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Linux/net/ipv4/fib_trie.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  *
  4  *   Robert Olsson <robert.olsson@its.uu.se> Uppsala Universitet
  5  *     & Swedish University of Agricultural Sciences.
  6  *
  7  *   Jens Laas <jens.laas@data.slu.se> Swedish University of
  8  *     Agricultural Sciences.
  9  *
 10  *   Hans Liss <hans.liss@its.uu.se>  Uppsala Universitet
 11  *
 12  * This work is based on the LPC-trie which is originally described in:
 13  *
 14  * An experimental study of compression methods for dynamic tries
 15  * Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
 16  * http://www.csc.kth.se/~snilsson/software/dyntrie2/
 17  *
 18  * IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
 19  * IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
 20  *
 21  * Code from fib_hash has been reused which includes the following header:
 22  *
 23  * INET         An implementation of the TCP/IP protocol suite for the LINUX
 24  *              operating system.  INET is implemented using the  BSD Socket
 25  *              interface as the means of communication with the user level.
 26  *
 27  *              IPv4 FIB: lookup engine and maintenance routines.
 28  *
 29  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 30  *
 31  * Substantial contributions to this work comes from:
 32  *
 33  *              David S. Miller, <davem@davemloft.net>
 34  *              Stephen Hemminger <shemminger@osdl.org>
 35  *              Paul E. McKenney <paulmck@us.ibm.com>
 36  *              Patrick McHardy <kaber@trash.net>
 37  */
 38 #include <linux/cache.h>
 39 #include <linux/uaccess.h>
 40 #include <linux/bitops.h>
 41 #include <linux/types.h>
 42 #include <linux/kernel.h>
 43 #include <linux/mm.h>
 44 #include <linux/string.h>
 45 #include <linux/socket.h>
 46 #include <linux/sockios.h>
 47 #include <linux/errno.h>
 48 #include <linux/in.h>
 49 #include <linux/inet.h>
 50 #include <linux/inetdevice.h>
 51 #include <linux/netdevice.h>
 52 #include <linux/if_arp.h>
 53 #include <linux/proc_fs.h>
 54 #include <linux/rcupdate.h>
 55 #include <linux/skbuff.h>
 56 #include <linux/netlink.h>
 57 #include <linux/init.h>
 58 #include <linux/list.h>
 59 #include <linux/slab.h>
 60 #include <linux/export.h>
 61 #include <linux/vmalloc.h>
 62 #include <linux/notifier.h>
 63 #include <net/net_namespace.h>
 64 #include <net/ip.h>
 65 #include <net/protocol.h>
 66 #include <net/route.h>
 67 #include <net/tcp.h>
 68 #include <net/sock.h>
 69 #include <net/ip_fib.h>
 70 #include <net/fib_notifier.h>
 71 #include <trace/events/fib.h>
 72 #include "fib_lookup.h"
 73 
 74 static int call_fib_entry_notifier(struct notifier_block *nb,
 75                                    enum fib_event_type event_type, u32 dst,
 76                                    int dst_len, struct fib_alias *fa,
 77                                    struct netlink_ext_ack *extack)
 78 {
 79         struct fib_entry_notifier_info info = {
 80                 .info.extack = extack,
 81                 .dst = dst,
 82                 .dst_len = dst_len,
 83                 .fi = fa->fa_info,
 84                 .tos = fa->fa_tos,
 85                 .type = fa->fa_type,
 86                 .tb_id = fa->tb_id,
 87         };
 88         return call_fib4_notifier(nb, event_type, &info.info);
 89 }
 90 
 91 static int call_fib_entry_notifiers(struct net *net,
 92                                     enum fib_event_type event_type, u32 dst,
 93                                     int dst_len, struct fib_alias *fa,
 94                                     struct netlink_ext_ack *extack)
 95 {
 96         struct fib_entry_notifier_info info = {
 97                 .info.extack = extack,
 98                 .dst = dst,
 99                 .dst_len = dst_len,
100                 .fi = fa->fa_info,
101                 .tos = fa->fa_tos,
102                 .type = fa->fa_type,
103                 .tb_id = fa->tb_id,
104         };
105         return call_fib4_notifiers(net, event_type, &info.info);
106 }
107 
108 #define MAX_STAT_DEPTH 32
109 
110 #define KEYLENGTH       (8*sizeof(t_key))
111 #define KEY_MAX         ((t_key)~0)
112 
113 typedef unsigned int t_key;
114 
115 #define IS_TRIE(n)      ((n)->pos >= KEYLENGTH)
116 #define IS_TNODE(n)     ((n)->bits)
117 #define IS_LEAF(n)      (!(n)->bits)
118 
119 struct key_vector {
120         t_key key;
121         unsigned char pos;              /* 2log(KEYLENGTH) bits needed */
122         unsigned char bits;             /* 2log(KEYLENGTH) bits needed */
123         unsigned char slen;
124         union {
125                 /* This list pointer if valid if (pos | bits) == 0 (LEAF) */
126                 struct hlist_head leaf;
127                 /* This array is valid if (pos | bits) > 0 (TNODE) */
128                 struct key_vector __rcu *tnode[0];
129         };
130 };
131 
132 struct tnode {
133         struct rcu_head rcu;
134         t_key empty_children;           /* KEYLENGTH bits needed */
135         t_key full_children;            /* KEYLENGTH bits needed */
136         struct key_vector __rcu *parent;
137         struct key_vector kv[1];
138 #define tn_bits kv[0].bits
139 };
140 
141 #define TNODE_SIZE(n)   offsetof(struct tnode, kv[0].tnode[n])
142 #define LEAF_SIZE       TNODE_SIZE(1)
143 
144 #ifdef CONFIG_IP_FIB_TRIE_STATS
145 struct trie_use_stats {
146         unsigned int gets;
147         unsigned int backtrack;
148         unsigned int semantic_match_passed;
149         unsigned int semantic_match_miss;
150         unsigned int null_node_hit;
151         unsigned int resize_node_skipped;
152 };
153 #endif
154 
155 struct trie_stat {
156         unsigned int totdepth;
157         unsigned int maxdepth;
158         unsigned int tnodes;
159         unsigned int leaves;
160         unsigned int nullpointers;
161         unsigned int prefixes;
162         unsigned int nodesizes[MAX_STAT_DEPTH];
163 };
164 
165 struct trie {
166         struct key_vector kv[1];
167 #ifdef CONFIG_IP_FIB_TRIE_STATS
168         struct trie_use_stats __percpu *stats;
169 #endif
170 };
171 
172 static struct key_vector *resize(struct trie *t, struct key_vector *tn);
173 static unsigned int tnode_free_size;
174 
175 /*
176  * synchronize_rcu after call_rcu for outstanding dirty memory; it should be
177  * especially useful before resizing the root node with PREEMPT_NONE configs;
178  * the value was obtained experimentally, aiming to avoid visible slowdown.
179  */
180 unsigned int sysctl_fib_sync_mem = 512 * 1024;
181 unsigned int sysctl_fib_sync_mem_min = 64 * 1024;
182 unsigned int sysctl_fib_sync_mem_max = 64 * 1024 * 1024;
183 
184 static struct kmem_cache *fn_alias_kmem __ro_after_init;
185 static struct kmem_cache *trie_leaf_kmem __ro_after_init;
186 
187 static inline struct tnode *tn_info(struct key_vector *kv)
188 {
189         return container_of(kv, struct tnode, kv[0]);
190 }
191 
192 /* caller must hold RTNL */
193 #define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
194 #define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
195 
196 /* caller must hold RCU read lock or RTNL */
197 #define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
198 #define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
199 
200 /* wrapper for rcu_assign_pointer */
201 static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
202 {
203         if (n)
204                 rcu_assign_pointer(tn_info(n)->parent, tp);
205 }
206 
207 #define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(n)->parent, p)
208 
209 /* This provides us with the number of children in this node, in the case of a
210  * leaf this will return 0 meaning none of the children are accessible.
211  */
212 static inline unsigned long child_length(const struct key_vector *tn)
213 {
214         return (1ul << tn->bits) & ~(1ul);
215 }
216 
217 #define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
218 
219 static inline unsigned long get_index(t_key key, struct key_vector *kv)
220 {
221         unsigned long index = key ^ kv->key;
222 
223         if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
224                 return 0;
225 
226         return index >> kv->pos;
227 }
228 
229 /* To understand this stuff, an understanding of keys and all their bits is
230  * necessary. Every node in the trie has a key associated with it, but not
231  * all of the bits in that key are significant.
232  *
233  * Consider a node 'n' and its parent 'tp'.
234  *
235  * If n is a leaf, every bit in its key is significant. Its presence is
236  * necessitated by path compression, since during a tree traversal (when
237  * searching for a leaf - unless we are doing an insertion) we will completely
238  * ignore all skipped bits we encounter. Thus we need to verify, at the end of
239  * a potentially successful search, that we have indeed been walking the
240  * correct key path.
241  *
242  * Note that we can never "miss" the correct key in the tree if present by
243  * following the wrong path. Path compression ensures that segments of the key
244  * that are the same for all keys with a given prefix are skipped, but the
245  * skipped part *is* identical for each node in the subtrie below the skipped
246  * bit! trie_insert() in this implementation takes care of that.
247  *
248  * if n is an internal node - a 'tnode' here, the various parts of its key
249  * have many different meanings.
250  *
251  * Example:
252  * _________________________________________________________________
253  * | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
254  * -----------------------------------------------------------------
255  *  31  30  29  28  27  26  25  24  23  22  21  20  19  18  17  16
256  *
257  * _________________________________________________________________
258  * | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
259  * -----------------------------------------------------------------
260  *  15  14  13  12  11  10   9   8   7   6   5   4   3   2   1   0
261  *
262  * tp->pos = 22
263  * tp->bits = 3
264  * n->pos = 13
265  * n->bits = 4
266  *
267  * First, let's just ignore the bits that come before the parent tp, that is
268  * the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
269  * point we do not use them for anything.
270  *
271  * The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
272  * index into the parent's child array. That is, they will be used to find
273  * 'n' among tp's children.
274  *
275  * The bits from (n->pos + n->bits) to (tp->pos - 1) - "S" - are skipped bits
276  * for the node n.
277  *
278  * All the bits we have seen so far are significant to the node n. The rest
279  * of the bits are really not needed or indeed known in n->key.
280  *
281  * The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
282  * n's child array, and will of course be different for each child.
283  *
284  * The rest of the bits, from 0 to (n->pos -1) - "u" - are completely unknown
285  * at this point.
286  */
287 
288 static const int halve_threshold = 25;
289 static const int inflate_threshold = 50;
290 static const int halve_threshold_root = 15;
291 static const int inflate_threshold_root = 30;
292 
293 static void __alias_free_mem(struct rcu_head *head)
294 {
295         struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
296         kmem_cache_free(fn_alias_kmem, fa);
297 }
298 
299 static inline void alias_free_mem_rcu(struct fib_alias *fa)
300 {
301         call_rcu(&fa->rcu, __alias_free_mem);
302 }
303 
304 #define TNODE_VMALLOC_MAX \
305         ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
306 
307 static void __node_free_rcu(struct rcu_head *head)
308 {
309         struct tnode *n = container_of(head, struct tnode, rcu);
310 
311         if (!n->tn_bits)
312                 kmem_cache_free(trie_leaf_kmem, n);
313         else
314                 kvfree(n);
315 }
316 
317 #define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
318 
319 static struct tnode *tnode_alloc(int bits)
320 {
321         size_t size;
322 
323         /* verify bits is within bounds */
324         if (bits > TNODE_VMALLOC_MAX)
325                 return NULL;
326 
327         /* determine size and verify it is non-zero and didn't overflow */
328         size = TNODE_SIZE(1ul << bits);
329 
330         if (size <= PAGE_SIZE)
331                 return kzalloc(size, GFP_KERNEL);
332         else
333                 return vzalloc(size);
334 }
335 
336 static inline void empty_child_inc(struct key_vector *n)
337 {
338         tn_info(n)->empty_children++;
339 
340         if (!tn_info(n)->empty_children)
341                 tn_info(n)->full_children++;
342 }
343 
344 static inline void empty_child_dec(struct key_vector *n)
345 {
346         if (!tn_info(n)->empty_children)
347                 tn_info(n)->full_children--;
348 
349         tn_info(n)->empty_children--;
350 }
351 
352 static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
353 {
354         struct key_vector *l;
355         struct tnode *kv;
356 
357         kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
358         if (!kv)
359                 return NULL;
360 
361         /* initialize key vector */
362         l = kv->kv;
363         l->key = key;
364         l->pos = 0;
365         l->bits = 0;
366         l->slen = fa->fa_slen;
367 
368         /* link leaf to fib alias */
369         INIT_HLIST_HEAD(&l->leaf);
370         hlist_add_head(&fa->fa_list, &l->leaf);
371 
372         return l;
373 }
374 
375 static struct key_vector *tnode_new(t_key key, int pos, int bits)
376 {
377         unsigned int shift = pos + bits;
378         struct key_vector *tn;
379         struct tnode *tnode;
380 
381         /* verify bits and pos their msb bits clear and values are valid */
382         BUG_ON(!bits || (shift > KEYLENGTH));
383 
384         tnode = tnode_alloc(bits);
385         if (!tnode)
386                 return NULL;
387 
388         pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
389                  sizeof(struct key_vector *) << bits);
390 
391         if (bits == KEYLENGTH)
392                 tnode->full_children = 1;
393         else
394                 tnode->empty_children = 1ul << bits;
395 
396         tn = tnode->kv;
397         tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
398         tn->pos = pos;
399         tn->bits = bits;
400         tn->slen = pos;
401 
402         return tn;
403 }
404 
405 /* Check whether a tnode 'n' is "full", i.e. it is an internal node
406  * and no bits are skipped. See discussion in dyntree paper p. 6
407  */
408 static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
409 {
410         return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
411 }
412 
413 /* Add a child at position i overwriting the old value.
