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-rw-r--r--net/ipv6/ip6_fib.c1225
1 files changed, 1225 insertions, 0 deletions
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
new file mode 100644
index 000000000000..405740b75abb
--- /dev/null
+++ b/net/ipv6/ip6_fib.c
@@ -0,0 +1,1225 @@
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 */
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
52static kmem_cache_t * fib6_node_kmem;
53
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
95static struct timer_list ip6_fib_timer = TIMER_INITIALIZER(fib6_run_gc, 0, 0);
96
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
130/*
131 * find the first different bit between two addresses
132 * length of address must be a multiple of 32bits
133 */
134
135static __inline__ int addr_diff(void *token1, void *token2, int addrlen)
136{
137 __u32 *a1 = token1;
138 __u32 *a2 = token2;
139 int i;
140
141 addrlen >>= 2;
142
143 for (i = 0; i < addrlen; i++) {
144 __u32 xb;
145
146 xb = a1[i] ^ a2[i];
147
148 if (xb) {
149 int j = 31;
150
151 xb = ntohl(xb);
152
153 while ((xb & (1 << j)) == 0)
154 j--;
155
156 return (i * 32 + 31 - j);
157 }
158 }
159
160 /*
161 * we should *never* get to this point since that
162 * would mean the addrs are equal
163 *
164 * However, we do get to it 8) And exacly, when
165 * addresses are equal 8)
166 *
167 * ip route add 1111::/128 via ...
168 * ip route add 1111::/64 via ...
169 * and we are here.
170 *
171 * Ideally, this function should stop comparison
172 * at prefix length. It does not, but it is still OK,
173 * if returned value is greater than prefix length.
174 * --ANK (980803)
175 */
176
177 return addrlen<<5;
178}
179
180static __inline__ struct fib6_node * node_alloc(void)
181{
182 struct fib6_node *fn;
183
184 if ((fn = kmem_cache_alloc(fib6_node_kmem, SLAB_ATOMIC)) != NULL)
185 memset(fn, 0, sizeof(struct fib6_node));
186
187 return fn;
188}
189
190static __inline__ void node_free(struct fib6_node * fn)
191{
192 kmem_cache_free(fib6_node_kmem, fn);
193}
194
195static __inline__ void rt6_release(struct rt6_info *rt)
196{
197 if (atomic_dec_and_test(&rt->rt6i_ref))
198 dst_free(&rt->u.dst);
199}
200
201
202/*
203 * Routing Table
204 *
205 * return the appropriate node for a routing tree "add" operation
206 * by either creating and inserting or by returning an existing
207 * node.
208 */
209
210static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr,
211 int addrlen, int plen,
212 int offset)
213{
214 struct fib6_node *fn, *in, *ln;
215 struct fib6_node *pn = NULL;
216 struct rt6key *key;
217 int bit;
218 int dir = 0;
219 __u32 sernum = fib6_new_sernum();
220
221 RT6_TRACE("fib6_add_1\n");
222
223 /* insert node in tree */
224
225 fn = root;
226
227 do {
228 key = (struct rt6key *)((u8 *)fn->leaf + offset);
229
230 /*
231 * Prefix match
232 */
233 if (plen < fn->fn_bit ||
234 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
235 goto insert_above;
236
237 /*
238 * Exact match ?
239 */
240
241 if (plen == fn->fn_bit) {
242 /* clean up an intermediate node */
243 if ((fn->fn_flags & RTN_RTINFO) == 0) {
244 rt6_release(fn->leaf);
245 fn->leaf = NULL;
246 }
247
248 fn->fn_sernum = sernum;
249
250 return fn;
251 }
252
253 /*
254 * We have more bits to go
255 */
256
257 /* Try to walk down on tree. */
258 fn->fn_sernum = sernum;
259 dir = addr_bit_set(addr, fn->fn_bit);
260 pn = fn;
261 fn = dir ? fn->right: fn->left;
262 } while (fn);
263
264 /*
265 * We walked to the bottom of tree.
266 * Create new leaf node without children.
