/* **************************************************************** *
 *                                                                  *
 *  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"

static int digi_count;
static struct digipeater **digis;

#define TOKENBUCKET_INTERVAL 5  // 5 seconds per refill.
                                // 60/5 part of "ratelimit" to be max
                                // that token bucket can be filled to.

static struct timeval tokenbucket_timer;

struct viastate {
	int hopsreq;
	int hopsdone;
	int tracereq;
	int tracedone;
	int digireq;
	int digidone;

	int fixthis;
	int fixall;
	int probably_heard_direct;
};

struct digistate {
	struct viastate v;

	int     ax25addrlen;
	uint8_t ax25addr[90]; // 70 for address, a bit more for "body"
};


#define AX25ADDRMAXLEN 70  // SRC + DEST + 8*VIA (7 bytes each)
#define AX25ADDRLEN  7
#define AX25HBIT  0x80
#define AX25ATERM 0x01

static char * tracewords[] = { "WIDE","TRACE","RELAY" };
static int tracewordlens[] = { 4, 5, 5 };
static const struct tracewide default_trace_param = {
	4, 4, 1, // maxreq, maxdone, is_trace
	3, // Count of tracewords defined above
	tracewords,
	tracewordlens
};
static char * widewords[] = { "WIDE","RELAY" };
static int widewordlens[] = { 4,5 };
static const struct tracewide default_wide_param = {
	4, 4, 0,
	2,
	widewords,
	widewordlens
};

static int  run_tokenbucket_timers(void);


float ratelimitmax     = 9999999.9;
float rateincrementmax = 9999999.9;


/*
 * regex_filter_add() -- adds configured regular expressions
 *                       into forbidden patterns list.
 * 
 * These are actually processed on TNC2 format text line, and not
 * AX.25 datastream per se.
 */
static int regex_filter_add(struct configfile *cf,
		struct digipeater_source *src,
		char *param1,
		char *str)
{
	int rc;
	int groupcode = -1;
	regex_t re, *rep;
	char errbuf[2000];

	if (strcmp(param1, "source") == 0) {
		groupcode = 0;
	} else if (strcmp(param1, "destination") == 0) {
		groupcode = 1;
	} else if (strcmp(param1, "via") == 0) {
		groupcode = 2;
	} else if (strcmp(param1, "data") == 0) {
		groupcode = 3;
	} else {
		printf("%s:%d ERROR: Bad RE target: '%s'  must be one of: source, destination, via\n",
				cf->name, cf->linenum, param1);
		return 1;
	}

	if (!*str) {
		printf("%s:%d ERROR: Expected RE pattern missing or a NUL string.\n",
				cf->name, cf->linenum);
		return 1;               /* Bad input.. */
	}

	param1 = str;
	str = config_SKIPTEXT(str, NULL); // Handle quoted string
	str = config_SKIPSPACE(str);

	memset(&re, 0, sizeof(re));
	rc = regcomp(&re, param1, REG_EXTENDED | REG_NOSUB);

	if (rc != 0) {          /* Something is bad.. */
		*errbuf = 0;
		regerror(rc, &re, errbuf, sizeof(errbuf));
		printf("%s:%d ERROR: Bad POSIX RE input, error: %s\n",
				cf->name, cf->linenum, errbuf);
		return 1;
	}

	/* param1 and str were processed successfully ... */

	rep = calloc(1,sizeof(*rep));
	*rep = re;

	switch (groupcode) {
		case 0:
			src->sourceregscount += 1;
			src->sourceregs = realloc(src->sourceregs,
						src->sourceregscount * sizeof(void *));
			src->sourceregs[src->sourceregscount - 1] = rep;
			break;
		case 1:
			src->destinationregscount += 1;
			src->destinationregs = realloc(src->destinationregs,
						src->destinationregscount * sizeof(void *));
			src->destinationregs[src->destinationregscount - 1] = rep;
			break;
		case 2:
			src->viaregscount += 1;
			src->viaregs = realloc(src->viaregs,
					src->viaregscount * sizeof(void *));
			src->viaregs[src->viaregscount - 1] = rep;
			break;
		case 3:
			src->dataregscount += 1;
			src->dataregs = realloc(src->dataregs,
						src->dataregscount * sizeof(void *));
			src->dataregs[src->dataregscount - 1] = rep;
			break;
	}
	return 0; // OK state
}


static int match_tracewide(const char *via, const struct tracewide *twp)
{
	int i;
	if (twp == NULL) return 0;

	for (i = 0; i < twp->nkeys; ++i) {
		// if (debug>2) printf(" match:'%s'",twp->keys[i]);
		if (memcmp(via, twp->keys[i], twp->keylens[i]) == 0) {
			return twp->keylens[i];
		}
	}
	return 0;
}

static int match_aliases(const char *via, struct aprx_interface *txif)
{
	int i;
	for (i = 0; i < txif->aliascount; ++i) {
		if (strcmp(via, txif->aliases[i]) == 0)
			return 1;
	}
	return 0;
}

// Counts the number of requested and consumed hops in an alias
// and adds those to the viastate->{digireq,digidone,tracereq,tracedone}.
// returns 1 on horrific failure
static int count_single_tnc2_tracewide(struct viastate *state,
		const char *viafield, const int istrace,
		const int matchlen, const int viaindex)
{
	const char *p = viafield + matchlen;
	const char reqc = p[0];
	const char c    = p[1];
	const char remc = p[2];
	int req, done;

	int hasHflag = (strchr(viafield,'*') != NULL);

	// Non-matched case, may have H-bit flag
	if (matchlen == 0) {
		req  = 1;
		done = hasHflag;
		if (viaindex == 2 && !hasHflag)
			state->probably_heard_direct = 1;
		// if (debug>1) printf(" a[req=%d,done=%d,trace=%d]",0,0,hasHflag);
		goto addtostate;
	}

	// Is the character following matched part not [1-7]
	if (!('1' <= reqc && reqc <= '7')) {
		// Not a digit, this is single matcher..
		req = 1;
		done = hasHflag;

		if (viaindex == 2 && !hasHflag)
			state->probably_heard_direct = 1;
		// if (debug>1) printf(" d[req=%d,done=%d]",1,hasHflag);
		goto addtostate;
	}

	req = reqc - '0';

	if (c == '*' && remc == 0) { // WIDE1*
		done = req;
		// if (debug>1) printf(" e[req=%d,done=%d]",req,req);
		goto addtostate;
	}
	if (c == 0) { // Bogus WIDE1 - uidigi puts these out.
		state->fixthis = 1;
		done = req;
		// if (debug>1) printf(" E[req=%d,done=%d]",req,req);
		goto addtostate;
	}
	// Not WIDE1-
	if (c != '-') {
		req = 1;
		done = hasHflag;
		// if (debug>1) printf(" f[req=%d,done=%d]",1,hasHflag);
		goto addtostate;
	}

	// OK, it is "WIDEn-" plus "N"
	if ('0' <= remc  && remc <= '7' && p[3] == 0) {
		done = req - (remc - '0');
		if (done < 0) {
			// Something like "WIDE3-7", which is definitely bogus!
			done = 0;
			state->fixall = 1;
			if (viaindex == 2 && !hasHflag)
				state->probably_heard_direct = 1;
			goto addtostate;
		}
		if (viaindex == 2) {
			if (istrace) // A real "TRACE" in first slot?
				state->probably_heard_direct = 1;

			else if (!hasHflag && done == 0) // WIDE1-1/2-2/3-3/etc on first slot
				state->probably_heard_direct = 1;
		}
		// if (debug>1) printf(" g[req=%d,done=%d%s]",req,done,hasHflag ? ",Hflag!":"");
		goto addtostate;

	} else if (('8' <= remc && remc <= '9' && p[3] == 0) ||
			(remc == '1' && '0' <= p[3] && p[3] <= '5' && p[4] == 0)) {
		// The request has SSID value in range of 8 to 15
		state->fixall = 1;
		if (viaindex == 2 && !hasHflag)
			state->probably_heard_direct = 1;
		return 0;

