?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Staging: hv: remove OnChildDeviceRemove vmbus_driver callback
[zen-stable.git] / net / ipv4 / fib_semantics.c
blob3e0da3ef6116df8b9b4fa6a70272ddeac8cac0d4
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 <asm/system.h>
18 #include <linux/bitops.h>
19 #include <linux/types.h>
20 #include <linux/kernel.h>
21 #include <linux/jiffies.h>
22 #include <linux/mm.h>
23 #include <linux/string.h>
24 #include <linux/socket.h>
25 #include <linux/sockios.h>
26 #include <linux/errno.h>
27 #include <linux/in.h>
28 #include <linux/inet.h>
29 #include <linux/inetdevice.h>
30 #include <linux/netdevice.h>
31 #include <linux/if_arp.h>
32 #include <linux/proc_fs.h>
33 #include <linux/skbuff.h>
34 #include <linux/init.h>
35 #include <linux/slab.h>
36
37 #include <net/arp.h>
38 #include <net/ip.h>
39 #include <net/protocol.h>
40 #include <net/route.h>
41 #include <net/tcp.h>
42 #include <net/sock.h>
43 #include <net/ip_fib.h>
44 #include <net/netlink.h>
45 #include <net/nexthop.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_hash_size;
53 static unsigned int fib_info_cnt;
54
55 #define DEVINDEX_HASHBITS 8
56 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59 #ifdef CONFIG_IP_ROUTE_MULTIPATH
60
61 static DEFINE_SPINLOCK(fib_multipath_lock);
62
63 #define for_nexthops(fi) { \
64 int nhsel; const struct fib_nh *nh; \
65 for (nhsel = 0, nh = (fi)->fib_nh; \
66 nhsel < (fi)->fib_nhs; \
67 nh++, nhsel++)
68
69 #define change_nexthops(fi) { \
70 int nhsel; struct fib_nh *nexthop_nh; \
71 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
72 nhsel < (fi)->fib_nhs; \
73 nexthop_nh++, nhsel++)
74
75 #else /* CONFIG_IP_ROUTE_MULTIPATH */
76
77 /* Hope, that gcc will optimize it to get rid of dummy loop */
78
79 #define for_nexthops(fi) { \
80 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
81 for (nhsel = 0; nhsel < 1; nhsel++)
82
83 #define change_nexthops(fi) { \
84 int nhsel; \
85 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
86 for (nhsel = 0; nhsel < 1; nhsel++)
87
88 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
89
90 #define endfor_nexthops(fi) }
91
92
93 static const struct
94 {
95 int error;
96 u8 scope;
97 } fib_props[RTN_MAX + 1] = {
98 [RTN_UNSPEC] = {
99 .error = 0,
100 .scope = RT_SCOPE_NOWHERE,
101 },
102 [RTN_UNICAST] = {
103 .error = 0,
104 .scope = RT_SCOPE_UNIVERSE,
105 },
106 [RTN_LOCAL] = {
107 .error = 0,
108 .scope = RT_SCOPE_HOST,
109 },
110 [RTN_BROADCAST] = {
111 .error = 0,
112 .scope = RT_SCOPE_LINK,
113 },
114 [RTN_ANYCAST] = {
115 .error = 0,
116 .scope = RT_SCOPE_LINK,
117 },
118 [RTN_MULTICAST] = {
119 .error = 0,
120 .scope = RT_SCOPE_UNIVERSE,
121 },
122 [RTN_BLACKHOLE] = {
123 .error = -EINVAL,
124 .scope = RT_SCOPE_UNIVERSE,
125 },
126 [RTN_UNREACHABLE] = {
127 .error = -EHOSTUNREACH,
128 .scope = RT_SCOPE_UNIVERSE,
129 },
130 [RTN_PROHIBIT] = {
131 .error = -EACCES,
132 .scope = RT_SCOPE_UNIVERSE,
133 },
134 [RTN_THROW] = {
135 .error = -EAGAIN,
136 .scope = RT_SCOPE_UNIVERSE,
137 },
138 [RTN_NAT] = {
139 .error = -EINVAL,
140 .scope = RT_SCOPE_NOWHERE,
141 },
142 [RTN_XRESOLVE] = {
143 .error = -EINVAL,
144 .scope = RT_SCOPE_NOWHERE,
145 },
146 };
147
148
149 /* Release a nexthop info record */
150
151 static void free_fib_info_rcu(struct rcu_head *head)
152 {
153 struct fib_info *fi = container_of(head, struct fib_info, rcu);
154
155 kfree(fi);
156 }
157
158 void free_fib_info(struct fib_info *fi)
159 {
160 if (fi->fib_dead == 0) {
161 pr_warning("Freeing alive fib_info %p\n", fi);
162 return;
163 }
164 change_nexthops(fi) {
165 if (nexthop_nh->nh_dev)
166 dev_put(nexthop_nh->nh_dev);
167 nexthop_nh->nh_dev = NULL;
168 } endfor_nexthops(fi);
169 fib_info_cnt--;
170 release_net(fi->fib_net);
171 call_rcu(&fi->rcu, free_fib_info_rcu);
172 }
173
174 void fib_release_info(struct fib_info *fi)
175 {
176 spin_lock_bh(&fib_info_lock);
177 if (fi && --fi->fib_treeref == 0) {
178 hlist_del(&fi->fib_hash);
179 if (fi->fib_prefsrc)
180 hlist_del(&fi->fib_lhash);
181 change_nexthops(fi) {
182 if (!nexthop_nh->nh_dev)
183 continue;
184 hlist_del(&nexthop_nh->nh_hash);
185 } endfor_nexthops(fi)
186 fi->fib_dead = 1;
187 fib_info_put(fi);
188 }
189 spin_unlock_bh(&fib_info_lock);
190 }
191
192 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
193 {
194 const struct fib_nh *onh = ofi->fib_nh;
