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1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * IPv4 Forwarding Information Base: semantics.
7 *
8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16 #include <linux/uaccess.h>
17 #include <linux/bitops.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/jiffies.h>
21 #include <linux/mm.h>
22 #include <linux/string.h>
23 #include <linux/socket.h>
24 #include <linux/sockios.h>
25 #include <linux/errno.h>
26 #include <linux/in.h>
27 #include <linux/inet.h>
28 #include <linux/inetdevice.h>
29 #include <linux/netdevice.h>
30 #include <linux/if_arp.h>
31 #include <linux/proc_fs.h>
32 #include <linux/skbuff.h>
33 #include <linux/init.h>
34 #include <linux/slab.h>
35 #include <linux/netlink.h>
36
37 #include <net/arp.h>
38 #include <net/ip.h>
39 #include <net/protocol.h>
40 #include <net/route.h>
41 #include <net/tcp.h>
42 #include <net/sock.h>
43 #include <net/ip_fib.h>
44 #include <net/netlink.h>
45 #include <net/nexthop.h>
46 #include <net/lwtunnel.h>
47
48 #include "fib_lookup.h"
49
50 static DEFINE_SPINLOCK(fib_info_lock);
51 static struct hlist_head *fib_info_hash;
52 static struct hlist_head *fib_info_laddrhash;
53 static unsigned int fib_info_hash_size;
54 static unsigned int fib_info_cnt;
55
56 #define DEVINDEX_HASHBITS 8
57 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
58 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
59
60 #ifdef CONFIG_IP_ROUTE_MULTIPATH
61
62 #define for_nexthops(fi) { \
63 int nhsel; const struct fib_nh *nh; \
64 for (nhsel = 0, nh = (fi)->fib_nh; \
65 nhsel < (fi)->fib_nhs; \
66 nh++, nhsel++)
67
68 #define change_nexthops(fi) { \
69 int nhsel; struct fib_nh *nexthop_nh; \
70 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
71 nhsel < (fi)->fib_nhs; \
72 nexthop_nh++, nhsel++)
73
74 #else /* CONFIG_IP_ROUTE_MULTIPATH */
75
76 /* Hope, that gcc will optimize it to get rid of dummy loop */
77
78 #define for_nexthops(fi) { \
79 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
80 for (nhsel = 0; nhsel < 1; nhsel++)
81
82 #define change_nexthops(fi) { \
83 int nhsel; \
84 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
88
89 #define endfor_nexthops(fi) }
90
91
92 const struct fib_prop fib_props[RTN_MAX + 1] = {
93 [RTN_UNSPEC] = {
94 .error = 0,
95 .scope = RT_SCOPE_NOWHERE,
96 },
97 [RTN_UNICAST] = {
98 .error = 0,
99 .scope = RT_SCOPE_UNIVERSE,
100 },
101 [RTN_LOCAL] = {
102 .error = 0,
103 .scope = RT_SCOPE_HOST,
104 },
105 [RTN_BROADCAST] = {
106 .error = 0,
107 .scope = RT_SCOPE_LINK,
108 },
109 [RTN_ANYCAST] = {
110 .error = 0,
111 .scope = RT_SCOPE_LINK,
112 },
113 [RTN_MULTICAST] = {
114 .error = 0,
115 .scope = RT_SCOPE_UNIVERSE,
116 },
117 [RTN_BLACKHOLE] = {
118 .error = -EINVAL,
119 .scope = RT_SCOPE_UNIVERSE,
120 },
121 [RTN_UNREACHABLE] = {
122 .error = -EHOSTUNREACH,
123 .scope = RT_SCOPE_UNIVERSE,
124 },
125 [RTN_PROHIBIT] = {
126 .error = -EACCES,
127 .scope = RT_SCOPE_UNIVERSE,
128 },
129 [RTN_THROW] = {
130 .error = -EAGAIN,
131 .scope = RT_SCOPE_UNIVERSE,
132 },
133 [RTN_NAT] = {
134 .error = -EINVAL,
135 .scope = RT_SCOPE_NOWHERE,
136 },
137 [RTN_XRESOLVE] = {
138 .error = -EINVAL,
139 .scope = RT_SCOPE_NOWHERE,
140 },
141 };
142
143 static void rt_fibinfo_free(struct rtable __rcu **rtp)
144 {
145 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
146
147 if (!rt)
148 return;
149
150 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
151 * because we waited an RCU grace period before calling
152 * free_fib_info_rcu()
153 */
154
155 dst_dev_put(&rt->dst);
156 dst_release_immediate(&rt->dst);
157 }
158
159 static void free_nh_exceptions(struct fib_nh *nh)
160 {
161 struct fnhe_hash_bucket *hash;
162 int i;
163
164 hash = rcu_dereference_protected(nh->nh_exceptions, 1);
165 if (!hash)
166 return;
167 for (i = 0; i < FNHE_HASH_SIZE; i++) {
168 struct fib_nh_exception *fnhe;
169
170 fnhe = rcu_dereference_protected(hash[i].chain, 1);
171 while (fnhe) {
172 struct fib_nh_exception *next;
173
174 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
175
176 rt_fibinfo_free(&fnhe->fnhe_rth_input);
177 rt_fibinfo_free(&fnhe->fnhe_rth_output);
178
179 kfree(fnhe);
180
181 fnhe = next;
182 }
183 }
184 kfree(hash);
185 }
186
187 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
188 {
189 int cpu;
190
191 if (!rtp)
192 return;
193
194 for_each_possible_cpu(cpu) {
195 struct rtable *rt;
196
197 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
198 if (rt) {
199 dst_dev_put(&rt->dst);
200 dst_release_immediate(&rt->dst);
201 }
202 }
203 free_percpu(rtp);
204 }
205
206 /* Release a nexthop info record */
207 static void free_fib_info_rcu(struct rcu_head *head)
208 {
209 struct fib_info *fi = container_of(head, struct fib_info, rcu);
210 struct dst_metrics *m;
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 m = fi->fib_metrics;
222 if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt))
223 kfree(m);
224 kfree(fi);
225 }
226
227 void free_fib_info(struct fib_info *fi)
228 {
229 if (fi->fib_dead == 0) {
230 pr_warn("Freeing alive fib_info %p\n", fi);
231 return;
232 }
233 fib_info_cnt--;
234 #ifdef CONFIG_IP_ROUTE_CLASSID
235 change_nexthops(fi) {
236 if (nexthop_nh->nh_tclassid)
237 fi->fib_net->ipv4.fib_num_tclassid_users--;
238 } endfor_nexthops(fi);
239 #endif
240 call_rcu(&fi->rcu, free_fib_info_rcu);
241 }
242 EXPORT_SYMBOL_GPL(free_fib_info);
243
244 void fib_release_info(struct fib_info *fi)
245 {
246 spin_lock_bh(&fib_info_lock);
247 if (fi && --fi->fib_treeref == 0) {
248 hlist_del(&fi->fib_hash);
249 if (fi->fib_prefsrc)
250 hlist_del(&fi->fib_lhash);
251 change_nexthops(fi) {
252 if (!nexthop_nh->nh_dev)
253 continue;
254 hlist_del(&nexthop_nh->nh_hash);
255 } endfor_nexthops(fi)
256 fi->fib_dead = 1;
257 fib_info_put(fi);
258 }
259 spin_unlock_bh(&fib_info_lock);
