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Committer: Michael Beasley <mike@snafu.setup>
[mikesnafu-overlay.git] / net / ipv6 / ip6_fib.c
blobbab72b6f14444f9701d830ff6d93f009bb753926
1 /*
2 * Linux INET6 implementation
3 * Forwarding Information Database
4 *
5 * Authors:
6 * Pedro Roque <roque@di.fc.ul.pt>
7 *
8 * $Id: ip6_fib.c,v 1.25 2001/10/31 21:55:55 davem Exp $
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16 /*
17 * Changes:
18 * Yuji SEKIYA @USAGI: Support default route on router node;
19 * remove ip6_null_entry from the top of
20 * routing table.
21 * Ville Nuorvala: Fixed routing subtrees.
22 */
23 #include <linux/errno.h>
24 #include <linux/types.h>
25 #include <linux/net.h>
26 #include <linux/route.h>
27 #include <linux/netdevice.h>
28 #include <linux/in6.h>
29 #include <linux/init.h>
30 #include <linux/list.h>
31
32 #ifdef CONFIG_PROC_FS
33 #include <linux/proc_fs.h>
34 #endif
35
36 #include <net/ipv6.h>
37 #include <net/ndisc.h>
38 #include <net/addrconf.h>
39
40 #include <net/ip6_fib.h>
41 #include <net/ip6_route.h>
42
43 #define RT6_DEBUG 2
44
45 #if RT6_DEBUG >= 3
46 #define RT6_TRACE(x...) printk(KERN_DEBUG x)
47 #else
48 #define RT6_TRACE(x...) do { ; } while (0)
49 #endif
50
51 struct rt6_statistics rt6_stats;
52
53 static struct kmem_cache * fib6_node_kmem __read_mostly;
54
55 enum fib_walk_state_t
56 {
57 #ifdef CONFIG_IPV6_SUBTREES
58 FWS_S,
59 #endif
60 FWS_L,
61 FWS_R,
62 FWS_C,
63 FWS_U
64 };
65
66 struct fib6_cleaner_t
67 {
68 struct fib6_walker_t w;
69 int (*func)(struct rt6_info *, void *arg);
70 void *arg;
71 };
72
73 static DEFINE_RWLOCK(fib6_walker_lock);
74
75 #ifdef CONFIG_IPV6_SUBTREES
76 #define FWS_INIT FWS_S
77 #else
78 #define FWS_INIT FWS_L
79 #endif
80
81 static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt);
82 static struct rt6_info * fib6_find_prefix(struct fib6_node *fn);
83 static struct fib6_node * fib6_repair_tree(struct fib6_node *fn);
84 static int fib6_walk(struct fib6_walker_t *w);
85 static int fib6_walk_continue(struct fib6_walker_t *w);
86
87 /*
88 * A routing update causes an increase of the serial number on the
89 * affected subtree. This allows for cached routes to be asynchronously
90 * tested when modifications are made to the destination cache as a
91 * result of redirects, path MTU changes, etc.
92 */
93
94 static __u32 rt_sernum;
95
96 static DEFINE_TIMER(ip6_fib_timer, fib6_run_gc, 0, 0);
97
98 static struct fib6_walker_t fib6_walker_list = {
99 .prev = &fib6_walker_list,
100 .next = &fib6_walker_list,
101 };
102
103 #define FOR_WALKERS(w) for ((w)=fib6_walker_list.next; (w) != &fib6_walker_list; (w)=(w)->next)
104
105 static inline void fib6_walker_link(struct fib6_walker_t *w)
106 {
107 write_lock_bh(&fib6_walker_lock);
108 w->next = fib6_walker_list.next;
109 w->prev = &fib6_walker_list;
110 w->next->prev = w;
111 w->prev->next = w;
112 write_unlock_bh(&fib6_walker_lock);
113 }
114
115 static inline void fib6_walker_unlink(struct fib6_walker_t *w)
116 {
117 write_lock_bh(&fib6_walker_lock);
118 w->next->prev = w->prev;
119 w->prev->next = w->next;
120 w->prev = w->next = w;
121 write_unlock_bh(&fib6_walker_lock);
122 }
123 static __inline__ u32 fib6_new_sernum(void)
124 {
125 u32 n = ++rt_sernum;
126 if ((__s32)n <= 0)
127 rt_sernum = n = 1;
128 return n;
129 }
130
131 /*
132 * Auxiliary address test functions for the radix tree.
133 *
134 * These assume a 32bit processor (although it will work on
135 * 64bit processors)
136 */
137
138 /*
139 * test bit
140 */
141
142 static __inline__ __be32 addr_bit_set(void *token, int fn_bit)
143 {
144 __be32 *addr = token;
145
146 return htonl(1 << ((~fn_bit)&0x1F)) & addr[fn_bit>>5];
147 }
148
149 static __inline__ struct fib6_node * node_alloc(void)
150 {
151 struct fib6_node *fn;
152
153 fn = kmem_cache_zalloc(fib6_node_kmem, GFP_ATOMIC);
154
155 return fn;
156 }
157
158 static __inline__ void node_free(struct fib6_node * fn)
159 {
160 kmem_cache_free(fib6_node_kmem, fn);
161 }
162
163 static __inline__ void rt6_release(struct rt6_info *rt)
164 {
165 if (atomic_dec_and_test(&rt->rt6i_ref))
166 dst_free(&rt->u.dst);
167 }
168
169 static struct fib6_table fib6_main_tbl = {
170 .tb6_id = RT6_TABLE_MAIN,
171 .tb6_root = {
172 .leaf = &ip6_null_entry,
173 .fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO,
174 },
175 };
176
177 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
178 #define FIB_TABLE_HASHSZ 256
179 #else
180 #define FIB_TABLE_HASHSZ 1
181 #endif
182 static struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ];
183
184 static void fib6_link_table(struct fib6_table *tb)
185 {
186 unsigned int h;
187
188 /*
189 * Initialize table lock at a single place to give lockdep a key,
190 * tables aren't visible prior to being linked to the list.
