Version:  2.0.40 2.2.26 2.4.37 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2

Linux/net/ipv4/fib_trie.c

  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 <asm/uaccess.h>
 54 #include <linux/bitops.h>
 55 #include <linux/types.h>
 56 #include <linux/kernel.h>
 57 #include <linux/mm.h>
 58 #include <linux/string.h>
 59 #include <linux/socket.h>
 60 #include <linux/sockios.h>
 61 #include <linux/errno.h>
 62 #include <linux/in.h>
 63 #include <linux/inet.h>
 64 #include <linux/inetdevice.h>
 65 #include <linux/netdevice.h>
 66 #include <linux/if_arp.h>
 67 #include <linux/proc_fs.h>
 68 #include <linux/rcupdate.h>
 69 #include <linux/skbuff.h>
 70 #include <linux/netlink.h>
 71 #include <linux/init.h>
 72 #include <linux/list.h>
 73 #include <linux/slab.h>
 74 #include <linux/export.h>
 75 #include <linux/vmalloc.h>
 76 #include <net/net_namespace.h>
 77 #include <net/ip.h>
 78 #include <net/protocol.h>
 79 #include <net/route.h>
 80 #include <net/tcp.h>
 81 #include <net/sock.h>
 82 #include <net/ip_fib.h>
 83 #include <net/switchdev.h>
 84 #include "fib_lookup.h"
 85 
 86 #define MAX_STAT_DEPTH 32
 87 
 88 #define KEYLENGTH       (8*sizeof(t_key))
 89 #define KEY_MAX         ((t_key)~0)
 90 
 91 typedef unsigned int t_key;
 92 
 93 #define IS_TRIE(n)      ((n)->pos >= KEYLENGTH)
 94 #define IS_TNODE(n)     ((n)->bits)
 95 #define IS_LEAF(n)      (!(n)->bits)
 96 
 97 struct key_vector {
 98         t_key key;
 99         unsigned char pos;              /* 2log(KEYLENGTH) bits needed */
100         unsigned char bits;             /* 2log(KEYLENGTH) bits needed */
101         unsigned char slen;
102         union {
103                 /* This list pointer if valid if (pos | bits) == 0 (LEAF) */
104                 struct hlist_head leaf;
105                 /* This array is valid if (pos | bits) > 0 (TNODE) */
106                 struct key_vector __rcu *tnode[0];
107         };
108 };
109 
110 struct tnode {
111         struct rcu_head rcu;
112         t_key empty_children;           /* KEYLENGTH bits needed */
113         t_key full_children;            /* KEYLENGTH bits needed */
114         struct key_vector __rcu *parent;
115         struct key_vector kv[1];
116 #define tn_bits kv[0].bits
117 };
118 
119 #define TNODE_SIZE(n)   offsetof(struct tnode, kv[0].tnode[n])
120 #define LEAF_SIZE       TNODE_SIZE(1)
121 
122 #ifdef CONFIG_IP_FIB_TRIE_STATS
123 struct trie_use_stats {
124         unsigned int gets;
125         unsigned int backtrack;
126         unsigned int semantic_match_passed;
127         unsigned int semantic_match_miss;
128         unsigned int null_node_hit;
129         unsigned int resize_node_skipped;
130 };
131 #endif
132 
133 struct trie_stat {
134         unsigned int totdepth;
135         unsigned int maxdepth;
136         unsigned int tnodes;
137         unsigned int leaves;
138         unsigned int nullpointers;
139         unsigned int prefixes;
140         unsigned int nodesizes[MAX_STAT_DEPTH];
141 };
142 
143 struct trie {
144         struct key_vector kv[1];
145 #ifdef CONFIG_IP_FIB_TRIE_STATS
146         struct trie_use_stats __percpu *stats;
147 #endif
148 };
149 
150 static struct key_vector *resize(struct trie *t, struct key_vector *tn);
151 static size_t tnode_free_size;
152 
153 /*
154  * synchronize_rcu after call_rcu for that many pages; it should be especially
155  * useful before resizing the root node with PREEMPT_NONE configs; the value was
156  * obtained experimentally, aiming to avoid visible slowdown.
157  */
158 static const int sync_pages = 128;
159 
160 static struct kmem_cache *fn_alias_kmem __read_mostly;
161 static struct kmem_cache *trie_leaf_kmem __read_mostly;
162 
163 static inline struct tnode *tn_info(struct key_vector *kv)
164 {
165         return container_of(kv, struct tnode, kv[0]);
166 }
167 
168 /* caller must hold RTNL */
169 #define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
170 #define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
171 
172 /* caller must hold RCU read lock or RTNL */
173 #define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
174 #define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
175 
176 /* wrapper for rcu_assign_pointer */
177 static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
178 {
179         if (n)
180                 rcu_assign_pointer(tn_info(n)->parent, tp);
181 }
182 
183 #define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(n)->parent, p)
184 
185 /* This provides us with the number of children in this node, in the case of a
186  * leaf this will return 0 meaning none of the children are accessible.
187  */
188 static inline unsigned long child_length(const struct key_vector *tn)
189 {
190         return (1ul << tn->bits) & ~(1ul);
191 }
192 
193 #define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
194 
195 static inline unsigned long get_index(t_key key, struct key_vector *kv)
196 {
197         unsigned long index = key ^ kv->key;
198 
199         if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
200                 return 0;
201 
202         return index >> kv->pos;
203 }
204 
205 /* To understand this stuff, an understanding of keys and all their bits is
206  * necessary. Every node in the trie has a key associated with it, but not
207  * all of the bits in that key are significant.
208  *
209  * Consider a node 'n' and its parent 'tp'.
210  *
211  * If n is a leaf, every bit in its key is significant. Its presence is
212  * necessitated by path compression, since during a tree traversal (when
213  * searching for a leaf - unless we are doing an insertion) we will completely
214  * ignore all skipped bits we encounter. Thus we need to verify, at the end of
215  * a potentially successful search, that we have indeed been walking the
216  * correct key path.
217  *
218  * Note that we can never "miss" the correct key in the tree if present by
219  * following the wrong path. Path compression ensures that segments of the key
220  * that are the same for all keys with a given prefix are skipped, but the
221  * skipped part *is* identical for each node in the subtrie below the skipped
222  * bit! trie_insert() in this implementation takes care of that.
223  *
224  * if n is an internal node - a 'tnode' here, the various parts of its key
225  * have many different meanings.
226  *
227  * Example:
228  * _________________________________________________________________
229  * | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
230  * -----------------------------------------------------------------
231  *  31  30  29  28  27  26  25  24  23  22  21  20  19  18  17  16
232  *
233  * _________________________________________________________________
234  * | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
235  * -----------------------------------------------------------------
236  *  15  14  13  12  11  10   9   8   7   6   5   4   3   2   1   0
237  *
238  * tp->pos = 22
239  * tp->bits = 3
240  * n->pos = 13
241  * n->bits = 4
242  *
243  * First, let's just ignore the bits that come before the parent tp, that is
244  * the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
245  * point we do not use them for anything.
246  *
247  * The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
248  * index into the parent's child array. That is, they will be used to find
249  * 'n' among tp's children.
250  *
251  * The bits from (n->pos + n->bits) to (tn->pos - 1) - "S" - are skipped bits
252  * for the node n.
253  *
254  * All the bits we have seen so far are significant to the node n. The rest
255  * of the bits are really not needed or indeed known in n->key.
256  *
257  * The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
258  * n's child array, and will of course be different for each child.
259  *
260  * The rest of the bits, from 0 to (n->pos + n->bits), are completely unknown
261  * at this point.
262  */
263 
264 static const int halve_threshold = 25;
265 static const int inflate_threshold = 50;
266 static const int halve_threshold_root = 15;
267 static const int inflate_threshold_root = 30;
268 
269 static void __alias_free_mem(struct rcu_head *head)
270 {
271         struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
272         kmem_cache_free(fn_alias_kmem, fa);
273 }
274 
275 static inline void alias_free_mem_rcu(struct fib_alias *fa)
276 {
277         call_rcu(&fa->rcu, __alias_free_mem);
278 }
279 
280 #define TNODE_KMALLOC_MAX \
281         ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct key_vector *))
282 #define TNODE_VMALLOC_MAX \
283         ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
284 
285 static void __node_free_rcu(struct rcu_head *head)
286 {
287         struct tnode *n = container_of(head, struct tnode, rcu);
288 
289         if (!n->tn_bits)
290                 kmem_cache_free(trie_leaf_kmem, n);
291         else if (n->tn_bits <= TNODE_KMALLOC_MAX)
292                 kfree(n);
293         else
294                 vfree(n);
295 }
296 
297 #define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
298 
299 static struct tnode *tnode_alloc(int bits)
300 {
301         size_t size;
302 
303         /* verify bits is within bounds */
304         if (bits > TNODE_VMALLOC_MAX)
305                 return NULL;
306 
307         /* determine size and verify it is non-zero and didn't overflow */
308         size = TNODE_SIZE(1ul << bits);
309 
310         if (size <= PAGE_SIZE)
311                 return kzalloc(size, GFP_KERNEL);
312         else
313                 return vzalloc(size);
314 }
315 
316 static inline void empty_child_inc(struct key_vector *n)
317 {
318         ++tn_info(n)->empty_children ? : ++tn_info(n)->full_children;
319 }
320 
321 static inline void empty_child_dec(struct key_vector *n)
322 {
323         tn_info(n)->empty_children-- ? : tn_info(n)->full_children--;
324 }
325 
326 static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
327 {
328         struct key_vector *l;
329         struct tnode *kv;
330 
331         kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
332         if (!kv)
333                 return NULL;
334 
335         /* initialize key vector */
336         l = kv->kv;
337         l->key = key;
338         l->pos = 0;
339         l->bits = 0;
340         l->slen = fa->fa_slen;
341 
342         /* link leaf to fib alias */
343         INIT_HLIST_HEAD(&l->leaf);
344         hlist_add_head(&fa->fa_list, &l->leaf);
345 
346         return l;
347 }
348 
349 static struct key_vector *tnode_new(t_key key, int pos, int bits)
350 {
351         unsigned int shift = pos + bits;
352         struct key_vector *tn;
353         struct tnode *tnode;
354 
355         /* verify bits and pos their msb bits clear and values are valid */
356         BUG_ON(!bits || (shift > KEYLENGTH));
357 
358         tnode = tnode_alloc(bits);
359         if (!tnode)
360                 return NULL;
361 
362         pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
363                  sizeof(struct key_vector *) << bits);
364 
365         if (bits == KEYLENGTH)
366                 tnode->full_children = 1;
367         else
368                 tnode->empty_children = 1ul << bits;
369 
370         tn = tnode->kv;
371         tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
372         tn->pos = pos;
373         tn->bits = bits;
374         tn->slen = pos;
375 
376         return tn;
377 }
378 
379 /* Check whether a tnode 'n' is "full", i.e. it is an internal node
380  * and no bits are skipped. See discussion in dyntree paper p. 6
381  */
382 static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
383 {
384         return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
385 }
386 
387 /* Add a child at position i overwriting the old value.