267 */
268
269 ln = node_alloc();
270
271 if (ln == NULL)
272 return NULL;
273 ln->fn_bit = plen;
274
275 ln->parent = pn;
276 ln->fn_sernum = sernum;
277
278 if (dir)
279 pn->right = ln;
280 else
281 pn->left = ln;
282
283 return ln;
284
285
286insert_above:
287 /*
288 * split since we don't have a common prefix anymore or
289 * we have a less significant route.
290 * we've to insert an intermediate node on the list
291 * this new node will point to the one we need to create
292 * and the current
293 */
294
295 pn = fn->parent;
296
297 /* find 1st bit in difference between the 2 addrs.
298
299 See comment in addr_diff: bit may be an invalid value,
300 but if it is >= plen, the value is ignored in any case.
301 */
302
303 bit = addr_diff(addr, &key->addr, addrlen);
304
305 /*
306 * (intermediate)[in]
307 * / \
308 * (new leaf node)[ln] (old node)[fn]
309 */
310 if (plen > bit) {
311 in = node_alloc();
312 ln = node_alloc();
313
314 if (in == NULL || ln == NULL) {
315 if (in)
316 node_free(in);
317 if (ln)
318 node_free(ln);
319 return NULL;
320 }
321
322 /*
323 * new intermediate node.
324 * RTN_RTINFO will
325 * be off since that an address that chooses one of
326 * the branches would not match less specific routes
327 * in the other branch
328 */
329
330 in->fn_bit = bit;
331
332 in->parent = pn;
333 in->leaf = fn->leaf;
334 atomic_inc(&in->leaf->rt6i_ref);
335
336 in->fn_sernum = sernum;
337
338 /* update parent pointer */
339 if (dir)
340 pn->right = in;
341 else
342 pn->left = in;
343
344 ln->fn_bit = plen;
345
346 ln->parent = in;
347 fn->parent = in;
348
349 ln->fn_sernum = sernum;
350
351 if (addr_bit_set(addr, bit)) {
352 in->right = ln;
353 in->left = fn;
354 } else {
355 in->left = ln;
356 in->right = fn;
357 }
358 } else { /* plen <= bit */
359
360 /*
361 * (new leaf node)[ln]
362 * / \
363 * (old node)[fn] NULL
364 */
365
366 ln = node_alloc();
367
368 if (ln == NULL)
369 return NULL;
370
371 ln->fn_bit = plen;
372
373 ln->parent = pn;
374
375 ln->fn_sernum = sernum;
376
377 if (dir)
378 pn->right = ln;
379 else
380 pn->left = ln;
381
382 if (addr_bit_set(&key->addr, plen))
383 ln->right = fn;
384 else
385 ln->left = fn;
386
387 fn->parent = ln;
388 }
389 return ln;
390}
391
392/*
393 * Insert routing information in a node.
394 */
395
396static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
397 struct nlmsghdr *nlh)
398{
399 struct rt6_info *iter = NULL;
400 struct rt6_info **ins;
401
402 ins = &fn->leaf;
403
404 if (fn->fn_flags&RTN_TL_ROOT &&
405 fn->leaf == &ip6_null_entry &&
406 !(rt->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ){
407 fn->leaf = rt;
408 rt->u.next = NULL;
409 goto out;
410 }
411
412 for (iter = fn->leaf; iter; iter=iter->u.next) {
413 /*
414 * Search for duplicates
415 */
416
417 if (iter->rt6i_metric == rt->rt6i_metric) {
418 /*
419 * Same priority level
420 */
421
422 if (iter->rt6i_dev == rt->rt6i_dev &&
423 iter->rt6i_idev == rt->rt6i_idev &&
424 ipv6_addr_equal(&iter->rt6i_gateway,
425 &rt->rt6i_gateway)) {
426 if (!(iter->rt6i_flags&RTF_EXPIRES))
427 return -EEXIST;
428 iter->rt6i_expires = rt->rt6i_expires;
