aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/net/wan/syncppp.c
blob: c13b459a013789a62c1d7ade07739833791c9752 (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
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
/*
 *	NET3:	A (fairly minimal) implementation of synchronous PPP for Linux
 *		as well as a CISCO HDLC implementation. See the copyright 
 *		message below for the original source.
 *
 *	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.
 *
 *	Note however. This code is also used in a different form by FreeBSD.
 *	Therefore when making any non OS specific change please consider
 *	contributing it back to the original author under the terms
 *	below in addition.
 *		-- Alan
 *
 *	Port for Linux-2.1 by Jan "Yenya" Kasprzak <kas@fi.muni.cz>
 */

/*
 * Synchronous PPP/Cisco link level subroutines.
 * Keepalive protocol implemented in both Cisco and PPP modes.
 *
 * Copyright (C) 1994 Cronyx Ltd.
 * Author: Serge Vakulenko, <vak@zebub.msk.su>
 *
 * This software is distributed with NO WARRANTIES, not even the implied
 * warranties for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Authors grant any other persons or organisations permission to use
 * or modify this software as long as this message is kept with the software,
 * all derivative works or modified versions.
 *
 * Version 1.9, Wed Oct  4 18:58:15 MSK 1995
 *
 * $Id: syncppp.c,v 1.18 2000/04/11 05:25:31 asj Exp $
 */
#undef DEBUG

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/route.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/random.h>
#include <linux/pkt_sched.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>

#include <net/syncppp.h>

#include <asm/byteorder.h>
#include <asm/uaccess.h>

#define MAXALIVECNT     6               /* max. alive packets */

#define PPP_ALLSTATIONS 0xff            /* All-Stations broadcast address */
#define PPP_UI          0x03            /* Unnumbered Information */
#define PPP_IP          0x0021          /* Internet Protocol */
#define PPP_ISO         0x0023          /* ISO OSI Protocol */
#define PPP_XNS         0x0025          /* Xerox NS Protocol */
#define PPP_IPX         0x002b          /* Novell IPX Protocol */
#define PPP_LCP         0xc021          /* Link Control Protocol */
#define PPP_IPCP        0x8021          /* Internet Protocol Control Protocol */

#define LCP_CONF_REQ    1               /* PPP LCP configure request */
#define LCP_CONF_ACK    2               /* PPP LCP configure acknowledge */
#define LCP_CONF_NAK    3               /* PPP LCP configure negative ack */
#define LCP_CONF_REJ    4               /* PPP LCP configure reject */
#define LCP_TERM_REQ    5               /* PPP LCP terminate request */
#define LCP_TERM_ACK    6               /* PPP LCP terminate acknowledge */
#define LCP_CODE_REJ    7               /* PPP LCP code reject */
#define LCP_PROTO_REJ   8               /* PPP LCP protocol reject */
#define LCP_ECHO_REQ    9               /* PPP LCP echo request */
#define LCP_ECHO_REPLY  10              /* PPP LCP echo reply */
#define LCP_DISC_REQ    11              /* PPP LCP discard request */

#define LCP_OPT_MRU             1       /* maximum receive unit */
#define LCP_OPT_ASYNC_MAP       2       /* async control character map */
#define LCP_OPT_AUTH_PROTO      3       /* authentication protocol */
#define LCP_OPT_QUAL_PROTO      4       /* quality protocol */
#define LCP_OPT_MAGIC           5       /* magic number */
#define LCP_OPT_RESERVED        6       /* reserved */
#define LCP_OPT_PROTO_COMP      7       /* protocol field compression */
#define LCP_OPT_ADDR_COMP       8       /* address/control field compression */

#define IPCP_CONF_REQ   LCP_CONF_REQ    /* PPP IPCP configure request */
#define IPCP_CONF_ACK   LCP_CONF_ACK    /* PPP IPCP configure acknowledge */
#define IPCP_CONF_NAK   LCP_CONF_NAK    /* PPP IPCP configure negative ack */
#define IPCP_CONF_REJ   LCP_CONF_REJ    /* PPP IPCP configure reject */
#define IPCP_TERM_REQ   LCP_TERM_REQ    /* PPP IPCP terminate request */
#define IPCP_TERM_ACK   LCP_TERM_ACK    /* PPP IPCP terminate acknowledge */
#define IPCP_CODE_REJ   LCP_CODE_REJ    /* PPP IPCP code reject */

#define CISCO_MULTICAST         0x8f    /* Cisco multicast address */
#define CISCO_UNICAST           0x0f    /* Cisco unicast address */
#define CISCO_KEEPALIVE         0x8035  /* Cisco keepalive protocol */
#define CISCO_ADDR_REQ          0       /* Cisco address request */
#define CISCO_ADDR_REPLY        1       /* Cisco address reply */
#define CISCO_KEEPALIVE_REQ     2       /* Cisco keepalive request */

struct ppp_header {
	u8 address;
	u8 control;
	u16 protocol;
};
#define PPP_HEADER_LEN          sizeof (struct ppp_header)

struct lcp_header {
	u8 type;
	u8 ident;
	u16 len;
};
#define LCP_HEADER_LEN          sizeof (struct lcp_header)

struct cisco_packet {
	u32 type;
	u32 par1;
	u32 par2;
	u16 rel;
	u16 time0;
	u16 time1;
};
#define CISCO_PACKET_LEN 18
#define CISCO_BIG_PACKET_LEN 20

static struct sppp *spppq;
static struct timer_list sppp_keepalive_timer;
static DEFINE_SPINLOCK(spppq_lock);

/* global xmit queue for sending packets while spinlock is held */
static struct sk_buff_head tx_queue;

static void sppp_keepalive (unsigned long dummy);
static void sppp_cp_send (struct sppp *sp, u16 proto, u8 type,
	u8 ident, u16 len, void *data);
static void sppp_cisco_send (struct sppp *sp, int type, long par1, long par2);
static void sppp_lcp_input (struct sppp *sp, struct sk_buff *m);
static void sppp_cisco_input (struct sppp *sp, struct sk_buff *m);
static void sppp_ipcp_input (struct sppp *sp, struct sk_buff *m);
static void sppp_lcp_open (struct sppp *sp);
static void sppp_ipcp_open (struct sppp *sp);
static int sppp_lcp_conf_parse_options (struct sppp *sp, struct lcp_header *h,
	int len, u32 *magic);
static void sppp_cp_timeout (unsigned long arg);
static char *sppp_lcp_type_name (u8 type);
static char *sppp_ipcp_type_name (u8 type);
static void sppp_print_bytes (u8 *p, u16 len);

static int debug;