195
196 for_nexthops(fi) {
197 if (nh->nh_oif != onh->nh_oif ||
198 nh->nh_gw != onh->nh_gw ||
199 nh->nh_scope != onh->nh_scope ||
200 #ifdef CONFIG_IP_ROUTE_MULTIPATH
201 nh->nh_weight != onh->nh_weight ||
202 #endif
203 #ifdef CONFIG_NET_CLS_ROUTE
204 nh->nh_tclassid != onh->nh_tclassid ||
205 #endif
206 ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
207 return -1;
208 onh++;
209 } endfor_nexthops(fi);
210 return 0;
211 }
212
213 static inline unsigned int fib_devindex_hashfn(unsigned int val)
214 {
215 unsigned int mask = DEVINDEX_HASHSIZE - 1;
216
217 return (val ^
218 (val >> DEVINDEX_HASHBITS) ^
219 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
220 }
221
222 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
223 {
224 unsigned int mask = (fib_hash_size - 1);
225 unsigned int val = fi->fib_nhs;
226
227 val ^= fi->fib_protocol;
228 val ^= (__force u32)fi->fib_prefsrc;
229 val ^= fi->fib_priority;
230 for_nexthops(fi) {
231 val ^= fib_devindex_hashfn(nh->nh_oif);
232 } endfor_nexthops(fi)
233
234 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
235 }
236
237 static struct fib_info *fib_find_info(const struct fib_info *nfi)
238 {
239 struct hlist_head *head;
240 struct hlist_node *node;
241 struct fib_info *fi;
242 unsigned int hash;
243
244 hash = fib_info_hashfn(nfi);
245 head = &fib_info_hash[hash];
246
247 hlist_for_each_entry(fi, node, head, fib_hash) {
248 if (!net_eq(fi->fib_net, nfi->fib_net))
249 continue;
250 if (fi->fib_nhs != nfi->fib_nhs)
251 continue;
252 if (nfi->fib_protocol == fi->fib_protocol &&
253 nfi->fib_prefsrc == fi->fib_prefsrc &&
254 nfi->fib_priority == fi->fib_priority &&
255 memcmp(nfi->fib_metrics, fi->fib_metrics,
256 sizeof(fi->fib_metrics)) == 0 &&
257 ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
258 (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
259 return fi;
260 }
261
262 return NULL;
263 }
264
265 /* Check, that the gateway is already configured.
266 * Used only by redirect accept routine.
267 */
268 int ip_fib_check_default(__be32 gw, struct net_device *dev)
269 {
270 struct hlist_head *head;
271 struct hlist_node *node;
272 struct fib_nh *nh;
273 unsigned int hash;
274
275 spin_lock(&fib_info_lock);
276
277 hash = fib_devindex_hashfn(dev->ifindex);
278 head = &fib_info_devhash[hash];
279 hlist_for_each_entry(nh, node, head, nh_hash) {
280 if (nh->nh_dev == dev &&
281 nh->nh_gw == gw &&
282 !(nh->nh_flags & RTNH_F_DEAD)) {
283 spin_unlock(&fib_info_lock);
284 return 0;
285 }
286 }
287
288 spin_unlock(&fib_info_lock);
289
290 return -1;
291 }
292
293 static inline size_t fib_nlmsg_size(struct fib_info *fi)
294 {
295 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
296 + nla_total_size(4) /* RTA_TABLE */
297 + nla_total_size(4) /* RTA_DST */
298 + nla_total_size(4) /* RTA_PRIORITY */
299 + nla_total_size(4); /* RTA_PREFSRC */
300
301 /* space for nested metrics */
302 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
303
304 if (fi->fib_nhs) {
305 /* Also handles the special case fib_nhs == 1 */
306
307 /* each nexthop is packed in an attribute */
308 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
309
310 /* may contain flow and gateway attribute */
311 nhsize += 2 * nla_total_size(4);
312
313 /* all nexthops are packed in a nested attribute */
314 payload += nla_total_size(fi->fib_nhs * nhsize);
315 }
316
317 return payload;
318 }
319
320 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
321 int dst_len, u32 tb_id, struct nl_info *info,
322 unsigned int nlm_flags)
323 {
324 struct sk_buff *skb;
325 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
326 int err = -ENOBUFS;
327
328 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
329 if (skb == NULL)
330 goto errout;
331
332 err = fib_dump_info(skb, info->pid, seq, event, tb_id,
333 fa->fa_type, fa->fa_scope, key, dst_len,
334 fa->fa_tos, fa->fa_info, nlm_flags);
335 if (err < 0) {
336 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
337 WARN_ON(err == -EMSGSIZE);
338 kfree_skb(skb);
339 goto errout;
340 }
341 rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
342 info->nlh, GFP_KERNEL);
343 return;
344 errout:
345 if (err < 0)
346 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
347 }
348
349 /* Return the first fib alias matching TOS with
350 * priority less than or equal to PRIO.
