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1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * IPv4 Forwarding Information Base: semantics.
7 *
8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16#include <asm/uaccess.h>
17#include <linux/bitops.h>
18#include <linux/types.h>
19#include <linux/kernel.h>
20#include <linux/jiffies.h>
21#include <linux/mm.h>
22#include <linux/string.h>
23#include <linux/socket.h>
24#include <linux/sockios.h>
25#include <linux/errno.h>
26#include <linux/in.h>
27#include <linux/inet.h>
28#include <linux/inetdevice.h>
29#include <linux/netdevice.h>
30#include <linux/if_arp.h>
31#include <linux/proc_fs.h>
32#include <linux/skbuff.h>
33#include <linux/init.h>
34#include <linux/slab.h>
35
36#include <net/arp.h>
37#include <net/ip.h>
38#include <net/protocol.h>
39#include <net/route.h>
40#include <net/tcp.h>
41#include <net/sock.h>
42#include <net/ip_fib.h>
43#include <net/netlink.h>
44#include <net/nexthop.h>
45
46#include "fib_lookup.h"
47
48static DEFINE_SPINLOCK(fib_info_lock);
49static struct hlist_head *fib_info_hash;
50static struct hlist_head *fib_info_laddrhash;
51static unsigned int fib_info_hash_size;
52static unsigned int fib_info_cnt;
53
54#define DEVINDEX_HASHBITS 8
55#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
56static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
57
58#ifdef CONFIG_IP_ROUTE_MULTIPATH
59
60static DEFINE_SPINLOCK(fib_multipath_lock);
61
62#define for_nexthops(fi) { \
63 int nhsel; const struct fib_nh *nh; \
64 for (nhsel = 0, nh = (fi)->fib_nh; \
65 nhsel < (fi)->fib_nhs; \
66 nh++, nhsel++)
67
68#define change_nexthops(fi) { \
69 int nhsel; struct fib_nh *nexthop_nh; \
70 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
71 nhsel < (fi)->fib_nhs; \
72 nexthop_nh++, nhsel++)
73
74#else /* CONFIG_IP_ROUTE_MULTIPATH */
75
76/* Hope, that gcc will optimize it to get rid of dummy loop */
77
78#define for_nexthops(fi) { \
79 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
80 for (nhsel = 0; nhsel < 1; nhsel++)
81
82#define change_nexthops(fi) { \
83 int nhsel; \
84 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87#endif /* CONFIG_IP_ROUTE_MULTIPATH */
88
89#define endfor_nexthops(fi) }
90
91
92const struct fib_prop fib_props[RTN_MAX + 1] = {
93 [RTN_UNSPEC] = {
94 .error = 0,
95 .scope = RT_SCOPE_NOWHERE,
96 },
97 [RTN_UNICAST] = {
98 .error = 0,
99 .scope = RT_SCOPE_UNIVERSE,
100 },
101 [RTN_LOCAL] = {
102 .error = 0,
103 .scope = RT_SCOPE_HOST,
104 },
105 [RTN_BROADCAST] = {
106 .error = 0,
107 .scope = RT_SCOPE_LINK,
108 },
109 [RTN_ANYCAST] = {
110 .error = 0,
111 .scope = RT_SCOPE_LINK,
112 },
113 [RTN_MULTICAST] = {
114 .error = 0,
115 .scope = RT_SCOPE_UNIVERSE,
116 },
117 [RTN_BLACKHOLE] = {
118 .error = -EINVAL,
119 .scope = RT_SCOPE_UNIVERSE,
120 },
121 [RTN_UNREACHABLE] = {
122 .error = -EHOSTUNREACH,
123 .scope = RT_SCOPE_UNIVERSE,
124 },
125 [RTN_PROHIBIT] = {
126 .error = -EACCES,
127 .scope = RT_SCOPE_UNIVERSE,
128 },
129 [RTN_THROW] = {
130 .error = -EAGAIN,
131 .scope = RT_SCOPE_UNIVERSE,
132 },
133 [RTN_NAT] = {
134 .error = -EINVAL,
135 .scope = RT_SCOPE_NOWHERE,
136 },
137 [RTN_XRESOLVE] = {
138 .error = -EINVAL,
139 .scope = RT_SCOPE_NOWHERE,
140 },
141};
142
143/* Release a nexthop info record */
144static void free_fib_info_rcu(struct rcu_head *head)
145{
146 struct fib_info *fi = container_of(head, struct fib_info, rcu);
147
148 change_nexthops(fi) {
149 if (nexthop_nh->nh_dev)
150 dev_put(nexthop_nh->nh_dev);
151 } endfor_nexthops(fi);
152
153 release_net(fi->fib_net);
154 if (fi->fib_metrics != (u32 *) dst_default_metrics)
155 kfree(fi->fib_metrics);
156 kfree(fi);
157}
158
159void free_fib_info(struct fib_info *fi)
160{
161 if (fi->fib_dead == 0) {
162 pr_warn("Freeing alive fib_info %p\n", fi);
163 return;
164 }
165 fib_info_cnt--;
166 call_rcu(&fi->rcu, free_fib_info_rcu);
167}
168
169void fib_release_info(struct fib_info *fi)
170{
171 spin_lock_bh(&fib_info_lock);
172 if (fi && --fi->fib_treeref == 0) {
173 hlist_del(&fi->fib_hash);
174 if (fi->fib_prefsrc)
175 hlist_del(&fi->fib_lhash);
176 change_nexthops(fi) {
177 if (!nexthop_nh->nh_dev)
178 continue;
179 hlist_del(&nexthop_nh->nh_hash);
180 } endfor_nexthops(fi)
181 fi->fib_dead = 1;
182 fib_info_put(fi);
183 }
184 spin_unlock_bh(&fib_info_lock);
185}
186
187static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
188{
189 const struct fib_nh *onh = ofi->fib_nh;
190
191 for_nexthops(fi) {
192 if (nh->nh_oif != onh->nh_oif ||
193 nh->nh_gw != onh->nh_gw ||
194 nh->nh_scope != onh->nh_scope ||
195#ifdef CONFIG_IP_ROUTE_MULTIPATH
196 nh->nh_weight != onh->nh_weight ||
197#endif
198#ifdef CONFIG_IP_ROUTE_CLASSID
199 nh->nh_tclassid != onh->nh_tclassid ||
200#endif
201 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
202 return -1;
203 onh++;
204 } endfor_nexthops(fi);
205 return 0;
206}
207
208static inline unsigned int fib_devindex_hashfn(unsigned int val)
209{
210 unsigned int mask = DEVINDEX_HASHSIZE - 1;
211
212 return (val ^
213 (val >> DEVINDEX_HASHBITS) ^
214 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
215}
216
217static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
218{
219 unsigned int mask = (fib_info_hash_size - 1);
220 unsigned int val = fi->fib_nhs;
221
222 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
223 val ^= (__force u32)fi->fib_prefsrc;
224 val ^= fi->fib_priority;
225 for_nexthops(fi) {
226 val ^= fib_devindex_hashfn(nh->nh_oif);
227 } endfor_nexthops(fi)
228
229 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
230}
231
232static struct fib_info *fib_find_info(const struct fib_info *nfi)
233{
234 struct hlist_head *head;
235 struct hlist_node *node;
236 struct fib_info *fi;
237 unsigned int hash;
238
239 hash = fib_info_hashfn(nfi);
240 head = &fib_info_hash[hash];
241
242 hlist_for_each_entry(fi, node, head, fib_hash) {
243 if (!net_eq(fi->fib_net, nfi->fib_net))
244 continue;
245 if (fi->fib_nhs != nfi->fib_nhs)
246 continue;
247 if (nfi->fib_protocol == fi->fib_protocol &&
248 nfi->fib_scope == fi->fib_scope &&
249 nfi->fib_prefsrc == fi->fib_prefsrc &&
250 nfi->fib_priority == fi->fib_priority &&
251 memcmp(nfi->fib_metrics, fi->fib_metrics,
252 sizeof(u32) * RTAX_MAX) == 0 &&
253 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
254 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
255 return fi;
256 }
257
258 return NULL;
259}
260
261/* Check, that the gateway is already configured.
262 * Used only by redirect accept routine.
263 */
264int ip_fib_check_default(__be32 gw, struct net_device *dev)
265{
266 struct hlist_head *head;
267 struct hlist_node *node;
268 struct fib_nh *nh;
269 unsigned int hash;
270
271 spin_lock(&fib_info_lock);
272
273 hash = fib_devindex_hashfn(dev->ifindex);
274 head = &fib_info_devhash[hash];
275 hlist_for_each_entry(nh, node, head, nh_hash) {
276 if (nh->nh_dev == dev &&
277 nh->nh_gw == gw &&
278 !(nh->nh_flags & RTNH_F_DEAD)) {
279 spin_unlock(&fib_info_lock);
280 return 0;
281 }
282 }
283
284 spin_unlock(&fib_info_lock);
285
286 return -1;
287}
288
289static inline size_t fib_nlmsg_size(struct fib_info *fi)
290{
291 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
292 + nla_total_size(4) /* RTA_TABLE */
293 + nla_total_size(4) /* RTA_DST */
294 + nla_total_size(4) /* RTA_PRIORITY */
295 + nla_total_size(4); /* RTA_PREFSRC */
296
297 /* space for nested metrics */
298 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
299
300 if (fi->fib_nhs) {
301 /* Also handles the special case fib_nhs == 1 */
302
303 /* each nexthop is packed in an attribute */
304 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
305
306 /* may contain flow and gateway attribute */
307 nhsize += 2 * nla_total_size(4);
308
309 /* all nexthops are packed in a nested attribute */
310 payload += nla_total_size(fi->fib_nhs * nhsize);
311 }
312
313 return payload;
314}
315
316void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
317 int dst_len, u32 tb_id, struct nl_info *info,
318 unsigned int nlm_flags)
319{
320 struct sk_buff *skb;
321 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
322 int err = -ENOBUFS;
323
324 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
325 if (skb == NULL)
326 goto errout;
327
328 err = fib_dump_info(skb, info->pid, seq, event, tb_id,
329 fa->fa_type, key, dst_len,
330 fa->fa_tos, fa->fa_info, nlm_flags);
331 if (err < 0) {
332 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
333 WARN_ON(err == -EMSGSIZE);
334 kfree_skb(skb);
335 goto errout;
336 }
337 rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
338 info->nlh, GFP_KERNEL);
339 return;
340errout:
341 if (err < 0)
342 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
343}
344
345/* Return the first fib alias matching TOS with
346 * priority less than or equal to PRIO.
