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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 <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#include <linux/netlink.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#include <net/lwtunnel.h>
47#include <net/fib_notifier.h>
48
49#include "fib_lookup.h"
50
51static DEFINE_SPINLOCK(fib_info_lock);
52static struct hlist_head *fib_info_hash;
53static struct hlist_head *fib_info_laddrhash;
54static unsigned int fib_info_hash_size;
55static unsigned int fib_info_cnt;
56
57#define DEVINDEX_HASHBITS 8
58#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
59static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
60
61#ifdef CONFIG_IP_ROUTE_MULTIPATH
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
93const 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
144static void rt_fibinfo_free(struct rtable __rcu **rtp)
145{
146 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
147
148 if (!rt)
149 return;
150
151 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
152 * because we waited an RCU grace period before calling
153 * free_fib_info_rcu()
154 */
155
156 dst_dev_put(&rt->dst);
157 dst_release_immediate(&rt->dst);
158}
159
160static void free_nh_exceptions(struct fib_nh *nh)
161{
162 struct fnhe_hash_bucket *hash;
163 int i;
164
165 hash = rcu_dereference_protected(nh->nh_exceptions, 1);
166 if (!hash)
167 return;
168 for (i = 0; i < FNHE_HASH_SIZE; i++) {
169 struct fib_nh_exception *fnhe;
170
171 fnhe = rcu_dereference_protected(hash[i].chain, 1);
172 while (fnhe) {
173 struct fib_nh_exception *next;
174
175 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
176
177 rt_fibinfo_free(&fnhe->fnhe_rth_input);
178 rt_fibinfo_free(&fnhe->fnhe_rth_output);
179
180 kfree(fnhe);
181
182 fnhe = next;
183 }
184 }
185 kfree(hash);
186}
187
188static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
189{
190 int cpu;
191
192 if (!rtp)
193 return;
194
195 for_each_possible_cpu(cpu) {
196 struct rtable *rt;
197
198 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
199 if (rt) {
200 dst_dev_put(&rt->dst);
201 dst_release_immediate(&rt->dst);
202 }
203 }
204 free_percpu(rtp);
205}
206
207/* Release a nexthop info record */
208static void free_fib_info_rcu(struct rcu_head *head)
209{
210 struct fib_info *fi = container_of(head, struct fib_info, rcu);
211 struct dst_metrics *m;
212
213 change_nexthops(fi) {
214 if (nexthop_nh->nh_dev)
215 dev_put(nexthop_nh->nh_dev);
216 lwtstate_put(nexthop_nh->nh_lwtstate);
217 free_nh_exceptions(nexthop_nh);
218 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
219 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
220 } endfor_nexthops(fi);
221
222 m = fi->fib_metrics;
223 if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
224 kfree(m);
225 kfree(fi);
226}
227
228void free_fib_info(struct fib_info *fi)
229{
230 if (fi->fib_dead == 0) {
231 pr_warn("Freeing alive fib_info %p\n", fi);
232 return;
233 }
234 fib_info_cnt--;
235#ifdef CONFIG_IP_ROUTE_CLASSID
236 change_nexthops(fi) {
237 if (nexthop_nh->nh_tclassid)
238 fi->fib_net->ipv4.fib_num_tclassid_users--;
239 } endfor_nexthops(fi);
240#endif
241 call_rcu(&fi->rcu, free_fib_info_rcu);
242}
243EXPORT_SYMBOL_GPL(free_fib_info);
244
245void fib_release_info(struct fib_info *fi)
246{
247 spin_lock_bh(&fib_info_lock);
248 if (fi && --fi->fib_treeref == 0) {
249 hlist_del(&fi->fib_hash);
250 if (fi->fib_prefsrc)
251 hlist_del(&fi->fib_lhash);
252 change_nexthops(fi) {
253 if (!nexthop_nh->nh_dev)
254 continue;
255 hlist_del(&nexthop_nh->nh_hash);
256 } endfor_nexthops(fi)
257 fi->fib_dead = 1;
258 fib_info_put(fi);
259 }
260 spin_unlock_bh(&fib_info_lock);
261}
262
263static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
264{
265 const struct fib_nh *onh = ofi->fib_nh;
266
267 for_nexthops(fi) {
268 if (nh->nh_oif != onh->nh_oif ||
269 nh->nh_gw != onh->nh_gw ||
270 nh->nh_scope != onh->nh_scope ||
271#ifdef CONFIG_IP_ROUTE_MULTIPATH
272 nh->nh_weight != onh->nh_weight ||
273#endif
274#ifdef CONFIG_IP_ROUTE_CLASSID
275 nh->nh_tclassid != onh->nh_tclassid ||
276#endif
277 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
278 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
279 return -1;
280 onh++;
281 } endfor_nexthops(fi);
282 return 0;
283}
284
285static inline unsigned int fib_devindex_hashfn(unsigned int val)
286{
287 unsigned int mask = DEVINDEX_HASHSIZE - 1;
288
289 return (val ^
290 (val >> DEVINDEX_HASHBITS) ^
291 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
292}
293
294static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
295{
296 unsigned int mask = (fib_info_hash_size - 1);
297 unsigned int val = fi->fib_nhs;
298
299 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
300 val ^= (__force u32)fi->fib_prefsrc;
301 val ^= fi->fib_priority;
302 for_nexthops(fi) {
303 val ^= fib_devindex_hashfn(nh->nh_oif);
304 } endfor_nexthops(fi)
305
306 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
307}
308
309static struct fib_info *fib_find_info(const struct fib_info *nfi)
310{
311 struct hlist_head *head;
312 struct fib_info *fi;
313 unsigned int hash;
314
315 hash = fib_info_hashfn(nfi);
316 head = &fib_info_hash[hash];
317
318 hlist_for_each_entry(fi, head, fib_hash) {
319 if (!net_eq(fi->fib_net, nfi->fib_net))
320 continue;
321 if (fi->fib_nhs != nfi->fib_nhs)
322 continue;
323 if (nfi->fib_protocol == fi->fib_protocol &&
324 nfi->fib_scope == fi->fib_scope &&
325 nfi->fib_prefsrc == fi->fib_prefsrc &&
326 nfi->fib_priority == fi->fib_priority &&
327 nfi->fib_type == fi->fib_type &&
328 memcmp(nfi->fib_metrics, fi->fib_metrics,
329 sizeof(u32) * RTAX_MAX) == 0 &&
330 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
331 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
332 return fi;
333 }
334
335 return NULL;
336}
337
338/* Check, that the gateway is already configured.
339 * Used only by redirect accept routine.
340 */
341int ip_fib_check_default(__be32 gw, struct net_device *dev)
342{
343 struct hlist_head *head;
344 struct fib_nh *nh;
345 unsigned int hash;
346
347 spin_lock(&fib_info_lock);
348
349 hash = fib_devindex_hashfn(dev->ifindex);
350 head = &fib_info_devhash[hash];
351 hlist_for_each_entry(nh, head, nh_hash) {
352 if (nh->nh_dev == dev &&
353 nh->nh_gw == gw &&
354 !(nh->nh_flags & RTNH_F_DEAD)) {
355 spin_unlock(&fib_info_lock);
356 return 0;
357 }
358 }
359
360 spin_unlock(&fib_info_lock);
361
362 return -1;
363}
364
365static inline size_t fib_nlmsg_size(struct fib_info *fi)
366{
367 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
368 + nla_total_size(4) /* RTA_TABLE */
369 + nla_total_size(4) /* RTA_DST */
370 + nla_total_size(4) /* RTA_PRIORITY */
371 + nla_total_size(4) /* RTA_PREFSRC */
372 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
373
374 /* space for nested metrics */
375 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
376
377 if (fi->fib_nhs) {
378 size_t nh_encapsize = 0;
379 /* Also handles the special case fib_nhs == 1 */
380
381 /* each nexthop is packed in an attribute */
382 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
383
384 /* may contain flow and gateway attribute */
385 nhsize += 2 * nla_total_size(4);
386
387 /* grab encap info */
388 for_nexthops(fi) {
389 if (nh->nh_lwtstate) {
390 /* RTA_ENCAP_TYPE */
391 nh_encapsize += lwtunnel_get_encap_size(
392 nh->nh_lwtstate);
393 /* RTA_ENCAP */
394 nh_encapsize += nla_total_size(2);
395 }
396 } endfor_nexthops(fi);
397
398 /* all nexthops are packed in a nested attribute */
399 payload += nla_total_size((fi->fib_nhs * nhsize) +
400 nh_encapsize);
401
402 }
403
404 return payload;
405}
406
407void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
408 int dst_len, u32 tb_id, const struct nl_info *info,
409 unsigned int nlm_flags)
410{
411 struct sk_buff *skb;
412 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
413 int err = -ENOBUFS;
414
415 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
416 if (!skb)
417 goto errout;
418
419 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
420 fa->fa_type, key, dst_len,
421 fa->fa_tos, fa->fa_info, nlm_flags);
422 if (err < 0) {
423 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
424 WARN_ON(err == -EMSGSIZE);
425 kfree_skb(skb);
426 goto errout;
427 }
428 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
429 info->nlh, GFP_KERNEL);
430 return;
431errout:
432 if (err < 0)
433 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
434}
435
436static int fib_detect_death(struct fib_info *fi, int order,
437 struct fib_info **last_resort, int *last_idx,
438 int dflt)
439{
440 struct neighbour *n;
441 int state = NUD_NONE;
442
443 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
444 if (n) {
445 state = n->nud_state;
446 neigh_release(n);
447 } else {
448 return 0;
449 }
450 if (state == NUD_REACHABLE)
451 return 0;
452 if ((state & NUD_VALID) && order != dflt)
453 return 0;
454 if ((state & NUD_VALID) ||
455 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
456 *last_resort = fi;
457 *last_idx = order;
458 }
459 return 1;
460}
461
462#ifdef CONFIG_IP_ROUTE_MULTIPATH
463
464static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
465 struct netlink_ext_ack *extack)
466{
467 int nhs = 0;
468
469 while (rtnh_ok(rtnh, remaining)) {
470 nhs++;
471 rtnh = rtnh_next(rtnh, &remaining);
472 }
473
474 /* leftover implies invalid nexthop configuration, discard it */
475 if (remaining > 0) {
476 NL_SET_ERR_MSG(extack,
477 "Invalid nexthop configuration - extra data after nexthops");
478 nhs = 0;
479 }
480
481 return nhs;
482}
483
484static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
485 int remaining, struct fib_config *cfg,
486 struct netlink_ext_ack *extack)
487{
488 int ret;
489
490 change_nexthops(fi) {
491 int attrlen;
492
493 if (!rtnh_ok(rtnh, remaining)) {
494 NL_SET_ERR_MSG(extack,
495 "Invalid nexthop configuration - extra data after nexthop");
496 return -EINVAL;
497 }
498
499 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
500 NL_SET_ERR_MSG(extack,
501 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
502 return -EINVAL;
503 }
504
505 nexthop_nh->nh_flags =
506 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
507 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
508 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
509
510 attrlen = rtnh_attrlen(rtnh);
511 if (attrlen > 0) {
512 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
513
514 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
515 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
516#ifdef CONFIG_IP_ROUTE_CLASSID
517 nla = nla_find(attrs, attrlen, RTA_FLOW);
518 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
519 if (nexthop_nh->nh_tclassid)
520 fi->fib_net->ipv4.fib_num_tclassid_users++;
521#endif
522 nla = nla_find(attrs, attrlen, RTA_ENCAP);
523 if (nla) {
524 struct lwtunnel_state *lwtstate;
525 struct nlattr *nla_entype;
526
527 nla_entype = nla_find(attrs, attrlen,
528 RTA_ENCAP_TYPE);
529 if (!nla_entype) {
530 NL_SET_BAD_ATTR(extack, nla);
531 NL_SET_ERR_MSG(extack,
532 "Encap type is missing");
533 goto err_inval;
534 }
535
536 ret = lwtunnel_build_state(nla_get_u16(
537 nla_entype),
538 nla, AF_INET, cfg,
539 &lwtstate, extack);
540 if (ret)
541 goto errout;
542 nexthop_nh->nh_lwtstate =
543 lwtstate_get(lwtstate);
544 }
545 }
546
547 rtnh = rtnh_next(rtnh, &remaining);
548 } endfor_nexthops(fi);
549
550 return 0;
551
552err_inval:
553 ret = -EINVAL;
554
555errout:
556 return ret;
557}
558
559static void fib_rebalance(struct fib_info *fi)
560{
561 int total;
562 int w;
563 struct in_device *in_dev;
564
565 if (fi->fib_nhs < 2)
566 return;
567
568 total = 0;
569 for_nexthops(fi) {
570 if (nh->nh_flags & RTNH_F_DEAD)
571 continue;
572
573 in_dev = __in_dev_get_rtnl(nh->nh_dev);
574
575 if (in_dev &&
576 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
577 nh->nh_flags & RTNH_F_LINKDOWN)
578 continue;
579
580 total += nh->nh_weight;
581 } endfor_nexthops(fi);
582
583 w = 0;
584 change_nexthops(fi) {
585 int upper_bound;
586
587 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
588
589 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
590 upper_bound = -1;
591 } else if (in_dev &&
592 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
593 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
594 upper_bound = -1;
595 } else {
596 w += nexthop_nh->nh_weight;
597 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
598 total) - 1;
599 }
600
601 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
602 } endfor_nexthops(fi);
603}
604#else /* CONFIG_IP_ROUTE_MULTIPATH */
605
606#define fib_rebalance(fi) do { } while (0)
607
608#endif /* CONFIG_IP_ROUTE_MULTIPATH */
609
610static int fib_encap_match(u16 encap_type,
611 struct nlattr *encap,
612 const struct fib_nh *nh,
613 const struct fib_config *cfg,
614 struct netlink_ext_ack *extack)
615{
616 struct lwtunnel_state *lwtstate;
617 int ret, result = 0;
618
619 if (encap_type == LWTUNNEL_ENCAP_NONE)
620 return 0;
621
622 ret = lwtunnel_build_state(encap_type, encap, AF_INET,
623 cfg, &lwtstate, extack);
624 if (!ret) {
625 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
626 lwtstate_free(lwtstate);
627 }
628
629 return result;
630}
631
632int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
633 struct netlink_ext_ack *extack)
634{
635#ifdef CONFIG_IP_ROUTE_MULTIPATH
636 struct rtnexthop *rtnh;
637 int remaining;
638#endif
639
640 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
641 return 1;
642
643 if (cfg->fc_oif || cfg->fc_gw) {
644 if (cfg->fc_encap) {
645 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
646 fi->fib_nh, cfg, extack))
647 return 1;
648 }
649#ifdef CONFIG_IP_ROUTE_CLASSID
650 if (cfg->fc_flow &&
651 cfg->fc_flow != fi->fib_nh->nh_tclassid)
652 return 1;
653#endif
654 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
655 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
656 return 0;
657 return 1;
658 }
659
660#ifdef CONFIG_IP_ROUTE_MULTIPATH
661 if (!cfg->fc_mp)
662 return 0;
663
664 rtnh = cfg->fc_mp;
665 remaining = cfg->fc_mp_len;
666
667 for_nexthops(fi) {
668 int attrlen;
669
670 if (!rtnh_ok(rtnh, remaining))
671 return -EINVAL;
672
673 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
674 return 1;
675
676 attrlen = rtnh_attrlen(rtnh);
677 if (attrlen > 0) {
678 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
679
680 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
681 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
682 return 1;
683#ifdef CONFIG_IP_ROUTE_CLASSID
684 nla = nla_find(attrs, attrlen, RTA_FLOW);
685 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
686 return 1;
687#endif
688 }
689
690 rtnh = rtnh_next(rtnh, &remaining);
691 } endfor_nexthops(fi);
692#endif
693 return 0;
694}
695
696bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
697{
698 struct nlattr *nla;
699 int remaining;
700
701 if (!cfg->fc_mx)
702 return true;
703
704 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
705 int type = nla_type(nla);
706 u32 fi_val, val;
707
708 if (!type)
709 continue;
710 if (type > RTAX_MAX)
711 return false;
712
713 if (type == RTAX_CC_ALGO) {
714 char tmp[TCP_CA_NAME_MAX];
715 bool ecn_ca = false;
716
717 nla_strlcpy(tmp, nla, sizeof(tmp));
718 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
719 } else {
720 val = nla_get_u32(nla);
721 }
722
723 fi_val = fi->fib_metrics->metrics[type - 1];
724 if (type == RTAX_FEATURES)
725 fi_val &= ~DST_FEATURE_ECN_CA;
726
727 if (fi_val != val)
728 return false;
729 }
730
731 return true;
732}
733
734
735/*
736 * Picture
737 * -------
738 *
739 * Semantics of nexthop is very messy by historical reasons.
