1 files changed, 404 insertions, 0 deletions
diff --git a/bridges/bridge_multiplexed.c b/bridges/bridge_multiplexed.c
new file mode 100644
index 000000000..520673134
--- /dev/null
+++ b/bridges/bridge_multiplexed.c
@@ -0,0 +1,404 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 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
+ *
+ * \brief Two channel bridging module which groups bridges into batches of threads
+ *
+ * \author Joshua Colp <jcolp@digium.com>
+ *
+ * \ingroup bridges
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "asterisk/module.h"
+#include "asterisk/channel.h"
+#include "asterisk/bridging.h"
+#include "asterisk/bridging_technology.h"
+#include "asterisk/frame.h"
+#include "asterisk/astobj2.h"
+
+/*! \brief Number of buckets our multiplexed thread container can have */
+#define MULTIPLEXED_BUCKETS 53
+
+/*! \brief Number of channels we handle in a single thread */
+#define MULTIPLEXED_MAX_CHANNELS 8
+
+/*! \brief Structure which represents a single thread handling multiple 2 channel bridges */
+struct multiplexed_thread {
+	/*! Thread itself */
+	pthread_t thread;
+	/*! Pipe used to wake up the multiplexed thread */
+	int pipe[2];
+	/*! Channels in this thread */
+	struct ast_channel *chans[MULTIPLEXED_MAX_CHANNELS];
+	/*! Number of channels in this thread */
+	unsigned int count;
+	/*! Bit used to indicate that the thread is waiting on channels */
+	unsigned int waiting:1;
+	/*! Number of channels actually being serviced by this thread */
+	unsigned int service_count;
+};
+
+/*! \brief Container of all operating multiplexed threads */
+static struct ao2_container *multiplexed_threads;
+
+/*! \brief Callback function for finding a free multiplexed thread */
+static int find_multiplexed_thread(void *obj, void *arg, int flags)
+{
+	struct multiplexed_thread *multiplexed_thread = obj;
+	return (multiplexed_thread->count <= (MULTIPLEXED_MAX_CHANNELS - 2)) ? CMP_MATCH | CMP_STOP : 0;
+}
+
+/*! \brief Destroy callback for a multiplexed thread structure */
+static void destroy_multiplexed_thread(void *obj)
+{
+	struct multiplexed_thread *multiplexed_thread = obj;
+
+	if (multiplexed_thread->pipe[0] > -1) {
+		close(multiplexed_thread->pipe[0]);
+	}
+	if (multiplexed_thread->pipe[1] > -1) {
+		close(multiplexed_thread->pipe[1]);
+	}
+
+	return;
+}
+
+/*! \brief Create function which finds/reserves/references a multiplexed thread structure */
+static int multiplexed_bridge_create(struct ast_bridge *bridge)
+{
+	struct multiplexed_thread *multiplexed_thread;
+
+	ao2_lock(multiplexed_threads);
+
+	/* Try to find an existing thread to handle our additional channels */
+	if (!(multiplexed_thread = ao2_callback(multiplexed_threads, 0, find_multiplexed_thread, NULL))) {
+		int flags;
+
+		/* If we failed we will have to create a new one from scratch */
+		if (!(multiplexed_thread = ao2_alloc(sizeof(*multiplexed_thread), destroy_multiplexed_thread))) {
+			ast_debug(1, "Failed to find or create a new multiplexed thread for bridge '%p'\n", bridge);
+			ao2_unlock(multiplexed_threads);
+			return -1;
+		}
+
+		multiplexed_thread->pipe[0] = multiplexed_thread->pipe[1] = -1;
+		/* Setup a pipe so we can poke the thread itself when needed */
+		if (pipe(multiplexed_thread->pipe)) {
+			ast_debug(1, "Failed to create a pipe for poking a multiplexed thread for bridge '%p'\n", bridge);
