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MAINTAINERS: EDAC: add Mauro and Borislav as interim patch collectors
[linux-2.6/btrfs-unstable.git] / net / ipv4 / fib_semantics.c
blobb53f0bf84dcaba3fd2767dd734add99d05db9fa6
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
46 #include "fib_lookup.h"
47
48 static DEFINE_SPINLOCK(fib_info_lock);
49 static struct hlist_head *fib_info_hash;
50 static struct hlist_head *fib_info_laddrhash;
51 static unsigned int fib_info_hash_size;
52 static unsigned int fib_info_cnt;
53
54 #define DEVINDEX_HASHBITS 8
55 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
56 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
57
58 #ifdef CONFIG_IP_ROUTE_MULTIPATH
59
60 static DEFINE_SPINLOCK(fib_multipath_lock);
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 = nh->nh_exceptions;
161 int i;
162
163 for (i = 0; i < FNHE_HASH_SIZE; i++) {
164 struct fib_nh_exception *fnhe;
165
166 fnhe = rcu_dereference_protected(hash[i].chain, 1);
167 while (fnhe) {
168 struct fib_nh_exception *next;
169
170 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
171
172 rt_fibinfo_free(&fnhe->fnhe_rth_input);
173 rt_fibinfo_free(&fnhe->fnhe_rth_output);
174
175 kfree(fnhe);
176
177 fnhe = next;
178 }
179 }
180 kfree(hash);
181 }
182
183 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
184 {
185 int cpu;
186
187 if (!rtp)
188 return;
189
190 for_each_possible_cpu(cpu) {
191 struct rtable *rt;
192
193 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
194 if (rt)
195 dst_free(&rt->dst);
196 }
197 free_percpu(rtp);
198 }
199
200 /* Release a nexthop info record */
201 static void free_fib_info_rcu(struct rcu_head *head)
202 {
203 struct fib_info *fi = container_of(head, struct fib_info, rcu);
204
205 change_nexthops(fi) {
206 if (nexthop_nh->nh_dev)
207 dev_put(nexthop_nh->nh_dev);
208 if (nexthop_nh->nh_exceptions)
209 free_nh_exceptions(nexthop_nh);
210 rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
211 rt_fibinfo_free(&nexthop_nh->nh_rth_input);
212 } endfor_nexthops(fi);
213
214 release_net(fi->fib_net);
215 if (fi->fib_metrics != (u32 *) dst_default_metrics)
216 kfree(fi->fib_metrics);
217 kfree(fi);
218 }
219
220 void free_fib_info(struct fib_info *fi)
221 {
222 if (fi->fib_dead == 0) {
223 pr_warn("Freeing alive fib_info %p\n", fi);
224 return;
225 }
226 fib_info_cnt--;
227 #ifdef CONFIG_IP_ROUTE_CLASSID
228 change_nexthops(fi) {
229 if (nexthop_nh->nh_tclassid)
230 fi->fib_net->ipv4.fib_num_tclassid_users--;
231 } endfor_nexthops(fi);
232 #endif
233 call_rcu(&fi->rcu, free_fib_info_rcu);
234 }
235
236 void fib_release_info(struct fib_info *fi)
237 {
238 spin_lock_bh(&fib_info_lock);
239 if (fi && --fi->fib_treeref == 0) {
240 hlist_del(&fi->fib_hash);
241 if (fi->fib_prefsrc)
242 hlist_del(&fi->fib_lhash);
243 change_nexthops(fi) {
244 if (!nexthop_nh->nh_dev)
245 continue;
246 hlist_del(&nexthop_nh->nh_hash);
247 } endfor_nexthops(fi)
248 fi->fib_dead = 1;
249 fib_info_put(fi);
250 }
251 spin_unlock_bh(&fib_info_lock);
252 }
253
254 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
255 {
256 const struct fib_nh *onh = ofi->fib_nh;
257
258 for_nexthops(fi) {
259 if (nh->nh_oif != onh->nh_oif ||
260 nh->nh_gw != onh->nh_gw ||
261 nh->nh_scope != onh->nh_scope ||
262 #ifdef CONFIG_IP_ROUTE_MULTIPATH
263 nh->nh_weight != onh->nh_weight ||
264 #endif
265 #ifdef CONFIG_IP_ROUTE_CLASSID
266 nh->nh_tclassid != onh->nh_tclassid ||
267 #endif
268 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
269 return -1;
270 onh++;
271 } endfor_nexthops(fi);
272 return 0;
273 }
274
275 static inline unsigned int fib_devindex_hashfn(unsigned int val)
276 {
277 unsigned int mask = DEVINDEX_HASHSIZE - 1;
278
279 return (val ^
280 (val >> DEVINDEX_HASHBITS) ^
