1/*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
8 */
9#include <linux/errno.h>
10#include <linux/types.h>
11#include <linux/socket.h>
12#include <linux/in.h>
13#include <linux/kernel.h>
14#include <linux/timer.h>
15#include <linux/string.h>
16#include <linux/sockios.h>
17#include <linux/net.h>
18#include <net/ax25.h>
19#include <linux/inet.h>
20#include <linux/netdevice.h>
21#include <linux/skbuff.h>
22#include <net/sock.h>
23#include <net/tcp_states.h>
24#include <asm/system.h>
25#include <linux/fcntl.h>
26#include <linux/mm.h>
27#include <linux/interrupt.h>
28#include <net/rose.h>
29
30static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose);
31
32/*
33 *	This routine purges all of the queues of frames.
34 */
35void rose_clear_queues(struct sock *sk)
36{
37	skb_queue_purge(&sk->sk_write_queue);
38	skb_queue_purge(&rose_sk(sk)->ack_queue);
39}
40
41/*
42 * This routine purges the input queue of those frames that have been
43 * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
44 * SDL diagram.
45 */
46void rose_frames_acked(struct sock *sk, unsigned short nr)
47{
48	struct sk_buff *skb;
49	struct rose_sock *rose = rose_sk(sk);
50
51	/*
52	 * Remove all the ack-ed frames from the ack queue.
53	 */
54	if (rose->va != nr) {
55		while (skb_peek(&rose->ack_queue) != NULL && rose->va != nr) {
56			skb = skb_dequeue(&rose->ack_queue);
57			kfree_skb(skb);
58			rose->va = (rose->va + 1) % ROSE_MODULUS;
59		}
60	}
61}
62
63void rose_requeue_frames(struct sock *sk)
64{
65	struct sk_buff *skb, *skb_prev = NULL;
66
67	/*
68	 * Requeue all the un-ack-ed frames on the output queue to be picked
69	 * up by rose_kick. This arrangement handles the possibility of an
70	 * empty output queue.
71	 */
72	while ((skb = skb_dequeue(&rose_sk(sk)->ack_queue)) != NULL) {
73		if (skb_prev == NULL)
74			skb_queue_head(&sk->sk_write_queue, skb);
75		else
76			skb_append(skb_prev, skb, &sk->sk_write_queue);
77		skb_prev = skb;
78	}
79}
80
81/*
82 *	Validate that the value of nr is between va and vs. Return true or
83 *	false for testing.
84 */
85int rose_validate_nr(struct sock *sk, unsigned short nr)
86{
87	struct rose_sock *rose = rose_sk(sk);
88	unsigned short vc = rose->va;
89
90	while (vc != rose->vs) {
91		if (nr == vc) return 1;
92		vc = (vc + 1) % ROSE_MODULUS;
93	}
94
95	return nr == rose->vs;
96}
97
98/*
99 *  This routine is called when the packet layer internally generates a
100 *  control frame.
101 */
102void rose_write_internal(struct sock *sk, int frametype)
103{
104	struct rose_sock *rose = rose_sk(sk);
105	struct sk_buff *skb;
106	unsigned char  *dptr;
107	unsigned char  lci1, lci2;
108	char buffer[100];
109	int len, faclen = 0;
110
111	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
112
113	switch (frametype) {
114	case ROSE_CALL_REQUEST:
115		len   += 1 + ROSE_ADDR_LEN + ROSE_ADDR_LEN;
116		faclen = rose_create_facilities(buffer, rose);
117		len   += faclen;
118		break;
119	case ROSE_CALL_ACCEPTED:
120	case ROSE_CLEAR_REQUEST:
121	case ROSE_RESET_REQUEST:
122		len   += 2;
123		break;
124	}
125
126	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
127		return;
128
129	/*
130	 *	Space for AX.25 header and PID.
