File: dupecheck.c

package info (click to toggle)
aprx 2.9.0+dfsg-2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 2,352 kB
  • sloc: ansic: 15,809; sh: 598; makefile: 160
file content (483 lines) | stat: -rw-r--r-- 12,046 bytes parent folder | download | duplicates (2)
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
/* **************************************************************** *
 *                                                                  *
 *  APRX -- 2nd generation APRS iGate and digi with                 *
 *          minimal requirement of esoteric facilities or           *
 *          libraries of any kind beyond UNIX system libc.          *
 *                                                                  *
 * (c) Matti Aarnio - OH2MQK,  2007-2014                            *
 *                                                                  *
 * **************************************************************** */

#include "aprx.h"

/*
 *	Some parts of this code are copied from:
 *
 *	aprsc
 *
 *	(c) Heikki Hannikainen, OH7LZB <hessu@hes.iki.fi>
 *
 *	This program is licensed under the BSD license, which can be found
 *	in the file LICENSE.
 *	
 */

/*
 *	dupecheck.c: the dupe-checkers
 */

static int           dupecheck_cellgauge;
static int           dupecheckers_count;
static dupecheck_t **dupecheckers;


#ifndef _FOR_VALGRIND_
cellarena_t *dupecheck_cells;
#endif

const int duperecord_size  = sizeof(struct dupe_record_t);
const int duperecord_align = __alignof__(struct dupe_record_t);

/*
 *	The cellmalloc does not need internal MUTEX, it is being used in single thread..
 */

void dupecheck_init(void)
{
#ifndef _FOR_VALGRIND_
	dupecheck_cells = cellinit( "dupecheck",
				    duperecord_size,
				    duperecord_align,
				    CELLMALLOC_POLICY_LIFO | CELLMALLOC_POLICY_NOMUTEX,
				    4 /* 4 kB at the time */,
				    0 /* minfree */);
#endif
}

/*
 * dupecheck_new() creates a new instance of dupechecker
 *
 */
dupecheck_t *dupecheck_new(const int storetime) {
	dupecheck_t *dp = calloc(1, sizeof(dupecheck_t));

	++dupecheckers_count;
	dupecheckers = realloc(dupecheckers,
			       sizeof(dupecheck_t *) * dupecheckers_count);
	dupecheckers[ dupecheckers_count -1 ] = dp;

        dp->storetime = storetime;

	return dp;
}


static dupe_record_t *dupecheck_db_alloc(int alen, int pktlen)
{
	dupe_record_t *dp;
#ifndef _FOR_VALGRIND_
//	if (debug) printf("DUPECHECK db alloc(alen=%d,dlen=%d) %s",
//			  alen,pktlen, dupecheck_free ? "FreeChain":"CellMalloc");

	dp = cellmalloc(dupecheck_cells);
//	if (debug) printf(" dp=%p\n",dp);
	if (dp == NULL)
		return NULL;
	// cellmalloc() block may need separate pktbuf
	memset(dp, 0, sizeof(*dp));
	dp->packet = dp->packetbuf;
	if (pktlen > sizeof(dp->packetbuf))
		dp->packet = malloc(pktlen+1);
#else
	// directly malloced block is fine as is
	dp = calloc(1, pktlen + sizeof(*dp));
	dp->packet = dp->packetbuf; // always suitable size
#endif
	dp->alen = alen;
	dp->plen = pktlen;

	++dupecheck_cellgauge;

	dupecheck_get(dp); // increment refcount

	// if(debug)printf("DUPECHECK db alloc() returning dp=%p\n",dp);
	return dp;
}

static void dupecheck_db_free(dupe_record_t *dp)
{
	if (dp->pbuf != NULL) { // If a pbuf is referred, release it
		pbuf_put(dp->pbuf); // decrements refcount - and frees at zero.
		dp->pbuf = NULL;
	}
#ifndef _FOR_VALGRIND_
	if (dp->packet != dp->packetbuf)
		free(dp->packet);
	cellfree(dupecheck_cells, dp);
#else
	free(dp);
#endif
	--dupecheck_cellgauge;
}

