1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: semantics.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/uaccess.h>
13 #include <linux/bitops.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/jiffies.h>
17 #include <linux/mm.h>
18 #include <linux/string.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/errno.h>
22 #include <linux/in.h>
23 #include <linux/inet.h>
24 #include <linux/inetdevice.h>
25 #include <linux/netdevice.h>
26 #include <linux/if_arp.h>
27 #include <linux/proc_fs.h>
28 #include <linux/skbuff.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/netlink.h>
32 #include <linux/hash.h>
33
34 #include <net/arp.h>
35 #include <net/inet_dscp.h>
36 #include <net/ip.h>
37 #include <net/protocol.h>
38 #include <net/route.h>
39 #include <net/tcp.h>
40 #include <net/sock.h>
41 #include <net/ip_fib.h>
42 #include <net/ip6_fib.h>
43 #include <net/nexthop.h>
44 #include <net/netlink.h>
45 #include <net/rtnh.h>
46 #include <net/lwtunnel.h>
47 #include <net/fib_notifier.h>
48 #include <net/addrconf.h>
49
50 #include "fib_lookup.h"
51
52 static DEFINE_SPINLOCK(fib_info_lock);
53 static struct hlist_head *fib_info_hash;
54 static struct hlist_head *fib_info_laddrhash;
55 static unsigned int fib_info_hash_size;
56 static unsigned int fib_info_hash_bits;
57 static unsigned int fib_info_cnt;
58
59 #define DEVINDEX_HASHBITS 8
60 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
61 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
62
63 /* for_nexthops and change_nexthops only used when nexthop object
64 * is not set in a fib_info. The logic within can reference fib_nh.
65 */
66 #ifdef CONFIG_IP_ROUTE_MULTIPATH
67
68 #define for_nexthops(fi) { \
69 int nhsel; const struct fib_nh *nh; \
70 for (nhsel = 0, nh = (fi)->fib_nh; \
71 nhsel < fib_info_num_path((fi)); \
72 nh++, nhsel++)
73
74 #define change_nexthops(fi) { \
75 int nhsel; struct fib_nh *nexthop_nh; \
76 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
77 nhsel < fib_info_num_path((fi)); \
78 nexthop_nh++, nhsel++)
79
80 #else /* CONFIG_IP_ROUTE_MULTIPATH */
81
82 /* Hope, that gcc will optimize it to get rid of dummy loop */
83
84 #define for_nexthops(fi) { \
85 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
86 for (nhsel = 0; nhsel < 1; nhsel++)
87
88 #define change_nexthops(fi) { \
89 int nhsel; \
90 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
91 for (nhsel = 0; nhsel < 1; nhsel++)
92
93 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
94
95 #define endfor_nexthops(fi) }
96
97
98 const struct fib_prop fib_props[RTN_MAX + 1] = {
99 [RTN_UNSPEC] = {
100 .error = 0,
101 .scope = RT_SCOPE_NOWHERE,
102 },
103 [RTN_UNICAST] = {
104 .error = 0,
105 .scope = RT_SCOPE_UNIVERSE,
106 },
107 [RTN_LOCAL] = {
108 .error = 0,
109 .scope = RT_SCOPE_HOST,
110 },
111 [RTN_BROADCAST] = {
112 .error = 0,
113 .scope = RT_SCOPE_LINK,
114 },
115 [RTN_ANYCAST] = {
116 .error = 0,
117 .scope = RT_SCOPE_LINK,
118 },
119 [RTN_MULTICAST] = {
120 .error = 0,
121 .scope = RT_SCOPE_UNIVERSE,
122 },
123 [RTN_BLACKHOLE] = {
124 .error = -EINVAL,
125 .scope = RT_SCOPE_UNIVERSE,
126 },
127 [RTN_UNREACHABLE] = {
128 .error = -EHOSTUNREACH,
129 .scope = RT_SCOPE_UNIVERSE,
130 },
131 [RTN_PROHIBIT] = {
132 .error = -EACCES,
133 .scope = RT_SCOPE_UNIVERSE,
134 },
135 [RTN_THROW] = {
136 .error = -EAGAIN,
137 .scope = RT_SCOPE_UNIVERSE,
138 },
139 [RTN_NAT] = {
140 .error = -EINVAL,
141 .scope = RT_SCOPE_NOWHERE,
142 },
143 [RTN_XRESOLVE] = {
144 .error = -EINVAL,
145 .scope = RT_SCOPE_NOWHERE,
146 },
147 };
148
rt_fibinfo_free(struct rtable __rcu ** rtp)149 static void rt_fibinfo_free(struct rtable __rcu **rtp)
150 {
151 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
152
153 if (!rt)
154 return;
155
156 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
157 * because we waited an RCU grace period before calling
158 * free_fib_info_rcu()
159 */
160
161 dst_dev_put(&rt->dst);
162 dst_release_immediate(&rt->dst);
163 }
164
free_nh_exceptions(struct fib_nh_common * nhc)165 static void free_nh_exceptions(struct fib_nh_common *nhc)
166 {
167 struct fnhe_hash_bucket *hash;
168 int i;
169
170 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
171 if (!hash)
172 return;
173 for (i = 0; i < FNHE_HASH_SIZE; i++) {
174 struct fib_nh_exception *fnhe;
175
176 fnhe = rcu_dereference_protected(hash[i].chain, 1);
177 while (fnhe) {
178 struct fib_nh_exception *next;
179
180 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
181
182 rt_fibinfo_free(&fnhe->fnhe_rth_input);
183 rt_fibinfo_free(&fnhe->fnhe_rth_output);
184
185 kfree(fnhe);
186
187 fnhe = next;
188 }
189 }
190 kfree(hash);
191 }
192
rt_fibinfo_free_cpus(struct rtable __rcu * __percpu * rtp)193 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
194 {
195 int cpu;
196
197 if (!rtp)
198 return;
199
200 for_each_possible_cpu(cpu) {
201 struct rtable *rt;
202
203 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
204 if (rt) {
205 dst_dev_put(&rt->dst);
206 dst_release_immediate(&rt->dst);
207 }
208 }
209 free_percpu(rtp);
210 }
211
fib_nh_common_release(struct fib_nh_common * nhc)212 void fib_nh_common_release(struct fib_nh_common *nhc)
213 {
214 netdev_put(nhc->nhc_dev, &nhc->nhc_dev_tracker);
215 lwtstate_put(nhc->nhc_lwtstate);
216 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
217 rt_fibinfo_free(&nhc->nhc_rth_input);
218 free_nh_exceptions(nhc);
219 }
220 EXPORT_SYMBOL_GPL(fib_nh_common_release);
221
fib_nh_release(struct net * net,struct fib_nh * fib_nh)222 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
223 {
224 #ifdef CONFIG_IP_ROUTE_CLASSID
225 if (fib_nh->nh_tclassid)
226 atomic_dec(&net->ipv4.fib_num_tclassid_users);
227 #endif
228 fib_nh_common_release(&fib_nh->nh_common);
229 }
230
231 /* Release a nexthop info record */
free_fib_info_rcu(struct rcu_head * head)232 static void free_fib_info_rcu(struct rcu_head *head)
233 {
234 struct fib_info *fi = container_of(head, struct fib_info, rcu);
235
236 if (fi->nh) {
237 nexthop_put(fi->nh);
238 } else {
239 change_nexthops(fi) {
240 fib_nh_release(fi->fib_net, nexthop_nh);
241 } endfor_nexthops(fi);
242 }
243
244 ip_fib_metrics_put(fi->fib_metrics);
245
246 kfree(fi);
247 }
248
free_fib_info(struct fib_info * fi)249 void free_fib_info(struct fib_info *fi)
250 {
251 if (fi->fib_dead == 0) {
252 pr_warn("Freeing alive fib_info %p\n", fi);
253 return;
254 }
255
256 call_rcu(&fi->rcu, free_fib_info_rcu);
257 }
258 EXPORT_SYMBOL_GPL(free_fib_info);
259
fib_release_info(struct fib_info * fi)260 void fib_release_info(struct fib_info *fi)
261 {
262 spin_lock_bh(&fib_info_lock);
263 if (fi && refcount_dec_and_test(&fi->fib_treeref)) {
264 hlist_del(&fi->fib_hash);
265
266 /* Paired with READ_ONCE() in fib_create_info(). */
267 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
268
269 if (fi->fib_prefsrc)
270 hlist_del(&fi->fib_lhash);
271 if (fi->nh) {
272 list_del(&fi->nh_list);
273 } else {
274 change_nexthops(fi) {
275 if (!nexthop_nh->fib_nh_dev)
276 continue;
277 hlist_del(&nexthop_nh->nh_hash);
278 } endfor_nexthops(fi)
279 }
280 fi->fib_dead = 1;
281 fib_info_put(fi);
282 }
283 spin_unlock_bh(&fib_info_lock);
284 }
285
nh_comp(struct fib_info * fi,struct fib_info * ofi)286 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
287 {
288 const struct fib_nh *onh;
289
290 if (fi->nh || ofi->nh)
291 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
292
293 if (ofi->fib_nhs == 0)
294 return 0;
295
296 for_nexthops(fi) {
297 onh = fib_info_nh(ofi, nhsel);
298
299 if (nh->fib_nh_oif != onh->fib_nh_oif ||
