[NETFILTER]: remove unneeded rcu_dereference() calls
[linux-2.6.git] / net / ipv4 / fib_hash.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 FIB: lookup engine and maintenance routines.
7  *
8  * Version:     $Id: fib_hash.c,v 1.13 2001/10/31 21:55:54 davem Exp $
9  *
10  * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
11  *
12  *              This program is free software; you can redistribute it and/or
13  *              modify it under the terms of the GNU General Public License
14  *              as published by the Free Software Foundation; either version
15  *              2 of the License, or (at your option) any later version.
16  */
17
18 #include <asm/uaccess.h>
19 #include <asm/system.h>
20 #include <linux/bitops.h>
21 #include <linux/types.h>
22 #include <linux/kernel.h>
23 #include <linux/mm.h>
24 #include <linux/string.h>
25 #include <linux/socket.h>
26 #include <linux/sockios.h>
27 #include <linux/errno.h>
28 #include <linux/in.h>
29 #include <linux/inet.h>
30 #include <linux/inetdevice.h>
31 #include <linux/netdevice.h>
32 #include <linux/if_arp.h>
33 #include <linux/proc_fs.h>
34 #include <linux/skbuff.h>
35 #include <linux/netlink.h>
36 #include <linux/init.h>
37
38 #include <net/net_namespace.h>
39 #include <net/ip.h>
40 #include <net/protocol.h>
41 #include <net/route.h>
42 #include <net/tcp.h>
43 #include <net/sock.h>
44 #include <net/ip_fib.h>
45
46 #include "fib_lookup.h"
47
48 static struct kmem_cache *fn_hash_kmem __read_mostly;
49 static struct kmem_cache *fn_alias_kmem __read_mostly;
50
51 struct fib_node {
52         struct hlist_node       fn_hash;
53         struct list_head        fn_alias;
54         __be32                  fn_key;
55 };
56
57 struct fn_zone {
58         struct fn_zone          *fz_next;       /* Next not empty zone  */
59         struct hlist_head       *fz_hash;       /* Hash table pointer   */
60         int                     fz_nent;        /* Number of entries    */
61
62         int                     fz_divisor;     /* Hash divisor         */
63         u32                     fz_hashmask;    /* (fz_divisor - 1)     */
64 #define FZ_HASHMASK(fz)         ((fz)->fz_hashmask)
65
66         int                     fz_order;       /* Zone order           */
67         __be32                  fz_mask;
68 #define FZ_MASK(fz)             ((fz)->fz_mask)
69 };
70
71 /* NOTE. On fast computers evaluation of fz_hashmask and fz_mask
72  * can be cheaper than memory lookup, so that FZ_* macros are used.
73  */
74
75 struct fn_hash {
76         struct fn_zone  *fn_zones[33];
77         struct fn_zone  *fn_zone_list;
78 };
79
80 static inline u32 fn_hash(__be32 key, struct fn_zone *fz)
81 {
82         u32 h = ntohl(key)>>(32 - fz->fz_order);
83         h ^= (h>>20);
84         h ^= (h>>10);
85         h ^= (h>>5);
86         h &= FZ_HASHMASK(fz);
87         return h;
88 }
89
90 static inline __be32 fz_key(__be32 dst, struct fn_zone *fz)
91 {
92         return dst & FZ_MASK(fz);
93 }
94
95 static DEFINE_RWLOCK(fib_hash_lock);
96 static unsigned int fib_hash_genid;
97
98 #define FZ_MAX_DIVISOR ((PAGE_SIZE<<MAX_ORDER) / sizeof(struct hlist_head))
99
100 static struct hlist_head *fz_hash_alloc(int divisor)
101 {
102         unsigned long size = divisor * sizeof(struct hlist_head);
103
104         if (size <= PAGE_SIZE) {
105                 return kmalloc(size, GFP_KERNEL);
106         } else {
107                 return (struct hlist_head *)
108                         __get_free_pages(GFP_KERNEL, get_order(size));
109         }
110 }
111
112 /* The fib hash lock must be held when this is called. */
113 static inline void fn_rebuild_zone(struct fn_zone *fz,
114                                    struct hlist_head *old_ht,
115                                    int old_divisor)
116 {
117         int i;
118
119         for (i = 0; i < old_divisor; i++) {
120                 struct hlist_node *node, *n;
121                 struct fib_node *f;
122
123                 hlist_for_each_entry_safe(f, node, n, &old_ht[i], fn_hash) {
124                         struct hlist_head *new_head;
125
126                         hlist_del(&f->fn_hash);
127
128                         new_head = &fz->fz_hash[fn_hash(f->fn_key, fz)];
129                         hlist_add_head(&f->fn_hash, new_head);
130                 }
131         }
132 }
133
134 static void fz_hash_free(struct hlist_head *hash, int divisor)
135 {
136         unsigned long size = divisor * sizeof(struct hlist_head);
137
138         if (size <= PAGE_SIZE)
139                 kfree(hash);
140         else
141                 free_pages((unsigned long)hash, get_order(size));
142 }
143
144 static void fn_rehash_zone(struct fn_zone *fz)
145 {
146         struct hlist_head *ht, *old_ht;
147         int old_divisor, new_divisor;
148         u32 new_hashmask;
149
150         old_divisor = fz->fz_divisor;
151
