?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Linux 2.6.21.1
[linux/fpc-iii.git] / net / ipv6 / ip6_fib.c
blob268f476ef3dbe34aafaedc9d089d381da76f7667
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 int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
363 {
364 unsigned int h, s_h;
365 unsigned int e = 0, s_e;
366 struct rt6_rtnl_dump_arg arg;
367 struct fib6_walker_t *w;
368 struct fib6_table *tb;
369 struct hlist_node *node;
370 int res = 0;
371
372 s_h = cb->args[0];
373 s_e = cb->args[1];
374
375 w = (void *)cb->args[2];
376 if (w == NULL) {
377 /* New dump:
378 *
379 * 1. hook callback destructor.
380 */
381 cb->args[3] = (long)cb->done;
382 cb->done = fib6_dump_done;
383
384 /*
385 * 2. allocate and initialize walker.
386 */
387 w = kzalloc(sizeof(*w), GFP_ATOMIC);
388 if (w == NULL)
389 return -ENOMEM;
390 w->func = fib6_dump_node;
391 cb->args[2] = (long)w;
392 }
393
394 arg.skb = skb;
395 arg.cb = cb;
396 w->args = &arg;
397
398 for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
399 e = 0;
400 hlist_for_each_entry(tb, node, &fib_table_hash[h], tb6_hlist) {
401 if (e < s_e)
402 goto next;
403 res = fib6_dump_table(tb, skb, cb);
404 if (res != 0)
405 goto out;
406 next:
407 e++;
408 }
409 }
410 out:
411 cb->args[1] = e;
412 cb->args[0] = h;
413
414 res = res < 0 ? res : skb->len;
415 if (res <= 0)
416 fib6_dump_end(cb);
417 return res;
418 }
419
420 /*
421 * Routing Table
422 *
423 * return the appropriate node for a routing tree "add" operation
424 * by either creating and inserting or by returning an existing
425 * node.
426 */
427
428 static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
429 int addrlen, int plen,
430 int offset)
431 {
432 struct fib6_node *fn, *in, *ln;
433 struct fib6_node *pn = NULL;
434 struct rt6key *key;
435 int bit;
436 __be32 dir = 0;
437 __u32 sernum = fib6_new_sernum();
438
439 RT6_TRACE("fib6_add_1\n");
440
441 /* insert node in tree */
442
443 fn = root;
444
445 do {
446 key = (struct rt6key *)((u8 *)fn->leaf + offset);
447
448 /*
449 * Prefix match
450 */
451 if (plen < fn->fn_bit ||
452 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
453 goto insert_above;
454
455 /*
456 * Exact match ?
457 */
458
459 if (plen == fn->fn_bit) {
460 /* clean up an intermediate node */
461 if ((fn->fn_flags & RTN_RTINFO) == 0) {
462 rt6_release(fn->leaf);
463 fn->leaf = NULL;
464 }
465
466 fn->fn_sernum = sernum;
467
468 return fn;
469 }
470
471 /*
472 * We have more bits to go
473 */
474
475 /* Try to walk down on tree. */
476 fn->fn_sernum = sernum;
477 dir = addr_bit_set(addr, fn->fn_bit);
478 pn = fn;
479 fn = dir ? fn->right: fn->left;
480 } while (fn);
481
482 /*
483 * We walked to the bottom of tree.
484 * Create new leaf node without children.
485 */
486
487 ln = node_alloc();
488
489 if (ln == NULL)
490 return NULL;
491 ln->fn_bit = plen;
492
493 ln->parent = pn;
494 ln->fn_sernum = sernum;
495
496 if (dir)
497 pn->right = ln;
498 else
499 pn->left = ln;
500
501 return ln;
502
503
504 insert_above:
505 /*
506 * split since we don't have a common prefix anymore or
507 * we have a less significant route.
508 * we've to insert an intermediate node on the list
509 * this new node will point to the one we need to create
510 * and the current
511 */
512
513 pn = fn->parent;
514
515 /* find 1st bit in difference between the 2 addrs.
516
517 See comment in __ipv6_addr_diff: bit may be an invalid value,
518 but if it is >= plen, the value is ignored in any case.
