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Linux/net/ipv4/fib_trie.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  *
  4  *   Robert Olsson <robert.olsson@its.uu.se> Uppsala Universitet
  5  *     & Swedish University of Agricultural Sciences.
  6  *
  7  *   Jens Laas <jens.laas@data.slu.se> Swedish University of
  8  *     Agricultural Sciences.
  9  *
 10  *   Hans Liss <hans.liss@its.uu.se>  Uppsala Universitet
 11  *
 12  * This work is based on the LPC-trie which is originally described in:
 13  *
 14  * An experimental study of compression methods for dynamic tries
 15  * Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
 16  * http://www.csc.kth.se/~snilsson/software/dyntrie2/
 17  *
 18  * IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
 19  * IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
 20  *
 21  * Code from fib_hash has been reused which includes the following header:
 22  *
 23  * INET         An implementation of the TCP/IP protocol suite for the LINUX
 24  *              operating system.  INET is implemented using the  BSD Socket
 25  *              interface as the means of communication with the user level.
 26  *
 27  *              IPv4 FIB: lookup engine and maintenance routines.
 28  *
 29  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 30  *
 31  * Substantial contributions to this work comes from:
 32  *
 33  *              David S. Miller, <davem@davemloft.net>
 34  *              Stephen Hemminger <shemminger@osdl.org>
 35  *              Paul E. McKenney <paulmck@us.ibm.com>
 36  *              Patrick McHardy <kaber@trash.net>
 37  */
 38 
 39 #define VERSION "0.409"
 40 
 41 #include <linux/cache.h>
 42 #include <linux/uaccess.h>
 43 #include <linux/bitops.h>
 44 #include <linux/types.h>
 45 #include <linux/kernel.h>
 46 #include <linux/mm.h>
 47 #include <linux/string.h>
 48 #include <linux/socket.h>
 49 #include <linux/sockios.h>
 50 #include <linux/errno.h>
 51 #include <linux/in.h>
 52 #include <linux/inet.h>
 53 #include <linux/inetdevice.h>
 54 #include <linux/netdevice.h>
 55 #include <linux/if_arp.h>
 56 #include <linux/proc_fs.h>
 57 #include <linux/rcupdate.h>
 58 #include <linux/skbuff.h>
 59 #include <linux/netlink.h>
 60 #include <linux/init.h>
 61 #include <linux/list.h>
 62 #include <linux/slab.h>
 63 #include <linux/export.h>
 64 #include <linux/vmalloc.h>
 65 #include <linux/notifier.h>
 66 #include <net/net_namespace.h>
 67 #include <net/ip.h>
 68 #include <net/protocol.h>
 69 #include <net/route.h>
 70 #include <net/tcp.h>
 71 #include <net/sock.h>
 72 #include <net/ip_fib.h>
 73 #include <net/fib_notifier.h>
 74 #include <trace/events/fib.h>
 75 #include "fib_lookup.h"
 76 
 77 static int call_fib_entry_notifier(struct notifier_block *nb, struct net *net,
 78                                    enum fib_event_type event_type, u32 dst,
 79                                    int dst_len, struct fib_alias *fa)
 80 {
 81         struct fib_entry_notifier_info info = {
 82                 .dst = dst,
 83                 .dst_len = dst_len,
 84                 .fi = fa->fa_info,
 85                 .tos = fa->fa_tos,
 86                 .type = fa->fa_type,
 87                 .tb_id = fa->tb_id,
 88         };
 89         return call_fib4_notifier(nb, net, event_type, &info.info);
 90 }
 91 
 92 static int call_fib_entry_notifiers(struct net *net,
 93                                     enum fib_event_type event_type, u32 dst,
 94                                     int dst_len, struct fib_alias *fa,
 95                                     struct netlink_ext_ack *extack)
 96 {
 97         struct fib_entry_notifier_info info = {
 98                 .info.extack = extack,
 99                 .dst = dst,
100                 .dst_len = dst_len,
101                 .fi = fa->fa_info,
102                 .tos = fa->fa_tos,
103                 .type = fa->fa_type,
104                 .tb_id = fa->tb_id,
105         };
106         return call_fib4_notifiers(net, event_type, &info.info);
107 }
108 
109 #define MAX_STAT_DEPTH 32
110 
111 #define KEYLENGTH       (8*sizeof(t_key))
112 #define KEY_MAX         ((t_key)~0)
113 
114 typedef unsigned int t_key;
115 
116 #define IS_TRIE(n)      ((n)->pos >= KEYLENGTH)
117 #define IS_TNODE(n)     ((n)->bits)
118 #define IS_LEAF(n)      (!(n)->bits)
119 
120 struct key_vector {
121         t_key key;
122         unsigned char pos;              /* 2log(KEYLENGTH) bits needed */
123         unsigned char bits;             /* 2log(KEYLENGTH) bits needed */
124         unsigned char slen;
125         union {
126                 /* This list pointer if valid if (pos | bits) == 0 (LEAF) */
127                 struct hlist_head leaf;
128                 /* This array is valid if (pos | bits) > 0 (TNODE) */
129                 struct key_vector __rcu *tnode[0];
130         };
131 };
132 
133 struct tnode {
134         struct rcu_head rcu;
135         t_key empty_children;           /* KEYLENGTH bits needed */
136         t_key full_children;            /* KEYLENGTH bits needed */
137         struct key_vector __rcu *parent;
138         struct key_vector kv[1];
139 #define tn_bits kv[0].bits
140 };
141 
142 #define TNODE_SIZE(n)   offsetof(struct tnode, kv[0].tnode[n])
143 #define LEAF_SIZE       TNODE_SIZE(1)
144 
145 #ifdef CONFIG_IP_FIB_TRIE_STATS
146 struct trie_use_stats {
147         unsigned int gets;
148         unsigned int backtrack;
149         unsigned int semantic_match_passed;
150         unsigned int semantic_match_miss;
151         unsigned int null_node_hit;
152         unsigned int resize_node_skipped;
153 };
154 #endif
155 
156 struct trie_stat {
157         unsigned int totdepth;
158         unsigned int maxdepth;
159         unsigned int tnodes;
160         unsigned int leaves;
161         unsigned int nullpointers;
162         unsigned int prefixes;
163         unsigned int nodesizes[MAX_STAT_DEPTH];
164 };
165 
166 struct trie {
167         struct key_vector kv[1];
168 #ifdef CONFIG_IP_FIB_TRIE_STATS
169         struct trie_use_stats __percpu *stats;
170 #endif
171 };
172 
173 static struct key_vector *resize(struct trie *t, struct key_vector *tn);
174 static unsigned int tnode_free_size;
175 
176 /*
177  * synchronize_rcu after call_rcu for outstanding dirty memory; it should be
178  * especially useful before resizing the root node with PREEMPT_NONE configs;
179  * the value was obtained experimentally, aiming to avoid visible slowdown.
180  */
181 unsigned int sysctl_fib_sync_mem = 512 * 1024;
182 unsigned int sysctl_fib_sync_mem_min = 64 * 1024;
183 unsigned int sysctl_fib_sync_mem_max = 64 * 1024 * 1024;
184 
185 static struct kmem_cache *fn_alias_kmem __ro_after_init;
186 static struct kmem_cache *trie_leaf_kmem __ro_after_init;
187 
188 static inline struct tnode *tn_info(struct key_vector *kv)
189 {
190         return container_of(kv, struct tnode, kv[0]);
191 }
192 
193 /* caller must hold RTNL */
194 #define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
195 #define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
196 
197 /* caller must hold RCU read lock or RTNL */
198 #define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
199 #define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
200 
201 /* wrapper for rcu_assign_pointer */
202 static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
203 {
204         if (n)
205                 rcu_assign_pointer(tn_info(n)->parent, tp);
206 }
207 
208 #define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(n)->parent, p)
209 
210 /* This provides us with the number of children in this node, in the case of a
211  * leaf this will return 0 meaning none of the children are accessible.
212  */
213 static inline unsigned long child_length(const struct key_vector *tn)
214 {
215         return (1ul << tn->bits) & ~(1ul);
216 }
217 
218 #define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
219 
220 static inline unsigned long get_index(t_key key, struct key_vector *kv)
221 {
222         unsigned long index = key ^ kv->key;
223 
224         if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
225                 return 0;
226 
227         return index >> kv->pos;
228 }
229 
230 /* To understand this stuff, an understanding of keys and all their bits is
231  * necessary. Every node in the trie has a key associated with it, but not
232  * all of the bits in that key are significant.
233  *
234  * Consider a node 'n' and its parent 'tp'.
235  *
236  * If n is a leaf, every bit in its key is significant. Its presence is
237  * necessitated by path compression, since during a tree traversal (when
238  * searching for a leaf - unless we are doing an insertion) we will completely
239  * ignore all skipped bits we encounter. Thus we need to verify, at the end of
240  * a potentially successful search, that we have indeed been walking the
241  * correct key path.
242  *
243  * Note that we can never "miss" the correct key in the tree if present by
244  * following the wrong path. Path compression ensures that segments of the key
245  * that are the same for all keys with a given prefix are skipped, but the
246  * skipped part *is* identical for each node in the subtrie below the skipped
247  * bit! trie_insert() in this implementation takes care of that.
248  *
249  * if n is an internal node - a 'tnode' here, the various parts of its key
250  * have many different meanings.
251  *
252  * Example:
253  * _________________________________________________________________
254  * | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
255  * -----------------------------------------------------------------
256  *  31  30  29  28  27  26  25  24  23  22  21  20  19  18  17  16
257  *
258  * _________________________________________________________________
259  * | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
260  * -----------------------------------------------------------------
261  *  15  14  13  12  11  10   9   8   7   6   5   4   3   2   1   0
262  *
263  * tp->pos = 22
264  * tp->bits = 3
265  * n->pos = 13
266  * n->bits = 4
267  *
268  * First, let's just ignore the bits that come before the parent tp, that is
269  * the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
270  * point we do not use them for anything.
271  *
272  * The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
273  * index into the parent's child array. That is, they will be used to find
274  * 'n' among tp's children.
275  *
276  * The bits from (n->pos + n->bits) to (tp->pos - 1) - "S" - are skipped bits
277  * for the node n.
278  *
279  * All the bits we have seen so far are significant to the node n. The rest
280  * of the bits are really not needed or indeed known in n->key.
281  *
282  * The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
283  * n's child array, and will of course be different for each child.
284  *
285  * The rest of the bits, from 0 to (n->pos -1) - "u" - are completely unknown
286  * at this point.
