1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: semantics.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/uaccess.h>
13 #include <linux/bitops.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/jiffies.h>
17 #include <linux/mm.h>
18 #include <linux/string.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/errno.h>
22 #include <linux/in.h>
23 #include <linux/inet.h>
24 #include <linux/inetdevice.h>
25 #include <linux/netdevice.h>
26 #include <linux/if_arp.h>
27 #include <linux/proc_fs.h>
28 #include <linux/skbuff.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/netlink.h>
32 #include <linux/hash.h>
33 #include <linux/nospec.h>
34
35 #include <net/arp.h>
36 #include <net/ip.h>
37 #include <net/protocol.h>
38 #include <net/route.h>
39 #include <net/tcp.h>
40 #include <net/sock.h>
41 #include <net/ip_fib.h>
42 #include <net/ip6_fib.h>
43 #include <net/nexthop.h>
44 #include <net/netlink.h>
45 #include <net/rtnh.h>
46 #include <net/lwtunnel.h>
47 #include <net/fib_notifier.h>
48 #include <net/addrconf.h>
49
50 #include "fib_lookup.h"
51
52 static DEFINE_SPINLOCK(fib_info_lock);
53 static struct hlist_head *fib_info_hash;
54 static struct hlist_head *fib_info_laddrhash;
55 static unsigned int fib_info_hash_size;
56 static unsigned int fib_info_cnt;
57
58 #define DEVINDEX_HASHBITS 8
59 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
60 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
61
62 /* for_nexthops and change_nexthops only used when nexthop object
63 * is not set in a fib_info. The logic within can reference fib_nh.
64 */
65 #ifdef CONFIG_IP_ROUTE_MULTIPATH
66
67 #define for_nexthops(fi) { \
68 int nhsel; const struct fib_nh *nh; \
69 for (nhsel = 0, nh = (fi)->fib_nh; \
70 nhsel < fib_info_num_path((fi)); \
71 nh++, nhsel++)
72
73 #define change_nexthops(fi) { \
74 int nhsel; struct fib_nh *nexthop_nh; \
75 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
76 nhsel < fib_info_num_path((fi)); \
77 nexthop_nh++, nhsel++)
78
79 #else /* CONFIG_IP_ROUTE_MULTIPATH */
80
81 /* Hope, that gcc will optimize it to get rid of dummy loop */
82
83 #define for_nexthops(fi) { \
84 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87 #define change_nexthops(fi) { \
88 int nhsel; \
89 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
90 for (nhsel = 0; nhsel < 1; nhsel++)
91
92 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
93
94 #define endfor_nexthops(fi) }
95
96
97 const struct fib_prop fib_props[RTN_MAX + 1] = {
98 [RTN_UNSPEC] = {
99 .error = 0,
100 .scope = RT_SCOPE_NOWHERE,
101 },
102 [RTN_UNICAST] = {
103 .error = 0,
104 .scope = RT_SCOPE_UNIVERSE,
105 },
106 [RTN_LOCAL] = {
107 .error = 0,
108 .scope = RT_SCOPE_HOST,
109 },
110 [RTN_BROADCAST] = {
111 .error = 0,
112 .scope = RT_SCOPE_LINK,
113 },
114 [RTN_ANYCAST] = {
115 .error = 0,
116 .scope = RT_SCOPE_LINK,
117 },
118 [RTN_MULTICAST] = {
119 .error = 0,
120 .scope = RT_SCOPE_UNIVERSE,
121 },
122 [RTN_BLACKHOLE] = {
123 .error = -EINVAL,
124 .scope = RT_SCOPE_UNIVERSE,
125 },
126 [RTN_UNREACHABLE] = {
127 .error = -EHOSTUNREACH,
128 .scope = RT_SCOPE_UNIVERSE,
129 },
130 [RTN_PROHIBIT] = {
131 .error = -EACCES,
132 .scope = RT_SCOPE_UNIVERSE,
133 },
134 [RTN_THROW] = {
135 .error = -EAGAIN,
136 .scope = RT_SCOPE_UNIVERSE,
137 },
138 [RTN_NAT] = {
139 .error = -EINVAL,
140 .scope = RT_SCOPE_NOWHERE,
141 },
142 [RTN_XRESOLVE] = {
143 .error = -EINVAL,
144 .scope = RT_SCOPE_NOWHERE,
145 },
146 };
147
rt_fibinfo_free(struct rtable __rcu ** rtp)148 static void rt_fibinfo_free(struct rtable __rcu **rtp)
149 {
150 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
151
152 if (!rt)
153 return;
154
155 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
156 * because we waited an RCU grace period before calling
157 * free_fib_info_rcu()
158 */
159
160 dst_dev_put(&rt->dst);
161 dst_release_immediate(&rt->dst);
162 }
163
free_nh_exceptions(struct fib_nh_common * nhc)164 static void free_nh_exceptions(struct fib_nh_common *nhc)
165 {
166 struct fnhe_hash_bucket *hash;
167 int i;
168
169 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
170 if (!hash)
171 return;
172 for (i = 0; i < FNHE_HASH_SIZE; i++) {
173 struct fib_nh_exception *fnhe;
174
175 fnhe = rcu_dereference_protected(hash[i].chain, 1);
176 while (fnhe) {
177 struct fib_nh_exception *next;
178
179 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
180
181 rt_fibinfo_free(&fnhe->fnhe_rth_input);
182 rt_fibinfo_free(&fnhe->fnhe_rth_output);
183
184 kfree(fnhe);
185
186 fnhe = next;
187 }
188 }
189 kfree(hash);
190 }
191
rt_fibinfo_free_cpus(struct rtable __rcu * __percpu * rtp)192 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
193 {
194 int cpu;
195
196 if (!rtp)
197 return;
198
199 for_each_possible_cpu(cpu) {
200 struct rtable *rt;
201
202 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
203 if (rt) {
204 dst_dev_put(&rt->dst);
205 dst_release_immediate(&rt->dst);
206 }
207 }
208 free_percpu(rtp);
209 }
210
fib_nh_common_release(struct fib_nh_common * nhc)211 void fib_nh_common_release(struct fib_nh_common *nhc)
212 {
213 if (nhc->nhc_dev)
214 dev_put(nhc->nhc_dev);
215
216 lwtstate_put(nhc->nhc_lwtstate);
217 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
218 rt_fibinfo_free(&nhc->nhc_rth_input);
219 free_nh_exceptions(nhc);
220 }
221 EXPORT_SYMBOL_GPL(fib_nh_common_release);
222
fib_nh_release(struct net * net,struct fib_nh * fib_nh)223 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
224 {
225 #ifdef CONFIG_IP_ROUTE_CLASSID
226 if (fib_nh->nh_tclassid)
227 atomic_dec(&net->ipv4.fib_num_tclassid_users);
228 #endif
229 fib_nh_common_release(&fib_nh->nh_common);
230 }
231
232 /* Release a nexthop info record */
free_fib_info_rcu(struct rcu_head * head)233 static void free_fib_info_rcu(struct rcu_head *head)
234 {
235 struct fib_info *fi = container_of(head, struct fib_info, rcu);
236
237 if (fi->nh) {
238 nexthop_put(fi->nh);
239 } else {
240 change_nexthops(fi) {
241 fib_nh_release(fi->fib_net, nexthop_nh);
242 } endfor_nexthops(fi);
243 }
244
245 ip_fib_metrics_put(fi->fib_metrics);
246
247 kfree(fi);
248 }
249
free_fib_info(struct fib_info * fi)250 void free_fib_info(struct fib_info *fi)
251 {
252 if (fi->fib_dead == 0) {
253 pr_warn("Freeing alive fib_info %p\n", fi);
254 return;
255 }
256
257 call_rcu(&fi->rcu, free_fib_info_rcu);
258 }
259 EXPORT_SYMBOL_GPL(free_fib_info);
260
fib_release_info(struct fib_info * fi)261 void fib_release_info(struct fib_info *fi)
262 {
263 spin_lock_bh(&fib_info_lock);
264 if (fi && --fi->fib_treeref == 0) {
265 hlist_del(&fi->fib_hash);
266
267 /* Paired with READ_ONCE() in fib_create_info(). */
268 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
269
270 if (fi->fib_prefsrc)
271 hlist_del(&fi->fib_lhash);
272 if (fi->nh) {
273 list_del(&fi->nh_list);
274 } else {
275 change_nexthops(fi) {
276 if (!nexthop_nh->fib_nh_dev)
277 continue;
278 hlist_del(&nexthop_nh->nh_hash);
279 } endfor_nexthops(fi)
280 }
281 /* Paired with READ_ONCE() from fib_table_lookup() */
282 WRITE_ONCE(fi->fib_dead, 1);
283 fib_info_put(fi);
284 }
285 spin_unlock_bh(&fib_info_lock);
286 }
287
nh_comp(struct fib_info * fi,struct fib_info * ofi)288 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
289 {
290 const struct fib_nh *onh;
291
292 if (fi->nh || ofi->nh)
293 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
294
295 if (ofi->fib_nhs == 0)
296 return 0;
297
298 for_nexthops(fi) {
299 onh = fib_info_nh(ofi, nhsel);
300
301 if (nh->fib_nh_oif != onh->fib_nh_oif ||
302 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
