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KEYS: Fix up comments in key management code
[linux-2.6/next.git] / net / ipv4 / fib_semantics.c
blob12d3dc3df1b7d683e94cbf42140a9ac40b35029d
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 <asm/system.h>
18 #include <linux/bitops.h>
19 #include <linux/types.h>
20 #include <linux/kernel.h>
21 #include <linux/jiffies.h>
22 #include <linux/mm.h>
23 #include <linux/string.h>
24 #include <linux/socket.h>
25 #include <linux/sockios.h>
26 #include <linux/errno.h>
27 #include <linux/in.h>
28 #include <linux/inet.h>
29 #include <linux/inetdevice.h>
30 #include <linux/netdevice.h>
31 #include <linux/if_arp.h>
32 #include <linux/proc_fs.h>
33 #include <linux/skbuff.h>
34 #include <linux/init.h>
35 #include <linux/slab.h>
36
37 #include <net/arp.h>
38 #include <net/ip.h>
39 #include <net/protocol.h>
40 #include <net/route.h>
41 #include <net/tcp.h>
42 #include <net/sock.h>
43 #include <net/ip_fib.h>
44 #include <net/netlink.h>
45 #include <net/nexthop.h>
46
47 #include "fib_lookup.h"
48
49 static DEFINE_SPINLOCK(fib_info_lock);
50 static struct hlist_head *fib_info_hash;
51 static struct hlist_head *fib_info_laddrhash;
52 static unsigned int fib_hash_size;
53 static unsigned int fib_info_cnt;
54
55 #define DEVINDEX_HASHBITS 8
56 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59 #ifdef CONFIG_IP_ROUTE_MULTIPATH
60
61 static DEFINE_SPINLOCK(fib_multipath_lock);
62
63 #define for_nexthops(fi) { \
64 int nhsel; const struct fib_nh *nh; \
65 for (nhsel = 0, nh = (fi)->fib_nh; \
66 nhsel < (fi)->fib_nhs; \
67 nh++, nhsel++)
68
69 #define change_nexthops(fi) { \
70 int nhsel; struct fib_nh *nexthop_nh; \
71 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
72 nhsel < (fi)->fib_nhs; \
73 nexthop_nh++, nhsel++)
74
75 #else /* CONFIG_IP_ROUTE_MULTIPATH */
76
77 /* Hope, that gcc will optimize it to get rid of dummy loop */
78
79 #define for_nexthops(fi) { \
80 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
81 for (nhsel = 0; nhsel < 1; nhsel++)
82
83 #define change_nexthops(fi) { \
84 int nhsel; \
85 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
86 for (nhsel = 0; nhsel < 1; nhsel++)
87
88 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
89
90 #define endfor_nexthops(fi) }
91
92
93 static const struct
94 {
95 int error;
96 u8 scope;
97 } fib_props[RTN_MAX + 1] = {
98 [RTN_UNSPEC] = {
99 .error = 0,
100 .scope = RT_SCOPE_NOWHERE,
101 },
102 [RTN_UNICAST] = {
103 .error = 0,
104 .scope = RT_SCOPE_UNIVERSE,
105 },
106 [RTN_LOCAL] = {
107 .error = 0,
108 .scope = RT_SCOPE_HOST,
109 },
110 [RTN_BROADCAST] = {
111 .error = 0,
112 .scope = RT_SCOPE_LINK,
113 },
114 [RTN_ANYCAST] = {
115 .error = 0,
116 .scope = RT_SCOPE_LINK,
117 },
118 [RTN_MULTICAST] = {
119 .error = 0,
120 .scope = RT_SCOPE_UNIVERSE,
121 },
122 [RTN_BLACKHOLE] = {
123 .error = -EINVAL,
124 .scope = RT_SCOPE_UNIVERSE,
125 },
126 [RTN_UNREACHABLE] = {
127 .error = -EHOSTUNREACH,
128 .scope = RT_SCOPE_UNIVERSE,
129 },
130 [RTN_PROHIBIT] = {
131 .error = -EACCES,
132 .scope = RT_SCOPE_UNIVERSE,
133 },
134 [RTN_THROW] = {
135 .error = -EAGAIN,
136 .scope = RT_SCOPE_UNIVERSE,
137 },
138 [RTN_NAT] = {
139 .error = -EINVAL,
140 .scope = RT_SCOPE_NOWHERE,
141 },
