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Linux/net/ipv4/fib_trie.c

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  1 /*
  2  *   This program is free software; you can redistribute it and/or
  3  *   modify it under the terms of the GNU General Public License
  4  *   as published by the Free Software Foundation; either version
  5  *   2 of the License, or (at your option) any later version.
  6  *
  7  *   Robert Olsson <robert.olsson@its.uu.se> Uppsala Universitet
  8  *     & Swedish University of Agricultural Sciences.
  9  *
 10  *   Jens Laas <jens.laas@data.slu.se> Swedish University of
 11  *     Agricultural Sciences.
 12  *
 13  *   Hans Liss <hans.liss@its.uu.se>  Uppsala Universitet
 14  *
 15  * This work is based on the LPC-trie which is originally described in:
 16  *
 17  * An experimental study of compression methods for dynamic tries
 18  * Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
 19  * http://www.csc.kth.se/~snilsson/software/dyntrie2/
 20  *
 21  *
 22  * IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
 23  * IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
 24  *
 25  *
 26  * Code from fib_hash has been reused which includes the following header:
 27  *
 28  *
 29  * INET         An implementation of the TCP/IP protocol suite for the LINUX
 30  *              operating system.  INET is implemented using the  BSD Socket
 31  *              interface as the means of communication with the user level.
 32  *
 33  *              IPv4 FIB: lookup engine and maintenance routines.
 34  *
 35  *
 36  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 37  *
 38  *              This program is free software; you can redistribute it and/or
 39  *              modify it under the terms of the GNU General Public License
 40  *              as published by the Free Software Foundation; either version
 41  *              2 of the License, or (at your option) any later version.
 42  *
 43  * Substantial contributions to this work comes from:
 44  *
 45  *              David S. Miller, <davem@davemloft.net>
 46  *              Stephen Hemminger <shemminger@osdl.org>
 47  *              Paul E. McKenney <paulmck@us.ibm.com>
 48  *              Patrick McHardy <kaber@trash.net>
 49  */
 50 
 51 #define VERSION "0.409"
 52 
 53 #include <linux/cache.h>
 54 #include <linux/uaccess.h>
 55 #include <linux/bitops.h>
 56 #include <linux/types.h>
 57 #include <linux/kernel.h>
 58 #include <linux/mm.h>
 59 #include <linux/string.h>
 60 #include <linux/socket.h>
 61 #include <linux/sockios.h>
 62 #include <linux/errno.h>
 63 #include <linux/in.h>
 64 #include <linux/inet.h>
 65 #include <linux/inetdevice.h>
 66 #include <linux/netdevice.h>
 67 #include <linux/if_arp.h>
 68 #include <linux/proc_fs.h>
 69 #include <linux/rcupdate.h>
 70 #include <linux/skbuff.h>
 71 #include <linux/netlink.h>
 72 #include <linux/init.h>
 73 #include <linux/list.h>
 74 #include <linux/slab.h>
 75 #include <linux/export.h>
 76 #include <linux/vmalloc.h>
 77 #include <linux/notifier.h>
 78 #include <net/net_namespace.h>
 79 #include <net/ip.h>
 80 #include <net/protocol.h>
 81 #include <net/route.h>
 82 #include <net/tcp.h>
 83 #include <net/sock.h>
 84 #include <net/ip_fib.h>
 85 #include <net/fib_notifier.h>
 86 #include <trace/events/fib.h>
 87 #include "fib_lookup.h"
 88 
 89 static int call_fib_entry_notifier(struct notifier_block *nb, struct net *net,
 90                                    enum fib_event_type event_type, u32 dst,
 91                                    int dst_len, struct fib_alias *fa)
 92 {
 93         struct fib_entry_notifier_info info = {
 94                 .dst = dst,
 95                 .dst_len = dst_len,
 96                 .fi = fa->fa_info,
 97                 .tos = fa->fa_tos,
 98                 .type = fa->fa_type,
 99                 .tb_id = fa->tb_id,
100         };
101         return call_fib4_notifier(nb, net, event_type, &info.info);
102 }
103 
104 static int call_fib_entry_notifiers(struct net *net,
105                                     enum fib_event_type event_type, u32 dst,
106                                     int dst_len, struct fib_alias *fa,
107                                     struct netlink_ext_ack *extack)
108 {
109         struct fib_entry_notifier_info info = {
110                 .info.extack = extack,
111                 .dst = dst,
112                 .dst_len = dst_len,
113                 .fi = fa->fa_info,
114                 .tos = fa->fa_tos,
115                 .type = fa->fa_type,
116                 .tb_id = fa->tb_id,
117         };
118         return call_fib4_notifiers(net, event_type, &info.info);
119 }
120 
121 #define MAX_STAT_DEPTH 32
122 
123 #define KEYLENGTH       (8*sizeof(t_key))
124 #define KEY_MAX         ((t_key)~0)
125 
126 typedef unsigned int t_key;
127 
128 #define IS_TRIE(n)      ((n)->pos >= KEYLENGTH)
129 #define IS_TNODE(n)     ((n)->bits)
130 #define IS_LEAF(n)      (!(n)->bits)
131 
132 struct key_vector {
133         t_key key;
134         unsigned char pos;              /* 2log(KEYLENGTH) bits needed */
135         unsigned char bits;             /* 2log(KEYLENGTH) bits needed */
136         unsigned char slen;
137         union {
138                 /* This list pointer if valid if (pos | bits) == 0 (LEAF) */
139                 struct hlist_head leaf;
140                 /* This array is valid if (pos | bits) > 0 (TNODE) */
141                 struct key_vector __rcu *tnode[0];
142         };
143 };
144 
145 struct tnode {
146         struct rcu_head rcu;
147         t_key empty_children;           /* KEYLENGTH bits needed */
148         t_key full_children;            /* KEYLENGTH bits needed */
149         struct key_vector __rcu *parent;
150         struct key_vector kv[1];
151 #define tn_bits kv[0].bits
152 };
153 
154 #define TNODE_SIZE(n)   offsetof(struct tnode, kv[0].tnode[n])
155 #define LEAF_SIZE       TNODE_SIZE(1)
156 
157 #ifdef CONFIG_IP_FIB_TRIE_STATS
158 struct trie_use_stats {
159         unsigned int gets;
160         unsigned int backtrack;
161         unsigned int semantic_match_passed;
162         unsigned int semantic_match_miss;
163         unsigned int null_node_hit;
164         unsigned int resize_node_skipped;
165 };
166 #endif
167 
168 struct trie_stat {
169         unsigned int totdepth;
170         unsigned int maxdepth;
171         unsigned int tnodes;
172         unsigned int leaves;
173         unsigned int nullpointers;
174         unsigned int prefixes;
175         unsigned int nodesizes[MAX_STAT_DEPTH];
176 };
177 
178 struct trie {
179         struct key_vector kv[1];
180 #ifdef CONFIG_IP_FIB_TRIE_STATS
181         struct trie_use_stats __percpu *stats;
182 #endif
183 };
184 
185 static struct key_vector *resize(struct trie *t, struct key_vector *tn);
186 static size_t tnode_free_size;
187 
188 /*
189  * synchronize_rcu after call_rcu for that many pages; it should be especially
190  * useful before resizing the root node with PREEMPT_NONE configs; the value was
191  * obtained experimentally, aiming to avoid visible slowdown.
192  */
193 static const int sync_pages = 128;
194 
195 static struct kmem_cache *fn_alias_kmem __ro_after_init;
196 static struct kmem_cache *trie_leaf_kmem __ro_after_init;
197 
198 static inline struct tnode *tn_info(struct key_vector *kv)
199 {
200         return container_of(kv, struct tnode, kv[0]);
201 }
202 
203 /* caller must hold RTNL */
204 #define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
205 #define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
206 
207 /* caller must hold RCU read lock or RTNL */
208 #define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
209 #define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
210 
211 /* wrapper for rcu_assign_pointer */
212 static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
213 {
214         if (n)
215                 rcu_assign_pointer(tn_info(n)->parent, tp);
216 }
217 
218 #define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(n)->parent, p)
219 
220 /* This provides us with the number of children in this node, in the case of a
221  * leaf this will return 0 meaning none of the children are accessible.
222  */
223 static inline unsigned long child_length(const struct key_vector *tn)
224 {
225         return (1ul << tn->bits) & ~(1ul);
226 }
227 
228 #define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
229 
230 static inline unsigned long get_index(t_key key, struct key_vector *kv)
231 {
232         unsigned long index = key ^ kv->key;
233 
234         if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
235                 return 0;
236 
237         return index >> kv->pos;
238 }
239 
240 /* To understand this stuff, an understanding of keys and all their bits is
241  * necessary. Every node in the trie has a key associated with it, but not
242  * all of the bits in that key are significant.
243  *
244  * Consider a node 'n' and its parent 'tp'.
245  *
246  * If n is a leaf, every bit in its key is significant. Its presence is
247  * necessitated by path compression, since during a tree traversal (when
248  * searching for a leaf - unless we are doing an insertion) we will completely
249  * ignore all skipped bits we encounter. Thus we need to verify, at the end of
250  * a potentially successful search, that we have indeed been walking the
251  * correct key path.
252  *
253  * Note that we can never "miss" the correct key in the tree if present by
254  * following the wrong path. Path compression ensures that segments of the key
255  * that are the same for all keys with a given prefix are skipped, but the
256  * skipped part *is* identical for each node in the subtrie below the skipped
257  * bit! trie_insert() in this implementation takes care of that.
258  *
259  * if n is an internal node - a 'tnode' here, the various parts of its key
260  * have many different meanings.
261  *
262  * Example:
263  * _________________________________________________________________
264  * | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
265  * -----------------------------------------------------------------
266  *  31  30  29  28  27  26  25  24  23  22  21  20  19  18  17  16
267  *
268  * _________________________________________________________________
269  * | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
270  * -----------------------------------------------------------------
271  *  15  14  13  12  11  10   9   8   7   6   5   4   3   2   1   0
272  *
273  * tp->pos = 22
274  * tp->bits = 3
275  * n->pos = 13
276  * n->bits = 4
277  *
278  * First, let's just ignore the bits that come before the parent tp, that is
279  * the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
280  * point we do not use them for anything.
281  *
282  * The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
283  * index into the parent's child array. That is, they will be used to find
284  * 'n' among tp's children.
285  *
286  * The bits from (n->pos + n->bits) to (tp->pos - 1) - "S" - are skipped bits
287  * for the node n.
288  *
289  * All the bits we have seen so far are significant to the node n. The rest
290  * of the bits are really not needed or indeed known in n->key.
291  *
292  * The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
293  * n's child array, and will of course be different for each child.
294  *
295  * The rest of the bits, from 0 to (n->pos -1) - "u" - are completely unknown
296  * at this point.
