ipv4: Inline fib_semantic_match into check_leaf
[linux-3.10.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 <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_info_hash_size;
53 static unsigned int fib_info_cnt;
54
55 #define DEVINDEX_HASHBITS 8
56 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
57 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
58
59 #ifdef CONFIG_IP_ROUTE_MULTIPATH
60
61 static DEFINE_SPINLOCK(fib_multipath_lock);
62
63 #define for_nexthops(fi) {                                              \
64         int nhsel; const struct fib_nh *nh;                             \
65         for (nhsel = 0, nh = (fi)->fib_nh;                              \
66              nhsel < (fi)->fib_nhs;                                     \
67              nh++, nhsel++)
68
69 #define change_nexthops(fi) {                                           \
70         int nhsel; struct fib_nh *nexthop_nh;                           \
71         for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh);   \
72              nhsel < (fi)->fib_nhs;                                     \
73              nexthop_nh++, nhsel++)
74
75 #else /* CONFIG_IP_ROUTE_MULTIPATH */
76
77 /* Hope, that gcc will optimize it to get rid of dummy loop */
78
79 #define for_nexthops(fi) {                                              \
80         int nhsel; const struct fib_nh *nh = (fi)->fib_nh;              \
81         for (nhsel = 0; nhsel < 1; nhsel++)
82
83 #define change_nexthops(fi) {                                           \
84         int nhsel;                                                      \
85         struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh);    \
86         for (nhsel = 0; nhsel < 1; nhsel++)
87
88 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
89
90 #define endfor_nexthops(fi) }
91
92
93 const struct fib_prop fib_props[RTN_MAX + 1] = {
94         [RTN_UNSPEC] = {
95                 .error  = 0,
96                 .scope  = RT_SCOPE_NOWHERE,
97         },
98         [RTN_UNICAST] = {
99                 .error  = 0,
100                 .scope  = RT_SCOPE_UNIVERSE,
101         },
102         [RTN_LOCAL] = {
103                 .error  = 0,
104                 .scope  = RT_SCOPE_HOST,
105         },
106         [RTN_BROADCAST] = {
107                 .error  = 0,
108                 .scope  = RT_SCOPE_LINK,
109         },
110         [RTN_ANYCAST] = {
111                 .error  = 0,
112                 .scope  = RT_SCOPE_LINK,
113         },
114         [RTN_MULTICAST] = {
115                 .error  = 0,
116                 .scope  = RT_SCOPE_UNIVERSE,
117         },
118         [RTN_BLACKHOLE] = {
119                 .error  = -EINVAL,
120                 .scope  = RT_SCOPE_UNIVERSE,
121         },
122         [RTN_UNREACHABLE] = {
123                 .error  = -EHOSTUNREACH,
124                 .scope  = RT_SCOPE_UNIVERSE,
125         },
126         [RTN_PROHIBIT] = {
127                 .error  = -EACCES,
128                 .scope  = RT_SCOPE_UNIVERSE,
129         },
130         [RTN_THROW] = {
131                 .error  = -EAGAIN,
132                 .scope  = RT_SCOPE_UNIVERSE,
133         },
134         [RTN_NAT] = {
135                 .error  = -EINVAL,
136                 .scope  = RT_SCOPE_NOWHERE,
137         },
138         [RTN_XRESOLVE] = {
139                 .error  = -EINVAL,
140                 .scope  = RT_SCOPE_NOWHERE,
141         },
142 };
143
144
145 /* Release a nexthop info record */
146
147 static void free_fib_info_rcu(struct rcu_head *head)
148 {
149         struct fib_info *fi = container_of(head, struct fib_info, rcu);
150
151         if (fi->fib_metrics != (u32 *) dst_default_metrics)
152                 kfree(fi->fib_metrics);
153         kfree(fi);
154 }
155
156 void free_fib_info(struct fib_info *fi)
157 {
158         if (fi->fib_dead == 0) {
159                 pr_warning("Freeing alive fib_info %p\n", fi);
160                 return;
161         }
162         change_nexthops(fi) {
163                 if (nexthop_nh->nh_dev)
164                         dev_put(nexthop_nh->nh_dev);
165                 nexthop_nh->nh_dev = NULL;
166         } endfor_nexthops(fi);
167         fib_info_cnt--;
168         release_net(fi->fib_net);
169         call_rcu(&fi->rcu, free_fib_info_rcu);
170 }
171
172 void fib_release_info(struct fib_info *fi)
173 {
174         spin_lock_bh(&fib_info_lock);
175         if (fi && --fi->fib_treeref == 0) {
176                 hlist_del(&fi->fib_hash);
177                 if (fi->fib_prefsrc)
178                         hlist_del(&fi->fib_lhash);
179                 change_nexthops(fi) {
180                         if (!nexthop_nh->nh_dev)
181                                 continue;
182                         hlist_del(&nexthop_nh->nh_hash);
183                 } endfor_nexthops(fi)
184                 fi->fib_dead = 1;
185                 fib_info_put(fi);
186         }
187         spin_unlock_bh(&fib_info_lock);
188 }
189
190 static inline int nh_comp(const struct fib_info *fi, const struct fib_info *ofi)
191 {
192         const struct fib_nh *onh = ofi->fib_nh;
193
194         for_nexthops(fi) {
195                 if (nh->nh_oif != onh->nh_oif ||
196                     nh->nh_gw  != onh->nh_gw ||
197                     nh->nh_scope != onh->nh_scope ||
198 #ifdef CONFIG_IP_ROUTE_MULTIPATH
199                     nh->nh_weight != onh->nh_weight ||
200 #endif
