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 #include <linux/hash.h>
33 #include <linux/nospec.h>
34
35 #include <net/arp.h>
36 #include <net/inet_dscp.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/ip6_fib.h>
44 #include <net/nexthop.h>
45 #include <net/netlink.h>
46 #include <net/rtnh.h>
47 #include <net/lwtunnel.h>
48 #include <net/fib_notifier.h>
49 #include <net/addrconf.h>
50
51 #include "fib_lookup.h"
52
53 static DEFINE_SPINLOCK(fib_info_lock);
54 static struct hlist_head *fib_info_hash;
55 static struct hlist_head *fib_info_laddrhash;
56 static unsigned int fib_info_hash_size;
57 static unsigned int fib_info_hash_bits;
58 static unsigned int fib_info_cnt;
59
60 #define DEVINDEX_HASHBITS 8
61 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
62 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
63
64 /* for_nexthops and change_nexthops only used when nexthop object
65 * is not set in a fib_info. The logic within can reference fib_nh.
66 */
67 #ifdef CONFIG_IP_ROUTE_MULTIPATH
68
69 #define for_nexthops(fi) { \
70 int nhsel; const struct fib_nh *nh; \
71 for (nhsel = 0, nh = (fi)->fib_nh; \
72 nhsel < fib_info_num_path((fi)); \
73 nh++, nhsel++)
74
75 #define change_nexthops(fi) { \
76 int nhsel; struct fib_nh *nexthop_nh; \
77 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
78 nhsel < fib_info_num_path((fi)); \
79 nexthop_nh++, nhsel++)
80
81 #else /* CONFIG_IP_ROUTE_MULTIPATH */
82
83 /* Hope, that gcc will optimize it to get rid of dummy loop */
84
85 #define for_nexthops(fi) { \
86 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
87 for (nhsel = 0; nhsel < 1; nhsel++)
88
89 #define change_nexthops(fi) { \
90 int nhsel; \
91 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
92 for (nhsel = 0; nhsel < 1; nhsel++)
93
94 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
95
96 #define endfor_nexthops(fi) }
97
98
99 const struct fib_prop fib_props[RTN_MAX + 1] = {
100 [RTN_UNSPEC] = {
101 .error = 0,
102 .scope = RT_SCOPE_NOWHERE,
103 },
104 [RTN_UNICAST] = {
105 .error = 0,
106 .scope = RT_SCOPE_UNIVERSE,
107 },
108 [RTN_LOCAL] = {
109 .error = 0,
110 .scope = RT_SCOPE_HOST,
111 },
112 [RTN_BROADCAST] = {
113 .error = 0,
114 .scope = RT_SCOPE_LINK,
115 },
116 [RTN_ANYCAST] = {
117 .error = 0,
118 .scope = RT_SCOPE_LINK,
119 },
120 [RTN_MULTICAST] = {
121 .error = 0,
122 .scope = RT_SCOPE_UNIVERSE,
123 },
124 [RTN_BLACKHOLE] = {
125 .error = -EINVAL,
126 .scope = RT_SCOPE_UNIVERSE,
127 },
128 [RTN_UNREACHABLE] = {
129 .error = -EHOSTUNREACH,
130 .scope = RT_SCOPE_UNIVERSE,
131 },
132 [RTN_PROHIBIT] = {
133 .error = -EACCES,
134 .scope = RT_SCOPE_UNIVERSE,
135 },
136 [RTN_THROW] = {
137 .error = -EAGAIN,
138 .scope = RT_SCOPE_UNIVERSE,
139 },
140 [RTN_NAT] = {
141 .error = -EINVAL,
142 .scope = RT_SCOPE_NOWHERE,
143 },
144 [RTN_XRESOLVE] = {
145 .error = -EINVAL,
146 .scope = RT_SCOPE_NOWHERE,
147 },
148 };
149
150 static void rt_fibinfo_free(struct rtable __rcu **rtp)
151 {
152 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
153
154 if (!rt)
155 return;
156
157 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
158 * because we waited an RCU grace period before calling
159 * free_fib_info_rcu()
160 */
161
162 dst_dev_put(&rt->dst);
163 dst_release_immediate(&rt->dst);
164 }
165
166 static void free_nh_exceptions(struct fib_nh_common *nhc)
167 {
168 struct fnhe_hash_bucket *hash;
169 int i;
170
171 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
172 if (!hash)
173 return;
174 for (i = 0; i < FNHE_HASH_SIZE; i++) {
175 struct fib_nh_exception *fnhe;
176
177 fnhe = rcu_dereference_protected(hash[i].chain, 1);
178 while (fnhe) {
179 struct fib_nh_exception *next;
180
181 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
182
183 rt_fibinfo_free(&fnhe->fnhe_rth_input);
184 rt_fibinfo_free(&fnhe->fnhe_rth_output);
185
186 kfree(fnhe);
187
188 fnhe = next;
189 }
190 }
191 kfree(hash);
192 }
193
194 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
195 {
196 int cpu;
197
198 if (!rtp)
199 return;
200
201 for_each_possible_cpu(cpu) {
202 struct rtable *rt;
203
204 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
205 if (rt) {
206 dst_dev_put(&rt->dst);
207 dst_release_immediate(&rt->dst);
208 }
209 }
210 free_percpu(rtp);
211 }
212
213 void fib_nh_common_release(struct fib_nh_common *nhc)
214 {
215 netdev_put(nhc->nhc_dev, &nhc->nhc_dev_tracker);
216 lwtstate_put(nhc->nhc_lwtstate);
217 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
218 rt_fibinfo_free(&nhc->nhc_rth_input);
219 free_nh_exceptions(nhc);
220 }
221 EXPORT_SYMBOL_GPL(fib_nh_common_release);
222
223 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
224 {
225 #ifdef CONFIG_IP_ROUTE_CLASSID
226 if (fib_nh->nh_tclassid)
227 atomic_dec(&net->ipv4.fib_num_tclassid_users);
228 #endif
229 fib_nh_common_release(&fib_nh->nh_common);
230 }
231
232 /* Release a nexthop info record */
233 static void free_fib_info_rcu(struct rcu_head *head)
234 {
235 struct fib_info *fi = container_of(head, struct fib_info, rcu);
236
237 if (fi->nh) {
238 nexthop_put(fi->nh);
239 } else {
240 change_nexthops(fi) {
241 fib_nh_release(fi->fib_net, nexthop_nh);
242 } endfor_nexthops(fi);
243 }
244
245 ip_fib_metrics_put(fi->fib_metrics);
246
247 kfree(fi);
248 }
249
250 void free_fib_info(struct fib_info *fi)
251 {
252 if (fi->fib_dead == 0) {
253 pr_warn("Freeing alive fib_info %p\n", fi);
254 return;
255 }
256
257 call_rcu_hurry(&fi->rcu, free_fib_info_rcu);
258 }
259 EXPORT_SYMBOL_GPL(free_fib_info);
260
261 void fib_release_info(struct fib_info *fi)
262 {
263 spin_lock_bh(&fib_info_lock);
264 if (fi && refcount_dec_and_test(&fi->fib_treeref)) {
265 hlist_del(&fi->fib_hash);
266
267 /* Paired with READ_ONCE() in fib_create_info(). */
268 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
269
270 if (fi->fib_prefsrc)
271 hlist_del(&fi->fib_lhash);
272 if (fi->nh) {
273 list_del(&fi->nh_list);
274 } else {
275 change_nexthops(fi) {
276 if (!nexthop_nh->fib_nh_dev)
277 continue;
278 hlist_del(&nexthop_nh->nh_hash);
279 } endfor_nexthops(fi)
280 }
281 /* Paired with READ_ONCE() from fib_table_lookup() */
282 WRITE_ONCE(fi->fib_dead, 1);
283 fib_info_put(fi);
284 }
285 spin_unlock_bh(&fib_info_lock);
286 }
287
288 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
289 {
290 const struct fib_nh *onh;
291
292 if (fi->nh || ofi->nh)
293 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
294
295 if (ofi->fib_nhs == 0)
296 return 0;
297
298 for_nexthops(fi) {
299 onh = fib_info_nh(ofi, nhsel);
300
301 if (nh->fib_nh_oif != onh->fib_nh_oif ||
302 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
303 nh->fib_nh_scope != onh->fib_nh_scope ||
304 #ifdef CONFIG_IP_ROUTE_MULTIPATH
305 nh->fib_nh_weight != onh->fib_nh_weight ||
306 #endif
307 #ifdef CONFIG_IP_ROUTE_CLASSID
308 nh->nh_tclassid != onh->nh_tclassid ||
309 #endif
310 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
311 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
312 return -1;
313
