projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx
[deliverable/linux.git] / net / ipv4 / fib_semantics.c
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_info_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 const struct fib_prop fib_props[RTN_MAX + 1] = {
94 [RTN_UNSPEC] = {
95 .error = 0,
96 .scope = RT_SCOPE_NOWHERE,
97 },
98 [RTN_UNICAST] = {
99 .error = 0,
100 .scope = RT_SCOPE_UNIVERSE,
101 },
102 [RTN_LOCAL] = {
103 .error = 0,
104 .scope = RT_SCOPE_HOST,
105 },
106 [RTN_BROADCAST] = {
107 .error = 0,
108 .scope = RT_SCOPE_LINK,
109 },
110 [RTN_ANYCAST] = {
111 .error = 0,
112 .scope = RT_SCOPE_LINK,
113 },
114 [RTN_MULTICAST] = {
115 .error = 0,
116 .scope = RT_SCOPE_UNIVERSE,
117 },
118 [RTN_BLACKHOLE] = {
119 .error = -EINVAL,
120 .scope = RT_SCOPE_UNIVERSE,
121 },
122 [RTN_UNREACHABLE] = {
123 .error = -EHOSTUNREACH,
124 .scope = RT_SCOPE_UNIVERSE,
125 },
126 [RTN_PROHIBIT] = {
127 .error = -EACCES,
128 .scope = RT_SCOPE_UNIVERSE,
129 },
130 [RTN_THROW] = {
131 .error = -EAGAIN,
132 .scope = RT_SCOPE_UNIVERSE,
133 },
134 [RTN_NAT] = {
135 .error = -EINVAL,
136 .scope = RT_SCOPE_NOWHERE,
137 },
138 [RTN_XRESOLVE] = {
139 .error = -EINVAL,
140 .scope = RT_SCOPE_NOWHERE,
141 },
142 };
143
144
145 /* Release a nexthop info record */
146
147 static void free_fib_info_rcu(struct rcu_head *head)
148 {
149 struct fib_info *fi = container_of(head, struct fib_info, rcu);
150
151 if (fi->fib_metrics != (u32 *) dst_default_metrics)
152 kfree(fi->fib_metrics);
153 kfree(fi);
154 }
155
156 void free_fib_info(struct fib_info *fi)
157 {
158 if (fi->fib_dead == 0) {
159 pr_warning("Freeing alive fib_info %p\n", fi);
160 return;
161 }
162 change_nexthops(fi) {
163 if (nexthop_nh->nh_dev)
164 dev_put(nexthop_nh->nh_dev);
165 nexthop_nh->nh_dev = NULL;
166 } endfor_nexthops(fi);
167 fib_info_cnt--;
168 release_net(fi->fib_net);
169 call_rcu(&fi->rcu, free_fib_info_rcu);
170 }
171
172 void fib_release_info(struct fib_info *fi)
173 {
174 spin_lock_bh(&fib_info_lock);
175 if (fi && --fi->fib_treeref == 0) {
176 hlist_del(&fi->fib_hash);
177 if (fi->fib_prefsrc)
178 hlist_del(&fi->fib_lhash);
179 change_nexthops(fi) {
180 if (!nexthop_nh->nh_dev)
181 continue;
182 hlist_del(&nexthop_nh->nh_hash);
183 } endfor_nexthops(fi)
184 fi->fib_dead = 1;
185 fib_info_put(fi);
186 }
187 spin_unlock_bh(&fib_info_lock);
188 }
189
190 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
191 {
192 const struct fib_nh *onh = ofi->fib_nh;
193
194 for_nexthops(fi) {
195 if (nh->nh_oif != onh->nh_oif ||
196 nh->nh_gw != onh->nh_gw ||
197 nh->nh_scope != onh->nh_scope ||
198 #ifdef CONFIG_IP_ROUTE_MULTIPATH
199 nh->nh_weight != onh->nh_weight ||
200 #endif
201 #ifdef CONFIG_IP_ROUTE_CLASSID
202 nh->nh_tclassid != onh->nh_tclassid ||
203 #endif
204 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
205 return -1;
206 onh++;
207 } endfor_nexthops(fi);
208 return 0;
209 }
210
211 static inline unsigned int fib_devindex_hashfn(unsigned int val)
212 {
213 unsigned int mask = DEVINDEX_HASHSIZE - 1;
214
215 return (val ^
216 (val >> DEVINDEX_HASHBITS) ^
217 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
218 }
219
220 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
221 {
222 unsigned int mask = (fib_info_hash_size - 1);
223 unsigned int val = fi->fib_nhs;
224
225 val ^= fi->fib_protocol;
226 val ^= (__force u32)fi->fib_prefsrc;
227 val ^= fi->fib_priority;
228 for_nexthops(fi) {
229 val ^= fib_devindex_hashfn(nh->nh_oif);
230 } endfor_nexthops(fi)
231
232 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
233 }
234
235 static struct fib_info *fib_find_info(const struct fib_info *nfi)
236 {
237 struct hlist_head *head;
238 struct hlist_node *node;
239 struct fib_info *fi;
240 unsigned int hash;
241
242 hash = fib_info_hashfn(nfi);
243 head = &fib_info_hash[hash];
244
245 hlist_for_each_entry(fi, node, head, fib_hash) {
246 if (!net_eq(fi->fib_net, nfi->fib_net))
247 continue;
248 if (fi->fib_nhs != nfi->fib_nhs)
249 continue;
250 if (nfi->fib_protocol == fi->fib_protocol &&
251 nfi->fib_prefsrc == fi->fib_prefsrc &&
252 nfi->fib_priority == fi->fib_priority &&
253 memcmp(nfi->fib_metrics, fi->fib_metrics,
254 sizeof(fi->fib_metrics)) == 0 &&
255 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
256 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
257 return fi;
258 }
259
260 return NULL;
261 }
262
263 /* Check, that the gateway is already configured.
