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ARM: dma-api: fix max_pfn off-by-one error in __dma_supported()
[linux/fpc-iii.git] / net / ipv4 / fib_semantics.c
bloba803cdd9400a63f7f212ef7735a0490552d49497
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: semantics.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/uaccess.h>
13 #include <linux/bitops.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/jiffies.h>
17 #include <linux/mm.h>
18 #include <linux/string.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/errno.h>
22 #include <linux/in.h>
23 #include <linux/inet.h>
24 #include <linux/inetdevice.h>
25 #include <linux/netdevice.h>
26 #include <linux/if_arp.h>
27 #include <linux/proc_fs.h>
28 #include <linux/skbuff.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/netlink.h>
32
33 #include <net/arp.h>
34 #include <net/ip.h>
35 #include <net/protocol.h>
36 #include <net/route.h>
37 #include <net/tcp.h>
38 #include <net/sock.h>
39 #include <net/ip_fib.h>
40 #include <net/ip6_fib.h>
41 #include <net/nexthop.h>
42 #include <net/netlink.h>
43 #include <net/rtnh.h>
44 #include <net/lwtunnel.h>
45 #include <net/fib_notifier.h>
46 #include <net/addrconf.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 /* for_nexthops and change_nexthops only used when nexthop object
61 * is not set in a fib_info. The logic within can reference fib_nh.
62 */
63 #ifdef CONFIG_IP_ROUTE_MULTIPATH
64
65 #define for_nexthops(fi) { \
66 int nhsel; const struct fib_nh *nh; \
67 for (nhsel = 0, nh = (fi)->fib_nh; \
68 nhsel < fib_info_num_path((fi)); \
69 nh++, nhsel++)
70
71 #define change_nexthops(fi) { \
72 int nhsel; struct fib_nh *nexthop_nh; \
73 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
74 nhsel < fib_info_num_path((fi)); \
75 nexthop_nh++, nhsel++)
76
77 #else /* CONFIG_IP_ROUTE_MULTIPATH */
78
79 /* Hope, that gcc will optimize it to get rid of dummy loop */
80
81 #define for_nexthops(fi) { \
82 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
83 for (nhsel = 0; nhsel < 1; nhsel++)
84
85 #define change_nexthops(fi) { \
86 int nhsel; \
87 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
88 for (nhsel = 0; nhsel < 1; nhsel++)
89
90 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
91
92 #define endfor_nexthops(fi) }
93
94
95 const struct fib_prop fib_props[RTN_MAX + 1] = {
96 [RTN_UNSPEC] = {
97 .error = 0,
98 .scope = RT_SCOPE_NOWHERE,
99 },
100 [RTN_UNICAST] = {
101 .error = 0,
102 .scope = RT_SCOPE_UNIVERSE,
103 },
104 [RTN_LOCAL] = {
105 .error = 0,
106 .scope = RT_SCOPE_HOST,
107 },
108 [RTN_BROADCAST] = {
109 .error = 0,
110 .scope = RT_SCOPE_LINK,
111 },
112 [RTN_ANYCAST] = {
113 .error = 0,
114 .scope = RT_SCOPE_LINK,
115 },
116 [RTN_MULTICAST] = {
117 .error = 0,
118 .scope = RT_SCOPE_UNIVERSE,
119 },
120 [RTN_BLACKHOLE] = {
121 .error = -EINVAL,
122 .scope = RT_SCOPE_UNIVERSE,
123 },
124 [RTN_UNREACHABLE] = {
125 .error = -EHOSTUNREACH,
126 .scope = RT_SCOPE_UNIVERSE,
127 },
128 [RTN_PROHIBIT] = {
129 .error = -EACCES,
130 .scope = RT_SCOPE_UNIVERSE,
131 },
132 [RTN_THROW] = {
133 .error = -EAGAIN,
134 .scope = RT_SCOPE_UNIVERSE,
135 },
136 [RTN_NAT] = {
137 .error = -EINVAL,
138 .scope = RT_SCOPE_NOWHERE,
139 },
140 [RTN_XRESOLVE] = {
141 .error = -EINVAL,
142 .scope = RT_SCOPE_NOWHERE,
143 },
144 };
145
146 static void rt_fibinfo_free(struct rtable __rcu **rtp)
147 {
148 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
149
150 if (!rt)
151 return;
152
153 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
154 * because we waited an RCU grace period before calling
155 * free_fib_info_rcu()
156 */
157
158 dst_dev_put(&rt->dst);
159 dst_release_immediate(&rt->dst);
160 }
161
162 static void free_nh_exceptions(struct fib_nh_common *nhc)
163 {
164 struct fnhe_hash_bucket *hash;
165 int i;
166
167 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
168 if (!hash)
169 return;
170 for (i = 0; i < FNHE_HASH_SIZE; i++) {
171 struct fib_nh_exception *fnhe;
172
173 fnhe = rcu_dereference_protected(hash[i].chain, 1);
174 while (fnhe) {
175 struct fib_nh_exception *next;
176
177 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
178
179 rt_fibinfo_free(&fnhe->fnhe_rth_input);
180 rt_fibinfo_free(&fnhe->fnhe_rth_output);
181
182 kfree(fnhe);
183
184 fnhe = next;
185 }
186 }
187 kfree(hash);
188 }
189
190 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
191 {
192 int cpu;
193
194 if (!rtp)
195 return;
196
197 for_each_possible_cpu(cpu) {
198 struct rtable *rt;
199
200 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
201 if (rt) {
202 dst_dev_put(&rt->dst);
203 dst_release_immediate(&rt->dst);
204 }
205 }
206 free_percpu(rtp);
207 }
208
209 void fib_nh_common_release(struct fib_nh_common *nhc)
210 {
211 if (nhc->nhc_dev)
212 dev_put(nhc->nhc_dev);
213
214 lwtstate_put(nhc->nhc_lwtstate);
215 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
216 rt_fibinfo_free(&nhc->nhc_rth_input);
217 free_nh_exceptions(nhc);
218 }
219 EXPORT_SYMBOL_GPL(fib_nh_common_release);
220
221 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
222 {
223 #ifdef CONFIG_IP_ROUTE_CLASSID
224 if (fib_nh->nh_tclassid)
225 net->ipv4.fib_num_tclassid_users--;
226 #endif
227 fib_nh_common_release(&fib_nh->nh_common);
228 }
229
230 /* Release a nexthop info record */
231 static void free_fib_info_rcu(struct rcu_head *head)
232 {
233 struct fib_info *fi = container_of(head, struct fib_info, rcu);
234
235 if (fi->nh) {
236 nexthop_put(fi->nh);
237 } else {
238 change_nexthops(fi) {
239 fib_nh_release(fi->fib_net, nexthop_nh);
240 } endfor_nexthops(fi);
241 }
242
243 ip_fib_metrics_put(fi->fib_metrics);
244
245 kfree(fi);
246 }
247
248 void free_fib_info(struct fib_info *fi)
249 {
250 if (fi->fib_dead == 0) {
251 pr_warn("Freeing alive fib_info %p\n", fi);
252 return;
253 }
254 fib_info_cnt--;
255
256 call_rcu(&fi->rcu, free_fib_info_rcu);
257 }
258 EXPORT_SYMBOL_GPL(free_fib_info);
259
260 void fib_release_info(struct fib_info *fi)
261 {
262 spin_lock_bh(&fib_info_lock);
263 if (fi && --fi->fib_treeref == 0) {
264 hlist_del(&fi->fib_hash);
265 if (fi->fib_prefsrc)
266 hlist_del(&fi->fib_lhash);
267 if (fi->nh) {
268 list_del(&fi->nh_list);
269 } else {
270 change_nexthops(fi) {
271 if (!nexthop_nh->fib_nh_dev)
272 continue;
273 hlist_del(&nexthop_nh->nh_hash);
274 } endfor_nexthops(fi)
275 }
276 fi->fib_dead = 1;
277 fib_info_put(fi);
278 }
279 spin_unlock_bh(&fib_info_lock);
280 }
281
282 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
283 {
284 const struct fib_nh *onh;
285
286 if (fi->nh || ofi->nh)
287 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
288
289 if (ofi->fib_nhs == 0)
290 return 0;
291
292 for_nexthops(fi) {
293 onh = fib_info_nh(ofi, nhsel);
294
295 if (nh->fib_nh_oif != onh->fib_nh_oif ||