314 if (nh->fib_nh_gw_family == AF_INET &&
315 nh->fib_nh_gw4 != onh->fib_nh_gw4)
316 return -1;
317
318 if (nh->fib_nh_gw_family == AF_INET6 &&
319 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
320 return -1;
321 } endfor_nexthops(fi);
322 return 0;
323 }
324
325 static inline unsigned int fib_devindex_hashfn(unsigned int val)
326 {
327 return hash_32(val, DEVINDEX_HASHBITS);
328 }
329
330 static struct hlist_head *
331 fib_info_devhash_bucket(const struct net_device *dev)
332 {
333 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
334
335 return &fib_info_devhash[fib_devindex_hashfn(val)];
336 }
337
338 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
339 u32 prefsrc, u32 priority)
340 {
341 unsigned int val = init_val;
342
343 val ^= (protocol << 8) | scope;
344 val ^= prefsrc;
345 val ^= priority;
346
347 return val;
348 }
349
350 static unsigned int fib_info_hashfn_result(unsigned int val)
351 {
352 unsigned int mask = (fib_info_hash_size - 1);
353
354 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
355 }
356
357 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
358 {
359 unsigned int val;
360
361 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
362 fi->fib_scope, (__force u32)fi->fib_prefsrc,
363 fi->fib_priority);
364
365 if (fi->nh) {
366 val ^= fib_devindex_hashfn(fi->nh->id);
367 } else {
368 for_nexthops(fi) {
369 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
370 } endfor_nexthops(fi)
371 }
372
373 return fib_info_hashfn_result(val);
374 }
375
376 /* no metrics, only nexthop id */
377 static struct fib_info *fib_find_info_nh(struct net *net,
378 const struct fib_config *cfg)
379 {
380 struct hlist_head *head;
381 struct fib_info *fi;
382 unsigned int hash;
383
384 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
385 cfg->fc_protocol, cfg->fc_scope,
386 (__force u32)cfg->fc_prefsrc,
387 cfg->fc_priority);
388 hash = fib_info_hashfn_result(hash);
389 head = &fib_info_hash[hash];
390
391 hlist_for_each_entry(fi, head, fib_hash) {
392 if (!net_eq(fi->fib_net, net))
393 continue;
394 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
395 continue;
396 if (cfg->fc_protocol == fi->fib_protocol &&
397 cfg->fc_scope == fi->fib_scope &&
398 cfg->fc_prefsrc == fi->fib_prefsrc &&
399 cfg->fc_priority == fi->fib_priority &&
400 cfg->fc_type == fi->fib_type &&
401 cfg->fc_table == fi->fib_tb_id &&
402 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
403 return fi;
404 }
405
406 return NULL;
407 }
408
409 static struct fib_info *fib_find_info(struct fib_info *nfi)
410 {
411 struct hlist_head *head;
412 struct fib_info *fi;
413 unsigned int hash;
414
415 hash = fib_info_hashfn(nfi);
416 head = &fib_info_hash[hash];
417
418 hlist_for_each_entry(fi, head, fib_hash) {
419 if (!net_eq(fi->fib_net, nfi->fib_net))
420 continue;
421 if (fi->fib_nhs != nfi->fib_nhs)
422 continue;
423 if (nfi->fib_protocol == fi->fib_protocol &&
424 nfi->fib_scope == fi->fib_scope &&
425 nfi->fib_prefsrc == fi->fib_prefsrc &&
426 nfi->fib_priority == fi->fib_priority &&
427 nfi->fib_type == fi->fib_type &&
428 nfi->fib_tb_id == fi->fib_tb_id &&
429 memcmp(nfi->fib_metrics, fi->fib_metrics,
430 sizeof(u32) * RTAX_MAX) == 0 &&
431 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
432 nh_comp(fi, nfi) == 0)
433 return fi;
434 }
435
436 return NULL;
437 }
438
439 /* Check, that the gateway is already configured.
440 * Used only by redirect accept routine.
441 */
442 int ip_fib_check_default(__be32 gw, struct net_device *dev)
443 {
444 struct hlist_head *head;
445 struct fib_nh *nh;
446
447 spin_lock(&fib_info_lock);
448
449 head = fib_info_devhash_bucket(dev);
450
451 hlist_for_each_entry(nh, head, nh_hash) {
452 if (nh->fib_nh_dev == dev &&
453 nh->fib_nh_gw4 == gw &&
454 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
455 spin_unlock(&fib_info_lock);
456 return 0;
457 }
458 }
459
460 spin_unlock(&fib_info_lock);
461
462 return -1;
463 }
464
465 size_t fib_nlmsg_size(struct fib_info *fi)
466 {
467 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
468 + nla_total_size(4) /* RTA_TABLE */
469 + nla_total_size(4) /* RTA_DST */
470 + nla_total_size(4) /* RTA_PRIORITY */
471 + nla_total_size(4) /* RTA_PREFSRC */
472 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
473 unsigned int nhs = fib_info_num_path(fi);
474
475 /* space for nested metrics */
476 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
477
478 if (fi->nh)
479 payload += nla_total_size(4); /* RTA_NH_ID */
480
481 if (nhs) {
482 size_t nh_encapsize = 0;
483 /* Also handles the special case nhs == 1 */
484
485 /* each nexthop is packed in an attribute */
486 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
487 unsigned int i;
488
489 /* may contain flow and gateway attribute */
490 nhsize += 2 * nla_total_size(4);
491
492 /* grab encap info */
493 for (i = 0; i < fib_info_num_path(fi); i++) {
494 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
495
496 if (nhc->nhc_lwtstate) {
497 /* RTA_ENCAP_TYPE */
498 nh_encapsize += lwtunnel_get_encap_size(
499 nhc->nhc_lwtstate);
500 /* RTA_ENCAP */
501 nh_encapsize += nla_total_size(2);
502 }
503 }
504
505 /* all nexthops are packed in a nested attribute */
506 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
507
508 }
509
510 return payload;
511 }
512
513 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
514 int dst_len, u32 tb_id, const struct nl_info *info,
515 unsigned int nlm_flags)
516 {
517 struct fib_rt_info fri;
518 struct sk_buff *skb;
519 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
520 int err = -ENOBUFS;
521
522 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
523 if (!skb)
524 goto errout;
525
526 fri.fi = fa->fa_info;
527 fri.tb_id = tb_id;
528 fri.dst = key;
529 fri.dst_len = dst_len;
530 fri.dscp = fa->fa_dscp;
531 fri.type = fa->fa_type;
532 fri.offload = READ_ONCE(fa->offload);
533 fri.trap = READ_ONCE(fa->trap);
534 fri.offload_failed = READ_ONCE(fa->offload_failed);
535 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
536 if (err < 0) {
537 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
538 WARN_ON(err == -EMSGSIZE);
539 kfree_skb(skb);
540 goto errout;
541 }
542 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
543 info->nlh, GFP_KERNEL);
544 return;
545 errout:
546 if (err < 0)
547 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
548 }
549
550 static int fib_detect_death(struct fib_info *fi, int order,
551 struct fib_info **last_resort, int *last_idx,
552 int dflt)
553 {
554 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
555 struct neighbour *n;
556 int state = NUD_NONE;
557
558 if (likely(nhc->nhc_gw_family == AF_INET))
559 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
560 else if (nhc->nhc_gw_family == AF_INET6)
561 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
562 nhc->nhc_dev);
563 else
564 n = NULL;
565
566 if (n) {
567 state = READ_ONCE(n->nud_state);
568 neigh_release(n);
569 } else {
570 return 0;
571 }
572 if (state == NUD_REACHABLE)
573 return 0;
