1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: semantics.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/uaccess.h>
13 #include <linux/bitops.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/jiffies.h>
17 #include <linux/mm.h>
18 #include <linux/string.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/errno.h>
22 #include <linux/in.h>
23 #include <linux/inet.h>
24 #include <linux/inetdevice.h>
25 #include <linux/netdevice.h>
26 #include <linux/if_arp.h>
27 #include <linux/proc_fs.h>
28 #include <linux/skbuff.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/netlink.h>
32 #include <linux/hash.h>
33
34 #include <net/arp.h>
35 #include <net/inet_dscp.h>
36 #include <net/ip.h>
37 #include <net/protocol.h>
38 #include <net/route.h>
39 #include <net/tcp.h>
40 #include <net/sock.h>
41 #include <net/ip_fib.h>
42 #include <net/ip6_fib.h>
43 #include <net/nexthop.h>
44 #include <net/netlink.h>
45 #include <net/rtnh.h>
46 #include <net/lwtunnel.h>
47 #include <net/fib_notifier.h>
48 #include <net/addrconf.h>
49
50 #include "fib_lookup.h"
51
52 static DEFINE_SPINLOCK(fib_info_lock);
53 static struct hlist_head *fib_info_hash;
54 static struct hlist_head *fib_info_laddrhash;
55 static unsigned int fib_info_hash_size;
56 static unsigned int fib_info_hash_bits;
57 static unsigned int fib_info_cnt;
58
59 #define DEVINDEX_HASHBITS 8
60 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
61 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
62
63 /* for_nexthops and change_nexthops only used when nexthop object
64 * is not set in a fib_info. The logic within can reference fib_nh.
65 */
66 #ifdef CONFIG_IP_ROUTE_MULTIPATH
67
68 #define for_nexthops(fi) { \
69 int nhsel; const struct fib_nh *nh; \
70 for (nhsel = 0, nh = (fi)->fib_nh; \
71 nhsel < fib_info_num_path((fi)); \
72 nh++, nhsel++)
73
74 #define change_nexthops(fi) { \
75 int nhsel; struct fib_nh *nexthop_nh; \
76 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
77 nhsel < fib_info_num_path((fi)); \
78 nexthop_nh++, nhsel++)
79
80 #else /* CONFIG_IP_ROUTE_MULTIPATH */
81
82 /* Hope, that gcc will optimize it to get rid of dummy loop */
83
84 #define for_nexthops(fi) { \
85 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
86 for (nhsel = 0; nhsel < 1; nhsel++)
87
88 #define change_nexthops(fi) { \
89 int nhsel; \
90 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
91 for (nhsel = 0; nhsel < 1; nhsel++)
92
93 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
94
95 #define endfor_nexthops(fi) }
96
97
98 const struct fib_prop fib_props[RTN_MAX + 1] = {
99 [RTN_UNSPEC] = {
100 .error = 0,
101 .scope = RT_SCOPE_NOWHERE,
102 },
103 [RTN_UNICAST] = {
104 .error = 0,
105 .scope = RT_SCOPE_UNIVERSE,
106 },
107 [RTN_LOCAL] = {
108 .error = 0,
109 .scope = RT_SCOPE_HOST,
110 },
111 [RTN_BROADCAST] = {
112 .error = 0,
113 .scope = RT_SCOPE_LINK,
114 },
115 [RTN_ANYCAST] = {
116 .error = 0,
117 .scope = RT_SCOPE_LINK,
118 },
119 [RTN_MULTICAST] = {
120 .error = 0,
121 .scope = RT_SCOPE_UNIVERSE,
122 },
123 [RTN_BLACKHOLE] = {
124 .error = -EINVAL,
125 .scope = RT_SCOPE_UNIVERSE,
126 },
127 [RTN_UNREACHABLE] = {
128 .error = -EHOSTUNREACH,
129 .scope = RT_SCOPE_UNIVERSE,
130 },
131 [RTN_PROHIBIT] = {
132 .error = -EACCES,
133 .scope = RT_SCOPE_UNIVERSE,
134 },
135 [RTN_THROW] = {
136 .error = -EAGAIN,
137 .scope = RT_SCOPE_UNIVERSE,
138 },
139 [RTN_NAT] = {
140 .error = -EINVAL,
141 .scope = RT_SCOPE_NOWHERE,
142 },
143 [RTN_XRESOLVE] = {
144 .error = -EINVAL,
145 .scope = RT_SCOPE_NOWHERE,
146 },
147 };
148
rt_fibinfo_free(struct rtable __rcu ** rtp)149 static void rt_fibinfo_free(struct rtable __rcu **rtp)
150 {
151 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
152
153 if (!rt)
154 return;
155
156 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
157 * because we waited an RCU grace period before calling
158 * free_fib_info_rcu()
159 */
160
161 dst_dev_put(&rt->dst);
162 dst_release_immediate(&rt->dst);
163 }
164
free_nh_exceptions(struct fib_nh_common * nhc)165 static void free_nh_exceptions(struct fib_nh_common *nhc)
166 {
167 struct fnhe_hash_bucket *hash;
168 int i;
169
170 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
171 if (!hash)
172 return;
173 for (i = 0; i < FNHE_HASH_SIZE; i++) {
174 struct fib_nh_exception *fnhe;
175
176 fnhe = rcu_dereference_protected(hash[i].chain, 1);
177 while (fnhe) {
178 struct fib_nh_exception *next;
179
180 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
181
182 rt_fibinfo_free(&fnhe->fnhe_rth_input);
183 rt_fibinfo_free(&fnhe->fnhe_rth_output);
184
185 kfree(fnhe);
186
187 fnhe = next;
188 }
189 }
190 kfree(hash);
191 }
192
rt_fibinfo_free_cpus(struct rtable __rcu * __percpu * rtp)193 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
194 {
195 int cpu;
196
197 if (!rtp)
198 return;
199
200 for_each_possible_cpu(cpu) {
201 struct rtable *rt;
202
203 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
204 if (rt) {
205 dst_dev_put(&rt->dst);
206 dst_release_immediate(&rt->dst);
207 }
208 }
209 free_percpu(rtp);
210 }
211
fib_nh_common_release(struct fib_nh_common * nhc)212 void fib_nh_common_release(struct fib_nh_common *nhc)
213 {
214 dev_put_track(nhc->nhc_dev, &nhc->nhc_dev_tracker);
215 lwtstate_put(nhc->nhc_lwtstate);
216 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
217 rt_fibinfo_free(&nhc->nhc_rth_input);
218 free_nh_exceptions(nhc);
219 }
220 EXPORT_SYMBOL_GPL(fib_nh_common_release);
221
fib_nh_release(struct net * net,struct fib_nh * fib_nh)222 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
223 {
224 #ifdef CONFIG_IP_ROUTE_CLASSID
225 if (fib_nh->nh_tclassid)
226 atomic_dec(&net->ipv4.fib_num_tclassid_users);
227 #endif
228 fib_nh_common_release(&fib_nh->nh_common);
229 }
230
231 /* Release a nexthop info record */
free_fib_info_rcu(struct rcu_head * head)232 static void free_fib_info_rcu(struct rcu_head *head)
233 {
234 struct fib_info *fi = container_of(head, struct fib_info, rcu);
235
236 if (fi->nh) {
237 nexthop_put(fi->nh);
238 } else {
239 change_nexthops(fi) {
240 fib_nh_release(fi->fib_net, nexthop_nh);
241 } endfor_nexthops(fi);
242 }
243
244 ip_fib_metrics_put(fi->fib_metrics);
245
246 kfree(fi);
247 }
248
free_fib_info(struct fib_info * fi)249 void free_fib_info(struct fib_info *fi)
250 {
251 if (fi->fib_dead == 0) {
252 pr_warn("Freeing alive fib_info %p\n", fi);
253 return;
254 }
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 && refcount_dec_and_test(&fi->fib_treeref)) {
264 hlist_del(&fi->fib_hash);
265
266 /* Paired with READ_ONCE() in fib_create_info(). */
267 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
268
269 if (fi->fib_prefsrc)
270 hlist_del(&fi->fib_lhash);
271 if (fi->nh) {
272 list_del(&fi->nh_list);
273 } else {
274 change_nexthops(fi) {
275 if (!nexthop_nh->fib_nh_dev)
276 continue;
277 hlist_del(&nexthop_nh->nh_hash);
278 } endfor_nexthops(fi)
279 }
280 fi->fib_dead = 1;
281 fib_info_put(fi);
282 }
283 spin_unlock_bh(&fib_info_lock);
284 }
285
nh_comp(struct fib_info * fi,struct fib_info * ofi)286 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
287 {
288 const struct fib_nh *onh;
289
290 if (fi->nh || ofi->nh)
291 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
292
293 if (ofi->fib_nhs == 0)
294 return 0;
295
296 for_nexthops(fi) {
297 onh = fib_info_nh(ofi, nhsel);
298
299 if (nh->fib_nh_oif != onh->fib_nh_oif ||
300 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
301 nh->fib_nh_scope != onh->fib_nh_scope ||
302 #ifdef CONFIG_IP_ROUTE_MULTIPATH
