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/inet_dscp.h>
37 #include <net/ip.h>
38 #include <net/protocol.h>
39 #include <net/route.h>
40 #include <net/tcp.h>
41 #include <net/sock.h>
42 #include <net/ip_fib.h>
43 #include <net/ip6_fib.h>
44 #include <net/nexthop.h>
45 #include <net/netlink.h>
46 #include <net/rtnh.h>
47 #include <net/lwtunnel.h>
48 #include <net/fib_notifier.h>
49 #include <net/addrconf.h>
50
51 #include "fib_lookup.h"
52
53 /* for_nexthops and change_nexthops only used when nexthop object
54 * is not set in a fib_info. The logic within can reference fib_nh.
55 */
56 #ifdef CONFIG_IP_ROUTE_MULTIPATH
57
58 #define for_nexthops(fi) { \
59 int nhsel; const struct fib_nh *nh; \
60 for (nhsel = 0, nh = (fi)->fib_nh; \
61 nhsel < fib_info_num_path((fi)); \
62 nh++, nhsel++)
63
64 #define change_nexthops(fi) { \
65 int nhsel; struct fib_nh *nexthop_nh; \
66 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
67 nhsel < fib_info_num_path((fi)); \
68 nexthop_nh++, nhsel++)
69
70 #else /* CONFIG_IP_ROUTE_MULTIPATH */
71
72 /* Hope, that gcc will optimize it to get rid of dummy loop */
73
74 #define for_nexthops(fi) { \
75 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
76 for (nhsel = 0; nhsel < 1; nhsel++)
77
78 #define change_nexthops(fi) { \
79 int nhsel; \
80 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
81 for (nhsel = 0; nhsel < 1; nhsel++)
82
83 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
84
85 #define endfor_nexthops(fi) }
86
87
88 const struct fib_prop fib_props[RTN_MAX + 1] = {
89 [RTN_UNSPEC] = {
90 .error = 0,
91 .scope = RT_SCOPE_NOWHERE,
92 },
93 [RTN_UNICAST] = {
94 .error = 0,
95 .scope = RT_SCOPE_UNIVERSE,
96 },
97 [RTN_LOCAL] = {
98 .error = 0,
99 .scope = RT_SCOPE_HOST,
100 },
101 [RTN_BROADCAST] = {
102 .error = 0,
103 .scope = RT_SCOPE_LINK,
104 },
105 [RTN_ANYCAST] = {
106 .error = 0,
107 .scope = RT_SCOPE_LINK,
108 },
109 [RTN_MULTICAST] = {
110 .error = 0,
111 .scope = RT_SCOPE_UNIVERSE,
112 },
113 [RTN_BLACKHOLE] = {
114 .error = -EINVAL,
115 .scope = RT_SCOPE_UNIVERSE,
116 },
117 [RTN_UNREACHABLE] = {
118 .error = -EHOSTUNREACH,
119 .scope = RT_SCOPE_UNIVERSE,
120 },
121 [RTN_PROHIBIT] = {
122 .error = -EACCES,
123 .scope = RT_SCOPE_UNIVERSE,
124 },
125 [RTN_THROW] = {
126 .error = -EAGAIN,
127 .scope = RT_SCOPE_UNIVERSE,
128 },
129 [RTN_NAT] = {
130 .error = -EINVAL,
131 .scope = RT_SCOPE_NOWHERE,
132 },
133 [RTN_XRESOLVE] = {
134 .error = -EINVAL,
135 .scope = RT_SCOPE_NOWHERE,
136 },
137 };
138
rt_fibinfo_free(struct rtable __rcu ** rtp)139 static void rt_fibinfo_free(struct rtable __rcu **rtp)
140 {
141 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
142
143 if (!rt)
144 return;
145
146 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
147 * because we waited an RCU grace period before calling
148 * free_fib_info_rcu()
149 */
150
151 dst_dev_put(&rt->dst);
152 dst_release_immediate(&rt->dst);
153 }
154
free_nh_exceptions(struct fib_nh_common * nhc)155 static void free_nh_exceptions(struct fib_nh_common *nhc)
156 {
157 struct fnhe_hash_bucket *hash;
158 int i;
159
160 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
161 if (!hash)
162 return;
163 for (i = 0; i < FNHE_HASH_SIZE; i++) {
164 struct fib_nh_exception *fnhe;
165
166 fnhe = rcu_dereference_protected(hash[i].chain, 1);
167 while (fnhe) {
168 struct fib_nh_exception *next;
169
170 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
171
172 rt_fibinfo_free(&fnhe->fnhe_rth_input);
173 rt_fibinfo_free(&fnhe->fnhe_rth_output);
174
175 kfree(fnhe);
176
177 fnhe = next;
178 }
179 }
180 kfree(hash);
181 }
182
rt_fibinfo_free_cpus(struct rtable __rcu * __percpu * rtp)183 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
184 {
185 int cpu;
186
187 if (!rtp)
188 return;
189
190 for_each_possible_cpu(cpu) {
191 struct rtable *rt;
192
193 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
194 if (rt) {
195 dst_dev_put(&rt->dst);
196 dst_release_immediate(&rt->dst);
197 }
198 }
199 free_percpu(rtp);
200 }
201
fib_nh_common_release(struct fib_nh_common * nhc)202 void fib_nh_common_release(struct fib_nh_common *nhc)
203 {
204 netdev_put(nhc->nhc_dev, &nhc->nhc_dev_tracker);
205 lwtstate_put(nhc->nhc_lwtstate);
206 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
207 rt_fibinfo_free(&nhc->nhc_rth_input);
208 free_nh_exceptions(nhc);
209 }
210 EXPORT_SYMBOL_GPL(fib_nh_common_release);
211
fib_nh_release(struct net * net,struct fib_nh * fib_nh)212 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
213 {
214 #ifdef CONFIG_IP_ROUTE_CLASSID
215 if (fib_nh->nh_tclassid)
216 atomic_dec(&net->ipv4.fib_num_tclassid_users);
217 #endif
218 fib_nh_common_release(&fib_nh->nh_common);
219 }
220
221 /* Release a nexthop info record */
free_fib_info_rcu(struct rcu_head * head)222 static void free_fib_info_rcu(struct rcu_head *head)
223 {
224 struct fib_info *fi = container_of(head, struct fib_info, rcu);
225
226 if (fi->nh) {
227 nexthop_put(fi->nh);
228 } else {
229 change_nexthops(fi) {
230 fib_nh_release(fi->fib_net, nexthop_nh);
231 } endfor_nexthops(fi);
232 }
233
234 ip_fib_metrics_put(fi->fib_metrics);
235
236 kfree(fi);
237 }
238
free_fib_info(struct fib_info * fi)239 void free_fib_info(struct fib_info *fi)
240 {
241 if (fi->fib_dead == 0) {
242 pr_warn("Freeing alive fib_info %p\n", fi);
243 return;
244 }
245
246 call_rcu_hurry(&fi->rcu, free_fib_info_rcu);
247 }
248 EXPORT_SYMBOL_GPL(free_fib_info);
249
fib_release_info(struct fib_info * fi)250 void fib_release_info(struct fib_info *fi)
251 {
252 ASSERT_RTNL();
253 if (fi && refcount_dec_and_test(&fi->fib_treeref)) {
254 hlist_del(&fi->fib_hash);
255 fi->fib_net->ipv4.fib_info_cnt--;
256
257 if (fi->fib_prefsrc)
258 hlist_del(&fi->fib_lhash);
259 if (fi->nh) {
260 list_del(&fi->nh_list);
261 } else {
262 change_nexthops(fi) {
263 if (!nexthop_nh->fib_nh_dev)
264 continue;
265 hlist_del_rcu(&nexthop_nh->nh_hash);
266 } endfor_nexthops(fi)
267 }
268 /* Paired with READ_ONCE() from fib_table_lookup() */
269 WRITE_ONCE(fi->fib_dead, 1);
270 fib_info_put(fi);
271 }
272 }
273