191 */
192 rwlock_init(&tb->tb6_lock);
193
194 h = tb->tb6_id & (FIB_TABLE_HASHSZ - 1);
195
196 /*
197 * No protection necessary, this is the only list mutatation
198 * operation, tables never disappear once they exist.
199 */
200 hlist_add_head_rcu(&tb->tb6_hlist, &fib_table_hash[h]);
201 }
202
203 #ifdef CONFIG_IPV6_MULTIPLE_TABLES
204 static struct fib6_table fib6_local_tbl = {
205 .tb6_id = RT6_TABLE_LOCAL,
206 .tb6_root = {
207 .leaf = &ip6_null_entry,
208 .fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO,
209 },
210 };
211
212 static struct fib6_table *fib6_alloc_table(u32 id)
213 {
214 struct fib6_table *table;
215
216 table = kzalloc(sizeof(*table), GFP_ATOMIC);
217 if (table != NULL) {
218 table->tb6_id = id;
219 table->tb6_root.leaf = &ip6_null_entry;
220 table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
221 }
222
223 return table;
224 }
225
226 struct fib6_table *fib6_new_table(u32 id)
227 {
228 struct fib6_table *tb;
229
230 if (id == 0)
231 id = RT6_TABLE_MAIN;
232 tb = fib6_get_table(id);
233 if (tb)
234 return tb;
235
236 tb = fib6_alloc_table(id);
237 if (tb != NULL)
238 fib6_link_table(tb);
239
240 return tb;
241 }
242
243 struct fib6_table *fib6_get_table(u32 id)
244 {
245 struct fib6_table *tb;
246 struct hlist_node *node;
247 unsigned int h;
248
249 if (id == 0)
250 id = RT6_TABLE_MAIN;
251 h = id & (FIB_TABLE_HASHSZ - 1);
252 rcu_read_lock();
253 hlist_for_each_entry_rcu(tb, node, &fib_table_hash[h], tb6_hlist) {
254 if (tb->tb6_id == id) {
255 rcu_read_unlock();
256 return tb;
257 }
258 }
259 rcu_read_unlock();
260
261 return NULL;
262 }
263
264 static void __init fib6_tables_init(void)
265 {
266 fib6_link_table(&fib6_main_tbl);
267 fib6_link_table(&fib6_local_tbl);
268 }
269
270 #else
271
272 struct fib6_table *fib6_new_table(u32 id)
273 {
274 return fib6_get_table(id);
275 }
276
277 struct fib6_table *fib6_get_table(u32 id)
278 {
279 return &fib6_main_tbl;
280 }
281
282 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
283 pol_lookup_t lookup)
284 {
285 return (struct dst_entry *) lookup(&fib6_main_tbl, fl, flags);
286 }
287
288 static void __init fib6_tables_init(void)
289 {
290 fib6_link_table(&fib6_main_tbl);
291 }
292
293 #endif
294
295 static int fib6_dump_node(struct fib6_walker_t *w)
296 {
297 int res;
298 struct rt6_info *rt;
299
300 for (rt = w->leaf; rt; rt = rt->u.dst.rt6_next) {
301 res = rt6_dump_route(rt, w->args);
302 if (res < 0) {
303 /* Frame is full, suspend walking */
304 w->leaf = rt;
305 return 1;
306 }
307 BUG_TRAP(res!=0);
308 }
309 w->leaf = NULL;
310 return 0;
311 }
312
313 static void fib6_dump_end(struct netlink_callback *cb)
314 {
315 struct fib6_walker_t *w = (void*)cb->args[2];
316
317 if (w) {
318 cb->args[2] = 0;
319 kfree(w);
320 }
321 cb->done = (void*)cb->args[3];
322 cb->args[1] = 3;
323 }
324
325 static int fib6_dump_done(struct netlink_callback *cb)
326 {
327 fib6_dump_end(cb);
328 return cb->done ? cb->done(cb) : 0;
329 }
330
331 static int fib6_dump_table(struct fib6_table *table, struct sk_buff *skb,
332 struct netlink_callback *cb)
333 {
334 struct fib6_walker_t *w;
335 int res;
336
337 w = (void *)cb->args[2];
338 w->root = &table->tb6_root;
339
340 if (cb->args[4] == 0) {
341 read_lock_bh(&table->tb6_lock);
342 res = fib6_walk(w);
343 read_unlock_bh(&table->tb6_lock);
344 if (res > 0)
345 cb->args[4] = 1;
346 } else {
347 read_lock_bh(&table->tb6_lock);
348 res = fib6_walk_continue(w);
349 read_unlock_bh(&table->tb6_lock);
350 if (res != 0) {
351 if (res < 0)
352 fib6_walker_unlink(w);
353 goto end;
354 }
355 fib6_walker_unlink(w);
356 cb->args[4] = 0;
357 }
358 end:
359 return res;
360 }
361
362 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
363 {
364 struct net *net = skb->sk->sk_net;
365 unsigned int h, s_h;
366 unsigned int e = 0, s_e;
367 struct rt6_rtnl_dump_arg arg;
368 struct fib6_walker_t *w;
369 struct fib6_table *tb;
370 struct hlist_node *node;
371 int res = 0;
372
373 if (net != &init_net)
374 return 0;
375
376 s_h = cb->args[0];
377 s_e = cb->args[1];
378
379 w = (void *)cb->args[2];
380 if (w == NULL) {
381 /* New dump:
382 *
383 * 1. hook callback destructor.
