summaryrefslogtreecommitdiffstats
path: root/netrom/nrsdrv.c
blob: 92b3d6aa91b27be3cb6d715f5c2952d770a0835e (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
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <termios.h>
#include <fcntl.h>
#include <signal.h>
#include <ctype.h>
#include <netdb.h>
#include <syslog.h>

#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>

#include <sys/socket.h>
#include <netax25/daemon.h>
#include <netax25/ttyutils.h>

#include <config.h>

#include "../pathnames.h"

static int kissfd, nrsfd;
static int logging = FALSE;
static int debugging = FALSE;
static int flowcontrol = FALSE;
static char *kissdev, *nrsdev;

#define	NUL		000
#define	STX		002
#define	ETX		003
#define	DLE		020

#define	NRS_WAIT	0
#define	NRS_DATA	1
#define	NRS_ESCAPE	2
#define	NRS_CKSUM	3
static int nrs_state = NRS_WAIT;

static unsigned char nrs_cksum = 0;

static unsigned char nrs_rxbuffer[512];
static int nrs_rxcount = 0;

#define	FEND		0300
#define	FESC		0333
#define	FESCEND		0334
#define	FESCESC		0335

#define	KISS_WAIT	0
#define	KISS_CTRL	1
#define	KISS_DATA	2
#define	KISS_ESCAPE	3
static int kiss_state = KISS_WAIT;

static unsigned char kiss_rxbuffer[512];
static int kiss_rxcount = 0;

static void terminate(int sig)
{
	if (logging) {
		syslog(LOG_INFO, "terminating on SIGTERM\n");
		closelog();
	}

	tty_unlock(kissdev);
	tty_unlock(nrsdev);

	exit(0);
}

static void key_rts(int fd)
{
	int status;

	if (!flowcontrol)
		return;

	/* Wait for CTS to be low */
	while (1) {
		/* Get CTS status */
                if (ioctl(fd, TIOCMGET, &status) < 0) {
			syslog(LOG_INFO|LOG_ERR, "TIOCMGET failed: flowcontrol disabled (%m)\n");
			flowcontrol = 0;
                        return;
                }
		if (status & TIOCM_CTS) {
			if (debugging) {
				fprintf(stderr,"CTS high: waiting\n");
			}
                	ioctl(fd, TIOCMIWAIT, &status);
		} else {
			break;
		}
	}

	if (debugging) {
		fprintf(stderr,"CTS low: keying RTS\n");
	}
	status |= TIOCM_RTS | TIOCM_DTR;
        if (ioctl(fd, TIOCMSET, &status) < 0) {
		syslog(LOG_INFO|LOG_ERR, "TIOCMGET failed: flowcontrol disabled (%m)\n");
		flowcontrol = 0;
        }
}

static void unkey_rts(int fd)
{
	int status;

	if (!flowcontrol)
		return;

	if (debugging) {
		fprintf(stderr,"Transmission finished: unkeying RTS\n");
	}
        ioctl(fd, TIOCMGET, &status);
	status &= ~TIOCM_RTS;
        status |= TIOCM_DTR;
        if (ioctl(fd, TIOCMSET, &status) < 0) {
		syslog(LOG_INFO|LOG_ERR, "TIOCMGET failed: flowcontrol disabled (%m)\n");
		flowcontrol = 0;
        }
}

static void nrs_esc(unsigned char *s, int len)
{
	static unsigned char buffer[512];
	unsigned char *ptr = buffer;
	unsigned char csum = 0;
	unsigned char c;

	*ptr++ = STX;

	while (len-- > 0) {
		switch (c = *s++) {
			case STX:
			case ETX:
			case DLE:
				*ptr++ = DLE;
				/* Fall through */
			default:
				*ptr++ = c;
				break;
		}
		
		csum += c;
	}

	*ptr++ = ETX;
	*ptr++ = csum;
	*ptr++ = NUL;
	*ptr++ = NUL;

	key_rts(nrsfd);
	write(nrsfd, buffer, ptr - buffer);
	unkey_rts(nrsfd);
}

static void kiss_esc(unsigned char *s, int len)
{
	static unsigned char buffer[512];
	unsigned char *ptr = buffer;
	unsigned char c;