260 }
261
262 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
263 {
264 const struct fib_nh *onh = ofi->fib_nh;
265
266 for_nexthops(fi) {
267 if (nh->nh_oif != onh->nh_oif ||
268 nh->nh_gw != onh->nh_gw ||
269 nh->nh_scope != onh->nh_scope ||
270 #ifdef CONFIG_IP_ROUTE_MULTIPATH
271 nh->nh_weight != onh->nh_weight ||
272 #endif
273 #ifdef CONFIG_IP_ROUTE_CLASSID
274 nh->nh_tclassid != onh->nh_tclassid ||
275 #endif
276 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
277 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
278 return -1;
279 onh++;
280 } endfor_nexthops(fi);
281 return 0;
282 }
283
284 static inline unsigned int fib_devindex_hashfn(unsigned int val)
285 {
286 unsigned int mask = DEVINDEX_HASHSIZE - 1;
287
288 return (val ^
289 (val >> DEVINDEX_HASHBITS) ^
290 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
291 }
292
293 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
294 {
295 unsigned int mask = (fib_info_hash_size - 1);
296 unsigned int val = fi->fib_nhs;
297
298 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
299 val ^= (__force u32)fi->fib_prefsrc;
300 val ^= fi->fib_priority;
301 for_nexthops(fi) {
302 val ^= fib_devindex_hashfn(nh->nh_oif);
303 } endfor_nexthops(fi)
304
305 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
306 }
307
308 static struct fib_info *fib_find_info(const struct fib_info *nfi)
309 {
310 struct hlist_head *head;
311 struct fib_info *fi;
312 unsigned int hash;
313
314 hash = fib_info_hashfn(nfi);
315 head = &fib_info_hash[hash];
316
317 hlist_for_each_entry(fi, head, fib_hash) {
318 if (!net_eq(fi->fib_net, nfi->fib_net))
319 continue;
320 if (fi->fib_nhs != nfi->fib_nhs)
321 continue;
322 if (nfi->fib_protocol == fi->fib_protocol &&
323 nfi->fib_scope == fi->fib_scope &&
324 nfi->fib_prefsrc == fi->fib_prefsrc &&
325 nfi->fib_priority == fi->fib_priority &&
326 nfi->fib_type == fi->fib_type &&
327 memcmp(nfi->fib_metrics, fi->fib_metrics,
328 sizeof(u32) * RTAX_MAX) == 0 &&
329 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
330 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
331 return fi;
332 }
333
334 return NULL;
335 }
336
337 /* Check, that the gateway is already configured.
338 * Used only by redirect accept routine.
339 */
340 int ip_fib_check_default(__be32 gw, struct net_device *dev)
341 {
342 struct hlist_head *head;
343 struct fib_nh *nh;
344 unsigned int hash;
345
346 spin_lock(&fib_info_lock);
347
348 hash = fib_devindex_hashfn(dev->ifindex);
349 head = &fib_info_devhash[hash];
350 hlist_for_each_entry(nh, head, nh_hash) {
351 if (nh->nh_dev == dev &&
352 nh->nh_gw == gw &&
353 !(nh->nh_flags & RTNH_F_DEAD)) {
354 spin_unlock(&fib_info_lock);
355 return 0;
356 }
357 }
358
359 spin_unlock(&fib_info_lock);
360
361 return -1;
362 }
363
364 static inline size_t fib_nlmsg_size(struct fib_info *fi)
365 {
366 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
367 + nla_total_size(4) /* RTA_TABLE */
368 + nla_total_size(4) /* RTA_DST */
369 + nla_total_size(4) /* RTA_PRIORITY */
370 + nla_total_size(4) /* RTA_PREFSRC */
371 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
372
373 /* space for nested metrics */
374 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
375
376 if (fi->fib_nhs) {
377 size_t nh_encapsize = 0;
378 /* Also handles the special case fib_nhs == 1 */
379
380 /* each nexthop is packed in an attribute */
381 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
382
383 /* may contain flow and gateway attribute */
384 nhsize += 2 * nla_total_size(4);
385
386 /* grab encap info */
387 for_nexthops(fi) {
388 if (nh->nh_lwtstate) {
389 /* RTA_ENCAP_TYPE */
390 nh_encapsize += lwtunnel_get_encap_size(
391 nh->nh_lwtstate);
392 /* RTA_ENCAP */
393 nh_encapsize += nla_total_size(2);
394 }
395 } endfor_nexthops(fi);
396
397 /* all nexthops are packed in a nested attribute */
398 payload += nla_total_size((fi->fib_nhs * nhsize) +
399 nh_encapsize);
400
401 }
402
403 return payload;
404 }
405
406 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
407 int dst_len, u32 tb_id, const struct nl_info *info,
408 unsigned int nlm_flags)
409 {
410 struct sk_buff *skb;
411 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
412 int err = -ENOBUFS;
413
414 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
415 if (!skb)
416 goto errout;
417
418 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
419 fa->fa_type, key, dst_len,
420 fa->fa_tos, fa->fa_info, nlm_flags);
421 if (err < 0) {
422 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
423 WARN_ON(err == -EMSGSIZE);
424 kfree_skb(skb);
425 goto errout;
426 }
427 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
428 info->nlh, GFP_KERNEL);
429 return;
430 errout:
431 if (err < 0)
432 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
433 }
434
435 static int fib_detect_death(struct fib_info *fi, int order,
436 struct fib_info **last_resort, int *last_idx,
437 int dflt)
438 {
439 struct neighbour *n;
440 int state = NUD_NONE;
441
442 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
443 if (n) {
444 state = n->nud_state;
445 neigh_release(n);
446 } else {
447 return 0;
448 }
449 if (state == NUD_REACHABLE)
450 return 0;
451 if ((state & NUD_VALID) && order != dflt)
452 return 0;
453 if ((state & NUD_VALID) ||
454 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
455 *last_resort = fi;
456 *last_idx = order;
457 }
458 return 1;
459 }
460
461 #ifdef CONFIG_IP_ROUTE_MULTIPATH
462
463 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
464 struct netlink_ext_ack *extack)
465 {
466 int nhs = 0;
467
468 while (rtnh_ok(rtnh, remaining)) {
469 nhs++;
470 rtnh = rtnh_next(rtnh, &remaining);
471 }
472
473 /* leftover implies invalid nexthop configuration, discard it */
474 if (remaining > 0) {
475 NL_SET_ERR_MSG(extack,
