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[mirror_ubuntu-bionic-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
36 #include <net/arp.h>
37 #include <net/ip.h>
38 #include <net/protocol.h>
39 #include <net/route.h>
40 #include <net/tcp.h>
41 #include <net/sock.h>
42 #include <net/ip_fib.h>
43 #include <net/netlink.h>
44 #include <net/nexthop.h>
45 #include <net/lwtunnel.h>
46
47 #include "fib_lookup.h"
48
49 static DEFINE_SPINLOCK(fib_info_lock);
50 static struct hlist_head *fib_info_hash;
51 static struct hlist_head *fib_info_laddrhash;
52 static unsigned int fib_info_hash_size;
53 static unsigned int fib_info_cnt;
54
55 #define DEVINDEX_HASHBITS 8
56 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59 #ifdef CONFIG_IP_ROUTE_MULTIPATH
60
61 #define for_nexthops(fi) { \
62 int nhsel; const struct fib_nh *nh; \
63 for (nhsel = 0, nh = (fi)->fib_nh; \
64 nhsel < (fi)->fib_nhs; \
65 nh++, nhsel++)
66
67 #define change_nexthops(fi) { \
68 int nhsel; struct fib_nh *nexthop_nh; \
69 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
70 nhsel < (fi)->fib_nhs; \
71 nexthop_nh++, nhsel++)
72
73 #else /* CONFIG_IP_ROUTE_MULTIPATH */
74
75 /* Hope, that gcc will optimize it to get rid of dummy loop */
76
77 #define for_nexthops(fi) { \
78 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
79 for (nhsel = 0; nhsel < 1; nhsel++)
80
81 #define change_nexthops(fi) { \
82 int nhsel; \
83 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
84 for (nhsel = 0; nhsel < 1; nhsel++)
85
86 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
87
88 #define endfor_nexthops(fi) }
89
90
91 const struct fib_prop fib_props[RTN_MAX + 1] = {
92 [RTN_UNSPEC] = {
93 .error = 0,
94 .scope = RT_SCOPE_NOWHERE,
95 },
96 [RTN_UNICAST] = {
97 .error = 0,
98 .scope = RT_SCOPE_UNIVERSE,
99 },
100 [RTN_LOCAL] = {
101 .error = 0,
102 .scope = RT_SCOPE_HOST,
103 },
104 [RTN_BROADCAST] = {
105 .error = 0,
106 .scope = RT_SCOPE_LINK,
107 },
108 [RTN_ANYCAST] = {
109 .error = 0,
110 .scope = RT_SCOPE_LINK,
111 },
112 [RTN_MULTICAST] = {
113 .error = 0,
114 .scope = RT_SCOPE_UNIVERSE,
115 },
116 [RTN_BLACKHOLE] = {
117 .error = -EINVAL,
118 .scope = RT_SCOPE_UNIVERSE,
119 },
120 [RTN_UNREACHABLE] = {
121 .error = -EHOSTUNREACH,
122 .scope = RT_SCOPE_UNIVERSE,
123 },
124 [RTN_PROHIBIT] = {
125 .error = -EACCES,
126 .scope = RT_SCOPE_UNIVERSE,
127 },
128 [RTN_THROW] = {
129 .error = -EAGAIN,
130 .scope = RT_SCOPE_UNIVERSE,
131 },
132 [RTN_NAT] = {
133 .error = -EINVAL,
134 .scope = RT_SCOPE_NOWHERE,
135 },
136 [RTN_XRESOLVE] = {
137 .error = -EINVAL,
138 .scope = RT_SCOPE_NOWHERE,
139 },
140 };
141
142 static void rt_fibinfo_free(struct rtable __rcu **rtp)
143 {
144 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
145
146 if (!rt)
147 return;
148
149 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
150 * because we waited an RCU grace period before calling
151 * free_fib_info_rcu()
152 */
153
154 dst_free(&rt->dst);
155 }
156
157 static void free_nh_exceptions(struct fib_nh *nh)
158 {
159 struct fnhe_hash_bucket *hash;
160 int i;
161
162 hash = rcu_dereference_protected(nh->nh_exceptions, 1);
163 if (!hash)
164 return;
165 for (i = 0; i < FNHE_HASH_SIZE; i++) {
166 struct fib_nh_exception *fnhe;
167
168 fnhe = rcu_dereference_protected(hash[i].chain, 1);
169 while (fnhe) {
170 struct fib_nh_exception *next;
171
172 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
173
174 rt_fibinfo_free(&fnhe->fnhe_rth_input);
175 rt_fibinfo_free(&fnhe->fnhe_rth_output);
176
177 kfree(fnhe);
178
179 fnhe = next;
180 }
181 }
182 kfree(hash);
183 }
184
185 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
186 {
187 int cpu;
188
189 if (!rtp)
190 return;
191
192 for_each_possible_cpu(cpu) {
193 struct rtable *rt;
194
195 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
196 if (rt)
197 dst_free(&rt->dst);
198 }
199 free_percpu(rtp);
200 }
201
202 /* Release a nexthop info record */
203 static void free_fib_info_rcu(struct rcu_head *head)
204 {
205 struct fib_info *fi = container_of(head, struct fib_info, rcu);
206
207 change_nexthops(fi) {
208 if (nexthop_nh->nh_dev)
209 dev_put(nexthop_nh->nh_dev);
210 lwtstate_put(nexthop_nh->nh_lwtstate);
211 free_nh_exceptions(nexthop_nh);
212 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
213 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
214 } endfor_nexthops(fi);
215
216 if (fi->fib_metrics != (u32 *) dst_default_metrics)
217 kfree(fi->fib_metrics);
218 kfree(fi);
219 }
220
221 void free_fib_info(struct fib_info *fi)
222 {
223 if (fi->fib_dead == 0) {
224 pr_warn("Freeing alive fib_info %p\n", fi);
225 return;
226 }
227 fib_info_cnt--;
228 #ifdef CONFIG_IP_ROUTE_CLASSID
229 change_nexthops(fi) {
230 if (nexthop_nh->nh_tclassid)
231 fi->fib_net->ipv4.fib_num_tclassid_users--;
232 } endfor_nexthops(fi);
233 #endif
234 call_rcu(&fi->rcu, free_fib_info_rcu);
235 }
236 EXPORT_SYMBOL_GPL(free_fib_info);
237
238 void fib_release_info(struct fib_info *fi)
239 {
240 spin_lock_bh(&fib_info_lock);
241 if (fi && --fi->fib_treeref == 0) {
242 hlist_del(&fi->fib_hash);
243 if (fi->fib_prefsrc)
244 hlist_del(&fi->fib_lhash);
245 change_nexthops(fi) {
246 if (!nexthop_nh->nh_dev)
247 continue;
248 hlist_del(&nexthop_nh->nh_hash);
249 } endfor_nexthops(fi)
250 fi->fib_dead = 1;
251 fib_info_put(fi);
252 }
253 spin_unlock_bh(&fib_info_lock);
254 }
255
