aboutsummaryrefslogtreecommitdiff
path: root/net/llc/llc_c_ev.c
blob: d6627a80cb459b2e8ffaa19b6e387e2248272e02 (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
/*
 * llc_c_ev.c - Connection component state transition event qualifiers
 *
 * A 'state' consists of a number of possible event matching functions,
 * the actions associated with each being executed when that event is
 * matched; a 'state machine' accepts events in a serial fashion from an
 * event queue. Each event is passed to each successive event matching
 * function until a match is made (the event matching function returns
 * success, or '0') or the list of event matching functions is exhausted.
 * If a match is made, the actions associated with the event are executed
 * and the state is changed to that event's transition state. Before some
 * events are recognized, even after a match has been made, a certain
 * number of 'event qualifier' functions must also be executed. If these
 * all execute successfully, then the event is finally executed.
 *
 * These event functions must return 0 for success, to show a matched
 * event, of 1 if the event does not match. Event qualifier functions
 * must return a 0 for success or a non-zero for failure. Each function
 * is simply responsible for verifying one single thing and returning
 * either a success or failure.
 *
 * All of followed event functions are described in 802.2 LLC Protocol
 * standard document except two functions that we added that will explain
 * in their comments, at below.
 *
 * Copyright (c) 1997 by Procom Technology, Inc.
 * 		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 * This program can be redistributed or modified under the terms of the
 * GNU General Public License as published by the Free Software Foundation.
 * This program is distributed without any warranty or implied warranty
 * of merchantability or fitness for a particular purpose.
 *
 * See the GNU General Public License for more details.
 */
#include <linux/netdevice.h>
#include <net/llc_conn.h>
#include <net/llc_sap.h>
#include <net/sock.h>
#include <net/llc_c_ac.h>
#include <net/llc_c_ev.h>
#include <net/llc_pdu.h>

#if 1
#define dprintk(args...) printk(KERN_DEBUG args)
#else
#define dprintk(args...)
#endif

/**
 *	llc_util_ns_inside_rx_window - check if sequence number is in rx window
 *	@ns: sequence number of received pdu.
 *	@vr: sequence number which receiver expects to receive.
 *	@rw: receive window size of receiver.
 *
 *	Checks if sequence number of received PDU is in range of receive
 *	window. Returns 0 for success, 1 otherwise
 */
static u16 llc_util_ns_inside_rx_window(u8 ns, u8 vr, u8 rw)
{
	return !llc_circular_between(vr, ns,
				     (vr + rw - 1) % LLC_2_SEQ_NBR_MODULO);
}

/**
 *	llc_util_nr_inside_tx_window - check if sequence number is in tx window
 *	@sk: current connection.
 *	@nr: N(R) of received PDU.
 *
 *	This routine checks if N(R) of received PDU is in range of transmit
 *	window; on the other hand checks if received PDU acknowledges some
 *	outstanding PDUs that are in transmit window. Returns 0 for success, 1
 *	otherwise.
 */
static u16 llc_util_nr_inside_tx_window(struct sock *sk, u8 nr)
{
	u8 nr1, nr2;
	struct sk_buff *skb;
	struct llc_pdu_sn *pdu;
	struct llc_sock *llc = llc_sk(sk);
	int rc = 0;

	if (llc->dev->flags & IFF_LOOPBACK)
		goto out;
	rc = 1;
	if (skb_queue_empty(&llc->pdu_unack_q))
		goto out;
	skb = skb_peek(&llc->pdu_unack_q);
	pdu = llc_pdu_sn_hdr(skb);
	nr1 = LLC_I_GET_NS(pdu);
	skb = skb_peek_tail(&llc->pdu_unack_q);
	pdu = llc_pdu_sn_hdr(skb);
	nr2 = LLC_I_GET_NS(pdu);
	rc = !llc_circular_between(nr1, nr, (nr2 + 1) % LLC_2_SEQ_NBR_MODULO);
out:
	return rc;
}

int llc_conn_ev_conn_req(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->prim == LLC_CONN_PRIM &&
	       ev->prim_type == LLC_PRIM_TYPE_REQ ? 0 : 1;
}