+			ao2_ref(multiplexed_thread, -1);
+			ao2_unlock(multiplexed_threads);
+			return -1;
+		}
+
+		/* Setup each pipe for non-blocking operation */
+		flags = fcntl(multiplexed_thread->pipe[0], F_GETFL);
+		if (fcntl(multiplexed_thread->pipe[0], F_SETFL, flags | O_NONBLOCK) < 0) {
+			ast_log(LOG_WARNING, "Failed to setup first nudge pipe for non-blocking operation on %p (%d: %s)\n", bridge, errno, strerror(errno));
+			ao2_ref(multiplexed_thread, -1);
+			ao2_unlock(multiplexed_threads);
+			return -1;
+		}
+		flags = fcntl(multiplexed_thread->pipe[1], F_GETFL);
+		if (fcntl(multiplexed_thread->pipe[1], F_SETFL, flags | O_NONBLOCK) < 0) {
+			ast_log(LOG_WARNING, "Failed to setup second nudge pipe for non-blocking operation on %p (%d: %s)\n", bridge, errno, strerror(errno));
+			ao2_ref(multiplexed_thread, -1);
+			ao2_unlock(multiplexed_threads);
+			return -1;
+		}
+
+		/* Set up default parameters */
+		multiplexed_thread->thread = AST_PTHREADT_NULL;
+
+		/* Finally link us into the container so others may find us */
+		ao2_link(multiplexed_threads, multiplexed_thread);
+		ast_debug(1, "Created multiplexed thread '%p' for bridge '%p'\n", multiplexed_thread, bridge);
+	} else {
+		ast_debug(1, "Found multiplexed thread '%p' for bridge '%p'\n", multiplexed_thread, bridge);
+	}
+
+	/* Bump the count of the thread structure up by two since the channels for this bridge will be joining shortly */
+	multiplexed_thread->count += 2;
+
+	ao2_unlock(multiplexed_threads);
+
+	bridge->bridge_pvt = multiplexed_thread;
+
+	return 0;
+}
+
+/*! \brief Internal function which nudges the thread */
+static void multiplexed_nudge(struct multiplexed_thread *multiplexed_thread)
+{
+	int nudge = 0;
+
+	if (multiplexed_thread->thread == AST_PTHREADT_NULL) {
+		return;
+	}
+
+	if (write(multiplexed_thread->pipe[1], &nudge, sizeof(nudge)) != sizeof(nudge)) {
+		ast_log(LOG_ERROR, "We couldn't poke multiplexed thread '%p'... something is VERY wrong\n", multiplexed_thread);
+	}
+
+	while (multiplexed_thread->waiting) {
+		sched_yield();
+	}
+
+	return;
+}
+
+/*! \brief Destroy function which unreserves/unreferences/removes a multiplexed thread structure */
+static int multiplexed_bridge_destroy(struct ast_bridge *bridge)
+{
+	struct multiplexed_thread *multiplexed_thread = bridge->bridge_pvt;
+
+	ao2_lock(multiplexed_threads);
+
+	multiplexed_thread->count -= 2;
+
+	if (!multiplexed_thread->count) {
+		ast_debug(1, "Unlinking multiplexed thread '%p' since nobody is using it anymore\n", multiplexed_thread);
+		ao2_unlink(multiplexed_threads, multiplexed_thread);
+	}
+
+	multiplexed_nudge(multiplexed_thread);
+
+	ao2_unlock(multiplexed_threads);
+
+	ao2_ref(multiplexed_thread, -1);
+
+	return 0;
+}
+
+/*! \brief Thread function that executes for multiplexed threads */
+static void *multiplexed_thread_function(void *data)
+{
+	struct multiplexed_thread *multiplexed_thread = data;
+	int fds = multiplexed_thread->pipe[0];
+
+	ao2_lock(multiplexed_thread);
+
+	ast_debug(1, "Starting actual thread for multiplexed thread '%p'\n", multiplexed_thread);
+
+	while (multiplexed_thread->thread != AST_PTHREADT_STOP) {
+		struct ast_channel *winner = NULL, *first = multiplexed_thread->chans[0];
+		int to = -1, outfd = -1;
+
+		/* Move channels around so not just the first one gets priority */