303 nh->fib_nh_scope != onh->fib_nh_scope ||
304 #ifdef CONFIG_IP_ROUTE_MULTIPATH
305 nh->fib_nh_weight != onh->fib_nh_weight ||
306 #endif
307 #ifdef CONFIG_IP_ROUTE_CLASSID
308 nh->nh_tclassid != onh->nh_tclassid ||
309 #endif
310 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
311 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
312 return -1;
313
314 if (nh->fib_nh_gw_family == AF_INET &&
315 nh->fib_nh_gw4 != onh->fib_nh_gw4)
316 return -1;
317
318 if (nh->fib_nh_gw_family == AF_INET6 &&
319 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
320 return -1;
321 } endfor_nexthops(fi);
322 return 0;
323 }
324
fib_devindex_hashfn(unsigned int val)325 static inline unsigned int fib_devindex_hashfn(unsigned int val)
326 {
327 return hash_32(val, DEVINDEX_HASHBITS);
328 }
329
330 static struct hlist_head *
fib_info_devhash_bucket(const struct net_device * dev)331 fib_info_devhash_bucket(const struct net_device *dev)
332 {
333 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
334
335 return &fib_info_devhash[fib_devindex_hashfn(val)];
336 }
337
fib_info_hashfn_1(int init_val,u8 protocol,u8 scope,u32 prefsrc,u32 priority)338 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
339 u32 prefsrc, u32 priority)
340 {
341 unsigned int val = init_val;
342
343 val ^= (protocol << 8) | scope;
344 val ^= prefsrc;
345 val ^= priority;
346
347 return val;
348 }
349
fib_info_hashfn_result(unsigned int val)350 static unsigned int fib_info_hashfn_result(unsigned int val)
351 {
352 unsigned int mask = (fib_info_hash_size - 1);
353
354 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
355 }
356
fib_info_hashfn(struct fib_info * fi)357 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
358 {
359 unsigned int val;
360
361 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
362 fi->fib_scope, (__force u32)fi->fib_prefsrc,
363 fi->fib_priority);
364
365 if (fi->nh) {
366 val ^= fib_devindex_hashfn(fi->nh->id);
367 } else {
368 for_nexthops(fi) {
369 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
370 } endfor_nexthops(fi)
371 }
372
373 return fib_info_hashfn_result(val);
374 }
375
376 /* no metrics, only nexthop id */
fib_find_info_nh(struct net * net,const struct fib_config * cfg)377 static struct fib_info *fib_find_info_nh(struct net *net,
378 const struct fib_config *cfg)
379 {
380 struct hlist_head *head;
381 struct fib_info *fi;
382 unsigned int hash;
383
384 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
385 cfg->fc_protocol, cfg->fc_scope,
386 (__force u32)cfg->fc_prefsrc,
387 cfg->fc_priority);
388 hash = fib_info_hashfn_result(hash);
389 head = &fib_info_hash[hash];
390
391 hlist_for_each_entry(fi, head, fib_hash) {
392 if (!net_eq(fi->fib_net, net))
393 continue;
394 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
395 continue;
396 if (cfg->fc_protocol == fi->fib_protocol &&
397 cfg->fc_scope == fi->fib_scope &&
398 cfg->fc_prefsrc == fi->fib_prefsrc &&
399 cfg->fc_priority == fi->fib_priority &&
400 cfg->fc_type == fi->fib_type &&
401 cfg->fc_table == fi->fib_tb_id &&
402 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
403 return fi;
404 }
405
406 return NULL;
407 }
408
fib_find_info(struct fib_info * nfi)409 static struct fib_info *fib_find_info(struct fib_info *nfi)
410 {
411 struct hlist_head *head;
412 struct fib_info *fi;
413 unsigned int hash;
414
415 hash = fib_info_hashfn(nfi);
416 head = &fib_info_hash[hash];
417
418 hlist_for_each_entry(fi, head, fib_hash) {
419 if (!net_eq(fi->fib_net, nfi->fib_net))
420 continue;
421 if (fi->fib_nhs != nfi->fib_nhs)
422 continue;
423 if (nfi->fib_protocol == fi->fib_protocol &&
424 nfi->fib_scope == fi->fib_scope &&
425 nfi->fib_prefsrc == fi->fib_prefsrc &&
426 nfi->fib_priority == fi->fib_priority &&
427 nfi->fib_type == fi->fib_type &&
428 nfi->fib_tb_id == fi->fib_tb_id &&
429 memcmp(nfi->fib_metrics, fi->fib_metrics,
430 sizeof(u32) * RTAX_MAX) == 0 &&
431 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
432 nh_comp(fi, nfi) == 0)
433 return fi;
434 }
435
436 return NULL;
437 }
438
439 /* Check, that the gateway is already configured.
440 * Used only by redirect accept routine.
441 */
ip_fib_check_default(__be32 gw,struct net_device * dev)442 int ip_fib_check_default(__be32 gw, struct net_device *dev)
443 {
444 struct hlist_head *head;
445 struct fib_nh *nh;
446
447 spin_lock(&fib_info_lock);
448
449 head = fib_info_devhash_bucket(dev);
450
451 hlist_for_each_entry(nh, head, nh_hash) {
452 if (nh->fib_nh_dev == dev &&
453 nh->fib_nh_gw4 == gw &&
454 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
455 spin_unlock(&fib_info_lock);
456 return 0;
457 }
458 }
459
460 spin_unlock(&fib_info_lock);
461
462 return -1;
463 }
464
fib_nlmsg_size(struct fib_info * fi)465 static inline size_t fib_nlmsg_size(struct fib_info *fi)
466 {
467 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
468 + nla_total_size(4) /* RTA_TABLE */
469 + nla_total_size(4) /* RTA_DST */
470 + nla_total_size(4) /* RTA_PRIORITY */
471 + nla_total_size(4) /* RTA_PREFSRC */
472 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
473 unsigned int nhs = fib_info_num_path(fi);
474
475 /* space for nested metrics */
476 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
477
478 if (fi->nh)
479 payload += nla_total_size(4); /* RTA_NH_ID */
480
481 if (nhs) {
482 size_t nh_encapsize = 0;
483 /* Also handles the special case nhs == 1 */
484
485 /* each nexthop is packed in an attribute */
486 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
487 unsigned int i;
488
489 /* may contain flow and gateway attribute */
490 nhsize += 2 * nla_total_size(4);
491
492 /* grab encap info */
493 for (i = 0; i < fib_info_num_path(fi); i++) {
494 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
495
496 if (nhc->nhc_lwtstate) {
497 /* RTA_ENCAP_TYPE */
498 nh_encapsize += lwtunnel_get_encap_size(
499 nhc->nhc_lwtstate);
500 /* RTA_ENCAP */
501 nh_encapsize += nla_total_size(2);
502 }
503 }
504
505 /* all nexthops are packed in a nested attribute */
506 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
507
508 }
509
510 return payload;
511 }
512
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)513 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
514 int dst_len, u32 tb_id, const struct nl_info *info,
515 unsigned int nlm_flags)
516 {
517 struct fib_rt_info fri;
518 struct sk_buff *skb;
519 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
520 int err = -ENOBUFS;
521
522 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
523 if (!skb)
524 goto errout;
525
526 fri.fi = fa->fa_info;
527 fri.tb_id = tb_id;
528 fri.dst = key;
529 fri.dst_len = dst_len;
530 fri.tos = fa->fa_tos;
531 fri.type = fa->fa_type;
532 fri.offload = fa->offload;
533 fri.trap = fa->trap;
534 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
535 if (err < 0) {
536 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
537 WARN_ON(err == -EMSGSIZE);
538 kfree_skb(skb);
539 goto errout;
540 }
541 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
542 info->nlh, GFP_KERNEL);
543 return;
544 errout:
545 if (err < 0)
546 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
547 }
548
fib_detect_death(struct fib_info * fi,int order,struct fib_info ** last_resort,int * last_idx,int dflt)549 static int fib_detect_death(struct fib_info *fi, int order,
550 struct fib_info **last_resort, int *last_idx,
551 int dflt)
552 {
553 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
554 struct neighbour *n;
555 int state = NUD_NONE;
556
