                         if (local_tb->tb_id != fa->tb_id)
1732                                 continue;
1733 
1734                         /* clone fa for new local table */
1735                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1736                         if (!new_fa)
1737                                 goto out;
1738 
1739                         memcpy(new_fa, fa, sizeof(*fa));
1740 
1741                         /* insert clone into table */
1742                         if (!local_l)
1743                                 local_l = fib_find_node(lt, &local_tp, l->key);
1744 
1745                         if (fib_insert_alias(lt, local_tp, local_l, new_fa,
1746                                              NULL, l->key)) {
1747                                 kmem_cache_free(fn_alias_kmem, new_fa);
1748                                 goto out;
1749                         }
1750                 }
1751 
1752                 /* stop loop if key wrapped back to 0 */
1753                 key = l->key + 1;
1754                 if (key < l->key)
1755                         break;
1756         }
1757 
1758         return local_tb;
1759 out:
1760         fib_trie_free(local_tb);
1761 
1762         return NULL;
1763 }
1764 
1765 /* Caller must hold RTNL */
1766 void fib_table_flush_external(struct fib_table *tb)
1767 {
1768         struct trie *t = (struct trie *)tb->tb_data;
1769         struct key_vector *pn = t->kv;
1770         unsigned long cindex = 1;
1771         struct hlist_node *tmp;
1772         struct fib_alias *fa;
1773 
1774         /* walk trie in reverse order */
1775         for (;;) {
1776                 unsigned char slen = 0;
1777                 struct key_vector *n;
1778 
1779                 if (!(cindex--)) {
1780                         t_key pkey = pn->key;
1781 
1782                         /* cannot resize the trie vector */
1783                         if (IS_TRIE(pn))
1784                                 break;
1785 
1786                         /* update the suffix to address pulled leaves */
1787                         if (pn->slen > pn->pos)
1788                                 update_suffix(pn);
1789 
1790                         /* resize completed node */
1791                         pn = resize(t, pn);
1792                         cindex = get_index(pkey, pn);
1793 
1794                         continue;
1795                 }
1796 
1797                 /* grab the next available node */
1798                 n = get_child(pn, cindex);
1799                 if (!n)
1800                         continue;
1801 
1802                 if (IS_TNODE(n)) {
1803                         /* record pn and cindex for leaf walking */
1804                         pn = n;
1805                         cindex = 1ul << n->bits;
1806 
1807                         continue;
1808                 }
1809 
1810                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1811                         /* if alias was cloned to local then we just
1812                          * need to remove the local copy from main
1813                          */
1814                         if (tb->tb_id != fa->tb_id) {
1815                                 hlist_del_rcu(&fa->fa_list);
1816                                 alias_free_mem_rcu(fa);
1817                                 continue;
1818                         }
1819 
1820                         /* record local slen */
1821                         slen = fa->fa_slen;
1822                 }
1823 
1824                 /* update leaf slen */
1825                 n->slen = slen;
1826 
1827                 if (hlist_empty(&n->leaf)) {
1828                         put_child_root(pn, n->key, NULL);
1829                         node_free(n);
1830                 }
1831         }
1832 }
1833 
1834 /* Caller must hold RTNL. */
1835 int fib_table_flush(struct net *net, struct fib_table *tb)
1836 {
1837         struct trie *t = (struct trie *)tb->tb_data;
1838         struct key_vector *pn = t->kv;
1839         unsigned long cindex = 1;
1840         struct hlist_node *tmp;
1841         struct fib_alias *fa;
1842         int found = 0;
1843 
1844         /* walk trie in reverse order */
1845         for (;;) {
1846                 unsigned char slen = 0;
1847                 struct key_vector *n;
1848 
1849                 if (!(cindex--)) {
1850                         t_key pkey = pn->key;
1851 
1852                         /* cannot resize the trie vector */
1853                         if (IS_TRIE(pn))
1854                                 break;
1855 
1856                         /* update the suffix to address pulled leaves */
1857                         if (pn->slen > pn->pos)
1858                                 update_suffix(pn);
1859 
1860                         /* resize completed node */
1861                         pn = resize(t, pn);
1862                         cindex = get_index(pkey, pn);
1863 
1864                         continue;
1865                 }
1866 
1867                 /* grab the next available node */
1868                 n = get_child(pn, cindex);
1869                 if (!n)
1870                         continue;
1871 
1872                 if (IS_TNODE(n)) {
1873                         /* record pn and cindex for leaf walking */
1874                         pn = n;
1875                         cindex = 1ul << n->bits;
1876 
1877                         continue;
1878                 }
1879 
