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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
22#include <linux/config.h>
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
31#ifdef CONFIG_PROC_FS
32#include <linux/proc_fs.h>
33#endif
34
35#include <net/ipv6.h>
36#include <net/ndisc.h>
37#include <net/addrconf.h>
38
39#include <net/ip6_fib.h>
40#include <net/ip6_route.h>
41
42#define RT6_DEBUG 2
43
44#if RT6_DEBUG >= 3
45#define RT6_TRACE(x...) printk(KERN_DEBUG x)
46#else
47#define RT6_TRACE(x...) do { ; } while (0)
48#endif
49
50struct rt6_statistics rt6_stats;
51
Eric Dumazetba899662005-08-26 12:05:31 -070052static kmem_cache_t * fib6_node_kmem __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54enum fib_walk_state_t
55{
56#ifdef CONFIG_IPV6_SUBTREES
57 FWS_S,
58#endif
59 FWS_L,
60 FWS_R,
61 FWS_C,
62 FWS_U
63};
64
65struct fib6_cleaner_t
66{
67 struct fib6_walker_t w;
68 int (*func)(struct rt6_info *, void *arg);
69 void *arg;
70};
71
72DEFINE_RWLOCK(fib6_walker_lock);
73
74
75#ifdef CONFIG_IPV6_SUBTREES
76#define FWS_INIT FWS_S
77#define SUBTREE(fn) ((fn)->subtree)
78#else
79#define FWS_INIT FWS_L
80#define SUBTREE(fn) NULL
81#endif
82
83static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt);
84static struct fib6_node * fib6_repair_tree(struct fib6_node *fn);
85
86/*
87 * A routing update causes an increase of the serial number on the
88 * affected subtree. This allows for cached routes to be asynchronously
89 * tested when modifications are made to the destination cache as a
90 * result of redirects, path MTU changes, etc.
91 */
92
93static __u32 rt_sernum;
94
Ingo Molnar8d06afa2005-09-09 13:10:40 -070095static DEFINE_TIMER(ip6_fib_timer, fib6_run_gc, 0, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97struct fib6_walker_t fib6_walker_list = {
98 .prev = &fib6_walker_list,
99 .next = &fib6_walker_list,
100};
101
102#define FOR_WALKERS(w) for ((w)=fib6_walker_list.next; (w) != &fib6_walker_list; (w)=(w)->next)
103
104static __inline__ u32 fib6_new_sernum(void)
105{
106 u32 n = ++rt_sernum;
107 if ((__s32)n <= 0)
108 rt_sernum = n = 1;
109 return n;
110}
111
112/*
113 * Auxiliary address test functions for the radix tree.
114 *
115 * These assume a 32bit processor (although it will work on
116 * 64bit processors)
117 */
118
119/*
120 * test bit
121 */
122
123static __inline__ int addr_bit_set(void *token, int fn_bit)
124{
125 __u32 *addr = token;
126
127 return htonl(1 << ((~fn_bit)&0x1F)) & addr[fn_bit>>5];
128}
129
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130static __inline__ struct fib6_node * node_alloc(void)
131{
132 struct fib6_node *fn;
133
134 if ((fn = kmem_cache_alloc(fib6_node_kmem, SLAB_ATOMIC)) != NULL)
135 memset(fn, 0, sizeof(struct fib6_node));
136
137 return fn;
138}
139
140static __inline__ void node_free(struct fib6_node * fn)
141{
142 kmem_cache_free(fib6_node_kmem, fn);
143}
144
145static __inline__ void rt6_release(struct rt6_info *rt)
146{
147 if (atomic_dec_and_test(&rt->rt6i_ref))
148 dst_free(&rt->u.dst);
149}
150
151
152/*
153 * Routing Table
154 *
155 * return the appropriate node for a routing tree "add" operation
156 * by either creating and inserting or by returning an existing
157 * node.