264 * Used only by redirect accept routine.
265 */
266 int ip_fib_check_default(__be32 gw, struct net_device *dev)
267 {
268 struct hlist_head *head;
269 struct hlist_node *node;
270 struct fib_nh *nh;
271 unsigned int hash;
272
273 spin_lock(&fib_info_lock);
274
275 hash = fib_devindex_hashfn(dev->ifindex);
276 head = &fib_info_devhash[hash];
277 hlist_for_each_entry(nh, node, head, nh_hash) {
278 if (nh->nh_dev == dev &&
279 nh->nh_gw == gw &&
280 !(nh->nh_flags & RTNH_F_DEAD)) {
281 spin_unlock(&fib_info_lock);
282 return 0;
283 }
284 }
285
286 spin_unlock(&fib_info_lock);
287
288 return -1;
289 }
290
291 static inline size_t fib_nlmsg_size(struct fib_info *fi)
292 {
293 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
294 + nla_total_size(4) /* RTA_TABLE */
295 + nla_total_size(4) /* RTA_DST */
296 + nla_total_size(4) /* RTA_PRIORITY */
297 + nla_total_size(4); /* RTA_PREFSRC */
298
299 /* space for nested metrics */
300 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
301
302 if (fi->fib_nhs) {
303 /* Also handles the special case fib_nhs == 1 */
304
305 /* each nexthop is packed in an attribute */
306 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
307
308 /* may contain flow and gateway attribute */
309 nhsize += 2 * nla_total_size(4);
310
311 /* all nexthops are packed in a nested attribute */
312 payload += nla_total_size(fi->fib_nhs * nhsize);
313 }
314
315 return payload;
316 }
317
318 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
319 int dst_len, u32 tb_id, struct nl_info *info,
320 unsigned int nlm_flags)
321 {
322 struct sk_buff *skb;
323 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
324 int err = -ENOBUFS;
325
326 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
327 if (skb == NULL)
328 goto errout;
329
330 err = fib_dump_info(skb, info->pid, seq, event, tb_id,
331 fa->fa_type, fa->fa_scope, key, dst_len,
332 fa->fa_tos, fa->fa_info, nlm_flags);
333 if (err < 0) {
334 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
335 WARN_ON(err == -EMSGSIZE);
336 kfree_skb(skb);
337 goto errout;
338 }
339 rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
340 info->nlh, GFP_KERNEL);
341 return;
342 errout:
343 if (err < 0)
344 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
345 }
346
347 /* Return the first fib alias matching TOS with
348 * priority less than or equal to PRIO.