557 if (likely(nhc->nhc_gw_family == AF_INET))
558 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
559 else if (nhc->nhc_gw_family == AF_INET6)
560 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
561 nhc->nhc_dev);
562 else
563 n = NULL;
564
565 if (n) {
566 state = n->nud_state;
567 neigh_release(n);
568 } else {
569 return 0;
570 }
571 if (state == NUD_REACHABLE)
572 return 0;
573 if ((state & NUD_VALID) && order != dflt)
574 return 0;
575 if ((state & NUD_VALID) ||
576 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
577 *last_resort = fi;
578 *last_idx = order;
579 }
580 return 1;
581 }
582
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)583 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
584 struct nlattr *encap, u16 encap_type,
585 void *cfg, gfp_t gfp_flags,
586 struct netlink_ext_ack *extack)
587 {
588 int err;
589
590 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
591 gfp_flags);
592 if (!nhc->nhc_pcpu_rth_output)
593 return -ENOMEM;
594
595 if (encap) {
596 struct lwtunnel_state *lwtstate;
597
598 if (encap_type == LWTUNNEL_ENCAP_NONE) {
599 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
600 err = -EINVAL;
601 goto lwt_failure;
602 }
603 err = lwtunnel_build_state(net, encap_type, encap,
604 nhc->nhc_family, cfg, &lwtstate,
605 extack);
606 if (err)
607 goto lwt_failure;
608
609 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
610 }
611
612 return 0;
613
614 lwt_failure:
615 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
616 nhc->nhc_pcpu_rth_output = NULL;
617 return err;
618 }
619 EXPORT_SYMBOL_GPL(fib_nh_common_init);
620
fib_nh_init(struct net * net,struct fib_nh * nh,struct fib_config * cfg,int nh_weight,struct netlink_ext_ack * extack)621 int fib_nh_init(struct net *net, struct fib_nh *nh,
622 struct fib_config *cfg, int nh_weight,
623 struct netlink_ext_ack *extack)
624 {
625 int err;
626
627 nh->fib_nh_family = AF_INET;
628
629 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
630 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
631 if (err)
632 return err;
633
634 nh->fib_nh_oif = cfg->fc_oif;
635 nh->fib_nh_gw_family = cfg->fc_gw_family;
636 if (cfg->fc_gw_family == AF_INET)
637 nh->fib_nh_gw4 = cfg->fc_gw4;
638 else if (cfg->fc_gw_family == AF_INET6)
639 nh->fib_nh_gw6 = cfg->fc_gw6;
640
641 nh->fib_nh_flags = cfg->fc_flags;
642
643 #ifdef CONFIG_IP_ROUTE_CLASSID
644 nh->nh_tclassid = cfg->fc_flow;
645 if (nh->nh_tclassid)
646 atomic_inc(&net->ipv4.fib_num_tclassid_users);
647 #endif
648 #ifdef CONFIG_IP_ROUTE_MULTIPATH
649 nh->fib_nh_weight = nh_weight;
650 #endif
651 return 0;
652 }
653
654 #ifdef CONFIG_IP_ROUTE_MULTIPATH
655
fib_count_nexthops(struct rtnexthop * rtnh,int remaining,struct netlink_ext_ack * extack)656 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
657 struct netlink_ext_ack *extack)
658 {
659 int nhs = 0;
660
661 while (rtnh_ok(rtnh, remaining)) {
662 nhs++;
663 rtnh = rtnh_next(rtnh, &remaining);
664 }
665
666 /* leftover implies invalid nexthop configuration, discard it */
667 if (remaining > 0) {
668 NL_SET_ERR_MSG(extack,
669 "Invalid nexthop configuration - extra data after nexthops");
670 nhs = 0;
671 }
672
673 return nhs;
674 }
675
fib_gw_from_attr(__be32 * gw,struct nlattr * nla,struct netlink_ext_ack * extack)676 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
677 struct netlink_ext_ack *extack)
678 {
679 if (nla_len(nla) < sizeof(*gw)) {
680 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
681 return -EINVAL;
682 }
683
684 *gw = nla_get_in_addr(nla);
685
686 return 0;
687 }
688
689 /* 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)690 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
691 int remaining, struct fib_config *cfg,
692 struct netlink_ext_ack *extack)
693 {
694 struct net *net = fi->fib_net;
695 struct fib_config fib_cfg;
696 struct fib_nh *nh;
697 int ret;
698
699 change_nexthops(fi) {
700 int attrlen;
701
702 memset(&fib_cfg, 0, sizeof(fib_cfg));
703
704 if (!rtnh_ok(rtnh, remaining)) {
705 NL_SET_ERR_MSG(extack,
706 "Invalid nexthop configuration - extra data after nexthop");
707 return -EINVAL;
708 }
709
710 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
711 NL_SET_ERR_MSG(extack,
712 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
713 return -EINVAL;
714 }
715
716 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
717 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
718
719 attrlen = rtnh_attrlen(rtnh);
720 if (attrlen > 0) {
721 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
722
723 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
724 nlav = nla_find(attrs, attrlen, RTA_VIA);
725 if (nla && nlav) {
726 NL_SET_ERR_MSG(extack,
727 "Nexthop configuration can not contain both GATEWAY and VIA");
728 return -EINVAL;
729 }
730 if (nla) {
731 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
732 extack);
733 if (ret)
734 goto errout;
735
736 if (fib_cfg.fc_gw4)
737 fib_cfg.fc_gw_family = AF_INET;
738 } else if (nlav) {
739 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
740 if (ret)
741 goto errout;
742 }
743
744 nla = nla_find(attrs, attrlen, RTA_FLOW);
745 if (nla) {
746 if (nla_len(nla) < sizeof(u32)) {
747 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
748 return -EINVAL;
749 }
750 fib_cfg.fc_flow = nla_get_u32(nla);
751 }
752
753 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
754 /* RTA_ENCAP_TYPE length checked in
755 * lwtunnel_valid_encap_type_attr
756 */
757 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
758 if (nla)
759 fib_cfg.fc_encap_type = nla_get_u16(nla);
760 }
761
762 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
763 rtnh->rtnh_hops + 1, extack);
764 if (ret)
765 goto errout;
766
767 rtnh = rtnh_next(rtnh, &remaining);
768 } endfor_nexthops(fi);
769
770 ret = -EINVAL;
771 nh = fib_info_nh(fi, 0);
772 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
773 NL_SET_ERR_MSG(extack,
774 "Nexthop device index does not match RTA_OIF");
775 goto errout;
776 }
777 if (cfg->fc_gw_family) {
778 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
779 (cfg->fc_gw_family == AF_INET &&
780 nh->fib_nh_gw4 != cfg->fc_gw4) ||
781 (cfg->fc_gw_family == AF_INET6 &&
782 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
783 NL_SET_ERR_MSG(extack,
784 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
785 goto errout;
786 }
787 }
788 #ifdef CONFIG_IP_ROUTE_CLASSID
789 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
790 NL_SET_ERR_MSG(extack,
791 "Nexthop class id does not match RTA_FLOW");
792 goto errout;
793 }
794 #endif
795 ret = 0;
796 errout:
797 return ret;
798 }
799
800 /* only called when fib_nh is integrated into fib_info */
fib_rebalance(struct fib_info * fi)801 static void fib_rebalance(struct fib_info *fi)
802 {
803 int total;
804 int w;
805
806 if (fib_info_num_path(fi) < 2)
807 return;
808
809 total = 0;
810 for_nexthops(fi) {
811 if (nh->fib_nh_flags & RTNH_F_DEAD)
812 continue;
813
814 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
815 nh->fib_nh_flags & RTNH_F_LINKDOWN)
816 continue;
817
818 total += nh->fib_nh_weight;
819 } endfor_nexthops(fi);
820
821 w = 0;
822 change_nexthops(fi) {
823 int upper_bound;
824
825 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
826 upper_bound = -1;
827 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
828 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
829 upper_bound = -1;
830 } else {
831 w += nexthop_nh->fib_nh_weight;
832 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
833 total) - 1;
834 }
835