152         switch (old_divisor) {
153         case 16:
154                 new_divisor = 256;
155                 break;
156         case 256:
157                 new_divisor = 1024;
158                 break;
159         default:
160                 if ((old_divisor << 1) > FZ_MAX_DIVISOR) {
161                         printk(KERN_CRIT "route.c: bad divisor %d!\n", old_divisor);
162                         return;
163                 }
164                 new_divisor = (old_divisor << 1);
165                 break;
166         }
167
168         new_hashmask = (new_divisor - 1);
169
170 #if RT_CACHE_DEBUG >= 2
171         printk("fn_rehash_zone: hash for zone %d grows from %d\n", fz->fz_order, old_divisor);
172 #endif
173
174         ht = fz_hash_alloc(new_divisor);
175
176         if (ht) {
177                 memset(ht, 0, new_divisor * sizeof(struct hlist_head));
178
179                 write_lock_bh(&fib_hash_lock);
180                 old_ht = fz->fz_hash;
181                 fz->fz_hash = ht;
182                 fz->fz_hashmask = new_hashmask;
183                 fz->fz_divisor = new_divisor;
184                 fn_rebuild_zone(fz, old_ht, old_divisor);
185                 fib_hash_genid++;
186                 write_unlock_bh(&fib_hash_lock);
187
188                 fz_hash_free(old_ht, old_divisor);
189         }
190 }
191
192 static inline void fn_free_node(struct fib_node * f)
193 {
194         kmem_cache_free(fn_hash_kmem, f);
195 }
196
197 static inline void fn_free_alias(struct fib_alias *fa)
198 {
199         fib_release_info(fa->fa_info);
200         kmem_cache_free(fn_alias_kmem, fa);
201 }
202
203 static struct fn_zone *
204 fn_new_zone(struct fn_hash *table, int z)
205 {
206         int i;
207         struct fn_zone *fz = kzalloc(sizeof(struct fn_zone), GFP_KERNEL);
208         if (!fz)
209                 return NULL;
210
211         if (z) {
212                 fz->fz_divisor = 16;
213         } else {
214                 fz->fz_divisor = 1;
215         }
216         fz->fz_hashmask = (fz->fz_divisor - 1);
217         fz->fz_hash = fz_hash_alloc(fz->fz_divisor);
218         if (!fz->fz_hash) {
219                 kfree(fz);
220                 return NULL;
221         }
222         memset(fz->fz_hash, 0, fz->fz_divisor * sizeof(struct hlist_head *));
223         fz->fz_order = z;
224         fz->fz_mask = inet_make_mask(z);
225
226         /* Find the first not empty zone with more specific mask */
227         for (i=z+1; i<=32; i++)
228                 if (table->fn_zones[i])
229                         break;
230         write_lock_bh(&fib_hash_lock);
231         if (i>32) {
232                 /* No more specific masks, we are the first. */
233                 fz->fz_next = table->fn_zone_list;
234                 table->fn_zone_list = fz;
235         } else {
236                 fz->fz_next = table->fn_zones[i]->fz_next;
237                 table->fn_zones[i]->fz_next = fz;
238         }
239         table->fn_zones[z] = fz;
240         fib_hash_genid++;
241         write_unlock_bh(&fib_hash_lock);
242         return fz;
243 }
244
245 static int
246 fn_hash_lookup(struct fib_table *tb, const struct flowi *flp, struct fib_result *res)
247 {
248         int err;
249         struct fn_zone *fz;
250         struct fn_hash *t = (struct fn_hash*)tb->tb_data;
251
252         read_lock(&fib_hash_lock);
253         for (fz = t->fn_zone_list; fz; fz = fz->fz_next) {
254                 struct hlist_head *head;
255                 struct hlist_node *node;
256                 struct fib_node *f;
257                 __be32 k = fz_key(flp->fl4_dst, fz);
258
259                 head = &fz->fz_hash[fn_hash(k, fz)];
260                 hlist_for_each_entry(f, node, head, fn_hash) {
261                         if (f->fn_key != k)
262                                 continue;
263
264                         err = fib_semantic_match(&f->fn_alias,
265                                                  flp, res,
266                                                  f->fn_key, fz->fz_mask,
267                                                  fz->fz_order);
268                         if (err <= 0)
269                                 goto out;
270                 }
271         }
272         err = 1;
273 out:
274         read_unlock(&fib_hash_lock);
275         return err;
276 }
277
278 static int fn_hash_last_dflt=-1;
279
280 static void
281 fn_hash_select_default(struct fib_table *tb, const struct flowi *flp, struct fib_result *res)
282 {
283         int order, last_idx;
284         struct hlist_node *node;
285         struct fib_node *f;
286         struct fib_info *fi = NULL;
287         struct fib_info *last_resort;
288         struct fn_hash *t = (struct fn_hash*)tb->tb_data;
289         struct fn_zone *fz = t->fn_zones[0];
290
291         if (fz == NULL)
292                 return;
293
294         last_idx = -1;
