1/*
2 * CAPI encoder/decoder for
3 * Portugal Telecom CAPI 2.0
4 *
5 * Copyright (C) 1996 Universidade de Lisboa
6 *
7 * Written by Pedro Roque Marques (roque@di.fc.ul.pt)
8 *
9 * This software may be used and distributed according to the terms of
10 * the GNU General Public License, incorporated herein by reference.
11 *
12 * Not compatible with the AVM Gmbh. CAPI 2.0
13 *
14 */
15
16/*
17 *        Documentation:
18 *        - "Common ISDN API - Perfil Português - Versão 2.1",
19 *           Telecom Portugal, Fev 1992.
20 *        - "Common ISDN API - Especificação de protocolos para
21 *           acesso aos canais B", Inesc, Jan 1994.
22 */
23
24/*
25 *        TODO: better decoding of Information Elements
26 *              for debug purposes mainly
27 *              encode our number in CallerPN and ConnectedPN
28 */
29
30#include <linux/string.h>
31#include <linux/kernel.h>
32
33#include <linux/types.h>
34#include <linux/slab.h>
35#include <linux/mm.h>
36
37#include <linux/skbuff.h>
38
39#include <asm/io.h>
40#include <asm/string.h>
41
42#include <linux/isdnif.h>
43
44#include "pcbit.h"
45#include "edss1.h"
46#include "capi.h"
47
48
49/*
50 *  Encoding of CAPI messages
51 *
52 */
53
54int capi_conn_req(const char *calledPN, struct sk_buff **skb, int proto)
55{
56	ushort len;
57
58	/*
59	 * length
60	 *   AppInfoMask - 2
61	 *   BC0         - 3
62	 *   BC1         - 1
63	 *   Chan        - 2
64	 *   Keypad      - 1
65	 *   CPN         - 1
66	 *   CPSA        - 1
67	 *   CalledPN    - 2 + strlen
68	 *   CalledPSA   - 1
69	 *   rest...     - 4
70	 *   ----------------
71	 *   Total        18 + strlen
72	 */
73
74	len = 18 + strlen(calledPN);
75
76	if (proto == ISDN_PROTO_L2_TRANS)
77		len++;
78
79	if ((*skb = dev_alloc_skb(len)) == NULL) {
80
81		printk(KERN_WARNING "capi_conn_req: alloc_skb failed\n");
82		return -1;
83	}
84
85	/* InfoElmMask */
86	*((ushort *)skb_put(*skb, 2)) = AppInfoMask;
87
88	if (proto == ISDN_PROTO_L2_TRANS)
89	{
90		/* Bearer Capability - Mandatory*/
91		*(skb_put(*skb, 1)) = 3;        /* BC0.Length		*/
92		*(skb_put(*skb, 1)) = 0x80;     /* Speech		*/
93		*(skb_put(*skb, 1)) = 0x10;     /* Circuit Mode		*/
94		*(skb_put(*skb, 1)) = 0x23;     /* A-law		*/
95	}
96	else
97	{
98		/* Bearer Capability - Mandatory*/
99		*(skb_put(*skb, 1)) = 2;        /* BC0.Length		*/
100		*(skb_put(*skb, 1)) = 0x88;     /* Digital Information	*/
101		*(skb_put(*skb, 1)) = 0x90;     /* BC0.Octect4		*/
102	}
103
104	/* Bearer Capability - Optional*/
105	*(skb_put(*skb, 1)) = 0;        /* BC1.Length = 0                    */
106
107	*(skb_put(*skb, 1)) = 1;        /* ChannelID.Length = 1              */
108	*(skb_put(*skb, 1)) = 0x83;     /* Basic Interface - Any Channel     */
109
110	*(skb_put(*skb, 1)) = 0;        /* Keypad.Length = 0                 */
111
112
113	*(skb_put(*skb, 1)) = 0;        /* CallingPN.Length = 0              */
114	*(skb_put(*skb, 1)) = 0;        /* CallingPSA.Length = 0             */
115
116	/* Called Party Number */
