summaryrefslogtreecommitdiff
path: root/net/appletalk/aarp.c
blob: 54640c01b50cddcbf3f42321361c08b9ebe911c4 (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
/*
 *	AARP:		An implementation of the AppleTalk AARP protocol for
 *			Ethernet 'ELAP'.
 *
 *		Alan Cox  <Alan.Cox@linux.org>
 *
 *	This doesn't fit cleanly with the IP arp. Potentially we can use
 *	the generic neighbour discovery code to clean this up.
 *
 *	FIXME:
 *		We ought to handle the retransmits with a single list and a
 *	separate fast timer for when it is needed.
 *		Use neighbour discovery code.
 *		Token Ring Support.
 *
 *		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.
 *
 *
 *	References:
 *		Inside AppleTalk (2nd Ed).
 *	Fixes:
 *		Jaume Grau	-	flush caches on AARP_PROBE
 *		Rob Newberry	-	Added proxy AARP and AARP proc fs,
 *					moved probing from DDP module.
 *		Arnaldo C. Melo -	don't mangle rx packets
 *
 */

#include <linux/config.h>
#include <linux/if_arp.h>
#include <net/sock.h>
#include <net/datalink.h>
#include <net/psnap.h>
#include <linux/atalk.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

int sysctl_aarp_expiry_time = AARP_EXPIRY_TIME;
int sysctl_aarp_tick_time = AARP_TICK_TIME;
int sysctl_aarp_retransmit_limit = AARP_RETRANSMIT_LIMIT;
int sysctl_aarp_resolve_time = AARP_RESOLVE_TIME;

/* Lists of aarp entries */
/**
 *	struct aarp_entry - AARP entry
 *	@last_sent - Last time we xmitted the aarp request
 *	@packet_queue - Queue of frames wait for resolution
 *	@status - Used for proxy AARP
 *	expires_at - Entry expiry time
 *	target_addr - DDP Address
 *	dev - Device to use
 *	hwaddr - Physical i/f address of target/router
 *	xmit_count - When this hits 10 we give up
 *	next - Next entry in chain
 */
struct aarp_entry {
	/* These first two are only used for unresolved entries */
	unsigned long		last_sent;
	struct sk_buff_head	packet_queue;
	int			status;
	unsigned long		expires_at;
	struct atalk_addr	target_addr;
	struct net_device	*dev;
	char			hwaddr[6];
	unsigned short		xmit_count;
	struct aarp_entry	*next;
};

/* Hashed list of resolved, unresolved and proxy entries */
static struct aarp_entry *resolved[AARP_HASH_SIZE];
static struct aarp_entry *unresolved[AARP_HASH_SIZE];
static struct aarp_entry *proxies[AARP_HASH_SIZE];
static int unresolved_count;

/* One lock protects it all. */
static DEFINE_RWLOCK(aarp_lock);

/* Used to walk the list and purge/kick entries.  */
static struct timer_list aarp_timer;

/*
 *	Delete an aarp queue
 *
 *	Must run under aarp_lock.
 */
static void __aarp_expire(struct aarp_entry *a)
{
	skb_queue_purge(&a->packet_queue);
	kfree(a);
}

/*
 *	Send an aarp queue entry request
 *
 *	Must run under aarp_lock.
 */
static void __aarp_send_query(struct aarp_entry *a)
{
	static unsigned char aarp_eth_multicast[ETH_ALEN] =
					{ 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF };
	struct net_device *dev = a->dev;
	struct elapaarp *eah;
	int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length;
	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
	struct atalk_addr *sat = atalk_find_dev_addr(dev);

	if (!skb)
		return;

	if (!sat) {
		kfree_skb(skb);
		return;
	}

	/* Set up the buffer */
	skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length);
	skb->nh.raw      = skb->h.raw = skb_put(skb, sizeof(*eah));
	skb->protocol    = htons(ETH_P_ATALK);
	skb->dev	 = dev;
	eah		 = aarp_hdr(skb);

