summaryrefslogtreecommitdiff
path: root/drivers/net/wan/hdlc_fr.c
blob: 72250fe0a1dff0f3dd66e7f746e9b4dcde15ea8e (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
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic HDLC support routines for Linux
 * Frame Relay support
 *
 * Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
 *

	Theory of PVC state

 DCE mode:

 (exist,new) -> 0,0 when "PVC create" or if "link unreliable"
	 0,x -> 1,1 if "link reliable" when sending FULL STATUS
	 1,1 -> 1,0 if received FULL STATUS ACK

 (active)    -> 0 when "ifconfig PVC down" or "link unreliable" or "PVC create"
	     -> 1 when "PVC up" and (exist,new) = 1,0

 DTE mode:
 (exist,new,active) = FULL STATUS if "link reliable"
		    = 0, 0, 0 if "link unreliable"
 No LMI:
 active = open and "link reliable"
 exist = new = not used

 CCITT LMI: ITU-T Q.933 Annex A
 ANSI LMI: ANSI T1.617 Annex D
 CISCO LMI: the original, aka "Gang of Four" LMI

*/

#include <linux/errno.h>
#include <linux/etherdevice.h>
#include <linux/hdlc.h>
#include <linux/if_arp.h>
#include <linux/inetdevice.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pkt_sched.h>
#include <linux/poll.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/slab.h>

#undef DEBUG_PKT
#undef DEBUG_ECN
#undef DEBUG_LINK
#undef DEBUG_PROTO
#undef DEBUG_PVC

#define FR_UI			0x03
#define FR_PAD			0x00

#define NLPID_IP		0xCC
#define NLPID_IPV6		0x8E
#define NLPID_SNAP		0x80
#define NLPID_PAD		0x00
#define NLPID_CCITT_ANSI_LMI	0x08
#define NLPID_CISCO_LMI		0x09

#define LMI_CCITT_ANSI_DLCI	   0 /* LMI DLCI */
#define LMI_CISCO_DLCI		1023

#define LMI_CALLREF		0x00 /* Call Reference */
#define LMI_ANSI_LOCKSHIFT	0x95 /* ANSI locking shift */
#define LMI_ANSI_CISCO_REPTYPE	0x01 /* report type */
#define LMI_CCITT_REPTYPE	0x51
#define LMI_ANSI_CISCO_ALIVE	0x03 /* keep alive */
#define LMI_CCITT_ALIVE		0x53
#define LMI_ANSI_CISCO_PVCSTAT	0x07 /* PVC status */
#define LMI_CCITT_PVCSTAT	0x57

#define LMI_FULLREP		0x00 /* full report  */
#define LMI_INTEGRITY		0x01 /* link integrity report */
#define LMI_SINGLE		0x02 /* single PVC report */

#define LMI_STATUS_ENQUIRY      0x75
#define LMI_STATUS              0x7D /* reply */

#define LMI_REPT_LEN               1 /* report type element length */
#define LMI_INTEG_LEN              2 /* link integrity element length */

#define LMI_CCITT_CISCO_LENGTH	  13 /* LMI frame lengths */
#define LMI_ANSI_LENGTH		  14

struct fr_hdr {
#if defined(__LITTLE_ENDIAN_BITFIELD)
	unsigned ea1:	1;
	unsigned cr:	1;
	unsigned dlcih:	6;

	unsigned ea2:	1;
	unsigned de:	1;
	unsigned becn:	1;
	unsigned fecn:	1;
	unsigned dlcil:	4;
#else
	unsigned dlcih:	6;
	unsigned cr:	1;
	unsigned ea1:	1;

	unsigned dlcil:	4;
	unsigned fecn:	1;
	unsigned becn:	1;
	unsigned de:	1;
	unsigned ea2:	1;
#endif
} __packed;

struct pvc_device {
	struct net_device *frad;
	struct net_device *main;
	struct net_device *ether;	/* bridged Ethernet interface	*/
	struct pvc_device *next;	/* Sorted in ascending DLCI order */
	int dlci;
	int open_count;

	struct {
		unsigned int new: 1;
		unsigned int active: 1;
		unsigned int exist: 1;
		unsigned int deleted: 1;
		unsigned int fecn: 1;
		unsigned int becn: 1;
		unsigned int bandwidth;	/* Cisco LMI reporting only */
	} state;
};

struct frad_state {
	fr_proto settings;
	struct pvc_device *first_pvc;
	int dce_pvc_count;

	struct timer_list timer;
	struct net_device *dev;
	unsigned long last_poll;
	int reliable;
	int dce_changed;
	int request;
	int fullrep_sent;
	u32 last_errors; /* last errors bit list */
	u8 n391cnt;
	u8 txseq; /* TX sequence number */
	u8 rxseq; /* RX sequence number */
};

static int fr_ioctl(struct net_device *dev, struct ifreq *ifr);

static inline u16 q922_to_dlci(u8 *hdr)
{
	return ((hdr[0] & 0xFC) << 2) | ((hdr[1] & 0xF0) >> 4);
}

static inline void dlci_to_q922(u8 *hdr, u16 dlci)
{
	hdr[0] = (dlci >> 2) & 0xFC;
	hdr[1] = ((dlci << 4) & 0xF0) | 0x01;
}

static inline struct frad_state *state(hdlc_device *hdlc)
{
	return (struct frad_state *)(hdlc->state);
}