117	*(skb_put(*skb, 1)) = strlen(calledPN) + 1;
118	*(skb_put(*skb, 1)) = 0x81;
119	memcpy(skb_put(*skb, strlen(calledPN)), calledPN, strlen(calledPN));
120
121	/* '#' */
122
123	*(skb_put(*skb, 1)) = 0;       /* CalledPSA.Length = 0     */
124
125	/* LLC.Length  = 0; */
126	/* HLC0.Length = 0; */
127	/* HLC1.Length = 0; */
128	/* UTUS.Length = 0; */
129	memset(skb_put(*skb, 4), 0, 4);
130
131	return len;
132}
133
134int capi_conn_resp(struct pcbit_chan *chan, struct sk_buff **skb)
135{
136
137	if ((*skb = dev_alloc_skb(5)) == NULL) {
138
139		printk(KERN_WARNING "capi_conn_resp: alloc_skb failed\n");
140		return -1;
141	}
142
143	*((ushort *)skb_put(*skb, 2)) = chan->callref;
144	*(skb_put(*skb, 1)) = 0x01;  /* ACCEPT_CALL */
145	*(skb_put(*skb, 1)) = 0;
146	*(skb_put(*skb, 1)) = 0;
147
148	return 5;
149}
150
151int capi_conn_active_req(struct pcbit_chan *chan, struct sk_buff **skb)
152{
153	/*
154	 * 8 bytes
155	 */
156
157	if ((*skb = dev_alloc_skb(8)) == NULL) {
158
159		printk(KERN_WARNING "capi_conn_active_req: alloc_skb failed\n");
160		return -1;
161	}
162
163	*((ushort *)skb_put(*skb, 2)) = chan->callref;
164
165#ifdef DEBUG
166	printk(KERN_DEBUG "Call Reference: %04x\n", chan->callref);
167#endif
168
169	*(skb_put(*skb, 1)) = 0;       /*  BC.Length = 0;          */
170	*(skb_put(*skb, 1)) = 0;       /*  ConnectedPN.Length = 0  */
171	*(skb_put(*skb, 1)) = 0;       /*  PSA.Length              */
172	*(skb_put(*skb, 1)) = 0;       /*  LLC.Length = 0;         */
173	*(skb_put(*skb, 1)) = 0;       /*  HLC.Length = 0;         */
174	*(skb_put(*skb, 1)) = 0;       /*  UTUS.Length = 0;        */
175
176	return 8;
177}
178
179int capi_conn_active_resp(struct pcbit_chan *chan, struct sk_buff **skb)
180{
181	/*
182	 * 2 bytes
183	 */
184
185	if ((*skb = dev_alloc_skb(2)) == NULL) {
186
187		printk(KERN_WARNING "capi_conn_active_resp: alloc_skb failed\n");
188		return -1;
189	}
190
191	*((ushort *)skb_put(*skb, 2)) = chan->callref;
192
193	return 2;
194}
195
196
197int capi_select_proto_req(struct pcbit_chan *chan, struct sk_buff **skb,
198			  int outgoing)
199{
200
201	/*
202	 * 18 bytes
203	 */
204
205	if ((*skb = dev_alloc_skb(18)) == NULL) {
206
207		printk(KERN_WARNING "capi_select_proto_req: alloc_skb failed\n");
208		return -1;
209	}
210
211	*((ushort *)skb_put(*skb, 2)) = chan->callref;
212
213	/* Layer2 protocol */
214
215	switch (chan->proto) {
216	case ISDN_PROTO_L2_X75I:
217		*(skb_put(*skb, 1)) = 0x05;            /* LAPB */
218		break;
219	case ISDN_PROTO_L2_HDLC:
220		*(skb_put(*skb, 1)) = 0x02;
221		break;
222	case ISDN_PROTO_L2_TRANS:
223		/*
224		 *	Voice (a-law)
225		 */
226		*(skb_put(*skb, 1)) = 0x06;
227		break;
228	default:
229#ifdef DEBUG
230		printk(KERN_DEBUG "Transparent\n");
231#endif
232		*(skb_put(*skb, 1)) = 0x03;
233		break;
234	}
235
236	*(skb_put(*skb, 1)) = (outgoing ? 0x02 : 0x42);    /* Don't ask */
237	*(skb_put(*skb, 1)) = 0x00;
238
239	*((ushort *) skb_put(*skb, 2)) = MRU;
240
241
