app_stream_echo.c File Reference

Stream echo application. More...

#include "asterisk.h"
#include "asterisk/app.h"
#include "asterisk/conversions.h"
#include "asterisk/file.h"
#include "asterisk/module.h"
#include "asterisk/channel.h"
#include "asterisk/stream.h"

Include dependency graph for app_stream_echo.c:

Go to the source code of this file.

Functions
static void	__reg_module (void)
static void	__unreg_module (void)
struct ast_module *	AST_MODULE_SELF_SYM (void)
static int	load_module (void)
static int	stream_echo_exec (struct ast_channel *chan, const char *data)
static int	stream_echo_perform (struct ast_channel *chan, struct ast_stream_topology *topology, enum ast_media_type type)
static struct ast_stream_topology *	stream_echo_topology_alloc (struct ast_stream_topology *original, unsigned int num, enum ast_media_type type)
static int	stream_echo_write (struct ast_channel *chan, struct ast_frame *frame, enum ast_media_type type, int one_to_one)
static int	stream_echo_write_error (struct ast_channel *chan, struct ast_frame *frame, int pos)
static int	unload_module (void)

Variables
static struct ast_module_info	__mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "Stream Echo Application" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_DEFAULT, .support_level = AST_MODULE_SUPPORT_CORE, }
static const char	app [] = "StreamEcho"
static const struct ast_module_info *	ast_module_info = &__mod_info

Detailed Description

Stream echo application.

Author

Kevin Harwell kharw.nosp@m.ell@.nosp@m.digiu.nosp@m.m.co.nosp@m.m

Definition in file app_stream_echo.c.

Function Documentation

__reg_module()

static void __reg_module ( void  )

static

Definition at line 348 of file app_stream_echo.c.

__unreg_module()

static void __unreg_module ( void  )

static

Definition at line 348 of file app_stream_echo.c.

AST_MODULE_SELF_SYM()

struct ast_module * AST_MODULE_SELF_SYM

(

void

)

Definition at line 348 of file app_stream_echo.c.

load_module()

static int load_module ( void  )

static

Definition at line 343 of file app_stream_echo.c.

{
    return ast_register_application_xml(app, stream_echo_exec);
}

References app, ast_register_application_xml, and stream_echo_exec().

stream_echo_exec()

static int stream_echo_exec ( struct ast_channel *  chan, const char *  data  )

static

Definition at line 287 of file app_stream_echo.c.

{
    int res;
    unsigned int num = 0;
    enum ast_media_type type;
    char *parse;
    struct ast_stream_topology *topology;
 
    AST_DECLARE_APP_ARGS(args,
        AST_APP_ARG(num);
        AST_APP_ARG(type);
    );
 
    parse = ast_strdupa(data);
    AST_STANDARD_APP_ARGS(args, parse);
 
    if (ast_strlen_zero(args.num)) {
        /*
         * If a number is not given then no topology is to be created
         * and renegotiated. The app will just echo back each stream
         * received to itself.
         */
        return stream_echo_perform(chan, NULL, AST_MEDIA_TYPE_UNKNOWN);
    }
 
    if (ast_str_to_uint(args.num, &num)) {
        ast_log(LOG_ERROR, "Failed to parse the first parameter '%s' into a"
            " greater than or equal to zero\n", args.num);
        return -1;
    }
 
    type = ast_strlen_zero(args.type) ? AST_MEDIA_TYPE_VIDEO :
        ast_media_type_from_str(args.type);
 
    topology = stream_echo_topology_alloc(
        ast_channel_get_stream_topology(chan), num, type);
    if (!topology) {
        ast_log(LOG_ERROR, "Unable to create '%u' streams of type '%s' to"
            " the topology\n", num, ast_codec_media_type2str(type));
        return -1;
    }
 
    res = stream_echo_perform(chan, topology, type);
 
    if (ast_channel_get_stream_topology(chan) != topology) {
        ast_stream_topology_free(topology);
    }
 
    return res;
}

References args, AST_APP_ARG, ast_channel_get_stream_topology(), ast_codec_media_type2str(), AST_DECLARE_APP_ARGS, ast_log, ast_media_type_from_str(), AST_MEDIA_TYPE_UNKNOWN, AST_MEDIA_TYPE_VIDEO, AST_STANDARD_APP_ARGS, ast_str_to_uint(), ast_strdupa, ast_stream_topology_free(), ast_strlen_zero(), LOG_ERROR, NULL, stream_echo_perform(), stream_echo_topology_alloc(), and type.

Referenced by load_module().

stream_echo_perform()

static int stream_echo_perform ( struct ast_channel *  chan, struct ast_stream_topology *  topology, enum ast_media_type  type  )

static

Definition at line 157 of file app_stream_echo.c.