384 */
385 cb->args[3] = (long)cb->done;
386 cb->done = fib6_dump_done;
387
388 /*
389 * 2. allocate and initialize walker.
390 */
391 w = kzalloc(sizeof(*w), GFP_ATOMIC);
392 if (w == NULL)
393 return -ENOMEM;
394 w->func = fib6_dump_node;
395 cb->args[2] = (long)w;
396 }
397
398 arg.skb = skb;
399 arg.cb = cb;
400 w->args = &arg;
401
402 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
403 e = 0;
404 hlist_for_each_entry(tb, node, &fib_table_hash[h], tb6_hlist) {
405 if (e < s_e)
406 goto next;
407 res = fib6_dump_table(tb, skb, cb);
408 if (res != 0)
409 goto out;
410 next:
411 e++;
412 }
413 }
414 out:
415 cb->args[1] = e;
416 cb->args[0] = h;
417
418 res = res < 0 ? res : skb->len;
419 if (res <= 0)
420 fib6_dump_end(cb);
421 return res;
422 }
423
424 /*
425 * Routing Table
426 *
427 * return the appropriate node for a routing tree "add" operation
428 * by either creating and inserting or by returning an existing
429 * node.
430 */
431
432 static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
433 int addrlen, int plen,
434 int offset)
435 {
436 struct fib6_node *fn, *in, *ln;
437 struct fib6_node *pn = NULL;
438 struct rt6key *key;
439 int bit;
440 __be32 dir = 0;
441 __u32 sernum = fib6_new_sernum();
442
443 RT6_TRACE("fib6_add_1\n");
444
445 /* insert node in tree */
446
447 fn = root;
448
449 do {
450 key = (struct rt6key *)((u8 *)fn->leaf + offset);
451
452 /*
453 * Prefix match
454 */
455 if (plen < fn->fn_bit ||
456 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
457 goto insert_above;
458
459 /*
460 * Exact match ?
461 */
462
463 if (plen == fn->fn_bit) {
464 /* clean up an intermediate node */
465 if ((fn->fn_flags & RTN_RTINFO) == 0) {
466 rt6_release(fn->leaf);
467 fn->leaf = NULL;
468 }
469
470 fn->fn_sernum = sernum;
471
472 return fn;
473 }
474
475 /*
476 * We have more bits to go
477 */
478
479 /* Try to walk down on tree. */
480 fn->fn_sernum = sernum;
481 dir = addr_bit_set(addr, fn->fn_bit);
482 pn = fn;
483 fn = dir ? fn->right: fn->left;
484 } while (fn);
485
486 /*
487 * We walked to the bottom of tree.
488 * Create new leaf node without children.
489 */
490
491 ln = node_alloc();
492
493 if (ln == NULL)
494 return NULL;
495 ln->fn_bit = plen;
496
497 ln->parent = pn;
498 ln->fn_sernum = sernum;
499
500 if (dir)
501 pn->right = ln;
502 else
503 pn->left = ln;
504
505 return ln;
506
507
508 insert_above:
509 /*
510 * split since we don't have a common prefix anymore or
511 * we have a less significant route.
512 * we've to insert an intermediate node on the list
513 * this new node will point to the one we need to create
514 * and the current
515 */
516
517 pn = fn->parent;
518
519 /* find 1st bit in difference between the 2 addrs.
520
521 See comment in __ipv6_addr_diff: bit may be an invalid value,
522 but if it is >= plen, the value is ignored in any case.
523 */
524
525 bit = __ipv6_addr_diff(addr, &key->addr, addrlen);
526
527 /*
528 * (intermediate)[in]
529 * / \
530 * (new leaf node)[ln] (old node)[fn]
531 */
532 if (plen > bit) {
533 in = node_alloc();
534 ln = node_alloc();
535
536 if (in == NULL || ln == NULL) {
537 if (in)
538 node_free(in);
539 if (ln)
540 node_free(ln);
541 return NULL;
542 }
543
544 /*
545 * new intermediate node.
546 * RTN_RTINFO will
547 * be off since that an address that chooses one of
548 * the branches would not match less specific routes
549 * in the other branch
550 */
551
552 in->fn_bit = bit;
553
554 in->parent = pn;
555 in->leaf = fn->leaf;
556 atomic_inc(&in->leaf->rt6i_ref);
557
558 in->fn_sernum = sernum;
559
560 /* update parent pointer */
561 if (dir)
562 pn->right = in;
563 else
564 pn->left = in;
565
566 ln->fn_bit = plen;
567
568 ln->parent = in;
569 fn->parent = in;
570
571 ln->fn_sernum = sernum;
572
573 if (addr_bit_set(addr, bit)) {
574 in->right = ln;
575 in->left = fn;
576 } else {
577 in->left = ln;
578 in->right = fn;
579 }
580 } else { /* plen <= bit */
581
582 /*
583 * (new leaf node)[ln]
584 * / \
585 * (old node)[fn] NULL
586 */
587
588 ln = node_alloc();
589
590 if (ln == NULL)
591 return NULL;
592
593 ln->fn_bit = plen;
594
595 ln->parent = pn;
596
597 ln->fn_sernum = sernum;
598
599 if (dir)
600 pn->right = ln;
601 else
602 pn->left = ln;
603
604 if (addr_bit_set(&key->addr, plen))
605 ln->right = fn;
606 else
607 ln->left = fn;
608
609 fn->parent = ln;
610 }
611 return ln;
612 }
613
614 /*
615 * Insert routing information in a node.