388  * Update the value of full_children and empty_children.
389  */
390 static void put_child(struct key_vector *tn, unsigned long i,
391                       struct key_vector *n)
392 {
393         struct key_vector *chi = get_child(tn, i);
394         int isfull, wasfull;
395 
396         BUG_ON(i >= child_length(tn));
397 
398         /* update emptyChildren, overflow into fullChildren */
399         if (!n && chi)
400                 empty_child_inc(tn);
401         if (n && !chi)
402                 empty_child_dec(tn);
403 
404         /* update fullChildren */
405         wasfull = tnode_full(tn, chi);
406         isfull = tnode_full(tn, n);
407 
408         if (wasfull && !isfull)
409                 tn_info(tn)->full_children--;
410         else if (!wasfull && isfull)
411                 tn_info(tn)->full_children++;
412 
413         if (n && (tn->slen < n->slen))
414                 tn->slen = n->slen;
415 
416         rcu_assign_pointer(tn->tnode[i], n);
417 }
418 
419 static void update_children(struct key_vector *tn)
420 {
421         unsigned long i;
422 
423         /* update all of the child parent pointers */
424         for (i = child_length(tn); i;) {
425                 struct key_vector *inode = get_child(tn, --i);
426 
427                 if (!inode)
428                         continue;
429 
430                 /* Either update the children of a tnode that
431                  * already belongs to us or update the child
432                  * to point to ourselves.
433                  */
434                 if (node_parent(inode) == tn)
435                         update_children(inode);
436                 else
437                         node_set_parent(inode, tn);
438         }
439 }
440 
441 static inline void put_child_root(struct key_vector *tp, t_key key,
442                                   struct key_vector *n)
443 {
444         if (IS_TRIE(tp))
445                 rcu_assign_pointer(tp->tnode[0], n);
446         else
447                 put_child(tp, get_index(key, tp), n);
448 }
449 
450 static inline void tnode_free_init(struct key_vector *tn)
451 {
452         tn_info(tn)->rcu.next = NULL;
453 }
454 
455 static inline void tnode_free_append(struct key_vector *tn,
456                                      struct key_vector *n)
457 {
458         tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
459         tn_info(tn)->rcu.next = &tn_info(n)->rcu;
460 }
461 
462 static void tnode_free(struct key_vector *tn)
463 {
464         struct callback_head *head = &tn_info(tn)->rcu;
465 
466         while (head) {
467                 head = head->next;
468                 tnode_free_size += TNODE_SIZE(1ul << tn->bits);
469                 node_free(tn);
470 
471                 tn = container_of(head, struct tnode, rcu)->kv;
472         }
473 
474         if (tnode_free_size >= PAGE_SIZE * sync_pages) {
475                 tnode_free_size = 0;
476                 synchronize_rcu();
477         }
478 }
479 
480 static struct key_vector *replace(struct trie *t,
481                                   struct key_vector *oldtnode,
482                                   struct key_vector *tn)
483 {
484         struct key_vector *tp = node_parent(oldtnode);
485         unsigned long i;
486 
487         /* setup the parent pointer out of and back into this node */
488         NODE_INIT_PARENT(tn, tp);
489         put_child_root(tp, tn->key, tn);
490 
491         /* update all of the child parent pointers */
492         update_children(tn);
493 
494         /* all pointers should be clean so we are done */
495         tnode_free(oldtnode);
496 
497         /* resize children now that oldtnode is freed */
498         for (i = child_length(tn); i;) {
499                 struct key_vector *inode = get_child(tn, --i);
500 
501                 /* resize child node */
502                 if (tnode_full(tn, inode))
503                         tn = resize(t, inode);
504         }
505 
506         return tp;
507 }
508 
509 static struct key_vector *inflate(struct trie *t,
510                                   struct key_vector *oldtnode)
511 {
512         struct key_vector *tn;
513         unsigned long i;
514         t_key m;
515 
516         pr_debug("In inflate\n");
517 
518         tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
519         if (!tn)
520                 goto notnode;
521 
522         /* prepare oldtnode to be freed */
523         tnode_free_init(oldtnode);
524 
525         /* Assemble all of the pointers in our cluster, in this case that
526          * represents all of the pointers out of our allocated nodes that
527          * point to existing tnodes and the links between our allocated
528          * nodes.
529          */
530         for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
531                 struct key_vector *inode = get_child(oldtnode, --i);
532                 struct key_vector *node0, *node1;
533                 unsigned long j, k;
534 
535                 /* An empty child */
536                 if (!inode)
537                         continue;
538 
539                 /* A leaf or an internal node with skipped bits */
540                 if (!tnode_full(oldtnode, inode)) {
541                         put_child(tn, get_index(inode->key, tn), inode);
542                         continue;
543                 }
544 
545                 /* drop the node in the old tnode free list */
546                 tnode_free_append(oldtnode, inode);
547 
548                 /* An internal node with two children */
549                 if (inode->bits == 1) {
550                         put_child(tn, 2 * i + 1, get_child(inode, 1));
551                         put_child(tn, 2 * i, get_child(inode, 0));
552                         continue;
553                 }
554 
555                 /* We will replace this node 'inode' with two new
556                  * ones, 'node0' and 'node1', each with half of the
557                  * original children. The two new nodes will have
558                  * a position one bit further down the key and this
559                  * means that the "significant" part of their keys
560                  * (see the discussion near the top of this file)
561                  * will differ by one bit, which will be "" in
562                  * node0's key and "1" in node1's key. Since we are
563                  * moving the key position by one step, the bit that
564                  * we are moving away from - the bit at position
565                  * (tn->pos) - is the one that will differ between
566                  * node0 and node1. So... we synthesize that bit in the
567                  * two new keys.
568                  */
569                 node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
570                 if (!node1)
571                         goto nomem;
572                 node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
573 
574                 tnode_free_append(tn, node1);
575                 if (!node0)
576                         goto nomem;
577                 tnode_free_append(tn, node0);
578 
579                 /* populate child pointers in new nodes */
580                 for (k = child_length(inode), j = k / 2; j;) {
581                         put_child(node1, --j, get_child(inode, --k));
582                         put_child(node0, j, get_child(inode, j));
583                         put_child(node1, --j, get_child(inode, --k));
584                         put_child(node0, j, get_child(inode, j));
585                 }
586 
587                 /* link new nodes to parent */
588                 NODE_INIT_PARENT(node1, tn);
589                 NODE_INIT_PARENT(node0, tn);
590 
591                 /* link parent to nodes */
592                 put_child(tn, 2 * i + 1, node1);
593                 put_child(tn, 2 * i, node0);
594         }
595 
596         /* setup the parent pointers into and out of this node */
597         return replace(t, oldtnode, tn);
598 nomem:
599         /* all pointers should be clean so we are done */
600         tnode_free(tn);
601 notnode:
602         return NULL;
603 }
604 
605 static struct key_vector *halve(struct trie *t,
606                                 struct key_vector *oldtnode)
607 {
608         struct key_vector *tn;
609         unsigned long i;
610 
611         pr_debug("In halve\n");
612 
613         tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
614         if (!tn)
615                 goto notnode;
616 
617         /* prepare oldtnode to be freed */
618         tnode_free_init(oldtnode);
619 
620         /* Assemble all of the pointers in our cluster, in this case that
621          * represents all of the pointers out of our allocated nodes that
622          * point to existing tnodes and the links between our allocated
623          * nodes.
624          */
625         for (i = child_length(oldtnode); i;) {
626                 struct key_vector *node1 = get_child(oldtnode, --i);
627                 struct key_vector *node0 = get_child(oldtnode, --i);
628                 struct key_vector *inode;
629 
630                 /* At least one of the children is empty */
631                 if (!node1 || !node0) {
632                         put_child(tn, i / 2, node1 ? : node0);
633                         continue;
634                 }
635 
636                 /* Two nonempty children */
637                 inode = tnode_new(node0->key, oldtnode->pos, 1);
638                 if (!inode)
639                         goto nomem;
640                 tnode_free_append(tn, inode);
641 
642                 /* initialize pointers out of node */
643                 put_child(inode, 1, node1);
644                 put_child(inode, 0, node0);
645                 NODE_INIT_PARENT(inode, tn);
646 
647                 /* link parent to node */
648                 put_child(tn, i / 2, inode);
649         }
650 
651         /* setup the parent pointers into and out of this node */
652         return replace(t, oldtnode, tn);
653 nomem:
654         /* all pointers should be clean so we are done */
655         tnode_free(tn);
656 notnode:
657         return NULL;
658 }
659 
660 static struct key_vector *collapse(struct trie *t,
661                                    struct key_vector *oldtnode)
662 {
663         struct key_vector *n, *tp;
664         unsigned long i;
665 
666         /* scan the tnode looking for that one child that might still exist */
667         for (n = NULL, i = child_length(oldtnode); !n && i;)
668                 n = get_child(oldtnode, --i);
669 
670         /* compress one level */
671         tp = node_parent(oldtnode);
672         put_child_root(tp, oldtnode->key, n);
673         node_set_parent(n, tp);
674 
675         /* drop dead node */
676         node_free(oldtnode);
677 
678         return tp;
679 }
680 
681 static unsigned char update_suffix(struct key_vector *tn)
682 {
683         unsigned char slen = tn->pos;
684         unsigned long stride, i;
685 
686         /* search though the list of children looking for nodes that might
687          * have a suffix greater than the one we currently have.  This is
688          * why we start with a stride of 2 since a stride of 1 would
689          * represent the nodes with suffix length equal to tn->pos
690          */
691         for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
692                 struct key_vector *n = get_child(tn, i);
693 
694                 if (!n || (n->slen <= slen))
695                         continue;
696 
697                 /* update stride and slen based on new value */
698                 stride <<= (n->slen - slen);
699                 slen = n->slen;
700                 i &= ~(stride - 1);
701 
702                 /* if slen covers all but the last bit we can stop here
703                  * there will be nothing longer than that since only node
704                  * 0 and 1 << (bits - 1) could have that as their suffix
705                  * length.
706                  */
707                 if ((slen + 1) >= (tn->pos + tn->bits))
708                         break;
709         }
710 
711         tn->slen = slen;
712 
713         return slen;
714 }
715 
716 /* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
717  * the Helsinki University of Technology and Matti Tikkanen of Nokia
718  * Telecommunications, page 6:
719  * "A node is doubled if the ratio of non-empty children to all
720  * children in the *doubled* node is at least 'high'."