static inline struct pvc_device *find_pvc(hdlc_device *hdlc, u16 dlci)
{
	struct pvc_device *pvc = state(hdlc)->first_pvc;

	while (pvc) {
		if (pvc->dlci == dlci)
			return pvc;
		if (pvc->dlci > dlci)
			return NULL; /* the list is sorted */
		pvc = pvc->next;
	}

	return NULL;
}

static struct pvc_device *add_pvc(struct net_device *dev, u16 dlci)
{
	hdlc_device *hdlc = dev_to_hdlc(dev);
	struct pvc_device *pvc, **pvc_p = &state(hdlc)->first_pvc;

	while (*pvc_p) {
		if ((*pvc_p)->dlci == dlci)
			return *pvc_p;
		if ((*pvc_p)->dlci > dlci)
			break;	/* the list is sorted */
		pvc_p = &(*pvc_p)->next;
	}

	pvc = kzalloc(sizeof(*pvc), GFP_ATOMIC);
#ifdef DEBUG_PVC
	printk(KERN_DEBUG "add_pvc: allocated pvc %p, frad %p\n", pvc, dev);
#endif
	if (!pvc)
		return NULL;

	pvc->dlci = dlci;
	pvc->frad = dev;
	pvc->next = *pvc_p;	/* Put it in the chain */
	*pvc_p = pvc;
	return pvc;
}

static inline int pvc_is_used(struct pvc_device *pvc)
{
	return pvc->main || pvc->ether;
}

static inline void pvc_carrier(int on, struct pvc_device *pvc)
{
	if (on) {
		if (pvc->main)
			if (!netif_carrier_ok(pvc->main))
				netif_carrier_on(pvc->main);
		if (pvc->ether)
			if (!netif_carrier_ok(pvc->ether))
				netif_carrier_on(pvc->ether);
	} else {
		if (pvc->main)
			if (netif_carrier_ok(pvc->main))
				netif_carrier_off(pvc->main);
		if (pvc->ether)
			if (netif_carrier_ok(pvc->ether))
				netif_carrier_off(pvc->ether);
	}
}

static inline void delete_unused_pvcs(hdlc_device *hdlc)
{
	struct pvc_device **pvc_p = &state(hdlc)->first_pvc;

	while (*pvc_p) {
		if (!pvc_is_used(*pvc_p)) {
			struct pvc_device *pvc = *pvc_p;
#ifdef DEBUG_PVC
			printk(KERN_DEBUG "freeing unused pvc: %p\n", pvc);
#endif
			*pvc_p = pvc->next;
			kfree(pvc);
			continue;
		}
		pvc_p = &(*pvc_p)->next;
	}
}

static inline struct net_device **get_dev_p(struct pvc_device *pvc,
					    int type)
{
	if (type == ARPHRD_ETHER)
		return &pvc->ether;
	else
		return &pvc->main;
}

static int fr_hard_header(struct sk_buff *skb, u16 dlci)
{
	if (!skb->dev) { /* Control packets */
		switch (dlci) {
		case LMI_CCITT_ANSI_DLCI:
			skb_push(skb, 4);
			skb->data[3] = NLPID_CCITT_ANSI_LMI;
			break;

		case LMI_CISCO_DLCI:
			skb_push(skb, 4);
			skb->data[3] = NLPID_CISCO_LMI;
			break;

		default:
			return -EINVAL;
		}

	} else if (skb->dev->type == ARPHRD_DLCI) {
		switch (skb->protocol) {
		case htons(ETH_P_IP):
			skb_push(skb, 4);
			skb->data[3] = NLPID_IP;
			break;

		case htons(ETH_P_IPV6):
			skb_push(skb, 4);
			skb->data[3] = NLPID_IPV6;
			break;

		default:
			skb_push(skb, 10);
			skb->data[3] = FR_PAD;
			skb->data[4] = NLPID_SNAP;
			/* OUI 00-00-00 indicates an Ethertype follows */
			skb->data[5] = 0x00;
			skb->data[6] = 0x00;
			skb->data[7] = 0x00;
			/* This should be an Ethertype: */
			*(__be16 *)(skb->data + 8) = skb->protocol;
		}

	} else if (skb->dev->type == ARPHRD_ETHER) {
		skb_push(skb, 10);
		skb->data[3] = FR_PAD;
		skb->data[4] = NLPID_SNAP;
		/* OUI 00-80-C2 stands for the 802.1 organization */
		skb->data[5] = 0x00;
		skb->data[6] = 0x80;
		skb->data[7] = 0xC2;
		/* PID 00-07 stands for Ethernet frames without FCS */
		skb->data[8] = 0x00;
		skb->data[9] = 0x07;