296 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
297 nh->fib_nh_scope != onh->fib_nh_scope ||
298 #ifdef CONFIG_IP_ROUTE_MULTIPATH
299 nh->fib_nh_weight != onh->fib_nh_weight ||
300 #endif
301 #ifdef CONFIG_IP_ROUTE_CLASSID
302 nh->nh_tclassid != onh->nh_tclassid ||
303 #endif
304 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
305 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
306 return -1;
307
308 if (nh->fib_nh_gw_family == AF_INET &&
309 nh->fib_nh_gw4 != onh->fib_nh_gw4)
310 return -1;
311
312 if (nh->fib_nh_gw_family == AF_INET6 &&
313 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
314 return -1;
315 } endfor_nexthops(fi);
316 return 0;
317 }
318
319 static inline unsigned int fib_devindex_hashfn(unsigned int val)
320 {
321 unsigned int mask = DEVINDEX_HASHSIZE - 1;
322
323 return (val ^
324 (val >> DEVINDEX_HASHBITS) ^
325 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
326 }
327
328 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
329 u32 prefsrc, u32 priority)
330 {
331 unsigned int val = init_val;
332
333 val ^= (protocol << 8) | scope;
334 val ^= prefsrc;
335 val ^= priority;
336
337 return val;
338 }
339
340 static unsigned int fib_info_hashfn_result(unsigned int val)
341 {
342 unsigned int mask = (fib_info_hash_size - 1);
343
344 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
345 }
346
347 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
348 {
349 unsigned int val;
350
351 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
352 fi->fib_scope, (__force u32)fi->fib_prefsrc,
353 fi->fib_priority);
354
355 if (fi->nh) {
356 val ^= fib_devindex_hashfn(fi->nh->id);
357 } else {
358 for_nexthops(fi) {
359 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
360 } endfor_nexthops(fi)
361 }
362
363 return fib_info_hashfn_result(val);
364 }
365
366 /* no metrics, only nexthop id */
367 static struct fib_info *fib_find_info_nh(struct net *net,
368 const struct fib_config *cfg)
369 {
370 struct hlist_head *head;
371 struct fib_info *fi;
372 unsigned int hash;
373
374 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
375 cfg->fc_protocol, cfg->fc_scope,
376 (__force u32)cfg->fc_prefsrc,
377 cfg->fc_priority);
378 hash = fib_info_hashfn_result(hash);
379 head = &fib_info_hash[hash];
380
381 hlist_for_each_entry(fi, head, fib_hash) {
382 if (!net_eq(fi->fib_net, net))
383 continue;
384 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
385 continue;
386 if (cfg->fc_protocol == fi->fib_protocol &&
387 cfg->fc_scope == fi->fib_scope &&
388 cfg->fc_prefsrc == fi->fib_prefsrc &&
389 cfg->fc_priority == fi->fib_priority &&
390 cfg->fc_type == fi->fib_type &&
391 cfg->fc_table == fi->fib_tb_id &&
392 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
393 return fi;
394 }
395
396 return NULL;
397 }
398
399 static struct fib_info *fib_find_info(struct fib_info *nfi)
400 {
401 struct hlist_head *head;
402 struct fib_info *fi;
403 unsigned int hash;
404
405 hash = fib_info_hashfn(nfi);
406 head = &fib_info_hash[hash];
407
408 hlist_for_each_entry(fi, head, fib_hash) {
409 if (!net_eq(fi->fib_net, nfi->fib_net))
410 continue;
411 if (fi->fib_nhs != nfi->fib_nhs)
412 continue;
413 if (nfi->fib_protocol == fi->fib_protocol &&
414 nfi->fib_scope == fi->fib_scope &&
415 nfi->fib_prefsrc == fi->fib_prefsrc &&
416 nfi->fib_priority == fi->fib_priority &&
417 nfi->fib_type == fi->fib_type &&
418 memcmp(nfi->fib_metrics, fi->fib_metrics,
419 sizeof(u32) * RTAX_MAX) == 0 &&
420 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
421 nh_comp(fi, nfi) == 0)
422 return fi;
423 }
424
425 return NULL;
426 }
427
428 /* Check, that the gateway is already configured.
429 * Used only by redirect accept routine.
430 */
431 int ip_fib_check_default(__be32 gw, struct net_device *dev)
432 {
433 struct hlist_head *head;
434 struct fib_nh *nh;
435 unsigned int hash;
436
437 spin_lock(&fib_info_lock);
438
439 hash = fib_devindex_hashfn(dev->ifindex);
440 head = &fib_info_devhash[hash];
441 hlist_for_each_entry(nh, head, nh_hash) {
442 if (nh->fib_nh_dev == dev &&
443 nh->fib_nh_gw4 == gw &&
444 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
445 spin_unlock(&fib_info_lock);
446 return 0;
447 }
448 }
449
450 spin_unlock(&fib_info_lock);
451
452 return -1;
453 }
454
455 static inline size_t fib_nlmsg_size(struct fib_info *fi)
456 {
457 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
458 + nla_total_size(4) /* RTA_TABLE */
459 + nla_total_size(4) /* RTA_DST */
460 + nla_total_size(4) /* RTA_PRIORITY */
461 + nla_total_size(4) /* RTA_PREFSRC */
462 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
463 unsigned int nhs = fib_info_num_path(fi);
464
465 /* space for nested metrics */
466 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
467
468 if (fi->nh)
469 payload += nla_total_size(4); /* RTA_NH_ID */
470
471 if (nhs) {
472 size_t nh_encapsize = 0;
473 /* Also handles the special case nhs == 1 */
474
475 /* each nexthop is packed in an attribute */
476 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
477 unsigned int i;
478
479 /* may contain flow and gateway attribute */
480 nhsize += 2 * nla_total_size(4);
481
482 /* grab encap info */
483 for (i = 0; i < fib_info_num_path(fi); i++) {
484 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
485
486 if (nhc->nhc_lwtstate) {
487 /* RTA_ENCAP_TYPE */
488 nh_encapsize += lwtunnel_get_encap_size(
489 nhc->nhc_lwtstate);
490 /* RTA_ENCAP */
491 nh_encapsize += nla_total_size(2);
492 }
493 }
494
495 /* all nexthops are packed in a nested attribute */
496 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
497
498 }
499
500 return payload;
501 }
502
503 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
504 int dst_len, u32 tb_id, const struct nl_info *info,
505 unsigned int nlm_flags)
506 {
507 struct fib_rt_info fri;
508 struct sk_buff *skb;
509 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
510 int err = -ENOBUFS;
511
512 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
513 if (!skb)
514 goto errout;
515
516 fri.fi = fa->fa_info;
517 fri.tb_id = tb_id;
518 fri.dst = key;
519 fri.dst_len = dst_len;
520 fri.tos = fa->fa_tos;
521 fri.type = fa->fa_type;
522 fri.offload = fa->offload;
523 fri.trap = fa->trap;
524 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
525 if (err < 0) {
526 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
527 WARN_ON(err == -EMSGSIZE);
528 kfree_skb(skb);
529 goto errout;
530 }
531 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
532 info->nlh, GFP_KERNEL);
533 return;
534 errout:
535 if (err < 0)
536 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
537 }
538
539 static int fib_detect_death(struct fib_info *fi, int order,