574 if ((state & NUD_VALID) && order != dflt)
575 return 0;
576 if ((state & NUD_VALID) ||
577 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
578 *last_resort = fi;
579 *last_idx = order;
580 }
581 return 1;
582 }
583
584 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
585 struct nlattr *encap, u16 encap_type,
586 void *cfg, gfp_t gfp_flags,
587 struct netlink_ext_ack *extack)
588 {
589 int err;
590
591 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
592 gfp_flags);
593 if (!nhc->nhc_pcpu_rth_output)
594 return -ENOMEM;
595
596 if (encap) {
597 struct lwtunnel_state *lwtstate;
598
599 if (encap_type == LWTUNNEL_ENCAP_NONE) {
600 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
601 err = -EINVAL;
602 goto lwt_failure;
603 }
604 err = lwtunnel_build_state(net, encap_type, encap,
605 nhc->nhc_family, cfg, &lwtstate,
606 extack);
607 if (err)
608 goto lwt_failure;
609
610 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
611 }
612
613 return 0;
614
615 lwt_failure:
616 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
617 nhc->nhc_pcpu_rth_output = NULL;
618 return err;
619 }
620 EXPORT_SYMBOL_GPL(fib_nh_common_init);
621
622 int fib_nh_init(struct net *net, struct fib_nh *nh,
623 struct fib_config *cfg, int nh_weight,
624 struct netlink_ext_ack *extack)
625 {
626 int err;
627
628 nh->fib_nh_family = AF_INET;
629
630 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
631 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
632 if (err)
633 return err;
634
635 nh->fib_nh_oif = cfg->fc_oif;
636 nh->fib_nh_gw_family = cfg->fc_gw_family;
637 if (cfg->fc_gw_family == AF_INET)
638 nh->fib_nh_gw4 = cfg->fc_gw4;
639 else if (cfg->fc_gw_family == AF_INET6)
640 nh->fib_nh_gw6 = cfg->fc_gw6;
641
642 nh->fib_nh_flags = cfg->fc_flags;
643
644 #ifdef CONFIG_IP_ROUTE_CLASSID
645 nh->nh_tclassid = cfg->fc_flow;
646 if (nh->nh_tclassid)
647 atomic_inc(&net->ipv4.fib_num_tclassid_users);
648 #endif
649 #ifdef CONFIG_IP_ROUTE_MULTIPATH
650 nh->fib_nh_weight = nh_weight;
651 #endif
652 return 0;
653 }
654
655 #ifdef CONFIG_IP_ROUTE_MULTIPATH
656
657 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
658 struct netlink_ext_ack *extack)
659 {
660 int nhs = 0;
661
662 while (rtnh_ok(rtnh, remaining)) {
663 nhs++;
664 rtnh = rtnh_next(rtnh, &remaining);
665 }
666
667 /* leftover implies invalid nexthop configuration, discard it */
668 if (remaining > 0) {
669 NL_SET_ERR_MSG(extack,
670 "Invalid nexthop configuration - extra data after nexthops");
671 nhs = 0;
672 }
673
674 return nhs;
675 }
676
677 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
678 struct netlink_ext_ack *extack)
679 {
680 if (nla_len(nla) < sizeof(*gw)) {
681 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
682 return -EINVAL;
683 }
684
685 *gw = nla_get_in_addr(nla);
686
687 return 0;
688 }
689
690 /* only called when fib_nh is integrated into fib_info */
691 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
692 int remaining, struct fib_config *cfg,
693 struct netlink_ext_ack *extack)
694 {
695 struct net *net = fi->fib_net;
696 struct fib_config fib_cfg;
697 struct fib_nh *nh;
698 int ret;
699
700 change_nexthops(fi) {
701 int attrlen;
702
703 memset(&fib_cfg, 0, sizeof(fib_cfg));
704
705 if (!rtnh_ok(rtnh, remaining)) {
706 NL_SET_ERR_MSG(extack,
707 "Invalid nexthop configuration - extra data after nexthop");
708 return -EINVAL;
709 }
710
711 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
712 NL_SET_ERR_MSG(extack,
713 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
714 return -EINVAL;
715 }
716
717 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
718 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
719
720 attrlen = rtnh_attrlen(rtnh);
721 if (attrlen > 0) {
722 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
723
724 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
725 nlav = nla_find(attrs, attrlen, RTA_VIA);
726 if (nla && nlav) {
727 NL_SET_ERR_MSG(extack,
728 "Nexthop configuration can not contain both GATEWAY and VIA");
729 return -EINVAL;
730 }
731 if (nla) {
732 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
733 extack);
734 if (ret)
735 goto errout;
736
737 if (fib_cfg.fc_gw4)
738 fib_cfg.fc_gw_family = AF_INET;
739 } else if (nlav) {
740 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
741 if (ret)
742 goto errout;
743 }
744
745 nla = nla_find(attrs, attrlen, RTA_FLOW);
746 if (nla) {
747 if (nla_len(nla) < sizeof(u32)) {
748 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
749 return -EINVAL;
750 }
751 fib_cfg.fc_flow = nla_get_u32(nla);
752 }
753
754 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
755 /* RTA_ENCAP_TYPE length checked in
756 * lwtunnel_valid_encap_type_attr
757 */
758 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
759 if (nla)
760 fib_cfg.fc_encap_type = nla_get_u16(nla);
761 }
762
763 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
764 rtnh->rtnh_hops + 1, extack);
765 if (ret)
766 goto errout;
767
768 rtnh = rtnh_next(rtnh, &remaining);
769 } endfor_nexthops(fi);
770
771 ret = -EINVAL;
772 nh = fib_info_nh(fi, 0);
773 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
774 NL_SET_ERR_MSG(extack,
775 "Nexthop device index does not match RTA_OIF");
776 goto errout;
777 }
778 if (cfg->fc_gw_family) {
779 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
780 (cfg->fc_gw_family == AF_INET &&
781 nh->fib_nh_gw4 != cfg->fc_gw4) ||
782 (cfg->fc_gw_family == AF_INET6 &&
783 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
784 NL_SET_ERR_MSG(extack,
785 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
786 goto errout;
787 }
788 }
789 #ifdef CONFIG_IP_ROUTE_CLASSID
790 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
791 NL_SET_ERR_MSG(extack,
792 "Nexthop class id does not match RTA_FLOW");
793 goto errout;
794 }
795 #endif
796 ret = 0;
797 errout:
798 return ret;
799 }
800
801 /* only called when fib_nh is integrated into fib_info */
802 static void fib_rebalance(struct fib_info *fi)
803 {
804 int total;
805 int w;
806
807 if (fib_info_num_path(fi) < 2)
808 return;
809
810 total = 0;
811 for_nexthops(fi) {
812 if (nh->fib_nh_flags & RTNH_F_DEAD)
813 continue;
814
815 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
816 nh->fib_nh_flags & RTNH_F_LINKDOWN)
817 continue;
818
819 total += nh->fib_nh_weight;
820 } endfor_nexthops(fi);
821
822 w = 0;
823 change_nexthops(fi) {
824 int upper_bound;
825
826 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
827 upper_bound = -1;
828 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
829 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
830 upper_bound = -1;
831 } else {
832 w += nexthop_nh->fib_nh_weight;
833 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
834 total) - 1;
835 }
836
837 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
838 } endfor_nexthops(fi);
839 }
840 #else /* CONFIG_IP_ROUTE_MULTIPATH */
841
842 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
843 int remaining, struct fib_config *cfg,