	} else {
		// Yuck, impossible/syntactically invalid
		state->hopsreq  += 1;
		state->hopsdone += hasHflag;
		if (istrace) {
			state->tracereq  += 1;
			state->tracedone += hasHflag;
		}
		if (viaindex == 2 && !hasHflag)
			state->probably_heard_direct = 1;
		// if (debug>1) printf(" h[req=%d,done=%d]",1,hasHflag);
		return 1;
	}

addtostate:;
		 // We've successfully parsed the field. Update the viastate and return 0
		 state->hopsreq  += req;
		 state->hopsdone += done;
		 if (istrace) {
			 state->tracereq  += req;
			 state->tracedone += done;
		 }
		 return 0;
}

static int match_transmitter(const char *viafield,
		const struct digipeater_source *src,
		const int lastviachar)
{
	struct aprx_interface *aif = src->parent->transmitter;
	int tlen = strlen(aif->callsign);

	if (memcmp(viafield, aif->callsign, tlen) == 0) {
		if (viafield[tlen] == lastviachar)
			return 1;
	}

	return 0;
}

static int try_reject_filters(const int  fieldtype,
		const char *field,
		struct digipeater_source *src)
{
	int i;
	int stat = 0;
	switch (fieldtype) {
		case 0: // Source
			for (i = 0; i < src->sourceregscount; ++i) {
				stat = regexec(src->sourceregs[i],
						field, 0, NULL, 0);
				if (stat == 0)
					return 1;       /* MATCH! */
			}
			if (memcmp("MYCALL",field,6)==0) return 1;
			if (memcmp("N0CALL",field,6)==0) return 1;
			if (memcmp("NOCALL",field,6)==0) return 1;
			break;
		case 1: // Destination

			for (i = 0; i < src->destinationregscount; ++i) {
				int stat = regexec(src->destinationregs[i],
						field, 0, NULL, 0);
				if (stat == 0)
					return 1;       /* MATCH! */
			}
			if (memcmp("MYCALL",field,6)==0) return 1;
			if (memcmp("N0CALL",field,6)==0) return 1;
			if (memcmp("NOCALL",field,6)==0) return 1;
			break;
		case 2: // Via

			for (i = 0; i < src->viaregscount; ++i) {
				int stat = regexec(src->viaregs[i],
						field, 0, NULL, 0);
				if (stat == 0)
					return 1;       /* MATCH! */
			}
			if (memcmp("MYCALL",field,6)==0) return 1;
			if (memcmp("N0CALL",field,6)==0) return 1;
			if (memcmp("NOCALL",field,6)==0) return 1;
			break;
		case 3: // Data

			for (i = 0; i < src->dataregscount; ++i) {
				int stat = regexec(src->dataregs[i],
						field, 0, NULL, 0);
				if (stat == 0)
					return 1;       /* MATCH! */
			}
			break;
		default:
			if (debug)
				printf("try_reject_filters(fieldtype=%d) - CODE BUG\n",
						fieldtype);
			return 1;
	}
	if (stat != 0 && stat != REG_NOMATCH) {
		// Some odd reason for an error?

	}
	return 0;
}

/* Parse executed and requested WIDEn-N/TRACEn-N info */
static int parse_tnc2_hops(struct digistate *state,
		struct digipeater_source *src,
		struct pbuf_t *pb)
{
	const char *p = pb->dstcall_end+1;
	const char *s;
	const struct digipeater *digi = src->parent;
	const char *lastviastar;
	char viafield[15]; // temp buffer for many uses
	int have_fault = 0;
	int viaindex = 1; // First via index will be 2..
	int activeviacount = 0;
	int len;
	int digiok;

	if (debug>1) printf(" hops count of buffer: %s\n",p);

	if (src->src_relaytype == DIGIRELAY_THIRDPARTY) {
		state->v.hopsreq = 1; // Bonus for tx-igated 3rd-party frames
		state->v.tracereq = 1; // Bonus for tx-igated 3rd-party frames
		state->v.hopsdone = 0;
		state->v.tracedone = 0;
		state->v.probably_heard_direct = 1;
		return 0;
	}

	// Copy the SRCCALL part of  SRCALL>DSTCALL  to viafield[] buffer
	len = pb->srccall_end - pb->data;
	if (len >= sizeof(viafield)) len = sizeof(viafield)-1;
	memcpy(viafield, pb->data, len);
	viafield[len] = 0;
	// if (debug>2)printf(" srccall='%s'",viafield);
	if (try_reject_filters(0, viafield, src)) {
		if (debug>1) printf(" - Src filters reject\n");
		return 1; // Src reject filters
	}

	// Copy the DSTCALL part of  SRCALL>DSTCALL  to viafield[] buffer
	len = pb->dstcall_end - pb->srccall_end -1;
	if (len >= sizeof(viafield)) len = sizeof(viafield)-1;
	memcpy(viafield, pb->srccall_end+1, len);
	viafield[len] = 0;
	// if (debug>2)printf(" destcall='%s'",viafield);
	if (try_reject_filters(1, viafield, src)) {
		if (debug>1) printf(" - Dest filters reject\n");
		return 1; // Dest reject filters
	}

	// Where is the last via-field with a star on it?
	len = pb->info_start - p; if (len < 0) len=0;
	lastviastar = memrchr(p, len, '*');

	// Loop over VIA fields to see if we need to digipeat anything.
	while (p < pb->info_start && !have_fault) {
		len = 0;

		if (*p == ':') {
			// A round may stop at ':' found at the end of the processed field,
			// then next round finds it at the start of the field.
			break;
		}

		// Scan for a VIA field ...
		for (s = p; s < pb->info_start; ++s) {
			if (*s == ',' || *s == ':') {
				// ... until comma or double-colon.
				break;
			}
		}
		// [p..s) is now one VIA field.
		if (s == p && *p != ':') {  // BAD!
			have_fault = 1;
			if (debug>1) printf(" S==P ");
			break;
		}
		if (*p == 'q') break; // APRSIS q-constructs..
		++viaindex;

		// Pick-up a viafield to separate buffer for processing
		len = s-p;
		if (len >= sizeof(viafield)) len = sizeof(viafield)-2;
		memcpy(viafield, p, len);
		viafield[len] = 0;
		if (*s == ',') ++s;
		p = s;

		// Only last via field with H-bit is indicated at TNC2 format,
		// but this digi code logic needs it at every VIA field where
		// it is set.  Therefore this crooked way to add it to picked
		// up fields.
		if (strchr(viafield,'*') == NULL) {
			// If it exists somewhere, and we are not yet at it..
			if (lastviastar != NULL && p < lastviastar)
				strcat(viafield,"*"); // we do know that there is space for this.
		}

		if (debug>1) printf(" - ViaField[%d]: '%s'\n", viaindex, viafield);

		// VIA-field picked up, now analyze it..

		if (try_reject_filters(2, viafield, src)) {
			if (debug>1) printf(" - Via filters reject\n");
			return 1; // via reject filters
		}

		// Transmitter callsign match with H-flag set.
		if (match_transmitter(viafield, src, '*')) {
			if (debug>1) printf(" - Tx match reject\n");
			// Oops, LOOP!  I have transmit this in past
			// (according to my transmitter callsign present
			// in a VIA field!)
			return 1;
		}

		// If there is no '*' meaning this has not been
		// processed, then this is active field..
		if (strchr(viafield, '*') == NULL)
			++activeviacount;

		digiok = 0;

		// If first active field (without '*') matches
		// transmitter or alias, then this digi is accepted
		// regardless if it is APRS or some other protocol.
		if (activeviacount == 1 &&
				(match_transmitter(viafield, src, 0) ||
				 match_aliases(viafield, digi->transmitter))) {
			if (debug>1) printf(" - Tx match accept!\n");
			state->v.hopsreq  += 1;
			state->v.tracereq += 1;
			digiok = 1;
		}