256 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
257 {
258 const struct fib_nh *onh = ofi->fib_nh;
259
260 for_nexthops(fi) {
261 if (nh->nh_oif != onh->nh_oif ||
262 nh->nh_gw != onh->nh_gw ||
263 nh->nh_scope != onh->nh_scope ||
264 #ifdef CONFIG_IP_ROUTE_MULTIPATH
265 nh->nh_weight != onh->nh_weight ||
266 #endif
267 #ifdef CONFIG_IP_ROUTE_CLASSID
268 nh->nh_tclassid != onh->nh_tclassid ||
269 #endif
270 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
271 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
272 return -1;
273 onh++;
274 } endfor_nexthops(fi);
275 return 0;
276 }
277
278 static inline unsigned int fib_devindex_hashfn(unsigned int val)
279 {
280 unsigned int mask = DEVINDEX_HASHSIZE - 1;
281
282 return (val ^
283 (val >> DEVINDEX_HASHBITS) ^
284 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
285 }
286
287 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
288 {
289 unsigned int mask = (fib_info_hash_size - 1);
290 unsigned int val = fi->fib_nhs;
291
292 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
293 val ^= (__force u32)fi->fib_prefsrc;
294 val ^= fi->fib_priority;
295 for_nexthops(fi) {
296 val ^= fib_devindex_hashfn(nh->nh_oif);
297 } endfor_nexthops(fi)
298
299 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
300 }
301
302 static struct fib_info *fib_find_info(const struct fib_info *nfi)
303 {
304 struct hlist_head *head;
305 struct fib_info *fi;
306 unsigned int hash;
307
308 hash = fib_info_hashfn(nfi);
309 head = &fib_info_hash[hash];
310
311 hlist_for_each_entry(fi, head, fib_hash) {
312 if (!net_eq(fi->fib_net, nfi->fib_net))
313 continue;
314 if (fi->fib_nhs != nfi->fib_nhs)
315 continue;
316 if (nfi->fib_protocol == fi->fib_protocol &&
317 nfi->fib_scope == fi->fib_scope &&
318 nfi->fib_prefsrc == fi->fib_prefsrc &&
319 nfi->fib_priority == fi->fib_priority &&
320 nfi->fib_type == fi->fib_type &&
321 memcmp(nfi->fib_metrics, fi->fib_metrics,
322 sizeof(u32) * RTAX_MAX) == 0 &&
323 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
324 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
325 return fi;
326 }
327
328 return NULL;
329 }
330
331 /* Check, that the gateway is already configured.
332 * Used only by redirect accept routine.
333 */
334 int ip_fib_check_default(__be32 gw, struct net_device *dev)
335 {
336 struct hlist_head *head;
337 struct fib_nh *nh;
338 unsigned int hash;
339
340 spin_lock(&fib_info_lock);
341
342 hash = fib_devindex_hashfn(dev->ifindex);
343 head = &fib_info_devhash[hash];
344 hlist_for_each_entry(nh, head, nh_hash) {
345 if (nh->nh_dev == dev &&
346 nh->nh_gw == gw &&
347 !(nh->nh_flags & RTNH_F_DEAD)) {
348 spin_unlock(&fib_info_lock);
349 return 0;
350 }
351 }
352
353 spin_unlock(&fib_info_lock);
354
355 return -1;
356 }
357
358 static inline size_t fib_nlmsg_size(struct fib_info *fi)
359 {
360 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
361 + nla_total_size(4) /* RTA_TABLE */
362 + nla_total_size(4) /* RTA_DST */
363 + nla_total_size(4) /* RTA_PRIORITY */
364 + nla_total_size(4) /* RTA_PREFSRC */
365 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
366
367 /* space for nested metrics */
368 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
369
370 if (fi->fib_nhs) {
371 size_t nh_encapsize = 0;
372 /* Also handles the special case fib_nhs == 1 */
373
374 /* each nexthop is packed in an attribute */
375 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
376
377 /* may contain flow and gateway attribute */
378 nhsize += 2 * nla_total_size(4);
379
380 /* grab encap info */
381 for_nexthops(fi) {
382 if (nh->nh_lwtstate) {
383 /* RTA_ENCAP_TYPE */
384 nh_encapsize += lwtunnel_get_encap_size(
385 nh->nh_lwtstate);
386 /* RTA_ENCAP */
387 nh_encapsize += nla_total_size(2);
388 }
389 } endfor_nexthops(fi);
390
391 /* all nexthops are packed in a nested attribute */
392 payload += nla_total_size((fi->fib_nhs * nhsize) +
393 nh_encapsize);
394
395 }
396
397 return payload;
398 }
399
400 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
401 int dst_len, u32 tb_id, const struct nl_info *info,
402 unsigned int nlm_flags)
403 {
404 struct sk_buff *skb;
405 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
406 int err = -ENOBUFS;
407
408 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
409 if (!skb)
410 goto errout;
411
412 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
413 fa->fa_type, key, dst_len,
414 fa->fa_tos, fa->fa_info, nlm_flags);
415 if (err < 0) {
416 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
417 WARN_ON(err == -EMSGSIZE);
418 kfree_skb(skb);
419 goto errout;
420 }
421 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
422 info->nlh, GFP_KERNEL);
423 return;
424 errout:
425 if (err < 0)
426 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
427 }
428
429 static int fib_detect_death(struct fib_info *fi, int order,
430 struct fib_info **last_resort, int *last_idx,
431 int dflt)
432 {
433 struct neighbour *n;
434 int state = NUD_NONE;
435
436 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
437 if (n) {
438 state = n->nud_state;
439 neigh_release(n);
440 } else {
441 return 0;
442 }
443 if (state == NUD_REACHABLE)
444 return 0;
445 if ((state & NUD_VALID) && order != dflt)
446 return 0;
447 if ((state & NUD_VALID) ||
448 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
449 *last_resort = fi;
450 *last_idx = order;
451 }
