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/ip.h>
37 #include <net/protocol.h>
38 #include <net/route.h>
39 #include <net/tcp.h>
40 #include <net/sock.h>
41 #include <net/ip_fib.h>
42 #include <net/ip6_fib.h>
43 #include <net/nexthop.h>
44 #include <net/netlink.h>
45 #include <net/rtnh.h>
46 #include <net/lwtunnel.h>
47 #include <net/fib_notifier.h>
48 #include <net/addrconf.h>
49
50 #include "fib_lookup.h"
51
52 static DEFINE_SPINLOCK(fib_info_lock);
53 static struct hlist_head *fib_info_hash;
54 static struct hlist_head *fib_info_laddrhash;
55 static unsigned int fib_info_hash_size;
56 static unsigned int fib_info_cnt;
57
58 #define DEVINDEX_HASHBITS 8
59 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
60 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
61
62 /* for_nexthops and change_nexthops only used when nexthop object
63 * is not set in a fib_info. The logic within can reference fib_nh.
64 */
65 #ifdef CONFIG_IP_ROUTE_MULTIPATH
66
67 #define for_nexthops(fi) { \
68 int nhsel; const struct fib_nh *nh; \
69 for (nhsel = 0, nh = (fi)->fib_nh; \
70 nhsel < fib_info_num_path((fi)); \
71 nh++, nhsel++)
72
73 #define change_nexthops(fi) { \
74 int nhsel; struct fib_nh *nexthop_nh; \
75 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
76 nhsel < fib_info_num_path((fi)); \
77 nexthop_nh++, nhsel++)
78
79 #else /* CONFIG_IP_ROUTE_MULTIPATH */
80
81 /* Hope, that gcc will optimize it to get rid of dummy loop */
82
83 #define for_nexthops(fi) { \
84 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87 #define change_nexthops(fi) { \
88 int nhsel; \
89 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
90 for (nhsel = 0; nhsel < 1; nhsel++)
91
92 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
93
94 #define endfor_nexthops(fi) }
95
96
97 const struct fib_prop fib_props[RTN_MAX + 1] = {
98 [RTN_UNSPEC] = {
99 .error = 0,
100 .scope = RT_SCOPE_NOWHERE,
101 },
102 [RTN_UNICAST] = {
103 .error = 0,
104 .scope = RT_SCOPE_UNIVERSE,
105 },
106 [RTN_LOCAL] = {
107 .error = 0,
108 .scope = RT_SCOPE_HOST,
109 },
110 [RTN_BROADCAST] = {
111 .error = 0,
112 .scope = RT_SCOPE_LINK,
113 },
114 [RTN_ANYCAST] = {
115 .error = 0,
116 .scope = RT_SCOPE_LINK,
117 },
118 [RTN_MULTICAST] = {
119 .error = 0,
120 .scope = RT_SCOPE_UNIVERSE,
121 },
122 [RTN_BLACKHOLE] = {
123 .error = -EINVAL,
124 .scope = RT_SCOPE_UNIVERSE,
125 },
126 [RTN_UNREACHABLE] = {
127 .error = -EHOSTUNREACH,
128 .scope = RT_SCOPE_UNIVERSE,
129 },
130 [RTN_PROHIBIT] = {
131 .error = -EACCES,
132 .scope = RT_SCOPE_UNIVERSE,
133 },
134 [RTN_THROW] = {
135 .error = -EAGAIN,
136 .scope = RT_SCOPE_UNIVERSE,
137 },
138 [RTN_NAT] = {
139 .error = -EINVAL,
140 .scope = RT_SCOPE_NOWHERE,
141 },
142 [RTN_XRESOLVE] = {
143 .error = -EINVAL,
144 .scope = RT_SCOPE_NOWHERE,
145 },
146 };
147
rt_fibinfo_free(struct rtable __rcu ** rtp)148 static void rt_fibinfo_free(struct rtable __rcu **rtp)
149 {
150 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
151
152 if (!rt)
153 return;
154
155 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
156 * because we waited an RCU grace period before calling
157 * free_fib_info_rcu()
158 */
159
160 dst_dev_put(&rt->dst);
161 dst_release_immediate(&rt->dst);
162 }
163
free_nh_exceptions(struct fib_nh_common * nhc)164 static void free_nh_exceptions(struct fib_nh_common *nhc)
165 {
166 struct fnhe_hash_bucket *hash;
167 int i;
168
169 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
170 if (!hash)
171 return;
172 for (i = 0; i < FNHE_HASH_SIZE; i++) {
173 struct fib_nh_exception *fnhe;
174
175 fnhe = rcu_dereference_protected(hash[i].chain, 1);
176 while (fnhe) {
177 struct fib_nh_exception *next;
178
179 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
180
181 rt_fibinfo_free(&fnhe->fnhe_rth_input);
182 rt_fibinfo_free(&fnhe->fnhe_rth_output);
183
184 kfree(fnhe);
185
186 fnhe = next;
187 }
188 }
189 kfree(hash);
190 }
191
rt_fibinfo_free_cpus(struct rtable __rcu * __percpu * rtp)192 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
193 {
194 int cpu;
195
196 if (!rtp)
197 return;
198
199 for_each_possible_cpu(cpu) {
200 struct rtable *rt;
201
202 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
203 if (rt) {
204 dst_dev_put(&rt->dst);
205 dst_release_immediate(&rt->dst);
206 }
207 }
208 free_percpu(rtp);
209 }
210
fib_nh_common_release(struct fib_nh_common * nhc)211 void fib_nh_common_release(struct fib_nh_common *nhc)
212 {
213 if (nhc->nhc_dev)
214 dev_put(nhc->nhc_dev);
215
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
fib_nh_release(struct net * net,struct fib_nh * fib_nh)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 */
free_fib_info_rcu(struct rcu_head * head)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
free_fib_info(struct fib_info * fi)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 fib_info_cnt--;
257
258 call_rcu(&fi->rcu, free_fib_info_rcu);
259 }
260 EXPORT_SYMBOL_GPL(free_fib_info);
261
fib_release_info(struct fib_info * fi)262 void fib_release_info(struct fib_info *fi)
263 {
264 spin_lock_bh(&fib_info_lock);
265 if (fi && --fi->fib_treeref == 0) {
266 hlist_del(&fi->fib_hash);
267 if (fi->fib_prefsrc)
268 hlist_del(&fi->fib_lhash);
269 if (fi->nh) {
270 list_del(&fi->nh_list);
271 } else {
272 change_nexthops(fi) {
273 if (!nexthop_nh->fib_nh_dev)
274 continue;
275 hlist_del(&nexthop_nh->nh_hash);
276 } endfor_nexthops(fi)
277 }
278 /* Paired with READ_ONCE() from fib_table_lookup() */
279 WRITE_ONCE(fi->fib_dead, 1);
280 fib_info_put(fi);
281 }
282 spin_unlock_bh(&fib_info_lock);
283 }
284
nh_comp(struct fib_info * fi,struct fib_info * ofi)285 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
286 {
287 const struct fib_nh *onh;
288
289 if (fi->nh || ofi->nh)
290 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
291
292 if (ofi->fib_nhs == 0)
293 return 0;
294
295 for_nexthops(fi) {
296 onh = fib_info_nh(ofi, nhsel);
297
298 if (nh->fib_nh_oif != onh->fib_nh_oif ||
299 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
300 nh->fib_nh_scope != onh->fib_nh_scope ||
301 #ifdef CONFIG_IP_ROUTE_MULTIPATH
302 nh->fib_nh_weight != onh->fib_nh_weight ||
303 #endif
304 #ifdef CONFIG_IP_ROUTE_CLASSID
305 nh->nh_tclassid != onh->nh_tclassid ||
306 #endif
307 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
308 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
309 return -1;
310
311 if (nh->fib_nh_gw_family == AF_INET &&
312 nh->fib_nh_gw4 != onh->fib_nh_gw4)
313 return -1;
314
315 if (nh->fib_nh_gw_family == AF_INET6 &&
316 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
317 return -1;
318 } endfor_nexthops(fi);
319 return 0;
320 }
321
fib_devindex_hashfn(unsigned int val)322 static inline unsigned int fib_devindex_hashfn(unsigned int val)
323 {
324 return hash_32(val, DEVINDEX_HASHBITS);
325 }
326
327 static struct hlist_head *
fib_info_devhash_bucket(const struct net_device * dev)328 fib_info_devhash_bucket(const struct net_device *dev)
329 {
330 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
331
332 return &fib_info_devhash[fib_devindex_hashfn(val)];
333 }
334
fib_info_hashfn_1(int init_val,u8 protocol,u8 scope,u32 prefsrc,u32 priority)335 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
336 u32 prefsrc, u32 priority)
337 {
338 unsigned int val = init_val;
339
340 val ^= (protocol << 8) | scope;