303 nh->fib_nh_weight != onh->fib_nh_weight ||
304 #endif
305 #ifdef CONFIG_IP_ROUTE_CLASSID
306 nh->nh_tclassid != onh->nh_tclassid ||
307 #endif
308 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
309 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
310 return -1;
311
312 if (nh->fib_nh_gw_family == AF_INET &&
313 nh->fib_nh_gw4 != onh->fib_nh_gw4)
314 return -1;
315
316 if (nh->fib_nh_gw_family == AF_INET6 &&
317 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
318 return -1;
319 } endfor_nexthops(fi);
320 return 0;
321 }
322
fib_devindex_hashfn(unsigned int val)323 static inline unsigned int fib_devindex_hashfn(unsigned int val)
324 {
325 return hash_32(val, DEVINDEX_HASHBITS);
326 }
327
328 static struct hlist_head *
fib_info_devhash_bucket(const struct net_device * dev)329 fib_info_devhash_bucket(const struct net_device *dev)
330 {
331 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
332
333 return &fib_info_devhash[fib_devindex_hashfn(val)];
334 }
335
fib_info_hashfn_1(int init_val,u8 protocol,u8 scope,u32 prefsrc,u32 priority)336 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
337 u32 prefsrc, u32 priority)
338 {
339 unsigned int val = init_val;
340
341 val ^= (protocol << 8) | scope;
342 val ^= prefsrc;
343 val ^= priority;
344
345 return val;
346 }
347
fib_info_hashfn_result(unsigned int val)348 static unsigned int fib_info_hashfn_result(unsigned int val)
349 {
350 unsigned int mask = (fib_info_hash_size - 1);
351
352 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
353 }
354
fib_info_hashfn(struct fib_info * fi)355 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
356 {
357 unsigned int val;
358
359 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
360 fi->fib_scope, (__force u32)fi->fib_prefsrc,
361 fi->fib_priority);
362
363 if (fi->nh) {
364 val ^= fib_devindex_hashfn(fi->nh->id);
365 } else {
366 for_nexthops(fi) {
367 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
368 } endfor_nexthops(fi)
369 }
370
371 return fib_info_hashfn_result(val);
372 }
373
374 /* no metrics, only nexthop id */
fib_find_info_nh(struct net * net,const struct fib_config * cfg)375 static struct fib_info *fib_find_info_nh(struct net *net,
376 const struct fib_config *cfg)
377 {
378 struct hlist_head *head;
379 struct fib_info *fi;
380 unsigned int hash;
381
382 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
383 cfg->fc_protocol, cfg->fc_scope,
384 (__force u32)cfg->fc_prefsrc,
385 cfg->fc_priority);
386 hash = fib_info_hashfn_result(hash);
387 head = &fib_info_hash[hash];
388
389 hlist_for_each_entry(fi, head, fib_hash) {
390 if (!net_eq(fi->fib_net, net))
391 continue;
392 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
393 continue;
394 if (cfg->fc_protocol == fi->fib_protocol &&
395 cfg->fc_scope == fi->fib_scope &&
396 cfg->fc_prefsrc == fi->fib_prefsrc &&
397 cfg->fc_priority == fi->fib_priority &&
398 cfg->fc_type == fi->fib_type &&
399 cfg->fc_table == fi->fib_tb_id &&
400 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
401 return fi;
402 }
403
404 return NULL;
405 }
406
fib_find_info(struct fib_info * nfi)407 static struct fib_info *fib_find_info(struct fib_info *nfi)
408 {
409 struct hlist_head *head;
410 struct fib_info *fi;
411 unsigned int hash;
412
413 hash = fib_info_hashfn(nfi);
414 head = &fib_info_hash[hash];
415
416 hlist_for_each_entry(fi, head, fib_hash) {
417 if (!net_eq(fi->fib_net, nfi->fib_net))
418 continue;
419 if (fi->fib_nhs != nfi->fib_nhs)
420 continue;
421 if (nfi->fib_protocol == fi->fib_protocol &&
422 nfi->fib_scope == fi->fib_scope &&
423 nfi->fib_prefsrc == fi->fib_prefsrc &&
424 nfi->fib_priority == fi->fib_priority &&
425 nfi->fib_type == fi->fib_type &&
426 memcmp(nfi->fib_metrics, fi->fib_metrics,
427 sizeof(u32) * RTAX_MAX) == 0 &&
428 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
429 nh_comp(fi, nfi) == 0)
430 return fi;
431 }
432
433 return NULL;
434 }
435
436 /* Check, that the gateway is already configured.
437 * Used only by redirect accept routine.
438 */
ip_fib_check_default(__be32 gw,struct net_device * dev)439 int ip_fib_check_default(__be32 gw, struct net_device *dev)
440 {
441 struct hlist_head *head;
442 struct fib_nh *nh;
443
444 spin_lock(&fib_info_lock);
445
446 head = fib_info_devhash_bucket(dev);
447
448 hlist_for_each_entry(nh, head, nh_hash) {
449 if (nh->fib_nh_dev == dev &&
450 nh->fib_nh_gw4 == gw &&
451 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
452 spin_unlock(&fib_info_lock);
453 return 0;
454 }
455 }
456
457 spin_unlock(&fib_info_lock);
458
459 return -1;
460 }
461
fib_nlmsg_size(struct fib_info * fi)462 size_t fib_nlmsg_size(struct fib_info *fi)
463 {
464 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
465 + nla_total_size(4) /* RTA_TABLE */
466 + nla_total_size(4) /* RTA_DST */
467 + nla_total_size(4) /* RTA_PRIORITY */
468 + nla_total_size(4) /* RTA_PREFSRC */
469 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
470 unsigned int nhs = fib_info_num_path(fi);
471
472 /* space for nested metrics */
473 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
474
475 if (fi->nh)
476 payload += nla_total_size(4); /* RTA_NH_ID */
477
478 if (nhs) {
479 size_t nh_encapsize = 0;
480 /* Also handles the special case nhs == 1 */
481
482 /* each nexthop is packed in an attribute */
483 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
484 unsigned int i;
485
486 /* may contain flow and gateway attribute */
487 nhsize += 2 * nla_total_size(4);
488
489 /* grab encap info */
490 for (i = 0; i < fib_info_num_path(fi); i++) {
491 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
492
493 if (nhc->nhc_lwtstate) {
494 /* RTA_ENCAP_TYPE */
495 nh_encapsize += lwtunnel_get_encap_size(
496 nhc->nhc_lwtstate);
497 /* RTA_ENCAP */
498 nh_encapsize += nla_total_size(2);
499 }
500 }
501
502 /* all nexthops are packed in a nested attribute */
503 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
504
505 }
506
507 return payload;
508 }
509
rtmsg_fib(int event,__be32 key,struct fib_alias * fa,int dst_len,u32 tb_id,const struct nl_info * info,unsigned int nlm_flags)510 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
511 int dst_len, u32 tb_id, const struct nl_info *info,
512 unsigned int nlm_flags)
513 {
514 struct fib_rt_info fri;
515 struct sk_buff *skb;
516 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
517 int err = -ENOBUFS;
518
519 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
520 if (!skb)
521 goto errout;
522
523 fri.fi = fa->fa_info;
524 fri.tb_id = tb_id;
525 fri.dst = key;
526 fri.dst_len = dst_len;
527 fri.dscp = fa->fa_dscp;
528 fri.type = fa->fa_type;
529 fri.offload = READ_ONCE(fa->offload);
530 fri.trap = READ_ONCE(fa->trap);
531 fri.offload_failed = READ_ONCE(fa->offload_failed);
532 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
533 if (err < 0) {
534 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
535 WARN_ON(err == -EMSGSIZE);
536 kfree_skb(skb);
537 goto errout;
538 }
539 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
540 info->nlh, GFP_KERNEL);
541 return;
542 errout:
543 if (err < 0)
544 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
545 }
546
fib_detect_death(struct fib_info * fi,int order,struct fib_info ** last_resort,int * last_idx,int dflt)547 static int fib_detect_death(struct fib_info *fi, int order,
548 struct fib_info **last_resort, int *last_idx,
549 int dflt)
550 {
551 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
552 struct neighbour *n;
553 int state = NUD_NONE;
554
