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FRV: Use generic show_interrupts()
[cris-mirror.git] / net / ipv4 / fib_semantics.c
blob641a5a2a9f9c4e7b9e1c2b11bebee5cb98ea43de
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 << 8) | fi->fib_scope;
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_scope == fi->fib_scope &&
252 nfi->fib_prefsrc == fi->fib_prefsrc &&
253 nfi->fib_priority == fi->fib_priority &&
254 memcmp(nfi->fib_metrics, fi->fib_metrics,
255 sizeof(u32) * RTAX_MAX) == 0 &&
256 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
257 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
258 return fi;
259 }
260
261 return NULL;
262 }
263
264 /* Check, that the gateway is already configured.
265 * Used only by redirect accept routine.
266 */
267 int ip_fib_check_default(__be32 gw, struct net_device *dev)
268 {
269 struct hlist_head *head;
270 struct hlist_node *node;
271 struct fib_nh *nh;
272 unsigned int hash;
273
274 spin_lock(&fib_info_lock);
275
276 hash = fib_devindex_hashfn(dev->ifindex);
277 head = &fib_info_devhash[hash];
278 hlist_for_each_entry(nh, node, head, nh_hash) {
279 if (nh->nh_dev == dev &&
280 nh->nh_gw == gw &&
281 !(nh->nh_flags & RTNH_F_DEAD)) {
282 spin_unlock(&fib_info_lock);
283 return 0;
284 }
285 }
286
287 spin_unlock(&fib_info_lock);
288
289 return -1;
290 }
291
292 static inline size_t fib_nlmsg_size(struct fib_info *fi)
293 {
294 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
295 + nla_total_size(4) /* RTA_TABLE */
296 + nla_total_size(4) /* RTA_DST */
297 + nla_total_size(4) /* RTA_PRIORITY */
298 + nla_total_size(4); /* RTA_PREFSRC */
299
300 /* space for nested metrics */
301 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
302
303 if (fi->fib_nhs) {
304 /* Also handles the special case fib_nhs == 1 */
305
306 /* each nexthop is packed in an attribute */
307 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
308
309 /* may contain flow and gateway attribute */
310 nhsize += 2 * nla_total_size(4);
311
312 /* all nexthops are packed in a nested attribute */
313 payload += nla_total_size(fi->fib_nhs * nhsize);
314 }
315
316 return payload;
317 }
318
319 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
320 int dst_len, u32 tb_id, struct nl_info *info,
321 unsigned int nlm_flags)
322 {
323 struct sk_buff *skb;
324 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
325 int err = -ENOBUFS;
326
327 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
328 if (skb == NULL)
329 goto errout;
330
331 err = fib_dump_info(skb, info->pid, seq, event, tb_id,
332 fa->fa_type, key, dst_len,
333 fa->fa_tos, fa->fa_info, nlm_flags);
334 if (err < 0) {
335 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
336 WARN_ON(err == -EMSGSIZE);
337 kfree_skb(skb);
338 goto errout;
339 }
340 rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
341 info->nlh, GFP_KERNEL);
342 return;
343 errout:
344 if (err < 0)
345 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
346 }
347
348 /* Return the first fib alias matching TOS with
349 * priority less than or equal to PRIO.