242	*(skb_put(*skb, 1)) = 0x08;           /* Modulo */
243	*(skb_put(*skb, 1)) = 0x07;           /* Max Window */
244
245	*(skb_put(*skb, 1)) = 0x01;           /* No Layer3 Protocol */
246
247	/*
248	 * 2 - layer3 MTU       [10]
249	 *   - Modulo           [12]
250	 *   - Window
251	 *   - layer1 proto     [14]
252	 *   - bitrate
253	 *   - sub-channel      [16]
254	 *   - layer1dataformat [17]
255	 */
256
257	memset(skb_put(*skb, 8), 0, 8);
258
259	return 18;
260}
261
262
263int capi_activate_transp_req(struct pcbit_chan *chan, struct sk_buff **skb)
264{
265
266	if ((*skb = dev_alloc_skb(7)) == NULL) {
267
268		printk(KERN_WARNING "capi_activate_transp_req: alloc_skb failed\n");
269		return -1;
270	}
271
272	*((ushort *)skb_put(*skb, 2)) = chan->callref;
273
274
275	*(skb_put(*skb, 1)) = chan->layer2link; /* Layer2 id */
276	*(skb_put(*skb, 1)) = 0x00;             /* Transmit by default */
277
278	*((ushort *) skb_put(*skb, 2)) = MRU;
279
280	*(skb_put(*skb, 1)) = 0x01;             /* Enables reception*/
281
282	return 7;
283}
284
285int capi_tdata_req(struct pcbit_chan *chan, struct sk_buff *skb)
286{
287	ushort data_len;
288
289
290	/*
291	 * callref      - 2
292	 * layer2link   - 1
293	 * wBlockLength - 2
294	 * data         - 4
295	 * sernum       - 1
296	 */
297
298	data_len = skb->len;
299
300	if (skb_headroom(skb) < 10)
301	{
302		printk(KERN_CRIT "No headspace (%u) on headroom %p for capi header\n", skb_headroom(skb), skb);
303	}
304	else
305	{
306		skb_push(skb, 10);
307	}
308
309	*((u16 *) (skb->data)) = chan->callref;
310	skb->data[2] = chan->layer2link;
311	*((u16 *) (skb->data + 3)) = data_len;
312
313	chan->s_refnum = (chan->s_refnum + 1) % 8;
314	*((u32 *) (skb->data + 5)) = chan->s_refnum;
315
316	skb->data[9] = 0;                           /* HDLC frame number */
317
318	return 10;
319}
320
321int capi_tdata_resp(struct pcbit_chan *chan, struct sk_buff **skb)
322
323{
324	if ((*skb = dev_alloc_skb(4)) == NULL) {
325
326		printk(KERN_WARNING "capi_tdata_resp: alloc_skb failed\n");
327		return -1;
328	}
329
330	*((ushort *)skb_put(*skb, 2)) = chan->callref;
331
332	*(skb_put(*skb, 1)) = chan->layer2link;
333	*(skb_put(*skb, 1)) = chan->r_refnum;
334
335	return (*skb)->len;
336}
337
338int capi_disc_req(ushort callref, struct sk_buff **skb, u_char cause)
339{
340
341	if ((*skb = dev_alloc_skb(6)) == NULL) {
342
343		printk(KERN_WARNING "capi_disc_req: alloc_skb failed\n");
344		return -1;
345	}
346
347	*((ushort *)skb_put(*skb, 2)) = callref;
348
349	*(skb_put(*skb, 1)) = 2;                  /* Cause.Length = 2; */
350	*(skb_put(*skb, 1)) = 0x80;
351	*(skb_put(*skb, 1)) = 0x80 | cause;
352
353	/*
354	 * Change it: we should send 'Sic transit gloria Mundi' here ;-)
355	 */
356
357	*(skb_put(*skb, 1)) = 0;                   /* UTUS.Length = 0;  */
358
359	return 6;
360}
361
362int capi_disc_resp(struct pcbit_chan *chan, struct sk_buff **skb)
363{
364	if ((*skb = dev_alloc_skb(2)) == NULL) {
365
366		printk(KERN_WARNING "capi_disc_resp: alloc_skb failed\n");