740 * We have to take into account, that:
741 * a) gateway can be actually local interface address,
742 * so that gatewayed route is direct.
743 * b) gateway must be on-link address, possibly
744 * described not by an ifaddr, but also by a direct route.
745 * c) If both gateway and interface are specified, they should not
746 * contradict.
747 * d) If we use tunnel routes, gateway could be not on-link.
748 *
749 * Attempt to reconcile all of these (alas, self-contradictory) conditions
750 * results in pretty ugly and hairy code with obscure logic.
751 *
752 * I chose to generalized it instead, so that the size
753 * of code does not increase practically, but it becomes
754 * much more general.
755 * Every prefix is assigned a "scope" value: "host" is local address,
756 * "link" is direct route,
757 * [ ... "site" ... "interior" ... ]
758 * and "universe" is true gateway route with global meaning.
759 *
760 * Every prefix refers to a set of "nexthop"s (gw, oif),
761 * where gw must have narrower scope. This recursion stops
762 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
763 * which means that gw is forced to be on link.
764 *
765 * Code is still hairy, but now it is apparently logically
766 * consistent and very flexible. F.e. as by-product it allows
767 * to co-exists in peace independent exterior and interior
768 * routing processes.
769 *
770 * Normally it looks as following.
771 *
772 * {universe prefix} -> (gw, oif) [scope link]
773 * |
774 * |-> {link prefix} -> (gw, oif) [scope local]
775 * |
776 * |-> {local prefix} (terminal node)
777 */
778static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh,
779 struct netlink_ext_ack *extack)
780{
781 int err = 0;
782 struct net *net;
783 struct net_device *dev;
784
785 net = cfg->fc_nlinfo.nl_net;
786 if (nh->nh_gw) {
787 struct fib_result res;
788
789 if (nh->nh_flags & RTNH_F_ONLINK) {
790 unsigned int addr_type;
791
792 if (cfg->fc_scope >= RT_SCOPE_LINK) {
793 NL_SET_ERR_MSG(extack,
794 "Nexthop has invalid scope");
795 return -EINVAL;
796 }
797 dev = __dev_get_by_index(net, nh->nh_oif);
798 if (!dev)
799 return -ENODEV;
800 if (!(dev->flags & IFF_UP)) {
801 NL_SET_ERR_MSG(extack,
802 "Nexthop device is not up");
803 return -ENETDOWN;
804 }
805 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
806 if (addr_type != RTN_UNICAST) {
807 NL_SET_ERR_MSG(extack,
808 "Nexthop has invalid gateway");
809 return -EINVAL;
810 }
811 if (!netif_carrier_ok(dev))
812 nh->nh_flags |= RTNH_F_LINKDOWN;
813 nh->nh_dev = dev;
814 dev_hold(dev);
815 nh->nh_scope = RT_SCOPE_LINK;
816 return 0;
817 }
818 rcu_read_lock();
819 {
820 struct fib_table *tbl = NULL;
821 struct flowi4 fl4 = {
822 .daddr = nh->nh_gw,
823 .flowi4_scope = cfg->fc_scope + 1,
824 .flowi4_oif = nh->nh_oif,
825 .flowi4_iif = LOOPBACK_IFINDEX,
826 };
827
828 /* It is not necessary, but requires a bit of thinking */
829 if (fl4.flowi4_scope < RT_SCOPE_LINK)
830 fl4.flowi4_scope = RT_SCOPE_LINK;
831
832 if (cfg->fc_table)
833 tbl = fib_get_table(net, cfg->fc_table);
834
835 if (tbl)
836 err = fib_table_lookup(tbl, &fl4, &res,
837 FIB_LOOKUP_IGNORE_LINKSTATE |
838 FIB_LOOKUP_NOREF);
839
840 /* on error or if no table given do full lookup. This
841 * is needed for example when nexthops are in the local
842 * table rather than the given table
843 */
844 if (!tbl || err) {
845 err = fib_lookup(net, &fl4, &res,
846 FIB_LOOKUP_IGNORE_LINKSTATE);
847 }
848
849 if (err) {
850 NL_SET_ERR_MSG(extack,
851 "Nexthop has invalid gateway");
852 rcu_read_unlock();
853 return err;
854 }
855 }
856 err = -EINVAL;
857 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
858 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
859 goto out;
860 }
861 nh->nh_scope = res.scope;
862 nh->nh_oif = FIB_RES_OIF(res);
863 nh->nh_dev = dev = FIB_RES_DEV(res);
864 if (!dev) {
865 NL_SET_ERR_MSG(extack,
866 "No egress device for nexthop gateway");
867 goto out;
868 }
869 dev_hold(dev);
870 if (!netif_carrier_ok(dev))
871 nh->nh_flags |= RTNH_F_LINKDOWN;
872 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
873 } else {
874 struct in_device *in_dev;
875
876 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
877 NL_SET_ERR_MSG(extack,
878 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
879 return -EINVAL;
880 }
881 rcu_read_lock();
882 err = -ENODEV;
883 in_dev = inetdev_by_index(net, nh->nh_oif);
884 if (!in_dev)
885 goto out;
886 err = -ENETDOWN;
887 if (!(in_dev->dev->flags & IFF_UP)) {
888 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
889 goto out;
890 }
891 nh->nh_dev = in_dev->dev;
892 dev_hold(nh->nh_dev);
893 nh->nh_scope = RT_SCOPE_HOST;
894 if (!netif_carrier_ok(nh->nh_dev))
895 nh->nh_flags |= RTNH_F_LINKDOWN;
896 err = 0;
897 }
898out:
899 rcu_read_unlock();
900 return err;
901}
902
903static inline unsigned int fib_laddr_hashfn(__be32 val)
904{
905 unsigned int mask = (fib_info_hash_size - 1);
906
907 return ((__force u32)val ^
908 ((__force u32)val >> 7) ^
909 ((__force u32)val >> 14)) & mask;
910}
911
912static struct hlist_head *fib_info_hash_alloc(int bytes)
913{
914 if (bytes <= PAGE_SIZE)
915 return kzalloc(bytes, GFP_KERNEL);
916 else
917 return (struct hlist_head *)
918 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
919 get_order(bytes));
920}
921
922static void fib_info_hash_free(struct hlist_head *hash, int bytes)
923{
924 if (!hash)
925 return;
926
927 if (bytes <= PAGE_SIZE)
928 kfree(hash);
929 else
930 free_pages((unsigned long) hash, get_order(bytes));
931}
932
933static void fib_info_hash_move(struct hlist_head *new_info_hash,
934 struct hlist_head *new_laddrhash,
935 unsigned int new_size)
936{
937 struct hlist_head *old_info_hash, *old_laddrhash;
938 unsigned int old_size = fib_info_hash_size;
939 unsigned int i, bytes;
940
941 spin_lock_bh(&fib_info_lock);
942 old_info_hash = fib_info_hash;
943 old_laddrhash = fib_info_laddrhash;
944 fib_info_hash_size = new_size;
945
946 for (i = 0; i < old_size; i++) {
947 struct hlist_head *head = &fib_info_hash[i];
948 struct hlist_node *n;
949 struct fib_info *fi;
950
951 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
952 struct hlist_head *dest;
953 unsigned int new_hash;
954
955 new_hash = fib_info_hashfn(fi);
956 dest = &new_info_hash[new_hash];
957 hlist_add_head(&fi->fib_hash, dest);
958 }
959 }
960 fib_info_hash = new_info_hash;
961
962 for (i = 0; i < old_size; i++) {
963 struct hlist_head *lhead = &fib_info_laddrhash[i];
964 struct hlist_node *n;
965 struct fib_info *fi;
966
967 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
968 struct hlist_head *ldest;
969 unsigned int new_hash;
970
971 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
972 ldest = &new_laddrhash[new_hash];
973 hlist_add_head(&fi->fib_lhash, ldest);
974 }
975 }
976 fib_info_laddrhash = new_laddrhash;
977
978 spin_unlock_bh(&fib_info_lock);
979
980 bytes = old_size * sizeof(struct hlist_head *);
981 fib_info_hash_free(old_info_hash, bytes);
982 fib_info_hash_free(old_laddrhash, bytes);
983}
984
985__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
986{
987 nh->nh_saddr = inet_select_addr(nh->nh_dev,
988 nh->nh_gw,
989 nh->nh_parent->fib_scope);
990 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
991
992 return nh->nh_saddr;
993}
994
995static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
996{
997 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
998 fib_prefsrc != cfg->fc_dst) {
999 u32 tb_id = cfg->fc_table;
1000 int rc;
1001
1002 if (tb_id == RT_TABLE_MAIN)
1003 tb_id = RT_TABLE_LOCAL;
1004
1005 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1006 fib_prefsrc, tb_id);
1007
1008 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1009 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1010 fib_prefsrc, RT_TABLE_LOCAL);
1011 }
1012
1013 if (rc != RTN_LOCAL)
1014 return false;
1015 }
1016 return true;
1017}
1018
1019static int
1020fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
1021{
1022 bool ecn_ca = false;
1023 struct nlattr *nla;
1024 int remaining;
1025
1026 if (!cfg->fc_mx)
1027 return 0;
1028
1029 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1030 int type = nla_type(nla);
1031 u32 val;
1032
1033 if (!type)
1034 continue;
1035 if (type > RTAX_MAX)
1036 return -EINVAL;
1037
1038 if (type == RTAX_CC_ALGO) {
1039 char tmp[TCP_CA_NAME_MAX];
1040
1041 nla_strlcpy(tmp, nla, sizeof(tmp));
1042 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1043 if (val == TCP_CA_UNSPEC)
1044 return -EINVAL;
1045 } else {
1046 val = nla_get_u32(nla);
1047 }
1048 if (type == RTAX_ADVMSS && val > 65535 - 40)
1049 val = 65535 - 40;
1050 if (type == RTAX_MTU && val > 65535 - 15)
1051 val = 65535 - 15;
1052 if (type == RTAX_HOPLIMIT && val > 255)
1053 val = 255;
1054 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
1055 return -EINVAL;
1056 fi->fib_metrics->metrics[type - 1] = val;
1057 }
1058
1059 if (ecn_ca)
1060 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
1061
1062 return 0;
1063}
1064
1065struct fib_info *fib_create_info(struct fib_config *cfg,
1066 struct netlink_ext_ack *extack)
1067{
1068 int err;
1069 struct fib_info *fi = NULL;
1070 struct fib_info *ofi;
1071 int nhs = 1;
1072 struct net *net = cfg->fc_nlinfo.nl_net;
1073
1074 if (cfg->fc_type > RTN_MAX)
1075 goto err_inval;
1076
1077 /* Fast check to catch the most weird cases */
1078 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1079 NL_SET_ERR_MSG(extack, "Invalid scope");
1080 goto err_inval;
1081 }
1082
1083 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1084 NL_SET_ERR_MSG(extack,
1085 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1086 goto err_inval;
1087 }
1088
1089#ifdef CONFIG_IP_ROUTE_MULTIPATH
1090 if (cfg->fc_mp) {
1091 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1092 if (nhs == 0)
1093 goto err_inval;
1094 }
1095#endif
1096
1097 err = -ENOBUFS;
1098 if (fib_info_cnt >= fib_info_hash_size) {
1099 unsigned int new_size = fib_info_hash_size << 1;
1100 struct hlist_head *new_info_hash;
1101 struct hlist_head *new_laddrhash;
1102 unsigned int bytes;
1103
1104 if (!new_size)
1105 new_size = 16;
1106 bytes = new_size * sizeof(struct hlist_head *);
1107 new_info_hash = fib_info_hash_alloc(bytes);
1108 new_laddrhash = fib_info_hash_alloc(bytes);
1109 if (!new_info_hash || !new_laddrhash) {
1110 fib_info_hash_free(new_info_hash, bytes);
1111 fib_info_hash_free(new_laddrhash, bytes);
1112 } else
1113 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1114
1115 if (!fib_info_hash_size)
1116 goto failure;
1117 }
1118
1119 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1120 if (!fi)
1121 goto failure;
1122 if (cfg->fc_mx) {
1123 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
1124 if (unlikely(!fi->fib_metrics)) {
1125 kfree(fi);
1126 return ERR_PTR(err);
1127 }
1128 refcount_set(&fi->fib_metrics->refcnt, 1);
1129 } else {
1130 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
1131 }
1132 fib_info_cnt++;
1133 fi->fib_net = net;
1134 fi->fib_protocol = cfg->fc_protocol;
1135 fi->fib_scope = cfg->fc_scope;
1136 fi->fib_flags = cfg->fc_flags;
1137 fi->fib_priority = cfg->fc_priority;
1138 fi->fib_prefsrc = cfg->fc_prefsrc;
1139 fi->fib_type = cfg->fc_type;
1140 fi->fib_tb_id = cfg->fc_table;
1141
1142 fi->fib_nhs = nhs;
1143 change_nexthops(fi) {
1144 nexthop_nh->nh_parent = fi;
1145 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1146 if (!nexthop_nh->nh_pcpu_rth_output)
1147 goto failure;
1148 } endfor_nexthops(fi)
1149
1150 err = fib_convert_metrics(fi, cfg);
1151 if (err)
1152 goto failure;
1153
1154 if (cfg->fc_mp) {
1155#ifdef CONFIG_IP_ROUTE_MULTIPATH
1156 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1157 if (err != 0)
1158 goto failure;
1159 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
1160 NL_SET_ERR_MSG(extack,
1161 "Nexthop device index does not match RTA_OIF");
1162 goto err_inval;
1163 }
1164 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
1165 NL_SET_ERR_MSG(extack,
1166 "Nexthop gateway does not match RTA_GATEWAY");
1167 goto err_inval;
1168 }
1169#ifdef CONFIG_IP_ROUTE_CLASSID
1170 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
1171 NL_SET_ERR_MSG(extack,
1172 "Nexthop class id does not match RTA_FLOW");
1173 goto err_inval;
1174 }
1175#endif
1176#else
1177 NL_SET_ERR_MSG(extack,
1178 "Multipath support not enabled in kernel");
1179 goto err_inval;
1180#endif
1181 } else {
1182 struct fib_nh *nh = fi->fib_nh;
1183
1184 if (cfg->fc_encap) {
1185 struct lwtunnel_state *lwtstate;
1186
1187 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
1188 NL_SET_ERR_MSG(extack,
1189 "LWT encap type not specified");
1190 goto err_inval;
1191 }
1192 err = lwtunnel_build_state(cfg->fc_encap_type,
