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Remove all #inclusions of asm/system.h
[linux-2.6.git] / net / ipv4 / fib_semantics.c
blob5063fa38ac7becd71bf0eea737e596f9567b48a5
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * IPv4 Forwarding Information Base: semantics.
7 *
8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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 #include <asm/uaccess.h>
17 #include <linux/bitops.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/jiffies.h>
21 #include <linux/mm.h>
22 #include <linux/string.h>
23 #include <linux/socket.h>
24 #include <linux/sockios.h>
25 #include <linux/errno.h>
26 #include <linux/in.h>
27 #include <linux/inet.h>
28 #include <linux/inetdevice.h>
29 #include <linux/netdevice.h>
30 #include <linux/if_arp.h>
31 #include <linux/proc_fs.h>
32 #include <linux/skbuff.h>
33 #include <linux/init.h>
34 #include <linux/slab.h>
35
36 #include <net/arp.h>
37 #include <net/ip.h>
38 #include <net/protocol.h>
39 #include <net/route.h>
40 #include <net/tcp.h>
41 #include <net/sock.h>
42 #include <net/ip_fib.h>
43 #include <net/netlink.h>
44 #include <net/nexthop.h>
45
46 #include "fib_lookup.h"
47
48 static DEFINE_SPINLOCK(fib_info_lock);
49 static struct hlist_head *fib_info_hash;
50 static struct hlist_head *fib_info_laddrhash;
51 static unsigned int fib_info_hash_size;
52 static unsigned int fib_info_cnt;
53
54 #define DEVINDEX_HASHBITS 8
55 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
56 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
57
58 #ifdef CONFIG_IP_ROUTE_MULTIPATH
59
60 static DEFINE_SPINLOCK(fib_multipath_lock);
61
62 #define for_nexthops(fi) { \
63 int nhsel; const struct fib_nh *nh; \
64 for (nhsel = 0, nh = (fi)->fib_nh; \
65 nhsel < (fi)->fib_nhs; \
66 nh++, nhsel++)
67
68 #define change_nexthops(fi) { \
69 int nhsel; struct fib_nh *nexthop_nh; \
70 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
71 nhsel < (fi)->fib_nhs; \
72 nexthop_nh++, nhsel++)
73
74 #else /* CONFIG_IP_ROUTE_MULTIPATH */
75
76 /* Hope, that gcc will optimize it to get rid of dummy loop */
77
78 #define for_nexthops(fi) { \
79 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
80 for (nhsel = 0; nhsel < 1; nhsel++)
81
82 #define change_nexthops(fi) { \
83 int nhsel; \
84 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
88
89 #define endfor_nexthops(fi) }
90
91
92 const struct fib_prop fib_props[RTN_MAX + 1] = {
93 [RTN_UNSPEC] = {
94 .error = 0,
95 .scope = RT_SCOPE_NOWHERE,
96 },
97 [RTN_UNICAST] = {
98 .error = 0,
99 .scope = RT_SCOPE_UNIVERSE,
100 },
101 [RTN_LOCAL] = {
102 .error = 0,
103 .scope = RT_SCOPE_HOST,
104 },
105 [RTN_BROADCAST] = {
106 .error = 0,
107 .scope = RT_SCOPE_LINK,
108 },
109 [RTN_ANYCAST] = {
110 .error = 0,
111 .scope = RT_SCOPE_LINK,
112 },
113 [RTN_MULTICAST] = {
114 .error = 0,
115 .scope = RT_SCOPE_UNIVERSE,
116 },
117 [RTN_BLACKHOLE] = {
118 .error = -EINVAL,
119 .scope = RT_SCOPE_UNIVERSE,
120 },
121 [RTN_UNREACHABLE] = {
122 .error = -EHOSTUNREACH,
123 .scope = RT_SCOPE_UNIVERSE,
124 },
125 [RTN_PROHIBIT] = {
126 .error = -EACCES,
127 .scope = RT_SCOPE_UNIVERSE,
128 },
129 [RTN_THROW] = {
130 .error = -EAGAIN,
131 .scope = RT_SCOPE_UNIVERSE,
132 },
133 [RTN_NAT] = {
134 .error = -EINVAL,
135 .scope = RT_SCOPE_NOWHERE,
136 },
137 [RTN_XRESOLVE] = {
138 .error = -EINVAL,
