root/net/ipv4/fib_trie.c

DEFINITIONS

1. call_fib_entry_notifier
2. call_fib_entry_notifiers
3. tn_info
4. node_set_parent
5. child_length
6. get_index
7. __alias_free_mem
8. alias_free_mem_rcu
9. tnode_alloc
10. empty_child_inc
11. empty_child_dec
12. leaf_new
13. tnode_new
14. tnode_full
15. put_child
16. update_children
17. put_child_root
18. tnode_free_init
19. tnode_free_append
20. tnode_free
21. replace
22. inflate
23. halve
24. collapse
25. update_suffix
26. should_inflate
27. should_halve
28. should_collapse
29. resize
30. node_pull_suffix
31. node_push_suffix
32. fib_find_node
33. fib_find_alias
34. trie_rebalance
35. fib_insert_node
36. fib_insert_alias
37. fib_valid_key_len
38. fib_table_insert
39. prefix_mismatch
40. fib_table_lookup
41. fib_remove_alias
42. fib_table_delete
43. leaf_walk_rcu
44. fib_trie_free
45. fib_trie_unmerge
46. fib_table_flush_external
47. fib_table_flush
48. __fib_info_notify_update
49. fib_info_notify_update
50. fib_leaf_notify
51. fib_table_notify
52. fib_notify
53. __trie_free_rcu
54. fib_free_table
55. fn_trie_dump_leaf
56. fib_table_dump
57. fib_trie_init
58. fib_trie_table
59. fib_trie_get_next
60. fib_trie_get_first
61. trie_collect_stats
62. trie_show_stats
63. trie_show_usage
64. fib_table_print
65. fib_triestat_seq_show
66. fib_trie_get_idx
67. fib_trie_seq_start
68. fib_trie_seq_next
69. fib_trie_seq_stop
70. seq_indent
71. rtn_scope
72. rtn_type
73. fib_trie_seq_show
74. fib_route_get_idx
75. fib_route_seq_start
76. fib_route_seq_next
77. fib_route_seq_stop
78. fib_flag_trans
79. fib_route_seq_show
80. fib_proc_init
81. fib_proc_exit

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *
   4  *   Robert Olsson <robert.olsson@its.uu.se> Uppsala Universitet
   5  *     & Swedish University of Agricultural Sciences.
   6  *
   7  *   Jens Laas <jens.laas@data.slu.se> Swedish University of
   8  *     Agricultural Sciences.
   9  *
  10  *   Hans Liss <hans.liss@its.uu.se>  Uppsala Universitet
  11  *
  12  * This work is based on the LPC-trie which is originally described in:
  13  *
  14  * An experimental study of compression methods for dynamic tries
  15  * Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
  16  * http://www.csc.kth.se/~snilsson/software/dyntrie2/
  17  *
  18  * IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
  19  * IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
  20  *
  21  * Code from fib_hash has been reused which includes the following header:
  22  *
  23  * INET         An implementation of the TCP/IP protocol suite for the LINUX
  24  *              operating system.  INET is implemented using the  BSD Socket
  25  *              interface as the means of communication with the user level.
  26  *
  27  *              IPv4 FIB: lookup engine and maintenance routines.
  28  *
  29  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  30  *
  31  * Substantial contributions to this work comes from:
  32  *
  33  *              David S. Miller, <davem@davemloft.net>
  34  *              Stephen Hemminger <shemminger@osdl.org>
  35  *              Paul E. McKenney <paulmck@us.ibm.com>
  36  *              Patrick McHardy <kaber@trash.net>
  37  */
  38 
  39 #define VERSION "0.409"
  40 
  41 #include <linux/cache.h>
  42 #include <linux/uaccess.h>
  43 #include <linux/bitops.h>
  44 #include <linux/types.h>
  45 #include <linux/kernel.h>
  46 #include <linux/mm.h>
  47 #include <linux/string.h>
  48 #include <linux/socket.h>
  49 #include <linux/sockios.h>
  50 #include <linux/errno.h>
  51 #include <linux/in.h>
  52 #include <linux/inet.h>
  53 #include <linux/inetdevice.h>
  54 #include <linux/netdevice.h>
  55 #include <linux/if_arp.h>
  56 #include <linux/proc_fs.h>
  57 #include <linux/rcupdate.h>
  58 #include <linux/skbuff.h>
  59 #include <linux/netlink.h>
  60 #include <linux/init.h>
  61 #include <linux/list.h>
  62 #include <linux/slab.h>
  63 #include <linux/export.h>
  64 #include <linux/vmalloc.h>
  65 #include <linux/notifier.h>
  66 #include <net/net_namespace.h>
  67 #include <net/ip.h>
  68 #include <net/protocol.h>
  69 #include <net/route.h>
  70 #include <net/tcp.h>
  71 #include <net/sock.h>
  72 #include <net/ip_fib.h>
  73 #include <net/fib_notifier.h>
  74 #include <trace/events/fib.h>
  75 #include "fib_lookup.h"
  76 
  77 static int call_fib_entry_notifier(struct notifier_block *nb, struct net *net,
  78                                    enum fib_event_type event_type, u32 dst,
  79                                    int dst_len, struct fib_alias *fa)
  80 {
  81         struct fib_entry_notifier_info info = {
  82                 .dst = dst,
  83                 .dst_len = dst_len,
  84                 .fi = fa->fa_info,
  85                 .tos = fa->fa_tos,
  86                 .type = fa->fa_type,
  87                 .tb_id = fa->tb_id,
  88         };
  89         return call_fib4_notifier(nb, net, event_type, &info.info);
  90 }
  91 
  92 static int call_fib_entry_notifiers(struct net *net,
  93                                     enum fib_event_type event_type, u32 dst,
  94                                     int dst_len, struct fib_alias *fa,
  95                                     struct netlink_ext_ack *extack)
  96 {
  97         struct fib_entry_notifier_info info = {
  98                 .info.extack = extack,
  99                 .dst = dst,
 100                 .dst_len = dst_len,
 101                 .fi = fa->fa_info,
 102                 .tos = fa->fa_tos,
 103                 .type = fa->fa_type,
 104                 .tb_id = fa->tb_id,
 105         };
 106         return call_fib4_notifiers(net, event_type, &info.info);
 107 }
 108 
 109 #define MAX_STAT_DEPTH 32
 110 
 111 #define KEYLENGTH       (8*sizeof(t_key))
 112 #define KEY_MAX         ((t_key)~0)
 113 
 114 typedef unsigned int t_key;
 115 
 116 #define IS_TRIE(n)      ((n)->pos >= KEYLENGTH)
 117 #define IS_TNODE(n)     ((n)->bits)
 118 #define IS_LEAF(n)      (!(n)->bits)
 119 
 120 struct key_vector {
 121         t_key key;
 122         unsigned char pos;              /* 2log(KEYLENGTH) bits needed */
 123         unsigned char bits;             /* 2log(KEYLENGTH) bits needed */
 124         unsigned char slen;
 125         union {
 126                 /* This list pointer if valid if (pos | bits) == 0 (LEAF) */
 127                 struct hlist_head leaf;
 128                 /* This array is valid if (pos | bits) > 0 (TNODE) */
 129                 struct key_vector __rcu *tnode[0];
 130         };
 131 };
 132 
 133 struct tnode {
 134         struct rcu_head rcu;
 135         t_key empty_children;           /* KEYLENGTH bits needed */
 136         t_key full_children;            /* KEYLENGTH bits needed */
 137         struct key_vector __rcu *parent;
 138         struct key_vector kv[1];
 139 #define tn_bits kv[0].bits
 140 };
 141 
 142 #define TNODE_SIZE(n)   offsetof(struct tnode, kv[0].tnode[n])
 143 #define LEAF_SIZE       TNODE_SIZE(1)
 144 
 145 #ifdef CONFIG_IP_FIB_TRIE_STATS
 146 struct trie_use_stats {
 147         unsigned int gets;
 148         unsigned int backtrack;
 149         unsigned int semantic_match_passed;
 150         unsigned int semantic_match_miss;
 151         unsigned int null_node_hit;
 152         unsigned int resize_node_skipped;
 153 };
 154 #endif
 155 
 156 struct trie_stat {
 157         unsigned int totdepth;
 158         unsigned int maxdepth;
 159         unsigned int tnodes;
 160         unsigned int leaves;
 161         unsigned int nullpointers;
 162         unsigned int prefixes;
 163         unsigned int nodesizes[MAX_STAT_DEPTH];
 164 };
 165 
 166 struct trie {
 167         struct key_vector kv[1];
 168 #ifdef CONFIG_IP_FIB_TRIE_STATS
 169         struct trie_use_stats __percpu *stats;
 170 #endif
 171 };
 172 
 173 static struct key_vector *resize(struct trie *t, struct key_vector *tn);
 174 static unsigned int tnode_free_size;
 175 
 176 /*
 177  * synchronize_rcu after call_rcu for outstanding dirty memory; it should be
 178  * especially useful before resizing the root node with PREEMPT_NONE configs;
 179  * the value was obtained experimentally, aiming to avoid visible slowdown.
 180  */
 181 unsigned int sysctl_fib_sync_mem = 512 * 1024;
 182 unsigned int sysctl_fib_sync_mem_min = 64 * 1024;
 183 unsigned int sysctl_fib_sync_mem_max = 64 * 1024 * 1024;
 184 
 185 static struct kmem_cache *fn_alias_kmem __ro_after_init;
 186 static struct kmem_cache *trie_leaf_kmem __ro_after_init;
 187 
 188 static inline struct tnode *tn_info(struct key_vector *kv)
 189 {
 190         return container_of(kv, struct tnode, kv[0]);
 191 }
 192 
 193 /* caller must hold RTNL */
 194 #define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
 195 #define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
 196 
 197 /* caller must hold RCU read lock or RTNL */
 198 #define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
 199 #define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
 200 
 201 /* wrapper for rcu_assign_pointer */
 202 static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
 203 {
 204         if (n)
 205                 rcu_assign_pointer(tn_info(n)->parent, tp);
 206 }
 207 
 208 #define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(n)->parent, p)
 209 
 210 /* This provides us with the number of children in this node, in the case of a
 211  * leaf this will return 0 meaning none of the children are accessible.
 212  */
 213 static inline unsigned long child_length(const struct key_vector *tn)
 214 {
 215         return (1ul << tn->bits) & ~(1ul);
 216 }
 217 
 218 #define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
 219 
 220 static inline unsigned long get_index(t_key key, struct key_vector *kv)
 221 {
 222         unsigned long index = key ^ kv->key;
 223 
 224         if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
 225                 return 0;
 226 
 227         return index >> kv->pos;
 228 }
 229 
 230 /* To understand this stuff, an understanding of keys and all their bits is
 231  * necessary. Every node in the trie has a key associated with it, but not
 232  * all of the bits in that key are significant.
 233  *
 234  * Consider a node 'n' and its parent 'tp'.
 235  *
 236  * If n is a leaf, every bit in its key is significant. Its presence is
 237  * necessitated by path compression, since during a tree traversal (when
 238  * searching for a leaf - unless we are doing an insertion) we will completely
 239  * ignore all skipped bits we encounter. Thus we need to verify, at the end of
 240  * a potentially successful search, that we have indeed been walking the
 241  * correct key path.
 242  *
 243  * Note that we can never "miss" the correct key in the tree if present by
 244  * following the wrong path. Path compression ensures that segments of the key
 245  * that are the same for all keys with a given prefix are skipped, but the
 246  * skipped part *is* identical for each node in the subtrie below the skipped
 247  * bit! trie_insert() in this implementation takes care of that.
 248  *
 249  * if n is an internal node - a 'tnode' here, the various parts of its key
 250  * have many different meanings.
 251  *
 252  * Example:
 253  * _________________________________________________________________
 254  * | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
 255  * -----------------------------------------------------------------
 256  *  31  30  29  28  27  26  25  24  23  22  21  20  19  18  17  16
 257  *
 258  * _________________________________________________________________
 259  * | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
 260  * -----------------------------------------------------------------
 261  *  15  14  13  12  11  10   9   8   7   6   5   4   3   2   1   0
 262  *
 263  * tp->pos = 22
 264  * tp->bits = 3
 265  * n->pos = 13
 266  * n->bits = 4
 267  *
 268  * First, let's just ignore the bits that come before the parent tp, that is
 269  * the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
 270  * point we do not use them for anything.
