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 kvzalloc_objs(struct hlist_head, (1 << hash_bits) * 2);
369 }
370
fib_info_hash_free(struct hlist_head * head)371 static void fib_info_hash_free(struct hlist_head *head)
372 {
373 kvfree(head);
374 }
375
fib_info_hash_grow(struct net * net)376 static void fib_info_hash_grow(struct net *net)
377 {
378 unsigned int old_size = 1 << net->ipv4.fib_info_hash_bits;
379 struct hlist_head *new_info_hash, *old_info_hash;
380 unsigned int i;
381
382 if (net->ipv4.fib_info_cnt < old_size)
383 return;
384
385 new_info_hash = fib_info_hash_alloc(net->ipv4.fib_info_hash_bits + 1);
386 if (!new_info_hash)
387 return;
388
389 old_info_hash = net->ipv4.fib_info_hash;
390 net->ipv4.fib_info_hash = new_info_hash;
391 net->ipv4.fib_info_hash_bits += 1;
392
393 for (i = 0; i < old_size; i++) {
394 struct hlist_head *head = &old_info_hash[i];
395 struct hlist_node *n;
396 struct fib_info *fi;
397
398 hlist_for_each_entry_safe(fi, n, head, fib_hash)
399 hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi));
400 }
401
402 for (i = 0; i < old_size; i++) {
403 struct hlist_head *lhead = &old_info_hash[old_size + i];
404 struct hlist_node *n;
405 struct fib_info *fi;
406
407 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash)
408 hlist_add_head(&fi->fib_lhash,
409 fib_info_laddrhash_bucket(fi->fib_net,
410 fi->fib_prefsrc));
411 }
412
413 fib_info_hash_free(old_info_hash);
414 }
415
416 /* no metrics, only nexthop id */
fib_find_info_nh(struct net * net,const struct fib_config * cfg)417 static struct fib_info *fib_find_info_nh(struct net *net,
418 const struct fib_config *cfg)
419 {
420 struct hlist_head *head;
421 struct fib_info *fi;
422 unsigned int hash;
423
424 hash = fib_info_hashfn_1(cfg->fc_nh_id,
425 cfg->fc_protocol, cfg->fc_scope,
426 (__force u32)cfg->fc_prefsrc,
427 cfg->fc_priority);
428 hash = fib_info_hashfn_result(net, hash);
429 head = &net->ipv4.fib_info_hash[hash];
430
431 hlist_for_each_entry(fi, head, fib_hash) {
432 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
433 continue;
434
435 if (cfg->fc_protocol == fi->fib_protocol &&
436 cfg->fc_scope == fi->fib_scope &&
437 cfg->fc_prefsrc == fi->fib_prefsrc &&
438 cfg->fc_priority == fi->fib_priority &&
439 cfg->fc_type == fi->fib_type &&
440 cfg->fc_table == fi->fib_tb_id &&
441 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
442 return fi;
443 }
444
445 return NULL;
446 }
447
fib_find_info(struct fib_info * nfi)448 static struct fib_info *fib_find_info(struct fib_info *nfi)
449 {
450 struct hlist_head *head = fib_info_hash_bucket(nfi);
451 struct fib_info *fi;
452
453 hlist_for_each_entry(fi, head, fib_hash) {
454 if (fi->fib_nhs != nfi->fib_nhs)
455 continue;
456
457 if (nfi->fib_protocol == fi->fib_protocol &&
458 nfi->fib_scope == fi->fib_scope &&
459 nfi->fib_prefsrc == fi->fib_prefsrc &&
460 nfi->fib_priority == fi->fib_priority &&
461 nfi->fib_type == fi->fib_type &&
462 nfi->fib_tb_id == fi->fib_tb_id &&
463 memcmp(nfi->fib_metrics, fi->fib_metrics,
464 sizeof(u32) * RTAX_MAX) == 0 &&
465 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
466 nh_comp(fi, nfi) == 0)
467 return fi;
468 }
469
470 return NULL;
471 }
472
473 /* Check, that the gateway is already configured.
474 * Used only by redirect accept routine, under rcu_read_lock();
475 */
ip_fib_check_default(__be32 gw,struct net_device * dev)476 int ip_fib_check_default(__be32 gw, struct net_device *dev)
477 {
478 struct hlist_head *head;
479 struct fib_nh *nh;
480
481 head = fib_nh_head(dev);
482
483 hlist_for_each_entry_rcu(nh, head, nh_hash) {
484 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
485 if (nh->fib_nh_gw4 == gw &&
486 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
487 return 0;
488 }
489 }
490
491 return -1;
492 }
493
fib_nlmsg_size(struct fib_info * fi)494 size_t fib_nlmsg_size(struct fib_info *fi)
495 {
496 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
497 + nla_total_size(4) /* RTA_TABLE */
498 + nla_total_size(4) /* RTA_DST */
499 + nla_total_size(4) /* RTA_PRIORITY */
500 + nla_total_size(4) /* RTA_PREFSRC */
501 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
502 unsigned int nhs = fib_info_num_path(fi);
503
504 /* space for nested metrics */
505 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
506
507 if (fi->nh)
508 payload += nla_total_size(4); /* RTA_NH_ID */
509
510 if (nhs) {
511 size_t nh_encapsize = 0;
512 /* Also handles the special case nhs == 1 */
513
514 /* each nexthop is packed in an attribute */
515 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
516 unsigned int i;
517
518 /* may contain flow and gateway attribute */
519 nhsize += 2 * nla_total_size(4);
520
521 /* grab encap info */
522 for (i = 0; i < fib_info_num_path(fi); i++) {
523 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
524
525 if (nhc->nhc_lwtstate) {
526 /* RTA_ENCAP_TYPE */
527 nh_encapsize += lwtunnel_get_encap_size(
528 nhc->nhc_lwtstate);
529 /* RTA_ENCAP */
530 nh_encapsize += nla_total_size(2);
531 }
532 }
533
534 /* all nexthops are packed in a nested attribute */
535 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
536
537 }
538
539 return payload;
540 }
541
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)542 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
543 int dst_len, u32 tb_id, const struct nl_info *info,
544 unsigned int nlm_flags)
545 {
546 struct fib_rt_info fri;
547 struct sk_buff *skb;
548 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
549 int err = -ENOBUFS;
550
551 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
552 if (!skb)
553 goto errout;
554
555 fri.fi = fa->fa_info;
556 fri.tb_id = tb_id;
557 fri.dst = key;
558 fri.dst_len = dst_len;
559 fri.dscp = fa->fa_dscp;
560 fri.type = fa->fa_type;
561 fri.offload = READ_ONCE(fa->offload);
562 fri.trap = READ_ONCE(fa->trap);
563 fri.offload_failed = READ_ONCE(fa->offload_failed);
564 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
565 if (err < 0) {
566 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
567 WARN_ON(err == -EMSGSIZE);
568 kfree_skb(skb);
569 goto errout;
570 }
571 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
572 info->nlh, GFP_KERNEL);
573 return;
574 errout:
575 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
576 }
577
fib_detect_death(struct fib_info * fi,int order,struct fib_info ** last_resort,int * last_idx,int dflt)578 static int fib_detect_death(struct fib_info *fi, int order,
579 struct fib_info **last_resort, int *last_idx,
580 int dflt)
581 {
582 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
583 struct neighbour *n;
584 int state = NUD_NONE;
585
586 if (likely(nhc->nhc_gw_family == AF_INET))
587 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