350 */
351 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
352 {
353 if (fah) {
354 struct fib_alias *fa;
355 list_for_each_entry(fa, fah, fa_list) {
356 if (fa->fa_tos > tos)
357 continue;
358 if (fa->fa_info->fib_priority >= prio ||
359 fa->fa_tos < tos)
360 return fa;
361 }
362 }
363 return NULL;
364 }
365
366 int fib_detect_death(struct fib_info *fi, int order,
367 struct fib_info **last_resort, int *last_idx, int dflt)
368 {
369 struct neighbour *n;
370 int state = NUD_NONE;
371
372 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
373 if (n) {
374 state = n->nud_state;
375 neigh_release(n);
376 }
377 if (state == NUD_REACHABLE)
378 return 0;
379 if ((state & NUD_VALID) && order != dflt)
380 return 0;
381 if ((state & NUD_VALID) ||
382 (*last_idx < 0 && order > dflt)) {
383 *last_resort = fi;
384 *last_idx = order;
385 }
386 return 1;
387 }
388
389 #ifdef CONFIG_IP_ROUTE_MULTIPATH
390
391 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
392 {
393 int nhs = 0;
394
395 while (rtnh_ok(rtnh, remaining)) {
396 nhs++;
397 rtnh = rtnh_next(rtnh, &remaining);
398 }
399
400 /* leftover implies invalid nexthop configuration, discard it */
401 return remaining > 0 ? 0 : nhs;
402 }
403
404 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
405 int remaining, struct fib_config *cfg)
406 {
407 change_nexthops(fi) {
408 int attrlen;
409
410 if (!rtnh_ok(rtnh, remaining))
411 return -EINVAL;
412
413 nexthop_nh->nh_flags =
414 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
415 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
416 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
417
418 attrlen = rtnh_attrlen(rtnh);
419 if (attrlen > 0) {
420 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
421
422 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
423 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
424 #ifdef CONFIG_IP_ROUTE_CLASSID
425 nla = nla_find(attrs, attrlen, RTA_FLOW);
426 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
427 #endif
428 }
429
430 rtnh = rtnh_next(rtnh, &remaining);
431 } endfor_nexthops(fi);
432
433 return 0;
434 }
435
436 #endif
437
438 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
439 {
440 #ifdef CONFIG_IP_ROUTE_MULTIPATH
441 struct rtnexthop *rtnh;
442 int remaining;
443 #endif
444
445 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
446 return 1;
447
448 if (cfg->fc_oif || cfg->fc_gw) {
449 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
450 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
451 return 0;
452 return 1;
453 }
454
455 #ifdef CONFIG_IP_ROUTE_MULTIPATH
456 if (cfg->fc_mp == NULL)
457 return 0;
458
459 rtnh = cfg->fc_mp;
460 remaining = cfg->fc_mp_len;
461
462 for_nexthops(fi) {
463 int attrlen;
464
465 if (!rtnh_ok(rtnh, remaining))
466 return -EINVAL;
467
468 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
469 return 1;
470
471 attrlen = rtnh_attrlen(rtnh);
472 if (attrlen < 0) {
473 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
474
475 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
476 if (nla && nla_get_be32(nla) != nh->nh_gw)
477 return 1;
478 #ifdef CONFIG_IP_ROUTE_CLASSID
479 nla = nla_find(attrs, attrlen, RTA_FLOW);
480 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
481 return 1;
482 #endif
483 }
484
485 rtnh = rtnh_next(rtnh, &remaining);
486 } endfor_nexthops(fi);
487 #endif
488 return 0;
489 }
490
491
492 /*
493 * Picture
494 * -------
495 *
496 * Semantics of nexthop is very messy by historical reasons.
497 * We have to take into account, that:
498 * a) gateway can be actually local interface address,
499 * so that gatewayed route is direct.
500 * b) gateway must be on-link address, possibly
501 * described not by an ifaddr, but also by a direct route.
502 * c) If both gateway and interface are specified, they should not
503 * contradict.
504 * d) If we use tunnel routes, gateway could be not on-link.
505 *
506 * Attempt to reconcile all of these (alas, self-contradictory) conditions
507 * results in pretty ugly and hairy code with obscure logic.
508 *
509 * I chose to generalized it instead, so that the size
510 * of code does not increase practically, but it becomes
511 * much more general.
512 * Every prefix is assigned a "scope" value: "host" is local address,
513 * "link" is direct route,
514 * [ ... "site" ... "interior" ... ]
515 * and "universe" is true gateway route with global meaning.
516 *
517 * Every prefix refers to a set of "nexthop"s (gw, oif),
518 * where gw must have narrower scope. This recursion stops
519 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
520 * which means that gw is forced to be on link.
521 *
522 * Code is still hairy, but now it is apparently logically
523 * consistent and very flexible. F.e. as by-product it allows
524 * to co-exists in peace independent exterior and interior
525 * routing processes.
526 *
527 * Normally it looks as following.