429 if (!(rt->rt6i_flags&RTF_EXPIRES)) {
430 iter->rt6i_flags &= ~RTF_EXPIRES;
431 iter->rt6i_expires = 0;
432 }
433 return -EEXIST;
434 }
435 }
436
437 if (iter->rt6i_metric > rt->rt6i_metric)
438 break;
439
440 ins = &iter->u.next;
441 }
442
443 /*
444 * insert node
445 */
446
447out:
448 rt->u.next = iter;
449 *ins = rt;
450 rt->rt6i_node = fn;
451 atomic_inc(&rt->rt6i_ref);
452 inet6_rt_notify(RTM_NEWROUTE, rt, nlh);
453 rt6_stats.fib_rt_entries++;
454
455 if ((fn->fn_flags & RTN_RTINFO) == 0) {
456 rt6_stats.fib_route_nodes++;
457 fn->fn_flags |= RTN_RTINFO;
458 }
459
460 return 0;
461}
462
463static __inline__ void fib6_start_gc(struct rt6_info *rt)
464{
465 if (ip6_fib_timer.expires == 0 &&
466 (rt->rt6i_flags & (RTF_EXPIRES|RTF_CACHE)))
467 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
468}
469
470void fib6_force_start_gc(void)
471{
472 if (ip6_fib_timer.expires == 0)
473 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
474}
475
476/*
477 * Add routing information to the routing tree.
478 * <destination addr>/<source addr>
479 * with source addr info in sub-trees
480 */
481
482int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr)
483{
484 struct fib6_node *fn;
485 int err = -ENOMEM;
486
487 fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
488 rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst));
489
490 if (fn == NULL)
491 goto out;
492
493#ifdef CONFIG_IPV6_SUBTREES
494 if (rt->rt6i_src.plen) {
495 struct fib6_node *sn;
496
497 if (fn->subtree == NULL) {
498 struct fib6_node *sfn;
499
500 /*
501 * Create subtree.
502 *
503 * fn[main tree]
504 * |
505 * sfn[subtree root]
506 * \
507 * sn[new leaf node]
508 */
509
510 /* Create subtree root node */
511 sfn = node_alloc();
512 if (sfn == NULL)
513 goto st_failure;
514
515 sfn->leaf = &ip6_null_entry;
516 atomic_inc(&ip6_null_entry.rt6i_ref);
517 sfn->fn_flags = RTN_ROOT;
518 sfn->fn_sernum = fib6_new_sernum();
519
520 /* Now add the first leaf node to new subtree */
521
522 sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
523 sizeof(struct in6_addr), rt->rt6i_src.plen,
524 offsetof(struct rt6_info, rt6i_src));
525
526 if (sn == NULL) {
527 /* If it is failed, discard just allocated
528 root, and then (in st_failure) stale node
529 in main tree.
530 */
531 node_free(sfn);
532 goto st_failure;
533 }
534
535 /* Now link new subtree to main tree */
536 sfn->parent = fn;
537 fn->subtree = sfn;
538 if (fn->leaf == NULL) {
539 fn->leaf = rt;
540 atomic_inc(&rt->rt6i_ref);
541 }
542 } else {
543 sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
544 sizeof(struct in6_addr), rt->rt6i_src.plen,
545 offsetof(struct rt6_info, rt6i_src));
546
547 if (sn == NULL)
548 goto st_failure;
549 }
550
551 fn = sn;
552 }
553#endif
554
555 err = fib6_add_rt2node(fn, rt, nlh);
556
557 if (err == 0) {
558 fib6_start_gc(rt);
559 if (!(rt->rt6i_flags&RTF_CACHE))
560 fib6_prune_clones(fn, rt);
561 }
562
563out:
564 if (err)
565 dst_free(&rt->u.dst);
566 return err;
567
568#ifdef CONFIG_IPV6_SUBTREES
569 /* Subtree creation failed, probably main tree node
570 is orphan. If it is, shoot it.