721  *
722  * 'high' in this instance is the variable 'inflate_threshold'. It
723  * is expressed as a percentage, so we multiply it with
724  * child_length() and instead of multiplying by 2 (since the
725  * child array will be doubled by inflate()) and multiplying
726  * the left-hand side by 100 (to handle the percentage thing) we
727  * multiply the left-hand side by 50.
728  *
729  * The left-hand side may look a bit weird: child_length(tn)
730  * - tn->empty_children is of course the number of non-null children
731  * in the current node. tn->full_children is the number of "full"
732  * children, that is non-null tnodes with a skip value of 0.
733  * All of those will be doubled in the resulting inflated tnode, so
734  * we just count them one extra time here.
735  *
736  * A clearer way to write this would be:
737  *
738  * to_be_doubled = tn->full_children;
739  * not_to_be_doubled = child_length(tn) - tn->empty_children -
740  *     tn->full_children;
741  *
742  * new_child_length = child_length(tn) * 2;
743  *
744  * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
745  *      new_child_length;
746  * if (new_fill_factor >= inflate_threshold)
747  *
748  * ...and so on, tho it would mess up the while () loop.
749  *
750  * anyway,
751  * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
752  *      inflate_threshold
753  *
754  * avoid a division:
755  * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
756  *      inflate_threshold * new_child_length
757  *
758  * expand not_to_be_doubled and to_be_doubled, and shorten:
759  * 100 * (child_length(tn) - tn->empty_children +
760  *    tn->full_children) >= inflate_threshold * new_child_length
761  *
762  * expand new_child_length:
763  * 100 * (child_length(tn) - tn->empty_children +
764  *    tn->full_children) >=
765  *      inflate_threshold * child_length(tn) * 2
766  *
767  * shorten again:
768  * 50 * (tn->full_children + child_length(tn) -
769  *    tn->empty_children) >= inflate_threshold *
770  *    child_length(tn)
771  *
772  */
773 static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
774 {
775         unsigned long used = child_length(tn);
776         unsigned long threshold = used;
777 
778         /* Keep root node larger */
779         threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
780         used -= tn_info(tn)->empty_children;
781         used += tn_info(tn)->full_children;
782 
783         /* if bits == KEYLENGTH then pos = 0, and will fail below */
784 
785         return (used > 1) && tn->pos && ((50 * used) >= threshold);
786 }
787 
788 static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
789 {
790         unsigned long used = child_length(tn);
791         unsigned long threshold = used;
792 
793         /* Keep root node larger */
794         threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
795         used -= tn_info(tn)->empty_children;
796 
797         /* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
798 
799         return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
800 }
801 
802 static inline bool should_collapse(struct key_vector *tn)
803 {
804         unsigned long used = child_length(tn);
805 
806         used -= tn_info(tn)->empty_children;
807 
808         /* account for bits == KEYLENGTH case */
809         if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
810                 used -= KEY_MAX;
811 
812         /* One child or none, time to drop us from the trie */
813         return used < 2;
814 }
815 
816 #define MAX_WORK 10
817 static struct key_vector *resize(struct trie *t, struct key_vector *tn)
818 {
819 #ifdef CONFIG_IP_FIB_TRIE_STATS
820         struct trie_use_stats __percpu *stats = t->stats;
821 #endif
822         struct key_vector *tp = node_parent(tn);
823         unsigned long cindex = get_index(tn->key, tp);
824         int max_work = MAX_WORK;
825 
826         pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
827                  tn, inflate_threshold, halve_threshold);
828 
829         /* track the tnode via the pointer from the parent instead of
830          * doing it ourselves.  This way we can let RCU fully do its
831          * thing without us interfering
832          */
833         BUG_ON(tn != get_child(tp, cindex));
834 
835         /* Double as long as the resulting node has a number of
836          * nonempty nodes that are above the threshold.
837          */
838         while (should_inflate(tp, tn) && max_work) {
839                 tp = inflate(t, tn);
840                 if (!tp) {
841 #ifdef CONFIG_IP_FIB_TRIE_STATS
842                         this_cpu_inc(stats->resize_node_skipped);
843 #endif
844                         break;
845                 }
846 
847                 max_work--;
848                 tn = get_child(tp, cindex);
849         }
850 
851         /* update parent in case inflate failed */
852         tp = node_parent(tn);
853 
854         /* Return if at least one inflate is run */
855         if (max_work != MAX_WORK)
856                 return tp;
857 
858         /* Halve as long as the number of empty children in this
859          * node is above threshold.
860          */
861         while (should_halve(tp, tn) && max_work) {
862                 tp = halve(t, tn);
863                 if (!tp) {
864 #ifdef CONFIG_IP_FIB_TRIE_STATS
865                         this_cpu_inc(stats->resize_node_skipped);
866 #endif
867                         break;
868                 }
869 
870                 max_work--;
871                 tn = get_child(tp, cindex);
872         }
873 
874         /* Only one child remains */
875         if (should_collapse(tn))
876                 return collapse(t, tn);
877 
878         /* update parent in case halve failed */
879         tp = node_parent(tn);
880 
881         /* Return if at least one deflate was run */
882         if (max_work != MAX_WORK)
883                 return tp;
884 
885         /* push the suffix length to the parent node */
886         if (tn->slen > tn->pos) {
887                 unsigned char slen = update_suffix(tn);
888 
889                 if (slen > tp->slen)
890                         tp->slen = slen;
891         }
892 
893         return tp;
894 }
895 
896 static void leaf_pull_suffix(struct key_vector *tp, struct key_vector *l)
897 {
898         while ((tp->slen > tp->pos) && (tp->slen > l->slen)) {
899                 if (update_suffix(tp) > l->slen)
900                         break;
901                 tp = node_parent(tp);
902         }
903 }
904 
905 static void leaf_push_suffix(struct key_vector *tn, struct key_vector *l)
906 {
907         /* if this is a new leaf then tn will be NULL and we can sort
908          * out parent suffix lengths as a part of trie_rebalance
909          */
910         while (tn->slen < l->slen) {
911                 tn->slen = l->slen;
912                 tn = node_parent(tn);
913         }
914 }
915 
916 /* rcu_read_lock needs to be hold by caller from readside */
917 static struct key_vector *fib_find_node(struct trie *t,
918                                         struct key_vector **tp, u32 key)
919 {
920         struct key_vector *pn, *n = t->kv;
921         unsigned long index = 0;
922 
923         do {
924                 pn = n;
925                 n = get_child_rcu(n, index);
926 
927                 if (!n)
928                         break;
929 
930                 index = get_cindex(key, n);
931 
932                 /* This bit of code is a bit tricky but it combines multiple
933                  * checks into a single check.  The prefix consists of the
934                  * prefix plus zeros for the bits in the cindex. The index
935                  * is the difference between the key and this value.  From
936                  * this we can actually derive several pieces of data.
937                  *   if (index >= (1ul << bits))
938                  *     we have a mismatch in skip bits and failed
939                  *   else
940                  *     we know the value is cindex
941                  *
942                  * This check is safe even if bits == KEYLENGTH due to the
943                  * fact that we can only allocate a node with 32 bits if a
944                  * long is greater than 32 bits.
945                  */
946                 if (index >= (1ul << n->bits)) {
947                         n = NULL;
948                         break;
949                 }
950 
951                 /* keep searching until we find a perfect match leaf or NULL */
952         } while (IS_TNODE(n));
953 
954         *tp = pn;
955 
956         return n;
957 }
958 
959 /* Return the first fib alias matching TOS with
960  * priority less than or equal to PRIO.
961  */
962 static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
963                                         u8 tos, u32 prio, u32 tb_id)
964 {
965         struct fib_alias *fa;
966 
967         if (!fah)
968                 return NULL;
969 
970         hlist_for_each_entry(fa, fah, fa_list) {
971                 if (fa->fa_slen < slen)
972                         continue;
973                 if (fa->fa_slen != slen)
974                         break;
975                 if (fa->tb_id > tb_id)
976                         continue;
977                 if (fa->tb_id != tb_id)
978                         break;
979                 if (fa->fa_tos > tos)
980                         continue;
981                 if (fa->fa_info->fib_priority >= prio || fa->fa_tos < tos)
982                         return fa;
983         }
984 
985         return NULL;
986 }
987 
988 static void trie_rebalance(struct trie *t, struct key_vector *tn)
989 {
990         while (!IS_TRIE(tn))
991                 tn = resize(t, tn);
992 }
993 
994 static int fib_insert_node(struct trie *t, struct key_vector *tp,
995                            struct fib_alias *new, t_key key)
996 {
997         struct key_vector *n, *l;
998 
999         l = leaf_new(key, new);
1000         if (!l)
1001                 goto noleaf;
1002 
1003         /* retrieve child from parent node */
1004         n = get_child(tp, get_index(key, tp));
1005 
1006         /* Case 2: n is a LEAF or a TNODE and the key doesn't match.
1007          *
1008          *  Add a new tnode here
1009          *  first tnode need some special handling
1010          *  leaves us in position for handling as case 3
1011          */
1012         if (n) {
1013                 struct key_vector *tn;
1014 
1015                 tn = tnode_new(key, __fls(key ^ n->key), 1);
1016                 if (!tn)
1017                         goto notnode;
1018 
1019                 /* initialize routes out of node */
1020                 NODE_INIT_PARENT(tn, tp);
1021                 put_child(tn, get_index(key, tn) ^ 1, n);
1022 
1023                 /* start adding routes into the node */
1024                 put_child_root(tp, key, tn);
1025                 node_set_parent(n, tn);
1026 
1027                 /* parent now has a NULL spot where the leaf can go */
1028                 tp = tn;
1029         }
1030 
1031         /* Case 3: n is NULL, and will just insert a new leaf */
1032         NODE_INIT_PARENT(l, tp);
1033         put_child_root(tp, key, l);
1034         trie_rebalance(t, tp);
1035 
1036         return 0;
1037 notnode:
1038         node_free(l);
1039 noleaf:
1040         return -ENOMEM;
1041 }
1042 
1043 static int fib_insert_alias(struct trie *t, struct key_vector *tp,
1044                             struct key_vector *l, struct fib_alias *new,
1045                             struct fib_alias *fa, t_key key)
1046 {
1047         if (!l)
1048                 return fib_insert_node(t, tp, new, key);
1049 
1050         if (fa) {
1051                 hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
1052         } else {
1053                 struct fib_alias *last;
1054 
1055                 hlist_for_each_entry(last, &l->leaf, fa_list) {
1056                         if (new->fa_slen < last->fa_slen)
1057                                 break;
1058                         if ((new->fa_slen == last->fa_slen) &&
1059                             (new->tb_id > last->tb_id))
1060                                 break;
1061                         fa = last;
1062                 }
1063 
1064                 if (fa)
1065                         hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
1066                 else
1067                         hlist_add_head_rcu(&new->fa_list, &l->leaf);
1068         }
1069 
1070         /* if we added to the tail node then we need to update slen */
1071         if (l->slen < new->fa_slen) {
1072                 l->slen = new->fa_slen;
1073                 leaf_push_suffix(tp, l);
1074         }
1075 
1076         return 0;
1077 }
1078 
1079 /* Caller must hold RTNL. */
1080 int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
1081 {
1082         struct trie *t = (struct trie *)tb->tb_data;
1083         struct fib_alias *fa, *new_fa;
1084         struct key_vector *l, *tp;
1085         unsigned int nlflags = 0;
1086         struct fib_info *fi;
1087         u8 plen = cfg->fc_dst_len;
1088         u8 slen = KEYLENGTH - plen;
1089         u8 tos = cfg->fc_tos;
1090         u32 key;
1091         int err;
1092 
1093         if (plen > KEYLENGTH)
1094                 return -EINVAL;
1095 
1096         key = ntohl(cfg->fc_dst);
1097 
1098         pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
1099 
1100         if ((plen < KEYLENGTH) && (key << plen))
1101                 return -EINVAL;
1102 
1103         fi = fib_create_info(cfg);
1104         if (IS_ERR(fi)) {
1105                 err = PTR_ERR(fi);
1106                 goto err;
1107         }
1108 
1109         l = fib_find_node(t, &tp, key);
1110         fa = l ? fib_find_alias(&l->leaf, slen, tos, fi->fib_priority,
1111                                 tb->tb_id) : NULL;
1112 
1113         /* Now fa, if non-NULL, points to the first fib alias
1114          * with the same keys [prefix,tos,priority], if such key already
1115          * exists or to the node before which we will insert new one.