414  * Update the value of full_children and empty_children.
415  */
416 static void put_child(struct key_vector *tn, unsigned long i,
417                       struct key_vector *n)
418 {
419         struct key_vector *chi = get_child(tn, i);
420         int isfull, wasfull;
421 
422         BUG_ON(i >= child_length(tn));
423 
424         /* update emptyChildren, overflow into fullChildren */
425         if (!n && chi)
426                 empty_child_inc(tn);
427         if (n && !chi)
428                 empty_child_dec(tn);
429 
430         /* update fullChildren */
431         wasfull = tnode_full(tn, chi);
432         isfull = tnode_full(tn, n);
433 
434         if (wasfull && !isfull)
435                 tn_info(tn)->full_children--;
436         else if (!wasfull && isfull)
437                 tn_info(tn)->full_children++;
438 
439         if (n && (tn->slen < n->slen))
440                 tn->slen = n->slen;
441 
442         rcu_assign_pointer(tn->tnode[i], n);
443 }
444 
445 static void update_children(struct key_vector *tn)
446 {
447         unsigned long i;
448 
449         /* update all of the child parent pointers */
450         for (i = child_length(tn); i;) {
451                 struct key_vector *inode = get_child(tn, --i);
452 
453                 if (!inode)
454                         continue;
455 
456                 /* Either update the children of a tnode that
457                  * already belongs to us or update the child
458                  * to point to ourselves.
459                  */
460                 if (node_parent(inode) == tn)
461                         update_children(inode);
462                 else
463                         node_set_parent(inode, tn);
464         }
465 }
466 
467 static inline void put_child_root(struct key_vector *tp, t_key key,
468                                   struct key_vector *n)
469 {
470         if (IS_TRIE(tp))
471                 rcu_assign_pointer(tp->tnode[0], n);
472         else
473                 put_child(tp, get_index(key, tp), n);
474 }
475 
476 static inline void tnode_free_init(struct key_vector *tn)
477 {
478         tn_info(tn)->rcu.next = NULL;
479 }
480 
481 static inline void tnode_free_append(struct key_vector *tn,
482                                      struct key_vector *n)
483 {
484         tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
485         tn_info(tn)->rcu.next = &tn_info(n)->rcu;
486 }
487 
488 static void tnode_free(struct key_vector *tn)
489 {
490         struct callback_head *head = &tn_info(tn)->rcu;
491 
492         while (head) {
493                 head = head->next;
494                 tnode_free_size += TNODE_SIZE(1ul << tn->bits);
495                 node_free(tn);
496 
497                 tn = container_of(head, struct tnode, rcu)->kv;
498         }
499 
500         if (tnode_free_size >= sysctl_fib_sync_mem) {
501                 tnode_free_size = 0;
502                 synchronize_rcu();
503         }
504 }
505 
506 static struct key_vector *replace(struct trie *t,
507                                   struct key_vector *oldtnode,
508                                   struct key_vector *tn)
509 {
510         struct key_vector *tp = node_parent(oldtnode);
511         unsigned long i;
512 
513         /* setup the parent pointer out of and back into this node */
514         NODE_INIT_PARENT(tn, tp);
515         put_child_root(tp, tn->key, tn);
516 
517         /* update all of the child parent pointers */
518         update_children(tn);
519 
520         /* all pointers should be clean so we are done */
521         tnode_free(oldtnode);
522 
523         /* resize children now that oldtnode is freed */
524         for (i = child_length(tn); i;) {
525                 struct key_vector *inode = get_child(tn, --i);
526 
527                 /* resize child node */
528                 if (tnode_full(tn, inode))
529                         tn = resize(t, inode);
530         }
531 
532         return tp;
533 }
534 
535 static struct key_vector *inflate(struct trie *t,
536                                   struct key_vector *oldtnode)
537 {
538         struct key_vector *tn;
539         unsigned long i;
540         t_key m;
541 
542         pr_debug("In inflate\n");
543 
544         tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
545         if (!tn)
546                 goto notnode;
547 
548         /* prepare oldtnode to be freed */
549         tnode_free_init(oldtnode);
550 
551         /* Assemble all of the pointers in our cluster, in this case that
552          * represents all of the pointers out of our allocated nodes that
553          * point to existing tnodes and the links between our allocated
554          * nodes.
555          */
556         for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
557                 struct key_vector *inode = get_child(oldtnode, --i);
558                 struct key_vector *node0, *node1;
559                 unsigned long j, k;
560 
561                 /* An empty child */
562                 if (!inode)
563                         continue;
564 
565                 /* A leaf or an internal node with skipped bits */
566                 if (!tnode_full(oldtnode, inode)) {
567                         put_child(tn, get_index(inode->key, tn), inode);
568                         continue;
569                 }
570 
571                 /* drop the node in the old tnode free list */
572                 tnode_free_append(oldtnode, inode);
573 
574                 /* An internal node with two children */
575                 if (inode->bits == 1) {
576                         put_child(tn, 2 * i + 1, get_child(inode, 1));
577                         put_child(tn, 2 * i, get_child(inode, 0));
578                         continue;
579                 }
580 
581                 /* We will replace this node 'inode' with two new
582                  * ones, 'node0' and 'node1', each with half of the
583                  * original children. The two new nodes will have
584                  * a position one bit further down the key and this
585                  * means that the "significant" part of their keys
586                  * (see the discussion near the top of this file)
587                  * will differ by one bit, which will be "" in
588                  * node0's key and "1" in node1's key. Since we are
589                  * moving the key position by one step, the bit that
590                  * we are moving away from - the bit at position
591                  * (tn->pos) - is the one that will differ between
592                  * node0 and node1. So... we synthesize that bit in the
593                  * two new keys.
594                  */
595                 node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
596                 if (!node1)
597                         goto nomem;
598                 node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
599 
600                 tnode_free_append(tn, node1);
601                 if (!node0)
602                         goto nomem;
603                 tnode_free_append(tn, node0);
604 
605                 /* populate child pointers in new nodes */
606                 for (k = child_length(inode), j = k / 2; j;) {
607                         put_child(node1, --j, get_child(inode, --k));
608                         put_child(node0, j, get_child(inode, j));
609                         put_child(node1, --j, get_child(inode, --k));
610                         put_child(node0, j, get_child(inode, j));
611                 }
612 
613                 /* link new nodes to parent */
614                 NODE_INIT_PARENT(node1, tn);
615                 NODE_INIT_PARENT(node0, tn);
616 
617                 /* link parent to nodes */
618                 put_child(tn, 2 * i + 1, node1);
619                 put_child(tn, 2 * i, node0);
620         }
621 
622         /* setup the parent pointers into and out of this node */
623         return replace(t, oldtnode, tn);
624 nomem:
625         /* all pointers should be clean so we are done */
626         tnode_free(tn);
627 notnode:
628         return NULL;
629 }
630 
631 static struct key_vector *halve(struct trie *t,
632                                 struct key_vector *oldtnode)
633 {
634         struct key_vector *tn;
635         unsigned long i;
636 
637         pr_debug("In halve\n");
638 
639         tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
640         if (!tn)
641                 goto notnode;
642 
643         /* prepare oldtnode to be freed */
644         tnode_free_init(oldtnode);
645 
646         /* Assemble all of the pointers in our cluster, in this case that
647          * represents all of the pointers out of our allocated nodes that
648          * point to existing tnodes and the links between our allocated
649          * nodes.
650          */
651         for (i = child_length(oldtnode); i;) {
652                 struct key_vector *node1 = get_child(oldtnode, --i);
653                 struct key_vector *node0 = get_child(oldtnode, --i);
654                 struct key_vector *inode;
655 
656                 /* At least one of the children is empty */
657                 if (!node1 || !node0) {
658                         put_child(tn, i / 2, node1 ? : node0);
659                         continue;
660                 }
661 
662                 /* Two nonempty children */
663                 inode = tnode_new(node0->key, oldtnode->pos, 1);
664                 if (!inode)
665                         goto nomem;
666                 tnode_free_append(tn, inode);
667 
668                 /* initialize pointers out of node */
669                 put_child(inode, 1, node1);
670                 put_child(inode, 0, node0);
671                 NODE_INIT_PARENT(inode, tn);
672 
673                 /* link parent to node */
674                 put_child(tn, i / 2, inode);
675         }
676 
677         /* setup the parent pointers into and out of this node */
678         return replace(t, oldtnode, tn);
679 nomem:
680         /* all pointers should be clean so we are done */
681         tnode_free(tn);
682 notnode:
683         return NULL;
684 }
685 
686 static struct key_vector *collapse(struct trie *t,
687                                    struct key_vector *oldtnode)
688 {
689         struct key_vector *n, *tp;
690         unsigned long i;
691 
692         /* scan the tnode looking for that one child that might still exist */
693         for (n = NULL, i = child_length(oldtnode); !n && i;)
694                 n = get_child(oldtnode, --i);
695 
696         /* compress one level */
697         tp = node_parent(oldtnode);
698         put_child_root(tp, oldtnode->key, n);
699         node_set_parent(n, tp);
700 
701         /* drop dead node */
702         node_free(oldtnode);
703 
704         return tp;
705 }
706 
707 static unsigned char update_suffix(struct key_vector *tn)
708 {
709         unsigned char slen = tn->pos;
710         unsigned long stride, i;
711         unsigned char slen_max;
712 
713         /* only vector 0 can have a suffix length greater than or equal to
714          * tn->pos + tn->bits, the second highest node will have a suffix
715          * length at most of tn->pos + tn->bits - 1
716          */
717         slen_max = min_t(unsigned char, tn->pos + tn->bits - 1, tn->slen);
718 
719         /* search though the list of children looking for nodes that might
720          * have a suffix greater than the one we currently have.  This is
721          * why we start with a stride of 2 since a stride of 1 would
722          * represent the nodes with suffix length equal to tn->pos
723          */
724         for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
725                 struct key_vector *n = get_child(tn, i);
726 
727                 if (!n || (n->slen <= slen))
728                         continue;
729 
730                 /* update stride and slen based on new value */
731                 stride <<= (n->slen - slen);
732                 slen = n->slen;
733                 i &= ~(stride - 1);
734 
735                 /* stop searching if we have hit the maximum possible value */
736                 if (slen >= slen_max)
737                         break;
738         }
739 
740         tn->slen = slen;
741 
742         return slen;
743 }
744 
745 /* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
746  * the Helsinki University of Technology and Matti Tikkanen of Nokia
747  * Telecommunications, page 6:
748  * "A node is doubled if the ratio of non-empty children to all
749  * children in the *doubled* node is at least 'high'."
750  *
751  * 'high' in this instance is the variable 'inflate_threshold'. It
752  * is expressed as a percentage, so we multiply it with
753  * child_length() and instead of multiplying by 2 (since the
754  * child array will be doubled by inflate()) and multiplying
755  * the left-hand side by 100 (to handle the percentage thing) we
756  * multiply the left-hand side by 50.
757  *
758  * The left-hand side may look a bit weird: child_length(tn)
759  * - tn->empty_children is of course the number of non-null children
760  * in the current node. tn->full_children is the number of "full"
761  * children, that is non-null tnodes with a skip value of 0.