519 */
520
521 bit = __ipv6_addr_diff(addr, &key->addr, addrlen);
522
523 /*
524 * (intermediate)[in]
525 * / \
526 * (new leaf node)[ln] (old node)[fn]
527 */
528 if (plen > bit) {
529 in = node_alloc();
530 ln = node_alloc();
531
532 if (in == NULL || ln == NULL) {
533 if (in)
534 node_free(in);
535 if (ln)
536 node_free(ln);
537 return NULL;
538 }
539
540 /*
541 * new intermediate node.
542 * RTN_RTINFO will
543 * be off since that an address that chooses one of
544 * the branches would not match less specific routes
545 * in the other branch
546 */
547
548 in->fn_bit = bit;
549
550 in->parent = pn;
551 in->leaf = fn->leaf;
552 atomic_inc(&in->leaf->rt6i_ref);
553
554 in->fn_sernum = sernum;
555
556 /* update parent pointer */
557 if (dir)
558 pn->right = in;
559 else
560 pn->left = in;
561
562 ln->fn_bit = plen;
563
564 ln->parent = in;
565 fn->parent = in;
566
567 ln->fn_sernum = sernum;
568
569 if (addr_bit_set(addr, bit)) {
570 in->right = ln;
571 in->left = fn;
572 } else {
573 in->left = ln;
574 in->right = fn;
575 }
576 } else { /* plen <= bit */
577
578 /*
579 * (new leaf node)[ln]
580 * / \
581 * (old node)[fn] NULL
582 */
583
584 ln = node_alloc();
585
586 if (ln == NULL)
587 return NULL;
588
589 ln->fn_bit = plen;
590
591 ln->parent = pn;
592
593 ln->fn_sernum = sernum;
594
595 if (dir)
596 pn->right = ln;
597 else
598 pn->left = ln;
599
600 if (addr_bit_set(&key->addr, plen))
601 ln->right = fn;
602 else
603 ln->left = fn;
604
605 fn->parent = ln;
606 }
607 return ln;
608 }
609
610 /*
611 * Insert routing information in a node.
612 */
613
614 static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
615 struct nl_info *info)
616 {
617 struct rt6_info *iter = NULL;
618 struct rt6_info **ins;
619
620 ins = &fn->leaf;
621
622 if (fn->fn_flags&RTN_TL_ROOT &&
623 fn->leaf == &ip6_null_entry &&
624 !(rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ){
625 fn->leaf = rt;
626 rt->u.dst.rt6_next = NULL;
627 goto out;
628 }
629
630 for (iter = fn->leaf; iter; iter=iter->u.dst.rt6_next) {
631 /*
632 * Search for duplicates
633 */
634
635 if (iter->rt6i_metric == rt->rt6i_metric) {
636 /*
637 * Same priority level
638 */
639
640 if (iter->rt6i_dev == rt->rt6i_dev &&
641 iter->rt6i_idev == rt->rt6i_idev &&
642 ipv6_addr_equal(&iter->rt6i_gateway,
643 &rt->rt6i_gateway)) {
644 if (!(iter->rt6i_flags&RTF_EXPIRES))
645 return -EEXIST;
646 iter->rt6i_expires = rt->rt6i_expires;
647 if (!(rt->rt6i_flags&RTF_EXPIRES)) {
648 iter->rt6i_flags &= ~RTF_EXPIRES;
649 iter->rt6i_expires = 0;
650 }
651 return -EEXIST;
652 }
653 }
654
655 if (iter->rt6i_metric > rt->rt6i_metric)
656 break;
657
658 ins = &iter->u.dst.rt6_next;
659 }
660
661 /* Reset round-robin state, if necessary */
662 if (ins == &fn->leaf)
663 fn->rr_ptr = NULL;
664
665 /*
666 * insert node
667 */
668
669 out:
670 rt->u.dst.rt6_next = iter;
671 *ins = rt;
672 rt->rt6i_node = fn;
673 atomic_inc(&rt->rt6i_ref);
674 inet6_rt_notify(RTM_NEWROUTE, rt, info);
675 rt6_stats.fib_rt_entries++;
676
677 if ((fn->fn_flags & RTN_RTINFO) == 0) {
678 rt6_stats.fib_route_nodes++;
679 fn->fn_flags |= RTN_RTINFO;
680 }
681
682 return 0;
683 }
684
685 static __inline__ void fib6_start_gc(struct rt6_info *rt)
686 {
687 if (ip6_fib_timer.expires == 0 &&
688 (rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE)))
689 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
690 }
691
692 void fib6_force_start_gc(void)
693 {
694 if (ip6_fib_timer.expires == 0)
695 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
696 }
697
698 /*
699 * Add routing information to the routing tree.
