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ALSA: usb-audio: Fix an out-of-bound read in create_composite_quirks
[linux/fpc-iii.git] / net / ipv4 / fib_semantics.c
blob3109b9bb95d20e96f1ee3ff9cdc4acfde26abc7c
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 struct dst_metrics *m;
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 m = fi->fib_metrics;
219 if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt))
220 kfree(m);
221 kfree(fi);
222 }
223
224 void free_fib_info(struct fib_info *fi)
225 {
226 if (fi->fib_dead == 0) {
227 pr_warn("Freeing alive fib_info %p\n", fi);
228 return;
229 }
230 fib_info_cnt--;
231 #ifdef CONFIG_IP_ROUTE_CLASSID
232 change_nexthops(fi) {
233 if (nexthop_nh->nh_tclassid)
234 fi->fib_net->ipv4.fib_num_tclassid_users--;
235 } endfor_nexthops(fi);
236 #endif
237 call_rcu(&fi->rcu, free_fib_info_rcu);
238 }
239
240 void fib_release_info(struct fib_info *fi)
241 {
242 spin_lock_bh(&fib_info_lock);
243 if (fi && --fi->fib_treeref == 0) {
244 hlist_del(&fi->fib_hash);
245 if (fi->fib_prefsrc)
246 hlist_del(&fi->fib_lhash);
247 change_nexthops(fi) {
248 if (!nexthop_nh->nh_dev)
249 continue;
250 hlist_del(&nexthop_nh->nh_hash);
251 } endfor_nexthops(fi)
252 fi->fib_dead = 1;
253 fib_info_put(fi);
254 }
255 spin_unlock_bh(&fib_info_lock);
256 }
257
258 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
259 {
260 const struct fib_nh *onh = ofi->fib_nh;
261
262 for_nexthops(fi) {
263 if (nh->nh_oif != onh->nh_oif ||
264 nh->nh_gw != onh->nh_gw ||
265 nh->nh_scope != onh->nh_scope ||
266 #ifdef CONFIG_IP_ROUTE_MULTIPATH
267 nh->nh_weight != onh->nh_weight ||
268 #endif
269 #ifdef CONFIG_IP_ROUTE_CLASSID
270 nh->nh_tclassid != onh->nh_tclassid ||
271 #endif
272 lwtunnel_cmp_encap(nh->nh_lwtstate, onh->nh_lwtstate) ||
273 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_COMPARE_MASK))
274 return -1;
275 onh++;
276 } endfor_nexthops(fi);
277 return 0;
278 }
279
280 static inline unsigned int fib_devindex_hashfn(unsigned int val)
281 {
282 unsigned int mask = DEVINDEX_HASHSIZE - 1;
283
284 return (val ^
285 (val >> DEVINDEX_HASHBITS) ^
286 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
287 }
288
289 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
290 {
291 unsigned int mask = (fib_info_hash_size - 1);
292 unsigned int val = fi->fib_nhs;
293
294 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
295 val ^= (__force u32)fi->fib_prefsrc;
296 val ^= fi->fib_priority;
297 for_nexthops(fi) {
298 val ^= fib_devindex_hashfn(nh->nh_oif);
299 } endfor_nexthops(fi)
300
301 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
302 }
303
304 static struct fib_info *fib_find_info(const struct fib_info *nfi)
305 {
306 struct hlist_head *head;
307 struct fib_info *fi;
308 unsigned int hash;
309
310 hash = fib_info_hashfn(nfi);
311 head = &fib_info_hash[hash];
312
313 hlist_for_each_entry(fi, head, fib_hash) {
314 if (!net_eq(fi->fib_net, nfi->fib_net))
315 continue;
316 if (fi->fib_nhs != nfi->fib_nhs)
317 continue;
318 if (nfi->fib_protocol == fi->fib_protocol &&
319 nfi->fib_scope == fi->fib_scope &&
320 nfi->fib_prefsrc == fi->fib_prefsrc &&
321 nfi->fib_priority == fi->fib_priority &&
322 nfi->fib_type == fi->fib_type &&
323 memcmp(nfi->fib_metrics, fi->fib_metrics,
324 sizeof(u32) * RTAX_MAX) == 0 &&
325 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
326 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
327 return fi;
328 }
329
330 return NULL;
331 }
332
333 /* Check, that the gateway is already configured.
334 * Used only by redirect accept routine.