/* Flush global outgoing packet queue to dev_queue_xmit().
 *
 * dev_queue_xmit() must be called with interrupts enabled
 * which means it can't be called with spinlocks held.
 * If a packet needs to be sent while a spinlock is held,
 * then put the packet into tx_queue, and call sppp_flush_xmit()
 * after spinlock is released.
 */
static void sppp_flush_xmit(void)
{
	struct sk_buff *skb;
	while ((skb = skb_dequeue(&tx_queue)) != NULL)
		dev_queue_xmit(skb);
}

/*
 *	Interface down stub
 */	

static void if_down(struct net_device *dev)
{
	struct sppp *sp = (struct sppp *)sppp_of(dev);

	sp->pp_link_state=SPPP_LINK_DOWN;
}

/*
 * Timeout routine activations.
 */

static void sppp_set_timeout(struct sppp *p,int s) 
{
	if (! (p->pp_flags & PP_TIMO)) 
	{
		init_timer(&p->pp_timer);
		p->pp_timer.function=sppp_cp_timeout;
		p->pp_timer.expires=jiffies+s*HZ;
		p->pp_timer.data=(unsigned long)p;
		p->pp_flags |= PP_TIMO;
		add_timer(&p->pp_timer);
	}
}

static void sppp_clear_timeout(struct sppp *p)
{
	if (p->pp_flags & PP_TIMO) 
	{
		del_timer(&p->pp_timer);
		p->pp_flags &= ~PP_TIMO; 
	}
}

/**
 *	sppp_input -	receive and process a WAN PPP frame
 *	@skb:	The buffer to process
 *	@dev:	The device it arrived on
 *
 *	This can be called directly by cards that do not have
 *	timing constraints but is normally called from the network layer
 *	after interrupt servicing to process frames queued via netif_rx().
 *
 *	We process the options in the card. If the frame is destined for
 *	the protocol stacks then it requeues the frame for the upper level
 *	protocol. If it is a control from it is processed and discarded
 *	here.
 */
 
static void sppp_input (struct net_device *dev, struct sk_buff *skb)
{
	struct ppp_header *h;
	struct sppp *sp = (struct sppp *)sppp_of(dev);
	unsigned long flags;

	skb->dev=dev;
	skb->mac.raw=skb->data;

	if (dev->flags & IFF_RUNNING)
	{
		/* Count received bytes, add FCS and one flag */
		sp->ibytes+= skb->len + 3;
		sp->ipkts++;
	}

	if (!pskb_may_pull(skb, PPP_HEADER_LEN)) {
		/* Too small packet, drop it. */
		if (sp->pp_flags & PP_DEBUG)
			printk (KERN_DEBUG "%s: input packet is too small, %d bytes\n",
				dev->name, skb->len);
		kfree_skb(skb);
		return;
	}

	/* Get PPP header. */
	h = (struct ppp_header *)skb->data;
	skb_pull(skb,sizeof(struct ppp_header));

	spin_lock_irqsave(&sp->lock, flags);
	
	switch (h->address) {
	default:        /* Invalid PPP packet. */
		goto invalid;
	case PPP_ALLSTATIONS:
		if (h->control != PPP_UI)
			goto invalid;
		if (sp->pp_flags & PP_CISCO) {
			if (sp->pp_flags & PP_DEBUG)
				printk (KERN_WARNING "%s: PPP packet in Cisco mode <0x%x 0x%x 0x%x>\n",
					dev->name,
					h->address, h->control, ntohs (h->protocol));
			goto drop;
		}
		switch (ntohs (h->protocol)) {
		default:
			if (sp->lcp.state == LCP_STATE_OPENED)
				sppp_cp_send (sp, PPP_LCP, LCP_PROTO_REJ,
					++sp->pp_seq, skb->len + 2,
					&h->protocol);
			if (sp->pp_flags & PP_DEBUG)
				printk (KERN_WARNING "%s: invalid input protocol <0x%x 0x%x 0x%x>\n",
					dev->name,
					h->address, h->control, ntohs (h->protocol));
			goto drop;
		case PPP_LCP:
			sppp_lcp_input (sp, skb);
			goto drop;
		case PPP_IPCP:
			if (sp->lcp.state == LCP_STATE_OPENED)
				sppp_ipcp_input (sp, skb);
			else
				printk(KERN_DEBUG "IPCP when still waiting LCP finish.\n");
			goto drop;
		case PPP_IP:
			if (sp->ipcp.state == IPCP_STATE_OPENED) {
				if(sp->pp_flags&PP_DEBUG)
					printk(KERN_DEBUG "Yow an IP frame.\n");
				skb->protocol=htons(ETH_P_IP);
				netif_rx(skb);
				dev->last_rx = jiffies;
				goto done;
			}
			break;
#ifdef IPX
		case PPP_IPX:
			/* IPX IPXCP not implemented yet */
			if (sp->lcp.state == LCP_STATE_OPENED) {
				skb->protocol=htons(ETH_P_IPX);
				netif_rx(skb);
				dev->last_rx = jiffies;
				goto done;
			}
			break;
#endif
		}
		break;
	case CISCO_MULTICAST:
	case CISCO_UNICAST:
		/* Don't check the control field here (RFC 1547). */
		if (! (sp->pp_flags & PP_CISCO)) {
			if (sp->pp_flags & PP_DEBUG)
				printk (KERN_WARNING "%s: Cisco packet in PPP mode <0x%x 0x%x 0x%x>\n",
					dev->name,
					h->address, h->control, ntohs (h->protocol));
			goto drop;
		}
		switch (ntohs (h->protocol)) {
		default:
			goto invalid;
		case CISCO_KEEPALIVE:
			sppp_cisco_input (sp, skb);
			goto drop;
#ifdef CONFIG_INET
		case ETH_P_IP:
			skb->protocol=htons(ETH_P_IP);
			netif_rx(skb);
			dev->last_rx = jiffies;
			goto done;
#endif
#ifdef CONFIG_IPX
		case ETH_P_IPX:
			skb->protocol=htons(ETH_P_IPX);
			netif_rx(skb);
			dev->last_rx = jiffies;
			goto done;
#endif
		}
		break;
	}
	goto drop;

invalid:
	if (sp->pp_flags & PP_DEBUG)
		printk (KERN_WARNING "%s: invalid input packet <0x%x 0x%x 0x%x>\n",
			dev->name, h->address, h->control, ntohs (h->protocol));
drop:
	kfree_skb(skb);
done:
	spin_unlock_irqrestore(&sp->lock, flags);
	sppp_flush_xmit();
	return;
}