452 return 1;
453 }
454
455 #ifdef CONFIG_IP_ROUTE_MULTIPATH
456
457 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
458 {
459 int nhs = 0;
460
461 while (rtnh_ok(rtnh, remaining)) {
462 nhs++;
463 rtnh = rtnh_next(rtnh, &remaining);
464 }
465
466 /* leftover implies invalid nexthop configuration, discard it */
467 return remaining > 0 ? 0 : nhs;
468 }
469
470 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
471 int remaining, struct fib_config *cfg)
472 {
473 int ret;
474
475 change_nexthops(fi) {
476 int attrlen;
477
478 if (!rtnh_ok(rtnh, remaining))
479 return -EINVAL;
480
481 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
482 return -EINVAL;
483
484 nexthop_nh->nh_flags =
485 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
486 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
487 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
488
489 attrlen = rtnh_attrlen(rtnh);
490 if (attrlen > 0) {
491 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
492
493 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
494 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
495 #ifdef CONFIG_IP_ROUTE_CLASSID
496 nla = nla_find(attrs, attrlen, RTA_FLOW);
497 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
498 if (nexthop_nh->nh_tclassid)
499 fi->fib_net->ipv4.fib_num_tclassid_users++;
500 #endif
501 nla = nla_find(attrs, attrlen, RTA_ENCAP);
502 if (nla) {
503 struct lwtunnel_state *lwtstate;
504 struct nlattr *nla_entype;
505
506 nla_entype = nla_find(attrs, attrlen,
507 RTA_ENCAP_TYPE);
508 if (!nla_entype)
509 goto err_inval;
510
511 ret = lwtunnel_build_state(nla_get_u16(
512 nla_entype),
513 nla, AF_INET, cfg,
514 &lwtstate);
515 if (ret)
516 goto errout;
517 nexthop_nh->nh_lwtstate =
518 lwtstate_get(lwtstate);
519 }
520 }
521
522 rtnh = rtnh_next(rtnh, &remaining);
523 } endfor_nexthops(fi);
524
525 return 0;
526
527 err_inval:
528 ret = -EINVAL;
529
530 errout:
531 return ret;
532 }
533
534 static void fib_rebalance(struct fib_info *fi)
535 {
536 int total;
537 int w;
538 struct in_device *in_dev;
539
540 if (fi->fib_nhs < 2)
541 return;
542
543 total = 0;
544 for_nexthops(fi) {
545 if (nh->nh_flags & RTNH_F_DEAD)
546 continue;
547
548 in_dev = __in_dev_get_rtnl(nh->nh_dev);
549
550 if (in_dev &&
551 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
552 nh->nh_flags & RTNH_F_LINKDOWN)
553 continue;
554
555 total += nh->nh_weight;
556 } endfor_nexthops(fi);
557
558 w = 0;
559 change_nexthops(fi) {
560 int upper_bound;
561
562 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
563
564 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
565 upper_bound = -1;
566 } else if (in_dev &&
567 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
568 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
569 upper_bound = -1;
570 } else {
571 w += nexthop_nh->nh_weight;
572 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
573 total) - 1;
574 }
575
576 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
577 } endfor_nexthops(fi);
578 }
579
580 static inline void fib_add_weight(struct fib_info *fi,
581 const struct fib_nh *nh)
582 {
583 fi->fib_weight += nh->nh_weight;
584 }
585
586 #else /* CONFIG_IP_ROUTE_MULTIPATH */
587
588 #define fib_rebalance(fi) do { } while (0)
589 #define fib_add_weight(fi, nh) do { } while (0)
590
591 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
592
593 static int fib_encap_match(u16 encap_type,
594 struct nlattr *encap,
595 const struct fib_nh *nh,
596 const struct fib_config *cfg)
597 {
598 struct lwtunnel_state *lwtstate;
599 int ret, result = 0;
600
601 if (encap_type == LWTUNNEL_ENCAP_NONE)
602 return 0;
603
604 ret = lwtunnel_build_state(encap_type, encap,
605 AF_INET, cfg, &lwtstate);
606 if (!ret) {
607 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
608 lwtstate_free(lwtstate);
609 }
610
611 return result;
612 }
613
614 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
615 {
616 #ifdef CONFIG_IP_ROUTE_MULTIPATH
617 struct rtnexthop *rtnh;
618 int remaining;
619 #endif
620
621 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
622 return 1;
623
624 if (cfg->fc_oif || cfg->fc_gw) {
625 if (cfg->fc_encap) {
626 if (fib_encap_match(cfg->fc_encap_type,
627 cfg->fc_encap, fi->fib_nh, cfg))
628 return 1;
629 }
630 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
631 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
632 return 0;
633 return 1;
634 }
635
636 #ifdef CONFIG_IP_ROUTE_MULTIPATH
637 if (!cfg->fc_mp)
638 return 0;
639
640 rtnh = cfg->fc_mp;
641 remaining = cfg->fc_mp_len;
642
643 for_nexthops(fi) {
644 int attrlen;
645
646 if (!rtnh_ok(rtnh, remaining))
647 return -EINVAL;
648
649 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
650 return 1;
651
652 attrlen = rtnh_attrlen(rtnh);
653 if (attrlen > 0) {
654 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
655
656 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
657 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
658 return 1;
659 #ifdef CONFIG_IP_ROUTE_CLASSID
660 nla = nla_find(attrs, attrlen, RTA_FLOW);
661 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
662 return 1;
663 #endif
664 }
665
666 rtnh = rtnh_next(rtnh, &remaining);
667 } endfor_nexthops(fi);
668 #endif
669 return 0;
670 }
671
672
673 /*
674 * Picture
675 * -------
676 *
677 * Semantics of nexthop is very messy by historical reasons.