476 "Invalid nexthop configuration - extra data after nexthops");
477 nhs = 0;
478 }
479
480 return nhs;
481 }
482
483 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
484 int remaining, struct fib_config *cfg,
485 struct netlink_ext_ack *extack)
486 {
487 int ret;
488
489 change_nexthops(fi) {
490 int attrlen;
491
492 if (!rtnh_ok(rtnh, remaining)) {
493 NL_SET_ERR_MSG(extack,
494 "Invalid nexthop configuration - extra data after nexthop");
495 return -EINVAL;
496 }
497
498 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
499 NL_SET_ERR_MSG(extack,
500 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
501 return -EINVAL;
502 }
503
504 nexthop_nh->nh_flags =
505 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
506 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
507 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
508
509 attrlen = rtnh_attrlen(rtnh);
510 if (attrlen > 0) {
511 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
512
513 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
514 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
515 #ifdef CONFIG_IP_ROUTE_CLASSID
516 nla = nla_find(attrs, attrlen, RTA_FLOW);
517 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
518 if (nexthop_nh->nh_tclassid)
519 fi->fib_net->ipv4.fib_num_tclassid_users++;
520 #endif
521 nla = nla_find(attrs, attrlen, RTA_ENCAP);
522 if (nla) {
523 struct lwtunnel_state *lwtstate;
524 struct nlattr *nla_entype;
525
526 nla_entype = nla_find(attrs, attrlen,
527 RTA_ENCAP_TYPE);
528 if (!nla_entype) {
529 NL_SET_BAD_ATTR(extack, nla);
530 NL_SET_ERR_MSG(extack,
531 "Encap type is missing");
532 goto err_inval;
533 }
534
535 ret = lwtunnel_build_state(nla_get_u16(
536 nla_entype),
537 nla, AF_INET, cfg,
538 &lwtstate, extack);
539 if (ret)
540 goto errout;
541 nexthop_nh->nh_lwtstate =
542 lwtstate_get(lwtstate);
543 }
544 }
545
546 rtnh = rtnh_next(rtnh, &remaining);
547 } endfor_nexthops(fi);
548
549 return 0;
550
551 err_inval:
552 ret = -EINVAL;
553
554 errout:
555 return ret;
556 }
557
558 static void fib_rebalance(struct fib_info *fi)
559 {
560 int total;
561 int w;
562 struct in_device *in_dev;
563
564 if (fi->fib_nhs < 2)
565 return;
566
567 total = 0;
568 for_nexthops(fi) {
569 if (nh->nh_flags & RTNH_F_DEAD)
570 continue;
571
572 in_dev = __in_dev_get_rtnl(nh->nh_dev);
573
574 if (in_dev &&
575 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
576 nh->nh_flags & RTNH_F_LINKDOWN)
577 continue;
578
579 total += nh->nh_weight;
580 } endfor_nexthops(fi);
581
582 w = 0;
583 change_nexthops(fi) {
584 int upper_bound;
585
586 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
587
588 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
589 upper_bound = -1;
590 } else if (in_dev &&
591 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
592 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
593 upper_bound = -1;
594 } else {
595 w += nexthop_nh->nh_weight;
596 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
597 total) - 1;
598 }
599
600 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
601 } endfor_nexthops(fi);
602 }
603
604 static inline void fib_add_weight(struct fib_info *fi,
605 const struct fib_nh *nh)
606 {
607 fi->fib_weight += nh->nh_weight;
608 }
609
610 #else /* CONFIG_IP_ROUTE_MULTIPATH */
611
612 #define fib_rebalance(fi) do { } while (0)
613 #define fib_add_weight(fi, nh) do { } while (0)
614
615 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
616
617 static int fib_encap_match(u16 encap_type,
618 struct nlattr *encap,
619 const struct fib_nh *nh,
620 const struct fib_config *cfg,
621 struct netlink_ext_ack *extack)
622 {
623 struct lwtunnel_state *lwtstate;
624 int ret, result = 0;
625
626 if (encap_type == LWTUNNEL_ENCAP_NONE)
627 return 0;
628
629 ret = lwtunnel_build_state(encap_type, encap, AF_INET,
630 cfg, &lwtstate, extack);
631 if (!ret) {
632 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
633 lwtstate_free(lwtstate);
634 }
635
636 return result;
637 }
638
639 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
640 struct netlink_ext_ack *extack)
641 {
642 #ifdef CONFIG_IP_ROUTE_MULTIPATH
643 struct rtnexthop *rtnh;
644 int remaining;
645 #endif
646
647 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
648 return 1;
649
650 if (cfg->fc_oif || cfg->fc_gw) {
651 if (cfg->fc_encap) {
652 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
653 fi->fib_nh, cfg, extack))
654 return 1;
655 }
656 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
657 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
658 return 0;
659 return 1;
660 }
661
662 #ifdef CONFIG_IP_ROUTE_MULTIPATH
663 if (!cfg->fc_mp)
664 return 0;
665
666 rtnh = cfg->fc_mp;
667 remaining = cfg->fc_mp_len;
668
669 for_nexthops(fi) {
670 int attrlen;
671
672 if (!rtnh_ok(rtnh, remaining))
673 return -EINVAL;
674
675 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
676 return 1;
677
678 attrlen = rtnh_attrlen(rtnh);
679 if (attrlen > 0) {
680 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
681
682 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
683 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
684 return 1;
685 #ifdef CONFIG_IP_ROUTE_CLASSID
686 nla = nla_find(attrs, attrlen, RTA_FLOW);
687 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
688 return 1;
689 #endif
690 }
691
692 rtnh = rtnh_next(rtnh, &remaining);
693 } endfor_nexthops(fi);
694 #endif
695 return 0;
696 }
697
698
699 /*
700 * Picture
701 * -------
702 *
703 * Semantics of nexthop is very messy by historical reasons.
704 * We have to take into account, that:
705 * a) gateway can be actually local interface address,
706 * so that gatewayed route is direct.
707 * b) gateway must be on-link address, possibly
708 * described not by an ifaddr, but also by a direct route.
