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Merge tag 'tty-4.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
[deliverable/linux.git] / net / ipv4 / fib_semantics.c
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 <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
36 #include <net/arp.h>
37 #include <net/ip.h>
38 #include <net/protocol.h>
39 #include <net/route.h>
40 #include <net/tcp.h>
41 #include <net/sock.h>
42 #include <net/ip_fib.h>
43 #include <net/netlink.h>
44 #include <net/nexthop.h>
45 #include <net/lwtunnel.h>
46
47 #include "fib_lookup.h"
48
49 static DEFINE_SPINLOCK(fib_info_lock);
50 static struct hlist_head *fib_info_hash;
51 static struct hlist_head *fib_info_laddrhash;
52 static unsigned int fib_info_hash_size;
53 static unsigned int fib_info_cnt;
54
55 #define DEVINDEX_HASHBITS 8
56 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59 #ifdef CONFIG_IP_ROUTE_MULTIPATH
60 u32 fib_multipath_secret __read_mostly;
61
62 #define for_nexthops(fi) { \
63 int nhsel; const struct fib_nh *nh; \
64 for (nhsel = 0, nh = (fi)->fib_nh; \
65 nhsel < (fi)->fib_nhs; \
66 nh++, nhsel++)
67
68 #define change_nexthops(fi) { \
69 int nhsel; struct fib_nh *nexthop_nh; \
70 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
71 nhsel < (fi)->fib_nhs; \
72 nexthop_nh++, nhsel++)
73
74 #else /* CONFIG_IP_ROUTE_MULTIPATH */
75
76 /* Hope, that gcc will optimize it to get rid of dummy loop */
77
78 #define for_nexthops(fi) { \
79 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
80 for (nhsel = 0; nhsel < 1; nhsel++)
81
82 #define change_nexthops(fi) { \
83 int nhsel; \
84 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
88
89 #define endfor_nexthops(fi) }
90
91
92 const struct fib_prop fib_props[RTN_MAX + 1] = {
93 [RTN_UNSPEC] = {
94 .error = 0,
95 .scope = RT_SCOPE_NOWHERE,
96 },
97 [RTN_UNICAST] = {
98 .error = 0,
99 .scope = RT_SCOPE_UNIVERSE,
100 },
101 [RTN_LOCAL] = {
102 .error = 0,
103 .scope = RT_SCOPE_HOST,
104 },
105 [RTN_BROADCAST] = {
106 .error = 0,
107 .scope = RT_SCOPE_LINK,
108 },
109 [RTN_ANYCAST] = {
110 .error = 0,
111 .scope = RT_SCOPE_LINK,
112 },
113 [RTN_MULTICAST] = {
114 .error = 0,
115 .scope = RT_SCOPE_UNIVERSE,
116 },
117 [RTN_BLACKHOLE] = {
118 .error = -EINVAL,
119 .scope = RT_SCOPE_UNIVERSE,
120 },
121 [RTN_UNREACHABLE] = {
122 .error = -EHOSTUNREACH,
123 .scope = RT_SCOPE_UNIVERSE,
124 },
125 [RTN_PROHIBIT] = {
126 .error = -EACCES,
127 .scope = RT_SCOPE_UNIVERSE,
128 },
129 [RTN_THROW] = {
130 .error = -EAGAIN,
131 .scope = RT_SCOPE_UNIVERSE,
132 },
133 [RTN_NAT] = {
134 .error = -EINVAL,
135 .scope = RT_SCOPE_NOWHERE,
136 },
137 [RTN_XRESOLVE] = {
138 .error = -EINVAL,
139 .scope = RT_SCOPE_NOWHERE,
140 },
141 };
142
143 static void rt_fibinfo_free(struct rtable __rcu **rtp)
144 {
145 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
146
147 if (!rt)
148 return;
149
150 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
151 * because we waited an RCU grace period before calling
152 * free_fib_info_rcu()
153 */
154
155 dst_free(&rt->dst);
156 }
157
158 static void free_nh_exceptions(struct fib_nh *nh)
159 {
160 struct fnhe_hash_bucket *hash;
161 int i;
162
163 hash = rcu_dereference_protected(nh->nh_exceptions, 1);
164 if (!hash)
165 return;
166 for (i = 0; i < FNHE_HASH_SIZE; i++) {
167 struct fib_nh_exception *fnhe;
168
169 fnhe = rcu_dereference_protected(hash[i].chain, 1);
170 while (fnhe) {
171 struct fib_nh_exception *next;
172
173 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
174
175 rt_fibinfo_free(&fnhe->fnhe_rth_input);
176 rt_fibinfo_free(&fnhe->fnhe_rth_output);
177
178 kfree(fnhe);
179
180 fnhe = next;
181 }
182 }
183 kfree(hash);
184 }
185
186 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
187 {
188 int cpu;
189
190 if (!rtp)
191 return;
192
193 for_each_possible_cpu(cpu) {
194 struct rtable *rt;
195
196 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
197 if (rt)
198 dst_free(&rt->dst);
199 }
200 free_percpu(rtp);
201 }
202
203 /* Release a nexthop info record */
204 static void free_fib_info_rcu(struct rcu_head *head)
205 {
206 struct fib_info *fi = container_of(head, struct fib_info, rcu);
207
208 change_nexthops(fi) {
209 if (nexthop_nh->nh_dev)
210 dev_put(nexthop_nh->nh_dev);
211 lwtstate_put(nexthop_nh->nh_lwtstate);
212 free_nh_exceptions(nexthop_nh);
213 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
214 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
215 } endfor_nexthops(fi);
216
217 if (fi->fib_metrics != (u32 *) dst_default_metrics)
218 kfree(fi->fib_metrics);
219 kfree(fi);
220 }
221
222 void free_fib_info(struct fib_info *fi)
223 {
224 if (fi->fib_dead == 0) {
225 pr_warn("Freeing alive fib_info %p\n", fi);
226 return;
227 }
228 fib_info_cnt--;
229 #ifdef CONFIG_IP_ROUTE_CLASSID
230 change_nexthops(fi) {
231 if (nexthop_nh->nh_tclassid)
232 fi->fib_net->ipv4.fib_num_tclassid_users--;
233 } endfor_nexthops(fi);
234 #endif
235 call_rcu(&fi->rcu, free_fib_info_rcu);
236 }
237
238 void fib_release_info(struct fib_info *fi)
239 {
240 spin_lock_bh(&fib_info_lock);
241 if (fi && --fi->fib_treeref == 0) {
242 hlist_del(&fi->fib_hash);
243 if (fi->fib_prefsrc)
244 hlist_del(&fi->fib_lhash);
245 change_nexthops(fi) {
246 if (!nexthop_nh->nh_dev)
247 continue;
248 hlist_del(&nexthop_nh->nh_hash);
249 } endfor_nexthops(fi)
250 fi->fib_dead = 1;
251 fib_info_put(fi);
252 }
253 spin_unlock_bh(&fib_info_lock);
254 }
255
256 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
257 {