335 */
336 int ip_fib_check_default(__be32 gw, struct net_device *dev)
337 {
338 struct hlist_head *head;
339 struct fib_nh *nh;
340 unsigned int hash;
341
342 spin_lock(&fib_info_lock);
343
344 hash = fib_devindex_hashfn(dev->ifindex);
345 head = &fib_info_devhash[hash];
346 hlist_for_each_entry(nh, head, nh_hash) {
347 if (nh->nh_dev == dev &&
348 nh->nh_gw == gw &&
349 !(nh->nh_flags & RTNH_F_DEAD)) {
350 spin_unlock(&fib_info_lock);
351 return 0;
352 }
353 }
354
355 spin_unlock(&fib_info_lock);
356
357 return -1;
358 }
359
360 static inline size_t fib_nlmsg_size(struct fib_info *fi)
361 {
362 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
363 + nla_total_size(4) /* RTA_TABLE */
364 + nla_total_size(4) /* RTA_DST */
365 + nla_total_size(4) /* RTA_PRIORITY */
366 + nla_total_size(4) /* RTA_PREFSRC */
367 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
368
369 /* space for nested metrics */
370 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
371
372 if (fi->fib_nhs) {
373 size_t nh_encapsize = 0;
374 /* Also handles the special case fib_nhs == 1 */
375
376 /* each nexthop is packed in an attribute */
377 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
378
379 /* may contain flow and gateway attribute */
380 nhsize += 2 * nla_total_size(4);
381
382 /* grab encap info */
383 for_nexthops(fi) {
384 if (nh->nh_lwtstate) {
385 /* RTA_ENCAP_TYPE */
386 nh_encapsize += lwtunnel_get_encap_size(
387 nh->nh_lwtstate);
388 /* RTA_ENCAP */
389 nh_encapsize += nla_total_size(2);
390 }
391 } endfor_nexthops(fi);
392
393 /* all nexthops are packed in a nested attribute */
394 payload += nla_total_size((fi->fib_nhs * nhsize) +
395 nh_encapsize);
396
397 }
398
399 return payload;
400 }
401
402 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
403 int dst_len, u32 tb_id, const struct nl_info *info,
404 unsigned int nlm_flags)
405 {
406 struct sk_buff *skb;
407 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
408 int err = -ENOBUFS;
409
410 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
411 if (!skb)
412 goto errout;
413
414 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
415 fa->fa_type, key, dst_len,
416 fa->fa_tos, fa->fa_info, nlm_flags);
417 if (err < 0) {
418 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
419 WARN_ON(err == -EMSGSIZE);
420 kfree_skb(skb);
421 goto errout;
422 }
423 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
424 info->nlh, GFP_KERNEL);
425 return;
426 errout:
427 if (err < 0)
428 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
429 }
430
431 static int fib_detect_death(struct fib_info *fi, int order,
432 struct fib_info **last_resort, int *last_idx,
433 int dflt)
434 {
435 struct neighbour *n;
436 int state = NUD_NONE;
437
438 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
439 if (n) {
440 state = n->nud_state;
441 neigh_release(n);
442 } else {
443 return 0;
444 }
445 if (state == NUD_REACHABLE)
446 return 0;
447 if ((state & NUD_VALID) && order != dflt)
448 return 0;
449 if ((state & NUD_VALID) ||
450 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
451 *last_resort = fi;
452 *last_idx = order;
453 }
454 return 1;
455 }
456
457 #ifdef CONFIG_IP_ROUTE_MULTIPATH
458
459 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
460 {
461 int nhs = 0;
462
463 while (rtnh_ok(rtnh, remaining)) {
464 nhs++;
465 rtnh = rtnh_next(rtnh, &remaining);
466 }
467
468 /* leftover implies invalid nexthop configuration, discard it */
469 return remaining > 0 ? 0 : nhs;
470 }
471
472 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
473 int remaining, struct fib_config *cfg)
474 {
475 struct net *net = cfg->fc_nlinfo.nl_net;
476 int ret;
477
478 change_nexthops(fi) {
479 int attrlen;
480
481 if (!rtnh_ok(rtnh, remaining))
482 return -EINVAL;
483
484 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
485 return -EINVAL;
486
487 nexthop_nh->nh_flags =
488 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
489 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
490 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
491
492 attrlen = rtnh_attrlen(rtnh);
493 if (attrlen > 0) {
494 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
495
496 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
497 nexthop_nh->nh_gw = nla ? nla_get_in_addr(nla) : 0;
498 #ifdef CONFIG_IP_ROUTE_CLASSID
499 nla = nla_find(attrs, attrlen, RTA_FLOW);
500 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
501 if (nexthop_nh->nh_tclassid)
502 fi->fib_net->ipv4.fib_num_tclassid_users++;
503 #endif
504 nla = nla_find(attrs, attrlen, RTA_ENCAP);
505 if (nla) {
506 struct lwtunnel_state *lwtstate;
507 struct net_device *dev = NULL;
508 struct nlattr *nla_entype;
509
510 nla_entype = nla_find(attrs, attrlen,
511 RTA_ENCAP_TYPE);
512 if (!nla_entype)
513 goto err_inval;
514 if (cfg->fc_oif)
515 dev = __dev_get_by_index(net, cfg->fc_oif);
516 ret = lwtunnel_build_state(dev, nla_get_u16(
517 nla_entype),
518 nla, AF_INET, cfg,
519 &lwtstate);
520 if (ret)
521 goto errout;
522 nexthop_nh->nh_lwtstate =
523 lwtstate_get(lwtstate);
524 }
525 }
526
527 rtnh = rtnh_next(rtnh, &remaining);
528 } endfor_nexthops(fi);
529
530 return 0;
531
532 err_inval:
533 ret = -EINVAL;
534
535 errout:
536 return ret;
537 }
538
539 static void fib_rebalance(struct fib_info *fi)
540 {
541 int total;
542 int w;
543 struct in_device *in_dev;
544
545 if (fi->fib_nhs < 2)
546 return;
547
548 total = 0;
549 for_nexthops(fi) {
550 if (nh->nh_flags & RTNH_F_DEAD)
551 continue;
552
553 in_dev = __in_dev_get_rtnl(nh->nh_dev);
554
555 if (in_dev &&
556 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
557 nh->nh_flags & RTNH_F_LINKDOWN)
558 continue;
559
560 total += nh->nh_weight;
561 } endfor_nexthops(fi);
562
563 w = 0;
564 change_nexthops(fi) {
565 int upper_bound;
566
567 in_dev = __in_dev_get_rtnl(nexthop_nh->nh_dev);
568
569 if (nexthop_nh->nh_flags & RTNH_F_DEAD) {
570 upper_bound = -1;
571 } else if (in_dev &&
572 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) &&
573 nexthop_nh->nh_flags & RTNH_F_LINKDOWN) {
574 upper_bound = -1;
575 } else {
576 w += nexthop_nh->nh_weight;
577 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
578 total) - 1;
579 }
580
581 atomic_set(&nexthop_nh->nh_upper_bound, upper_bound);
582 } endfor_nexthops(fi);
583
584 net_get_random_once(&fib_multipath_secret,
585 sizeof(fib_multipath_secret));
586 }
587
588 static inline void fib_add_weight(struct fib_info *fi,
589 const struct fib_nh *nh)
590 {
591 fi->fib_weight += nh->nh_weight;
592 }
593
594 #else /* CONFIG_IP_ROUTE_MULTIPATH */
595
596 #define fib_rebalance(fi) do { } while (0)
597 #define fib_add_weight(fi, nh) do { } while (0)
598
599 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
600
601 static int fib_encap_match(struct net *net, u16 encap_type,
602 struct nlattr *encap,
603 int oif, const struct fib_nh *nh,
604 const struct fib_config *cfg)
605 {
606 struct lwtunnel_state *lwtstate;
607 struct net_device *dev = NULL;
608 int ret, result = 0;
609
610 if (encap_type == LWTUNNEL_ENCAP_NONE)
611 return 0;
612
613 if (oif)
614 dev = __dev_get_by_index(net, oif);
615 ret = lwtunnel_build_state(dev, encap_type, encap,
616 AF_INET, cfg, &lwtstate);
617 if (!ret) {
618 result = lwtunnel_cmp_encap(lwtstate, nh->nh_lwtstate);
619 lwtstate_free(lwtstate);
620 }
621
622 return result;
623 }
624
625 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
626 {
627 struct net *net = cfg->fc_nlinfo.nl_net;
628 #ifdef CONFIG_IP_ROUTE_MULTIPATH
629 struct rtnexthop *rtnh;
630 int remaining;
631 #endif
632
633 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
634 return 1;
635
636 if (cfg->fc_oif || cfg->fc_gw) {
637 if (cfg->fc_encap) {
638 if (fib_encap_match(net, cfg->fc_encap_type,
639 cfg->fc_encap, cfg->fc_oif,
640 fi->fib_nh, cfg))
641 return 1;
642 }
643 #ifdef CONFIG_IP_ROUTE_CLASSID
644 if (cfg->fc_flow &&
645 cfg->fc_flow != fi->fib_nh->nh_tclassid)
646 return 1;
647 #endif
648 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
649 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
650 return 0;
651 return 1;
652 }
653
654 #ifdef CONFIG_IP_ROUTE_MULTIPATH
655 if (!cfg->fc_mp)
656 return 0;
657
658 rtnh = cfg->fc_mp;
659 remaining = cfg->fc_mp_len;
660
661 for_nexthops(fi) {
662 int attrlen;
663
664 if (!rtnh_ok(rtnh, remaining))
665 return -EINVAL;
666
667 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
668 return 1;
669
670 attrlen = rtnh_attrlen(rtnh);
671 if (attrlen > 0) {
672 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
673
674 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
675 if (nla && nla_get_in_addr(nla) != nh->nh_gw)
676 return 1;
677 #ifdef CONFIG_IP_ROUTE_CLASSID
678 nla = nla_find(attrs, attrlen, RTA_FLOW);
679 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
680 return 1;
681 #endif
682 }
683
684 rtnh = rtnh_next(rtnh, &remaining);
685 } endfor_nexthops(fi);
686 #endif
687 return 0;
688 }
689
690
691 /*
692 * Picture
693 * -------
694 *
695 * Semantics of nexthop is very messy by historical reasons.
696 * We have to take into account, that:
697 * a) gateway can be actually local interface address,
698 * so that gatewayed route is direct.
699 * b) gateway must be on-link address, possibly
700 * described not by an ifaddr, but also by a direct route.
701 * c) If both gateway and interface are specified, they should not
702 * contradict.
703 * d) If we use tunnel routes, gateway could be not on-link.
704 *
705 * Attempt to reconcile all of these (alas, self-contradictory) conditions
706 * results in pretty ugly and hairy code with obscure logic.
707 *
708 * I chose to generalized it instead, so that the size
709 * of code does not increase practically, but it becomes
710 * much more general.
711 * Every prefix is assigned a "scope" value: "host" is local address,
712 * "link" is direct route,
713 * [ ... "site" ... "interior" ... ]
714 * and "universe" is true gateway route with global meaning.
715 *
716 * Every prefix refers to a set of "nexthop"s (gw, oif),
717 * where gw must have narrower scope. This recursion stops
718 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
719 * which means that gw is forced to be on link.
720 *
721 * Code is still hairy, but now it is apparently logically
722 * consistent and very flexible. F.e. as by-product it allows
723 * to co-exists in peace independent exterior and interior
724 * routing processes.
725 *
726 * Normally it looks as following.