/*
 *	Handle transmit packets.
 */
 
static int sppp_hard_header(struct sk_buff *skb, struct net_device *dev, __u16 type,
		void *daddr, void *saddr, unsigned int len)
{
	struct sppp *sp = (struct sppp *)sppp_of(dev);
	struct ppp_header *h;
	skb_push(skb,sizeof(struct ppp_header));
	h=(struct ppp_header *)skb->data;
	if(sp->pp_flags&PP_CISCO)
	{
		h->address = CISCO_UNICAST;
		h->control = 0;
	}
	else
	{
		h->address = PPP_ALLSTATIONS;
		h->control = PPP_UI;
	}
	if(sp->pp_flags & PP_CISCO)
	{
		h->protocol = htons(type);
	}
	else switch(type)
	{
		case ETH_P_IP:
			h->protocol = htons(PPP_IP);
			break;
		case ETH_P_IPX:
			h->protocol = htons(PPP_IPX);
			break;
	}
	return sizeof(struct ppp_header);
}

static int sppp_rebuild_header(struct sk_buff *skb)
{
	return 0;
}

/*
 * Send keepalive packets, every 10 seconds.
 */

static void sppp_keepalive (unsigned long dummy)
{
	struct sppp *sp;
	unsigned long flags;

	spin_lock_irqsave(&spppq_lock, flags);

	for (sp=spppq; sp; sp=sp->pp_next) 
	{
		struct net_device *dev = sp->pp_if;

		/* Keepalive mode disabled or channel down? */
		if (! (sp->pp_flags & PP_KEEPALIVE) ||
		    ! (dev->flags & IFF_UP))
			continue;

		spin_lock(&sp->lock);

		/* No keepalive in PPP mode if LCP not opened yet. */
		if (! (sp->pp_flags & PP_CISCO) &&
		    sp->lcp.state != LCP_STATE_OPENED) {
			spin_unlock(&sp->lock);
			continue;
		}

		if (sp->pp_alivecnt == MAXALIVECNT) {
			/* No keepalive packets got.  Stop the interface. */
			printk (KERN_WARNING "%s: protocol down\n", dev->name);
			if_down (dev);
			if (! (sp->pp_flags & PP_CISCO)) {
				/* Shut down the PPP link. */
				sp->lcp.magic = jiffies;
				sp->lcp.state = LCP_STATE_CLOSED;
				sp->ipcp.state = IPCP_STATE_CLOSED;
				sppp_clear_timeout (sp);
				/* Initiate negotiation. */
				sppp_lcp_open (sp);
			}
		}
		if (sp->pp_alivecnt <= MAXALIVECNT)
			++sp->pp_alivecnt;
		if (sp->pp_flags & PP_CISCO)
			sppp_cisco_send (sp, CISCO_KEEPALIVE_REQ, ++sp->pp_seq,
				sp->pp_rseq);
		else if (sp->lcp.state == LCP_STATE_OPENED) {
			long nmagic = htonl (sp->lcp.magic);
			sp->lcp.echoid = ++sp->pp_seq;
			sppp_cp_send (sp, PPP_LCP, LCP_ECHO_REQ,
				sp->lcp.echoid, 4, &nmagic);
		}

		spin_unlock(&sp->lock);
	}
	spin_unlock_irqrestore(&spppq_lock, flags);
	sppp_flush_xmit();
	sppp_keepalive_timer.expires=jiffies+10*HZ;
	add_timer(&sppp_keepalive_timer);
}

/*
 * Handle incoming PPP Link Control Protocol packets.
 */
 
static void sppp_lcp_input (struct sppp *sp, struct sk_buff *skb)
{
	struct lcp_header *h;
	struct net_device *dev = sp->pp_if;
	int len = skb->len;
	u8 *p, opt[6];
	u32 rmagic;

	if (!pskb_may_pull(skb, sizeof(struct lcp_header))) {
		if (sp->pp_flags & PP_DEBUG)
			printk (KERN_WARNING "%s: invalid lcp packet length: %d bytes\n",
				dev->name, len);
		return;
	}
	h = (struct lcp_header *)skb->data;
	skb_pull(skb,sizeof(struct lcp_header *));
	
	if (sp->pp_flags & PP_DEBUG) 
	{
		char state = '?';
		switch (sp->lcp.state) {
		case LCP_STATE_CLOSED:   state = 'C'; break;
		case LCP_STATE_ACK_RCVD: state = 'R'; break;
		case LCP_STATE_ACK_SENT: state = 'S'; break;
		case LCP_STATE_OPENED:   state = 'O'; break;
		}
		printk (KERN_WARNING "%s: lcp input(%c): %d bytes <%s id=%xh len=%xh",
			dev->name, state, len,
			sppp_lcp_type_name (h->type), h->ident, ntohs (h->len));
		if (len > 4)
			sppp_print_bytes ((u8*) (h+1), len-4);
		printk (">\n");
	}
	if (len > ntohs (h->len))
		len = ntohs (h->len);
	switch (h->type) {
	default:
		/* Unknown packet type -- send Code-Reject packet. */
		sppp_cp_send (sp, PPP_LCP, LCP_CODE_REJ, ++sp->pp_seq,
			skb->len, h);
		break;
	case LCP_CONF_REQ:
		if (len < 4) {
			if (sp->pp_flags & PP_DEBUG)
				printk (KERN_DEBUG"%s: invalid lcp configure request packet length: %d bytes\n",
					dev->name, len);
			break;
		}
		if (len>4 && !sppp_lcp_conf_parse_options (sp, h, len, &rmagic))
			goto badreq;
		if (rmagic == sp->lcp.magic) {
			/* Local and remote magics equal -- loopback? */
			if (sp->pp_loopcnt >= MAXALIVECNT*5) {
				printk (KERN_WARNING "%s: loopback\n",
					dev->name);
				sp->pp_loopcnt = 0;
				if (dev->flags & IFF_UP) {
					if_down (dev);
				}
			} else if (sp->pp_flags & PP_DEBUG)
				printk (KERN_DEBUG "%s: conf req: magic glitch\n",
					dev->name);
			++sp->pp_loopcnt;