297  */
298 
299 static const int halve_threshold = 25;
300 static const int inflate_threshold = 50;
301 static const int halve_threshold_root = 15;
302 static const int inflate_threshold_root = 30;
303 
304 static void __alias_free_mem(struct rcu_head *head)
305 {
306         struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
307         kmem_cache_free(fn_alias_kmem, fa);
308 }
309 
310 static inline void alias_free_mem_rcu(struct fib_alias *fa)
311 {
312         call_rcu(&fa->rcu, __alias_free_mem);
313 }
314 
315 #define TNODE_KMALLOC_MAX \
316         ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct key_vector *))
317 #define TNODE_VMALLOC_MAX \
318         ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
319 
320 static void __node_free_rcu(struct rcu_head *head)
321 {
322         struct tnode *n = container_of(head, struct tnode, rcu);
323 
324         if (!n->tn_bits)
325                 kmem_cache_free(trie_leaf_kmem, n);
326         else
327                 kvfree(n);
328 }
329 
330 #define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
331 
332 static struct tnode *tnode_alloc(int bits)
333 {
334         size_t size;
335 
336         /* verify bits is within bounds */
337         if (bits > TNODE_VMALLOC_MAX)
338                 return NULL;
339 
340         /* determine size and verify it is non-zero and didn't overflow */
341         size = TNODE_SIZE(1ul << bits);
342 
343         if (size <= PAGE_SIZE)
344                 return kzalloc(size, GFP_KERNEL);
345         else
346                 return vzalloc(size);
347 }
348 
349 static inline void empty_child_inc(struct key_vector *n)
350 {
351         ++tn_info(n)->empty_children ? : ++tn_info(n)->full_children;
352 }
353 
354 static inline void empty_child_dec(struct key_vector *n)
355 {
356         tn_info(n)->empty_children-- ? : tn_info(n)->full_children--;
357 }
358 
359 static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
360 {
361         struct key_vector *l;
362         struct tnode *kv;
363 
364         kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
365         if (!kv)
366                 return NULL;
367 
368         /* initialize key vector */
369         l = kv->kv;
370         l->key = key;
371         l->pos = 0;
372         l->bits = 0;
373         l->slen = fa->fa_slen;
374 
375         /* link leaf to fib alias */
376         INIT_HLIST_HEAD(&l->leaf);
377         hlist_add_head(&fa->fa_list, &l->leaf);
378 
379         return l;
380 }
381 
382 static struct key_vector *tnode_new(t_key key, int pos, int bits)
383 {
384         unsigned int shift = pos + bits;
385         struct key_vector *tn;
386         struct tnode *tnode;
387 
388         /* verify bits and pos their msb bits clear and values are valid */
389         BUG_ON(!bits || (shift > KEYLENGTH));
390 
391         tnode = tnode_alloc(bits);
392         if (!tnode)
393                 return NULL;
394 
395         pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
396                  sizeof(struct key_vector *) << bits);
397 
398         if (bits == KEYLENGTH)
399                 tnode->full_children = 1;
400         else
401                 tnode->empty_children = 1ul << bits;
402 
403         tn = tnode->kv;
404         tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
405         tn->pos = pos;
406         tn->bits = bits;
407         tn->slen = pos;
408 
409         return tn;
410 }
411 
412 /* Check whether a tnode 'n' is "full", i.e. it is an internal node
413  * and no bits are skipped. See discussion in dyntree paper p. 6
414  */
415 static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
416 {
417         return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
418 }
419 
420 /* Add a child at position i overwriting the old value.
421  * Update the value of full_children and empty_children.
422  */
423 static void put_child(struct key_vector *tn, unsigned long i,
424                       struct key_vector *n)
425 {
426         struct key_vector *chi = get_child(tn, i);
427         int isfull, wasfull;
428 
429         BUG_ON(i >= child_length(tn));
430 
431         /* update emptyChildren, overflow into fullChildren */
432         if (!n && chi)
433                 empty_child_inc(tn);
434         if (n && !chi)
435                 empty_child_dec(tn);
436 
437         /* update fullChildren */
438         wasfull = tnode_full(tn, chi);
439         isfull = tnode_full(tn, n);
440 
441         if (wasfull && !isfull)
442                 tn_info(tn)->full_children--;
443         else if (!wasfull && isfull)
444                 tn_info(tn)->full_children++;
445 
446         if (n && (tn->slen < n->slen))
447                 tn->slen = n->slen;
448 
449         rcu_assign_pointer(tn->tnode[i], n);
450 }
451 
452 static void update_children(struct key_vector *tn)
453 {
454         unsigned long i;
455 
456         /* update all of the child parent pointers */
457         for (i = child_length(tn); i;) {
458                 struct key_vector *inode = get_child(tn, --i);
459 
460                 if (!inode)
461                         continue;
462 
463                 /* Either update the children of a tnode that
464                  * already belongs to us or update the child
465                  * to point to ourselves.
466                  */
467                 if (node_parent(inode) == tn)
468                         update_children(inode);
469                 else
470                         node_set_parent(inode, tn);
471         }
472 }
473 
474 static inline void put_child_root(struct key_vector *tp, t_key key,
475                                   struct key_vector *n)
476 {
477         if (IS_TRIE(tp))
478                 rcu_assign_pointer(tp->tnode[0], n);
479         else
480                 put_child(tp, get_index(key, tp), n);
481 }
482 
483 static inline void tnode_free_init(struct key_vector *tn)
484 {
485         tn_info(tn)->rcu.next = NULL;
486 }
487 
488 static inline void tnode_free_append(struct key_vector *tn,
489                                      struct key_vector *n)
490 {
491         tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
492         tn_info(tn)->rcu.next = &tn_info(n)->rcu;
493 }
494 
495 static void tnode_free(struct key_vector *tn)
496 {
497         struct callback_head *head = &tn_info(tn)->rcu;
498 
499         while (head) {
500                 head = head->next;
501                 tnode_free_size += TNODE_SIZE(1ul << tn->bits);
502                 node_free(tn);
503 
504                 tn = container_of(head, struct tnode, rcu)->kv;
505         }
506 
507         if (tnode_free_size >= PAGE_SIZE * sync_pages) {
508                 tnode_free_size = 0;
509                 synchronize_rcu();
510         }
511 }
512 
513 static struct key_vector *replace(struct trie *t,
514                                   struct key_vector *oldtnode,
515                                   struct key_vector *tn)
516 {
517         struct key_vector *tp = node_parent(oldtnode);
518         unsigned long i;
519 
520         /* setup the parent pointer out of and back into this node */
521         NODE_INIT_PARENT(tn, tp);
522         put_child_root(tp, tn->key, tn);
523 
524         /* update all of the child parent pointers */
525         update_children(tn);
526 
527         /* all pointers should be clean so we are done */
528         tnode_free(oldtnode);
529 
530         /* resize children now that oldtnode is freed */
531         for (i = child_length(tn); i;) {
532                 struct key_vector *inode = get_child(tn, --i);
533 
534                 /* resize child node */
535                 if (tnode_full(tn, inode))
536                         tn = resize(t, inode);
537         }
538 
539         return tp;
540 }
541 
542 static struct key_vector *inflate(struct trie *t,
543                                   struct key_vector *oldtnode)
544 {
545         struct key_vector *tn;
546         unsigned long i;
547         t_key m;
548 
549         pr_debug("In inflate\n");
550 
551         tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
552         if (!tn)
553                 goto notnode;
554 
555         /* prepare oldtnode to be freed */
556         tnode_free_init(oldtnode);
557 
558         /* Assemble all of the pointers in our cluster, in this case that
559          * represents all of the pointers out of our allocated nodes that
560          * point to existing tnodes and the links between our allocated
561          * nodes.
562          */
563         for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
564                 struct key_vector *inode = get_child(oldtnode, --i);
565                 struct key_vector *node0, *node1;
566                 unsigned long j, k;
567 
568                 /* An empty child */
569                 if (!inode)
570                         continue;
571 
572                 /* A leaf or an internal node with skipped bits */
573                 if (!tnode_full(oldtnode, inode)) {
574                         put_child(tn, get_index(inode->key, tn), inode);
575                         continue;
576                 }
577 
578                 /* drop the node in the old tnode free list */
579                 tnode_free_append(oldtnode, inode);
580 
581                 /* An internal node with two children */
582                 if (inode->bits == 1) {
583                         put_child(tn, 2 * i + 1, get_child(inode, 1));
584                         put_child(tn, 2 * i, get_child(inode, 0));
585                         continue;
586                 }
587 
588                 /* We will replace this node 'inode' with two new
589                  * ones, 'node0' and 'node1', each with half of the
590                  * original children. The two new nodes will have
591                  * a position one bit further down the key and this
592                  * means that the "significant" part of their keys
593                  * (see the discussion near the top of this file)
594                  * will differ by one bit, which will be "" in
595                  * node0's key and "1" in node1's key. Since we are
596                  * moving the key position by one step, the bit that
597                  * we are moving away from - the bit at position
598                  * (tn->pos) - is the one that will differ between
599                  * node0 and node1. So... we synthesize that bit in the
600                  * two new keys.
601                  */
602                 node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
603                 if (!node1)
604                         goto nomem;
605                 node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
606 
607                 tnode_free_append(tn, node1);
608                 if (!node0)
609                         goto nomem;
610                 tnode_free_append(tn, node0);
611 
612                 /* populate child pointers in new nodes */
613                 for (k = child_length(inode), j = k / 2; j;) {
614                         put_child(node1, --j, get_child(inode, --k));
615                         put_child(node0, j, get_child(inode, j));
616                         put_child(node1, --j, get_child(inode, --k));
617                         put_child(node0, j, get_child(inode, j));
618                 }
619 
620                 /* link new nodes to parent */
621                 NODE_INIT_PARENT(node1, tn);
622                 NODE_INIT_PARENT(node0, tn);
623 
624                 /* link parent to nodes */
625                 put_child(tn, 2 * i + 1, node1);
626                 put_child(tn, 2 * i, node0);
627         }
628 
629         /* setup the parent pointers into and out of this node */
630         return replace(t, oldtnode, tn);
631 nomem:
632         /* all pointers should be clean so we are done */
633         tnode_free(tn);
634 notnode:
635         return NULL;
636 }
637 
638 static struct key_vector *halve(struct trie *t,
639                                 struct key_vector *oldtnode)
640 {
641         struct key_vector *tn;
642         unsigned long i;
643 
644         pr_debug("In halve\n");
645 
646         tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
647         if (!tn)
648                 goto notnode;
649 
650         /* prepare oldtnode to be freed */
651         tnode_free_init(oldtnode);
652 
653         /* Assemble all of the pointers in our cluster, in this case that
654          * represents all of the pointers out of our allocated nodes that
655          * point to existing tnodes and the links between our allocated
656          * nodes.