678 * We have to take into account, that:
679 * a) gateway can be actually local interface address,
680 * so that gatewayed route is direct.
681 * b) gateway must be on-link address, possibly
682 * described not by an ifaddr, but also by a direct route.
683 * c) If both gateway and interface are specified, they should not
684 * contradict.
685 * d) If we use tunnel routes, gateway could be not on-link.
686 *
687 * Attempt to reconcile all of these (alas, self-contradictory) conditions
688 * results in pretty ugly and hairy code with obscure logic.
689 *
690 * I chose to generalized it instead, so that the size
691 * of code does not increase practically, but it becomes
692 * much more general.
693 * Every prefix is assigned a "scope" value: "host" is local address,
694 * "link" is direct route,
695 * [ ... "site" ... "interior" ... ]
696 * and "universe" is true gateway route with global meaning.
697 *
698 * Every prefix refers to a set of "nexthop"s (gw, oif),
699 * where gw must have narrower scope. This recursion stops
700 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
701 * which means that gw is forced to be on link.
702 *
703 * Code is still hairy, but now it is apparently logically
704 * consistent and very flexible. F.e. as by-product it allows
705 * to co-exists in peace independent exterior and interior
706 * routing processes.
707 *
708 * Normally it looks as following.
709 *
710 * {universe prefix} -> (gw, oif) [scope link]
711 * |
712 * |-> {link prefix} -> (gw, oif) [scope local]
713 * |
714 * |-> {local prefix} (terminal node)
715 */
716 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
717 struct fib_nh *nh)
718 {
719 int err = 0;
720 struct net *net;
721 struct net_device *dev;
722
723 net = cfg->fc_nlinfo.nl_net;
724 if (nh->nh_gw) {
725 struct fib_result res;
726
727 if (nh->nh_flags & RTNH_F_ONLINK) {
728 unsigned int addr_type;
729
730 if (cfg->fc_scope >= RT_SCOPE_LINK)
731 return -EINVAL;
732 dev = __dev_get_by_index(net, nh->nh_oif);
733 if (!dev)
734 return -ENODEV;
735 if (!(dev->flags & IFF_UP))
736 return -ENETDOWN;
737 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
738 if (addr_type != RTN_UNICAST)
739 return -EINVAL;
740 if (!netif_carrier_ok(dev))
741 nh->nh_flags |= RTNH_F_LINKDOWN;
742 nh->nh_dev = dev;
743 dev_hold(dev);
744 nh->nh_scope = RT_SCOPE_LINK;
745 return 0;
746 }
747 rcu_read_lock();
748 {
749 struct fib_table *tbl = NULL;
750 struct flowi4 fl4 = {
751 .daddr = nh->nh_gw,
752 .flowi4_scope = cfg->fc_scope + 1,
753 .flowi4_oif = nh->nh_oif,
754 .flowi4_iif = LOOPBACK_IFINDEX,
755 };
756
757 /* It is not necessary, but requires a bit of thinking */
758 if (fl4.flowi4_scope < RT_SCOPE_LINK)
759 fl4.flowi4_scope = RT_SCOPE_LINK;
760
761 if (cfg->fc_table)
762 tbl = fib_get_table(net, cfg->fc_table);
763
764 if (tbl)
765 err = fib_table_lookup(tbl, &fl4, &res,
766 FIB_LOOKUP_IGNORE_LINKSTATE |
767 FIB_LOOKUP_NOREF);
768
769 /* on error or if no table given do full lookup. This
770 * is needed for example when nexthops are in the local
771 * table rather than the given table
772 */
773 if (!tbl || err) {
774 err = fib_lookup(net, &fl4, &res,
775 FIB_LOOKUP_IGNORE_LINKSTATE);
776 }
777
778 if (err) {
779 rcu_read_unlock();
780 return err;
781 }
782 }
783 err = -EINVAL;
784 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
785 goto out;
786 nh->nh_scope = res.scope;
787 nh->nh_oif = FIB_RES_OIF(res);
788 nh->nh_dev = dev = FIB_RES_DEV(res);
789 if (!dev)
790 goto out;
791 dev_hold(dev);
792 if (!netif_carrier_ok(dev))
793 nh->nh_flags |= RTNH_F_LINKDOWN;
794 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
795 } else {
796 struct in_device *in_dev;
797
798 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
799 return -EINVAL;
800
801 rcu_read_lock();
802 err = -ENODEV;
803 in_dev = inetdev_by_index(net, nh->nh_oif);
804 if (!in_dev)
805 goto out;
806 err = -ENETDOWN;
807 if (!(in_dev->dev->flags & IFF_UP))
808 goto out;
809 nh->nh_dev = in_dev->dev;
810 dev_hold(nh->nh_dev);
811 nh->nh_scope = RT_SCOPE_HOST;
812 if (!netif_carrier_ok(nh->nh_dev))
813 nh->nh_flags |= RTNH_F_LINKDOWN;
814 err = 0;
815 }
816 out:
817 rcu_read_unlock();
818 return err;
819 }
820
821 static inline unsigned int fib_laddr_hashfn(__be32 val)
822 {
823 unsigned int mask = (fib_info_hash_size - 1);
824
825 return ((__force u32)val ^
826 ((__force u32)val >> 7) ^
827 ((__force u32)val >> 14)) & mask;
828 }
829
830 static struct hlist_head *fib_info_hash_alloc(int bytes)
831 {
832 if (bytes <= PAGE_SIZE)
833 return kzalloc(bytes, GFP_KERNEL);
834 else
835 return (struct hlist_head *)
836 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
837 get_order(bytes));
838 }
839
840 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
841 {
842 if (!hash)
843 return;
844
845 if (bytes <= PAGE_SIZE)
846 kfree(hash);
847 else
848 free_pages((unsigned long) hash, get_order(bytes));
849 }
850
851 static void fib_info_hash_move(struct hlist_head *new_info_hash,
852 struct hlist_head *new_laddrhash,
853 unsigned int new_size)
854 {
855 struct hlist_head *old_info_hash, *old_laddrhash;
856 unsigned int old_size = fib_info_hash_size;
857 unsigned int i, bytes;
858
859 spin_lock_bh(&fib_info_lock);
860 old_info_hash = fib_info_hash;
861 old_laddrhash = fib_info_laddrhash;
862 fib_info_hash_size = new_size;
863