762  * All of those will be doubled in the resulting inflated tnode, so
763  * we just count them one extra time here.
764  *
765  * A clearer way to write this would be:
766  *
767  * to_be_doubled = tn->full_children;
768  * not_to_be_doubled = child_length(tn) - tn->empty_children -
769  *     tn->full_children;
770  *
771  * new_child_length = child_length(tn) * 2;
772  *
773  * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
774  *      new_child_length;
775  * if (new_fill_factor >= inflate_threshold)
776  *
777  * ...and so on, tho it would mess up the while () loop.
778  *
779  * anyway,
780  * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
781  *      inflate_threshold
782  *
783  * avoid a division:
784  * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
785  *      inflate_threshold * new_child_length
786  *
787  * expand not_to_be_doubled and to_be_doubled, and shorten:
788  * 100 * (child_length(tn) - tn->empty_children +
789  *    tn->full_children) >= inflate_threshold * new_child_length
790  *
791  * expand new_child_length:
792  * 100 * (child_length(tn) - tn->empty_children +
793  *    tn->full_children) >=
794  *      inflate_threshold * child_length(tn) * 2
795  *
796  * shorten again:
797  * 50 * (tn->full_children + child_length(tn) -
798  *    tn->empty_children) >= inflate_threshold *
799  *    child_length(tn)
800  *
801  */
802 static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
803 {
804         unsigned long used = child_length(tn);
805         unsigned long threshold = used;
806 
807         /* Keep root node larger */
808         threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
809         used -= tn_info(tn)->empty_children;
810         used += tn_info(tn)->full_children;
811 
812         /* if bits == KEYLENGTH then pos = 0, and will fail below */
813 
814         return (used > 1) && tn->pos && ((50 * used) >= threshold);
815 }
816 
817 static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
818 {
819         unsigned long used = child_length(tn);
820         unsigned long threshold = used;
821 
822         /* Keep root node larger */
823         threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
824         used -= tn_info(tn)->empty_children;
825 
826         /* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
827 
828         return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
829 }
830 
831 static inline bool should_collapse(struct key_vector *tn)
832 {
833         unsigned long used = child_length(tn);
834 
835         used -= tn_info(tn)->empty_children;
836 
837         /* account for bits == KEYLENGTH case */
838         if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
839                 used -= KEY_MAX;
840 
841         /* One child or none, time to drop us from the trie */
842         return used < 2;
843 }
844 
845 #define MAX_WORK 10
846 static struct key_vector *resize(struct trie *t, struct key_vector *tn)
847 {
848 #ifdef CONFIG_IP_FIB_TRIE_STATS
849         struct trie_use_stats __percpu *stats = t->stats;
850 #endif
851         struct key_vector *tp = node_parent(tn);
852         unsigned long cindex = get_index(tn->key, tp);
853         int max_work = MAX_WORK;
854 
855         pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
856                  tn, inflate_threshold, halve_threshold);
857 
858         /* track the tnode via the pointer from the parent instead of
859          * doing it ourselves.  This way we can let RCU fully do its
860          * thing without us interfering
861          */
862         BUG_ON(tn != get_child(tp, cindex));
863 
864         /* Double as long as the resulting node has a number of
865          * nonempty nodes that are above the threshold.
866          */
867         while (should_inflate(tp, tn) && max_work) {
868                 tp = inflate(t, tn);
869                 if (!tp) {
870 #ifdef CONFIG_IP_FIB_TRIE_STATS
871                         this_cpu_inc(stats->resize_node_skipped);
872 #endif
873                         break;
874                 }
875 
876                 max_work--;
877                 tn = get_child(tp, cindex);
878         }
879 
880         /* update parent in case inflate failed */
881         tp = node_parent(tn);
882 
883         /* Return if at least one inflate is run */
884         if (max_work != MAX_WORK)
885                 return tp;
886 
887         /* Halve as long as the number of empty children in this
888          * node is above threshold.
889          */
890         while (should_halve(tp, tn) && max_work) {
891                 tp = halve(t, tn);
892                 if (!tp) {
893 #ifdef CONFIG_IP_FIB_TRIE_STATS
894                         this_cpu_inc(stats->resize_node_skipped);
895 #endif
896                         break;
897                 }
898 
899                 max_work--;
900                 tn = get_child(tp, cindex);
901         }
902 
903         /* Only one child remains */
904         if (should_collapse(tn))
905                 return collapse(t, tn);
906 
907         /* update parent in case halve failed */
908         return node_parent(tn);
909 }
910 
911 static void node_pull_suffix(struct key_vector *tn, unsigned char slen)
912 {
913         unsigned char node_slen = tn->slen;
914 
915         while ((node_slen > tn->pos) && (node_slen > slen)) {
916                 slen = update_suffix(tn);
917                 if (node_slen == slen)
918                         break;
919 
920                 tn = node_parent(tn);
921                 node_slen = tn->slen;
922         }
923 }
924 
925 static void node_push_suffix(struct key_vector *tn, unsigned char slen)
926 {
927         while (tn->slen < slen) {
928                 tn->slen = slen;
929                 tn = node_parent(tn);
930         }
931 }
932 
933 /* rcu_read_lock needs to be hold by caller from readside */
934 static struct key_vector *fib_find_node(struct trie *t,
935                                         struct key_vector **tp, u32 key)
936 {
937         struct key_vector *pn, *n = t->kv;
938         unsigned long index = 0;
939 
940         do {
941                 pn = n;
942                 n = get_child_rcu(n, index);
943 
944                 if (!n)
945                         break;
946 
947                 index = get_cindex(key, n);
948 
949                 /* This bit of code is a bit tricky but it combines multiple
950                  * checks into a single check.  The prefix consists of the
951                  * prefix plus zeros for the bits in the cindex. The index
952                  * is the difference between the key and this value.  From
953                  * this we can actually derive several pieces of data.
954                  *   if (index >= (1ul << bits))
955                  *     we have a mismatch in skip bits and failed
956                  *   else
957                  *     we know the value is cindex
958                  *
959                  * This check is safe even if bits == KEYLENGTH due to the
960                  * fact that we can only allocate a node with 32 bits if a
961                  * long is greater than 32 bits.
962                  */
963                 if (index >= (1ul << n->bits)) {
964                         n = NULL;
965                         break;
966                 }
967 
968                 /* keep searching until we find a perfect match leaf or NULL */
969         } while (IS_TNODE(n));
970 
971         *tp = pn;
972 
973         return n;
974 }
975 
976 /* Return the first fib alias matching TOS with
977  * priority less than or equal to PRIO.
978  * If 'find_first' is set, return the first matching
979  * fib alias, regardless of TOS and priority.
980  */
981 static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
982                                         u8 tos, u32 prio, u32 tb_id,
983                                         bool find_first)
984 {
985         struct fib_alias *fa;
986 
987         if (!fah)
988                 return NULL;
989 
990         hlist_for_each_entry(fa, fah, fa_list) {
991                 if (fa->fa_slen < slen)
992                         continue;
993                 if (fa->fa_slen != slen)
994                         break;
995                 if (fa->tb_id > tb_id)
996                         continue;
997                 if (fa->tb_id != tb_id)
998                         break;
999                 if (find_first)
1000                         return fa;
1001                 if (fa->fa_tos > tos)
1002                         continue;
1003                 if (fa->fa_info->fib_priority >= prio || fa->fa_tos < tos)
1004                         return fa;
1005         }
1006 
1007         return NULL;
1008 }
1009 
1010 static struct fib_alias *
1011 fib_find_matching_alias(struct net *net, const struct fib_rt_info *fri)
1012 {
1013         u8 slen = KEYLENGTH - fri->dst_len;
1014         struct key_vector *l, *tp;
1015         struct fib_table *tb;
1016         struct fib_alias *fa;
1017         struct trie *t;
1018 
1019         tb = fib_get_table(net, fri->tb_id);
1020         if (!tb)
1021                 return NULL;
1022 
1023         t = (struct trie *)tb->tb_data;
1024         l = fib_find_node(t, &tp, be32_to_cpu(fri->dst));
1025         if (!l)
1026                 return NULL;
1027 
1028         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1029                 if (fa->fa_slen == slen && fa->tb_id == fri->tb_id &&
1030                     fa->fa_tos == fri->tos && fa->fa_info == fri->fi &&
1031                     fa->fa_type == fri->type)
1032                         return fa;
1033         }
1034 
1035         return NULL;
1036 }
1037 
1038 void fib_alias_hw_flags_set(struct net *net, const struct fib_rt_info *fri)
1039 {
1040         struct fib_alias *fa_match;
1041 
1042         rcu_read_lock();
1043 
1044         fa_match = fib_find_matching_alias(net, fri);
1045         if (!fa_match)
1046                 goto out;
1047 
1048         fa_match->offload = fri->offload;
1049         fa_match->trap = fri->trap;
1050 
1051 out:
1052         rcu_read_unlock();
1053 }
1054 EXPORT_SYMBOL_GPL(fib_alias_hw_flags_set);
1055 
1056 static void trie_rebalance(struct trie *t, struct key_vector *tn)
1057 {
1058         while (!IS_TRIE(tn))
1059                 tn = resize(t, tn);
1060 }
1061 
1062 static int fib_insert_node(struct trie *t, struct key_vector *tp,
1063                            struct fib_alias *new, t_key key)
1064 {
1065         struct key_vector *n, *l;
1066 
1067         l = leaf_new(key, new);
1068         if (!l)
1069                 goto noleaf;
1070 
1071         /* retrieve child from parent node */
1072         n = get_child(tp, get_index(key, tp));
1073 
1074         /* Case 2: n is a LEAF or a TNODE and the key doesn't match.
1075          *
1076          *  Add a new tnode here
1077          *  first tnode need some special handling
1078          *  leaves us in position for handling as case 3
1079          */
1080         if (n) {
1081                 struct key_vector *tn;
1082 
1083                 tn = tnode_new(key, __fls(key ^ n->key), 1);
1084                 if (!tn)
1085                         goto notnode;
1086 
1087                 /* initialize routes out of node */
1088                 NODE_INIT_PARENT(tn, tp);
1089                 put_child(tn, get_index(key, tn) ^ 1, n);
1090 
1091                 /* start adding routes into the node */
1092                 put_child_root(tp, key, tn);
1093                 node_set_parent(n, tn);
1094 
1095                 /* parent now has a NULL spot where the leaf can go */
1096                 tp = tn;
1097         }
1098 
1099         /* Case 3: n is NULL, and will just insert a new leaf */
1100         node_push_suffix(tp, new->fa_slen);
1101         NODE_INIT_PARENT(l, tp);
1102         put_child_root(tp, key, l);
1103         trie_rebalance(t, tp);
1104 
1105         return 0;
1106 notnode:
1107         node_free(l);
1108 noleaf:
1109         return -ENOMEM;
1110 }
1111 
1112 static int fib_insert_alias(struct trie *t, struct key_vector *tp,
1113                             struct key_vector *l, struct fib_alias *new,
1114                             struct fib_alias *fa, t_key key)
1115 {
1116         if (!l)
1117                 return fib_insert_node(t, tp, new, key);
1118 
1119         if (fa) {
1120                 hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
1121         } else {
1122                 struct fib_alias *last;
1123 
1124                 hlist_for_each_entry(last, &l->leaf, fa_list) {
1125                         if (new->fa_slen < last->fa_slen)
1126                                 break;
1127                         if ((new->fa_slen == last->fa_slen) &&
1128                             (new->tb_id > last->tb_id))
1129                                 break;
1130                         fa = last;
1131                 }
1132 
1133                 if (fa)
1134                         hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
1135                 else
1136                         hlist_add_head_rcu(&new->fa_list, &l->leaf);
1137         }
1138 
1139         /* if we added to the tail node then we need to update slen */
1140         if (l->slen < new->fa_slen) {
1141                 l->slen = new->fa_slen;
1142                 node_push_suffix(tp, new->fa_slen);
1143         }
1144 
1145         return 0;
1146 }
1147 
1148 static bool fib_valid_key_len(u32 key, u8 plen, struct netlink_ext_ack *extack)
1149 {
1150         if (plen > KEYLENGTH) {
1151                 NL_SET_ERR_MSG(extack, "Invalid prefix length");
1152                 return false;
1153         }
1154 
1155         if ((plen < KEYLENGTH) && (key << plen)) {
1156                 NL_SET_ERR_MSG(extack,
1157                                "Invalid prefix for given prefix length");
1158                 return false;
1159         }
1160 
1161         return true;
1162 }
1163 
1164 static void fib_remove_alias(struct trie *t, struct key_vector *tp,
1165                              struct key_vector *l, struct fib_alias *old);
1166 
1167 /* Caller must hold RTNL. */
1168 int fib_table_insert(struct net *net, struct fib_table *tb,
1169                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1170 {
1171         struct trie *t = (struct trie *)tb->tb_data;
1172         struct fib_alias *fa, *new_fa;
1173         struct key_vector *l, *tp;
1174         u16 nlflags = NLM_F_EXCL;
1175         struct fib_info *fi;
1176         u8 plen = cfg->fc_dst_len;
1177         u8 slen = KEYLENGTH - plen;
1178         u8 tos = cfg->fc_tos;
1179         u32 key;
1180         int err;
1181 
1182         key = ntohl(cfg->fc_dst);
1183 
1184         if (!fib_valid_key_len(key, plen, extack))
1185                 return -EINVAL;
1186 
1187         pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
1188 
1189         fi = fib_create_info(cfg, extack);
1190         if (IS_ERR(fi)) {
1191                 err = PTR_ERR(fi);
1192                 goto err;
1193         }
1194 
1195         l = fib_find_node(t, &tp, key);
1196         fa = l ? fib_find_alias(&l->leaf, slen, tos, fi->fib_priority,
1197                                 tb->tb_id, false) : NULL;
1198 
1199         /* Now fa, if non-NULL, points to the first fib alias
1200          * with the same keys [prefix,tos,priority], if such key already
1201          * exists or to the node before which we will insert new one.