	/* Set up the ARP */
	eah->hw_type	 = htons(AARP_HW_TYPE_ETHERNET);
	eah->pa_type	 = htons(ETH_P_ATALK);
	eah->hw_len	 = ETH_ALEN;
	eah->pa_len	 = AARP_PA_ALEN;
	eah->function	 = htons(AARP_REQUEST);

	memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN);

	eah->pa_src_zero = 0;
	eah->pa_src_net	 = sat->s_net;
	eah->pa_src_node = sat->s_node;

	memset(eah->hw_dst, '\0', ETH_ALEN);

	eah->pa_dst_zero = 0;
	eah->pa_dst_net	 = a->target_addr.s_net;
	eah->pa_dst_node = a->target_addr.s_node;

	/* Send it */
	aarp_dl->request(aarp_dl, skb, aarp_eth_multicast);
	/* Update the sending count */
	a->xmit_count++;
	a->last_sent = jiffies;
}

/* This runs under aarp_lock and in softint context, so only atomic memory
 * allocations can be used. */
static void aarp_send_reply(struct net_device *dev, struct atalk_addr *us,
			    struct atalk_addr *them, unsigned char *sha)
{
	struct elapaarp *eah;
	int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length;
	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);

	if (!skb)
		return;

	/* Set up the buffer */
	skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length);
	skb->nh.raw      = skb->h.raw = skb_put(skb, sizeof(*eah));
	skb->protocol    = htons(ETH_P_ATALK);
	skb->dev	 = dev;
	eah		 = aarp_hdr(skb);

	/* Set up the ARP */
	eah->hw_type	 = htons(AARP_HW_TYPE_ETHERNET);
	eah->pa_type	 = htons(ETH_P_ATALK);
	eah->hw_len	 = ETH_ALEN;
	eah->pa_len	 = AARP_PA_ALEN;
	eah->function	 = htons(AARP_REPLY);

	memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN);

	eah->pa_src_zero = 0;
	eah->pa_src_net	 = us->s_net;
	eah->pa_src_node = us->s_node;

	if (!sha)
		memset(eah->hw_dst, '\0', ETH_ALEN);
	else
		memcpy(eah->hw_dst, sha, ETH_ALEN);

	eah->pa_dst_zero = 0;
	eah->pa_dst_net	 = them->s_net;
	eah->pa_dst_node = them->s_node;

	/* Send it */
	aarp_dl->request(aarp_dl, skb, sha);
}

/*
 *	Send probe frames. Called from aarp_probe_network and
 *	aarp_proxy_probe_network.
 */

static void aarp_send_probe(struct net_device *dev, struct atalk_addr *us)
{
	struct elapaarp *eah;
	int len = dev->hard_header_len + sizeof(*eah) + aarp_dl->header_length;
	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
	static unsigned char aarp_eth_multicast[ETH_ALEN] =
					{ 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF };

	if (!skb)
		return;

	/* Set up the buffer */
	skb_reserve(skb, dev->hard_header_len + aarp_dl->header_length);
	skb->nh.raw      = skb->h.raw = skb_put(skb, sizeof(*eah));
	skb->protocol    = htons(ETH_P_ATALK);
	skb->dev	 = dev;
	eah		 = aarp_hdr(skb);

	/* Set up the ARP */
	eah->hw_type	 = htons(AARP_HW_TYPE_ETHERNET);
	eah->pa_type	 = htons(ETH_P_ATALK);
	eah->hw_len	 = ETH_ALEN;
	eah->pa_len	 = AARP_PA_ALEN;
	eah->function	 = htons(AARP_PROBE);

	memcpy(eah->hw_src, dev->dev_addr, ETH_ALEN);

	eah->pa_src_zero = 0;
	eah->pa_src_net	 = us->s_net;
	eah->pa_src_node = us->s_node;

	memset(eah->hw_dst, '\0', ETH_ALEN);

	eah->pa_dst_zero = 0;
	eah->pa_dst_net	 = us->s_net;
	eah->pa_dst_node = us->s_node;

