An implementation of Analog cellular networks like A-Netz, B-Netz, C-Netz, NMT, AMPS, TACS, JTACS, Radiocom 2000, IMTS, MPT1327, Eurosignal and more http://osmocom-analog.eversberg.eu/
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osmocom-analog/src/anetz/anetz.c

458 lines
12 KiB

/* A-Netz protocol handling
*
* (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 <errno.h>
#include "../common/debug.h"
#include "../common/timer.h"
#include "../common/call.h"
#include "../common/cause.h"
#include "anetz.h"
#include "dsp.h"
/* Call reference for calls from mobile station to network
This offset of 0x400000000 is required for MNCC interface. */
static int new_callref = 0x40000000;
/* Timers */
#define PAGING_TO 30 /* Nach dieser Zeit ist der Operator genervt... */
/* Convert channel number to frequency number of base station.
Set 'unterband' to 1 to get frequency of mobile station. */
double anetz_kanal2freq(int kanal, int unterband)
{
double freq = 162.050;
freq += (kanal - 30) * 0.050;
if (kanal >= 45)
freq += 6.800;
if (unterband)
freq -= 4.500;
return freq;
}
/* Convert paging frequency number to to frequency. */
static double anetz_dauerruf_frq(int n)
{
if (n < 1 || n > 30)
abort();
return 337.5 + (double)n * 15.0;
}
/* Table with frequency sets to use for paging. */
static struct anetz_dekaden {
int dekade[4];
} anetz_gruppenkennziffer[10] = {
{ { 2, 2, 3, 3 } }, /* 0 */
{ { 1, 1, 2, 2 } }, /* 1 */
{ { 1, 1, 3, 3 } }, /* 2 */
{ { 1, 1, 2, 3 } }, /* 3 */
{ { 1, 2, 2, 3 } }, /* 4 */
{ { 1, 2, 3, 3 } }, /* 5 */
{ { 1, 1, 1, 2 } }, /* 6 */
{ { 1, 1, 1, 3 } }, /* 7 */
{ { 2, 2, 2, 3 } }, /* 8 */
{ { 1, 2, 2, 2 } }, /* 9 */
};
/* Takes the last 5 digits of a number and returns 4 paging tones.
If number is invalid, NULL is returned. */
static double *anetz_nummer2freq(const char *nummer)
{
int f[4];
static double freq[4];
int *dekade;
int i, j, digit;
/* get last 5 digits */
if (strlen(nummer) < 5) {
PDEBUG(DANETZ, DEBUG_ERROR, "Number must have at least 5 digits!\n");
return NULL;
}
nummer = nummer + strlen(nummer) - 5;
/* check for digits */
for (i = 0; i < 4; i++) {
if (nummer[i] < '0' || nummer[i] > '9') {
PDEBUG(DANETZ, DEBUG_ERROR, "Number must have digits 0..9!\n");
return NULL;
}
}
/* get decade */
dekade = anetz_gruppenkennziffer[*nummer - '0'].dekade;
PDEBUG(DANETZ, DEBUG_DEBUG, "Dekaden: %d %d %d %d\n", dekade[0], dekade[1], dekade[2], dekade[3]);
nummer++;
/* get 4 frequencies out of decades */
for (i = 0; i < 4; i++) {
digit = nummer[i] - '0';
if (digit == 0)
digit = 10;
f[i] = (dekade[i] - 1) * 10 + digit;
freq[i] = anetz_dauerruf_frq(f[i]);
for (j = 0; j < i; j++) {
if (dekade[i] == dekade[j] && nummer[i] == nummer[j]) {
PDEBUG(DANETZ, DEBUG_NOTICE, "Number invalid, digit #%d and #%d of '%s' use same frequency F%d=%.1f of same decade %d!\n", i+1, j+1, nummer, f[i], freq[i], dekade[i]);
return NULL;
}
}
}
PDEBUG(DANETZ, DEBUG_DEBUG, "Frequencies: F%d=%.1f F%d=%.1f F%d=%.1f F%d=%.1f\n", f[0], freq[0], f[1], freq[1], f[2], freq[2], f[3], freq[3]);
return freq;
}
/* global init */
int anetz_init(void)
{
return 0;
}
static void anetz_timeout(struct timer *timer);
/* Create transceiver instance and link to a list. */
int anetz_create(const char *sounddev, int samplerate, int kanal, int loopback, double loss_volume)
{
anetz_t *anetz;
int rc;
if (kanal < 30 || kanal > 63) {
PDEBUG(DANETZ, DEBUG_ERROR, "Channel ('Kanal') number %d invalid.\n", kanal);
return -EINVAL;
}
anetz = calloc(1, sizeof(anetz_t));
if (!anetz) {
PDEBUG(DANETZ, DEBUG_ERROR, "No memory!\n");
return -EIO;
}
PDEBUG(DANETZ, DEBUG_DEBUG, "Creating 'A-Netz' instance for 'Kanal' = %d (sample rate %d).\n", kanal, samplerate);
/* init general part of transceiver */
rc = sender_create(&anetz->sender, sounddev, samplerate, kanal, loopback, loss_volume, -1);
if (rc < 0) {