657          */
658         for (i = child_length(oldtnode); i;) {
659                 struct key_vector *node1 = get_child(oldtnode, --i);
660                 struct key_vector *node0 = get_child(oldtnode, --i);
661                 struct key_vector *inode;
662 
663                 /* At least one of the children is empty */
664                 if (!node1 || !node0) {
665                         put_child(tn, i / 2, node1 ? : node0);
666                         continue;
667                 }
668 
669                 /* Two nonempty children */
670                 inode = tnode_new(node0->key, oldtnode->pos, 1);
671                 if (!inode)
672                         goto nomem;
673                 tnode_free_append(tn, inode);
674 
675                 /* initialize pointers out of node */
676                 put_child(inode, 1, node1);
677                 put_child(inode, 0, node0);
678                 NODE_INIT_PARENT(inode, tn);
679 
680                 /* link parent to node */
681                 put_child(tn, i / 2, inode);
682         }
683 
684         /* setup the parent pointers into and out of this node */
685         return replace(t, oldtnode, tn);
686 nomem:
687         /* all pointers should be clean so we are done */
688         tnode_free(tn);
689 notnode:
690         return NULL;
691 }
692 
693 static struct key_vector *collapse(struct trie *t,
694                                    struct key_vector *oldtnode)
695 {
696         struct key_vector *n, *tp;
697         unsigned long i;
698 
699         /* scan the tnode looking for that one child that might still exist */
700         for (n = NULL, i = child_length(oldtnode); !n && i;)
701                 n = get_child(oldtnode, --i);
702 
703         /* compress one level */
704         tp = node_parent(oldtnode);
705         put_child_root(tp, oldtnode->key, n);
706         node_set_parent(n, tp);
707 
708         /* drop dead node */
709         node_free(oldtnode);
710 
711         return tp;
712 }
713 
714 static unsigned char update_suffix(struct key_vector *tn)
715 {
716         unsigned char slen = tn->pos;
717         unsigned long stride, i;
718         unsigned char slen_max;
719 
720         /* only vector 0 can have a suffix length greater than or equal to
721          * tn->pos + tn->bits, the second highest node will have a suffix
722          * length at most of tn->pos + tn->bits - 1
723          */
724         slen_max = min_t(unsigned char, tn->pos + tn->bits - 1, tn->slen);
725 
726         /* search though the list of children looking for nodes that might
727          * have a suffix greater than the one we currently have.  This is
728          * why we start with a stride of 2 since a stride of 1 would
729          * represent the nodes with suffix length equal to tn->pos
730          */
731         for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
732                 struct key_vector *n = get_child(tn, i);
733 
734                 if (!n || (n->slen <= slen))
735                         continue;
736 
737                 /* update stride and slen based on new value */
738                 stride <<= (n->slen - slen);
739                 slen = n->slen;
740                 i &= ~(stride - 1);
741 
742                 /* stop searching if we have hit the maximum possible value */
743                 if (slen >= slen_max)
744                         break;
745         }
746 
747         tn->slen = slen;
748 
749         return slen;
750 }
751 
752 /* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
753  * the Helsinki University of Technology and Matti Tikkanen of Nokia
754  * Telecommunications, page 6:
755  * "A node is doubled if the ratio of non-empty children to all
756  * children in the *doubled* node is at least 'high'."
757  *
758  * 'high' in this instance is the variable 'inflate_threshold'. It
759  * is expressed as a percentage, so we multiply it with
760  * child_length() and instead of multiplying by 2 (since the
761  * child array will be doubled by inflate()) and multiplying
762  * the left-hand side by 100 (to handle the percentage thing) we
763  * multiply the left-hand side by 50.
764  *
765  * The left-hand side may look a bit weird: child_length(tn)
766  * - tn->empty_children is of course the number of non-null children
767  * in the current node. tn->full_children is the number of "full"
768  * children, that is non-null tnodes with a skip value of 0.
769  * All of those will be doubled in the resulting inflated tnode, so
770  * we just count them one extra time here.
771  *
772  * A clearer way to write this would be:
773  *
774  * to_be_doubled = tn->full_children;
775  * not_to_be_doubled = child_length(tn) - tn->empty_children -
776  *     tn->full_children;
777  *
778  * new_child_length = child_length(tn) * 2;
779  *
780  * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
781  *      new_child_length;
782  * if (new_fill_factor >= inflate_threshold)
783  *
784  * ...and so on, tho it would mess up the while () loop.
785  *
786  * anyway,
787  * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
788  *      inflate_threshold
789  *
790  * avoid a division:
791  * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
792  *      inflate_threshold * new_child_length
793  *
794  * expand not_to_be_doubled and to_be_doubled, and shorten:
795  * 100 * (child_length(tn) - tn->empty_children +
796  *    tn->full_children) >= inflate_threshold * new_child_length
797  *
798  * expand new_child_length:
799  * 100 * (child_length(tn) - tn->empty_children +
800  *    tn->full_children) >=
801  *      inflate_threshold * child_length(tn) * 2
802  *
803  * shorten again:
804  * 50 * (tn->full_children + child_length(tn) -
805  *    tn->empty_children) >= inflate_threshold *
806  *    child_length(tn)
807  *
808  */
809 static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
810 {
811         unsigned long used = child_length(tn);
812         unsigned long threshold = used;
813 
814         /* Keep root node larger */
815         threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
816         used -= tn_info(tn)->empty_children;
817         used += tn_info(tn)->full_children;
818 
819         /* if bits == KEYLENGTH then pos = 0, and will fail below */
820 
821         return (used > 1) && tn->pos && ((50 * used) >= threshold);
822 }
823 
824 static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
825 {
826         unsigned long used = child_length(tn);
827         unsigned long threshold = used;
828 
829         /* Keep root node larger */
830         threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
831         used -= tn_info(tn)->empty_children;
832 
833         /* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
834 
835         return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
836 }
837 
838 static inline bool should_collapse(struct key_vector *tn)
839 {
840         unsigned long used = child_length(tn);
841 
842         used -= tn_info(tn)->empty_children;
843 
844         /* account for bits == KEYLENGTH case */
845         if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
846                 used -= KEY_MAX;
847 
848         /* One child or none, time to drop us from the trie */
849         return used < 2;
850 }
851 
852 #define MAX_WORK 10
853 static struct key_vector *resize(struct trie *t, struct key_vector *tn)
854 {
855 #ifdef CONFIG_IP_FIB_TRIE_STATS
856         struct trie_use_stats __percpu *stats = t->stats;
857 #endif
858         struct key_vector *tp = node_parent(tn);
859         unsigned long cindex = get_index(tn->key, tp);
860         int max_work = MAX_WORK;
861 
862         pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
863                  tn, inflate_threshold, halve_threshold);
864 
865         /* track the tnode via the pointer from the parent instead of
866          * doing it ourselves.  This way we can let RCU fully do its
867          * thing without us interfering
868          */
869         BUG_ON(tn != get_child(tp, cindex));
870 
871         /* Double as long as the resulting node has a number of
872          * nonempty nodes that are above the threshold.
873          */
874         while (should_inflate(tp, tn) && max_work) {
875                 tp = inflate(t, tn);
876                 if (!tp) {
877 #ifdef CONFIG_IP_FIB_TRIE_STATS
878                         this_cpu_inc(stats->resize_node_skipped);
879 #endif
880                         break;
881                 }
882 
883                 max_work--;
884                 tn = get_child(tp, cindex);
885         }
886 
887         /* update parent in case inflate failed */
888         tp = node_parent(tn);
889 
890         /* Return if at least one inflate is run */
891         if (max_work != MAX_WORK)
892                 return tp;
893 
894         /* Halve as long as the number of empty children in this
895          * node is above threshold.
896          */
897         while (should_halve(tp, tn) && max_work) {
898                 tp = halve(t, tn);
899                 if (!tp) {
900 #ifdef CONFIG_IP_FIB_TRIE_STATS
901                         this_cpu_inc(stats->resize_node_skipped);
902 #endif
903                         break;
904                 }
905 
906                 max_work--;
907                 tn = get_child(tp, cindex);
908         }
909 
910         /* Only one child remains */
911         if (should_collapse(tn))
912                 return collapse(t, tn);
913 
914         /* update parent in case halve failed */
915         return node_parent(tn);
916 }
917 
918 static void node_pull_suffix(struct key_vector *tn, unsigned char slen)
919 {
920         unsigned char node_slen = tn->slen;
921 
922         while ((node_slen > tn->pos) && (node_slen > slen)) {
923                 slen = update_suffix(tn);
924                 if (node_slen == slen)
925                         break;
926 
927                 tn = node_parent(tn);
928                 node_slen = tn->slen;
929         }
930 }
931 
932 static void node_push_suffix(struct key_vector *tn, unsigned char slen)
933 {
934         while (tn->slen < slen) {
935                 tn->slen = slen;
936                 tn = node_parent(tn);
937         }
938 }
939 
940 /* rcu_read_lock needs to be hold by caller from readside */
941 static struct key_vector *fib_find_node(struct trie *t,
942                                         struct key_vector **tp, u32 key)
943 {
944         struct key_vector *pn, *n = t->kv;
945         unsigned long index = 0;
946 
947         do {
948                 pn = n;
949                 n = get_child_rcu(n, index);
950 
951                 if (!n)
952                         break;
953 
954                 index = get_cindex(key, n);
955 
956                 /* This bit of code is a bit tricky but it combines multiple
957                  * checks into a single check.  The prefix consists of the
958                  * prefix plus zeros for the bits in the cindex. The index
959                  * is the difference between the key and this value.  From
960                  * this we can actually derive several pieces of data.
961                  *   if (index >= (1ul << bits))
962                  *     we have a mismatch in skip bits and failed
963                  *   else
964                  *     we know the value is cindex
965                  *
966                  * This check is safe even if bits == KEYLENGTH due to the
967                  * fact that we can only allocate a node with 32 bits if a
968                  * long is greater than 32 bits.
969                  */
970                 if (index >= (1ul << n->bits)) {
971                         n = NULL;
972                         break;
973                 }
974 
975                 /* keep searching until we find a perfect match leaf or NULL */
976         } while (IS_TNODE(n));
977 
978         *tp = pn;
979 
980         return n;
981 }
982 
983 /* Return the first fib alias matching TOS with
984  * priority less than or equal to PRIO.
985  */
986 static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
987                                         u8 tos, u32 prio, u32 tb_id)
988 {
989         struct fib_alias *fa;
990 
991         if (!fah)
992                 return NULL;
993 
994         hlist_for_each_entry(fa, fah, fa_list) {
995                 if (fa->fa_slen < slen)
996                         continue;
997                 if (fa->fa_slen != slen)
998                         break;
999                 if (fa->tb_id > tb_id)
1000                         continue;
1001                 if (fa->tb_id != tb_id)
1002                         break;
1003                 if (fa->fa_tos > tos)
1004                         continue;
1005                 if (fa->fa_info->fib_priority >= prio || fa->fa_tos < tos)
1006                         return fa;
1007         }
1008 
1009         return NULL;
1010 }
1011 
1012 static void trie_rebalance(struct trie *t, struct key_vector *tn)
1013 {
1014         while (!IS_TRIE(tn))
1015                 tn = resize(t, tn);
1016 }
1017 
1018 static int fib_insert_node(struct trie *t, struct key_vector *tp,
1019                            struct fib_alias *new, t_key key)
1020 {
1021         struct key_vector *n, *l;
1022 
1023         l = leaf_new(key, new);
1024         if (!l)
1025                 goto noleaf;
1026 
1027         /* retrieve child from parent node */
1028         n = get_child(tp, get_index(key, tp));
1029 
1030         /* Case 2: n is a LEAF or a TNODE and the key doesn't match.