351 */
352 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
353 {
354 if (fah) {
355 struct fib_alias *fa;
356 list_for_each_entry(fa, fah, fa_list) {
357 if (fa->fa_tos > tos)
358 continue;
359 if (fa->fa_info->fib_priority >= prio ||
360 fa->fa_tos < tos)
361 return fa;
362 }
363 }
364 return NULL;
365 }
366
367 int fib_detect_death(struct fib_info *fi, int order,
368 struct fib_info **last_resort, int *last_idx, int dflt)
369 {
370 struct neighbour *n;
371 int state = NUD_NONE;
372
373 n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
374 if (n) {
375 state = n->nud_state;
376 neigh_release(n);
377 }
378 if (state == NUD_REACHABLE)
379 return 0;
380 if ((state & NUD_VALID) && order != dflt)
381 return 0;
382 if ((state & NUD_VALID) ||
383 (*last_idx < 0 && order > dflt)) {
384 *last_resort = fi;
385 *last_idx = order;
386 }
387 return 1;
388 }
389
390 #ifdef CONFIG_IP_ROUTE_MULTIPATH
391
392 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
393 {
394 int nhs = 0;
395
396 while (rtnh_ok(rtnh, remaining)) {
397 nhs++;
398 rtnh = rtnh_next(rtnh, &remaining);
399 }
400
401 /* leftover implies invalid nexthop configuration, discard it */
402 return remaining > 0 ? 0 : nhs;
403 }
404
405 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
406 int remaining, struct fib_config *cfg)
407 {
408 change_nexthops(fi) {
409 int attrlen;
410
411 if (!rtnh_ok(rtnh, remaining))
412 return -EINVAL;
413
414 nexthop_nh->nh_flags =
415 (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
416 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
417 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
418
419 attrlen = rtnh_attrlen(rtnh);
420 if (attrlen > 0) {
421 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
422
423 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
424 nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
425 #ifdef CONFIG_NET_CLS_ROUTE
426 nla = nla_find(attrs, attrlen, RTA_FLOW);
427 nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
428 #endif
429 }
430
431 rtnh = rtnh_next(rtnh, &remaining);
432 } endfor_nexthops(fi);
433
434 return 0;
435 }
436
437 #endif
438
439 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
440 {
441 #ifdef CONFIG_IP_ROUTE_MULTIPATH
442 struct rtnexthop *rtnh;
443 int remaining;
444 #endif
445
446 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
447 return 1;
448
449 if (cfg->fc_oif || cfg->fc_gw) {
450 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
451 (!cfg->fc_gw || cfg->fc_gw == fi->fib_nh->nh_gw))
452 return 0;
453 return 1;
454 }
455
456 #ifdef CONFIG_IP_ROUTE_MULTIPATH
457 if (cfg->fc_mp == NULL)
458 return 0;
459
460 rtnh = cfg->fc_mp;
461 remaining = cfg->fc_mp_len;
462
463 for_nexthops(fi) {
464 int attrlen;
465
466 if (!rtnh_ok(rtnh, remaining))
467 return -EINVAL;
468
469 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
470 return 1;
471
472 attrlen = rtnh_attrlen(rtnh);
473 if (attrlen < 0) {
474 struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
475
476 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
477 if (nla && nla_get_be32(nla) != nh->nh_gw)
478 return 1;
479 #ifdef CONFIG_NET_CLS_ROUTE
480 nla = nla_find(attrs, attrlen, RTA_FLOW);
481 if (nla && nla_get_u32(nla) != nh->nh_tclassid)
482 return 1;
483 #endif
484 }
485
486 rtnh = rtnh_next(rtnh, &remaining);
487 } endfor_nexthops(fi);
488 #endif
489 return 0;
490 }
491
492
493 /*
494 * Picture
495 * -------
496 *
497 * Semantics of nexthop is very messy by historical reasons.