1193 cfg->fc_encap, AF_INET, cfg,
1194 &lwtstate, extack);
1195 if (err)
1196 goto failure;
1197
1198 nh->nh_lwtstate = lwtstate_get(lwtstate);
1199 }
1200 nh->nh_oif = cfg->fc_oif;
1201 nh->nh_gw = cfg->fc_gw;
1202 nh->nh_flags = cfg->fc_flags;
1203#ifdef CONFIG_IP_ROUTE_CLASSID
1204 nh->nh_tclassid = cfg->fc_flow;
1205 if (nh->nh_tclassid)
1206 fi->fib_net->ipv4.fib_num_tclassid_users++;
1207#endif
1208#ifdef CONFIG_IP_ROUTE_MULTIPATH
1209 nh->nh_weight = 1;
1210#endif
1211 }
1212
1213 if (fib_props[cfg->fc_type].error) {
1214 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) {
1215 NL_SET_ERR_MSG(extack,
1216 "Gateway, device and multipath can not be specified for this route type");
1217 goto err_inval;
1218 }
1219 goto link_it;
1220 } else {
1221 switch (cfg->fc_type) {
1222 case RTN_UNICAST:
1223 case RTN_LOCAL:
1224 case RTN_BROADCAST:
1225 case RTN_ANYCAST:
1226 case RTN_MULTICAST:
1227 break;
1228 default:
1229 NL_SET_ERR_MSG(extack, "Invalid route type");
1230 goto err_inval;
1231 }
1232 }
1233
1234 if (cfg->fc_scope > RT_SCOPE_HOST) {
1235 NL_SET_ERR_MSG(extack, "Invalid scope");
1236 goto err_inval;
1237 }
1238
1239 if (cfg->fc_scope == RT_SCOPE_HOST) {
1240 struct fib_nh *nh = fi->fib_nh;
1241
1242 /* Local address is added. */
1243 if (nhs != 1) {
1244 NL_SET_ERR_MSG(extack,
1245 "Route with host scope can not have multiple nexthops");
1246 goto err_inval;
1247 }
1248 if (nh->nh_gw) {
1249 NL_SET_ERR_MSG(extack,
1250 "Route with host scope can not have a gateway");
1251 goto err_inval;
1252 }
1253 nh->nh_scope = RT_SCOPE_NOWHERE;
1254 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1255 err = -ENODEV;
1256 if (!nh->nh_dev)
1257 goto failure;
1258 } else {
1259 int linkdown = 0;
1260
1261 change_nexthops(fi) {
1262 err = fib_check_nh(cfg, nexthop_nh, extack);
1263 if (err != 0)
1264 goto failure;
1265 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1266 linkdown++;
1267 } endfor_nexthops(fi)
1268 if (linkdown == fi->fib_nhs)
1269 fi->fib_flags |= RTNH_F_LINKDOWN;
1270 }
1271
1272 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1273 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1274 goto err_inval;
1275 }
1276
1277 change_nexthops(fi) {
1278 fib_info_update_nh_saddr(net, nexthop_nh);
1279 } endfor_nexthops(fi)
1280
1281 fib_rebalance(fi);
1282
1283link_it:
1284 ofi = fib_find_info(fi);
1285 if (ofi) {
1286 fi->fib_dead = 1;
1287 free_fib_info(fi);
1288 ofi->fib_treeref++;
1289 return ofi;
1290 }
1291
1292 fi->fib_treeref++;
1293 refcount_set(&fi->fib_clntref, 1);
1294 spin_lock_bh(&fib_info_lock);
1295 hlist_add_head(&fi->fib_hash,
1296 &fib_info_hash[fib_info_hashfn(fi)]);
1297 if (fi->fib_prefsrc) {
1298 struct hlist_head *head;
1299
1300 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1301 hlist_add_head(&fi->fib_lhash, head);
1302 }
1303 change_nexthops(fi) {
1304 struct hlist_head *head;
1305 unsigned int hash;
1306
1307 if (!nexthop_nh->nh_dev)
1308 continue;
1309 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1310 head = &fib_info_devhash[hash];
1311 hlist_add_head(&nexthop_nh->nh_hash, head);
1312 } endfor_nexthops(fi)
1313 spin_unlock_bh(&fib_info_lock);
1314 return fi;
1315
1316err_inval:
1317 err = -EINVAL;
1318
1319failure:
1320 if (fi) {
1321 fi->fib_dead = 1;
1322 free_fib_info(fi);
1323 }
1324
1325 return ERR_PTR(err);
1326}
1327
1328int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1329 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1330 struct fib_info *fi, unsigned int flags)
1331{
1332 struct nlmsghdr *nlh;
1333 struct rtmsg *rtm;
1334
1335 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1336 if (!nlh)
1337 return -EMSGSIZE;
1338
1339 rtm = nlmsg_data(nlh);
1340 rtm->rtm_family = AF_INET;
1341 rtm->rtm_dst_len = dst_len;
1342 rtm->rtm_src_len = 0;
1343 rtm->rtm_tos = tos;
1344 if (tb_id < 256)
1345 rtm->rtm_table = tb_id;
1346 else
1347 rtm->rtm_table = RT_TABLE_COMPAT;
1348 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1349 goto nla_put_failure;
1350 rtm->rtm_type = type;
1351 rtm->rtm_flags = fi->fib_flags;
1352 rtm->rtm_scope = fi->fib_scope;
1353 rtm->rtm_protocol = fi->fib_protocol;
1354
1355 if (rtm->rtm_dst_len &&
1356 nla_put_in_addr(skb, RTA_DST, dst))
1357 goto nla_put_failure;
1358 if (fi->fib_priority &&
1359 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1360 goto nla_put_failure;
1361 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1362 goto nla_put_failure;
1363
1364 if (fi->fib_prefsrc &&
1365 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1366 goto nla_put_failure;
1367 if (fi->fib_nhs == 1) {
1368 if (fi->fib_nh->nh_gw &&
1369 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1370 goto nla_put_failure;
1371 if (fi->fib_nh->nh_oif &&
1372 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1373 goto nla_put_failure;
1374 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1375 struct in_device *in_dev;
1376
1377 rcu_read_lock();
1378 in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev);
1379 if (in_dev &&
1380 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1381 rtm->rtm_flags |= RTNH_F_DEAD;
1382 rcu_read_unlock();
1383 }
1384 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD)
1385 rtm->rtm_flags |= RTNH_F_OFFLOAD;
1386#ifdef CONFIG_IP_ROUTE_CLASSID
1387 if (fi->fib_nh[0].nh_tclassid &&
1388 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1389 goto nla_put_failure;
1390#endif
1391 if (fi->fib_nh->nh_lwtstate &&
1392 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1393 goto nla_put_failure;
1394 }
1395#ifdef CONFIG_IP_ROUTE_MULTIPATH
1396 if (fi->fib_nhs > 1) {
1397 struct rtnexthop *rtnh;
1398 struct nlattr *mp;
1399
1400 mp = nla_nest_start(skb, RTA_MULTIPATH);
1401 if (!mp)
1402 goto nla_put_failure;
1403
1404 for_nexthops(fi) {
1405 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1406 if (!rtnh)
1407 goto nla_put_failure;
1408
1409 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1410 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1411 struct in_device *in_dev;
1412
1413 rcu_read_lock();
1414 in_dev = __in_dev_get_rcu(nh->nh_dev);
1415 if (in_dev &&
1416 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1417 rtnh->rtnh_flags |= RTNH_F_DEAD;
1418 rcu_read_unlock();
1419 }
1420 rtnh->rtnh_hops = nh->nh_weight - 1;
1421 rtnh->rtnh_ifindex = nh->nh_oif;
1422
1423 if (nh->nh_gw &&
1424 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1425 goto nla_put_failure;
1426#ifdef CONFIG_IP_ROUTE_CLASSID
1427 if (nh->nh_tclassid &&
1428 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1429 goto nla_put_failure;
1430#endif
1431 if (nh->nh_lwtstate &&
1432 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1433 goto nla_put_failure;
1434
1435 /* length of rtnetlink header + attributes */
1436 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1437 } endfor_nexthops(fi);
1438
1439 nla_nest_end(skb, mp);
1440 }
1441#endif
1442 nlmsg_end(skb, nlh);
1443 return 0;
1444
1445nla_put_failure:
1446 nlmsg_cancel(skb, nlh);
1447 return -EMSGSIZE;
1448}
1449
1450/*
1451 * Update FIB if:
1452 * - local address disappeared -> we must delete all the entries
1453 * referring to it.
1454 * - device went down -> we must shutdown all nexthops going via it.
1455 */
1456int fib_sync_down_addr(struct net_device *dev, __be32 local)
1457{
1458 int ret = 0;
1459 unsigned int hash = fib_laddr_hashfn(local);
1460 struct hlist_head *head = &fib_info_laddrhash[hash];
1461 struct net *net = dev_net(dev);
1462 int tb_id = l3mdev_fib_table(dev);
1463 struct fib_info *fi;
1464
1465 if (!fib_info_laddrhash || local == 0)
1466 return 0;
1467
1468 hlist_for_each_entry(fi, head, fib_lhash) {
1469 if (!net_eq(fi->fib_net, net) ||
1470 fi->fib_tb_id != tb_id)
1471 continue;
1472 if (fi->fib_prefsrc == local) {
1473 fi->fib_flags |= RTNH_F_DEAD;
1474 ret++;
1475 }
1476 }
1477 return ret;
1478}
1479
1480static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
1481 enum fib_event_type event_type)
1482{
1483 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
1484 struct fib_nh_notifier_info info = {
1485 .fib_nh = fib_nh,
1486 };
1487
1488 switch (event_type) {
1489 case FIB_EVENT_NH_ADD:
1490 if (fib_nh->nh_flags & RTNH_F_DEAD)
1491 break;
1492 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1493 fib_nh->nh_flags & RTNH_F_LINKDOWN)
1494 break;
1495 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type,
1496 &info.info);
1497 case FIB_EVENT_NH_DEL:
1498 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1499 fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
1500 (fib_nh->nh_flags & RTNH_F_DEAD))
1501 return call_fib4_notifiers(dev_net(fib_nh->nh_dev),
1502 event_type, &info.info);
1503 default:
1504 break;
1505 }
1506
1507 return NOTIFY_DONE;
1508}
1509
1510/* Event force Flags Description
1511 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1512 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1513 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1514 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1515 */
1516int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1517{
1518 int ret = 0;
1519 int scope = RT_SCOPE_NOWHERE;
1520 struct fib_info *prev_fi = NULL;
1521 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1522 struct hlist_head *head = &fib_info_devhash[hash];
1523 struct fib_nh *nh;
1524
1525 if (force)
1526 scope = -1;
1527
1528 hlist_for_each_entry(nh, head, nh_hash) {
1529 struct fib_info *fi = nh->nh_parent;
1530 int dead;
1531
1532 BUG_ON(!fi->fib_nhs);
1533 if (nh->nh_dev != dev || fi == prev_fi)
1534 continue;
1535 prev_fi = fi;
1536 dead = 0;
1537 change_nexthops(fi) {
1538 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1539 dead++;
1540 else if (nexthop_nh->nh_dev == dev &&
1541 nexthop_nh->nh_scope != scope) {
1542 switch (event) {
1543 case NETDEV_DOWN:
1544 case NETDEV_UNREGISTER:
1545 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1546 /* fall through */
1547 case NETDEV_CHANGE:
1548 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1549 break;
1550 }
1551 call_fib_nh_notifiers(nexthop_nh,
1552 FIB_EVENT_NH_DEL);
1553 dead++;
1554 }
1555#ifdef CONFIG_IP_ROUTE_MULTIPATH
1556 if (event == NETDEV_UNREGISTER &&
1557 nexthop_nh->nh_dev == dev) {
1558 dead = fi->fib_nhs;
1559 break;
1560 }
1561#endif
1562 } endfor_nexthops(fi)
1563 if (dead == fi->fib_nhs) {
1564 switch (event) {
1565 case NETDEV_DOWN:
1566 case NETDEV_UNREGISTER:
1567 fi->fib_flags |= RTNH_F_DEAD;
1568 /* fall through */
1569 case NETDEV_CHANGE:
1570 fi->fib_flags |= RTNH_F_LINKDOWN;
1571 break;
1572 }
1573 ret++;
1574 }
1575
1576 fib_rebalance(fi);
1577 }
1578
1579 return ret;
1580}
1581
1582/* Must be invoked inside of an RCU protected region. */
1583static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1584{
1585 struct fib_info *fi = NULL, *last_resort = NULL;
1586 struct hlist_head *fa_head = res->fa_head;
1587 struct fib_table *tb = res->table;
1588 u8 slen = 32 - res->prefixlen;
1589 int order = -1, last_idx = -1;
1590 struct fib_alias *fa, *fa1 = NULL;
1591 u32 last_prio = res->fi->fib_priority;
1592 u8 last_tos = 0;
1593
1594 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1595 struct fib_info *next_fi = fa->fa_info;
1596
1597 if (fa->fa_slen != slen)
1598 continue;
1599 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1600 continue;
1601 if (fa->tb_id != tb->tb_id)
1602 continue;
1603 if (next_fi->fib_priority > last_prio &&
1604 fa->fa_tos == last_tos) {
1605 if (last_tos)
1606 continue;
1607 break;
1608 }
1609 if (next_fi->fib_flags & RTNH_F_DEAD)
1610 continue;
1611 last_tos = fa->fa_tos;
1612 last_prio = next_fi->fib_priority;
1613
1614 if (next_fi->fib_scope != res->scope ||
1615 fa->fa_type != RTN_UNICAST)
1616 continue;
1617 if (!next_fi->fib_nh[0].nh_gw ||
1618 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1619 continue;
1620
1621 fib_alias_accessed(fa);
1622
1623 if (!fi) {
1624 if (next_fi != res->fi)
1625 break;
1626 fa1 = fa;
1627 } else if (!fib_detect_death(fi, order, &last_resort,
1628 &last_idx, fa1->fa_default)) {
1629 fib_result_assign(res, fi);
1630 fa1->fa_default = order;
1631 goto out;
1632 }
1633 fi = next_fi;
1634 order++;
1635 }
1636
1637 if (order <= 0 || !fi) {
1638 if (fa1)
1639 fa1->fa_default = -1;
1640 goto out;
1641 }
1642
1643 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1644 fa1->fa_default)) {
1645 fib_result_assign(res, fi);
1646 fa1->fa_default = order;
1647 goto out;
1648 }
1649
1650 if (last_idx >= 0)
1651 fib_result_assign(res, last_resort);
1652 fa1->fa_default = last_idx;
1653out:
1654 return;
1655}
1656
1657/*
1658 * Dead device goes up. We wake up dead nexthops.
