C-Netz: Add tiny database to track if phones are online

Reject calls, if not online.

Use an interval to check if the phones are still online.

src/cnetz/Makefile.am

@@ -5,6 +5,7 @@ bin_PROGRAMS = \
 
 cnetz_SOURCES = \
 	cnetz.c \
+	database.c \
 	sysinfo.c \
 	telegramm.c \
 	dsp.c \

src/cnetz/cnetz.c

@@ -28,6 +28,7 @@
 #include "../common/call.h"
 #include "../common/cause.h"
 #include "cnetz.h"
+#include "database.h"
 #include "sysinfo.h"
 #include "telegramm.h"
 #include "dsp.h"
@@ -367,7 +368,13 @@ inval:
 	futln_fuvst = dialing[1] - '0';
 	futln_rest = atoi(dialing + 2);
 
-	/* 2. check if given number is already in a call, return BUSY */
+	/* 2. check if the subscriber is attached */
+	if (!find_db(futln_nat, futln_fuvst, futln_rest)) {
+		PDEBUG(DCNETZ, DEBUG_NOTICE, "Outgoing call to not attached subscriber, rejecting!\n");
+		return -CAUSE_OUTOFORDER;
+	}
+
+	/* 3. check if given number is already in a call, return BUSY */
 	for (sender = sender_head; sender; sender = sender->next) {
 		cnetz = (cnetz_t *) sender;
 		/* search transaction for this number */
@@ -386,12 +393,13 @@ inval:
 		return -CAUSE_BUSY;
 	}
 
-	/* 3. check if all senders are busy, return NOCHANNEL */
+	/* 4. check if all senders are busy, return NOCHANNEL */
 	if (!search_free_spk()) {
 		PDEBUG(DCNETZ, DEBUG_NOTICE, "Outgoing call, but no free channel, rejecting!\n");
 		return -CAUSE_NOCHANNEL;
 	}
 
+	/* 5. check if we have no OgK, return NOCHANNEL */
 	cnetz = search_ogk();
 	if (!cnetz) {
 		PDEBUG(DCNETZ, DEBUG_NOTICE, "Outgoing call, but OgK is currently busy, rejecting!\n");
@@ -400,7 +408,7 @@ inval:
 
 	PDEBUG(DCNETZ, DEBUG_INFO, "Call to mobile station, paging station id '%s'\n", dialing);
 
-	/* 4. trying to page mobile station */
+	/* 6. trying to page mobile station */
 	cnetz->sender.callref = callref;
 
 	trans = create_transaction(cnetz, TRANS_VAK, dialing[0] - '0', dialing[1] - '0', atoi(dialing + 2));
@@ -514,6 +522,25 @@ void call_out_release(int callref, int cause)
 	}
 }
 
+int cnetz_meldeaufruf(uint8_t futln_nat, uint8_t futln_fuvst, uint16_t futln_rest)
+{
+	cnetz_t *cnetz;
+	transaction_t *trans;
+
+	cnetz = search_ogk();
+	if (!cnetz) {
+		PDEBUG(DCNETZ, DEBUG_NOTICE, "'Meldeaufruf', but OgK is currently busy, rejecting!\n");
+		return -CAUSE_NOCHANNEL;
+	}
+	trans = create_transaction(cnetz, TRANS_MA, futln_nat, futln_fuvst, futln_rest);
+	if (!trans) {
+		PDEBUG(DCNETZ, DEBUG_ERROR, "Failed to create transaction\n");
+		return -CAUSE_TEMPFAIL;
+	}
+
+	return 0;
+}
+
 /*
  * Transaction handling
  */
@@ -575,6 +602,9 @@ static transaction_t *create_transaction(cnetz_t *cnetz, uint32_t state, uint8_t
 
 	link_transaction(trans, cnetz);
 
+	/* update database: now busy */
+	update_db(cnetz, futln_nat, futln_fuvst, futln_rest, 1, 0);
+
 	return trans;
 }
 