			/* MUST send Conf-Nack packet. */
			rmagic = ~sp->lcp.magic;
			opt[0] = LCP_OPT_MAGIC;
			opt[1] = sizeof (opt);
			opt[2] = rmagic >> 24;
			opt[3] = rmagic >> 16;
			opt[4] = rmagic >> 8;
			opt[5] = rmagic;
			sppp_cp_send (sp, PPP_LCP, LCP_CONF_NAK,
				h->ident, sizeof (opt), &opt);
badreq:
			switch (sp->lcp.state) {
			case LCP_STATE_OPENED:
				/* Initiate renegotiation. */
				sppp_lcp_open (sp);
				/* fall through... */
			case LCP_STATE_ACK_SENT:
				/* Go to closed state. */
				sp->lcp.state = LCP_STATE_CLOSED;
				sp->ipcp.state = IPCP_STATE_CLOSED;
			}
			break;
		}
		/* Send Configure-Ack packet. */
		sp->pp_loopcnt = 0;
		if (sp->lcp.state != LCP_STATE_OPENED) {
			sppp_cp_send (sp, PPP_LCP, LCP_CONF_ACK,
					h->ident, len-4, h+1);
		}
		/* Change the state. */
		switch (sp->lcp.state) {
		case LCP_STATE_CLOSED:
			sp->lcp.state = LCP_STATE_ACK_SENT;
			break;
		case LCP_STATE_ACK_RCVD:
			sp->lcp.state = LCP_STATE_OPENED;
			sppp_ipcp_open (sp);
			break;
		case LCP_STATE_OPENED:
			/* Remote magic changed -- close session. */
			sp->lcp.state = LCP_STATE_CLOSED;
			sp->ipcp.state = IPCP_STATE_CLOSED;
			/* Initiate renegotiation. */
			sppp_lcp_open (sp);
			/* Send ACK after our REQ in attempt to break loop */
			sppp_cp_send (sp, PPP_LCP, LCP_CONF_ACK,
					h->ident, len-4, h+1);
			sp->lcp.state = LCP_STATE_ACK_SENT;
			break;
		}
		break;
	case LCP_CONF_ACK:
		if (h->ident != sp->lcp.confid)
			break;
		sppp_clear_timeout (sp);
		if ((sp->pp_link_state != SPPP_LINK_UP) &&
		    (dev->flags & IFF_UP)) {
			/* Coming out of loopback mode. */
			sp->pp_link_state=SPPP_LINK_UP;
			printk (KERN_INFO "%s: protocol up\n", dev->name);
		}
		switch (sp->lcp.state) {
		case LCP_STATE_CLOSED:
			sp->lcp.state = LCP_STATE_ACK_RCVD;
			sppp_set_timeout (sp, 5);
			break;
		case LCP_STATE_ACK_SENT:
			sp->lcp.state = LCP_STATE_OPENED;
			sppp_ipcp_open (sp);
			break;
		}
		break;
	case LCP_CONF_NAK:
		if (h->ident != sp->lcp.confid)
			break;
		p = (u8*) (h+1);
		if (len>=10 && p[0] == LCP_OPT_MAGIC && p[1] >= 4) {
			rmagic = (u32)p[2] << 24 |
				(u32)p[3] << 16 | p[4] << 8 | p[5];
			if (rmagic == ~sp->lcp.magic) {
				int newmagic;
				if (sp->pp_flags & PP_DEBUG)
					printk (KERN_DEBUG "%s: conf nak: magic glitch\n",
						dev->name);
				get_random_bytes(&newmagic, sizeof(newmagic));
				sp->lcp.magic += newmagic;
			} else
				sp->lcp.magic = rmagic;
			}
		if (sp->lcp.state != LCP_STATE_ACK_SENT) {
			/* Go to closed state. */
			sp->lcp.state = LCP_STATE_CLOSED;
			sp->ipcp.state = IPCP_STATE_CLOSED;
		}
		/* The link will be renegotiated after timeout,
		 * to avoid endless req-nack loop. */
		sppp_clear_timeout (sp);
		sppp_set_timeout (sp, 2);
		break;
	case LCP_CONF_REJ:
		if (h->ident != sp->lcp.confid)
			break;
		sppp_clear_timeout (sp);
		/* Initiate renegotiation. */
		sppp_lcp_open (sp);
		if (sp->lcp.state != LCP_STATE_ACK_SENT) {
			/* Go to closed state. */
			sp->lcp.state = LCP_STATE_CLOSED;
			sp->ipcp.state = IPCP_STATE_CLOSED;
		}
		break;
	case LCP_TERM_REQ:
		sppp_clear_timeout (sp);
		/* Send Terminate-Ack packet. */
		sppp_cp_send (sp, PPP_LCP, LCP_TERM_ACK, h->ident, 0, NULL);
		/* Go to closed state. */
		sp->lcp.state = LCP_STATE_CLOSED;
		sp->ipcp.state = IPCP_STATE_CLOSED;
		/* Initiate renegotiation. */
		sppp_lcp_open (sp);
		break;
	case LCP_TERM_ACK:
	case LCP_CODE_REJ:
	case LCP_PROTO_REJ:
		/* Ignore for now. */
		break;
	case LCP_DISC_REQ:
		/* Discard the packet. */
		break;
	case LCP_ECHO_REQ:
		if (sp->lcp.state != LCP_STATE_OPENED)
			break;
		if (len < 8) {
			if (sp->pp_flags & PP_DEBUG)
				printk (KERN_WARNING "%s: invalid lcp echo request packet length: %d bytes\n",
					dev->name, len);
			break;
		}
		if (ntohl (*(long*)(h+1)) == sp->lcp.magic) {
			/* Line loopback mode detected. */
			printk (KERN_WARNING "%s: loopback\n", dev->name);
			if_down (dev);

			/* Shut down the PPP link. */
			sp->lcp.state = LCP_STATE_CLOSED;
			sp->ipcp.state = IPCP_STATE_CLOSED;
			sppp_clear_timeout (sp);
			/* Initiate negotiation. */
			sppp_lcp_open (sp);
			break;
		}
		*(long*)(h+1) = htonl (sp->lcp.magic);
		sppp_cp_send (sp, PPP_LCP, LCP_ECHO_REPLY, h->ident, len-4, h+1);
		break;
	case LCP_ECHO_REPLY:
		if (h->ident != sp->lcp.echoid)
			break;
		if (len < 8) {
			if (sp->pp_flags & PP_DEBUG)
				printk (KERN_WARNING "%s: invalid lcp echo reply packet length: %d bytes\n",
					dev->name, len);
			break;
		}
		if (ntohl (*(long*)(h+1)) != sp->lcp.magic)
		sp->pp_alivecnt = 0;
		break;
	}
}