528 *
529 * {universe prefix} -> (gw, oif) [scope link]
530 * |
531 * |-> {link prefix} -> (gw, oif) [scope local]
532 * |
533 * |-> {local prefix} (terminal node)
534 */
535 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
536 struct fib_nh *nh)
537 {
538 int err;
539 struct net *net;
540 struct net_device *dev;
541
542 net = cfg->fc_nlinfo.nl_net;
543 if (nh->nh_gw) {
544 struct fib_result res;
545
546 if (nh->nh_flags & RTNH_F_ONLINK) {
547
548 if (cfg->fc_scope >= RT_SCOPE_LINK)
549 return -EINVAL;
550 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
551 return -EINVAL;
552 dev = __dev_get_by_index(net, nh->nh_oif);
553 if (!dev)
554 return -ENODEV;
555 if (!(dev->flags & IFF_UP))
556 return -ENETDOWN;
557 nh->nh_dev = dev;
558 dev_hold(dev);
559 nh->nh_scope = RT_SCOPE_LINK;
560 return 0;
561 }
562 rcu_read_lock();
563 {
564 struct flowi4 fl4 = {
565 .daddr = nh->nh_gw,
566 .flowi4_scope = cfg->fc_scope + 1,
567 .flowi4_oif = nh->nh_oif,
568 };
569
570 /* It is not necessary, but requires a bit of thinking */
571 if (fl4.flowi4_scope < RT_SCOPE_LINK)
572 fl4.flowi4_scope = RT_SCOPE_LINK;
573 err = fib_lookup(net, &fl4, &res);
574 if (err) {
575 rcu_read_unlock();
576 return err;
577 }
578 }
579 err = -EINVAL;
580 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
581 goto out;
582 nh->nh_scope = res.scope;
583 nh->nh_oif = FIB_RES_OIF(res);
584 nh->nh_dev = dev = FIB_RES_DEV(res);
585 if (!dev)
586 goto out;
587 dev_hold(dev);
588 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
589 } else {
590 struct in_device *in_dev;
591
592 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
593 return -EINVAL;
594
595 rcu_read_lock();
596 err = -ENODEV;
597 in_dev = inetdev_by_index(net, nh->nh_oif);
598 if (in_dev == NULL)
599 goto out;
600 err = -ENETDOWN;
601 if (!(in_dev->dev->flags & IFF_UP))
602 goto out;
603 nh->nh_dev = in_dev->dev;
604 dev_hold(nh->nh_dev);
605 nh->nh_scope = RT_SCOPE_HOST;
606 err = 0;
607 }
608 out:
609 rcu_read_unlock();
610 return err;
611 }
612
613 static inline unsigned int fib_laddr_hashfn(__be32 val)
614 {
615 unsigned int mask = (fib_info_hash_size - 1);
616
617 return ((__force u32)val ^
618 ((__force u32)val >> 7) ^
619 ((__force u32)val >> 14)) & mask;
620 }
621
622 static struct hlist_head *fib_info_hash_alloc(int bytes)
623 {
624 if (bytes <= PAGE_SIZE)
625 return kzalloc(bytes, GFP_KERNEL);
626 else
627 return (struct hlist_head *)
628 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
629 get_order(bytes));
630 }
631
632 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
633 {
634 if (!hash)
635 return;
636
637 if (bytes <= PAGE_SIZE)
638 kfree(hash);
639 else
640 free_pages((unsigned long) hash, get_order(bytes));
641 }
642
643 static void fib_info_hash_move(struct hlist_head *new_info_hash,
644 struct hlist_head *new_laddrhash,
645 unsigned int new_size)
646 {
647 struct hlist_head *old_info_hash, *old_laddrhash;
648 unsigned int old_size = fib_info_hash_size;
649 unsigned int i, bytes;
650
651 spin_lock_bh(&fib_info_lock);
652 old_info_hash = fib_info_hash;
653 old_laddrhash = fib_info_laddrhash;
654 fib_info_hash_size = new_size;
655
656 for (i = 0; i < old_size; i++) {
657 struct hlist_head *head = &fib_info_hash[i];
658 struct hlist_node *node, *n;
659 struct fib_info *fi;
660
661 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
662 struct hlist_head *dest;
663 unsigned int new_hash;
664
665 hlist_del(&fi->fib_hash);
666
667 new_hash = fib_info_hashfn(fi);
668 dest = &new_info_hash[new_hash];
669 hlist_add_head(&fi->fib_hash, dest);
670 }
671 }
672 fib_info_hash = new_info_hash;
673
674 for (i = 0; i < old_size; i++) {
675 struct hlist_head *lhead = &fib_info_laddrhash[i];
676 struct hlist_node *node, *n;
677 struct fib_info *fi;
678
679 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
680 struct hlist_head *ldest;
681 unsigned int new_hash;
682
683 hlist_del(&fi->fib_lhash);
684
685 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
686 ldest = &new_laddrhash[new_hash];
687 hlist_add_head(&fi->fib_lhash, ldest);
688 }
689 }