349 */
350 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
351 {
352 if (fah) {
353 struct fib_alias *fa;
354 list_for_each_entry(fa, fah, fa_list) {
355 if (fa->fa_tos > tos)
356 continue;
357 if (fa->fa_info->fib_priority >= prio ||
358 fa->fa_tos < tos)
359 return fa;
360 }
361 }
362 return NULL;
363 }
364
365 int fib_detect_death(struct fib_info *fi, int order,
366 struct fib_info **last_resort, int *last_idx, int dflt)
367 {
368 struct neighbour *n;
369 int state = NUD_NONE;
370
371 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
372 if (n) {
373 state = n->nud_state;
374 neigh_release(n);
375 }
376 if (state == NUD_REACHABLE)
377 return 0;
378 if ((state & NUD_VALID) && order != dflt)
379 return 0;
380 if ((state & NUD_VALID) ||
381 (*last_idx < 0 && order > dflt)) {
382 *last_resort = fi;
383 *last_idx = order;
384 }
385 return 1;
386 }
387
388 #ifdef CONFIG_IP_ROUTE_MULTIPATH
389
390 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
391 {
392 int nhs = 0;
393
394 while (rtnh_ok(rtnh, remaining)) {
395 nhs++;
396 rtnh = rtnh_next(rtnh, &remaining);
397 }
398
399 /* leftover implies invalid nexthop configuration, discard it */
400 return remaining > 0 ? 0 : nhs;
401 }
402
403 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
404 int remaining, struct fib_config *cfg)
405 {
406 change_nexthops(fi) {
407 int attrlen;
408
409 if (!rtnh_ok(rtnh, remaining))
410 return -EINVAL;
411
412 nexthop_nh->nh_flags =
413 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
414 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
415 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
416
417 attrlen = rtnh_attrlen(rtnh);
418 if (attrlen > 0) {
419 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
420
421 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
422 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
423 #ifdef CONFIG_IP_ROUTE_CLASSID
424 nla = nla_find(attrs, attrlen, RTA_FLOW);
425 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
426 #endif
427 }
428
429 rtnh = rtnh_next(rtnh, &remaining);
430 } endfor_nexthops(fi);
431
432 return 0;
433 }
434
435 #endif
436
437 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
438 {
439 #ifdef CONFIG_IP_ROUTE_MULTIPATH
440 struct rtnexthop *rtnh;
441 int remaining;
442 #endif
443
444 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
445 return 1;
446
447 if (cfg->fc_oif || cfg->fc_gw) {
448 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
449 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
450 return 0;
451 return 1;
452 }
453
454 #ifdef CONFIG_IP_ROUTE_MULTIPATH
455 if (cfg->fc_mp == NULL)
456 return 0;
457
458 rtnh = cfg->fc_mp;
459 remaining = cfg->fc_mp_len;
460
461 for_nexthops(fi) {
462 int attrlen;
463
464 if (!rtnh_ok(rtnh, remaining))
465 return -EINVAL;
466
467 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
468 return 1;
469
470 attrlen = rtnh_attrlen(rtnh);
471 if (attrlen < 0) {
472 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
473
474 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
475 if (nla && nla_get_be32(nla) != nh->nh_gw)
476 return 1;
477 #ifdef CONFIG_IP_ROUTE_CLASSID
478 nla = nla_find(attrs, attrlen, RTA_FLOW);
479 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
480 return 1;
481 #endif
482 }
483
484 rtnh = rtnh_next(rtnh, &remaining);
485 } endfor_nexthops(fi);
486 #endif
487 return 0;
488 }
489
490
491 /*
492 * Picture
493 * -------
494 *
495 * Semantics of nexthop is very messy by historical reasons.
496 * We have to take into account, that:
497 * a) gateway can be actually local interface address,
498 * so that gatewayed route is direct.
499 * b) gateway must be on-link address, possibly
500 * described not by an ifaddr, but also by a direct route.
501 * c) If both gateway and interface are specified, they should not
502 * contradict.
503 * d) If we use tunnel routes, gateway could be not on-link.
504 *
505 * Attempt to reconcile all of these (alas, self-contradictory) conditions
506 * results in pretty ugly and hairy code with obscure logic.
507 *
508 * I chose to generalized it instead, so that the size
509 * of code does not increase practically, but it becomes
510 * much more general.
511 * Every prefix is assigned a "scope" value: "host" is local address,
512 * "link" is direct route,
513 * [ ... "site" ... "interior" ... ]
514 * and "universe" is true gateway route with global meaning.
515 *
516 * Every prefix refers to a set of "nexthop"s (gw, oif),
517 * where gw must have narrower scope. This recursion stops
518 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
519 * which means that gw is forced to be on link.
520 *
521 * Code is still hairy, but now it is apparently logically
522 * consistent and very flexible. F.e. as by-product it allows
523 * to co-exists in peace independent exterior and interior
524 * routing processes.
525 *
526 * Normally it looks as following.
