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Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[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
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, &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 #endif
535
536 int fib_encap_match(struct net *net, u16 encap_type,
537 struct nlattr *encap,
538 int oif, const struct fib_nh *nh)
539 {
540 struct lwtunnel_state *lwtstate;
541 struct net_device *dev = NULL;
542 int ret;
543
544 if (encap_type == LWTUNNEL_ENCAP_NONE)
545 return 0;
546
547 if (oif)
548 dev = __dev_get_by_index(net, oif);
549 ret = lwtunnel_build_state(dev, encap_type,
550 encap, &lwtstate);
551 if (!ret)
552 return lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
553
554 return 0;
555 }
556
557 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
558 {
559 struct net *net = cfg->fc_nlinfo.nl_net;
560 #ifdef CONFIG_IP_ROUTE_MULTIPATH
561 struct rtnexthop *rtnh;
562 int remaining;
563 #endif
564
565 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
566 return 1;
567
568 if (cfg->fc_oif || cfg->fc_gw) {
569 if (cfg->fc_encap) {
570 if (fib_encap_match(net, cfg->fc_encap_type,
571 cfg->fc_encap, cfg->fc_oif,
572 fi->fib_nh))
573 return 1;
574 }
575 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
576 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
577 return 0;
578 return 1;
579 }
580
581 #ifdef CONFIG_IP_ROUTE_MULTIPATH
582 if (!cfg->fc_mp)
583 return 0;
584
585 rtnh = cfg->fc_mp;
586 remaining = cfg->fc_mp_len;
587
588 for_nexthops(fi) {
589 int attrlen;
590
591 if (!rtnh_ok(rtnh, remaining))
592 return -EINVAL;
593
594 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
595 return 1;
596
597 attrlen = rtnh_attrlen(rtnh);
598 if (attrlen > 0) {
599 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
600
601 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
602 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
603 return 1;
604 #ifdef CONFIG_IP_ROUTE_CLASSID
605 nla = nla_find(attrs, attrlen, RTA_FLOW);
606 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
607 return 1;
608 #endif
609 }
610
611 rtnh = rtnh_next(rtnh, &remaining);
612 } endfor_nexthops(fi);
613 #endif
614 return 0;
615 }
616
617
618 /*
619 * Picture
620 * -------
621 *
622 * Semantics of nexthop is very messy by historical reasons.
623 * We have to take into account, that:
624 * a) gateway can be actually local interface address,
625 * so that gatewayed route is direct.
626 * b) gateway must be on-link address, possibly
627 * described not by an ifaddr, but also by a direct route.
628 * c) If both gateway and interface are specified, they should not
629 * contradict.
630 * d) If we use tunnel routes, gateway could be not on-link.
631 *
632 * Attempt to reconcile all of these (alas, self-contradictory) conditions
633 * results in pretty ugly and hairy code with obscure logic.
634 *
635 * I chose to generalized it instead, so that the size
636 * of code does not increase practically, but it becomes
637 * much more general.
638 * Every prefix is assigned a "scope" value: "host" is local address,
639 * "link" is direct route,
640 * [ ... "site" ... "interior" ... ]
641 * and "universe" is true gateway route with global meaning.
642 *
643 * Every prefix refers to a set of "nexthop"s (gw, oif),
644 * where gw must have narrower scope. This recursion stops
645 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
646 * which means that gw is forced to be on link.
647 *
648 * Code is still hairy, but now it is apparently logically
649 * consistent and very flexible. F.e. as by-product it allows
650 * to co-exists in peace independent exterior and interior
651 * routing processes.
652 *
653 * Normally it looks as following.