367		return -1;
368	}
369
370	*((ushort *)skb_put(*skb, 2)) = chan->callref;
371
372	return 2;
373}
374
375
376/*
377 *  Decoding of CAPI messages
378 *
379 */
380
381int capi_decode_conn_ind(struct pcbit_chan *chan,
382			 struct sk_buff *skb,
383			 struct callb_data *info)
384{
385	int CIlen, len;
386
387	/* Call Reference [CAPI] */
388	chan->callref = *((ushort *)skb->data);
389	skb_pull(skb, 2);
390
391#ifdef DEBUG
392	printk(KERN_DEBUG "Call Reference: %04x\n", chan->callref);
393#endif
394
395	/* Channel Identification */
396
397	/* Expect
398	   Len = 1
399	   Octect 3 = 0100 10CC - [ 7 Basic, 4 , 2-1 chan ]
400	*/
401
402	CIlen = skb->data[0];
403#ifdef DEBUG
404	if (CIlen == 1) {
405
406		if (((skb->data[1]) & 0xFC) == 0x48)
407			printk(KERN_DEBUG "decode_conn_ind: chan ok\n");
408		printk(KERN_DEBUG "phyChan = %d\n", skb->data[1] & 0x03);
409	}
410	else
411		printk(KERN_DEBUG "conn_ind: CIlen = %d\n", CIlen);
412#endif
413	skb_pull(skb, CIlen + 1);
414
415	/* Calling Party Number */
416	/* An "additional service" as far as Portugal Telecom is concerned */
417
418	len = skb->data[0];
419
420	if (len > 0) {
421		int count = 1;
422
423#ifdef DEBUG
424		printk(KERN_DEBUG "CPN: Octect 3 %02x\n", skb->data[1]);
425#endif
426		if ((skb->data[1] & 0x80) == 0)
427			count = 2;
428
429		if (!(info->data.setup.CallingPN = kmalloc(len - count + 1, GFP_ATOMIC)))
430			return -1;
431
432		skb_copy_from_linear_data_offset(skb, count + 1,
433						 info->data.setup.CallingPN,
434						 len - count);
435		info->data.setup.CallingPN[len - count] = 0;
436
437	}
438	else {
439		info->data.setup.CallingPN = NULL;
440		printk(KERN_DEBUG "NULL CallingPN\n");
441	}
442
443	skb_pull(skb, len + 1);
444
445	/* Calling Party Subaddress */
446	skb_pull(skb, skb->data[0] + 1);
447
448	/* Called Party Number */
449
450	len = skb->data[0];
451
452	if (len > 0) {
453		int count = 1;
454
455		if ((skb->data[1] & 0x80) == 0)
456			count = 2;
457
458		if (!(info->data.setup.CalledPN = kmalloc(len - count + 1, GFP_ATOMIC)))
459			return -1;
460
461		skb_copy_from_linear_data_offset(skb, count + 1,
462						 info->data.setup.CalledPN,
463						 len - count);
464		info->data.setup.CalledPN[len - count] = 0;
465
466	}
467	else {
468		info->data.setup.CalledPN = NULL;
469		printk(KERN_DEBUG "NULL CalledPN\n");
470	}
471
472	skb_pull(skb, len + 1);
473
474	/* Called Party Subaddress */
475	skb_pull(skb, skb->data[0] + 1);
476
477	/* LLC */
478	skb_pull(skb, skb->data[0] + 1);
479
480	/* HLC */
481	skb_pull(skb, skb->data[0] + 1);
482
483	/* U2U */
484	skb_pull(skb, skb->data[0] + 1);
485
486	return 0;
487}
488
489/*
490 *  returns errcode
491 */
492
493int capi_decode_conn_conf(struct pcbit_chan *chan, struct sk_buff *skb,
494			  int *complete)
495{
496	int errcode;
497
498	chan->callref = *((ushort *)skb->data);     /* Update CallReference */
499	skb_pull(skb, 2);
500
501	errcode = *((ushort *) skb->data);   /* read errcode */
502	skb_pull(skb, 2);