709 * c) If both gateway and interface are specified, they should not
710 * contradict.
711 * d) If we use tunnel routes, gateway could be not on-link.
712 *
713 * Attempt to reconcile all of these (alas, self-contradictory) conditions
714 * results in pretty ugly and hairy code with obscure logic.
715 *
716 * I chose to generalized it instead, so that the size
717 * of code does not increase practically, but it becomes
718 * much more general.
719 * Every prefix is assigned a "scope" value: "host" is local address,
720 * "link" is direct route,
721 * [ ... "site" ... "interior" ... ]
722 * and "universe" is true gateway route with global meaning.
723 *
724 * Every prefix refers to a set of "nexthop"s (gw, oif),
725 * where gw must have narrower scope. This recursion stops
726 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
727 * which means that gw is forced to be on link.
728 *
729 * Code is still hairy, but now it is apparently logically
730 * consistent and very flexible. F.e. as by-product it allows
731 * to co-exists in peace independent exterior and interior
732 * routing processes.
733 *
734 * Normally it looks as following.
735 *
736 * {universe prefix} -> (gw, oif) [scope link]
737 * |
738 * |-> {link prefix} -> (gw, oif) [scope local]
739 * |
740 * |-> {local prefix} (terminal node)
741 */
742 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
743 struct fib_nh *nh, struct netlink_ext_ack *extack)
744 {
745 int err = 0;
746 struct net *net;
747 struct net_device *dev;
748
749 net = cfg->fc_nlinfo.nl_net;
750 if (nh->nh_gw) {
751 struct fib_result res;
752
753 if (nh->nh_flags & RTNH_F_ONLINK) {
754 unsigned int addr_type;
755
756 if (cfg->fc_scope >= RT_SCOPE_LINK) {
757 NL_SET_ERR_MSG(extack,
758 "Nexthop has invalid scope");
759 return -EINVAL;
760 }
761 dev = __dev_get_by_index(net, nh->nh_oif);
762 if (!dev)
763 return -ENODEV;
764 if (!(dev->flags & IFF_UP)) {
765 NL_SET_ERR_MSG(extack,
766 "Nexthop device is not up");
767 return -ENETDOWN;
768 }
769 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
770 if (addr_type != RTN_UNICAST) {
771 NL_SET_ERR_MSG(extack,
772 "Nexthop has invalid gateway");
773 return -EINVAL;
774 }
775 if (!netif_carrier_ok(dev))
776 nh->nh_flags |= RTNH_F_LINKDOWN;
777 nh->nh_dev = dev;
778 dev_hold(dev);
779 nh->nh_scope = RT_SCOPE_LINK;
780 return 0;
781 }
782 rcu_read_lock();
783 {
784 struct fib_table *tbl = NULL;
785 struct flowi4 fl4 = {
786 .daddr = nh->nh_gw,
787 .flowi4_scope = cfg->fc_scope + 1,
788 .flowi4_oif = nh->nh_oif,
789 .flowi4_iif = LOOPBACK_IFINDEX,
790 };
791
792 /* It is not necessary, but requires a bit of thinking */
793 if (fl4.flowi4_scope < RT_SCOPE_LINK)
794 fl4.flowi4_scope = RT_SCOPE_LINK;
795
796 if (cfg->fc_table)
797 tbl = fib_get_table(net, cfg->fc_table);
798
799 if (tbl)
800 err = fib_table_lookup(tbl, &fl4, &res,
801 FIB_LOOKUP_IGNORE_LINKSTATE |
802 FIB_LOOKUP_NOREF);
803
804 /* on error or if no table given do full lookup. This
805 * is needed for example when nexthops are in the local
806 * table rather than the given table
807 */
808 if (!tbl || err) {
809 err = fib_lookup(net, &fl4, &res,
810 FIB_LOOKUP_IGNORE_LINKSTATE);
811 }
812
813 if (err) {
814 NL_SET_ERR_MSG(extack,
815 "Nexthop has invalid gateway");
816 rcu_read_unlock();
817 return err;
818 }
819 }
820 err = -EINVAL;
821 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
822 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
823 goto out;
824 }
825 nh->nh_scope = res.scope;
826 nh->nh_oif = FIB_RES_OIF(res);
827 nh->nh_dev = dev = FIB_RES_DEV(res);
828 if (!dev) {
829 NL_SET_ERR_MSG(extack,
830 "No egress device for nexthop gateway");
831 goto out;
832 }
833 dev_hold(dev);
834 if (!netif_carrier_ok(dev))
835 nh->nh_flags |= RTNH_F_LINKDOWN;
836 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
837 } else {
838 struct in_device *in_dev;
839
840 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
841 NL_SET_ERR_MSG(extack,
842 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
843 return -EINVAL;
844 }
845 rcu_read_lock();
846 err = -ENODEV;
847 in_dev = inetdev_by_index(net, nh->nh_oif);
848 if (!in_dev)
849 goto out;
850 err = -ENETDOWN;
851 if (!(in_dev->dev->flags & IFF_UP)) {
852 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
853 goto out;
854 }
855 nh->nh_dev = in_dev->dev;
856 dev_hold(nh->nh_dev);
857 nh->nh_scope = RT_SCOPE_HOST;
858 if (!netif_carrier_ok(nh->nh_dev))
859 nh->nh_flags |= RTNH_F_LINKDOWN;
860 err = 0;
861 }
862 out:
863 rcu_read_unlock();
864 return err;
865 }
866
867 static inline unsigned int fib_laddr_hashfn(__be32 val)
868 {
869 unsigned int mask = (fib_info_hash_size - 1);
870
871 return ((__force u32)val ^
872 ((__force u32)val >> 7) ^
873 ((__force u32)val >> 14)) & mask;
874 }
875
876 static struct hlist_head *fib_info_hash_alloc(int bytes)
877 {
878 if (bytes <= PAGE_SIZE)
879 return kzalloc(bytes, GFP_KERNEL);
880 else
881 return (struct hlist_head *)
882 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
883 get_order(bytes));
884 }
885
886 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
887 {
888 if (!hash)
889 return;
890
891 if (bytes <= PAGE_SIZE)
892 kfree(hash);
893 else
894 free_pages((unsigned long) hash, get_order(bytes));
895 }
896
897 static void fib_info_hash_move(struct hlist_head *new_info_hash,
898 struct hlist_head *new_laddrhash,
899 unsigned int new_size)
900 {
901 struct hlist_head *old_info_hash, *old_laddrhash;
902 unsigned int old_size = fib_info_hash_size;
903 unsigned int i, bytes;
904
905 spin_lock_bh(&fib_info_lock);
906 old_info_hash = fib_info_hash;
907 old_laddrhash = fib_info_laddrhash;