1659 * It takes sense only on multipath routes.
1660 */
1661int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1662{
1663 struct fib_info *prev_fi;
1664 unsigned int hash;
1665 struct hlist_head *head;
1666 struct fib_nh *nh;
1667 int ret;
1668
1669 if (!(dev->flags & IFF_UP))
1670 return 0;
1671
1672 if (nh_flags & RTNH_F_DEAD) {
1673 unsigned int flags = dev_get_flags(dev);
1674
1675 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1676 nh_flags |= RTNH_F_LINKDOWN;
1677 }
1678
1679 prev_fi = NULL;
1680 hash = fib_devindex_hashfn(dev->ifindex);
1681 head = &fib_info_devhash[hash];
1682 ret = 0;
1683
1684 hlist_for_each_entry(nh, head, nh_hash) {
1685 struct fib_info *fi = nh->nh_parent;
1686 int alive;
1687
1688 BUG_ON(!fi->fib_nhs);
1689 if (nh->nh_dev != dev || fi == prev_fi)
1690 continue;
1691
1692 prev_fi = fi;
1693 alive = 0;
1694 change_nexthops(fi) {
1695 if (!(nexthop_nh->nh_flags & nh_flags)) {
1696 alive++;
1697 continue;
1698 }
1699 if (!nexthop_nh->nh_dev ||
1700 !(nexthop_nh->nh_dev->flags & IFF_UP))
1701 continue;
1702 if (nexthop_nh->nh_dev != dev ||
1703 !__in_dev_get_rtnl(dev))
1704 continue;
1705 alive++;
1706 nexthop_nh->nh_flags &= ~nh_flags;
1707 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1708 } endfor_nexthops(fi)
1709
1710 if (alive > 0) {
1711 fi->fib_flags &= ~nh_flags;
1712 ret++;
1713 }
1714
1715 fib_rebalance(fi);
1716 }
1717
1718 return ret;
1719}
1720
1721#ifdef CONFIG_IP_ROUTE_MULTIPATH
1722static bool fib_good_nh(const struct fib_nh *nh)
1723{
1724 int state = NUD_REACHABLE;
1725
1726 if (nh->nh_scope == RT_SCOPE_LINK) {
1727 struct neighbour *n;
1728
1729 rcu_read_lock_bh();
1730
1731 n = __ipv4_neigh_lookup_noref(nh->nh_dev,
1732 (__force u32)nh->nh_gw);
1733 if (n)
1734 state = n->nud_state;
1735
1736 rcu_read_unlock_bh();
1737 }
1738
1739 return !!(state & NUD_VALID);
1740}
1741
1742void fib_select_multipath(struct fib_result *res, int hash)
1743{
1744 struct fib_info *fi = res->fi;
1745 struct net *net = fi->fib_net;
1746 bool first = false;
1747
1748 for_nexthops(fi) {
1749 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
1750 if (!fib_good_nh(nh))
1751 continue;
1752 if (!first) {
1753 res->nh_sel = nhsel;
1754 first = true;
1755 }
1756 }
1757
1758 if (hash > atomic_read(&nh->nh_upper_bound))
1759 continue;
1760
1761 res->nh_sel = nhsel;
1762 return;
1763 } endfor_nexthops(fi);
1764}
1765#endif
1766
1767void fib_select_path(struct net *net, struct fib_result *res,
1768 struct flowi4 *fl4, const struct sk_buff *skb)
1769{
1770 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
1771 goto check_saddr;
1772
1773#ifdef CONFIG_IP_ROUTE_MULTIPATH
1774 if (res->fi->fib_nhs > 1) {
1775 int h = fib_multipath_hash(net, fl4, skb, NULL);
1776
1777 fib_select_multipath(res, h);
1778 }
1779 else
1780#endif
1781 if (!res->prefixlen &&
1782 res->table->tb_num_default > 1 &&
1783 res->type == RTN_UNICAST)
1784 fib_select_default(fl4, res);
1785
1786check_saddr:
1787 if (!fl4->saddr)
1788 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1789}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: semantics.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12#include <linux/uaccess.h>
13#include <linux/bitops.h>
14#include <linux/types.h>
15#include <linux/kernel.h>
16#include <linux/jiffies.h>
17#include <linux/mm.h>
18#include <linux/string.h>
19#include <linux/socket.h>
20#include <linux/sockios.h>
21#include <linux/errno.h>
22#include <linux/in.h>
23#include <linux/inet.h>
24#include <linux/inetdevice.h>
25#include <linux/netdevice.h>
26#include <linux/if_arp.h>
27#include <linux/proc_fs.h>
28#include <linux/skbuff.h>
29#include <linux/init.h>
30#include <linux/slab.h>
31#include <linux/netlink.h>
32
33#include <net/arp.h>
34#include <net/ip.h>
35#include <net/protocol.h>
36#include <net/route.h>
37#include <net/tcp.h>
38#include <net/sock.h>
39#include <net/ip_fib.h>
40#include <net/ip6_fib.h>
41#include <net/nexthop.h>
42#include <net/netlink.h>
43#include <net/rtnh.h>
44#include <net/lwtunnel.h>
45#include <net/fib_notifier.h>
46#include <net/addrconf.h>
47
48#include "fib_lookup.h"
49
50static DEFINE_SPINLOCK(fib_info_lock);
51static struct hlist_head *fib_info_hash;
52static struct hlist_head *fib_info_laddrhash;
53static unsigned int fib_info_hash_size;
54static unsigned int fib_info_cnt;
55
56#define DEVINDEX_HASHBITS 8
57#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
58static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
59
60/* for_nexthops and change_nexthops only used when nexthop object
61 * is not set in a fib_info. The logic within can reference fib_nh.
62 */
63#ifdef CONFIG_IP_ROUTE_MULTIPATH
64
65#define for_nexthops(fi) { \
66 int nhsel; const struct fib_nh *nh; \
67 for (nhsel = 0, nh = (fi)->fib_nh; \
68 nhsel < fib_info_num_path((fi)); \
69 nh++, nhsel++)
70
71#define change_nexthops(fi) { \
72 int nhsel; struct fib_nh *nexthop_nh; \
73 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
74 nhsel < fib_info_num_path((fi)); \
75 nexthop_nh++, nhsel++)
76
77#else /* CONFIG_IP_ROUTE_MULTIPATH */
78
79/* Hope, that gcc will optimize it to get rid of dummy loop */
80
81#define for_nexthops(fi) { \
82 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
83 for (nhsel = 0; nhsel < 1; nhsel++)
84
85#define change_nexthops(fi) { \
86 int nhsel; \
87 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
88 for (nhsel = 0; nhsel < 1; nhsel++)
89
90#endif /* CONFIG_IP_ROUTE_MULTIPATH */
91
92#define endfor_nexthops(fi) }
93
94
95const struct fib_prop fib_props[RTN_MAX + 1] = {
96 [RTN_UNSPEC] = {
97 .error = 0,
98 .scope = RT_SCOPE_NOWHERE,
99 },
100 [RTN_UNICAST] = {
101 .error = 0,
102 .scope = RT_SCOPE_UNIVERSE,
103 },
104 [RTN_LOCAL] = {
105 .error = 0,
106 .scope = RT_SCOPE_HOST,
107 },
108 [RTN_BROADCAST] = {
109 .error = 0,
110 .scope = RT_SCOPE_LINK,
111 },
112 [RTN_ANYCAST] = {
113 .error = 0,
114 .scope = RT_SCOPE_LINK,
115 },
116 [RTN_MULTICAST] = {
117 .error = 0,
118 .scope = RT_SCOPE_UNIVERSE,
119 },
120 [RTN_BLACKHOLE] = {
121 .error = -EINVAL,
122 .scope = RT_SCOPE_UNIVERSE,
123 },
124 [RTN_UNREACHABLE] = {
125 .error = -EHOSTUNREACH,
126 .scope = RT_SCOPE_UNIVERSE,
127 },
128 [RTN_PROHIBIT] = {
129 .error = -EACCES,
130 .scope = RT_SCOPE_UNIVERSE,
131 },
132 [RTN_THROW] = {
133 .error = -EAGAIN,
134 .scope = RT_SCOPE_UNIVERSE,
135 },
136 [RTN_NAT] = {
137 .error = -EINVAL,
138 .scope = RT_SCOPE_NOWHERE,
139 },
140 [RTN_XRESOLVE] = {
141 .error = -EINVAL,
142 .scope = RT_SCOPE_NOWHERE,
143 },
144};
145
146static void rt_fibinfo_free(struct rtable __rcu **rtp)
147{
148 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
149
150 if (!rt)
151 return;
152
153 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
154 * because we waited an RCU grace period before calling
155 * free_fib_info_rcu()
156 */
157
158 dst_dev_put(&rt->dst);
159 dst_release_immediate(&rt->dst);
160}
161
162static void free_nh_exceptions(struct fib_nh_common *nhc)
163{
164 struct fnhe_hash_bucket *hash;
165 int i;
166
167 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
168 if (!hash)
169 return;
170 for (i = 0; i < FNHE_HASH_SIZE; i++) {
171 struct fib_nh_exception *fnhe;
172
173 fnhe = rcu_dereference_protected(hash[i].chain, 1);
174 while (fnhe) {
175 struct fib_nh_exception *next;
176
177 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
178
179 rt_fibinfo_free(&fnhe->fnhe_rth_input);
180 rt_fibinfo_free(&fnhe->fnhe_rth_output);
181
182 kfree(fnhe);
183
184 fnhe = next;
185 }
186 }
187 kfree(hash);
188}
189
190static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
191{
192 int cpu;
193
194 if (!rtp)
195 return;
196
197 for_each_possible_cpu(cpu) {
198 struct rtable *rt;
199
200 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
201 if (rt) {
202 dst_dev_put(&rt->dst);
203 dst_release_immediate(&rt->dst);
204 }
205 }
206 free_percpu(rtp);
207}
208
209void fib_nh_common_release(struct fib_nh_common *nhc)
210{
211 if (nhc->nhc_dev)
212 dev_put(nhc->nhc_dev);
213
214 lwtstate_put(nhc->nhc_lwtstate);
215 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
216 rt_fibinfo_free(&nhc->nhc_rth_input);
217 free_nh_exceptions(nhc);
218}
219EXPORT_SYMBOL_GPL(fib_nh_common_release);
220
221void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
222{
223#ifdef CONFIG_IP_ROUTE_CLASSID
224 if (fib_nh->nh_tclassid)
225 net->ipv4.fib_num_tclassid_users--;
226#endif
227 fib_nh_common_release(&fib_nh->nh_common);
228}
229
230/* Release a nexthop info record */
231static void free_fib_info_rcu(struct rcu_head *head)
232{
233 struct fib_info *fi = container_of(head, struct fib_info, rcu);
234
235 if (fi->nh) {
236 nexthop_put(fi->nh);
237 } else {
238 change_nexthops(fi) {
239 fib_nh_release(fi->fib_net, nexthop_nh);
240 } endfor_nexthops(fi);
241 }
242
243 ip_fib_metrics_put(fi->fib_metrics);
244
245 kfree(fi);
246}
247
248void free_fib_info(struct fib_info *fi)
249{
250 if (fi->fib_dead == 0) {
251 pr_warn("Freeing alive fib_info %p\n", fi);
252 return;
253 }
254 fib_info_cnt--;
255
256 call_rcu(&fi->rcu, free_fib_info_rcu);
257}
258EXPORT_SYMBOL_GPL(free_fib_info);
259
260void fib_release_info(struct fib_info *fi)
261{
262 spin_lock_bh(&fib_info_lock);
263 if (fi && --fi->fib_treeref == 0) {
264 hlist_del(&fi->fib_hash);
265 if (fi->fib_prefsrc)
266 hlist_del(&fi->fib_lhash);
267 if (fi->nh) {
268 list_del(&fi->nh_list);
269 } else {
270 change_nexthops(fi) {
271 if (!nexthop_nh->fib_nh_dev)
272 continue;
273 hlist_del(&nexthop_nh->nh_hash);
274 } endfor_nexthops(fi)
275 }
276 fi->fib_dead = 1;
277 fib_info_put(fi);
278 }
279 spin_unlock_bh(&fib_info_lock);
280}
281
282static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
283{
284 const struct fib_nh *onh;
285
286 if (fi->nh || ofi->nh)
287 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
288
289 if (ofi->fib_nhs == 0)
290 return 0;
291
292 for_nexthops(fi) {
293 onh = fib_info_nh(ofi, nhsel);
294
295 if (nh->fib_nh_oif != onh->fib_nh_oif ||
296 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
297 nh->fib_nh_scope != onh->fib_nh_scope ||
298#ifdef CONFIG_IP_ROUTE_MULTIPATH
299 nh->fib_nh_weight != onh->fib_nh_weight ||
300#endif
301#ifdef CONFIG_IP_ROUTE_CLASSID
302 nh->nh_tclassid != onh->nh_tclassid ||
303#endif
304 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
305 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
306 return -1;
307
308 if (nh->fib_nh_gw_family == AF_INET &&
309 nh->fib_nh_gw4 != onh->fib_nh_gw4)
310 return -1;
311
312 if (nh->fib_nh_gw_family == AF_INET6 &&
313 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
314 return -1;
315 } endfor_nexthops(fi);
316 return 0;
317}
318
319static inline unsigned int fib_devindex_hashfn(unsigned int val)
320{
321 unsigned int mask = DEVINDEX_HASHSIZE - 1;
322
323 return (val ^
324 (val >> DEVINDEX_HASHBITS) ^
325 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
326}
327
328static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
329 u32 prefsrc, u32 priority)
330{
331 unsigned int val = init_val;
332
333 val ^= (protocol << 8) | scope;
334 val ^= prefsrc;
335 val ^= priority;
336
337 return val;
338}
339
340static unsigned int fib_info_hashfn_result(unsigned int val)
341{
342 unsigned int mask = (fib_info_hash_size - 1);
343
344 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
345}
346
347static inline unsigned int fib_info_hashfn(struct fib_info *fi)
348{
349 unsigned int val;
350
351 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
352 fi->fib_scope, (__force u32)fi->fib_prefsrc,
353 fi->fib_priority);
354
355 if (fi->nh) {
356 val ^= fib_devindex_hashfn(fi->nh->id);
357 } else {
358 for_nexthops(fi) {
359 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
360 } endfor_nexthops(fi)
361 }
362
363 return fib_info_hashfn_result(val);
364}
365
366/* no metrics, only nexthop id */
367static struct fib_info *fib_find_info_nh(struct net *net,
368 const struct fib_config *cfg)
369{
370 struct hlist_head *head;
371 struct fib_info *fi;
372 unsigned int hash;
373
374 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
375 cfg->fc_protocol, cfg->fc_scope,
376 (__force u32)cfg->fc_prefsrc,
377 cfg->fc_priority);
378 hash = fib_info_hashfn_result(hash);
379 head = &fib_info_hash[hash];
380
381 hlist_for_each_entry(fi, head, fib_hash) {
382 if (!net_eq(fi->fib_net, net))
383 continue;
384 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
385 continue;
386 if (cfg->fc_protocol == fi->fib_protocol &&
387 cfg->fc_scope == fi->fib_scope &&
388 cfg->fc_prefsrc == fi->fib_prefsrc &&
389 cfg->fc_priority == fi->fib_priority &&
390 cfg->fc_type == fi->fib_type &&
391 cfg->fc_table == fi->fib_tb_id &&
392 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
393 return fi;
394 }
395