201 #ifdef CONFIG_IP_ROUTE_CLASSID
202                     nh->nh_tclassid != onh->nh_tclassid ||
203 #endif
204                     ((nh->nh_flags ^ onh->nh_flags) & ~RTNH_F_DEAD))
205                         return -1;
206                 onh++;
207         } endfor_nexthops(fi);
208         return 0;
209 }
210
211 static inline unsigned int fib_devindex_hashfn(unsigned int val)
212 {
213         unsigned int mask = DEVINDEX_HASHSIZE - 1;
214
215         return (val ^
216                 (val >> DEVINDEX_HASHBITS) ^
217                 (val >> (DEVINDEX_HASHBITS * 2))) & mask;
218 }
219
220 static inline unsigned int fib_info_hashfn(const struct fib_info *fi)
221 {
222         unsigned int mask = (fib_info_hash_size - 1);
223         unsigned int val = fi->fib_nhs;
224
225         val ^= fi->fib_protocol;
226         val ^= (__force u32)fi->fib_prefsrc;
227         val ^= fi->fib_priority;
228         for_nexthops(fi) {
229                 val ^= fib_devindex_hashfn(nh->nh_oif);
230         } endfor_nexthops(fi)
231
232         return (val ^ (val >> 7) ^ (val >> 12)) & mask;
233 }
234
235 static struct fib_info *fib_find_info(const struct fib_info *nfi)
236 {
237         struct hlist_head *head;
238         struct hlist_node *node;
239         struct fib_info *fi;
240         unsigned int hash;
241
242         hash = fib_info_hashfn(nfi);
243         head = &fib_info_hash[hash];
244
245         hlist_for_each_entry(fi, node, head, fib_hash) {
246                 if (!net_eq(fi->fib_net, nfi->fib_net))
247                         continue;
248                 if (fi->fib_nhs != nfi->fib_nhs)
249                         continue;
250                 if (nfi->fib_protocol == fi->fib_protocol &&
251                     nfi->fib_prefsrc == fi->fib_prefsrc &&
252                     nfi->fib_priority == fi->fib_priority &&
253                     memcmp(nfi->fib_metrics, fi->fib_metrics,
254                            sizeof(fi->fib_metrics)) == 0 &&
255                     ((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_F_DEAD) == 0 &&
256                     (nfi->fib_nhs == 0 || nh_comp(fi, nfi) == 0))
257                         return fi;
258         }
259
260         return NULL;
261 }
262
263 /* Check, that the gateway is already configured.
264  * Used only by redirect accept routine.
265  */
266 int ip_fib_check_default(__be32 gw, struct net_device *dev)
267 {
268         struct hlist_head *head;
269         struct hlist_node *node;
270         struct fib_nh *nh;
271         unsigned int hash;
272
273         spin_lock(&fib_info_lock);
274
275         hash = fib_devindex_hashfn(dev->ifindex);
276         head = &fib_info_devhash[hash];
277         hlist_for_each_entry(nh, node, head, nh_hash) {
278                 if (nh->nh_dev == dev &&
279                     nh->nh_gw == gw &&
280                     !(nh->nh_flags & RTNH_F_DEAD)) {
281                         spin_unlock(&fib_info_lock);
282                         return 0;
283                 }
284         }
285
286         spin_unlock(&fib_info_lock);
287
288         return -1;
289 }
290
291 static inline size_t fib_nlmsg_size(struct fib_info *fi)
292 {
293         size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
294                          + nla_total_size(4) /* RTA_TABLE */
295                          + nla_total_size(4) /* RTA_DST */
296                          + nla_total_size(4) /* RTA_PRIORITY */
297                          + nla_total_size(4); /* RTA_PREFSRC */
298
299         /* space for nested metrics */
300         payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
301
302         if (fi->fib_nhs) {
303                 /* Also handles the special case fib_nhs == 1 */
304
305                 /* each nexthop is packed in an attribute */
306                 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
307
308                 /* may contain flow and gateway attribute */
309                 nhsize += 2 * nla_total_size(4);
310
311                 /* all nexthops are packed in a nested attribute */
312                 payload += nla_total_size(fi->fib_nhs * nhsize);
313         }
314
315         return payload;
316 }
317
318 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
319                int dst_len, u32 tb_id, struct nl_info *info,
320                unsigned int nlm_flags)
321 {
322         struct sk_buff *skb;
323         u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
324         int err = -ENOBUFS;
325
326         skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
327         if (skb == NULL)
328                 goto errout;
329
330         err = fib_dump_info(skb, info->pid, seq, event, tb_id,
331                             fa->fa_type, fa->fa_scope, key, dst_len,
332                             fa->fa_tos, fa->fa_info, nlm_flags);
333         if (err < 0) {
334                 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
335                 WARN_ON(err == -EMSGSIZE);
336                 kfree_skb(skb);
337                 goto errout;
338         }
339         rtnl_notify(skb, info->nl_net, info->pid, RTNLGRP_IPV4_ROUTE,
340                     info->nlh, GFP_KERNEL);
341         return;
342 errout:
343         if (err < 0)
344                 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
345 }
346
347 /* Return the first fib alias matching TOS with
348  * priority less than or equal to PRIO.