	} else {
		return -EINVAL;
	}

	dlci_to_q922(skb->data, dlci);
	skb->data[2] = FR_UI;
	return 0;
}

static int pvc_open(struct net_device *dev)
{
	struct pvc_device *pvc = dev->ml_priv;

	if ((pvc->frad->flags & IFF_UP) == 0)
		return -EIO;  /* Frad must be UP in order to activate PVC */

	if (pvc->open_count++ == 0) {
		hdlc_device *hdlc = dev_to_hdlc(pvc->frad);

		if (state(hdlc)->settings.lmi == LMI_NONE)
			pvc->state.active = netif_carrier_ok(pvc->frad);

		pvc_carrier(pvc->state.active, pvc);
		state(hdlc)->dce_changed = 1;
	}
	return 0;
}

static int pvc_close(struct net_device *dev)
{
	struct pvc_device *pvc = dev->ml_priv;

	if (--pvc->open_count == 0) {
		hdlc_device *hdlc = dev_to_hdlc(pvc->frad);

		if (state(hdlc)->settings.lmi == LMI_NONE)
			pvc->state.active = 0;

		if (state(hdlc)->settings.dce) {
			state(hdlc)->dce_changed = 1;
			pvc->state.active = 0;
		}
	}
	return 0;
}

static int pvc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
	struct pvc_device *pvc = dev->ml_priv;
	fr_proto_pvc_info info;

	if (ifr->ifr_settings.type == IF_GET_PROTO) {
		if (dev->type == ARPHRD_ETHER)
			ifr->ifr_settings.type = IF_PROTO_FR_ETH_PVC;
		else
			ifr->ifr_settings.type = IF_PROTO_FR_PVC;

		if (ifr->ifr_settings.size < sizeof(info)) {
			/* data size wanted */
			ifr->ifr_settings.size = sizeof(info);
			return -ENOBUFS;
		}

		info.dlci = pvc->dlci;
		memcpy(info.master, pvc->frad->name, IFNAMSIZ);
		if (copy_to_user(ifr->ifr_settings.ifs_ifsu.fr_pvc_info,
				 &info, sizeof(info)))
			return -EFAULT;
		return 0;
	}

	return -EINVAL;
}

static netdev_tx_t pvc_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct pvc_device *pvc = dev->ml_priv;

	if (!pvc->state.active)
		goto drop;

	if (dev->type == ARPHRD_ETHER) {
		int pad = ETH_ZLEN - skb->len;

		if (pad > 0) { /* Pad the frame with zeros */
			if (__skb_pad(skb, pad, false))
				goto drop;
			skb_put(skb, pad);
		}
	}

	/* We already requested the header space with dev->needed_headroom.
	 * So this is just a protection in case the upper layer didn't take
	 * dev->needed_headroom into consideration.
	 */
	if (skb_headroom(skb) < 10) {
		struct sk_buff *skb2 = skb_realloc_headroom(skb, 10);

		if (!skb2)
			goto drop;
		dev_kfree_skb(skb);
		skb = skb2;
	}

	skb->dev = dev;
	if (fr_hard_header(skb, pvc->dlci))
		goto drop;

	dev->stats.tx_bytes += skb->len;
	dev->stats.tx_packets++;
	if (pvc->state.fecn) /* TX Congestion counter */
		dev->stats.tx_compressed++;
	skb->dev = pvc->frad;
	skb->protocol = htons(ETH_P_HDLC);
	skb_reset_network_header(skb);
	dev_queue_xmit(skb);
	return NETDEV_TX_OK;

drop:
	dev->stats.tx_dropped++;
	kfree_skb(skb);
	return NETDEV_TX_OK;
}

static inline void fr_log_dlci_active(struct pvc_device *pvc)
{
	netdev_info(pvc->frad, "DLCI %d [%s%s%s]%s %s\n",
		    pvc->dlci,
		    pvc->main ? pvc->main->name : "",
		    pvc->main && pvc->ether ? " " : "",
		    pvc->ether ? pvc->ether->name : "",
		    pvc->state.new ? " new" : "",
		    !pvc->state.exist ? "deleted" :
		    pvc->state.active ? "active" : "inactive");
}

static inline u8 fr_lmi_nextseq(u8 x)
{
	x++;
	return x ? x : 1;
}

static void fr_lmi_send(struct net_device *dev, int fullrep)
{
	hdlc_device *hdlc = dev_to_hdlc(dev);
	struct sk_buff *skb;
	struct pvc_device *pvc = state(hdlc)->first_pvc;
	int lmi = state(hdlc)->settings.lmi;
	int dce = state(hdlc)->settings.dce;
	int len = lmi == LMI_ANSI ? LMI_ANSI_LENGTH : LMI_CCITT_CISCO_LENGTH;
	int stat_len = (lmi == LMI_CISCO) ? 6 : 3;
	u8 *data;
	int i = 0;

	if (dce && fullrep) {
		len += state(hdlc)->dce_pvc_count * (2 + stat_len);
		if (len > HDLC_MAX_MRU) {
			netdev_warn(dev, "Too many PVCs while sending LMI full report\n");
			return;
		}
	}

	skb = dev_alloc_skb(len);
	if (!skb)
		return;

	memset(skb->data, 0, len);
	skb_reserve(skb, 4);
	if (lmi == LMI_CISCO)
		fr_hard_header(skb, LMI_CISCO_DLCI);
	else
		fr_hard_header(skb, LMI_CCITT_ANSI_DLCI);

	data = skb_tail_pointer(skb);
	data[i++] = LMI_CALLREF;
	data[i++] = dce ? LMI_STATUS : LMI_STATUS_ENQUIRY;
	if (lmi == LMI_ANSI)
		data[i++] = LMI_ANSI_LOCKSHIFT;
	data[i++] = lmi == LMI_CCITT ? LMI_CCITT_REPTYPE :
		LMI_ANSI_CISCO_REPTYPE;
	data[i++] = LMI_REPT_LEN;
	data[i++] = fullrep ? LMI_FULLREP : LMI_INTEGRITY;
	data[i++] = lmi == LMI_CCITT ? LMI_CCITT_ALIVE : LMI_ANSI_CISCO_ALIVE;
	data[i++] = LMI_INTEG_LEN;
	data[i++] = state(hdlc)->txseq =
		fr_lmi_nextseq(state(hdlc)->txseq);
	data[i++] = state(hdlc)->rxseq;

	if (dce && fullrep) {
		while (pvc) {
			data[i++] = lmi == LMI_CCITT ? LMI_CCITT_PVCSTAT :
				LMI_ANSI_CISCO_PVCSTAT;
			data[i++] = stat_len;

