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Linux 5.2
[linux-2.6/linux-2.6-arm.git] / net / ipv4 / fib_semantics.c
blobbfa49a88d03ae570261646730eed24d4cc27e36c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: semantics.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/uaccess.h>
13 #include <linux/bitops.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/jiffies.h>
17 #include <linux/mm.h>
18 #include <linux/string.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/errno.h>
22 #include <linux/in.h>
23 #include <linux/inet.h>
24 #include <linux/inetdevice.h>
25 #include <linux/netdevice.h>
26 #include <linux/if_arp.h>
27 #include <linux/proc_fs.h>
28 #include <linux/skbuff.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/netlink.h>
32
33 #include <net/arp.h>
34 #include <net/ip.h>
35 #include <net/protocol.h>
36 #include <net/route.h>
37 #include <net/tcp.h>
38 #include <net/sock.h>
39 #include <net/ip_fib.h>
40 #include <net/ip6_fib.h>
41 #include <net/netlink.h>
42 #include <net/rtnh.h>
43 #include <net/lwtunnel.h>
44 #include <net/fib_notifier.h>
45 #include <net/addrconf.h>
46
47 #include "fib_lookup.h"
48
49 static DEFINE_SPINLOCK(fib_info_lock);
50 static struct hlist_head *fib_info_hash;
51 static struct hlist_head *fib_info_laddrhash;
52 static unsigned int fib_info_hash_size;
53 static unsigned int fib_info_cnt;
54
55 #define DEVINDEX_HASHBITS 8
56 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59 #ifdef CONFIG_IP_ROUTE_MULTIPATH
60
61 #define for_nexthops(fi) { \
62 int nhsel; const struct fib_nh *nh; \
63 for (nhsel = 0, nh = (fi)->fib_nh; \
64 nhsel < (fi)->fib_nhs; \
65 nh++, nhsel++)
66
67 #define change_nexthops(fi) { \
68 int nhsel; struct fib_nh *nexthop_nh; \
69 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
70 nhsel < (fi)->fib_nhs; \
71 nexthop_nh++, nhsel++)
72
73 #else /* CONFIG_IP_ROUTE_MULTIPATH */
74
75 /* Hope, that gcc will optimize it to get rid of dummy loop */
76
77 #define for_nexthops(fi) { \
78 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
79 for (nhsel = 0; nhsel < 1; nhsel++)
80
81 #define change_nexthops(fi) { \
82 int nhsel; \
83 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
84 for (nhsel = 0; nhsel < 1; nhsel++)
85
86 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
87
88 #define endfor_nexthops(fi) }
89
90
91 const struct fib_prop fib_props[RTN_MAX + 1] = {
92 [RTN_UNSPEC] = {
93 .error = 0,
94 .scope = RT_SCOPE_NOWHERE,
95 },
96 [RTN_UNICAST] = {
97 .error = 0,
98 .scope = RT_SCOPE_UNIVERSE,
99 },
100 [RTN_LOCAL] = {
101 .error = 0,
102 .scope = RT_SCOPE_HOST,
103 },
104 [RTN_BROADCAST] = {
105 .error = 0,
106 .scope = RT_SCOPE_LINK,
107 },
108 [RTN_ANYCAST] = {
109 .error = 0,
110 .scope = RT_SCOPE_LINK,
111 },
112 [RTN_MULTICAST] = {
113 .error = 0,
114 .scope = RT_SCOPE_UNIVERSE,
115 },
116 [RTN_BLACKHOLE] = {
117 .error = -EINVAL,
118 .scope = RT_SCOPE_UNIVERSE,
119 },
120 [RTN_UNREACHABLE] = {
121 .error = -EHOSTUNREACH,
122 .scope = RT_SCOPE_UNIVERSE,
123 },
124 [RTN_PROHIBIT] = {
125 .error = -EACCES,
126 .scope = RT_SCOPE_UNIVERSE,
127 },
128 [RTN_THROW] = {
129 .error = -EAGAIN,
130 .scope = RT_SCOPE_UNIVERSE,
131 },
132 [RTN_NAT] = {
133 .error = -EINVAL,
134 .scope = RT_SCOPE_NOWHERE,
135 },
136 [RTN_XRESOLVE] = {
137 .error = -EINVAL,
138 .scope = RT_SCOPE_NOWHERE,
139 },
140 };
141
142 static void rt_fibinfo_free(struct rtable __rcu **rtp)
143 {
144 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
145
146 if (!rt)
147 return;
148
149 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
150 * because we waited an RCU grace period before calling
151 * free_fib_info_rcu()
152 */
153
154 dst_dev_put(&rt->dst);
155 dst_release_immediate(&rt->dst);
156 }
157
158 static void free_nh_exceptions(struct fib_nh_common *nhc)
159 {
160 struct fnhe_hash_bucket *hash;
161 int i;
162
163 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
164 if (!hash)
165 return;
166 for (i = 0; i < FNHE_HASH_SIZE; i++) {
167 struct fib_nh_exception *fnhe;
168
169 fnhe = rcu_dereference_protected(hash[i].chain, 1);
170 while (fnhe) {
171 struct fib_nh_exception *next;
172
173 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
174
175 rt_fibinfo_free(&fnhe->fnhe_rth_input);
176 rt_fibinfo_free(&fnhe->fnhe_rth_output);
177
178 kfree(fnhe);
179
180 fnhe = next;
181 }
182 }
183 kfree(hash);
184 }
185
186 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
187 {
188 int cpu;
189
190 if (!rtp)
191 return;
192
193 for_each_possible_cpu(cpu) {
194 struct rtable *rt;
195
196 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
197 if (rt) {
198 dst_dev_put(&rt->dst);
199 dst_release_immediate(&rt->dst);
200 }
201 }
202 free_percpu(rtp);
203 }
204
205 void fib_nh_common_release(struct fib_nh_common *nhc)
206 {
207 if (nhc->nhc_dev)
208 dev_put(nhc->nhc_dev);
209
210 lwtstate_put(nhc->nhc_lwtstate);
211 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
212 rt_fibinfo_free(&nhc->nhc_rth_input);
213 free_nh_exceptions(nhc);
214 }
215 EXPORT_SYMBOL_GPL(fib_nh_common_release);
216
217 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
218 {
219 #ifdef CONFIG_IP_ROUTE_CLASSID
220 if (fib_nh->nh_tclassid)
221 net->ipv4.fib_num_tclassid_users--;
222 #endif
223 fib_nh_common_release(&fib_nh->nh_common);
224 }
225
226 /* Release a nexthop info record */
227 static void free_fib_info_rcu(struct rcu_head *head)
228 {
229 struct fib_info *fi = container_of(head, struct fib_info, rcu);
230
231 change_nexthops(fi) {
232 fib_nh_release(fi->fib_net, nexthop_nh);
233 } endfor_nexthops(fi);
234
235 ip_fib_metrics_put(fi->fib_metrics);
236
237 kfree(fi);
238 }
239
240 void free_fib_info(struct fib_info *fi)
241 {
242 if (fi->fib_dead == 0) {
243 pr_warn("Freeing alive fib_info %p\n", fi);
244 return;
245 }
246 fib_info_cnt--;
247
248 call_rcu(&fi->rcu, free_fib_info_rcu);
249 }
250 EXPORT_SYMBOL_GPL(free_fib_info);
251
252 void fib_release_info(struct fib_info *fi)
253 {
254 spin_lock_bh(&fib_info_lock);
255 if (fi && --fi->fib_treeref == 0) {
256 hlist_del(&fi->fib_hash);
257 if (fi->fib_prefsrc)
258 hlist_del(&fi->fib_lhash);
259 change_nexthops(fi) {
260 if (!nexthop_nh->fib_nh_dev)
261 continue;
262 hlist_del(&nexthop_nh->nh_hash);
263 } endfor_nexthops(fi)
264 fi->fib_dead = 1;
265 fib_info_put(fi);
266 }
267 spin_unlock_bh(&fib_info_lock);
268 }
269
270 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
271 {
272 const struct fib_nh *onh = ofi->fib_nh;
273
274 for_nexthops(fi) {
275 if (nh->fib_nh_oif != onh->fib_nh_oif ||
276 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
277 nh->fib_nh_scope != onh->fib_nh_scope ||
278 #ifdef CONFIG_IP_ROUTE_MULTIPATH
279 nh->fib_nh_weight != onh->fib_nh_weight ||
280 #endif
281 #ifdef CONFIG_IP_ROUTE_CLASSID