347 */
348struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
349{
350 if (fah) {
351 struct fib_alias *fa;
352 list_for_each_entry(fa, fah, fa_list) {
353 if (fa->fa_tos > tos)
354 continue;
355 if (fa->fa_info->fib_priority >= prio ||
356 fa->fa_tos < tos)
357 return fa;
358 }
359 }
360 return NULL;
361}
362
363int fib_detect_death(struct fib_info *fi, int order,
364 struct fib_info **last_resort, int *last_idx, int dflt)
365{
366 struct neighbour *n;
367 int state = NUD_NONE;
368
369 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
370 if (n) {
371 state = n->nud_state;
372 neigh_release(n);
373 }
374 if (state == NUD_REACHABLE)
375 return 0;
376 if ((state & NUD_VALID) && order != dflt)
377 return 0;
378 if ((state & NUD_VALID) ||
379 (*last_idx < 0 && order > dflt)) {
380 *last_resort = fi;
381 *last_idx = order;
382 }
383 return 1;
384}
385
386#ifdef CONFIG_IP_ROUTE_MULTIPATH
387
388static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
389{
390 int nhs = 0;
391
392 while (rtnh_ok(rtnh, remaining)) {
393 nhs++;
394 rtnh = rtnh_next(rtnh, &remaining);
395 }
396
397 /* leftover implies invalid nexthop configuration, discard it */
398 return remaining > 0 ? 0 : nhs;
399}
400
401static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
402 int remaining, struct fib_config *cfg)
403{
404 change_nexthops(fi) {
405 int attrlen;
406
407 if (!rtnh_ok(rtnh, remaining))
408 return -EINVAL;
409
410 nexthop_nh->nh_flags =
411 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
412 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
413 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
414
415 attrlen = rtnh_attrlen(rtnh);
416 if (attrlen > 0) {
417 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
418
419 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
420 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
421#ifdef CONFIG_IP_ROUTE_CLASSID
422 nla = nla_find(attrs, attrlen, RTA_FLOW);
423 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
424#endif
425 }
426
427 rtnh = rtnh_next(rtnh, &remaining);
428 } endfor_nexthops(fi);
429
430 return 0;
431}
432
433#endif
434
435int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
436{
437#ifdef CONFIG_IP_ROUTE_MULTIPATH
438 struct rtnexthop *rtnh;
439 int remaining;
440#endif
441
442 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
443 return 1;
444
445 if (cfg->fc_oif || cfg->fc_gw) {
446 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
447 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
448 return 0;
449 return 1;
450 }
451
452#ifdef CONFIG_IP_ROUTE_MULTIPATH
453 if (cfg->fc_mp == NULL)
454 return 0;
455
456 rtnh = cfg->fc_mp;
457 remaining = cfg->fc_mp_len;
458
459 for_nexthops(fi) {
460 int attrlen;
461
462 if (!rtnh_ok(rtnh, remaining))
463 return -EINVAL;
464
465 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
466 return 1;
467
468 attrlen = rtnh_attrlen(rtnh);
469 if (attrlen < 0) {
470 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
471
472 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
473 if (nla && nla_get_be32(nla) != nh->nh_gw)
474 return 1;
475#ifdef CONFIG_IP_ROUTE_CLASSID
476 nla = nla_find(attrs, attrlen, RTA_FLOW);
477 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
478 return 1;
479#endif
480 }
481
482 rtnh = rtnh_next(rtnh, &remaining);
483 } endfor_nexthops(fi);
484#endif
485 return 0;
486}
487
488
489/*
490 * Picture
491 * -------
492 *
493 * Semantics of nexthop is very messy by historical reasons.
494 * We have to take into account, that:
495 * a) gateway can be actually local interface address,
496 * so that gatewayed route is direct.
497 * b) gateway must be on-link address, possibly
498 * described not by an ifaddr, but also by a direct route.
499 * c) If both gateway and interface are specified, they should not
500 * contradict.
501 * d) If we use tunnel routes, gateway could be not on-link.
502 *
503 * Attempt to reconcile all of these (alas, self-contradictory) conditions
504 * results in pretty ugly and hairy code with obscure logic.
505 *
506 * I chose to generalized it instead, so that the size
507 * of code does not increase practically, but it becomes
508 * much more general.
509 * Every prefix is assigned a "scope" value: "host" is local address,
510 * "link" is direct route,
511 * [ ... "site" ... "interior" ... ]
512 * and "universe" is true gateway route with global meaning.
513 *
514 * Every prefix refers to a set of "nexthop"s (gw, oif),
515 * where gw must have narrower scope. This recursion stops
516 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
517 * which means that gw is forced to be on link.
518 *
519 * Code is still hairy, but now it is apparently logically
520 * consistent and very flexible. F.e. as by-product it allows
521 * to co-exists in peace independent exterior and interior
522 * routing processes.
523 *
524 * Normally it looks as following.
525 *
526 * {universe prefix} -> (gw, oif) [scope link]
527 * |
528 * |-> {link prefix} -> (gw, oif) [scope local]
529 * |
530 * |-> {local prefix} (terminal node)
531 */
532static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
533 struct fib_nh *nh)
534{
535 int err;
536 struct net *net;
537 struct net_device *dev;
538
539 net = cfg->fc_nlinfo.nl_net;
540 if (nh->nh_gw) {
541 struct fib_result res;
542
543 if (nh->nh_flags & RTNH_F_ONLINK) {
544
545 if (cfg->fc_scope >= RT_SCOPE_LINK)
546 return -EINVAL;
547 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
548 return -EINVAL;
549 dev = __dev_get_by_index(net, nh->nh_oif);
550 if (!dev)
551 return -ENODEV;
552 if (!(dev->flags & IFF_UP))
553 return -ENETDOWN;
554 nh->nh_dev = dev;
555 dev_hold(dev);
556 nh->nh_scope = RT_SCOPE_LINK;
557 return 0;
558 }
559 rcu_read_lock();
560 {
561 struct flowi4 fl4 = {
562 .daddr = nh->nh_gw,
563 .flowi4_scope = cfg->fc_scope + 1,
564 .flowi4_oif = nh->nh_oif,
565 };
566
567 /* It is not necessary, but requires a bit of thinking */
568 if (fl4.flowi4_scope < RT_SCOPE_LINK)
569 fl4.flowi4_scope = RT_SCOPE_LINK;
570 err = fib_lookup(net, &fl4, &res);
571 if (err) {
572 rcu_read_unlock();
573 return err;
574 }
575 }
576 err = -EINVAL;
577 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
578 goto out;
579 nh->nh_scope = res.scope;
580 nh->nh_oif = FIB_RES_OIF(res);
581 nh->nh_dev = dev = FIB_RES_DEV(res);
582 if (!dev)
583 goto out;
584 dev_hold(dev);
585 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
586 } else {
587 struct in_device *in_dev;
588
589 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
590 return -EINVAL;
591
592 rcu_read_lock();
593 err = -ENODEV;
594 in_dev = inetdev_by_index(net, nh->nh_oif);
595 if (in_dev == NULL)
596 goto out;
597 err = -ENETDOWN;
598 if (!(in_dev->dev->flags & IFF_UP))
599 goto out;
600 nh->nh_dev = in_dev->dev;
601 dev_hold(nh->nh_dev);
602 nh->nh_scope = RT_SCOPE_HOST;
603 err = 0;
604 }
605out:
606 rcu_read_unlock();
607 return err;
608}
609
610static inline unsigned int fib_laddr_hashfn(__be32 val)
611{
612 unsigned int mask = (fib_info_hash_size - 1);
613
614 return ((__force u32)val ^
615 ((__force u32)val >> 7) ^
616 ((__force u32)val >> 14)) & mask;
617}
618
619static struct hlist_head *fib_info_hash_alloc(int bytes)
620{
621 if (bytes <= PAGE_SIZE)
622 return kzalloc(bytes, GFP_KERNEL);
623 else
624 return (struct hlist_head *)
625 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
626 get_order(bytes));
627}
628
629static void fib_info_hash_free(struct hlist_head *hash, int bytes)
630{
631 if (!hash)
632 return;
633
634 if (bytes <= PAGE_SIZE)
635 kfree(hash);
636 else
637 free_pages((unsigned long) hash, get_order(bytes));
638}
639
640static void fib_info_hash_move(struct hlist_head *new_info_hash,
641 struct hlist_head *new_laddrhash,
642 unsigned int new_size)
643{
644 struct hlist_head *old_info_hash, *old_laddrhash;
645 unsigned int old_size = fib_info_hash_size;
646 unsigned int i, bytes;
647
648 spin_lock_bh(&fib_info_lock);
649 old_info_hash = fib_info_hash;
650 old_laddrhash = fib_info_laddrhash;
651 fib_info_hash_size = new_size;
652
653 for (i = 0; i < old_size; i++) {
654 struct hlist_head *head = &fib_info_hash[i];
655 struct hlist_node *node, *n;
656 struct fib_info *fi;
657
658 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
659 struct hlist_head *dest;
660 unsigned int new_hash;
661
662 hlist_del(&fi->fib_hash);
663
664 new_hash = fib_info_hashfn(fi);
665 dest = &new_info_hash[new_hash];
666 hlist_add_head(&fi->fib_hash, dest);
667 }
668 }
669 fib_info_hash = new_info_hash;
670
671 for (i = 0; i < old_size; i++) {
672 struct hlist_head *lhead = &fib_info_laddrhash[i];
673 struct hlist_node *node, *n;
674 struct fib_info *fi;
675
676 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
677 struct hlist_head *ldest;
678 unsigned int new_hash;
679
680 hlist_del(&fi->fib_lhash);
681
682 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
683 ldest = &new_laddrhash[new_hash];
684 hlist_add_head(&fi->fib_lhash, ldest);
685 }
686 }
687 fib_info_laddrhash = new_laddrhash;
688
689 spin_unlock_bh(&fib_info_lock);
690
691 bytes = old_size * sizeof(struct hlist_head *);
692 fib_info_hash_free(old_info_hash, bytes);
693 fib_info_hash_free(old_laddrhash, bytes);
694}
695
696__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
697{
698 nh->nh_saddr = inet_select_addr(nh->nh_dev,
699 nh->nh_gw,
700 nh->nh_parent->fib_scope);
701 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
702
703 return nh->nh_saddr;
704}
705
706struct fib_info *fib_create_info(struct fib_config *cfg)
707{
708 int err;
709 struct fib_info *fi = NULL;
710 struct fib_info *ofi;
711 int nhs = 1;
712 struct net *net = cfg->fc_nlinfo.nl_net;
713
714 if (cfg->fc_type > RTN_MAX)
715 goto err_inval;
716
717 /* Fast check to catch the most weird cases */
718 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
719 goto err_inval;
720
721#ifdef CONFIG_IP_ROUTE_MULTIPATH
722 if (cfg->fc_mp) {
723 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
724 if (nhs == 0)
725 goto err_inval;
726 }
727#endif
728
729 err = -ENOBUFS;
730 if (fib_info_cnt >= fib_info_hash_size) {
731 unsigned int new_size = fib_info_hash_size << 1;
732 struct hlist_head *new_info_hash;