588 else if (nhc->nhc_gw_family == AF_INET6)
589 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
590 nhc->nhc_dev);
591 else
592 n = NULL;
593
594 if (n) {
595 state = READ_ONCE(n->nud_state);
596 neigh_release(n);
597 } else {
598 return 0;
599 }
600 if (state == NUD_REACHABLE)
601 return 0;
602 if ((state & NUD_VALID) && order != dflt)
603 return 0;
604 if ((state & NUD_VALID) ||
605 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
606 *last_resort = fi;
607 *last_idx = order;
608 }
609 return 1;
610 }
611
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)612 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
613 struct nlattr *encap, u16 encap_type,
614 void *cfg, gfp_t gfp_flags,
615 struct netlink_ext_ack *extack)
616 {
617 int err;
618
619 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
620 gfp_flags);
621 if (!nhc->nhc_pcpu_rth_output)
622 return -ENOMEM;
623
624 if (encap) {
625 struct lwtunnel_state *lwtstate;
626
627 err = lwtunnel_build_state(net, encap_type, encap,
628 nhc->nhc_family, cfg, &lwtstate,
629 extack);
630 if (err)
631 goto lwt_failure;
632
633 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
634 }
635
636 return 0;
637
638 lwt_failure:
639 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
640 nhc->nhc_pcpu_rth_output = NULL;
641 return err;
642 }
643 EXPORT_SYMBOL_GPL(fib_nh_common_init);
644
fib_nh_init(struct net * net,struct fib_nh * nh,struct fib_config * cfg,int nh_weight,struct netlink_ext_ack * extack)645 int fib_nh_init(struct net *net, struct fib_nh *nh,
646 struct fib_config *cfg, int nh_weight,
647 struct netlink_ext_ack *extack)
648 {
649 int err;
650
651 nh->fib_nh_family = AF_INET;
652
653 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
654 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
655 if (err)
656 return err;
657
658 nh->fib_nh_oif = cfg->fc_oif;
659 nh->fib_nh_gw_family = cfg->fc_gw_family;
660 if (cfg->fc_gw_family == AF_INET)
661 nh->fib_nh_gw4 = cfg->fc_gw4;
662 else if (cfg->fc_gw_family == AF_INET6)
663 nh->fib_nh_gw6 = cfg->fc_gw6;
664
665 nh->fib_nh_flags = cfg->fc_flags;
666
667 #ifdef CONFIG_IP_ROUTE_CLASSID
668 nh->nh_tclassid = cfg->fc_flow;
669 if (nh->nh_tclassid)
670 atomic_inc(&net->ipv4.fib_num_tclassid_users);
671 #endif
672 #ifdef CONFIG_IP_ROUTE_MULTIPATH
673 nh->fib_nh_weight = nh_weight;
674 #endif
675 return 0;
676 }
677
678 #ifdef CONFIG_IP_ROUTE_MULTIPATH
679
fib_count_nexthops(struct rtnexthop * rtnh,int remaining,struct netlink_ext_ack * extack)680 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
681 struct netlink_ext_ack *extack)
682 {
683 int nhs = 0;
684
685 while (rtnh_ok(rtnh, remaining)) {
686 nhs++;
687 rtnh = rtnh_next(rtnh, &remaining);
688 }
689
690 /* leftover implies invalid nexthop configuration, discard it */
691 if (remaining > 0) {
692 NL_SET_ERR_MSG(extack,
693 "Invalid nexthop configuration - extra data after nexthops");
694 nhs = 0;
695 }
696
697 return nhs;
698 }
699
fib_gw_from_attr(__be32 * gw,struct nlattr * nla,struct netlink_ext_ack * extack)700 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
701 struct netlink_ext_ack *extack)
702 {
703 if (nla_len(nla) < sizeof(*gw)) {
704 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
705 return -EINVAL;
706 }
707
708 *gw = nla_get_in_addr(nla);
709
710 return 0;
711 }
712
713 /* 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)714 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
715 int remaining, struct fib_config *cfg,
716 struct netlink_ext_ack *extack)
717 {
718 struct net *net = fi->fib_net;
719 struct fib_config fib_cfg;
720 struct fib_nh *nh;
721 int ret;
722
723 change_nexthops(fi) {
724 int attrlen;
725
726 memset(&fib_cfg, 0, sizeof(fib_cfg));
727
728 if (!rtnh_ok(rtnh, remaining)) {
729 NL_SET_ERR_MSG(extack,
730 "Invalid nexthop configuration - extra data after nexthop");
731 return -EINVAL;
732 }
733
734 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
735 NL_SET_ERR_MSG(extack,
736 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
737 return -EINVAL;
738 }
739
740 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
741 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
742
743 attrlen = rtnh_attrlen(rtnh);
744 if (attrlen > 0) {
745 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
746
747 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
748 nlav = nla_find(attrs, attrlen, RTA_VIA);
749 if (nla && nlav) {
750 NL_SET_ERR_MSG(extack,
751 "Nexthop configuration can not contain both GATEWAY and VIA");
752 return -EINVAL;
753 }
754 if (nla) {
755 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
756 extack);
757 if (ret)
758 goto errout;
759
760 if (fib_cfg.fc_gw4)
761 fib_cfg.fc_gw_family = AF_INET;
762 } else if (nlav) {
763 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
764 if (ret)
765 goto errout;
766 }
767
768 nla = nla_find(attrs, attrlen, RTA_FLOW);
769 if (nla) {
770 if (nla_len(nla) < sizeof(u32)) {
771 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
772 return -EINVAL;
773 }
774 fib_cfg.fc_flow = nla_get_u32(nla);
775 }
776
777 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
778 /* RTA_ENCAP_TYPE length checked in
779 * lwtunnel_valid_encap_type_attr
780 */
781 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
782 if (nla)
783 fib_cfg.fc_encap_type = nla_get_u16(nla);
784 }
785
786 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
787 rtnh->rtnh_hops + 1, extack);
788 if (ret)
789 goto errout;
790
791 rtnh = rtnh_next(rtnh, &remaining);
792 } endfor_nexthops(fi);
793
794 ret = -EINVAL;
795 nh = fib_info_nh(fi, 0);
796 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
797 NL_SET_ERR_MSG(extack,
798 "Nexthop device index does not match RTA_OIF");
799 goto errout;
800 }
801 if (cfg->fc_gw_family) {
802 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
803 (cfg->fc_gw_family == AF_INET &&
804 nh->fib_nh_gw4 != cfg->fc_gw4) ||
805 (cfg->fc_gw_family == AF_INET6 &&
806 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
807 NL_SET_ERR_MSG(extack,
808 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
809 goto errout;
810 }
811 }
812 #ifdef CONFIG_IP_ROUTE_CLASSID
813 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
814 NL_SET_ERR_MSG(extack,
815 "Nexthop class id does not match RTA_FLOW");
816 goto errout;
817 }
818 #endif
819 ret = 0;
820 errout:
821 return ret;
822 }
823
824 /* only called when fib_nh is integrated into fib_info */
fib_rebalance(struct fib_info * fi)825 static void fib_rebalance(struct fib_info *fi)
826 {
827 int total;
828 int w;
829
830 if (fib_info_num_path(fi) < 2)
831 return;
832
833 total = 0;
834 for_nexthops(fi) {
835 if (nh->fib_nh_flags & RTNH_F_DEAD)
836 continue;
837
838 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