287  */
288 
289 static const int halve_threshold = 25;
290 static const int inflate_threshold = 50;
291 static const int halve_threshold_root = 15;
292 static const int inflate_threshold_root = 30;
293 
294 static void __alias_free_mem(struct rcu_head *head)
295 {
296         struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
297         kmem_cache_free(fn_alias_kmem, fa);
298 }
299 
300 static inline void alias_free_mem_rcu(struct fib_alias *fa)
301 {
302         call_rcu(&fa->rcu, __alias_free_mem);
303 }
304 
305 #define TNODE_KMALLOC_MAX \
306         ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct key_vector *))
307 #define TNODE_VMALLOC_MAX \
308         ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
309 
310 static void __node_free_rcu(struct rcu_head *head)
311 {
312         struct tnode *n = container_of(head, struct tnode, rcu);
313 
314         if (!n->tn_bits)
315                 kmem_cache_free(trie_leaf_kmem, n);
316         else
317                 kvfree(n);
318 }
319 
320 #define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
321 
322 static struct tnode *tnode_alloc(int bits)
323 {
324         size_t size;
325 
326         /* verify bits is within bounds */
327         if (bits > TNODE_VMALLOC_MAX)
328                 return NULL;
329 
330         /* determine size and verify it is non-zero and didn't overflow */
331         size = TNODE_SIZE(1ul << bits);
332 
333         if (size <= PAGE_SIZE)
334                 return kzalloc(size, GFP_KERNEL);
335         else
336                 return vzalloc(size);
337 }
338 
339 static inline void empty_child_inc(struct key_vector *n)
340 {
341         ++tn_info(n)->empty_children ? : ++tn_info(n)->full_children;
342 }
343 
344 static inline void empty_child_dec(struct key_vector *n)
345 {
346         tn_info(n)->empty_children-- ? : tn_info(n)->full_children--;
347 }
348 
349 static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
350 {
351         struct key_vector *l;
352         struct tnode *kv;
353 
354         kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
355         if (!kv)
356                 return NULL;
357 
358         /* initialize key vector */
359         l = kv->kv;
360         l->key = key;
361         l->pos = 0;
362         l->bits = 0;
363         l->slen = fa->fa_slen;
364 
365         /* link leaf to fib alias */
366         INIT_HLIST_HEAD(&l->leaf);
367         hlist_add_head(&fa->fa_list, &l->leaf);
368 
369         return l;
370 }
371 
372 static struct key_vector *tnode_new(t_key key, int pos, int bits)
373 {
374         unsigned int shift = pos + bits;
375         struct key_vector *tn;
376         struct tnode *tnode;
377 
378         /* verify bits and pos their msb bits clear and values are valid */
379         BUG_ON(!bits || (shift > KEYLENGTH));
380 
381         tnode = tnode_alloc(bits);
382         if (!tnode)
383                 return NULL;
384 
385         pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
386                  sizeof(struct key_vector *) << bits);
387 
388         if (bits == KEYLENGTH)
389                 tnode->full_children = 1;
390         else
391                 tnode->empty_children = 1ul << bits;
392 
393         tn = tnode->kv;
394         tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
395         tn->pos = pos;
396         tn->bits = bits;
397         tn->slen = pos;
398 
399         return tn;
400 }
401 
402 /* Check whether a tnode 'n' is "full", i.e. it is an internal node
403  * and no bits are skipped. See discussion in dyntree paper p. 6
404  */
405 static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
406 {
407         return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
408 }
409 
410 /* Add a child at position i overwriting the old value.
411  * Update the value of full_children and empty_children.
412  */
413 static void put_child(struct key_vector *tn, unsigned long i,
414                       struct key_vector *n)
415 {
416         struct key_vector *chi = get_child(tn, i);
417         int isfull, wasfull;
418 
419         BUG_ON(i >= child_length(tn));
420 
421         /* update emptyChildren, overflow into fullChildren */
422         if (!n && chi)
423                 empty_child_inc(tn);
424         if (n && !chi)
425                 empty_child_dec(tn);
426 
427         /* update fullChildren */
428         wasfull = tnode_full(tn, chi);
429         isfull = tnode_full(tn, n);
430 
431         if (wasfull && !isfull)
432                 tn_info(tn)->full_children--;
433         else if (!wasfull && isfull)
434                 tn_info(tn)->full_children++;
435 
436         if (n && (tn->slen < n->slen))
437                 tn->slen = n->slen;
438 
439         rcu_assign_pointer(tn->tnode[i], n);
440 }
441 
442 static void update_children(struct key_vector *tn)
443 {
444         unsigned long i;
445 
446         /* update all of the child parent pointers */
447         for (i = child_length(tn); i;) {
448                 struct key_vector *inode = get_child(tn, --i);
449 
450                 if (!inode)
451                         continue;
452 
453                 /* Either update the children of a tnode that
454                  * already belongs to us or update the child
455                  * to point to ourselves.
456                  */
457                 if (node_parent(inode) == tn)
458                         update_children(inode);
459                 else
460                         node_set_parent(inode, tn);
461         }
462 }
463 
464 static inline void put_child_root(struct key_vector *tp, t_key key,
465                                   struct key_vector *n)
466 {
467         if (IS_TRIE(tp))
468                 rcu_assign_pointer(tp->tnode[0], n);
469         else
470                 put_child(tp, get_index(key, tp), n);
471 }
472 
473 static inline void tnode_free_init(struct key_vector *tn)
474 {
475         tn_info(tn)->rcu.next = NULL;
476 }
477 
478 static inline void tnode_free_append(struct key_vector *tn,
479                                      struct key_vector *n)
480 {
481         tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
482         tn_info(tn)->rcu.next = &tn_info(n)->rcu;
483 }
484 
485 static void tnode_free(struct key_vector *tn)
486 {
487         struct callback_head *head = &tn_info(tn)->rcu;
488 
489         while (head) {
490                 head = head->next;
491                 tnode_free_size += TNODE_SIZE(1ul << tn->bits);
492                 node_free(tn);
493 
494                 tn = container_of(head, struct tnode, rcu)->kv;
495         }
496 
497         if (tnode_free_size >= sysctl_fib_sync_mem) {
498                 tnode_free_size = 0;
499                 synchronize_rcu();
500         }
501 }
502 
503 static struct key_vector *replace(struct trie *t,
504                                   struct key_vector *oldtnode,
505                                   struct key_vector *tn)
506 {
507         struct key_vector *tp = node_parent(oldtnode);
508         unsigned long i;
509 
510         /* setup the parent pointer out of and back into this node */
511         NODE_INIT_PARENT(tn, tp);
512         put_child_root(tp, tn->key, tn);
513 
514         /* update all of the child parent pointers */
515         update_children(tn);
516 
517         /* all pointers should be clean so we are done */
518         tnode_free(oldtnode);
519 
520         /* resize children now that oldtnode is freed */
521         for (i = child_length(tn); i;) {
522                 struct key_vector *inode = get_child(tn, --i);
523 
524                 /* resize child node */
525                 if (tnode_full(tn, inode))
526                         tn = resize(t, inode);
527         }
528 
529         return tp;
530 }
531 
532 static struct key_vector *inflate(struct trie *t,
533                                   struct key_vector *oldtnode)
534 {
535         struct key_vector *tn;
536         unsigned long i;
537         t_key m;
538 
539         pr_debug("In inflate\n");
540 
541         tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
542         if (!tn)
543                 goto notnode;
544 
545         /* prepare oldtnode to be freed */
546         tnode_free_init(oldtnode);
547 
548         /* Assemble all of the pointers in our cluster, in this case that
549          * represents all of the pointers out of our allocated nodes that
550          * point to existing tnodes and the links between our allocated
551          * nodes.
552          */
553         for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
554                 struct key_vector *inode = get_child(oldtnode, --i);
555                 struct key_vector *node0, *node1;
556                 unsigned long j, k;
557 
558                 /* An empty child */
559                 if (!inode)
560                         continue;
561 
562                 /* A leaf or an internal node with skipped bits */
563                 if (!tnode_full(oldtnode, inode)) {
564                         put_child(tn, get_index(inode->key, tn), inode);
565                         continue;
566                 }
567 
568                 /* drop the node in the old tnode free list */
569                 tnode_free_append(oldtnode, inode);
570 
571                 /* An internal node with two children */
572                 if (inode->bits == 1) {
573                         put_child(tn, 2 * i + 1, get_child(inode, 1));
574                         put_child(tn, 2 * i, get_child(inode, 0));
575                         continue;
576                 }
577 
578                 /* We will replace this node 'inode' with two new
579                  * ones, 'node0' and 'node1', each with half of the
580                  * original children. The two new nodes will have
581                  * a position one bit further down the key and this
582                  * means that the "significant" part of their keys
583                  * (see the discussion near the top of this file)
584                  * will differ by one bit, which will be "" in
585                  * node0's key and "1" in node1's key. Since we are
586                  * moving the key position by one step, the bit that
587                  * we are moving away from - the bit at position
588                  * (tn->pos) - is the one that will differ between
589                  * node0 and node1. So... we synthesize that bit in the
590                  * two new keys.
591                  */
592                 node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
593                 if (!node1)
594                         goto nomem;
595                 node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
596 
597                 tnode_free_append(tn, node1);
598                 if (!node0)
599                         goto nomem;
600                 tnode_free_append(tn, node0);
601 
602                 /* populate child pointers in new nodes */
603                 for (k = child_length(inode), j = k / 2; j;) {
604                         put_child(node1, --j, get_child(inode, --k));
605                         put_child(node0, j, get_child(inode, j));
606                         put_child(node1, --j, get_child(inode, --k));
607                         put_child(node0, j, get_child(inode, j));
608                 }
609 
610                 /* link new nodes to parent */
611                 NODE_INIT_PARENT(node1, tn);
612                 NODE_INIT_PARENT(node0, tn);
613 
614                 /* link parent to nodes */
615                 put_child(tn, 2 * i + 1, node1);
616                 put_child(tn, 2 * i, node0);
617         }
618 
619         /* setup the parent pointers into and out of this node */
620         return replace(t, oldtnode, tn);
621 nomem:
622         /* all pointers should be clean so we are done */
623         tnode_free(tn);
624 notnode:
625         return NULL;
626 }
627 
628 static struct key_vector *halve(struct trie *t,
629                                 struct key_vector *oldtnode)
630 {
631         struct key_vector *tn;
632         unsigned long i;
633 
634         pr_debug("In halve\n");
635 
636         tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
637         if (!tn)
638                 goto notnode;
639 
640         /* prepare oldtnode to be freed */
641         tnode_free_init(oldtnode);
642 
643         /* Assemble all of the pointers in our cluster, in this case that
644          * represents all of the pointers out of our allocated nodes that
645          * point to existing tnodes and the links between our allocated
646          * nodes.