int llc_conn_ev_data_req(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->prim == LLC_DATA_PRIM &&
	       ev->prim_type == LLC_PRIM_TYPE_REQ ? 0 : 1;
}

int llc_conn_ev_disc_req(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->prim == LLC_DISC_PRIM &&
	       ev->prim_type == LLC_PRIM_TYPE_REQ ? 0 : 1;
}

int llc_conn_ev_rst_req(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->prim == LLC_RESET_PRIM &&
	       ev->prim_type == LLC_PRIM_TYPE_REQ ? 0 : 1;
}

int llc_conn_ev_local_busy_detected(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->type == LLC_CONN_EV_TYPE_SIMPLE &&
	       ev->prim_type == LLC_CONN_EV_LOCAL_BUSY_DETECTED ? 0 : 1;
}

int llc_conn_ev_local_busy_cleared(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->type == LLC_CONN_EV_TYPE_SIMPLE &&
	       ev->prim_type == LLC_CONN_EV_LOCAL_BUSY_CLEARED ? 0 : 1;
}

int llc_conn_ev_rx_bad_pdu(struct sock *sk, struct sk_buff *skb)
{
	return 1;
}

int llc_conn_ev_rx_disc_cmd_pbit_set_x(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_U(pdu) &&
	       LLC_U_PDU_CMD(pdu) == LLC_2_PDU_CMD_DISC ? 0 : 1;
}

int llc_conn_ev_rx_dm_rsp_fbit_set_x(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_U(pdu) &&
	       LLC_U_PDU_RSP(pdu) == LLC_2_PDU_RSP_DM ? 0 : 1;
}

int llc_conn_ev_rx_frmr_rsp_fbit_set_x(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_U(pdu) &&
	       LLC_U_PDU_RSP(pdu) == LLC_2_PDU_RSP_FRMR ? 0 : 1;
}

int llc_conn_ev_rx_i_cmd_pbit_set_0(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return llc_conn_space(sk, skb) &&
	       LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
	       LLC_I_PF_IS_0(pdu) &&
	       LLC_I_GET_NS(pdu) == llc_sk(sk)->vR ? 0 : 1;
}

int llc_conn_ev_rx_i_cmd_pbit_set_1(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return llc_conn_space(sk, skb) &&
	       LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
	       LLC_I_PF_IS_1(pdu) &&
	       LLC_I_GET_NS(pdu) == llc_sk(sk)->vR ? 0 : 1;
}

int llc_conn_ev_rx_i_cmd_pbit_set_0_unexpd_ns(struct sock *sk,
					      struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
	const u8 vr = llc_sk(sk)->vR;
	const u8 ns = LLC_I_GET_NS(pdu);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
	       LLC_I_PF_IS_0(pdu) && ns != vr &&
	       !llc_util_ns_inside_rx_window(ns, vr, llc_sk(sk)->rw) ? 0 : 1;
}

int llc_conn_ev_rx_i_cmd_pbit_set_1_unexpd_ns(struct sock *sk,
					      struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
	const u8 vr = llc_sk(sk)->vR;
	const u8 ns = LLC_I_GET_NS(pdu);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
	       LLC_I_PF_IS_1(pdu) && ns != vr &&
	       !llc_util_ns_inside_rx_window(ns, vr, llc_sk(sk)->rw) ? 0 : 1;
}

int llc_conn_ev_rx_i_cmd_pbit_set_x_inval_ns(struct sock *sk,
					     struct sk_buff *skb)
{
	const struct llc_pdu_sn * pdu = llc_pdu_sn_hdr(skb);
	const u8 vr = llc_sk(sk)->vR;
	const u8 ns = LLC_I_GET_NS(pdu);
	const u16 rc = LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
		ns != vr &&
		 llc_util_ns_inside_rx_window(ns, vr, llc_sk(sk)->rw) ? 0 : 1;
	if (!rc)
		dprintk("%s: matched, state=%d, ns=%d, vr=%d\n",
			__func__, llc_sk(sk)->state, ns, vr);
	return rc;
}