839 nh->fib_nh_flags & RTNH_F_LINKDOWN)
840 continue;
841
842 total += nh->fib_nh_weight;
843 } endfor_nexthops(fi);
844
845 w = 0;
846 change_nexthops(fi) {
847 int upper_bound;
848
849 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
850 upper_bound = -1;
851 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
852 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
853 upper_bound = -1;
854 } else {
855 w += nexthop_nh->fib_nh_weight;
856 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
857 total) - 1;
858 }
859
860 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
861 } endfor_nexthops(fi);
862 }
863 #else /* CONFIG_IP_ROUTE_MULTIPATH */
864
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)865 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
866 int remaining, struct fib_config *cfg,
867 struct netlink_ext_ack *extack)
868 {
869 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
870
871 return -EINVAL;
872 }
873
874 #define fib_rebalance(fi) do { } while (0)
875
876 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
877
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)878 static int fib_encap_match(struct net *net, u16 encap_type,
879 struct nlattr *encap,
880 const struct fib_nh *nh,
881 const struct fib_config *cfg,
882 struct netlink_ext_ack *extack)
883 {
884 struct lwtunnel_state *lwtstate;
885 int ret, result = 0;
886
887 if (encap_type == LWTUNNEL_ENCAP_NONE)
888 return 0;
889
890 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
891 cfg, &lwtstate, extack);
892 if (!ret) {
893 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
894 lwtstate_free(lwtstate);
895 }
896
897 return result;
898 }
899
fib_nh_match(struct net * net,struct fib_config * cfg,struct fib_info * fi,struct netlink_ext_ack * extack)900 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
901 struct netlink_ext_ack *extack)
902 {
903 #ifdef CONFIG_IP_ROUTE_MULTIPATH
904 struct rtnexthop *rtnh;
905 int remaining;
906 #endif
907
908 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
909 return 1;
910
911 if (cfg->fc_nh_id) {
912 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
913 return 0;
914 return 1;
915 }
916
917 if (fi->nh) {
918 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
919 return 1;
920 return 0;
921 }
922
923 if (cfg->fc_oif || cfg->fc_gw_family) {
924 struct fib_nh *nh;
925
926 nh = fib_info_nh(fi, 0);
927 if (cfg->fc_encap) {
928 if (fib_encap_match(net, cfg->fc_encap_type,
929 cfg->fc_encap, nh, cfg, extack))
930 return 1;
931 }
932 #ifdef CONFIG_IP_ROUTE_CLASSID
933 if (cfg->fc_flow &&
934 cfg->fc_flow != nh->nh_tclassid)
935 return 1;
936 #endif
937 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
938 (cfg->fc_gw_family &&
939 cfg->fc_gw_family != nh->fib_nh_gw_family))
940 return 1;
941
942 if (cfg->fc_gw_family == AF_INET &&
943 cfg->fc_gw4 != nh->fib_nh_gw4)
944 return 1;
945
946 if (cfg->fc_gw_family == AF_INET6 &&
947 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
948 return 1;
949
950 return 0;
951 }
952
953 #ifdef CONFIG_IP_ROUTE_MULTIPATH
954 if (!cfg->fc_mp)
955 return 0;
956
957 rtnh = cfg->fc_mp;
958 remaining = cfg->fc_mp_len;
959
960 for_nexthops(fi) {
961 int attrlen;
962
963 if (!rtnh_ok(rtnh, remaining))
964 return -EINVAL;
965
966 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
967 return 1;
968
969 attrlen = rtnh_attrlen(rtnh);
970 if (attrlen > 0) {
971 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
972 int err;
973
974 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
975 nlav = nla_find(attrs, attrlen, RTA_VIA);
976 if (nla && nlav) {
977 NL_SET_ERR_MSG(extack,
978 "Nexthop configuration can not contain both GATEWAY and VIA");
979 return -EINVAL;
980 }
981
982 if (nla) {
983 __be32 gw;
984
985 err = fib_gw_from_attr(&gw, nla, extack);
986 if (err)
987 return err;
988
989 if (nh->fib_nh_gw_family != AF_INET ||
990 gw != nh->fib_nh_gw4)
991 return 1;
992 } else if (nlav) {
993 struct fib_config cfg2;
994
995 err = fib_gw_from_via(&cfg2, nlav, extack);
996 if (err)
997 return err;
998
999 switch (nh->fib_nh_gw_family) {
1000 case AF_INET:
1001 if (cfg2.fc_gw_family != AF_INET ||
1002 cfg2.fc_gw4 != nh->fib_nh_gw4)
1003 return 1;
1004 break;
1005 case AF_INET6:
1006 if (cfg2.fc_gw_family != AF_INET6 ||
1007 ipv6_addr_cmp(&cfg2.fc_gw6,
1008 &nh->fib_nh_gw6))
1009 return 1;
1010 break;
1011 }
1012 }
1013
1014 #ifdef CONFIG_IP_ROUTE_CLASSID
1015 nla = nla_find(attrs, attrlen, RTA_FLOW);
1016 if (nla) {
1017 if (nla_len(nla) < sizeof(u32)) {
1018 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
1019 return -EINVAL;
1020 }
1021 if (nla_get_u32(nla) != nh->nh_tclassid)
1022 return 1;
1023 }
1024 #endif
1025 }
1026
1027 rtnh = rtnh_next(rtnh, &remaining);
1028 } endfor_nexthops(fi);
1029 #endif
1030 return 0;
1031 }
1032
fib_metrics_match(struct fib_config * cfg,struct fib_info * fi)1033 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1034 {
1035 struct nlattr *nla;
1036 int remaining;
1037
1038 if (!cfg->fc_mx)
1039 return true;
1040
1041 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1042 int type = nla_type(nla);
1043 u32 fi_val, val;
1044
1045 if (!type)
1046 continue;
1047 if (type > RTAX_MAX)
1048 return false;
1049
1050 type = array_index_nospec(type, RTAX_MAX + 1);
1051 if (type == RTAX_CC_ALGO) {
1052 char tmp[TCP_CA_NAME_MAX];
1053 bool ecn_ca = false;
1054
1055 nla_strscpy(tmp, nla, sizeof(tmp));
1056 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
1057 } else {
1058 if (nla_len(nla) != sizeof(u32))
1059 return false;
1060 val = nla_get_u32(nla);
1061 }
1062
1063 fi_val = fi->fib_metrics->metrics[type - 1];
1064 if (type == RTAX_FEATURES)
1065 fi_val &= ~DST_FEATURE_ECN_CA;
1066
1067 if (fi_val != val)
1068 return false;
1069 }
1070
1071 return true;
1072 }
1073
fib_check_nh_v6_gw(struct net * net,struct fib_nh * nh,u32 table,struct netlink_ext_ack * extack)1074 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1075 u32 table, struct netlink_ext_ack *extack)
1076 {
1077 struct fib6_config cfg = {
1078 .fc_table = table,
1079 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1080 .fc_ifindex = nh->fib_nh_oif,
1081 .fc_gateway = nh->fib_nh_gw6,
1082 };
1083 struct fib6_nh fib6_nh = {};
1084 int err;
1085
1086 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1087 if (!err) {
1088 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1089 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1090 GFP_KERNEL);
1091 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1092 nh->fib_nh_scope = RT_SCOPE_LINK;
1093
1094 ipv6_stub->fib6_nh_release(&fib6_nh);
1095 }
1096
1097 return err;
1098 }
1099
1100 /*
1101 * Picture
1102 * -------
1103 *
1104 * Semantics of nexthop is very messy by historical reasons.