654 *
655 * {universe prefix} -> (gw, oif) [scope link]
656 * |
657 * |-> {link prefix} -> (gw, oif) [scope local]
658 * |
659 * |-> {local prefix} (terminal node)
660 */
661 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
662 struct fib_nh *nh)
663 {
664 int err;
665 struct net *net;
666 struct net_device *dev;
667
668 net = cfg->fc_nlinfo.nl_net;
669 if (nh->nh_gw) {
670 struct fib_result res;
671
672 if (nh->nh_flags & RTNH_F_ONLINK) {
673
674 if (cfg->fc_scope >= RT_SCOPE_LINK)
675 return -EINVAL;
676 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
677 return -EINVAL;
678 dev = __dev_get_by_index(net, nh->nh_oif);
679 if (!dev)
680 return -ENODEV;
681 if (!(dev->flags & IFF_UP))
682 return -ENETDOWN;
683 if (!netif_carrier_ok(dev))
684 nh->nh_flags |= RTNH_F_LINKDOWN;
685 nh->nh_dev = dev;
686 dev_hold(dev);
687 nh->nh_scope = RT_SCOPE_LINK;
688 return 0;
689 }
690 rcu_read_lock();
691 {
692 struct flowi4 fl4 = {
693 .daddr = nh->nh_gw,
694 .flowi4_scope = cfg->fc_scope + 1,
695 .flowi4_oif = nh->nh_oif,
696 .flowi4_iif = LOOPBACK_IFINDEX,
697 };
698
699 /* It is not necessary, but requires a bit of thinking */
700 if (fl4.flowi4_scope < RT_SCOPE_LINK)
701 fl4.flowi4_scope = RT_SCOPE_LINK;
702 err = fib_lookup(net, &fl4, &res,
703 FIB_LOOKUP_IGNORE_LINKSTATE);
704 if (err) {
705 rcu_read_unlock();
706 return err;
707 }
708 }
709 err = -EINVAL;
710 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
711 goto out;
712 nh->nh_scope = res.scope;
713 nh->nh_oif = FIB_RES_OIF(res);
714 nh->nh_dev = dev = FIB_RES_DEV(res);
715 if (!dev)
716 goto out;
717 dev_hold(dev);
718 if (!netif_carrier_ok(dev))
719 nh->nh_flags |= RTNH_F_LINKDOWN;
720 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
721 } else {
722 struct in_device *in_dev;
723
724 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
725 return -EINVAL;
726
727 rcu_read_lock();
728 err = -ENODEV;
729 in_dev = inetdev_by_index(net, nh->nh_oif);
730 if (!in_dev)
731 goto out;
732 err = -ENETDOWN;
733 if (!(in_dev->dev->flags & IFF_UP))
734 goto out;
735 nh->nh_dev = in_dev->dev;
736 dev_hold(nh->nh_dev);
737 nh->nh_scope = RT_SCOPE_HOST;
738 if (!netif_carrier_ok(nh->nh_dev))
739 nh->nh_flags |= RTNH_F_LINKDOWN;
740 err = 0;
741 }
742 out:
743 rcu_read_unlock();
744 return err;
745 }
746
747 static inline unsigned int fib_laddr_hashfn(__be32 val)
748 {
749 unsigned int mask = (fib_info_hash_size - 1);
750
751 return ((__force u32)val ^
752 ((__force u32)val >> 7) ^
753 ((__force u32)val >> 14)) & mask;
754 }
755
756 static struct hlist_head *fib_info_hash_alloc(int bytes)
757 {
758 if (bytes <= PAGE_SIZE)
759 return kzalloc(bytes, GFP_KERNEL);
760 else
761 return (struct hlist_head *)
762 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
763 get_order(bytes));
764 }
765
766 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
767 {
768 if (!hash)
769 return;
770
771 if (bytes <= PAGE_SIZE)
772 kfree(hash);
773 else
774 free_pages((unsigned long) hash, get_order(bytes));
775 }
776
777 static void fib_info_hash_move(struct hlist_head *new_info_hash,
778 struct hlist_head *new_laddrhash,
779 unsigned int new_size)
780 {
781 struct hlist_head *old_info_hash, *old_laddrhash;
782 unsigned int old_size = fib_info_hash_size;
783 unsigned int i, bytes;
784
785 spin_lock_bh(&fib_info_lock);
786 old_info_hash = fib_info_hash;
787 old_laddrhash = fib_info_laddrhash;
788 fib_info_hash_size = new_size;
789
790 for (i = 0; i < old_size; i++) {
791 struct hlist_head *head = &fib_info_hash[i];
792 struct hlist_node *n;
793 struct fib_info *fi;
794
795 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
796 struct hlist_head *dest;
797 unsigned int new_hash;
798
799 new_hash = fib_info_hashfn(fi);
