1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: semantics.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/uaccess.h>
13 #include <linux/bitops.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/jiffies.h>
17 #include <linux/mm.h>
18 #include <linux/string.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/errno.h>
22 #include <linux/in.h>
23 #include <linux/inet.h>
24 #include <linux/inetdevice.h>
25 #include <linux/netdevice.h>
26 #include <linux/if_arp.h>
27 #include <linux/proc_fs.h>
28 #include <linux/skbuff.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/netlink.h>
32
33 #include <net/arp.h>
34 #include <net/ip.h>
35 #include <net/protocol.h>
36 #include <net/route.h>
37 #include <net/tcp.h>
38 #include <net/sock.h>
39 #include <net/ip_fib.h>
40 #include <net/ip6_fib.h>
41 #include <net/nexthop.h>
42 #include <net/netlink.h>
43 #include <net/rtnh.h>
44 #include <net/lwtunnel.h>
45 #include <net/fib_notifier.h>
46 #include <net/addrconf.h>
47
48 #include "fib_lookup.h"
49
50 static DEFINE_SPINLOCK(fib_info_lock);
51 static struct hlist_head *fib_info_hash;
52 static struct hlist_head *fib_info_laddrhash;
53 static unsigned int fib_info_hash_size;
54 static unsigned int fib_info_cnt;
55
56 #define DEVINDEX_HASHBITS 8
57 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
58 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
59
60 /* for_nexthops and change_nexthops only used when nexthop object
61 * is not set in a fib_info. The logic within can reference fib_nh.
62 */
63 #ifdef CONFIG_IP_ROUTE_MULTIPATH
64
65 #define for_nexthops(fi) { \
66 int nhsel; const struct fib_nh *nh; \
67 for (nhsel = 0, nh = (fi)->fib_nh; \
68 nhsel < fib_info_num_path((fi)); \
69 nh++, nhsel++)
70
71 #define change_nexthops(fi) { \
72 int nhsel; struct fib_nh *nexthop_nh; \
73 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
74 nhsel < fib_info_num_path((fi)); \
75 nexthop_nh++, nhsel++)
76
77 #else /* CONFIG_IP_ROUTE_MULTIPATH */
78
79 /* Hope, that gcc will optimize it to get rid of dummy loop */
80
81 #define for_nexthops(fi) { \
82 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
83 for (nhsel = 0; nhsel < 1; nhsel++)
84
85 #define change_nexthops(fi) { \
86 int nhsel; \
87 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
88 for (nhsel = 0; nhsel < 1; nhsel++)
89
90 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
91
92 #define endfor_nexthops(fi) }
93
94
95 const struct fib_prop fib_props[RTN_MAX + 1] = {
96 [RTN_UNSPEC] = {
97 .error = 0,
98 .scope = RT_SCOPE_NOWHERE,
99 },
100 [RTN_UNICAST] = {
101 .error = 0,
102 .scope = RT_SCOPE_UNIVERSE,
103 },
104 [RTN_LOCAL] = {
105 .error = 0,
106 .scope = RT_SCOPE_HOST,
107 },
108 [RTN_BROADCAST] = {
109 .error = 0,
110 .scope = RT_SCOPE_LINK,
111 },
112 [RTN_ANYCAST] = {
113 .error = 0,
114 .scope = RT_SCOPE_LINK,
115 },
116 [RTN_MULTICAST] = {
117 .error = 0,
118 .scope = RT_SCOPE_UNIVERSE,
119 },
120 [RTN_BLACKHOLE] = {
121 .error = -EINVAL,
122 .scope = RT_SCOPE_UNIVERSE,
123 },
124 [RTN_UNREACHABLE] = {
125 .error = -EHOSTUNREACH,
126 .scope = RT_SCOPE_UNIVERSE,
127 },
128 [RTN_PROHIBIT] = {
129 .error = -EACCES,
130 .scope = RT_SCOPE_UNIVERSE,
131 },
132 [RTN_THROW] = {
133 .error = -EAGAIN,
134 .scope = RT_SCOPE_UNIVERSE,
135 },
136 [RTN_NAT] = {
137 .error = -EINVAL,
138 .scope = RT_SCOPE_NOWHERE,
139 },
140 [RTN_XRESOLVE] = {
141 .error = -EINVAL,
142 .scope = RT_SCOPE_NOWHERE,
143 },
144 };
145
rt_fibinfo_free(struct rtable __rcu ** rtp)146 static void rt_fibinfo_free(struct rtable __rcu **rtp)
147 {
148 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
149
150 if (!rt)
151 return;
152
153 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
154 * because we waited an RCU grace period before calling
155 * free_fib_info_rcu()
156 */
157
158 dst_dev_put(&rt->dst);
159 dst_release_immediate(&rt->dst);
160 }
161
free_nh_exceptions(struct fib_nh_common * nhc)162 static void free_nh_exceptions(struct fib_nh_common *nhc)
163 {
164 struct fnhe_hash_bucket *hash;
165 int i;
166
167 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
168 if (!hash)
169 return;
170 for (i = 0; i < FNHE_HASH_SIZE; i++) {
171 struct fib_nh_exception *fnhe;
172
173 fnhe = rcu_dereference_protected(hash[i].chain, 1);
174 while (fnhe) {
175 struct fib_nh_exception *next;
176
177 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
178
179 rt_fibinfo_free(&fnhe->fnhe_rth_input);
180 rt_fibinfo_free(&fnhe->fnhe_rth_output);
181
182 kfree(fnhe);
183
184 fnhe = next;
185 }
186 }
187 kfree(hash);
188 }
189
rt_fibinfo_free_cpus(struct rtable __rcu * __percpu * rtp)190 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
191 {
192 int cpu;
193
194 if (!rtp)
195 return;
196
197 for_each_possible_cpu(cpu) {
198 struct rtable *rt;
199
200 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
201 if (rt) {
202 dst_dev_put(&rt->dst);
203 dst_release_immediate(&rt->dst);
204 }
205 }
206 free_percpu(rtp);
207 }
208
fib_nh_common_release(struct fib_nh_common * nhc)209 void fib_nh_common_release(struct fib_nh_common *nhc)
210 {
211 if (nhc->nhc_dev)
212 dev_put(nhc->nhc_dev);
213
214 lwtstate_put(nhc->nhc_lwtstate);
215 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
216 rt_fibinfo_free(&nhc->nhc_rth_input);
217 free_nh_exceptions(nhc);
218 }
219 EXPORT_SYMBOL_GPL(fib_nh_common_release);
220
fib_nh_release(struct net * net,struct fib_nh * fib_nh)221 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
222 {
223 #ifdef CONFIG_IP_ROUTE_CLASSID
224 if (fib_nh->nh_tclassid)
225 net->ipv4.fib_num_tclassid_users--;
226 #endif
227 fib_nh_common_release(&fib_nh->nh_common);
228 }
229
230 /* Release a nexthop info record */
free_fib_info_rcu(struct rcu_head * head)231 static void free_fib_info_rcu(struct rcu_head *head)
232 {
233 struct fib_info *fi = container_of(head, struct fib_info, rcu);
234
235 if (fi->nh) {
236 nexthop_put(fi->nh);
237 } else {
238 change_nexthops(fi) {
239 fib_nh_release(fi->fib_net, nexthop_nh);
240 } endfor_nexthops(fi);
241 }
242
243 ip_fib_metrics_put(fi->fib_metrics);
244
245 kfree(fi);
246 }
247
free_fib_info(struct fib_info * fi)248 void free_fib_info(struct fib_info *fi)
249 {
250 if (fi->fib_dead == 0) {
251 pr_warn("Freeing alive fib_info %p\n", fi);
252 return;
253 }
254 fib_info_cnt--;
255
256 call_rcu(&fi->rcu, free_fib_info_rcu);
257 }
258 EXPORT_SYMBOL_GPL(free_fib_info);
259
fib_release_info(struct fib_info * fi)260 void fib_release_info(struct fib_info *fi)
261 {
262 spin_lock_bh(&fib_info_lock);
263 if (fi && --fi->fib_treeref == 0) {
264 hlist_del(&fi->fib_hash);
265 if (fi->fib_prefsrc)
266 hlist_del(&fi->fib_lhash);
267 if (fi->nh) {
268 list_del(&fi->nh_list);
269 } else {
270 change_nexthops(fi) {
271 if (!nexthop_nh->fib_nh_dev)
272 continue;
273 hlist_del(&nexthop_nh->nh_hash);
274 } endfor_nexthops(fi)
275 }
276 fi->fib_dead = 1;
277 fib_info_put(fi);
278 }
279 spin_unlock_bh(&fib_info_lock);
280 }
281
nh_comp(struct fib_info * fi,struct fib_info * ofi)282 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
283 {
284 const struct fib_nh *onh;
285
286 if (fi->nh || ofi->nh)
287 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
288
289 if (ofi->fib_nhs == 0)
290 return 0;
291
292 for_nexthops(fi) {
293 onh = fib_info_nh(ofi, nhsel);