1031          *
1032          *  Add a new tnode here
1033          *  first tnode need some special handling
1034          *  leaves us in position for handling as case 3
1035          */
1036         if (n) {
1037                 struct key_vector *tn;
1038 
1039                 tn = tnode_new(key, __fls(key ^ n->key), 1);
1040                 if (!tn)
1041                         goto notnode;
1042 
1043                 /* initialize routes out of node */
1044                 NODE_INIT_PARENT(tn, tp);
1045                 put_child(tn, get_index(key, tn) ^ 1, n);
1046 
1047                 /* start adding routes into the node */
1048                 put_child_root(tp, key, tn);
1049                 node_set_parent(n, tn);
1050 
1051                 /* parent now has a NULL spot where the leaf can go */
1052                 tp = tn;
1053         }
1054 
1055         /* Case 3: n is NULL, and will just insert a new leaf */
1056         node_push_suffix(tp, new->fa_slen);
1057         NODE_INIT_PARENT(l, tp);
1058         put_child_root(tp, key, l);
1059         trie_rebalance(t, tp);
1060 
1061         return 0;
1062 notnode:
1063         node_free(l);
1064 noleaf:
1065         return -ENOMEM;
1066 }
1067 
1068 /* fib notifier for ADD is sent before calling fib_insert_alias with
1069  * the expectation that the only possible failure ENOMEM
1070  */
1071 static int fib_insert_alias(struct trie *t, struct key_vector *tp,
1072                             struct key_vector *l, struct fib_alias *new,
1073                             struct fib_alias *fa, t_key key)
1074 {
1075         if (!l)
1076                 return fib_insert_node(t, tp, new, key);
1077 
1078         if (fa) {
1079                 hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
1080         } else {
1081                 struct fib_alias *last;
1082 
1083                 hlist_for_each_entry(last, &l->leaf, fa_list) {
1084                         if (new->fa_slen < last->fa_slen)
1085                                 break;
1086                         if ((new->fa_slen == last->fa_slen) &&
1087                             (new->tb_id > last->tb_id))
1088                                 break;
1089                         fa = last;
1090                 }
1091 
1092                 if (fa)
1093                         hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
1094                 else
1095                         hlist_add_head_rcu(&new->fa_list, &l->leaf);
1096         }
1097 
1098         /* if we added to the tail node then we need to update slen */
1099         if (l->slen < new->fa_slen) {
1100                 l->slen = new->fa_slen;
1101                 node_push_suffix(tp, new->fa_slen);
1102         }
1103 
1104         return 0;
1105 }
1106 
1107 static bool fib_valid_key_len(u32 key, u8 plen, struct netlink_ext_ack *extack)
1108 {
1109         if (plen > KEYLENGTH) {
1110                 NL_SET_ERR_MSG(extack, "Invalid prefix length");
1111                 return false;
1112         }
1113 
1114         if ((plen < KEYLENGTH) && (key << plen)) {
1115                 NL_SET_ERR_MSG(extack,
1116                                "Invalid prefix for given prefix length");
1117                 return false;
1118         }
1119 
1120         return true;
1121 }
1122 
1123 /* Caller must hold RTNL. */
1124 int fib_table_insert(struct net *net, struct fib_table *tb,
1125                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1126 {
1127         enum fib_event_type event = FIB_EVENT_ENTRY_ADD;
1128         struct trie *t = (struct trie *)tb->tb_data;
1129         struct fib_alias *fa, *new_fa;
1130         struct key_vector *l, *tp;
1131         u16 nlflags = NLM_F_EXCL;
1132         struct fib_info *fi;
1133         u8 plen = cfg->fc_dst_len;
1134         u8 slen = KEYLENGTH - plen;
1135         u8 tos = cfg->fc_tos;
1136         u32 key;
1137         int err;
1138 
1139         key = ntohl(cfg->fc_dst);
1140 
1141         if (!fib_valid_key_len(key, plen, extack))
1142                 return -EINVAL;
1143 
1144         pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
1145 
1146         fi = fib_create_info(cfg, extack);
1147         if (IS_ERR(fi)) {
1148                 err = PTR_ERR(fi);
1149                 goto err;
1150         }
1151 
1152         l = fib_find_node(t, &tp, key);
1153         fa = l ? fib_find_alias(&l->leaf, slen, tos, fi->fib_priority,
1154                                 tb->tb_id) : NULL;
1155 
1156         /* Now fa, if non-NULL, points to the first fib alias
1157          * with the same keys [prefix,tos,priority], if such key already
1158          * exists or to the node before which we will insert new one.
1159          *
1160          * If fa is NULL, we will need to allocate a new one and
1161          * insert to the tail of the section matching the suffix length
1162          * of the new alias.
1163          */
1164 
1165         if (fa && fa->fa_tos == tos &&
1166             fa->fa_info->fib_priority == fi->fib_priority) {
1167                 struct fib_alias *fa_first, *fa_match;
1168 
1169                 err = -EEXIST;
1170                 if (cfg->fc_nlflags & NLM_F_EXCL)
1171                         goto out;
1172 
1173                 nlflags &= ~NLM_F_EXCL;
1174 
1175                 /* We have 2 goals:
1176                  * 1. Find exact match for type, scope, fib_info to avoid
1177                  * duplicate routes
1178                  * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
1179                  */
1180                 fa_match = NULL;
1181                 fa_first = fa;
1182                 hlist_for_each_entry_from(fa, fa_list) {
1183                         if ((fa->fa_slen != slen) ||
1184                             (fa->tb_id != tb->tb_id) ||
1185                             (fa->fa_tos != tos))
1186                                 break;
1187                         if (fa->fa_info->fib_priority != fi->fib_priority)
1188                                 break;
1189                         if (fa->fa_type == cfg->fc_type &&
1190                             fa->fa_info == fi) {
1191                                 fa_match = fa;
1192                                 break;
1193                         }
1194                 }
1195 
1196                 if (cfg->fc_nlflags & NLM_F_REPLACE) {
1197                         struct fib_info *fi_drop;
1198                         u8 state;
1199 
1200                         nlflags |= NLM_F_REPLACE;
1201                         fa = fa_first;
1202                         if (fa_match) {
1203                                 if (fa == fa_match)
1204                                         err = 0;
1205                                 goto out;
1206                         }
1207                         err = -ENOBUFS;
1208                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1209                         if (!new_fa)
1210                                 goto out;
1211 
1212                         fi_drop = fa->fa_info;
1213                         new_fa->fa_tos = fa->fa_tos;
1214                         new_fa->fa_info = fi;
1215                         new_fa->fa_type = cfg->fc_type;
1216                         state = fa->fa_state;
1217                         new_fa->fa_state = state & ~FA_S_ACCESSED;
1218                         new_fa->fa_slen = fa->fa_slen;
1219                         new_fa->tb_id = tb->tb_id;
1220                         new_fa->fa_default = -1;
1221 
1222                         err = call_fib_entry_notifiers(net,
1223                                                        FIB_EVENT_ENTRY_REPLACE,
1224                                                        key, plen, new_fa,
1225                                                        extack);
1226                         if (err)
1227                                 goto out_free_new_fa;
1228 
1229                         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
1230                                   tb->tb_id, &cfg->fc_nlinfo, nlflags);
1231 
1232                         hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
1233 
1234                         alias_free_mem_rcu(fa);
1235 
1236                         fib_release_info(fi_drop);
1237                         if (state & FA_S_ACCESSED)
1238                                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1239 
1240                         goto succeeded;
1241                 }
1242                 /* Error if we find a perfect match which
1243                  * uses the same scope, type, and nexthop
1244                  * information.
1245                  */
1246                 if (fa_match)
1247                         goto out;
1248 
1249                 if (cfg->fc_nlflags & NLM_F_APPEND) {
1250                         event = FIB_EVENT_ENTRY_APPEND;
1251                         nlflags |= NLM_F_APPEND;
1252                 } else {
1253                         fa = fa_first;
1254                 }
1255         }
1256         err = -ENOENT;
1257         if (!(cfg->fc_nlflags & NLM_F_CREATE))
1258                 goto out;
1259 
1260         nlflags |= NLM_F_CREATE;
1261         err = -ENOBUFS;
1262         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1263         if (!new_fa)
1264                 goto out;
1265 
1266         new_fa->fa_info = fi;
1267         new_fa->fa_tos = tos;
1268         new_fa->fa_type = cfg->fc_type;
1269         new_fa->fa_state = 0;
1270         new_fa->fa_slen = slen;
1271         new_fa->tb_id = tb->tb_id;
1272         new_fa->fa_default = -1;
1273 
1274         err = call_fib_entry_notifiers(net, event, key, plen, new_fa, extack);
1275         if (err)
1276                 goto out_free_new_fa;
1277 
1278         /* Insert new entry to the list. */
1279         err = fib_insert_alias(t, tp, l, new_fa, fa, key);
1280         if (err)
1281                 goto out_fib_notif;
1282 
1283         if (!plen)
1284                 tb->tb_num_default++;
1285 
1286         rt_cache_flush(cfg->fc_nlinfo.nl_net);
1287         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
1288                   &cfg->fc_nlinfo, nlflags);
1289 succeeded:
1290         return 0;
1291 
1292 out_fib_notif:
1293         /* notifier was sent that entry would be added to trie, but
1294          * the add failed and need to recover. Only failure for
1295          * fib_insert_alias is ENOMEM.
1296          */
1297         NL_SET_ERR_MSG(extack, "Failed to insert route into trie");
1298         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key,
1299                                  plen, new_fa, NULL);
1300 out_free_new_fa:
1301         kmem_cache_free(fn_alias_kmem, new_fa);
1302 out:
1303         fib_release_info(fi);
1304 err:
1305         return err;
1306 }
1307 
1308 static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
1309 {
1310         t_key prefix = n->key;
1311 
1312         return (key ^ prefix) & (prefix | -prefix);
1313 }
1314 
1315 /* should be called with rcu_read_lock */
1316 int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
1317                      struct fib_result *res, int fib_flags)
1318 {
1319         struct trie *t = (struct trie *) tb->tb_data;
1320 #ifdef CONFIG_IP_FIB_TRIE_STATS
1321         struct trie_use_stats __percpu *stats = t->stats;
1322 #endif
1323         const t_key key = ntohl(flp->daddr);
1324         struct key_vector *n, *pn;
1325         struct fib_alias *fa;
1326         unsigned long index;
1327         t_key cindex;
1328 
1329         pn = t->kv;
1330         cindex = 0;
1331 
1332         n = get_child_rcu(pn, cindex);
1333         if (!n) {
1334                 trace_fib_table_lookup(tb->tb_id, flp, NULL, -EAGAIN);
1335                 return -EAGAIN;
1336         }
1337 
1338 #ifdef CONFIG_IP_FIB_TRIE_STATS
1339         this_cpu_inc(stats->gets);
1340 #endif
1341 
1342         /* Step 1: Travel to the longest prefix match in the trie */
1343         for (;;) {
1344                 index = get_cindex(key, n);
1345 
1346                 /* This bit of code is a bit tricky but it combines multiple
1347                  * checks into a single check.  The prefix consists of the
1348                  * prefix plus zeros for the "bits" in the prefix. The index
1349                  * is the difference between the key and this value.  From
1350                  * this we can actually derive several pieces of data.
1351                  *   if (index >= (1ul << bits))
1352                  *     we have a mismatch in skip bits and failed
1353                  *   else
1354                  *     we know the value is cindex
1355                  *
1356                  * This check is safe even if bits == KEYLENGTH due to the
1357                  * fact that we can only allocate a node with 32 bits if a
1358                  * long is greater than 32 bits.
1359                  */
1360                 if (index >= (1ul << n->bits))
1361                         break;
1362 
1363                 /* we have found a leaf. Prefixes have already been compared */
1364                 if (IS_LEAF(n))
1365                         goto found;
1366 
1367                 /* only record pn and cindex if we are going to be chopping
1368                  * bits later.  Otherwise we are just wasting cycles.
1369                  */
1370                 if (n->slen > n->pos) {
1371                         pn = n;
1372                         cindex = index;
1373                 }
1374 
1375                 n = get_child_rcu(n, index);
1376                 if (unlikely(!n))
1377                         goto backtrace;
1378         }
1379 
1380         /* Step 2: Sort out leaves and begin backtracing for longest prefix */
1381         for (;;) {
1382                 /* record the pointer where our next node pointer is stored */
1383                 struct key_vector __rcu **cptr = n->tnode;
1384 
1385                 /* This test verifies that none of the bits that differ
1386                  * between the key and the prefix exist in the region of
1387                  * the lsb and higher in the prefix.
