Move device state distribution to Stasis-core

In the move from Asterisk's event system to Stasis, this makes
distributed device state aggregation always-on, removes unnecessary
task processors where possible, and collapses aggregate and
non-aggregate states into a single cache for ease of retrieval. This
also removes an intermediary step in device state aggregation.

Review: https://reviewboard.asterisk.org/r/2389/
(closes issue ASTERISK-21101)
Patch-by: Kinsey Moore <kmoore@digium.com>


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@385860 65c4cc65-6c06-0410-ace0-fbb531ad65f3

10 files changed, 691 insertions, 427 deletions

diff --git a/apps/app_queue.c b/apps/app_queue.c
index fd692a4b2..9de87892c 100644
--- a/apps/app_queue.c
+++ b/apps/app_queue.c
@@ -990,9 +990,6 @@ static const struct autopause {
 	{ QUEUE_AUTOPAUSE_ALL,"all" },
 };
 
-
-static struct ast_taskprocessor *devicestate_tps;
-
 #define DEFAULT_RETRY		5
 #define DEFAULT_TIMEOUT		15
 #define RECHECK			1		/*!< Recheck every second to see we we're at the top yet */
@@ -1037,8 +1034,8 @@ static int montype_default = 0;
 /*! \brief queues.conf [general] option */
 static int shared_lastcall = 1;
 
-/*! \brief Subscription to device state change events */
-static struct ast_event_sub *device_state_sub;
+/*! \brief Subscription to device state change messages */
+static struct stasis_subscription *device_state_sub;
 
 /*! \brief queues.conf [general] option */
 static int update_cdr = 0;
@@ -1618,12 +1615,6 @@ static int get_member_status(struct call_queue *q, int max_penalty, int min_pena
 	return -1;
 }
 
-struct statechange {
-	AST_LIST_ENTRY(statechange) entry;
-	int state;
-	char dev[0];
-};
-
 /*! \brief set a member's status based on device state of that member's state_interface.
  *
  * Lock interface list find sc, iterate through each queues queue_member list for member to
@@ -1742,10 +1733,10 @@ static int is_member_available(struct member *mem)
 }
 
 /*! \brief set a member's status based on device state of that member's interface*/
-static int handle_statechange(void *datap)
+static void device_state_cb(void *unused, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg)
 {
-	struct statechange *sc = datap;
 	struct ao2_iterator miter, qiter;
+	struct ast_device_state_message *dev_state;
 	struct member *m;
 	struct call_queue *q;
 	char interface[80], *slash_pos;
@@ -1753,6 +1744,16 @@ static int handle_statechange(void *datap)
 	int found_member;		/* Found this member in this queue */
 	int avail = 0;			/* Found an available member in this queue */
 
+	if (ast_device_state_message_type() != stasis_message_type(msg)) {
+		return;
+	}
+
+	dev_state = stasis_message_data(msg);
+	if (dev_state->eid) {
+		/* ignore non-aggregate states */
+		return;
+	}
+
 	qiter = ao2_iterator_init(queues, 0);
 	while ((q = ao2_t_iterator_next(&qiter, "Iterate over queues"))) {
 		ao2_lock(q);
@@ -1770,9 +1771,9 @@ static int handle_statechange(void *datap)
 					}
 				}
 
-				if (!strcasecmp(interface, sc->dev)) {
+				if (!strcasecmp(interface, dev_state->device)) {
 					found_member = 1;
-					update_status(q, m, sc->state);
+					update_status(q, m, dev_state->state);
 				}
 			}
 
@@ -1804,39 +1805,18 @@ static int handle_statechange(void *datap)
 	ao2_iterator_destroy(&qiter);
 
 	if (found) {
-		ast_debug(1, "Device '%s' changed to state '%d' (%s)\n", sc->dev, sc->state, ast_devstate2str(sc->state));
+		ast_debug(1, "Device '%s' changed to state '%d' (%s)\n",
+			dev_state->device,
+			dev_state->state,
+			ast_devstate2str(dev_state->state));
 	} else {
-		ast_debug(3, "Device '%s' changed to state '%d' (%s) but we don't care because they're not a member of any queue.\n", sc->dev, sc->state, ast_devstate2str(sc->state));
+		ast_debug(3, "Device '%s' changed to state '%d' (%s) but we don't care because they're not a member of any queue.\n",
+			dev_state->device,
+			dev_state->state,
+			ast_devstate2str(dev_state->state));
 	}
 
-	ast_free(sc);
-	return 0;
-}
-
-static void device_state_cb(const struct ast_event *event, void *unused)
-{
-	enum ast_device_state state;
-	const char *device;
-	struct statechange *sc;
-	size_t datapsize;
-
-	state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
-	device = ast_event_get_ie_str(event, AST_EVENT_IE_DEVICE);
-
-	if (ast_strlen_zero(device)) {
-		ast_log(LOG_ERROR, "Received invalid event that had no device IE\n");
-		return;
-	}
-	datapsize = sizeof(*sc) + strlen(device) + 1;
-	if (!(sc = ast_calloc(1, datapsize))) {
-		ast_log(LOG_ERROR, "failed to calloc a state change struct\n");
-		return;
-	}
-	sc->state = state;
-	strcpy(sc->dev, device);
-	if (ast_taskprocessor_push(devicestate_tps, handle_statechange, sc) < 0) {
-		ast_free(sc);
-	}
+	return;
 }
 
 /*! \brief Helper function which converts from extension state to device state values */
@@ -9876,8 +9856,9 @@ static int unload_module(void)
 
 	res |= ast_data_unregister(NULL);
 
-	if (device_state_sub)
-		ast_event_unsubscribe(device_state_sub);
+	if (device_state_sub) {
+		device_state_sub = stasis_unsubscribe(device_state_sub);
+	}
 
 	ast_extension_state_del(0, extension_state_cb);
 
@@ -9887,7 +9868,6 @@ static int unload_module(void)
 		queue_t_unref(q, "Done with iterator");
 	}
 	ao2_iterator_destroy(&q_iter);
-	devicestate_tps = ast_taskprocessor_unreference(devicestate_tps);
 	ao2_ref(queues, -1);
 	ast_unload_realtime("queue_members");
 	return res;
@@ -9948,12 +9928,8 @@ static int load_module(void)
 	res |= ast_custom_function_register(&queuewaitingcount_function);
 	res |= ast_custom_function_register(&queuememberpenalty_function);
 
-	if (!(devicestate_tps = ast_taskprocessor_get("app_queue", 0))) {
-		ast_log(LOG_WARNING, "devicestate taskprocessor reference failed - devicestate notifications will not occur\n");
-	}
-
 	/* in the following subscribe call, do I use DEVICE_STATE, or DEVICE_STATE_CHANGE? */
-	if (!(device_state_sub = ast_event_subscribe(AST_EVENT_DEVICE_STATE, device_state_cb, "AppQueue Device state", NULL, AST_EVENT_IE_END))) {
+	if (!(device_state_sub = stasis_subscribe(ast_device_state_topic_all(), device_state_cb, NULL))) {
 		res = -1;
 	}
 
diff --git a/include/asterisk/devicestate.h b/include/asterisk/devicestate.h
index 86740bc2f..2b3353ffd 100644
--- a/include/asterisk/devicestate.h
+++ b/include/asterisk/devicestate.h
@@ -38,6 +38,7 @@
 #define _ASTERISK_DEVICESTATE_H
 
 #include "asterisk/channelstate.h"
+#include "asterisk/utils.h"
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {
@@ -270,19 +271,87 @@ struct ast_devstate_aggregate {
 };
 