700 * <destination addr>/<source addr>
701 * with source addr info in sub-trees
702 */
703
704 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
705 {
706 struct fib6_node *fn, *pn = NULL;
707 int err = -ENOMEM;
708
709 fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
710 rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst));
711
712 if (fn == NULL)
713 goto out;
714
715 pn = fn;
716
717 #ifdef CONFIG_IPV6_SUBTREES
718 if (rt->rt6i_src.plen) {
719 struct fib6_node *sn;
720
721 if (fn->subtree == NULL) {
722 struct fib6_node *sfn;
723
724 /*
725 * Create subtree.
726 *
727 * fn[main tree]
728 * |
729 * sfn[subtree root]
730 * \
731 * sn[new leaf node]
732 */
733
734 /* Create subtree root node */
735 sfn = node_alloc();
736 if (sfn == NULL)
737 goto st_failure;
738
739 sfn->leaf = &ip6_null_entry;
740 atomic_inc(&ip6_null_entry.rt6i_ref);
741 sfn->fn_flags = RTN_ROOT;
742 sfn->fn_sernum = fib6_new_sernum();
743
744 /* Now add the first leaf node to new subtree */
745
746 sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
747 sizeof(struct in6_addr), rt->rt6i_src.plen,
748 offsetof(struct rt6_info, rt6i_src));
749
750 if (sn == NULL) {
751 /* If it is failed, discard just allocated
752 root, and then (in st_failure) stale node
753 in main tree.
754 */
755 node_free(sfn);
756 goto st_failure;
757 }
758
759 /* Now link new subtree to main tree */
760 sfn->parent = fn;
761 fn->subtree = sfn;
762 } else {
763 sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
764 sizeof(struct in6_addr), rt->rt6i_src.plen,
765 offsetof(struct rt6_info, rt6i_src));
766
767 if (sn == NULL)
768 goto st_failure;
769 }
770
771 if (fn->leaf == NULL) {
772 fn->leaf = rt;
773 atomic_inc(&rt->rt6i_ref);
774 }
775 fn = sn;
776 }
777 #endif
778
779 err = fib6_add_rt2node(fn, rt, info);
780
781 if (err == 0) {
782 fib6_start_gc(rt);
783 if (!(rt->rt6i_flags&RTF_CACHE))
784 fib6_prune_clones(pn, rt);
785 }
786
787 out:
788 if (err) {
789 #ifdef CONFIG_IPV6_SUBTREES
790 /*
791 * If fib6_add_1 has cleared the old leaf pointer in the
792 * super-tree leaf node we have to find a new one for it.
793 */
794 if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
795 pn->leaf = fib6_find_prefix(pn);
796 #if RT6_DEBUG >= 2
797 if (!pn->leaf) {
798 BUG_TRAP(pn->leaf != NULL);
799 pn->leaf = &ip6_null_entry;
800 }
801 #endif
802 atomic_inc(&pn->leaf->rt6i_ref);
803 }
804 #endif
805 dst_free(&rt->u.dst);
806 }
807 return err;
808
809 #ifdef CONFIG_IPV6_SUBTREES
810 /* Subtree creation failed, probably main tree node
811 is orphan. If it is, shoot it.