PDEBUG(DANETZ, DEBUG_ERROR, "Failed to init 'Sender' processing!\n");
goto error;
}
/* init audio processing */
rc = dsp_init_sender(anetz);
if (rc < 0) {
PDEBUG(DANETZ, DEBUG_ERROR, "Failed to init signal processing!\n");
goto error;
}
/* go into idle state */
PDEBUG(DANETZ, DEBUG_INFO, "Entering IDLE state, sending 2280 Hz tone.\n");
anetz->state = ANETZ_FREI;
anetz->dsp_mode = DSP_MODE_TONE;
timer_init(&anetz->timer, anetz_timeout, anetz);
return 0;
error:
anetz_destroy(&anetz->sender);
return rc;
}
/* Destroy transceiver instance and unlink from list. */
void anetz_destroy(sender_t *sender)
{
anetz_t *anetz = (anetz_t *) sender;
PDEBUG(DANETZ, DEBUG_DEBUG, "Destroying 'A-Netz' instance for 'Kanal' = %d.\n", sender->kanal);
timer_exit(&anetz->timer);
dsp_cleanup_sender(anetz);
sender_destroy(&anetz->sender);
free(sender);
}
/* Abort connection towards mobile station by sending idle tone. */
static void anetz_go_idle(anetz_t *anetz)
{
timer_stop(&anetz->timer);
PDEBUG(DANETZ, DEBUG_INFO, "Entering IDLE state, sending 2280 Hz tone.\n");
anetz->state = ANETZ_FREI;
anetz->dsp_mode = DSP_MODE_TONE;
anetz->station_id[0] = '\0';
}
/* Enter paging state and transmit 4 paging tones. */
static void anetz_page(anetz_t *anetz, const char *dial_string, double *freq)
{
PDEBUG(DANETZ, DEBUG_INFO, "Entering paging state, sending 'Selektivruf' to '%s'.\n", dial_string);
anetz->state = ANETZ_ANRUF;
anetz->dsp_mode = DSP_MODE_PAGING;
dsp_set_paging(anetz, freq);
strcpy(anetz->station_id, dial_string);
timer_start(&anetz->timer, PAGING_TO);
}
/* Loss of signal was detected, release active call. */
void anetz_loss_indication(anetz_t *anetz)
{
if (anetz->state == ANETZ_GESPRAECH) {
PDEBUG(DANETZ, DEBUG_NOTICE, "Detected loss of signal, releasing.\n");
anetz_go_idle(anetz);
call_in_release(anetz->sender.callref, CAUSE_TEMPFAIL);
anetz->sender.callref = 0;
}
}
/* A continuous tone was detected or is gone. */
void anetz_receive_tone(anetz_t *anetz, int tone)
{
if (tone >= 0)
PDEBUG(DANETZ, DEBUG_DEBUG, "Received contiuous %d Hz tone.\n", (tone) ? 1750 : 2280);
else
PDEBUG(DANETZ, DEBUG_DEBUG, "Continuous tone is gone.\n");
if (anetz->sender.loopback) {
return;
}
switch (anetz->state) {
case ANETZ_FREI:
/* initiate call on calling tone */
if (tone == 1) {
PDEBUG(DANETZ, DEBUG_INFO, "Received 1750 Hz calling signal from mobile station, removing idle signal.\n");
anetz->state = ANETZ_GESPRAECH;
anetz->dsp_mode = DSP_MODE_SILENCE;
break;
}
break;
case ANETZ_GESPRAECH:
/* throughconnect speech when calling/answer tone is gone */
if (tone != 1) {
if (!anetz->sender.callref) {
int callref = ++new_callref;
int rc;
PDEBUG(DANETZ, DEBUG_INFO, "1750 Hz signal from mobile station is gone, setup call.\n");
rc = call_in_setup(callref, anetz->station_id, "0");
if (rc < 0) {
PDEBUG(DANETZ, DEBUG_NOTICE, "Call rejected (cause %d), releasing.\n", -rc);
anetz_go_idle(anetz);
break;
}
anetz->sender.callref = callref;
} else {
PDEBUG(DANETZ, DEBUG_INFO, "1750 Hz signal from mobile station is gone, answer call.\n");
call_in_answer(anetz->sender.callref, anetz->station_id);
}
anetz->dsp_mode = DSP_MODE_AUDIO;
}
/* release call */
if (tone == 1) {
PDEBUG(DANETZ, DEBUG_INFO, "Received 1750 Hz release signal from mobile station, sending idle signal.\n");
anetz_go_idle(anetz);
call_in_release(anetz->sender.callref, CAUSE_NORMAL);
anetz->sender.callref = 0;
break;
}
break;
case ANETZ_ANRUF:
/* answer call on answer tone */
if (tone == 1) {
PDEBUG(DANETZ, DEBUG_INFO, "Received 1750 Hz answer signal from mobile station, removing paging tones.\n");
timer_stop(&anetz->timer);
anetz->state = ANETZ_GESPRAECH;
anetz->dsp_mode = DSP_MODE_SILENCE;
break;
}
default:
break;
}
}
/* Timeout handling */
static void anetz_timeout(struct timer *timer)
{
anetz_t *anetz = (anetz_t *)timer->priv;
switch (anetz->state) {
case ANETZ_ANRUF:
PDEBUG(DANETZ, DEBUG_NOTICE, "Timeout while waiting for answer, releasing.\n");
anetz_go_idle(anetz);
call_in_release(anetz->sender.callref, CAUSE_NOANSWER);
anetz->sender.callref = 0;
break;
default:
break;
}
}
/* Call control starts call towards mobile station. */
int call_out_setup(int callref, char *dialing)
{
sender_t *sender;
anetz_t *anetz;
double *freq;
/* 1. check if number is invalid, return INVALNUMBER */
if (strlen(dialing) > 7) {
inval:
PDEBUG(DANETZ, DEBUG_NOTICE, "Outgoing call to invalid number '%s', rejecting!\n", dialing);
return -CAUSE_INVALNUMBER;
}
freq = anetz_nummer2freq(dialing);
if (!freq)
goto inval;
/* 2. check if given number is already in a call, return BUSY */
for (sender = sender_head; sender; sender = sender->next) {
anetz = (anetz_t *) sender;
if (strlen(anetz->station_id) < 5)
continue;
if (!strcmp(anetz->station_id + strlen(anetz->station_id) - 5, dialing + strlen(dialing) - 5))
break;
}
if (sender) {
PDEBUG(DANETZ, DEBUG_NOTICE, "Outgoing call to busy number, rejecting!\n");
return -CAUSE_BUSY;
}
/* 3. check if all senders are busy, return NOCHANNEL */
for (sender = sender_head; sender; sender = sender->next) {
anetz = (anetz_t *) sender;
if (anetz->state == ANETZ_FREI)
break;
}
if (!sender) {
PDEBUG(DANETZ, DEBUG_NOTICE, "Outgoing call, but no free channel, rejecting!\n");
return -CAUSE_NOCHANNEL;
}
PDEBUG(DANETZ, DEBUG_INFO, "Call to mobile station, paging with tones: %.1f %.1f %.1f %.1f\n", freq[0], freq[1], freq[2], freq[3]);
/* 4. trying to page mobile station */
sender->callref = callref;
anetz_page(anetz, dialing, freq);
call_in_alerting(callref);
return 0;
}
/* Call control sends disconnect (with tones).
* An active call stays active, so tones and annoucements can be received
* by mobile station.
*/
void call_out_disconnect(int callref, int cause)
{
sender_t *sender;
anetz_t *anetz;
PDEBUG(DANETZ, DEBUG_INFO, "Call has been disconnected by network.\n");
for (sender = sender_head; sender; sender = sender->next) {
anetz = (anetz_t *) sender;
if (sender->callref == callref)
break;
}
if (!sender) {
PDEBUG(DANETZ, DEBUG_NOTICE, "Outgoing disconnect, but no callref!\n");
call_in_release(callref, CAUSE_INVALCALLREF);
return;
}
/* Release when not active */
if (anetz->state == ANETZ_GESPRAECH)
return;
switch (anetz->state) {
case ANETZ_ANRUF:
PDEBUG(DANETZ, DEBUG_NOTICE, "Outgoing disconnect, during alerting, going idle!\n");
anetz_go_idle(anetz);
break;
default:
break;
}
call_in_release(callref, cause);
sender->callref = 0;
}
/* Call control releases call toward mobile station. */
void call_out_release(int callref, int cause)
{
sender_t *sender;
anetz_t *anetz;
PDEBUG(DANETZ, DEBUG_INFO, "Call has been released by network, releasing call.\n");
for (sender = sender_head; sender; sender = sender->next) {
anetz = (anetz_t *) sender;
if (sender->callref == callref)
break;
}
if (!sender) {
PDEBUG(DANETZ, DEBUG_NOTICE, "Outgoing release, but no callref!\n");
/* don't send release, because caller already released */
return;
}
sender->callref = 0;
switch (anetz->state) {
case ANETZ_GESPRAECH:
PDEBUG(DANETZ, DEBUG_NOTICE, "Outgoing release, during call, going idle!\n");
anetz_go_idle(anetz);
break;
case ANETZ_ANRUF:
PDEBUG(DANETZ, DEBUG_NOTICE, "Outgoing release, during alerting, going idle!\n");
anetz_go_idle(anetz);
break;
default:
break;
}
}
/* Receive audio from call instance. */
void call_rx_audio(int callref, int16_t *samples, int count)
{
sender_t *sender;
anetz_t *anetz;
for (sender = sender_head; sender; sender = sender->next) {
anetz = (anetz_t *) sender;
if (sender->callref == callref)
break;
}
if (!sender)
return;
if (anetz->dsp_mode == DSP_MODE_AUDIO) {
int16_t up[count * anetz->sender.srstate.factor];
count = samplerate_upsample(&anetz->sender.srstate, samples, count, up);
jitter_save(&anetz->sender.audio, up, count);
}
}