733 struct hlist_head *new_laddrhash;
734 unsigned int bytes;
735
736 if (!new_size)
737 new_size = 1;
738 bytes = new_size * sizeof(struct hlist_head *);
739 new_info_hash = fib_info_hash_alloc(bytes);
740 new_laddrhash = fib_info_hash_alloc(bytes);
741 if (!new_info_hash || !new_laddrhash) {
742 fib_info_hash_free(new_info_hash, bytes);
743 fib_info_hash_free(new_laddrhash, bytes);
744 } else
745 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
746
747 if (!fib_info_hash_size)
748 goto failure;
749 }
750
751 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
752 if (fi == NULL)
753 goto failure;
754 if (cfg->fc_mx) {
755 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
756 if (!fi->fib_metrics)
757 goto failure;
758 } else
759 fi->fib_metrics = (u32 *) dst_default_metrics;
760 fib_info_cnt++;
761
762 fi->fib_net = hold_net(net);
763 fi->fib_protocol = cfg->fc_protocol;
764 fi->fib_scope = cfg->fc_scope;
765 fi->fib_flags = cfg->fc_flags;
766 fi->fib_priority = cfg->fc_priority;
767 fi->fib_prefsrc = cfg->fc_prefsrc;
768
769 fi->fib_nhs = nhs;
770 change_nexthops(fi) {
771 nexthop_nh->nh_parent = fi;
772 } endfor_nexthops(fi)
773
774 if (cfg->fc_mx) {
775 struct nlattr *nla;
776 int remaining;
777
778 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
779 int type = nla_type(nla);
780
781 if (type) {
782 if (type > RTAX_MAX)
783 goto err_inval;
784 fi->fib_metrics[type - 1] = nla_get_u32(nla);
785 }
786 }
787 }
788
789 if (cfg->fc_mp) {
790#ifdef CONFIG_IP_ROUTE_MULTIPATH
791 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
792 if (err != 0)
793 goto failure;
794 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
795 goto err_inval;
796 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
797 goto err_inval;
798#ifdef CONFIG_IP_ROUTE_CLASSID
799 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
800 goto err_inval;
801#endif
802#else
803 goto err_inval;
804#endif
805 } else {
806 struct fib_nh *nh = fi->fib_nh;
807
808 nh->nh_oif = cfg->fc_oif;
809 nh->nh_gw = cfg->fc_gw;
810 nh->nh_flags = cfg->fc_flags;
811#ifdef CONFIG_IP_ROUTE_CLASSID
812 nh->nh_tclassid = cfg->fc_flow;
813#endif
814#ifdef CONFIG_IP_ROUTE_MULTIPATH
815 nh->nh_weight = 1;
816#endif
817 }
818
819 if (fib_props[cfg->fc_type].error) {
820 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
821 goto err_inval;
822 goto link_it;
823 } else {
824 switch (cfg->fc_type) {
825 case RTN_UNICAST:
826 case RTN_LOCAL:
827 case RTN_BROADCAST:
828 case RTN_ANYCAST:
829 case RTN_MULTICAST:
830 break;
831 default:
832 goto err_inval;
833 }
834 }
835
836 if (cfg->fc_scope > RT_SCOPE_HOST)
837 goto err_inval;
838
839 if (cfg->fc_scope == RT_SCOPE_HOST) {
840 struct fib_nh *nh = fi->fib_nh;
841
842 /* Local address is added. */
843 if (nhs != 1 || nh->nh_gw)
844 goto err_inval;
845 nh->nh_scope = RT_SCOPE_NOWHERE;
846 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
847 err = -ENODEV;
848 if (nh->nh_dev == NULL)
849 goto failure;
850 } else {
851 change_nexthops(fi) {
852 err = fib_check_nh(cfg, fi, nexthop_nh);
853 if (err != 0)
854 goto failure;
855 } endfor_nexthops(fi)
856 }
857
858 if (fi->fib_prefsrc) {
859 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
860 fi->fib_prefsrc != cfg->fc_dst)
861 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
862 goto err_inval;
863 }
864
865 change_nexthops(fi) {
866 fib_info_update_nh_saddr(net, nexthop_nh);
867 } endfor_nexthops(fi)
868
869link_it:
870 ofi = fib_find_info(fi);
871 if (ofi) {
872 fi->fib_dead = 1;
873 free_fib_info(fi);
874 ofi->fib_treeref++;
875 return ofi;
876 }
877
878 fi->fib_treeref++;
879 atomic_inc(&fi->fib_clntref);
880 spin_lock_bh(&fib_info_lock);
881 hlist_add_head(&fi->fib_hash,
882 &fib_info_hash[fib_info_hashfn(fi)]);
883 if (fi->fib_prefsrc) {
884 struct hlist_head *head;
885
886 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
887 hlist_add_head(&fi->fib_lhash, head);
888 }
889 change_nexthops(fi) {
890 struct hlist_head *head;
891 unsigned int hash;
892
893 if (!nexthop_nh->nh_dev)
894 continue;
895 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
896 head = &fib_info_devhash[hash];
897 hlist_add_head(&nexthop_nh->nh_hash, head);
898 } endfor_nexthops(fi)
899 spin_unlock_bh(&fib_info_lock);
900 return fi;
901
902err_inval:
903 err = -EINVAL;
904
905failure:
906 if (fi) {
907 fi->fib_dead = 1;
908 free_fib_info(fi);
909 }
910
911 return ERR_PTR(err);
912}
913
914int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
915 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
916 struct fib_info *fi, unsigned int flags)
917{
918 struct nlmsghdr *nlh;
919 struct rtmsg *rtm;
920
921 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
922 if (nlh == NULL)
923 return -EMSGSIZE;
924
925 rtm = nlmsg_data(nlh);
926 rtm->rtm_family = AF_INET;
927 rtm->rtm_dst_len = dst_len;
928 rtm->rtm_src_len = 0;
929 rtm->rtm_tos = tos;
930 if (tb_id < 256)
931 rtm->rtm_table = tb_id;
932 else
933 rtm->rtm_table = RT_TABLE_COMPAT;
934 if (nla_put_u32(skb, RTA_TABLE, tb_id))
935 goto nla_put_failure;
936 rtm->rtm_type = type;
937 rtm->rtm_flags = fi->fib_flags;
938 rtm->rtm_scope = fi->fib_scope;
939 rtm->rtm_protocol = fi->fib_protocol;
940
941 if (rtm->rtm_dst_len &&
942 nla_put_be32(skb, RTA_DST, dst))
943 goto nla_put_failure;
944 if (fi->fib_priority &&
945 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
946 goto nla_put_failure;
947 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
948 goto nla_put_failure;
949
950 if (fi->fib_prefsrc &&
951 nla_put_be32(skb, RTA_PREFSRC, fi->fib_prefsrc))
952 goto nla_put_failure;
953 if (fi->fib_nhs == 1) {
954 if (fi->fib_nh->nh_gw &&
955 nla_put_be32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
956 goto nla_put_failure;
957 if (fi->fib_nh->nh_oif &&
958 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
959 goto nla_put_failure;
960#ifdef CONFIG_IP_ROUTE_CLASSID
961 if (fi->fib_nh[0].nh_tclassid &&
962 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
963 goto nla_put_failure;
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 goto nla_put_failure;
987#ifdef CONFIG_IP_ROUTE_CLASSID
988 if (nh->nh_tclassid &&
989 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
990 goto nla_put_failure;
991#endif
992 /* length of rtnetlink header + attributes */
993 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
994 } endfor_nexthops(fi);
995
996 nla_nest_end(skb, mp);
997 }
998#endif
999 return nlmsg_end(skb, nlh);
1000
1001nla_put_failure:
1002 nlmsg_cancel(skb, nlh);
1003 return -EMSGSIZE;
1004}
1005
1006/*
1007 * Update FIB if:
1008 * - local address disappeared -> we must delete all the entries
1009 * referring to it.
1010 * - device went down -> we must shutdown all nexthops going via it.
1011 */
1012int fib_sync_down_addr(struct net *net, __be32 local)
1013{
1014 int ret = 0;
1015 unsigned int hash = fib_laddr_hashfn(local);
1016 struct hlist_head *head = &fib_info_laddrhash[hash];
1017 struct hlist_node *node;
1018 struct fib_info *fi;
1019
1020 if (fib_info_laddrhash == NULL || local == 0)
1021 return 0;
1022
1023 hlist_for_each_entry(fi, node, head, fib_lhash) {
1024 if (!net_eq(fi->fib_net, net))
1025 continue;
1026 if (fi->fib_prefsrc == local) {
1027 fi->fib_flags |= RTNH_F_DEAD;
1028 ret++;
1029 }
1030 }
1031 return ret;
1032}
1033
1034int fib_sync_down_dev(struct net_device *dev, int force)
1035{
1036 int ret = 0;
1037 int scope = RT_SCOPE_NOWHERE;
1038 struct fib_info *prev_fi = NULL;
1039 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1040 struct hlist_head *head = &fib_info_devhash[hash];
1041 struct hlist_node *node;
1042 struct fib_nh *nh;
1043
1044 if (force)
1045 scope = -1;
1046
1047 hlist_for_each_entry(nh, node, head, nh_hash) {
1048 struct fib_info *fi = nh->nh_parent;
1049 int dead;
1050
1051 BUG_ON(!fi->fib_nhs);
1052 if (nh->nh_dev != dev || fi == prev_fi)
1053 continue;
1054 prev_fi = fi;
1055 dead = 0;
1056 change_nexthops(fi) {
1057 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1058 dead++;
1059 else if (nexthop_nh->nh_dev == dev &&
1060 nexthop_nh->nh_scope != scope) {
1061 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1062#ifdef CONFIG_IP_ROUTE_MULTIPATH
1063 spin_lock_bh(&fib_multipath_lock);
1064 fi->fib_power -= nexthop_nh->nh_power;
1065 nexthop_nh->nh_power = 0;
1066 spin_unlock_bh(&fib_multipath_lock);
1067#endif
1068 dead++;
1069 }
1070#ifdef CONFIG_IP_ROUTE_MULTIPATH
1071 if (force > 1 && nexthop_nh->nh_dev == dev) {
1072 dead = fi->fib_nhs;
1073 break;
1074 }
1075#endif
1076 } endfor_nexthops(fi)
1077 if (dead == fi->fib_nhs) {
1078 fi->fib_flags |= RTNH_F_DEAD;
1079 ret++;
1080 }
1081 }
1082
1083 return ret;
1084}
1085
1086/* Must be invoked inside of an RCU protected region. */
1087void fib_select_default(struct fib_result *res)
1088{
1089 struct fib_info *fi = NULL, *last_resort = NULL;
1090 struct list_head *fa_head = res->fa_head;
1091 struct fib_table *tb = res->table;
1092 int order = -1, last_idx = -1;
1093 struct fib_alias *fa;
1094
1095 list_for_each_entry_rcu(fa, fa_head, fa_list) {
1096 struct fib_info *next_fi = fa->fa_info;
1097
1098 if (next_fi->fib_scope != res->scope ||
1099 fa->fa_type != RTN_UNICAST)
1100 continue;
1101
1102 if (next_fi->fib_priority > res->fi->fib_priority)
1103 break;
1104 if (!next_fi->fib_nh[0].nh_gw ||
1105 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1106 continue;
1107
1108 fib_alias_accessed(fa);
1109
1110 if (fi == NULL) {
1111 if (next_fi != res->fi)
1112 break;
1113 } else if (!fib_detect_death(fi, order, &last_resort,
1114 &last_idx, tb->tb_default)) {
1115 fib_result_assign(res, fi);
1116 tb->tb_default = order;
1117 goto out;
1118 }
1119 fi = next_fi;
1120 order++;
1121 }
1122
1123 if (order <= 0 || fi == NULL) {
1124 tb->tb_default = -1;
1125 goto out;
1126 }
1127
1128 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1129 tb->tb_default)) {
1130 fib_result_assign(res, fi);
1131 tb->tb_default = order;
1132 goto out;
1133 }
1134
1135 if (last_idx >= 0)
1136 fib_result_assign(res, last_resort);
1137 tb->tb_default = last_idx;
1138out:
1139 return;
1140}
1141
1142#ifdef CONFIG_IP_ROUTE_MULTIPATH
1143
1144/*
1145 * Dead device goes up. We wake up dead nexthops.
