app_tonedetect.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2021, Naveen Albert
 *
 * Naveen Albert <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Tone detection module
 *
 * \author Naveen Albert <[email protected]>
 *
 * \ingroup applications
 */

/*** MODULEINFO
   <support_level>extended</support_level>
 ***/

#include "asterisk.h"

#include <math.h>

#include "asterisk/module.h"
#include "asterisk/frame.h"
#include "asterisk/format_cache.h"
#include "asterisk/channel.h"
#include "asterisk/dsp.h"
#include "asterisk/pbx.h"
#include "asterisk/audiohook.h"
#include "asterisk/app.h"
#include "asterisk/indications.h"
#include "asterisk/conversions.h"

/*** DOCUMENTATION
   <application name="WaitForTone" language="en_US">
      <synopsis>
         Wait for tone
      </synopsis>
      <syntax>
         <parameter name="freq" required="true">
            <para>Frequency of the tone to wait for. If the tone consists of
            two frequencies, separate with the <literal>+</literal> symbol.
            Detection may be less accurate for multiple frequencies.</para>
         </parameter>
         <parameter name="duration_ms" required="false">
            <para>Minimum duration of tone, in ms. Default is 500ms.
            Using a minimum duration under 50ms is unlikely to produce
            accurate results.</para>
         </parameter>
         <parameter name="timeout" required="false">
            <para>Maximum amount of time, in seconds, to wait for specified tone.
            Default is forever.</para>
         </parameter>
         <parameter name="times" required="false">
            <para>Number of times the tone should be detected (subject to the
            provided timeout) before returning. Default is 1.</para>
         </parameter>
         <parameter name="options" required="false">
            <optionlist>
               <option name="d">
                  <para>Custom decibel threshold to use. Default is 16.</para>
               </option>
               <option name="s">
                  <para>Squelch tone.</para>
               </option>
            </optionlist>
         </parameter>
      </syntax>
      <description>
         <para>Waits for a tone to be detected before dialplan execution continues.</para>
         <variablelist>
         <variable name="WAITFORTONESTATUS">
            <para>This indicates the result of the wait.</para>
            <value name="SUCCESS"/>
            <value name="ERROR"/>
            <value name="TIMEOUT"/>
            <value name="HANGUP"/>
         </variable>
      </variablelist>
      </description>
      <see-also>
         <ref type="application">PlayTones</ref>
      </see-also>
   </application>
   <function name="TONE_DETECT" language="en_US">
      <synopsis>
         Asynchronously detects a tone
      </synopsis>
      <syntax>
         <parameter name="freq" required="true">
            <para>Frequency of the tone to wait for. If the tone consists of
            two frequencies, separate with the <literal>+</literal> symbol.
            Detection may be less accurate for multiple frequencies.</para>
         </parameter>
         <parameter name="duration_ms" required="false">
            <para>Minimum duration of tone, in ms. Default is 500ms.
            Using a minimum duration under 50ms is unlikely to produce
            accurate results.</para>
         </parameter>
         <parameter name="options">
            <optionlist>
               <option name="d">
                  <para>Custom decibel threshold to use. Default is 16.</para>
               </option>
               <option name="g">
                  <para>Go to the specified context,exten,priority if tone is received on this channel.
                  Detection will not end automatically.</para>
               </option>
               <option name="h">
                  <para>Go to the specified context,exten,priority if tone is transmitted on this channel.
                  Detection will not end automatically.</para>
               </option>
               <option name="r">
                  <para>Apply to received frames only. Default is both directions.</para>
               </option>
               <option name="s">
                  <para>Squelch tone.</para>
               </option>
               <option name="t">
                  <para>Apply to transmitted frames only. Default is both directions.</para>
               </option>
               <option name="x">
                  <para>Destroy the detector (stop detection).</para>
               </option>
            </optionlist>
         </parameter>
      </syntax>
      <description>
         <para>The TONE_DETECT function detects a tone of one or two frequencies and keeps
         track of how many times the tone has been detected.</para>
         <para>When reading this function (instead of writing), supply <literal>tx</literal>
         to get the number of times a tone has been detected in the TX direction and
         <literal>rx</literal> to get the number of times a tone has been detected in the
         RX direction.</para>
         <example title="intercept2600">
         same => n,Set(TONE_DETECT(2600,1000,g(got-2600,s,1))=)
         same => n,Wait(15)
         same => n,NoOp(${TONE_DETECT(rx)})
         </example>
      </description>
   </function>
 ***/