647          */
648         for (i = child_length(oldtnode); i;) {
649                 struct key_vector *node1 = get_child(oldtnode, --i);
650                 struct key_vector *node0 = get_child(oldtnode, --i);
651                 struct key_vector *inode;
652 
653                 /* At least one of the children is empty */
654                 if (!node1 || !node0) {
655                         put_child(tn, i / 2, node1 ? : node0);
656                         continue;
657                 }
658 
659                 /* Two nonempty children */
660                 inode = tnode_new(node0->key, oldtnode->pos, 1);
661                 if (!inode)
662                         goto nomem;
663                 tnode_free_append(tn, inode);
664 
665                 /* initialize pointers out of node */
666                 put_child(inode, 1, node1);
667                 put_child(inode, 0, node0);
668                 NODE_INIT_PARENT(inode, tn);
669 
670                 /* link parent to node */
671                 put_child(tn, i / 2, inode);
672         }
673 
674         /* setup the parent pointers into and out of this node */
675         return replace(t, oldtnode, tn);
676 nomem:
677         /* all pointers should be clean so we are done */
678         tnode_free(tn);
679 notnode:
680         return NULL;
681 }
682 
683 static struct key_vector *collapse(struct trie *t,
684                                    struct key_vector *oldtnode)
685 {
686         struct key_vector *n, *tp;
687         unsigned long i;
688 
689         /* scan the tnode looking for that one child that might still exist */
690         for (n = NULL, i = child_length(oldtnode); !n && i;)
691                 n = get_child(oldtnode, --i);
692 
693         /* compress one level */
694         tp = node_parent(oldtnode);
695         put_child_root(tp, oldtnode->key, n);
696         node_set_parent(n, tp);
697 
698         /* drop dead node */
699         node_free(oldtnode);
700 
701         return tp;
702 }
703 
704 static unsigned char update_suffix(struct key_vector *tn)
705 {
706         unsigned char slen = tn->pos;
707         unsigned long stride, i;
708         unsigned char slen_max;
709 
710         /* only vector 0 can have a suffix length greater than or equal to
711          * tn->pos + tn->bits, the second highest node will have a suffix
712          * length at most of tn->pos + tn->bits - 1
713          */
714         slen_max = min_t(unsigned char, tn->pos + tn->bits - 1, tn->slen);
715 
716         /* search though the list of children looking for nodes that might
717          * have a suffix greater than the one we currently have.  This is
718          * why we start with a stride of 2 since a stride of 1 would
719          * represent the nodes with suffix length equal to tn->pos
720          */
721         for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
722                 struct key_vector *n = get_child(tn, i);
723 
724                 if (!n || (n->slen <= slen))
725                         continue;
726 
727                 /* update stride and slen based on new value */
728                 stride <<= (n->slen - slen);
729                 slen = n->slen;
730                 i &= ~(stride - 1);
731 
732                 /* stop searching if we have hit the maximum possible value */
733                 if (slen >= slen_max)
734                         break;
735         }
736 
737         tn->slen = slen;
738 
739         return slen;
740 }
741 
742 /* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
743  * the Helsinki University of Technology and Matti Tikkanen of Nokia
744  * Telecommunications, page 6:
745  * "A node is doubled if the ratio of non-empty children to all
746  * children in the *doubled* node is at least 'high'."
747  *
748  * 'high' in this instance is the variable 'inflate_threshold'. It
749  * is expressed as a percentage, so we multiply it with
750  * child_length() and instead of multiplying by 2 (since the
751  * child array will be doubled by inflate()) and multiplying
752  * the left-hand side by 100 (to handle the percentage thing) we
753  * multiply the left-hand side by 50.
754  *
755  * The left-hand side may look a bit weird: child_length(tn)
756  * - tn->empty_children is of course the number of non-null children
757  * in the current node. tn->full_children is the number of "full"
758  * children, that is non-null tnodes with a skip value of 0.
759  * All of those will be doubled in the resulting inflated tnode, so
760  * we just count them one extra time here.
761  *
762  * A clearer way to write this would be:
763  *
764  * to_be_doubled = tn->full_children;
765  * not_to_be_doubled = child_length(tn) - tn->empty_children -
766  *     tn->full_children;
767  *
768  * new_child_length = child_length(tn) * 2;
769  *
770  * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
771  *      new_child_length;
772  * if (new_fill_factor >= inflate_threshold)
773  *
774  * ...and so on, tho it would mess up the while () loop.
775  *
776  * anyway,
777  * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
778  *      inflate_threshold
779  *
780  * avoid a division:
781  * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
782  *      inflate_threshold * new_child_length
783  *
784  * expand not_to_be_doubled and to_be_doubled, and shorten:
785  * 100 * (child_length(tn) - tn->empty_children +
786  *    tn->full_children) >= inflate_threshold * new_child_length
787  *
788  * expand new_child_length:
789  * 100 * (child_length(tn) - tn->empty_children +
790  *    tn->full_children) >=
791  *      inflate_threshold * child_length(tn) * 2
792  *
793  * shorten again:
794  * 50 * (tn->full_children + child_length(tn) -
795  *    tn->empty_children) >= inflate_threshold *
796  *    child_length(tn)
797  *
798  */
799 static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
800 {
801         unsigned long used = child_length(tn);
802         unsigned long threshold = used;
803 
804         /* Keep root node larger */
805         threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
806         used -= tn_info(tn)->empty_children;
807         used += tn_info(tn)->full_children;
808 
809         /* if bits == KEYLENGTH then pos = 0, and will fail below */
810 
811         return (used > 1) && tn->pos && ((50 * used) >= threshold);
812 }
813 
814 static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
815 {
816         unsigned long used = child_length(tn);
817         unsigned long threshold = used;
818 
819         /* Keep root node larger */
820         threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
821         used -= tn_info(tn)->empty_children;
822 
823         /* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
824 
825         return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
826 }
827 
828 static inline bool should_collapse(struct key_vector *tn)
829 {
830         unsigned long used = child_length(tn);
831 
832         used -= tn_info(tn)->empty_children;
833 
834         /* account for bits == KEYLENGTH case */
835         if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
836                 used -= KEY_MAX;
837 
838         /* One child or none, time to drop us from the trie */
839         return used < 2;
840 }
841 
842 #define MAX_WORK 10
843 static struct key_vector *resize(struct trie *t, struct key_vector *tn)
844 {
845 #ifdef CONFIG_IP_FIB_TRIE_STATS
846         struct trie_use_stats __percpu *stats = t->stats;
847 #endif
848         struct key_vector *tp = node_parent(tn);
849         unsigned long cindex = get_index(tn->key, tp);
850         int max_work = MAX_WORK;
851 
852         pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
853                  tn, inflate_threshold, halve_threshold);
854 
855         /* track the tnode via the pointer from the parent instead of
856          * doing it ourselves.  This way we can let RCU fully do its
857          * thing without us interfering
858          */
859         BUG_ON(tn != get_child(tp, cindex));
860 
861         /* Double as long as the resulting node has a number of
862          * nonempty nodes that are above the threshold.
863          */
864         while (should_inflate(tp, tn) && max_work) {
865                 tp = inflate(t, tn);
866                 if (!tp) {
867 #ifdef CONFIG_IP_FIB_TRIE_STATS
868                         this_cpu_inc(stats->resize_node_skipped);
869 #endif
870                         break;
871                 }
872 
873                 max_work--;
874                 tn = get_child(tp, cindex);
875         }
876 
877         /* update parent in case inflate failed */
878         tp = node_parent(tn);
879 
880         /* Return if at least one inflate is run */
881         if (max_work != MAX_WORK)
882                 return tp;
883 
884         /* Halve as long as the number of empty children in this
885          * node is above threshold.
886          */
887         while (should_halve(tp, tn) && max_work) {
888                 tp = halve(t, tn);
889                 if (!tp) {
890 #ifdef CONFIG_IP_FIB_TRIE_STATS
891                         this_cpu_inc(stats->resize_node_skipped);
892 #endif
893                         break;
894                 }
895 
896                 max_work--;
897                 tn = get_child(tp, cindex);
898         }
899 
900         /* Only one child remains */
901         if (should_collapse(tn))
902                 return collapse(t, tn);
903 
904         /* update parent in case halve failed */
905         return node_parent(tn);
906 }
907 
908 static void node_pull_suffix(struct key_vector *tn, unsigned char slen)
909 {
910         unsigned char node_slen = tn->slen;
911 
912         while ((node_slen > tn->pos) && (node_slen > slen)) {
913                 slen = update_suffix(tn);
914                 if (node_slen == slen)
915                         break;
916 
917                 tn = node_parent(tn);
918                 node_slen = tn->slen;
919         }
920 }
921 
922 static void node_push_suffix(struct key_vector *tn, unsigned char slen)
923 {
924         while (tn->slen < slen) {
925                 tn->slen = slen;
926                 tn = node_parent(tn);
927         }
928 }
929 
930 /* rcu_read_lock needs to be hold by caller from readside */
931 static struct key_vector *fib_find_node(struct trie *t,
932                                         struct key_vector **tp, u32 key)
933 {
934         struct key_vector *pn, *n = t->kv;
935         unsigned long index = 0;
936 
937         do {
938                 pn = n;
939                 n = get_child_rcu(n, index);
940 
941                 if (!n)
942                         break;
943 
944                 index = get_cindex(key, n);
945 
946                 /* This bit of code is a bit tricky but it combines multiple
947                  * checks into a single check.  The prefix consists of the
948                  * prefix plus zeros for the bits in the cindex. The index
949                  * is the difference between the key and this value.  From
950                  * this we can actually derive several pieces of data.
951                  *   if (index >= (1ul << bits))
952                  *     we have a mismatch in skip bits and failed
953                  *   else
954                  *     we know the value is cindex
955                  *
956                  * This check is safe even if bits == KEYLENGTH due to the
957                  * fact that we can only allocate a node with 32 bits if a
958                  * long is greater than 32 bits.
959                  */
960                 if (index >= (1ul << n->bits)) {
961                         n = NULL;
962                         break;
963                 }
964 
965                 /* keep searching until we find a perfect match leaf or NULL */
966         } while (IS_TNODE(n));
967 
968         *tp = pn;
969 
970         return n;
971 }
972 
973 /* Return the first fib alias matching TOS with
974  * priority less than or equal to PRIO.
975  */
976 static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
977                                         u8 tos, u32 prio, u32 tb_id)
978 {
979         struct fib_alias *fa;
980 
981         if (!fah)
982                 return NULL;
983 
984         hlist_for_each_entry(fa, fah, fa_list) {
985                 if (fa->fa_slen < slen)
986                         continue;
987                 if (fa->fa_slen != slen)
988                         break;
989                 if (fa->tb_id > tb_id)
990                         continue;
991                 if (fa->tb_id != tb_id)
992                         break;
993                 if (fa->fa_tos > tos)
994                         continue;
995                 if (fa->fa_info->fib_priority >= prio || fa->fa_tos < tos)
996                         return fa;
997         }
998 
999         return NULL;
1000 }
1001 
1002 static void trie_rebalance(struct trie *t, struct key_vector *tn)
1003 {
1004         while (!IS_TRIE(tn))
1005                 tn = resize(t, tn);
1006 }
1007 
1008 static int fib_insert_node(struct trie *t, struct key_vector *tp,
1009                            struct fib_alias *new, t_key key)
1010 {
1011         struct key_vector *n, *l;
1012 
1013         l = leaf_new(key, new);
1014         if (!l)
1015                 goto noleaf;
1016 
1017         /* retrieve child from parent node */
1018         n = get_child(tp, get_index(key, tp));
1019 
1020         /* Case 2: n is a LEAF or a TNODE and the key doesn't match.