{
    int update_sent = 0;
    int request_change = topology != NULL;
    int one_to_one = 1;
 
    while (ast_waitfor(chan, -1) > -1) {
        struct ast_frame *f;
 
        if (request_change) {
            /* Request a change to the new topology */
            if (ast_channel_request_stream_topology_change(chan, topology, NULL)) {
                ast_log(LOG_WARNING, "Request stream topology change not supported "
                    "by channel '%s'\n", ast_channel_name(chan));
            }
            request_change = 0;
        }
 
        f = ast_read_stream(chan);
        if (!f) {
            return -1;
        }
 
        if ((f->frametype == AST_FRAME_DTMF) && (f->subclass.integer == '#')) {
            ast_frfree(f);
            break;
        }
 
        f->delivery.tv_sec = 0;
        f->delivery.tv_usec = 0;
 
        if (f->frametype == AST_FRAME_CONTROL) {
            if (f->subclass.integer == AST_CONTROL_VIDUPDATE && !update_sent) {
                if (stream_echo_write(chan, f, type, one_to_one)) {
                    ast_frfree(f);
                    return -1;
                }
                update_sent = 1;
            } else if (f->subclass.integer == AST_CONTROL_SRCCHANGE) {
                update_sent = 0;
            } else if (f->subclass.integer == AST_CONTROL_STREAM_TOPOLOGY_CHANGED) {
                update_sent = 0;
                one_to_one = 0; /* Switch writing to one to many */
            }
        } else if (f->frametype == AST_FRAME_VIDEO && !update_sent){
            struct ast_frame frame = {
                .frametype = AST_FRAME_CONTROL,
                .subclass.integer = AST_CONTROL_VIDUPDATE,
            };
            stream_echo_write(chan, &frame, type, one_to_one);
            update_sent = 1;
        }
 
        if (f->frametype != AST_FRAME_CONTROL &&
            f->frametype != AST_FRAME_MODEM &&
            f->frametype != AST_FRAME_NULL &&
            stream_echo_write(chan, f, type, one_to_one)) {
            ast_frfree(f);
            return -1;
        }
 
        ast_frfree(f);
    }
 
    return 0;
}

References ast_channel_name(), ast_channel_request_stream_topology_change(), AST_CONTROL_SRCCHANGE, AST_CONTROL_STREAM_TOPOLOGY_CHANGED, AST_CONTROL_VIDUPDATE, AST_FRAME_CONTROL, AST_FRAME_DTMF, AST_FRAME_MODEM, AST_FRAME_NULL, AST_FRAME_VIDEO, ast_frfree, ast_log, ast_read_stream(), ast_waitfor(), ast_frame::delivery, ast_frame::frametype, ast_frame_subclass::integer, LOG_WARNING, NULL, stream_echo_write(), ast_frame::subclass, and type.

Referenced by stream_echo_exec().

stream_echo_topology_alloc()

static struct ast_stream_topology * stream_echo_topology_alloc ( struct ast_stream_topology *  original, unsigned int  num, enum ast_media_type  type  )

static

Definition at line 225 of file app_stream_echo.c.

{
    int i, n = num;
    struct ast_stream_topology *res = ast_stream_topology_alloc();
 
    if (!res) {
        return NULL;
    }
 
    /*
     * Clone every stream of a type not matching the given one. If the type
     * matches clone only the first stream found for the given type. Then for
     * that stream clone it again up to num - 1 times. Ignore any other streams
     * of the same matched type in the original topology.
     *
     * So for instance if the original stream contains 1 audio stream and 2 video
     * streams (video stream 'A' and video stream 'B'), num is '3', and the given
     * type is 'video' then the resulting topology will contain a clone of the
     * audio stream along with 3 clones of video stream 'A'. Video stream 'B' is
     * not copied over.
     */
    for (i = 0; i < ast_stream_topology_get_count(original); ++i) {
        struct ast_stream *stream = ast_stream_topology_get_stream(original, i);
 
        if (!n && ast_stream_get_type(stream) == type) {
            /* Don't copy any[more] of the given type */
            continue;
        }
 
        if (ast_stream_get_state(stream) == AST_STREAM_STATE_REMOVED) {
            /* Don't copy removed/declined streams */
            continue;
        }
 
        do {
            stream = ast_stream_clone(stream, NULL);
 
            if (!stream || ast_stream_topology_append_stream(res, stream) < 0) {
                ast_stream_free(stream);
                ast_stream_topology_free(res);
                return NULL;
            }
 
            if (ast_stream_get_type(stream) != type) {
                /* Do not multiply non matching streams */
                break;
            }
 
            /*
             * Since num is not zero yet (i.e. this is first stream found to
             * match on the type) and the types match then loop num - 1 times
             * cloning the same stream.
             */
            ast_stream_set_state(stream, n == num ?
                 AST_STREAM_STATE_SENDRECV : AST_STREAM_STATE_SENDONLY);
        } while (--n);
    }
 
    return res;
}

References ast_stream_clone(), ast_stream_free(), ast_stream_get_state(), ast_stream_get_type(), ast_stream_set_state(), AST_STREAM_STATE_REMOVED, AST_STREAM_STATE_SENDONLY, AST_STREAM_STATE_SENDRECV, ast_stream_topology_alloc(), ast_stream_topology_append_stream(), ast_stream_topology_free(), ast_stream_topology_get_count(), ast_stream_topology_get_stream(), NULL, and type.