@@ -598,6 +628,9 @@ static void unlink_transaction(transaction_t *trans)
 /* destroy transaction */
 static void destroy_transaction(transaction_t *trans)
 {
+	/* update database: now idle */
+	update_db(trans->cnetz, trans->futln_nat, trans->futln_fuvst, trans->futln_rest, 0, trans->ma_failed);
+
 	unlink_transaction(trans);
 	
 	const char *rufnummer = transaction2rufnummer(trans);
@@ -626,6 +659,24 @@ static transaction_t *search_transaction(cnetz_t *cnetz, uint32_t state_mask)
 	return NULL;
 }
 
+static transaction_t *search_transaction_number(cnetz_t *cnetz, uint8_t futln_nat, uint8_t futln_fuvst, uint16_t futln_rest)
+{
+	transaction_t *trans = cnetz->trans_list;
+
+	while (trans) {
+		if (trans->futln_nat == futln_nat
+		 && trans->futln_fuvst == futln_fuvst
+		 && trans->futln_rest == futln_rest) {
+			const char *rufnummer = transaction2rufnummer(trans);
+			PDEBUG(DCNETZ, DEBUG_DEBUG, "Found transaction for subscriber '%s'\n", rufnummer);
+			return trans;
+		}
+		trans = trans->next;
+	}
+
+	return NULL;
+}
+
 static const char *trans_state_name(int state)
 {
 	switch (state) {
@@ -637,6 +688,8 @@ static const char *trans_state_name(int state)
 		return "UM";
 	case TRANS_MA:
 		return "MA";
+	case TRANS_MFT:
+		return "MFT";
 	case TRANS_VWG:
 		return "VWG";
 	case TRANS_WAF:
@@ -743,6 +796,8 @@ static void transaction_timeout(struct timer *timer)
 	case TRANS_WAF:
 		PDEBUG(DCNETZ, DEBUG_NOTICE, "No response after dialing request 'Wahlaufforderung'\n");
 		if (++trans->count == 3) {
+			/* no response to dialing is like MA failed */
+			trans->ma_failed = 1;
 			trans_new_state(trans, TRANS_WBN);
 			break;
 		}
@@ -785,6 +840,10 @@ static void transaction_timeout(struct timer *timer)
 		cnetz->sender.callref = 0;
 		cnetz_release(trans, CNETZ_CAUSE_FUNKTECHNISCH);
 		break;
+	case TRANS_MFT:
+		trans->ma_failed = 1;
+		destroy_transaction(trans);
+		break;
 	default:
 		PDEBUG(DCNETZ, DEBUG_ERROR, "Timeout unhandled in state %d\n", trans->state);
 	}
@@ -963,7 +1022,7 @@ const telegramm_t *cnetz_transmit_telegramm_meldeblock(cnetz_t *cnetz)
 	telegramm.ogk_vorschlag = CNETZ_OGK_KANAL;
 	telegramm.fuz_rest_nr = si.fuz_rest;
 
-	trans = search_transaction(cnetz, TRANS_VWG);
+	trans = search_transaction(cnetz, TRANS_VWG | TRANS_MA);
 	if (trans) {
 		switch (trans->state) {
 		case TRANS_VWG:
@@ -975,6 +1034,15 @@ const telegramm_t *cnetz_transmit_telegramm_meldeblock(cnetz_t *cnetz)
 			trans_new_state(trans, TRANS_WAF);
 			timer_start(&trans->timer, 4.0); /* Wait two slot cycles until resending */
 			break;
+		case TRANS_MA:
+			PDEBUG(DCNETZ, DEBUG_INFO, "Sending keepalive request 'Meldeaufruf'\n");
+			telegramm.opcode = OPCODE_MA_M;
+			telegramm.futln_nationalitaet = trans->futln_nat;
+			telegramm.futln_heimat_fuvst_nr = trans->futln_fuvst;
+			telegramm.futln_rest_nr = trans->futln_rest;
+			trans_new_state(trans, TRANS_MFT);
+			timer_start(&trans->timer, 4.0); /* Wait two slot cycles until timeout */
+			break;
 		default:
 			; /* MLR */
 		}
@@ -1066,6 +1134,15 @@ void cnetz_receive_telegramm_ogk(cnetz_t *cnetz, telegramm_t *telegramm, int blo
 		trans_new_state(trans, TRANS_WBP);
 		valid_frame = 1;
 		break;
+	case OPCODE_MFT_M:
+		trans = search_transaction_number(cnetz, telegramm->futln_nationalitaet, telegramm->futln_heimat_fuvst_nr, telegramm->futln_rest_nr);
+		if (!trans) {
+			PDEBUG(DCNETZ, DEBUG_NOTICE, "Received acknowledge 'Meldun Funktelefonteilnemer' message without transaction, ignoring!\n");
+			break;
+		}
+		destroy_transaction(trans);
+		valid_frame = 1;
+		break;
 	default:
 		PDEBUG(DCNETZ, DEBUG_NOTICE, "Received unexpected Telegramm (opcode %d = %s)\n", opcode, telegramm_name(opcode));
 	}