struct detect_information {
   struct ast_dsp *dsp;
   struct ast_audiohook audiohook;
   int freq1;
   int freq2;
   int duration;
   int db;
   char *gototx;
   char *gotorx;
   unsigned short int squelch;
   unsigned short int tx;
   unsigned short int rx;
   int txcount;
   int rxcount;
};

enum td_opts {
   OPT_TX = (1 << 1),
   OPT_RX = (1 << 2),
   OPT_END_FILTER = (1 << 3),
   OPT_GOTO_RX = (1 << 4),
   OPT_GOTO_TX = (1 << 5),
   OPT_DECIBEL = (1 << 6),
   OPT_SQUELCH = (1 << 7),
};

enum {
   OPT_ARG_DECIBEL,
   OPT_ARG_GOTO_RX,
   OPT_ARG_GOTO_TX,
   /* note: this entry _MUST_ be the last one in the enum */
   OPT_ARG_ARRAY_SIZE,
};

AST_APP_OPTIONS(td_opts, {
   AST_APP_OPTION_ARG('d', OPT_DECIBEL, OPT_ARG_DECIBEL),
   AST_APP_OPTION_ARG('g', OPT_GOTO_RX, OPT_ARG_GOTO_RX),
   AST_APP_OPTION_ARG('h', OPT_GOTO_TX, OPT_ARG_GOTO_TX),
   AST_APP_OPTION('s', OPT_SQUELCH),
   AST_APP_OPTION('t', OPT_TX),
   AST_APP_OPTION('r', OPT_RX),
   AST_APP_OPTION('x', OPT_END_FILTER),
});

static void destroy_callback(void *data)
{
   struct detect_information *di = data;
   ast_dsp_free(di->dsp);
   if (di->gotorx) {
      ast_free(di->gotorx);
   }
   if (di->gototx) {
      ast_free(di->gototx);
   }
   ast_audiohook_lock(&di->audiohook);
   ast_audiohook_detach(&di->audiohook);
   ast_audiohook_unlock(&di->audiohook);
   ast_audiohook_destroy(&di->audiohook);
   ast_free(di);
   return;
}

static const struct ast_datastore_info detect_datastore = {
   .type = "detect",
   .destroy = destroy_callback
};

static int detect_callback(struct ast_audiohook *audiohook, struct ast_channel *chan, struct ast_frame *frame, enum ast_audiohook_direction direction)
{
   struct ast_datastore *datastore = NULL;
   struct detect_information *di = NULL;

   /* If the audiohook is stopping it means the channel is shutting down.... but we let the datastore destroy take care of it */
   if (audiohook->status == AST_AUDIOHOOK_STATUS_DONE)
      return 0;

   /* Grab datastore which contains our gain information */
   if (!(datastore = ast_channel_datastore_find(chan, &detect_datastore, NULL)))
      return 0;

   di = datastore->data;

   if (!frame || frame->frametype != AST_FRAME_VOICE)
      return 0;

   if (!(direction == AST_AUDIOHOOK_DIRECTION_READ ? &di->rx : &di->tx))
      return 0;

   /* we don't want to modify the original frame */
   if (!(frame = ast_frisolate(frame))) {
      return 0;
   }
   frame = ast_dsp_process(chan, di->dsp, frame);
   if (frame->frametype == AST_FRAME_DTMF) {
      char result = frame->subclass.integer;
      if (result == 'q') {
         ast_debug(1, "TONE_DETECT just got a hit\n");
         if (direction == AST_AUDIOHOOK_DIRECTION_READ)
            di->rxcount = di->rxcount + 1;
         else
            di->txcount = di->txcount + 1;
         if (direction == AST_AUDIOHOOK_DIRECTION_READ && di->gotorx) {
            ast_async_parseable_goto(chan, di->gotorx);
         } else if (di->gototx) {
            ast_async_parseable_goto(chan, di->gototx);
         }
      }
   }
   ast_frfree(frame);

   return 0;
}

static int remove_detect(struct ast_channel *chan)
{
   struct ast_datastore *datastore = NULL;
   struct detect_information *data;
   SCOPED_CHANNELLOCK(chan_lock, chan);

   datastore = ast_channel_datastore_find(chan, &detect_datastore, NULL);
   if (!datastore) {
      ast_log(AST_LOG_WARNING, "Cannot remove TONE_DETECT from %s: TONE_DETECT not currently enabled\n",
              ast_channel_name(chan));
      return -1;
   }
   data = datastore->data;

   if (ast_audiohook_remove(chan, &data->audiohook)) {
      ast_log(AST_LOG_WARNING, "Failed to remove TONE_DETECT audiohook from channel %s\n", ast_channel_name(chan));
      return -1;
   }