527 *
528 * {universe prefix} -> (gw, oif) [scope link]
529 * |
530 * |-> {link prefix} -> (gw, oif) [scope local]
531 * |
532 * |-> {local prefix} (terminal node)
533 */
534 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
535 struct fib_nh *nh)
536 {
537 int err;
538 struct net *net;
539 struct net_device *dev;
540
541 net = cfg->fc_nlinfo.nl_net;
542 if (nh->nh_gw) {
543 struct fib_result res;
544
545 if (nh->nh_flags & RTNH_F_ONLINK) {
546
547 if (cfg->fc_scope >= RT_SCOPE_LINK)
548 return -EINVAL;
549 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
550 return -EINVAL;
551 dev = __dev_get_by_index(net, nh->nh_oif);
552 if (!dev)
553 return -ENODEV;
554 if (!(dev->flags & IFF_UP))
555 return -ENETDOWN;
556 nh->nh_dev = dev;
557 dev_hold(dev);
558 nh->nh_scope = RT_SCOPE_LINK;
559 return 0;
560 }
561 rcu_read_lock();
562 {
563 struct flowi4 fl4 = {
564 .daddr = nh->nh_gw,
565 .flowi4_scope = cfg->fc_scope + 1,
566 .flowi4_oif = nh->nh_oif,
567 };
568
569 /* It is not necessary, but requires a bit of thinking */
570 if (fl4.flowi4_scope < RT_SCOPE_LINK)
571 fl4.flowi4_scope = RT_SCOPE_LINK;
572 err = fib_lookup(net, &fl4, &res);
573 if (err) {
574 rcu_read_unlock();
575 return err;
576 }
577 }
578 err = -EINVAL;
579 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
580 goto out;
581 nh->nh_scope = res.scope;
582 nh->nh_oif = FIB_RES_OIF(res);
583 nh->nh_dev = dev = FIB_RES_DEV(res);
584 if (!dev)
585 goto out;
586 dev_hold(dev);
587 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
588 } else {
589 struct in_device *in_dev;
590
591 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
592 return -EINVAL;
593
594 rcu_read_lock();
595 err = -ENODEV;
596 in_dev = inetdev_by_index(net, nh->nh_oif);
597 if (in_dev == NULL)
598 goto out;
599 err = -ENETDOWN;
600 if (!(in_dev->dev->flags & IFF_UP))
601 goto out;
602 nh->nh_dev = in_dev->dev;
603 dev_hold(nh->nh_dev);
604 nh->nh_scope = RT_SCOPE_HOST;
605 err = 0;
606 }
607 out:
608 rcu_read_unlock();
609 return err;
610 }
611
612 static inline unsigned int fib_laddr_hashfn(__be32 val)
613 {
614 unsigned int mask = (fib_info_hash_size - 1);
615
616 return ((__force u32)val ^
617 ((__force u32)val >> 7) ^
618 ((__force u32)val >> 14)) & mask;
619 }
620
621 static struct hlist_head *fib_info_hash_alloc(int bytes)
622 {
623 if (bytes <= PAGE_SIZE)
624 return kzalloc(bytes, GFP_KERNEL);
625 else
626 return (struct hlist_head *)
627 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
628 get_order(bytes));
629 }
630
631 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
632 {
633 if (!hash)
634 return;
635
636 if (bytes <= PAGE_SIZE)
637 kfree(hash);
638 else
639 free_pages((unsigned long) hash, get_order(bytes));
640 }
641
642 static void fib_info_hash_move(struct hlist_head *new_info_hash,
643 struct hlist_head *new_laddrhash,
644 unsigned int new_size)
645 {
646 struct hlist_head *old_info_hash, *old_laddrhash;
647 unsigned int old_size = fib_info_hash_size;
648 unsigned int i, bytes;
649
650 spin_lock_bh(&fib_info_lock);
651 old_info_hash = fib_info_hash;
652 old_laddrhash = fib_info_laddrhash;
653 fib_info_hash_size = new_size;
654
655 for (i = 0; i < old_size; i++) {
656 struct hlist_head *head = &fib_info_hash[i];
657 struct hlist_node *node, *n;
658 struct fib_info *fi;
659
660 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
661 struct hlist_head *dest;
662 unsigned int new_hash;
663
664 hlist_del(&fi->fib_hash);
665
666 new_hash = fib_info_hashfn(fi);
667 dest = &new_info_hash[new_hash];
668 hlist_add_head(&fi->fib_hash, dest);
669 }
670 }
671 fib_info_hash = new_info_hash;
672
673 for (i = 0; i < old_size; i++) {
674 struct hlist_head *lhead = &fib_info_laddrhash[i];
675 struct hlist_node *node, *n;
676 struct fib_info *fi;
677
678 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
679 struct hlist_head *ldest;
680 unsigned int new_hash;
681
682 hlist_del(&fi->fib_lhash);
683
684 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
685 ldest = &new_laddrhash[new_hash];