555 if (likely(nhc->nhc_gw_family == AF_INET))
556 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
557 else if (nhc->nhc_gw_family == AF_INET6)
558 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
559 nhc->nhc_dev);
560 else
561 n = NULL;
562
563 if (n) {
564 state = n->nud_state;
565 neigh_release(n);
566 } else {
567 return 0;
568 }
569 if (state == NUD_REACHABLE)
570 return 0;
571 if ((state & NUD_VALID) && order != dflt)
572 return 0;
573 if ((state & NUD_VALID) ||
574 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
575 *last_resort = fi;
576 *last_idx = order;
577 }
578 return 1;
579 }
580
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)581 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
582 struct nlattr *encap, u16 encap_type,
583 void *cfg, gfp_t gfp_flags,
584 struct netlink_ext_ack *extack)
585 {
586 int err;
587
588 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
589 gfp_flags);
590 if (!nhc->nhc_pcpu_rth_output)
591 return -ENOMEM;
592
593 if (encap) {
594 struct lwtunnel_state *lwtstate;
595
596 if (encap_type == LWTUNNEL_ENCAP_NONE) {
597 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
598 err = -EINVAL;
599 goto lwt_failure;
600 }
601 err = lwtunnel_build_state(net, encap_type, encap,
602 nhc->nhc_family, cfg, &lwtstate,
603 extack);
604 if (err)
605 goto lwt_failure;
606
607 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
608 }
609
610 return 0;
611
612 lwt_failure:
613 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
614 nhc->nhc_pcpu_rth_output = NULL;
615 return err;
616 }
617 EXPORT_SYMBOL_GPL(fib_nh_common_init);
618
fib_nh_init(struct net * net,struct fib_nh * nh,struct fib_config * cfg,int nh_weight,struct netlink_ext_ack * extack)619 int fib_nh_init(struct net *net, struct fib_nh *nh,
620 struct fib_config *cfg, int nh_weight,
621 struct netlink_ext_ack *extack)
622 {
623 int err;
624
625 nh->fib_nh_family = AF_INET;
626
627 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
628 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
629 if (err)
630 return err;
631
632 nh->fib_nh_oif = cfg->fc_oif;
633 nh->fib_nh_gw_family = cfg->fc_gw_family;
634 if (cfg->fc_gw_family == AF_INET)
635 nh->fib_nh_gw4 = cfg->fc_gw4;
636 else if (cfg->fc_gw_family == AF_INET6)
637 nh->fib_nh_gw6 = cfg->fc_gw6;
638
639 nh->fib_nh_flags = cfg->fc_flags;
640
641 #ifdef CONFIG_IP_ROUTE_CLASSID
642 nh->nh_tclassid = cfg->fc_flow;
643 if (nh->nh_tclassid)
644 atomic_inc(&net->ipv4.fib_num_tclassid_users);
645 #endif
646 #ifdef CONFIG_IP_ROUTE_MULTIPATH
647 nh->fib_nh_weight = nh_weight;
648 #endif
649 return 0;
650 }
651
652 #ifdef CONFIG_IP_ROUTE_MULTIPATH
653
fib_count_nexthops(struct rtnexthop * rtnh,int remaining,struct netlink_ext_ack * extack)654 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
655 struct netlink_ext_ack *extack)
656 {
657 int nhs = 0;
658
659 while (rtnh_ok(rtnh, remaining)) {
660 nhs++;
661 rtnh = rtnh_next(rtnh, &remaining);
662 }
663
664 /* leftover implies invalid nexthop configuration, discard it */
665 if (remaining > 0) {
666 NL_SET_ERR_MSG(extack,
667 "Invalid nexthop configuration - extra data after nexthops");
668 nhs = 0;
669 }
670
671 return nhs;
672 }
673
fib_gw_from_attr(__be32 * gw,struct nlattr * nla,struct netlink_ext_ack * extack)674 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
675 struct netlink_ext_ack *extack)
676 {
677 if (nla_len(nla) < sizeof(*gw)) {
678 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
679 return -EINVAL;
680 }
681
682 *gw = nla_get_in_addr(nla);
683
684 return 0;
685 }
686
687 /* 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)688 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
689 int remaining, struct fib_config *cfg,
690 struct netlink_ext_ack *extack)
691 {
692 struct net *net = fi->fib_net;
693 struct fib_config fib_cfg;
694 struct fib_nh *nh;
695 int ret;
696
697 change_nexthops(fi) {
698 int attrlen;
699
700 memset(&fib_cfg, 0, sizeof(fib_cfg));
701
702 if (!rtnh_ok(rtnh, remaining)) {
703 NL_SET_ERR_MSG(extack,
704 "Invalid nexthop configuration - extra data after nexthop");
705 return -EINVAL;
706 }
707
708 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
709 NL_SET_ERR_MSG(extack,
710 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
711 return -EINVAL;
712 }
713
714 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
715 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
716
717 attrlen = rtnh_attrlen(rtnh);
718 if (attrlen > 0) {
719 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
720
721 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
722 nlav = nla_find(attrs, attrlen, RTA_VIA);
723 if (nla && nlav) {
724 NL_SET_ERR_MSG(extack,
725 "Nexthop configuration can not contain both GATEWAY and VIA");
726 return -EINVAL;
727 }
728 if (nla) {
729 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
730 extack);
731 if (ret)
732 goto errout;
733
734 if (fib_cfg.fc_gw4)
735 fib_cfg.fc_gw_family = AF_INET;
736 } else if (nlav) {
737 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
738 if (ret)
739 goto errout;
740 }
741
742 nla = nla_find(attrs, attrlen, RTA_FLOW);
743 if (nla) {
744 if (nla_len(nla) < sizeof(u32)) {
745 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
746 return -EINVAL;
747 }
748 fib_cfg.fc_flow = nla_get_u32(nla);
749 }
750
751 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
752 /* RTA_ENCAP_TYPE length checked in
753 * lwtunnel_valid_encap_type_attr
754 */
755 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
756 if (nla)
757 fib_cfg.fc_encap_type = nla_get_u16(nla);
758 }
759
760 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
761 rtnh->rtnh_hops + 1, extack);
762 if (ret)
763 goto errout;
764
765 rtnh = rtnh_next(rtnh, &remaining);
766 } endfor_nexthops(fi);
767
768 ret = -EINVAL;
769 nh = fib_info_nh(fi, 0);
770 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
771 NL_SET_ERR_MSG(extack,
772 "Nexthop device index does not match RTA_OIF");
773 goto errout;
774 }
775 if (cfg->fc_gw_family) {
776 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
777 (cfg->fc_gw_family == AF_INET &&
778 nh->fib_nh_gw4 != cfg->fc_gw4) ||
779 (cfg->fc_gw_family == AF_INET6 &&
780 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
781 NL_SET_ERR_MSG(extack,
782 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
783 goto errout;
784 }
785 }
786 #ifdef CONFIG_IP_ROUTE_CLASSID
787 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
788 NL_SET_ERR_MSG(extack,
789 "Nexthop class id does not match RTA_FLOW");
790 goto errout;
791 }
792 #endif
793 ret = 0;
794 errout:
795 return ret;
796 }
797
798 /* only called when fib_nh is integrated into fib_info */
fib_rebalance(struct fib_info * fi)799 static void fib_rebalance(struct fib_info *fi)
800 {
801 int total;
802 int w;
803
804 if (fib_info_num_path(fi) < 2)
805 return;
806
807 total = 0;
808 for_nexthops(fi) {
809 if (nh->fib_nh_flags & RTNH_F_DEAD)
810 continue;
811
812 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
813 nh->fib_nh_flags & RTNH_F_LINKDOWN)
814 continue;
815
816 total += nh->fib_nh_weight;
817 } endfor_nexthops(fi);
818
819 w = 0;
820 change_nexthops(fi) {
821 int upper_bound;
822
823 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
824 upper_bound = -1;
825 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
826 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
827 upper_bound = -1;
828 } else {
829 w += nexthop_nh->fib_nh_weight;
830 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
831 total) - 1;
832 }
