summaryrefslogtreecommitdiffstats
path: root/net/ipv4/fib_frontend.c
blob: f823ca34cb12fd691e7e2ccbdf13fa59cf5bf478 (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
/*
 * 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 Forwarding Information Base: FIB frontend.
 *
 * Version:	$Id: fib_frontend.c,v 1.26 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 <linux/module.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/capability.h>
#include <linux/types.h>
#include <linux/kernel.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_addr.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/list.h>

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

#define FFprint(a...) printk(KERN_DEBUG a)

#ifndef CONFIG_IP_MULTIPLE_TABLES

struct fib_table *ip_fib_local_table;
struct fib_table *ip_fib_main_table;

#define FIB_TABLE_HASHSZ 1
static struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ];

#else

#define FIB_TABLE_HASHSZ 256
static struct hlist_head fib_table_hash[FIB_TABLE_HASHSZ];

struct fib_table *fib_new_table(u32 id)
{
	struct fib_table *tb;
	unsigned int h;

	if (id == 0)
		id = RT_TABLE_MAIN;
	tb = fib_get_table(id);
	if (tb)
		return tb;
	tb = fib_hash_init(id);
	if (!tb)
		return NULL;
	h = id & (FIB_TABLE_HASHSZ - 1);
	hlist_add_head_rcu(&tb->tb_hlist, &fib_table_hash[h]);
	return tb;
}

struct fib_table *fib_get_table(u32 id)
{
	struct fib_table *tb;
	struct hlist_node *node;
	unsigned int h;

	if (id == 0)
		id = RT_TABLE_MAIN;
	h = id & (FIB_TABLE_HASHSZ - 1);
	rcu_read_lock();
	hlist_for_each_entry_rcu(tb, node, &fib_table_hash[h], tb_hlist) {
		if (tb->tb_id == id) {
			rcu_read_unlock();
			return tb;
		}
	}
	rcu_read_unlock();
	return NULL;
}
#endif /* CONFIG_IP_MULTIPLE_TABLES */

static void fib_flush(void)
{
	int flushed = 0;
	struct fib_table *tb;
	struct hlist_node *node;
	unsigned int h;

	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
		hlist_for_each_entry(tb, node, &fib_table_hash[h], tb_hlist)
			flushed += tb->tb_flush(tb);
	}

	if (flushed)
		rt_cache_flush(-1);
}

/*
 *	Find the first device with a given source address.
 */

struct net_device * ip_dev_find(__be32 addr)
{
	struct flowi fl = { .nl_u = { .ip4_u = { .daddr = addr } } };
	struct fib_result res;
	struct net_device *dev = NULL;

#ifdef CONFIG_IP_MULTIPLE_TABLES
	res.r = NULL;
#endif

	if (!ip_fib_local_table ||
	    ip_fib_local_table->tb_lookup(ip_fib_local_table, &fl, &res))
		return NULL;
	if (res.type != RTN_LOCAL)
		goto out;
	dev = FIB_RES_DEV(res);

	if (dev)
		dev_hold(dev);
out:
	fib_res_put(&res);
	return dev;
}

unsigned inet_addr_type(__be32 addr)
{
	struct flowi		fl = { .nl_u = { .ip4_u = { .daddr = addr } } };
	struct fib_result	res;
	unsigned ret = RTN_BROADCAST;

	if (ZERONET(addr) || BADCLASS(addr))
		return RTN_BROADCAST;
	if (MULTICAST(addr))
		return RTN_MULTICAST;

#ifdef CONFIG_IP_MULTIPLE_TABLES
	res.r = NULL;
#endif

	if (ip_fib_local_table) {
		ret = RTN_UNICAST;
		if (!ip_fib_local_table->tb_lookup(ip_fib_local_table,
						   &fl, &res)) {
			ret = res.type;
			fib_res_put(&res);
		}
	}
	return ret;
}