295         last_resort = NULL;
296         order = -1;
297
298         read_lock(&fib_hash_lock);
299         hlist_for_each_entry(f, node, &fz->fz_hash[0], fn_hash) {
300                 struct fib_alias *fa;
301
302                 list_for_each_entry(fa, &f->fn_alias, fa_list) {
303                         struct fib_info *next_fi = fa->fa_info;
304
305                         if (fa->fa_scope != res->scope ||
306                             fa->fa_type != RTN_UNICAST)
307                                 continue;
308
309                         if (next_fi->fib_priority > res->fi->fib_priority)
310                                 break;
311                         if (!next_fi->fib_nh[0].nh_gw ||
312                             next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
313                                 continue;
314                         fa->fa_state |= FA_S_ACCESSED;
315
316                         if (fi == NULL) {
317                                 if (next_fi != res->fi)
318                                         break;
319                         } else if (!fib_detect_death(fi, order, &last_resort,
320                                                      &last_idx, &fn_hash_last_dflt)) {
321                                 if (res->fi)
322                                         fib_info_put(res->fi);
323                                 res->fi = fi;
324                                 atomic_inc(&fi->fib_clntref);
325                                 fn_hash_last_dflt = order;
326                                 goto out;
327                         }
328                         fi = next_fi;
329                         order++;
330                 }
331         }
332
333         if (order <= 0 || fi == NULL) {
334                 fn_hash_last_dflt = -1;
335                 goto out;
336         }
337
338         if (!fib_detect_death(fi, order, &last_resort, &last_idx, &fn_hash_last_dflt)) {
339                 if (res->fi)
340                         fib_info_put(res->fi);
341                 res->fi = fi;
342                 atomic_inc(&fi->fib_clntref);
343                 fn_hash_last_dflt = order;
344                 goto out;
345         }
346
347         if (last_idx >= 0) {
348                 if (res->fi)
349                         fib_info_put(res->fi);
350                 res->fi = last_resort;
351                 if (last_resort)
352                         atomic_inc(&last_resort->fib_clntref);
353         }
354         fn_hash_last_dflt = last_idx;
355 out:
356         read_unlock(&fib_hash_lock);
357 }
358
359 /* Insert node F to FZ. */
360 static inline void fib_insert_node(struct fn_zone *fz, struct fib_node *f)
361 {
362         struct hlist_head *head = &fz->fz_hash[fn_hash(f->fn_key, fz)];
363
364         hlist_add_head(&f->fn_hash, head);
365 }
366
367 /* Return the node in FZ matching KEY. */
368 static struct fib_node *fib_find_node(struct fn_zone *fz, __be32 key)
369 {
370         struct hlist_head *head = &fz->fz_hash[fn_hash(key, fz)];
371         struct hlist_node *node;
372         struct fib_node *f;
373
374         hlist_for_each_entry(f, node, head, fn_hash) {
375                 if (f->fn_key == key)
376                         return f;
377         }
378
379         return NULL;
380 }
381
382 static int fn_hash_insert(struct fib_table *tb, struct fib_config *cfg)
383 {
384         struct fn_hash *table = (struct fn_hash *) tb->tb_data;
385         struct fib_node *new_f, *f;
386         struct fib_alias *fa, *new_fa;
387         struct fn_zone *fz;
388         struct fib_info *fi;
389         u8 tos = cfg->fc_tos;
390         __be32 key;
391         int err;
392
393         if (cfg->fc_dst_len > 32)
394                 return -EINVAL;
395
396         fz = table->fn_zones[cfg->fc_dst_len];
397         if (!fz && !(fz = fn_new_zone(table, cfg->fc_dst_len)))
398                 return -ENOBUFS;
399
400         key = 0;
401         if (cfg->fc_dst) {
402                 if (cfg->fc_dst & ~FZ_MASK(fz))
403                         return -EINVAL;
404                 key = fz_key(cfg->fc_dst, fz);
405         }
406
407         fi = fib_create_info(cfg);
408         if (IS_ERR(fi))
409                 return PTR_ERR(fi);
410
411         if (fz->fz_nent > (fz->fz_divisor<<1) &&
412             fz->fz_divisor < FZ_MAX_DIVISOR &&
413             (cfg->fc_dst_len == 32 ||
414              (1 << cfg->fc_dst_len) > fz->fz_divisor))
415                 fn_rehash_zone(fz);
416
417         f = fib_find_node(fz, key);
418
419         if (!f)
420                 fa = NULL;
421         else
422                 fa = fib_find_alias(&f->fn_alias, tos, fi->fib_priority);
423
424         /* Now fa, if non-NULL, points to the first fib alias
425          * with the same keys [prefix,tos,priority], if such key already
426          * exists or to the node before which we will insert new one.