396 return NULL;
397}
398
399static struct fib_info *fib_find_info(struct fib_info *nfi)
400{
401 struct hlist_head *head;
402 struct fib_info *fi;
403 unsigned int hash;
404
405 hash = fib_info_hashfn(nfi);
406 head = &fib_info_hash[hash];
407
408 hlist_for_each_entry(fi, head, fib_hash) {
409 if (!net_eq(fi->fib_net, nfi->fib_net))
410 continue;
411 if (fi->fib_nhs != nfi->fib_nhs)
412 continue;
413 if (nfi->fib_protocol == fi->fib_protocol &&
414 nfi->fib_scope == fi->fib_scope &&
415 nfi->fib_prefsrc == fi->fib_prefsrc &&
416 nfi->fib_priority == fi->fib_priority &&
417 nfi->fib_type == fi->fib_type &&
418 memcmp(nfi->fib_metrics, fi->fib_metrics,
419 sizeof(u32) * RTAX_MAX) == 0 &&
420 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
421 nh_comp(fi, nfi) == 0)
422 return fi;
423 }
424
425 return NULL;
426}
427
428/* Check, that the gateway is already configured.
429 * Used only by redirect accept routine.
430 */
431int ip_fib_check_default(__be32 gw, struct net_device *dev)
432{
433 struct hlist_head *head;
434 struct fib_nh *nh;
435 unsigned int hash;
436
437 spin_lock(&fib_info_lock);
438
439 hash = fib_devindex_hashfn(dev->ifindex);
440 head = &fib_info_devhash[hash];
441 hlist_for_each_entry(nh, head, nh_hash) {
442 if (nh->fib_nh_dev == dev &&
443 nh->fib_nh_gw4 == gw &&
444 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
445 spin_unlock(&fib_info_lock);
446 return 0;
447 }
448 }
449
450 spin_unlock(&fib_info_lock);
451
452 return -1;
453}
454
455size_t fib_nlmsg_size(struct fib_info *fi)
456{
457 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
458 + nla_total_size(4) /* RTA_TABLE */
459 + nla_total_size(4) /* RTA_DST */
460 + nla_total_size(4) /* RTA_PRIORITY */
461 + nla_total_size(4) /* RTA_PREFSRC */
462 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
463 unsigned int nhs = fib_info_num_path(fi);
464
465 /* space for nested metrics */
466 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
467
468 if (fi->nh)
469 payload += nla_total_size(4); /* RTA_NH_ID */
470
471 if (nhs) {
472 size_t nh_encapsize = 0;
473 /* Also handles the special case nhs == 1 */
474
475 /* each nexthop is packed in an attribute */
476 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
477 unsigned int i;
478
479 /* may contain flow and gateway attribute */
480 nhsize += 2 * nla_total_size(4);
481
482 /* grab encap info */
483 for (i = 0; i < fib_info_num_path(fi); i++) {
484 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
485
486 if (nhc->nhc_lwtstate) {
487 /* RTA_ENCAP_TYPE */
488 nh_encapsize += lwtunnel_get_encap_size(
489 nhc->nhc_lwtstate);
490 /* RTA_ENCAP */
491 nh_encapsize += nla_total_size(2);
492 }
493 }
494
495 /* all nexthops are packed in a nested attribute */
496 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
497
498 }
499
500 return payload;
501}
502
503void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
504 int dst_len, u32 tb_id, const struct nl_info *info,
505 unsigned int nlm_flags)
506{
507 struct fib_rt_info fri;
508 struct sk_buff *skb;
509 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
510 int err = -ENOBUFS;
511
512 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
513 if (!skb)
514 goto errout;
515
516 fri.fi = fa->fa_info;
517 fri.tb_id = tb_id;
518 fri.dst = key;
519 fri.dst_len = dst_len;
520 fri.tos = fa->fa_tos;
521 fri.type = fa->fa_type;
522 fri.offload = fa->offload;
523 fri.trap = fa->trap;
524 fri.offload_failed = fa->offload_failed;
525 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
526 if (err < 0) {
527 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
528 WARN_ON(err == -EMSGSIZE);
529 kfree_skb(skb);
530 goto errout;
531 }
532 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
533 info->nlh, GFP_KERNEL);
534 return;
535errout:
536 if (err < 0)
537 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
538}
539
540static int fib_detect_death(struct fib_info *fi, int order,
541 struct fib_info **last_resort, int *last_idx,
542 int dflt)
543{
544 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
545 struct neighbour *n;
546 int state = NUD_NONE;
547
548 if (likely(nhc->nhc_gw_family == AF_INET))
549 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
550 else if (nhc->nhc_gw_family == AF_INET6)
551 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
552 nhc->nhc_dev);
553 else
554 n = NULL;
555
556 if (n) {
557 state = n->nud_state;
558 neigh_release(n);
559 } else {
560 return 0;
561 }
562 if (state == NUD_REACHABLE)
563 return 0;
564 if ((state & NUD_VALID) && order != dflt)
565 return 0;
566 if ((state & NUD_VALID) ||
567 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
568 *last_resort = fi;
569 *last_idx = order;
570 }
571 return 1;
572}
573
574int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
575 struct nlattr *encap, u16 encap_type,
576 void *cfg, gfp_t gfp_flags,
577 struct netlink_ext_ack *extack)
578{
579 int err;
580
581 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
582 gfp_flags);
583 if (!nhc->nhc_pcpu_rth_output)
584 return -ENOMEM;
585
586 if (encap) {
587 struct lwtunnel_state *lwtstate;
588
589 if (encap_type == LWTUNNEL_ENCAP_NONE) {
590 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
591 err = -EINVAL;
592 goto lwt_failure;
593 }
594 err = lwtunnel_build_state(net, encap_type, encap,
595 nhc->nhc_family, cfg, &lwtstate,
596 extack);
597 if (err)
598 goto lwt_failure;
599
600 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
601 }
602
603 return 0;
604
605lwt_failure:
606 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
607 nhc->nhc_pcpu_rth_output = NULL;
608 return err;
609}
610EXPORT_SYMBOL_GPL(fib_nh_common_init);
611
612int fib_nh_init(struct net *net, struct fib_nh *nh,
613 struct fib_config *cfg, int nh_weight,
614 struct netlink_ext_ack *extack)
615{
616 int err;
617
618 nh->fib_nh_family = AF_INET;
619
620 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
621 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
622 if (err)
623 return err;
624
625 nh->fib_nh_oif = cfg->fc_oif;
626 nh->fib_nh_gw_family = cfg->fc_gw_family;
627 if (cfg->fc_gw_family == AF_INET)
628 nh->fib_nh_gw4 = cfg->fc_gw4;
629 else if (cfg->fc_gw_family == AF_INET6)
630 nh->fib_nh_gw6 = cfg->fc_gw6;
631
632 nh->fib_nh_flags = cfg->fc_flags;
633
634#ifdef CONFIG_IP_ROUTE_CLASSID
635 nh->nh_tclassid = cfg->fc_flow;
636 if (nh->nh_tclassid)
637 net->ipv4.fib_num_tclassid_users++;
638#endif
639#ifdef CONFIG_IP_ROUTE_MULTIPATH
640 nh->fib_nh_weight = nh_weight;
641#endif
642 return 0;
643}
644
645#ifdef CONFIG_IP_ROUTE_MULTIPATH
646
647static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
648 struct netlink_ext_ack *extack)
649{
650 int nhs = 0;
651
652 while (rtnh_ok(rtnh, remaining)) {
653 nhs++;
654 rtnh = rtnh_next(rtnh, &remaining);
655 }
656
657 /* leftover implies invalid nexthop configuration, discard it */
658 if (remaining > 0) {
659 NL_SET_ERR_MSG(extack,
660 "Invalid nexthop configuration - extra data after nexthops");
661 nhs = 0;
662 }
663
664 return nhs;
665}
666
667/* only called when fib_nh is integrated into fib_info */
668static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
669 int remaining, struct fib_config *cfg,
670 struct netlink_ext_ack *extack)
671{
672 struct net *net = fi->fib_net;
673 struct fib_config fib_cfg;
674 struct fib_nh *nh;
675 int ret;
676
677 change_nexthops(fi) {
678 int attrlen;
679
680 memset(&fib_cfg, 0, sizeof(fib_cfg));
681
682 if (!rtnh_ok(rtnh, remaining)) {
683 NL_SET_ERR_MSG(extack,
684 "Invalid nexthop configuration - extra data after nexthop");
685 return -EINVAL;
686 }
687
688 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
689 NL_SET_ERR_MSG(extack,
690 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
691 return -EINVAL;
692 }
693
694 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
695 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
696
697 attrlen = rtnh_attrlen(rtnh);
698 if (attrlen > 0) {
699 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
700
701 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
702 nlav = nla_find(attrs, attrlen, RTA_VIA);
703 if (nla && nlav) {
704 NL_SET_ERR_MSG(extack,
705 "Nexthop configuration can not contain both GATEWAY and VIA");
706 return -EINVAL;
707 }
708 if (nla) {
709 fib_cfg.fc_gw4 = nla_get_in_addr(nla);
710 if (fib_cfg.fc_gw4)
711 fib_cfg.fc_gw_family = AF_INET;
712 } else if (nlav) {
713 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
714 if (ret)
715 goto errout;
716 }
717
718 nla = nla_find(attrs, attrlen, RTA_FLOW);
719 if (nla)
720 fib_cfg.fc_flow = nla_get_u32(nla);
721
722 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
723 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
724 if (nla)
725 fib_cfg.fc_encap_type = nla_get_u16(nla);
726 }
727
728 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
729 rtnh->rtnh_hops + 1, extack);
730 if (ret)
731 goto errout;
732
733 rtnh = rtnh_next(rtnh, &remaining);
734 } endfor_nexthops(fi);
735
736 ret = -EINVAL;
737 nh = fib_info_nh(fi, 0);
738 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
739 NL_SET_ERR_MSG(extack,
740 "Nexthop device index does not match RTA_OIF");
741 goto errout;
742 }
743 if (cfg->fc_gw_family) {
744 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
745 (cfg->fc_gw_family == AF_INET &&
746 nh->fib_nh_gw4 != cfg->fc_gw4) ||
747 (cfg->fc_gw_family == AF_INET6 &&
748 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
749 NL_SET_ERR_MSG(extack,
750 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
751 goto errout;
752 }
753 }
754#ifdef CONFIG_IP_ROUTE_CLASSID
755 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
756 NL_SET_ERR_MSG(extack,
757 "Nexthop class id does not match RTA_FLOW");
758 goto errout;
759 }
760#endif
761 ret = 0;
762errout:
763 return ret;
764}
765
766/* only called when fib_nh is integrated into fib_info */
767static void fib_rebalance(struct fib_info *fi)
768{
769 int total;
770 int w;
771
772 if (fib_info_num_path(fi) < 2)
773 return;
774
775 total = 0;
776 for_nexthops(fi) {
777 if (nh->fib_nh_flags & RTNH_F_DEAD)
778 continue;
779
780 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
781 nh->fib_nh_flags & RTNH_F_LINKDOWN)
782 continue;
783
784 total += nh->fib_nh_weight;
785 } endfor_nexthops(fi);
786
787 w = 0;
788 change_nexthops(fi) {
789 int upper_bound;
790
791 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
792 upper_bound = -1;
793 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
794 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
795 upper_bound = -1;
796 } else {
797 w += nexthop_nh->fib_nh_weight;
798 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
799 total) - 1;
800 }
801
802 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
803 } endfor_nexthops(fi);
804}
805#else /* CONFIG_IP_ROUTE_MULTIPATH */
806
807static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
808 int remaining, struct fib_config *cfg,
809 struct netlink_ext_ack *extack)
810{
811 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
812
813 return -EINVAL;
814}
815
816#define fib_rebalance(fi) do { } while (0)
817
818#endif /* CONFIG_IP_ROUTE_MULTIPATH */
819
820static int fib_encap_match(struct net *net, u16 encap_type,
821 struct nlattr *encap,
822 const struct fib_nh *nh,
823 const struct fib_config *cfg,
824 struct netlink_ext_ack *extack)
825{
826 struct lwtunnel_state *lwtstate;
827 int ret, result = 0;
828
829 if (encap_type == LWTUNNEL_ENCAP_NONE)
830 return 0;
831
832 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
833 cfg, &lwtstate, extack);
834 if (!ret) {
835 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
836 lwtstate_free(lwtstate);
837 }
838
839 return result;
840}
841
842int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
843 struct netlink_ext_ack *extack)
844{
845#ifdef CONFIG_IP_ROUTE_MULTIPATH
846 struct rtnexthop *rtnh;
847 int remaining;
848#endif
849
850 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
851 return 1;
852
853 if (cfg->fc_nh_id) {
854 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
855 return 0;
856 return 1;
857 }
858
859 if (cfg->fc_oif || cfg->fc_gw_family) {
860 struct fib_nh *nh = fib_info_nh(fi, 0);
861
862 if (cfg->fc_encap) {
863 if (fib_encap_match(net, cfg->fc_encap_type,
864 cfg->fc_encap, nh, cfg, extack))
865 return 1;
866 }
867#ifdef CONFIG_IP_ROUTE_CLASSID
868 if (cfg->fc_flow &&
869 cfg->fc_flow != nh->nh_tclassid)
870 return 1;
871#endif
872 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
873 (cfg->fc_gw_family &&
874 cfg->fc_gw_family != nh->fib_nh_gw_family))
875 return 1;
876
877 if (cfg->fc_gw_family == AF_INET &&
878 cfg->fc_gw4 != nh->fib_nh_gw4)
879 return 1;
880
881 if (cfg->fc_gw_family == AF_INET6 &&