1116          *
1117          * If fa is NULL, we will need to allocate a new one and
1118          * insert to the tail of the section matching the suffix length
1119          * of the new alias.
1120          */
1121 
1122         if (fa && fa->fa_tos == tos &&
1123             fa->fa_info->fib_priority == fi->fib_priority) {
1124                 struct fib_alias *fa_first, *fa_match;
1125 
1126                 err = -EEXIST;
1127                 if (cfg->fc_nlflags & NLM_F_EXCL)
1128                         goto out;
1129 
1130                 /* We have 2 goals:
1131                  * 1. Find exact match for type, scope, fib_info to avoid
1132                  * duplicate routes
1133                  * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
1134                  */
1135                 fa_match = NULL;
1136                 fa_first = fa;
1137                 hlist_for_each_entry_from(fa, fa_list) {
1138                         if ((fa->fa_slen != slen) ||
1139                             (fa->tb_id != tb->tb_id) ||
1140                             (fa->fa_tos != tos))
1141                                 break;
1142                         if (fa->fa_info->fib_priority != fi->fib_priority)
1143                                 break;
1144                         if (fa->fa_type == cfg->fc_type &&
1145                             fa->fa_info == fi) {
1146                                 fa_match = fa;
1147                                 break;
1148                         }
1149                 }
1150 
1151                 if (cfg->fc_nlflags & NLM_F_REPLACE) {
1152                         struct fib_info *fi_drop;
1153                         u8 state;
1154 
1155                         fa = fa_first;
1156                         if (fa_match) {
1157                                 if (fa == fa_match)
1158                                         err = 0;
1159                                 goto out;
1160                         }
1161                         err = -ENOBUFS;
1162                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1163                         if (!new_fa)
1164                                 goto out;
1165 
1166                         fi_drop = fa->fa_info;
1167                         new_fa->fa_tos = fa->fa_tos;
1168                         new_fa->fa_info = fi;
1169                         new_fa->fa_type = cfg->fc_type;
1170                         state = fa->fa_state;
1171                         new_fa->fa_state = state & ~FA_S_ACCESSED;
1172                         new_fa->fa_slen = fa->fa_slen;
1173                         new_fa->tb_id = tb->tb_id;
1174                         new_fa->fa_default = -1;
1175 
1176                         err = switchdev_fib_ipv4_add(key, plen, fi,
1177                                                      new_fa->fa_tos,
1178                                                      cfg->fc_type,
1179                                                      cfg->fc_nlflags,
1180                                                      tb->tb_id);
1181                         if (err) {
1182                                 switchdev_fib_ipv4_abort(fi);
1183                                 kmem_cache_free(fn_alias_kmem, new_fa);
1184                                 goto out;
1185                         }
1186 
1187                         hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
1188 
1189                         alias_free_mem_rcu(fa);
1190 
1191                         fib_release_info(fi_drop);
1192                         if (state & FA_S_ACCESSED)
1193                                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1194                         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
1195                                 tb->tb_id, &cfg->fc_nlinfo, NLM_F_REPLACE);
1196 
1197                         goto succeeded;
1198                 }
1199                 /* Error if we find a perfect match which
1200                  * uses the same scope, type, and nexthop
1201                  * information.
1202                  */
1203                 if (fa_match)
1204                         goto out;
1205 
1206                 if (cfg->fc_nlflags & NLM_F_APPEND)
1207                         nlflags = NLM_F_APPEND;
1208                 else
1209                         fa = fa_first;
1210         }
1211         err = -ENOENT;
1212         if (!(cfg->fc_nlflags & NLM_F_CREATE))
1213                 goto out;
1214 
1215         err = -ENOBUFS;
1216         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1217         if (!new_fa)
1218                 goto out;
1219 
1220         new_fa->fa_info = fi;
1221         new_fa->fa_tos = tos;
1222         new_fa->fa_type = cfg->fc_type;
1223         new_fa->fa_state = 0;
1224         new_fa->fa_slen = slen;
1225         new_fa->tb_id = tb->tb_id;
1226         new_fa->fa_default = -1;
1227 
1228         /* (Optionally) offload fib entry to switch hardware. */
1229         err = switchdev_fib_ipv4_add(key, plen, fi, tos, cfg->fc_type,
1230                                      cfg->fc_nlflags, tb->tb_id);
1231         if (err) {
1232                 switchdev_fib_ipv4_abort(fi);
1233                 goto out_free_new_fa;
1234         }
1235 
1236         /* Insert new entry to the list. */
1237         err = fib_insert_alias(t, tp, l, new_fa, fa, key);
1238         if (err)
1239                 goto out_sw_fib_del;
1240 
1241         if (!plen)
1242                 tb->tb_num_default++;
1243 
1244         rt_cache_flush(cfg->fc_nlinfo.nl_net);
1245         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
1246                   &cfg->fc_nlinfo, nlflags);
1247 succeeded:
1248         return 0;
1249 
1250 out_sw_fib_del:
1251         switchdev_fib_ipv4_del(key, plen, fi, tos, cfg->fc_type, tb->tb_id);
1252 out_free_new_fa:
1253         kmem_cache_free(fn_alias_kmem, new_fa);
1254 out:
1255         fib_release_info(fi);
1256 err:
1257         return err;
1258 }
1259 
1260 static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
1261 {
1262         t_key prefix = n->key;
1263 
1264         return (key ^ prefix) & (prefix | -prefix);
1265 }
1266 
1267 /* should be called with rcu_read_lock */
1268 int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
1269                      struct fib_result *res, int fib_flags)
1270 {
1271         struct trie *t = (struct trie *) tb->tb_data;
1272 #ifdef CONFIG_IP_FIB_TRIE_STATS
1273         struct trie_use_stats __percpu *stats = t->stats;
1274 #endif
1275         const t_key key = ntohl(flp->daddr);
1276         struct key_vector *n, *pn;
1277         struct fib_alias *fa;
1278         unsigned long index;
1279         t_key cindex;
1280 
1281         pn = t->kv;
1282         cindex = 0;
1283 
1284         n = get_child_rcu(pn, cindex);
1285         if (!n)
1286                 return -EAGAIN;
1287 
1288 #ifdef CONFIG_IP_FIB_TRIE_STATS
1289         this_cpu_inc(stats->gets);
1290 #endif
1291 
1292         /* Step 1: Travel to the longest prefix match in the trie */
1293         for (;;) {
1294                 index = get_cindex(key, n);
1295 
1296                 /* This bit of code is a bit tricky but it combines multiple
1297                  * checks into a single check.  The prefix consists of the
1298                  * prefix plus zeros for the "bits" in the prefix. The index
1299                  * is the difference between the key and this value.  From
1300                  * this we can actually derive several pieces of data.
1301                  *   if (index >= (1ul << bits))
1302                  *     we have a mismatch in skip bits and failed
1303                  *   else
1304                  *     we know the value is cindex
1305                  *
1306                  * This check is safe even if bits == KEYLENGTH due to the
1307                  * fact that we can only allocate a node with 32 bits if a
1308                  * long is greater than 32 bits.
1309                  */
1310                 if (index >= (1ul << n->bits))
1311                         break;
1312 
1313                 /* we have found a leaf. Prefixes have already been compared */
1314                 if (IS_LEAF(n))
1315                         goto found;
1316 
1317                 /* only record pn and cindex if we are going to be chopping
1318                  * bits later.  Otherwise we are just wasting cycles.
1319                  */
1320                 if (n->slen > n->pos) {
1321                         pn = n;
1322                         cindex = index;
1323                 }
1324 
1325                 n = get_child_rcu(n, index);
1326                 if (unlikely(!n))
1327                         goto backtrace;
1328         }
1329 
1330         /* Step 2: Sort out leaves and begin backtracing for longest prefix */
1331         for (;;) {
1332                 /* record the pointer where our next node pointer is stored */
1333                 struct key_vector __rcu **cptr = n->tnode;
1334 
1335                 /* This test verifies that none of the bits that differ
1336                  * between the key and the prefix exist in the region of
1337                  * the lsb and higher in the prefix.
1338                  */
1339                 if (unlikely(prefix_mismatch(key, n)) || (n->slen == n->pos))
1340                         goto backtrace;
1341 
1342                 /* exit out and process leaf */
1343                 if (unlikely(IS_LEAF(n)))
1344                         break;
1345 
1346                 /* Don't bother recording parent info.  Since we are in
1347                  * prefix match mode we will have to come back to wherever
1348                  * we started this traversal anyway
1349                  */
1350 
1351                 while ((n = rcu_dereference(*cptr)) == NULL) {
1352 backtrace:
1353 #ifdef CONFIG_IP_FIB_TRIE_STATS
1354                         if (!n)
1355                                 this_cpu_inc(stats->null_node_hit);
1356 #endif
1357                         /* If we are at cindex 0 there are no more bits for
1358                          * us to strip at this level so we must ascend back
1359                          * up one level to see if there are any more bits to
1360                          * be stripped there.
1361                          */
1362                         while (!cindex) {
1363                                 t_key pkey = pn->key;
1364 
1365                                 /* If we don't have a parent then there is
1366                                  * nothing for us to do as we do not have any
1367                                  * further nodes to parse.