131	 */
132	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + 1);
133
134	dptr = skb_put(skb, skb_tailroom(skb));
135
136	lci1 = (rose->lci >> 8) & 0x0F;
137	lci2 = (rose->lci >> 0) & 0xFF;
138
139	switch (frametype) {
140	case ROSE_CALL_REQUEST:
141		*dptr++ = ROSE_GFI | lci1;
142		*dptr++ = lci2;
143		*dptr++ = frametype;
144		*dptr++ = 0xAA;
145		memcpy(dptr, &rose->dest_addr,  ROSE_ADDR_LEN);
146		dptr   += ROSE_ADDR_LEN;
147		memcpy(dptr, &rose->source_addr, ROSE_ADDR_LEN);
148		dptr   += ROSE_ADDR_LEN;
149		memcpy(dptr, buffer, faclen);
150		dptr   += faclen;
151		break;
152
153	case ROSE_CALL_ACCEPTED:
154		*dptr++ = ROSE_GFI | lci1;
155		*dptr++ = lci2;
156		*dptr++ = frametype;
157		*dptr++ = 0x00;		/* Address length */
158		*dptr++ = 0;		/* Facilities length */
159		break;
160
161	case ROSE_CLEAR_REQUEST:
162		*dptr++ = ROSE_GFI | lci1;
163		*dptr++ = lci2;
164		*dptr++ = frametype;
165		*dptr++ = rose->cause;
166		*dptr++ = rose->diagnostic;
167		break;
168
169	case ROSE_RESET_REQUEST:
170		*dptr++ = ROSE_GFI | lci1;
171		*dptr++ = lci2;
172		*dptr++ = frametype;
173		*dptr++ = ROSE_DTE_ORIGINATED;
174		*dptr++ = 0;
175		break;
176
177	case ROSE_RR:
178	case ROSE_RNR:
179		*dptr++ = ROSE_GFI | lci1;
180		*dptr++ = lci2;
181		*dptr   = frametype;
182		*dptr++ |= (rose->vr << 5) & 0xE0;
183		break;
184
185	case ROSE_CLEAR_CONFIRMATION:
186	case ROSE_RESET_CONFIRMATION:
187		*dptr++ = ROSE_GFI | lci1;
188		*dptr++ = lci2;
189		*dptr++  = frametype;
190		break;
191
192	default:
193		printk(KERN_ERR "ROSE: rose_write_internal - invalid frametype %02X\n", frametype);
194		kfree_skb(skb);
195		return;
196	}
197
198	rose_transmit_link(skb, rose->neighbour);
199}
200
201int rose_decode(struct sk_buff *skb, int *ns, int *nr, int *q, int *d, int *m)
202{
203	unsigned char *frame;
204
205	frame = skb->data;
206
207	*ns = *nr = *q = *d = *m = 0;
208
209	switch (frame[2]) {
210	case ROSE_CALL_REQUEST:
211	case ROSE_CALL_ACCEPTED:
212	case ROSE_CLEAR_REQUEST:
213	case ROSE_CLEAR_CONFIRMATION:
214	case ROSE_RESET_REQUEST:
215	case ROSE_RESET_CONFIRMATION:
216		return frame[2];
217	default:
218		break;
219	}
220
221	if ((frame[2] & 0x1F) == ROSE_RR  ||
222	    (frame[2] & 0x1F) == ROSE_RNR) {
223		*nr = (frame[2] >> 5) & 0x07;
224		return frame[2] & 0x1F;
225	}
226
227	if ((frame[2] & 0x01) == ROSE_DATA) {
228		*q  = (frame[0] & ROSE_Q_BIT) == ROSE_Q_BIT;
229		*d  = (frame[0] & ROSE_D_BIT) == ROSE_D_BIT;
230		*m  = (frame[2] & ROSE_M_BIT) == ROSE_M_BIT;
231		*nr = (frame[2] >> 5) & 0x07;
232		*ns = (frame[2] >> 1) & 0x07;
233		return ROSE_DATA;
234	}
235
236	return ROSE_ILLEGAL;
237}
238
239static int rose_parse_national(unsigned char *p, struct rose_facilities_struct *facilities, int len)
240{
241	unsigned char *pt;
242	unsigned char l, lg, n = 0;
243	int fac_national_digis_received = 0;
244
245	do {
246		switch (*p & 0xC0) {
247		case 0x00:
248			p   += 2;
249			n   += 2;
250			len -= 2;
251			break;
252
253		case 0x40:
254			if (*p == FAC_NATIONAL_RAND)
255				facilities->rand = ((p[1] << 8) & 0xFF00) + ((p[2] << 0) & 0x00FF);
256			p   += 3;
257			n   += 3;
258			len -= 3;
259			break;
260
261		case 0x80:
262			p   += 4;
263			n   += 4;
264			len -= 4;
265			break;
266
267		case 0xC0:
268			l = p[1];
269			if (*p == FAC_NATIONAL_DEST_DIGI) {
270				if (!fac_national_digis_received) {
271					memcpy(&facilities->source_digis[0], p + 2, AX25_ADDR_LEN);
272					facilities->source_ndigis = 1;
273				}
274			}
275			else if (*p == FAC_NATIONAL_SRC_DIGI) {
276				if (!fac_national_digis_received) {
277					memcpy(&facilities->dest_digis[0], p + 2, AX25_ADDR_LEN);
278					facilities->dest_ndigis = 1;
279				}
280			}
281			else if (*p == FAC_NATIONAL_FAIL_CALL) {
282				memcpy(&facilities->fail_call, p + 2, AX25_ADDR_LEN);
283			}
284			else if (*p == FAC_NATIONAL_FAIL_ADD) {
285				memcpy(&facilities->fail_addr, p + 3, ROSE_ADDR_LEN);
286			}
287			else if (*p == FAC_NATIONAL_DIGIS) {
288				fac_national_digis_received = 1;
289				facilities->source_ndigis = 0;
290				facilities->dest_ndigis   = 0;
291				for (pt = p + 2, lg = 0 ; lg < l ; pt += AX25_ADDR_LEN, lg += AX25_ADDR_LEN) {
292					if (pt[6] & AX25_HBIT)
293						memcpy(&facilities->dest_digis[facilities->dest_ndigis++], pt, AX25_ADDR_LEN);
294					else
295						memcpy(&facilities->source_digis[facilities->source_ndigis++], pt, AX25_ADDR_LEN);
296				}
297			}
298			p   += l + 2;
299			n   += l + 2;
300			len -= l + 2;
301			break;
302		}
303	} while (*p != 0x00 && len > 0);
304
305	return n;
306}
307
308static int rose_parse_ccitt(unsigned char *p, struct rose_facilities_struct *facilities, int len)
309{
310	unsigned char l, n = 0;
311	char callsign[11];
312
313	do {
314		switch (*p & 0xC0) {
315		case 0x00:
316			p   += 2;
317			n   += 2;
318			len -= 2;
319			break;
320
321		case 0x40:
322			p   += 3;
323			n   += 3;
324			len -= 3;
325			break;
326
327		case 0x80:
328			p   += 4;
329			n   += 4;
330			len -= 4;
331			break;
332
333		case 0xC0:
334			l = p[1];
335			if (*p == FAC_CCITT_DEST_NSAP) {
336				memcpy(&facilities->source_addr, p + 7, ROSE_ADDR_LEN);
337				memcpy(callsign, p + 12,   l - 10);
338				callsign[l - 10] = '\0';
339				asc2ax(&facilities->source_call, callsign);
340			}
341			if (*p == FAC_CCITT_SRC_NSAP) {
342				memcpy(&facilities->dest_addr, p + 7, ROSE_ADDR_LEN);
343				memcpy(callsign, p + 12, l - 10);
344				callsign[l - 10] = '\0';
345				asc2ax(&facilities->dest_call, callsign);
346			}
347			p   += l + 2;
348			n   += l + 2;
349			len -= l + 2;
350			break;
351		}
352	} while (*p != 0x00 && len > 0);
353
354	return n;
355}
356
357int rose_parse_facilities(unsigned char *p,
358	struct rose_facilities_struct *facilities)
359{
360	int facilities_len, len;
361
362	facilities_len = *p++;
363
364	if (facilities_len == 0)
365		return 0;
366
367	while (facilities_len > 0) {
368		if (*p == 0x00) {
369			facilities_len--;
370			p++;
371
372			switch (*p) {
373			case FAC_NATIONAL:		/* National */
374				len = rose_parse_national(p + 1, facilities, facilities_len - 1);
375				facilities_len -= len + 1;
376				p += len + 1;
377				break;
378
379			case FAC_CCITT:		/* CCITT */
380				len = rose_parse_ccitt(p + 1, facilities, facilities_len - 1);
381				facilities_len -= len + 1;
382				p += len + 1;
383				break;
384
385			default:
386				printk(KERN_DEBUG "ROSE: rose_parse_facilities - unknown facilities family %02X\n", *p);
387				facilities_len--;
388				p++;
389				break;
390			}
391		} else