300 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
301 nh->fib_nh_scope != onh->fib_nh_scope ||
302 #ifdef CONFIG_IP_ROUTE_MULTIPATH
303 nh->fib_nh_weight != onh->fib_nh_weight ||
304 #endif
305 #ifdef CONFIG_IP_ROUTE_CLASSID
306 nh->nh_tclassid != onh->nh_tclassid ||
307 #endif
308 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
309 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
310 return -1;
311
312 if (nh->fib_nh_gw_family == AF_INET &&
313 nh->fib_nh_gw4 != onh->fib_nh_gw4)
314 return -1;
315
316 if (nh->fib_nh_gw_family == AF_INET6 &&
317 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
318 return -1;
319 } endfor_nexthops(fi);
320 return 0;
321 }
322
fib_devindex_hashfn(unsigned int val)323 static inline unsigned int fib_devindex_hashfn(unsigned int val)
324 {
325 return hash_32(val, DEVINDEX_HASHBITS);
326 }
327
328 static struct hlist_head *
fib_info_devhash_bucket(const struct net_device * dev)329 fib_info_devhash_bucket(const struct net_device *dev)
330 {
331 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
332
333 return &fib_info_devhash[fib_devindex_hashfn(val)];
334 }
335
fib_info_hashfn_1(int init_val,u8 protocol,u8 scope,u32 prefsrc,u32 priority)336 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
337 u32 prefsrc, u32 priority)
338 {
339 unsigned int val = init_val;
340
341 val ^= (protocol << 8) | scope;
342 val ^= prefsrc;
343 val ^= priority;
344
345 return val;
346 }
347
fib_info_hashfn_result(unsigned int val)348 static unsigned int fib_info_hashfn_result(unsigned int val)
349 {
350 unsigned int mask = (fib_info_hash_size - 1);
351
352 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
353 }
354
fib_info_hashfn(struct fib_info * fi)355 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
356 {
357 unsigned int val;
358
359 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
360 fi->fib_scope, (__force u32)fi->fib_prefsrc,
361 fi->fib_priority);
362
363 if (fi->nh) {
364 val ^= fib_devindex_hashfn(fi->nh->id);
365 } else {
366 for_nexthops(fi) {
367 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
368 } endfor_nexthops(fi)
369 }
370
371 return fib_info_hashfn_result(val);
372 }
373
374 /* no metrics, only nexthop id */
fib_find_info_nh(struct net * net,const struct fib_config * cfg)375 static struct fib_info *fib_find_info_nh(struct net *net,
376 const struct fib_config *cfg)
377 {
378 struct hlist_head *head;
379 struct fib_info *fi;
380 unsigned int hash;
381
382 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
383 cfg->fc_protocol, cfg->fc_scope,
384 (__force u32)cfg->fc_prefsrc,
385 cfg->fc_priority);
386 hash = fib_info_hashfn_result(hash);
387 head = &fib_info_hash[hash];
388
389 hlist_for_each_entry(fi, head, fib_hash) {
390 if (!net_eq(fi->fib_net, net))
391 continue;
392 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
393 continue;
394 if (cfg->fc_protocol == fi->fib_protocol &&
395 cfg->fc_scope == fi->fib_scope &&
396 cfg->fc_prefsrc == fi->fib_prefsrc &&
397 cfg->fc_priority == fi->fib_priority &&
398 cfg->fc_type == fi->fib_type &&
399 cfg->fc_table == fi->fib_tb_id &&
400 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
401 return fi;
402 }
403
404 return NULL;
405 }
406
fib_find_info(struct fib_info * nfi)407 static struct fib_info *fib_find_info(struct fib_info *nfi)
408 {
409 struct hlist_head *head;
410 struct fib_info *fi;
411 unsigned int hash;
412
413 hash = fib_info_hashfn(nfi);
414 head = &fib_info_hash[hash];
415
416 hlist_for_each_entry(fi, head, fib_hash) {
417 if (!net_eq(fi->fib_net, nfi->fib_net))
418 continue;
419 if (fi->fib_nhs != nfi->fib_nhs)
420 continue;
421 if (nfi->fib_protocol == fi->fib_protocol &&
422 nfi->fib_scope == fi->fib_scope &&
423 nfi->fib_prefsrc == fi->fib_prefsrc &&
424 nfi->fib_priority == fi->fib_priority &&
425 nfi->fib_type == fi->fib_type &&
426 nfi->fib_tb_id == fi->fib_tb_id &&
427 memcmp(nfi->fib_metrics, fi->fib_metrics,
428 sizeof(u32) * RTAX_MAX) == 0 &&
429 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
430 nh_comp(fi, nfi) == 0)
431 return fi;
432 }
433
434 return NULL;
435 }
436
437 /* Check, that the gateway is already configured.
438 * Used only by redirect accept routine.
439 */
ip_fib_check_default(__be32 gw,struct net_device * dev)440 int ip_fib_check_default(__be32 gw, struct net_device *dev)
441 {
442 struct hlist_head *head;
443 struct fib_nh *nh;
444
445 spin_lock(&fib_info_lock);
446
447 head = fib_info_devhash_bucket(dev);
448
449 hlist_for_each_entry(nh, head, nh_hash) {
450 if (nh->fib_nh_dev == dev &&
451 nh->fib_nh_gw4 == gw &&
452 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
453 spin_unlock(&fib_info_lock);
454 return 0;
455 }
456 }
457
458 spin_unlock(&fib_info_lock);
459
460 return -1;
461 }
462
fib_nlmsg_size(struct fib_info * fi)463 size_t fib_nlmsg_size(struct fib_info *fi)
464 {
465 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
466 + nla_total_size(4) /* RTA_TABLE */
467 + nla_total_size(4) /* RTA_DST */
468 + nla_total_size(4) /* RTA_PRIORITY */
469 + nla_total_size(4) /* RTA_PREFSRC */
470 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
471 unsigned int nhs = fib_info_num_path(fi);
472
473 /* space for nested metrics */
474 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
475
476 if (fi->nh)
477 payload += nla_total_size(4); /* RTA_NH_ID */
478
479 if (nhs) {
480 size_t nh_encapsize = 0;
481 /* Also handles the special case nhs == 1 */
482
483 /* each nexthop is packed in an attribute */
484 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
485 unsigned int i;
486
487 /* may contain flow and gateway attribute */
488 nhsize += 2 * nla_total_size(4);
489
490 /* grab encap info */
491 for (i = 0; i < fib_info_num_path(fi); i++) {
492 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
493
494 if (nhc->nhc_lwtstate) {
495 /* RTA_ENCAP_TYPE */
496 nh_encapsize += lwtunnel_get_encap_size(
497 nhc->nhc_lwtstate);
498 /* RTA_ENCAP */
499 nh_encapsize += nla_total_size(2);
500 }
501 }
502
503 /* all nexthops are packed in a nested attribute */
504 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
505
506 }
507
508 return payload;
509 }
510
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)511 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
512 int dst_len, u32 tb_id, const struct nl_info *info,
513 unsigned int nlm_flags)
514 {
515 struct fib_rt_info fri;
516 struct sk_buff *skb;
517 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
518 int err = -ENOBUFS;
519
520 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
521 if (!skb)
522 goto errout;
523
524 fri.fi = fa->fa_info;
525 fri.tb_id = tb_id;
526 fri.dst = key;
527 fri.dst_len = dst_len;
528 fri.dscp = fa->fa_dscp;
529 fri.type = fa->fa_type;
530 fri.offload = READ_ONCE(fa->offload);
531 fri.trap = READ_ONCE(fa->trap);
532 fri.offload_failed = READ_ONCE(fa->offload_failed);
533 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
534 if (err < 0) {
535 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
536 WARN_ON(err == -EMSGSIZE);
537 kfree_skb(skb);
538 goto errout;
539 }
540 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
541 info->nlh, GFP_KERNEL);
542 return;
543 errout:
544 if (err < 0)
545 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
546 }
547
fib_detect_death(struct fib_info * fi,int order,struct fib_info ** last_resort,int * last_idx,int dflt)548 static int fib_detect_death(struct fib_info *fi, int order,
549 struct fib_info **last_resort, int *last_idx,
550 int dflt)
551 {
552 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
553 struct neighbour *n;