282 nh->nh_tclassid != onh->nh_tclassid ||
283 #endif
284 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
285 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
286 return -1;
287
288 if (nh->fib_nh_gw_family == AF_INET &&
289 nh->fib_nh_gw4 != onh->fib_nh_gw4)
290 return -1;
291
292 if (nh->fib_nh_gw_family == AF_INET6 &&
293 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
294 return -1;
295
296 onh++;
297 } endfor_nexthops(fi);
298 return 0;
299 }
300
301 static inline unsigned int fib_devindex_hashfn(unsigned int val)
302 {
303 unsigned int mask = DEVINDEX_HASHSIZE - 1;
304
305 return (val ^
306 (val >> DEVINDEX_HASHBITS) ^
307 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
308 }
309
310 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
311 {
312 unsigned int mask = (fib_info_hash_size - 1);
313 unsigned int val = fi->fib_nhs;
314
315 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
316 val ^= (__force u32)fi->fib_prefsrc;
317 val ^= fi->fib_priority;
318 for_nexthops(fi) {
319 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
320 } endfor_nexthops(fi)
321
322 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
323 }
324
325 static struct fib_info *fib_find_info(const struct fib_info *nfi)
326 {
327 struct hlist_head *head;
328 struct fib_info *fi;
329 unsigned int hash;
330
331 hash = fib_info_hashfn(nfi);
332 head = &fib_info_hash[hash];
333
334 hlist_for_each_entry(fi, head, fib_hash) {
335 if (!net_eq(fi->fib_net, nfi->fib_net))
336 continue;
337 if (fi->fib_nhs != nfi->fib_nhs)
338 continue;
339 if (nfi->fib_protocol == fi->fib_protocol &&
340 nfi->fib_scope == fi->fib_scope &&
341 nfi->fib_prefsrc == fi->fib_prefsrc &&
342 nfi->fib_priority == fi->fib_priority &&
343 nfi->fib_type == fi->fib_type &&
344 memcmp(nfi->fib_metrics, fi->fib_metrics,
345 sizeof(u32) * RTAX_MAX) == 0 &&
346 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
347 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
348 return fi;
349 }
350
351 return NULL;
352 }
353
354 /* Check, that the gateway is already configured.
355 * Used only by redirect accept routine.
356 */
357 int ip_fib_check_default(__be32 gw, struct net_device *dev)
358 {
359 struct hlist_head *head;
360 struct fib_nh *nh;
361 unsigned int hash;
362
363 spin_lock(&fib_info_lock);
364
365 hash = fib_devindex_hashfn(dev->ifindex);
366 head = &fib_info_devhash[hash];
367 hlist_for_each_entry(nh, head, nh_hash) {
368 if (nh->fib_nh_dev == dev &&
369 nh->fib_nh_gw4 == gw &&
370 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
371 spin_unlock(&fib_info_lock);
372 return 0;
373 }
374 }
375
376 spin_unlock(&fib_info_lock);
377
378 return -1;
379 }
380
381 static inline size_t fib_nlmsg_size(struct fib_info *fi)
382 {
383 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
384 + nla_total_size(4) /* RTA_TABLE */
385 + nla_total_size(4) /* RTA_DST */
386 + nla_total_size(4) /* RTA_PRIORITY */
387 + nla_total_size(4) /* RTA_PREFSRC */
388 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
389
390 /* space for nested metrics */
391 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
392
393 if (fi->fib_nhs) {
394 size_t nh_encapsize = 0;
395 /* Also handles the special case fib_nhs == 1 */
396
397 /* each nexthop is packed in an attribute */
398 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
399
400 /* may contain flow and gateway attribute */
401 nhsize += 2 * nla_total_size(4);
402
403 /* grab encap info */
404 for_nexthops(fi) {
405 if (nh->fib_nh_lws) {
406 /* RTA_ENCAP_TYPE */
407 nh_encapsize += lwtunnel_get_encap_size(
408 nh->fib_nh_lws);
409 /* RTA_ENCAP */
410 nh_encapsize += nla_total_size(2);
411 }
412 } endfor_nexthops(fi);
413
414 /* all nexthops are packed in a nested attribute */
415 payload += nla_total_size((fi->fib_nhs * nhsize) +
416 nh_encapsize);
417
418 }
419
420 return payload;
421 }
422
423 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
424 int dst_len, u32 tb_id, const struct nl_info *info,
425 unsigned int nlm_flags)
426 {
427 struct sk_buff *skb;
428 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
429 int err = -ENOBUFS;
430
431 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
432 if (!skb)
433 goto errout;
434
435 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
436 fa->fa_type, key, dst_len,
437 fa->fa_tos, fa->fa_info, nlm_flags);
438 if (err < 0) {
439 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
440 WARN_ON(err == -EMSGSIZE);
441 kfree_skb(skb);
442 goto errout;
443 }
444 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
445 info->nlh, GFP_KERNEL);
446 return;
447 errout:
448 if (err < 0)
449 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
450 }
451
452 static int fib_detect_death(struct fib_info *fi, int order,
453 struct fib_info **last_resort, int *last_idx,
454 int dflt)
455 {
456 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
457 struct neighbour *n;
458 int state = NUD_NONE;
459
460 if (likely(nhc->nhc_gw_family == AF_INET))
461 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
462 else if (nhc->nhc_gw_family == AF_INET6)
463 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
464 nhc->nhc_dev);
465 else
466 n = NULL;
467
468 if (n) {
469 state = n->nud_state;
470 neigh_release(n);
471 } else {
472 return 0;
473 }
474 if (state == NUD_REACHABLE)
475 return 0;
476 if ((state & NUD_VALID) && order != dflt)
477 return 0;
478 if ((state & NUD_VALID) ||
479 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
480 *last_resort = fi;
481 *last_idx = order;
482 }
483 return 1;
484 }
485
486 int fib_nh_common_init(struct fib_nh_common *nhc, struct nlattr *encap,
487 u16 encap_type, void *cfg, gfp_t gfp_flags,
488 struct netlink_ext_ack *extack)
489 {
490 int err;
491
492 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
493 gfp_flags);
494 if (!nhc->nhc_pcpu_rth_output)
495 return -ENOMEM;
496
497 if (encap) {
498 struct lwtunnel_state *lwtstate;
499
500 if (encap_type == LWTUNNEL_ENCAP_NONE) {
501 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
502 err = -EINVAL;
503 goto lwt_failure;
504 }
505 err = lwtunnel_build_state(encap_type, encap, nhc->nhc_family,
506 cfg, &lwtstate, extack);
507 if (err)
508 goto lwt_failure;
509
510 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
511 }
512
513 return 0;
514
515 lwt_failure:
516 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
517 nhc->nhc_pcpu_rth_output = NULL;
518 return err;
519 }
520 EXPORT_SYMBOL_GPL(fib_nh_common_init);
521
522 int fib_nh_init(struct net *net, struct fib_nh *nh,
523 struct fib_config *cfg, int nh_weight,
524 struct netlink_ext_ack *extack)
525 {
526 int err;
527
528 nh->fib_nh_family = AF_INET;
529
530 err = fib_nh_common_init(&nh->nh_common, cfg->fc_encap,