281 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
282 }
283
284 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
285 {
286 unsigned int mask = (fib_info_hash_size - 1);
287 unsigned int val = fi->fib_nhs;
288
289 val ^= (fi->fib_protocol << 8) | fi->fib_scope;
290 val ^= (__force u32)fi->fib_prefsrc;
291 val ^= fi->fib_priority;
292 for_nexthops(fi) {
293 val ^= fib_devindex_hashfn(nh->nh_oif);
294 } endfor_nexthops(fi)
295
296 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
297 }
298
299 static struct fib_info *fib_find_info(const struct fib_info *nfi)
300 {
301 struct hlist_head *head;
302 struct fib_info *fi;
303 unsigned int hash;
304
305 hash = fib_info_hashfn(nfi);
306 head = &fib_info_hash[hash];
307
308 hlist_for_each_entry(fi, head, fib_hash) {
309 if (!net_eq(fi->fib_net, nfi->fib_net))
310 continue;
311 if (fi->fib_nhs != nfi->fib_nhs)
312 continue;
313 if (nfi->fib_protocol == fi->fib_protocol &&
314 nfi->fib_scope == fi->fib_scope &&
315 nfi->fib_prefsrc == fi->fib_prefsrc &&
316 nfi->fib_priority == fi->fib_priority &&
317 nfi->fib_type == fi->fib_type &&
318 memcmp(nfi->fib_metrics, fi->fib_metrics,
319 sizeof(u32) * RTAX_MAX) == 0 &&
320 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
321 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
322 return fi;
323 }
324
325 return NULL;
326 }
327
328 /* Check, that the gateway is already configured.
329 * Used only by redirect accept routine.
330 */
331 int ip_fib_check_default(__be32 gw, struct net_device *dev)
332 {
333 struct hlist_head *head;
334 struct fib_nh *nh;
335 unsigned int hash;
336
337 spin_lock(&fib_info_lock);
338
339 hash = fib_devindex_hashfn(dev->ifindex);
340 head = &fib_info_devhash[hash];
341 hlist_for_each_entry(nh, head, nh_hash) {
342 if (nh->nh_dev == dev &&
343 nh->nh_gw == gw &&
344 !(nh->nh_flags & RTNH_F_DEAD)) {
345 spin_unlock(&fib_info_lock);
346 return 0;
347 }
348 }
349
350 spin_unlock(&fib_info_lock);
351
352 return -1;
353 }
354
355 static inline size_t fib_nlmsg_size(struct fib_info *fi)
356 {
357 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
358 + nla_total_size(4) /* RTA_TABLE */
359 + nla_total_size(4) /* RTA_DST */
360 + nla_total_size(4) /* RTA_PRIORITY */
361 + nla_total_size(4); /* RTA_PREFSRC */
362
363 /* space for nested metrics */
364 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
365
366 if (fi->fib_nhs) {
367 /* Also handles the special case fib_nhs == 1 */
368
369 /* each nexthop is packed in an attribute */
370 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
371
372 /* may contain flow and gateway attribute */
373 nhsize += 2 * nla_total_size(4);
374
375 /* all nexthops are packed in a nested attribute */
376 payload += nla_total_size(fi->fib_nhs * nhsize);
377 }
378
379 return payload;
380 }
381
382 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
383 int dst_len, u32 tb_id, const struct nl_info *info,
384 unsigned int nlm_flags)
385 {
386 struct sk_buff *skb;
387 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
388 int err = -ENOBUFS;
389
390 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
391 if (skb == NULL)
392 goto errout;
393
394 err = fib_dump_info(skb, info->portid, seq, event, tb_id,
395 fa->fa_type, key, dst_len,
396 fa->fa_tos, fa->fa_info, nlm_flags);
397 if (err < 0) {
398 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
399 WARN_ON(err == -EMSGSIZE);
400 kfree_skb(skb);
401 goto errout;
402 }
403 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
404 info->nlh, GFP_KERNEL);
405 return;
406 errout:
407 if (err < 0)
408 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
409 }
410
411 /* Return the first fib alias matching TOS with
412 * priority less than or equal to PRIO.