 271  *
 272  * The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
 273  * index into the parent's child array. That is, they will be used to find
 274  * 'n' among tp's children.
 275  *
 276  * The bits from (n->pos + n->bits) to (tp->pos - 1) - "S" - are skipped bits
 277  * for the node n.
 278  *
 279  * All the bits we have seen so far are significant to the node n. The rest
 280  * of the bits are really not needed or indeed known in n->key.
 281  *
 282  * The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
 283  * n's child array, and will of course be different for each child.
 284  *
 285  * The rest of the bits, from 0 to (n->pos -1) - "u" - are completely unknown
 286  * at this point.
 287  */
 288 
 289 static const int halve_threshold = 25;
 290 static const int inflate_threshold = 50;
 291 static const int halve_threshold_root = 15;
 292 static const int inflate_threshold_root = 30;
 293 
 294 static void __alias_free_mem(struct rcu_head *head)
 295 {
 296         struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
 297         kmem_cache_free(fn_alias_kmem, fa);
 298 }
 299 
 300 static inline void alias_free_mem_rcu(struct fib_alias *fa)
 301 {
 302         call_rcu(&fa->rcu, __alias_free_mem);
 303 }
 304 
 305 #define TNODE_KMALLOC_MAX \
 306         ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct key_vector *))
 307 #define TNODE_VMALLOC_MAX \
 308         ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
 309 
 310 static void __node_free_rcu(struct rcu_head *head)
 311 {
 312         struct tnode *n = container_of(head, struct tnode, rcu);
 313 
 314         if (!n->tn_bits)
 315                 kmem_cache_free(trie_leaf_kmem, n);
 316         else
 317                 kvfree(n);
 318 }
 319 
 320 #define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
 321 
 322 static struct tnode *tnode_alloc(int bits)
 323 {
 324         size_t size;
 325 
 326         /* verify bits is within bounds */
 327         if (bits > TNODE_VMALLOC_MAX)
 328                 return NULL;
 329 
 330         /* determine size and verify it is non-zero and didn't overflow */
 331         size = TNODE_SIZE(1ul << bits);
 332 
 333         if (size <= PAGE_SIZE)
 334                 return kzalloc(size, GFP_KERNEL);
 335         else
 336                 return vzalloc(size);
 337 }
 338 
 339 static inline void empty_child_inc(struct key_vector *n)
 340 {
 341         tn_info(n)->empty_children++;
 342 
 343         if (!tn_info(n)->empty_children)
 344                 tn_info(n)->full_children++;
 345 }
 346 
 347 static inline void empty_child_dec(struct key_vector *n)
 348 {
 349         if (!tn_info(n)->empty_children)
 350                 tn_info(n)->full_children--;
 351 
 352         tn_info(n)->empty_children--;
 353 }
 354 
 355 static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
 356 {
 357         struct key_vector *l;
 358         struct tnode *kv;
 359 
 360         kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
 361         if (!kv)
 362                 return NULL;
 363 
 364         /* initialize key vector */
 365         l = kv->kv;
 366         l->key = key;
 367         l->pos = 0;
 368         l->bits = 0;
 369         l->slen = fa->fa_slen;
 370 
 371         /* link leaf to fib alias */
 372         INIT_HLIST_HEAD(&l->leaf);
 373         hlist_add_head(&fa->fa_list, &l->leaf);
 374 
 375         return l;
 376 }
 377 
 378 static struct key_vector *tnode_new(t_key key, int pos, int bits)
 379 {
 380         unsigned int shift = pos + bits;
 381         struct key_vector *tn;
 382         struct tnode *tnode;
 383 
 384         /* verify bits and pos their msb bits clear and values are valid */
 385         BUG_ON(!bits || (shift > KEYLENGTH));
 386 
 387         tnode = tnode_alloc(bits);
 388         if (!tnode)
 389                 return NULL;
 390 
 391         pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
 392                  sizeof(struct key_vector *) << bits);
 393 
 394         if (bits == KEYLENGTH)
 395                 tnode->full_children = 1;
 396         else
 397                 tnode->empty_children = 1ul << bits;
 398 
 399         tn = tnode->kv;
 400         tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
 401         tn->pos = pos;
 402         tn->bits = bits;
 403         tn->slen = pos;
 404 
 405         return tn;
 406 }
 407 
 408 /* Check whether a tnode 'n' is "full", i.e. it is an internal node
 409  * and no bits are skipped. See discussion in dyntree paper p. 6
 410  */
 411 static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
 412 {
 413         return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
 414 }
 415 
 416 /* Add a child at position i overwriting the old value.
 417  * Update the value of full_children and empty_children.
 418  */
 419 static void put_child(struct key_vector *tn, unsigned long i,
 420                       struct key_vector *n)
 421 {
 422         struct key_vector *chi = get_child(tn, i);
 423         int isfull, wasfull;
 424 
 425         BUG_ON(i >= child_length(tn));
 426 
 427         /* update emptyChildren, overflow into fullChildren */
 428         if (!n && chi)
 429                 empty_child_inc(tn);
 430         if (n && !chi)
 431                 empty_child_dec(tn);
 432 
 433         /* update fullChildren */
 434         wasfull = tnode_full(tn, chi);
 435         isfull = tnode_full(tn, n);
 436 
 437         if (wasfull && !isfull)
 438                 tn_info(tn)->full_children--;
 439         else if (!wasfull && isfull)
 440                 tn_info(tn)->full_children++;
 441 
 442         if (n && (tn->slen < n->slen))
 443                 tn->slen = n->slen;
 444 
 445         rcu_assign_pointer(tn->tnode[i], n);
 446 }
 447 
 448 static void update_children(struct key_vector *tn)
 449 {
 450         unsigned long i;
 451 
 452         /* update all of the child parent pointers */
 453         for (i = child_length(tn); i;) {
 454                 struct key_vector *inode = get_child(tn, --i);
 455 
 456                 if (!inode)
 457                         continue;
 458 
 459                 /* Either update the children of a tnode that
 460                  * already belongs to us or update the child
 461                  * to point to ourselves.
 462                  */
 463                 if (node_parent(inode) == tn)
 464                         update_children(inode);
 465                 else
 466                         node_set_parent(inode, tn);
 467         }
 468 }
 469 
 470 static inline void put_child_root(struct key_vector *tp, t_key key,
 471                                   struct key_vector *n)
 472 {
 473         if (IS_TRIE(tp))
 474                 rcu_assign_pointer(tp->tnode[0], n);
 475         else
 476                 put_child(tp, get_index(key, tp), n);
 477 }
 478 
 479 static inline void tnode_free_init(struct key_vector *tn)
 480 {
 481         tn_info(tn)->rcu.next = NULL;
 482 }
 483 
 484 static inline void tnode_free_append(struct key_vector *tn,
 485                                      struct key_vector *n)
 486 {
 487         tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
 488         tn_info(tn)->rcu.next = &tn_info(n)->rcu;
 489 }
 490 
 491 static void tnode_free(struct key_vector *tn)
 492 {
 493         struct callback_head *head = &tn_info(tn)->rcu;
 494 
 495         while (head) {
 496                 head = head->next;
 497                 tnode_free_size += TNODE_SIZE(1ul << tn->bits);
 498                 node_free(tn);
 499 
 500                 tn = container_of(head, struct tnode, rcu)->kv;
 501         }
 502 
 503         if (tnode_free_size >= sysctl_fib_sync_mem) {
 504                 tnode_free_size = 0;
 505                 synchronize_rcu();
 506         }
 507 }
 508 
 509 static struct key_vector *replace(struct trie *t,
 510                                   struct key_vector *oldtnode,
 511                                   struct key_vector *tn)
 512 {
 513         struct key_vector *tp = node_parent(oldtnode);
 514         unsigned long i;
 515 
 516         /* setup the parent pointer out of and back into this node */
 517         NODE_INIT_PARENT(tn, tp);
 518         put_child_root(tp, tn->key, tn);
 519 
 520         /* update all of the child parent pointers */
 521         update_children(tn);
 522 
 523         /* all pointers should be clean so we are done */
 524         tnode_free(oldtnode);
 525 
 526         /* resize children now that oldtnode is freed */
 527         for (i = child_length(tn); i;) {
 528                 struct key_vector *inode = get_child(tn, --i);
 529 
 530                 /* resize child node */
 531                 if (tnode_full(tn, inode))
 532                         tn = resize(t, inode);
 533         }
 534 
 535         return tp;
 536 }
 537 
 538 static struct key_vector *inflate(struct trie *t,
 539                                   struct key_vector *oldtnode)
 540 {
 541         struct key_vector *tn;
 542         unsigned long i;
 543         t_key m;
 544 
 545         pr_debug("In inflate\n");
 546 
 547         tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
 548         if (!tn)
 549                 goto notnode;
 550 
 551         /* prepare oldtnode to be freed */
 552         tnode_free_init(oldtnode);
 553 
 554         /* Assemble all of the pointers in our cluster, in this case that
 555          * represents all of the pointers out of our allocated nodes that
 556          * point to existing tnodes and the links between our allocated
 557          * nodes.
 558          */
 559         for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
 560                 struct key_vector *inode = get_child(oldtnode, --i);
 561                 struct key_vector *node0, *node1;
 562                 unsigned long j, k;
 563 
 564                 /* An empty child */
 565                 if (!inode)
 566                         continue;
 567 
 568                 /* A leaf or an internal node with skipped bits */
 569                 if (!tnode_full(oldtnode, inode)) {
 570                         put_child(tn, get_index(inode->key, tn), inode);
 571                         continue;
 572                 }
 573 
 574                 /* drop the node in the old tnode free list */
 575                 tnode_free_append(oldtnode, inode);
 576 
 577                 /* An internal node with two children */
 578                 if (inode->bits == 1) {
 579                         put_child(tn, 2 * i + 1, get_child(inode, 1));
 580                         put_child(tn, 2 * i, get_child(inode, 0));
 581                         continue;
 582                 }
 583 
 584                 /* We will replace this node 'inode' with two new
 585                  * ones, 'node0' and 'node1', each with half of the
 586                  * original children. The two new nodes will have
 587                  * a position one bit further down the key and this
 588                  * means that the "significant" part of their keys
 589                  * (see the discussion near the top of this file)
 590                  * will differ by one bit, which will be "0" in
 591                  * node0's key and "1" in node1's key. Since we are
 592                  * moving the key position by one step, the bit that
 593                  * we are moving away from - the bit at position
 594                  * (tn->pos) - is the one that will differ between
 595                  * node0 and node1. So... we synthesize that bit in the
 596                  * two new keys.
 597                  */
 598                 node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
 599                 if (!node1)
 600                         goto nomem;
 601                 node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
 602 
 603                 tnode_free_append(tn, node1);
 604                 if (!node0)
 605                         goto nomem;
 606                 tnode_free_append(tn, node0);
 607 
 608                 /* populate child pointers in new nodes */
 609                 for (k = child_length(inode), j = k / 2; j;) {
 610                         put_child(node1, --j, get_child(inode, --k));
 611                         put_child(node0, j, get_child(inode, j));
 612                         put_child(node1, --j, get_child(inode, --k));
 613                         put_child(node0, j, get_child(inode, j));
 614                 }
 615 
 616                 /* link new nodes to parent */
 617                 NODE_INIT_PARENT(node1, tn);
 618                 NODE_INIT_PARENT(node0, tn);
 619 
 620                 /* link parent to nodes */
 621                 put_child(tn, 2 * i + 1, node1);
 622                 put_child(tn, 2 * i, node0);
 623         }
 624 
 625         /* setup the parent pointers into and out of this node */
 626         return replace(t, oldtnode, tn);
 627 nomem:
 628         /* all pointers should be clean so we are done */
 629         tnode_free(tn);
 630 notnode:
 631         return NULL;
 632 }
 633 
 634 static struct key_vector *halve(struct trie *t,
 635                                 struct key_vector *oldtnode)
 636 {
 637         struct key_vector *tn;
 638         unsigned long i;
 639 
 640         pr_debug("In halve\n");
 641 
 642         tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
 643         if (!tn)
 644                 goto notnode;
 645 
 646         /* prepare oldtnode to be freed */
 647         tnode_free_init(oldtnode);
 648 
 649         /* Assemble all of the pointers in our cluster, in this case that
 650          * represents all of the pointers out of our allocated nodes that
 651          * point to existing tnodes and the links between our allocated
 652          * nodes.