1105 * We have to take into account, that:
1106 * a) gateway can be actually local interface address,
1107 * so that gatewayed route is direct.
1108 * b) gateway must be on-link address, possibly
1109 * described not by an ifaddr, but also by a direct route.
1110 * c) If both gateway and interface are specified, they should not
1111 * contradict.
1112 * d) If we use tunnel routes, gateway could be not on-link.
1113 *
1114 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1115 * results in pretty ugly and hairy code with obscure logic.
1116 *
1117 * I chose to generalized it instead, so that the size
1118 * of code does not increase practically, but it becomes
1119 * much more general.
1120 * Every prefix is assigned a "scope" value: "host" is local address,
1121 * "link" is direct route,
1122 * [ ... "site" ... "interior" ... ]
1123 * and "universe" is true gateway route with global meaning.
1124 *
1125 * Every prefix refers to a set of "nexthop"s (gw, oif),
1126 * where gw must have narrower scope. This recursion stops
1127 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1128 * which means that gw is forced to be on link.
1129 *
1130 * Code is still hairy, but now it is apparently logically
1131 * consistent and very flexible. F.e. as by-product it allows
1132 * to co-exists in peace independent exterior and interior
1133 * routing processes.
1134 *
1135 * Normally it looks as following.
1136 *
1137 * {universe prefix} -> (gw, oif) [scope link]
1138 * |
1139 * |-> {link prefix} -> (gw, oif) [scope local]
1140 * |
1141 * |-> {local prefix} (terminal node)
1142 */
fib_check_nh_v4_gw(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1143 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1144 u8 scope, struct netlink_ext_ack *extack)
1145 {
1146 struct net_device *dev;
1147 struct fib_result res;
1148 int err = 0;
1149
1150 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1151 unsigned int addr_type;
1152
1153 if (scope >= RT_SCOPE_LINK) {
1154 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1155 return -EINVAL;
1156 }
1157 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1158 if (!dev) {
1159 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1160 return -ENODEV;
1161 }
1162 if (!(dev->flags & IFF_UP)) {
1163 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1164 return -ENETDOWN;
1165 }
1166 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1167 if (addr_type != RTN_UNICAST) {
1168 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1169 return -EINVAL;
1170 }
1171 if (!netif_carrier_ok(dev))
1172 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1173 nh->fib_nh_dev = dev;
1174 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1175 nh->fib_nh_scope = RT_SCOPE_LINK;
1176 return 0;
1177 }
1178 rcu_read_lock();
1179 {
1180 struct fib_table *tbl = NULL;
1181 struct flowi4 fl4 = {
1182 .daddr = nh->fib_nh_gw4,
1183 .flowi4_scope = scope + 1,
1184 .flowi4_oif = nh->fib_nh_oif,
1185 .flowi4_iif = LOOPBACK_IFINDEX,
1186 };
1187
1188 /* It is not necessary, but requires a bit of thinking */
1189 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1190 fl4.flowi4_scope = RT_SCOPE_LINK;
1191
1192 if (table && table != RT_TABLE_MAIN)
1193 tbl = fib_get_table(net, table);
1194
1195 if (tbl)
1196 err = fib_table_lookup(tbl, &fl4, &res,
1197 FIB_LOOKUP_IGNORE_LINKSTATE |
1198 FIB_LOOKUP_NOREF);
1199
1200 /* on error or if no table given do full lookup. This
1201 * is needed for example when nexthops are in the local
1202 * table rather than the given table
1203 */
1204 if (!tbl || err) {
1205 err = fib_lookup(net, &fl4, &res,
1206 FIB_LOOKUP_IGNORE_LINKSTATE);
1207 }
1208
1209 if (err) {
1210 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1211 goto out;
1212 }
1213 }
1214
1215 err = -EINVAL;
1216 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1217 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1218 goto out;
1219 }
1220 nh->fib_nh_scope = res.scope;
1221 nh->fib_nh_oif = FIB_RES_OIF(res);
1222 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1223 if (!dev) {
1224 NL_SET_ERR_MSG(extack,
1225 "No egress device for nexthop gateway");
1226 goto out;
1227 }
1228 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1229 if (!netif_carrier_ok(dev))
1230 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1231 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1232 out:
1233 rcu_read_unlock();
1234 return err;
1235 }
1236
fib_check_nh_nongw(struct net * net,struct fib_nh * nh,struct netlink_ext_ack * extack)1237 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1238 struct netlink_ext_ack *extack)
1239 {
1240 struct in_device *in_dev;
1241 int err;
1242
1243 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1244 NL_SET_ERR_MSG(extack,
1245 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1246 return -EINVAL;
1247 }
1248
1249 rcu_read_lock();
1250
1251 err = -ENODEV;
1252 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1253 if (!in_dev)
1254 goto out;
1255 err = -ENETDOWN;
1256 if (!(in_dev->dev->flags & IFF_UP)) {
1257 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1258 goto out;
1259 }
1260
1261 nh->fib_nh_dev = in_dev->dev;
1262 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1263 nh->fib_nh_scope = RT_SCOPE_HOST;
1264 if (!netif_carrier_ok(nh->fib_nh_dev))
1265 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1266 err = 0;
1267 out:
1268 rcu_read_unlock();
1269 return err;
1270 }
1271
fib_check_nh(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1272 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1273 struct netlink_ext_ack *extack)
1274 {
1275 int err;
1276
1277 if (nh->fib_nh_gw_family == AF_INET)
1278 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1279 else if (nh->fib_nh_gw_family == AF_INET6)
1280 err = fib_check_nh_v6_gw(net, nh, table, extack);
1281 else
1282 err = fib_check_nh_nongw(net, nh, extack);
1283
1284 return err;
1285 }
1286
fib_info_update_nhc_saddr(struct net * net,struct fib_nh_common * nhc,unsigned char scope)1287 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1288 unsigned char scope)
1289 {
1290 struct fib_nh *nh;
1291 __be32 saddr;
1292
1293 if (nhc->nhc_family != AF_INET)
1294 return inet_select_addr(nhc->nhc_dev, 0, scope);
1295
1296 nh = container_of(nhc, struct fib_nh, nh_common);
1297 saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1298
1299 WRITE_ONCE(nh->nh_saddr, saddr);
1300 WRITE_ONCE(nh->nh_saddr_genid, atomic_read(&net->ipv4.dev_addr_genid));
1301
1302 return saddr;
1303 }
1304
fib_result_prefsrc(struct net * net,struct fib_result * res)1305 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1306 {
1307 struct fib_nh_common *nhc = res->nhc;
1308
1309 if (res->fi->fib_prefsrc)
1310 return res->fi->fib_prefsrc;
1311
1312 if (nhc->nhc_family == AF_INET) {
1313 struct fib_nh *nh;