844 struct netlink_ext_ack *extack)
845 {
846 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
847
848 return -EINVAL;
849 }
850
851 #define fib_rebalance(fi) do { } while (0)
852
853 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
854
855 static int fib_encap_match(struct net *net, u16 encap_type,
856 struct nlattr *encap,
857 const struct fib_nh *nh,
858 const struct fib_config *cfg,
859 struct netlink_ext_ack *extack)
860 {
861 struct lwtunnel_state *lwtstate;
862 int ret, result = 0;
863
864 if (encap_type == LWTUNNEL_ENCAP_NONE)
865 return 0;
866
867 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
868 cfg, &lwtstate, extack);
869 if (!ret) {
870 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
871 lwtstate_free(lwtstate);
872 }
873
874 return result;
875 }
876
877 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
878 struct netlink_ext_ack *extack)
879 {
880 #ifdef CONFIG_IP_ROUTE_MULTIPATH
881 struct rtnexthop *rtnh;
882 int remaining;
883 #endif
884
885 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
886 return 1;
887
888 if (cfg->fc_nh_id) {
889 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
890 return 0;
891 return 1;
892 }
893
894 if (fi->nh) {
895 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
896 return 1;
897 return 0;
898 }
899
900 if (cfg->fc_oif || cfg->fc_gw_family) {
901 struct fib_nh *nh;
902
903 nh = fib_info_nh(fi, 0);
904 if (cfg->fc_encap) {
905 if (fib_encap_match(net, cfg->fc_encap_type,
906 cfg->fc_encap, nh, cfg, extack))
907 return 1;
908 }
909 #ifdef CONFIG_IP_ROUTE_CLASSID
910 if (cfg->fc_flow &&
911 cfg->fc_flow != nh->nh_tclassid)
912 return 1;
913 #endif
914 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
915 (cfg->fc_gw_family &&
916 cfg->fc_gw_family != nh->fib_nh_gw_family))
917 return 1;
918
919 if (cfg->fc_gw_family == AF_INET &&
920 cfg->fc_gw4 != nh->fib_nh_gw4)
921 return 1;
922
923 if (cfg->fc_gw_family == AF_INET6 &&
924 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
925 return 1;
926
927 return 0;
928 }
929
930 #ifdef CONFIG_IP_ROUTE_MULTIPATH
931 if (!cfg->fc_mp)
932 return 0;
933
934 rtnh = cfg->fc_mp;
935 remaining = cfg->fc_mp_len;
936
937 for_nexthops(fi) {
938 int attrlen;
939
940 if (!rtnh_ok(rtnh, remaining))
941 return -EINVAL;
942
943 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
944 return 1;
945
946 attrlen = rtnh_attrlen(rtnh);
947 if (attrlen > 0) {
948 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
949 int err;
950
951 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
952 nlav = nla_find(attrs, attrlen, RTA_VIA);
953 if (nla && nlav) {
954 NL_SET_ERR_MSG(extack,
955 "Nexthop configuration can not contain both GATEWAY and VIA");
956 return -EINVAL;
957 }
958
959 if (nla) {
960 __be32 gw;
961
962 err = fib_gw_from_attr(&gw, nla, extack);
963 if (err)
964 return err;
965
966 if (nh->fib_nh_gw_family != AF_INET ||
967 gw != nh->fib_nh_gw4)
968 return 1;
969 } else if (nlav) {
970 struct fib_config cfg2;
971
972 err = fib_gw_from_via(&cfg2, nlav, extack);
973 if (err)
974 return err;
975
976 switch (nh->fib_nh_gw_family) {
977 case AF_INET:
978 if (cfg2.fc_gw_family != AF_INET ||
979 cfg2.fc_gw4 != nh->fib_nh_gw4)
980 return 1;
981 break;
982 case AF_INET6:
983 if (cfg2.fc_gw_family != AF_INET6 ||
984 ipv6_addr_cmp(&cfg2.fc_gw6,
985 &nh->fib_nh_gw6))
986 return 1;
987 break;
988 }
989 }
990
991 #ifdef CONFIG_IP_ROUTE_CLASSID
992 nla = nla_find(attrs, attrlen, RTA_FLOW);
993 if (nla) {
994 if (nla_len(nla) < sizeof(u32)) {
995 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
996 return -EINVAL;
997 }
998 if (nla_get_u32(nla) != nh->nh_tclassid)
999 return 1;
1000 }
1001 #endif
1002 }
1003
1004 rtnh = rtnh_next(rtnh, &remaining);
1005 } endfor_nexthops(fi);
1006 #endif
1007 return 0;
1008 }
1009
1010 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1011 {
1012 struct nlattr *nla;
1013 int remaining;
1014
1015 if (!cfg->fc_mx)
1016 return true;
1017
1018 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1019 int type = nla_type(nla);
1020 u32 fi_val, val;
1021
1022 if (!type)
1023 continue;
1024 if (type > RTAX_MAX)
1025 return false;
1026
1027 type = array_index_nospec(type, RTAX_MAX + 1);
1028 if (type == RTAX_CC_ALGO) {
1029 char tmp[TCP_CA_NAME_MAX];
1030 bool ecn_ca = false;
1031
1032 nla_strscpy(tmp, nla, sizeof(tmp));
1033 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
1034 } else {
1035 if (nla_len(nla) != sizeof(u32))
1036 return false;
1037 val = nla_get_u32(nla);
1038 }
1039
1040 fi_val = fi->fib_metrics->metrics[type - 1];
1041 if (type == RTAX_FEATURES)
1042 fi_val &= ~DST_FEATURE_ECN_CA;
1043
1044 if (fi_val != val)
1045 return false;
1046 }
1047
1048 return true;
1049 }
1050
1051 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1052 u32 table, struct netlink_ext_ack *extack)
1053 {
1054 struct fib6_config cfg = {
1055 .fc_table = table,
1056 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1057 .fc_ifindex = nh->fib_nh_oif,
1058 .fc_gateway = nh->fib_nh_gw6,
1059 };
1060 struct fib6_nh fib6_nh = {};
1061 int err;
1062
1063 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1064 if (!err) {
1065 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1066 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1067 GFP_KERNEL);
1068 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1069 nh->fib_nh_scope = RT_SCOPE_LINK;
1070
1071 ipv6_stub->fib6_nh_release(&fib6_nh);
1072 }
1073
1074 return err;
1075 }
1076
1077 /*
1078 * Picture
1079 * -------
1080 *
1081 * Semantics of nexthop is very messy by historical reasons.
1082 * We have to take into account, that:
1083 * a) gateway can be actually local interface address,
1084 * so that gatewayed route is direct.
1085 * b) gateway must be on-link address, possibly
1086 * described not by an ifaddr, but also by a direct route.
1087 * c) If both gateway and interface are specified, they should not
1088 * contradict.
1089 * d) If we use tunnel routes, gateway could be not on-link.
1090 *
1091 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1092 * results in pretty ugly and hairy code with obscure logic.
1093 *
1094 * I chose to generalized it instead, so that the size
1095 * of code does not increase practically, but it becomes
1096 * much more general.
1097 * Every prefix is assigned a "scope" value: "host" is local address,
1098 * "link" is direct route,
1099 * [ ... "site" ... "interior" ... ]
1100 * and "universe" is true gateway route with global meaning.
1101 *
1102 * Every prefix refers to a set of "nexthop"s (gw, oif),
1103 * where gw must have narrower scope. This recursion stops
1104 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1105 * which means that gw is forced to be on link.
1106 *
1107 * Code is still hairy, but now it is apparently logically
1108 * consistent and very flexible. F.e. as by-product it allows
1109 * to co-exists in peace independent exterior and interior
1110 * routing processes.
1111 *
1112 * Normally it looks as following.