341 val ^= prefsrc;
342 val ^= priority;
343
344 return val;
345 }
346
fib_info_hashfn_result(unsigned int val)347 static unsigned int fib_info_hashfn_result(unsigned int val)
348 {
349 unsigned int mask = (fib_info_hash_size - 1);
350
351 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
352 }
353
fib_info_hashfn(struct fib_info * fi)354 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
355 {
356 unsigned int val;
357
358 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
359 fi->fib_scope, (__force u32)fi->fib_prefsrc,
360 fi->fib_priority);
361
362 if (fi->nh) {
363 val ^= fib_devindex_hashfn(fi->nh->id);
364 } else {
365 for_nexthops(fi) {
366 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
367 } endfor_nexthops(fi)
368 }
369
370 return fib_info_hashfn_result(val);
371 }
372
373 /* no metrics, only nexthop id */
fib_find_info_nh(struct net * net,const struct fib_config * cfg)374 static struct fib_info *fib_find_info_nh(struct net *net,
375 const struct fib_config *cfg)
376 {
377 struct hlist_head *head;
378 struct fib_info *fi;
379 unsigned int hash;
380
381 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
382 cfg->fc_protocol, cfg->fc_scope,
383 (__force u32)cfg->fc_prefsrc,
384 cfg->fc_priority);
385 hash = fib_info_hashfn_result(hash);
386 head = &fib_info_hash[hash];
387
388 hlist_for_each_entry(fi, head, fib_hash) {
389 if (!net_eq(fi->fib_net, net))
390 continue;
391 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
392 continue;
393 if (cfg->fc_protocol == fi->fib_protocol &&
394 cfg->fc_scope == fi->fib_scope &&
395 cfg->fc_prefsrc == fi->fib_prefsrc &&
396 cfg->fc_priority == fi->fib_priority &&
397 cfg->fc_type == fi->fib_type &&
398 cfg->fc_table == fi->fib_tb_id &&
399 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
400 return fi;
401 }
402
403 return NULL;
404 }
405
fib_find_info(struct fib_info * nfi)406 static struct fib_info *fib_find_info(struct fib_info *nfi)
407 {
408 struct hlist_head *head;
409 struct fib_info *fi;
410 unsigned int hash;
411
412 hash = fib_info_hashfn(nfi);
413 head = &fib_info_hash[hash];
414
415 hlist_for_each_entry(fi, head, fib_hash) {
416 if (!net_eq(fi->fib_net, nfi->fib_net))
417 continue;
418 if (fi->fib_nhs != nfi->fib_nhs)
419 continue;
420 if (nfi->fib_protocol == fi->fib_protocol &&
421 nfi->fib_scope == fi->fib_scope &&
422 nfi->fib_prefsrc == fi->fib_prefsrc &&
423 nfi->fib_priority == fi->fib_priority &&
424 nfi->fib_type == fi->fib_type &&
425 nfi->fib_tb_id == fi->fib_tb_id &&
426 memcmp(nfi->fib_metrics, fi->fib_metrics,
427 sizeof(u32) * RTAX_MAX) == 0 &&
428 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
429 nh_comp(fi, nfi) == 0)
430 return fi;
431 }
432
433 return NULL;
434 }
435
436 /* Check, that the gateway is already configured.
437 * Used only by redirect accept routine.
438 */
ip_fib_check_default(__be32 gw,struct net_device * dev)439 int ip_fib_check_default(__be32 gw, struct net_device *dev)
440 {
441 struct hlist_head *head;
442 struct fib_nh *nh;
443
444 spin_lock(&fib_info_lock);
445
446 head = fib_info_devhash_bucket(dev);
447
448 hlist_for_each_entry(nh, head, nh_hash) {
449 if (nh->fib_nh_dev == dev &&
450 nh->fib_nh_gw4 == gw &&
451 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
452 spin_unlock(&fib_info_lock);
453 return 0;
454 }
455 }
456
457 spin_unlock(&fib_info_lock);
458
459 return -1;
460 }
461
fib_nlmsg_size(struct fib_info * fi)462 static inline size_t fib_nlmsg_size(struct fib_info *fi)
463 {
464 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
465 + nla_total_size(4) /* RTA_TABLE */
466 + nla_total_size(4) /* RTA_DST */
467 + nla_total_size(4) /* RTA_PRIORITY */
468 + nla_total_size(4) /* RTA_PREFSRC */
469 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
470 unsigned int nhs = fib_info_num_path(fi);
471
472 /* space for nested metrics */
473 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
474
475 if (fi->nh)
476 payload += nla_total_size(4); /* RTA_NH_ID */
477
478 if (nhs) {
479 size_t nh_encapsize = 0;
480 /* Also handles the special case nhs == 1 */
481
482 /* each nexthop is packed in an attribute */
483 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
484 unsigned int i;
485
486 /* may contain flow and gateway attribute */
487 nhsize += 2 * nla_total_size(4);
488
489 /* grab encap info */
490 for (i = 0; i < fib_info_num_path(fi); i++) {
491 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
492
493 if (nhc->nhc_lwtstate) {
494 /* RTA_ENCAP_TYPE */
495 nh_encapsize += lwtunnel_get_encap_size(
496 nhc->nhc_lwtstate);
497 /* RTA_ENCAP */
498 nh_encapsize += nla_total_size(2);
499 }
500 }
501
502 /* all nexthops are packed in a nested attribute */
503 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
504
505 }
506
507 return payload;
508 }
509
rtmsg_fib(int event,__be32 key,struct fib_alias * fa,int dst_len,u32 tb_id,const struct nl_info * info,unsigned int nlm_flags)510 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
511 int dst_len, u32 tb_id, const struct nl_info *info,
512 unsigned int nlm_flags)
513 {
514 struct sk_buff *skb;
515 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
516 int err = -ENOBUFS;
517
518 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
519 if (!skb)
520 goto errout;
521
522 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
523 fa->fa_type, key, dst_len,
524 fa->fa_tos, fa->fa_info, 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
fib_detect_death(struct fib_info * fi,int order,struct fib_info ** last_resort,int * last_idx,int dflt)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
fib_nh_common_init(struct fib_nh_common * nhc,struct nlattr * encap,u16 encap_type,void * cfg,gfp_t gfp_flags,struct netlink_ext_ack * extack)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
fib_nh_init(struct net * net,struct fib_nh * nh,struct fib_config * cfg,int nh_weight,struct netlink_ext_ack * extack)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 atomic_inc(&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
fib_count_nexthops(struct rtnexthop * rtnh,int remaining,struct netlink_ext_ack * extack)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
fib_gw_from_attr(__be32 * gw,struct nlattr * nla,struct netlink_ext_ack * extack)664 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
665 struct netlink_ext_ack *extack)
666 {
667 if (nla_len(nla) < sizeof(*gw)) {
668 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
669 return -EINVAL;
670 }
671
672 *gw = nla_get_in_addr(nla);
673
674 return 0;
675 }
676
677 /* only called when fib_nh is integrated into fib_info */
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)678 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
679 int remaining, struct fib_config *cfg,
680 struct netlink_ext_ack *extack)
681 {
682 struct net *net = fi->fib_net;
683 struct fib_config fib_cfg;
684 struct fib_nh *nh;
685 int ret;
686
687 change_nexthops(fi) {
688 int attrlen;
689
690 memset(&fib_cfg, 0, sizeof(fib_cfg));
691
692 if (!rtnh_ok(rtnh, remaining)) {
693 NL_SET_ERR_MSG(extack,
694 "Invalid nexthop configuration - extra data after nexthop");
695 return -EINVAL;
696 }
697
698 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
699 NL_SET_ERR_MSG(extack,
700 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