142 [RTN_XRESOLVE] = {
143 .error = -EINVAL,
144 .scope = RT_SCOPE_NOWHERE,
145 },
146 };
147
148
149 /* Release a nexthop info record */
150
151 static void free_fib_info_rcu(struct rcu_head *head)
152 {
153 struct fib_info *fi = container_of(head, struct fib_info, rcu);
154
155 kfree(fi);
156 }
157
158 void free_fib_info(struct fib_info *fi)
159 {
160 if (fi->fib_dead == 0) {
161 pr_warning("Freeing alive fib_info %p\n", fi);
162 return;
163 }
164 change_nexthops(fi) {
165 if (nexthop_nh->nh_dev)
166 dev_put(nexthop_nh->nh_dev);
167 nexthop_nh->nh_dev = NULL;
168 } endfor_nexthops(fi);
169 fib_info_cnt--;
170 release_net(fi->fib_net);
171 call_rcu(&fi->rcu, free_fib_info_rcu);
172 }
173
174 void fib_release_info(struct fib_info *fi)
175 {
176 spin_lock_bh(&fib_info_lock);
177 if (fi && --fi->fib_treeref == 0) {
178 hlist_del(&fi->fib_hash);
179 if (fi->fib_prefsrc)
180 hlist_del(&fi->fib_lhash);
181 change_nexthops(fi) {
182 if (!nexthop_nh->nh_dev)
183 continue;
184 hlist_del(&nexthop_nh->nh_hash);
185 } endfor_nexthops(fi)
186 fi->fib_dead = 1;
187 fib_info_put(fi);
188 }
189 spin_unlock_bh(&fib_info_lock);
190 }
191
192 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
193 {
194 const struct fib_nh *onh = ofi->fib_nh;
195
196 for_nexthops(fi) {
197 if (nh->nh_oif != onh->nh_oif ||
198 nh->nh_gw != onh->nh_gw ||
199 nh->nh_scope != onh->nh_scope ||
200 #ifdef CONFIG_IP_ROUTE_MULTIPATH
201 nh->nh_weight != onh->nh_weight ||
202 #endif
203 #ifdef CONFIG_NET_CLS_ROUTE
204 nh->nh_tclassid != onh->nh_tclassid ||
205 #endif
206 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
207 return -1;
208 onh++;
209 } endfor_nexthops(fi);
210 return 0;
211 }
212
213 static inline unsigned int fib_devindex_hashfn(unsigned int val)
214 {
215 unsigned int mask = DEVINDEX_HASHSIZE - 1;
216
217 return (val ^
218 (val >> DEVINDEX_HASHBITS) ^
219 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
220 }
221
222 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
223 {
224 unsigned int mask = (fib_hash_size - 1);
225 unsigned int val = fi->fib_nhs;
226
227 val ^= fi->fib_protocol;
228 val ^= (__force u32)fi->fib_prefsrc;
229 val ^= fi->fib_priority;
230 for_nexthops(fi) {
231 val ^= fib_devindex_hashfn(nh->nh_oif);
232 } endfor_nexthops(fi)
233
234 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
235 }
236
237 static struct fib_info *fib_find_info(const struct fib_info *nfi)
238 {
239 struct hlist_head *head;
240 struct hlist_node *node;
241 struct fib_info *fi;
242 unsigned int hash;
243
244 hash = fib_info_hashfn(nfi);
245 head = &fib_info_hash[hash];
246
247 hlist_for_each_entry(fi, node, head, fib_hash) {
248 if (!net_eq(fi->fib_net, nfi->fib_net))
249 continue;
250 if (fi->fib_nhs != nfi->fib_nhs)
251 continue;
252 if (nfi->fib_protocol == fi->fib_protocol &&
253 nfi->fib_prefsrc == fi->fib_prefsrc &&
254 nfi->fib_priority == fi->fib_priority &&
255 memcmp(nfi->fib_metrics, fi->fib_metrics,
256 sizeof(fi->fib_metrics)) == 0 &&
257 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
258 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
259 return fi;
260 }
261
262 return NULL;
263 }
264
265 /* Check, that the gateway is already configured.
266 * Used only by redirect accept routine.