800 dest = &new_info_hash[new_hash];
801 hlist_add_head(&fi->fib_hash, dest);
802 }
803 }
804 fib_info_hash = new_info_hash;
805
806 for (i = 0; i < old_size; i++) {
807 struct hlist_head *lhead = &fib_info_laddrhash[i];
808 struct hlist_node *n;
809 struct fib_info *fi;
810
811 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
812 struct hlist_head *ldest;
813 unsigned int new_hash;
814
815 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
816 ldest = &new_laddrhash[new_hash];
817 hlist_add_head(&fi->fib_lhash, ldest);
818 }
819 }
820 fib_info_laddrhash = new_laddrhash;
821
822 spin_unlock_bh(&fib_info_lock);
823
824 bytes = old_size * sizeof(struct hlist_head *);
825 fib_info_hash_free(old_info_hash, bytes);
826 fib_info_hash_free(old_laddrhash, bytes);
827 }
828
829 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
830 {
831 nh->nh_saddr = inet_select_addr(nh->nh_dev,
832 nh->nh_gw,
833 nh->nh_parent->fib_scope);
834 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
835
836 return nh->nh_saddr;
837 }
838
839 struct fib_info *fib_create_info(struct fib_config *cfg)
840 {
841 int err;
842 struct fib_info *fi = NULL;
843 struct fib_info *ofi;
844 int nhs = 1;
845 struct net *net = cfg->fc_nlinfo.nl_net;
846
847 if (cfg->fc_type > RTN_MAX)
848 goto err_inval;
849
850 /* Fast check to catch the most weird cases */
851 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
852 goto err_inval;
853
854 #ifdef CONFIG_IP_ROUTE_MULTIPATH
855 if (cfg->fc_mp) {
856 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
857 if (nhs == 0)
858 goto err_inval;
859 }
860 #endif
861
862 err = -ENOBUFS;
863 if (fib_info_cnt >= fib_info_hash_size) {
864 unsigned int new_size = fib_info_hash_size << 1;
865 struct hlist_head *new_info_hash;
866 struct hlist_head *new_laddrhash;
867 unsigned int bytes;
868
869 if (!new_size)
870 new_size = 16;
871 bytes = new_size * sizeof(struct hlist_head *);
872 new_info_hash = fib_info_hash_alloc(bytes);
873 new_laddrhash = fib_info_hash_alloc(bytes);
874 if (!new_info_hash || !new_laddrhash) {
875 fib_info_hash_free(new_info_hash, bytes);
876 fib_info_hash_free(new_laddrhash, bytes);
877 } else
878 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
879
880 if (!fib_info_hash_size)
881 goto failure;
882 }
883
884 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
885 if (!fi)
886 goto failure;
887 fib_info_cnt++;
888 if (cfg->fc_mx) {
889 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
890 if (!fi->fib_metrics)
891 goto failure;
892 } else
893 fi->fib_metrics = (u32 *) dst_default_metrics;
894
895 fi->fib_net = net;
896 fi->fib_protocol = cfg->fc_protocol;
897 fi->fib_scope = cfg->fc_scope;
898 fi->fib_flags = cfg->fc_flags;
899 fi->fib_priority = cfg->fc_priority;
900 fi->fib_prefsrc = cfg->fc_prefsrc;
901 fi->fib_type = cfg->fc_type;
902
903 fi->fib_nhs = nhs;
904 change_nexthops(fi) {
905 nexthop_nh->nh_parent = fi;
906 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
907 if (!nexthop_nh->nh_pcpu_rth_output)
908 goto failure;
909 } endfor_nexthops(fi)
910
911 if (cfg->fc_mx) {
912 struct nlattr *nla;
913 int remaining;
914
915 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
916 int type = nla_type(nla);
917
918 if (type) {
919 u32 val;
920
921 if (type > RTAX_MAX)
922 goto err_inval;
923 if (type == RTAX_CC_ALGO) {
924 char tmp[TCP_CA_NAME_MAX];
925
926 nla_strlcpy(tmp, nla, sizeof(tmp));
927 val = tcp_ca_get_key_by_name(tmp);
928 if (val == TCP_CA_UNSPEC)
929 goto err_inval;
930 } else {
931 val = nla_get_u32(nla);
932 }
933 if (type == RTAX_ADVMSS && val > 65535 - 40)
934 val = 65535 - 40;
935 if (type == RTAX_MTU && val > 65535 - 15)
936 val = 65535 - 15;
