aboutsummaryrefslogtreecommitdiffstats
path: root/net/ipv4/fib_hash.c
blob: 72c633b357cf3bd53592ebb88f4ddeae3560868e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		IPv4 FIB: lookup engine and maintenance routines.
 *
 * Version:	$Id: fib_hash.c,v 1.13 2001/10/31 21:55:54 davem Exp $
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */

#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/proc_fs.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/init.h>

#include <net/ip.h>
#include <net/protocol.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/ip_fib.h>

#include "fib_lookup.h"

static kmem_cache_t *fn_hash_kmem __read_mostly;
static kmem_cache_t *fn_alias_kmem __read_mostly;

struct fib_node {
	struct hlist_node	fn_hash;
	struct list_head	fn_alias;
	u32			fn_key;
};

struct fn_zone {
	struct fn_zone		*fz_next;	/* Next not empty zone	*/
	struct hlist_head	*fz_hash;	/* Hash table pointer	*/
	int			fz_nent;	/* Number of entries	*/

	int			fz_divisor;	/* Hash divisor		*/
	u32			fz_hashmask;	/* (fz_divisor - 1)	*/
#define FZ_HASHMASK(fz)		((fz)->fz_hashmask)

	int			fz_order;	/* Zone order		*/
	u32			fz_mask;
#define FZ_MASK(fz)		((fz)->fz_mask)
};

/* NOTE. On fast computers evaluation of fz_hashmask and fz_mask
 * can be cheaper than memory lookup, so that FZ_* macros are used.
 */

struct fn_hash {
	struct fn_zone	*fn_zones[33];
	struct fn_zone	*fn_zone_list;
};

static inline u32 fn_hash(u32 key, struct fn_zone *fz)
{
	u32 h = ntohl(key)>>(32 - fz->fz_order);
	h ^= (h>>20);
	h ^= (h>>10);
	h ^= (h>>5);
	h &= FZ_HASHMASK(fz);
	return h;
}

static inline u32 fz_key(u32 dst, struct fn_zone *fz)
{
	return dst & FZ_MASK(fz);
}

static DEFINE_RWLOCK(fib_hash_lock);
static unsigned int fib_hash_genid;

#define FZ_MAX_DIVISOR ((PAGE_SIZE<<MAX_ORDER) / sizeof(struct hlist_head))

static struct hlist_head *fz_hash_alloc(int divisor)
{
	unsigned long size = divisor * sizeof(struct hlist_head);

	if (size <= PAGE_SIZE) {
		return kmalloc(size, GFP_KERNEL);
	} else {
		return (struct hlist_head *)
			__get_free_pages(GFP_KERNEL, get_order(size));
	}
}

/* The fib hash lock must be held when this is called. */
static inline void fn_rebuild_zone(struct fn_zone *fz,
				   struct hlist_head *old_ht,
				   int old_divisor)
{
	int i;

	for (i = 0; i < old_divisor; i++) {
		struct hlist_node *node, *n;
		struct fib_node *f;

		hlist_for_each_entry_safe(f, node, n, &old_ht[i], fn_hash) {
			struct hlist_head *new_head;

			hlist_del(&f->fn_hash);

			new_head = &fz->fz_hash[fn_hash(f->fn_key, fz)];
			hlist_add_head(&f->fn_hash, new_head);
		}
	}
}

static void fz_hash_free(struct hlist_head *hash, int divisor)
{
	unsigned long size = divisor * sizeof(struct hlist_head);

	if (size <= PAGE_SIZE)
		kfree(hash);
	else
		free_pages((unsigned long)hash, get_order(size));
}

static void fn_rehash_zone(struct fn_zone *fz)
{
	struct hlist_head *ht, *old_ht;
	int old_divisor, new_divisor;
	u32 new_hashmask;
		
	old_divisor = fz->fz_divisor;

	switch (old_divisor) {
	case 16:
		new_divisor = 256;
		break;
	case 256:
		new_divisor = 1024;
		break;
	default:
		if ((old_divisor << 1) > FZ_MAX_DIVISOR) {
			printk(KERN_CRIT "route.c: bad divisor %d!\n", old_divisor);
			return;
		}
		new_divisor = (old_divisor << 1);
		break;
	}

	new_hashmask = (new_divisor - 1);