294
295 if (nh->fib_nh_oif != onh->fib_nh_oif ||
296 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
297 nh->fib_nh_scope != onh->fib_nh_scope ||
298 #ifdef CONFIG_IP_ROUTE_MULTIPATH
299 nh->fib_nh_weight != onh->fib_nh_weight ||
300 #endif
301 #ifdef CONFIG_IP_ROUTE_CLASSID
302 nh->nh_tclassid != onh->nh_tclassid ||
303 #endif
304 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
305 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
306 return -1;
307
308 if (nh->fib_nh_gw_family == AF_INET &&
309 nh->fib_nh_gw4 != onh->fib_nh_gw4)
310 return -1;
311
312 if (nh->fib_nh_gw_family == AF_INET6 &&
313 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
314 return -1;
315 } endfor_nexthops(fi);
316 return 0;
317 }
318
fib_devindex_hashfn(unsigned int val)319 static inline unsigned int fib_devindex_hashfn(unsigned int val)
320 {
321 unsigned int mask = DEVINDEX_HASHSIZE - 1;
322
323 return (val ^
324 (val >> DEVINDEX_HASHBITS) ^
325 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
326 }
327
fib_info_hashfn_1(int init_val,u8 protocol,u8 scope,u32 prefsrc,u32 priority)328 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
329 u32 prefsrc, u32 priority)
330 {
331 unsigned int val = init_val;
332
333 val ^= (protocol << 8) | scope;
334 val ^= prefsrc;
335 val ^= priority;
336
337 return val;
338 }
339
fib_info_hashfn_result(unsigned int val)340 static unsigned int fib_info_hashfn_result(unsigned int val)
341 {
342 unsigned int mask = (fib_info_hash_size - 1);
343
344 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
345 }
346
fib_info_hashfn(struct fib_info * fi)347 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
348 {
349 unsigned int val;
350
351 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
352 fi->fib_scope, (__force u32)fi->fib_prefsrc,
353 fi->fib_priority);
354
355 if (fi->nh) {
356 val ^= fib_devindex_hashfn(fi->nh->id);
357 } else {
358 for_nexthops(fi) {
359 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
360 } endfor_nexthops(fi)
361 }
362
363 return fib_info_hashfn_result(val);
364 }
365
366 /* no metrics, only nexthop id */
fib_find_info_nh(struct net * net,const struct fib_config * cfg)367 static struct fib_info *fib_find_info_nh(struct net *net,
368 const struct fib_config *cfg)
369 {
370 struct hlist_head *head;
371 struct fib_info *fi;
372 unsigned int hash;
373
374 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
375 cfg->fc_protocol, cfg->fc_scope,
376 (__force u32)cfg->fc_prefsrc,
377 cfg->fc_priority);
378 hash = fib_info_hashfn_result(hash);
379 head = &fib_info_hash[hash];
380
381 hlist_for_each_entry(fi, head, fib_hash) {
382 if (!net_eq(fi->fib_net, net))
383 continue;
384 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
385 continue;
386 if (cfg->fc_protocol == fi->fib_protocol &&
387 cfg->fc_scope == fi->fib_scope &&
388 cfg->fc_prefsrc == fi->fib_prefsrc &&
389 cfg->fc_priority == fi->fib_priority &&
390 cfg->fc_type == fi->fib_type &&
391 cfg->fc_table == fi->fib_tb_id &&
392 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
393 return fi;
394 }
395
396 return NULL;
397 }
398
fib_find_info(struct fib_info * nfi)399 static struct fib_info *fib_find_info(struct fib_info *nfi)
400 {
401 struct hlist_head *head;
402 struct fib_info *fi;
403 unsigned int hash;
404
405 hash = fib_info_hashfn(nfi);
406 head = &fib_info_hash[hash];
407
408 hlist_for_each_entry(fi, head, fib_hash) {
409 if (!net_eq(fi->fib_net, nfi->fib_net))
410 continue;
411 if (fi->fib_nhs != nfi->fib_nhs)
412 continue;
413 if (nfi->fib_protocol == fi->fib_protocol &&
414 nfi->fib_scope == fi->fib_scope &&
415 nfi->fib_prefsrc == fi->fib_prefsrc &&
416 nfi->fib_priority == fi->fib_priority &&
417 nfi->fib_type == fi->fib_type &&
418 memcmp(nfi->fib_metrics, fi->fib_metrics,
419 sizeof(u32) * RTAX_MAX) == 0 &&
420 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
421 nh_comp(fi, nfi) == 0)
422 return fi;
423 }
424
425 return NULL;
426 }
427
428 /* Check, that the gateway is already configured.
429 * Used only by redirect accept routine.
430 */
ip_fib_check_default(__be32 gw,struct net_device * dev)431 int ip_fib_check_default(__be32 gw, struct net_device *dev)
432 {
433 struct hlist_head *head;
434 struct fib_nh *nh;
435 unsigned int hash;
436
437 spin_lock(&fib_info_lock);
438
439 hash = fib_devindex_hashfn(dev->ifindex);
440 head = &fib_info_devhash[hash];
441 hlist_for_each_entry(nh, head, nh_hash) {
442 if (nh->fib_nh_dev == dev &&
443 nh->fib_nh_gw4 == gw &&
444 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
445 spin_unlock(&fib_info_lock);
446 return 0;
447 }
448 }
449
450 spin_unlock(&fib_info_lock);
451
452 return -1;
453 }
454
fib_nlmsg_size(struct fib_info * fi)455 size_t fib_nlmsg_size(struct fib_info *fi)
456 {
457 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
458 + nla_total_size(4) /* RTA_TABLE */
459 + nla_total_size(4) /* RTA_DST */
460 + nla_total_size(4) /* RTA_PRIORITY */
461 + nla_total_size(4) /* RTA_PREFSRC */
462 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
463 unsigned int nhs = fib_info_num_path(fi);
464
465 /* space for nested metrics */
466 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
467
468 if (fi->nh)
469 payload += nla_total_size(4); /* RTA_NH_ID */
470
471 if (nhs) {
472 size_t nh_encapsize = 0;
473 /* Also handles the special case nhs == 1 */
474
475 /* each nexthop is packed in an attribute */
476 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
477 unsigned int i;
478
479 /* may contain flow and gateway attribute */
480 nhsize += 2 * nla_total_size(4);
481
482 /* grab encap info */
483 for (i = 0; i < fib_info_num_path(fi); i++) {
484 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
485
486 if (nhc->nhc_lwtstate) {
487 /* RTA_ENCAP_TYPE */
488 nh_encapsize += lwtunnel_get_encap_size(
489 nhc->nhc_lwtstate);
490 /* RTA_ENCAP */
491 nh_encapsize += nla_total_size(2);
492 }
493 }
494
495 /* all nexthops are packed in a nested attribute */
496 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
497
498 }
499
500 return payload;
501 }
502
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)503 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
504 int dst_len, u32 tb_id, const struct nl_info *info,
505 unsigned int nlm_flags)
506 {
507 struct fib_rt_info fri;
508 struct sk_buff *skb;
509 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
510 int err = -ENOBUFS;
511
512 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
513 if (!skb)
514 goto errout;
515
516 fri.fi = fa->fa_info;
517 fri.tb_id = tb_id;
518 fri.dst = key;
519 fri.dst_len = dst_len;
520 fri.tos = fa->fa_tos;
521 fri.type = fa->fa_type;
522 fri.offload = fa->offload;
523 fri.trap = fa->trap;
524 fri.offload_failed = fa->offload_failed;
525 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
526 if (err < 0) {
527 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
528 WARN_ON(err == -EMSGSIZE);
529 kfree_skb(skb);
530 goto errout;
531 }
532 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
533 info->nlh, GFP_KERNEL);
534 return;
535 errout:
536 if (err < 0)
537 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
538 }
539