			/* LMI start/restart */
			if (state(hdlc)->reliable && !pvc->state.exist) {
				pvc->state.exist = pvc->state.new = 1;
				fr_log_dlci_active(pvc);
			}

			/* ifconfig PVC up */
			if (pvc->open_count && !pvc->state.active &&
			    pvc->state.exist && !pvc->state.new) {
				pvc_carrier(1, pvc);
				pvc->state.active = 1;
				fr_log_dlci_active(pvc);
			}

			if (lmi == LMI_CISCO) {
				data[i] = pvc->dlci >> 8;
				data[i + 1] = pvc->dlci & 0xFF;
			} else {
				data[i] = (pvc->dlci >> 4) & 0x3F;
				data[i + 1] = ((pvc->dlci << 3) & 0x78) | 0x80;
				data[i + 2] = 0x80;
			}

			if (pvc->state.new)
				data[i + 2] |= 0x08;
			else if (pvc->state.active)
				data[i + 2] |= 0x02;

			i += stat_len;
			pvc = pvc->next;
		}
	}

	skb_put(skb, i);
	skb->priority = TC_PRIO_CONTROL;
	skb->dev = dev;
	skb->protocol = htons(ETH_P_HDLC);
	skb_reset_network_header(skb);

	dev_queue_xmit(skb);
}

static void fr_set_link_state(int reliable, struct net_device *dev)
{
	hdlc_device *hdlc = dev_to_hdlc(dev);
	struct pvc_device *pvc = state(hdlc)->first_pvc;

	state(hdlc)->reliable = reliable;
	if (reliable) {
		netif_dormant_off(dev);
		state(hdlc)->n391cnt = 0; /* Request full status */
		state(hdlc)->dce_changed = 1;

		if (state(hdlc)->settings.lmi == LMI_NONE) {
			while (pvc) {	/* Activate all PVCs */
				pvc_carrier(1, pvc);
				pvc->state.exist = pvc->state.active = 1;
				pvc->state.new = 0;
				pvc = pvc->next;
			}
		}
	} else {
		netif_dormant_on(dev);
		while (pvc) {		/* Deactivate all PVCs */
			pvc_carrier(0, pvc);
			pvc->state.exist = pvc->state.active = 0;
			pvc->state.new = 0;
			if (!state(hdlc)->settings.dce)
				pvc->state.bandwidth = 0;
			pvc = pvc->next;
		}
	}
}

static void fr_timer(struct timer_list *t)
{
	struct frad_state *st = from_timer(st, t, timer);
	struct net_device *dev = st->dev;
	hdlc_device *hdlc = dev_to_hdlc(dev);
	int i, cnt = 0, reliable;
	u32 list;

	if (state(hdlc)->settings.dce) {
		reliable = state(hdlc)->request &&
			time_before(jiffies, state(hdlc)->last_poll +
				    state(hdlc)->settings.t392 * HZ);
		state(hdlc)->request = 0;
	} else {
		state(hdlc)->last_errors <<= 1; /* Shift the list */
		if (state(hdlc)->request) {
			if (state(hdlc)->reliable)
				netdev_info(dev, "No LMI status reply received\n");
			state(hdlc)->last_errors |= 1;
		}

		list = state(hdlc)->last_errors;
		for (i = 0; i < state(hdlc)->settings.n393; i++, list >>= 1)
			cnt += (list & 1);	/* errors count */

		reliable = (cnt < state(hdlc)->settings.n392);
	}

	if (state(hdlc)->reliable != reliable) {
		netdev_info(dev, "Link %sreliable\n", reliable ? "" : "un");
		fr_set_link_state(reliable, dev);
	}

	if (state(hdlc)->settings.dce) {
		state(hdlc)->timer.expires = jiffies +
			state(hdlc)->settings.t392 * HZ;
	} else {
		if (state(hdlc)->n391cnt)
			state(hdlc)->n391cnt--;

		fr_lmi_send(dev, state(hdlc)->n391cnt == 0);

		state(hdlc)->last_poll = jiffies;
		state(hdlc)->request = 1;
		state(hdlc)->timer.expires = jiffies +
			state(hdlc)->settings.t391 * HZ;
	}

	add_timer(&state(hdlc)->timer);
}

static int fr_lmi_recv(struct net_device *dev, struct sk_buff *skb)
{
	hdlc_device *hdlc = dev_to_hdlc(dev);
	struct pvc_device *pvc;
	u8 rxseq, txseq;
	int lmi = state(hdlc)->settings.lmi;
	int dce = state(hdlc)->settings.dce;
	int stat_len = (lmi == LMI_CISCO) ? 6 : 3, reptype, error, no_ram, i;

	if (skb->len < (lmi == LMI_ANSI ? LMI_ANSI_LENGTH :
			LMI_CCITT_CISCO_LENGTH)) {
		netdev_info(dev, "Short LMI frame\n");
		return 1;
	}