258 const struct fib_nh *onh = ofi->fib_nh;
259
260 for_nexthops(fi) {
261 if (nh->nh_oif != onh->nh_oif ||
262 nh->nh_gw != onh->nh_gw ||
263 nh->nh_scope != onh->nh_scope ||
264 #ifdef CONFIG_IP_ROUTE_MULTIPATH
265 nh->nh_weight != onh->nh_weight ||
266 #endif
267 #ifdef CONFIG_IP_ROUTE_CLASSID
268 nh->nh_tclassid != onh->nh_tclassid ||
269 #endif
270 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
271 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
272 return -1;
273 onh++;
274 } endfor_nexthops(fi);
275 return 0;
276 }
277
278 static inline unsigned int fib_devindex_hashfn(unsigned int val)
279 {
280 unsigned int mask = DEVINDEX_HASHSIZE - 1;
281
282 return (val ^
283 (val >> DEVINDEX_HASHBITS) ^
284 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
285 }
286
287 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
288 {
289 unsigned int mask = (fib_info_hash_size - 1);
290 unsigned int val = fi->fib_nhs;
291
292 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
293 val ^= (__force u32)fi->fib_prefsrc;
294 val ^= fi->fib_priority;
295 for_nexthops(fi) {
296 val ^= fib_devindex_hashfn(nh->nh_oif);
297 } endfor_nexthops(fi)
298
299 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
300 }
301
302 static struct fib_info *fib_find_info(const struct fib_info *nfi)
303 {
304 struct hlist_head *head;
305 struct fib_info *fi;
306 unsigned int hash;
307
308 hash = fib_info_hashfn(nfi);
309 head = &fib_info_hash[hash];
310
311 hlist_for_each_entry(fi, head, fib_hash) {
312 if (!net_eq(fi->fib_net, nfi->fib_net))
313 continue;
314 if (fi->fib_nhs != nfi->fib_nhs)
315 continue;
316 if (nfi->fib_protocol == fi->fib_protocol &&
317 nfi->fib_scope == fi->fib_scope &&
318 nfi->fib_prefsrc == fi->fib_prefsrc &&
319 nfi->fib_priority == fi->fib_priority &&
320 nfi->fib_type == fi->fib_type &&
321 memcmp(nfi->fib_metrics, fi->fib_metrics,
322 sizeof(u32) * RTAX_MAX) == 0 &&
323 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
324 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
325 return fi;
326 }
327
328 return NULL;
329 }
330
331 /* Check, that the gateway is already configured.
332 * Used only by redirect accept routine.
333 */
334 int ip_fib_check_default(__be32 gw, struct net_device *dev)
335 {
336 struct hlist_head *head;
337 struct fib_nh *nh;
338 unsigned int hash;
339
340 spin_lock(&fib_info_lock);
341
342 hash = fib_devindex_hashfn(dev->ifindex);
343 head = &fib_info_devhash[hash];
344 hlist_for_each_entry(nh, head, nh_hash) {
345 if (nh->nh_dev == dev &&
346 nh->nh_gw == gw &&
347 !(nh->nh_flags & RTNH_F_DEAD)) {
348 spin_unlock(&fib_info_lock);
349 return 0;
350 }
351 }
352
353 spin_unlock(&fib_info_lock);
354
355 return -1;
356 }
357
358 static inline size_t fib_nlmsg_size(struct fib_info *fi)
359 {
360 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
361 + nla_total_size(4) /* RTA_TABLE */
362 + nla_total_size(4) /* RTA_DST */
363 + nla_total_size(4) /* RTA_PRIORITY */
364 + nla_total_size(4) /* RTA_PREFSRC */
365 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
366
367 /* space for nested metrics */
368 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
369
370 if (fi->fib_nhs) {
371 size_t nh_encapsize = 0;
372 /* Also handles the special case fib_nhs == 1 */
373
374 /* each nexthop is packed in an attribute */
375 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
376
377 /* may contain flow and gateway attribute */
378 nhsize += 2 * nla_total_size(4);
379
380 /* grab encap info */
381 for_nexthops(fi) {
382 if (nh->nh_lwtstate) {
383 /* RTA_ENCAP_TYPE */
384 nh_encapsize += lwtunnel_get_encap_size(
385 nh->nh_lwtstate);
386 /* RTA_ENCAP */
387 nh_encapsize += nla_total_size(2);
388 }
389 } endfor_nexthops(fi);
390
391 /* all nexthops are packed in a nested attribute */
392 payload += nla_total_size((fi->fib_nhs * nhsize) +
393 nh_encapsize);
394
395 }
396
397 return payload;
398 }
399
400 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
401 int dst_len, u32 tb_id, const struct nl_info *info,
402 unsigned int nlm_flags)
403 {
404 struct sk_buff *skb;
405 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
406 int err = -ENOBUFS;
407
408 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
409 if (!skb)
410 goto errout;
411
412 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
413 fa->fa_type, key, dst_len,
414 fa->fa_tos, fa->fa_info, nlm_flags);
415 if (err < 0) {
416 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
417 WARN_ON(err == -EMSGSIZE);
418 kfree_skb(skb);
419 goto errout;
420 }
421 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
422 info->nlh, GFP_KERNEL);
423 return;
424 errout:
425 if (err < 0)
426 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
427 }
428
429 static int fib_detect_death(struct fib_info *fi, int order,
430 struct fib_info **last_resort, int *last_idx,
431 int dflt)
432 {
433 struct neighbour *n;
434 int state = NUD_NONE;
435
436 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
437 if (n) {
438 state = n->nud_state;
439 neigh_release(n);
440 } else {
441 return 0;
442 }
443 if (state == NUD_REACHABLE)
444 return 0;
445 if ((state & NUD_VALID) && order != dflt)
446 return 0;
447 if ((state & NUD_VALID) ||
448 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
449 *last_resort = fi;
450 *last_idx = order;
451 }
452 return 1;
453 }
454
455 #ifdef CONFIG_IP_ROUTE_MULTIPATH
456
457 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
458 {
459 int nhs = 0;
460
461 while (rtnh_ok(rtnh, remaining)) {
462 nhs++;