int llc_conn_ev_rx_i_rsp_fbit_set_0(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return llc_conn_space(sk, skb) &&
	       LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
	       LLC_I_PF_IS_0(pdu) &&
	       LLC_I_GET_NS(pdu) == llc_sk(sk)->vR ? 0 : 1;
}

int llc_conn_ev_rx_i_rsp_fbit_set_1(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
	       LLC_I_PF_IS_1(pdu) &&
	       LLC_I_GET_NS(pdu) == llc_sk(sk)->vR ? 0 : 1;
}

int llc_conn_ev_rx_i_rsp_fbit_set_x(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return llc_conn_space(sk, skb) &&
	       LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
	       LLC_I_GET_NS(pdu) == llc_sk(sk)->vR ? 0 : 1;
}

int llc_conn_ev_rx_i_rsp_fbit_set_0_unexpd_ns(struct sock *sk,
					      struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
	const u8 vr = llc_sk(sk)->vR;
	const u8 ns = LLC_I_GET_NS(pdu);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
	       LLC_I_PF_IS_0(pdu) && ns != vr &&
	       !llc_util_ns_inside_rx_window(ns, vr, llc_sk(sk)->rw) ? 0 : 1;
}

int llc_conn_ev_rx_i_rsp_fbit_set_1_unexpd_ns(struct sock *sk,
					      struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
	const u8 vr = llc_sk(sk)->vR;
	const u8 ns = LLC_I_GET_NS(pdu);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
	       LLC_I_PF_IS_1(pdu) && ns != vr &&
	       !llc_util_ns_inside_rx_window(ns, vr, llc_sk(sk)->rw) ? 0 : 1;
}

int llc_conn_ev_rx_i_rsp_fbit_set_x_unexpd_ns(struct sock *sk,
					      struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
	const u8 vr = llc_sk(sk)->vR;
	const u8 ns = LLC_I_GET_NS(pdu);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_I(pdu) && ns != vr &&
	       !llc_util_ns_inside_rx_window(ns, vr, llc_sk(sk)->rw) ? 0 : 1;
}

int llc_conn_ev_rx_i_rsp_fbit_set_x_inval_ns(struct sock *sk,
					     struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
	const u8 vr = llc_sk(sk)->vR;
	const u8 ns = LLC_I_GET_NS(pdu);
	const u16 rc = LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_I(pdu) &&
		ns != vr &&
		 llc_util_ns_inside_rx_window(ns, vr, llc_sk(sk)->rw) ? 0 : 1;
	if (!rc)
		dprintk("%s: matched, state=%d, ns=%d, vr=%d\n",
			__func__, llc_sk(sk)->state, ns, vr);
	return rc;
}

int llc_conn_ev_rx_rej_cmd_pbit_set_0(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_0(pdu) &&
	       LLC_S_PDU_CMD(pdu) == LLC_2_PDU_CMD_REJ ? 0 : 1;
}

int llc_conn_ev_rx_rej_cmd_pbit_set_1(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_1(pdu) &&
	       LLC_S_PDU_CMD(pdu) == LLC_2_PDU_CMD_REJ ? 0 : 1;
}

int llc_conn_ev_rx_rej_rsp_fbit_set_0(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_0(pdu) &&
	       LLC_S_PDU_RSP(pdu) == LLC_2_PDU_RSP_REJ ? 0 : 1;
}

int llc_conn_ev_rx_rej_rsp_fbit_set_1(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_1(pdu) &&
	       LLC_S_PDU_RSP(pdu) == LLC_2_PDU_RSP_REJ ? 0 : 1;
}

int llc_conn_ev_rx_rej_rsp_fbit_set_x(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PDU_RSP(pdu) == LLC_2_PDU_RSP_REJ ? 0 : 1;
}

int llc_conn_ev_rx_rnr_cmd_pbit_set_0(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_0(pdu) &&
	       LLC_S_PDU_CMD(pdu) == LLC_2_PDU_CMD_RNR ? 0 : 1;
}

int llc_conn_ev_rx_rnr_cmd_pbit_set_1(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_1(pdu) &&
	       LLC_S_PDU_CMD(pdu) == LLC_2_PDU_CMD_RNR ? 0 : 1;
}