349  */
350 struct fib_alias *fib_find_alias(struct list_head *fah, u8 tos, u32 prio)
351 {
352         if (fah) {
353                 struct fib_alias *fa;
354                 list_for_each_entry(fa, fah, fa_list) {
355                         if (fa->fa_tos > tos)
356                                 continue;
357                         if (fa->fa_info->fib_priority >= prio ||
358                             fa->fa_tos < tos)
359                                 return fa;
360                 }
361         }
362         return NULL;
363 }
364
365 int fib_detect_death(struct fib_info *fi, int order,
366                      struct fib_info **last_resort, int *last_idx, int dflt)
367 {
368         struct neighbour *n;
369         int state = NUD_NONE;
370
371         n = neigh_lookup(&arp_tbl, &fi->fib_nh[0].nh_gw, fi->fib_dev);
372         if (n) {
373                 state = n->nud_state;
374                 neigh_release(n);
375         }
376         if (state == NUD_REACHABLE)
377                 return 0;
378         if ((state & NUD_VALID) && order != dflt)
379                 return 0;
380         if ((state & NUD_VALID) ||
381             (*last_idx < 0 && order > dflt)) {
382                 *last_resort = fi;
383                 *last_idx = order;
384         }
385         return 1;
386 }
387
388 #ifdef CONFIG_IP_ROUTE_MULTIPATH
389
390 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
391 {
392         int nhs = 0;
393
394         while (rtnh_ok(rtnh, remaining)) {
395                 nhs++;
396                 rtnh = rtnh_next(rtnh, &remaining);
397         }
398
399         /* leftover implies invalid nexthop configuration, discard it */
400         return remaining > 0 ? 0 : nhs;
401 }
402
403 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
404                        int remaining, struct fib_config *cfg)
405 {
406         change_nexthops(fi) {
407                 int attrlen;
408
409                 if (!rtnh_ok(rtnh, remaining))
410                         return -EINVAL;
411
412                 nexthop_nh->nh_flags =
413                         (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
414                 nexthop_nh->nh_oif = rtnh->rtnh_ifindex;
415                 nexthop_nh->nh_weight = rtnh->rtnh_hops + 1;
416
417                 attrlen = rtnh_attrlen(rtnh);
418                 if (attrlen > 0) {
419                         struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
420
421                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
422                         nexthop_nh->nh_gw = nla ? nla_get_be32(nla) : 0;
423 #ifdef CONFIG_IP_ROUTE_CLASSID
424                         nla = nla_find(attrs, attrlen, RTA_FLOW);
425                         nexthop_nh->nh_tclassid = nla ? nla_get_u32(nla) : 0;
426 #endif
427                 }
428
429                 rtnh = rtnh_next(rtnh, &remaining);
430         } endfor_nexthops(fi);
431
432         return 0;
433 }
434
435 #endif
436
437 int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
438 {
439 #ifdef CONFIG_IP_ROUTE_MULTIPATH
440         struct rtnexthop *rtnh;
441         int remaining;
442 #endif
443
444         if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
445                 return 1;
446
447         if (cfg->fc_oif || cfg->fc_gw) {
448                 if ((!cfg->fc_oif || cfg->fc_oif == fi->fib_nh->nh_oif) &&
449                     (!cfg->fc_gw  || cfg->fc_gw == fi->fib_nh->nh_gw))
450                         return 0;
451                 return 1;
452         }
453
454 #ifdef CONFIG_IP_ROUTE_MULTIPATH
455         if (cfg->fc_mp == NULL)
456                 return 0;
457
458         rtnh = cfg->fc_mp;
459         remaining = cfg->fc_mp_len;
460
461         for_nexthops(fi) {
462                 int attrlen;
463
464                 if (!rtnh_ok(rtnh, remaining))
465                         return -EINVAL;
466
467                 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->nh_oif)
468                         return 1;
469
470                 attrlen = rtnh_attrlen(rtnh);
471                 if (attrlen < 0) {
472                         struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
473
474                         nla = nla_find(attrs, attrlen, RTA_GATEWAY);
475                         if (nla && nla_get_be32(nla) != nh->nh_gw)
476                                 return 1;
477 #ifdef CONFIG_IP_ROUTE_CLASSID
478                         nla = nla_find(attrs, attrlen, RTA_FLOW);
479                         if (nla && nla_get_u32(nla) != nh->nh_tclassid)
480                                 return 1;
481 #endif
482                 }
483
484                 rtnh = rtnh_next(rtnh, &remaining);
485         } endfor_nexthops(fi);
486 #endif
487         return 0;
488 }
489
490
491 /*
492  * Picture
493  * -------
494  *
495  * Semantics of nexthop is very messy by historical reasons.
496  * We have to take into account, that:
497  * a) gateway can be actually local interface address,
498  *    so that gatewayed route is direct.
499  * b) gateway must be on-link address, possibly
500  *    described not by an ifaddr, but also by a direct route.
501  * c) If both gateway and interface are specified, they should not
502  *    contradict.