463 rtnh = rtnh_next(rtnh, &remaining);
464 }
465
466 /* leftover implies invalid nexthop configuration, discard it */
467 return remaining > 0 ? 0 : nhs;
468 }
469
470 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
471 int remaining, struct fib_config *cfg)
472 {
473 struct net *net = cfg->fc_nlinfo.nl_net;
474 int ret;
475
476 change_nexthops(fi) {
477 int attrlen;
478
479 if (!rtnh_ok(rtnh, remaining))
480 return -EINVAL;
481
482 nexthop_nh->nh_flags =
483 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
484 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
485 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
486
487 attrlen = rtnh_attrlen(rtnh);
488 if (attrlen > 0) {
489 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
490
491 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
492 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
493 #ifdef CONFIG_IP_ROUTE_CLASSID
494 nla = nla_find(attrs, attrlen, RTA_FLOW);
495 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
496 if (nexthop_nh->nh_tclassid)
497 fi->fib_net->ipv4.fib_num_tclassid_users++;
498 #endif
499 nla = nla_find(attrs, attrlen, RTA_ENCAP);
500 if (nla) {
501 struct lwtunnel_state *lwtstate;
502 struct net_device *dev = NULL;
503 struct nlattr *nla_entype;
504
505 nla_entype = nla_find(attrs, attrlen,
506 RTA_ENCAP_TYPE);
507 if (!nla_entype)
508 goto err_inval;
509 if (cfg->fc_oif)
510 dev = __dev_get_by_index(net, cfg->fc_oif);
511 ret = lwtunnel_build_state(dev, nla_get_u16(
512 nla_entype),
513 nla, AF_INET, cfg,
514 &lwtstate);
515 if (ret)
516 goto errout;
517 nexthop_nh->nh_lwtstate =
518 lwtstate_get(lwtstate);
519 }
520 }
521
522 rtnh = rtnh_next(rtnh, &remaining);
523 } endfor_nexthops(fi);
524
525 return 0;
526
527 err_inval:
528 ret = -EINVAL;
529
530 errout:
531 return ret;
532 }
533
534 static void fib_rebalance(struct fib_info *fi)
535 {
536 int total;
537 int w;
538 struct in_device *in_dev;
539
540 if (fi->fib_nhs < 2)
541 return;
542
543 total = 0;
544 for_nexthops(fi) {
545 if (nh->nh_flags & RTNH_F_DEAD)
546 continue;
547
548 in_dev = __in_dev_get_rtnl(nh->nh_dev);
549
550 if (in_dev &&
551 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
552 nh->nh_flags & RTNH_F_LINKDOWN)
553 continue;
554
555 total += nh->nh_weight;
556 } endfor_nexthops(fi);
557
558 w = 0;
559 change_nexthops(fi) {
560 int upper_bound;
561
562 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
563
564 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
565 upper_bound = -1;
566 } else if (in_dev &&
567 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
568 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
569 upper_bound = -1;
570 } else {
571 w += nexthop_nh->nh_weight;
572 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
573 total) - 1;
574 }
575
576 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
577 } endfor_nexthops(fi);
578
579 net_get_random_once(&fib_multipath_secret,
580 sizeof(fib_multipath_secret));
581 }
582
583 static inline void fib_add_weight(struct fib_info *fi,
584 const struct fib_nh *nh)
585 {
586 fi->fib_weight += nh->nh_weight;
587 }
588
589 #else /* CONFIG_IP_ROUTE_MULTIPATH */
590
591 #define fib_rebalance(fi) do { } while (0)
592 #define fib_add_weight(fi, nh) do { } while (0)
593
594 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
595
596 static int fib_encap_match(struct net *net, u16 encap_type,
597 struct nlattr *encap,
598 int oif, const struct fib_nh *nh,
599 const struct fib_config *cfg)
600 {
601 struct lwtunnel_state *lwtstate;
602 struct net_device *dev = NULL;
603 int ret, result = 0;
604
605 if (encap_type == LWTUNNEL_ENCAP_NONE)
606 return 0;
607
608 if (oif)
609 dev = __dev_get_by_index(net, oif);
610 ret = lwtunnel_build_state(dev, encap_type, encap,
611 AF_INET, cfg, &lwtstate);
612 if (!ret) {
613 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
614 lwtstate_free(lwtstate);
615 }
616
617 return result;
618 }
619
620 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
621 {
622 struct net *net = cfg->fc_nlinfo.nl_net;
623 #ifdef CONFIG_IP_ROUTE_MULTIPATH
624 struct rtnexthop *rtnh;
625 int remaining;
626 #endif
627
628 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
629 return 1;
630
631 if (cfg->fc_oif || cfg->fc_gw) {
632 if (cfg->fc_encap) {
633 if (fib_encap_match(net, cfg->fc_encap_type,
634 cfg->fc_encap, cfg->fc_oif,
635 fi->fib_nh, cfg))
636 return 1;
637 }
638 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
639 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
640 return 0;
641 return 1;
642 }
643
644 #ifdef CONFIG_IP_ROUTE_MULTIPATH
645 if (!cfg->fc_mp)
646 return 0;
647
648 rtnh = cfg->fc_mp;
649 remaining = cfg->fc_mp_len;
650
651 for_nexthops(fi) {
652 int attrlen;
653
654 if (!rtnh_ok(rtnh, remaining))
655 return -EINVAL;
656
657 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
658 return 1;
659
660 attrlen = rtnh_attrlen(rtnh);
661 if (attrlen > 0) {
662 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
663
664 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
665 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
666 return 1;
667 #ifdef CONFIG_IP_ROUTE_CLASSID
668 nla = nla_find(attrs, attrlen, RTA_FLOW);
669 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
670 return 1;
671 #endif
672 }
673
674 rtnh = rtnh_next(rtnh, &remaining);
675 } endfor_nexthops(fi);
676 #endif
677 return 0;
678 }
679
680
681 /*
682 * Picture
683 * -------
684 *
685 * Semantics of nexthop is very messy by historical reasons.