540 struct fib_info **last_resort, int *last_idx,
541 int dflt)
542 {
543 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
544 struct neighbour *n;
545 int state = NUD_NONE;
546
547 if (likely(nhc->nhc_gw_family == AF_INET))
548 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
549 else if (nhc->nhc_gw_family == AF_INET6)
550 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
551 nhc->nhc_dev);
552 else
553 n = NULL;
554
555 if (n) {
556 state = n->nud_state;
557 neigh_release(n);
558 } else {
559 return 0;
560 }
561 if (state == NUD_REACHABLE)
562 return 0;
563 if ((state & NUD_VALID) && order != dflt)
564 return 0;
565 if ((state & NUD_VALID) ||
566 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
567 *last_resort = fi;
568 *last_idx = order;
569 }
570 return 1;
571 }
572
573 int fib_nh_common_init(struct fib_nh_common *nhc, struct nlattr *encap,
574 u16 encap_type, void *cfg, gfp_t gfp_flags,
575 struct netlink_ext_ack *extack)
576 {
577 int err;
578
579 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
580 gfp_flags);
581 if (!nhc->nhc_pcpu_rth_output)
582 return -ENOMEM;
583
584 if (encap) {
585 struct lwtunnel_state *lwtstate;
586
587 if (encap_type == LWTUNNEL_ENCAP_NONE) {
588 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
589 err = -EINVAL;
590 goto lwt_failure;
591 }
592 err = lwtunnel_build_state(encap_type, encap, nhc->nhc_family,
593 cfg, &lwtstate, extack);
594 if (err)
595 goto lwt_failure;
596
597 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
598 }
599
600 return 0;
601
602 lwt_failure:
603 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
604 nhc->nhc_pcpu_rth_output = NULL;
605 return err;
606 }
607 EXPORT_SYMBOL_GPL(fib_nh_common_init);
608
609 int fib_nh_init(struct net *net, struct fib_nh *nh,
610 struct fib_config *cfg, int nh_weight,
611 struct netlink_ext_ack *extack)
612 {
613 int err;
614
615 nh->fib_nh_family = AF_INET;
616
617 err = fib_nh_common_init(&nh->nh_common, cfg->fc_encap,
618 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
619 if (err)
620 return err;
621
622 nh->fib_nh_oif = cfg->fc_oif;
623 nh->fib_nh_gw_family = cfg->fc_gw_family;
624 if (cfg->fc_gw_family == AF_INET)
625 nh->fib_nh_gw4 = cfg->fc_gw4;
626 else if (cfg->fc_gw_family == AF_INET6)
627 nh->fib_nh_gw6 = cfg->fc_gw6;
628
629 nh->fib_nh_flags = cfg->fc_flags;
630
631 #ifdef CONFIG_IP_ROUTE_CLASSID
632 nh->nh_tclassid = cfg->fc_flow;
633 if (nh->nh_tclassid)
634 net->ipv4.fib_num_tclassid_users++;
635 #endif
636 #ifdef CONFIG_IP_ROUTE_MULTIPATH
637 nh->fib_nh_weight = nh_weight;
638 #endif
639 return 0;
640 }
641
642 #ifdef CONFIG_IP_ROUTE_MULTIPATH
643
644 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
645 struct netlink_ext_ack *extack)
646 {
647 int nhs = 0;
648
649 while (rtnh_ok(rtnh, remaining)) {
650 nhs++;
651 rtnh = rtnh_next(rtnh, &remaining);
652 }
653
654 /* leftover implies invalid nexthop configuration, discard it */
655 if (remaining > 0) {
656 NL_SET_ERR_MSG(extack,
657 "Invalid nexthop configuration - extra data after nexthops");
658 nhs = 0;
659 }
660
661 return nhs;
662 }
663
664 /* only called when fib_nh is integrated into fib_info */
665 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
666 int remaining, struct fib_config *cfg,
667 struct netlink_ext_ack *extack)
668 {
669 struct net *net = fi->fib_net;
670 struct fib_config fib_cfg;
671 struct fib_nh *nh;
672 int ret;
673
674 change_nexthops(fi) {
675 int attrlen;
676
677 memset(&fib_cfg, 0, sizeof(fib_cfg));
678
679 if (!rtnh_ok(rtnh, remaining)) {
680 NL_SET_ERR_MSG(extack,
681 "Invalid nexthop configuration - extra data after nexthop");
682 return -EINVAL;
683 }
684
685 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
686 NL_SET_ERR_MSG(extack,
687 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
688 return -EINVAL;
689 }
690
691 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
692 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
693
694 attrlen = rtnh_attrlen(rtnh);
695 if (attrlen > 0) {
696 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
697
698 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
699 nlav = nla_find(attrs, attrlen, RTA_VIA);
700 if (nla && nlav) {
701 NL_SET_ERR_MSG(extack,
702 "Nexthop configuration can not contain both GATEWAY and VIA");
703 return -EINVAL;
704 }
705 if (nla) {
706 fib_cfg.fc_gw4 = nla_get_in_addr(nla);
707 if (fib_cfg.fc_gw4)
708 fib_cfg.fc_gw_family = AF_INET;
709 } else if (nlav) {
710 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
711 if (ret)
712 goto errout;
713 }
714
715 nla = nla_find(attrs, attrlen, RTA_FLOW);
716 if (nla)
717 fib_cfg.fc_flow = nla_get_u32(nla);
718
719 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
720 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
721 if (nla)
722 fib_cfg.fc_encap_type = nla_get_u16(nla);
723 }
724
725 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
726 rtnh->rtnh_hops + 1, extack);
727 if (ret)
728 goto errout;
729
730 rtnh = rtnh_next(rtnh, &remaining);
731 } endfor_nexthops(fi);
732
733 ret = -EINVAL;
734 nh = fib_info_nh(fi, 0);
735 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
736 NL_SET_ERR_MSG(extack,
737 "Nexthop device index does not match RTA_OIF");
738 goto errout;
739 }
740 if (cfg->fc_gw_family) {
741 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
742 (cfg->fc_gw_family == AF_INET &&
743 nh->fib_nh_gw4 != cfg->fc_gw4) ||
744 (cfg->fc_gw_family == AF_INET6 &&
745 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
746 NL_SET_ERR_MSG(extack,
747 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
748 goto errout;
749 }
750 }
751 #ifdef CONFIG_IP_ROUTE_CLASSID
752 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
753 NL_SET_ERR_MSG(extack,
754 "Nexthop class id does not match RTA_FLOW");
755 goto errout;
756 }
757 #endif
758 ret = 0;
759 errout:
760 return ret;
761 }
762
763 /* only called when fib_nh is integrated into fib_info */
764 static void fib_rebalance(struct fib_info *fi)
765 {
766 int total;
767 int w;
768
769 if (fib_info_num_path(fi) < 2)
770 return;
771
772 total = 0;
773 for_nexthops(fi) {
774 if (nh->fib_nh_flags & RTNH_F_DEAD)
775 continue;
776
777 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
778 nh->fib_nh_flags & RTNH_F_LINKDOWN)
779 continue;
780
781 total += nh->fib_nh_weight;
782 } endfor_nexthops(fi);
783
784 w = 0;
785 change_nexthops(fi) {
786 int upper_bound;
787
788 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
789 upper_bound = -1;
790 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
791 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
792 upper_bound = -1;
793 } else {
794 w += nexthop_nh->fib_nh_weight;
795 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
796 total) - 1;
797 }