267 */
268 int ip_fib_check_default(__be32 gw, struct net_device *dev)
269 {
270 struct hlist_head *head;
271 struct hlist_node *node;
272 struct fib_nh *nh;
273 unsigned int hash;
274
275 spin_lock(&fib_info_lock);
276
277 hash = fib_devindex_hashfn(dev->ifindex);
278 head = &fib_info_devhash[hash];
279 hlist_for_each_entry(nh, node, head, nh_hash) {
280 if (nh->nh_dev == dev &&
281 nh->nh_gw == gw &&
282 !(nh->nh_flags & RTNH_F_DEAD)) {
283 spin_unlock(&fib_info_lock);
284 return 0;
285 }
286 }
287
288 spin_unlock(&fib_info_lock);
289
290 return -1;
291 }
292
293 static inline size_t fib_nlmsg_size(struct fib_info *fi)
294 {
295 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
296 + nla_total_size(4) /* RTA_TABLE */
297 + nla_total_size(4) /* RTA_DST */
298 + nla_total_size(4) /* RTA_PRIORITY */
299 + nla_total_size(4); /* RTA_PREFSRC */
300
301 /* space for nested metrics */
302 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
303
304 if (fi->fib_nhs) {
305 /* Also handles the special case fib_nhs == 1 */
306
307 /* each nexthop is packed in an attribute */
308 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
309
310 /* may contain flow and gateway attribute */
311 nhsize += 2 * nla_total_size(4);
312
313 /* all nexthops are packed in a nested attribute */
314 payload += nla_total_size(fi->fib_nhs * nhsize);
315 }
316
317 return payload;
318 }
319
320 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
321 int dst_len, u32 tb_id, struct nl_info *info,
322 unsigned int nlm_flags)
323 {
324 struct sk_buff *skb;
325 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
326 int err = -ENOBUFS;
327
328 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
329 if (skb == NULL)
330 goto errout;
331
332 err = fib_dump_info(skb, info->pid, seq, event, tb_id,
333 fa->fa_type, fa->fa_scope, key, dst_len,
334 fa->fa_tos, fa->fa_info, nlm_flags);
335 if (err < 0) {
336 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
337 WARN_ON(err == -EMSGSIZE);
338 kfree_skb(skb);
339 goto errout;
340 }
341 rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
342 info->nlh, GFP_KERNEL);
343 return;
344 errout:
345 if (err < 0)
346 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
347 }
348
349 /* Return the first fib alias matching TOS with
350 * priority less than or equal to PRIO.
351 */
352 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
353 {
354 if (fah) {
355 struct fib_alias *fa;
356 list_for_each_entry(fa, fah, fa_list) {
357 if (fa->fa_tos > tos)
358 continue;
359 if (fa->fa_info->fib_priority >= prio ||
360 fa->fa_tos < tos)
361 return fa;
362 }
363 }
364 return NULL;
365 }
366
367 int fib_detect_death(struct fib_info *fi, int order,
368 struct fib_info **last_resort, int *last_idx, int dflt)
369 {
370 struct neighbour *n;
371 int state = NUD_NONE;
372
373 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
374 if (n) {
375 state = n->nud_state;
376 neigh_release(n);
377 }
378 if (state == NUD_REACHABLE)
379 return 0;
380 if ((state & NUD_VALID) && order != dflt)
381 return 0;
382 if ((state & NUD_VALID) ||
383 (*last_idx < 0 && order > dflt)) {
384 *last_resort = fi;
385 *last_idx = order;
386 }
387 return 1;
388 }
389
390 #ifdef CONFIG_IP_ROUTE_MULTIPATH
391
392 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
393 {
394 int nhs = 0;
395
396 while (rtnh_ok(rtnh, remaining)) {
397 nhs++;
398 rtnh = rtnh_next(rtnh, &remaining);
399 }
400
401 /* leftover implies invalid nexthop configuration, discard it */
402 return remaining > 0 ? 0 : nhs;
403 }
404
405 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
406 int remaining, struct fib_config *cfg)
407 {
408 change_nexthops(fi) {
409 int attrlen;
410
411 if (!rtnh_ok(rtnh, remaining))
412 return -EINVAL;
413
414 nexthop_nh->nh_flags =
415 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
416 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
417 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
418
419 attrlen = rtnh_attrlen(rtnh);
420 if (attrlen > 0) {
421 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
422
423 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
424 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
425 #ifdef CONFIG_NET_CLS_ROUTE
426 nla = nla_find(attrs, attrlen, RTA_FLOW);
427 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
428 #endif
429 }
430
431 rtnh = rtnh_next(rtnh, &remaining);
432 } endfor_nexthops(fi);
433
434 return 0;
435 }
436
437 #endif
438
439 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
440 {
441 #ifdef CONFIG_IP_ROUTE_MULTIPATH
442 struct rtnexthop *rtnh;
443 int remaining;
444 #endif
445
446 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
447 return 1;
448
449 if (cfg->fc_oif || cfg->fc_gw) {
450 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
451 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
452 return 0;
453 return 1;
454 }
455
456 #ifdef CONFIG_IP_ROUTE_MULTIPATH
457 if (cfg->fc_mp == NULL)
458 return 0;
459
460 rtnh = cfg->fc_mp;
461 remaining = cfg->fc_mp_len;
462
463 for_nexthops(fi) {
464 int attrlen;
465
466 if (!rtnh_ok(rtnh, remaining))
467 return -EINVAL;
468
469 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
470 return 1;
471
472 attrlen = rtnh_attrlen(rtnh);
473 if (attrlen < 0) {
474 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
475
476 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
477 if (nla && nla_get_be32(nla) != nh->nh_gw)
478 return 1;
479 #ifdef CONFIG_NET_CLS_ROUTE
480 nla = nla_find(attrs, attrlen, RTA_FLOW);
481 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
482 return 1;
483 #endif
484 }
485
486 rtnh = rtnh_next(rtnh, &remaining);
487 } endfor_nexthops(fi);
488 #endif
489 return 0;
490 }
491
492
493 /*
494 * Picture
495 * -------
496 *
497 * Semantics of nexthop is very messy by historical reasons.
