Merge phase 1 support for the new bridging architecture.

This commit brings in the bridging core, bridging technologies,
and the ConfBridge application.

For usage information on the ConfBridge application please see
the output of "core show application ConfBridge" from the CLI.

For API documentation please see the doxygen page describing the
architecture and the documentation for each API call.

Review: http://reviewboard.digium.com/r/93/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@180369 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 246 insertions, 0 deletions

diff --git a/channels/chan_bridge.c b/channels/chan_bridge.c
new file mode 100644
index 000000000..84909e795
--- /dev/null
+++ b/channels/chan_bridge.c
@@ -0,0 +1,246 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 1999 - 2008, 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
+ *
+ * \author Joshua Colp <jcolp@digium.com>
+ *
+ * \brief Bridge Interaction Channel
+ *
+ * \ingroup channel_drivers
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include <fcntl.h>
+#include <sys/signal.h>
+
+#include "asterisk/lock.h"
+#include "asterisk/channel.h"
+#include "asterisk/config.h"
+#include "asterisk/module.h"
+#include "asterisk/pbx.h"
+#include "asterisk/sched.h"
+#include "asterisk/io.h"
+#include "asterisk/rtp.h"
+#include "asterisk/acl.h"
+#include "asterisk/callerid.h"
+#include "asterisk/file.h"
+#include "asterisk/cli.h"
+#include "asterisk/app.h"
+#include "asterisk/bridging.h"
+
+static struct ast_channel *bridge_request(const char *type, int format, void *data, int *cause);
+static int bridge_call(struct ast_channel *ast, char *dest, int timeout);
+static int bridge_hangup(struct ast_channel *ast);
+static struct ast_frame *bridge_read(struct ast_channel *ast);
+static int bridge_write(struct ast_channel *ast, struct ast_frame *f);
+static struct ast_channel *bridge_bridgedchannel(struct ast_channel *chan, struct ast_channel *bridge);
+
+static const struct ast_channel_tech bridge_tech = {
+	.type = "Bridge",
+	.description = "Bridge Interaction Channel",
+	.capabilities = -1,
+	.requester = bridge_request,
+	.call = bridge_call,
+	.hangup = bridge_hangup,
+	.read = bridge_read,
+	.write = bridge_write,
+	.write_video = bridge_write,
+	.exception = bridge_read,
+	.bridged_channel = bridge_bridgedchannel,
+};
+
+struct bridge_pvt {
+	ast_mutex_t lock;           /*!< Lock that protects this structure */
+	struct ast_channel *input;  /*!< Input channel - talking to source */
+	struct ast_channel *output; /*!< Output channel - talking to bridge */
+};
+
+/*! \brief Called when the user of this channel wants to get the actual channel in the bridge */
+static struct ast_channel *bridge_bridgedchannel(struct ast_channel *chan, struct ast_channel *bridge)
+{
+	struct bridge_pvt *p = chan->tech_pvt;
+	return (chan == p->input) ? p->output : bridge;
+}
+
+/*! \brief Called when a frame should be read from the channel */
+static struct ast_frame  *bridge_read(struct ast_channel *ast)
+{
+	return &ast_null_frame;
+}
+
+/*! \brief Called when a frame should be written out to a channel */
+static int bridge_write(struct ast_channel *ast, struct ast_frame *f)
+{
+	struct bridge_pvt *p = ast->tech_pvt;
+	struct ast_channel *other;
+
+	ast_mutex_lock(&p->lock);
+
+	other = (p->input == ast ? p->output : p->input);
+
+	while (other && ast_channel_trylock(other)) {
+		ast_mutex_unlock(&p->lock);
+		do {
+			CHANNEL_DEADLOCK_AVOIDANCE(ast);
+		} while (ast_mutex_trylock(&p->lock));
+		other = (p->input == ast ? p->output : p->input);
+	}
+
+	/* We basically queue the frame up on the other channel if present */
+	if (other) {
+		ast_queue_frame(other, f);
+		ast_channel_unlock(other);
+	}
+
+	ast_mutex_unlock(&p->lock);
+
+	return 0;
+}
+
+/*! \brief Called when the channel should actually be dialed */