1368                                  */
1369                                 if (IS_TRIE(pn))
1370                                         return -EAGAIN;
1371 #ifdef CONFIG_IP_FIB_TRIE_STATS
1372                                 this_cpu_inc(stats->backtrack);
1373 #endif
1374                                 /* Get Child's index */
1375                                 pn = node_parent_rcu(pn);
1376                                 cindex = get_index(pkey, pn);
1377                         }
1378 
1379                         /* strip the least significant bit from the cindex */
1380                         cindex &= cindex - 1;
1381 
1382                         /* grab pointer for next child node */
1383                         cptr = &pn->tnode[cindex];
1384                 }
1385         }
1386 
1387 found:
1388         /* this line carries forward the xor from earlier in the function */
1389         index = key ^ n->key;
1390 
1391         /* Step 3: Process the leaf, if that fails fall back to backtracing */
1392         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
1393                 struct fib_info *fi = fa->fa_info;
1394                 int nhsel, err;
1395 
1396                 if ((index >= (1ul << fa->fa_slen)) &&
1397                     ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen != KEYLENGTH)))
1398                         continue;
1399                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1400                         continue;
1401                 if (fi->fib_dead)
1402                         continue;
1403                 if (fa->fa_info->fib_scope < flp->flowi4_scope)
1404                         continue;
1405                 fib_alias_accessed(fa);
1406                 err = fib_props[fa->fa_type].error;
1407                 if (unlikely(err < 0)) {
1408 #ifdef CONFIG_IP_FIB_TRIE_STATS
1409                         this_cpu_inc(stats->semantic_match_passed);
1410 #endif
1411                         return err;
1412                 }
1413                 if (fi->fib_flags & RTNH_F_DEAD)
1414                         continue;
1415                 for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
1416                         const struct fib_nh *nh = &fi->fib_nh[nhsel];
1417                         struct in_device *in_dev = __in_dev_get_rcu(nh->nh_dev);
1418 
1419                         if (nh->nh_flags & RTNH_F_DEAD)
1420                                 continue;
1421                         if (in_dev &&
1422                             IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1423                             nh->nh_flags & RTNH_F_LINKDOWN &&
1424                             !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
1425                                 continue;
1426                         if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif)
1427                                 continue;
1428 
1429                         if (!(fib_flags & FIB_LOOKUP_NOREF))
1430                                 atomic_inc(&fi->fib_clntref);
1431 
1432                         res->prefixlen = KEYLENGTH - fa->fa_slen;
1433                         res->nh_sel = nhsel;
1434                         res->type = fa->fa_type;
1435                         res->scope = fi->fib_scope;
1436                         res->fi = fi;
1437                         res->table = tb;
1438                         res->fa_head = &n->leaf;
1439 #ifdef CONFIG_IP_FIB_TRIE_STATS
1440                         this_cpu_inc(stats->semantic_match_passed);
1441 #endif
1442                         return err;
1443                 }
1444         }
1445 #ifdef CONFIG_IP_FIB_TRIE_STATS
1446         this_cpu_inc(stats->semantic_match_miss);
1447 #endif
1448         goto backtrace;
1449 }
1450 EXPORT_SYMBOL_GPL(fib_table_lookup);
1451 
1452 static void fib_remove_alias(struct trie *t, struct key_vector *tp,
1453                              struct key_vector *l, struct fib_alias *old)
1454 {
1455         /* record the location of the previous list_info entry */
1456         struct hlist_node **pprev = old->fa_list.pprev;
1457         struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
1458 
1459         /* remove the fib_alias from the list */
1460         hlist_del_rcu(&old->fa_list);
1461 
1462         /* if we emptied the list this leaf will be freed and we can sort
1463          * out parent suffix lengths as a part of trie_rebalance
1464          */
1465         if (hlist_empty(&l->leaf)) {
1466                 put_child_root(tp, l->key, NULL);
1467                 node_free(l);
1468                 trie_rebalance(t, tp);
1469                 return;
1470         }
1471 
1472         /* only access fa if it is pointing at the last valid hlist_node */
1473         if (*pprev)
1474                 return;
1475 
1476         /* update the trie with the latest suffix length */
1477         l->slen = fa->fa_slen;
1478         leaf_pull_suffix(tp, l);
1479 }
1480 
1481 /* Caller must hold RTNL. */
1482 int fib_table_delete(struct fib_table *tb, struct fib_config *cfg)
1483 {
1484         struct trie *t = (struct trie *) tb->tb_data;
1485         struct fib_alias *fa, *fa_to_delete;
1486         struct key_vector *l, *tp;
1487         u8 plen = cfg->fc_dst_len;
1488         u8 slen = KEYLENGTH - plen;
1489         u8 tos = cfg->fc_tos;
1490         u32 key;
1491 
1492         if (plen > KEYLENGTH)
1493                 return -EINVAL;
1494 
1495         key = ntohl(cfg->fc_dst);
1496 
1497         if ((plen < KEYLENGTH) && (key << plen))
1498                 return -EINVAL;
1499 
1500         l = fib_find_node(t, &tp, key);
1501         if (!l)
1502                 return -ESRCH;
1503 
1504         fa = fib_find_alias(&l->leaf, slen, tos, 0, tb->tb_id);
1505         if (!fa)
1506                 return -ESRCH;
1507 
1508         pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
1509 
1510         fa_to_delete = NULL;
1511         hlist_for_each_entry_from(fa, fa_list) {
1512                 struct fib_info *fi = fa->fa_info;
1513 
1514                 if ((fa->fa_slen != slen) ||
1515                     (fa->tb_id != tb->tb_id) ||
1516                     (fa->fa_tos != tos))
1517                         break;
1518 
1519                 if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
1520                     (cfg->fc_scope == RT_SCOPE_NOWHERE ||
1521                      fa->fa_info->fib_scope == cfg->fc_scope) &&
1522                     (!cfg->fc_prefsrc ||
1523                      fi->fib_prefsrc == cfg->fc_prefsrc) &&
1524                     (!cfg->fc_protocol ||
1525                      fi->fib_protocol == cfg->fc_protocol) &&
1526                     fib_nh_match(cfg, fi) == 0) {
1527                         fa_to_delete = fa;
1528                         break;
1529                 }
1530         }
1531 
1532         if (!fa_to_delete)
1533                 return -ESRCH;
1534 
1535         switchdev_fib_ipv4_del(key, plen, fa_to_delete->fa_info, tos,
1536                                cfg->fc_type, tb->tb_id);
1537 
1538         rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
1539                   &cfg->fc_nlinfo, 0);
1540 
1541         if (!plen)
1542                 tb->tb_num_default--;
1543 
1544         fib_remove_alias(t, tp, l, fa_to_delete);
1545 
1546         if (fa_to_delete->fa_state & FA_S_ACCESSED)
1547                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1548 
1549         fib_release_info(fa_to_delete->fa_info);
1550         alias_free_mem_rcu(fa_to_delete);
1551         return 0;
1552 }
1553 
1554 /* Scan for the next leaf starting at the provided key value */
1555 static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
1556 {
1557         struct key_vector *pn, *n = *tn;
1558         unsigned long cindex;
1559 
1560         /* this loop is meant to try and find the key in the trie */
1561         do {
1562                 /* record parent and next child index */
1563                 pn = n;
1564                 cindex = key ? get_index(key, pn) : 0;
1565 
1566                 if (cindex >> pn->bits)
1567                         break;
1568 
1569                 /* descend into the next child */
1570                 n = get_child_rcu(pn, cindex++);
1571                 if (!n)
1572                         break;
1573 
1574                 /* guarantee forward progress on the keys */
1575                 if (IS_LEAF(n) && (n->key >= key))
1576                         goto found;
1577         } while (IS_TNODE(n));
1578 
1579         /* this loop will search for the next leaf with a greater key */
1580         while (!IS_TRIE(pn)) {
1581                 /* if we exhausted the parent node we will need to climb */
1582                 if (cindex >= (1ul << pn->bits)) {
1583                         t_key pkey = pn->key;
1584 
1585                         pn = node_parent_rcu(pn);
1586                         cindex = get_index(pkey, pn) + 1;
1587                         continue;
1588                 }
1589 
1590                 /* grab the next available node */
1591                 n = get_child_rcu(pn, cindex++);
1592                 if (!n)
1593                         continue;
1594 
1595                 /* no need to compare keys since we bumped the index */
1596                 if (IS_LEAF(n))
1597                         goto found;
1598 
1599                 /* Rescan start scanning in new node */
1600                 pn = n;
1601                 cindex = 0;
1602         }
1603 
1604         *tn = pn;
1605         return NULL; /* Root of trie */
1606 found:
1607         /* if we are at the limit for keys just return NULL for the tnode */
1608         *tn = pn;
1609         return n;
1610 }
1611 
1612 static void fib_trie_free(struct fib_table *tb)
1613 {
1614         struct trie *t = (struct trie *)tb->tb_data;
1615         struct key_vector *pn = t->kv;
1616         unsigned long cindex = 1;
1617         struct hlist_node *tmp;
1618         struct fib_alias *fa;
1619 
1620         /* walk trie in reverse order and free everything */
1621         for (;;) {
1622                 struct key_vector *n;
1623 
1624                 if (!(cindex--)) {
1625                         t_key pkey = pn->key;
1626 
1627                         if (IS_TRIE(pn))
1628                                 break;
1629 
1630                         n = pn;
1631                         pn = node_parent(pn);
1632 
1633                         /* drop emptied tnode */
1634                         put_child_root(pn, n->key, NULL);
1635                         node_free(n);
1636 
1637                         cindex = get_index(pkey, pn);
1638 
1639                         continue;
1640                 }
1641 