src/cnetz/cnetz.h

@@ -32,24 +32,25 @@ enum cnetz_state {
 	/* roaming to different base station/network */
 #define	TRANS_UM	(1 << 1)	/* roaming request received, sending reply */
 	/* check if phone is still on */
-#define	TRANS_MA	(1 << 2)	/* periodic online check sent, waiting for reply */
+#define	TRANS_MA	(1 << 2)	/* periodic online check, waiting for time slot to send order */
+#define	TRANS_MFT	(1 << 3)	/* periodic online check sent, waiting for reply */
 	/* mobile originated call */
-#define	TRANS_VWG	(1 << 3)	/* received dialing request, waiting for time slot to send dial order */
+#define	TRANS_VWG	(1 << 4)	/* received dialing request, waiting for time slot to send dial order */
-#define	TRANS_WAF	(1 << 4)	/* dial order sent, waiting for dialing */
+#define	TRANS_WAF	(1 << 5)	/* dial order sent, waiting for dialing */
-#define	TRANS_WBP	(1 << 5)	/* dialing received, waiting for time slot to acknowledge call */
+#define	TRANS_WBP	(1 << 6)	/* dialing received, waiting for time slot to acknowledge call */
-#define	TRANS_WBN	(1 << 6)	/* dialing received, waiting for time slot to reject call */
+#define	TRANS_WBN	(1 << 7)	/* dialing received, waiting for time slot to reject call */
-#define	TRANS_VAG	(1 << 7)	/* establishment of call sent, switching channel */
+#define	TRANS_VAG	(1 << 8)	/* establishment of call sent, switching channel */
 	/* mobile terminated call */
-#define	TRANS_VAK	(1 << 8)	/* establishment of call sent, switching channel */
+#define	TRANS_VAK	(1 << 9)	/* establishment of call sent, switching channel */
 	/* traffic channel */
-#define	TRANS_BQ	(1 << 9)	/* accnowledge channel */
+#define	TRANS_BQ	(1 << 10)	/* accnowledge channel */
-#define	TRANS_VHQ	(1 << 10)	/* hold call */
+#define	TRANS_VHQ	(1 << 11)	/* hold call */
-#define	TRANS_RTA	(1 << 11)	/* hold call and make the phone ring */
+#define	TRANS_RTA	(1 << 12)	/* hold call and make the phone ring */
-#define	TRANS_DS	(1 << 12)	/* establish speech connection */
+#define	TRANS_DS	(1 << 13)	/* establish speech connection */
-#define	TRANS_AHQ	(1 << 13)	/* establish speech connection after answer */
+#define	TRANS_AHQ	(1 << 14)	/* establish speech connection after answer */
 	/* release */
-#define	TRANS_AF	(1 << 14)	/* release connection by base station */
+#define	TRANS_AF	(1 << 15)	/* release connection by base station */
-#define	TRANS_AT	(1 << 15)	/* release connection by mobile station */
+#define	TRANS_AT	(1 << 16)	/* release connection by mobile station */
 