fib_detect_death(struct fib_info * fi,int order,struct fib_info ** last_resort,int * last_idx,int dflt)540 static int fib_detect_death(struct fib_info *fi, int order,
541 struct fib_info **last_resort, int *last_idx,
542 int dflt)
543 {
544 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
545 struct neighbour *n;
546 int state = NUD_NONE;
547
548 if (likely(nhc->nhc_gw_family == AF_INET))
549 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
550 else if (nhc->nhc_gw_family == AF_INET6)
551 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
552 nhc->nhc_dev);
553 else
554 n = NULL;
555
556 if (n) {
557 state = n->nud_state;
558 neigh_release(n);
559 } else {
560 return 0;
561 }
562 if (state == NUD_REACHABLE)
563 return 0;
564 if ((state & NUD_VALID) && order != dflt)
565 return 0;
566 if ((state & NUD_VALID) ||
567 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
568 *last_resort = fi;
569 *last_idx = order;
570 }
571 return 1;
572 }
573
fib_nh_common_init(struct net * net,struct fib_nh_common * nhc,struct nlattr * encap,u16 encap_type,void * cfg,gfp_t gfp_flags,struct netlink_ext_ack * extack)574 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
575 struct nlattr *encap, u16 encap_type,
576 void *cfg, gfp_t gfp_flags,
577 struct netlink_ext_ack *extack)
578 {
579 int err;
580
581 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
582 gfp_flags);
583 if (!nhc->nhc_pcpu_rth_output)
584 return -ENOMEM;
585
586 if (encap) {
587 struct lwtunnel_state *lwtstate;
588
589 if (encap_type == LWTUNNEL_ENCAP_NONE) {
590 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
591 err = -EINVAL;
592 goto lwt_failure;
593 }
594 err = lwtunnel_build_state(net, encap_type, encap,
595 nhc->nhc_family, cfg, &lwtstate,
596 extack);
597 if (err)
598 goto lwt_failure;
599
600 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
601 }
602
603 return 0;
604
605 lwt_failure:
606 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
607 nhc->nhc_pcpu_rth_output = NULL;
608 return err;
609 }
610 EXPORT_SYMBOL_GPL(fib_nh_common_init);
611
fib_nh_init(struct net * net,struct fib_nh * nh,struct fib_config * cfg,int nh_weight,struct netlink_ext_ack * extack)612 int fib_nh_init(struct net *net, struct fib_nh *nh,
613 struct fib_config *cfg, int nh_weight,
614 struct netlink_ext_ack *extack)
615 {
616 int err;
617
618 nh->fib_nh_family = AF_INET;
619
620 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
621 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
622 if (err)
623 return err;
624
625 nh->fib_nh_oif = cfg->fc_oif;
626 nh->fib_nh_gw_family = cfg->fc_gw_family;
627 if (cfg->fc_gw_family == AF_INET)
628 nh->fib_nh_gw4 = cfg->fc_gw4;
629 else if (cfg->fc_gw_family == AF_INET6)
630 nh->fib_nh_gw6 = cfg->fc_gw6;
631
632 nh->fib_nh_flags = cfg->fc_flags;
633
634 #ifdef CONFIG_IP_ROUTE_CLASSID
635 nh->nh_tclassid = cfg->fc_flow;
636 if (nh->nh_tclassid)
637 net->ipv4.fib_num_tclassid_users++;
638 #endif
639 #ifdef CONFIG_IP_ROUTE_MULTIPATH
640 nh->fib_nh_weight = nh_weight;
641 #endif
642 return 0;
643 }
644
645 #ifdef CONFIG_IP_ROUTE_MULTIPATH
646
fib_count_nexthops(struct rtnexthop * rtnh,int remaining,struct netlink_ext_ack * extack)647 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
648 struct netlink_ext_ack *extack)
649 {
650 int nhs = 0;
651
652 while (rtnh_ok(rtnh, remaining)) {
653 nhs++;
654 rtnh = rtnh_next(rtnh, &remaining);
655 }
656
657 /* leftover implies invalid nexthop configuration, discard it */
658 if (remaining > 0) {
659 NL_SET_ERR_MSG(extack,
660 "Invalid nexthop configuration - extra data after nexthops");
661 nhs = 0;
662 }
663
664 return nhs;
665 }
666
667 /* 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)668 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
669 int remaining, struct fib_config *cfg,
670 struct netlink_ext_ack *extack)
671 {
672 struct net *net = fi->fib_net;
673 struct fib_config fib_cfg;
674 struct fib_nh *nh;
675 int ret;
676
677 change_nexthops(fi) {
678 int attrlen;
679
680 memset(&fib_cfg, 0, sizeof(fib_cfg));
681
682 if (!rtnh_ok(rtnh, remaining)) {
683 NL_SET_ERR_MSG(extack,
684 "Invalid nexthop configuration - extra data after nexthop");
685 return -EINVAL;
686 }
687
688 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
689 NL_SET_ERR_MSG(extack,
690 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
691 return -EINVAL;
692 }
693
694 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
695 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
696
697 attrlen = rtnh_attrlen(rtnh);
698 if (attrlen > 0) {
699 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
700
701 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
702 nlav = nla_find(attrs, attrlen, RTA_VIA);
703 if (nla && nlav) {
704 NL_SET_ERR_MSG(extack,
705 "Nexthop configuration can not contain both GATEWAY and VIA");
706 return -EINVAL;
707 }
708 if (nla) {
709 fib_cfg.fc_gw4 = nla_get_in_addr(nla);
710 if (fib_cfg.fc_gw4)
711 fib_cfg.fc_gw_family = AF_INET;
712 } else if (nlav) {
713 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
714 if (ret)
715 goto errout;
716 }
717
718 nla = nla_find(attrs, attrlen, RTA_FLOW);
719 if (nla)
720 fib_cfg.fc_flow = nla_get_u32(nla);
721
722 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
723 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
724 if (nla)
725 fib_cfg.fc_encap_type = nla_get_u16(nla);
726 }
727
728 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
729 rtnh->rtnh_hops + 1, extack);
730 if (ret)
731 goto errout;
732
733 rtnh = rtnh_next(rtnh, &remaining);
734 } endfor_nexthops(fi);
735
736 ret = -EINVAL;
737 nh = fib_info_nh(fi, 0);
738 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
739 NL_SET_ERR_MSG(extack,
740 "Nexthop device index does not match RTA_OIF");
741 goto errout;
742 }
743 if (cfg->fc_gw_family) {
744 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
745 (cfg->fc_gw_family == AF_INET &&
746 nh->fib_nh_gw4 != cfg->fc_gw4) ||
747 (cfg->fc_gw_family == AF_INET6 &&
748 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
749 NL_SET_ERR_MSG(extack,
750 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
751 goto errout;
752 }
753 }
754 #ifdef CONFIG_IP_ROUTE_CLASSID
755 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
756 NL_SET_ERR_MSG(extack,
757 "Nexthop class id does not match RTA_FLOW");
758 goto errout;
759 }
760 #endif
761 ret = 0;
762 errout:
763 return ret;
764 }
765
766 /* only called when fib_nh is integrated into fib_info */
fib_rebalance(struct fib_info * fi)767 static void fib_rebalance(struct fib_info *fi)
768 {
769 int total;
770 int w;
771
772 if (fib_info_num_path(fi) < 2)
773 return;
774
775 total = 0;
776 for_nexthops(fi) {
777 if (nh->fib_nh_flags & RTNH_F_DEAD)
778 continue;
779
780 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
781 nh->fib_nh_flags & RTNH_F_LINKDOWN)
782 continue;
783
784 total += nh->fib_nh_weight;
785 } endfor_nexthops(fi);
786
787 w = 0;
788 change_nexthops(fi) {
789 int upper_bound;
790
791 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
792 upper_bound = -1;
793 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
794 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
795 upper_bound = -1;
796 } else {
797 w += nexthop_nh->fib_nh_weight;
798 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
799 total) - 1;