427          *
428          * If fa is NULL, we will need to allocate a new one and
429          * insert to the head of f.
430          *
431          * If f is NULL, no fib node matched the destination key
432          * and we need to allocate a new one of those as well.
433          */
434
435         if (fa && fa->fa_tos == tos &&
436             fa->fa_info->fib_priority == fi->fib_priority) {
437                 struct fib_alias *fa_orig;
438
439                 err = -EEXIST;
440                 if (cfg->fc_nlflags & NLM_F_EXCL)
441                         goto out;
442
443                 if (cfg->fc_nlflags & NLM_F_REPLACE) {
444                         struct fib_info *fi_drop;
445                         u8 state;
446
447                         write_lock_bh(&fib_hash_lock);
448                         fi_drop = fa->fa_info;
449                         fa->fa_info = fi;
450                         fa->fa_type = cfg->fc_type;
451                         fa->fa_scope = cfg->fc_scope;
452                         state = fa->fa_state;
453                         fa->fa_state &= ~FA_S_ACCESSED;
454                         fib_hash_genid++;
455                         write_unlock_bh(&fib_hash_lock);
456
457                         fib_release_info(fi_drop);
458                         if (state & FA_S_ACCESSED)
459                                 rt_cache_flush(-1);
460                         rtmsg_fib(RTM_NEWROUTE, key, fa, cfg->fc_dst_len, tb->tb_id,
461                                   &cfg->fc_nlinfo, NLM_F_REPLACE);
462                         return 0;
463                 }
464
465                 /* Error if we find a perfect match which
466                  * uses the same scope, type, and nexthop
467                  * information.
468                  */
469                 fa_orig = fa;
470                 fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
471                 list_for_each_entry_continue(fa, &f->fn_alias, fa_list) {
472                         if (fa->fa_tos != tos)
473                                 break;
474                         if (fa->fa_info->fib_priority != fi->fib_priority)
475                                 break;
476                         if (fa->fa_type == cfg->fc_type &&
477                             fa->fa_scope == cfg->fc_scope &&
478                             fa->fa_info == fi)
479                                 goto out;
480                 }
481                 if (!(cfg->fc_nlflags & NLM_F_APPEND))
482                         fa = fa_orig;
483         }
484
485         err = -ENOENT;
486         if (!(cfg->fc_nlflags & NLM_F_CREATE))
487                 goto out;
488
489         err = -ENOBUFS;
490         new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
491         if (new_fa == NULL)
492                 goto out;
493
494         new_f = NULL;
495         if (!f) {
496                 new_f = kmem_cache_alloc(fn_hash_kmem, GFP_KERNEL);
497                 if (new_f == NULL)
498                         goto out_free_new_fa;
499
500                 INIT_HLIST_NODE(&new_f->fn_hash);
501                 INIT_LIST_HEAD(&new_f->fn_alias);
502                 new_f->fn_key = key;
503                 f = new_f;
504         }
505
506         new_fa->fa_info = fi;
507         new_fa->fa_tos = tos;
508         new_fa->fa_type = cfg->fc_type;
509         new_fa->fa_scope = cfg->fc_scope;
510         new_fa->fa_state = 0;
511
512         /*
513          * Insert new entry to the list.