812 */
813 st_failure:
814 if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
815 fib6_repair_tree(fn);
816 dst_free(&rt->u.dst);
817 return err;
818 #endif
819 }
820
821 /*
822 * Routing tree lookup
823 *
824 */
825
826 struct lookup_args {
827 int offset; /* key offset on rt6_info */
828 struct in6_addr *addr; /* search key */
829 };
830
831 static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
832 struct lookup_args *args)
833 {
834 struct fib6_node *fn;
835 __be32 dir;
836
837 if (unlikely(args->offset == 0))
838 return NULL;
839
840 /*
841 * Descend on a tree
842 */
843
844 fn = root;
845
846 for (;;) {
847 struct fib6_node *next;
848
849 dir = addr_bit_set(args->addr, fn->fn_bit);
850
851 next = dir ? fn->right : fn->left;
852
853 if (next) {
854 fn = next;
855 continue;
856 }
857
858 break;
859 }
860
861 while(fn) {
862 if (FIB6_SUBTREE(fn) || fn->fn_flags & RTN_RTINFO) {
863 struct rt6key *key;
864
865 key = (struct rt6key *) ((u8 *) fn->leaf +
866 args->offset);
867
868 if (ipv6_prefix_equal(&key->addr, args->addr, key->plen)) {
869 #ifdef CONFIG_IPV6_SUBTREES
870 if (fn->subtree)
871 fn = fib6_lookup_1(fn->subtree, args + 1);
872 #endif
873 if (!fn || fn->fn_flags & RTN_RTINFO)
874 return fn;
875 }
876 }
877
878 if (fn->fn_flags & RTN_ROOT)
879 break;
880
881 fn = fn->parent;
882 }
883
884 return NULL;
885 }
886
887 struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr,
888 struct in6_addr *saddr)
889 {
890 struct fib6_node *fn;
891 struct lookup_args args[] = {
892 {
893 .offset = offsetof(struct rt6_info, rt6i_dst),
894 .addr = daddr,
895 },
896 #ifdef CONFIG_IPV6_SUBTREES
897 {
898 .offset = offsetof(struct rt6_info, rt6i_src),
899 .addr = saddr,
900 },
901 #endif
902 {
903 .offset = 0, /* sentinel */
904 }
905 };
906
907 fn = fib6_lookup_1(root, daddr ? args : args + 1);
908
909 if (fn == NULL || fn->fn_flags & RTN_TL_ROOT)
910 fn = root;
911
912 return fn;
913 }
914
915 /*
916 * Get node with specified destination prefix (and source prefix,
917 * if subtrees are used)
918 */
919
920
921 static struct fib6_node * fib6_locate_1(struct fib6_node *root,
922 struct in6_addr *addr,
923 int plen, int offset)
924 {
925 struct fib6_node *fn;
926
927 for (fn = root; fn ; ) {
928 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
929
930 /*
931 * Prefix match
932 */
933 if (plen < fn->fn_bit ||
934 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
935 return NULL;
936
937 if (plen == fn->fn_bit)
938 return fn;
939
940 /*
941 * We have more bits to go
942 */
943 if (addr_bit_set(addr, fn->fn_bit))
944 fn = fn->right;
945 else
946 fn = fn->left;
947 }
948 return NULL;
949 }
950
951 struct fib6_node * fib6_locate(struct fib6_node *root,
952 struct in6_addr *daddr, int dst_len,
953 struct in6_addr *saddr, int src_len)
954 {
955 struct fib6_node *fn;
956
957 fn = fib6_locate_1(root, daddr, dst_len,
958 offsetof(struct rt6_info, rt6i_dst));
959
960 #ifdef CONFIG_IPV6_SUBTREES
961 if (src_len) {
962 BUG_TRAP(saddr!=NULL);
963 if (fn && fn->subtree)
964 fn = fib6_locate_1(fn->subtree, saddr, src_len,
965 offsetof(struct rt6_info, rt6i_src));
966 }
967 #endif
968
969 if (fn && fn->fn_flags&RTN_RTINFO)
970 return fn;
971
972 return NULL;
973 }
974
975
976 /*
977 * Deletion
978 *
979 */
980
981 static struct rt6_info * fib6_find_prefix(struct fib6_node *fn)
982 {
983 if (fn->fn_flags&RTN_ROOT)
984 return &ip6_null_entry;
985
986 while(fn) {
987 if(fn->left)
988 return fn->left->leaf;
989
990 if(fn->right)
991 return fn->right->leaf;
992
993 fn = FIB6_SUBTREE(fn);
994 }
995 return NULL;
996 }
997
998 /*
999 * Called to trim the tree of intermediate nodes when possible. "fn"
1000 * is the node we want to try and remove.