882 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
883 return 1;
884
885 return 0;
886 }
887
888#ifdef CONFIG_IP_ROUTE_MULTIPATH
889 if (!cfg->fc_mp)
890 return 0;
891
892 rtnh = cfg->fc_mp;
893 remaining = cfg->fc_mp_len;
894
895 for_nexthops(fi) {
896 int attrlen;
897
898 if (!rtnh_ok(rtnh, remaining))
899 return -EINVAL;
900
901 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
902 return 1;
903
904 attrlen = rtnh_attrlen(rtnh);
905 if (attrlen > 0) {
906 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
907
908 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
909 nlav = nla_find(attrs, attrlen, RTA_VIA);
910 if (nla && nlav) {
911 NL_SET_ERR_MSG(extack,
912 "Nexthop configuration can not contain both GATEWAY and VIA");
913 return -EINVAL;
914 }
915
916 if (nla) {
917 if (nh->fib_nh_gw_family != AF_INET ||
918 nla_get_in_addr(nla) != nh->fib_nh_gw4)
919 return 1;
920 } else if (nlav) {
921 struct fib_config cfg2;
922 int err;
923
924 err = fib_gw_from_via(&cfg2, nlav, extack);
925 if (err)
926 return err;
927
928 switch (nh->fib_nh_gw_family) {
929 case AF_INET:
930 if (cfg2.fc_gw_family != AF_INET ||
931 cfg2.fc_gw4 != nh->fib_nh_gw4)
932 return 1;
933 break;
934 case AF_INET6:
935 if (cfg2.fc_gw_family != AF_INET6 ||
936 ipv6_addr_cmp(&cfg2.fc_gw6,
937 &nh->fib_nh_gw6))
938 return 1;
939 break;
940 }
941 }
942
943#ifdef CONFIG_IP_ROUTE_CLASSID
944 nla = nla_find(attrs, attrlen, RTA_FLOW);
945 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
946 return 1;
947#endif
948 }
949
950 rtnh = rtnh_next(rtnh, &remaining);
951 } endfor_nexthops(fi);
952#endif
953 return 0;
954}
955
956bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
957{
958 struct nlattr *nla;
959 int remaining;
960
961 if (!cfg->fc_mx)
962 return true;
963
964 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
965 int type = nla_type(nla);
966 u32 fi_val, val;
967
968 if (!type)
969 continue;
970 if (type > RTAX_MAX)
971 return false;
972
973 if (type == RTAX_CC_ALGO) {
974 char tmp[TCP_CA_NAME_MAX];
975 bool ecn_ca = false;
976
977 nla_strscpy(tmp, nla, sizeof(tmp));
978 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
979 } else {
980 if (nla_len(nla) != sizeof(u32))
981 return false;
982 val = nla_get_u32(nla);
983 }
984
985 fi_val = fi->fib_metrics->metrics[type - 1];
986 if (type == RTAX_FEATURES)
987 fi_val &= ~DST_FEATURE_ECN_CA;
988
989 if (fi_val != val)
990 return false;
991 }
992
993 return true;
994}
995
996static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
997 u32 table, struct netlink_ext_ack *extack)
998{
999 struct fib6_config cfg = {
1000 .fc_table = table,
1001 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1002 .fc_ifindex = nh->fib_nh_oif,
1003 .fc_gateway = nh->fib_nh_gw6,
1004 };
1005 struct fib6_nh fib6_nh = {};
1006 int err;
1007
1008 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1009 if (!err) {
1010 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1011 dev_hold(nh->fib_nh_dev);
1012 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1013 nh->fib_nh_scope = RT_SCOPE_LINK;
1014
1015 ipv6_stub->fib6_nh_release(&fib6_nh);
1016 }
1017
1018 return err;
1019}
1020
1021/*
1022 * Picture
1023 * -------
1024 *
1025 * Semantics of nexthop is very messy by historical reasons.
1026 * We have to take into account, that:
1027 * a) gateway can be actually local interface address,
1028 * so that gatewayed route is direct.
1029 * b) gateway must be on-link address, possibly
1030 * described not by an ifaddr, but also by a direct route.
1031 * c) If both gateway and interface are specified, they should not
1032 * contradict.
1033 * d) If we use tunnel routes, gateway could be not on-link.
1034 *
1035 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1036 * results in pretty ugly and hairy code with obscure logic.
1037 *
1038 * I chose to generalized it instead, so that the size
1039 * of code does not increase practically, but it becomes
1040 * much more general.
1041 * Every prefix is assigned a "scope" value: "host" is local address,
1042 * "link" is direct route,
1043 * [ ... "site" ... "interior" ... ]
1044 * and "universe" is true gateway route with global meaning.
1045 *
1046 * Every prefix refers to a set of "nexthop"s (gw, oif),
1047 * where gw must have narrower scope. This recursion stops
1048 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1049 * which means that gw is forced to be on link.
1050 *
1051 * Code is still hairy, but now it is apparently logically
1052 * consistent and very flexible. F.e. as by-product it allows
1053 * to co-exists in peace independent exterior and interior
1054 * routing processes.
1055 *
1056 * Normally it looks as following.
1057 *
1058 * {universe prefix} -> (gw, oif) [scope link]
1059 * |
1060 * |-> {link prefix} -> (gw, oif) [scope local]
1061 * |
1062 * |-> {local prefix} (terminal node)
1063 */
1064static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1065 u8 scope, struct netlink_ext_ack *extack)
1066{
1067 struct net_device *dev;
1068 struct fib_result res;
1069 int err = 0;
1070
1071 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1072 unsigned int addr_type;
1073
1074 if (scope >= RT_SCOPE_LINK) {
1075 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1076 return -EINVAL;
1077 }
1078 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1079 if (!dev) {
1080 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1081 return -ENODEV;
1082 }
1083 if (!(dev->flags & IFF_UP)) {
1084 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1085 return -ENETDOWN;
1086 }
1087 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1088 if (addr_type != RTN_UNICAST) {
1089 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1090 return -EINVAL;
1091 }
1092 if (!netif_carrier_ok(dev))
1093 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1094 nh->fib_nh_dev = dev;
1095 dev_hold(dev);
1096 nh->fib_nh_scope = RT_SCOPE_LINK;
1097 return 0;
1098 }
1099 rcu_read_lock();
1100 {
1101 struct fib_table *tbl = NULL;
1102 struct flowi4 fl4 = {
1103 .daddr = nh->fib_nh_gw4,
1104 .flowi4_scope = scope + 1,
1105 .flowi4_oif = nh->fib_nh_oif,
1106 .flowi4_iif = LOOPBACK_IFINDEX,
1107 };
1108
1109 /* It is not necessary, but requires a bit of thinking */
1110 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1111 fl4.flowi4_scope = RT_SCOPE_LINK;
1112
1113 if (table && table != RT_TABLE_MAIN)
1114 tbl = fib_get_table(net, table);
1115
1116 if (tbl)
1117 err = fib_table_lookup(tbl, &fl4, &res,
1118 FIB_LOOKUP_IGNORE_LINKSTATE |
1119 FIB_LOOKUP_NOREF);
1120
1121 /* on error or if no table given do full lookup. This
1122 * is needed for example when nexthops are in the local
1123 * table rather than the given table
1124 */
1125 if (!tbl || err) {
1126 err = fib_lookup(net, &fl4, &res,
1127 FIB_LOOKUP_IGNORE_LINKSTATE);
1128 }
1129
1130 if (err) {
1131 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1132 goto out;
1133 }
1134 }
1135
1136 err = -EINVAL;
1137 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1138 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1139 goto out;
1140 }
1141 nh->fib_nh_scope = res.scope;
1142 nh->fib_nh_oif = FIB_RES_OIF(res);
1143 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1144 if (!dev) {
1145 NL_SET_ERR_MSG(extack,
1146 "No egress device for nexthop gateway");
1147 goto out;
1148 }
1149 dev_hold(dev);
1150 if (!netif_carrier_ok(dev))
1151 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1152 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1153out:
1154 rcu_read_unlock();
1155 return err;
1156}
1157
1158static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1159 struct netlink_ext_ack *extack)
1160{
1161 struct in_device *in_dev;
1162 int err;
1163
1164 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1165 NL_SET_ERR_MSG(extack,
1166 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1167 return -EINVAL;
1168 }
1169
1170 rcu_read_lock();
1171
1172 err = -ENODEV;
1173 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1174 if (!in_dev)
1175 goto out;
1176 err = -ENETDOWN;
1177 if (!(in_dev->dev->flags & IFF_UP)) {
1178 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1179 goto out;
1180 }
1181
1182 nh->fib_nh_dev = in_dev->dev;
1183 dev_hold(nh->fib_nh_dev);
1184 nh->fib_nh_scope = RT_SCOPE_HOST;
1185 if (!netif_carrier_ok(nh->fib_nh_dev))
1186 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1187 err = 0;
1188out:
1189 rcu_read_unlock();
1190 return err;
1191}
1192
1193int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1194 struct netlink_ext_ack *extack)
1195{
1196 int err;
1197
1198 if (nh->fib_nh_gw_family == AF_INET)
1199 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1200 else if (nh->fib_nh_gw_family == AF_INET6)
1201 err = fib_check_nh_v6_gw(net, nh, table, extack);
1202 else
1203 err = fib_check_nh_nongw(net, nh, extack);
1204
1205 return err;
1206}
1207
1208static inline unsigned int fib_laddr_hashfn(__be32 val)
1209{
1210 unsigned int mask = (fib_info_hash_size - 1);
1211
1212 return ((__force u32)val ^
1213 ((__force u32)val >> 7) ^
1214 ((__force u32)val >> 14)) & mask;
1215}
1216
1217static struct hlist_head *fib_info_hash_alloc(int bytes)
1218{
1219 if (bytes <= PAGE_SIZE)
1220 return kzalloc(bytes, GFP_KERNEL);
1221 else
1222 return (struct hlist_head *)
1223 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1224 get_order(bytes));
1225}
1226
1227static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1228{
1229 if (!hash)
1230 return;
1231
1232 if (bytes <= PAGE_SIZE)
1233 kfree(hash);
1234 else
1235 free_pages((unsigned long) hash, get_order(bytes));
1236}
1237
1238static void fib_info_hash_move(struct hlist_head *new_info_hash,
1239 struct hlist_head *new_laddrhash,
1240 unsigned int new_size)
1241{
1242 struct hlist_head *old_info_hash, *old_laddrhash;
1243 unsigned int old_size = fib_info_hash_size;
1244 unsigned int i, bytes;
1245
1246 spin_lock_bh(&fib_info_lock);
1247 old_info_hash = fib_info_hash;
1248 old_laddrhash = fib_info_laddrhash;
1249 fib_info_hash_size = new_size;
1250
1251 for (i = 0; i < old_size; i++) {
1252 struct hlist_head *head = &fib_info_hash[i];
1253 struct hlist_node *n;
1254 struct fib_info *fi;
1255
1256 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1257 struct hlist_head *dest;
1258 unsigned int new_hash;
1259
1260 new_hash = fib_info_hashfn(fi);
1261 dest = &new_info_hash[new_hash];
1262 hlist_add_head(&fi->fib_hash, dest);
1263 }
1264 }
1265 fib_info_hash = new_info_hash;
1266
1267 for (i = 0; i < old_size; i++) {
1268 struct hlist_head *lhead = &fib_info_laddrhash[i];
1269 struct hlist_node *n;
1270 struct fib_info *fi;
1271
1272 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1273 struct hlist_head *ldest;
1274 unsigned int new_hash;
1275
1276 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1277 ldest = &new_laddrhash[new_hash];
1278 hlist_add_head(&fi->fib_lhash, ldest);
1279 }
1280 }
1281 fib_info_laddrhash = new_laddrhash;
1282
1283 spin_unlock_bh(&fib_info_lock);
1284
1285 bytes = old_size * sizeof(struct hlist_head *);
1286 fib_info_hash_free(old_info_hash, bytes);
1287 fib_info_hash_free(old_laddrhash, bytes);
1288}
1289
1290__be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1291 unsigned char scope)
1292{
1293 struct fib_nh *nh;
1294
1295 if (nhc->nhc_family != AF_INET)
1296 return inet_select_addr(nhc->nhc_dev, 0, scope);
1297
1298 nh = container_of(nhc, struct fib_nh, nh_common);
1299 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1300 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1301
1302 return nh->nh_saddr;
1303}
1304
1305__be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1306{
1307 struct fib_nh_common *nhc = res->nhc;
1308
1309 if (res->fi->fib_prefsrc)
1310 return res->fi->fib_prefsrc;
1311
1312 if (nhc->nhc_family == AF_INET) {
1313 struct fib_nh *nh;
1314
1315 nh = container_of(nhc, struct fib_nh, nh_common);
1316 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1317 return nh->nh_saddr;
1318 }
1319
1320 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1321}
1322
1323static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1324{
1325 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1326 fib_prefsrc != cfg->fc_dst) {
1327 u32 tb_id = cfg->fc_table;
1328 int rc;
1329
1330 if (tb_id == RT_TABLE_MAIN)
1331 tb_id = RT_TABLE_LOCAL;
1332
1333 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1334 fib_prefsrc, tb_id);
1335
1336 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1337 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1338 fib_prefsrc, RT_TABLE_LOCAL);
1339 }
1340
1341 if (rc != RTN_LOCAL)
1342 return false;
1343 }
1344 return true;
1345}
1346
1347struct fib_info *fib_create_info(struct fib_config *cfg,