1113 *
1114 * {universe prefix} -> (gw, oif) [scope link]
1115 * |
1116 * |-> {link prefix} -> (gw, oif) [scope local]
1117 * |
1118 * |-> {local prefix} (terminal node)
1119 */
1120 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1121 u8 scope, struct netlink_ext_ack *extack)
1122 {
1123 struct net_device *dev;
1124 struct fib_result res;
1125 int err = 0;
1126
1127 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1128 unsigned int addr_type;
1129
1130 if (scope >= RT_SCOPE_LINK) {
1131 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1132 return -EINVAL;
1133 }
1134 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1135 if (!dev) {
1136 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1137 return -ENODEV;
1138 }
1139 if (!(dev->flags & IFF_UP)) {
1140 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1141 return -ENETDOWN;
1142 }
1143 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1144 if (addr_type != RTN_UNICAST) {
1145 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1146 return -EINVAL;
1147 }
1148 if (!netif_carrier_ok(dev))
1149 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1150 nh->fib_nh_dev = dev;
1151 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1152 nh->fib_nh_scope = RT_SCOPE_LINK;
1153 return 0;
1154 }
1155 rcu_read_lock();
1156 {
1157 struct fib_table *tbl = NULL;
1158 struct flowi4 fl4 = {
1159 .daddr = nh->fib_nh_gw4,
1160 .flowi4_scope = scope + 1,
1161 .flowi4_oif = nh->fib_nh_oif,
1162 .flowi4_iif = LOOPBACK_IFINDEX,
1163 };
1164
1165 /* It is not necessary, but requires a bit of thinking */
1166 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1167 fl4.flowi4_scope = RT_SCOPE_LINK;
1168
1169 if (table && table != RT_TABLE_MAIN)
1170 tbl = fib_get_table(net, table);
1171
1172 if (tbl)
1173 err = fib_table_lookup(tbl, &fl4, &res,
1174 FIB_LOOKUP_IGNORE_LINKSTATE |
1175 FIB_LOOKUP_NOREF);
1176
1177 /* on error or if no table given do full lookup. This
1178 * is needed for example when nexthops are in the local
1179 * table rather than the given table
1180 */
1181 if (!tbl || err) {
1182 err = fib_lookup(net, &fl4, &res,
1183 FIB_LOOKUP_IGNORE_LINKSTATE);
1184 }
1185
1186 if (err) {
1187 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1188 goto out;
1189 }
1190 }
1191
1192 err = -EINVAL;
1193 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1194 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1195 goto out;
1196 }
1197 nh->fib_nh_scope = res.scope;
1198 nh->fib_nh_oif = FIB_RES_OIF(res);
1199 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1200 if (!dev) {
1201 NL_SET_ERR_MSG(extack,
1202 "No egress device for nexthop gateway");
1203 goto out;
1204 }
1205 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1206 if (!netif_carrier_ok(dev))
1207 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1208 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1209 out:
1210 rcu_read_unlock();
1211 return err;
1212 }
1213
1214 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1215 struct netlink_ext_ack *extack)
1216 {
1217 struct in_device *in_dev;
1218 int err;
1219
1220 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1221 NL_SET_ERR_MSG(extack,
1222 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1223 return -EINVAL;
1224 }
1225
1226 rcu_read_lock();
1227
1228 err = -ENODEV;
1229 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1230 if (!in_dev)
1231 goto out;
1232 err = -ENETDOWN;
1233 if (!(in_dev->dev->flags & IFF_UP)) {
1234 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1235 goto out;
1236 }
1237
1238 nh->fib_nh_dev = in_dev->dev;
1239 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1240 nh->fib_nh_scope = RT_SCOPE_HOST;
1241 if (!netif_carrier_ok(nh->fib_nh_dev))
1242 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1243 err = 0;
1244 out:
1245 rcu_read_unlock();
1246 return err;
1247 }
1248
1249 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1250 struct netlink_ext_ack *extack)
1251 {
1252 int err;
1253
1254 if (nh->fib_nh_gw_family == AF_INET)
1255 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1256 else if (nh->fib_nh_gw_family == AF_INET6)
1257 err = fib_check_nh_v6_gw(net, nh, table, extack);
1258 else
1259 err = fib_check_nh_nongw(net, nh, extack);
1260
1261 return err;
1262 }
1263
1264 static struct hlist_head *
1265 fib_info_laddrhash_bucket(const struct net *net, __be32 val)
1266 {
1267 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val,
1268 fib_info_hash_bits);
1269
1270 return &fib_info_laddrhash[slot];
1271 }
1272
1273 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1274 struct hlist_head *new_laddrhash,
1275 unsigned int new_size)
1276 {
1277 struct hlist_head *old_info_hash, *old_laddrhash;
1278 unsigned int old_size = fib_info_hash_size;
1279 unsigned int i;
1280
1281 spin_lock_bh(&fib_info_lock);
1282 old_info_hash = fib_info_hash;
1283 old_laddrhash = fib_info_laddrhash;
1284 fib_info_hash_size = new_size;
1285 fib_info_hash_bits = ilog2(new_size);
1286
1287 for (i = 0; i < old_size; i++) {
1288 struct hlist_head *head = &fib_info_hash[i];
1289 struct hlist_node *n;
1290 struct fib_info *fi;
1291
1292 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1293 struct hlist_head *dest;
1294 unsigned int new_hash;
1295
1296 new_hash = fib_info_hashfn(fi);
1297 dest = &new_info_hash[new_hash];
1298 hlist_add_head(&fi->fib_hash, dest);
1299 }
1300 }
1301 fib_info_hash = new_info_hash;
1302
1303 fib_info_laddrhash = new_laddrhash;
1304 for (i = 0; i < old_size; i++) {
1305 struct hlist_head *lhead = &old_laddrhash[i];
1306 struct hlist_node *n;
1307 struct fib_info *fi;
1308
1309 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1310 struct hlist_head *ldest;
1311
1312 ldest = fib_info_laddrhash_bucket(fi->fib_net,
1313 fi->fib_prefsrc);
1314 hlist_add_head(&fi->fib_lhash, ldest);
1315 }
1316 }
1317
1318 spin_unlock_bh(&fib_info_lock);
1319
1320 kvfree(old_info_hash);
1321 kvfree(old_laddrhash);
1322 }
1323
1324 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1325 unsigned char scope)
1326 {
1327 struct fib_nh *nh;
1328 __be32 saddr;
1329
1330 if (nhc->nhc_family != AF_INET)
1331 return inet_select_addr(nhc->nhc_dev, 0, scope);
1332
1333 nh = container_of(nhc, struct fib_nh, nh_common);
1334 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1335
1336 WRITE_ONCE(nh->nh_saddr, saddr);
1337 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid));
1338
1339 return saddr;
1340 }
1341
1342 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1343 {
1344 struct fib_nh_common *nhc = res->nhc;
1345
1346 if (res->fi->fib_prefsrc)
1347 return res->fi->fib_prefsrc;
1348
1349 if (nhc->nhc_family == AF_INET) {
1350 struct fib_nh *nh;
1351
1352 nh = container_of(nhc, struct fib_nh, nh_common);
1353 if (READ_ONCE(nh->nh_saddr_genid) ==
1354 atomic_read(&net->ipv4.dev_addr_genid))
1355 return READ_ONCE(nh->nh_saddr);
1356 }
1357
1358 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1359 }
1360
1361 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1362 {
1363 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1364 fib_prefsrc != cfg->fc_dst) {
1365 u32 tb_id = cfg->fc_table;
1366 int rc;
1367
1368 if (tb_id == RT_TABLE_MAIN)
1369 tb_id = RT_TABLE_LOCAL;
1370
1371 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1372 fib_prefsrc, tb_id);
1373
1374 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1375 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1376 fib_prefsrc, RT_TABLE_LOCAL);
1377 }
1378
1379 if (rc != RTN_LOCAL)
1380 return false;
1381 }
1382 return true;
1383 }
1384
1385 struct fib_info *fib_create_info(struct fib_config *cfg,
1386 struct netlink_ext_ack *extack)
1387 {
1388 int err;
1389 struct fib_info *fi = NULL;
1390 struct nexthop *nh = NULL;
1391 struct fib_info *ofi;
1392 int nhs = 1;
1393 struct net *net = cfg->fc_nlinfo.nl_net;
1394
1395 if (cfg->fc_type > RTN_MAX)
