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[mirror_ubuntu-focal-kernel.git] / net / ipv4 / fib_semantics.c
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
51 static DEFINE_SPINLOCK(fib_info_lock);
52 static struct hlist_head *fib_info_hash;
53 static struct hlist_head *fib_info_laddrhash;
54 static unsigned int fib_info_hash_size;
55 static unsigned int fib_info_cnt;
56
57 #define DEVINDEX_HASHBITS 8
58 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
59 static 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
93 const struct fib_prop fib_props[RTN_MAX + 1] = {
94 [RTN_UNSPEC] = {
95 .error = 0,
96 .scope = RT_SCOPE_NOWHERE,
97 },
98 [RTN_UNICAST] = {
99 .error = 0,
100 .scope = RT_SCOPE_UNIVERSE,
101 },
102 [RTN_LOCAL] = {
103 .error = 0,
104 .scope = RT_SCOPE_HOST,
105 },
106 [RTN_BROADCAST] = {
107 .error = 0,
108 .scope = RT_SCOPE_LINK,
109 },
110 [RTN_ANYCAST] = {
111 .error = 0,
112 .scope = RT_SCOPE_LINK,
113 },
114 [RTN_MULTICAST] = {
115 .error = 0,
116 .scope = RT_SCOPE_UNIVERSE,
117 },
118 [RTN_BLACKHOLE] = {
119 .error = -EINVAL,
120 .scope = RT_SCOPE_UNIVERSE,
121 },
122 [RTN_UNREACHABLE] = {
123 .error = -EHOSTUNREACH,
124 .scope = RT_SCOPE_UNIVERSE,
125 },
126 [RTN_PROHIBIT] = {
127 .error = -EACCES,
128 .scope = RT_SCOPE_UNIVERSE,
129 },
130 [RTN_THROW] = {
131 .error = -EAGAIN,
132 .scope = RT_SCOPE_UNIVERSE,
133 },
134 [RTN_NAT] = {
135 .error = -EINVAL,
136 .scope = RT_SCOPE_NOWHERE,
137 },
138 [RTN_XRESOLVE] = {
139 .error = -EINVAL,
140 .scope = RT_SCOPE_NOWHERE,
141 },
142 };
143
144 static 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
160 static 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
188 static 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 */
208 static void free_fib_info_rcu(struct rcu_head *head)
209 {
210 struct fib_info *fi = container_of(head, struct fib_info, rcu);
211 struct dst_metrics *m;
212
213 change_nexthops(fi) {
214 if (nexthop_nh->nh_dev)
215 dev_put(nexthop_nh->nh_dev);
216 lwtstate_put(nexthop_nh->nh_lwtstate);
217 free_nh_exceptions(nexthop_nh);
218 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
219 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
220 } endfor_nexthops(fi);
221
222 m = fi->fib_metrics;
223 if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
224 kfree(m);
225 kfree(fi);
226 }
227
228 void free_fib_info(struct fib_info *fi)
229 {
230 if (fi->fib_dead == 0) {
231 pr_warn("Freeing alive fib_info %p\n", fi);
232 return;
233 }
234 fib_info_cnt--;
235 #ifdef CONFIG_IP_ROUTE_CLASSID
236 change_nexthops(fi) {
237 if (nexthop_nh->nh_tclassid)
238 fi->fib_net->ipv4.fib_num_tclassid_users--;
239 } endfor_nexthops(fi);
240 #endif
241 call_rcu(&fi->rcu, free_fib_info_rcu);
242 }
243 EXPORT_SYMBOL_GPL(free_fib_info);
244
245 void fib_release_info(struct fib_info *fi)
246 {
247 spin_lock_bh(&fib_info_lock);
248 if (fi && --fi->fib_treeref == 0) {
249 hlist_del(&fi->fib_hash);
250 if (fi->fib_prefsrc)
251 hlist_del(&fi->fib_lhash);
252 change_nexthops(fi) {
253 if (!nexthop_nh->nh_dev)
254 continue;
255 hlist_del(&nexthop_nh->nh_hash);
256 } endfor_nexthops(fi)
257 fi->fib_dead = 1;
258 fib_info_put(fi);
259 }
260 spin_unlock_bh(&fib_info_lock);
261 }
262
263 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
264 {
265 const struct fib_nh *onh = ofi->fib_nh;
266
267 for_nexthops(fi) {
268 if (nh->nh_oif != onh->nh_oif ||
269 nh->nh_gw != onh->nh_gw ||
270 nh->nh_scope != onh->nh_scope ||
271 #ifdef CONFIG_IP_ROUTE_MULTIPATH
272 nh->nh_weight != onh->nh_weight ||
273 #endif
274 #ifdef CONFIG_IP_ROUTE_CLASSID
275 nh->nh_tclassid != onh->nh_tclassid ||
276 #endif
277 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
278 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
279 return -1;
280 onh++;
281 } endfor_nexthops(fi);
282 return 0;
283 }
284
285 static inline unsigned int fib_devindex_hashfn(unsigned int val)
286 {
287 unsigned int mask = DEVINDEX_HASHSIZE - 1;
288
289 return (val ^
290 (val >> DEVINDEX_HASHBITS) ^
291 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
292 }
293
294 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
295 {
296 unsigned int mask = (fib_info_hash_size - 1);
297 unsigned int val = fi->fib_nhs;
298
299 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
300 val ^= (__force u32)fi->fib_prefsrc;
301 val ^= fi->fib_priority;
302 for_nexthops(fi) {
303 val ^= fib_devindex_hashfn(nh->nh_oif);
304 } endfor_nexthops(fi)
305
306 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
307 }
308
309 static struct fib_info *fib_find_info(const struct fib_info *nfi)
310 {
311 struct hlist_head *head;
312 struct fib_info *fi;
313 unsigned int hash;
314
315 hash = fib_info_hashfn(nfi);
316 head = &fib_info_hash[hash];
317
318 hlist_for_each_entry(fi, head, fib_hash) {
319 if (!net_eq(fi->fib_net, nfi->fib_net))
320 continue;
321 if (fi->fib_nhs != nfi->fib_nhs)
322 continue;
323 if (nfi->fib_protocol == fi->fib_protocol &&
324 nfi->fib_scope == fi->fib_scope &&
325 nfi->fib_prefsrc == fi->fib_prefsrc &&
326 nfi->fib_priority == fi->fib_priority &&
327 nfi->fib_type == fi->fib_type &&
328 memcmp(nfi->fib_metrics, fi->fib_metrics,
329 sizeof(u32) * RTAX_MAX) == 0 &&
330 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
331 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
332 return fi;
333 }
334
335 return NULL;
336 }
337
338 /* Check, that the gateway is already configured.