 /*!
- * \brief Enable distributed device state processing.
- *
- * \details
- * By default, Asterisk assumes that device state change events will only be
- * originating from one instance.  If a module gets loaded and configured such
- * that multiple instances of Asterisk will be sharing device state, this
- * function should be called to enable distributed device state processing.
- * It is off by default to save on unnecessary processing.
- *
- * \retval 0 success
- * \retval -1 failure
+ * \brief The structure that contains device state
+ * \since 12
+ */
+struct ast_device_state_message {
+	AST_DECLARE_STRING_FIELDS(
+		AST_STRING_FIELD(cache_id);	/*!< A unique ID used for hashing */
+		AST_STRING_FIELD(device);	/*!< The name of the device */
+	);
+	enum ast_device_state state;		/*!< The state of the device */
+	struct ast_eid *eid;			/*!< The EID of the server where this message originated, NULL EID means aggregate state */
+	enum ast_devstate_cache cachable;	/*!< Flag designating the cachability of this device state */
+};
+
+/*!
+ * \brief Get the Stasis topic for device state messages
+ * \retval The topic for device state messages
+ * \retval NULL if it has not been allocated
+ * \since 12
+ */
+struct stasis_topic *ast_device_state_topic_all(void);
+
+/*!
+ * \brief Get the Stasis topic for device state messages for a specific device
+ * \param uniqueid The device for which to get the topic
+ * \retval The topic structure for MWI messages for a given device
+ * \retval NULL if it failed to be found or allocated
+ * \since 12
+ */
+struct stasis_topic *ast_device_state_topic(const char *device);
+
+/*!
+ * \brief Get the Stasis caching topic for device state messages
+ * \retval The caching topic for device state messages
+ * \retval NULL if it has not been allocated
+ * \since 12
+ */
+struct stasis_caching_topic *ast_device_state_topic_cached(void);
+
+/*!
+ * \brief Get the Stasis message type for device state messages
+ * \retval The message type for device state messages
+ * \retval NULL if it has not been allocated
+ * \since 12
+ */
+struct stasis_message_type *ast_device_state_message_type(void);
+
+/*!
+ * \brief Initialize the device state core
+ * \retval 0 Success
+ * \retval -1 Failure
+ * \since 12
+ */
+int devstate_init(void);
+
+/*!
+ * \brief Publish a device state update
+ * \param[in] device The device name
+ * \param[in] state The state of the device
+ * \param[in] cachable Whether the device state can be cached
+ * \retval 0 Success
+ * \retval -1 Failure
+ * \since 12
+ */
+#define ast_publish_device_state(device, state, cachable) \
+	ast_publish_device_state_full(device, state, cachable, &ast_eid_default)
+
+/*!
+ * \brief Publish a device state update with EID
+ * \param[in] device The device name
+ * \param[in] state The state of the device
+ * \param[in] cachable Whether the device state can be cached
+ * \param[in] eid The EID of the server that originally published the message
+ * \retval 0 Success
+ * \retval -1 Failure
+ * \since 12
  */
-int ast_enable_distributed_devstate(void);
+int ast_publish_device_state_full(
+			const char *device,
+			enum ast_device_state state,
+			enum ast_devstate_cache cachable,
+			struct ast_eid *eid);
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }
diff --git a/include/asterisk/xmpp.h b/include/asterisk/xmpp.h
index 6833b6cce..6d14b1115 100644
--- a/include/asterisk/xmpp.h
+++ b/include/asterisk/xmpp.h
@@ -47,6 +47,7 @@
 #include "asterisk/linkedlists.h"
 #include "asterisk/stringfields.h"
 #include "asterisk/pbx.h"
+#include "asterisk/stasis.h"
 
 /*
  * As per RFC 3920 - section 3.1, the maximum length for a full Jabber ID
@@ -135,7 +136,7 @@ struct ast_xmpp_client {
 	int timeout;
 	unsigned int reconnect:1; /*!< Reconnect this client */
 	struct stasis_subscription *mwi_sub; /*!< If distributing event information the MWI subscription */
-	struct ast_event_sub *device_state_sub; /*!< If distributing event information the device state subscription */
+	struct stasis_subscription *device_state_sub; /*!< If distributing event information the device state subscription */
 };
 
 /*!
diff --git a/main/asterisk.c b/main/asterisk.c
index d7eb8d953..f9ff163e6 100644
--- a/main/asterisk.c
+++ b/main/asterisk.c
@@ -4180,6 +4180,11 @@ int main(int argc, char *argv[])
 
 	aco_init();
 
+	if (devstate_init()) {
+		printf("Device state core initialization failed.\n%s", term_quit());
+		exit(1);
+	}
+
 	if (app_init()) {
 		printf("App core initialization failed.\n%s", term_quit());
 		exit(1);
diff --git a/main/ccss.c b/main/ccss.c
index b479a3c54..6b59a2f37 100644
--- a/main/ccss.c
+++ b/main/ccss.c
@@ -1209,7 +1209,7 @@ struct generic_monitor_instance_list {
 	 * recalled
 	 */
 	int fit_for_recall;
-	struct ast_event_sub *sub;
+	struct stasis_subscription *sub;
 	AST_LIST_HEAD_NOLOCK(, generic_monitor_instance) list;
 };
 
@@ -1260,19 +1260,20 @@ static void generic_monitor_instance_list_destructor(void *obj)
 	struct generic_monitor_instance_list *generic_list = obj;
 	struct generic_monitor_instance *generic_instance;
 
-	generic_list->sub = ast_event_unsubscribe(generic_list->sub);
+	generic_list->sub = stasis_unsubscribe(generic_list->sub);
 	while ((generic_instance = AST_LIST_REMOVE_HEAD(&generic_list->list, next))) {
 		ast_free(generic_instance);
 	}
 	ast_free((char *)generic_list->device_name);
 }
 
-static void generic_monitor_devstate_cb(const struct ast_event *event, void *userdata);
+static void generic_monitor_devstate_cb(void *userdata, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg);
 static struct generic_monitor_instance_list *create_new_generic_list(struct ast_cc_monitor *monitor)
 {
 	struct generic_monitor_instance_list *generic_list = ao2_t_alloc(sizeof(*generic_list),
 			generic_monitor_instance_list_destructor, "allocate generic monitor instance list");
 	char * device_name;
+	struct stasis_topic *device_specific_topic;
 
 	if (!generic_list) {
 		return NULL;
@@ -1285,11 +1286,12 @@ static struct generic_monitor_instance_list *create_new_generic_list(struct ast_
 	ast_tech_to_upper(device_name);
 	generic_list->device_name = device_name;
 
-	if (!(generic_list->sub = ast_event_subscribe(AST_EVENT_DEVICE_STATE,
-		generic_monitor_devstate_cb, "Requesting CC", NULL,
-		AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, monitor->interface->device_name,
-		AST_EVENT_IE_STATE, AST_EVENT_IE_PLTYPE_EXISTS,
-		AST_EVENT_IE_END))) {
+	device_specific_topic = ast_device_state_topic(device_name);
+	if (!device_specific_topic) {
+		return NULL;
+	}
+
+	if (!(generic_list->sub = stasis_subscribe(device_specific_topic, generic_monitor_devstate_cb, NULL))) {
 		cc_unref(generic_list, "Failed to subscribe to device state");
 		return NULL;
 	}
@@ -1298,35 +1300,25 @@ static struct generic_monitor_instance_list *create_new_generic_list(struct ast_
 	return generic_list;
 }
 
-struct generic_tp_cb_data {
-	const char *device_name;
-	enum ast_device_state new_state;
-};
-
 static int generic_monitor_devstate_tp_cb(void *data)
 {
-	struct generic_tp_cb_data *gtcd = data;
-	enum ast_device_state new_state = gtcd->new_state;
-	enum ast_device_state previous_state = gtcd->new_state;
-	const char *monitor_name = gtcd->device_name;
+	RAII_VAR(struct ast_device_state_message *, dev_state, data, ao2_cleanup);
+	enum ast_device_state new_state = dev_state->state;
+	enum ast_device_state previous_state;
 	struct generic_monitor_instance_list *generic_list;
 	struct generic_monitor_instance *generic_instance;
 
-	if (!(generic_list = find_generic_monitor_instance_list(monitor_name))) {
+	if (!(generic_list = find_generic_monitor_instance_list(dev_state->device))) {
 		/* The most likely cause for this is that we destroyed the monitor in the
 		 * time between subscribing to its device state and the time this executes.
 		 * Not really a big deal.
 		 */
-		ast_free((char *) gtcd->device_name);
-		ast_free(gtcd);
 		return 0;
 	}
 
 	if (generic_list->current_state == new_state) {
 		/* The device state hasn't actually changed, so we don't really care */
 		cc_unref(generic_list, "Kill reference of generic list in devstate taskprocessor callback");
-		ast_free((char *) gtcd->device_name);
-		ast_free(gtcd);
 		return 0;
 	}
 
@@ -1346,33 +1338,31 @@ static int generic_monitor_devstate_tp_cb(void *data)
 		}
 	}
 	cc_unref(generic_list, "Kill reference of generic list in devstate taskprocessor callback");
-	ast_free((char *) gtcd->device_name);
-	ast_free(gtcd);
 	return 0;
 }
 
-static void generic_monitor_devstate_cb(const struct ast_event *event, void *userdata)
+static void generic_monitor_devstate_cb(void *userdata, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg)
 {
 	/* Wow, it's cool that we've picked up on a state change, but we really want
 	 * the actual work to be done in the core's taskprocessor execution thread
 	 * so that all monitor operations can be serialized. Locks?! We don't need
 	 * no steenkin' locks!
 	 */
-	struct generic_tp_cb_data *gtcd = ast_calloc(1, sizeof(*gtcd));
-
-	if (!gtcd) {
+	struct ast_device_state_message *dev_state;
+	if (ast_device_state_message_type() != stasis_message_type(msg)) {
 		return;
 	}
 