498 * We have to take into account, that:
499 * a) gateway can be actually local interface address,
500 * so that gatewayed route is direct.
501 * b) gateway must be on-link address, possibly
502 * described not by an ifaddr, but also by a direct route.
503 * c) If both gateway and interface are specified, they should not
504 * contradict.
505 * d) If we use tunnel routes, gateway could be not on-link.
506 *
507 * Attempt to reconcile all of these (alas, self-contradictory) conditions
508 * results in pretty ugly and hairy code with obscure logic.
509 *
510 * I chose to generalized it instead, so that the size
511 * of code does not increase practically, but it becomes
512 * much more general.
513 * Every prefix is assigned a "scope" value: "host" is local address,
514 * "link" is direct route,
515 * [ ... "site" ... "interior" ... ]
516 * and "universe" is true gateway route with global meaning.
517 *
518 * Every prefix refers to a set of "nexthop"s (gw, oif),
519 * where gw must have narrower scope. This recursion stops
520 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
521 * which means that gw is forced to be on link.
522 *
523 * Code is still hairy, but now it is apparently logically
524 * consistent and very flexible. F.e. as by-product it allows
525 * to co-exists in peace independent exterior and interior
526 * routing processes.
527 *
528 * Normally it looks as following.
529 *
530 * {universe prefix} -> (gw, oif) [scope link]
531 * |
532 * |-> {link prefix} -> (gw, oif) [scope local]
533 * |
534 * |-> {local prefix} (terminal node)
535 */
536 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
537 struct fib_nh *nh)
538 {
539 int err;
540 struct net *net;
541 struct net_device *dev;
542
543 net = cfg->fc_nlinfo.nl_net;
544 if (nh->nh_gw) {
545 struct fib_result res;
546
547 if (nh->nh_flags & RTNH_F_ONLINK) {
548
549 if (cfg->fc_scope >= RT_SCOPE_LINK)
550 return -EINVAL;
551 if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
552 return -EINVAL;
553 dev = __dev_get_by_index(net, nh->nh_oif);
554 if (!dev)
555 return -ENODEV;
556 if (!(dev->flags & IFF_UP))
557 return -ENETDOWN;
558 nh->nh_dev = dev;
559 dev_hold(dev);
560 nh->nh_scope = RT_SCOPE_LINK;
561 return 0;
562 }
563 rcu_read_lock();
564 {
565 struct flowi fl = {
566 .nl_u = {
567 .ip4_u = {
568 .daddr = nh->nh_gw,
569 .scope = cfg->fc_scope + 1,
570 },
571 },
572 .oif = nh->nh_oif,
573 };
574
575 /* It is not necessary, but requires a bit of thinking */
576 if (fl.fl4_scope < RT_SCOPE_LINK)
577 fl.fl4_scope = RT_SCOPE_LINK;
578 err = fib_lookup(net, &fl, &res);
579 if (err) {
580 rcu_read_unlock();
581 return err;
582 }
583 }
584 err = -EINVAL;
585 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
586 goto out;
587 nh->nh_scope = res.scope;
588 nh->nh_oif = FIB_RES_OIF(res);
589 nh->nh_dev = dev = FIB_RES_DEV(res);
590 if (!dev)
591 goto out;
592 dev_hold(dev);
593 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
594 } else {
595 struct in_device *in_dev;
596
597 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
598 return -EINVAL;
599
600 rcu_read_lock();
601 err = -ENODEV;
602 in_dev = inetdev_by_index(net, nh->nh_oif);
603 if (in_dev == NULL)
604 goto out;
605 err = -ENETDOWN;
606 if (!(in_dev->dev->flags & IFF_UP))
607 goto out;
608 nh->nh_dev = in_dev->dev;
609 dev_hold(nh->nh_dev);
610 nh->nh_scope = RT_SCOPE_HOST;
611 err = 0;
612 }
613 out:
614 rcu_read_unlock();
615 return err;
616 }
617
618 static inline unsigned int fib_laddr_hashfn(__be32 val)
619 {
620 unsigned int mask = (fib_hash_size - 1);
621
622 return ((__force u32)val ^
623 ((__force u32)val >> 7) ^
624 ((__force u32)val >> 14)) & mask;
625 }
626