531 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
532 if (err)
533 return err;
534
535 nh->fib_nh_oif = cfg->fc_oif;
536 nh->fib_nh_gw_family = cfg->fc_gw_family;
537 if (cfg->fc_gw_family == AF_INET)
538 nh->fib_nh_gw4 = cfg->fc_gw4;
539 else if (cfg->fc_gw_family == AF_INET6)
540 nh->fib_nh_gw6 = cfg->fc_gw6;
541
542 nh->fib_nh_flags = cfg->fc_flags;
543
544 #ifdef CONFIG_IP_ROUTE_CLASSID
545 nh->nh_tclassid = cfg->fc_flow;
546 if (nh->nh_tclassid)
547 net->ipv4.fib_num_tclassid_users++;
548 #endif
549 #ifdef CONFIG_IP_ROUTE_MULTIPATH
550 nh->fib_nh_weight = nh_weight;
551 #endif
552 return 0;
553 }
554
555 #ifdef CONFIG_IP_ROUTE_MULTIPATH
556
557 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
558 struct netlink_ext_ack *extack)
559 {
560 int nhs = 0;
561
562 while (rtnh_ok(rtnh, remaining)) {
563 nhs++;
564 rtnh = rtnh_next(rtnh, &remaining);
565 }
566
567 /* leftover implies invalid nexthop configuration, discard it */
568 if (remaining > 0) {
569 NL_SET_ERR_MSG(extack,
570 "Invalid nexthop configuration - extra data after nexthops");
571 nhs = 0;
572 }
573
574 return nhs;
575 }
576
577 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
578 int remaining, struct fib_config *cfg,
579 struct netlink_ext_ack *extack)
580 {
581 struct net *net = fi->fib_net;
582 struct fib_config fib_cfg;
583 int ret;
584
585 change_nexthops(fi) {
586 int attrlen;
587
588 memset(&fib_cfg, 0, sizeof(fib_cfg));
589
590 if (!rtnh_ok(rtnh, remaining)) {
591 NL_SET_ERR_MSG(extack,
592 "Invalid nexthop configuration - extra data after nexthop");
593 return -EINVAL;
594 }
595
596 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
597 NL_SET_ERR_MSG(extack,
598 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
599 return -EINVAL;
600 }
601
602 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
603 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
604
605 attrlen = rtnh_attrlen(rtnh);
606 if (attrlen > 0) {
607 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
608
609 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
610 nlav = nla_find(attrs, attrlen, RTA_VIA);
611 if (nla && nlav) {
612 NL_SET_ERR_MSG(extack,
613 "Nexthop configuration can not contain both GATEWAY and VIA");
614 return -EINVAL;
615 }
616 if (nla) {
617 fib_cfg.fc_gw4 = nla_get_in_addr(nla);
618 if (fib_cfg.fc_gw4)
619 fib_cfg.fc_gw_family = AF_INET;
620 } else if (nlav) {
621 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
622 if (ret)
623 goto errout;
624 }
625
626 nla = nla_find(attrs, attrlen, RTA_FLOW);
627 if (nla)
628 fib_cfg.fc_flow = nla_get_u32(nla);
629
630 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
631 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
632 if (nla)
633 fib_cfg.fc_encap_type = nla_get_u16(nla);
634 }
635
636 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
637 rtnh->rtnh_hops + 1, extack);
638 if (ret)
639 goto errout;
640
641 rtnh = rtnh_next(rtnh, &remaining);
642 } endfor_nexthops(fi);
643
644 ret = -EINVAL;
645 if (cfg->fc_oif && fi->fib_nh->fib_nh_oif != cfg->fc_oif) {
646 NL_SET_ERR_MSG(extack,
647 "Nexthop device index does not match RTA_OIF");
648 goto errout;
649 }
650 if (cfg->fc_gw_family) {
651 if (cfg->fc_gw_family != fi->fib_nh->fib_nh_gw_family ||
652 (cfg->fc_gw_family == AF_INET &&
653 fi->fib_nh->fib_nh_gw4 != cfg->fc_gw4) ||
654 (cfg->fc_gw_family == AF_INET6 &&
655 ipv6_addr_cmp(&fi->fib_nh->fib_nh_gw6, &cfg->fc_gw6))) {
656 NL_SET_ERR_MSG(extack,
657 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
658 goto errout;
659 }
660 }
661 #ifdef CONFIG_IP_ROUTE_CLASSID
662 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
663 NL_SET_ERR_MSG(extack,
664 "Nexthop class id does not match RTA_FLOW");
665 goto errout;
666 }
667 #endif
668 ret = 0;
669 errout:
670 return ret;
671 }
672
673 static void fib_rebalance(struct fib_info *fi)
674 {
675 int total;
676 int w;
677
678 if (fi->fib_nhs < 2)
679 return;
680
681 total = 0;
682 for_nexthops(fi) {
683 if (nh->fib_nh_flags & RTNH_F_DEAD)
684 continue;
685
686 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
687 nh->fib_nh_flags & RTNH_F_LINKDOWN)
688 continue;
689
690 total += nh->fib_nh_weight;
691 } endfor_nexthops(fi);
692
693 w = 0;
694 change_nexthops(fi) {
695 int upper_bound;
696
697 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
698 upper_bound = -1;
699 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
700 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
701 upper_bound = -1;
702 } else {
703 w += nexthop_nh->fib_nh_weight;
704 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
705 total) - 1;
706 }
707
708 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
709 } endfor_nexthops(fi);
710 }
711 #else /* CONFIG_IP_ROUTE_MULTIPATH */
712
713 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
714 int remaining, struct fib_config *cfg,
715 struct netlink_ext_ack *extack)
716 {
717 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
718
719 return -EINVAL;
720 }
721
722 #define fib_rebalance(fi) do { } while (0)
723
724 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
725
726 static int fib_encap_match(u16 encap_type,
727 struct nlattr *encap,
728 const struct fib_nh *nh,
729 const struct fib_config *cfg,
730 struct netlink_ext_ack *extack)
731 {
732 struct lwtunnel_state *lwtstate;
733 int ret, result = 0;
734
735 if (encap_type == LWTUNNEL_ENCAP_NONE)
736 return 0;
737
738 ret = lwtunnel_build_state(encap_type, encap, AF_INET,
739 cfg, &lwtstate, extack);
740 if (!ret) {
741 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
742 lwtstate_free(lwtstate);
743 }
744
745 return result;
746 }
747
748 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi,
749 struct netlink_ext_ack *extack)
750 {
751 #ifdef CONFIG_IP_ROUTE_MULTIPATH
752 struct rtnexthop *rtnh;
753 int remaining;
754 #endif
755
756 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
757 return 1;
758
759 if (cfg->fc_oif || cfg->fc_gw_family) {
760 if (cfg->fc_encap) {
761 if (fib_encap_match(cfg->fc_encap_type, cfg->fc_encap,
762 fi->fib_nh, cfg, extack))
763 return 1;
764 }
765 #ifdef CONFIG_IP_ROUTE_CLASSID
766 if (cfg->fc_flow &&
767 cfg->fc_flow != fi->fib_nh->nh_tclassid)
768 return 1;
769 #endif
770 if ((cfg->fc_oif && cfg->fc_oif != fi->fib_nh->fib_nh_oif) ||
771 (cfg->fc_gw_family &&
772 cfg->fc_gw_family != fi->fib_nh->fib_nh_gw_family))
773 return 1;
774
775 if (cfg->fc_gw_family == AF_INET &&
776 cfg->fc_gw4 != fi->fib_nh->fib_nh_gw4)
777 return 1;
778
779 if (cfg->fc_gw_family == AF_INET6 &&
780 ipv6_addr_cmp(&cfg->fc_gw6, &fi->fib_nh->fib_nh_gw6))
781 return 1;
782
783 return 0;
784 }
785
786 #ifdef CONFIG_IP_ROUTE_MULTIPATH
787 if (!cfg->fc_mp)
788 return 0;
789
790 rtnh = cfg->fc_mp;
791 remaining = cfg->fc_mp_len;
792
793 for_nexthops(fi) {