503  * d) If we use tunnel routes, gateway could be not on-link.
504  *
505  * Attempt to reconcile all of these (alas, self-contradictory) conditions
506  * results in pretty ugly and hairy code with obscure logic.
507  *
508  * I chose to generalized it instead, so that the size
509  * of code does not increase practically, but it becomes
510  * much more general.
511  * Every prefix is assigned a "scope" value: "host" is local address,
512  * "link" is direct route,
513  * [ ... "site" ... "interior" ... ]
514  * and "universe" is true gateway route with global meaning.
515  *
516  * Every prefix refers to a set of "nexthop"s (gw, oif),
517  * where gw must have narrower scope. This recursion stops
518  * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
519  * which means that gw is forced to be on link.
520  *
521  * Code is still hairy, but now it is apparently logically
522  * consistent and very flexible. F.e. as by-product it allows
523  * to co-exists in peace independent exterior and interior
524  * routing processes.
525  *
526  * Normally it looks as following.
527  *
528  * {universe prefix}  -> (gw, oif) [scope link]
529  *                |
530  *                |-> {link prefix} -> (gw, oif) [scope local]
531  *                                      |
532  *                                      |-> {local prefix} (terminal node)
533  */
534 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
535                         struct fib_nh *nh)
536 {
537         int err;
538         struct net *net;
539         struct net_device *dev;
540
541         net = cfg->fc_nlinfo.nl_net;
542         if (nh->nh_gw) {
543                 struct fib_result res;
544
545                 if (nh->nh_flags & RTNH_F_ONLINK) {
546
547                         if (cfg->fc_scope >= RT_SCOPE_LINK)
548                                 return -EINVAL;
549                         if (inet_addr_type(net, nh->nh_gw) != RTN_UNICAST)
550                                 return -EINVAL;
551                         dev = __dev_get_by_index(net, nh->nh_oif);
552                         if (!dev)
553                                 return -ENODEV;
554                         if (!(dev->flags & IFF_UP))
555                                 return -ENETDOWN;
556                         nh->nh_dev = dev;
557                         dev_hold(dev);
558                         nh->nh_scope = RT_SCOPE_LINK;
559                         return 0;
560                 }
561                 rcu_read_lock();
562                 {
563                         struct flowi fl = {
564                                 .fl4_dst = nh->nh_gw,
565                                 .fl4_scope = cfg->fc_scope + 1,
566                                 .oif = nh->nh_oif,
567                         };
568
569                         /* It is not necessary, but requires a bit of thinking */
570                         if (fl.fl4_scope < RT_SCOPE_LINK)
571                                 fl.fl4_scope = RT_SCOPE_LINK;
572                         err = fib_lookup(net, &fl, &res);
573                         if (err) {
574                                 rcu_read_unlock();
575                                 return err;
576                         }
577                 }
578                 err = -EINVAL;
579                 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
580                         goto out;
581                 nh->nh_scope = res.scope;
582                 nh->nh_oif = FIB_RES_OIF(res);
583                 nh->nh_dev = dev = FIB_RES_DEV(res);
584                 if (!dev)
585                         goto out;
586                 dev_hold(dev);
587                 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
588         } else {
589                 struct in_device *in_dev;
590
591                 if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
592                         return -EINVAL;
593
594                 rcu_read_lock();
595                 err = -ENODEV;
596                 in_dev = inetdev_by_index(net, nh->nh_oif);
597                 if (in_dev == NULL)
598                         goto out;
599                 err = -ENETDOWN;
600                 if (!(in_dev->dev->flags & IFF_UP))
601                         goto out;
602                 nh->nh_dev = in_dev->dev;
603                 dev_hold(nh->nh_dev);
604                 nh->nh_scope = RT_SCOPE_HOST;
605                 err = 0;
606         }
607 out:
608         rcu_read_unlock();
609         return err;
610 }
611
612 static inline unsigned int fib_laddr_hashfn(__be32 val)
613 {
614         unsigned int mask = (fib_info_hash_size - 1);
615
616         return ((__force u32)val ^
617                 ((__force u32)val >> 7) ^
618                 ((__force u32)val >> 14)) & mask;
619 }
620
621 static struct hlist_head *fib_info_hash_alloc(int bytes)
622 {
623         if (bytes <= PAGE_SIZE)
624                 return kzalloc(bytes, GFP_KERNEL);
625         else
626                 return (struct hlist_head *)
627                         __get_free_pages(GFP_KERNEL | __GFP_ZERO,
628                                          get_order(bytes));
629 }
630
631 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
632 {
633         if (!hash)
634                 return;
635
636         if (bytes <= PAGE_SIZE)
637                 kfree(hash);
638         else
639                 free_pages((unsigned long) hash, get_order(bytes));
640 }
641
642 static void fib_info_hash_move(struct hlist_head *new_info_hash,
643                                struct hlist_head *new_laddrhash,
644                                unsigned int new_size)
645 {
646         struct hlist_head *old_info_hash, *old_laddrhash;
647         unsigned int old_size = fib_info_hash_size;
648         unsigned int i, bytes;
649
650         spin_lock_bh(&fib_info_lock);
651         old_info_hash = fib_info_hash;
652         old_laddrhash = fib_info_laddrhash;
653         fib_info_hash_size = new_size;
654