690 fib_info_laddrhash = new_laddrhash;
691
692 spin_unlock_bh(&fib_info_lock);
693
694 bytes = old_size * sizeof(struct hlist_head *);
695 fib_info_hash_free(old_info_hash, bytes);
696 fib_info_hash_free(old_laddrhash, bytes);
697 }
698
699 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
700 {
701 nh->nh_saddr = inet_select_addr(nh->nh_dev,
702 nh->nh_gw,
703 nh->nh_parent->fib_scope);
704 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
705
706 return nh->nh_saddr;
707 }
708
709 struct fib_info *fib_create_info(struct fib_config *cfg)
710 {
711 int err;
712 struct fib_info *fi = NULL;
713 struct fib_info *ofi;
714 int nhs = 1;
715 struct net *net = cfg->fc_nlinfo.nl_net;
716
717 if (cfg->fc_type > RTN_MAX)
718 goto err_inval;
719
720 /* Fast check to catch the most weird cases */
721 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
722 goto err_inval;
723
724 #ifdef CONFIG_IP_ROUTE_MULTIPATH
725 if (cfg->fc_mp) {
726 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
727 if (nhs == 0)
728 goto err_inval;
729 }
730 #endif
731
732 err = -ENOBUFS;
733 if (fib_info_cnt >= fib_info_hash_size) {
734 unsigned int new_size = fib_info_hash_size << 1;
735 struct hlist_head *new_info_hash;
736 struct hlist_head *new_laddrhash;
737 unsigned int bytes;
738
739 if (!new_size)
740 new_size = 1;
741 bytes = new_size * sizeof(struct hlist_head *);
742 new_info_hash = fib_info_hash_alloc(bytes);
743 new_laddrhash = fib_info_hash_alloc(bytes);
744 if (!new_info_hash || !new_laddrhash) {
745 fib_info_hash_free(new_info_hash, bytes);
746 fib_info_hash_free(new_laddrhash, bytes);
747 } else
748 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
749
750 if (!fib_info_hash_size)
751 goto failure;
752 }
753
754 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
755 if (fi == NULL)
756 goto failure;
757 if (cfg->fc_mx) {
758 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
759 if (!fi->fib_metrics)
760 goto failure;
761 } else
762 fi->fib_metrics = (u32 *) dst_default_metrics;
763 fib_info_cnt++;
764
765 fi->fib_net = hold_net(net);
766 fi->fib_protocol = cfg->fc_protocol;
767 fi->fib_scope = cfg->fc_scope;
768 fi->fib_flags = cfg->fc_flags;
769 fi->fib_priority = cfg->fc_priority;
770 fi->fib_prefsrc = cfg->fc_prefsrc;
771
772 fi->fib_nhs = nhs;
773 change_nexthops(fi) {
774 nexthop_nh->nh_parent = fi;
775 } endfor_nexthops(fi)
776
777 if (cfg->fc_mx) {
778 struct nlattr *nla;
779 int remaining;
780
781 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
782 int type = nla_type(nla);
783
784 if (type) {
785 if (type > RTAX_MAX)
786 goto err_inval;
787 fi->fib_metrics[type - 1] = nla_get_u32(nla);
788 }
789 }
790 }
791
792 if (cfg->fc_mp) {
793 #ifdef CONFIG_IP_ROUTE_MULTIPATH
794 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
795 if (err != 0)
796 goto failure;
797 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
798 goto err_inval;
799 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
800 goto err_inval;
801 #ifdef CONFIG_IP_ROUTE_CLASSID
802 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
803 goto err_inval;
804 #endif
805 #else
806 goto err_inval;
807 #endif
808 } else {
809 struct fib_nh *nh = fi->fib_nh;
810
811 nh->nh_oif = cfg->fc_oif;
812 nh->nh_gw = cfg->fc_gw;
813 nh->nh_flags = cfg->fc_flags;
814 #ifdef CONFIG_IP_ROUTE_CLASSID
815 nh->nh_tclassid = cfg->fc_flow;
816 #endif
817 #ifdef CONFIG_IP_ROUTE_MULTIPATH
818 nh->nh_weight = 1;
819 #endif
820 }
821
822 if (fib_props[cfg->fc_type].error) {
823 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
824 goto err_inval;
825 goto link_it;
826 } else {
827 switch (cfg->fc_type) {
828 case RTN_UNICAST:
829 case RTN_LOCAL:
830 case RTN_BROADCAST:
831 case RTN_ANYCAST:
832 case RTN_MULTICAST:
833 break;
834 default:
835 goto err_inval;
836 }
837 }
838
839 if (cfg->fc_scope > RT_SCOPE_HOST)
840 goto err_inval;
841
842 if (cfg->fc_scope == RT_SCOPE_HOST) {
843 struct fib_nh *nh = fi->fib_nh;
844
845 /* Local address is added. */
846 if (nhs != 1 || nh->nh_gw)
847 goto err_inval;
848 nh->nh_scope = RT_SCOPE_NOWHERE;
849 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