833
834 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
835 } endfor_nexthops(fi);
836 }
837 #else /* CONFIG_IP_ROUTE_MULTIPATH */
838
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)839 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
840 int remaining, struct fib_config *cfg,
841 struct netlink_ext_ack *extack)
842 {
843 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
844
845 return -EINVAL;
846 }
847
848 #define fib_rebalance(fi) do { } while (0)
849
850 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
851
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)852 static int fib_encap_match(struct net *net, u16 encap_type,
853 struct nlattr *encap,
854 const struct fib_nh *nh,
855 const struct fib_config *cfg,
856 struct netlink_ext_ack *extack)
857 {
858 struct lwtunnel_state *lwtstate;
859 int ret, result = 0;
860
861 if (encap_type == LWTUNNEL_ENCAP_NONE)
862 return 0;
863
864 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
865 cfg, &lwtstate, extack);
866 if (!ret) {
867 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
868 lwtstate_free(lwtstate);
869 }
870
871 return result;
872 }
873
fib_nh_match(struct net * net,struct fib_config * cfg,struct fib_info * fi,struct netlink_ext_ack * extack)874 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
875 struct netlink_ext_ack *extack)
876 {
877 #ifdef CONFIG_IP_ROUTE_MULTIPATH
878 struct rtnexthop *rtnh;
879 int remaining;
880 #endif
881
882 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
883 return 1;
884
885 if (cfg->fc_nh_id) {
886 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
887 return 0;
888 return 1;
889 }
890
891 if (cfg->fc_oif || cfg->fc_gw_family) {
892 struct fib_nh *nh;
893
894 /* cannot match on nexthop object attributes */
895 if (fi->nh)
896 return 1;
897
898 nh = fib_info_nh(fi, 0);
899 if (cfg->fc_encap) {
900 if (fib_encap_match(net, cfg->fc_encap_type,
901 cfg->fc_encap, nh, cfg, extack))
902 return 1;
903 }
904 #ifdef CONFIG_IP_ROUTE_CLASSID
905 if (cfg->fc_flow &&
906 cfg->fc_flow != nh->nh_tclassid)
907 return 1;
908 #endif
909 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
910 (cfg->fc_gw_family &&
911 cfg->fc_gw_family != nh->fib_nh_gw_family))
912 return 1;
913
914 if (cfg->fc_gw_family == AF_INET &&
915 cfg->fc_gw4 != nh->fib_nh_gw4)
916 return 1;
917
918 if (cfg->fc_gw_family == AF_INET6 &&
919 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
920 return 1;
921
922 return 0;
923 }
924
925 #ifdef CONFIG_IP_ROUTE_MULTIPATH
926 if (!cfg->fc_mp)
927 return 0;
928
929 rtnh = cfg->fc_mp;
930 remaining = cfg->fc_mp_len;
931
932 for_nexthops(fi) {
933 int attrlen;
934
935 if (!rtnh_ok(rtnh, remaining))
936 return -EINVAL;
937
938 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
939 return 1;
940
941 attrlen = rtnh_attrlen(rtnh);
942 if (attrlen > 0) {
943 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
944 int err;
945
946 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
947 nlav = nla_find(attrs, attrlen, RTA_VIA);
948 if (nla && nlav) {
949 NL_SET_ERR_MSG(extack,
950 "Nexthop configuration can not contain both GATEWAY and VIA");
951 return -EINVAL;
952 }
953
954 if (nla) {
955 __be32 gw;
956
957 err = fib_gw_from_attr(&gw, nla, extack);
958 if (err)
959 return err;
960
961 if (nh->fib_nh_gw_family != AF_INET ||
962 gw != nh->fib_nh_gw4)
963 return 1;
964 } else if (nlav) {
965 struct fib_config cfg2;
966
967 err = fib_gw_from_via(&cfg2, nlav, extack);
968 if (err)
969 return err;
970
971 switch (nh->fib_nh_gw_family) {
972 case AF_INET:
973 if (cfg2.fc_gw_family != AF_INET ||
974 cfg2.fc_gw4 != nh->fib_nh_gw4)
975 return 1;
976 break;
977 case AF_INET6:
978 if (cfg2.fc_gw_family != AF_INET6 ||
979 ipv6_addr_cmp(&cfg2.fc_gw6,
980 &nh->fib_nh_gw6))
981 return 1;
982 break;
983 }
984 }
985
986 #ifdef CONFIG_IP_ROUTE_CLASSID
987 nla = nla_find(attrs, attrlen, RTA_FLOW);
988 if (nla) {
989 if (nla_len(nla) < sizeof(u32)) {
990 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
991 return -EINVAL;
992 }
993 if (nla_get_u32(nla) != nh->nh_tclassid)
994 return 1;
995 }
996 #endif
997 }
998
999 rtnh = rtnh_next(rtnh, &remaining);
1000 } endfor_nexthops(fi);
1001 #endif
1002 return 0;
1003 }
1004
fib_metrics_match(struct fib_config * cfg,struct fib_info * fi)1005 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1006 {
1007 struct nlattr *nla;
1008 int remaining;
1009
1010 if (!cfg->fc_mx)
1011 return true;
1012
1013 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1014 int type = nla_type(nla);
1015 u32 fi_val, val;
1016
1017 if (!type)
1018 continue;
1019 if (type > RTAX_MAX)
1020 return false;
1021
1022 if (type == RTAX_CC_ALGO) {
1023 char tmp[TCP_CA_NAME_MAX];
1024 bool ecn_ca = false;
1025
1026 nla_strscpy(tmp, nla, sizeof(tmp));
1027 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1028 } else {
1029 if (nla_len(nla) != sizeof(u32))
1030 return false;
1031 val = nla_get_u32(nla);
1032 }
1033
1034 fi_val = fi->fib_metrics->metrics[type - 1];
1035 if (type == RTAX_FEATURES)
1036 fi_val &= ~DST_FEATURE_ECN_CA;
1037
1038 if (fi_val != val)
1039 return false;
1040 }
1041
1042 return true;
1043 }
1044
fib_check_nh_v6_gw(struct net * net,struct fib_nh * nh,u32 table,struct netlink_ext_ack * extack)1045 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1046 u32 table, struct netlink_ext_ack *extack)
1047 {
1048 struct fib6_config cfg = {
1049 .fc_table = table,
1050 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1051 .fc_ifindex = nh->fib_nh_oif,
1052 .fc_gateway = nh->fib_nh_gw6,
1053 };
1054 struct fib6_nh fib6_nh = {};
1055 int err;
1056
1057 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1058 if (!err) {
1059 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1060 dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_KERNEL);
1061 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1062 nh->fib_nh_scope = RT_SCOPE_LINK;
1063
1064 ipv6_stub->fib6_nh_release(&fib6_nh);
1065 }
1066
1067 return err;
1068 }
1069
1070 /*
1071 * Picture
1072 * -------
1073 *
1074 * Semantics of nexthop is very messy by historical reasons.
1075 * We have to take into account, that:
1076 * a) gateway can be actually local interface address,
1077 * so that gatewayed route is direct.
1078 * b) gateway must be on-link address, possibly
1079 * described not by an ifaddr, but also by a direct route.
1080 * c) If both gateway and interface are specified, they should not
1081 * contradict.
1082 * d) If we use tunnel routes, gateway could be not on-link.
1083 *
1084 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1085 * results in pretty ugly and hairy code with obscure logic.
1086 *
1087 * I chose to generalized it instead, so that the size
1088 * of code does not increase practically, but it becomes
1089 * much more general.
1090 * Every prefix is assigned a "scope" value: "host" is local address,
1091 * "link" is direct route,
1092 * [ ... "site" ... "interior" ... ]
1093 * and "universe" is true gateway route with global meaning.
1094 *
1095 * Every prefix refers to a set of "nexthop"s (gw, oif),
1096 * where gw must have narrower scope. This recursion stops
1097 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1098 * which means that gw is forced to be on link.
1099 *
1100 * Code is still hairy, but now it is apparently logically
1101 * consistent and very flexible. F.e. as by-product it allows
1102 * to co-exists in peace independent exterior and interior
1103 * routing processes.
1104 *
1105 * Normally it looks as following.