413 */
414 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
415 {
416 if (fah) {
417 struct fib_alias *fa;
418 list_for_each_entry(fa, fah, fa_list) {
419 if (fa->fa_tos > tos)
420 continue;
421 if (fa->fa_info->fib_priority >= prio ||
422 fa->fa_tos < tos)
423 return fa;
424 }
425 }
426 return NULL;
427 }
428
429 static int fib_detect_death(struct fib_info *fi, int order,
430 struct fib_info **last_resort, int *last_idx,
431 int dflt)
432 {
433 struct neighbour *n;
434 int state = NUD_NONE;
435
436 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
437 if (n) {
438 state = n->nud_state;
439 neigh_release(n);
440 }
441 if (state == NUD_REACHABLE)
442 return 0;
443 if ((state & NUD_VALID) && order != dflt)
444 return 0;
445 if ((state & NUD_VALID) ||
446 (*last_idx < 0 && order > dflt)) {
447 *last_resort = fi;
448 *last_idx = order;
449 }
450 return 1;
451 }
452
453 #ifdef CONFIG_IP_ROUTE_MULTIPATH
454
455 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
456 {
457 int nhs = 0;
458
459 while (rtnh_ok(rtnh, remaining)) {
460 nhs++;
461 rtnh = rtnh_next(rtnh, &remaining);
462 }
463
464 /* leftover implies invalid nexthop configuration, discard it */
465 return remaining > 0 ? 0 : nhs;
466 }
467
468 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
469 int remaining, struct fib_config *cfg)
470 {
471 change_nexthops(fi) {
472 int attrlen;
473
474 if (!rtnh_ok(rtnh, remaining))
475 return -EINVAL;
476
477 nexthop_nh->nh_flags =
478 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
479 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
480 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
481
482 attrlen = rtnh_attrlen(rtnh);
483 if (attrlen > 0) {
484 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
485
486 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
487 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
488 #ifdef CONFIG_IP_ROUTE_CLASSID
489 nla = nla_find(attrs, attrlen, RTA_FLOW);
490 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
491 if (nexthop_nh->nh_tclassid)
492 fi->fib_net->ipv4.fib_num_tclassid_users++;
493 #endif
494 }
495
496 rtnh = rtnh_next(rtnh, &remaining);
497 } endfor_nexthops(fi);
498
499 return 0;
500 }
501
502 #endif
503
504 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
505 {
506 #ifdef CONFIG_IP_ROUTE_MULTIPATH
507 struct rtnexthop *rtnh;
508 int remaining;
509 #endif
510
511 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
512 return 1;
513
514 if (cfg->fc_oif || cfg->fc_gw) {
515 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
516 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
517 return 0;
518 return 1;
519 }
520
521 #ifdef CONFIG_IP_ROUTE_MULTIPATH
522 if (cfg->fc_mp == NULL)
523 return 0;
524
525 rtnh = cfg->fc_mp;
526 remaining = cfg->fc_mp_len;
527
528 for_nexthops(fi) {
529 int attrlen;
530
531 if (!rtnh_ok(rtnh, remaining))
532 return -EINVAL;
533
534 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
535 return 1;
536
537 attrlen = rtnh_attrlen(rtnh);
538 if (attrlen < 0) {
539 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
540
541 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
542 if (nla && nla_get_be32(nla) != nh->nh_gw)
543 return 1;
544 #ifdef CONFIG_IP_ROUTE_CLASSID
545 nla = nla_find(attrs, attrlen, RTA_FLOW);
546 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
547 return 1;
548 #endif
549 }
550
551 rtnh = rtnh_next(rtnh, &remaining);
552 } endfor_nexthops(fi);
553 #endif
554 return 0;
555 }
556
557
558 /*
559 * Picture
560 * -------
561 *
562 * Semantics of nexthop is very messy by historical reasons.
563 * We have to take into account, that:
564 * a) gateway can be actually local interface address,
565 * so that gatewayed route is direct.
566 * b) gateway must be on-link address, possibly
567 * described not by an ifaddr, but also by a direct route.
568 * c) If both gateway and interface are specified, they should not
569 * contradict.
570 * d) If we use tunnel routes, gateway could be not on-link.
571 *
572 * Attempt to reconcile all of these (alas, self-contradictory) conditions
573 * results in pretty ugly and hairy code with obscure logic.
574 *
575 * I chose to generalized it instead, so that the size
576 * of code does not increase practically, but it becomes
577 * much more general.
578 * Every prefix is assigned a "scope" value: "host" is local address,
579 * "link" is direct route,
580 * [ ... "site" ... "interior" ... ]
581 * and "universe" is true gateway route with global meaning.
582 *
583 * Every prefix refers to a set of "nexthop"s (gw, oif),
584 * where gw must have narrower scope. This recursion stops
585 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
586 * which means that gw is forced to be on link.
587 *
588 * Code is still hairy, but now it is apparently logically
589 * consistent and very flexible. F.e. as by-product it allows
590 * to co-exists in peace independent exterior and interior
591 * routing processes.
592 *
593 * Normally it looks as following.