701 return -EINVAL;
702 }
703
704 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
705 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
706
707 attrlen = rtnh_attrlen(rtnh);
708 if (attrlen > 0) {
709 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
710
711 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
712 nlav = nla_find(attrs, attrlen, RTA_VIA);
713 if (nla && nlav) {
714 NL_SET_ERR_MSG(extack,
715 "Nexthop configuration can not contain both GATEWAY and VIA");
716 return -EINVAL;
717 }
718 if (nla) {
719 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
720 extack);
721 if (ret)
722 goto errout;
723
724 if (fib_cfg.fc_gw4)
725 fib_cfg.fc_gw_family = AF_INET;
726 } else if (nlav) {
727 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
728 if (ret)
729 goto errout;
730 }
731
732 nla = nla_find(attrs, attrlen, RTA_FLOW);
733 if (nla) {
734 if (nla_len(nla) < sizeof(u32)) {
735 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
736 return -EINVAL;
737 }
738 fib_cfg.fc_flow = nla_get_u32(nla);
739 }
740
741 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
742 /* RTA_ENCAP_TYPE length checked in
743 * lwtunnel_valid_encap_type_attr
744 */
745 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
746 if (nla)
747 fib_cfg.fc_encap_type = nla_get_u16(nla);
748 }
749
750 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
751 rtnh->rtnh_hops + 1, extack);
752 if (ret)
753 goto errout;
754
755 rtnh = rtnh_next(rtnh, &remaining);
756 } endfor_nexthops(fi);
757
758 ret = -EINVAL;
759 nh = fib_info_nh(fi, 0);
760 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
761 NL_SET_ERR_MSG(extack,
762 "Nexthop device index does not match RTA_OIF");
763 goto errout;
764 }
765 if (cfg->fc_gw_family) {
766 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
767 (cfg->fc_gw_family == AF_INET &&
768 nh->fib_nh_gw4 != cfg->fc_gw4) ||
769 (cfg->fc_gw_family == AF_INET6 &&
770 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
771 NL_SET_ERR_MSG(extack,
772 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
773 goto errout;
774 }
775 }
776 #ifdef CONFIG_IP_ROUTE_CLASSID
777 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
778 NL_SET_ERR_MSG(extack,
779 "Nexthop class id does not match RTA_FLOW");
780 goto errout;
781 }
782 #endif
783 ret = 0;
784 errout:
785 return ret;
786 }
787
788 /* only called when fib_nh is integrated into fib_info */
fib_rebalance(struct fib_info * fi)789 static void fib_rebalance(struct fib_info *fi)
790 {
791 int total;
792 int w;
793
794 if (fib_info_num_path(fi) < 2)
795 return;
796
797 total = 0;
798 for_nexthops(fi) {
799 if (nh->fib_nh_flags & RTNH_F_DEAD)
800 continue;
801
802 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
803 nh->fib_nh_flags & RTNH_F_LINKDOWN)
804 continue;
805
806 total += nh->fib_nh_weight;
807 } endfor_nexthops(fi);
808
809 w = 0;
810 change_nexthops(fi) {
811 int upper_bound;
812
813 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
814 upper_bound = -1;
815 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
816 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
817 upper_bound = -1;
818 } else {
819 w += nexthop_nh->fib_nh_weight;
820 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
821 total) - 1;
822 }
823
824 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
825 } endfor_nexthops(fi);
826 }
827 #else /* CONFIG_IP_ROUTE_MULTIPATH */
828
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)829 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
830 int remaining, struct fib_config *cfg,
831 struct netlink_ext_ack *extack)
832 {
833 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
834
835 return -EINVAL;
836 }
837
838 #define fib_rebalance(fi) do { } while (0)
839
840 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
841
fib_encap_match(u16 encap_type,struct nlattr * encap,const struct fib_nh * nh,const struct fib_config * cfg,struct netlink_ext_ack * extack)842 static int fib_encap_match(u16 encap_type,
843 struct nlattr *encap,
844 const struct fib_nh *nh,
845 const struct fib_config *cfg,
846 struct netlink_ext_ack *extack)
847 {
848 struct lwtunnel_state *lwtstate;
849 int ret, result = 0;
850
851 if (encap_type == LWTUNNEL_ENCAP_NONE)
852 return 0;
853
854 ret = lwtunnel_build_state(encap_type, encap, AF_INET,
855 cfg, &lwtstate, extack);
856 if (!ret) {
857 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
858 lwtstate_free(lwtstate);
859 }
860
861 return result;
862 }
863
fib_nh_match(struct fib_config * cfg,struct fib_info * fi,struct netlink_ext_ack * extack)864 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
865 struct netlink_ext_ack *extack)
866 {
867 #ifdef CONFIG_IP_ROUTE_MULTIPATH
868 struct rtnexthop *rtnh;
869 int remaining;
870 #endif
871
872 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
873 return 1;
874
875 if (cfg->fc_nh_id) {
876 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
877 return 0;
878 return 1;
879 }
880
881 if (fi->nh) {
882 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
883 return 1;
884 return 0;
885 }
886
887 if (cfg->fc_oif || cfg->fc_gw_family) {
888 struct fib_nh *nh;
889
890 nh = fib_info_nh(fi, 0);
891 if (cfg->fc_encap) {
892 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
893 nh, cfg, extack))
894 return 1;
895 }
896 #ifdef CONFIG_IP_ROUTE_CLASSID
897 if (cfg->fc_flow &&
898 cfg->fc_flow != nh->nh_tclassid)
899 return 1;
900 #endif
901 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
902 (cfg->fc_gw_family &&
903 cfg->fc_gw_family != nh->fib_nh_gw_family))
904 return 1;
905
906 if (cfg->fc_gw_family == AF_INET &&
907 cfg->fc_gw4 != nh->fib_nh_gw4)
908 return 1;
909
910 if (cfg->fc_gw_family == AF_INET6 &&
911 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
912 return 1;
913
914 return 0;
915 }
916
917 #ifdef CONFIG_IP_ROUTE_MULTIPATH
918 if (!cfg->fc_mp)
919 return 0;
920
921 rtnh = cfg->fc_mp;
922 remaining = cfg->fc_mp_len;
923
924 for_nexthops(fi) {
925 int attrlen;
926
927 if (!rtnh_ok(rtnh, remaining))
928 return -EINVAL;
929
930 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
931 return 1;
932
933 attrlen = rtnh_attrlen(rtnh);
934 if (attrlen > 0) {
935 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
936 int err;
937
938 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
939 nlav = nla_find(attrs, attrlen, RTA_VIA);
940 if (nla && nlav) {
941 NL_SET_ERR_MSG(extack,
942 "Nexthop configuration can not contain both GATEWAY and VIA");
943 return -EINVAL;
944 }
945
946 if (nla) {
947 __be32 gw;
948
949 err = fib_gw_from_attr(&gw, nla, extack);
950 if (err)
951 return err;
952
953 if (nh->fib_nh_gw_family != AF_INET ||
954 gw != nh->fib_nh_gw4)
955 return 1;
956 } else if (nlav) {
957 struct fib_config cfg2;
958
959 err = fib_gw_from_via(&cfg2, nlav, extack);
960 if (err)
961 return err;
962
963 switch (nh->fib_nh_gw_family) {
964 case AF_INET:
965 if (cfg2.fc_gw_family != AF_INET ||
966 cfg2.fc_gw4 != nh->fib_nh_gw4)
967 return 1;
968 break;
969 case AF_INET6:
970 if (cfg2.fc_gw_family != AF_INET6 ||
971 ipv6_addr_cmp(&cfg2.fc_gw6,
972 &nh->fib_nh_gw6))
973 return 1;
974 break;
975 }
976 }
977
978 #ifdef CONFIG_IP_ROUTE_CLASSID
979 nla = nla_find(attrs, attrlen, RTA_FLOW);
980 if (nla) {
981 if (nla_len(nla) < sizeof(u32)) {
982 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