1314
1315 nh = container_of(nhc, struct fib_nh, nh_common);
1316 if (READ_ONCE(nh->nh_saddr_genid) ==
1317 atomic_read(&net->ipv4.dev_addr_genid))
1318 return READ_ONCE(nh->nh_saddr);
1319 }
1320
1321 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1322 }
1323
fib_valid_prefsrc(struct fib_config * cfg,__be32 fib_prefsrc)1324 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1325 {
1326 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1327 fib_prefsrc != cfg->fc_dst) {
1328 u32 tb_id = cfg->fc_table;
1329 int rc;
1330
1331 if (tb_id == RT_TABLE_MAIN)
1332 tb_id = RT_TABLE_LOCAL;
1333
1334 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1335 fib_prefsrc, tb_id);
1336
1337 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1338 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1339 fib_prefsrc, RT_TABLE_LOCAL);
1340 }
1341
1342 if (rc != RTN_LOCAL)
1343 return false;
1344 }
1345 return true;
1346 }
1347
fib_create_info(struct fib_config * cfg,struct netlink_ext_ack * extack)1348 struct fib_info *fib_create_info(struct fib_config *cfg,
1349 struct netlink_ext_ack *extack)
1350 {
1351 int err;
1352 struct fib_info *fi = NULL;
1353 struct nexthop *nh = NULL;
1354 struct fib_info *ofi;
1355 int nhs = 1;
1356 struct net *net = cfg->fc_nlinfo.nl_net;
1357
1358 ASSERT_RTNL();
1359 if (cfg->fc_type > RTN_MAX)
1360 goto err_inval;
1361
1362 /* Fast check to catch the most weird cases */
1363 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1364 NL_SET_ERR_MSG(extack, "Invalid scope");
1365 goto err_inval;
1366 }
1367
1368 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1369 NL_SET_ERR_MSG(extack,
1370 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1371 goto err_inval;
1372 }
1373
1374 if (cfg->fc_nh_id) {
1375 if (!cfg->fc_mx) {
1376 fi = fib_find_info_nh(net, cfg);
1377 if (fi) {
1378 refcount_inc(&fi->fib_treeref);
1379 return fi;
1380 }
1381 }
1382
1383 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1384 if (!nh) {
1385 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1386 goto err_inval;
1387 }
1388 nhs = 0;
1389 }
1390
1391 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1392 if (cfg->fc_mp) {
1393 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1394 if (nhs == 0)
1395 goto err_inval;
1396 }
1397 #endif
1398
1399 fib_info_hash_grow(net);
1400
1401 fi = kzalloc_flex(*fi, fib_nh, nhs);
1402 if (!fi) {
1403 err = -ENOBUFS;
1404 goto failure;
1405 }
1406
1407 fi->fib_metrics = ip_fib_metrics_init(cfg->fc_mx, cfg->fc_mx_len, extack);
1408 if (IS_ERR(fi->fib_metrics)) {
1409 err = PTR_ERR(fi->fib_metrics);
1410 kfree(fi);
1411 return ERR_PTR(err);
1412 }
1413
1414 fi->fib_net = net;
1415 fi->fib_protocol = cfg->fc_protocol;
1416 fi->fib_scope = cfg->fc_scope;
1417 fi->fib_flags = cfg->fc_flags;
1418 fi->fib_priority = cfg->fc_priority;
1419 fi->fib_prefsrc = cfg->fc_prefsrc;
1420 fi->fib_type = cfg->fc_type;
1421 fi->fib_tb_id = cfg->fc_table;
1422
1423 fi->fib_nhs = nhs;
1424 if (nh) {
1425 if (!nexthop_get(nh)) {
1426 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1427 err = -EINVAL;
1428 } else {
1429 err = 0;
1430 fi->nh = nh;
1431 }
1432 } else {
1433 change_nexthops(fi) {
1434 nexthop_nh->nh_parent = fi;
1435 } endfor_nexthops(fi)
1436
1437 if (cfg->fc_mp)
1438 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1439 extack);
1440 else
1441 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1442 }
1443
1444 if (err != 0)
1445 goto failure;
1446
1447 if (fib_props[cfg->fc_type].error) {
1448 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1449 NL_SET_ERR_MSG(extack,
1450 "Gateway, device and multipath can not be specified for this route type");
1451 goto err_inval;
1452 }
1453 goto link_it;
1454 } else {
1455 switch (cfg->fc_type) {
1456 case RTN_UNICAST:
1457 case RTN_LOCAL:
1458 case RTN_BROADCAST:
1459 case RTN_ANYCAST:
1460 case RTN_MULTICAST:
1461 break;
1462 default:
1463 NL_SET_ERR_MSG(extack, "Invalid route type");
1464 goto err_inval;
1465 }
1466 }
1467
1468 if (cfg->fc_scope > RT_SCOPE_HOST) {
1469 NL_SET_ERR_MSG(extack, "Invalid scope");
1470 goto err_inval;
1471 }
1472
1473 if (fi->nh) {
1474 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1475 if (err)
1476 goto failure;
1477 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1478 struct fib_nh *nh = fi->fib_nh;
1479
1480 /* Local address is added. */
1481 if (nhs != 1) {
1482 NL_SET_ERR_MSG(extack,
1483 "Route with host scope can not have multiple nexthops");
1484 goto err_inval;
1485 }
1486 if (nh->fib_nh_gw_family) {
1487 NL_SET_ERR_MSG(extack,
1488 "Route with host scope can not have a gateway");
1489 goto err_inval;
1490 }
1491 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1492 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1493 err = -ENODEV;
1494 if (!nh->fib_nh_dev)
1495 goto failure;
1496 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1497 GFP_KERNEL);
1498 } else {
1499 int linkdown = 0;
1500
1501 change_nexthops(fi) {
1502 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1503 cfg->fc_table, cfg->fc_scope,
1504 extack);
1505 if (err != 0)
1506 goto failure;
1507 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1508 linkdown++;
1509 } endfor_nexthops(fi)
1510 if (linkdown == fi->fib_nhs)
1511 fi->fib_flags |= RTNH_F_LINKDOWN;
1512 }
1513
1514 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1515 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1516 goto err_inval;
1517 }
1518
1519 if (!fi->nh) {
1520 change_nexthops(fi) {
1521 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1522 fi->fib_scope);
1523 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1524 fi->fib_nh_is_v6 = true;
1525 } endfor_nexthops(fi)
1526
1527 fib_rebalance(fi);
1528 }
1529
1530 link_it:
1531 ofi = fib_find_info(fi);
1532 if (ofi) {
1533 /* fib_table_lookup() should not see @fi yet. */
1534 fi->fib_dead = 1;
1535 free_fib_info(fi);
1536 refcount_inc(&ofi->fib_treeref);
1537 return ofi;
1538 }
1539
1540 refcount_set(&fi->fib_treeref, 1);
1541 refcount_set(&fi->fib_clntref, 1);
1542
1543 net->ipv4.fib_info_cnt++;
1544 hlist_add_head(&fi->fib_hash, fib_info_hash_bucket(fi));
1545
1546 if (fi->fib_prefsrc) {
1547 struct hlist_head *head;
1548
1549 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc);
1550 hlist_add_head(&fi->fib_lhash, head);
1551 }
1552 if (fi->nh) {
1553 list_add(&fi->nh_list, &nh->fi_list);
1554 } else {
1555 change_nexthops(fi) {
1556 struct hlist_head *head;
1557
1558 if (!nexthop_nh->fib_nh_dev)
1559 continue;
1560 head = fib_nh_head(nexthop_nh->fib_nh_dev);
1561 hlist_add_head_rcu(&nexthop_nh->nh_hash, head);
1562 } endfor_nexthops(fi)
1563 }
1564 return fi;
1565
1566 err_inval:
1567 err = -EINVAL;
1568
1569 failure:
1570 if (fi) {
1571 /* fib_table_lookup() should not see @fi yet. */
1572 fi->fib_dead = 1;