	if (skb->data[3] != (lmi == LMI_CISCO ? NLPID_CISCO_LMI :
			     NLPID_CCITT_ANSI_LMI)) {
		netdev_info(dev, "Received non-LMI frame with LMI DLCI\n");
		return 1;
	}

	if (skb->data[4] != LMI_CALLREF) {
		netdev_info(dev, "Invalid LMI Call reference (0x%02X)\n",
			    skb->data[4]);
		return 1;
	}

	if (skb->data[5] != (dce ? LMI_STATUS_ENQUIRY : LMI_STATUS)) {
		netdev_info(dev, "Invalid LMI Message type (0x%02X)\n",
			    skb->data[5]);
		return 1;
	}

	if (lmi == LMI_ANSI) {
		if (skb->data[6] != LMI_ANSI_LOCKSHIFT) {
			netdev_info(dev, "Not ANSI locking shift in LMI message (0x%02X)\n",
				    skb->data[6]);
			return 1;
		}
		i = 7;
	} else {
		i = 6;
	}

	if (skb->data[i] != (lmi == LMI_CCITT ? LMI_CCITT_REPTYPE :
			     LMI_ANSI_CISCO_REPTYPE)) {
		netdev_info(dev, "Not an LMI Report type IE (0x%02X)\n",
			    skb->data[i]);
		return 1;
	}

	if (skb->data[++i] != LMI_REPT_LEN) {
		netdev_info(dev, "Invalid LMI Report type IE length (%u)\n",
			    skb->data[i]);
		return 1;
	}

	reptype = skb->data[++i];
	if (reptype != LMI_INTEGRITY && reptype != LMI_FULLREP) {
		netdev_info(dev, "Unsupported LMI Report type (0x%02X)\n",
			    reptype);
		return 1;
	}

	if (skb->data[++i] != (lmi == LMI_CCITT ? LMI_CCITT_ALIVE :
			       LMI_ANSI_CISCO_ALIVE)) {
		netdev_info(dev, "Not an LMI Link integrity verification IE (0x%02X)\n",
			    skb->data[i]);
		return 1;
	}

	if (skb->data[++i] != LMI_INTEG_LEN) {
		netdev_info(dev, "Invalid LMI Link integrity verification IE length (%u)\n",
			    skb->data[i]);
		return 1;
	}
	i++;

	state(hdlc)->rxseq = skb->data[i++]; /* TX sequence from peer */
	rxseq = skb->data[i++];	/* Should confirm our sequence */

	txseq = state(hdlc)->txseq;

	if (dce)
		state(hdlc)->last_poll = jiffies;

	error = 0;
	if (!state(hdlc)->reliable)
		error = 1;

	if (rxseq == 0 || rxseq != txseq) { /* Ask for full report next time */
		state(hdlc)->n391cnt = 0;
		error = 1;
	}

	if (dce) {
		if (state(hdlc)->fullrep_sent && !error) {
/* Stop sending full report - the last one has been confirmed by DTE */
			state(hdlc)->fullrep_sent = 0;
			pvc = state(hdlc)->first_pvc;
			while (pvc) {
				if (pvc->state.new) {
					pvc->state.new = 0;

/* Tell DTE that new PVC is now active */
					state(hdlc)->dce_changed = 1;
				}
				pvc = pvc->next;
			}
		}

		if (state(hdlc)->dce_changed) {
			reptype = LMI_FULLREP;
			state(hdlc)->fullrep_sent = 1;
			state(hdlc)->dce_changed = 0;
		}

		state(hdlc)->request = 1; /* got request */
		fr_lmi_send(dev, reptype == LMI_FULLREP ? 1 : 0);
		return 0;
	}

	/* DTE */

	state(hdlc)->request = 0; /* got response, no request pending */

	if (error)
		return 0;

	if (reptype != LMI_FULLREP)
		return 0;

	pvc = state(hdlc)->first_pvc;

	while (pvc) {
		pvc->state.deleted = 1;
		pvc = pvc->next;
	}

	no_ram = 0;
	while (skb->len >= i + 2 + stat_len) {
		u16 dlci;
		u32 bw;
		unsigned int active, new;

		if (skb->data[i] != (lmi == LMI_CCITT ? LMI_CCITT_PVCSTAT :
				       LMI_ANSI_CISCO_PVCSTAT)) {
			netdev_info(dev, "Not an LMI PVC status IE (0x%02X)\n",
				    skb->data[i]);
			return 1;
		}

		if (skb->data[++i] != stat_len) {
			netdev_info(dev, "Invalid LMI PVC status IE length (%u)\n",
				    skb->data[i]);
			return 1;
		}
		i++;

		new = !!(skb->data[i + 2] & 0x08);
		active = !!(skb->data[i + 2] & 0x02);
		if (lmi == LMI_CISCO) {
			dlci = (skb->data[i] << 8) | skb->data[i + 1];
			bw = (skb->data[i + 3] << 16) |
				(skb->data[i + 4] << 8) |
				(skb->data[i + 5]);
		} else {
			dlci = ((skb->data[i] & 0x3F) << 4) |
				((skb->data[i + 1] & 0x78) >> 3);
			bw = 0;
		}

		pvc = add_pvc(dev, dlci);

		if (!pvc && !no_ram) {
			netdev_warn(dev, "Memory squeeze on fr_lmi_recv()\n");
			no_ram = 1;
		}