686 hlist_add_head(&fi->fib_lhash, ldest);
687 }
688 }
689 fib_info_laddrhash = new_laddrhash;
690
691 spin_unlock_bh(&fib_info_lock);
692
693 bytes = old_size * sizeof(struct hlist_head *);
694 fib_info_hash_free(old_info_hash, bytes);
695 fib_info_hash_free(old_laddrhash, bytes);
696 }
697
698 struct fib_info *fib_create_info(struct fib_config *cfg)
699 {
700 int err;
701 struct fib_info *fi = NULL;
702 struct fib_info *ofi;
703 int nhs = 1;
704 struct net *net = cfg->fc_nlinfo.nl_net;
705
706 if (cfg->fc_type > RTN_MAX)
707 goto err_inval;
708
709 /* Fast check to catch the most weird cases */
710 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
711 goto err_inval;
712
713 #ifdef CONFIG_IP_ROUTE_MULTIPATH
714 if (cfg->fc_mp) {
715 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
716 if (nhs == 0)
717 goto err_inval;
718 }
719 #endif
720
721 err = -ENOBUFS;
722 if (fib_info_cnt >= fib_info_hash_size) {
723 unsigned int new_size = fib_info_hash_size << 1;
724 struct hlist_head *new_info_hash;
725 struct hlist_head *new_laddrhash;
726 unsigned int bytes;
727
728 if (!new_size)
729 new_size = 1;
730 bytes = new_size * sizeof(struct hlist_head *);
731 new_info_hash = fib_info_hash_alloc(bytes);
732 new_laddrhash = fib_info_hash_alloc(bytes);
733 if (!new_info_hash || !new_laddrhash) {
734 fib_info_hash_free(new_info_hash, bytes);
735 fib_info_hash_free(new_laddrhash, bytes);
736 } else
737 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
738
739 if (!fib_info_hash_size)
740 goto failure;
741 }
742
743 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
744 if (fi == NULL)
745 goto failure;
746 if (cfg->fc_mx) {
747 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
748 if (!fi->fib_metrics)
749 goto failure;
750 } else
751 fi->fib_metrics = (u32 *) dst_default_metrics;
752 fib_info_cnt++;
753
754 fi->fib_net = hold_net(net);
755 fi->fib_protocol = cfg->fc_protocol;
756 fi->fib_flags = cfg->fc_flags;
757 fi->fib_priority = cfg->fc_priority;
758 fi->fib_prefsrc = cfg->fc_prefsrc;
759
760 fi->fib_nhs = nhs;
761 change_nexthops(fi) {
762 nexthop_nh->nh_parent = fi;
763 } endfor_nexthops(fi)
764
765 if (cfg->fc_mx) {
766 struct nlattr *nla;
767 int remaining;
768
769 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
770 int type = nla_type(nla);
771
772 if (type) {
773 if (type > RTAX_MAX)
774 goto err_inval;
775 fi->fib_metrics[type - 1] = nla_get_u32(nla);
776 }
777 }
778 }
779
780 if (cfg->fc_mp) {
781 #ifdef CONFIG_IP_ROUTE_MULTIPATH
782 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
783 if (err != 0)
784 goto failure;
785 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
786 goto err_inval;
787 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
788 goto err_inval;
789 #ifdef CONFIG_IP_ROUTE_CLASSID
790 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
791 goto err_inval;
792 #endif
793 #else
794 goto err_inval;
795 #endif
796 } else {
797 struct fib_nh *nh = fi->fib_nh;
798
799 nh->nh_oif = cfg->fc_oif;
800 nh->nh_gw = cfg->fc_gw;
801 nh->nh_flags = cfg->fc_flags;
802 #ifdef CONFIG_IP_ROUTE_CLASSID
803 nh->nh_tclassid = cfg->fc_flow;
804 #endif
805 #ifdef CONFIG_IP_ROUTE_MULTIPATH
806 nh->nh_weight = 1;
807 #endif
808 }
809
810 if (fib_props[cfg->fc_type].error) {
811 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
812 goto err_inval;
813 goto link_it;
814 } else {
815 switch (cfg->fc_type) {
816 case RTN_UNICAST:
817 case RTN_LOCAL:
818 case RTN_BROADCAST:
819 case RTN_ANYCAST:
820 case RTN_MULTICAST:
821 break;
822 default:
823 goto err_inval;
824 }
825 }
826
827 if (cfg->fc_scope > RT_SCOPE_HOST)
828 goto err_inval;
829
830 if (cfg->fc_scope == RT_SCOPE_HOST) {
831 struct fib_nh *nh = fi->fib_nh;
832
833 /* Local address is added. */
834 if (nhs != 1 || nh->nh_gw)
835 goto err_inval;
836 nh->nh_scope = RT_SCOPE_NOWHERE;
837 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
838 err = -ENODEV;
839 if (nh->nh_dev == NULL)
840 goto failure;
841 } else {
842 change_nexthops(fi) {
843 err = fib_check_nh(cfg, fi, nexthop_nh);