158 */
159
160static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
161 int addrlen, int plen,
162 int offset)
163{
164 struct fib6_node *fn, *in, *ln;
165 struct fib6_node *pn = NULL;
166 struct rt6key *key;
167 int bit;
168 int dir = 0;
169 __u32 sernum = fib6_new_sernum();
170
171 RT6_TRACE("fib6_add_1\n");
172
173 /* insert node in tree */
174
175 fn = root;
176
177 do {
178 key = (struct rt6key *)((u8 *)fn->leaf + offset);
179
180 /*
181 * Prefix match
182 */
183 if (plen < fn->fn_bit ||
184 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
185 goto insert_above;
186
187 /*
188 * Exact match ?
189 */
190
191 if (plen == fn->fn_bit) {
192 /* clean up an intermediate node */
193 if ((fn->fn_flags & RTN_RTINFO) == 0) {
194 rt6_release(fn->leaf);
195 fn->leaf = NULL;
196 }
197
198 fn->fn_sernum = sernum;
199
200 return fn;
201 }
202
203 /*
204 * We have more bits to go
205 */
206
207 /* Try to walk down on tree. */
208 fn->fn_sernum = sernum;
209 dir = addr_bit_set(addr, fn->fn_bit);
210 pn = fn;
211 fn = dir ? fn->right: fn->left;
212 } while (fn);
213
214 /*
215 * We walked to the bottom of tree.
216 * Create new leaf node without children.
217 */
218
219 ln = node_alloc();
220
221 if (ln == NULL)
222 return NULL;
223 ln->fn_bit = plen;
224
225 ln->parent = pn;
226 ln->fn_sernum = sernum;
227
228 if (dir)
229 pn->right = ln;
230 else
231 pn->left = ln;
232
233 return ln;
234
235
236insert_above:
237 /*
238 * split since we don't have a common prefix anymore or
239 * we have a less significant route.
240 * we've to insert an intermediate node on the list
241 * this new node will point to the one we need to create
242 * and the current
243 */
244
245 pn = fn->parent;
246
247 /* find 1st bit in difference between the 2 addrs.
248
YOSHIFUJI Hideaki971f3592005-11-08 09:37:56 -0800249 See comment in __ipv6_addr_diff: bit may be an invalid value,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 but if it is >= plen, the value is ignored in any case.
251 */
252
YOSHIFUJI Hideaki971f3592005-11-08 09:37:56 -0800253 bit = __ipv6_addr_diff(addr, &key->addr, addrlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
255 /*
256 * (intermediate)[in]
257 * / \
258 * (new leaf node)[ln] (old node)[fn]
259 */
260 if (plen > bit) {
261 in = node_alloc();
262 ln = node_alloc();
263
264 if (in == NULL || ln == NULL) {
265 if (in)
266 node_free(in);
267 if (ln)
268 node_free(ln);
269 return NULL;
270 }
271
272 /*
273 * new intermediate node.
274 * RTN_RTINFO will
275 * be off since that an address that chooses one of
276 * the branches would not match less specific routes
277 * in the other branch
278 */
279
280 in->fn_bit = bit;
281
282 in->parent = pn;
283 in->leaf = fn->leaf;
284 atomic_inc(&in->leaf->rt6i_ref);
285
286 in->fn_sernum = sernum;
287
288 /* update parent pointer */
289 if (dir)
290 pn->right = in;
291 else
292 pn->left = in;
293
294 ln->fn_bit = plen;
295
296 ln->parent = in;
297 fn->parent = in;
298
299 ln->fn_sernum = sernum;
300
301 if (addr_bit_set(addr, bit)) {
302 in->right = ln;
303 in->left = fn;
304 } else {
305 in->left = ln;
306 in->right = fn;
307 }
308 } else { /* plen <= bit */
309
310 /*
311 * (new leaf node)[ln]
312 * / \
313 * (old node)[fn] NULL
314 */
315
316 ln = node_alloc();
317
318 if (ln == NULL)
319 return NULL;
320
321 ln->fn_bit = plen;
322
323 ln->parent = pn;
324
325 ln->fn_sernum = sernum;
326
327 if (dir)
328 pn->right = ln;
329 else
330 pn->left = ln;
331
332 if (addr_bit_set(&key->addr, plen))
333 ln->right = fn;
334 else
335 ln->left = fn;
336
337 fn->parent = ln;
338 }
339 return ln;
340}
341
342/*
343 * Insert routing information in a node.