 653          */
 654         for (i = child_length(oldtnode); i;) {
 655                 struct key_vector *node1 = get_child(oldtnode, --i);
 656                 struct key_vector *node0 = get_child(oldtnode, --i);
 657                 struct key_vector *inode;
 658 
 659                 /* At least one of the children is empty */
 660                 if (!node1 || !node0) {
 661                         put_child(tn, i / 2, node1 ? : node0);
 662                         continue;
 663                 }
 664 
 665                 /* Two nonempty children */
 666                 inode = tnode_new(node0->key, oldtnode->pos, 1);
 667                 if (!inode)
 668                         goto nomem;
 669                 tnode_free_append(tn, inode);
 670 
 671                 /* initialize pointers out of node */
 672                 put_child(inode, 1, node1);
 673                 put_child(inode, 0, node0);
 674                 NODE_INIT_PARENT(inode, tn);
 675 
 676                 /* link parent to node */
 677                 put_child(tn, i / 2, inode);
 678         }
 679 
 680         /* setup the parent pointers into and out of this node */
 681         return replace(t, oldtnode, tn);
 682 nomem:
 683         /* all pointers should be clean so we are done */
 684         tnode_free(tn);
 685 notnode:
 686         return NULL;
 687 }
 688 
 689 static struct key_vector *collapse(struct trie *t,
 690                                    struct key_vector *oldtnode)
 691 {
 692         struct key_vector *n, *tp;
 693         unsigned long i;
 694 
 695         /* scan the tnode looking for that one child that might still exist */
 696         for (n = NULL, i = child_length(oldtnode); !n && i;)
 697                 n = get_child(oldtnode, --i);
 698 
 699         /* compress one level */
 700         tp = node_parent(oldtnode);
 701         put_child_root(tp, oldtnode->key, n);
 702         node_set_parent(n, tp);
 703 
 704         /* drop dead node */
 705         node_free(oldtnode);
 706 
 707         return tp;
 708 }
 709 
 710 static unsigned char update_suffix(struct key_vector *tn)
 711 {
 712         unsigned char slen = tn->pos;
 713         unsigned long stride, i;
 714         unsigned char slen_max;
 715 
 716         /* only vector 0 can have a suffix length greater than or equal to
 717          * tn->pos + tn->bits, the second highest node will have a suffix
 718          * length at most of tn->pos + tn->bits - 1
 719          */
 720         slen_max = min_t(unsigned char, tn->pos + tn->bits - 1, tn->slen);
 721 
 722         /* search though the list of children looking for nodes that might
 723          * have a suffix greater than the one we currently have.  This is
 724          * why we start with a stride of 2 since a stride of 1 would
 725          * represent the nodes with suffix length equal to tn->pos
 726          */
 727         for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
 728                 struct key_vector *n = get_child(tn, i);
 729 
 730                 if (!n || (n->slen <= slen))
 731                         continue;
 732 
 733                 /* update stride and slen based on new value */
 734                 stride <<= (n->slen - slen);
 735                 slen = n->slen;
 736                 i &= ~(stride - 1);
 737 
 738                 /* stop searching if we have hit the maximum possible value */
 739                 if (slen >= slen_max)
 740                         break;
 741         }
 742 
 743         tn->slen = slen;
 744 
 745         return slen;
 746 }
 747 
 748 /* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
 749  * the Helsinki University of Technology and Matti Tikkanen of Nokia
 750  * Telecommunications, page 6:
 751  * "A node is doubled if the ratio of non-empty children to all
 752  * children in the *doubled* node is at least 'high'."
 753  *
 754  * 'high' in this instance is the variable 'inflate_threshold'. It
 755  * is expressed as a percentage, so we multiply it with
 756  * child_length() and instead of multiplying by 2 (since the
 757  * child array will be doubled by inflate()) and multiplying
 758  * the left-hand side by 100 (to handle the percentage thing) we
 759  * multiply the left-hand side by 50.
 760  *
 761  * The left-hand side may look a bit weird: child_length(tn)
 762  * - tn->empty_children is of course the number of non-null children
 763  * in the current node. tn->full_children is the number of "full"
 764  * children, that is non-null tnodes with a skip value of 0.
 765  * All of those will be doubled in the resulting inflated tnode, so
 766  * we just count them one extra time here.
 767  *
 768  * A clearer way to write this would be:
 769  *
 770  * to_be_doubled = tn->full_children;
 771  * not_to_be_doubled = child_length(tn) - tn->empty_children -
 772  *     tn->full_children;
 773  *
 774  * new_child_length = child_length(tn) * 2;
 775  *
 776  * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
 777  *      new_child_length;
 778  * if (new_fill_factor >= inflate_threshold)
 779  *
 780  * ...and so on, tho it would mess up the while () loop.
 781  *
 782  * anyway,
 783  * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
 784  *      inflate_threshold
 785  *
 786  * avoid a division:
 787  * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
 788  *      inflate_threshold * new_child_length
 789  *
 790  * expand not_to_be_doubled and to_be_doubled, and shorten:
 791  * 100 * (child_length(tn) - tn->empty_children +
 792  *    tn->full_children) >= inflate_threshold * new_child_length
 793  *
 794  * expand new_child_length:
 795  * 100 * (child_length(tn) - tn->empty_children +
 796  *    tn->full_children) >=
 797  *      inflate_threshold * child_length(tn) * 2
 798  *
 799  * shorten again:
 800  * 50 * (tn->full_children + child_length(tn) -
 801  *    tn->empty_children) >= inflate_threshold *
 802  *    child_length(tn)
 803  *
 804  */
 805 static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
 806 {
 807         unsigned long used = child_length(tn);
 808         unsigned long threshold = used;
 809 
 810         /* Keep root node larger */
 811         threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
 812         used -= tn_info(tn)->empty_children;
 813         used += tn_info(tn)->full_children;
 814 
 815         /* if bits == KEYLENGTH then pos = 0, and will fail below */
 816 
 817         return (used > 1) && tn->pos && ((50 * used) >= threshold);
 818 }
 819 
 820 static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
 821 {
 822         unsigned long used = child_length(tn);
 823         unsigned long threshold = used;
 824 
 825         /* Keep root node larger */
 826         threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
 827         used -= tn_info(tn)->empty_children;
 828 
 829         /* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
 830 
 831         return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
 832 }
 833 
 834 static inline bool should_collapse(struct key_vector *tn)
 835 {
 836         unsigned long used = child_length(tn);
 837 
 838         used -= tn_info(tn)->empty_children;
 839 
 840         /* account for bits == KEYLENGTH case */
 841         if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
 842                 used -= KEY_MAX;
 843 
 844         /* One child or none, time to drop us from the trie */
 845         return used < 2;
 846 }
 847 
 848 #define MAX_WORK 10
 849 static struct key_vector *resize(struct trie *t, struct key_vector *tn)
 850 {
 851 #ifdef CONFIG_IP_FIB_TRIE_STATS
 852         struct trie_use_stats __percpu *stats = t->stats;
 853 #endif
 854         struct key_vector *tp = node_parent(tn);
 855         unsigned long cindex = get_index(tn->key, tp);
 856         int max_work = MAX_WORK;
 857 
 858         pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
 859                  tn, inflate_threshold, halve_threshold);
 860 
 861         /* track the tnode via the pointer from the parent instead of
 862          * doing it ourselves.  This way we can let RCU fully do its
 863          * thing without us interfering
 864          */
 865         BUG_ON(tn != get_child(tp, cindex));
 866 
 867         /* Double as long as the resulting node has a number of
 868          * nonempty nodes that are above the threshold.
 869          */
 870         while (should_inflate(tp, tn) && max_work) {
 871                 tp = inflate(t, tn);
 872                 if (!tp) {
 873 #ifdef CONFIG_IP_FIB_TRIE_STATS
 874                         this_cpu_inc(stats->resize_node_skipped);
 875 #endif
 876                         break;
 877                 }
 878 
 879                 max_work--;
 880                 tn = get_child(tp, cindex);
 881         }
 882 
 883         /* update parent in case inflate failed */
 884         tp = node_parent(tn);
 885 
 886         /* Return if at least one inflate is run */
 887         if (max_work != MAX_WORK)
 888                 return tp;
 889 
 890         /* Halve as long as the number of empty children in this
 891          * node is above threshold.
 892          */
 893         while (should_halve(tp, tn) && max_work) {
 894                 tp = halve(t, tn);
 895                 if (!tp) {
 896 #ifdef CONFIG_IP_FIB_TRIE_STATS
 897                         this_cpu_inc(stats->resize_node_skipped);
 898 #endif
 899                         break;
 900                 }
 901 
 902                 max_work--;
 903                 tn = get_child(tp, cindex);
 904         }
 905 
 906         /* Only one child remains */
 907         if (should_collapse(tn))
 908                 return collapse(t, tn);
 909 
 910         /* update parent in case halve failed */
 911         return node_parent(tn);
 912 }
 913 
 914 static void node_pull_suffix(struct key_vector *tn, unsigned char slen)
 915 {
 916         unsigned char node_slen = tn->slen;
 917 
 918         while ((node_slen > tn->pos) && (node_slen > slen)) {
 919                 slen = update_suffix(tn);
 920                 if (node_slen == slen)
 921                         break;
 922 
 923                 tn = node_parent(tn);
 924                 node_slen = tn->slen;
 925         }
 926 }
 927 
 928 static void node_push_suffix(struct key_vector *tn, unsigned char slen)
 929 {
 930         while (tn->slen < slen) {
 931                 tn->slen = slen;
 932                 tn = node_parent(tn);
 933         }
 934 }
 935 
 936 /* rcu_read_lock needs to be hold by caller from readside */
 937 static struct key_vector *fib_find_node(struct trie *t,
 938                                         struct key_vector **tp, u32 key)
 939 {
 940         struct key_vector *pn, *n = t->kv;
 941         unsigned long index = 0;
 942 
 943         do {
 944                 pn = n;
 945                 n = get_child_rcu(n, index);
 946 
 947                 if (!n)
 948                         break;
 949 
 950                 index = get_cindex(key, n);
 951 
 952                 /* This bit of code is a bit tricky but it combines multiple
 953                  * checks into a single check.  The prefix consists of the
 954                  * prefix plus zeros for the bits in the cindex. The index
 955                  * is the difference between the key and this value.  From
 956                  * this we can actually derive several pieces of data.
 957                  *   if (index >= (1ul << bits))
 958                  *     we have a mismatch in skip bits and failed
 959                  *   else
 960                  *     we know the value is cindex
 961                  *
 962                  * This check is safe even if bits == KEYLENGTH due to the
 963                  * fact that we can only allocate a node with 32 bits if a
 964                  * long is greater than 32 bits.
 965                  */
 966                 if (index >= (1ul << n->bits)) {
 967                         n = NULL;
 968                         break;
 969                 }
 970 
 971                 /* keep searching until we find a perfect match leaf or NULL */
 972         } while (IS_TNODE(n));
 973 
 974         *tp = pn;
 975 
 976         return n;
 977 }
 978 
 979 /* Return the first fib alias matching TOS with
 980  * priority less than or equal to PRIO.
 981  */
 982 static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
 983                                         u8 tos, u32 prio, u32 tb_id)
 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 (fa->fa_tos > tos)
1000                         continue;
1001                 if (fa->fa_info->fib_priority >= prio || fa->fa_tos < tos)
1002                         return fa;
1003         }
1004 
1005         return NULL;
1006 }
1007 
1008 static void trie_rebalance(struct trie *t, struct key_vector *tn)
1009 {
1010         while (!IS_TRIE(tn))
1011                 tn = resize(t, tn);
1012 }
1013 
1014 static int fib_insert_node(struct trie *t, struct key_vector *tp,
1015                            struct fib_alias *new, t_key key)
1016 {
1017         struct key_vector *n, *l;
1018 
1019         l = leaf_new(key, new);
1020         if (!l)
1021                 goto noleaf;
1022 
1023         /* retrieve child from parent node */
1024         n = get_child(tp, get_index(key, tp));
1025 
1026         /* Case 2: n is a LEAF or a TNODE and the key doesn't match.
