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
This commit is contained in:
Joshua Colp
parent
e313ec3a7e
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2f38bcdfc0
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/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2018, Digium, Inc.
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*
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* Joshua Colp <jcolp@digium.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*!
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* \file
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*
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* \brief REMB Modifier Module
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*
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* \author Joshua Colp <jcolp@digium.com>
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*/
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/*** MODULEINFO
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<support_level>extended</support_level>
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<defaultenabled>no</defaultenabled>
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***/
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#include "asterisk.h"
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#include "asterisk/module.h"
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#include "asterisk/cli.h"
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#include "asterisk/channel.h"
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#include "asterisk/framehook.h"
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#include "asterisk/rtp_engine.h"
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struct remb_values {
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/*! \brief The amount of bitrate to use for REMB received from the channel */
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unsigned int receive_bitrate;
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/*! \brief The amount of bitrate to use for REMB sent to the channel */
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unsigned int send_bitrate;
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};
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static void remb_values_free(void *data)
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{
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ast_free(data);
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}
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static const struct ast_datastore_info remb_info = {
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.type = "REMB Values",
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.destroy = remb_values_free,
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};
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static struct ast_frame *remb_hook_event_cb(struct ast_channel *chan, struct ast_frame *frame, enum ast_framehook_event event, void *data)
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{
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struct ast_rtp_rtcp_feedback *feedback;
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struct ast_datastore *remb_store;
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struct remb_values *remb_values;
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if (!frame) {
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return NULL;
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}
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switch (event) {
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case AST_FRAMEHOOK_EVENT_READ:
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case AST_FRAMEHOOK_EVENT_WRITE:
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break;
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case AST_FRAMEHOOK_EVENT_ATTACHED:
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case AST_FRAMEHOOK_EVENT_DETACHED:
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return frame;
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}
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/* We only care about REMB frames, all others will be unmodified */
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if (frame->subclass.integer != AST_RTP_RTCP_PSFB) {
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return frame;
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}
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feedback = frame->data.ptr;
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if (feedback->fmt != AST_RTP_RTCP_FMT_REMB) {
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return frame;
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}
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remb_store = ast_channel_datastore_find(chan, &remb_info, NULL);
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if (!remb_store) {
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return frame;
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}
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remb_values = remb_store->data;
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/* If a bitrate override has been set apply it to the REMB Frame */
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if (event == AST_FRAMEHOOK_EVENT_READ && remb_values->receive_bitrate) {
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feedback->remb.br_mantissa = remb_values->receive_bitrate;
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feedback->remb.br_exp = 0;
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} else if (event == AST_FRAMEHOOK_EVENT_WRITE && remb_values->send_bitrate) {
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feedback->remb.br_mantissa = remb_values->send_bitrate;
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feedback->remb.br_exp = 0;
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}
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/* The mantissa only has 18 bits available, so while it exceeds them we bump
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* up the exp.
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*/
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while (feedback->remb.br_mantissa > 0x3ffff) {
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feedback->remb.br_mantissa = feedback->remb.br_mantissa >> 1;
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feedback->remb.br_exp++;
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}
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return frame;
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}
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static char *handle_remb_set(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
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{
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struct ast_channel *chan;
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unsigned int bitrate;
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struct ast_datastore *remb_store;
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struct remb_values *remb_values;
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struct ast_framehook_interface interface = {
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.version = AST_FRAMEHOOK_INTERFACE_VERSION,
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.event_cb = remb_hook_event_cb,
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};
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switch(cmd) {
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case CLI_INIT:
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e->command = "remb set {send|receive}";
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e->usage =
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"Usage: remb set {send|receive} <channel> <bitrate in bits>\n"
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" Set the REMB value which overwrites what we send or receive\n";
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return NULL;
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case CLI_GENERATE:
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return ast_complete_channels(a->line, a->word, a->pos, a->n, 3);
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}
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if (a->argc != 5) {
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return CLI_SHOWUSAGE;
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}
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if (sscanf(a->argv[4], "%30d", &bitrate) != 1) {
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ast_cli(a->fd, "%s is not a valid bitrate in bits\n", a->argv[4]);
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return CLI_SUCCESS;
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} else if (strcasecmp(a->argv[2], "send") && strcasecmp(a->argv[2], "receive")) {
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ast_cli(a->fd, "%s is not a valid direction for REMB\n", a->argv[2]);
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return CLI_SUCCESS;
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}
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chan = ast_channel_get_by_name(a->argv[3]);
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if (!chan) {
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ast_cli(a->fd, "%s is not a known channel\n", a->argv[3]);
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return CLI_SUCCESS;
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}
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ast_channel_lock(chan);
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remb_store = ast_channel_datastore_find(chan, &remb_info, NULL);
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if (!remb_store) {
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int framehook_id;
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framehook_id = ast_framehook_attach(chan, &interface);
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if (framehook_id < 0) {
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ast_cli(a->fd, "Could not attach framehook for modifying REMB\n");
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ast_channel_unlock(chan);
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ast_channel_unref(chan);
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return CLI_SUCCESS;
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}
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remb_values = ast_calloc(1, sizeof(*remb_values));
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if (!remb_values) {
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ast_cli(a->fd, "Could not create a place to store provided REMB value\n");
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ast_framehook_detach(chan, framehook_id);
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ast_channel_unlock(chan);
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ast_channel_unref(chan);
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return CLI_SUCCESS;
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}
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remb_store = ast_datastore_alloc(&remb_info, NULL);
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if (!remb_store) {
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ast_cli(a->fd, "Could not create a place to store provided REMB value\n");
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ast_framehook_detach(chan, framehook_id);
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ast_channel_unlock(chan);
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ast_channel_unref(chan);
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ast_free(remb_values);
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return CLI_SUCCESS;
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}
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remb_store->data = remb_values;
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ast_channel_datastore_add(chan, remb_store);
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} else {
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remb_values = remb_store->data;
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}
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if (!strcasecmp(a->argv[2], "send")) {
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remb_values->send_bitrate = bitrate;
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} else if (!strcasecmp(a->argv[2], "receive")) {
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remb_values->receive_bitrate = bitrate;
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}
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ast_channel_unlock(chan);
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ast_channel_unref(chan);
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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]);
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return CLI_SUCCESS;
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}
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static struct ast_cli_entry remb_cli[] = {
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AST_CLI_DEFINE(handle_remb_set, "Set the REMB value which overwrites what is sent or received"),
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};
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static int load_module(void)
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{
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ast_cli_register_multiple(remb_cli, ARRAY_LEN(remb_cli));
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return AST_MODULE_LOAD_SUCCESS;
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}
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static int unload_module(void)
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{
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ast_cli_unregister_multiple(remb_cli, ARRAY_LEN(remb_cli));
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return 0;
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}
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AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "REMB Modifier Module",
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.support_level = AST_MODULE_SUPPORT_EXTENDED,
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.load = load_module,
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.unload = unload_module,
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);
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