554 int state = NUD_NONE;
555
556 if (likely(nhc->nhc_gw_family == AF_INET))
557 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
558 else if (nhc->nhc_gw_family == AF_INET6)
559 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
560 nhc->nhc_dev);
561 else
562 n = NULL;
563
564 if (n) {
565 state = n->nud_state;
566 neigh_release(n);
567 } else {
568 return 0;
569 }
570 if (state == NUD_REACHABLE)
571 return 0;
572 if ((state & NUD_VALID) && order != dflt)
573 return 0;
574 if ((state & NUD_VALID) ||
575 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
576 *last_resort = fi;
577 *last_idx = order;
578 }
579 return 1;
580 }
581
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)582 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
583 struct nlattr *encap, u16 encap_type,
584 void *cfg, gfp_t gfp_flags,
585 struct netlink_ext_ack *extack)
586 {
587 int err;
588
589 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
590 gfp_flags);
591 if (!nhc->nhc_pcpu_rth_output)
592 return -ENOMEM;
593
594 if (encap) {
595 struct lwtunnel_state *lwtstate;
596
597 if (encap_type == LWTUNNEL_ENCAP_NONE) {
598 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
599 err = -EINVAL;
600 goto lwt_failure;
601 }
602 err = lwtunnel_build_state(net, encap_type, encap,
603 nhc->nhc_family, cfg, &lwtstate,
604 extack);
605 if (err)
606 goto lwt_failure;
607
608 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
609 }
610
611 return 0;
612
613 lwt_failure:
614 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
615 nhc->nhc_pcpu_rth_output = NULL;
616 return err;
617 }
618 EXPORT_SYMBOL_GPL(fib_nh_common_init);
619
fib_nh_init(struct net * net,struct fib_nh * nh,struct fib_config * cfg,int nh_weight,struct netlink_ext_ack * extack)620 int fib_nh_init(struct net *net, struct fib_nh *nh,
621 struct fib_config *cfg, int nh_weight,
622 struct netlink_ext_ack *extack)
623 {
624 int err;
625
626 nh->fib_nh_family = AF_INET;
627
628 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
629 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
630 if (err)
631 return err;
632
633 nh->fib_nh_oif = cfg->fc_oif;
634 nh->fib_nh_gw_family = cfg->fc_gw_family;
635 if (cfg->fc_gw_family == AF_INET)
636 nh->fib_nh_gw4 = cfg->fc_gw4;
637 else if (cfg->fc_gw_family == AF_INET6)
638 nh->fib_nh_gw6 = cfg->fc_gw6;
639
640 nh->fib_nh_flags = cfg->fc_flags;
641
642 #ifdef CONFIG_IP_ROUTE_CLASSID
643 nh->nh_tclassid = cfg->fc_flow;
644 if (nh->nh_tclassid)
645 atomic_inc(&net->ipv4.fib_num_tclassid_users);
646 #endif
647 #ifdef CONFIG_IP_ROUTE_MULTIPATH
648 nh->fib_nh_weight = nh_weight;
649 #endif
650 return 0;
651 }
652
653 #ifdef CONFIG_IP_ROUTE_MULTIPATH
654
fib_count_nexthops(struct rtnexthop * rtnh,int remaining,struct netlink_ext_ack * extack)655 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
656 struct netlink_ext_ack *extack)
657 {
658 int nhs = 0;
659
660 while (rtnh_ok(rtnh, remaining)) {
661 nhs++;
662 rtnh = rtnh_next(rtnh, &remaining);
663 }
664
665 /* leftover implies invalid nexthop configuration, discard it */
666 if (remaining > 0) {
667 NL_SET_ERR_MSG(extack,
668 "Invalid nexthop configuration - extra data after nexthops");
669 nhs = 0;
670 }
671
672 return nhs;
673 }
674
fib_gw_from_attr(__be32 * gw,struct nlattr * nla,struct netlink_ext_ack * extack)675 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
676 struct netlink_ext_ack *extack)
677 {
678 if (nla_len(nla) < sizeof(*gw)) {
679 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
680 return -EINVAL;
681 }
682
683 *gw = nla_get_in_addr(nla);
684
685 return 0;
686 }
687
688 /* 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)689 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
690 int remaining, struct fib_config *cfg,
691 struct netlink_ext_ack *extack)
692 {
693 struct net *net = fi->fib_net;
694 struct fib_config fib_cfg;
695 struct fib_nh *nh;
696 int ret;
697
698 change_nexthops(fi) {
699 int attrlen;
700
701 memset(&fib_cfg, 0, sizeof(fib_cfg));
702
703 if (!rtnh_ok(rtnh, remaining)) {
704 NL_SET_ERR_MSG(extack,
705 "Invalid nexthop configuration - extra data after nexthop");
706 return -EINVAL;
707 }
708
709 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
710 NL_SET_ERR_MSG(extack,
711 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
712 return -EINVAL;
713 }
714
715 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
716 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
717
718 attrlen = rtnh_attrlen(rtnh);
719 if (attrlen > 0) {
720 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
721
722 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
723 nlav = nla_find(attrs, attrlen, RTA_VIA);
724 if (nla && nlav) {
725 NL_SET_ERR_MSG(extack,
726 "Nexthop configuration can not contain both GATEWAY and VIA");
727 return -EINVAL;
728 }
729 if (nla) {
730 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
731 extack);
732 if (ret)
733 goto errout;
734
735 if (fib_cfg.fc_gw4)
736 fib_cfg.fc_gw_family = AF_INET;
737 } else if (nlav) {
738 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
739 if (ret)
740 goto errout;
741 }
742
743 nla = nla_find(attrs, attrlen, RTA_FLOW);
744 if (nla) {
745 if (nla_len(nla) < sizeof(u32)) {
746 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
747 return -EINVAL;
748 }
749 fib_cfg.fc_flow = nla_get_u32(nla);
750 }
751
752 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
753 /* RTA_ENCAP_TYPE length checked in
754 * lwtunnel_valid_encap_type_attr
755 */
756 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
757 if (nla)
758 fib_cfg.fc_encap_type = nla_get_u16(nla);
759 }
760
761 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
762 rtnh->rtnh_hops + 1, extack);
763 if (ret)
764 goto errout;
765
766 rtnh = rtnh_next(rtnh, &remaining);
767 } endfor_nexthops(fi);
768
769 ret = -EINVAL;
770 nh = fib_info_nh(fi, 0);
771 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
772 NL_SET_ERR_MSG(extack,
773 "Nexthop device index does not match RTA_OIF");
774 goto errout;
775 }
776 if (cfg->fc_gw_family) {
777 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
778 (cfg->fc_gw_family == AF_INET &&
779 nh->fib_nh_gw4 != cfg->fc_gw4) ||
780 (cfg->fc_gw_family == AF_INET6 &&
781 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
782 NL_SET_ERR_MSG(extack,
783 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
784 goto errout;
785 }
786 }
787 #ifdef CONFIG_IP_ROUTE_CLASSID
788 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
789 NL_SET_ERR_MSG(extack,
790 "Nexthop class id does not match RTA_FLOW");
791 goto errout;
792 }
793 #endif
794 ret = 0;
795 errout:
796 return ret;
797 }
798
799 /* only called when fib_nh is integrated into fib_info */
fib_rebalance(struct fib_info * fi)800 static void fib_rebalance(struct fib_info *fi)
801 {
802 int total;
803 int w;
804
805 if (fib_info_num_path(fi) < 2)
806 return;
807
808 total = 0;
809 for_nexthops(fi) {
810 if (nh->fib_nh_flags & RTNH_F_DEAD)
811 continue;
812
813 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
814 nh->fib_nh_flags & RTNH_F_LINKDOWN)
815 continue;
816
817 total += nh->fib_nh_weight;
818 } endfor_nexthops(fi);
819
820 w = 0;
821 change_nexthops(fi) {
822 int upper_bound;
823
824 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
825 upper_bound = -1;
826 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
827 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
828 upper_bound = -1;
829 } else {
830 w += nexthop_nh->fib_nh_weight;
831 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
832 total) - 1;
