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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
51static DEFINE_SPINLOCK(fib_info_lock);
52static struct hlist_head *fib_info_hash;
53static struct hlist_head *fib_info_laddrhash;
54static unsigned int fib_info_hash_size;
55static unsigned int fib_info_cnt;
56
57#define DEVINDEX_HASHBITS 8
58#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
59static 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
93const 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
144static 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
160static 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
188static 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 */
208static 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
228void 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}
243EXPORT_SYMBOL_GPL(free_fib_info);
244
245void 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
263static 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
285static 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
294static 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
309static 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 */
341int 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
365static 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
407void 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;
431errout:
432 if (err < 0)
433 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
434}
435
436static 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
464static 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
484static 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
552err_inval:
553 ret = -EINVAL;
554
555errout:
556 return ret;
557}
558
559static 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
610static 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
632int 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
696bool 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 val = nla_get_u32(nla);
721 }
722
723 fi_val = fi->fib_metrics->metrics[type - 1];
724 if (type == RTAX_FEATURES)
725 fi_val &= ~DST_FEATURE_ECN_CA;
726
727 if (fi_val != val)
728 return false;
729 }
730
731 return true;
732}
733
734
735/*
736 * Picture
737 * -------
738 *
739 * Semantics of nexthop is very messy by historical reasons.
740 * We have to take into account, that:
741 * a) gateway can be actually local interface address,
742 * so that gatewayed route is direct.
743 * b) gateway must be on-link address, possibly
744 * described not by an ifaddr, but also by a direct route.
745 * c) If both gateway and interface are specified, they should not
746 * contradict.
747 * d) If we use tunnel routes, gateway could be not on-link.
748 *
749 * Attempt to reconcile all of these (alas, self-contradictory) conditions
750 * results in pretty ugly and hairy code with obscure logic.
751 *
752 * I chose to generalized it instead, so that the size
753 * of code does not increase practically, but it becomes
754 * much more general.
755 * Every prefix is assigned a "scope" value: "host" is local address,
756 * "link" is direct route,
757 * [ ... "site" ... "interior" ... ]
758 * and "universe" is true gateway route with global meaning.
759 *
760 * Every prefix refers to a set of "nexthop"s (gw, oif),
761 * where gw must have narrower scope. This recursion stops
762 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
763 * which means that gw is forced to be on link.
764 *
765 * Code is still hairy, but now it is apparently logically
766 * consistent and very flexible. F.e. as by-product it allows
767 * to co-exists in peace independent exterior and interior
768 * routing processes.
769 *
770 * Normally it looks as following.
771 *
772 * {universe prefix} -> (gw, oif) [scope link]
773 * |
774 * |-> {link prefix} -> (gw, oif) [scope local]
775 * |
776 * |-> {local prefix} (terminal node)
777 */
778static int fib_check_nh(struct fib_config *cfg, struct fib_nh *nh,
779 struct netlink_ext_ack *extack)
780{
781 int err = 0;
782 struct net *net;
783 struct net_device *dev;
784
785 net = cfg->fc_nlinfo.nl_net;
786 if (nh->nh_gw) {
787 struct fib_result res;
788
789 if (nh->nh_flags & RTNH_F_ONLINK) {
790 unsigned int addr_type;
791
792 if (cfg->fc_scope >= RT_SCOPE_LINK) {
793 NL_SET_ERR_MSG(extack,
794 "Nexthop has invalid scope");
795 return -EINVAL;
796 }
797 dev = __dev_get_by_index(net, nh->nh_oif);
798 if (!dev)
799 return -ENODEV;
800 if (!(dev->flags & IFF_UP)) {
801 NL_SET_ERR_MSG(extack,
802 "Nexthop device is not up");
803 return -ENETDOWN;
804 }
805 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
806 if (addr_type != RTN_UNICAST) {
807 NL_SET_ERR_MSG(extack,
808 "Nexthop has invalid gateway");
809 return -EINVAL;
810 }
811 if (!netif_carrier_ok(dev))
812 nh->nh_flags |= RTNH_F_LINKDOWN;
813 nh->nh_dev = dev;
814 dev_hold(dev);
815 nh->nh_scope = RT_SCOPE_LINK;
816 return 0;
817 }
818 rcu_read_lock();
819 {
820 struct fib_table *tbl = NULL;
821 struct flowi4 fl4 = {
822 .daddr = nh->nh_gw,
823 .flowi4_scope = cfg->fc_scope + 1,
824 .flowi4_oif = nh->nh_oif,
825 .flowi4_iif = LOOPBACK_IFINDEX,
826 };
827
828 /* It is not necessary, but requires a bit of thinking */
829 if (fl4.flowi4_scope < RT_SCOPE_LINK)
830 fl4.flowi4_scope = RT_SCOPE_LINK;
831
832 if (cfg->fc_table)
833 tbl = fib_get_table(net, cfg->fc_table);
834
835 if (tbl)
836 err = fib_table_lookup(tbl, &fl4, &res,
837 FIB_LOOKUP_IGNORE_LINKSTATE |
838 FIB_LOOKUP_NOREF);
839
840 /* on error or if no table given do full lookup. This
841 * is needed for example when nexthops are in the local
842 * table rather than the given table
843 */
844 if (!tbl || err) {
845 err = fib_lookup(net, &fl4, &res,
846 FIB_LOOKUP_IGNORE_LINKSTATE);
847 }
848
849 if (err) {
850 NL_SET_ERR_MSG(extack,
851 "Nexthop has invalid gateway");
852 rcu_read_unlock();
853 return err;
854 }
855 }
856 err = -EINVAL;
857 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
858 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
859 goto out;
860 }
861 nh->nh_scope = res.scope;
862 nh->nh_oif = FIB_RES_OIF(res);
863 nh->nh_dev = dev = FIB_RES_DEV(res);
864 if (!dev) {
865 NL_SET_ERR_MSG(extack,
866 "No egress device for nexthop gateway");
867 goto out;
868 }
869 dev_hold(dev);
870 if (!netif_carrier_ok(dev))
871 nh->nh_flags |= RTNH_F_LINKDOWN;
872 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
873 } else {
874 struct in_device *in_dev;
875
876 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
877 NL_SET_ERR_MSG(extack,
878 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
879 return -EINVAL;
880 }
881 rcu_read_lock();
882 err = -ENODEV;
883 in_dev = inetdev_by_index(net, nh->nh_oif);
884 if (!in_dev)
885 goto out;
886 err = -ENETDOWN;
887 if (!(in_dev->dev->flags & IFF_UP)) {
888 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
889 goto out;
890 }
891 nh->nh_dev = in_dev->dev;
892 dev_hold(nh->nh_dev);
893 nh->nh_scope = RT_SCOPE_HOST;
894 if (!netif_carrier_ok(nh->nh_dev))
895 nh->nh_flags |= RTNH_F_LINKDOWN;
896 err = 0;
897 }
898out:
899 rcu_read_unlock();
900 return err;
901}
902
903static inline unsigned int fib_laddr_hashfn(__be32 val)
904{
905 unsigned int mask = (fib_info_hash_size - 1);
906
907 return ((__force u32)val ^
908 ((__force u32)val >> 7) ^
909 ((__force u32)val >> 14)) & mask;
910}
911
912static struct hlist_head *fib_info_hash_alloc(int bytes)
