res_mutestream.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2009, Olle E. Johansson
 *
 * Olle E. Johansson <oej@edvina.net>
 *
 * 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 MUTESTREAM audiohooks
 *
 * \author Olle E. Johansson <oej@edvina.net>
 *
 *  \ingroup functions
 *
 * \note This module only handles audio streams today, but can easily be appended to also
 * zero out text streams if there's an application for it.
 * When we know and understands what happens if we zero out video, we can do that too.
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 89545 $")

#include "asterisk/options.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/module.h"
#include "asterisk/config.h"
#include "asterisk/file.h"
#include "asterisk/pbx.h"
#include "asterisk/frame.h"
#include "asterisk/utils.h"
#include "asterisk/audiohook.h"
#include "asterisk/manager.h"

/*** DOCUMENTATION
   <function name="MUTEAUDIO" language="en_US">
      <synopsis>
         Muting audio streams in the channel
      </synopsis>
      <syntax>
         <parameter name="direction" required="true">
            <para>Must be one of </para>
            <enumlist>
               <enum name="in">
                  <para>Inbound stream (to the PBX)</para>
               </enum>
               <enum name="out">
                  <para>Outbound stream (from the PBX)</para>
               </enum>
               <enum name="all">
                  <para>Both streams</para>
               </enum>
            </enumlist>
         </parameter>
      </syntax>
      <description>
         <para>The MUTEAUDIO function can be used to mute inbound (to the PBX) or outbound audio in a call.
         </para>
         <para>Examples:
         </para>
         <para>
         MUTEAUDIO(in)=on
         </para>
         <para>
         MUTEAUDIO(in)=off
         </para>
      </description>
   </function>
   <manager name="MuteAudio" language="en_US">
      <synopsis>
         Mute an audio stream.
      </synopsis>
      <syntax>
         <xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
         <parameter name="Channel" required="true">
            <para>The channel you want to mute.</para>
         </parameter>
         <parameter name="Direction" required="true">
            <enumlist>
               <enum name="in">
                  <para>Set muting on inbound audio stream. (to the PBX)</para>
               </enum>
               <enum name="out">
                  <para>Set muting on outbound audio stream. (from the PBX)</para>
               </enum>
               <enum name="all">
                  <para>Set muting on inbound and outbound audio streams.</para>
               </enum>
            </enumlist>
         </parameter>
         <parameter name="State" required="true">
            <enumlist>
               <enum name="on">
                  <para>Turn muting on.</para>
               </enum>
               <enum name="off">
                  <para>Turn muting off.</para>
               </enum>
            </enumlist>
         </parameter>
      </syntax>
      <description>
         <para>Mute an incoming or outgoing audio stream on a channel.</para>
      </description>
   </manager>
 ***/


/*! Our own datastore */
struct mute_information {
   struct ast_audiohook audiohook;
   int mute_write;
   int mute_read;
};


/*! Datastore destroy audiohook callback */
static void destroy_callback(void *data)
{
   struct mute_information *mute = data;

   /* Destroy the audiohook, and destroy ourselves */
   ast_audiohook_destroy(&mute->audiohook);
   ast_free(mute);
   ast_module_unref(ast_module_info->self);
}

/*! \brief Static structure for datastore information */
static const struct ast_datastore_info mute_datastore = {
   .type = "mute",
   .destroy = destroy_callback
};

/*! \brief The callback from the audiohook subsystem. We basically get a frame to have fun with */
static int mute_callback(struct ast_audiohook *audiohook, struct ast_channel *chan, struct ast_frame *frame, enum ast_audiohook_direction direction)
{
   struct ast_datastore *datastore = NULL;
   struct mute_information *mute = 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;
   }

   ast_channel_lock(chan);
   /* Grab datastore which contains our mute information */
   if (!(datastore = ast_channel_datastore_find(chan, &mute_datastore, NULL))) {
      ast_channel_unlock(chan);
      ast_debug(2, "Can't find any datastore to use. Bad. \n");
      return 0;
   }

   mute = datastore->data;


   /* If this is audio then allow them to increase/decrease the gains */
   if (frame->frametype == AST_FRAME_VOICE) {
      ast_debug(2, "Audio frame - direction %s  mute READ %s WRITE %s\n", direction == AST_AUDIOHOOK_DIRECTION_READ ? "read" : "write", mute->mute_read ? "on" : "off", mute->mute_write ? "on" : "off");

      /* Based on direction of frame grab the gain, and confirm it is applicable */
      if ((direction == AST_AUDIOHOOK_DIRECTION_READ && mute->mute_read) || (direction == AST_AUDIOHOOK_DIRECTION_WRITE && mute->mute_write)) {
         /* Ok, we just want to reset all audio in this frame. Keep NOTHING, thanks. */
         ast_frame_clear(frame);
      }
   }
   ast_channel_unlock(chan);

   return 0;
}

/*! \brief Initialize mute hook on channel, but don't activate it
   \pre Assumes that the channel is locked
*/
static struct ast_datastore *initialize_mutehook(struct ast_channel *chan)
{
   struct ast_datastore *datastore = NULL;
   struct mute_information *mute = NULL;

   ast_debug(2, "Initializing new Mute Audiohook \n");