		// .. otherwise following rules are applied only to APRS packets.
		if (pb->is_aprs) {

			if ((len = match_tracewide(viafield, src->src_trace))) {
				// Match source specific list of trace aliases
				if (debug>1) printf("Trace (src specific)\n");
				have_fault = count_single_tnc2_tracewide(&state->v, viafield, 1, len, viaindex);
				if (!have_fault)
					digiok = 1;
			} else if ((len = match_tracewide(viafield, digi->trace))) {
				// Match digipeater-wide list of trace aliases
				if (debug>1) printf("Trace (global)\n");
				have_fault = count_single_tnc2_tracewide(&state->v, viafield, 1, len, viaindex);
				if (!have_fault)
					digiok = 1;
			} else if ((len = match_tracewide(viafield, src->src_wide))) {
				// Match source specific list of non-trace aliases
				if (debug>1) printf("Trace (src-specific, non-trace)\n");
				have_fault = count_single_tnc2_tracewide(&state->v, viafield, 0, len, viaindex);
				if (!have_fault)
					digiok = 1;
			} else if ((len = match_tracewide(viafield, digi->wide))) {
				// Match digipeater-wide list of non-trace aliases
				if (debug>1) printf("Trace (global, non-trace)\n");
				have_fault = count_single_tnc2_tracewide(&state->v, viafield, 0, len, viaindex);
				if (!have_fault)
					digiok = 1;
			} else {
				// No match on trace or wide, but if there was earlier
				// match on interface or alias, then it set "digiok" for us.
				state->v.digidone += (int) (strchr(viafield,'*') != NULL);
				if (debug>1) printf("Trace (non-alias) digi=%d\n",state->v.digidone);
			}
		}
		if (state->v.fixthis || state->v.fixall) {
			// Argh..  bogus WIDEn seen, which is what UIDIGIs put out..
			// Also some other broken requests are "fixed": like WIDE3-7
			// Fixing it: We set the missing H-bit, and continue processing.
			// (That fixing is done in incoming AX25 address field, which
			//  we generally do not touch - with this exception.)
			pb->ax25addr[ AX25ADDRLEN*viaindex + AX25ADDRLEN-1 ] |= AX25HBIT;
			state->v.fixthis = 0;
		}

		if (digiok) {
			if (debug>1) printf(" via field match %s\n", viafield);
			if(state->v.hopsreq>state->v.hopsdone) break;
		}
	}
	return have_fault;
}


static void free_tracewide(struct tracewide *twp)
{
	int i;

	if (twp == NULL) return;
	if (twp->keys) {
		for (i = 0; i < twp->nkeys; ++i)
			free((void*)(twp->keys[i]));
		free(twp->keys);
	}
	if (twp->keylens)
		free((void*)(twp->keylens));

	free(twp);
}
static void free_source(struct digipeater_source *src)
{
	if (src == NULL) return;
	free(src);
}

static struct tracewide *digipeater_config_tracewide(struct configfile *cf, int is_trace)
{
	char  *name, *param1;
	char  *str       = cf->buf;
	int    has_fault = 0;
	int    nkeys     = 0;
	char **keywords  = NULL;
	int   *keylens   = NULL;
	int    maxreq    = 4;
	int    maxdone   = 4;
	struct tracewide *tw;

	while (readconfigline(cf) != NULL) {
		if (configline_is_comment(cf))
			continue;       /* Comment line, or empty line */

		// It can be severely indented...
		str = config_SKIPSPACE(cf->buf);

		name = str;
		str = config_SKIPTEXT(str, NULL);
		str = config_SKIPSPACE(str);
		config_STRLOWER(name);

		param1 = str;
		str = config_SKIPTEXT(str, NULL);
		str = config_SKIPSPACE(str);

		if (is_trace) {
			if (strcmp(name, "</trace>") == 0) {
				break;
			}
		} else {
			if (strcmp(name, "</wide>") == 0) {
				break;
			}
		}

		// ... actual parameters
		if (strcmp(name,"maxreq") == 0) {
			maxreq = atoi(param1);
			// if (debug) printf(" maxreq %d\n",maxreq);

		} else if (strcmp(name,"maxdone") == 0) {
			maxdone = atoi(param1);
			// if (debug) printf(" maxdone %d\n",maxdone);

		} else if (strcmp(name,"keys") == 0) {
			char *k = strtok(param1, ",");
			for (; k ; k = strtok(NULL,",")) {
				++nkeys;
				// if (debug) printf(" n=%d key='%s'\n",nkeys,k);
				keywords = realloc(keywords, sizeof(char*) * nkeys);
				keywords[nkeys-1] = strdup(k);

				keylens  = realloc(keylens,  sizeof(int) * nkeys);
				keylens[nkeys-1] = strlen(k);
			}

		} else {
			has_fault = 1;
			printf("%s:%d ERROR: Unknown keyword inside %s subblock: '%s'\n",
					cf->name, cf->linenum, is_trace ? "<trace>":"<wide>", name);
		}
	}

	if (has_fault) {
		int i;
		for (i = 0; i < nkeys; ++i)
			free(keywords[i]);
		if (keywords != NULL)
			free(keywords);
		if (keylens != NULL)
			free(keylens);
		return NULL;
	}

	tw = calloc(1,sizeof(*tw));

	tw->maxreq   = maxreq;
	tw->maxdone  = maxdone;
	tw->is_trace = is_trace;
	tw->nkeys    = nkeys;
	tw->keys     = keywords;
	tw->keylens  = keylens;

	return tw;
}

static struct digipeater_source *digipeater_config_source(struct configfile *cf)
{
	char *name, *param1;
	char *str = cf->buf;
	int has_fault = 0;
	int viscous_delay = 0;
	float ratelimit = 120;
	float rateincrement = 60;

	struct aprx_interface *source_aif = NULL;
	struct digipeater_source  *source = NULL;
	digi_relaytype          relaytype = DIGIRELAY_DIGIPEAT;
	struct filter_t          *filters = NULL;
	struct tracewide    *source_trace = NULL;
	struct tracewide     *source_wide = NULL;
	struct digipeater_source regexsrc;
#ifndef DISABLE_IGATE
	char                    *via_path = NULL;
	char                    *msg_path = NULL;
	uint8_t               ax25viapath[AX25ADDRLEN];
	uint8_t                msgviapath[AX25ADDRLEN];
#endif

	memset(&regexsrc, 0, sizeof(regexsrc));
#ifndef DISABLE_IGATE
	memset(ax25viapath, 0, sizeof(ax25viapath));
	memset(msgviapath,  0, sizeof(msgviapath));
#endif

	while (readconfigline(cf) != NULL) {
		if (configline_is_comment(cf))
			continue;       /* Comment line, or empty line */

		// It can be severely indented...
		str = config_SKIPSPACE(cf->buf);

		name = str;
		str = config_SKIPTEXT(str, NULL);
		str = config_SKIPSPACE(str);
		config_STRLOWER(name);

		param1 = str;
		str = config_SKIPTEXT(str, NULL);
		str = config_SKIPSPACE(str);

		if (strcmp(name, "</source>") == 0) {
			break;

			// ... actual parameters
		} else if (strcmp(name,"source") == 0) {
			if (debug)
				printf("%s:%d <source> source = '%s'\n",
						cf->name, cf->linenum, param1);

			if (strcasecmp(param1,"$mycall") == 0)
				param1 = (char*)mycall;

			source_aif = find_interface_by_callsign(param1);
			if (source_aif == NULL) {
				has_fault = 1;
				printf("%s:%d ERROR: Digipeater source '%s' not found\n",
						cf->name, cf->linenum, param1);
			}
			if (debug>1)
				printf(" .. source_aif = %p\n", source_aif);

		} else if (strcmp(name, "viscous-delay") == 0) {
			viscous_delay = atoi(param1);
			if (debug) printf(" viscous-delay = %d\n",viscous_delay);
			if (viscous_delay < 0) {
				printf("%s:%d ERROR: Bad value for viscous-delay: '%s'\n",
						cf->name, cf->linenum, param1);
				viscous_delay = 0;
				has_fault = 1;
			}
			if (viscous_delay > 9) {
				printf("%s:%d ERROR: Too large value for viscous-delay: '%s'\n",
						cf->name, cf->linenum, param1);
				viscous_delay = 9;
				has_fault = 1;
			}