#if RT_CACHE_DEBUG >= 2
	printk("fn_rehash_zone: hash for zone %d grows from %d\n", fz->fz_order, old_divisor);
#endif

	ht = fz_hash_alloc(new_divisor);

	if (ht)	{
		memset(ht, 0, new_divisor * sizeof(struct hlist_head));

		write_lock_bh(&fib_hash_lock);
		old_ht = fz->fz_hash;
		fz->fz_hash = ht;
		fz->fz_hashmask = new_hashmask;
		fz->fz_divisor = new_divisor;
		fn_rebuild_zone(fz, old_ht, old_divisor);
		fib_hash_genid++;
		write_unlock_bh(&fib_hash_lock);

		fz_hash_free(old_ht, old_divisor);
	}
}

static inline void fn_free_node(struct fib_node * f)
{
	kmem_cache_free(fn_hash_kmem, f);
}

static inline void fn_free_alias(struct fib_alias *fa)
{
	fib_release_info(fa->fa_info);
	kmem_cache_free(fn_alias_kmem, fa);
}

static struct fn_zone *
fn_new_zone(struct fn_hash *table, int z)
{
	int i;
	struct fn_zone *fz = kzalloc(sizeof(struct fn_zone), GFP_KERNEL);
	if (!fz)
		return NULL;

	if (z) {
		fz->fz_divisor = 16;
	} else {
		fz->fz_divisor = 1;
	}
	fz->fz_hashmask = (fz->fz_divisor - 1);
	fz->fz_hash = fz_hash_alloc(fz->fz_divisor);
	if (!fz->fz_hash) {
		kfree(fz);
		return NULL;
	}
	memset(fz->fz_hash, 0, fz->fz_divisor * sizeof(struct hlist_head *));
	fz->fz_order = z;
	fz->fz_mask = inet_make_mask(z);

	/* Find the first not empty zone with more specific mask */
	for (i=z+1; i<=32; i++)
		if (table->fn_zones[i])
			break;
	write_lock_bh(&fib_hash_lock);
	if (i>32) {
		/* No more specific masks, we are the first. */
		fz->fz_next = table->fn_zone_list;
		table->fn_zone_list = fz;
	} else {
		fz->fz_next = table->fn_zones[i]->fz_next;
		table->fn_zones[i]->fz_next = fz;
	}
	table->fn_zones[z] = fz;
	fib_hash_genid++;
	write_unlock_bh(&fib_hash_lock);
	return fz;
}

static int
fn_hash_lookup(struct fib_table *tb, const struct flowi *flp, struct fib_result *res)
{
	int err;
	struct fn_zone *fz;
	struct fn_hash *t = (struct fn_hash*)tb->tb_data;

	read_lock(&fib_hash_lock);
	for (fz = t->fn_zone_list; fz; fz = fz->fz_next) {
		struct hlist_head *head;
		struct hlist_node *node;
		struct fib_node *f;
		u32 k = fz_key(flp->fl4_dst, fz);

		head = &fz->fz_hash[fn_hash(k, fz)];
		hlist_for_each_entry(f, node, head, fn_hash) {
			if (f->fn_key != k)
				continue;

			err = fib_semantic_match(&f->fn_alias,
						 flp, res,
						 f->fn_key, fz->fz_mask,
						 fz->fz_order);
			if (err <= 0)
				goto out;
		}
	}
	err = 1;
out:
	read_unlock(&fib_hash_lock);
	return err;
}

static int fn_hash_last_dflt=-1;

static void
fn_hash_select_default(struct fib_table *tb, const struct flowi *flp, struct fib_result *res)
{
	int order, last_idx;
	struct hlist_node *node;
	struct fib_node *f;
	struct fib_info *fi = NULL;
	struct fib_info *last_resort;
	struct fn_hash *t = (struct fn_hash*)tb->tb_data;
	struct fn_zone *fz = t->fn_zones[0];