1388                  */
1389                 if (unlikely(prefix_mismatch(key, n)) || (n->slen == n->pos))
1390                         goto backtrace;
1391 
1392                 /* exit out and process leaf */
1393                 if (unlikely(IS_LEAF(n)))
1394                         break;
1395 
1396                 /* Don't bother recording parent info.  Since we are in
1397                  * prefix match mode we will have to come back to wherever
1398                  * we started this traversal anyway
1399                  */
1400 
1401                 while ((n = rcu_dereference(*cptr)) == NULL) {
1402 backtrace:
1403 #ifdef CONFIG_IP_FIB_TRIE_STATS
1404                         if (!n)
1405                                 this_cpu_inc(stats->null_node_hit);
1406 #endif
1407                         /* If we are at cindex 0 there are no more bits for
1408                          * us to strip at this level so we must ascend back
1409                          * up one level to see if there are any more bits to
1410                          * be stripped there.
1411                          */
1412                         while (!cindex) {
1413                                 t_key pkey = pn->key;
1414 
1415                                 /* If we don't have a parent then there is
1416                                  * nothing for us to do as we do not have any
1417                                  * further nodes to parse.
1418                                  */
1419                                 if (IS_TRIE(pn)) {
1420                                         trace_fib_table_lookup(tb->tb_id, flp,
1421                                                                NULL, -EAGAIN);
1422                                         return -EAGAIN;
1423                                 }
1424 #ifdef CONFIG_IP_FIB_TRIE_STATS
1425                                 this_cpu_inc(stats->backtrack);
1426 #endif
1427                                 /* Get Child's index */
1428                                 pn = node_parent_rcu(pn);
1429                                 cindex = get_index(pkey, pn);
1430                         }
1431 
1432                         /* strip the least significant bit from the cindex */
1433                         cindex &= cindex - 1;
1434 
1435                         /* grab pointer for next child node */
1436                         cptr = &pn->tnode[cindex];
1437                 }
1438         }
1439 
1440 found:
1441         /* this line carries forward the xor from earlier in the function */
1442         index = key ^ n->key;
1443 
1444         /* Step 3: Process the leaf, if that fails fall back to backtracing */
1445         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
1446                 struct fib_info *fi = fa->fa_info;
1447                 int nhsel, err;
1448 
1449                 if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) {
1450                         if (index >= (1ul << fa->fa_slen))
1451                                 continue;
1452                 }
1453                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1454                         continue;
1455                 if (fi->fib_dead)
1456                         continue;
1457                 if (fa->fa_info->fib_scope < flp->flowi4_scope)
1458                         continue;
1459                 fib_alias_accessed(fa);
1460                 err = fib_props[fa->fa_type].error;
1461                 if (unlikely(err < 0)) {
1462 #ifdef CONFIG_IP_FIB_TRIE_STATS
1463                         this_cpu_inc(stats->semantic_match_passed);
1464 #endif
1465                         trace_fib_table_lookup(tb->tb_id, flp, NULL, err);
1466                         return err;
1467                 }
1468                 if (fi->fib_flags & RTNH_F_DEAD)
1469                         continue;
1470                 for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
1471                         const struct fib_nh *nh = &fi->fib_nh[nhsel];
1472                         struct in_device *in_dev = __in_dev_get_rcu(nh->nh_dev);
1473 
1474                         if (nh->nh_flags & RTNH_F_DEAD)
1475                                 continue;
1476                         if (in_dev &&
1477                             IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1478                             nh->nh_flags & RTNH_F_LINKDOWN &&
1479                             !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
1480                                 continue;
1481                         if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) {
1482                                 if (flp->flowi4_oif &&
1483                                     flp->flowi4_oif != nh->nh_oif)
1484                                         continue;
1485                         }
1486 
1487                         if (!(fib_flags & FIB_LOOKUP_NOREF))
1488                                 refcount_inc(&fi->fib_clntref);
1489 
1490                         res->prefix = htonl(n->key);
1491                         res->prefixlen = KEYLENGTH - fa->fa_slen;
1492                         res->nh_sel = nhsel;
1493                         res->type = fa->fa_type;
1494                         res->scope = fi->fib_scope;
1495                         res->fi = fi;
1496                         res->table = tb;
1497                         res->fa_head = &n->leaf;
1498 #ifdef CONFIG_IP_FIB_TRIE_STATS
1499                         this_cpu_inc(stats->semantic_match_passed);
1500 #endif
1501                         trace_fib_table_lookup(tb->tb_id, flp, nh, err);
1502 
1503                         return err;
1504                 }
1505         }
1506 #ifdef CONFIG_IP_FIB_TRIE_STATS
1507         this_cpu_inc(stats->semantic_match_miss);
1508 #endif
1509         goto backtrace;
1510 }
1511 EXPORT_SYMBOL_GPL(fib_table_lookup);
1512 
1513 static void fib_remove_alias(struct trie *t, struct key_vector *tp,
1514                              struct key_vector *l, struct fib_alias *old)
1515 {
1516         /* record the location of the previous list_info entry */
1517         struct hlist_node **pprev = old->fa_list.pprev;
1518         struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
1519 
1520         /* remove the fib_alias from the list */
1521         hlist_del_rcu(&old->fa_list);
1522 
1523         /* if we emptied the list this leaf will be freed and we can sort
1524          * out parent suffix lengths as a part of trie_rebalance
1525          */
1526         if (hlist_empty(&l->leaf)) {
1527                 if (tp->slen == l->slen)
1528                         node_pull_suffix(tp, tp->pos);
1529                 put_child_root(tp, l->key, NULL);
1530                 node_free(l);
1531                 trie_rebalance(t, tp);
1532                 return;
1533         }
1534 
1535         /* only access fa if it is pointing at the last valid hlist_node */
1536         if (*pprev)
1537                 return;
1538 
1539         /* update the trie with the latest suffix length */
1540         l->slen = fa->fa_slen;
1541         node_pull_suffix(tp, fa->fa_slen);
1542 }
1543 
1544 /* Caller must hold RTNL. */
1545 int fib_table_delete(struct net *net, struct fib_table *tb,
1546                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1547 {
1548         struct trie *t = (struct trie *) tb->tb_data;
1549         struct fib_alias *fa, *fa_to_delete;
1550         struct key_vector *l, *tp;
1551         u8 plen = cfg->fc_dst_len;
1552         u8 slen = KEYLENGTH - plen;
1553         u8 tos = cfg->fc_tos;
1554         u32 key;
1555 
1556         key = ntohl(cfg->fc_dst);
1557 
1558         if (!fib_valid_key_len(key, plen, extack))
1559                 return -EINVAL;
1560 
1561         l = fib_find_node(t, &tp, key);
1562         if (!l)
1563                 return -ESRCH;
1564 
1565         fa = fib_find_alias(&l->leaf, slen, tos, 0, tb->tb_id);
1566         if (!fa)
1567                 return -ESRCH;
1568 
1569         pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
1570 
1571         fa_to_delete = NULL;
1572         hlist_for_each_entry_from(fa, fa_list) {
1573                 struct fib_info *fi = fa->fa_info;
1574 
1575                 if ((fa->fa_slen != slen) ||
1576                     (fa->tb_id != tb->tb_id) ||
1577                     (fa->fa_tos != tos))
1578                         break;
1579 
1580                 if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
1581                     (cfg->fc_scope == RT_SCOPE_NOWHERE ||
1582                      fa->fa_info->fib_scope == cfg->fc_scope) &&
1583                     (!cfg->fc_prefsrc ||
1584                      fi->fib_prefsrc == cfg->fc_prefsrc) &&
1585                     (!cfg->fc_protocol ||
1586                      fi->fib_protocol == cfg->fc_protocol) &&
1587                     fib_nh_match(cfg, fi, extack) == 0 &&
1588                     fib_metrics_match(cfg, fi)) {
1589                         fa_to_delete = fa;
1590                         break;
1591                 }
1592         }
1593 
1594         if (!fa_to_delete)
1595                 return -ESRCH;
1596 
1597         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key, plen,
1598                                  fa_to_delete, extack);
1599         rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
1600                   &cfg->fc_nlinfo, 0);
1601 
1602         if (!plen)
1603                 tb->tb_num_default--;
1604 
1605         fib_remove_alias(t, tp, l, fa_to_delete);
1606 
1607         if (fa_to_delete->fa_state & FA_S_ACCESSED)
1608                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1609 
1610         fib_release_info(fa_to_delete->fa_info);
1611         alias_free_mem_rcu(fa_to_delete);
1612         return 0;
1613 }
1614 
1615 /* Scan for the next leaf starting at the provided key value */
1616 static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
1617 {
1618         struct key_vector *pn, *n = *tn;
1619         unsigned long cindex;
1620 
1621         /* this loop is meant to try and find the key in the trie */
1622         do {
1623                 /* record parent and next child index */
1624                 pn = n;
1625                 cindex = (key > pn->key) ? get_index(key, pn) : 0;
1626 
1627                 if (cindex >> pn->bits)
1628                         break;
1629 
1630                 /* descend into the next child */
1631                 n = get_child_rcu(pn, cindex++);
1632                 if (!n)
1633                         break;
1634 
1635                 /* guarantee forward progress on the keys */
1636                 if (IS_LEAF(n) && (n->key >= key))
1637                         goto found;
1638         } while (IS_TNODE(n));
1639 
1640         /* this loop will search for the next leaf with a greater key */
1641         while (!IS_TRIE(pn)) {
1642                 /* if we exhausted the parent node we will need to climb */
1643                 if (cindex >= (1ul << pn->bits)) {
1644                         t_key pkey = pn->key;
1645 
1646                         pn = node_parent_rcu(pn);
1647                         cindex = get_index(pkey, pn) + 1;
1648                         continue;
1649                 }
1650 
1651                 /* grab the next available node */
1652                 n = get_child_rcu(pn, cindex++);
1653                 if (!n)
1654                         continue;
1655 
1656                 /* no need to compare keys since we bumped the index */
1657                 if (IS_LEAF(n))
1658                         goto found;
1659 
1660                 /* Rescan start scanning in new node */
1661                 pn = n;
1662                 cindex = 0;
1663         }
1664 
1665         *tn = pn;
1666         return NULL; /* Root of trie */
1667 found:
1668         /* if we are at the limit for keys just return NULL for the tnode */
1669         *tn = pn;
1670         return n;
1671 }
1672 
1673 static void fib_trie_free(struct fib_table *tb)
1674 {
1675         struct trie *t = (struct trie *)tb->tb_data;
1676         struct key_vector *pn = t->kv;
1677         unsigned long cindex = 1;
1678         struct hlist_node *tmp;
1679         struct fib_alias *fa;
1680 
1681         /* walk trie in reverse order and free everything */
1682         for (;;) {
1683                 struct key_vector *n;
1684 
1685                 if (!(cindex--)) {
1686                         t_key pkey = pn->key;
1687 
1688                         if (IS_TRIE(pn))
1689                                 break;
1690 
1691                         n = pn;
1692                         pn = node_parent(pn);
1693 
1694                         /* drop emptied tnode */
1695                         put_child_root(pn, n->key, NULL);
1696                         node_free(n);
1697 
1698                         cindex = get_index(pkey, pn);
1699 
1700                         continue;
1701                 }
1702 
1703                 /* grab the next available node */
1704                 n = get_child(pn, cindex);
1705                 if (!n)
1706                         continue;
1707 
1708                 if (IS_TNODE(n)) {
1709                         /* record pn and cindex for leaf walking */
1710                         pn = n;
1711                         cindex = 1ul << n->bits;
1712 
1713                         continue;
1714                 }