1202          *
1203          * If fa is NULL, we will need to allocate a new one and
1204          * insert to the tail of the section matching the suffix length
1205          * of the new alias.
1206          */
1207 
1208         if (fa && fa->fa_tos == tos &&
1209             fa->fa_info->fib_priority == fi->fib_priority) {
1210                 struct fib_alias *fa_first, *fa_match;
1211 
1212                 err = -EEXIST;
1213                 if (cfg->fc_nlflags & NLM_F_EXCL)
1214                         goto out;
1215 
1216                 nlflags &= ~NLM_F_EXCL;
1217 
1218                 /* We have 2 goals:
1219                  * 1. Find exact match for type, scope, fib_info to avoid
1220                  * duplicate routes
1221                  * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
1222                  */
1223                 fa_match = NULL;
1224                 fa_first = fa;
1225                 hlist_for_each_entry_from(fa, fa_list) {
1226                         if ((fa->fa_slen != slen) ||
1227                             (fa->tb_id != tb->tb_id) ||
1228                             (fa->fa_tos != tos))
1229                                 break;
1230                         if (fa->fa_info->fib_priority != fi->fib_priority)
1231                                 break;
1232                         if (fa->fa_type == cfg->fc_type &&
1233                             fa->fa_info == fi) {
1234                                 fa_match = fa;
1235                                 break;
1236                         }
1237                 }
1238 
1239                 if (cfg->fc_nlflags & NLM_F_REPLACE) {
1240                         struct fib_info *fi_drop;
1241                         u8 state;
1242 
1243                         nlflags |= NLM_F_REPLACE;
1244                         fa = fa_first;
1245                         if (fa_match) {
1246                                 if (fa == fa_match)
1247                                         err = 0;
1248                                 goto out;
1249                         }
1250                         err = -ENOBUFS;
1251                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1252                         if (!new_fa)
1253                                 goto out;
1254 
1255                         fi_drop = fa->fa_info;
1256                         new_fa->fa_tos = fa->fa_tos;
1257                         new_fa->fa_info = fi;
1258                         new_fa->fa_type = cfg->fc_type;
1259                         state = fa->fa_state;
1260                         new_fa->fa_state = state & ~FA_S_ACCESSED;
1261                         new_fa->fa_slen = fa->fa_slen;
1262                         new_fa->tb_id = tb->tb_id;
1263                         new_fa->fa_default = -1;
1264                         new_fa->offload = 0;
1265                         new_fa->trap = 0;
1266 
1267                         hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
1268 
1269                         if (fib_find_alias(&l->leaf, fa->fa_slen, 0, 0,
1270                                            tb->tb_id, true) == new_fa) {
1271                                 enum fib_event_type fib_event;
1272 
1273                                 fib_event = FIB_EVENT_ENTRY_REPLACE;
1274                                 err = call_fib_entry_notifiers(net, fib_event,
1275                                                                key, plen,
1276                                                                new_fa, extack);
1277                                 if (err) {
1278                                         hlist_replace_rcu(&new_fa->fa_list,
1279                                                           &fa->fa_list);
1280                                         goto out_free_new_fa;
1281                                 }
1282                         }
1283 
1284                         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
1285                                   tb->tb_id, &cfg->fc_nlinfo, nlflags);
1286 
1287                         alias_free_mem_rcu(fa);
1288 
1289                         fib_release_info(fi_drop);
1290                         if (state & FA_S_ACCESSED)
1291                                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1292 
1293                         goto succeeded;
1294                 }
1295                 /* Error if we find a perfect match which
1296                  * uses the same scope, type, and nexthop
1297                  * information.
1298                  */
1299                 if (fa_match)
1300                         goto out;
1301 
1302                 if (cfg->fc_nlflags & NLM_F_APPEND)
1303                         nlflags |= NLM_F_APPEND;
1304                 else
1305                         fa = fa_first;
1306         }
1307         err = -ENOENT;
1308         if (!(cfg->fc_nlflags & NLM_F_CREATE))
1309                 goto out;
1310 
1311         nlflags |= NLM_F_CREATE;
1312         err = -ENOBUFS;
1313         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1314         if (!new_fa)
1315                 goto out;
1316 
1317         new_fa->fa_info = fi;
1318         new_fa->fa_tos = tos;
1319         new_fa->fa_type = cfg->fc_type;
1320         new_fa->fa_state = 0;
1321         new_fa->fa_slen = slen;
1322         new_fa->tb_id = tb->tb_id;
1323         new_fa->fa_default = -1;
1324         new_fa->offload = 0;
1325         new_fa->trap = 0;
1326 
1327         /* Insert new entry to the list. */
1328         err = fib_insert_alias(t, tp, l, new_fa, fa, key);
1329         if (err)
1330                 goto out_free_new_fa;
1331 
1332         /* The alias was already inserted, so the node must exist. */
1333         l = l ? l : fib_find_node(t, &tp, key);
1334         if (WARN_ON_ONCE(!l))
1335                 goto out_free_new_fa;
1336 
1337         if (fib_find_alias(&l->leaf, new_fa->fa_slen, 0, 0, tb->tb_id, true) ==
1338             new_fa) {
1339                 enum fib_event_type fib_event;
1340 
1341                 fib_event = FIB_EVENT_ENTRY_REPLACE;
1342                 err = call_fib_entry_notifiers(net, fib_event, key, plen,
1343                                                new_fa, extack);
1344                 if (err)
1345                         goto out_remove_new_fa;
1346         }
1347 
1348         if (!plen)
1349                 tb->tb_num_default++;
1350 
1351         rt_cache_flush(cfg->fc_nlinfo.nl_net);
1352         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
1353                   &cfg->fc_nlinfo, nlflags);
1354 succeeded:
1355         return 0;
1356 
1357 out_remove_new_fa:
1358         fib_remove_alias(t, tp, l, new_fa);
1359 out_free_new_fa:
1360         kmem_cache_free(fn_alias_kmem, new_fa);
1361 out:
1362         fib_release_info(fi);
1363 err:
1364         return err;
1365 }
1366 
1367 static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
1368 {
1369         t_key prefix = n->key;
1370 
1371         return (key ^ prefix) & (prefix | -prefix);
1372 }
1373 
1374 bool fib_lookup_good_nhc(const struct fib_nh_common *nhc, int fib_flags,
1375                          const struct flowi4 *flp)
1376 {
1377         if (nhc->nhc_flags & RTNH_F_DEAD)
1378                 return false;
1379 
1380         if (ip_ignore_linkdown(nhc->nhc_dev) &&
1381             nhc->nhc_flags & RTNH_F_LINKDOWN &&
1382             !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
1383                 return false;
1384 
1385         if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) {
1386                 if (flp->flowi4_oif &&
1387                     flp->flowi4_oif != nhc->nhc_oif)
1388                         return false;
1389         }
1390 
1391         return true;
1392 }
1393 
1394 /* should be called with rcu_read_lock */
1395 int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
1396                      struct fib_result *res, int fib_flags)
1397 {
1398         struct trie *t = (struct trie *) tb->tb_data;
1399 #ifdef CONFIG_IP_FIB_TRIE_STATS
1400         struct trie_use_stats __percpu *stats = t->stats;
1401 #endif
1402         const t_key key = ntohl(flp->daddr);
1403         struct key_vector *n, *pn;
1404         struct fib_alias *fa;
1405         unsigned long index;
1406         t_key cindex;
1407 
1408         pn = t->kv;
1409         cindex = 0;
1410 
1411         n = get_child_rcu(pn, cindex);
1412         if (!n) {
1413                 trace_fib_table_lookup(tb->tb_id, flp, NULL, -EAGAIN);
1414                 return -EAGAIN;
1415         }
1416 
1417 #ifdef CONFIG_IP_FIB_TRIE_STATS
1418         this_cpu_inc(stats->gets);
1419 #endif
1420 
1421         /* Step 1: Travel to the longest prefix match in the trie */
1422         for (;;) {
1423                 index = get_cindex(key, n);
1424 
1425                 /* This bit of code is a bit tricky but it combines multiple
1426                  * checks into a single check.  The prefix consists of the
1427                  * prefix plus zeros for the "bits" in the prefix. The index
1428                  * is the difference between the key and this value.  From
1429                  * this we can actually derive several pieces of data.
1430                  *   if (index >= (1ul << bits))
1431                  *     we have a mismatch in skip bits and failed
1432                  *   else
1433                  *     we know the value is cindex
1434                  *
1435                  * This check is safe even if bits == KEYLENGTH due to the
1436                  * fact that we can only allocate a node with 32 bits if a
1437                  * long is greater than 32 bits.
1438                  */
1439                 if (index >= (1ul << n->bits))
1440                         break;
1441 
1442                 /* we have found a leaf. Prefixes have already been compared */
1443                 if (IS_LEAF(n))
1444                         goto found;
1445 
1446                 /* only record pn and cindex if we are going to be chopping
1447                  * bits later.  Otherwise we are just wasting cycles.
1448                  */
1449                 if (n->slen > n->pos) {
1450                         pn = n;
1451                         cindex = index;
1452                 }
1453 
1454                 n = get_child_rcu(n, index);
1455                 if (unlikely(!n))
1456                         goto backtrace;
1457         }
1458 
1459         /* Step 2: Sort out leaves and begin backtracing for longest prefix */
1460         for (;;) {
1461                 /* record the pointer where our next node pointer is stored */
1462                 struct key_vector __rcu **cptr = n->tnode;
1463 
1464                 /* This test verifies that none of the bits that differ
1465                  * between the key and the prefix exist in the region of
1466                  * the lsb and higher in the prefix.
1467                  */
1468                 if (unlikely(prefix_mismatch(key, n)) || (n->slen == n->pos))
1469                         goto backtrace;
1470 
1471                 /* exit out and process leaf */
1472                 if (unlikely(IS_LEAF(n)))
1473                         break;
1474 
1475                 /* Don't bother recording parent info.  Since we are in
1476                  * prefix match mode we will have to come back to wherever
1477                  * we started this traversal anyway
1478                  */
1479 
1480                 while ((n = rcu_dereference(*cptr)) == NULL) {
1481 backtrace:
1482 #ifdef CONFIG_IP_FIB_TRIE_STATS
1483                         if (!n)
1484                                 this_cpu_inc(stats->null_node_hit);
1485 #endif
1486                         /* If we are at cindex 0 there are no more bits for
1487                          * us to strip at this level so we must ascend back
1488                          * up one level to see if there are any more bits to
1489                          * be stripped there.
1490                          */
1491                         while (!cindex) {
1492                                 t_key pkey = pn->key;
1493 
1494                                 /* If we don't have a parent then there is
1495                                  * nothing for us to do as we do not have any
1496                                  * further nodes to parse.