514          */
515
516         write_lock_bh(&fib_hash_lock);
517         if (new_f)
518                 fib_insert_node(fz, new_f);
519         list_add_tail(&new_fa->fa_list,
520                  (fa ? &fa->fa_list : &f->fn_alias));
521         fib_hash_genid++;
522         write_unlock_bh(&fib_hash_lock);
523
524         if (new_f)
525                 fz->fz_nent++;
526         rt_cache_flush(-1);
527
528         rtmsg_fib(RTM_NEWROUTE, key, new_fa, cfg->fc_dst_len, tb->tb_id,
529                   &cfg->fc_nlinfo, 0);
530         return 0;
531
532 out_free_new_fa:
533         kmem_cache_free(fn_alias_kmem, new_fa);
534 out:
535         fib_release_info(fi);
536         return err;
537 }
538
539
540 static int fn_hash_delete(struct fib_table *tb, struct fib_config *cfg)
541 {
542         struct fn_hash *table = (struct fn_hash*)tb->tb_data;
543         struct fib_node *f;
544         struct fib_alias *fa, *fa_to_delete;
545         struct fn_zone *fz;
546         __be32 key;
547
548         if (cfg->fc_dst_len > 32)
549                 return -EINVAL;
550
551         if ((fz  = table->fn_zones[cfg->fc_dst_len]) == NULL)
552                 return -ESRCH;
553
554         key = 0;
555         if (cfg->fc_dst) {
556                 if (cfg->fc_dst & ~FZ_MASK(fz))
557                         return -EINVAL;
558                 key = fz_key(cfg->fc_dst, fz);
559         }
560
561         f = fib_find_node(fz, key);
562
563         if (!f)
564                 fa = NULL;
565         else
566                 fa = fib_find_alias(&f->fn_alias, cfg->fc_tos, 0);
567         if (!fa)
568                 return -ESRCH;
569
570         fa_to_delete = NULL;
571         fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
572         list_for_each_entry_continue(fa, &f->fn_alias, fa_list) {
573                 struct fib_info *fi = fa->fa_info;
574
575                 if (fa->fa_tos != cfg->fc_tos)
576                         break;
577
578                 if ((!cfg->fc_type ||
579                      fa->fa_type == cfg->fc_type) &&
580                     (cfg->fc_scope == RT_SCOPE_NOWHERE ||
581                      fa->fa_scope == cfg->fc_scope) &&
582                     (!cfg->fc_protocol ||
583                      fi->fib_protocol == cfg->fc_protocol) &&
584                     fib_nh_match(cfg, fi) == 0) {
585                         fa_to_delete = fa;
586                         break;
587                 }
588         }
589
590         if (fa_to_delete) {
591                 int kill_fn;
592
593                 fa = fa_to_delete;
594                 rtmsg_fib(RTM_DELROUTE, key, fa, cfg->fc_dst_len,
595                           tb->tb_id, &cfg->fc_nlinfo, 0);
596
597                 kill_fn = 0;
598                 write_lock_bh(&fib_hash_lock);
599                 list_del(&fa->fa_list);
600                 if (list_empty(&f->fn_alias)) {
601                         hlist_del(&f->fn_hash);
602                         kill_fn = 1;
603                 }
604                 fib_hash_genid++;
605                 write_unlock_bh(&fib_hash_lock);
606
607                 if (fa->fa_state & FA_S_ACCESSED)
608                         rt_cache_flush(-1);
609                 fn_free_alias(fa);
610                 if (kill_fn) {
611                         fn_free_node(f);
612                         fz->fz_nent--;
613                 }
614
615                 return 0;
616         }
617         return -ESRCH;
618 }
619
620 static int fn_flush_list(struct fn_zone *fz, int idx)
621 {
622         struct hlist_head *head = &fz->fz_hash[idx];
623         struct hlist_node *node, *n;
624         struct fib_node *f;
625         int found = 0;
626
627         hlist_for_each_entry_safe(f, node, n, head, fn_hash) {
628                 struct fib_alias *fa, *fa_node;
629                 int kill_f;
630
631                 kill_f = 0;
632                 list_for_each_entry_safe(fa, fa_node, &f->fn_alias, fa_list) {
633                         struct fib_info *fi = fa->fa_info;
634
635                         if (fi && (fi->fib_flags&RTNH_F_DEAD)) {
636                                 write_lock_bh(&fib_hash_lock);
637                                 list_del(&fa->fa_list);
638                                 if (list_empty(&f->fn_alias)) {
639                                         hlist_del(&f->fn_hash);
640                                         kill_f = 1;
641                                 }
642                                 fib_hash_genid++;
643                                 write_unlock_bh(&fib_hash_lock);
644
645                                 fn_free_alias(fa);
646                                 found++;
647                         }
648                 }
649                 if (kill_f) {
650                         fn_free_node(f);
651                         fz->fz_nent--;
652                 }