1396 goto err_inval;
1397
1398 /* Fast check to catch the most weird cases */
1399 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1400 NL_SET_ERR_MSG(extack, "Invalid scope");
1401 goto err_inval;
1402 }
1403
1404 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1405 NL_SET_ERR_MSG(extack,
1406 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1407 goto err_inval;
1408 }
1409
1410 if (cfg->fc_nh_id) {
1411 if (!cfg->fc_mx) {
1412 fi = fib_find_info_nh(net, cfg);
1413 if (fi) {
1414 refcount_inc(&fi->fib_treeref);
1415 return fi;
1416 }
1417 }
1418
1419 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1420 if (!nh) {
1421 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1422 goto err_inval;
1423 }
1424 nhs = 0;
1425 }
1426
1427 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1428 if (cfg->fc_mp) {
1429 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1430 if (nhs == 0)
1431 goto err_inval;
1432 }
1433 #endif
1434
1435 err = -ENOBUFS;
1436
1437 /* Paired with WRITE_ONCE() in fib_release_info() */
1438 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) {
1439 unsigned int new_size = fib_info_hash_size << 1;
1440 struct hlist_head *new_info_hash;
1441 struct hlist_head *new_laddrhash;
1442 size_t bytes;
1443
1444 if (!new_size)
1445 new_size = 16;
1446 bytes = (size_t)new_size * sizeof(struct hlist_head *);
1447 new_info_hash = kvzalloc(bytes, GFP_KERNEL);
1448 new_laddrhash = kvzalloc(bytes, GFP_KERNEL);
1449 if (!new_info_hash || !new_laddrhash) {
1450 kvfree(new_info_hash);
1451 kvfree(new_laddrhash);
1452 } else {
1453 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1454 }
1455 if (!fib_info_hash_size)
1456 goto failure;
1457 }
1458
1459 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1460 if (!fi)
1461 goto failure;
1462 fi->fib_metrics = ip_fib_metrics_init(cfg->fc_mx, cfg->fc_mx_len, extack);
1463 if (IS_ERR(fi->fib_metrics)) {
1464 err = PTR_ERR(fi->fib_metrics);
1465 kfree(fi);
1466 return ERR_PTR(err);
1467 }
1468
1469 fi->fib_net = net;
1470 fi->fib_protocol = cfg->fc_protocol;
1471 fi->fib_scope = cfg->fc_scope;
1472 fi->fib_flags = cfg->fc_flags;
1473 fi->fib_priority = cfg->fc_priority;
1474 fi->fib_prefsrc = cfg->fc_prefsrc;
1475 fi->fib_type = cfg->fc_type;
1476 fi->fib_tb_id = cfg->fc_table;
1477
1478 fi->fib_nhs = nhs;
1479 if (nh) {
1480 if (!nexthop_get(nh)) {
1481 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1482 err = -EINVAL;
1483 } else {
1484 err = 0;
1485 fi->nh = nh;
1486 }
1487 } else {
1488 change_nexthops(fi) {
1489 nexthop_nh->nh_parent = fi;
1490 } endfor_nexthops(fi)
1491
1492 if (cfg->fc_mp)
1493 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1494 extack);
1495 else
1496 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1497 }
1498
1499 if (err != 0)
1500 goto failure;
1501
1502 if (fib_props[cfg->fc_type].error) {
1503 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1504 NL_SET_ERR_MSG(extack,
1505 "Gateway, device and multipath can not be specified for this route type");
1506 goto err_inval;
1507 }
1508 goto link_it;
1509 } else {
1510 switch (cfg->fc_type) {
1511 case RTN_UNICAST:
1512 case RTN_LOCAL:
1513 case RTN_BROADCAST:
1514 case RTN_ANYCAST:
1515 case RTN_MULTICAST:
1516 break;
1517 default:
1518 NL_SET_ERR_MSG(extack, "Invalid route type");
1519 goto err_inval;
1520 }
1521 }
1522
1523 if (cfg->fc_scope > RT_SCOPE_HOST) {
1524 NL_SET_ERR_MSG(extack, "Invalid scope");
1525 goto err_inval;
1526 }
1527
1528 if (fi->nh) {
1529 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1530 if (err)
1531 goto failure;
1532 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1533 struct fib_nh *nh = fi->fib_nh;
1534
1535 /* Local address is added. */
1536 if (nhs != 1) {
1537 NL_SET_ERR_MSG(extack,
1538 "Route with host scope can not have multiple nexthops");
1539 goto err_inval;
1540 }
1541 if (nh->fib_nh_gw_family) {
1542 NL_SET_ERR_MSG(extack,
1543 "Route with host scope can not have a gateway");
1544 goto err_inval;
1545 }
1546 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1547 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1548 err = -ENODEV;
1549 if (!nh->fib_nh_dev)
1550 goto failure;
1551 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1552 GFP_KERNEL);
1553 } else {
1554 int linkdown = 0;
1555
1556 change_nexthops(fi) {
1557 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1558 cfg->fc_table, cfg->fc_scope,
1559 extack);
1560 if (err != 0)
1561 goto failure;
1562 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1563 linkdown++;
1564 } endfor_nexthops(fi)
1565 if (linkdown == fi->fib_nhs)
1566 fi->fib_flags |= RTNH_F_LINKDOWN;
1567 }
1568
1569 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1570 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1571 goto err_inval;
1572 }
1573
1574 if (!fi->nh) {
1575 change_nexthops(fi) {
1576 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1577 fi->fib_scope);
1578 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1579 fi->fib_nh_is_v6 = true;
1580 } endfor_nexthops(fi)
1581
1582 fib_rebalance(fi);
1583 }
1584
1585 link_it:
1586 ofi = fib_find_info(fi);
1587 if (ofi) {
1588 /* fib_table_lookup() should not see @fi yet. */
1589 fi->fib_dead = 1;
1590 free_fib_info(fi);
1591 refcount_inc(&ofi->fib_treeref);
1592 return ofi;
1593 }
1594
1595 refcount_set(&fi->fib_treeref, 1);
1596 refcount_set(&fi->fib_clntref, 1);
1597 spin_lock_bh(&fib_info_lock);
1598 fib_info_cnt++;
1599 hlist_add_head(&fi->fib_hash,
1600 &fib_info_hash[fib_info_hashfn(fi)]);
1601 if (fi->fib_prefsrc) {
1602 struct hlist_head *head;
1603
1604 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc);
1605 hlist_add_head(&fi->fib_lhash, head);
1606 }
1607 if (fi->nh) {
1608 list_add(&fi->nh_list, &nh->fi_list);
1609 } else {
1610 change_nexthops(fi) {
1611 struct hlist_head *head;
1612
1613 if (!nexthop_nh->fib_nh_dev)
1614 continue;
1615 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
1616 hlist_add_head(&nexthop_nh->nh_hash, head);
1617 } endfor_nexthops(fi)
1618 }
1619 spin_unlock_bh(&fib_info_lock);
1620 return fi;
1621
1622 err_inval:
1623 err = -EINVAL;
1624
1625 failure:
1626 if (fi) {
1627 /* fib_table_lookup() should not see @fi yet. */
1628 fi->fib_dead = 1;
1629 free_fib_info(fi);
1630 }
1631
1632 return ERR_PTR(err);
1633 }
1634
1635 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1636 u8 rt_family, unsigned char *flags, bool skip_oif)
1637 {
1638 if (nhc->nhc_flags & RTNH_F_DEAD)
1639 *flags |= RTNH_F_DEAD;
1640
1641 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1642 *flags |= RTNH_F_LINKDOWN;
1643
1644 rcu_read_lock();
1645 switch (nhc->nhc_family) {
1646 case AF_INET:
1647 if (ip_ignore_linkdown(nhc->nhc_dev))
1648 *flags |= RTNH_F_DEAD;
1649 break;
1650 case AF_INET6:
1651 if (ip6_ignore_linkdown(nhc->nhc_dev))
1652 *flags |= RTNH_F_DEAD;
1653 break;
1654 }
1655 rcu_read_unlock();
1656 }
1657
1658 switch (nhc->nhc_gw_family) {
1659 case AF_INET:
1660 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1661 goto nla_put_failure;
1662 break;
1663 case AF_INET6:
1664 /* if gateway family does not match nexthop family
1665 * gateway is encoded as RTA_VIA
1666 */
1667 if (rt_family != nhc->nhc_gw_family) {
1668 int alen = sizeof(struct in6_addr);
1669 struct nlattr *nla;
1670 struct rtvia *via;
1671
1672 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1673 if (!nla)
1674 goto nla_put_failure;
1675
1676 via = nla_data(nla);
1677 via->rtvia_family = AF_INET6;
1678 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1679 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1680 &nhc->nhc_gw.ipv6) < 0) {
1681 goto nla_put_failure;
1682 }
1683 break;
1684 }
1685
1686 *flags |= (nhc->nhc_flags &
1687 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1688
1689 if (!skip_oif && nhc->nhc_dev &&
1690 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1691 goto nla_put_failure;
1692
1693 if (nhc->nhc_lwtstate &&