1880                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1881                         struct fib_info *fi = fa->fa_info;
1882 
1883                         if (!fi || !(fi->fib_flags & RTNH_F_DEAD) ||
1884                             tb->tb_id != fa->tb_id) {
1885                                 slen = fa->fa_slen;
1886                                 continue;
1887                         }
1888 
1889                         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
1890                                                  n->key,
1891                                                  KEYLENGTH - fa->fa_slen, fa,
1892                                                  NULL);
1893                         hlist_del_rcu(&fa->fa_list);
1894                         fib_release_info(fa->fa_info);
1895                         alias_free_mem_rcu(fa);
1896                         found++;
1897                 }
1898 
1899                 /* update leaf slen */
1900                 n->slen = slen;
1901 
1902                 if (hlist_empty(&n->leaf)) {
1903                         put_child_root(pn, n->key, NULL);
1904                         node_free(n);
1905                 }
1906         }
1907 
1908         pr_debug("trie_flush found=%d\n", found);
1909         return found;
1910 }
1911 
1912 static void fib_leaf_notify(struct net *net, struct key_vector *l,
1913                             struct fib_table *tb, struct notifier_block *nb)
1914 {
1915         struct fib_alias *fa;
1916 
1917         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1918                 struct fib_info *fi = fa->fa_info;
1919 
1920                 if (!fi)
1921                         continue;
1922 
1923                 /* local and main table can share the same trie,
1924                  * so don't notify twice for the same entry.
1925                  */
1926                 if (tb->tb_id != fa->tb_id)
1927                         continue;
1928 
1929                 call_fib_entry_notifier(nb, net, FIB_EVENT_ENTRY_ADD, l->key,
1930                                         KEYLENGTH - fa->fa_slen, fa);
1931         }
1932 }
1933 
1934 static void fib_table_notify(struct net *net, struct fib_table *tb,
1935                              struct notifier_block *nb)
1936 {
1937         struct trie *t = (struct trie *)tb->tb_data;
1938         struct key_vector *l, *tp = t->kv;
1939         t_key key = 0;
1940 
1941         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1942                 fib_leaf_notify(net, l, tb, nb);
1943 
1944                 key = l->key + 1;
1945                 /* stop in case of wrap around */
1946                 if (key < l->key)
1947                         break;
1948         }
1949 }
1950 
1951 void fib_notify(struct net *net, struct notifier_block *nb)
1952 {
1953         unsigned int h;
1954 
1955         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
1956                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
1957                 struct fib_table *tb;
1958 
1959                 hlist_for_each_entry_rcu(tb, head, tb_hlist)
1960                         fib_table_notify(net, tb, nb);
1961         }
1962 }
1963 
1964 static void __trie_free_rcu(struct rcu_head *head)
1965 {
1966         struct fib_table *tb = container_of(head, struct fib_table, rcu);
1967 #ifdef CONFIG_IP_FIB_TRIE_STATS
1968         struct trie *t = (struct trie *)tb->tb_data;
1969 
1970         if (tb->tb_data == tb->__data)
1971                 free_percpu(t->stats);
1972 #endif /* CONFIG_IP_FIB_TRIE_STATS */
1973         kfree(tb);
1974 }
1975 
1976 void fib_free_table(struct fib_table *tb)
1977 {
1978         call_rcu(&tb->rcu, __trie_free_rcu);
1979 }
1980 
1981 static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
1982                              struct sk_buff *skb, struct netlink_callback *cb)
1983 {
1984         __be32 xkey = htonl(l->key);
1985         struct fib_alias *fa;
1986         int i, s_i;
1987 
1988         s_i = cb->args[4];
1989         i = 0;
1990 
1991         /* rcu_read_lock is hold by caller */
1992         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1993                 int err;
1994 
1995                 if (i < s_i) {
1996                         i++;
1997                         continue;
1998                 }
1999 
2000                 if (tb->tb_id != fa->tb_id) {
2001                         i++;
2002                         continue;
2003                 }
2004 
2005                 err = fib_dump_info(skb, NETLINK_CB(cb->skb).portid,
2006                                     cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2007                                     tb->tb_id, fa->fa_type,
2008                                     xkey, KEYLENGTH - fa->fa_slen,
2009                                     fa->fa_tos, fa->fa_info, NLM_F_MULTI);
2010                 if (err < 0) {
2011                         cb->args[4] = i;
2012                         return err;
2013                 }
2014                 i++;
2015         }
2016 
2017         cb->args[4] = i;
2018         return skb->len;
2019 }
2020 
2021 /* rcu_read_lock needs to be hold by caller from readside */
2022 int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
2023                    struct netlink_callback *cb)
2024 {
2025         struct trie *t = (struct trie *)tb->tb_data;
2026         struct key_vector *l, *tp = t->kv;
2027         /* Dump starting at last key.
