app_echo.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * 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 <markster@digium.com>
 *
 * \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");