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1/*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * IPv4 Forwarding Information Base: semantics.
7 *
8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16#include <asm/uaccess.h>
17#include <linux/bitops.h>
18#include <linux/types.h>
19#include <linux/kernel.h>
20#include <linux/jiffies.h>
21#include <linux/mm.h>
22#include <linux/string.h>
23#include <linux/socket.h>
24#include <linux/sockios.h>
25#include <linux/errno.h>
26#include <linux/in.h>
27#include <linux/inet.h>
28#include <linux/inetdevice.h>
29#include <linux/netdevice.h>
30#include <linux/if_arp.h>
31#include <linux/proc_fs.h>
32#include <linux/skbuff.h>
33#include <linux/init.h>
34#include <linux/slab.h>
35
36#include <net/arp.h>
37#include <net/ip.h>
38#include <net/protocol.h>
39#include <net/route.h>
40#include <net/tcp.h>
41#include <net/sock.h>
42#include <net/ip_fib.h>
43#include <net/netlink.h>
44#include <net/nexthop.h>
45#include <net/lwtunnel.h>
46
47#include "fib_lookup.h"
48
49static DEFINE_SPINLOCK(fib_info_lock);
50static struct hlist_head *fib_info_hash;
51static struct hlist_head *fib_info_laddrhash;
52static unsigned int fib_info_hash_size;
53static unsigned int fib_info_cnt;
54
55#define DEVINDEX_HASHBITS 8
56#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59#ifdef CONFIG_IP_ROUTE_MULTIPATH
60u32 fib_multipath_secret __read_mostly;
61
62#define for_nexthops(fi) { \
63 int nhsel; const struct fib_nh *nh; \
64 for (nhsel = 0, nh = (fi)->fib_nh; \
65 nhsel < (fi)->fib_nhs; \
66 nh++, nhsel++)
67
68#define change_nexthops(fi) { \
69 int nhsel; struct fib_nh *nexthop_nh; \
70 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
71 nhsel < (fi)->fib_nhs; \
72 nexthop_nh++, nhsel++)
73
74#else /* CONFIG_IP_ROUTE_MULTIPATH */
75
76/* Hope, that gcc will optimize it to get rid of dummy loop */
77
78#define for_nexthops(fi) { \
79 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
80 for (nhsel = 0; nhsel < 1; nhsel++)
81
82#define change_nexthops(fi) { \
83 int nhsel; \
84 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87#endif /* CONFIG_IP_ROUTE_MULTIPATH */
88
89#define endfor_nexthops(fi) }
90
91
92const struct fib_prop fib_props[RTN_MAX + 1] = {
93 [RTN_UNSPEC] = {
94 .error = 0,
95 .scope = RT_SCOPE_NOWHERE,
96 },
97 [RTN_UNICAST] = {
98 .error = 0,
99 .scope = RT_SCOPE_UNIVERSE,
100 },
101 [RTN_LOCAL] = {
102 .error = 0,
103 .scope = RT_SCOPE_HOST,
104 },
105 [RTN_BROADCAST] = {
106 .error = 0,
107 .scope = RT_SCOPE_LINK,
108 },
109 [RTN_ANYCAST] = {
110 .error = 0,
111 .scope = RT_SCOPE_LINK,
112 },
113 [RTN_MULTICAST] = {
114 .error = 0,
115 .scope = RT_SCOPE_UNIVERSE,
116 },
117 [RTN_BLACKHOLE] = {
118 .error = -EINVAL,
119 .scope = RT_SCOPE_UNIVERSE,
120 },
121 [RTN_UNREACHABLE] = {
122 .error = -EHOSTUNREACH,
123 .scope = RT_SCOPE_UNIVERSE,
124 },
125 [RTN_PROHIBIT] = {
126 .error = -EACCES,
127 .scope = RT_SCOPE_UNIVERSE,
128 },
129 [RTN_THROW] = {
130 .error = -EAGAIN,
131 .scope = RT_SCOPE_UNIVERSE,
132 },
133 [RTN_NAT] = {
134 .error = -EINVAL,
135 .scope = RT_SCOPE_NOWHERE,
136 },
137 [RTN_XRESOLVE] = {
138 .error = -EINVAL,
139 .scope = RT_SCOPE_NOWHERE,
140 },
141};
142
143static void rt_fibinfo_free(struct rtable __rcu **rtp)
144{
145 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
146
147 if (!rt)
148 return;
149
150 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
151 * because we waited an RCU grace period before calling
152 * free_fib_info_rcu()
153 */
154
155 dst_free(&rt->dst);
156}
157
158static void free_nh_exceptions(struct fib_nh *nh)
159{
160 struct fnhe_hash_bucket *hash;
161 int i;
162
163 hash = rcu_dereference_protected(nh->nh_exceptions, 1);
164 if (!hash)
165 return;
166 for (i = 0; i < FNHE_HASH_SIZE; i++) {
167 struct fib_nh_exception *fnhe;
168
169 fnhe = rcu_dereference_protected(hash[i].chain, 1);
170 while (fnhe) {
171 struct fib_nh_exception *next;
172
173 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
174
175 rt_fibinfo_free(&fnhe->fnhe_rth_input);
176 rt_fibinfo_free(&fnhe->fnhe_rth_output);
177
178 kfree(fnhe);
179
180 fnhe = next;
181 }
182 }
183 kfree(hash);
184}
185
186static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
187{
188 int cpu;
189
190 if (!rtp)
191 return;
192
193 for_each_possible_cpu(cpu) {
194 struct rtable *rt;
195
196 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
197 if (rt)
198 dst_free(&rt->dst);
199 }
200 free_percpu(rtp);
201}
202
203/* Release a nexthop info record */
204static void free_fib_info_rcu(struct rcu_head *head)
205{
206 struct fib_info *fi = container_of(head, struct fib_info, rcu);
207
208 change_nexthops(fi) {
209 if (nexthop_nh->nh_dev)
210 dev_put(nexthop_nh->nh_dev);
211 lwtstate_put(nexthop_nh->nh_lwtstate);
212 free_nh_exceptions(nexthop_nh);
213 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
214 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
215 } endfor_nexthops(fi);
216
217 if (fi->fib_metrics != (u32 *) dst_default_metrics)
218 kfree(fi->fib_metrics);
219 kfree(fi);
220}
221
222void free_fib_info(struct fib_info *fi)
223{
224 if (fi->fib_dead == 0) {
225 pr_warn("Freeing alive fib_info %p\n", fi);
226 return;
227 }
228 fib_info_cnt--;
229#ifdef CONFIG_IP_ROUTE_CLASSID
230 change_nexthops(fi) {
231 if (nexthop_nh->nh_tclassid)
232 fi->fib_net->ipv4.fib_num_tclassid_users--;
233 } endfor_nexthops(fi);
234#endif
235 call_rcu(&fi->rcu, free_fib_info_rcu);
236}
237
238void fib_release_info(struct fib_info *fi)
239{
240 spin_lock_bh(&fib_info_lock);
241 if (fi && --fi->fib_treeref == 0) {
242 hlist_del(&fi->fib_hash);
243 if (fi->fib_prefsrc)
244 hlist_del(&fi->fib_lhash);
245 change_nexthops(fi) {
246 if (!nexthop_nh->nh_dev)
247 continue;
248 hlist_del(&nexthop_nh->nh_hash);
249 } endfor_nexthops(fi)
250 fi->fib_dead = 1;
251 fib_info_put(fi);
252 }
253 spin_unlock_bh(&fib_info_lock);
254}
255
256static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
257{
258 const struct fib_nh *onh = ofi->fib_nh;
259
260 for_nexthops(fi) {
261 if (nh->nh_oif != onh->nh_oif ||
262 nh->nh_gw != onh->nh_gw ||
263 nh->nh_scope != onh->nh_scope ||
264#ifdef CONFIG_IP_ROUTE_MULTIPATH
265 nh->nh_weight != onh->nh_weight ||
266#endif
267#ifdef CONFIG_IP_ROUTE_CLASSID
268 nh->nh_tclassid != onh->nh_tclassid ||
269#endif
270 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
271 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
272 return -1;
273 onh++;
274 } endfor_nexthops(fi);
275 return 0;
276}
277
278static inline unsigned int fib_devindex_hashfn(unsigned int val)
279{
280 unsigned int mask = DEVINDEX_HASHSIZE - 1;
281
282 return (val ^
283 (val >> DEVINDEX_HASHBITS) ^
284 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
285}
286
287static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
288{
289 unsigned int mask = (fib_info_hash_size - 1);
290 unsigned int val = fi->fib_nhs;
291
292 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
293 val ^= (__force u32)fi->fib_prefsrc;
294 val ^= fi->fib_priority;
295 for_nexthops(fi) {
296 val ^= fib_devindex_hashfn(nh->nh_oif);
297 } endfor_nexthops(fi)
298
299 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
300}
301
302static struct fib_info *fib_find_info(const struct fib_info *nfi)
303{
304 struct hlist_head *head;
305 struct fib_info *fi;
306 unsigned int hash;
307
308 hash = fib_info_hashfn(nfi);
309 head = &fib_info_hash[hash];
310
311 hlist_for_each_entry(fi, head, fib_hash) {
312 if (!net_eq(fi->fib_net, nfi->fib_net))
313 continue;
314 if (fi->fib_nhs != nfi->fib_nhs)
315 continue;
316 if (nfi->fib_protocol == fi->fib_protocol &&
317 nfi->fib_scope == fi->fib_scope &&
318 nfi->fib_prefsrc == fi->fib_prefsrc &&
319 nfi->fib_priority == fi->fib_priority &&
320 nfi->fib_type == fi->fib_type &&
321 memcmp(nfi->fib_metrics, fi->fib_metrics,
322 sizeof(u32) * RTAX_MAX) == 0 &&
323 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
324 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
325 return fi;
326 }
327
328 return NULL;
329}
330
331/* Check, that the gateway is already configured.
332 * Used only by redirect accept routine.
333 */
334int ip_fib_check_default(__be32 gw, struct net_device *dev)
335{
336 struct hlist_head *head;
337 struct fib_nh *nh;
338 unsigned int hash;
339
340 spin_lock(&fib_info_lock);
341
342 hash = fib_devindex_hashfn(dev->ifindex);
343 head = &fib_info_devhash[hash];
344 hlist_for_each_entry(nh, head, nh_hash) {
345 if (nh->nh_dev == dev &&
346 nh->nh_gw == gw &&
347 !(nh->nh_flags & RTNH_F_DEAD)) {
348 spin_unlock(&fib_info_lock);
349 return 0;
350 }
351 }
352
353 spin_unlock(&fib_info_lock);
354
355 return -1;
356}
357
358static inline size_t fib_nlmsg_size(struct fib_info *fi)
359{
360 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
361 + nla_total_size(4) /* RTA_TABLE */
362 + nla_total_size(4) /* RTA_DST */
363 + nla_total_size(4) /* RTA_PRIORITY */
364 + nla_total_size(4) /* RTA_PREFSRC */
365 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
366
367 /* space for nested metrics */
368 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
369
370 if (fi->fib_nhs) {
371 size_t nh_encapsize = 0;
372 /* Also handles the special case fib_nhs == 1 */
373
374 /* each nexthop is packed in an attribute */
375 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
376
377 /* may contain flow and gateway attribute */
378 nhsize += 2 * nla_total_size(4);
379
380 /* grab encap info */
381 for_nexthops(fi) {
382 if (nh->nh_lwtstate) {
383 /* RTA_ENCAP_TYPE */
384 nh_encapsize += lwtunnel_get_encap_size(
385 nh->nh_lwtstate);
386 /* RTA_ENCAP */
387 nh_encapsize += nla_total_size(2);
388 }
389 } endfor_nexthops(fi);
390
391 /* all nexthops are packed in a nested attribute */
392 payload += nla_total_size((fi->fib_nhs * nhsize) +
393 nh_encapsize);
394
395 }
396
397 return payload;
398}
399
400void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
401 int dst_len, u32 tb_id, const struct nl_info *info,
402 unsigned int nlm_flags)
403{
404 struct sk_buff *skb;
405 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
406 int err = -ENOBUFS;
407
408 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
409 if (!skb)
410 goto errout;
411
412 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
413 fa->fa_type, key, dst_len,
414 fa->fa_tos, fa->fa_info, nlm_flags);
415 if (err < 0) {
416 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
417 WARN_ON(err == -EMSGSIZE);
418 kfree_skb(skb);
419 goto errout;
420 }
421 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
422 info->nlh, GFP_KERNEL);
423 return;
424errout:
425 if (err < 0)
426 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
427}
428
429static int fib_detect_death(struct fib_info *fi, int order,
430 struct fib_info **last_resort, int *last_idx,
431 int dflt)
432{
433 struct neighbour *n;
434 int state = NUD_NONE;
435
436 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
437 if (n) {
438 state = n->nud_state;
439 neigh_release(n);
440 } else {
441 return 0;
442 }
443 if (state == NUD_REACHABLE)
444 return 0;
445 if ((state & NUD_VALID) && order != dflt)
446 return 0;
447 if ((state & NUD_VALID) ||
448 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
449 *last_resort = fi;
450 *last_idx = order;
451 }
452 return 1;
453}
454
455#ifdef CONFIG_IP_ROUTE_MULTIPATH
456
457static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
458{
459 int nhs = 0;
460
461 while (rtnh_ok(rtnh, remaining)) {
462 nhs++;
463 rtnh = rtnh_next(rtnh, &remaining);
464 }
465
466 /* leftover implies invalid nexthop configuration, discard it */
467 return remaining > 0 ? 0 : nhs;
468}
469
470static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
471 int remaining, struct fib_config *cfg)
472{
473 struct net *net = cfg->fc_nlinfo.nl_net;
474 int ret;
475
476 change_nexthops(fi) {
477 int attrlen;
478
479 if (!rtnh_ok(rtnh, remaining))
480 return -EINVAL;
481
482 nexthop_nh->nh_flags =
483 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
484 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
485 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
486
487 attrlen = rtnh_attrlen(rtnh);
488 if (attrlen > 0) {
489 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
490
491 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
492 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
493#ifdef CONFIG_IP_ROUTE_CLASSID
494 nla = nla_find(attrs, attrlen, RTA_FLOW);
495 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
496 if (nexthop_nh->nh_tclassid)
497 fi->fib_net->ipv4.fib_num_tclassid_users++;
498#endif
499 nla = nla_find(attrs, attrlen, RTA_ENCAP);
500 if (nla) {
501 struct lwtunnel_state *lwtstate;
502 struct net_device *dev = NULL;
503 struct nlattr *nla_entype;
504
505 nla_entype = nla_find(attrs, attrlen,
506 RTA_ENCAP_TYPE);
507 if (!nla_entype)
508 goto err_inval;
509 if (cfg->fc_oif)
510 dev = __dev_get_by_index(net, cfg->fc_oif);
511 ret = lwtunnel_build_state(dev, nla_get_u16(
512 nla_entype),
513 nla, AF_INET, cfg,
514 &lwtstate);
515 if (ret)