1146 * It takes sense only on multipath routes.
1147 */
1148int fib_sync_up(struct net_device *dev)
1149{
1150 struct fib_info *prev_fi;
1151 unsigned int hash;
1152 struct hlist_head *head;
1153 struct hlist_node *node;
1154 struct fib_nh *nh;
1155 int ret;
1156
1157 if (!(dev->flags & IFF_UP))
1158 return 0;
1159
1160 prev_fi = NULL;
1161 hash = fib_devindex_hashfn(dev->ifindex);
1162 head = &fib_info_devhash[hash];
1163 ret = 0;
1164
1165 hlist_for_each_entry(nh, node, head, nh_hash) {
1166 struct fib_info *fi = nh->nh_parent;
1167 int alive;
1168
1169 BUG_ON(!fi->fib_nhs);
1170 if (nh->nh_dev != dev || fi == prev_fi)
1171 continue;
1172
1173 prev_fi = fi;
1174 alive = 0;
1175 change_nexthops(fi) {
1176 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1177 alive++;
1178 continue;
1179 }
1180 if (nexthop_nh->nh_dev == NULL ||
1181 !(nexthop_nh->nh_dev->flags & IFF_UP))
1182 continue;
1183 if (nexthop_nh->nh_dev != dev ||
1184 !__in_dev_get_rtnl(dev))
1185 continue;
1186 alive++;
1187 spin_lock_bh(&fib_multipath_lock);
1188 nexthop_nh->nh_power = 0;
1189 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1190 spin_unlock_bh(&fib_multipath_lock);
1191 } endfor_nexthops(fi)
1192
1193 if (alive > 0) {
1194 fi->fib_flags &= ~RTNH_F_DEAD;
1195 ret++;
1196 }
1197 }
1198
1199 return ret;
1200}
1201
1202/*
1203 * The algorithm is suboptimal, but it provides really
1204 * fair weighted route distribution.
1205 */
1206void fib_select_multipath(struct fib_result *res)
1207{
1208 struct fib_info *fi = res->fi;
1209 int w;
1210
1211 spin_lock_bh(&fib_multipath_lock);
1212 if (fi->fib_power <= 0) {
1213 int power = 0;
1214 change_nexthops(fi) {
1215 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1216 power += nexthop_nh->nh_weight;
1217 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1218 }
1219 } endfor_nexthops(fi);
1220 fi->fib_power = power;
1221 if (power <= 0) {
1222 spin_unlock_bh(&fib_multipath_lock);
1223 /* Race condition: route has just become dead. */
1224 res->nh_sel = 0;
1225 return;
1226 }
1227 }
1228
1229
1230 /* w should be random number [0..fi->fib_power-1],
1231 * it is pretty bad approximation.
1232 */
1233
1234 w = jiffies % fi->fib_power;
1235
1236 change_nexthops(fi) {
1237 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1238 nexthop_nh->nh_power) {
1239 w -= nexthop_nh->nh_power;
1240 if (w <= 0) {
1241 nexthop_nh->nh_power--;
1242 fi->fib_power--;
1243 res->nh_sel = nhsel;
1244 spin_unlock_bh(&fib_multipath_lock);
1245 return;
1246 }
1247 }
1248 } endfor_nexthops(fi);
1249
1250 /* Race condition: route has just become dead. */
1251 res->nh_sel = 0;
1252 spin_unlock_bh(&fib_multipath_lock);
1253}
1254#endif
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 <linux/uaccess.h>
17#include <linux/bitops.h>
18#include <linux/types.h>
19#include <linux/kernel.h>
20#include <linux/jiffies.h>
21#include <linux/mm.h>
22#include <linux/string.h>
23#include <linux/socket.h>
24#include <linux/sockios.h>
25#include <linux/errno.h>
26#include <linux/in.h>
27#include <linux/inet.h>
28#include <linux/inetdevice.h>
29#include <linux/netdevice.h>
30#include <linux/if_arp.h>
31#include <linux/proc_fs.h>
32#include <linux/skbuff.h>
33#include <linux/init.h>
34#include <linux/slab.h>
35
36#include <net/arp.h>
37#include <net/ip.h>
38#include <net/protocol.h>
39#include <net/route.h>
40#include <net/tcp.h>
41#include <net/sock.h>
42#include <net/ip_fib.h>
43#include <net/netlink.h>
44#include <net/nexthop.h>
45#include <net/lwtunnel.h>
46
47#include "fib_lookup.h"
48
49static DEFINE_SPINLOCK(fib_info_lock);
50static struct hlist_head *fib_info_hash;
51static struct hlist_head *fib_info_laddrhash;
52static unsigned int fib_info_hash_size;
53static unsigned int fib_info_cnt;
54
55#define DEVINDEX_HASHBITS 8
56#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59#ifdef CONFIG_IP_ROUTE_MULTIPATH
60u32 fib_multipath_secret __read_mostly;
61
62#define for_nexthops(fi) { \
63 int nhsel; const struct fib_nh *nh; \
64 for (nhsel = 0, nh = (fi)->fib_nh; \
65 nhsel < (fi)->fib_nhs; \
66 nh++, nhsel++)
67
68#define change_nexthops(fi) { \
69 int nhsel; struct fib_nh *nexthop_nh; \
70 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
71 nhsel < (fi)->fib_nhs; \
72 nexthop_nh++, nhsel++)
73
74#else /* CONFIG_IP_ROUTE_MULTIPATH */
75
76/* Hope, that gcc will optimize it to get rid of dummy loop */
77
78#define for_nexthops(fi) { \
79 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
80 for (nhsel = 0; nhsel < 1; nhsel++)
81
82#define change_nexthops(fi) { \
83 int nhsel; \
84 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87#endif /* CONFIG_IP_ROUTE_MULTIPATH */
88
89#define endfor_nexthops(fi) }
90
91
92const struct fib_prop fib_props[RTN_MAX + 1] = {
93 [RTN_UNSPEC] = {
94 .error = 0,
95 .scope = RT_SCOPE_NOWHERE,
96 },
97 [RTN_UNICAST] = {
98 .error = 0,
99 .scope = RT_SCOPE_UNIVERSE,
100 },
101 [RTN_LOCAL] = {
102 .error = 0,
103 .scope = RT_SCOPE_HOST,
104 },
105 [RTN_BROADCAST] = {
106 .error = 0,
107 .scope = RT_SCOPE_LINK,
108 },
109 [RTN_ANYCAST] = {
110 .error = 0,
111 .scope = RT_SCOPE_LINK,
112 },
113 [RTN_MULTICAST] = {
114 .error = 0,
115 .scope = RT_SCOPE_UNIVERSE,
116 },
117 [RTN_BLACKHOLE] = {
118 .error = -EINVAL,
119 .scope = RT_SCOPE_UNIVERSE,
120 },
121 [RTN_UNREACHABLE] = {
122 .error = -EHOSTUNREACH,
123 .scope = RT_SCOPE_UNIVERSE,
124 },
125 [RTN_PROHIBIT] = {
126 .error = -EACCES,
127 .scope = RT_SCOPE_UNIVERSE,
128 },
129 [RTN_THROW] = {
130 .error = -EAGAIN,
131 .scope = RT_SCOPE_UNIVERSE,
132 },
133 [RTN_NAT] = {
134 .error = -EINVAL,
135 .scope = RT_SCOPE_NOWHERE,
136 },
137 [RTN_XRESOLVE] = {
138 .error = -EINVAL,
139 .scope = RT_SCOPE_NOWHERE,
140 },
141};
142
143static void rt_fibinfo_free(struct rtable __rcu **rtp)
144{
145 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
146
147 if (!rt)
148 return;
149
150 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
151 * because we waited an RCU grace period before calling
152 * free_fib_info_rcu()
153 */
154
155 dst_free(&rt->dst);
156}
157
158static void free_nh_exceptions(struct fib_nh *nh)
159{
160 struct fnhe_hash_bucket *hash;
161 int i;
162
163 hash = rcu_dereference_protected(nh->nh_exceptions, 1);
164 if (!hash)
165 return;
166 for (i = 0; i < FNHE_HASH_SIZE; i++) {
167 struct fib_nh_exception *fnhe;
168
169 fnhe = rcu_dereference_protected(hash[i].chain, 1);
170 while (fnhe) {
171 struct fib_nh_exception *next;
172
173 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
174
175 rt_fibinfo_free(&fnhe->fnhe_rth_input);
176 rt_fibinfo_free(&fnhe->fnhe_rth_output);
177
178 kfree(fnhe);
179
180 fnhe = next;
181 }
182 }
183 kfree(hash);
184}
185
186static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
187{
188 int cpu;
189
190 if (!rtp)
191 return;
192
193 for_each_possible_cpu(cpu) {
194 struct rtable *rt;
195
196 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
197 if (rt)
198 dst_free(&rt->dst);
199 }
200 free_percpu(rtp);
201}
202
203/* Release a nexthop info record */
204static void free_fib_info_rcu(struct rcu_head *head)
205{
206 struct fib_info *fi = container_of(head, struct fib_info, rcu);
207
208 change_nexthops(fi) {
209 if (nexthop_nh->nh_dev)
210 dev_put(nexthop_nh->nh_dev);
211 lwtstate_put(nexthop_nh->nh_lwtstate);
212 free_nh_exceptions(nexthop_nh);
213 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
214 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
215 } endfor_nexthops(fi);
216
217 if (fi->fib_metrics != (u32 *) dst_default_metrics)
218 kfree(fi->fib_metrics);
219 kfree(fi);
220}
221
222void free_fib_info(struct fib_info *fi)
223{
224 if (fi->fib_dead == 0) {
225 pr_warn("Freeing alive fib_info %p\n", fi);
226 return;
227 }
228 fib_info_cnt--;
229#ifdef CONFIG_IP_ROUTE_CLASSID
230 change_nexthops(fi) {
231 if (nexthop_nh->nh_tclassid)
232 fi->fib_net->ipv4.fib_num_tclassid_users--;
233 } endfor_nexthops(fi);
234#endif
235 call_rcu(&fi->rcu, free_fib_info_rcu);
236}
237EXPORT_SYMBOL_GPL(free_fib_info);
238
239void fib_release_info(struct fib_info *fi)
240{
241 spin_lock_bh(&fib_info_lock);
242 if (fi && --fi->fib_treeref == 0) {
243 hlist_del(&fi->fib_hash);
244 if (fi->fib_prefsrc)
245 hlist_del(&fi->fib_lhash);
246 change_nexthops(fi) {
247 if (!nexthop_nh->nh_dev)
248 continue;
249 hlist_del(&nexthop_nh->nh_hash);
250 } endfor_nexthops(fi)
251 fi->fib_dead = 1;
252 fib_info_put(fi);
253 }
254 spin_unlock_bh(&fib_info_lock);
255}
256
257static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
258{
259 const struct fib_nh *onh = ofi->fib_nh;
260
261 for_nexthops(fi) {
262 if (nh->nh_oif != onh->nh_oif ||
263 nh->nh_gw != onh->nh_gw ||
264 nh->nh_scope != onh->nh_scope ||
265#ifdef CONFIG_IP_ROUTE_MULTIPATH
266 nh->nh_weight != onh->nh_weight ||
267#endif
268#ifdef CONFIG_IP_ROUTE_CLASSID
269 nh->nh_tclassid != onh->nh_tclassid ||
270#endif
271 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
272 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
273 return -1;
274 onh++;
275 } endfor_nexthops(fi);
276 return 0;
277}
278
279static inline unsigned int fib_devindex_hashfn(unsigned int val)
280{
281 unsigned int mask = DEVINDEX_HASHSIZE - 1;
282
283 return (val ^
284 (val >> DEVINDEX_HASHBITS) ^
285 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
286}
287
288static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
289{
290 unsigned int mask = (fib_info_hash_size - 1);
291 unsigned int val = fi->fib_nhs;
292
293 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
294 val ^= (__force u32)fi->fib_prefsrc;
295 val ^= fi->fib_priority;
296 for_nexthops(fi) {
297 val ^= fib_devindex_hashfn(nh->nh_oif);
298 } endfor_nexthops(fi)
299
300 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
301}
302
303static struct fib_info *fib_find_info(const struct fib_info *nfi)