498 * We have to take into account, that:
499 * a) gateway can be actually local interface address,
500 * so that gatewayed route is direct.
501 * b) gateway must be on-link address, possibly
502 * described not by an ifaddr, but also by a direct route.
503 * c) If both gateway and interface are specified, they should not
504 * contradict.
505 * d) If we use tunnel routes, gateway could be not on-link.
506 *
507 * Attempt to reconcile all of these (alas, self-contradictory) conditions
508 * results in pretty ugly and hairy code with obscure logic.
509 *
510 * I chose to generalized it instead, so that the size
511 * of code does not increase practically, but it becomes
512 * much more general.
513 * Every prefix is assigned a "scope" value: "host" is local address,
514 * "link" is direct route,
515 * [ ... "site" ... "interior" ... ]
516 * and "universe" is true gateway route with global meaning.
517 *
518 * Every prefix refers to a set of "nexthop"s (gw, oif),
519 * where gw must have narrower scope. This recursion stops
520 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
521 * which means that gw is forced to be on link.
522 *
523 * Code is still hairy, but now it is apparently logically
524 * consistent and very flexible. F.e. as by-product it allows
525 * to co-exists in peace independent exterior and interior
526 * routing processes.
527 *
528 * Normally it looks as following.
529 *
530 * {universe prefix} -> (gw, oif) [scope link]
531 * |
532 * |-> {link prefix} -> (gw, oif) [scope local]
533 * |
534 * |-> {local prefix} (terminal node)
535 */
536 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
537 struct fib_nh *nh)
538 {
539 int err;
540 struct net *net;
541 struct net_device *dev;
542
543 net = cfg->fc_nlinfo.nl_net;
544 if (nh->nh_gw) {
545 struct fib_result res;
546
547 if (nh->nh_flags & RTNH_F_ONLINK) {
548
549 if (cfg->fc_scope >= RT_SCOPE_LINK)
550 return -EINVAL;
551 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
552 return -EINVAL;
553 dev = __dev_get_by_index(net, nh->nh_oif);
554 if (!dev)
555 return -ENODEV;
556 if (!(dev->flags & IFF_UP))
557 return -ENETDOWN;
558 nh->nh_dev = dev;
559 dev_hold(dev);
560 nh->nh_scope = RT_SCOPE_LINK;
561 return 0;
562 }
563 rcu_read_lock();
564 {
565 struct flowi fl = {
566 .fl4_dst = nh->nh_gw,
567 .fl4_scope = cfg->fc_scope + 1,
568 .oif = nh->nh_oif,
569 };
570
571 /* It is not necessary, but requires a bit of thinking */
572 if (fl.fl4_scope < RT_SCOPE_LINK)
573 fl.fl4_scope = RT_SCOPE_LINK;
574 err = fib_lookup(net, &fl, &res);
575 if (err) {
576 rcu_read_unlock();
577 return err;
578 }
579 }
580 err = -EINVAL;
581 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
582 goto out;
583 nh->nh_scope = res.scope;
584 nh->nh_oif = FIB_RES_OIF(res);
585 nh->nh_dev = dev = FIB_RES_DEV(res);
586 if (!dev)
587 goto out;
588 dev_hold(dev);
589 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
590 } else {
591 struct in_device *in_dev;
592
593 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
594 return -EINVAL;
595
596 rcu_read_lock();
597 err = -ENODEV;
598 in_dev = inetdev_by_index(net, nh->nh_oif);
599 if (in_dev == NULL)
600 goto out;
601 err = -ENETDOWN;
602 if (!(in_dev->dev->flags & IFF_UP))
603 goto out;
604 nh->nh_dev = in_dev->dev;
605 dev_hold(nh->nh_dev);
606 nh->nh_scope = RT_SCOPE_HOST;
607 err = 0;
608 }
609 out:
610 rcu_read_unlock();
611 return err;
612 }
613
614 static inline unsigned int fib_laddr_hashfn(__be32 val)
615 {
616 unsigned int mask = (fib_hash_size - 1);
617
618 return ((__force u32)val ^
619 ((__force u32)val >> 7) ^
620 ((__force u32)val >> 14)) & mask;
621 }
622
623 static struct hlist_head *fib_hash_alloc(int bytes)