516 goto errout;
517 nexthop_nh->nh_lwtstate =
518 lwtstate_get(lwtstate);
519 }
520 }
521
522 rtnh = rtnh_next(rtnh, &remaining);
523 } endfor_nexthops(fi);
524
525 return 0;
526
527err_inval:
528 ret = -EINVAL;
529
530errout:
531 return ret;
532}
533
534static void fib_rebalance(struct fib_info *fi)
535{
536 int total;
537 int w;
538 struct in_device *in_dev;
539
540 if (fi->fib_nhs < 2)
541 return;
542
543 total = 0;
544 for_nexthops(fi) {
545 if (nh->nh_flags & RTNH_F_DEAD)
546 continue;
547
548 in_dev = __in_dev_get_rtnl(nh->nh_dev);
549
550 if (in_dev &&
551 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
552 nh->nh_flags & RTNH_F_LINKDOWN)
553 continue;
554
555 total += nh->nh_weight;
556 } endfor_nexthops(fi);
557
558 w = 0;
559 change_nexthops(fi) {
560 int upper_bound;
561
562 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
563
564 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
565 upper_bound = -1;
566 } else if (in_dev &&
567 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
568 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
569 upper_bound = -1;
570 } else {
571 w += nexthop_nh->nh_weight;
572 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
573 total) - 1;
574 }
575
576 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
577 } endfor_nexthops(fi);
578
579 net_get_random_once(&fib_multipath_secret,
580 sizeof(fib_multipath_secret));
581}
582
583static inline void fib_add_weight(struct fib_info *fi,
584 const struct fib_nh *nh)
585{
586 fi->fib_weight += nh->nh_weight;
587}
588
589#else /* CONFIG_IP_ROUTE_MULTIPATH */
590
591#define fib_rebalance(fi) do { } while (0)
592#define fib_add_weight(fi, nh) do { } while (0)
593
594#endif /* CONFIG_IP_ROUTE_MULTIPATH */
595
596static int fib_encap_match(struct net *net, u16 encap_type,
597 struct nlattr *encap,
598 int oif, const struct fib_nh *nh,
599 const struct fib_config *cfg)
600{
601 struct lwtunnel_state *lwtstate;
602 struct net_device *dev = NULL;
603 int ret, result = 0;
604
605 if (encap_type == LWTUNNEL_ENCAP_NONE)
606 return 0;
607
608 if (oif)
609 dev = __dev_get_by_index(net, oif);
610 ret = lwtunnel_build_state(dev, encap_type, encap,
611 AF_INET, cfg, &lwtstate);
612 if (!ret) {
613 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
614 lwtstate_free(lwtstate);
615 }
616
617 return result;
618}
619
620int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
621{
622 struct net *net = cfg->fc_nlinfo.nl_net;
623#ifdef CONFIG_IP_ROUTE_MULTIPATH
624 struct rtnexthop *rtnh;
625 int remaining;
626#endif
627
628 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
629 return 1;
630
631 if (cfg->fc_oif || cfg->fc_gw) {
632 if (cfg->fc_encap) {
633 if (fib_encap_match(net, cfg->fc_encap_type,
634 cfg->fc_encap, cfg->fc_oif,
635 fi->fib_nh, cfg))
636 return 1;
637 }
638 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
639 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
640 return 0;
641 return 1;
642 }
643
644#ifdef CONFIG_IP_ROUTE_MULTIPATH
645 if (!cfg->fc_mp)
646 return 0;
647
648 rtnh = cfg->fc_mp;
649 remaining = cfg->fc_mp_len;
650
651 for_nexthops(fi) {
652 int attrlen;
653
654 if (!rtnh_ok(rtnh, remaining))
655 return -EINVAL;
656
657 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
658 return 1;
659
660 attrlen = rtnh_attrlen(rtnh);
661 if (attrlen > 0) {
662 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
663
664 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
665 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
666 return 1;
667#ifdef CONFIG_IP_ROUTE_CLASSID
668 nla = nla_find(attrs, attrlen, RTA_FLOW);
669 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
670 return 1;
671#endif
672 }
673
674 rtnh = rtnh_next(rtnh, &remaining);
675 } endfor_nexthops(fi);
676#endif
677 return 0;
678}
679
680
681/*
682 * Picture
683 * -------
684 *
685 * Semantics of nexthop is very messy by historical reasons.
686 * We have to take into account, that:
687 * a) gateway can be actually local interface address,
688 * so that gatewayed route is direct.
689 * b) gateway must be on-link address, possibly
690 * described not by an ifaddr, but also by a direct route.
691 * c) If both gateway and interface are specified, they should not
692 * contradict.
693 * d) If we use tunnel routes, gateway could be not on-link.
694 *
695 * Attempt to reconcile all of these (alas, self-contradictory) conditions
696 * results in pretty ugly and hairy code with obscure logic.
697 *
698 * I chose to generalized it instead, so that the size
699 * of code does not increase practically, but it becomes
700 * much more general.
701 * Every prefix is assigned a "scope" value: "host" is local address,
702 * "link" is direct route,
703 * [ ... "site" ... "interior" ... ]
704 * and "universe" is true gateway route with global meaning.
705 *
706 * Every prefix refers to a set of "nexthop"s (gw, oif),
707 * where gw must have narrower scope. This recursion stops
708 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
709 * which means that gw is forced to be on link.
710 *
711 * Code is still hairy, but now it is apparently logically
712 * consistent and very flexible. F.e. as by-product it allows
713 * to co-exists in peace independent exterior and interior
714 * routing processes.
715 *
716 * Normally it looks as following.
717 *
718 * {universe prefix} -> (gw, oif) [scope link]
719 * |
720 * |-> {link prefix} -> (gw, oif) [scope local]
721 * |
722 * |-> {local prefix} (terminal node)
723 */
724static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
725 struct fib_nh *nh)
726{
727 int err = 0;
728 struct net *net;
729 struct net_device *dev;
730
731 net = cfg->fc_nlinfo.nl_net;
732 if (nh->nh_gw) {
733 struct fib_result res;
734
735 if (nh->nh_flags & RTNH_F_ONLINK) {
736 unsigned int addr_type;
737
738 if (cfg->fc_scope >= RT_SCOPE_LINK)
739 return -EINVAL;
740 dev = __dev_get_by_index(net, nh->nh_oif);
741 if (!dev)
742 return -ENODEV;
743 if (!(dev->flags & IFF_UP))
744 return -ENETDOWN;
745 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
746 if (addr_type != RTN_UNICAST)
747 return -EINVAL;
748 if (!netif_carrier_ok(dev))
749 nh->nh_flags |= RTNH_F_LINKDOWN;
750 nh->nh_dev = dev;
751 dev_hold(dev);
752 nh->nh_scope = RT_SCOPE_LINK;
753 return 0;
754 }
755 rcu_read_lock();
756 {
757 struct fib_table *tbl = NULL;
758 struct flowi4 fl4 = {
759 .daddr = nh->nh_gw,
760 .flowi4_scope = cfg->fc_scope + 1,
761 .flowi4_oif = nh->nh_oif,
762 .flowi4_iif = LOOPBACK_IFINDEX,
763 };
764
765 /* It is not necessary, but requires a bit of thinking */
766 if (fl4.flowi4_scope < RT_SCOPE_LINK)
767 fl4.flowi4_scope = RT_SCOPE_LINK;
768
769 if (cfg->fc_table)
770 tbl = fib_get_table(net, cfg->fc_table);
771
772 if (tbl)
773 err = fib_table_lookup(tbl, &fl4, &res,
774 FIB_LOOKUP_IGNORE_LINKSTATE |
775 FIB_LOOKUP_NOREF);
776
777 /* on error or if no table given do full lookup. This
778 * is needed for example when nexthops are in the local
779 * table rather than the given table
780 */
781 if (!tbl || err) {
782 err = fib_lookup(net, &fl4, &res,
783 FIB_LOOKUP_IGNORE_LINKSTATE);
784 }
785
786 if (err) {
787 rcu_read_unlock();
788 return err;
789 }
790 }
791 err = -EINVAL;
792 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
793 goto out;
794 nh->nh_scope = res.scope;
795 nh->nh_oif = FIB_RES_OIF(res);
796 nh->nh_dev = dev = FIB_RES_DEV(res);
797 if (!dev)
798 goto out;
799 dev_hold(dev);
800 if (!netif_carrier_ok(dev))
801 nh->nh_flags |= RTNH_F_LINKDOWN;
802 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
803 } else {
804 struct in_device *in_dev;
805
806 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
807 return -EINVAL;
808
809 rcu_read_lock();
810 err = -ENODEV;
811 in_dev = inetdev_by_index(net, nh->nh_oif);
812 if (!in_dev)
813 goto out;
814 err = -ENETDOWN;
815 if (!(in_dev->dev->flags & IFF_UP))
816 goto out;
817 nh->nh_dev = in_dev->dev;
818 dev_hold(nh->nh_dev);
819 nh->nh_scope = RT_SCOPE_HOST;
820 if (!netif_carrier_ok(nh->nh_dev))
821 nh->nh_flags |= RTNH_F_LINKDOWN;
822 err = 0;
823 }
824out:
825 rcu_read_unlock();
826 return err;
827}
828
829static inline unsigned int fib_laddr_hashfn(__be32 val)
830{
831 unsigned int mask = (fib_info_hash_size - 1);
832
833 return ((__force u32)val ^
834 ((__force u32)val >> 7) ^
835 ((__force u32)val >> 14)) & mask;
836}
837
838static struct hlist_head *fib_info_hash_alloc(int bytes)
839{
840 if (bytes <= PAGE_SIZE)
841 return kzalloc(bytes, GFP_KERNEL);
842 else
843 return (struct hlist_head *)
844 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
845 get_order(bytes));
846}
847
848static void fib_info_hash_free(struct hlist_head *hash, int bytes)
849{
850 if (!hash)
851 return;
852
853 if (bytes <= PAGE_SIZE)
854 kfree(hash);
855 else
856 free_pages((unsigned long) hash, get_order(bytes));
857}
858
859static void fib_info_hash_move(struct hlist_head *new_info_hash,
860 struct hlist_head *new_laddrhash,
861 unsigned int new_size)
862{
863 struct hlist_head *old_info_hash, *old_laddrhash;
864 unsigned int old_size = fib_info_hash_size;
865 unsigned int i, bytes;
866
867 spin_lock_bh(&fib_info_lock);
868 old_info_hash = fib_info_hash;
869 old_laddrhash = fib_info_laddrhash;
870 fib_info_hash_size = new_size;
871
872 for (i = 0; i < old_size; i++) {
873 struct hlist_head *head = &fib_info_hash[i];
874 struct hlist_node *n;
875 struct fib_info *fi;
876
877 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
878 struct hlist_head *dest;
879 unsigned int new_hash;
880
881 new_hash = fib_info_hashfn(fi);
882 dest = &new_info_hash[new_hash];
883 hlist_add_head(&fi->fib_hash, dest);
884 }
885 }
886 fib_info_hash = new_info_hash;
887
888 for (i = 0; i < old_size; i++) {
889 struct hlist_head *lhead = &fib_info_laddrhash[i];
890 struct hlist_node *n;
891 struct fib_info *fi;
892
893 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
894 struct hlist_head *ldest;
895 unsigned int new_hash;
896
897 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
898 ldest = &new_laddrhash[new_hash];
899 hlist_add_head(&fi->fib_lhash, ldest);
900 }
901 }
902 fib_info_laddrhash = new_laddrhash;
903
904 spin_unlock_bh(&fib_info_lock);
905
906 bytes = old_size * sizeof(struct hlist_head *);
907 fib_info_hash_free(old_info_hash, bytes);
908 fib_info_hash_free(old_laddrhash, bytes);
909}
910
911__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
912{
913 nh->nh_saddr = inet_select_addr(nh->nh_dev,
914 nh->nh_gw,
915 nh->nh_parent->fib_scope);
916 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
917
918 return nh->nh_saddr;
919}
920
921static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
922{
923 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
924 fib_prefsrc != cfg->fc_dst) {
925 u32 tb_id = cfg->fc_table;
926 int rc;
927
928 if (tb_id == RT_TABLE_MAIN)
929 tb_id = RT_TABLE_LOCAL;
930
931 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
932 fib_prefsrc, tb_id);
933
934 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
935 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
936 fib_prefsrc, RT_TABLE_LOCAL);
937 }
938
939 if (rc != RTN_LOCAL)
940 return false;
941 }
942 return true;
943}
944
945static int
946fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
947{
948 bool ecn_ca = false;
949 struct nlattr *nla;
950 int remaining;
951
952 if (!cfg->fc_mx)
953 return 0;
954
955 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
956 int type = nla_type(nla);
957 u32 val;
958
959 if (!type)
960 continue;
961 if (type > RTAX_MAX)
962 return -EINVAL;
963
964 if (type == RTAX_CC_ALGO) {
965 char tmp[TCP_CA_NAME_MAX];
966
967 nla_strlcpy(tmp, nla, sizeof(tmp));
968 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
969 if (val == TCP_CA_UNSPEC)
970 return -EINVAL;
971 } else {
972 val = nla_get_u32(nla);
973 }
974 if (type == RTAX_ADVMSS && val > 65535 - 40)
975 val = 65535 - 40;
976 if (type == RTAX_MTU && val > 65535 - 15)
977 val = 65535 - 15;
978 if (type == RTAX_HOPLIMIT && val > 255)
979 val = 255;
980 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
981 return -EINVAL;
982 fi->fib_metrics[type - 1] = val;
983 }
984
985 if (ecn_ca)
986 fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
987
988 return 0;
989}
990
991struct fib_info *fib_create_info(struct fib_config *cfg)
992{
993 int err;
994 struct fib_info *fi = NULL;
995 struct fib_info *ofi;
996 int nhs = 1;
997 struct net *net = cfg->fc_nlinfo.nl_net;
998
999 if (cfg->fc_type > RTN_MAX)
1000 goto err_inval;
1001
1002 /* Fast check to catch the most weird cases */
1003 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
1004 goto err_inval;
1005
1006#ifdef CONFIG_IP_ROUTE_MULTIPATH
1007 if (cfg->fc_mp) {
1008 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
1009 if (nhs == 0)
1010 goto err_inval;
1011 }
1012#endif
1013
1014 err = -ENOBUFS;
1015 if (fib_info_cnt >= fib_info_hash_size) {
1016 unsigned int new_size = fib_info_hash_size << 1;
1017 struct hlist_head *new_info_hash;
1018 struct hlist_head *new_laddrhash;
1019 unsigned int bytes;
1020