1021          *
1022          *  Add a new tnode here
1023          *  first tnode need some special handling
1024          *  leaves us in position for handling as case 3
1025          */
1026         if (n) {
1027                 struct key_vector *tn;
1028 
1029                 tn = tnode_new(key, __fls(key ^ n->key), 1);
1030                 if (!tn)
1031                         goto notnode;
1032 
1033                 /* initialize routes out of node */
1034                 NODE_INIT_PARENT(tn, tp);
1035                 put_child(tn, get_index(key, tn) ^ 1, n);
1036 
1037                 /* start adding routes into the node */
1038                 put_child_root(tp, key, tn);
1039                 node_set_parent(n, tn);
1040 
1041                 /* parent now has a NULL spot where the leaf can go */
1042                 tp = tn;
1043         }
1044 
1045         /* Case 3: n is NULL, and will just insert a new leaf */
1046         node_push_suffix(tp, new->fa_slen);
1047         NODE_INIT_PARENT(l, tp);
1048         put_child_root(tp, key, l);
1049         trie_rebalance(t, tp);
1050 
1051         return 0;
1052 notnode:
1053         node_free(l);
1054 noleaf:
1055         return -ENOMEM;
1056 }
1057 
1058 /* fib notifier for ADD is sent before calling fib_insert_alias with
1059  * the expectation that the only possible failure ENOMEM
1060  */
1061 static int fib_insert_alias(struct trie *t, struct key_vector *tp,
1062                             struct key_vector *l, struct fib_alias *new,
1063                             struct fib_alias *fa, t_key key)
1064 {
1065         if (!l)
1066                 return fib_insert_node(t, tp, new, key);
1067 
1068         if (fa) {
1069                 hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
1070         } else {
1071                 struct fib_alias *last;
1072 
1073                 hlist_for_each_entry(last, &l->leaf, fa_list) {
1074                         if (new->fa_slen < last->fa_slen)
1075                                 break;
1076                         if ((new->fa_slen == last->fa_slen) &&
1077                             (new->tb_id > last->tb_id))
1078                                 break;
1079                         fa = last;
1080                 }
1081 
1082                 if (fa)
1083                         hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
1084                 else
1085                         hlist_add_head_rcu(&new->fa_list, &l->leaf);
1086         }
1087 
1088         /* if we added to the tail node then we need to update slen */
1089         if (l->slen < new->fa_slen) {
1090                 l->slen = new->fa_slen;
1091                 node_push_suffix(tp, new->fa_slen);
1092         }
1093 
1094         return 0;
1095 }
1096 
1097 static bool fib_valid_key_len(u32 key, u8 plen, struct netlink_ext_ack *extack)
1098 {
1099         if (plen > KEYLENGTH) {
1100                 NL_SET_ERR_MSG(extack, "Invalid prefix length");
1101                 return false;
1102         }
1103 
1104         if ((plen < KEYLENGTH) && (key << plen)) {
1105                 NL_SET_ERR_MSG(extack,
1106                                "Invalid prefix for given prefix length");
1107                 return false;
1108         }
1109 
1110         return true;
1111 }
1112 
1113 /* Caller must hold RTNL. */
1114 int fib_table_insert(struct net *net, struct fib_table *tb,
1115                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1116 {
1117         enum fib_event_type event = FIB_EVENT_ENTRY_ADD;
1118         struct trie *t = (struct trie *)tb->tb_data;
1119         struct fib_alias *fa, *new_fa;
1120         struct key_vector *l, *tp;
1121         u16 nlflags = NLM_F_EXCL;
1122         struct fib_info *fi;
1123         u8 plen = cfg->fc_dst_len;
1124         u8 slen = KEYLENGTH - plen;
1125         u8 tos = cfg->fc_tos;
1126         u32 key;
1127         int err;
1128 
1129         key = ntohl(cfg->fc_dst);
1130 
1131         if (!fib_valid_key_len(key, plen, extack))
1132                 return -EINVAL;
1133 
1134         pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
1135 
1136         fi = fib_create_info(cfg, extack);
1137         if (IS_ERR(fi)) {
1138                 err = PTR_ERR(fi);
1139                 goto err;
1140         }
1141 
1142         l = fib_find_node(t, &tp, key);
1143         fa = l ? fib_find_alias(&l->leaf, slen, tos, fi->fib_priority,
1144                                 tb->tb_id) : NULL;
1145 
1146         /* Now fa, if non-NULL, points to the first fib alias
1147          * with the same keys [prefix,tos,priority], if such key already
1148          * exists or to the node before which we will insert new one.
1149          *
1150          * If fa is NULL, we will need to allocate a new one and
1151          * insert to the tail of the section matching the suffix length
1152          * of the new alias.
1153          */
1154 
1155         if (fa && fa->fa_tos == tos &&
1156             fa->fa_info->fib_priority == fi->fib_priority) {
1157                 struct fib_alias *fa_first, *fa_match;
1158 
1159                 err = -EEXIST;
1160                 if (cfg->fc_nlflags & NLM_F_EXCL)
1161                         goto out;
1162 
1163                 nlflags &= ~NLM_F_EXCL;
1164 
1165                 /* We have 2 goals:
1166                  * 1. Find exact match for type, scope, fib_info to avoid
1167                  * duplicate routes
1168                  * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
1169                  */
1170                 fa_match = NULL;
1171                 fa_first = fa;
1172                 hlist_for_each_entry_from(fa, fa_list) {
1173                         if ((fa->fa_slen != slen) ||
1174                             (fa->tb_id != tb->tb_id) ||
1175                             (fa->fa_tos != tos))
1176                                 break;
1177                         if (fa->fa_info->fib_priority != fi->fib_priority)
1178                                 break;
1179                         if (fa->fa_type == cfg->fc_type &&
1180                             fa->fa_info == fi) {
1181                                 fa_match = fa;
1182                                 break;
1183                         }
1184                 }
1185 
1186                 if (cfg->fc_nlflags & NLM_F_REPLACE) {
1187                         struct fib_info *fi_drop;
1188                         u8 state;
1189 
1190                         nlflags |= NLM_F_REPLACE;
1191                         fa = fa_first;
1192                         if (fa_match) {
1193                                 if (fa == fa_match)
1194                                         err = 0;
1195                                 goto out;
1196                         }
1197                         err = -ENOBUFS;
1198                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1199                         if (!new_fa)
1200                                 goto out;
1201 
1202                         fi_drop = fa->fa_info;
1203                         new_fa->fa_tos = fa->fa_tos;
1204                         new_fa->fa_info = fi;
1205                         new_fa->fa_type = cfg->fc_type;
1206                         state = fa->fa_state;
1207                         new_fa->fa_state = state & ~FA_S_ACCESSED;
1208                         new_fa->fa_slen = fa->fa_slen;
1209                         new_fa->tb_id = tb->tb_id;
1210                         new_fa->fa_default = -1;
1211 
1212                         err = call_fib_entry_notifiers(net,
1213                                                        FIB_EVENT_ENTRY_REPLACE,
1214                                                        key, plen, new_fa,
1215                                                        extack);
1216                         if (err)
1217                                 goto out_free_new_fa;
1218 
1219                         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
1220                                   tb->tb_id, &cfg->fc_nlinfo, nlflags);
1221 
1222                         hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
1223 
1224                         alias_free_mem_rcu(fa);
1225 
1226                         fib_release_info(fi_drop);
1227                         if (state & FA_S_ACCESSED)
1228                                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1229 
1230                         goto succeeded;
1231                 }
1232                 /* Error if we find a perfect match which
1233                  * uses the same scope, type, and nexthop
1234                  * information.
1235                  */
1236                 if (fa_match)
1237                         goto out;
1238 
1239                 if (cfg->fc_nlflags & NLM_F_APPEND) {
1240                         event = FIB_EVENT_ENTRY_APPEND;
1241                         nlflags |= NLM_F_APPEND;
1242                 } else {
1243                         fa = fa_first;
1244                 }
1245         }
1246         err = -ENOENT;
1247         if (!(cfg->fc_nlflags & NLM_F_CREATE))
1248                 goto out;
1249 
1250         nlflags |= NLM_F_CREATE;
1251         err = -ENOBUFS;
1252         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1253         if (!new_fa)
1254                 goto out;
1255 
1256         new_fa->fa_info = fi;
1257         new_fa->fa_tos = tos;
1258         new_fa->fa_type = cfg->fc_type;
1259         new_fa->fa_state = 0;
1260         new_fa->fa_slen = slen;
1261         new_fa->tb_id = tb->tb_id;
1262         new_fa->fa_default = -1;
1263 
1264         err = call_fib_entry_notifiers(net, event, key, plen, new_fa, extack);
1265         if (err)
1266                 goto out_free_new_fa;
1267 
1268         /* Insert new entry to the list. */
1269         err = fib_insert_alias(t, tp, l, new_fa, fa, key);
1270         if (err)
1271                 goto out_fib_notif;
1272 
1273         if (!plen)
1274                 tb->tb_num_default++;
1275 
1276         rt_cache_flush(cfg->fc_nlinfo.nl_net);
1277         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
1278                   &cfg->fc_nlinfo, nlflags);
1279 succeeded:
1280         return 0;
1281 
1282 out_fib_notif:
1283         /* notifier was sent that entry would be added to trie, but
1284          * the add failed and need to recover. Only failure for
1285          * fib_insert_alias is ENOMEM.
1286          */
1287         NL_SET_ERR_MSG(extack, "Failed to insert route into trie");
1288         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key,
1289                                  plen, new_fa, NULL);
1290 out_free_new_fa:
1291         kmem_cache_free(fn_alias_kmem, new_fa);
1292 out:
1293         fib_release_info(fi);
1294 err:
1295         return err;
1296 }
1297 
1298 static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
1299 {
1300         t_key prefix = n->key;
1301 
1302         return (key ^ prefix) & (prefix | -prefix);
1303 }
1304 
1305 /* should be called with rcu_read_lock */
1306 int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
1307                      struct fib_result *res, int fib_flags)
1308 {
1309         struct trie *t = (struct trie *) tb->tb_data;
1310 #ifdef CONFIG_IP_FIB_TRIE_STATS
1311         struct trie_use_stats __percpu *stats = t->stats;
1312 #endif
1313         const t_key key = ntohl(flp->daddr);
1314         struct key_vector *n, *pn;
1315         struct fib_alias *fa;
1316         unsigned long index;
1317         t_key cindex;
1318 
1319         pn = t->kv;
1320         cindex = 0;
1321 
1322         n = get_child_rcu(pn, cindex);
1323         if (!n) {
1324                 trace_fib_table_lookup(tb->tb_id, flp, NULL, -EAGAIN);
1325                 return -EAGAIN;
1326         }
1327 
1328 #ifdef CONFIG_IP_FIB_TRIE_STATS
1329         this_cpu_inc(stats->gets);
1330 #endif
1331 
1332         /* Step 1: Travel to the longest prefix match in the trie */
1333         for (;;) {
1334                 index = get_cindex(key, n);
1335 
1336                 /* This bit of code is a bit tricky but it combines multiple
1337                  * checks into a single check.  The prefix consists of the
1338                  * prefix plus zeros for the "bits" in the prefix. The index
1339                  * is the difference between the key and this value.  From
1340                  * this we can actually derive several pieces of data.
1341                  *   if (index >= (1ul << bits))
1342                  *     we have a mismatch in skip bits and failed
1343                  *   else
1344                  *     we know the value is cindex
1345                  *
1346                  * This check is safe even if bits == KEYLENGTH due to the
1347                  * fact that we can only allocate a node with 32 bits if a
1348                  * long is greater than 32 bits.
1349                  */
1350                 if (index >= (1ul << n->bits))
1351                         break;
1352 
1353                 /* we have found a leaf. Prefixes have already been compared */
1354                 if (IS_LEAF(n))
1355                         goto found;
1356 
1357                 /* only record pn and cindex if we are going to be chopping
1358                  * bits later.  Otherwise we are just wasting cycles.
1359                  */
1360                 if (n->slen > n->pos) {
1361                         pn = n;
1362                         cindex = index;
1363                 }
1364 
1365                 n = get_child_rcu(n, index);
1366                 if (unlikely(!n))
1367                         goto backtrace;
1368         }
1369 
1370         /* Step 2: Sort out leaves and begin backtracing for longest prefix */
1371         for (;;) {
1372                 /* record the pointer where our next node pointer is stored */
1373                 struct key_vector __rcu **cptr = n->tnode;
1374 
1375                 /* This test verifies that none of the bits that differ
1376                  * between the key and the prefix exist in the region of
1377                  * the lsb and higher in the prefix.