344 */
345
346static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
Jamal Hadi Salim0d51aa82005-06-21 13:51:04 -0700347 struct nlmsghdr *nlh, struct netlink_skb_parms *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348{
349 struct rt6_info *iter = NULL;
350 struct rt6_info **ins;
351
352 ins = &fn->leaf;
353
354 if (fn->fn_flags&RTN_TL_ROOT &&
355 fn->leaf == &ip6_null_entry &&
356 !(rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ){
357 fn->leaf = rt;
358 rt->u.next = NULL;
359 goto out;
360 }
361
362 for (iter = fn->leaf; iter; iter=iter->u.next) {
363 /*
364 * Search for duplicates
365 */
366
367 if (iter->rt6i_metric == rt->rt6i_metric) {
368 /*
369 * Same priority level
370 */
371
372 if (iter->rt6i_dev == rt->rt6i_dev &&
373 iter->rt6i_idev == rt->rt6i_idev &&
374 ipv6_addr_equal(&iter->rt6i_gateway,
375 &rt->rt6i_gateway)) {
376 if (!(iter->rt6i_flags&RTF_EXPIRES))
377 return -EEXIST;
378 iter->rt6i_expires = rt->rt6i_expires;
379 if (!(rt->rt6i_flags&RTF_EXPIRES)) {
380 iter->rt6i_flags &= ~RTF_EXPIRES;
381 iter->rt6i_expires = 0;
382 }
383 return -EEXIST;
384 }
385 }
386
387 if (iter->rt6i_metric > rt->rt6i_metric)
388 break;
389
390 ins = &iter->u.next;
391 }
392
393 /*
394 * insert node
395 */
396
397out:
398 rt->u.next = iter;
399 *ins = rt;
400 rt->rt6i_node = fn;
401 atomic_inc(&rt->rt6i_ref);
Jamal Hadi Salim0d51aa82005-06-21 13:51:04 -0700402 inet6_rt_notify(RTM_NEWROUTE, rt, nlh, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 rt6_stats.fib_rt_entries++;
404
405 if ((fn->fn_flags & RTN_RTINFO) == 0) {
406 rt6_stats.fib_route_nodes++;
407 fn->fn_flags |= RTN_RTINFO;
408 }
409
410 return 0;
411}
412
413static __inline__ void fib6_start_gc(struct rt6_info *rt)
414{
415 if (ip6_fib_timer.expires == 0 &&
416 (rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE)))
417 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
418}
419
420void fib6_force_start_gc(void)
421{
422 if (ip6_fib_timer.expires == 0)
423 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
424}
425
426/*
427 * Add routing information to the routing tree.
428 * <destination addr>/<source addr>
429 * with source addr info in sub-trees
430 */
431
Jamal Hadi Salim0d51aa82005-06-21 13:51:04 -0700432int fib6_add(struct fib6_node *root, struct rt6_info *rt,
433 struct nlmsghdr *nlh, void *_rtattr, struct netlink_skb_parms *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434{
435 struct fib6_node *fn;
436 int err = -ENOMEM;
437
438 fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
439 rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst));
440
441 if (fn == NULL)
442 goto out;
443
444#ifdef CONFIG_IPV6_SUBTREES
445 if (rt->rt6i_src.plen) {
446 struct fib6_node *sn;
447
448 if (fn->subtree == NULL) {
449 struct fib6_node *sfn;
450
451 /*
452 * Create subtree.
453 *
454 * fn[main tree]
455 * |
456 * sfn[subtree root]
457 * \
458 * sn[new leaf node]
459 */
460
461 /* Create subtree root node */
462 sfn = node_alloc();
463 if (sfn == NULL)
464 goto st_failure;
465
466 sfn->leaf = &ip6_null_entry;
467 atomic_inc(&ip6_null_entry.rt6i_ref);
468 sfn->fn_flags = RTN_ROOT;
469 sfn->fn_sernum = fib6_new_sernum();
470
471 /* Now add the first leaf node to new subtree */
472
473 sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
474 sizeof(struct in6_addr), rt->rt6i_src.plen,
475 offsetof(struct rt6_info, rt6i_src));
476
477 if (sn == NULL) {
478 /* If it is failed, discard just allocated
479 root, and then (in st_failure) stale node
480 in main tree.