339 * Used only by redirect accept routine.
340 */
341 int ip_fib_check_default(__be32 gw, struct net_device *dev)
342 {
343 struct hlist_head *head;
344 struct fib_nh *nh;
345 unsigned int hash;
346
347 spin_lock(&fib_info_lock);
348
349 hash = fib_devindex_hashfn(dev->ifindex);
350 head = &fib_info_devhash[hash];
351 hlist_for_each_entry(nh, head, nh_hash) {
352 if (nh->nh_dev == dev &&
353 nh->nh_gw == gw &&
354 !(nh->nh_flags & RTNH_F_DEAD)) {
355 spin_unlock(&fib_info_lock);
356 return 0;
357 }
358 }
359
360 spin_unlock(&fib_info_lock);
361
362 return -1;
363 }
364
365 static inline size_t fib_nlmsg_size(struct fib_info *fi)
366 {
367 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
368 + nla_total_size(4) /* RTA_TABLE */
369 + nla_total_size(4) /* RTA_DST */
370 + nla_total_size(4) /* RTA_PRIORITY */
371 + nla_total_size(4) /* RTA_PREFSRC */
372 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
373
374 /* space for nested metrics */
375 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
376
377 if (fi->fib_nhs) {
378 size_t nh_encapsize = 0;
379 /* Also handles the special case fib_nhs == 1 */
380
381 /* each nexthop is packed in an attribute */
382 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
383
384 /* may contain flow and gateway attribute */
385 nhsize += 2 * nla_total_size(4);
386
387 /* grab encap info */
388 for_nexthops(fi) {
389 if (nh->nh_lwtstate) {
390 /* RTA_ENCAP_TYPE */
391 nh_encapsize += lwtunnel_get_encap_size(
392 nh->nh_lwtstate);
393 /* RTA_ENCAP */
394 nh_encapsize += nla_total_size(2);
395 }
396 } endfor_nexthops(fi);
397
398 /* all nexthops are packed in a nested attribute */
399 payload += nla_total_size((fi->fib_nhs * nhsize) +
400 nh_encapsize);
401
402 }
403
404 return payload;
405 }
406
407 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
408 int dst_len, u32 tb_id, const struct nl_info *info,
409 unsigned int nlm_flags)
410 {
411 struct sk_buff *skb;
412 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
413 int err = -ENOBUFS;
414
415 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
416 if (!skb)
417 goto errout;
418
419 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
420 fa->fa_type, key, dst_len,
421 fa->fa_tos, fa->fa_info, nlm_flags);
422 if (err < 0) {
423 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
424 WARN_ON(err == -EMSGSIZE);
425 kfree_skb(skb);
426 goto errout;
427 }
428 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
429 info->nlh, GFP_KERNEL);
430 return;
431 errout:
432 if (err < 0)
433 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
434 }
435
436 static int fib_detect_death(struct fib_info *fi, int order,
437 struct fib_info **last_resort, int *last_idx,
438 int dflt)
439 {
440 struct neighbour *n;
441 int state = NUD_NONE;
442
443 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
444 if (n) {
445 state = n->nud_state;
446 neigh_release(n);
447 } else {
448 return 0;
449 }
450 if (state == NUD_REACHABLE)
451 return 0;
452 if ((state & NUD_VALID) && order != dflt)
453 return 0;
454 if ((state & NUD_VALID) ||
455 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
456 *last_resort = fi;
457 *last_idx = order;
458 }
459 return 1;
460 }
461
462 #ifdef CONFIG_IP_ROUTE_MULTIPATH
463
464 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
465 struct netlink_ext_ack *extack)
466 {
467 int nhs = 0;
468
469 while (rtnh_ok(rtnh, remaining)) {
470 nhs++;
471 rtnh = rtnh_next(rtnh, &remaining);
472 }
473
474 /* leftover implies invalid nexthop configuration, discard it */
475 if (remaining > 0) {
476 NL_SET_ERR_MSG(extack,
477 "Invalid nexthop configuration - extra data after nexthops");
478 nhs = 0;
479 }
480
481 return nhs;
482 }
483
484 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
485 int remaining, struct fib_config *cfg,
486 struct netlink_ext_ack *extack)
487 {
488 int ret;
489
490 change_nexthops(fi) {
491 int attrlen;
492
493 if (!rtnh_ok(rtnh, remaining)) {
494 NL_SET_ERR_MSG(extack,
495 "Invalid nexthop configuration - extra data after nexthop");
496 return -EINVAL;
497 }
498
499 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
500 NL_SET_ERR_MSG(extack,
501 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
502 return -EINVAL;
503 }
504
505 nexthop_nh->nh_flags =
506 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
507 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
508 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
509
510 attrlen = rtnh_attrlen(rtnh);
511 if (attrlen > 0) {
512 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
513
514 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
515 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
516 #ifdef CONFIG_IP_ROUTE_CLASSID
517 nla = nla_find(attrs, attrlen, RTA_FLOW);
518 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
519 if (nexthop_nh->nh_tclassid)
520 fi->fib_net->ipv4.fib_num_tclassid_users++;
521 #endif
522 nla = nla_find(attrs, attrlen, RTA_ENCAP);
523 if (nla) {
524 struct lwtunnel_state *lwtstate;
525 struct nlattr *nla_entype;
526
527 nla_entype = nla_find(attrs, attrlen,
528 RTA_ENCAP_TYPE);
529 if (!nla_entype) {
530 NL_SET_BAD_ATTR(extack, nla);
531 NL_SET_ERR_MSG(extack,
532 "Encap type is missing");
533 goto err_inval;
534 }
535
536 ret = lwtunnel_build_state(nla_get_u16(
537 nla_entype),
538 nla, AF_INET, cfg,
539 &lwtstate, extack);
540 if (ret)
541 goto errout;
542 nexthop_nh->nh_lwtstate =
543 lwtstate_get(lwtstate);
544 }
545 }
546
547 rtnh = rtnh_next(rtnh, &remaining);
548 } endfor_nexthops(fi);
549
550 return 0;
551
552 err_inval:
553 ret = -EINVAL;
554
555 errout:
556 return ret;
557 }
558
559 static void fib_rebalance(struct fib_info *fi)
560 {
561 int total;
562 int w;
563 struct in_device *in_dev;
564
565 if (fi->fib_nhs < 2)
566 return;
567
568 total = 0;
569 for_nexthops(fi) {
570 if (nh->nh_flags & RTNH_F_DEAD)
571 continue;
572
573 in_dev = __in_dev_get_rtnl(nh->nh_dev);
574
575 if (in_dev &&
576 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
577 nh->nh_flags & RTNH_F_LINKDOWN)
578 continue;
579
580 total += nh->nh_weight;
581 } endfor_nexthops(fi);
582
583 w = 0;
584 change_nexthops(fi) {
585 int upper_bound;
586
587 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
588
589 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
590 upper_bound = -1;
591 } else if (in_dev &&
592 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
593 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
594 upper_bound = -1;
595 } else {
596 w += nexthop_nh->nh_weight;
597 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
598 total) - 1;
599 }
600
601 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
602 } endfor_nexthops(fi);
603 }
604 #else /* CONFIG_IP_ROUTE_MULTIPATH */
605
606 #define fib_rebalance(fi) do { } while (0)
607
608 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
609
610 static int fib_encap_match(u16 encap_type,
611 struct nlattr *encap,
612 const struct fib_nh *nh,
613 const struct fib_config *cfg,
614 struct netlink_ext_ack *extack)
615 {
616 struct lwtunnel_state *lwtstate;
617 int ret, result = 0;
618
619 if (encap_type == LWTUNNEL_ENCAP_NONE)
620 return 0;
621
622 ret = lwtunnel_build_state(encap_type, encap, AF_INET,
623 cfg, &lwtstate, extack);
624 if (!ret) {
625 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
626 lwtstate_free(lwtstate);
627 }
628
629 return result;
630 }
631
632 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
633 struct netlink_ext_ack *extack)
634 {
635 #ifdef CONFIG_IP_ROUTE_MULTIPATH
636 struct rtnexthop *rtnh;
637 int remaining;
638 #endif
639
640 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
641 return 1;
642
643 if (cfg->fc_oif || cfg->fc_gw) {
644 if (cfg->fc_encap) {
645 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
646 fi->fib_nh, cfg, extack))
647 return 1;
648 }
649 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
650 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
651 return 0;
652 return 1;
653 }
654
655 #ifdef CONFIG_IP_ROUTE_MULTIPATH
656 if (!cfg->fc_mp)
657 return 0;
658
659 rtnh = cfg->fc_mp;
660 remaining = cfg->fc_mp_len;
661
662 for_nexthops(fi) {
663 int attrlen;
664
665 if (!rtnh_ok(rtnh, remaining))
666 return -EINVAL;
667
668 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
669 return 1;
670
671 attrlen = rtnh_attrlen(rtnh);
672 if (attrlen > 0) {
673 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
674
675 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
676 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
677 return 1;
678 #ifdef CONFIG_IP_ROUTE_CLASSID
679 nla = nla_find(attrs, attrlen, RTA_FLOW);
680 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
681 return 1;
682 #endif
683 }
684
685 rtnh = rtnh_next(rtnh, &remaining);
686 } endfor_nexthops(fi);
687 #endif
688 return 0;
689 }
690
691 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
692 {
693 struct nlattr *nla;
694 int remaining;
695
696 if (!cfg->fc_mx)
697 return true;
698
699 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
700 int type = nla_type(nla);
701 u32 fi_val, val;
702
703 if (!type)
704 continue;
705 if (type > RTAX_MAX)
706 return false;
707
708 if (type == RTAX_CC_ALGO) {
709 char tmp[TCP_CA_NAME_MAX];
710 bool ecn_ca = false;
711
712 nla_strlcpy(tmp, nla, sizeof(tmp));
713 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
714 } else {
715 val = nla_get_u32(nla);
716 }
717
718 fi_val = fi->fib_metrics->metrics[type - 1];
719 if (type == RTAX_FEATURES)
720 fi_val &= ~DST_FEATURE_ECN_CA;
721
722 if (fi_val != val)
723 return false;
724 }
725
726 return true;
727 }
728
729
730 /*
731 * Picture
732 * -------
733 *
734 * Semantics of nexthop is very messy by historical reasons.
735 * We have to take into account, that:
736 * a) gateway can be actually local interface address,
737 * so that gatewayed route is direct.
738 * b) gateway must be on-link address, possibly
739 * described not by an ifaddr, but also by a direct route.
740 * c) If both gateway and interface are specified, they should not
741 * contradict.
742 * d) If we use tunnel routes, gateway could be not on-link.
743 *
744 * Attempt to reconcile all of these (alas, self-contradictory) conditions
745 * results in pretty ugly and hairy code with obscure logic.
746 *
747 * I chose to generalized it instead, so that the size
748 * of code does not increase practically, but it becomes
749 * much more general.
750 * Every prefix is assigned a "scope" value: "host" is local address,
751 * "link" is direct route,
752 * [ ... "site" ... "interior" ... ]
753 * and "universe" is true gateway route with global meaning.
754 *
755 * Every prefix refers to a set of "nexthop"s (gw, oif),
756 * where gw must have narrower scope. This recursion stops
757 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
758 * which means that gw is forced to be on link.
759 *
760 * Code is still hairy, but now it is apparently logically
761 * consistent and very flexible. F.e. as by-product it allows
762 * to co-exists in peace independent exterior and interior
763 * routing processes.
764 *
765 * Normally it looks as following.