850 err = -ENODEV;
851 if (nh->nh_dev == NULL)
852 goto failure;
853 } else {
854 change_nexthops(fi) {
855 err = fib_check_nh(cfg, fi, nexthop_nh);
856 if (err != 0)
857 goto failure;
858 } endfor_nexthops(fi)
859 }
860
861 if (fi->fib_prefsrc) {
862 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
863 fi->fib_prefsrc != cfg->fc_dst)
864 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
865 goto err_inval;
866 }
867
868 change_nexthops(fi) {
869 fib_info_update_nh_saddr(net, nexthop_nh);
870 } endfor_nexthops(fi)
871
872 link_it:
873 ofi = fib_find_info(fi);
874 if (ofi) {
875 fi->fib_dead = 1;
876 free_fib_info(fi);
877 ofi->fib_treeref++;
878 return ofi;
879 }
880
881 fi->fib_treeref++;
882 atomic_inc(&fi->fib_clntref);
883 spin_lock_bh(&fib_info_lock);
884 hlist_add_head(&fi->fib_hash,
885 &fib_info_hash[fib_info_hashfn(fi)]);
886 if (fi->fib_prefsrc) {
887 struct hlist_head *head;
888
889 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
890 hlist_add_head(&fi->fib_lhash, head);
891 }
892 change_nexthops(fi) {
893 struct hlist_head *head;
894 unsigned int hash;
895
896 if (!nexthop_nh->nh_dev)
897 continue;
898 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
899 head = &fib_info_devhash[hash];
900 hlist_add_head(&nexthop_nh->nh_hash, head);
901 } endfor_nexthops(fi)
902 spin_unlock_bh(&fib_info_lock);
903 return fi;
904
905 err_inval:
906 err = -EINVAL;
907
908 failure:
909 if (fi) {
910 fi->fib_dead = 1;
911 free_fib_info(fi);
912 }
913
914 return ERR_PTR(err);
915 }
916
917 int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
918 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
919 struct fib_info *fi, unsigned int flags)
920 {
921 struct nlmsghdr *nlh;
922 struct rtmsg *rtm;
923
924 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
925 if (nlh == NULL)
926 return -EMSGSIZE;
927
928 rtm = nlmsg_data(nlh);
929 rtm->rtm_family = AF_INET;
930 rtm->rtm_dst_len = dst_len;
931 rtm->rtm_src_len = 0;
932 rtm->rtm_tos = tos;
933 if (tb_id < 256)
934 rtm->rtm_table = tb_id;
935 else
936 rtm->rtm_table = RT_TABLE_COMPAT;
937 NLA_PUT_U32(skb, RTA_TABLE, tb_id);
938 rtm->rtm_type = type;
939 rtm->rtm_flags = fi->fib_flags;
940 rtm->rtm_scope = fi->fib_scope;
941 rtm->rtm_protocol = fi->fib_protocol;
942
943 if (rtm->rtm_dst_len)
944 NLA_PUT_BE32(skb, RTA_DST, dst);
945
946 if (fi->fib_priority)
947 NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
948
949 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
950 goto nla_put_failure;
951
952 if (fi->fib_prefsrc)
953 NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc);
954
955 if (fi->fib_nhs == 1) {
956 if (fi->fib_nh->nh_gw)
957 NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
958
959 if (fi->fib_nh->nh_oif)
960 NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
961 #ifdef CONFIG_IP_ROUTE_CLASSID
962 if (fi->fib_nh[0].nh_tclassid)
963 NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
964 #endif
965 }
966 #ifdef CONFIG_IP_ROUTE_MULTIPATH
967 if (fi->fib_nhs > 1) {
968 struct rtnexthop *rtnh;
969 struct nlattr *mp;
970
971 mp = nla_nest_start(skb, RTA_MULTIPATH);
972 if (mp == NULL)
973 goto nla_put_failure;
974
975 for_nexthops(fi) {
976 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
977 if (rtnh == NULL)
978 goto nla_put_failure;
979
980 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
981 rtnh->rtnh_hops = nh->nh_weight - 1;
982 rtnh->rtnh_ifindex = nh->nh_oif;
983
984 if (nh->nh_gw)
985 NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw);
986 #ifdef CONFIG_IP_ROUTE_CLASSID
987 if (nh->nh_tclassid)
988 NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
989 #endif
990 /* length of rtnetlink header + attributes */
991 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
992 } endfor_nexthops(fi);
993
994 nla_nest_end(skb, mp);
995 }
996 #endif
997 return nlmsg_end(skb, nlh);
998
999 nla_put_failure:
1000 nlmsg_cancel(skb, nlh);
1001 return -EMSGSIZE;
1002 }
1003
1004 /*
1005 * Update FIB if:
1006 * - local address disappeared -> we must delete all the entries
1007 * referring to it.