   if (ast_channel_datastore_remove(chan, datastore)) {
      ast_log(AST_LOG_WARNING, "Failed to remove TONE_DETECT datastore from channel %s\n",
              ast_channel_name(chan));
      return -1;
   }
   ast_datastore_free(datastore);

   return 0;
}

static int freq_parser(char *freqs, int *freq1, int *freq2) {
   char *f1, *f2, *f3;
   if (ast_strlen_zero(freqs)) {
      ast_log(LOG_ERROR, "No frequency specified\n");
      return -1;
   }
   f3 = ast_strdupa(freqs);
   f1 = strsep(&f3, "+");
   f2 = strsep(&f3, "+");
   if (!ast_strlen_zero(f3)) {
      ast_log(LOG_WARNING, "Only up to 2 frequencies may be specified: %s\n", freqs);
      return -1;
   }
   if (ast_str_to_int(f1, freq1)) {
      ast_log(LOG_WARNING, "Frequency must be an integer: %s\n", f1);
      return -1;
   }
   if (*freq1 < 1) {
      ast_log(LOG_WARNING, "Sorry, positive frequencies only: %d\n", *freq1);
      return -1;
   }
   if (!ast_strlen_zero(f2)) {
      ast_log(LOG_WARNING, "Sorry, currently only 1 frequency is supported\n");
      return -1;
      /* not supported just yet, but possibly will be in the future */
      if (ast_str_to_int(f2, freq2)) {
         ast_log(LOG_WARNING, "Frequency must be an integer: %s\n", f2);
         return -1;
      }
      if (*freq2 < 1) {
         ast_log(LOG_WARNING, "Sorry, positive frequencies only: %d\n", *freq2);
         return -1;
      }
   }
   return 0;
}

static char* goto_parser(struct ast_channel *chan, char *loc) {
   char *exten, *pri, *context, *parse;
   char *dest;
   int size;
   parse = ast_strdupa(loc);
   context = strsep(&parse, ",");
   exten = strsep(&parse, ",");
   pri = strsep(&parse, ",");
   if (!exten) {
      pri = context;
      exten = NULL;
      context = NULL;
   } else if (!pri) {
      pri = exten;
      exten = context;
      context = NULL;
   }
   ast_channel_lock(chan);
   if (ast_strlen_zero(exten)) {
      exten = ast_strdupa(ast_channel_exten(chan));
   }
   if (ast_strlen_zero(context)) {
      context = ast_strdupa(ast_channel_context(chan));
   }
   ast_channel_unlock(chan);
   
   /* size + 1 for null terminator + 2 commas */
   size = sizeof(context) + sizeof(exten) + sizeof(pri) + 2;
   dest = ast_malloc(size + 1);
   snprintf(dest, size, "%s,%s,%s", context, exten, pri);
   return dest;
}

static int detect_read(struct ast_channel *chan, const char *cmd, char *data, char *buffer, size_t buflen)
{
   struct ast_datastore *datastore = NULL;
   struct detect_information *di = NULL;

   if (!chan) {
      ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
      return -1;
   }

   ast_channel_lock(chan);
   if (!(datastore = ast_channel_datastore_find(chan, &detect_datastore, NULL))) {
      ast_channel_unlock(chan);
      return -1; /* function not initiated yet, so nothing to read */
   } else {
      ast_channel_unlock(chan);
      di = datastore->data;
   }

   if (strchr(data, 't')) {
      snprintf(buffer, buflen, "%d", di->txcount);
   } else if (strchr(data, 'r')) {
      snprintf(buffer, buflen, "%d", di->rxcount);
   } else {
      ast_log(LOG_WARNING, "Invalid direction: %s\n", data);
   }

   return 0;
}

static int detect_write(struct ast_channel *chan, const char *cmd, char *data, const char *value)
{
   char *parse;
   struct ast_datastore *datastore = NULL;
   struct detect_information *di = NULL;
   int is_new = 0;
   struct ast_flags flags = { 0 };
   char *opt_args[OPT_ARG_ARRAY_SIZE];
   struct ast_dsp *dsp;
   int freq1 = 0, freq2 = 0, duration = 500, db = 16, squelch = 0;