798
799 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
800 } endfor_nexthops(fi);
801 }
802 #else /* CONFIG_IP_ROUTE_MULTIPATH */
803
804 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
805 int remaining, struct fib_config *cfg,
806 struct netlink_ext_ack *extack)
807 {
808 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
809
810 return -EINVAL;
811 }
812
813 #define fib_rebalance(fi) do { } while (0)
814
815 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
816
817 static int fib_encap_match(u16 encap_type,
818 struct nlattr *encap,
819 const struct fib_nh *nh,
820 const struct fib_config *cfg,
821 struct netlink_ext_ack *extack)
822 {
823 struct lwtunnel_state *lwtstate;
824 int ret, result = 0;
825
826 if (encap_type == LWTUNNEL_ENCAP_NONE)
827 return 0;
828
829 ret = lwtunnel_build_state(encap_type, encap, AF_INET,
830 cfg, &lwtstate, extack);
831 if (!ret) {
832 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
833 lwtstate_free(lwtstate);
834 }
835
836 return result;
837 }
838
839 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
840 struct netlink_ext_ack *extack)
841 {
842 #ifdef CONFIG_IP_ROUTE_MULTIPATH
843 struct rtnexthop *rtnh;
844 int remaining;
845 #endif
846
847 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
848 return 1;
849
850 if (cfg->fc_nh_id) {
851 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
852 return 0;
853 return 1;
854 }
855
856 if (cfg->fc_oif || cfg->fc_gw_family) {
857 struct fib_nh *nh = fib_info_nh(fi, 0);
858
859 if (cfg->fc_encap) {
860 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
861 nh, cfg, extack))
862 return 1;
863 }
864 #ifdef CONFIG_IP_ROUTE_CLASSID
865 if (cfg->fc_flow &&
866 cfg->fc_flow != nh->nh_tclassid)
867 return 1;
868 #endif
869 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
870 (cfg->fc_gw_family &&
871 cfg->fc_gw_family != nh->fib_nh_gw_family))
872 return 1;
873
874 if (cfg->fc_gw_family == AF_INET &&
875 cfg->fc_gw4 != nh->fib_nh_gw4)
876 return 1;
877
878 if (cfg->fc_gw_family == AF_INET6 &&
879 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
880 return 1;
881
882 return 0;
883 }
884
885 #ifdef CONFIG_IP_ROUTE_MULTIPATH
886 if (!cfg->fc_mp)
887 return 0;
888
889 rtnh = cfg->fc_mp;
890 remaining = cfg->fc_mp_len;
891
892 for_nexthops(fi) {
893 int attrlen;
894
895 if (!rtnh_ok(rtnh, remaining))
896 return -EINVAL;
897
898 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
899 return 1;
900
901 attrlen = rtnh_attrlen(rtnh);
902 if (attrlen > 0) {
903 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
904
905 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
906 nlav = nla_find(attrs, attrlen, RTA_VIA);
907 if (nla && nlav) {
908 NL_SET_ERR_MSG(extack,
909 "Nexthop configuration can not contain both GATEWAY and VIA");
910 return -EINVAL;
911 }
912
913 if (nla) {
914 if (nh->fib_nh_gw_family != AF_INET ||
915 nla_get_in_addr(nla) != nh->fib_nh_gw4)
916 return 1;
917 } else if (nlav) {
918 struct fib_config cfg2;
919 int err;
920
921 err = fib_gw_from_via(&cfg2, nlav, extack);
922 if (err)
923 return err;
924
925 switch (nh->fib_nh_gw_family) {
926 case AF_INET:
927 if (cfg2.fc_gw_family != AF_INET ||
928 cfg2.fc_gw4 != nh->fib_nh_gw4)
929 return 1;
930 break;
931 case AF_INET6:
932 if (cfg2.fc_gw_family != AF_INET6 ||
933 ipv6_addr_cmp(&cfg2.fc_gw6,
934 &nh->fib_nh_gw6))
935 return 1;
936 break;
937 }
938 }
939
940 #ifdef CONFIG_IP_ROUTE_CLASSID
941 nla = nla_find(attrs, attrlen, RTA_FLOW);
942 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
943 return 1;
944 #endif
945 }
946
947 rtnh = rtnh_next(rtnh, &remaining);
948 } endfor_nexthops(fi);
949 #endif
950 return 0;
951 }
952
953 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
954 {
955 struct nlattr *nla;
956 int remaining;
957
958 if (!cfg->fc_mx)
959 return true;
960
961 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
962 int type = nla_type(nla);
963 u32 fi_val, val;
964
965 if (!type)
966 continue;
967 if (type > RTAX_MAX)
968 return false;
969
970 if (type == RTAX_CC_ALGO) {
971 char tmp[TCP_CA_NAME_MAX];
972 bool ecn_ca = false;
973
974 nla_strlcpy(tmp, nla, sizeof(tmp));
975 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
976 } else {
977 if (nla_len(nla) != sizeof(u32))
978 return false;
979 val = nla_get_u32(nla);
980 }
981
982 fi_val = fi->fib_metrics->metrics[type - 1];
983 if (type == RTAX_FEATURES)
984 fi_val &= ~DST_FEATURE_ECN_CA;
985
986 if (fi_val != val)
987 return false;
988 }
989
990 return true;
991 }
992
993 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
994 u32 table, struct netlink_ext_ack *extack)
995 {
996 struct fib6_config cfg = {
997 .fc_table = table,
998 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
999 .fc_ifindex = nh->fib_nh_oif,
1000 .fc_gateway = nh->fib_nh_gw6,
1001 };
1002 struct fib6_nh fib6_nh = {};
1003 int err;
1004
1005 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1006 if (!err) {
1007 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1008 dev_hold(nh->fib_nh_dev);
1009 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1010 nh->fib_nh_scope = RT_SCOPE_LINK;
1011
1012 ipv6_stub->fib6_nh_release(&fib6_nh);
1013 }
1014
1015 return err;
1016 }
1017
1018 /*
1019 * Picture
1020 * -------
1021 *
1022 * Semantics of nexthop is very messy by historical reasons.
1023 * We have to take into account, that:
1024 * a) gateway can be actually local interface address,
1025 * so that gatewayed route is direct.
1026 * b) gateway must be on-link address, possibly
1027 * described not by an ifaddr, but also by a direct route.
1028 * c) If both gateway and interface are specified, they should not
1029 * contradict.
1030 * d) If we use tunnel routes, gateway could be not on-link.
1031 *
1032 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1033 * results in pretty ugly and hairy code with obscure logic.
1034 *
1035 * I chose to generalized it instead, so that the size
1036 * of code does not increase practically, but it becomes
1037 * much more general.
1038 * Every prefix is assigned a "scope" value: "host" is local address,
1039 * "link" is direct route,
1040 * [ ... "site" ... "interior" ... ]
1041 * and "universe" is true gateway route with global meaning.
1042 *
1043 * Every prefix refers to a set of "nexthop"s (gw, oif),
1044 * where gw must have narrower scope. This recursion stops
1045 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1046 * which means that gw is forced to be on link.
1047 *
1048 * Code is still hairy, but now it is apparently logically
1049 * consistent and very flexible. F.e. as by-product it allows
1050 * to co-exists in peace independent exterior and interior
1051 * routing processes.
1052 *
1053 * Normally it looks as following.