	/* Send it */
	aarp_dl->request(aarp_dl, skb, aarp_eth_multicast);
}

/*
 *	Handle an aarp timer expire
 *
 *	Must run under the aarp_lock.
 */

static void __aarp_expire_timer(struct aarp_entry **n)
{
	struct aarp_entry *t;

	while (*n)
		/* Expired ? */
		if (time_after(jiffies, (*n)->expires_at)) {
			t = *n;
			*n = (*n)->next;
			__aarp_expire(t);
		} else
			n = &((*n)->next);
}

/*
 *	Kick all pending requests 5 times a second.
 *
 *	Must run under the aarp_lock.
 */
static void __aarp_kick(struct aarp_entry **n)
{
	struct aarp_entry *t;

	while (*n)
		/* Expired: if this will be the 11th tx, we delete instead. */
		if ((*n)->xmit_count >= sysctl_aarp_retransmit_limit) {
			t = *n;
			*n = (*n)->next;
			__aarp_expire(t);
		} else {
			__aarp_send_query(*n);
			n = &((*n)->next);
		}
}

/*
 *	A device has gone down. Take all entries referring to the device
 *	and remove them.
 *
 *	Must run under the aarp_lock.
 */
static void __aarp_expire_device(struct aarp_entry **n, struct net_device *dev)
{
	struct aarp_entry *t;

	while (*n)
		if ((*n)->dev == dev) {
			t = *n;
			*n = (*n)->next;
			__aarp_expire(t);
		} else
			n = &((*n)->next);
}

/* Handle the timer event */
static void aarp_expire_timeout(unsigned long unused)
{
	int ct;

	write_lock_bh(&aarp_lock);

	for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
		__aarp_expire_timer(&resolved[ct]);
		__aarp_kick(&unresolved[ct]);
		__aarp_expire_timer(&unresolved[ct]);
		__aarp_expire_timer(&proxies[ct]);
	}

	write_unlock_bh(&aarp_lock);
	mod_timer(&aarp_timer, jiffies +
			       (unresolved_count ? sysctl_aarp_tick_time :
				sysctl_aarp_expiry_time));
}

/* Network device notifier chain handler. */
static int aarp_device_event(struct notifier_block *this, unsigned long event,
			     void *ptr)
{
	int ct;

	if (event == NETDEV_DOWN) {
		write_lock_bh(&aarp_lock);

		for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
			__aarp_expire_device(&resolved[ct], ptr);
			__aarp_expire_device(&unresolved[ct], ptr);
			__aarp_expire_device(&proxies[ct], ptr);
		}

		write_unlock_bh(&aarp_lock);
	}
	return NOTIFY_DONE;
}

/* Expire all entries in a hash chain */
static void __aarp_expire_all(struct aarp_entry **n)
{
	struct aarp_entry *t;

	while (*n) {
		t = *n;
		*n = (*n)->next;
		__aarp_expire(t);
	}
}

/* Cleanup all hash chains -- module unloading */
static void aarp_purge(void)
{
	int ct;

	write_lock_bh(&aarp_lock);
	for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
		__aarp_expire_all(&resolved[ct]);
		__aarp_expire_all(&unresolved[ct]);
		__aarp_expire_all(&proxies[ct]);
	}
	write_unlock_bh(&aarp_lock);
}

/*
 *	Create a new aarp entry.  This must use GFP_ATOMIC because it
 *	runs while holding spinlocks.
 */
static struct aarp_entry *aarp_alloc(void)
{
	struct aarp_entry *a = kmalloc(sizeof(*a), GFP_ATOMIC);

	if (a)
		skb_queue_head_init(&a->packet_queue);
	return a;
}

/*
 * Find an entry. We might return an expired but not yet purged entry. We
 * don't care as it will do no harm.
 *
 * This must run under the aarp_lock.
 */
static struct aarp_entry *__aarp_find_entry(struct aarp_entry *list,
					    struct net_device *dev,
					    struct atalk_addr *sat)
{
	while (list) {
		if (list->target_addr.s_net == sat->s_net &&
		    list->target_addr.s_node == sat->s_node &&
		    list->dev == dev)
			break;
		list = list->next;
	}