1001 */
1002
1003 static struct fib6_node * fib6_repair_tree(struct fib6_node *fn)
1004 {
1005 int children;
1006 int nstate;
1007 struct fib6_node *child, *pn;
1008 struct fib6_walker_t *w;
1009 int iter = 0;
1010
1011 for (;;) {
1012 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
1013 iter++;
1014
1015 BUG_TRAP(!(fn->fn_flags&RTN_RTINFO));
1016 BUG_TRAP(!(fn->fn_flags&RTN_TL_ROOT));
1017 BUG_TRAP(fn->leaf==NULL);
1018
1019 children = 0;
1020 child = NULL;
1021 if (fn->right) child = fn->right, children |= 1;
1022 if (fn->left) child = fn->left, children |= 2;
1023
1024 if (children == 3 || FIB6_SUBTREE(fn)
1025 #ifdef CONFIG_IPV6_SUBTREES
1026 /* Subtree root (i.e. fn) may have one child */
1027 || (children && fn->fn_flags&RTN_ROOT)
1028 #endif
1029 ) {
1030 fn->leaf = fib6_find_prefix(fn);
1031 #if RT6_DEBUG >= 2
1032 if (fn->leaf==NULL) {
1033 BUG_TRAP(fn->leaf);
1034 fn->leaf = &ip6_null_entry;
1035 }
1036 #endif
1037 atomic_inc(&fn->leaf->rt6i_ref);
1038 return fn->parent;
1039 }
1040
1041 pn = fn->parent;
1042 #ifdef CONFIG_IPV6_SUBTREES
1043 if (FIB6_SUBTREE(pn) == fn) {
1044 BUG_TRAP(fn->fn_flags&RTN_ROOT);
1045 FIB6_SUBTREE(pn) = NULL;
1046 nstate = FWS_L;
1047 } else {
1048 BUG_TRAP(!(fn->fn_flags&RTN_ROOT));
1049 #endif
1050 if (pn->right == fn) pn->right = child;
1051 else if (pn->left == fn) pn->left = child;
1052 #if RT6_DEBUG >= 2
1053 else BUG_TRAP(0);
1054 #endif
1055 if (child)
1056 child->parent = pn;
1057 nstate = FWS_R;
1058 #ifdef CONFIG_IPV6_SUBTREES
1059 }
1060 #endif
1061
1062 read_lock(&fib6_walker_lock);
1063 FOR_WALKERS(w) {
1064 if (child == NULL) {
1065 if (w->root == fn) {
1066 w->root = w->node = NULL;
1067 RT6_TRACE("W %p adjusted by delroot 1\n", w);
1068 } else if (w->node == fn) {
1069 RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
1070 w->node = pn;
1071 w->state = nstate;
1072 }
1073 } else {
1074 if (w->root == fn) {
1075 w->root = child;
1076 RT6_TRACE("W %p adjusted by delroot 2\n", w);
1077 }
1078 if (w->node == fn) {
1079 w->node = child;
1080 if (children&2) {
1081 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1082 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
1083 } else {
1084 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
1085 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
1086 }
1087 }
1088 }
1089 }
1090 read_unlock(&fib6_walker_lock);
1091
1092 node_free(fn);
1093 if (pn->fn_flags&RTN_RTINFO || FIB6_SUBTREE(pn))
1094 return pn;
1095
1096 rt6_release(pn->leaf);
1097 pn->leaf = NULL;
1098 fn = pn;
1099 }
1100 }
1101
1102 static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
1103 struct nl_info *info)
1104 {
1105 struct fib6_walker_t *w;
1106 struct rt6_info *rt = *rtp;
1107
1108 RT6_TRACE("fib6_del_route\n");
1109
1110 /* Unlink it */
1111 *rtp = rt->u.dst.rt6_next;
1112 rt->rt6i_node = NULL;
1113 rt6_stats.fib_rt_entries--;
1114 rt6_stats.fib_discarded_routes++;
1115
1116 /* Reset round-robin state, if necessary */
1117 if (fn->rr_ptr == rt)
1118 fn->rr_ptr = NULL;
1119
1120 /* Adjust walkers */
1121 read_lock(&fib6_walker_lock);
1122 FOR_WALKERS(w) {