766 *
767 * {universe prefix} -> (gw, oif) [scope link]
768 * |
769 * |-> {link prefix} -> (gw, oif) [scope local]
770 * |
771 * |-> {local prefix} (terminal node)
772 */
773 static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh,
774 struct netlink_ext_ack *extack)
775 {
776 int err = 0;
777 struct net *net;
778 struct net_device *dev;
779
780 net = cfg->fc_nlinfo.nl_net;
781 if (nh->nh_gw) {
782 struct fib_result res;
783
784 if (nh->nh_flags & RTNH_F_ONLINK) {
785 unsigned int addr_type;
786
787 if (cfg->fc_scope >= RT_SCOPE_LINK) {
788 NL_SET_ERR_MSG(extack,
789 "Nexthop has invalid scope");
790 return -EINVAL;
791 }
792 dev = __dev_get_by_index(net, nh->nh_oif);
793 if (!dev)
794 return -ENODEV;
795 if (!(dev->flags & IFF_UP)) {
796 NL_SET_ERR_MSG(extack,
797 "Nexthop device is not up");
798 return -ENETDOWN;
799 }
800 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
801 if (addr_type != RTN_UNICAST) {
802 NL_SET_ERR_MSG(extack,
803 "Nexthop has invalid gateway");
804 return -EINVAL;
805 }
806 if (!netif_carrier_ok(dev))
807 nh->nh_flags |= RTNH_F_LINKDOWN;
808 nh->nh_dev = dev;
809 dev_hold(dev);
810 nh->nh_scope = RT_SCOPE_LINK;
811 return 0;
812 }
813 rcu_read_lock();
814 {
815 struct fib_table *tbl = NULL;
816 struct flowi4 fl4 = {
817 .daddr = nh->nh_gw,
818 .flowi4_scope = cfg->fc_scope + 1,
819 .flowi4_oif = nh->nh_oif,
820 .flowi4_iif = LOOPBACK_IFINDEX,
821 };
822
823 /* It is not necessary, but requires a bit of thinking */
824 if (fl4.flowi4_scope < RT_SCOPE_LINK)
825 fl4.flowi4_scope = RT_SCOPE_LINK;
826
827 if (cfg->fc_table)
828 tbl = fib_get_table(net, cfg->fc_table);
829
830 if (tbl)
831 err = fib_table_lookup(tbl, &fl4, &res,
832 FIB_LOOKUP_IGNORE_LINKSTATE |
833 FIB_LOOKUP_NOREF);
834
835 /* on error or if no table given do full lookup. This
836 * is needed for example when nexthops are in the local
837 * table rather than the given table
838 */
839 if (!tbl || err) {
840 err = fib_lookup(net, &fl4, &res,
841 FIB_LOOKUP_IGNORE_LINKSTATE);
842 }
843
844 if (err) {
845 NL_SET_ERR_MSG(extack,
846 "Nexthop has invalid gateway");
847 rcu_read_unlock();
848 return err;
849 }
850 }
851 err = -EINVAL;
852 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
853 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
854 goto out;
855 }
856 nh->nh_scope = res.scope;
857 nh->nh_oif = FIB_RES_OIF(res);
858 nh->nh_dev = dev = FIB_RES_DEV(res);
859 if (!dev) {
860 NL_SET_ERR_MSG(extack,
861 "No egress device for nexthop gateway");
862 goto out;
863 }
864 dev_hold(dev);
865 if (!netif_carrier_ok(dev))
866 nh->nh_flags |= RTNH_F_LINKDOWN;
867 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
868 } else {
869 struct in_device *in_dev;
870
871 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
872 NL_SET_ERR_MSG(extack,
873 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
874 return -EINVAL;
875 }
876 rcu_read_lock();
877 err = -ENODEV;
878 in_dev = inetdev_by_index(net, nh->nh_oif);
879 if (!in_dev)
880 goto out;
881 err = -ENETDOWN;
882 if (!(in_dev->dev->flags & IFF_UP)) {
883 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
884 goto out;
885 }
886 nh->nh_dev = in_dev->dev;
887 dev_hold(nh->nh_dev);
888 nh->nh_scope = RT_SCOPE_HOST;
889 if (!netif_carrier_ok(nh->nh_dev))
890 nh->nh_flags |= RTNH_F_LINKDOWN;
891 err = 0;
892 }
893 out:
894 rcu_read_unlock();
895 return err;
896 }
897
898 static inline unsigned int fib_laddr_hashfn(__be32 val)
899 {
900 unsigned int mask = (fib_info_hash_size - 1);
901
902 return ((__force u32)val ^
903 ((__force u32)val >> 7) ^
904 ((__force u32)val >> 14)) & mask;
905 }
906
907 static struct hlist_head *fib_info_hash_alloc(int bytes)
908 {
909 if (bytes <= PAGE_SIZE)
910 return kzalloc(bytes, GFP_KERNEL);
911 else
912 return (struct hlist_head *)
913 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
914 get_order(bytes));
915 }
916
917 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
918 {
919 if (!hash)
920 return;
921
922 if (bytes <= PAGE_SIZE)
923 kfree(hash);
924 else
925 free_pages((unsigned long) hash, get_order(bytes));
926 }
927
928 static void fib_info_hash_move(struct hlist_head *new_info_hash,
929 struct hlist_head *new_laddrhash,
930 unsigned int new_size)
931 {
932 struct hlist_head *old_info_hash, *old_laddrhash;
933 unsigned int old_size = fib_info_hash_size;
934 unsigned int i, bytes;
935
936 spin_lock_bh(&fib_info_lock);
937 old_info_hash = fib_info_hash;
938 old_laddrhash = fib_info_laddrhash;
939 fib_info_hash_size = new_size;
940
941 for (i = 0; i < old_size; i++) {
942 struct hlist_head *head = &fib_info_hash[i];
943 struct hlist_node *n;
944 struct fib_info *fi;
945
946 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
947 struct hlist_head *dest;
948 unsigned int new_hash;
949
950 new_hash = fib_info_hashfn(fi);
951 dest = &new_info_hash[new_hash];
952 hlist_add_head(&fi->fib_hash, dest);
953 }
954 }
955 fib_info_hash = new_info_hash;
956
957 for (i = 0; i < old_size; i++) {
958 struct hlist_head *lhead = &fib_info_laddrhash[i];
959 struct hlist_node *n;
960 struct fib_info *fi;
961
962 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
963 struct hlist_head *ldest;
964 unsigned int new_hash;
965
966 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
967 ldest = &new_laddrhash[new_hash];
968 hlist_add_head(&fi->fib_lhash, ldest);
969 }
970 }
971 fib_info_laddrhash = new_laddrhash;
972
973 spin_unlock_bh(&fib_info_lock);
974