1021 if (!new_size)
1022 new_size = 16;
1023 bytes = new_size * sizeof(struct hlist_head *);
1024 new_info_hash = fib_info_hash_alloc(bytes);
1025 new_laddrhash = fib_info_hash_alloc(bytes);
1026 if (!new_info_hash || !new_laddrhash) {
1027 fib_info_hash_free(new_info_hash, bytes);
1028 fib_info_hash_free(new_laddrhash, bytes);
1029 } else
1030 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1031
1032 if (!fib_info_hash_size)
1033 goto failure;
1034 }
1035
1036 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1037 if (!fi)
1038 goto failure;
1039 fib_info_cnt++;
1040 if (cfg->fc_mx) {
1041 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
1042 if (!fi->fib_metrics)
1043 goto failure;
1044 } else
1045 fi->fib_metrics = (u32 *) dst_default_metrics;
1046
1047 fi->fib_net = net;
1048 fi->fib_protocol = cfg->fc_protocol;
1049 fi->fib_scope = cfg->fc_scope;
1050 fi->fib_flags = cfg->fc_flags;
1051 fi->fib_priority = cfg->fc_priority;
1052 fi->fib_prefsrc = cfg->fc_prefsrc;
1053 fi->fib_type = cfg->fc_type;
1054
1055 fi->fib_nhs = nhs;
1056 change_nexthops(fi) {
1057 nexthop_nh->nh_parent = fi;
1058 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1059 if (!nexthop_nh->nh_pcpu_rth_output)
1060 goto failure;
1061 } endfor_nexthops(fi)
1062
1063 err = fib_convert_metrics(fi, cfg);
1064 if (err)
1065 goto failure;
1066
1067 if (cfg->fc_mp) {
1068#ifdef CONFIG_IP_ROUTE_MULTIPATH
1069 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
1070 if (err != 0)
1071 goto failure;
1072 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
1073 goto err_inval;
1074 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
1075 goto err_inval;
1076#ifdef CONFIG_IP_ROUTE_CLASSID
1077 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
1078 goto err_inval;
1079#endif
1080#else
1081 goto err_inval;
1082#endif
1083 } else {
1084 struct fib_nh *nh = fi->fib_nh;
1085
1086 if (cfg->fc_encap) {
1087 struct lwtunnel_state *lwtstate;
1088 struct net_device *dev = NULL;
1089
1090 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE)
1091 goto err_inval;
1092 if (cfg->fc_oif)
1093 dev = __dev_get_by_index(net, cfg->fc_oif);
1094 err = lwtunnel_build_state(dev, cfg->fc_encap_type,
1095 cfg->fc_encap, AF_INET, cfg,
1096 &lwtstate);
1097 if (err)
1098 goto failure;
1099
1100 nh->nh_lwtstate = lwtstate_get(lwtstate);
1101 }
1102 nh->nh_oif = cfg->fc_oif;
1103 nh->nh_gw = cfg->fc_gw;
1104 nh->nh_flags = cfg->fc_flags;
1105#ifdef CONFIG_IP_ROUTE_CLASSID
1106 nh->nh_tclassid = cfg->fc_flow;
1107 if (nh->nh_tclassid)
1108 fi->fib_net->ipv4.fib_num_tclassid_users++;
1109#endif
1110#ifdef CONFIG_IP_ROUTE_MULTIPATH
1111 nh->nh_weight = 1;
1112#endif
1113 }
1114
1115 if (fib_props[cfg->fc_type].error) {
1116 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
1117 goto err_inval;
1118 goto link_it;
1119 } else {
1120 switch (cfg->fc_type) {
1121 case RTN_UNICAST:
1122 case RTN_LOCAL:
1123 case RTN_BROADCAST:
1124 case RTN_ANYCAST:
1125 case RTN_MULTICAST:
1126 break;
1127 default:
1128 goto err_inval;
1129 }
1130 }
1131
1132 if (cfg->fc_scope > RT_SCOPE_HOST)
1133 goto err_inval;
1134
1135 if (cfg->fc_scope == RT_SCOPE_HOST) {
1136 struct fib_nh *nh = fi->fib_nh;
1137
1138 /* Local address is added. */
1139 if (nhs != 1 || nh->nh_gw)
1140 goto err_inval;
1141 nh->nh_scope = RT_SCOPE_NOWHERE;
1142 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1143 err = -ENODEV;
1144 if (!nh->nh_dev)
1145 goto failure;
1146 } else {
1147 int linkdown = 0;
1148
1149 change_nexthops(fi) {
1150 err = fib_check_nh(cfg, fi, nexthop_nh);
1151 if (err != 0)
1152 goto failure;
1153 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1154 linkdown++;
1155 } endfor_nexthops(fi)
1156 if (linkdown == fi->fib_nhs)
1157 fi->fib_flags |= RTNH_F_LINKDOWN;
1158 }
1159
1160 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc))
1161 goto err_inval;
1162
1163 change_nexthops(fi) {
1164 fib_info_update_nh_saddr(net, nexthop_nh);
1165 fib_add_weight(fi, nexthop_nh);
1166 } endfor_nexthops(fi)
1167
1168 fib_rebalance(fi);
1169
1170link_it:
1171 ofi = fib_find_info(fi);
1172 if (ofi) {
1173 fi->fib_dead = 1;
1174 free_fib_info(fi);
1175 ofi->fib_treeref++;
1176 return ofi;
1177 }
1178
1179 fi->fib_treeref++;
1180 atomic_inc(&fi->fib_clntref);
1181 spin_lock_bh(&fib_info_lock);
1182 hlist_add_head(&fi->fib_hash,
1183 &fib_info_hash[fib_info_hashfn(fi)]);
1184 if (fi->fib_prefsrc) {
1185 struct hlist_head *head;
1186
1187 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1188 hlist_add_head(&fi->fib_lhash, head);
1189 }
1190 change_nexthops(fi) {
1191 struct hlist_head *head;
1192 unsigned int hash;
1193
1194 if (!nexthop_nh->nh_dev)
1195 continue;
1196 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1197 head = &fib_info_devhash[hash];
1198 hlist_add_head(&nexthop_nh->nh_hash, head);
1199 } endfor_nexthops(fi)
1200 spin_unlock_bh(&fib_info_lock);
1201 return fi;
1202
1203err_inval:
1204 err = -EINVAL;
1205
1206failure:
1207 if (fi) {
1208 fi->fib_dead = 1;
1209 free_fib_info(fi);
1210 }
1211
1212 return ERR_PTR(err);
1213}
1214
1215int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1216 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1217 struct fib_info *fi, unsigned int flags)
1218{
1219 struct nlmsghdr *nlh;
1220 struct rtmsg *rtm;
1221
1222 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1223 if (!nlh)
1224 return -EMSGSIZE;
1225
1226 rtm = nlmsg_data(nlh);
1227 rtm->rtm_family = AF_INET;
1228 rtm->rtm_dst_len = dst_len;
1229 rtm->rtm_src_len = 0;
1230 rtm->rtm_tos = tos;
1231 if (tb_id < 256)
1232 rtm->rtm_table = tb_id;
1233 else
1234 rtm->rtm_table = RT_TABLE_COMPAT;
1235 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1236 goto nla_put_failure;
1237 rtm->rtm_type = type;
1238 rtm->rtm_flags = fi->fib_flags;
1239 rtm->rtm_scope = fi->fib_scope;
1240 rtm->rtm_protocol = fi->fib_protocol;
1241
1242 if (rtm->rtm_dst_len &&
1243 nla_put_in_addr(skb, RTA_DST, dst))
1244 goto nla_put_failure;
1245 if (fi->fib_priority &&
1246 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1247 goto nla_put_failure;
1248 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
1249 goto nla_put_failure;
1250
1251 if (fi->fib_prefsrc &&
1252 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1253 goto nla_put_failure;
1254 if (fi->fib_nhs == 1) {
1255 struct in_device *in_dev;
1256
1257 if (fi->fib_nh->nh_gw &&
1258 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1259 goto nla_put_failure;
1260 if (fi->fib_nh->nh_oif &&
1261 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1262 goto nla_put_failure;
1263 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1264 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev);
1265 if (in_dev &&
1266 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1267 rtm->rtm_flags |= RTNH_F_DEAD;
1268 }
1269#ifdef CONFIG_IP_ROUTE_CLASSID
1270 if (fi->fib_nh[0].nh_tclassid &&
1271 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1272 goto nla_put_failure;
1273#endif
1274 if (fi->fib_nh->nh_lwtstate)
1275 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate);
1276 }
1277#ifdef CONFIG_IP_ROUTE_MULTIPATH
1278 if (fi->fib_nhs > 1) {
1279 struct rtnexthop *rtnh;
1280 struct nlattr *mp;
1281
1282 mp = nla_nest_start(skb, RTA_MULTIPATH);
1283 if (!mp)
1284 goto nla_put_failure;
1285
1286 for_nexthops(fi) {
1287 struct in_device *in_dev;
1288
1289 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1290 if (!rtnh)
1291 goto nla_put_failure;
1292
1293 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1294 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1295 in_dev = __in_dev_get_rtnl(nh->nh_dev);
1296 if (in_dev &&
1297 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1298 rtnh->rtnh_flags |= RTNH_F_DEAD;
1299 }
1300 rtnh->rtnh_hops = nh->nh_weight - 1;
1301 rtnh->rtnh_ifindex = nh->nh_oif;
1302
1303 if (nh->nh_gw &&
1304 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1305 goto nla_put_failure;
1306#ifdef CONFIG_IP_ROUTE_CLASSID
1307 if (nh->nh_tclassid &&
1308 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1309 goto nla_put_failure;
1310#endif
1311 if (nh->nh_lwtstate)
1312 lwtunnel_fill_encap(skb, nh->nh_lwtstate);
1313 /* length of rtnetlink header + attributes */
1314 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1315 } endfor_nexthops(fi);
1316
1317 nla_nest_end(skb, mp);
1318 }
1319#endif
1320 nlmsg_end(skb, nlh);
1321 return 0;
1322
1323nla_put_failure:
1324 nlmsg_cancel(skb, nlh);
1325 return -EMSGSIZE;
1326}
1327
1328/*
1329 * Update FIB if:
1330 * - local address disappeared -> we must delete all the entries
1331 * referring to it.
1332 * - device went down -> we must shutdown all nexthops going via it.
1333 */
1334int fib_sync_down_addr(struct net *net, __be32 local)
1335{
1336 int ret = 0;
1337 unsigned int hash = fib_laddr_hashfn(local);
1338 struct hlist_head *head = &fib_info_laddrhash[hash];
1339 struct fib_info *fi;
1340
1341 if (!fib_info_laddrhash || local == 0)
1342 return 0;
1343
1344 hlist_for_each_entry(fi, head, fib_lhash) {
1345 if (!net_eq(fi->fib_net, net))
1346 continue;
1347 if (fi->fib_prefsrc == local) {
1348 fi->fib_flags |= RTNH_F_DEAD;
1349 ret++;
1350 }
1351 }
1352 return ret;
1353}
1354
1355/* Event force Flags Description
1356 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1357 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1358 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1359 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1360 */
1361int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1362{
1363 int ret = 0;
1364 int scope = RT_SCOPE_NOWHERE;
1365 struct fib_info *prev_fi = NULL;
1366 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1367 struct hlist_head *head = &fib_info_devhash[hash];
1368 struct fib_nh *nh;
1369
1370 if (force)
1371 scope = -1;
1372
1373 hlist_for_each_entry(nh, head, nh_hash) {
1374 struct fib_info *fi = nh->nh_parent;
1375 int dead;
1376
1377 BUG_ON(!fi->fib_nhs);
1378 if (nh->nh_dev != dev || fi == prev_fi)
1379 continue;
1380 prev_fi = fi;
1381 dead = 0;
1382 change_nexthops(fi) {
1383 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1384 dead++;
1385 else if (nexthop_nh->nh_dev == dev &&
1386 nexthop_nh->nh_scope != scope) {
1387 switch (event) {
1388 case NETDEV_DOWN:
1389 case NETDEV_UNREGISTER:
1390 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1391 /* fall through */
1392 case NETDEV_CHANGE:
1393 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1394 break;
1395 }
1396 dead++;
1397 }
1398#ifdef CONFIG_IP_ROUTE_MULTIPATH
1399 if (event == NETDEV_UNREGISTER &&
1400 nexthop_nh->nh_dev == dev) {
1401 dead = fi->fib_nhs;
1402 break;
1403 }
1404#endif
1405 } endfor_nexthops(fi)
1406 if (dead == fi->fib_nhs) {
1407 switch (event) {
1408 case NETDEV_DOWN:
1409 case NETDEV_UNREGISTER:
1410 fi->fib_flags |= RTNH_F_DEAD;
1411 /* fall through */
1412 case NETDEV_CHANGE:
1413 fi->fib_flags |= RTNH_F_LINKDOWN;
1414 break;
1415 }
1416 ret++;
1417 }
1418
1419 fib_rebalance(fi);
1420 }
1421
1422 return ret;
1423}
1424
1425/* Must be invoked inside of an RCU protected region. */
1426void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1427{
1428 struct fib_info *fi = NULL, *last_resort = NULL;
1429 struct hlist_head *fa_head = res->fa_head;
1430 struct fib_table *tb = res->table;
1431 u8 slen = 32 - res->prefixlen;
1432 int order = -1, last_idx = -1;
1433 struct fib_alias *fa, *fa1 = NULL;
1434 u32 last_prio = res->fi->fib_priority;
1435 u8 last_tos = 0;
1436
1437 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1438 struct fib_info *next_fi = fa->fa_info;
1439
1440 if (fa->fa_slen != slen)
1441 continue;
1442 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1443 continue;
1444 if (fa->tb_id != tb->tb_id)
1445 continue;
1446 if (next_fi->fib_priority > last_prio &&
1447 fa->fa_tos == last_tos) {
1448 if (last_tos)
1449 continue;
1450 break;
1451 }
1452 if (next_fi->fib_flags & RTNH_F_DEAD)
1453 continue;
1454 last_tos = fa->fa_tos;
1455 last_prio = next_fi->fib_priority;
1456
1457 if (next_fi->fib_scope != res->scope ||
1458 fa->fa_type != RTN_UNICAST)
1459 continue;
1460 if (!next_fi->fib_nh[0].nh_gw ||
1461 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1462 continue;
1463
1464 fib_alias_accessed(fa);
1465
1466 if (!fi) {
1467 if (next_fi != res->fi)
1468 break;
1469 fa1 = fa;
1470 } else if (!fib_detect_death(fi, order, &last_resort,
1471 &last_idx, fa1->fa_default)) {
1472 fib_result_assign(res, fi);
1473 fa1->fa_default = order;
1474 goto out;
1475 }
1476 fi = next_fi;
1477 order++;
1478 }
1479
1480 if (order <= 0 || !fi) {
1481 if (fa1)
1482 fa1->fa_default = -1;
1483 goto out;
1484 }
1485
1486 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1487 fa1->fa_default)) {
1488 fib_result_assign(res, fi);
1489 fa1->fa_default = order;
1490 goto out;
1491 }
1492
1493 if (last_idx >= 0)
1494 fib_result_assign(res, last_resort);
1495 fa1->fa_default = last_idx;
1496out:
1497 return;
1498}
1499
1500/*
1501 * Dead device goes up. We wake up dead nexthops.
