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