1378                  */
1379                 if (unlikely(prefix_mismatch(key, n)) || (n->slen == n->pos))
1380                         goto backtrace;
1381 
1382                 /* exit out and process leaf */
1383                 if (unlikely(IS_LEAF(n)))
1384                         break;
1385 
1386                 /* Don't bother recording parent info.  Since we are in
1387                  * prefix match mode we will have to come back to wherever
1388                  * we started this traversal anyway
1389                  */
1390 
1391                 while ((n = rcu_dereference(*cptr)) == NULL) {
1392 backtrace:
1393 #ifdef CONFIG_IP_FIB_TRIE_STATS
1394                         if (!n)
1395                                 this_cpu_inc(stats->null_node_hit);
1396 #endif
1397                         /* If we are at cindex 0 there are no more bits for
1398                          * us to strip at this level so we must ascend back
1399                          * up one level to see if there are any more bits to
1400                          * be stripped there.
1401                          */
1402                         while (!cindex) {
1403                                 t_key pkey = pn->key;
1404 
1405                                 /* If we don't have a parent then there is
1406                                  * nothing for us to do as we do not have any
1407                                  * further nodes to parse.
1408                                  */
1409                                 if (IS_TRIE(pn)) {
1410                                         trace_fib_table_lookup(tb->tb_id, flp,
1411                                                                NULL, -EAGAIN);
1412                                         return -EAGAIN;
1413                                 }
1414 #ifdef CONFIG_IP_FIB_TRIE_STATS
1415                                 this_cpu_inc(stats->backtrack);
1416 #endif
1417                                 /* Get Child's index */
1418                                 pn = node_parent_rcu(pn);
1419                                 cindex = get_index(pkey, pn);
1420                         }
1421 
1422                         /* strip the least significant bit from the cindex */
1423                         cindex &= cindex - 1;
1424 
1425                         /* grab pointer for next child node */
1426                         cptr = &pn->tnode[cindex];
1427                 }
1428         }
1429 
1430 found:
1431         /* this line carries forward the xor from earlier in the function */
1432         index = key ^ n->key;
1433 
1434         /* Step 3: Process the leaf, if that fails fall back to backtracing */
1435         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
1436                 struct fib_info *fi = fa->fa_info;
1437                 int nhsel, err;
1438 
1439                 if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) {
1440                         if (index >= (1ul << fa->fa_slen))
1441                                 continue;
1442                 }
1443                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1444                         continue;
1445                 if (fi->fib_dead)
1446                         continue;
1447                 if (fa->fa_info->fib_scope < flp->flowi4_scope)
1448                         continue;
1449                 fib_alias_accessed(fa);
1450                 err = fib_props[fa->fa_type].error;
1451                 if (unlikely(err < 0)) {
1452 #ifdef CONFIG_IP_FIB_TRIE_STATS
1453                         this_cpu_inc(stats->semantic_match_passed);
1454 #endif
1455                         trace_fib_table_lookup(tb->tb_id, flp, NULL, err);
1456                         return err;
1457                 }
1458                 if (fi->fib_flags & RTNH_F_DEAD)
1459                         continue;
1460                 for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
1461                         struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
1462 
1463                         if (nhc->nhc_flags & RTNH_F_DEAD)
1464                                 continue;
1465                         if (ip_ignore_linkdown(nhc->nhc_dev) &&
1466                             nhc->nhc_flags & RTNH_F_LINKDOWN &&
1467                             !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
1468                                 continue;
1469                         if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) {
1470                                 if (flp->flowi4_oif &&
1471                                     flp->flowi4_oif != nhc->nhc_oif)
1472                                         continue;
1473                         }
1474 
1475                         if (!(fib_flags & FIB_LOOKUP_NOREF))
1476                                 refcount_inc(&fi->fib_clntref);
1477 
1478                         res->prefix = htonl(n->key);
1479                         res->prefixlen = KEYLENGTH - fa->fa_slen;
1480                         res->nh_sel = nhsel;
1481                         res->nhc = nhc;
1482                         res->type = fa->fa_type;
1483                         res->scope = fi->fib_scope;
1484                         res->fi = fi;
1485                         res->table = tb;
1486                         res->fa_head = &n->leaf;
1487 #ifdef CONFIG_IP_FIB_TRIE_STATS
1488                         this_cpu_inc(stats->semantic_match_passed);
1489 #endif
1490                         trace_fib_table_lookup(tb->tb_id, flp, nhc, err);
1491 
1492                         return err;
1493                 }
1494         }
1495 #ifdef CONFIG_IP_FIB_TRIE_STATS
1496         this_cpu_inc(stats->semantic_match_miss);
1497 #endif
1498         goto backtrace;
1499 }
1500 EXPORT_SYMBOL_GPL(fib_table_lookup);
1501 
1502 static void fib_remove_alias(struct trie *t, struct key_vector *tp,
1503                              struct key_vector *l, struct fib_alias *old)
1504 {
1505         /* record the location of the previous list_info entry */
1506         struct hlist_node **pprev = old->fa_list.pprev;
1507         struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
1508 
1509         /* remove the fib_alias from the list */
1510         hlist_del_rcu(&old->fa_list);
1511 
1512         /* if we emptied the list this leaf will be freed and we can sort
1513          * out parent suffix lengths as a part of trie_rebalance
1514          */
1515         if (hlist_empty(&l->leaf)) {
1516                 if (tp->slen == l->slen)
1517                         node_pull_suffix(tp, tp->pos);
1518                 put_child_root(tp, l->key, NULL);
1519                 node_free(l);
1520                 trie_rebalance(t, tp);
1521                 return;
1522         }
1523 
1524         /* only access fa if it is pointing at the last valid hlist_node */
1525         if (*pprev)
1526                 return;
1527 
1528         /* update the trie with the latest suffix length */
1529         l->slen = fa->fa_slen;
1530         node_pull_suffix(tp, fa->fa_slen);
1531 }
1532 
1533 /* Caller must hold RTNL. */
1534 int fib_table_delete(struct net *net, struct fib_table *tb,
1535                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1536 {
1537         struct trie *t = (struct trie *) tb->tb_data;
1538         struct fib_alias *fa, *fa_to_delete;
1539         struct key_vector *l, *tp;
1540         u8 plen = cfg->fc_dst_len;
1541         u8 slen = KEYLENGTH - plen;
1542         u8 tos = cfg->fc_tos;
1543         u32 key;
1544 
1545         key = ntohl(cfg->fc_dst);
1546 
1547         if (!fib_valid_key_len(key, plen, extack))
1548                 return -EINVAL;
1549 
1550         l = fib_find_node(t, &tp, key);
1551         if (!l)
1552                 return -ESRCH;
1553 
1554         fa = fib_find_alias(&l->leaf, slen, tos, 0, tb->tb_id);
1555         if (!fa)
1556                 return -ESRCH;
1557 
1558         pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
1559 
1560         fa_to_delete = NULL;
1561         hlist_for_each_entry_from(fa, fa_list) {
1562                 struct fib_info *fi = fa->fa_info;
1563 
1564                 if ((fa->fa_slen != slen) ||
1565                     (fa->tb_id != tb->tb_id) ||
1566                     (fa->fa_tos != tos))
1567                         break;
1568 
1569                 if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
1570                     (cfg->fc_scope == RT_SCOPE_NOWHERE ||
1571                      fa->fa_info->fib_scope == cfg->fc_scope) &&
1572                     (!cfg->fc_prefsrc ||
1573                      fi->fib_prefsrc == cfg->fc_prefsrc) &&
1574                     (!cfg->fc_protocol ||
1575                      fi->fib_protocol == cfg->fc_protocol) &&
1576                     fib_nh_match(cfg, fi, extack) == 0 &&
1577                     fib_metrics_match(cfg, fi)) {
1578                         fa_to_delete = fa;
1579                         break;
1580                 }
1581         }
1582 
1583         if (!fa_to_delete)
1584                 return -ESRCH;
1585 
1586         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key, plen,
1587                                  fa_to_delete, extack);
1588         rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
1589                   &cfg->fc_nlinfo, 0);
1590 
1591         if (!plen)
1592                 tb->tb_num_default--;
1593 
1594         fib_remove_alias(t, tp, l, fa_to_delete);
1595 
1596         if (fa_to_delete->fa_state & FA_S_ACCESSED)
1597                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1598 
1599         fib_release_info(fa_to_delete->fa_info);
1600         alias_free_mem_rcu(fa_to_delete);
1601         return 0;
1602 }
1603 
1604 /* Scan for the next leaf starting at the provided key value */
1605 static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
1606 {
1607         struct key_vector *pn, *n = *tn;
1608         unsigned long cindex;
1609 
1610         /* this loop is meant to try and find the key in the trie */
1611         do {
1612                 /* record parent and next child index */
1613                 pn = n;
1614                 cindex = (key > pn->key) ? get_index(key, pn) : 0;
1615 
1616                 if (cindex >> pn->bits)
1617                         break;
1618 
1619                 /* descend into the next child */
1620                 n = get_child_rcu(pn, cindex++);
1621                 if (!n)
1622                         break;
1623 
1624                 /* guarantee forward progress on the keys */
1625                 if (IS_LEAF(n) && (n->key >= key))
1626                         goto found;
1627         } while (IS_TNODE(n));
1628 
1629         /* this loop will search for the next leaf with a greater key */
1630         while (!IS_TRIE(pn)) {
1631                 /* if we exhausted the parent node we will need to climb */
1632                 if (cindex >= (1ul << pn->bits)) {
1633                         t_key pkey = pn->key;
1634 
1635                         pn = node_parent_rcu(pn);
1636                         cindex = get_index(pkey, pn) + 1;
1637                         continue;
1638                 }
1639 
1640                 /* grab the next available node */
1641                 n = get_child_rcu(pn, cindex++);
1642                 if (!n)
1643                         continue;
1644 
1645                 /* no need to compare keys since we bumped the index */
1646                 if (IS_LEAF(n))
1647                         goto found;
1648 
1649                 /* Rescan start scanning in new node */
1650                 pn = n;
1651                 cindex = 0;
1652         }
1653 
1654         *tn = pn;
1655         return NULL; /* Root of trie */
1656 found:
1657         /* if we are at the limit for keys just return NULL for the tnode */
1658         *tn = pn;
1659         return n;
1660 }
1661 
1662 static void fib_trie_free(struct fib_table *tb)
1663 {
1664         struct trie *t = (struct trie *)tb->tb_data;
1665         struct key_vector *pn = t->kv;
1666         unsigned long cindex = 1;
1667         struct hlist_node *tmp;
1668         struct fib_alias *fa;
1669 
1670         /* walk trie in reverse order and free everything */
1671         for (;;) {
1672                 struct key_vector *n;
1673 
1674                 if (!(cindex--)) {
1675                         t_key pkey = pn->key;
1676 
1677                         if (IS_TRIE(pn))
1678                                 break;
1679 
1680                         n = pn;
1681                         pn = node_parent(pn);
1682 
1683                         /* drop emptied tnode */
1684                         put_child_root(pn, n->key, NULL);
1685                         node_free(n);
1686 
1687                         cindex = get_index(pkey, pn);
1688 
1689                         continue;
1690                 }
1691 
1692                 /* grab the next available node */
1693                 n = get_child(pn, cindex);
1694                 if (!n)
1695                         continue;
1696 
1697                 if (IS_TNODE(n)) {
1698                         /* record pn and cindex for leaf walking */
1699                         pn = n;
1700                         cindex = 1ul << n->bits;
1701 
1702                         continue;
1703                 }
1704 