1694 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1695 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1696 goto nla_put_failure;
1697
1698 return 0;
1699
1700 nla_put_failure:
1701 return -EMSGSIZE;
1702 }
1703 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1704
1705 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1706 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1707 int nh_weight, u8 rt_family, u32 nh_tclassid)
1708 {
1709 const struct net_device *dev = nhc->nhc_dev;
1710 struct rtnexthop *rtnh;
1711 unsigned char flags = 0;
1712
1713 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1714 if (!rtnh)
1715 goto nla_put_failure;
1716
1717 rtnh->rtnh_hops = nh_weight - 1;
1718 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1719
1720 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1721 goto nla_put_failure;
1722
1723 rtnh->rtnh_flags = flags;
1724
1725 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1726 goto nla_put_failure;
1727
1728 /* length of rtnetlink header + attributes */
1729 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1730
1731 return 0;
1732
1733 nla_put_failure:
1734 return -EMSGSIZE;
1735 }
1736 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1737 #endif
1738
1739 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1740 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1741 {
1742 struct nlattr *mp;
1743
1744 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1745 if (!mp)
1746 goto nla_put_failure;
1747
1748 if (unlikely(fi->nh)) {
1749 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1750 goto nla_put_failure;
1751 goto mp_end;
1752 }
1753
1754 for_nexthops(fi) {
1755 u32 nh_tclassid = 0;
1756 #ifdef CONFIG_IP_ROUTE_CLASSID
1757 nh_tclassid = nh->nh_tclassid;
1758 #endif
1759 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1760 AF_INET, nh_tclassid) < 0)
1761 goto nla_put_failure;
1762 } endfor_nexthops(fi);
1763
1764 mp_end:
1765 nla_nest_end(skb, mp);
1766
1767 return 0;
1768
1769 nla_put_failure:
1770 return -EMSGSIZE;
1771 }
1772 #else
1773 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1774 {
1775 return 0;
1776 }
1777 #endif
1778
1779 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1780 const struct fib_rt_info *fri, unsigned int flags)
1781 {
1782 unsigned int nhs = fib_info_num_path(fri->fi);
1783 struct fib_info *fi = fri->fi;
1784 u32 tb_id = fri->tb_id;
1785 struct nlmsghdr *nlh;
1786 struct rtmsg *rtm;
1787
1788 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1789 if (!nlh)
1790 return -EMSGSIZE;
1791
1792 rtm = nlmsg_data(nlh);
1793 rtm->rtm_family = AF_INET;
1794 rtm->rtm_dst_len = fri->dst_len;
1795 rtm->rtm_src_len = 0;
1796 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp);
1797 if (tb_id < 256)
1798 rtm->rtm_table = tb_id;
1799 else
1800 rtm->rtm_table = RT_TABLE_COMPAT;
1801 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1802 goto nla_put_failure;
1803 rtm->rtm_type = fri->type;
1804 rtm->rtm_flags = fi->fib_flags;
1805 rtm->rtm_scope = fi->fib_scope;
1806 rtm->rtm_protocol = fi->fib_protocol;
1807
1808 if (rtm->rtm_dst_len &&
1809 nla_put_in_addr(skb, RTA_DST, fri->dst))
1810 goto nla_put_failure;
1811 if (fi->fib_priority &&
1812 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1813 goto nla_put_failure;
1814 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1815 goto nla_put_failure;
1816
1817 if (fi->fib_prefsrc &&
1818 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1819 goto nla_put_failure;
1820
1821 if (fi->nh) {
1822 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1823 goto nla_put_failure;
1824 if (nexthop_is_blackhole(fi->nh))
1825 rtm->rtm_type = RTN_BLACKHOLE;
1826 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
1827 goto offload;
1828 }
1829
1830 if (nhs == 1) {
1831 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1832 unsigned char flags = 0;
1833
1834 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1835 goto nla_put_failure;
1836
1837 rtm->rtm_flags = flags;
1838 #ifdef CONFIG_IP_ROUTE_CLASSID
1839 if (nhc->nhc_family == AF_INET) {
1840 struct fib_nh *nh;
1841
1842 nh = container_of(nhc, struct fib_nh, nh_common);
1843 if (nh->nh_tclassid &&
1844 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1845 goto nla_put_failure;
1846 }
1847 #endif
1848 } else {
1849 if (fib_add_multipath(skb, fi) < 0)
1850 goto nla_put_failure;
1851 }
1852
1853 offload:
1854 if (fri->offload)
1855 rtm->rtm_flags |= RTM_F_OFFLOAD;
1856 if (fri->trap)
1857 rtm->rtm_flags |= RTM_F_TRAP;
1858 if (fri->offload_failed)
1859 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1860
1861 nlmsg_end(skb, nlh);
1862 return 0;
1863
1864 nla_put_failure:
1865 nlmsg_cancel(skb, nlh);
1866 return -EMSGSIZE;
1867 }
1868
1869 /*
1870 * Update FIB if:
1871 * - local address disappeared -> we must delete all the entries
1872 * referring to it.
1873 * - device went down -> we must shutdown all nexthops going via it.
1874 */
1875 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1876 {
1877 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1878 struct net *net = dev_net(dev);
1879 struct hlist_head *head;
1880 struct fib_info *fi;
1881 int ret = 0;
1882
1883 if (!fib_info_laddrhash || local == 0)
1884 return 0;
1885
1886 head = fib_info_laddrhash_bucket(net, local);
1887 hlist_for_each_entry(fi, head, fib_lhash) {
1888 if (!net_eq(fi->fib_net, net) ||
1889 fi->fib_tb_id != tb_id)
1890 continue;
1891 if (fi->fib_prefsrc == local) {
1892 fi->fib_flags |= RTNH_F_DEAD;
1893 fi->pfsrc_removed = true;
1894 ret++;
1895 }
1896 }
1897 return ret;
1898 }
1899
1900 static int call_fib_nh_notifiers(struct fib_nh *nh,
1901 enum fib_event_type event_type)
1902 {
1903 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1904 struct fib_nh_notifier_info info = {
1905 .fib_nh = nh,
1906 };
1907
1908 switch (event_type) {
1909 case FIB_EVENT_NH_ADD:
1910 if (nh->fib_nh_flags & RTNH_F_DEAD)
1911 break;
1912 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1913 break;
1914 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1915 &info.info);
1916 case FIB_EVENT_NH_DEL:
1917 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1918 (nh->fib_nh_flags & RTNH_F_DEAD))
1919 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1920 event_type, &info.info);
1921 break;
1922 default:
1923 break;
1924 }
1925
1926 return NOTIFY_DONE;
1927 }
1928
1929 /* Update the PMTU of exceptions when:
1930 * - the new MTU of the first hop becomes smaller than the PMTU
1931 * - the old MTU was the same as the PMTU, and it limited discovery of
1932 * larger MTUs on the path. With that limit raised, we can now
1933 * discover larger MTUs
1934 * A special case is locked exceptions, for which the PMTU is smaller
1935 * than the minimal accepted PMTU:
1936 * - if the new MTU is greater than the PMTU, don't make any change
1937 * - otherwise, unlock and set PMTU
1938 */
1939 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1940 {
1941 struct fnhe_hash_bucket *bucket;
1942 int i;
1943
1944 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1945 if (!bucket)
1946 return;
1947
1948 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1949 struct fib_nh_exception *fnhe;
1950
1951 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1952 fnhe;
1953 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1954 if (fnhe->fnhe_mtu_locked) {
1955 if (new <= fnhe->fnhe_pmtu) {
1956 fnhe->fnhe_pmtu = new;
1957 fnhe->fnhe_mtu_locked = false;
1958 }
1959 } else if (new < fnhe->fnhe_pmtu ||
1960 orig == fnhe->fnhe_pmtu) {
1961 fnhe->fnhe_pmtu = new;
1962 }
1963 }
1964 }
1965 }
1966
1967 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1968 {
1969 struct hlist_head *head = fib_info_devhash_bucket(dev);
1970 struct fib_nh *nh;
1971
1972 hlist_for_each_entry(nh, head, nh_hash) {
1973 if (nh->fib_nh_dev == dev)
1974 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1975 }