975 bytes = old_size * sizeof(struct hlist_head *);
976 fib_info_hash_free(old_info_hash, bytes);
977 fib_info_hash_free(old_laddrhash, bytes);
978 }
979
980 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
981 {
982 nh->nh_saddr = inet_select_addr(nh->nh_dev,
983 nh->nh_gw,
984 nh->nh_parent->fib_scope);
985 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
986
987 return nh->nh_saddr;
988 }
989
990 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
991 {
992 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
993 fib_prefsrc != cfg->fc_dst) {
994 u32 tb_id = cfg->fc_table;
995 int rc;
996
997 if (tb_id == RT_TABLE_MAIN)
998 tb_id = RT_TABLE_LOCAL;
999
1000 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1001 fib_prefsrc, tb_id);
1002
1003 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1004 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1005 fib_prefsrc, RT_TABLE_LOCAL);
1006 }
1007
1008 if (rc != RTN_LOCAL)
1009 return false;
1010 }
1011 return true;
1012 }
1013
1014 static int
1015 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
1016 {
1017 bool ecn_ca = false;
1018 struct nlattr *nla;
1019 int remaining;
1020
1021 if (!cfg->fc_mx)
1022 return 0;
1023
1024 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1025 int type = nla_type(nla);
1026 u32 val;
1027
1028 if (!type)
1029 continue;
1030 if (type > RTAX_MAX)
1031 return -EINVAL;
1032
1033 if (type == RTAX_CC_ALGO) {
1034 char tmp[TCP_CA_NAME_MAX];
1035
1036 nla_strlcpy(tmp, nla, sizeof(tmp));
1037 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1038 if (val == TCP_CA_UNSPEC)
1039 return -EINVAL;
1040 } else {
1041 val = nla_get_u32(nla);
1042 }
1043 if (type == RTAX_ADVMSS && val > 65535 - 40)
1044 val = 65535 - 40;
1045 if (type == RTAX_MTU && val > 65535 - 15)
1046 val = 65535 - 15;
1047 if (type == RTAX_HOPLIMIT && val > 255)
1048 val = 255;
1049 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
1050 return -EINVAL;
1051 fi->fib_metrics->metrics[type - 1] = val;
1052 }
1053
1054 if (ecn_ca)
1055 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
1056
1057 return 0;
1058 }
1059
1060 struct fib_info *fib_create_info(struct fib_config *cfg,
1061 struct netlink_ext_ack *extack)
1062 {
1063 int err;
1064 struct fib_info *fi = NULL;
1065 struct fib_info *ofi;
1066 int nhs = 1;
1067 struct net *net = cfg->fc_nlinfo.nl_net;
1068
1069 if (cfg->fc_type > RTN_MAX)
1070 goto err_inval;
1071
1072 /* Fast check to catch the most weird cases */
1073 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1074 NL_SET_ERR_MSG(extack, "Invalid scope");
1075 goto err_inval;
1076 }
1077
1078 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1079 NL_SET_ERR_MSG(extack,
1080 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1081 goto err_inval;
1082 }
1083
1084 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1085 if (cfg->fc_mp) {
1086 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1087 if (nhs == 0)
1088 goto err_inval;
1089 }
1090 #endif
1091
1092 err = -ENOBUFS;
1093 if (fib_info_cnt >= fib_info_hash_size) {
1094 unsigned int new_size = fib_info_hash_size << 1;
1095 struct hlist_head *new_info_hash;
1096 struct hlist_head *new_laddrhash;
1097 unsigned int bytes;
1098
1099 if (!new_size)
1100 new_size = 16;
1101 bytes = new_size * sizeof(struct hlist_head *);
1102 new_info_hash = fib_info_hash_alloc(bytes);
1103 new_laddrhash = fib_info_hash_alloc(bytes);
1104 if (!new_info_hash || !new_laddrhash) {
1105 fib_info_hash_free(new_info_hash, bytes);
1106 fib_info_hash_free(new_laddrhash, bytes);
1107 } else
1108 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1109
1110 if (!fib_info_hash_size)
1111 goto failure;
1112 }
1113
1114 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1115 if (!fi)
1116 goto failure;
1117 if (cfg->fc_mx) {
1118 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
1119 if (unlikely(!fi->fib_metrics)) {
1120 kfree(fi);
1121 return ERR_PTR(err);
1122 }
1123 refcount_set(&fi->fib_metrics->refcnt, 1);
1124 } else {
1125 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
1126 }
1127 fib_info_cnt++;
1128 fi->fib_net = net;
1129 fi->fib_protocol = cfg->fc_protocol;
1130 fi->fib_scope = cfg->fc_scope;
1131 fi->fib_flags = cfg->fc_flags;
1132 fi->fib_priority = cfg->fc_priority;
1133 fi->fib_prefsrc = cfg->fc_prefsrc;
1134 fi->fib_type = cfg->fc_type;
1135 fi->fib_tb_id = cfg->fc_table;
1136
1137 fi->fib_nhs = nhs;
1138 change_nexthops(fi) {
1139 nexthop_nh->nh_parent = fi;
1140 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1141 if (!nexthop_nh->nh_pcpu_rth_output)
1142 goto failure;
1143 } endfor_nexthops(fi)
1144
1145 err = fib_convert_metrics(fi, cfg);
1146 if (err)
1147 goto failure;
1148
1149 if (cfg->fc_mp) {
1150 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1151 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1152 if (err != 0)
1153 goto failure;
1154 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
1155 NL_SET_ERR_MSG(extack,
1156 "Nexthop device index does not match RTA_OIF");
1157 goto err_inval;
1158 }
1159 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
1160 NL_SET_ERR_MSG(extack,
1161 "Nexthop gateway does not match RTA_GATEWAY");
1162 goto err_inval;
1163 }
1164 #ifdef CONFIG_IP_ROUTE_CLASSID
1165 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
1166 NL_SET_ERR_MSG(extack,
1167 "Nexthop class id does not match RTA_FLOW");
1168 goto err_inval;
1169 }
1170 #endif
1171 #else
1172 NL_SET_ERR_MSG(extack,