// Increment refcount
dupe_record_t *dupecheck_get(dupe_record_t *dp)
{
	dp->refcount += 1;
	return dp;
}

// Decrement refcount, when zero, call free
void dupecheck_put(dupe_record_t *dp)
{
	dp->refcount -= 1;
	if (dp->refcount <= 0) {
		dupecheck_db_free(dp);
	}
}

/*	The  dupecheck_cleanup() is for regular database cleanups,
 *	Call this about once a minute.
 *
 *	Note: entry validity is possibly shorter time than the cleanup
 *	invocation interval!
 */
static void dupecheck_cleanup(void)
{
	dupe_record_t *dp, **dpp;
	int cleancount = 0, i, d;

	// All dupecheckers..
	for (d = 0; d < dupecheckers_count; ++d) {

	  // Within this dupechecker...
	  struct dupecheck_t *dpc = dupecheckers[d];
	  for (i = 0; i < DUPECHECK_DB_SIZE; ++i) {
	    dpp = & (dpc->dupecheck_db[i]);
	    while (( dp = *dpp )) {
	      if ((dp->t_exp - tick.tv_sec) < 0) {
		/* Old..  discard. */
		*dpp = dp->next;
		dp->next = NULL;
		dupecheck_put(dp);
		++cleancount;
		continue;
	      }
	      /* No expiry, just advance the pointer */
	      dpp = &dp->next;
	    }
	  }
	}
	// hlog( LOG_DEBUG, "dupecheck_cleanup() removed %d entries, count now %ld",
	//       cleancount, dupecheck_cellgauge );
}

/*
 *	Check a single packet for duplicates in APRS sense
 *	The addr/alen must be in TNC2 monitor format, data/dlen
 *      are expected to be APRS payload as well.
 */

dupe_record_t *dupecheck_aprs(dupecheck_t *dpc,
			      const char *addr, const int alen,
			      const char *data, const int dlen)
{
	/* check a single packet */
	// pb->flags |= F_DUPE; /* this is a duplicate! */

	int i;
	int addrlen;  // length of the address part
	int datalen;  // length of the payload
	uint32_t hash, idx;
	dupe_record_t **dpp, *dp;

	// 1) collect canonic rep of the address (SRC,DEST, no VIAs)
	i = 1;
	for (addrlen = 0; addrlen < alen; ++ addrlen) {
		const char c = addr[addrlen];
		if (c == 0 || c == ',' || c == ':') {
			break;
		}
		if (c == '-' && i) {
			i = 0;
		}
	}

        // code to prevent segmentation fault
        if (addrlen > 18) {
          if (debug>1) printf("  addrlen=\"%d\" > 18, discard packet\n",addrlen);
          return NULL;
        }

	// Canonic tail has no SPACEs in data portion!
	// TODO: how to treat 0 bytes ???
	datalen = dlen;
	while (datalen > 0 && data[datalen-1] == ' ')
		--datalen;

	// there are no 3rd-party frames in APRS-IS ...

	// 2) calculate checksum (from disjoint memory areas)

	hash = keyhash(addr, addrlen, 0);
	hash = keyhash(data, datalen, hash);
	idx  = hash;