1348 struct netlink_ext_ack *extack)
1349{
1350 int err;
1351 struct fib_info *fi = NULL;
1352 struct nexthop *nh = NULL;
1353 struct fib_info *ofi;
1354 int nhs = 1;
1355 struct net *net = cfg->fc_nlinfo.nl_net;
1356
1357 if (cfg->fc_type > RTN_MAX)
1358 goto err_inval;
1359
1360 /* Fast check to catch the most weird cases */
1361 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1362 NL_SET_ERR_MSG(extack, "Invalid scope");
1363 goto err_inval;
1364 }
1365
1366 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1367 NL_SET_ERR_MSG(extack,
1368 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1369 goto err_inval;
1370 }
1371
1372 if (cfg->fc_nh_id) {
1373 if (!cfg->fc_mx) {
1374 fi = fib_find_info_nh(net, cfg);
1375 if (fi) {
1376 fi->fib_treeref++;
1377 return fi;
1378 }
1379 }
1380
1381 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1382 if (!nh) {
1383 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1384 goto err_inval;
1385 }
1386 nhs = 0;
1387 }
1388
1389#ifdef CONFIG_IP_ROUTE_MULTIPATH
1390 if (cfg->fc_mp) {
1391 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1392 if (nhs == 0)
1393 goto err_inval;
1394 }
1395#endif
1396
1397 err = -ENOBUFS;
1398 if (fib_info_cnt >= fib_info_hash_size) {
1399 unsigned int new_size = fib_info_hash_size << 1;
1400 struct hlist_head *new_info_hash;
1401 struct hlist_head *new_laddrhash;
1402 unsigned int bytes;
1403
1404 if (!new_size)
1405 new_size = 16;
1406 bytes = new_size * sizeof(struct hlist_head *);
1407 new_info_hash = fib_info_hash_alloc(bytes);
1408 new_laddrhash = fib_info_hash_alloc(bytes);
1409 if (!new_info_hash || !new_laddrhash) {
1410 fib_info_hash_free(new_info_hash, bytes);
1411 fib_info_hash_free(new_laddrhash, bytes);
1412 } else
1413 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1414
1415 if (!fib_info_hash_size)
1416 goto failure;
1417 }
1418
1419 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1420 if (!fi)
1421 goto failure;
1422 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1423 cfg->fc_mx_len, extack);
1424 if (IS_ERR(fi->fib_metrics)) {
1425 err = PTR_ERR(fi->fib_metrics);
1426 kfree(fi);
1427 return ERR_PTR(err);
1428 }
1429
1430 fib_info_cnt++;
1431 fi->fib_net = net;
1432 fi->fib_protocol = cfg->fc_protocol;
1433 fi->fib_scope = cfg->fc_scope;
1434 fi->fib_flags = cfg->fc_flags;
1435 fi->fib_priority = cfg->fc_priority;
1436 fi->fib_prefsrc = cfg->fc_prefsrc;
1437 fi->fib_type = cfg->fc_type;
1438 fi->fib_tb_id = cfg->fc_table;
1439
1440 fi->fib_nhs = nhs;
1441 if (nh) {
1442 if (!nexthop_get(nh)) {
1443 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1444 err = -EINVAL;
1445 } else {
1446 err = 0;
1447 fi->nh = nh;
1448 }
1449 } else {
1450 change_nexthops(fi) {
1451 nexthop_nh->nh_parent = fi;
1452 } endfor_nexthops(fi)
1453
1454 if (cfg->fc_mp)
1455 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1456 extack);
1457 else
1458 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1459 }
1460
1461 if (err != 0)
1462 goto failure;
1463
1464 if (fib_props[cfg->fc_type].error) {
1465 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1466 NL_SET_ERR_MSG(extack,
1467 "Gateway, device and multipath can not be specified for this route type");
1468 goto err_inval;
1469 }
1470 goto link_it;
1471 } else {
1472 switch (cfg->fc_type) {
1473 case RTN_UNICAST:
1474 case RTN_LOCAL:
1475 case RTN_BROADCAST:
1476 case RTN_ANYCAST:
1477 case RTN_MULTICAST:
1478 break;
1479 default:
1480 NL_SET_ERR_MSG(extack, "Invalid route type");
1481 goto err_inval;
1482 }
1483 }
1484
1485 if (cfg->fc_scope > RT_SCOPE_HOST) {
1486 NL_SET_ERR_MSG(extack, "Invalid scope");
1487 goto err_inval;
1488 }
1489
1490 if (fi->nh) {
1491 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1492 if (err)
1493 goto failure;
1494 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1495 struct fib_nh *nh = fi->fib_nh;
1496
1497 /* Local address is added. */
1498 if (nhs != 1) {
1499 NL_SET_ERR_MSG(extack,
1500 "Route with host scope can not have multiple nexthops");
1501 goto err_inval;
1502 }
1503 if (nh->fib_nh_gw_family) {
1504 NL_SET_ERR_MSG(extack,
1505 "Route with host scope can not have a gateway");
1506 goto err_inval;
1507 }
1508 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1509 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1510 err = -ENODEV;
1511 if (!nh->fib_nh_dev)
1512 goto failure;
1513 } else {
1514 int linkdown = 0;
1515
1516 change_nexthops(fi) {
1517 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1518 cfg->fc_table, cfg->fc_scope,
1519 extack);
1520 if (err != 0)
1521 goto failure;
1522 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1523 linkdown++;
1524 } endfor_nexthops(fi)
1525 if (linkdown == fi->fib_nhs)
1526 fi->fib_flags |= RTNH_F_LINKDOWN;
1527 }
1528
1529 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1530 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1531 goto err_inval;
1532 }
1533
1534 if (!fi->nh) {
1535 change_nexthops(fi) {
1536 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1537 fi->fib_scope);
1538 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1539 fi->fib_nh_is_v6 = true;
1540 } endfor_nexthops(fi)
1541
1542 fib_rebalance(fi);
1543 }
1544
1545link_it:
1546 ofi = fib_find_info(fi);
1547 if (ofi) {
1548 fi->fib_dead = 1;
1549 free_fib_info(fi);
1550 ofi->fib_treeref++;
1551 return ofi;
1552 }
1553
1554 fi->fib_treeref++;
1555 refcount_set(&fi->fib_clntref, 1);
1556 spin_lock_bh(&fib_info_lock);
1557 hlist_add_head(&fi->fib_hash,
1558 &fib_info_hash[fib_info_hashfn(fi)]);
1559 if (fi->fib_prefsrc) {
1560 struct hlist_head *head;
1561
1562 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1563 hlist_add_head(&fi->fib_lhash, head);
1564 }
1565 if (fi->nh) {
1566 list_add(&fi->nh_list, &nh->fi_list);
1567 } else {
1568 change_nexthops(fi) {
1569 struct hlist_head *head;
1570 unsigned int hash;
1571
1572 if (!nexthop_nh->fib_nh_dev)
1573 continue;
1574 hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
1575 head = &fib_info_devhash[hash];
1576 hlist_add_head(&nexthop_nh->nh_hash, head);
1577 } endfor_nexthops(fi)
1578 }
1579 spin_unlock_bh(&fib_info_lock);
1580 return fi;
1581
1582err_inval:
1583 err = -EINVAL;
1584
1585failure:
1586 if (fi) {
1587 fi->fib_dead = 1;
1588 free_fib_info(fi);
1589 }
1590
1591 return ERR_PTR(err);
1592}
1593
1594int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1595 u8 rt_family, unsigned char *flags, bool skip_oif)
1596{
1597 if (nhc->nhc_flags & RTNH_F_DEAD)
1598 *flags |= RTNH_F_DEAD;
1599
1600 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1601 *flags |= RTNH_F_LINKDOWN;
1602
1603 rcu_read_lock();
1604 switch (nhc->nhc_family) {
1605 case AF_INET:
1606 if (ip_ignore_linkdown(nhc->nhc_dev))
1607 *flags |= RTNH_F_DEAD;
1608 break;
1609 case AF_INET6:
1610 if (ip6_ignore_linkdown(nhc->nhc_dev))
1611 *flags |= RTNH_F_DEAD;
1612 break;
1613 }
1614 rcu_read_unlock();
1615 }
1616
1617 switch (nhc->nhc_gw_family) {
1618 case AF_INET:
1619 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1620 goto nla_put_failure;
1621 break;
1622 case AF_INET6:
1623 /* if gateway family does not match nexthop family
1624 * gateway is encoded as RTA_VIA
1625 */
1626 if (rt_family != nhc->nhc_gw_family) {
1627 int alen = sizeof(struct in6_addr);
1628 struct nlattr *nla;
1629 struct rtvia *via;
1630
1631 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1632 if (!nla)
1633 goto nla_put_failure;
1634
1635 via = nla_data(nla);
1636 via->rtvia_family = AF_INET6;
1637 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1638 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1639 &nhc->nhc_gw.ipv6) < 0) {
1640 goto nla_put_failure;
1641 }
1642 break;
1643 }
1644
1645 *flags |= (nhc->nhc_flags &
1646 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1647
1648 if (!skip_oif && nhc->nhc_dev &&
1649 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1650 goto nla_put_failure;
1651
1652 if (nhc->nhc_lwtstate &&
1653 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1654 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1655 goto nla_put_failure;
1656
1657 return 0;
1658
1659nla_put_failure:
1660 return -EMSGSIZE;
1661}
1662EXPORT_SYMBOL_GPL(fib_nexthop_info);
1663
1664#if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1665int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1666 int nh_weight, u8 rt_family, u32 nh_tclassid)
1667{
1668 const struct net_device *dev = nhc->nhc_dev;
1669 struct rtnexthop *rtnh;
1670 unsigned char flags = 0;
1671
1672 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1673 if (!rtnh)
1674 goto nla_put_failure;
1675
1676 rtnh->rtnh_hops = nh_weight - 1;
1677 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1678
1679 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1680 goto nla_put_failure;
1681
1682 rtnh->rtnh_flags = flags;
1683
1684 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1685 goto nla_put_failure;
1686
1687 /* length of rtnetlink header + attributes */
1688 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1689
1690 return 0;
1691
1692nla_put_failure:
1693 return -EMSGSIZE;
1694}
1695EXPORT_SYMBOL_GPL(fib_add_nexthop);
1696#endif
1697
1698#ifdef CONFIG_IP_ROUTE_MULTIPATH
1699static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1700{
1701 struct nlattr *mp;
1702
1703 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1704 if (!mp)
1705 goto nla_put_failure;
1706
1707 if (unlikely(fi->nh)) {
1708 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1709 goto nla_put_failure;
1710 goto mp_end;
1711 }
1712
1713 for_nexthops(fi) {
1714 u32 nh_tclassid = 0;
1715#ifdef CONFIG_IP_ROUTE_CLASSID
1716 nh_tclassid = nh->nh_tclassid;
1717#endif
1718 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1719 AF_INET, nh_tclassid) < 0)
1720 goto nla_put_failure;
1721 } endfor_nexthops(fi);
1722
1723mp_end:
1724 nla_nest_end(skb, mp);
1725
1726 return 0;
1727
1728nla_put_failure:
1729 return -EMSGSIZE;
1730}
1731#else
1732static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1733{
1734 return 0;
1735}
1736#endif
1737
1738int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1739 const struct fib_rt_info *fri, unsigned int flags)
1740{
1741 unsigned int nhs = fib_info_num_path(fri->fi);
1742 struct fib_info *fi = fri->fi;
1743 u32 tb_id = fri->tb_id;
1744 struct nlmsghdr *nlh;
1745 struct rtmsg *rtm;
1746
1747 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1748 if (!nlh)
1749 return -EMSGSIZE;
1750
1751 rtm = nlmsg_data(nlh);
1752 rtm->rtm_family = AF_INET;
1753 rtm->rtm_dst_len = fri->dst_len;
1754 rtm->rtm_src_len = 0;
1755 rtm->rtm_tos = fri->tos;
1756 if (tb_id < 256)
1757 rtm->rtm_table = tb_id;
1758 else
1759 rtm->rtm_table = RT_TABLE_COMPAT;
1760 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1761 goto nla_put_failure;
1762 rtm->rtm_type = fri->type;
1763 rtm->rtm_flags = fi->fib_flags;
1764 rtm->rtm_scope = fi->fib_scope;
1765 rtm->rtm_protocol = fi->fib_protocol;
1766
1767 if (rtm->rtm_dst_len &&
1768 nla_put_in_addr(skb, RTA_DST, fri->dst))
1769 goto nla_put_failure;
1770 if (fi->fib_priority &&
1771 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1772 goto nla_put_failure;
1773 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1774 goto nla_put_failure;
1775
1776 if (fi->fib_prefsrc &&
1777 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1778 goto nla_put_failure;
1779
1780 if (fi->nh) {
1781 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1782 goto nla_put_failure;
1783 if (nexthop_is_blackhole(fi->nh))
1784 rtm->rtm_type = RTN_BLACKHOLE;
1785 if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode)
1786 goto offload;
1787 }
1788
1789 if (nhs == 1) {
1790 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1791 unsigned char flags = 0;
1792
1793 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1794 goto nla_put_failure;
1795
1796 rtm->rtm_flags = flags;
1797#ifdef CONFIG_IP_ROUTE_CLASSID
1798 if (nhc->nhc_family == AF_INET) {
1799 struct fib_nh *nh;
1800
1801 nh = container_of(nhc, struct fib_nh, nh_common);
1802 if (nh->nh_tclassid &&
1803 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1804 goto nla_put_failure;
1805 }
1806#endif
1807 } else {
1808 if (fib_add_multipath(skb, fi) < 0)
1809 goto nla_put_failure;
1810 }
1811
1812offload:
1813 if (fri->offload)
1814 rtm->rtm_flags |= RTM_F_OFFLOAD;
1815 if (fri->trap)
1816 rtm->rtm_flags |= RTM_F_TRAP;
1817 if (fri->offload_failed)
1818 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1819
1820 nlmsg_end(skb, nlh);
1821 return 0;
1822
1823nla_put_failure:
1824 nlmsg_cancel(skb, nlh);
1825 return -EMSGSIZE;
1826}
1827
1828/*
1829 * Update FIB if:
1830 * - local address disappeared -> we must delete all the entries
1831 * referring to it.