2028          * Note: 0.0.0.0/0 (ie default) is first key.
2029          */
2030         int count = cb->args[2];
2031         t_key key = cb->args[3];
2032 
2033         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
2034                 int err;
2035 
2036                 err = fn_trie_dump_leaf(l, tb, skb, cb);
2037                 if (err < 0) {
2038                         cb->args[3] = key;
2039                         cb->args[2] = count;
2040                         return err;
2041                 }
2042 
2043                 ++count;
2044                 key = l->key + 1;
2045 
2046                 memset(&cb->args[4], 0,
2047                        sizeof(cb->args) - 4*sizeof(cb->args[0]));
2048 
2049                 /* stop loop if key wrapped back to 0 */
2050                 if (key < l->key)
2051                         break;
2052         }
2053 
2054         cb->args[3] = key;
2055         cb->args[2] = count;
2056 
2057         return skb->len;
2058 }
2059 
2060 void __init fib_trie_init(void)
2061 {
2062         fn_alias_kmem = kmem_cache_create("ip_fib_alias",
2063                                           sizeof(struct fib_alias),
2064                                           0, SLAB_PANIC, NULL);
2065 
2066         trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
2067                                            LEAF_SIZE,
2068                                            0, SLAB_PANIC, NULL);
2069 }
2070 
2071 struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
2072 {
2073         struct fib_table *tb;
2074         struct trie *t;
2075         size_t sz = sizeof(*tb);
2076 
2077         if (!alias)
2078                 sz += sizeof(struct trie);
2079 
2080         tb = kzalloc(sz, GFP_KERNEL);
2081         if (!tb)
2082                 return NULL;
2083 
2084         tb->tb_id = id;
2085         tb->tb_num_default = 0;
2086         tb->tb_data = (alias ? alias->__data : tb->__data);
2087 
2088         if (alias)
2089                 return tb;
2090 
2091         t = (struct trie *) tb->tb_data;
2092         t->kv[0].pos = KEYLENGTH;
2093         t->kv[0].slen = KEYLENGTH;
2094 #ifdef CONFIG_IP_FIB_TRIE_STATS
2095         t->stats = alloc_percpu(struct trie_use_stats);
2096         if (!t->stats) {
2097                 kfree(tb);
2098                 tb = NULL;
2099         }
2100 #endif
2101 
2102         return tb;
2103 }
2104 
2105 #ifdef CONFIG_PROC_FS
2106 /* Depth first Trie walk iterator */
2107 struct fib_trie_iter {
2108         struct seq_net_private p;
2109         struct fib_table *tb;
2110         struct key_vector *tnode;
2111         unsigned int index;
2112         unsigned int depth;
2113 };
2114 
2115 static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
2116 {
2117         unsigned long cindex = iter->index;
2118         struct key_vector *pn = iter->tnode;
2119         t_key pkey;
2120 
2121         pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
2122                  iter->tnode, iter->index, iter->depth);
2123 
2124         while (!IS_TRIE(pn)) {
2125                 while (cindex < child_length(pn)) {
2126                         struct key_vector *n = get_child_rcu(pn, cindex++);
2127 
2128                         if (!n)
2129                                 continue;
2130 
2131                         if (IS_LEAF(n)) {
2132                                 iter->tnode = pn;
2133                                 iter->index = cindex;
2134                         } else {
2135                                 /* push down one level */
2136                                 iter->tnode = n;
2137                                 iter->index = 0;
2138                                 ++iter->depth;
2139                         }
2140 
2141                         return n;
2142                 }
2143 
2144                 /* Current node exhausted, pop back up */
2145                 pkey = pn->key;
2146                 pn = node_parent_rcu(pn);
2147                 cindex = get_index(pkey, pn) + 1;
2148                 --iter->depth;
2149         }
2150 
2151         /* record root node so further searches know we are done */
2152         iter->tnode = pn;
2153         iter->index = 0;
2154 
2155         return NULL;
2156 }
2157 