	if (fz == NULL)
		return;

	last_idx = -1;
	last_resort = NULL;
	order = -1;

	read_lock(&fib_hash_lock);
	hlist_for_each_entry(f, node, &fz->fz_hash[0], fn_hash) {
		struct fib_alias *fa;

		list_for_each_entry(fa, &f->fn_alias, fa_list) {
			struct fib_info *next_fi = fa->fa_info;

			if (fa->fa_scope != res->scope ||
			    fa->fa_type != RTN_UNICAST)
				continue;

			if (next_fi->fib_priority > res->fi->fib_priority)
				break;
			if (!next_fi->fib_nh[0].nh_gw ||
			    next_fi->fib_nh[0].nh_scope != RT_SCOPE_LINK)
				continue;
			fa->fa_state |= FA_S_ACCESSED;

			if (fi == NULL) {
				if (next_fi != res->fi)
					break;
			} else if (!fib_detect_death(fi, order, &last_resort,
						     &last_idx, &fn_hash_last_dflt)) {
				if (res->fi)
					fib_info_put(res->fi);
				res->fi = fi;
				atomic_inc(&fi->fib_clntref);
				fn_hash_last_dflt = order;
				goto out;
			}
			fi = next_fi;
			order++;
		}
	}

	if (order <= 0 || fi == NULL) {
		fn_hash_last_dflt = -1;
		goto out;
	}

	if (!fib_detect_death(fi, order, &last_resort, &last_idx, &fn_hash_last_dflt)) {
		if (res->fi)
			fib_info_put(res->fi);
		res->fi = fi;
		atomic_inc(&fi->fib_clntref);
		fn_hash_last_dflt = order;
		goto out;
	}

	if (last_idx >= 0) {
		if (res->fi)
			fib_info_put(res->fi);
		res->fi = last_resort;
		if (last_resort)
			atomic_inc(&last_resort->fib_clntref);
	}
	fn_hash_last_dflt = last_idx;
out:
	read_unlock(&fib_hash_lock);
}

/* Insert node F to FZ. */
static inline void fib_insert_node(struct fn_zone *fz, struct fib_node *f)
{
	struct hlist_head *head = &fz->fz_hash[fn_hash(f->fn_key, fz)];

	hlist_add_head(&f->fn_hash, head);
}

/* Return the node in FZ matching KEY. */
static struct fib_node *fib_find_node(struct fn_zone *fz, u32 key)
{
	struct hlist_head *head = &fz->fz_hash[fn_hash(key, fz)];
	struct hlist_node *node;
	struct fib_node *f;

	hlist_for_each_entry(f, node, head, fn_hash) {
		if (f->fn_key == key)
			return f;
	}

	return NULL;
}

static int
fn_hash_insert(struct fib_table *tb, struct rtmsg *r, struct kern_rta *rta,
	       struct nlmsghdr *n, struct netlink_skb_parms *req)
{
	struct fn_hash *table = (struct fn_hash *) tb->tb_data;
	struct fib_node *new_f, *f;
	struct fib_alias *fa, *new_fa;
	struct fn_zone *fz;
	struct fib_info *fi;
	int z = r->rtm_dst_len;
	int type = r->rtm_type;
	u8 tos = r->rtm_tos;
	u32 key;
	int err;

	if (z > 32)
		return -EINVAL;
	fz = table->fn_zones[z];
	if (!fz && !(fz = fn_new_zone(table, z)))
		return -ENOBUFS;

	key = 0;
	if (rta->rta_dst) {
		u32 dst;
		memcpy(&dst, rta->rta_dst, 4);
		if (dst & ~FZ_MASK(fz))
			return -EINVAL;
		key = fz_key(dst, fz);
	}

	if  ((fi = fib_create_info(r, rta, n, &err)) == NULL)
		return err;

	if (fz->fz_nent > (fz->fz_divisor<<1) &&
	    fz->fz_divisor < FZ_MAX_DIVISOR &&
	    (z==32 || (1<<z) > fz->fz_divisor))
		fn_rehash_zone(fz);

	f = fib_find_node(fz, key);

	if (!f)
		fa = NULL;
	else
		fa = fib_find_alias(&f->fn_alias, tos, fi->fib_priority);