 /* timers */
 #define F_BQ		8		/* number of not received frames at BQ state */
@@ -81,6 +82,7 @@ typedef struct transaction {
 	struct timer		timer;			/* for varous timeouts */
 	int			mo_call;		/* flags a moile originating call */
 	int			mt_call;		/* flags a moile terminating call */
+	int			ma_failed;		/* failed to get a response from MS */
 } transaction_t;
 
 struct clock_speed {
@@ -157,6 +159,7 @@ int cnetz_init(void);
 int cnetz_create(int kanal, enum cnetz_chan_type chan_type, const char *sounddev, int samplerate, int cross_channels, double rx_gain, int auth, int ms_power, int measure_speed, double clock_speed[2], double deviation, double noise, int pre_emphasis, int de_emphasis, const char *write_wave, const char *read_wave, int loopback);
 void cnetz_destroy(sender_t *sender);
 void cnetz_sync_frame(cnetz_t *cnetz, double sync, int ts);
+int cnetz_meldeaufruf(uint8_t futln_nat, uint8_t futln_fuvst, uint16_t futln_rest);
 const struct telegramm *cnetz_transmit_telegramm_rufblock(cnetz_t *cnetz);
 const struct telegramm *cnetz_transmit_telegramm_meldeblock(cnetz_t *cnetz);
 void cnetz_receive_telegramm_ogk(cnetz_t *cnetz, struct telegramm *telegramm, int block);

src/cnetz/database.c

@@ -0,0 +1,156 @@
+/* C-Netz database
+ *
+ * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
+ * All Rights Reserved
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include "../common/debug.h"
+#include "../common/timer.h"
+#include "cnetz.h"
+#include "database.h"
+
+#define MELDE_INTERVAL		60.0
+#define MELDE_WIEDERHOLUNG	10.0
+#define MELDE_MAXIMAL		3
+
+typedef struct cnetz_database {
+	struct cnetz_database	*next;
+	uint8_t			futln_nat;	/* who ... */
+	uint8_t			futln_fuvst;
+	uint16_t		futln_rest;
+	struct timer		timer;		/* timer for next availability check */
+	int			retry;		/* counts number of retries */
+} cnetz_db_t;
+
+cnetz_db_t *cnetz_db_head;
+
+/* destroy transaction */
+static void remove_db(cnetz_db_t *db)
+{
+	cnetz_db_t **dbp;
+
+	/* uinlink */
+	dbp = &cnetz_db_head;
+	while (*dbp && *dbp != db)
+		dbp = &((*dbp)->next);
+	if (!(*dbp)) {
+		PDEBUG(DDB, DEBUG_ERROR, "Transaction not in list, please fix!!\n");
+		abort();
+	}
+	*dbp = db->next;
+
+	PDEBUG(DDB, DEBUG_INFO, "Removing subscriber '%d,%d,%d' from database.\n", db->futln_nat, db->futln_fuvst, db->futln_rest);
+
+	timer_exit(&db->timer);
+
+	free(db);
+}
+
+/* Timeout handling */
+static void db_timeout(struct timer *timer)
+{
+	cnetz_db_t *db = (cnetz_db_t *)timer->priv;
+	int rc;
+
+	PDEBUG(DDB, DEBUG_INFO, "Check, if subscriber '%d,%d,%d' is still available.\n", db->futln_nat, db->futln_fuvst, db->futln_rest);
+	
+	rc = cnetz_meldeaufruf(db->futln_nat, db->futln_fuvst, db->futln_rest);
+	if (rc < 0) {
+		/* OgK is used for speech, but this never happens in a real
+		 * network. We just assume that the phone has responded and
+		 * assume we had a response. */
+		PDEBUG(DDB, DEBUG_INFO, "OgK busy, so we assume a positive response.\n");
+		timer_start(&db->timer, MELDE_INTERVAL); /* when to check avaiability again */
+		db->retry = 0;
+	}
+}
+
+/* create/update db entry */
+void update_db(cnetz_t *cnetz, uint8_t futln_nat, uint8_t futln_fuvst, uint16_t futln_rest, int busy, int failed)
+{
+	cnetz_db_t *db, **dbp;
+
+	/* search transaction for this subsriber */
+	db = cnetz_db_head;
+	while (db) {
+		if (db->futln_nat == futln_nat
+		 && db->futln_fuvst == futln_fuvst
+		 && db->futln_rest == futln_rest)
+			break;
+		db = db->next;
+	}
+	if (!db) {
+		db = calloc(1, sizeof(*db));
+		if (!db) {
+			PDEBUG(DDB, DEBUG_ERROR, "No memory!\n");
+			return;
+		}
+		timer_init(&db->timer, db_timeout, db);
+
+		db->futln_nat = futln_nat;
+		db->futln_fuvst = futln_fuvst;
+		db->futln_rest = futln_rest;
+
+		/* attach to end of list */
+		dbp = &cnetz_db_head;
+		while (*dbp)
+			dbp = &((*dbp)->next);
+		*dbp = db;
+
+		PDEBUG(DDB, DEBUG_INFO, "Adding subscriber '%d,%d,%d' to database.\n", db->futln_nat, db->futln_fuvst, db->futln_rest);
+	}
+
+	if (busy) {
+		PDEBUG(DDB, DEBUG_INFO, "Subscriber '%d,%d,%d' busy now.\n", db->futln_nat, db->futln_fuvst, db->futln_rest);
+		timer_stop(&db->timer);
+	} else if (!failed) {
+		PDEBUG(DDB, DEBUG_INFO, "Subscriber '%d,%d,%d' idle now.\n", db->futln_nat, db->futln_fuvst, db->futln_rest);
+		timer_start(&db->timer, MELDE_INTERVAL); /* when to check avaiability (again) */
+		db->retry = 0;
+	} else {
+		if (++db->retry == MELDE_MAXIMAL) {
+			PDEBUG(DDB, DEBUG_NOTICE, "Paging subscriber '%d,%d,%d' failed.\n", db->futln_nat, db->futln_fuvst, db->futln_rest);
+			remove_db(db);
+			return;
+		}
+		timer_start(&db->timer, MELDE_WIEDERHOLUNG); /* when to do retry */
+	}
+}
+
+int find_db(uint8_t futln_nat, uint8_t futln_fuvst, uint16_t futln_rest)
+{
+	cnetz_db_t *db = cnetz_db_head;
+
+	while (db) {
+		if (db->futln_nat == futln_nat
+		 && db->futln_fuvst == futln_fuvst
+		 && db->futln_rest == futln_rest)
+			return 1;
+		db = db->next;
+	}
+	return 0;
+}
+
+void flush_db(void)
+{
+	while (cnetz_db_head)
+		remove_db(cnetz_db_head);
+}
+