836 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
837 } endfor_nexthops(fi);
838 }
839 #else /* CONFIG_IP_ROUTE_MULTIPATH */
840
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)841 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
842 int remaining, struct fib_config *cfg,
843 struct netlink_ext_ack *extack)
844 {
845 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
846
847 return -EINVAL;
848 }
849
850 #define fib_rebalance(fi) do { } while (0)
851
852 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
853
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)854 static int fib_encap_match(struct net *net, u16 encap_type,
855 struct nlattr *encap,
856 const struct fib_nh *nh,
857 const struct fib_config *cfg,
858 struct netlink_ext_ack *extack)
859 {
860 struct lwtunnel_state *lwtstate;
861 int ret, result = 0;
862
863 if (encap_type == LWTUNNEL_ENCAP_NONE)
864 return 0;
865
866 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
867 cfg, &lwtstate, extack);
868 if (!ret) {
869 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
870 lwtstate_free(lwtstate);
871 }
872
873 return result;
874 }
875
fib_nh_match(struct net * net,struct fib_config * cfg,struct fib_info * fi,struct netlink_ext_ack * extack)876 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
877 struct netlink_ext_ack *extack)
878 {
879 #ifdef CONFIG_IP_ROUTE_MULTIPATH
880 struct rtnexthop *rtnh;
881 int remaining;
882 #endif
883
884 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
885 return 1;
886
887 if (cfg->fc_nh_id) {
888 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
889 return 0;
890 return 1;
891 }
892
893 if (fi->nh) {
894 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
895 return 1;
896 return 0;
897 }
898
899 if (cfg->fc_oif || cfg->fc_gw_family) {
900 struct fib_nh *nh;
901
902 nh = fib_info_nh(fi, 0);
903 if (cfg->fc_encap) {
904 if (fib_encap_match(net, cfg->fc_encap_type,
905 cfg->fc_encap, nh, cfg, extack))
906 return 1;
907 }
908 #ifdef CONFIG_IP_ROUTE_CLASSID
909 if (cfg->fc_flow &&
910 cfg->fc_flow != nh->nh_tclassid)
911 return 1;
912 #endif
913 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
914 (cfg->fc_gw_family &&
915 cfg->fc_gw_family != nh->fib_nh_gw_family))
916 return 1;
917
918 if (cfg->fc_gw_family == AF_INET &&
919 cfg->fc_gw4 != nh->fib_nh_gw4)
920 return 1;
921
922 if (cfg->fc_gw_family == AF_INET6 &&
923 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
924 return 1;
925
926 return 0;
927 }
928
929 #ifdef CONFIG_IP_ROUTE_MULTIPATH
930 if (!cfg->fc_mp)
931 return 0;
932
933 rtnh = cfg->fc_mp;
934 remaining = cfg->fc_mp_len;
935
936 for_nexthops(fi) {
937 int attrlen;
938
939 if (!rtnh_ok(rtnh, remaining))
940 return -EINVAL;
941
942 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
943 return 1;
944
945 attrlen = rtnh_attrlen(rtnh);
946 if (attrlen > 0) {
947 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
948 int err;
949
950 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
951 nlav = nla_find(attrs, attrlen, RTA_VIA);
952 if (nla && nlav) {
953 NL_SET_ERR_MSG(extack,
954 "Nexthop configuration can not contain both GATEWAY and VIA");
955 return -EINVAL;
956 }
957
958 if (nla) {
959 __be32 gw;
960
961 err = fib_gw_from_attr(&gw, nla, extack);
962 if (err)
963 return err;
964
965 if (nh->fib_nh_gw_family != AF_INET ||
966 gw != nh->fib_nh_gw4)
967 return 1;
968 } else if (nlav) {
969 struct fib_config cfg2;
970
971 err = fib_gw_from_via(&cfg2, nlav, extack);
972 if (err)
973 return err;
974
975 switch (nh->fib_nh_gw_family) {
976 case AF_INET:
977 if (cfg2.fc_gw_family != AF_INET ||
978 cfg2.fc_gw4 != nh->fib_nh_gw4)
979 return 1;
980 break;
981 case AF_INET6:
982 if (cfg2.fc_gw_family != AF_INET6 ||
983 ipv6_addr_cmp(&cfg2.fc_gw6,
984 &nh->fib_nh_gw6))
985 return 1;
986 break;
987 }
988 }
989
990 #ifdef CONFIG_IP_ROUTE_CLASSID
991 nla = nla_find(attrs, attrlen, RTA_FLOW);
992 if (nla) {
993 if (nla_len(nla) < sizeof(u32)) {
994 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
995 return -EINVAL;
996 }
997 if (nla_get_u32(nla) != nh->nh_tclassid)
998 return 1;
999 }
1000 #endif
1001 }
1002
1003 rtnh = rtnh_next(rtnh, &remaining);
1004 } endfor_nexthops(fi);
1005 #endif
1006 return 0;
1007 }
1008
fib_metrics_match(struct fib_config * cfg,struct fib_info * fi)1009 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1010 {
1011 struct nlattr *nla;
1012 int remaining;
1013
1014 if (!cfg->fc_mx)
1015 return true;
1016
1017 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1018 int type = nla_type(nla);
1019 u32 fi_val, val;
1020
1021 if (!type)
1022 continue;
1023 if (type > RTAX_MAX)
1024 return false;
1025
1026 type = array_index_nospec(type, RTAX_MAX + 1);
1027 if (type == RTAX_CC_ALGO) {
1028 char tmp[TCP_CA_NAME_MAX];
1029 bool ecn_ca = false;
1030
1031 nla_strlcpy(tmp, nla, sizeof(tmp));
1032 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1033 } else {
1034 if (nla_len(nla) != sizeof(u32))
1035 return false;
1036 val = nla_get_u32(nla);
1037 }
1038
1039 fi_val = fi->fib_metrics->metrics[type - 1];
1040 if (type == RTAX_FEATURES)
1041 fi_val &= ~DST_FEATURE_ECN_CA;
1042
1043 if (fi_val != val)
1044 return false;
1045 }
1046
1047 return true;
1048 }
1049
fib_check_nh_v6_gw(struct net * net,struct fib_nh * nh,u32 table,struct netlink_ext_ack * extack)1050 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1051 u32 table, struct netlink_ext_ack *extack)
1052 {
1053 struct fib6_config cfg = {
1054 .fc_table = table,
1055 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1056 .fc_ifindex = nh->fib_nh_oif,
1057 .fc_gateway = nh->fib_nh_gw6,
1058 };
1059 struct fib6_nh fib6_nh = {};
1060 int err;
1061
1062 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1063 if (!err) {
1064 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1065 dev_hold(nh->fib_nh_dev);
1066 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1067 nh->fib_nh_scope = RT_SCOPE_LINK;
1068
1069 ipv6_stub->fib6_nh_release(&fib6_nh);
1070 }
1071
1072 return err;
1073 }
1074
1075 /*
1076 * Picture
1077 * -------
1078 *
1079 * Semantics of nexthop is very messy by historical reasons.
1080 * We have to take into account, that:
1081 * a) gateway can be actually local interface address,
1082 * so that gatewayed route is direct.
1083 * b) gateway must be on-link address, possibly
1084 * described not by an ifaddr, but also by a direct route.
1085 * c) If both gateway and interface are specified, they should not
1086 * contradict.
1087 * d) If we use tunnel routes, gateway could be not on-link.
1088 *
1089 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1090 * results in pretty ugly and hairy code with obscure logic.
1091 *
1092 * I chose to generalized it instead, so that the size
1093 * of code does not increase practically, but it becomes
1094 * much more general.
1095 * Every prefix is assigned a "scope" value: "host" is local address,
1096 * "link" is direct route,
1097 * [ ... "site" ... "interior" ... ]
1098 * and "universe" is true gateway route with global meaning.
1099 *
1100 * Every prefix refers to a set of "nexthop"s (gw, oif),
1101 * where gw must have narrower scope. This recursion stops
1102 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1103 * which means that gw is forced to be on link.
1104 *
1105 * Code is still hairy, but now it is apparently logically
1106 * consistent and very flexible. F.e. as by-product it allows
1107 * to co-exists in peace independent exterior and interior
1108 * routing processes.
1109 *
1110 * Normally it looks as following.