		if (pvc) {
			pvc->state.exist = 1;
			pvc->state.deleted = 0;
			if (active != pvc->state.active ||
			    new != pvc->state.new ||
			    bw != pvc->state.bandwidth ||
			    !pvc->state.exist) {
				pvc->state.new = new;
				pvc->state.active = active;
				pvc->state.bandwidth = bw;
				pvc_carrier(active, pvc);
				fr_log_dlci_active(pvc);
			}
		}

		i += stat_len;
	}

	pvc = state(hdlc)->first_pvc;

	while (pvc) {
		if (pvc->state.deleted && pvc->state.exist) {
			pvc_carrier(0, pvc);
			pvc->state.active = pvc->state.new = 0;
			pvc->state.exist = 0;
			pvc->state.bandwidth = 0;
			fr_log_dlci_active(pvc);
		}
		pvc = pvc->next;
	}

	/* Next full report after N391 polls */
	state(hdlc)->n391cnt = state(hdlc)->settings.n391;

	return 0;
}

static int fr_snap_parse(struct sk_buff *skb, struct pvc_device *pvc)
{
	/* OUI 00-00-00 indicates an Ethertype follows */
	if (skb->data[0] == 0x00 &&
	    skb->data[1] == 0x00 &&
	    skb->data[2] == 0x00) {
		if (!pvc->main)
			return -1;
		skb->dev = pvc->main;
		skb->protocol = *(__be16 *)(skb->data + 3); /* Ethertype */
		skb_pull(skb, 5);
		skb_reset_mac_header(skb);
		return 0;

	/* OUI 00-80-C2 stands for the 802.1 organization */
	} else if (skb->data[0] == 0x00 &&
		   skb->data[1] == 0x80 &&
		   skb->data[2] == 0xC2) {
		/* PID 00-07 stands for Ethernet frames without FCS */
		if (skb->data[3] == 0x00 &&
		    skb->data[4] == 0x07) {
			if (!pvc->ether)
				return -1;
			skb_pull(skb, 5);
			if (skb->len < ETH_HLEN)
				return -1;
			skb->protocol = eth_type_trans(skb, pvc->ether);
			return 0;

		/* PID unsupported */
		} else {
			return -1;
		}

	/* OUI unsupported */
	} else {
		return -1;
	}
}

static int fr_rx(struct sk_buff *skb)
{
	struct net_device *frad = skb->dev;
	hdlc_device *hdlc = dev_to_hdlc(frad);
	struct fr_hdr *fh = (struct fr_hdr *)skb->data;
	u8 *data = skb->data;
	u16 dlci;
	struct pvc_device *pvc;
	struct net_device *dev;

	if (skb->len < 4 || fh->ea1 || !fh->ea2 || data[2] != FR_UI)
		goto rx_error;

	dlci = q922_to_dlci(skb->data);

	if ((dlci == LMI_CCITT_ANSI_DLCI &&
	     (state(hdlc)->settings.lmi == LMI_ANSI ||
	      state(hdlc)->settings.lmi == LMI_CCITT)) ||
	    (dlci == LMI_CISCO_DLCI &&
	     state(hdlc)->settings.lmi == LMI_CISCO)) {
		if (fr_lmi_recv(frad, skb))
			goto rx_error;
		dev_kfree_skb_any(skb);
		return NET_RX_SUCCESS;
	}

	pvc = find_pvc(hdlc, dlci);
	if (!pvc) {
#ifdef DEBUG_PKT
		netdev_info(frad, "No PVC for received frame's DLCI %d\n",
			    dlci);
#endif
		goto rx_drop;
	}

	if (pvc->state.fecn != fh->fecn) {
#ifdef DEBUG_ECN
		printk(KERN_DEBUG "%s: DLCI %d FECN O%s\n", frad->name,
		       dlci, fh->fecn ? "N" : "FF");
#endif
		pvc->state.fecn ^= 1;
	}

	if (pvc->state.becn != fh->becn) {
#ifdef DEBUG_ECN
		printk(KERN_DEBUG "%s: DLCI %d BECN O%s\n", frad->name,
		       dlci, fh->becn ? "N" : "FF");
#endif
		pvc->state.becn ^= 1;
	}

	skb = skb_share_check(skb, GFP_ATOMIC);
	if (!skb) {
		frad->stats.rx_dropped++;
		return NET_RX_DROP;
	}

	if (data[3] == NLPID_IP) {
		if (!pvc->main)
			goto rx_drop;
		skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */
		skb->dev = pvc->main;
		skb->protocol = htons(ETH_P_IP);
		skb_reset_mac_header(skb);

	} else if (data[3] == NLPID_IPV6) {
		if (!pvc->main)
			goto rx_drop;
		skb_pull(skb, 4); /* Remove 4-byte header (hdr, UI, NLPID) */
		skb->dev = pvc->main;
		skb->protocol = htons(ETH_P_IPV6);
		skb_reset_mac_header(skb);

	} else if (data[3] == FR_PAD) {
		if (skb->len < 5)
			goto rx_error;
		if (data[4] == NLPID_SNAP) { /* A SNAP header follows */
			skb_pull(skb, 5);
			if (skb->len < 5) /* Incomplete SNAP header */
				goto rx_error;
			if (fr_snap_parse(skb, pvc))
				goto rx_drop;
		} else {
			goto rx_drop;
		}