833 }
834
835 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
836 } endfor_nexthops(fi);
837 }
838 #else /* CONFIG_IP_ROUTE_MULTIPATH */
839
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)840 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
841 int remaining, struct fib_config *cfg,
842 struct netlink_ext_ack *extack)
843 {
844 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
845
846 return -EINVAL;
847 }
848
849 #define fib_rebalance(fi) do { } while (0)
850
851 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
852
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)853 static int fib_encap_match(struct net *net, u16 encap_type,
854 struct nlattr *encap,
855 const struct fib_nh *nh,
856 const struct fib_config *cfg,
857 struct netlink_ext_ack *extack)
858 {
859 struct lwtunnel_state *lwtstate;
860 int ret, result = 0;
861
862 if (encap_type == LWTUNNEL_ENCAP_NONE)
863 return 0;
864
865 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
866 cfg, &lwtstate, extack);
867 if (!ret) {
868 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
869 lwtstate_free(lwtstate);
870 }
871
872 return result;
873 }
874
fib_nh_match(struct net * net,struct fib_config * cfg,struct fib_info * fi,struct netlink_ext_ack * extack)875 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
876 struct netlink_ext_ack *extack)
877 {
878 #ifdef CONFIG_IP_ROUTE_MULTIPATH
879 struct rtnexthop *rtnh;
880 int remaining;
881 #endif
882
883 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
884 return 1;
885
886 if (cfg->fc_nh_id) {
887 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
888 return 0;
889 return 1;
890 }
891
892 if (fi->nh) {
893 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
894 return 1;
895 return 0;
896 }
897
898 if (cfg->fc_oif || cfg->fc_gw_family) {
899 struct fib_nh *nh;
900
901 nh = fib_info_nh(fi, 0);
902 if (cfg->fc_encap) {
903 if (fib_encap_match(net, cfg->fc_encap_type,
904 cfg->fc_encap, nh, cfg, extack))
905 return 1;
906 }
907 #ifdef CONFIG_IP_ROUTE_CLASSID
908 if (cfg->fc_flow &&
909 cfg->fc_flow != nh->nh_tclassid)
910 return 1;
911 #endif
912 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
913 (cfg->fc_gw_family &&
914 cfg->fc_gw_family != nh->fib_nh_gw_family))
915 return 1;
916
917 if (cfg->fc_gw_family == AF_INET &&
918 cfg->fc_gw4 != nh->fib_nh_gw4)
919 return 1;
920
921 if (cfg->fc_gw_family == AF_INET6 &&
922 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
923 return 1;
924
925 return 0;
926 }
927
928 #ifdef CONFIG_IP_ROUTE_MULTIPATH
929 if (!cfg->fc_mp)
930 return 0;
931
932 rtnh = cfg->fc_mp;
933 remaining = cfg->fc_mp_len;
934
935 for_nexthops(fi) {
936 int attrlen;
937
938 if (!rtnh_ok(rtnh, remaining))
939 return -EINVAL;
940
941 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
942 return 1;
943
944 attrlen = rtnh_attrlen(rtnh);
945 if (attrlen > 0) {
946 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
947 int err;
948
949 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
950 nlav = nla_find(attrs, attrlen, RTA_VIA);
951 if (nla && nlav) {
952 NL_SET_ERR_MSG(extack,
953 "Nexthop configuration can not contain both GATEWAY and VIA");
954 return -EINVAL;
955 }
956
957 if (nla) {
958 __be32 gw;
959
960 err = fib_gw_from_attr(&gw, nla, extack);
961 if (err)
962 return err;
963
964 if (nh->fib_nh_gw_family != AF_INET ||
965 gw != nh->fib_nh_gw4)
966 return 1;
967 } else if (nlav) {
968 struct fib_config cfg2;
969
970 err = fib_gw_from_via(&cfg2, nlav, extack);
971 if (err)
972 return err;
973
974 switch (nh->fib_nh_gw_family) {
975 case AF_INET:
976 if (cfg2.fc_gw_family != AF_INET ||
977 cfg2.fc_gw4 != nh->fib_nh_gw4)
978 return 1;
979 break;
980 case AF_INET6:
981 if (cfg2.fc_gw_family != AF_INET6 ||
982 ipv6_addr_cmp(&cfg2.fc_gw6,
983 &nh->fib_nh_gw6))
984 return 1;
985 break;
986 }
987 }
988
989 #ifdef CONFIG_IP_ROUTE_CLASSID
990 nla = nla_find(attrs, attrlen, RTA_FLOW);
991 if (nla) {
992 if (nla_len(nla) < sizeof(u32)) {
993 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
994 return -EINVAL;
995 }
996 if (nla_get_u32(nla) != nh->nh_tclassid)
997 return 1;
998 }
999 #endif
1000 }
1001
1002 rtnh = rtnh_next(rtnh, &remaining);
1003 } endfor_nexthops(fi);
1004 #endif
1005 return 0;
1006 }
1007
fib_metrics_match(struct fib_config * cfg,struct fib_info * fi)1008 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1009 {
1010 struct nlattr *nla;
1011 int remaining;
1012
1013 if (!cfg->fc_mx)
1014 return true;
1015
1016 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1017 int type = nla_type(nla);
1018 u32 fi_val, val;
1019
1020 if (!type)
1021 continue;
1022 if (type > RTAX_MAX)
1023 return false;
1024
1025 if (type == RTAX_CC_ALGO) {
1026 char tmp[TCP_CA_NAME_MAX];
1027 bool ecn_ca = false;
1028
1029 nla_strscpy(tmp, nla, sizeof(tmp));
1030 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1031 } else {
1032 if (nla_len(nla) != sizeof(u32))
1033 return false;
1034 val = nla_get_u32(nla);
1035 }
1036
1037 fi_val = fi->fib_metrics->metrics[type - 1];
1038 if (type == RTAX_FEATURES)
1039 fi_val &= ~DST_FEATURE_ECN_CA;
1040
1041 if (fi_val != val)
1042 return false;
1043 }
1044
1045 return true;
1046 }
1047
fib_check_nh_v6_gw(struct net * net,struct fib_nh * nh,u32 table,struct netlink_ext_ack * extack)1048 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1049 u32 table, struct netlink_ext_ack *extack)
1050 {
1051 struct fib6_config cfg = {
1052 .fc_table = table,
1053 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1054 .fc_ifindex = nh->fib_nh_oif,
1055 .fc_gateway = nh->fib_nh_gw6,
1056 };
1057 struct fib6_nh fib6_nh = {};
1058 int err;
1059
1060 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1061 if (!err) {
1062 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1063 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1064 GFP_KERNEL);
1065 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1066 nh->fib_nh_scope = RT_SCOPE_LINK;
1067
1068 ipv6_stub->fib6_nh_release(&fib6_nh);
1069 }
1070
1071 return err;
1072 }
1073
1074 /*
1075 * Picture
1076 * -------
1077 *
1078 * Semantics of nexthop is very messy by historical reasons.
1079 * We have to take into account, that:
1080 * a) gateway can be actually local interface address,
1081 * so that gatewayed route is direct.
1082 * b) gateway must be on-link address, possibly
1083 * described not by an ifaddr, but also by a direct route.
1084 * c) If both gateway and interface are specified, they should not
1085 * contradict.
1086 * d) If we use tunnel routes, gateway could be not on-link.
1087 *
1088 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1089 * results in pretty ugly and hairy code with obscure logic.
1090 *
1091 * I chose to generalized it instead, so that the size
1092 * of code does not increase practically, but it becomes
1093 * much more general.
1094 * Every prefix is assigned a "scope" value: "host" is local address,
1095 * "link" is direct route,
1096 * [ ... "site" ... "interior" ... ]
1097 * and "universe" is true gateway route with global meaning.
1098 *
1099 * Every prefix refers to a set of "nexthop"s (gw, oif),
1100 * where gw must have narrower scope. This recursion stops
1101 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1102 * which means that gw is forced to be on link.
1103 *
1104 * Code is still hairy, but now it is apparently logically
1105 * consistent and very flexible. F.e. as by-product it allows
1106 * to co-exists in peace independent exterior and interior
1107 * routing processes.
1108 *
1109 * Normally it looks as following.