653         }
654         return found;
655 }
656
657 static int fn_hash_flush(struct fib_table *tb)
658 {
659         struct fn_hash *table = (struct fn_hash *) tb->tb_data;
660         struct fn_zone *fz;
661         int found = 0;
662
663         for (fz = table->fn_zone_list; fz; fz = fz->fz_next) {
664                 int i;
665
666                 for (i = fz->fz_divisor - 1; i >= 0; i--)
667                         found += fn_flush_list(fz, i);
668         }
669         return found;
670 }
671
672
673 static inline int
674 fn_hash_dump_bucket(struct sk_buff *skb, struct netlink_callback *cb,
675                      struct fib_table *tb,
676                      struct fn_zone *fz,
677                      struct hlist_head *head)
678 {
679         struct hlist_node *node;
680         struct fib_node *f;
681         int i, s_i;
682
683         s_i = cb->args[4];
684         i = 0;
685         hlist_for_each_entry(f, node, head, fn_hash) {
686                 struct fib_alias *fa;
687
688                 list_for_each_entry(fa, &f->fn_alias, fa_list) {
689                         if (i < s_i)
690                                 goto next;
691
692                         if (fib_dump_info(skb, NETLINK_CB(cb->skb).pid,
693                                           cb->nlh->nlmsg_seq,
694                                           RTM_NEWROUTE,
695                                           tb->tb_id,
696                                           fa->fa_type,
697                                           fa->fa_scope,
698                                           f->fn_key,
699                                           fz->fz_order,
700                                           fa->fa_tos,
701                                           fa->fa_info,
702                                           NLM_F_MULTI) < 0) {
703                                 cb->args[4] = i;
704                                 return -1;
705                         }
706                 next:
707                         i++;
708                 }
709         }
710         cb->args[4] = i;
711         return skb->len;
712 }
713
714 static inline int
715 fn_hash_dump_zone(struct sk_buff *skb, struct netlink_callback *cb,
716                    struct fib_table *tb,
717                    struct fn_zone *fz)
718 {
719         int h, s_h;
720
721         s_h = cb->args[3];
722         for (h=0; h < fz->fz_divisor; h++) {
723                 if (h < s_h) continue;
724                 if (h > s_h)
725                         memset(&cb->args[4], 0,
726                                sizeof(cb->args) - 4*sizeof(cb->args[0]));
727                 if (fz->fz_hash == NULL ||
728                     hlist_empty(&fz->fz_hash[h]))
729                         continue;
730                 if (fn_hash_dump_bucket(skb, cb, tb, fz, &fz->fz_hash[h])<0) {
731                         cb->args[3] = h;
732                         return -1;
733                 }
734         }
735         cb->args[3] = h;
736         return skb->len;
737 }
738
739 static int fn_hash_dump(struct fib_table *tb, struct sk_buff *skb, struct netlink_callback *cb)
740 {
741         int m, s_m;
742         struct fn_zone *fz;
743         struct fn_hash *table = (struct fn_hash*)tb->tb_data;
744
745         s_m = cb->args[2];
746         read_lock(&fib_hash_lock);
747         for (fz = table->fn_zone_list, m=0; fz; fz = fz->fz_next, m++) {
748                 if (m < s_m) continue;
749                 if (m > s_m)
750                         memset(&cb->args[3], 0,
751                                sizeof(cb->args) - 3*sizeof(cb->args[0]));
752                 if (fn_hash_dump_zone(skb, cb, tb, fz) < 0) {
753                         cb->args[2] = m;
754                         read_unlock(&fib_hash_lock);
755                         return -1;
756                 }
757         }
758         read_unlock(&fib_hash_lock);
759         cb->args[2] = m;
760         return skb->len;
761 }
762
763 #ifdef CONFIG_IP_MULTIPLE_TABLES
764 struct fib_table * fib_hash_init(u32 id)
765 #else
766 struct fib_table * __init fib_hash_init(u32 id)
767 #endif
768 {
769         struct fib_table *tb;
770
771         if (fn_hash_kmem == NULL)
772                 fn_hash_kmem = kmem_cache_create("ip_fib_hash",
773                                                  sizeof(struct fib_node),
774                                                  0, SLAB_HWCACHE_ALIGN,
775                                                  NULL);
776
777         if (fn_alias_kmem == NULL)
778                 fn_alias_kmem = kmem_cache_create("ip_fib_alias",
779                                                   sizeof(struct fib_alias),
780                                                   0, SLAB_HWCACHE_ALIGN,
781                                                   NULL);
782