571 */
572st_failure:
573 if (fn && !(fn->fn_flags & (RTN_RTINFO|RTN_ROOT)))
574 fib6_repair_tree(fn);
575 dst_free(&rt->u.dst);
576 return err;
577#endif
578}
579
580/*
581 * Routing tree lookup
582 *
583 */
584
585struct lookup_args {
586 int offset; /* key offset on rt6_info */
587 struct in6_addr *addr; /* search key */
588};
589
590static struct fib6_node * fib6_lookup_1(struct fib6_node *root,
591 struct lookup_args *args)
592{
593 struct fib6_node *fn;
594 int dir;
595
596 /*
597 * Descend on a tree
598 */
599
600 fn = root;
601
602 for (;;) {
603 struct fib6_node *next;
604
605 dir = addr_bit_set(args->addr, fn->fn_bit);
606
607 next = dir ? fn->right : fn->left;
608
609 if (next) {
610 fn = next;
611 continue;
612 }
613
614 break;
615 }
616
617 while ((fn->fn_flags & RTN_ROOT) == 0) {
618#ifdef CONFIG_IPV6_SUBTREES
619 if (fn->subtree) {
620 struct fib6_node *st;
621 struct lookup_args *narg;
622
623 narg = args + 1;
624
625 if (narg->addr) {
626 st = fib6_lookup_1(fn->subtree, narg);
627
628 if (st && !(st->fn_flags & RTN_ROOT))
629 return st;
630 }
631 }
632#endif
633
634 if (fn->fn_flags & RTN_RTINFO) {
635 struct rt6key *key;
636
637 key = (struct rt6key *) ((u8 *) fn->leaf +
638 args->offset);
639
640 if (ipv6_prefix_equal(&key->addr, args->addr, key->plen))
641 return fn;
642 }
643
644 fn = fn->parent;
645 }
646
647 return NULL;
648}
649
650struct fib6_node * fib6_lookup(struct fib6_node *root, struct in6_addr *daddr,
651 struct in6_addr *saddr)
652{
653 struct lookup_args args[2];
654 struct fib6_node *fn;
655
656 args[0].offset = offsetof(struct rt6_info, rt6i_dst);
657 args[0].addr = daddr;
658
659#ifdef CONFIG_IPV6_SUBTREES
660 args[1].offset = offsetof(struct rt6_info, rt6i_src);
661 args[1].addr = saddr;
662#endif
663
664 fn = fib6_lookup_1(root, args);
665
666 if (fn == NULL || fn->fn_flags & RTN_TL_ROOT)
667 fn = root;
668
669 return fn;
670}
671
672/*
673 * Get node with specified destination prefix (and source prefix,
674 * if subtrees are used)
675 */
676
677
678static struct fib6_node * fib6_locate_1(struct fib6_node *root,
679 struct in6_addr *addr,
680 int plen, int offset)
681{
682 struct fib6_node *fn;
683
684 for (fn = root; fn ; ) {
685 struct rt6key *key = (struct rt6key *)((u8 *)fn->leaf + offset);
686
687 /*
688 * Prefix match
689 */
690 if (plen < fn->fn_bit ||
691 !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit))
692 return NULL;
693
694 if (plen == fn->fn_bit)
695 return fn;
696
697 /*
698 * We have more bits to go
699 */
700 if (addr_bit_set(addr, fn->fn_bit))
701 fn = fn->right;
702 else
703 fn = fn->left;
704 }
705 return NULL;
706}
707
708struct fib6_node * fib6_locate(struct fib6_node *root,
709 struct in6_addr *daddr, int dst_len,
710 struct in6_addr *saddr, int src_len)
711{
712 struct fib6_node *fn;
713
714 fn = fib6_locate_1(root, daddr, dst_len,
715 offsetof(struct rt6_info, rt6i_dst));
716
717#ifdef CONFIG_IPV6_SUBTREES
718 if (src_len) {
719 BUG_TRAP(saddr!=NULL);
720 if (fn == NULL)
721 fn = fn->subtree;
722 if (fn)
723 fn = fib6_locate_1(fn, saddr, src_len,
724 offsetof(struct rt6_info, rt6i_src));
725 }
726#endif
727
728 if (fn && fn->fn_flags&RTN_RTINFO)
729 return fn;
730
731 return NULL;
732}
733
734
735/*
736 * Deletion
737 *
738 */
739
740static struct rt6_info * fib6_find_prefix(struct fib6_node *fn)
741{
742 if (fn->fn_flags&RTN_ROOT)
743 return &ip6_null_entry;
744
745 while(fn) {
746 if(fn->left)
747 return fn->left->leaf;
748
749 if(fn->right)
750 return fn->right->leaf;
751
752 fn = SUBTREE(fn);
753 }
754 return NULL;
755}
756
757/*
758 * Called to trim the tree of intermediate nodes when possible. "fn"
759 * is the node we want to try and remove.