1715 
1716                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1717                         hlist_del_rcu(&fa->fa_list);
1718                         alias_free_mem_rcu(fa);
1719                 }
1720 
1721                 put_child_root(pn, n->key, NULL);
1722                 node_free(n);
1723         }
1724 
1725 #ifdef CONFIG_IP_FIB_TRIE_STATS
1726         free_percpu(t->stats);
1727 #endif
1728         kfree(tb);
1729 }
1730 
1731 struct fib_table *fib_trie_unmerge(struct fib_table *oldtb)
1732 {
1733         struct trie *ot = (struct trie *)oldtb->tb_data;
1734         struct key_vector *l, *tp = ot->kv;
1735         struct fib_table *local_tb;
1736         struct fib_alias *fa;
1737         struct trie *lt;
1738         t_key key = 0;
1739 
1740         if (oldtb->tb_data == oldtb->__data)
1741                 return oldtb;
1742 
1743         local_tb = fib_trie_table(RT_TABLE_LOCAL, NULL);
1744         if (!local_tb)
1745                 return NULL;
1746 
1747         lt = (struct trie *)local_tb->tb_data;
1748 
1749         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1750                 struct key_vector *local_l = NULL, *local_tp;
1751 
1752                 hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1753                         struct fib_alias *new_fa;
1754 
1755                         if (local_tb->tb_id != fa->tb_id)
1756                                 continue;
1757 
1758                         /* clone fa for new local table */
1759                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1760                         if (!new_fa)
1761                                 goto out;
1762 
1763                         memcpy(new_fa, fa, sizeof(*fa));
1764 
1765                         /* insert clone into table */
1766                         if (!local_l)
1767                                 local_l = fib_find_node(lt, &local_tp, l->key);
1768 
1769                         if (fib_insert_alias(lt, local_tp, local_l, new_fa,
1770                                              NULL, l->key)) {
1771                                 kmem_cache_free(fn_alias_kmem, new_fa);
1772                                 goto out;
1773                         }
1774                 }
1775 
1776                 /* stop loop if key wrapped back to 0 */
1777                 key = l->key + 1;
1778                 if (key < l->key)
1779                         break;
1780         }
1781 
1782         return local_tb;
1783 out:
1784         fib_trie_free(local_tb);
1785 
1786         return NULL;
1787 }
1788 
1789 /* Caller must hold RTNL */
1790 void fib_table_flush_external(struct fib_table *tb)
1791 {
1792         struct trie *t = (struct trie *)tb->tb_data;
1793         struct key_vector *pn = t->kv;
1794         unsigned long cindex = 1;
1795         struct hlist_node *tmp;
1796         struct fib_alias *fa;
1797 
1798         /* walk trie in reverse order */
1799         for (;;) {
1800                 unsigned char slen = 0;
1801                 struct key_vector *n;
1802 
1803                 if (!(cindex--)) {
1804                         t_key pkey = pn->key;
1805 
1806                         /* cannot resize the trie vector */
1807                         if (IS_TRIE(pn))
1808                                 break;
1809 
1810                         /* update the suffix to address pulled leaves */
1811                         if (pn->slen > pn->pos)
1812                                 update_suffix(pn);
1813 
1814                         /* resize completed node */
1815                         pn = resize(t, pn);
1816                         cindex = get_index(pkey, pn);
1817 
1818                         continue;
1819                 }
1820 
1821                 /* grab the next available node */
1822                 n = get_child(pn, cindex);
1823                 if (!n)
1824                         continue;
1825 
1826                 if (IS_TNODE(n)) {
1827                         /* record pn and cindex for leaf walking */
1828                         pn = n;
1829                         cindex = 1ul << n->bits;
1830 
1831                         continue;
1832                 }
1833 
1834                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1835                         /* if alias was cloned to local then we just
1836                          * need to remove the local copy from main
1837                          */
1838                         if (tb->tb_id != fa->tb_id) {
1839                                 hlist_del_rcu(&fa->fa_list);
1840                                 alias_free_mem_rcu(fa);
1841                                 continue;
1842                         }
1843 
1844                         /* record local slen */
1845                         slen = fa->fa_slen;
1846                 }
1847 
1848                 /* update leaf slen */
1849                 n->slen = slen;
1850 
1851                 if (hlist_empty(&n->leaf)) {
1852                         put_child_root(pn, n->key, NULL);
1853                         node_free(n);
1854                 }
1855         }
1856 }
1857 
1858 /* Caller must hold RTNL. */
1859 int fib_table_flush(struct net *net, struct fib_table *tb, bool flush_all)
1860 {
1861         struct trie *t = (struct trie *)tb->tb_data;
1862         struct key_vector *pn = t->kv;
1863         unsigned long cindex = 1;
1864         struct hlist_node *tmp;
1865         struct fib_alias *fa;
1866         int found = 0;
1867 
1868         /* walk trie in reverse order */
1869         for (;;) {
1870                 unsigned char slen = 0;
1871                 struct key_vector *n;
1872 
1873                 if (!(cindex--)) {
1874                         t_key pkey = pn->key;
1875 
1876                         /* cannot resize the trie vector */
1877                         if (IS_TRIE(pn))
1878                                 break;
1879 
1880                         /* update the suffix to address pulled leaves */
1881                         if (pn->slen > pn->pos)
1882                                 update_suffix(pn);
1883 
1884                         /* resize completed node */
1885                         pn = resize(t, pn);
1886                         cindex = get_index(pkey, pn);
1887 
1888                         continue;
1889                 }
1890 
1891                 /* grab the next available node */
1892                 n = get_child(pn, cindex);
1893                 if (!n)
1894                         continue;
1895 
1896                 if (IS_TNODE(n)) {
1897                         /* record pn and cindex for leaf walking */
1898                         pn = n;
1899                         cindex = 1ul << n->bits;
1900 
1901                         continue;
1902                 }
1903 
1904                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1905                         struct fib_info *fi = fa->fa_info;
1906 
1907                         if (!fi || tb->tb_id != fa->tb_id ||
1908                             (!(fi->fib_flags & RTNH_F_DEAD) &&
1909                              !fib_props[fa->fa_type].error)) {
1910                                 slen = fa->fa_slen;
1911                                 continue;
1912                         }
1913 
1914                         /* Do not flush error routes if network namespace is
1915                          * not being dismantled
1916                          */
1917                         if (!flush_all && fib_props[fa->fa_type].error) {
1918                                 slen = fa->fa_slen;
1919                                 continue;
1920                         }
1921 
1922                         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
1923                                                  n->key,
1924                                                  KEYLENGTH - fa->fa_slen, fa,
1925                                                  NULL);
1926                         hlist_del_rcu(&fa->fa_list);
1927                         fib_release_info(fa->fa_info);
1928                         alias_free_mem_rcu(fa);
1929                         found++;
1930                 }
1931 
1932                 /* update leaf slen */
1933                 n->slen = slen;
1934 
1935                 if (hlist_empty(&n->leaf)) {
1936                         put_child_root(pn, n->key, NULL);
1937                         node_free(n);
1938                 }
1939         }
1940 
1941         pr_debug("trie_flush found=%d\n", found);
1942         return found;
1943 }
1944 
1945 static void fib_leaf_notify(struct net *net, struct key_vector *l,
1946                             struct fib_table *tb, struct notifier_block *nb)
1947 {
1948         struct fib_alias *fa;
1949 
1950         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1951                 struct fib_info *fi = fa->fa_info;
1952 
1953                 if (!fi)
1954                         continue;
1955 
1956                 /* local and main table can share the same trie,
1957                  * so don't notify twice for the same entry.
1958                  */
1959                 if (tb->tb_id != fa->tb_id)
1960                         continue;
1961 
1962                 call_fib_entry_notifier(nb, net, FIB_EVENT_ENTRY_ADD, l->key,
1963                                         KEYLENGTH - fa->fa_slen, fa);
1964         }
1965 }
1966 
1967 static void fib_table_notify(struct net *net, struct fib_table *tb,
1968                              struct notifier_block *nb)
1969 {
1970         struct trie *t = (struct trie *)tb->tb_data;
1971         struct key_vector *l, *tp = t->kv;
1972         t_key key = 0;
1973 
1974         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1975                 fib_leaf_notify(net, l, tb, nb);
1976 
1977                 key = l->key + 1;
1978                 /* stop in case of wrap around */
1979                 if (key < l->key)
1980                         break;
1981         }
1982 }
1983 
1984 void fib_notify(struct net *net, struct notifier_block *nb)
1985 {
1986         unsigned int h;
1987 
1988         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
1989                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
1990                 struct fib_table *tb;
1991 
1992                 hlist_for_each_entry_rcu(tb, head, tb_hlist)
1993                         fib_table_notify(net, tb, nb);
1994         }
1995 }
1996 
1997 static void __trie_free_rcu(struct rcu_head *head)
1998 {
1999         struct fib_table *tb = container_of(head, struct fib_table, rcu);
2000 #ifdef CONFIG_IP_FIB_TRIE_STATS
2001         struct trie *t = (struct trie *)tb->tb_data;
2002 
2003         if (tb->tb_data == tb->__data)
2004                 free_percpu(t->stats);
2005 #endif /* CONFIG_IP_FIB_TRIE_STATS */
2006         kfree(tb);
2007 }
2008 
2009 void fib_free_table(struct fib_table *tb)
2010 {
2011         call_rcu(&tb->rcu, __trie_free_rcu);
2012 }
2013 
2014 static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
2015                              struct sk_buff *skb, struct netlink_callback *cb,
2016                              struct fib_dump_filter *filter)
2017 {
2018         unsigned int flags = NLM_F_MULTI;
2019         __be32 xkey = htonl(l->key);
2020         struct fib_alias *fa;
2021         int i, s_i;
2022 
2023         if (filter->filter_set)
2024                 flags |= NLM_F_DUMP_FILTERED;
2025 
2026         s_i = cb->args[4];
2027         i = 0;
2028 
2029         /* rcu_read_lock is hold by caller */
2030         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2031                 int err;
2032 
2033                 if (i < s_i)
2034                         goto next;
2035 
2036                 if (tb->tb_id != fa->tb_id)
2037                         goto next;
2038 
2039                 if (filter->filter_set) {
2040                         if (filter->rt_type && fa->fa_type != filter->rt_type)
2041                                 goto next;
2042 
2043                         if ((filter->protocol &&
2044                              fa->fa_info->fib_protocol != filter->protocol))
2045                                 goto next;
2046 
2047                         if (filter->dev &&
2048                             !fib_info_nh_uses_dev(fa->fa_info, filter->dev))
2049                                 goto next;
2050                 }
2051 
2052                 err = fib_dump_info(skb, NETLINK_CB(cb->skb).portid,
2053                                     cb->nlh->nlmsg_seq, RTM_NEWROUTE,
2054                                     tb->tb_id, fa->fa_type,
2055                                     xkey, KEYLENGTH - fa->fa_slen,
2056                                     fa->fa_tos, fa->fa_info, flags);
2057                 if (err < 0) {
2058                         cb->args[4] = i;
2059                         return err;
2060                 }
2061 next:
2062                 i++;
2063         }
2064 
2065         cb->args[4] = i;
2066         return skb->len;
2067 }
2068 
2069 /* rcu_read_lock needs to be hold by caller from readside */
2070 int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
2071                    struct netlink_callback *cb, struct fib_dump_filter *filter)
2072 {
2073         struct trie *t = (struct trie *)tb->tb_data;
2074         struct key_vector *l, *tp = t->kv;
2075         /* Dump starting at last key.