+		memmove(multiplexed_thread->chans, multiplexed_thread->chans + 1, sizeof(struct ast_channel *) * (multiplexed_thread->service_count - 1));
+		multiplexed_thread->chans[multiplexed_thread->service_count - 1] = first;
+
+		multiplexed_thread->waiting = 1;
+		ao2_unlock(multiplexed_thread);
+		winner = ast_waitfor_nandfds(multiplexed_thread->chans, multiplexed_thread->service_count, &fds, 1, NULL, &outfd, &to);
+		multiplexed_thread->waiting = 0;
+		ao2_lock(multiplexed_thread);
+
+		if (outfd > -1) {
+			int nudge;
+
+			if (read(multiplexed_thread->pipe[0], &nudge, sizeof(nudge)) < 0) {
+				if (errno != EINTR && errno != EAGAIN) {
+					ast_log(LOG_WARNING, "read() failed for pipe on multiplexed thread '%p': %s\n", multiplexed_thread, strerror(errno));
+				}
+			}
+		}
+		if (winner && winner->bridge) {
+			ast_bridge_handle_trip(winner->bridge, NULL, winner, -1);
+		}
+	}
+
+	multiplexed_thread->thread = AST_PTHREADT_NULL;
+
+	ast_debug(1, "Stopping actual thread for multiplexed thread '%p'\n", multiplexed_thread);
+
+	ao2_unlock(multiplexed_thread);
+	ao2_ref(multiplexed_thread, -1);
+
+	return NULL;
+}
+
+/*! \brief Helper function which adds or removes a channel and nudges the thread */
+static void multiplexed_add_or_remove(struct multiplexed_thread *multiplexed_thread, struct ast_channel *chan, int add)
+{
+	int i, removed = 0;
+	pthread_t thread = AST_PTHREADT_NULL;
+
+	ao2_lock(multiplexed_thread);
+
+	multiplexed_nudge(multiplexed_thread);
+
+	for (i = 0; i < MULTIPLEXED_MAX_CHANNELS; i++) {
+		if (multiplexed_thread->chans[i] == chan) {
+			if (!add) {
+				multiplexed_thread->chans[i] = NULL;
+				multiplexed_thread->service_count--;
+				removed = 1;
+			}
+			break;
+		} else if (!multiplexed_thread->chans[i] && add) {
+			multiplexed_thread->chans[i] = chan;
+			multiplexed_thread->service_count++;
+			break;
+		}
+	}
+
+	if (multiplexed_thread->service_count && multiplexed_thread->thread == AST_PTHREADT_NULL) {
+		ao2_ref(multiplexed_thread, +1);
+		if (ast_pthread_create(&multiplexed_thread->thread, NULL, multiplexed_thread_function, multiplexed_thread)) {
+			ao2_ref(multiplexed_thread, -1);
+			ast_debug(1, "Failed to create an actual thread for multiplexed thread '%p', trying next time\n", multiplexed_thread);
+		}
+	} else if (!multiplexed_thread->service_count && multiplexed_thread->thread != AST_PTHREADT_NULL) {
+		thread = multiplexed_thread->thread;
+		multiplexed_thread->thread = AST_PTHREADT_STOP;
+	} else if (!add && removed) {
+		memmove(multiplexed_thread->chans + i, multiplexed_thread->chans + i + 1, sizeof(struct ast_channel *) * (MULTIPLEXED_MAX_CHANNELS - (i + 1)));
+	}
+
+	ao2_unlock(multiplexed_thread);
+
+	if (thread != AST_PTHREADT_NULL) {
+		pthread_join(thread, NULL);
+	}
+
+	return;
+}
+
+/*! \brief Join function which actually adds the channel into the array to be monitored */
+static int multiplexed_bridge_join(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
+{
+	struct ast_channel *c0 = AST_LIST_FIRST(&bridge->channels)->chan, *c1 = AST_LIST_LAST(&bridge->channels)->chan;
+	struct multiplexed_thread *multiplexed_thread = bridge->bridge_pvt;
+
+	ast_debug(1, "Adding channel '%s' to multiplexed thread '%p' for monitoring\n", bridge_channel->chan->name, multiplexed_thread);
+
+	multiplexed_add_or_remove(multiplexed_thread, bridge_channel->chan, 1);
+
+	/* If the second channel has not yet joined do not make things compatible */