1497                                  */
1498                                 if (IS_TRIE(pn)) {
1499                                         trace_fib_table_lookup(tb->tb_id, flp,
1500                                                                NULL, -EAGAIN);
1501                                         return -EAGAIN;
1502                                 }
1503 #ifdef CONFIG_IP_FIB_TRIE_STATS
1504                                 this_cpu_inc(stats->backtrack);
1505 #endif
1506                                 /* Get Child's index */
1507                                 pn = node_parent_rcu(pn);
1508                                 cindex = get_index(pkey, pn);
1509                         }
1510 
1511                         /* strip the least significant bit from the cindex */
1512                         cindex &= cindex - 1;
1513 
1514                         /* grab pointer for next child node */
1515                         cptr = &pn->tnode[cindex];
1516                 }
1517         }
1518 
1519 found:
1520         /* this line carries forward the xor from earlier in the function */
1521         index = key ^ n->key;
1522 
1523         /* Step 3: Process the leaf, if that fails fall back to backtracing */
1524         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
1525                 struct fib_info *fi = fa->fa_info;
1526                 struct fib_nh_common *nhc;
1527                 int nhsel, err;
1528 
1529                 if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) {
1530                         if (index >= (1ul << fa->fa_slen))
1531                                 continue;
1532                 }
1533                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1534                         continue;
1535                 if (fi->fib_dead)
1536                         continue;
1537                 if (fa->fa_info->fib_scope < flp->flowi4_scope)
1538                         continue;
1539                 fib_alias_accessed(fa);
1540                 err = fib_props[fa->fa_type].error;
1541                 if (unlikely(err < 0)) {
1542 out_reject:
1543 #ifdef CONFIG_IP_FIB_TRIE_STATS
1544                         this_cpu_inc(stats->semantic_match_passed);
1545 #endif
1546                         trace_fib_table_lookup(tb->tb_id, flp, NULL, err);
1547                         return err;
1548                 }
1549                 if (fi->fib_flags & RTNH_F_DEAD)
1550                         continue;
1551 
1552                 if (unlikely(fi->nh)) {
1553                         if (nexthop_is_blackhole(fi->nh)) {
1554                                 err = fib_props[RTN_BLACKHOLE].error;
1555                                 goto out_reject;
1556                         }
1557 
1558                         nhc = nexthop_get_nhc_lookup(fi->nh, fib_flags, flp,
1559                                                      &nhsel);
1560                         if (nhc)
1561                                 goto set_result;
1562                         goto miss;
1563                 }
1564 
1565                 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
1566                         nhc = fib_info_nhc(fi, nhsel);
1567 
1568                         if (!fib_lookup_good_nhc(nhc, fib_flags, flp))
1569                                 continue;
1570 set_result:
1571                         if (!(fib_flags & FIB_LOOKUP_NOREF))
1572                                 refcount_inc(&fi->fib_clntref);
1573 
1574                         res->prefix = htonl(n->key);
1575                         res->prefixlen = KEYLENGTH - fa->fa_slen;
1576                         res->nh_sel = nhsel;
1577                         res->nhc = nhc;
1578                         res->type = fa->fa_type;
1579                         res->scope = fi->fib_scope;
1580                         res->fi = fi;
1581                         res->table = tb;
1582                         res->fa_head = &n->leaf;
1583 #ifdef CONFIG_IP_FIB_TRIE_STATS
1584                         this_cpu_inc(stats->semantic_match_passed);
1585 #endif
1586                         trace_fib_table_lookup(tb->tb_id, flp, nhc, err);
1587 
1588                         return err;
1589                 }
1590         }
1591 miss:
1592 #ifdef CONFIG_IP_FIB_TRIE_STATS
1593         this_cpu_inc(stats->semantic_match_miss);
1594 #endif
1595         goto backtrace;
1596 }
1597 EXPORT_SYMBOL_GPL(fib_table_lookup);
1598 
1599 static void fib_remove_alias(struct trie *t, struct key_vector *tp,
1600                              struct key_vector *l, struct fib_alias *old)
1601 {
1602         /* record the location of the previous list_info entry */
1603         struct hlist_node **pprev = old->fa_list.pprev;
1604         struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
1605 
1606         /* remove the fib_alias from the list */
1607         hlist_del_rcu(&old->fa_list);
1608 
1609         /* if we emptied the list this leaf will be freed and we can sort
1610          * out parent suffix lengths as a part of trie_rebalance
1611          */
1612         if (hlist_empty(&l->leaf)) {
1613                 if (tp->slen == l->slen)
1614                         node_pull_suffix(tp, tp->pos);
1615                 put_child_root(tp, l->key, NULL);
1616                 node_free(l);
1617                 trie_rebalance(t, tp);
1618                 return;
1619         }
1620 
1621         /* only access fa if it is pointing at the last valid hlist_node */
1622         if (*pprev)
1623                 return;
1624 
1625         /* update the trie with the latest suffix length */
1626         l->slen = fa->fa_slen;
1627         node_pull_suffix(tp, fa->fa_slen);
1628 }
1629 
1630 static void fib_notify_alias_delete(struct net *net, u32 key,
1631                                     struct hlist_head *fah,
1632                                     struct fib_alias *fa_to_delete,
1633                                     struct netlink_ext_ack *extack)
1634 {
1635         struct fib_alias *fa_next, *fa_to_notify;
1636         u32 tb_id = fa_to_delete->tb_id;
1637         u8 slen = fa_to_delete->fa_slen;
1638         enum fib_event_type fib_event;
1639 
1640         /* Do not notify if we do not care about the route. */
1641         if (fib_find_alias(fah, slen, 0, 0, tb_id, true) != fa_to_delete)
1642                 return;
1643 
1644         /* Determine if the route should be replaced by the next route in the
1645          * list.
1646          */
1647         fa_next = hlist_entry_safe(fa_to_delete->fa_list.next,
1648                                    struct fib_alias, fa_list);
1649         if (fa_next && fa_next->fa_slen == slen && fa_next->tb_id == tb_id) {
1650                 fib_event = FIB_EVENT_ENTRY_REPLACE;
1651                 fa_to_notify = fa_next;
1652         } else {
1653                 fib_event = FIB_EVENT_ENTRY_DEL;
1654                 fa_to_notify = fa_to_delete;
1655         }
1656         call_fib_entry_notifiers(net, fib_event, key, KEYLENGTH - slen,
1657                                  fa_to_notify, extack);
1658 }
1659 
1660 /* Caller must hold RTNL. */
1661 int fib_table_delete(struct net *net, struct fib_table *tb,
1662                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1663 {
1664         struct trie *t = (struct trie *) tb->tb_data;
1665         struct fib_alias *fa, *fa_to_delete;
1666         struct key_vector *l, *tp;
1667         u8 plen = cfg->fc_dst_len;
1668         u8 slen = KEYLENGTH - plen;
1669         u8 tos = cfg->fc_tos;
1670         u32 key;
1671 
1672         key = ntohl(cfg->fc_dst);
1673 
1674         if (!fib_valid_key_len(key, plen, extack))
1675                 return -EINVAL;
1676 
1677         l = fib_find_node(t, &tp, key);
1678         if (!l)
1679                 return -ESRCH;
1680 
1681         fa = fib_find_alias(&l->leaf, slen, tos, 0, tb->tb_id, false);
1682         if (!fa)
1683                 return -ESRCH;
1684 
1685         pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
1686 
1687         fa_to_delete = NULL;
1688         hlist_for_each_entry_from(fa, fa_list) {
1689                 struct fib_info *fi = fa->fa_info;
1690 
1691                 if ((fa->fa_slen != slen) ||
1692                     (fa->tb_id != tb->tb_id) ||
1693                     (fa->fa_tos != tos))
1694                         break;
1695 
1696                 if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
1697                     (cfg->fc_scope == RT_SCOPE_NOWHERE ||
1698                      fa->fa_info->fib_scope == cfg->fc_scope) &&
1699                     (!cfg->fc_prefsrc ||
1700                      fi->fib_prefsrc == cfg->fc_prefsrc) &&
1701                     (!cfg->fc_protocol ||
1702                      fi->fib_protocol == cfg->fc_protocol) &&
1703                     fib_nh_match(net, cfg, fi, extack) == 0 &&
1704                     fib_metrics_match(cfg, fi)) {
1705                         fa_to_delete = fa;
1706                         break;
1707                 }
1708         }
1709 
1710         if (!fa_to_delete)
1711                 return -ESRCH;
1712 
1713         fib_notify_alias_delete(net, key, &l->leaf, fa_to_delete, extack);
1714         rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
1715                   &cfg->fc_nlinfo, 0);
1716 
1717         if (!plen)
1718                 tb->tb_num_default--;
1719 
1720         fib_remove_alias(t, tp, l, fa_to_delete);
1721 
1722         if (fa_to_delete->fa_state & FA_S_ACCESSED)
1723                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1724 
1725         fib_release_info(fa_to_delete->fa_info);
1726         alias_free_mem_rcu(fa_to_delete);
1727         return 0;
1728 }
1729 
1730 /* Scan for the next leaf starting at the provided key value */
1731 static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
1732 {
1733         struct key_vector *pn, *n = *tn;
1734         unsigned long cindex;
1735 
1736         /* this loop is meant to try and find the key in the trie */
1737         do {
1738                 /* record parent and next child index */
1739                 pn = n;
1740                 cindex = (key > pn->key) ? get_index(key, pn) : 0;
1741 
1742                 if (cindex >> pn->bits)
1743                         break;
1744 
1745                 /* descend into the next child */
1746                 n = get_child_rcu(pn, cindex++);
1747                 if (!n)
1748                         break;
1749 
1750                 /* guarantee forward progress on the keys */
1751                 if (IS_LEAF(n) && (n->key >= key))
1752                         goto found;
1753         } while (IS_TNODE(n));
1754 
1755         /* this loop will search for the next leaf with a greater key */
1756         while (!IS_TRIE(pn)) {
1757                 /* if we exhausted the parent node we will need to climb */
1758                 if (cindex >= (1ul << pn->bits)) {
1759                         t_key pkey = pn->key;
1760 
1761                         pn = node_parent_rcu(pn);
1762                         cindex = get_index(pkey, pn) + 1;
1763                         continue;
1764                 }
1765 
1766                 /* grab the next available node */
1767                 n = get_child_rcu(pn, cindex++);
1768                 if (!n)
1769                         continue;
1770 
1771                 /* no need to compare keys since we bumped the index */
1772                 if (IS_LEAF(n))
1773                         goto found;
1774 
1775                 /* Rescan start scanning in new node */
1776                 pn = n;
1777                 cindex = 0;
1778         }
1779 
1780         *tn = pn;
1781         return NULL; /* Root of trie */
1782 found:
1783         /* if we are at the limit for keys just return NULL for the tnode */
1784         *tn = pn;
1785         return n;
1786 }
1787 
1788 static void fib_trie_free(struct fib_table *tb)
1789 {
1790         struct trie *t = (struct trie *)tb->tb_data;
1791         struct key_vector *pn = t->kv;
1792         unsigned long cindex = 1;
1793         struct hlist_node *tmp;
1794         struct fib_alias *fa;
1795 
1796         /* walk trie in reverse order and free everything */
1797         for (;;) {
1798                 struct key_vector *n;
1799 
1800                 if (!(cindex--)) {
1801                         t_key pkey = pn->key;
1802 
1803                         if (IS_TRIE(pn))
1804                                 break;
1805 
1806                         n = pn;
1807                         pn = node_parent(pn);
1808 
1809                         /* drop emptied tnode */
1810                         put_child_root(pn, n->key, NULL);
1811                         node_free(n);
1812 
1813                         cindex = get_index(pkey, pn);
1814 
1815                         continue;
1816                 }
1817 
1818                 /* grab the next available node */
1819                 n = get_child(pn, cindex);
1820                 if (!n)
1821                         continue;
1822 
1823                 if (IS_TNODE(n)) {
1824                         /* record pn and cindex for leaf walking */
1825                         pn = n;
1826                         cindex = 1ul << n->bits;
1827 
1828                         continue;
1829                 }
1830 
1831                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1832                         hlist_del_rcu(&fa->fa_list);
1833                         alias_free_mem_rcu(fa);
1834                 }
1835 
1836                 put_child_root(pn, n->key, NULL);
1837                 node_free(n);
1838         }
1839 
1840 #ifdef CONFIG_IP_FIB_TRIE_STATS
1841         free_percpu(t->stats);
1842 #endif
1843         kfree(tb);
1844 }
1845 
1846 struct fib_table *fib_trie_unmerge(struct fib_table *oldtb)
1847 {
1848         struct trie *ot = (struct trie *)oldtb->tb_data;
1849         struct key_vector *l, *tp = ot->kv;
1850         struct fib_table *local_tb;
1851         struct fib_alias *fa;
1852         struct trie *lt;
1853         t_key key = 0;
1854 
1855         if (oldtb->tb_data == oldtb->__data)
1856                 return oldtb;
1857 
1858         local_tb = fib_trie_table(RT_TABLE_LOCAL, NULL);
1859         if (!local_tb)
1860                 return NULL;
1861 
1862         lt = (struct trie *)local_tb->tb_data;
1863 
1864         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1865                 struct key_vector *local_l = NULL, *local_tp;
1866 
1867                 hlist_for_each_entry(fa, &l->leaf, fa_list) {
1868                         struct fib_alias *new_fa;
1869 
1870                         if (local_tb->tb_id != fa->tb_id)
1871                                 continue;
1872 
1873                         /* clone fa for new local table */
1874                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1875                         if (!new_fa)
1876                                 goto out;
1877 
1878                         memcpy(new_fa, fa, sizeof(*fa));
1879 
1880                         /* insert clone into table */
1881                         if (!local_l)
1882                                 local_l = fib_find_node(lt, &local_tp, l->key);
1883 
1884                         if (fib_insert_alias(lt, local_tp, local_l, new_fa,
1885                                              NULL, l->key)) {
1886                                 kmem_cache_free(fn_alias_kmem, new_fa);
1887                                 goto out;
1888                         }
1889                 }
1890 
1891                 /* stop loop if key wrapped back to 0 */
1892                 key = l->key + 1;
1893                 if (key < l->key)
