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