2158 static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
2159                                              struct trie *t)
2160 {
2161         struct key_vector *n, *pn;
2162 
2163         if (!t)
2164                 return NULL;
2165 
2166         pn = t->kv;
2167         n = rcu_dereference(pn->tnode[0]);
2168         if (!n)
2169                 return NULL;
2170 
2171         if (IS_TNODE(n)) {
2172                 iter->tnode = n;
2173                 iter->index = 0;
2174                 iter->depth = 1;
2175         } else {
2176                 iter->tnode = pn;
2177                 iter->index = 0;
2178                 iter->depth = 0;
2179         }
2180 
2181         return n;
2182 }
2183 
2184 static void trie_collect_stats(struct trie *t, struct trie_stat *s)
2185 {
2186         struct key_vector *n;
2187         struct fib_trie_iter iter;
2188 
2189         memset(s, 0, sizeof(*s));
2190 
2191         rcu_read_lock();
2192         for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
2193                 if (IS_LEAF(n)) {
2194                         struct fib_alias *fa;
2195 
2196                         s->leaves++;
2197                         s->totdepth += iter.depth;
2198                         if (iter.depth > s->maxdepth)
2199                                 s->maxdepth = iter.depth;
2200 
2201                         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list)
2202                                 ++s->prefixes;
2203                 } else {
2204                         s->tnodes++;
2205                         if (n->bits < MAX_STAT_DEPTH)
2206                                 s->nodesizes[n->bits]++;
2207                         s->nullpointers += tn_info(n)->empty_children;
2208                 }
2209         }
2210         rcu_read_unlock();
2211 }
2212 
2213 /*
2214  *      This outputs /proc/net/fib_triestats
2215  */
2216 static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
2217 {
2218         unsigned int i, max, pointers, bytes, avdepth;
2219 
2220         if (stat->leaves)
2221                 avdepth = stat->totdepth*100 / stat->leaves;
2222         else
2223                 avdepth = 0;
2224 
2225         seq_printf(seq, "\tAver depth:     %u.%02d\n",
2226                    avdepth / 100, avdepth % 100);
2227         seq_printf(seq, "\tMax depth:      %u\n", stat->maxdepth);
2228 
2229         seq_printf(seq, "\tLeaves:         %u\n", stat->leaves);
2230         bytes = LEAF_SIZE * stat->leaves;
2231 
2232         seq_printf(seq, "\tPrefixes:       %u\n", stat->prefixes);
2233         bytes += sizeof(struct fib_alias) * stat->prefixes;
2234 
2235         seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
2236         bytes += TNODE_SIZE(0) * stat->tnodes;
2237 
2238         max = MAX_STAT_DEPTH;
2239         while (max > 0 && stat->nodesizes[max-1] == 0)
2240                 max--;
2241 
2242         pointers = 0;
2243         for (i = 1; i < max; i++)
2244                 if (stat->nodesizes[i] != 0) {
2245                         seq_printf(seq, "  %u: %u",  i, stat->nodesizes[i]);
2246                         pointers += (1<<i) * stat->nodesizes[i];
2247                 }
2248         seq_putc(seq, '\n');
2249         seq_printf(seq, "\tPointers: %u\n", pointers);
2250 
2251         bytes += sizeof(struct key_vector *) * pointers;
2252         seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
2253         seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
2254 }
2255 
2256 #ifdef CONFIG_IP_FIB_TRIE_STATS
2257 static void trie_show_usage(struct seq_file *seq,
2258                             const struct trie_use_stats __percpu *stats)
2259 {
2260         struct trie_use_stats s = { 0 };
2261         int cpu;
2262 
2263         /* loop through all of the CPUs and gather up the stats */
2264         for_each_possible_cpu(cpu) {
2265                 const struct trie_use_stats *pcpu = per_cpu_ptr(stats, cpu);
2266 
2267                 s.gets += pcpu->gets;
2268                 s.backtrack += pcpu->backtrack;
2269                 s.semantic_match_passed += pcpu->semantic_match_passed;
2270                 s.semantic_match_miss += pcpu->semantic_match_miss;
2271                 s.null_node_hit += pcpu->null_node_hit;