794 int attrlen;
795
796 if (!rtnh_ok(rtnh, remaining))
797 return -EINVAL;
798
799 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
800 return 1;
801
802 attrlen = rtnh_attrlen(rtnh);
803 if (attrlen > 0) {
804 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
805
806 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
807 nlav = nla_find(attrs, attrlen, RTA_VIA);
808 if (nla && nlav) {
809 NL_SET_ERR_MSG(extack,
810 "Nexthop configuration can not contain both GATEWAY and VIA");
811 return -EINVAL;
812 }
813
814 if (nla) {
815 if (nh->fib_nh_gw_family != AF_INET ||
816 nla_get_in_addr(nla) != nh->fib_nh_gw4)
817 return 1;
818 } else if (nlav) {
819 struct fib_config cfg2;
820 int err;
821
822 err = fib_gw_from_via(&cfg2, nlav, extack);
823 if (err)
824 return err;
825
826 switch (nh->fib_nh_gw_family) {
827 case AF_INET:
828 if (cfg2.fc_gw_family != AF_INET ||
829 cfg2.fc_gw4 != nh->fib_nh_gw4)
830 return 1;
831 break;
832 case AF_INET6:
833 if (cfg2.fc_gw_family != AF_INET6 ||
834 ipv6_addr_cmp(&cfg2.fc_gw6,
835 &nh->fib_nh_gw6))
836 return 1;
837 break;
838 }
839 }
840
841 #ifdef CONFIG_IP_ROUTE_CLASSID
842 nla = nla_find(attrs, attrlen, RTA_FLOW);
843 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
844 return 1;
845 #endif
846 }
847
848 rtnh = rtnh_next(rtnh, &remaining);
849 } endfor_nexthops(fi);
850 #endif
851 return 0;
852 }
853
854 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
855 {
856 struct nlattr *nla;
857 int remaining;
858
859 if (!cfg->fc_mx)
860 return true;
861
862 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
863 int type = nla_type(nla);
864 u32 fi_val, val;
865
866 if (!type)
867 continue;
868 if (type > RTAX_MAX)
869 return false;
870
871 if (type == RTAX_CC_ALGO) {
872 char tmp[TCP_CA_NAME_MAX];
873 bool ecn_ca = false;
874
875 nla_strlcpy(tmp, nla, sizeof(tmp));
876 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
877 } else {
878 if (nla_len(nla) != sizeof(u32))
879 return false;
880 val = nla_get_u32(nla);
881 }
882
883 fi_val = fi->fib_metrics->metrics[type - 1];
884 if (type == RTAX_FEATURES)
885 fi_val &= ~DST_FEATURE_ECN_CA;
886
887 if (fi_val != val)
888 return false;
889 }
890
891 return true;
892 }
893
894 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
895 u32 table, struct netlink_ext_ack *extack)
896 {
897 struct fib6_config cfg = {
898 .fc_table = table,
899 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
900 .fc_ifindex = nh->fib_nh_oif,
901 .fc_gateway = nh->fib_nh_gw6,
902 };
903 struct fib6_nh fib6_nh = {};
904 int err;
905
906 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
907 if (!err) {
908 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
909 dev_hold(nh->fib_nh_dev);
910 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
911 nh->fib_nh_scope = RT_SCOPE_LINK;
912
913 ipv6_stub->fib6_nh_release(&fib6_nh);
914 }
915
916 return err;
917 }
918
919 /*
920 * Picture
921 * -------
922 *
923 * Semantics of nexthop is very messy by historical reasons.
924 * We have to take into account, that:
925 * a) gateway can be actually local interface address,
926 * so that gatewayed route is direct.
927 * b) gateway must be on-link address, possibly
928 * described not by an ifaddr, but also by a direct route.
929 * c) If both gateway and interface are specified, they should not
930 * contradict.
931 * d) If we use tunnel routes, gateway could be not on-link.
932 *
933 * Attempt to reconcile all of these (alas, self-contradictory) conditions
934 * results in pretty ugly and hairy code with obscure logic.
935 *
936 * I chose to generalized it instead, so that the size
937 * of code does not increase practically, but it becomes
938 * much more general.
939 * Every prefix is assigned a "scope" value: "host" is local address,
940 * "link" is direct route,
941 * [ ... "site" ... "interior" ... ]
942 * and "universe" is true gateway route with global meaning.
943 *
944 * Every prefix refers to a set of "nexthop"s (gw, oif),
945 * where gw must have narrower scope. This recursion stops
946 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
947 * which means that gw is forced to be on link.
948 *
949 * Code is still hairy, but now it is apparently logically
950 * consistent and very flexible. F.e. as by-product it allows
951 * to co-exists in peace independent exterior and interior
952 * routing processes.
953 *
954 * Normally it looks as following.
955 *
956 * {universe prefix} -> (gw, oif) [scope link]
957 * |
958 * |-> {link prefix} -> (gw, oif) [scope local]
959 * |
960 * |-> {local prefix} (terminal node)
961 */
962 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
963 u8 scope, struct netlink_ext_ack *extack)
964 {
965 struct net_device *dev;
966 struct fib_result res;
967 int err = 0;
968
969 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
970 unsigned int addr_type;
971
972 if (scope >= RT_SCOPE_LINK) {
973 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
974 return -EINVAL;
975 }
976 dev = __dev_get_by_index(net, nh->fib_nh_oif);
977 if (!dev) {
978 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
979 return -ENODEV;
980 }
981 if (!(dev->flags & IFF_UP)) {
982 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
983 return -ENETDOWN;
984 }
985 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
986 if (addr_type != RTN_UNICAST) {
987 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
988 return -EINVAL;
989 }
990 if (!netif_carrier_ok(dev))
991 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
992 nh->fib_nh_dev = dev;
993 dev_hold(dev);
994 nh->fib_nh_scope = RT_SCOPE_LINK;
995 return 0;
996 }
997 rcu_read_lock();
998 {
999 struct fib_table *tbl = NULL;
1000 struct flowi4 fl4 = {
1001 .daddr = nh->fib_nh_gw4,
1002 .flowi4_scope = scope + 1,
1003 .flowi4_oif = nh->fib_nh_oif,
1004 .flowi4_iif = LOOPBACK_IFINDEX,
1005 };
1006
1007 /* It is not necessary, but requires a bit of thinking */
1008 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1009 fl4.flowi4_scope = RT_SCOPE_LINK;
1010
1011 if (table)
1012 tbl = fib_get_table(net, table);
1013
1014 if (tbl)
1015 err = fib_table_lookup(tbl, &fl4, &res,
1016 FIB_LOOKUP_IGNORE_LINKSTATE |
1017 FIB_LOOKUP_NOREF);
1018
1019 /* on error or if no table given do full lookup. This
1020 * is needed for example when nexthops are in the local
1021 * table rather than the given table
1022 */
1023 if (!tbl || err) {
1024 err = fib_lookup(net, &fl4, &res,
1025 FIB_LOOKUP_IGNORE_LINKSTATE);
1026 }
1027
1028 if (err) {
1029 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1030 goto out;
1031 }
1032 }
1033
1034 err = -EINVAL;
1035 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1036 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1037 goto out;
1038 }