594 *
595 * {universe prefix} -> (gw, oif) [scope link]
596 * |
597 * |-> {link prefix} -> (gw, oif) [scope local]
598 * |
599 * |-> {local prefix} (terminal node)
600 */
601 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
602 struct fib_nh *nh)
603 {
604 int err;
605 struct net *net;
606 struct net_device *dev;
607
608 net = cfg->fc_nlinfo.nl_net;
609 if (nh->nh_gw) {
610 struct fib_result res;
611
612 if (nh->nh_flags & RTNH_F_ONLINK) {
613
614 if (cfg->fc_scope >= RT_SCOPE_LINK)
615 return -EINVAL;
616 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
617 return -EINVAL;
618 dev = __dev_get_by_index(net, nh->nh_oif);
619 if (!dev)
620 return -ENODEV;
621 if (!(dev->flags & IFF_UP))
622 return -ENETDOWN;
623 nh->nh_dev = dev;
624 dev_hold(dev);
625 nh->nh_scope = RT_SCOPE_LINK;
626 return 0;
627 }
628 rcu_read_lock();
629 {
630 struct flowi4 fl4 = {
631 .daddr = nh->nh_gw,
632 .flowi4_scope = cfg->fc_scope + 1,
633 .flowi4_oif = nh->nh_oif,
634 };
635
636 /* It is not necessary, but requires a bit of thinking */
637 if (fl4.flowi4_scope < RT_SCOPE_LINK)
638 fl4.flowi4_scope = RT_SCOPE_LINK;
639 err = fib_lookup(net, &fl4, &res);
640 if (err) {
641 rcu_read_unlock();
642 return err;
643 }
644 }
645 err = -EINVAL;
646 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
647 goto out;
648 nh->nh_scope = res.scope;
649 nh->nh_oif = FIB_RES_OIF(res);
650 nh->nh_dev = dev = FIB_RES_DEV(res);
651 if (!dev)
652 goto out;
653 dev_hold(dev);
654 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
655 } else {
656 struct in_device *in_dev;
657
658 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
659 return -EINVAL;
660
661 rcu_read_lock();
662 err = -ENODEV;
663 in_dev = inetdev_by_index(net, nh->nh_oif);
664 if (in_dev == NULL)
665 goto out;
666 err = -ENETDOWN;
667 if (!(in_dev->dev->flags & IFF_UP))
668 goto out;
669 nh->nh_dev = in_dev->dev;
670 dev_hold(nh->nh_dev);
671 nh->nh_scope = RT_SCOPE_HOST;
672 err = 0;
673 }
674 out:
675 rcu_read_unlock();
676 return err;
677 }
678
679 static inline unsigned int fib_laddr_hashfn(__be32 val)
680 {
681 unsigned int mask = (fib_info_hash_size - 1);
682
683 return ((__force u32)val ^
684 ((__force u32)val >> 7) ^
685 ((__force u32)val >> 14)) & mask;
686 }
687
688 static struct hlist_head *fib_info_hash_alloc(int bytes)
689 {
690 if (bytes <= PAGE_SIZE)
691 return kzalloc(bytes, GFP_KERNEL);
692 else
693 return (struct hlist_head *)
694 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
695 get_order(bytes));
696 }
697
698 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
699 {
700 if (!hash)
701 return;
702
703 if (bytes <= PAGE_SIZE)
704 kfree(hash);
705 else
706 free_pages((unsigned long) hash, get_order(bytes));
707 }
708
709 static void fib_info_hash_move(struct hlist_head *new_info_hash,
710 struct hlist_head *new_laddrhash,
711 unsigned int new_size)
712 {
713 struct hlist_head *old_info_hash, *old_laddrhash;
714 unsigned int old_size = fib_info_hash_size;
715 unsigned int i, bytes;
716
717 spin_lock_bh(&fib_info_lock);
718 old_info_hash = fib_info_hash;
719 old_laddrhash = fib_info_laddrhash;
720 fib_info_hash_size = new_size;
721
722 for (i = 0; i < old_size; i++) {
723 struct hlist_head *head = &fib_info_hash[i];
724 struct hlist_node *n;
725 struct fib_info *fi;
726
727 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
728 struct hlist_head *dest;
729 unsigned int new_hash;
730
731 hlist_del(&fi->fib_hash);
732
733 new_hash = fib_info_hashfn(fi);
734 dest = &new_info_hash[new_hash];
735 hlist_add_head(&fi->fib_hash, dest);
736 }
737 }
738 fib_info_hash = new_info_hash;
739
740 for (i = 0; i < old_size; i++) {
741 struct hlist_head *lhead = &fib_info_laddrhash[i];
742 struct hlist_node *n;
743 struct fib_info *fi;
744
745 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
746 struct hlist_head *ldest;
747 unsigned int new_hash;
748
749 hlist_del(&fi->fib_lhash);
750
751 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
752 ldest = &new_laddrhash[new_hash];
753 hlist_add_head(&fi->fib_lhash, ldest);
754 }
755 }
756 fib_info_laddrhash = new_laddrhash;
757
758 spin_unlock_bh(&fib_info_lock);