913{
914 if (bytes <= PAGE_SIZE)
915 return kzalloc(bytes, GFP_KERNEL);
916 else
917 return (struct hlist_head *)
918 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
919 get_order(bytes));
920}
921
922static void fib_info_hash_free(struct hlist_head *hash, int bytes)
923{
924 if (!hash)
925 return;
926
927 if (bytes <= PAGE_SIZE)
928 kfree(hash);
929 else
930 free_pages((unsigned long) hash, get_order(bytes));
931}
932
933static void fib_info_hash_move(struct hlist_head *new_info_hash,
934 struct hlist_head *new_laddrhash,
935 unsigned int new_size)
936{
937 struct hlist_head *old_info_hash, *old_laddrhash;
938 unsigned int old_size = fib_info_hash_size;
939 unsigned int i, bytes;
940
941 spin_lock_bh(&fib_info_lock);
942 old_info_hash = fib_info_hash;
943 old_laddrhash = fib_info_laddrhash;
944 fib_info_hash_size = new_size;
945
946 for (i = 0; i < old_size; i++) {
947 struct hlist_head *head = &fib_info_hash[i];
948 struct hlist_node *n;
949 struct fib_info *fi;
950
951 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
952 struct hlist_head *dest;
953 unsigned int new_hash;
954
955 new_hash = fib_info_hashfn(fi);
956 dest = &new_info_hash[new_hash];
957 hlist_add_head(&fi->fib_hash, dest);
958 }
959 }
960 fib_info_hash = new_info_hash;
961
962 for (i = 0; i < old_size; i++) {
963 struct hlist_head *lhead = &fib_info_laddrhash[i];
964 struct hlist_node *n;
965 struct fib_info *fi;
966
967 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
968 struct hlist_head *ldest;
969 unsigned int new_hash;
970
971 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
972 ldest = &new_laddrhash[new_hash];
973 hlist_add_head(&fi->fib_lhash, ldest);
974 }
975 }
976 fib_info_laddrhash = new_laddrhash;
977
978 spin_unlock_bh(&fib_info_lock);
979
980 bytes = old_size * sizeof(struct hlist_head *);
981 fib_info_hash_free(old_info_hash, bytes);
982 fib_info_hash_free(old_laddrhash, bytes);
983}
984
985__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
986{
987 nh->nh_saddr = inet_select_addr(nh->nh_dev,
988 nh->nh_gw,
989 nh->nh_parent->fib_scope);
990 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
991
992 return nh->nh_saddr;
993}
994
995static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
996{
997 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
998 fib_prefsrc != cfg->fc_dst) {
999 u32 tb_id = cfg->fc_table;
1000 int rc;
1001
1002 if (tb_id == RT_TABLE_MAIN)
1003 tb_id = RT_TABLE_LOCAL;
1004
1005 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1006 fib_prefsrc, tb_id);
1007
1008 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1009 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1010 fib_prefsrc, RT_TABLE_LOCAL);
1011 }
1012
1013 if (rc != RTN_LOCAL)
1014 return false;
1015 }
1016 return true;
1017}
1018
1019static int
1020fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
1021{
1022 bool ecn_ca = false;
1023 struct nlattr *nla;
1024 int remaining;
1025
1026 if (!cfg->fc_mx)
1027 return 0;
1028
1029 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1030 int type = nla_type(nla);
1031 u32 val;
1032
1033 if (!type)
1034 continue;
1035 if (type > RTAX_MAX)
1036 return -EINVAL;
1037
1038 if (type == RTAX_CC_ALGO) {
1039 char tmp[TCP_CA_NAME_MAX];
1040
1041 nla_strlcpy(tmp, nla, sizeof(tmp));
1042 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1043 if (val == TCP_CA_UNSPEC)
1044 return -EINVAL;
1045 } else {
1046 val = nla_get_u32(nla);
1047 }
1048 if (type == RTAX_ADVMSS && val > 65535 - 40)
1049 val = 65535 - 40;
1050 if (type == RTAX_MTU && val > 65535 - 15)
1051 val = 65535 - 15;
1052 if (type == RTAX_HOPLIMIT && val > 255)
1053 val = 255;
1054 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
1055 return -EINVAL;
1056 fi->fib_metrics->metrics[type - 1] = val;
1057 }
1058
1059 if (ecn_ca)
1060 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
1061
1062 return 0;
1063}
1064
1065struct fib_info *fib_create_info(struct fib_config *cfg,
1066 struct netlink_ext_ack *extack)
1067{
1068 int err;
1069 struct fib_info *fi = NULL;
1070 struct fib_info *ofi;
1071 int nhs = 1;
1072 struct net *net = cfg->fc_nlinfo.nl_net;
1073
1074 if (cfg->fc_type > RTN_MAX)
1075 goto err_inval;
1076
1077 /* Fast check to catch the most weird cases */
1078 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1079 NL_SET_ERR_MSG(extack, "Invalid scope");
1080 goto err_inval;
1081 }
1082
1083 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1084 NL_SET_ERR_MSG(extack,
1085 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1086 goto err_inval;
1087 }
1088
1089#ifdef CONFIG_IP_ROUTE_MULTIPATH
1090 if (cfg->fc_mp) {
1091 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1092 if (nhs == 0)
1093 goto err_inval;
1094 }
1095#endif
1096
1097 err = -ENOBUFS;
1098 if (fib_info_cnt >= fib_info_hash_size) {
1099 unsigned int new_size = fib_info_hash_size << 1;
1100 struct hlist_head *new_info_hash;
1101 struct hlist_head *new_laddrhash;
1102 unsigned int bytes;
1103
1104 if (!new_size)
1105 new_size = 16;
1106 bytes = new_size * sizeof(struct hlist_head *);
1107 new_info_hash = fib_info_hash_alloc(bytes);
1108 new_laddrhash = fib_info_hash_alloc(bytes);
1109 if (!new_info_hash || !new_laddrhash) {
1110 fib_info_hash_free(new_info_hash, bytes);
1111 fib_info_hash_free(new_laddrhash, bytes);
1112 } else
1113 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1114
1115 if (!fib_info_hash_size)
1116 goto failure;
1117 }
1118
1119 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1120 if (!fi)
1121 goto failure;
1122 if (cfg->fc_mx) {
1123 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
1124 if (unlikely(!fi->fib_metrics)) {
1125 kfree(fi);
1126 return ERR_PTR(err);
1127 }
1128 refcount_set(&fi->fib_metrics->refcnt, 1);
1129 } else {
1130 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
1131 }
1132 fib_info_cnt++;
1133 fi->fib_net = net;
1134 fi->fib_protocol = cfg->fc_protocol;
1135 fi->fib_scope = cfg->fc_scope;
1136 fi->fib_flags = cfg->fc_flags;
1137 fi->fib_priority = cfg->fc_priority;
1138 fi->fib_prefsrc = cfg->fc_prefsrc;
1139 fi->fib_type = cfg->fc_type;
1140 fi->fib_tb_id = cfg->fc_table;
1141
1142 fi->fib_nhs = nhs;
1143 change_nexthops(fi) {
1144 nexthop_nh->nh_parent = fi;
1145 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1146 if (!nexthop_nh->nh_pcpu_rth_output)
1147 goto failure;
1148 } endfor_nexthops(fi)
1149
1150 err = fib_convert_metrics(fi, cfg);
1151 if (err)
1152 goto failure;
1153
1154 if (cfg->fc_mp) {
1155#ifdef CONFIG_IP_ROUTE_MULTIPATH
1156 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
1157 if (err != 0)
1158 goto failure;
1159 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
1160 NL_SET_ERR_MSG(extack,
1161 "Nexthop device index does not match RTA_OIF");
1162 goto err_inval;
1163 }
1164 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
1165 NL_SET_ERR_MSG(extack,
1166 "Nexthop gateway does not match RTA_GATEWAY");
1167 goto err_inval;
1168 }
1169#ifdef CONFIG_IP_ROUTE_CLASSID
1170 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
1171 NL_SET_ERR_MSG(extack,
1172 "Nexthop class id does not match RTA_FLOW");
1173 goto err_inval;
1174 }
1175#endif
1176#else
1177 NL_SET_ERR_MSG(extack,
1178 "Multipath support not enabled in kernel");
1179 goto err_inval;
1180#endif
1181 } else {
1182 struct fib_nh *nh = fi->fib_nh;
1183
1184 if (cfg->fc_encap) {
1185 struct lwtunnel_state *lwtstate;
1186