908 fib_info_hash_size = new_size;
909
910 for (i = 0; i < old_size; i++) {
911 struct hlist_head *head = &fib_info_hash[i];
912 struct hlist_node *n;
913 struct fib_info *fi;
914
915 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
916 struct hlist_head *dest;
917 unsigned int new_hash;
918
919 new_hash = fib_info_hashfn(fi);
920 dest = &new_info_hash[new_hash];
921 hlist_add_head(&fi->fib_hash, dest);
922 }
923 }
924 fib_info_hash = new_info_hash;
925
926 for (i = 0; i < old_size; i++) {
927 struct hlist_head *lhead = &fib_info_laddrhash[i];
928 struct hlist_node *n;
929 struct fib_info *fi;
930
931 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
932 struct hlist_head *ldest;
933 unsigned int new_hash;
934
935 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
936 ldest = &new_laddrhash[new_hash];
937 hlist_add_head(&fi->fib_lhash, ldest);
938 }
939 }
940 fib_info_laddrhash = new_laddrhash;
941
942 spin_unlock_bh(&fib_info_lock);
943
944 bytes = old_size * sizeof(struct hlist_head *);
945 fib_info_hash_free(old_info_hash, bytes);
946 fib_info_hash_free(old_laddrhash, bytes);
947 }
948
949 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
950 {
951 nh->nh_saddr = inet_select_addr(nh->nh_dev,
952 nh->nh_gw,
953 nh->nh_parent->fib_scope);
954 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
955
956 return nh->nh_saddr;
957 }
958
959 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
960 {
961 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
962 fib_prefsrc != cfg->fc_dst) {
963 u32 tb_id = cfg->fc_table;
964 int rc;
965
966 if (tb_id == RT_TABLE_MAIN)
967 tb_id = RT_TABLE_LOCAL;
968
969 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
970 fib_prefsrc, tb_id);
971
972 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
973 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
974 fib_prefsrc, RT_TABLE_LOCAL);
975 }
976
977 if (rc != RTN_LOCAL)
978 return false;
979 }
980 return true;
981 }
982
983 static int
984 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
985 {
986 bool ecn_ca = false;
987 struct nlattr *nla;
988 int remaining;
989
990 if (!cfg->fc_mx)
991 return 0;
992
993 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
994 int type = nla_type(nla);
995 u32 val;
996
997 if (!type)
998 continue;
999 if (type > RTAX_MAX)
1000 return -EINVAL;
1001
1002 if (type == RTAX_CC_ALGO) {
1003 char tmp[TCP_CA_NAME_MAX];
1004
1005 nla_strlcpy(tmp, nla, sizeof(tmp));
1006 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
1007 if (val == TCP_CA_UNSPEC)
1008 return -EINVAL;
1009 } else {
1010 val = nla_get_u32(nla);
1011 }
1012 if (type == RTAX_ADVMSS && val > 65535 - 40)
1013 val = 65535 - 40;
1014 if (type == RTAX_MTU && val > 65535 - 15)
1015 val = 65535 - 15;
1016 if (type == RTAX_HOPLIMIT && val > 255)
1017 val = 255;
1018 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
1019 return -EINVAL;
1020 fi->fib_metrics->metrics[type - 1] = val;
1021 }
1022
1023 if (ecn_ca)
1024 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
1025
1026 return 0;
1027 }
1028
1029 struct fib_info *fib_create_info(struct fib_config *cfg,
1030 struct netlink_ext_ack *extack)
1031 {
1032 int err;
1033 struct fib_info *fi = NULL;
1034 struct fib_info *ofi;
1035 int nhs = 1;
1036 struct net *net = cfg->fc_nlinfo.nl_net;
1037
1038 if (cfg->fc_type > RTN_MAX)
1039 goto err_inval;
1040
1041 /* Fast check to catch the most weird cases */
1042 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1043 NL_SET_ERR_MSG(extack, "Invalid scope");
1044 goto err_inval;
1045 }
1046
1047 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1048 NL_SET_ERR_MSG(extack,
1049 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1050 goto err_inval;
1051 }
1052
1053 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1054 if (cfg->fc_mp) {
1055 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1056 if (nhs == 0)
1057 goto err_inval;
1058 }
1059 #endif
1060
1061 err = -ENOBUFS;
1062 if (fib_info_cnt >= fib_info_hash_size) {
1063 unsigned int new_size = fib_info_hash_size << 1;
1064 struct hlist_head *new_info_hash;
1065 struct hlist_head *new_laddrhash;
1066 unsigned int bytes;
1067
1068 if (!new_size)
1069 new_size = 16;
1070 bytes = new_size * sizeof(struct hlist_head *);
1071 new_info_hash = fib_info_hash_alloc(bytes);
1072 new_laddrhash = fib_info_hash_alloc(bytes);
1073 if (!new_info_hash || !new_laddrhash) {
1074 fib_info_hash_free(new_info_hash, bytes);
1075 fib_info_hash_free(new_laddrhash, bytes);
1076 } else
1077 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1078
1079 if (!fib_info_hash_size)
1080 goto failure;
1081 }
1082
1083 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1084 if (!fi)
1085 goto failure;
1086 if (cfg->fc_mx) {
1087 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
1088 if (unlikely(!fi->fib_metrics)) {
1089 kfree(fi);
1090 return ERR_PTR(err);
1091 }
1092 atomic_set(&fi->fib_metrics->refcnt, 1);
1093 } else {
1094 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
1095 }
1096 fib_info_cnt++;
1097 fi->fib_net = net;
1098 fi->fib_protocol = cfg->fc_protocol;
1099 fi->fib_scope = cfg->fc_scope;
1100 fi->fib_flags = cfg->fc_flags;
1101 fi->fib_priority = cfg->fc_priority;
1102 fi->fib_prefsrc = cfg->fc_prefsrc;
1103 fi->fib_type = cfg->fc_type;
1104 fi->fib_tb_id = cfg->fc_table;
1105
1106 fi->fib_nhs = nhs;
1107 change_nexthops(fi) {
1108 nexthop_nh->nh_parent = fi;
1109 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1110 if (!nexthop_nh->nh_pcpu_rth_output)
1111 goto failure;
1112 } endfor_nexthops(fi)
1113
1114 err = fib_convert_metrics(fi, cfg);
1115 if (err)
1116 goto failure;
1117
1118 if (cfg->fc_mp) {