nh_comp(struct fib_info * fi,struct fib_info * ofi)274 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
275 {
276 const struct fib_nh *onh;
277
278 if (fi->nh || ofi->nh)
279 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
280
281 if (ofi->fib_nhs == 0)
282 return 0;
283
284 for_nexthops(fi) {
285 onh = fib_info_nh(ofi, nhsel);
286
287 if (nh->fib_nh_oif != onh->fib_nh_oif ||
288 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
289 nh->fib_nh_scope != onh->fib_nh_scope ||
290 #ifdef CONFIG_IP_ROUTE_MULTIPATH
291 nh->fib_nh_weight != onh->fib_nh_weight ||
292 #endif
293 #ifdef CONFIG_IP_ROUTE_CLASSID
294 nh->nh_tclassid != onh->nh_tclassid ||
295 #endif
296 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
297 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
298 return -1;
299
300 if (nh->fib_nh_gw_family == AF_INET &&
301 nh->fib_nh_gw4 != onh->fib_nh_gw4)
302 return -1;
303
304 if (nh->fib_nh_gw_family == AF_INET6 &&
305 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
306 return -1;
307 } endfor_nexthops(fi);
308 return 0;
309 }
310
fib_nh_head(struct net_device * dev)311 static struct hlist_head *fib_nh_head(struct net_device *dev)
312 {
313 return &dev->fib_nh_head;
314 }
315
fib_info_hashfn_1(int init_val,u8 protocol,u8 scope,u32 prefsrc,u32 priority)316 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
317 u32 prefsrc, u32 priority)
318 {
319 unsigned int val = init_val;
320
321 val ^= (protocol << 8) | scope;
322 val ^= prefsrc;
323 val ^= priority;
324
325 return val;
326 }
327
fib_info_hashfn_result(const struct net * net,unsigned int val)328 static unsigned int fib_info_hashfn_result(const struct net *net,
329 unsigned int val)
330 {
331 return hash_32(val ^ net_hash_mix(net), net->ipv4.fib_info_hash_bits);
332 }
333
fib_info_hash_bucket(struct fib_info * fi)334 static struct hlist_head *fib_info_hash_bucket(struct fib_info *fi)
335 {
336 struct net *net = fi->fib_net;
337 unsigned int val;
338
339 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
340 fi->fib_scope, (__force u32)fi->fib_prefsrc,
341 fi->fib_priority);
342
343 if (fi->nh) {
344 val ^= fi->nh->id;
345 } else {
346 for_nexthops(fi) {
347 val ^= nh->fib_nh_oif;
348 } endfor_nexthops(fi)
349 }
350
351 return &net->ipv4.fib_info_hash[fib_info_hashfn_result(net, val)];
352 }
353
fib_info_laddrhash_bucket(const struct net * net,__be32 val)354 static struct hlist_head *fib_info_laddrhash_bucket(const struct net *net,
355 __be32 val)
356 {
357 unsigned int hash_bits = net->ipv4.fib_info_hash_bits;
358 u32 slot;
359
360 slot = hash_32(net_hash_mix(net) ^ (__force u32)val, hash_bits);
361
362 return &net->ipv4.fib_info_hash[(1 << hash_bits) + slot];
363 }
364
fib_info_hash_alloc(unsigned int hash_bits)365 static struct hlist_head *fib_info_hash_alloc(unsigned int hash_bits)
366 {
367 /* The second half is used for prefsrc */
368 return kvcalloc((1 << hash_bits) * 2, sizeof(struct hlist_head),
369 GFP_KERNEL);
370 }
371
fib_info_hash_free(struct hlist_head * head)372 static void fib_info_hash_free(struct hlist_head *head)
373 {
374 kvfree(head);
375 }
376
fib_info_hash_grow(struct net * net)377 static void fib_info_hash_grow(struct net *net)
378 {
379 unsigned int old_size = 1 << net->ipv4.fib_info_hash_bits;
380 struct hlist_head *new_info_hash, *old_info_hash;
381 unsigned int i;
382
383 if (net->ipv4.fib_info_cnt < old_size)
384 return;
385
386 new_info_hash = fib_info_hash_alloc(net->ipv4.fib_info_hash_bits + 1);
387 if (!new_info_hash)
388 return;
389
390 old_info_hash = net->ipv4.fib_info_hash;
391 net->ipv4.fib_info_hash = new_info_hash;
392 net->ipv4.fib_info_hash_bits += 1;
393
394 for (i = 0; i < old_size; i++) {
395 struct hlist_head *head = &old_info_hash[i];
396 struct hlist_node *n;
397 struct fib_info *fi;
398
399 hlist_for_each_entry_safe(fi, n, head, fib_hash)
400 hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi));
401 }
402
403 for (i = 0; i < old_size; i++) {
404 struct hlist_head *lhead = &old_info_hash[old_size + i];
405 struct hlist_node *n;
406 struct fib_info *fi;
407
408 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash)
409 hlist_add_head(&fi->fib_lhash,
410 fib_info_laddrhash_bucket(fi->fib_net,
411 fi->fib_prefsrc));
412 }
413
414 fib_info_hash_free(old_info_hash);
415 }
416
417 /* no metrics, only nexthop id */
fib_find_info_nh(struct net * net,const struct fib_config * cfg)418 static struct fib_info *fib_find_info_nh(struct net *net,
419 const struct fib_config *cfg)
420 {
421 struct hlist_head *head;
422 struct fib_info *fi;
423 unsigned int hash;
424
425 hash = fib_info_hashfn_1(cfg->fc_nh_id,
426 cfg->fc_protocol, cfg->fc_scope,
427 (__force u32)cfg->fc_prefsrc,
428 cfg->fc_priority);
429 hash = fib_info_hashfn_result(net, hash);
430 head = &net->ipv4.fib_info_hash[hash];
431
432 hlist_for_each_entry(fi, head, fib_hash) {
433 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
434 continue;
435
436 if (cfg->fc_protocol == fi->fib_protocol &&
437 cfg->fc_scope == fi->fib_scope &&
438 cfg->fc_prefsrc == fi->fib_prefsrc &&
439 cfg->fc_priority == fi->fib_priority &&
440 cfg->fc_type == fi->fib_type &&
441 cfg->fc_table == fi->fib_tb_id &&
442 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
443 return fi;
444 }
445
446 return NULL;
447 }
448
fib_find_info(struct fib_info * nfi)449 static struct fib_info *fib_find_info(struct fib_info *nfi)
450 {
451 struct hlist_head *head = fib_info_hash_bucket(nfi);
452 struct fib_info *fi;
453
454 hlist_for_each_entry(fi, head, fib_hash) {
455 if (fi->fib_nhs != nfi->fib_nhs)
456 continue;
457
458 if (nfi->fib_protocol == fi->fib_protocol &&
459 nfi->fib_scope == fi->fib_scope &&
460 nfi->fib_prefsrc == fi->fib_prefsrc &&
461 nfi->fib_priority == fi->fib_priority &&
462 nfi->fib_type == fi->fib_type &&
463 nfi->fib_tb_id == fi->fib_tb_id &&
464 memcmp(nfi->fib_metrics, fi->fib_metrics,
465 sizeof(u32) * RTAX_MAX) == 0 &&
466 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
467 nh_comp(fi, nfi) == 0)
468 return fi;
469 }
470
471 return NULL;
472 }
473
474 /* Check, that the gateway is already configured.