624 {
625 if (bytes <= PAGE_SIZE)
626 return kzalloc(bytes, GFP_KERNEL);
627 else
628 return (struct hlist_head *)
629 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
630 get_order(bytes));
631 }
632
633 static void fib_hash_free(struct hlist_head *hash, int bytes)
634 {
635 if (!hash)
636 return;
637
638 if (bytes <= PAGE_SIZE)
639 kfree(hash);
640 else
641 free_pages((unsigned long) hash, get_order(bytes));
642 }
643
644 static void fib_hash_move(struct hlist_head *new_info_hash,
645 struct hlist_head *new_laddrhash,
646 unsigned int new_size)
647 {
648 struct hlist_head *old_info_hash, *old_laddrhash;
649 unsigned int old_size = fib_hash_size;
650 unsigned int i, bytes;
651
652 spin_lock_bh(&fib_info_lock);
653 old_info_hash = fib_info_hash;
654 old_laddrhash = fib_info_laddrhash;
655 fib_hash_size = new_size;
656
657 for (i = 0; i < old_size; i++) {
658 struct hlist_head *head = &fib_info_hash[i];
659 struct hlist_node *node, *n;
660 struct fib_info *fi;
661
662 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
663 struct hlist_head *dest;
664 unsigned int new_hash;
665
666 hlist_del(&fi->fib_hash);
667
668 new_hash = fib_info_hashfn(fi);
669 dest = &new_info_hash[new_hash];
670 hlist_add_head(&fi->fib_hash, dest);
671 }
672 }
673 fib_info_hash = new_info_hash;
674
675 for (i = 0; i < old_size; i++) {
676 struct hlist_head *lhead = &fib_info_laddrhash[i];
677 struct hlist_node *node, *n;
678 struct fib_info *fi;
679
680 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
681 struct hlist_head *ldest;
682 unsigned int new_hash;
683
684 hlist_del(&fi->fib_lhash);
685
686 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
687 ldest = &new_laddrhash[new_hash];
688 hlist_add_head(&fi->fib_lhash, ldest);
689 }
690 }
691 fib_info_laddrhash = new_laddrhash;
692
693 spin_unlock_bh(&fib_info_lock);
694
695 bytes = old_size * sizeof(struct hlist_head *);
696 fib_hash_free(old_info_hash, bytes);
697 fib_hash_free(old_laddrhash, bytes);
698 }
699
700 struct fib_info *fib_create_info(struct fib_config *cfg)
701 {
702 int err;
703 struct fib_info *fi = NULL;
704 struct fib_info *ofi;
705 int nhs = 1;
706 struct net *net = cfg->fc_nlinfo.nl_net;
707
708 /* Fast check to catch the most weird cases */
709 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
710 goto err_inval;
711
712 #ifdef CONFIG_IP_ROUTE_MULTIPATH
713 if (cfg->fc_mp) {
714 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
715 if (nhs == 0)
716 goto err_inval;
717 }
718 #endif
719
720 err = -ENOBUFS;
721 if (fib_info_cnt >= fib_hash_size) {
722 unsigned int new_size = fib_hash_size << 1;
723 struct hlist_head *new_info_hash;
724 struct hlist_head *new_laddrhash;
725 unsigned int bytes;
726
727 if (!new_size)
728 new_size = 1;
729 bytes = new_size * sizeof(struct hlist_head *);
730 new_info_hash = fib_hash_alloc(bytes);
731 new_laddrhash = fib_hash_alloc(bytes);
732 if (!new_info_hash || !new_laddrhash) {
733 fib_hash_free(new_info_hash, bytes);
734 fib_hash_free(new_laddrhash, bytes);
735 } else
736 fib_hash_move(new_info_hash, new_laddrhash, new_size);
737
738 if (!fib_hash_size)
739 goto failure;
740 }
741
742 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
743 if (fi == NULL)
744 goto failure;
745 fib_info_cnt++;
746
747 fi->fib_net = hold_net(net);
748 fi->fib_protocol = cfg->fc_protocol;
749 fi->fib_flags = cfg->fc_flags;
750 fi->fib_priority = cfg->fc_priority;
751 fi->fib_prefsrc = cfg->fc_prefsrc;
752
753 fi->fib_nhs = nhs;
754 change_nexthops(fi) {
755 nexthop_nh->nh_parent = fi;
756 } endfor_nexthops(fi)
757
758 if (cfg->fc_mx) {
759 struct nlattr *nla;
760 int remaining;
761