800 }
801
802 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
803 } endfor_nexthops(fi);
804 }
805 #else /* CONFIG_IP_ROUTE_MULTIPATH */
806
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)807 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
808 int remaining, struct fib_config *cfg,
809 struct netlink_ext_ack *extack)
810 {
811 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
812
813 return -EINVAL;
814 }
815
816 #define fib_rebalance(fi) do { } while (0)
817
818 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
819
fib_encap_match(struct net * net,u16 encap_type,struct nlattr * encap,const struct fib_nh * nh,const struct fib_config * cfg,struct netlink_ext_ack * extack)820 static int fib_encap_match(struct net *net, u16 encap_type,
821 struct nlattr *encap,
822 const struct fib_nh *nh,
823 const struct fib_config *cfg,
824 struct netlink_ext_ack *extack)
825 {
826 struct lwtunnel_state *lwtstate;
827 int ret, result = 0;
828
829 if (encap_type == LWTUNNEL_ENCAP_NONE)
830 return 0;
831
832 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
833 cfg, &lwtstate, extack);
834 if (!ret) {
835 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
836 lwtstate_free(lwtstate);
837 }
838
839 return result;
840 }
841
fib_nh_match(struct net * net,struct fib_config * cfg,struct fib_info * fi,struct netlink_ext_ack * extack)842 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
843 struct netlink_ext_ack *extack)
844 {
845 #ifdef CONFIG_IP_ROUTE_MULTIPATH
846 struct rtnexthop *rtnh;
847 int remaining;
848 #endif
849
850 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
851 return 1;
852
853 if (cfg->fc_nh_id) {
854 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
855 return 0;
856 return 1;
857 }
858
859 if (cfg->fc_oif || cfg->fc_gw_family) {
860 struct fib_nh *nh = fib_info_nh(fi, 0);
861
862 if (cfg->fc_encap) {
863 if (fib_encap_match(net, cfg->fc_encap_type,
864 cfg->fc_encap, nh, cfg, extack))
865 return 1;
866 }
867 #ifdef CONFIG_IP_ROUTE_CLASSID
868 if (cfg->fc_flow &&
869 cfg->fc_flow != nh->nh_tclassid)
870 return 1;
871 #endif
872 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
873 (cfg->fc_gw_family &&
874 cfg->fc_gw_family != nh->fib_nh_gw_family))
875 return 1;
876
877 if (cfg->fc_gw_family == AF_INET &&
878 cfg->fc_gw4 != nh->fib_nh_gw4)
879 return 1;
880
881 if (cfg->fc_gw_family == AF_INET6 &&
882 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
883 return 1;
884
885 return 0;
886 }
887
888 #ifdef CONFIG_IP_ROUTE_MULTIPATH
889 if (!cfg->fc_mp)
890 return 0;
891
892 rtnh = cfg->fc_mp;
893 remaining = cfg->fc_mp_len;
894
895 for_nexthops(fi) {
896 int attrlen;
897
898 if (!rtnh_ok(rtnh, remaining))
899 return -EINVAL;
900
901 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
902 return 1;
903
904 attrlen = rtnh_attrlen(rtnh);
905 if (attrlen > 0) {
906 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
907
908 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
909 nlav = nla_find(attrs, attrlen, RTA_VIA);
910 if (nla && nlav) {
911 NL_SET_ERR_MSG(extack,
912 "Nexthop configuration can not contain both GATEWAY and VIA");
913 return -EINVAL;
914 }
915
916 if (nla) {
917 if (nh->fib_nh_gw_family != AF_INET ||
918 nla_get_in_addr(nla) != nh->fib_nh_gw4)
919 return 1;
920 } else if (nlav) {
921 struct fib_config cfg2;
922 int err;
923
924 err = fib_gw_from_via(&cfg2, nlav, extack);
925 if (err)
926 return err;
927
928 switch (nh->fib_nh_gw_family) {
929 case AF_INET:
930 if (cfg2.fc_gw_family != AF_INET ||
931 cfg2.fc_gw4 != nh->fib_nh_gw4)
932 return 1;
933 break;
934 case AF_INET6:
935 if (cfg2.fc_gw_family != AF_INET6 ||
936 ipv6_addr_cmp(&cfg2.fc_gw6,
937 &nh->fib_nh_gw6))
938 return 1;
939 break;
940 }
941 }
942
943 #ifdef CONFIG_IP_ROUTE_CLASSID
944 nla = nla_find(attrs, attrlen, RTA_FLOW);
945 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
946 return 1;
947 #endif
948 }
949
950 rtnh = rtnh_next(rtnh, &remaining);
951 } endfor_nexthops(fi);
952 #endif
953 return 0;
954 }
955
fib_metrics_match(struct fib_config * cfg,struct fib_info * fi)956 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
957 {
958 struct nlattr *nla;
959 int remaining;
960
961 if (!cfg->fc_mx)
962 return true;
963
964 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
965 int type = nla_type(nla);
966 u32 fi_val, val;
967
968 if (!type)
969 continue;
970 if (type > RTAX_MAX)
971 return false;
972
973 if (type == RTAX_CC_ALGO) {
974 char tmp[TCP_CA_NAME_MAX];
975 bool ecn_ca = false;
976
977 nla_strscpy(tmp, nla, sizeof(tmp));
978 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
979 } else {
980 if (nla_len(nla) != sizeof(u32))
981 return false;
982 val = nla_get_u32(nla);
983 }
984
985 fi_val = fi->fib_metrics->metrics[type - 1];
986 if (type == RTAX_FEATURES)
987 fi_val &= ~DST_FEATURE_ECN_CA;
988
989 if (fi_val != val)
990 return false;
991 }
992
993 return true;
994 }
995
fib_check_nh_v6_gw(struct net * net,struct fib_nh * nh,u32 table,struct netlink_ext_ack * extack)996 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
997 u32 table, struct netlink_ext_ack *extack)
998 {
999 struct fib6_config cfg = {
1000 .fc_table = table,
1001 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1002 .fc_ifindex = nh->fib_nh_oif,
1003 .fc_gateway = nh->fib_nh_gw6,
1004 };
1005 struct fib6_nh fib6_nh = {};
1006 int err;
1007
1008 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1009 if (!err) {
1010 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1011 dev_hold(nh->fib_nh_dev);
1012 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1013 nh->fib_nh_scope = RT_SCOPE_LINK;
1014
1015 ipv6_stub->fib6_nh_release(&fib6_nh);
1016 }
1017
1018 return err;
1019 }
1020
1021 /*
1022 * Picture
1023 * -------
1024 *
1025 * Semantics of nexthop is very messy by historical reasons.
1026 * We have to take into account, that:
1027 * a) gateway can be actually local interface address,
1028 * so that gatewayed route is direct.
1029 * b) gateway must be on-link address, possibly
1030 * described not by an ifaddr, but also by a direct route.
1031 * c) If both gateway and interface are specified, they should not
1032 * contradict.
1033 * d) If we use tunnel routes, gateway could be not on-link.
1034 *
1035 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1036 * results in pretty ugly and hairy code with obscure logic.
1037 *
1038 * I chose to generalized it instead, so that the size
1039 * of code does not increase practically, but it becomes
1040 * much more general.
1041 * Every prefix is assigned a "scope" value: "host" is local address,
1042 * "link" is direct route,
1043 * [ ... "site" ... "interior" ... ]
1044 * and "universe" is true gateway route with global meaning.
1045 *
1046 * Every prefix refers to a set of "nexthop"s (gw, oif),
1047 * where gw must have narrower scope. This recursion stops
1048 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1049 * which means that gw is forced to be on link.
1050 *
1051 * Code is still hairy, but now it is apparently logically
1052 * consistent and very flexible. F.e. as by-product it allows
1053 * to co-exists in peace independent exterior and interior
1054 * routing processes.
1055 *
1056 * Normally it looks as following.