139 .scope = RT_SCOPE_NOWHERE,
140 },
141 };
142
143 /* Release a nexthop info record */
144 static void free_fib_info_rcu(struct rcu_head *head)
145 {
146 struct fib_info *fi = container_of(head, struct fib_info, rcu);
147
148 if (fi->fib_metrics != (u32 *) dst_default_metrics)
149 kfree(fi->fib_metrics);
150 kfree(fi);
151 }
152
153 void free_fib_info(struct fib_info *fi)
154 {
155 if (fi->fib_dead == 0) {
156 pr_warn("Freeing alive fib_info %p\n", fi);
157 return;
158 }
159 change_nexthops(fi) {
160 if (nexthop_nh->nh_dev)
161 dev_put(nexthop_nh->nh_dev);
162 nexthop_nh->nh_dev = NULL;
163 } endfor_nexthops(fi);
164 fib_info_cnt--;
165 release_net(fi->fib_net);
166 call_rcu(&fi->rcu, free_fib_info_rcu);
167 }
168
169 void fib_release_info(struct fib_info *fi)
170 {
171 spin_lock_bh(&fib_info_lock);
172 if (fi && --fi->fib_treeref == 0) {
173 hlist_del(&fi->fib_hash);
174 if (fi->fib_prefsrc)
175 hlist_del(&fi->fib_lhash);
176 change_nexthops(fi) {
177 if (!nexthop_nh->nh_dev)
178 continue;
179 hlist_del(&nexthop_nh->nh_hash);
180 } endfor_nexthops(fi)
181 fi->fib_dead = 1;
182 fib_info_put(fi);
183 }
184 spin_unlock_bh(&fib_info_lock);
185 }
186
187 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
188 {
189 const struct fib_nh *onh = ofi->fib_nh;
190
191 for_nexthops(fi) {
192 if (nh->nh_oif != onh->nh_oif ||
193 nh->nh_gw != onh->nh_gw ||
194 nh->nh_scope != onh->nh_scope ||
195 #ifdef CONFIG_IP_ROUTE_MULTIPATH
196 nh->nh_weight != onh->nh_weight ||
197 #endif
198 #ifdef CONFIG_IP_ROUTE_CLASSID
199 nh->nh_tclassid != onh->nh_tclassid ||
200 #endif
201 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
202 return -1;
203 onh++;
204 } endfor_nexthops(fi);
205 return 0;
206 }
207
208 static inline unsigned int fib_devindex_hashfn(unsigned int val)
209 {
210 unsigned int mask = DEVINDEX_HASHSIZE - 1;
211
212 return (val ^
213 (val >> DEVINDEX_HASHBITS) ^
214 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
215 }
216
217 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
218 {
219 unsigned int mask = (fib_info_hash_size - 1);
220 unsigned int val = fi->fib_nhs;
221
222 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
223 val ^= (__force u32)fi->fib_prefsrc;
224 val ^= fi->fib_priority;
225 for_nexthops(fi) {
226 val ^= fib_devindex_hashfn(nh->nh_oif);
227 } endfor_nexthops(fi)
228
229 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
230 }
231
232 static struct fib_info *fib_find_info(const struct fib_info *nfi)
233 {
234 struct hlist_head *head;
235 struct hlist_node *node;
236 struct fib_info *fi;
237 unsigned int hash;
238
239 hash = fib_info_hashfn(nfi);
240 head = &fib_info_hash[hash];
241
242 hlist_for_each_entry(fi, node, head, fib_hash) {
243 if (!net_eq(fi->fib_net, nfi->fib_net))
244 continue;
245 if (fi->fib_nhs != nfi->fib_nhs)
246 continue;
247 if (nfi->fib_protocol == fi->fib_protocol &&
248 nfi->fib_scope == fi->fib_scope &&
249 nfi->fib_prefsrc == fi->fib_prefsrc &&
250 nfi->fib_priority == fi->fib_priority &&
251 memcmp(nfi->fib_metrics, fi->fib_metrics,
252 sizeof(u32) * RTAX_MAX) == 0 &&
253 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
254 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
255 return fi;
256 }
257
258 return NULL;
259 }
260
261 /* Check, that the gateway is already configured.
262 * Used only by redirect accept routine.