1110 *
1111 * {universe prefix} -> (gw, oif) [scope link]
1112 * |
1113 * |-> {link prefix} -> (gw, oif) [scope local]
1114 * |
1115 * |-> {local prefix} (terminal node)
1116 */
fib_check_nh_v4_gw(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1117 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1118 u8 scope, struct netlink_ext_ack *extack)
1119 {
1120 struct net_device *dev;
1121 struct fib_result res;
1122 int err = 0;
1123
1124 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1125 unsigned int addr_type;
1126
1127 if (scope >= RT_SCOPE_LINK) {
1128 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1129 return -EINVAL;
1130 }
1131 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1132 if (!dev) {
1133 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1134 return -ENODEV;
1135 }
1136 if (!(dev->flags & IFF_UP)) {
1137 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1138 return -ENETDOWN;
1139 }
1140 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1141 if (addr_type != RTN_UNICAST) {
1142 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1143 return -EINVAL;
1144 }
1145 if (!netif_carrier_ok(dev))
1146 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1147 nh->fib_nh_dev = dev;
1148 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1149 nh->fib_nh_scope = RT_SCOPE_LINK;
1150 return 0;
1151 }
1152 rcu_read_lock();
1153 {
1154 struct fib_table *tbl = NULL;
1155 struct flowi4 fl4 = {
1156 .daddr = nh->fib_nh_gw4,
1157 .flowi4_scope = scope + 1,
1158 .flowi4_oif = nh->fib_nh_oif,
1159 .flowi4_iif = LOOPBACK_IFINDEX,
1160 };
1161
1162 /* It is not necessary, but requires a bit of thinking */
1163 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1164 fl4.flowi4_scope = RT_SCOPE_LINK;
1165
1166 if (table && table != RT_TABLE_MAIN)
1167 tbl = fib_get_table(net, table);
1168
1169 if (tbl)
1170 err = fib_table_lookup(tbl, &fl4, &res,
1171 FIB_LOOKUP_IGNORE_LINKSTATE |
1172 FIB_LOOKUP_NOREF);
1173
1174 /* on error or if no table given do full lookup. This
1175 * is needed for example when nexthops are in the local
1176 * table rather than the given table
1177 */
1178 if (!tbl || err) {
1179 err = fib_lookup(net, &fl4, &res,
1180 FIB_LOOKUP_IGNORE_LINKSTATE);
1181 }
1182
1183 if (err) {
1184 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1185 goto out;
1186 }
1187 }
1188
1189 err = -EINVAL;
1190 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1191 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1192 goto out;
1193 }
1194 nh->fib_nh_scope = res.scope;
1195 nh->fib_nh_oif = FIB_RES_OIF(res);
1196 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1197 if (!dev) {
1198 NL_SET_ERR_MSG(extack,
1199 "No egress device for nexthop gateway");
1200 goto out;
1201 }
1202 netdev_hold(dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1203 if (!netif_carrier_ok(dev))
1204 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1205 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1206 out:
1207 rcu_read_unlock();
1208 return err;
1209 }
1210
fib_check_nh_nongw(struct net * net,struct fib_nh * nh,struct netlink_ext_ack * extack)1211 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1212 struct netlink_ext_ack *extack)
1213 {
1214 struct in_device *in_dev;
1215 int err;
1216
1217 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1218 NL_SET_ERR_MSG(extack,
1219 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1220 return -EINVAL;
1221 }
1222
1223 rcu_read_lock();
1224
1225 err = -ENODEV;
1226 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1227 if (!in_dev)
1228 goto out;
1229 err = -ENETDOWN;
1230 if (!(in_dev->dev->flags & IFF_UP)) {
1231 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1232 goto out;
1233 }
1234
1235 nh->fib_nh_dev = in_dev->dev;
1236 netdev_hold(nh->fib_nh_dev, &nh->fib_nh_dev_tracker, GFP_ATOMIC);
1237 nh->fib_nh_scope = RT_SCOPE_HOST;
1238 if (!netif_carrier_ok(nh->fib_nh_dev))
1239 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1240 err = 0;
1241 out:
1242 rcu_read_unlock();
1243 return err;
1244 }
1245
fib_check_nh(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1246 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1247 struct netlink_ext_ack *extack)
1248 {
1249 int err;
1250
1251 if (nh->fib_nh_gw_family == AF_INET)
1252 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1253 else if (nh->fib_nh_gw_family == AF_INET6)
1254 err = fib_check_nh_v6_gw(net, nh, table, extack);
1255 else
1256 err = fib_check_nh_nongw(net, nh, extack);
1257
1258 return err;
1259 }
1260
1261 static struct hlist_head *
fib_info_laddrhash_bucket(const struct net * net,__be32 val)1262 fib_info_laddrhash_bucket(const struct net *net, __be32 val)
1263 {
1264 u32 slot = hash_32(net_hash_mix(net) ^ (__force u32)val,
1265 fib_info_hash_bits);
1266
1267 return &fib_info_laddrhash[slot];
1268 }
1269
fib_info_hash_move(struct hlist_head * new_info_hash,struct hlist_head * new_laddrhash,unsigned int new_size)1270 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1271 struct hlist_head *new_laddrhash,
1272 unsigned int new_size)
1273 {
1274 struct hlist_head *old_info_hash, *old_laddrhash;
1275 unsigned int old_size = fib_info_hash_size;
1276 unsigned int i;
1277
1278 spin_lock_bh(&fib_info_lock);
1279 old_info_hash = fib_info_hash;
1280 old_laddrhash = fib_info_laddrhash;
1281 fib_info_hash_size = new_size;
1282 fib_info_hash_bits = ilog2(new_size);
1283
1284 for (i = 0; i < old_size; i++) {
1285 struct hlist_head *head = &fib_info_hash[i];
1286 struct hlist_node *n;
1287 struct fib_info *fi;
1288
1289 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1290 struct hlist_head *dest;
1291 unsigned int new_hash;
1292
1293 new_hash = fib_info_hashfn(fi);
1294 dest = &new_info_hash[new_hash];
1295 hlist_add_head(&fi->fib_hash, dest);
1296 }
1297 }
1298 fib_info_hash = new_info_hash;
1299
1300 fib_info_laddrhash = new_laddrhash;
1301 for (i = 0; i < old_size; i++) {
1302 struct hlist_head *lhead = &old_laddrhash[i];
1303 struct hlist_node *n;
1304 struct fib_info *fi;
1305
1306 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1307 struct hlist_head *ldest;
1308
1309 ldest = fib_info_laddrhash_bucket(fi->fib_net,
1310 fi->fib_prefsrc);
1311 hlist_add_head(&fi->fib_lhash, ldest);
1312 }
1313 }
1314
1315 spin_unlock_bh(&fib_info_lock);
1316
1317 kvfree(old_info_hash);
1318 kvfree(old_laddrhash);
1319 }
1320
fib_info_update_nhc_saddr(struct net * net,struct fib_nh_common * nhc,unsigned char scope)1321 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1322 unsigned char scope)
1323 {
1324 struct fib_nh *nh;
1325
1326 if (nhc->nhc_family != AF_INET)
1327 return inet_select_addr(nhc->nhc_dev, 0, scope);
1328
1329 nh = container_of(nhc, struct fib_nh, nh_common);
1330 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1331 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1332
1333 return nh->nh_saddr;
1334 }
1335
fib_result_prefsrc(struct net * net,struct fib_result * res)1336 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1337 {
1338 struct fib_nh_common *nhc = res->nhc;
1339
1340 if (res->fi->fib_prefsrc)
1341 return res->fi->fib_prefsrc;
1342
1343 if (nhc->nhc_family == AF_INET) {
1344 struct fib_nh *nh;
1345
1346 nh = container_of(nhc, struct fib_nh, nh_common);
1347 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1348 return nh->nh_saddr;
1349 }
1350
1351 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1352 }
1353
fib_valid_prefsrc(struct fib_config * cfg,__be32 fib_prefsrc)1354 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1355 {
1356 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1357 fib_prefsrc != cfg->fc_dst) {
1358 u32 tb_id = cfg->fc_table;
1359 int rc;
1360
1361 if (tb_id == RT_TABLE_MAIN)
1362 tb_id = RT_TABLE_LOCAL;
1363
1364 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1365 fib_prefsrc, tb_id);
1366
1367 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1368 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1369 fib_prefsrc, RT_TABLE_LOCAL);
1370 }
1371
1372 if (rc != RTN_LOCAL)
1373 return false;
1374 }
1375 return true;
1376 }
1377