/* Given (packet source, input interface) and optional (dst, oif, tos):
   - (main) check, that source is valid i.e. not broadcast or our local
     address.
   - figure out what "logical" interface this packet arrived
     and calculate "specific destination" address.
   - check, that packet arrived from expected physical interface.
 */

int fib_validate_source(__be32 src, __be32 dst, u8 tos, int oif,
			struct net_device *dev, __be32 *spec_dst, u32 *itag)
{
	struct in_device *in_dev;
	struct flowi fl = { .nl_u = { .ip4_u =
				      { .daddr = src,
					.saddr = dst,
					.tos = tos } },
			    .iif = oif };
	struct fib_result res;
	int no_addr, rpf;
	int ret;

	no_addr = rpf = 0;
	rcu_read_lock();
	in_dev = __in_dev_get_rcu(dev);
	if (in_dev) {
		no_addr = in_dev->ifa_list == NULL;
		rpf = IN_DEV_RPFILTER(in_dev);
	}
	rcu_read_unlock();

	if (in_dev == NULL)
		goto e_inval;

	if (fib_lookup(&fl, &res))
		goto last_resort;
	if (res.type != RTN_UNICAST)
		goto e_inval_res;
	*spec_dst = FIB_RES_PREFSRC(res);
	fib_combine_itag(itag, &res);
#ifdef CONFIG_IP_ROUTE_MULTIPATH
	if (FIB_RES_DEV(res) == dev || res.fi->fib_nhs > 1)
#else
	if (FIB_RES_DEV(res) == dev)
#endif
	{
		ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
		fib_res_put(&res);
		return ret;
	}
	fib_res_put(&res);
	if (no_addr)
		goto last_resort;
	if (rpf)
		goto e_inval;
	fl.oif = dev->ifindex;

	ret = 0;
	if (fib_lookup(&fl, &res) == 0) {
		if (res.type == RTN_UNICAST) {
			*spec_dst = FIB_RES_PREFSRC(res);
			ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST;
		}
		fib_res_put(&res);
	}
	return ret;

last_resort:
	if (rpf)
		goto e_inval;
	*spec_dst = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
	*itag = 0;
	return 0;

e_inval_res:
	fib_res_put(&res);
e_inval:
	return -EINVAL;
}

static inline __be32 sk_extract_addr(struct sockaddr *addr)
{
	return ((struct sockaddr_in *) addr)->sin_addr.s_addr;
}

static int put_rtax(struct nlattr *mx, int len, int type, u32 value)
{
	struct nlattr *nla;

	nla = (struct nlattr *) ((char *) mx + len);
	nla->nla_type = type;
	nla->nla_len = nla_attr_size(4);
	*(u32 *) nla_data(nla) = value;

	return len + nla_total_size(4);
}

static int rtentry_to_fib_config(int cmd, struct rtentry *rt,
				 struct fib_config *cfg)
{
	__be32 addr;
	int plen;

	memset(cfg, 0, sizeof(*cfg));

	if (rt->rt_dst.sa_family != AF_INET)
		return -EAFNOSUPPORT;

	/*
	 * Check mask for validity:
	 * a) it must be contiguous.
	 * b) destination must have all host bits clear.
	 * c) if application forgot to set correct family (AF_INET),
	 *    reject request unless it is absolutely clear i.e.
	 *    both family and mask are zero.
	 */
	plen = 32;
	addr = sk_extract_addr(&rt->rt_dst);
	if (!(rt->rt_flags & RTF_HOST)) {
		__be32 mask = sk_extract_addr(&rt->rt_genmask);

		if (rt->rt_genmask.sa_family != AF_INET) {
			if (mask || rt->rt_genmask.sa_family)
				return -EAFNOSUPPORT;
		}

		if (bad_mask(mask, addr))
			return -EINVAL;

		plen = inet_mask_len(mask);
	}

	cfg->fc_dst_len = plen;
	cfg->fc_dst = addr;

	if (cmd != SIOCDELRT) {
		cfg->fc_nlflags = NLM_F_CREATE;
		cfg->fc_protocol = RTPROT_BOOT;
	}

	if (rt->rt_metric)
		cfg->fc_priority = rt->rt_metric - 1;

	if (rt->rt_flags & RTF_REJECT) {
		cfg->fc_scope = RT_SCOPE_HOST;
		cfg->fc_type = RTN_UNREACHABLE;
		return 0;
	}