1187 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
1188 NL_SET_ERR_MSG(extack,
1189 "LWT encap type not specified");
1190 goto err_inval;
1191 }
1192 err = lwtunnel_build_state(cfg->fc_encap_type,
1193 cfg->fc_encap, AF_INET, cfg,
1194 &lwtstate, extack);
1195 if (err)
1196 goto failure;
1197
1198 nh->nh_lwtstate = lwtstate_get(lwtstate);
1199 }
1200 nh->nh_oif = cfg->fc_oif;
1201 nh->nh_gw = cfg->fc_gw;
1202 nh->nh_flags = cfg->fc_flags;
1203#ifdef CONFIG_IP_ROUTE_CLASSID
1204 nh->nh_tclassid = cfg->fc_flow;
1205 if (nh->nh_tclassid)
1206 fi->fib_net->ipv4.fib_num_tclassid_users++;
1207#endif
1208#ifdef CONFIG_IP_ROUTE_MULTIPATH
1209 nh->nh_weight = 1;
1210#endif
1211 }
1212
1213 if (fib_props[cfg->fc_type].error) {
1214 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) {
1215 NL_SET_ERR_MSG(extack,
1216 "Gateway, device and multipath can not be specified for this route type");
1217 goto err_inval;
1218 }
1219 goto link_it;
1220 } else {
1221 switch (cfg->fc_type) {
1222 case RTN_UNICAST:
1223 case RTN_LOCAL:
1224 case RTN_BROADCAST:
1225 case RTN_ANYCAST:
1226 case RTN_MULTICAST:
1227 break;
1228 default:
1229 NL_SET_ERR_MSG(extack, "Invalid route type");
1230 goto err_inval;
1231 }
1232 }
1233
1234 if (cfg->fc_scope > RT_SCOPE_HOST) {
1235 NL_SET_ERR_MSG(extack, "Invalid scope");
1236 goto err_inval;
1237 }
1238
1239 if (cfg->fc_scope == RT_SCOPE_HOST) {
1240 struct fib_nh *nh = fi->fib_nh;
1241
1242 /* Local address is added. */
1243 if (nhs != 1) {
1244 NL_SET_ERR_MSG(extack,
1245 "Route with host scope can not have multiple nexthops");
1246 goto err_inval;
1247 }
1248 if (nh->nh_gw) {
1249 NL_SET_ERR_MSG(extack,
1250 "Route with host scope can not have a gateway");
1251 goto err_inval;
1252 }
1253 nh->nh_scope = RT_SCOPE_NOWHERE;
1254 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1255 err = -ENODEV;
1256 if (!nh->nh_dev)
1257 goto failure;
1258 } else {
1259 int linkdown = 0;
1260
1261 change_nexthops(fi) {
1262 err = fib_check_nh(cfg, nexthop_nh, extack);
1263 if (err != 0)
1264 goto failure;
1265 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1266 linkdown++;
1267 } endfor_nexthops(fi)
1268 if (linkdown == fi->fib_nhs)
1269 fi->fib_flags |= RTNH_F_LINKDOWN;
1270 }
1271
1272 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1273 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1274 goto err_inval;
1275 }
1276
1277 change_nexthops(fi) {
1278 fib_info_update_nh_saddr(net, nexthop_nh);
1279 } endfor_nexthops(fi)
1280
1281 fib_rebalance(fi);
1282
1283link_it:
1284 ofi = fib_find_info(fi);
1285 if (ofi) {
1286 fi->fib_dead = 1;
1287 free_fib_info(fi);
1288 ofi->fib_treeref++;
1289 return ofi;
1290 }
1291
1292 fi->fib_treeref++;
1293 refcount_set(&fi->fib_clntref, 1);
1294 spin_lock_bh(&fib_info_lock);
1295 hlist_add_head(&fi->fib_hash,
1296 &fib_info_hash[fib_info_hashfn(fi)]);
1297 if (fi->fib_prefsrc) {
1298 struct hlist_head *head;
1299
1300 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1301 hlist_add_head(&fi->fib_lhash, head);
1302 }
1303 change_nexthops(fi) {
1304 struct hlist_head *head;
1305 unsigned int hash;
1306
1307 if (!nexthop_nh->nh_dev)
1308 continue;
1309 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1310 head = &fib_info_devhash[hash];
1311 hlist_add_head(&nexthop_nh->nh_hash, head);
1312 } endfor_nexthops(fi)
1313 spin_unlock_bh(&fib_info_lock);
1314 return fi;
1315
1316err_inval:
1317 err = -EINVAL;
1318
1319failure:
1320 if (fi) {
1321 fi->fib_dead = 1;
1322 free_fib_info(fi);
1323 }
1324
1325 return ERR_PTR(err);
1326}
1327
1328int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1329 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1330 struct fib_info *fi, unsigned int flags)
1331{
1332 struct nlmsghdr *nlh;
1333 struct rtmsg *rtm;
1334
1335 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1336 if (!nlh)
1337 return -EMSGSIZE;
1338
1339 rtm = nlmsg_data(nlh);
1340 rtm->rtm_family = AF_INET;
1341 rtm->rtm_dst_len = dst_len;
1342 rtm->rtm_src_len = 0;
1343 rtm->rtm_tos = tos;
1344 if (tb_id < 256)
1345 rtm->rtm_table = tb_id;
1346 else
1347 rtm->rtm_table = RT_TABLE_COMPAT;
1348 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1349 goto nla_put_failure;
1350 rtm->rtm_type = type;
1351 rtm->rtm_flags = fi->fib_flags;
1352 rtm->rtm_scope = fi->fib_scope;
1353 rtm->rtm_protocol = fi->fib_protocol;
1354
1355 if (rtm->rtm_dst_len &&
1356 nla_put_in_addr(skb, RTA_DST, dst))
1357 goto nla_put_failure;
1358 if (fi->fib_priority &&
1359 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1360 goto nla_put_failure;
1361 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1362 goto nla_put_failure;
1363
1364 if (fi->fib_prefsrc &&
1365 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1366 goto nla_put_failure;
1367 if (fi->fib_nhs == 1) {
1368 if (fi->fib_nh->nh_gw &&
1369 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1370 goto nla_put_failure;
1371 if (fi->fib_nh->nh_oif &&
1372 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1373 goto nla_put_failure;
1374 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1375 struct in_device *in_dev;
1376
1377 rcu_read_lock();
1378 in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev);
1379 if (in_dev &&
1380 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1381 rtm->rtm_flags |= RTNH_F_DEAD;
1382 rcu_read_unlock();
1383 }
1384 if (fi->fib_nh->nh_flags & RTNH_F_OFFLOAD)
1385 rtm->rtm_flags |= RTNH_F_OFFLOAD;
1386#ifdef CONFIG_IP_ROUTE_CLASSID
1387 if (fi->fib_nh[0].nh_tclassid &&
1388 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1389 goto nla_put_failure;
1390#endif
1391 if (fi->fib_nh->nh_lwtstate &&
1392 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1393 goto nla_put_failure;
1394 }
1395#ifdef CONFIG_IP_ROUTE_MULTIPATH
1396 if (fi->fib_nhs > 1) {
1397 struct rtnexthop *rtnh;
1398 struct nlattr *mp;
1399
1400 mp = nla_nest_start(skb, RTA_MULTIPATH);
1401 if (!mp)
1402 goto nla_put_failure;
1403
1404 for_nexthops(fi) {
1405 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1406 if (!rtnh)
1407 goto nla_put_failure;
1408
1409 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1410 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1411 struct in_device *in_dev;
1412
1413 rcu_read_lock();
1414 in_dev = __in_dev_get_rcu(nh->nh_dev);
1415 if (in_dev &&
1416 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1417 rtnh->rtnh_flags |= RTNH_F_DEAD;
1418 rcu_read_unlock();
1419 }
1420 rtnh->rtnh_hops = nh->nh_weight - 1;
1421 rtnh->rtnh_ifindex = nh->nh_oif;
1422
1423 if (nh->nh_gw &&
1424 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1425 goto nla_put_failure;
1426#ifdef CONFIG_IP_ROUTE_CLASSID
1427 if (nh->nh_tclassid &&
1428 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1429 goto nla_put_failure;
1430#endif
1431 if (nh->nh_lwtstate &&
1432 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1433 goto nla_put_failure;
1434
1435 /* length of rtnetlink header + attributes */
1436 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1437 } endfor_nexthops(fi);
1438
1439 nla_nest_end(skb, mp);
1440 }
1441#endif
1442 nlmsg_end(skb, nlh);
1443 return 0;
1444
1445nla_put_failure:
1446 nlmsg_cancel(skb, nlh);
1447 return -EMSGSIZE;
1448}
1449
1450/*
1451 * Update FIB if:
1452 * - local address disappeared -> we must delete all the entries
1453 * referring to it.
1454 * - device went down -> we must shutdown all nexthops going via it.