263 */
264 int ip_fib_check_default(__be32 gw, struct net_device *dev)
265 {
266 struct hlist_head *head;
267 struct hlist_node *node;
268 struct fib_nh *nh;
269 unsigned int hash;
270
271 spin_lock(&fib_info_lock);
272
273 hash = fib_devindex_hashfn(dev->ifindex);
274 head = &fib_info_devhash[hash];
275 hlist_for_each_entry(nh, node, head, nh_hash) {
276 if (nh->nh_dev == dev &&
277 nh->nh_gw == gw &&
278 !(nh->nh_flags & RTNH_F_DEAD)) {
279 spin_unlock(&fib_info_lock);
280 return 0;
281 }
282 }
283
284 spin_unlock(&fib_info_lock);
285
286 return -1;
287 }
288
289 static inline size_t fib_nlmsg_size(struct fib_info *fi)
290 {
291 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
292 + nla_total_size(4) /* RTA_TABLE */
293 + nla_total_size(4) /* RTA_DST */
294 + nla_total_size(4) /* RTA_PRIORITY */
295 + nla_total_size(4); /* RTA_PREFSRC */
296
297 /* space for nested metrics */
298 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
299
300 if (fi->fib_nhs) {
301 /* Also handles the special case fib_nhs == 1 */
302
303 /* each nexthop is packed in an attribute */
304 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
305
306 /* may contain flow and gateway attribute */
307 nhsize += 2 * nla_total_size(4);
308
309 /* all nexthops are packed in a nested attribute */
310 payload += nla_total_size(fi->fib_nhs * nhsize);
311 }
312
313 return payload;
314 }
315
316 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
317 int dst_len, u32 tb_id, struct nl_info *info,
318 unsigned int nlm_flags)
319 {
320 struct sk_buff *skb;
321 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
322 int err = -ENOBUFS;
323
324 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
325 if (skb == NULL)
326 goto errout;
327
328 err = fib_dump_info(skb, info->pid, seq, event, tb_id,
329 fa->fa_type, key, dst_len,
330 fa->fa_tos, fa->fa_info, nlm_flags);
331 if (err < 0) {
332 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
333 WARN_ON(err == -EMSGSIZE);
334 kfree_skb(skb);
335 goto errout;
336 }
337 rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
338 info->nlh, GFP_KERNEL);
339 return;
340 errout:
341 if (err < 0)
342 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
343 }
344
345 /* Return the first fib alias matching TOS with
346 * priority less than or equal to PRIO.
347 */
348 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
349 {
350 if (fah) {
351 struct fib_alias *fa;
352 list_for_each_entry(fa, fah, fa_list) {
353 if (fa->fa_tos > tos)
354 continue;
355 if (fa->fa_info->fib_priority >= prio ||
356 fa->fa_tos < tos)
357 return fa;
358 }
359 }
360 return NULL;
361 }
362
363 int fib_detect_death(struct fib_info *fi, int order,
364 struct fib_info **last_resort, int *last_idx, int dflt)
365 {
366 struct neighbour *n;
367 int state = NUD_NONE;
368
369 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
370 if (n) {
371 state = n->nud_state;
372 neigh_release(n);
373 }
374 if (state == NUD_REACHABLE)
375 return 0;
376 if ((state & NUD_VALID) && order != dflt)
377 return 0;
378 if ((state & NUD_VALID) ||
379 (*last_idx < 0 && order > dflt)) {
380 *last_resort = fi;
381 *last_idx = order;
382 }
383 return 1;
384 }
385
386 #ifdef CONFIG_IP_ROUTE_MULTIPATH
387
388 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
389 {
390 int nhs = 0;
391
392 while (rtnh_ok(rtnh, remaining)) {
393 nhs++;
394 rtnh = rtnh_next(rtnh, &remaining);
395 }
396
397 /* leftover implies invalid nexthop configuration, discard it */
398 return remaining > 0 ? 0 : nhs;
399 }
400
401 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
402 int remaining, struct fib_config *cfg)
403 {
404 change_nexthops(fi) {
405 int attrlen;
406
407 if (!rtnh_ok(rtnh, remaining))
408 return -EINVAL;
409
410 nexthop_nh->nh_flags =
411 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
412 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
413 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
414
415 attrlen = rtnh_attrlen(rtnh);
416 if (attrlen > 0) {
417 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
418
419 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
420 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
421 #ifdef CONFIG_IP_ROUTE_CLASSID
422 nla = nla_find(attrs, attrlen, RTA_FLOW);
423 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
424 #endif
425 }
426
427 rtnh = rtnh_next(rtnh, &remaining);
428 } endfor_nexthops(fi);
429
430 return 0;
431 }
432
433 #endif
434
435 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
436 {
437 #ifdef CONFIG_IP_ROUTE_MULTIPATH
438 struct rtnexthop *rtnh;
439 int remaining;
440 #endif
441
442 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
443 return 1;
444
445 if (cfg->fc_oif || cfg->fc_gw) {
446 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
447 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
448 return 0;
449 return 1;
450 }
451
452 #ifdef CONFIG_IP_ROUTE_MULTIPATH
453 if (cfg->fc_mp == NULL)
454 return 0;
455
456 rtnh = cfg->fc_mp;
457 remaining = cfg->fc_mp_len;
458
459 for_nexthops(fi) {
460 int attrlen;
461
462 if (!rtnh_ok(rtnh, remaining))
463 return -EINVAL;
464
465 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
466 return 1;
467
468 attrlen = rtnh_attrlen(rtnh);
469 if (attrlen < 0) {
470 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
471
472 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
473 if (nla && nla_get_be32(nla) != nh->nh_gw)
474 return 1;
475 #ifdef CONFIG_IP_ROUTE_CLASSID
476 nla = nla_find(attrs, attrlen, RTA_FLOW);
477 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
478 return 1;
479 #endif
480 }
481
482 rtnh = rtnh_next(rtnh, &remaining);
483 } endfor_nexthops(fi);
484 #endif
485 return 0;
486 }
487
488
489 /*
490 * Picture
491 * -------
492 *
493 * Semantics of nexthop is very messy by historical reasons.