1502 * It takes sense only on multipath routes.
1503 */
1504int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1505{
1506 struct fib_info *prev_fi;
1507 unsigned int hash;
1508 struct hlist_head *head;
1509 struct fib_nh *nh;
1510 int ret;
1511
1512 if (!(dev->flags & IFF_UP))
1513 return 0;
1514
1515 if (nh_flags & RTNH_F_DEAD) {
1516 unsigned int flags = dev_get_flags(dev);
1517
1518 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1519 nh_flags |= RTNH_F_LINKDOWN;
1520 }
1521
1522 prev_fi = NULL;
1523 hash = fib_devindex_hashfn(dev->ifindex);
1524 head = &fib_info_devhash[hash];
1525 ret = 0;
1526
1527 hlist_for_each_entry(nh, head, nh_hash) {
1528 struct fib_info *fi = nh->nh_parent;
1529 int alive;
1530
1531 BUG_ON(!fi->fib_nhs);
1532 if (nh->nh_dev != dev || fi == prev_fi)
1533 continue;
1534
1535 prev_fi = fi;
1536 alive = 0;
1537 change_nexthops(fi) {
1538 if (!(nexthop_nh->nh_flags & nh_flags)) {
1539 alive++;
1540 continue;
1541 }
1542 if (!nexthop_nh->nh_dev ||
1543 !(nexthop_nh->nh_dev->flags & IFF_UP))
1544 continue;
1545 if (nexthop_nh->nh_dev != dev ||
1546 !__in_dev_get_rtnl(dev))
1547 continue;
1548 alive++;
1549 nexthop_nh->nh_flags &= ~nh_flags;
1550 } endfor_nexthops(fi)
1551
1552 if (alive > 0) {
1553 fi->fib_flags &= ~nh_flags;
1554 ret++;
1555 }
1556
1557 fib_rebalance(fi);
1558 }
1559
1560 return ret;
1561}
1562
1563#ifdef CONFIG_IP_ROUTE_MULTIPATH
1564
1565void fib_select_multipath(struct fib_result *res, int hash)
1566{
1567 struct fib_info *fi = res->fi;
1568
1569 for_nexthops(fi) {
1570 if (hash > atomic_read(&nh->nh_upper_bound))
1571 continue;
1572
1573 res->nh_sel = nhsel;
1574 return;
1575 } endfor_nexthops(fi);
1576
1577 /* Race condition: route has just become dead. */
1578 res->nh_sel = 0;
1579}
1580#endif
1581
1582void fib_select_path(struct net *net, struct fib_result *res,
1583 struct flowi4 *fl4, int mp_hash)
1584{
1585#ifdef CONFIG_IP_ROUTE_MULTIPATH
1586 if (res->fi->fib_nhs > 1 && fl4->flowi4_oif == 0) {
1587 if (mp_hash < 0)
1588 mp_hash = get_hash_from_flowi4(fl4) >> 1;
1589
1590 fib_select_multipath(res, mp_hash);
1591 }
1592 else
1593#endif
1594 if (!res->prefixlen &&
1595 res->table->tb_num_default > 1 &&
1596 res->type == RTN_UNICAST && !fl4->flowi4_oif)
1597 fib_select_default(fl4, res);
1598
1599 if (!fl4->saddr)
1600 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1601}
1602EXPORT_SYMBOL_GPL(fib_select_path);
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#include <linux/hash.h>
33#include <linux/nospec.h>
34
35#include <net/arp.h>
36#include <net/inet_dscp.h>
37#include <net/ip.h>
38#include <net/protocol.h>
39#include <net/route.h>
40#include <net/tcp.h>
41#include <net/sock.h>
42#include <net/ip_fib.h>
43#include <net/ip6_fib.h>
44#include <net/nexthop.h>
45#include <net/netlink.h>
46#include <net/rtnh.h>
47#include <net/lwtunnel.h>
48#include <net/fib_notifier.h>
49#include <net/addrconf.h>
50
51#include "fib_lookup.h"
52
53static DEFINE_SPINLOCK(fib_info_lock);
54static struct hlist_head *fib_info_hash;
55static struct hlist_head *fib_info_laddrhash;
56static unsigned int fib_info_hash_size;
57static unsigned int fib_info_hash_bits;
58static unsigned int fib_info_cnt;
59
60#define DEVINDEX_HASHBITS 8
61#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
62static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
63
64/* for_nexthops and change_nexthops only used when nexthop object
65 * is not set in a fib_info. The logic within can reference fib_nh.
66 */
67#ifdef CONFIG_IP_ROUTE_MULTIPATH
68
69#define for_nexthops(fi) { \
70 int nhsel; const struct fib_nh *nh; \
71 for (nhsel = 0, nh = (fi)->fib_nh; \
72 nhsel < fib_info_num_path((fi)); \
73 nh++, nhsel++)
74
75#define change_nexthops(fi) { \
76 int nhsel; struct fib_nh *nexthop_nh; \
77 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
78 nhsel < fib_info_num_path((fi)); \
79 nexthop_nh++, nhsel++)
80
81#else /* CONFIG_IP_ROUTE_MULTIPATH */
82
83/* Hope, that gcc will optimize it to get rid of dummy loop */
84
85#define for_nexthops(fi) { \
86 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
87 for (nhsel = 0; nhsel < 1; nhsel++)
88
89#define change_nexthops(fi) { \
90 int nhsel; \
91 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
92 for (nhsel = 0; nhsel < 1; nhsel++)
93
94#endif /* CONFIG_IP_ROUTE_MULTIPATH */
95
96#define endfor_nexthops(fi) }
97
98
99const struct fib_prop fib_props[RTN_MAX + 1] = {
100 [RTN_UNSPEC] = {
101 .error = 0,
102 .scope = RT_SCOPE_NOWHERE,
103 },
104 [RTN_UNICAST] = {
105 .error = 0,
106 .scope = RT_SCOPE_UNIVERSE,
107 },
108 [RTN_LOCAL] = {
109 .error = 0,
110 .scope = RT_SCOPE_HOST,
111 },
112 [RTN_BROADCAST] = {
113 .error = 0,
114 .scope = RT_SCOPE_LINK,
115 },
116 [RTN_ANYCAST] = {
117 .error = 0,
118 .scope = RT_SCOPE_LINK,
119 },
120 [RTN_MULTICAST] = {
121 .error = 0,
122 .scope = RT_SCOPE_UNIVERSE,
123 },
124 [RTN_BLACKHOLE] = {
125 .error = -EINVAL,
126 .scope = RT_SCOPE_UNIVERSE,
127 },
128 [RTN_UNREACHABLE] = {
129 .error = -EHOSTUNREACH,
130 .scope = RT_SCOPE_UNIVERSE,
131 },
132 [RTN_PROHIBIT] = {
133 .error = -EACCES,
134 .scope = RT_SCOPE_UNIVERSE,
135 },
136 [RTN_THROW] = {
137 .error = -EAGAIN,
138 .scope = RT_SCOPE_UNIVERSE,
139 },
140 [RTN_NAT] = {
141 .error = -EINVAL,
142 .scope = RT_SCOPE_NOWHERE,
143 },
144 [RTN_XRESOLVE] = {
145 .error = -EINVAL,
146 .scope = RT_SCOPE_NOWHERE,
147 },
148};
149
150static void rt_fibinfo_free(struct rtable __rcu **rtp)
151{
152 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
153
154 if (!rt)
155 return;
156
157 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
158 * because we waited an RCU grace period before calling
159 * free_fib_info_rcu()
160 */
161
162 dst_dev_put(&rt->dst);
163 dst_release_immediate(&rt->dst);
164}
165
166static void free_nh_exceptions(struct fib_nh_common *nhc)
167{
168 struct fnhe_hash_bucket *hash;
169 int i;
170
171 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
172 if (!hash)
173 return;
174 for (i = 0; i < FNHE_HASH_SIZE; i++) {
175 struct fib_nh_exception *fnhe;
176
177 fnhe = rcu_dereference_protected(hash[i].chain, 1);
178 while (fnhe) {
179 struct fib_nh_exception *next;
180
181 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
182
183 rt_fibinfo_free(&fnhe->fnhe_rth_input);
184 rt_fibinfo_free(&fnhe->fnhe_rth_output);
185
186 kfree(fnhe);
187
188 fnhe = next;
189 }
190 }
191 kfree(hash);
192}
193
194static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
195{
196 int cpu;
197
198 if (!rtp)
199 return;
200
201 for_each_possible_cpu(cpu) {
202 struct rtable *rt;
203
204 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
205 if (rt) {
206 dst_dev_put(&rt->dst);
207 dst_release_immediate(&rt->dst);
208 }
209 }
210 free_percpu(rtp);
211}
212
213void fib_nh_common_release(struct fib_nh_common *nhc)
214{
215 netdev_put(nhc->nhc_dev, &nhc->nhc_dev_tracker);
216 lwtstate_put(nhc->nhc_lwtstate);
217 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
218 rt_fibinfo_free(&nhc->nhc_rth_input);
219 free_nh_exceptions(nhc);
220}
221EXPORT_SYMBOL_GPL(fib_nh_common_release);
222
223void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
224{
225#ifdef CONFIG_IP_ROUTE_CLASSID
226 if (fib_nh->nh_tclassid)
227 atomic_dec(&net->ipv4.fib_num_tclassid_users);
228#endif
229 fib_nh_common_release(&fib_nh->nh_common);
230}
231
232/* Release a nexthop info record */
233static void free_fib_info_rcu(struct rcu_head *head)
234{
235 struct fib_info *fi = container_of(head, struct fib_info, rcu);
236
237 if (fi->nh) {
238 nexthop_put(fi->nh);
239 } else {
240 change_nexthops(fi) {
241 fib_nh_release(fi->fib_net, nexthop_nh);
242 } endfor_nexthops(fi);
243 }
244
245 ip_fib_metrics_put(fi->fib_metrics);
246
247 kfree(fi);
248}
249
250void free_fib_info(struct fib_info *fi)
251{
252 if (fi->fib_dead == 0) {
253 pr_warn("Freeing alive fib_info %p\n", fi);
254 return;
255 }
256
257 call_rcu(&fi->rcu, free_fib_info_rcu);
258}
259EXPORT_SYMBOL_GPL(free_fib_info);
260
261void fib_release_info(struct fib_info *fi)
262{
263 spin_lock_bh(&fib_info_lock);
264 if (fi && refcount_dec_and_test(&fi->fib_treeref)) {
265 hlist_del(&fi->fib_hash);
266
267 /* Paired with READ_ONCE() in fib_create_info(). */
268 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
269
270 if (fi->fib_prefsrc)
271 hlist_del(&fi->fib_lhash);
272 if (fi->nh) {
273 list_del(&fi->nh_list);
274 } else {
275 change_nexthops(fi) {
276 if (!nexthop_nh->fib_nh_dev)
277 continue;
278 hlist_del(&nexthop_nh->nh_hash);
279 } endfor_nexthops(fi)
280 }
281 fi->fib_dead = 1;
282 fib_info_put(fi);
283 }
284 spin_unlock_bh(&fib_info_lock);
285}
286
287static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
288{
289 const struct fib_nh *onh;
290
291 if (fi->nh || ofi->nh)
292 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
293
294 if (ofi->fib_nhs == 0)
295 return 0;
296
297 for_nexthops(fi) {
298 onh = fib_info_nh(ofi, nhsel);
299
300 if (nh->fib_nh_oif != onh->fib_nh_oif ||
301 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
302 nh->fib_nh_scope != onh->fib_nh_scope ||
303#ifdef CONFIG_IP_ROUTE_MULTIPATH
304 nh->fib_nh_weight != onh->fib_nh_weight ||
305#endif
306#ifdef CONFIG_IP_ROUTE_CLASSID
307 nh->nh_tclassid != onh->nh_tclassid ||
308#endif
309 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
310 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
311 return -1;
312
313 if (nh->fib_nh_gw_family == AF_INET &&
314 nh->fib_nh_gw4 != onh->fib_nh_gw4)
315 return -1;
316
317 if (nh->fib_nh_gw_family == AF_INET6 &&
318 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
319 return -1;
320 } endfor_nexthops(fi);
321 return 0;
322}
323
324static inline unsigned int fib_devindex_hashfn(unsigned int val)
325{
326 return hash_32(val, DEVINDEX_HASHBITS);
327}
328
329static struct hlist_head *
330fib_info_devhash_bucket(const struct net_device *dev)
331{
332 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
333
334 return &fib_info_devhash[fib_devindex_hashfn(val)];
335}
336
337static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
338 u32 prefsrc, u32 priority)
339{
340 unsigned int val = init_val;
341
342 val ^= (protocol << 8) | scope;
343 val ^= prefsrc;
344 val ^= priority;
345
346 return val;
347}
348
349static unsigned int fib_info_hashfn_result(unsigned int val)
350{
351 unsigned int mask = (fib_info_hash_size - 1);
352
353 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
354}
355
356static inline unsigned int fib_info_hashfn(struct fib_info *fi)
357{
358 unsigned int val;
359
360 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
361 fi->fib_scope, (__force u32)fi->fib_prefsrc,
362 fi->fib_priority);
363
364 if (fi->nh) {
365 val ^= fib_devindex_hashfn(fi->nh->id);
366 } else {
367 for_nexthops(fi) {
368 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
369 } endfor_nexthops(fi)
370 }
371
372 return fib_info_hashfn_result(val);
373}
374
375/* no metrics, only nexthop id */
376static struct fib_info *fib_find_info_nh(struct net *net,
377 const struct fib_config *cfg)
378{
379 struct hlist_head *head;
380 struct fib_info *fi;
381 unsigned int hash;
382
383 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
384 cfg->fc_protocol, cfg->fc_scope,
385 (__force u32)cfg->fc_prefsrc,
386 cfg->fc_priority);
387 hash = fib_info_hashfn_result(hash);
388 head = &fib_info_hash[hash];
389
390 hlist_for_each_entry(fi, head, fib_hash) {
391 if (!net_eq(fi->fib_net, net))
392 continue;
393 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
394 continue;
395 if (cfg->fc_protocol == fi->fib_protocol &&
396 cfg->fc_scope == fi->fib_scope &&
397 cfg->fc_prefsrc == fi->fib_prefsrc &&
398 cfg->fc_priority == fi->fib_priority &&
399 cfg->fc_type == fi->fib_type &&
400 cfg->fc_table == fi->fib_tb_id &&
401 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
402 return fi;
403 }
404
405 return NULL;
406}
407
408static struct fib_info *fib_find_info(struct fib_info *nfi)
409{
410 struct hlist_head *head;
411 struct fib_info *fi;
412 unsigned int hash;
413
414 hash = fib_info_hashfn(nfi);
415 head = &fib_info_hash[hash];
416
417 hlist_for_each_entry(fi, head, fib_hash) {
418 if (!net_eq(fi->fib_net, nfi->fib_net))
419 continue;
420 if (fi->fib_nhs != nfi->fib_nhs)
421 continue;
422 if (nfi->fib_protocol == fi->fib_protocol &&
423 nfi->fib_scope == fi->fib_scope &&
424 nfi->fib_prefsrc == fi->fib_prefsrc &&
425 nfi->fib_priority == fi->fib_priority &&
426 nfi->fib_type == fi->fib_type &&
427 nfi->fib_tb_id == fi->fib_tb_id &&
428 memcmp(nfi->fib_metrics, fi->fib_metrics,
429 sizeof(u32) * RTAX_MAX) == 0 &&
430 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
431 nh_comp(fi, nfi) == 0)
432 return fi;
433 }
434
435 return NULL;
436}
437
438/* Check, that the gateway is already configured.