1455 */
1456int fib_sync_down_addr(struct net_device *dev, __be32 local)
1457{
1458 int ret = 0;
1459 unsigned int hash = fib_laddr_hashfn(local);
1460 struct hlist_head *head = &fib_info_laddrhash[hash];
1461 struct net *net = dev_net(dev);
1462 int tb_id = l3mdev_fib_table(dev);
1463 struct fib_info *fi;
1464
1465 if (!fib_info_laddrhash || local == 0)
1466 return 0;
1467
1468 hlist_for_each_entry(fi, head, fib_lhash) {
1469 if (!net_eq(fi->fib_net, net) ||
1470 fi->fib_tb_id != tb_id)
1471 continue;
1472 if (fi->fib_prefsrc == local) {
1473 fi->fib_flags |= RTNH_F_DEAD;
1474 ret++;
1475 }
1476 }
1477 return ret;
1478}
1479
1480static int call_fib_nh_notifiers(struct fib_nh *fib_nh,
1481 enum fib_event_type event_type)
1482{
1483 struct in_device *in_dev = __in_dev_get_rtnl(fib_nh->nh_dev);
1484 struct fib_nh_notifier_info info = {
1485 .fib_nh = fib_nh,
1486 };
1487
1488 switch (event_type) {
1489 case FIB_EVENT_NH_ADD:
1490 if (fib_nh->nh_flags & RTNH_F_DEAD)
1491 break;
1492 if (IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1493 fib_nh->nh_flags & RTNH_F_LINKDOWN)
1494 break;
1495 return call_fib4_notifiers(dev_net(fib_nh->nh_dev), event_type,
1496 &info.info);
1497 case FIB_EVENT_NH_DEL:
1498 if ((in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1499 fib_nh->nh_flags & RTNH_F_LINKDOWN) ||
1500 (fib_nh->nh_flags & RTNH_F_DEAD))
1501 return call_fib4_notifiers(dev_net(fib_nh->nh_dev),
1502 event_type, &info.info);
1503 default:
1504 break;
1505 }
1506
1507 return NOTIFY_DONE;
1508}
1509
1510/* Event force Flags Description
1511 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1512 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1513 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1514 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1515 */
1516int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1517{
1518 int ret = 0;
1519 int scope = RT_SCOPE_NOWHERE;
1520 struct fib_info *prev_fi = NULL;
1521 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1522 struct hlist_head *head = &fib_info_devhash[hash];
1523 struct fib_nh *nh;
1524
1525 if (force)
1526 scope = -1;
1527
1528 hlist_for_each_entry(nh, head, nh_hash) {
1529 struct fib_info *fi = nh->nh_parent;
1530 int dead;
1531
1532 BUG_ON(!fi->fib_nhs);
1533 if (nh->nh_dev != dev || fi == prev_fi)
1534 continue;
1535 prev_fi = fi;
1536 dead = 0;
1537 change_nexthops(fi) {
1538 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1539 dead++;
1540 else if (nexthop_nh->nh_dev == dev &&
1541 nexthop_nh->nh_scope != scope) {
1542 switch (event) {
1543 case NETDEV_DOWN:
1544 case NETDEV_UNREGISTER:
1545 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1546 /* fall through */
1547 case NETDEV_CHANGE:
1548 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1549 break;
1550 }
1551 call_fib_nh_notifiers(nexthop_nh,
1552 FIB_EVENT_NH_DEL);
1553 dead++;
1554 }
1555#ifdef CONFIG_IP_ROUTE_MULTIPATH
1556 if (event == NETDEV_UNREGISTER &&
1557 nexthop_nh->nh_dev == dev) {
1558 dead = fi->fib_nhs;
1559 break;
1560 }
1561#endif
1562 } endfor_nexthops(fi)
1563 if (dead == fi->fib_nhs) {
1564 switch (event) {
1565 case NETDEV_DOWN:
1566 case NETDEV_UNREGISTER:
1567 fi->fib_flags |= RTNH_F_DEAD;
1568 /* fall through */
1569 case NETDEV_CHANGE:
1570 fi->fib_flags |= RTNH_F_LINKDOWN;
1571 break;
1572 }
1573 ret++;
1574 }
1575
1576 fib_rebalance(fi);
1577 }
1578
1579 return ret;
1580}
1581
1582/* Must be invoked inside of an RCU protected region. */
1583static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1584{
1585 struct fib_info *fi = NULL, *last_resort = NULL;
1586 struct hlist_head *fa_head = res->fa_head;
1587 struct fib_table *tb = res->table;
1588 u8 slen = 32 - res->prefixlen;
1589 int order = -1, last_idx = -1;
1590 struct fib_alias *fa, *fa1 = NULL;
1591 u32 last_prio = res->fi->fib_priority;
1592 u8 last_tos = 0;
1593
1594 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1595 struct fib_info *next_fi = fa->fa_info;
1596
1597 if (fa->fa_slen != slen)
1598 continue;
1599 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1600 continue;
1601 if (fa->tb_id != tb->tb_id)
1602 continue;
1603 if (next_fi->fib_priority > last_prio &&
1604 fa->fa_tos == last_tos) {
1605 if (last_tos)
1606 continue;
1607 break;
1608 }
1609 if (next_fi->fib_flags & RTNH_F_DEAD)
1610 continue;
1611 last_tos = fa->fa_tos;
1612 last_prio = next_fi->fib_priority;
1613
1614 if (next_fi->fib_scope != res->scope ||
1615 fa->fa_type != RTN_UNICAST)
1616 continue;
1617 if (!next_fi->fib_nh[0].nh_gw ||
1618 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1619 continue;
1620
1621 fib_alias_accessed(fa);
1622
1623 if (!fi) {
1624 if (next_fi != res->fi)
1625 break;
1626 fa1 = fa;
1627 } else if (!fib_detect_death(fi, order, &last_resort,
1628 &last_idx, fa1->fa_default)) {
1629 fib_result_assign(res, fi);
1630 fa1->fa_default = order;
1631 goto out;
1632 }
1633 fi = next_fi;
1634 order++;
1635 }
1636
1637 if (order <= 0 || !fi) {
1638 if (fa1)
1639 fa1->fa_default = -1;
1640 goto out;
1641 }
1642
1643 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1644 fa1->fa_default)) {
1645 fib_result_assign(res, fi);
1646 fa1->fa_default = order;
1647 goto out;
1648 }
1649
1650 if (last_idx >= 0)
1651 fib_result_assign(res, last_resort);
1652 fa1->fa_default = last_idx;
1653out:
1654 return;
1655}
1656
1657/*
1658 * Dead device goes up. We wake up dead nexthops.
1659 * It takes sense only on multipath routes.
1660 */
1661int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1662{
1663 struct fib_info *prev_fi;
1664 unsigned int hash;
1665 struct hlist_head *head;
1666 struct fib_nh *nh;
1667 int ret;
1668
1669 if (!(dev->flags & IFF_UP))
1670 return 0;
1671
1672 if (nh_flags & RTNH_F_DEAD) {
1673 unsigned int flags = dev_get_flags(dev);
1674
1675 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1676 nh_flags |= RTNH_F_LINKDOWN;
1677 }
1678
1679 prev_fi = NULL;
1680 hash = fib_devindex_hashfn(dev->ifindex);
1681 head = &fib_info_devhash[hash];
1682 ret = 0;
1683
1684 hlist_for_each_entry(nh, head, nh_hash) {
1685 struct fib_info *fi = nh->nh_parent;
1686 int alive;
1687
1688 BUG_ON(!fi->fib_nhs);
1689 if (nh->nh_dev != dev || fi == prev_fi)
1690 continue;
1691
1692 prev_fi = fi;
1693 alive = 0;
1694 change_nexthops(fi) {
1695 if (!(nexthop_nh->nh_flags & nh_flags)) {
1696 alive++;
1697 continue;
1698 }
1699 if (!nexthop_nh->nh_dev ||
1700 !(nexthop_nh->nh_dev->flags & IFF_UP))
1701 continue;
1702 if (nexthop_nh->nh_dev != dev ||
1703 !__in_dev_get_rtnl(dev))
1704 continue;
1705 alive++;
1706 nexthop_nh->nh_flags &= ~nh_flags;
1707 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
1708 } endfor_nexthops(fi)
1709
1710 if (alive > 0) {
1711 fi->fib_flags &= ~nh_flags;
1712 ret++;
1713 }
1714
1715 fib_rebalance(fi);
1716 }
1717
1718 return ret;
1719}
1720
1721#ifdef CONFIG_IP_ROUTE_MULTIPATH
1722static bool fib_good_nh(const struct fib_nh *nh)
1723{
1724 int state = NUD_REACHABLE;
1725
1726 if (nh->nh_scope == RT_SCOPE_LINK) {
1727 struct neighbour *n;
1728
1729 rcu_read_lock_bh();
1730
1731 n = __ipv4_neigh_lookup_noref(nh->nh_dev,
1732 (__force u32)nh->nh_gw);
1733 if (n)
1734 state = n->nud_state;
1735
1736 rcu_read_unlock_bh();
1737 }
1738
1739 return !!(state & NUD_VALID);
1740}
1741
1742void fib_select_multipath(struct fib_result *res, int hash)
1743{
1744 struct fib_info *fi = res->fi;
1745 struct net *net = fi->fib_net;
1746 bool first = false;
1747
1748 for_nexthops(fi) {
1749 if (net->ipv4.sysctl_fib_multipath_use_neigh) {
1750 if (!fib_good_nh(nh))
1751 continue;
1752 if (!first) {
1753 res->nh_sel = nhsel;