	} else {
		netdev_info(frad, "Unsupported protocol, NLPID=%x length=%i\n",
			    data[3], skb->len);
		goto rx_drop;
	}

	dev = skb->dev;
	dev->stats.rx_packets++; /* PVC traffic */
	dev->stats.rx_bytes += skb->len;
	if (pvc->state.becn)
		dev->stats.rx_compressed++;
	netif_rx(skb);
	return NET_RX_SUCCESS;

rx_error:
	frad->stats.rx_errors++; /* Mark error */
rx_drop:
	dev_kfree_skb_any(skb);
	return NET_RX_DROP;
}

static void fr_start(struct net_device *dev)
{
	hdlc_device *hdlc = dev_to_hdlc(dev);
#ifdef DEBUG_LINK
	printk(KERN_DEBUG "fr_start\n");
#endif
	if (state(hdlc)->settings.lmi != LMI_NONE) {
		state(hdlc)->reliable = 0;
		state(hdlc)->dce_changed = 1;
		state(hdlc)->request = 0;
		state(hdlc)->fullrep_sent = 0;
		state(hdlc)->last_errors = 0xFFFFFFFF;
		state(hdlc)->n391cnt = 0;
		state(hdlc)->txseq = state(hdlc)->rxseq = 0;

		state(hdlc)->dev = dev;
		timer_setup(&state(hdlc)->timer, fr_timer, 0);
		/* First poll after 1 s */
		state(hdlc)->timer.expires = jiffies + HZ;
		add_timer(&state(hdlc)->timer);
	} else {
		fr_set_link_state(1, dev);
	}
}

static void fr_stop(struct net_device *dev)
{
	hdlc_device *hdlc = dev_to_hdlc(dev);
#ifdef DEBUG_LINK
	printk(KERN_DEBUG "fr_stop\n");
#endif
	if (state(hdlc)->settings.lmi != LMI_NONE)
		del_timer_sync(&state(hdlc)->timer);
	fr_set_link_state(0, dev);
}

static void fr_close(struct net_device *dev)
{
	hdlc_device *hdlc = dev_to_hdlc(dev);
	struct pvc_device *pvc = state(hdlc)->first_pvc;

	while (pvc) {		/* Shutdown all PVCs for this FRAD */
		if (pvc->main)
			dev_close(pvc->main);
		if (pvc->ether)
			dev_close(pvc->ether);
		pvc = pvc->next;
	}
}

static void pvc_setup(struct net_device *dev)
{
	dev->type = ARPHRD_DLCI;
	dev->flags = IFF_POINTOPOINT;
	dev->hard_header_len = 0;
	dev->addr_len = 2;
	netif_keep_dst(dev);
}

static const struct net_device_ops pvc_ops = {
	.ndo_open       = pvc_open,
	.ndo_stop       = pvc_close,
	.ndo_start_xmit = pvc_xmit,
	.ndo_do_ioctl   = pvc_ioctl,
};

static int fr_add_pvc(struct net_device *frad, unsigned int dlci, int type)
{
	hdlc_device *hdlc = dev_to_hdlc(frad);
	struct pvc_device *pvc;
	struct net_device *dev;
	int used;

	pvc = add_pvc(frad, dlci);
	if (!pvc) {
		netdev_warn(frad, "Memory squeeze on fr_add_pvc()\n");
		return -ENOBUFS;
	}

	if (*get_dev_p(pvc, type))
		return -EEXIST;

	used = pvc_is_used(pvc);

	if (type == ARPHRD_ETHER)
		dev = alloc_netdev(0, "pvceth%d", NET_NAME_UNKNOWN,
				   ether_setup);
	else
		dev = alloc_netdev(0, "pvc%d", NET_NAME_UNKNOWN, pvc_setup);

	if (!dev) {
		netdev_warn(frad, "Memory squeeze on fr_pvc()\n");
		delete_unused_pvcs(hdlc);
		return -ENOBUFS;
	}

	if (type == ARPHRD_ETHER) {
		dev->priv_flags &= ~IFF_TX_SKB_SHARING;
		eth_hw_addr_random(dev);
	} else {
		*(__be16 *)dev->dev_addr = htons(dlci);
		dlci_to_q922(dev->broadcast, dlci);
	}
	dev->netdev_ops = &pvc_ops;
	dev->mtu = HDLC_MAX_MTU;
	dev->min_mtu = 68;
	dev->max_mtu = HDLC_MAX_MTU;
	dev->needed_headroom = 10;
	dev->priv_flags |= IFF_NO_QUEUE;
	dev->ml_priv = pvc;

	if (register_netdevice(dev) != 0) {
		free_netdev(dev);
		delete_unused_pvcs(hdlc);
		return -EIO;
	}

	dev->needs_free_netdev = true;
	*get_dev_p(pvc, type) = dev;
	if (!used) {
		state(hdlc)->dce_changed = 1;
		state(hdlc)->dce_pvc_count++;
	}
	return 0;
}

static int fr_del_pvc(hdlc_device *hdlc, unsigned int dlci, int type)
{
	struct pvc_device *pvc;
	struct net_device *dev;

	pvc = find_pvc(hdlc, dlci);
	if (!pvc)
		return -ENOENT;

	dev = *get_dev_p(pvc, type);
	if (!dev)
		return -ENOENT;

	if (dev->flags & IFF_UP)
		return -EBUSY;		/* PVC in use */

	unregister_netdevice(dev); /* the destructor will free_netdev(dev) */
	*get_dev_p(pvc, type) = NULL;