439 * Used only by redirect accept routine.
440 */
441int ip_fib_check_default(__be32 gw, struct net_device *dev)
442{
443 struct hlist_head *head;
444 struct fib_nh *nh;
445
446 spin_lock(&fib_info_lock);
447
448 head = fib_info_devhash_bucket(dev);
449
450 hlist_for_each_entry(nh, head, nh_hash) {
451 if (nh->fib_nh_dev == dev &&
452 nh->fib_nh_gw4 == gw &&
453 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
454 spin_unlock(&fib_info_lock);
455 return 0;
456 }
457 }
458
459 spin_unlock(&fib_info_lock);
460
461 return -1;
462}
463
464size_t fib_nlmsg_size(struct fib_info *fi)
465{
466 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
467 + nla_total_size(4) /* RTA_TABLE */
468 + nla_total_size(4) /* RTA_DST */
469 + nla_total_size(4) /* RTA_PRIORITY */
470 + nla_total_size(4) /* RTA_PREFSRC */
471 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
472 unsigned int nhs = fib_info_num_path(fi);
473
474 /* space for nested metrics */
475 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
476
477 if (fi->nh)
478 payload += nla_total_size(4); /* RTA_NH_ID */
479
480 if (nhs) {
481 size_t nh_encapsize = 0;
482 /* Also handles the special case nhs == 1 */
483
484 /* each nexthop is packed in an attribute */
485 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
486 unsigned int i;
487
488 /* may contain flow and gateway attribute */
489 nhsize += 2 * nla_total_size(4);
490
491 /* grab encap info */
492 for (i = 0; i < fib_info_num_path(fi); i++) {
493 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
494
495 if (nhc->nhc_lwtstate) {
496 /* RTA_ENCAP_TYPE */
497 nh_encapsize += lwtunnel_get_encap_size(
498 nhc->nhc_lwtstate);
499 /* RTA_ENCAP */
500 nh_encapsize += nla_total_size(2);
501 }
502 }
503
504 /* all nexthops are packed in a nested attribute */
505 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
506
507 }
508
509 return payload;
510}
511
512void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
513 int dst_len, u32 tb_id, const struct nl_info *info,
514 unsigned int nlm_flags)
515{
516 struct fib_rt_info fri;
517 struct sk_buff *skb;
518 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
519 int err = -ENOBUFS;
520
521 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
522 if (!skb)
523 goto errout;
524
525 fri.fi = fa->fa_info;
526 fri.tb_id = tb_id;
527 fri.dst = key;
528 fri.dst_len = dst_len;
529 fri.dscp = fa->fa_dscp;
530 fri.type = fa->fa_type;
531 fri.offload = READ_ONCE(fa->offload);
532 fri.trap = READ_ONCE(fa->trap);
533 fri.offload_failed = READ_ONCE(fa->offload_failed);
534 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
535 if (err < 0) {
536 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
537 WARN_ON(err == -EMSGSIZE);
538 kfree_skb(skb);
539 goto errout;
540 }
541 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
542 info->nlh, GFP_KERNEL);
543 return;
544errout:
545 if (err < 0)
546 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
547}
548
549static int fib_detect_death(struct fib_info *fi, int order,
550 struct fib_info **last_resort, int *last_idx,
551 int dflt)
552{
553 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
554 struct neighbour *n;
555 int state = NUD_NONE;
556
557 if (likely(nhc->nhc_gw_family == AF_INET))
558 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
559 else if (nhc->nhc_gw_family == AF_INET6)
560 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
561 nhc->nhc_dev);
562 else
563 n = NULL;
564
565 if (n) {
566 state = n->nud_state;
567 neigh_release(n);
568 } else {
569 return 0;
570 }
571 if (state == NUD_REACHABLE)
572 return 0;
573 if ((state & NUD_VALID) && order != dflt)
574 return 0;
575 if ((state & NUD_VALID) ||
576 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
577 *last_resort = fi;
578 *last_idx = order;
579 }
580 return 1;
581}
582
583int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
584 struct nlattr *encap, u16 encap_type,
585 void *cfg, gfp_t gfp_flags,
586 struct netlink_ext_ack *extack)
587{
588 int err;
589
590 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
591 gfp_flags);
592 if (!nhc->nhc_pcpu_rth_output)
593 return -ENOMEM;
594
595 if (encap) {
596 struct lwtunnel_state *lwtstate;
597
598 if (encap_type == LWTUNNEL_ENCAP_NONE) {
599 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
600 err = -EINVAL;
601 goto lwt_failure;
602 }
603 err = lwtunnel_build_state(net, encap_type, encap,
604 nhc->nhc_family, cfg, &lwtstate,
605 extack);
606 if (err)
607 goto lwt_failure;
608
609 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
610 }
611
612 return 0;
613
614lwt_failure:
615 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
616 nhc->nhc_pcpu_rth_output = NULL;
617 return err;
618}
619EXPORT_SYMBOL_GPL(fib_nh_common_init);
620
621int fib_nh_init(struct net *net, struct fib_nh *nh,
622 struct fib_config *cfg, int nh_weight,
623 struct netlink_ext_ack *extack)
624{
625 int err;
626
627 nh->fib_nh_family = AF_INET;
628
629 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
630 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
631 if (err)
632 return err;
633
634 nh->fib_nh_oif = cfg->fc_oif;
635 nh->fib_nh_gw_family = cfg->fc_gw_family;
636 if (cfg->fc_gw_family == AF_INET)
637 nh->fib_nh_gw4 = cfg->fc_gw4;
638 else if (cfg->fc_gw_family == AF_INET6)
639 nh->fib_nh_gw6 = cfg->fc_gw6;
640
641 nh->fib_nh_flags = cfg->fc_flags;
642
643#ifdef CONFIG_IP_ROUTE_CLASSID
644 nh->nh_tclassid = cfg->fc_flow;
645 if (nh->nh_tclassid)
646 atomic_inc(&net->ipv4.fib_num_tclassid_users);
647#endif
648#ifdef CONFIG_IP_ROUTE_MULTIPATH
649 nh->fib_nh_weight = nh_weight;
650#endif
651 return 0;
652}
653
654#ifdef CONFIG_IP_ROUTE_MULTIPATH
655
656static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
657 struct netlink_ext_ack *extack)
658{
659 int nhs = 0;
660
661 while (rtnh_ok(rtnh, remaining)) {
662 nhs++;
663 rtnh = rtnh_next(rtnh, &remaining);
664 }
665
666 /* leftover implies invalid nexthop configuration, discard it */
667 if (remaining > 0) {
668 NL_SET_ERR_MSG(extack,
669 "Invalid nexthop configuration - extra data after nexthops");
670 nhs = 0;
671 }
672
673 return nhs;
674}
675
676static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
677 struct netlink_ext_ack *extack)
678{
679 if (nla_len(nla) < sizeof(*gw)) {
680 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
681 return -EINVAL;
682 }
683
684 *gw = nla_get_in_addr(nla);
685
686 return 0;
687}
688
689/* only called when fib_nh is integrated into fib_info */
690static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
691 int remaining, struct fib_config *cfg,
692 struct netlink_ext_ack *extack)
693{
694 struct net *net = fi->fib_net;
695 struct fib_config fib_cfg;
696 struct fib_nh *nh;
697 int ret;
698
699 change_nexthops(fi) {
700 int attrlen;
701
702 memset(&fib_cfg, 0, sizeof(fib_cfg));
703
704 if (!rtnh_ok(rtnh, remaining)) {
705 NL_SET_ERR_MSG(extack,
706 "Invalid nexthop configuration - extra data after nexthop");
707 return -EINVAL;
708 }
709
710 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
711 NL_SET_ERR_MSG(extack,
712 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
713 return -EINVAL;
714 }
715
716 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
717 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
718
719 attrlen = rtnh_attrlen(rtnh);
720 if (attrlen > 0) {
721 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
722
723 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
724 nlav = nla_find(attrs, attrlen, RTA_VIA);
725 if (nla && nlav) {
726 NL_SET_ERR_MSG(extack,
727 "Nexthop configuration can not contain both GATEWAY and VIA");
728 return -EINVAL;
729 }
730 if (nla) {
731 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
732 extack);
733 if (ret)
734 goto errout;
735
736 if (fib_cfg.fc_gw4)
737 fib_cfg.fc_gw_family = AF_INET;
738 } else if (nlav) {
739 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
740 if (ret)
741 goto errout;
742 }
743
744 nla = nla_find(attrs, attrlen, RTA_FLOW);
745 if (nla) {
746 if (nla_len(nla) < sizeof(u32)) {
747 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
748 return -EINVAL;
749 }
750 fib_cfg.fc_flow = nla_get_u32(nla);
751 }
752
753 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
754 /* RTA_ENCAP_TYPE length checked in
755 * lwtunnel_valid_encap_type_attr
756 */
757 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
758 if (nla)
759 fib_cfg.fc_encap_type = nla_get_u16(nla);
760 }
761
762 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
763 rtnh->rtnh_hops + 1, extack);
764 if (ret)
765 goto errout;
766
767 rtnh = rtnh_next(rtnh, &remaining);
768 } endfor_nexthops(fi);
769
770 ret = -EINVAL;
771 nh = fib_info_nh(fi, 0);
772 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
773 NL_SET_ERR_MSG(extack,
774 "Nexthop device index does not match RTA_OIF");
775 goto errout;
776 }
777 if (cfg->fc_gw_family) {
778 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
779 (cfg->fc_gw_family == AF_INET &&
780 nh->fib_nh_gw4 != cfg->fc_gw4) ||
781 (cfg->fc_gw_family == AF_INET6 &&
782 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
783 NL_SET_ERR_MSG(extack,
784 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
785 goto errout;
786 }
787 }
788#ifdef CONFIG_IP_ROUTE_CLASSID
789 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
790 NL_SET_ERR_MSG(extack,
791 "Nexthop class id does not match RTA_FLOW");
792 goto errout;
793 }
794#endif
795 ret = 0;
796errout:
797 return ret;
798}
799
800/* only called when fib_nh is integrated into fib_info */
801static void fib_rebalance(struct fib_info *fi)
802{
803 int total;
804 int w;
805
806 if (fib_info_num_path(fi) < 2)
807 return;
808
809 total = 0;
810 for_nexthops(fi) {
811 if (nh->fib_nh_flags & RTNH_F_DEAD)
812 continue;
813
814 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
815 nh->fib_nh_flags & RTNH_F_LINKDOWN)
816 continue;
817
818 total += nh->fib_nh_weight;
819 } endfor_nexthops(fi);
820
821 w = 0;
822 change_nexthops(fi) {
823 int upper_bound;
824
825 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
826 upper_bound = -1;
827 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
828 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
829 upper_bound = -1;
830 } else {
831 w += nexthop_nh->fib_nh_weight;
832 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
833 total) - 1;
834 }
835
836 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
837 } endfor_nexthops(fi);
838}
839#else /* CONFIG_IP_ROUTE_MULTIPATH */
840
841static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
842 int remaining, struct fib_config *cfg,
843 struct netlink_ext_ack *extack)
844{
845 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
846
847 return -EINVAL;
848}
849
850#define fib_rebalance(fi) do { } while (0)
851
852#endif /* CONFIG_IP_ROUTE_MULTIPATH */
853
854static int fib_encap_match(struct net *net, u16 encap_type,
855 struct nlattr *encap,
856 const struct fib_nh *nh,
857 const struct fib_config *cfg,
858 struct netlink_ext_ack *extack)
859{
860 struct lwtunnel_state *lwtstate;
861 int ret, result = 0;
862
863 if (encap_type == LWTUNNEL_ENCAP_NONE)
864 return 0;
865
866 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
867 cfg, &lwtstate, extack);
868 if (!ret) {
869 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
870 lwtstate_free(lwtstate);
871 }
872
873 return result;
874}
875
876int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
877 struct netlink_ext_ack *extack)
878{
879#ifdef CONFIG_IP_ROUTE_MULTIPATH
880 struct rtnexthop *rtnh;
881 int remaining;
882#endif
883
884 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
885 return 1;
886
887 if (cfg->fc_nh_id) {
888 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
889 return 0;
890 return 1;
891 }
892
893 if (fi->nh) {
894 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
895 return 1;
896 return 0;
897 }
898
899 if (cfg->fc_oif || cfg->fc_gw_family) {
900 struct fib_nh *nh;
901
902 nh = fib_info_nh(fi, 0);
903 if (cfg->fc_encap) {
904 if (fib_encap_match(net, cfg->fc_encap_type,
905 cfg->fc_encap, nh, cfg, extack))
906 return 1;
907 }
908#ifdef CONFIG_IP_ROUTE_CLASSID
909 if (cfg->fc_flow &&
910 cfg->fc_flow != nh->nh_tclassid)
911 return 1;
912#endif
913 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
914 (cfg->fc_gw_family &&
915 cfg->fc_gw_family != nh->fib_nh_gw_family))
916 return 1;
917
918 if (cfg->fc_gw_family == AF_INET &&
919 cfg->fc_gw4 != nh->fib_nh_gw4)
920 return 1;
921
922 if (cfg->fc_gw_family == AF_INET6 &&
923 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
924 return 1;
925
926 return 0;
927 }
928
929#ifdef CONFIG_IP_ROUTE_MULTIPATH