1111 *
1112 * {universe prefix} -> (gw, oif) [scope link]
1113 * |
1114 * |-> {link prefix} -> (gw, oif) [scope local]
1115 * |
1116 * |-> {local prefix} (terminal node)
1117 */
fib_check_nh_v4_gw(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1118 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1119 u8 scope, struct netlink_ext_ack *extack)
1120 {
1121 struct net_device *dev;
1122 struct fib_result res;
1123 int err = 0;
1124
1125 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1126 unsigned int addr_type;
1127
1128 if (scope >= RT_SCOPE_LINK) {
1129 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1130 return -EINVAL;
1131 }
1132 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1133 if (!dev) {
1134 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1135 return -ENODEV;
1136 }
1137 if (!(dev->flags & IFF_UP)) {
1138 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1139 return -ENETDOWN;
1140 }
1141 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1142 if (addr_type != RTN_UNICAST) {
1143 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1144 return -EINVAL;
1145 }
1146 if (!netif_carrier_ok(dev))
1147 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1148 nh->fib_nh_dev = dev;
1149 dev_hold(dev);
1150 nh->fib_nh_scope = RT_SCOPE_LINK;
1151 return 0;
1152 }
1153 rcu_read_lock();
1154 {
1155 struct fib_table *tbl = NULL;
1156 struct flowi4 fl4 = {
1157 .daddr = nh->fib_nh_gw4,
1158 .flowi4_scope = scope + 1,
1159 .flowi4_oif = nh->fib_nh_oif,
1160 .flowi4_iif = LOOPBACK_IFINDEX,
1161 };
1162
1163 /* It is not necessary, but requires a bit of thinking */
1164 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1165 fl4.flowi4_scope = RT_SCOPE_LINK;
1166
1167 if (table && table != RT_TABLE_MAIN)
1168 tbl = fib_get_table(net, table);
1169
1170 if (tbl)
1171 err = fib_table_lookup(tbl, &fl4, &res,
1172 FIB_LOOKUP_IGNORE_LINKSTATE |
1173 FIB_LOOKUP_NOREF);
1174
1175 /* on error or if no table given do full lookup. This
1176 * is needed for example when nexthops are in the local
1177 * table rather than the given table
1178 */
1179 if (!tbl || err) {
1180 err = fib_lookup(net, &fl4, &res,
1181 FIB_LOOKUP_IGNORE_LINKSTATE);
1182 }
1183
1184 if (err) {
1185 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1186 goto out;
1187 }
1188 }
1189
1190 err = -EINVAL;
1191 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1192 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1193 goto out;
1194 }
1195 nh->fib_nh_scope = res.scope;
1196 nh->fib_nh_oif = FIB_RES_OIF(res);
1197 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1198 if (!dev) {
1199 NL_SET_ERR_MSG(extack,
1200 "No egress device for nexthop gateway");
1201 goto out;
1202 }
1203 dev_hold(dev);
1204 if (!netif_carrier_ok(dev))
1205 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1206 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1207 out:
1208 rcu_read_unlock();
1209 return err;
1210 }
1211
fib_check_nh_nongw(struct net * net,struct fib_nh * nh,struct netlink_ext_ack * extack)1212 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1213 struct netlink_ext_ack *extack)
1214 {
1215 struct in_device *in_dev;
1216 int err;
1217
1218 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1219 NL_SET_ERR_MSG(extack,
1220 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1221 return -EINVAL;
1222 }
1223
1224 rcu_read_lock();
1225
1226 err = -ENODEV;
1227 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1228 if (!in_dev)
1229 goto out;
1230 err = -ENETDOWN;
1231 if (!(in_dev->dev->flags & IFF_UP)) {
1232 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1233 goto out;
1234 }
1235
1236 nh->fib_nh_dev = in_dev->dev;
1237 dev_hold(nh->fib_nh_dev);
1238 nh->fib_nh_scope = RT_SCOPE_LINK;
1239 if (!netif_carrier_ok(nh->fib_nh_dev))
1240 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1241 err = 0;
1242 out:
1243 rcu_read_unlock();
1244 return err;
1245 }
1246
fib_check_nh(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1247 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1248 struct netlink_ext_ack *extack)
1249 {
1250 int err;
1251
1252 if (nh->fib_nh_gw_family == AF_INET)
1253 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1254 else if (nh->fib_nh_gw_family == AF_INET6)
1255 err = fib_check_nh_v6_gw(net, nh, table, extack);
1256 else
1257 err = fib_check_nh_nongw(net, nh, extack);
1258
1259 return err;
1260 }
1261
fib_laddr_hashfn(__be32 val)1262 static inline unsigned int fib_laddr_hashfn(__be32 val)
1263 {
1264 unsigned int mask = (fib_info_hash_size - 1);
1265
1266 return ((__force u32)val ^
1267 ((__force u32)val >> 7) ^
1268 ((__force u32)val >> 14)) & mask;
1269 }
1270
fib_info_hash_alloc(int bytes)1271 static struct hlist_head *fib_info_hash_alloc(int bytes)
1272 {
1273 if (bytes <= PAGE_SIZE)
1274 return kzalloc(bytes, GFP_KERNEL);
1275 else
1276 return (struct hlist_head *)
1277 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1278 get_order(bytes));
1279 }
1280
fib_info_hash_free(struct hlist_head * hash,int bytes)1281 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1282 {
1283 if (!hash)
1284 return;
1285
1286 if (bytes <= PAGE_SIZE)
1287 kfree(hash);
1288 else
1289 free_pages((unsigned long) hash, get_order(bytes));
1290 }
1291
fib_info_hash_move(struct hlist_head * new_info_hash,struct hlist_head * new_laddrhash,unsigned int new_size)1292 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1293 struct hlist_head *new_laddrhash,
1294 unsigned int new_size)
1295 {
1296 struct hlist_head *old_info_hash, *old_laddrhash;
1297 unsigned int old_size = fib_info_hash_size;
1298 unsigned int i, bytes;
1299
1300 spin_lock_bh(&fib_info_lock);
1301 old_info_hash = fib_info_hash;
1302 old_laddrhash = fib_info_laddrhash;
1303 fib_info_hash_size = new_size;
1304
1305 for (i = 0; i < old_size; i++) {
1306 struct hlist_head *head = &fib_info_hash[i];
1307 struct hlist_node *n;
1308 struct fib_info *fi;
1309
1310 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1311 struct hlist_head *dest;
1312 unsigned int new_hash;
1313
1314 new_hash = fib_info_hashfn(fi);
1315 dest = &new_info_hash[new_hash];
1316 hlist_add_head(&fi->fib_hash, dest);
1317 }
1318 }
1319 fib_info_hash = new_info_hash;
1320
1321 for (i = 0; i < old_size; i++) {
1322 struct hlist_head *lhead = &fib_info_laddrhash[i];
1323 struct hlist_node *n;
1324 struct fib_info *fi;
1325
1326 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1327 struct hlist_head *ldest;
1328 unsigned int new_hash;
1329
1330 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1331 ldest = &new_laddrhash[new_hash];
1332 hlist_add_head(&fi->fib_lhash, ldest);
1333 }
1334 }
1335 fib_info_laddrhash = new_laddrhash;
1336
1337 spin_unlock_bh(&fib_info_lock);
1338
1339 bytes = old_size * sizeof(struct hlist_head *);
1340 fib_info_hash_free(old_info_hash, bytes);
1341 fib_info_hash_free(old_laddrhash, bytes);
1342 }
1343
fib_info_update_nhc_saddr(struct net * net,struct fib_nh_common * nhc,unsigned char scope)1344 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1345 unsigned char scope)
1346 {
1347 struct fib_nh *nh;
1348 __be32 saddr;
1349
1350 if (nhc->nhc_family != AF_INET)
1351 return inet_select_addr(nhc->nhc_dev, 0, scope);
1352
1353 nh = container_of(nhc, struct fib_nh, nh_common);
1354 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1355
1356 WRITE_ONCE(nh->nh_saddr, saddr);
1357 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid));
1358
1359 return saddr;
1360 }
1361
fib_result_prefsrc(struct net * net,struct fib_result * res)1362 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1363 {
1364 struct fib_nh_common *nhc = res->nhc;
1365
1366 if (res->fi->fib_prefsrc)
1367 return res->fi->fib_prefsrc;
1368
1369 if (nhc->nhc_family == AF_INET) {
1370 struct fib_nh *nh;
1371
1372 nh = container_of(nhc, struct fib_nh, nh_common);
1373 if (READ_ONCE(nh->nh_saddr_genid) ==
1374 atomic_read(&net->ipv4.dev_addr_genid))
1375 return READ_ONCE(nh->nh_saddr);
1376 }
1377
1378 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1379 }
1380
fib_valid_prefsrc(struct fib_config * cfg,__be32 fib_prefsrc)1381 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1382 {
1383 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1384 fib_prefsrc != cfg->fc_dst) {
1385 u32 tb_id = cfg->fc_table;