	*ptr++ = FEND;
	*ptr++ = 0x00;		/* KISS DATA */

	while (len-- > 0) {
		switch (c = *s++) {
			case FESC:
				*ptr++ = FESC;
				*ptr++ = FESCESC;
				break;
			case FEND:
				*ptr++ = FESC;
				*ptr++ = FESCEND;
				break;
			default:
				*ptr++ = c;
				break;
		}
	}

	*ptr++ = FEND;

	write(kissfd, buffer, ptr - buffer);
}

static void nrs_unesc(unsigned char *buffer, int len)
{
	int i;
	
	for (i = 0; i < len; i++) {
		switch (nrs_state) {
			case NRS_WAIT:
				if (buffer[i] == STX) {
					nrs_state   = NRS_DATA;
					nrs_rxcount = 0;
					nrs_cksum   = 0;
				}
				break;

			case NRS_DATA:
				switch (buffer[i]) {	
					case STX:	/* !! */
						nrs_rxcount = 0;
						nrs_cksum   = 0;
						break;
					case DLE:
						nrs_state = NRS_ESCAPE;
						break;
					case ETX:
						nrs_state = NRS_CKSUM;
						break;
					default:
						if (nrs_rxcount < 512) {
							nrs_cksum += buffer[i];
							nrs_rxbuffer[nrs_rxcount++] = buffer[i];
						}
						break;
				}
				break;

			case NRS_ESCAPE:
				nrs_state = NRS_DATA; 
				if (nrs_rxcount < 512) {
					nrs_cksum += buffer[i];
					nrs_rxbuffer[nrs_rxcount++] = buffer[i];
				}
				break;

			case NRS_CKSUM:
				if (buffer[i] == nrs_cksum)
					kiss_esc(nrs_rxbuffer, nrs_rxcount);
				nrs_state   = NRS_WAIT;
				nrs_cksum   = 0;
				nrs_rxcount = 0;
				break;
		}
	}
}

static void kiss_unesc(unsigned char *buffer, int len)
{
	int i;
	
	for (i = 0; i < len; i++) {
		switch (kiss_state) {
			case KISS_WAIT:
				if (buffer[i] == FEND) {
					kiss_state   = KISS_CTRL;
					kiss_rxcount = 0;
				}
				break;

			case KISS_CTRL:
				if ((buffer[i] & 0x0F) == 0x00) {
					kiss_state   = KISS_DATA;
					kiss_rxcount = 0;
				} else {
					kiss_state   = KISS_WAIT;
					kiss_rxcount = 0;
				}
				break;

			case KISS_DATA:
				switch (buffer[i]) {	
					case FEND:
						if (kiss_rxcount > 2)
							nrs_esc(kiss_rxbuffer, kiss_rxcount);
						kiss_state   = KISS_WAIT;
						kiss_rxcount = 0;
						break;
					case FESC:
						kiss_state = KISS_ESCAPE;
						break;
					default:
						if (kiss_rxcount < 512)
							kiss_rxbuffer[kiss_rxcount++] = buffer[i];
						break;
				}
				break;

			case KISS_ESCAPE:
				kiss_state = KISS_DATA;
				switch (buffer[i]) {
					case FESCESC:
						if (kiss_rxcount < 512)
							kiss_rxbuffer[kiss_rxcount++] = FESC;
						break;
					case FESCEND:
						if (kiss_rxcount < 512)
							kiss_rxbuffer[kiss_rxcount++] = FEND;
						break;
				}
				break;
		}
	}
}

int main(int argc, char *argv[])
{
	static char buffer[512];
	unsigned int speed = 0;
	fd_set read_fd;
	int c, n;