503
504	*complete = *(skb->data);
505	skb_pull(skb, 1);
506
507	/* FIX ME */
508	/* This is actually a firmware bug */
509	if (!*complete)
510	{
511		printk(KERN_DEBUG "complete=%02x\n", *complete);
512		*complete = 1;
513	}
514
515
516	/* Optional Bearer Capability */
517	skb_pull(skb, *(skb->data) + 1);
518
519	/* Channel Identification */
520	skb_pull(skb, *(skb->data) + 1);
521
522	/* High Layer Compatibility follows */
523	skb_pull(skb, *(skb->data) + 1);
524
525	return errcode;
526}
527
528int capi_decode_conn_actv_ind(struct pcbit_chan *chan, struct sk_buff *skb)
529{
530	ushort len;
531#ifdef DEBUG
532	char str[32];
533#endif
534
535	/* Yet Another Bearer Capability */
536	skb_pull(skb, *(skb->data) + 1);
537
538
539	/* Connected Party Number */
540	len = *(skb->data);
541
542#ifdef DEBUG
543	if (len > 1 && len < 31) {
544		skb_copy_from_linear_data_offset(skb, 2, str, len - 1);
545		str[len] = 0;
546		printk(KERN_DEBUG "Connected Party Number: %s\n", str);
547	}
548	else
549		printk(KERN_DEBUG "actv_ind CPN len = %d\n", len);
550#endif
551
552	skb_pull(skb, len + 1);
553
554	/* Connected Subaddress */
555	skb_pull(skb, *(skb->data) + 1);
556
557	/* Low Layer Capability */
558	skb_pull(skb, *(skb->data) + 1);
559
560	/* High Layer Capability */
561	skb_pull(skb, *(skb->data) + 1);
562
563	return 0;
564}
565
566int capi_decode_conn_actv_conf(struct pcbit_chan *chan, struct sk_buff *skb)
567{
568	ushort errcode;
569
570	errcode = *((ushort *)skb->data);
571	skb_pull(skb, 2);
572
573	/* Channel Identification
574	   skb_pull(skb, skb->data[0] + 1);
575	*/
576	return errcode;
577}
578
579
580int capi_decode_sel_proto_conf(struct pcbit_chan *chan, struct sk_buff *skb)
581{
582	ushort errcode;
583
584	chan->layer2link = *(skb->data);
585	skb_pull(skb, 1);
586
587	errcode = *((ushort *)skb->data);
588	skb_pull(skb, 2);
589
590	return errcode;
591}
592
593int capi_decode_actv_trans_conf(struct pcbit_chan *chan, struct sk_buff *skb)
594{
595	ushort errcode;
596
597	if (chan->layer2link != *(skb->data))
598		printk("capi_decode_actv_trans_conf: layer2link doesn't match\n");
599
600	skb_pull(skb, 1);
601
602	errcode = *((ushort *)skb->data);
603	skb_pull(skb, 2);
604
605	return errcode;
606}
607
608int capi_decode_disc_ind(struct pcbit_chan *chan, struct sk_buff *skb)
609{
610	ushort len;
611#ifdef DEBUG
612	int i;
613#endif
614	/* Cause */
615
616	len = *(skb->data);
617	skb_pull(skb, 1);
618
619#ifdef DEBUG
620
621	for (i = 0; i < len; i++)
622		printk(KERN_DEBUG "Cause Octect %d: %02x\n", i + 3,
623		       *(skb->data + i));
624#endif
625
626	skb_pull(skb, len);
627
628	return 0;
629}
630
631#ifdef DEBUG
632int capi_decode_debug_188(u_char *hdr, ushort hdrlen)
633{
634	char str[64];
635	int len;
636
637	len = hdr[0];
638
639	if (len < 64 && len == hdrlen - 1) {
640		memcpy(str, hdr + 1, hdrlen - 1);
641		str[hdrlen - 1] = 0;
642		printk("%s\n", str);
643	}
644	else
645		printk("debug message incorrect\n");
646
647	return 0;
648}
649#endif
650