1894                         break;
1895         }
1896 
1897         return local_tb;
1898 out:
1899         fib_trie_free(local_tb);
1900 
1901         return NULL;
1902 }
1903 
1904 /* Caller must hold RTNL */
1905 void fib_table_flush_external(struct fib_table *tb)
1906 {
1907         struct trie *t = (struct trie *)tb->tb_data;
1908         struct key_vector *pn = t->kv;
1909         unsigned long cindex = 1;
1910         struct hlist_node *tmp;
1911         struct fib_alias *fa;
1912 
1913         /* walk trie in reverse order */
1914         for (;;) {
1915                 unsigned char slen = 0;
1916                 struct key_vector *n;
1917 
1918                 if (!(cindex--)) {
1919                         t_key pkey = pn->key;
1920 
1921                         /* cannot resize the trie vector */
1922                         if (IS_TRIE(pn))
1923                                 break;
1924 
1925                         /* update the suffix to address pulled leaves */
1926                         if (pn->slen > pn->pos)
1927                                 update_suffix(pn);
1928 
1929                         /* resize completed node */
1930                         pn = resize(t, pn);
1931                         cindex = get_index(pkey, pn);
1932 
1933                         continue;
1934                 }
1935 
1936                 /* grab the next available node */
1937                 n = get_child(pn, cindex);
1938                 if (!n)
1939                         continue;
1940 
1941                 if (IS_TNODE(n)) {
1942                         /* record pn and cindex for leaf walking */
1943                         pn = n;
1944                         cindex = 1ul << n->bits;
1945 
1946                         continue;
1947                 }
1948 
1949                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1950                         /* if alias was cloned to local then we just
1951                          * need to remove the local copy from main
1952                          */
1953                         if (tb->tb_id != fa->tb_id) {
1954                                 hlist_del_rcu(&fa->fa_list);
1955                                 alias_free_mem_rcu(fa);
1956                                 continue;
1957                         }
1958 
1959                         /* record local slen */
1960                         slen = fa->fa_slen;
1961                 }
1962 
1963                 /* update leaf slen */
1964                 n->slen = slen;
1965 
1966                 if (hlist_empty(&n->leaf)) {
1967                         put_child_root(pn, n->key, NULL);
1968                         node_free(n);
1969                 }
1970         }
1971 }
1972 
1973 /* Caller must hold RTNL. */
1974 int fib_table_flush(struct net *net, struct fib_table *tb, bool flush_all)
1975 {
1976         struct trie *t = (struct trie *)tb->tb_data;
1977         struct key_vector *pn = t->kv;
1978         unsigned long cindex = 1;
1979         struct hlist_node *tmp;
1980         struct fib_alias *fa;
1981         int found = 0;
1982 
1983         /* walk trie in reverse order */
1984         for (;;) {
1985                 unsigned char slen = 0;
1986                 struct key_vector *n;
1987 
1988                 if (!(cindex--)) {
1989                         t_key pkey = pn->key;
1990 
1991                         /* cannot resize the trie vector */
1992                         if (IS_TRIE(pn))
1993                                 break;
1994 
1995                         /* update the suffix to address pulled leaves */
1996                         if (pn->slen > pn->pos)
1997                                 update_suffix(pn);
1998 
1999                         /* resize completed node */
2000                         pn = resize(t, pn);
2001                         cindex = get_index(pkey, pn);
2002 
2003                         continue;
2004                 }
2005 
2006                 /* grab the next available node */
2007                 n = get_child(pn, cindex);
2008                 if (!n)
2009                         continue;
2010 
2011                 if (IS_TNODE(n)) {
2012                         /* record pn and cindex for leaf walking */
2013                         pn = n;
2014                         cindex = 1ul << n->bits;
2015 
2016                         continue;
2017                 }
2018 
2019                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
2020                         struct fib_info *fi = fa->fa_info;
2021 
2022                         if (!fi || tb->tb_id != fa->tb_id ||
2023                             (!(fi->fib_flags & RTNH_F_DEAD) &&
2024                              !fib_props[fa->fa_type].error)) {
2025                                 slen = fa->fa_slen;
2026                                 continue;
2027                         }
2028 
2029                         /* Do not flush error routes if network namespace is
2030                          * not being dismantled
2031                          */
2032                         if (!flush_all && fib_props[fa->fa_type].error) {
2033                                 slen = fa->fa_slen;
2034                                 continue;
2035                         }
2036 
2037                         fib_notify_alias_delete(net, n->key, &n->leaf, fa,
2038                                                 NULL);
2039                         hlist_del_rcu(&fa->fa_list);
2040                         fib_release_info(fa->fa_info);
2041                         alias_free_mem_rcu(fa);
2042                         found++;
2043                 }
2044 
2045                 /* update leaf slen */
2046                 n->slen = slen;
2047 
2048                 if (hlist_empty(&n->leaf)) {
2049                         put_child_root(pn, n->key, NULL);
2050                         node_free(n);
2051                 }
2052         }
2053 
2054         pr_debug("trie_flush found=%d\n", found);
2055         return found;
2056 }
2057 
2058 /* derived from fib_trie_free */
2059 static void __fib_info_notify_update(struct net *net, struct fib_table *tb,
2060                                      struct nl_info *info)
2061 {
2062         struct trie *t = (struct trie *)tb->tb_data;
2063         struct key_vector *pn = t->kv;
2064         unsigned long cindex = 1;
2065         struct fib_alias *fa;
2066 
2067         for (;;) {
2068                 struct key_vector *n;
2069 
2070                 if (!(cindex--)) {
2071                         t_key pkey = pn->key;
2072 
2073                         if (IS_TRIE(pn))
2074                                 break;
2075 
2076                         pn = node_parent(pn);
2077                         cindex = get_index(pkey, pn);
2078                         continue;
2079                 }
2080 
2081                 /* grab the next available node */
2082                 n = get_child(pn, cindex);
2083                 if (!n)
2084                         continue;
2085 
2086                 if (IS_TNODE(n)) {
2087                         /* record pn and cindex for leaf walking */
2088                         pn = n;
2089                         cindex = 1ul << n->bits;
2090 
2091                         continue;
2092                 }
2093 
2094                 hlist_for_each_entry(fa, &n->leaf, fa_list) {
2095                         struct fib_info *fi = fa->fa_info;
2096 
2097                         if (!fi || !fi->nh_updated || fa->tb_id != tb->tb_id)
2098                                 continue;
2099 
2100                         rtmsg_fib(RTM_NEWROUTE, htonl(n->key), fa,
2101                                   KEYLENGTH - fa->fa_slen, tb->tb_id,
2102                                   info, NLM_F_REPLACE);
2103 
2104                         /* call_fib_entry_notifiers will be removed when
2105                          * in-kernel notifier is implemented and supported
2106                          * for nexthop objects
2107                          */
2108                         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_REPLACE,
2109                                                  n->key,
2110                                                  KEYLENGTH - fa->fa_slen, fa,
2111                                                  NULL);
2112                 }
2113         }
2114 }
2115 
2116 void fib_info_notify_update(struct net *net, struct nl_info *info)
2117 {
2118         unsigned int h;
2119 
2120         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2121                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2122                 struct fib_table *tb;
2123 
2124                 hlist_for_each_entry_rcu(tb, head, tb_hlist)
2125                         __fib_info_notify_update(net, tb, info);
2126         }
2127 }
2128 
2129 static int fib_leaf_notify(struct key_vector *l, struct fib_table *tb,
2130                            struct notifier_block *nb,
2131                            struct netlink_ext_ack *extack)
2132 {
2133         struct fib_alias *fa;
2134         int last_slen = -1;
2135         int err;
2136 
2137         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2138                 struct fib_info *fi = fa->fa_info;
2139 
2140                 if (!fi)
2141                         continue;
2142 
2143                 /* local and main table can share the same trie,
2144                  * so don't notify twice for the same entry.
2145                  */
2146                 if (tb->tb_id != fa->tb_id)
2147                         continue;
2148 
2149                 if (fa->fa_slen == last_slen)
2150                         continue;
2151 
2152                 last_slen = fa->fa_slen;
2153                 err = call_fib_entry_notifier(nb, FIB_EVENT_ENTRY_REPLACE,
2154                                               l->key, KEYLENGTH - fa->fa_slen,
2155                                               fa, extack);
2156                 if (err)
2157                         return err;
2158         }
2159         return 0;
2160 }
2161 
2162 static int fib_table_notify(struct fib_table *tb, struct notifier_block *nb,
2163                             struct netlink_ext_ack *extack)
2164 {
2165         struct trie *t = (struct trie *)tb->tb_data;
2166         struct key_vector *l, *tp = t->kv;
2167         t_key key = 0;
2168         int err;
2169 
2170         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
2171                 err = fib_leaf_notify(l, tb, nb, extack);
2172                 if (err)
2173                         return err;
2174 
2175                 key = l->key + 1;
2176                 /* stop in case of wrap around */
2177                 if (key < l->key)
2178                         break;
2179         }
2180         return 0;
2181 }
2182 
2183 int fib_notify(struct net *net, struct notifier_block *nb,
2184                struct netlink_ext_ack *extack)
2185 {
2186         unsigned int h;
2187         int err;
2188 
2189         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2190                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2191                 struct fib_table *tb;
2192 
2193                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2194                         err = fib_table_notify(tb, nb, extack);
2195                         if (err)
2196                                 return err;
2197                 }
2198         }
2199         return 0;
2200 }
2201 
2202 static void __trie_free_rcu(struct rcu_head *head)
2203 {
2204         struct fib_table *tb = container_of(head, struct fib_table, rcu);
2205 #ifdef CONFIG_IP_FIB_TRIE_STATS
2206         struct trie *t = (struct trie *)tb->tb_data;
2207 
2208         if (tb->tb_data == tb->__data)
2209                 free_percpu(t->stats);
2210 #endif /* CONFIG_IP_FIB_TRIE_STATS */
2211         kfree(tb);
2212 }
2213 
2214 void fib_free_table(struct fib_table *tb)
2215 {
2216         call_rcu(&tb->rcu, __trie_free_rcu);
2217 }
2218 
2219 static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
2220                              struct sk_buff *skb, struct netlink_callback *cb,
2221                              struct fib_dump_filter *filter)
2222 {
2223         unsigned int flags = NLM_F_MULTI;
2224         __be32 xkey = htonl(l->key);
2225         int i, s_i, i_fa, s_fa, err;
2226         struct fib_alias *fa;
2227 
2228         if (filter->filter_set ||
2229             !filter->dump_exceptions || !filter->dump_routes)
2230                 flags |= NLM_F_DUMP_FILTERED;
2231 
2232         s_i = cb->args[4];
2233         s_fa = cb->args[5];
2234         i = 0;
2235 
2236         /* rcu_read_lock is hold by caller */
2237         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2238                 struct fib_info *fi = fa->fa_info;
2239 
2240                 if (i < s_i)
2241                         goto next;
2242 
2243                 i_fa = 0;
2244 
2245                 if (tb->tb_id != fa->tb_id)
2246                         goto next;
2247 
2248                 if (filter->filter_set) {
2249                         if (filter->rt_type && fa->fa_type != filter->rt_type)
2250                                 goto next;
2251 
2252                         if ((filter->protocol &&
2253                              fi->fib_protocol != filter->protocol))
2254                                 goto next;
2255 
2256                         if (filter->dev &&
2257                             !fib_info_nh_uses_dev(fi, filter->dev))
2258                                 goto next;
2259                 }
2260 
2261                 if (filter->dump_routes) {
2262                         if (!s_fa) {
2263                                 struct fib_rt_info fri;
2264 
2265                                 fri.fi = fi;
2266                                 fri.tb_id = tb->tb_id;
2267                                 fri.dst = xkey;
2268                                 fri.dst_len = KEYLENGTH - fa->fa_slen;
2269                                 fri.tos = fa->fa_tos;
2270                                 fri.type = fa->fa_type;
2271                                 fri.offload = fa->offload;
2272                                 fri.trap = fa->trap;
2273                                 err = fib_dump_info(skb,
2274                                                     NETLINK_CB(cb->skb).portid,
2275                                                     cb->nlh->nlmsg_seq,
2276                                                     RTM_NEWROUTE, &fri, flags);
2277                                 if (err < 0)
2278                                         goto stop;
2279                         }
2280 
2281                         i_fa++;
2282                 }
2283 
2284                 if (filter->dump_exceptions) {
2285                         err = fib_dump_info_fnhe(skb, cb, tb->tb_id, fi,
2286                                                  &i_fa, s_fa, flags);
2287                         if (err < 0)
2288                                 goto stop;
2289                 }
2290 
2291 next:
2292                 i++;
2293         }
2294 
2295         cb->args[4] = i;
2296         return skb->len;
2297 
2298 stop:
2299         cb->args[4] = i;
2300         cb->args[5] = i_fa;
2301         return err;
2302 }
2303 
2304 /* rcu_read_lock needs to be hold by caller from readside */
2305 int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
2306                    struct netlink_callback *cb, struct fib_dump_filter *filter)
2307 {
2308         struct trie *t = (struct trie *)tb->tb_data;
2309         struct key_vector *l, *tp = t->kv;
2310         /* Dump starting at last key.