1386 int rc;
1387
1388 if (tb_id == RT_TABLE_MAIN)
1389 tb_id = RT_TABLE_LOCAL;
1390
1391 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1392 fib_prefsrc, tb_id);
1393
1394 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1395 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1396 fib_prefsrc, RT_TABLE_LOCAL);
1397 }
1398
1399 if (rc != RTN_LOCAL)
1400 return false;
1401 }
1402 return true;
1403 }
1404
fib_create_info(struct fib_config * cfg,struct netlink_ext_ack * extack)1405 struct fib_info *fib_create_info(struct fib_config *cfg,
1406 struct netlink_ext_ack *extack)
1407 {
1408 int err;
1409 struct fib_info *fi = NULL;
1410 struct nexthop *nh = NULL;
1411 struct fib_info *ofi;
1412 int nhs = 1;
1413 struct net *net = cfg->fc_nlinfo.nl_net;
1414
1415 if (cfg->fc_type > RTN_MAX)
1416 goto err_inval;
1417
1418 /* Fast check to catch the most weird cases */
1419 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1420 NL_SET_ERR_MSG(extack, "Invalid scope");
1421 goto err_inval;
1422 }
1423
1424 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1425 NL_SET_ERR_MSG(extack,
1426 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1427 goto err_inval;
1428 }
1429
1430 if (cfg->fc_nh_id) {
1431 if (!cfg->fc_mx) {
1432 fi = fib_find_info_nh(net, cfg);
1433 if (fi) {
1434 fi->fib_treeref++;
1435 return fi;
1436 }
1437 }
1438
1439 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1440 if (!nh) {
1441 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1442 goto err_inval;
1443 }
1444 nhs = 0;
1445 }
1446
1447 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1448 if (cfg->fc_mp) {
1449 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1450 if (nhs == 0)
1451 goto err_inval;
1452 }
1453 #endif
1454
1455 err = -ENOBUFS;
1456
1457 /* Paired with WRITE_ONCE() in fib_release_info() */
1458 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) {
1459 unsigned int new_size = fib_info_hash_size << 1;
1460 struct hlist_head *new_info_hash;
1461 struct hlist_head *new_laddrhash;
1462 unsigned int bytes;
1463
1464 if (!new_size)
1465 new_size = 16;
1466 bytes = new_size * sizeof(struct hlist_head *);
1467 new_info_hash = fib_info_hash_alloc(bytes);
1468 new_laddrhash = fib_info_hash_alloc(bytes);
1469 if (!new_info_hash || !new_laddrhash) {
1470 fib_info_hash_free(new_info_hash, bytes);
1471 fib_info_hash_free(new_laddrhash, bytes);
1472 } else
1473 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1474
1475 if (!fib_info_hash_size)
1476 goto failure;
1477 }
1478
1479 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1480 if (!fi)
1481 goto failure;
1482 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1483 cfg->fc_mx_len, extack);
1484 if (IS_ERR(fi->fib_metrics)) {
1485 err = PTR_ERR(fi->fib_metrics);
1486 kfree(fi);
1487 return ERR_PTR(err);
1488 }
1489
1490 fi->fib_net = net;
1491 fi->fib_protocol = cfg->fc_protocol;
1492 fi->fib_scope = cfg->fc_scope;
1493 fi->fib_flags = cfg->fc_flags;
1494 fi->fib_priority = cfg->fc_priority;
1495 fi->fib_prefsrc = cfg->fc_prefsrc;
1496 fi->fib_type = cfg->fc_type;
1497 fi->fib_tb_id = cfg->fc_table;
1498
1499 fi->fib_nhs = nhs;
1500 if (nh) {
1501 if (!nexthop_get(nh)) {
1502 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1503 err = -EINVAL;
1504 } else {
1505 err = 0;
1506 fi->nh = nh;
1507 }
1508 } else {
1509 change_nexthops(fi) {
1510 nexthop_nh->nh_parent = fi;
1511 } endfor_nexthops(fi)
1512
1513 if (cfg->fc_mp)
1514 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1515 extack);
1516 else
1517 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1518 }
1519
1520 if (err != 0)
1521 goto failure;
1522
1523 if (fib_props[cfg->fc_type].error) {
1524 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1525 NL_SET_ERR_MSG(extack,
1526 "Gateway, device and multipath can not be specified for this route type");
1527 goto err_inval;
1528 }
1529 goto link_it;
1530 } else {
1531 switch (cfg->fc_type) {
1532 case RTN_UNICAST:
1533 case RTN_LOCAL:
1534 case RTN_BROADCAST:
1535 case RTN_ANYCAST:
1536 case RTN_MULTICAST:
1537 break;
1538 default:
1539 NL_SET_ERR_MSG(extack, "Invalid route type");
1540 goto err_inval;
1541 }
1542 }
1543
1544 if (cfg->fc_scope > RT_SCOPE_HOST) {
1545 NL_SET_ERR_MSG(extack, "Invalid scope");
1546 goto err_inval;
1547 }
1548
1549 if (fi->nh) {
1550 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1551 if (err)
1552 goto failure;
1553 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1554 struct fib_nh *nh = fi->fib_nh;
1555
1556 /* Local address is added. */
1557 if (nhs != 1) {
1558 NL_SET_ERR_MSG(extack,
1559 "Route with host scope can not have multiple nexthops");
1560 goto err_inval;
1561 }
1562 if (nh->fib_nh_gw_family) {
1563 NL_SET_ERR_MSG(extack,
1564 "Route with host scope can not have a gateway");
1565 goto err_inval;
1566 }
1567 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1568 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1569 err = -ENODEV;
1570 if (!nh->fib_nh_dev)
1571 goto failure;
1572 } else {
1573 int linkdown = 0;
1574
1575 change_nexthops(fi) {
1576 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1577 cfg->fc_table, cfg->fc_scope,
1578 extack);
1579 if (err != 0)
1580 goto failure;
1581 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1582 linkdown++;
1583 } endfor_nexthops(fi)
1584 if (linkdown == fi->fib_nhs)
1585 fi->fib_flags |= RTNH_F_LINKDOWN;
1586 }
1587
1588 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1589 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1590 goto err_inval;
1591 }
1592
1593 if (!fi->nh) {
1594 change_nexthops(fi) {
1595 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1596 fi->fib_scope);
1597 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1598 fi->fib_nh_is_v6 = true;
1599 } endfor_nexthops(fi)
1600
1601 fib_rebalance(fi);
1602 }
1603
1604 link_it:
1605 ofi = fib_find_info(fi);
1606 if (ofi) {
1607 /* fib_table_lookup() should not see @fi yet. */
1608 fi->fib_dead = 1;
1609 free_fib_info(fi);
1610 ofi->fib_treeref++;
1611 return ofi;
1612 }
1613
1614 fi->fib_treeref++;
1615 refcount_set(&fi->fib_clntref, 1);
1616 spin_lock_bh(&fib_info_lock);
1617 fib_info_cnt++;
1618 hlist_add_head(&fi->fib_hash,
1619 &fib_info_hash[fib_info_hashfn(fi)]);
1620 if (fi->fib_prefsrc) {
1621 struct hlist_head *head;
1622
1623 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1624 hlist_add_head(&fi->fib_lhash, head);
1625 }
1626 if (fi->nh) {
1627 list_add(&fi->nh_list, &nh->fi_list);
1628 } else {
1629 change_nexthops(fi) {
1630 struct hlist_head *head;
1631
1632 if (!nexthop_nh->fib_nh_dev)
1633 continue;
1634 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
1635 hlist_add_head(&nexthop_nh->nh_hash, head);
1636 } endfor_nexthops(fi)
1637 }
1638 spin_unlock_bh(&fib_info_lock);
1639 return fi;
1640
1641 err_inval:
1642 err = -EINVAL;
1643
1644 failure:
1645 if (fi) {
1646 /* fib_table_lookup() should not see @fi yet. */
1647 fi->fib_dead = 1;
1648 free_fib_info(fi);
1649 }
1650
1651 return ERR_PTR(err);
1652 }
1653
fib_nexthop_info(struct sk_buff * skb,const struct fib_nh_common * nhc,u8 rt_family,unsigned char * flags,bool skip_oif)1654 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1655 u8 rt_family, unsigned char *flags, bool skip_oif)
1656 {
1657 if (nhc->nhc_flags & RTNH_F_DEAD)
1658 *flags |= RTNH_F_DEAD;
1659
1660 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1661 *flags |= RTNH_F_LINKDOWN;
1662
1663 rcu_read_lock();
1664 switch (nhc->nhc_family) {
1665 case AF_INET:
1666 if (ip_ignore_linkdown(nhc->nhc_dev))
1667 *flags |= RTNH_F_DEAD;
1668 break;
1669 case AF_INET6:
1670 if (ip6_ignore_linkdown(nhc->nhc_dev))
1671 *flags |= RTNH_F_DEAD;
1672 break;
1673 }
1674 rcu_read_unlock();
1675 }
1676
1677 switch (nhc->nhc_gw_family) {
1678 case AF_INET:
1679 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1680 goto nla_put_failure;
1681 break;
1682 case AF_INET6:
1683 /* if gateway family does not match nexthop family
1684 * gateway is encoded as RTA_VIA
1685 */
1686 if (rt_family != nhc->nhc_gw_family) {
1687 int alen = sizeof(struct in6_addr);
1688 struct nlattr *nla;
1689 struct rtvia *via;
1690
1691 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1692 if (!nla)
1693 goto nla_put_failure;
1694
1695 via = nla_data(nla);
1696 via->rtvia_family = AF_INET6;