627 static struct hlist_head *fib_hash_alloc(int bytes)
628 {
629 if (bytes <= PAGE_SIZE)
630 return kzalloc(bytes, GFP_KERNEL);
631 else
632 return (struct hlist_head *)
633 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
634 get_order(bytes));
635 }
636
637 static void fib_hash_free(struct hlist_head *hash, int bytes)
638 {
639 if (!hash)
640 return;
641
642 if (bytes <= PAGE_SIZE)
643 kfree(hash);
644 else
645 free_pages((unsigned long) hash, get_order(bytes));
646 }
647
648 static void fib_hash_move(struct hlist_head *new_info_hash,
649 struct hlist_head *new_laddrhash,
650 unsigned int new_size)
651 {
652 struct hlist_head *old_info_hash, *old_laddrhash;
653 unsigned int old_size = fib_hash_size;
654 unsigned int i, bytes;
655
656 spin_lock_bh(&fib_info_lock);
657 old_info_hash = fib_info_hash;
658 old_laddrhash = fib_info_laddrhash;
659 fib_hash_size = new_size;
660
661 for (i = 0; i < old_size; i++) {
662 struct hlist_head *head = &fib_info_hash[i];
663 struct hlist_node *node, *n;
664 struct fib_info *fi;
665
666 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
667 struct hlist_head *dest;
668 unsigned int new_hash;
669
670 hlist_del(&fi->fib_hash);
671
672 new_hash = fib_info_hashfn(fi);
673 dest = &new_info_hash[new_hash];
674 hlist_add_head(&fi->fib_hash, dest);
675 }
676 }
677 fib_info_hash = new_info_hash;
678
679 for (i = 0; i < old_size; i++) {
680 struct hlist_head *lhead = &fib_info_laddrhash[i];
681 struct hlist_node *node, *n;
682 struct fib_info *fi;
683
684 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
685 struct hlist_head *ldest;
686 unsigned int new_hash;
687
688 hlist_del(&fi->fib_lhash);
689
690 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
691 ldest = &new_laddrhash[new_hash];
692 hlist_add_head(&fi->fib_lhash, ldest);
693 }
694 }
695 fib_info_laddrhash = new_laddrhash;
696
697 spin_unlock_bh(&fib_info_lock);
698
699 bytes = old_size * sizeof(struct hlist_head *);
700 fib_hash_free(old_info_hash, bytes);
701 fib_hash_free(old_laddrhash, bytes);
702 }
703
704 struct fib_info *fib_create_info(struct fib_config *cfg)
705 {
706 int err;
707 struct fib_info *fi = NULL;
708 struct fib_info *ofi;
709 int nhs = 1;
710 struct net *net = cfg->fc_nlinfo.nl_net;
711
712 /* Fast check to catch the most weird cases */
713 if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
714 goto err_inval;
715
716 #ifdef CONFIG_IP_ROUTE_MULTIPATH
717 if (cfg->fc_mp) {
718 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
719 if (nhs == 0)
720 goto err_inval;
721 }
722 #endif
723
724 err = -ENOBUFS;
725 if (fib_info_cnt >= fib_hash_size) {
726 unsigned int new_size = fib_hash_size << 1;
727 struct hlist_head *new_info_hash;
728 struct hlist_head *new_laddrhash;
729 unsigned int bytes;
730
731 if (!new_size)
732 new_size = 1;
733 bytes = new_size * sizeof(struct hlist_head *);
734 new_info_hash = fib_hash_alloc(bytes);
735 new_laddrhash = fib_hash_alloc(bytes);
736 if (!new_info_hash || !new_laddrhash) {
737 fib_hash_free(new_info_hash, bytes);
738 fib_hash_free(new_laddrhash, bytes);
739 } else
740 fib_hash_move(new_info_hash, new_laddrhash, new_size);
741
742 if (!fib_hash_size)
743 goto failure;
744 }
745
746 fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
747 if (fi == NULL)
748 goto failure;
749 fib_info_cnt++;
750
751 fi->fib_net = hold_net(net);
752 fi->fib_protocol = cfg->fc_protocol;
753 fi->fib_flags = cfg->fc_flags;
754 fi->fib_priority = cfg->fc_priority;
755 fi->fib_prefsrc = cfg->fc_prefsrc;
756
757 fi->fib_nhs = nhs;
758 change_nexthops(fi) {
759 nexthop_nh->nh_parent = fi;
760 } endfor_nexthops(fi)
761
762 if (cfg->fc_mx) {
763 struct nlattr *nla;
764 int remaining;