844 if (err != 0)
845 goto failure;
846 } endfor_nexthops(fi)
847 }
848
849 if (fi->fib_prefsrc) {
850 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
851 fi->fib_prefsrc != cfg->fc_dst)
852 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
853 goto err_inval;
854 }
855
856 change_nexthops(fi) {
857 nexthop_nh->nh_cfg_scope = cfg->fc_scope;
858 nexthop_nh->nh_saddr = inet_select_addr(nexthop_nh->nh_dev,
859 nexthop_nh->nh_gw,
860 nexthop_nh->nh_cfg_scope);
861 } endfor_nexthops(fi)
862
863 link_it:
864 ofi = fib_find_info(fi);
865 if (ofi) {
866 fi->fib_dead = 1;
867 free_fib_info(fi);
868 ofi->fib_treeref++;
869 return ofi;
870 }
871
872 fi->fib_treeref++;
873 atomic_inc(&fi->fib_clntref);
874 spin_lock_bh(&fib_info_lock);
875 hlist_add_head(&fi->fib_hash,
876 &fib_info_hash[fib_info_hashfn(fi)]);
877 if (fi->fib_prefsrc) {
878 struct hlist_head *head;
879
880 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
881 hlist_add_head(&fi->fib_lhash, head);
882 }
883 change_nexthops(fi) {
884 struct hlist_head *head;
885 unsigned int hash;
886
887 if (!nexthop_nh->nh_dev)
888 continue;
889 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
890 head = &fib_info_devhash[hash];
891 hlist_add_head(&nexthop_nh->nh_hash, head);
892 } endfor_nexthops(fi)
893 spin_unlock_bh(&fib_info_lock);
894 return fi;
895
896 err_inval:
897 err = -EINVAL;
898
899 failure:
900 if (fi) {
901 fi->fib_dead = 1;
902 free_fib_info(fi);
903 }
904
905 return ERR_PTR(err);
906 }
907
908 int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
909 u32 tb_id, u8 type, u8 scope, __be32 dst, int dst_len, u8 tos,
910 struct fib_info *fi, unsigned int flags)
911 {
912 struct nlmsghdr *nlh;
913 struct rtmsg *rtm;
914
915 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
916 if (nlh == NULL)
917 return -EMSGSIZE;
918
919 rtm = nlmsg_data(nlh);
920 rtm->rtm_family = AF_INET;
921 rtm->rtm_dst_len = dst_len;
922 rtm->rtm_src_len = 0;
923 rtm->rtm_tos = tos;
924 if (tb_id < 256)
925 rtm->rtm_table = tb_id;
926 else
927 rtm->rtm_table = RT_TABLE_COMPAT;
928 NLA_PUT_U32(skb, RTA_TABLE, tb_id);
929 rtm->rtm_type = type;
930 rtm->rtm_flags = fi->fib_flags;
931 rtm->rtm_scope = scope;
932 rtm->rtm_protocol = fi->fib_protocol;
933
934 if (rtm->rtm_dst_len)
935 NLA_PUT_BE32(skb, RTA_DST, dst);
936
937 if (fi->fib_priority)
938 NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
939
940 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
941 goto nla_put_failure;
942
943 if (fi->fib_prefsrc)
944 NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc);
945
946 if (fi->fib_nhs == 1) {
947 if (fi->fib_nh->nh_gw)
948 NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
949
950 if (fi->fib_nh->nh_oif)
951 NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
952 #ifdef CONFIG_IP_ROUTE_CLASSID
953 if (fi->fib_nh[0].nh_tclassid)
954 NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
955 #endif
956 }
957 #ifdef CONFIG_IP_ROUTE_MULTIPATH
958 if (fi->fib_nhs > 1) {
959 struct rtnexthop *rtnh;
960 struct nlattr *mp;
961
962 mp = nla_nest_start(skb, RTA_MULTIPATH);
963 if (mp == NULL)
964 goto nla_put_failure;
965
966 for_nexthops(fi) {
967 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
968 if (rtnh == NULL)
969 goto nla_put_failure;
970
971 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
972 rtnh->rtnh_hops = nh->nh_weight - 1;
973 rtnh->rtnh_ifindex = nh->nh_oif;
974
975 if (nh->nh_gw)
976 NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw);
977 #ifdef CONFIG_IP_ROUTE_CLASSID
978 if (nh->nh_tclassid)
979 NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
980 #endif
981 /* length of rtnetlink header + attributes */
982 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
983 } endfor_nexthops(fi);
984
985 nla_nest_end(skb, mp);
986 }
987 #endif
988 return nlmsg_end(skb, nlh);
989
990 nla_put_failure:
991 nlmsg_cancel(skb, nlh);
992 return -EMSGSIZE;
993 }
994
995 /*
996 * Update FIB if:
997 * - local address disappeared -> we must delete all the entries
998 * referring to it.