475 * Used only by redirect accept routine, under rcu_read_lock();
476 */
ip_fib_check_default(__be32 gw,struct net_device * dev)477 int ip_fib_check_default(__be32 gw, struct net_device *dev)
478 {
479 struct hlist_head *head;
480 struct fib_nh *nh;
481
482 head = fib_nh_head(dev);
483
484 hlist_for_each_entry_rcu(nh, head, nh_hash) {
485 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
486 if (nh->fib_nh_gw4 == gw &&
487 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
488 return 0;
489 }
490 }
491
492 return -1;
493 }
494
fib_nlmsg_size(struct fib_info * fi)495 size_t fib_nlmsg_size(struct fib_info *fi)
496 {
497 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
498 + nla_total_size(4) /* RTA_TABLE */
499 + nla_total_size(4) /* RTA_DST */
500 + nla_total_size(4) /* RTA_PRIORITY */
501 + nla_total_size(4) /* RTA_PREFSRC */
502 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
503 unsigned int nhs = fib_info_num_path(fi);
504
505 /* space for nested metrics */
506 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
507
508 if (fi->nh)
509 payload += nla_total_size(4); /* RTA_NH_ID */
510
511 if (nhs) {
512 size_t nh_encapsize = 0;
513 /* Also handles the special case nhs == 1 */
514
515 /* each nexthop is packed in an attribute */
516 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
517 unsigned int i;
518
519 /* may contain flow and gateway attribute */
520 nhsize += 2 * nla_total_size(4);
521
522 /* grab encap info */
523 for (i = 0; i < fib_info_num_path(fi); i++) {
524 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
525
526 if (nhc->nhc_lwtstate) {
527 /* RTA_ENCAP_TYPE */
528 nh_encapsize += lwtunnel_get_encap_size(
529 nhc->nhc_lwtstate);
530 /* RTA_ENCAP */
531 nh_encapsize += nla_total_size(2);
532 }
533 }
534
535 /* all nexthops are packed in a nested attribute */
536 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
537
538 }
539
540 return payload;
541 }
542
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)543 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
544 int dst_len, u32 tb_id, const struct nl_info *info,
545 unsigned int nlm_flags)
546 {
547 struct fib_rt_info fri;
548 struct sk_buff *skb;
549 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
550 int err = -ENOBUFS;
551
552 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
553 if (!skb)
554 goto errout;
555
556 fri.fi = fa->fa_info;
557 fri.tb_id = tb_id;
558 fri.dst = key;
559 fri.dst_len = dst_len;
560 fri.dscp = fa->fa_dscp;
561 fri.type = fa->fa_type;
562 fri.offload = READ_ONCE(fa->offload);
563 fri.trap = READ_ONCE(fa->trap);
564 fri.offload_failed = READ_ONCE(fa->offload_failed);
565 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
566 if (err < 0) {
567 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
568 WARN_ON(err == -EMSGSIZE);
569 kfree_skb(skb);
570 goto errout;
571 }
572 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
573 info->nlh, GFP_KERNEL);
574 return;
575 errout:
576 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
577 }
578
fib_detect_death(struct fib_info * fi,int order,struct fib_info ** last_resort,int * last_idx,int dflt)579 static int fib_detect_death(struct fib_info *fi, int order,
580 struct fib_info **last_resort, int *last_idx,
581 int dflt)
582 {
583 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
584 struct neighbour *n;
585 int state = NUD_NONE;
586
587 if (likely(nhc->nhc_gw_family == AF_INET))
588 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
589 else if (nhc->nhc_gw_family == AF_INET6)
590 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
591 nhc->nhc_dev);
592 else
593 n = NULL;
594
595 if (n) {
596 state = READ_ONCE(n->nud_state);
597 neigh_release(n);
598 } else {
599 return 0;
600 }
601 if (state == NUD_REACHABLE)
602 return 0;
603 if ((state & NUD_VALID) && order != dflt)
604 return 0;
605 if ((state & NUD_VALID) ||
606 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
607 *last_resort = fi;
608 *last_idx = order;
609 }
610 return 1;
611 }
612
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)613 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
614 struct nlattr *encap, u16 encap_type,
615 void *cfg, gfp_t gfp_flags,
616 struct netlink_ext_ack *extack)
617 {
618 int err;
619
620 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
621 gfp_flags);
622 if (!nhc->nhc_pcpu_rth_output)
623 return -ENOMEM;
624
625 if (encap) {
626 struct lwtunnel_state *lwtstate;
627
628 err = lwtunnel_build_state(net, encap_type, encap,
629 nhc->nhc_family, cfg, &lwtstate,
630 extack);
631 if (err)
632 goto lwt_failure;
633
634 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
635 }
636
637 return 0;
638
639 lwt_failure:
640 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
641 nhc->nhc_pcpu_rth_output = NULL;
642 return err;
643 }
644 EXPORT_SYMBOL_GPL(fib_nh_common_init);
645
fib_nh_init(struct net * net,struct fib_nh * nh,struct fib_config * cfg,int nh_weight,struct netlink_ext_ack * extack)646 int fib_nh_init(struct net *net, struct fib_nh *nh,
647 struct fib_config *cfg, int nh_weight,
648 struct netlink_ext_ack *extack)
649 {
650 int err;
651
652 nh->fib_nh_family = AF_INET;
653
654 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
655 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
656 if (err)
657 return err;
658
659 nh->fib_nh_oif = cfg->fc_oif;
660 nh->fib_nh_gw_family = cfg->fc_gw_family;
661 if (cfg->fc_gw_family == AF_INET)
662 nh->fib_nh_gw4 = cfg->fc_gw4;
663 else if (cfg->fc_gw_family == AF_INET6)
664 nh->fib_nh_gw6 = cfg->fc_gw6;
665
666 nh->fib_nh_flags = cfg->fc_flags;
667
668 #ifdef CONFIG_IP_ROUTE_CLASSID
669 nh->nh_tclassid = cfg->fc_flow;
670 if (nh->nh_tclassid)
671 atomic_inc(&net->ipv4.fib_num_tclassid_users);
672 #endif
673 #ifdef CONFIG_IP_ROUTE_MULTIPATH
674 nh->fib_nh_weight = nh_weight;
675 #endif
676 return 0;
677 }
678
679 #ifdef CONFIG_IP_ROUTE_MULTIPATH
680
fib_count_nexthops(struct rtnexthop * rtnh,int remaining,struct netlink_ext_ack * extack)681 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
682 struct netlink_ext_ack *extack)
683 {
684 int nhs = 0;
685
686 while (rtnh_ok(rtnh, remaining)) {
687 nhs++;
688 rtnh = rtnh_next(rtnh, &remaining);
689 }
690
691 /* leftover implies invalid nexthop configuration, discard it */
692 if (remaining > 0) {
693 NL_SET_ERR_MSG(extack,
694 "Invalid nexthop configuration - extra data after nexthops");
695 nhs = 0;
696 }
697
698 return nhs;
699 }
700
fib_gw_from_attr(__be32 * gw,struct nlattr * nla,struct netlink_ext_ack * extack)701 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
702 struct netlink_ext_ack *extack)
703 {
704 if (nla_len(nla) < sizeof(*gw)) {
705 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
706 return -EINVAL;
707 }
708
709 *gw = nla_get_in_addr(nla);
710
711 return 0;
712 }
713
714 /* 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)715 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
716 int remaining, struct fib_config *cfg,
717 struct netlink_ext_ack *extack)
718 {
719 struct net *net = fi->fib_net;
720 struct fib_config fib_cfg;
721 struct fib_nh *nh;
722 int ret;
723
724 change_nexthops(fi) {
725 int attrlen;
726
727 memset(&fib_cfg, 0, sizeof(fib_cfg));
728
729 if (!rtnh_ok(rtnh, remaining)) {
730 NL_SET_ERR_MSG(extack,
731 "Invalid nexthop configuration - extra data after nexthop");
732 return -EINVAL;
733 }
734
735 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
736 NL_SET_ERR_MSG(extack,
737 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
738 return -EINVAL;
739 }
740
741 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
742 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
743
744 attrlen = rtnh_attrlen(rtnh);
745 if (attrlen > 0) {
746 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
747
748 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
749 nlav = nla_find(attrs, attrlen, RTA_VIA);
750 if (nla && nlav) {
751 NL_SET_ERR_MSG(extack,
752 "Nexthop configuration can not contain both GATEWAY and VIA");
753 return -EINVAL;
754 }
755 if (nla) {
756 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
757 extack);
758 if (ret)
759 goto errout;
760
761 if (fib_cfg.fc_gw4)
762 fib_cfg.fc_gw_family = AF_INET;
763 } else if (nlav) {
764 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
765 if (ret)
766 goto errout;
767 }
768
769 nla = nla_find(attrs, attrlen, RTA_FLOW);
770 if (nla) {
771 if (nla_len(nla) < sizeof(u32)) {
772 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
773 return -EINVAL;
774 }
775 fib_cfg.fc_flow = nla_get_u32(nla);
776 }
777
778 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
779 /* RTA_ENCAP_TYPE length checked in
780 * lwtunnel_valid_encap_type_attr
781 */
782 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
783 if (nla)
784 fib_cfg.fc_encap_type = nla_get_u16(nla);
785 }
786
787 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
788 rtnh->rtnh_hops + 1, extack);
789 if (ret)
790 goto errout;
791
792 rtnh = rtnh_next(rtnh, &remaining);
793 } endfor_nexthops(fi);
794
795 ret = -EINVAL;
796 nh = fib_info_nh(fi, 0);
797 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
798 NL_SET_ERR_MSG(extack,
799 "Nexthop device index does not match RTA_OIF");