783         tb = kmalloc(sizeof(struct fib_table) + sizeof(struct fn_hash),
784                      GFP_KERNEL);
785         if (tb == NULL)
786                 return NULL;
787
788         tb->tb_id = id;
789         tb->tb_lookup = fn_hash_lookup;
790         tb->tb_insert = fn_hash_insert;
791         tb->tb_delete = fn_hash_delete;
792         tb->tb_flush = fn_hash_flush;
793         tb->tb_select_default = fn_hash_select_default;
794         tb->tb_dump = fn_hash_dump;
795         memset(tb->tb_data, 0, sizeof(struct fn_hash));
796         return tb;
797 }
798
799 /* ------------------------------------------------------------------------ */
800 #ifdef CONFIG_PROC_FS
801
802 struct fib_iter_state {
803         struct fn_zone  *zone;
804         int             bucket;
805         struct hlist_head *hash_head;
806         struct fib_node *fn;
807         struct fib_alias *fa;
808         loff_t pos;
809         unsigned int genid;
810         int valid;
811 };
812
813 static struct fib_alias *fib_get_first(struct seq_file *seq)
814 {
815         struct fib_iter_state *iter = seq->private;
816         struct fn_hash *table = (struct fn_hash *) ip_fib_main_table->tb_data;
817
818         iter->bucket    = 0;
819         iter->hash_head = NULL;
820         iter->fn        = NULL;
821         iter->fa        = NULL;
822         iter->pos       = 0;
823         iter->genid     = fib_hash_genid;
824         iter->valid     = 1;
825
826         for (iter->zone = table->fn_zone_list; iter->zone;
827              iter->zone = iter->zone->fz_next) {
828                 int maxslot;
829
830                 if (!iter->zone->fz_nent)
831                         continue;
832
833                 iter->hash_head = iter->zone->fz_hash;
834                 maxslot = iter->zone->fz_divisor;
835
836                 for (iter->bucket = 0; iter->bucket < maxslot;
837                      ++iter->bucket, ++iter->hash_head) {
838                         struct hlist_node *node;
839                         struct fib_node *fn;
840
841                         hlist_for_each_entry(fn,node,iter->hash_head,fn_hash) {
842                                 struct fib_alias *fa;
843
844                                 list_for_each_entry(fa,&fn->fn_alias,fa_list) {
845                                         iter->fn = fn;
846                                         iter->fa = fa;
847                                         goto out;
848                                 }
849                         }
850                 }
851         }
852 out:
853         return iter->fa;
854 }
855
856 static struct fib_alias *fib_get_next(struct seq_file *seq)
857 {
858         struct fib_iter_state *iter = seq->private;
859         struct fib_node *fn;
860         struct fib_alias *fa;
861
862         /* Advance FA, if any. */
863         fn = iter->fn;
864         fa = iter->fa;
865         if (fa) {
866                 BUG_ON(!fn);
867                 list_for_each_entry_continue(fa, &fn->fn_alias, fa_list) {
868                         iter->fa = fa;
869                         goto out;
870                 }
871         }
872
873         fa = iter->fa = NULL;
874
875         /* Advance FN. */
876         if (fn) {
877                 struct hlist_node *node = &fn->fn_hash;
878                 hlist_for_each_entry_continue(fn, node, fn_hash) {
879                         iter->fn = fn;
880
881                         list_for_each_entry(fa, &fn->fn_alias, fa_list) {
882                                 iter->fa = fa;
883                                 goto out;
884                         }
885                 }
886         }
887
888         fn = iter->fn = NULL;
889
890         /* Advance hash chain. */
891         if (!iter->zone)
892                 goto out;
893
894         for (;;) {
895                 struct hlist_node *node;
896                 int maxslot;
897
898                 maxslot = iter->zone->fz_divisor;
899
900                 while (++iter->bucket < maxslot) {
901                         iter->hash_head++;
902
903                         hlist_for_each_entry(fn, node, iter->hash_head, fn_hash) {
904                                 list_for_each_entry(fa, &fn->fn_alias, fa_list) {
905                                         iter->fn = fn;
906                                         iter->fa = fa;
907                                         goto out;
908                                 }
909                         }
910                 }
911
912                 iter->zone = iter->zone->fz_next;
913
914                 if (!iter->zone)
915                         goto out;
916
917                 iter->bucket = 0;
918                 iter->hash_head = iter->zone->fz_hash;
919
920                 hlist_for_each_entry(fn, node, iter->hash_head, fn_hash) {
921                         list_for_each_entry(fa, &fn->fn_alias, fa_list) {