1705                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1706                         hlist_del_rcu(&fa->fa_list);
1707                         alias_free_mem_rcu(fa);
1708                 }
1709 
1710                 put_child_root(pn, n->key, NULL);
1711                 node_free(n);
1712         }
1713 
1714 #ifdef CONFIG_IP_FIB_TRIE_STATS
1715         free_percpu(t->stats);
1716 #endif
1717         kfree(tb);
1718 }
1719 
1720 struct fib_table *fib_trie_unmerge(struct fib_table *oldtb)
1721 {
1722         struct trie *ot = (struct trie *)oldtb->tb_data;
1723         struct key_vector *l, *tp = ot->kv;
1724         struct fib_table *local_tb;
1725         struct fib_alias *fa;
1726         struct trie *lt;
1727         t_key key = 0;
1728 
1729         if (oldtb->tb_data == oldtb->__data)
1730                 return oldtb;
1731 
1732         local_tb = fib_trie_table(RT_TABLE_LOCAL, NULL);
1733         if (!local_tb)
1734                 return NULL;
1735 
1736         lt = (struct trie *)local_tb->tb_data;
1737 
1738         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1739                 struct key_vector *local_l = NULL, *local_tp;
1740 
1741                 hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1742                         struct fib_alias *new_fa;
1743 
1744                         if (local_tb->tb_id != fa->tb_id)
1745                                 continue;
1746 
1747                         /* clone fa for new local table */
1748                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1749                         if (!new_fa)
1750                                 goto out;
1751 
1752                         memcpy(new_fa, fa, sizeof(*fa));
1753 
1754                         /* insert clone into table */
1755                         if (!local_l)
1756                                 local_l = fib_find_node(lt, &local_tp, l->key);
1757 
1758                         if (fib_insert_alias(lt, local_tp, local_l, new_fa,
1759                                              NULL, l->key)) {
1760                                 kmem_cache_free(fn_alias_kmem, new_fa);
1761                                 goto out;
1762                         }
1763                 }
1764 
1765                 /* stop loop if key wrapped back to 0 */
1766                 key = l->key + 1;
1767                 if (key < l->key)
1768                         break;
1769         }
1770 
1771         return local_tb;
1772 out:
1773         fib_trie_free(local_tb);
1774 
1775         return NULL;
1776 }
1777 
1778 /* Caller must hold RTNL */
1779 void fib_table_flush_external(struct fib_table *tb)
1780 {
1781         struct trie *t = (struct trie *)tb->tb_data;
1782         struct key_vector *pn = t->kv;
1783         unsigned long cindex = 1;
1784         struct hlist_node *tmp;
1785         struct fib_alias *fa;
1786 
1787         /* walk trie in reverse order */
1788         for (;;) {
1789                 unsigned char slen = 0;
1790                 struct key_vector *n;
1791 
1792                 if (!(cindex--)) {
1793                         t_key pkey = pn->key;
1794 
1795                         /* cannot resize the trie vector */
1796                         if (IS_TRIE(pn))
1797                                 break;
1798 
1799                         /* update the suffix to address pulled leaves */
1800                         if (pn->slen > pn->pos)
1801                                 update_suffix(pn);
1802 
1803                         /* resize completed node */
1804                         pn = resize(t, pn);
1805                         cindex = get_index(pkey, pn);
1806 
1807                         continue;
1808                 }
1809 
1810                 /* grab the next available node */
1811                 n = get_child(pn, cindex);
1812                 if (!n)
1813                         continue;
1814 
1815                 if (IS_TNODE(n)) {
1816                         /* record pn and cindex for leaf walking */
1817                         pn = n;
1818                         cindex = 1ul << n->bits;
1819 
1820                         continue;
1821                 }
1822 
1823                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1824                         /* if alias was cloned to local then we just
1825                          * need to remove the local copy from main
1826                          */
1827                         if (tb->tb_id != fa->tb_id) {
1828                                 hlist_del_rcu(&fa->fa_list);
1829                                 alias_free_mem_rcu(fa);
1830                                 continue;
1831                         }
1832 
1833                         /* record local slen */
1834                         slen = fa->fa_slen;
1835                 }
1836 
1837                 /* update leaf slen */
1838                 n->slen = slen;
1839 
1840                 if (hlist_empty(&n->leaf)) {
1841                         put_child_root(pn, n->key, NULL);
1842                         node_free(n);
1843                 }
1844         }
1845 }
1846 
1847 /* Caller must hold RTNL. */
1848 int fib_table_flush(struct net *net, struct fib_table *tb, bool flush_all)
1849 {
1850         struct trie *t = (struct trie *)tb->tb_data;
1851         struct key_vector *pn = t->kv;
1852         unsigned long cindex = 1;
1853         struct hlist_node *tmp;
1854         struct fib_alias *fa;
1855         int found = 0;
1856 
1857         /* walk trie in reverse order */
1858         for (;;) {
1859                 unsigned char slen = 0;
1860                 struct key_vector *n;
1861 
1862                 if (!(cindex--)) {
1863                         t_key pkey = pn->key;
1864 
1865                         /* cannot resize the trie vector */
1866                         if (IS_TRIE(pn))
1867                                 break;
1868 
1869                         /* update the suffix to address pulled leaves */
1870                         if (pn->slen > pn->pos)
1871                                 update_suffix(pn);
1872 
1873                         /* resize completed node */
1874                         pn = resize(t, pn);
1875                         cindex = get_index(pkey, pn);
1876 
1877                         continue;
1878                 }
1879 
1880                 /* grab the next available node */
1881                 n = get_child(pn, cindex);
1882                 if (!n)
1883                         continue;
1884 
1885                 if (IS_TNODE(n)) {
1886                         /* record pn and cindex for leaf walking */
1887                         pn = n;
1888                         cindex = 1ul << n->bits;
1889 
1890                         continue;
1891                 }
1892 
1893                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1894                         struct fib_info *fi = fa->fa_info;
1895 
1896                         if (!fi || tb->tb_id != fa->tb_id ||
1897                             (!(fi->fib_flags & RTNH_F_DEAD) &&
1898                              !fib_props[fa->fa_type].error)) {
1899                                 slen = fa->fa_slen;
1900                                 continue;
1901                         }
1902 
1903                         /* Do not flush error routes if network namespace is
1904                          * not being dismantled
1905                          */
1906                         if (!flush_all && fib_props[fa->fa_type].error) {
1907                                 slen = fa->fa_slen;
1908                                 continue;
1909                         }
1910 
1911                         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
1912                                                  n->key,
1913                                                  KEYLENGTH - fa->fa_slen, fa,
1914                                                  NULL);
1915                         hlist_del_rcu(&fa->fa_list);
1916                         fib_release_info(fa->fa_info);
1917                         alias_free_mem_rcu(fa);
1918                         found++;
1919                 }
1920 
1921                 /* update leaf slen */
1922                 n->slen = slen;
1923 
1924                 if (hlist_empty(&n->leaf)) {
1925                         put_child_root(pn, n->key, NULL);
1926                         node_free(n);
1927                 }
1928         }
1929 
1930         pr_debug("trie_flush found=%d\n", found);
1931         return found;
1932 }
1933 
1934 static void fib_leaf_notify(struct net *net, struct key_vector *l,
1935                             struct fib_table *tb, struct notifier_block *nb)
1936 {
1937         struct fib_alias *fa;
1938 
1939         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1940                 struct fib_info *fi = fa->fa_info;
1941 
1942                 if (!fi)
1943                         continue;
1944 
1945                 /* local and main table can share the same trie,
1946                  * so don't notify twice for the same entry.
1947                  */
1948                 if (tb->tb_id != fa->tb_id)
1949                         continue;
1950 
1951                 call_fib_entry_notifier(nb, net, FIB_EVENT_ENTRY_ADD, l->key,
1952                                         KEYLENGTH - fa->fa_slen, fa);
1953         }
1954 }
1955 
1956 static void fib_table_notify(struct net *net, struct fib_table *tb,
1957                              struct notifier_block *nb)
1958 {
1959         struct trie *t = (struct trie *)tb->tb_data;
1960         struct key_vector *l, *tp = t->kv;
1961         t_key key = 0;
1962 
1963         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1964                 fib_leaf_notify(net, l, tb, nb);
1965 
1966                 key = l->key + 1;
1967                 /* stop in case of wrap around */
1968                 if (key < l->key)
1969                         break;
1970         }
1971 }
1972 
1973 void fib_notify(struct net *net, struct notifier_block *nb)
1974 {
1975         unsigned int h;
1976 
1977         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
1978                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
1979                 struct fib_table *tb;
1980 
1981                 hlist_for_each_entry_rcu(tb, head, tb_hlist)
1982                         fib_table_notify(net, tb, nb);
1983         }
1984 }
1985 
1986 static void __trie_free_rcu(struct rcu_head *head)
1987 {
1988         struct fib_table *tb = container_of(head, struct fib_table, rcu);
1989 #ifdef CONFIG_IP_FIB_TRIE_STATS
1990         struct trie *t = (struct trie *)tb->tb_data;
1991 
1992         if (tb->tb_data == tb->__data)
1993                 free_percpu(t->stats);
1994 #endif /* CONFIG_IP_FIB_TRIE_STATS */
1995         kfree(tb);
1996 }
1997 
1998 void fib_free_table(struct fib_table *tb)
1999 {
2000         call_rcu(&tb->rcu, __trie_free_rcu);
2001 }
2002 
2003 static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
2004                              struct sk_buff *skb, struct netlink_callback *cb,
2005                              struct fib_dump_filter *filter)
2006 {
2007         unsigned int flags = NLM_F_MULTI;
2008         __be32 xkey = htonl(l->key);
2009         struct fib_alias *fa;
2010         int i, s_i;
2011 
2012         if (filter->filter_set)
2013                 flags |= NLM_F_DUMP_FILTERED;
2014 
2015         s_i = cb->args[4];
2016         i = 0;
2017 
2018         /* rcu_read_lock is hold by caller */
2019         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2020                 int err;
2021 
2022                 if (i < s_i)
2023                         goto next;
2024 
2025                 if (tb->tb_id != fa->tb_id)
2026                         goto next;
2027 
2028                 if (filter->filter_set) {
2029                         if (filter->rt_type && fa->fa_type != filter->rt_type)
2030                                 goto next;
2031 
2032                         if ((filter->protocol &&
2033                              fa->fa_info->fib_protocol != filter->protocol))
2034                                 goto next;
2035 
2036                         if (filter->dev &&
2037                             !fib_info_nh_uses_dev(fa->fa_info, filter->dev))
2038                                 goto next;
2039                 }
2040 
2041                 err = fib_dump_info(skb, NETLINK_CB(cb->skb).portid,
2042                                     cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2043                                     tb->tb_id, fa->fa_type,
2044                                     xkey, KEYLENGTH - fa->fa_slen,
2045                                     fa->fa_tos, fa->fa_info, flags);
2046                 if (err < 0) {
2047                         cb->args[4] = i;
2048                         return err;
2049                 }
2050 next:
2051                 i++;
2052         }
2053 
2054         cb->args[4] = i;
2055         return skb->len;
2056 }
2057 
2058 /* rcu_read_lock needs to be hold by caller from readside */
2059 int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
2060                    struct netlink_callback *cb, struct fib_dump_filter *filter)
2061 {
2062         struct trie *t = (struct trie *)tb->tb_data;
2063         struct key_vector *l, *tp = t->kv;
2064         /* Dump starting at last key.