1119 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1120 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1121 if (err != 0)
1122 goto failure;
1123 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
1124 NL_SET_ERR_MSG(extack,
1125 "Nexthop device index does not match RTA_OIF");
1126 goto err_inval;
1127 }
1128 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
1129 NL_SET_ERR_MSG(extack,
1130 "Nexthop gateway does not match RTA_GATEWAY");
1131 goto err_inval;
1132 }
1133 #ifdef CONFIG_IP_ROUTE_CLASSID
1134 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
1135 NL_SET_ERR_MSG(extack,
1136 "Nexthop class id does not match RTA_FLOW");
1137 goto err_inval;
1138 }
1139 #endif
1140 #else
1141 NL_SET_ERR_MSG(extack,
1142 "Multipath support not enabled in kernel");
1143 goto err_inval;
1144 #endif
1145 } else {
1146 struct fib_nh *nh = fi->fib_nh;
1147
1148 if (cfg->fc_encap) {
1149 struct lwtunnel_state *lwtstate;
1150
1151 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
1152 NL_SET_ERR_MSG(extack,
1153 "LWT encap type not specified");
1154 goto err_inval;
1155 }
1156 err = lwtunnel_build_state(cfg->fc_encap_type,
1157 cfg->fc_encap, AF_INET, cfg,
1158 &lwtstate, extack);
1159 if (err)
1160 goto failure;
1161
1162 nh->nh_lwtstate = lwtstate_get(lwtstate);
1163 }
1164 nh->nh_oif = cfg->fc_oif;
1165 nh->nh_gw = cfg->fc_gw;
1166 nh->nh_flags = cfg->fc_flags;
1167 #ifdef CONFIG_IP_ROUTE_CLASSID
1168 nh->nh_tclassid = cfg->fc_flow;
1169 if (nh->nh_tclassid)
1170 fi->fib_net->ipv4.fib_num_tclassid_users++;
1171 #endif
1172 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1173 nh->nh_weight = 1;
1174 #endif
1175 }
1176
1177 if (fib_props[cfg->fc_type].error) {
1178 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) {
1179 NL_SET_ERR_MSG(extack,
1180 "Gateway, device and multipath can not be specified for this route type");
1181 goto err_inval;
1182 }
1183 goto link_it;
1184 } else {
1185 switch (cfg->fc_type) {
1186 case RTN_UNICAST:
1187 case RTN_LOCAL:
1188 case RTN_BROADCAST:
1189 case RTN_ANYCAST:
1190 case RTN_MULTICAST:
1191 break;
1192 default:
1193 NL_SET_ERR_MSG(extack, "Invalid route type");
1194 goto err_inval;
1195 }
1196 }
1197
1198 if (cfg->fc_scope > RT_SCOPE_HOST) {
1199 NL_SET_ERR_MSG(extack, "Invalid scope");
1200 goto err_inval;
1201 }
1202
1203 if (cfg->fc_scope == RT_SCOPE_HOST) {
1204 struct fib_nh *nh = fi->fib_nh;
1205
1206 /* Local address is added. */
1207 if (nhs != 1) {
1208 NL_SET_ERR_MSG(extack,
1209 "Route with host scope can not have multiple nexthops");
1210 goto err_inval;
1211 }
1212 if (nh->nh_gw) {
1213 NL_SET_ERR_MSG(extack,
1214 "Route with host scope can not have a gateway");
1215 goto err_inval;
1216 }
1217 nh->nh_scope = RT_SCOPE_NOWHERE;
1218 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1219 err = -ENODEV;
1220 if (!nh->nh_dev)
1221 goto failure;
1222 } else {
1223 int linkdown = 0;
1224
1225 change_nexthops(fi) {
1226 err = fib_check_nh(cfg, fi, nexthop_nh, extack);
1227 if (err != 0)
1228 goto failure;
1229 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1230 linkdown++;
1231 } endfor_nexthops(fi)
1232 if (linkdown == fi->fib_nhs)
1233 fi->fib_flags |= RTNH_F_LINKDOWN;
1234 }
1235
1236 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1237 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1238 goto err_inval;
1239 }
1240
1241 change_nexthops(fi) {
1242 fib_info_update_nh_saddr(net, nexthop_nh);
1243 fib_add_weight(fi, nexthop_nh);
1244 } endfor_nexthops(fi)
1245
1246 fib_rebalance(fi);
1247
1248 link_it:
1249 ofi = fib_find_info(fi);
1250 if (ofi) {
1251 fi->fib_dead = 1;
1252 free_fib_info(fi);
1253 ofi->fib_treeref++;
1254 return ofi;
1255 }
1256
1257 fi->fib_treeref++;
1258 refcount_set(&fi->fib_clntref, 1);
1259 spin_lock_bh(&fib_info_lock);
1260 hlist_add_head(&fi->fib_hash,
1261 &fib_info_hash[fib_info_hashfn(fi)]);
1262 if (fi->fib_prefsrc) {
1263 struct hlist_head *head;
1264
1265 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1266 hlist_add_head(&fi->fib_lhash, head);
1267 }
1268 change_nexthops(fi) {
1269 struct hlist_head *head;
1270 unsigned int hash;
1271
1272 if (!nexthop_nh->nh_dev)
1273 continue;
1274 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1275 head = &fib_info_devhash[hash];
1276 hlist_add_head(&nexthop_nh->nh_hash, head);
1277 } endfor_nexthops(fi)
1278 spin_unlock_bh(&fib_info_lock);
1279 return fi;
1280
1281 err_inval:
1282 err = -EINVAL;
1283
1284 failure:
1285 if (fi) {
1286 fi->fib_dead = 1;
1287 free_fib_info(fi);
1288 }
1289
1290 return ERR_PTR(err);
1291 }
1292
1293 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1294 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1295 struct fib_info *fi, unsigned int flags)
1296 {
1297 struct nlmsghdr *nlh;
1298 struct rtmsg *rtm;
1299
1300 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1301 if (!nlh)
1302 return -EMSGSIZE;
1303
1304 rtm = nlmsg_data(nlh);
1305 rtm->rtm_family = AF_INET;
1306 rtm->rtm_dst_len = dst_len;
1307 rtm->rtm_src_len = 0;
1308 rtm->rtm_tos = tos;
1309 if (tb_id < 256)
1310 rtm->rtm_table = tb_id;
1311 else
1312 rtm->rtm_table = RT_TABLE_COMPAT;
1313 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1314 goto nla_put_failure;
1315 rtm->rtm_type = type;
1316 rtm->rtm_flags = fi->fib_flags;
1317 rtm->rtm_scope = fi->fib_scope;
1318 rtm->rtm_protocol = fi->fib_protocol;
1319
1320 if (rtm->rtm_dst_len &&
1321 nla_put_in_addr(skb, RTA_DST, dst))
1322 goto nla_put_failure;
1323 if (fi->fib_priority &&
1324 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1325 goto nla_put_failure;
1326 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1327 goto nla_put_failure;