616 */
617
618 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
619 struct nl_info *info)
620 {
621 struct rt6_info *iter = NULL;
622 struct rt6_info **ins;
623
624 ins = &fn->leaf;
625
626 for (iter = fn->leaf; iter; iter=iter->u.dst.rt6_next) {
627 /*
628 * Search for duplicates
629 */
630
631 if (iter->rt6i_metric == rt->rt6i_metric) {
632 /*
633 * Same priority level
634 */
635
636 if (iter->rt6i_dev == rt->rt6i_dev &&
637 iter->rt6i_idev == rt->rt6i_idev &&
638 ipv6_addr_equal(&iter->rt6i_gateway,
639 &rt->rt6i_gateway)) {
640 if (!(iter->rt6i_flags&RTF_EXPIRES))
641 return -EEXIST;
642 iter->rt6i_expires = rt->rt6i_expires;
643 if (!(rt->rt6i_flags&RTF_EXPIRES)) {
644 iter->rt6i_flags &= ~RTF_EXPIRES;
645 iter->rt6i_expires = 0;
646 }
647 return -EEXIST;
648 }
649 }
650
651 if (iter->rt6i_metric > rt->rt6i_metric)
652 break;
653
654 ins = &iter->u.dst.rt6_next;
655 }
656
657 /* Reset round-robin state, if necessary */
658 if (ins == &fn->leaf)
659 fn->rr_ptr = NULL;
660
661 /*
662 * insert node
663 */
664
665 rt->u.dst.rt6_next = iter;
666 *ins = rt;
667 rt->rt6i_node = fn;
668 atomic_inc(&rt->rt6i_ref);
669 inet6_rt_notify(RTM_NEWROUTE, rt, info);
670 rt6_stats.fib_rt_entries++;
671
672 if ((fn->fn_flags & RTN_RTINFO) == 0) {
673 rt6_stats.fib_route_nodes++;
674 fn->fn_flags |= RTN_RTINFO;
675 }
676
677 return 0;
678 }
679
680 static __inline__ void fib6_start_gc(struct rt6_info *rt)
681 {
682 if (ip6_fib_timer.expires == 0 &&
683 (rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE)))
684 mod_timer(&ip6_fib_timer, jiffies +
685 init_net.ipv6.sysctl.ip6_rt_gc_interval);
686 }
687
688 void fib6_force_start_gc(void)
689 {
690 if (ip6_fib_timer.expires == 0)
691 mod_timer(&ip6_fib_timer, jiffies +
692 init_net.ipv6.sysctl.ip6_rt_gc_interval);
693 }
694
695 /*
696 * Add routing information to the routing tree.
697 * <destination addr>/<source addr>
698 * with source addr info in sub-trees
699 */
700
701 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
702 {
703 struct fib6_node *fn, *pn = NULL;
704 int err = -ENOMEM;
705
706 fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
707 rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst));
708
709 if (fn == NULL)
710 goto out;
711
712 pn = fn;
713
714 #ifdef CONFIG_IPV6_SUBTREES
715 if (rt->rt6i_src.plen) {
716 struct fib6_node *sn;
717
718 if (fn->subtree == NULL) {
719 struct fib6_node *sfn;
720
721 /*
722 * Create subtree.
723 *
724 * fn[main tree]
725 * |
726 * sfn[subtree root]
727 * \
728 * sn[new leaf node]
729 */
730
731 /* Create subtree root node */
732 sfn = node_alloc();
733 if (sfn == NULL)
734 goto st_failure;
735
736 sfn->leaf = &ip6_null_entry;
737 atomic_inc(&ip6_null_entry.rt6i_ref);
738 sfn->fn_flags = RTN_ROOT;
739 sfn->fn_sernum = fib6_new_sernum();
740
741 /* Now add the first leaf node to new subtree */
742
743 sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
744 sizeof(struct in6_addr), rt->rt6i_src.plen,
745 offsetof(struct rt6_info, rt6i_src));
746
747 if (sn == NULL) {
748 /* If it is failed, discard just allocated
749 root, and then (in st_failure) stale node
750 in main tree.
751 */
752 node_free(sfn);
753 goto st_failure;
754 }
755
756 /* Now link new subtree to main tree */
757 sfn->parent = fn;
758 fn->subtree = sfn;
759 } else {
760 sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
761 sizeof(struct in6_addr), rt->rt6i_src.plen,
762 offsetof(struct rt6_info, rt6i_src));
763
764 if (sn == NULL)
765 goto st_failure;
766 }
767
768 if (fn->leaf == NULL) {
769 fn->leaf = rt;
770 atomic_inc(&rt->rt6i_ref);
771 }
772 fn = sn;
773 }
774 #endif
775
776 err = fib6_add_rt2node(fn, rt, info);
777
778 if (err == 0) {
779 fib6_start_gc(rt);
780 if (!(rt->rt6i_flags&RTF_CACHE))
781 fib6_prune_clones(pn, rt);
782 }
783
784 out:
785 if (err) {
786 #ifdef CONFIG_IPV6_SUBTREES
787 /*
788 * If fib6_add_1 has cleared the old leaf pointer in the
789 * super-tree leaf node we have to find a new one for it.