/*
 * Handle incoming Cisco keepalive protocol packets.
 */

static void sppp_cisco_input (struct sppp *sp, struct sk_buff *skb)
{
	struct cisco_packet *h;
	struct net_device *dev = sp->pp_if;

	if (!pskb_may_pull(skb, sizeof(struct cisco_packet))
	    || (skb->len != CISCO_PACKET_LEN
		&& skb->len != CISCO_BIG_PACKET_LEN)) {
		if (sp->pp_flags & PP_DEBUG)
			printk (KERN_WARNING "%s: invalid cisco packet length: %d bytes\n",
				dev->name,  skb->len);
		return;
	}
	h = (struct cisco_packet *)skb->data;
	skb_pull(skb, sizeof(struct cisco_packet*));
	if (sp->pp_flags & PP_DEBUG)
		printk (KERN_WARNING "%s: cisco input: %d bytes <%xh %xh %xh %xh %xh-%xh>\n",
			dev->name,  skb->len,
			ntohl (h->type), h->par1, h->par2, h->rel,
			h->time0, h->time1);
	switch (ntohl (h->type)) {
	default:
		if (sp->pp_flags & PP_DEBUG)
			printk (KERN_WARNING "%s: unknown cisco packet type: 0x%x\n",
				dev->name,  ntohl (h->type));
		break;
	case CISCO_ADDR_REPLY:
		/* Reply on address request, ignore */
		break;
	case CISCO_KEEPALIVE_REQ:
		sp->pp_alivecnt = 0;
		sp->pp_rseq = ntohl (h->par1);
		if (sp->pp_seq == sp->pp_rseq) {
			/* Local and remote sequence numbers are equal.
			 * Probably, the line is in loopback mode. */
			int newseq;
			if (sp->pp_loopcnt >= MAXALIVECNT) {
				printk (KERN_WARNING "%s: loopback\n",
					dev->name);
				sp->pp_loopcnt = 0;
				if (dev->flags & IFF_UP) {
					if_down (dev);
				}
			}
			++sp->pp_loopcnt;

			/* Generate new local sequence number */
			get_random_bytes(&newseq, sizeof(newseq));
			sp->pp_seq ^= newseq;
			break;
		}
		sp->pp_loopcnt = 0;
		if (sp->pp_link_state==SPPP_LINK_DOWN &&
		    (dev->flags & IFF_UP)) {
			sp->pp_link_state=SPPP_LINK_UP;
			printk (KERN_INFO "%s: protocol up\n", dev->name);
		}
		break;
	case CISCO_ADDR_REQ:
		/* Stolen from net/ipv4/devinet.c -- SIOCGIFADDR ioctl */
		{
		struct in_device *in_dev;
		struct in_ifaddr *ifa;
		u32 addr = 0, mask = ~0; /* FIXME: is the mask correct? */
#ifdef CONFIG_INET
		rcu_read_lock();
		if ((in_dev = __in_dev_get_rcu(dev)) != NULL)
		{
			for (ifa=in_dev->ifa_list; ifa != NULL;
				ifa=ifa->ifa_next) {
				if (strcmp(dev->name, ifa->ifa_label) == 0) 
				{
					addr = ifa->ifa_local;
					mask = ifa->ifa_mask;
					break;
				}
			}
		}
		rcu_read_unlock();
#endif		
		/* I hope both addr and mask are in the net order */
		sppp_cisco_send (sp, CISCO_ADDR_REPLY, addr, mask);
		break;
		}
	}
}


/*
 * Send PPP LCP packet.
 */

static void sppp_cp_send (struct sppp *sp, u16 proto, u8 type,
	u8 ident, u16 len, void *data)
{
	struct ppp_header *h;
	struct lcp_header *lh;
	struct sk_buff *skb;
	struct net_device *dev = sp->pp_if;

	skb=alloc_skb(dev->hard_header_len+PPP_HEADER_LEN+LCP_HEADER_LEN+len,
		GFP_ATOMIC);
	if (skb==NULL)
		return;

	skb_reserve(skb,dev->hard_header_len);
	
	h = (struct ppp_header *)skb_put(skb, sizeof(struct ppp_header));
	h->address = PPP_ALLSTATIONS;        /* broadcast address */
	h->control = PPP_UI;                 /* Unnumbered Info */
	h->protocol = htons (proto);         /* Link Control Protocol */

	lh = (struct lcp_header *)skb_put(skb, sizeof(struct lcp_header));
	lh->type = type;
	lh->ident = ident;
	lh->len = htons (LCP_HEADER_LEN + len);

	if (len)
		memcpy(skb_put(skb,len),data, len);

	if (sp->pp_flags & PP_DEBUG) {
		printk (KERN_WARNING "%s: %s output <%s id=%xh len=%xh",
			dev->name, 
			proto==PPP_LCP ? "lcp" : "ipcp",
			proto==PPP_LCP ? sppp_lcp_type_name (lh->type) :
			sppp_ipcp_type_name (lh->type), lh->ident,
			ntohs (lh->len));
		if (len)
			sppp_print_bytes ((u8*) (lh+1), len);
		printk (">\n");
	}
	sp->obytes += skb->len;
	/* Control is high priority so it doesn't get queued behind data */
	skb->priority=TC_PRIO_CONTROL;
	skb->dev = dev;
	skb_queue_tail(&tx_queue, skb);
}

/*
 * Send Cisco keepalive packet.
 */

static void sppp_cisco_send (struct sppp *sp, int type, long par1, long par2)
{
	struct ppp_header *h;
	struct cisco_packet *ch;
	struct sk_buff *skb;
	struct net_device *dev = sp->pp_if;
	u32 t = jiffies * 1000/HZ;

	skb=alloc_skb(dev->hard_header_len+PPP_HEADER_LEN+CISCO_PACKET_LEN,
		GFP_ATOMIC);

	if(skb==NULL)
		return;
		
	skb_reserve(skb, dev->hard_header_len);
	h = (struct ppp_header *)skb_put (skb, sizeof(struct ppp_header));
	h->address = CISCO_MULTICAST;
	h->control = 0;
	h->protocol = htons (CISCO_KEEPALIVE);

	ch = (struct cisco_packet*)skb_put(skb, CISCO_PACKET_LEN);
	ch->type = htonl (type);
	ch->par1 = htonl (par1);
	ch->par2 = htonl (par2);
	ch->rel = -1;
	ch->time0 = htons ((u16) (t >> 16));
	ch->time1 = htons ((u16) t);

	if (sp->pp_flags & PP_DEBUG)
		printk (KERN_WARNING "%s: cisco output: <%xh %xh %xh %xh %xh-%xh>\n",
			dev->name,  ntohl (ch->type), ch->par1,
			ch->par2, ch->rel, ch->time0, ch->time1);
	sp->obytes += skb->len;
	skb->priority=TC_PRIO_CONTROL;
	skb->dev = dev;
	skb_queue_tail(&tx_queue, skb);
}

/**
 *	sppp_close - close down a synchronous PPP or Cisco HDLC link
 *	@dev: The network device to drop the link of
 *
 *	This drops the logical interface to the channel. It is not
 *	done politely as we assume we will also be dropping DTR. Any
 *	timeouts are killed.
 */

int sppp_close (struct net_device *dev)
{
	struct sppp *sp = (struct sppp *)sppp_of(dev);
	unsigned long flags;

	spin_lock_irqsave(&sp->lock, flags);
	sp->pp_link_state = SPPP_LINK_DOWN;
	sp->lcp.state = LCP_STATE_CLOSED;
	sp->ipcp.state = IPCP_STATE_CLOSED;
	sppp_clear_timeout (sp);
	spin_unlock_irqrestore(&sp->lock, flags);

	return 0;
}

EXPORT_SYMBOL(sppp_close);