   AST_DECLARE_APP_ARGS(args,
      AST_APP_ARG(freqs);
      AST_APP_ARG(duration);
      AST_APP_ARG(options);
   );

   if (!chan) {
      ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
      return -1;
   }
   parse = ast_strdupa(data);
   AST_STANDARD_APP_ARGS(args, parse);

   ast_channel_lock(chan);
   if (!(datastore = ast_channel_datastore_find(chan, &detect_datastore, NULL))) {
      ast_channel_unlock(chan);
      if (!(datastore = ast_datastore_alloc(&detect_datastore, NULL)))
         return 0;
      if (!(di = ast_calloc(1, sizeof(*di)))) {
         ast_datastore_free(datastore);
         return 0;
      }
      ast_audiohook_init(&di->audiohook, AST_AUDIOHOOK_TYPE_MANIPULATE, "Tone Detector", AST_AUDIOHOOK_MANIPULATE_ALL_RATES);
      di->audiohook.manipulate_callback = detect_callback;
      is_new = 1;
   } else {
      ast_channel_unlock(chan);
      di = datastore->data;
   }

   if (!ast_strlen_zero(args.options)) {
      ast_app_parse_options(td_opts, &flags, opt_args, args.options);
   }

   if (ast_test_flag(&flags, OPT_END_FILTER)) {
      return remove_detect(chan);
   }
   if (freq_parser(args.freqs, &freq1, &freq2)) {
      return -1;
   }
   if (!ast_strlen_zero(args.duration) && (ast_str_to_int(args.duration, &duration) || duration < 1)) {
      ast_log(LOG_WARNING, "Invalid duration: %s\n", args.duration);
      return -1;
   }
   di->duration = duration;
   if (ast_test_flag(&flags, OPT_DECIBEL) && !ast_strlen_zero(opt_args[OPT_ARG_DECIBEL])) {
      if ((ast_str_to_int(opt_args[OPT_ARG_DECIBEL], &db) || db < 1)) {
         ast_log(LOG_WARNING, "Invalid decibel level: %s\n", opt_args[OPT_ARG_DECIBEL]);
         return -1;
      }
   }
   di->gotorx = NULL;
   di->gototx = NULL;
   /* resolve gotos now, in case a full context,exten,pri wasn't specified */
   if (ast_test_flag(&flags, OPT_GOTO_RX) && !ast_strlen_zero(opt_args[OPT_ARG_GOTO_RX])) {
      di->gotorx = goto_parser(chan, opt_args[OPT_ARG_GOTO_RX]);
   }
   if (ast_test_flag(&flags, OPT_GOTO_TX) && !ast_strlen_zero(opt_args[OPT_ARG_GOTO_TX])) {
      di->gototx = goto_parser(chan, opt_args[OPT_ARG_GOTO_TX]);
   }
   di->db = db;
   di->squelch = ast_test_flag(&flags, OPT_SQUELCH);

   di->tx = 1;
   di->rx = 1;
   if (ast_strlen_zero(args.options) || ast_test_flag(&flags, OPT_TX)) {
      di->tx = 1;
      di->rx = 0;
   }
   if (ast_strlen_zero(args.options) || ast_test_flag(&flags, OPT_RX)) {
      di->rx = 1;
      di->tx = 0;
   }

   if (is_new) {
      if (!(dsp = ast_dsp_new())) {
         ast_log(LOG_WARNING, "Unable to allocate DSP!\n");
         return -1;
      }
      ast_dsp_set_features(dsp, DSP_FEATURE_FREQ_DETECT);
      ast_dsp_set_freqmode(dsp, freq1, duration, db, squelch);
      di->dsp = dsp;
      di->txcount = 0;
      di->rxcount = 0;
      ast_debug(1, "Keeping our ears open for %s Hz, %d db\n", args.freqs, db);
      datastore->data = di;
      ast_channel_lock(chan);
      ast_channel_datastore_add(chan, datastore);
      ast_channel_unlock(chan);
      ast_audiohook_attach(chan, &di->audiohook);
   } else {
      dsp = di->dsp;
      ast_dsp_set_freqmode(dsp, freq1, duration, db, squelch);
   }

   return 0;
}

enum {
   OPT_APP_DECIBEL =  (1 << 0),
   OPT_APP_SQUELCH =  (1 << 1),
};

enum {
   OPT_APP_ARG_DECIBEL,
   /* note: this entry _MUST_ be the last one in the enum */
   OPT_APP_ARG_ARRAY_SIZE,
};