1027          *
1028          *  Add a new tnode here
1029          *  first tnode need some special handling
1030          *  leaves us in position for handling as case 3
1031          */
1032         if (n) {
1033                 struct key_vector *tn;
1034 
1035                 tn = tnode_new(key, __fls(key ^ n->key), 1);
1036                 if (!tn)
1037                         goto notnode;
1038 
1039                 /* initialize routes out of node */
1040                 NODE_INIT_PARENT(tn, tp);
1041                 put_child(tn, get_index(key, tn) ^ 1, n);
1042 
1043                 /* start adding routes into the node */
1044                 put_child_root(tp, key, tn);
1045                 node_set_parent(n, tn);
1046 
1047                 /* parent now has a NULL spot where the leaf can go */
1048                 tp = tn;
1049         }
1050 
1051         /* Case 3: n is NULL, and will just insert a new leaf */
1052         node_push_suffix(tp, new->fa_slen);
1053         NODE_INIT_PARENT(l, tp);
1054         put_child_root(tp, key, l);
1055         trie_rebalance(t, tp);
1056 
1057         return 0;
1058 notnode:
1059         node_free(l);
1060 noleaf:
1061         return -ENOMEM;
1062 }
1063 
1064 /* fib notifier for ADD is sent before calling fib_insert_alias with
1065  * the expectation that the only possible failure ENOMEM
1066  */
1067 static int fib_insert_alias(struct trie *t, struct key_vector *tp,
1068                             struct key_vector *l, struct fib_alias *new,
1069                             struct fib_alias *fa, t_key key)
1070 {
1071         if (!l)
1072                 return fib_insert_node(t, tp, new, key);
1073 
1074         if (fa) {
1075                 hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
1076         } else {
1077                 struct fib_alias *last;
1078 
1079                 hlist_for_each_entry(last, &l->leaf, fa_list) {
1080                         if (new->fa_slen < last->fa_slen)
1081                                 break;
1082                         if ((new->fa_slen == last->fa_slen) &&
1083                             (new->tb_id > last->tb_id))
1084                                 break;
1085                         fa = last;
1086                 }
1087 
1088                 if (fa)
1089                         hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
1090                 else
1091                         hlist_add_head_rcu(&new->fa_list, &l->leaf);
1092         }
1093 
1094         /* if we added to the tail node then we need to update slen */
1095         if (l->slen < new->fa_slen) {
1096                 l->slen = new->fa_slen;
1097                 node_push_suffix(tp, new->fa_slen);
1098         }
1099 
1100         return 0;
1101 }
1102 
1103 static bool fib_valid_key_len(u32 key, u8 plen, struct netlink_ext_ack *extack)
1104 {
1105         if (plen > KEYLENGTH) {
1106                 NL_SET_ERR_MSG(extack, "Invalid prefix length");
1107                 return false;
1108         }
1109 
1110         if ((plen < KEYLENGTH) && (key << plen)) {
1111                 NL_SET_ERR_MSG(extack,
1112                                "Invalid prefix for given prefix length");
1113                 return false;
1114         }
1115 
1116         return true;
1117 }
1118 
1119 /* Caller must hold RTNL. */
1120 int fib_table_insert(struct net *net, struct fib_table *tb,
1121                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1122 {
1123         enum fib_event_type event = FIB_EVENT_ENTRY_ADD;
1124         struct trie *t = (struct trie *)tb->tb_data;
1125         struct fib_alias *fa, *new_fa;
1126         struct key_vector *l, *tp;
1127         u16 nlflags = NLM_F_EXCL;
1128         struct fib_info *fi;
1129         u8 plen = cfg->fc_dst_len;
1130         u8 slen = KEYLENGTH - plen;
1131         u8 tos = cfg->fc_tos;
1132         u32 key;
1133         int err;
1134 
1135         key = ntohl(cfg->fc_dst);
1136 
1137         if (!fib_valid_key_len(key, plen, extack))
1138                 return -EINVAL;
1139 
1140         pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
1141 
1142         fi = fib_create_info(cfg, extack);
1143         if (IS_ERR(fi)) {
1144                 err = PTR_ERR(fi);
1145                 goto err;
1146         }
1147 
1148         l = fib_find_node(t, &tp, key);
1149         fa = l ? fib_find_alias(&l->leaf, slen, tos, fi->fib_priority,
1150                                 tb->tb_id) : NULL;
1151 
1152         /* Now fa, if non-NULL, points to the first fib alias
1153          * with the same keys [prefix,tos,priority], if such key already
1154          * exists or to the node before which we will insert new one.
1155          *
1156          * If fa is NULL, we will need to allocate a new one and
1157          * insert to the tail of the section matching the suffix length
1158          * of the new alias.
1159          */
1160 
1161         if (fa && fa->fa_tos == tos &&
1162             fa->fa_info->fib_priority == fi->fib_priority) {
1163                 struct fib_alias *fa_first, *fa_match;
1164 
1165                 err = -EEXIST;
1166                 if (cfg->fc_nlflags & NLM_F_EXCL)
1167                         goto out;
1168 
1169                 nlflags &= ~NLM_F_EXCL;
1170 
1171                 /* We have 2 goals:
1172                  * 1. Find exact match for type, scope, fib_info to avoid
1173                  * duplicate routes
1174                  * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
1175                  */
1176                 fa_match = NULL;
1177                 fa_first = fa;
1178                 hlist_for_each_entry_from(fa, fa_list) {
1179                         if ((fa->fa_slen != slen) ||
1180                             (fa->tb_id != tb->tb_id) ||
1181                             (fa->fa_tos != tos))
1182                                 break;
1183                         if (fa->fa_info->fib_priority != fi->fib_priority)
1184                                 break;
1185                         if (fa->fa_type == cfg->fc_type &&
1186                             fa->fa_info == fi) {
1187                                 fa_match = fa;
1188                                 break;
1189                         }
1190                 }
1191 
1192                 if (cfg->fc_nlflags & NLM_F_REPLACE) {
1193                         struct fib_info *fi_drop;
1194                         u8 state;
1195 
1196                         nlflags |= NLM_F_REPLACE;
1197                         fa = fa_first;
1198                         if (fa_match) {
1199                                 if (fa == fa_match)
1200                                         err = 0;
1201                                 goto out;
1202                         }
1203                         err = -ENOBUFS;
1204                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1205                         if (!new_fa)
1206                                 goto out;
1207 
1208                         fi_drop = fa->fa_info;
1209                         new_fa->fa_tos = fa->fa_tos;
1210                         new_fa->fa_info = fi;
1211                         new_fa->fa_type = cfg->fc_type;
1212                         state = fa->fa_state;
1213                         new_fa->fa_state = state & ~FA_S_ACCESSED;
1214                         new_fa->fa_slen = fa->fa_slen;
1215                         new_fa->tb_id = tb->tb_id;
1216                         new_fa->fa_default = -1;
1217 
1218                         err = call_fib_entry_notifiers(net,
1219                                                        FIB_EVENT_ENTRY_REPLACE,
1220                                                        key, plen, new_fa,
1221                                                        extack);
1222                         if (err)
1223                                 goto out_free_new_fa;
1224 
1225                         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
1226                                   tb->tb_id, &cfg->fc_nlinfo, nlflags);
1227 
1228                         hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
1229 
1230                         alias_free_mem_rcu(fa);
1231 
1232                         fib_release_info(fi_drop);
1233                         if (state & FA_S_ACCESSED)
1234                                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1235 
1236                         goto succeeded;
1237                 }
1238                 /* Error if we find a perfect match which
1239                  * uses the same scope, type, and nexthop
1240                  * information.
1241                  */
1242                 if (fa_match)
1243                         goto out;
1244 
1245                 if (cfg->fc_nlflags & NLM_F_APPEND) {
1246                         event = FIB_EVENT_ENTRY_APPEND;
1247                         nlflags |= NLM_F_APPEND;
1248                 } else {
1249                         fa = fa_first;
1250                 }
1251         }
1252         err = -ENOENT;
1253         if (!(cfg->fc_nlflags & NLM_F_CREATE))
1254                 goto out;
1255 
1256         nlflags |= NLM_F_CREATE;
1257         err = -ENOBUFS;
1258         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1259         if (!new_fa)
1260                 goto out;
1261 
1262         new_fa->fa_info = fi;
1263         new_fa->fa_tos = tos;
1264         new_fa->fa_type = cfg->fc_type;
1265         new_fa->fa_state = 0;
1266         new_fa->fa_slen = slen;
1267         new_fa->tb_id = tb->tb_id;
1268         new_fa->fa_default = -1;
1269 
1270         err = call_fib_entry_notifiers(net, event, key, plen, new_fa, extack);
1271         if (err)
1272                 goto out_free_new_fa;
1273 
1274         /* Insert new entry to the list. */
1275         err = fib_insert_alias(t, tp, l, new_fa, fa, key);
1276         if (err)
1277                 goto out_fib_notif;
1278 
1279         if (!plen)
1280                 tb->tb_num_default++;
1281 
1282         rt_cache_flush(cfg->fc_nlinfo.nl_net);
1283         rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
1284                   &cfg->fc_nlinfo, nlflags);
1285 succeeded:
1286         return 0;
1287 
1288 out_fib_notif:
1289         /* notifier was sent that entry would be added to trie, but
1290          * the add failed and need to recover. Only failure for
1291          * fib_insert_alias is ENOMEM.
1292          */
1293         NL_SET_ERR_MSG(extack, "Failed to insert route into trie");
1294         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key,
1295                                  plen, new_fa, NULL);
1296 out_free_new_fa:
1297         kmem_cache_free(fn_alias_kmem, new_fa);
1298 out:
1299         fib_release_info(fi);
1300 err:
1301         return err;
1302 }
1303 
1304 static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
1305 {
1306         t_key prefix = n->key;
1307 
1308         return (key ^ prefix) & (prefix | -prefix);
1309 }
1310 
1311 /* should be called with rcu_read_lock */
1312 int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
1313                      struct fib_result *res, int fib_flags)
1314 {
1315         struct trie *t = (struct trie *) tb->tb_data;
1316 #ifdef CONFIG_IP_FIB_TRIE_STATS
1317         struct trie_use_stats __percpu *stats = t->stats;
1318 #endif
1319         const t_key key = ntohl(flp->daddr);
1320         struct key_vector *n, *pn;
1321         struct fib_alias *fa;
1322         unsigned long index;
1323         t_key cindex;
1324 
1325         pn = t->kv;
1326         cindex = 0;
1327 
1328         n = get_child_rcu(pn, cindex);
1329         if (!n) {
1330                 trace_fib_table_lookup(tb->tb_id, flp, NULL, -EAGAIN);
1331                 return -EAGAIN;
1332         }
1333 
1334 #ifdef CONFIG_IP_FIB_TRIE_STATS
1335         this_cpu_inc(stats->gets);
1336 #endif
1337 
1338         /* Step 1: Travel to the longest prefix match in the trie */
1339         for (;;) {
1340                 index = get_cindex(key, n);
1341 
1342                 /* This bit of code is a bit tricky but it combines multiple
1343                  * checks into a single check.  The prefix consists of the
1344                  * prefix plus zeros for the "bits" in the prefix. The index
1345                  * is the difference between the key and this value.  From
1346                  * this we can actually derive several pieces of data.
1347                  *   if (index >= (1ul << bits))
1348                  *     we have a mismatch in skip bits and failed
1349                  *   else
1350                  *     we know the value is cindex
1351                  *
1352                  * This check is safe even if bits == KEYLENGTH due to the
1353                  * fact that we can only allocate a node with 32 bits if a
1354                  * long is greater than 32 bits.
1355                  */
1356                 if (index >= (1ul << n->bits))
1357                         break;
1358 
1359                 /* we have found a leaf. Prefixes have already been compared */
1360                 if (IS_LEAF(n))
1361                         goto found;
1362 
1363                 /* only record pn and cindex if we are going to be chopping
1364                  * bits later.  Otherwise we are just wasting cycles.
1365                  */
1366                 if (n->slen > n->pos) {
1367                         pn = n;
1368                         cindex = index;
1369                 }
1370 
1371                 n = get_child_rcu(n, index);
1372                 if (unlikely(!n))
1373                         goto backtrace;
1374         }
1375 
1376         /* Step 2: Sort out leaves and begin backtracing for longest prefix */
1377         for (;;) {
1378                 /* record the pointer where our next node pointer is stored */
1379                 struct key_vector __rcu **cptr = n->tnode;
1380 
1381                 /* This test verifies that none of the bits that differ
1382                  * between the key and the prefix exist in the region of
1383                  * the lsb and higher in the prefix.