int llc_conn_ev_rx_rnr_rsp_fbit_set_0(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_0(pdu) &&
	       LLC_S_PDU_RSP(pdu) == LLC_2_PDU_RSP_RNR ? 0 : 1;
}

int llc_conn_ev_rx_rnr_rsp_fbit_set_1(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_1(pdu) &&
	       LLC_S_PDU_RSP(pdu) == LLC_2_PDU_RSP_RNR ? 0 : 1;
}

int llc_conn_ev_rx_rr_cmd_pbit_set_0(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_0(pdu) &&
	       LLC_S_PDU_CMD(pdu) == LLC_2_PDU_CMD_RR ? 0 : 1;
}

int llc_conn_ev_rx_rr_cmd_pbit_set_1(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_1(pdu) &&
	       LLC_S_PDU_CMD(pdu) == LLC_2_PDU_CMD_RR ? 0 : 1;
}

int llc_conn_ev_rx_rr_rsp_fbit_set_0(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return llc_conn_space(sk, skb) &&
	       LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_0(pdu) &&
	       LLC_S_PDU_RSP(pdu) == LLC_2_PDU_RSP_RR ? 0 : 1;
}

int llc_conn_ev_rx_rr_rsp_fbit_set_1(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	return llc_conn_space(sk, skb) &&
	       LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_S(pdu) &&
	       LLC_S_PF_IS_1(pdu) &&
	       LLC_S_PDU_RSP(pdu) == LLC_2_PDU_RSP_RR ? 0 : 1;
}

int llc_conn_ev_rx_sabme_cmd_pbit_set_x(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	return LLC_PDU_IS_CMD(pdu) && LLC_PDU_TYPE_IS_U(pdu) &&
	       LLC_U_PDU_CMD(pdu) == LLC_2_PDU_CMD_SABME ? 0 : 1;
}

int llc_conn_ev_rx_ua_rsp_fbit_set_x(struct sock *sk, struct sk_buff *skb)
{
	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	return LLC_PDU_IS_RSP(pdu) && LLC_PDU_TYPE_IS_U(pdu) &&
	       LLC_U_PDU_RSP(pdu) == LLC_2_PDU_RSP_UA ? 0 : 1;
}

int llc_conn_ev_rx_xxx_cmd_pbit_set_1(struct sock *sk, struct sk_buff *skb)
{
	u16 rc = 1;
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);

	if (LLC_PDU_IS_CMD(pdu)) {
		if (LLC_PDU_TYPE_IS_I(pdu) || LLC_PDU_TYPE_IS_S(pdu)) {
			if (LLC_I_PF_IS_1(pdu))
				rc = 0;
		} else if (LLC_PDU_TYPE_IS_U(pdu) && LLC_U_PF_IS_1(pdu))
			rc = 0;
	}
	return rc;
}

int llc_conn_ev_rx_xxx_cmd_pbit_set_x(struct sock *sk, struct sk_buff *skb)
{
	u16 rc = 1;
	const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	if (LLC_PDU_IS_CMD(pdu)) {
		if (LLC_PDU_TYPE_IS_I(pdu) || LLC_PDU_TYPE_IS_S(pdu))
			rc = 0;
		else if (LLC_PDU_TYPE_IS_U(pdu))
			switch (LLC_U_PDU_CMD(pdu)) {
			case LLC_2_PDU_CMD_SABME:
			case LLC_2_PDU_CMD_DISC:
				rc = 0;
				break;
			}
	}
	return rc;
}

int llc_conn_ev_rx_xxx_rsp_fbit_set_x(struct sock *sk, struct sk_buff *skb)
{
	u16 rc = 1;
	const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);

	if (LLC_PDU_IS_RSP(pdu)) {
		if (LLC_PDU_TYPE_IS_I(pdu) || LLC_PDU_TYPE_IS_S(pdu))
			rc = 0;
		else if (LLC_PDU_TYPE_IS_U(pdu))
			switch (LLC_U_PDU_RSP(pdu)) {
			case LLC_2_PDU_RSP_UA:
			case LLC_2_PDU_RSP_DM:
			case LLC_2_PDU_RSP_FRMR:
				rc = 0;
				break;
			}
	}