922                                 iter->fn = fn;
923                                 iter->fa = fa;
924                                 goto out;
925                         }
926                 }
927         }
928 out:
929         iter->pos++;
930         return fa;
931 }
932
933 static struct fib_alias *fib_get_idx(struct seq_file *seq, loff_t pos)
934 {
935         struct fib_iter_state *iter = seq->private;
936         struct fib_alias *fa;
937
938         if (iter->valid && pos >= iter->pos && iter->genid == fib_hash_genid) {
939                 fa   = iter->fa;
940                 pos -= iter->pos;
941         } else
942                 fa = fib_get_first(seq);
943
944         if (fa)
945                 while (pos && (fa = fib_get_next(seq)))
946                         --pos;
947         return pos ? NULL : fa;
948 }
949
950 static void *fib_seq_start(struct seq_file *seq, loff_t *pos)
951 {
952         void *v = NULL;
953
954         read_lock(&fib_hash_lock);
955         if (ip_fib_main_table)
956                 v = *pos ? fib_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
957         return v;
958 }
959
960 static void *fib_seq_next(struct seq_file *seq, void *v, loff_t *pos)
961 {
962         ++*pos;
963         return v == SEQ_START_TOKEN ? fib_get_first(seq) : fib_get_next(seq);
964 }
965
966 static void fib_seq_stop(struct seq_file *seq, void *v)
967 {
968         read_unlock(&fib_hash_lock);
969 }
970
971 static unsigned fib_flag_trans(int type, __be32 mask, struct fib_info *fi)
972 {
973         static const unsigned type2flags[RTN_MAX + 1] = {
974                 [7] = RTF_REJECT, [8] = RTF_REJECT,
975         };
976         unsigned flags = type2flags[type];
977
978         if (fi && fi->fib_nh->nh_gw)
979                 flags |= RTF_GATEWAY;
980         if (mask == htonl(0xFFFFFFFF))
981                 flags |= RTF_HOST;
982         flags |= RTF_UP;
983         return flags;
984 }
985
986 /*
987  *      This outputs /proc/net/route.
988  *
989  *      It always works in backward compatibility mode.
990  *      The format of the file is not supposed to be changed.
991  */
992 static int fib_seq_show(struct seq_file *seq, void *v)
993 {
994         struct fib_iter_state *iter;
995         char bf[128];
996         __be32 prefix, mask;
997         unsigned flags;
998         struct fib_node *f;
999         struct fib_alias *fa;
1000         struct fib_info *fi;
1001
1002         if (v == SEQ_START_TOKEN) {
1003                 seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
1004                            "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
1005                            "\tWindow\tIRTT");
1006                 goto out;
1007         }
1008
1009         iter    = seq->private;
1010         f       = iter->fn;
1011         fa      = iter->fa;
1012         fi      = fa->fa_info;
1013         prefix  = f->fn_key;
1014         mask    = FZ_MASK(iter->zone);
1015         flags   = fib_flag_trans(fa->fa_type, mask, fi);
1016         if (fi)
1017                 snprintf(bf, sizeof(bf),
1018                          "%s\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
1019                          fi->fib_dev ? fi->fib_dev->name : "*", prefix,
1020                          fi->fib_nh->nh_gw, flags, 0, 0, fi->fib_priority,
1021                          mask, (fi->fib_advmss ? fi->fib_advmss + 40 : 0),
1022                          fi->fib_window,
1023                          fi->fib_rtt >> 3);
1024         else
1025                 snprintf(bf, sizeof(bf),
1026                          "*\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
1027                          prefix, 0, flags, 0, 0, 0, mask, 0, 0, 0);
1028         seq_printf(seq, "%-127s\n", bf);
1029 out:
1030         return 0;
1031 }
1032
1033 static const struct seq_operations fib_seq_ops = {
1034         .start  = fib_seq_start,
1035         .next   = fib_seq_next,
1036         .stop   = fib_seq_stop,
1037         .show   = fib_seq_show,
1038 };
1039
1040 static int fib_seq_open(struct inode *inode, struct file *file)
1041 {
1042         return seq_open_private(file, &fib_seq_ops,
1043                         sizeof(struct fib_iter_state));
1044 }
1045
1046 static const struct file_operations fib_seq_fops = {
1047         .owner          = THIS_MODULE,
1048         .open           = fib_seq_open,
1049         .read           = seq_read,
1050         .llseek         = seq_lseek,
1051         .release        = seq_release_private,
1052 };
1053
1054 int __init fib_proc_init(void)
1055 {
1056         if (!proc_net_fops_create(&init_net, "route", S_IRUGO, &fib_seq_fops))
1057                 return -ENOMEM;
1058         return 0;
1059 }
1060
1061 void __init fib_proc_exit(void)
1062 {
1063         proc_net_remove(&init_net, "route");
1064 }
1065 #endif /* CONFIG_PROC_FS */