494 * We have to take into account, that:
495 * a) gateway can be actually local interface address,
496 * so that gatewayed route is direct.
497 * b) gateway must be on-link address, possibly
498 * described not by an ifaddr, but also by a direct route.
499 * c) If both gateway and interface are specified, they should not
500 * contradict.
501 * d) If we use tunnel routes, gateway could be not on-link.
502 *
503 * Attempt to reconcile all of these (alas, self-contradictory) conditions
504 * results in pretty ugly and hairy code with obscure logic.
505 *
506 * I chose to generalized it instead, so that the size
507 * of code does not increase practically, but it becomes
508 * much more general.
509 * Every prefix is assigned a "scope" value: "host" is local address,
510 * "link" is direct route,
511 * [ ... "site" ... "interior" ... ]
512 * and "universe" is true gateway route with global meaning.
513 *
514 * Every prefix refers to a set of "nexthop"s (gw, oif),
515 * where gw must have narrower scope. This recursion stops
516 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
517 * which means that gw is forced to be on link.
518 *
519 * Code is still hairy, but now it is apparently logically
520 * consistent and very flexible. F.e. as by-product it allows
521 * to co-exists in peace independent exterior and interior
522 * routing processes.
523 *
524 * Normally it looks as following.
525 *
526 * {universe prefix} -> (gw, oif) [scope link]
527 * |
528 * |-> {link prefix} -> (gw, oif) [scope local]
529 * |
530 * |-> {local prefix} (terminal node)
531 */
532 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
533 struct fib_nh *nh)
534 {
535 int err;
536 struct net *net;
537 struct net_device *dev;
538
539 net = cfg->fc_nlinfo.nl_net;
540 if (nh->nh_gw) {
541 struct fib_result res;
542
543 if (nh->nh_flags & RTNH_F_ONLINK) {
544
545 if (cfg->fc_scope >= RT_SCOPE_LINK)
546 return -EINVAL;
547 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
548 return -EINVAL;
549 dev = __dev_get_by_index(net, nh->nh_oif);
550 if (!dev)
551 return -ENODEV;
552 if (!(dev->flags & IFF_UP))
553 return -ENETDOWN;
554 nh->nh_dev = dev;
555 dev_hold(dev);
556 nh->nh_scope = RT_SCOPE_LINK;
557 return 0;
558 }
559 rcu_read_lock();
560 {
561 struct flowi4 fl4 = {
562 .daddr = nh->nh_gw,
563 .flowi4_scope = cfg->fc_scope + 1,
564 .flowi4_oif = nh->nh_oif,
565 };
566
567 /* It is not necessary, but requires a bit of thinking */
568 if (fl4.flowi4_scope < RT_SCOPE_LINK)
569 fl4.flowi4_scope = RT_SCOPE_LINK;
570 err = fib_lookup(net, &fl4, &res);
571 if (err) {
572 rcu_read_unlock();
573 return err;
574 }
575 }
576 err = -EINVAL;
577 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
578 goto out;
579 nh->nh_scope = res.scope;
580 nh->nh_oif = FIB_RES_OIF(res);
581 nh->nh_dev = dev = FIB_RES_DEV(res);
582 if (!dev)
583 goto out;
584 dev_hold(dev);
585 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
586 } else {
587 struct in_device *in_dev;
588
589 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
590 return -EINVAL;
591
592 rcu_read_lock();
593 err = -ENODEV;
594 in_dev = inetdev_by_index(net, nh->nh_oif);
595 if (in_dev == NULL)
596 goto out;
597 err = -ENETDOWN;
598 if (!(in_dev->dev->flags & IFF_UP))
599 goto out;
600 nh->nh_dev = in_dev->dev;
601 dev_hold(nh->nh_dev);
602 nh->nh_scope = RT_SCOPE_HOST;
603 err = 0;
604 }
605 out:
606 rcu_read_unlock();
607 return err;
608 }
609
610 static inline unsigned int fib_laddr_hashfn(__be32 val)
611 {
612 unsigned int mask = (fib_info_hash_size - 1);
613
614 return ((__force u32)val ^
615 ((__force u32)val >> 7) ^
616 ((__force u32)val >> 14)) & mask;
617 }
618
619 static struct hlist_head *fib_info_hash_alloc(int bytes)
620 {
621 if (bytes <= PAGE_SIZE)
622 return kzalloc(bytes, GFP_KERNEL);
623 else
624 return (struct hlist_head *)
625 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
626 get_order(bytes));
627 }
628
629 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
630 {
631 if (!hash)
632 return;
633
634 if (bytes <= PAGE_SIZE)
635 kfree(hash);
636 else
637 free_pages((unsigned long) hash, get_order(bytes));
638 }
639
640 static void fib_info_hash_move(struct hlist_head *new_info_hash,
641 struct hlist_head *new_laddrhash,
642 unsigned int new_size)
643 {
644 struct hlist_head *old_info_hash, *old_laddrhash;