1008 * - device went down -> we must shutdown all nexthops going via it.
1009 */
1010 int fib_sync_down_addr(struct net *net, __be32 local)
1011 {
1012 int ret = 0;
1013 unsigned int hash = fib_laddr_hashfn(local);
1014 struct hlist_head *head = &fib_info_laddrhash[hash];
1015 struct hlist_node *node;
1016 struct fib_info *fi;
1017
1018 if (fib_info_laddrhash == NULL || local == 0)
1019 return 0;
1020
1021 hlist_for_each_entry(fi, node, head, fib_lhash) {
1022 if (!net_eq(fi->fib_net, net))
1023 continue;
1024 if (fi->fib_prefsrc == local) {
1025 fi->fib_flags |= RTNH_F_DEAD;
1026 ret++;
1027 }
1028 }
1029 return ret;
1030 }
1031
1032 int fib_sync_down_dev(struct net_device *dev, int force)
1033 {
1034 int ret = 0;
1035 int scope = RT_SCOPE_NOWHERE;
1036 struct fib_info *prev_fi = NULL;
1037 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1038 struct hlist_head *head = &fib_info_devhash[hash];
1039 struct hlist_node *node;
1040 struct fib_nh *nh;
1041
1042 if (force)
1043 scope = -1;
1044
1045 hlist_for_each_entry(nh, node, head, nh_hash) {
1046 struct fib_info *fi = nh->nh_parent;
1047 int dead;
1048
1049 BUG_ON(!fi->fib_nhs);
1050 if (nh->nh_dev != dev || fi == prev_fi)
1051 continue;
1052 prev_fi = fi;
1053 dead = 0;
1054 change_nexthops(fi) {
1055 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1056 dead++;
1057 else if (nexthop_nh->nh_dev == dev &&
1058 nexthop_nh->nh_scope != scope) {
1059 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1060 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1061 spin_lock_bh(&fib_multipath_lock);
1062 fi->fib_power -= nexthop_nh->nh_power;
1063 nexthop_nh->nh_power = 0;
1064 spin_unlock_bh(&fib_multipath_lock);
1065 #endif
1066 dead++;
1067 }
1068 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1069 if (force > 1 && nexthop_nh->nh_dev == dev) {
1070 dead = fi->fib_nhs;
1071 break;
1072 }
1073 #endif
1074 } endfor_nexthops(fi)
1075 if (dead == fi->fib_nhs) {
1076 fi->fib_flags |= RTNH_F_DEAD;
1077 ret++;
1078 }
1079 }
1080
1081 return ret;
1082 }
1083
1084 /* Must be invoked inside of an RCU protected region. */
1085 void fib_select_default(struct fib_result *res)
1086 {
1087 struct fib_info *fi = NULL, *last_resort = NULL;
1088 struct list_head *fa_head = res->fa_head;
1089 struct fib_table *tb = res->table;
1090 int order = -1, last_idx = -1;
1091 struct fib_alias *fa;
1092
1093 list_for_each_entry_rcu(fa, fa_head, fa_list) {
1094 struct fib_info *next_fi = fa->fa_info;
1095
1096 if (next_fi->fib_scope != res->scope ||
1097 fa->fa_type != RTN_UNICAST)
1098 continue;
1099
1100 if (next_fi->fib_priority > res->fi->fib_priority)
1101 break;
1102 if (!next_fi->fib_nh[0].nh_gw ||
1103 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1104 continue;
1105
1106 fib_alias_accessed(fa);
1107
1108 if (fi == NULL) {
1109 if (next_fi != res->fi)
1110 break;
1111 } else if (!fib_detect_death(fi, order, &last_resort,
1112 &last_idx, tb->tb_default)) {
1113 fib_result_assign(res, fi);
1114 tb->tb_default = order;
1115 goto out;
1116 }
1117 fi = next_fi;
1118 order++;
1119 }
1120
1121 if (order <= 0 || fi == NULL) {
1122 tb->tb_default = -1;
1123 goto out;
1124 }
1125
1126 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1127 tb->tb_default)) {
1128 fib_result_assign(res, fi);
1129 tb->tb_default = order;
1130 goto out;
1131 }
1132
1133 if (last_idx >= 0)
1134 fib_result_assign(res, last_resort);
1135 tb->tb_default = last_idx;
1136 out:
1137 return;
1138 }
1139
1140 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1141
1142 /*
1143 * Dead device goes up. We wake up dead nexthops.