790 */
791 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
792 pn->leaf = fib6_find_prefix(pn);
793 #if RT6_DEBUG >= 2
794 if (!pn->leaf) {
795 BUG_TRAP(pn->leaf != NULL);
796 pn->leaf = &ip6_null_entry;
797 }
798 #endif
799 atomic_inc(&pn->leaf->rt6i_ref);
800 }
801 #endif
802 dst_free(&rt->u.dst);
803 }
804 return err;
805
806 #ifdef CONFIG_IPV6_SUBTREES
807 /* Subtree creation failed, probably main tree node
808 is orphan. If it is, shoot it.
809 */
810 st_failure:
811 if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
812 fib6_repair_tree(fn);
813 dst_free(&rt->u.dst);
814 return err;
815 #endif
816 }
817
818 /*
819 * Routing tree lookup
820 *
821 */
822
823 struct lookup_args {
824 int offset; /* key offset on rt6_info */
825 struct in6_addr *addr; /* search key */
826 };
827
828 static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
829 struct lookup_args *args)
830 {
831 struct fib6_node *fn;
832 __be32 dir;
833
834 if (unlikely(args->offset == 0))
835 return NULL;
836
837 /*
838 * Descend on a tree
839 */
840
841 fn = root;
842
843 for (;;) {
844 struct fib6_node *next;
845
846 dir = addr_bit_set(args->addr, fn->fn_bit);
847
848 next = dir ? fn->right : fn->left;
849
850 if (next) {
851 fn = next;
852 continue;
853 }
854
855 break;
856 }
857
858 while(fn) {
859 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
860 struct rt6key *key;
861
862 key = (struct rt6key *) ((u8 *) fn->leaf +
863 args->offset);
864
865 if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
866 #ifdef CONFIG_IPV6_SUBTREES
867 if (fn->subtree)
868 fn = fib6_lookup_1(fn->subtree, args + 1);
869 #endif
870 if (!fn || fn->fn_flags & RTN_RTINFO)
871 return fn;
872 }
873 }
874
875 if (fn->fn_flags & RTN_ROOT)
876 break;
877
878 fn = fn->parent;
879 }
880
881 return NULL;
882 }
883
884 struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr,
885 struct in6_addr *saddr)
886 {
887 struct fib6_node *fn;
888 struct lookup_args args[] = {
889 {
890 .offset = offsetof(struct rt6_info, rt6i_dst),
891 .addr = daddr,
892 },
893 #ifdef CONFIG_IPV6_SUBTREES
894 {
895 .offset = offsetof(struct rt6_info, rt6i_src),
896 .addr = saddr,
897 },
898 #endif
899 {
900 .offset = 0, /* sentinel */
901 }
902 };
903
904 fn = fib6_lookup_1(root, daddr ? args : args + 1);
905
906 if (fn == NULL || fn->fn_flags & RTN_TL_ROOT)
907 fn = root;
908
909 return fn;
910 }
911
912 /*
913 * Get node with specified destination prefix (and source prefix,
914 * if subtrees are used)
915 */
916
917
918 static struct fib6_node * fib6_locate_1(struct fib6_node *root,
919 struct in6_addr *addr,
920 int plen, int offset)
921 {
922 struct fib6_node *fn;
923
924 for (fn = root; fn ; ) {
925 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
926
927 /*
928 * Prefix match
929 */
930 if (plen < fn->fn_bit ||
931 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
932 return NULL;
933
934 if (plen == fn->fn_bit)
935 return fn;
936
937 /*
938 * We have more bits to go
939 */
940 if (addr_bit_set(addr, fn->fn_bit))
941 fn = fn->right;
942 else
943 fn = fn->left;
944 }
945 return NULL;
946 }
947
948 struct fib6_node * fib6_locate(struct fib6_node *root,
949 struct in6_addr *daddr, int dst_len,
950 struct in6_addr *saddr, int src_len)
951 {
952 struct fib6_node *fn;
953
954 fn = fib6_locate_1(root, daddr, dst_len,
955 offsetof(struct rt6_info, rt6i_dst));
956
957 #ifdef CONFIG_IPV6_SUBTREES
958 if (src_len) {
959 BUG_TRAP(saddr!=NULL);
960 if (fn && fn->subtree)
961 fn = fib6_locate_1(fn->subtree, saddr, src_len,
962 offsetof(struct rt6_info, rt6i_src));
963 }
964 #endif
965
966 if (fn && fn->fn_flags&RTN_RTINFO)
967 return fn;
968
969 return NULL;
970 }
971
972
973 /*
974 * Deletion
975 *
976 */
977
978 static struct rt6_info * fib6_find_prefix(struct fib6_node *fn)
979 {
980 if (fn->fn_flags&RTN_ROOT)
981 return &ip6_null_entry;
982
983 while(fn) {
984 if(fn->left)
985 return fn->left->leaf;
986
987 if(fn->right)
988 return fn->right->leaf;
989
990 fn = FIB6_SUBTREE(fn);
991 }
992 return NULL;
993 }
994
995 /*
996 * Called to trim the tree of intermediate nodes when possible. "fn"
997 * is the node we want to try and remove.