645 unsigned int old_size = fib_info_hash_size;
646 unsigned int i, bytes;
647
648 spin_lock_bh(&fib_info_lock);
649 old_info_hash = fib_info_hash;
650 old_laddrhash = fib_info_laddrhash;
651 fib_info_hash_size = new_size;
652
653 for (i = 0; i < old_size; i++) {
654 struct hlist_head *head = &fib_info_hash[i];
655 struct hlist_node *node, *n;
656 struct fib_info *fi;
657
658 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
659 struct hlist_head *dest;
660 unsigned int new_hash;
661
662 hlist_del(&fi->fib_hash);
663
664 new_hash = fib_info_hashfn(fi);
665 dest = &new_info_hash[new_hash];
666 hlist_add_head(&fi->fib_hash, dest);
667 }
668 }
669 fib_info_hash = new_info_hash;
670
671 for (i = 0; i < old_size; i++) {
672 struct hlist_head *lhead = &fib_info_laddrhash[i];
673 struct hlist_node *node, *n;
674 struct fib_info *fi;
675
676 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
677 struct hlist_head *ldest;
678 unsigned int new_hash;
679
680 hlist_del(&fi->fib_lhash);
681
682 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
683 ldest = &new_laddrhash[new_hash];
684 hlist_add_head(&fi->fib_lhash, ldest);
685 }
686 }
687 fib_info_laddrhash = new_laddrhash;
688
689 spin_unlock_bh(&fib_info_lock);
690
691 bytes = old_size * sizeof(struct hlist_head *);
692 fib_info_hash_free(old_info_hash, bytes);
693 fib_info_hash_free(old_laddrhash, bytes);
694 }
695
696 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
697 {
698 nh->nh_saddr = inet_select_addr(nh->nh_dev,
699 nh->nh_gw,
700 nh->nh_parent->fib_scope);
701 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
702
703 return nh->nh_saddr;
704 }
705
706 struct fib_info *fib_create_info(struct fib_config *cfg)
707 {
708 int err;
709 struct fib_info *fi = NULL;
710 struct fib_info *ofi;
711 int nhs = 1;
712 struct net *net = cfg->fc_nlinfo.nl_net;
713
714 if (cfg->fc_type > RTN_MAX)
715 goto err_inval;
716
717 /* Fast check to catch the most weird cases */
718 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
719 goto err_inval;
720
721 #ifdef CONFIG_IP_ROUTE_MULTIPATH
722 if (cfg->fc_mp) {
723 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
724 if (nhs == 0)
725 goto err_inval;
726 }
727 #endif
728
729 err = -ENOBUFS;
730 if (fib_info_cnt >= fib_info_hash_size) {
731 unsigned int new_size = fib_info_hash_size << 1;
732 struct hlist_head *new_info_hash;
733 struct hlist_head *new_laddrhash;
734 unsigned int bytes;
735
736 if (!new_size)
737 new_size = 1;
738 bytes = new_size * sizeof(struct hlist_head *);
739 new_info_hash = fib_info_hash_alloc(bytes);
740 new_laddrhash = fib_info_hash_alloc(bytes);
741 if (!new_info_hash || !new_laddrhash) {
742 fib_info_hash_free(new_info_hash, bytes);
743 fib_info_hash_free(new_laddrhash, bytes);
744 } else
745 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
746
747 if (!fib_info_hash_size)
748 goto failure;
749 }
750
751 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
752 if (fi == NULL)
753 goto failure;
754 if (cfg->fc_mx) {
755 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
756 if (!fi->fib_metrics)
757 goto failure;
758 } else
759 fi->fib_metrics = (u32 *) dst_default_metrics;
760 fib_info_cnt++;
761
762 fi->fib_net = hold_net(net);
763 fi->fib_protocol = cfg->fc_protocol;
764 fi->fib_scope = cfg->fc_scope;
765 fi->fib_flags = cfg->fc_flags;
766 fi->fib_priority = cfg->fc_priority;
767 fi->fib_prefsrc = cfg->fc_prefsrc;
768
769 fi->fib_nhs = nhs;
770 change_nexthops(fi) {
771 nexthop_nh->nh_parent = fi;
772 } endfor_nexthops(fi)
773
774 if (cfg->fc_mx) {
775 struct nlattr *nla;
776 int remaining;
777
778 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
779 int type = nla_type(nla);
780
781 if (type) {
782 if (type > RTAX_MAX)
783 goto err_inval;
784 fi->fib_metrics[type - 1] = nla_get_u32(nla);
785 }
786 }
787 }
788
789 if (cfg->fc_mp) {
790 #ifdef CONFIG_IP_ROUTE_MULTIPATH
791 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
792 if (err != 0)
793 goto failure;
794 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
795 goto err_inval;
796 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
797 goto err_inval;
798 #ifdef CONFIG_IP_ROUTE_CLASSID
799 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
800 goto err_inval;
801 #endif
802 #else
803 goto err_inval;
804 #endif
805 } else {