		} else if (strcmp(name, "ratelimit") == 0) {
			char *param2 = str;
			str = config_SKIPTEXT(str, NULL);
			str = config_SKIPSPACE(str);

			rateincrement = (float)atof(param1);
			ratelimit     = (float)atof(param2);
			if (rateincrement < 0.01 || rateincrement > rateincrementmax)
				rateincrement = 60;
			if (ratelimit < 0.01 || ratelimit > ratelimitmax)
				ratelimit = 120;
			if (ratelimit < rateincrement)
				rateincrement = ratelimit;
			if (debug)
				printf("  .. ratelimit %f %f\n",
						rateincrement, ratelimit);

		} else if (strcmp(name,"regex-filter") == 0) {
			if (regex_filter_add(cf, &regexsrc, param1, str)) {
				// prints errors internally
				has_fault = 1;
			}

#ifndef DISABLE_IGATE
		} else if (strcmp(name, "via-path") == 0) {

			// Validate that source callsign is "APRSIS"
			// or "DPRS" for this parameter

			if (source_aif == NULL ||
					(strcmp(source_aif->callsign,"APRSIS") != 0 &&
					 strcmp(source_aif->callsign,"DPRS") != 0)) {
				printf("%s:%d ERROR: via-path parameter is available only on 'source APRSIS' and 'source DPRS' cases.\n",
						cf->name, cf->linenum);
				has_fault = 1;
				continue;
			}

			via_path  = strdup(param1);
			config_STRUPPER(via_path);

			if (parse_ax25addr(ax25viapath, via_path, 0x00)) {
				has_fault = 1;
				printf("%s:%d ERROR: via-path parameter is not valid AX.25 callsign: '%s'\n",
						cf->name, cf->linenum, via_path);
				free(via_path);
				via_path = NULL;
				continue;
			}

			if (debug)
				printf("via-path '%s'\n", via_path);

		} else if (strcmp(name, "msg-path") == 0) {

			// Validate that source callsign is "APRSIS"
			// or "DPRS" for this parameter

			if (source_aif == NULL ||
					(strcmp(source_aif->callsign,"APRSIS") != 0 &&
					 strcmp(source_aif->callsign,"DPRS") != 0)) {
				printf("%s:%d ERROR: msg-path parameter is available only on 'source APRSIS' and 'source DPRS' cases.\n",
						cf->name, cf->linenum);
				has_fault = 1;
				continue;
			}

			msg_path  = strdup(param1);
			config_STRUPPER(msg_path);

			if (parse_ax25addr(msgviapath, msg_path, 0x00)) {
				has_fault = 1;
				printf("%s:%d ERROR: msg-path parameter is not valid AX.25 callsign: '%s'\n",
						cf->name, cf->linenum, msg_path);
				free(msg_path);
				msg_path = NULL;
				continue;
			}

			if (debug)
				printf("msg-path '%s'\n", msg_path);
#endif
		} else if (strcmp(name,"<trace>") == 0) {
			if (source_trace == NULL) {
				source_trace = digipeater_config_tracewide(cf, 1);
				// prints errors internally
			} else {
				has_fault = 1;
				printf("%s:%d ERROR: double definition of <trace> block.\n",
						cf->name, cf->linenum);
			}

		} else if (strcmp(name,"<wide>") == 0) {
			if (source_wide == NULL) {
				source_wide  = digipeater_config_tracewide(cf, 0);
				// prints errors internally
			} else {
				has_fault = 1;
				printf("%s:%d ERROR: double definition of <wide> block.\n",
						cf->name, cf->linenum);
			}

		} else if (strcmp(name,"filter") == 0) {
			if (filter_parse(&filters, param1)) {
				// prints errors internally

				has_fault = 1;
				printf("%s:%d ERROR: Error at filter parser.\n",
						cf->name, cf->linenum);
			} else {
				if (debug)
					printf(" .. OK filter %s\n", param1);
			}

		} else if (strcmp(name,"relay-type") == 0 ||   // documented name
				strcmp(name,"relay-format") == 0 || // an alias
				strcmp(name,"digi-mode") == 0) {    // very old alias
			config_STRLOWER(param1);
			if (strcmp(param1,"digipeat") == 0) {
				relaytype = DIGIRELAY_DIGIPEAT;
			} else if (strcmp(param1,"digipeated") == 0) {
				relaytype = DIGIRELAY_DIGIPEAT;
			} else if (strcmp(param1,"digipeater") == 0) {
				relaytype = DIGIRELAY_DIGIPEAT;
			} else if (strcmp(param1,"directonly") == 0) {
				relaytype = DIGIRELAY_DIGIPEAT_DIRECTONLY;
			} else if (strcmp(param1,"third-party") == 0) {
				relaytype = DIGIRELAY_THIRDPARTY;
			} else if (strcmp(param1,"3rd-party") == 0) {
				relaytype = DIGIRELAY_THIRDPARTY;
			} else {
				printf("%s:%d ERROR: Digipeater <source>'s %s did not recognize: '%s' \n", cf->name, cf->linenum, name, param1);
				has_fault = 1;
			}
		} else {
			printf("%s:%d ERROR: Digipeater <source>'s %s did not recognize: '%s' \n", cf->name, cf->linenum, name, param1);
			has_fault = 1;
		}
	}

	if (source_aif == NULL) {
		has_fault = 1;
		printf("%s:%d ERROR: Missing or bad 'source =' definition at this <source> group.\n",
				cf->name, cf->linenum);
	}

	if (!has_fault && (source_aif != NULL)) {
		source = calloc(1,sizeof(*source));

		source->src_if        = source_aif;
		source->src_relaytype = relaytype;
		source->src_filters   = filters;
		source->src_trace     = source_trace;
		source->src_wide      = source_wide;
#ifndef DISABLE_IGATE
		source->via_path      = via_path;
		source->msg_path      = msg_path;
		memcpy(source->ax25viapath, ax25viapath, sizeof(ax25viapath));
		memcpy(source->msgviapath,  msgviapath,  sizeof(msgviapath));
		if (msg_path == NULL) { // default value of via-path !
			source->msg_path    = via_path;
			memcpy(source->msgviapath,  ax25viapath,  sizeof(ax25viapath));
		}
#endif

		source->viscous_delay = viscous_delay;

		source->tbf_limit     = (ratelimit * TOKENBUCKET_INTERVAL)/60;
		source->tbf_increment = (rateincrement * TOKENBUCKET_INTERVAL)/60;
		source->tokenbucket   = source->tbf_limit;

		// RE pattern reject filters
		source->sourceregscount      = regexsrc.sourceregscount;
		source->sourceregs           = regexsrc.sourceregs;
		source->destinationregscount = regexsrc.destinationregscount;
		source->destinationregs      = regexsrc.destinationregs;
		source->viaregscount         = regexsrc.viaregscount;
		source->viaregs              = regexsrc.viaregs;
		source->dataregscount        = regexsrc.dataregscount;
		source->dataregs             = regexsrc.dataregs;

	} else {
		// Errors detected
		free_tracewide(source_trace);
		free_tracewide(source_wide);
		// filters_free(filters);
		// free regexsrc's allocations
		if (debug)
			printf("Seen errors at <digipeater><source> definition.\n");
	}

	if (debug>1)printf(" .. <source> definition returning %p\n",source);
	return source;
}

int digipeater_config(struct configfile *cf)
{
	char *name, *param1;
	char *str = cf->buf;
	int has_fault = 0;
	int i;
	const int line0 = cf->linenum;

	struct aprx_interface *aif = NULL;
	float ratelimit = 60;
	float rateincrement = 60;
	float srcratelimit = 60;
	float srcrateincrement = 60;
	int sourcecount = 0;
	int dupestoretime = 30; // FIXME: parametrize! 30 is minimum..
	struct digipeater_source **sources = NULL;
	struct digipeater *digi = NULL;
	struct tracewide *traceparam = NULL;
	struct tracewide *wideparam  = NULL;

	while (readconfigline(cf) != NULL) {
		if (configline_is_comment(cf))
			continue;       /* Comment line, or empty line */