930 if (!cfg->fc_mp)
931 return 0;
932
933 rtnh = cfg->fc_mp;
934 remaining = cfg->fc_mp_len;
935
936 for_nexthops(fi) {
937 int attrlen;
938
939 if (!rtnh_ok(rtnh, remaining))
940 return -EINVAL;
941
942 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
943 return 1;
944
945 attrlen = rtnh_attrlen(rtnh);
946 if (attrlen > 0) {
947 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
948 int err;
949
950 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
951 nlav = nla_find(attrs, attrlen, RTA_VIA);
952 if (nla && nlav) {
953 NL_SET_ERR_MSG(extack,
954 "Nexthop configuration can not contain both GATEWAY and VIA");
955 return -EINVAL;
956 }
957
958 if (nla) {
959 __be32 gw;
960
961 err = fib_gw_from_attr(&gw, nla, extack);
962 if (err)
963 return err;
964
965 if (nh->fib_nh_gw_family != AF_INET ||
966 gw != nh->fib_nh_gw4)
967 return 1;
968 } else if (nlav) {
969 struct fib_config cfg2;
970
971 err = fib_gw_from_via(&cfg2, nlav, extack);
972 if (err)
973 return err;
974
975 switch (nh->fib_nh_gw_family) {
976 case AF_INET:
977 if (cfg2.fc_gw_family != AF_INET ||
978 cfg2.fc_gw4 != nh->fib_nh_gw4)
979 return 1;
980 break;
981 case AF_INET6:
982 if (cfg2.fc_gw_family != AF_INET6 ||
983 ipv6_addr_cmp(&cfg2.fc_gw6,
984 &nh->fib_nh_gw6))
985 return 1;
986 break;
987 }
988 }
989
990#ifdef CONFIG_IP_ROUTE_CLASSID
991 nla = nla_find(attrs, attrlen, RTA_FLOW);
992 if (nla) {
993 if (nla_len(nla) < sizeof(u32)) {
994 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
995 return -EINVAL;
996 }
997 if (nla_get_u32(nla) != nh->nh_tclassid)
998 return 1;
999 }
1000#endif
1001 }
1002
1003 rtnh = rtnh_next(rtnh, &remaining);
1004 } endfor_nexthops(fi);
1005#endif
1006 return 0;
1007}
1008
1009bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1010{
1011 struct nlattr *nla;
1012 int remaining;
1013
1014 if (!cfg->fc_mx)
1015 return true;
1016
1017 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1018 int type = nla_type(nla);
1019 u32 fi_val, val;
1020
1021 if (!type)
1022 continue;
1023 if (type > RTAX_MAX)
1024 return false;
1025
1026 type = array_index_nospec(type, RTAX_MAX + 1);
1027 if (type == RTAX_CC_ALGO) {
1028 char tmp[TCP_CA_NAME_MAX];
1029 bool ecn_ca = false;
1030
1031 nla_strscpy(tmp, nla, sizeof(tmp));
1032 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1033 } else {
1034 if (nla_len(nla) != sizeof(u32))
1035 return false;
1036 val = nla_get_u32(nla);
1037 }
1038
1039 fi_val = fi->fib_metrics->metrics[type - 1];
1040 if (type == RTAX_FEATURES)
1041 fi_val &= ~DST_FEATURE_ECN_CA;
1042
1043 if (fi_val != val)
1044 return false;
1045 }
1046
1047 return true;
1048}
1049
1050static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1051 u32 table, struct netlink_ext_ack *extack)
1052{
1053 struct fib6_config cfg = {
1054 .fc_table = table,
1055 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1056 .fc_ifindex = nh->fib_nh_oif,
1057 .fc_gateway = nh->fib_nh_gw6,
1058 };
1059 struct fib6_nh fib6_nh = {};
1060 int err;
1061
1062 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1063 if (!err) {
1064 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1065 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1066 GFP_KERNEL);
1067 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1068 nh->fib_nh_scope = RT_SCOPE_LINK;
1069
1070 ipv6_stub->fib6_nh_release(&fib6_nh);
1071 }
1072
1073 return err;
1074}
1075
1076/*
1077 * Picture
1078 * -------
1079 *
1080 * Semantics of nexthop is very messy by historical reasons.
1081 * We have to take into account, that:
1082 * a) gateway can be actually local interface address,
1083 * so that gatewayed route is direct.
1084 * b) gateway must be on-link address, possibly
1085 * described not by an ifaddr, but also by a direct route.
1086 * c) If both gateway and interface are specified, they should not
1087 * contradict.
1088 * d) If we use tunnel routes, gateway could be not on-link.
1089 *
1090 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1091 * results in pretty ugly and hairy code with obscure logic.
1092 *
1093 * I chose to generalized it instead, so that the size
1094 * of code does not increase practically, but it becomes
1095 * much more general.
1096 * Every prefix is assigned a "scope" value: "host" is local address,
1097 * "link" is direct route,
1098 * [ ... "site" ... "interior" ... ]
1099 * and "universe" is true gateway route with global meaning.
1100 *
1101 * Every prefix refers to a set of "nexthop"s (gw, oif),
1102 * where gw must have narrower scope. This recursion stops
1103 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1104 * which means that gw is forced to be on link.
1105 *
1106 * Code is still hairy, but now it is apparently logically
1107 * consistent and very flexible. F.e. as by-product it allows
1108 * to co-exists in peace independent exterior and interior
1109 * routing processes.
1110 *
1111 * Normally it looks as following.
1112 *
1113 * {universe prefix} -> (gw, oif) [scope link]
1114 * |
1115 * |-> {link prefix} -> (gw, oif) [scope local]
1116 * |
1117 * |-> {local prefix} (terminal node)
1118 */
1119static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1120 u8 scope, struct netlink_ext_ack *extack)
1121{
1122 struct net_device *dev;
1123 struct fib_result res;
1124 int err = 0;
1125
1126 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1127 unsigned int addr_type;
1128
1129 if (scope >= RT_SCOPE_LINK) {
1130 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1131 return -EINVAL;
1132 }
1133 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1134 if (!dev) {
1135 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1136 return -ENODEV;
1137 }
1138 if (!(dev->flags & IFF_UP)) {
1139 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1140 return -ENETDOWN;
1141 }
1142 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1143 if (addr_type != RTN_UNICAST) {
1144 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1145 return -EINVAL;
1146 }
1147 if (!netif_carrier_ok(dev))
1148 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1149 nh->fib_nh_dev = dev;
1150 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1151 nh->fib_nh_scope = RT_SCOPE_LINK;
1152 return 0;
1153 }
1154 rcu_read_lock();
1155 {
1156 struct fib_table *tbl = NULL;
1157 struct flowi4 fl4 = {
1158 .daddr = nh->fib_nh_gw4,
1159 .flowi4_scope = scope + 1,
1160 .flowi4_oif = nh->fib_nh_oif,
1161 .flowi4_iif = LOOPBACK_IFINDEX,
1162 };
1163
1164 /* It is not necessary, but requires a bit of thinking */
1165 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1166 fl4.flowi4_scope = RT_SCOPE_LINK;
1167
1168 if (table && table != RT_TABLE_MAIN)
1169 tbl = fib_get_table(net, table);
1170
1171 if (tbl)
1172 err = fib_table_lookup(tbl, &fl4, &res,
1173 FIB_LOOKUP_IGNORE_LINKSTATE |
1174 FIB_LOOKUP_NOREF);
1175
1176 /* on error or if no table given do full lookup. This
1177 * is needed for example when nexthops are in the local
1178 * table rather than the given table
1179 */
1180 if (!tbl || err) {
1181 err = fib_lookup(net, &fl4, &res,
1182 FIB_LOOKUP_IGNORE_LINKSTATE);
1183 }
1184
1185 if (err) {
1186 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1187 goto out;
1188 }
1189 }
1190
1191 err = -EINVAL;
1192 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1193 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1194 goto out;
1195 }
1196 nh->fib_nh_scope = res.scope;
1197 nh->fib_nh_oif = FIB_RES_OIF(res);
1198 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1199 if (!dev) {
1200 NL_SET_ERR_MSG(extack,
1201 "No egress device for nexthop gateway");
1202 goto out;
1203 }
1204 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1205 if (!netif_carrier_ok(dev))
1206 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1207 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1208out:
1209 rcu_read_unlock();
1210 return err;
1211}
1212
1213static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1214 struct netlink_ext_ack *extack)
1215{
1216 struct in_device *in_dev;
1217 int err;
1218
1219 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1220 NL_SET_ERR_MSG(extack,
1221 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1222 return -EINVAL;
1223 }
1224
1225 rcu_read_lock();
1226
1227 err = -ENODEV;
1228 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1229 if (!in_dev)
1230 goto out;
1231 err = -ENETDOWN;
1232 if (!(in_dev->dev->flags & IFF_UP)) {
1233 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1234 goto out;
1235 }
1236
1237 nh->fib_nh_dev = in_dev->dev;
1238 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1239 nh->fib_nh_scope = RT_SCOPE_HOST;
1240 if (!netif_carrier_ok(nh->fib_nh_dev))
1241 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1242 err = 0;
1243out:
1244 rcu_read_unlock();
1245 return err;
1246}
1247
1248int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1249 struct netlink_ext_ack *extack)
1250{
1251 int err;
1252
1253 if (nh->fib_nh_gw_family == AF_INET)
1254 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1255 else if (nh->fib_nh_gw_family == AF_INET6)
1256 err = fib_check_nh_v6_gw(net, nh, table, extack);
1257 else
1258 err = fib_check_nh_nongw(net, nh, extack);
1259
1260 return err;
1261}
1262
1263static struct hlist_head *
1264fib_info_laddrhash_bucket(const struct net *net, __be32 val)
1265{
1266 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val,
1267 fib_info_hash_bits);
1268
1269 return &fib_info_laddrhash[slot];
1270}
1271
1272static void fib_info_hash_move(struct hlist_head *new_info_hash,
1273 struct hlist_head *new_laddrhash,
1274 unsigned int new_size)
1275{
1276 struct hlist_head *old_info_hash, *old_laddrhash;
1277 unsigned int old_size = fib_info_hash_size;
1278 unsigned int i;
1279
1280 spin_lock_bh(&fib_info_lock);
1281 old_info_hash = fib_info_hash;
1282 old_laddrhash = fib_info_laddrhash;
1283 fib_info_hash_size = new_size;
1284 fib_info_hash_bits = ilog2(new_size);
1285
1286 for (i = 0; i < old_size; i++) {
1287 struct hlist_head *head = &fib_info_hash[i];
1288 struct hlist_node *n;
1289 struct fib_info *fi;
1290
1291 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1292 struct hlist_head *dest;
1293 unsigned int new_hash;
1294
1295 new_hash = fib_info_hashfn(fi);
1296 dest = &new_info_hash[new_hash];
1297 hlist_add_head(&fi->fib_hash, dest);
1298 }
1299 }
1300 fib_info_hash = new_info_hash;
1301
1302 fib_info_laddrhash = new_laddrhash;
1303 for (i = 0; i < old_size; i++) {
1304 struct hlist_head *lhead = &old_laddrhash[i];
1305 struct hlist_node *n;
1306 struct fib_info *fi;
1307
1308 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1309 struct hlist_head *ldest;
1310
1311 ldest = fib_info_laddrhash_bucket(fi->fib_net,
1312 fi->fib_prefsrc);
1313 hlist_add_head(&fi->fib_lhash, ldest);
1314 }
1315 }
1316
1317 spin_unlock_bh(&fib_info_lock);
1318
1319 kvfree(old_info_hash);
1320 kvfree(old_laddrhash);
1321}
1322
1323__be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1324 unsigned char scope)
1325{
1326 struct fib_nh *nh;
1327
1328 if (nhc->nhc_family != AF_INET)
1329 return inet_select_addr(nhc->nhc_dev, 0, scope);
1330
1331 nh = container_of(nhc, struct fib_nh, nh_common);
1332 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1333 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1334
1335 return nh->nh_saddr;
1336}
1337
1338__be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1339{
1340 struct fib_nh_common *nhc = res->nhc;
1341
1342 if (res->fi->fib_prefsrc)
1343 return res->fi->fib_prefsrc;
1344
1345 if (nhc->nhc_family == AF_INET) {
1346 struct fib_nh *nh;
1347
1348 nh = container_of(nhc, struct fib_nh, nh_common);
1349 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1350 return nh->nh_saddr;
1351 }
1352
1353 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1354}
1355
1356static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1357{
1358 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1359 fib_prefsrc != cfg->fc_dst) {
1360 u32 tb_id = cfg->fc_table;
1361 int rc;
1362
1363 if (tb_id == RT_TABLE_MAIN)
1364 tb_id = RT_TABLE_LOCAL;
1365
1366 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1367 fib_prefsrc, tb_id);
1368
1369 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1370 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1371 fib_prefsrc, RT_TABLE_LOCAL);
1372 }
1373
1374 if (rc != RTN_LOCAL)
1375 return false;
1376 }
1377 return true;
1378}
1379
1380struct fib_info *fib_create_info(struct fib_config *cfg,
1381 struct netlink_ext_ack *extack)
1382{
1383 int err;
1384 struct fib_info *fi = NULL;
1385 struct nexthop *nh = NULL;
1386 struct fib_info *ofi;
1387 int nhs = 1;
1388 struct net *net = cfg->fc_nlinfo.nl_net;