1054 *
1055 * {universe prefix} -> (gw, oif) [scope link]
1056 * |
1057 * |-> {link prefix} -> (gw, oif) [scope local]
1058 * |
1059 * |-> {local prefix} (terminal node)
1060 */
1061 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1062 u8 scope, struct netlink_ext_ack *extack)
1063 {
1064 struct net_device *dev;
1065 struct fib_result res;
1066 int err = 0;
1067
1068 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1069 unsigned int addr_type;
1070
1071 if (scope >= RT_SCOPE_LINK) {
1072 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1073 return -EINVAL;
1074 }
1075 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1076 if (!dev) {
1077 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1078 return -ENODEV;
1079 }
1080 if (!(dev->flags & IFF_UP)) {
1081 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1082 return -ENETDOWN;
1083 }
1084 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1085 if (addr_type != RTN_UNICAST) {
1086 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1087 return -EINVAL;
1088 }
1089 if (!netif_carrier_ok(dev))
1090 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1091 nh->fib_nh_dev = dev;
1092 dev_hold(dev);
1093 nh->fib_nh_scope = RT_SCOPE_LINK;
1094 return 0;
1095 }
1096 rcu_read_lock();
1097 {
1098 struct fib_table *tbl = NULL;
1099 struct flowi4 fl4 = {
1100 .daddr = nh->fib_nh_gw4,
1101 .flowi4_scope = scope + 1,
1102 .flowi4_oif = nh->fib_nh_oif,
1103 .flowi4_iif = LOOPBACK_IFINDEX,
1104 };
1105
1106 /* It is not necessary, but requires a bit of thinking */
1107 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1108 fl4.flowi4_scope = RT_SCOPE_LINK;
1109
1110 if (table)
1111 tbl = fib_get_table(net, table);
1112
1113 if (tbl)
1114 err = fib_table_lookup(tbl, &fl4, &res,
1115 FIB_LOOKUP_IGNORE_LINKSTATE |
1116 FIB_LOOKUP_NOREF);
1117
1118 /* on error or if no table given do full lookup. This
1119 * is needed for example when nexthops are in the local
1120 * table rather than the given table
1121 */
1122 if (!tbl || err) {
1123 err = fib_lookup(net, &fl4, &res,
1124 FIB_LOOKUP_IGNORE_LINKSTATE);
1125 }
1126
1127 if (err) {
1128 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1129 goto out;
1130 }
1131 }
1132
1133 err = -EINVAL;
1134 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1135 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1136 goto out;
1137 }
1138 nh->fib_nh_scope = res.scope;
1139 nh->fib_nh_oif = FIB_RES_OIF(res);
1140 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1141 if (!dev) {
1142 NL_SET_ERR_MSG(extack,
1143 "No egress device for nexthop gateway");
1144 goto out;
1145 }
1146 dev_hold(dev);
1147 if (!netif_carrier_ok(dev))
1148 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1149 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1150 out:
1151 rcu_read_unlock();
1152 return err;
1153 }
1154
1155 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1156 struct netlink_ext_ack *extack)
1157 {
1158 struct in_device *in_dev;
1159 int err;
1160
1161 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1162 NL_SET_ERR_MSG(extack,
1163 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1164 return -EINVAL;
1165 }
1166
1167 rcu_read_lock();
1168
1169 err = -ENODEV;
1170 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1171 if (!in_dev)
1172 goto out;
1173 err = -ENETDOWN;
1174 if (!(in_dev->dev->flags & IFF_UP)) {
1175 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1176 goto out;
1177 }
1178
1179 nh->fib_nh_dev = in_dev->dev;
1180 dev_hold(nh->fib_nh_dev);
1181 nh->fib_nh_scope = RT_SCOPE_HOST;
1182 if (!netif_carrier_ok(nh->fib_nh_dev))
1183 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1184 err = 0;
1185 out:
1186 rcu_read_unlock();
1187 return err;
1188 }
1189
1190 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1191 struct netlink_ext_ack *extack)
1192 {
1193 int err;
1194
1195 if (nh->fib_nh_gw_family == AF_INET)
1196 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1197 else if (nh->fib_nh_gw_family == AF_INET6)
1198 err = fib_check_nh_v6_gw(net, nh, table, extack);
1199 else
1200 err = fib_check_nh_nongw(net, nh, extack);
1201
1202 return err;
1203 }
1204
1205 static inline unsigned int fib_laddr_hashfn(__be32 val)
1206 {
1207 unsigned int mask = (fib_info_hash_size - 1);
1208
1209 return ((__force u32)val ^
1210 ((__force u32)val >> 7) ^
1211 ((__force u32)val >> 14)) & mask;
1212 }
1213
1214 static struct hlist_head *fib_info_hash_alloc(int bytes)
1215 {
1216 if (bytes <= PAGE_SIZE)
1217 return kzalloc(bytes, GFP_KERNEL);
1218 else
1219 return (struct hlist_head *)
1220 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1221 get_order(bytes));
1222 }
1223
1224 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1225 {
1226 if (!hash)
1227 return;
1228
1229 if (bytes <= PAGE_SIZE)
1230 kfree(hash);
1231 else
1232 free_pages((unsigned long) hash, get_order(bytes));
1233 }
1234
1235 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1236 struct hlist_head *new_laddrhash,
1237 unsigned int new_size)
1238 {
1239 struct hlist_head *old_info_hash, *old_laddrhash;
1240 unsigned int old_size = fib_info_hash_size;
1241 unsigned int i, bytes;
1242
1243 spin_lock_bh(&fib_info_lock);
1244 old_info_hash = fib_info_hash;
1245 old_laddrhash = fib_info_laddrhash;
1246 fib_info_hash_size = new_size;
1247
1248 for (i = 0; i < old_size; i++) {
1249 struct hlist_head *head = &fib_info_hash[i];
1250 struct hlist_node *n;
1251 struct fib_info *fi;
1252
1253 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1254 struct hlist_head *dest;
1255 unsigned int new_hash;
1256
1257 new_hash = fib_info_hashfn(fi);
1258 dest = &new_info_hash[new_hash];
1259 hlist_add_head(&fi->fib_hash, dest);
1260 }
1261 }
1262 fib_info_hash = new_info_hash;
1263
1264 for (i = 0; i < old_size; i++) {
1265 struct hlist_head *lhead = &fib_info_laddrhash[i];
1266 struct hlist_node *n;
1267 struct fib_info *fi;
1268
1269 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1270 struct hlist_head *ldest;
1271 unsigned int new_hash;
1272
1273 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1274 ldest = &new_laddrhash[new_hash];
1275 hlist_add_head(&fi->fib_lhash, ldest);
1276 }
1277 }
1278 fib_info_laddrhash = new_laddrhash;
1279
1280 spin_unlock_bh(&fib_info_lock);
1281
1282 bytes = old_size * sizeof(struct hlist_head *);
1283 fib_info_hash_free(old_info_hash, bytes);
1284 fib_info_hash_free(old_laddrhash, bytes);
1285 }
1286
1287 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1288 unsigned char scope)
1289 {
1290 struct fib_nh *nh;
1291
1292 if (nhc->nhc_family != AF_INET)
1293 return inet_select_addr(nhc->nhc_dev, 0, scope);
1294
1295 nh = container_of(nhc, struct fib_nh, nh_common);
1296 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1297 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1298
1299 return nh->nh_saddr;
1300 }
1301
1302 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1303 {
1304 struct fib_nh_common *nhc = res->nhc;
1305
1306 if (res->fi->fib_prefsrc)
1307 return res->fi->fib_prefsrc;
1308
1309 if (nhc->nhc_family == AF_INET) {
1310 struct fib_nh *nh;
1311
1312 nh = container_of(nhc, struct fib_nh, nh_common);
1313 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1314 return nh->nh_saddr;
1315 }
1316
1317 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1318 }
1319
1320 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1321 {
1322 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1323 fib_prefsrc != cfg->fc_dst) {
1324 u32 tb_id = cfg->fc_table;
1325 int rc;
1326
1327 if (tb_id == RT_TABLE_MAIN)
1328 tb_id = RT_TABLE_LOCAL;
1329
1330 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1331 fib_prefsrc, tb_id);
1332
1333 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1334 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1335 fib_prefsrc, RT_TABLE_LOCAL);