800 goto errout;
801 }
802 if (cfg->fc_gw_family) {
803 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
804 (cfg->fc_gw_family == AF_INET &&
805 nh->fib_nh_gw4 != cfg->fc_gw4) ||
806 (cfg->fc_gw_family == AF_INET6 &&
807 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
808 NL_SET_ERR_MSG(extack,
809 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
810 goto errout;
811 }
812 }
813 #ifdef CONFIG_IP_ROUTE_CLASSID
814 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
815 NL_SET_ERR_MSG(extack,
816 "Nexthop class id does not match RTA_FLOW");
817 goto errout;
818 }
819 #endif
820 ret = 0;
821 errout:
822 return ret;
823 }
824
825 /* only called when fib_nh is integrated into fib_info */
fib_rebalance(struct fib_info * fi)826 static void fib_rebalance(struct fib_info *fi)
827 {
828 int total;
829 int w;
830
831 if (fib_info_num_path(fi) < 2)
832 return;
833
834 total = 0;
835 for_nexthops(fi) {
836 if (nh->fib_nh_flags & RTNH_F_DEAD)
837 continue;
838
839 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
840 nh->fib_nh_flags & RTNH_F_LINKDOWN)
841 continue;
842
843 total += nh->fib_nh_weight;
844 } endfor_nexthops(fi);
845
846 w = 0;
847 change_nexthops(fi) {
848 int upper_bound;
849
850 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
851 upper_bound = -1;
852 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
853 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
854 upper_bound = -1;
855 } else {
856 w += nexthop_nh->fib_nh_weight;
857 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
858 total) - 1;
859 }
860
861 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
862 } endfor_nexthops(fi);
863 }
864 #else /* CONFIG_IP_ROUTE_MULTIPATH */
865
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)866 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
867 int remaining, struct fib_config *cfg,
868 struct netlink_ext_ack *extack)
869 {
870 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
871
872 return -EINVAL;
873 }
874
875 #define fib_rebalance(fi) do { } while (0)
876
877 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
878
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)879 static int fib_encap_match(struct net *net, u16 encap_type,
880 struct nlattr *encap,
881 const struct fib_nh *nh,
882 const struct fib_config *cfg,
883 struct netlink_ext_ack *extack)
884 {
885 struct lwtunnel_state *lwtstate;
886 int ret, result = 0;
887
888 if (encap_type == LWTUNNEL_ENCAP_NONE)
889 return 0;
890
891 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
892 cfg, &lwtstate, extack);
893 if (!ret) {
894 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
895 lwtstate_free(lwtstate);
896 }
897
898 return result;
899 }
900
fib_nh_match(struct net * net,struct fib_config * cfg,struct fib_info * fi,struct netlink_ext_ack * extack)901 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
902 struct netlink_ext_ack *extack)
903 {
904 #ifdef CONFIG_IP_ROUTE_MULTIPATH
905 struct rtnexthop *rtnh;
906 int remaining;
907 #endif
908
909 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
910 return 1;
911
912 if (cfg->fc_nh_id) {
913 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
914 return 0;
915 return 1;
916 }
917
918 if (fi->nh) {
919 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
920 return 1;
921 return 0;
922 }
923
924 if (cfg->fc_oif || cfg->fc_gw_family) {
925 struct fib_nh *nh;
926
927 nh = fib_info_nh(fi, 0);
928 if (cfg->fc_encap) {
929 if (fib_encap_match(net, cfg->fc_encap_type,
930 cfg->fc_encap, nh, cfg, extack))
931 return 1;
932 }
933 #ifdef CONFIG_IP_ROUTE_CLASSID
934 if (cfg->fc_flow &&
935 cfg->fc_flow != nh->nh_tclassid)
936 return 1;
937 #endif
938 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
939 (cfg->fc_gw_family &&
940 cfg->fc_gw_family != nh->fib_nh_gw_family))
941 return 1;
942
943 if (cfg->fc_gw_family == AF_INET &&
944 cfg->fc_gw4 != nh->fib_nh_gw4)
945 return 1;
946
947 if (cfg->fc_gw_family == AF_INET6 &&
948 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
949 return 1;
950
951 return 0;
952 }
953
954 #ifdef CONFIG_IP_ROUTE_MULTIPATH
955 if (!cfg->fc_mp)
956 return 0;
957
958 rtnh = cfg->fc_mp;
959 remaining = cfg->fc_mp_len;
960
961 for_nexthops(fi) {
962 int attrlen;
963
964 if (!rtnh_ok(rtnh, remaining))
965 return -EINVAL;
966
967 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
968 return 1;
969
970 attrlen = rtnh_attrlen(rtnh);
971 if (attrlen > 0) {
972 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
973 int err;
974
975 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
976 nlav = nla_find(attrs, attrlen, RTA_VIA);
977 if (nla && nlav) {
978 NL_SET_ERR_MSG(extack,
979 "Nexthop configuration can not contain both GATEWAY and VIA");
980 return -EINVAL;
981 }
982
983 if (nla) {
984 __be32 gw;
985
986 err = fib_gw_from_attr(&gw, nla, extack);
987 if (err)
988 return err;
989
990 if (nh->fib_nh_gw_family != AF_INET ||
991 gw != nh->fib_nh_gw4)
992 return 1;
993 } else if (nlav) {
994 struct fib_config cfg2;
995
996 err = fib_gw_from_via(&cfg2, nlav, extack);
997 if (err)
998 return err;
999
1000 switch (nh->fib_nh_gw_family) {
1001 case AF_INET:
1002 if (cfg2.fc_gw_family != AF_INET ||
1003 cfg2.fc_gw4 != nh->fib_nh_gw4)
1004 return 1;
1005 break;
1006 case AF_INET6:
1007 if (cfg2.fc_gw_family != AF_INET6 ||
1008 ipv6_addr_cmp(&cfg2.fc_gw6,
1009 &nh->fib_nh_gw6))
1010 return 1;
1011 break;
1012 }
1013 }
1014
1015 #ifdef CONFIG_IP_ROUTE_CLASSID
1016 nla = nla_find(attrs, attrlen, RTA_FLOW);
1017 if (nla) {
1018 if (nla_len(nla) < sizeof(u32)) {
1019 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
1020 return -EINVAL;
1021 }
1022 if (nla_get_u32(nla) != nh->nh_tclassid)
1023 return 1;
1024 }
1025 #endif
1026 }
1027
1028 rtnh = rtnh_next(rtnh, &remaining);
1029 } endfor_nexthops(fi);
1030 #endif
1031 return 0;
1032 }
1033
fib_metrics_match(struct fib_config * cfg,struct fib_info * fi)1034 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1035 {
1036 struct nlattr *nla;
1037 int remaining;
1038
1039 if (!cfg->fc_mx)
1040 return true;
1041
1042 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1043 int type = nla_type(nla);
1044 u32 fi_val, val;
1045
1046 if (!type)
1047 continue;
1048 if (type > RTAX_MAX)
1049 return false;
1050
1051 type = array_index_nospec(type, RTAX_MAX + 1);
1052 if (type == RTAX_CC_ALGO) {
1053 char tmp[TCP_CA_NAME_MAX];
1054 bool ecn_ca = false;
1055
1056 nla_strscpy(tmp, nla, sizeof(tmp));
1057 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
1058 } else {
1059 if (nla_len(nla) != sizeof(u32))
1060 return false;
1061 val = nla_get_u32(nla);
1062 }
1063
1064 fi_val = fi->fib_metrics->metrics[type - 1];
1065 if (type == RTAX_FEATURES)
1066 fi_val &= ~DST_FEATURE_ECN_CA;
1067
1068 if (fi_val != val)
1069 return false;
1070 }
1071
1072 return true;
1073 }
1074
fib_check_nh_v6_gw(struct net * net,struct fib_nh * nh,u32 table,struct netlink_ext_ack * extack)1075 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1076 u32 table, struct netlink_ext_ack *extack)
1077 {
1078 struct fib6_config cfg = {
1079 .fc_table = table,
1080 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1081 .fc_ifindex = nh->fib_nh_oif,
1082 .fc_gateway = nh->fib_nh_gw6,
1083 };
1084 struct fib6_nh fib6_nh = {};
1085 int err;
1086
1087 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1088 if (!err) {
1089 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1090 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1091 GFP_KERNEL);
1092 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1093 nh->fib_nh_scope = RT_SCOPE_LINK;
1094
1095 ipv6_stub->fib6_nh_release(&fib6_nh);
1096 }
1097
1098 return err;
1099 }
1100
1101 /*
1102 * Picture
1103 * -------
1104 *
1105 * Semantics of nexthop is very messy by historical reasons.
1106 * We have to take into account, that:
1107 * a) gateway can be actually local interface address,
1108 * so that gatewayed route is direct.
1109 * b) gateway must be on-link address, possibly
1110 * described not by an ifaddr, but also by a direct route.
1111 * c) If both gateway and interface are specified, they should not
1112 * contradict.
1113 * d) If we use tunnel routes, gateway could be not on-link.
1114 *
1115 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1116 * results in pretty ugly and hairy code with obscure logic.
1117 *
1118 * I chose to generalized it instead, so that the size
1119 * of code does not increase practically, but it becomes
1120 * much more general.
1121 * Every prefix is assigned a "scope" value: "host" is local address,
1122 * "link" is direct route,
1123 * [ ... "site" ... "interior" ... ]
1124 * and "universe" is true gateway route with global meaning.
1125 *
1126 * Every prefix refers to a set of "nexthop"s (gw, oif),
1127 * where gw must have narrower scope. This recursion stops
1128 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1129 * which means that gw is forced to be on link.
1130 *
1131 * Code is still hairy, but now it is apparently logically
1132 * consistent and very flexible. F.e. as by-product it allows
1133 * to co-exists in peace independent exterior and interior
1134 * routing processes.
1135 *
1136 * Normally it looks as following.