fib_create_info(struct fib_config * cfg,struct netlink_ext_ack * extack)1378 struct fib_info *fib_create_info(struct fib_config *cfg,
1379 struct netlink_ext_ack *extack)
1380 {
1381 int err;
1382 struct fib_info *fi = NULL;
1383 struct nexthop *nh = NULL;
1384 struct fib_info *ofi;
1385 int nhs = 1;
1386 struct net *net = cfg->fc_nlinfo.nl_net;
1387
1388 if (cfg->fc_type > RTN_MAX)
1389 goto err_inval;
1390
1391 /* Fast check to catch the most weird cases */
1392 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1393 NL_SET_ERR_MSG(extack, "Invalid scope");
1394 goto err_inval;
1395 }
1396
1397 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1398 NL_SET_ERR_MSG(extack,
1399 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1400 goto err_inval;
1401 }
1402
1403 if (cfg->fc_nh_id) {
1404 if (!cfg->fc_mx) {
1405 fi = fib_find_info_nh(net, cfg);
1406 if (fi) {
1407 refcount_inc(&fi->fib_treeref);
1408 return fi;
1409 }
1410 }
1411
1412 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1413 if (!nh) {
1414 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1415 goto err_inval;
1416 }
1417 nhs = 0;
1418 }
1419
1420 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1421 if (cfg->fc_mp) {
1422 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1423 if (nhs == 0)
1424 goto err_inval;
1425 }
1426 #endif
1427
1428 err = -ENOBUFS;
1429
1430 /* Paired with WRITE_ONCE() in fib_release_info() */
1431 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) {
1432 unsigned int new_size = fib_info_hash_size << 1;
1433 struct hlist_head *new_info_hash;
1434 struct hlist_head *new_laddrhash;
1435 size_t bytes;
1436
1437 if (!new_size)
1438 new_size = 16;
1439 bytes = (size_t)new_size * sizeof(struct hlist_head *);
1440 new_info_hash = kvzalloc(bytes, GFP_KERNEL);
1441 new_laddrhash = kvzalloc(bytes, GFP_KERNEL);
1442 if (!new_info_hash || !new_laddrhash) {
1443 kvfree(new_info_hash);
1444 kvfree(new_laddrhash);
1445 } else {
1446 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1447 }
1448 if (!fib_info_hash_size)
1449 goto failure;
1450 }
1451
1452 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1453 if (!fi)
1454 goto failure;
1455 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1456 cfg->fc_mx_len, extack);
1457 if (IS_ERR(fi->fib_metrics)) {
1458 err = PTR_ERR(fi->fib_metrics);
1459 kfree(fi);
1460 return ERR_PTR(err);
1461 }
1462
1463 fi->fib_net = net;
1464 fi->fib_protocol = cfg->fc_protocol;
1465 fi->fib_scope = cfg->fc_scope;
1466 fi->fib_flags = cfg->fc_flags;
1467 fi->fib_priority = cfg->fc_priority;
1468 fi->fib_prefsrc = cfg->fc_prefsrc;
1469 fi->fib_type = cfg->fc_type;
1470 fi->fib_tb_id = cfg->fc_table;
1471
1472 fi->fib_nhs = nhs;
1473 if (nh) {
1474 if (!nexthop_get(nh)) {
1475 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1476 err = -EINVAL;
1477 } else {
1478 err = 0;
1479 fi->nh = nh;
1480 }
1481 } else {
1482 change_nexthops(fi) {
1483 nexthop_nh->nh_parent = fi;
1484 } endfor_nexthops(fi)
1485
1486 if (cfg->fc_mp)
1487 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1488 extack);
1489 else
1490 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1491 }
1492
1493 if (err != 0)
1494 goto failure;
1495
1496 if (fib_props[cfg->fc_type].error) {
1497 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1498 NL_SET_ERR_MSG(extack,
1499 "Gateway, device and multipath can not be specified for this route type");
1500 goto err_inval;
1501 }
1502 goto link_it;
1503 } else {
1504 switch (cfg->fc_type) {
1505 case RTN_UNICAST:
1506 case RTN_LOCAL:
1507 case RTN_BROADCAST:
1508 case RTN_ANYCAST:
1509 case RTN_MULTICAST:
1510 break;
1511 default:
1512 NL_SET_ERR_MSG(extack, "Invalid route type");
1513 goto err_inval;
1514 }
1515 }
1516
1517 if (cfg->fc_scope > RT_SCOPE_HOST) {
1518 NL_SET_ERR_MSG(extack, "Invalid scope");
1519 goto err_inval;
1520 }
1521
1522 if (fi->nh) {
1523 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1524 if (err)
1525 goto failure;
1526 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1527 struct fib_nh *nh = fi->fib_nh;
1528
1529 /* Local address is added. */
1530 if (nhs != 1) {
1531 NL_SET_ERR_MSG(extack,
1532 "Route with host scope can not have multiple nexthops");
1533 goto err_inval;
1534 }
1535 if (nh->fib_nh_gw_family) {
1536 NL_SET_ERR_MSG(extack,
1537 "Route with host scope can not have a gateway");
1538 goto err_inval;
1539 }
1540 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1541 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1542 err = -ENODEV;
1543 if (!nh->fib_nh_dev)
1544 goto failure;
1545 netdev_tracker_alloc(nh->fib_nh_dev, &nh->fib_nh_dev_tracker,
1546 GFP_KERNEL);
1547 } else {
1548 int linkdown = 0;
1549
1550 change_nexthops(fi) {
1551 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1552 cfg->fc_table, cfg->fc_scope,
1553 extack);
1554 if (err != 0)
1555 goto failure;
1556 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1557 linkdown++;
1558 } endfor_nexthops(fi)
1559 if (linkdown == fi->fib_nhs)
1560 fi->fib_flags |= RTNH_F_LINKDOWN;
1561 }
1562
1563 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1564 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1565 goto err_inval;
1566 }
1567
1568 if (!fi->nh) {
1569 change_nexthops(fi) {
1570 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1571 fi->fib_scope);
1572 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1573 fi->fib_nh_is_v6 = true;
1574 } endfor_nexthops(fi)
1575
1576 fib_rebalance(fi);
1577 }
1578
1579 link_it:
1580 ofi = fib_find_info(fi);
1581 if (ofi) {
1582 fi->fib_dead = 1;
1583 free_fib_info(fi);
1584 refcount_inc(&ofi->fib_treeref);
1585 return ofi;
1586 }
1587
1588 refcount_set(&fi->fib_treeref, 1);
1589 refcount_set(&fi->fib_clntref, 1);
1590 spin_lock_bh(&fib_info_lock);
1591 fib_info_cnt++;
1592 hlist_add_head(&fi->fib_hash,
1593 &fib_info_hash[fib_info_hashfn(fi)]);
1594 if (fi->fib_prefsrc) {
1595 struct hlist_head *head;
1596
1597 head = fib_info_laddrhash_bucket(net, fi->fib_prefsrc);
1598 hlist_add_head(&fi->fib_lhash, head);
1599 }
1600 if (fi->nh) {
1601 list_add(&fi->nh_list, &nh->fi_list);
1602 } else {
1603 change_nexthops(fi) {
1604 struct hlist_head *head;
1605
1606 if (!nexthop_nh->fib_nh_dev)
1607 continue;
1608 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
1609 hlist_add_head(&nexthop_nh->nh_hash, head);
1610 } endfor_nexthops(fi)
1611 }
1612 spin_unlock_bh(&fib_info_lock);
1613 return fi;
1614
1615 err_inval:
1616 err = -EINVAL;
1617
1618 failure:
1619 if (fi) {
1620 fi->fib_dead = 1;
1621 free_fib_info(fi);
1622 }
1623
1624 return ERR_PTR(err);
1625 }
1626
fib_nexthop_info(struct sk_buff * skb,const struct fib_nh_common * nhc,u8 rt_family,unsigned char * flags,bool skip_oif)1627 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1628 u8 rt_family, unsigned char *flags, bool skip_oif)
1629 {
1630 if (nhc->nhc_flags & RTNH_F_DEAD)
1631 *flags |= RTNH_F_DEAD;
1632
1633 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1634 *flags |= RTNH_F_LINKDOWN;
1635
1636 rcu_read_lock();
1637 switch (nhc->nhc_family) {
1638 case AF_INET:
1639 if (ip_ignore_linkdown(nhc->nhc_dev))
1640 *flags |= RTNH_F_DEAD;
1641 break;
1642 case AF_INET6:
1643 if (ip6_ignore_linkdown(nhc->nhc_dev))
1644 *flags |= RTNH_F_DEAD;
1645 break;
1646 }
1647 rcu_read_unlock();
1648 }
1649
1650 switch (nhc->nhc_gw_family) {
1651 case AF_INET:
1652 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1653 goto nla_put_failure;
1654 break;
1655 case AF_INET6:
1656 /* if gateway family does not match nexthop family
1657 * gateway is encoded as RTA_VIA
1658 */
1659 if (rt_family != nhc->nhc_gw_family) {
1660 int alen = sizeof(struct in6_addr);
1661 struct nlattr *nla;
1662 struct rtvia *via;
1663
1664 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1665 if (!nla)
1666 goto nla_put_failure;
1667
1668 via = nla_data(nla);
1669 via->rtvia_family = AF_INET6;
1670 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1671 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1672 &nhc->nhc_gw.ipv6) < 0) {
1673 goto nla_put_failure;
1674 }
1675 break;
1676 }
1677
1678 *flags |= (nhc->nhc_flags &
1679 (RTNH_F_ONLINK | RTNH_F_OFFLOAD | RTNH_F_TRAP));
1680
1681 if (!skip_oif && nhc->nhc_dev &&