998 */
999
1000 static struct fib6_node * fib6_repair_tree(struct fib6_node *fn)
1001 {
1002 int children;
1003 int nstate;
1004 struct fib6_node *child, *pn;
1005 struct fib6_walker_t *w;
1006 int iter = 0;
1007
1008 for (;;) {
1009 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1010 iter++;
1011
1012 BUG_TRAP(!(fn->fn_flags&RTN_RTINFO));
1013 BUG_TRAP(!(fn->fn_flags&RTN_TL_ROOT));
1014 BUG_TRAP(fn->leaf==NULL);
1015
1016 children = 0;
1017 child = NULL;
1018 if (fn->right) child = fn->right, children |= 1;
1019 if (fn->left) child = fn->left, children |= 2;
1020
1021 if (children == 3 || FIB6_SUBTREE(fn)
1022 #ifdef CONFIG_IPV6_SUBTREES
1023 /* Subtree root (i.e. fn) may have one child */
1024 || (children && fn->fn_flags&RTN_ROOT)
1025 #endif
1026 ) {
1027 fn->leaf = fib6_find_prefix(fn);
1028 #if RT6_DEBUG >= 2
1029 if (fn->leaf==NULL) {
1030 BUG_TRAP(fn->leaf);
1031 fn->leaf = &ip6_null_entry;
1032 }
1033 #endif
1034 atomic_inc(&fn->leaf->rt6i_ref);
1035 return fn->parent;
1036 }
1037
1038 pn = fn->parent;
1039 #ifdef CONFIG_IPV6_SUBTREES
1040 if (FIB6_SUBTREE(pn) == fn) {
1041 BUG_TRAP(fn->fn_flags&RTN_ROOT);
1042 FIB6_SUBTREE(pn) = NULL;
1043 nstate = FWS_L;
1044 } else {
1045 BUG_TRAP(!(fn->fn_flags&RTN_ROOT));
1046 #endif
1047 if (pn->right == fn) pn->right = child;
1048 else if (pn->left == fn) pn->left = child;
1049 #if RT6_DEBUG >= 2
1050 else BUG_TRAP(0);
1051 #endif
1052 if (child)
1053 child->parent = pn;
1054 nstate = FWS_R;
1055 #ifdef CONFIG_IPV6_SUBTREES
1056 }
1057 #endif
1058
1059 read_lock(&fib6_walker_lock);
1060 FOR_WALKERS(w) {
1061 if (child == NULL) {
1062 if (w->root == fn) {
1063 w->root = w->node = NULL;
1064 RT6_TRACE("W %p adjusted by delroot 1\n", w);
1065 } else if (w->node == fn) {
1066 RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1067 w->node = pn;
1068 w->state = nstate;
1069 }
1070 } else {
1071 if (w->root == fn) {
1072 w->root = child;
1073 RT6_TRACE("W %p adjusted by delroot 2\n", w);
1074 }
1075 if (w->node == fn) {
1076 w->node = child;
1077 if (children&2) {
1078 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1079 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1080 } else {
1081 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1082 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1083 }
1084 }
1085 }
1086 }
1087 read_unlock(&fib6_walker_lock);
1088
1089 node_free(fn);
1090 if (pn->fn_flags&RTN_RTINFO || FIB6_SUBTREE(pn))
1091 return pn;
1092
1093 rt6_release(pn->leaf);
1094 pn->leaf = NULL;
1095 fn = pn;
1096 }
1097 }
1098
1099 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1100 struct nl_info *info)
1101 {
1102 struct fib6_walker_t *w;
1103 struct rt6_info *rt = *rtp;
1104
1105 RT6_TRACE("fib6_del_route\n");
1106
1107 /* Unlink it */
1108 *rtp = rt->u.dst.rt6_next;
1109 rt->rt6i_node = NULL;
1110 rt6_stats.fib_rt_entries--;
1111 rt6_stats.fib_discarded_routes++;
1112
1113 /* Reset round-robin state, if necessary */
1114 if (fn->rr_ptr == rt)
1115 fn->rr_ptr = NULL;
1116
1117 /* Adjust walkers */
1118 read_lock(&fib6_walker_lock);
1119 FOR_WALKERS(w) {
1120 if (w->state == FWS_C && w->leaf == rt) {
1121 RT6_TRACE("walker %p adjusted by delroute\n", w);
1122 w->leaf = rt->u.dst.rt6_next;
1123 if (w->leaf == NULL)
1124 w->state = FWS_U;
1125 }
1126 }
1127 read_unlock(&fib6_walker_lock);
1128
1129 rt->u.dst.rt6_next = NULL;
1130
1131 /* If it was last route, expunge its radix tree node */
1132 if (fn->leaf == NULL) {
1133 fn->fn_flags &= ~RTN_RTINFO;
1134 rt6_stats.fib_route_nodes--;
1135 fn = fib6_repair_tree(fn);
1136 }
1137
1138 if (atomic_read(&rt->rt6i_ref) != 1) {
1139 /* This route is used as dummy address holder in some split
1140 * nodes. It is not leaked, but it still holds other resources,
1141 * which must be released in time. So, scan ascendant nodes
1142 * and replace dummy references to this route with references
1143 * to still alive ones.