/**
 *	sppp_open - open a synchronous PPP or Cisco HDLC link
 *	@dev:	Network device to activate
 *	
 *	Close down any existing synchronous session and commence
 *	from scratch. In the PPP case this means negotiating LCP/IPCP
 *	and friends, while for Cisco HDLC we simply need to start sending
 *	keepalives
 */

int sppp_open (struct net_device *dev)
{
	struct sppp *sp = (struct sppp *)sppp_of(dev);
	unsigned long flags;

	sppp_close(dev);

	spin_lock_irqsave(&sp->lock, flags);
	if (!(sp->pp_flags & PP_CISCO)) {
		sppp_lcp_open (sp);
	}
	sp->pp_link_state = SPPP_LINK_DOWN;
	spin_unlock_irqrestore(&sp->lock, flags);
	sppp_flush_xmit();

	return 0;
}

EXPORT_SYMBOL(sppp_open);

/**
 *	sppp_reopen - notify of physical link loss
 *	@dev: Device that lost the link
 *
 *	This function informs the synchronous protocol code that
 *	the underlying link died (for example a carrier drop on X.21)
 *
 *	We increment the magic numbers to ensure that if the other end
 *	failed to notice we will correctly start a new session. It happens
 *	do to the nature of telco circuits is that you can lose carrier on
 *	one endonly.
 *
 *	Having done this we go back to negotiating. This function may
 *	be called from an interrupt context.
 */
 
int sppp_reopen (struct net_device *dev)
{
	struct sppp *sp = (struct sppp *)sppp_of(dev);
	unsigned long flags;

	sppp_close(dev);

	spin_lock_irqsave(&sp->lock, flags);
	if (!(sp->pp_flags & PP_CISCO))
	{
		sp->lcp.magic = jiffies;
		++sp->pp_seq;
		sp->lcp.state = LCP_STATE_CLOSED;
		sp->ipcp.state = IPCP_STATE_CLOSED;
		/* Give it a moment for the line to settle then go */
		sppp_set_timeout (sp, 1);
	} 
	sp->pp_link_state=SPPP_LINK_DOWN;
	spin_unlock_irqrestore(&sp->lock, flags);

	return 0;
}

EXPORT_SYMBOL(sppp_reopen);

/**
 *	sppp_change_mtu - Change the link MTU
 *	@dev:	Device to change MTU on
 *	@new_mtu: New MTU
 *
 *	Change the MTU on the link. This can only be called with
 *	the link down. It returns an error if the link is up or
 *	the mtu is out of range.
 */
 
static int sppp_change_mtu(struct net_device *dev, int new_mtu)
{
	if(new_mtu<128||new_mtu>PPP_MTU||(dev->flags&IFF_UP))
		return -EINVAL;
	dev->mtu=new_mtu;
	return 0;
}

/**
 *	sppp_do_ioctl - Ioctl handler for ppp/hdlc
 *	@dev: Device subject to ioctl
 *	@ifr: Interface request block from the user
 *	@cmd: Command that is being issued
 *	
 *	This function handles the ioctls that may be issued by the user
 *	to control the settings of a PPP/HDLC link. It does both busy
 *	and security checks. This function is intended to be wrapped by
 *	callers who wish to add additional ioctl calls of their own.
 */
 
int sppp_do_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
	struct sppp *sp = (struct sppp *)sppp_of(dev);

	if(dev->flags&IFF_UP)
		return -EBUSY;
		
	if(!capable(CAP_NET_ADMIN))
		return -EPERM;
	
	switch(cmd)
	{
		case SPPPIOCCISCO:
			sp->pp_flags|=PP_CISCO;
			dev->type = ARPHRD_HDLC;
			break;
		case SPPPIOCPPP:
			sp->pp_flags&=~PP_CISCO;
			dev->type = ARPHRD_PPP;
			break;
		case SPPPIOCDEBUG:
			sp->pp_flags&=~PP_DEBUG;
			if(ifr->ifr_flags)
				sp->pp_flags|=PP_DEBUG;
			break;
		case SPPPIOCGFLAGS:
			if(copy_to_user(ifr->ifr_data, &sp->pp_flags, sizeof(sp->pp_flags)))
				return -EFAULT;
			break;
		case SPPPIOCSFLAGS:
			if(copy_from_user(&sp->pp_flags, ifr->ifr_data, sizeof(sp->pp_flags)))
				return -EFAULT;
			break;
		default:
			return -EINVAL;
	}
	return 0;
}

EXPORT_SYMBOL(sppp_do_ioctl);

/**
 *	sppp_attach - attach synchronous PPP/HDLC to a device
 *	@pd:	PPP device to initialise
 *
 *	This initialises the PPP/HDLC support on an interface. At the
 *	time of calling the dev element must point to the network device
 *	that this interface is attached to. The interface should not yet
 *	be registered. 
 */
 
void sppp_attach(struct ppp_device *pd)
{
	struct net_device *dev = pd->dev;
	struct sppp *sp = &pd->sppp;
	unsigned long flags;

	/* Make sure embedding is safe for sppp_of */
	BUG_ON(sppp_of(dev) != sp);

	spin_lock_irqsave(&spppq_lock, flags);
	/* Initialize keepalive handler. */
	if (! spppq)
	{
		init_timer(&sppp_keepalive_timer);
		sppp_keepalive_timer.expires=jiffies+10*HZ;
		sppp_keepalive_timer.function=sppp_keepalive;
		add_timer(&sppp_keepalive_timer);
	}
	/* Insert new entry into the keepalive list. */
	sp->pp_next = spppq;
	spppq = sp;
	spin_unlock_irqrestore(&spppq_lock, flags);

	sp->pp_loopcnt = 0;
	sp->pp_alivecnt = 0;
	sp->pp_seq = 0;
	sp->pp_rseq = 0;
	sp->pp_flags = PP_KEEPALIVE|PP_CISCO|debug;/*PP_DEBUG;*/
	sp->lcp.magic = 0;
	sp->lcp.state = LCP_STATE_CLOSED;
	sp->ipcp.state = IPCP_STATE_CLOSED;
	sp->pp_if = dev;
	spin_lock_init(&sp->lock);
	