999 * - device went down -> we must shutdown all nexthops going via it.
1000 */
1001 int fib_sync_down_addr(struct net *net, __be32 local)
1002 {
1003 int ret = 0;
1004 unsigned int hash = fib_laddr_hashfn(local);
1005 struct hlist_head *head = &fib_info_laddrhash[hash];
1006 struct hlist_node *node;
1007 struct fib_info *fi;
1008
1009 if (fib_info_laddrhash == NULL || local == 0)
1010 return 0;
1011
1012 hlist_for_each_entry(fi, node, head, fib_lhash) {
1013 if (!net_eq(fi->fib_net, net))
1014 continue;
1015 if (fi->fib_prefsrc == local) {
1016 fi->fib_flags |= RTNH_F_DEAD;
1017 ret++;
1018 }
1019 }
1020 return ret;
1021 }
1022
1023 int fib_sync_down_dev(struct net_device *dev, int force)
1024 {
1025 int ret = 0;
1026 int scope = RT_SCOPE_NOWHERE;
1027 struct fib_info *prev_fi = NULL;
1028 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1029 struct hlist_head *head = &fib_info_devhash[hash];
1030 struct hlist_node *node;
1031 struct fib_nh *nh;
1032
1033 if (force)
1034 scope = -1;
1035
1036 hlist_for_each_entry(nh, node, head, nh_hash) {
1037 struct fib_info *fi = nh->nh_parent;
1038 int dead;
1039
1040 BUG_ON(!fi->fib_nhs);
1041 if (nh->nh_dev != dev || fi == prev_fi)
1042 continue;
1043 prev_fi = fi;
1044 dead = 0;
1045 change_nexthops(fi) {
1046 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1047 dead++;
1048 else if (nexthop_nh->nh_dev == dev &&
1049 nexthop_nh->nh_scope != scope) {
1050 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1051 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1052 spin_lock_bh(&fib_multipath_lock);
1053 fi->fib_power -= nexthop_nh->nh_power;
1054 nexthop_nh->nh_power = 0;
1055 spin_unlock_bh(&fib_multipath_lock);
1056 #endif
1057 dead++;
1058 }
1059 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1060 if (force > 1 && nexthop_nh->nh_dev == dev) {
1061 dead = fi->fib_nhs;
1062 break;
1063 }
1064 #endif
1065 } endfor_nexthops(fi)
1066 if (dead == fi->fib_nhs) {
1067 fi->fib_flags |= RTNH_F_DEAD;
1068 ret++;
1069 }
1070 }
1071
1072 return ret;
1073 }
1074
1075 /* Must be invoked inside of an RCU protected region. */
1076 void fib_select_default(struct fib_result *res)
1077 {
1078 struct fib_info *fi = NULL, *last_resort = NULL;
1079 struct list_head *fa_head = res->fa_head;
1080 struct fib_table *tb = res->table;
1081 int order = -1, last_idx = -1;
1082 struct fib_alias *fa;
1083
1084 list_for_each_entry_rcu(fa, fa_head, fa_list) {
1085 struct fib_info *next_fi = fa->fa_info;
1086
1087 if (fa->fa_scope != res->scope ||
1088 fa->fa_type != RTN_UNICAST)
1089 continue;
1090
1091 if (next_fi->fib_priority > res->fi->fib_priority)
1092 break;
1093 if (!next_fi->fib_nh[0].nh_gw ||
1094 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1095 continue;
1096
1097 fib_alias_accessed(fa);
1098
1099 if (fi == NULL) {
1100 if (next_fi != res->fi)
1101 break;
1102 } else if (!fib_detect_death(fi, order, &last_resort,
1103 &last_idx, tb->tb_default)) {
1104 fib_result_assign(res, fi);
1105 tb->tb_default = order;
1106 goto out;
1107 }
1108 fi = next_fi;
1109 order++;
1110 }
1111
1112 if (order <= 0 || fi == NULL) {
1113 tb->tb_default = -1;
1114 goto out;
1115 }
1116
1117 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1118 tb->tb_default)) {
1119 fib_result_assign(res, fi);
1120 tb->tb_default = order;
1121 goto out;
1122 }
1123
1124 if (last_idx >= 0)
1125 fib_result_assign(res, last_resort);
1126 tb->tb_default = last_idx;
1127 out:
1128 return;
1129 }
1130
1131 void fib_update_nh_saddrs(struct net_device *dev)
1132 {
1133 struct hlist_head *head;
1134 struct hlist_node *node;
1135 struct fib_nh *nh;
1136 unsigned int hash;
1137
1138 hash = fib_devindex_hashfn(dev->ifindex);
1139 head = &fib_info_devhash[hash];
1140 hlist_for_each_entry(nh, node, head, nh_hash) {
1141 if (nh->nh_dev != dev)
1142 continue;
1143 nh->nh_saddr = inet_select_addr(nh->nh_dev,
1144 nh->nh_gw,
1145 nh->nh_cfg_scope);
1146 }
1147 }
1148
1149 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1150
1151 /*
1152 * Dead device goes up. We wake up dead nexthops.