760 */
761
762static struct fib6_node * fib6_repair_tree(struct fib6_node *fn)
763{
764 int children;
765 int nstate;
766 struct fib6_node *child, *pn;
767 struct fib6_walker_t *w;
768 int iter = 0;
769
770 for (;;) {
771 RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
772 iter++;
773
774 BUG_TRAP(!(fn->fn_flags&RTN_RTINFO));
775 BUG_TRAP(!(fn->fn_flags&RTN_TL_ROOT));
776 BUG_TRAP(fn->leaf==NULL);
777
778 children = 0;
779 child = NULL;
780 if (fn->right) child = fn->right, children |= 1;
781 if (fn->left) child = fn->left, children |= 2;
782
783 if (children == 3 || SUBTREE(fn)
784#ifdef CONFIG_IPV6_SUBTREES
785 /* Subtree root (i.e. fn) may have one child */
786 || (children && fn->fn_flags&RTN_ROOT)
787#endif
788 ) {
789 fn->leaf = fib6_find_prefix(fn);
790#if RT6_DEBUG >= 2
791 if (fn->leaf==NULL) {
792 BUG_TRAP(fn->leaf);
793 fn->leaf = &ip6_null_entry;
794 }
795#endif
796 atomic_inc(&fn->leaf->rt6i_ref);
797 return fn->parent;
798 }
799
800 pn = fn->parent;
801#ifdef CONFIG_IPV6_SUBTREES
802 if (SUBTREE(pn) == fn) {
803 BUG_TRAP(fn->fn_flags&RTN_ROOT);
804 SUBTREE(pn) = NULL;
805 nstate = FWS_L;
806 } else {
807 BUG_TRAP(!(fn->fn_flags&RTN_ROOT));
808#endif
809 if (pn->right == fn) pn->right = child;
810 else if (pn->left == fn) pn->left = child;
811#if RT6_DEBUG >= 2
812 else BUG_TRAP(0);
813#endif
814 if (child)
815 child->parent = pn;
816 nstate = FWS_R;
817#ifdef CONFIG_IPV6_SUBTREES
818 }
819#endif
820
821 read_lock(&fib6_walker_lock);
822 FOR_WALKERS(w) {
823 if (child == NULL) {
824 if (w->root == fn) {
825 w->root = w->node = NULL;
826 RT6_TRACE("W %p adjusted by delroot 1\n", w);
827 } else if (w->node == fn) {
828 RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
829 w->node = pn;
830 w->state = nstate;
831 }
832 } else {
833 if (w->root == fn) {
834 w->root = child;
835 RT6_TRACE("W %p adjusted by delroot 2\n", w);
836 }
837 if (w->node == fn) {
838 w->node = child;
839 if (children&2) {
840 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
841 w->state = w->state>=FWS_R ? FWS_U : FWS_INIT;
842 } else {
843 RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
844 w->state = w->state>=FWS_C ? FWS_U : FWS_INIT;
845 }
846 }
847 }
848 }
849 read_unlock(&fib6_walker_lock);
850
851 node_free(fn);
852 if (pn->fn_flags&RTN_RTINFO || SUBTREE(pn))
853 return pn;
854
855 rt6_release(pn->leaf);
856 pn->leaf = NULL;
857 fn = pn;
858 }
859}
860
861static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
862 struct nlmsghdr *nlh, void *_rtattr)
863{
864 struct fib6_walker_t *w;
865 struct rt6_info *rt = *rtp;
866
867 RT6_TRACE("fib6_del_route\n");
868
869 /* Unlink it */
870 *rtp = rt->u.next;
871 rt->rt6i_node = NULL;
872 rt6_stats.fib_rt_entries--;
873 rt6_stats.fib_discarded_routes++;
874
875 /* Adjust walkers */
876 read_lock(&fib6_walker_lock);