392			break;	/* Error in facilities format */
393	}
394
395	return 1;
396}
397
398static int rose_create_facilities(unsigned char *buffer, struct rose_sock *rose)
399{
400	unsigned char *p = buffer + 1;
401	char *callsign;
402	char buf[11];
403	int len, nb;
404
405	/* National Facilities */
406	if (rose->rand != 0 || rose->source_ndigis == 1 || rose->dest_ndigis == 1) {
407		*p++ = 0x00;
408		*p++ = FAC_NATIONAL;
409
410		if (rose->rand != 0) {
411			*p++ = FAC_NATIONAL_RAND;
412			*p++ = (rose->rand >> 8) & 0xFF;
413			*p++ = (rose->rand >> 0) & 0xFF;
414		}
415
416		/* Sent before older facilities */
417		if ((rose->source_ndigis > 0) || (rose->dest_ndigis > 0)) {
418			int maxdigi = 0;
419			*p++ = FAC_NATIONAL_DIGIS;
420			*p++ = AX25_ADDR_LEN * (rose->source_ndigis + rose->dest_ndigis);
421			for (nb = 0 ; nb < rose->source_ndigis ; nb++) {
422				if (++maxdigi >= ROSE_MAX_DIGIS)
423					break;
424				memcpy(p, &rose->source_digis[nb], AX25_ADDR_LEN);
425				p[6] |= AX25_HBIT;
426				p += AX25_ADDR_LEN;
427			}
428			for (nb = 0 ; nb < rose->dest_ndigis ; nb++) {
429				if (++maxdigi >= ROSE_MAX_DIGIS)
430					break;
431				memcpy(p, &rose->dest_digis[nb], AX25_ADDR_LEN);
432				p[6] &= ~AX25_HBIT;
433				p += AX25_ADDR_LEN;
434			}
435		}
436
437		/* For compatibility */
438		if (rose->source_ndigis > 0) {
439			*p++ = FAC_NATIONAL_SRC_DIGI;
440			*p++ = AX25_ADDR_LEN;
441			memcpy(p, &rose->source_digis[0], AX25_ADDR_LEN);
442			p   += AX25_ADDR_LEN;
443		}
444
445		/* For compatibility */
446		if (rose->dest_ndigis > 0) {
447			*p++ = FAC_NATIONAL_DEST_DIGI;
448			*p++ = AX25_ADDR_LEN;
449			memcpy(p, &rose->dest_digis[0], AX25_ADDR_LEN);
450			p   += AX25_ADDR_LEN;
451		}
452	}
453
454	*p++ = 0x00;
455	*p++ = FAC_CCITT;
456
457	*p++ = FAC_CCITT_DEST_NSAP;
458
459	callsign = ax2asc(buf, &rose->dest_call);
460
461	*p++ = strlen(callsign) + 10;
462	*p++ = (strlen(callsign) + 9) * 2;		/* ??? */
463
464	*p++ = 0x47; *p++ = 0x00; *p++ = 0x11;
465	*p++ = ROSE_ADDR_LEN * 2;
466	memcpy(p, &rose->dest_addr, ROSE_ADDR_LEN);
467	p   += ROSE_ADDR_LEN;
468
469	memcpy(p, callsign, strlen(callsign));
470	p   += strlen(callsign);
471
472	*p++ = FAC_CCITT_SRC_NSAP;
473
474	callsign = ax2asc(buf, &rose->source_call);
475
476	*p++ = strlen(callsign) + 10;
477	*p++ = (strlen(callsign) + 9) * 2;		/* ??? */
478
479	*p++ = 0x47; *p++ = 0x00; *p++ = 0x11;
480	*p++ = ROSE_ADDR_LEN * 2;
481	memcpy(p, &rose->source_addr, ROSE_ADDR_LEN);
482	p   += ROSE_ADDR_LEN;
483
484	memcpy(p, callsign, strlen(callsign));
485	p   += strlen(callsign);
486
487	len       = p - buffer;
488	buffer[0] = len - 1;
489
490	return len;
491}
492
493void rose_disconnect(struct sock *sk, int reason, int cause, int diagnostic)
494{
495	struct rose_sock *rose = rose_sk(sk);
496
497	rose_stop_timer(sk);
498	rose_stop_idletimer(sk);
499
500	rose_clear_queues(sk);
501
502	rose->lci   = 0;
503	rose->state = ROSE_STATE_0;
504
505	if (cause != -1)
506		rose->cause = cause;
507
508	if (diagnostic != -1)
509		rose->diagnostic = diagnostic;
510
511	sk->sk_state     = TCP_CLOSE;
512	sk->sk_err       = reason;
513	sk->sk_shutdown |= SEND_SHUTDOWN;
514
515	if (!sock_flag(sk, SOCK_DEAD)) {
516		sk->sk_state_change(sk);
517		sock_set_flag(sk, SOCK_DEAD);
518	}
519}
520