759
760 bytes = old_size * sizeof(struct hlist_head *);
761 fib_info_hash_free(old_info_hash, bytes);
762 fib_info_hash_free(old_laddrhash, bytes);
763 }
764
765 __be32 fib_info_update_nh_saddr(struct net *net, struct fib_nh *nh)
766 {
767 nh->nh_saddr = inet_select_addr(nh->nh_dev,
768 nh->nh_gw,
769 nh->nh_parent->fib_scope);
770 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
771
772 return nh->nh_saddr;
773 }
774
775 struct fib_info *fib_create_info(struct fib_config *cfg)
776 {
777 int err;
778 struct fib_info *fi = NULL;
779 struct fib_info *ofi;
780 int nhs = 1;
781 struct net *net = cfg->fc_nlinfo.nl_net;
782
783 if (cfg->fc_type > RTN_MAX)
784 goto err_inval;
785
786 /* Fast check to catch the most weird cases */
787 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
788 goto err_inval;
789
790 #ifdef CONFIG_IP_ROUTE_MULTIPATH
791 if (cfg->fc_mp) {
792 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
793 if (nhs == 0)
794 goto err_inval;
795 }
796 #endif
797
798 err = -ENOBUFS;
799 if (fib_info_cnt >= fib_info_hash_size) {
800 unsigned int new_size = fib_info_hash_size << 1;
801 struct hlist_head *new_info_hash;
802 struct hlist_head *new_laddrhash;
803 unsigned int bytes;
804
805 if (!new_size)
806 new_size = 16;
807 bytes = new_size * sizeof(struct hlist_head *);
808 new_info_hash = fib_info_hash_alloc(bytes);
809 new_laddrhash = fib_info_hash_alloc(bytes);
810 if (!new_info_hash || !new_laddrhash) {
811 fib_info_hash_free(new_info_hash, bytes);
812 fib_info_hash_free(new_laddrhash, bytes);
813 } else
814 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
815
816 if (!fib_info_hash_size)
817 goto failure;
818 }
819
820 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
821 if (fi == NULL)
822 goto failure;
823 if (cfg->fc_mx) {
824 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
825 if (!fi->fib_metrics)
826 goto failure;
827 } else
828 fi->fib_metrics = (u32 *) dst_default_metrics;
829 fib_info_cnt++;
830
831 fi->fib_net = hold_net(net);
832 fi->fib_protocol = cfg->fc_protocol;
833 fi->fib_scope = cfg->fc_scope;
834 fi->fib_flags = cfg->fc_flags;
835 fi->fib_priority = cfg->fc_priority;
836 fi->fib_prefsrc = cfg->fc_prefsrc;
837 fi->fib_type = cfg->fc_type;
838
839 fi->fib_nhs = nhs;
840 change_nexthops(fi) {
841 nexthop_nh->nh_parent = fi;
842 nexthop_nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
843 if (!nexthop_nh->nh_pcpu_rth_output)
844 goto failure;
845 } endfor_nexthops(fi)
846
847 if (cfg->fc_mx) {
848 struct nlattr *nla;
849 int remaining;
850
851 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
852 int type = nla_type(nla);
853
854 if (type) {
855 u32 val;
856
857 if (type > RTAX_MAX)
858 goto err_inval;
859 val = nla_get_u32(nla);
860 if (type == RTAX_ADVMSS && val > 65535 - 40)
861 val = 65535 - 40;
862 if (type == RTAX_MTU && val > 65535 - 15)
863 val = 65535 - 15;
864 fi->fib_metrics[type - 1] = val;
865 }
866 }
867 }
868
869 if (cfg->fc_mp) {
870 #ifdef CONFIG_IP_ROUTE_MULTIPATH
871 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
872 if (err != 0)
873 goto failure;
874 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
875 goto err_inval;
876 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
877 goto err_inval;
878 #ifdef CONFIG_IP_ROUTE_CLASSID
879 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
880 goto err_inval;
881 #endif
882 #else
883 goto err_inval;
884 #endif
885 } else {
886 struct fib_nh *nh = fi->fib_nh;
887
888 nh->nh_oif = cfg->fc_oif;
889 nh->nh_gw = cfg->fc_gw;
890 nh->nh_flags = cfg->fc_flags;
891 #ifdef CONFIG_IP_ROUTE_CLASSID
892 nh->nh_tclassid = cfg->fc_flow;
893 if (nh->nh_tclassid)
894 fi->fib_net->ipv4.fib_num_tclassid_users++;
895 #endif
896 #ifdef CONFIG_IP_ROUTE_MULTIPATH
897 nh->nh_weight = 1;
898 #endif
899 }
900
901 if (fib_props[cfg->fc_type].error) {
902 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
903 goto err_inval;
904 goto link_it;
905 } else {
906 switch (cfg->fc_type) {
907 case RTN_UNICAST:
908 case RTN_LOCAL:
909 case RTN_BROADCAST:
910 case RTN_ANYCAST:
911 case RTN_MULTICAST:
912 break;
913 default:
914 goto err_inval;
915 }
916 }