877 FOR_WALKERS(w) {
878 if (w->state == FWS_C && w->leaf == rt) {
879 RT6_TRACE("walker %p adjusted by delroute\n", w);
880 w->leaf = rt->u.next;
881 if (w->leaf == NULL)
882 w->state = FWS_U;
883 }
884 }
885 read_unlock(&fib6_walker_lock);
886
887 rt->u.next = NULL;
888
889 if (fn->leaf == NULL && fn->fn_flags&RTN_TL_ROOT)
890 fn->leaf = &ip6_null_entry;
891
892 /* If it was last route, expunge its radix tree node */
893 if (fn->leaf == NULL) {
894 fn->fn_flags &= ~RTN_RTINFO;
895 rt6_stats.fib_route_nodes--;
896 fn = fib6_repair_tree(fn);
897 }
898
899 if (atomic_read(&rt->rt6i_ref) != 1) {
900 /* This route is used as dummy address holder in some split
901 * nodes. It is not leaked, but it still holds other resources,
902 * which must be released in time. So, scan ascendant nodes
903 * and replace dummy references to this route with references
904 * to still alive ones.
905 */
906 while (fn) {
907 if (!(fn->fn_flags&RTN_RTINFO) && fn->leaf == rt) {
908 fn->leaf = fib6_find_prefix(fn);
909 atomic_inc(&fn->leaf->rt6i_ref);
910 rt6_release(rt);
911 }
912 fn = fn->parent;
913 }
914 /* No more references are possible at this point. */
915 if (atomic_read(&rt->rt6i_ref) != 1) BUG();
916 }
917
918 inet6_rt_notify(RTM_DELROUTE, rt, nlh);
919 rt6_release(rt);
920}
921
922int fib6_del(struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr)
923{
924 struct fib6_node *fn = rt->rt6i_node;
925 struct rt6_info **rtp;
926
927#if RT6_DEBUG >= 2
928 if (rt->u.dst.obsolete>0) {
929 BUG_TRAP(fn==NULL);
930 return -ENOENT;
931 }
932#endif
933 if (fn == NULL || rt == &ip6_null_entry)
934 return -ENOENT;
935
936 BUG_TRAP(fn->fn_flags&RTN_RTINFO);
937
938 if (!(rt->rt6i_flags&RTF_CACHE))
939 fib6_prune_clones(fn, rt);
940
941 /*
942 * Walk the leaf entries looking for ourself
943 */
944
945 for (rtp = &fn->leaf; *rtp; rtp = &(*rtp)->u.next) {
946 if (*rtp == rt) {
947 fib6_del_route(fn, rtp, nlh, _rtattr);
948 return 0;
949 }
950 }
951 return -ENOENT;
952}
953
954/*
955 * Tree traversal function.
956 *
957 * Certainly, it is not interrupt safe.
958 * However, it is internally reenterable wrt itself and fib6_add/fib6_del.
959 * It means, that we can modify tree during walking
960 * and use this function for garbage collection, clone pruning,
961 * cleaning tree when a device goes down etc. etc.
962 *
963 * It guarantees that every node will be traversed,
964 * and that it will be traversed only once.
965 *
966 * Callback function w->func may return:
967 * 0 -> continue walking.
968 * positive value -> walking is suspended (used by tree dumps,
969 * and probably by gc, if it will be split to several slices)
970 * negative value -> terminate walking.
971 *
972 * The function itself returns:
973 * 0 -> walk is complete.
974 * >0 -> walk is incomplete (i.e. suspended)
975 * <0 -> walk is terminated by an error.