655         for (i = 0; i < old_size; i++) {
656                 struct hlist_head *head = &fib_info_hash[i];
657                 struct hlist_node *node, *n;
658                 struct fib_info *fi;
659
660                 hlist_for_each_entry_safe(fi, node, n, head, fib_hash) {
661                         struct hlist_head *dest;
662                         unsigned int new_hash;
663
664                         hlist_del(&fi->fib_hash);
665
666                         new_hash = fib_info_hashfn(fi);
667                         dest = &new_info_hash[new_hash];
668                         hlist_add_head(&fi->fib_hash, dest);
669                 }
670         }
671         fib_info_hash = new_info_hash;
672
673         for (i = 0; i < old_size; i++) {
674                 struct hlist_head *lhead = &fib_info_laddrhash[i];
675                 struct hlist_node *node, *n;
676                 struct fib_info *fi;
677
678                 hlist_for_each_entry_safe(fi, node, n, lhead, fib_lhash) {
679                         struct hlist_head *ldest;
680                         unsigned int new_hash;
681
682                         hlist_del(&fi->fib_lhash);
683
684                         new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
685                         ldest = &new_laddrhash[new_hash];
686                         hlist_add_head(&fi->fib_lhash, ldest);
687                 }
688         }
689         fib_info_laddrhash = new_laddrhash;
690
691         spin_unlock_bh(&fib_info_lock);
692
693         bytes = old_size * sizeof(struct hlist_head *);
694         fib_info_hash_free(old_info_hash, bytes);
695         fib_info_hash_free(old_laddrhash, bytes);
696 }
697
698 struct fib_info *fib_create_info(struct fib_config *cfg)
699 {
700         int err;
701         struct fib_info *fi = NULL;
702         struct fib_info *ofi;
703         int nhs = 1;
704         struct net *net = cfg->fc_nlinfo.nl_net;
705
706         if (cfg->fc_type > RTN_MAX)
707                 goto err_inval;
708
709         /* Fast check to catch the most weird cases */
710         if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
711                 goto err_inval;
712
713 #ifdef CONFIG_IP_ROUTE_MULTIPATH
714         if (cfg->fc_mp) {
715                 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
716                 if (nhs == 0)
717                         goto err_inval;
718         }
719 #endif
720
721         err = -ENOBUFS;
722         if (fib_info_cnt >= fib_info_hash_size) {
723                 unsigned int new_size = fib_info_hash_size << 1;
724                 struct hlist_head *new_info_hash;
725                 struct hlist_head *new_laddrhash;
726                 unsigned int bytes;
727
728                 if (!new_size)
729                         new_size = 1;
730                 bytes = new_size * sizeof(struct hlist_head *);
731                 new_info_hash = fib_info_hash_alloc(bytes);
732                 new_laddrhash = fib_info_hash_alloc(bytes);
733                 if (!new_info_hash || !new_laddrhash) {
734                         fib_info_hash_free(new_info_hash, bytes);
735                         fib_info_hash_free(new_laddrhash, bytes);
736                 } else
737                         fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
738
739                 if (!fib_info_hash_size)
740                         goto failure;
741         }
742
743         fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
744         if (fi == NULL)
745                 goto failure;
746         if (cfg->fc_mx) {
747                 fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
748                 if (!fi->fib_metrics)
749                         goto failure;
750         } else
751                 fi->fib_metrics = (u32 *) dst_default_metrics;
752         fib_info_cnt++;
753
754         fi->fib_net = hold_net(net);
755         fi->fib_protocol = cfg->fc_protocol;
756         fi->fib_flags = cfg->fc_flags;
757         fi->fib_priority = cfg->fc_priority;
758         fi->fib_prefsrc = cfg->fc_prefsrc;
759
760         fi->fib_nhs = nhs;
761         change_nexthops(fi) {
762                 nexthop_nh->nh_parent = fi;
763         } endfor_nexthops(fi)
764
765         if (cfg->fc_mx) {
766                 struct nlattr *nla;
767                 int remaining;
768
769                 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
770                         int type = nla_type(nla);
771
772                         if (type) {
773                                 if (type > RTAX_MAX)
774                                         goto err_inval;
775                                 fi->fib_metrics[type - 1] = nla_get_u32(nla);
776                         }
777                 }
778         }
779
780         if (cfg->fc_mp) {
781 #ifdef CONFIG_IP_ROUTE_MULTIPATH
782                 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
783                 if (err != 0)
784                         goto failure;
785                 if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
786                         goto err_inval;
787                 if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
788                         goto err_inval;
789 #ifdef CONFIG_IP_ROUTE_CLASSID
790                 if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
791                         goto err_inval;
792 #endif
793 #else
794                 goto err_inval;
795 #endif
796         } else {
797                 struct fib_nh *nh = fi->fib_nh;
798
799                 nh->nh_oif = cfg->fc_oif;
800                 nh->nh_gw = cfg->fc_gw;
801                 nh->nh_flags = cfg->fc_flags;
802 #ifdef CONFIG_IP_ROUTE_CLASSID
803                 nh->nh_tclassid = cfg->fc_flow;
804 #endif
805 #ifdef CONFIG_IP_ROUTE_MULTIPATH
806                 nh->nh_weight = 1;
807 #endif
808         }
809
810         if (fib_props[cfg->fc_type].error) {
811                 if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