1697 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1698 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1699 &nhc->nhc_gw.ipv6) < 0) {
1700 goto nla_put_failure;
1701 }
1702 break;
1703 }
1704
1705 *flags |= (nhc->nhc_flags & RTNH_F_ONLINK);
1706 if (nhc->nhc_flags & RTNH_F_OFFLOAD)
1707 *flags |= RTNH_F_OFFLOAD;
1708
1709 if (!skip_oif && nhc->nhc_dev &&
1710 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1711 goto nla_put_failure;
1712
1713 if (nhc->nhc_lwtstate &&
1714 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1715 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1716 goto nla_put_failure;
1717
1718 return 0;
1719
1720 nla_put_failure:
1721 return -EMSGSIZE;
1722 }
1723 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1724
1725 #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)1726 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1727 int nh_weight, u8 rt_family, u32 nh_tclassid)
1728 {
1729 const struct net_device *dev = nhc->nhc_dev;
1730 struct rtnexthop *rtnh;
1731 unsigned char flags = 0;
1732
1733 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1734 if (!rtnh)
1735 goto nla_put_failure;
1736
1737 rtnh->rtnh_hops = nh_weight - 1;
1738 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1739
1740 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1741 goto nla_put_failure;
1742
1743 rtnh->rtnh_flags = flags;
1744
1745 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1746 goto nla_put_failure;
1747
1748 /* length of rtnetlink header + attributes */
1749 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1750
1751 return 0;
1752
1753 nla_put_failure:
1754 return -EMSGSIZE;
1755 }
1756 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1757 #endif
1758
1759 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1760 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1761 {
1762 struct nlattr *mp;
1763
1764 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1765 if (!mp)
1766 goto nla_put_failure;
1767
1768 if (unlikely(fi->nh)) {
1769 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1770 goto nla_put_failure;
1771 goto mp_end;
1772 }
1773
1774 for_nexthops(fi) {
1775 u32 nh_tclassid = 0;
1776 #ifdef CONFIG_IP_ROUTE_CLASSID
1777 nh_tclassid = nh->nh_tclassid;
1778 #endif
1779 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1780 AF_INET, nh_tclassid) < 0)
1781 goto nla_put_failure;
1782 } endfor_nexthops(fi);
1783
1784 mp_end:
1785 nla_nest_end(skb, mp);
1786
1787 return 0;
1788
1789 nla_put_failure:
1790 return -EMSGSIZE;
1791 }
1792 #else
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1793 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1794 {
1795 return 0;
1796 }
1797 #endif
1798
fib_dump_info(struct sk_buff * skb,u32 portid,u32 seq,int event,struct fib_rt_info * fri,unsigned int flags)1799 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1800 struct fib_rt_info *fri, unsigned int flags)
1801 {
1802 unsigned int nhs = fib_info_num_path(fri->fi);
1803 struct fib_info *fi = fri->fi;
1804 u32 tb_id = fri->tb_id;
1805 struct nlmsghdr *nlh;
1806 struct rtmsg *rtm;
1807
1808 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1809 if (!nlh)
1810 return -EMSGSIZE;
1811
1812 rtm = nlmsg_data(nlh);
1813 rtm->rtm_family = AF_INET;
1814 rtm->rtm_dst_len = fri->dst_len;
1815 rtm->rtm_src_len = 0;
1816 rtm->rtm_tos = fri->tos;
1817 if (tb_id < 256)
1818 rtm->rtm_table = tb_id;
1819 else
1820 rtm->rtm_table = RT_TABLE_COMPAT;
1821 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1822 goto nla_put_failure;
1823 rtm->rtm_type = fri->type;
1824 rtm->rtm_flags = fi->fib_flags;
1825 rtm->rtm_scope = fi->fib_scope;
1826 rtm->rtm_protocol = fi->fib_protocol;
1827
1828 if (rtm->rtm_dst_len &&
1829 nla_put_in_addr(skb, RTA_DST, fri->dst))
1830 goto nla_put_failure;
1831 if (fi->fib_priority &&
1832 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1833 goto nla_put_failure;
1834 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1835 goto nla_put_failure;
1836
1837 if (fi->fib_prefsrc &&
1838 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1839 goto nla_put_failure;
1840
1841 if (fi->nh) {
1842 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1843 goto nla_put_failure;
1844 if (nexthop_is_blackhole(fi->nh))
1845 rtm->rtm_type = RTN_BLACKHOLE;
1846 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
1847 goto offload;
1848 }
1849
1850 if (nhs == 1) {
1851 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1852 unsigned char flags = 0;
1853
1854 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1855 goto nla_put_failure;
1856
1857 rtm->rtm_flags = flags;
1858 #ifdef CONFIG_IP_ROUTE_CLASSID
1859 if (nhc->nhc_family == AF_INET) {
1860 struct fib_nh *nh;
1861
1862 nh = container_of(nhc, struct fib_nh, nh_common);
1863 if (nh->nh_tclassid &&
1864 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1865 goto nla_put_failure;
1866 }
1867 #endif
1868 } else {
1869 if (fib_add_multipath(skb, fi) < 0)
1870 goto nla_put_failure;
1871 }
1872
1873 offload:
1874 if (fri->offload)
1875 rtm->rtm_flags |= RTM_F_OFFLOAD;
1876 if (fri->trap)
1877 rtm->rtm_flags |= RTM_F_TRAP;
1878
1879 nlmsg_end(skb, nlh);
1880 return 0;
1881
1882 nla_put_failure:
1883 nlmsg_cancel(skb, nlh);
1884 return -EMSGSIZE;
1885 }
1886
1887 /*
1888 * Update FIB if:
1889 * - local address disappeared -> we must delete all the entries
1890 * referring to it.
1891 * - device went down -> we must shutdown all nexthops going via it.
1892 */
fib_sync_down_addr(struct net_device * dev,__be32 local)1893 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1894 {
1895 int ret = 0;
1896 unsigned int hash = fib_laddr_hashfn(local);
1897 struct hlist_head *head = &fib_info_laddrhash[hash];
1898 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1899 struct net *net = dev_net(dev);
1900 struct fib_info *fi;
1901
1902 if (!fib_info_laddrhash || local == 0)
1903 return 0;
1904
1905 hlist_for_each_entry(fi, head, fib_lhash) {
1906 if (!net_eq(fi->fib_net, net) ||
1907 fi->fib_tb_id != tb_id)
1908 continue;
1909 if (fi->fib_prefsrc == local) {
1910 fi->fib_flags |= RTNH_F_DEAD;
1911 ret++;
1912 }
1913 }
1914 return ret;
1915 }
1916
call_fib_nh_notifiers(struct fib_nh * nh,enum fib_event_type event_type)1917 static int call_fib_nh_notifiers(struct fib_nh *nh,
1918 enum fib_event_type event_type)
1919 {
1920 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1921 struct fib_nh_notifier_info info = {
1922 .fib_nh = nh,
1923 };
1924
1925 switch (event_type) {
1926 case FIB_EVENT_NH_ADD:
1927 if (nh->fib_nh_flags & RTNH_F_DEAD)
1928 break;
1929 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1930 break;
1931 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1932 &info.info);
1933 case FIB_EVENT_NH_DEL:
1934 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1935 (nh->fib_nh_flags & RTNH_F_DEAD))
1936 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1937 event_type, &info.info);
1938 default:
1939 break;
1940 }
1941
1942 return NOTIFY_DONE;
1943 }
1944
1945 /* Update the PMTU of exceptions when:
1946 * - the new MTU of the first hop becomes smaller than the PMTU
1947 * - the old MTU was the same as the PMTU, and it limited discovery of
1948 * larger MTUs on the path. With that limit raised, we can now
1949 * discover larger MTUs
1950 * A special case is locked exceptions, for which the PMTU is smaller
1951 * than the minimal accepted PMTU:
1952 * - if the new MTU is greater than the PMTU, don't make any change
1953 * - otherwise, unlock and set PMTU
1954 */
fib_nhc_update_mtu(struct fib_nh_common * nhc,u32 new,u32 orig)1955 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1956 {
1957 struct fnhe_hash_bucket *bucket;
1958 int i;
1959
1960 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1961 if (!bucket)
1962 return;
1963
1964 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1965 struct fib_nh_exception *fnhe;
1966
1967 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1968 fnhe;
1969 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1970 if (fnhe->fnhe_mtu_locked) {
1971 if (new <= fnhe->fnhe_pmtu) {
1972 fnhe->fnhe_pmtu = new;
1973 fnhe->fnhe_mtu_locked = false;
1974 }
1975 } else if (new < fnhe->fnhe_pmtu ||
1976 orig == fnhe->fnhe_pmtu) {
1977 fnhe->fnhe_pmtu = new;
1978 }
1979 }