983 return -EINVAL;
984 }
985 if (nla_get_u32(nla) != nh->nh_tclassid)
986 return 1;
987 }
988 #endif
989 }
990
991 rtnh = rtnh_next(rtnh, &remaining);
992 } endfor_nexthops(fi);
993 #endif
994 return 0;
995 }
996
fib_metrics_match(struct fib_config * cfg,struct fib_info * fi)997 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
998 {
999 struct nlattr *nla;
1000 int remaining;
1001
1002 if (!cfg->fc_mx)
1003 return true;
1004
1005 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1006 int type = nla_type(nla);
1007 u32 fi_val, val;
1008
1009 if (!type)
1010 continue;
1011 if (type > RTAX_MAX)
1012 return false;
1013
1014 type = array_index_nospec(type, RTAX_MAX + 1);
1015 if (type == RTAX_CC_ALGO) {
1016 char tmp[TCP_CA_NAME_MAX];
1017 bool ecn_ca = false;
1018
1019 nla_strlcpy(tmp, nla, sizeof(tmp));
1020 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1021 } else {
1022 if (nla_len(nla) != sizeof(u32))
1023 return false;
1024 val = nla_get_u32(nla);
1025 }
1026
1027 fi_val = fi->fib_metrics->metrics[type - 1];
1028 if (type == RTAX_FEATURES)
1029 fi_val &= ~DST_FEATURE_ECN_CA;
1030
1031 if (fi_val != val)
1032 return false;
1033 }
1034
1035 return true;
1036 }
1037
fib_check_nh_v6_gw(struct net * net,struct fib_nh * nh,u32 table,struct netlink_ext_ack * extack)1038 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1039 u32 table, struct netlink_ext_ack *extack)
1040 {
1041 struct fib6_config cfg = {
1042 .fc_table = table,
1043 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1044 .fc_ifindex = nh->fib_nh_oif,
1045 .fc_gateway = nh->fib_nh_gw6,
1046 };
1047 struct fib6_nh fib6_nh = {};
1048 int err;
1049
1050 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1051 if (!err) {
1052 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1053 dev_hold(nh->fib_nh_dev);
1054 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1055 nh->fib_nh_scope = RT_SCOPE_LINK;
1056
1057 ipv6_stub->fib6_nh_release(&fib6_nh);
1058 }
1059
1060 return err;
1061 }
1062
1063 /*
1064 * Picture
1065 * -------
1066 *
1067 * Semantics of nexthop is very messy by historical reasons.
1068 * We have to take into account, that:
1069 * a) gateway can be actually local interface address,
1070 * so that gatewayed route is direct.
1071 * b) gateway must be on-link address, possibly
1072 * described not by an ifaddr, but also by a direct route.
1073 * c) If both gateway and interface are specified, they should not
1074 * contradict.
1075 * d) If we use tunnel routes, gateway could be not on-link.
1076 *
1077 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1078 * results in pretty ugly and hairy code with obscure logic.
1079 *
1080 * I chose to generalized it instead, so that the size
1081 * of code does not increase practically, but it becomes
1082 * much more general.
1083 * Every prefix is assigned a "scope" value: "host" is local address,
1084 * "link" is direct route,
1085 * [ ... "site" ... "interior" ... ]
1086 * and "universe" is true gateway route with global meaning.
1087 *
1088 * Every prefix refers to a set of "nexthop"s (gw, oif),
1089 * where gw must have narrower scope. This recursion stops
1090 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1091 * which means that gw is forced to be on link.
1092 *
1093 * Code is still hairy, but now it is apparently logically
1094 * consistent and very flexible. F.e. as by-product it allows
1095 * to co-exists in peace independent exterior and interior
1096 * routing processes.
1097 *
1098 * Normally it looks as following.
1099 *
1100 * {universe prefix} -> (gw, oif) [scope link]
1101 * |
1102 * |-> {link prefix} -> (gw, oif) [scope local]
1103 * |
1104 * |-> {local prefix} (terminal node)
1105 */
fib_check_nh_v4_gw(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1106 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1107 u8 scope, struct netlink_ext_ack *extack)
1108 {
1109 struct net_device *dev;
1110 struct fib_result res;
1111 int err = 0;
1112
1113 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1114 unsigned int addr_type;
1115
1116 if (scope >= RT_SCOPE_LINK) {
1117 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1118 return -EINVAL;
1119 }
1120 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1121 if (!dev) {
1122 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1123 return -ENODEV;
1124 }
1125 if (!(dev->flags & IFF_UP)) {
1126 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1127 return -ENETDOWN;
1128 }
1129 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1130 if (addr_type != RTN_UNICAST) {
1131 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1132 return -EINVAL;
1133 }
1134 if (!netif_carrier_ok(dev))
1135 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1136 nh->fib_nh_dev = dev;
1137 dev_hold(dev);
1138 nh->fib_nh_scope = RT_SCOPE_LINK;
1139 return 0;
1140 }
1141 rcu_read_lock();
1142 {
1143 struct fib_table *tbl = NULL;
1144 struct flowi4 fl4 = {
1145 .daddr = nh->fib_nh_gw4,
1146 .flowi4_scope = scope + 1,
1147 .flowi4_oif = nh->fib_nh_oif,
1148 .flowi4_iif = LOOPBACK_IFINDEX,
1149 };
1150
1151 /* It is not necessary, but requires a bit of thinking */
1152 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1153 fl4.flowi4_scope = RT_SCOPE_LINK;
1154
1155 if (table && table != RT_TABLE_MAIN)
1156 tbl = fib_get_table(net, table);
1157
1158 if (tbl)
1159 err = fib_table_lookup(tbl, &fl4, &res,
1160 FIB_LOOKUP_IGNORE_LINKSTATE |
1161 FIB_LOOKUP_NOREF);
1162
1163 /* on error or if no table given do full lookup. This
1164 * is needed for example when nexthops are in the local
1165 * table rather than the given table
1166 */
1167 if (!tbl || err) {
1168 err = fib_lookup(net, &fl4, &res,
1169 FIB_LOOKUP_IGNORE_LINKSTATE);
1170 }
1171
1172 if (err) {
1173 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1174 goto out;
1175 }
1176 }
1177
1178 err = -EINVAL;
1179 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1180 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1181 goto out;
1182 }
1183 nh->fib_nh_scope = res.scope;
1184 nh->fib_nh_oif = FIB_RES_OIF(res);
1185 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1186 if (!dev) {
1187 NL_SET_ERR_MSG(extack,
1188 "No egress device for nexthop gateway");
1189 goto out;
1190 }
1191 dev_hold(dev);
1192 if (!netif_carrier_ok(dev))
1193 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1194 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1195 out:
1196 rcu_read_unlock();
1197 return err;
1198 }
1199
fib_check_nh_nongw(struct net * net,struct fib_nh * nh,struct netlink_ext_ack * extack)1200 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1201 struct netlink_ext_ack *extack)
1202 {
1203 struct in_device *in_dev;
1204 int err;
1205
1206 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1207 NL_SET_ERR_MSG(extack,
1208 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1209 return -EINVAL;
1210 }
1211
1212 rcu_read_lock();
1213
1214 err = -ENODEV;
1215 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1216 if (!in_dev)
1217 goto out;
1218 err = -ENETDOWN;
1219 if (!(in_dev->dev->flags & IFF_UP)) {
1220 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1221 goto out;
1222 }
1223
1224 nh->fib_nh_dev = in_dev->dev;
1225 dev_hold(nh->fib_nh_dev);
1226 nh->fib_nh_scope = RT_SCOPE_LINK;
1227 if (!netif_carrier_ok(nh->fib_nh_dev))
