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