	// 3) lookup if same checksum is in some hash bucket chain
	//  3b) compare packet...
	//    3b1) flag as F_DUPE if so
	// DUPECHECK_DB_SIZE == 16 -> 4 bits index
	idx ^= (idx >> 16); /* fold the hash bits.. */
	idx ^= (idx >>  8); /* fold the hash bits.. */
	idx ^= (idx >>  4); /* fold the hash bits.. */
	i = idx % DUPECHECK_DB_SIZE;
	dpp = &(dpc->dupecheck_db[i]);
	while (*dpp) {
		dp = *dpp;
		if ((dp->t_exp - tick.tv_sec) < 0) {
			// Old ones are discarded when seen
			*dpp = dp->next;
			dp->next = NULL;
			dupecheck_put(dp);
			continue;
		}
		if (dp->hash == hash) {
			// HASH match!  And not too old!
			if (dp->alen == addrlen &&
			    dp->plen == datalen &&
			    memcmp(addr, dp->addresses, addrlen) == 0 &&
			    memcmp(data, dp->packet,    datalen) == 0) {
				// PACKET MATCH!
				dp->seen += 1;
				return dp;
			}
			// no packet match.. check next
		}
		dpp = &dp->next;
	}
	// dpp points to pointer at the tail of the chain

	// 4) Add comparison copy of non-dupe into dupe-db

	dp = dupecheck_db_alloc(addrlen, datalen);
	if (dp == NULL) return NULL; // alloc error!
	*dpp = dp; // Put it on tail of existing chain


	memcpy(dp->addresses, addr, addrlen);
	memcpy(dp->packet,    data, datalen);

	dp->seen  = 1;  // First observation gets number 1
	dp->hash  = hash;
	dp->t     = tick.tv_sec;
	dp->t_exp = tick.tv_sec + dpc->storetime;
	return NULL;
}


/*
 *  dupecheck_pbuf() returns pointer to dupe record, if pbuf is
 *  a duplicate.  Otherwise it return a NULL.
 */
dupe_record_t *dupecheck_pbuf(dupecheck_t *dpc, struct pbuf_t *pb, const int viscous_delay)
{
	int i;
	uint32_t hash, idx;
	dupe_record_t **dpp, *dp;
	const char *addr = pb->data;
	int   alen = pb->dstcall_end - addr;

	const char *dataend = pb->data + pb->packet_len;
	const char *data    = pb->info_start;
	int   dlen = dataend - data;

	int addrlen = alen;
	int datalen = dlen;
	char *p;

	/* if (debug && pb->is_aprs) {
	  printf("dupecheck[1] addr='");
	  fwrite(addr, alen, 1, stdout);
	  printf("' data='");
	  fwrite(data, dlen, 1, stdout);
	  printf("'\n");
	} */


	// Canonic tail has no SPACEs in data portion!
	// TODO: how to treat 0 bytes ???
	
	if (!pb->is_aprs) {
		// data and dlen are raw AX.25 section pointers
		data    = (const char*) pb->ax25data;
		datalen = pb->ax25datalen;

	} else {  // Do with APRS rules
	    for (;;) {

		// 1) collect canonic rep of the address
		i = 1;
		for (addrlen = 0; addrlen < alen; ++ addrlen) {
			const char c = addr[addrlen];
			if (c == 0 || c == ',' || c == ':') {
				break;
			}
			if (c == '-' && i) {
				i = 0;
			}
		}
		while (datalen > 0 && data[datalen-1] == ' ')
			--datalen;

		if (data[0] == '}') {
			// 3rd party frame!
			addr = data+1;
			p = memchr(addr,':',datalen-1);
			if (p == NULL)
				break; // Invalid 3rd party frame, no ":" in it
			alen = p - addr;
			data = p+1;
			datalen = dataend - data;

			/* if (debug && pb->is_aprs) {
			  printf("dupecheck[2] 3rd-party: addr='");
			  fwrite(addr, alen, 1, stdout);
			  printf("' data='");
			  fwrite(data, datalen, 1, stdout);
			  printf("'\n");
			} */

			continue;  // repeat the processing!
		}
		break; // No repeat necessary in general case
	    }
	}

	// 2) calculate checksum (from disjoint memory areas)

	/* if (debug && pb->is_aprs) {
	  printf("dupecheck[3] addr='");
	  fwrite(addr, addrlen, 1, stdout);
	  printf("' data='");
	  fwrite(data, datalen, 1, stdout);
	  printf("'\n");
	} */

	hash = keyhash(addr, addrlen, 0);
	hash = keyhash(data, datalen, hash);
	idx  = hash;