	cfg->fc_scope = RT_SCOPE_NOWHERE;
	cfg->fc_type = RTN_UNICAST;

	if (rt->rt_dev) {
		char *colon;
		struct net_device *dev;
		char devname[IFNAMSIZ];

		if (copy_from_user(devname, rt->rt_dev, IFNAMSIZ-1))
			return -EFAULT;

		devname[IFNAMSIZ-1] = 0;
		colon = strchr(devname, ':');
		if (colon)
			*colon = 0;
		dev = __dev_get_by_name(&init_net, devname);
		if (!dev)
			return -ENODEV;
		cfg->fc_oif = dev->ifindex;
		if (colon) {
			struct in_ifaddr *ifa;
			struct in_device *in_dev = __in_dev_get_rtnl(dev);
			if (!in_dev)
				return -ENODEV;
			*colon = ':';
			for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next)
				if (strcmp(ifa->ifa_label, devname) == 0)
					break;
			if (ifa == NULL)
				return -ENODEV;
			cfg->fc_prefsrc = ifa->ifa_local;
		}
	}

	addr = sk_extract_addr(&rt->rt_gateway);
	if (rt->rt_gateway.sa_family == AF_INET && addr) {
		cfg->fc_gw = addr;
		if (rt->rt_flags & RTF_GATEWAY &&
		    inet_addr_type(addr) == RTN_UNICAST)
			cfg->fc_scope = RT_SCOPE_UNIVERSE;
	}

	if (cmd == SIOCDELRT)
		return 0;

	if (rt->rt_flags & RTF_GATEWAY && !cfg->fc_gw)
		return -EINVAL;

	if (cfg->fc_scope == RT_SCOPE_NOWHERE)
		cfg->fc_scope = RT_SCOPE_LINK;

	if (rt->rt_flags & (RTF_MTU | RTF_WINDOW | RTF_IRTT)) {
		struct nlattr *mx;
		int len = 0;

		mx = kzalloc(3 * nla_total_size(4), GFP_KERNEL);
		if (mx == NULL)
			return -ENOMEM;

		if (rt->rt_flags & RTF_MTU)
			len = put_rtax(mx, len, RTAX_ADVMSS, rt->rt_mtu - 40);

		if (rt->rt_flags & RTF_WINDOW)
			len = put_rtax(mx, len, RTAX_WINDOW, rt->rt_window);

		if (rt->rt_flags & RTF_IRTT)
			len = put_rtax(mx, len, RTAX_RTT, rt->rt_irtt << 3);

		cfg->fc_mx = mx;
		cfg->fc_mx_len = len;
	}

	return 0;
}

/*
 *	Handle IP routing ioctl calls. These are used to manipulate the routing tables
 */

int ip_rt_ioctl(unsigned int cmd, void __user *arg)
{
	struct fib_config cfg;
	struct rtentry rt;
	int err;

	switch (cmd) {
	case SIOCADDRT:		/* Add a route */
	case SIOCDELRT:		/* Delete a route */
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		if (copy_from_user(&rt, arg, sizeof(rt)))
			return -EFAULT;

		rtnl_lock();
		err = rtentry_to_fib_config(cmd, &rt, &cfg);
		if (err == 0) {
			struct fib_table *tb;

			if (cmd == SIOCDELRT) {
				tb = fib_get_table(cfg.fc_table);
				if (tb)
					err = tb->tb_delete(tb, &cfg);
				else
					err = -ESRCH;
			} else {
				tb = fib_new_table(cfg.fc_table);
				if (tb)
					err = tb->tb_insert(tb, &cfg);
				else
					err = -ENOBUFS;
			}