976 */
977
978int fib6_walk_continue(struct fib6_walker_t *w)
979{
980 struct fib6_node *fn, *pn;
981
982 for (;;) {
983 fn = w->node;
984 if (fn == NULL)
985 return 0;
986
987 if (w->prune && fn != w->root &&
988 fn->fn_flags&RTN_RTINFO && w->state < FWS_C) {
989 w->state = FWS_C;
990 w->leaf = fn->leaf;
991 }
992 switch (w->state) {
993#ifdef CONFIG_IPV6_SUBTREES
994 case FWS_S:
995 if (SUBTREE(fn)) {
996 w->node = SUBTREE(fn);
997 continue;
998 }
999 w->state = FWS_L;
1000#endif
1001 case FWS_L:
1002 if (fn->left) {
1003 w->node = fn->left;
1004 w->state = FWS_INIT;
1005 continue;
1006 }
1007 w->state = FWS_R;
1008 case FWS_R:
1009 if (fn->right) {
1010 w->node = fn->right;
1011 w->state = FWS_INIT;
1012 continue;
1013 }
1014 w->state = FWS_C;
1015 w->leaf = fn->leaf;
1016 case FWS_C:
1017 if (w->leaf && fn->fn_flags&RTN_RTINFO) {
1018 int err = w->func(w);
1019 if (err)
1020 return err;
1021 continue;
1022 }
1023 w->state = FWS_U;
1024 case FWS_U:
1025 if (fn == w->root)
1026 return 0;
1027 pn = fn->parent;
1028 w->node = pn;
1029#ifdef CONFIG_IPV6_SUBTREES
1030 if (SUBTREE(pn) == fn) {
1031 BUG_TRAP(fn->fn_flags&RTN_ROOT);
1032 w->state = FWS_L;
1033 continue;
1034 }
1035#endif
1036 if (pn->left == fn) {
1037 w->state = FWS_R;
1038 continue;
1039 }
1040 if (pn->right == fn) {
1041 w->state = FWS_C;
1042 w->leaf = w->node->leaf;
1043 continue;
1044 }
1045#if RT6_DEBUG >= 2
1046 BUG_TRAP(0);
1047#endif
1048 }
1049 }
1050}
1051
1052int fib6_walk(struct fib6_walker_t *w)
1053{
1054 int res;
1055
1056 w->state = FWS_INIT;
1057 w->node = w->root;
1058
1059 fib6_walker_link(w);
1060 res = fib6_walk_continue(w);
1061 if (res <= 0)
1062 fib6_walker_unlink(w);
1063 return res;
1064}
1065
1066static int fib6_clean_node(struct fib6_walker_t *w)
1067{
1068 int res;
1069 struct rt6_info *rt;
1070 struct fib6_cleaner_t *c = (struct fib6_cleaner_t*)w;
1071
1072 for (rt = w->leaf; rt; rt = rt->u.next) {
1073 res = c->func(rt, c->arg);
1074 if (res < 0) {
1075 w->leaf = rt;
1076 res = fib6_del(rt, NULL, NULL);
1077 if (res) {
1078#if RT6_DEBUG >= 2
1079 printk(KERN_DEBUG "fib6_clean_node: del failed: rt=%p@%p err=%d\n", rt, rt->rt6i_node, res);
1080#endif
1081 continue;
1082 }
1083 return 0;
1084 }
1085 BUG_TRAP(res==0);
1086 }
1087 w->leaf = rt;
1088 return 0;
1089}
1090
1091/*
1092 * Convenient frontend to tree walker.
1093 *
1094 * func is called on each route.
1095 * It may return -1 -> delete this route.
1096 * 0 -> continue walking
1097 *
1098 * prune==1 -> only immediate children of node (certainly,
1099 * ignoring pure split nodes) will be scanned.