1106 *
1107 * {universe prefix} -> (gw, oif) [scope link]
1108 * |
1109 * |-> {link prefix} -> (gw, oif) [scope local]
1110 * |
1111 * |-> {local prefix} (terminal node)
1112 */
fib_check_nh_v4_gw(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1113 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1114 u8 scope, struct netlink_ext_ack *extack)
1115 {
1116 struct net_device *dev;
1117 struct fib_result res;
1118 int err = 0;
1119
1120 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1121 unsigned int addr_type;
1122
1123 if (scope >= RT_SCOPE_LINK) {
1124 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1125 return -EINVAL;
1126 }
1127 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1128 if (!dev) {
1129 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1130 return -ENODEV;
1131 }
1132 if (!(dev->flags & IFF_UP)) {
1133 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1134 return -ENETDOWN;
1135 }
1136 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1137 if (addr_type != RTN_UNICAST) {
1138 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1139 return -EINVAL;
1140 }
1141 if (!netif_carrier_ok(dev))
1142 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1143 nh->fib_nh_dev = dev;
1144 dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1145 nh->fib_nh_scope = RT_SCOPE_LINK;
1146 return 0;
1147 }
1148 rcu_read_lock();
1149 {
1150 struct fib_table *tbl = NULL;
1151 struct flowi4 fl4 = {
1152 .daddr = nh->fib_nh_gw4,
1153 .flowi4_scope = scope + 1,
1154 .flowi4_oif = nh->fib_nh_oif,
1155 .flowi4_iif = LOOPBACK_IFINDEX,
1156 };
1157
1158 /* It is not necessary, but requires a bit of thinking */
1159 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1160 fl4.flowi4_scope = RT_SCOPE_LINK;
1161
1162 if (table && table != RT_TABLE_MAIN)
1163 tbl = fib_get_table(net, table);
1164
1165 if (tbl)
1166 err = fib_table_lookup(tbl, &fl4, &res,
1167 FIB_LOOKUP_IGNORE_LINKSTATE |
1168 FIB_LOOKUP_NOREF);
1169
1170 /* on error or if no table given do full lookup. This
1171 * is needed for example when nexthops are in the local
1172 * table rather than the given table
1173 */
1174 if (!tbl || err) {
1175 err = fib_lookup(net, &fl4, &res,
1176 FIB_LOOKUP_IGNORE_LINKSTATE);
1177 }
1178
1179 if (err) {
1180 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1181 goto out;
1182 }
1183 }
1184
1185 err = -EINVAL;
1186 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1187 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1188 goto out;
1189 }
1190 nh->fib_nh_scope = res.scope;
1191 nh->fib_nh_oif = FIB_RES_OIF(res);
1192 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1193 if (!dev) {
1194 NL_SET_ERR_MSG(extack,
1195 "No egress device for nexthop gateway");
1196 goto out;
1197 }
1198 dev_hold_track(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1199 if (!netif_carrier_ok(dev))
1200 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1201 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1202 out:
1203 rcu_read_unlock();
1204 return err;
1205 }
1206
fib_check_nh_nongw(struct net * net,struct fib_nh * nh,struct netlink_ext_ack * extack)1207 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1208 struct netlink_ext_ack *extack)
1209 {
1210 struct in_device *in_dev;
1211 int err;
1212
1213 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1214 NL_SET_ERR_MSG(extack,
1215 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1216 return -EINVAL;
1217 }
1218
1219 rcu_read_lock();
1220
1221 err = -ENODEV;
1222 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1223 if (!in_dev)
1224 goto out;
1225 err = -ENETDOWN;
1226 if (!(in_dev->dev->flags & IFF_UP)) {
1227 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1228 goto out;
1229 }
1230
1231 nh->fib_nh_dev = in_dev->dev;
1232 dev_hold_track(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1233 nh->fib_nh_scope = RT_SCOPE_LINK;
1234 if (!netif_carrier_ok(nh->fib_nh_dev))
1235 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1236 err = 0;
1237 out:
1238 rcu_read_unlock();
1239 return err;
1240 }
1241
fib_check_nh(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1242 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1243 struct netlink_ext_ack *extack)
1244 {
1245 int err;
1246
1247 if (nh->fib_nh_gw_family == AF_INET)
1248 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1249 else if (nh->fib_nh_gw_family == AF_INET6)
1250 err = fib_check_nh_v6_gw(net, nh, table, extack);
1251 else
1252 err = fib_check_nh_nongw(net, nh, extack);
1253
1254 return err;
1255 }
1256
1257 static struct hlist_head *
fib_info_laddrhash_bucket(const struct net * net,__be32 val)1258 fib_info_laddrhash_bucket(const struct net *net, __be32 val)
1259 {
1260 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val,
1261 fib_info_hash_bits);
1262
1263 return &fib_info_laddrhash[slot];
1264 }
1265
fib_info_hash_move(struct hlist_head * new_info_hash,struct hlist_head * new_laddrhash,unsigned int new_size)1266 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1267 struct hlist_head *new_laddrhash,
1268 unsigned int new_size)
1269 {
1270 struct hlist_head *old_info_hash, *old_laddrhash;
1271 unsigned int old_size = fib_info_hash_size;
1272 unsigned int i;
1273
1274 spin_lock_bh(&fib_info_lock);
1275 old_info_hash = fib_info_hash;
1276 old_laddrhash = fib_info_laddrhash;
1277 fib_info_hash_size = new_size;
1278 fib_info_hash_bits = ilog2(new_size);
1279
1280 for (i = 0; i < old_size; i++) {
1281 struct hlist_head *head = &fib_info_hash[i];
1282 struct hlist_node *n;
1283 struct fib_info *fi;
1284
1285 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1286 struct hlist_head *dest;
1287 unsigned int new_hash;
1288
1289 new_hash = fib_info_hashfn(fi);
1290 dest = &new_info_hash[new_hash];
1291 hlist_add_head(&fi->fib_hash, dest);
1292 }
1293 }
1294 fib_info_hash = new_info_hash;
1295
1296 fib_info_laddrhash = new_laddrhash;
1297 for (i = 0; i < old_size; i++) {
1298 struct hlist_head *lhead = &old_laddrhash[i];
1299 struct hlist_node *n;
1300 struct fib_info *fi;
1301
1302 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1303 struct hlist_head *ldest;
1304
1305 ldest = fib_info_laddrhash_bucket(fi->fib_net,
1306 fi->fib_prefsrc);
1307 hlist_add_head(&fi->fib_lhash, ldest);
1308 }
1309 }
1310
1311 spin_unlock_bh(&fib_info_lock);
1312
1313 kvfree(old_info_hash);
1314 kvfree(old_laddrhash);
1315 }
1316
fib_info_update_nhc_saddr(struct net * net,struct fib_nh_common * nhc,unsigned char scope)1317 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1318 unsigned char scope)
1319 {
1320 struct fib_nh *nh;
1321
1322 if (nhc->nhc_family != AF_INET)
1323 return inet_select_addr(nhc->nhc_dev, 0, scope);
1324
1325 nh = container_of(nhc, struct fib_nh, nh_common);
1326 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1327 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1328
1329 return nh->nh_saddr;
1330 }
1331
fib_result_prefsrc(struct net * net,struct fib_result * res)1332 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1333 {
1334 struct fib_nh_common *nhc = res->nhc;
1335
1336 if (res->fi->fib_prefsrc)
1337 return res->fi->fib_prefsrc;
1338
1339 if (nhc->nhc_family == AF_INET) {
1340 struct fib_nh *nh;
1341
1342 nh = container_of(nhc, struct fib_nh, nh_common);
1343 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1344 return nh->nh_saddr;
1345 }
1346
1347 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1348 }
1349
fib_valid_prefsrc(struct fib_config * cfg,__be32 fib_prefsrc)1350 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1351 {
1352 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1353 fib_prefsrc != cfg->fc_dst) {
1354 u32 tb_id = cfg->fc_table;
1355 int rc;
1356
1357 if (tb_id == RT_TABLE_MAIN)
1358 tb_id = RT_TABLE_LOCAL;
1359
1360 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1361 fib_prefsrc, tb_id);
1362
1363 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1364 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1365 fib_prefsrc, RT_TABLE_LOCAL);
1366 }
1367
1368 if (rc != RTN_LOCAL)
1369 return false;
1370 }
1371 return true;
1372 }
1373
fib_create_info(struct fib_config * cfg,struct netlink_ext_ack * extack)1374 struct fib_info *fib_create_info(struct fib_config *cfg,