1137 *
1138 * {universe prefix} -> (gw, oif) [scope link]
1139 * |
1140 * |-> {link prefix} -> (gw, oif) [scope local]
1141 * |
1142 * |-> {local prefix} (terminal node)
1143 */
fib_check_nh_v4_gw(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1144 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1145 u8 scope, struct netlink_ext_ack *extack)
1146 {
1147 struct net_device *dev;
1148 struct fib_result res;
1149 int err = 0;
1150
1151 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1152 unsigned int addr_type;
1153
1154 if (scope >= RT_SCOPE_LINK) {
1155 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1156 return -EINVAL;
1157 }
1158 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1159 if (!dev) {
1160 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1161 return -ENODEV;
1162 }
1163 if (!(dev->flags & IFF_UP)) {
1164 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1165 return -ENETDOWN;
1166 }
1167 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1168 if (addr_type != RTN_UNICAST) {
1169 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1170 return -EINVAL;
1171 }
1172 if (!netif_carrier_ok(dev))
1173 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1174 nh->fib_nh_dev = dev;
1175 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1176 nh->fib_nh_scope = RT_SCOPE_LINK;
1177 return 0;
1178 }
1179 rcu_read_lock();
1180 {
1181 struct fib_table *tbl = NULL;
1182 struct flowi4 fl4 = {
1183 .daddr = nh->fib_nh_gw4,
1184 .flowi4_scope = scope + 1,
1185 .flowi4_oif = nh->fib_nh_oif,
1186 .flowi4_iif = LOOPBACK_IFINDEX,
1187 };
1188
1189 /* It is not necessary, but requires a bit of thinking */
1190 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1191 fl4.flowi4_scope = RT_SCOPE_LINK;
1192
1193 if (table && table != RT_TABLE_MAIN)
1194 tbl = fib_get_table(net, table);
1195
1196 if (tbl)
1197 err = fib_table_lookup(tbl, &fl4, &res,
1198 FIB_LOOKUP_IGNORE_LINKSTATE |
1199 FIB_LOOKUP_NOREF);
1200
1201 /* on error or if no table given do full lookup. This
1202 * is needed for example when nexthops are in the local
1203 * table rather than the given table
1204 */
1205 if (!tbl || err) {
1206 err = fib_lookup(net, &fl4, &res,
1207 FIB_LOOKUP_IGNORE_LINKSTATE);
1208 }
1209
1210 if (err) {
1211 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1212 goto out;
1213 }
1214 }
1215
1216 err = -EINVAL;
1217 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1218 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1219 goto out;
1220 }
1221 nh->fib_nh_scope = res.scope;
1222 nh->fib_nh_oif = FIB_RES_OIF(res);
1223 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1224 if (!dev) {
1225 NL_SET_ERR_MSG(extack,
1226 "No egress device for nexthop gateway");
1227 goto out;
1228 }
1229 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1230 if (!netif_carrier_ok(dev))
1231 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1232 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1233 out:
1234 rcu_read_unlock();
1235 return err;
1236 }
1237
fib_check_nh_nongw(struct net * net,struct fib_nh * nh,struct netlink_ext_ack * extack)1238 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1239 struct netlink_ext_ack *extack)
1240 {
1241 struct in_device *in_dev;
1242 int err;
1243
1244 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1245 NL_SET_ERR_MSG(extack,
1246 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1247 return -EINVAL;
1248 }
1249
1250 rcu_read_lock();
1251
1252 err = -ENODEV;
1253 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1254 if (!in_dev)
1255 goto out;
1256 err = -ENETDOWN;
1257 if (!(in_dev->dev->flags & IFF_UP)) {
1258 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1259 goto out;
1260 }
1261
1262 nh->fib_nh_dev = in_dev->dev;
1263 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1264 nh->fib_nh_scope = RT_SCOPE_HOST;
1265 if (!netif_carrier_ok(nh->fib_nh_dev))
1266 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1267 err = 0;
1268 out:
1269 rcu_read_unlock();
1270 return err;
1271 }
1272
fib_check_nh(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1273 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1274 struct netlink_ext_ack *extack)
1275 {
1276 int err;
1277
1278 if (nh->fib_nh_gw_family == AF_INET)
1279 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1280 else if (nh->fib_nh_gw_family == AF_INET6)
1281 err = fib_check_nh_v6_gw(net, nh, table, extack);
1282 else
1283 err = fib_check_nh_nongw(net, nh, extack);
1284
1285 return err;
1286 }
1287
fib_info_update_nhc_saddr(struct net * net,struct fib_nh_common * nhc,unsigned char scope)1288 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1289 unsigned char scope)
1290 {
1291 struct fib_nh *nh;
1292 __be32 saddr;
1293
1294 if (nhc->nhc_family != AF_INET)
1295 return inet_select_addr(nhc->nhc_dev, 0, scope);
1296
1297 nh = container_of(nhc, struct fib_nh, nh_common);
1298 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1299
1300 WRITE_ONCE(nh->nh_saddr, saddr);
1301 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid));
1302
1303 return saddr;
1304 }
1305
fib_result_prefsrc(struct net * net,struct fib_result * res)1306 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1307 {
1308 struct fib_nh_common *nhc = res->nhc;
1309
1310 if (res->fi->fib_prefsrc)
1311 return res->fi->fib_prefsrc;
1312
1313 if (nhc->nhc_family == AF_INET) {
1314 struct fib_nh *nh;
1315
1316 nh = container_of(nhc, struct fib_nh, nh_common);
1317 if (READ_ONCE(nh->nh_saddr_genid) ==
1318 atomic_read(&net->ipv4.dev_addr_genid))
1319 return READ_ONCE(nh->nh_saddr);
1320 }
1321
1322 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1323 }
1324
fib_valid_prefsrc(struct fib_config * cfg,__be32 fib_prefsrc)1325 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1326 {
1327 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1328 fib_prefsrc != cfg->fc_dst) {
1329 u32 tb_id = cfg->fc_table;
1330 int rc;
1331
1332 if (tb_id == RT_TABLE_MAIN)
1333 tb_id = RT_TABLE_LOCAL;
1334
1335 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1336 fib_prefsrc, tb_id);
1337
1338 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1339 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1340 fib_prefsrc, RT_TABLE_LOCAL);
1341 }
1342
1343 if (rc != RTN_LOCAL)
1344 return false;
1345 }
1346 return true;
1347 }
1348
fib_create_info(struct fib_config * cfg,struct netlink_ext_ack * extack)1349 struct fib_info *fib_create_info(struct fib_config *cfg,
1350 struct netlink_ext_ack *extack)
1351 {
1352 int err;
1353 struct fib_info *fi = NULL;
1354 struct nexthop *nh = NULL;
1355 struct fib_info *ofi;
1356 int nhs = 1;
1357 struct net *net = cfg->fc_nlinfo.nl_net;
1358
1359 ASSERT_RTNL();
1360 if (cfg->fc_type > RTN_MAX)
1361 goto err_inval;
1362
1363 /* Fast check to catch the most weird cases */
1364 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1365 NL_SET_ERR_MSG(extack, "Invalid scope");
1366 goto err_inval;
1367 }
1368
1369 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1370 NL_SET_ERR_MSG(extack,
1371 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1372 goto err_inval;
1373 }
1374
1375 if (cfg->fc_nh_id) {
1376 if (!cfg->fc_mx) {
1377 fi = fib_find_info_nh(net, cfg);
1378 if (fi) {
1379 refcount_inc(&fi->fib_treeref);
1380 return fi;
1381 }
1382 }
1383
1384 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1385 if (!nh) {
1386 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1387 goto err_inval;
1388 }
1389 nhs = 0;
1390 }
1391
1392 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1393 if (cfg->fc_mp) {
1394 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1395 if (nhs == 0)
1396 goto err_inval;
1397 }
1398 #endif
1399
1400 fib_info_hash_grow(net);
1401
1402 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1403 if (!fi) {
1404 err = -ENOBUFS;
1405 goto failure;
1406 }
1407
1408 fi->fib_metrics = ip_fib_metrics_init(cfg->fc_mx, cfg->fc_mx_len, extack);
1409 if (IS_ERR(fi->fib_metrics)) {
1410 err = PTR_ERR(fi->fib_metrics);
1411 kfree(fi);
1412 return ERR_PTR(err);
1413 }
1414
1415 fi->fib_net = net;
1416 fi->fib_protocol = cfg->fc_protocol;
1417 fi->fib_scope = cfg->fc_scope;
1418 fi->fib_flags = cfg->fc_flags;
1419 fi->fib_priority = cfg->fc_priority;
1420 fi->fib_prefsrc = cfg->fc_prefsrc;
1421 fi->fib_type = cfg->fc_type;
1422 fi->fib_tb_id = cfg->fc_table;
1423
1424 fi->fib_nhs = nhs;
1425 if (nh) {
1426 if (!nexthop_get(nh)) {
1427 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1428 err = -EINVAL;
1429 } else {
1430 err = 0;
1431 fi->nh = nh;
1432 }
1433 } else {
1434 change_nexthops(fi) {
1435 nexthop_nh->nh_parent = fi;
1436 } endfor_nexthops(fi)
1437
1438 if (cfg->fc_mp)
1439 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1440 extack);
1441 else
1442 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1443 }