	return list;
}

/* Called from the DDP code, and thus must be exported. */
void aarp_proxy_remove(struct net_device *dev, struct atalk_addr *sa)
{
	int hash = sa->s_node % (AARP_HASH_SIZE - 1);
	struct aarp_entry *a;

	write_lock_bh(&aarp_lock);

	a = __aarp_find_entry(proxies[hash], dev, sa);
	if (a)
		a->expires_at = jiffies - 1;

	write_unlock_bh(&aarp_lock);
}

/* This must run under aarp_lock. */
static struct atalk_addr *__aarp_proxy_find(struct net_device *dev,
					    struct atalk_addr *sa)
{
	int hash = sa->s_node % (AARP_HASH_SIZE - 1);
	struct aarp_entry *a = __aarp_find_entry(proxies[hash], dev, sa);

	return a ? sa : NULL;
}

/*
 * Probe a Phase 1 device or a device that requires its Net:Node to
 * be set via an ioctl.
 */
static void aarp_send_probe_phase1(struct atalk_iface *iface)
{
	struct ifreq atreq;
	struct sockaddr_at *sa = (struct sockaddr_at *)&atreq.ifr_addr;

	sa->sat_addr.s_node = iface->address.s_node;
	sa->sat_addr.s_net = ntohs(iface->address.s_net);

	/* We pass the Net:Node to the drivers/cards by a Device ioctl. */
	if (!(iface->dev->do_ioctl(iface->dev, &atreq, SIOCSIFADDR))) {
		(void)iface->dev->do_ioctl(iface->dev, &atreq, SIOCGIFADDR);
		if (iface->address.s_net != htons(sa->sat_addr.s_net) ||
		    iface->address.s_node != sa->sat_addr.s_node)
			iface->status |= ATIF_PROBE_FAIL;

		iface->address.s_net  = htons(sa->sat_addr.s_net);
		iface->address.s_node = sa->sat_addr.s_node;
	}
}


void aarp_probe_network(struct atalk_iface *atif)
{
	if (atif->dev->type == ARPHRD_LOCALTLK ||
	    atif->dev->type == ARPHRD_PPP)
		aarp_send_probe_phase1(atif);
	else {
		unsigned int count;

		for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) {
			aarp_send_probe(atif->dev, &atif->address);

			/* Defer 1/10th */
			current->state = TASK_INTERRUPTIBLE;
			schedule_timeout(HZ / 10);

			if (atif->status & ATIF_PROBE_FAIL)
				break;
		}
	}
}

int aarp_proxy_probe_network(struct atalk_iface *atif, struct atalk_addr *sa)
{
	int hash, retval = -EPROTONOSUPPORT;
	struct aarp_entry *entry;
	unsigned int count;

	/*
	 * we don't currently support LocalTalk or PPP for proxy AARP;
	 * if someone wants to try and add it, have fun
	 */
	if (atif->dev->type == ARPHRD_LOCALTLK ||
	    atif->dev->type == ARPHRD_PPP)
		goto out;

	/*
	 * create a new AARP entry with the flags set to be published --
	 * we need this one to hang around even if it's in use
	 */
	entry = aarp_alloc();
	retval = -ENOMEM;
	if (!entry)
		goto out;

	entry->expires_at = -1;
	entry->status = ATIF_PROBE;
	entry->target_addr.s_node = sa->s_node;
	entry->target_addr.s_net = sa->s_net;
	entry->dev = atif->dev;

	write_lock_bh(&aarp_lock);

	hash = sa->s_node % (AARP_HASH_SIZE - 1);
	entry->next = proxies[hash];
	proxies[hash] = entry;

	for (count = 0; count < AARP_RETRANSMIT_LIMIT; count++) {
		aarp_send_probe(atif->dev, sa);