-	if (!(gtcd->device_name = ast_strdup(ast_event_get_ie_str(event, AST_EVENT_IE_DEVICE)))) {
-		ast_free(gtcd);
+	dev_state = stasis_message_data(msg);
+	if (dev_state->eid) {
+		/* ignore non-aggregate states */
 		return;
 	}
-	gtcd->new_state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
 
-	if (ast_taskprocessor_push(cc_core_taskprocessor, generic_monitor_devstate_tp_cb, gtcd)) {
-		ast_free((char *)gtcd->device_name);
-		ast_free(gtcd);
+	ao2_t_ref(dev_state, +1, "Bumping dev_state ref for cc_core_taskprocessor");
+	if (ast_taskprocessor_push(cc_core_taskprocessor, generic_monitor_devstate_tp_cb, dev_state)) {
+		ao2_cleanup(dev_state);
+		return;
 	}
 }
 
@@ -2502,7 +2492,7 @@ struct cc_generic_agent_pvt {
 	 * device state of the caller in order to
 	 * determine when we may move on
 	 */
-	struct ast_event_sub *sub;
+	struct stasis_subscription *sub;
 	/*!
 	 * Scheduler id of offer timer.
 	 */
@@ -2635,34 +2625,33 @@ static int cc_generic_agent_stop_ringing(struct ast_cc_agent *agent)
 	return 0;
 }
 
-static int generic_agent_devstate_unsubscribe(void *data)
+static void generic_agent_devstate_cb(void *userdata, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg)
 {
-	struct ast_cc_agent *agent = data;
+	struct ast_cc_agent *agent = userdata;
+	enum ast_device_state new_state;
+	struct ast_device_state_message *dev_state;
 	struct cc_generic_agent_pvt *generic_pvt = agent->private_data;
 
-	if (generic_pvt->sub != NULL) {
-		generic_pvt->sub = ast_event_unsubscribe(generic_pvt->sub);
+	if (stasis_subscription_final_message(sub, msg)) {
+		cc_unref(agent, "Done holding ref for subscription");
+		return;
+	} else if (ast_device_state_message_type() != stasis_message_type(msg)) {
+		return;
 	}
-	cc_unref(agent, "Done unsubscribing from devstate");
-	return 0;
-}
 
-static void generic_agent_devstate_cb(const struct ast_event *event, void *userdata)
-{
-	struct ast_cc_agent *agent = userdata;
-	enum ast_device_state new_state;
+	dev_state = stasis_message_data(msg);
+	if (dev_state->eid) {
+		/* ignore non-aggregate states */
+		return;
+	}
 
-	new_state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
+	new_state = dev_state->state;
 	if (!cc_generic_is_device_available(new_state)) {
 		/* Not interested in this new state of the device.  It is still busy. */
 		return;
 	}
 
-	/* We can't unsubscribe from device state events here because it causes a deadlock */
-	if (ast_taskprocessor_push(cc_core_taskprocessor, generic_agent_devstate_unsubscribe,
-			cc_ref(agent, "ref agent for device state unsubscription"))) {
-		cc_unref(agent, "Unref agent unsubscribing from devstate failed");
-	}
+	generic_pvt->sub = stasis_unsubscribe(sub);
 	ast_cc_agent_caller_available(agent->core_id, "%s is no longer busy", agent->device_name);
 }
 
@@ -2670,18 +2659,21 @@ static int cc_generic_agent_start_monitoring(struct ast_cc_agent *agent)
 {
 	struct cc_generic_agent_pvt *generic_pvt = agent->private_data;
 	struct ast_str *str = ast_str_alloca(128);
+	struct stasis_topic *device_specific_topic;
 
 	ast_assert(generic_pvt->sub == NULL);
 	ast_str_set(&str, 0, "Agent monitoring %s device state since it is busy\n",
 		agent->device_name);
 
-	if (!(generic_pvt->sub = ast_event_subscribe(AST_EVENT_DEVICE_STATE,
-		generic_agent_devstate_cb, ast_str_buffer(str), agent,
-		AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, agent->device_name,
-		AST_EVENT_IE_STATE, AST_EVENT_IE_PLTYPE_EXISTS,
-		AST_EVENT_IE_END))) {
+	device_specific_topic = ast_device_state_topic(agent->device_name);
+	if (!device_specific_topic) {
+		return -1;
+	}
+
+	if (!(generic_pvt->sub = stasis_subscribe(device_specific_topic, generic_agent_devstate_cb, agent))) {
 		return -1;
 	}
+	cc_ref(agent, "Ref agent for subscription");
 	return 0;
 }
 
@@ -2792,7 +2784,7 @@ static void cc_generic_agent_destructor(struct ast_cc_agent *agent)
 
 	cc_generic_agent_stop_offer_timer(agent);
 	if (agent_pvt->sub) {
-		agent_pvt->sub = ast_event_unsubscribe(agent_pvt->sub);
+		agent_pvt->sub = stasis_unsubscribe(agent_pvt->sub);
 	}
 
 	ast_free(agent_pvt);
diff --git a/main/devicestate.c b/main/devicestate.c
index 4ed51f9e3..40b9e55e0 100644
--- a/main/devicestate.c
+++ b/main/devicestate.c
@@ -129,7 +129,12 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/devicestate.h"
 #include "asterisk/pbx.h"
 #include "asterisk/app.h"
+#include "asterisk/astobj2.h"
+#include "asterisk/stasis.h"
 #include "asterisk/event.h"
+#include "asterisk/devicestate.h"
+
+#define DEVSTATE_TOPIC_BUCKETS 57
 
 /*! \brief Device state strings for printing */
 static const char * const devstatestring[][2] = {
@@ -188,25 +193,12 @@ static pthread_t change_thread = AST_PTHREADT_NULL;
 /*! \brief Flag for the queue */
 static ast_cond_t change_pending;
 
-struct devstate_change {
-	AST_LIST_ENTRY(devstate_change) entry;
-	uint32_t state;
-	struct ast_eid eid;
-	enum ast_devstate_cache cachable;
-	char device[1];
-};
+struct stasis_subscription *devstate_message_sub;
 
-static struct {
-	pthread_t thread;
-	struct ast_event_sub *event_sub;
-	ast_cond_t cond;
-	ast_mutex_t lock;
-	AST_LIST_HEAD_NOLOCK(, devstate_change) devstate_change_q;
-	unsigned int enabled:1;
-} devstate_collector = {
-	.thread = AST_PTHREADT_NULL,
-	.enabled = 0,
-};
+static struct stasis_topic *device_state_topic_all;
+static struct stasis_caching_topic *device_state_topic_cached;
+static struct stasis_message_type *device_state_message_type;
+static struct stasis_topic_pool *device_state_topic_pool;
 
 /* Forward declarations */
 static int getproviderstate(const char *provider, const char *address);
@@ -289,21 +281,16 @@ enum ast_device_state ast_parse_device_state(const char *device)
 
 static enum ast_device_state devstate_cached(const char *device)
 {
-	enum ast_device_state res = AST_DEVICE_UNKNOWN;
-	struct ast_event *event;
-
-	event = ast_event_get_cached(AST_EVENT_DEVICE_STATE,
-		AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
-		AST_EVENT_IE_END);
-
-	if (!event)
-		return res;
+	RAII_VAR(struct stasis_message *, cached_msg, NULL, ao2_cleanup);
+	struct ast_device_state_message *device_state;
 
-	res = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
-
-	ast_event_destroy(event);
+	cached_msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), device);
+	if (!cached_msg) {
+		return AST_DEVICE_UNKNOWN;
+	}
+	device_state = stasis_message_data(cached_msg);
 
-	return res;
+	return device_state->state;
 }
 
 /*! \brief Check device state through channel specific function or generic function */
@@ -426,39 +413,9 @@ static int getproviderstate(const char *provider, const char *address)
 	return res;
 }
 
-static void devstate_event(const char *device, enum ast_device_state state, int cachable)
-{
-	struct ast_event *event;
-	enum ast_event_type event_type;
-
-	if (devstate_collector.enabled) {
-		/* Distributed device state is enabled, so this state change is a change
-		 * for a single server, not the real state. */
-		event_type = AST_EVENT_DEVICE_STATE_CHANGE;
-	} else {
-		event_type = AST_EVENT_DEVICE_STATE;
-	}
-
-	ast_debug(3, "device '%s' state '%d'\n", device, state);
-
-	if (!(event = ast_event_new(event_type,
-				    AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
-				    AST_EVENT_IE_STATE, AST_EVENT_IE_PLTYPE_UINT, state,
-				    AST_EVENT_IE_CACHABLE, AST_EVENT_IE_PLTYPE_UINT, cachable,
-				    AST_EVENT_IE_END))) {
-		return;
-	}
-
-	if (cachable) {
-		ast_event_queue_and_cache(event);
-	} else {
-		ast_event_queue(event);
-	}
-}
-
 /*! Called by the state change thread to find out what the state is, and then
  *  to queue up the state change event */
-static void do_state_change(const char *device, int cachable)
+static void do_state_change(const char *device, enum ast_devstate_cache cachable)
 {
 	enum ast_device_state state;
 