1444
1445 if (err != 0)
1446 goto failure;
1447
1448 if (fib_props[cfg->fc_type].error) {
1449 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1450 NL_SET_ERR_MSG(extack,
1451 "Gateway, device and multipath can not be specified for this route type");
1452 goto err_inval;
1453 }
1454 goto link_it;
1455 } else {
1456 switch (cfg->fc_type) {
1457 case RTN_UNICAST:
1458 case RTN_LOCAL:
1459 case RTN_BROADCAST:
1460 case RTN_ANYCAST:
1461 case RTN_MULTICAST:
1462 break;
1463 default:
1464 NL_SET_ERR_MSG(extack, "Invalid route type");
1465 goto err_inval;
1466 }
1467 }
1468
1469 if (cfg->fc_scope > RT_SCOPE_HOST) {
1470 NL_SET_ERR_MSG(extack, "Invalid scope");
1471 goto err_inval;
1472 }
1473
1474 if (fi->nh) {
1475 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1476 if (err)
1477 goto failure;
1478 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1479 struct fib_nh *nh = fi->fib_nh;
1480
1481 /* Local address is added. */
1482 if (nhs != 1) {
1483 NL_SET_ERR_MSG(extack,
1484 "Route with host scope can not have multiple nexthops");
1485 goto err_inval;
1486 }
1487 if (nh->fib_nh_gw_family) {
1488 NL_SET_ERR_MSG(extack,
1489 "Route with host scope can not have a gateway");
1490 goto err_inval;
1491 }
1492 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1493 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1494 err = -ENODEV;
1495 if (!nh->fib_nh_dev)
1496 goto failure;
1497 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1498 GFP_KERNEL);
1499 } else {
1500 int linkdown = 0;
1501
1502 change_nexthops(fi) {
1503 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1504 cfg->fc_table, cfg->fc_scope,
1505 extack);
1506 if (err != 0)
1507 goto failure;
1508 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1509 linkdown++;
1510 } endfor_nexthops(fi)
1511 if (linkdown == fi->fib_nhs)
1512 fi->fib_flags |= RTNH_F_LINKDOWN;
1513 }
1514
1515 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1516 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1517 goto err_inval;
1518 }
1519
1520 if (!fi->nh) {
1521 change_nexthops(fi) {
1522 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1523 fi->fib_scope);
1524 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1525 fi->fib_nh_is_v6 = true;
1526 } endfor_nexthops(fi)
1527
1528 fib_rebalance(fi);
1529 }
1530
1531 link_it:
1532 ofi = fib_find_info(fi);
1533 if (ofi) {
1534 /* fib_table_lookup() should not see @fi yet. */
1535 fi->fib_dead = 1;
1536 free_fib_info(fi);
1537 refcount_inc(&ofi->fib_treeref);
1538 return ofi;
1539 }
1540
1541 refcount_set(&fi->fib_treeref, 1);
1542 refcount_set(&fi->fib_clntref, 1);
1543
1544 net->ipv4.fib_info_cnt++;
1545 hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi));
1546
1547 if (fi->fib_prefsrc) {
1548 struct hlist_head *head;
1549
1550 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc);
1551 hlist_add_head(&fi->fib_lhash, head);
1552 }
1553 if (fi->nh) {
1554 list_add(&fi->nh_list, &nh->fi_list);
1555 } else {
1556 change_nexthops(fi) {
1557 struct hlist_head *head;
1558
1559 if (!nexthop_nh->fib_nh_dev)
1560 continue;
1561 head = fib_nh_head(nexthop_nh->fib_nh_dev);
1562 hlist_add_head_rcu(&nexthop_nh->nh_hash, head);
1563 } endfor_nexthops(fi)
1564 }
1565 return fi;
1566
1567 err_inval:
1568 err = -EINVAL;
1569
1570 failure:
1571 if (fi) {
1572 /* fib_table_lookup() should not see @fi yet. */
1573 fi->fib_dead = 1;
1574 free_fib_info(fi);
1575 }
1576
1577 return ERR_PTR(err);
1578 }
1579
fib_nexthop_info(struct sk_buff * skb,const struct fib_nh_common * nhc,u8 rt_family,unsigned char * flags,bool skip_oif)1580 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1581 u8 rt_family, unsigned char *flags, bool skip_oif)
1582 {
1583 if (nhc->nhc_flags & RTNH_F_DEAD)
1584 *flags |= RTNH_F_DEAD;
1585
1586 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1587 *flags |= RTNH_F_LINKDOWN;
1588
1589 rcu_read_lock();
1590 switch (nhc->nhc_family) {
1591 case AF_INET:
1592 if (ip_ignore_linkdown(nhc->nhc_dev))
1593 *flags |= RTNH_F_DEAD;
1594 break;
1595 case AF_INET6:
1596 if (ip6_ignore_linkdown(nhc->nhc_dev))
1597 *flags |= RTNH_F_DEAD;
1598 break;
1599 }
1600 rcu_read_unlock();
1601 }
1602
1603 switch (nhc->nhc_gw_family) {
1604 case AF_INET:
1605 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1606 goto nla_put_failure;
1607 break;
1608 case AF_INET6:
1609 /* if gateway family does not match nexthop family
1610 * gateway is encoded as RTA_VIA
1611 */
1612 if (rt_family != nhc->nhc_gw_family) {
1613 int alen = sizeof(struct in6_addr);
1614 struct nlattr *nla;
1615 struct rtvia *via;
1616
1617 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1618 if (!nla)
1619 goto nla_put_failure;
1620
1621 via = nla_data(nla);
1622 via->rtvia_family = AF_INET6;
1623 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1624 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1625 &nhc->nhc_gw.ipv6) < 0) {
1626 goto nla_put_failure;
1627 }
1628 break;
1629 }
1630
1631 *flags |= (nhc->nhc_flags &
1632 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1633
1634 if (!skip_oif && nhc->nhc_dev &&
1635 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1636 goto nla_put_failure;
1637
1638 if (lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1639 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1640 goto nla_put_failure;
1641
1642 return 0;
1643
1644 nla_put_failure:
1645 return -EMSGSIZE;
1646 }
1647 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1648
1649 #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)1650 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1651 int nh_weight, u8 rt_family, u32 nh_tclassid)
1652 {
1653 const struct net_device *dev = nhc->nhc_dev;
1654 struct rtnexthop *rtnh;
1655 unsigned char flags = 0;
1656
1657 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1658 if (!rtnh)
1659 goto nla_put_failure;
1660
1661 rtnh->rtnh_hops = nh_weight - 1;
1662 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1663
1664 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1665 goto nla_put_failure;
1666
1667 rtnh->rtnh_flags = flags;
1668
1669 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1670 goto nla_put_failure;
1671
1672 /* length of rtnetlink header + attributes */
1673 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1674
1675 return 0;
1676
1677 nla_put_failure:
1678 return -EMSGSIZE;
1679 }
1680 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1681 #endif
1682
1683 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1684 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1685 {
1686 struct nlattr *mp;
1687
1688 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1689 if (!mp)
1690 goto nla_put_failure;
1691
1692 if (unlikely(fi->nh)) {
1693 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1694 goto nla_put_failure;
1695 goto mp_end;
1696 }
1697
1698 for_nexthops(fi) {
1699 u32 nh_tclassid = 0;
1700 #ifdef CONFIG_IP_ROUTE_CLASSID
1701 nh_tclassid = nh->nh_tclassid;
1702 #endif
1703 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1704 AF_INET, nh_tclassid) < 0)
1705 goto nla_put_failure;
1706 } endfor_nexthops(fi);
1707
1708 mp_end:
1709 nla_nest_end(skb, mp);
1710
1711 return 0;
1712
1713 nla_put_failure:
1714 return -EMSGSIZE;
1715 }
1716 #else
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1717 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1718 {
1719 return 0;
1720 }
1721 #endif
1722
fib_dump_info(struct sk_buff * skb,u32 portid,u32 seq,int event,const struct fib_rt_info * fri,unsigned int flags)1723 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1724 const struct fib_rt_info *fri, unsigned int flags)
1725 {
1726 unsigned int nhs = fib_info_num_path(fri->fi);
1727 struct fib_info *fi = fri->fi;
1728 u32 tb_id = fri->tb_id;
1729 struct nlmsghdr *nlh;
1730 struct rtmsg *rtm;
1731
1732 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1733 if (!nlh)
1734 return -EMSGSIZE;
1735
1736 rtm = nlmsg_data(nlh);
1737 rtm->rtm_family = AF_INET;
1738 rtm->rtm_dst_len = fri->dst_len;
1739 rtm->rtm_src_len = 0;
1740 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp);
1741 if (tb_id < 256)
1742 rtm->rtm_table = tb_id;
1743 else
1744 rtm->rtm_table = RT_TABLE_COMPAT;
1745 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1746 goto nla_put_failure;
1747 rtm->rtm_type = fri->type;
1748 rtm->rtm_flags = fi->fib_flags;
1749 rtm->rtm_scope = fi->fib_scope;
1750 rtm->rtm_protocol = fi->fib_protocol;
1751
1752 if (rtm->rtm_dst_len &&
1753 nla_put_in_addr(skb, RTA_DST, fri->dst))
1754 goto nla_put_failure;
1755 if (fi->fib_priority &&
1756 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1757 goto nla_put_failure;
1758 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1759 goto nla_put_failure;
1760
1761 if (fi->fib_prefsrc &&