1153 * It takes sense only on multipath routes.
1154 */
1155 int fib_sync_up(struct net_device *dev)
1156 {
1157 struct fib_info *prev_fi;
1158 unsigned int hash;
1159 struct hlist_head *head;
1160 struct hlist_node *node;
1161 struct fib_nh *nh;
1162 int ret;
1163
1164 if (!(dev->flags & IFF_UP))
1165 return 0;
1166
1167 prev_fi = NULL;
1168 hash = fib_devindex_hashfn(dev->ifindex);
1169 head = &fib_info_devhash[hash];
1170 ret = 0;
1171
1172 hlist_for_each_entry(nh, node, head, nh_hash) {
1173 struct fib_info *fi = nh->nh_parent;
1174 int alive;
1175
1176 BUG_ON(!fi->fib_nhs);
1177 if (nh->nh_dev != dev || fi == prev_fi)
1178 continue;
1179
1180 prev_fi = fi;
1181 alive = 0;
1182 change_nexthops(fi) {
1183 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1184 alive++;
1185 continue;
1186 }
1187 if (nexthop_nh->nh_dev == NULL ||
1188 !(nexthop_nh->nh_dev->flags & IFF_UP))
1189 continue;
1190 if (nexthop_nh->nh_dev != dev ||
1191 !__in_dev_get_rtnl(dev))
1192 continue;
1193 alive++;
1194 spin_lock_bh(&fib_multipath_lock);
1195 nexthop_nh->nh_power = 0;
1196 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1197 spin_unlock_bh(&fib_multipath_lock);
1198 } endfor_nexthops(fi)
1199
1200 if (alive > 0) {
1201 fi->fib_flags &= ~RTNH_F_DEAD;
1202 ret++;
1203 }
1204 }
1205
1206 return ret;
1207 }
1208
1209 /*
1210 * The algorithm is suboptimal, but it provides really
1211 * fair weighted route distribution.
1212 */
1213 void fib_select_multipath(struct fib_result *res)
1214 {
1215 struct fib_info *fi = res->fi;
1216 int w;
1217
1218 spin_lock_bh(&fib_multipath_lock);
1219 if (fi->fib_power <= 0) {
1220 int power = 0;
1221 change_nexthops(fi) {
1222 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1223 power += nexthop_nh->nh_weight;
1224 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1225 }
1226 } endfor_nexthops(fi);
1227 fi->fib_power = power;
1228 if (power <= 0) {
1229 spin_unlock_bh(&fib_multipath_lock);
1230 /* Race condition: route has just become dead. */
1231 res->nh_sel = 0;
1232 return;
1233 }
1234 }
1235
1236
1237 /* w should be random number [0..fi->fib_power-1],
1238 * it is pretty bad approximation.
1239 */
1240
1241 w = jiffies % fi->fib_power;
1242
1243 change_nexthops(fi) {
1244 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1245 nexthop_nh->nh_power) {
1246 w -= nexthop_nh->nh_power;
1247 if (w <= 0) {
1248 nexthop_nh->nh_power--;
1249 fi->fib_power--;
1250 res->nh_sel = nhsel;
1251 spin_unlock_bh(&fib_multipath_lock);
1252 return;
1253 }
1254 }
1255 } endfor_nexthops(fi);
1256
1257 /* Race condition: route has just become dead. */
1258 res->nh_sel = 0;
1259 spin_unlock_bh(&fib_multipath_lock);
1260 }
1261 #endif
Linux kernel - Deliverables
This page took 0.257803 seconds and 5 git commands to generate.