727 *
728 * {universe prefix} -> (gw, oif) [scope link]
729 * |
730 * |-> {link prefix} -> (gw, oif) [scope local]
731 * |
732 * |-> {local prefix} (terminal node)
733 */
734 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
735 struct fib_nh *nh)
736 {
737 int err = 0;
738 struct net *net;
739 struct net_device *dev;
740
741 net = cfg->fc_nlinfo.nl_net;
742 if (nh->nh_gw) {
743 struct fib_result res;
744
745 if (nh->nh_flags & RTNH_F_ONLINK) {
746 unsigned int addr_type;
747
748 if (cfg->fc_scope >= RT_SCOPE_LINK)
749 return -EINVAL;
750 dev = __dev_get_by_index(net, nh->nh_oif);
751 if (!dev)
752 return -ENODEV;
753 if (!(dev->flags & IFF_UP))
754 return -ENETDOWN;
755 addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
756 if (addr_type != RTN_UNICAST)
757 return -EINVAL;
758 if (!netif_carrier_ok(dev))
759 nh->nh_flags |= RTNH_F_LINKDOWN;
760 nh->nh_dev = dev;
761 dev_hold(dev);
762 nh->nh_scope = RT_SCOPE_LINK;
763 return 0;
764 }
765 rcu_read_lock();
766 {
767 struct fib_table *tbl = NULL;
768 struct flowi4 fl4 = {
769 .daddr = nh->nh_gw,
770 .flowi4_scope = cfg->fc_scope + 1,
771 .flowi4_oif = nh->nh_oif,
772 .flowi4_iif = LOOPBACK_IFINDEX,
773 };
774
775 /* It is not necessary, but requires a bit of thinking */
776 if (fl4.flowi4_scope < RT_SCOPE_LINK)
777 fl4.flowi4_scope = RT_SCOPE_LINK;
778
779 if (cfg->fc_table)
780 tbl = fib_get_table(net, cfg->fc_table);
781
782 if (tbl)
783 err = fib_table_lookup(tbl, &fl4, &res,
784 FIB_LOOKUP_IGNORE_LINKSTATE |
785 FIB_LOOKUP_NOREF);
786
787 /* on error or if no table given do full lookup. This
788 * is needed for example when nexthops are in the local
789 * table rather than the given table
790 */
791 if (!tbl || err) {
792 err = fib_lookup(net, &fl4, &res,
793 FIB_LOOKUP_IGNORE_LINKSTATE);
794 }
795
796 if (err) {
797 rcu_read_unlock();
798 return err;
799 }
800 }
801 err = -EINVAL;
802 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
803 goto out;
804 nh->nh_scope = res.scope;
805 nh->nh_oif = FIB_RES_OIF(res);
806 nh->nh_dev = dev = FIB_RES_DEV(res);
807 if (!dev)
808 goto out;
809 dev_hold(dev);
810 if (!netif_carrier_ok(dev))
811 nh->nh_flags |= RTNH_F_LINKDOWN;
812 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
813 } else {
814 struct in_device *in_dev;
815
816 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
817 return -EINVAL;
818
819 rcu_read_lock();
820 err = -ENODEV;
821 in_dev = inetdev_by_index(net, nh->nh_oif);
822 if (!in_dev)
823 goto out;
824 err = -ENETDOWN;
825 if (!(in_dev->dev->flags & IFF_UP))
826 goto out;
827 nh->nh_dev = in_dev->dev;
828 dev_hold(nh->nh_dev);
829 nh->nh_scope = RT_SCOPE_HOST;
830 if (!netif_carrier_ok(nh->nh_dev))
831 nh->nh_flags |= RTNH_F_LINKDOWN;
832 err = 0;
833 }
834 out:
835 rcu_read_unlock();
836 return err;
837 }
838
839 static inline unsigned int fib_laddr_hashfn(__be32 val)
840 {
841 unsigned int mask = (fib_info_hash_size - 1);
842
843 return ((__force u32)val ^
844 ((__force u32)val >> 7) ^
845 ((__force u32)val >> 14)) & mask;
846 }
847
848 static struct hlist_head *fib_info_hash_alloc(int bytes)
849 {
850 if (bytes <= PAGE_SIZE)
851 return kzalloc(bytes, GFP_KERNEL);
852 else
853 return (struct hlist_head *)
854 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
855 get_order(bytes));
856 }
857
858 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
859 {
860 if (!hash)
861 return;
862
863 if (bytes <= PAGE_SIZE)
864 kfree(hash);
865 else
866 free_pages((unsigned long) hash, get_order(bytes));
867 }
868
869 static void fib_info_hash_move(struct hlist_head *new_info_hash,
870 struct hlist_head *new_laddrhash,
871 unsigned int new_size)
872 {
873 struct hlist_head *old_info_hash, *old_laddrhash;
874 unsigned int old_size = fib_info_hash_size;
875 unsigned int i, bytes;
876
877 spin_lock_bh(&fib_info_lock);
878 old_info_hash = fib_info_hash;
879 old_laddrhash = fib_info_laddrhash;
880 fib_info_hash_size = new_size;
881
882 for (i = 0; i < old_size; i++) {
883 struct hlist_head *head = &fib_info_hash[i];
884 struct hlist_node *n;
885 struct fib_info *fi;
886
887 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
888 struct hlist_head *dest;
889 unsigned int new_hash;
890
891 new_hash = fib_info_hashfn(fi);
892 dest = &new_info_hash[new_hash];
893 hlist_add_head(&fi->fib_hash, dest);
894 }
895 }
896 fib_info_hash = new_info_hash;
897
898 for (i = 0; i < old_size; i++) {
899 struct hlist_head *lhead = &fib_info_laddrhash[i];
900 struct hlist_node *n;
901 struct fib_info *fi;
902
903 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
904 struct hlist_head *ldest;
905 unsigned int new_hash;
906
907 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
908 ldest = &new_laddrhash[new_hash];
909 hlist_add_head(&fi->fib_lhash, ldest);
910 }
911 }
912 fib_info_laddrhash = new_laddrhash;
913
914 spin_unlock_bh(&fib_info_lock);
915
916 bytes = old_size * sizeof(struct hlist_head *);
917 fib_info_hash_free(old_info_hash, bytes);
918 fib_info_hash_free(old_laddrhash, bytes);
919 }
920
921 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
922 {
923 nh->nh_saddr = inet_select_addr(nh->nh_dev,
924 nh->nh_gw,
925 nh->nh_parent->fib_scope);
926 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
927
928 return nh->nh_saddr;
929 }
930
931 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
932 {
933 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
934 fib_prefsrc != cfg->fc_dst) {
935 u32 tb_id = cfg->fc_table;
936 int rc;
937
938 if (tb_id == RT_TABLE_MAIN)
939 tb_id = RT_TABLE_LOCAL;
940
941 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