1144 */
1145 while (fn) {
1146 if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) {
1147 fn->leaf = fib6_find_prefix(fn);
1148 atomic_inc(&fn->leaf->rt6i_ref);
1149 rt6_release(rt);
1150 }
1151 fn = fn->parent;
1152 }
1153 /* No more references are possible at this point. */
1154 BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
1155 }
1156
1157 inet6_rt_notify(RTM_DELROUTE, rt, info);
1158 rt6_release(rt);
1159 }
1160
1161 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1162 {
1163 struct fib6_node *fn = rt->rt6i_node;
1164 struct rt6_info **rtp;
1165
1166 #if RT6_DEBUG >= 2
1167 if (rt->u.dst.obsolete>0) {
1168 BUG_TRAP(fn==NULL);
1169 return -ENOENT;
1170 }
1171 #endif
1172 if (fn == NULL || rt == &ip6_null_entry)
1173 return -ENOENT;
1174
1175 BUG_TRAP(fn->fn_flags&RTN_RTINFO);
1176
1177 if (!(rt->rt6i_flags&RTF_CACHE)) {
1178 struct fib6_node *pn = fn;
1179 #ifdef CONFIG_IPV6_SUBTREES
1180 /* clones of this route might be in another subtree */
1181 if (rt->rt6i_src.plen) {
1182 while (!(pn->fn_flags&RTN_ROOT))
1183 pn = pn->parent;
1184 pn = pn->parent;
1185 }
1186 #endif
1187 fib6_prune_clones(pn, rt);
1188 }
1189
1190 /*
1191 * Walk the leaf entries looking for ourself
1192 */
1193
1194 for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.dst.rt6_next) {
1195 if (*rtp == rt) {
1196 fib6_del_route(fn, rtp, info);
1197 return 0;
1198 }
1199 }
1200 return -ENOENT;
1201 }
1202
1203 /*
1204 * Tree traversal function.
1205 *
1206 * Certainly, it is not interrupt safe.
1207 * However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1208 * It means, that we can modify tree during walking
1209 * and use this function for garbage collection, clone pruning,
1210 * cleaning tree when a device goes down etc. etc.
1211 *
1212 * It guarantees that every node will be traversed,
1213 * and that it will be traversed only once.
1214 *
1215 * Callback function w->func may return:
1216 * 0 -> continue walking.
1217 * positive value -> walking is suspended (used by tree dumps,
1218 * and probably by gc, if it will be split to several slices)
1219 * negative value -> terminate walking.
1220 *
1221 * The function itself returns:
1222 * 0 -> walk is complete.
1223 * >0 -> walk is incomplete (i.e. suspended)
1224 * <0 -> walk is terminated by an error.
1225 */
1226
1227 static int fib6_walk_continue(struct fib6_walker_t *w)
1228 {
1229 struct fib6_node *fn, *pn;
1230
1231 for (;;) {
1232 fn = w->node;
1233 if (fn == NULL)
1234 return 0;
1235
1236 if (w->prune && fn != w->root &&
1237 fn->fn_flags&RTN_RTINFO && w->state < FWS_C) {
1238 w->state = FWS_C;
1239 w->leaf = fn->leaf;
1240 }
1241 switch (w->state) {
1242 #ifdef CONFIG_IPV6_SUBTREES
1243 case FWS_S:
1244 if (FIB6_SUBTREE(fn)) {
1245 w->node = FIB6_SUBTREE(fn);
1246 continue;
1247 }
1248 w->state = FWS_L;
1249 #endif
1250 case FWS_L:
1251 if (fn->left) {
1252 w->node = fn->left;
1253 w->state = FWS_INIT;
1254 continue;
1255 }
1256 w->state = FWS_R;
1257 case FWS_R:
1258 if (fn->right) {
1259 w->node = fn->right;
1260 w->state = FWS_INIT;
1261 continue;
1262 }
1263 w->state = FWS_C;
1264 w->leaf = fn->leaf;
1265 case FWS_C:
1266 if (w->leaf && fn->fn_flags&RTN_RTINFO) {
1267 int err = w->func(w);
1268 if (err)
1269 return err;
1270 continue;
1271 }
1272 w->state = FWS_U;
1273 case FWS_U:
1274 if (fn == w->root)
1275 return 0;
1276 pn = fn->parent;
1277 w->node = pn;
1278 #ifdef CONFIG_IPV6_SUBTREES
1279 if (FIB6_SUBTREE(pn) == fn) {
1280 BUG_TRAP(fn->fn_flags&RTN_ROOT);
1281 w->state = FWS_L;
1282 continue;
1283 }
1284 #endif
1285 if (pn->left == fn) {
1286 w->state = FWS_R;
1287 continue;
1288 }
1289 if (pn->right == fn) {
1290 w->state = FWS_C;
1291 w->leaf = w->node->leaf;
1292 continue;
1293 }
1294 #if RT6_DEBUG >= 2
1295 BUG_TRAP(0);
1296 #endif
1297 }
1298 }
1299 }
1300
1301 static int fib6_walk(struct fib6_walker_t *w)
1302 {
1303 int res;
1304
1305 w->state = FWS_INIT;
1306 w->node = w->root;
1307
1308 fib6_walker_link(w);
1309 res = fib6_walk_continue(w);
1310 if (res <= 0)
1311 fib6_walker_unlink(w);
1312 return res;
1313 }
1314
1315 static int fib6_clean_node(struct fib6_walker_t *w)
1316 {
1317 struct nl_info info = {
1318 .nl_net = &init_net,
1319 };
1320 int res;
1321 struct rt6_info *rt;
1322 struct fib6_cleaner_t *c = container_of(w, struct fib6_cleaner_t, w);
1323
1324 for (rt = w->leaf; rt; rt = rt->u.dst.rt6_next) {
1325 res = c->func(rt, c->arg);
1326 if (res < 0) {
1327 w->leaf = rt;
1328 res = fib6_del(rt, &info);
1329 if (res) {
1330 #if RT6_DEBUG >= 2
1331 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
1332 #endif
1333 continue;
1334 }
1335 return 0;
1336 }
1337 BUG_TRAP(res==0);
1338 }
1339 w->leaf = rt;
1340 return 0;
1341 }
1342
1343 /*
1344 * Convenient frontend to tree walker.
