ari: Add Snoop operation for spying/whispering on channels.

The Snoop operation can be invoked on a channel to spy or
whisper on it. It returns a channel that any channel operations
can then be invoked on (such as record to do monitoring).

(closes issue ASTERISK-22780)
Reported by: Matt Jordan

Review: https://reviewboard.asterisk.org/r/3003/
........

Merged revisions 403117 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@403118 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 394 insertions, 0 deletions

diff --git a/res/res_stasis_snoop.c b/res/res_stasis_snoop.c
new file mode 100644
index 000000000..1a40112d1
--- /dev/null
+++ b/res/res_stasis_snoop.c
@@ -0,0 +1,394 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, 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 Stasis application snoop control support.
+ *
+ * \author Joshua Colp <jcolp@digium.com>
+ */
+
+/*** MODULEINFO
+	<depend type="module">res_stasis</depend>
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/module.h"
+#include "asterisk/stasis_app_impl.h"
+#include "asterisk/stasis_app_snoop.h"
+#include "asterisk/audiohook.h"
+#include "asterisk/pbx.h"
+#include "asterisk/timing.h"
+#include "asterisk/stasis_channels.h"
+#include "asterisk/json.h"
+
+/*! \brief The interval (in milliseconds) that the Snoop timer is triggered, also controls length of audio within frames */
+#define SNOOP_INTERVAL 20
+
+/*! \brief Index used to keep Snoop channel names unique */
+static unsigned int chan_idx;
+
+/*! \brief Structure which contains all of the snoop information */
+struct stasis_app_snoop {
+	/*! \brief Timer used for waking up Stasis thread */
+	struct ast_timer *timer;
+	/*! \brief Audiohook used to spy on the channel */
+	struct ast_audiohook spy;
+	/*! \brief Direction for spying */
+	enum ast_audiohook_direction spy_direction;
+	/*! \brief Number of samples to be read in when spying */
+	unsigned int spy_samples;
+	/*! \brief Format in use by the spy audiohook */
+	struct ast_format spy_format;
+	/*! \brief Audiohook used to whisper on the channel */
+	struct ast_audiohook whisper;
+	/*! \brief Direction for whispering */
+	enum ast_audiohook_direction whisper_direction;
+	/*! \brief Stasis application and arguments */
+	struct ast_str *app;
+	/*! \brief Snoop channel */
+	struct ast_channel *chan;
+	/*! \brief Whether the spy capability is active or not */
+	unsigned int spy_active:1;
+	/*! \brief Whether the whisper capability is active or not */
+	unsigned int whisper_active:1;
+	/*! \brief Uniqueid of the channel this snoop is snooping on */
+	char uniqueid[AST_MAX_UNIQUEID];
+};
+
+/*! \brief Destructor for snoop structure */
+static void snoop_destroy(void *obj)
+{
+	struct stasis_app_snoop *snoop = obj;
+
+	if (snoop->timer) {
+		ast_timer_close(snoop->timer);
+	}
+
+	if (snoop->spy_active) {
+		ast_audiohook_destroy(&snoop->spy);
+	}
+
+	if (snoop->whisper_active) {
+		ast_audiohook_destroy(&snoop->whisper);
+	}
+
+	ast_free(snoop->app);
+
+	ast_channel_cleanup(snoop->chan);
+}
+
+/*! \internal