Referenced by stream_echo_exec().

stream_echo_write()

static int stream_echo_write ( struct ast_channel *  chan, struct ast_frame *  frame, enum ast_media_type  type, int  one_to_one  )

static

Definition at line 102 of file app_stream_echo.c.

{
    int i;
    int num;
    struct ast_stream_topology *topology;
 
    /*
     * Since this is an echo application if we get a frame in on a stream
     * we simply want to echo it back out onto the same stream number.
     */
    num = ast_channel_is_multistream(chan) ? frame->stream_num : -1;
    if (ast_write_stream(chan, num, frame)) {
        return stream_echo_write_error(chan, frame, num);
    }
 
    /*
     * If the frame's type and given type don't match, or we are operating in
     * a one to one stream echo mode then there is nothing left to do.
     *
     * Note, if the channel is not multi-stream capable then one_to_one will
     * always be true, so it is safe to also not check for that here too.
     */
    if (one_to_one || !frame->subclass.format ||
        ast_format_get_type(frame->subclass.format) != type) {
        return 0;
    }
 
    /*
     * However, if we are operating in a single stream echoed to many stream
     * mode, and the frame's type matches the given type then we also need to
     * find the other streams of the same type and write out to those streams
     * as well.
     *
     * If we are here, then it's accepted that whatever stream number the frame
     * was read from for the given type is the only one set to send/receive,
     * while the others of the same type are set to receive only. Since we
     * shouldn't assume any order to the streams, we'll loop back through all
     * streams in the channel's topology writing only to those of the same type.
     * And, of course also not the stream which has already been written to.
     */
    topology = ast_channel_get_stream_topology(chan);
 
    for (i = 0; i < ast_stream_topology_get_count(topology); ++i) {
        struct ast_stream *stream = ast_stream_topology_get_stream(topology, i);
        if (num != i && ast_stream_get_type(stream) == type) {
            if (ast_write_stream(chan, i, frame)) {
                return stream_echo_write_error(chan, frame, i);
            }
        }
    }
 
    return 0;
}

References ast_channel_get_stream_topology(), ast_channel_is_multistream(), ast_format_get_type(), ast_stream_get_type(), ast_stream_topology_get_count(), ast_stream_topology_get_stream(), ast_write_stream(), ast_frame_subclass::format, stream_echo_write_error(), ast_frame::stream_num, ast_frame::subclass, and type.

Referenced by stream_echo_perform().

stream_echo_write_error()

static int stream_echo_write_error ( struct ast_channel *  chan, struct ast_frame *  frame, int  pos  )

static

Definition at line 81 of file app_stream_echo.c.

{
    char frame_type[32];
    const char *media_type;
    struct ast_stream *stream;
 
    ast_frame_type2str(frame->frametype, frame_type, sizeof(frame_type));
 
    stream = pos < 0 ?
        ast_channel_get_default_stream(chan, ast_format_get_type(frame->subclass.format)) :
        ast_stream_topology_get_stream(ast_channel_get_stream_topology(chan), pos);
 
    media_type = ast_codec_media_type2str(ast_stream_get_type(stream));
 
    ast_log(LOG_ERROR, "%s - unable to write frame type '%s' to stream type '%s' at "
        "position '%d'\n", ast_channel_name(chan), frame_type, media_type,
        ast_stream_get_position(stream));
 
    return -1;
}

References ast_channel_get_default_stream(), ast_channel_get_stream_topology(), ast_channel_name(), ast_codec_media_type2str(), ast_format_get_type(), ast_frame_type2str(), ast_log, ast_stream_get_position(), ast_stream_get_type(), ast_stream_topology_get_stream(), ast_frame_subclass::format, ast_frame::frametype, LOG_ERROR, and ast_frame::subclass.

Referenced by stream_echo_write().

unload_module()

static int unload_module ( void  )

static

Definition at line 338 of file app_stream_echo.c.

{
    return ast_unregister_application(app);
}

References app, and ast_unregister_application().

Variable Documentation

__mod_info

struct ast_module_info __mod_info = { .name = AST_MODULE, .flags = AST_MODFLAG_LOAD_ORDER , .description = "Stream Echo Application" , .key = "This paragraph is copyright (c) 2006 by Digium, Inc. \In order for your module to load, it must return this \key via a function called \"key\". Any code which \includes this paragraph must be licensed under the GNU \General Public License version 2 or later (at your \option). In addition to Digium's general reservations \of rights, Digium expressly reserves the right to \allow other parties to license this paragraph under \different terms. Any use of Digium, Inc. trademarks or \logos (including \"Asterisk\" or \"Digium\") without \express written permission of Digium, Inc. is prohibited.\n" , .buildopt_sum = AST_BUILDOPT_SUM, .load = load_module, .unload = unload_module, .load_pri = AST_MODPRI_DEFAULT, .support_level = AST_MODULE_SUPPORT_CORE, }

static

Definition at line 348 of file app_stream_echo.c.

app

const char app[] = "StreamEcho"

static

Definition at line 79 of file app_stream_echo.c.

Referenced by load_module(), and unload_module().

ast_module_info

const struct ast_module_info* ast_module_info = &__mod_info

static

Definition at line 348 of file app_stream_echo.c.