1682 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1683 goto nla_put_failure;
1684
1685 if (nhc->nhc_lwtstate &&
1686 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1687 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1688 goto nla_put_failure;
1689
1690 return 0;
1691
1692 nla_put_failure:
1693 return -EMSGSIZE;
1694 }
1695 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1696
1697 #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)1698 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1699 int nh_weight, u8 rt_family, u32 nh_tclassid)
1700 {
1701 const struct net_device *dev = nhc->nhc_dev;
1702 struct rtnexthop *rtnh;
1703 unsigned char flags = 0;
1704
1705 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1706 if (!rtnh)
1707 goto nla_put_failure;
1708
1709 rtnh->rtnh_hops = nh_weight - 1;
1710 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1711
1712 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1713 goto nla_put_failure;
1714
1715 rtnh->rtnh_flags = flags;
1716
1717 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1718 goto nla_put_failure;
1719
1720 /* length of rtnetlink header + attributes */
1721 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1722
1723 return 0;
1724
1725 nla_put_failure:
1726 return -EMSGSIZE;
1727 }
1728 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1729 #endif
1730
1731 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1732 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1733 {
1734 struct nlattr *mp;
1735
1736 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1737 if (!mp)
1738 goto nla_put_failure;
1739
1740 if (unlikely(fi->nh)) {
1741 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1742 goto nla_put_failure;
1743 goto mp_end;
1744 }
1745
1746 for_nexthops(fi) {
1747 u32 nh_tclassid = 0;
1748 #ifdef CONFIG_IP_ROUTE_CLASSID
1749 nh_tclassid = nh->nh_tclassid;
1750 #endif
1751 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1752 AF_INET, nh_tclassid) < 0)
1753 goto nla_put_failure;
1754 } endfor_nexthops(fi);
1755
1756 mp_end:
1757 nla_nest_end(skb, mp);
1758
1759 return 0;
1760
1761 nla_put_failure:
1762 return -EMSGSIZE;
1763 }
1764 #else
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1765 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1766 {
1767 return 0;
1768 }
1769 #endif
1770
fib_dump_info(struct sk_buff * skb,u32 portid,u32 seq,int event,const struct fib_rt_info * fri,unsigned int flags)1771 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1772 const struct fib_rt_info *fri, unsigned int flags)
1773 {
1774 unsigned int nhs = fib_info_num_path(fri->fi);
1775 struct fib_info *fi = fri->fi;
1776 u32 tb_id = fri->tb_id;
1777 struct nlmsghdr *nlh;
1778 struct rtmsg *rtm;
1779
1780 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1781 if (!nlh)
1782 return -EMSGSIZE;
1783
1784 rtm = nlmsg_data(nlh);
1785 rtm->rtm_family = AF_INET;
1786 rtm->rtm_dst_len = fri->dst_len;
1787 rtm->rtm_src_len = 0;
1788 rtm->rtm_tos = inet_dscp_to_dsfield(fri->dscp);
1789 if (tb_id < 256)
1790 rtm->rtm_table = tb_id;
1791 else
1792 rtm->rtm_table = RT_TABLE_COMPAT;
1793 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1794 goto nla_put_failure;
1795 rtm->rtm_type = fri->type;
1796 rtm->rtm_flags = fi->fib_flags;
1797 rtm->rtm_scope = fi->fib_scope;
1798 rtm->rtm_protocol = fi->fib_protocol;
1799
1800 if (rtm->rtm_dst_len &&
1801 nla_put_in_addr(skb, RTA_DST, fri->dst))
1802 goto nla_put_failure;
1803 if (fi->fib_priority &&
1804 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1805 goto nla_put_failure;
1806 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1807 goto nla_put_failure;
1808
1809 if (fi->fib_prefsrc &&
1810 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1811 goto nla_put_failure;
1812
1813 if (fi->nh) {
1814 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1815 goto nla_put_failure;
1816 if (nexthop_is_blackhole(fi->nh))
1817 rtm->rtm_type = RTN_BLACKHOLE;
1818 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
1819 goto offload;
1820 }
1821
1822 if (nhs == 1) {
1823 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1824 unsigned char flags = 0;
1825
1826 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1827 goto nla_put_failure;
1828
1829 rtm->rtm_flags = flags;
1830 #ifdef CONFIG_IP_ROUTE_CLASSID
1831 if (nhc->nhc_family == AF_INET) {
1832 struct fib_nh *nh;
1833
1834 nh = container_of(nhc, struct fib_nh, nh_common);
1835 if (nh->nh_tclassid &&
1836 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1837 goto nla_put_failure;
1838 }
1839 #endif
1840 } else {
1841 if (fib_add_multipath(skb, fi) < 0)
1842 goto nla_put_failure;
1843 }
1844
1845 offload:
1846 if (fri->offload)
1847 rtm->rtm_flags |= RTM_F_OFFLOAD;
1848 if (fri->trap)
1849 rtm->rtm_flags |= RTM_F_TRAP;
1850 if (fri->offload_failed)
1851 rtm->rtm_flags |= RTM_F_OFFLOAD_FAILED;
1852
1853 nlmsg_end(skb, nlh);
1854 return 0;
1855
1856 nla_put_failure:
1857 nlmsg_cancel(skb, nlh);
1858 return -EMSGSIZE;
1859 }
1860
1861 /*
1862 * Update FIB if:
1863 * - local address disappeared -> we must delete all the entries
1864 * referring to it.
1865 * - device went down -> we must shutdown all nexthops going via it.
1866 */
fib_sync_down_addr(struct net_device * dev,__be32 local)1867 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1868 {
1869 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1870 struct net *net = dev_net(dev);
1871 struct hlist_head *head;
1872 struct fib_info *fi;
1873 int ret = 0;
1874
1875 if (!fib_info_laddrhash || local == 0)
1876 return 0;
1877
1878 head = fib_info_laddrhash_bucket(net, local);
1879 hlist_for_each_entry(fi, head, fib_lhash) {
1880 if (!net_eq(fi->fib_net, net) ||
1881 fi->fib_tb_id != tb_id)
1882 continue;
1883 if (fi->fib_prefsrc == local) {
1884 fi->fib_flags |= RTNH_F_DEAD;
1885 ret++;
1886 }
1887 }
1888 return ret;
1889 }
1890
call_fib_nh_notifiers(struct fib_nh * nh,enum fib_event_type event_type)1891 static int call_fib_nh_notifiers(struct fib_nh *nh,
1892 enum fib_event_type event_type)
1893 {
1894 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1895 struct fib_nh_notifier_info info = {
1896 .fib_nh = nh,
1897 };
1898
1899 switch (event_type) {
1900 case FIB_EVENT_NH_ADD:
1901 if (nh->fib_nh_flags & RTNH_F_DEAD)
1902 break;
1903 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1904 break;
1905 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1906 &info.info);
1907 case FIB_EVENT_NH_DEL:
1908 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1909 (nh->fib_nh_flags & RTNH_F_DEAD))
1910 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1911 event_type, &info.info);
1912 break;
1913 default:
1914 break;
1915 }
1916
1917 return NOTIFY_DONE;
1918 }
1919
1920 /* Update the PMTU of exceptions when:
1921 * - the new MTU of the first hop becomes smaller than the PMTU
1922 * - the old MTU was the same as the PMTU, and it limited discovery of
1923 * larger MTUs on the path. With that limit raised, we can now
1924 * discover larger MTUs
1925 * A special case is locked exceptions, for which the PMTU is smaller
1926 * than the minimal accepted PMTU:
1927 * - if the new MTU is greater than the PMTU, don't make any change
1928 * - otherwise, unlock and set PMTU
1929 */
fib_nhc_update_mtu(struct fib_nh_common * nhc,u32 new,u32 orig)1930 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1931 {
1932 struct fnhe_hash_bucket *bucket;
1933 int i;
1934
1935 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1936 if (!bucket)
1937 return;
1938
1939 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1940 struct fib_nh_exception *fnhe;
1941
1942 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1943 fnhe;
1944 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1945 if (fnhe->fnhe_mtu_locked) {
1946 if (new <= fnhe->fnhe_pmtu) {
1947 fnhe->fnhe_pmtu = new;
1948 fnhe->fnhe_mtu_locked = false;
1949 }
1950 } else if (new < fnhe->fnhe_pmtu ||
1951 orig == fnhe->fnhe_pmtu) {
1952 fnhe->fnhe_pmtu = new;
1953 }
1954 }
1955 }
1956 }
1957
fib_sync_mtu(struct net_device * dev,u32 orig_mtu)1958 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1959 {