1375 struct netlink_ext_ack *extack)
1376 {
1377 int err;
1378 struct fib_info *fi = NULL;
1379 struct nexthop *nh = NULL;
1380 struct fib_info *ofi;
1381 int nhs = 1;
1382 struct net *net = cfg->fc_nlinfo.nl_net;
1383
1384 if (cfg->fc_type > RTN_MAX)
1385 goto err_inval;
1386
1387 /* Fast check to catch the most weird cases */
1388 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1389 NL_SET_ERR_MSG(extack, "Invalid scope");
1390 goto err_inval;
1391 }
1392
1393 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1394 NL_SET_ERR_MSG(extack,
1395 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1396 goto err_inval;
1397 }
1398
1399 if (cfg->fc_nh_id) {
1400 if (!cfg->fc_mx) {
1401 fi = fib_find_info_nh(net, cfg);
1402 if (fi) {
1403 refcount_inc(&fi->fib_treeref);
1404 return fi;
1405 }
1406 }
1407
1408 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1409 if (!nh) {
1410 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1411 goto err_inval;
1412 }
1413 nhs = 0;
1414 }
1415
1416 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1417 if (cfg->fc_mp) {
1418 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1419 if (nhs == 0)
1420 goto err_inval;
1421 }
1422 #endif
1423
1424 err = -ENOBUFS;
1425
1426 /* Paired with WRITE_ONCE() in fib_release_info() */
1427 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) {
1428 unsigned int new_size = fib_info_hash_size << 1;
1429 struct hlist_head *new_info_hash;
1430 struct hlist_head *new_laddrhash;
1431 size_t bytes;
1432
1433 if (!new_size)
1434 new_size = 16;
1435 bytes = (size_t)new_size * sizeof(struct hlist_head *);
1436 new_info_hash = kvzalloc(bytes, GFP_KERNEL);
1437 new_laddrhash = kvzalloc(bytes, GFP_KERNEL);
1438 if (!new_info_hash || !new_laddrhash) {
1439 kvfree(new_info_hash);
1440 kvfree(new_laddrhash);
1441 } else {
1442 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1443 }
1444 if (!fib_info_hash_size)
1445 goto failure;
1446 }
1447
1448 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1449 if (!fi)
1450 goto failure;
1451 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1452 cfg->fc_mx_len, extack);
1453 if (IS_ERR(fi->fib_metrics)) {
1454 err = PTR_ERR(fi->fib_metrics);
1455 kfree(fi);
1456 return ERR_PTR(err);
1457 }
1458
1459 fi->fib_net = net;
1460 fi->fib_protocol = cfg->fc_protocol;
1461 fi->fib_scope = cfg->fc_scope;
1462 fi->fib_flags = cfg->fc_flags;
1463 fi->fib_priority = cfg->fc_priority;
1464 fi->fib_prefsrc = cfg->fc_prefsrc;
1465 fi->fib_type = cfg->fc_type;
1466 fi->fib_tb_id = cfg->fc_table;
1467
1468 fi->fib_nhs = nhs;
1469 if (nh) {
1470 if (!nexthop_get(nh)) {
1471 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1472 err = -EINVAL;
1473 } else {
1474 err = 0;
1475 fi->nh = nh;
1476 }
1477 } else {
1478 change_nexthops(fi) {
1479 nexthop_nh->nh_parent = fi;
1480 } endfor_nexthops(fi)
1481
1482 if (cfg->fc_mp)
1483 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1484 extack);
1485 else
1486 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1487 }
1488
1489 if (err != 0)
1490 goto failure;
1491
1492 if (fib_props[cfg->fc_type].error) {
1493 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1494 NL_SET_ERR_MSG(extack,
1495 "Gateway, device and multipath can not be specified for this route type");
1496 goto err_inval;
1497 }
1498 goto link_it;
1499 } else {
1500 switch (cfg->fc_type) {
1501 case RTN_UNICAST:
1502 case RTN_LOCAL:
1503 case RTN_BROADCAST:
1504 case RTN_ANYCAST:
1505 case RTN_MULTICAST:
1506 break;
1507 default:
1508 NL_SET_ERR_MSG(extack, "Invalid route type");
1509 goto err_inval;
1510 }
1511 }
1512
1513 if (cfg->fc_scope > RT_SCOPE_HOST) {
1514 NL_SET_ERR_MSG(extack, "Invalid scope");
1515 goto err_inval;
1516 }
1517
1518 if (fi->nh) {
1519 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1520 if (err)
1521 goto failure;
1522 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1523 struct fib_nh *nh = fi->fib_nh;
1524
1525 /* Local address is added. */
1526 if (nhs != 1) {
1527 NL_SET_ERR_MSG(extack,
1528 "Route with host scope can not have multiple nexthops");
1529 goto err_inval;
1530 }
1531 if (nh->fib_nh_gw_family) {
1532 NL_SET_ERR_MSG(extack,
1533 "Route with host scope can not have a gateway");
1534 goto err_inval;
1535 }
1536 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1537 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1538 err = -ENODEV;
1539 if (!nh->fib_nh_dev)
1540 goto failure;
1541 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1542 GFP_KERNEL);
1543 } else {
1544 int linkdown = 0;
1545
1546 change_nexthops(fi) {
1547 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1548 cfg->fc_table, cfg->fc_scope,
1549 extack);
1550 if (err != 0)
1551 goto failure;
1552 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1553 linkdown++;
1554 } endfor_nexthops(fi)
1555 if (linkdown == fi->fib_nhs)
1556 fi->fib_flags |= RTNH_F_LINKDOWN;
1557 }
1558
1559 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1560 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1561 goto err_inval;
1562 }
1563
1564 if (!fi->nh) {
1565 change_nexthops(fi) {
1566 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1567 fi->fib_scope);
1568 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1569 fi->fib_nh_is_v6 = true;
1570 } endfor_nexthops(fi)
1571
1572 fib_rebalance(fi);
1573 }
1574
1575 link_it:
1576 ofi = fib_find_info(fi);
1577 if (ofi) {
1578 fi->fib_dead = 1;
1579 free_fib_info(fi);
1580 refcount_inc(&ofi->fib_treeref);
1581 return ofi;
1582 }
1583
1584 refcount_set(&fi->fib_treeref, 1);
1585 refcount_set(&fi->fib_clntref, 1);
1586 spin_lock_bh(&fib_info_lock);
1587 fib_info_cnt++;
1588 hlist_add_head(&fi->fib_hash,
1589 &fib_info_hash[fib_info_hashfn(fi)]);
1590 if (fi->fib_prefsrc) {
1591 struct hlist_head *head;
1592
1593 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc);
1594 hlist_add_head(&fi->fib_lhash, head);
1595 }
1596 if (fi->nh) {
1597 list_add(&fi->nh_list, &nh->fi_list);
1598 } else {
1599 change_nexthops(fi) {
1600 struct hlist_head *head;
1601
1602 if (!nexthop_nh->fib_nh_dev)
1603 continue;
1604 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
1605 hlist_add_head(&nexthop_nh->nh_hash, head);
1606 } endfor_nexthops(fi)
1607 }
1608 spin_unlock_bh(&fib_info_lock);
1609 return fi;
1610
1611 err_inval:
1612 err = -EINVAL;
1613
1614 failure:
1615 if (fi) {
1616 fi->fib_dead = 1;
1617 free_fib_info(fi);
1618 }
1619
1620 return ERR_PTR(err);
1621 }
1622
fib_nexthop_info(struct sk_buff * skb,const struct fib_nh_common * nhc,u8 rt_family,unsigned char * flags,bool skip_oif)1623 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1624 u8 rt_family, unsigned char *flags, bool skip_oif)
1625 {
1626 if (nhc->nhc_flags & RTNH_F_DEAD)
1627 *flags |= RTNH_F_DEAD;
1628
1629 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1630 *flags |= RTNH_F_LINKDOWN;
1631
1632 rcu_read_lock();
1633 switch (nhc->nhc_family) {
1634 case AF_INET:
1635 if (ip_ignore_linkdown(nhc->nhc_dev))
1636 *flags |= RTNH_F_DEAD;
1637 break;
1638 case AF_INET6:
1639 if (ip6_ignore_linkdown(nhc->nhc_dev))
1640 *flags |= RTNH_F_DEAD;
1641 break;
1642 }
1643 rcu_read_unlock();
1644 }
1645
1646 switch (nhc->nhc_gw_family) {
1647 case AF_INET:
1648 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1649 goto nla_put_failure;
1650 break;
1651 case AF_INET6:
1652 /* if gateway family does not match nexthop family
1653 * gateway is encoded as RTA_VIA
1654 */
1655 if (rt_family != nhc->nhc_gw_family) {
1656 int alen = sizeof(struct in6_addr);
1657 struct nlattr *nla;
1658 struct rtvia *via;
1659
1660 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1661 if (!nla)
1662 goto nla_put_failure;
1663
1664 via = nla_data(nla);
1665 via->rtvia_family = AF_INET6;
1666 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1667 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1668 &nhc->nhc_gw.ipv6) < 0) {
1669 goto nla_put_failure;
1670 }
1671 break;
1672 }
1673
1674 *flags |= (nhc->nhc_flags &
1675 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1676
1677 if (!skip_oif && nhc->nhc_dev &&
1678 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1679 goto nla_put_failure;