1336 }
1337
1338 if (rc != RTN_LOCAL)
1339 return false;
1340 }
1341 return true;
1342 }
1343
1344 struct fib_info *fib_create_info(struct fib_config *cfg,
1345 struct netlink_ext_ack *extack)
1346 {
1347 int err;
1348 struct fib_info *fi = NULL;
1349 struct nexthop *nh = NULL;
1350 struct fib_info *ofi;
1351 int nhs = 1;
1352 struct net *net = cfg->fc_nlinfo.nl_net;
1353
1354 if (cfg->fc_type > RTN_MAX)
1355 goto err_inval;
1356
1357 /* Fast check to catch the most weird cases */
1358 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1359 NL_SET_ERR_MSG(extack, "Invalid scope");
1360 goto err_inval;
1361 }
1362
1363 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1364 NL_SET_ERR_MSG(extack,
1365 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1366 goto err_inval;
1367 }
1368
1369 if (cfg->fc_nh_id) {
1370 if (!cfg->fc_mx) {
1371 fi = fib_find_info_nh(net, cfg);
1372 if (fi) {
1373 fi->fib_treeref++;
1374 return fi;
1375 }
1376 }
1377
1378 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1379 if (!nh) {
1380 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1381 goto err_inval;
1382 }
1383 nhs = 0;
1384 }
1385
1386 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1387 if (cfg->fc_mp) {
1388 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1389 if (nhs == 0)
1390 goto err_inval;
1391 }
1392 #endif
1393
1394 err = -ENOBUFS;
1395 if (fib_info_cnt >= fib_info_hash_size) {
1396 unsigned int new_size = fib_info_hash_size << 1;
1397 struct hlist_head *new_info_hash;
1398 struct hlist_head *new_laddrhash;
1399 unsigned int bytes;
1400
1401 if (!new_size)
1402 new_size = 16;
1403 bytes = new_size * sizeof(struct hlist_head *);
1404 new_info_hash = fib_info_hash_alloc(bytes);
1405 new_laddrhash = fib_info_hash_alloc(bytes);
1406 if (!new_info_hash || !new_laddrhash) {
1407 fib_info_hash_free(new_info_hash, bytes);
1408 fib_info_hash_free(new_laddrhash, bytes);
1409 } else
1410 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1411
1412 if (!fib_info_hash_size)
1413 goto failure;
1414 }
1415
1416 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1417 if (!fi)
1418 goto failure;
1419 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1420 cfg->fc_mx_len, extack);
1421 if (IS_ERR(fi->fib_metrics)) {
1422 err = PTR_ERR(fi->fib_metrics);
1423 kfree(fi);
1424 return ERR_PTR(err);
1425 }
1426
1427 fib_info_cnt++;
1428 fi->fib_net = net;
1429 fi->fib_protocol = cfg->fc_protocol;
1430 fi->fib_scope = cfg->fc_scope;
1431 fi->fib_flags = cfg->fc_flags;
1432 fi->fib_priority = cfg->fc_priority;
1433 fi->fib_prefsrc = cfg->fc_prefsrc;
1434 fi->fib_type = cfg->fc_type;
1435 fi->fib_tb_id = cfg->fc_table;
1436
1437 fi->fib_nhs = nhs;
1438 if (nh) {
1439 if (!nexthop_get(nh)) {
1440 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1441 err = -EINVAL;
1442 } else {
1443 err = 0;
1444 fi->nh = nh;
1445 }
1446 } else {
1447 change_nexthops(fi) {
1448 nexthop_nh->nh_parent = fi;
1449 } endfor_nexthops(fi)
1450
1451 if (cfg->fc_mp)
1452 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1453 extack);
1454 else
1455 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1456 }
1457
1458 if (err != 0)
1459 goto failure;
1460
1461 if (fib_props[cfg->fc_type].error) {
1462 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1463 NL_SET_ERR_MSG(extack,
1464 "Gateway, device and multipath can not be specified for this route type");
1465 goto err_inval;
1466 }
1467 goto link_it;
1468 } else {
1469 switch (cfg->fc_type) {
1470 case RTN_UNICAST:
1471 case RTN_LOCAL:
1472 case RTN_BROADCAST:
1473 case RTN_ANYCAST:
1474 case RTN_MULTICAST:
1475 break;
1476 default:
1477 NL_SET_ERR_MSG(extack, "Invalid route type");
1478 goto err_inval;
1479 }
1480 }
1481
1482 if (cfg->fc_scope > RT_SCOPE_HOST) {
1483 NL_SET_ERR_MSG(extack, "Invalid scope");
1484 goto err_inval;
1485 }
1486
1487 if (fi->nh) {
1488 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1489 if (err)
1490 goto failure;
1491 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1492 struct fib_nh *nh = fi->fib_nh;
1493
1494 /* Local address is added. */
1495 if (nhs != 1) {
1496 NL_SET_ERR_MSG(extack,
1497 "Route with host scope can not have multiple nexthops");
1498 goto err_inval;
1499 }
1500 if (nh->fib_nh_gw_family) {
1501 NL_SET_ERR_MSG(extack,
1502 "Route with host scope can not have a gateway");
1503 goto err_inval;
1504 }
1505 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1506 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1507 err = -ENODEV;
1508 if (!nh->fib_nh_dev)
1509 goto failure;
1510 } else {
1511 int linkdown = 0;
1512
1513 change_nexthops(fi) {
1514 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1515 cfg->fc_table, cfg->fc_scope,
1516 extack);
1517 if (err != 0)
1518 goto failure;
1519 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1520 linkdown++;
1521 } endfor_nexthops(fi)
1522 if (linkdown == fi->fib_nhs)
1523 fi->fib_flags |= RTNH_F_LINKDOWN;
1524 }
1525
1526 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1527 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1528 goto err_inval;
1529 }
1530
1531 if (!fi->nh) {
1532 change_nexthops(fi) {
1533 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1534 fi->fib_scope);
1535 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1536 fi->fib_nh_is_v6 = true;
1537 } endfor_nexthops(fi)
1538
1539 fib_rebalance(fi);
1540 }
1541
1542 link_it:
1543 ofi = fib_find_info(fi);
1544 if (ofi) {
1545 fi->fib_dead = 1;
1546 free_fib_info(fi);
1547 ofi->fib_treeref++;
1548 return ofi;
1549 }
1550
1551 fi->fib_treeref++;
1552 refcount_set(&fi->fib_clntref, 1);
1553 spin_lock_bh(&fib_info_lock);
1554 hlist_add_head(&fi->fib_hash,
1555 &fib_info_hash[fib_info_hashfn(fi)]);
1556 if (fi->fib_prefsrc) {
1557 struct hlist_head *head;
1558
1559 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1560 hlist_add_head(&fi->fib_lhash, head);
1561 }
1562 if (fi->nh) {
1563 list_add(&fi->nh_list, &nh->fi_list);
1564 } else {
1565 change_nexthops(fi) {
1566 struct hlist_head *head;
1567 unsigned int hash;
1568
1569 if (!nexthop_nh->fib_nh_dev)
1570 continue;
1571 hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
1572 head = &fib_info_devhash[hash];
1573 hlist_add_head(&nexthop_nh->nh_hash, head);
1574 } endfor_nexthops(fi)
1575 }
1576 spin_unlock_bh(&fib_info_lock);
1577 return fi;
1578
1579 err_inval:
1580 err = -EINVAL;
1581
1582 failure:
1583 if (fi) {
1584 fi->fib_dead = 1;
1585 free_fib_info(fi);
1586 }
1587
1588 return ERR_PTR(err);
1589 }
1590
1591 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1592 u8 rt_family, unsigned char *flags, bool skip_oif)
1593 {
1594 if (nhc->nhc_flags & RTNH_F_DEAD)
1595 *flags |= RTNH_F_DEAD;
1596
1597 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1598 *flags |= RTNH_F_LINKDOWN;
1599
1600 rcu_read_lock();
1601 switch (nhc->nhc_family) {
1602 case AF_INET:
1603 if (ip_ignore_linkdown(nhc->nhc_dev))
1604 *flags |= RTNH_F_DEAD;
1605 break;
1606 case AF_INET6:
1607 if (ip6_ignore_linkdown(nhc->nhc_dev))
1608 *flags |= RTNH_F_DEAD;
1609 break;
1610 }
1611 rcu_read_unlock();
1612 }
1613
1614 switch (nhc->nhc_gw_family) {
1615 case AF_INET:
1616 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1617 goto nla_put_failure;
1618 break;
1619 case AF_INET6:
1620 /* if gateway family does not match nexthop family
1621 * gateway is encoded as RTA_VIA
1622 */
1623 if (rt_family != nhc->nhc_gw_family) {
1624 int alen = sizeof(struct in6_addr);
1625 struct nlattr *nla;
1626 struct rtvia *via;
1627
1628 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1629 if (!nla)
1630 goto nla_put_failure;
1631
1632 via = nla_data(nla);
1633 via->rtvia_family = AF_INET6;
1634 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1635 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1636 &nhc->nhc_gw.ipv6) < 0) {