2311          * Note: 0.0.0.0/0 (ie default) is first key.
2312          */
2313         int count = cb->args[2];
2314         t_key key = cb->args[3];
2315 
2316         /* First time here, count and key are both always 0. Count > 0
2317          * and key == 0 means the dump has wrapped around and we are done.
2318          */
2319         if (count && !key)
2320                 return skb->len;
2321 
2322         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
2323                 int err;
2324 
2325                 err = fn_trie_dump_leaf(l, tb, skb, cb, filter);
2326                 if (err < 0) {
2327                         cb->args[3] = key;
2328                         cb->args[2] = count;
2329                         return err;
2330                 }
2331 
2332                 ++count;
2333                 key = l->key + 1;
2334 
2335                 memset(&cb->args[4], 0,
2336                        sizeof(cb->args) - 4*sizeof(cb->args[0]));
2337 
2338                 /* stop loop if key wrapped back to 0 */
2339                 if (key < l->key)
2340                         break;
2341         }
2342 
2343         cb->args[3] = key;
2344         cb->args[2] = count;
2345 
2346         return skb->len;
2347 }
2348 
2349 void __init fib_trie_init(void)
2350 {
2351         fn_alias_kmem = kmem_cache_create("ip_fib_alias",
2352                                           sizeof(struct fib_alias),
2353                                           0, SLAB_PANIC, NULL);
2354 
2355         trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
2356                                            LEAF_SIZE,
2357                                            0, SLAB_PANIC, NULL);
2358 }
2359 
2360 struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
2361 {
2362         struct fib_table *tb;
2363         struct trie *t;
2364         size_t sz = sizeof(*tb);
2365 
2366         if (!alias)
2367                 sz += sizeof(struct trie);
2368 
2369         tb = kzalloc(sz, GFP_KERNEL);
2370         if (!tb)
2371                 return NULL;
2372 
2373         tb->tb_id = id;
2374         tb->tb_num_default = 0;
2375         tb->tb_data = (alias ? alias->__data : tb->__data);
2376 
2377         if (alias)
2378                 return tb;
2379 
2380         t = (struct trie *) tb->tb_data;
2381         t->kv[0].pos = KEYLENGTH;
2382         t->kv[0].slen = KEYLENGTH;
2383 #ifdef CONFIG_IP_FIB_TRIE_STATS
2384         t->stats = alloc_percpu(struct trie_use_stats);
2385         if (!t->stats) {
2386                 kfree(tb);
2387                 tb = NULL;
2388         }
2389 #endif
2390 
2391         return tb;
2392 }
2393 
2394 #ifdef CONFIG_PROC_FS
2395 /* Depth first Trie walk iterator */
2396 struct fib_trie_iter {
2397         struct seq_net_private p;
2398         struct fib_table *tb;
2399         struct key_vector *tnode;
2400         unsigned int index;
2401         unsigned int depth;
2402 };
2403 
2404 static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
2405 {
2406         unsigned long cindex = iter->index;
2407         struct key_vector *pn = iter->tnode;
2408         t_key pkey;
2409 
2410         pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
2411                  iter->tnode, iter->index, iter->depth);
2412 
2413         while (!IS_TRIE(pn)) {
2414                 while (cindex < child_length(pn)) {
2415                         struct key_vector *n = get_child_rcu(pn, cindex++);
2416 
2417                         if (!n)
2418                                 continue;
2419 
2420                         if (IS_LEAF(n)) {
2421                                 iter->tnode = pn;
2422                                 iter->index = cindex;
2423                         } else {
2424                                 /* push down one level */
2425                                 iter->tnode = n;
2426                                 iter->index = 0;
2427                                 ++iter->depth;
2428                         }
2429 
2430                         return n;
2431                 }
2432 
2433                 /* Current node exhausted, pop back up */
2434                 pkey = pn->key;
2435                 pn = node_parent_rcu(pn);
2436                 cindex = get_index(pkey, pn) + 1;
2437                 --iter->depth;
2438         }
2439 
2440         /* record root node so further searches know we are done */
2441         iter->tnode = pn;
2442         iter->index = 0;
2443 
2444         return NULL;
2445 }
2446 
2447 static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
2448                                              struct trie *t)
2449 {
2450         struct key_vector *n, *pn;
2451 
2452         if (!t)
2453                 return NULL;
2454 
2455         pn = t->kv;
2456         n = rcu_dereference(pn->tnode[0]);
2457         if (!n)
2458                 return NULL;
2459 
2460         if (IS_TNODE(n)) {
2461                 iter->tnode = n;
2462                 iter->index = 0;
2463                 iter->depth = 1;
2464         } else {
2465                 iter->tnode = pn;
2466                 iter->index = 0;
2467                 iter->depth = 0;
2468         }
2469 
2470         return n;
2471 }
2472 
2473 static void trie_collect_stats(struct trie *t, struct trie_stat *s)
2474 {
2475         struct key_vector *n;
2476         struct fib_trie_iter iter;
2477 
2478         memset(s, 0, sizeof(*s));
2479 
2480         rcu_read_lock();
2481         for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
2482                 if (IS_LEAF(n)) {
2483                         struct fib_alias *fa;
2484 
2485                         s->leaves++;
2486                         s->totdepth += iter.depth;
2487                         if (iter.depth > s->maxdepth)
2488                                 s->maxdepth = iter.depth;
2489 
2490                         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list)
2491                                 ++s->prefixes;
2492                 } else {
2493                         s->tnodes++;
2494                         if (n->bits < MAX_STAT_DEPTH)
2495                                 s->nodesizes[n->bits]++;
2496                         s->nullpointers += tn_info(n)->empty_children;
2497                 }
2498         }
2499         rcu_read_unlock();
2500 }
2501 
2502 /*
2503  *      This outputs /proc/net/fib_triestats
2504  */
2505 static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
2506 {
2507         unsigned int i, max, pointers, bytes, avdepth;
2508 
2509         if (stat->leaves)
2510                 avdepth = stat->totdepth*100 / stat->leaves;
2511         else
2512                 avdepth = 0;
2513 
2514         seq_printf(seq, "\tAver depth:     %u.%02d\n",
2515                    avdepth / 100, avdepth % 100);
2516         seq_printf(seq, "\tMax depth:      %u\n", stat->maxdepth);
2517 
2518         seq_printf(seq, "\tLeaves:         %u\n", stat->leaves);
2519         bytes = LEAF_SIZE * stat->leaves;
2520 
2521         seq_printf(seq, "\tPrefixes:       %u\n", stat->prefixes);
2522         bytes += sizeof(struct fib_alias) * stat->prefixes;
2523 
2524         seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
2525         bytes += TNODE_SIZE(0) * stat->tnodes;
2526 
2527         max = MAX_STAT_DEPTH;
2528         while (max > 0 && stat->nodesizes[max-1] == 0)
2529                 max--;
2530 
2531         pointers = 0;
2532         for (i = 1; i < max; i++)
2533                 if (stat->nodesizes[i] != 0) {
2534                         seq_printf(seq, "  %u: %u",  i, stat->nodesizes[i]);
2535                         pointers += (1<<i) * stat->nodesizes[i];
2536                 }
2537         seq_putc(seq, '\n');
2538         seq_printf(seq, "\tPointers: %u\n", pointers);
2539 
2540         bytes += sizeof(struct key_vector *) * pointers;
2541         seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
2542         seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
2543 }
2544 
2545 #ifdef CONFIG_IP_FIB_TRIE_STATS
2546 static void trie_show_usage(struct seq_file *seq,
2547                             const struct trie_use_stats __percpu *stats)
2548 {
2549         struct trie_use_stats s = { 0 };
2550         int cpu;
2551 
2552         /* loop through all of the CPUs and gather up the stats */
2553         for_each_possible_cpu(cpu) {
2554                 const struct trie_use_stats *pcpu = per_cpu_ptr(stats, cpu);
2555 
2556                 s.gets += pcpu->gets;
2557                 s.backtrack += pcpu->backtrack;
2558                 s.semantic_match_passed += pcpu->semantic_match_passed;
2559                 s.semantic_match_miss += pcpu->semantic_match_miss;
2560                 s.null_node_hit += pcpu->null_node_hit;
2561                 s.resize_node_skipped += pcpu->resize_node_skipped;
2562         }
2563 
2564         seq_printf(seq, "\nCounters:\n---------\n");
2565         seq_printf(seq, "gets = %u\n", s.gets);
2566         seq_printf(seq, "backtracks = %u\n", s.backtrack);
2567         seq_printf(seq, "semantic match passed = %u\n",
2568                    s.semantic_match_passed);
2569         seq_printf(seq, "semantic match miss = %u\n", s.semantic_match_miss);
2570         seq_printf(seq, "null node hit= %u\n", s.null_node_hit);
2571         seq_printf(seq, "skipped node resize = %u\n\n", s.resize_node_skipped);
2572 }
2573 #endif /*  CONFIG_IP_FIB_TRIE_STATS */
2574 
2575 static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
2576 {
2577         if (tb->tb_id == RT_TABLE_LOCAL)
2578                 seq_puts(seq, "Local:\n");
2579         else if (tb->tb_id == RT_TABLE_MAIN)
2580                 seq_puts(seq, "Main:\n");
2581         else
2582                 seq_printf(seq, "Id %d:\n", tb->tb_id);
2583 }
2584 
2585 
2586 static int fib_triestat_seq_show(struct seq_file *seq, void *v)
2587 {
2588         struct net *net = (struct net *)seq->private;
2589         unsigned int h;
2590 
2591         seq_printf(seq,
2592                    "Basic info: size of leaf:"
2593                    " %zd bytes, size of tnode: %zd bytes.\n",
2594                    LEAF_SIZE, TNODE_SIZE(0));
2595 
2596         rcu_read_lock();
2597         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2598                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2599                 struct fib_table *tb;
2600 
2601                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2602                         struct trie *t = (struct trie *) tb->tb_data;
2603                         struct trie_stat stat;
2604 
2605                         if (!t)
2606                                 continue;
2607 
2608                         fib_table_print(seq, tb);
2609 
2610                         trie_collect_stats(t, &stat);
2611                         trie_show_stats(seq, &stat);
2612 #ifdef CONFIG_IP_FIB_TRIE_STATS
2613                         trie_show_usage(seq, t->stats);
2614 #endif
2615                 }
2616                 cond_resched_rcu();
2617         }
2618         rcu_read_unlock();
2619 
2620         return 0;
2621 }
2622 
2623 static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
2624 {
2625         struct fib_trie_iter *iter = seq->private;
2626         struct net *net = seq_file_net(seq);
2627         loff_t idx = 0;
2628         unsigned int h;
2629 
2630         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2631                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2632                 struct fib_table *tb;
2633 
2634                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2635                         struct key_vector *n;
2636 
2637                         for (n = fib_trie_get_first(iter,
2638                                                     (struct trie *) tb->tb_data);
2639                              n; n = fib_trie_get_next(iter))
2640                                 if (pos == idx++) {
2641                                         iter->tb = tb;
2642                                         return n;
2643                                 }
2644                 }
2645         }
2646 
2647         return NULL;
2648 }
2649 
2650 static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
2651         __acquires(RCU)
2652 {
2653         rcu_read_lock();
2654         return fib_trie_get_idx(seq, *pos);
2655 }
2656 
2657 static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2658 {
2659         struct fib_trie_iter *iter = seq->private;
2660         struct net *net = seq_file_net(seq);