937 fi->fib_metrics[type - 1] = val;
938 }
939 }
940 }
941
942 if (cfg->fc_mp) {
943 #ifdef CONFIG_IP_ROUTE_MULTIPATH
944 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
945 if (err != 0)
946 goto failure;
947 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
948 goto err_inval;
949 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
950 goto err_inval;
951 #ifdef CONFIG_IP_ROUTE_CLASSID
952 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
953 goto err_inval;
954 #endif
955 #else
956 goto err_inval;
957 #endif
958 } else {
959 struct fib_nh *nh = fi->fib_nh;
960
961 if (cfg->fc_encap) {
962 struct lwtunnel_state *lwtstate;
963 struct net_device *dev = NULL;
964
965 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE)
966 goto err_inval;
967 if (cfg->fc_oif)
968 dev = __dev_get_by_index(net, cfg->fc_oif);
969 err = lwtunnel_build_state(dev, cfg->fc_encap_type,
970 cfg->fc_encap, &lwtstate);
971 if (err)
972 goto failure;
973
974 nh->nh_lwtstate = lwtstate_get(lwtstate);
975 }
976 nh->nh_oif = cfg->fc_oif;
977 nh->nh_gw = cfg->fc_gw;
978 nh->nh_flags = cfg->fc_flags;
979 #ifdef CONFIG_IP_ROUTE_CLASSID
980 nh->nh_tclassid = cfg->fc_flow;
981 if (nh->nh_tclassid)
982 fi->fib_net->ipv4.fib_num_tclassid_users++;
983 #endif
984 #ifdef CONFIG_IP_ROUTE_MULTIPATH
985 nh->nh_weight = 1;
986 #endif
987 }
988
989 if (fib_props[cfg->fc_type].error) {
990 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
991 goto err_inval;
992 goto link_it;
993 } else {
994 switch (cfg->fc_type) {
995 case RTN_UNICAST:
996 case RTN_LOCAL:
997 case RTN_BROADCAST:
998 case RTN_ANYCAST:
999 case RTN_MULTICAST:
1000 break;
1001 default:
1002 goto err_inval;
1003 }
1004 }
1005
1006 if (cfg->fc_scope > RT_SCOPE_HOST)
1007 goto err_inval;
1008
1009 if (cfg->fc_scope == RT_SCOPE_HOST) {
1010 struct fib_nh *nh = fi->fib_nh;
1011
1012 /* Local address is added. */
1013 if (nhs != 1 || nh->nh_gw)
1014 goto err_inval;
1015 nh->nh_scope = RT_SCOPE_NOWHERE;
1016 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1017 err = -ENODEV;
1018 if (!nh->nh_dev)
1019 goto failure;
1020 } else {
1021 int linkdown = 0;
1022
1023 change_nexthops(fi) {
1024 err = fib_check_nh(cfg, fi, nexthop_nh);
1025 if (err != 0)
1026 goto failure;
1027 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1028 linkdown++;
1029 } endfor_nexthops(fi)
1030 if (linkdown == fi->fib_nhs)
1031 fi->fib_flags |= RTNH_F_LINKDOWN;
1032 }
1033
1034 if (fi->fib_prefsrc) {
1035 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1036 fi->fib_prefsrc != cfg->fc_dst)
1037 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
1038 goto err_inval;
1039 }
1040
1041 change_nexthops(fi) {
1042 fib_info_update_nh_saddr(net, nexthop_nh);
1043 } endfor_nexthops(fi)
1044
1045 link_it:
1046 ofi = fib_find_info(fi);
1047 if (ofi) {
1048 fi->fib_dead = 1;
1049 free_fib_info(fi);
1050 ofi->fib_treeref++;
1051 return ofi;
1052 }
1053
1054 fi->fib_treeref++;
1055 atomic_inc(&fi->fib_clntref);
1056 spin_lock_bh(&fib_info_lock);
1057 hlist_add_head(&fi->fib_hash,
1058 &fib_info_hash[fib_info_hashfn(fi)]);
1059 if (fi->fib_prefsrc) {
1060 struct hlist_head *head;
1061
1062 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1063 hlist_add_head(&fi->fib_lhash, head);
1064 }
1065 change_nexthops(fi) {
1066 struct hlist_head *head;
1067 unsigned int hash;
1068
1069 if (!nexthop_nh->nh_dev)
1070 continue;
1071 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1072 head = &fib_info_devhash[hash];
1073 hlist_add_head(&nexthop_nh->nh_hash, head);
1074 } endfor_nexthops(fi)
1075 spin_unlock_bh(&fib_info_lock);
1076 return fi;
1077
1078 err_inval:
1079 err = -EINVAL;
1080
1081 failure:
1082 if (fi) {
1083 fi->fib_dead = 1;
1084 free_fib_info(fi);