1762 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1763 goto nla_put_failure;
1764
1765 if (fi->nh) {
1766 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1767 goto nla_put_failure;
1768 if (nexthop_is_blackhole(fi->nh))
1769 rtm->rtm_type = RTN_BLACKHOLE;
1770 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
1771 goto offload;
1772 }
1773
1774 if (nhs == 1) {
1775 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1776 unsigned char flags = 0;
1777
1778 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1779 goto nla_put_failure;
1780
1781 rtm->rtm_flags = flags;
1782 #ifdef CONFIG_IP_ROUTE_CLASSID
1783 if (nhc->nhc_family == AF_INET) {
1784 struct fib_nh *nh;
1785
1786 nh = container_of(nhc, struct fib_nh, nh_common);
1787 if (nh->nh_tclassid &&
1788 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1789 goto nla_put_failure;
1790 }
1791 #endif
1792 } else {
1793 if (fib_add_multipath(skb, fi) < 0)
1794 goto nla_put_failure;
1795 }
1796
1797 offload:
1798 if (fri->offload)
1799 rtm->rtm_flags |= RTM_F_OFFLOAD;
1800 if (fri->trap)
1801 rtm->rtm_flags |= RTM_F_TRAP;
1802 if (fri->offload_failed)
1803 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1804
1805 nlmsg_end(skb, nlh);
1806 return 0;
1807
1808 nla_put_failure:
1809 nlmsg_cancel(skb, nlh);
1810 return -EMSGSIZE;
1811 }
1812
1813 /*
1814 * Update FIB if:
1815 * - local address disappeared -> we must delete all the entries
1816 * referring to it.
1817 * - device went down -> we must shutdown all nexthops going via it.
1818 */
fib_sync_down_addr(struct net_device * dev,__be32 local)1819 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1820 {
1821 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1822 struct net *net = dev_net(dev);
1823 struct hlist_head *head;
1824 struct fib_info *fi;
1825 int ret = 0;
1826
1827 if (!local)
1828 return 0;
1829
1830 head = fib_info_laddrhash_bucket(net, local);
1831 hlist_for_each_entry(fi, head, fib_lhash) {
1832 if (!net_eq(fi->fib_net, net) ||
1833 fi->fib_tb_id != tb_id)
1834 continue;
1835 if (fi->fib_prefsrc == local) {
1836 fi->fib_flags |= RTNH_F_DEAD;
1837 fi->pfsrc_removed = true;
1838 ret++;
1839 }
1840 }
1841 return ret;
1842 }
1843
call_fib_nh_notifiers(struct fib_nh * nh,enum fib_event_type event_type)1844 static int call_fib_nh_notifiers(struct fib_nh *nh,
1845 enum fib_event_type event_type)
1846 {
1847 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1848 struct fib_nh_notifier_info info = {
1849 .fib_nh = nh,
1850 };
1851
1852 switch (event_type) {
1853 case FIB_EVENT_NH_ADD:
1854 if (nh->fib_nh_flags & RTNH_F_DEAD)
1855 break;
1856 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1857 break;
1858 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1859 &info.info);
1860 case FIB_EVENT_NH_DEL:
1861 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1862 (nh->fib_nh_flags & RTNH_F_DEAD))
1863 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1864 event_type, &info.info);
1865 break;
1866 default:
1867 break;
1868 }
1869
1870 return NOTIFY_DONE;
1871 }
1872
1873 /* Update the PMTU of exceptions when:
1874 * - the new MTU of the first hop becomes smaller than the PMTU
1875 * - the old MTU was the same as the PMTU, and it limited discovery of
1876 * larger MTUs on the path. With that limit raised, we can now
1877 * discover larger MTUs
1878 * A special case is locked exceptions, for which the PMTU is smaller
1879 * than the minimal accepted PMTU:
1880 * - if the new MTU is greater than the PMTU, don't make any change
1881 * - otherwise, unlock and set PMTU
1882 */
fib_nhc_update_mtu(struct fib_nh_common * nhc,u32 new,u32 orig)1883 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1884 {
1885 struct fnhe_hash_bucket *bucket;
1886 int i;
1887
1888 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1889 if (!bucket)
1890 return;
1891
1892 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1893 struct fib_nh_exception *fnhe;
1894
1895 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1896 fnhe;
1897 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1898 if (fnhe->fnhe_mtu_locked) {
1899 if (new <= fnhe->fnhe_pmtu) {
1900 fnhe->fnhe_pmtu = new;
1901 fnhe->fnhe_mtu_locked = false;
1902 }
1903 } else if (new < fnhe->fnhe_pmtu ||
1904 orig == fnhe->fnhe_pmtu) {
1905 fnhe->fnhe_pmtu = new;
1906 }
1907 }
1908 }
1909 }
1910
fib_sync_mtu(struct net_device * dev,u32 orig_mtu)1911 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1912 {
1913 struct hlist_head *head = fib_nh_head(dev);
1914 struct fib_nh *nh;
1915
1916 hlist_for_each_entry(nh, head, nh_hash) {
1917 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
1918 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1919 }
1920 }
1921
1922 /* Event force Flags Description
1923 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1924 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1925 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1926 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1927 *
1928 * only used when fib_nh is built into fib_info
1929 */
fib_sync_down_dev(struct net_device * dev,unsigned long event,bool force)1930 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1931 {
1932 struct hlist_head *head = fib_nh_head(dev);
1933 struct fib_info *prev_fi = NULL;
1934 int scope = RT_SCOPE_NOWHERE;
1935 struct fib_nh *nh;
1936 int ret = 0;
1937
1938 if (force)
1939 scope = -1;
1940
1941 hlist_for_each_entry(nh, head, nh_hash) {
1942 struct fib_info *fi = nh->nh_parent;
1943 int dead;
1944
1945 BUG_ON(!fi->fib_nhs);
1946 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
1947 if (fi == prev_fi)
1948 continue;
1949 prev_fi = fi;
1950 dead = 0;
1951 change_nexthops(fi) {
1952 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1953 dead++;
1954 else if (nexthop_nh->fib_nh_dev == dev &&
1955 nexthop_nh->fib_nh_scope != scope) {
1956 switch (event) {
1957 case NETDEV_DOWN:
1958 case NETDEV_UNREGISTER:
1959 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1960 fallthrough;
1961 case NETDEV_CHANGE:
1962 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1963 break;
1964 }
1965 call_fib_nh_notifiers(nexthop_nh,
1966 FIB_EVENT_NH_DEL);
1967 dead++;
1968 }
1969 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1970 if (event == NETDEV_UNREGISTER &&
1971 nexthop_nh->fib_nh_dev == dev) {
1972 dead = fi->fib_nhs;
1973 break;
1974 }
1975 #endif
1976 } endfor_nexthops(fi)
1977 if (dead == fi->fib_nhs) {
1978 switch (event) {
1979 case NETDEV_DOWN:
1980 case NETDEV_UNREGISTER:
1981 fi->fib_flags |= RTNH_F_DEAD;
1982 fallthrough;
1983 case NETDEV_CHANGE:
1984 fi->fib_flags |= RTNH_F_LINKDOWN;
1985 break;
1986 }
1987 ret++;
1988 }
1989
1990 fib_rebalance(fi);
1991 }
1992
1993 return ret;
1994 }
1995
1996 /* Must be invoked inside of an RCU protected region. */
fib_select_default(const struct flowi4 * flp,struct fib_result * res)1997 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1998 {
1999 struct fib_info *fi = NULL, *last_resort = NULL;
2000 struct hlist_head *fa_head = res->fa_head;
2001 struct fib_table *tb = res->table;
2002 u8 slen = 32 - res->prefixlen;
2003 int order = -1, last_idx = -1;
2004 struct fib_alias *fa, *fa1 = NULL;
2005 u32 last_prio = res->fi->fib_priority;
2006 dscp_t last_dscp = 0;
2007
2008 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2009 struct fib_info *next_fi = fa->fa_info;
2010 struct fib_nh_common *nhc;
2011
2012 if (fa->fa_slen != slen)
2013 continue;
2014 if (fa->fa_dscp && !fib_dscp_masked_match(fa->fa_dscp, flp))
2015 continue;
2016 if (fa->tb_id != tb->tb_id)
2017 continue;
2018 if (next_fi->fib_priority > last_prio &&
2019 fa->fa_dscp == last_dscp) {
2020 if (last_dscp)
2021 continue;
2022 break;
2023 }
2024 if (next_fi->fib_flags & RTNH_F_DEAD)
2025 continue;
2026 last_dscp = fa->fa_dscp;
2027 last_prio = next_fi->fib_priority;
2028
2029 if (next_fi->fib_scope != res->scope ||
2030 fa->fa_type != RTN_UNICAST)
2031 continue;
2032
2033 nhc = fib_info_nhc(next_fi, 0);
2034 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2035 continue;
2036
2037 fib_alias_accessed(fa);
2038
2039 if (!fi) {
2040 if (next_fi != res->fi)
2041 break;
2042 fa1 = fa;
2043 } else if (!fib_detect_death(fi, order, &last_resort,
2044 &last_idx, fa1->fa_default)) {
2045 fib_result_assign(res, fi);
2046 fa1->fa_default = order;
2047 goto out;
2048 }
2049 fi = next_fi;
2050 order++;
2051 }
2052
2053 if (order <= 0 || !fi) {
2054 if (fa1)
2055 fa1->fa_default = -1;
2056 goto out;
2057 }
2058
2059 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2060 fa1->fa_default)) {
2061 fib_result_assign(res, fi);
2062 fa1->fa_default = order;
2063 goto out;
2064 }
2065
2066 if (last_idx >= 0)
2067 fib_result_assign(res, last_resort);
2068 fa1->fa_default = last_idx;
2069 out:
2070 return;
2071 }
2072
2073 /*
2074 * Dead device goes up. We wake up dead nexthops.