		// It can be severely indented...
		str = config_SKIPSPACE(cf->buf);

		name = str;
		str = config_SKIPTEXT(str, NULL);
		str = config_SKIPSPACE(str);
		config_STRLOWER(name);

		param1 = str;
		str = config_SKIPTEXT(str, NULL);
		str = config_SKIPSPACE(str);

		if (strcmp(name, "</digipeater>") == 0) {
			break;
		}
		if (strcmp(name, "transmit") == 0 ||
				strcmp(name, "transmitter") == 0) {
			if (strcasecmp(param1,"$mycall") == 0)
				param1 = (char*)mycall;

			aif = find_interface_by_callsign(param1);
			if (aif != NULL && (!aif->tx_ok)) {
				aif = NULL; // Not 
				printf("%s:%d ERROR: This transmit interface has no TX-OK TRUE setting: '%s'\n",
						cf->name, cf->linenum, param1);
				has_fault = 1;
			} else if (aif != NULL && aif->txrefcount > 0) {
				aif = NULL;
				printf("%s:%d ERROR: This transmit interface is being used on multiple <digipeater>s as transmitter: '%s'\n",
						cf->name, cf->linenum, param1);
				has_fault = 1;
			} else if (aif == NULL) {
				printf("%s:%d ERROR: Unknown interface: '%s'\n",
						cf->name, cf->linenum, param1);
				has_fault = 1;
			}

		} else if (strcmp(name, "ratelimit") == 0) {
			char *param2 = str;
			str = config_SKIPTEXT(str, NULL);
			str = config_SKIPSPACE(str);

			rateincrement = (float)atof(param1);
			ratelimit     = (float)atof(param2);
			if (rateincrement < 0.01 || rateincrement > rateincrementmax)
				rateincrement = 60;
			if (ratelimit < 0.01 || ratelimit > ratelimitmax)
				ratelimit = 60;
			if (ratelimit < rateincrement)
				rateincrement = ratelimit;
			if (debug)
				printf("  .. ratelimit %f %f\n",
						rateincrement, ratelimit);

		} else if (strcmp(name, "srcratelimit") == 0) {
			char *param2 = str;
			str = config_SKIPTEXT(str, NULL);
			str = config_SKIPSPACE(str);

			srcrateincrement = (float)atof(param1);
			srcratelimit     = (float)atof(param2);
			if (srcrateincrement < 0.01 || srcrateincrement > rateincrementmax)
				srcrateincrement = 60;
			if (srcratelimit < 0.01 || srcratelimit > ratelimitmax)
				srcratelimit = 60;
			if (srcratelimit < srcrateincrement)
				srcrateincrement = srcratelimit;
			if (debug)
				printf("  .. srcratelimit %f %f\n",
						srcrateincrement, srcratelimit);

		} else if (strcmp(name, "<trace>") == 0) {
			if (traceparam == NULL) {
				traceparam = digipeater_config_tracewide(cf, 1);
				if (traceparam == NULL) {
					printf("%s:%d ERROR: <trace> definition failed!\n",
							cf->name, cf->linenum);
					has_fault = 1;
				}
			} else {
				printf("%s:%d ERROR: Double definition of <trace> !\n",
						cf->name, cf->linenum);
				has_fault = 1;
			}

		} else if (strcmp(name, "<wide>") == 0) {
			if (wideparam == NULL) {
				wideparam = digipeater_config_tracewide(cf, 0);
				if (wideparam == NULL) {
					printf("%s:%d ERROR: <wide> definition failed!\n",
							cf->name, cf->linenum);
					has_fault = 1;
				}
			} else {
				printf("%s:%d ERROR: Double definition of <wide> !\n",
						cf->name, cf->linenum);
				has_fault = 1;
			}

		} else if (strcmp(name, "<source>") == 0) {
			struct digipeater_source *src =
				digipeater_config_source(cf);
			if (src != NULL) {
				// Found a source, link it!
				sources = realloc(sources, sizeof(void*) * (sourcecount+1));
				sources[sourcecount] = src;
				++sourcecount;
			} else {
				has_fault = 1;
				printf("%s:%d ERROR: <source> definition failed\n",
						cf->name, cf->linenum);
			}

		} else {
			printf("%s:%d ERROR: Unknown <digipeater> config keyword: '%s'\n",
					cf->name, cf->linenum, name);
			has_fault = 1;
			continue;
		}
	}

	if (aif == NULL && !has_fault) {
		printf("%s:%d ERROR: Digipeater defined without transmit interface.\n",
				cf->name, cf->linenum);
		has_fault = 1;
	}
	if (sourcecount == 0 && !has_fault) {
		printf("%s:%d ERROR: Digipeater defined without <source>:s.\n",
				cf->name, cf->linenum);
		has_fault = 1;
	}
	// Check that source definitions are unique
	for ( i = 0; i < sourcecount; ++i ) {
		int j;
		for (j = i+1; j < sourcecount; ++j) {
			if (sources[i]->src_if == sources[j]->src_if) {
				has_fault = 1;
				printf("%s:%d Two <source>s on this <digipeater> definition use same <interface>: '%s'\n",
						cf->name, line0, sources[i]->src_if->callsign);
			}
		}
	}

	if (has_fault) {
		// Free allocated resources and link pointers, if any
		for ( i = 0; i < sourcecount; ++i ) {
			free_source(sources[i]);
		}
		if (sources != NULL)
			free(sources);

		free_tracewide(traceparam);
		free_tracewide(wideparam);

		printf("ERROR: Config fault observed on <digipeater> definitions! \n");
	} else {
		// Construct the digipeater

		digi = calloc(1,sizeof(*digi));

		if (debug>1)printf("<digipeater> sourcecount=%d\n",sourcecount);

		// up-link all interfaces used as sources
		for ( i = 0; i < sourcecount; ++i ) {
			struct digipeater_source *src = sources[i];
			src->parent = digi; // Set parent link

			src->src_if->digisources = realloc( src->src_if->digisources,
					(src->src_if->digisourcecount +1) * (sizeof(void*)));
			src->src_if->digisources[src->src_if->digisourcecount] = src;
			src->src_if->digisourcecount += 1;
		}

		aif->txrefcount += 1; // Increment Tx usage Reference count.
		// We permit only one <digipeater> to
		// use any given Tx-interface. (Rx:es
		// permit multiple uses.)
		digi->transmitter   = aif;
		digi->tbf_limit     = (ratelimit * TOKENBUCKET_INTERVAL)/60;
		digi->tbf_increment = (rateincrement * TOKENBUCKET_INTERVAL)/60;
		digi->src_tbf_limit = (srcratelimit * TOKENBUCKET_INTERVAL)/60;
		digi->src_tbf_increment = (srcrateincrement * TOKENBUCKET_INTERVAL)/60;
		digi->tokenbucket   = digi->tbf_limit;

		digi->dupechecker   = dupecheck_new(dupestoretime);  // Dupecheck is per transmitter
#ifndef DISABLE_IGATE
		digi->historydb     = historydb_new();  // HistoryDB is per transmitter
#endif

		digi->trace         = (traceparam != NULL) ? traceparam : & default_trace_param;
		digi->wide          = (wideparam  != NULL) ? wideparam  : & default_wide_param;

		digi->sourcecount   = sourcecount;
		digi->sources       = sources;

		digis = realloc( digis, sizeof(void*) * (digi_count+1));
		digis[digi_count] = digi;
		++digi_count;
	}
	return has_fault;
}


static int decrement_ssid(uint8_t *ax25addr)
{
	// bit-field manipulation
	int ssid = (ax25addr[AX25ADDRLEN-1] >> 1) & 0x0F;
	if (ssid > 0)
		--ssid;
	ax25addr[AX25ADDRLEN-1] = (ax25addr[AX25ADDRLEN-1] & 0xE1) | (ssid << 1);
	return ssid;
}


/* 0 == accept, otherwise reject */
/*
   int digipeater_receive_filter(struct digipeater_source *src, struct pbuf_t *pb)
   {

   if (src->src_filters == NULL) {
   if (debug>1)
   printf("No source filters, accepted the packet from %s.\n", src->src_if->callsign);
   return 0;
   }
   int rc = filter_process(pb, src->src_filters, src->parent->historydb);
   if (rc != 1) {
   if (debug>1)
   printf("Source filtering rejected the packet from %s.\n", src->src_if->callsign);
   return 1;
   }
   if (debug>1)
   printf("Source filtering accepted the packet from %s.\n", src->src_if->callsign);
   return 0;
   }
   */

static void digipeater_receive_backend(struct digipeater_source *src, struct pbuf_t *pb)
{
	int len, viaindex;
	struct digistate state;
	struct viastate  viastate;
	struct digipeater *digi = src->parent;
	char viafield[14]; // room for text format
	uint8_t *axaddr, *e;

	memset(&state,    0, sizeof(state));
	memset(&viastate, 0, sizeof(viastate));