917
918 if (cfg->fc_scope > RT_SCOPE_HOST)
919 goto err_inval;
920
921 if (cfg->fc_scope == RT_SCOPE_HOST) {
922 struct fib_nh *nh = fi->fib_nh;
923
924 /* Local address is added. */
925 if (nhs != 1 || nh->nh_gw)
926 goto err_inval;
927 nh->nh_scope = RT_SCOPE_NOWHERE;
928 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
929 err = -ENODEV;
930 if (nh->nh_dev == NULL)
931 goto failure;
932 } else {
933 change_nexthops(fi) {
934 err = fib_check_nh(cfg, fi, nexthop_nh);
935 if (err != 0)
936 goto failure;
937 } endfor_nexthops(fi)
938 }
939
940 if (fi->fib_prefsrc) {
941 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
942 fi->fib_prefsrc != cfg->fc_dst)
943 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
944 goto err_inval;
945 }
946
947 change_nexthops(fi) {
948 fib_info_update_nh_saddr(net, nexthop_nh);
949 } endfor_nexthops(fi)
950
951 link_it:
952 ofi = fib_find_info(fi);
953 if (ofi) {
954 fi->fib_dead = 1;
955 free_fib_info(fi);
956 ofi->fib_treeref++;
957 return ofi;
958 }
959
960 fi->fib_treeref++;
961 atomic_inc(&fi->fib_clntref);
962 spin_lock_bh(&fib_info_lock);
963 hlist_add_head(&fi->fib_hash,
964 &fib_info_hash[fib_info_hashfn(fi)]);
965 if (fi->fib_prefsrc) {
966 struct hlist_head *head;
967
968 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
969 hlist_add_head(&fi->fib_lhash, head);
970 }
971 change_nexthops(fi) {
972 struct hlist_head *head;
973 unsigned int hash;
974
975 if (!nexthop_nh->nh_dev)
976 continue;
977 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
978 head = &fib_info_devhash[hash];
979 hlist_add_head(&nexthop_nh->nh_hash, head);
980 } endfor_nexthops(fi)
981 spin_unlock_bh(&fib_info_lock);
982 return fi;
983
984 err_inval:
985 err = -EINVAL;
986
987 failure:
988 if (fi) {
989 fi->fib_dead = 1;
990 free_fib_info(fi);
991 }
992
993 return ERR_PTR(err);
994 }
995
996 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
997 u32 tb_id, u8 type, __be32 dst, int dst_len, u8 tos,
998 struct fib_info *fi, unsigned int flags)
999 {
1000 struct nlmsghdr *nlh;
1001 struct rtmsg *rtm;
1002
1003 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1004 if (nlh == NULL)
1005 return -EMSGSIZE;
1006
1007 rtm = nlmsg_data(nlh);
1008 rtm->rtm_family = AF_INET;
1009 rtm->rtm_dst_len = dst_len;
1010 rtm->rtm_src_len = 0;
1011 rtm->rtm_tos = tos;
1012 if (tb_id < 256)
1013 rtm->rtm_table = tb_id;
1014 else
1015 rtm->rtm_table = RT_TABLE_COMPAT;
1016 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1017 goto nla_put_failure;
1018 rtm->rtm_type = type;
1019 rtm->rtm_flags = fi->fib_flags;
1020 rtm->rtm_scope = fi->fib_scope;
1021 rtm->rtm_protocol = fi->fib_protocol;
1022
1023 if (rtm->rtm_dst_len &&
1024 nla_put_be32(skb, RTA_DST, dst))
1025 goto nla_put_failure;
1026 if (fi->fib_priority &&
1027 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1028 goto nla_put_failure;
1029 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
1030 goto nla_put_failure;
1031
1032 if (fi->fib_prefsrc &&
1033 nla_put_be32(skb, RTA_PREFSRC, fi->fib_prefsrc))
1034 goto nla_put_failure;
1035 if (fi->fib_nhs == 1) {
1036 if (fi->fib_nh->nh_gw &&
1037 nla_put_be32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw))
1038 goto nla_put_failure;
1039 if (fi->fib_nh->nh_oif &&
1040 nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif))
1041 goto nla_put_failure;
1042 #ifdef CONFIG_IP_ROUTE_CLASSID
1043 if (fi->fib_nh[0].nh_tclassid &&
1044 nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid))
1045 goto nla_put_failure;
1046 #endif
1047 }
1048 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1049 if (fi->fib_nhs > 1) {
1050 struct rtnexthop *rtnh;
1051 struct nlattr *mp;
1052
1053 mp = nla_nest_start(skb, RTA_MULTIPATH);
1054 if (mp == NULL)
1055 goto nla_put_failure;
1056
1057 for_nexthops(fi) {
1058 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1059 if (rtnh == NULL)
1060 goto nla_put_failure;
1061
1062 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1063 rtnh->rtnh_hops = nh->nh_weight - 1;
1064 rtnh->rtnh_ifindex = nh->nh_oif;
1065
1066 if (nh->nh_gw &&
1067 nla_put_be32(skb, RTA_GATEWAY, nh->nh_gw))
1068 goto nla_put_failure;