1573 free_fib_info(fi);
1574 }
1575
1576 return ERR_PTR(err);
1577 }
1578
fib_nexthop_info(struct sk_buff * skb,const struct fib_nh_common * nhc,u8 rt_family,unsigned char * flags,bool skip_oif)1579 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1580 u8 rt_family, unsigned char *flags, bool skip_oif)
1581 {
1582 if (nhc->nhc_flags & RTNH_F_DEAD)
1583 *flags |= RTNH_F_DEAD;
1584
1585 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1586 *flags |= RTNH_F_LINKDOWN;
1587
1588 rcu_read_lock();
1589 switch (nhc->nhc_family) {
1590 case AF_INET:
1591 if (ip_ignore_linkdown(nhc->nhc_dev))
1592 *flags |= RTNH_F_DEAD;
1593 break;
1594 case AF_INET6:
1595 if (ip6_ignore_linkdown(nhc->nhc_dev))
1596 *flags |= RTNH_F_DEAD;
1597 break;
1598 }
1599 rcu_read_unlock();
1600 }
1601
1602 switch (nhc->nhc_gw_family) {
1603 case AF_INET:
1604 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1605 goto nla_put_failure;
1606 break;
1607 case AF_INET6:
1608 /* if gateway family does not match nexthop family
1609 * gateway is encoded as RTA_VIA
1610 */
1611 if (rt_family != nhc->nhc_gw_family) {
1612 int alen = sizeof(struct in6_addr);
1613 struct nlattr *nla;
1614 struct rtvia *via;
1615
1616 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1617 if (!nla)
1618 goto nla_put_failure;
1619
1620 via = nla_data(nla);
1621 via->rtvia_family = AF_INET6;
1622 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1623 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1624 &nhc->nhc_gw.ipv6) < 0) {
1625 goto nla_put_failure;
1626 }
1627 break;
1628 }
1629
1630 *flags |= (nhc->nhc_flags &
1631 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1632
1633 if (!skip_oif && nhc->nhc_dev &&
1634 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1635 goto nla_put_failure;
1636
1637 if (lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1638 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1639 goto nla_put_failure;
1640
1641 return 0;
1642
1643 nla_put_failure:
1644 return -EMSGSIZE;
1645 }
1646 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1647
1648 #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)1649 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1650 int nh_weight, u8 rt_family, u32 nh_tclassid)
1651 {
1652 const struct net_device *dev = nhc->nhc_dev;
1653 struct rtnexthop *rtnh;
1654 unsigned char flags = 0;
1655
1656 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1657 if (!rtnh)
1658 goto nla_put_failure;
1659
1660 rtnh->rtnh_hops = nh_weight - 1;
1661 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1662
1663 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1664 goto nla_put_failure;
1665
1666 rtnh->rtnh_flags = flags;
1667
1668 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1669 goto nla_put_failure;
1670
1671 /* length of rtnetlink header + attributes */
1672 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1673
1674 return 0;
1675
1676 nla_put_failure:
1677 return -EMSGSIZE;
1678 }
1679 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1680 #endif
1681
1682 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1683 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1684 {
1685 struct nlattr *mp;
1686
1687 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1688 if (!mp)
1689 goto nla_put_failure;
1690
1691 if (unlikely(fi->nh)) {
1692 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1693 goto nla_put_failure;
1694 goto mp_end;
1695 }
1696
1697 for_nexthops(fi) {
1698 u32 nh_tclassid = 0;
1699 #ifdef CONFIG_IP_ROUTE_CLASSID
1700 nh_tclassid = nh->nh_tclassid;
1701 #endif
1702 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1703 AF_INET, nh_tclassid) < 0)
1704 goto nla_put_failure;
1705 } endfor_nexthops(fi);
1706
1707 mp_end:
1708 nla_nest_end(skb, mp);
1709
1710 return 0;
1711
1712 nla_put_failure:
1713 return -EMSGSIZE;
1714 }
1715 #else
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1716 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1717 {
1718 return 0;
1719 }
1720 #endif
1721
fib_dump_info(struct sk_buff * skb,u32 portid,u32 seq,int event,const struct fib_rt_info * fri,unsigned int flags)1722 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1723 const struct fib_rt_info *fri, unsigned int flags)
1724 {
1725 unsigned int nhs = fib_info_num_path(fri->fi);
1726 struct fib_info *fi = fri->fi;
1727 u32 tb_id = fri->tb_id;
1728 struct nlmsghdr *nlh;
1729 struct rtmsg *rtm;
1730
1731 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1732 if (!nlh)
1733 return -EMSGSIZE;
1734
1735 rtm = nlmsg_data(nlh);
1736 rtm->rtm_family = AF_INET;
1737 rtm->rtm_dst_len = fri->dst_len;
1738 rtm->rtm_src_len = 0;
1739 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp);
1740 if (tb_id < 256)
1741 rtm->rtm_table = tb_id;
1742 else
1743 rtm->rtm_table = RT_TABLE_COMPAT;
1744 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1745 goto nla_put_failure;
1746 rtm->rtm_type = fri->type;
1747 rtm->rtm_flags = fi->fib_flags;
1748 rtm->rtm_scope = fi->fib_scope;
1749 rtm->rtm_protocol = fi->fib_protocol;
1750
1751 if (rtm->rtm_dst_len &&
1752 nla_put_in_addr(skb, RTA_DST, fri->dst))
1753 goto nla_put_failure;
1754 if (fi->fib_priority &&
1755 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1756 goto nla_put_failure;
1757 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1758 goto nla_put_failure;
1759
1760 if (fi->fib_prefsrc &&
1761 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1762 goto nla_put_failure;
1763
1764 if (fi->nh) {
1765 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1766 goto nla_put_failure;
1767 if (nexthop_is_blackhole(fi->nh))
1768 rtm->rtm_type = RTN_BLACKHOLE;
1769 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
1770 goto offload;
1771 }
1772
1773 if (nhs == 1) {
1774 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1775 unsigned char flags = 0;
1776
1777 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1778 goto nla_put_failure;
1779
1780 rtm->rtm_flags = flags;
1781 #ifdef CONFIG_IP_ROUTE_CLASSID
1782 if (nhc->nhc_family == AF_INET) {
1783 struct fib_nh *nh;
1784
1785 nh = container_of(nhc, struct fib_nh, nh_common);
1786 if (nh->nh_tclassid &&
1787 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1788 goto nla_put_failure;
1789 }
1790 #endif
1791 } else {
1792 if (fib_add_multipath(skb, fi) < 0)
1793 goto nla_put_failure;
1794 }
1795
1796 offload:
1797 if (fri->offload)
1798 rtm->rtm_flags |= RTM_F_OFFLOAD;
1799 if (fri->trap)
1800 rtm->rtm_flags |= RTM_F_TRAP;
1801 if (fri->offload_failed)
1802 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1803
1804 nlmsg_end(skb, nlh);
1805 return 0;
1806
1807 nla_put_failure:
1808 nlmsg_cancel(skb, nlh);
1809 return -EMSGSIZE;
1810 }
1811
1812 /*
1813 * Update FIB if:
1814 * - local address disappeared -> we must delete all the entries
1815 * referring to it.