2661         struct fib_table *tb = iter->tb;
2662         struct hlist_node *tb_node;
2663         unsigned int h;
2664         struct key_vector *n;
2665 
2666         ++*pos;
2667         /* next node in same table */
2668         n = fib_trie_get_next(iter);
2669         if (n)
2670                 return n;
2671 
2672         /* walk rest of this hash chain */
2673         h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
2674         while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
2675                 tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
2676                 n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2677                 if (n)
2678                         goto found;
2679         }
2680 
2681         /* new hash chain */
2682         while (++h < FIB_TABLE_HASHSZ) {
2683                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2684                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2685                         n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2686                         if (n)
2687                                 goto found;
2688                 }
2689         }
2690         return NULL;
2691 
2692 found:
2693         iter->tb = tb;
2694         return n;
2695 }
2696 
2697 static void fib_trie_seq_stop(struct seq_file *seq, void *v)
2698         __releases(RCU)
2699 {
2700         rcu_read_unlock();
2701 }
2702 
2703 static void seq_indent(struct seq_file *seq, int n)
2704 {
2705         while (n-- > 0)
2706                 seq_puts(seq, "   ");
2707 }
2708 
2709 static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
2710 {
2711         switch (s) {
2712         case RT_SCOPE_UNIVERSE: return "universe";
2713         case RT_SCOPE_SITE:     return "site";
2714         case RT_SCOPE_LINK:     return "link";
2715         case RT_SCOPE_HOST:     return "host";
2716         case RT_SCOPE_NOWHERE:  return "nowhere";
2717         default:
2718                 snprintf(buf, len, "scope=%d", s);
2719                 return buf;
2720         }
2721 }
2722 
2723 static const char *const rtn_type_names[__RTN_MAX] = {
2724         [RTN_UNSPEC] = "UNSPEC",
2725         [RTN_UNICAST] = "UNICAST",
2726         [RTN_LOCAL] = "LOCAL",
2727         [RTN_BROADCAST] = "BROADCAST",
2728         [RTN_ANYCAST] = "ANYCAST",
2729         [RTN_MULTICAST] = "MULTICAST",
2730         [RTN_BLACKHOLE] = "BLACKHOLE",
2731         [RTN_UNREACHABLE] = "UNREACHABLE",
2732         [RTN_PROHIBIT] = "PROHIBIT",
2733         [RTN_THROW] = "THROW",
2734         [RTN_NAT] = "NAT",
2735         [RTN_XRESOLVE] = "XRESOLVE",
2736 };
2737 
2738 static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
2739 {
2740         if (t < __RTN_MAX && rtn_type_names[t])
2741                 return rtn_type_names[t];
2742         snprintf(buf, len, "type %u", t);
2743         return buf;
2744 }
2745 
2746 /* Pretty print the trie */
2747 static int fib_trie_seq_show(struct seq_file *seq, void *v)
2748 {
2749         const struct fib_trie_iter *iter = seq->private;
2750         struct key_vector *n = v;
2751 
2752         if (IS_TRIE(node_parent_rcu(n)))
2753                 fib_table_print(seq, iter->tb);
2754 
2755         if (IS_TNODE(n)) {
2756                 __be32 prf = htonl(n->key);
2757 
2758                 seq_indent(seq, iter->depth-1);
2759                 seq_printf(seq, "  +-- %pI4/%zu %u %u %u\n",
2760                            &prf, KEYLENGTH - n->pos - n->bits, n->bits,
2761                            tn_info(n)->full_children,
2762                            tn_info(n)->empty_children);
2763         } else {
2764                 __be32 val = htonl(n->key);
2765                 struct fib_alias *fa;
2766 
2767                 seq_indent(seq, iter->depth);
2768                 seq_printf(seq, "  |-- %pI4\n", &val);
2769 
2770                 hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
2771                         char buf1[32], buf2[32];
2772 
2773                         seq_indent(seq, iter->depth + 1);
2774                         seq_printf(seq, "  /%zu %s %s",
2775                                    KEYLENGTH - fa->fa_slen,
2776                                    rtn_scope(buf1, sizeof(buf1),
2777                                              fa->fa_info->fib_scope),
2778                                    rtn_type(buf2, sizeof(buf2),
2779                                             fa->fa_type));
2780                         if (fa->fa_tos)
2781                                 seq_printf(seq, " tos=%d", fa->fa_tos);
2782                         seq_putc(seq, '\n');
2783                 }
2784         }
2785 
2786         return 0;
2787 }
2788 
2789 static const struct seq_operations fib_trie_seq_ops = {
2790         .start  = fib_trie_seq_start,
2791         .next   = fib_trie_seq_next,
2792         .stop   = fib_trie_seq_stop,
2793         .show   = fib_trie_seq_show,
2794 };
2795 
2796 struct fib_route_iter {
2797         struct seq_net_private p;
2798         struct fib_table *main_tb;
2799         struct key_vector *tnode;
2800         loff_t  pos;
2801         t_key   key;
2802 };
2803 
2804 static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
2805                                             loff_t pos)
2806 {
2807         struct key_vector *l, **tp = &iter->tnode;
2808         t_key key;
2809 
2810         /* use cached location of previously found key */
2811         if (iter->pos > 0 && pos >= iter->pos) {
2812                 key = iter->key;
2813         } else {
2814                 iter->pos = 1;
2815                 key = 0;
2816         }
2817 
2818         pos -= iter->pos;
2819 
2820         while ((l = leaf_walk_rcu(tp, key)) && (pos-- > 0)) {
2821                 key = l->key + 1;
2822                 iter->pos++;
2823                 l = NULL;
2824 
2825                 /* handle unlikely case of a key wrap */
2826                 if (!key)
2827                         break;
2828         }
2829 
2830         if (l)
2831                 iter->key = l->key;     /* remember it */
2832         else
2833                 iter->pos = 0;          /* forget it */
2834 
2835         return l;
2836 }
2837 
2838 static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
2839         __acquires(RCU)
2840 {
2841         struct fib_route_iter *iter = seq->private;
2842         struct fib_table *tb;
2843         struct trie *t;
2844 
2845         rcu_read_lock();
2846 
2847         tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
2848         if (!tb)
2849                 return NULL;
2850 
2851         iter->main_tb = tb;
2852         t = (struct trie *)tb->tb_data;
2853         iter->tnode = t->kv;
2854 
2855         if (*pos != 0)
2856                 return fib_route_get_idx(iter, *pos);
2857 
2858         iter->pos = 0;
2859         iter->key = KEY_MAX;
2860 
2861         return SEQ_START_TOKEN;
2862 }
2863 
2864 static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2865 {
2866         struct fib_route_iter *iter = seq->private;
2867         struct key_vector *l = NULL;
2868         t_key key = iter->key + 1;
2869 
2870         ++*pos;
2871 
2872         /* only allow key of 0 for start of sequence */
2873         if ((v == SEQ_START_TOKEN) || key)
2874                 l = leaf_walk_rcu(&iter->tnode, key);
2875 
2876         if (l) {
2877                 iter->key = l->key;
2878                 iter->pos++;
2879         } else {
2880                 iter->pos = 0;
2881         }
2882 
2883         return l;
2884 }
2885 
2886 static void fib_route_seq_stop(struct seq_file *seq, void *v)
2887         __releases(RCU)
2888 {
2889         rcu_read_unlock();
2890 }
2891 
2892 static unsigned int fib_flag_trans(int type, __be32 mask, struct fib_info *fi)
2893 {
2894         unsigned int flags = 0;
2895 
2896         if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
2897                 flags = RTF_REJECT;
2898         if (fi) {
2899                 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
2900 
2901                 if (nhc->nhc_gw.ipv4)
2902                         flags |= RTF_GATEWAY;
2903         }
2904         if (mask == htonl(0xFFFFFFFF))
2905                 flags |= RTF_HOST;
2906         flags |= RTF_UP;
2907         return flags;
2908 }
2909 
2910 /*
2911  *      This outputs /proc/net/route.
2912  *      The format of the file is not supposed to be changed
2913  *      and needs to be same as fib_hash output to avoid breaking
2914  *      legacy utilities
2915  */
2916 static int fib_route_seq_show(struct seq_file *seq, void *v)
2917 {
2918         struct fib_route_iter *iter = seq->private;
2919         struct fib_table *tb = iter->main_tb;
2920         struct fib_alias *fa;
2921         struct key_vector *l = v;
2922         __be32 prefix;
2923 
2924         if (v == SEQ_START_TOKEN) {
2925                 seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
2926                            "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
2927                            "\tWindow\tIRTT");
2928                 return 0;
2929         }
2930 
2931         prefix = htonl(l->key);
2932 
2933         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2934                 struct fib_info *fi = fa->fa_info;
2935                 __be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
2936                 unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
2937 
2938                 if ((fa->fa_type == RTN_BROADCAST) ||
2939                     (fa->fa_type == RTN_MULTICAST))
2940                         continue;
2941 
2942                 if (fa->tb_id != tb->tb_id)
2943                         continue;
2944 
2945                 seq_setwidth(seq, 127);
2946 
2947                 if (fi) {
2948                         struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
2949                         __be32 gw = 0;
2950 
2951                         if (nhc->nhc_gw_family == AF_INET)
2952                                 gw = nhc->nhc_gw.ipv4;
2953 
2954                         seq_printf(seq,
2955                                    "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
2956                                    "%d\t%08X\t%d\t%u\t%u",
2957                                    nhc->nhc_dev ? nhc->nhc_dev->name : "*",
2958                                    prefix, gw, flags, 0, 0,
2959                                    fi->fib_priority,
2960                                    mask,
2961                                    (fi->fib_advmss ?
2962                                     fi->fib_advmss + 40 : 0),
2963                                    fi->fib_window,
2964                                    fi->fib_rtt >> 3);
2965                 } else {
2966                         seq_printf(seq,
2967                                    "*\t%08X\t%08X\t%04X\t%d\t%u\t"
2968                                    "%d\t%08X\t%d\t%u\t%u",
2969                                    prefix, 0, flags, 0, 0, 0,
2970                                    mask, 0, 0, 0);
2971                 }
2972                 seq_pad(seq, '\n');
2973         }
2974 
2975         return 0;
2976 }
2977 
2978 static const struct seq_operations fib_route_seq_ops = {
2979         .start  = fib_route_seq_start,
2980         .next   = fib_route_seq_next,
2981         .stop   = fib_route_seq_stop,
2982         .show   = fib_route_seq_show,
2983 };
2984 
2985 int __net_init fib_proc_init(struct net *net)
2986 {
2987         if (!proc_create_net("fib_trie", 0444, net->proc_net, &fib_trie_seq_ops,
2988                         sizeof(struct fib_trie_iter)))
2989                 goto out1;
2990 
2991         if (!proc_create_net_single("fib_triestat", 0444, net->proc_net,
2992                         fib_triestat_seq_show, NULL))
2993                 goto out2;
2994 
2995         if (!proc_create_net("route", 0444, net->proc_net, &fib_route_seq_ops,
2996                         sizeof(struct fib_route_iter)))
2997                 goto out3;
2998 
2999         return 0;
3000 
3001 out3:
3002         remove_proc_entry("fib_triestat", net->proc_net);
3003 out2:
3004         remove_proc_entry("fib_trie", net->proc_net);
3005 out1:
3006         return -ENOMEM;
3007 }
3008 
3009 void __net_exit fib_proc_exit(struct net *net)
3010 {
3011         remove_proc_entry("fib_trie", net->proc_net);
3012         remove_proc_entry("fib_triestat", net->proc_net);
3013         remove_proc_entry("route", net->proc_net);
3014 }
3015 
3016 #endif /* CONFIG_PROC_FS */
3017 

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