1642                 /* grab the next available node */
1643                 n = get_child(pn, cindex);
1644                 if (!n)
1645                         continue;
1646 
1647                 if (IS_TNODE(n)) {
1648                         /* record pn and cindex for leaf walking */
1649                         pn = n;
1650                         cindex = 1ul << n->bits;
1651 
1652                         continue;
1653                 }
1654 
1655                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1656                         hlist_del_rcu(&fa->fa_list);
1657                         alias_free_mem_rcu(fa);
1658                 }
1659 
1660                 put_child_root(pn, n->key, NULL);
1661                 node_free(n);
1662         }
1663 
1664 #ifdef CONFIG_IP_FIB_TRIE_STATS
1665         free_percpu(t->stats);
1666 #endif
1667         kfree(tb);
1668 }
1669 
1670 struct fib_table *fib_trie_unmerge(struct fib_table *oldtb)
1671 {
1672         struct trie *ot = (struct trie *)oldtb->tb_data;
1673         struct key_vector *l, *tp = ot->kv;
1674         struct fib_table *local_tb;
1675         struct fib_alias *fa;
1676         struct trie *lt;
1677         t_key key = 0;
1678 
1679         if (oldtb->tb_data == oldtb->__data)
1680                 return oldtb;
1681 
1682         local_tb = fib_trie_table(RT_TABLE_LOCAL, NULL);
1683         if (!local_tb)
1684                 return NULL;
1685 
1686         lt = (struct trie *)local_tb->tb_data;
1687 
1688         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1689                 struct key_vector *local_l = NULL, *local_tp;
1690 
1691                 hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1692                         struct fib_alias *new_fa;
1693 
1694                         if (local_tb->tb_id != fa->tb_id)
1695                                 continue;
1696 
1697                         /* clone fa for new local table */
1698                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1699                         if (!new_fa)
1700                                 goto out;
1701 
1702                         memcpy(new_fa, fa, sizeof(*fa));
1703 
1704                         /* insert clone into table */
1705                         if (!local_l)
1706                                 local_l = fib_find_node(lt, &local_tp, l->key);
1707 
1708                         if (fib_insert_alias(lt, local_tp, local_l, new_fa,
1709                                              NULL, l->key))
1710                                 goto out;
1711                 }
1712 
1713                 /* stop loop if key wrapped back to 0 */
1714                 key = l->key + 1;
1715                 if (key < l->key)
1716                         break;
1717         }
1718 
1719         return local_tb;
1720 out:
1721         fib_trie_free(local_tb);
1722 
1723         return NULL;
1724 }
1725 
1726 /* Caller must hold RTNL */
1727 void fib_table_flush_external(struct fib_table *tb)
1728 {
1729         struct trie *t = (struct trie *)tb->tb_data;
1730         struct key_vector *pn = t->kv;
1731         unsigned long cindex = 1;
1732         struct hlist_node *tmp;
1733         struct fib_alias *fa;
1734 
1735         /* walk trie in reverse order */
1736         for (;;) {
1737                 unsigned char slen = 0;
1738                 struct key_vector *n;
1739 
1740                 if (!(cindex--)) {
1741                         t_key pkey = pn->key;
1742 
1743                         /* cannot resize the trie vector */
1744                         if (IS_TRIE(pn))
1745                                 break;
1746 
1747                         /* resize completed node */
1748                         pn = resize(t, pn);
1749                         cindex = get_index(pkey, pn);
1750 
1751                         continue;
1752                 }
1753 
1754                 /* grab the next available node */
1755                 n = get_child(pn, cindex);
1756                 if (!n)
1757                         continue;
1758 
1759                 if (IS_TNODE(n)) {
1760                         /* record pn and cindex for leaf walking */
1761                         pn = n;
1762                         cindex = 1ul << n->bits;
1763 
1764                         continue;
1765                 }
1766 
1767                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1768                         struct fib_info *fi = fa->fa_info;
1769 
1770                         /* if alias was cloned to local then we just
1771                          * need to remove the local copy from main
1772                          */
1773                         if (tb->tb_id != fa->tb_id) {
1774                                 hlist_del_rcu(&fa->fa_list);
1775                                 alias_free_mem_rcu(fa);
1776                                 continue;
1777                         }
1778 
1779                         /* record local slen */
1780                         slen = fa->fa_slen;
1781 
1782                         if (!fi || !(fi->fib_flags & RTNH_F_OFFLOAD))
1783                                 continue;
1784 
1785                         switchdev_fib_ipv4_del(n->key, KEYLENGTH - fa->fa_slen,
1786                                                fi, fa->fa_tos, fa->fa_type,
1787                                                tb->tb_id);
1788                 }
1789 
1790                 /* update leaf slen */
1791                 n->slen = slen;
1792 
1793                 if (hlist_empty(&n->leaf)) {
1794                         put_child_root(pn, n->key, NULL);
1795                         node_free(n);
1796                 }
1797         }
1798 }
1799 
1800 /* Caller must hold RTNL. */
1801 int fib_table_flush(struct fib_table *tb)
1802 {
1803         struct trie *t = (struct trie *)tb->tb_data;
1804         struct key_vector *pn = t->kv;
1805         unsigned long cindex = 1;
1806         struct hlist_node *tmp;
1807         struct fib_alias *fa;
1808         int found = 0;
1809 
1810         /* walk trie in reverse order */
1811         for (;;) {
1812                 unsigned char slen = 0;
1813                 struct key_vector *n;
1814 
1815                 if (!(cindex--)) {
1816                         t_key pkey = pn->key;
1817 
1818                         /* cannot resize the trie vector */
1819                         if (IS_TRIE(pn))
1820                                 break;
1821 
1822                         /* resize completed node */
1823                         pn = resize(t, pn);
1824                         cindex = get_index(pkey, pn);
1825 
1826                         continue;
1827                 }
1828 
1829                 /* grab the next available node */
1830                 n = get_child(pn, cindex);
1831                 if (!n)
1832                         continue;
1833 
1834                 if (IS_TNODE(n)) {
1835                         /* record pn and cindex for leaf walking */
1836                         pn = n;
1837                         cindex = 1ul << n->bits;
1838 
1839                         continue;
1840                 }
1841 
1842                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1843                         struct fib_info *fi = fa->fa_info;
1844 
1845                         if (!fi || !(fi->fib_flags & RTNH_F_DEAD)) {
1846                                 slen = fa->fa_slen;
1847                                 continue;
1848                         }
1849 
1850                         switchdev_fib_ipv4_del(n->key, KEYLENGTH - fa->fa_slen,
1851                                                fi, fa->fa_tos, fa->fa_type,
1852                                                tb->tb_id);
1853                         hlist_del_rcu(&fa->fa_list);
1854                         fib_release_info(fa->fa_info);
1855                         alias_free_mem_rcu(fa);
1856                         found++;
1857                 }
1858 
1859                 /* update leaf slen */
1860                 n->slen = slen;
1861 
1862                 if (hlist_empty(&n->leaf)) {
1863                         put_child_root(pn, n->key, NULL);
1864                         node_free(n);
1865                 }
1866         }
1867 
1868         pr_debug("trie_flush found=%d\n", found);
1869         return found;
1870 }
1871 
1872 static void __trie_free_rcu(struct rcu_head *head)
1873 {
1874         struct fib_table *tb = container_of(head, struct fib_table, rcu);
1875 #ifdef CONFIG_IP_FIB_TRIE_STATS
1876         struct trie *t = (struct trie *)tb->tb_data;
1877 
1878         if (tb->tb_data == tb->__data)
1879                 free_percpu(t->stats);
1880 #endif /* CONFIG_IP_FIB_TRIE_STATS */
1881         kfree(tb);
1882 }
1883 
1884 void fib_free_table(struct fib_table *tb)
1885 {
1886         call_rcu(&tb->rcu, __trie_free_rcu);
1887 }
1888 
1889 static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
1890                              struct sk_buff *skb, struct netlink_callback *cb)
1891 {
1892         __be32 xkey = htonl(l->key);
1893         struct fib_alias *fa;
1894         int i, s_i;
1895 
1896         s_i = cb->args[4];
1897         i = 0;
1898 
1899         /* rcu_read_lock is hold by caller */
1900         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1901                 if (i < s_i) {
1902                         i++;
1903                         continue;
1904                 }
1905 
1906                 if (tb->tb_id != fa->tb_id) {
1907                         i++;
1908                         continue;
1909                 }
1910 
1911                 if (fib_dump_info(skb, NETLINK_CB(cb->skb).portid,
1912                                   cb->nlh->nlmsg_seq,
1913                                   RTM_NEWROUTE,
1914                                   tb->tb_id,
1915                                   fa->fa_type,
1916                                   xkey,
1917                                   KEYLENGTH - fa->fa_slen,
1918                                   fa->fa_tos,
1919                                   fa->fa_info, NLM_F_MULTI) < 0) {
1920                         cb->args[4] = i;
1921                         return -1;
1922                 }
1923                 i++;
1924         }
1925 
1926         cb->args[4] = i;
1927         return skb->len;
1928 }
1929 
1930 /* rcu_read_lock needs to be hold by caller from readside */
1931 int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
1932                    struct netlink_callback *cb)
1933 {
1934         struct trie *t = (struct trie *)tb->tb_data;
1935         struct key_vector *l, *tp = t->kv;
1936         /* Dump starting at last key.
1937          * Note: 0.0.0.0/0 (ie default) is first key.