942 fib_prefsrc, tb_id);
943
944 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
945 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
946 fib_prefsrc, RT_TABLE_LOCAL);
947 }
948
949 if (rc != RTN_LOCAL)
950 return false;
951 }
952 return true;
953 }
954
955 static int
956 fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
957 {
958 bool ecn_ca = false;
959 struct nlattr *nla;
960 int remaining;
961
962 if (!cfg->fc_mx)
963 return 0;
964
965 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
966 int type = nla_type(nla);
967 u32 val;
968
969 if (!type)
970 continue;
971 if (type > RTAX_MAX)
972 return -EINVAL;
973
974 if (type == RTAX_CC_ALGO) {
975 char tmp[TCP_CA_NAME_MAX];
976
977 nla_strlcpy(tmp, nla, sizeof(tmp));
978 val = tcp_ca_get_key_by_name(tmp, &ecn_ca);
979 if (val == TCP_CA_UNSPEC)
980 return -EINVAL;
981 } else {
982 if (nla_len(nla) != sizeof(u32))
983 return -EINVAL;
984 val = nla_get_u32(nla);
985 }
986 if (type == RTAX_ADVMSS && val > 65535 - 40)
987 val = 65535 - 40;
988 if (type == RTAX_MTU && val > 65535 - 15)
989 val = 65535 - 15;
990 if (type == RTAX_HOPLIMIT && val > 255)
991 val = 255;
992 if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
993 return -EINVAL;
994 fi->fib_metrics->metrics[type - 1] = val;
995 }
996
997 if (ecn_ca)
998 fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
999
1000 return 0;
1001 }
1002
1003 struct fib_info *fib_create_info(struct fib_config *cfg)
1004 {
1005 int err;
1006 struct fib_info *fi = NULL;
1007 struct fib_info *ofi;
1008 int nhs = 1;
1009 struct net *net = cfg->fc_nlinfo.nl_net;
1010
1011 if (cfg->fc_type > RTN_MAX)
1012 goto err_inval;
1013
1014 /* Fast check to catch the most weird cases */
1015 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
1016 goto err_inval;
1017
1018 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
1019 goto err_inval;
1020
1021 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1022 if (cfg->fc_mp) {
1023 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
1024 if (nhs == 0)
1025 goto err_inval;
1026 }
1027 #endif
1028
1029 err = -ENOBUFS;
1030 if (fib_info_cnt >= fib_info_hash_size) {
1031 unsigned int new_size = fib_info_hash_size << 1;
1032 struct hlist_head *new_info_hash;
1033 struct hlist_head *new_laddrhash;
1034 unsigned int bytes;
1035
1036 if (!new_size)
1037 new_size = 16;
1038 bytes = new_size * sizeof(struct hlist_head *);
1039 new_info_hash = fib_info_hash_alloc(bytes);
1040 new_laddrhash = fib_info_hash_alloc(bytes);
1041 if (!new_info_hash || !new_laddrhash) {
1042 fib_info_hash_free(new_info_hash, bytes);
1043 fib_info_hash_free(new_laddrhash, bytes);
1044 } else
1045 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1046
1047 if (!fib_info_hash_size)
1048 goto failure;
1049 }
1050
1051 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
1052 if (!fi)
1053 goto failure;
1054 if (cfg->fc_mx) {
1055 fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
1056 if (unlikely(!fi->fib_metrics)) {
1057 kfree(fi);
1058 return ERR_PTR(err);
1059 }
1060 atomic_set(&fi->fib_metrics->refcnt, 1);
1061 } else {
1062 fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
1063 }
1064 fib_info_cnt++;
1065 fi->fib_net = net;
1066 fi->fib_protocol = cfg->fc_protocol;
1067 fi->fib_scope = cfg->fc_scope;
1068 fi->fib_flags = cfg->fc_flags;
1069 fi->fib_priority = cfg->fc_priority;
1070 fi->fib_prefsrc = cfg->fc_prefsrc;
1071 fi->fib_type = cfg->fc_type;
1072
1073 fi->fib_nhs = nhs;
1074 change_nexthops(fi) {
1075 nexthop_nh->nh_parent = fi;
1076 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
1077 if (!nexthop_nh->nh_pcpu_rth_output)
1078 goto failure;
1079 } endfor_nexthops(fi)
1080
1081 err = fib_convert_metrics(fi, cfg);
1082 if (err)
1083 goto failure;
1084
1085 if (cfg->fc_mp) {
1086 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1087 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
1088 if (err != 0)
1089 goto failure;
1090 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
1091 goto err_inval;
1092 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
1093 goto err_inval;
1094 #ifdef CONFIG_IP_ROUTE_CLASSID
1095 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
1096 goto err_inval;
1097 #endif
1098 #else
1099 goto err_inval;
1100 #endif
1101 } else {
1102 struct fib_nh *nh = fi->fib_nh;
1103
1104 if (cfg->fc_encap) {
1105 struct lwtunnel_state *lwtstate;
1106 struct net_device *dev = NULL;
1107
1108 if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE)
1109 goto err_inval;
1110 if (cfg->fc_oif)
1111 dev = __dev_get_by_index(net, cfg->fc_oif);
1112 err = lwtunnel_build_state(dev, cfg->fc_encap_type,
1113 cfg->fc_encap, AF_INET, cfg,
1114 &lwtstate);
1115 if (err)
1116 goto failure;
1117
1118 nh->nh_lwtstate = lwtstate_get(lwtstate);
1119 }
1120 nh->nh_oif = cfg->fc_oif;
1121 nh->nh_gw = cfg->fc_gw;
1122 nh->nh_flags = cfg->fc_flags;
1123 #ifdef CONFIG_IP_ROUTE_CLASSID
1124 nh->nh_tclassid = cfg->fc_flow;
1125 if (nh->nh_tclassid)
1126 fi->fib_net->ipv4.fib_num_tclassid_users++;
1127 #endif
1128 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1129 nh->nh_weight = 1;
1130 #endif
1131 }
1132
1133 if (fib_props[cfg->fc_type].error) {
1134 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
1135 goto err_inval;
1136 goto link_it;
1137 } else {
1138 switch (cfg->fc_type) {
1139 case RTN_UNICAST:
1140 case RTN_LOCAL:
1141 case RTN_BROADCAST:
1142 case RTN_ANYCAST:
1143 case RTN_MULTICAST:
1144 break;
1145 default:
1146 goto err_inval;
1147 }
1148 }
1149
1150 if (cfg->fc_scope > RT_SCOPE_HOST)
1151 goto err_inval;
1152
