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1da177e4 LT |
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 | ||
50 | struct rt6_statistics rt6_stats; | |
51 | ||
52 | static kmem_cache_t * fib6_node_kmem; | |
53 | ||
54 | enum 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 | ||
65 | struct fib6_cleaner_t | |
66 | { | |
67 | struct fib6_walker_t w; | |
68 | int (*func)(struct rt6_info *, void *arg); | |
69 | void *arg; | |
70 | }; | |
71 | ||
72 | DEFINE_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 | ||
83 | static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt); | |
84 | static 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 | ||
93 | static __u32 rt_sernum; | |
94 | ||
95 | static struct timer_list ip6_fib_timer = TIMER_INITIALIZER(fib6_run_gc, 0, 0); | |
96 | ||
97 | struct 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 | ||
104 | static __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 | ||
123 | static __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 | ||
135 | static __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 | ||
180 | static __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 | ||
190 | static __inline__ void node_free(struct fib6_node * fn) | |
191 | { | |
192 | kmem_cache_free(fib6_node_kmem, fn); | |
193 | } | |
194 | ||
195 | static __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 | ||
210 | static 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 | ||
286 | insert_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 | ||
396 | static 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 | ||
447 | out: | |
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 | ||
463 | static __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 | ||
470 | void 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 | ||
482 | int 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 | ||
563 | out: | |
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 | */ | |
572 | st_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 | ||
585 | struct lookup_args { | |
586 | int offset; /* key offset on rt6_info */ | |
587 | struct in6_addr *addr; /* search key */ | |
588 | }; | |
589 | ||
590 | static 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 | ||
650 | struct 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 | ||
678 | static 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 | ||
708 | struct 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 | ||
740 | static 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 | ||
762 | static 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 | ||
861 | static 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 | ||
922 | int 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 | ||
978 | int 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 | ||
1052 | int 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 | ||
1066 | static 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 | ||
1102 | void 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 | ||
1117 | static 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 | ||
1127 | static 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 | ||
1136 | static struct fib6_gc_args | |
1137 | { | |
1138 | int timeout; | |
1139 | int more; | |
1140 | } gc_args; | |
1141 | ||
1142 | static 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 | ||
1178 | static DEFINE_SPINLOCK(fib6_gc_lock); | |
1179 | ||
1180 | void 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 | ||
1211 | void __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 | ||
1221 | void fib6_gc_cleanup(void) | |
1222 | { | |
1223 | del_timer(&ip6_fib_timer); | |
1224 | kmem_cache_destroy(fib6_node_kmem); | |
1225 | } |