1123 if (w->state == FWS_C && w->leaf == rt) {
1124 RT6_TRACE("walker %p adjusted by delroute\n", w);
1125 w->leaf = rt->u.dst.rt6_next;
1126 if (w->leaf == NULL)
1127 w->state = FWS_U;
1128 }
1129 }
1130 read_unlock(&fib6_walker_lock);
1131
1132 rt->u.dst.rt6_next = NULL;
1133
1134 if (fn->leaf == NULL && fn->fn_flags&RTN_TL_ROOT)
1135 fn->leaf = &ip6_null_entry;
1136
1137 /* If it was last route, expunge its radix tree node */
1138 if (fn->leaf == NULL) {
1139 fn->fn_flags &= ~RTN_RTINFO;
1140 rt6_stats.fib_route_nodes--;
1141 fn = fib6_repair_tree(fn);
1142 }
1143
1144 if (atomic_read(&rt->rt6i_ref) != 1) {
1145 /* This route is used as dummy address holder in some split
1146 * nodes. It is not leaked, but it still holds other resources,
1147 * which must be released in time. So, scan ascendant nodes
1148 * and replace dummy references to this route with references
1149 * to still alive ones.
1150 */
1151 while (fn) {
1152 if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) {
1153 fn->leaf = fib6_find_prefix(fn);
1154 atomic_inc(&fn->leaf->rt6i_ref);
1155 rt6_release(rt);
1156 }
1157 fn = fn->parent;
1158 }
1159 /* No more references are possible at this point. */
1160 if (atomic_read(&rt->rt6i_ref) != 1) BUG();
1161 }
1162
1163 inet6_rt_notify(RTM_DELROUTE, rt, info);
1164 rt6_release(rt);
1165 }
1166
1167 int fib6_del(struct rt6_info *rt, struct nl_info *info)
1168 {
1169 struct fib6_node *fn = rt->rt6i_node;
1170 struct rt6_info **rtp;
1171
1172 #if RT6_DEBUG >= 2
1173 if (rt->u.dst.obsolete>0) {
1174 BUG_TRAP(fn==NULL);
1175 return -ENOENT;
1176 }
1177 #endif
1178 if (fn == NULL || rt == &ip6_null_entry)
1179 return -ENOENT;
1180
1181 BUG_TRAP(fn->fn_flags&RTN_RTINFO);
1182
1183 if (!(rt->rt6i_flags&RTF_CACHE)) {
1184 struct fib6_node *pn = fn;
1185 #ifdef CONFIG_IPV6_SUBTREES
1186 /* clones of this route might be in another subtree */
1187 if (rt->rt6i_src.plen) {
1188 while (!(pn->fn_flags&RTN_ROOT))
1189 pn = pn->parent;
1190 pn = pn->parent;
1191 }
1192 #endif
1193 fib6_prune_clones(pn, rt);
1194 }
1195
1196 /*
1197 * Walk the leaf entries looking for ourself
1198 */
1199
1200 for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.dst.rt6_next) {
1201 if (*rtp == rt) {
1202 fib6_del_route(fn, rtp, info);
1203 return 0;
1204 }
1205 }
1206 return -ENOENT;
1207 }
1208
1209 /*
1210 * Tree traversal function.
1211 *
1212 * Certainly, it is not interrupt safe.
1213 * However, it is internally reenterable wrt itself and fib6_add/fib6_del.
1214 * It means, that we can modify tree during walking
1215 * and use this function for garbage collection, clone pruning,
1216 * cleaning tree when a device goes down etc. etc.
1217 *
1218 * It guarantees that every node will be traversed,
1219 * and that it will be traversed only once.
1220 *
1221 * Callback function w->func may return:
1222 * 0 -> continue walking.
1223 * positive value -> walking is suspended (used by tree dumps,
1224 * and probably by gc, if it will be split to several slices)
1225 * negative value -> terminate walking.
1226 *
1227 * The function itself returns:
1228 * 0 -> walk is complete.