1039 nh->fib_nh_scope = res.scope;
1040 nh->fib_nh_oif = FIB_RES_OIF(res);
1041 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1042 if (!dev) {
1043 NL_SET_ERR_MSG(extack,
1044 "No egress device for nexthop gateway");
1045 goto out;
1046 }
1047 dev_hold(dev);
1048 if (!netif_carrier_ok(dev))
1049 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1050 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1051 out:
1052 rcu_read_unlock();
1053 return err;
1054 }
1055
1056 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1057 struct netlink_ext_ack *extack)
1058 {
1059 struct in_device *in_dev;
1060 int err;
1061
1062 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1063 NL_SET_ERR_MSG(extack,
1064 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1065 return -EINVAL;
1066 }
1067
1068 rcu_read_lock();
1069
1070 err = -ENODEV;
1071 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1072 if (!in_dev)
1073 goto out;
1074 err = -ENETDOWN;
1075 if (!(in_dev->dev->flags & IFF_UP)) {
1076 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1077 goto out;
1078 }
1079
1080 nh->fib_nh_dev = in_dev->dev;
1081 dev_hold(nh->fib_nh_dev);
1082 nh->fib_nh_scope = RT_SCOPE_HOST;
1083 if (!netif_carrier_ok(nh->fib_nh_dev))
1084 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1085 err = 0;
1086 out:
1087 rcu_read_unlock();
1088 return err;
1089 }
1090
1091 static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh,
1092 struct netlink_ext_ack *extack)
1093 {
1094 struct net *net = cfg->fc_nlinfo.nl_net;
1095 u32 table = cfg->fc_table;
1096 int err;
1097
1098 if (nh->fib_nh_gw_family == AF_INET)
1099 err = fib_check_nh_v4_gw(net, nh, table, cfg->fc_scope, extack);
1100 else if (nh->fib_nh_gw_family == AF_INET6)
1101 err = fib_check_nh_v6_gw(net, nh, table, extack);
1102 else
1103 err = fib_check_nh_nongw(net, nh, extack);
1104
1105 return err;
1106 }
1107
1108 static inline unsigned int fib_laddr_hashfn(__be32 val)
1109 {
1110 unsigned int mask = (fib_info_hash_size - 1);
1111
1112 return ((__force u32)val ^
1113 ((__force u32)val >> 7) ^
1114 ((__force u32)val >> 14)) & mask;
1115 }
1116
1117 static struct hlist_head *fib_info_hash_alloc(int bytes)
1118 {
1119 if (bytes <= PAGE_SIZE)
1120 return kzalloc(bytes, GFP_KERNEL);
1121 else
1122 return (struct hlist_head *)
1123 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1124 get_order(bytes));
1125 }
1126
1127 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1128 {
1129 if (!hash)
1130 return;
1131
1132 if (bytes <= PAGE_SIZE)
1133 kfree(hash);
1134 else
1135 free_pages((unsigned long) hash, get_order(bytes));
1136 }
1137
1138 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1139 struct hlist_head *new_laddrhash,
1140 unsigned int new_size)
1141 {
1142 struct hlist_head *old_info_hash, *old_laddrhash;
1143 unsigned int old_size = fib_info_hash_size;
1144 unsigned int i, bytes;
1145
1146 spin_lock_bh(&fib_info_lock);
1147 old_info_hash = fib_info_hash;
1148 old_laddrhash = fib_info_laddrhash;
1149 fib_info_hash_size = new_size;
1150
1151 for (i = 0; i < old_size; i++) {
1152 struct hlist_head *head = &fib_info_hash[i];
1153 struct hlist_node *n;
1154 struct fib_info *fi;
1155
1156 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1157 struct hlist_head *dest;
1158 unsigned int new_hash;
1159
1160 new_hash = fib_info_hashfn(fi);
1161 dest = &new_info_hash[new_hash];
1162 hlist_add_head(&fi->fib_hash, dest);
1163 }
1164 }
1165 fib_info_hash = new_info_hash;
1166
1167 for (i = 0; i < old_size; i++) {
1168 struct hlist_head *lhead = &fib_info_laddrhash[i];
1169 struct hlist_node *n;
1170 struct fib_info *fi;
1171
1172 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1173 struct hlist_head *ldest;
1174 unsigned int new_hash;
1175
1176 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1177 ldest = &new_laddrhash[new_hash];
1178 hlist_add_head(&fi->fib_lhash, ldest);
1179 }
1180 }
1181 fib_info_laddrhash = new_laddrhash;
1182
1183 spin_unlock_bh(&fib_info_lock);
1184
1185 bytes = old_size * sizeof(struct hlist_head *);
1186 fib_info_hash_free(old_info_hash, bytes);
1187 fib_info_hash_free(old_laddrhash, bytes);
1188 }
1189
1190 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
1191 {
1192 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev,
1193 nh->fib_nh_gw4,
1194 nh->nh_parent->fib_scope);
1195 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1196
1197 return nh->nh_saddr;
1198 }
1199
1200 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1201 {
1202 struct fib_nh_common *nhc = res->nhc;
1203 struct fib_nh *nh;
1204
1205 if (res->fi->fib_prefsrc)
1206 return res->fi->fib_prefsrc;
1207
1208 nh = container_of(nhc, struct fib_nh, nh_common);
1209 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1210 return nh->nh_saddr;
1211
1212 return fib_info_update_nh_saddr(net, nh);
1213 }
1214
1215 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1216 {
1217 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1218 fib_prefsrc != cfg->fc_dst) {
1219 u32 tb_id = cfg->fc_table;
1220 int rc;
1221
1222 if (tb_id == RT_TABLE_MAIN)
1223 tb_id = RT_TABLE_LOCAL;
1224
1225 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1226 fib_prefsrc, tb_id);
1227
1228 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1229 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1230 fib_prefsrc, RT_TABLE_LOCAL);
1231 }
1232
1233 if (rc != RTN_LOCAL)
1234 return false;
1235 }
1236 return true;
1237 }
1238
1239 struct fib_info *fib_create_info(struct fib_config *cfg,
1240 struct netlink_ext_ack *extack)
1241 {
1242 int err;
1243 struct fib_info *fi = NULL;
1244 struct fib_info *ofi;
1245 int nhs = 1;
1246 struct net *net = cfg->fc_nlinfo.nl_net;
1247
1248 if (cfg->fc_type > RTN_MAX)
1249 goto err_inval;
1250
1251 /* Fast check to catch the most weird cases */
1252 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1253 NL_SET_ERR_MSG(extack, "Invalid scope");
1254 goto err_inval;
1255 }
1256
1257 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1258 NL_SET_ERR_MSG(extack,
1259 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1260 goto err_inval;
1261 }
1262
1263 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1264 if (cfg->fc_mp) {
1265 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1266 if (nhs == 0)
1267 goto err_inval;
1268 }
1269 #endif
1270
1271 err = -ENOBUFS;
1272 if (fib_info_cnt >= fib_info_hash_size) {
1273 unsigned int new_size = fib_info_hash_size << 1;
1274 struct hlist_head *new_info_hash;
1275 struct hlist_head *new_laddrhash;
1276 unsigned int bytes;
1277
1278 if (!new_size)
1279 new_size = 16;
1280 bytes = new_size * sizeof(struct hlist_head *);
1281 new_info_hash = fib_info_hash_alloc(bytes);
1282 new_laddrhash = fib_info_hash_alloc(bytes);