1085 }
1086
1087 return ERR_PTR(err);
1088 }
1089
1090 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1091 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1092 struct fib_info *fi, unsigned int flags)
1093 {
1094 struct nlmsghdr *nlh;
1095 struct rtmsg *rtm;
1096
1097 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1098 if (!nlh)
1099 return -EMSGSIZE;
1100
1101 rtm = nlmsg_data(nlh);
1102 rtm->rtm_family = AF_INET;
1103 rtm->rtm_dst_len = dst_len;
1104 rtm->rtm_src_len = 0;
1105 rtm->rtm_tos = tos;
1106 if (tb_id < 256)
1107 rtm->rtm_table = tb_id;
1108 else
1109 rtm->rtm_table = RT_TABLE_COMPAT;
1110 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1111 goto nla_put_failure;
1112 rtm->rtm_type = type;
1113 rtm->rtm_flags = fi->fib_flags;
1114 rtm->rtm_scope = fi->fib_scope;
1115 rtm->rtm_protocol = fi->fib_protocol;
1116
1117 if (rtm->rtm_dst_len &&
1118 nla_put_in_addr(skb, RTA_DST, dst))
1119 goto nla_put_failure;
1120 if (fi->fib_priority &&
1121 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1122 goto nla_put_failure;
1123 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
1124 goto nla_put_failure;
1125
1126 if (fi->fib_prefsrc &&
1127 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1128 goto nla_put_failure;
1129 if (fi->fib_nhs == 1) {
1130 struct in_device *in_dev;
1131
1132 if (fi->fib_nh->nh_gw &&
1133 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1134 goto nla_put_failure;
1135 if (fi->fib_nh->nh_oif &&
1136 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1137 goto nla_put_failure;
1138 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1139 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev);
1140 if (in_dev &&
1141 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1142 rtm->rtm_flags |= RTNH_F_DEAD;
1143 }
1144 #ifdef CONFIG_IP_ROUTE_CLASSID
1145 if (fi->fib_nh[0].nh_tclassid &&
1146 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1147 goto nla_put_failure;
1148 #endif
1149 if (fi->fib_nh->nh_lwtstate)
1150 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate);
1151 }
1152 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1153 if (fi->fib_nhs > 1) {
1154 struct rtnexthop *rtnh;
1155 struct nlattr *mp;
1156
1157 mp = nla_nest_start(skb, RTA_MULTIPATH);
1158 if (!mp)
1159 goto nla_put_failure;
1160
1161 for_nexthops(fi) {
1162 struct in_device *in_dev;
1163
1164 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1165 if (!rtnh)
1166 goto nla_put_failure;
1167
1168 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1169 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1170 in_dev = __in_dev_get_rtnl(nh->nh_dev);
1171 if (in_dev &&
1172 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1173 rtnh->rtnh_flags |= RTNH_F_DEAD;
1174 }
1175 rtnh->rtnh_hops = nh->nh_weight - 1;
1176 rtnh->rtnh_ifindex = nh->nh_oif;
1177
1178 if (nh->nh_gw &&
1179 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1180 goto nla_put_failure;
1181 #ifdef CONFIG_IP_ROUTE_CLASSID
1182 if (nh->nh_tclassid &&
1183 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1184 goto nla_put_failure;
1185 #endif
1186 if (nh->nh_lwtstate)
1187 lwtunnel_fill_encap(skb, nh->nh_lwtstate);
1188 /* length of rtnetlink header + attributes */
1189 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1190 } endfor_nexthops(fi);
1191
1192 nla_nest_end(skb, mp);
1193 }
1194 #endif
1195 nlmsg_end(skb, nlh);
1196 return 0;
1197
1198 nla_put_failure:
1199 nlmsg_cancel(skb, nlh);
1200 return -EMSGSIZE;
1201 }
1202
1203 /*
1204 * Update FIB if:
1205 * - local address disappeared -> we must delete all the entries
1206 * referring to it.
1207 * - device went down -> we must shutdown all nexthops going via it.