+	if (c0 == c1) {
+		return 0;
+	}
+
+	if (((c0->writeformat == c1->readformat) && (c0->readformat == c1->writeformat) && (c0->nativeformats == c1->nativeformats))) {
+		return 0;
+	}
+
+	return ast_channel_make_compatible(c0, c1);
+}
+
+/*! \brief Leave function which actually removes the channel from the array */
+static int multiplexed_bridge_leave(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
+{
+	struct multiplexed_thread *multiplexed_thread = bridge->bridge_pvt;
+
+	ast_debug(1, "Removing channel '%s' from multiplexed thread '%p'\n", bridge_channel->chan->name, multiplexed_thread);
+
+	multiplexed_add_or_remove(multiplexed_thread, bridge_channel->chan, 0);
+
+	return 0;
+}
+
+/*! \brief Suspend function which means control of the channel is going elsewhere */
+static void multiplexed_bridge_suspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
+{
+	struct multiplexed_thread *multiplexed_thread = bridge->bridge_pvt;
+
+	ast_debug(1, "Suspending channel '%s' from multiplexed thread '%p'\n", bridge_channel->chan->name, multiplexed_thread);
+
+	multiplexed_add_or_remove(multiplexed_thread, bridge_channel->chan, 0);
+
+	return;
+}
+
+/*! \brief Unsuspend function which means control of the channel is coming back to us */
+static void multiplexed_bridge_unsuspend(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel)
+{
+	struct multiplexed_thread *multiplexed_thread = bridge->bridge_pvt;
+
+	ast_debug(1, "Unsuspending channel '%s' from multiplexed thread '%p'\n", bridge_channel->chan->name, multiplexed_thread);
+
+	multiplexed_add_or_remove(multiplexed_thread, bridge_channel->chan, 1);
+
+	return;
+}
+
+/*! \brief Write function for writing frames into the bridge */
+static enum ast_bridge_write_result multiplexed_bridge_write(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_frame *frame)
+{
+	struct ast_bridge_channel *other;
+
+	if (AST_LIST_FIRST(&bridge->channels) == AST_LIST_LAST(&bridge->channels)) {
+		return AST_BRIDGE_WRITE_FAILED;
+	}
+
+	if (!(other = (AST_LIST_FIRST(&bridge->channels) == bridge_channel ? AST_LIST_LAST(&bridge->channels) : AST_LIST_FIRST(&bridge->channels)))) {
+		return AST_BRIDGE_WRITE_FAILED;
+	}
+
+	if (other->state == AST_BRIDGE_CHANNEL_STATE_WAIT) {
+		ast_write(other->chan, frame);
+	}
+
+	return AST_BRIDGE_WRITE_SUCCESS;
+}
+
+static struct ast_bridge_technology multiplexed_bridge = {
+	.name = "multiplexed_bridge",
+	.capabilities = AST_BRIDGE_CAPABILITY_1TO1MIX,
+	.preference = AST_BRIDGE_PREFERENCE_HIGH,
+	.formats = AST_FORMAT_AUDIO_MASK | AST_FORMAT_VIDEO_MASK | AST_FORMAT_TEXT_MASK,
+	.create = multiplexed_bridge_create,
+	.destroy = multiplexed_bridge_destroy,
+	.join = multiplexed_bridge_join,
+	.leave = multiplexed_bridge_leave,
+	.suspend = multiplexed_bridge_suspend,
+	.unsuspend = multiplexed_bridge_unsuspend,
+	.write = multiplexed_bridge_write,
+};
+
+static int unload_module(void)
+{
+	int res = ast_bridge_technology_unregister(&multiplexed_bridge);
+
+	ao2_ref(multiplexed_threads, -1);
+
+	return res;
+}
+
+static int load_module(void)
+{
+	if (!(multiplexed_threads = ao2_container_alloc(MULTIPLEXED_BUCKETS, NULL, NULL))) {
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	return ast_bridge_technology_register(&multiplexed_bridge);
+}
+
+AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Multiplexed two channel bridging module");