481 */
482 node_free(sfn);
483 goto st_failure;
484 }
485
486 /* Now link new subtree to main tree */
487 sfn->parent = fn;
488 fn->subtree = sfn;
489 if (fn->leaf == NULL) {
490 fn->leaf = rt;
491 atomic_inc(&rt->rt6i_ref);
492 }
493 } else {
494 sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
495 sizeof(struct in6_addr), rt->rt6i_src.plen,
496 offsetof(struct rt6_info, rt6i_src));
497
498 if (sn == NULL)
499 goto st_failure;
500 }
501
502 fn = sn;
503 }
504#endif
505
Jamal Hadi Salim0d51aa82005-06-21 13:51:04 -0700506 err = fib6_add_rt2node(fn, rt, nlh, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507
508 if (err == 0) {
509 fib6_start_gc(rt);
510 if (!(rt->rt6i_flags&RTF_CACHE))
511 fib6_prune_clones(fn, rt);
512 }
513
514out:
515 if (err)
516 dst_free(&rt->u.dst);
517 return err;
518
519#ifdef CONFIG_IPV6_SUBTREES
520 /* Subtree creation failed, probably main tree node
521 is orphan. If it is, shoot it.
522 */
523st_failure:
524 if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
525 fib6_repair_tree(fn);
526 dst_free(&rt->u.dst);
527 return err;
528#endif
529}
530
531/*
532 * Routing tree lookup
533 *
534 */
535
536struct lookup_args {
537 int offset; /* key offset on rt6_info */
538 struct in6_addr *addr; /* search key */
539};
540
541static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
542 struct lookup_args *args)
543{
544 struct fib6_node *fn;
545 int dir;
546
547 /*
548 * Descend on a tree
549 */
550
551 fn = root;
552
553 for (;;) {
554 struct fib6_node *next;
555
556 dir = addr_bit_set(args->addr, fn->fn_bit);
557
558 next = dir ? fn->right : fn->left;
559
560 if (next) {
561 fn = next;
562 continue;
563 }
564
565 break;
566 }
567
568 while ((fn->fn_flags & RTN_ROOT) == 0) {
569#ifdef CONFIG_IPV6_SUBTREES
570 if (fn->subtree) {
571 struct fib6_node *st;
572 struct lookup_args *narg;
573
574 narg = args + 1;
575
576 if (narg->addr) {
577 st = fib6_lookup_1(fn->subtree, narg);
578
579 if (st && !(st->fn_flags & RTN_ROOT))
580 return st;
581 }
582 }
583#endif
584
585 if (fn->fn_flags & RTN_RTINFO) {
586 struct rt6key *key;
587
588 key = (struct rt6key *) ((u8 *) fn->leaf +
589 args->offset);
590
591 if (ipv6_prefix_equal(&key->addr, args->addr, key->plen))
592 return fn;
593 }
594
595 fn = fn->parent;
596 }
597
598 return NULL;
599}
600
601struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr,
602 struct in6_addr *saddr)
603{
604 struct lookup_args args[2];
605 struct fib6_node *fn;
606
607 args[0].offset = offsetof(struct rt6_info, rt6i_dst);
608 args[0].addr = daddr;
609
610#ifdef CONFIG_IPV6_SUBTREES
611 args[1].offset = offsetof(struct rt6_info, rt6i_src);
612 args[1].addr = saddr;
613#endif
614
615 fn = fib6_lookup_1(root, args);
616
617 if (fn == NULL || fn->fn_flags & RTN_TL_ROOT)
618 fn = root;
619
620 return fn;
621}
622
623/*
624 * Get node with specified destination prefix (and source prefix,
625 * if subtrees are used)
626 */
627
628
629static struct fib6_node * fib6_locate_1(struct fib6_node *root,
630 struct in6_addr *addr,
631 int plen, int offset)
632{
633 struct fib6_node *fn;
634
635 for (fn = root; fn ; ) {
636 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
637
638 /*
639 * Prefix match
640 */
641 if (plen < fn->fn_bit ||
642 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