1328
1329 if (fi->fib_prefsrc &&
1330 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1331 goto nla_put_failure;
1332 if (fi->fib_nhs == 1) {
1333 struct in_device *in_dev;
1334
1335 if (fi->fib_nh->nh_gw &&
1336 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1337 goto nla_put_failure;
1338 if (fi->fib_nh->nh_oif &&
1339 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1340 goto nla_put_failure;
1341 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1342 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev);
1343 if (in_dev &&
1344 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1345 rtm->rtm_flags |= RTNH_F_DEAD;
1346 }
1347 #ifdef CONFIG_IP_ROUTE_CLASSID
1348 if (fi->fib_nh[0].nh_tclassid &&
1349 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1350 goto nla_put_failure;
1351 #endif
1352 if (fi->fib_nh->nh_lwtstate &&
1353 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1354 goto nla_put_failure;
1355 }
1356 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1357 if (fi->fib_nhs > 1) {
1358 struct rtnexthop *rtnh;
1359 struct nlattr *mp;
1360
1361 mp = nla_nest_start(skb, RTA_MULTIPATH);
1362 if (!mp)
1363 goto nla_put_failure;
1364
1365 for_nexthops(fi) {
1366 struct in_device *in_dev;
1367
1368 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1369 if (!rtnh)
1370 goto nla_put_failure;
1371
1372 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1373 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1374 in_dev = __in_dev_get_rtnl(nh->nh_dev);
1375 if (in_dev &&
1376 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1377 rtnh->rtnh_flags |= RTNH_F_DEAD;
1378 }
1379 rtnh->rtnh_hops = nh->nh_weight - 1;
1380 rtnh->rtnh_ifindex = nh->nh_oif;
1381
1382 if (nh->nh_gw &&
1383 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1384 goto nla_put_failure;
1385 #ifdef CONFIG_IP_ROUTE_CLASSID
1386 if (nh->nh_tclassid &&
1387 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1388 goto nla_put_failure;
1389 #endif
1390 if (nh->nh_lwtstate &&
1391 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1392 goto nla_put_failure;
1393
1394 /* length of rtnetlink header + attributes */
1395 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1396 } endfor_nexthops(fi);
1397
1398 nla_nest_end(skb, mp);
1399 }
1400 #endif
1401 nlmsg_end(skb, nlh);
1402 return 0;
1403
1404 nla_put_failure:
1405 nlmsg_cancel(skb, nlh);
1406 return -EMSGSIZE;
1407 }
1408
1409 /*
1410 * Update FIB if:
1411 * - local address disappeared -> we must delete all the entries
1412 * referring to it.
1413 * - device went down -> we must shutdown all nexthops going via it.
1414 */
1415 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1416 {
1417 int ret = 0;
1418 unsigned int hash = fib_laddr_hashfn(local);
1419 struct hlist_head *head = &fib_info_laddrhash[hash];
1420 struct net *net = dev_net(dev);
1421 int tb_id = l3mdev_fib_table(dev);
1422 struct fib_info *fi;
1423
1424 if (!fib_info_laddrhash || local == 0)
1425 return 0;
1426
1427 hlist_for_each_entry(fi, head, fib_lhash) {
1428 if (!net_eq(fi->fib_net, net) ||
1429 fi->fib_tb_id != tb_id)
1430 continue;
1431 if (fi->fib_prefsrc == local) {
1432 fi->fib_flags |= RTNH_F_DEAD;
1433 ret++;
1434 }
1435 }
1436 return ret;
1437 }
1438
1439 static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
1440 enum fib_event_type event_type)
1441 {
1442 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
1443 struct fib_nh_notifier_info info = {
1444 .fib_nh = fib_nh,
1445 };
1446
1447 switch (event_type) {
1448 case FIB_EVENT_NH_ADD:
1449 if (fib_nh->nh_flags & RTNH_F_DEAD)
1450 break;
1451 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1452 fib_nh->nh_flags & RTNH_F_LINKDOWN)
1453 break;
1454 return call_fib_notifiers(dev_net(fib_nh->nh_dev), event_type,
1455 &info.info);
1456 case FIB_EVENT_NH_DEL:
1457 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1458 fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
1459 (fib_nh->nh_flags & RTNH_F_DEAD))
1460 return call_fib_notifiers(dev_net(fib_nh->nh_dev),
1461 event_type, &info.info);
1462 default:
1463 break;
1464 }
1465
1466 return NOTIFY_DONE;
1467 }
1468
1469 /* Event force Flags Description
1470 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1471 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1472 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1473 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1474 */
1475 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1476 {
1477 int ret = 0;
1478 int scope = RT_SCOPE_NOWHERE;
1479 struct fib_info *prev_fi = NULL;
1480 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1481 struct hlist_head *head = &fib_info_devhash[hash];
1482 struct fib_nh *nh;
1483
1484 if (force)
1485 scope = -1;
1486
1487 hlist_for_each_entry(nh, head, nh_hash) {
1488 struct fib_info *fi = nh->nh_parent;
1489 int dead;
1490
1491 BUG_ON(!fi->fib_nhs);
1492 if (nh->nh_dev != dev || fi == prev_fi)
1493 continue;
1494 prev_fi = fi;
1495 dead = 0;
1496 change_nexthops(fi) {
1497 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1498 dead++;
1499 else if (nexthop_nh->nh_dev == dev &&
1500 nexthop_nh->nh_scope != scope) {
1501 switch (event) {
1502 case NETDEV_DOWN:
1503 case NETDEV_UNREGISTER:
1504 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1505 /* fall through */
1506 case NETDEV_CHANGE:
1507 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1508 break;
1509 }
1510 call_fib_nh_notifiers(nexthop_nh,
1511 FIB_EVENT_NH_DEL);
1512 dead++;
1513 }
1514 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1515 if (event == NETDEV_UNREGISTER &&