+ * \brief Publish the chanspy message over Stasis-Core
+ * \param snoop The snoop structure
+ * \start start If non-zero, the spying is starting. Otherwise, the spyer is
+ * finishing
+ */
+static void publish_chanspy_message(struct stasis_app_snoop *snoop, int start)
+{
+	RAII_VAR(struct ast_json *, blob, NULL, ast_json_unref);
+	RAII_VAR(struct ast_multi_channel_blob *, payload, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_message *, message, NULL, ao2_cleanup);
+	RAII_VAR(struct ast_channel_snapshot *, snoop_snapshot, NULL, ao2_cleanup);
+	RAII_VAR(struct ast_channel_snapshot *, spyee_snapshot, NULL, ao2_cleanup);
+
+	blob = ast_json_null();
+	if (!blob) {
+		return;
+	}
+
+	payload = ast_multi_channel_blob_create(blob);
+	if (!payload) {
+		return;
+	}
+
+	snoop_snapshot = ast_channel_snapshot_get_latest(ast_channel_uniqueid(snoop->chan));
+	if (!snoop_snapshot) {
+		return;
+	}
+	ast_multi_channel_blob_add_channel(payload, "spyer_channel", snoop_snapshot);
+
+	spyee_snapshot = ast_channel_snapshot_get_latest(snoop->uniqueid);
+	if (spyee_snapshot) {
+		ast_multi_channel_blob_add_channel(payload, "spyee_channel", spyee_snapshot);
+	}
+
+	message = stasis_message_create(
+			start ? ast_channel_chanspy_start_type(): ast_channel_chanspy_stop_type(),
+					payload);
+	if (!message) {
+		return;
+	}
+
+	stasis_publish(ast_channel_topic(snoop->chan), message);
+}
+
+/*! \brief Callback function for writing to a Snoop whisper audiohook */
+static int snoop_write(struct ast_channel *chan, struct ast_frame *frame)
+{
+	struct stasis_app_snoop *snoop = ast_channel_tech_pvt(chan);
+
+	if (!snoop->whisper_active) {
+		return 0;
+	}
+
+	ast_audiohook_lock(&snoop->whisper);
+	if (snoop->whisper_direction == AST_AUDIOHOOK_DIRECTION_BOTH) {
+		ast_audiohook_write_frame(&snoop->whisper, AST_AUDIOHOOK_DIRECTION_READ, frame);
+		ast_audiohook_write_frame(&snoop->whisper, AST_AUDIOHOOK_DIRECTION_WRITE, frame);
+	} else {
+		ast_audiohook_write_frame(&snoop->whisper, snoop->whisper_direction, frame);
+	}
+	ast_audiohook_unlock(&snoop->whisper);
+
+	return 0;
+}
+
+/*! \brief Callback function for reading from a Snoop channel */
+static struct ast_frame *snoop_read(struct ast_channel *chan)
+{
+	struct stasis_app_snoop *snoop = ast_channel_tech_pvt(chan);
+	struct ast_frame *frame = NULL;
+
+	/* If we fail to ack the timer OR if any active audiohooks are done hangup */
+	if ((ast_timer_ack(snoop->timer, 1) < 0) ||
+		(snoop->spy_active && snoop->spy.status != AST_AUDIOHOOK_STATUS_RUNNING) ||
+		(snoop->whisper_active && snoop->whisper.status != AST_AUDIOHOOK_STATUS_RUNNING)) {
+		return NULL;
+	}
+
+	/* Only get audio from the spy audiohook if it is active */
+	if (snoop->spy_active) {
+		ast_audiohook_lock(&snoop->spy);
+		frame = ast_audiohook_read_frame(&snoop->spy, snoop->spy_samples, snoop->spy_direction, &snoop->spy_format);
+		ast_audiohook_unlock(&snoop->spy);
+	}
+
+	return frame ? frame : &ast_null_frame;
+}
+
+/*! \brief Callback function for hanging up a Snoop channel */
+static int snoop_hangup(struct ast_channel *chan)
+{