1173 "Multipath support not enabled in kernel");
1174 goto err_inval;
1175 #endif
1176 } else {
1177 struct fib_nh *nh = fi->fib_nh;
1178
1179 if (cfg->fc_encap) {
1180 struct lwtunnel_state *lwtstate;
1181
1182 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
1183 NL_SET_ERR_MSG(extack,
1184 "LWT encap type not specified");
1185 goto err_inval;
1186 }
1187 err = lwtunnel_build_state(cfg->fc_encap_type,
1188 cfg->fc_encap, AF_INET, cfg,
1189 &lwtstate, extack);
1190 if (err)
1191 goto failure;
1192
1193 nh->nh_lwtstate = lwtstate_get(lwtstate);
1194 }
1195 nh->nh_oif = cfg->fc_oif;
1196 nh->nh_gw = cfg->fc_gw;
1197 nh->nh_flags = cfg->fc_flags;
1198 #ifdef CONFIG_IP_ROUTE_CLASSID
1199 nh->nh_tclassid = cfg->fc_flow;
1200 if (nh->nh_tclassid)
1201 fi->fib_net->ipv4.fib_num_tclassid_users++;
1202 #endif
1203 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1204 nh->nh_weight = 1;
1205 #endif
1206 }
1207
1208 if (fib_props[cfg->fc_type].error) {
1209 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) {
1210 NL_SET_ERR_MSG(extack,
1211 "Gateway, device and multipath can not be specified for this route type");
1212 goto err_inval;
1213 }
1214 goto link_it;
1215 } else {
1216 switch (cfg->fc_type) {
1217 case RTN_UNICAST:
1218 case RTN_LOCAL:
1219 case RTN_BROADCAST:
1220 case RTN_ANYCAST:
1221 case RTN_MULTICAST:
1222 break;
1223 default:
1224 NL_SET_ERR_MSG(extack, "Invalid route type");
1225 goto err_inval;
1226 }
1227 }
1228
1229 if (cfg->fc_scope > RT_SCOPE_HOST) {
1230 NL_SET_ERR_MSG(extack, "Invalid scope");
1231 goto err_inval;
1232 }
1233
1234 if (cfg->fc_scope == RT_SCOPE_HOST) {
1235 struct fib_nh *nh = fi->fib_nh;
1236
1237 /* Local address is added. */
1238 if (nhs != 1) {
1239 NL_SET_ERR_MSG(extack,
1240 "Route with host scope can not have multiple nexthops");
1241 goto err_inval;
1242 }
1243 if (nh->nh_gw) {
1244 NL_SET_ERR_MSG(extack,
1245 "Route with host scope can not have a gateway");
1246 goto err_inval;
1247 }
1248 nh->nh_scope = RT_SCOPE_NOWHERE;
1249 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1250 err = -ENODEV;
1251 if (!nh->nh_dev)
1252 goto failure;
1253 } else {
1254 int linkdown = 0;
1255
1256 change_nexthops(fi) {
1257 err = fib_check_nh(cfg, nexthop_nh, extack);
1258 if (err != 0)
1259 goto failure;
1260 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1261 linkdown++;
1262 } endfor_nexthops(fi)
1263 if (linkdown == fi->fib_nhs)
1264 fi->fib_flags |= RTNH_F_LINKDOWN;
1265 }
1266
1267 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1268 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1269 goto err_inval;
1270 }
1271
1272 change_nexthops(fi) {
1273 fib_info_update_nh_saddr(net, nexthop_nh);
1274 } endfor_nexthops(fi)
1275
1276 fib_rebalance(fi);
1277
1278 link_it:
1279 ofi = fib_find_info(fi);
1280 if (ofi) {
1281 fi->fib_dead = 1;
1282 free_fib_info(fi);
1283 ofi->fib_treeref++;
1284 return ofi;
1285 }
1286
1287 fi->fib_treeref++;
1288 refcount_set(&fi->fib_clntref, 1);
1289 spin_lock_bh(&fib_info_lock);
1290 hlist_add_head(&fi->fib_hash,
1291 &fib_info_hash[fib_info_hashfn(fi)]);
1292 if (fi->fib_prefsrc) {
1293 struct hlist_head *head;
1294
1295 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1296 hlist_add_head(&fi->fib_lhash, head);
1297 }
1298 change_nexthops(fi) {
1299 struct hlist_head *head;
1300 unsigned int hash;
1301
1302 if (!nexthop_nh->nh_dev)
1303 continue;
1304 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1305 head = &fib_info_devhash[hash];
1306 hlist_add_head(&nexthop_nh->nh_hash, head);
1307 } endfor_nexthops(fi)
1308 spin_unlock_bh(&fib_info_lock);
1309 return fi;
1310
1311 err_inval:
1312 err = -EINVAL;
1313
1314 failure:
1315 if (fi) {
1316 fi->fib_dead = 1;
1317 free_fib_info(fi);
1318 }
1319
1320 return ERR_PTR(err);
1321 }
1322
1323 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1324 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1325 struct fib_info *fi, unsigned int flags)
1326 {
1327 struct nlmsghdr *nlh;
1328 struct rtmsg *rtm;
1329
1330 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1331 if (!nlh)
1332 return -EMSGSIZE;
1333
1334 rtm = nlmsg_data(nlh);
1335 rtm->rtm_family = AF_INET;
1336 rtm->rtm_dst_len = dst_len;
1337 rtm->rtm_src_len = 0;
1338 rtm->rtm_tos = tos;
1339 if (tb_id < 256)
1340 rtm->rtm_table = tb_id;
1341 else
1342 rtm->rtm_table = RT_TABLE_COMPAT;
1343 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1344 goto nla_put_failure;
1345 rtm->rtm_type = type;
1346 rtm->rtm_flags = fi->fib_flags;
1347 rtm->rtm_scope = fi->fib_scope;
1348 rtm->rtm_protocol = fi->fib_protocol;
1349
1350 if (rtm->rtm_dst_len &&
1351 nla_put_in_addr(skb, RTA_DST, dst))
1352 goto nla_put_failure;
1353 if (fi->fib_priority &&
1354 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1355 goto nla_put_failure;
1356 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1357 goto nla_put_failure;
1358
1359 if (fi->fib_prefsrc &&
1360 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1361 goto nla_put_failure;
1362 if (fi->fib_nhs == 1) {
1363 if (fi->fib_nh->nh_gw &&
1364 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1365 goto nla_put_failure;
1366 if (fi->fib_nh->nh_oif &&
1367 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1368 goto nla_put_failure;
1369 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1370 struct in_device *in_dev;
1371
1372 rcu_read_lock();
1373 in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev);