806 struct fib_nh *nh = fi->fib_nh;
807
808 nh->nh_oif = cfg->fc_oif;
809 nh->nh_gw = cfg->fc_gw;
810 nh->nh_flags = cfg->fc_flags;
811 #ifdef CONFIG_IP_ROUTE_CLASSID
812 nh->nh_tclassid = cfg->fc_flow;
813 #endif
814 #ifdef CONFIG_IP_ROUTE_MULTIPATH
815 nh->nh_weight = 1;
816 #endif
817 }
818
819 if (fib_props[cfg->fc_type].error) {
820 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
821 goto err_inval;
822 goto link_it;
823 } else {
824 switch (cfg->fc_type) {
825 case RTN_UNICAST:
826 case RTN_LOCAL:
827 case RTN_BROADCAST:
828 case RTN_ANYCAST:
829 case RTN_MULTICAST:
830 break;
831 default:
832 goto err_inval;
833 }
834 }
835
836 if (cfg->fc_scope > RT_SCOPE_HOST)
837 goto err_inval;
838
839 if (cfg->fc_scope == RT_SCOPE_HOST) {
840 struct fib_nh *nh = fi->fib_nh;
841
842 /* Local address is added. */
843 if (nhs != 1 || nh->nh_gw)
844 goto err_inval;
845 nh->nh_scope = RT_SCOPE_NOWHERE;
846 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
847 err = -ENODEV;
848 if (nh->nh_dev == NULL)
849 goto failure;
850 } else {
851 change_nexthops(fi) {
852 err = fib_check_nh(cfg, fi, nexthop_nh);
853 if (err != 0)
854 goto failure;
855 } endfor_nexthops(fi)
856 }
857
858 if (fi->fib_prefsrc) {
859 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
860 fi->fib_prefsrc != cfg->fc_dst)
861 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
862 goto err_inval;
863 }
864
865 change_nexthops(fi) {
866 fib_info_update_nh_saddr(net, nexthop_nh);
867 } endfor_nexthops(fi)
868
869 link_it:
870 ofi = fib_find_info(fi);
871 if (ofi) {
872 fi->fib_dead = 1;
873 free_fib_info(fi);
874 ofi->fib_treeref++;
875 return ofi;
876 }
877
878 fi->fib_treeref++;
879 atomic_inc(&fi->fib_clntref);
880 spin_lock_bh(&fib_info_lock);
881 hlist_add_head(&fi->fib_hash,
882 &fib_info_hash[fib_info_hashfn(fi)]);
883 if (fi->fib_prefsrc) {
884 struct hlist_head *head;
885
886 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
887 hlist_add_head(&fi->fib_lhash, head);
888 }
889 change_nexthops(fi) {
890 struct hlist_head *head;
891 unsigned int hash;
892
893 if (!nexthop_nh->nh_dev)
894 continue;
895 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
896 head = &fib_info_devhash[hash];
897 hlist_add_head(&nexthop_nh->nh_hash, head);
898 } endfor_nexthops(fi)
899 spin_unlock_bh(&fib_info_lock);
900 return fi;
901
902 err_inval:
903 err = -EINVAL;
904
905 failure:
906 if (fi) {
907 fi->fib_dead = 1;
908 free_fib_info(fi);
909 }
910
911 return ERR_PTR(err);
912 }
913
914 int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
915 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
916 struct fib_info *fi, unsigned int flags)
917 {
918 struct nlmsghdr *nlh;
919 struct rtmsg *rtm;
920
921 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
922 if (nlh == NULL)
923 return -EMSGSIZE;
924
925 rtm = nlmsg_data(nlh);
926 rtm->rtm_family = AF_INET;
927 rtm->rtm_dst_len = dst_len;
928 rtm->rtm_src_len = 0;
929 rtm->rtm_tos = tos;
930 if (tb_id < 256)
931 rtm->rtm_table = tb_id;
932 else
933 rtm->rtm_table = RT_TABLE_COMPAT;
934 NLA_PUT_U32(skb, RTA_TABLE, tb_id);
935 rtm->rtm_type = type;
936 rtm->rtm_flags = fi->fib_flags;
937 rtm->rtm_scope = fi->fib_scope;
938 rtm->rtm_protocol = fi->fib_protocol;
939
940 if (rtm->rtm_dst_len)
941 NLA_PUT_BE32(skb, RTA_DST, dst);
942
943 if (fi->fib_priority)
944 NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
945
946 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
947 goto nla_put_failure;
948
949 if (fi->fib_prefsrc)
950 NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc);
951
952 if (fi->fib_nhs == 1) {
953 if (fi->fib_nh->nh_gw)
954 NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
955
956 if (fi->fib_nh->nh_oif)
957 NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
958 #ifdef CONFIG_IP_ROUTE_CLASSID
959 if (fi->fib_nh[0].nh_tclassid)
960 NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
961 #endif
962 }
963 #ifdef CONFIG_IP_ROUTE_MULTIPATH
964 if (fi->fib_nhs > 1) {
965 struct rtnexthop *rtnh;
966 struct nlattr *mp;
967
968 mp = nla_nest_start(skb, RTA_MULTIPATH);
969 if (mp == NULL)
970 goto nla_put_failure;
971
972 for_nexthops(fi) {
973 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
974 if (rtnh == NULL)
975 goto nla_put_failure;
976
977 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