1816 * - device went down -> we must shutdown all nexthops going via it.
1817 */
fib_sync_down_addr(struct net_device * dev,__be32 local)1818 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1819 {
1820 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1821 struct net *net = dev_net(dev);
1822 struct hlist_head *head;
1823 struct fib_info *fi;
1824 int ret = 0;
1825
1826 if (!local)
1827 return 0;
1828
1829 head = fib_info_laddrhash_bucket(net, local);
1830 hlist_for_each_entry(fi, head, fib_lhash) {
1831 if (!net_eq(fi->fib_net, net) ||
1832 fi->fib_tb_id != tb_id)
1833 continue;
1834 if (fi->fib_prefsrc == local) {
1835 fi->fib_flags |= RTNH_F_DEAD;
1836 fi->pfsrc_removed = true;
1837 ret++;
1838 }
1839 }
1840 return ret;
1841 }
1842
call_fib_nh_notifiers(struct fib_nh * nh,enum fib_event_type event_type)1843 static int call_fib_nh_notifiers(struct fib_nh *nh,
1844 enum fib_event_type event_type)
1845 {
1846 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1847 struct fib_nh_notifier_info info = {
1848 .fib_nh = nh,
1849 };
1850
1851 switch (event_type) {
1852 case FIB_EVENT_NH_ADD:
1853 if (nh->fib_nh_flags & RTNH_F_DEAD)
1854 break;
1855 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1856 break;
1857 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1858 &info.info);
1859 case FIB_EVENT_NH_DEL:
1860 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1861 (nh->fib_nh_flags & RTNH_F_DEAD))
1862 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1863 event_type, &info.info);
1864 break;
1865 default:
1866 break;
1867 }
1868
1869 return NOTIFY_DONE;
1870 }
1871
1872 /* Update the PMTU of exceptions when:
1873 * - the new MTU of the first hop becomes smaller than the PMTU
1874 * - the old MTU was the same as the PMTU, and it limited discovery of
1875 * larger MTUs on the path. With that limit raised, we can now
1876 * discover larger MTUs
1877 * A special case is locked exceptions, for which the PMTU is smaller
1878 * than the minimal accepted PMTU:
1879 * - if the new MTU is greater than the PMTU, don't make any change
1880 * - otherwise, unlock and set PMTU
1881 */
fib_nhc_update_mtu(struct fib_nh_common * nhc,u32 new,u32 orig)1882 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1883 {
1884 struct fnhe_hash_bucket *bucket;
1885 int i;
1886
1887 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1888 if (!bucket)
1889 return;
1890
1891 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1892 struct fib_nh_exception *fnhe;
1893
1894 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1895 fnhe;
1896 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1897 if (fnhe->fnhe_mtu_locked) {
1898 if (new <= fnhe->fnhe_pmtu) {
1899 fnhe->fnhe_pmtu = new;
1900 fnhe->fnhe_mtu_locked = false;
1901 }
1902 } else if (new < fnhe->fnhe_pmtu ||
1903 orig == fnhe->fnhe_pmtu) {
1904 fnhe->fnhe_pmtu = new;
1905 }
1906 }
1907 }
1908 }
1909
fib_sync_mtu(struct net_device * dev,u32 orig_mtu)1910 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1911 {
1912 struct hlist_head *head = fib_nh_head(dev);
1913 struct fib_nh *nh;
1914
1915 hlist_for_each_entry(nh, head, nh_hash) {
1916 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
1917 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1918 }
1919 }
1920
1921 /* Event force Flags Description
1922 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1923 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1924 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1925 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1926 *
1927 * only used when fib_nh is built into fib_info
1928 */
fib_sync_down_dev(struct net_device * dev,unsigned long event,bool force)1929 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1930 {
1931 struct hlist_head *head = fib_nh_head(dev);
1932 struct fib_info *prev_fi = NULL;
1933 int scope = RT_SCOPE_NOWHERE;
1934 struct fib_nh *nh;
1935 int ret = 0;
1936
1937 if (force)
1938 scope = -1;
1939
1940 hlist_for_each_entry(nh, head, nh_hash) {
1941 struct fib_info *fi = nh->nh_parent;
1942 int dead;
1943
1944 BUG_ON(!fi->fib_nhs);
1945 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
1946 if (fi == prev_fi)
1947 continue;
1948 prev_fi = fi;
1949 dead = 0;
1950 change_nexthops(fi) {
1951 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1952 dead++;
1953 else if (nexthop_nh->fib_nh_dev == dev &&
1954 nexthop_nh->fib_nh_scope != scope) {
1955 switch (event) {
1956 case NETDEV_DOWN:
1957 case NETDEV_UNREGISTER:
1958 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1959 fallthrough;
1960 case NETDEV_CHANGE:
1961 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1962 break;
1963 }
1964 call_fib_nh_notifiers(nexthop_nh,
1965 FIB_EVENT_NH_DEL);
1966 dead++;
1967 }
1968 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1969 if (event == NETDEV_UNREGISTER &&
1970 nexthop_nh->fib_nh_dev == dev) {
1971 dead = fi->fib_nhs;
1972 break;
1973 }
1974 #endif
1975 } endfor_nexthops(fi)
1976 if (dead == fi->fib_nhs) {
1977 switch (event) {
1978 case NETDEV_DOWN:
1979 case NETDEV_UNREGISTER:
1980 fi->fib_flags |= RTNH_F_DEAD;
1981 fallthrough;
1982 case NETDEV_CHANGE:
1983 fi->fib_flags |= RTNH_F_LINKDOWN;
1984 break;
1985 }
1986 ret++;
1987 }
1988
1989 fib_rebalance(fi);
1990 }
1991
1992 return ret;
1993 }
1994
1995 /* Must be invoked inside of an RCU protected region. */
fib_select_default(const struct flowi4 * flp,struct fib_result * res)1996 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1997 {
1998 struct fib_info *fi = NULL, *last_resort = NULL;
1999 struct hlist_head *fa_head = res->fa_head;
2000 struct fib_table *tb = res->table;
2001 u8 slen = 32 - res->prefixlen;
2002 int order = -1, last_idx = -1;
2003 struct fib_alias *fa, *fa1 = NULL;
2004 u32 last_prio = res->fi->fib_priority;
2005 dscp_t last_dscp = 0;
2006
2007 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2008 struct fib_info *next_fi = fa->fa_info;
2009 struct fib_nh_common *nhc;
2010
2011 if (fa->fa_slen != slen)
2012 continue;
2013 if (fa->fa_dscp && !fib_dscp_masked_match(fa->fa_dscp, flp))
2014 continue;
2015 if (fa->tb_id != tb->tb_id)
2016 continue;
2017 if (next_fi->fib_priority > last_prio &&
2018 fa->fa_dscp == last_dscp) {
2019 if (last_dscp)
2020 continue;
2021 break;
2022 }
2023 if (next_fi->fib_flags & RTNH_F_DEAD)
2024 continue;
2025 last_dscp = fa->fa_dscp;
2026 last_prio = next_fi->fib_priority;
2027
2028 if (next_fi->fib_scope != res->scope ||
2029 fa->fa_type != RTN_UNICAST)
2030 continue;
2031
2032 nhc = fib_info_nhc(next_fi, 0);
2033 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2034 continue;
2035
2036 fib_alias_accessed(fa);
2037
2038 if (!fi) {
2039 if (next_fi != res->fi)
2040 break;
2041 fa1 = fa;
2042 } else if (!fib_detect_death(fi, order, &last_resort,
2043 &last_idx, fa1->fa_default)) {
2044 fib_result_assign(res, fi);
2045 fa1->fa_default = order;
2046 goto out;
2047 }
2048 fi = next_fi;
2049 order++;
2050 }
2051
2052 if (order <= 0 || !fi) {
2053 if (fa1)
2054 fa1->fa_default = -1;
2055 goto out;
2056 }
2057
2058 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2059 fa1->fa_default)) {
2060 fib_result_assign(res, fi);
2061 fa1->fa_default = order;
2062 goto out;
2063 }
2064
2065 if (last_idx >= 0)
2066 fib_result_assign(res, last_resort);
2067 fa1->fa_default = last_idx;
2068 out:
2069 return;
2070 }
2071
2072 /*
2073 * Dead device goes up. We wake up dead nexthops.