			/* allocated by rtentry_to_fib_config() */
			kfree(cfg.fc_mx);
		}
		rtnl_unlock();
		return err;
	}
	return -EINVAL;
}

const struct nla_policy rtm_ipv4_policy[RTA_MAX+1] = {
	[RTA_DST]		= { .type = NLA_U32 },
	[RTA_SRC]		= { .type = NLA_U32 },
	[RTA_IIF]		= { .type = NLA_U32 },
	[RTA_OIF]		= { .type = NLA_U32 },
	[RTA_GATEWAY]		= { .type = NLA_U32 },
	[RTA_PRIORITY]		= { .type = NLA_U32 },
	[RTA_PREFSRC]		= { .type = NLA_U32 },
	[RTA_METRICS]		= { .type = NLA_NESTED },
	[RTA_MULTIPATH]		= { .len = sizeof(struct rtnexthop) },
	[RTA_PROTOINFO]		= { .type = NLA_U32 },
	[RTA_FLOW]		= { .type = NLA_U32 },
};

static int rtm_to_fib_config(struct sk_buff *skb, struct nlmsghdr *nlh,
			     struct fib_config *cfg)
{
	struct nlattr *attr;
	int err, remaining;
	struct rtmsg *rtm;

	err = nlmsg_validate(nlh, sizeof(*rtm), RTA_MAX, rtm_ipv4_policy);
	if (err < 0)
		goto errout;

	memset(cfg, 0, sizeof(*cfg));

	rtm = nlmsg_data(nlh);
	cfg->fc_dst_len = rtm->rtm_dst_len;
	cfg->fc_tos = rtm->rtm_tos;
	cfg->fc_table = rtm->rtm_table;
	cfg->fc_protocol = rtm->rtm_protocol;
	cfg->fc_scope = rtm->rtm_scope;
	cfg->fc_type = rtm->rtm_type;
	cfg->fc_flags = rtm->rtm_flags;
	cfg->fc_nlflags = nlh->nlmsg_flags;

	cfg->fc_nlinfo.pid = NETLINK_CB(skb).pid;
	cfg->fc_nlinfo.nlh = nlh;

	if (cfg->fc_type > RTN_MAX) {
		err = -EINVAL;
		goto errout;
	}

	nlmsg_for_each_attr(attr, nlh, sizeof(struct rtmsg), remaining) {
		switch (nla_type(attr)) {
		case RTA_DST:
			cfg->fc_dst = nla_get_be32(attr);
			break;
		case RTA_OIF:
			cfg->fc_oif = nla_get_u32(attr);
			break;
		case RTA_GATEWAY:
			cfg->fc_gw = nla_get_be32(attr);
			break;
		case RTA_PRIORITY:
			cfg->fc_priority = nla_get_u32(attr);
			break;
		case RTA_PREFSRC:
			cfg->fc_prefsrc = nla_get_be32(attr);
			break;
		case RTA_METRICS:
			cfg->fc_mx = nla_data(attr);
			cfg->fc_mx_len = nla_len(attr);
			break;
		case RTA_MULTIPATH:
			cfg->fc_mp = nla_data(attr);
			cfg->fc_mp_len = nla_len(attr);
			break;
		case RTA_FLOW:
			cfg->fc_flow = nla_get_u32(attr);
			break;
		case RTA_TABLE:
			cfg->fc_table = nla_get_u32(attr);
			break;
		}
	}

	return 0;
errout:
	return err;
}

static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
{
	struct fib_config cfg;
	struct fib_table *tb;
	int err;

	err = rtm_to_fib_config(skb, nlh, &cfg);
	if (err < 0)
		goto errout;

	tb = fib_get_table(cfg.fc_table);
	if (tb == NULL) {
		err = -ESRCH;
		goto errout;
	}

	err = tb->tb_delete(tb, &cfg);
errout:
	return err;
}

static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
{
	struct fib_config cfg;
	struct fib_table *tb;
	int err;

	err = rtm_to_fib_config(skb, nlh, &cfg);
	if (err < 0)
		goto errout;

	tb = fib_new_table(cfg.fc_table);
	if (tb == NULL) {
		err = -ENOBUFS;
		goto errout;
	}

	err = tb->tb_insert(tb, &cfg);
errout:
	return err;
}

static int inet_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
{
	unsigned int h, s_h;
	unsigned int e = 0, s_e;
	struct fib_table *tb;
	struct hlist_node *node;
	int dumped = 0;