1384                  */
1385                 if (unlikely(prefix_mismatch(key, n)) || (n->slen == n->pos))
1386                         goto backtrace;
1387 
1388                 /* exit out and process leaf */
1389                 if (unlikely(IS_LEAF(n)))
1390                         break;
1391 
1392                 /* Don't bother recording parent info.  Since we are in
1393                  * prefix match mode we will have to come back to wherever
1394                  * we started this traversal anyway
1395                  */
1396 
1397                 while ((n = rcu_dereference(*cptr)) == NULL) {
1398 backtrace:
1399 #ifdef CONFIG_IP_FIB_TRIE_STATS
1400                         if (!n)
1401                                 this_cpu_inc(stats->null_node_hit);
1402 #endif
1403                         /* If we are at cindex 0 there are no more bits for
1404                          * us to strip at this level so we must ascend back
1405                          * up one level to see if there are any more bits to
1406                          * be stripped there.
1407                          */
1408                         while (!cindex) {
1409                                 t_key pkey = pn->key;
1410 
1411                                 /* If we don't have a parent then there is
1412                                  * nothing for us to do as we do not have any
1413                                  * further nodes to parse.
1414                                  */
1415                                 if (IS_TRIE(pn)) {
1416                                         trace_fib_table_lookup(tb->tb_id, flp,
1417                                                                NULL, -EAGAIN);
1418                                         return -EAGAIN;
1419                                 }
1420 #ifdef CONFIG_IP_FIB_TRIE_STATS
1421                                 this_cpu_inc(stats->backtrack);
1422 #endif
1423                                 /* Get Child's index */
1424                                 pn = node_parent_rcu(pn);
1425                                 cindex = get_index(pkey, pn);
1426                         }
1427 
1428                         /* strip the least significant bit from the cindex */
1429                         cindex &= cindex - 1;
1430 
1431                         /* grab pointer for next child node */
1432                         cptr = &pn->tnode[cindex];
1433                 }
1434         }
1435 
1436 found:
1437         /* this line carries forward the xor from earlier in the function */
1438         index = key ^ n->key;
1439 
1440         /* Step 3: Process the leaf, if that fails fall back to backtracing */
1441         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
1442                 struct fib_info *fi = fa->fa_info;
1443                 int nhsel, err;
1444 
1445                 if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) {
1446                         if (index >= (1ul << fa->fa_slen))
1447                                 continue;
1448                 }
1449                 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1450                         continue;
1451                 if (fi->fib_dead)
1452                         continue;
1453                 if (fa->fa_info->fib_scope < flp->flowi4_scope)
1454                         continue;
1455                 fib_alias_accessed(fa);
1456                 err = fib_props[fa->fa_type].error;
1457                 if (unlikely(err < 0)) {
1458 out_reject:
1459 #ifdef CONFIG_IP_FIB_TRIE_STATS
1460                         this_cpu_inc(stats->semantic_match_passed);
1461 #endif
1462                         trace_fib_table_lookup(tb->tb_id, flp, NULL, err);
1463                         return err;
1464                 }
1465                 if (fi->fib_flags & RTNH_F_DEAD)
1466                         continue;
1467 
1468                 if (unlikely(fi->nh && nexthop_is_blackhole(fi->nh))) {
1469                         err = fib_props[RTN_BLACKHOLE].error;
1470                         goto out_reject;
1471                 }
1472 
1473                 for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
1474                         struct fib_nh_common *nhc = fib_info_nhc(fi, nhsel);
1475 
1476                         if (nhc->nhc_flags & RTNH_F_DEAD)
1477                                 continue;
1478                         if (ip_ignore_linkdown(nhc->nhc_dev) &&
1479                             nhc->nhc_flags & RTNH_F_LINKDOWN &&
1480                             !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
1481                                 continue;
1482                         if (!(flp->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF)) {
1483                                 if (flp->flowi4_oif &&
1484                                     flp->flowi4_oif != nhc->nhc_oif)
1485                                         continue;
1486                         }
1487 
1488                         if (!(fib_flags & FIB_LOOKUP_NOREF))
1489                                 refcount_inc(&fi->fib_clntref);
1490 
1491                         res->prefix = htonl(n->key);
1492                         res->prefixlen = KEYLENGTH - fa->fa_slen;
1493                         res->nh_sel = nhsel;
1494                         res->nhc = nhc;
1495                         res->type = fa->fa_type;
1496                         res->scope = fi->fib_scope;
1497                         res->fi = fi;
1498                         res->table = tb;
1499                         res->fa_head = &n->leaf;
1500 #ifdef CONFIG_IP_FIB_TRIE_STATS
1501                         this_cpu_inc(stats->semantic_match_passed);
1502 #endif
1503                         trace_fib_table_lookup(tb->tb_id, flp, nhc, err);
1504 
1505                         return err;
1506                 }
1507         }
1508 #ifdef CONFIG_IP_FIB_TRIE_STATS
1509         this_cpu_inc(stats->semantic_match_miss);
1510 #endif
1511         goto backtrace;
1512 }
1513 EXPORT_SYMBOL_GPL(fib_table_lookup);
1514 
1515 static void fib_remove_alias(struct trie *t, struct key_vector *tp,
1516                              struct key_vector *l, struct fib_alias *old)
1517 {
1518         /* record the location of the previous list_info entry */
1519         struct hlist_node **pprev = old->fa_list.pprev;
1520         struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
1521 
1522         /* remove the fib_alias from the list */
1523         hlist_del_rcu(&old->fa_list);
1524 
1525         /* if we emptied the list this leaf will be freed and we can sort
1526          * out parent suffix lengths as a part of trie_rebalance
1527          */
1528         if (hlist_empty(&l->leaf)) {
1529                 if (tp->slen == l->slen)
1530                         node_pull_suffix(tp, tp->pos);
1531                 put_child_root(tp, l->key, NULL);
1532                 node_free(l);
1533                 trie_rebalance(t, tp);
1534                 return;
1535         }
1536 
1537         /* only access fa if it is pointing at the last valid hlist_node */
1538         if (*pprev)
1539                 return;
1540 
1541         /* update the trie with the latest suffix length */
1542         l->slen = fa->fa_slen;
1543         node_pull_suffix(tp, fa->fa_slen);
1544 }
1545 
1546 /* Caller must hold RTNL. */
1547 int fib_table_delete(struct net *net, struct fib_table *tb,
1548                      struct fib_config *cfg, struct netlink_ext_ack *extack)
1549 {
1550         struct trie *t = (struct trie *) tb->tb_data;
1551         struct fib_alias *fa, *fa_to_delete;
1552         struct key_vector *l, *tp;
1553         u8 plen = cfg->fc_dst_len;
1554         u8 slen = KEYLENGTH - plen;
1555         u8 tos = cfg->fc_tos;
1556         u32 key;
1557 
1558         key = ntohl(cfg->fc_dst);
1559 
1560         if (!fib_valid_key_len(key, plen, extack))
1561                 return -EINVAL;
1562 
1563         l = fib_find_node(t, &tp, key);
1564         if (!l)
1565                 return -ESRCH;
1566 
1567         fa = fib_find_alias(&l->leaf, slen, tos, 0, tb->tb_id);
1568         if (!fa)
1569                 return -ESRCH;
1570 
1571         pr_debug("Deleting %08x/%d tos=%d t=%p\n", key, plen, tos, t);
1572 
1573         fa_to_delete = NULL;
1574         hlist_for_each_entry_from(fa, fa_list) {
1575                 struct fib_info *fi = fa->fa_info;
1576 
1577                 if ((fa->fa_slen != slen) ||
1578                     (fa->tb_id != tb->tb_id) ||
1579                     (fa->fa_tos != tos))
1580                         break;
1581 
1582                 if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
1583                     (cfg->fc_scope == RT_SCOPE_NOWHERE ||
1584                      fa->fa_info->fib_scope == cfg->fc_scope) &&
1585                     (!cfg->fc_prefsrc ||
1586                      fi->fib_prefsrc == cfg->fc_prefsrc) &&
1587                     (!cfg->fc_protocol ||
1588                      fi->fib_protocol == cfg->fc_protocol) &&
1589                     fib_nh_match(cfg, fi, extack) == 0 &&
1590                     fib_metrics_match(cfg, fi)) {
1591                         fa_to_delete = fa;
1592                         break;
1593                 }
1594         }
1595 
1596         if (!fa_to_delete)
1597                 return -ESRCH;
1598 
1599         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key, plen,
1600                                  fa_to_delete, extack);
1601         rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
1602                   &cfg->fc_nlinfo, 0);
1603 
1604         if (!plen)
1605                 tb->tb_num_default--;
1606 
1607         fib_remove_alias(t, tp, l, fa_to_delete);
1608 
1609         if (fa_to_delete->fa_state & FA_S_ACCESSED)
1610                 rt_cache_flush(cfg->fc_nlinfo.nl_net);
1611 
1612         fib_release_info(fa_to_delete->fa_info);
1613         alias_free_mem_rcu(fa_to_delete);
1614         return 0;
1615 }
1616 
1617 /* Scan for the next leaf starting at the provided key value */
1618 static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
1619 {
1620         struct key_vector *pn, *n = *tn;
1621         unsigned long cindex;
1622 
1623         /* this loop is meant to try and find the key in the trie */
1624         do {
1625                 /* record parent and next child index */
1626                 pn = n;
1627                 cindex = (key > pn->key) ? get_index(key, pn) : 0;
1628 
1629                 if (cindex >> pn->bits)
1630                         break;
1631 
1632                 /* descend into the next child */
1633                 n = get_child_rcu(pn, cindex++);
1634                 if (!n)
1635                         break;
1636 
1637                 /* guarantee forward progress on the keys */
1638                 if (IS_LEAF(n) && (n->key >= key))
1639                         goto found;
1640         } while (IS_TNODE(n));
1641 
1642         /* this loop will search for the next leaf with a greater key */
1643         while (!IS_TRIE(pn)) {
1644                 /* if we exhausted the parent node we will need to climb */
1645                 if (cindex >= (1ul << pn->bits)) {
1646                         t_key pkey = pn->key;
1647 
1648                         pn = node_parent_rcu(pn);
1649                         cindex = get_index(pkey, pn) + 1;
1650                         continue;
1651                 }
1652 
1653                 /* grab the next available node */
1654                 n = get_child_rcu(pn, cindex++);
1655                 if (!n)
1656                         continue;
1657 
1658                 /* no need to compare keys since we bumped the index */
1659                 if (IS_LEAF(n))
1660                         goto found;
1661 
1662                 /* Rescan start scanning in new node */
1663                 pn = n;
1664                 cindex = 0;
1665         }
1666 
1667         *tn = pn;
1668         return NULL; /* Root of trie */
1669 found:
1670         /* if we are at the limit for keys just return NULL for the tnode */
1671         *tn = pn;
1672         return n;
1673 }
1674 
1675 static void fib_trie_free(struct fib_table *tb)
1676 {
1677         struct trie *t = (struct trie *)tb->tb_data;
1678         struct key_vector *pn = t->kv;
1679         unsigned long cindex = 1;
1680         struct hlist_node *tmp;
1681         struct fib_alias *fa;
1682 
1683         /* walk trie in reverse order and free everything */
1684         for (;;) {
1685                 struct key_vector *n;
1686 
1687                 if (!(cindex--)) {
1688                         t_key pkey = pn->key;
1689 
1690                         if (IS_TRIE(pn))
1691                                 break;
1692 
1693                         n = pn;
1694                         pn = node_parent(pn);
1695 
1696                         /* drop emptied tnode */
1697                         put_child_root(pn, n->key, NULL);
1698                         node_free(n);
1699 
1700                         cindex = get_index(pkey, pn);
1701 
1702                         continue;
1703                 }
1704 
1705                 /* grab the next available node */
1706                 n = get_child(pn, cindex);
1707                 if (!n)
1708                         continue;
1709 
1710                 if (IS_TNODE(n)) {
1711                         /* record pn and cindex for leaf walking */
1712                         pn = n;
1713                         cindex = 1ul << n->bits;
1714 
1715                         continue;
1716                 }
1717 
1718                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1719                         hlist_del_rcu(&fa->fa_list);
1720                         alias_free_mem_rcu(fa);
1721                 }
1722 
1723                 put_child_root(pn, n->key, NULL);
1724                 node_free(n);
1725         }
1726 
1727 #ifdef CONFIG_IP_FIB_TRIE_STATS
1728         free_percpu(t->stats);
1729 #endif
1730         kfree(tb);
1731 }
1732 
1733 struct fib_table *fib_trie_unmerge(struct fib_table *oldtb)
1734 {
1735         struct trie *ot = (struct trie *)oldtb->tb_data;
1736         struct key_vector *l, *tp = ot->kv;
1737         struct fib_table *local_tb;
1738         struct fib_alias *fa;
1739         struct trie *lt;
1740         t_key key = 0;
1741 
1742         if (oldtb->tb_data == oldtb->__data)
1743                 return oldtb;
1744 
1745         local_tb = fib_trie_table(RT_TABLE_LOCAL, NULL);
1746         if (!local_tb)
1747                 return NULL;
1748 
1749         lt = (struct trie *)local_tb->tb_data;
1750 
1751         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1752                 struct key_vector *local_l = NULL, *local_tp;
1753 
1754                 hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1755                         struct fib_alias *new_fa;
1756 
1757                         if (local_tb->tb_id != fa->tb_id)
1758                                 continue;
1759 
1760                         /* clone fa for new local table */
1761                         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1762                         if (!new_fa)
1763                                 goto out;
1764 
1765                         memcpy(new_fa, fa, sizeof(*fa));
1766 
1767                         /* insert clone into table */