1754 first = true;
1755 }
1756 }
1757
1758 if (hash > atomic_read(&nh->nh_upper_bound))
1759 continue;
1760
1761 res->nh_sel = nhsel;
1762 return;
1763 } endfor_nexthops(fi);
1764}
1765#endif
1766
1767void fib_select_path(struct net *net, struct fib_result *res,
1768 struct flowi4 *fl4, const struct sk_buff *skb)
1769{
1770 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
1771 goto check_saddr;
1772
1773#ifdef CONFIG_IP_ROUTE_MULTIPATH
1774 if (res->fi->fib_nhs > 1) {
1775 int h = fib_multipath_hash(net, fl4, skb, NULL);
1776
1777 fib_select_multipath(res, h);
1778 }
1779 else
1780#endif
1781 if (!res->prefixlen &&
1782 res->table->tb_num_default > 1 &&
1783 res->type == RTN_UNICAST)
1784 fib_select_default(fl4, res);
1785
1786check_saddr:
1787 if (!fl4->saddr)
1788 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1789}
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 <asm/uaccess.h>
17#include <asm/system.h>
18#include <linux/bitops.h>
19#include <linux/types.h>
20#include <linux/kernel.h>
21#include <linux/jiffies.h>
22#include <linux/mm.h>
23#include <linux/string.h>
24#include <linux/socket.h>
25#include <linux/sockios.h>
26#include <linux/errno.h>
27#include <linux/in.h>
28#include <linux/inet.h>
29#include <linux/inetdevice.h>
30#include <linux/netdevice.h>
31#include <linux/if_arp.h>
32#include <linux/proc_fs.h>
33#include <linux/skbuff.h>
34#include <linux/init.h>
35#include <linux/slab.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
47#include "fib_lookup.h"
48
49static DEFINE_SPINLOCK(fib_info_lock);
50static struct hlist_head *fib_info_hash;
51static struct hlist_head *fib_info_laddrhash;
52static unsigned int fib_info_hash_size;
53static unsigned int fib_info_cnt;
54
55#define DEVINDEX_HASHBITS 8
56#define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59#ifdef CONFIG_IP_ROUTE_MULTIPATH
60
61static DEFINE_SPINLOCK(fib_multipath_lock);
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
93const 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
144/* Release a nexthop info record */
145static void free_fib_info_rcu(struct rcu_head *head)
146{
147 struct fib_info *fi = container_of(head, struct fib_info, rcu);
148
149 if (fi->fib_metrics != (u32 *) dst_default_metrics)
150 kfree(fi->fib_metrics);
151 kfree(fi);
152}
153
154void free_fib_info(struct fib_info *fi)
155{
156 if (fi->fib_dead == 0) {
157 pr_warning("Freeing alive fib_info %p\n", fi);
158 return;
159 }
160 change_nexthops(fi) {
161 if (nexthop_nh->nh_dev)
162 dev_put(nexthop_nh->nh_dev);
163 nexthop_nh->nh_dev = NULL;
164 } endfor_nexthops(fi);
165 fib_info_cnt--;
166 release_net(fi->fib_net);
167 call_rcu(&fi->rcu, free_fib_info_rcu);
168}
169
170void fib_release_info(struct fib_info *fi)
171{
172 spin_lock_bh(&fib_info_lock);
173 if (fi && --fi->fib_treeref == 0) {
174 hlist_del(&fi->fib_hash);
175 if (fi->fib_prefsrc)
176 hlist_del(&fi->fib_lhash);
177 change_nexthops(fi) {
178 if (!nexthop_nh->nh_dev)
179 continue;
180 hlist_del(&nexthop_nh->nh_hash);
181 } endfor_nexthops(fi)
182 fi->fib_dead = 1;
183 fib_info_put(fi);
184 }
185 spin_unlock_bh(&fib_info_lock);
186}
187
188static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
189{
190 const struct fib_nh *onh = ofi->fib_nh;
191
192 for_nexthops(fi) {
193 if (nh->nh_oif != onh->nh_oif ||
194 nh->nh_gw != onh->nh_gw ||
195 nh->nh_scope != onh->nh_scope ||
196#ifdef CONFIG_IP_ROUTE_MULTIPATH
197 nh->nh_weight != onh->nh_weight ||
198#endif
199#ifdef CONFIG_IP_ROUTE_CLASSID
200 nh->nh_tclassid != onh->nh_tclassid ||
201#endif
202 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
203 return -1;
204 onh++;
205 } endfor_nexthops(fi);
206 return 0;
207}
208
209static inline unsigned int fib_devindex_hashfn(unsigned int val)
210{
211 unsigned int mask = DEVINDEX_HASHSIZE - 1;
212
213 return (val ^
214 (val >> DEVINDEX_HASHBITS) ^
215 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
216}
217
218static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
219{
220 unsigned int mask = (fib_info_hash_size - 1);
221 unsigned int val = fi->fib_nhs;
222
223 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
224 val ^= (__force u32)fi->fib_prefsrc;
225 val ^= fi->fib_priority;
226 for_nexthops(fi) {
227 val ^= fib_devindex_hashfn(nh->nh_oif);
228 } endfor_nexthops(fi)
229
230 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
231}
232
233static struct fib_info *fib_find_info(const struct fib_info *nfi)
234{
235 struct hlist_head *head;
236 struct hlist_node *node;
237 struct fib_info *fi;
238 unsigned int hash;
239
240 hash = fib_info_hashfn(nfi);
241 head = &fib_info_hash[hash];
242
243 hlist_for_each_entry(fi, node, head, fib_hash) {
244 if (!net_eq(fi->fib_net, nfi->fib_net))
245 continue;
246 if (fi->fib_nhs != nfi->fib_nhs)
247 continue;
248 if (nfi->fib_protocol == fi->fib_protocol &&
249 nfi->fib_scope == fi->fib_scope &&
250 nfi->fib_prefsrc == fi->fib_prefsrc &&
251 nfi->fib_priority == fi->fib_priority &&
252 memcmp(nfi->fib_metrics, fi->fib_metrics,
253 sizeof(u32) * RTAX_MAX) == 0 &&
254 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
255 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
256 return fi;
257 }
258
259 return NULL;
260}
261
262/* Check, that the gateway is already configured.
263 * Used only by redirect accept routine.
264 */
265int ip_fib_check_default(__be32 gw, struct net_device *dev)
266{
267 struct hlist_head *head;
268 struct hlist_node *node;
269 struct fib_nh *nh;
270 unsigned int hash;
271
272 spin_lock(&fib_info_lock);
273
274 hash = fib_devindex_hashfn(dev->ifindex);
275 head = &fib_info_devhash[hash];
276 hlist_for_each_entry(nh, node, head, nh_hash) {
277 if (nh->nh_dev == dev &&
278 nh->nh_gw == gw &&
279 !(nh->nh_flags & RTNH_F_DEAD)) {
280 spin_unlock(&fib_info_lock);
281 return 0;
282 }
283 }
284
285 spin_unlock(&fib_info_lock);
286
287 return -1;
288}
289
290static inline size_t fib_nlmsg_size(struct fib_info *fi)
291{
292 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
293 + nla_total_size(4) /* RTA_TABLE */
294 + nla_total_size(4) /* RTA_DST */
295 + nla_total_size(4) /* RTA_PRIORITY */
296 + nla_total_size(4); /* RTA_PREFSRC */
297
298 /* space for nested metrics */
299 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
300
301 if (fi->fib_nhs) {
302 /* Also handles the special case fib_nhs == 1 */
303
304 /* each nexthop is packed in an attribute */
305 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
306
307 /* may contain flow and gateway attribute */
308 nhsize += 2 * nla_total_size(4);
309
310 /* all nexthops are packed in a nested attribute */
311 payload += nla_total_size(fi->fib_nhs * nhsize);
312 }
313
314 return payload;
315}
316
317void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
318 int dst_len, u32 tb_id, struct nl_info *info,
319 unsigned int nlm_flags)
320{
321 struct sk_buff *skb;
322 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
323 int err = -ENOBUFS;
324
325 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
326 if (skb == NULL)
327 goto errout;
328
329 err = fib_dump_info(skb, info->pid, seq, event, tb_id,
330 fa->fa_type, key, dst_len,
331 fa->fa_tos, fa->fa_info, nlm_flags);
332 if (err < 0) {
333 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
334 WARN_ON(err == -EMSGSIZE);
335 kfree_skb(skb);
336 goto errout;
337 }
338 rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
339 info->nlh, GFP_KERNEL);
340 return;
341errout:
342 if (err < 0)
343 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
344}
345
346/* Return the first fib alias matching TOS with
347 * priority less than or equal to PRIO.