1229 * >0 -> walk is incomplete (i.e. suspended)
1230 * <0 -> walk is terminated by an error.
1231 */
1232
1233 static int fib6_walk_continue(struct fib6_walker_t *w)
1234 {
1235 struct fib6_node *fn, *pn;
1236
1237 for (;;) {
1238 fn = w->node;
1239 if (fn == NULL)
1240 return 0;
1241
1242 if (w->prune && fn != w->root &&
1243 fn->fn_flags&RTN_RTINFO && w->state < FWS_C) {
1244 w->state = FWS_C;
1245 w->leaf = fn->leaf;
1246 }
1247 switch (w->state) {
1248 #ifdef CONFIG_IPV6_SUBTREES
1249 case FWS_S:
1250 if (FIB6_SUBTREE(fn)) {
1251 w->node = FIB6_SUBTREE(fn);
1252 continue;
1253 }
1254 w->state = FWS_L;
1255 #endif
1256 case FWS_L:
1257 if (fn->left) {
1258 w->node = fn->left;
1259 w->state = FWS_INIT;
1260 continue;
1261 }
1262 w->state = FWS_R;
1263 case FWS_R:
1264 if (fn->right) {
1265 w->node = fn->right;
1266 w->state = FWS_INIT;
1267 continue;
1268 }
1269 w->state = FWS_C;
1270 w->leaf = fn->leaf;
1271 case FWS_C:
1272 if (w->leaf && fn->fn_flags&RTN_RTINFO) {
1273 int err = w->func(w);
1274 if (err)
1275 return err;
1276 continue;
1277 }
1278 w->state = FWS_U;
1279 case FWS_U:
1280 if (fn == w->root)
1281 return 0;
1282 pn = fn->parent;
1283 w->node = pn;
1284 #ifdef CONFIG_IPV6_SUBTREES
1285 if (FIB6_SUBTREE(pn) == fn) {
1286 BUG_TRAP(fn->fn_flags&RTN_ROOT);
1287 w->state = FWS_L;
1288 continue;
1289 }
1290 #endif
1291 if (pn->left == fn) {
1292 w->state = FWS_R;
1293 continue;
1294 }
1295 if (pn->right == fn) {
1296 w->state = FWS_C;
1297 w->leaf = w->node->leaf;
1298 continue;
1299 }
1300 #if RT6_DEBUG >= 2
1301 BUG_TRAP(0);
1302 #endif
1303 }
1304 }
1305 }
1306
1307 static int fib6_walk(struct fib6_walker_t *w)
1308 {
1309 int res;
1310
1311 w->state = FWS_INIT;
1312 w->node = w->root;
1313
1314 fib6_walker_link(w);
1315 res = fib6_walk_continue(w);
1316 if (res <= 0)
1317 fib6_walker_unlink(w);
1318 return res;
1319 }
1320
1321 static int fib6_clean_node(struct fib6_walker_t *w)
1322 {
1323 int res;
1324 struct rt6_info *rt;
1325 struct fib6_cleaner_t *c = (struct fib6_cleaner_t*)w;
1326
1327 for (rt = w->leaf; rt; rt = rt->u.dst.rt6_next) {
1328 res = c->func(rt, c->arg);
1329 if (res < 0) {
1330 w->leaf = rt;
1331 res = fib6_del(rt, NULL);
1332 if (res) {
1333 #if RT6_DEBUG >= 2
1334 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
1335 #endif
1336 continue;
1337 }
1338 return 0;
1339 }
1340 BUG_TRAP(res==0);
1341 }
1342 w->leaf = rt;
1343 return 0;
1344 }
1345
1346 /*
1347 * Convenient frontend to tree walker.
1348 *
1349 * func is called on each route.
1350 * It may return -1 -> delete this route.
1351 * 0 -> continue walking
1352 *
1353 * prune==1 -> only immediate children of node (certainly,
1354 * ignoring pure split nodes) will be scanned.