686 * We have to take into account, that:
687 * a) gateway can be actually local interface address,
688 * so that gatewayed route is direct.
689 * b) gateway must be on-link address, possibly
690 * described not by an ifaddr, but also by a direct route.
691 * c) If both gateway and interface are specified, they should not
692 * contradict.
693 * d) If we use tunnel routes, gateway could be not on-link.
694 *
695 * Attempt to reconcile all of these (alas, self-contradictory) conditions
696 * results in pretty ugly and hairy code with obscure logic.
697 *
698 * I chose to generalized it instead, so that the size
699 * of code does not increase practically, but it becomes
700 * much more general.
701 * Every prefix is assigned a "scope" value: "host" is local address,
702 * "link" is direct route,
703 * [ ... "site" ... "interior" ... ]
704 * and "universe" is true gateway route with global meaning.
705 *
706 * Every prefix refers to a set of "nexthop"s (gw, oif),
707 * where gw must have narrower scope. This recursion stops
708 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
709 * which means that gw is forced to be on link.
710 *
711 * Code is still hairy, but now it is apparently logically
712 * consistent and very flexible. F.e. as by-product it allows
713 * to co-exists in peace independent exterior and interior
714 * routing processes.
715 *
716 * Normally it looks as following.
717 *
718 * {universe prefix} -> (gw, oif) [scope link]
719 * |
720 * |-> {link prefix} -> (gw, oif) [scope local]
721 * |
722 * |-> {local prefix} (terminal node)
723 */
724 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
725 struct fib_nh *nh)
726 {
727 int err = 0;
728 struct net *net;
729 struct net_device *dev;
730
731 net = cfg->fc_nlinfo.nl_net;
732 if (nh->nh_gw) {
733 struct fib_result res;
734
735 if (nh->nh_flags & RTNH_F_ONLINK) {
736 unsigned int addr_type;
737
738 if (cfg->fc_scope >= RT_SCOPE_LINK)
739 return -EINVAL;
740 dev = __dev_get_by_index(net, nh->nh_oif);
741 if (!dev)
742 return -ENODEV;
743 if (!(dev->flags & IFF_UP))
744 return -ENETDOWN;
745 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
746 if (addr_type != RTN_UNICAST)
747 return -EINVAL;
748 if (!netif_carrier_ok(dev))
749 nh->nh_flags |= RTNH_F_LINKDOWN;
750 nh->nh_dev = dev;
751 dev_hold(dev);
752 nh->nh_scope = RT_SCOPE_LINK;
753 return 0;
754 }
755 rcu_read_lock();
756 {
757 struct fib_table *tbl = NULL;
758 struct flowi4 fl4 = {
759 .daddr = nh->nh_gw,
760 .flowi4_scope = cfg->fc_scope + 1,
761 .flowi4_oif = nh->nh_oif,
762 .flowi4_iif = LOOPBACK_IFINDEX,
763 };
764
765 /* It is not necessary, but requires a bit of thinking */
766 if (fl4.flowi4_scope < RT_SCOPE_LINK)
767 fl4.flowi4_scope = RT_SCOPE_LINK;
768
769 if (cfg->fc_table)
770 tbl = fib_get_table(net, cfg->fc_table);
771
772 if (tbl)
773 err = fib_table_lookup(tbl, &fl4, &res,
774 FIB_LOOKUP_IGNORE_LINKSTATE |
775 FIB_LOOKUP_NOREF);
776
777 /* on error or if no table given do full lookup. This
778 * is needed for example when nexthops are in the local
779 * table rather than the given table
780 */
781 if (!tbl || err) {
782 err = fib_lookup(net, &fl4, &res,
783 FIB_LOOKUP_IGNORE_LINKSTATE);
784 }
785
786 if (err) {
787 rcu_read_unlock();
788 return err;
789 }
790 }
791 err = -EINVAL;
792 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
793 goto out;
794 nh->nh_scope = res.scope;
795 nh->nh_oif = FIB_RES_OIF(res);
796 nh->nh_dev = dev = FIB_RES_DEV(res);
797 if (!dev)
798 goto out;
799 dev_hold(dev);
800 if (!netif_carrier_ok(dev))
801 nh->nh_flags |= RTNH_F_LINKDOWN;
802 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
803 } else {
804 struct in_device *in_dev;
805
806 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
807 return -EINVAL;
808
809 rcu_read_lock();
810 err = -ENODEV;
811 in_dev = inetdev_by_index(net, nh->nh_oif);
812 if (!in_dev)
813 goto out;
814 err = -ENETDOWN;
815 if (!(in_dev->dev->flags & IFF_UP))
816 goto out;
817 nh->nh_dev = in_dev->dev;
818 dev_hold(nh->nh_dev);
819 nh->nh_scope = RT_SCOPE_HOST;
820 if (!netif_carrier_ok(nh->nh_dev))
821 nh->nh_flags |= RTNH_F_LINKDOWN;
822 err = 0;
823 }
824 out:
825 rcu_read_unlock();
826 return err;
827 }
828
829 static inline unsigned int fib_laddr_hashfn(__be32 val)
830 {
831 unsigned int mask = (fib_info_hash_size - 1);
832
833 return ((__force u32)val ^
834 ((__force u32)val >> 7) ^
835 ((__force u32)val >> 14)) & mask;
836 }
837
838 static struct hlist_head *fib_info_hash_alloc(int bytes)
839 {
840 if (bytes <= PAGE_SIZE)
841 return kzalloc(bytes, GFP_KERNEL);
842 else
843 return (struct hlist_head *)
844 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
845 get_order(bytes));
846 }
847
848 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
849 {
850 if (!hash)
851 return;
852
853 if (bytes <= PAGE_SIZE)
854 kfree(hash);
855 else
856 free_pages((unsigned long) hash, get_order(bytes));
857 }
858
859 static void fib_info_hash_move(struct hlist_head *new_info_hash,