1980 }
1981 }
1982
fib_sync_mtu(struct net_device * dev,u32 orig_mtu)1983 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1984 {
1985 struct hlist_head *head = fib_info_devhash_bucket(dev);
1986 struct fib_nh *nh;
1987
1988 hlist_for_each_entry(nh, head, nh_hash) {
1989 if (nh->fib_nh_dev == dev)
1990 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1991 }
1992 }
1993
1994 /* Event force Flags Description
1995 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1996 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1997 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1998 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1999 *
2000 * only used when fib_nh is built into fib_info
2001 */
fib_sync_down_dev(struct net_device * dev,unsigned long event,bool force)2002 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
2003 {
2004 struct hlist_head *head = fib_info_devhash_bucket(dev);
2005 struct fib_info *prev_fi = NULL;
2006 int scope = RT_SCOPE_NOWHERE;
2007 struct fib_nh *nh;
2008 int ret = 0;
2009
2010 if (force)
2011 scope = -1;
2012
2013 hlist_for_each_entry(nh, head, nh_hash) {
2014 struct fib_info *fi = nh->nh_parent;
2015 int dead;
2016
2017 BUG_ON(!fi->fib_nhs);
2018 if (nh->fib_nh_dev != dev || fi == prev_fi)
2019 continue;
2020 prev_fi = fi;
2021 dead = 0;
2022 change_nexthops(fi) {
2023 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
2024 dead++;
2025 else if (nexthop_nh->fib_nh_dev == dev &&
2026 nexthop_nh->fib_nh_scope != scope) {
2027 switch (event) {
2028 case NETDEV_DOWN:
2029 case NETDEV_UNREGISTER:
2030 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
2031 fallthrough;
2032 case NETDEV_CHANGE:
2033 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
2034 break;
2035 }
2036 call_fib_nh_notifiers(nexthop_nh,
2037 FIB_EVENT_NH_DEL);
2038 dead++;
2039 }
2040 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2041 if (event == NETDEV_UNREGISTER &&
2042 nexthop_nh->fib_nh_dev == dev) {
2043 dead = fi->fib_nhs;
2044 break;
2045 }
2046 #endif
2047 } endfor_nexthops(fi)
2048 if (dead == fi->fib_nhs) {
2049 switch (event) {
2050 case NETDEV_DOWN:
2051 case NETDEV_UNREGISTER:
2052 fi->fib_flags |= RTNH_F_DEAD;
2053 fallthrough;
2054 case NETDEV_CHANGE:
2055 fi->fib_flags |= RTNH_F_LINKDOWN;
2056 break;
2057 }
2058 ret++;
2059 }
2060
2061 fib_rebalance(fi);
2062 }
2063
2064 return ret;
2065 }
2066
2067 /* Must be invoked inside of an RCU protected region. */
fib_select_default(const struct flowi4 * flp,struct fib_result * res)2068 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2069 {
2070 struct fib_info *fi = NULL, *last_resort = NULL;
2071 struct hlist_head *fa_head = res->fa_head;
2072 struct fib_table *tb = res->table;
2073 u8 slen = 32 - res->prefixlen;
2074 int order = -1, last_idx = -1;
2075 struct fib_alias *fa, *fa1 = NULL;
2076 u32 last_prio = res->fi->fib_priority;
2077 u8 last_tos = 0;
2078
2079 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2080 struct fib_info *next_fi = fa->fa_info;
2081 struct fib_nh_common *nhc;
2082
2083 if (fa->fa_slen != slen)
2084 continue;
2085 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2086 continue;
2087 if (fa->tb_id != tb->tb_id)
2088 continue;
2089 if (next_fi->fib_priority > last_prio &&
2090 fa->fa_tos == last_tos) {
2091 if (last_tos)
2092 continue;
2093 break;
2094 }
2095 if (next_fi->fib_flags & RTNH_F_DEAD)
2096 continue;
2097 last_tos = fa->fa_tos;
2098 last_prio = next_fi->fib_priority;
2099
2100 if (next_fi->fib_scope != res->scope ||
2101 fa->fa_type != RTN_UNICAST)
2102 continue;
2103
2104 nhc = fib_info_nhc(next_fi, 0);
2105 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2106 continue;
2107
2108 fib_alias_accessed(fa);
2109
2110 if (!fi) {
2111 if (next_fi != res->fi)
2112 break;
2113 fa1 = fa;
2114 } else if (!fib_detect_death(fi, order, &last_resort,
2115 &last_idx, fa1->fa_default)) {
2116 fib_result_assign(res, fi);
2117 fa1->fa_default = order;
2118 goto out;
2119 }
2120 fi = next_fi;
2121 order++;
2122 }
2123
2124 if (order <= 0 || !fi) {
2125 if (fa1)
2126 fa1->fa_default = -1;
2127 goto out;
2128 }
2129
2130 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2131 fa1->fa_default)) {
2132 fib_result_assign(res, fi);
2133 fa1->fa_default = order;
2134 goto out;
2135 }
2136
2137 if (last_idx >= 0)
2138 fib_result_assign(res, last_resort);
2139 fa1->fa_default = last_idx;
2140 out:
2141 return;
2142 }
2143
2144 /*
2145 * Dead device goes up. We wake up dead nexthops.
2146 * It takes sense only on multipath routes.
2147 *
2148 * only used when fib_nh is built into fib_info
2149 */
fib_sync_up(struct net_device * dev,unsigned char nh_flags)2150 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2151 {
2152 struct fib_info *prev_fi;
2153 struct hlist_head *head;
2154 struct fib_nh *nh;
2155 int ret;
2156
2157 if (!(dev->flags & IFF_UP))
2158 return 0;
2159
2160 if (nh_flags & RTNH_F_DEAD) {
2161 unsigned int flags = dev_get_flags(dev);
2162
2163 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2164 nh_flags |= RTNH_F_LINKDOWN;
2165 }
2166
2167 prev_fi = NULL;
2168 head = fib_info_devhash_bucket(dev);
2169 ret = 0;
2170
2171 hlist_for_each_entry(nh, head, nh_hash) {
2172 struct fib_info *fi = nh->nh_parent;
2173 int alive;
2174
2175 BUG_ON(!fi->fib_nhs);
2176 if (nh->fib_nh_dev != dev || fi == prev_fi)
2177 continue;
2178
2179 prev_fi = fi;
2180 alive = 0;
2181 change_nexthops(fi) {
2182 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2183 alive++;
2184 continue;
2185 }
2186 if (!nexthop_nh->fib_nh_dev ||
2187 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2188 continue;
2189 if (nexthop_nh->fib_nh_dev != dev ||
2190 !__in_dev_get_rtnl(dev))
2191 continue;
2192 alive++;
2193 nexthop_nh->fib_nh_flags &= ~nh_flags;
2194 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2195 } endfor_nexthops(fi)
2196
2197 if (alive > 0) {
2198 fi->fib_flags &= ~nh_flags;
2199 ret++;
2200 }
2201
2202 fib_rebalance(fi);
2203 }
2204
2205 return ret;
2206 }
2207
2208 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_good_nh(const struct fib_nh * nh)2209 static bool fib_good_nh(const struct fib_nh *nh)
2210 {
2211 int state = NUD_REACHABLE;
2212
2213 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2214 struct neighbour *n;
2215
2216 rcu_read_lock_bh();
2217
2218 if (likely(nh->fib_nh_gw_family == AF_INET))
2219 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2220 (__force u32)nh->fib_nh_gw4);
2221 else if (nh->fib_nh_gw_family == AF_INET6)
2222 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2223 &nh->fib_nh_gw6);
2224 else
2225 n = NULL;
2226 if (n)
2227 state = n->nud_state;
2228
2229 rcu_read_unlock_bh();
2230 }
2231
2232 return !!(state & NUD_VALID);
2233 }
2234
fib_select_multipath(struct fib_result * res,int hash)2235 void fib_select_multipath(struct fib_result *res, int hash)
2236 {
2237 struct fib_info *fi = res->fi;
2238 struct net *net = fi->fib_net;
2239 bool first = false;
2240
2241 if (unlikely(res->fi->nh)) {
2242 nexthop_path_fib_result(res, hash);
2243 return;
2244 }
2245
2246 change_nexthops(fi) {
2247 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) {
2248 if (!fib_good_nh(nexthop_nh))
2249 continue;
2250 if (!first) {
2251 res->nh_sel = nhsel;
2252 res->nhc = &nexthop_nh->nh_common;
2253 first = true;
2254 }
2255 }
2256
2257 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2258 continue;
2259
2260 res->nh_sel = nhsel;
2261 res->nhc = &nexthop_nh->nh_common;
2262 return;
2263 } endfor_nexthops(fi);
2264 }
2265 #endif
2266
fib_select_path(struct net * net,struct fib_result * res,struct flowi4 * fl4,const struct sk_buff * skb)2267 void fib_select_path(struct net *net, struct fib_result *res,
2268 struct flowi4 *fl4, const struct sk_buff *skb)
2269 {
2270 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2271 goto check_saddr;
2272
2273 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2274 if (fib_info_num_path(res->fi) > 1) {
2275 int h = fib_multipath_hash(net, fl4, skb, NULL);
2276
2277 fib_select_multipath(res, h);
2278 }
2279 else
2280 #endif
2281 if (!res->prefixlen &&
2282 res->table->tb_num_default > 1 &&
2283 res->type == RTN_UNICAST)
2284 fib_select_default(fl4, res);
2285
2286 check_saddr:
2287 if (!fl4->saddr)
2288 fl4->saddr = fib_result_prefsrc(net, res);
2289 }
2290