1976 }
1977
1978 /* Event force Flags Description
1979 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1980 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1981 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1982 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1983 *
1984 * only used when fib_nh is built into fib_info
1985 */
1986 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1987 {
1988 struct hlist_head *head = fib_info_devhash_bucket(dev);
1989 struct fib_info *prev_fi = NULL;
1990 int scope = RT_SCOPE_NOWHERE;
1991 struct fib_nh *nh;
1992 int ret = 0;
1993
1994 if (force)
1995 scope = -1;
1996
1997 hlist_for_each_entry(nh, head, nh_hash) {
1998 struct fib_info *fi = nh->nh_parent;
1999 int dead;
2000
2001 BUG_ON(!fi->fib_nhs);
2002 if (nh->fib_nh_dev != dev || fi == prev_fi)
2003 continue;
2004 prev_fi = fi;
2005 dead = 0;
2006 change_nexthops(fi) {
2007 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
2008 dead++;
2009 else if (nexthop_nh->fib_nh_dev == dev &&
2010 nexthop_nh->fib_nh_scope != scope) {
2011 switch (event) {
2012 case NETDEV_DOWN:
2013 case NETDEV_UNREGISTER:
2014 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
2015 fallthrough;
2016 case NETDEV_CHANGE:
2017 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
2018 break;
2019 }
2020 call_fib_nh_notifiers(nexthop_nh,
2021 FIB_EVENT_NH_DEL);
2022 dead++;
2023 }
2024 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2025 if (event == NETDEV_UNREGISTER &&
2026 nexthop_nh->fib_nh_dev == dev) {
2027 dead = fi->fib_nhs;
2028 break;
2029 }
2030 #endif
2031 } endfor_nexthops(fi)
2032 if (dead == fi->fib_nhs) {
2033 switch (event) {
2034 case NETDEV_DOWN:
2035 case NETDEV_UNREGISTER:
2036 fi->fib_flags |= RTNH_F_DEAD;
2037 fallthrough;
2038 case NETDEV_CHANGE:
2039 fi->fib_flags |= RTNH_F_LINKDOWN;
2040 break;
2041 }
2042 ret++;
2043 }
2044
2045 fib_rebalance(fi);
2046 }
2047
2048 return ret;
2049 }
2050
2051 /* Must be invoked inside of an RCU protected region. */
2052 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2053 {
2054 struct fib_info *fi = NULL, *last_resort = NULL;
2055 struct hlist_head *fa_head = res->fa_head;
2056 struct fib_table *tb = res->table;
2057 u8 slen = 32 - res->prefixlen;
2058 int order = -1, last_idx = -1;
2059 struct fib_alias *fa, *fa1 = NULL;
2060 u32 last_prio = res->fi->fib_priority;
2061 dscp_t last_dscp = 0;
2062
2063 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2064 struct fib_info *next_fi = fa->fa_info;
2065 struct fib_nh_common *nhc;
2066
2067 if (fa->fa_slen != slen)
2068 continue;
2069 if (fa->fa_dscp &&
2070 fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos))
2071 continue;
2072 if (fa->tb_id != tb->tb_id)
2073 continue;
2074 if (next_fi->fib_priority > last_prio &&
2075 fa->fa_dscp == last_dscp) {
2076 if (last_dscp)
2077 continue;
2078 break;
2079 }
2080 if (next_fi->fib_flags & RTNH_F_DEAD)
2081 continue;
2082 last_dscp = fa->fa_dscp;
2083 last_prio = next_fi->fib_priority;
2084
2085 if (next_fi->fib_scope != res->scope ||
2086 fa->fa_type != RTN_UNICAST)
2087 continue;
2088
2089 nhc = fib_info_nhc(next_fi, 0);
2090 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2091 continue;
2092
2093 fib_alias_accessed(fa);
2094
2095 if (!fi) {
2096 if (next_fi != res->fi)
2097 break;
2098 fa1 = fa;
2099 } else if (!fib_detect_death(fi, order, &last_resort,
2100 &last_idx, fa1->fa_default)) {
2101 fib_result_assign(res, fi);
2102 fa1->fa_default = order;
2103 goto out;
2104 }
2105 fi = next_fi;
2106 order++;
2107 }
2108
2109 if (order <= 0 || !fi) {
2110 if (fa1)
2111 fa1->fa_default = -1;
2112 goto out;
2113 }
2114
2115 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2116 fa1->fa_default)) {
2117 fib_result_assign(res, fi);
2118 fa1->fa_default = order;
2119 goto out;
2120 }
2121
2122 if (last_idx >= 0)
2123 fib_result_assign(res, last_resort);
2124 fa1->fa_default = last_idx;
2125 out:
2126 return;
2127 }
2128
2129 /*
2130 * Dead device goes up. We wake up dead nexthops.
2131 * It takes sense only on multipath routes.
2132 *
2133 * only used when fib_nh is built into fib_info
2134 */
2135 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2136 {
2137 struct fib_info *prev_fi;
2138 struct hlist_head *head;
2139 struct fib_nh *nh;
2140 int ret;
2141
2142 if (!(dev->flags & IFF_UP))
2143 return 0;
2144
2145 if (nh_flags & RTNH_F_DEAD) {
2146 unsigned int flags = dev_get_flags(dev);
2147
2148 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2149 nh_flags |= RTNH_F_LINKDOWN;
2150 }
2151
2152 prev_fi = NULL;
2153 head = fib_info_devhash_bucket(dev);
2154 ret = 0;
2155
2156 hlist_for_each_entry(nh, head, nh_hash) {
2157 struct fib_info *fi = nh->nh_parent;
2158 int alive;
2159
2160 BUG_ON(!fi->fib_nhs);
2161 if (nh->fib_nh_dev != dev || fi == prev_fi)
2162 continue;
2163
2164 prev_fi = fi;
2165 alive = 0;
2166 change_nexthops(fi) {
2167 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2168 alive++;
2169 continue;
2170 }
2171 if (!nexthop_nh->fib_nh_dev ||
2172 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2173 continue;
2174 if (nexthop_nh->fib_nh_dev != dev ||
2175 !__in_dev_get_rtnl(dev))
2176 continue;
2177 alive++;
2178 nexthop_nh->fib_nh_flags &= ~nh_flags;
2179 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2180 } endfor_nexthops(fi)
2181
2182 if (alive > 0) {
2183 fi->fib_flags &= ~nh_flags;
2184 ret++;
2185 }
2186
2187 fib_rebalance(fi);
2188 }
2189
2190 return ret;
2191 }
2192
2193 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2194 static bool fib_good_nh(const struct fib_nh *nh)
2195 {
2196 int state = NUD_REACHABLE;
2197
2198 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2199 struct neighbour *n;
2200
2201 rcu_read_lock();
2202
2203 if (likely(nh->fib_nh_gw_family == AF_INET))
2204 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2205 (__force u32)nh->fib_nh_gw4);
2206 else if (nh->fib_nh_gw_family == AF_INET6)
2207 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2208 &nh->fib_nh_gw6);
2209 else
2210 n = NULL;
2211 if (n)
2212 state = READ_ONCE(n->nud_state);
2213
2214 rcu_read_unlock();
2215 }
2216
2217 return !!(state & NUD_VALID);
2218 }
2219
2220 void fib_select_multipath(struct fib_result *res, int hash)
2221 {
2222 struct fib_info *fi = res->fi;
2223 struct net *net = fi->fib_net;
2224 bool first = false;
2225
2226 if (unlikely(res->fi->nh)) {
2227 nexthop_path_fib_result(res, hash);
2228 return;
2229 }
2230
2231 change_nexthops(fi) {
2232 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) {
2233 if (!fib_good_nh(nexthop_nh))
2234 continue;
2235 if (!first) {
2236 res->nh_sel = nhsel;
2237 res->nhc = &nexthop_nh->nh_common;
2238 first = true;
2239 }
2240 }
2241
2242 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2243 continue;
2244
2245 res->nh_sel = nhsel;
2246 res->nhc = &nexthop_nh->nh_common;
2247 return;
2248 } endfor_nexthops(fi);
2249 }
2250 #endif
2251
2252 void fib_select_path(struct net *net, struct fib_result *res,
2253 struct flowi4 *fl4, const struct sk_buff *skb)
2254 {
2255 if (fl4->flowi4_oif)
2256 goto check_saddr;
2257
2258 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2259 if (fib_info_num_path(res->fi) > 1) {
2260 int h = fib_multipath_hash(net, fl4, skb, NULL);
2261
2262 fib_select_multipath(res, h);
2263 }
2264 else
2265 #endif
2266 if (!res->prefixlen &&
2267 res->table->tb_num_default > 1 &&
2268 res->type == RTN_UNICAST)
2269 fib_select_default(fl4, res);
2270
2271 check_saddr:
2272 if (!fl4->saddr) {
2273 struct net_device *l3mdev;
2274
2275 l3mdev = dev_get_by_index_rcu(net, fl4->flowi4_l3mdev);
2276
2277 if (!l3mdev ||
2278 l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) == l3mdev)
2279 fl4->saddr = fib_result_prefsrc(net, res);
2280 else
2281 fl4->saddr = inet_select_addr(l3mdev, 0, RT_SCOPE_LINK);
2282 }
2283 }
2284
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