asterisk/apps/app_dtmfstore.c

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2023-05-25 18:45:57 +00:00
/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2021, Naveen Albert
*
* Naveen Albert <asterisk@phreaknet.org>
*
* 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 Technology independent asynchronous DTMF collection
*
* \author Naveen Albert <asterisk@phreaknet.org>
*
* \ingroup functions
*
*/
/*** MODULEINFO
<support_level>extended</support_level>
***/
#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/framehook.h"
#include "asterisk/app.h"
#include "asterisk/conversions.h"
/*** DOCUMENTATION
<application name="StoreDTMF" language="en_US">
<since>
<version>16.20.0</version>
<version>18.6.0</version>
<version>19.0.0</version>
</since>
<synopsis>
Stores DTMF digits transmitted or received on a channel.
</synopsis>
<syntax>
<parameter name="direction" required="true">
<para>Must be <literal>TX</literal> or <literal>RX</literal> to
store digits, or <literal>remove</literal> to disable.</para>
</parameter>
</syntax>
<description>
<para>The StoreDTMF function can be used to obtain digits sent in the
<literal>TX</literal> or <literal>RX</literal> direction of any channel.</para>
<para>The arguments are:</para>
<para><replaceable>var_name</replaceable>: Name of variable to which to append
digits.</para>
<para><replaceable>max_digits</replaceable>: The maximum number of digits to
store in the variable. Defaults to 0 (no maximum). After reading <literal>
maximum</literal> digits, no more digits will be stored.</para>
<example title="Store digits in CDR variable">
same => n,StoreDTMF(TX,CDR(digits))
</example>
<example title="Store up to 24 digits">
same => n,StoreDTMF(RX,testvar,24)
</example>
<example title="Disable digit collection">
same => n,StoreDTMF(remove)
</example>
</description>
</application>
***/
static char *app = "StoreDTMF";
/*! \brief Private data structure used with the function's datastore */
struct dtmf_store_data {
int framehook_id;
char *rx_var;
char *tx_var;
int maxdigits;
};
static void datastore_destroy_cb(void *data) {
struct dtmf_store_data *d;
d = data;
if (d) {
if (d->rx_var) {
ast_free(d->rx_var);
}
if (d->tx_var) {
ast_free(d->tx_var);
}
ast_free(data);
}
}
/*! \brief The channel datastore the function uses to store state */
static const struct ast_datastore_info dtmf_store_datastore = {
.type = "dtmf_store",
.destroy = datastore_destroy_cb
};
/*! \internal \brief Store digits tx/rx on the channel */
static int remove_dtmf_store(struct ast_channel *chan)
{
struct ast_datastore *datastore = NULL;
struct dtmf_store_data *data;
SCOPED_CHANNELLOCK(chan_lock, chan);
datastore = ast_channel_datastore_find(chan, &dtmf_store_datastore, NULL);
if (!datastore) {
ast_log(AST_LOG_WARNING, "Cannot remove StoreDTMF from %s: StoreDTMF not currently enabled\n",
ast_channel_name(chan));
return -1;
}
data = datastore->data;
if (ast_framehook_detach(chan, data->framehook_id)) {
ast_log(AST_LOG_WARNING, "Failed to remove StoreDTMF framehook 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 StoreDTMF datastore from channel %s\n",
ast_channel_name(chan));
return -1;
}
ast_datastore_free(datastore);
return 0;
}
/*! \brief Frame hook that is called to intercept digit/undigit */
static struct ast_frame *dtmf_store_framehook(struct ast_channel *chan,
struct ast_frame *f, enum ast_framehook_event event, void *data)
{
char currentdata[512];
char varnamesub[64];
char *varname = NULL;
struct dtmf_store_data *framedata = data;
int len;
if (!f || !framedata) {
return f;
}
if ((event != AST_FRAMEHOOK_EVENT_WRITE) && (event != AST_FRAMEHOOK_EVENT_READ)) {
return f;
}
if (f->frametype != AST_FRAME_DTMF_END) {
