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