@@ -466,7 +423,7 @@ static void do_state_change(const char *device, int cachable)
 
 	ast_debug(3, "Changing state for %s - state %d (%s)\n", device, state, ast_devstate2str(state));
 
-	devstate_event(device, state, cachable);
+	ast_publish_device_state(device, state, cachable);
 }
 
 int ast_devstate_changed_literal(enum ast_device_state state, enum ast_devstate_cache cachable, const char *device)
@@ -490,7 +447,7 @@ int ast_devstate_changed_literal(enum ast_device_state state, enum ast_devstate_
 	 */
 
 	if (state != AST_DEVICE_UNKNOWN) {
-		devstate_event(device, state, cachable);
+		ast_publish_device_state(device, state, cachable);
 	} else if (change_thread == AST_PTHREADT_NULL || !(change = ast_calloc(1, sizeof(*change) + strlen(device)))) {
 		/* we could not allocate a change struct, or */
 		/* there is no background thread, so process the change now */
@@ -562,176 +519,148 @@ static void *do_devstate_changes(void *data)
 	return NULL;
 }
 
-static void destroy_devstate_change(struct devstate_change *sc)
-{
-	ast_free(sc);
-}
-
 #define MAX_SERVERS 64
-struct change_collection {
-	struct devstate_change states[MAX_SERVERS];
-	size_t num_states;
-};
-
-static void devstate_cache_cb(const struct ast_event *event, void *data)
+static int devstate_change_aggregator_cb(void *obj, void *arg, void *data, int flags)
 {
-	struct change_collection *collection = data;
-	int i;
-	const struct ast_eid *eid;
+	struct stasis_message *msg = obj;
+	struct ast_devstate_aggregate *aggregate = arg;
+	char *device = data;
+	struct ast_device_state_message *device_state = stasis_message_data(msg);
 
-	if (collection->num_states == ARRAY_LEN(collection->states)) {
-		ast_log(LOG_ERROR, "More per-server state values than we have room for (MAX_SERVERS is %d)\n",
-			MAX_SERVERS);
-		return;
-	}
-
-	if (!(eid = ast_event_get_ie_raw(event, AST_EVENT_IE_EID))) {
-		ast_log(LOG_ERROR, "Device state change event with no EID\n");
-		return;
+	if (!device_state->eid || strcmp(device, device_state->device)) {
+		/* ignore aggregate states and devices that don't match */
+		return 0;
 	}
-
-	i = collection->num_states;
-
-	collection->states[i].state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
-	collection->states[i].eid = *eid;
-
-	collection->num_states++;
+	ast_debug(1, "Adding per-server state of '%s' for '%s'\n",
+		ast_devstate2str(device_state->state), device);
+	ast_devstate_aggregate_add(aggregate, device_state->state);
+	return 0;
 }
 
-static void process_collection(const char *device, enum ast_devstate_cache cachable, struct change_collection *collection)
+static void device_state_dtor(void *obj)
 {
-	int i;
-	struct ast_devstate_aggregate agg;
-	enum ast_device_state state;
-	struct ast_event *event;
+	struct ast_device_state_message *device_state = obj;
+	ast_string_field_free_memory(device_state);
+	ast_free(device_state->eid);
+}
 
-	ast_devstate_aggregate_init(&agg);
+static struct ast_device_state_message *device_state_alloc(const char *device, enum ast_device_state state, enum ast_devstate_cache cachable, const struct ast_eid *eid)
+{
+	RAII_VAR(struct ast_device_state_message *, new_device_state, ao2_alloc(sizeof(*new_device_state), device_state_dtor), ao2_cleanup);
 
-	for (i = 0; i < collection->num_states; i++) {
-		ast_debug(1, "Adding per-server state of '%s' for '%s'\n",
-			ast_devstate2str(collection->states[i].state), device);
-		ast_devstate_aggregate_add(&agg, collection->states[i].state);
+	if (!new_device_state || ast_string_field_init(new_device_state, 256)) {
+		return NULL;
 	}
 
-	state = ast_devstate_aggregate_result(&agg);
+	ast_string_field_set(new_device_state, device, device);
+	new_device_state->state = state;
+	new_device_state->cachable = cachable;
 
-	ast_debug(1, "Aggregate devstate result is '%s' for '%s'\n",
-		ast_devstate2str(state), device);
+	if (eid) {
+		char eid_str[20];
+		struct ast_str *cache_id = ast_str_alloca(256);
 
-	event = ast_event_get_cached(AST_EVENT_DEVICE_STATE,
-		AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
-		AST_EVENT_IE_END);
-
-	if (event) {
-		enum ast_device_state old_state;
+		new_device_state->eid = ast_malloc(sizeof(*eid));
+		if (!new_device_state->eid) {
+			return NULL;
+		}
 
-		old_state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
+		*new_device_state->eid = *eid;
+		ast_eid_to_str(eid_str, sizeof(eid_str), new_device_state->eid);
+		ast_str_set(&cache_id, 0, "%s%s", eid_str, device);
+		ast_string_field_set(new_device_state, cache_id, ast_str_buffer(cache_id));
+	} else {
+		/* no EID makes this an aggregate state */
+		ast_string_field_set(new_device_state, cache_id, device);
+	}
 
-		ast_event_destroy(event);
+	ao2_ref(new_device_state, +1);
+	return new_device_state;
+}
 
-		if (state == old_state) {
-			/* No change since last reported device state */
-			ast_debug(1, "Aggregate state for device '%s' has not changed from '%s'\n",
-				device, ast_devstate2str(state));
-			return;
-		}
-	}
+static enum ast_device_state get_aggregate_state(char *device)
+{
+	RAII_VAR(struct ao2_container *, cached, NULL, ao2_cleanup);
+	struct ast_devstate_aggregate aggregate;
 
-	ast_debug(1, "Aggregate state for device '%s' has changed to '%s'\n",
-		device, ast_devstate2str(state));
+	ast_devstate_aggregate_init(&aggregate);
 
-	event = ast_event_new(AST_EVENT_DEVICE_STATE,
-		AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
-		AST_EVENT_IE_STATE, AST_EVENT_IE_PLTYPE_UINT, state,
-		AST_EVENT_IE_END);
+	cached = stasis_cache_dump(ast_device_state_topic_cached(), NULL);
 
-	if (!event) {
-		return;
-	}
+	ao2_callback_data(cached, OBJ_NODATA, devstate_change_aggregator_cb, &aggregate, device);
 
-	if (cachable) {
-		ast_event_queue_and_cache(event);
-	} else {
-		ast_event_queue(event);
-	}
+	return ast_devstate_aggregate_result(&aggregate);
 }
 
-static void handle_devstate_change(struct devstate_change *sc)
+static int aggregate_state_changed(char *device, enum ast_device_state new_aggregate_state)
 {
-	struct ast_event_sub *tmp_sub;
-	struct change_collection collection = {
-		.num_states = 0,
-	};
-
-	ast_debug(1, "Processing device state change for '%s'\n", sc->device);
+	RAII_VAR(struct stasis_message *, cached_aggregate_msg, NULL, ao2_cleanup);
+	struct ast_device_state_message *cached_aggregate_device_state;
 
-	if (!(tmp_sub = ast_event_subscribe_new(AST_EVENT_DEVICE_STATE_CHANGE, devstate_cache_cb, &collection))) {
-		ast_log(LOG_ERROR, "Failed to create subscription\n");
-		return;
+	cached_aggregate_msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), device);
+	if (!cached_aggregate_msg) {
+		return 1;
 	}
 
-	if (ast_event_sub_append_ie_str(tmp_sub, AST_EVENT_IE_DEVICE, sc->device)) {
-		ast_log(LOG_ERROR, "Failed to append device IE\n");
-		ast_event_sub_destroy(tmp_sub);
-		return;
+	cached_aggregate_device_state = stasis_message_data(cached_aggregate_msg);
+	if (cached_aggregate_device_state->state == new_aggregate_state) {
+		return 0;
 	}
-
-	/* Populate the collection of device states from the cache */
-	ast_event_dump_cache(tmp_sub);
-
-	process_collection(sc->device, sc->cachable, &collection);
-
-	ast_event_sub_destroy(tmp_sub);
+	return 1;
 }
 