864 for (i = 0; i < old_size; i++) {
865 struct hlist_head *head = &fib_info_hash[i];
866 struct hlist_node *n;
867 struct fib_info *fi;
868
869 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
870 struct hlist_head *dest;
871 unsigned int new_hash;
872
873 new_hash = fib_info_hashfn(fi);
874 dest = &new_info_hash[new_hash];
875 hlist_add_head(&fi->fib_hash, dest);
876 }
877 }
878 fib_info_hash = new_info_hash;
879
880 for (i = 0; i < old_size; i++) {
881 struct hlist_head *lhead = &fib_info_laddrhash[i];
882 struct hlist_node *n;
883 struct fib_info *fi;
884
885 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
886 struct hlist_head *ldest;
887 unsigned int new_hash;
888
889 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
890 ldest = &new_laddrhash[new_hash];
891 hlist_add_head(&fi->fib_lhash, ldest);
892 }
893 }
894 fib_info_laddrhash = new_laddrhash;
895
896 spin_unlock_bh(&fib_info_lock);
897
898 bytes = old_size * sizeof(struct hlist_head *);
899 fib_info_hash_free(old_info_hash, bytes);
900 fib_info_hash_free(old_laddrhash, bytes);
901 }
902
903 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
904 {
905 nh->nh_saddr = inet_select_addr(nh->nh_dev,
906 nh->nh_gw,
907 nh->nh_parent->fib_scope);
908 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
909
910 return nh->nh_saddr;
911 }
912
913 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
914 {
915 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
916 fib_prefsrc != cfg->fc_dst) {
917 u32 tb_id = cfg->fc_table;
918 int rc;
919
920 if (tb_id == RT_TABLE_MAIN)
921 tb_id = RT_TABLE_LOCAL;
922
923 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
924 fib_prefsrc, tb_id);
925
926 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
927 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
928 fib_prefsrc, RT_TABLE_LOCAL);
929 }
930
931 if (rc != RTN_LOCAL)
932 return false;
933 }
934 return true;
935 }
936
937 static int
938 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
939 {
940 bool ecn_ca = false;
941 struct nlattr *nla;
942 int remaining;
943
944 if (!cfg->fc_mx)
945 return 0;
946
947 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
948 int type = nla_type(nla);
949 u32 val;
950
951 if (!type)
952 continue;
953 if (type > RTAX_MAX)
954 return -EINVAL;
955
956 if (type == RTAX_CC_ALGO) {
957 char tmp[TCP_CA_NAME_MAX];
958
959 nla_strlcpy(tmp, nla, sizeof(tmp));
960 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
961 if (val == TCP_CA_UNSPEC)
962 return -EINVAL;
963 } else {
964 val = nla_get_u32(nla);
965 }
966 if (type == RTAX_ADVMSS && val > 65535 - 40)
967 val = 65535 - 40;
968 if (type == RTAX_MTU && val > 65535 - 15)
969 val = 65535 - 15;
970 if (type == RTAX_HOPLIMIT && val > 255)
971 val = 255;
972 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
973 return -EINVAL;
974 fi->fib_metrics[type - 1] = val;
975 }
976
977 if (ecn_ca)
978 fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
979
980 return 0;
981 }
982
983 struct fib_info *fib_create_info(struct fib_config *cfg)
984 {
985 int err;
986 struct fib_info *fi = NULL;
987 struct fib_info *ofi;
988 int nhs = 1;
989 struct net *net = cfg->fc_nlinfo.nl_net;
990
991 if (cfg->fc_type > RTN_MAX)
992 goto err_inval;
993
994 /* Fast check to catch the most weird cases */
995 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
996 goto err_inval;
997
998 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
999 goto err_inval;
1000
1001 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1002 if (cfg->fc_mp) {
1003 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
1004 if (nhs == 0)
1005 goto err_inval;
1006 }
1007 #endif
1008
1009 err = -ENOBUFS;
1010 if (fib_info_cnt >= fib_info_hash_size) {
1011 unsigned int new_size = fib_info_hash_size << 1;
1012 struct hlist_head *new_info_hash;
1013 struct hlist_head *new_laddrhash;
1014 unsigned int bytes;
1015
1016 if (!new_size)
1017 new_size = 16;
1018 bytes = new_size * sizeof(struct hlist_head *);
1019 new_info_hash = fib_info_hash_alloc(bytes);
1020 new_laddrhash = fib_info_hash_alloc(bytes);
1021 if (!new_info_hash || !new_laddrhash) {
1022 fib_info_hash_free(new_info_hash, bytes);
1023 fib_info_hash_free(new_laddrhash, bytes);
1024 } else
1025 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1026
1027 if (!fib_info_hash_size)
1028 goto failure;
1029 }
1030
1031 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1032 if (!fi)
1033 goto failure;
1034 fib_info_cnt++;
1035 if (cfg->fc_mx) {
1036 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
1037 if (!fi->fib_metrics)
1038 goto failure;
1039 } else
1040 fi->fib_metrics = (u32 *) dst_default_metrics;
1041
1042 fi->fib_net = net;
1043 fi->fib_protocol = cfg->fc_protocol;
1044 fi->fib_scope = cfg->fc_scope;
1045 fi->fib_flags = cfg->fc_flags;
1046 fi->fib_priority = cfg->fc_priority;
1047 fi->fib_prefsrc = cfg->fc_prefsrc;
1048 fi->fib_type = cfg->fc_type;
1049 fi->fib_tb_id = cfg->fc_table;
1050
1051 fi->fib_nhs = nhs;
1052 change_nexthops(fi) {
1053 nexthop_nh->nh_parent = fi;
1054 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1055 if (!nexthop_nh->nh_pcpu_rth_output)
1056 goto failure;
1057 } endfor_nexthops(fi)
1058
1059 err = fib_convert_metrics(fi, cfg);
1060 if (err)
1061 goto failure;
1062
1063 if (cfg->fc_mp) {