1057 *
1058 * {universe prefix} -> (gw, oif) [scope link]
1059 * |
1060 * |-> {link prefix} -> (gw, oif) [scope local]
1061 * |
1062 * |-> {local prefix} (terminal node)
1063 */
fib_check_nh_v4_gw(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1064 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1065 u8 scope, struct netlink_ext_ack *extack)
1066 {
1067 struct net_device *dev;
1068 struct fib_result res;
1069 int err = 0;
1070
1071 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1072 unsigned int addr_type;
1073
1074 if (scope >= RT_SCOPE_LINK) {
1075 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1076 return -EINVAL;
1077 }
1078 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1079 if (!dev) {
1080 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1081 return -ENODEV;
1082 }
1083 if (!(dev->flags & IFF_UP)) {
1084 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1085 return -ENETDOWN;
1086 }
1087 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1088 if (addr_type != RTN_UNICAST) {
1089 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1090 return -EINVAL;
1091 }
1092 if (!netif_carrier_ok(dev))
1093 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1094 nh->fib_nh_dev = dev;
1095 dev_hold(dev);
1096 nh->fib_nh_scope = RT_SCOPE_LINK;
1097 return 0;
1098 }
1099 rcu_read_lock();
1100 {
1101 struct fib_table *tbl = NULL;
1102 struct flowi4 fl4 = {
1103 .daddr = nh->fib_nh_gw4,
1104 .flowi4_scope = scope + 1,
1105 .flowi4_oif = nh->fib_nh_oif,
1106 .flowi4_iif = LOOPBACK_IFINDEX,
1107 };
1108
1109 /* It is not necessary, but requires a bit of thinking */
1110 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1111 fl4.flowi4_scope = RT_SCOPE_LINK;
1112
1113 if (table && table != RT_TABLE_MAIN)
1114 tbl = fib_get_table(net, table);
1115
1116 if (tbl)
1117 err = fib_table_lookup(tbl, &fl4, &res,
1118 FIB_LOOKUP_IGNORE_LINKSTATE |
1119 FIB_LOOKUP_NOREF);
1120
1121 /* on error or if no table given do full lookup. This
1122 * is needed for example when nexthops are in the local
1123 * table rather than the given table
1124 */
1125 if (!tbl || err) {
1126 err = fib_lookup(net, &fl4, &res,
1127 FIB_LOOKUP_IGNORE_LINKSTATE);
1128 }
1129
1130 if (err) {
1131 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1132 goto out;
1133 }
1134 }
1135
1136 err = -EINVAL;
1137 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1138 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1139 goto out;
1140 }
1141 nh->fib_nh_scope = res.scope;
1142 nh->fib_nh_oif = FIB_RES_OIF(res);
1143 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1144 if (!dev) {
1145 NL_SET_ERR_MSG(extack,
1146 "No egress device for nexthop gateway");
1147 goto out;
1148 }
1149 dev_hold(dev);
1150 if (!netif_carrier_ok(dev))
1151 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1152 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1153 out:
1154 rcu_read_unlock();
1155 return err;
1156 }
1157
fib_check_nh_nongw(struct net * net,struct fib_nh * nh,struct netlink_ext_ack * extack)1158 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1159 struct netlink_ext_ack *extack)
1160 {
1161 struct in_device *in_dev;
1162 int err;
1163
1164 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1165 NL_SET_ERR_MSG(extack,
1166 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1167 return -EINVAL;
1168 }
1169
1170 rcu_read_lock();
1171
1172 err = -ENODEV;
1173 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1174 if (!in_dev)
1175 goto out;
1176 err = -ENETDOWN;
1177 if (!(in_dev->dev->flags & IFF_UP)) {
1178 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1179 goto out;
1180 }
1181
1182 nh->fib_nh_dev = in_dev->dev;
1183 dev_hold(nh->fib_nh_dev);
1184 nh->fib_nh_scope = RT_SCOPE_HOST;
1185 if (!netif_carrier_ok(nh->fib_nh_dev))
1186 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1187 err = 0;
1188 out:
1189 rcu_read_unlock();
1190 return err;
1191 }
1192
fib_check_nh(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1193 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1194 struct netlink_ext_ack *extack)
1195 {
1196 int err;
1197
1198 if (nh->fib_nh_gw_family == AF_INET)
1199 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1200 else if (nh->fib_nh_gw_family == AF_INET6)
1201 err = fib_check_nh_v6_gw(net, nh, table, extack);
1202 else
1203 err = fib_check_nh_nongw(net, nh, extack);
1204
1205 return err;
1206 }
1207
fib_laddr_hashfn(__be32 val)1208 static inline unsigned int fib_laddr_hashfn(__be32 val)
1209 {
1210 unsigned int mask = (fib_info_hash_size - 1);
1211
1212 return ((__force u32)val ^
1213 ((__force u32)val >> 7) ^
1214 ((__force u32)val >> 14)) & mask;
1215 }
1216
fib_info_hash_alloc(int bytes)1217 static struct hlist_head *fib_info_hash_alloc(int bytes)
1218 {
1219 if (bytes <= PAGE_SIZE)
1220 return kzalloc(bytes, GFP_KERNEL);
1221 else
1222 return (struct hlist_head *)
1223 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1224 get_order(bytes));
1225 }
1226
fib_info_hash_free(struct hlist_head * hash,int bytes)1227 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1228 {
1229 if (!hash)
1230 return;
1231
1232 if (bytes <= PAGE_SIZE)
1233 kfree(hash);
1234 else
1235 free_pages((unsigned long) hash, get_order(bytes));
1236 }
1237
fib_info_hash_move(struct hlist_head * new_info_hash,struct hlist_head * new_laddrhash,unsigned int new_size)1238 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1239 struct hlist_head *new_laddrhash,
1240 unsigned int new_size)
1241 {
1242 struct hlist_head *old_info_hash, *old_laddrhash;
1243 unsigned int old_size = fib_info_hash_size;
1244 unsigned int i, bytes;
1245
1246 spin_lock_bh(&fib_info_lock);
1247 old_info_hash = fib_info_hash;
1248 old_laddrhash = fib_info_laddrhash;
1249 fib_info_hash_size = new_size;
1250
1251 for (i = 0; i < old_size; i++) {
1252 struct hlist_head *head = &fib_info_hash[i];
1253 struct hlist_node *n;
1254 struct fib_info *fi;
1255
1256 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1257 struct hlist_head *dest;
1258 unsigned int new_hash;
1259
1260 new_hash = fib_info_hashfn(fi);
1261 dest = &new_info_hash[new_hash];
1262 hlist_add_head(&fi->fib_hash, dest);
1263 }
1264 }
1265 fib_info_hash = new_info_hash;
1266
1267 for (i = 0; i < old_size; i++) {
1268 struct hlist_head *lhead = &fib_info_laddrhash[i];
1269 struct hlist_node *n;
1270 struct fib_info *fi;
1271
1272 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1273 struct hlist_head *ldest;
1274 unsigned int new_hash;
1275
1276 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1277 ldest = &new_laddrhash[new_hash];
1278 hlist_add_head(&fi->fib_lhash, ldest);
1279 }
1280 }
1281 fib_info_laddrhash = new_laddrhash;
1282
1283 spin_unlock_bh(&fib_info_lock);
1284
1285 bytes = old_size * sizeof(struct hlist_head *);
1286 fib_info_hash_free(old_info_hash, bytes);
1287 fib_info_hash_free(old_laddrhash, bytes);
1288 }
1289
fib_info_update_nhc_saddr(struct net * net,struct fib_nh_common * nhc,unsigned char scope)1290 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1291 unsigned char scope)
1292 {
1293 struct fib_nh *nh;
1294
1295 if (nhc->nhc_family != AF_INET)
1296 return inet_select_addr(nhc->nhc_dev, 0, scope);
1297
1298 nh = container_of(nhc, struct fib_nh, nh_common);
1299 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1300 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1301
1302 return nh->nh_saddr;
1303 }
1304
fib_result_prefsrc(struct net * net,struct fib_result * res)1305 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1306 {
1307 struct fib_nh_common *nhc = res->nhc;
1308
1309 if (res->fi->fib_prefsrc)
1310 return res->fi->fib_prefsrc;
1311
1312 if (nhc->nhc_family == AF_INET) {
1313 struct fib_nh *nh;
1314
1315 nh = container_of(nhc, struct fib_nh, nh_common);
1316 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1317 return nh->nh_saddr;
1318 }
1319
1320 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1321 }
1322
fib_valid_prefsrc(struct fib_config * cfg,__be32 fib_prefsrc)1323 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1324 {
1325 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1326 fib_prefsrc != cfg->fc_dst) {
1327 u32 tb_id = cfg->fc_table;
1328 int rc;
1329
1330 if (tb_id == RT_TABLE_MAIN)
1331 tb_id = RT_TABLE_LOCAL;