	if (!pvc_is_used(pvc)) {
		state(hdlc)->dce_pvc_count--;
		state(hdlc)->dce_changed = 1;
	}
	delete_unused_pvcs(hdlc);
	return 0;
}

static void fr_destroy(struct net_device *frad)
{
	hdlc_device *hdlc = dev_to_hdlc(frad);
	struct pvc_device *pvc = state(hdlc)->first_pvc;

	state(hdlc)->first_pvc = NULL; /* All PVCs destroyed */
	state(hdlc)->dce_pvc_count = 0;
	state(hdlc)->dce_changed = 1;

	while (pvc) {
		struct pvc_device *next = pvc->next;
		/* destructors will free_netdev() main and ether */
		if (pvc->main)
			unregister_netdevice(pvc->main);

		if (pvc->ether)
			unregister_netdevice(pvc->ether);

		kfree(pvc);
		pvc = next;
	}
}

static struct hdlc_proto proto = {
	.close		= fr_close,
	.start		= fr_start,
	.stop		= fr_stop,
	.detach		= fr_destroy,
	.ioctl		= fr_ioctl,
	.netif_rx	= fr_rx,
	.module		= THIS_MODULE,
};

static int fr_ioctl(struct net_device *dev, struct ifreq *ifr)
{
	fr_proto __user *fr_s = ifr->ifr_settings.ifs_ifsu.fr;
	const size_t size = sizeof(fr_proto);
	fr_proto new_settings;
	hdlc_device *hdlc = dev_to_hdlc(dev);
	fr_proto_pvc pvc;
	int result;

	switch (ifr->ifr_settings.type) {
	case IF_GET_PROTO:
		if (dev_to_hdlc(dev)->proto != &proto) /* Different proto */
			return -EINVAL;
		ifr->ifr_settings.type = IF_PROTO_FR;
		if (ifr->ifr_settings.size < size) {
			ifr->ifr_settings.size = size; /* data size wanted */
			return -ENOBUFS;
		}
		if (copy_to_user(fr_s, &state(hdlc)->settings, size))
			return -EFAULT;
		return 0;

	case IF_PROTO_FR:
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

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

		if (copy_from_user(&new_settings, fr_s, size))
			return -EFAULT;

		if (new_settings.lmi == LMI_DEFAULT)
			new_settings.lmi = LMI_ANSI;

		if ((new_settings.lmi != LMI_NONE &&
		     new_settings.lmi != LMI_ANSI &&
		     new_settings.lmi != LMI_CCITT &&
		     new_settings.lmi != LMI_CISCO) ||
		    new_settings.t391 < 1 ||
		    new_settings.t392 < 2 ||
		    new_settings.n391 < 1 ||
		    new_settings.n392 < 1 ||
		    new_settings.n393 < new_settings.n392 ||
		    new_settings.n393 > 32 ||
		    (new_settings.dce != 0 &&
		     new_settings.dce != 1))
			return -EINVAL;

		result = hdlc->attach(dev, ENCODING_NRZ,
				      PARITY_CRC16_PR1_CCITT);
		if (result)
			return result;

		if (dev_to_hdlc(dev)->proto != &proto) { /* Different proto */
			result = attach_hdlc_protocol(dev, &proto,
						      sizeof(struct frad_state));
			if (result)
				return result;
			state(hdlc)->first_pvc = NULL;
			state(hdlc)->dce_pvc_count = 0;
		}
		memcpy(&state(hdlc)->settings, &new_settings, size);
		dev->type = ARPHRD_FRAD;
		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
		return 0;

	case IF_PROTO_FR_ADD_PVC:
	case IF_PROTO_FR_DEL_PVC:
	case IF_PROTO_FR_ADD_ETH_PVC:
	case IF_PROTO_FR_DEL_ETH_PVC:
		if (dev_to_hdlc(dev)->proto != &proto) /* Different proto */
			return -EINVAL;

		if (!capable(CAP_NET_ADMIN))
			return -EPERM;

		if (copy_from_user(&pvc, ifr->ifr_settings.ifs_ifsu.fr_pvc,
				   sizeof(fr_proto_pvc)))
			return -EFAULT;

		if (pvc.dlci <= 0 || pvc.dlci >= 1024)
			return -EINVAL;	/* Only 10 bits, DLCI 0 reserved */

		if (ifr->ifr_settings.type == IF_PROTO_FR_ADD_ETH_PVC ||
		    ifr->ifr_settings.type == IF_PROTO_FR_DEL_ETH_PVC)
			result = ARPHRD_ETHER; /* bridged Ethernet device */
		else
			result = ARPHRD_DLCI;

		if (ifr->ifr_settings.type == IF_PROTO_FR_ADD_PVC ||
		    ifr->ifr_settings.type == IF_PROTO_FR_ADD_ETH_PVC)
			return fr_add_pvc(dev, pvc.dlci, result);
		else
			return fr_del_pvc(hdlc, pvc.dlci, result);
	}

	return -EINVAL;
}

static int __init mod_init(void)
{
	register_hdlc_protocol(&proto);
	return 0;
}

static void __exit mod_exit(void)
{
	unregister_hdlc_protocol(&proto);
}

module_init(mod_init);
module_exit(mod_exit);

MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
MODULE_DESCRIPTION("Frame-Relay protocol support for generic HDLC");
MODULE_LICENSE("GPL v2");