1345 *
1346 * func is called on each route.
1347 * It may return -1 -> delete this route.
1348 * 0 -> continue walking
1349 *
1350 * prune==1 -> only immediate children of node (certainly,
1351 * ignoring pure split nodes) will be scanned.
1352 */
1353
1354 static void fib6_clean_tree(struct fib6_node *root,
1355 int (*func)(struct rt6_info *, void *arg),
1356 int prune, void *arg)
1357 {
1358 struct fib6_cleaner_t c;
1359
1360 c.w.root = root;
1361 c.w.func = fib6_clean_node;
1362 c.w.prune = prune;
1363 c.func = func;
1364 c.arg = arg;
1365
1366 fib6_walk(&c.w);
1367 }
1368
1369 void fib6_clean_all(int (*func)(struct rt6_info *, void *arg),
1370 int prune, void *arg)
1371 {
1372 struct fib6_table *table;
1373 struct hlist_node *node;
1374 unsigned int h;
1375
1376 rcu_read_lock();
1377 for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
1378 hlist_for_each_entry_rcu(table, node, &fib_table_hash[h],
1379 tb6_hlist) {
1380 write_lock_bh(&table->tb6_lock);
1381 fib6_clean_tree(&table->tb6_root, func, prune, arg);
1382 write_unlock_bh(&table->tb6_lock);
1383 }
1384 }
1385 rcu_read_unlock();
1386 }
1387
1388 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1389 {
1390 if (rt->rt6i_flags & RTF_CACHE) {
1391 RT6_TRACE("pruning clone %p\n", rt);
1392 return -1;
1393 }
1394
1395 return 0;
1396 }
1397
1398 static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt)
1399 {
1400 fib6_clean_tree(fn, fib6_prune_clone, 1, rt);
1401 }
1402
1403 /*
1404 * Garbage collection
1405 */
1406
1407 static struct fib6_gc_args
1408 {
1409 int timeout;
1410 int more;
1411 } gc_args;
1412
1413 static int fib6_age(struct rt6_info *rt, void *arg)
1414 {
1415 unsigned long now = jiffies;
1416
1417 /*
1418 * check addrconf expiration here.
1419 * Routes are expired even if they are in use.
1420 *
1421 * Also age clones. Note, that clones are aged out
1422 * only if they are not in use now.
1423 */
1424
1425 if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {
1426 if (time_after(now, rt->rt6i_expires)) {
1427 RT6_TRACE("expiring %p\n", rt);
1428 return -1;
1429 }
1430 gc_args.more++;
1431 } else if (rt->rt6i_flags & RTF_CACHE) {
1432 if (atomic_read(&rt->u.dst.__refcnt) == 0 &&
1433 time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) {
1434 RT6_TRACE("aging clone %p\n", rt);
1435 return -1;
1436 } else if ((rt->rt6i_flags & RTF_GATEWAY) &&
1437 (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) {
1438 RT6_TRACE("purging route %p via non-router but gateway\n",
1439 rt);
1440 return -1;
1441 }
1442 gc_args.more++;
1443 }
1444
1445 return 0;
1446 }
1447
1448 static DEFINE_SPINLOCK(fib6_gc_lock);
1449
1450 void fib6_run_gc(unsigned long dummy)
1451 {
1452 if (dummy != ~0UL) {
1453 spin_lock_bh(&fib6_gc_lock);
1454 gc_args.timeout = dummy ? (int)dummy :
1455 init_net.ipv6.sysctl.ip6_rt_gc_interval;
1456 } else {
1457 local_bh_disable();
1458 if (!spin_trylock(&fib6_gc_lock)) {
1459 mod_timer(&ip6_fib_timer, jiffies + HZ);
1460 local_bh_enable();
1461 return;
1462 }
1463 gc_args.timeout = init_net.ipv6.sysctl.ip6_rt_gc_interval;
1464 }
1465 gc_args.more = 0;
1466
1467 ndisc_dst_gc(&gc_args.more);
1468 fib6_clean_all(fib6_age, 0, NULL);
1469
1470 if (gc_args.more)
1471 mod_timer(&ip6_fib_timer, jiffies +
1472 init_net.ipv6.sysctl.ip6_rt_gc_interval);
1473 else {
1474 del_timer(&ip6_fib_timer);
1475 ip6_fib_timer.expires = 0;
1476 }
1477 spin_unlock_bh(&fib6_gc_lock);
1478 }
1479
1480 int __init fib6_init(void)
1481 {
1482 int ret;
1483 fib6_node_kmem = kmem_cache_create("fib6_nodes",
1484 sizeof(struct fib6_node),
1485 0, SLAB_HWCACHE_ALIGN,
1486 NULL);
1487 if (!fib6_node_kmem)
1488 return -ENOMEM;
1489
1490 fib6_tables_init();
1491
1492 ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib);
1493 if (ret)
1494 goto out_kmem_cache_create;
1495 out:
1496 return ret;
1497
1498 out_kmem_cache_create:
1499 kmem_cache_destroy(fib6_node_kmem);
1500 goto out;
1501 }
1502
1503 void fib6_gc_cleanup(void)
1504 {
1505 del_timer(&ip6_fib_timer);
1506 kmem_cache_destroy(fib6_node_kmem);
1507 }
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