1228 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1229 err = 0;
1230 out:
1231 rcu_read_unlock();
1232 return err;
1233 }
1234
fib_check_nh(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1235 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1236 struct netlink_ext_ack *extack)
1237 {
1238 int err;
1239
1240 if (nh->fib_nh_gw_family == AF_INET)
1241 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1242 else if (nh->fib_nh_gw_family == AF_INET6)
1243 err = fib_check_nh_v6_gw(net, nh, table, extack);
1244 else
1245 err = fib_check_nh_nongw(net, nh, extack);
1246
1247 return err;
1248 }
1249
fib_laddr_hashfn(__be32 val)1250 static inline unsigned int fib_laddr_hashfn(__be32 val)
1251 {
1252 unsigned int mask = (fib_info_hash_size - 1);
1253
1254 return ((__force u32)val ^
1255 ((__force u32)val >> 7) ^
1256 ((__force u32)val >> 14)) & mask;
1257 }
1258
fib_info_hash_alloc(int bytes)1259 static struct hlist_head *fib_info_hash_alloc(int bytes)
1260 {
1261 if (bytes <= PAGE_SIZE)
1262 return kzalloc(bytes, GFP_KERNEL);
1263 else
1264 return (struct hlist_head *)
1265 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1266 get_order(bytes));
1267 }
1268
fib_info_hash_free(struct hlist_head * hash,int bytes)1269 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1270 {
1271 if (!hash)
1272 return;
1273
1274 if (bytes <= PAGE_SIZE)
1275 kfree(hash);
1276 else
1277 free_pages((unsigned long) hash, get_order(bytes));
1278 }
1279
fib_info_hash_move(struct hlist_head * new_info_hash,struct hlist_head * new_laddrhash,unsigned int new_size)1280 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1281 struct hlist_head *new_laddrhash,
1282 unsigned int new_size)
1283 {
1284 struct hlist_head *old_info_hash, *old_laddrhash;
1285 unsigned int old_size = fib_info_hash_size;
1286 unsigned int i, bytes;
1287
1288 spin_lock_bh(&fib_info_lock);
1289 old_info_hash = fib_info_hash;
1290 old_laddrhash = fib_info_laddrhash;
1291 fib_info_hash_size = new_size;
1292
1293 for (i = 0; i < old_size; i++) {
1294 struct hlist_head *head = &fib_info_hash[i];
1295 struct hlist_node *n;
1296 struct fib_info *fi;
1297
1298 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1299 struct hlist_head *dest;
1300 unsigned int new_hash;
1301
1302 new_hash = fib_info_hashfn(fi);
1303 dest = &new_info_hash[new_hash];
1304 hlist_add_head(&fi->fib_hash, dest);
1305 }
1306 }
1307 fib_info_hash = new_info_hash;
1308
1309 for (i = 0; i < old_size; i++) {
1310 struct hlist_head *lhead = &fib_info_laddrhash[i];
1311 struct hlist_node *n;
1312 struct fib_info *fi;
1313
1314 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1315 struct hlist_head *ldest;
1316 unsigned int new_hash;
1317
1318 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1319 ldest = &new_laddrhash[new_hash];
1320 hlist_add_head(&fi->fib_lhash, ldest);
1321 }
1322 }
1323 fib_info_laddrhash = new_laddrhash;
1324
1325 spin_unlock_bh(&fib_info_lock);
1326
1327 bytes = old_size * sizeof(struct hlist_head *);
1328 fib_info_hash_free(old_info_hash, bytes);
1329 fib_info_hash_free(old_laddrhash, bytes);
1330 }
1331
fib_info_update_nhc_saddr(struct net * net,struct fib_nh_common * nhc,unsigned char scope)1332 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1333 unsigned char scope)
1334 {
1335 struct fib_nh *nh;
1336 __be32 saddr;
1337
1338 if (nhc->nhc_family != AF_INET)
1339 return inet_select_addr(nhc->nhc_dev, 0, scope);
1340
1341 nh = container_of(nhc, struct fib_nh, nh_common);
1342 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1343
1344 WRITE_ONCE(nh->nh_saddr, saddr);
1345 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid));
1346
1347 return saddr;
1348 }
1349
fib_result_prefsrc(struct net * net,struct fib_result * res)1350 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1351 {
1352 struct fib_nh_common *nhc = res->nhc;
1353
1354 if (res->fi->fib_prefsrc)
1355 return res->fi->fib_prefsrc;
1356
1357 if (nhc->nhc_family == AF_INET) {
1358 struct fib_nh *nh;
1359
1360 nh = container_of(nhc, struct fib_nh, nh_common);
1361 if (READ_ONCE(nh->nh_saddr_genid) ==
1362 atomic_read(&net->ipv4.dev_addr_genid))
1363 return READ_ONCE(nh->nh_saddr);
1364 }
1365
1366 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1367 }
1368
fib_valid_prefsrc(struct fib_config * cfg,__be32 fib_prefsrc)1369 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1370 {
1371 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1372 fib_prefsrc != cfg->fc_dst) {
1373 u32 tb_id = cfg->fc_table;
1374 int rc;
1375
1376 if (tb_id == RT_TABLE_MAIN)
1377 tb_id = RT_TABLE_LOCAL;
1378
1379 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1380 fib_prefsrc, tb_id);
1381
1382 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1383 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1384 fib_prefsrc, RT_TABLE_LOCAL);
1385 }
1386
1387 if (rc != RTN_LOCAL)
1388 return false;
1389 }
1390 return true;
1391 }
1392
fib_create_info(struct fib_config * cfg,struct netlink_ext_ack * extack)1393 struct fib_info *fib_create_info(struct fib_config *cfg,
1394 struct netlink_ext_ack *extack)
1395 {
1396 int err;
1397 struct fib_info *fi = NULL;
1398 struct nexthop *nh = NULL;
1399 struct fib_info *ofi;
1400 int nhs = 1;
1401 struct net *net = cfg->fc_nlinfo.nl_net;
1402
1403 if (cfg->fc_type > RTN_MAX)
1404 goto err_inval;
1405
1406 /* Fast check to catch the most weird cases */
1407 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1408 NL_SET_ERR_MSG(extack, "Invalid scope");
1409 goto err_inval;
1410 }
1411
1412 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1413 NL_SET_ERR_MSG(extack,
1414 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1415 goto err_inval;
1416 }
1417
1418 if (cfg->fc_nh_id) {
1419 if (!cfg->fc_mx) {
1420 fi = fib_find_info_nh(net, cfg);
1421 if (fi) {
1422 fi->fib_treeref++;
1423 return fi;
1424 }
1425 }
1426
1427 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1428 if (!nh) {
1429 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1430 goto err_inval;
1431 }
1432 nhs = 0;
1433 }
1434
1435 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1436 if (cfg->fc_mp) {
1437 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1438 if (nhs == 0)
1439 goto err_inval;
1440 }
1441 #endif
1442
1443 err = -ENOBUFS;
1444 if (fib_info_cnt >= fib_info_hash_size) {
1445 unsigned int new_size = fib_info_hash_size << 1;
1446 struct hlist_head *new_info_hash;
1447 struct hlist_head *new_laddrhash;
1448 unsigned int bytes;
1449
1450 if (!new_size)
1451 new_size = 16;
1452 bytes = new_size * sizeof(struct hlist_head *);
1453 new_info_hash = fib_info_hash_alloc(bytes);
1454 new_laddrhash = fib_info_hash_alloc(bytes);
1455 if (!new_info_hash || !new_laddrhash) {
1456 fib_info_hash_free(new_info_hash, bytes);
1457 fib_info_hash_free(new_laddrhash, bytes);
1458 } else
1459 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1460
1461 if (!fib_info_hash_size)
1462 goto failure;
1463 }
1464
1465 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1466 if (!fi)
1467 goto failure;
1468 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1469 cfg->fc_mx_len, extack);
1470 if (IS_ERR(fi->fib_metrics)) {
1471 err = PTR_ERR(fi->fib_metrics);
1472 kfree(fi);
1473 return ERR_PTR(err);
1474 }
1475
1476 fib_info_cnt++;
1477 fi->fib_net = net;