-static void *run_devstate_collector(void *data)
+static void devstate_change_collector_cb(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg)
 {
-	for (;;) {
-		struct devstate_change *sc;
+	enum ast_device_state aggregate_state;
+	char *device;
+	struct ast_device_state_message *device_state;
+	RAII_VAR(struct stasis_message *, new_aggregate_msg, NULL, ao2_cleanup);
+	RAII_VAR(struct ast_device_state_message *, new_aggregate_state, NULL, ao2_cleanup);
+
+	if (stasis_cache_update_type() == stasis_message_type(msg)) {
+		struct stasis_cache_update *update = stasis_message_data(msg);
+		if (!update->new_snapshot) {
+			return;
+		}
+		msg = update->new_snapshot;
+	}
 
-		ast_mutex_lock(&devstate_collector.lock);
-		while (!(sc = AST_LIST_REMOVE_HEAD(&devstate_collector.devstate_change_q, entry)))
-			ast_cond_wait(&devstate_collector.cond, &devstate_collector.lock);
-		ast_mutex_unlock(&devstate_collector.lock);
+	if (ast_device_state_message_type() != stasis_message_type(msg)) {
+		return;
+	}
 
-		handle_devstate_change(sc);
+	device_state = stasis_message_data(msg);
 
-		destroy_devstate_change(sc);
+	if (!device_state->eid) {
+		/* ignore aggregate messages */
+		return;
 	}
 
-	return NULL;
-}
+	device = ast_strdupa(device_state->device);
+	ast_debug(1, "Processing device state change for '%s'\n", device);
 
-static void devstate_change_collector_cb(const struct ast_event *event, void *data)
-{
-	struct devstate_change *sc;
-	const char *device;
-	const struct ast_eid *eid;
-	uint32_t state;
-	enum ast_devstate_cache cachable = AST_DEVSTATE_CACHABLE;
+	if (device_state->cachable == AST_DEVSTATE_NOT_CACHABLE) {
+		/* if it's not cachable, there will be no aggregate state to get
+		 * and this should be passed through */
+		aggregate_state = device_state->state;
+	} else {
 
-	device = ast_event_get_ie_str(event, AST_EVENT_IE_DEVICE);
-	eid = ast_event_get_ie_raw(event, AST_EVENT_IE_EID);
-	state = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
-	cachable = ast_event_get_ie_uint(event, AST_EVENT_IE_CACHABLE);
+		aggregate_state = get_aggregate_state(device);
+		ast_debug(1, "Aggregate devstate result is '%s' for '%s'\n",
+			ast_devstate2str(aggregate_state), device);
 
-	if (ast_strlen_zero(device) || !eid) {
-		ast_log(LOG_ERROR, "Invalid device state change event received\n");
-		return;
+		if (!aggregate_state_changed(device, aggregate_state)) {
+			/* No change since last reported device state */
+			ast_debug(1, "Aggregate state for device '%s' has not changed from '%s'\n",
+				device, ast_devstate2str(aggregate_state));
+			return;
+		}
 	}
 
-	if (!(sc = ast_calloc(1, sizeof(*sc) + strlen(device))))
-		return;
-
-	strcpy(sc->device, device);
-	sc->eid = *eid;
-	sc->state = state;
-	sc->cachable = cachable;
+	ast_debug(1, "Aggregate state for device '%s' has changed to '%s'\n",
+		device, ast_devstate2str(aggregate_state));
 
-	ast_mutex_lock(&devstate_collector.lock);
-	AST_LIST_INSERT_TAIL(&devstate_collector.devstate_change_q, sc, entry);
-	ast_cond_signal(&devstate_collector.cond);
-	ast_mutex_unlock(&devstate_collector.lock);
+	ast_publish_device_state_full(device, aggregate_state, device_state->cachable, NULL);
 }
 
 /*! \brief Initialize the device state engine in separate thread */
@@ -784,28 +713,106 @@ enum ast_device_state ast_devstate_aggregate_result(struct ast_devstate_aggregat
 	return agg->state;
 }
 
-int ast_enable_distributed_devstate(void)
+struct stasis_topic *ast_device_state_topic_all(void)
 {
-	if (devstate_collector.enabled) {
-		return 0;
+	return device_state_topic_all;
+}
+
+struct stasis_caching_topic *ast_device_state_topic_cached(void)
+{
+	return device_state_topic_cached;
+}
+
+struct stasis_message_type *ast_device_state_message_type(void)
+{
+	return device_state_message_type;
+}
+
+struct stasis_topic *ast_device_state_topic(const char *device)
+{
+	return stasis_topic_pool_get_topic(device_state_topic_pool, device);
+}
+
+int ast_publish_device_state_full(
+			const char *device,
+			enum ast_device_state state,
+			enum ast_devstate_cache cachable,
+			struct ast_eid *eid)
+{
+	RAII_VAR(struct ast_device_state_message *, device_state, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_message *, message, NULL, ao2_cleanup);
+	struct stasis_topic *device_specific_topic;
+
+	ast_assert(!ast_strlen_zero(device));
+
+	device_state = device_state_alloc(device, state, cachable, eid);
+	if (!device_state) {
+		return -1;
 	}
 
-	devstate_collector.event_sub = ast_event_subscribe(AST_EVENT_DEVICE_STATE_CHANGE,
-		devstate_change_collector_cb, "devicestate_engine_enable_distributed", NULL, AST_EVENT_IE_END);
+	message = stasis_message_create(ast_device_state_message_type(), device_state);
 
-	if (!devstate_collector.event_sub) {
-		ast_log(LOG_ERROR, "Failed to create subscription for the device state change collector\n");
+	device_specific_topic = ast_device_state_topic(device);
+	if (!device_specific_topic) {
 		return -1;
 	}
 
-	ast_mutex_init(&devstate_collector.lock);
-	ast_cond_init(&devstate_collector.cond, NULL);
-	if (ast_pthread_create_background(&devstate_collector.thread, NULL, run_devstate_collector, NULL) < 0) {
-		ast_log(LOG_ERROR, "Unable to start device state collector thread.\n");
+	stasis_publish(device_specific_topic, message);
+	return 0;
+}
+
+static const char *device_state_get_id(struct stasis_message *message)
+{
+	struct ast_device_state_message *device_state;
+	if (ast_device_state_message_type() != stasis_message_type(message)) {
+		return NULL;
+	}
+
+	device_state = stasis_message_data(message);
+	if (device_state->cachable == AST_DEVSTATE_NOT_CACHABLE) {
+		return NULL;
+	}
+
+	return device_state->cache_id;
+}
+
+static void devstate_exit(void)
+{
+	ao2_cleanup(device_state_topic_all);
+	device_state_topic_all = NULL;
+	device_state_topic_cached = stasis_caching_unsubscribe(device_state_topic_cached);
+	ao2_cleanup(device_state_message_type);
+	device_state_message_type = NULL;
+	ao2_cleanup(device_state_topic_pool);
+	device_state_topic_pool = NULL;
+}
+
+int devstate_init(void)
+{
+	device_state_topic_all = stasis_topic_create("ast_device_state_topic");
+	if (!device_state_topic_all) {
+		return -1;
+	}
+	device_state_topic_cached = stasis_caching_topic_create(device_state_topic_all, device_state_get_id);
+	if (!device_state_topic_cached) {
+		return -1;
+	}
+	device_state_message_type = stasis_message_type_create("ast_device_state_message");
+	if (!device_state_message_type) {
+		return -1;
+	}
+	device_state_topic_pool = stasis_topic_pool_create(ast_device_state_topic_all());
+	if (!device_state_topic_pool) {
 		return -1;
 	}
 
-	devstate_collector.enabled = 1;
+	devstate_message_sub = stasis_subscribe(stasis_caching_get_topic(ast_device_state_topic_cached()), devstate_change_collector_cb, NULL);
+
+	if (!devstate_message_sub) {
+		ast_log(LOG_ERROR, "Failed to create subscription for the device state change collector\n");
+		return -1;
+	}
 
+	ast_register_atexit(devstate_exit);
 	return 0;
 }
diff --git a/main/pbx.c b/main/pbx.c
index 8bc0c3f5f..017896979 100644
--- a/main/pbx.c
+++ b/main/pbx.c
@@ -1130,11 +1130,6 @@ struct presencechange {
 	char *message;
 };
 
-struct statechange {
-	AST_LIST_ENTRY(statechange) entry;
-	char dev[0];
-};
-
 struct pbx_exception {
 	AST_DECLARE_STRING_FIELDS(
 		AST_STRING_FIELD(context);	/*!< Context associated with this exception */
@@ -1300,7 +1295,7 @@ static int extenpatternmatchnew = 0;
 static char *overrideswitch = NULL;
 
 /*! \brief Subscription for device state change events */
-static struct ast_event_sub *device_state_sub;
+static struct stasis_subscription *device_state_sub;
 /*! \brief Subscription for presence state change events */
 static struct ast_event_sub *presence_state_sub;
 
@@ -5247,32 +5242,40 @@ static void get_device_state_causing_channels(struct ao2_container *c)
 	ao2_iterator_destroy(&iter);
 }
 