643 return NULL;
644
645 if (plen == fn->fn_bit)
646 return fn;
647
648 /*
649 * We have more bits to go
650 */
651 if (addr_bit_set(addr, fn->fn_bit))
652 fn = fn->right;
653 else
654 fn = fn->left;
655 }
656 return NULL;
657}
658
659struct fib6_node * fib6_locate(struct fib6_node *root,
660 struct in6_addr *daddr, int dst_len,
661 struct in6_addr *saddr, int src_len)
662{
663 struct fib6_node *fn;
664
665 fn = fib6_locate_1(root, daddr, dst_len,
666 offsetof(struct rt6_info, rt6i_dst));
667
668#ifdef CONFIG_IPV6_SUBTREES
669 if (src_len) {
670 BUG_TRAP(saddr!=NULL);
671 if (fn == NULL)
672 fn = fn->subtree;
673 if (fn)
674 fn = fib6_locate_1(fn, saddr, src_len,
675 offsetof(struct rt6_info, rt6i_src));
676 }
677#endif
678
679 if (fn && fn->fn_flags&RTN_RTINFO)
680 return fn;
681
682 return NULL;
683}
684
685
686/*
687 * Deletion
688 *
689 */
690
691static struct rt6_info * fib6_find_prefix(struct fib6_node *fn)
692{
693 if (fn->fn_flags&RTN_ROOT)
694 return &ip6_null_entry;
695
696 while(fn) {
697 if(fn->left)
698 return fn->left->leaf;
699
700 if(fn->right)
701 return fn->right->leaf;
702
703 fn = SUBTREE(fn);
704 }
705 return NULL;
706}
707
708/*
709 * Called to trim the tree of intermediate nodes when possible. "fn"
710 * is the node we want to try and remove.
711 */
712
713static struct fib6_node * fib6_repair_tree(struct fib6_node *fn)
714{
715 int children;
716 int nstate;
717 struct fib6_node *child, *pn;
718 struct fib6_walker_t *w;
719 int iter = 0;
720
721 for (;;) {
722 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
723 iter++;
724
725 BUG_TRAP(!(fn->fn_flags&RTN_RTINFO));
726 BUG_TRAP(!(fn->fn_flags&RTN_TL_ROOT));
727 BUG_TRAP(fn->leaf==NULL);
728
729 children = 0;
730 child = NULL;
731 if (fn->right) child = fn->right, children |= 1;
732 if (fn->left) child = fn->left, children |= 2;
733
734 if (children == 3 || SUBTREE(fn)
735#ifdef CONFIG_IPV6_SUBTREES
736 /* Subtree root (i.e. fn) may have one child */
737 || (children && fn->fn_flags&RTN_ROOT)
738#endif
739 ) {
740 fn->leaf = fib6_find_prefix(fn);
741#if RT6_DEBUG >= 2
742 if (fn->leaf==NULL) {
743 BUG_TRAP(fn->leaf);
744 fn->leaf = &ip6_null_entry;
745 }
746#endif
747 atomic_inc(&fn->leaf->rt6i_ref);
748 return fn->parent;
749 }
750
751 pn = fn->parent;
752#ifdef CONFIG_IPV6_SUBTREES
753 if (SUBTREE(pn) == fn) {
754 BUG_TRAP(fn->fn_flags&RTN_ROOT);
755 SUBTREE(pn) = NULL;
756 nstate = FWS_L;
757 } else {
758 BUG_TRAP(!(fn->fn_flags&RTN_ROOT));
759#endif
760 if (pn->right == fn) pn->right = child;
761 else if (pn->left == fn) pn->left = child;
762#if RT6_DEBUG >= 2
763 else BUG_TRAP(0);
764#endif
765 if (child)
766 child->parent = pn;
767 nstate = FWS_R;
768#ifdef CONFIG_IPV6_SUBTREES
769 }
770#endif
771
772 read_lock(&fib6_walker_lock);
773 FOR_WALKERS(w) {
774 if (child == NULL) {
775 if (w->root == fn) {
776 w->root = w->node = NULL;
777 RT6_TRACE("W %p adjusted by delroot 1\n", w);
778 } else if (w->node == fn) {
779 RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
780 w->node = pn;
781 w->state = nstate;
782 }
783 } else {
784 if (w->root == fn) {
785 w->root = child;
786 RT6_TRACE("W %p adjusted by delroot 2\n", w);
787 }
788 if (w->node == fn) {
789 w->node = child;
790 if (children&2) {
791 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