765
766 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
767 int type = nla_type(nla);
768
769 if (type) {
770 if (type > RTAX_MAX)
771 goto err_inval;
772 fi->fib_metrics[type - 1] = nla_get_u32(nla);
773 }
774 }
775 }
776
777 if (cfg->fc_mp) {
778 #ifdef CONFIG_IP_ROUTE_MULTIPATH
779 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
780 if (err != 0)
781 goto failure;
782 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
783 goto err_inval;
784 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
785 goto err_inval;
786 #ifdef CONFIG_NET_CLS_ROUTE
787 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
788 goto err_inval;
789 #endif
790 #else
791 goto err_inval;
792 #endif
793 } else {
794 struct fib_nh *nh = fi->fib_nh;
795
796 nh->nh_oif = cfg->fc_oif;
797 nh->nh_gw = cfg->fc_gw;
798 nh->nh_flags = cfg->fc_flags;
799 #ifdef CONFIG_NET_CLS_ROUTE
800 nh->nh_tclassid = cfg->fc_flow;
801 #endif
802 #ifdef CONFIG_IP_ROUTE_MULTIPATH
803 nh->nh_weight = 1;
804 #endif
805 }
806
807 if (fib_props[cfg->fc_type].error) {
808 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
809 goto err_inval;
810 goto link_it;
811 }
812
813 if (cfg->fc_scope > RT_SCOPE_HOST)
814 goto err_inval;
815
816 if (cfg->fc_scope == RT_SCOPE_HOST) {
817 struct fib_nh *nh = fi->fib_nh;
818
819 /* Local address is added. */
820 if (nhs != 1 || nh->nh_gw)
821 goto err_inval;
822 nh->nh_scope = RT_SCOPE_NOWHERE;
823 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
824 err = -ENODEV;
825 if (nh->nh_dev == NULL)
826 goto failure;
827 } else {
828 change_nexthops(fi) {
829 err = fib_check_nh(cfg, fi, nexthop_nh);
830 if (err != 0)
831 goto failure;
832 } endfor_nexthops(fi)
833 }
834
835 if (fi->fib_prefsrc) {
836 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
837 fi->fib_prefsrc != cfg->fc_dst)
838 if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
839 goto err_inval;
840 }
841
842 link_it:
843 ofi = fib_find_info(fi);
844 if (ofi) {
845 fi->fib_dead = 1;
846 free_fib_info(fi);
847 ofi->fib_treeref++;
848 return ofi;
849 }
850
851 fi->fib_treeref++;
852 atomic_inc(&fi->fib_clntref);
853 spin_lock_bh(&fib_info_lock);
854 hlist_add_head(&fi->fib_hash,
855 &fib_info_hash[fib_info_hashfn(fi)]);
856 if (fi->fib_prefsrc) {
857 struct hlist_head *head;
858
859 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
860 hlist_add_head(&fi->fib_lhash, head);
861 }
862 change_nexthops(fi) {
863 struct hlist_head *head;
864 unsigned int hash;
865
866 if (!nexthop_nh->nh_dev)
867 continue;
868 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
869 head = &fib_info_devhash[hash];
870 hlist_add_head(&nexthop_nh->nh_hash, head);
871 } endfor_nexthops(fi)
872 spin_unlock_bh(&fib_info_lock);
873 return fi;
874
875 err_inval:
876 err = -EINVAL;
877
878 failure:
879 if (fi) {
880 fi->fib_dead = 1;
881 free_fib_info(fi);
882 }
883
884 return ERR_PTR(err);
885 }
886
887 /* Note! fib_semantic_match intentionally uses RCU list functions. */
888 int fib_semantic_match(struct list_head *head, const struct flowi *flp,
889 struct fib_result *res, int prefixlen, int fib_flags)
890 {
891 struct fib_alias *fa;
892 int nh_sel = 0;
893
894 list_for_each_entry_rcu(fa, head, fa_list) {
895 int err;
896
897 if (fa->fa_tos &&
898 fa->fa_tos != flp->fl4_tos)
899 continue;
900
901 if (fa->fa_scope < flp->fl4_scope)
902 continue;
903
904 fib_alias_accessed(fa);
905
906 err = fib_props[fa->fa_type].error;
907 if (err == 0) {
908 struct fib_info *fi = fa->fa_info;
909
910 if (fi->fib_flags & RTNH_F_DEAD)
911 continue;
912
913 switch (fa->fa_type) {
914 case RTN_UNICAST:
915 case RTN_LOCAL:
916 case RTN_BROADCAST:
917 case RTN_ANYCAST:
918 case RTN_MULTICAST:
919 for_nexthops(fi) {
920 if (nh->nh_flags & RTNH_F_DEAD)
921 continue;
922 if (!flp->oif || flp->oif == nh->nh_oif)
923 break;
924 }
925 #ifdef CONFIG_IP_ROUTE_MULTIPATH
926 if (nhsel < fi->fib_nhs) {
927 nh_sel = nhsel;
928 goto out_fill_res;
929 }
930 #else
931 if (nhsel < 1)
932 goto out_fill_res;
933 #endif
934 endfor_nexthops(fi);
935 continue;
936
937 default:
938 pr_warning("fib_semantic_match bad type %#x\n",
939 fa->fa_type);
940 return -EINVAL;
941 }
942 }
943 return err;
944 }
945 return 1;
946
947 out_fill_res:
948 res->prefixlen = prefixlen;
949 res->nh_sel = nh_sel;
950 res->type = fa->fa_type;
951 res->scope = fa->fa_scope;
952 res->fi = fa->fa_info;
953 if (!(fib_flags & FIB_LOOKUP_NOREF))
954 atomic_inc(&res->fi->fib_clntref);
955 return 0;
956 }
957
958 /* Find appropriate source address to this destination */
959
960 __be32 __fib_res_prefsrc(struct fib_result *res)
961 {
962 return inet_select_addr(FIB_RES_DEV(*res), FIB_RES_GW(*res), res->scope);
963 }
964
965 int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
966 u32 tb_id, u8 type, u8 scope, __be32 dst, int dst_len, u8 tos,
967 struct fib_info *fi, unsigned int flags)
968 {
969 struct nlmsghdr *nlh;
970 struct rtmsg *rtm;
971
972 nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
973 if (nlh == NULL)
974 return -EMSGSIZE;
975
976 rtm = nlmsg_data(nlh);
977 rtm->rtm_family = AF_INET;
978 rtm->rtm_dst_len = dst_len;
979 rtm->rtm_src_len = 0;
980 rtm->rtm_tos = tos;
981 if (tb_id < 256)
982 rtm->rtm_table = tb_id;
983 else
984 rtm->rtm_table = RT_TABLE_COMPAT;
985 NLA_PUT_U32(skb, RTA_TABLE, tb_id);
986 rtm->rtm_type = type;
987 rtm->rtm_flags = fi->fib_flags;
988 rtm->rtm_scope = scope;
989 rtm->rtm_protocol = fi->fib_protocol;
990
991 if (rtm->rtm_dst_len)
992 NLA_PUT_BE32(skb, RTA_DST, dst);
993
994 if (fi->fib_priority)
995 NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
996
997 if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
998 goto nla_put_failure;
999
1000 if (fi->fib_prefsrc)
1001 NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc);
1002
1003 if (fi->fib_nhs == 1) {
1004 if (fi->fib_nh->nh_gw)
1005 NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
1006
1007 if (fi->fib_nh->nh_oif)
1008 NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
1009 #ifdef CONFIG_NET_CLS_ROUTE
1010 if (fi->fib_nh[0].nh_tclassid)
1011 NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
1012 #endif
1013 }
1014 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1015 if (fi->fib_nhs > 1) {
1016 struct rtnexthop *rtnh;
1017 struct nlattr *mp;
1018
1019 mp = nla_nest_start(skb, RTA_MULTIPATH);
1020 if (mp == NULL)
1021 goto nla_put_failure;
1022
1023 for_nexthops(fi) {
1024 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1025 if (rtnh == NULL)
1026 goto nla_put_failure;
1027
1028 rtnh->rtnh_flags = nh->nh_flags & 0xFF;
1029 rtnh->rtnh_hops = nh->nh_weight - 1;
1030 rtnh->rtnh_ifindex = nh->nh_oif;
1031
1032 if (nh->nh_gw)
1033 NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw);
1034 #ifdef CONFIG_NET_CLS_ROUTE
1035 if (nh->nh_tclassid)
1036 NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
1037 #endif
1038 /* length of rtnetlink header + attributes */
1039 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
1040 } endfor_nexthops(fi);
1041
1042 nla_nest_end(skb, mp);
1043 }
1044 #endif
1045 return nlmsg_end(skb, nlh);
1046
1047 nla_put_failure:
1048 nlmsg_cancel(skb, nlh);
1049 return -EMSGSIZE;
1050 }
1051
1052 /*
1053 * Update FIB if:
1054 * - local address disappeared -> we must delete all the entries
1055 * referring to it.
1056 * - device went down -> we must shutdown all nexthops going via it.