348 */
349struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
350{
351 if (fah) {
352 struct fib_alias *fa;
353 list_for_each_entry(fa, fah, fa_list) {
354 if (fa->fa_tos > tos)
355 continue;
356 if (fa->fa_info->fib_priority >= prio ||
357 fa->fa_tos < tos)
358 return fa;
359 }
360 }
361 return NULL;
362}
363
364int fib_detect_death(struct fib_info *fi, int order,
365 struct fib_info **last_resort, int *last_idx, int dflt)
366{
367 struct neighbour *n;
368 int state = NUD_NONE;
369
370 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
371 if (n) {
372 state = n->nud_state;
373 neigh_release(n);
374 }
375 if (state == NUD_REACHABLE)
376 return 0;
377 if ((state & NUD_VALID) && order != dflt)
378 return 0;
379 if ((state & NUD_VALID) ||
380 (*last_idx < 0 && order > dflt)) {
381 *last_resort = fi;
382 *last_idx = order;
383 }
384 return 1;
385}
386
387#ifdef CONFIG_IP_ROUTE_MULTIPATH
388
389static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
390{
391 int nhs = 0;
392
393 while (rtnh_ok(rtnh, remaining)) {
394 nhs++;
395 rtnh = rtnh_next(rtnh, &remaining);
396 }
397
398 /* leftover implies invalid nexthop configuration, discard it */
399 return remaining > 0 ? 0 : nhs;
400}
401
402static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
403 int remaining, struct fib_config *cfg)
404{
405 change_nexthops(fi) {
406 int attrlen;
407
408 if (!rtnh_ok(rtnh, remaining))
409 return -EINVAL;
410
411 nexthop_nh->nh_flags =
412 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
413 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
414 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
415
416 attrlen = rtnh_attrlen(rtnh);
417 if (attrlen > 0) {
418 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
419
420 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
421 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
422#ifdef CONFIG_IP_ROUTE_CLASSID
423 nla = nla_find(attrs, attrlen, RTA_FLOW);
424 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
425#endif
426 }
427
428 rtnh = rtnh_next(rtnh, &remaining);
429 } endfor_nexthops(fi);
430
431 return 0;
432}
433
434#endif
435
436int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
437{
438#ifdef CONFIG_IP_ROUTE_MULTIPATH
439 struct rtnexthop *rtnh;
440 int remaining;
441#endif
442
443 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
444 return 1;
445
446 if (cfg->fc_oif || cfg->fc_gw) {
447 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
448 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
449 return 0;
450 return 1;
451 }
452
453#ifdef CONFIG_IP_ROUTE_MULTIPATH
454 if (cfg->fc_mp == NULL)
455 return 0;
456
457 rtnh = cfg->fc_mp;
458 remaining = cfg->fc_mp_len;
459
460 for_nexthops(fi) {
461 int attrlen;
462
463 if (!rtnh_ok(rtnh, remaining))
464 return -EINVAL;
465
466 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
467 return 1;
468
469 attrlen = rtnh_attrlen(rtnh);
470 if (attrlen < 0) {
471 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
472
473 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
474 if (nla && nla_get_be32(nla) != nh->nh_gw)
475 return 1;
476#ifdef CONFIG_IP_ROUTE_CLASSID
477 nla = nla_find(attrs, attrlen, RTA_FLOW);
478 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
479 return 1;
480#endif
481 }
482
483 rtnh = rtnh_next(rtnh, &remaining);
484 } endfor_nexthops(fi);
485#endif
486 return 0;
487}
488
489
490/*
491 * Picture
492 * -------
493 *
494 * Semantics of nexthop is very messy by historical reasons.
495 * We have to take into account, that:
496 * a) gateway can be actually local interface address,
497 * so that gatewayed route is direct.
498 * b) gateway must be on-link address, possibly
499 * described not by an ifaddr, but also by a direct route.
500 * c) If both gateway and interface are specified, they should not
501 * contradict.
502 * d) If we use tunnel routes, gateway could be not on-link.
503 *
504 * Attempt to reconcile all of these (alas, self-contradictory) conditions
505 * results in pretty ugly and hairy code with obscure logic.
506 *
507 * I chose to generalized it instead, so that the size
508 * of code does not increase practically, but it becomes
509 * much more general.
510 * Every prefix is assigned a "scope" value: "host" is local address,
511 * "link" is direct route,
512 * [ ... "site" ... "interior" ... ]
513 * and "universe" is true gateway route with global meaning.
514 *
515 * Every prefix refers to a set of "nexthop"s (gw, oif),
516 * where gw must have narrower scope. This recursion stops
517 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
518 * which means that gw is forced to be on link.
519 *
520 * Code is still hairy, but now it is apparently logically
521 * consistent and very flexible. F.e. as by-product it allows
522 * to co-exists in peace independent exterior and interior
523 * routing processes.
524 *
525 * Normally it looks as following.
526 *
527 * {universe prefix} -> (gw, oif) [scope link]
528 * |
529 * |-> {link prefix} -> (gw, oif) [scope local]
530 * |
531 * |-> {local prefix} (terminal node)
532 */
533static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
534 struct fib_nh *nh)
535{
536 int err;
537 struct net *net;
538 struct net_device *dev;
539
540 net = cfg->fc_nlinfo.nl_net;
541 if (nh->nh_gw) {
542 struct fib_result res;
543
544 if (nh->nh_flags & RTNH_F_ONLINK) {
545
546 if (cfg->fc_scope >= RT_SCOPE_LINK)
547 return -EINVAL;
548 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
549 return -EINVAL;
550 dev = __dev_get_by_index(net, nh->nh_oif);
551 if (!dev)
552 return -ENODEV;
553 if (!(dev->flags & IFF_UP))
554 return -ENETDOWN;
555 nh->nh_dev = dev;
556 dev_hold(dev);
557 nh->nh_scope = RT_SCOPE_LINK;
558 return 0;
559 }
560 rcu_read_lock();
561 {
562 struct flowi4 fl4 = {
563 .daddr = nh->nh_gw,
564 .flowi4_scope = cfg->fc_scope + 1,
565 .flowi4_oif = nh->nh_oif,
566 };
567
568 /* It is not necessary, but requires a bit of thinking */
569 if (fl4.flowi4_scope < RT_SCOPE_LINK)
570 fl4.flowi4_scope = RT_SCOPE_LINK;
571 err = fib_lookup(net, &fl4, &res);
572 if (err) {
573 rcu_read_unlock();
574 return err;
575 }
576 }
577 err = -EINVAL;
578 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
579 goto out;
580 nh->nh_scope = res.scope;
581 nh->nh_oif = FIB_RES_OIF(res);
582 nh->nh_dev = dev = FIB_RES_DEV(res);
583 if (!dev)
584 goto out;
585 dev_hold(dev);
586 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
587 } else {
588 struct in_device *in_dev;
589
590 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
591 return -EINVAL;
592
593 rcu_read_lock();
594 err = -ENODEV;
595 in_dev = inetdev_by_index(net, nh->nh_oif);
596 if (in_dev == NULL)
597 goto out;
598 err = -ENETDOWN;
599 if (!(in_dev->dev->flags & IFF_UP))
600 goto out;
601 nh->nh_dev = in_dev->dev;
602 dev_hold(nh->nh_dev);
603 nh->nh_scope = RT_SCOPE_HOST;
604 err = 0;
605 }
606out:
607 rcu_read_unlock();
608 return err;
609}
610
611static inline unsigned int fib_laddr_hashfn(__be32 val)
612{
613 unsigned int mask = (fib_info_hash_size - 1);
614
615 return ((__force u32)val ^
616 ((__force u32)val >> 7) ^
617 ((__force u32)val >> 14)) & mask;
618}
619
620static struct hlist_head *fib_info_hash_alloc(int bytes)
621{
622 if (bytes <= PAGE_SIZE)
623 return kzalloc(bytes, GFP_KERNEL);
624 else
625 return (struct hlist_head *)
626 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
627 get_order(bytes));
628}
629
630static void fib_info_hash_free(struct hlist_head *hash, int bytes)
631{
632 if (!hash)
633 return;
634
635 if (bytes <= PAGE_SIZE)
636 kfree(hash);
637 else
638 free_pages((unsigned long) hash, get_order(bytes));
639}
640
641static void fib_info_hash_move(struct hlist_head *new_info_hash,
642 struct hlist_head *new_laddrhash,
643 unsigned int new_size)
644{
645 struct hlist_head *old_info_hash, *old_laddrhash;
646 unsigned int old_size = fib_info_hash_size;
647 unsigned int i, bytes;
648
649 spin_lock_bh(&fib_info_lock);
650 old_info_hash = fib_info_hash;
651 old_laddrhash = fib_info_laddrhash;
652 fib_info_hash_size = new_size;
653
654 for (i = 0; i < old_size; i++) {
655 struct hlist_head *head = &fib_info_hash[i];
656 struct hlist_node *node, *n;
657 struct fib_info *fi;
658
659 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
660 struct hlist_head *dest;
661 unsigned int new_hash;
662
663 hlist_del(&fi->fib_hash);
664
665 new_hash = fib_info_hashfn(fi);
666 dest = &new_info_hash[new_hash];
667 hlist_add_head(&fi->fib_hash, dest);
668 }
669 }
670 fib_info_hash = new_info_hash;
671
672 for (i = 0; i < old_size; i++) {