AST_APP_OPTIONS(wait_exec_options, BEGIN_OPTIONS
   AST_APP_OPTION_ARG('d', OPT_APP_DECIBEL, OPT_APP_ARG_DECIBEL),
   AST_APP_OPTION('s', OPT_APP_SQUELCH),
END_OPTIONS);

static int wait_exec(struct ast_channel *chan, const char *data)
{
   char *appdata;
   struct ast_flags flags = {0};
   char *opt_args[OPT_APP_ARG_ARRAY_SIZE];
   double timeoutf = 0;
   int freq1 = 0, freq2 = 0, timeout = 0, duration = 500, times = 1, db = 16, squelch = 0;
   struct ast_frame *frame = NULL;
   struct ast_dsp *dsp;
   struct timeval start;
   int remaining_time = 0;
   int hits = 0;
   AST_DECLARE_APP_ARGS(args,
      AST_APP_ARG(freqs);
      AST_APP_ARG(duration);
      AST_APP_ARG(timeout);
      AST_APP_ARG(times);
      AST_APP_ARG(options);
   );

   appdata = ast_strdupa(data);
   AST_STANDARD_APP_ARGS(args, appdata);

   if (!ast_strlen_zero(args.options)) {
      ast_app_parse_options(wait_exec_options, &flags, opt_args, args.options);
   }
   if (freq_parser(args.freqs, &freq1, &freq2)) {
      pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "ERROR");
      return -1;
   }
   if (!ast_strlen_zero(args.timeout) && (sscanf(args.timeout, "%30lf", &timeoutf) != 1 || timeout < 0)) {
      ast_log(LOG_WARNING, "Invalid timeout: %s\n", args.timeout);
      pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "ERROR");
      return -1;
   }
   timeout = 1000 * timeoutf;
   if (!ast_strlen_zero(args.duration) && (ast_str_to_int(args.duration, &duration) || duration < 1)) {
      ast_log(LOG_WARNING, "Invalid duration: %s\n", args.duration);
      pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "ERROR");
      return -1;
   }
   if (!ast_strlen_zero(args.times) && (ast_str_to_int(args.times, &times) || times < 1)) {
      ast_log(LOG_WARNING, "Invalid number of times: %s\n", args.times);
      pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "ERROR");
      return -1;
   }
   if (ast_test_flag(&flags, OPT_APP_DECIBEL) && !ast_strlen_zero(opt_args[OPT_APP_ARG_DECIBEL])) {
      if ((ast_str_to_int(opt_args[OPT_APP_ARG_DECIBEL], &db) || db < 1)) {
         ast_log(LOG_WARNING, "Invalid decibel level: %s\n", opt_args[OPT_APP_ARG_DECIBEL]);
         pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "ERROR");
         return -1;
      }
   }
   squelch = ast_test_flag(&flags, OPT_APP_SQUELCH);
   if (!(dsp = ast_dsp_new())) {
      ast_log(LOG_WARNING, "Unable to allocate DSP!\n");
      pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "ERROR");
      return -1;
   }
   ast_dsp_set_features(dsp, DSP_FEATURE_FREQ_DETECT);
   ast_dsp_set_freqmode(dsp,  freq1, duration, db, squelch);
   ast_debug(1, "Waiting for %s Hz, %d time(s), timeout %d ms, %d db\n", args.freqs, times, timeout, db);
   start = ast_tvnow();
   while (timeout == 0 || remaining_time > 0) {
      if (timeout > 0) {
         remaining_time = ast_remaining_ms(start, timeout);
         if (remaining_time <= 0) {
            pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "TIMEOUT");
            break;
         }
      }
      if (ast_waitfor(chan, 1000) > 0) {
         if (!(frame = ast_read(chan))) {
            ast_debug(1, "Channel '%s' did not return a frame; probably hung up.\n", ast_channel_name(chan));
            pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "HANGUP");
            break;
         } else if (frame->frametype == AST_FRAME_VOICE) {
            frame = ast_dsp_process(chan, dsp, frame);
            if (frame->frametype == AST_FRAME_DTMF) {
               char result = frame->subclass.integer;
               if (result == 'q') {
                  hits++;
                  ast_debug(1, "We just detected %s Hz (hit #%d)\n", args.freqs, hits);
                  if (hits >= times) {
                     pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "SUCCESS");
                     break;
                  }
               }
            }
         }
      } else {
         pbx_builtin_setvar_helper(chan, "WAITFORTONESTATUS", "HANGUP");
      }
   }
   ast_dsp_free(dsp);

   return 0;
}

static char *waitapp = "WaitForTone";

static struct ast_custom_function detect_function = {
   .name = "TONE_DETECT",
   .read = detect_read,
   .write = detect_write,
};

static int unload_module(void)
{
   int res;

   res = ast_unregister_application(waitapp);
   res |= ast_custom_function_unregister(&detect_function);

   return res;
}

static int load_module(void)
{
   int res;

   res = ast_register_application_xml(waitapp, wait_exec);
   res |= ast_custom_function_register(&detect_function);

   return res;
}

AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "Tone detection module");