1064 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1065 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
1066 if (err != 0)
1067 goto failure;
1068 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
1069 goto err_inval;
1070 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
1071 goto err_inval;
1072 #ifdef CONFIG_IP_ROUTE_CLASSID
1073 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
1074 goto err_inval;
1075 #endif
1076 #else
1077 goto err_inval;
1078 #endif
1079 } else {
1080 struct fib_nh *nh = fi->fib_nh;
1081
1082 if (cfg->fc_encap) {
1083 struct lwtunnel_state *lwtstate;
1084
1085 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE)
1086 goto err_inval;
1087 err = lwtunnel_build_state(cfg->fc_encap_type,
1088 cfg->fc_encap, AF_INET, cfg,
1089 &lwtstate);
1090 if (err)
1091 goto failure;
1092
1093 nh->nh_lwtstate = lwtstate_get(lwtstate);
1094 }
1095 nh->nh_oif = cfg->fc_oif;
1096 nh->nh_gw = cfg->fc_gw;
1097 nh->nh_flags = cfg->fc_flags;
1098 #ifdef CONFIG_IP_ROUTE_CLASSID
1099 nh->nh_tclassid = cfg->fc_flow;
1100 if (nh->nh_tclassid)
1101 fi->fib_net->ipv4.fib_num_tclassid_users++;
1102 #endif
1103 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1104 nh->nh_weight = 1;
1105 #endif
1106 }
1107
1108 if (fib_props[cfg->fc_type].error) {
1109 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
1110 goto err_inval;
1111 goto link_it;
1112 } else {
1113 switch (cfg->fc_type) {
1114 case RTN_UNICAST:
1115 case RTN_LOCAL:
1116 case RTN_BROADCAST:
1117 case RTN_ANYCAST:
1118 case RTN_MULTICAST:
1119 break;
1120 default:
1121 goto err_inval;
1122 }
1123 }
1124
1125 if (cfg->fc_scope > RT_SCOPE_HOST)
1126 goto err_inval;
1127
1128 if (cfg->fc_scope == RT_SCOPE_HOST) {
1129 struct fib_nh *nh = fi->fib_nh;
1130
1131 /* Local address is added. */
1132 if (nhs != 1 || nh->nh_gw)
1133 goto err_inval;
1134 nh->nh_scope = RT_SCOPE_NOWHERE;
1135 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1136 err = -ENODEV;
1137 if (!nh->nh_dev)
1138 goto failure;
1139 } else {
1140 int linkdown = 0;
1141
1142 change_nexthops(fi) {
1143 err = fib_check_nh(cfg, fi, nexthop_nh);
1144 if (err != 0)
1145 goto failure;
1146 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1147 linkdown++;
1148 } endfor_nexthops(fi)
1149 if (linkdown == fi->fib_nhs)
1150 fi->fib_flags |= RTNH_F_LINKDOWN;
1151 }
1152
1153 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc))
1154 goto err_inval;
1155
1156 change_nexthops(fi) {
1157 fib_info_update_nh_saddr(net, nexthop_nh);
1158 fib_add_weight(fi, nexthop_nh);
1159 } endfor_nexthops(fi)
1160
1161 fib_rebalance(fi);
1162
1163 link_it:
1164 ofi = fib_find_info(fi);
1165 if (ofi) {
1166 fi->fib_dead = 1;
1167 free_fib_info(fi);
1168 ofi->fib_treeref++;
1169 return ofi;
1170 }
1171
1172 fi->fib_treeref++;
1173 atomic_inc(&fi->fib_clntref);
1174 spin_lock_bh(&fib_info_lock);
1175 hlist_add_head(&fi->fib_hash,
1176 &fib_info_hash[fib_info_hashfn(fi)]);
1177 if (fi->fib_prefsrc) {
1178 struct hlist_head *head;
1179
1180 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1181 hlist_add_head(&fi->fib_lhash, head);
1182 }
1183 change_nexthops(fi) {
1184 struct hlist_head *head;
1185 unsigned int hash;
1186
1187 if (!nexthop_nh->nh_dev)
1188 continue;
1189 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1190 head = &fib_info_devhash[hash];
1191 hlist_add_head(&nexthop_nh->nh_hash, head);
1192 } endfor_nexthops(fi)
1193 spin_unlock_bh(&fib_info_lock);
1194 return fi;
1195
1196 err_inval:
1197 err = -EINVAL;
1198
1199 failure:
1200 if (fi) {
1201 fi->fib_dead = 1;
1202 free_fib_info(fi);
1203 }
1204
1205 return ERR_PTR(err);
1206 }
1207
1208 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1209 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1210 struct fib_info *fi, unsigned int flags)
1211 {
1212 struct nlmsghdr *nlh;
1213 struct rtmsg *rtm;
1214
1215 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1216 if (!nlh)
1217 return -EMSGSIZE;
1218
1219 rtm = nlmsg_data(nlh);
1220 rtm->rtm_family = AF_INET;
1221 rtm->rtm_dst_len = dst_len;
1222 rtm->rtm_src_len = 0;
1223 rtm->rtm_tos = tos;
1224 if (tb_id < 256)
1225 rtm->rtm_table = tb_id;
1226 else
1227 rtm->rtm_table = RT_TABLE_COMPAT;
1228 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1229 goto nla_put_failure;
1230 rtm->rtm_type = type;
1231 rtm->rtm_flags = fi->fib_flags;
1232 rtm->rtm_scope = fi->fib_scope;
1233 rtm->rtm_protocol = fi->fib_protocol;
1234
1235 if (rtm->rtm_dst_len &&
1236 nla_put_in_addr(skb, RTA_DST, dst))
1237 goto nla_put_failure;
1238 if (fi->fib_priority &&
1239 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1240 goto nla_put_failure;
1241 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
1242 goto nla_put_failure;
1243
1244 if (fi->fib_prefsrc &&
1245 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1246 goto nla_put_failure;
1247 if (fi->fib_nhs == 1) {
1248 struct in_device *in_dev;
1249
1250 if (fi->fib_nh->nh_gw &&
1251 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1252 goto nla_put_failure;
1253 if (fi->fib_nh->nh_oif &&
1254 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1255 goto nla_put_failure;
1256 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1257 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev);
1258 if (in_dev &&
1259 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1260 rtm->rtm_flags |= RTNH_F_DEAD;