792 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
793 } else {
794 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
795 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
796 }
797 }
798 }
799 }
800 read_unlock(&fib6_walker_lock);
801
802 node_free(fn);
803 if (pn->fn_flags&RTN_RTINFO || SUBTREE(pn))
804 return pn;
805
806 rt6_release(pn->leaf);
807 pn->leaf = NULL;
808 fn = pn;
809 }
810}
811
812static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
Jamal Hadi Salim0d51aa82005-06-21 13:51:04 -0700813 struct nlmsghdr *nlh, void *_rtattr, struct netlink_skb_parms *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814{
815 struct fib6_walker_t *w;
816 struct rt6_info *rt = *rtp;
817
818 RT6_TRACE("fib6_del_route\n");
819
820 /* Unlink it */
821 *rtp = rt->u.next;
822 rt->rt6i_node = NULL;
823 rt6_stats.fib_rt_entries--;
824 rt6_stats.fib_discarded_routes++;
825
826 /* Adjust walkers */
827 read_lock(&fib6_walker_lock);
828 FOR_WALKERS(w) {
829 if (w->state == FWS_C && w->leaf == rt) {
830 RT6_TRACE("walker %p adjusted by delroute\n", w);
831 w->leaf = rt->u.next;
832 if (w->leaf == NULL)
833 w->state = FWS_U;
834 }
835 }
836 read_unlock(&fib6_walker_lock);
837
838 rt->u.next = NULL;
839
840 if (fn->leaf == NULL && fn->fn_flags&RTN_TL_ROOT)
841 fn->leaf = &ip6_null_entry;
842
843 /* If it was last route, expunge its radix tree node */
844 if (fn->leaf == NULL) {
845 fn->fn_flags &= ~RTN_RTINFO;
846 rt6_stats.fib_route_nodes--;
847 fn = fib6_repair_tree(fn);
848 }
849
850 if (atomic_read(&rt->rt6i_ref) != 1) {
851 /* This route is used as dummy address holder in some split
852 * nodes. It is not leaked, but it still holds other resources,
853 * which must be released in time. So, scan ascendant nodes
854 * and replace dummy references to this route with references
855 * to still alive ones.
856 */
857 while (fn) {
858 if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) {
859 fn->leaf = fib6_find_prefix(fn);
860 atomic_inc(&fn->leaf->rt6i_ref);
861 rt6_release(rt);
862 }
863 fn = fn->parent;
864 }
865 /* No more references are possible at this point. */
866 if (atomic_read(&rt->rt6i_ref) != 1) BUG();
867 }
868
Jamal Hadi Salim0d51aa82005-06-21 13:51:04 -0700869 inet6_rt_notify(RTM_DELROUTE, rt, nlh, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 rt6_release(rt);
871}
872
Jamal Hadi Salim0d51aa82005-06-21 13:51:04 -0700873int fib6_del(struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr, struct netlink_skb_parms *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874{
875 struct fib6_node *fn = rt->rt6i_node;
876 struct rt6_info **rtp;
877
878#if RT6_DEBUG >= 2
879 if (rt->u.dst.obsolete>0) {
880 BUG_TRAP(fn==NULL);
881 return -ENOENT;
882 }
883#endif
884 if (fn == NULL || rt == &ip6_null_entry)
885 return -ENOENT;
886
887 BUG_TRAP(fn->fn_flags&RTN_RTINFO);
888
889 if (!(rt->rt6i_flags&RTF_CACHE))
890 fib6_prune_clones(fn, rt);
891
892 /*
893 * Walk the leaf entries looking for ourself
894 */
895
896 for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.next) {
897 if (*rtp == rt) {
Jamal Hadi Salim0d51aa82005-06-21 13:51:04 -0700898 fib6_del_route(fn, rtp, nlh, _rtattr, req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 return 0;
900 }
901 }
902 return -ENOENT;
903}
904
905/*
906 * Tree traversal function.