2075 * It takes sense only on multipath routes.
2076 *
2077 * only used when fib_nh is built into fib_info
2078 */
fib_sync_up(struct net_device * dev,unsigned char nh_flags)2079 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2080 {
2081 struct fib_info *prev_fi;
2082 struct hlist_head *head;
2083 struct fib_nh *nh;
2084 int ret;
2085
2086 if (!(dev->flags & IFF_UP))
2087 return 0;
2088
2089 if (nh_flags & RTNH_F_DEAD) {
2090 unsigned int flags = netif_get_flags(dev);
2091
2092 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2093 nh_flags |= RTNH_F_LINKDOWN;
2094 }
2095
2096 prev_fi = NULL;
2097 head = fib_nh_head(dev);
2098 ret = 0;
2099
2100 hlist_for_each_entry(nh, head, nh_hash) {
2101 struct fib_info *fi = nh->nh_parent;
2102 int alive;
2103
2104 BUG_ON(!fi->fib_nhs);
2105 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
2106 if (fi == prev_fi)
2107 continue;
2108
2109 prev_fi = fi;
2110 alive = 0;
2111 change_nexthops(fi) {
2112 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2113 alive++;
2114 continue;
2115 }
2116 if (!nexthop_nh->fib_nh_dev ||
2117 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2118 continue;
2119 if (nexthop_nh->fib_nh_dev != dev ||
2120 !__in_dev_get_rtnl(dev))
2121 continue;
2122 alive++;
2123 nexthop_nh->fib_nh_flags &= ~nh_flags;
2124 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2125 } endfor_nexthops(fi)
2126
2127 if (alive > 0) {
2128 fi->fib_flags &= ~nh_flags;
2129 ret++;
2130 }
2131
2132 fib_rebalance(fi);
2133 }
2134
2135 return ret;
2136 }
2137
2138 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_good_nh(const struct fib_nh * nh)2139 static bool fib_good_nh(const struct fib_nh *nh)
2140 {
2141 int state = NUD_REACHABLE;
2142
2143 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2144 struct neighbour *n;
2145
2146 rcu_read_lock();
2147
2148 if (likely(nh->fib_nh_gw_family == AF_INET))
2149 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2150 (__force u32)nh->fib_nh_gw4);
2151 else if (nh->fib_nh_gw_family == AF_INET6)
2152 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2153 &nh->fib_nh_gw6);
2154 else
2155 n = NULL;
2156 if (n)
2157 state = READ_ONCE(n->nud_state);
2158
2159 rcu_read_unlock();
2160 }
2161
2162 return !!(state & NUD_VALID);
2163 }
2164
fib_select_multipath(struct fib_result * res,int hash,const struct flowi4 * fl4)2165 void fib_select_multipath(struct fib_result *res, int hash,
2166 const struct flowi4 *fl4)
2167 {
2168 struct fib_info *fi = res->fi;
2169 struct net *net = fi->fib_net;
2170 bool found = false;
2171 bool use_neigh;
2172 __be32 saddr;
2173
2174 if (unlikely(res->fi->nh)) {
2175 nexthop_path_fib_result(res, hash);
2176 return;
2177 }
2178
2179 use_neigh = READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh);
2180 saddr = fl4 ? fl4->saddr : 0;
2181
2182 change_nexthops(fi) {
2183 int nh_upper_bound;
2184
2185 /* Nexthops without a carrier are assigned an upper bound of
2186 * minus one when "ignore_routes_with_linkdown" is set.
2187 */
2188 nh_upper_bound = atomic_read(&nexthop_nh->fib_nh_upper_bound);
2189 if (nh_upper_bound == -1 ||
2190 (use_neigh && !fib_good_nh(nexthop_nh)))
2191 continue;
2192
2193 if (!found) {
2194 res->nh_sel = nhsel;
2195 res->nhc = &nexthop_nh->nh_common;
2196 found = !saddr || nexthop_nh->nh_saddr == saddr;
2197 }
2198
2199 if (hash > nh_upper_bound)
2200 continue;
2201
2202 if (!saddr || nexthop_nh->nh_saddr == saddr) {
2203 res->nh_sel = nhsel;
2204 res->nhc = &nexthop_nh->nh_common;
2205 return;
2206 }
2207
2208 if (found)
2209 return;
2210
2211 } endfor_nexthops(fi);
2212 }
2213 #endif
2214
fib_select_path(struct net * net,struct fib_result * res,struct flowi4 * fl4,const struct sk_buff * skb)2215 void fib_select_path(struct net *net, struct fib_result *res,
2216 struct flowi4 *fl4, const struct sk_buff *skb)
2217 {
2218 if (fl4->flowi4_oif)
2219 goto check_saddr;
2220
2221 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2222 if (fib_info_num_path(res->fi) > 1) {
2223 int h = fib_multipath_hash(net, fl4, skb, NULL);
2224
2225 fib_select_multipath(res, h, fl4);
2226 }
2227 else
2228 #endif
2229 if (!res->prefixlen &&
2230 res->table->tb_num_default > 1 &&
2231 res->type == RTN_UNICAST)
2232 fib_select_default(fl4, res);
2233
2234 check_saddr:
2235 if (!fl4->saddr) {
2236 struct net_device *l3mdev;
2237
2238 l3mdev = dev_get_by_index_rcu(net, fl4->flowi4_l3mdev);
2239
2240 if (!l3mdev ||
2241 l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) == l3mdev)
2242 fl4->saddr = fib_result_prefsrc(net, res);
2243 else
2244 fl4->saddr = inet_select_addr(l3mdev, 0, RT_SCOPE_LINK);
2245 }
2246 }
2247
fib4_semantics_init(struct net * net)2248 int __net_init fib4_semantics_init(struct net *net)
2249 {
2250 unsigned int hash_bits = 4;
2251
2252 net->ipv4.fib_info_hash = fib_info_hash_alloc(hash_bits);
2253 if (!net->ipv4.fib_info_hash)
2254 return -ENOMEM;
2255
2256 net->ipv4.fib_info_hash_bits = hash_bits;
2257 net->ipv4.fib_info_cnt = 0;
2258
2259 return 0;
2260 }
2261
fib4_semantics_exit(struct net * net)2262 void __net_exit fib4_semantics_exit(struct net *net)
2263 {
2264 fib_info_hash_free(net->ipv4.fib_info_hash);
2265 }
2266