1261 }
1262 #ifdef CONFIG_IP_ROUTE_CLASSID
1263 if (fi->fib_nh[0].nh_tclassid &&
1264 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1265 goto nla_put_failure;
1266 #endif
1267 if (fi->fib_nh->nh_lwtstate &&
1268 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1269 goto nla_put_failure;
1270 }
1271 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1272 if (fi->fib_nhs > 1) {
1273 struct rtnexthop *rtnh;
1274 struct nlattr *mp;
1275
1276 mp = nla_nest_start(skb, RTA_MULTIPATH);
1277 if (!mp)
1278 goto nla_put_failure;
1279
1280 for_nexthops(fi) {
1281 struct in_device *in_dev;
1282
1283 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1284 if (!rtnh)
1285 goto nla_put_failure;
1286
1287 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1288 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1289 in_dev = __in_dev_get_rtnl(nh->nh_dev);
1290 if (in_dev &&
1291 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1292 rtnh->rtnh_flags |= RTNH_F_DEAD;
1293 }
1294 rtnh->rtnh_hops = nh->nh_weight - 1;
1295 rtnh->rtnh_ifindex = nh->nh_oif;
1296
1297 if (nh->nh_gw &&
1298 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1299 goto nla_put_failure;
1300 #ifdef CONFIG_IP_ROUTE_CLASSID
1301 if (nh->nh_tclassid &&
1302 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1303 goto nla_put_failure;
1304 #endif
1305 if (nh->nh_lwtstate &&
1306 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1307 goto nla_put_failure;
1308
1309 /* length of rtnetlink header + attributes */
1310 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1311 } endfor_nexthops(fi);
1312
1313 nla_nest_end(skb, mp);
1314 }
1315 #endif
1316 nlmsg_end(skb, nlh);
1317 return 0;
1318
1319 nla_put_failure:
1320 nlmsg_cancel(skb, nlh);
1321 return -EMSGSIZE;
1322 }
1323
1324 /*
1325 * Update FIB if:
1326 * - local address disappeared -> we must delete all the entries
1327 * referring to it.
1328 * - device went down -> we must shutdown all nexthops going via it.
1329 */
1330 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1331 {
1332 int ret = 0;
1333 unsigned int hash = fib_laddr_hashfn(local);
1334 struct hlist_head *head = &fib_info_laddrhash[hash];
1335 struct net *net = dev_net(dev);
1336 int tb_id = l3mdev_fib_table(dev);
1337 struct fib_info *fi;
1338
1339 if (!fib_info_laddrhash || local == 0)
1340 return 0;
1341
1342 hlist_for_each_entry(fi, head, fib_lhash) {
1343 if (!net_eq(fi->fib_net, net) ||
1344 fi->fib_tb_id != tb_id)
1345 continue;
1346 if (fi->fib_prefsrc == local) {
1347 fi->fib_flags |= RTNH_F_DEAD;
1348 ret++;
1349 }
1350 }
1351 return ret;
1352 }
1353
1354 static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
1355 enum fib_event_type event_type)
1356 {
1357 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
1358 struct fib_nh_notifier_info info = {
1359 .fib_nh = fib_nh,
1360 };
1361
1362 switch (event_type) {
1363 case FIB_EVENT_NH_ADD:
1364 if (fib_nh->nh_flags & RTNH_F_DEAD)
1365 break;
1366 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1367 fib_nh->nh_flags & RTNH_F_LINKDOWN)
1368 break;
1369 return call_fib_notifiers(dev_net(fib_nh->nh_dev), event_type,
1370 &info.info);
1371 case FIB_EVENT_NH_DEL:
1372 if ((IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1373 fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
1374 (fib_nh->nh_flags & RTNH_F_DEAD))
1375 return call_fib_notifiers(dev_net(fib_nh->nh_dev),
1376 event_type, &info.info);
1377 default:
1378 break;
1379 }
1380
1381 return NOTIFY_DONE;
1382 }
1383
1384 /* Event force Flags Description
1385 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1386 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1387 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1388 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1389 */
1390 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1391 {
1392 int ret = 0;
1393 int scope = RT_SCOPE_NOWHERE;
1394 struct fib_info *prev_fi = NULL;
1395 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1396 struct hlist_head *head = &fib_info_devhash[hash];
1397 struct fib_nh *nh;
1398
1399 if (force)
1400 scope = -1;
1401
1402 hlist_for_each_entry(nh, head, nh_hash) {
1403 struct fib_info *fi = nh->nh_parent;
1404 int dead;
1405
1406 BUG_ON(!fi->fib_nhs);
1407 if (nh->nh_dev != dev || fi == prev_fi)
1408 continue;
1409 prev_fi = fi;
1410 dead = 0;
1411 change_nexthops(fi) {
1412 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1413 dead++;
1414 else if (nexthop_nh->nh_dev == dev &&
1415 nexthop_nh->nh_scope != scope) {
1416 switch (event) {
1417 case NETDEV_DOWN:
1418 case NETDEV_UNREGISTER:
1419 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1420 /* fall through */
1421 case NETDEV_CHANGE:
1422 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1423 break;
1424 }
1425 call_fib_nh_notifiers(nexthop_nh,
1426 FIB_EVENT_NH_DEL);
1427 dead++;
1428 }
1429 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1430 if (event == NETDEV_UNREGISTER &&
1431 nexthop_nh->nh_dev == dev) {
1432 dead = fi->fib_nhs;
1433 break;
1434 }
1435 #endif
1436 } endfor_nexthops(fi)
1437 if (dead == fi->fib_nhs) {
1438 switch (event) {
1439 case NETDEV_DOWN:
1440 case NETDEV_UNREGISTER:
1441 fi->fib_flags |= RTNH_F_DEAD;
1442 /* fall through */
1443 case NETDEV_CHANGE:
1444 fi->fib_flags |= RTNH_F_LINKDOWN;