1478 fi->fib_protocol = cfg->fc_protocol;
1479 fi->fib_scope = cfg->fc_scope;
1480 fi->fib_flags = cfg->fc_flags;
1481 fi->fib_priority = cfg->fc_priority;
1482 fi->fib_prefsrc = cfg->fc_prefsrc;
1483 fi->fib_type = cfg->fc_type;
1484 fi->fib_tb_id = cfg->fc_table;
1485
1486 fi->fib_nhs = nhs;
1487 if (nh) {
1488 if (!nexthop_get(nh)) {
1489 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1490 err = -EINVAL;
1491 } else {
1492 err = 0;
1493 fi->nh = nh;
1494 }
1495 } else {
1496 change_nexthops(fi) {
1497 nexthop_nh->nh_parent = fi;
1498 } endfor_nexthops(fi)
1499
1500 if (cfg->fc_mp)
1501 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1502 extack);
1503 else
1504 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1505 }
1506
1507 if (err != 0)
1508 goto failure;
1509
1510 if (fib_props[cfg->fc_type].error) {
1511 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1512 NL_SET_ERR_MSG(extack,
1513 "Gateway, device and multipath can not be specified for this route type");
1514 goto err_inval;
1515 }
1516 goto link_it;
1517 } else {
1518 switch (cfg->fc_type) {
1519 case RTN_UNICAST:
1520 case RTN_LOCAL:
1521 case RTN_BROADCAST:
1522 case RTN_ANYCAST:
1523 case RTN_MULTICAST:
1524 break;
1525 default:
1526 NL_SET_ERR_MSG(extack, "Invalid route type");
1527 goto err_inval;
1528 }
1529 }
1530
1531 if (cfg->fc_scope > RT_SCOPE_HOST) {
1532 NL_SET_ERR_MSG(extack, "Invalid scope");
1533 goto err_inval;
1534 }
1535
1536 if (fi->nh) {
1537 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1538 if (err)
1539 goto failure;
1540 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1541 struct fib_nh *nh = fi->fib_nh;
1542
1543 /* Local address is added. */
1544 if (nhs != 1) {
1545 NL_SET_ERR_MSG(extack,
1546 "Route with host scope can not have multiple nexthops");
1547 goto err_inval;
1548 }
1549 if (nh->fib_nh_gw_family) {
1550 NL_SET_ERR_MSG(extack,
1551 "Route with host scope can not have a gateway");
1552 goto err_inval;
1553 }
1554 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1555 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1556 err = -ENODEV;
1557 if (!nh->fib_nh_dev)
1558 goto failure;
1559 } else {
1560 int linkdown = 0;
1561
1562 change_nexthops(fi) {
1563 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1564 cfg->fc_table, cfg->fc_scope,
1565 extack);
1566 if (err != 0)
1567 goto failure;
1568 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1569 linkdown++;
1570 } endfor_nexthops(fi)
1571 if (linkdown == fi->fib_nhs)
1572 fi->fib_flags |= RTNH_F_LINKDOWN;
1573 }
1574
1575 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1576 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1577 goto err_inval;
1578 }
1579
1580 if (!fi->nh) {
1581 change_nexthops(fi) {
1582 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1583 fi->fib_scope);
1584 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1585 fi->fib_nh_is_v6 = true;
1586 } endfor_nexthops(fi)
1587
1588 fib_rebalance(fi);
1589 }
1590
1591 link_it:
1592 ofi = fib_find_info(fi);
1593 if (ofi) {
1594 /* fib_table_lookup() should not see @fi yet. */
1595 fi->fib_dead = 1;
1596 free_fib_info(fi);
1597 ofi->fib_treeref++;
1598 return ofi;
1599 }
1600
1601 fi->fib_treeref++;
1602 refcount_set(&fi->fib_clntref, 1);
1603 spin_lock_bh(&fib_info_lock);
1604 hlist_add_head(&fi->fib_hash,
1605 &fib_info_hash[fib_info_hashfn(fi)]);
1606 if (fi->fib_prefsrc) {
1607 struct hlist_head *head;
1608
1609 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1610 hlist_add_head(&fi->fib_lhash, head);
1611 }
1612 if (fi->nh) {
1613 list_add(&fi->nh_list, &nh->fi_list);
1614 } else {
1615 change_nexthops(fi) {
1616 struct hlist_head *head;
1617
1618 if (!nexthop_nh->fib_nh_dev)
1619 continue;
1620 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
1621 hlist_add_head(&nexthop_nh->nh_hash, head);
1622 } endfor_nexthops(fi)
1623 }
1624 spin_unlock_bh(&fib_info_lock);
1625 return fi;
1626
1627 err_inval:
1628 err = -EINVAL;
1629
1630 failure:
1631 if (fi) {
1632 /* fib_table_lookup() should not see @fi yet. */
1633 fi->fib_dead = 1;
1634 free_fib_info(fi);
1635 }
1636
1637 return ERR_PTR(err);
1638 }
1639
fib_nexthop_info(struct sk_buff * skb,const struct fib_nh_common * nhc,u8 rt_family,unsigned char * flags,bool skip_oif)1640 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1641 u8 rt_family, unsigned char *flags, bool skip_oif)
1642 {
1643 if (nhc->nhc_flags & RTNH_F_DEAD)
1644 *flags |= RTNH_F_DEAD;
1645
1646 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1647 *flags |= RTNH_F_LINKDOWN;
1648
1649 rcu_read_lock();
1650 switch (nhc->nhc_family) {
1651 case AF_INET:
1652 if (ip_ignore_linkdown(nhc->nhc_dev))
1653 *flags |= RTNH_F_DEAD;
1654 break;
1655 case AF_INET6:
1656 if (ip6_ignore_linkdown(nhc->nhc_dev))
1657 *flags |= RTNH_F_DEAD;
1658 break;
1659 }
1660 rcu_read_unlock();
1661 }
1662
1663 switch (nhc->nhc_gw_family) {
1664 case AF_INET:
1665 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1666 goto nla_put_failure;
1667 break;
1668 case AF_INET6:
1669 /* if gateway family does not match nexthop family
1670 * gateway is encoded as RTA_VIA
1671 */
1672 if (rt_family != nhc->nhc_gw_family) {
1673 int alen = sizeof(struct in6_addr);
1674 struct nlattr *nla;
1675 struct rtvia *via;
1676
1677 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1678 if (!nla)
1679 goto nla_put_failure;
1680
1681 via = nla_data(nla);
1682 via->rtvia_family = AF_INET6;
1683 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1684 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1685 &nhc->nhc_gw.ipv6) < 0) {
1686 goto nla_put_failure;
1687 }
1688 break;
1689 }
1690
1691 *flags |= (nhc->nhc_flags & RTNH_F_ONLINK);
1692 if (nhc->nhc_flags & RTNH_F_OFFLOAD)
1693 *flags |= RTNH_F_OFFLOAD;
1694
1695 if (!skip_oif && nhc->nhc_dev &&
1696 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1697 goto nla_put_failure;
1698
1699 if (nhc->nhc_lwtstate &&
1700 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1701 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1702 goto nla_put_failure;
1703
1704 return 0;
1705
1706 nla_put_failure:
1707 return -EMSGSIZE;
1708 }
1709 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1710
1711 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
fib_add_nexthop(struct sk_buff * skb,const struct fib_nh_common * nhc,int nh_weight,u8 rt_family,u32 nh_tclassid)1712 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1713 int nh_weight, u8 rt_family, u32 nh_tclassid)
1714 {
1715 const struct net_device *dev = nhc->nhc_dev;
1716 struct rtnexthop *rtnh;
1717 unsigned char flags = 0;
1718
1719 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1720 if (!rtnh)
1721 goto nla_put_failure;
1722
1723 rtnh->rtnh_hops = nh_weight - 1;
1724 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1725
1726 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1727 goto nla_put_failure;
1728
1729 rtnh->rtnh_flags = flags;
1730
1731 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1732 goto nla_put_failure;
1733
1734 /* length of rtnetlink header + attributes */
1735 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1736
1737 return 0;
1738
1739 nla_put_failure:
1740 return -EMSGSIZE;
1741 }
1742 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1743 #endif
1744