	//  2) Verify that none of our interface callsigns does match any
	//     of already DIGIPEATED via fields! (fields that have H-bit set)
	//   ( present implementation: this digi's transmitter callsign is
	//     verified)

	// Parse executed and requested WIDEn-N/TRACEn-N info
	if (parse_tnc2_hops(&state, src, pb)) {
		// A fault was observed! -- tests include "not this transmitter"
		if (debug>1)
			printf("Parse_tnc2_hops rejected this.");
		return;
	}

	if (pb->is_aprs) {

		if (state.v.probably_heard_direct) {
			// Collect a decaying average of distances to stations?
			//  .. could auto-beacon an aloha-circle - maybe
			//  .. note: this does not get packets that have no VIA fields.
			// Score of direct DX:es?
			//  .. note: this does not get packets that have no VIA fields.
		} else {
			if (src->src_relaytype == DIGIRELAY_DIGIPEAT_DIRECTONLY) {
				// Source relaytype is DIRECTONLY, and this was not
				// likely directly heard...
				if (debug>1) printf("DIRECTONLY -mode, and packet is probably not direct heard.");
				return;
			}
		}
		// Keep score of all DX packets?

		if (try_reject_filters(3, pb->info_start, src)) {
			if (debug>1)
				printf(" - Data body regexp filters reject\n");
			return; // data body regexp reject filters
		}

		// FIXME: 3) aprsc style filters checking in service area of the packet..

	}

	// 4) Hop-count filtering:

	// APRSIS sourced packets have different rules than DIGIPEAT
	// packets...
	if (state.v.hopsreq <= state.v.hopsdone) {
		if (debug>1) printf(" No remaining hops to execute.\n");
		return;
	}
	if (state.v.hopsreq   > digi->trace->maxreq  ||
			state.v.hopsreq   > digi->wide->maxreq   ||
			state.v.tracereq  > digi->trace->maxreq  ||
			state.v.digidone  > digi->trace->maxdone ||
			state.v.digidone  > digi->wide->maxdone  ||
			state.v.hopsdone  > digi->trace->maxdone ||
			state.v.hopsdone  > digi->wide->maxdone  ||
			state.v.tracedone > digi->trace->maxdone) {
		if (debug) printf(" Packet exceeds digipeat limits\n");
		if (!state.v.probably_heard_direct) {
			if (debug) printf(".. discard.\n");
			return;
		} else {
			state.v.fixall = 1;
		}
	}

	// if (debug) printf(" Packet accepted to digipeat!\n");

	state.ax25addrlen = pb->ax25addrlen;
	memcpy(state.ax25addr, pb->ax25addr, pb->ax25addrlen);
	axaddr = state.ax25addr + 2*AX25ADDRLEN;
	e      = state.ax25addr + state.ax25addrlen;

	if (state.v.fixall) {
		// Okay, insert my transmitter callsign on the first
		// VIA field, and mark the rest with H-bit
		// (in search loop below)
		int taillen = e - axaddr;
		if (state.ax25addrlen >= AX25ADDRMAXLEN) {
			if (debug) printf(" FIXALL TRACE overgrows the VIA fields! Dropping last of incoming ones.\n");
			// Drop the last via field to make room for insert below.
			state.ax25addrlen -= AX25ADDRLEN;
			taillen           -= AX25ADDRLEN;
		}
		// If we have a tail, move it up (there is always room for it)
		if (taillen > 0)
			memmove(axaddr+AX25ADDRLEN, axaddr, taillen);
		state.ax25addrlen += AX25ADDRLEN;
		e = state.ax25addr + state.ax25addrlen; // recalculate!

		// Put the transmitter callsign in
		memcpy(axaddr, digi->transmitter->ax25call, AX25ADDRLEN);

		// Set Address Termination bit at the last VIA field
		// (possibly ours, or maybe the previous one was truncated..)
		axaddr[state.ax25addrlen-1] |= AX25ATERM;
	}

	// Search for first AX.25 VIA field that does not have H-bit set:
	viaindex = 1; // First via field is number 2
	*viafield = 0; // clear that buffer for starters
	for (; axaddr < e; axaddr += AX25ADDRLEN, ++viaindex) {
		ax25_to_tnc2_fmtaddress(viafield, axaddr, 0);
		// if (debug>1) {
		//   printf(" via: %s", viafield);
		// }

		// Initial parsing said that things are seriously wrong..
		// .. and we will digipeat the packet with all H-bits set.
		if (state.v.fixall) axaddr[AX25ADDRLEN-1] |= AX25HBIT;

		if (!(axaddr[AX25ADDRLEN-1] & AX25HBIT)) // No "Has Been Digipeated" bit set
			break; // this doesn't happen in "fixall" mode
	}

	switch (src->src_relaytype) {
		case DIGIRELAY_THIRDPARTY:
			// Effectively disable the digipeat modifying of address
			axaddr = e;
			break;
		case DIGIRELAY_DIGIPEAT:
			// Normal functionality
			break;
		default: ;
	}

	// Unprocessed VIA field found (not in FIXALL mode)
	if (axaddr < e) {       // VIA-field of interest has been found

		// FIXME: 5) / 6) Cross-frequency/cross-band digipeat may add a special
		//                label telling that the message originated on other band

		// 7) WIDEn-N treatment (as well as transmitter matching digi)
		if (pb->digi_like_aprs) {
			if (strcmp(viafield,digi->transmitter->callsign) == 0 ||
					// Match on the transmitter callsign without the star...
					match_aliases(viafield, digi->transmitter)) {
				// .. or match transmitter interface alias.

				// Treat it as a TRACE request.

				int aterm = axaddr[AX25ADDRLEN-1] & AX25ATERM; // save old address termination bit
				// Put the transmitter callsign in, and set the H-bit.
				memcpy(axaddr, digi->transmitter->ax25call, AX25ADDRLEN);
				axaddr[AX25ADDRLEN-1] |= (AX25HBIT | aterm); // Set H-bit

			} else if ((len = match_tracewide(viafield, src->src_trace))) {
				count_single_tnc2_tracewide(&viastate, viafield, 1, len, viaindex);
			} else if ((len = match_tracewide(viafield, digi->trace))) {
				count_single_tnc2_tracewide(&viastate, viafield, 1, len, viaindex);
			} else if ((len = match_tracewide(viafield, src->src_wide))) {
				count_single_tnc2_tracewide(&viastate, viafield, 0, len, viaindex);
			} else if ((len = match_tracewide(viafield, digi->wide))) {
				count_single_tnc2_tracewide(&viastate, viafield, 0, len, viaindex);
			}

		} else { // Not "digi_as_aprs" rules

			if (strcmp(viafield,digi->transmitter->callsign) == 0) {
				// Match on the transmitter callsign without the star.
				// Treat it as a TRACE request.
				int aterm = axaddr[AX25ADDRLEN-1] & AX25ATERM; // save old address termination bit
				// Put the transmitter callsign in, and set the H-bit.
				memcpy(axaddr, digi->transmitter->ax25call, AX25ADDRLEN);
				axaddr[AX25ADDRLEN-1] |= (AX25HBIT | aterm); // Set H-bit