1768                         if (!local_l)
1769                                 local_l = fib_find_node(lt, &local_tp, l->key);
1770 
1771                         if (fib_insert_alias(lt, local_tp, local_l, new_fa,
1772                                              NULL, l->key)) {
1773                                 kmem_cache_free(fn_alias_kmem, new_fa);
1774                                 goto out;
1775                         }
1776                 }
1777 
1778                 /* stop loop if key wrapped back to 0 */
1779                 key = l->key + 1;
1780                 if (key < l->key)
1781                         break;
1782         }
1783 
1784         return local_tb;
1785 out:
1786         fib_trie_free(local_tb);
1787 
1788         return NULL;
1789 }
1790 
1791 /* Caller must hold RTNL */
1792 void fib_table_flush_external(struct fib_table *tb)
1793 {
1794         struct trie *t = (struct trie *)tb->tb_data;
1795         struct key_vector *pn = t->kv;
1796         unsigned long cindex = 1;
1797         struct hlist_node *tmp;
1798         struct fib_alias *fa;
1799 
1800         /* walk trie in reverse order */
1801         for (;;) {
1802                 unsigned char slen = 0;
1803                 struct key_vector *n;
1804 
1805                 if (!(cindex--)) {
1806                         t_key pkey = pn->key;
1807 
1808                         /* cannot resize the trie vector */
1809                         if (IS_TRIE(pn))
1810                                 break;
1811 
1812                         /* update the suffix to address pulled leaves */
1813                         if (pn->slen > pn->pos)
1814                                 update_suffix(pn);
1815 
1816                         /* resize completed node */
1817                         pn = resize(t, pn);
1818                         cindex = get_index(pkey, pn);
1819 
1820                         continue;
1821                 }
1822 
1823                 /* grab the next available node */
1824                 n = get_child(pn, cindex);
1825                 if (!n)
1826                         continue;
1827 
1828                 if (IS_TNODE(n)) {
1829                         /* record pn and cindex for leaf walking */
1830                         pn = n;
1831                         cindex = 1ul << n->bits;
1832 
1833                         continue;
1834                 }
1835 
1836                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1837                         /* if alias was cloned to local then we just
1838                          * need to remove the local copy from main
1839                          */
1840                         if (tb->tb_id != fa->tb_id) {
1841                                 hlist_del_rcu(&fa->fa_list);
1842                                 alias_free_mem_rcu(fa);
1843                                 continue;
1844                         }
1845 
1846                         /* record local slen */
1847                         slen = fa->fa_slen;
1848                 }
1849 
1850                 /* update leaf slen */
1851                 n->slen = slen;
1852 
1853                 if (hlist_empty(&n->leaf)) {
1854                         put_child_root(pn, n->key, NULL);
1855                         node_free(n);
1856                 }
1857         }
1858 }
1859 
1860 /* Caller must hold RTNL. */
1861 int fib_table_flush(struct net *net, struct fib_table *tb, bool flush_all)
1862 {
1863         struct trie *t = (struct trie *)tb->tb_data;
1864         struct key_vector *pn = t->kv;
1865         unsigned long cindex = 1;
1866         struct hlist_node *tmp;
1867         struct fib_alias *fa;
1868         int found = 0;
1869 
1870         /* walk trie in reverse order */
1871         for (;;) {
1872                 unsigned char slen = 0;
1873                 struct key_vector *n;
1874 
1875                 if (!(cindex--)) {
1876                         t_key pkey = pn->key;
1877 
1878                         /* cannot resize the trie vector */
1879                         if (IS_TRIE(pn))
1880                                 break;
1881 
1882                         /* update the suffix to address pulled leaves */
1883                         if (pn->slen > pn->pos)
1884                                 update_suffix(pn);
1885 
1886                         /* resize completed node */
1887                         pn = resize(t, pn);
1888                         cindex = get_index(pkey, pn);
1889 
1890                         continue;
1891                 }
1892 
1893                 /* grab the next available node */
1894                 n = get_child(pn, cindex);
1895                 if (!n)
1896                         continue;
1897 
1898                 if (IS_TNODE(n)) {
1899                         /* record pn and cindex for leaf walking */
1900                         pn = n;
1901                         cindex = 1ul << n->bits;
1902 
1903                         continue;
1904                 }
1905 
1906                 hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1907                         struct fib_info *fi = fa->fa_info;
1908 
1909                         if (!fi || tb->tb_id != fa->tb_id ||
1910                             (!(fi->fib_flags & RTNH_F_DEAD) &&
1911                              !fib_props[fa->fa_type].error)) {
1912                                 slen = fa->fa_slen;
1913                                 continue;
1914                         }
1915 
1916                         /* Do not flush error routes if network namespace is
1917                          * not being dismantled
1918                          */
1919                         if (!flush_all && fib_props[fa->fa_type].error) {
1920                                 slen = fa->fa_slen;
1921                                 continue;
1922                         }
1923 
1924                         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
1925                                                  n->key,
1926                                                  KEYLENGTH - fa->fa_slen, fa,
1927                                                  NULL);
1928                         hlist_del_rcu(&fa->fa_list);
1929                         fib_release_info(fa->fa_info);
1930                         alias_free_mem_rcu(fa);
1931                         found++;
1932                 }
1933 
1934                 /* update leaf slen */
1935                 n->slen = slen;
1936 
1937                 if (hlist_empty(&n->leaf)) {
1938                         put_child_root(pn, n->key, NULL);
1939                         node_free(n);
1940                 }
1941         }
1942 
1943         pr_debug("trie_flush found=%d\n", found);
1944         return found;
1945 }
1946 
1947 /* derived from fib_trie_free */
1948 static void __fib_info_notify_update(struct net *net, struct fib_table *tb,
1949                                      struct nl_info *info)
1950 {
1951         struct trie *t = (struct trie *)tb->tb_data;
1952         struct key_vector *pn = t->kv;
1953         unsigned long cindex = 1;
1954         struct fib_alias *fa;
1955 
1956         for (;;) {
1957                 struct key_vector *n;
1958 
1959                 if (!(cindex--)) {
1960                         t_key pkey = pn->key;
1961 
1962                         if (IS_TRIE(pn))
1963                                 break;
1964 
1965                         pn = node_parent(pn);
1966                         cindex = get_index(pkey, pn);
1967                         continue;
1968                 }
1969 
1970                 /* grab the next available node */
1971                 n = get_child(pn, cindex);
1972                 if (!n)
1973                         continue;
1974 
1975                 if (IS_TNODE(n)) {
1976                         /* record pn and cindex for leaf walking */
1977                         pn = n;
1978                         cindex = 1ul << n->bits;
1979 
1980                         continue;
1981                 }
1982 
1983                 hlist_for_each_entry(fa, &n->leaf, fa_list) {
1984                         struct fib_info *fi = fa->fa_info;
1985 
1986                         if (!fi || !fi->nh_updated || fa->tb_id != tb->tb_id)
1987                                 continue;
1988 
1989                         rtmsg_fib(RTM_NEWROUTE, htonl(n->key), fa,
1990                                   KEYLENGTH - fa->fa_slen, tb->tb_id,
1991                                   info, NLM_F_REPLACE);
1992 
1993                         /* call_fib_entry_notifiers will be removed when
1994                          * in-kernel notifier is implemented and supported
1995                          * for nexthop objects
1996                          */
1997                         call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_REPLACE,
1998                                                  n->key,
1999                                                  KEYLENGTH - fa->fa_slen, fa,
2000                                                  NULL);
2001                 }
2002         }
2003 }
2004 
2005 void fib_info_notify_update(struct net *net, struct nl_info *info)
2006 {
2007         unsigned int h;
2008 
2009         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2010                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2011                 struct fib_table *tb;
2012 
2013                 hlist_for_each_entry_rcu(tb, head, tb_hlist)
2014                         __fib_info_notify_update(net, tb, info);
2015         }
2016 }
2017 
2018 static void fib_leaf_notify(struct net *net, struct key_vector *l,
2019                             struct fib_table *tb, struct notifier_block *nb)
2020 {
2021         struct fib_alias *fa;
2022 
2023         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2024                 struct fib_info *fi = fa->fa_info;
2025 
2026                 if (!fi)
2027                         continue;
2028 
2029                 /* local and main table can share the same trie,
2030                  * so don't notify twice for the same entry.
2031                  */
2032                 if (tb->tb_id != fa->tb_id)
2033                         continue;
2034 
2035                 call_fib_entry_notifier(nb, net, FIB_EVENT_ENTRY_ADD, l->key,
2036                                         KEYLENGTH - fa->fa_slen, fa);
2037         }
2038 }
2039 
2040 static void fib_table_notify(struct net *net, struct fib_table *tb,
2041                              struct notifier_block *nb)
2042 {
2043         struct trie *t = (struct trie *)tb->tb_data;
2044         struct key_vector *l, *tp = t->kv;
2045         t_key key = 0;
2046 
2047         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
2048                 fib_leaf_notify(net, l, tb, nb);
2049 
2050                 key = l->key + 1;
2051                 /* stop in case of wrap around */
2052                 if (key < l->key)
2053                         break;
2054         }
2055 }
2056 
2057 void fib_notify(struct net *net, struct notifier_block *nb)
2058 {
2059         unsigned int h;
2060 
2061         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2062                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2063                 struct fib_table *tb;
2064 
2065                 hlist_for_each_entry_rcu(tb, head, tb_hlist)
2066                         fib_table_notify(net, tb, nb);
2067         }
2068 }
2069 
2070 static void __trie_free_rcu(struct rcu_head *head)
2071 {
2072         struct fib_table *tb = container_of(head, struct fib_table, rcu);
2073 #ifdef CONFIG_IP_FIB_TRIE_STATS
2074         struct trie *t = (struct trie *)tb->tb_data;
2075 
2076         if (tb->tb_data == tb->__data)
2077                 free_percpu(t->stats);
2078 #endif /* CONFIG_IP_FIB_TRIE_STATS */
2079         kfree(tb);
2080 }
2081 
2082 void fib_free_table(struct fib_table *tb)
2083 {
2084         call_rcu(&tb->rcu, __trie_free_rcu);
2085 }
2086 
2087 static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
2088                              struct sk_buff *skb, struct netlink_callback *cb,
2089                              struct fib_dump_filter *filter)
2090 {
2091         unsigned int flags = NLM_F_MULTI;
2092         __be32 xkey = htonl(l->key);
2093         int i, s_i, i_fa, s_fa, err;
2094         struct fib_alias *fa;
2095 
2096         if (filter->filter_set ||
2097             !filter->dump_exceptions || !filter->dump_routes)
2098                 flags |= NLM_F_DUMP_FILTERED;
2099 
2100         s_i = cb->args[4];
2101         s_fa = cb->args[5];
2102         i = 0;
2103 
2104         /* rcu_read_lock is hold by caller */
2105         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2106                 struct fib_info *fi = fa->fa_info;
2107 
2108                 if (i < s_i)
2109                         goto next;
2110 
2111                 i_fa = 0;
2112 
2113                 if (tb->tb_id != fa->tb_id)
2114                         goto next;
2115 
2116                 if (filter->filter_set) {
2117                         if (filter->rt_type && fa->fa_type != filter->rt_type)
2118                                 goto next;
2119 
2120                         if ((filter->protocol &&
2121                              fi->fib_protocol != filter->protocol))
2122                                 goto next;
2123 
2124                         if (filter->dev &&
2125                             !fib_info_nh_uses_dev(fi, filter->dev))
2126                                 goto next;
2127                 }
2128 
2129                 if (filter->dump_routes) {
2130                         if (!s_fa) {
2131                                 err = fib_dump_info(skb,
2132                                                     NETLINK_CB(cb->skb).portid,
2133                                                     cb->nlh->nlmsg_seq,
2134                                                     RTM_NEWROUTE,
2135                                                     tb->tb_id, fa->fa_type,
2136                                                     xkey,
2137                                                     KEYLENGTH - fa->fa_slen,
2138                                                     fa->fa_tos, fi, flags);
2139                                 if (err < 0)
2140                                         goto stop;
2141                         }
2142 
2143                         i_fa++;
2144                 }
2145 
2146                 if (filter->dump_exceptions) {
2147                         err = fib_dump_info_fnhe(skb, cb, tb->tb_id, fi,
2148                                                  &i_fa, s_fa, flags);
2149                         if (err < 0)
2150                                 goto stop;
2151                 }
2152 
2153 next:
2154                 i++;
2155         }
2156 
2157         cb->args[4] = i;
2158         return skb->len;
2159 
2160 stop:
2161         cb->args[4] = i;
2162         cb->args[5] = i_fa;
2163         return err;
2164 }
2165 
2166 /* rcu_read_lock needs to be hold by caller from readside */
2167 int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
2168                    struct netlink_callback *cb, struct fib_dump_filter *filter)
2169 {
2170         struct trie *t = (struct trie *)tb->tb_data;
2171         struct key_vector *l, *tp = t->kv;
2172         /* Dump starting at last key.