978 rtnh->rtnh_hops = nh->nh_weight - 1;
979 rtnh->rtnh_ifindex = nh->nh_oif;
980
981 if (nh->nh_gw)
982 NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw);
983 #ifdef CONFIG_IP_ROUTE_CLASSID
984 if (nh->nh_tclassid)
985 NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
986 #endif
987 /* length of rtnetlink header + attributes */
988 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
989 } endfor_nexthops(fi);
990
991 nla_nest_end(skb, mp);
992 }
993 #endif
994 return nlmsg_end(skb, nlh);
995
996 nla_put_failure:
997 nlmsg_cancel(skb, nlh);
998 return -EMSGSIZE;
999 }
1000
1001 /*
1002 * Update FIB if:
1003 * - local address disappeared -> we must delete all the entries
1004 * referring to it.
1005 * - device went down -> we must shutdown all nexthops going via it.
1006 */
1007 int fib_sync_down_addr(struct net *net, __be32 local)
1008 {
1009 int ret = 0;
1010 unsigned int hash = fib_laddr_hashfn(local);
1011 struct hlist_head *head = &fib_info_laddrhash[hash];
1012 struct hlist_node *node;
1013 struct fib_info *fi;
1014
1015 if (fib_info_laddrhash == NULL || local == 0)
1016 return 0;
1017
1018 hlist_for_each_entry(fi, node, head, fib_lhash) {
1019 if (!net_eq(fi->fib_net, net))
1020 continue;
1021 if (fi->fib_prefsrc == local) {
1022 fi->fib_flags |= RTNH_F_DEAD;
1023 ret++;
1024 }
1025 }
1026 return ret;
1027 }
1028
1029 int fib_sync_down_dev(struct net_device *dev, int force)
1030 {
1031 int ret = 0;
1032 int scope = RT_SCOPE_NOWHERE;
1033 struct fib_info *prev_fi = NULL;
1034 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1035 struct hlist_head *head = &fib_info_devhash[hash];
1036 struct hlist_node *node;
1037 struct fib_nh *nh;
1038
1039 if (force)
1040 scope = -1;
1041
1042 hlist_for_each_entry(nh, node, head, nh_hash) {
1043 struct fib_info *fi = nh->nh_parent;
1044 int dead;
1045
1046 BUG_ON(!fi->fib_nhs);
1047 if (nh->nh_dev != dev || fi == prev_fi)
1048 continue;
1049 prev_fi = fi;
1050 dead = 0;
1051 change_nexthops(fi) {
1052 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1053 dead++;
1054 else if (nexthop_nh->nh_dev == dev &&
1055 nexthop_nh->nh_scope != scope) {
1056 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1057 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1058 spin_lock_bh(&fib_multipath_lock);
1059 fi->fib_power -= nexthop_nh->nh_power;
1060 nexthop_nh->nh_power = 0;
1061 spin_unlock_bh(&fib_multipath_lock);
1062 #endif
1063 dead++;
1064 }
1065 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1066 if (force > 1 && nexthop_nh->nh_dev == dev) {
1067 dead = fi->fib_nhs;
1068 break;
1069 }
1070 #endif
1071 } endfor_nexthops(fi)
1072 if (dead == fi->fib_nhs) {
1073 fi->fib_flags |= RTNH_F_DEAD;
1074 ret++;
1075 }
1076 }
1077
1078 return ret;
1079 }
1080
1081 /* Must be invoked inside of an RCU protected region. */
1082 void fib_select_default(struct fib_result *res)
1083 {
1084 struct fib_info *fi = NULL, *last_resort = NULL;
1085 struct list_head *fa_head = res->fa_head;
1086 struct fib_table *tb = res->table;
1087 int order = -1, last_idx = -1;
1088 struct fib_alias *fa;
1089
1090 list_for_each_entry_rcu(fa, fa_head, fa_list) {
1091 struct fib_info *next_fi = fa->fa_info;
1092
1093 if (next_fi->fib_scope != res->scope ||
1094 fa->fa_type != RTN_UNICAST)
1095 continue;
1096
1097 if (next_fi->fib_priority > res->fi->fib_priority)
1098 break;
1099 if (!next_fi->fib_nh[0].nh_gw ||
1100 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1101 continue;
1102
1103 fib_alias_accessed(fa);
1104
1105 if (fi == NULL) {
1106 if (next_fi != res->fi)
1107 break;
1108 } else if (!fib_detect_death(fi, order, &last_resort,
1109 &last_idx, tb->tb_default)) {
1110 fib_result_assign(res, fi);
1111 tb->tb_default = order;
1112 goto out;
1113 }
1114 fi = next_fi;
1115 order++;
1116 }
1117
1118 if (order <= 0 || fi == NULL) {
1119 tb->tb_default = -1;
1120 goto out;
1121 }
1122
1123 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1124 tb->tb_default)) {
1125 fib_result_assign(res, fi);
1126 tb->tb_default = order;
1127 goto out;
1128 }
1129
1130 if (last_idx >= 0)
1131 fib_result_assign(res, last_resort);
1132 tb->tb_default = last_idx;
1133 out:
1134 return;
1135 }
1136
1137 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1138
1139 /*
1140 * Dead device goes up. We wake up dead nexthops.
