Thu Sep 7 01:02:54 2017

Asterisk developer's documentation


bridge_simple.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 2007, Digium, Inc.
00005  *
00006  * Joshua Colp <jcolp@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  *
00021  * \brief Simple two channel bridging module
00022  *
00023  * \author Joshua Colp <jcolp@digium.com>
00024  *
00025  * \ingroup bridges
00026  */
00027 
00028 /*** MODULEINFO
00029    <support_level>core</support_level>
00030  ***/
00031 
00032 #include "asterisk.h"
00033 
00034 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 328209 $")
00035 
00036 #include <stdio.h>
00037 #include <stdlib.h>
00038 #include <string.h>
00039 #include <sys/types.h>
00040 #include <sys/stat.h>
00041 
00042 #include "asterisk/module.h"
00043 #include "asterisk/channel.h"
00044 #include "asterisk/bridging.h"
00045 #include "asterisk/bridging_technology.h"
00046 #include "asterisk/frame.h"
00047 
00048 static int simple_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
00049 {
00050    struct ast_channel *c0 = AST_LIST_FIRST(&bridge->channels)->chan, *c1 = AST_LIST_LAST(&bridge->channels)->chan;
00051 
00052    /* If this is the first channel we can't make it compatible... unless we make it compatible with itself O.o */
00053    if (AST_LIST_FIRST(&bridge->channels) == AST_LIST_LAST(&bridge->channels)) {
00054       return 0;
00055    }
00056 
00057    /* See if we need to make these compatible */
00058    if (((c0->writeformat == c1->readformat) && (c0->readformat == c1->writeformat) && (c0->nativeformats == c1->nativeformats))) {
00059       return 0;
00060    }
00061 
00062    /* BOOM! We do. */
00063    return ast_channel_make_compatible(c0, c1);
00064 }
00065 
00066 static enum ast_bridge_write_result simple_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
00067 {
00068    struct ast_bridge_channel *other = NULL;
00069 
00070    /* If this is the only channel in this bridge then immediately exit */
00071    if (AST_LIST_FIRST(&bridge->channels) == AST_LIST_LAST(&bridge->channels)) {
00072       return AST_BRIDGE_WRITE_FAILED;
00073    }
00074 
00075    /* Find the channel we actually want to write to */
00076    if (!(other = (AST_LIST_FIRST(&bridge->channels) == bridge_channel ? AST_LIST_LAST(&bridge->channels) : AST_LIST_FIRST(&bridge->channels)))) {
00077       return AST_BRIDGE_WRITE_FAILED;
00078    }
00079 
00080    /* Write the frame out if they are in the waiting state... don't worry about freeing it, the bridging core will take care of it */
00081    if (other->state == AST_BRIDGE_CHANNEL_STATE_WAIT) {
00082       ast_write(other->chan, frame);
00083    }
00084 
00085    return AST_BRIDGE_WRITE_SUCCESS;
00086 }
00087 
00088 static struct ast_bridge_technology simple_bridge = {
00089    .name = "simple_bridge",
00090    .capabilities = AST_BRIDGE_CAPABILITY_1TO1MIX | AST_BRIDGE_CAPABILITY_THREAD,
00091    .preference = AST_BRIDGE_PREFERENCE_MEDIUM,
00092    .formats = AST_FORMAT_AUDIO_MASK | AST_FORMAT_VIDEO_MASK | AST_FORMAT_TEXT_MASK,
00093    .join = simple_bridge_join,
00094    .write = simple_bridge_write,
00095 };
00096 
00097 static int unload_module(void)
00098 {
00099    return ast_bridge_technology_unregister(&simple_bridge);
00100 }
00101 
00102 static int load_module(void)
00103 {
00104    return ast_bridge_technology_register(&simple_bridge);
00105 }
00106 
00107 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Simple two channel bridging module");

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