	/* Now fa, if non-NULL, points to the first fib alias
	 * with the same keys [prefix,tos,priority], if such key already
	 * exists or to the node before which we will insert new one.
	 *
	 * If fa is NULL, we will need to allocate a new one and
	 * insert to the head of f.
	 *
	 * If f is NULL, no fib node matched the destination key
	 * and we need to allocate a new one of those as well.
	 */

	if (fa && fa->fa_tos == tos &&
	    fa->fa_info->fib_priority == fi->fib_priority) {
		struct fib_alias *fa_orig;

		err = -EEXIST;
		if (n->nlmsg_flags & NLM_F_EXCL)
			goto out;

		if (n->nlmsg_flags & NLM_F_REPLACE) {
			struct fib_info *fi_drop;
			u8 state;

			write_lock_bh(&fib_hash_lock);
			fi_drop = fa->fa_info;
			fa->fa_info = fi;
			fa->fa_type = type;
			fa->fa_scope = r->rtm_scope;
			state = fa->fa_state;
			fa->fa_state &= ~FA_S_ACCESSED;
			fib_hash_genid++;
			write_unlock_bh(&fib_hash_lock);

			fib_release_info(fi_drop);
			if (state & FA_S_ACCESSED)
				rt_cache_flush(-1);
			return 0;
		}

		/* Error if we find a perfect match which
		 * uses the same scope, type, and nexthop
		 * information.
		 */
		fa_orig = fa;
		fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
		list_for_each_entry_continue(fa, &f->fn_alias, fa_list) {
			if (fa->fa_tos != tos)
				break;
			if (fa->fa_info->fib_priority != fi->fib_priority)
				break;
			if (fa->fa_type == type &&
			    fa->fa_scope == r->rtm_scope &&
			    fa->fa_info == fi)
				goto out;
		}
		if (!(n->nlmsg_flags & NLM_F_APPEND))
			fa = fa_orig;
	}

	err = -ENOENT;
	if (!(n->nlmsg_flags&NLM_F_CREATE))
		goto out;

	err = -ENOBUFS;
	new_fa = kmem_cache_alloc(fn_alias_kmem, SLAB_KERNEL);
	if (new_fa == NULL)
		goto out;

	new_f = NULL;
	if (!f) {
		new_f = kmem_cache_alloc(fn_hash_kmem, SLAB_KERNEL);
		if (new_f == NULL)
			goto out_free_new_fa;

		INIT_HLIST_NODE(&new_f->fn_hash);
		INIT_LIST_HEAD(&new_f->fn_alias);
		new_f->fn_key = key;
		f = new_f;
	}

	new_fa->fa_info = fi;
	new_fa->fa_tos = tos;
	new_fa->fa_type = type;
	new_fa->fa_scope = r->rtm_scope;
	new_fa->fa_state = 0;

	/*
	 * Insert new entry to the list.
	 */

	write_lock_bh(&fib_hash_lock);
	if (new_f)
		fib_insert_node(fz, new_f);
	list_add_tail(&new_fa->fa_list,
		 (fa ? &fa->fa_list : &f->fn_alias));
	fib_hash_genid++;
	write_unlock_bh(&fib_hash_lock);

	if (new_f)
		fz->fz_nent++;
	rt_cache_flush(-1);

	rtmsg_fib(RTM_NEWROUTE, key, new_fa, z, tb->tb_id, n, req);
	return 0;

out_free_new_fa:
	kmem_cache_free(fn_alias_kmem, new_fa);
out:
	fib_release_info(fi);
	return err;
}