2272                 s.resize_node_skipped += pcpu->resize_node_skipped;
2273         }
2274 
2275         seq_printf(seq, "\nCounters:\n---------\n");
2276         seq_printf(seq, "gets = %u\n", s.gets);
2277         seq_printf(seq, "backtracks = %u\n", s.backtrack);
2278         seq_printf(seq, "semantic match passed = %u\n",
2279                    s.semantic_match_passed);
2280         seq_printf(seq, "semantic match miss = %u\n", s.semantic_match_miss);
2281         seq_printf(seq, "null node hit= %u\n", s.null_node_hit);
2282         seq_printf(seq, "skipped node resize = %u\n\n", s.resize_node_skipped);
2283 }
2284 #endif /*  CONFIG_IP_FIB_TRIE_STATS */
2285 
2286 static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
2287 {
2288         if (tb->tb_id == RT_TABLE_LOCAL)
2289                 seq_puts(seq, "Local:\n");
2290         else if (tb->tb_id == RT_TABLE_MAIN)
2291                 seq_puts(seq, "Main:\n");
2292         else
2293                 seq_printf(seq, "Id %d:\n", tb->tb_id);
2294 }
2295 
2296 
2297 static int fib_triestat_seq_show(struct seq_file *seq, void *v)
2298 {
2299         struct net *net = (struct net *)seq->private;
2300         unsigned int h;
2301 
2302         seq_printf(seq,
2303                    "Basic info: size of leaf:"
2304                    " %zd bytes, size of tnode: %zd bytes.\n",
2305                    LEAF_SIZE, TNODE_SIZE(0));
2306 
2307         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2308                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2309                 struct fib_table *tb;
2310 
2311                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2312                         struct trie *t = (struct trie *) tb->tb_data;
2313                         struct trie_stat stat;
2314 
2315                         if (!t)
2316                                 continue;
2317 
2318                         fib_table_print(seq, tb);
2319 
2320                         trie_collect_stats(t, &stat);
2321                         trie_show_stats(seq, &stat);
2322 #ifdef CONFIG_IP_FIB_TRIE_STATS
2323                         trie_show_usage(seq, t->stats);
2324 #endif
2325                 }
2326         }
2327 
2328         return 0;
2329 }
2330 
2331 static int fib_triestat_seq_open(struct inode *inode, struct file *file)
2332 {
2333         return single_open_net(inode, file, fib_triestat_seq_show);
2334 }
2335 
2336 static const struct file_operations fib_triestat_fops = {
2337         .owner  = THIS_MODULE,
2338         .open   = fib_triestat_seq_open,
2339         .read   = seq_read,
2340         .llseek = seq_lseek,
2341         .release = single_release_net,
2342 };
2343 
2344 static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
2345 {
2346         struct fib_trie_iter *iter = seq->private;
2347         struct net *net = seq_file_net(seq);
2348         loff_t idx = 0;
2349         unsigned int h;
2350 
2351         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2352                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2353                 struct fib_table *tb;
2354 
2355                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2356                         struct key_vector *n;
2357 
2358                         for (n = fib_trie_get_first(iter,
2359                                                     (struct trie *) tb->tb_data);
2360                              n; n = fib_trie_get_next(iter))
2361                                 if (pos == idx++) {
2362                                         iter->tb = tb;
2363                                         return n;
2364                                 }
2365                 }
2366         }
2367 
2368         return NULL;
2369 }
2370 
2371 static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
2372         __acquires(RCU)
2373 {
2374         rcu_read_lock();
2375         return fib_trie_get_idx(seq, *pos);
2376 }
2377 
2378 static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2379 {
2380         struct fib_trie_iter *iter = seq->private;
2381         struct net *net = seq_file_net(seq);
2382         struct fib_table *tb = iter->tb;
2383         struct hlist_node *tb_node;
2384         unsigned int h;
2385         struct key_vector *n;
2386 
2387         ++*pos;