304{
305 struct hlist_head *head;
306 struct fib_info *fi;
307 unsigned int hash;
308
309 hash = fib_info_hashfn(nfi);
310 head = &fib_info_hash[hash];
311
312 hlist_for_each_entry(fi, head, fib_hash) {
313 if (!net_eq(fi->fib_net, nfi->fib_net))
314 continue;
315 if (fi->fib_nhs != nfi->fib_nhs)
316 continue;
317 if (nfi->fib_protocol == fi->fib_protocol &&
318 nfi->fib_scope == fi->fib_scope &&
319 nfi->fib_prefsrc == fi->fib_prefsrc &&
320 nfi->fib_priority == fi->fib_priority &&
321 nfi->fib_type == fi->fib_type &&
322 memcmp(nfi->fib_metrics, fi->fib_metrics,
323 sizeof(u32) * RTAX_MAX) == 0 &&
324 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
325 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
326 return fi;
327 }
328
329 return NULL;
330}
331
332/* Check, that the gateway is already configured.
333 * Used only by redirect accept routine.
334 */
335int ip_fib_check_default(__be32 gw, struct net_device *dev)
336{
337 struct hlist_head *head;
338 struct fib_nh *nh;
339 unsigned int hash;
340
341 spin_lock(&fib_info_lock);
342
343 hash = fib_devindex_hashfn(dev->ifindex);
344 head = &fib_info_devhash[hash];
345 hlist_for_each_entry(nh, head, nh_hash) {
346 if (nh->nh_dev == dev &&
347 nh->nh_gw == gw &&
348 !(nh->nh_flags & RTNH_F_DEAD)) {
349 spin_unlock(&fib_info_lock);
350 return 0;
351 }
352 }
353
354 spin_unlock(&fib_info_lock);
355
356 return -1;
357}
358
359static inline size_t fib_nlmsg_size(struct fib_info *fi)
360{
361 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
362 + nla_total_size(4) /* RTA_TABLE */
363 + nla_total_size(4) /* RTA_DST */
364 + nla_total_size(4) /* RTA_PRIORITY */
365 + nla_total_size(4) /* RTA_PREFSRC */
366 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
367
368 /* space for nested metrics */
369 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
370
371 if (fi->fib_nhs) {
372 size_t nh_encapsize = 0;
373 /* Also handles the special case fib_nhs == 1 */
374
375 /* each nexthop is packed in an attribute */
376 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
377
378 /* may contain flow and gateway attribute */
379 nhsize += 2 * nla_total_size(4);
380
381 /* grab encap info */
382 for_nexthops(fi) {
383 if (nh->nh_lwtstate) {
384 /* RTA_ENCAP_TYPE */
385 nh_encapsize += lwtunnel_get_encap_size(
386 nh->nh_lwtstate);
387 /* RTA_ENCAP */
388 nh_encapsize += nla_total_size(2);
389 }
390 } endfor_nexthops(fi);
391
392 /* all nexthops are packed in a nested attribute */
393 payload += nla_total_size((fi->fib_nhs * nhsize) +
394 nh_encapsize);
395
396 }
397
398 return payload;
399}
400
401void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
402 int dst_len, u32 tb_id, const struct nl_info *info,
403 unsigned int nlm_flags)
404{
405 struct sk_buff *skb;
406 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
407 int err = -ENOBUFS;
408
409 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
410 if (!skb)
411 goto errout;
412
413 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
414 fa->fa_type, key, dst_len,
415 fa->fa_tos, fa->fa_info, nlm_flags);
416 if (err < 0) {
417 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
418 WARN_ON(err == -EMSGSIZE);
419 kfree_skb(skb);
420 goto errout;
421 }
422 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
423 info->nlh, GFP_KERNEL);
424 return;
425errout:
426 if (err < 0)
427 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
428}
429
430static int fib_detect_death(struct fib_info *fi, int order,
431 struct fib_info **last_resort, int *last_idx,
432 int dflt)
433{
434 struct neighbour *n;
435 int state = NUD_NONE;
436
437 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
438 if (n) {
439 state = n->nud_state;
440 neigh_release(n);
441 } else {
442 return 0;
443 }
444 if (state == NUD_REACHABLE)
445 return 0;
446 if ((state & NUD_VALID) && order != dflt)
447 return 0;
448 if ((state & NUD_VALID) ||
449 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
450 *last_resort = fi;
451 *last_idx = order;
452 }
453 return 1;
454}
455
456#ifdef CONFIG_IP_ROUTE_MULTIPATH
457
458static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
459{
460 int nhs = 0;
461
462 while (rtnh_ok(rtnh, remaining)) {
463 nhs++;
464 rtnh = rtnh_next(rtnh, &remaining);
465 }
466
467 /* leftover implies invalid nexthop configuration, discard it */
468 return remaining > 0 ? 0 : nhs;
469}
470
471static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
472 int remaining, struct fib_config *cfg)
473{
474 struct net *net = cfg->fc_nlinfo.nl_net;
475 int ret;
476
477 change_nexthops(fi) {
478 int attrlen;
479
480 if (!rtnh_ok(rtnh, remaining))
481 return -EINVAL;
482
483 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
484 return -EINVAL;
485
486 nexthop_nh->nh_flags =
487 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
488 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
489 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
490
491 attrlen = rtnh_attrlen(rtnh);
492 if (attrlen > 0) {
493 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
494
495 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
496 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
497#ifdef CONFIG_IP_ROUTE_CLASSID
498 nla = nla_find(attrs, attrlen, RTA_FLOW);
499 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
500 if (nexthop_nh->nh_tclassid)
501 fi->fib_net->ipv4.fib_num_tclassid_users++;
502#endif
503 nla = nla_find(attrs, attrlen, RTA_ENCAP);
504 if (nla) {
505 struct lwtunnel_state *lwtstate;
506 struct net_device *dev = NULL;
507 struct nlattr *nla_entype;
508
509 nla_entype = nla_find(attrs, attrlen,
510 RTA_ENCAP_TYPE);
511 if (!nla_entype)
512 goto err_inval;
513 if (cfg->fc_oif)
514 dev = __dev_get_by_index(net, cfg->fc_oif);
515 ret = lwtunnel_build_state(dev, nla_get_u16(
516 nla_entype),
517 nla, AF_INET, cfg,
518 &lwtstate);
519 if (ret)
520 goto errout;
521 nexthop_nh->nh_lwtstate =
522 lwtstate_get(lwtstate);
523 }
524 }
525
526 rtnh = rtnh_next(rtnh, &remaining);
527 } endfor_nexthops(fi);
528
529 return 0;
530
531err_inval:
532 ret = -EINVAL;
533
534errout:
535 return ret;
536}
537
538static void fib_rebalance(struct fib_info *fi)
539{
540 int total;
541 int w;
542 struct in_device *in_dev;
543
544 if (fi->fib_nhs < 2)
545 return;
546
547 total = 0;
548 for_nexthops(fi) {
549 if (nh->nh_flags & RTNH_F_DEAD)
550 continue;
551
552 in_dev = __in_dev_get_rtnl(nh->nh_dev);
553
554 if (in_dev &&
555 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
556 nh->nh_flags & RTNH_F_LINKDOWN)
557 continue;
558
559 total += nh->nh_weight;
560 } endfor_nexthops(fi);
561
562 w = 0;
563 change_nexthops(fi) {
564 int upper_bound;
565
566 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
567
568 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
569 upper_bound = -1;
570 } else if (in_dev &&
571 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
572 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
573 upper_bound = -1;
574 } else {
575 w += nexthop_nh->nh_weight;
576 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
577 total) - 1;
578 }
579
580 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
581 } endfor_nexthops(fi);
582
583 net_get_random_once(&fib_multipath_secret,
584 sizeof(fib_multipath_secret));
585}
586
587static inline void fib_add_weight(struct fib_info *fi,
588 const struct fib_nh *nh)
589{
590 fi->fib_weight += nh->nh_weight;
591}
592
593#else /* CONFIG_IP_ROUTE_MULTIPATH */
594
595#define fib_rebalance(fi) do { } while (0)
596#define fib_add_weight(fi, nh) do { } while (0)
597
598#endif /* CONFIG_IP_ROUTE_MULTIPATH */
599
600static int fib_encap_match(struct net *net, u16 encap_type,
601 struct nlattr *encap,
602 int oif, const struct fib_nh *nh,
603 const struct fib_config *cfg)
604{
605 struct lwtunnel_state *lwtstate;
606 struct net_device *dev = NULL;
607 int ret, result = 0;
608
609 if (encap_type == LWTUNNEL_ENCAP_NONE)
610 return 0;
611
612 if (oif)
613 dev = __dev_get_by_index(net, oif);
614 ret = lwtunnel_build_state(dev, encap_type, encap,
615 AF_INET, cfg, &lwtstate);
616 if (!ret) {
617 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
618 lwtstate_free(lwtstate);
619 }
620
621 return result;
622}
623
624int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
625{
626 struct net *net = cfg->fc_nlinfo.nl_net;
627#ifdef CONFIG_IP_ROUTE_MULTIPATH
628 struct rtnexthop *rtnh;
629 int remaining;
630#endif
631
632 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
633 return 1;
634
635 if (cfg->fc_oif || cfg->fc_gw) {
636 if (cfg->fc_encap) {
637 if (fib_encap_match(net, cfg->fc_encap_type,
638 cfg->fc_encap, cfg->fc_oif,
639 fi->fib_nh, cfg))
640 return 1;
641 }
642 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
643 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
644 return 0;
645 return 1;
646 }
647
648#ifdef CONFIG_IP_ROUTE_MULTIPATH
649 if (!cfg->fc_mp)
650 return 0;
651
652 rtnh = cfg->fc_mp;
653 remaining = cfg->fc_mp_len;
654
655 for_nexthops(fi) {
656 int attrlen;
657
658 if (!rtnh_ok(rtnh, remaining))
659 return -EINVAL;
660
661 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
662 return 1;
663
664 attrlen = rtnh_attrlen(rtnh);
665 if (attrlen > 0) {
666 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
667
668 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
669 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
670 return 1;
671#ifdef CONFIG_IP_ROUTE_CLASSID
672 nla = nla_find(attrs, attrlen, RTA_FLOW);
673 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
674 return 1;
675#endif
676 }
677
678 rtnh = rtnh_next(rtnh, &remaining);
679 } endfor_nexthops(fi);
680#endif
681 return 0;
682}
683
684
685/*
686 * Picture
687 * -------
688 *
689 * Semantics of nexthop is very messy by historical reasons.