	/* 
	 *	Device specific setup. All but interrupt handler and
	 *	hard_start_xmit.
	 */
	 
	dev->hard_header = sppp_hard_header;
	dev->rebuild_header = sppp_rebuild_header;
	dev->tx_queue_len = 10;
	dev->type = ARPHRD_HDLC;
	dev->addr_len = 0;
	dev->hard_header_len = sizeof(struct ppp_header);
	dev->mtu = PPP_MTU;
	/*
	 *	These 4 are callers but MUST also call sppp_ functions
	 */
	dev->do_ioctl = sppp_do_ioctl;
#if 0
	dev->get_stats = NULL;		/* Let the driver override these */
	dev->open = sppp_open;
	dev->stop = sppp_close;
#endif	
	dev->change_mtu = sppp_change_mtu;
	dev->hard_header_cache = NULL;
	dev->header_cache_update = NULL;
	dev->flags = IFF_MULTICAST|IFF_POINTOPOINT|IFF_NOARP;
}

EXPORT_SYMBOL(sppp_attach);

/**
 *	sppp_detach - release PPP resources from a device
 *	@dev:	Network device to release
 *
 *	Stop and free up any PPP/HDLC resources used by this
 *	interface. This must be called before the device is
 *	freed.
 */
 
void sppp_detach (struct net_device *dev)
{
	struct sppp **q, *p, *sp = (struct sppp *)sppp_of(dev);
	unsigned long flags;

	spin_lock_irqsave(&spppq_lock, flags);
	/* Remove the entry from the keepalive list. */
	for (q = &spppq; (p = *q); q = &p->pp_next)
		if (p == sp) {
			*q = p->pp_next;
			break;
		}

	/* Stop keepalive handler. */
	if (! spppq)
		del_timer(&sppp_keepalive_timer);
	sppp_clear_timeout (sp);
	spin_unlock_irqrestore(&spppq_lock, flags);
}

EXPORT_SYMBOL(sppp_detach);

/*
 * Analyze the LCP Configure-Request options list
 * for the presence of unknown options.
 * If the request contains unknown options, build and
 * send Configure-reject packet, containing only unknown options.
 */
static int
sppp_lcp_conf_parse_options (struct sppp *sp, struct lcp_header *h,
	int len, u32 *magic)
{
	u8 *buf, *r, *p;
	int rlen;

	len -= 4;
	buf = r = kmalloc (len, GFP_ATOMIC);
	if (! buf)
		return (0);

	p = (void*) (h+1);
	for (rlen=0; len>1 && p[1]; len-=p[1], p+=p[1]) {
		switch (*p) {
		case LCP_OPT_MAGIC:
			/* Magic number -- extract. */
			if (len >= 6 && p[1] == 6) {
				*magic = (u32)p[2] << 24 |
					(u32)p[3] << 16 | p[4] << 8 | p[5];
				continue;
			}
			break;
		case LCP_OPT_ASYNC_MAP:
			/* Async control character map -- check to be zero. */
			if (len >= 6 && p[1] == 6 && ! p[2] && ! p[3] &&
			    ! p[4] && ! p[5])
				continue;
			break;
		case LCP_OPT_MRU:
			/* Maximum receive unit -- always OK. */
			continue;
		default:
			/* Others not supported. */
			break;
		}
		/* Add the option to rejected list. */
		memcpy(r, p, p[1]);
		r += p[1];
		rlen += p[1];
	}
	if (rlen)
		sppp_cp_send (sp, PPP_LCP, LCP_CONF_REJ, h->ident, rlen, buf);
	kfree(buf);
	return (rlen == 0);
}

static void sppp_ipcp_input (struct sppp *sp, struct sk_buff *skb)
{
	struct lcp_header *h;
	struct net_device *dev = sp->pp_if;
	int len = skb->len;

	if (!pskb_may_pull(skb, sizeof(struct lcp_header))) {
		if (sp->pp_flags & PP_DEBUG)
			printk (KERN_WARNING "%s: invalid ipcp packet length: %d bytes\n",
				dev->name,  len);
		return;
	}
	h = (struct lcp_header *)skb->data;
	skb_pull(skb,sizeof(struct lcp_header));
	if (sp->pp_flags & PP_DEBUG) {
		printk (KERN_WARNING "%s: ipcp input: %d bytes <%s id=%xh len=%xh",
			dev->name,  len,
			sppp_ipcp_type_name (h->type), h->ident, ntohs (h->len));
		if (len > 4)
			sppp_print_bytes ((u8*) (h+1), len-4);
		printk (">\n");
	}
	if (len > ntohs (h->len))
		len = ntohs (h->len);
	switch (h->type) {
	default:
		/* Unknown packet type -- send Code-Reject packet. */
		sppp_cp_send (sp, PPP_IPCP, IPCP_CODE_REJ, ++sp->pp_seq, len, h);
		break;
	case IPCP_CONF_REQ:
		if (len < 4) {
			if (sp->pp_flags & PP_DEBUG)
				printk (KERN_WARNING "%s: invalid ipcp configure request packet length: %d bytes\n",
					dev->name, len);
			return;
		}
		if (len > 4) {
			sppp_cp_send (sp, PPP_IPCP, LCP_CONF_REJ, h->ident,
				len-4, h+1);

			switch (sp->ipcp.state) {
			case IPCP_STATE_OPENED:
				/* Initiate renegotiation. */
				sppp_ipcp_open (sp);
				/* fall through... */
			case IPCP_STATE_ACK_SENT:
				/* Go to closed state. */
				sp->ipcp.state = IPCP_STATE_CLOSED;
			}
		} else {
			/* Send Configure-Ack packet. */
			sppp_cp_send (sp, PPP_IPCP, IPCP_CONF_ACK, h->ident,
				0, NULL);
			/* Change the state. */
			if (sp->ipcp.state == IPCP_STATE_ACK_RCVD)
				sp->ipcp.state = IPCP_STATE_OPENED;
			else
				sp->ipcp.state = IPCP_STATE_ACK_SENT;
		}
		break;
	case IPCP_CONF_ACK:
		if (h->ident != sp->ipcp.confid)
			break;
		sppp_clear_timeout (sp);
		switch (sp->ipcp.state) {
		case IPCP_STATE_CLOSED:
			sp->ipcp.state = IPCP_STATE_ACK_RCVD;
			sppp_set_timeout (sp, 5);
			break;
		case IPCP_STATE_ACK_SENT:
			sp->ipcp.state = IPCP_STATE_OPENED;
			break;
		}
		break;
	case IPCP_CONF_NAK:
	case IPCP_CONF_REJ:
		if (h->ident != sp->ipcp.confid)
			break;
		sppp_clear_timeout (sp);
			/* Initiate renegotiation. */
		sppp_ipcp_open (sp);
		if (sp->ipcp.state != IPCP_STATE_ACK_SENT)
			/* Go to closed state. */
			sp->ipcp.state = IPCP_STATE_CLOSED;
		break;
	case IPCP_TERM_REQ:
		/* Send Terminate-Ack packet. */
		sppp_cp_send (sp, PPP_IPCP, IPCP_TERM_ACK, h->ident, 0, NULL);
		/* Go to closed state. */
		sp->ipcp.state = IPCP_STATE_CLOSED;
		/* Initiate renegotiation. */
		sppp_ipcp_open (sp);
		break;
	case IPCP_TERM_ACK:
		/* Ignore for now. */
	case IPCP_CODE_REJ:
		/* Ignore for now. */
		break;
	}
}