2173          * Note: 0.0.0.0/0 (ie default) is first key.
2174          */
2175         int count = cb->args[2];
2176         t_key key = cb->args[3];
2177 
2178         /* First time here, count and key are both always 0. Count > 0
2179          * and key == 0 means the dump has wrapped around and we are done.
2180          */
2181         if (count && !key)
2182                 return skb->len;
2183 
2184         while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
2185                 int err;
2186 
2187                 err = fn_trie_dump_leaf(l, tb, skb, cb, filter);
2188                 if (err < 0) {
2189                         cb->args[3] = key;
2190                         cb->args[2] = count;
2191                         return err;
2192                 }
2193 
2194                 ++count;
2195                 key = l->key + 1;
2196 
2197                 memset(&cb->args[4], 0,
2198                        sizeof(cb->args) - 4*sizeof(cb->args[0]));
2199 
2200                 /* stop loop if key wrapped back to 0 */
2201                 if (key < l->key)
2202                         break;
2203         }
2204 
2205         cb->args[3] = key;
2206         cb->args[2] = count;
2207 
2208         return skb->len;
2209 }
2210 
2211 void __init fib_trie_init(void)
2212 {
2213         fn_alias_kmem = kmem_cache_create("ip_fib_alias",
2214                                           sizeof(struct fib_alias),
2215                                           0, SLAB_PANIC, NULL);
2216 
2217         trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
2218                                            LEAF_SIZE,
2219                                            0, SLAB_PANIC, NULL);
2220 }
2221 
2222 struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
2223 {
2224         struct fib_table *tb;
2225         struct trie *t;
2226         size_t sz = sizeof(*tb);
2227 
2228         if (!alias)
2229                 sz += sizeof(struct trie);
2230 
2231         tb = kzalloc(sz, GFP_KERNEL);
2232         if (!tb)
2233                 return NULL;
2234 
2235         tb->tb_id = id;
2236         tb->tb_num_default = 0;
2237         tb->tb_data = (alias ? alias->__data : tb->__data);
2238 
2239         if (alias)
2240                 return tb;
2241 
2242         t = (struct trie *) tb->tb_data;
2243         t->kv[0].pos = KEYLENGTH;
2244         t->kv[0].slen = KEYLENGTH;
2245 #ifdef CONFIG_IP_FIB_TRIE_STATS
2246         t->stats = alloc_percpu(struct trie_use_stats);
2247         if (!t->stats) {
2248                 kfree(tb);
2249                 tb = NULL;
2250         }
2251 #endif
2252 
2253         return tb;
2254 }
2255 
2256 #ifdef CONFIG_PROC_FS
2257 /* Depth first Trie walk iterator */
2258 struct fib_trie_iter {
2259         struct seq_net_private p;
2260         struct fib_table *tb;
2261         struct key_vector *tnode;
2262         unsigned int index;
2263         unsigned int depth;
2264 };
2265 
2266 static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
2267 {
2268         unsigned long cindex = iter->index;
2269         struct key_vector *pn = iter->tnode;
2270         t_key pkey;
2271 
2272         pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
2273                  iter->tnode, iter->index, iter->depth);
2274 
2275         while (!IS_TRIE(pn)) {
2276                 while (cindex < child_length(pn)) {
2277                         struct key_vector *n = get_child_rcu(pn, cindex++);
2278 
2279                         if (!n)
2280                                 continue;
2281 
2282                         if (IS_LEAF(n)) {
2283                                 iter->tnode = pn;
2284                                 iter->index = cindex;
2285                         } else {
2286                                 /* push down one level */
2287                                 iter->tnode = n;
2288                                 iter->index = 0;
2289                                 ++iter->depth;
2290                         }
2291 
2292                         return n;
2293                 }
2294 
2295                 /* Current node exhausted, pop back up */
2296                 pkey = pn->key;
2297                 pn = node_parent_rcu(pn);
2298                 cindex = get_index(pkey, pn) + 1;
2299                 --iter->depth;
2300         }
2301 
2302         /* record root node so further searches know we are done */
2303         iter->tnode = pn;
2304         iter->index = 0;
2305 
2306         return NULL;
2307 }
2308 
2309 static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
2310                                              struct trie *t)
2311 {
2312         struct key_vector *n, *pn;
2313 
2314         if (!t)
2315                 return NULL;
2316 
2317         pn = t->kv;
2318         n = rcu_dereference(pn->tnode[0]);
2319         if (!n)
2320                 return NULL;
2321 
2322         if (IS_TNODE(n)) {
2323                 iter->tnode = n;
2324                 iter->index = 0;
2325                 iter->depth = 1;
2326         } else {
2327                 iter->tnode = pn;
2328                 iter->index = 0;
2329                 iter->depth = 0;
2330         }
2331 
2332         return n;
2333 }
2334 
2335 static void trie_collect_stats(struct trie *t, struct trie_stat *s)
2336 {
2337         struct key_vector *n;
2338         struct fib_trie_iter iter;
2339 
2340         memset(s, 0, sizeof(*s));
2341 
2342         rcu_read_lock();
2343         for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
2344                 if (IS_LEAF(n)) {
2345                         struct fib_alias *fa;
2346 
2347                         s->leaves++;
2348                         s->totdepth += iter.depth;
2349                         if (iter.depth > s->maxdepth)
2350                                 s->maxdepth = iter.depth;
2351 
2352                         hlist_for_each_entry_rcu(fa, &n->leaf, fa_list)
2353                                 ++s->prefixes;
2354                 } else {
2355                         s->tnodes++;
2356                         if (n->bits < MAX_STAT_DEPTH)
2357                                 s->nodesizes[n->bits]++;
2358                         s->nullpointers += tn_info(n)->empty_children;
2359                 }
2360         }
2361         rcu_read_unlock();
2362 }
2363 
2364 /*
2365  *      This outputs /proc/net/fib_triestats
2366  */
2367 static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
2368 {
2369         unsigned int i, max, pointers, bytes, avdepth;
2370 
2371         if (stat->leaves)
2372                 avdepth = stat->totdepth*100 / stat->leaves;
2373         else
2374                 avdepth = 0;
2375 
2376         seq_printf(seq, "\tAver depth:     %u.%02d\n",
2377                    avdepth / 100, avdepth % 100);
2378         seq_printf(seq, "\tMax depth:      %u\n", stat->maxdepth);
2379 
2380         seq_printf(seq, "\tLeaves:         %u\n", stat->leaves);
2381         bytes = LEAF_SIZE * stat->leaves;
2382 
2383         seq_printf(seq, "\tPrefixes:       %u\n", stat->prefixes);
2384         bytes += sizeof(struct fib_alias) * stat->prefixes;
2385 
2386         seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
2387         bytes += TNODE_SIZE(0) * stat->tnodes;
2388 
2389         max = MAX_STAT_DEPTH;
2390         while (max > 0 && stat->nodesizes[max-1] == 0)
2391                 max--;
2392 
2393         pointers = 0;
2394         for (i = 1; i < max; i++)
2395                 if (stat->nodesizes[i] != 0) {
2396                         seq_printf(seq, "  %u: %u",  i, stat->nodesizes[i]);
2397                         pointers += (1<<i) * stat->nodesizes[i];
2398                 }
2399         seq_putc(seq, '\n');
2400         seq_printf(seq, "\tPointers: %u\n", pointers);
2401 
2402         bytes += sizeof(struct key_vector *) * pointers;
2403         seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
2404         seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
2405 }
2406 
2407 #ifdef CONFIG_IP_FIB_TRIE_STATS
2408 static void trie_show_usage(struct seq_file *seq,
2409                             const struct trie_use_stats __percpu *stats)
2410 {
2411         struct trie_use_stats s = { 0 };
2412         int cpu;
2413 
2414         /* loop through all of the CPUs and gather up the stats */
2415         for_each_possible_cpu(cpu) {
2416                 const struct trie_use_stats *pcpu = per_cpu_ptr(stats, cpu);
2417 
2418                 s.gets += pcpu->gets;
2419                 s.backtrack += pcpu->backtrack;
2420                 s.semantic_match_passed += pcpu->semantic_match_passed;
2421                 s.semantic_match_miss += pcpu->semantic_match_miss;
2422                 s.null_node_hit += pcpu->null_node_hit;
2423                 s.resize_node_skipped += pcpu->resize_node_skipped;
2424         }
2425 
2426         seq_printf(seq, "\nCounters:\n---------\n");
2427         seq_printf(seq, "gets = %u\n", s.gets);
2428         seq_printf(seq, "backtracks = %u\n", s.backtrack);
2429         seq_printf(seq, "semantic match passed = %u\n",
2430                    s.semantic_match_passed);
2431         seq_printf(seq, "semantic match miss = %u\n", s.semantic_match_miss);
2432         seq_printf(seq, "null node hit= %u\n", s.null_node_hit);
2433         seq_printf(seq, "skipped node resize = %u\n\n", s.resize_node_skipped);
2434 }
2435 #endif /*  CONFIG_IP_FIB_TRIE_STATS */
2436 
2437 static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
2438 {
2439         if (tb->tb_id == RT_TABLE_LOCAL)
2440                 seq_puts(seq, "Local:\n");
2441         else if (tb->tb_id == RT_TABLE_MAIN)
2442                 seq_puts(seq, "Main:\n");
2443         else
2444                 seq_printf(seq, "Id %d:\n", tb->tb_id);
2445 }
2446 
2447 
2448 static int fib_triestat_seq_show(struct seq_file *seq, void *v)
2449 {
2450         struct net *net = (struct net *)seq->private;
2451         unsigned int h;
2452 
2453         seq_printf(seq,
2454                    "Basic info: size of leaf:"
2455                    " %zd bytes, size of tnode: %zd bytes.\n",
2456                    LEAF_SIZE, TNODE_SIZE(0));
2457 
2458         rcu_read_lock();
2459         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2460                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2461                 struct fib_table *tb;
2462 
2463                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2464                         struct trie *t = (struct trie *) tb->tb_data;
2465                         struct trie_stat stat;
2466 
2467                         if (!t)
2468                                 continue;
2469 
2470                         fib_table_print(seq, tb);
2471 
2472                         trie_collect_stats(t, &stat);
2473                         trie_show_stats(seq, &stat);
2474 #ifdef CONFIG_IP_FIB_TRIE_STATS
2475                         trie_show_usage(seq, t->stats);
2476 #endif
2477                 }
2478                 cond_resched_rcu();
2479         }
2480         rcu_read_unlock();
2481 
2482         return 0;
2483 }
2484 
2485 static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
2486 {
2487         struct fib_trie_iter *iter = seq->private;
2488         struct net *net = seq_file_net(seq);
2489         loff_t idx = 0;
2490         unsigned int h;
2491 
2492         for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2493                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2494                 struct fib_table *tb;
2495 
2496                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2497                         struct key_vector *n;
2498 
2499                         for (n = fib_trie_get_first(iter,
2500                                                     (struct trie *) tb->tb_data);
2501                              n; n = fib_trie_get_next(iter))
2502                                 if (pos == idx++) {
2503                                         iter->tb = tb;
2504                                         return n;
2505                                 }
2506                 }
2507         }
2508 
2509         return NULL;
2510 }
2511 
2512 static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
2513         __acquires(RCU)
2514 {
2515         rcu_read_lock();
2516         return fib_trie_get_idx(seq, *pos);
2517 }
2518 
2519 static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2520 {
2521         struct fib_trie_iter *iter = seq->private;
2522         struct net *net = seq_file_net(seq);
