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	res_remb_modifier: Add module for controlling REMB from CLI.
This adds a module which registers a CLI command that can set the REMB bitrate value for REMB as it enters or exits Asterisk. This allows you to ignore what Asterisk or a client produces and is useful for demonstrations. This does not generate REMB frames, however, but just modifies them as they flow to or from a channel. Change-Id: Ib089427c46a4a36d645cecfe02406adb38c17bec
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							| @@ -0,0 +1,225 @@ | ||||
| /* | ||||
|  * Asterisk -- An open source telephony toolkit. | ||||
|  * | ||||
|  * Copyright (C) 2018, Digium, Inc. | ||||
|  * | ||||
|  * Joshua Colp <jcolp@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 REMB Modifier Module | ||||
|  * | ||||
|  * \author Joshua Colp <jcolp@digium.com> | ||||
|  */ | ||||
|  | ||||
| /*** MODULEINFO | ||||
| 	<support_level>extended</support_level> | ||||
| 	<defaultenabled>no</defaultenabled> | ||||
|  ***/ | ||||
|  | ||||
| #include "asterisk.h" | ||||
|  | ||||
| #include "asterisk/module.h" | ||||
| #include "asterisk/cli.h" | ||||
| #include "asterisk/channel.h" | ||||
| #include "asterisk/framehook.h" | ||||
| #include "asterisk/rtp_engine.h" | ||||
|  | ||||
| struct remb_values { | ||||
| 	/*! \brief The amount of bitrate to use for REMB received from the channel */ | ||||
| 	unsigned int receive_bitrate; | ||||
| 	/*! \brief The amount of bitrate to use for REMB sent to the channel */ | ||||
| 	unsigned int send_bitrate; | ||||
| }; | ||||
|  | ||||
| static void remb_values_free(void *data) | ||||
| { | ||||
| 	ast_free(data); | ||||
| } | ||||
|  | ||||
| static const struct ast_datastore_info remb_info = { | ||||
| 	.type = "REMB Values", | ||||
| 	.destroy = remb_values_free, | ||||
| }; | ||||
|  | ||||
| static struct ast_frame *remb_hook_event_cb(struct ast_channel *chan, struct ast_frame *frame, enum ast_framehook_event event, void *data) | ||||
| { | ||||
| 	struct ast_rtp_rtcp_feedback *feedback; | ||||
| 	struct ast_datastore *remb_store; | ||||
| 	struct remb_values *remb_values; | ||||
|  | ||||
| 	if (!frame) { | ||||
| 		return NULL; | ||||
| 	} | ||||
|  | ||||
| 	switch (event) { | ||||
| 	case AST_FRAMEHOOK_EVENT_READ: | ||||
| 	case AST_FRAMEHOOK_EVENT_WRITE: | ||||
| 		break; | ||||
| 	case AST_FRAMEHOOK_EVENT_ATTACHED: | ||||
| 	case AST_FRAMEHOOK_EVENT_DETACHED: | ||||
| 		return frame; | ||||
| 	} | ||||
|  | ||||
| 	/* We only care about REMB frames, all others will be unmodified */ | ||||
| 	if (frame->subclass.integer != AST_RTP_RTCP_PSFB) { | ||||
| 		return frame; | ||||
| 	} | ||||
|  | ||||
| 	feedback = frame->data.ptr; | ||||
| 	if (feedback->fmt != AST_RTP_RTCP_FMT_REMB) { | ||||
| 		return frame; | ||||
| 	} | ||||
|  | ||||
| 	remb_store = ast_channel_datastore_find(chan, &remb_info, NULL); | ||||
| 	if (!remb_store) { | ||||
| 		return frame; | ||||
| 	} | ||||
| 	remb_values = remb_store->data; | ||||
|  | ||||
| 	/* If a bitrate override has been set apply it to the REMB Frame */ | ||||
| 	if (event == AST_FRAMEHOOK_EVENT_READ && remb_values->receive_bitrate) { | ||||
| 		feedback->remb.br_mantissa = remb_values->receive_bitrate; | ||||
| 		feedback->remb.br_exp = 0; | ||||
| 	} else if (event == AST_FRAMEHOOK_EVENT_WRITE && remb_values->send_bitrate) { | ||||
| 		feedback->remb.br_mantissa = remb_values->send_bitrate; | ||||
| 		feedback->remb.br_exp = 0; | ||||
| 	} | ||||
|  | ||||
| 	/* The mantissa only has 18 bits available, so while it exceeds them we bump | ||||
| 	 * up the exp. | ||||
| 	 */ | ||||
| 	while (feedback->remb.br_mantissa > 0x3ffff) { | ||||
| 		feedback->remb.br_mantissa = feedback->remb.br_mantissa >> 1; | ||||
| 		feedback->remb.br_exp++; | ||||
| 	} | ||||
|  | ||||
| 	return frame; | ||||
| } | ||||
|  | ||||
| static char *handle_remb_set(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a) | ||||
| { | ||||
| 	struct ast_channel *chan; | ||||
| 	unsigned int bitrate; | ||||
| 	struct ast_datastore *remb_store; | ||||