1332
1333 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1334 fib_prefsrc, tb_id);
1335
1336 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1337 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1338 fib_prefsrc, RT_TABLE_LOCAL);
1339 }
1340
1341 if (rc != RTN_LOCAL)
1342 return false;
1343 }
1344 return true;
1345 }
1346
fib_create_info(struct fib_config * cfg,struct netlink_ext_ack * extack)1347 struct fib_info *fib_create_info(struct fib_config *cfg,
1348 struct netlink_ext_ack *extack)
1349 {
1350 int err;
1351 struct fib_info *fi = NULL;
1352 struct nexthop *nh = NULL;
1353 struct fib_info *ofi;
1354 int nhs = 1;
1355 struct net *net = cfg->fc_nlinfo.nl_net;
1356
1357 if (cfg->fc_type > RTN_MAX)
1358 goto err_inval;
1359
1360 /* Fast check to catch the most weird cases */
1361 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1362 NL_SET_ERR_MSG(extack, "Invalid scope");
1363 goto err_inval;
1364 }
1365
1366 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1367 NL_SET_ERR_MSG(extack,
1368 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1369 goto err_inval;
1370 }
1371
1372 if (cfg->fc_nh_id) {
1373 if (!cfg->fc_mx) {
1374 fi = fib_find_info_nh(net, cfg);
1375 if (fi) {
1376 fi->fib_treeref++;
1377 return fi;
1378 }
1379 }
1380
1381 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1382 if (!nh) {
1383 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1384 goto err_inval;
1385 }
1386 nhs = 0;
1387 }
1388
1389 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1390 if (cfg->fc_mp) {
1391 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1392 if (nhs == 0)
1393 goto err_inval;
1394 }
1395 #endif
1396
1397 err = -ENOBUFS;
1398 if (fib_info_cnt >= fib_info_hash_size) {
1399 unsigned int new_size = fib_info_hash_size << 1;
1400 struct hlist_head *new_info_hash;
1401 struct hlist_head *new_laddrhash;
1402 unsigned int bytes;
1403
1404 if (!new_size)
1405 new_size = 16;
1406 bytes = new_size * sizeof(struct hlist_head *);
1407 new_info_hash = fib_info_hash_alloc(bytes);
1408 new_laddrhash = fib_info_hash_alloc(bytes);
1409 if (!new_info_hash || !new_laddrhash) {
1410 fib_info_hash_free(new_info_hash, bytes);
1411 fib_info_hash_free(new_laddrhash, bytes);
1412 } else
1413 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1414
1415 if (!fib_info_hash_size)
1416 goto failure;
1417 }
1418
1419 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1420 if (!fi)
1421 goto failure;
1422 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1423 cfg->fc_mx_len, extack);
1424 if (IS_ERR(fi->fib_metrics)) {
1425 err = PTR_ERR(fi->fib_metrics);
1426 kfree(fi);
1427 return ERR_PTR(err);
1428 }
1429
1430 fib_info_cnt++;
1431 fi->fib_net = net;
1432 fi->fib_protocol = cfg->fc_protocol;
1433 fi->fib_scope = cfg->fc_scope;
1434 fi->fib_flags = cfg->fc_flags;
1435 fi->fib_priority = cfg->fc_priority;
1436 fi->fib_prefsrc = cfg->fc_prefsrc;
1437 fi->fib_type = cfg->fc_type;
1438 fi->fib_tb_id = cfg->fc_table;
1439
1440 fi->fib_nhs = nhs;
1441 if (nh) {
1442 if (!nexthop_get(nh)) {
1443 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1444 err = -EINVAL;
1445 } else {
1446 err = 0;
1447 fi->nh = nh;
1448 }
1449 } else {
1450 change_nexthops(fi) {
1451 nexthop_nh->nh_parent = fi;
1452 } endfor_nexthops(fi)
1453
1454 if (cfg->fc_mp)
1455 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1456 extack);
1457 else
1458 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1459 }
1460
1461 if (err != 0)
1462 goto failure;
1463
1464 if (fib_props[cfg->fc_type].error) {
1465 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1466 NL_SET_ERR_MSG(extack,
1467 "Gateway, device and multipath can not be specified for this route type");
1468 goto err_inval;
1469 }
1470 goto link_it;
1471 } else {
1472 switch (cfg->fc_type) {
1473 case RTN_UNICAST:
1474 case RTN_LOCAL:
1475 case RTN_BROADCAST:
1476 case RTN_ANYCAST:
1477 case RTN_MULTICAST:
1478 break;
1479 default:
1480 NL_SET_ERR_MSG(extack, "Invalid route type");
1481 goto err_inval;
1482 }
1483 }
1484
1485 if (cfg->fc_scope > RT_SCOPE_HOST) {
1486 NL_SET_ERR_MSG(extack, "Invalid scope");
1487 goto err_inval;
1488 }
1489
1490 if (fi->nh) {
1491 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1492 if (err)
1493 goto failure;
1494 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1495 struct fib_nh *nh = fi->fib_nh;
1496
1497 /* Local address is added. */
1498 if (nhs != 1) {
1499 NL_SET_ERR_MSG(extack,
1500 "Route with host scope can not have multiple nexthops");
1501 goto err_inval;
1502 }
1503 if (nh->fib_nh_gw_family) {
1504 NL_SET_ERR_MSG(extack,
1505 "Route with host scope can not have a gateway");
1506 goto err_inval;
1507 }
1508 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1509 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1510 err = -ENODEV;
1511 if (!nh->fib_nh_dev)
1512 goto failure;
1513 } else {
1514 int linkdown = 0;
1515
1516 change_nexthops(fi) {
1517 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1518 cfg->fc_table, cfg->fc_scope,
1519 extack);
1520 if (err != 0)
1521 goto failure;
1522 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1523 linkdown++;
1524 } endfor_nexthops(fi)
1525 if (linkdown == fi->fib_nhs)
1526 fi->fib_flags |= RTNH_F_LINKDOWN;
1527 }
1528
1529 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1530 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1531 goto err_inval;
1532 }
1533
1534 if (!fi->nh) {
1535 change_nexthops(fi) {
1536 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1537 fi->fib_scope);
1538 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1539 fi->fib_nh_is_v6 = true;
1540 } endfor_nexthops(fi)
1541
1542 fib_rebalance(fi);
1543 }
1544
1545 link_it:
1546 ofi = fib_find_info(fi);
1547 if (ofi) {
1548 fi->fib_dead = 1;
1549 free_fib_info(fi);
1550 ofi->fib_treeref++;
1551 return ofi;
1552 }
1553
1554 fi->fib_treeref++;
1555 refcount_set(&fi->fib_clntref, 1);
1556 spin_lock_bh(&fib_info_lock);
1557 hlist_add_head(&fi->fib_hash,
1558 &fib_info_hash[fib_info_hashfn(fi)]);
1559 if (fi->fib_prefsrc) {
1560 struct hlist_head *head;
1561
1562 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1563 hlist_add_head(&fi->fib_lhash, head);
1564 }
1565 if (fi->nh) {
1566 list_add(&fi->nh_list, &nh->fi_list);
1567 } else {
1568 change_nexthops(fi) {
1569 struct hlist_head *head;
1570 unsigned int hash;
1571
1572 if (!nexthop_nh->fib_nh_dev)
1573 continue;
1574 hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
1575 head = &fib_info_devhash[hash];
1576 hlist_add_head(&nexthop_nh->nh_hash, head);
1577 } endfor_nexthops(fi)
1578 }
1579 spin_unlock_bh(&fib_info_lock);
1580 return fi;
1581
1582 err_inval:
1583 err = -EINVAL;
1584
1585 failure:
1586 if (fi) {
1587 fi->fib_dead = 1;
1588 free_fib_info(fi);
1589 }
1590
1591 return ERR_PTR(err);
1592 }
1593
fib_nexthop_info(struct sk_buff * skb,const struct fib_nh_common * nhc,u8 rt_family,unsigned char * flags,bool skip_oif)1594 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1595 u8 rt_family, unsigned char *flags, bool skip_oif)
1596 {
1597 if (nhc->nhc_flags & RTNH_F_DEAD)
1598 *flags |= RTNH_F_DEAD;
1599
1600 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1601 *flags |= RTNH_F_LINKDOWN;
1602
1603 rcu_read_lock();
1604 switch (nhc->nhc_family) {
1605 case AF_INET:
1606 if (ip_ignore_linkdown(nhc->nhc_dev))
1607 *flags |= RTNH_F_DEAD;
1608 break;
1609 case AF_INET6:
1610 if (ip6_ignore_linkdown(nhc->nhc_dev))
1611 *flags |= RTNH_F_DEAD;
1612 break;
1613 }
1614 rcu_read_unlock();
1615 }
1616
1617 switch (nhc->nhc_gw_family) {
1618 case AF_INET:
1619 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1620 goto nla_put_failure;
1621 break;
1622 case AF_INET6:
1623 /* if gateway family does not match nexthop family
1624 * gateway is encoded as RTA_VIA
1625 */
1626 if (rt_family != nhc->nhc_gw_family) {
1627 int alen = sizeof(struct in6_addr);
1628 struct nlattr *nla;
1629 struct rtvia *via;
1630
1631 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1632 if (!nla)
1633 goto nla_put_failure;
1634
1635 via = nla_data(nla);
1636 via->rtvia_family = AF_INET6;
1637 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1638 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1639 &nhc->nhc_gw.ipv6) < 0) {
1640 goto nla_put_failure;
1641 }