762 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
763 int type = nla_type(nla);
764
765 if (type) {
766 if (type > RTAX_MAX)
767 goto err_inval;
768 fi->fib_metrics[type - 1] = nla_get_u32(nla);
769 }
770 }
771 }
772
773 if (cfg->fc_mp) {
774 #ifdef CONFIG_IP_ROUTE_MULTIPATH
775 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
776 if (err != 0)
777 goto failure;
778 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
779 goto err_inval;
780 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
781 goto err_inval;
782 #ifdef CONFIG_NET_CLS_ROUTE
783 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
784 goto err_inval;
785 #endif
786 #else
787 goto err_inval;
788 #endif
789 } else {
790 struct fib_nh *nh = fi->fib_nh;
791
792 nh->nh_oif = cfg->fc_oif;
793 nh->nh_gw = cfg->fc_gw;
794 nh->nh_flags = cfg->fc_flags;
795 #ifdef CONFIG_NET_CLS_ROUTE
796 nh->nh_tclassid = cfg->fc_flow;
797 #endif
798 #ifdef CONFIG_IP_ROUTE_MULTIPATH
799 nh->nh_weight = 1;
800 #endif
801 }
802
803 if (fib_props[cfg->fc_type].error) {
804 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
805 goto err_inval;
806 goto link_it;
807 }
808
809 if (cfg->fc_scope > RT_SCOPE_HOST)
810 goto err_inval;
811
812 if (cfg->fc_scope == RT_SCOPE_HOST) {
813 struct fib_nh *nh = fi->fib_nh;
814
815 /* Local address is added. */
816 if (nhs != 1 || nh->nh_gw)
817 goto err_inval;
818 nh->nh_scope = RT_SCOPE_NOWHERE;
819 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
820 err = -ENODEV;
821 if (nh->nh_dev == NULL)
822 goto failure;
823 } else {
824 change_nexthops(fi) {
825 err = fib_check_nh(cfg, fi, nexthop_nh);
826 if (err != 0)
827 goto failure;
828 } endfor_nexthops(fi)
829 }
830
831 if (fi->fib_prefsrc) {
832 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
833 fi->fib_prefsrc != cfg->fc_dst)
834 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
835 goto err_inval;
836 }
837
838 link_it:
839 ofi = fib_find_info(fi);
840 if (ofi) {
841 fi->fib_dead = 1;
842 free_fib_info(fi);
843 ofi->fib_treeref++;
844 return ofi;
845 }
846
847 fi->fib_treeref++;
848 atomic_inc(&fi->fib_clntref);
849 spin_lock_bh(&fib_info_lock);
850 hlist_add_head(&fi->fib_hash,
851 &fib_info_hash[fib_info_hashfn(fi)]);
852 if (fi->fib_prefsrc) {
853 struct hlist_head *head;
854
855 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
856 hlist_add_head(&fi->fib_lhash, head);
857 }
858 change_nexthops(fi) {
859 struct hlist_head *head;
860 unsigned int hash;
861
862 if (!nexthop_nh->nh_dev)
863 continue;
864 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
865 head = &fib_info_devhash[hash];
866 hlist_add_head(&nexthop_nh->nh_hash, head);
867 } endfor_nexthops(fi)
868 spin_unlock_bh(&fib_info_lock);
869 return fi;
870
871 err_inval:
872 err = -EINVAL;
873
874 failure:
875 if (fi) {
876 fi->fib_dead = 1;
877 free_fib_info(fi);
878 }
879
880 return ERR_PTR(err);
881 }
882
883 /* Note! fib_semantic_match intentionally uses RCU list functions. */
884 int fib_semantic_match(struct list_head *head, const struct flowi *flp,
885 struct fib_result *res, int prefixlen, int fib_flags)
886 {
887 struct fib_alias *fa;
888 int nh_sel = 0;
889
890 list_for_each_entry_rcu(fa, head, fa_list) {
891 int err;
892
893 if (fa->fa_tos &&
894 fa->fa_tos != flp->fl4_tos)
895 continue;
896
897 if (fa->fa_scope < flp->fl4_scope)
898 continue;
899
900 fib_alias_accessed(fa);
901
902 err = fib_props[fa->fa_type].error;
903 if (err == 0) {
904 struct fib_info *fi = fa->fa_info;
905
906 if (fi->fib_flags & RTNH_F_DEAD)
907 continue;
908
909 switch (fa->fa_type) {
910 case RTN_UNICAST:
911 case RTN_LOCAL:
912 case RTN_BROADCAST:
913 case RTN_ANYCAST:
914 case RTN_MULTICAST:
915 for_nexthops(fi) {
916 if (nh->nh_flags & RTNH_F_DEAD)
917 continue;
918 if (!flp->oif || flp->oif == nh->nh_oif)
919 break;
920 }
921 #ifdef CONFIG_IP_ROUTE_MULTIPATH
922 if (nhsel < fi->fib_nhs) {
923 nh_sel = nhsel;
924 goto out_fill_res;
925 }
926 #else
927 if (nhsel < 1)
928 goto out_fill_res;
929 #endif
930 endfor_nexthops(fi);
931 continue;
932
933 default:
934 pr_warning("fib_semantic_match bad type %#x\n",
935 fa->fa_type);
936 return -EINVAL;
937 }
938 }
939 return err;
940 }
941 return 1;
942
943 out_fill_res:
944 res->prefixlen = prefixlen;
945 res->nh_sel = nh_sel;
946 res->type = fa->fa_type;
947 res->scope = fa->fa_scope;
948 res->fi = fa->fa_info;
949 if (!(fib_flags & FIB_LOOKUP_NOREF))
950 atomic_inc(&res->fi->fib_clntref);
951 return 0;
952 }
953
954 /* Find appropriate source address to this destination */
955
956 __be32 __fib_res_prefsrc(struct fib_result *res)
957 {
958 return inet_select_addr(FIB_RES_DEV(*res), FIB_RES_GW(*res), res->scope);
959 }
960
961 int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
962 u32 tb_id, u8 type, u8 scope, __be32 dst, int dst_len, u8 tos,
963 struct fib_info *fi, unsigned int flags)
964 {
965 struct nlmsghdr *nlh;
966 struct rtmsg *rtm;
967
968 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
969 if (nlh == NULL)
970 return -EMSGSIZE;
971
972 rtm = nlmsg_data(nlh);
973 rtm->rtm_family = AF_INET;
974 rtm->rtm_dst_len = dst_len;
975 rtm->rtm_src_len = 0;
976 rtm->rtm_tos = tos;
977 if (tb_id < 256)
978 rtm->rtm_table = tb_id;
979 else
980 rtm->rtm_table = RT_TABLE_COMPAT;
981 NLA_PUT_U32(skb, RTA_TABLE, tb_id);
982 rtm->rtm_type = type;
983 rtm->rtm_flags = fi->fib_flags;
984 rtm->rtm_scope = scope;
985 rtm->rtm_protocol = fi->fib_protocol;
986
987 if (rtm->rtm_dst_len)
988 NLA_PUT_BE32(skb, RTA_DST, dst);
989
990 if (fi->fib_priority)
991 NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
992
993 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
994 goto nla_put_failure;
995
996 if (fi->fib_prefsrc)
997 NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc);
998
999 if (fi->fib_nhs == 1) {
1000 if (fi->fib_nh->nh_gw)
1001 NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
1002
1003 if (fi->fib_nh->nh_oif)
1004 NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
1005 #ifdef CONFIG_NET_CLS_ROUTE
1006 if (fi->fib_nh[0].nh_tclassid)
1007 NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
1008 #endif
1009 }
1010 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1011 if (fi->fib_nhs > 1) {
1012 struct rtnexthop *rtnh;
1013 struct nlattr *mp;
1014
1015 mp = nla_nest_start(skb, RTA_MULTIPATH);
1016 if (mp == NULL)
1017 goto nla_put_failure;
1018
1019 for_nexthops(fi) {
1020 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1021 if (rtnh == NULL)
1022 goto nla_put_failure;
1023
1024 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1025 rtnh->rtnh_hops = nh->nh_weight - 1;
1026 rtnh->rtnh_ifindex = nh->nh_oif;
1027
1028 if (nh->nh_gw)
1029 NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw);
1030 #ifdef CONFIG_NET_CLS_ROUTE
1031 if (nh->nh_tclassid)
1032 NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
1033 #endif
1034 /* length of rtnetlink header + attributes */
1035 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1036 } endfor_nexthops(fi);
1037
1038 nla_nest_end(skb, mp);
1039 }
1040 #endif
1041 return nlmsg_end(skb, nlh);
1042
1043 nla_put_failure:
1044 nlmsg_cancel(skb, nlh);
1045 return -EMSGSIZE;
1046 }
1047
1048 /*
1049 * Update FIB if:
1050 * - local address disappeared -> we must delete all the entries
1051 * referring to it.
1052 * - device went down -> we must shutdown all nexthops going via it.