		/* Defer 1/10th */
		current->state = TASK_INTERRUPTIBLE;
		write_unlock_bh(&aarp_lock);
		schedule_timeout(HZ / 10);
		write_lock_bh(&aarp_lock);

		if (entry->status & ATIF_PROBE_FAIL)
			break;
	}

	if (entry->status & ATIF_PROBE_FAIL) {
		entry->expires_at = jiffies - 1; /* free the entry */
		retval = -EADDRINUSE; /* return network full */
	} else { /* clear the probing flag */
		entry->status &= ~ATIF_PROBE;
		retval = 1;
	}

	write_unlock_bh(&aarp_lock);
out:
	return retval;
}

/* Send a DDP frame */
int aarp_send_ddp(struct net_device *dev, struct sk_buff *skb,
		  struct atalk_addr *sa, void *hwaddr)
{
	static char ddp_eth_multicast[ETH_ALEN] =
		{ 0x09, 0x00, 0x07, 0xFF, 0xFF, 0xFF };
	int hash;
	struct aarp_entry *a;

	skb->nh.raw = skb->data;

	/* Check for LocalTalk first */
	if (dev->type == ARPHRD_LOCALTLK) {
		struct atalk_addr *at = atalk_find_dev_addr(dev);
		struct ddpehdr *ddp = (struct ddpehdr *)skb->data;
		int ft = 2;

		/*
		 * Compressible ?
		 *
		 * IFF: src_net == dest_net == device_net
		 * (zero matches anything)
		 */

		if ((!ddp->deh_snet || at->s_net == ddp->deh_snet) &&
		    (!ddp->deh_dnet || at->s_net == ddp->deh_dnet)) {
			skb_pull(skb, sizeof(*ddp) - 4);

			/*
			 *	The upper two remaining bytes are the port
			 *	numbers	we just happen to need. Now put the
			 *	length in the lower two.
			 */
			*((__u16 *)skb->data) = htons(skb->len);
			ft = 1;
		}
		/*
		 * Nice and easy. No AARP type protocols occur here so we can
		 * just shovel it out with a 3 byte LLAP header
		 */

		skb_push(skb, 3);
		skb->data[0] = sa->s_node;
		skb->data[1] = at->s_node;
		skb->data[2] = ft;
		skb->dev     = dev;
		goto sendit;
	}

	/* On a PPP link we neither compress nor aarp.  */
	if (dev->type == ARPHRD_PPP) {
		skb->protocol = htons(ETH_P_PPPTALK);
		skb->dev = dev;
		goto sendit;
	}

	/* Non ELAP we cannot do. */
	if (dev->type != ARPHRD_ETHER)
		return -1;

	skb->dev = dev;
	skb->protocol = htons(ETH_P_ATALK);
	hash = sa->s_node % (AARP_HASH_SIZE - 1);

	/* Do we have a resolved entry? */
	if (sa->s_node == ATADDR_BCAST) {
		/* Send it */
		ddp_dl->request(ddp_dl, skb, ddp_eth_multicast);
		goto sent;
	}

	write_lock_bh(&aarp_lock);
	a = __aarp_find_entry(resolved[hash], dev, sa);

	if (a) { /* Return 1 and fill in the address */
		a->expires_at = jiffies + (sysctl_aarp_expiry_time * 10);
		ddp_dl->request(ddp_dl, skb, a->hwaddr);
		write_unlock_bh(&aarp_lock);
		goto sent;
	}

	/* Do we have an unresolved entry: This is the less common path */
	a = __aarp_find_entry(unresolved[hash], dev, sa);
	if (a) { /* Queue onto the unresolved queue */
		skb_queue_tail(&a->packet_queue, skb);
		goto out_unlock;
	}

	/* Allocate a new entry */
	a = aarp_alloc();
	if (!a) {
		/* Whoops slipped... good job it's an unreliable protocol 8) */
		write_unlock_bh(&aarp_lock);
		return -1;
	}

	/* Set up the queue */
	skb_queue_tail(&a->packet_queue, skb);
	a->expires_at	 = jiffies + sysctl_aarp_resolve_time;
	a->dev		 = dev;
	a->next		 = unresolved[hash];
	a->target_addr	 = *sa;
	a->xmit_count	 = 0;
	unresolved[hash] = a;
	unresolved_count++;

	/* Send an initial request for the address */
	__aarp_send_query(a);