1637 goto nla_put_failure;
1638 }
1639 break;
1640 }
1641
1642 *flags |= (nhc->nhc_flags & RTNH_F_ONLINK);
1643 if (nhc->nhc_flags & RTNH_F_OFFLOAD)
1644 *flags |= RTNH_F_OFFLOAD;
1645
1646 if (!skip_oif && nhc->nhc_dev &&
1647 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1648 goto nla_put_failure;
1649
1650 if (nhc->nhc_lwtstate &&
1651 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1652 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1653 goto nla_put_failure;
1654
1655 return 0;
1656
1657 nla_put_failure:
1658 return -EMSGSIZE;
1659 }
1660 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1661
1662 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1663 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1664 int nh_weight, u8 rt_family)
1665 {
1666 const struct net_device *dev = nhc->nhc_dev;
1667 struct rtnexthop *rtnh;
1668 unsigned char flags = 0;
1669
1670 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1671 if (!rtnh)
1672 goto nla_put_failure;
1673
1674 rtnh->rtnh_hops = nh_weight - 1;
1675 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1676
1677 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1678 goto nla_put_failure;
1679
1680 rtnh->rtnh_flags = flags;
1681
1682 /* length of rtnetlink header + attributes */
1683 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1684
1685 return 0;
1686
1687 nla_put_failure:
1688 return -EMSGSIZE;
1689 }
1690 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1691 #endif
1692
1693 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1694 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1695 {
1696 struct nlattr *mp;
1697
1698 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1699 if (!mp)
1700 goto nla_put_failure;
1701
1702 if (unlikely(fi->nh)) {
1703 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1704 goto nla_put_failure;
1705 goto mp_end;
1706 }
1707
1708 for_nexthops(fi) {
1709 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1710 AF_INET) < 0)
1711 goto nla_put_failure;
1712 #ifdef CONFIG_IP_ROUTE_CLASSID
1713 if (nh->nh_tclassid &&
1714 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1715 goto nla_put_failure;
1716 #endif
1717 } endfor_nexthops(fi);
1718
1719 mp_end:
1720 nla_nest_end(skb, mp);
1721
1722 return 0;
1723
1724 nla_put_failure:
1725 return -EMSGSIZE;
1726 }
1727 #else
1728 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1729 {
1730 return 0;
1731 }
1732 #endif
1733
1734 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1735 struct fib_rt_info *fri, unsigned int flags)
1736 {
1737 unsigned int nhs = fib_info_num_path(fri->fi);
1738 struct fib_info *fi = fri->fi;
1739 u32 tb_id = fri->tb_id;
1740 struct nlmsghdr *nlh;
1741 struct rtmsg *rtm;
1742
1743 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1744 if (!nlh)
1745 return -EMSGSIZE;
1746
1747 rtm = nlmsg_data(nlh);
1748 rtm->rtm_family = AF_INET;
1749 rtm->rtm_dst_len = fri->dst_len;
1750 rtm->rtm_src_len = 0;
1751 rtm->rtm_tos = fri->tos;
1752 if (tb_id < 256)
1753 rtm->rtm_table = tb_id;
1754 else
1755 rtm->rtm_table = RT_TABLE_COMPAT;
1756 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1757 goto nla_put_failure;
1758 rtm->rtm_type = fri->type;
1759 rtm->rtm_flags = fi->fib_flags;
1760 rtm->rtm_scope = fi->fib_scope;
1761 rtm->rtm_protocol = fi->fib_protocol;
1762
1763 if (rtm->rtm_dst_len &&
1764 nla_put_in_addr(skb, RTA_DST, fri->dst))
1765 goto nla_put_failure;
1766 if (fi->fib_priority &&
1767 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1768 goto nla_put_failure;
1769 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1770 goto nla_put_failure;
1771
1772 if (fi->fib_prefsrc &&
1773 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1774 goto nla_put_failure;
1775
1776 if (fi->nh) {
1777 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1778 goto nla_put_failure;
1779 if (nexthop_is_blackhole(fi->nh))
1780 rtm->rtm_type = RTN_BLACKHOLE;
1781 }
1782
1783 if (nhs == 1) {
1784 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1785 unsigned char flags = 0;
1786
1787 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1788 goto nla_put_failure;
1789
1790 rtm->rtm_flags = flags;
1791 #ifdef CONFIG_IP_ROUTE_CLASSID
1792 if (nhc->nhc_family == AF_INET) {
1793 struct fib_nh *nh;
1794
1795 nh = container_of(nhc, struct fib_nh, nh_common);
1796 if (nh->nh_tclassid &&
1797 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1798 goto nla_put_failure;
1799 }
1800 #endif
1801 } else {
1802 if (fib_add_multipath(skb, fi) < 0)
1803 goto nla_put_failure;
1804 }
1805
1806 if (fri->offload)
1807 rtm->rtm_flags |= RTM_F_OFFLOAD;
1808 if (fri->trap)
1809 rtm->rtm_flags |= RTM_F_TRAP;
1810
1811 nlmsg_end(skb, nlh);
1812 return 0;
1813
1814 nla_put_failure:
1815 nlmsg_cancel(skb, nlh);
1816 return -EMSGSIZE;
1817 }
1818
1819 /*
1820 * Update FIB if:
1821 * - local address disappeared -> we must delete all the entries
1822 * referring to it.
1823 * - device went down -> we must shutdown all nexthops going via it.
1824 */
1825 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1826 {
1827 int ret = 0;
1828 unsigned int hash = fib_laddr_hashfn(local);
1829 struct hlist_head *head = &fib_info_laddrhash[hash];
1830 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1831 struct net *net = dev_net(dev);
1832 struct fib_info *fi;
1833
1834 if (!fib_info_laddrhash || local == 0)
1835 return 0;
1836
1837 hlist_for_each_entry(fi, head, fib_lhash) {
1838 if (!net_eq(fi->fib_net, net) ||
1839 fi->fib_tb_id != tb_id)
1840 continue;
1841 if (fi->fib_prefsrc == local) {
1842 fi->fib_flags |= RTNH_F_DEAD;
1843 ret++;
1844 }
1845 }
1846 return ret;
1847 }
1848
1849 static int call_fib_nh_notifiers(struct fib_nh *nh,
1850 enum fib_event_type event_type)
1851 {
1852 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1853 struct fib_nh_notifier_info info = {
1854 .fib_nh = nh,
1855 };
1856
1857 switch (event_type) {
1858 case FIB_EVENT_NH_ADD:
1859 if (nh->fib_nh_flags & RTNH_F_DEAD)
1860 break;
1861 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1862 break;
1863 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1864 &info.info);
1865 case FIB_EVENT_NH_DEL:
1866 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1867 (nh->fib_nh_flags & RTNH_F_DEAD))
1868 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1869 event_type, &info.info);
1870 default:
1871 break;
1872 }
1873
1874 return NOTIFY_DONE;
1875 }
1876
1877 /* Update the PMTU of exceptions when:
1878 * - the new MTU of the first hop becomes smaller than the PMTU
1879 * - the old MTU was the same as the PMTU, and it limited discovery of
1880 * larger MTUs on the path. With that limit raised, we can now
1881 * discover larger MTUs
1882 * A special case is locked exceptions, for which the PMTU is smaller
1883 * than the minimal accepted PMTU:
1884 * - if the new MTU is greater than the PMTU, don't make any change
1885 * - otherwise, unlock and set PMTU
1886 */
1887 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1888 {
1889 struct fnhe_hash_bucket *bucket;
1890 int i;
1891
1892 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1893 if (!bucket)
1894 return;
1895
1896 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1897 struct fib_nh_exception *fnhe;
1898
1899 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1900 fnhe;
1901 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1902 if (fnhe->fnhe_mtu_locked) {
1903 if (new <= fnhe->fnhe_pmtu) {
1904 fnhe->fnhe_pmtu = new;
1905 fnhe->fnhe_mtu_locked = false;
1906 }
1907 } else if (new < fnhe->fnhe_pmtu ||
1908 orig == fnhe->fnhe_pmtu) {
1909 fnhe->fnhe_pmtu = new;
1910 }
1911 }
1912 }
1913 }
1914
1915 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1916 {
1917 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1918 struct hlist_head *head = &fib_info_devhash[hash];
1919 struct fib_nh *nh;