1053 */
1054 int fib_sync_down_addr(struct net *net, __be32 local)
1055 {
1056 int ret = 0;
1057 unsigned int hash = fib_laddr_hashfn(local);
1058 struct hlist_head *head = &fib_info_laddrhash[hash];
1059 struct hlist_node *node;
1060 struct fib_info *fi;
1061
1062 if (fib_info_laddrhash == NULL || local == 0)
1063 return 0;
1064
1065 hlist_for_each_entry(fi, node, head, fib_lhash) {
1066 if (!net_eq(fi->fib_net, net))
1067 continue;
1068 if (fi->fib_prefsrc == local) {
1069 fi->fib_flags |= RTNH_F_DEAD;
1070 ret++;
1071 }
1072 }
1073 return ret;
1074 }
1075
1076 int fib_sync_down_dev(struct net_device *dev, int force)
1077 {
1078 int ret = 0;
1079 int scope = RT_SCOPE_NOWHERE;
1080 struct fib_info *prev_fi = NULL;
1081 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1082 struct hlist_head *head = &fib_info_devhash[hash];
1083 struct hlist_node *node;
1084 struct fib_nh *nh;
1085
1086 if (force)
1087 scope = -1;
1088
1089 hlist_for_each_entry(nh, node, head, nh_hash) {
1090 struct fib_info *fi = nh->nh_parent;
1091 int dead;
1092
1093 BUG_ON(!fi->fib_nhs);
1094 if (nh->nh_dev != dev || fi == prev_fi)
1095 continue;
1096 prev_fi = fi;
1097 dead = 0;
1098 change_nexthops(fi) {
1099 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1100 dead++;
1101 else if (nexthop_nh->nh_dev == dev &&
1102 nexthop_nh->nh_scope != scope) {
1103 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1104 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1105 spin_lock_bh(&fib_multipath_lock);
1106 fi->fib_power -= nexthop_nh->nh_power;
1107 nexthop_nh->nh_power = 0;
1108 spin_unlock_bh(&fib_multipath_lock);
1109 #endif
1110 dead++;
1111 }
1112 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1113 if (force > 1 && nexthop_nh->nh_dev == dev) {
1114 dead = fi->fib_nhs;
1115 break;
1116 }
1117 #endif
1118 } endfor_nexthops(fi)
1119 if (dead == fi->fib_nhs) {
1120 fi->fib_flags |= RTNH_F_DEAD;
1121 ret++;
1122 }
1123 }
1124
1125 return ret;
1126 }
1127
1128 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1129
1130 /*
1131 * Dead device goes up. We wake up dead nexthops.
1132 * It takes sense only on multipath routes.
1133 */
1134 int fib_sync_up(struct net_device *dev)
1135 {
1136 struct fib_info *prev_fi;
1137 unsigned int hash;
1138 struct hlist_head *head;
1139 struct hlist_node *node;
1140 struct fib_nh *nh;
1141 int ret;
1142
1143 if (!(dev->flags & IFF_UP))
1144 return 0;
1145
1146 prev_fi = NULL;
1147 hash = fib_devindex_hashfn(dev->ifindex);
1148 head = &fib_info_devhash[hash];
1149 ret = 0;
1150
1151 hlist_for_each_entry(nh, node, head, nh_hash) {
1152 struct fib_info *fi = nh->nh_parent;
1153 int alive;
1154
1155 BUG_ON(!fi->fib_nhs);
1156 if (nh->nh_dev != dev || fi == prev_fi)
1157 continue;
1158
1159 prev_fi = fi;
1160 alive = 0;
1161 change_nexthops(fi) {
1162 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1163 alive++;
1164 continue;
1165 }
1166 if (nexthop_nh->nh_dev == NULL ||
1167 !(nexthop_nh->nh_dev->flags & IFF_UP))
1168 continue;
1169 if (nexthop_nh->nh_dev != dev ||
1170 !__in_dev_get_rtnl(dev))
1171 continue;
1172 alive++;
1173 spin_lock_bh(&fib_multipath_lock);
1174 nexthop_nh->nh_power = 0;
1175 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1176 spin_unlock_bh(&fib_multipath_lock);
1177 } endfor_nexthops(fi)
1178
1179 if (alive > 0) {
1180 fi->fib_flags &= ~RTNH_F_DEAD;
1181 ret++;
1182 }
1183 }
1184
1185 return ret;
1186 }
1187
1188 /*
1189 * The algorithm is suboptimal, but it provides really
1190 * fair weighted route distribution.
1191 */
1192 void fib_select_multipath(const struct flowi *flp, struct fib_result *res)
1193 {
1194 struct fib_info *fi = res->fi;
1195 int w;
1196
1197 spin_lock_bh(&fib_multipath_lock);
1198 if (fi->fib_power <= 0) {
1199 int power = 0;
1200 change_nexthops(fi) {
1201 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1202 power += nexthop_nh->nh_weight;
1203 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1204 }
1205 } endfor_nexthops(fi);
1206 fi->fib_power = power;
1207 if (power <= 0) {
1208 spin_unlock_bh(&fib_multipath_lock);
1209 /* Race condition: route has just become dead. */
1210 res->nh_sel = 0;
1211 return;
1212 }
1213 }
1214
1215
1216 /* w should be random number [0..fi->fib_power-1],
1217 * it is pretty bad approximation.
1218 */
1219
1220 w = jiffies % fi->fib_power;
1221
1222 change_nexthops(fi) {
1223 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1224 nexthop_nh->nh_power) {
1225 w -= nexthop_nh->nh_power;
1226 if (w <= 0) {
1227 nexthop_nh->nh_power--;
1228 fi->fib_power--;
1229 res->nh_sel = nhsel;
1230 spin_unlock_bh(&fib_multipath_lock);
1231 return;
1232 }
1233 }
1234 } endfor_nexthops(fi);
1235
1236 /* Race condition: route has just become dead. */
1237 res->nh_sel = 0;
1238 spin_unlock_bh(&fib_multipath_lock);
1239 }
1240 #endif
linux-next