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