1960 struct hlist_head *head = fib_info_devhash_bucket(dev);
1961 struct fib_nh *nh;
1962
1963 hlist_for_each_entry(nh, head, nh_hash) {
1964 if (nh->fib_nh_dev == dev)
1965 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1966 }
1967 }
1968
1969 /* Event force Flags Description
1970 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1971 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1972 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1973 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1974 *
1975 * only used when fib_nh is built into fib_info
1976 */
fib_sync_down_dev(struct net_device * dev,unsigned long event,bool force)1977 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1978 {
1979 struct hlist_head *head = fib_info_devhash_bucket(dev);
1980 struct fib_info *prev_fi = NULL;
1981 int scope = RT_SCOPE_NOWHERE;
1982 struct fib_nh *nh;
1983 int ret = 0;
1984
1985 if (force)
1986 scope = -1;
1987
1988 hlist_for_each_entry(nh, head, nh_hash) {
1989 struct fib_info *fi = nh->nh_parent;
1990 int dead;
1991
1992 BUG_ON(!fi->fib_nhs);
1993 if (nh->fib_nh_dev != dev || fi == prev_fi)
1994 continue;
1995 prev_fi = fi;
1996 dead = 0;
1997 change_nexthops(fi) {
1998 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1999 dead++;
2000 else if (nexthop_nh->fib_nh_dev == dev &&
2001 nexthop_nh->fib_nh_scope != scope) {
2002 switch (event) {
2003 case NETDEV_DOWN:
2004 case NETDEV_UNREGISTER:
2005 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
2006 fallthrough;
2007 case NETDEV_CHANGE:
2008 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
2009 break;
2010 }
2011 call_fib_nh_notifiers(nexthop_nh,
2012 FIB_EVENT_NH_DEL);
2013 dead++;
2014 }
2015 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2016 if (event == NETDEV_UNREGISTER &&
2017 nexthop_nh->fib_nh_dev == dev) {
2018 dead = fi->fib_nhs;
2019 break;
2020 }
2021 #endif
2022 } endfor_nexthops(fi)
2023 if (dead == fi->fib_nhs) {
2024 switch (event) {
2025 case NETDEV_DOWN:
2026 case NETDEV_UNREGISTER:
2027 fi->fib_flags |= RTNH_F_DEAD;
2028 fallthrough;
2029 case NETDEV_CHANGE:
2030 fi->fib_flags |= RTNH_F_LINKDOWN;
2031 break;
2032 }
2033 ret++;
2034 }
2035
2036 fib_rebalance(fi);
2037 }
2038
2039 return ret;
2040 }
2041
2042 /* Must be invoked inside of an RCU protected region. */
fib_select_default(const struct flowi4 * flp,struct fib_result * res)2043 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2044 {
2045 struct fib_info *fi = NULL, *last_resort = NULL;
2046 struct hlist_head *fa_head = res->fa_head;
2047 struct fib_table *tb = res->table;
2048 u8 slen = 32 - res->prefixlen;
2049 int order = -1, last_idx = -1;
2050 struct fib_alias *fa, *fa1 = NULL;
2051 u32 last_prio = res->fi->fib_priority;
2052 dscp_t last_dscp = 0;
2053
2054 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2055 struct fib_info *next_fi = fa->fa_info;
2056 struct fib_nh_common *nhc;
2057
2058 if (fa->fa_slen != slen)
2059 continue;
2060 if (fa->fa_dscp &&
2061 fa->fa_dscp != inet_dsfield_to_dscp(flp->flowi4_tos))
2062 continue;
2063 if (fa->tb_id != tb->tb_id)
2064 continue;
2065 if (next_fi->fib_priority > last_prio &&
2066 fa->fa_dscp == last_dscp) {
2067 if (last_dscp)
2068 continue;
2069 break;
2070 }
2071 if (next_fi->fib_flags & RTNH_F_DEAD)
2072 continue;
2073 last_dscp = fa->fa_dscp;
2074 last_prio = next_fi->fib_priority;
2075
2076 if (next_fi->fib_scope != res->scope ||
2077 fa->fa_type != RTN_UNICAST)
2078 continue;
2079
2080 nhc = fib_info_nhc(next_fi, 0);
2081 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2082 continue;
2083
2084 fib_alias_accessed(fa);
2085
2086 if (!fi) {
2087 if (next_fi != res->fi)
2088 break;
2089 fa1 = fa;
2090 } else if (!fib_detect_death(fi, order, &last_resort,
2091 &last_idx, fa1->fa_default)) {
2092 fib_result_assign(res, fi);
2093 fa1->fa_default = order;
2094 goto out;
2095 }
2096 fi = next_fi;
2097 order++;
2098 }
2099
2100 if (order <= 0 || !fi) {
2101 if (fa1)
2102 fa1->fa_default = -1;
2103 goto out;
2104 }
2105
2106 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2107 fa1->fa_default)) {
2108 fib_result_assign(res, fi);
2109 fa1->fa_default = order;
2110 goto out;
2111 }
2112
2113 if (last_idx >= 0)
2114 fib_result_assign(res, last_resort);
2115 fa1->fa_default = last_idx;
2116 out:
2117 return;
2118 }
2119
2120 /*
2121 * Dead device goes up. We wake up dead nexthops.
2122 * It takes sense only on multipath routes.
2123 *
2124 * only used when fib_nh is built into fib_info
2125 */
fib_sync_up(struct net_device * dev,unsigned char nh_flags)2126 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2127 {
2128 struct fib_info *prev_fi;
2129 struct hlist_head *head;
2130 struct fib_nh *nh;
2131 int ret;
2132
2133 if (!(dev->flags & IFF_UP))
2134 return 0;
2135
2136 if (nh_flags & RTNH_F_DEAD) {
2137 unsigned int flags = dev_get_flags(dev);
2138
2139 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2140 nh_flags |= RTNH_F_LINKDOWN;
2141 }
2142
2143 prev_fi = NULL;
2144 head = fib_info_devhash_bucket(dev);
2145 ret = 0;
2146
2147 hlist_for_each_entry(nh, head, nh_hash) {
2148 struct fib_info *fi = nh->nh_parent;
2149 int alive;
2150
2151 BUG_ON(!fi->fib_nhs);
2152 if (nh->fib_nh_dev != dev || fi == prev_fi)
2153 continue;
2154
2155 prev_fi = fi;
2156 alive = 0;
2157 change_nexthops(fi) {
2158 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2159 alive++;
2160 continue;
2161 }
2162 if (!nexthop_nh->fib_nh_dev ||
2163 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2164 continue;
2165 if (nexthop_nh->fib_nh_dev != dev ||
2166 !__in_dev_get_rtnl(dev))
2167 continue;
2168 alive++;
2169 nexthop_nh->fib_nh_flags &= ~nh_flags;
2170 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2171 } endfor_nexthops(fi)
2172
2173 if (alive > 0) {
2174 fi->fib_flags &= ~nh_flags;
2175 ret++;
2176 }
2177
2178 fib_rebalance(fi);
2179 }
2180
2181 return ret;
2182 }
2183
2184 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_good_nh(const struct fib_nh * nh)2185 static bool fib_good_nh(const struct fib_nh *nh)
2186 {
2187 int state = NUD_REACHABLE;
2188
2189 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2190 struct neighbour *n;
2191
2192 rcu_read_lock_bh();
2193
2194 if (likely(nh->fib_nh_gw_family == AF_INET))
2195 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2196 (__force u32)nh->fib_nh_gw4);
2197 else if (nh->fib_nh_gw_family == AF_INET6)
2198 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2199 &nh->fib_nh_gw6);
2200 else
2201 n = NULL;
2202 if (n)
2203 state = n->nud_state;
2204
2205 rcu_read_unlock_bh();
2206 }
2207
2208 return !!(state & NUD_VALID);
2209 }
2210
fib_select_multipath(struct fib_result * res,int hash)2211 void fib_select_multipath(struct fib_result *res, int hash)
2212 {
2213 struct fib_info *fi = res->fi;
2214 struct net *net = fi->fib_net;
2215 bool first = false;
2216
2217 if (unlikely(res->fi->nh)) {
2218 nexthop_path_fib_result(res, hash);
2219 return;
2220 }
2221
2222 change_nexthops(fi) {
2223 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) {
2224 if (!fib_good_nh(nexthop_nh))
2225 continue;
2226 if (!first) {
2227 res->nh_sel = nhsel;
2228 res->nhc = &nexthop_nh->nh_common;
2229 first = true;
2230 }
2231 }
2232
2233 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2234 continue;
2235
2236 res->nh_sel = nhsel;
2237 res->nhc = &nexthop_nh->nh_common;
2238 return;
2239 } endfor_nexthops(fi);
2240 }
2241 #endif
2242
fib_select_path(struct net * net,struct fib_result * res,struct flowi4 * fl4,const struct sk_buff * skb)2243 void fib_select_path(struct net *net, struct fib_result *res,
2244 struct flowi4 *fl4, const struct sk_buff *skb)
2245 {
2246 if (fl4->flowi4_oif)
2247 goto check_saddr;
2248
2249 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2250 if (fib_info_num_path(res->fi) > 1) {
2251 int h = fib_multipath_hash(net, fl4, skb, NULL);
2252
2253 fib_select_multipath(res, h);
2254 }
2255 else
2256 #endif
2257 if (!res->prefixlen &&
2258 res->table->tb_num_default > 1 &&
2259 res->type == RTN_UNICAST)
2260 fib_select_default(fl4, res);
2261
2262 check_saddr:
2263 if (!fl4->saddr)
2264 fl4->saddr = fib_result_prefsrc(net, res);
2265 }
2266