	if (nlmsg_len(cb->nlh) >= sizeof(struct rtmsg) &&
	    ((struct rtmsg *) nlmsg_data(cb->nlh))->rtm_flags & RTM_F_CLONED)
		return ip_rt_dump(skb, cb);

	s_h = cb->args[0];
	s_e = cb->args[1];

	for (h = s_h; h < FIB_TABLE_HASHSZ; h++, s_e = 0) {
		e = 0;
		hlist_for_each_entry(tb, node, &fib_table_hash[h], tb_hlist) {
			if (e < s_e)
				goto next;
			if (dumped)
				memset(&cb->args[2], 0, sizeof(cb->args) -
						 2 * sizeof(cb->args[0]));
			if (tb->tb_dump(tb, skb, cb) < 0)
				goto out;
			dumped = 1;
next:
			e++;
		}
	}
out:
	cb->args[1] = e;
	cb->args[0] = h;

	return skb->len;
}

/* Prepare and feed intra-kernel routing request.
   Really, it should be netlink message, but :-( netlink
   can be not configured, so that we feed it directly
   to fib engine. It is legal, because all events occur
   only when netlink is already locked.
 */

static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifaddr *ifa)
{
	struct fib_table *tb;
	struct fib_config cfg = {
		.fc_protocol = RTPROT_KERNEL,
		.fc_type = type,
		.fc_dst = dst,
		.fc_dst_len = dst_len,
		.fc_prefsrc = ifa->ifa_local,
		.fc_oif = ifa->ifa_dev->dev->ifindex,
		.fc_nlflags = NLM_F_CREATE | NLM_F_APPEND,
	};

	if (type == RTN_UNICAST)
		tb = fib_new_table(RT_TABLE_MAIN);
	else
		tb = fib_new_table(RT_TABLE_LOCAL);

	if (tb == NULL)
		return;

	cfg.fc_table = tb->tb_id;

	if (type != RTN_LOCAL)
		cfg.fc_scope = RT_SCOPE_LINK;
	else
		cfg.fc_scope = RT_SCOPE_HOST;

	if (cmd == RTM_NEWROUTE)
		tb->tb_insert(tb, &cfg);
	else
		tb->tb_delete(tb, &cfg);
}

void fib_add_ifaddr(struct in_ifaddr *ifa)
{
	struct in_device *in_dev = ifa->ifa_dev;
	struct net_device *dev = in_dev->dev;
	struct in_ifaddr *prim = ifa;
	__be32 mask = ifa->ifa_mask;
	__be32 addr = ifa->ifa_local;
	__be32 prefix = ifa->ifa_address&mask;

	if (ifa->ifa_flags&IFA_F_SECONDARY) {
		prim = inet_ifa_byprefix(in_dev, prefix, mask);
		if (prim == NULL) {
			printk(KERN_DEBUG "fib_add_ifaddr: bug: prim == NULL\n");
			return;
		}
	}

	fib_magic(RTM_NEWROUTE, RTN_LOCAL, addr, 32, prim);

	if (!(dev->flags&IFF_UP))
		return;

	/* Add broadcast address, if it is explicitly assigned. */
	if (ifa->ifa_broadcast && ifa->ifa_broadcast != htonl(0xFFFFFFFF))
		fib_magic(RTM_NEWROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);

	if (!ZERONET(prefix) && !(ifa->ifa_flags&IFA_F_SECONDARY) &&
	    (prefix != addr || ifa->ifa_prefixlen < 32)) {
		fib_magic(RTM_NEWROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL :
			  RTN_UNICAST, prefix, ifa->ifa_prefixlen, prim);