1144 * It takes sense only on multipath routes.
1145 */
1146 int fib_sync_up(struct net_device *dev)
1147 {
1148 struct fib_info *prev_fi;
1149 unsigned int hash;
1150 struct hlist_head *head;
1151 struct hlist_node *node;
1152 struct fib_nh *nh;
1153 int ret;
1154
1155 if (!(dev->flags & IFF_UP))
1156 return 0;
1157
1158 prev_fi = NULL;
1159 hash = fib_devindex_hashfn(dev->ifindex);
1160 head = &fib_info_devhash[hash];
1161 ret = 0;
1162
1163 hlist_for_each_entry(nh, node, head, nh_hash) {
1164 struct fib_info *fi = nh->nh_parent;
1165 int alive;
1166
1167 BUG_ON(!fi->fib_nhs);
1168 if (nh->nh_dev != dev || fi == prev_fi)
1169 continue;
1170
1171 prev_fi = fi;
1172 alive = 0;
1173 change_nexthops(fi) {
1174 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1175 alive++;
1176 continue;
1177 }
1178 if (nexthop_nh->nh_dev == NULL ||
1179 !(nexthop_nh->nh_dev->flags & IFF_UP))
1180 continue;
1181 if (nexthop_nh->nh_dev != dev ||
1182 !__in_dev_get_rtnl(dev))
1183 continue;
1184 alive++;
1185 spin_lock_bh(&fib_multipath_lock);
1186 nexthop_nh->nh_power = 0;
1187 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1188 spin_unlock_bh(&fib_multipath_lock);
1189 } endfor_nexthops(fi)
1190
1191 if (alive > 0) {
1192 fi->fib_flags &= ~RTNH_F_DEAD;
1193 ret++;
1194 }
1195 }
1196
1197 return ret;
1198 }
1199
1200 /*
1201 * The algorithm is suboptimal, but it provides really
1202 * fair weighted route distribution.
1203 */
1204 void fib_select_multipath(struct fib_result *res)
1205 {
1206 struct fib_info *fi = res->fi;
1207 int w;
1208
1209 spin_lock_bh(&fib_multipath_lock);
1210 if (fi->fib_power <= 0) {
1211 int power = 0;
1212 change_nexthops(fi) {
1213 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1214 power += nexthop_nh->nh_weight;
1215 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1216 }
1217 } endfor_nexthops(fi);
1218 fi->fib_power = power;
1219 if (power <= 0) {
1220 spin_unlock_bh(&fib_multipath_lock);
1221 /* Race condition: route has just become dead. */
1222 res->nh_sel = 0;
1223 return;
1224 }
1225 }
1226
1227
1228 /* w should be random number [0..fi->fib_power-1],
1229 * it is pretty bad approximation.
1230 */
1231
1232 w = jiffies % fi->fib_power;
1233
1234 change_nexthops(fi) {
1235 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1236 nexthop_nh->nh_power) {
1237 w -= nexthop_nh->nh_power;
1238 if (w <= 0) {
1239 nexthop_nh->nh_power--;
1240 fi->fib_power--;
1241 res->nh_sel = nhsel;
1242 spin_unlock_bh(&fib_multipath_lock);
1243 return;
1244 }
1245 }
1246 } endfor_nexthops(fi);
1247
1248 /* Race condition: route has just become dead. */
1249 res->nh_sel = 0;
1250 spin_unlock_bh(&fib_multipath_lock);
1251 }
1252 #endif
CRIS linux kernel tree