1642 break;
1643 }
1644
1645 *flags |= (nhc->nhc_flags &
1646 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1647
1648 if (!skip_oif && nhc->nhc_dev &&
1649 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1650 goto nla_put_failure;
1651
1652 if (nhc->nhc_lwtstate &&
1653 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1654 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1655 goto nla_put_failure;
1656
1657 return 0;
1658
1659 nla_put_failure:
1660 return -EMSGSIZE;
1661 }
1662 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1663
1664 #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)1665 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1666 int nh_weight, u8 rt_family)
1667 {
1668 const struct net_device *dev = nhc->nhc_dev;
1669 struct rtnexthop *rtnh;
1670 unsigned char flags = 0;
1671
1672 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1673 if (!rtnh)
1674 goto nla_put_failure;
1675
1676 rtnh->rtnh_hops = nh_weight - 1;
1677 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1678
1679 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1680 goto nla_put_failure;
1681
1682 rtnh->rtnh_flags = flags;
1683
1684 /* length of rtnetlink header + attributes */
1685 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1686
1687 return 0;
1688
1689 nla_put_failure:
1690 return -EMSGSIZE;
1691 }
1692 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1693 #endif
1694
1695 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1696 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1697 {
1698 struct nlattr *mp;
1699
1700 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1701 if (!mp)
1702 goto nla_put_failure;
1703
1704 if (unlikely(fi->nh)) {
1705 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1706 goto nla_put_failure;
1707 goto mp_end;
1708 }
1709
1710 for_nexthops(fi) {
1711 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1712 AF_INET) < 0)
1713 goto nla_put_failure;
1714 #ifdef CONFIG_IP_ROUTE_CLASSID
1715 if (nh->nh_tclassid &&
1716 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1717 goto nla_put_failure;
1718 #endif
1719 } endfor_nexthops(fi);
1720
1721 mp_end:
1722 nla_nest_end(skb, mp);
1723
1724 return 0;
1725
1726 nla_put_failure:
1727 return -EMSGSIZE;
1728 }
1729 #else
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1730 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1731 {
1732 return 0;
1733 }
1734 #endif
1735
fib_dump_info(struct sk_buff * skb,u32 portid,u32 seq,int event,const struct fib_rt_info * fri,unsigned int flags)1736 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1737 const struct fib_rt_info *fri, unsigned int flags)
1738 {
1739 unsigned int nhs = fib_info_num_path(fri->fi);
1740 struct fib_info *fi = fri->fi;
1741 u32 tb_id = fri->tb_id;
1742 struct nlmsghdr *nlh;
1743 struct rtmsg *rtm;
1744
1745 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1746 if (!nlh)
1747 return -EMSGSIZE;
1748
1749 rtm = nlmsg_data(nlh);
1750 rtm->rtm_family = AF_INET;
1751 rtm->rtm_dst_len = fri->dst_len;
1752 rtm->rtm_src_len = 0;
1753 rtm->rtm_tos = fri->tos;
1754 if (tb_id < 256)
1755 rtm->rtm_table = tb_id;
1756 else
1757 rtm->rtm_table = RT_TABLE_COMPAT;
1758 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1759 goto nla_put_failure;
1760 rtm->rtm_type = fri->type;
1761 rtm->rtm_flags = fi->fib_flags;
1762 rtm->rtm_scope = fi->fib_scope;
1763 rtm->rtm_protocol = fi->fib_protocol;
1764
1765 if (rtm->rtm_dst_len &&
1766 nla_put_in_addr(skb, RTA_DST, fri->dst))
1767 goto nla_put_failure;
1768 if (fi->fib_priority &&
1769 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1770 goto nla_put_failure;
1771 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1772 goto nla_put_failure;
1773
1774 if (fi->fib_prefsrc &&
1775 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1776 goto nla_put_failure;
1777
1778 if (fi->nh) {
1779 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1780 goto nla_put_failure;
1781 if (nexthop_is_blackhole(fi->nh))
1782 rtm->rtm_type = RTN_BLACKHOLE;
1783 if (!fi->fib_net->ipv4.sysctl_nexthop_compat_mode)
1784 goto offload;
1785 }
1786
1787 if (nhs == 1) {
1788 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1789 unsigned char flags = 0;
1790
1791 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1792 goto nla_put_failure;
1793
1794 rtm->rtm_flags = flags;
1795 #ifdef CONFIG_IP_ROUTE_CLASSID
1796 if (nhc->nhc_family == AF_INET) {
1797 struct fib_nh *nh;
1798
1799 nh = container_of(nhc, struct fib_nh, nh_common);
1800 if (nh->nh_tclassid &&
1801 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1802 goto nla_put_failure;
1803 }
1804 #endif
1805 } else {
1806 if (fib_add_multipath(skb, fi) < 0)
1807 goto nla_put_failure;
1808 }
1809
1810 offload:
1811 if (fri->offload)
1812 rtm->rtm_flags |= RTM_F_OFFLOAD;
1813 if (fri->trap)
1814 rtm->rtm_flags |= RTM_F_TRAP;
1815 if (fri->offload_failed)
1816 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1817
1818 nlmsg_end(skb, nlh);
1819 return 0;
1820
1821 nla_put_failure:
1822 nlmsg_cancel(skb, nlh);
1823 return -EMSGSIZE;
1824 }
1825
1826 /*
1827 * Update FIB if:
1828 * - local address disappeared -> we must delete all the entries
1829 * referring to it.
1830 * - device went down -> we must shutdown all nexthops going via it.
1831 */
fib_sync_down_addr(struct net_device * dev,__be32 local)1832 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1833 {
1834 int ret = 0;
1835 unsigned int hash = fib_laddr_hashfn(local);
1836 struct hlist_head *head = &fib_info_laddrhash[hash];
1837 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1838 struct net *net = dev_net(dev);
1839 struct fib_info *fi;
1840
1841 if (!fib_info_laddrhash || local == 0)
1842 return 0;
1843
1844 hlist_for_each_entry(fi, head, fib_lhash) {
1845 if (!net_eq(fi->fib_net, net) ||
1846 fi->fib_tb_id != tb_id)
1847 continue;
1848 if (fi->fib_prefsrc == local) {
1849 fi->fib_flags |= RTNH_F_DEAD;
1850 ret++;
1851 }
1852 }
1853 return ret;
1854 }
1855
call_fib_nh_notifiers(struct fib_nh * nh,enum fib_event_type event_type)1856 static int call_fib_nh_notifiers(struct fib_nh *nh,
1857 enum fib_event_type event_type)
1858 {
1859 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1860 struct fib_nh_notifier_info info = {
1861 .fib_nh = nh,
1862 };
1863
1864 switch (event_type) {
1865 case FIB_EVENT_NH_ADD:
1866 if (nh->fib_nh_flags & RTNH_F_DEAD)
1867 break;
1868 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1869 break;
1870 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1871 &info.info);
1872 case FIB_EVENT_NH_DEL:
1873 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1874 (nh->fib_nh_flags & RTNH_F_DEAD))
1875 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1876 event_type, &info.info);
1877 default:
1878 break;
1879 }
1880
1881 return NOTIFY_DONE;
1882 }
1883
1884 /* Update the PMTU of exceptions when:
1885 * - the new MTU of the first hop becomes smaller than the PMTU
1886 * - the old MTU was the same as the PMTU, and it limited discovery of
1887 * larger MTUs on the path. With that limit raised, we can now
1888 * discover larger MTUs
1889 * A special case is locked exceptions, for which the PMTU is smaller
1890 * than the minimal accepted PMTU:
1891 * - if the new MTU is greater than the PMTU, don't make any change
1892 * - otherwise, unlock and set PMTU
1893 */
fib_nhc_update_mtu(struct fib_nh_common * nhc,u32 new,u32 orig)1894 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1895 {
1896 struct fnhe_hash_bucket *bucket;
1897 int i;
1898
1899 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1900 if (!bucket)
1901 return;
1902
1903 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1904 struct fib_nh_exception *fnhe;
1905
1906 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1907 fnhe;
1908 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1909 if (fnhe->fnhe_mtu_locked) {
1910 if (new <= fnhe->fnhe_pmtu) {
1911 fnhe->fnhe_pmtu = new;
1912 fnhe->fnhe_mtu_locked = false;
1913 }
1914 } else if (new < fnhe->fnhe_pmtu ||
1915 orig == fnhe->fnhe_pmtu) {
1916 fnhe->fnhe_pmtu = new;
1917 }
1918 }
1919 }
1920 }
1921
fib_sync_mtu(struct net_device * dev,u32 orig_mtu)1922 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1923 {