		/* Add network specific broadcasts, when it takes a sense */
		if (ifa->ifa_prefixlen < 31) {
			fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix, 32, prim);
			fib_magic(RTM_NEWROUTE, RTN_BROADCAST, prefix|~mask, 32, prim);
		}
	}
}

static void fib_del_ifaddr(struct in_ifaddr *ifa)
{
	struct in_device *in_dev = ifa->ifa_dev;
	struct net_device *dev = in_dev->dev;
	struct in_ifaddr *ifa1;
	struct in_ifaddr *prim = ifa;
	__be32 brd = ifa->ifa_address|~ifa->ifa_mask;
	__be32 any = ifa->ifa_address&ifa->ifa_mask;
#define LOCAL_OK	1
#define BRD_OK		2
#define BRD0_OK		4
#define BRD1_OK		8
	unsigned ok = 0;

	if (!(ifa->ifa_flags&IFA_F_SECONDARY))
		fib_magic(RTM_DELROUTE, dev->flags&IFF_LOOPBACK ? RTN_LOCAL :
			  RTN_UNICAST, any, ifa->ifa_prefixlen, prim);
	else {
		prim = inet_ifa_byprefix(in_dev, any, ifa->ifa_mask);
		if (prim == NULL) {
			printk(KERN_DEBUG "fib_del_ifaddr: bug: prim == NULL\n");
			return;
		}
	}

	/* Deletion is more complicated than add.
	   We should take care of not to delete too much :-)

	   Scan address list to be sure that addresses are really gone.
	 */

	for (ifa1 = in_dev->ifa_list; ifa1; ifa1 = ifa1->ifa_next) {
		if (ifa->ifa_local == ifa1->ifa_local)
			ok |= LOCAL_OK;
		if (ifa->ifa_broadcast == ifa1->ifa_broadcast)
			ok |= BRD_OK;
		if (brd == ifa1->ifa_broadcast)
			ok |= BRD1_OK;
		if (any == ifa1->ifa_broadcast)
			ok |= BRD0_OK;
	}

	if (!(ok&BRD_OK))
		fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim);
	if (!(ok&BRD1_OK))
		fib_magic(RTM_DELROUTE, RTN_BROADCAST, brd, 32, prim);
	if (!(ok&BRD0_OK))
		fib_magic(RTM_DELROUTE, RTN_BROADCAST, any, 32, prim);
	if (!(ok&LOCAL_OK)) {
		fib_magic(RTM_DELROUTE, RTN_LOCAL, ifa->ifa_local, 32, prim);

		/* Check, that this local address finally disappeared. */
		if (inet_addr_type(ifa->ifa_local) != RTN_LOCAL) {
			/* And the last, but not the least thing.
			   We must flush stray FIB entries.

			   First of all, we scan fib_info list searching
			   for stray nexthop entries, then ignite fib_flush.
			*/
			if (fib_sync_down(ifa->ifa_local, NULL, 0))
				fib_flush();
		}
	}
#undef LOCAL_OK
#undef BRD_OK
#undef BRD0_OK
#undef BRD1_OK
}

static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb )
{

	struct fib_result       res;
	struct flowi            fl = { .mark = frn->fl_mark,
				       .nl_u = { .ip4_u = { .daddr = frn->fl_addr,
							    .tos = frn->fl_tos,
							    .scope = frn->fl_scope } } };

#ifdef CONFIG_IP_MULTIPLE_TABLES
	res.r = NULL;
#endif

	frn->err = -ENOENT;
	if (tb) {
		local_bh_disable();

		frn->tb_id = tb->tb_id;
		frn->err = tb->tb_lookup(tb, &fl, &res);

		if (!frn->err) {
			frn->prefixlen = res.prefixlen;
			frn->nh_sel = res.nh_sel;
			frn->type = res.type;
			frn->scope = res.scope;
			fib_res_put(&res);
		}
		local_bh_enable();
	}
}

static void nl_fib_input(struct sock *sk, int len)
{
	struct sk_buff *skb = NULL;
	struct nlmsghdr *nlh = NULL;
	struct fib_result_nl *frn;
	u32 pid;
	struct fib_table *tb;

	skb = skb_dequeue(&sk->sk_receive_queue);
	if (skb == NULL)
		return;

	nlh = nlmsg_hdr(skb);
	if (skb->len < NLMSG_SPACE(0) || skb->len < nlh->nlmsg_len ||
	    nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*frn))) {
		kfree_skb(skb);
		return;
	}

	frn = (struct fib_result_nl *) NLMSG_DATA(nlh);
	tb = fib_get_table(frn->tb_id_in);