1057 */
1058 int fib_sync_down_addr(struct net *net, __be32 local)
1059 {
1060 int ret = 0;
1061 unsigned int hash = fib_laddr_hashfn(local);
1062 struct hlist_head *head = &fib_info_laddrhash[hash];
1063 struct hlist_node *node;
1064 struct fib_info *fi;
1065
1066 if (fib_info_laddrhash == NULL || local == 0)
1067 return 0;
1068
1069 hlist_for_each_entry(fi, node, head, fib_lhash) {
1070 if (!net_eq(fi->fib_net, net))
1071 continue;
1072 if (fi->fib_prefsrc == local) {
1073 fi->fib_flags |= RTNH_F_DEAD;
1074 ret++;
1075 }
1076 }
1077 return ret;
1078 }
1079
1080 int fib_sync_down_dev(struct net_device *dev, int force)
1081 {
1082 int ret = 0;
1083 int scope = RT_SCOPE_NOWHERE;
1084 struct fib_info *prev_fi = NULL;
1085 unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1086 struct hlist_head *head = &fib_info_devhash[hash];
1087 struct hlist_node *node;
1088 struct fib_nh *nh;
1089
1090 if (force)
1091 scope = -1;
1092
1093 hlist_for_each_entry(nh, node, head, nh_hash) {
1094 struct fib_info *fi = nh->nh_parent;
1095 int dead;
1096
1097 BUG_ON(!fi->fib_nhs);
1098 if (nh->nh_dev != dev || fi == prev_fi)
1099 continue;
1100 prev_fi = fi;
1101 dead = 0;
1102 change_nexthops(fi) {
1103 if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1104 dead++;
1105 else if (nexthop_nh->nh_dev == dev &&
1106 nexthop_nh->nh_scope != scope) {
1107 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1108 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1109 spin_lock_bh(&fib_multipath_lock);
1110 fi->fib_power -= nexthop_nh->nh_power;
1111 nexthop_nh->nh_power = 0;
1112 spin_unlock_bh(&fib_multipath_lock);
1113 #endif
1114 dead++;
1115 }
1116 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1117 if (force > 1 && nexthop_nh->nh_dev == dev) {
1118 dead = fi->fib_nhs;
1119 break;
1120 }
1121 #endif
1122 } endfor_nexthops(fi)
1123 if (dead == fi->fib_nhs) {
1124 fi->fib_flags |= RTNH_F_DEAD;
1125 ret++;
1126 }
1127 }
1128
1129 return ret;
1130 }
1131
1132 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1133
1134 /*
1135 * Dead device goes up. We wake up dead nexthops.
1136 * It takes sense only on multipath routes.
1137 */
1138 int fib_sync_up(struct net_device *dev)
1139 {
1140 struct fib_info *prev_fi;
1141 unsigned int hash;
1142 struct hlist_head *head;
1143 struct hlist_node *node;
1144 struct fib_nh *nh;
1145 int ret;
1146
1147 if (!(dev->flags & IFF_UP))
1148 return 0;
1149
1150 prev_fi = NULL;
1151 hash = fib_devindex_hashfn(dev->ifindex);
1152 head = &fib_info_devhash[hash];
1153 ret = 0;
1154
1155 hlist_for_each_entry(nh, node, head, nh_hash) {
1156 struct fib_info *fi = nh->nh_parent;
1157 int alive;
1158
1159 BUG_ON(!fi->fib_nhs);
1160 if (nh->nh_dev != dev || fi == prev_fi)
1161 continue;
1162
1163 prev_fi = fi;
1164 alive = 0;
1165 change_nexthops(fi) {
1166 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1167 alive++;
1168 continue;
1169 }
1170 if (nexthop_nh->nh_dev == NULL ||
1171 !(nexthop_nh->nh_dev->flags & IFF_UP))
1172 continue;
1173 if (nexthop_nh->nh_dev != dev ||
1174 !__in_dev_get_rtnl(dev))
1175 continue;
1176 alive++;
1177 spin_lock_bh(&fib_multipath_lock);
1178 nexthop_nh->nh_power = 0;
1179 nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1180 spin_unlock_bh(&fib_multipath_lock);
1181 } endfor_nexthops(fi)
1182
1183 if (alive > 0) {
1184 fi->fib_flags &= ~RTNH_F_DEAD;
1185 ret++;
1186 }
1187 }
1188
1189 return ret;
1190 }
1191
1192 /*
1193 * The algorithm is suboptimal, but it provides really
1194 * fair weighted route distribution.
1195 */
1196 void fib_select_multipath(const struct flowi *flp, struct fib_result *res)
1197 {
1198 struct fib_info *fi = res->fi;
1199 int w;
1200
1201 spin_lock_bh(&fib_multipath_lock);
1202 if (fi->fib_power <= 0) {
1203 int power = 0;
1204 change_nexthops(fi) {
1205 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1206 power += nexthop_nh->nh_weight;
1207 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1208 }
1209 } endfor_nexthops(fi);
1210 fi->fib_power = power;
1211 if (power <= 0) {
1212 spin_unlock_bh(&fib_multipath_lock);
1213 /* Race condition: route has just become dead. */
1214 res->nh_sel = 0;
1215 return;
1216 }
1217 }
1218
1219
1220 /* w should be random number [0..fi->fib_power-1],
1221 * it is pretty bad approximation.
1222 */
1223
1224 w = jiffies % fi->fib_power;
1225
1226 change_nexthops(fi) {
1227 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1228 nexthop_nh->nh_power) {
1229 w -= nexthop_nh->nh_power;
1230 if (w <= 0) {
1231 nexthop_nh->nh_power--;
1232 fi->fib_power--;
1233 res->nh_sel = nhsel;
1234 spin_unlock_bh(&fib_multipath_lock);
1235 return;
1236 }
1237 }
1238 } endfor_nexthops(fi);
1239
1240 /* Race condition: route has just become dead. */
1241 res->nh_sel = 0;
1242 spin_unlock_bh(&fib_multipath_lock);
1243 }
1244 #endif