812                         goto err_inval;
813                 goto link_it;
814         } else {
815                 switch (cfg->fc_type) {
816                 case RTN_UNICAST:
817                 case RTN_LOCAL:
818                 case RTN_BROADCAST:
819                 case RTN_ANYCAST:
820                 case RTN_MULTICAST:
821                         break;
822                 default:
823                         goto err_inval;
824                 }
825         }
826
827         if (cfg->fc_scope > RT_SCOPE_HOST)
828                 goto err_inval;
829
830         if (cfg->fc_scope == RT_SCOPE_HOST) {
831                 struct fib_nh *nh = fi->fib_nh;
832
833                 /* Local address is added. */
834                 if (nhs != 1 || nh->nh_gw)
835                         goto err_inval;
836                 nh->nh_scope = RT_SCOPE_NOWHERE;
837                 nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
838                 err = -ENODEV;
839                 if (nh->nh_dev == NULL)
840                         goto failure;
841         } else {
842                 change_nexthops(fi) {
843                         err = fib_check_nh(cfg, fi, nexthop_nh);
844                         if (err != 0)
845                                 goto failure;
846                 } endfor_nexthops(fi)
847         }
848
849         if (fi->fib_prefsrc) {
850                 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
851                     fi->fib_prefsrc != cfg->fc_dst)
852                         if (inet_addr_type(net, fi->fib_prefsrc) != RTN_LOCAL)
853                                 goto err_inval;
854         }
855
856 link_it:
857         ofi = fib_find_info(fi);
858         if (ofi) {
859                 fi->fib_dead = 1;
860                 free_fib_info(fi);
861                 ofi->fib_treeref++;
862                 return ofi;
863         }
864
865         fi->fib_treeref++;
866         atomic_inc(&fi->fib_clntref);
867         spin_lock_bh(&fib_info_lock);
868         hlist_add_head(&fi->fib_hash,
869                        &fib_info_hash[fib_info_hashfn(fi)]);
870         if (fi->fib_prefsrc) {
871                 struct hlist_head *head;
872
873                 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
874                 hlist_add_head(&fi->fib_lhash, head);
875         }
876         change_nexthops(fi) {
877                 struct hlist_head *head;
878                 unsigned int hash;
879
880                 if (!nexthop_nh->nh_dev)
881                         continue;
882                 hash = fib_devindex_hashfn(nexthop_nh->nh_dev->ifindex);
883                 head = &fib_info_devhash[hash];
884                 hlist_add_head(&nexthop_nh->nh_hash, head);
885         } endfor_nexthops(fi)
886         spin_unlock_bh(&fib_info_lock);
887         return fi;
888
889 err_inval:
890         err = -EINVAL;
891
892 failure:
893         if (fi) {
894                 fi->fib_dead = 1;
895                 free_fib_info(fi);
896         }
897
898         return ERR_PTR(err);
899 }
900
901 /* Find appropriate source address to this destination */
902
903 __be32 __fib_res_prefsrc(struct fib_result *res)
904 {
905         return inet_select_addr(FIB_RES_DEV(*res), FIB_RES_GW(*res), res->scope);
906 }
907
908 int fib_dump_info(struct sk_buff *skb, u32 pid, u32 seq, int event,
909                   u32 tb_id, u8 type, u8 scope, __be32 dst, int dst_len, u8 tos,
910                   struct fib_info *fi, unsigned int flags)
911 {
912         struct nlmsghdr *nlh;
913         struct rtmsg *rtm;
914
915         nlh = nlmsg_put(skb, pid, seq, event, sizeof(*rtm), flags);
916         if (nlh == NULL)
917                 return -EMSGSIZE;
918
919         rtm = nlmsg_data(nlh);
920         rtm->rtm_family = AF_INET;
921         rtm->rtm_dst_len = dst_len;
922         rtm->rtm_src_len = 0;
923         rtm->rtm_tos = tos;
924         if (tb_id < 256)
925                 rtm->rtm_table = tb_id;
926         else
927                 rtm->rtm_table = RT_TABLE_COMPAT;
928         NLA_PUT_U32(skb, RTA_TABLE, tb_id);
929         rtm->rtm_type = type;
930         rtm->rtm_flags = fi->fib_flags;
931         rtm->rtm_scope = scope;
932         rtm->rtm_protocol = fi->fib_protocol;
933
934         if (rtm->rtm_dst_len)
935                 NLA_PUT_BE32(skb, RTA_DST, dst);
936
937         if (fi->fib_priority)
938                 NLA_PUT_U32(skb, RTA_PRIORITY, fi->fib_priority);
939
940         if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
941                 goto nla_put_failure;
942
943         if (fi->fib_prefsrc)
944                 NLA_PUT_BE32(skb, RTA_PREFSRC, fi->fib_prefsrc);
945
946         if (fi->fib_nhs == 1) {
947                 if (fi->fib_nh->nh_gw)
948                         NLA_PUT_BE32(skb, RTA_GATEWAY, fi->fib_nh->nh_gw);
949
950                 if (fi->fib_nh->nh_oif)
951                         NLA_PUT_U32(skb, RTA_OIF, fi->fib_nh->nh_oif);
952 #ifdef CONFIG_IP_ROUTE_CLASSID
953                 if (fi->fib_nh[0].nh_tclassid)
954                         NLA_PUT_U32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid);
955 #endif
956         }
957 #ifdef CONFIG_IP_ROUTE_MULTIPATH
958         if (fi->fib_nhs > 1) {
959                 struct rtnexthop *rtnh;
960                 struct nlattr *mp;
961
962                 mp = nla_nest_start(skb, RTA_MULTIPATH);
963                 if (mp == NULL)
964                         goto nla_put_failure;
965
966                 for_nexthops(fi) {
967                         rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
968                         if (rtnh == NULL)
969                                 goto nla_put_failure;
970
971                         rtnh->rtnh_flags = nh->nh_flags & 0xFF;
972                         rtnh->rtnh_hops = nh->nh_weight - 1;
973                         rtnh->rtnh_ifindex = nh->nh_oif;
974
975                         if (nh->nh_gw)