1283 if (!new_info_hash || !new_laddrhash) {
1284 fib_info_hash_free(new_info_hash, bytes);
1285 fib_info_hash_free(new_laddrhash, bytes);
1286 } else
1287 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1288
1289 if (!fib_info_hash_size)
1290 goto failure;
1291 }
1292
1293 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1294 if (!fi)
1295 goto failure;
1296 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1297 cfg->fc_mx_len, extack);
1298 if (unlikely(IS_ERR(fi->fib_metrics))) {
1299 err = PTR_ERR(fi->fib_metrics);
1300 kfree(fi);
1301 return ERR_PTR(err);
1302 }
1303
1304 fib_info_cnt++;
1305 fi->fib_net = net;
1306 fi->fib_protocol = cfg->fc_protocol;
1307 fi->fib_scope = cfg->fc_scope;
1308 fi->fib_flags = cfg->fc_flags;
1309 fi->fib_priority = cfg->fc_priority;
1310 fi->fib_prefsrc = cfg->fc_prefsrc;
1311 fi->fib_type = cfg->fc_type;
1312 fi->fib_tb_id = cfg->fc_table;
1313
1314 fi->fib_nhs = nhs;
1315 change_nexthops(fi) {
1316 nexthop_nh->nh_parent = fi;
1317 } endfor_nexthops(fi)
1318
1319 if (cfg->fc_mp)
1320 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1321 else
1322 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1323
1324 if (err != 0)
1325 goto failure;
1326
1327 if (fib_props[cfg->fc_type].error) {
1328 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1329 NL_SET_ERR_MSG(extack,
1330 "Gateway, device and multipath can not be specified for this route type");
1331 goto err_inval;
1332 }
1333 goto link_it;
1334 } else {
1335 switch (cfg->fc_type) {
1336 case RTN_UNICAST:
1337 case RTN_LOCAL:
1338 case RTN_BROADCAST:
1339 case RTN_ANYCAST:
1340 case RTN_MULTICAST:
1341 break;
1342 default:
1343 NL_SET_ERR_MSG(extack, "Invalid route type");
1344 goto err_inval;
1345 }
1346 }
1347
1348 if (cfg->fc_scope > RT_SCOPE_HOST) {
1349 NL_SET_ERR_MSG(extack, "Invalid scope");
1350 goto err_inval;
1351 }
1352
1353 if (cfg->fc_scope == RT_SCOPE_HOST) {
1354 struct fib_nh *nh = fi->fib_nh;
1355
1356 /* Local address is added. */
1357 if (nhs != 1) {
1358 NL_SET_ERR_MSG(extack,
1359 "Route with host scope can not have multiple nexthops");
1360 goto err_inval;
1361 }
1362 if (nh->fib_nh_gw_family) {
1363 NL_SET_ERR_MSG(extack,
1364 "Route with host scope can not have a gateway");
1365 goto err_inval;
1366 }
1367 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1368 nh->fib_nh_dev = dev_get_by_index(net, fi->fib_nh->fib_nh_oif);
1369 err = -ENODEV;
1370 if (!nh->fib_nh_dev)
1371 goto failure;
1372 } else {
1373 int linkdown = 0;
1374
1375 change_nexthops(fi) {
1376 err = fib_check_nh(cfg, nexthop_nh, extack);
1377 if (err != 0)
1378 goto failure;
1379 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1380 linkdown++;
1381 } endfor_nexthops(fi)
1382 if (linkdown == fi->fib_nhs)
1383 fi->fib_flags |= RTNH_F_LINKDOWN;
1384 }
1385
1386 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1387 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1388 goto err_inval;
1389 }
1390
1391 change_nexthops(fi) {
1392 fib_info_update_nh_saddr(net, nexthop_nh);
1393 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1394 fi->fib_nh_is_v6 = true;
1395 } endfor_nexthops(fi)
1396
1397 fib_rebalance(fi);
1398
1399 link_it:
1400 ofi = fib_find_info(fi);
1401 if (ofi) {
1402 fi->fib_dead = 1;
1403 free_fib_info(fi);
1404 ofi->fib_treeref++;
1405 return ofi;
1406 }
1407
1408 fi->fib_treeref++;
1409 refcount_set(&fi->fib_clntref, 1);
1410 spin_lock_bh(&fib_info_lock);
1411 hlist_add_head(&fi->fib_hash,
1412 &fib_info_hash[fib_info_hashfn(fi)]);
1413 if (fi->fib_prefsrc) {
1414 struct hlist_head *head;
1415
1416 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1417 hlist_add_head(&fi->fib_lhash, head);
1418 }
1419 change_nexthops(fi) {
1420 struct hlist_head *head;
1421 unsigned int hash;
1422
1423 if (!nexthop_nh->fib_nh_dev)
1424 continue;
1425 hash = fib_devindex_hashfn(nexthop_nh->fib_nh_dev->ifindex);
1426 head = &fib_info_devhash[hash];
1427 hlist_add_head(&nexthop_nh->nh_hash, head);
1428 } endfor_nexthops(fi)
1429 spin_unlock_bh(&fib_info_lock);
1430 return fi;
1431
1432 err_inval:
1433 err = -EINVAL;
1434
1435 failure:
1436 if (fi) {
1437 fi->fib_dead = 1;
1438 free_fib_info(fi);
1439 }
1440
1441 return ERR_PTR(err);
1442 }
1443
1444 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1445 unsigned char *flags, bool skip_oif)
1446 {
1447 if (nhc->nhc_flags & RTNH_F_DEAD)
1448 *flags |= RTNH_F_DEAD;
1449
1450 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1451 *flags |= RTNH_F_LINKDOWN;
1452
1453 rcu_read_lock();
1454 switch (nhc->nhc_family) {
1455 case AF_INET:
1456 if (ip_ignore_linkdown(nhc->nhc_dev))
1457 *flags |= RTNH_F_DEAD;
1458 break;
1459 case AF_INET6:
1460 if (ip6_ignore_linkdown(nhc->nhc_dev))
1461 *flags |= RTNH_F_DEAD;
1462 break;
1463 }
1464 rcu_read_unlock();
1465 }
1466
1467 switch (nhc->nhc_gw_family) {
1468 case AF_INET:
1469 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1470 goto nla_put_failure;
1471 break;
1472 case AF_INET6:
1473 /* if gateway family does not match nexthop family
1474 * gateway is encoded as RTA_VIA
1475 */
1476 if (nhc->nhc_gw_family != nhc->nhc_family) {
1477 int alen = sizeof(struct in6_addr);
1478 struct nlattr *nla;
1479 struct rtvia *via;
1480
1481 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1482 if (!nla)
1483 goto nla_put_failure;
1484
1485 via = nla_data(nla);
1486 via->rtvia_family = AF_INET6;
1487 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1488 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1489 &nhc->nhc_gw.ipv6) < 0) {
1490 goto nla_put_failure;
1491 }
1492 break;
1493 }
1494
1495 *flags |= (nhc->nhc_flags & RTNH_F_ONLINK);
1496 if (nhc->nhc_flags & RTNH_F_OFFLOAD)
1497 *flags |= RTNH_F_OFFLOAD;
1498
1499 if (!skip_oif && nhc->nhc_dev &&
1500 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1501 goto nla_put_failure;
1502
1503 if (nhc->nhc_lwtstate &&
1504 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1505 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1506 goto nla_put_failure;
1507
1508 return 0;
1509
1510 nla_put_failure:
1511 return -EMSGSIZE;
1512 }
1513 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1514
1515 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
1516 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1517 int nh_weight)
1518 {
1519 const struct net_device *dev = nhc->nhc_dev;
1520 struct rtnexthop *rtnh;
1521 unsigned char flags = 0;
1522
1523 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1524 if (!rtnh)
1525 goto nla_put_failure;
1526
1527 rtnh->rtnh_hops = nh_weight - 1;
1528 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1529
1530 if (fib_nexthop_info(skb, nhc, &flags, true) < 0)
1531 goto nla_put_failure;
1532
1533 rtnh->rtnh_flags = flags;
1534