static int
fn_hash_delete(struct fib_table *tb, struct rtmsg *r, struct kern_rta *rta,
	       struct nlmsghdr *n, struct netlink_skb_parms *req)
{
	struct fn_hash *table = (struct fn_hash*)tb->tb_data;
	struct fib_node *f;
	struct fib_alias *fa, *fa_to_delete;
	int z = r->rtm_dst_len;
	struct fn_zone *fz;
	u32 key;
	u8 tos = r->rtm_tos;

	if (z > 32)
		return -EINVAL;
	if ((fz  = table->fn_zones[z]) == NULL)
		return -ESRCH;

	key = 0;
	if (rta->rta_dst) {
		u32 dst;
		memcpy(&dst, rta->rta_dst, 4);
		if (dst & ~FZ_MASK(fz))
			return -EINVAL;
		key = fz_key(dst, fz);
	}

	f = fib_find_node(fz, key);

	if (!f)
		fa = NULL;
	else
		fa = fib_find_alias(&f->fn_alias, tos, 0);
	if (!fa)
		return -ESRCH;

	fa_to_delete = NULL;
	fa = list_entry(fa->fa_list.prev, struct fib_alias, fa_list);
	list_for_each_entry_continue(fa, &f->fn_alias, fa_list) {
		struct fib_info *fi = fa->fa_info;

		if (fa->fa_tos != tos)
			break;

		if ((!r->rtm_type ||
		     fa->fa_type == r->rtm_type) &&
		    (r->rtm_scope == RT_SCOPE_NOWHERE ||
		     fa->fa_scope == r->rtm_scope) &&
		    (!r->rtm_protocol ||
		     fi->fib_protocol == r->rtm_protocol) &&
		    fib_nh_match(r, n, rta, fi) == 0) {
			fa_to_delete = fa;
			break;
		}
	}

	if (fa_to_delete) {
		int kill_fn;

		fa = fa_to_delete;
		rtmsg_fib(RTM_DELROUTE, key, fa, z, tb->tb_id, n, req);

		kill_fn = 0;
		write_lock_bh(&fib_hash_lock);
		list_del(&fa->fa_list);
		if (list_empty(&f->fn_alias)) {
			hlist_del(&f->fn_hash);
			kill_fn = 1;
		}
		fib_hash_genid++;
		write_unlock_bh(&fib_hash_lock);

		if (fa->fa_state & FA_S_ACCESSED)
			rt_cache_flush(-1);
		fn_free_alias(fa);
		if (kill_fn) {
			fn_free_node(f);
			fz->fz_nent--;
		}

		return 0;
	}
	return -ESRCH;
}

static int fn_flush_list(struct fn_zone *fz, int idx)
{
	struct hlist_head *head = &fz->fz_hash[idx];
	struct hlist_node *node, *n;
	struct fib_node *f;
	int found = 0;

	hlist_for_each_entry_safe(f, node, n, head, fn_hash) {
		struct fib_alias *fa, *fa_node;
		int kill_f;

		kill_f = 0;
		list_for_each_entry_safe(fa, fa_node, &f->fn_alias, fa_list) {
			struct fib_info *fi = fa->fa_info;

			if (fi && (fi->fib_flags&RTNH_F_DEAD)) {
				write_lock_bh(&fib_hash_lock);
				list_del(&fa->fa_list);
				if (list_empty(&f->fn_alias)) {
					hlist_del(&f->fn_hash);
					kill_f = 1;
				}
				fib_hash_genid++;
				write_unlock_bh(&fib_hash_lock);

				fn_free_alias(fa);
				found++;
			}
		}
		if (kill_f) {
			fn_free_node(f);
			fz->fz_nent--;
		}
	}
	return found;
}

static int fn_hash_flush(struct fib_table *tb)
{
	struct fn_hash *table = (struct fn_hash *) tb->tb_data;
	struct fn_zone *fz;
	int found = 0;

	for (fz = table->fn_zone_list; fz; fz = fz->fz_next) {
		int i;

		for (i = fz->fz_divisor - 1; i >= 0; i--)
			found += fn_flush_list(fz, i);
	}
	return found;
}