			} else if (match_aliases(viafield, digi->transmitter)) {
				// Match on the aliases.
				// Treat it as a TRACE request.
				int aterm = axaddr[AX25ADDRLEN-1] & AX25ATERM; // save old address termination bit
				// Put the transmitter callsign in, and set the H-bit.
				memcpy(axaddr, digi->transmitter->ax25call, AX25ADDRLEN);
				axaddr[AX25ADDRLEN-1] |= (AX25HBIT | aterm); // Set H-bit
			}
		}

		if (viastate.tracereq > viastate.tracedone) {
			// if (debug) printf(" TRACE on %s!\n",viafield);
			// Must move it up in memory to be able to put
			// transmitter callsign in
			int taillen = e - axaddr;
			int newssid;
			if (state.ax25addrlen >= AX25ADDRMAXLEN) {
				if (debug) printf(" TRACE overgrows the VIA fields! Discard.\n");
				return;
			}
			memmove(axaddr+AX25ADDRLEN, axaddr, taillen);
			state.ax25addrlen += AX25ADDRLEN;

			newssid = decrement_ssid(axaddr+AX25ADDRLEN);
			if (newssid <= 0)
				axaddr[2*AX25ADDRLEN-1] |= AX25HBIT; // Set H-bit
			// Put the transmitter callsign in, and set the H-bit.
			memcpy(axaddr, digi->transmitter->ax25call, AX25ADDRLEN);
			axaddr[AX25ADDRLEN-1] |= AX25HBIT; // Set H-bit

		} else if (viastate.hopsreq > viastate.hopsdone) {
			// If configuration didn't process "WIDE" et.al. as
			// a TRACE, then here we process them without trace..
			int newssid;
			if (debug) printf(" VIA on %s!\n",viafield);
			newssid = decrement_ssid(axaddr);
			if (newssid <= 0)
				axaddr[AX25ADDRLEN-1] |= AX25HBIT; // Set H-bit
		}
	}
	{
		history_cell_t *hcell;
		char tbuf[2800];
		int is_ui = 0, ui_pid = -1, frameaddrlen = 0, tnc2addrlen = 0, t2l;
		// uint8_t *u = state.ax25addr + state.ax25addrlen;
		// *u++ = 0;
		// *u++ = 0;
		// *u++ = 0;
		t2l = ax25_format_to_tnc( state.ax25addr,
				state.ax25addrlen+AX25ADDRLEN-1,
				tbuf, sizeof(tbuf),
				& frameaddrlen, &tnc2addrlen,
				& is_ui, &ui_pid );
		tbuf[t2l] = 0;
		if (debug) {
			printf(" out-hdr: '%s' data='",tbuf);
			(void)fwrite(pb->ax25data+2, pb->ax25datalen-2,  // without Control+PID
					1, stdout);
			printf("'\n");
		}

#ifndef DISABLE_IGATE
		// Insert into history database - track every packet
		hcell = historydb_insert_( digi->historydb, pb, 1 );

		if (hcell != NULL) {
			if (hcell->tokenbucket < 1.0) {
				if (debug) printf("TRANSMITTER SOURCE CALLSIGN RATELIMIT DISCARD.\n");
				return;
			}
			hcell->tokenbucket -= 1.0;
		}
#endif

		// Now we do token bucket filtering -- rate limiting
		if (digi->tokenbucket < 1.0) {
			if (debug) printf("TRANSMITTER RATELIMIT DISCARD.\n");
			return;
		}
		digi->tokenbucket -= 1.0;

		if (pb->is_aprs && rflogfile) {
			int t2l2;
			// Essentially Debug logging.. to file

			if (sizeof(tbuf) - pb->ax25datalen > t2l && t2l > 0) {
				// Have space for body too, skip leading Ctrl+PID bytes
				memcpy(tbuf+t2l, pb->ax25data+2, pb->ax25datalen-2); // Ctrl+PID skiped
				t2l2 = t2l + pb->ax25datalen-2; // tbuf size sans Ctrl+PID

				rflog( digi->transmitter->callsign, 'T', 0, tbuf, t2l2 );
				tbuf[t2l]=0;
			}
		}

		// Feed to dupe-filter (transmitter specific)
		// this means we have already seen it, and when 
		// it comes back from somewhere, we do not digipeat
		// it ourselves.

		// This recording is needed at output side of digipeater
		// for APRSIS and DPRS transmit gates.

		if (t2l>0) {
			dupecheck_aprs( digi->dupechecker,
					(const char *)tbuf,
					t2l,
					(const char *)pb->ax25data+2,
					pb->ax25datalen-2 );  // ignore Ctrl+PID
		} else {
			dupecheck_aprs( digi->dupechecker,
					(const char *)state.ax25addr,
					state.ax25addrlen,
					(const char *)pb->ax25data+2,
					pb->ax25datalen-2 );  // ignore Ctrl+PID
		}
	}

	// Feed to interface_transmit_ax25() with new header and body
	interface_transmit_ax25( digi->transmitter,
			state.ax25addr, state.ax25addrlen,
			(const char*)pb->ax25data, pb->ax25datalen );
	if (debug>1) printf("Done.\n");
}


void digipeater_receive( struct digipeater_source *src,
		struct pbuf_t *pb )
{
	// Below numbers like "4)" refer to Requirement Specification
	// paper chapter 2.6: Digipeater Rules

	//  The dupe-filter exists for APRS frames, possibly for some
	// selected UI frame types, and definitely not for CONS frames.

	if (debug)
		printf("digipeater_receive() from %s, is_aprs=%d viscous_delay=%d\n",
				src->src_if->callsign, pb->is_aprs, src->viscous_delay);

	if (src->tokenbucket < 1.0) {
		if (debug) printf("SOURCE RATELIMIT DISCARD\n");
		return;
	}
	src->tokenbucket -= 1.0;


	if (pb->is_aprs) {

		const int source_is_transmitter = (src->src_if ==
				src->parent->transmitter);

		// 1) Feed to dupe-filter (transmitter specific)
		//    If the dupe detector on this packet has reached
		//    count > 1, drop it.

		int jittery = src->viscous_delay > 0 ? random() % 3 + src->viscous_delay : 0;
		dupe_record_t *dupe = dupecheck_pbuf( src->parent->dupechecker,
				pb, jittery);
		if (dupe == NULL) {  // Oops.. allocation error!
			if (debug)
				printf("digipeater_receive() - dupecheck_pbuf() allocation error, packet discarded\n");
			return;
		}

		// 1.1) optional viscous delay!

		if (src->viscous_delay == 0) { // No delay, direct cases

			// First packet on direct source arrives here
			// with  seen = 1

			// 1.x) Analyze dupe checking

			if (debug>1)
				printf("Seen this packet %d times (delayed=%d)\n",
						dupe->delayed_seen + dupe->seen,
						dupe->delayed_seen);

			if (dupe->seen > 1) {
				// N:th direct packet, duplicate.
				// Drop this direct packet.
				if (debug>1) printf(".. discarded\n");
				return;
			}

			if (dupe->seen == 1 && dupe->delayed_seen > 0 &&
					dupe->pbuf == NULL) {
				// First direct, but dupe record does not have
				// pbuf anymore indicating that a delayed 
				// handling did process it sometime in past.
				// Drop this direct packet.
				if (debug>1) printf(".. discarded\n");
				return;
			}

			if (dupe->seen == 1 && dupe->delayed_seen >= 0 &&
					dupe->pbuf != NULL) {

				// First direct, and pbuf exists in dupe record.
				// It was added first to viscous queue, and
				// a bit latter came this direct one.
				// Remove one from viscous queue, and proceed
				// with direct processing.

				if (debug>1) printf(" .. discard dupe record, process immediately");

				pbuf_put(dupe->pbuf);
				dupe->pbuf = NULL;
				dupe = NULL; // Do not do  dupecheck_put() here!
			}

		} else {  // src->viscous_delay > 0

			// First packet on viscous source arrives here
			// with   dupe->delayed_seen = 1

			// Has this been seen on direct channel?
			if (dupe->seen > 0) {
				// Already processed thru direct processing,
				// no point in adding this to viscous delay queue
				if (debug>1)
					printf("Seen this packet %d times. Discarding it.\n",
							dupe->delayed_seen + dupe->seen);
				return;
			}

			// Depending on source definition, the transmitter is
			// either non-viscous or viscous.  We care about it
			// only when the source is viscous:
			if (source_is_transmitter)
				dupe->seen_on_transmitter += 1;

			if (dupe->delayed_seen > 1) {
				// 2nd or more of same packet from delayed source
				if (debug>1)
					printf("Seen this packet %d times.\n",
							dupe->delayed_seen + dupe->seen);