1680
1681 if (nhc->nhc_lwtstate &&
1682 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1683 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1684 goto nla_put_failure;
1685
1686 return 0;
1687
1688 nla_put_failure:
1689 return -EMSGSIZE;
1690 }
1691 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1692
1693 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
fib_add_nexthop(struct sk_buff * skb,const struct fib_nh_common * nhc,int nh_weight,u8 rt_family,u32 nh_tclassid)1694 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1695 int nh_weight, u8 rt_family, u32 nh_tclassid)
1696 {
1697 const struct net_device *dev = nhc->nhc_dev;
1698 struct rtnexthop *rtnh;
1699 unsigned char flags = 0;
1700
1701 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1702 if (!rtnh)
1703 goto nla_put_failure;
1704
1705 rtnh->rtnh_hops = nh_weight - 1;
1706 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1707
1708 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1709 goto nla_put_failure;
1710
1711 rtnh->rtnh_flags = flags;
1712
1713 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1714 goto nla_put_failure;
1715
1716 /* length of rtnetlink header + attributes */
1717 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1718
1719 return 0;
1720
1721 nla_put_failure:
1722 return -EMSGSIZE;
1723 }
1724 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1725 #endif
1726
1727 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1728 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1729 {
1730 struct nlattr *mp;
1731
1732 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1733 if (!mp)
1734 goto nla_put_failure;
1735
1736 if (unlikely(fi->nh)) {
1737 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1738 goto nla_put_failure;
1739 goto mp_end;
1740 }
1741
1742 for_nexthops(fi) {
1743 u32 nh_tclassid = 0;
1744 #ifdef CONFIG_IP_ROUTE_CLASSID
1745 nh_tclassid = nh->nh_tclassid;
1746 #endif
1747 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1748 AF_INET, nh_tclassid) < 0)
1749 goto nla_put_failure;
1750 } endfor_nexthops(fi);
1751
1752 mp_end:
1753 nla_nest_end(skb, mp);
1754
1755 return 0;
1756
1757 nla_put_failure:
1758 return -EMSGSIZE;
1759 }
1760 #else
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1761 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1762 {
1763 return 0;
1764 }
1765 #endif
1766
fib_dump_info(struct sk_buff * skb,u32 portid,u32 seq,int event,const struct fib_rt_info * fri,unsigned int flags)1767 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1768 const struct fib_rt_info *fri, unsigned int flags)
1769 {
1770 unsigned int nhs = fib_info_num_path(fri->fi);
1771 struct fib_info *fi = fri->fi;
1772 u32 tb_id = fri->tb_id;
1773 struct nlmsghdr *nlh;
1774 struct rtmsg *rtm;
1775
1776 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1777 if (!nlh)
1778 return -EMSGSIZE;
1779
1780 rtm = nlmsg_data(nlh);
1781 rtm->rtm_family = AF_INET;
1782 rtm->rtm_dst_len = fri->dst_len;
1783 rtm->rtm_src_len = 0;
1784 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp);
1785 if (tb_id < 256)
1786 rtm->rtm_table = tb_id;
1787 else
1788 rtm->rtm_table = RT_TABLE_COMPAT;
1789 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1790 goto nla_put_failure;
1791 rtm->rtm_type = fri->type;
1792 rtm->rtm_flags = fi->fib_flags;
1793 rtm->rtm_scope = fi->fib_scope;
1794 rtm->rtm_protocol = fi->fib_protocol;
1795
1796 if (rtm->rtm_dst_len &&
1797 nla_put_in_addr(skb, RTA_DST, fri->dst))
1798 goto nla_put_failure;
1799 if (fi->fib_priority &&
1800 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1801 goto nla_put_failure;
1802 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1803 goto nla_put_failure;
1804
1805 if (fi->fib_prefsrc &&
1806 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1807 goto nla_put_failure;
1808
1809 if (fi->nh) {
1810 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1811 goto nla_put_failure;
1812 if (nexthop_is_blackhole(fi->nh))
1813 rtm->rtm_type = RTN_BLACKHOLE;
1814 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
1815 goto offload;
1816 }
1817
1818 if (nhs == 1) {
1819 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1820 unsigned char flags = 0;
1821
1822 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1823 goto nla_put_failure;
1824
1825 rtm->rtm_flags = flags;
1826 #ifdef CONFIG_IP_ROUTE_CLASSID
1827 if (nhc->nhc_family == AF_INET) {
1828 struct fib_nh *nh;
1829
1830 nh = container_of(nhc, struct fib_nh, nh_common);
1831 if (nh->nh_tclassid &&
1832 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1833 goto nla_put_failure;
1834 }
1835 #endif
1836 } else {
1837 if (fib_add_multipath(skb, fi) < 0)
1838 goto nla_put_failure;
1839 }
1840
1841 offload:
1842 if (fri->offload)
1843 rtm->rtm_flags |= RTM_F_OFFLOAD;
1844 if (fri->trap)
1845 rtm->rtm_flags |= RTM_F_TRAP;
1846 if (fri->offload_failed)
1847 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1848
1849 nlmsg_end(skb, nlh);
1850 return 0;
1851
1852 nla_put_failure:
1853 nlmsg_cancel(skb, nlh);
1854 return -EMSGSIZE;
1855 }
1856
1857 /*
1858 * Update FIB if:
1859 * - local address disappeared -> we must delete all the entries
1860 * referring to it.
1861 * - device went down -> we must shutdown all nexthops going via it.
1862 */
fib_sync_down_addr(struct net_device * dev,__be32 local)1863 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1864 {
1865 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1866 struct net *net = dev_net(dev);
1867 struct hlist_head *head;
1868 struct fib_info *fi;
1869 int ret = 0;
1870
1871 if (!fib_info_laddrhash || local == 0)
1872 return 0;
1873
1874 head = fib_info_laddrhash_bucket(net, local);
1875 hlist_for_each_entry(fi, head, fib_lhash) {
1876 if (!net_eq(fi->fib_net, net) ||
1877 fi->fib_tb_id != tb_id)
1878 continue;
1879 if (fi->fib_prefsrc == local) {
1880 fi->fib_flags |= RTNH_F_DEAD;
1881 ret++;
1882 }
1883 }
1884 return ret;
1885 }
1886
call_fib_nh_notifiers(struct fib_nh * nh,enum fib_event_type event_type)1887 static int call_fib_nh_notifiers(struct fib_nh *nh,
1888 enum fib_event_type event_type)
1889 {
1890 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1891 struct fib_nh_notifier_info info = {
1892 .fib_nh = nh,
1893 };
1894
1895 switch (event_type) {
1896 case FIB_EVENT_NH_ADD:
1897 if (nh->fib_nh_flags & RTNH_F_DEAD)
1898 break;
1899 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1900 break;
1901 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1902 &info.info);
1903 case FIB_EVENT_NH_DEL:
1904 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1905 (nh->fib_nh_flags & RTNH_F_DEAD))
1906 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1907 event_type, &info.info);
1908 break;
1909 default:
1910 break;
1911 }
1912
1913 return NOTIFY_DONE;
1914 }
1915
1916 /* Update the PMTU of exceptions when:
1917 * - the new MTU of the first hop becomes smaller than the PMTU
1918 * - the old MTU was the same as the PMTU, and it limited discovery of
1919 * larger MTUs on the path. With that limit raised, we can now
1920 * discover larger MTUs
1921 * A special case is locked exceptions, for which the PMTU is smaller
1922 * than the minimal accepted PMTU:
1923 * - if the new MTU is greater than the PMTU, don't make any change
1924 * - otherwise, unlock and set PMTU
1925 */
fib_nhc_update_mtu(struct fib_nh_common * nhc,u32 new,u32 orig)1926 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1927 {
1928 struct fnhe_hash_bucket *bucket;
1929 int i;
1930
1931 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1932 if (!bucket)
1933 return;
1934
1935 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1936 struct fib_nh_exception *fnhe;
1937
1938 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1939 fnhe;
1940 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1941 if (fnhe->fnhe_mtu_locked) {
1942 if (new <= fnhe->fnhe_pmtu) {
1943 fnhe->fnhe_pmtu = new;
1944 fnhe->fnhe_mtu_locked = false;
1945 }
1946 } else if (new < fnhe->fnhe_pmtu ||
1947 orig == fnhe->fnhe_pmtu) {
1948 fnhe->fnhe_pmtu = new;
1949 }
1950 }
1951 }
1952 }
1953
fib_sync_mtu(struct net_device * dev,u32 orig_mtu)1954 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1955 {