1832 * - device went down -> we must shutdown all nexthops going via it.
1833 */
1834int fib_sync_down_addr(struct net_device *dev, __be32 local)
1835{
1836 int ret = 0;
1837 unsigned int hash = fib_laddr_hashfn(local);
1838 struct hlist_head *head = &fib_info_laddrhash[hash];
1839 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1840 struct net *net = dev_net(dev);
1841 struct fib_info *fi;
1842
1843 if (!fib_info_laddrhash || local == 0)
1844 return 0;
1845
1846 hlist_for_each_entry(fi, head, fib_lhash) {
1847 if (!net_eq(fi->fib_net, net) ||
1848 fi->fib_tb_id != tb_id)
1849 continue;
1850 if (fi->fib_prefsrc == local) {
1851 fi->fib_flags |= RTNH_F_DEAD;
1852 ret++;
1853 }
1854 }
1855 return ret;
1856}
1857
1858static int call_fib_nh_notifiers(struct fib_nh *nh,
1859 enum fib_event_type event_type)
1860{
1861 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1862 struct fib_nh_notifier_info info = {
1863 .fib_nh = nh,
1864 };
1865
1866 switch (event_type) {
1867 case FIB_EVENT_NH_ADD:
1868 if (nh->fib_nh_flags & RTNH_F_DEAD)
1869 break;
1870 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1871 break;
1872 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1873 &info.info);
1874 case FIB_EVENT_NH_DEL:
1875 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1876 (nh->fib_nh_flags & RTNH_F_DEAD))
1877 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1878 event_type, &info.info);
1879 break;
1880 default:
1881 break;
1882 }
1883
1884 return NOTIFY_DONE;
1885}
1886
1887/* Update the PMTU of exceptions when:
1888 * - the new MTU of the first hop becomes smaller than the PMTU
1889 * - the old MTU was the same as the PMTU, and it limited discovery of
1890 * larger MTUs on the path. With that limit raised, we can now
1891 * discover larger MTUs
1892 * A special case is locked exceptions, for which the PMTU is smaller
1893 * than the minimal accepted PMTU:
1894 * - if the new MTU is greater than the PMTU, don't make any change
1895 * - otherwise, unlock and set PMTU
1896 */
1897void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1898{
1899 struct fnhe_hash_bucket *bucket;
1900 int i;
1901
1902 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1903 if (!bucket)
1904 return;
1905
1906 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1907 struct fib_nh_exception *fnhe;
1908
1909 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1910 fnhe;
1911 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1912 if (fnhe->fnhe_mtu_locked) {
1913 if (new <= fnhe->fnhe_pmtu) {
1914 fnhe->fnhe_pmtu = new;
1915 fnhe->fnhe_mtu_locked = false;
1916 }
1917 } else if (new < fnhe->fnhe_pmtu ||
1918 orig == fnhe->fnhe_pmtu) {
1919 fnhe->fnhe_pmtu = new;
1920 }
1921 }
1922 }
1923}
1924
1925void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1926{
1927 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1928 struct hlist_head *head = &fib_info_devhash[hash];
1929 struct fib_nh *nh;
1930
1931 hlist_for_each_entry(nh, head, nh_hash) {
1932 if (nh->fib_nh_dev == dev)
1933 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1934 }
1935}
1936
1937/* Event force Flags Description
1938 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1939 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1940 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1941 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1942 *
1943 * only used when fib_nh is built into fib_info
1944 */
1945int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1946{
1947 int ret = 0;
1948 int scope = RT_SCOPE_NOWHERE;
1949 struct fib_info *prev_fi = NULL;
1950 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1951 struct hlist_head *head = &fib_info_devhash[hash];
1952 struct fib_nh *nh;
1953
1954 if (force)
1955 scope = -1;
1956
1957 hlist_for_each_entry(nh, head, nh_hash) {
1958 struct fib_info *fi = nh->nh_parent;
1959 int dead;
1960
1961 BUG_ON(!fi->fib_nhs);
1962 if (nh->fib_nh_dev != dev || fi == prev_fi)
1963 continue;
1964 prev_fi = fi;
1965 dead = 0;
1966 change_nexthops(fi) {
1967 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1968 dead++;
1969 else if (nexthop_nh->fib_nh_dev == dev &&
1970 nexthop_nh->fib_nh_scope != scope) {
1971 switch (event) {
1972 case NETDEV_DOWN:
1973 case NETDEV_UNREGISTER:
1974 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1975 fallthrough;
1976 case NETDEV_CHANGE:
1977 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1978 break;
1979 }
1980 call_fib_nh_notifiers(nexthop_nh,
1981 FIB_EVENT_NH_DEL);
1982 dead++;
1983 }
1984#ifdef CONFIG_IP_ROUTE_MULTIPATH
1985 if (event == NETDEV_UNREGISTER &&
1986 nexthop_nh->fib_nh_dev == dev) {
1987 dead = fi->fib_nhs;
1988 break;
1989 }
1990#endif
1991 } endfor_nexthops(fi)
1992 if (dead == fi->fib_nhs) {
1993 switch (event) {
1994 case NETDEV_DOWN:
1995 case NETDEV_UNREGISTER:
1996 fi->fib_flags |= RTNH_F_DEAD;
1997 fallthrough;
1998 case NETDEV_CHANGE:
1999 fi->fib_flags |= RTNH_F_LINKDOWN;
2000 break;
2001 }
2002 ret++;
2003 }
2004
2005 fib_rebalance(fi);
2006 }
2007
2008 return ret;
2009}
2010
2011/* Must be invoked inside of an RCU protected region. */
2012static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2013{
2014 struct fib_info *fi = NULL, *last_resort = NULL;
2015 struct hlist_head *fa_head = res->fa_head;
2016 struct fib_table *tb = res->table;
2017 u8 slen = 32 - res->prefixlen;
2018 int order = -1, last_idx = -1;
2019 struct fib_alias *fa, *fa1 = NULL;
2020 u32 last_prio = res->fi->fib_priority;
2021 u8 last_tos = 0;
2022
2023 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2024 struct fib_info *next_fi = fa->fa_info;
2025 struct fib_nh_common *nhc;
2026
2027 if (fa->fa_slen != slen)
2028 continue;
2029 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2030 continue;
2031 if (fa->tb_id != tb->tb_id)
2032 continue;
2033 if (next_fi->fib_priority > last_prio &&
2034 fa->fa_tos == last_tos) {
2035 if (last_tos)
2036 continue;
2037 break;
2038 }
2039 if (next_fi->fib_flags & RTNH_F_DEAD)
2040 continue;
2041 last_tos = fa->fa_tos;
2042 last_prio = next_fi->fib_priority;
2043
2044 if (next_fi->fib_scope != res->scope ||
2045 fa->fa_type != RTN_UNICAST)
2046 continue;
2047
2048 nhc = fib_info_nhc(next_fi, 0);
2049 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2050 continue;
2051
2052 fib_alias_accessed(fa);
2053
2054 if (!fi) {
2055 if (next_fi != res->fi)
2056 break;
2057 fa1 = fa;
2058 } else if (!fib_detect_death(fi, order, &last_resort,
2059 &last_idx, fa1->fa_default)) {
2060 fib_result_assign(res, fi);
2061 fa1->fa_default = order;
2062 goto out;
2063 }
2064 fi = next_fi;
2065 order++;
2066 }
2067
2068 if (order <= 0 || !fi) {
2069 if (fa1)
2070 fa1->fa_default = -1;
2071 goto out;
2072 }
2073
2074 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2075 fa1->fa_default)) {
2076 fib_result_assign(res, fi);
2077 fa1->fa_default = order;
2078 goto out;
2079 }
2080
2081 if (last_idx >= 0)
2082 fib_result_assign(res, last_resort);
2083 fa1->fa_default = last_idx;
2084out:
2085 return;
2086}
2087
2088/*
2089 * Dead device goes up. We wake up dead nexthops.
2090 * It takes sense only on multipath routes.
2091 *
2092 * only used when fib_nh is built into fib_info
2093 */
2094int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2095{
2096 struct fib_info *prev_fi;
2097 unsigned int hash;
2098 struct hlist_head *head;
2099 struct fib_nh *nh;
2100 int ret;
2101
2102 if (!(dev->flags & IFF_UP))
2103 return 0;
2104
2105 if (nh_flags & RTNH_F_DEAD) {
2106 unsigned int flags = dev_get_flags(dev);
2107
2108 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2109 nh_flags |= RTNH_F_LINKDOWN;
2110 }
2111
2112 prev_fi = NULL;
2113 hash = fib_devindex_hashfn(dev->ifindex);
2114 head = &fib_info_devhash[hash];
2115 ret = 0;
2116
2117 hlist_for_each_entry(nh, head, nh_hash) {
2118 struct fib_info *fi = nh->nh_parent;
2119 int alive;
2120
2121 BUG_ON(!fi->fib_nhs);
2122 if (nh->fib_nh_dev != dev || fi == prev_fi)
2123 continue;
2124
2125 prev_fi = fi;
2126 alive = 0;
2127 change_nexthops(fi) {
2128 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2129 alive++;
2130 continue;
2131 }
2132 if (!nexthop_nh->fib_nh_dev ||
2133 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2134 continue;
2135 if (nexthop_nh->fib_nh_dev != dev ||
2136 !__in_dev_get_rtnl(dev))
2137 continue;
2138 alive++;
2139 nexthop_nh->fib_nh_flags &= ~nh_flags;
2140 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2141 } endfor_nexthops(fi)
2142
2143 if (alive > 0) {
2144 fi->fib_flags &= ~nh_flags;
2145 ret++;
2146 }
2147
2148 fib_rebalance(fi);
2149 }
2150
2151 return ret;
2152}
2153
2154#ifdef CONFIG_IP_ROUTE_MULTIPATH
2155static bool fib_good_nh(const struct fib_nh *nh)
2156{
2157 int state = NUD_REACHABLE;
2158
2159 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2160 struct neighbour *n;
2161
2162 rcu_read_lock_bh();
2163
2164 if (likely(nh->fib_nh_gw_family == AF_INET))
2165 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2166 (__force u32)nh->fib_nh_gw4);
2167 else if (nh->fib_nh_gw_family == AF_INET6)
2168 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2169 &nh->fib_nh_gw6);
2170 else
2171 n = NULL;
2172 if (n)
2173 state = n->nud_state;
2174
2175 rcu_read_unlock_bh();
2176 }
2177
2178 return !!(state & NUD_VALID);
2179}
2180
2181void fib_select_multipath(struct fib_result *res, int hash)
2182{
2183 struct fib_info *fi = res->fi;
2184 struct net *net = fi->fib_net;
2185 bool first = false;
2186
2187 if (unlikely(res->fi->nh)) {
2188 nexthop_path_fib_result(res, hash);
2189 return;
2190 }
2191
2192 change_nexthops(fi) {
2193 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2194 if (!fib_good_nh(nexthop_nh))
2195 continue;
2196 if (!first) {
2197 res->nh_sel = nhsel;
2198 res->nhc = &nexthop_nh->nh_common;
2199 first = true;
2200 }
2201 }
2202
2203 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2204 continue;
2205
2206 res->nh_sel = nhsel;
2207 res->nhc = &nexthop_nh->nh_common;
2208 return;
2209 } endfor_nexthops(fi);
2210}
2211#endif
2212
2213void fib_select_path(struct net *net, struct fib_result *res,
2214 struct flowi4 *fl4, const struct sk_buff *skb)
2215{
2216 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2217 goto check_saddr;
2218
2219#ifdef CONFIG_IP_ROUTE_MULTIPATH
2220 if (fib_info_num_path(res->fi) > 1) {
2221 int h = fib_multipath_hash(net, fl4, skb, NULL);
2222
2223 fib_select_multipath(res, h);
2224 }
2225 else
2226#endif
2227 if (!res->prefixlen &&
2228 res->table->tb_num_default > 1 &&
2229 res->type == RTN_UNICAST)
2230 fib_select_default(fl4, res);
2231
2232check_saddr:
2233 if (!fl4->saddr)
2234 fl4->saddr = fib_result_prefsrc(net, res);
2235}