1141 * It takes sense only on multipath routes.
1142 */
1143 int fib_sync_up(struct net_device *dev)
1144 {
1145 struct fib_info *prev_fi;
1146 unsigned int hash;
1147 struct hlist_head *head;
1148 struct hlist_node *node;
1149 struct fib_nh *nh;
1150 int ret;
1151
1152 if (!(dev->flags & IFF_UP))
1153 return 0;
1154
1155 prev_fi = NULL;
1156 hash = fib_devindex_hashfn(dev->ifindex);
1157 head = &fib_info_devhash[hash];
1158 ret = 0;
1159
1160 hlist_for_each_entry(nh, node, head, nh_hash) {
1161 struct fib_info *fi = nh->nh_parent;
1162 int alive;
1163
1164 BUG_ON(!fi->fib_nhs);
1165 if (nh->nh_dev != dev || fi == prev_fi)
1166 continue;
1167
1168 prev_fi = fi;
1169 alive = 0;
1170 change_nexthops(fi) {
1171 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1172 alive++;
1173 continue;
1174 }
1175 if (nexthop_nh->nh_dev == NULL ||
1176 !(nexthop_nh->nh_dev->flags & IFF_UP))
1177 continue;
1178 if (nexthop_nh->nh_dev != dev ||
1179 !__in_dev_get_rtnl(dev))
1180 continue;
1181 alive++;
1182 spin_lock_bh(&fib_multipath_lock);
1183 nexthop_nh->nh_power = 0;
1184 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1185 spin_unlock_bh(&fib_multipath_lock);
1186 } endfor_nexthops(fi)
1187
1188 if (alive > 0) {
1189 fi->fib_flags &= ~RTNH_F_DEAD;
1190 ret++;
1191 }
1192 }
1193
1194 return ret;
1195 }
1196
1197 /*
1198 * The algorithm is suboptimal, but it provides really
1199 * fair weighted route distribution.
1200 */
1201 void fib_select_multipath(struct fib_result *res)
1202 {
1203 struct fib_info *fi = res->fi;
1204 int w;
1205
1206 spin_lock_bh(&fib_multipath_lock);
1207 if (fi->fib_power <= 0) {
1208 int power = 0;
1209 change_nexthops(fi) {
1210 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1211 power += nexthop_nh->nh_weight;
1212 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1213 }
1214 } endfor_nexthops(fi);
1215 fi->fib_power = power;
1216 if (power <= 0) {
1217 spin_unlock_bh(&fib_multipath_lock);
1218 /* Race condition: route has just become dead. */
1219 res->nh_sel = 0;
1220 return;
1221 }
1222 }
1223
1224
1225 /* w should be random number [0..fi->fib_power-1],
1226 * it is pretty bad approximation.
1227 */
1228
1229 w = jiffies % fi->fib_power;
1230
1231 change_nexthops(fi) {
1232 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1233 nexthop_nh->nh_power) {
1234 w -= nexthop_nh->nh_power;
1235 if (w <= 0) {
1236 nexthop_nh->nh_power--;
1237 fi->fib_power--;
1238 res->nh_sel = nhsel;
1239 spin_unlock_bh(&fib_multipath_lock);
1240 return;
1241 }
1242 }
1243 } endfor_nexthops(fi);
1244
1245 /* Race condition: route has just become dead. */
1246 res->nh_sel = 0;
1247 spin_unlock_bh(&fib_multipath_lock);
1248 }
1249 #endif
Linus' kernel tree