	/*
	 * Switch to fast timer if needed (That is if this is the first
	 * unresolved entry to get added)
	 */

	if (unresolved_count == 1)
		mod_timer(&aarp_timer, jiffies + sysctl_aarp_tick_time);

	/* Now finally, it is safe to drop the lock. */
out_unlock:
	write_unlock_bh(&aarp_lock);

	/* Tell the ddp layer we have taken over for this frame. */
	return 0;

sendit:
	if (skb->sk)
		skb->priority = skb->sk->sk_priority;
	dev_queue_xmit(skb);
sent:
	return 1;
}

/*
 *	An entry in the aarp unresolved queue has become resolved. Send
 *	all the frames queued under it.
 *
 *	Must run under aarp_lock.
 */
static void __aarp_resolved(struct aarp_entry **list, struct aarp_entry *a,
			    int hash)
{
	struct sk_buff *skb;

	while (*list)
		if (*list == a) {
			unresolved_count--;
			*list = a->next;

			/* Move into the resolved list */
			a->next = resolved[hash];
			resolved[hash] = a;

			/* Kick frames off */
			while ((skb = skb_dequeue(&a->packet_queue)) != NULL) {
				a->expires_at = jiffies +
						sysctl_aarp_expiry_time * 10;
				ddp_dl->request(ddp_dl, skb, a->hwaddr);
			}
		} else
			list = &((*list)->next);
}

/*
 *	This is called by the SNAP driver whenever we see an AARP SNAP
 *	frame. We currently only support Ethernet.
 */
static int aarp_rcv(struct sk_buff *skb, struct net_device *dev,
		    struct packet_type *pt)
{
	struct elapaarp *ea = aarp_hdr(skb);
	int hash, ret = 0;
	__u16 function;
	struct aarp_entry *a;
	struct atalk_addr sa, *ma, da;
	struct atalk_iface *ifa;

	/* We only do Ethernet SNAP AARP. */
	if (dev->type != ARPHRD_ETHER)
		goto out0;

	/* Frame size ok? */
	if (!skb_pull(skb, sizeof(*ea)))
		goto out0;

	function = ntohs(ea->function);

	/* Sanity check fields. */
	if (function < AARP_REQUEST || function > AARP_PROBE ||
	    ea->hw_len != ETH_ALEN || ea->pa_len != AARP_PA_ALEN ||
	    ea->pa_src_zero || ea->pa_dst_zero)
		goto out0;

	/* Looks good. */
	hash = ea->pa_src_node % (AARP_HASH_SIZE - 1);

	/* Build an address. */
	sa.s_node = ea->pa_src_node;
	sa.s_net = ea->pa_src_net;

	/* Process the packet. Check for replies of me. */
	ifa = atalk_find_dev(dev);
	if (!ifa)
		goto out1;

	if (ifa->status & ATIF_PROBE &&
	    ifa->address.s_node == ea->pa_dst_node &&
	    ifa->address.s_net == ea->pa_dst_net) {
		ifa->status |= ATIF_PROBE_FAIL; /* Fail the probe (in use) */
		goto out1;
	}

	/* Check for replies of proxy AARP entries */
	da.s_node = ea->pa_dst_node;
	da.s_net  = ea->pa_dst_net;

	write_lock_bh(&aarp_lock);
	a = __aarp_find_entry(proxies[hash], dev, &da);

	if (a && a->status & ATIF_PROBE) {
		a->status |= ATIF_PROBE_FAIL;
		/*
		 * we do not respond to probe or request packets for
		 * this address while we are probing this address
		 */
		goto unlock;
	}

	switch (function) {
		case AARP_REPLY:
			if (!unresolved_count)	/* Speed up */
				break;

			/* Find the entry.  */
			a = __aarp_find_entry(unresolved[hash], dev, &sa);
			if (!a || dev != a->dev)
				break;

			/* We can fill one in - this is good. */
			memcpy(a->hwaddr, ea->hw_src, ETH_ALEN);
			__aarp_resolved(&unresolved[hash], a, hash);
			if (!unresolved_count)
				mod_timer(&aarp_timer,
					  jiffies + sysctl_aarp_expiry_time);
			break;

		case AARP_REQUEST:
		case AARP_PROBE:

			/*
			 * If it is my address set ma to my address and reply.
			 * We can treat probe and request the same.  Probe
			 * simply means we shouldn't cache the querying host,
			 * as in a probe they are proposing an address not
			 * using one.
			 *
			 * Support for proxy-AARP added. We check if the
			 * address is one of our proxies before we toss the
			 * packet out.
			 */

			sa.s_node = ea->pa_dst_node;
			sa.s_net  = ea->pa_dst_net;

			/* See if we have a matching proxy. */
			ma = __aarp_proxy_find(dev, &sa);
			if (!ma)
				ma = &ifa->address;
			else { /* We need to make a copy of the entry. */
				da.s_node = sa.s_node;
				da.s_net = da.s_net;
				ma = &da;
			}

			if (function == AARP_PROBE) {
				/*
				 * A probe implies someone trying to get an
				 * address. So as a precaution flush any
				 * entries we have for this address.
				 */
				struct aarp_entry *a;

				a = __aarp_find_entry(resolved[sa.s_node %
							  (AARP_HASH_SIZE - 1)],
						      skb->dev, &sa);

				/*
				 * Make it expire next tick - that avoids us
				 * getting into a probe/flush/learn/probe/
				 * flush/learn cycle during probing of a slow
				 * to respond host addr.
				 */
				if (a) {
					a->expires_at = jiffies - 1;
					mod_timer(&aarp_timer, jiffies +
							sysctl_aarp_tick_time);
				}
			}

			if (sa.s_node != ma->s_node)
				break;

			if (sa.s_net && ma->s_net && sa.s_net != ma->s_net)
				break;

			sa.s_node = ea->pa_src_node;
			sa.s_net = ea->pa_src_net;

			/* aarp_my_address has found the address to use for us.
			*/
			aarp_send_reply(dev, ma, &sa, ea->hw_src);
			break;
	}

unlock:
	write_unlock_bh(&aarp_lock);
out1:
	ret = 1;
out0:
	kfree_skb(skb);
	return ret;
}

static struct notifier_block aarp_notifier = {
	.notifier_call = aarp_device_event,
};

static unsigned char aarp_snap_id[] = { 0x00, 0x00, 0x00, 0x80, 0xF3 };

void __init aarp_proto_init(void)
{
	aarp_dl = register_snap_client(aarp_snap_id, aarp_rcv);
	if (!aarp_dl)
		printk(KERN_CRIT "Unable to register AARP with SNAP.\n");
	init_timer(&aarp_timer);
	aarp_timer.function = aarp_expire_timeout;
	aarp_timer.data	    = 0;
	aarp_timer.expires  = jiffies + sysctl_aarp_expiry_time;
	add_timer(&aarp_timer);
	register_netdevice_notifier(&aarp_notifier);
}

/* Remove the AARP entries associated with a device. */
void aarp_device_down(struct net_device *dev)
{
	int ct;

	write_lock_bh(&aarp_lock);

	for (ct = 0; ct < AARP_HASH_SIZE; ct++) {
		__aarp_expire_device(&resolved[ct], dev);
		__aarp_expire_device(&unresolved[ct], dev);
		__aarp_expire_device(&proxies[ct], dev);
	}

	write_unlock_bh(&aarp_lock);
}

#ifdef CONFIG_PROC_FS
struct aarp_iter_state {
	int bucket;
	struct aarp_entry **table;
};