	/* if (debug>1) {
	     printf("DUPECHECK: Addr='");
	     fwrite(addr, 1, addrlen, stdout);
	     printf("' Data='");
	     fwrite(data, 1, datalen, stdout);
	     printf("'  hash=%x\n", hash);
	   }
	*/

	// 3) lookup if same checksum is in some hash bucket chain
	//  3b) compare packet...
	//    3b1) flag as F_DUPE if so
	// DUPECHECK_DB_SIZE == 16 -> 4 bits index
	idx ^= (idx >> 16); /* fold the hash bits.. */
	idx ^= (idx >>  8); /* fold the hash bits.. */
	idx ^= (idx >>  4); /* fold the hash bits.. */
	i = idx % DUPECHECK_DB_SIZE;
	dpp = &(dpc->dupecheck_db[i]);
	while (*dpp) {
		dp = *dpp;
		if ((dp->t_exp - tick.tv_sec) < 0) {
			// Old ones are discarded when seen
			*dpp = dp->next;
			dp->next = NULL;
			dupecheck_put(dp);
			continue;
		}
		if (dp->hash == hash) {
			// HASH match!  And not too old!
			if (dp->alen == addrlen &&
			    dp->plen == datalen &&
			    memcmp(addr, dp->addresses, addrlen) == 0 &&
			    memcmp(data, dp->packet,    datalen) == 0) {
				// PACKET MATCH!
				if (viscous_delay > 0)
				  dp->delayed_seen += 1;
				else
				  dp->seen += 1;
				return dp;
			}
			// no packet match.. check next
		}
		dpp = &dp->next;
	}
	// dpp points to pointer at the tail of the chain

	// 4) Add comparison copy of non-dupe into dupe-db

	dp = dupecheck_db_alloc(addrlen, datalen);
	if (dp == NULL) {
	  if (debug) printf("DUPECHECK ALLOC ERROR!\n");
	  return NULL; // alloc error!
	}
	*dpp = dp; // Put it on tail of existing chain

	memcpy(dp->addresses, addr, addrlen);
	memcpy(dp->packet,    data, datalen);

	dp->pbuf  = pbuf_get(pb); // increments refcount
	if (viscous_delay > 0) {  // First observation gets number 1
	  dp->seen         = 0;
	  dp->delayed_seen = 1;
	  dp->pbuf         = pb;
	} else {
	  dp->seen         = 1;
	  dp->delayed_seen = 0;
	}

	dp->hash  = hash;
	dp->t     = tick.tv_sec;
	dp->t_exp = tick.tv_sec + dpc->storetime;

	return dp;
}

/*
 * dupechecker aprx poll integration, timed tasks control
 *
 */

static struct timeval dupecheck_cleanup_nexttime;

static void dupecheck_resettime(void *arg)
{
	struct timeval *tv = (struct timeval *)arg;
        *tv = tick;
}

int dupecheck_prepoll(struct aprxpolls *app)
{
	if (time_reset) {
        	dupecheck_resettime(&dupecheck_cleanup_nexttime);
        }

	if (dupecheck_cleanup_nexttime.tv_sec == 0) dupecheck_cleanup_nexttime = tick;

	if (tv_timercmp(&dupecheck_cleanup_nexttime, &app->next_timeout) > 0)
		app->next_timeout = dupecheck_cleanup_nexttime;

	return 0;		/* No poll descriptors, only time.. */
}


int dupecheck_postpoll(struct aprxpolls *app)
{
        if (tv_timercmp(&dupecheck_cleanup_nexttime, &tick) > 0)
		return 0;	/* Too early.. */

        tv_timeradd_seconds( &dupecheck_cleanup_nexttime, &tick, 30 ); // tick every 30 second or so

	dupecheck_cleanup();

	return 0;
}