860 struct hlist_head *new_laddrhash,
861 unsigned int new_size)
862 {
863 struct hlist_head *old_info_hash, *old_laddrhash;
864 unsigned int old_size = fib_info_hash_size;
865 unsigned int i, bytes;
866
867 spin_lock_bh(&fib_info_lock);
868 old_info_hash = fib_info_hash;
869 old_laddrhash = fib_info_laddrhash;
870 fib_info_hash_size = new_size;
871
872 for (i = 0; i < old_size; i++) {
873 struct hlist_head *head = &fib_info_hash[i];
874 struct hlist_node *n;
875 struct fib_info *fi;
876
877 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
878 struct hlist_head *dest;
879 unsigned int new_hash;
880
881 new_hash = fib_info_hashfn(fi);
882 dest = &new_info_hash[new_hash];
883 hlist_add_head(&fi->fib_hash, dest);
884 }
885 }
886 fib_info_hash = new_info_hash;
887
888 for (i = 0; i < old_size; i++) {
889 struct hlist_head *lhead = &fib_info_laddrhash[i];
890 struct hlist_node *n;
891 struct fib_info *fi;
892
893 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
894 struct hlist_head *ldest;
895 unsigned int new_hash;
896
897 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
898 ldest = &new_laddrhash[new_hash];
899 hlist_add_head(&fi->fib_lhash, ldest);
900 }
901 }
902 fib_info_laddrhash = new_laddrhash;
903
904 spin_unlock_bh(&fib_info_lock);
905
906 bytes = old_size * sizeof(struct hlist_head *);
907 fib_info_hash_free(old_info_hash, bytes);
908 fib_info_hash_free(old_laddrhash, bytes);
909 }
910
911 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
912 {
913 nh->nh_saddr = inet_select_addr(nh->nh_dev,
914 nh->nh_gw,
915 nh->nh_parent->fib_scope);
916 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
917
918 return nh->nh_saddr;
919 }
920
921 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
922 {
923 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
924 fib_prefsrc != cfg->fc_dst) {
925 u32 tb_id = cfg->fc_table;
926 int rc;
927
928 if (tb_id == RT_TABLE_MAIN)
929 tb_id = RT_TABLE_LOCAL;
930
931 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
932 fib_prefsrc, tb_id);
933
934 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
935 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
936 fib_prefsrc, RT_TABLE_LOCAL);
937 }
938
939 if (rc != RTN_LOCAL)
940 return false;
941 }
942 return true;
943 }
944
945 static int
946 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
947 {
948 bool ecn_ca = false;
949 struct nlattr *nla;
950 int remaining;
951
952 if (!cfg->fc_mx)
953 return 0;
954
955 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
956 int type = nla_type(nla);
957 u32 val;
958
959 if (!type)
960 continue;
961 if (type > RTAX_MAX)
962 return -EINVAL;
963
964 if (type == RTAX_CC_ALGO) {
965 char tmp[TCP_CA_NAME_MAX];
966
967 nla_strlcpy(tmp, nla, sizeof(tmp));
968 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
969 if (val == TCP_CA_UNSPEC)
970 return -EINVAL;
971 } else {
972 val = nla_get_u32(nla);
973 }
974 if (type == RTAX_ADVMSS && val > 65535 - 40)
975 val = 65535 - 40;
976 if (type == RTAX_MTU && val > 65535 - 15)
977 val = 65535 - 15;
978 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
979 return -EINVAL;
980 fi->fib_metrics[type - 1] = val;
981 }
982
983 if (ecn_ca)
984 fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
985
986 return 0;
987 }
988
989 struct fib_info *fib_create_info(struct fib_config *cfg)
990 {
991 int err;
992 struct fib_info *fi = NULL;
993 struct fib_info *ofi;
994 int nhs = 1;
995 struct net *net = cfg->fc_nlinfo.nl_net;
996
997 if (cfg->fc_type > RTN_MAX)
998 goto err_inval;
999
1000 /* Fast check to catch the most weird cases */
1001 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
1002 goto err_inval;
1003
1004 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1005 if (cfg->fc_mp) {
1006 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
1007 if (nhs == 0)
1008 goto err_inval;
1009 }
1010 #endif
1011
1012 err = -ENOBUFS;
1013 if (fib_info_cnt >= fib_info_hash_size) {
1014 unsigned int new_size = fib_info_hash_size << 1;
1015 struct hlist_head *new_info_hash;
1016 struct hlist_head *new_laddrhash;
1017 unsigned int bytes;
1018
1019 if (!new_size)
1020 new_size = 16;
1021 bytes = new_size * sizeof(struct hlist_head *);
1022 new_info_hash = fib_info_hash_alloc(bytes);
1023 new_laddrhash = fib_info_hash_alloc(bytes);
1024 if (!new_info_hash || !new_laddrhash) {
1025 fib_info_hash_free(new_info_hash, bytes);
1026 fib_info_hash_free(new_laddrhash, bytes);
1027 } else
1028 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1029
1030 if (!fib_info_hash_size)
1031 goto failure;
1032 }
1033
1034 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1035 if (!fi)
1036 goto failure;
1037 fib_info_cnt++;
1038 if (cfg->fc_mx) {
1039 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
1040 if (!fi->fib_metrics)
1041 goto failure;
1042 } else
1043 fi->fib_metrics = (u32 *) dst_default_metrics;
1044
1045 fi->fib_net = net;
1046 fi->fib_protocol = cfg->fc_protocol;