/*
 * Get the aarp entry that is in the chain described
 * by the iterator. 
 * If pos is set then skip till that index.
 * pos = 1 is the first entry
 */
static struct aarp_entry *iter_next(struct aarp_iter_state *iter, loff_t *pos)
{
	int ct = iter->bucket;
	struct aarp_entry **table = iter->table;
	loff_t off = 0;
	struct aarp_entry *entry;
	
 rescan:
	while(ct < AARP_HASH_SIZE) {
		for (entry = table[ct]; entry; entry = entry->next) {
			if (!pos || ++off == *pos) {
				iter->table = table;
				iter->bucket = ct;
				return entry;
			}
		}
		++ct;
	}

	if (table == resolved) {
		ct = 0;
		table = unresolved;
		goto rescan;
	}
	if (table == unresolved) {
		ct = 0;
		table = proxies;
		goto rescan;
	}
	return NULL;
}

static void *aarp_seq_start(struct seq_file *seq, loff_t *pos)
{
	struct aarp_iter_state *iter = seq->private;

	read_lock_bh(&aarp_lock);
	iter->table     = resolved;
	iter->bucket    = 0;

	return *pos ? iter_next(iter, pos) : SEQ_START_TOKEN;
}

static void *aarp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct aarp_entry *entry = v;
	struct aarp_iter_state *iter = seq->private;

	++*pos;

	/* first line after header */
	if (v == SEQ_START_TOKEN) 
		entry = iter_next(iter, NULL);
		
	/* next entry in current bucket */
	else if (entry->next)
		entry = entry->next;

	/* next bucket or table */
	else {
		++iter->bucket;
		entry = iter_next(iter, NULL);
	}
	return entry;
}

static void aarp_seq_stop(struct seq_file *seq, void *v)
{
	read_unlock_bh(&aarp_lock);
}

static const char *dt2str(unsigned long ticks)
{
	static char buf[32];

	sprintf(buf, "%ld.%02ld", ticks / HZ, ((ticks % HZ) * 100 ) / HZ);

	return buf;
}

static int aarp_seq_show(struct seq_file *seq, void *v)
{
	struct aarp_iter_state *iter = seq->private;
	struct aarp_entry *entry = v;
	unsigned long now = jiffies;

	if (v == SEQ_START_TOKEN)
		seq_puts(seq, 
			 "Address  Interface   Hardware Address"
			 "   Expires LastSend  Retry Status\n");
	else {
		seq_printf(seq, "%04X:%02X  %-12s",
			   ntohs(entry->target_addr.s_net),
			   (unsigned int) entry->target_addr.s_node,
			   entry->dev ? entry->dev->name : "????");
		seq_printf(seq, "%02X:%02X:%02X:%02X:%02X:%02X",
			   entry->hwaddr[0] & 0xFF,
			   entry->hwaddr[1] & 0xFF,
			   entry->hwaddr[2] & 0xFF,
			   entry->hwaddr[3] & 0xFF,
			   entry->hwaddr[4] & 0xFF,
			   entry->hwaddr[5] & 0xFF);
		seq_printf(seq, " %8s",
			   dt2str((long)entry->expires_at - (long)now));
		if (iter->table == unresolved)
			seq_printf(seq, " %8s %6hu",
				   dt2str(now - entry->last_sent),
				   entry->xmit_count);
		else
			seq_puts(seq, "                ");
		seq_printf(seq, " %s\n",
			   (iter->table == resolved) ? "resolved"
			   : (iter->table == unresolved) ? "unresolved"
			   : (iter->table == proxies) ? "proxies"
			   : "unknown");
	}				 
	return 0;
}

static struct seq_operations aarp_seq_ops = {
	.start  = aarp_seq_start,
	.next   = aarp_seq_next,
	.stop   = aarp_seq_stop,
	.show   = aarp_seq_show,
};

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

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

	seq	     = file->private_data;
	seq->private = s;
	memset(s, 0, sizeof(*s));
out:
	return rc;
out_kfree:
	kfree(s);
	goto out;
}

struct file_operations atalk_seq_arp_fops = {
	.owner		= THIS_MODULE,
	.open           = aarp_seq_open,
	.read           = seq_read,
	.llseek         = seq_lseek,
	.release	= seq_release_private,
};
#endif

/* General module cleanup. Called from cleanup_module() in ddp.c. */
void aarp_cleanup_module(void)
{
	del_timer_sync(&aarp_timer);
	unregister_netdevice_notifier(&aarp_notifier);
	unregister_snap_client(aarp_dl);
	aarp_purge();
}