1535 /* length of rtnetlink header + attributes */
1536 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1537
1538 return 0;
1539
1540 nla_put_failure:
1541 return -EMSGSIZE;
1542 }
1543 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1544 #endif
1545
1546 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1547 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1548 {
1549 struct nlattr *mp;
1550
1551 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1552 if (!mp)
1553 goto nla_put_failure;
1554
1555 for_nexthops(fi) {
1556 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight) < 0)
1557 goto nla_put_failure;
1558 #ifdef CONFIG_IP_ROUTE_CLASSID
1559 if (nh->nh_tclassid &&
1560 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1561 goto nla_put_failure;
1562 #endif
1563 } endfor_nexthops(fi);
1564
1565 nla_nest_end(skb, mp);
1566
1567 return 0;
1568
1569 nla_put_failure:
1570 return -EMSGSIZE;
1571 }
1572 #else
1573 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1574 {
1575 return 0;
1576 }
1577 #endif
1578
1579 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1580 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1581 struct fib_info *fi, unsigned int flags)
1582 {
1583 struct nlmsghdr *nlh;
1584 struct rtmsg *rtm;
1585
1586 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1587 if (!nlh)
1588 return -EMSGSIZE;
1589
1590 rtm = nlmsg_data(nlh);
1591 rtm->rtm_family = AF_INET;
1592 rtm->rtm_dst_len = dst_len;
1593 rtm->rtm_src_len = 0;
1594 rtm->rtm_tos = tos;
1595 if (tb_id < 256)
1596 rtm->rtm_table = tb_id;
1597 else
1598 rtm->rtm_table = RT_TABLE_COMPAT;
1599 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1600 goto nla_put_failure;
1601 rtm->rtm_type = type;
1602 rtm->rtm_flags = fi->fib_flags;
1603 rtm->rtm_scope = fi->fib_scope;
1604 rtm->rtm_protocol = fi->fib_protocol;
1605
1606 if (rtm->rtm_dst_len &&
1607 nla_put_in_addr(skb, RTA_DST, dst))
1608 goto nla_put_failure;
1609 if (fi->fib_priority &&
1610 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1611 goto nla_put_failure;
1612 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1613 goto nla_put_failure;
1614
1615 if (fi->fib_prefsrc &&
1616 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1617 goto nla_put_failure;
1618 if (fi->fib_nhs == 1) {
1619 struct fib_nh *nh = &fi->fib_nh[0];
1620 unsigned char flags = 0;
1621
1622 if (fib_nexthop_info(skb, &nh->nh_common, &flags, false) < 0)
1623 goto nla_put_failure;
1624
1625 rtm->rtm_flags = flags;
1626 #ifdef CONFIG_IP_ROUTE_CLASSID
1627 if (nh->nh_tclassid &&
1628 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1629 goto nla_put_failure;
1630 #endif
1631 } else {
1632 if (fib_add_multipath(skb, fi) < 0)
1633 goto nla_put_failure;
1634 }
1635
1636 nlmsg_end(skb, nlh);
1637 return 0;
1638
1639 nla_put_failure:
1640 nlmsg_cancel(skb, nlh);
1641 return -EMSGSIZE;
1642 }
1643
1644 /*
1645 * Update FIB if:
1646 * - local address disappeared -> we must delete all the entries
1647 * referring to it.
1648 * - device went down -> we must shutdown all nexthops going via it.
1649 */
1650 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1651 {
1652 int ret = 0;
1653 unsigned int hash = fib_laddr_hashfn(local);
1654 struct hlist_head *head = &fib_info_laddrhash[hash];
1655 struct net *net = dev_net(dev);
1656 int tb_id = l3mdev_fib_table(dev);
1657 struct fib_info *fi;
1658
1659 if (!fib_info_laddrhash || local == 0)
1660 return 0;
1661
1662 hlist_for_each_entry(fi, head, fib_lhash) {
1663 if (!net_eq(fi->fib_net, net) ||
1664 fi->fib_tb_id != tb_id)
1665 continue;
1666 if (fi->fib_prefsrc == local) {
1667 fi->fib_flags |= RTNH_F_DEAD;
1668 ret++;
1669 }
1670 }
1671 return ret;
1672 }
1673
1674 static int call_fib_nh_notifiers(struct fib_nh *nh,
1675 enum fib_event_type event_type)
1676 {
1677 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1678 struct fib_nh_notifier_info info = {
1679 .fib_nh = nh,
1680 };
1681
1682 switch (event_type) {
1683 case FIB_EVENT_NH_ADD:
1684 if (nh->fib_nh_flags & RTNH_F_DEAD)
1685 break;
1686 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1687 break;
1688 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1689 &info.info);
1690 case FIB_EVENT_NH_DEL:
1691 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1692 (nh->fib_nh_flags & RTNH_F_DEAD))
1693 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1694 event_type, &info.info);
1695 default:
1696 break;
1697 }
1698
1699 return NOTIFY_DONE;
1700 }
1701
1702 /* Update the PMTU of exceptions when:
1703 * - the new MTU of the first hop becomes smaller than the PMTU
1704 * - the old MTU was the same as the PMTU, and it limited discovery of
1705 * larger MTUs on the path. With that limit raised, we can now
1706 * discover larger MTUs
1707 * A special case is locked exceptions, for which the PMTU is smaller
1708 * than the minimal accepted PMTU:
1709 * - if the new MTU is greater than the PMTU, don't make any change
1710 * - otherwise, unlock and set PMTU
1711 */
1712 static void nh_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1713 {
1714 struct fnhe_hash_bucket *bucket;
1715 int i;
1716
1717 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1718 if (!bucket)
1719 return;
1720
1721 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1722 struct fib_nh_exception *fnhe;
1723
1724 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1725 fnhe;
1726 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1727 if (fnhe->fnhe_mtu_locked) {
1728 if (new <= fnhe->fnhe_pmtu) {
1729 fnhe->fnhe_pmtu = new;
1730 fnhe->fnhe_mtu_locked = false;
1731 }
1732 } else if (new < fnhe->fnhe_pmtu ||
1733 orig == fnhe->fnhe_pmtu) {
1734 fnhe->fnhe_pmtu = new;
1735 }
1736 }
1737 }
1738 }
1739
1740 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1741 {
1742 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1743 struct hlist_head *head = &fib_info_devhash[hash];
1744 struct fib_nh *nh;
1745
1746 hlist_for_each_entry(nh, head, nh_hash) {
1747 if (nh->fib_nh_dev == dev)
1748 nh_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1749 }
1750 }
1751
1752 /* Event force Flags Description
1753 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1754 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1755 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1756 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1757 */
1758 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1759 {
1760 int ret = 0;
1761 int scope = RT_SCOPE_NOWHERE;
1762 struct fib_info *prev_fi = NULL;
1763 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1764 struct hlist_head *head = &fib_info_devhash[hash];
1765 struct fib_nh *nh;
1766
1767 if (force)
1768 scope = -1;
1769
1770 hlist_for_each_entry(nh, head, nh_hash) {