1920
1921 hlist_for_each_entry(nh, head, nh_hash) {
1922 if (nh->fib_nh_dev == dev)
1923 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1924 }
1925 }
1926
1927 /* Event force Flags Description
1928 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1929 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1930 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1931 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1932 *
1933 * only used when fib_nh is built into fib_info
1934 */
1935 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1936 {
1937 int ret = 0;
1938 int scope = RT_SCOPE_NOWHERE;
1939 struct fib_info *prev_fi = NULL;
1940 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1941 struct hlist_head *head = &fib_info_devhash[hash];
1942 struct fib_nh *nh;
1943
1944 if (force)
1945 scope = -1;
1946
1947 hlist_for_each_entry(nh, head, nh_hash) {
1948 struct fib_info *fi = nh->nh_parent;
1949 int dead;
1950
1951 BUG_ON(!fi->fib_nhs);
1952 if (nh->fib_nh_dev != dev || fi == prev_fi)
1953 continue;
1954 prev_fi = fi;
1955 dead = 0;
1956 change_nexthops(fi) {
1957 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1958 dead++;
1959 else if (nexthop_nh->fib_nh_dev == dev &&
1960 nexthop_nh->fib_nh_scope != scope) {
1961 switch (event) {
1962 case NETDEV_DOWN:
1963 case NETDEV_UNREGISTER:
1964 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1965 /* fall through */
1966 case NETDEV_CHANGE:
1967 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1968 break;
1969 }
1970 call_fib_nh_notifiers(nexthop_nh,
1971 FIB_EVENT_NH_DEL);
1972 dead++;
1973 }
1974 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1975 if (event == NETDEV_UNREGISTER &&
1976 nexthop_nh->fib_nh_dev == dev) {
1977 dead = fi->fib_nhs;
1978 break;
1979 }
1980 #endif
1981 } endfor_nexthops(fi)
1982 if (dead == fi->fib_nhs) {
1983 switch (event) {
1984 case NETDEV_DOWN:
1985 case NETDEV_UNREGISTER:
1986 fi->fib_flags |= RTNH_F_DEAD;
1987 /* fall through */
1988 case NETDEV_CHANGE:
1989 fi->fib_flags |= RTNH_F_LINKDOWN;
1990 break;
1991 }
1992 ret++;
1993 }
1994
1995 fib_rebalance(fi);
1996 }
1997
1998 return ret;
1999 }
2000
2001 /* Must be invoked inside of an RCU protected region. */
2002 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2003 {
2004 struct fib_info *fi = NULL, *last_resort = NULL;
2005 struct hlist_head *fa_head = res->fa_head;
2006 struct fib_table *tb = res->table;
2007 u8 slen = 32 - res->prefixlen;
2008 int order = -1, last_idx = -1;
2009 struct fib_alias *fa, *fa1 = NULL;
2010 u32 last_prio = res->fi->fib_priority;
2011 u8 last_tos = 0;
2012
2013 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2014 struct fib_info *next_fi = fa->fa_info;
2015 struct fib_nh *nh;
2016
2017 if (fa->fa_slen != slen)
2018 continue;
2019 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2020 continue;
2021 if (fa->tb_id != tb->tb_id)
2022 continue;
2023 if (next_fi->fib_priority > last_prio &&
2024 fa->fa_tos == last_tos) {
2025 if (last_tos)
2026 continue;
2027 break;
2028 }
2029 if (next_fi->fib_flags & RTNH_F_DEAD)
2030 continue;
2031 last_tos = fa->fa_tos;
2032 last_prio = next_fi->fib_priority;
2033
2034 if (next_fi->fib_scope != res->scope ||
2035 fa->fa_type != RTN_UNICAST)
2036 continue;
2037
2038 nh = fib_info_nh(next_fi, 0);
2039 if (!nh->fib_nh_gw4 || nh->fib_nh_scope != RT_SCOPE_LINK)
2040 continue;
2041
2042 fib_alias_accessed(fa);
2043
2044 if (!fi) {
2045 if (next_fi != res->fi)
2046 break;
2047 fa1 = fa;
2048 } else if (!fib_detect_death(fi, order, &last_resort,
2049 &last_idx, fa1->fa_default)) {
2050 fib_result_assign(res, fi);
2051 fa1->fa_default = order;
2052 goto out;
2053 }
2054 fi = next_fi;
2055 order++;
2056 }
2057
2058 if (order <= 0 || !fi) {
2059 if (fa1)
2060 fa1->fa_default = -1;
2061 goto out;
2062 }
2063
2064 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2065 fa1->fa_default)) {
2066 fib_result_assign(res, fi);
2067 fa1->fa_default = order;
2068 goto out;
2069 }
2070
2071 if (last_idx >= 0)
2072 fib_result_assign(res, last_resort);
2073 fa1->fa_default = last_idx;
2074 out:
2075 return;
2076 }
2077
2078 /*
2079 * Dead device goes up. We wake up dead nexthops.
2080 * It takes sense only on multipath routes.
2081 *
2082 * only used when fib_nh is built into fib_info
2083 */
2084 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2085 {
2086 struct fib_info *prev_fi;
2087 unsigned int hash;
2088 struct hlist_head *head;
2089 struct fib_nh *nh;
2090 int ret;
2091
2092 if (!(dev->flags & IFF_UP))
2093 return 0;
2094
2095 if (nh_flags & RTNH_F_DEAD) {
2096 unsigned int flags = dev_get_flags(dev);
2097
2098 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2099 nh_flags |= RTNH_F_LINKDOWN;
2100 }
2101
2102 prev_fi = NULL;
2103 hash = fib_devindex_hashfn(dev->ifindex);
2104 head = &fib_info_devhash[hash];
2105 ret = 0;
2106
2107 hlist_for_each_entry(nh, head, nh_hash) {
2108 struct fib_info *fi = nh->nh_parent;
2109 int alive;
2110
2111 BUG_ON(!fi->fib_nhs);
2112 if (nh->fib_nh_dev != dev || fi == prev_fi)
2113 continue;
2114
2115 prev_fi = fi;
2116 alive = 0;
2117 change_nexthops(fi) {
2118 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2119 alive++;
2120 continue;
2121 }
2122 if (!nexthop_nh->fib_nh_dev ||
2123 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2124 continue;
2125 if (nexthop_nh->fib_nh_dev != dev ||
2126 !__in_dev_get_rtnl(dev))
2127 continue;
2128 alive++;
2129 nexthop_nh->fib_nh_flags &= ~nh_flags;
2130 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2131 } endfor_nexthops(fi)
2132
2133 if (alive > 0) {
2134 fi->fib_flags &= ~nh_flags;
2135 ret++;
2136 }
2137
2138 fib_rebalance(fi);
2139 }
2140
2141 return ret;
2142 }
2143
2144 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2145 static bool fib_good_nh(const struct fib_nh *nh)
2146 {
2147 int state = NUD_REACHABLE;
2148
2149 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2150 struct neighbour *n;
2151
2152 rcu_read_lock_bh();
2153
2154 if (likely(nh->fib_nh_gw_family == AF_INET))
2155 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2156 (__force u32)nh->fib_nh_gw4);
2157 else if (nh->fib_nh_gw_family == AF_INET6)
2158 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2159 &nh->fib_nh_gw6);
2160 else
2161 n = NULL;
2162 if (n)
2163 state = n->nud_state;
2164
2165 rcu_read_unlock_bh();
2166 }
2167
2168 return !!(state & NUD_VALID);
2169 }
2170
2171 void fib_select_multipath(struct fib_result *res, int hash)
2172 {
2173 struct fib_info *fi = res->fi;
2174 struct net *net = fi->fib_net;
2175 bool first = false;
2176
2177 if (unlikely(res->fi->nh)) {
2178 nexthop_path_fib_result(res, hash);
2179 return;
2180 }
2181
2182 change_nexthops(fi) {
2183 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2184 if (!fib_good_nh(nexthop_nh))
2185 continue;
2186 if (!first) {
2187 res->nh_sel = nhsel;
2188 res->nhc = &nexthop_nh->nh_common;
2189 first = true;
2190 }
2191 }
2192
2193 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2194 continue;
2195
2196 res->nh_sel = nhsel;
2197 res->nhc = &nexthop_nh->nh_common;
2198 return;
2199 } endfor_nexthops(fi);
2200 }
2201 #endif
2202
2203 void fib_select_path(struct net *net, struct fib_result *res,
2204 struct flowi4 *fl4, const struct sk_buff *skb)
2205 {
2206 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2207 goto check_saddr;
2208
2209 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2210 if (fib_info_num_path(res->fi) > 1) {
2211 int h = fib_multipath_hash(net, fl4, skb, NULL);
2212
2213 fib_select_multipath(res, h);
2214 }
2215 else
2216 #endif
2217 if (!res->prefixlen &&
2218 res->table->tb_num_default > 1 &&
2219 res->type == RTN_UNICAST)
2220 fib_select_default(fl4, res);
2221
2222 check_saddr:
2223 if (!fl4->saddr)
2224 fl4->saddr = fib_result_prefsrc(net, res);
2225 }
Linux with added FPC-III support