976                                 NLA_PUT_BE32(skb, RTA_GATEWAY, nh->nh_gw);
977 #ifdef CONFIG_IP_ROUTE_CLASSID
978                         if (nh->nh_tclassid)
979                                 NLA_PUT_U32(skb, RTA_FLOW, nh->nh_tclassid);
980 #endif
981                         /* length of rtnetlink header + attributes */
982                         rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *) rtnh;
983                 } endfor_nexthops(fi);
984
985                 nla_nest_end(skb, mp);
986         }
987 #endif
988         return nlmsg_end(skb, nlh);
989
990 nla_put_failure:
991         nlmsg_cancel(skb, nlh);
992         return -EMSGSIZE;
993 }
994
995 /*
996  * Update FIB if:
997  * - local address disappeared -> we must delete all the entries
998  *   referring to it.
999  * - device went down -> we must shutdown all nexthops going via it.
1000  */
1001 int fib_sync_down_addr(struct net *net, __be32 local)
1002 {
1003         int ret = 0;
1004         unsigned int hash = fib_laddr_hashfn(local);
1005         struct hlist_head *head = &fib_info_laddrhash[hash];
1006         struct hlist_node *node;
1007         struct fib_info *fi;
1008
1009         if (fib_info_laddrhash == NULL || local == 0)
1010                 return 0;
1011
1012         hlist_for_each_entry(fi, node, head, fib_lhash) {
1013                 if (!net_eq(fi->fib_net, net))
1014                         continue;
1015                 if (fi->fib_prefsrc == local) {
1016                         fi->fib_flags |= RTNH_F_DEAD;
1017                         ret++;
1018                 }
1019         }
1020         return ret;
1021 }
1022
1023 int fib_sync_down_dev(struct net_device *dev, int force)
1024 {
1025         int ret = 0;
1026         int scope = RT_SCOPE_NOWHERE;
1027         struct fib_info *prev_fi = NULL;
1028         unsigned int hash = fib_devindex_hashfn(dev->ifindex);
1029         struct hlist_head *head = &fib_info_devhash[hash];
1030         struct hlist_node *node;
1031         struct fib_nh *nh;
1032
1033         if (force)
1034                 scope = -1;
1035
1036         hlist_for_each_entry(nh, node, head, nh_hash) {
1037                 struct fib_info *fi = nh->nh_parent;
1038                 int dead;
1039
1040                 BUG_ON(!fi->fib_nhs);
1041                 if (nh->nh_dev != dev || fi == prev_fi)
1042                         continue;
1043                 prev_fi = fi;
1044                 dead = 0;
1045                 change_nexthops(fi) {
1046                         if (nexthop_nh->nh_flags & RTNH_F_DEAD)
1047                                 dead++;
1048                         else if (nexthop_nh->nh_dev == dev &&
1049                                  nexthop_nh->nh_scope != scope) {
1050                                 nexthop_nh->nh_flags |= RTNH_F_DEAD;
1051 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1052                                 spin_lock_bh(&fib_multipath_lock);
1053                                 fi->fib_power -= nexthop_nh->nh_power;
1054                                 nexthop_nh->nh_power = 0;
1055                                 spin_unlock_bh(&fib_multipath_lock);
1056 #endif
1057                                 dead++;
1058                         }
1059 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1060                         if (force > 1 && nexthop_nh->nh_dev == dev) {
1061                                 dead = fi->fib_nhs;
1062                                 break;
1063                         }
1064 #endif
1065                 } endfor_nexthops(fi)
1066                 if (dead == fi->fib_nhs) {
1067                         fi->fib_flags |= RTNH_F_DEAD;
1068                         ret++;
1069                 }
1070         }
1071
1072         return ret;
1073 }
1074
1075 /* Must be invoked inside of an RCU protected region.  */
1076 void fib_select_default(struct fib_result *res)
1077 {
1078         struct fib_info *fi = NULL, *last_resort = NULL;
1079         struct list_head *fa_head = res->fa_head;
1080         struct fib_table *tb = res->table;
1081         int order = -1, last_idx = -1;
1082         struct fib_alias *fa;
1083
1084         list_for_each_entry_rcu(fa, fa_head, fa_list) {
1085                 struct fib_info *next_fi = fa->fa_info;
1086
1087                 if (fa->fa_scope != res->scope ||
1088                     fa->fa_type != RTN_UNICAST)
1089                         continue;
1090
1091                 if (next_fi->fib_priority > res->fi->fib_priority)
1092                         break;
1093                 if (!next_fi->fib_nh[0].nh_gw ||
1094                     next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
1095                         continue;
1096
1097                 fib_alias_accessed(fa);
1098
1099                 if (fi == NULL) {
1100                         if (next_fi != res->fi)
1101                                 break;
1102                 } else if (!fib_detect_death(fi, order, &last_resort,
1103                                              &last_idx, tb->tb_default)) {
1104                         fib_result_assign(res, fi);
1105                         tb->tb_default = order;
1106                         goto out;
1107                 }
1108                 fi = next_fi;
1109                 order++;
1110         }
1111
1112         if (order <= 0 || fi == NULL) {
1113                 tb->tb_default = -1;
1114                 goto out;
1115         }
1116
1117         if (!fib_detect_death(fi, order, &last_resort, &last_idx,
1118                                 tb->tb_default)) {
1119                 fib_result_assign(res, fi);
1120                 tb->tb_default = order;
1121                 goto out;
1122         }
1123
1124         if (last_idx >= 0)
1125                 fib_result_assign(res, last_resort);
1126         tb->tb_default = last_idx;
1127 out:
1128         return;
1129 }
1130
1131 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1132
1133 /*
1134  * Dead device goes up. We wake up dead nexthops.