673 struct hlist_head *lhead = &fib_info_laddrhash[i];
674 struct hlist_node *node, *n;
675 struct fib_info *fi;
676
677 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
678 struct hlist_head *ldest;
679 unsigned int new_hash;
680
681 hlist_del(&fi->fib_lhash);
682
683 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
684 ldest = &new_laddrhash[new_hash];
685 hlist_add_head(&fi->fib_lhash, ldest);
686 }
687 }
688 fib_info_laddrhash = new_laddrhash;
689
690 spin_unlock_bh(&fib_info_lock);
691
692 bytes = old_size * sizeof(struct hlist_head *);
693 fib_info_hash_free(old_info_hash, bytes);
694 fib_info_hash_free(old_laddrhash, bytes);
695}
696
697__be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
698{
699 nh->nh_saddr = inet_select_addr(nh->nh_dev,
700 nh->nh_gw,
701 nh->nh_parent->fib_scope);
702 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
703
704 return nh->nh_saddr;
705}
706
707struct fib_info *fib_create_info(struct fib_config *cfg)
708{
709 int err;
710 struct fib_info *fi = NULL;
711 struct fib_info *ofi;
712 int nhs = 1;
713 struct net *net = cfg->fc_nlinfo.nl_net;
714
715 if (cfg->fc_type > RTN_MAX)
716 goto err_inval;
717
718 /* Fast check to catch the most weird cases */
719 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
720 goto err_inval;
721
722#ifdef CONFIG_IP_ROUTE_MULTIPATH
723 if (cfg->fc_mp) {
724 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
725 if (nhs == 0)
726 goto err_inval;
727 }
728#endif
729
730 err = -ENOBUFS;
731 if (fib_info_cnt >= fib_info_hash_size) {
732 unsigned int new_size = fib_info_hash_size << 1;
733 struct hlist_head *new_info_hash;
734 struct hlist_head *new_laddrhash;
735 unsigned int bytes;
736
737 if (!new_size)
738 new_size = 1;
739 bytes = new_size * sizeof(struct hlist_head *);
740 new_info_hash = fib_info_hash_alloc(bytes);
741 new_laddrhash = fib_info_hash_alloc(bytes);
742 if (!new_info_hash || !new_laddrhash) {
743 fib_info_hash_free(new_info_hash, bytes);
744 fib_info_hash_free(new_laddrhash, bytes);
745 } else
746 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
747
748 if (!fib_info_hash_size)
749 goto failure;
750 }
751
752 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
753 if (fi == NULL)
754 goto failure;
755 if (cfg->fc_mx) {
756 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
757 if (!fi->fib_metrics)
758 goto failure;
759 } else
760 fi->fib_metrics = (u32 *) dst_default_metrics;
761 fib_info_cnt++;
762
763 fi->fib_net = hold_net(net);
764 fi->fib_protocol = cfg->fc_protocol;
765 fi->fib_scope = cfg->fc_scope;
766 fi->fib_flags = cfg->fc_flags;
767 fi->fib_priority = cfg->fc_priority;
768 fi->fib_prefsrc = cfg->fc_prefsrc;
769
770 fi->fib_nhs = nhs;
771 change_nexthops(fi) {
772 nexthop_nh->nh_parent = fi;
773 } endfor_nexthops(fi)
774
775 if (cfg->fc_mx) {
776 struct nlattr *nla;
777 int remaining;
778
779 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
780 int type = nla_type(nla);
781
782 if (type) {
783 if (type > RTAX_MAX)
784 goto err_inval;
785 fi->fib_metrics[type - 1] = nla_get_u32(nla);
786 }
787 }
788 }
789
790 if (cfg->fc_mp) {
791#ifdef CONFIG_IP_ROUTE_MULTIPATH
792 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
793 if (err != 0)
794 goto failure;
795 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
796 goto err_inval;
797 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
798 goto err_inval;
799#ifdef CONFIG_IP_ROUTE_CLASSID
800 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
801 goto err_inval;
802#endif
803#else
804 goto err_inval;
805#endif
806 } else {
807 struct fib_nh *nh = fi->fib_nh;
808
809 nh->nh_oif = cfg->fc_oif;
810 nh->nh_gw = cfg->fc_gw;
811 nh->nh_flags = cfg->fc_flags;
812#ifdef CONFIG_IP_ROUTE_CLASSID
813 nh->nh_tclassid = cfg->fc_flow;
814#endif
815#ifdef CONFIG_IP_ROUTE_MULTIPATH
816 nh->nh_weight = 1;
817#endif
818 }
819
820 if (fib_props[cfg->fc_type].error) {
821 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
822 goto err_inval;
823 goto link_it;
824 } else {
825 switch (cfg->fc_type) {
826 case RTN_UNICAST:
827 case RTN_LOCAL:
828 case RTN_BROADCAST:
829 case RTN_ANYCAST:
830 case RTN_MULTICAST:
831 break;
832 default:
833 goto err_inval;
834 }
835 }
836
837 if (cfg->fc_scope > RT_SCOPE_HOST)
838 goto err_inval;
839
840 if (cfg->fc_scope == RT_SCOPE_HOST) {
841 struct fib_nh *nh = fi->fib_nh;
842
843 /* Local address is added. */
844 if (nhs != 1 || nh->nh_gw)
845 goto err_inval;
846 nh->nh_scope = RT_SCOPE_NOWHERE;
847 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
848 err = -ENODEV;
849 if (nh->nh_dev == NULL)
850 goto failure;
851 } else {
852 change_nexthops(fi) {
853 err = fib_check_nh(cfg, fi, nexthop_nh);
854 if (err != 0)
855 goto failure;
856 } endfor_nexthops(fi)
857 }
858
859 if (fi->fib_prefsrc) {
860 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
861 fi->fib_prefsrc != cfg->fc_dst)
862 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
863 goto err_inval;
864 }
865
866 change_nexthops(fi) {
867 fib_info_update_nh_saddr(net, nexthop_nh);
868 } endfor_nexthops(fi)
869
870link_it:
871 ofi = fib_find_info(fi);
872 if (ofi) {
873 fi->fib_dead = 1;
874 free_fib_info(fi);
875 ofi->fib_treeref++;
876 return ofi;
877 }
878
879 fi->fib_treeref++;
880 atomic_inc(&fi->fib_clntref);
881 spin_lock_bh(&fib_info_lock);
882 hlist_add_head(&fi->fib_hash,
883 &fib_info_hash[fib_info_hashfn(fi)]);
884 if (fi->fib_prefsrc) {
885 struct hlist_head *head;
886
887 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
888 hlist_add_head(&fi->fib_lhash, head);
889 }
890 change_nexthops(fi) {
891 struct hlist_head *head;
892 unsigned int hash;
893
894 if (!nexthop_nh->nh_dev)
895 continue;
896 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
897 head = &fib_info_devhash[hash];
898 hlist_add_head(&nexthop_nh->nh_hash, head);
899 } endfor_nexthops(fi)
900 spin_unlock_bh(&fib_info_lock);
901 return fi;
902
903err_inval:
904 err = -EINVAL;
905
906failure:
907 if (fi) {
908 fi->fib_dead = 1;
909 free_fib_info(fi);
910 }
911
912 return ERR_PTR(err);
913}
914
915int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
916 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
917 struct fib_info *fi, unsigned int flags)
918{
919 struct nlmsghdr *nlh;
920 struct rtmsg *rtm;
921
922 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
923 if (nlh == NULL)
924 return -EMSGSIZE;
925
926 rtm = nlmsg_data(nlh);
927 rtm->rtm_family = AF_INET;
928 rtm->rtm_dst_len = dst_len;
929 rtm->rtm_src_len = 0;
930 rtm->rtm_tos = tos;
931 if (tb_id < 256)
932 rtm->rtm_table = tb_id;
933 else
934 rtm->rtm_table = RT_TABLE_COMPAT;
935 NLA_PUT_U32(skb, RTA_TABLE, tb_id);
936 rtm->rtm_type = type;
937 rtm->rtm_flags = fi->fib_flags;
938 rtm->rtm_scope = fi->fib_scope;
939 rtm->rtm_protocol = fi->fib_protocol;
940
941 if (rtm->rtm_dst_len)
942 NLA_PUT_BE32(skb, RTA_DST, dst);
943
944 if (fi->fib_priority)
945 NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
946
947 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
948 goto nla_put_failure;
949
950 if (fi->fib_prefsrc)
951 NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc);
952
953 if (fi->fib_nhs == 1) {
954 if (fi->fib_nh->nh_gw)
955 NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
956
957 if (fi->fib_nh->nh_oif)
958 NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
959#ifdef CONFIG_IP_ROUTE_CLASSID
960 if (fi->fib_nh[0].nh_tclassid)
961 NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
962#endif
963 }
964#ifdef CONFIG_IP_ROUTE_MULTIPATH
965 if (fi->fib_nhs > 1) {
966 struct rtnexthop *rtnh;
967 struct nlattr *mp;
968
969 mp = nla_nest_start(skb, RTA_MULTIPATH);
970 if (mp == NULL)
971 goto nla_put_failure;
972
973 for_nexthops(fi) {
974 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
975 if (rtnh == NULL)
976 goto nla_put_failure;
977
978 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
979 rtnh->rtnh_hops = nh->nh_weight - 1;
980 rtnh->rtnh_ifindex = nh->nh_oif;
981
982 if (nh->nh_gw)
983 NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw);
984#ifdef CONFIG_IP_ROUTE_CLASSID
985 if (nh->nh_tclassid)
986 NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
987#endif
988 /* length of rtnetlink header + attributes */
989 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
990 } endfor_nexthops(fi);
991
992 nla_nest_end(skb, mp);
993 }
994#endif
995 return nlmsg_end(skb, nlh);
996
997nla_put_failure:
998 nlmsg_cancel(skb, nlh);
999 return -EMSGSIZE;
1000}
1001
1002/*
1003 * Update FIB if:
1004 * - local address disappeared -> we must delete all the entries
1005 * referring to it.