1355 */
1356
1357 static void fib6_clean_tree(struct fib6_node *root,
1358 int (*func)(struct rt6_info *, void *arg),
1359 int prune, void *arg)
1360 {
1361 struct fib6_cleaner_t c;
1362
1363 c.w.root = root;
1364 c.w.func = fib6_clean_node;
1365 c.w.prune = prune;
1366 c.func = func;
1367 c.arg = arg;
1368
1369 fib6_walk(&c.w);
1370 }
1371
1372 void fib6_clean_all(int (*func)(struct rt6_info *, void *arg),
1373 int prune, void *arg)
1374 {
1375 struct fib6_table *table;
1376 struct hlist_node *node;
1377 unsigned int h;
1378
1379 rcu_read_lock();
1380 for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
1381 hlist_for_each_entry_rcu(table, node, &fib_table_hash[h],
1382 tb6_hlist) {
1383 write_lock_bh(&table->tb6_lock);
1384 fib6_clean_tree(&table->tb6_root, func, prune, arg);
1385 write_unlock_bh(&table->tb6_lock);
1386 }
1387 }
1388 rcu_read_unlock();
1389 }
1390
1391 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1392 {
1393 if (rt->rt6i_flags & RTF_CACHE) {
1394 RT6_TRACE("pruning clone %p\n", rt);
1395 return -1;
1396 }
1397
1398 return 0;
1399 }
1400
1401 static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt)
1402 {
1403 fib6_clean_tree(fn, fib6_prune_clone, 1, rt);
1404 }
1405
1406 /*
1407 * Garbage collection
1408 */
1409
1410 static struct fib6_gc_args
1411 {
1412 int timeout;
1413 int more;
1414 } gc_args;
1415
1416 static int fib6_age(struct rt6_info *rt, void *arg)
1417 {
1418 unsigned long now = jiffies;
1419
1420 /*
1421 * check addrconf expiration here.
1422 * Routes are expired even if they are in use.
1423 *
1424 * Also age clones. Note, that clones are aged out
1425 * only if they are not in use now.
1426 */
1427
1428 if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {
1429 if (time_after(now, rt->rt6i_expires)) {
1430 RT6_TRACE("expiring %p\n", rt);
1431 return -1;
1432 }
1433 gc_args.more++;
1434 } else if (rt->rt6i_flags & RTF_CACHE) {
1435 if (atomic_read(&rt->u.dst.__refcnt) == 0 &&
1436 time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) {
1437 RT6_TRACE("aging clone %p\n", rt);
1438 return -1;
1439 } else if ((rt->rt6i_flags & RTF_GATEWAY) &&
1440 (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) {
1441 RT6_TRACE("purging route %p via non-router but gateway\n",
1442 rt);
1443 return -1;
1444 }
1445 gc_args.more++;
1446 }
1447
1448 return 0;
1449 }
1450
1451 static DEFINE_SPINLOCK(fib6_gc_lock);
1452
1453 void fib6_run_gc(unsigned long dummy)
1454 {
1455 if (dummy != ~0UL) {
1456 spin_lock_bh(&fib6_gc_lock);
1457 gc_args.timeout = dummy ? (int)dummy : ip6_rt_gc_interval;
1458 } else {
1459 local_bh_disable();
1460 if (!spin_trylock(&fib6_gc_lock)) {
1461 mod_timer(&ip6_fib_timer, jiffies + HZ);
1462 local_bh_enable();
1463 return;
1464 }
1465 gc_args.timeout = ip6_rt_gc_interval;
1466 }
1467 gc_args.more = 0;
1468
1469 ndisc_dst_gc(&gc_args.more);
1470 fib6_clean_all(fib6_age, 0, NULL);
1471
1472 if (gc_args.more)
1473 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
1474 else {
1475 del_timer(&ip6_fib_timer);
1476 ip6_fib_timer.expires = 0;
1477 }
1478 spin_unlock_bh(&fib6_gc_lock);
1479 }
1480
1481 void __init fib6_init(void)
1482 {
1483 fib6_node_kmem = kmem_cache_create("fib6_nodes",
1484 sizeof(struct fib6_node),
1485 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
1486 NULL, NULL);
1487
1488 fib6_tables_init();
1489 }
1490
1491 void fib6_gc_cleanup(void)
1492 {
1493 del_timer(&ip6_fib_timer);
1494 kmem_cache_destroy(fib6_node_kmem);
1495 }
Linux with added FPC-III support