1445 break;
1446 }
1447 ret++;
1448 }
1449
1450 fib_rebalance(fi);
1451 }
1452
1453 return ret;
1454 }
1455
1456 /* Must be invoked inside of an RCU protected region. */
1457 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1458 {
1459 struct fib_info *fi = NULL, *last_resort = NULL;
1460 struct hlist_head *fa_head = res->fa_head;
1461 struct fib_table *tb = res->table;
1462 u8 slen = 32 - res->prefixlen;
1463 int order = -1, last_idx = -1;
1464 struct fib_alias *fa, *fa1 = NULL;
1465 u32 last_prio = res->fi->fib_priority;
1466 u8 last_tos = 0;
1467
1468 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1469 struct fib_info *next_fi = fa->fa_info;
1470
1471 if (fa->fa_slen != slen)
1472 continue;
1473 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1474 continue;
1475 if (fa->tb_id != tb->tb_id)
1476 continue;
1477 if (next_fi->fib_priority > last_prio &&
1478 fa->fa_tos == last_tos) {
1479 if (last_tos)
1480 continue;
1481 break;
1482 }
1483 if (next_fi->fib_flags & RTNH_F_DEAD)
1484 continue;
1485 last_tos = fa->fa_tos;
1486 last_prio = next_fi->fib_priority;
1487
1488 if (next_fi->fib_scope != res->scope ||
1489 fa->fa_type != RTN_UNICAST)
1490 continue;
1491 if (!next_fi->fib_nh[0].nh_gw ||
1492 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1493 continue;
1494
1495 fib_alias_accessed(fa);
1496
1497 if (!fi) {
1498 if (next_fi != res->fi)
1499 break;
1500 fa1 = fa;
1501 } else if (!fib_detect_death(fi, order, &last_resort,
1502 &last_idx, fa1->fa_default)) {
1503 fib_result_assign(res, fi);
1504 fa1->fa_default = order;
1505 goto out;
1506 }
1507 fi = next_fi;
1508 order++;
1509 }
1510
1511 if (order <= 0 || !fi) {
1512 if (fa1)
1513 fa1->fa_default = -1;
1514 goto out;
1515 }
1516
1517 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1518 fa1->fa_default)) {
1519 fib_result_assign(res, fi);
1520 fa1->fa_default = order;
1521 goto out;
1522 }
1523
1524 if (last_idx >= 0)
1525 fib_result_assign(res, last_resort);
1526 fa1->fa_default = last_idx;
1527 out:
1528 return;
1529 }
1530
1531 /*
1532 * Dead device goes up. We wake up dead nexthops.
1533 * It takes sense only on multipath routes.
1534 */
1535 int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1536 {
1537 struct fib_info *prev_fi;
1538 unsigned int hash;
1539 struct hlist_head *head;
1540 struct fib_nh *nh;
1541 int ret;
1542
1543 if (!(dev->flags & IFF_UP))
1544 return 0;
1545
1546 if (nh_flags & RTNH_F_DEAD) {
1547 unsigned int flags = dev_get_flags(dev);
1548
1549 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1550 nh_flags |= RTNH_F_LINKDOWN;
1551 }
1552
1553 prev_fi = NULL;
1554 hash = fib_devindex_hashfn(dev->ifindex);
1555 head = &fib_info_devhash[hash];
1556 ret = 0;
1557
1558 hlist_for_each_entry(nh, head, nh_hash) {
1559 struct fib_info *fi = nh->nh_parent;
1560 int alive;
1561
1562 BUG_ON(!fi->fib_nhs);
1563 if (nh->nh_dev != dev || fi == prev_fi)
1564 continue;
1565
1566 prev_fi = fi;
1567 alive = 0;
1568 change_nexthops(fi) {
1569 if (!(nexthop_nh->nh_flags & nh_flags)) {
1570 alive++;
1571 continue;
1572 }
1573 if (!nexthop_nh->nh_dev ||
1574 !(nexthop_nh->nh_dev->flags & IFF_UP))
1575 continue;
1576 if (nexthop_nh->nh_dev != dev ||
1577 !__in_dev_get_rtnl(dev))
1578 continue;
1579 alive++;
1580 nexthop_nh->nh_flags &= ~nh_flags;
1581 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1582 } endfor_nexthops(fi)
1583
1584 if (alive > 0) {
1585 fi->fib_flags &= ~nh_flags;
1586 ret++;
1587 }
1588
1589 fib_rebalance(fi);
1590 }
1591
1592 return ret;
1593 }
1594
1595 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1596 static bool fib_good_nh(const struct fib_nh *nh)
1597 {
1598 int state = NUD_REACHABLE;
1599
1600 if (nh->nh_scope == RT_SCOPE_LINK) {
1601 struct neighbour *n;
1602
1603 rcu_read_lock_bh();
1604
1605 n = __ipv4_neigh_lookup_noref(nh->nh_dev,
1606 (__force u32)nh->nh_gw);
1607 if (n)
1608 state = n->nud_state;
1609
1610 rcu_read_unlock_bh();
1611 }
1612
1613 return !!(state & NUD_VALID);
1614 }
1615
1616 void fib_select_multipath(struct fib_result *res, int hash)
1617 {
1618 struct fib_info *fi = res->fi;
1619 struct net *net = fi->fib_net;
1620 bool first = false;
1621
1622 for_nexthops(fi) {
1623 if (hash > atomic_read(&nh->nh_upper_bound))
1624 continue;
1625
1626 if (!net->ipv4.sysctl_fib_multipath_use_neigh ||
1627 fib_good_nh(nh)) {
1628 res->nh_sel = nhsel;
1629 return;
1630 }
1631 if (!first) {
1632 res->nh_sel = nhsel;
1633 first = true;
1634 }
1635 } endfor_nexthops(fi);
1636 }
1637 #endif
1638
1639 void fib_select_path(struct net *net, struct fib_result *res,
1640 struct flowi4 *fl4, const struct sk_buff *skb)
1641 {
1642 bool oif_check;
1643
1644 oif_check = (fl4->flowi4_oif == 0 ||
1645 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
1646
1647 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1648 if (res->fi->fib_nhs > 1 && oif_check) {
1649 int h = fib_multipath_hash(res->fi, fl4, skb);
1650
1651 fib_select_multipath(res, h);
1652 }
1653 else
1654 #endif
1655 if (!res->prefixlen &&
1656 res->table->tb_num_default > 1 &&
1657 res->type == RTN_UNICAST && oif_check)
1658 fib_select_default(fl4, res);
1659
1660 if (!fl4->saddr)
1661 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1662 }
1663 EXPORT_SYMBOL_GPL(fib_select_path);
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