return f;
}
/* If this is DTMF then store the digits */
if (event == AST_FRAMEHOOK_EVENT_READ && framedata->rx_var) { /* coming from source */
varname = framedata->rx_var;
} else if (event == AST_FRAMEHOOK_EVENT_WRITE && framedata->tx_var) { /* going to source */
varname = framedata->tx_var;
}
if (!varname) {
return f;
}
sprintf(varnamesub, "${%s}", varname);
pbx_substitute_variables_helper(chan, varnamesub, currentdata, 511);
/* pbx_builtin_getvar_helper works for regular vars but not CDR vars */
if (ast_strlen_zero(currentdata)) { /* var doesn't exist yet */
ast_debug(3, "Creating new digit store: %s\n", varname);
}
len = strlen(currentdata);
if (framedata->maxdigits > 0 && len >= framedata->maxdigits) {
ast_debug(3, "Reached digit limit: %d\n", framedata->maxdigits);
remove_dtmf_store(chan); /* reached max digit count, stop now */
return f;
} else {
char newdata[len + 2]; /* one more char + terminator */
if (len > 0) {
ast_copy_string(newdata, currentdata, len + 2);
}
newdata[len] = (unsigned) f->subclass.integer;
newdata[len + 1] = '\0';
ast_debug(3, "Appending to digit store: now %s\n", newdata);
pbx_builtin_setvar_helper(chan, varname, newdata);
}
return f;
}
/*! \internal \brief Enable digit interception on the channel */
static int dtmfstore_exec(struct ast_channel *chan, const char *appdata)
{
struct ast_datastore *datastore;
struct dtmf_store_data *data;
static struct ast_framehook_interface digit_framehook_interface = {
.version = AST_FRAMEHOOK_INTERFACE_VERSION,
.event_cb = dtmf_store_framehook,
.disable_inheritance = 1,
};
char *parse = ast_strdupa(appdata);
AST_DECLARE_APP_ARGS(args,
AST_APP_ARG(direction);
AST_APP_ARG(varname);
AST_APP_ARG(maxdigits);
);
SCOPED_CHANNELLOCK(chan_lock, chan);
AST_STANDARD_APP_ARGS(args, parse);
if (ast_strlen_zero(appdata)) {
ast_log(AST_LOG_WARNING, "StoreDTMF requires an argument\n");
return -1;
}
if (!strcasecmp(args.direction, "remove")) {
return remove_dtmf_store(chan);
}
datastore = ast_channel_datastore_find(chan, &dtmf_store_datastore, NULL);
if (datastore) {
ast_log(AST_LOG_WARNING, "StoreDTMF already set on '%s'\n",
ast_channel_name(chan));
return 0;
}
datastore = ast_datastore_alloc(&dtmf_store_datastore, NULL);
if (!datastore) {
return -1;
}
data = ast_calloc(1, sizeof(*data));
if (!data) {
ast_datastore_free(datastore);
return -1;
}
digit_framehook_interface.data = data;
data->rx_var = NULL;
data->tx_var = NULL;
data->maxdigits = 0;
if (!strcasecmp(args.direction, "tx")) {
data->tx_var = ast_strdup(args.varname);
} else if (!strcasecmp(args.direction, "rx")) {
data->rx_var = ast_strdup(args.varname);
} else {
ast_log(LOG_ERROR, "Direction must be either RX or TX\n");
return -1;
}
if (!ast_strlen_zero(args.maxdigits)) {
if (ast_str_to_int(args.maxdigits,&(data->maxdigits))) {
ast_log(LOG_ERROR, "Invalid integer: %s\n", args.maxdigits);
return -1;
}
if (data->maxdigits < 0) {
ast_log(LOG_ERROR, "Invalid natural number: %d\n", data->maxdigits);
return -1;
} else if (data->maxdigits == 0) {
ast_log(LOG_WARNING, "No maximum digit count set\n");
}
}
data->framehook_id = ast_framehook_attach(chan, &digit_framehook_interface);
if (data->framehook_id < 0) {
ast_log(AST_LOG_WARNING, "Failed to attach StoreDTMF framehook to '%s'\n",
ast_channel_name(chan));
ast_datastore_free(datastore);
ast_free(data);
return -1;
}
datastore->data = data;
ast_channel_datastore_add(chan, datastore);
return 0;
}
static int unload_module(void)
{
return ast_unregister_application(app);
}
static int load_module(void)
{
return ast_register_application_xml(app, dtmfstore_exec);
}
AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "Technology independent async DTMF storage");