2065          * Note: 0.0.0.0/0 (ie default) is first key.
2066          */
2067         int count = cb->args[2];
2068         t_key key = cb->args[3];
2069 
2070         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
2071                 int err;
2072 
2073                 err = fn_trie_dump_leaf(l, tb, skb, cb, filter);
2074                 if (err < 0) {
2075                         cb->args[3] = key;
2076                         cb->args[2] = count;
2077                         return err;
2078                 }
2079 
2080                 ++count;
2081                 key = l->key + 1;
2082 
2083                 memset(&cb->args[4], 0,
2084                        sizeof(cb->args) - 4*sizeof(cb->args[0]));
2085 
2086                 /* stop loop if key wrapped back to 0 */
2087                 if (key < l->key)
2088                         break;
2089         }
2090 
2091         cb->args[3] = key;
2092         cb->args[2] = count;
2093 
2094         return skb->len;
2095 }
2096 
2097 void __init fib_trie_init(void)
2098 {
2099         fn_alias_kmem = kmem_cache_create("ip_fib_alias",
2100                                           sizeof(struct fib_alias),
2101                                           0, SLAB_PANIC, NULL);
2102 
2103         trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
2104                                            LEAF_SIZE,
2105                                            0, SLAB_PANIC, NULL);
2106 }
2107 
2108 struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
2109 {
2110         struct fib_table *tb;
2111         struct trie *t;
2112         size_t sz = sizeof(*tb);
2113 
2114         if (!alias)
2115                 sz += sizeof(struct trie);
2116 
2117         tb = kzalloc(sz, GFP_KERNEL);
2118         if (!tb)
2119                 return NULL;
2120 
2121         tb->tb_id = id;
2122         tb->tb_num_default = 0;
2123         tb->tb_data = (alias ? alias->__data : tb->__data);
2124 
2125         if (alias)
2126                 return tb;
2127 
2128         t = (struct trie *) tb->tb_data;
2129         t->kv[0].pos = KEYLENGTH;
2130         t->kv[0].slen = KEYLENGTH;
2131 #ifdef CONFIG_IP_FIB_TRIE_STATS
2132         t->stats = alloc_percpu(struct trie_use_stats);
2133         if (!t->stats) {
2134                 kfree(tb);
2135                 tb = NULL;
2136         }
2137 #endif
2138 
2139         return tb;
2140 }
2141 
2142 #ifdef CONFIG_PROC_FS
2143 /* Depth first Trie walk iterator */
2144 struct fib_trie_iter {
2145         struct seq_net_private p;
2146         struct fib_table *tb;
2147         struct key_vector *tnode;
2148         unsigned int index;
2149         unsigned int depth;
2150 };
2151 
2152 static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
2153 {
2154         unsigned long cindex = iter->index;
2155         struct key_vector *pn = iter->tnode;
2156         t_key pkey;
2157 
2158         pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
2159                  iter->tnode, iter->index, iter->depth);
2160 
2161         while (!IS_TRIE(pn)) {
2162                 while (cindex < child_length(pn)) {
2163                         struct key_vector *n = get_child_rcu(pn, cindex++);
2164 
2165                         if (!n)
2166                                 continue;
2167 
2168                         if (IS_LEAF(n)) {
2169                                 iter->tnode = pn;
2170                                 iter->index = cindex;
2171                         } else {
2172                                 /* push down one level */
2173                                 iter->tnode = n;
2174                                 iter->index = 0;
2175                                 ++iter->depth;
2176                         }
2177 
2178                         return n;
2179                 }
2180 
2181                 /* Current node exhausted, pop back up */
2182                 pkey = pn->key;
2183                 pn = node_parent_rcu(pn);
2184                 cindex = get_index(pkey, pn) + 1;
2185                 --iter->depth;
2186         }
2187 
2188         /* record root node so further searches know we are done */
2189         iter->tnode = pn;
2190         iter->index = 0;
2191 
2192         return NULL;
2193 }
2194 
2195 static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
2196                                              struct trie *t)
2197 {
2198         struct key_vector *n, *pn;
2199 
2200         if (!t)
2201                 return NULL;
2202 
2203         pn = t->kv;
2204         n = rcu_dereference(pn->tnode[0]);
2205         if (!n)
2206                 return NULL;
2207 
2208         if (IS_TNODE(n)) {
2209                 iter->tnode = n;
2210                 iter->index = 0;
2211                 iter->depth = 1;
2212         } else {
2213                 iter->tnode = pn;
2214                 iter->index = 0;
2215                 iter->depth = 0;
2216         }
2217 
2218         return n;
2219 }
2220 
2221 static void trie_collect_stats(struct trie *t, struct trie_stat *s)
2222 {
2223         struct key_vector *n;
2224         struct fib_trie_iter iter;
2225 
2226         memset(s, 0, sizeof(*s));
2227 
2228         rcu_read_lock();
2229         for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
2230                 if (IS_LEAF(n)) {
2231                         struct fib_alias *fa;
2232 
2233                         s->leaves++;
2234                         s->totdepth += iter.depth;
2235                         if (iter.depth > s->maxdepth)
2236                                 s->maxdepth = iter.depth;
2237 
2238                         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list)
2239                                 ++s->prefixes;
2240                 } else {
2241                         s->tnodes++;
2242                         if (n->bits < MAX_STAT_DEPTH)
2243                                 s->nodesizes[n->bits]++;
2244                         s->nullpointers += tn_info(n)->empty_children;
2245                 }
2246         }
2247         rcu_read_unlock();
2248 }
2249 
2250 /*
2251  *      This outputs /proc/net/fib_triestats
2252  */
2253 static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
2254 {
2255         unsigned int i, max, pointers, bytes, avdepth;
2256 
2257         if (stat->leaves)
2258                 avdepth = stat->totdepth*100 / stat->leaves;
2259         else
2260                 avdepth = 0;
2261 
2262         seq_printf(seq, "\tAver depth:     %u.%02d\n",
2263                    avdepth / 100, avdepth % 100);
2264         seq_printf(seq, "\tMax depth:      %u\n", stat->maxdepth);
2265 
2266         seq_printf(seq, "\tLeaves:         %u\n", stat->leaves);
2267         bytes = LEAF_SIZE * stat->leaves;
2268 
2269         seq_printf(seq, "\tPrefixes:       %u\n", stat->prefixes);
2270         bytes += sizeof(struct fib_alias) * stat->prefixes;
2271 
2272         seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
2273         bytes += TNODE_SIZE(0) * stat->tnodes;
2274 
2275         max = MAX_STAT_DEPTH;
2276         while (max > 0 && stat->nodesizes[max-1] == 0)
2277                 max--;
2278 
2279         pointers = 0;
2280         for (i = 1; i < max; i++)
2281                 if (stat->nodesizes[i] != 0) {
2282                         seq_printf(seq, "  %u: %u",  i, stat->nodesizes[i]);
2283                         pointers += (1<<i) * stat->nodesizes[i];
2284                 }
2285         seq_putc(seq, '\n');
2286         seq_printf(seq, "\tPointers: %u\n", pointers);
2287 
2288         bytes += sizeof(struct key_vector *) * pointers;
2289         seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
2290         seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
2291 }
2292 
2293 #ifdef CONFIG_IP_FIB_TRIE_STATS
2294 static void trie_show_usage(struct seq_file *seq,
2295                             const struct trie_use_stats __percpu *stats)
2296 {
2297         struct trie_use_stats s = { 0 };
2298         int cpu;
2299 
2300         /* loop through all of the CPUs and gather up the stats */
2301         for_each_possible_cpu(cpu) {
2302                 const struct trie_use_stats *pcpu = per_cpu_ptr(stats, cpu);
2303 
2304                 s.gets += pcpu->gets;
2305                 s.backtrack += pcpu->backtrack;
2306                 s.semantic_match_passed += pcpu->semantic_match_passed;
2307                 s.semantic_match_miss += pcpu->semantic_match_miss;
2308                 s.null_node_hit += pcpu->null_node_hit;
2309                 s.resize_node_skipped += pcpu->resize_node_skipped;
2310         }
2311 
2312         seq_printf(seq, "\nCounters:\n---------\n");
2313         seq_printf(seq, "gets = %u\n", s.gets);
2314         seq_printf(seq, "backtracks = %u\n", s.backtrack);
2315         seq_printf(seq, "semantic match passed = %u\n",
2316                    s.semantic_match_passed);
2317         seq_printf(seq, "semantic match miss = %u\n", s.semantic_match_miss);
2318         seq_printf(seq, "null node hit= %u\n", s.null_node_hit);
2319         seq_printf(seq, "skipped node resize = %u\n\n", s.resize_node_skipped);
2320 }
2321 #endif /*  CONFIG_IP_FIB_TRIE_STATS */
2322 
2323 static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
2324 {
2325         if (tb->tb_id == RT_TABLE_LOCAL)
2326                 seq_puts(seq, "Local:\n");
2327         else if (tb->tb_id == RT_TABLE_MAIN)
2328                 seq_puts(seq, "Main:\n");
2329         else
2330                 seq_printf(seq, "Id %d:\n", tb->tb_id);
2331 }
2332 
2333 
2334 static int fib_triestat_seq_show(struct seq_file *seq, void *v)
2335 {
2336         struct net *net = (struct net *)seq->private;
2337         unsigned int h;
2338 
2339         seq_printf(seq,
2340                    "Basic info: size of leaf:"
2341                    " %zd bytes, size of tnode: %zd bytes.\n",
2342                    LEAF_SIZE, TNODE_SIZE(0));
2343 
2344         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2345                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2346                 struct fib_table *tb;
2347 
2348                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2349                         struct trie *t = (struct trie *) tb->tb_data;
2350                         struct trie_stat stat;
2351 
2352                         if (!t)
2353                                 continue;
2354 
2355                         fib_table_print(seq, tb);
2356 
2357                         trie_collect_stats(t, &stat);
2358                         trie_show_stats(seq, &stat);
2359 #ifdef CONFIG_IP_FIB_TRIE_STATS
2360                         trie_show_usage(seq, t->stats);
2361 #endif
2362                 }
2363         }
2364 
2365         return 0;
2366 }
2367 
2368 static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
2369 {
2370         struct fib_trie_iter *iter = seq->private;
2371         struct net *net = seq_file_net(seq);
2372         loff_t idx = 0;
2373         unsigned int h;
2374 
2375         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2376                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2377                 struct fib_table *tb;
2378 
2379                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2380                         struct key_vector *n;
2381 
2382                         for (n = fib_trie_get_first(iter,
2383                                                     (struct trie *) tb->tb_data);
2384                              n; n = fib_trie_get_next(iter))
2385                                 if (pos == idx++) {
2386                                         iter->tb = tb;
2387                                         return n;
2388                                 }
2389                 }
2390         }
2391 
2392         return NULL;
2393 }
2394 
2395 static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
2396         __acquires(RCU)
2397 {
2398         rcu_read_lock();
2399         return fib_trie_get_idx(seq, *pos);
2400 }
2401 
2402 static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2403 {
2404         struct fib_trie_iter *iter = seq->private;
2405         struct net *net = seq_file_net(seq);
2406         struct fib_table *tb = iter->tb;