1938          */
1939         int count = cb->args[2];
1940         t_key key = cb->args[3];
1941 
1942         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1943                 if (fn_trie_dump_leaf(l, tb, skb, cb) < 0) {
1944                         cb->args[3] = key;
1945                         cb->args[2] = count;
1946                         return -1;
1947                 }
1948 
1949                 ++count;
1950                 key = l->key + 1;
1951 
1952                 memset(&cb->args[4], 0,
1953                        sizeof(cb->args) - 4*sizeof(cb->args[0]));
1954 
1955                 /* stop loop if key wrapped back to 0 */
1956                 if (key < l->key)
1957                         break;
1958         }
1959 
1960         cb->args[3] = key;
1961         cb->args[2] = count;
1962 
1963         return skb->len;
1964 }
1965 
1966 void __init fib_trie_init(void)
1967 {
1968         fn_alias_kmem = kmem_cache_create("ip_fib_alias",
1969                                           sizeof(struct fib_alias),
1970                                           0, SLAB_PANIC, NULL);
1971 
1972         trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
1973                                            LEAF_SIZE,
1974                                            0, SLAB_PANIC, NULL);
1975 }
1976 
1977 struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
1978 {
1979         struct fib_table *tb;
1980         struct trie *t;
1981         size_t sz = sizeof(*tb);
1982 
1983         if (!alias)
1984                 sz += sizeof(struct trie);
1985 
1986         tb = kzalloc(sz, GFP_KERNEL);
1987         if (!tb)
1988                 return NULL;
1989 
1990         tb->tb_id = id;
1991         tb->tb_num_default = 0;
1992         tb->tb_data = (alias ? alias->__data : tb->__data);
1993 
1994         if (alias)
1995                 return tb;
1996 
1997         t = (struct trie *) tb->tb_data;
1998         t->kv[0].pos = KEYLENGTH;
1999         t->kv[0].slen = KEYLENGTH;
2000 #ifdef CONFIG_IP_FIB_TRIE_STATS
2001         t->stats = alloc_percpu(struct trie_use_stats);
2002         if (!t->stats) {
2003                 kfree(tb);
2004                 tb = NULL;
2005         }
2006 #endif
2007 
2008         return tb;
2009 }
2010 
2011 #ifdef CONFIG_PROC_FS
2012 /* Depth first Trie walk iterator */
2013 struct fib_trie_iter {
2014         struct seq_net_private p;
2015         struct fib_table *tb;
2016         struct key_vector *tnode;
2017         unsigned int index;
2018         unsigned int depth;
2019 };
2020 
2021 static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
2022 {
2023         unsigned long cindex = iter->index;
2024         struct key_vector *pn = iter->tnode;
2025         t_key pkey;
2026 
2027         pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
2028                  iter->tnode, iter->index, iter->depth);
2029 
2030         while (!IS_TRIE(pn)) {
2031                 while (cindex < child_length(pn)) {
2032                         struct key_vector *n = get_child_rcu(pn, cindex++);
2033 
2034                         if (!n)
2035                                 continue;
2036 
2037                         if (IS_LEAF(n)) {
2038                                 iter->tnode = pn;
2039                                 iter->index = cindex;
2040                         } else {
2041                                 /* push down one level */
2042                                 iter->tnode = n;
2043                                 iter->index = 0;
2044                                 ++iter->depth;
2045                         }
2046 
2047                         return n;
2048                 }
2049 
2050                 /* Current node exhausted, pop back up */
2051                 pkey = pn->key;
2052                 pn = node_parent_rcu(pn);
2053                 cindex = get_index(pkey, pn) + 1;
2054                 --iter->depth;
2055         }
2056 
2057         /* record root node so further searches know we are done */
2058         iter->tnode = pn;
2059         iter->index = 0;
2060 
2061         return NULL;
2062 }
2063 
2064 static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
2065                                              struct trie *t)
2066 {
2067         struct key_vector *n, *pn;
2068 
2069         if (!t)
2070                 return NULL;
2071 
2072         pn = t->kv;
2073         n = rcu_dereference(pn->tnode[0]);
2074         if (!n)
2075                 return NULL;
2076 
2077         if (IS_TNODE(n)) {
2078                 iter->tnode = n;
2079                 iter->index = 0;
2080                 iter->depth = 1;
2081         } else {
2082                 iter->tnode = pn;
2083                 iter->index = 0;
2084                 iter->depth = 0;
2085         }
2086 
2087         return n;
2088 }
2089 
2090 static void trie_collect_stats(struct trie *t, struct trie_stat *s)
2091 {
2092         struct key_vector *n;
2093         struct fib_trie_iter iter;
2094 
2095         memset(s, 0, sizeof(*s));
2096 
2097         rcu_read_lock();
2098         for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
2099                 if (IS_LEAF(n)) {
2100                         struct fib_alias *fa;
2101 
2102                         s->leaves++;
2103                         s->totdepth += iter.depth;
2104                         if (iter.depth > s->maxdepth)
2105                                 s->maxdepth = iter.depth;
2106 
2107                         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list)
2108                                 ++s->prefixes;
2109                 } else {
2110                         s->tnodes++;
2111                         if (n->bits < MAX_STAT_DEPTH)
2112                                 s->nodesizes[n->bits]++;
2113                         s->nullpointers += tn_info(n)->empty_children;
2114                 }
2115         }
2116         rcu_read_unlock();
2117 }
2118 
2119 /*
2120  *      This outputs /proc/net/fib_triestats
2121  */
2122 static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
2123 {
2124         unsigned int i, max, pointers, bytes, avdepth;
2125 
2126         if (stat->leaves)
2127                 avdepth = stat->totdepth*100 / stat->leaves;
2128         else
2129                 avdepth = 0;
2130 
2131         seq_printf(seq, "\tAver depth:     %u.%02d\n",
2132                    avdepth / 100, avdepth % 100);
2133         seq_printf(seq, "\tMax depth:      %u\n", stat->maxdepth);
2134 
2135         seq_printf(seq, "\tLeaves:         %u\n", stat->leaves);
2136         bytes = LEAF_SIZE * stat->leaves;
2137 
2138         seq_printf(seq, "\tPrefixes:       %u\n", stat->prefixes);
2139         bytes += sizeof(struct fib_alias) * stat->prefixes;
2140 
2141         seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
2142         bytes += TNODE_SIZE(0) * stat->tnodes;
2143 
2144         max = MAX_STAT_DEPTH;
2145         while (max > 0 && stat->nodesizes[max-1] == 0)
2146                 max--;
2147 
2148         pointers = 0;
2149         for (i = 1; i < max; i++)
2150                 if (stat->nodesizes[i] != 0) {
2151                         seq_printf(seq, "  %u: %u",  i, stat->nodesizes[i]);
2152                         pointers += (1<<i) * stat->nodesizes[i];
2153                 }
2154         seq_putc(seq, '\n');
2155         seq_printf(seq, "\tPointers: %u\n", pointers);
2156 
2157         bytes += sizeof(struct key_vector *) * pointers;
2158         seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
2159         seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
2160 }
2161 
2162 #ifdef CONFIG_IP_FIB_TRIE_STATS
2163 static void trie_show_usage(struct seq_file *seq,
2164                             const struct trie_use_stats __percpu *stats)
2165 {
2166         struct trie_use_stats s = { 0 };
2167         int cpu;
2168 
2169         /* loop through all of the CPUs and gather up the stats */
2170         for_each_possible_cpu(cpu) {
2171                 const struct trie_use_stats *pcpu = per_cpu_ptr(stats, cpu);
2172 
2173                 s.gets += pcpu->gets;
2174                 s.backtrack += pcpu->backtrack;
2175                 s.semantic_match_passed += pcpu->semantic_match_passed;
2176                 s.semantic_match_miss += pcpu->semantic_match_miss;
2177                 s.null_node_hit += pcpu->null_node_hit;
2178                 s.resize_node_skipped += pcpu->resize_node_skipped;
2179         }
2180 
2181         seq_printf(seq, "\nCounters:\n---------\n");
2182         seq_printf(seq, "gets = %u\n", s.gets);
2183         seq_printf(seq, "backtracks = %u\n", s.backtrack);
2184         seq_printf(seq, "semantic match passed = %u\n",
2185                    s.semantic_match_passed);
2186         seq_printf(seq, "semantic match miss = %u\n", s.semantic_match_miss);
2187         seq_printf(seq, "null node hit= %u\n", s.null_node_hit);
2188         seq_printf(seq, "skipped node resize = %u\n\n", s.resize_node_skipped);
2189 }
2190 #endif /*  CONFIG_IP_FIB_TRIE_STATS */
2191 
2192 static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
2193 {
2194         if (tb->tb_id == RT_TABLE_LOCAL)
2195                 seq_puts(seq, "Local:\n");
2196         else if (tb->tb_id == RT_TABLE_MAIN)
2197                 seq_puts(seq, "Main:\n");
2198         else
2199                 seq_printf(seq, "Id %d:\n", tb->tb_id);
2200 }
2201 
2202 
2203 static int fib_triestat_seq_show(struct seq_file *seq, void *v)
2204 {
2205         struct net *net = (struct net *)seq->private;
2206         unsigned int h;
2207 
2208         seq_printf(seq,
2209                    "Basic info: size of leaf:"
2210                    " %Zd bytes, size of tnode: %Zd bytes.\n",
2211                    LEAF_SIZE, TNODE_SIZE(0));
2212 
2213         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2214                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2215                 struct fib_table *tb;
2216 
2217                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2218                         struct trie *t = (struct trie *) tb->tb_data;
2219                         struct trie_stat stat;
2220 
2221                         if (!t)
2222                                 continue;
2223 
2224                         fib_table_print(seq, tb);
2225 
2226                         trie_collect_stats(t, &stat);
2227                         trie_show_stats(seq, &stat);
2228 #ifdef CONFIG_IP_FIB_TRIE_STATS
2229                         trie_show_usage(seq, t->stats);
2230 #endif
2231                 }
2232         }
2233 
2234         return 0;
2235 }
2236 
2237 static int fib_triestat_seq_open(struct inode *inode, struct file *file)
2238 {
2239         return single_open_net(inode, file, fib_triestat_seq_show);
2240 }
2241 
2242 static const struct file_operations fib_triestat_fops = {
2243         .owner  = THIS_MODULE,
2244         .open   = fib_triestat_seq_open,
2245         .read   = seq_read,
2246         .llseek = seq_lseek,
2247         .release = single_release_net,
2248 };
2249 
2250 static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
2251 {
2252         struct fib_trie_iter *iter = seq->private;
2253         struct net *net = seq_file_net(seq);
2254         loff_t idx = 0;
2255         unsigned int h;
2256 
2257         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2258                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2259                 struct fib_table *tb;
2260 
2261                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2262                         struct key_vector *n;
2263 
2264                         for (n = fib_trie_get_first(iter,
2265                                                     (struct trie *) tb->tb_data);
2266                              n; n = fib_trie_get_next(iter))
2267                                 if (pos == idx++) {
2268                                         iter->tb = tb;
2269                                         return n;
2270                                 }
2271                 }
2272         }
2273 
2274         return NULL;
2275 }
2276 
2277 static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
2278         __acquires(RCU)
2279 {
2280         rcu_read_lock();
2281         return fib_trie_get_idx(seq, *pos);
2282 }
2283 
2284 static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2285 {
2286         struct fib_trie_iter *iter = seq->private;
2287         struct net *net = seq_file_net(seq);
2288         struct fib_table *tb = iter->tb;
2289         struct hlist_node *tb_node;
2290         unsigned int h;
2291         struct key_vector *n;
2292 
2293         ++*pos;
2294         /* next node in same table */
2295         n = fib_trie_get_next(iter);
2296         if (n)
2297                 return n;
2298 
2299         /* walk rest of this hash chain */
2300         h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