| 	struct remb_values *remb_values; | ||||
| 	struct ast_framehook_interface interface = { | ||||
| 		.version = AST_FRAMEHOOK_INTERFACE_VERSION, | ||||
| 		.event_cb = remb_hook_event_cb, | ||||
| 	}; | ||||
|  | ||||
| 	switch(cmd) { | ||||
| 	case CLI_INIT: | ||||
| 		e->command = "remb set {send|receive}"; | ||||
| 		e->usage = | ||||
| 			"Usage: remb set {send|receive} <channel> <bitrate in bits>\n" | ||||
| 			"       Set the REMB value which overwrites what we send or receive\n"; | ||||
| 		return NULL; | ||||
| 	case CLI_GENERATE: | ||||
| 		return ast_complete_channels(a->line, a->word, a->pos, a->n, 3); | ||||
| 	} | ||||
|  | ||||
| 	if (a->argc != 5) { | ||||
| 		return CLI_SHOWUSAGE; | ||||
| 	} | ||||
|  | ||||
| 	if (sscanf(a->argv[4], "%30d", &bitrate) != 1) { | ||||
| 		ast_cli(a->fd, "%s is not a valid bitrate in bits\n", a->argv[4]); | ||||
| 		return CLI_SUCCESS; | ||||
| 	} else if (strcasecmp(a->argv[2], "send") && strcasecmp(a->argv[2], "receive")) { | ||||
| 		ast_cli(a->fd, "%s is not a valid direction for REMB\n", a->argv[2]); | ||||
| 		return CLI_SUCCESS; | ||||
| 	} | ||||
|  | ||||
| 	chan = ast_channel_get_by_name(a->argv[3]); | ||||
| 	if (!chan) { | ||||
| 		ast_cli(a->fd, "%s is not a known channel\n", a->argv[3]); | ||||
| 		return CLI_SUCCESS; | ||||
| 	} | ||||
|  | ||||
| 	ast_channel_lock(chan); | ||||
|  | ||||
| 	remb_store = ast_channel_datastore_find(chan, &remb_info, NULL); | ||||
| 	if (!remb_store) { | ||||
| 		int framehook_id; | ||||
|  | ||||
| 		framehook_id = ast_framehook_attach(chan, &interface); | ||||
| 		if (framehook_id < 0) { | ||||
| 			ast_cli(a->fd, "Could not attach framehook for modifying REMB\n"); | ||||
| 			ast_channel_unlock(chan); | ||||
| 			ast_channel_unref(chan); | ||||
| 			return CLI_SUCCESS; | ||||
| 		} | ||||
|  | ||||
| 		remb_values = ast_calloc(1, sizeof(*remb_values)); | ||||
| 		if (!remb_values) { | ||||
| 			ast_cli(a->fd, "Could not create a place to store provided REMB value\n"); | ||||
| 			ast_framehook_detach(chan, framehook_id); | ||||
| 			ast_channel_unlock(chan); | ||||
| 			ast_channel_unref(chan); | ||||
| 			return CLI_SUCCESS; | ||||
| 		} | ||||
|  | ||||
| 		remb_store = ast_datastore_alloc(&remb_info, NULL); | ||||
| 		if (!remb_store) { | ||||
| 			ast_cli(a->fd, "Could not create a place to store provided REMB value\n"); | ||||
| 			ast_framehook_detach(chan, framehook_id); | ||||
| 			ast_channel_unlock(chan); | ||||
| 			ast_channel_unref(chan); | ||||
| 			ast_free(remb_values); | ||||
| 			return CLI_SUCCESS; | ||||
| 		} | ||||
|  | ||||
| 		remb_store->data = remb_values; | ||||
| 		ast_channel_datastore_add(chan, remb_store); | ||||
| 	} else { | ||||
| 		remb_values = remb_store->data; | ||||
| 	} | ||||
|  | ||||
| 	if (!strcasecmp(a->argv[2], "send")) { | ||||
| 		remb_values->send_bitrate = bitrate; | ||||
| 	} else if (!strcasecmp(a->argv[2], "receive")) { | ||||
| 		remb_values->receive_bitrate = bitrate; | ||||
| 	} | ||||
|  | ||||
| 	ast_channel_unlock(chan); | ||||
| 	ast_channel_unref(chan); | ||||
|  | ||||
| 	ast_cli(a->fd, "Set REMB %s override to a bitrate of %s on %s\n", a->argv[2], a->argv[3], a->argv[4]); | ||||
|  | ||||
| 	return CLI_SUCCESS; | ||||
| } | ||||
|  | ||||
| static struct ast_cli_entry remb_cli[] = { | ||||
| 	AST_CLI_DEFINE(handle_remb_set, "Set the REMB value which overwrites what is sent or received"), | ||||
| }; | ||||
|  | ||||
| static int load_module(void) | ||||
| { | ||||
| 	ast_cli_register_multiple(remb_cli, ARRAY_LEN(remb_cli)); | ||||
| 	return AST_MODULE_LOAD_SUCCESS; | ||||
| } | ||||
|  | ||||
| static int unload_module(void) | ||||
| { | ||||
| 	ast_cli_unregister_multiple(remb_cli, ARRAY_LEN(remb_cli)); | ||||
| 	return 0; | ||||
| } | ||||
|  | ||||
| AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "REMB Modifier Module", | ||||
| 	.support_level = AST_MODULE_SUPPORT_EXTENDED, | ||||
| 	.load = load_module, | ||||
| 	.unload = unload_module, | ||||
| ); | ||||
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