				// If any of them is transmitter interface, then
				// drop the queued packet, and drop current one.
				if (dupe->seen_on_transmitter > 0) {

					// If pbuf is on delayed queue, drop it.
					if (dupe->pbuf != NULL) {
						pbuf_put(dupe->pbuf);
						dupe->pbuf = NULL;
						dupe = NULL; // Do not do  dupecheck_put() here!
					}

				}
				if (debug>1) printf(".. discarded\n");
				return;
			}

			// First time that we have seen this packet at all.
			// Put the pbuf_t on viscous delay queue.. (Put
			// this dupe_record_t there, and the pbuf_t pointer
			// is already in that dupe_record_t.)
			src->viscous_queue_size += 1;
			if (src->viscous_queue_size > src->viscous_queue_space) {
				src->viscous_queue_space += 16;
				src->viscous_queue = realloc( src->viscous_queue,
						sizeof(void*) *
						src->viscous_queue_space );
			}
			src->viscous_queue[ src->viscous_queue_size -1 ]
				= dupecheck_get(dupe);

			if (debug) printf("%ld ENTER VISCOUS QUEUE: len=%d pbuf=%p\n",
					tick.tv_sec, src->viscous_queue_size, pb);
			return; // Put on viscous queue

		} 
	}
	// Send directly to backend
	if (debug>1) printf(".. direct to processing\n");
	digipeater_receive_backend(src, pb);
}

dupecheck_t *digipeater_find_dupecheck(const struct aprx_interface *aif)
{
	int i;
	for (i = 0; i < digi_count; ++i) {
		if (aif == digis[i]->transmitter)
			return digis[i]->dupechecker;
	}
	return NULL;
}

struct digipeater* digipeater_find_by_iface(const struct aprx_interface *aif) {
	int i;
	for (i = 0; i < digi_count; i++) {
		if (aif == digis[i]->transmitter)
			return digis[i];
	}

	if (debug > 1) printf(" Failed to find digipeater by aprx_interface\n");
	return NULL;
}


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


// Viscous queue processing needs poll digis <source>s for delayed actions
int  digipeater_prepoll(struct aprxpolls *app)
{
	int d, s;

	if (tokenbucket_timer.tv_sec == 0) {
		tokenbucket_timer = tick; // init this..
	}

	// If the time(2) has jumped around a lot,
	// and we didn't get around to do our work, reset the timer.

	if (time_reset) {
		digipeater_resettime(&tokenbucket_timer);
	}

	if (tv_timercmp( &tokenbucket_timer, &tick ) <= 0) {
		// Run the digipeater timer handling now
		// Will also advance the timer!
		if (debug>2) printf("digipeater_prepoll() run tokenbucket_timers\n");
		tv_timeradd_seconds( &tokenbucket_timer, &tokenbucket_timer, TOKENBUCKET_INTERVAL);
		run_tokenbucket_timers();
	}

	if (tv_timercmp( &tokenbucket_timer, &app->next_timeout ) <= 0) {
		app->next_timeout = tokenbucket_timer;
	}

	// if (debug>2) printf("digipeater_prepoll - 1 - timeout millis=%d\n",aprxpolls_millis(app));

	// Over all digipeaters..
	for (d = 0; d < digi_count; ++d) {
		struct digipeater *digi = digis[d];
		// Over all sources in those digipeaters
		for (s = 0; s < digi->sourcecount; ++s) {
			struct timeval tv;
			struct digipeater_source * src = digi->sources[s];
			// If viscous delay is zero, there is no work...
			// if (src->viscous_delay == 0)
			//   continue;
			// Delay is non-zero, perhaps there is work?
			if (src->viscous_queue_size == 0) // Empty queue
				continue;
			// First entry expires first
			tv.tv_sec = src->viscous_queue[0]->t + src->viscous_delay;
			tv.tv_usec = 0;
			if (tv_timercmp(&app->next_timeout, &tv) > 0) {
				app->next_timeout = tv;
				// if (debug>2) printf("digipeater_prepoll - 2 - timeout millis=%d\n",aprxpolls_millis(app));
			}
		}
	}

	return 0;
}

static void sourcecalltick(struct digipeater *digi);

int  digipeater_postpoll(struct aprxpolls *app)
{
	int d, s, i, donecount;

	if (tv_timercmp(&tokenbucket_timer, &tick) < 0) {
		tv_timeradd_seconds( &tokenbucket_timer, &tokenbucket_timer, TOKENBUCKET_INTERVAL);
		run_tokenbucket_timers();
	}

	// Over all digipeaters..
	for (d = 0; d < digi_count; ++d) {
		struct digipeater *digi = digis[d];

		// Over all sources in those digipeaters
		for (s = 0; s < digi->sourcecount; ++s) {
			struct digipeater_source * src = digi->sources[s];

			// If viscous delay is zero, there is no work...
			// if (src->viscous_delay == 0)
			//   continue;
			// Delay is non-zero, perhaps there is work?
			if (src->viscous_queue_size == 0) // Empty queue
				continue;
			// Feed backend from viscous queue
			donecount = 0;
			for (i = 0; i < src->viscous_queue_size; ++i) {
				struct dupe_record_t *dupe = src->viscous_queue[i];
				time_t t = dupe->t + src->viscous_delay;
				if ((t - tick.tv_sec) <= 0) {
					if (debug)printf("%ld LEAVE VISCOUS QUEUE: dupe=%p pbuf=%p\n",
							tick.tv_sec, dupe, dupe->pbuf);
					if (dupe->pbuf != NULL) {
						// We send the pbuf from viscous queue, if it still is
						// present in the dupe record.  (For example direct sourced
						// packets remove a packet from queued dupe record.)
						digipeater_receive_backend(src, dupe->pbuf);

						// Remove the delayed pbuf from this dupe record.
						pbuf_put(dupe->pbuf);
						dupe->pbuf = NULL;
					}
					dupecheck_put(dupe);
					++donecount;
				} else {
					break; // found a case we are not yet interested in.
				}
			}
			if (donecount > 0) {
				if (donecount >= src->viscous_queue_size) {
					// All cleared
					src->viscous_queue_size = 0;
				} else {
					// Compact the queue left after this processing round
					i = src->viscous_queue_size - donecount;
					memcpy(&src->viscous_queue[0],
							&src->viscous_queue[donecount],
							sizeof(void*) * i);
					src->viscous_queue_size = i;
				}
			}
		}
	}

	return 0;
}

static int  run_tokenbucket_timers()
{
	int d, s;
	// Over all digipeaters..
	for (d = 0; d < digi_count; ++d) {
		struct digipeater *digi = digis[d];

		digi->tokenbucket += digi->tbf_increment;
		if (digi->tokenbucket > digi->tbf_limit)
			digi->tokenbucket = digi->tbf_limit;

#ifndef DISABLE_IGATE
		sourcecalltick(digi);
#endif

		// Over all sources in those digipeaters
		for (s = 0; s < digi->sourcecount; ++s) {
			struct digipeater_source * src = digi->sources[s];

			src->tokenbucket += src->tbf_increment;
			if (src->tokenbucket > src->tbf_limit)
				src->tokenbucket = src->tbf_limit;

		}
	}

	return 0;
}

#ifndef DISABLE_IGATE
static void sourcecalltick(struct digipeater *digi)
{
	int i;
	historydb_t *db = digi->historydb;
	if (db == NULL) return; // Should never happen..

	for (i = 0; i < HISTORYDB_HASH_MODULO; ++i) {
		history_cell_t *c = db->hash[i];
		for ( ; c != NULL; c = c->next ) {
			c->tokenbucket += digi->src_tbf_increment;
			if (c->tokenbucket > digi->src_tbf_limit)
				c->tokenbucket = digi->src_tbf_limit;
		}
	}
}
#endif

// An utility function that exists at GNU Libc..

#if !defined(HAVE_MEMRCHR) && !defined(_FOR_VALGRIND_)
void   *memrchr(const void *s, int c, size_t n) {
	const unsigned char *p = s;
	c &= 0xFF;
	for (p = s+n; n > 0; --n, --p) {
		if (*p == c) return (void*)p;
	}
	return NULL;
}
#endif