907 *
908 * Certainly, it is not interrupt safe.
909 * However, it is internally reenterable wrt itself and fib6_add/fib6_del.
910 * It means, that we can modify tree during walking
911 * and use this function for garbage collection, clone pruning,
912 * cleaning tree when a device goes down etc. etc.
913 *
914 * It guarantees that every node will be traversed,
915 * and that it will be traversed only once.
916 *
917 * Callback function w->func may return:
918 * 0 -> continue walking.
919 * positive value -> walking is suspended (used by tree dumps,
920 * and probably by gc, if it will be split to several slices)
921 * negative value -> terminate walking.
922 *
923 * The function itself returns:
924 * 0 -> walk is complete.
925 * >0 -> walk is incomplete (i.e. suspended)
926 * <0 -> walk is terminated by an error.
927 */
928
929int fib6_walk_continue(struct fib6_walker_t *w)
930{
931 struct fib6_node *fn, *pn;
932
933 for (;;) {
934 fn = w->node;
935 if (fn == NULL)
936 return 0;
937
938 if (w->prune && fn != w->root &&
939 fn->fn_flags&RTN_RTINFO && w->state < FWS_C) {
940 w->state = FWS_C;
941 w->leaf = fn->leaf;
942 }
943 switch (w->state) {
944#ifdef CONFIG_IPV6_SUBTREES
945 case FWS_S:
946 if (SUBTREE(fn)) {
947 w->node = SUBTREE(fn);
948 continue;
949 }
950 w->state = FWS_L;
951#endif
952 case FWS_L:
953 if (fn->left) {
954 w->node = fn->left;
955 w->state = FWS_INIT;
956 continue;
957 }
958 w->state = FWS_R;
959 case FWS_R:
960 if (fn->right) {
961 w->node = fn->right;
962 w->state = FWS_INIT;
963 continue;
964 }
965 w->state = FWS_C;
966 w->leaf = fn->leaf;
967 case FWS_C:
968 if (w->leaf && fn->fn_flags&RTN_RTINFO) {
969 int err = w->func(w);
970 if (err)
971 return err;
972 continue;
973 }
974 w->state = FWS_U;
975 case FWS_U:
976 if (fn == w->root)
977 return 0;
978 pn = fn->parent;
979 w->node = pn;
980#ifdef CONFIG_IPV6_SUBTREES
981 if (SUBTREE(pn) == fn) {
982 BUG_TRAP(fn->fn_flags&RTN_ROOT);
983 w->state = FWS_L;
984 continue;
985 }
986#endif
987 if (pn->left == fn) {
988 w->state = FWS_R;
989 continue;
990 }
991 if (pn->right == fn) {
992 w->state = FWS_C;
993 w->leaf = w->node->leaf;
994 continue;
995 }
996#if RT6_DEBUG >= 2
997 BUG_TRAP(0);
998#endif
999 }
1000 }
1001}
1002
1003int fib6_walk(struct fib6_walker_t *w)
1004{
1005 int res;
1006
1007 w->state = FWS_INIT;
1008 w->node = w->root;
1009
1010 fib6_walker_link(w);
1011 res = fib6_walk_continue(w);
1012 if (res <= 0)
1013 fib6_walker_unlink(w);
1014 return res;
1015}
1016
1017static int fib6_clean_node(struct fib6_walker_t *w)
1018{
1019 int res;
1020 struct rt6_info *rt;
1021 struct fib6_cleaner_t *c = (struct fib6_cleaner_t*)w;
1022
1023 for (rt = w->leaf; rt; rt = rt->u.next) {
1024 res = c->func(rt, c->arg);
1025 if (res < 0) {
1026 w->leaf = rt;
Jamal Hadi Salim0d51aa82005-06-21 13:51:04 -07001027 res = fib6_del(rt, NULL, NULL, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028 if (res) {
1029#if RT6_DEBUG >= 2
1030 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
1031#endif
1032 continue;
1033 }
1034 return 0;
1035 }
1036 BUG_TRAP(res==0);
1037 }
1038 w->leaf = rt;
1039 return 0;
1040}
1041
1042/*
1043 * Convenient frontend to tree walker.