1153 if (cfg->fc_scope == RT_SCOPE_HOST) {
1154 struct fib_nh *nh = fi->fib_nh;
1155
1156 /* Local address is added. */
1157 if (nhs != 1 || nh->nh_gw)
1158 goto err_inval;
1159 nh->nh_scope = RT_SCOPE_NOWHERE;
1160 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
1161 err = -ENODEV;
1162 if (!nh->nh_dev)
1163 goto failure;
1164 } else {
1165 int linkdown = 0;
1166
1167 change_nexthops(fi) {
1168 err = fib_check_nh(cfg, fi, nexthop_nh);
1169 if (err != 0)
1170 goto failure;
1171 if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
1172 linkdown++;
1173 } endfor_nexthops(fi)
1174 if (linkdown == fi->fib_nhs)
1175 fi->fib_flags |= RTNH_F_LINKDOWN;
1176 }
1177
1178 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc))
1179 goto err_inval;
1180
1181 change_nexthops(fi) {
1182 fib_info_update_nh_saddr(net, nexthop_nh);
1183 fib_add_weight(fi, nexthop_nh);
1184 } endfor_nexthops(fi)
1185
1186 fib_rebalance(fi);
1187
1188 link_it:
1189 ofi = fib_find_info(fi);
1190 if (ofi) {
1191 fi->fib_dead = 1;
1192 free_fib_info(fi);
1193 ofi->fib_treeref++;
1194 return ofi;
1195 }
1196
1197 fi->fib_treeref++;
1198 atomic_inc(&fi->fib_clntref);
1199 spin_lock_bh(&fib_info_lock);
1200 hlist_add_head(&fi->fib_hash,
1201 &fib_info_hash[fib_info_hashfn(fi)]);
1202 if (fi->fib_prefsrc) {
1203 struct hlist_head *head;
1204
1205 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1206 hlist_add_head(&fi->fib_lhash, head);
1207 }
1208 change_nexthops(fi) {
1209 struct hlist_head *head;
1210 unsigned int hash;
1211
1212 if (!nexthop_nh->nh_dev)
1213 continue;
1214 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
1215 head = &fib_info_devhash[hash];
1216 hlist_add_head(&nexthop_nh->nh_hash, head);
1217 } endfor_nexthops(fi)
1218 spin_unlock_bh(&fib_info_lock);
1219 return fi;
1220
1221 err_inval:
1222 err = -EINVAL;
1223
1224 failure:
1225 if (fi) {
1226 fi->fib_dead = 1;
1227 free_fib_info(fi);
1228 }
1229
1230 return ERR_PTR(err);
1231 }
1232
1233 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1234 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
1235 struct fib_info *fi, unsigned int flags)
1236 {
1237 struct nlmsghdr *nlh;
1238 struct rtmsg *rtm;
1239
1240 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1241 if (!nlh)
1242 return -EMSGSIZE;
1243
1244 rtm = nlmsg_data(nlh);
1245 rtm->rtm_family = AF_INET;
1246 rtm->rtm_dst_len = dst_len;
1247 rtm->rtm_src_len = 0;
1248 rtm->rtm_tos = tos;
1249 if (tb_id < 256)
1250 rtm->rtm_table = tb_id;
1251 else
1252 rtm->rtm_table = RT_TABLE_COMPAT;
1253 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1254 goto nla_put_failure;
1255 rtm->rtm_type = type;
1256 rtm->rtm_flags = fi->fib_flags;
1257 rtm->rtm_scope = fi->fib_scope;
1258 rtm->rtm_protocol = fi->fib_protocol;
1259
1260 if (rtm->rtm_dst_len &&
1261 nla_put_in_addr(skb, RTA_DST, dst))
1262 goto nla_put_failure;
1263 if (fi->fib_priority &&
1264 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1265 goto nla_put_failure;
1266 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1267 goto nla_put_failure;
1268
1269 if (fi->fib_prefsrc &&
1270 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1271 goto nla_put_failure;
1272 if (fi->fib_nhs == 1) {
1273 struct in_device *in_dev;
1274
1275 if (fi->fib_nh->nh_gw &&
1276 nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1277 goto nla_put_failure;
1278 if (fi->fib_nh->nh_oif &&
1279 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1280 goto nla_put_failure;
1281 if (fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) {
1282 in_dev = __in_dev_get_rtnl(fi->fib_nh->nh_dev);
1283 if (in_dev &&
1284 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1285 rtm->rtm_flags |= RTNH_F_DEAD;
1286 }
1287 #ifdef CONFIG_IP_ROUTE_CLASSID
1288 if (fi->fib_nh[0].nh_tclassid &&
1289 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1290 goto nla_put_failure;
1291 #endif
1292 if (fi->fib_nh->nh_lwtstate &&
1293 lwtunnel_fill_encap(skb, fi->fib_nh->nh_lwtstate) < 0)
1294 goto nla_put_failure;
1295 }
1296 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1297 if (fi->fib_nhs > 1) {
1298 struct rtnexthop *rtnh;
1299 struct nlattr *mp;
1300
1301 mp = nla_nest_start(skb, RTA_MULTIPATH);
1302 if (!mp)
1303 goto nla_put_failure;
1304
1305 for_nexthops(fi) {
1306 struct in_device *in_dev;
1307
1308 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1309 if (!rtnh)
1310 goto nla_put_failure;
1311
1312 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1313 if (nh->nh_flags & RTNH_F_LINKDOWN) {
1314 in_dev = __in_dev_get_rtnl(nh->nh_dev);
1315 if (in_dev &&
1316 IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev))
1317 rtnh->rtnh_flags |= RTNH_F_DEAD;
1318 }
1319 rtnh->rtnh_hops = nh->nh_weight - 1;
1320 rtnh->rtnh_ifindex = nh->nh_oif;
1321
1322 if (nh->nh_gw &&
1323 nla_put_in_addr(skb, RTA_GATEWAY, nh->nh_gw))
1324 goto nla_put_failure;
1325 #ifdef CONFIG_IP_ROUTE_CLASSID
1326 if (nh->nh_tclassid &&
1327 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1328 goto nla_put_failure;
1329 #endif
1330 if (nh->nh_lwtstate &&
1331 lwtunnel_fill_encap(skb, nh->nh_lwtstate) < 0)
1332 goto nla_put_failure;
1333
1334 /* length of rtnetlink header + attributes */
1335 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1336 } endfor_nexthops(fi);
1337
1338 nla_nest_end(skb, mp);
1339 }
1340 #endif
1341 nlmsg_end(skb, nlh);
1342 return 0;
1343
1344 nla_put_failure:
1345 nlmsg_cancel(skb, nlh);
1346 return -EMSGSIZE;
1347 }
1348
1349 /*
1350 * Update FIB if:
1351 * - local address disappeared -> we must delete all the entries
1352 * referring to it.