2076          * Note: 0.0.0.0/0 (ie default) is first key.
2077          */
2078         int count = cb->args[2];
2079         t_key key = cb->args[3];
2080 
2081         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
2082                 int err;
2083 
2084                 err = fn_trie_dump_leaf(l, tb, skb, cb, filter);
2085                 if (err < 0) {
2086                         cb->args[3] = key;
2087                         cb->args[2] = count;
2088                         return err;
2089                 }
2090 
2091                 ++count;
2092                 key = l->key + 1;
2093 
2094                 memset(&cb->args[4], 0,
2095                        sizeof(cb->args) - 4*sizeof(cb->args[0]));
2096 
2097                 /* stop loop if key wrapped back to 0 */
2098                 if (key < l->key)
2099                         break;
2100         }
2101 
2102         cb->args[3] = key;
2103         cb->args[2] = count;
2104 
2105         return skb->len;
2106 }
2107 
2108 void __init fib_trie_init(void)
2109 {
2110         fn_alias_kmem = kmem_cache_create("ip_fib_alias",
2111                                           sizeof(struct fib_alias),
2112                                           0, SLAB_PANIC, NULL);
2113 
2114         trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
2115                                            LEAF_SIZE,
2116                                            0, SLAB_PANIC, NULL);
2117 }
2118 
2119 struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
2120 {
2121         struct fib_table *tb;
2122         struct trie *t;
2123         size_t sz = sizeof(*tb);
2124 
2125         if (!alias)
2126                 sz += sizeof(struct trie);
2127 
2128         tb = kzalloc(sz, GFP_KERNEL);
2129         if (!tb)
2130                 return NULL;
2131 
2132         tb->tb_id = id;
2133         tb->tb_num_default = 0;
2134         tb->tb_data = (alias ? alias->__data : tb->__data);
2135 
2136         if (alias)
2137                 return tb;
2138 
2139         t = (struct trie *) tb->tb_data;
2140         t->kv[0].pos = KEYLENGTH;
2141         t->kv[0].slen = KEYLENGTH;
2142 #ifdef CONFIG_IP_FIB_TRIE_STATS
2143         t->stats = alloc_percpu(struct trie_use_stats);
2144         if (!t->stats) {
2145                 kfree(tb);
2146                 tb = NULL;
2147         }
2148 #endif
2149 
2150         return tb;
2151 }
2152 
2153 #ifdef CONFIG_PROC_FS
2154 /* Depth first Trie walk iterator */
2155 struct fib_trie_iter {
2156         struct seq_net_private p;
2157         struct fib_table *tb;
2158         struct key_vector *tnode;
2159         unsigned int index;
2160         unsigned int depth;
2161 };
2162 
2163 static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
2164 {
2165         unsigned long cindex = iter->index;
2166         struct key_vector *pn = iter->tnode;
2167         t_key pkey;
2168 
2169         pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
2170                  iter->tnode, iter->index, iter->depth);
2171 
2172         while (!IS_TRIE(pn)) {
2173                 while (cindex < child_length(pn)) {
2174                         struct key_vector *n = get_child_rcu(pn, cindex++);
2175 
2176                         if (!n)
2177                                 continue;
2178 
2179                         if (IS_LEAF(n)) {
2180                                 iter->tnode = pn;
2181                                 iter->index = cindex;
2182                         } else {
2183                                 /* push down one level */
2184                                 iter->tnode = n;
2185                                 iter->index = 0;
2186                                 ++iter->depth;
2187                         }
2188 
2189                         return n;
2190                 }
2191 
2192                 /* Current node exhausted, pop back up */
2193                 pkey = pn->key;
2194                 pn = node_parent_rcu(pn);
2195                 cindex = get_index(pkey, pn) + 1;
2196                 --iter->depth;
2197         }
2198 
2199         /* record root node so further searches know we are done */
2200         iter->tnode = pn;
2201         iter->index = 0;
2202 
2203         return NULL;
2204 }
2205 
2206 static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
2207                                              struct trie *t)
2208 {
2209         struct key_vector *n, *pn;
2210 
2211         if (!t)
2212                 return NULL;
2213 
2214         pn = t->kv;
2215         n = rcu_dereference(pn->tnode[0]);
2216         if (!n)
2217                 return NULL;
2218 
2219         if (IS_TNODE(n)) {
2220                 iter->tnode = n;
2221                 iter->index = 0;
2222                 iter->depth = 1;
2223         } else {
2224                 iter->tnode = pn;
2225                 iter->index = 0;
2226                 iter->depth = 0;
2227         }
2228 
2229         return n;
2230 }
2231 
2232 static void trie_collect_stats(struct trie *t, struct trie_stat *s)
2233 {
2234         struct key_vector *n;
2235         struct fib_trie_iter iter;
2236 
2237         memset(s, 0, sizeof(*s));
2238 
2239         rcu_read_lock();
2240         for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
2241                 if (IS_LEAF(n)) {
2242                         struct fib_alias *fa;
2243 
2244                         s->leaves++;
2245                         s->totdepth += iter.depth;
2246                         if (iter.depth > s->maxdepth)
2247                                 s->maxdepth = iter.depth;
2248 
2249                         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list)
2250                                 ++s->prefixes;
2251                 } else {
2252                         s->tnodes++;
2253                         if (n->bits < MAX_STAT_DEPTH)
2254                                 s->nodesizes[n->bits]++;
2255                         s->nullpointers += tn_info(n)->empty_children;
2256                 }
2257         }
2258         rcu_read_unlock();
2259 }
2260 
2261 /*
2262  *      This outputs /proc/net/fib_triestats
2263  */
2264 static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
2265 {
2266         unsigned int i, max, pointers, bytes, avdepth;
2267 
2268         if (stat->leaves)
2269                 avdepth = stat->totdepth*100 / stat->leaves;
2270         else
2271                 avdepth = 0;
2272 
2273         seq_printf(seq, "\tAver depth:     %u.%02d\n",
2274                    avdepth / 100, avdepth % 100);
2275         seq_printf(seq, "\tMax depth:      %u\n", stat->maxdepth);
2276 
2277         seq_printf(seq, "\tLeaves:         %u\n", stat->leaves);
2278         bytes = LEAF_SIZE * stat->leaves;
2279 
2280         seq_printf(seq, "\tPrefixes:       %u\n", stat->prefixes);
2281         bytes += sizeof(struct fib_alias) * stat->prefixes;
2282 
2283         seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
2284         bytes += TNODE_SIZE(0) * stat->tnodes;
2285 
2286         max = MAX_STAT_DEPTH;
2287         while (max > 0 && stat->nodesizes[max-1] == 0)
2288                 max--;
2289 
2290         pointers = 0;
2291         for (i = 1; i < max; i++)
2292                 if (stat->nodesizes[i] != 0) {
2293                         seq_printf(seq, "  %u: %u",  i, stat->nodesizes[i]);
2294                         pointers += (1<<i) * stat->nodesizes[i];
2295                 }
2296         seq_putc(seq, '\n');
2297         seq_printf(seq, "\tPointers: %u\n", pointers);
2298 
2299         bytes += sizeof(struct key_vector *) * pointers;
2300         seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
2301         seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
2302 }
2303 
2304 #ifdef CONFIG_IP_FIB_TRIE_STATS
2305 static void trie_show_usage(struct seq_file *seq,
2306                             const struct trie_use_stats __percpu *stats)
2307 {
2308         struct trie_use_stats s = { 0 };
2309         int cpu;
2310 
2311         /* loop through all of the CPUs and gather up the stats */
2312         for_each_possible_cpu(cpu) {
2313                 const struct trie_use_stats *pcpu = per_cpu_ptr(stats, cpu);
2314 
2315                 s.gets += pcpu->gets;
2316                 s.backtrack += pcpu->backtrack;
2317                 s.semantic_match_passed += pcpu->semantic_match_passed;
2318                 s.semantic_match_miss += pcpu->semantic_match_miss;
2319                 s.null_node_hit += pcpu->null_node_hit;
2320                 s.resize_node_skipped += pcpu->resize_node_skipped;
2321         }
2322 
2323         seq_printf(seq, "\nCounters:\n---------\n");
2324         seq_printf(seq, "gets = %u\n", s.gets);
2325         seq_printf(seq, "backtracks = %u\n", s.backtrack);
2326         seq_printf(seq, "semantic match passed = %u\n",
2327                    s.semantic_match_passed);
2328         seq_printf(seq, "semantic match miss = %u\n", s.semantic_match_miss);
2329         seq_printf(seq, "null node hit= %u\n", s.null_node_hit);
2330         seq_printf(seq, "skipped node resize = %u\n\n", s.resize_node_skipped);
2331 }
2332 #endif /*  CONFIG_IP_FIB_TRIE_STATS */
2333 
2334 static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
2335 {
2336         if (tb->tb_id == RT_TABLE_LOCAL)
2337                 seq_puts(seq, "Local:\n");
2338         else if (tb->tb_id == RT_TABLE_MAIN)
2339                 seq_puts(seq, "Main:\n");
2340         else
2341                 seq_printf(seq, "Id %d:\n", tb->tb_id);
2342 }
2343 
2344 
2345 static int fib_triestat_seq_show(struct seq_file *seq, void *v)
2346 {
2347         struct net *net = (struct net *)seq->private;
2348         unsigned int h;
2349 
2350         seq_printf(seq,
2351                    "Basic info: size of leaf:"
2352                    " %zd bytes, size of tnode: %zd bytes.\n",
2353                    LEAF_SIZE, TNODE_SIZE(0));
2354 
2355         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2356                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2357                 struct fib_table *tb;
2358 
2359                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2360                         struct trie *t = (struct trie *) tb->tb_data;
2361                         struct trie_stat stat;
2362 
2363                         if (!t)
2364                                 continue;
2365 
2366                         fib_table_print(seq, tb);
2367 
2368                         trie_collect_stats(t, &stat);
2369                         trie_show_stats(seq, &stat);
2370 #ifdef CONFIG_IP_FIB_TRIE_STATS
2371                         trie_show_usage(seq, t->stats);
2372 #endif
2373                 }
2374         }
2375 
2376         return 0;
2377 }
2378 
2379 static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
2380 {
2381         struct fib_trie_iter *iter = seq->private;
2382         struct net *net = seq_file_net(seq);
2383         loff_t idx = 0;
2384         unsigned int h;
2385 
2386         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2387                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2388                 struct fib_table *tb;
2389 
2390                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2391                         struct key_vector *n;
2392 
2393                         for (n = fib_trie_get_first(iter,
2394                                                     (struct trie *) tb->tb_data);
2395                              n; n = fib_trie_get_next(iter))
2396                                 if (pos == idx++) {
2397                                         iter->tb = tb;
2398                                         return n;
2399                                 }
2400                 }
2401         }
2402 
2403         return NULL;
2404 }
2405 
2406 static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
2407         __acquires(RCU)
2408 {
2409         rcu_read_lock();
2410         return fib_trie_get_idx(seq, *pos);
2411 }
2412 
2413 static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2414 {
2415         struct fib_trie_iter *iter = seq->private;
2416         struct net *net = seq_file_net(seq);