1208 */
1209 int fib_sync_down_addr(struct net *net, __be32 local)
1210 {
1211 int ret = 0;
1212 unsigned int hash = fib_laddr_hashfn(local);
1213 struct hlist_head *head = &fib_info_laddrhash[hash];
1214 struct fib_info *fi;
1215
1216 if (!fib_info_laddrhash || local == 0)
1217 return 0;
1218
1219 hlist_for_each_entry(fi, head, fib_lhash) {
1220 if (!net_eq(fi->fib_net, net))
1221 continue;
1222 if (fi->fib_prefsrc == local) {
1223 fi->fib_flags |= RTNH_F_DEAD;
1224 ret++;
1225 }
1226 }
1227 return ret;
1228 }
1229
1230 int fib_sync_down_dev(struct net_device *dev, unsigned long event)
1231 {
1232 int ret = 0;
1233 int scope = RT_SCOPE_NOWHERE;
1234 struct fib_info *prev_fi = NULL;
1235 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1236 struct hlist_head *head = &fib_info_devhash[hash];
1237 struct fib_nh *nh;
1238
1239 if (event == NETDEV_UNREGISTER ||
1240 event == NETDEV_DOWN)
1241 scope = -1;
1242
1243 hlist_for_each_entry(nh, head, nh_hash) {
1244 struct fib_info *fi = nh->nh_parent;
1245 int dead;
1246
1247 BUG_ON(!fi->fib_nhs);
1248 if (nh->nh_dev != dev || fi == prev_fi)
1249 continue;
1250 prev_fi = fi;
1251 dead = 0;
1252 change_nexthops(fi) {
1253 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1254 dead++;
1255 else if (nexthop_nh->nh_dev == dev &&
1256 nexthop_nh->nh_scope != scope) {
1257 switch (event) {
1258 case NETDEV_DOWN:
1259 case NETDEV_UNREGISTER:
1260 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1261 /* fall through */
1262 case NETDEV_CHANGE:
1263 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1264 break;
1265 }
1266 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1267 spin_lock_bh(&fib_multipath_lock);
1268 fi->fib_power -= nexthop_nh->nh_power;
1269 nexthop_nh->nh_power = 0;
1270 spin_unlock_bh(&fib_multipath_lock);
1271 #endif
1272 dead++;
1273 }
1274 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1275 if (event == NETDEV_UNREGISTER &&
1276 nexthop_nh->nh_dev == dev) {
1277 dead = fi->fib_nhs;
1278 break;
1279 }
1280 #endif
1281 } endfor_nexthops(fi)
1282 if (dead == fi->fib_nhs) {
1283 switch (event) {
1284 case NETDEV_DOWN:
1285 case NETDEV_UNREGISTER:
1286 fi->fib_flags |= RTNH_F_DEAD;
1287 /* fall through */
1288 case NETDEV_CHANGE:
1289 fi->fib_flags |= RTNH_F_LINKDOWN;
1290 break;
1291 }
1292 ret++;
1293 }
1294 }
1295
1296 return ret;
1297 }
1298
1299 /* Must be invoked inside of an RCU protected region. */
1300 void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1301 {
1302 struct fib_info *fi = NULL, *last_resort = NULL;
1303 struct hlist_head *fa_head = res->fa_head;
1304 struct fib_table *tb = res->table;
1305 u8 slen = 32 - res->prefixlen;
1306 int order = -1, last_idx = -1;
1307 struct fib_alias *fa, *fa1 = NULL;
1308 u32 last_prio = res->fi->fib_priority;
1309 u8 last_tos = 0;
1310
1311 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1312 struct fib_info *next_fi = fa->fa_info;
1313
1314 if (fa->fa_slen != slen)
1315 continue;
1316 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1317 continue;
1318 if (fa->tb_id != tb->tb_id)
1319 continue;
1320 if (next_fi->fib_priority > last_prio &&
1321 fa->fa_tos == last_tos) {
1322 if (last_tos)
1323 continue;
1324 break;
1325 }
1326 if (next_fi->fib_flags & RTNH_F_DEAD)
1327 continue;
1328 last_tos = fa->fa_tos;
1329 last_prio = next_fi->fib_priority;
1330
1331 if (next_fi->fib_scope != res->scope ||
1332 fa->fa_type != RTN_UNICAST)
1333 continue;
1334 if (!next_fi->fib_nh[0].nh_gw ||
1335 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1336 continue;
1337
1338 fib_alias_accessed(fa);
1339
1340 if (!fi) {
1341 if (next_fi != res->fi)
1342 break;
1343 fa1 = fa;
1344 } else if (!fib_detect_death(fi, order, &last_resort,
1345 &last_idx, fa1->fa_default)) {
1346 fib_result_assign(res, fi);
1347 fa1->fa_default = order;
1348 goto out;
1349 }
1350 fi = next_fi;
1351 order++;
1352 }
1353
1354 if (order <= 0 || !fi) {
1355 if (fa1)
1356 fa1->fa_default = -1;
1357 goto out;
1358 }
1359
1360 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1361 fa1->fa_default)) {
1362 fib_result_assign(res, fi);
1363 fa1->fa_default = order;
1364 goto out;
1365 }
1366
1367 if (last_idx >= 0)
1368 fib_result_assign(res, last_resort);
1369 fa1->fa_default = last_idx;
1370 out:
1371 return;
1372 }
1373
1374 /*
1375 * Dead device goes up. We wake up dead nexthops.