1047 fi->fib_scope = cfg->fc_scope;
1048 fi->fib_flags = cfg->fc_flags;
1049 fi->fib_priority = cfg->fc_priority;
1050 fi->fib_prefsrc = cfg->fc_prefsrc;
1051 fi->fib_type = cfg->fc_type;
1052
1053 fi->fib_nhs = nhs;
1054 change_nexthops(fi) {
1055 nexthop_nh->nh_parent = fi;
1056 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1057 if (!nexthop_nh->nh_pcpu_rth_output)
1058 goto failure;
1059 } endfor_nexthops(fi)
1060
1061 err = fib_convert_metrics(fi, cfg);
1062 if (err)
1063 goto failure;
1064
1065 if (cfg->fc_mp) {
1066 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1067 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
1068 if (err != 0)
1069 goto failure;
1070 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
1071 goto err_inval;
1072 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
1073 goto err_inval;
1074 #ifdef CONFIG_IP_ROUTE_CLASSID
1075 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
1076 goto err_inval;
1077 #endif
1078 #else
1079 goto err_inval;
1080 #endif
1081 } else {
1082 struct fib_nh *nh = fi->fib_nh;
1083
1084 if (cfg->fc_encap) {
1085 struct lwtunnel_state *lwtstate;
1086 struct net_device *dev = NULL;
1087
1088 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE)
1089 goto err_inval;
1090 if (cfg->fc_oif)
1091 dev = __dev_get_by_index(net, cfg->fc_oif);
1092 err = lwtunnel_build_state(dev, cfg->fc_encap_type,
1093 cfg->fc_encap, AF_INET, cfg,
1094 &lwtstate);
1095 if (err)
1096 goto failure;
1097
1098 nh->nh_lwtstate = lwtstate_get(lwtstate);
1099 }
1100 nh->nh_oif = cfg->fc_oif;
1101 nh->nh_gw = cfg->fc_gw;
1102 nh->nh_flags = cfg->fc_flags;
1103 #ifdef CONFIG_IP_ROUTE_CLASSID
1104 nh->nh_tclassid = cfg->fc_flow;
1105 if (nh->nh_tclassid)
1106 fi->fib_net->ipv4.fib_num_tclassid_users++;
1107 #endif
1108 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1109 nh->nh_weight = 1;
1110 #endif
1111 }
1112
1113 if (fib_props[cfg->fc_type].error) {
1114 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
1115 goto err_inval;
1116 goto link_it;
1117 } else {
1118 switch (cfg->fc_type) {
1119 case RTN_UNICAST:
1120 case RTN_LOCAL:
1121 case RTN_BROADCAST:
1122 case RTN_ANYCAST:
1123 case RTN_MULTICAST:
1124 break;
1125 default:
1126 goto err_inval;
1127 }
1128 }
1129
1130 if (cfg->fc_scope > RT_SCOPE_HOST)
1131 goto err_inval;
1132
1133 if (cfg->fc_scope == RT_SCOPE_HOST) {
1134 struct fib_nh *nh = fi->fib_nh;
1135
1136 /* Local address is added. */
1137 if (nhs != 1 || nh->nh_gw)
1138 goto err_inval;
1139 nh->nh_scope = RT_SCOPE_NOWHERE;
1140 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1141 err = -ENODEV;
1142 if (!nh->nh_dev)
1143 goto failure;
1144 } else {
1145 int linkdown = 0;
1146
1147 change_nexthops(fi) {
1148 err = fib_check_nh(cfg, fi, nexthop_nh);
1149 if (err != 0)
1150 goto failure;
1151 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1152 linkdown++;
1153 } endfor_nexthops(fi)
1154 if (linkdown == fi->fib_nhs)
1155 fi->fib_flags |= RTNH_F_LINKDOWN;
1156 }
1157
1158 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc))
1159 goto err_inval;
1160
1161 change_nexthops(fi) {
1162 fib_info_update_nh_saddr(net, nexthop_nh);
1163 fib_add_weight(fi, nexthop_nh);
1164 } endfor_nexthops(fi)
1165
1166 fib_rebalance(fi);
1167
1168 link_it:
1169 ofi = fib_find_info(fi);
1170 if (ofi) {
1171 fi->fib_dead = 1;
1172 free_fib_info(fi);
1173 ofi->fib_treeref++;
1174 return ofi;
1175 }
1176
1177 fi->fib_treeref++;
1178 atomic_inc(&fi->fib_clntref);
1179 spin_lock_bh(&fib_info_lock);
1180 hlist_add_head(&fi->fib_hash,
1181 &fib_info_hash[fib_info_hashfn(fi)]);
1182 if (fi->fib_prefsrc) {
1183 struct hlist_head *head;
1184
1185 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1186 hlist_add_head(&fi->fib_lhash, head);
1187 }
1188 change_nexthops(fi) {
1189 struct hlist_head *head;
1190 unsigned int hash;
1191
1192 if (!nexthop_nh->nh_dev)
1193 continue;
1194 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1195 head = &fib_info_devhash[hash];
1196 hlist_add_head(&nexthop_nh->nh_hash, head);
1197 } endfor_nexthops(fi)
1198 spin_unlock_bh(&fib_info_lock);
1199 return fi;
1200
1201 err_inval:
1202 err = -EINVAL;
1203
1204 failure:
1205 if (fi) {
1206 fi->fib_dead = 1;
1207 free_fib_info(fi);
1208 }
1209
1210 return ERR_PTR(err);
1211 }
1212
1213 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1214 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1215 struct fib_info *fi, unsigned int flags)
1216 {
1217 struct nlmsghdr *nlh;
1218 struct rtmsg *rtm;
1219
1220 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1221 if (!nlh)
1222 return -EMSGSIZE;
1223
1224 rtm = nlmsg_data(nlh);
1225 rtm->rtm_family = AF_INET;
1226 rtm->rtm_dst_len = dst_len;
1227 rtm->rtm_src_len = 0;
1228 rtm->rtm_tos = tos;
1229 if (tb_id < 256)
1230 rtm->rtm_table = tb_id;
1231 else
1232 rtm->rtm_table = RT_TABLE_COMPAT;
1233 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1234 goto nla_put_failure;
