1 files changed, 339 insertions, 0 deletions
diff --git a/apps/app_stream_echo.c b/apps/app_stream_echo.c
new file mode 100644
index 000000000..53cbcd74d
--- /dev/null
+++ b/apps/app_stream_echo.c
@@ -0,0 +1,339 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2017, Digium, Inc.
+ *
+ * Kevin Harwell <kharwell@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 Stream echo application
+ *
+ * \author Kevin Harwell <kharwell@digium.com>
+ */
+
+/*** MODULEINFO
+	<support_level>core</support_level>
+ ***/
+
+#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"
+
+/*** DOCUMENTATION
+	<application name="StreamEcho" language="en_US">
+		<synopsis>
+			Echo media, up to 'N' streams of a type, and DTMF back to the calling party
+		</synopsis>
+		<syntax>
+		<parameter name="num" required="false">
+			<para>The number of streams of a type to echo back. If '0' is specified then
+			all streams of a type are removed.</para>
+		</parameter>
+		<parameter name="type" required="false">
+			<para>The media type of the stream(s) to add or remove (in the case of "num"
+			being '0'). This can be set to either "audio" or "video" (default). If "num"
+			is empty (i.e. not specified) then this parameter is ignored.</para>
+		</parameter>
+		</syntax>
+		<description>
+			<para>If a "num" (the number of streams) is not given then this simply echos
+			back any media or DTMF frames (note, however if '#' is detected then the
+			application exits) read from the calling channel back to itself. This means
+			for any relevant frame read from a particular stream it is written back out
+			to the associated write stream in a one to one fashion.
+			</para>
+			<para>However if a "num" is specified, and if the calling channel allows it
+			(a new offer is made requesting the allowance of additional streams) then any
+			any media received, like before, is echoed back onto each stream. However, in
+			this case a relevant frame received on a stream of the given "type" is also
+			echoed back out to the other streams of that same type. It should be noted that
+			when operating in this mode only the first stream found of the given "type" is
+			allowed from the original offer. And this first stream found is also the only
+			stream of that "type" granted read (send/receive) capabilities in the new offer
+			whereas the additional ones are set to receive only.</para>
+			<note><para>This does not echo CONTROL, MODEM, or NULL frames.</para></note>
+		</description>
+	</application>
+ ***/
+
+static const char app[] = "StreamEcho";
+
+static int stream_echo_write_error(struct ast_channel *chan, struct ast_frame *frame, int pos)
+{
+	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;
+}
+
+static int stream_echo_write(struct ast_channel *chan, struct ast_frame *frame,
+	enum ast_media_type type, int one_to_one)
+{
+	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 || 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;
+}
+
+static int stream_echo_perform(struct ast_channel *chan,
+	struct ast_stream_topology *topology, enum ast_media_type type)
+{
+	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(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, one_to_one, type)) {
+					ast_frfree(f);
+					return -1;
+				}
+				update_sent = 1;
+			} 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, one_to_one, type);
+			update_sent = 1;
+		}
+
+		if (f->frametype != AST_FRAME_CONTROL &&
+		    f->frametype != AST_FRAME_MODEM &&
+		    f->frametype != AST_FRAME_NULL &&
+		    stream_echo_write(chan, f, one_to_one, type)) {
+			ast_frfree(f);
+			return -1;
+		}
+
+		ast_frfree(f);
+	}
+
+	return 0;
+}
+
+static struct ast_stream_topology *stream_echo_topology_alloc(
+	struct ast_stream_topology *original, unsigned int num, enum ast_media_type type)
+{
+	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;
+		}
+
+		do {
+			stream = ast_stream_clone(stream);
+
+			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_RECVONLY);
+		} while (--n);
+	}
+
+	return res;
+}
+
+static int stream_echo_exec(struct ast_channel *chan, const char *data)
+{
+	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;
+}
+
+static int unload_module(void)
+{
+	return ast_unregister_application(app);
+}
+
+static int load_module(void)
+{
+	return ast_register_application_xml(app, stream_echo_exec);
+}
+
+AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Stream Echo Application");