1069 #ifdef CONFIG_IP_ROUTE_CLASSID
1070 if (nh->nh_tclassid &&
1071 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1072 goto nla_put_failure;
1073 #endif
1074 /* length of rtnetlink header + attributes */
1075 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1076 } endfor_nexthops(fi);
1077
1078 nla_nest_end(skb, mp);
1079 }
1080 #endif
1081 return nlmsg_end(skb, nlh);
1082
1083 nla_put_failure:
1084 nlmsg_cancel(skb, nlh);
1085 return -EMSGSIZE;
1086 }
1087
1088 /*
1089 * Update FIB if:
1090 * - local address disappeared -> we must delete all the entries
1091 * referring to it.
1092 * - device went down -> we must shutdown all nexthops going via it.
1093 */
1094 int fib_sync_down_addr(struct net *net, __be32 local)
1095 {
1096 int ret = 0;
1097 unsigned int hash = fib_laddr_hashfn(local);
1098 struct hlist_head *head = &fib_info_laddrhash[hash];
1099 struct fib_info *fi;
1100
1101 if (fib_info_laddrhash == NULL || local == 0)
1102 return 0;
1103
1104 hlist_for_each_entry(fi, head, fib_lhash) {
1105 if (!net_eq(fi->fib_net, net))
1106 continue;
1107 if (fi->fib_prefsrc == local) {
1108 fi->fib_flags |= RTNH_F_DEAD;
1109 ret++;
1110 }
1111 }
1112 return ret;
1113 }
1114
1115 int fib_sync_down_dev(struct net_device *dev, int force)
1116 {
1117 int ret = 0;
1118 int scope = RT_SCOPE_NOWHERE;
1119 struct fib_info *prev_fi = NULL;
1120 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1121 struct hlist_head *head = &fib_info_devhash[hash];
1122 struct fib_nh *nh;
1123
1124 if (force)
1125 scope = -1;
1126
1127 hlist_for_each_entry(nh, head, nh_hash) {
1128 struct fib_info *fi = nh->nh_parent;
1129 int dead;
1130
1131 BUG_ON(!fi->fib_nhs);
1132 if (nh->nh_dev != dev || fi == prev_fi)
1133 continue;
1134 prev_fi = fi;
1135 dead = 0;
1136 change_nexthops(fi) {
1137 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1138 dead++;
1139 else if (nexthop_nh->nh_dev == dev &&
1140 nexthop_nh->nh_scope != scope) {
1141 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1142 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1143 spin_lock_bh(&fib_multipath_lock);
1144 fi->fib_power -= nexthop_nh->nh_power;
1145 nexthop_nh->nh_power = 0;
1146 spin_unlock_bh(&fib_multipath_lock);
1147 #endif
1148 dead++;
1149 }
1150 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1151 if (force > 1 && nexthop_nh->nh_dev == dev) {
1152 dead = fi->fib_nhs;
1153 break;
1154 }
1155 #endif
1156 } endfor_nexthops(fi)
1157 if (dead == fi->fib_nhs) {
1158 fi->fib_flags |= RTNH_F_DEAD;
1159 ret++;
1160 }
1161 }
1162
1163 return ret;
1164 }
1165
1166 /* Must be invoked inside of an RCU protected region. */
1167 void fib_select_default(struct fib_result *res)
1168 {
1169 struct fib_info *fi = NULL, *last_resort = NULL;
1170 struct list_head *fa_head = res->fa_head;
1171 struct fib_table *tb = res->table;
1172 int order = -1, last_idx = -1;
1173 struct fib_alias *fa;
1174
1175 list_for_each_entry_rcu(fa, fa_head, fa_list) {
1176 struct fib_info *next_fi = fa->fa_info;
1177
1178 if (next_fi->fib_scope != res->scope ||
1179 fa->fa_type != RTN_UNICAST)
1180 continue;
1181
1182 if (next_fi->fib_priority > res->fi->fib_priority)
1183 break;
1184 if (!next_fi->fib_nh[0].nh_gw ||
1185 next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1186 continue;
1187
1188 fib_alias_accessed(fa);
1189
1190 if (fi == NULL) {
1191 if (next_fi != res->fi)
1192 break;
1193 } else if (!fib_detect_death(fi, order, &last_resort,
1194 &last_idx, tb->tb_default)) {
1195 fib_result_assign(res, fi);
1196 tb->tb_default = order;
1197 goto out;
1198 }
1199 fi = next_fi;
1200 order++;
1201 }
1202
1203 if (order <= 0 || fi == NULL) {
1204 tb->tb_default = -1;
1205 goto out;
1206 }
1207
1208 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1209 tb->tb_default)) {
1210 fib_result_assign(res, fi);
1211 tb->tb_default = order;
1212 goto out;
1213 }
1214
1215 if (last_idx >= 0)
1216 fib_result_assign(res, last_resort);
1217 tb->tb_default = last_idx;
1218 out:
1219 return;
1220 }
1221
1222 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1223
1224 /*
1225 * Dead device goes up. We wake up dead nexthops.
