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");