2301         while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
2302                 tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
2303                 n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2304                 if (n)
2305                         goto found;
2306         }
2307 
2308         /* new hash chain */
2309         while (++h < FIB_TABLE_HASHSZ) {
2310                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2311                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2312                         n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2313                         if (n)
2314                                 goto found;
2315                 }
2316         }
2317         return NULL;
2318 
2319 found:
2320         iter->tb = tb;
2321         return n;
2322 }
2323 
2324 static void fib_trie_seq_stop(struct seq_file *seq, void *v)
2325         __releases(RCU)
2326 {
2327         rcu_read_unlock();
2328 }
2329 
2330 static void seq_indent(struct seq_file *seq, int n)
2331 {
2332         while (n-- > 0)
2333                 seq_puts(seq, "   ");
2334 }
2335 
2336 static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
2337 {
2338         switch (s) {
2339         case RT_SCOPE_UNIVERSE: return "universe";
2340         case RT_SCOPE_SITE:     return "site";
2341         case RT_SCOPE_LINK:     return "link";
2342         case RT_SCOPE_HOST:     return "host";
2343         case RT_SCOPE_NOWHERE:  return "nowhere";
2344         default:
2345                 snprintf(buf, len, "scope=%d", s);
2346                 return buf;
2347         }
2348 }
2349 
2350 static const char *const rtn_type_names[__RTN_MAX] = {
2351         [RTN_UNSPEC] = "UNSPEC",
2352         [RTN_UNICAST] = "UNICAST",
2353         [RTN_LOCAL] = "LOCAL",
2354         [RTN_BROADCAST] = "BROADCAST",
2355         [RTN_ANYCAST] = "ANYCAST",
2356         [RTN_MULTICAST] = "MULTICAST",
2357         [RTN_BLACKHOLE] = "BLACKHOLE",
2358         [RTN_UNREACHABLE] = "UNREACHABLE",
2359         [RTN_PROHIBIT] = "PROHIBIT",
2360         [RTN_THROW] = "THROW",
2361         [RTN_NAT] = "NAT",
2362         [RTN_XRESOLVE] = "XRESOLVE",
2363 };
2364 
2365 static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
2366 {
2367         if (t < __RTN_MAX && rtn_type_names[t])
2368                 return rtn_type_names[t];
2369         snprintf(buf, len, "type %u", t);
2370         return buf;
2371 }
2372 
2373 /* Pretty print the trie */
2374 static int fib_trie_seq_show(struct seq_file *seq, void *v)
2375 {
2376         const struct fib_trie_iter *iter = seq->private;
2377         struct key_vector *n = v;
2378 
2379         if (IS_TRIE(node_parent_rcu(n)))
2380                 fib_table_print(seq, iter->tb);
2381 
2382         if (IS_TNODE(n)) {
2383                 __be32 prf = htonl(n->key);
2384 
2385                 seq_indent(seq, iter->depth-1);
2386                 seq_printf(seq, "  +-- %pI4/%zu %u %u %u\n",
2387                            &prf, KEYLENGTH - n->pos - n->bits, n->bits,
2388                            tn_info(n)->full_children,
2389                            tn_info(n)->empty_children);
2390         } else {
2391                 __be32 val = htonl(n->key);
2392                 struct fib_alias *fa;
2393 
2394                 seq_indent(seq, iter->depth);
2395                 seq_printf(seq, "  |-- %pI4\n", &val);
2396 
2397                 hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
2398                         char buf1[32], buf2[32];
2399 
2400                         seq_indent(seq, iter->depth + 1);
2401                         seq_printf(seq, "  /%zu %s %s",
2402                                    KEYLENGTH - fa->fa_slen,
2403                                    rtn_scope(buf1, sizeof(buf1),
2404                                              fa->fa_info->fib_scope),
2405                                    rtn_type(buf2, sizeof(buf2),
2406                                             fa->fa_type));
2407                         if (fa->fa_tos)
2408                                 seq_printf(seq, " tos=%d", fa->fa_tos);
2409                         seq_putc(seq, '\n');
2410                 }
2411         }
2412 
2413         return 0;
2414 }
2415 
2416 static const struct seq_operations fib_trie_seq_ops = {
2417         .start  = fib_trie_seq_start,
2418         .next   = fib_trie_seq_next,
2419         .stop   = fib_trie_seq_stop,
2420         .show   = fib_trie_seq_show,
2421 };
2422 
2423 static int fib_trie_seq_open(struct inode *inode, struct file *file)
2424 {
2425         return seq_open_net(inode, file, &fib_trie_seq_ops,
2426                             sizeof(struct fib_trie_iter));
2427 }
2428 
2429 static const struct file_operations fib_trie_fops = {
2430         .owner  = THIS_MODULE,
2431         .open   = fib_trie_seq_open,
2432         .read   = seq_read,
2433         .llseek = seq_lseek,
2434         .release = seq_release_net,
2435 };
2436 
2437 struct fib_route_iter {
2438         struct seq_net_private p;
2439         struct fib_table *main_tb;
2440         struct key_vector *tnode;
2441         loff_t  pos;
2442         t_key   key;
2443 };
2444 
2445 static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
2446                                             loff_t pos)
2447 {
2448         struct fib_table *tb = iter->main_tb;
2449         struct key_vector *l, **tp = &iter->tnode;
2450         struct trie *t;
2451         t_key key;
2452 
2453         /* use cache location of next-to-find key */
2454         if (iter->pos > 0 && pos >= iter->pos) {
2455                 pos -= iter->pos;
2456                 key = iter->key;
2457         } else {
2458                 t = (struct trie *)tb->tb_data;
2459                 iter->tnode = t->kv;
2460                 iter->pos = 0;
2461                 key = 0;
2462         }
2463 
2464         while ((l = leaf_walk_rcu(tp, key)) != NULL) {
2465                 key = l->key + 1;
2466                 iter->pos++;
2467 
2468                 if (--pos <= 0)
2469                         break;
2470 
2471                 l = NULL;
2472 
2473                 /* handle unlikely case of a key wrap */
2474                 if (!key)
2475                         break;
2476         }
2477 
2478         if (l)
2479                 iter->key = key;        /* remember it */
2480         else
2481                 iter->pos = 0;          /* forget it */
2482 
2483         return l;
2484 }
2485 
2486 static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
2487         __acquires(RCU)
2488 {
2489         struct fib_route_iter *iter = seq->private;
2490         struct fib_table *tb;
2491         struct trie *t;
2492 
2493         rcu_read_lock();
2494 
2495         tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
2496         if (!tb)
2497                 return NULL;
2498 
2499         iter->main_tb = tb;
2500 
2501         if (*pos != 0)
2502                 return fib_route_get_idx(iter, *pos);
2503 
2504         t = (struct trie *)tb->tb_data;
2505         iter->tnode = t->kv;
2506         iter->pos = 0;
2507         iter->key = 0;
2508 
2509         return SEQ_START_TOKEN;
2510 }
2511 
2512 static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2513 {
2514         struct fib_route_iter *iter = seq->private;
2515         struct key_vector *l = NULL;
2516         t_key key = iter->key;
2517 
2518         ++*pos;
2519 
2520         /* only allow key of 0 for start of sequence */
2521         if ((v == SEQ_START_TOKEN) || key)
2522                 l = leaf_walk_rcu(&iter->tnode, key);
2523 
2524         if (l) {
2525                 iter->key = l->key + 1;
2526                 iter->pos++;
2527         } else {
2528                 iter->pos = 0;
2529         }
2530 
2531         return l;
2532 }
2533 
2534 static void fib_route_seq_stop(struct seq_file *seq, void *v)
2535         __releases(RCU)
2536 {
2537         rcu_read_unlock();
2538 }
2539 
2540 static unsigned int fib_flag_trans(int type, __be32 mask, const struct fib_info *fi)
2541 {
2542         unsigned int flags = 0;
2543 
2544         if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
2545                 flags = RTF_REJECT;
2546         if (fi && fi->fib_nh->nh_gw)
2547                 flags |= RTF_GATEWAY;
2548         if (mask == htonl(0xFFFFFFFF))
2549                 flags |= RTF_HOST;
2550         flags |= RTF_UP;
2551         return flags;
2552 }
2553 
2554 /*
2555  *      This outputs /proc/net/route.
2556  *      The format of the file is not supposed to be changed
2557  *      and needs to be same as fib_hash output to avoid breaking
2558  *      legacy utilities
2559  */
2560 static int fib_route_seq_show(struct seq_file *seq, void *v)
2561 {
2562         struct fib_route_iter *iter = seq->private;
2563         struct fib_table *tb = iter->main_tb;
2564         struct fib_alias *fa;
2565         struct key_vector *l = v;
2566         __be32 prefix;
2567 
2568         if (v == SEQ_START_TOKEN) {
2569                 seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
2570                            "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
2571                            "\tWindow\tIRTT");
2572                 return 0;
2573         }
2574 
2575         prefix = htonl(l->key);
2576 
2577         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2578                 const struct fib_info *fi = fa->fa_info;
2579                 __be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
2580                 unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
2581 
2582                 if ((fa->fa_type == RTN_BROADCAST) ||
2583                     (fa->fa_type == RTN_MULTICAST))
2584                         continue;
2585 
2586                 if (fa->tb_id != tb->tb_id)
2587                         continue;
2588 
2589                 seq_setwidth(seq, 127);
2590 
2591                 if (fi)
2592                         seq_printf(seq,
2593                                    "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
2594                                    "%d\t%08X\t%d\t%u\t%u",
2595                                    fi->fib_dev ? fi->fib_dev->name : "*",
2596                                    prefix,
2597                                    fi->fib_nh->nh_gw, flags, 0, 0,
2598                                    fi->fib_priority,
2599                                    mask,
2600                                    (fi->fib_advmss ?
2601                                     fi->fib_advmss + 40 : 0),
2602                                    fi->fib_window,
2603                                    fi->fib_rtt >> 3);
2604                 else
2605                         seq_printf(seq,
2606                                    "*\t%08X\t%08X\t%04X\t%d\t%u\t"
2607                                    "%d\t%08X\t%d\t%u\t%u",
2608                                    prefix, 0, flags, 0, 0, 0,
2609                                    mask, 0, 0, 0);
2610 
2611                 seq_pad(seq, '\n');
2612         }
2613 
2614         return 0;
2615 }
2616 
2617 static const struct seq_operations fib_route_seq_ops = {
2618         .start  = fib_route_seq_start,
2619         .next   = fib_route_seq_next,
2620         .stop   = fib_route_seq_stop,
2621         .show   = fib_route_seq_show,
2622 };
2623 
2624 static int fib_route_seq_open(struct inode *inode, struct file *file)
2625 {
2626         return seq_open_net(inode, file, &fib_route_seq_ops,
2627                             sizeof(struct fib_route_iter));
2628 }
2629 
2630 static const struct file_operations fib_route_fops = {
2631         .owner  = THIS_MODULE,
2632         .open   = fib_route_seq_open,
2633         .read   = seq_read,
2634         .llseek = seq_lseek,
2635         .release = seq_release_net,
2636 };
2637 
2638 int __net_init fib_proc_init(struct net *net)
2639 {
2640         if (!proc_create("fib_trie", S_IRUGO, net->proc_net, &fib_trie_fops))
2641                 goto out1;
2642 
2643         if (!proc_create("fib_triestat", S_IRUGO, net->proc_net,
2644                          &fib_triestat_fops))
2645                 goto out2;
2646 
2647         if (!proc_create("route", S_IRUGO, net->proc_net, &fib_route_fops))
2648                 goto out3;
2649 
2650         return 0;
2651 
2652 out3:
2653         remove_proc_entry("fib_triestat", net->proc_net);
2654 out2:
2655         remove_proc_entry("fib_trie", net->proc_net);
2656 out1:
2657         return -ENOMEM;
2658 }
2659 
2660 void __net_exit fib_proc_exit(struct net *net)
2661 {
2662         remove_proc_entry("fib_trie", net->proc_net);
2663         remove_proc_entry("fib_triestat", net->proc_net);
2664         remove_proc_entry("route", net->proc_net);
2665 }
2666 
2667 #endif /* CONFIG_PROC_FS */
2668 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us