	return rc;
}

int llc_conn_ev_rx_zzz_cmd_pbit_set_x_inval_nr(struct sock *sk,
					       struct sk_buff *skb)
{
	u16 rc = 1;
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
	const u8 vs = llc_sk(sk)->vS;
	const u8 nr = LLC_I_GET_NR(pdu);

	if (LLC_PDU_IS_CMD(pdu) &&
	    (LLC_PDU_TYPE_IS_I(pdu) || LLC_PDU_TYPE_IS_S(pdu)) &&
	    nr != vs && llc_util_nr_inside_tx_window(sk, nr)) {
		dprintk("%s: matched, state=%d, vs=%d, nr=%d\n",
			__func__, llc_sk(sk)->state, vs, nr);
		rc = 0;
	}
	return rc;
}

int llc_conn_ev_rx_zzz_rsp_fbit_set_x_inval_nr(struct sock *sk,
					       struct sk_buff *skb)
{
	u16 rc = 1;
	const struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
	const u8 vs = llc_sk(sk)->vS;
	const u8 nr = LLC_I_GET_NR(pdu);

	if (LLC_PDU_IS_RSP(pdu) &&
	    (LLC_PDU_TYPE_IS_I(pdu) || LLC_PDU_TYPE_IS_S(pdu)) &&
	    nr != vs && llc_util_nr_inside_tx_window(sk, nr)) {
		rc = 0;
		dprintk("%s: matched, state=%d, vs=%d, nr=%d\n",
			__func__, llc_sk(sk)->state, vs, nr);
	}
	return rc;
}

int llc_conn_ev_rx_any_frame(struct sock *sk, struct sk_buff *skb)
{
	return 0;
}

int llc_conn_ev_p_tmr_exp(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->type != LLC_CONN_EV_TYPE_P_TMR;
}

int llc_conn_ev_ack_tmr_exp(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->type != LLC_CONN_EV_TYPE_ACK_TMR;
}

int llc_conn_ev_rej_tmr_exp(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->type != LLC_CONN_EV_TYPE_REJ_TMR;
}

int llc_conn_ev_busy_tmr_exp(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->type != LLC_CONN_EV_TYPE_BUSY_TMR;
}

int llc_conn_ev_init_p_f_cycle(struct sock *sk, struct sk_buff *skb)
{
	return 1;
}

int llc_conn_ev_tx_buffer_full(struct sock *sk, struct sk_buff *skb)
{
	const struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	return ev->type == LLC_CONN_EV_TYPE_SIMPLE &&
	       ev->prim_type == LLC_CONN_EV_TX_BUFF_FULL ? 0 : 1;
}

/* Event qualifier functions
 *
 * these functions simply verify the value of a state flag associated with
 * the connection and return either a 0 for success or a non-zero value
 * for not-success; verify the event is the type we expect
 */
int llc_conn_ev_qlfy_data_flag_eq_1(struct sock *sk, struct sk_buff *skb)
{
	return llc_sk(sk)->data_flag != 1;
}

int llc_conn_ev_qlfy_data_flag_eq_0(struct sock *sk, struct sk_buff *skb)
{
	return llc_sk(sk)->data_flag;
}

int llc_conn_ev_qlfy_data_flag_eq_2(struct sock *sk, struct sk_buff *skb)
{
	return llc_sk(sk)->data_flag != 2;
}

int llc_conn_ev_qlfy_p_flag_eq_1(struct sock *sk, struct sk_buff *skb)
{
	return llc_sk(sk)->p_flag != 1;
}

/**
 *	llc_conn_ev_qlfy_last_frame_eq_1 - checks if frame is last in tx window
 *	@sk: current connection structure.
 *	@skb: current event.
 *
 *	This function determines when frame which is sent, is last frame of
 *	transmit window, if it is then this function return zero else return
 *	one.  This function is used for sending last frame of transmit window
 *	as I-format command with p-bit set to one. Returns 0 if frame is last
 *	frame, 1 otherwise.
 */
int llc_conn_ev_qlfy_last_frame_eq_1(struct sock *sk, struct sk_buff *skb)
{
	return !(skb_queue_len(&llc_sk(sk)->pdu_unack_q) + 1 == llc_sk(sk)->k);
}