2388         /* next node in same table */
2389         n = fib_trie_get_next(iter);
2390         if (n)
2391                 return n;
2392 
2393         /* walk rest of this hash chain */
2394         h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
2395         while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
2396                 tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
2397                 n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2398                 if (n)
2399                         goto found;
2400         }
2401 
2402         /* new hash chain */
2403         while (++h < FIB_TABLE_HASHSZ) {
2404                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2405                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2406                         n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2407                         if (n)
2408                                 goto found;
2409                 }
2410         }
2411         return NULL;
2412 
2413 found:
2414         iter->tb = tb;
2415         return n;
2416 }
2417 
2418 static void fib_trie_seq_stop(struct seq_file *seq, void *v)
2419         __releases(RCU)
2420 {
2421         rcu_read_unlock();
2422 }
2423 
2424 static void seq_indent(struct seq_file *seq, int n)
2425 {
2426         while (n-- > 0)
2427                 seq_puts(seq, "   ");
2428 }
2429 
2430 static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
2431 {
2432         switch (s) {
2433         case RT_SCOPE_UNIVERSE: return "universe";
2434         case RT_SCOPE_SITE:     return "site";
2435         case RT_SCOPE_LINK:     return "link";
2436         case RT_SCOPE_HOST:     return "host";
2437         case RT_SCOPE_NOWHERE:  return "nowhere";
2438         default:
2439                 snprintf(buf, len, "scope=%d", s);
2440                 return buf;
2441         }
2442 }
2443 
2444 static const char *const rtn_type_names[__RTN_MAX] = {
2445         [RTN_UNSPEC] = "UNSPEC",
2446         [RTN_UNICAST] = "UNICAST",
2447         [RTN_LOCAL] = "LOCAL",
2448         [RTN_BROADCAST] = "BROADCAST",
2449         [RTN_ANYCAST] = "ANYCAST",
2450         [RTN_MULTICAST] = "MULTICAST",
2451         [RTN_BLACKHOLE] = "BLACKHOLE",
2452         [RTN_UNREACHABLE] = "UNREACHABLE",
2453         [RTN_PROHIBIT] = "PROHIBIT",
2454         [RTN_THROW] = "THROW",
2455         [RTN_NAT] = "NAT",
2456         [RTN_XRESOLVE] = "XRESOLVE",
2457 };
2458 
2459 static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
2460 {
2461         if (t < __RTN_MAX && rtn_type_names[t])
2462                 return rtn_type_names[t];
2463         snprintf(buf, len, "type %u", t);
2464         return buf;
2465 }
2466 
2467 /* Pretty print the trie */
2468 static int fib_trie_seq_show(struct seq_file *seq, void *v)
2469 {
2470         const struct fib_trie_iter *iter = seq->private;
2471         struct key_vector *n = v;
2472 
2473         if (IS_TRIE(node_parent_rcu(n)))
2474                 fib_table_print(seq, iter->tb);
2475 
2476         if (IS_TNODE(n)) {
2477                 __be32 prf = htonl(n->key);
2478 
2479                 seq_indent(seq, iter->depth-1);
2480                 seq_printf(seq, "  +-- %pI4/%zu %u %u %u\n",
2481                            &prf, KEYLENGTH - n->pos - n->bits, n->bits,
2482                            tn_info(n)->full_children,
2483                            tn_info(n)->empty_children);
2484         } else {
2485                 __be32 val = htonl(n->key);
2486                 struct fib_alias *fa;
2487 
2488                 seq_indent(seq, iter->depth);
2489                 seq_printf(seq, "  |-- %pI4\n", &val);
2490 
2491                 hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
2492                         char buf1[32], buf2[32];
2493 
2494                         seq_indent(seq, iter->depth + 1);
2495                         seq_printf(seq, "  /%zu %s %s",
2496                                    KEYLENGTH - fa->fa_slen,
2497                                    rtn_scope(buf1, sizeof(buf1),
2498                                              fa->fa_info->fib_scope),
2499                                    rtn_type(buf2, sizeof(buf2),
2500                                             fa->fa_type));