2523         struct fib_table *tb = iter->tb;
2524         struct hlist_node *tb_node;
2525         unsigned int h;
2526         struct key_vector *n;
2527 
2528         ++*pos;
2529         /* next node in same table */
2530         n = fib_trie_get_next(iter);
2531         if (n)
2532                 return n;
2533 
2534         /* walk rest of this hash chain */
2535         h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
2536         while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
2537                 tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
2538                 n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2539                 if (n)
2540                         goto found;
2541         }
2542 
2543         /* new hash chain */
2544         while (++h < FIB_TABLE_HASHSZ) {
2545                 struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2546                 hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2547                         n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2548                         if (n)
2549                                 goto found;
2550                 }
2551         }
2552         return NULL;
2553 
2554 found:
2555         iter->tb = tb;
2556         return n;
2557 }
2558 
2559 static void fib_trie_seq_stop(struct seq_file *seq, void *v)
2560         __releases(RCU)
2561 {
2562         rcu_read_unlock();
2563 }
2564 
2565 static void seq_indent(struct seq_file *seq, int n)
2566 {
2567         while (n-- > 0)
2568                 seq_puts(seq, "   ");
2569 }
2570 
2571 static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
2572 {
2573         switch (s) {
2574         case RT_SCOPE_UNIVERSE: return "universe";
2575         case RT_SCOPE_SITE:     return "site";
2576         case RT_SCOPE_LINK:     return "link";
2577         case RT_SCOPE_HOST:     return "host";
2578         case RT_SCOPE_NOWHERE:  return "nowhere";
2579         default:
2580                 snprintf(buf, len, "scope=%d", s);
2581                 return buf;
2582         }
2583 }
2584 
2585 static const char *const rtn_type_names[__RTN_MAX] = {
2586         [RTN_UNSPEC] = "UNSPEC",
2587         [RTN_UNICAST] = "UNICAST",
2588         [RTN_LOCAL] = "LOCAL",
2589         [RTN_BROADCAST] = "BROADCAST",
2590         [RTN_ANYCAST] = "ANYCAST",
2591         [RTN_MULTICAST] = "MULTICAST",
2592         [RTN_BLACKHOLE] = "BLACKHOLE",
2593         [RTN_UNREACHABLE] = "UNREACHABLE",
2594         [RTN_PROHIBIT] = "PROHIBIT",
2595         [RTN_THROW] = "THROW",
2596         [RTN_NAT] = "NAT",
2597         [RTN_XRESOLVE] = "XRESOLVE",
2598 };
2599 
2600 static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
2601 {
2602         if (t < __RTN_MAX && rtn_type_names[t])
2603                 return rtn_type_names[t];
2604         snprintf(buf, len, "type %u", t);
2605         return buf;
2606 }
2607 
2608 /* Pretty print the trie */
2609 static int fib_trie_seq_show(struct seq_file *seq, void *v)
2610 {
2611         const struct fib_trie_iter *iter = seq->private;
2612         struct key_vector *n = v;
2613 
2614         if (IS_TRIE(node_parent_rcu(n)))
2615                 fib_table_print(seq, iter->tb);
2616 
2617         if (IS_TNODE(n)) {
2618                 __be32 prf = htonl(n->key);
2619 
2620                 seq_indent(seq, iter->depth-1);
2621                 seq_printf(seq, "  +-- %pI4/%zu %u %u %u\n",
2622                            &prf, KEYLENGTH - n->pos - n->bits, n->bits,
2623                            tn_info(n)->full_children,
2624                            tn_info(n)->empty_children);
2625         } else {
2626                 __be32 val = htonl(n->key);
2627                 struct fib_alias *fa;
2628 
2629                 seq_indent(seq, iter->depth);
2630                 seq_printf(seq, "  |-- %pI4\n", &val);
2631 
2632                 hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
2633                         char buf1[32], buf2[32];
2634 
2635                         seq_indent(seq, iter->depth + 1);
2636                         seq_printf(seq, "  /%zu %s %s",
2637                                    KEYLENGTH - fa->fa_slen,
2638                                    rtn_scope(buf1, sizeof(buf1),
2639                                              fa->fa_info->fib_scope),
2640                                    rtn_type(buf2, sizeof(buf2),
2641                                             fa->fa_type));
2642                         if (fa->fa_tos)
2643                                 seq_printf(seq, " tos=%d", fa->fa_tos);
2644                         seq_putc(seq, '\n');
2645                 }
2646         }
2647 
2648         return 0;
2649 }
2650 
2651 static const struct seq_operations fib_trie_seq_ops = {
2652         .start  = fib_trie_seq_start,
2653         .next   = fib_trie_seq_next,
2654         .stop   = fib_trie_seq_stop,
2655         .show   = fib_trie_seq_show,
2656 };
2657 
2658 struct fib_route_iter {
2659         struct seq_net_private p;
2660         struct fib_table *main_tb;
2661         struct key_vector *tnode;
2662         loff_t  pos;
2663         t_key   key;
2664 };
2665 
2666 static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
2667                                             loff_t pos)
2668 {
2669         struct key_vector *l, **tp = &iter->tnode;
2670         t_key key;
2671 
2672         /* use cached location of previously found key */
2673         if (iter->pos > 0 && pos >= iter->pos) {
2674                 key = iter->key;
2675         } else {
2676                 iter->pos = 1;
2677                 key = 0;
2678         }
2679 
2680         pos -= iter->pos;
2681 
2682         while ((l = leaf_walk_rcu(tp, key)) && (pos-- > 0)) {
2683                 key = l->key + 1;
2684                 iter->pos++;
2685                 l = NULL;
2686 
2687                 /* handle unlikely case of a key wrap */
2688                 if (!key)
2689                         break;
2690         }
2691 
2692         if (l)
2693                 iter->key = l->key;     /* remember it */
2694         else
2695                 iter->pos = 0;          /* forget it */
2696 
2697         return l;
2698 }
2699 
2700 static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
2701         __acquires(RCU)
2702 {
2703         struct fib_route_iter *iter = seq->private;
2704         struct fib_table *tb;
2705         struct trie *t;
2706 
2707         rcu_read_lock();
2708 
2709         tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
2710         if (!tb)
2711                 return NULL;
2712 
2713         iter->main_tb = tb;
2714         t = (struct trie *)tb->tb_data;
2715         iter->tnode = t->kv;
2716 
2717         if (*pos != 0)
2718                 return fib_route_get_idx(iter, *pos);
2719 
2720         iter->pos = 0;
2721         iter->key = KEY_MAX;
2722 
2723         return SEQ_START_TOKEN;
2724 }
2725 
2726 static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2727 {
2728         struct fib_route_iter *iter = seq->private;
2729         struct key_vector *l = NULL;
2730         t_key key = iter->key + 1;
2731 
2732         ++*pos;
2733 
2734         /* only allow key of 0 for start of sequence */
2735         if ((v == SEQ_START_TOKEN) || key)
2736                 l = leaf_walk_rcu(&iter->tnode, key);
2737 
2738         if (l) {
2739                 iter->key = l->key;
2740                 iter->pos++;
2741         } else {
2742                 iter->pos = 0;
2743         }
2744 
2745         return l;
2746 }
2747 
2748 static void fib_route_seq_stop(struct seq_file *seq, void *v)
2749         __releases(RCU)
2750 {
2751         rcu_read_unlock();
2752 }
2753 
2754 static unsigned int fib_flag_trans(int type, __be32 mask, struct fib_info *fi)
2755 {
2756         unsigned int flags = 0;
2757 
2758         if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
2759                 flags = RTF_REJECT;
2760         if (fi) {
2761                 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
2762 
2763                 if (nhc->nhc_gw.ipv4)
2764                         flags |= RTF_GATEWAY;
2765         }
2766         if (mask == htonl(0xFFFFFFFF))
2767                 flags |= RTF_HOST;
2768         flags |= RTF_UP;
2769         return flags;
2770 }
2771 
2772 /*
2773  *      This outputs /proc/net/route.
2774  *      The format of the file is not supposed to be changed
2775  *      and needs to be same as fib_hash output to avoid breaking
2776  *      legacy utilities
2777  */
2778 static int fib_route_seq_show(struct seq_file *seq, void *v)
2779 {
2780         struct fib_route_iter *iter = seq->private;
2781         struct fib_table *tb = iter->main_tb;
2782         struct fib_alias *fa;
2783         struct key_vector *l = v;
2784         __be32 prefix;
2785 
2786         if (v == SEQ_START_TOKEN) {
2787                 seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
2788                            "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
2789                            "\tWindow\tIRTT");
2790                 return 0;
2791         }
2792 
2793         prefix = htonl(l->key);
2794 
2795         hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2796                 struct fib_info *fi = fa->fa_info;
2797                 __be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
2798                 unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
2799 
2800                 if ((fa->fa_type == RTN_BROADCAST) ||
2801                     (fa->fa_type == RTN_MULTICAST))
2802                         continue;
2803 
2804                 if (fa->tb_id != tb->tb_id)
2805                         continue;
2806 
2807                 seq_setwidth(seq, 127);
2808 
2809                 if (fi) {
2810                         struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
2811                         __be32 gw = 0;
2812 
2813                         if (nhc->nhc_gw_family == AF_INET)
2814                                 gw = nhc->nhc_gw.ipv4;
2815 
2816                         seq_printf(seq,
2817                                    "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
2818                                    "%d\t%08X\t%d\t%u\t%u",
2819                                    nhc->nhc_dev ? nhc->nhc_dev->name : "*",
2820                                    prefix, gw, flags, 0, 0,
2821                                    fi->fib_priority,
2822                                    mask,
2823                                    (fi->fib_advmss ?
2824                                     fi->fib_advmss + 40 : 0),
2825                                    fi->fib_window,
2826                                    fi->fib_rtt >> 3);
2827                 } else {
2828                         seq_printf(seq,
2829                                    "*\t%08X\t%08X\t%04X\t%d\t%u\t"
2830                                    "%d\t%08X\t%d\t%u\t%u",
2831                                    prefix, 0, flags, 0, 0, 0,
2832                                    mask, 0, 0, 0);
2833                 }
2834                 seq_pad(seq, '\n');
2835         }
2836 
2837         return 0;
2838 }
2839 
2840 static const struct seq_operations fib_route_seq_ops = {
2841         .start  = fib_route_seq_start,
2842         .next   = fib_route_seq_next,
2843         .stop   = fib_route_seq_stop,
2844         .show   = fib_route_seq_show,
2845 };
2846 
2847 int __net_init fib_proc_init(struct net *net)
2848 {
2849         if (!proc_create_net("fib_trie", 0444, net->proc_net, &fib_trie_seq_ops,
2850                         sizeof(struct fib_trie_iter)))
2851                 goto out1;
2852 
2853         if (!proc_create_net_single("fib_triestat", 0444, net->proc_net,
2854                         fib_triestat_seq_show, NULL))
2855                 goto out2;
2856 
2857         if (!proc_create_net("route", 0444, net->proc_net, &fib_route_seq_ops,
2858                         sizeof(struct fib_route_iter)))
2859                 goto out3;
2860 
2861         return 0;
2862 
2863 out3:
2864         remove_proc_entry("fib_triestat", net->proc_net);
2865 out2:
2866         remove_proc_entry("fib_trie", net->proc_net);
2867 out1:
2868         return -ENOMEM;
2869 }
2870 
2871 void __net_exit fib_proc_exit(struct net *net)
2872 {
2873         remove_proc_entry("fib_trie", net->proc_net);
2874         remove_proc_entry("fib_triestat", net->proc_net);
2875         remove_proc_entry("route", net->proc_net);
2876 }
2877 
2878 #endif /* CONFIG_PROC_FS */