static inline int
fn_hash_dump_bucket(struct sk_buff *skb, struct netlink_callback *cb,
		     struct fib_table *tb,
		     struct fn_zone *fz,
		     struct hlist_head *head)
{
	struct hlist_node *node;
	struct fib_node *f;
	int i, s_i;

	s_i = cb->args[3];
	i = 0;
	hlist_for_each_entry(f, node, head, fn_hash) {
		struct fib_alias *fa;

		list_for_each_entry(fa, &f->fn_alias, fa_list) {
			if (i < s_i)
				goto next;

			if (fib_dump_info(skb, NETLINK_CB(cb->skb).pid,
					  cb->nlh->nlmsg_seq,
					  RTM_NEWROUTE,
					  tb->tb_id,
					  fa->fa_type,
					  fa->fa_scope,
					  &f->fn_key,
					  fz->fz_order,
					  fa->fa_tos,
					  fa->fa_info,
					  NLM_F_MULTI) < 0) {
				cb->args[3] = i;
				return -1;
			}
		next:
			i++;
		}
	}
	cb->args[3] = i;
	return skb->len;
}

static inline int
fn_hash_dump_zone(struct sk_buff *skb, struct netlink_callback *cb,
		   struct fib_table *tb,
		   struct fn_zone *fz)
{
	int h, s_h;

	s_h = cb->args[2];
	for (h=0; h < fz->fz_divisor; h++) {
		if (h < s_h) continue;
		if (h > s_h)
			memset(&cb->args[3], 0,
			       sizeof(cb->args) - 3*sizeof(cb->args[0]));
		if (fz->fz_hash == NULL ||
		    hlist_empty(&fz->fz_hash[h]))
			continue;
		if (fn_hash_dump_bucket(skb, cb, tb, fz, &fz->fz_hash[h])<0) {
			cb->args[2] = h;
			return -1;
		}
	}
	cb->args[2] = h;
	return skb->len;
}

static int fn_hash_dump(struct fib_table *tb, struct sk_buff *skb, struct netlink_callback *cb)
{
	int m, s_m;
	struct fn_zone *fz;
	struct fn_hash *table = (struct fn_hash*)tb->tb_data;

	s_m = cb->args[1];
	read_lock(&fib_hash_lock);
	for (fz = table->fn_zone_list, m=0; fz; fz = fz->fz_next, m++) {
		if (m < s_m) continue;
		if (m > s_m)
			memset(&cb->args[2], 0,
			       sizeof(cb->args) - 2*sizeof(cb->args[0]));
		if (fn_hash_dump_zone(skb, cb, tb, fz) < 0) {
			cb->args[1] = m;
			read_unlock(&fib_hash_lock);
			return -1;
		}
	}
	read_unlock(&fib_hash_lock);
	cb->args[1] = m;
	return skb->len;
}

#ifdef CONFIG_IP_MULTIPLE_TABLES
struct fib_table * fib_hash_init(int id)
#else
struct fib_table * __init fib_hash_init(int id)
#endif
{
	struct fib_table *tb;

	if (fn_hash_kmem == NULL)
		fn_hash_kmem = kmem_cache_create("ip_fib_hash",
						 sizeof(struct fib_node),
						 0, SLAB_HWCACHE_ALIGN,
						 NULL, NULL);

	if (fn_alias_kmem == NULL)
		fn_alias_kmem = kmem_cache_create("ip_fib_alias",
						  sizeof(struct fib_alias),
						  0, SLAB_HWCACHE_ALIGN,
						  NULL, NULL);

	tb = kmalloc(sizeof(struct fib_table) + sizeof(struct fn_hash),
		     GFP_KERNEL);
	if (tb == NULL)
		return NULL;

	tb->tb_id = id;
	tb->tb_lookup = fn_hash_lookup;
	tb->tb_insert = fn_hash_insert;
	tb->tb_delete = fn_hash_delete;
	tb->tb_flush = fn_hash_flush;
	tb->tb_select_default = fn_hash_select_default;
	tb->tb_dump = fn_hash_dump;
	memset(tb->tb_data, 0, sizeof(struct fn_hash));
	return tb;
}