1135  * It takes sense only on multipath routes.
1136  */
1137 int fib_sync_up(struct net_device *dev)
1138 {
1139         struct fib_info *prev_fi;
1140         unsigned int hash;
1141         struct hlist_head *head;
1142         struct hlist_node *node;
1143         struct fib_nh *nh;
1144         int ret;
1145
1146         if (!(dev->flags & IFF_UP))
1147                 return 0;
1148
1149         prev_fi = NULL;
1150         hash = fib_devindex_hashfn(dev->ifindex);
1151         head = &fib_info_devhash[hash];
1152         ret = 0;
1153
1154         hlist_for_each_entry(nh, node, head, nh_hash) {
1155                 struct fib_info *fi = nh->nh_parent;
1156                 int alive;
1157
1158                 BUG_ON(!fi->fib_nhs);
1159                 if (nh->nh_dev != dev || fi == prev_fi)
1160                         continue;
1161
1162                 prev_fi = fi;
1163                 alive = 0;
1164                 change_nexthops(fi) {
1165                         if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1166                                 alive++;
1167                                 continue;
1168                         }
1169                         if (nexthop_nh->nh_dev == NULL ||
1170                             !(nexthop_nh->nh_dev->flags & IFF_UP))
1171                                 continue;
1172                         if (nexthop_nh->nh_dev != dev ||
1173                             !__in_dev_get_rtnl(dev))
1174                                 continue;
1175                         alive++;
1176                         spin_lock_bh(&fib_multipath_lock);
1177                         nexthop_nh->nh_power = 0;
1178                         nexthop_nh->nh_flags &= ~RTNH_F_DEAD;
1179                         spin_unlock_bh(&fib_multipath_lock);
1180                 } endfor_nexthops(fi)
1181
1182                 if (alive > 0) {
1183                         fi->fib_flags &= ~RTNH_F_DEAD;
1184                         ret++;
1185                 }
1186         }
1187
1188         return ret;
1189 }
1190
1191 /*
1192  * The algorithm is suboptimal, but it provides really
1193  * fair weighted route distribution.
1194  */
1195 void fib_select_multipath(const struct flowi *flp, struct fib_result *res)
1196 {
1197         struct fib_info *fi = res->fi;
1198         int w;
1199
1200         spin_lock_bh(&fib_multipath_lock);
1201         if (fi->fib_power <= 0) {
1202                 int power = 0;
1203                 change_nexthops(fi) {
1204                         if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) {
1205                                 power += nexthop_nh->nh_weight;
1206                                 nexthop_nh->nh_power = nexthop_nh->nh_weight;
1207                         }
1208                 } endfor_nexthops(fi);
1209                 fi->fib_power = power;
1210                 if (power <= 0) {
1211                         spin_unlock_bh(&fib_multipath_lock);
1212                         /* Race condition: route has just become dead. */
1213                         res->nh_sel = 0;
1214                         return;
1215                 }
1216         }
1217
1218
1219         /* w should be random number [0..fi->fib_power-1],
1220          * it is pretty bad approximation.
1221          */
1222
1223         w = jiffies % fi->fib_power;
1224
1225         change_nexthops(fi) {
1226                 if (!(nexthop_nh->nh_flags & RTNH_F_DEAD) &&
1227                     nexthop_nh->nh_power) {
1228                         w -= nexthop_nh->nh_power;
1229                         if (w <= 0) {
1230                                 nexthop_nh->nh_power--;
1231                                 fi->fib_power--;
1232                                 res->nh_sel = nhsel;
1233                                 spin_unlock_bh(&fib_multipath_lock);
1234                                 return;
1235                         }
1236                 }
1237         } endfor_nexthops(fi);
1238
1239         /* Race condition: route has just become dead. */
1240         res->nh_sel = 0;
1241         spin_unlock_bh(&fib_multipath_lock);
1242 }
1243 #endif