/**
 *	llc_conn_ev_qlfy_last_frame_eq_0 - checks if frame isn't last in tx window
 *	@sk: current connection structure.
 *	@skb: current event.
 *
 *	This function determines when frame which is sent, isn't last frame of
 *	transmit window, if it isn't then this function return zero else return
 *	one. Returns 0 if frame isn't last frame, 1 otherwise.
 */
int llc_conn_ev_qlfy_last_frame_eq_0(struct sock *sk, struct sk_buff *skb)
{
	return skb_queue_len(&llc_sk(sk)->pdu_unack_q) + 1 == llc_sk(sk)->k;
}

int llc_conn_ev_qlfy_p_flag_eq_0(struct sock *sk, struct sk_buff *skb)
{
	return llc_sk(sk)->p_flag;
}

int llc_conn_ev_qlfy_p_flag_eq_f(struct sock *sk, struct sk_buff *skb)
{
	u8 f_bit;

	llc_pdu_decode_pf_bit(skb, &f_bit);
	return llc_sk(sk)->p_flag == f_bit ? 0 : 1;
}

int llc_conn_ev_qlfy_remote_busy_eq_0(struct sock *sk, struct sk_buff *skb)
{
	return llc_sk(sk)->remote_busy_flag;
}

int llc_conn_ev_qlfy_remote_busy_eq_1(struct sock *sk, struct sk_buff *skb)
{
	return !llc_sk(sk)->remote_busy_flag;
}

int llc_conn_ev_qlfy_retry_cnt_lt_n2(struct sock *sk, struct sk_buff *skb)
{
	return !(llc_sk(sk)->retry_count < llc_sk(sk)->n2);
}

int llc_conn_ev_qlfy_retry_cnt_gte_n2(struct sock *sk, struct sk_buff *skb)
{
	return !(llc_sk(sk)->retry_count >= llc_sk(sk)->n2);
}

int llc_conn_ev_qlfy_s_flag_eq_1(struct sock *sk, struct sk_buff *skb)
{
	return !llc_sk(sk)->s_flag;
}

int llc_conn_ev_qlfy_s_flag_eq_0(struct sock *sk, struct sk_buff *skb)
{
	return llc_sk(sk)->s_flag;
}

int llc_conn_ev_qlfy_cause_flag_eq_1(struct sock *sk, struct sk_buff *skb)
{
	return !llc_sk(sk)->cause_flag;
}

int llc_conn_ev_qlfy_cause_flag_eq_0(struct sock *sk, struct sk_buff *skb)
{
	return llc_sk(sk)->cause_flag;
}

int llc_conn_ev_qlfy_set_status_conn(struct sock *sk, struct sk_buff *skb)
{
	struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	ev->status = LLC_STATUS_CONN;
	return 0;
}

int llc_conn_ev_qlfy_set_status_disc(struct sock *sk, struct sk_buff *skb)
{
	struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	ev->status = LLC_STATUS_DISC;
	return 0;
}

int llc_conn_ev_qlfy_set_status_failed(struct sock *sk, struct sk_buff *skb)
{
	struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	ev->status = LLC_STATUS_FAILED;
	return 0;
}

int llc_conn_ev_qlfy_set_status_remote_busy(struct sock *sk,
					    struct sk_buff *skb)
{
	struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	ev->status = LLC_STATUS_REMOTE_BUSY;
	return 0;
}

int llc_conn_ev_qlfy_set_status_refuse(struct sock *sk, struct sk_buff *skb)
{
	struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	ev->status = LLC_STATUS_REFUSE;
	return 0;
}

int llc_conn_ev_qlfy_set_status_conflict(struct sock *sk, struct sk_buff *skb)
{
	struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	ev->status = LLC_STATUS_CONFLICT;
	return 0;
}

int llc_conn_ev_qlfy_set_status_rst_done(struct sock *sk, struct sk_buff *skb)
{
	struct llc_conn_state_ev *ev = llc_conn_ev(skb);

	ev->status = LLC_STATUS_RESET_DONE;
	return 0;
}