/* ------------------------------------------------------------------------ */
#ifdef CONFIG_PROC_FS

struct fib_iter_state {
	struct fn_zone	*zone;
	int		bucket;
	struct hlist_head *hash_head;
	struct fib_node *fn;
	struct fib_alias *fa;
	loff_t pos;
	unsigned int genid;
	int valid;
};

static struct fib_alias *fib_get_first(struct seq_file *seq)
{
	struct fib_iter_state *iter = seq->private;
	struct fn_hash *table = (struct fn_hash *) ip_fib_main_table->tb_data;

	iter->bucket    = 0;
	iter->hash_head = NULL;
	iter->fn        = NULL;
	iter->fa        = NULL;
	iter->pos	= 0;
	iter->genid	= fib_hash_genid;
	iter->valid	= 1;

	for (iter->zone = table->fn_zone_list; iter->zone;
	     iter->zone = iter->zone->fz_next) {
		int maxslot;

		if (!iter->zone->fz_nent)
			continue;

		iter->hash_head = iter->zone->fz_hash;
		maxslot = iter->zone->fz_divisor;

		for (iter->bucket = 0; iter->bucket < maxslot;
		     ++iter->bucket, ++iter->hash_head) {
			struct hlist_node *node;
			struct fib_node *fn;

			hlist_for_each_entry(fn,node,iter->hash_head,fn_hash) {
				struct fib_alias *fa;

				list_for_each_entry(fa,&fn->fn_alias,fa_list) {
					iter->fn = fn;
					iter->fa = fa;
					goto out;
				}
			}
		}
	}
out:
	return iter->fa;
}

static struct fib_alias *fib_get_next(struct seq_file *seq)
{
	struct fib_iter_state *iter = seq->private;
	struct fib_node *fn;
	struct fib_alias *fa;

	/* Advance FA, if any. */
	fn = iter->fn;
	fa = iter->fa;
	if (fa) {
		BUG_ON(!fn);
		list_for_each_entry_continue(fa, &fn->fn_alias, fa_list) {
			iter->fa = fa;
			goto out;
		}
	}

	fa = iter->fa = NULL;

	/* Advance FN. */
	if (fn) {
		struct hlist_node *node = &fn->fn_hash;
		hlist_for_each_entry_continue(fn, node, fn_hash) {
			iter->fn = fn;

			list_for_each_entry(fa, &fn->fn_alias, fa_list) {
				iter->fa = fa;
				goto out;
			}
		}
	}

	fn = iter->fn = NULL;

	/* Advance hash chain. */
	if (!iter->zone)
		goto out;

	for (;;) {
		struct hlist_node *node;
		int maxslot;

		maxslot = iter->zone->fz_divisor;

		while (++iter->bucket < maxslot) {
			iter->hash_head++;

			hlist_for_each_entry(fn, node, iter->hash_head, fn_hash) {
				list_for_each_entry(fa, &fn->fn_alias, fa_list) {
					iter->fn = fn;
					iter->fa = fa;
					goto out;
				}
			}
		}

		iter->zone = iter->zone->fz_next;

		if (!iter->zone)
			goto out;
		
		iter->bucket = 0;
		iter->hash_head = iter->zone->fz_hash;

		hlist_for_each_entry(fn, node, iter->hash_head, fn_hash) {
			list_for_each_entry(fa, &fn->fn_alias, fa_list) {
				iter->fn = fn;
				iter->fa = fa;
				goto out;
			}
		}
	}
out:
	iter->pos++;
	return fa;
}

static struct fib_alias *fib_get_idx(struct seq_file *seq, loff_t pos)
{
	struct fib_iter_state *iter = seq->private;
	struct fib_alias *fa;
	
	if (iter->valid && pos >= iter->pos && iter->genid == fib_hash_genid) {
		fa   = iter->fa;
		pos -= iter->pos;
	} else
		fa = fib_get_first(seq);