2074 * It takes sense only on multipath routes.
2075 *
2076 * only used when fib_nh is built into fib_info
2077 */
fib_sync_up(struct net_device * dev,unsigned char nh_flags)2078 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2079 {
2080 struct fib_info *prev_fi;
2081 struct hlist_head *head;
2082 struct fib_nh *nh;
2083 int ret;
2084
2085 if (!(dev->flags & IFF_UP))
2086 return 0;
2087
2088 if (nh_flags & RTNH_F_DEAD) {
2089 unsigned int flags = netif_get_flags(dev);
2090
2091 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2092 nh_flags |= RTNH_F_LINKDOWN;
2093 }
2094
2095 prev_fi = NULL;
2096 head = fib_nh_head(dev);
2097 ret = 0;
2098
2099 hlist_for_each_entry(nh, head, nh_hash) {
2100 struct fib_info *fi = nh->nh_parent;
2101 int alive;
2102
2103 BUG_ON(!fi->fib_nhs);
2104 DEBUG_NET_WARN_ON_ONCE(nh->fib_nh_dev != dev);
2105 if (fi == prev_fi)
2106 continue;
2107
2108 prev_fi = fi;
2109 alive = 0;
2110 change_nexthops(fi) {
2111 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2112 alive++;
2113 continue;
2114 }
2115 if (!nexthop_nh->fib_nh_dev ||
2116 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2117 continue;
2118 if (nexthop_nh->fib_nh_dev != dev ||
2119 !__in_dev_get_rtnl(dev))
2120 continue;
2121 alive++;
2122 nexthop_nh->fib_nh_flags &= ~nh_flags;
2123 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2124 } endfor_nexthops(fi)
2125
2126 if (alive > 0) {
2127 fi->fib_flags &= ~nh_flags;
2128 ret++;
2129 }
2130
2131 fib_rebalance(fi);
2132 }
2133
2134 return ret;
2135 }
2136
2137 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_good_nh(const struct fib_nh * nh)2138 static bool fib_good_nh(const struct fib_nh *nh)
2139 {
2140 int state = NUD_REACHABLE;
2141
2142 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2143 struct neighbour *n;
2144
2145 rcu_read_lock();
2146
2147 if (likely(nh->fib_nh_gw_family == AF_INET))
2148 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2149 (__force u32)nh->fib_nh_gw4);
2150 else if (nh->fib_nh_gw_family == AF_INET6)
2151 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2152 &nh->fib_nh_gw6);
2153 else
2154 n = NULL;
2155 if (n)
2156 state = READ_ONCE(n->nud_state);
2157
2158 rcu_read_unlock();
2159 }
2160
2161 return !!(state & NUD_VALID);
2162 }
2163
fib_select_multipath(struct fib_result * res,int hash,const struct flowi4 * fl4)2164 void fib_select_multipath(struct fib_result *res, int hash,
2165 const struct flowi4 *fl4)
2166 {
2167 struct fib_info *fi = res->fi;
2168 struct net *net = fi->fib_net;
2169 bool use_neigh;
2170 int score = -1;
2171 __be32 saddr;
2172
2173 if (unlikely(res->fi->nh)) {
2174 nexthop_path_fib_result(res, hash);
2175 return;
2176 }
2177
2178 use_neigh = READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh);
2179 saddr = fl4 ? fl4->saddr : 0;
2180
2181 change_nexthops(fi) {
2182 int nh_upper_bound, nh_score = 0;
2183
2184 /* Nexthops without a carrier are assigned an upper bound of
2185 * minus one when "ignore_routes_with_linkdown" is set.
2186 */
2187 nh_upper_bound = atomic_read(&nexthop_nh->fib_nh_upper_bound);
2188 if (nh_upper_bound == -1 ||
2189 (use_neigh && !fib_good_nh(nexthop_nh)))
2190 continue;
2191
2192 if (saddr && nexthop_nh->nh_saddr == saddr)
2193 nh_score += 2;
2194 if (hash <= nh_upper_bound)
2195 nh_score++;
2196 if (score < nh_score) {
2197 res->nh_sel = nhsel;
2198 res->nhc = &nexthop_nh->nh_common;
2199 if (nh_score == 3 || (!saddr && nh_score == 1))
2200 return;
2201 score = nh_score;
2202 }
2203
2204 } endfor_nexthops(fi);
2205 }
2206 #endif
2207
fib_select_path(struct net * net,struct fib_result * res,struct flowi4 * fl4,const struct sk_buff * skb)2208 void fib_select_path(struct net *net, struct fib_result *res,
2209 struct flowi4 *fl4, const struct sk_buff *skb)
2210 {
2211 if (fl4->flowi4_oif)
2212 goto check_saddr;
2213
2214 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2215 if (fib_info_num_path(res->fi) > 1) {
2216 int h = fib_multipath_hash(net, fl4, skb, NULL);
2217
2218 fib_select_multipath(res, h, fl4);
2219 }
2220 else
2221 #endif
2222 if (!res->prefixlen &&
2223 res->table->tb_num_default > 1 &&
2224 res->type == RTN_UNICAST)
2225 fib_select_default(fl4, res);
2226
2227 check_saddr:
2228 if (!fl4->saddr) {
2229 struct net_device *l3mdev;
2230
2231 l3mdev = dev_get_by_index_rcu(net, fl4->flowi4_l3mdev);
2232
2233 if (!l3mdev ||
2234 l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) == l3mdev)
2235 fl4->saddr = fib_result_prefsrc(net, res);
2236 else
2237 fl4->saddr = inet_select_addr(l3mdev, 0, RT_SCOPE_LINK);
2238 }
2239 }
2240
fib4_semantics_init(struct net * net)2241 int __net_init fib4_semantics_init(struct net *net)
2242 {
2243 unsigned int hash_bits = 4;
2244
2245 net->ipv4.fib_info_hash = fib_info_hash_alloc(hash_bits);
2246 if (!net->ipv4.fib_info_hash)
2247 return -ENOMEM;
2248
2249 net->ipv4.fib_info_hash_bits = hash_bits;
2250 net->ipv4.fib_info_cnt = 0;
2251
2252 return 0;
2253 }
2254
fib4_semantics_exit(struct net * net)2255 void __net_exit fib4_semantics_exit(struct net *net)
2256 {
2257 fib_info_hash_free(net->ipv4.fib_info_hash);
2258 }
2259