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