690 * We have to take into account, that:
691 * a) gateway can be actually local interface address,
692 * so that gatewayed route is direct.
693 * b) gateway must be on-link address, possibly
694 * described not by an ifaddr, but also by a direct route.
695 * c) If both gateway and interface are specified, they should not
696 * contradict.
697 * d) If we use tunnel routes, gateway could be not on-link.
698 *
699 * Attempt to reconcile all of these (alas, self-contradictory) conditions
700 * results in pretty ugly and hairy code with obscure logic.
701 *
702 * I chose to generalized it instead, so that the size
703 * of code does not increase practically, but it becomes
704 * much more general.
705 * Every prefix is assigned a "scope" value: "host" is local address,
706 * "link" is direct route,
707 * [ ... "site" ... "interior" ... ]
708 * and "universe" is true gateway route with global meaning.
709 *
710 * Every prefix refers to a set of "nexthop"s (gw, oif),
711 * where gw must have narrower scope. This recursion stops
712 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
713 * which means that gw is forced to be on link.
714 *
715 * Code is still hairy, but now it is apparently logically
716 * consistent and very flexible. F.e. as by-product it allows
717 * to co-exists in peace independent exterior and interior
718 * routing processes.
719 *
720 * Normally it looks as following.
721 *
722 * {universe prefix} -> (gw, oif) [scope link]
723 * |
724 * |-> {link prefix} -> (gw, oif) [scope local]
725 * |
726 * |-> {local prefix} (terminal node)
727 */
728static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
729 struct fib_nh *nh)
730{
731 int err = 0;
732 struct net *net;
733 struct net_device *dev;
734
735 net = cfg->fc_nlinfo.nl_net;
736 if (nh->nh_gw) {
737 struct fib_result res;
738
739 if (nh->nh_flags & RTNH_F_ONLINK) {
740 unsigned int addr_type;
741
742 if (cfg->fc_scope >= RT_SCOPE_LINK)
743 return -EINVAL;
744 dev = __dev_get_by_index(net, nh->nh_oif);
745 if (!dev)
746 return -ENODEV;
747 if (!(dev->flags & IFF_UP))
748 return -ENETDOWN;
749 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
750 if (addr_type != RTN_UNICAST)
751 return -EINVAL;
752 if (!netif_carrier_ok(dev))
753 nh->nh_flags |= RTNH_F_LINKDOWN;
754 nh->nh_dev = dev;
755 dev_hold(dev);
756 nh->nh_scope = RT_SCOPE_LINK;
757 return 0;
758 }
759 rcu_read_lock();
760 {
761 struct fib_table *tbl = NULL;
762 struct flowi4 fl4 = {
763 .daddr = nh->nh_gw,
764 .flowi4_scope = cfg->fc_scope + 1,
765 .flowi4_oif = nh->nh_oif,
766 .flowi4_iif = LOOPBACK_IFINDEX,
767 };
768
769 /* It is not necessary, but requires a bit of thinking */
770 if (fl4.flowi4_scope < RT_SCOPE_LINK)
771 fl4.flowi4_scope = RT_SCOPE_LINK;
772
773 if (cfg->fc_table)
774 tbl = fib_get_table(net, cfg->fc_table);
775
776 if (tbl)
777 err = fib_table_lookup(tbl, &fl4, &res,
778 FIB_LOOKUP_IGNORE_LINKSTATE |
779 FIB_LOOKUP_NOREF);
780
781 /* on error or if no table given do full lookup. This
782 * is needed for example when nexthops are in the local
783 * table rather than the given table
784 */
785 if (!tbl || err) {
786 err = fib_lookup(net, &fl4, &res,
787 FIB_LOOKUP_IGNORE_LINKSTATE);
788 }
789
790 if (err) {
791 rcu_read_unlock();
792 return err;
793 }
794 }
795 err = -EINVAL;
796 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
797 goto out;
798 nh->nh_scope = res.scope;
799 nh->nh_oif = FIB_RES_OIF(res);
800 nh->nh_dev = dev = FIB_RES_DEV(res);
801 if (!dev)
802 goto out;
803 dev_hold(dev);
804 if (!netif_carrier_ok(dev))
805 nh->nh_flags |= RTNH_F_LINKDOWN;
806 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
807 } else {
808 struct in_device *in_dev;
809
810 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
811 return -EINVAL;
812
813 rcu_read_lock();
814 err = -ENODEV;
815 in_dev = inetdev_by_index(net, nh->nh_oif);
816 if (!in_dev)
817 goto out;
818 err = -ENETDOWN;
819 if (!(in_dev->dev->flags & IFF_UP))
820 goto out;
821 nh->nh_dev = in_dev->dev;
822 dev_hold(nh->nh_dev);
823 nh->nh_scope = RT_SCOPE_HOST;
824 if (!netif_carrier_ok(nh->nh_dev))
825 nh->nh_flags |= RTNH_F_LINKDOWN;
826 err = 0;
827 }
828out:
829 rcu_read_unlock();
830 return err;
831}
832
833static inline unsigned int fib_laddr_hashfn(__be32 val)
834{
835 unsigned int mask = (fib_info_hash_size - 1);
836
837 return ((__force u32)val ^
838 ((__force u32)val >> 7) ^
839 ((__force u32)val >> 14)) & mask;
840}
841
842static struct hlist_head *fib_info_hash_alloc(int bytes)
843{
844 if (bytes <= PAGE_SIZE)
845 return kzalloc(bytes, GFP_KERNEL);
846 else
847 return (struct hlist_head *)
848 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
849 get_order(bytes));
850}
851
852static void fib_info_hash_free(struct hlist_head *hash, int bytes)
853{
854 if (!hash)
855 return;
856
857 if (bytes <= PAGE_SIZE)
858 kfree(hash);
859 else
860 free_pages((unsigned long) hash, get_order(bytes));
861}
862
863static void fib_info_hash_move(struct hlist_head *new_info_hash,
864 struct hlist_head *new_laddrhash,
865 unsigned int new_size)
866{
867 struct hlist_head *old_info_hash, *old_laddrhash;
868 unsigned int old_size = fib_info_hash_size;
869 unsigned int i, bytes;
870
871 spin_lock_bh(&fib_info_lock);
872 old_info_hash = fib_info_hash;
873 old_laddrhash = fib_info_laddrhash;
874 fib_info_hash_size = new_size;
875
876 for (i = 0; i < old_size; i++) {
877 struct hlist_head *head = &fib_info_hash[i];
878 struct hlist_node *n;
879 struct fib_info *fi;
880
881 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
882 struct hlist_head *dest;
883 unsigned int new_hash;
884
885 new_hash = fib_info_hashfn(fi);
886 dest = &new_info_hash[new_hash];
887 hlist_add_head(&fi->fib_hash, dest);
888 }
889 }
890 fib_info_hash = new_info_hash;
891
892 for (i = 0; i < old_size; i++) {
893 struct hlist_head *lhead = &fib_info_laddrhash[i];
894 struct hlist_node *n;
895 struct fib_info *fi;
896
897 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
898 struct hlist_head *ldest;
899 unsigned int new_hash;
900
901 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
902 ldest = &new_laddrhash[new_hash];
903 hlist_add_head(&fi->fib_lhash, ldest);
904 }
905 }
906 fib_info_laddrhash = new_laddrhash;
907
908 spin_unlock_bh(&fib_info_lock);
909
910 bytes = old_size * sizeof(struct hlist_head *);
911 fib_info_hash_free(old_info_hash, bytes);
912 fib_info_hash_free(old_laddrhash, bytes);
913}
914
915__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
916{
917 nh->nh_saddr = inet_select_addr(nh->nh_dev,
918 nh->nh_gw,
919 nh->nh_parent->fib_scope);
920 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
921
922 return nh->nh_saddr;
923}
924
925static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
926{
927 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
928 fib_prefsrc != cfg->fc_dst) {
929 u32 tb_id = cfg->fc_table;
930 int rc;
931
932 if (tb_id == RT_TABLE_MAIN)
933 tb_id = RT_TABLE_LOCAL;
934
935 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
936 fib_prefsrc, tb_id);
937
938 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
939 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
940 fib_prefsrc, RT_TABLE_LOCAL);
941 }
942
943 if (rc != RTN_LOCAL)
944 return false;
945 }
946 return true;
947}
948
949static int
950fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
951{
952 bool ecn_ca = false;
953 struct nlattr *nla;
954 int remaining;
955
956 if (!cfg->fc_mx)
957 return 0;
958
959 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
960 int type = nla_type(nla);
961 u32 val;
962
963 if (!type)
964 continue;
965 if (type > RTAX_MAX)
966 return -EINVAL;
967
968 if (type == RTAX_CC_ALGO) {
969 char tmp[TCP_CA_NAME_MAX];
970
971 nla_strlcpy(tmp, nla, sizeof(tmp));
972 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
973 if (val == TCP_CA_UNSPEC)
974 return -EINVAL;
975 } else {
976 val = nla_get_u32(nla);
977 }
978 if (type == RTAX_ADVMSS && val > 65535 - 40)
979 val = 65535 - 40;
980 if (type == RTAX_MTU && val > 65535 - 15)
981 val = 65535 - 15;
982 if (type == RTAX_HOPLIMIT && val > 255)
983 val = 255;
984 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
985 return -EINVAL;
986 fi->fib_metrics[type - 1] = val;
987 }
988
989 if (ecn_ca)
990 fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
991
992 return 0;
993}
994
995struct fib_info *fib_create_info(struct fib_config *cfg)
996{
997 int err;
998 struct fib_info *fi = NULL;
999 struct fib_info *ofi;
1000 int nhs = 1;
1001 struct net *net = cfg->fc_nlinfo.nl_net;
1002
1003 if (cfg->fc_type > RTN_MAX)
1004 goto err_inval;
1005
1006 /* Fast check to catch the most weird cases */
1007 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
1008 goto err_inval;
1009
1010 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
1011 goto err_inval;
1012
1013#ifdef CONFIG_IP_ROUTE_MULTIPATH
1014 if (cfg->fc_mp) {
1015 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
1016 if (nhs == 0)
1017 goto err_inval;
1018 }
1019#endif