	while ((c = getopt(argc, argv, "dfls:v")) != -1) {
		switch (c) {
			case 'd':
				debugging = TRUE;
				break;
			case 'f':
				flowcontrol = TRUE;
				break;
			case 'l':
				logging = TRUE;
				break;
			case 's':
				if ((speed = atoi(optarg)) <= 0) {
					fprintf(stderr, "nrsdrv: invalid speed %s\n", optarg);
					return 1;
				}
				break;
			case 'v':
				printf("kissattach: %s\n", VERSION);
				return 0;
			case ':':
			case '?':
				fprintf(stderr, "usage: nrsdrv [-f] [-l] [-s speed] [-v] kisstty nrstty\n");
				return 1;
		}
	}

	if (debugging) {
		fprintf(stderr,"Flow control %s\n", 
			flowcontrol ? "enabled" : "disabled");
	}

	if ((argc - optind) != 2) {
		fprintf(stderr, "usage: nrsdrv [-f] [-l] [-s speed] [-v] kisstty nrstty\n");
		return 1;
	}

	kissdev = argv[optind + 0];
	nrsdev  = argv[optind + 1];

	if (tty_is_locked(kissdev)) {
		fprintf(stderr, "nrsdrv: device %s already in use\n", argv[optind]);
		return 1;
	}

	if (tty_is_locked(nrsdev)) {
		fprintf(stderr, "nrsdrv: device %s already in use\n", argv[optind + 1]);
		return 1;
	}

	if ((kissfd = open(kissdev, O_RDWR)) == -1) {
		perror("nrsdrv: open kiss device");
		return 1;
	}

	if ((nrsfd = open(nrsdev, O_RDWR)) == -1) {
		perror("nrsdrv: open nrs device");
		return 1;
	}

	tty_lock(kissdev);
	tty_lock(nrsdev);

	if (!tty_raw(kissfd, FALSE)) {
		tty_unlock(kissdev);
		tty_unlock(nrsdev);
		return 1;
	}

	if (!tty_raw(nrsfd, FALSE)) {
		tty_unlock(kissdev);
		tty_unlock(nrsdev);
		return 1;
	}

	if (speed != 0 && !tty_speed(kissfd, speed)) {
		tty_unlock(kissdev);
		tty_unlock(nrsdev);
		return 1;
	}

	if (speed != 0 && !tty_speed(nrsfd, speed)) {
		tty_unlock(kissdev);
		tty_unlock(nrsdev);
		return 1;
	}

	if (logging) {
		openlog("nrsdrv", LOG_PID, LOG_DAEMON);
		syslog(LOG_INFO, "KISS device %s connected to NRS device %s\n", argv[optind + 0], argv[optind + 1]);
	}
		
	signal(SIGHUP, SIG_IGN);
	signal(SIGTERM, terminate);

	/*
	 * Become a daemon if we can.
	 */
	if (!daemon_start(FALSE)) {
		fprintf(stderr, "nrsdrv: cannot become a daemon\n");
		tty_unlock(kissdev);
		tty_unlock(nrsdev);
		return 1;
	}

	if (flowcontrol) {
		unkey_rts(nrsfd);
	}

	c = ((kissfd > nrsfd) ? kissfd : nrsfd) + 1;

	for (;;) {
		FD_ZERO(&read_fd);
		
		FD_SET(kissfd, &read_fd);
		FD_SET(nrsfd, &read_fd);

		n = select(c, &read_fd, NULL, NULL, NULL);

		if (FD_ISSET(kissfd, &read_fd)) {
			if ((n = read(kissfd, buffer, 512)) <= 0) {
				if (logging) {
					syslog(LOG_INFO, "terminating on KISS device closure\n");
					closelog();
				}
				break;
			}
			kiss_unesc(buffer, n);
		}
		
		if (FD_ISSET(nrsfd, &read_fd)) {
			if ((n = read(nrsfd, buffer, 512)) <= 0) {
				if (logging) {
					syslog(LOG_INFO, "terminating on NRS device closure\n");
					closelog();
				}
				break;
			}
			nrs_unesc(buffer, n);
		}
	}

	tty_unlock(kissdev);
	tty_unlock(nrsdev);

	return 0;
}