static void sppp_lcp_open (struct sppp *sp)
{
	char opt[6];

	if (! sp->lcp.magic)
		sp->lcp.magic = jiffies;
	opt[0] = LCP_OPT_MAGIC;
	opt[1] = sizeof (opt);
	opt[2] = sp->lcp.magic >> 24;
	opt[3] = sp->lcp.magic >> 16;
	opt[4] = sp->lcp.magic >> 8;
	opt[5] = sp->lcp.magic;
	sp->lcp.confid = ++sp->pp_seq;
	sppp_cp_send (sp, PPP_LCP, LCP_CONF_REQ, sp->lcp.confid,
		sizeof (opt), &opt);
	sppp_set_timeout (sp, 2);
}

static void sppp_ipcp_open (struct sppp *sp)
{
	sp->ipcp.confid = ++sp->pp_seq;
	sppp_cp_send (sp, PPP_IPCP, IPCP_CONF_REQ, sp->ipcp.confid, 0, NULL);
	sppp_set_timeout (sp, 2);
}

/*
 * Process PPP control protocol timeouts.
 */
 
static void sppp_cp_timeout (unsigned long arg)
{
	struct sppp *sp = (struct sppp*) arg;
	unsigned long flags;

	spin_lock_irqsave(&sp->lock, flags);

	sp->pp_flags &= ~PP_TIMO;
	if (! (sp->pp_if->flags & IFF_UP) || (sp->pp_flags & PP_CISCO)) {
		spin_unlock_irqrestore(&sp->lock, flags);
		return;
	}
	switch (sp->lcp.state) {
	case LCP_STATE_CLOSED:
		/* No ACK for Configure-Request, retry. */
		sppp_lcp_open (sp);
		break;
	case LCP_STATE_ACK_RCVD:
		/* ACK got, but no Configure-Request for peer, retry. */
		sppp_lcp_open (sp);
		sp->lcp.state = LCP_STATE_CLOSED;
		break;
	case LCP_STATE_ACK_SENT:
		/* ACK sent but no ACK for Configure-Request, retry. */
		sppp_lcp_open (sp);
		break;
	case LCP_STATE_OPENED:
		/* LCP is already OK, try IPCP. */
		switch (sp->ipcp.state) {
		case IPCP_STATE_CLOSED:
			/* No ACK for Configure-Request, retry. */
			sppp_ipcp_open (sp);
			break;
		case IPCP_STATE_ACK_RCVD:
			/* ACK got, but no Configure-Request for peer, retry. */
			sppp_ipcp_open (sp);
			sp->ipcp.state = IPCP_STATE_CLOSED;
			break;
		case IPCP_STATE_ACK_SENT:
			/* ACK sent but no ACK for Configure-Request, retry. */
			sppp_ipcp_open (sp);
			break;
		case IPCP_STATE_OPENED:
			/* IPCP is OK. */
			break;
		}
		break;
	}
	spin_unlock_irqrestore(&sp->lock, flags);
	sppp_flush_xmit();
}

static char *sppp_lcp_type_name (u8 type)
{
	static char buf [8];
	switch (type) {
	case LCP_CONF_REQ:   return ("conf-req");
	case LCP_CONF_ACK:   return ("conf-ack");
	case LCP_CONF_NAK:   return ("conf-nack");
	case LCP_CONF_REJ:   return ("conf-rej");
	case LCP_TERM_REQ:   return ("term-req");
	case LCP_TERM_ACK:   return ("term-ack");
	case LCP_CODE_REJ:   return ("code-rej");
	case LCP_PROTO_REJ:  return ("proto-rej");
	case LCP_ECHO_REQ:   return ("echo-req");
	case LCP_ECHO_REPLY: return ("echo-reply");
	case LCP_DISC_REQ:   return ("discard-req");
	}
	sprintf (buf, "%xh", type);
	return (buf);
}

static char *sppp_ipcp_type_name (u8 type)
{
	static char buf [8];
	switch (type) {
	case IPCP_CONF_REQ:   return ("conf-req");
	case IPCP_CONF_ACK:   return ("conf-ack");
	case IPCP_CONF_NAK:   return ("conf-nack");
	case IPCP_CONF_REJ:   return ("conf-rej");
	case IPCP_TERM_REQ:   return ("term-req");
	case IPCP_TERM_ACK:   return ("term-ack");
	case IPCP_CODE_REJ:   return ("code-rej");
	}
	sprintf (buf, "%xh", type);
	return (buf);
}

static void sppp_print_bytes (u_char *p, u16 len)
{
	printk (" %x", *p++);
	while (--len > 0)
		printk ("-%x", *p++);
}

/**
 *	sppp_rcv -	receive and process a WAN PPP frame
 *	@skb:	The buffer to process
 *	@dev:	The device it arrived on
 *	@p: Unused
 *	@orig_dev: Unused
 *
 *	Protocol glue. This drives the deferred processing mode the poorer
 *	cards use. This can be called directly by cards that do not have
 *	timing constraints but is normally called from the network layer
 *	after interrupt servicing to process frames queued via netif_rx.
 */

static int sppp_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *p, struct net_device *orig_dev)
{
	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
		return NET_RX_DROP;
	sppp_input(dev,skb);
	return 0;
}

static struct packet_type sppp_packet_type = {
	.type	= __constant_htons(ETH_P_WAN_PPP),
	.func	= sppp_rcv,
};

static char banner[] __initdata = 
	KERN_INFO "Cronyx Ltd, Synchronous PPP and CISCO HDLC (c) 1994\n"
	KERN_INFO "Linux port (c) 1998 Building Number Three Ltd & "
		  "Jan \"Yenya\" Kasprzak.\n";

static int __init sync_ppp_init(void)
{
	if(debug)
		debug=PP_DEBUG;
	printk(banner);
	skb_queue_head_init(&tx_queue);
	dev_add_pack(&sppp_packet_type);
	return 0;
}


static void __exit sync_ppp_cleanup(void)
{
	dev_remove_pack(&sppp_packet_type);
}

module_init(sync_ppp_init);
module_exit(sync_ppp_cleanup);
module_param(debug, int, 0);
MODULE_LICENSE("GPL");