-static int handle_statechange(void *datap)
+static void device_state_cb(void *unused, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg)
 {
+	struct ast_device_state_message *dev_state;
 	struct ast_hint *hint;
 	struct ast_str *hint_app;
 	struct ast_hintdevice *device;
 	struct ast_hintdevice *cmpdevice;
-	struct statechange *sc = datap;
 	struct ao2_iterator *dev_iter;
 	struct ao2_iterator cb_iter;
 	char context_name[AST_MAX_CONTEXT];
 	char exten_name[AST_MAX_EXTENSION];
 
+	if (ast_device_state_message_type() != stasis_message_type(msg)) {
+		return;
+	}
+
+	dev_state = stasis_message_data(msg);
+	if (dev_state->eid) {
+		/* ignore non-aggregate states */
+		return;
+	}
+
 	if (ao2_container_count(hintdevices) == 0) {
 		/* There are no hints monitoring devices. */
-		ast_free(sc);
-		return 0;
+		return;
 	}
 
 	hint_app = ast_str_create(1024);
 	if (!hint_app) {
-		ast_free(sc);
-		return -1;
+		return;
 	}
 
-	cmpdevice = ast_alloca(sizeof(*cmpdevice) + strlen(sc->dev));
-	strcpy(cmpdevice->hintdevice, sc->dev);
+	cmpdevice = ast_alloca(sizeof(*cmpdevice) + strlen(dev_state->device));
+	strcpy(cmpdevice->hintdevice, dev_state->device);
 
 	ast_mutex_lock(&context_merge_lock);/* Hold off ast_merge_contexts_and_delete */
 	dev_iter = ao2_t_callback(hintdevices,
@@ -5283,8 +5286,7 @@ static int handle_statechange(void *datap)
 	if (!dev_iter) {
 		ast_mutex_unlock(&context_merge_lock);
 		ast_free(hint_app);
-		ast_free(sc);
-		return -1;
+		return;
 	}
 
 	for (; (device = ao2_iterator_next(dev_iter)); ao2_t_ref(device, -1, "Next device")) {
@@ -5381,8 +5383,7 @@ static int handle_statechange(void *datap)
 
 	ao2_iterator_destroy(dev_iter);
 	ast_free(hint_app);
-	ast_free(sc);
-	return 0;
+	return;
 }
 
 /*!
@@ -8846,7 +8847,7 @@ void ast_merge_contexts_and_delete(struct ast_context **extcontexts, struct ast_
 
 	/*
 	 * Notify watchers of all removed hints with the same lock
-	 * environment as handle_statechange().
+	 * environment as device_state_cb().
 	 */
 	while ((saved_hint = AST_LIST_REMOVE_HEAD(&hints_removed, list))) {
 		/* this hint has been removed, notify the watchers */
@@ -11707,25 +11708,6 @@ static void presence_state_cb(const struct ast_event *event, void *unused)
 	}
 }
 
-static void device_state_cb(const struct ast_event *event, void *unused)
-{
-	const char *device;
-	struct statechange *sc;
-
-	device = ast_event_get_ie_str(event, AST_EVENT_IE_DEVICE);
-	if (ast_strlen_zero(device)) {
-		ast_log(LOG_ERROR, "Received invalid event that had no device IE\n");
-		return;
-	}
-
-	if (!(sc = ast_calloc(1, sizeof(*sc) + strlen(device) + 1)))
-		return;
-	strcpy(sc->dev, device);
-	if (ast_taskprocessor_push(extension_state_tps, handle_statechange, sc) < 0) {
-		ast_free(sc);
-	}
-}
-
 /*!
  * \internal
  * \brief Implements the hints data provider.
@@ -11786,7 +11768,7 @@ static void unload_pbx(void)
 		presence_state_sub = ast_event_unsubscribe(presence_state_sub);
 	}
 	if (device_state_sub) {
-		device_state_sub = ast_event_unsubscribe(device_state_sub);
+		device_state_sub = stasis_unsubscribe(device_state_sub);
 	}
 
 	/* Unregister builtin applications */
@@ -11833,8 +11815,7 @@ int load_pbx(void)
 	/* Register manager application */
 	ast_manager_register_xml_core("ShowDialPlan", EVENT_FLAG_CONFIG | EVENT_FLAG_REPORTING, manager_show_dialplan);
 
-	if (!(device_state_sub = ast_event_subscribe(AST_EVENT_DEVICE_STATE, device_state_cb, "pbx Device State Change", NULL,
-			AST_EVENT_IE_END))) {
+	if (!(device_state_sub = stasis_subscribe(ast_device_state_topic_all(), device_state_cb, NULL))) {
 		return -1;
 	}
 
diff --git a/res/res_jabber.c b/res/res_jabber.c
index 0ee64f969..04bc614e9 100644
--- a/res/res_jabber.c
+++ b/res/res_jabber.c
@@ -372,7 +372,7 @@ static void aji_pubsub_purge_nodes(struct aji_client *client,
 	const char* collection_name);
 static void aji_publish_mwi(struct aji_client *client, const char *mailbox,
 	const char *context, const char *oldmsgs, const char *newmsgs);
-static void aji_devstate_cb(const struct ast_event *ast_event, void *data);
+static void aji_devstate_cb(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg);
 static void aji_mwi_cb(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg);
 static iks* aji_build_publish_skeleton(struct aji_client *client, const char *node,
 				       const char *event_type, unsigned int cachable);
@@ -411,7 +411,7 @@ static char *app_ajileave = "JabberLeave";
 static struct aji_client_container clients;
 static struct aji_capabilities *capabilities = NULL;
 static struct stasis_subscription *mwi_sub = NULL;
-static struct ast_event_sub *device_state_sub = NULL;
+static struct stasis_subscription *device_state_sub = NULL;
 static ast_cond_t message_received_condition;
 static ast_mutex_t messagelock;
 
@@ -3274,25 +3274,30 @@ static void aji_mwi_cb(void *data, struct stasis_subscription *sub, struct stasi
  * \param data void pointer to ast_client structure
  * \return void
  */
-static void aji_devstate_cb(const struct ast_event *ast_event, void *data)
+static void aji_devstate_cb(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg)
 {
-	const char *device;
-	const char *device_state;
-	unsigned int cachable;
-	struct aji_client *client;
-	if (ast_eid_cmp(&ast_eid_default, ast_event_get_ie_raw(ast_event, AST_EVENT_IE_EID)))
-	{
-		/* If the event didn't originate from this server, don't send it back out. */
-		ast_debug(1, "Returning here\n");
+	struct aji_client *client = data;
+	struct ast_device_state_message *dev_state;
+
+	if (!stasis_subscription_is_subscribed(sub) || ast_device_state_message_type() != stasis_message_type(msg)) {
 		return;
 	}
 
-	client = ASTOBJ_REF((struct aji_client *) data);
-	device = ast_event_get_ie_str(ast_event, AST_EVENT_IE_DEVICE);
-	device_state = ast_devstate_str(ast_event_get_ie_uint(ast_event, AST_EVENT_IE_STATE));
-	cachable = ast_event_get_ie_uint(ast_event, AST_EVENT_IE_CACHABLE);
-	aji_publish_device_state(client, device, device_state, cachable);
-	ASTOBJ_UNREF(client, ast_aji_client_destroy);
+	dev_state = stasis_message_data(msg);
+	if (!dev_state->eid || ast_eid_cmp(&ast_eid_default, dev_state->eid)) {
+		/* If the event is aggregate or didn't originate from this server, don't send it out. */
+		return;
+	}
+
+	aji_publish_device_state(client, dev_state->device, ast_devstate_str(dev_state->state), dev_state->cachable);
+}
+
+static int cached_devstate_cb(void *obj, void *arg, int flags)
+{
+	struct stasis_message *msg = obj;
+	struct aji_client *client = arg;
+	aji_devstate_cb(client, device_state_sub, NULL, msg);
+	return 0;
 }
 