1516 nexthop_nh->nh_dev == dev) {
1517 dead = fi->fib_nhs;
1518 break;
1519 }
1520 #endif
1521 } endfor_nexthops(fi)
1522 if (dead == fi->fib_nhs) {
1523 switch (event) {
1524 case NETDEV_DOWN:
1525 case NETDEV_UNREGISTER:
1526 fi->fib_flags |= RTNH_F_DEAD;
1527 /* fall through */
1528 case NETDEV_CHANGE:
1529 fi->fib_flags |= RTNH_F_LINKDOWN;
1530 break;
1531 }
1532 ret++;
1533 }
1534
1535 fib_rebalance(fi);
1536 }
1537
1538 return ret;
1539 }
1540
1541 /* Must be invoked inside of an RCU protected region. */
1542 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1543 {
1544 struct fib_info *fi = NULL, *last_resort = NULL;
1545 struct hlist_head *fa_head = res->fa_head;
1546 struct fib_table *tb = res->table;
1547 u8 slen = 32 - res->prefixlen;
1548 int order = -1, last_idx = -1;
1549 struct fib_alias *fa, *fa1 = NULL;
1550 u32 last_prio = res->fi->fib_priority;
1551 u8 last_tos = 0;
1552
1553 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1554 struct fib_info *next_fi = fa->fa_info;
1555
1556 if (fa->fa_slen != slen)
1557 continue;
1558 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1559 continue;
1560 if (fa->tb_id != tb->tb_id)
1561 continue;
1562 if (next_fi->fib_priority > last_prio &&
1563 fa->fa_tos == last_tos) {
1564 if (last_tos)
1565 continue;
1566 break;
1567 }
1568 if (next_fi->fib_flags & RTNH_F_DEAD)
1569 continue;
1570 last_tos = fa->fa_tos;
1571 last_prio = next_fi->fib_priority;
1572
1573 if (next_fi->fib_scope != res->scope ||
1574 fa->fa_type != RTN_UNICAST)
1575 continue;
1576 if (!next_fi->fib_nh[0].nh_gw ||
1577 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1578 continue;
1579
1580 fib_alias_accessed(fa);
1581
1582 if (!fi) {
1583 if (next_fi != res->fi)
1584 break;
1585 fa1 = fa;
1586 } else if (!fib_detect_death(fi, order, &last_resort,
1587 &last_idx, fa1->fa_default)) {
1588 fib_result_assign(res, fi);
1589 fa1->fa_default = order;
1590 goto out;
1591 }
1592 fi = next_fi;
1593 order++;
1594 }
1595
1596 if (order <= 0 || !fi) {
1597 if (fa1)
1598 fa1->fa_default = -1;
1599 goto out;
1600 }
1601
1602 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1603 fa1->fa_default)) {
1604 fib_result_assign(res, fi);
1605 fa1->fa_default = order;
1606 goto out;
1607 }
1608
1609 if (last_idx >= 0)
1610 fib_result_assign(res, last_resort);
1611 fa1->fa_default = last_idx;
1612 out:
1613 return;
1614 }
1615
1616 /*
1617 * Dead device goes up. We wake up dead nexthops.
1618 * It takes sense only on multipath routes.
1619 */
1620 int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1621 {
1622 struct fib_info *prev_fi;
1623 unsigned int hash;
1624 struct hlist_head *head;
1625 struct fib_nh *nh;
1626 int ret;
1627
1628 if (!(dev->flags & IFF_UP))
1629 return 0;
1630
1631 if (nh_flags & RTNH_F_DEAD) {
1632 unsigned int flags = dev_get_flags(dev);
1633
1634 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1635 nh_flags |= RTNH_F_LINKDOWN;
1636 }
1637
1638 prev_fi = NULL;
1639 hash = fib_devindex_hashfn(dev->ifindex);
1640 head = &fib_info_devhash[hash];
1641 ret = 0;
1642
1643 hlist_for_each_entry(nh, head, nh_hash) {
1644 struct fib_info *fi = nh->nh_parent;
1645 int alive;
1646
1647 BUG_ON(!fi->fib_nhs);
1648 if (nh->nh_dev != dev || fi == prev_fi)
1649 continue;
1650
1651 prev_fi = fi;
1652 alive = 0;
1653 change_nexthops(fi) {
1654 if (!(nexthop_nh->nh_flags & nh_flags)) {
1655 alive++;
1656 continue;
1657 }
1658 if (!nexthop_nh->nh_dev ||
1659 !(nexthop_nh->nh_dev->flags & IFF_UP))
1660 continue;
1661 if (nexthop_nh->nh_dev != dev ||
1662 !__in_dev_get_rtnl(dev))
1663 continue;
1664 alive++;
1665 nexthop_nh->nh_flags &= ~nh_flags;
1666 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1667 } endfor_nexthops(fi)
1668
1669 if (alive > 0) {
1670 fi->fib_flags &= ~nh_flags;
1671 ret++;
1672 }
1673
1674 fib_rebalance(fi);
1675 }
1676
1677 return ret;
1678 }
1679
1680 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1681 static bool fib_good_nh(const struct fib_nh *nh)
1682 {
1683 int state = NUD_REACHABLE;
1684
1685 if (nh->nh_scope == RT_SCOPE_LINK) {
1686 struct neighbour *n;
1687
1688 rcu_read_lock_bh();
1689
1690 n = __ipv4_neigh_lookup_noref(nh->nh_dev,
1691 (__force u32)nh->nh_gw);
1692 if (n)
1693 state = n->nud_state;
1694
1695 rcu_read_unlock_bh();
1696 }
1697
1698 return !!(state & NUD_VALID);
1699 }
1700
1701 void fib_select_multipath(struct fib_result *res, int hash)
1702 {
1703 struct fib_info *fi = res->fi;
1704 struct net *net = fi->fib_net;
1705 bool first = false;
1706
1707 for_nexthops(fi) {
1708 if (hash > atomic_read(&nh->nh_upper_bound))
1709 continue;
1710
1711 if (!net->ipv4.sysctl_fib_multipath_use_neigh ||
1712 fib_good_nh(nh)) {
1713 res->nh_sel = nhsel;
1714 return;
1715 }
1716 if (!first) {
1717 res->nh_sel = nhsel;
1718 first = true;
1719 }
1720 } endfor_nexthops(fi);
1721 }
1722 #endif
1723
1724 void fib_select_path(struct net *net, struct fib_result *res,
1725 struct flowi4 *fl4, const struct sk_buff *skb)
1726 {
1727 bool oif_check;
1728
1729 oif_check = (fl4->flowi4_oif == 0 ||
1730 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
1731
1732 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1733 if (res->fi->fib_nhs > 1 && oif_check) {
1734 int h = fib_multipath_hash(res->fi, fl4, skb);
1735
1736 fib_select_multipath(res, h);
1737 }
1738 else
1739 #endif
1740 if (!res->prefixlen &&
1741 res->table->tb_num_default > 1 &&
1742 res->type == RTN_UNICAST && oif_check)
1743 fib_select_default(fl4, res);
1744
1745 if (!fl4->saddr)
1746 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1747 }
1748 EXPORT_SYMBOL_GPL(fib_select_path);
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