1956 struct hlist_head *head = fib_info_devhash_bucket(dev);
1957 struct fib_nh *nh;
1958
1959 hlist_for_each_entry(nh, head, nh_hash) {
1960 if (nh->fib_nh_dev == dev)
1961 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1962 }
1963 }
1964
1965 /* Event force Flags Description
1966 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1967 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1968 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1969 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1970 *
1971 * only used when fib_nh is built into fib_info
1972 */
fib_sync_down_dev(struct net_device * dev,unsigned long event,bool force)1973 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1974 {
1975 struct hlist_head *head = fib_info_devhash_bucket(dev);
1976 struct fib_info *prev_fi = NULL;
1977 int scope = RT_SCOPE_NOWHERE;
1978 struct fib_nh *nh;
1979 int ret = 0;
1980
1981 if (force)
1982 scope = -1;
1983
1984 hlist_for_each_entry(nh, head, nh_hash) {
1985 struct fib_info *fi = nh->nh_parent;
1986 int dead;
1987
1988 BUG_ON(!fi->fib_nhs);
1989 if (nh->fib_nh_dev != dev || fi == prev_fi)
1990 continue;
1991 prev_fi = fi;
1992 dead = 0;
1993 change_nexthops(fi) {
1994 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1995 dead++;
1996 else if (nexthop_nh->fib_nh_dev == dev &&
1997 nexthop_nh->fib_nh_scope != scope) {
1998 switch (event) {
1999 case NETDEV_DOWN:
2000 case NETDEV_UNREGISTER:
2001 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
2002 fallthrough;
2003 case NETDEV_CHANGE:
2004 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
2005 break;
2006 }
2007 call_fib_nh_notifiers(nexthop_nh,
2008 FIB_EVENT_NH_DEL);
2009 dead++;
2010 }
2011 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2012 if (event == NETDEV_UNREGISTER &&
2013 nexthop_nh->fib_nh_dev == dev) {
2014 dead = fi->fib_nhs;
2015 break;
2016 }
2017 #endif
2018 } endfor_nexthops(fi)
2019 if (dead == fi->fib_nhs) {
2020 switch (event) {
2021 case NETDEV_DOWN:
2022 case NETDEV_UNREGISTER:
2023 fi->fib_flags |= RTNH_F_DEAD;
2024 fallthrough;
2025 case NETDEV_CHANGE:
2026 fi->fib_flags |= RTNH_F_LINKDOWN;
2027 break;
2028 }
2029 ret++;
2030 }
2031
2032 fib_rebalance(fi);
2033 }
2034
2035 return ret;
2036 }
2037
2038 /* Must be invoked inside of an RCU protected region. */
fib_select_default(const struct flowi4 * flp,struct fib_result * res)2039 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2040 {
2041 struct fib_info *fi = NULL, *last_resort = NULL;
2042 struct hlist_head *fa_head = res->fa_head;
2043 struct fib_table *tb = res->table;
2044 u8 slen = 32 - res->prefixlen;
2045 int order = -1, last_idx = -1;
2046 struct fib_alias *fa, *fa1 = NULL;
2047 u32 last_prio = res->fi->fib_priority;
2048 dscp_t last_dscp = 0;
2049
2050 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2051 struct fib_info *next_fi = fa->fa_info;
2052 struct fib_nh_common *nhc;
2053
2054 if (fa->fa_slen != slen)
2055 continue;
2056 if (fa->fa_dscp &&
2057 fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos))
2058 continue;
2059 if (fa->tb_id != tb->tb_id)
2060 continue;
2061 if (next_fi->fib_priority > last_prio &&
2062 fa->fa_dscp == last_dscp) {
2063 if (last_dscp)
2064 continue;
2065 break;
2066 }
2067 if (next_fi->fib_flags & RTNH_F_DEAD)
2068 continue;
2069 last_dscp = fa->fa_dscp;
2070 last_prio = next_fi->fib_priority;
2071
2072 if (next_fi->fib_scope != res->scope ||
2073 fa->fa_type != RTN_UNICAST)
2074 continue;
2075
2076 nhc = fib_info_nhc(next_fi, 0);
2077 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2078 continue;
2079
2080 fib_alias_accessed(fa);
2081
2082 if (!fi) {
2083 if (next_fi != res->fi)
2084 break;
2085 fa1 = fa;
2086 } else if (!fib_detect_death(fi, order, &last_resort,
2087 &last_idx, fa1->fa_default)) {
2088 fib_result_assign(res, fi);
2089 fa1->fa_default = order;
2090 goto out;
2091 }
2092 fi = next_fi;
2093 order++;
2094 }
2095
2096 if (order <= 0 || !fi) {
2097 if (fa1)
2098 fa1->fa_default = -1;
2099 goto out;
2100 }
2101
2102 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2103 fa1->fa_default)) {
2104 fib_result_assign(res, fi);
2105 fa1->fa_default = order;
2106 goto out;
2107 }
2108
2109 if (last_idx >= 0)
2110 fib_result_assign(res, last_resort);
2111 fa1->fa_default = last_idx;
2112 out:
2113 return;
2114 }
2115
2116 /*
2117 * Dead device goes up. We wake up dead nexthops.
2118 * It takes sense only on multipath routes.
2119 *
2120 * only used when fib_nh is built into fib_info
2121 */
fib_sync_up(struct net_device * dev,unsigned char nh_flags)2122 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2123 {
2124 struct fib_info *prev_fi;
2125 struct hlist_head *head;
2126 struct fib_nh *nh;
2127 int ret;
2128
2129 if (!(dev->flags & IFF_UP))
2130 return 0;
2131
2132 if (nh_flags & RTNH_F_DEAD) {
2133 unsigned int flags = dev_get_flags(dev);
2134
2135 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2136 nh_flags |= RTNH_F_LINKDOWN;
2137 }
2138
2139 prev_fi = NULL;
2140 head = fib_info_devhash_bucket(dev);
2141 ret = 0;
2142
2143 hlist_for_each_entry(nh, head, nh_hash) {
2144 struct fib_info *fi = nh->nh_parent;
2145 int alive;
2146
2147 BUG_ON(!fi->fib_nhs);
2148 if (nh->fib_nh_dev != dev || fi == prev_fi)
2149 continue;
2150
2151 prev_fi = fi;
2152 alive = 0;
2153 change_nexthops(fi) {
2154 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2155 alive++;
2156 continue;
2157 }
2158 if (!nexthop_nh->fib_nh_dev ||
2159 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2160 continue;
2161 if (nexthop_nh->fib_nh_dev != dev ||
2162 !__in_dev_get_rtnl(dev))
2163 continue;
2164 alive++;
2165 nexthop_nh->fib_nh_flags &= ~nh_flags;
2166 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2167 } endfor_nexthops(fi)
2168
2169 if (alive > 0) {
2170 fi->fib_flags &= ~nh_flags;
2171 ret++;
2172 }
2173
2174 fib_rebalance(fi);
2175 }
2176
2177 return ret;
2178 }
2179
2180 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_good_nh(const struct fib_nh * nh)2181 static bool fib_good_nh(const struct fib_nh *nh)
2182 {
2183 int state = NUD_REACHABLE;
2184
2185 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2186 struct neighbour *n;
2187
2188 rcu_read_lock_bh();
2189
2190 if (likely(nh->fib_nh_gw_family == AF_INET))
2191 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2192 (__force u32)nh->fib_nh_gw4);
2193 else if (nh->fib_nh_gw_family == AF_INET6)
2194 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2195 &nh->fib_nh_gw6);
2196 else
2197 n = NULL;
2198 if (n)
2199 state = n->nud_state;
2200
2201 rcu_read_unlock_bh();
2202 }
2203
2204 return !!(state & NUD_VALID);
2205 }
2206
fib_select_multipath(struct fib_result * res,int hash)2207 void fib_select_multipath(struct fib_result *res, int hash)
2208 {
2209 struct fib_info *fi = res->fi;
2210 struct net *net = fi->fib_net;
2211 bool first = false;
2212
2213 if (unlikely(res->fi->nh)) {
2214 nexthop_path_fib_result(res, hash);
2215 return;
2216 }
2217
2218 change_nexthops(fi) {
2219 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) {
2220 if (!fib_good_nh(nexthop_nh))
2221 continue;
2222 if (!first) {
2223 res->nh_sel = nhsel;
2224 res->nhc = &nexthop_nh->nh_common;
2225 first = true;
2226 }
2227 }
2228
2229 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2230 continue;
2231
2232 res->nh_sel = nhsel;
2233 res->nhc = &nexthop_nh->nh_common;
2234 return;
2235 } endfor_nexthops(fi);
2236 }
2237 #endif
2238
fib_select_path(struct net * net,struct fib_result * res,struct flowi4 * fl4,const struct sk_buff * skb)2239 void fib_select_path(struct net *net, struct fib_result *res,
2240 struct flowi4 *fl4, const struct sk_buff *skb)
2241 {
2242 if (fl4->flowi4_oif)
2243 goto check_saddr;
2244
2245 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2246 if (fib_info_num_path(res->fi) > 1) {
2247 int h = fib_multipath_hash(net, fl4, skb, NULL);
2248
2249 fib_select_multipath(res, h);
2250 }
2251 else
2252 #endif
2253 if (!res->prefixlen &&
2254 res->table->tb_num_default > 1 &&
2255 res->type == RTN_UNICAST)
2256 fib_select_default(fl4, res);
2257
2258 check_saddr:
2259 if (!fl4->saddr)
2260 fl4->saddr = fib_result_prefsrc(net, res);
2261 }
2262