2407         struct hlist_node *tb_node;
2408         unsigned int h;
2409         struct key_vector *n;
2410 
2411         ++*pos;
2412         /* next node in same table */
2413         n = fib_trie_get_next(iter);
2414         if (n)
2415                 return n;
2416 
2417         /* walk rest of this hash chain */
2418         h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
2419         while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
2420                 tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
2421                 n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2422                 if (n)
2423                         goto found;
2424         }
2425 
2426         /* new hash chain */
2427         while (++h < FIB_TABLE_HASHSZ) {
2428                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2429                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2430                         n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2431                         if (n)
2432                                 goto found;
2433                 }
2434         }
2435         return NULL;
2436 
2437 found:
2438         iter->tb = tb;
2439         return n;
2440 }
2441 
2442 static void fib_trie_seq_stop(struct seq_file *seq, void *v)
2443         __releases(RCU)
2444 {
2445         rcu_read_unlock();
2446 }
2447 
2448 static void seq_indent(struct seq_file *seq, int n)
2449 {
2450         while (n-- > 0)
2451                 seq_puts(seq, "   ");
2452 }
2453 
2454 static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
2455 {
2456         switch (s) {
2457         case RT_SCOPE_UNIVERSE: return "universe";
2458         case RT_SCOPE_SITE:     return "site";
2459         case RT_SCOPE_LINK:     return "link";
2460         case RT_SCOPE_HOST:     return "host";
2461         case RT_SCOPE_NOWHERE:  return "nowhere";
2462         default:
2463                 snprintf(buf, len, "scope=%d", s);
2464                 return buf;
2465         }
2466 }
2467 
2468 static const char *const rtn_type_names[__RTN_MAX] = {
2469         [RTN_UNSPEC] = "UNSPEC",
2470         [RTN_UNICAST] = "UNICAST",
2471         [RTN_LOCAL] = "LOCAL",
2472         [RTN_BROADCAST] = "BROADCAST",
2473         [RTN_ANYCAST] = "ANYCAST",
2474         [RTN_MULTICAST] = "MULTICAST",
2475         [RTN_BLACKHOLE] = "BLACKHOLE",
2476         [RTN_UNREACHABLE] = "UNREACHABLE",
2477         [RTN_PROHIBIT] = "PROHIBIT",
2478         [RTN_THROW] = "THROW",
2479         [RTN_NAT] = "NAT",
2480         [RTN_XRESOLVE] = "XRESOLVE",
2481 };
2482 
2483 static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
2484 {
2485         if (t < __RTN_MAX && rtn_type_names[t])
2486                 return rtn_type_names[t];
2487         snprintf(buf, len, "type %u", t);
2488         return buf;
2489 }
2490 
2491 /* Pretty print the trie */
2492 static int fib_trie_seq_show(struct seq_file *seq, void *v)
2493 {
2494         const struct fib_trie_iter *iter = seq->private;
2495         struct key_vector *n = v;
2496 
2497         if (IS_TRIE(node_parent_rcu(n)))
2498                 fib_table_print(seq, iter->tb);
2499 
2500         if (IS_TNODE(n)) {
2501                 __be32 prf = htonl(n->key);
2502 
2503                 seq_indent(seq, iter->depth-1);
2504                 seq_printf(seq, "  +-- %pI4/%zu %u %u %u\n",
2505                            &prf, KEYLENGTH - n->pos - n->bits, n->bits,
2506                            tn_info(n)->full_children,
2507                            tn_info(n)->empty_children);
2508         } else {
2509                 __be32 val = htonl(n->key);
2510                 struct fib_alias *fa;
2511 
2512                 seq_indent(seq, iter->depth);
2513                 seq_printf(seq, "  |-- %pI4\n", &val);
2514 
2515                 hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
2516                         char buf1[32], buf2[32];
2517 
2518                         seq_indent(seq, iter->depth + 1);
2519                         seq_printf(seq, "  /%zu %s %s",
2520                                    KEYLENGTH - fa->fa_slen,
2521                                    rtn_scope(buf1, sizeof(buf1),
2522                                              fa->fa_info->fib_scope),
2523                                    rtn_type(buf2, sizeof(buf2),
2524                                             fa->fa_type));
2525                         if (fa->fa_tos)
2526                                 seq_printf(seq, " tos=%d", fa->fa_tos);
2527                         seq_putc(seq, '\n');
2528                 }
2529         }
2530 
2531         return 0;
2532 }
2533 
2534 static const struct seq_operations fib_trie_seq_ops = {
2535         .start  = fib_trie_seq_start,
2536         .next   = fib_trie_seq_next,
2537         .stop   = fib_trie_seq_stop,
2538         .show   = fib_trie_seq_show,
2539 };
2540 
2541 struct fib_route_iter {
2542         struct seq_net_private p;
2543         struct fib_table *main_tb;
2544         struct key_vector *tnode;
2545         loff_t  pos;
2546         t_key   key;
2547 };
2548 
2549 static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
2550                                             loff_t pos)
2551 {
2552         struct key_vector *l, **tp = &iter->tnode;
2553         t_key key;
2554 
2555         /* use cached location of previously found key */
2556         if (iter->pos > 0 && pos >= iter->pos) {
2557                 key = iter->key;
2558         } else {
2559                 iter->pos = 1;
2560                 key = 0;
2561         }
2562 
2563         pos -= iter->pos;
2564 
2565         while ((l = leaf_walk_rcu(tp, key)) && (pos-- > 0)) {
2566                 key = l->key + 1;
2567                 iter->pos++;
2568                 l = NULL;
2569 
2570                 /* handle unlikely case of a key wrap */
2571                 if (!key)
2572                         break;
2573         }
2574 
2575         if (l)
2576                 iter->key = l->key;     /* remember it */
2577         else
2578                 iter->pos = 0;          /* forget it */
2579 
2580         return l;
2581 }
2582 
2583 static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
2584         __acquires(RCU)
2585 {
2586         struct fib_route_iter *iter = seq->private;
2587         struct fib_table *tb;
2588         struct trie *t;
2589 
2590         rcu_read_lock();
2591 
2592         tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
2593         if (!tb)
2594                 return NULL;
2595 
2596         iter->main_tb = tb;
2597         t = (struct trie *)tb->tb_data;
2598         iter->tnode = t->kv;
2599 
2600         if (*pos != 0)
2601                 return fib_route_get_idx(iter, *pos);
2602 
2603         iter->pos = 0;
2604         iter->key = KEY_MAX;
2605 
2606         return SEQ_START_TOKEN;
2607 }
2608 
2609 static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2610 {
2611         struct fib_route_iter *iter = seq->private;
2612         struct key_vector *l = NULL;
2613         t_key key = iter->key + 1;
2614 
2615         ++*pos;
2616 
2617         /* only allow key of 0 for start of sequence */
2618         if ((v == SEQ_START_TOKEN) || key)
2619                 l = leaf_walk_rcu(&iter->tnode, key);
2620 
2621         if (l) {
2622                 iter->key = l->key;
2623                 iter->pos++;
2624         } else {
2625                 iter->pos = 0;
2626         }
2627 
2628         return l;
2629 }
2630 
2631 static void fib_route_seq_stop(struct seq_file *seq, void *v)
2632         __releases(RCU)
2633 {
2634         rcu_read_unlock();
2635 }
2636 
2637 static unsigned int fib_flag_trans(int type, __be32 mask, const struct fib_info *fi)
2638 {
2639         unsigned int flags = 0;
2640 
2641         if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
2642                 flags = RTF_REJECT;
2643         if (fi && fi->fib_nh->fib_nh_gw4)
2644                 flags |= RTF_GATEWAY;
2645         if (mask == htonl(0xFFFFFFFF))
2646                 flags |= RTF_HOST;
2647         flags |= RTF_UP;
2648         return flags;
2649 }
2650 
2651 /*
2652  *      This outputs /proc/net/route.
2653  *      The format of the file is not supposed to be changed
2654  *      and needs to be same as fib_hash output to avoid breaking
2655  *      legacy utilities
2656  */
2657 static int fib_route_seq_show(struct seq_file *seq, void *v)
2658 {
2659         struct fib_route_iter *iter = seq->private;
2660         struct fib_table *tb = iter->main_tb;
2661         struct fib_alias *fa;
2662         struct key_vector *l = v;
2663         __be32 prefix;
2664 
2665         if (v == SEQ_START_TOKEN) {
2666                 seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
2667                            "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
2668                            "\tWindow\tIRTT");
2669                 return 0;
2670         }
2671 
2672         prefix = htonl(l->key);
2673 
2674         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2675                 const struct fib_info *fi = fa->fa_info;
2676                 __be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
2677                 unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
2678 
2679                 if ((fa->fa_type == RTN_BROADCAST) ||
2680                     (fa->fa_type == RTN_MULTICAST))
2681                         continue;
2682 
2683                 if (fa->tb_id != tb->tb_id)
2684                         continue;
2685 
2686                 seq_setwidth(seq, 127);
2687 
2688                 if (fi)
2689                         seq_printf(seq,
2690                                    "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
2691                                    "%d\t%08X\t%d\t%u\t%u",
2692                                    fi->fib_dev ? fi->fib_dev->name : "*",
2693                                    prefix,
2694                                    fi->fib_nh->fib_nh_gw4, flags, 0, 0,
2695                                    fi->fib_priority,
2696                                    mask,
2697                                    (fi->fib_advmss ?
2698                                     fi->fib_advmss + 40 : 0),
2699                                    fi->fib_window,
2700                                    fi->fib_rtt >> 3);
2701                 else
2702                         seq_printf(seq,
2703                                    "*\t%08X\t%08X\t%04X\t%d\t%u\t"
2704                                    "%d\t%08X\t%d\t%u\t%u",
2705                                    prefix, 0, flags, 0, 0, 0,
2706                                    mask, 0, 0, 0);
2707 
2708                 seq_pad(seq, '\n');
2709         }
2710 
2711         return 0;
2712 }
2713 
2714 static const struct seq_operations fib_route_seq_ops = {
2715         .start  = fib_route_seq_start,
2716         .next   = fib_route_seq_next,
2717         .stop   = fib_route_seq_stop,
2718         .show   = fib_route_seq_show,
2719 };
2720 
2721 int __net_init fib_proc_init(struct net *net)
2722 {
2723         if (!proc_create_net("fib_trie", 0444, net->proc_net, &fib_trie_seq_ops,
2724                         sizeof(struct fib_trie_iter)))
2725                 goto out1;
2726 
2727         if (!proc_create_net_single("fib_triestat", 0444, net->proc_net,
2728                         fib_triestat_seq_show, NULL))
2729                 goto out2;
2730 
2731         if (!proc_create_net("route", 0444, net->proc_net, &fib_route_seq_ops,
2732                         sizeof(struct fib_route_iter)))
2733                 goto out3;
2734 
2735         return 0;
2736 
2737 out3:
2738         remove_proc_entry("fib_triestat", net->proc_net);
2739 out2:
2740         remove_proc_entry("fib_trie", net->proc_net);
2741 out1:
2742         return -ENOMEM;
2743 }
2744 
2745 void __net_exit fib_proc_exit(struct net *net)
2746 {
2747         remove_proc_entry("fib_trie", net->proc_net);
2748         remove_proc_entry("fib_triestat", net->proc_net);
2749         remove_proc_entry("route", net->proc_net);
2750 }
2751 
2752 #endif /* CONFIG_PROC_FS */
2753 

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