2501                         if (fa->fa_tos)
2502                                 seq_printf(seq, " tos=%d", fa->fa_tos);
2503                         seq_putc(seq, '\n');
2504                 }
2505         }
2506 
2507         return 0;
2508 }
2509 
2510 static const struct seq_operations fib_trie_seq_ops = {
2511         .start  = fib_trie_seq_start,
2512         .next   = fib_trie_seq_next,
2513         .stop   = fib_trie_seq_stop,
2514         .show   = fib_trie_seq_show,
2515 };
2516 
2517 static int fib_trie_seq_open(struct inode *inode, struct file *file)
2518 {
2519         return seq_open_net(inode, file, &fib_trie_seq_ops,
2520                             sizeof(struct fib_trie_iter));
2521 }
2522 
2523 static const struct file_operations fib_trie_fops = {
2524         .owner  = THIS_MODULE,
2525         .open   = fib_trie_seq_open,
2526         .read   = seq_read,
2527         .llseek = seq_lseek,
2528         .release = seq_release_net,
2529 };
2530 
2531 struct fib_route_iter {
2532         struct seq_net_private p;
2533         struct fib_table *main_tb;
2534         struct key_vector *tnode;
2535         loff_t  pos;
2536         t_key   key;
2537 };
2538 
2539 static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
2540                                             loff_t pos)
2541 {
2542         struct key_vector *l, **tp = &iter->tnode;
2543         t_key key;
2544 
2545         /* use cached location of previously found key */
2546         if (iter->pos > 0 && pos >= iter->pos) {
2547                 key = iter->key;
2548         } else {
2549                 iter->pos = 1;
2550                 key = 0;
2551         }
2552 
2553         pos -= iter->pos;
2554 
2555         while ((l = leaf_walk_rcu(tp, key)) && (pos-- > 0)) {
2556                 key = l->key + 1;
2557                 iter->pos++;
2558                 l = NULL;
2559 
2560                 /* handle unlikely case of a key wrap */
2561                 if (!key)
2562                         break;
2563         }
2564 
2565         if (l)
2566                 iter->key = l->key;     /* remember it */
2567         else
2568                 iter->pos = 0;          /* forget it */
2569 
2570         return l;
2571 }
2572 
2573 static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
2574         __acquires(RCU)
2575 {
2576         struct fib_route_iter *iter = seq->private;
2577         struct fib_table *tb;
2578         struct trie *t;
2579 
2580         rcu_read_lock();
2581 
2582         tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
2583         if (!tb)
2584                 return NULL;
2585 
2586         iter->main_tb = tb;
2587         t = (struct trie *)tb->tb_data;
2588         iter->tnode = t->kv;
2589 
2590         if (*pos != 0)
2591                 return fib_route_get_idx(iter, *pos);
2592 
2593         iter->pos = 0;
2594         iter->key = KEY_MAX;
2595 
2596         return SEQ_START_TOKEN;
2597 }
2598 
2599 static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2600 {
2601         struct fib_route_iter *iter = seq->private;
2602         struct key_vector *l = NULL;
2603         t_key key = iter->key + 1;
2604 
2605         ++*pos;
2606 
2607         /* only allow key of 0 for start of sequence */
2608         if ((v == SEQ_START_TOKEN) || key)
2609                 l = leaf_walk_rcu(&iter->tnode, key);
2610 
2611         if (l) {
2612                 iter->key = l->key;
2613                 iter->pos++;
2614         } else {
2615                 iter->pos = 0;
2616         }
2617 
2618         return l;
2619 }
2620 
2621 static void fib_route_seq_stop(struct seq_file *seq, void *v)
2622         __releases(RCU)
2623 {
2624         rcu_read_unlock();
2625 }
2626 
2627 static unsigned int fib_flag_trans(int type, __be32 mask, const struct fib_info *fi)
2628 {
2629         unsigned int flags = 0;
2630 
2631         if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
2632                 flags = RTF_REJECT;
2633         if (fi && fi->fib_nh->nh_gw)
2634                 flags |= RTF_GATEWAY;
2635         if (mask == htonl(0xFFFFFFFF))
2636                 flags |= RTF_HOST;
2637         flags |= RTF_UP;
2638         return flags;
2639 }
2640 
2641 /*
2642  *      This outputs /proc/net/route.