1235 rtm->rtm_type = type;
1236 rtm->rtm_flags = fi->fib_flags;
1237 rtm->rtm_scope = fi->fib_scope;
1238 rtm->rtm_protocol = fi->fib_protocol;
1239
1240 if (rtm->rtm_dst_len &&
1241 nla_put_in_addr(skb, RTA_DST, dst))
1242 goto nla_put_failure;
1243 if (fi->fib_priority &&
1244 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1245 goto nla_put_failure;
1246 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
1247 goto nla_put_failure;
1248
1249 if (fi->fib_prefsrc &&
1250 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1251 goto nla_put_failure;
1252 if (fi->fib_nhs == 1) {
1253 struct in_device *in_dev;
1254
1255 if (fi->fib_nh->nh_gw &&
1256 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1257 goto nla_put_failure;
1258 if (fi->fib_nh->nh_oif &&
1259 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1260 goto nla_put_failure;
1261 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1262 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev);
1263 if (in_dev &&
1264 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1265 rtm->rtm_flags |= RTNH_F_DEAD;
1266 }
1267 #ifdef CONFIG_IP_ROUTE_CLASSID
1268 if (fi->fib_nh[0].nh_tclassid &&
1269 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1270 goto nla_put_failure;
1271 #endif
1272 if (fi->fib_nh->nh_lwtstate)
1273 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate);
1274 }
1275 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1276 if (fi->fib_nhs > 1) {
1277 struct rtnexthop *rtnh;
1278 struct nlattr *mp;
1279
1280 mp = nla_nest_start(skb, RTA_MULTIPATH);
1281 if (!mp)
1282 goto nla_put_failure;
1283
1284 for_nexthops(fi) {
1285 struct in_device *in_dev;
1286
1287 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1288 if (!rtnh)
1289 goto nla_put_failure;
1290
1291 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1292 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1293 in_dev = __in_dev_get_rtnl(nh->nh_dev);
1294 if (in_dev &&
1295 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1296 rtnh->rtnh_flags |= RTNH_F_DEAD;
1297 }
1298 rtnh->rtnh_hops = nh->nh_weight - 1;
1299 rtnh->rtnh_ifindex = nh->nh_oif;
1300
1301 if (nh->nh_gw &&
1302 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1303 goto nla_put_failure;
1304 #ifdef CONFIG_IP_ROUTE_CLASSID
1305 if (nh->nh_tclassid &&
1306 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1307 goto nla_put_failure;
1308 #endif
1309 if (nh->nh_lwtstate)
1310 lwtunnel_fill_encap(skb, nh->nh_lwtstate);
1311 /* length of rtnetlink header + attributes */
1312 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1313 } endfor_nexthops(fi);
1314
1315 nla_nest_end(skb, mp);
1316 }
1317 #endif
1318 nlmsg_end(skb, nlh);
1319 return 0;
1320
1321 nla_put_failure:
1322 nlmsg_cancel(skb, nlh);
1323 return -EMSGSIZE;
1324 }
1325
1326 /*
1327 * Update FIB if:
1328 * - local address disappeared -> we must delete all the entries
1329 * referring to it.
1330 * - device went down -> we must shutdown all nexthops going via it.
1331 */
1332 int fib_sync_down_addr(struct net *net, __be32 local)
1333 {
1334 int ret = 0;
1335 unsigned int hash = fib_laddr_hashfn(local);
1336 struct hlist_head *head = &fib_info_laddrhash[hash];
1337 struct fib_info *fi;
1338
1339 if (!fib_info_laddrhash || local == 0)
1340 return 0;
1341
1342 hlist_for_each_entry(fi, head, fib_lhash) {
1343 if (!net_eq(fi->fib_net, net))
1344 continue;
1345 if (fi->fib_prefsrc == local) {
1346 fi->fib_flags |= RTNH_F_DEAD;
1347 ret++;
1348 }
1349 }
1350 return ret;
1351 }
1352
1353 /* Event force Flags Description
1354 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1355 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1356 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1357 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1358 */
1359 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1360 {
1361 int ret = 0;
1362 int scope = RT_SCOPE_NOWHERE;
1363 struct fib_info *prev_fi = NULL;
1364 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1365 struct hlist_head *head = &fib_info_devhash[hash];
1366 struct fib_nh *nh;
1367
1368 if (force)
1369 scope = -1;
1370
1371 hlist_for_each_entry(nh, head, nh_hash) {
1372 struct fib_info *fi = nh->nh_parent;
1373 int dead;
1374
1375 BUG_ON(!fi->fib_nhs);
1376 if (nh->nh_dev != dev || fi == prev_fi)
1377 continue;
1378 prev_fi = fi;
1379 dead = 0;
1380 change_nexthops(fi) {
1381 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1382 dead++;
1383 else if (nexthop_nh->nh_dev == dev &&
1384 nexthop_nh->nh_scope != scope) {
1385 switch (event) {
1386 case NETDEV_DOWN:
1387 case NETDEV_UNREGISTER:
1388 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1389 /* fall through */
1390 case NETDEV_CHANGE:
1391 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1392 break;
1393 }
1394 dead++;
1395 }
1396 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1397 if (event == NETDEV_UNREGISTER &&
1398 nexthop_nh->nh_dev == dev) {