1376 * It takes sense only on multipath routes.
1377 */
1378 int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1379 {
1380 struct fib_info *prev_fi;
1381 unsigned int hash;
1382 struct hlist_head *head;
1383 struct fib_nh *nh;
1384 int ret;
1385
1386 if (!(dev->flags & IFF_UP))
1387 return 0;
1388
1389 prev_fi = NULL;
1390 hash = fib_devindex_hashfn(dev->ifindex);
1391 head = &fib_info_devhash[hash];
1392 ret = 0;
1393
1394 hlist_for_each_entry(nh, head, nh_hash) {
1395 struct fib_info *fi = nh->nh_parent;
1396 int alive;
1397
1398 BUG_ON(!fi->fib_nhs);
1399 if (nh->nh_dev != dev || fi == prev_fi)
1400 continue;
1401
1402 prev_fi = fi;
1403 alive = 0;
1404 change_nexthops(fi) {
1405 if (!(nexthop_nh->nh_flags & nh_flags)) {
1406 alive++;
1407 continue;
1408 }
1409 if (!nexthop_nh->nh_dev ||
1410 !(nexthop_nh->nh_dev->flags & IFF_UP))
1411 continue;
1412 if (nexthop_nh->nh_dev != dev ||
1413 !__in_dev_get_rtnl(dev))
1414 continue;
1415 alive++;
1416 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1417 spin_lock_bh(&fib_multipath_lock);
1418 nexthop_nh->nh_power = 0;
1419 nexthop_nh->nh_flags &= ~nh_flags;
1420 spin_unlock_bh(&fib_multipath_lock);
1421 #else
1422 nexthop_nh->nh_flags &= ~nh_flags;
1423 #endif
1424 } endfor_nexthops(fi)
1425
1426 if (alive > 0) {
1427 fi->fib_flags &= ~nh_flags;
1428 ret++;
1429 }
1430 }
1431
1432 return ret;
1433 }
1434
1435 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1436
1437 /*
1438 * The algorithm is suboptimal, but it provides really
1439 * fair weighted route distribution.
1440 */
1441 void fib_select_multipath(struct fib_result *res)
1442 {
1443 struct fib_info *fi = res->fi;
1444 struct in_device *in_dev;
1445 int w;
1446
1447 spin_lock_bh(&fib_multipath_lock);
1448 if (fi->fib_power <= 0) {
1449 int power = 0;
1450 change_nexthops(fi) {
1451 in_dev = __in_dev_get_rcu(nexthop_nh->nh_dev);
1452 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1453 continue;
1454 if (in_dev &&
1455 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
1456 nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1457 continue;
1458 power += nexthop_nh->nh_weight;
1459 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1460 } endfor_nexthops(fi);
1461 fi->fib_power = power;
1462 if (power <= 0) {
1463 spin_unlock_bh(&fib_multipath_lock);
1464 /* Race condition: route has just become dead. */
1465 res->nh_sel = 0;
1466 return;
1467 }
1468 }
1469
1470
1471 /* w should be random number [0..fi->fib_power-1],
1472 * it is pretty bad approximation.
1473 */
1474
1475 w = jiffies % fi->fib_power;
1476
1477 change_nexthops(fi) {
1478 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1479 nexthop_nh->nh_power) {
1480 w -= nexthop_nh->nh_power;
1481 if (w <= 0) {
1482 nexthop_nh->nh_power--;
1483 fi->fib_power--;
1484 res->nh_sel = nhsel;
1485 spin_unlock_bh(&fib_multipath_lock);
1486 return;
1487 }
1488 }
1489 } endfor_nexthops(fi);
1490
1491 /* Race condition: route has just become dead. */
1492 res->nh_sel = 0;
1493 spin_unlock_bh(&fib_multipath_lock);
1494 }
1495 #endif
Linux kernel - Deliverables
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