src/cnetz/database.h

@@ -0,0 +1,5 @@
+
+void update_db(cnetz_t *cnetz, uint8_t futln_nat, uint8_t futln_fuvst, uint16_t futln_rest, int busy, int failed);
+int find_db(uint8_t futln_nat, uint8_t futln_fuvst, uint16_t futln_rest);
+void flush_db(void);
+

src/cnetz/main.c

@@ -32,6 +32,7 @@
 #include "../common/freiton.h"
 #include "../common/besetztton.h"
 #include "cnetz.h"
+#include "database.h"
 #include "sysinfo.h"
 #include "dsp.h"
 #include "telegramm.h"
@@ -292,6 +293,8 @@ fail:
 	if (use_mncc_sock)
 		mncc_exit();
 
+	flush_db();
+
 	/* destroy transceiver instance */
 	while (sender_head)
 		cnetz_destroy(sender_head);

src/common/debug.c

@@ -43,6 +43,7 @@ struct debug_cat {
 	{ "frame", "\033[0;36m" },
 	{ "call", "\033[1;37m" },
 	{ "mncc", "\033[1;32m" },
+	{ "database", "\033[0;33m" },
 };
 
 int debuglevel = DEBUG_INFO;

src/common/debug.h

@@ -14,6 +14,7 @@
 #define DFRAME		7
 #define DCALL		8
 #define DMNCC		9
+#define DDB		10
 
 #define PDEBUG(cat, level, fmt, arg...) _printdebug(__FILE__, __FUNCTION__, __LINE__, cat, level, fmt, ## arg)
 void _printdebug(const char *file, const char *function, int line, int cat, int level, const char *fmt, ...);