1020
1021 err = -ENOBUFS;
1022 if (fib_info_cnt >= fib_info_hash_size) {
1023 unsigned int new_size = fib_info_hash_size << 1;
1024 struct hlist_head *new_info_hash;
1025 struct hlist_head *new_laddrhash;
1026 unsigned int bytes;
1027
1028 if (!new_size)
1029 new_size = 16;
1030 bytes = new_size * sizeof(struct hlist_head *);
1031 new_info_hash = fib_info_hash_alloc(bytes);
1032 new_laddrhash = fib_info_hash_alloc(bytes);
1033 if (!new_info_hash || !new_laddrhash) {
1034 fib_info_hash_free(new_info_hash, bytes);
1035 fib_info_hash_free(new_laddrhash, bytes);
1036 } else
1037 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1038
1039 if (!fib_info_hash_size)
1040 goto failure;
1041 }
1042
1043 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1044 if (!fi)
1045 goto failure;
1046 fib_info_cnt++;
1047 if (cfg->fc_mx) {
1048 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
1049 if (!fi->fib_metrics)
1050 goto failure;
1051 } else
1052 fi->fib_metrics = (u32 *) dst_default_metrics;
1053
1054 fi->fib_net = net;
1055 fi->fib_protocol = cfg->fc_protocol;
1056 fi->fib_scope = cfg->fc_scope;
1057 fi->fib_flags = cfg->fc_flags;
1058 fi->fib_priority = cfg->fc_priority;
1059 fi->fib_prefsrc = cfg->fc_prefsrc;
1060 fi->fib_type = cfg->fc_type;
1061 fi->fib_tb_id = cfg->fc_table;
1062
1063 fi->fib_nhs = nhs;
1064 change_nexthops(fi) {
1065 nexthop_nh->nh_parent = fi;
1066 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1067 if (!nexthop_nh->nh_pcpu_rth_output)
1068 goto failure;
1069 } endfor_nexthops(fi)
1070
1071 err = fib_convert_metrics(fi, cfg);
1072 if (err)
1073 goto failure;
1074
1075 if (cfg->fc_mp) {
1076#ifdef CONFIG_IP_ROUTE_MULTIPATH
1077 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
1078 if (err != 0)
1079 goto failure;
1080 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
1081 goto err_inval;
1082 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
1083 goto err_inval;
1084#ifdef CONFIG_IP_ROUTE_CLASSID
1085 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
1086 goto err_inval;
1087#endif
1088#else
1089 goto err_inval;
1090#endif
1091 } else {
1092 struct fib_nh *nh = fi->fib_nh;
1093
1094 if (cfg->fc_encap) {
1095 struct lwtunnel_state *lwtstate;
1096 struct net_device *dev = NULL;
1097
1098 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE)
1099 goto err_inval;
1100 if (cfg->fc_oif)
1101 dev = __dev_get_by_index(net, cfg->fc_oif);
1102 err = lwtunnel_build_state(dev, cfg->fc_encap_type,
1103 cfg->fc_encap, AF_INET, cfg,
1104 &lwtstate);
1105 if (err)
1106 goto failure;
1107
1108 nh->nh_lwtstate = lwtstate_get(lwtstate);
1109 }
1110 nh->nh_oif = cfg->fc_oif;
1111 nh->nh_gw = cfg->fc_gw;
1112 nh->nh_flags = cfg->fc_flags;
1113#ifdef CONFIG_IP_ROUTE_CLASSID
1114 nh->nh_tclassid = cfg->fc_flow;
1115 if (nh->nh_tclassid)
1116 fi->fib_net->ipv4.fib_num_tclassid_users++;
1117#endif
1118#ifdef CONFIG_IP_ROUTE_MULTIPATH
1119 nh->nh_weight = 1;
1120#endif
1121 }
1122
1123 if (fib_props[cfg->fc_type].error) {
1124 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
1125 goto err_inval;
1126 goto link_it;
1127 } else {
1128 switch (cfg->fc_type) {
1129 case RTN_UNICAST:
1130 case RTN_LOCAL:
1131 case RTN_BROADCAST:
1132 case RTN_ANYCAST:
1133 case RTN_MULTICAST:
1134 break;
1135 default:
1136 goto err_inval;
1137 }
1138 }
1139
1140 if (cfg->fc_scope > RT_SCOPE_HOST)
1141 goto err_inval;
1142
1143 if (cfg->fc_scope == RT_SCOPE_HOST) {
1144 struct fib_nh *nh = fi->fib_nh;
1145
1146 /* Local address is added. */
1147 if (nhs != 1 || nh->nh_gw)
1148 goto err_inval;
1149 nh->nh_scope = RT_SCOPE_NOWHERE;
1150 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1151 err = -ENODEV;
1152 if (!nh->nh_dev)
1153 goto failure;
1154 } else {
1155 int linkdown = 0;
1156
1157 change_nexthops(fi) {
1158 err = fib_check_nh(cfg, fi, nexthop_nh);
1159 if (err != 0)
1160 goto failure;
1161 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1162 linkdown++;
1163 } endfor_nexthops(fi)
1164 if (linkdown == fi->fib_nhs)
1165 fi->fib_flags |= RTNH_F_LINKDOWN;
1166 }
1167
1168 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc))
1169 goto err_inval;
1170
1171 change_nexthops(fi) {
1172 fib_info_update_nh_saddr(net, nexthop_nh);
1173 fib_add_weight(fi, nexthop_nh);
1174 } endfor_nexthops(fi)
1175
1176 fib_rebalance(fi);
1177
1178link_it:
1179 ofi = fib_find_info(fi);
1180 if (ofi) {
1181 fi->fib_dead = 1;
1182 free_fib_info(fi);
1183 ofi->fib_treeref++;
1184 return ofi;
1185 }
1186
1187 fi->fib_treeref++;
1188 atomic_inc(&fi->fib_clntref);
1189 spin_lock_bh(&fib_info_lock);
1190 hlist_add_head(&fi->fib_hash,
1191 &fib_info_hash[fib_info_hashfn(fi)]);
1192 if (fi->fib_prefsrc) {
1193 struct hlist_head *head;
1194
1195 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1196 hlist_add_head(&fi->fib_lhash, head);
1197 }
1198 change_nexthops(fi) {
1199 struct hlist_head *head;
1200 unsigned int hash;
1201
1202 if (!nexthop_nh->nh_dev)
1203 continue;
1204 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1205 head = &fib_info_devhash[hash];
1206 hlist_add_head(&nexthop_nh->nh_hash, head);
1207 } endfor_nexthops(fi)
1208 spin_unlock_bh(&fib_info_lock);
1209 return fi;
1210
1211err_inval:
1212 err = -EINVAL;
1213
1214failure:
1215 if (fi) {
1216 fi->fib_dead = 1;
1217 free_fib_info(fi);
1218 }
1219
1220 return ERR_PTR(err);
1221}
1222
1223int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1224 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1225 struct fib_info *fi, unsigned int flags)
1226{
1227 struct nlmsghdr *nlh;
1228 struct rtmsg *rtm;
1229
1230 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1231 if (!nlh)
1232 return -EMSGSIZE;
1233
1234 rtm = nlmsg_data(nlh);
1235 rtm->rtm_family = AF_INET;
1236 rtm->rtm_dst_len = dst_len;
1237 rtm->rtm_src_len = 0;
1238 rtm->rtm_tos = tos;
1239 if (tb_id < 256)
1240 rtm->rtm_table = tb_id;
1241 else
1242 rtm->rtm_table = RT_TABLE_COMPAT;
1243 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1244 goto nla_put_failure;
1245 rtm->rtm_type = type;
1246 rtm->rtm_flags = fi->fib_flags;
1247 rtm->rtm_scope = fi->fib_scope;
1248 rtm->rtm_protocol = fi->fib_protocol;
1249
1250 if (rtm->rtm_dst_len &&
1251 nla_put_in_addr(skb, RTA_DST, dst))
1252 goto nla_put_failure;
1253 if (fi->fib_priority &&
1254 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1255 goto nla_put_failure;
1256 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
1257 goto nla_put_failure;
1258
1259 if (fi->fib_prefsrc &&
1260 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1261 goto nla_put_failure;
1262 if (fi->fib_nhs == 1) {
1263 struct in_device *in_dev;
1264
1265 if (fi->fib_nh->nh_gw &&
1266 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1267 goto nla_put_failure;
1268 if (fi->fib_nh->nh_oif &&
1269 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1270 goto nla_put_failure;
1271 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1272 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev);
1273 if (in_dev &&
1274 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1275 rtm->rtm_flags |= RTNH_F_DEAD;
1276 }
1277#ifdef CONFIG_IP_ROUTE_CLASSID
1278 if (fi->fib_nh[0].nh_tclassid &&
1279 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1280 goto nla_put_failure;
1281#endif
1282 if (fi->fib_nh->nh_lwtstate &&
1283 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1284 goto nla_put_failure;
1285 }
1286#ifdef CONFIG_IP_ROUTE_MULTIPATH
1287 if (fi->fib_nhs > 1) {
1288 struct rtnexthop *rtnh;
1289 struct nlattr *mp;
1290
1291 mp = nla_nest_start(skb, RTA_MULTIPATH);
1292 if (!mp)
1293 goto nla_put_failure;
1294
1295 for_nexthops(fi) {
1296 struct in_device *in_dev;
1297
1298 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1299 if (!rtnh)
1300 goto nla_put_failure;
1301
1302 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1303 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1304 in_dev = __in_dev_get_rtnl(nh->nh_dev);
1305 if (in_dev &&
1306 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1307 rtnh->rtnh_flags |= RTNH_F_DEAD;
1308 }
1309 rtnh->rtnh_hops = nh->nh_weight - 1;
1310 rtnh->rtnh_ifindex = nh->nh_oif;
1311
1312 if (nh->nh_gw &&
1313 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1314 goto nla_put_failure;
1315#ifdef CONFIG_IP_ROUTE_CLASSID
1316 if (nh->nh_tclassid &&
1317 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1318 goto nla_put_failure;
1319#endif
1320 if (nh->nh_lwtstate &&
1321 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1322 goto nla_put_failure;
1323
1324 /* length of rtnetlink header + attributes */
1325 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1326 } endfor_nexthops(fi);
1327
1328 nla_nest_end(skb, mp);
1329 }
1330#endif
1331 nlmsg_end(skb, nlh);
1332 return 0;
1333
1334nla_put_failure:
1335 nlmsg_cancel(skb, nlh);
1336 return -EMSGSIZE;
1337}
1338
1339/*
1340 * Update FIB if:
1341 * - local address disappeared -> we must delete all the entries
1342 * referring to it.