1353 * - device went down -> we must shutdown all nexthops going via it.
1354 */
1355 int fib_sync_down_addr(struct net *net, __be32 local)
1356 {
1357 int ret = 0;
1358 unsigned int hash = fib_laddr_hashfn(local);
1359 struct hlist_head *head = &fib_info_laddrhash[hash];
1360 struct fib_info *fi;
1361
1362 if (!fib_info_laddrhash || local == 0)
1363 return 0;
1364
1365 hlist_for_each_entry(fi, head, fib_lhash) {
1366 if (!net_eq(fi->fib_net, net))
1367 continue;
1368 if (fi->fib_prefsrc == local) {
1369 fi->fib_flags |= RTNH_F_DEAD;
1370 ret++;
1371 }
1372 }
1373 return ret;
1374 }
1375
1376 /* Update the PMTU of exceptions when:
1377 * - the new MTU of the first hop becomes smaller than the PMTU
1378 * - the old MTU was the same as the PMTU, and it limited discovery of
1379 * larger MTUs on the path. With that limit raised, we can now
1380 * discover larger MTUs
1381 * A special case is locked exceptions, for which the PMTU is smaller
1382 * than the minimal accepted PMTU:
1383 * - if the new MTU is greater than the PMTU, don't make any change
1384 * - otherwise, unlock and set PMTU
1385 */
1386 static void nh_update_mtu(struct fib_nh *nh, u32 new, u32 orig)
1387 {
1388 struct fnhe_hash_bucket *bucket;
1389 int i;
1390
1391 bucket = rcu_dereference_protected(nh->nh_exceptions, 1);
1392 if (!bucket)
1393 return;
1394
1395 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1396 struct fib_nh_exception *fnhe;
1397
1398 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1399 fnhe;
1400 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1401 if (fnhe->fnhe_mtu_locked) {
1402 if (new <= fnhe->fnhe_pmtu) {
1403 fnhe->fnhe_pmtu = new;
1404 fnhe->fnhe_mtu_locked = false;
1405 }
1406 } else if (new < fnhe->fnhe_pmtu ||
1407 orig == fnhe->fnhe_pmtu) {
1408 fnhe->fnhe_pmtu = new;
1409 }
1410 }
1411 }
1412 }
1413
1414 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1415 {
1416 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1417 struct hlist_head *head = &fib_info_devhash[hash];
1418 struct fib_nh *nh;
1419
1420 hlist_for_each_entry(nh, head, nh_hash) {
1421 if (nh->nh_dev == dev)
1422 nh_update_mtu(nh, dev->mtu, orig_mtu);
1423 }
1424 }
1425
1426 /* Event force Flags Description
1427 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1428 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1429 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1430 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1431 */
1432 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1433 {
1434 int ret = 0;
1435 int scope = RT_SCOPE_NOWHERE;
1436 struct fib_info *prev_fi = NULL;
1437 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1438 struct hlist_head *head = &fib_info_devhash[hash];
1439 struct fib_nh *nh;
1440
1441 if (force)
1442 scope = -1;
1443
1444 hlist_for_each_entry(nh, head, nh_hash) {
1445 struct fib_info *fi = nh->nh_parent;
1446 int dead;
1447
1448 BUG_ON(!fi->fib_nhs);
1449 if (nh->nh_dev != dev || fi == prev_fi)
1450 continue;
1451 prev_fi = fi;
1452 dead = 0;
1453 change_nexthops(fi) {
1454 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1455 dead++;
1456 else if (nexthop_nh->nh_dev == dev &&
1457 nexthop_nh->nh_scope != scope) {
1458 switch (event) {
1459 case NETDEV_DOWN:
1460 case NETDEV_UNREGISTER:
1461 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1462 /* fall through */
1463 case NETDEV_CHANGE:
1464 nexthop_nh->nh_flags |= RTNH_F_LINKDOWN;
1465 break;
1466 }
1467 dead++;
1468 }
1469 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1470 if (event == NETDEV_UNREGISTER &&
1471 nexthop_nh->nh_dev == dev) {
1472 dead = fi->fib_nhs;
1473 break;
1474 }
1475 #endif
1476 } endfor_nexthops(fi)
1477 if (dead == fi->fib_nhs) {
1478 switch (event) {
1479 case NETDEV_DOWN:
1480 case NETDEV_UNREGISTER:
1481 fi->fib_flags |= RTNH_F_DEAD;
1482 /* fall through */
1483 case NETDEV_CHANGE:
1484 fi->fib_flags |= RTNH_F_LINKDOWN;
1485 break;
1486 }
1487 ret++;
1488 }
1489
1490 fib_rebalance(fi);
1491 }
1492
1493 return ret;
1494 }
1495
1496 /* Must be invoked inside of an RCU protected region. */
1497 void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
1498 {
1499 struct fib_info *fi = NULL, *last_resort = NULL;
1500 struct hlist_head *fa_head = res->fa_head;
1501 struct fib_table *tb = res->table;
1502 u8 slen = 32 - res->prefixlen;