+static int bridge_call(struct ast_channel *ast, char *dest, int timeout)
+{
+	struct bridge_pvt *p = ast->tech_pvt;
+
+	/* If no bridge has been provided on the input channel, bail out */
+	if (!ast->bridge) {
+		return -1;
+	}
+
+	/* Impart the output channel upon the given bridge of the input channel */
+	ast_bridge_impart(p->input->bridge, p->output, NULL, NULL);
+
+	return 0;
+}
+
+/*! \brief Helper function to not deadlock when queueing the hangup frame */
+static void bridge_queue_hangup(struct bridge_pvt *p, struct ast_channel *us)
+{
+	struct ast_channel *other = (p->input == us ? p->output : p->input);
+
+	while (other && ast_channel_trylock(other)) {
+		ast_mutex_unlock(&p->lock);
+		do {
+			CHANNEL_DEADLOCK_AVOIDANCE(us);
+		} while (ast_mutex_trylock(&p->lock));
+		other = (p->input == us ? p->output : p->input);
+	}
+
+	/* We basically queue the frame up on the other channel if present */
+	if (other) {
+		ast_queue_hangup(other);
+		ast_channel_unlock(other);
+	}
+
+	return;
+}
+
+/*! \brief Called when a channel should be hung up */
+static int bridge_hangup(struct ast_channel *ast)
+{
+	struct bridge_pvt *p = ast->tech_pvt;
+
+	ast_mutex_lock(&p->lock);
+
+	/* Figure out which channel this is... and set it to NULL as it has gone, but also queue up a hangup frame. */
+	if (p->input == ast) {
+		if (p->output) {
+			bridge_queue_hangup(p, ast);
+		}
+		p->input = NULL;
+	} else if (p->output == ast) {
+		if (p->input) {
+			bridge_queue_hangup(p, ast);
+		}
+		p->output = NULL;
+	}
+
+	/* Deal with the Asterisk portion of it */
+	ast->tech_pvt = NULL;
+
+	/* If both sides have been terminated free the structure and be done with things */
+	if (!p->input && !p->output) {
+		ast_mutex_unlock(&p->lock);
+		ast_mutex_destroy(&p->lock);
+		ast_free(p);
+	} else {
+		ast_mutex_unlock(&p->lock);
+	}
+
+	return 0;
+}
+
+/*! \brief Called when we want to place a call somewhere, but not actually call it... yet */
+static struct ast_channel *bridge_request(const char *type, int format, void *data, int *cause)
+{
+	struct bridge_pvt *p = NULL;
+
+	/* Try to allocate memory for our very minimal pvt structure */
+	if (!(p = ast_calloc(1, sizeof(*p)))) {
+		return NULL;
+	}
+
+	/* Try to grab two Asterisk channels to use as input and output channels */
+	if (!(p->input = ast_channel_alloc(1, AST_STATE_UP, 0, 0, "", "", "", 0, "Bridge/%p-input", p))) {
+		ast_free(p);
+		return NULL;
+	}
+	if (!(p->output = ast_channel_alloc(1, AST_STATE_UP, 0, 0, "", "", "", 0, "Bridge/%p-output", p))) {
+		ast_channel_free(p->input);
+		ast_free(p);
+		return NULL;
+	}
+
+	/* Setup the lock on the pvt structure, we will need that */
+	ast_mutex_init(&p->lock);
+
+	/* Setup parameters on both new channels */
+	p->input->tech = p->output->tech = &bridge_tech;
+	p->input->tech_pvt = p->output->tech_pvt = p;
+	p->input->nativeformats = p->output->nativeformats = AST_FORMAT_SLINEAR;
+	p->input->readformat = p->output->readformat = AST_FORMAT_SLINEAR;
+	p->input->rawreadformat = p->output->rawreadformat = AST_FORMAT_SLINEAR;
+	p->input->writeformat = p->output->writeformat = AST_FORMAT_SLINEAR;
+	p->input->rawwriteformat = p->output->rawwriteformat = AST_FORMAT_SLINEAR;
+
+	return p->input;
+}
+
+/*! \brief Load module into PBX, register channel */
+static int load_module(void)
+{
+	/* Make sure we can register our channel type */
+	if (ast_channel_register(&bridge_tech)) {
+		ast_log(LOG_ERROR, "Unable to register channel class 'Bridge'\n");
+		return AST_MODULE_LOAD_FAILURE;
+	}
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+/*! \brief Unload the bridge interaction channel from Asterisk */
+static int unload_module(void)
+{
+	ast_channel_unregister(&bridge_tech);
+	return 0;
+}
+
+AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Bridge Interaction Channel");