app_echo.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[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 Echo application -- play back what you hear to evaluate latency
 *
 * \author Mark Spencer <[email protected]>
 *
 * \ingroup applications
 */

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

#include "asterisk.h"

#include "asterisk/file.h"
#include "asterisk/module.h"
#include "asterisk/channel.h"

/*** DOCUMENTATION
   <application name="Echo" language="en_US">
      <synopsis>
         Echo media, DTMF back to the calling party
      </synopsis>
      <syntax />
      <description>
         <para>Echos back any media or DTMF frames read from the calling
         channel back to itself. This will not echo CONTROL, MODEM, or NULL
         frames. Note: If '#' detected application exits.</para>
         <para>This application does not automatically answer and should be
         preceeded by an application such as Answer() or Progress().</para>
      </description>
   </application>
 ***/

static const char app[] = "Echo";

static int echo_exec(struct ast_channel *chan, const char *data)
{
   int res = -1;
   int fir_sent = 0;

   while (ast_waitfor(chan, -1) > -1) {
      struct ast_frame *f = ast_read(chan);
      if (!f) {
         break;
      }
      f->delivery.tv_sec = 0;
      f->delivery.tv_usec = 0;
      if (f->frametype == AST_FRAME_CONTROL
         && f->subclass.integer == AST_CONTROL_VIDUPDATE
         && !fir_sent) {
         if (ast_write(chan, f) < 0) {
            ast_frfree(f);
            goto end;
         }
         fir_sent = 1;
      }
      if (!fir_sent && f->frametype == AST_FRAME_VIDEO) {
         struct ast_frame frame = {
            .frametype = AST_FRAME_CONTROL,
            .subclass.integer = AST_CONTROL_VIDUPDATE,
         };
         ast_write(chan, &frame);
         fir_sent = 1;
      }
      if (f->frametype != AST_FRAME_CONTROL
         && f->frametype != AST_FRAME_MODEM
         && f->frametype != AST_FRAME_NULL
         && ast_write(chan, f)) {
         ast_frfree(f);
         goto end;
      }
      if ((f->frametype == AST_FRAME_DTMF) && (f->subclass.integer == '#')) {
         res = 0;
         ast_frfree(f);
         goto end;
      }
      ast_frfree(f);
   }
end:
   return res;
}

static int unload_module(void)
{
   return ast_unregister_application(app);
}

static int load_module(void)
{
   return ast_register_application_xml(app, echo_exec);
}

AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Simple Echo Application");