1374 if (in_dev &&
1375 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1376 rtm->rtm_flags |= RTNH_F_DEAD;
1377 rcu_read_unlock();
1378 }
1379 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD)
1380 rtm->rtm_flags |= RTNH_F_OFFLOAD;
1381 #ifdef CONFIG_IP_ROUTE_CLASSID
1382 if (fi->fib_nh[0].nh_tclassid &&
1383 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1384 goto nla_put_failure;
1385 #endif
1386 if (fi->fib_nh->nh_lwtstate &&
1387 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1388 goto nla_put_failure;
1389 }
1390 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1391 if (fi->fib_nhs > 1) {
1392 struct rtnexthop *rtnh;
1393 struct nlattr *mp;
1394
1395 mp = nla_nest_start(skb, RTA_MULTIPATH);
1396 if (!mp)
1397 goto nla_put_failure;
1398
1399 for_nexthops(fi) {
1400 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1401 if (!rtnh)
1402 goto nla_put_failure;
1403
1404 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1405 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1406 struct in_device *in_dev;
1407
1408 rcu_read_lock();
1409 in_dev = __in_dev_get_rcu(nh->nh_dev);
1410 if (in_dev &&
1411 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1412 rtnh->rtnh_flags |= RTNH_F_DEAD;
1413 rcu_read_unlock();
1414 }
1415 rtnh->rtnh_hops = nh->nh_weight - 1;
1416 rtnh->rtnh_ifindex = nh->nh_oif;
1417
1418 if (nh->nh_gw &&
1419 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1420 goto nla_put_failure;
1421 #ifdef CONFIG_IP_ROUTE_CLASSID
1422 if (nh->nh_tclassid &&
1423 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1424 goto nla_put_failure;
1425 #endif
1426 if (nh->nh_lwtstate &&
1427 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1428 goto nla_put_failure;
1429
1430 /* length of rtnetlink header + attributes */
1431 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1432 } endfor_nexthops(fi);
1433
1434 nla_nest_end(skb, mp);
1435 }
1436 #endif
1437 nlmsg_end(skb, nlh);
1438 return 0;
1439
1440 nla_put_failure:
1441 nlmsg_cancel(skb, nlh);
1442 return -EMSGSIZE;
1443 }
1444
1445 /*
1446 * Update FIB if:
1447 * - local address disappeared -> we must delete all the entries
1448 * referring to it.
1449 * - device went down -> we must shutdown all nexthops going via it.
1450 */
1451 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1452 {
1453 int ret = 0;
1454 unsigned int hash = fib_laddr_hashfn(local);
1455 struct hlist_head *head = &fib_info_laddrhash[hash];
1456 struct net *net = dev_net(dev);
1457 int tb_id = l3mdev_fib_table(dev);
1458 struct fib_info *fi;
1459
1460 if (!fib_info_laddrhash || local == 0)
1461 return 0;
1462
1463 hlist_for_each_entry(fi, head, fib_lhash) {
1464 if (!net_eq(fi->fib_net, net) ||
1465 fi->fib_tb_id != tb_id)
1466 continue;
1467 if (fi->fib_prefsrc == local) {
1468 fi->fib_flags |= RTNH_F_DEAD;
1469 ret++;
1470 }
1471 }
1472 return ret;
1473 }
1474
1475 static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
1476 enum fib_event_type event_type)
1477 {
1478 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
1479 struct fib_nh_notifier_info info = {
1480 .fib_nh = fib_nh,
1481 };
1482
1483 switch (event_type) {
1484 case FIB_EVENT_NH_ADD:
1485 if (fib_nh->nh_flags & RTNH_F_DEAD)
1486 break;
1487 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1488 fib_nh->nh_flags & RTNH_F_LINKDOWN)
1489 break;
1490 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type,
1491 &info.info);
1492 case FIB_EVENT_NH_DEL:
1493 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1494 fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
1495 (fib_nh->nh_flags & RTNH_F_DEAD))
1496 return call_fib4_notifiers(dev_net(fib_nh->nh_dev),
1497 event_type, &info.info);
1498 default:
1499 break;
1500 }
1501
1502 return NOTIFY_DONE;
1503 }
1504
1505 /* Event force Flags Description
1506 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1507 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1508 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1509 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1510 */
1511 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1512 {
1513 int ret = 0;
1514 int scope = RT_SCOPE_NOWHERE;
1515 struct fib_info *prev_fi = NULL;
1516 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1517 struct hlist_head *head = &fib_info_devhash[hash];
1518 struct fib_nh *nh;
1519
1520 if (force)
1521 scope = -1;
1522
1523 hlist_for_each_entry(nh, head, nh_hash) {
1524 struct fib_info *fi = nh->nh_parent;
1525 int dead;
1526
1527 BUG_ON(!fi->fib_nhs);
1528 if (nh->nh_dev != dev || fi == prev_fi)
1529 continue;
1530 prev_fi = fi;
1531 dead = 0;
1532 change_nexthops(fi) {
1533 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1534 dead++;
1535 else if (nexthop_nh->nh_dev == dev &&
1536 nexthop_nh->nh_scope != scope) {
1537 switch (event) {
1538 case NETDEV_DOWN:
1539 case NETDEV_UNREGISTER:
1540 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1541 /* fall through */
1542 case NETDEV_CHANGE:
1543 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1544 break;
1545 }
1546 call_fib_nh_notifiers(nexthop_nh,
1547 FIB_EVENT_NH_DEL);
1548 dead++;
1549 }
1550 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1551 if (event == NETDEV_UNREGISTER &&
1552 nexthop_nh->nh_dev == dev) {
1553 dead = fi->fib_nhs;
1554 break;
1555 }
1556 #endif
1557 } endfor_nexthops(fi)
1558 if (dead == fi->fib_nhs) {
1559 switch (event) {
1560 case NETDEV_DOWN:
1561 case NETDEV_UNREGISTER:
1562 fi->fib_flags |= RTNH_F_DEAD;
1563 /* fall through */
1564 case NETDEV_CHANGE:
1565 fi->fib_flags |= RTNH_F_LINKDOWN;
1566 break;
1567 }
1568 ret++;
1569 }
1570
1571 fib_rebalance(fi);
1572 }
1573
1574 return ret;
1575 }
1576
1577 /* Must be invoked inside of an RCU protected region. */
1578 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1579 {
1580 struct fib_info *fi = NULL, *last_resort = NULL;
1581 struct hlist_head *fa_head = res->fa_head;
1582 struct fib_table *tb = res->table;
1583 u8 slen = 32 - res->prefixlen;
1584 int order = -1, last_idx = -1;
1585 struct fib_alias *fa, *fa1 = NULL;
1586 u32 last_prio = res->fi->fib_priority;
1587 u8 last_tos = 0;
1588
1589 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1590 struct fib_info *next_fi = fa->fa_info;
1591
1592 if (fa->fa_slen != slen)
1593 continue;
1594 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1595 continue;
1596 if (fa->tb_id != tb->tb_id)
1597 continue;
1598 if (next_fi->fib_priority > last_prio &&
1599 fa->fa_tos == last_tos) {
1600 if (last_tos)
1601 continue;
1602 break;
1603 }
1604 if (next_fi->fib_flags & RTNH_F_DEAD)
1605 continue;
1606 last_tos = fa->fa_tos;
1607 last_prio = next_fi->fib_priority;
1608
1609 if (next_fi->fib_scope != res->scope ||
1610 fa->fa_type != RTN_UNICAST)
1611 continue;
1612 if (!next_fi->fib_nh[0].nh_gw ||
1613 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1614 continue;
1615
1616 fib_alias_accessed(fa);
1617
1618 if (!fi) {
1619 if (next_fi != res->fi)
1620 break;
1621 fa1 = fa;
1622 } else if (!fib_detect_death(fi, order, &last_resort,
1623 &last_idx, fa1->fa_default)) {
1624 fib_result_assign(res, fi);
1625 fa1->fa_default = order;
1626 goto out;
1627 }
1628 fi = next_fi;
1629 order++;
1630 }
1631
1632 if (order <= 0 || !fi) {
1633 if (fa1)
1634 fa1->fa_default = -1;
1635 goto out;
1636 }
1637
1638 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1639 fa1->fa_default)) {
1640 fib_result_assign(res, fi);
1641 fa1->fa_default = order;
1642 goto out;
1643 }
1644
1645 if (last_idx >= 0)
1646 fib_result_assign(res, last_resort);
1647 fa1->fa_default = last_idx;
1648 out:
1649 return;
1650 }
1651
1652 /*
1653 * Dead device goes up. We wake up dead nexthops.
1654 * It takes sense only on multipath routes.
1655 */
1656 int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1657 {
1658 struct fib_info *prev_fi;
1659 unsigned int hash;
1660 struct hlist_head *head;
1661 struct fib_nh *nh;
1662 int ret;
1663
1664 if (!(dev->flags & IFF_UP))
1665 return 0;
1666
1667 if (nh_flags & RTNH_F_DEAD) {
1668 unsigned int flags = dev_get_flags(dev);
1669
1670 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1671 nh_flags |= RTNH_F_LINKDOWN;
1672 }
1673
1674 prev_fi = NULL;
1675 hash = fib_devindex_hashfn(dev->ifindex);
1676 head = &fib_info_devhash[hash];
1677 ret = 0;
1678
1679 hlist_for_each_entry(nh, head, nh_hash) {
1680 struct fib_info *fi = nh->nh_parent;
1681 int alive;
1682
1683 BUG_ON(!fi->fib_nhs);
1684 if (nh->nh_dev != dev || fi == prev_fi)
1685 continue;
1686
1687 prev_fi = fi;
1688 alive = 0;
1689 change_nexthops(fi) {
1690 if (!(nexthop_nh->nh_flags & nh_flags)) {
1691 alive++;
1692 continue;
1693 }
1694 if (!nexthop_nh->nh_dev ||
1695 !(nexthop_nh->nh_dev->flags & IFF_UP))
1696 continue;
1697 if (nexthop_nh->nh_dev != dev ||
1698 !__in_dev_get_rtnl(dev))
1699 continue;
1700 alive++;
1701 nexthop_nh->nh_flags &= ~nh_flags;
1702 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1703 } endfor_nexthops(fi)
1704
1705 if (alive > 0) {
1706 fi->fib_flags &= ~nh_flags;
1707 ret++;
1708 }
1709
1710 fib_rebalance(fi);
1711 }
1712
1713 return ret;
1714 }
1715
1716 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1717 static bool fib_good_nh(const struct fib_nh *nh)
1718 {
1719 int state = NUD_REACHABLE;
1720
1721 if (nh->nh_scope == RT_SCOPE_LINK) {
1722 struct neighbour *n;
1723
1724 rcu_read_lock_bh();
1725
1726 n = __ipv4_neigh_lookup_noref(nh->nh_dev,
1727 (__force u32)nh->nh_gw);
1728 if (n)
1729 state = n->nud_state;
1730
1731 rcu_read_unlock_bh();
1732 }
1733
1734 return !!(state & NUD_VALID);
1735 }
1736
1737 void fib_select_multipath(struct fib_result *res, int hash)
1738 {
1739 struct fib_info *fi = res->fi;
1740 struct net *net = fi->fib_net;
1741 bool first = false;
1742
1743 for_nexthops(fi) {
1744 if (hash > atomic_read(&nh->nh_upper_bound))
1745 continue;
1746
1747 if (!net->ipv4.sysctl_fib_multipath_use_neigh ||
1748 fib_good_nh(nh)) {
1749 res->nh_sel = nhsel;
1750 return;
1751 }
1752 if (!first) {
1753 res->nh_sel = nhsel;
1754 first = true;
1755 }
1756 } endfor_nexthops(fi);
1757 }
1758 #endif
1759
1760 void fib_select_path(struct net *net, struct fib_result *res,
1761 struct flowi4 *fl4, const struct sk_buff *skb)
1762 {
1763 bool oif_check;
1764
1765 oif_check = (fl4->flowi4_oif == 0 ||
1766 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
1767
1768 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1769 if (res->fi->fib_nhs > 1 && oif_check) {
1770 int h = fib_multipath_hash(res->fi, fl4, skb);
1771
1772 fib_select_multipath(res, h);
1773 }
1774 else
1775 #endif
1776 if (!res->prefixlen &&
1777 res->table->tb_num_default > 1 &&
1778 res->type == RTN_UNICAST && oif_check)
1779 fib_select_default(fl4, res);
1780
1781 if (!fl4->saddr)
1782 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1783 }
1784 EXPORT_SYMBOL_GPL(fib_select_path);
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