   /* Allocate a new datastore to hold the reference to this mute_datastore and audiohook information */
   if (!(datastore = ast_datastore_alloc(&mute_datastore, NULL))) {
      return NULL;
   }

   if (!(mute = ast_calloc(1, sizeof(*mute)))) {
      ast_datastore_free(datastore);
      return NULL;
   }
   ast_audiohook_init(&mute->audiohook, AST_AUDIOHOOK_TYPE_MANIPULATE, "Mute", AST_AUDIOHOOK_MANIPULATE_ALL_RATES);
   mute->audiohook.manipulate_callback = mute_callback;
   datastore->data = mute;
   return datastore;
}

/*! \brief Add or activate mute audiohook on channel
   Assumes channel is locked
*/
static int mute_add_audiohook(struct ast_channel *chan, struct mute_information *mute, struct ast_datastore *datastore)
{
   /* Activate the settings */
   ast_channel_datastore_add(chan, datastore);
   if (ast_audiohook_attach(chan, &mute->audiohook)) {
      ast_log(LOG_ERROR, "Failed to attach audiohook for muting channel %s\n", ast_channel_name(chan));
      return -1;
   }
   ast_module_ref(ast_module_info->self);
   ast_debug(2, "Initialized audiohook on channel %s\n", ast_channel_name(chan));
   return 0;
}

/*! \brief Mute dialplan function */
static int func_mute_write(struct ast_channel *chan, const char *cmd, char *data, const char *value)
{
   struct ast_datastore *datastore = NULL;
   struct mute_information *mute = NULL;
   int is_new = 0;
   int turnon;

   ast_channel_lock(chan);
   if (!(datastore = ast_channel_datastore_find(chan, &mute_datastore, NULL))) {
      if (!(datastore = initialize_mutehook(chan))) {
         ast_channel_unlock(chan);
         return 0;
      }
      is_new = 1;
   }
   mute = datastore->data;

   turnon = ast_true(value);
   if (!strcasecmp(data, "out")) {
      mute->mute_write = turnon;
      ast_debug(1, "%s channel - outbound \n", turnon ? "Muting" : "Unmuting");
   } else if (!strcasecmp(data, "in")) {
      mute->mute_read = turnon;
      ast_debug(1, "%s channel - inbound  \n", turnon ? "Muting" : "Unmuting");
   } else if (!strcasecmp(data,"all")) {
      mute->mute_write = mute->mute_read = turnon;
   }

   if (is_new) {
      if (mute_add_audiohook(chan, mute, datastore)) {
         /* Can't add audiohook - already printed error message */
         ast_datastore_free(datastore);
         ast_free(mute);
      }
   }
   ast_channel_unlock(chan);

   return 0;
}

/* Function for debugging - might be useful */
static struct ast_custom_function mute_function = {
   .name = "MUTEAUDIO",
   .write = func_mute_write,
};

static int manager_mutestream(struct mansession *s, const struct message *m)
{
   const char *channel = astman_get_header(m, "Channel");
   const char *id = astman_get_header(m,"ActionID");
   const char *state = astman_get_header(m,"State");
   const char *direction = astman_get_header(m,"Direction");
   char id_text[256];
   struct ast_channel *c = NULL;
   struct ast_datastore *datastore = NULL;
   struct mute_information *mute = NULL;
   int is_new = 0;
   int turnon;

   if (ast_strlen_zero(channel)) {
      astman_send_error(s, m, "Channel not specified");
      return 0;
   }
   if (ast_strlen_zero(state)) {
      astman_send_error(s, m, "State not specified");
      return 0;
   }
   if (ast_strlen_zero(direction)) {
      astman_send_error(s, m, "Direction not specified");
      return 0;
   }
   /* Ok, we have everything */

   c = ast_channel_get_by_name(channel);
   if (!c) {
      astman_send_error(s, m, "No such channel");
      return 0;
   }

   ast_channel_lock(c);

   if (!(datastore = ast_channel_datastore_find(c, &mute_datastore, NULL))) {
      if (!(datastore = initialize_mutehook(c))) {
         ast_channel_unlock(c);
         ast_channel_unref(c);
         astman_send_error(s, m, "Memory allocation failure");
         return 0;
      }
      is_new = 1;
   }
   mute = datastore->data;

   turnon = ast_true(state);
   if (!strcasecmp(direction, "in")) {
      mute->mute_read = turnon;
   } else if (!strcasecmp(direction, "out")) {
      mute->mute_write = turnon;
   } else if (!strcasecmp(direction, "all")) {
      mute->mute_read = mute->mute_write = turnon;
   }

   if (is_new) {
      if (mute_add_audiohook(c, mute, datastore)) {
         /* Can't add audiohook */
         ast_datastore_free(datastore);
         ast_free(mute);
         ast_channel_unlock(c);
         ast_channel_unref(c);
         astman_send_error(s, m, "Couldn't add mute audiohook");
         return 0;
      }
   }
   ast_channel_unlock(c);
   ast_channel_unref(c);

   if (!ast_strlen_zero(id)) {
      snprintf(id_text, sizeof(id_text), "ActionID: %s\r\n", id);
   } else {
      id_text[0] = '\0';
   }
   astman_append(s, "Response: Success\r\n"
      "%s"
      "\r\n", id_text);
   return 0;
}


static int load_module(void)
{
   int res;

   res = ast_custom_function_register(&mute_function);
   res |= ast_manager_register_xml("MuteAudio", EVENT_FLAG_SYSTEM, manager_mutestream);

   return (res ? AST_MODULE_LOAD_DECLINE : AST_MODULE_LOAD_SUCCESS);
}

static int unload_module(void)
{
   ast_custom_function_unregister(&mute_function);
   /* Unregister AMI actions */
   ast_manager_unregister("MuteAudio");

   return 0;
}

AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Mute audio stream resources");