+	struct stasis_app_snoop *snoop = ast_channel_tech_pvt(chan);
+
+	if (snoop->spy_active) {
+		ast_audiohook_lock(&snoop->spy);
+		ast_audiohook_detach(&snoop->spy);
+		ast_audiohook_unlock(&snoop->spy);
+	}
+
+	if (snoop->whisper_active) {
+		ast_audiohook_lock(&snoop->whisper);
+		ast_audiohook_detach(&snoop->whisper);
+		ast_audiohook_unlock(&snoop->whisper);
+	}
+
+	publish_chanspy_message(snoop, 0);
+
+	ao2_cleanup(snoop);
+
+	ast_channel_tech_pvt_set(chan, NULL);
+
+	return 0;
+}
+
+static int snoop_fixup(struct ast_channel *oldchan, struct ast_channel *newchan)
+{
+	struct stasis_app_snoop *snoop = ast_channel_tech_pvt(oldchan);
+
+	if (snoop->chan != oldchan) {
+		return -1;
+	}
+
+	ast_channel_unref(snoop->chan);
+	ast_channel_ref(newchan);
+	snoop->chan = newchan;
+
+	return 0;
+}
+
+/*! \brief Channel interface declaration */
+static struct ast_channel_tech snoop_tech = {
+	.type = "Snoop",
+	.description = "Snoop Channel Driver",
+	.write = snoop_write,
+	.read = snoop_read,
+	.hangup = snoop_hangup,
+	.fixup = snoop_fixup,
+};
+
+/*! \brief Thread used for running the Stasis application */
+static void *snoop_stasis_thread(void *obj)
+{
+	RAII_VAR(struct stasis_app_snoop *, snoop, obj, ao2_cleanup);
+	struct ast_app *stasis = pbx_findapp("Stasis");
+
+	if (!stasis) {
+		ast_hangup(snoop->chan);
+		return NULL;
+	}
+
+	pbx_exec(snoop->chan, stasis, ast_str_buffer(snoop->app));
+
+	ast_hangup(snoop->chan);
+
+	return NULL;
+}
+
+/*! \brief Internal helper function which sets up and attaches a snoop audiohook */
+static int snoop_setup_audiohook(struct ast_channel *chan, enum ast_audiohook_type type, enum stasis_app_snoop_direction requested_direction,
+	enum ast_audiohook_direction *direction, struct ast_audiohook *audiohook)
+{
+	ast_audiohook_init(audiohook, type, "Snoop", 0);
+
+	if (requested_direction == STASIS_SNOOP_DIRECTION_OUT) {
+		*direction = AST_AUDIOHOOK_DIRECTION_WRITE;
+	} else if (requested_direction == STASIS_SNOOP_DIRECTION_IN) {
+		*direction = AST_AUDIOHOOK_DIRECTION_READ;
+	} else if (requested_direction == STASIS_SNOOP_DIRECTION_BOTH) {
+		*direction = AST_AUDIOHOOK_DIRECTION_BOTH;
+	} else {
+		return -1;
+	}
+
+	return ast_audiohook_attach(chan, audiohook);
+}
+
+struct ast_channel *stasis_app_control_snoop(struct ast_channel *chan,
+	enum stasis_app_snoop_direction spy, enum stasis_app_snoop_direction whisper,
+	const char *app, const char *app_args)
+{
+	RAII_VAR(struct stasis_app_snoop *, snoop, NULL, ao2_cleanup);
+	unsigned int rate;
+	pthread_t thread;
+
+	if (spy == STASIS_SNOOP_DIRECTION_NONE &&
+		whisper == STASIS_SNOOP_DIRECTION_NONE) {
+		return NULL;
+	}
+
+	snoop = ao2_alloc_options(sizeof(*snoop), snoop_destroy, AO2_ALLOC_OPT_LOCK_NOLOCK);
+	if (!snoop) {
+		return NULL;
+	}
+
+	/* Allocate a buffer to store the Stasis application and arguments in */
+	snoop->app = ast_str_create(64);
+	if (!snoop->app) {
+		return NULL;
+	}
+
+	ast_str_set(&snoop->app, 0, "%s", app);
+	if (!ast_strlen_zero(app_args)) {
+		ast_str_append(&snoop->app, 0, ",%s", app_args);
+	}
+