1100 */
1101
1102void fib6_clean_tree(struct fib6_node *root,
1103 int (*func)(struct rt6_info *, void *arg),
1104 int prune, void *arg)
1105{
1106 struct fib6_cleaner_t c;
1107
1108 c.w.root = root;
1109 c.w.func = fib6_clean_node;
1110 c.w.prune = prune;
1111 c.func = func;
1112 c.arg = arg;
1113
1114 fib6_walk(&c.w);
1115}
1116
1117static int fib6_prune_clone(struct rt6_info *rt, void *arg)
1118{
1119 if (rt->rt6i_flags & RTF_CACHE) {
1120 RT6_TRACE("pruning clone %p\n", rt);
1121 return -1;
1122 }
1123
1124 return 0;
1125}
1126
1127static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt)
1128{
1129 fib6_clean_tree(fn, fib6_prune_clone, 1, rt);
1130}
1131
1132/*
1133 * Garbage collection
1134 */
1135
1136static struct fib6_gc_args
1137{
1138 int timeout;
1139 int more;
1140} gc_args;
1141
1142static int fib6_age(struct rt6_info *rt, void *arg)
1143{
1144 unsigned long now = jiffies;
1145
1146 /*
1147 * check addrconf expiration here.
1148 * Routes are expired even if they are in use.
1149 *
1150 * Also age clones. Note, that clones are aged out
1151 * only if they are not in use now.
1152 */
1153
1154 if (rt->rt6i_flags&RTF_EXPIRES && rt->rt6i_expires) {
1155 if (time_after(now, rt->rt6i_expires)) {
1156 RT6_TRACE("expiring %p\n", rt);
1157 rt6_reset_dflt_pointer(rt);
1158 return -1;
1159 }
1160 gc_args.more++;
1161 } else if (rt->rt6i_flags & RTF_CACHE) {
1162 if (atomic_read(&rt->u.dst.__refcnt) == 0 &&
1163 time_after_eq(now, rt->u.dst.lastuse + gc_args.timeout)) {
1164 RT6_TRACE("aging clone %p\n", rt);
1165 return -1;
1166 } else if ((rt->rt6i_flags & RTF_GATEWAY) &&
1167 (!(rt->rt6i_nexthop->flags & NTF_ROUTER))) {
1168 RT6_TRACE("purging route %p via non-router but gateway\n",
1169 rt);
1170 return -1;
1171 }
1172 gc_args.more++;
1173 }
1174
1175 return 0;
1176}
1177
1178static DEFINE_SPINLOCK(fib6_gc_lock);
1179
1180void fib6_run_gc(unsigned long dummy)
1181{
1182 if (dummy != ~0UL) {
1183 spin_lock_bh(&fib6_gc_lock);
1184 gc_args.timeout = dummy ? (int)dummy : ip6_rt_gc_interval;
1185 } else {
1186 local_bh_disable();
1187 if (!spin_trylock(&fib6_gc_lock)) {
1188 mod_timer(&ip6_fib_timer, jiffies + HZ);
1189 local_bh_enable();
1190 return;
1191 }
1192 gc_args.timeout = ip6_rt_gc_interval;
1193 }
1194 gc_args.more = 0;
1195
1196
1197 write_lock_bh(&rt6_lock);
1198 ndisc_dst_gc(&gc_args.more);
1199 fib6_clean_tree(&ip6_routing_table, fib6_age, 0, NULL);
1200 write_unlock_bh(&rt6_lock);
1201
1202 if (gc_args.more)
1203 mod_timer(&ip6_fib_timer, jiffies + ip6_rt_gc_interval);
1204 else {
1205 del_timer(&ip6_fib_timer);
1206 ip6_fib_timer.expires = 0;
1207 }
1208 spin_unlock_bh(&fib6_gc_lock);
1209}
1210
1211void __init fib6_init(void)
1212{
1213 fib6_node_kmem = kmem_cache_create("fib6_nodes",
1214 sizeof(struct fib6_node),
1215 0, SLAB_HWCACHE_ALIGN,
1216 NULL, NULL);
1217 if (!fib6_node_kmem)
1218 panic("cannot create fib6_nodes cache");
1219}
1220
1221void fib6_gc_cleanup(void)
1222{
1223 del_timer(&ip6_fib_timer);
1224 kmem_cache_destroy(fib6_node_kmem);
1225}
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-29 13:31:20 -0500