1389
1390 if (cfg->fc_type > RTN_MAX)
1391 goto err_inval;
1392
1393 /* Fast check to catch the most weird cases */
1394 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1395 NL_SET_ERR_MSG(extack, "Invalid scope");
1396 goto err_inval;
1397 }
1398
1399 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1400 NL_SET_ERR_MSG(extack,
1401 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1402 goto err_inval;
1403 }
1404
1405 if (cfg->fc_nh_id) {
1406 if (!cfg->fc_mx) {
1407 fi = fib_find_info_nh(net, cfg);
1408 if (fi) {
1409 refcount_inc(&fi->fib_treeref);
1410 return fi;
1411 }
1412 }
1413
1414 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1415 if (!nh) {
1416 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1417 goto err_inval;
1418 }
1419 nhs = 0;
1420 }
1421
1422#ifdef CONFIG_IP_ROUTE_MULTIPATH
1423 if (cfg->fc_mp) {
1424 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1425 if (nhs == 0)
1426 goto err_inval;
1427 }
1428#endif
1429
1430 err = -ENOBUFS;
1431
1432 /* Paired with WRITE_ONCE() in fib_release_info() */
1433 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) {
1434 unsigned int new_size = fib_info_hash_size << 1;
1435 struct hlist_head *new_info_hash;
1436 struct hlist_head *new_laddrhash;
1437 size_t bytes;
1438
1439 if (!new_size)
1440 new_size = 16;
1441 bytes = (size_t)new_size * sizeof(struct hlist_head *);
1442 new_info_hash = kvzalloc(bytes, GFP_KERNEL);
1443 new_laddrhash = kvzalloc(bytes, GFP_KERNEL);
1444 if (!new_info_hash || !new_laddrhash) {
1445 kvfree(new_info_hash);
1446 kvfree(new_laddrhash);
1447 } else {
1448 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1449 }
1450 if (!fib_info_hash_size)
1451 goto failure;
1452 }
1453
1454 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1455 if (!fi)
1456 goto failure;
1457 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1458 cfg->fc_mx_len, extack);
1459 if (IS_ERR(fi->fib_metrics)) {
1460 err = PTR_ERR(fi->fib_metrics);
1461 kfree(fi);
1462 return ERR_PTR(err);
1463 }
1464
1465 fi->fib_net = net;
1466 fi->fib_protocol = cfg->fc_protocol;
1467 fi->fib_scope = cfg->fc_scope;
1468 fi->fib_flags = cfg->fc_flags;
1469 fi->fib_priority = cfg->fc_priority;
1470 fi->fib_prefsrc = cfg->fc_prefsrc;
1471 fi->fib_type = cfg->fc_type;
1472 fi->fib_tb_id = cfg->fc_table;
1473
1474 fi->fib_nhs = nhs;
1475 if (nh) {
1476 if (!nexthop_get(nh)) {
1477 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1478 err = -EINVAL;
1479 } else {
1480 err = 0;
1481 fi->nh = nh;
1482 }
1483 } else {
1484 change_nexthops(fi) {
1485 nexthop_nh->nh_parent = fi;
1486 } endfor_nexthops(fi)
1487
1488 if (cfg->fc_mp)
1489 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1490 extack);
1491 else
1492 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1493 }
1494
1495 if (err != 0)
1496 goto failure;
1497
1498 if (fib_props[cfg->fc_type].error) {
1499 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1500 NL_SET_ERR_MSG(extack,
1501 "Gateway, device and multipath can not be specified for this route type");
1502 goto err_inval;
1503 }
1504 goto link_it;
1505 } else {
1506 switch (cfg->fc_type) {
1507 case RTN_UNICAST:
1508 case RTN_LOCAL:
1509 case RTN_BROADCAST:
1510 case RTN_ANYCAST:
1511 case RTN_MULTICAST:
1512 break;
1513 default:
1514 NL_SET_ERR_MSG(extack, "Invalid route type");
1515 goto err_inval;
1516 }
1517 }
1518
1519 if (cfg->fc_scope > RT_SCOPE_HOST) {
1520 NL_SET_ERR_MSG(extack, "Invalid scope");
1521 goto err_inval;
1522 }
1523
1524 if (fi->nh) {
1525 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1526 if (err)
1527 goto failure;
1528 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1529 struct fib_nh *nh = fi->fib_nh;
1530
1531 /* Local address is added. */
1532 if (nhs != 1) {
1533 NL_SET_ERR_MSG(extack,
1534 "Route with host scope can not have multiple nexthops");
1535 goto err_inval;
1536 }
1537 if (nh->fib_nh_gw_family) {
1538 NL_SET_ERR_MSG(extack,
1539 "Route with host scope can not have a gateway");
1540 goto err_inval;
1541 }
1542 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1543 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1544 err = -ENODEV;
1545 if (!nh->fib_nh_dev)
1546 goto failure;
1547 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1548 GFP_KERNEL);
1549 } else {
1550 int linkdown = 0;
1551
1552 change_nexthops(fi) {
1553 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1554 cfg->fc_table, cfg->fc_scope,
1555 extack);
1556 if (err != 0)
1557 goto failure;
1558 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1559 linkdown++;
1560 } endfor_nexthops(fi)
1561 if (linkdown == fi->fib_nhs)
1562 fi->fib_flags |= RTNH_F_LINKDOWN;
1563 }
1564
1565 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1566 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1567 goto err_inval;
1568 }
1569
1570 if (!fi->nh) {
1571 change_nexthops(fi) {
1572 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1573 fi->fib_scope);
1574 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1575 fi->fib_nh_is_v6 = true;
1576 } endfor_nexthops(fi)
1577
1578 fib_rebalance(fi);
1579 }
1580
1581link_it:
1582 ofi = fib_find_info(fi);
1583 if (ofi) {
1584 fi->fib_dead = 1;
1585 free_fib_info(fi);
1586 refcount_inc(&ofi->fib_treeref);
1587 return ofi;
1588 }
1589
1590 refcount_set(&fi->fib_treeref, 1);
1591 refcount_set(&fi->fib_clntref, 1);
1592 spin_lock_bh(&fib_info_lock);
1593 fib_info_cnt++;
1594 hlist_add_head(&fi->fib_hash,
1595 &fib_info_hash[fib_info_hashfn(fi)]);
1596 if (fi->fib_prefsrc) {
1597 struct hlist_head *head;
1598
1599 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc);
1600 hlist_add_head(&fi->fib_lhash, head);
1601 }
1602 if (fi->nh) {
1603 list_add(&fi->nh_list, &nh->fi_list);
1604 } else {
1605 change_nexthops(fi) {
1606 struct hlist_head *head;
1607
1608 if (!nexthop_nh->fib_nh_dev)
1609 continue;
1610 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
1611 hlist_add_head(&nexthop_nh->nh_hash, head);
1612 } endfor_nexthops(fi)
1613 }
1614 spin_unlock_bh(&fib_info_lock);
1615 return fi;
1616
1617err_inval:
1618 err = -EINVAL;
1619
1620failure:
1621 if (fi) {
1622 fi->fib_dead = 1;
1623 free_fib_info(fi);
1624 }
1625
1626 return ERR_PTR(err);
1627}
1628
1629int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1630 u8 rt_family, unsigned char *flags, bool skip_oif)
1631{
1632 if (nhc->nhc_flags & RTNH_F_DEAD)
1633 *flags |= RTNH_F_DEAD;
1634
1635 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1636 *flags |= RTNH_F_LINKDOWN;
1637
1638 rcu_read_lock();
1639 switch (nhc->nhc_family) {
1640 case AF_INET:
1641 if (ip_ignore_linkdown(nhc->nhc_dev))
1642 *flags |= RTNH_F_DEAD;
1643 break;
1644 case AF_INET6:
1645 if (ip6_ignore_linkdown(nhc->nhc_dev))
1646 *flags |= RTNH_F_DEAD;
1647 break;
1648 }
1649 rcu_read_unlock();
1650 }
1651
1652 switch (nhc->nhc_gw_family) {
1653 case AF_INET:
1654 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1655 goto nla_put_failure;
1656 break;
1657 case AF_INET6:
1658 /* if gateway family does not match nexthop family
1659 * gateway is encoded as RTA_VIA
1660 */
1661 if (rt_family != nhc->nhc_gw_family) {
1662 int alen = sizeof(struct in6_addr);
1663 struct nlattr *nla;
1664 struct rtvia *via;
1665
1666 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1667 if (!nla)
1668 goto nla_put_failure;
1669
1670 via = nla_data(nla);
1671 via->rtvia_family = AF_INET6;
1672 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1673 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1674 &nhc->nhc_gw.ipv6) < 0) {
1675 goto nla_put_failure;
1676 }
1677 break;
1678 }
1679
1680 *flags |= (nhc->nhc_flags &
1681 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1682
1683 if (!skip_oif && nhc->nhc_dev &&
1684 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1685 goto nla_put_failure;
1686
1687 if (nhc->nhc_lwtstate &&
1688 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1689 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1690 goto nla_put_failure;
1691
1692 return 0;
1693
1694nla_put_failure:
1695 return -EMSGSIZE;
1696}
1697EXPORT_SYMBOL_GPL(fib_nexthop_info);
1698
1699#if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1700int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1701 int nh_weight, u8 rt_family, u32 nh_tclassid)
1702{
1703 const struct net_device *dev = nhc->nhc_dev;
1704 struct rtnexthop *rtnh;
1705 unsigned char flags = 0;
1706
1707 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1708 if (!rtnh)
1709 goto nla_put_failure;
1710
1711 rtnh->rtnh_hops = nh_weight - 1;
1712 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1713
1714 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1715 goto nla_put_failure;
1716
1717 rtnh->rtnh_flags = flags;
1718
1719 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1720 goto nla_put_failure;
1721
1722 /* length of rtnetlink header + attributes */
1723 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1724
1725 return 0;
1726
1727nla_put_failure:
1728 return -EMSGSIZE;
1729}
1730EXPORT_SYMBOL_GPL(fib_add_nexthop);
1731#endif
1732
1733#ifdef CONFIG_IP_ROUTE_MULTIPATH
1734static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1735{
1736 struct nlattr *mp;
1737
1738 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1739 if (!mp)
1740 goto nla_put_failure;
1741
1742 if (unlikely(fi->nh)) {
1743 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1744 goto nla_put_failure;
1745 goto mp_end;
1746 }
1747
1748 for_nexthops(fi) {
1749 u32 nh_tclassid = 0;
1750#ifdef CONFIG_IP_ROUTE_CLASSID
1751 nh_tclassid = nh->nh_tclassid;
1752#endif
1753 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1754 AF_INET, nh_tclassid) < 0)
1755 goto nla_put_failure;
1756 } endfor_nexthops(fi);
1757
1758mp_end:
1759 nla_nest_end(skb, mp);
1760
1761 return 0;
1762
1763nla_put_failure:
1764 return -EMSGSIZE;
1765}
1766#else
1767static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1768{
1769 return 0;
1770}
1771#endif
1772
1773int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1774 const struct fib_rt_info *fri, unsigned int flags)
1775{
1776 unsigned int nhs = fib_info_num_path(fri->fi);
1777 struct fib_info *fi = fri->fi;
1778 u32 tb_id = fri->tb_id;
1779 struct nlmsghdr *nlh;
1780 struct rtmsg *rtm;
1781
1782 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1783 if (!nlh)
1784 return -EMSGSIZE;
1785
1786 rtm = nlmsg_data(nlh);
1787 rtm->rtm_family = AF_INET;
1788 rtm->rtm_dst_len = fri->dst_len;
1789 rtm->rtm_src_len = 0;
1790 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp);
1791 if (tb_id < 256)
1792 rtm->rtm_table = tb_id;
1793 else
1794 rtm->rtm_table = RT_TABLE_COMPAT;
1795 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1796 goto nla_put_failure;
1797 rtm->rtm_type = fri->type;
1798 rtm->rtm_flags = fi->fib_flags;
1799 rtm->rtm_scope = fi->fib_scope;
1800 rtm->rtm_protocol = fi->fib_protocol;
1801
1802 if (rtm->rtm_dst_len &&
1803 nla_put_in_addr(skb, RTA_DST, fri->dst))
1804 goto nla_put_failure;
1805 if (fi->fib_priority &&
1806 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1807 goto nla_put_failure;
1808 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1809 goto nla_put_failure;
1810
1811 if (fi->fib_prefsrc &&
1812 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1813 goto nla_put_failure;
1814
1815 if (fi->nh) {
1816 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1817 goto nla_put_failure;
1818 if (nexthop_is_blackhole(fi->nh))
1819 rtm->rtm_type = RTN_BLACKHOLE;
1820 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
1821 goto offload;
1822 }
1823
1824 if (nhs == 1) {
1825 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1826 unsigned char flags = 0;
1827
1828 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1829 goto nla_put_failure;
1830
1831 rtm->rtm_flags = flags;
1832#ifdef CONFIG_IP_ROUTE_CLASSID
1833 if (nhc->nhc_family == AF_INET) {
1834 struct fib_nh *nh;
1835
1836 nh = container_of(nhc, struct fib_nh, nh_common);
1837 if (nh->nh_tclassid &&
1838 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1839 goto nla_put_failure;
1840 }
1841#endif
1842 } else {
1843 if (fib_add_multipath(skb, fi) < 0)
1844 goto nla_put_failure;
1845 }
1846
1847offload:
1848 if (fri->offload)
1849 rtm->rtm_flags |= RTM_F_OFFLOAD;
1850 if (fri->trap)
1851 rtm->rtm_flags |= RTM_F_TRAP;
1852 if (fri->offload_failed)
1853 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1854
1855 nlmsg_end(skb, nlh);
1856 return 0;
1857
1858nla_put_failure:
1859 nlmsg_cancel(skb, nlh);
1860 return -EMSGSIZE;
1861}
1862
1863/*
1864 * Update FIB if:
1865 * - local address disappeared -> we must delete all the entries
1866 * referring to it.