1343 * - device went down -> we must shutdown all nexthops going via it.
1344 */
1345int fib_sync_down_addr(struct net_device *dev, __be32 local)
1346{
1347 int ret = 0;
1348 unsigned int hash = fib_laddr_hashfn(local);
1349 struct hlist_head *head = &fib_info_laddrhash[hash];
1350 struct net *net = dev_net(dev);
1351 int tb_id = l3mdev_fib_table(dev);
1352 struct fib_info *fi;
1353
1354 if (!fib_info_laddrhash || local == 0)
1355 return 0;
1356
1357 hlist_for_each_entry(fi, head, fib_lhash) {
1358 if (!net_eq(fi->fib_net, net) ||
1359 fi->fib_tb_id != tb_id)
1360 continue;
1361 if (fi->fib_prefsrc == local) {
1362 fi->fib_flags |= RTNH_F_DEAD;
1363 ret++;
1364 }
1365 }
1366 return ret;
1367}
1368
1369/* Event force Flags Description
1370 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1371 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1372 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1373 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1374 */
1375int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1376{
1377 int ret = 0;
1378 int scope = RT_SCOPE_NOWHERE;
1379 struct fib_info *prev_fi = NULL;
1380 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1381 struct hlist_head *head = &fib_info_devhash[hash];
1382 struct fib_nh *nh;
1383
1384 if (force)
1385 scope = -1;
1386
1387 hlist_for_each_entry(nh, head, nh_hash) {
1388 struct fib_info *fi = nh->nh_parent;
1389 int dead;
1390
1391 BUG_ON(!fi->fib_nhs);
1392 if (nh->nh_dev != dev || fi == prev_fi)
1393 continue;
1394 prev_fi = fi;
1395 dead = 0;
1396 change_nexthops(fi) {
1397 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1398 dead++;
1399 else if (nexthop_nh->nh_dev == dev &&
1400 nexthop_nh->nh_scope != scope) {
1401 switch (event) {
1402 case NETDEV_DOWN:
1403 case NETDEV_UNREGISTER:
1404 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1405 /* fall through */
1406 case NETDEV_CHANGE:
1407 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1408 break;
1409 }
1410 dead++;
1411 }
1412#ifdef CONFIG_IP_ROUTE_MULTIPATH
1413 if (event == NETDEV_UNREGISTER &&
1414 nexthop_nh->nh_dev == dev) {
1415 dead = fi->fib_nhs;
1416 break;
1417 }
1418#endif
1419 } endfor_nexthops(fi)
1420 if (dead == fi->fib_nhs) {
1421 switch (event) {
1422 case NETDEV_DOWN:
1423 case NETDEV_UNREGISTER:
1424 fi->fib_flags |= RTNH_F_DEAD;
1425 /* fall through */
1426 case NETDEV_CHANGE:
1427 fi->fib_flags |= RTNH_F_LINKDOWN;
1428 break;
1429 }
1430 ret++;
1431 }
1432
1433 fib_rebalance(fi);
1434 }
1435
1436 return ret;
1437}
1438
1439/* Must be invoked inside of an RCU protected region. */
1440void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1441{
1442 struct fib_info *fi = NULL, *last_resort = NULL;
1443 struct hlist_head *fa_head = res->fa_head;
1444 struct fib_table *tb = res->table;
1445 u8 slen = 32 - res->prefixlen;
1446 int order = -1, last_idx = -1;
1447 struct fib_alias *fa, *fa1 = NULL;
1448 u32 last_prio = res->fi->fib_priority;
1449 u8 last_tos = 0;
1450
1451 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1452 struct fib_info *next_fi = fa->fa_info;
1453
1454 if (fa->fa_slen != slen)
1455 continue;
1456 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1457 continue;
1458 if (fa->tb_id != tb->tb_id)
1459 continue;
1460 if (next_fi->fib_priority > last_prio &&
1461 fa->fa_tos == last_tos) {
1462 if (last_tos)
1463 continue;
1464 break;
1465 }
1466 if (next_fi->fib_flags & RTNH_F_DEAD)
1467 continue;
1468 last_tos = fa->fa_tos;
1469 last_prio = next_fi->fib_priority;
1470
1471 if (next_fi->fib_scope != res->scope ||
1472 fa->fa_type != RTN_UNICAST)
1473 continue;
1474 if (!next_fi->fib_nh[0].nh_gw ||
1475 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1476 continue;
1477
1478 fib_alias_accessed(fa);
1479
1480 if (!fi) {
1481 if (next_fi != res->fi)
1482 break;
1483 fa1 = fa;
1484 } else if (!fib_detect_death(fi, order, &last_resort,
1485 &last_idx, fa1->fa_default)) {
1486 fib_result_assign(res, fi);
1487 fa1->fa_default = order;
1488 goto out;
1489 }
1490 fi = next_fi;
1491 order++;
1492 }
1493
1494 if (order <= 0 || !fi) {
1495 if (fa1)
1496 fa1->fa_default = -1;
1497 goto out;
1498 }
1499
1500 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1501 fa1->fa_default)) {
1502 fib_result_assign(res, fi);
1503 fa1->fa_default = order;
1504 goto out;
1505 }
1506
1507 if (last_idx >= 0)
1508 fib_result_assign(res, last_resort);
1509 fa1->fa_default = last_idx;
1510out:
1511 return;
1512}
1513
1514/*
1515 * Dead device goes up. We wake up dead nexthops.
1516 * It takes sense only on multipath routes.
1517 */
1518int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1519{
1520 struct fib_info *prev_fi;
1521 unsigned int hash;
1522 struct hlist_head *head;
1523 struct fib_nh *nh;
1524 int ret;
1525
1526 if (!(dev->flags & IFF_UP))
1527 return 0;
1528
1529 if (nh_flags & RTNH_F_DEAD) {
1530 unsigned int flags = dev_get_flags(dev);
1531
1532 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1533 nh_flags |= RTNH_F_LINKDOWN;
1534 }
1535
1536 prev_fi = NULL;
1537 hash = fib_devindex_hashfn(dev->ifindex);
1538 head = &fib_info_devhash[hash];
1539 ret = 0;
1540
1541 hlist_for_each_entry(nh, head, nh_hash) {
1542 struct fib_info *fi = nh->nh_parent;
1543 int alive;
1544
1545 BUG_ON(!fi->fib_nhs);
1546 if (nh->nh_dev != dev || fi == prev_fi)
1547 continue;
1548
1549 prev_fi = fi;
1550 alive = 0;
1551 change_nexthops(fi) {
1552 if (!(nexthop_nh->nh_flags & nh_flags)) {
1553 alive++;
1554 continue;
1555 }
1556 if (!nexthop_nh->nh_dev ||
1557 !(nexthop_nh->nh_dev->flags & IFF_UP))
1558 continue;
1559 if (nexthop_nh->nh_dev != dev ||
1560 !__in_dev_get_rtnl(dev))
1561 continue;
1562 alive++;
1563 nexthop_nh->nh_flags &= ~nh_flags;
1564 } endfor_nexthops(fi)
1565
1566 if (alive > 0) {
1567 fi->fib_flags &= ~nh_flags;
1568 ret++;
1569 }
1570
1571 fib_rebalance(fi);
1572 }
1573
1574 return ret;
1575}
1576
1577#ifdef CONFIG_IP_ROUTE_MULTIPATH
1578static bool fib_good_nh(const struct fib_nh *nh)
1579{
1580 int state = NUD_REACHABLE;
1581
1582 if (nh->nh_scope == RT_SCOPE_LINK) {
1583 struct neighbour *n;
1584
1585 rcu_read_lock_bh();
1586
1587 n = __ipv4_neigh_lookup_noref(nh->nh_dev,
1588 (__force u32)nh->nh_gw);
1589 if (n)
1590 state = n->nud_state;
1591
1592 rcu_read_unlock_bh();
1593 }
1594
1595 return !!(state & NUD_VALID);
1596}
1597
1598void fib_select_multipath(struct fib_result *res, int hash)
1599{
1600 struct fib_info *fi = res->fi;
1601 struct net *net = fi->fib_net;
1602 bool first = false;
1603
1604 for_nexthops(fi) {
1605 if (hash > atomic_read(&nh->nh_upper_bound))
1606 continue;
1607
1608 if (!net->ipv4.sysctl_fib_multipath_use_neigh ||
1609 fib_good_nh(nh)) {
1610 res->nh_sel = nhsel;
1611 return;
1612 }
1613 if (!first) {
1614 res->nh_sel = nhsel;
1615 first = true;
1616 }
1617 } endfor_nexthops(fi);
1618}
1619#endif
1620
1621void fib_select_path(struct net *net, struct fib_result *res,
1622 struct flowi4 *fl4, int mp_hash)
1623{
1624 bool oif_check;
1625
1626 oif_check = (fl4->flowi4_oif == 0 ||
1627 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
1628
1629#ifdef CONFIG_IP_ROUTE_MULTIPATH
1630 if (res->fi->fib_nhs > 1 && oif_check) {
1631 if (mp_hash < 0)
1632 mp_hash = get_hash_from_flowi4(fl4) >> 1;
1633
1634 fib_select_multipath(res, mp_hash);
1635 }
1636 else
1637#endif
1638 if (!res->prefixlen &&
1639 res->table->tb_num_default > 1 &&
1640 res->type == RTN_UNICAST && oif_check)
1641 fib_select_default(fl4, res);
1642
1643 if (!fl4->saddr)
1644 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1645}
1646EXPORT_SYMBOL_GPL(fib_select_path);