	nl_fib_lookup(frn, tb);

	pid = NETLINK_CB(skb).pid;       /* pid of sending process */
	NETLINK_CB(skb).pid = 0;         /* from kernel */
	NETLINK_CB(skb).dst_group = 0;  /* unicast */
	netlink_unicast(sk, skb, pid, MSG_DONTWAIT);
}

static void nl_fib_lookup_init(void)
{
	netlink_kernel_create(&init_net, NETLINK_FIB_LOOKUP, 0, nl_fib_input,
				NULL, THIS_MODULE);
}

static void fib_disable_ip(struct net_device *dev, int force)
{
	if (fib_sync_down(0, dev, force))
		fib_flush();
	rt_cache_flush(0);
	arp_ifdown(dev);
}

static int fib_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
{
	struct in_ifaddr *ifa = (struct in_ifaddr*)ptr;

	switch (event) {
	case NETDEV_UP:
		fib_add_ifaddr(ifa);
#ifdef CONFIG_IP_ROUTE_MULTIPATH
		fib_sync_up(ifa->ifa_dev->dev);
#endif
		rt_cache_flush(-1);
		break;
	case NETDEV_DOWN:
		fib_del_ifaddr(ifa);
		if (ifa->ifa_dev->ifa_list == NULL) {
			/* Last address was deleted from this interface.
			   Disable IP.
			 */
			fib_disable_ip(ifa->ifa_dev->dev, 1);
		} else {
			rt_cache_flush(-1);
		}
		break;
	}
	return NOTIFY_DONE;
}

static int fib_netdev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
	struct net_device *dev = ptr;
	struct in_device *in_dev = __in_dev_get_rtnl(dev);

	if (dev->nd_net != &init_net)
		return NOTIFY_DONE;

	if (event == NETDEV_UNREGISTER) {
		fib_disable_ip(dev, 2);
		return NOTIFY_DONE;
	}

	if (!in_dev)
		return NOTIFY_DONE;

	switch (event) {
	case NETDEV_UP:
		for_ifa(in_dev) {
			fib_add_ifaddr(ifa);
		} endfor_ifa(in_dev);
#ifdef CONFIG_IP_ROUTE_MULTIPATH
		fib_sync_up(dev);
#endif
		rt_cache_flush(-1);
		break;
	case NETDEV_DOWN:
		fib_disable_ip(dev, 0);
		break;
	case NETDEV_CHANGEMTU:
	case NETDEV_CHANGE:
		rt_cache_flush(0);
		break;
	}
	return NOTIFY_DONE;
}

static struct notifier_block fib_inetaddr_notifier = {
	.notifier_call =fib_inetaddr_event,
};

static struct notifier_block fib_netdev_notifier = {
	.notifier_call =fib_netdev_event,
};

void __init ip_fib_init(void)
{
	unsigned int i;

	for (i = 0; i < FIB_TABLE_HASHSZ; i++)
		INIT_HLIST_HEAD(&fib_table_hash[i]);
#ifndef CONFIG_IP_MULTIPLE_TABLES
	ip_fib_local_table = fib_hash_init(RT_TABLE_LOCAL);
	hlist_add_head_rcu(&ip_fib_local_table->tb_hlist, &fib_table_hash[0]);
	ip_fib_main_table  = fib_hash_init(RT_TABLE_MAIN);
	hlist_add_head_rcu(&ip_fib_main_table->tb_hlist, &fib_table_hash[0]);
#else
	fib4_rules_init();
#endif

	register_netdevice_notifier(&fib_netdev_notifier);
	register_inetaddr_notifier(&fib_inetaddr_notifier);
	nl_fib_lookup_init();

	rtnl_register(PF_INET, RTM_NEWROUTE, inet_rtm_newroute, NULL);
	rtnl_register(PF_INET, RTM_DELROUTE, inet_rtm_delroute, NULL);
	rtnl_register(PF_INET, RTM_GETROUTE, NULL, inet_dump_fib);
}

EXPORT_SYMBOL(inet_addr_type);
EXPORT_SYMBOL(ip_dev_find);
OpenPOWER on IntegriCloud