1044 *
1045 * func is called on each route.
1046 * It may return -1 -> delete this route.
1047 * 0 -> continue walking
1048 *
1049 * prune==1 -> only immediate children of node (certainly,
1050 * ignoring pure split nodes) will be scanned.
1051 */
1052
1053void fib6_clean_tree(struct fib6_node *root,
1054 int (*func)(struct rt6_info *, void *arg),
1055 int prune, void *arg)
1056{
1057 struct fib6_cleaner_t c;
1058
1059 c.w.root = root;
1060 c.w.func = fib6_clean_node;
1061 c.w.prune = prune;
1062 c.func = func;
1063 c.arg = arg;
1064
1065 fib6_walk(&c.w);
1066}
1067
1068static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1069{
1070 if (rt->rt6i_flags & RTF_CACHE) {
1071 RT6_TRACE("pruning clone %p\n", rt);
1072 return -1;
1073 }
1074
1075 return 0;
1076}
1077
1078static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt)
1079{
1080 fib6_clean_tree(fn, fib6_prune_clone, 1, rt);
1081}
1082
1083/*
1084 * Garbage collection
1085 */
1086
1087static struct fib6_gc_args
1088{
1089 int timeout;
1090 int more;
1091} gc_args;
1092
1093static int fib6_age(struct rt6_info *rt, void *arg)
1094{
1095 unsigned long now = jiffies;
1096
1097 /*
1098 * check addrconf expiration here.
1099 * Routes are expired even if they are in use.
1100 *
1101 * Also age clones. Note, that clones are aged out
1102 * only if they are not in use now.
1103 */
1104
1105 if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {
1106 if (time_after(now, rt->rt6i_expires)) {
1107 RT6_TRACE("expiring %p\n", rt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 return -1;
1109 }
1110 gc_args.more++;
1111 } else if (rt->rt6i_flags & RTF_CACHE) {
1112 if (atomic_read(&rt->u.dst.__refcnt) == 0 &&
1113 time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) {
1114 RT6_TRACE("aging clone %p\n", rt);
1115 return -1;
1116 } else if ((rt->rt6i_flags & RTF_GATEWAY) &&
1117 (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) {
1118 RT6_TRACE("purging route %p via non-router but gateway\n",
1119 rt);
1120 return -1;
1121 }
1122 gc_args.more++;
1123 }
1124
1125 return 0;
1126}
1127
1128static DEFINE_SPINLOCK(fib6_gc_lock);
1129
1130void fib6_run_gc(unsigned long dummy)
1131{
1132 if (dummy != ~0UL) {
1133 spin_lock_bh(&fib6_gc_lock);
1134 gc_args.timeout = dummy ? (int)dummy : ip6_rt_gc_interval;
1135 } else {
1136 local_bh_disable();
1137 if (!spin_trylock(&fib6_gc_lock)) {
1138 mod_timer(&ip6_fib_timer, jiffies + HZ);
1139 local_bh_enable();
1140 return;
1141 }
1142 gc_args.timeout = ip6_rt_gc_interval;
1143 }
1144 gc_args.more = 0;
1145
1146
1147 write_lock_bh(&rt6_lock);
1148 ndisc_dst_gc(&gc_args.more);
1149 fib6_clean_tree(&ip6_routing_table, fib6_age, 0, NULL);
1150 write_unlock_bh(&rt6_lock);
1151
1152 if (gc_args.more)
1153 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
1154 else {
1155 del_timer(&ip6_fib_timer);
1156 ip6_fib_timer.expires = 0;
1157 }
1158 spin_unlock_bh(&fib6_gc_lock);
1159}
1160
1161void __init fib6_init(void)
1162{
1163 fib6_node_kmem = kmem_cache_create("fib6_nodes",
1164 sizeof(struct fib6_node),
1165 0, SLAB_HWCACHE_ALIGN,
1166 NULL, NULL);
1167 if (!fib6_node_kmem)
1168 panic("cannot create fib6_nodes cache");
1169}
1170
1171void fib6_gc_cleanup(void)
1172{
1173 del_timer(&ip6_fib_timer);
1174 kmem_cache_destroy(fib6_node_kmem);
1175}