1771 struct fib_info *fi = nh->nh_parent;
1772 int dead;
1773
1774 BUG_ON(!fi->fib_nhs);
1775 if (nh->fib_nh_dev != dev || fi == prev_fi)
1776 continue;
1777 prev_fi = fi;
1778 dead = 0;
1779 change_nexthops(fi) {
1780 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
1781 dead++;
1782 else if (nexthop_nh->fib_nh_dev == dev &&
1783 nexthop_nh->fib_nh_scope != scope) {
1784 switch (event) {
1785 case NETDEV_DOWN:
1786 case NETDEV_UNREGISTER:
1787 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
1788 /* fall through */
1789 case NETDEV_CHANGE:
1790 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1791 break;
1792 }
1793 call_fib_nh_notifiers(nexthop_nh,
1794 FIB_EVENT_NH_DEL);
1795 dead++;
1796 }
1797 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1798 if (event == NETDEV_UNREGISTER &&
1799 nexthop_nh->fib_nh_dev == dev) {
1800 dead = fi->fib_nhs;
1801 break;
1802 }
1803 #endif
1804 } endfor_nexthops(fi)
1805 if (dead == fi->fib_nhs) {
1806 switch (event) {
1807 case NETDEV_DOWN:
1808 case NETDEV_UNREGISTER:
1809 fi->fib_flags |= RTNH_F_DEAD;
1810 /* fall through */
1811 case NETDEV_CHANGE:
1812 fi->fib_flags |= RTNH_F_LINKDOWN;
1813 break;
1814 }
1815 ret++;
1816 }
1817
1818 fib_rebalance(fi);
1819 }
1820
1821 return ret;
1822 }
1823
1824 /* Must be invoked inside of an RCU protected region. */
1825 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1826 {
1827 struct fib_info *fi = NULL, *last_resort = NULL;
1828 struct hlist_head *fa_head = res->fa_head;
1829 struct fib_table *tb = res->table;
1830 u8 slen = 32 - res->prefixlen;
1831 int order = -1, last_idx = -1;
1832 struct fib_alias *fa, *fa1 = NULL;
1833 u32 last_prio = res->fi->fib_priority;
1834 u8 last_tos = 0;
1835
1836 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1837 struct fib_info *next_fi = fa->fa_info;
1838
1839 if (fa->fa_slen != slen)
1840 continue;
1841 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1842 continue;
1843 if (fa->tb_id != tb->tb_id)
1844 continue;
1845 if (next_fi->fib_priority > last_prio &&
1846 fa->fa_tos == last_tos) {
1847 if (last_tos)
1848 continue;
1849 break;
1850 }
1851 if (next_fi->fib_flags & RTNH_F_DEAD)
1852 continue;
1853 last_tos = fa->fa_tos;
1854 last_prio = next_fi->fib_priority;
1855
1856 if (next_fi->fib_scope != res->scope ||
1857 fa->fa_type != RTN_UNICAST)
1858 continue;
1859 if (!next_fi->fib_nh[0].fib_nh_gw4 ||
1860 next_fi->fib_nh[0].fib_nh_scope != RT_SCOPE_LINK)
1861 continue;
1862
1863 fib_alias_accessed(fa);
1864
1865 if (!fi) {
1866 if (next_fi != res->fi)
1867 break;
1868 fa1 = fa;
1869 } else if (!fib_detect_death(fi, order, &last_resort,
1870 &last_idx, fa1->fa_default)) {
1871 fib_result_assign(res, fi);
1872 fa1->fa_default = order;
1873 goto out;
1874 }
1875 fi = next_fi;
1876 order++;
1877 }
1878
1879 if (order <= 0 || !fi) {
1880 if (fa1)
1881 fa1->fa_default = -1;
1882 goto out;
1883 }
1884
1885 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1886 fa1->fa_default)) {
1887 fib_result_assign(res, fi);
1888 fa1->fa_default = order;
1889 goto out;
1890 }
1891
1892 if (last_idx >= 0)
1893 fib_result_assign(res, last_resort);
1894 fa1->fa_default = last_idx;
1895 out:
1896 return;
1897 }
1898
1899 /*
1900 * Dead device goes up. We wake up dead nexthops.
1901 * It takes sense only on multipath routes.
1902 */
1903 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
1904 {
1905 struct fib_info *prev_fi;
1906 unsigned int hash;
1907 struct hlist_head *head;
1908 struct fib_nh *nh;
1909 int ret;
1910
1911 if (!(dev->flags & IFF_UP))
1912 return 0;
1913
1914 if (nh_flags & RTNH_F_DEAD) {
1915 unsigned int flags = dev_get_flags(dev);
1916
1917 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1918 nh_flags |= RTNH_F_LINKDOWN;
1919 }
1920
1921 prev_fi = NULL;
1922 hash = fib_devindex_hashfn(dev->ifindex);
1923 head = &fib_info_devhash[hash];
1924 ret = 0;
1925
1926 hlist_for_each_entry(nh, head, nh_hash) {
1927 struct fib_info *fi = nh->nh_parent;
1928 int alive;
1929
1930 BUG_ON(!fi->fib_nhs);
1931 if (nh->fib_nh_dev != dev || fi == prev_fi)
1932 continue;
1933
1934 prev_fi = fi;
1935 alive = 0;
1936 change_nexthops(fi) {
1937 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
1938 alive++;
1939 continue;
1940 }
1941 if (!nexthop_nh->fib_nh_dev ||
1942 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
1943 continue;
1944 if (nexthop_nh->fib_nh_dev != dev ||
1945 !__in_dev_get_rtnl(dev))
1946 continue;
1947 alive++;
1948 nexthop_nh->fib_nh_flags &= ~nh_flags;
1949 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1950 } endfor_nexthops(fi)
1951
1952 if (alive > 0) {
1953 fi->fib_flags &= ~nh_flags;
1954 ret++;
1955 }
1956
1957 fib_rebalance(fi);
1958 }
1959
1960 return ret;
1961 }
1962
1963 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1964 static bool fib_good_nh(const struct fib_nh *nh)
1965 {
1966 int state = NUD_REACHABLE;
1967
1968 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
1969 struct neighbour *n;
1970
1971 rcu_read_lock_bh();
1972
1973 if (likely(nh->fib_nh_gw_family == AF_INET))
1974 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
1975 (__force u32)nh->fib_nh_gw4);
1976 else if (nh->fib_nh_gw_family == AF_INET6)
1977 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
1978 &nh->fib_nh_gw6);
1979 else
1980 n = NULL;
1981 if (n)
1982 state = n->nud_state;
1983
1984 rcu_read_unlock_bh();
1985 }
1986
1987 return !!(state & NUD_VALID);
1988 }
1989
1990 void fib_select_multipath(struct fib_result *res, int hash)
1991 {
1992 struct fib_info *fi = res->fi;
1993 struct net *net = fi->fib_net;
1994 bool first = false;
1995
1996 change_nexthops(fi) {
1997 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
1998 if (!fib_good_nh(nexthop_nh))
1999 continue;
2000 if (!first) {
2001 res->nh_sel = nhsel;
2002 res->nhc = &nexthop_nh->nh_common;
2003 first = true;
2004 }
2005 }
2006
2007 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2008 continue;
2009
2010 res->nh_sel = nhsel;
2011 res->nhc = &nexthop_nh->nh_common;
2012 return;
2013 } endfor_nexthops(fi);
2014 }
2015 #endif
2016
2017 void fib_select_path(struct net *net, struct fib_result *res,
2018 struct flowi4 *fl4, const struct sk_buff *skb)
2019 {
2020 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2021 goto check_saddr;
2022
2023 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2024 if (res->fi->fib_nhs > 1) {
2025 int h = fib_multipath_hash(net, fl4, skb, NULL);
2026
2027 fib_select_multipath(res, h);
2028 }
2029 else
2030 #endif
2031 if (!res->prefixlen &&
2032 res->table->tb_num_default > 1 &&
2033 res->type == RTN_UNICAST)
2034 fib_select_default(fl4, res);
2035
2036 check_saddr:
2037 if (!fl4->saddr)
2038 fl4->saddr = fib_result_prefsrc(net, res);
2039 }
Mirror of linux-2.6-arm at arm.linux.org.uk