+	/* Set up a timer for the Snoop channel so it wakes up at a specific interval */
+	snoop->timer = ast_timer_open();
+	if (!snoop->timer) {
+		return NULL;
+	}
+	ast_timer_set_rate(snoop->timer, 1000 / SNOOP_INTERVAL);
+
+	/* Allocate a Snoop channel and set up various parameters */
+	snoop->chan = ast_channel_alloc(1, AST_STATE_UP, "", "", "", "", "", "", 0, "Snoop/%s-%08x", ast_channel_uniqueid(chan),
+		ast_atomic_fetchadd_int((int *)&chan_idx, +1));
+	if (!snoop->chan) {
+		return NULL;
+	}
+
+	strcpy(snoop->uniqueid, ast_channel_uniqueid(chan));
+
+	/* To keep the channel valid on the Snoop structure until it is destroyed we bump the ref up here */
+	ast_channel_ref(snoop->chan);
+
+	ast_channel_tech_set(snoop->chan, &snoop_tech);
+	ao2_ref(snoop, +1);
+	ast_channel_tech_pvt_set(snoop->chan, snoop);
+	ast_channel_set_fd(snoop->chan, 0, ast_timer_fd(snoop->timer));
+
+	{
+		SCOPED_CHANNELLOCK(lock, chan);
+
+		/* Determine the "best" signed linear format capable by the channel we are snooping on */
+		rate = MAX(ast_format_rate(ast_channel_rawwriteformat(chan)), ast_format_rate(ast_channel_rawreadformat(chan)));
+		ast_format_set(&snoop->spy_format, ast_format_slin_by_rate(rate), 0);
+
+		/* The format on the Snoop channel will be this signed linear format, and it will never change */
+		ast_format_cap_set(ast_channel_nativeformats(snoop->chan), &snoop->spy_format);
+		ast_format_copy(ast_channel_writeformat(snoop->chan), &snoop->spy_format);
+		ast_format_copy(ast_channel_rawwriteformat(snoop->chan), &snoop->spy_format);
+		ast_format_copy(ast_channel_readformat(snoop->chan), &snoop->spy_format);
+		ast_format_copy(ast_channel_rawreadformat(snoop->chan), &snoop->spy_format);
+
+		if (spy != STASIS_SNOOP_DIRECTION_NONE) {
+			if (snoop_setup_audiohook(chan, AST_AUDIOHOOK_TYPE_SPY, spy, &snoop->spy_direction, &snoop->spy)) {
+				ast_hangup(snoop->chan);
+				return NULL;
+			}
+
+			snoop->spy_samples = rate / (1000 / SNOOP_INTERVAL);
+			snoop->spy_active = 1;
+		}
+
+		/* If whispering is enabled set up the audiohook */
+		if (whisper != STASIS_SNOOP_DIRECTION_NONE) {
+			if (snoop_setup_audiohook(chan, AST_AUDIOHOOK_TYPE_WHISPER, whisper, &snoop->whisper_direction, &snoop->whisper)) {
+				ast_hangup(snoop->chan);
+				return NULL;
+			}
+
+			snoop->whisper_active = 1;
+		}
+	}
+
+	/* Create the thread which services the Snoop channel */
+	ao2_ref(snoop, +1);
+	if (ast_pthread_create_detached_background(&thread, NULL, snoop_stasis_thread, snoop)) {
+		ao2_cleanup(snoop);
+
+		/* No other thread is servicing this channel so we can immediately hang it up */
+		ast_hangup(snoop->chan);
+		return NULL;
+	}
+
+	publish_chanspy_message(snoop, 1);
+
+	/* The caller of this has a reference as well */
+	return ast_channel_ref(snoop->chan);
+}
+
+static int load_module(void)
+{
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+static int unload_module(void)
+{
+	return 0;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS, "Stasis application snoop support",
+	.load = load_module,
+	.unload = unload_module,
+	.nonoptreq = "res_stasis");