1226 * It takes sense only on multipath routes.
1227 */
1228 int fib_sync_up(struct net_device *dev)
1229 {
1230 struct fib_info *prev_fi;
1231 unsigned int hash;
1232 struct hlist_head *head;
1233 struct fib_nh *nh;
1234 int ret;
1235
1236 if (!(dev->flags & IFF_UP))
1237 return 0;
1238
1239 prev_fi = NULL;
1240 hash = fib_devindex_hashfn(dev->ifindex);
1241 head = &fib_info_devhash[hash];
1242 ret = 0;
1243
1244 hlist_for_each_entry(nh, head, nh_hash) {
1245 struct fib_info *fi = nh->nh_parent;
1246 int alive;
1247
1248 BUG_ON(!fi->fib_nhs);
1249 if (nh->nh_dev != dev || fi == prev_fi)
1250 continue;
1251
1252 prev_fi = fi;
1253 alive = 0;
1254 change_nexthops(fi) {
1255 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1256 alive++;
1257 continue;
1258 }
1259 if (nexthop_nh->nh_dev == NULL ||
1260 !(nexthop_nh->nh_dev->flags & IFF_UP))
1261 continue;
1262 if (nexthop_nh->nh_dev != dev ||
1263 !__in_dev_get_rtnl(dev))
1264 continue;
1265 alive++;
1266 spin_lock_bh(&fib_multipath_lock);
1267 nexthop_nh->nh_power = 0;
1268 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1269 spin_unlock_bh(&fib_multipath_lock);
1270 } endfor_nexthops(fi)
1271
1272 if (alive > 0) {
1273 fi->fib_flags &= ~RTNH_F_DEAD;
1274 ret++;
1275 }
1276 }
1277
1278 return ret;
1279 }
1280
1281 /*
1282 * The algorithm is suboptimal, but it provides really
1283 * fair weighted route distribution.
1284 */
1285 void fib_select_multipath(struct fib_result *res)
1286 {
1287 struct fib_info *fi = res->fi;
1288 int w;
1289
1290 spin_lock_bh(&fib_multipath_lock);
1291 if (fi->fib_power <= 0) {
1292 int power = 0;
1293 change_nexthops(fi) {
1294 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1295 power += nexthop_nh->nh_weight;
1296 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1297 }
1298 } endfor_nexthops(fi);
1299 fi->fib_power = power;
1300 if (power <= 0) {
1301 spin_unlock_bh(&fib_multipath_lock);
1302 /* Race condition: route has just become dead. */
1303 res->nh_sel = 0;
1304 return;
1305 }
1306 }
1307
1308
1309 /* w should be random number [0..fi->fib_power-1],
1310 * it is pretty bad approximation.
1311 */
1312
1313 w = jiffies % fi->fib_power;
1314
1315 change_nexthops(fi) {
1316 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1317 nexthop_nh->nh_power) {
1318 w -= nexthop_nh->nh_power;
1319 if (w <= 0) {
1320 nexthop_nh->nh_power--;
1321 fi->fib_power--;
1322 res->nh_sel = nhsel;
1323 spin_unlock_bh(&fib_multipath_lock);
1324 return;
1325 }
1326 }
1327 } endfor_nexthops(fi);
1328
1329 /* Race condition: route has just become dead. */
1330 res->nh_sel = 0;
1331 spin_unlock_bh(&fib_multipath_lock);
1332 }
1333 #endif
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