2417         struct fib_table *tb = iter->tb;
2418         struct hlist_node *tb_node;
2419         unsigned int h;
2420         struct key_vector *n;
2421 
2422         ++*pos;
2423         /* next node in same table */
2424         n = fib_trie_get_next(iter);
2425         if (n)
2426                 return n;
2427 
2428         /* walk rest of this hash chain */
2429         h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
2430         while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
2431                 tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
2432                 n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2433                 if (n)
2434                         goto found;
2435         }
2436 
2437         /* new hash chain */
2438         while (++h < FIB_TABLE_HASHSZ) {
2439                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2440                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2441                         n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2442                         if (n)
2443                                 goto found;
2444                 }
2445         }
2446         return NULL;
2447 
2448 found:
2449         iter->tb = tb;
2450         return n;
2451 }
2452 
2453 static void fib_trie_seq_stop(struct seq_file *seq, void *v)
2454         __releases(RCU)
2455 {
2456         rcu_read_unlock();
2457 }
2458 
2459 static void seq_indent(struct seq_file *seq, int n)
2460 {
2461         while (n-- > 0)
2462                 seq_puts(seq, "   ");
2463 }
2464 
2465 static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
2466 {
2467         switch (s) {
2468         case RT_SCOPE_UNIVERSE: return "universe";
2469         case RT_SCOPE_SITE:     return "site";
2470         case RT_SCOPE_LINK:     return "link";
2471         case RT_SCOPE_HOST:     return "host";
2472         case RT_SCOPE_NOWHERE:  return "nowhere";
2473         default:
2474                 snprintf(buf, len, "scope=%d", s);
2475                 return buf;
2476         }
2477 }
2478 
2479 static const char *const rtn_type_names[__RTN_MAX] = {
2480         [RTN_UNSPEC] = "UNSPEC",
2481         [RTN_UNICAST] = "UNICAST",
2482         [RTN_LOCAL] = "LOCAL",
2483         [RTN_BROADCAST] = "BROADCAST",
2484         [RTN_ANYCAST] = "ANYCAST",
2485         [RTN_MULTICAST] = "MULTICAST",
2486         [RTN_BLACKHOLE] = "BLACKHOLE",
2487         [RTN_UNREACHABLE] = "UNREACHABLE",
2488         [RTN_PROHIBIT] = "PROHIBIT",
2489         [RTN_THROW] = "THROW",
2490         [RTN_NAT] = "NAT",
2491         [RTN_XRESOLVE] = "XRESOLVE",
2492 };
2493 
2494 static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
2495 {
2496         if (t < __RTN_MAX && rtn_type_names[t])
2497                 return rtn_type_names[t];
2498         snprintf(buf, len, "type %u", t);
2499         return buf;
2500 }
2501 
2502 /* Pretty print the trie */
2503 static int fib_trie_seq_show(struct seq_file *seq, void *v)
2504 {
2505         const struct fib_trie_iter *iter = seq->private;
2506         struct key_vector *n = v;
2507 
2508         if (IS_TRIE(node_parent_rcu(n)))
2509                 fib_table_print(seq, iter->tb);
2510 
2511         if (IS_TNODE(n)) {
2512                 __be32 prf = htonl(n->key);
2513 
2514                 seq_indent(seq, iter->depth-1);
2515                 seq_printf(seq, "  +-- %pI4/%zu %u %u %u\n",
2516                            &prf, KEYLENGTH - n->pos - n->bits, n->bits,
2517                            tn_info(n)->full_children,
2518                            tn_info(n)->empty_children);
2519         } else {
2520                 __be32 val = htonl(n->key);
2521                 struct fib_alias *fa;
2522 
2523                 seq_indent(seq, iter->depth);
2524                 seq_printf(seq, "  |-- %pI4\n", &val);
2525 
2526                 hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
2527                         char buf1[32], buf2[32];
2528 
2529                         seq_indent(seq, iter->depth + 1);
2530                         seq_printf(seq, "  /%zu %s %s",
2531                                    KEYLENGTH - fa->fa_slen,
2532                                    rtn_scope(buf1, sizeof(buf1),
2533                                              fa->fa_info->fib_scope),
2534                                    rtn_type(buf2, sizeof(buf2),
2535                                             fa->fa_type));
2536                         if (fa->fa_tos)
2537                                 seq_printf(seq, " tos=%d", fa->fa_tos);
2538                         seq_putc(seq, '\n');
2539                 }
2540         }
2541 
2542         return 0;
2543 }
2544 
2545 static const struct seq_operations fib_trie_seq_ops = {
2546         .start  = fib_trie_seq_start,
2547         .next   = fib_trie_seq_next,
2548         .stop   = fib_trie_seq_stop,
2549         .show   = fib_trie_seq_show,
2550 };
2551 
2552 struct fib_route_iter {
2553         struct seq_net_private p;
2554         struct fib_table *main_tb;
2555         struct key_vector *tnode;
2556         loff_t  pos;
2557         t_key   key;
2558 };
2559 
2560 static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
2561                                             loff_t pos)
2562 {
2563         struct key_vector *l, **tp = &iter->tnode;
2564         t_key key;
2565 
2566         /* use cached location of previously found key */
2567         if (iter->pos > 0 && pos >= iter->pos) {
2568                 key = iter->key;
2569         } else {
2570                 iter->pos = 1;
2571                 key = 0;
2572         }
2573 
2574         pos -= iter->pos;
2575 
2576         while ((l = leaf_walk_rcu(tp, key)) && (pos-- > 0)) {
2577                 key = l->key + 1;
2578                 iter->pos++;
2579                 l = NULL;
2580 
2581                 /* handle unlikely case of a key wrap */
2582                 if (!key)
2583                         break;
2584         }
2585 
2586         if (l)
2587                 iter->key = l->key;     /* remember it */
2588         else
2589                 iter->pos = 0;          /* forget it */
2590 
2591         return l;
2592 }
2593 
2594 static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
2595         __acquires(RCU)
2596 {
2597         struct fib_route_iter *iter = seq->private;
2598         struct fib_table *tb;
2599         struct trie *t;
2600 
2601         rcu_read_lock();
2602 
2603         tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
2604         if (!tb)
2605                 return NULL;
2606 
2607         iter->main_tb = tb;
2608         t = (struct trie *)tb->tb_data;
2609         iter->tnode = t->kv;
2610 
2611         if (*pos != 0)
2612                 return fib_route_get_idx(iter, *pos);
2613 
2614         iter->pos = 0;
2615         iter->key = KEY_MAX;
2616 
2617         return SEQ_START_TOKEN;
2618 }
2619 
2620 static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2621 {
2622         struct fib_route_iter *iter = seq->private;
2623         struct key_vector *l = NULL;
2624         t_key key = iter->key + 1;
2625 
2626         ++*pos;
2627 
2628         /* only allow key of 0 for start of sequence */
2629         if ((v == SEQ_START_TOKEN) || key)
2630                 l = leaf_walk_rcu(&iter->tnode, key);
2631 
2632         if (l) {
2633                 iter->key = l->key;
2634                 iter->pos++;
2635         } else {
2636                 iter->pos = 0;
2637         }
2638 
2639         return l;
2640 }
2641 
2642 static void fib_route_seq_stop(struct seq_file *seq, void *v)
2643         __releases(RCU)
2644 {
2645         rcu_read_unlock();
2646 }
2647 
2648 static unsigned int fib_flag_trans(int type, __be32 mask, const struct fib_info *fi)
2649 {
2650         unsigned int flags = 0;
2651 
2652         if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
2653                 flags = RTF_REJECT;
2654         if (fi && fi->fib_nh->nh_gw)
2655                 flags |= RTF_GATEWAY;
2656         if (mask == htonl(0xFFFFFFFF))
2657                 flags |= RTF_HOST;
2658         flags |= RTF_UP;
2659         return flags;
2660 }
2661 
2662 /*
2663  *      This outputs /proc/net/route.
2664  *      The format of the file is not supposed to be changed
2665  *      and needs to be same as fib_hash output to avoid breaking
2666  *      legacy utilities
2667  */
2668 static int fib_route_seq_show(struct seq_file *seq, void *v)
2669 {
2670         struct fib_route_iter *iter = seq->private;
2671         struct fib_table *tb = iter->main_tb;
2672         struct fib_alias *fa;
2673         struct key_vector *l = v;
2674         __be32 prefix;
2675 
2676         if (v == SEQ_START_TOKEN) {
2677                 seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
2678                            "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
2679                            "\tWindow\tIRTT");
2680                 return 0;
2681         }
2682 
2683         prefix = htonl(l->key);
2684 
2685         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2686                 const struct fib_info *fi = fa->fa_info;
2687                 __be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
2688                 unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
2689 
2690                 if ((fa->fa_type == RTN_BROADCAST) ||
2691                     (fa->fa_type == RTN_MULTICAST))
2692                         continue;
2693 
2694                 if (fa->tb_id != tb->tb_id)
2695                         continue;
2696 
2697                 seq_setwidth(seq, 127);
2698 
2699                 if (fi)
2700                         seq_printf(seq,
2701                                    "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
2702                                    "%d\t%08X\t%d\t%u\t%u",
2703                                    fi->fib_dev ? fi->fib_dev->name : "*",
2704                                    prefix,
2705                                    fi->fib_nh->nh_gw, flags, 0, 0,
2706                                    fi->fib_priority,
2707                                    mask,
2708                                    (fi->fib_advmss ?
2709                                     fi->fib_advmss + 40 : 0),
2710                                    fi->fib_window,
2711                                    fi->fib_rtt >> 3);
2712                 else
2713                         seq_printf(seq,
2714                                    "*\t%08X\t%08X\t%04X\t%d\t%u\t"
2715                                    "%d\t%08X\t%d\t%u\t%u",
2716                                    prefix, 0, flags, 0, 0, 0,
2717                                    mask, 0, 0, 0);
2718 
2719                 seq_pad(seq, '\n');
2720         }
2721 
2722         return 0;
2723 }
2724 
2725 static const struct seq_operations fib_route_seq_ops = {
2726         .start  = fib_route_seq_start,
2727         .next   = fib_route_seq_next,
2728         .stop   = fib_route_seq_stop,
2729         .show   = fib_route_seq_show,
2730 };
2731 
2732 int __net_init fib_proc_init(struct net *net)
2733 {
2734         if (!proc_create_net("fib_trie", 0444, net->proc_net, &fib_trie_seq_ops,
2735                         sizeof(struct fib_trie_iter)))
2736                 goto out1;
2737 
2738         if (!proc_create_net_single("fib_triestat", 0444, net->proc_net,
2739                         fib_triestat_seq_show, NULL))
2740                 goto out2;
2741 
2742         if (!proc_create_net("route", 0444, net->proc_net, &fib_route_seq_ops,
2743                         sizeof(struct fib_route_iter)))
2744                 goto out3;
2745 
2746         return 0;
2747 
2748 out3:
2749         remove_proc_entry("fib_triestat", net->proc_net);
2750 out2:
2751         remove_proc_entry("fib_trie", net->proc_net);
2752 out1:
2753         return -ENOMEM;
2754 }
2755 
2756 void __net_exit fib_proc_exit(struct net *net)
2757 {
2758         remove_proc_entry("fib_trie", net->proc_net);
2759         remove_proc_entry("fib_triestat", net->proc_net);
2760         remove_proc_entry("route", net->proc_net);
2761 }
2762 
2763 #endif /* CONFIG_PROC_FS */
2764 

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