1745 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1746 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1747 {
1748 struct nlattr *mp;
1749
1750 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1751 if (!mp)
1752 goto nla_put_failure;
1753
1754 if (unlikely(fi->nh)) {
1755 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1756 goto nla_put_failure;
1757 goto mp_end;
1758 }
1759
1760 for_nexthops(fi) {
1761 u32 nh_tclassid = 0;
1762 #ifdef CONFIG_IP_ROUTE_CLASSID
1763 nh_tclassid = nh->nh_tclassid;
1764 #endif
1765 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1766 AF_INET, nh_tclassid) < 0)
1767 goto nla_put_failure;
1768 } endfor_nexthops(fi);
1769
1770 mp_end:
1771 nla_nest_end(skb, mp);
1772
1773 return 0;
1774
1775 nla_put_failure:
1776 return -EMSGSIZE;
1777 }
1778 #else
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1779 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1780 {
1781 return 0;
1782 }
1783 #endif
1784
fib_dump_info(struct sk_buff * skb,u32 portid,u32 seq,int event,u32 tb_id,u8 type,__be32 dst,int dst_len,u8 tos,struct fib_info * fi,unsigned int flags)1785 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1786 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1787 struct fib_info *fi, unsigned int flags)
1788 {
1789 unsigned int nhs = fib_info_num_path(fi);
1790 struct nlmsghdr *nlh;
1791 struct rtmsg *rtm;
1792
1793 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1794 if (!nlh)
1795 return -EMSGSIZE;
1796
1797 rtm = nlmsg_data(nlh);
1798 rtm->rtm_family = AF_INET;
1799 rtm->rtm_dst_len = dst_len;
1800 rtm->rtm_src_len = 0;
1801 rtm->rtm_tos = tos;
1802 if (tb_id < 256)
1803 rtm->rtm_table = tb_id;
1804 else
1805 rtm->rtm_table = RT_TABLE_COMPAT;
1806 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1807 goto nla_put_failure;
1808 rtm->rtm_type = type;
1809 rtm->rtm_flags = fi->fib_flags;
1810 rtm->rtm_scope = fi->fib_scope;
1811 rtm->rtm_protocol = fi->fib_protocol;
1812
1813 if (rtm->rtm_dst_len &&
1814 nla_put_in_addr(skb, RTA_DST, dst))
1815 goto nla_put_failure;
1816 if (fi->fib_priority &&
1817 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1818 goto nla_put_failure;
1819 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1820 goto nla_put_failure;
1821
1822 if (fi->fib_prefsrc &&
1823 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1824 goto nla_put_failure;
1825
1826 if (fi->nh) {
1827 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1828 goto nla_put_failure;
1829 if (nexthop_is_blackhole(fi->nh))
1830 rtm->rtm_type = RTN_BLACKHOLE;
1831 }
1832
1833 if (nhs == 1) {
1834 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1835 unsigned char flags = 0;
1836
1837 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1838 goto nla_put_failure;
1839
1840 rtm->rtm_flags = flags;
1841 #ifdef CONFIG_IP_ROUTE_CLASSID
1842 if (nhc->nhc_family == AF_INET) {
1843 struct fib_nh *nh;
1844
1845 nh = container_of(nhc, struct fib_nh, nh_common);
1846 if (nh->nh_tclassid &&
1847 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1848 goto nla_put_failure;
1849 }
1850 #endif
1851 } else {
1852 if (fib_add_multipath(skb, fi) < 0)
1853 goto nla_put_failure;
1854 }
1855
1856 nlmsg_end(skb, nlh);
1857 return 0;
1858
1859 nla_put_failure:
1860 nlmsg_cancel(skb, nlh);
1861 return -EMSGSIZE;
1862 }
1863
1864 /*
1865 * Update FIB if:
1866 * - local address disappeared -> we must delete all the entries
1867 * referring to it.
1868 * - device went down -> we must shutdown all nexthops going via it.
1869 */
fib_sync_down_addr(struct net_device * dev,__be32 local)1870 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1871 {
1872 int ret = 0;
1873 unsigned int hash = fib_laddr_hashfn(local);
1874 struct hlist_head *head = &fib_info_laddrhash[hash];
1875 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1876 struct net *net = dev_net(dev);
1877 struct fib_info *fi;
1878
1879 if (!fib_info_laddrhash || local == 0)
1880 return 0;
1881
1882 hlist_for_each_entry(fi, head, fib_lhash) {
1883 if (!net_eq(fi->fib_net, net) ||
1884 fi->fib_tb_id != tb_id)
1885 continue;
1886 if (fi->fib_prefsrc == local) {
1887 fi->fib_flags |= RTNH_F_DEAD;
1888 ret++;
1889 }
1890 }
1891 return ret;
1892 }
1893
call_fib_nh_notifiers(struct fib_nh * nh,enum fib_event_type event_type)1894 static int call_fib_nh_notifiers(struct fib_nh *nh,
1895 enum fib_event_type event_type)
1896 {
1897 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1898 struct fib_nh_notifier_info info = {
1899 .fib_nh = nh,
1900 };
1901
1902 switch (event_type) {
1903 case FIB_EVENT_NH_ADD:
1904 if (nh->fib_nh_flags & RTNH_F_DEAD)
1905 break;
1906 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1907 break;
1908 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1909 &info.info);
1910 case FIB_EVENT_NH_DEL:
1911 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1912 (nh->fib_nh_flags & RTNH_F_DEAD))
1913 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1914 event_type, &info.info);
1915 default:
1916 break;
1917 }
1918
1919 return NOTIFY_DONE;
1920 }
1921
1922 /* Update the PMTU of exceptions when:
1923 * - the new MTU of the first hop becomes smaller than the PMTU
1924 * - the old MTU was the same as the PMTU, and it limited discovery of
1925 * larger MTUs on the path. With that limit raised, we can now
1926 * discover larger MTUs
1927 * A special case is locked exceptions, for which the PMTU is smaller
1928 * than the minimal accepted PMTU:
1929 * - if the new MTU is greater than the PMTU, don't make any change
1930 * - otherwise, unlock and set PMTU
1931 */
fib_nhc_update_mtu(struct fib_nh_common * nhc,u32 new,u32 orig)1932 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1933 {
1934 struct fnhe_hash_bucket *bucket;
1935 int i;
1936
1937 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1938 if (!bucket)
1939 return;
1940
1941 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1942 struct fib_nh_exception *fnhe;
1943
1944 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1945 fnhe;
1946 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1947 if (fnhe->fnhe_mtu_locked) {
1948 if (new <= fnhe->fnhe_pmtu) {
1949 fnhe->fnhe_pmtu = new;
1950 fnhe->fnhe_mtu_locked = false;
1951 }
1952 } else if (new < fnhe->fnhe_pmtu ||
1953 orig == fnhe->fnhe_pmtu) {
1954 fnhe->fnhe_pmtu = new;
1955 }
1956 }
1957 }
1958 }
1959
fib_sync_mtu(struct net_device * dev,u32 orig_mtu)1960 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1961 {
1962 struct hlist_head *head = fib_info_devhash_bucket(dev);
1963 struct fib_nh *nh;
1964
1965 hlist_for_each_entry(nh, head, nh_hash) {
1966 if (nh->fib_nh_dev == dev)
1967 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1968 }
1969 }
1970
1971 /* Event force Flags Description
1972 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1973 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1974 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1975 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1976 *
1977 * only used when fib_nh is built into fib_info
1978 */
fib_sync_down_dev(struct net_device * dev,unsigned long event,bool force)1979 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1980 {
1981 struct hlist_head *head = fib_info_devhash_bucket(dev);
1982 struct fib_info *prev_fi = NULL;
1983 int scope = RT_SCOPE_NOWHERE;