 /*!
@@ -3306,12 +3311,11 @@ static void aji_init_event_distribution(struct aji_client *client)
 		mwi_sub = stasis_subscribe(stasis_mwi_topic_all(), aji_mwi_cb, client);
 	}
 	if (!device_state_sub) {
-		if (ast_enable_distributed_devstate()) {
-			return;
-		}
-		device_state_sub = ast_event_subscribe(AST_EVENT_DEVICE_STATE_CHANGE,
-			aji_devstate_cb, "aji_devstate_subscription", client, AST_EVENT_IE_END);
-		ast_event_dump_cache(device_state_sub);
+		RAII_VAR(struct ao2_container *, cached, NULL, ao2_cleanup);
+		device_state_sub = stasis_subscribe(ast_device_state_topic_all(),
+			aji_devstate_cb, client);
+		cached = stasis_cache_dump(ast_device_state_topic_cached(), NULL);
+		ao2_callback(cached, OBJ_NODATA, cached_devstate_cb, client);
 	}
 
 	aji_pubsub_subscribe(client, "device_state");
@@ -3355,13 +3359,11 @@ static int aji_handle_pubsub_event(void *data, ikspak *pak)
 		if ((cachable_str = iks_find_cdata(item, "cachable"))) {
 			sscanf(cachable_str, "%30d", &cachable);
 		}
-		if (!(event = ast_event_new(AST_EVENT_DEVICE_STATE_CHANGE,
-					    AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, item_id, AST_EVENT_IE_STATE,
-					    AST_EVENT_IE_PLTYPE_UINT, ast_devstate_val(device_state), AST_EVENT_IE_EID,
-					    AST_EVENT_IE_PLTYPE_RAW, &pubsub_eid, sizeof(pubsub_eid),
-					    AST_EVENT_IE_END))) {
-			return IKS_FILTER_EAT;
-		}
+		ast_publish_device_state_full(item_id,
+						ast_devstate_val(device_state),
+						cachable == AST_DEVSTATE_CACHABLE ? AST_DEVSTATE_CACHABLE : AST_DEVSTATE_NOT_CACHABLE,
+						&pubsub_eid);
+		return IKS_FILTER_EAT;
 	} else if (!strcasecmp(iks_name(item_content), "mailbox")) {
 		context = strsep(&item_id, "@");
 		sscanf(iks_find_cdata(item_content, "OLDMSGS"), "%10d", &oldmsgs);
@@ -4772,7 +4774,7 @@ static int unload_module(void)
 		mwi_sub = stasis_unsubscribe(mwi_sub);
 	}
 	if (device_state_sub) {
-		ast_event_unsubscribe(device_state_sub);
+		device_state_sub = stasis_unsubscribe(device_state_sub);
 	}
 	ast_custom_function_unregister(&jabberreceive_function);
 
diff --git a/res/res_xmpp.c b/res/res_xmpp.c
index a53a8fd91..f9cfdac11 100644
--- a/res/res_xmpp.c
+++ b/res/res_xmpp.c
@@ -1352,22 +1352,22 @@ static void xmpp_pubsub_mwi_cb(void *data, struct stasis_subscription *sub, stru
  * \param data void pointer to ast_client structure
  * \return void
  */
-static void xmpp_pubsub_devstate_cb(const struct ast_event *ast_event, void *data)
+static void xmpp_pubsub_devstate_cb(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *msg)
 {
 	struct ast_xmpp_client *client = data;
-	const char *device, *device_state;
-	unsigned int cachable;
+	struct ast_device_state_message *dev_state;
 
-	if (ast_eid_cmp(&ast_eid_default, ast_event_get_ie_raw(ast_event, AST_EVENT_IE_EID))) {
-		/* If the event didn't originate from this server, don't send it back out. */
-		ast_debug(1, "Returning here\n");
+	if (!stasis_subscription_is_subscribed(sub) || ast_device_state_message_type() != stasis_message_type(msg)) {
+		return;
+	}
+
+	dev_state = stasis_message_data(msg);
+	if (!dev_state->eid || ast_eid_cmp(&ast_eid_default, dev_state->eid)) {
+		/* If the event is aggregate or didn't originate from this server, don't send it out. */
 		return;
 	}
 
-	device = ast_event_get_ie_str(ast_event, AST_EVENT_IE_DEVICE);
-	device_state = ast_devstate_str(ast_event_get_ie_uint(ast_event, AST_EVENT_IE_STATE));
-	cachable = ast_event_get_ie_uint(ast_event, AST_EVENT_IE_CACHABLE);
-	xmpp_pubsub_publish_device_state(client, device, device_state, cachable);
+	xmpp_pubsub_publish_device_state(client, dev_state->device, ast_devstate_str(dev_state->state), dev_state->cachable);
 }
 
 /*!
@@ -1474,13 +1474,11 @@ static int xmpp_pubsub_handle_event(void *data, ikspak *pak)
 		if ((cachable_str = iks_find_cdata(item, "cachable"))) {
 			sscanf(cachable_str, "%30d", &cachable);
 		}
-		if (!(event = ast_event_new(AST_EVENT_DEVICE_STATE_CHANGE,
-					    AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, item_id, AST_EVENT_IE_STATE,
-					    AST_EVENT_IE_PLTYPE_UINT, ast_devstate_val(device_state), AST_EVENT_IE_EID,
-					    AST_EVENT_IE_PLTYPE_RAW, &pubsub_eid, sizeof(pubsub_eid),
-					    AST_EVENT_IE_END))) {
-			return IKS_FILTER_EAT;
-		}
+		ast_publish_device_state_full(item_id,
+						ast_devstate_val(device_state),
+						cachable == AST_DEVSTATE_CACHABLE ? AST_DEVSTATE_CACHABLE : AST_DEVSTATE_NOT_CACHABLE,
+						&pubsub_eid);
+		return IKS_FILTER_EAT;
 	} else if (!strcasecmp(iks_name(item_content), "mailbox")) {
 		context = strsep(&item_id, "@");
 		sscanf(iks_find_cdata(item_content, "OLDMSGS"), "%10d", &oldmsgs);
@@ -1572,6 +1570,14 @@ static int xmpp_pubsub_handle_error(void *data, ikspak *pak)
 	return IKS_FILTER_EAT;
 }
 
+static int cached_devstate_cb(void *obj, void *arg, int flags)
+{
+	struct stasis_message *msg = obj;
+	struct ast_xmpp_client *client = arg;
+	xmpp_pubsub_devstate_cb(client, client->device_state_sub, NULL, msg);
+	return 0;
+}
+
 /*!
  * \brief Initialize collections for event distribution
  * \param client the configured XMPP client we use to connect to a XMPP server
@@ -1581,6 +1587,7 @@ static void xmpp_init_event_distribution(struct ast_xmpp_client *client)
 {
 	RAII_VAR(struct xmpp_config *, cfg, ao2_global_obj_ref(globals), ao2_cleanup);
 	RAII_VAR(struct ast_xmpp_client_config *, clientcfg, NULL, ao2_cleanup);
+	RAII_VAR(struct ao2_container *, cached, NULL, ao2_cleanup);
 
 	if (!cfg || !cfg->clients || !(clientcfg = xmpp_config_find(cfg->clients, client->name))) {
 		return;
@@ -1593,17 +1600,13 @@ static void xmpp_init_event_distribution(struct ast_xmpp_client *client)
 		return;
 	}
 
-	if (ast_enable_distributed_devstate()) {
-		return;
-	}
-
-	if (!(client->device_state_sub = ast_event_subscribe(AST_EVENT_DEVICE_STATE_CHANGE,
-							     xmpp_pubsub_devstate_cb, "xmpp_pubsub_devstate_subscription", client, AST_EVENT_IE_END))) {
+	if (!(client->device_state_sub = stasis_subscribe(ast_device_state_topic_all(), xmpp_pubsub_devstate_cb, client))) {
 		client->mwi_sub = stasis_unsubscribe(client->mwi_sub);
 		return;
 	}
 
-	ast_event_dump_cache(client->device_state_sub);
+	cached = stasis_cache_dump(ast_device_state_topic_cached(), NULL);
+	ao2_callback(cached, OBJ_NODATA, cached_devstate_cb, client);
 
 	xmpp_pubsub_subscribe(client, "device_state");
 	xmpp_pubsub_subscribe(client, "message_waiting");
@@ -3528,8 +3531,7 @@ int ast_xmpp_client_disconnect(struct ast_xmpp_client *client)
 	}
 
 	if (client->device_state_sub) {
-		ast_event_unsubscribe(client->device_state_sub);
-		client->device_state_sub = NULL;
+		client->device_state_sub = stasis_unsubscribe(client->device_state_sub);
 		xmpp_pubsub_unsubscribe(client, "device_state");
 	}
 
diff --git a/tests/test_devicestate.c b/tests/test_devicestate.c
index f5f209b9e..233b6e70a 100644
--- a/tests/test_devicestate.c
+++ b/tests/test_devicestate.c
@@ -39,7 +39,9 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/test.h"
 #include "asterisk/devicestate.h"
 #include "asterisk/pbx.h"
+#include "asterisk/stasis_message_router.h"
 
+#define UNIT_TEST_DEVICE_IDENTIFIER "unit_test_device_identifier"
 
 /* These arrays are the result of the 'core show device2extenstate' output. */
 static int combined_results[] = {
@@ -274,14 +276,241 @@ AST_TEST_DEFINE(device2extenstate_test)
 	return res;
 }
 