1503 int order = -1, last_idx = -1;
1504 struct fib_alias *fa, *fa1 = NULL;
1505 u32 last_prio = res->fi->fib_priority;
1506 u8 last_tos = 0;
1507
1508 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
1509 struct fib_info *next_fi = fa->fa_info;
1510
1511 if (fa->fa_slen != slen)
1512 continue;
1513 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
1514 continue;
1515 if (fa->tb_id != tb->tb_id)
1516 continue;
1517 if (next_fi->fib_priority > last_prio &&
1518 fa->fa_tos == last_tos) {
1519 if (last_tos)
1520 continue;
1521 break;
1522 }
1523 if (next_fi->fib_flags & RTNH_F_DEAD)
1524 continue;
1525 last_tos = fa->fa_tos;
1526 last_prio = next_fi->fib_priority;
1527
1528 if (next_fi->fib_scope != res->scope ||
1529 fa->fa_type != RTN_UNICAST)
1530 continue;
1531 if (!next_fi->fib_nh[0].nh_gw ||
1532 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1533 continue;
1534
1535 fib_alias_accessed(fa);
1536
1537 if (!fi) {
1538 if (next_fi != res->fi)
1539 break;
1540 fa1 = fa;
1541 } else if (!fib_detect_death(fi, order, &last_resort,
1542 &last_idx, fa1->fa_default)) {
1543 fib_result_assign(res, fi);
1544 fa1->fa_default = order;
1545 goto out;
1546 }
1547 fi = next_fi;
1548 order++;
1549 }
1550
1551 if (order <= 0 || !fi) {
1552 if (fa1)
1553 fa1->fa_default = -1;
1554 goto out;
1555 }
1556
1557 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1558 fa1->fa_default)) {
1559 fib_result_assign(res, fi);
1560 fa1->fa_default = order;
1561 goto out;
1562 }
1563
1564 if (last_idx >= 0)
1565 fib_result_assign(res, last_resort);
1566 fa1->fa_default = last_idx;
1567 out:
1568 return;
1569 }
1570
1571 /*
1572 * Dead device goes up. We wake up dead nexthops.
1573 * It takes sense only on multipath routes.
1574 */
1575 int fib_sync_up(struct net_device *dev, unsigned int nh_flags)
1576 {
1577 struct fib_info *prev_fi;
1578 unsigned int hash;
1579 struct hlist_head *head;
1580 struct fib_nh *nh;
1581 int ret;
1582
1583 if (!(dev->flags & IFF_UP))
1584 return 0;
1585
1586 if (nh_flags & RTNH_F_DEAD) {
1587 unsigned int flags = dev_get_flags(dev);
1588
1589 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
1590 nh_flags |= RTNH_F_LINKDOWN;
1591 }
1592
1593 prev_fi = NULL;
1594 hash = fib_devindex_hashfn(dev->ifindex);
1595 head = &fib_info_devhash[hash];
1596 ret = 0;
1597
1598 hlist_for_each_entry(nh, head, nh_hash) {
1599 struct fib_info *fi = nh->nh_parent;
1600 int alive;
1601
1602 BUG_ON(!fi->fib_nhs);
1603 if (nh->nh_dev != dev || fi == prev_fi)
1604 continue;
1605
1606 prev_fi = fi;
1607 alive = 0;
1608 change_nexthops(fi) {
1609 if (!(nexthop_nh->nh_flags & nh_flags)) {
1610 alive++;
1611 continue;
1612 }
1613 if (!nexthop_nh->nh_dev ||
1614 !(nexthop_nh->nh_dev->flags & IFF_UP))
1615 continue;
1616 if (nexthop_nh->nh_dev != dev ||
1617 !__in_dev_get_rtnl(dev))
1618 continue;
1619 alive++;
1620 nexthop_nh->nh_flags &= ~nh_flags;
1621 } endfor_nexthops(fi)
1622
1623 if (alive > 0) {
1624 fi->fib_flags &= ~nh_flags;
1625 ret++;
1626 }
1627
1628 fib_rebalance(fi);
1629 }
1630
1631 return ret;
1632 }
1633
1634 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1635
1636 void fib_select_multipath(struct fib_result *res, int hash)
1637 {
1638 struct fib_info *fi = res->fi;
1639
1640 for_nexthops(fi) {
1641 if (hash > atomic_read(&nh->nh_upper_bound))
1642 continue;
1643
1644 res->nh_sel = nhsel;
1645 return;
1646 } endfor_nexthops(fi);
1647
1648 /* Race condition: route has just become dead. */
1649 res->nh_sel = 0;
1650 }
1651 #endif
1652
1653 void fib_select_path(struct net *net, struct fib_result *res,
1654 struct flowi4 *fl4, int mp_hash)
1655 {
1656 bool oif_check;
1657
1658 oif_check = (fl4->flowi4_oif == 0 ||
1659 fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF);
1660
1661 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1662 if (res->fi->fib_nhs > 1 && oif_check) {
1663 if (mp_hash < 0)
1664 mp_hash = get_hash_from_flowi4(fl4) >> 1;
1665
1666 fib_select_multipath(res, mp_hash);
1667 }
1668 else
1669 #endif
1670 if (!res->prefixlen &&
1671 res->table->tb_num_default > 1 &&
1672 res->type == RTN_UNICAST && oif_check)
1673 fib_select_default(fl4, res);
1674
1675 if (!fl4->saddr)
1676 fl4->saddr = FIB_RES_PREFSRC(net, *res);
1677 }
1678 EXPORT_SYMBOL_GPL(fib_select_path);
Linux with added FPC-III support