1399 dead = fi->fib_nhs;
1400 break;
1401 }
1402 #endif
1403 } endfor_nexthops(fi)
1404 if (dead == fi->fib_nhs) {
1405 switch (event) {
1406 case NETDEV_DOWN:
1407 case NETDEV_UNREGISTER:
1408 fi->fib_flags |= RTNH_F_DEAD;
1409 /* fall through */
1410 case NETDEV_CHANGE:
1411 fi->fib_flags |= RTNH_F_LINKDOWN;
1412 break;
1413 }
1414 ret++;
1415 }
1416
1417 fib_rebalance(fi);
1418 }
1419
1420 return ret;
1421 }
1422
1423 /* Must be invoked inside of an RCU protected region. */
1424 void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1425 {
1426 struct fib_info *fi = NULL, *last_resort = NULL;
1427 struct hlist_head *fa_head = res->fa_head;
1428 struct fib_table *tb = res->table;
1429 u8 slen = 32 - res->prefixlen;
1430 int order = -1, last_idx = -1;
1431 struct fib_alias *fa, *fa1 = NULL;
1432 u32 last_prio = res->fi->fib_priority;
1433 u8 last_tos = 0;
1434
1435 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1436 struct fib_info *next_fi = fa->fa_info;
1437
1438 if (fa->fa_slen != slen)
1439 continue;
1440 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1441 continue;
1442 if (fa->tb_id != tb->tb_id)
1443 continue;
1444 if (next_fi->fib_priority > last_prio &&
1445 fa->fa_tos == last_tos) {
1446 if (last_tos)
1447 continue;
1448 break;
1449 }
1450 if (next_fi->fib_flags & RTNH_F_DEAD)
1451 continue;
1452 last_tos = fa->fa_tos;
1453 last_prio = next_fi->fib_priority;
1454
1455 if (next_fi->fib_scope != res->scope ||
1456 fa->fa_type != RTN_UNICAST)
1457 continue;
1458 if (!next_fi->fib_nh[0].nh_gw ||
1459 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1460 continue;
1461
1462 fib_alias_accessed(fa);
1463
1464 if (!fi) {
1465 if (next_fi != res->fi)
1466 break;
1467 fa1 = fa;
1468 } else if (!fib_detect_death(fi, order, &last_resort,
1469 &last_idx, fa1->fa_default)) {
1470 fib_result_assign(res, fi);
1471 fa1->fa_default = order;
1472 goto out;
1473 }
1474 fi = next_fi;
1475 order++;
1476 }
1477
1478 if (order <= 0 || !fi) {
1479 if (fa1)
1480 fa1->fa_default = -1;
1481 goto out;
1482 }
1483
1484 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1485 fa1->fa_default)) {
1486 fib_result_assign(res, fi);
1487 fa1->fa_default = order;
1488 goto out;
1489 }
1490
1491 if (last_idx >= 0)
1492 fib_result_assign(res, last_resort);
1493 fa1->fa_default = last_idx;
1494 out:
1495 return;
1496 }
1497
1498 /*
1499 * Dead device goes up. We wake up dead nexthops.
1500 * It takes sense only on multipath routes.
1501 */
1502 int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1503 {
1504 struct fib_info *prev_fi;
1505 unsigned int hash;
1506 struct hlist_head *head;
1507 struct fib_nh *nh;
1508 int ret;
1509
1510 if (!(dev->flags & IFF_UP))
1511 return 0;
1512
1513 if (nh_flags & RTNH_F_DEAD) {
1514 unsigned int flags = dev_get_flags(dev);
1515
1516 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1517 nh_flags |= RTNH_F_LINKDOWN;
1518 }
1519
1520 prev_fi = NULL;
1521 hash = fib_devindex_hashfn(dev->ifindex);
1522 head = &fib_info_devhash[hash];
1523 ret = 0;
1524
1525 hlist_for_each_entry(nh, head, nh_hash) {
1526 struct fib_info *fi = nh->nh_parent;
1527 int alive;
1528
1529 BUG_ON(!fi->fib_nhs);
1530 if (nh->nh_dev != dev || fi == prev_fi)
1531 continue;
1532
1533 prev_fi = fi;
1534 alive = 0;
1535 change_nexthops(fi) {
1536 if (!(nexthop_nh->nh_flags & nh_flags)) {
1537 alive++;
1538 continue;
1539 }
1540 if (!nexthop_nh->nh_dev ||
1541 !(nexthop_nh->nh_dev->flags & IFF_UP))
1542 continue;
1543 if (nexthop_nh->nh_dev != dev ||
1544 !__in_dev_get_rtnl(dev))
1545 continue;
1546 alive++;
1547 nexthop_nh->nh_flags &= ~nh_flags;
1548 } endfor_nexthops(fi)
1549
1550 if (alive > 0) {
1551 fi->fib_flags &= ~nh_flags;
1552 ret++;
1553 }
1554
1555 fib_rebalance(fi);
1556 }
1557
1558 return ret;
1559 }
1560
1561 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1562
1563 void fib_select_multipath(struct fib_result *res, int hash)
1564 {
1565 struct fib_info *fi = res->fi;
1566
1567 for_nexthops(fi) {
1568 if (hash > atomic_read(&nh->nh_upper_bound))
1569 continue;
1570
1571 res->nh_sel = nhsel;
1572 return;
1573 } endfor_nexthops(fi);
1574
1575 /* Race condition: route has just become dead. */
1576 res->nh_sel = 0;
1577 }
1578 #endif
1579
1580 void fib_select_path(struct net *net, struct fib_result *res,
1581 struct flowi4 *fl4, int mp_hash)
1582 {
1583 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1584 if (res->fi->fib_nhs > 1 && fl4->flowi4_oif == 0) {
1585 if (mp_hash < 0)
1586 mp_hash = get_hash_from_flowi4(fl4) >> 1;
1587
1588 fib_select_multipath(res, mp_hash);
1589 }
1590 else
1591 #endif
1592 if (!res->prefixlen &&
1593 res->table->tb_num_default > 1 &&
1594 res->type == RTN_UNICAST && !fl4->flowi4_oif)
1595 fib_select_default(fl4, res);
1596
1597 if (!fl4->saddr)
1598 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1599 }
1600 EXPORT_SYMBOL_GPL(fib_select_path);
Linux kernel - Deliverables
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