+struct consumer {
+	ast_mutex_t lock;
+	ast_cond_t out;
+	int already_out;
+	enum ast_device_state state;
+	enum ast_device_state aggregate_state;
+	int sig_on_non_aggregate_state;
+};
+
+static void consumer_dtor(void *obj) {
+	struct consumer *consumer = obj;
+
+	ast_mutex_destroy(&consumer->lock);
+	ast_cond_destroy(&consumer->out);
+}
+
+static struct consumer *consumer_create(void) {
+	RAII_VAR(struct consumer *, consumer, NULL, ao2_cleanup);
+
+	consumer = ao2_alloc(sizeof(*consumer), consumer_dtor);
+
+	if (!consumer) {
+		return NULL;
+	}
+
+	ast_mutex_init(&consumer->lock);
+	ast_cond_init(&consumer->out, NULL);
+	consumer->sig_on_non_aggregate_state = 0;
+
+	ao2_ref(consumer, +1);
+	return consumer;
+}
+
+static void consumer_exec(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *message)
+{
+	struct consumer *consumer = data;
+	RAII_VAR(struct consumer *, consumer_needs_cleanup, NULL, ao2_cleanup);
+	struct stasis_cache_update *cache_update = stasis_message_data(message);
+	struct ast_device_state_message *device_state;
+	SCOPED_MUTEX(lock, &consumer->lock);
+
+	if (!cache_update->new_snapshot) {
+		return;
+	}
+
+	device_state = stasis_message_data(cache_update->new_snapshot);
+
+	if (strcmp(device_state->device, UNIT_TEST_DEVICE_IDENTIFIER)) {
+		/* not a device state we're interested in */
+		return;
+	}
+
+	if (device_state->eid) {
+		consumer->state = device_state->state;
+		if (consumer->sig_on_non_aggregate_state) {
+			consumer->sig_on_non_aggregate_state = 0;
+			consumer->already_out = 1;
+			ast_cond_signal(&consumer->out);
+		}
+	} else {
+		consumer->aggregate_state = device_state->state;
+		consumer->already_out = 1;
+		ast_cond_signal(&consumer->out);
+	}
+}
+
+static void consumer_finalize(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *message)
+{
+	struct consumer *consumer = data;
+
+	if (stasis_subscription_final_message(sub, message)) {
+		ao2_cleanup(consumer);
+	}
+}
+
+static void consumer_wait_for(struct consumer *consumer)
+{
+	int res;
+	struct timeval start = ast_tvnow();
+	struct timespec end = {
+		.tv_sec = start.tv_sec + 10,
+		.tv_nsec = start.tv_usec * 1000
+	};
+
+	SCOPED_MUTEX(lock, &consumer->lock);
+
+	if (consumer->already_out) {
+		consumer->already_out = 0;
+	}
+
+	while(1) {
+		res = ast_cond_timedwait(&consumer->out, &consumer->lock, &end);
+		if (!res || res == ETIMEDOUT) {
+			break;
+		}
+	}
+	consumer->already_out = 0;
+}
+
+static int remove_device_states_cb(void *obj, void *arg, int flags)
+{
+	RAII_VAR(struct stasis_message *, msg, obj, ao2_cleanup);
+	struct ast_device_state_message *device_state = stasis_message_data(msg);
+	if (strcmp(UNIT_TEST_DEVICE_IDENTIFIER, device_state->device)) {
+		msg = NULL;
+		return 0;
+	}
+
+	msg = stasis_cache_clear_create(ast_device_state_message_type(), device_state->cache_id);
+	/* topic guaranteed to have been created by this point */
+	stasis_publish(ast_device_state_topic(device_state->device), msg);
+	return 0;
+}
+
+static void cache_cleanup(int unused)
+{
+	RAII_VAR(struct ao2_container *, cache_dump, NULL, ao2_cleanup);
+	/* remove all device states created during this test */
+	cache_dump = stasis_cache_dump(ast_device_state_topic_cached(), NULL);
+	if (!cache_dump) {
+		return;
+	}
+	ao2_callback(cache_dump, 0, remove_device_states_cb, NULL);
+}
+
+AST_TEST_DEFINE(device_state_aggregation_test)
+{
+	RAII_VAR(struct consumer *, consumer, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_message_router *, device_msg_router, NULL, stasis_message_router_unsubscribe);
+	RAII_VAR(struct ast_eid *, foreign_eid, NULL, ast_free);
+	RAII_VAR(int, cleanup_cache, 0, cache_cleanup);
+	int res;
+	struct ast_device_state_message *device_state;
+	struct stasis_message *msg;
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "device_state_aggregation_test";
+		info->category = "/main/devicestate/";
+		info->summary = "Tests message routing and aggregation through the Stasis device state system.";
+		info->description =
+			"Verifies that the device state system passes "
+			"messages appropriately, that the aggregator is "
+			"working properly, that the aggregate results match "
+			"the expected combined devstate, and that the cached "
+			"aggregate devstate is correct.";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	foreign_eid = ast_malloc(sizeof(*foreign_eid));
+	ast_test_validate(test, NULL != foreign_eid);
+	memset(foreign_eid, 0xFF, sizeof(*foreign_eid));
+
+	consumer = consumer_create();
+	ast_test_validate(test, NULL != consumer);
+
+	device_msg_router = stasis_message_router_create(stasis_caching_get_topic(ast_device_state_topic_cached()));
+	ast_test_validate(test, NULL != device_msg_router);
+
+	ao2_ref(consumer, +1);
+	res = stasis_message_router_add(device_msg_router, stasis_cache_update_type(), consumer_exec, consumer);
+	ast_test_validate(test, !res);
+
+	res = stasis_message_router_add(device_msg_router, stasis_subscription_change_type(), consumer_finalize, consumer);
+	ast_test_validate(test, !res);
+
+	/* push local state */
+	ast_publish_device_state(UNIT_TEST_DEVICE_IDENTIFIER, AST_DEVICE_NOT_INUSE, AST_DEVSTATE_CACHABLE);
+
+	consumer_wait_for(consumer);
+	ast_test_validate(test, AST_DEVICE_NOT_INUSE == consumer->state);
+	ast_test_validate(test, AST_DEVICE_NOT_INUSE == consumer->aggregate_state);
+
+	msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
+	device_state = stasis_message_data(msg);
+	ast_test_validate(test, AST_DEVICE_NOT_INUSE == device_state->state);
+	ao2_cleanup(msg);
+	msg = NULL;
+
+	/* push remote state */
+	/* this will not produce a new aggregate state message since the aggregate state does not change */
+	consumer->sig_on_non_aggregate_state = 1;
+	ast_publish_device_state_full(UNIT_TEST_DEVICE_IDENTIFIER, AST_DEVICE_NOT_INUSE, AST_DEVSTATE_CACHABLE, foreign_eid);
+
+	consumer_wait_for(consumer);
+	ast_test_validate(test, AST_DEVICE_NOT_INUSE == consumer->state);
+	ast_test_validate(test, AST_DEVICE_NOT_INUSE == consumer->aggregate_state);
+
+	msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
+	device_state = stasis_message_data(msg);
+	ast_test_validate(test, AST_DEVICE_NOT_INUSE == device_state->state);
+	ao2_cleanup(msg);
+	msg = NULL;
+
+	/* push remote state different from local state */
+	ast_publish_device_state_full(UNIT_TEST_DEVICE_IDENTIFIER, AST_DEVICE_INUSE, AST_DEVSTATE_CACHABLE, foreign_eid);
+
+	consumer_wait_for(consumer);
+	ast_test_validate(test, AST_DEVICE_INUSE == consumer->state);
+	ast_test_validate(test, AST_DEVICE_INUSE == consumer->aggregate_state);
+
+	msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
+	device_state = stasis_message_data(msg);
+	ast_test_validate(test, AST_DEVICE_INUSE == device_state->state);
+	ao2_cleanup(msg);
+	msg = NULL;
+
+	/* push local state that will cause aggregated state different from local non-aggregate state */
+	ast_publish_device_state(UNIT_TEST_DEVICE_IDENTIFIER, AST_DEVICE_RINGING, AST_DEVSTATE_CACHABLE);
+
+	consumer_wait_for(consumer);
+	ast_test_validate(test, AST_DEVICE_RINGING == consumer->state);
+	ast_test_validate(test, AST_DEVICE_RINGINUSE == consumer->aggregate_state);
+
+	msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
+	device_state = stasis_message_data(msg);
+	ast_test_validate(test, AST_DEVICE_RINGINUSE == device_state->state);
+	ao2_cleanup(msg);
+	msg = NULL;
+
+	return AST_TEST_PASS;
+}
+
 static int unload_module(void)
 {
 	AST_TEST_UNREGISTER(device2extenstate_test);
+	AST_TEST_UNREGISTER(device_state_aggregation_test);
 	return 0;
 }
 
 static int load_module(void)
 {
+	AST_TEST_REGISTER(device_state_aggregation_test);
 	AST_TEST_REGISTER(device2extenstate_test);
 	return AST_MODULE_LOAD_SUCCESS;
 }