1924 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1925 struct hlist_head *head = &fib_info_devhash[hash];
1926 struct fib_nh *nh;
1927
1928 hlist_for_each_entry(nh, head, nh_hash) {
1929 if (nh->fib_nh_dev == dev)
1930 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1931 }
1932 }
1933
1934 /* Event force Flags Description
1935 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1936 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1937 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1938 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1939 *
1940 * only used when fib_nh is built into fib_info
1941 */
fib_sync_down_dev(struct net_device * dev,unsigned long event,bool force)1942 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1943 {
1944 int ret = 0;
1945 int scope = RT_SCOPE_NOWHERE;
1946 struct fib_info *prev_fi = NULL;
1947 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1948 struct hlist_head *head = &fib_info_devhash[hash];
1949 struct fib_nh *nh;
1950
1951 if (force)
1952 scope = -1;
1953
1954 hlist_for_each_entry(nh, head, nh_hash) {
1955 struct fib_info *fi = nh->nh_parent;
1956 int dead;
1957
1958 BUG_ON(!fi->fib_nhs);
1959 if (nh->fib_nh_dev != dev || fi == prev_fi)
1960 continue;
1961 prev_fi = fi;
1962 dead = 0;
1963 change_nexthops(fi) {
1964 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1965 dead++;
1966 else if (nexthop_nh->fib_nh_dev == dev &&
1967 nexthop_nh->fib_nh_scope != scope) {
1968 switch (event) {
1969 case NETDEV_DOWN:
1970 case NETDEV_UNREGISTER:
1971 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1972 fallthrough;
1973 case NETDEV_CHANGE:
1974 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1975 break;
1976 }
1977 call_fib_nh_notifiers(nexthop_nh,
1978 FIB_EVENT_NH_DEL);
1979 dead++;
1980 }
1981 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1982 if (event == NETDEV_UNREGISTER &&
1983 nexthop_nh->fib_nh_dev == dev) {
1984 dead = fi->fib_nhs;
1985 break;
1986 }
1987 #endif
1988 } endfor_nexthops(fi)
1989 if (dead == fi->fib_nhs) {
1990 switch (event) {
1991 case NETDEV_DOWN:
1992 case NETDEV_UNREGISTER:
1993 fi->fib_flags |= RTNH_F_DEAD;
1994 fallthrough;
1995 case NETDEV_CHANGE:
1996 fi->fib_flags |= RTNH_F_LINKDOWN;
1997 break;
1998 }
1999 ret++;
2000 }
2001
2002 fib_rebalance(fi);
2003 }
2004
2005 return ret;
2006 }
2007
2008 /* Must be invoked inside of an RCU protected region. */
fib_select_default(const struct flowi4 * flp,struct fib_result * res)2009 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2010 {
2011 struct fib_info *fi = NULL, *last_resort = NULL;
2012 struct hlist_head *fa_head = res->fa_head;
2013 struct fib_table *tb = res->table;
2014 u8 slen = 32 - res->prefixlen;
2015 int order = -1, last_idx = -1;
2016 struct fib_alias *fa, *fa1 = NULL;
2017 u32 last_prio = res->fi->fib_priority;
2018 u8 last_tos = 0;
2019
2020 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2021 struct fib_info *next_fi = fa->fa_info;
2022 struct fib_nh_common *nhc;
2023
2024 if (fa->fa_slen != slen)
2025 continue;
2026 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2027 continue;
2028 if (fa->tb_id != tb->tb_id)
2029 continue;
2030 if (next_fi->fib_priority > last_prio &&
2031 fa->fa_tos == last_tos) {
2032 if (last_tos)
2033 continue;
2034 break;
2035 }
2036 if (next_fi->fib_flags & RTNH_F_DEAD)
2037 continue;
2038 last_tos = fa->fa_tos;
2039 last_prio = next_fi->fib_priority;
2040
2041 if (next_fi->fib_scope != res->scope ||
2042 fa->fa_type != RTN_UNICAST)
2043 continue;
2044
2045 nhc = fib_info_nhc(next_fi, 0);
2046 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2047 continue;
2048
2049 fib_alias_accessed(fa);
2050
2051 if (!fi) {
2052 if (next_fi != res->fi)
2053 break;
2054 fa1 = fa;
2055 } else if (!fib_detect_death(fi, order, &last_resort,
2056 &last_idx, fa1->fa_default)) {
2057 fib_result_assign(res, fi);
2058 fa1->fa_default = order;
2059 goto out;
2060 }
2061 fi = next_fi;
2062 order++;
2063 }
2064
2065 if (order <= 0 || !fi) {
2066 if (fa1)
2067 fa1->fa_default = -1;
2068 goto out;
2069 }
2070
2071 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2072 fa1->fa_default)) {
2073 fib_result_assign(res, fi);
2074 fa1->fa_default = order;
2075 goto out;
2076 }
2077
2078 if (last_idx >= 0)
2079 fib_result_assign(res, last_resort);
2080 fa1->fa_default = last_idx;
2081 out:
2082 return;
2083 }
2084
2085 /*
2086 * Dead device goes up. We wake up dead nexthops.
2087 * It takes sense only on multipath routes.
2088 *
2089 * only used when fib_nh is built into fib_info
2090 */
fib_sync_up(struct net_device * dev,unsigned char nh_flags)2091 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2092 {
2093 struct fib_info *prev_fi;
2094 unsigned int hash;
2095 struct hlist_head *head;
2096 struct fib_nh *nh;
2097 int ret;
2098
2099 if (!(dev->flags & IFF_UP))
2100 return 0;
2101
2102 if (nh_flags & RTNH_F_DEAD) {
2103 unsigned int flags = dev_get_flags(dev);
2104
2105 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2106 nh_flags |= RTNH_F_LINKDOWN;
2107 }
2108
2109 prev_fi = NULL;
2110 hash = fib_devindex_hashfn(dev->ifindex);
2111 head = &fib_info_devhash[hash];
2112 ret = 0;
2113
2114 hlist_for_each_entry(nh, head, nh_hash) {
2115 struct fib_info *fi = nh->nh_parent;
2116 int alive;
2117
2118 BUG_ON(!fi->fib_nhs);
2119 if (nh->fib_nh_dev != dev || fi == prev_fi)
2120 continue;
2121
2122 prev_fi = fi;
2123 alive = 0;
2124 change_nexthops(fi) {
2125 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2126 alive++;
2127 continue;
2128 }
2129 if (!nexthop_nh->fib_nh_dev ||
2130 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2131 continue;
2132 if (nexthop_nh->fib_nh_dev != dev ||
2133 !__in_dev_get_rtnl(dev))
2134 continue;
2135 alive++;
2136 nexthop_nh->fib_nh_flags &= ~nh_flags;
2137 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2138 } endfor_nexthops(fi)
2139
2140 if (alive > 0) {
2141 fi->fib_flags &= ~nh_flags;
2142 ret++;
2143 }
2144
2145 fib_rebalance(fi);
2146 }
2147
2148 return ret;
2149 }
2150
2151 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_good_nh(const struct fib_nh * nh)2152 static bool fib_good_nh(const struct fib_nh *nh)
2153 {
2154 int state = NUD_REACHABLE;
2155
2156 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2157 struct neighbour *n;
2158
2159 rcu_read_lock_bh();
2160
2161 if (likely(nh->fib_nh_gw_family == AF_INET))
2162 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2163 (__force u32)nh->fib_nh_gw4);
2164 else if (nh->fib_nh_gw_family == AF_INET6)
2165 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2166 &nh->fib_nh_gw6);
2167 else
2168 n = NULL;
2169 if (n)
2170 state = n->nud_state;
2171
2172 rcu_read_unlock_bh();
2173 }
2174
2175 return !!(state & NUD_VALID);
2176 }
2177
fib_select_multipath(struct fib_result * res,int hash)2178 void fib_select_multipath(struct fib_result *res, int hash)
2179 {
2180 struct fib_info *fi = res->fi;
2181 struct net *net = fi->fib_net;
2182 bool first = false;
2183
2184 if (unlikely(res->fi->nh)) {
2185 nexthop_path_fib_result(res, hash);
2186 return;
2187 }
2188
2189 change_nexthops(fi) {
2190 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
2191 if (!fib_good_nh(nexthop_nh))
2192 continue;
2193 if (!first) {
2194 res->nh_sel = nhsel;
2195 res->nhc = &nexthop_nh->nh_common;
2196 first = true;
2197 }
2198 }
2199
2200 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2201 continue;
2202
2203 res->nh_sel = nhsel;
2204 res->nhc = &nexthop_nh->nh_common;
2205 return;
2206 } endfor_nexthops(fi);
2207 }
2208 #endif
2209
fib_select_path(struct net * net,struct fib_result * res,struct flowi4 * fl4,const struct sk_buff * skb)2210 void fib_select_path(struct net *net, struct fib_result *res,
2211 struct flowi4 *fl4, const struct sk_buff *skb)
2212 {
2213 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2214 goto check_saddr;
2215
2216 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2217 if (fib_info_num_path(res->fi) > 1) {
2218 int h = fib_multipath_hash(net, fl4, skb, NULL);
2219
2220 fib_select_multipath(res, h);
2221 }
2222 else
2223 #endif
2224 if (!res->prefixlen &&
2225 res->table->tb_num_default > 1 &&
2226 res->type == RTN_UNICAST)
2227 fib_select_default(fl4, res);
2228
2229 check_saddr:
2230 if (!fl4->saddr)
2231 fl4->saddr = fib_result_prefsrc(net, res);
2232 }
2233