2643  *      The format of the file is not supposed to be changed
2644  *      and needs to be same as fib_hash output to avoid breaking
2645  *      legacy utilities
2646  */
2647 static int fib_route_seq_show(struct seq_file *seq, void *v)
2648 {
2649         struct fib_route_iter *iter = seq->private;
2650         struct fib_table *tb = iter->main_tb;
2651         struct fib_alias *fa;
2652         struct key_vector *l = v;
2653         __be32 prefix;
2654 
2655         if (v == SEQ_START_TOKEN) {
2656                 seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
2657                            "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
2658                            "\tWindow\tIRTT");
2659                 return 0;
2660         }
2661 
2662         prefix = htonl(l->key);
2663 
2664         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2665                 const struct fib_info *fi = fa->fa_info;
2666                 __be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
2667                 unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
2668 
2669                 if ((fa->fa_type == RTN_BROADCAST) ||
2670                     (fa->fa_type == RTN_MULTICAST))
2671                         continue;
2672 
2673                 if (fa->tb_id != tb->tb_id)
2674                         continue;
2675 
2676                 seq_setwidth(seq, 127);
2677 
2678                 if (fi)
2679                         seq_printf(seq,
2680                                    "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
2681                                    "%d\t%08X\t%d\t%u\t%u",
2682                                    fi->fib_dev ? fi->fib_dev->name : "*",
2683                                    prefix,
2684                                    fi->fib_nh->nh_gw, flags, 0, 0,
2685                                    fi->fib_priority,
2686                                    mask,
2687                                    (fi->fib_advmss ?
2688                                     fi->fib_advmss + 40 : 0),
2689                                    fi->fib_window,
2690                                    fi->fib_rtt >> 3);
2691                 else
2692                         seq_printf(seq,
2693                                    "*\t%08X\t%08X\t%04X\t%d\t%u\t"
2694                                    "%d\t%08X\t%d\t%u\t%u",
2695                                    prefix, 0, flags, 0, 0, 0,
2696                                    mask, 0, 0, 0);
2697 
2698                 seq_pad(seq, '\n');
2699         }
2700 
2701         return 0;
2702 }
2703 
2704 static const struct seq_operations fib_route_seq_ops = {
2705         .start  = fib_route_seq_start,
2706         .next   = fib_route_seq_next,
2707         .stop   = fib_route_seq_stop,
2708         .show   = fib_route_seq_show,
2709 };
2710 
2711 static int fib_route_seq_open(struct inode *inode, struct file *file)
2712 {
2713         return seq_open_net(inode, file, &fib_route_seq_ops,
2714                             sizeof(struct fib_route_iter));
2715 }
2716 
2717 static const struct file_operations fib_route_fops = {
2718         .owner  = THIS_MODULE,
2719         .open   = fib_route_seq_open,
2720         .read   = seq_read,
2721         .llseek = seq_lseek,
2722         .release = seq_release_net,
2723 };
2724 
2725 int __net_init fib_proc_init(struct net *net)
2726 {
2727         if (!proc_create("fib_trie", S_IRUGO, net->proc_net, &fib_trie_fops))
2728                 goto out1;
2729 
2730         if (!proc_create("fib_triestat", S_IRUGO, net->proc_net,
2731                          &fib_triestat_fops))
2732                 goto out2;
2733 
2734         if (!proc_create("route", S_IRUGO, net->proc_net, &fib_route_fops))
2735                 goto out3;
2736 
2737         return 0;
2738 
2739 out3:
2740         remove_proc_entry("fib_triestat", net->proc_net);
2741 out2:
2742         remove_proc_entry("fib_trie", net->proc_net);
2743 out1:
2744         return -ENOMEM;
2745 }
2746 
2747 void __net_exit fib_proc_exit(struct net *net)
2748 {
2749         remove_proc_entry("fib_trie", net->proc_net);
2750         remove_proc_entry("fib_triestat", net->proc_net);
2751         remove_proc_entry("route", net->proc_net);
2752 }
2753 
2754 #endif /* CONFIG_PROC_FS */
2755 

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