1867 * - device went down -> we must shutdown all nexthops going via it.
1868 */
1869int fib_sync_down_addr(struct net_device *dev, __be32 local)
1870{
1871 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1872 struct net *net = dev_net(dev);
1873 struct hlist_head *head;
1874 struct fib_info *fi;
1875 int ret = 0;
1876
1877 if (!fib_info_laddrhash || local == 0)
1878 return 0;
1879
1880 head = fib_info_laddrhash_bucket(net, local);
1881 hlist_for_each_entry(fi, head, fib_lhash) {
1882 if (!net_eq(fi->fib_net, net) ||
1883 fi->fib_tb_id != tb_id)
1884 continue;
1885 if (fi->fib_prefsrc == local) {
1886 fi->fib_flags |= RTNH_F_DEAD;
1887 ret++;
1888 }
1889 }
1890 return ret;
1891}
1892
1893static int call_fib_nh_notifiers(struct fib_nh *nh,
1894 enum fib_event_type event_type)
1895{
1896 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1897 struct fib_nh_notifier_info info = {
1898 .fib_nh = nh,
1899 };
1900
1901 switch (event_type) {
1902 case FIB_EVENT_NH_ADD:
1903 if (nh->fib_nh_flags & RTNH_F_DEAD)
1904 break;
1905 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1906 break;
1907 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1908 &info.info);
1909 case FIB_EVENT_NH_DEL:
1910 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1911 (nh->fib_nh_flags & RTNH_F_DEAD))
1912 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1913 event_type, &info.info);
1914 break;
1915 default:
1916 break;
1917 }
1918
1919 return NOTIFY_DONE;
1920}
1921
1922/* Update the PMTU of exceptions when:
1923 * - the new MTU of the first hop becomes smaller than the PMTU
1924 * - the old MTU was the same as the PMTU, and it limited discovery of
1925 * larger MTUs on the path. With that limit raised, we can now
1926 * discover larger MTUs
1927 * A special case is locked exceptions, for which the PMTU is smaller
1928 * than the minimal accepted PMTU:
1929 * - if the new MTU is greater than the PMTU, don't make any change
1930 * - otherwise, unlock and set PMTU
1931 */
1932void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1933{
1934 struct fnhe_hash_bucket *bucket;
1935 int i;
1936
1937 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1938 if (!bucket)
1939 return;
1940
1941 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1942 struct fib_nh_exception *fnhe;
1943
1944 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1945 fnhe;
1946 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1947 if (fnhe->fnhe_mtu_locked) {
1948 if (new <= fnhe->fnhe_pmtu) {
1949 fnhe->fnhe_pmtu = new;
1950 fnhe->fnhe_mtu_locked = false;
1951 }
1952 } else if (new < fnhe->fnhe_pmtu ||
1953 orig == fnhe->fnhe_pmtu) {
1954 fnhe->fnhe_pmtu = new;
1955 }
1956 }
1957 }
1958}
1959
1960void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1961{
1962 struct hlist_head *head = fib_info_devhash_bucket(dev);
1963 struct fib_nh *nh;
1964
1965 hlist_for_each_entry(nh, head, nh_hash) {
1966 if (nh->fib_nh_dev == dev)
1967 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1968 }
1969}
1970
1971/* Event force Flags Description
1972 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1973 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1974 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1975 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1976 *
1977 * only used when fib_nh is built into fib_info
1978 */
1979int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1980{
1981 struct hlist_head *head = fib_info_devhash_bucket(dev);
1982 struct fib_info *prev_fi = NULL;
1983 int scope = RT_SCOPE_NOWHERE;
1984 struct fib_nh *nh;
1985 int ret = 0;
1986
1987 if (force)
1988 scope = -1;
1989
1990 hlist_for_each_entry(nh, head, nh_hash) {
1991 struct fib_info *fi = nh->nh_parent;
1992 int dead;
1993
1994 BUG_ON(!fi->fib_nhs);
1995 if (nh->fib_nh_dev != dev || fi == prev_fi)
1996 continue;
1997 prev_fi = fi;
1998 dead = 0;
1999 change_nexthops(fi) {
2000 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
2001 dead++;
2002 else if (nexthop_nh->fib_nh_dev == dev &&
2003 nexthop_nh->fib_nh_scope != scope) {
2004 switch (event) {
2005 case NETDEV_DOWN:
2006 case NETDEV_UNREGISTER:
2007 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
2008 fallthrough;
2009 case NETDEV_CHANGE:
2010 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
2011 break;
2012 }
2013 call_fib_nh_notifiers(nexthop_nh,
2014 FIB_EVENT_NH_DEL);
2015 dead++;
2016 }
2017#ifdef CONFIG_IP_ROUTE_MULTIPATH
2018 if (event == NETDEV_UNREGISTER &&
2019 nexthop_nh->fib_nh_dev == dev) {
2020 dead = fi->fib_nhs;
2021 break;
2022 }
2023#endif
2024 } endfor_nexthops(fi)
2025 if (dead == fi->fib_nhs) {
2026 switch (event) {
2027 case NETDEV_DOWN:
2028 case NETDEV_UNREGISTER:
2029 fi->fib_flags |= RTNH_F_DEAD;
2030 fallthrough;
2031 case NETDEV_CHANGE:
2032 fi->fib_flags |= RTNH_F_LINKDOWN;
2033 break;
2034 }
2035 ret++;
2036 }
2037
2038 fib_rebalance(fi);
2039 }
2040
2041 return ret;
2042}
2043
2044/* Must be invoked inside of an RCU protected region. */
2045static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2046{
2047 struct fib_info *fi = NULL, *last_resort = NULL;
2048 struct hlist_head *fa_head = res->fa_head;
2049 struct fib_table *tb = res->table;
2050 u8 slen = 32 - res->prefixlen;
2051 int order = -1, last_idx = -1;
2052 struct fib_alias *fa, *fa1 = NULL;
2053 u32 last_prio = res->fi->fib_priority;
2054 dscp_t last_dscp = 0;
2055
2056 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2057 struct fib_info *next_fi = fa->fa_info;
2058 struct fib_nh_common *nhc;
2059
2060 if (fa->fa_slen != slen)
2061 continue;
2062 if (fa->fa_dscp &&
2063 fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos))
2064 continue;
2065 if (fa->tb_id != tb->tb_id)
2066 continue;
2067 if (next_fi->fib_priority > last_prio &&
2068 fa->fa_dscp == last_dscp) {
2069 if (last_dscp)
2070 continue;
2071 break;
2072 }
2073 if (next_fi->fib_flags & RTNH_F_DEAD)
2074 continue;
2075 last_dscp = fa->fa_dscp;
2076 last_prio = next_fi->fib_priority;
2077
2078 if (next_fi->fib_scope != res->scope ||
2079 fa->fa_type != RTN_UNICAST)
2080 continue;
2081
2082 nhc = fib_info_nhc(next_fi, 0);
2083 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2084 continue;
2085
2086 fib_alias_accessed(fa);
2087
2088 if (!fi) {
2089 if (next_fi != res->fi)
2090 break;
2091 fa1 = fa;
2092 } else if (!fib_detect_death(fi, order, &last_resort,
2093 &last_idx, fa1->fa_default)) {
2094 fib_result_assign(res, fi);
2095 fa1->fa_default = order;
2096 goto out;
2097 }
2098 fi = next_fi;
2099 order++;
2100 }
2101
2102 if (order <= 0 || !fi) {
2103 if (fa1)
2104 fa1->fa_default = -1;
2105 goto out;
2106 }
2107
2108 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2109 fa1->fa_default)) {
2110 fib_result_assign(res, fi);
2111 fa1->fa_default = order;
2112 goto out;
2113 }
2114
2115 if (last_idx >= 0)
2116 fib_result_assign(res, last_resort);
2117 fa1->fa_default = last_idx;
2118out:
2119 return;
2120}
2121
2122/*
2123 * Dead device goes up. We wake up dead nexthops.
2124 * It takes sense only on multipath routes.
2125 *
2126 * only used when fib_nh is built into fib_info
2127 */
2128int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2129{
2130 struct fib_info *prev_fi;
2131 struct hlist_head *head;
2132 struct fib_nh *nh;
2133 int ret;
2134
2135 if (!(dev->flags & IFF_UP))
2136 return 0;
2137
2138 if (nh_flags & RTNH_F_DEAD) {
2139 unsigned int flags = dev_get_flags(dev);
2140
2141 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2142 nh_flags |= RTNH_F_LINKDOWN;
2143 }
2144
2145 prev_fi = NULL;
2146 head = fib_info_devhash_bucket(dev);
2147 ret = 0;
2148
2149 hlist_for_each_entry(nh, head, nh_hash) {
2150 struct fib_info *fi = nh->nh_parent;
2151 int alive;
2152
2153 BUG_ON(!fi->fib_nhs);
2154 if (nh->fib_nh_dev != dev || fi == prev_fi)
2155 continue;
2156
2157 prev_fi = fi;
2158 alive = 0;
2159 change_nexthops(fi) {
2160 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2161 alive++;
2162 continue;
2163 }
2164 if (!nexthop_nh->fib_nh_dev ||
2165 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2166 continue;
2167 if (nexthop_nh->fib_nh_dev != dev ||
2168 !__in_dev_get_rtnl(dev))
2169 continue;
2170 alive++;
2171 nexthop_nh->fib_nh_flags &= ~nh_flags;
2172 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2173 } endfor_nexthops(fi)
2174
2175 if (alive > 0) {
2176 fi->fib_flags &= ~nh_flags;
2177 ret++;
2178 }
2179
2180 fib_rebalance(fi);
2181 }
2182
2183 return ret;
2184}
2185
2186#ifdef CONFIG_IP_ROUTE_MULTIPATH
2187static bool fib_good_nh(const struct fib_nh *nh)
2188{
2189 int state = NUD_REACHABLE;
2190
2191 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2192 struct neighbour *n;
2193
2194 rcu_read_lock_bh();
2195
2196 if (likely(nh->fib_nh_gw_family == AF_INET))
2197 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2198 (__force u32)nh->fib_nh_gw4);
2199 else if (nh->fib_nh_gw_family == AF_INET6)
2200 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2201 &nh->fib_nh_gw6);
2202 else
2203 n = NULL;
2204 if (n)
2205 state = n->nud_state;
2206
2207 rcu_read_unlock_bh();
2208 }
2209
2210 return !!(state & NUD_VALID);
2211}
2212
2213void fib_select_multipath(struct fib_result *res, int hash)
2214{
2215 struct fib_info *fi = res->fi;
2216 struct net *net = fi->fib_net;
2217 bool first = false;
2218
2219 if (unlikely(res->fi->nh)) {
2220 nexthop_path_fib_result(res, hash);
2221 return;
2222 }
2223
2224 change_nexthops(fi) {
2225 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) {
2226 if (!fib_good_nh(nexthop_nh))
2227 continue;
2228 if (!first) {
2229 res->nh_sel = nhsel;
2230 res->nhc = &nexthop_nh->nh_common;
2231 first = true;
2232 }
2233 }
2234
2235 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2236 continue;
2237
2238 res->nh_sel = nhsel;
2239 res->nhc = &nexthop_nh->nh_common;
2240 return;
2241 } endfor_nexthops(fi);
2242}
2243#endif
2244
2245void fib_select_path(struct net *net, struct fib_result *res,
2246 struct flowi4 *fl4, const struct sk_buff *skb)
2247{
2248 if (fl4->flowi4_oif)
2249 goto check_saddr;
2250
2251#ifdef CONFIG_IP_ROUTE_MULTIPATH
2252 if (fib_info_num_path(res->fi) > 1) {
2253 int h = fib_multipath_hash(net, fl4, skb, NULL);
2254
2255 fib_select_multipath(res, h);
2256 }
2257 else
2258#endif
2259 if (!res->prefixlen &&
2260 res->table->tb_num_default > 1 &&
2261 res->type == RTN_UNICAST)
2262 fib_select_default(fl4, res);
2263
2264check_saddr:
2265 if (!fl4->saddr)
2266 fl4->saddr = fib_result_prefsrc(net, res);
2267}