1984 struct fib_nh *nh;
1985 int ret = 0;
1986
1987 if (force)
1988 scope = -1;
1989
1990 hlist_for_each_entry(nh, head, nh_hash) {
1991 struct fib_info *fi = nh->nh_parent;
1992 int dead;
1993
1994 BUG_ON(!fi->fib_nhs);
1995 if (nh->fib_nh_dev != dev || fi == prev_fi)
1996 continue;
1997 prev_fi = fi;
1998 dead = 0;
1999 change_nexthops(fi) {
2000 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
2001 dead++;
2002 else if (nexthop_nh->fib_nh_dev == dev &&
2003 nexthop_nh->fib_nh_scope != scope) {
2004 switch (event) {
2005 case NETDEV_DOWN:
2006 case NETDEV_UNREGISTER:
2007 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
2008 /* fall through */
2009 case NETDEV_CHANGE:
2010 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
2011 break;
2012 }
2013 call_fib_nh_notifiers(nexthop_nh,
2014 FIB_EVENT_NH_DEL);
2015 dead++;
2016 }
2017 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2018 if (event == NETDEV_UNREGISTER &&
2019 nexthop_nh->fib_nh_dev == dev) {
2020 dead = fi->fib_nhs;
2021 break;
2022 }
2023 #endif
2024 } endfor_nexthops(fi)
2025 if (dead == fi->fib_nhs) {
2026 switch (event) {
2027 case NETDEV_DOWN:
2028 case NETDEV_UNREGISTER:
2029 fi->fib_flags |= RTNH_F_DEAD;
2030 /* fall through */
2031 case NETDEV_CHANGE:
2032 fi->fib_flags |= RTNH_F_LINKDOWN;
2033 break;
2034 }
2035 ret++;
2036 }
2037
2038 fib_rebalance(fi);
2039 }
2040
2041 return ret;
2042 }
2043
2044 /* Must be invoked inside of an RCU protected region. */
fib_select_default(const struct flowi4 * flp,struct fib_result * res)2045 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2046 {
2047 struct fib_info *fi = NULL, *last_resort = NULL;
2048 struct hlist_head *fa_head = res->fa_head;
2049 struct fib_table *tb = res->table;
2050 u8 slen = 32 - res->prefixlen;
2051 int order = -1, last_idx = -1;
2052 struct fib_alias *fa, *fa1 = NULL;
2053 u32 last_prio = res->fi->fib_priority;
2054 u8 last_tos = 0;
2055
2056 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2057 struct fib_info *next_fi = fa->fa_info;
2058 struct fib_nh_common *nhc;
2059
2060 if (fa->fa_slen != slen)
2061 continue;
2062 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2063 continue;
2064 if (fa->tb_id != tb->tb_id)
2065 continue;
2066 if (next_fi->fib_priority > last_prio &&
2067 fa->fa_tos == last_tos) {
2068 if (last_tos)
2069 continue;
2070 break;
2071 }
2072 if (next_fi->fib_flags & RTNH_F_DEAD)
2073 continue;
2074 last_tos = fa->fa_tos;
2075 last_prio = next_fi->fib_priority;
2076
2077 if (next_fi->fib_scope != res->scope ||
2078 fa->fa_type != RTN_UNICAST)
2079 continue;
2080
2081 nhc = fib_info_nhc(next_fi, 0);
2082 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2083 continue;
2084
2085 fib_alias_accessed(fa);
2086
2087 if (!fi) {
2088 if (next_fi != res->fi)
2089 break;
2090 fa1 = fa;
2091 } else if (!fib_detect_death(fi, order, &last_resort,
2092 &last_idx, fa1->fa_default)) {
2093 fib_result_assign(res, fi);
2094 fa1->fa_default = order;
2095 goto out;
2096 }
2097 fi = next_fi;
2098 order++;
2099 }
2100
2101 if (order <= 0 || !fi) {
2102 if (fa1)
2103 fa1->fa_default = -1;
2104 goto out;
2105 }
2106
2107 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2108 fa1->fa_default)) {
2109 fib_result_assign(res, fi);
2110 fa1->fa_default = order;
2111 goto out;
2112 }
2113
2114 if (last_idx >= 0)
2115 fib_result_assign(res, last_resort);
2116 fa1->fa_default = last_idx;
2117 out:
2118 return;
2119 }
2120
2121 /*
2122 * Dead device goes up. We wake up dead nexthops.
2123 * It takes sense only on multipath routes.
2124 *
2125 * only used when fib_nh is built into fib_info
2126 */
fib_sync_up(struct net_device * dev,unsigned char nh_flags)2127 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2128 {
2129 struct fib_info *prev_fi;
2130 struct hlist_head *head;
2131 struct fib_nh *nh;
2132 int ret;
2133
2134 if (!(dev->flags & IFF_UP))
2135 return 0;
2136
2137 if (nh_flags & RTNH_F_DEAD) {
2138 unsigned int flags = dev_get_flags(dev);
2139
2140 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2141 nh_flags |= RTNH_F_LINKDOWN;
2142 }
2143
2144 prev_fi = NULL;
2145 head = fib_info_devhash_bucket(dev);
2146 ret = 0;
2147
2148 hlist_for_each_entry(nh, head, nh_hash) {
2149 struct fib_info *fi = nh->nh_parent;
2150 int alive;
2151
2152 BUG_ON(!fi->fib_nhs);
2153 if (nh->fib_nh_dev != dev || fi == prev_fi)
2154 continue;
2155
2156 prev_fi = fi;
2157 alive = 0;
2158 change_nexthops(fi) {
2159 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2160 alive++;
2161 continue;
2162 }
2163 if (!nexthop_nh->fib_nh_dev ||
2164 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2165 continue;
2166 if (nexthop_nh->fib_nh_dev != dev ||
2167 !__in_dev_get_rtnl(dev))
2168 continue;
2169 alive++;
2170 nexthop_nh->fib_nh_flags &= ~nh_flags;
2171 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2172 } endfor_nexthops(fi)
2173
2174 if (alive > 0) {
2175 fi->fib_flags &= ~nh_flags;
2176 ret++;
2177 }
2178
2179 fib_rebalance(fi);
2180 }
2181
2182 return ret;
2183 }
2184
2185 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_good_nh(const struct fib_nh * nh)2186 static bool fib_good_nh(const struct fib_nh *nh)
2187 {
2188 int state = NUD_REACHABLE;
2189
2190 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2191 struct neighbour *n;
2192
2193 rcu_read_lock_bh();
2194
2195 if (likely(nh->fib_nh_gw_family == AF_INET))
2196 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2197 (__force u32)nh->fib_nh_gw4);
2198 else if (nh->fib_nh_gw_family == AF_INET6)
2199 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2200 &nh->fib_nh_gw6);
2201 else
2202 n = NULL;
2203 if (n)
2204 state = n->nud_state;
2205
2206 rcu_read_unlock_bh();
2207 }
2208
2209 return !!(state & NUD_VALID);
2210 }
2211
fib_select_multipath(struct fib_result * res,int hash)2212 void fib_select_multipath(struct fib_result *res, int hash)
2213 {
2214 struct fib_info *fi = res->fi;
2215 struct net *net = fi->fib_net;
2216 bool first = false;
2217
2218 if (unlikely(res->fi->nh)) {
2219 nexthop_path_fib_result(res, hash);
2220 return;
2221 }
2222
2223 change_nexthops(fi) {
2224 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) {
2225 if (!fib_good_nh(nexthop_nh))
2226 continue;
2227 if (!first) {
2228 res->nh_sel = nhsel;
2229 res->nhc = &nexthop_nh->nh_common;
2230 first = true;
2231 }
2232 }
2233
2234 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2235 continue;
2236
2237 res->nh_sel = nhsel;
2238 res->nhc = &nexthop_nh->nh_common;
2239 return;
2240 } endfor_nexthops(fi);
2241 }
2242 #endif
2243
fib_select_path(struct net * net,struct fib_result * res,struct flowi4 * fl4,const struct sk_buff * skb)2244 void fib_select_path(struct net *net, struct fib_result *res,
2245 struct flowi4 *fl4, const struct sk_buff *skb)
2246 {
2247 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2248 goto check_saddr;
2249
2250 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2251 if (fib_info_num_path(res->fi) > 1) {
2252 int h = fib_multipath_hash(net, fl4, skb, NULL);
2253
2254 fib_select_multipath(res, h);
2255 }
2256 else
2257 #endif
2258 if (!res->prefixlen &&
2259 res->table->tb_num_default > 1 &&
2260 res->type == RTN_UNICAST)
2261 fib_select_default(fl4, res);
2262
2263 check_saddr:
2264 if (!fl4->saddr)
2265 fl4->saddr = fib_result_prefsrc(net, res);
2266 }
2267