1006 * - device went down -> we must shutdown all nexthops going via it.
1007 */
1008int fib_sync_down_addr(struct net *net, __be32 local)
1009{
1010 int ret = 0;
1011 unsigned int hash = fib_laddr_hashfn(local);
1012 struct hlist_head *head = &fib_info_laddrhash[hash];
1013 struct hlist_node *node;
1014 struct fib_info *fi;
1015
1016 if (fib_info_laddrhash == NULL || local == 0)
1017 return 0;
1018
1019 hlist_for_each_entry(fi, node, head, fib_lhash) {
1020 if (!net_eq(fi->fib_net, net))
1021 continue;
1022 if (fi->fib_prefsrc == local) {
1023 fi->fib_flags |= RTNH_F_DEAD;
1024 ret++;
1025 }
1026 }
1027 return ret;
1028}
1029
1030int fib_sync_down_dev(struct net_device *dev, int force)
1031{
1032 int ret = 0;
1033 int scope = RT_SCOPE_NOWHERE;
1034 struct fib_info *prev_fi = NULL;
1035 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1036 struct hlist_head *head = &fib_info_devhash[hash];
1037 struct hlist_node *node;
1038 struct fib_nh *nh;
1039
1040 if (force)
1041 scope = -1;
1042
1043 hlist_for_each_entry(nh, node, head, nh_hash) {
1044 struct fib_info *fi = nh->nh_parent;
1045 int dead;
1046
1047 BUG_ON(!fi->fib_nhs);
1048 if (nh->nh_dev != dev || fi == prev_fi)
1049 continue;
1050 prev_fi = fi;
1051 dead = 0;
1052 change_nexthops(fi) {
1053 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1054 dead++;
1055 else if (nexthop_nh->nh_dev == dev &&
1056 nexthop_nh->nh_scope != scope) {
1057 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1058#ifdef CONFIG_IP_ROUTE_MULTIPATH
1059 spin_lock_bh(&fib_multipath_lock);
1060 fi->fib_power -= nexthop_nh->nh_power;
1061 nexthop_nh->nh_power = 0;
1062 spin_unlock_bh(&fib_multipath_lock);
1063#endif
1064 dead++;
1065 }
1066#ifdef CONFIG_IP_ROUTE_MULTIPATH
1067 if (force > 1 && nexthop_nh->nh_dev == dev) {
1068 dead = fi->fib_nhs;
1069 break;
1070 }
1071#endif
1072 } endfor_nexthops(fi)
1073 if (dead == fi->fib_nhs) {
1074 fi->fib_flags |= RTNH_F_DEAD;
1075 ret++;
1076 }
1077 }
1078
1079 return ret;
1080}
1081
1082/* Must be invoked inside of an RCU protected region. */
1083void fib_select_default(struct fib_result *res)
1084{
1085 struct fib_info *fi = NULL, *last_resort = NULL;
1086 struct list_head *fa_head = res->fa_head;
1087 struct fib_table *tb = res->table;
1088 int order = -1, last_idx = -1;
1089 struct fib_alias *fa;
1090
1091 list_for_each_entry_rcu(fa, fa_head, fa_list) {
1092 struct fib_info *next_fi = fa->fa_info;
1093
1094 if (next_fi->fib_scope != res->scope ||
1095 fa->fa_type != RTN_UNICAST)
1096 continue;
1097
1098 if (next_fi->fib_priority > res->fi->fib_priority)
1099 break;
1100 if (!next_fi->fib_nh[0].nh_gw ||
1101 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1102 continue;
1103
1104 fib_alias_accessed(fa);
1105
1106 if (fi == NULL) {
1107 if (next_fi != res->fi)
1108 break;
1109 } else if (!fib_detect_death(fi, order, &last_resort,
1110 &last_idx, tb->tb_default)) {
1111 fib_result_assign(res, fi);
1112 tb->tb_default = order;
1113 goto out;
1114 }
1115 fi = next_fi;
1116 order++;
1117 }
1118
1119 if (order <= 0 || fi == NULL) {
1120 tb->tb_default = -1;
1121 goto out;
1122 }
1123
1124 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1125 tb->tb_default)) {
1126 fib_result_assign(res, fi);
1127 tb->tb_default = order;
1128 goto out;
1129 }
1130
1131 if (last_idx >= 0)
1132 fib_result_assign(res, last_resort);
1133 tb->tb_default = last_idx;
1134out:
1135 return;
1136}
1137
1138#ifdef CONFIG_IP_ROUTE_MULTIPATH
1139
1140/*
1141 * Dead device goes up. We wake up dead nexthops.
1142 * It takes sense only on multipath routes.
1143 */
1144int fib_sync_up(struct net_device *dev)
1145{
1146 struct fib_info *prev_fi;
1147 unsigned int hash;
1148 struct hlist_head *head;
1149 struct hlist_node *node;
1150 struct fib_nh *nh;
1151 int ret;
1152
1153 if (!(dev->flags & IFF_UP))
1154 return 0;
1155
1156 prev_fi = NULL;
1157 hash = fib_devindex_hashfn(dev->ifindex);
1158 head = &fib_info_devhash[hash];
1159 ret = 0;
1160
1161 hlist_for_each_entry(nh, node, head, nh_hash) {
1162 struct fib_info *fi = nh->nh_parent;
1163 int alive;
1164
1165 BUG_ON(!fi->fib_nhs);
1166 if (nh->nh_dev != dev || fi == prev_fi)
1167 continue;
1168
1169 prev_fi = fi;
1170 alive = 0;
1171 change_nexthops(fi) {
1172 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1173 alive++;
1174 continue;
1175 }
1176 if (nexthop_nh->nh_dev == NULL ||
1177 !(nexthop_nh->nh_dev->flags & IFF_UP))
1178 continue;
1179 if (nexthop_nh->nh_dev != dev ||
1180 !__in_dev_get_rtnl(dev))
1181 continue;
1182 alive++;
1183 spin_lock_bh(&fib_multipath_lock);
1184 nexthop_nh->nh_power = 0;
1185 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1186 spin_unlock_bh(&fib_multipath_lock);
1187 } endfor_nexthops(fi)
1188
1189 if (alive > 0) {
1190 fi->fib_flags &= ~RTNH_F_DEAD;
1191 ret++;
1192 }
1193 }
1194
1195 return ret;
1196}
1197
1198/*
1199 * The algorithm is suboptimal, but it provides really
1200 * fair weighted route distribution.
1201 */
1202void fib_select_multipath(struct fib_result *res)
1203{
1204 struct fib_info *fi = res->fi;
1205 int w;
1206
1207 spin_lock_bh(&fib_multipath_lock);
1208 if (fi->fib_power <= 0) {
1209 int power = 0;
1210 change_nexthops(fi) {
1211 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1212 power += nexthop_nh->nh_weight;
1213 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1214 }
1215 } endfor_nexthops(fi);
1216 fi->fib_power = power;
1217 if (power <= 0) {
1218 spin_unlock_bh(&fib_multipath_lock);
1219 /* Race condition: route has just become dead. */
1220 res->nh_sel = 0;
1221 return;
1222 }
1223 }
1224
1225
1226 /* w should be random number [0..fi->fib_power-1],
1227 * it is pretty bad approximation.
1228 */
1229
1230 w = jiffies % fi->fib_power;
1231
1232 change_nexthops(fi) {
1233 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1234 nexthop_nh->nh_power) {
1235 w -= nexthop_nh->nh_power;
1236 if (w <= 0) {
1237 nexthop_nh->nh_power--;
1238 fi->fib_power--;
1239 res->nh_sel = nhsel;
1240 spin_unlock_bh(&fib_multipath_lock);
1241 return;
1242 }
1243 }
1244 } endfor_nexthops(fi);
1245
1246 /* Race condition: route has just become dead. */
1247 res->nh_sel = 0;
1248 spin_unlock_bh(&fib_multipath_lock);
1249}
1250#endif