	if (fa)
		while (pos && (fa = fib_get_next(seq)))
			--pos;
	return pos ? NULL : fa;
}

static void *fib_seq_start(struct seq_file *seq, loff_t *pos)
{
	void *v = NULL;

	read_lock(&fib_hash_lock);
	if (ip_fib_main_table)
		v = *pos ? fib_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
	return v;
}

static void *fib_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	++*pos;
	return v == SEQ_START_TOKEN ? fib_get_first(seq) : fib_get_next(seq);
}

static void fib_seq_stop(struct seq_file *seq, void *v)
{
	read_unlock(&fib_hash_lock);
}

static unsigned fib_flag_trans(int type, u32 mask, struct fib_info *fi)
{
	static const unsigned type2flags[RTN_MAX + 1] = {
		[7] = RTF_REJECT, [8] = RTF_REJECT,
	};
	unsigned flags = type2flags[type];

	if (fi && fi->fib_nh->nh_gw)
		flags |= RTF_GATEWAY;
	if (mask == 0xFFFFFFFF)
		flags |= RTF_HOST;
	flags |= RTF_UP;
	return flags;
}

/* 
 *	This outputs /proc/net/route.
 *
 *	It always works in backward compatibility mode.
 *	The format of the file is not supposed to be changed.
 */
static int fib_seq_show(struct seq_file *seq, void *v)
{
	struct fib_iter_state *iter;
	char bf[128];
	u32 prefix, mask;
	unsigned flags;
	struct fib_node *f;
	struct fib_alias *fa;
	struct fib_info *fi;

	if (v == SEQ_START_TOKEN) {
		seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
			   "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
			   "\tWindow\tIRTT");
		goto out;
	}

	iter	= seq->private;
	f	= iter->fn;
	fa	= iter->fa;
	fi	= fa->fa_info;
	prefix	= f->fn_key;
	mask	= FZ_MASK(iter->zone);
	flags	= fib_flag_trans(fa->fa_type, mask, fi);
	if (fi)
		snprintf(bf, sizeof(bf),
			 "%s\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
			 fi->fib_dev ? fi->fib_dev->name : "*", prefix,
			 fi->fib_nh->nh_gw, flags, 0, 0, fi->fib_priority,
			 mask, (fi->fib_advmss ? fi->fib_advmss + 40 : 0),
			 fi->fib_window,
			 fi->fib_rtt >> 3);
	else
		snprintf(bf, sizeof(bf),
			 "*\t%08X\t%08X\t%04X\t%d\t%u\t%d\t%08X\t%d\t%u\t%u",
			 prefix, 0, flags, 0, 0, 0, mask, 0, 0, 0);
	seq_printf(seq, "%-127s\n", bf);
out:
	return 0;
}

static struct seq_operations fib_seq_ops = {
	.start  = fib_seq_start,
	.next   = fib_seq_next,
	.stop   = fib_seq_stop,
	.show   = fib_seq_show,
};

static int fib_seq_open(struct inode *inode, struct file *file)
{
	struct seq_file *seq;
	int rc = -ENOMEM;
	struct fib_iter_state *s = kzalloc(sizeof(*s), GFP_KERNEL);
       
	if (!s)
		goto out;

	rc = seq_open(file, &fib_seq_ops);
	if (rc)
		goto out_kfree;

	seq	     = file->private_data;
	seq->private = s;
out:
	return rc;
out_kfree:
	kfree(s);
	goto out;
}

static struct file_operations fib_seq_fops = {
	.owner		= THIS_MODULE,
	.open           = fib_seq_open,
	.read           = seq_read,
	.llseek         = seq_lseek,
	.release	= seq_release_private,
};

int __init fib_proc_init(void)
{
	if (!proc_net_fops_create("route", S_IRUGO, &fib_seq_fops))
		return -ENOMEM;
	return 0;
}

void __init fib_proc_exit(void)
{
	proc_net_remove("route");
}
#endif /* CONFIG_PROC_FS */