6 files changed, 636 insertions, 37 deletions

diff --git a/main/asterisk.c b/main/asterisk.c
index b8deab1d4..885797f36 100644
--- a/main/asterisk.c
+++ b/main/asterisk.c
@@ -242,6 +242,7 @@ int daemon(int, int);  /* defined in libresolv of all places */
 #include "asterisk/sorcery.h"
 #include "asterisk/stasis.h"
 #include "asterisk/json.h"
+#include "asterisk/stasis_endpoints.h"
 
 #include "../defaults.h"
 
@@ -4174,6 +4175,11 @@ int main(int argc, char *argv[])
 		exit(1);
 	}
 
+	if (ast_endpoint_stasis_init()) {
+		printf("Endpoint initialization failed.\n%s", term_quit());
+		exit(1);
+	}
+
 	ast_makesocket();
 	sigemptyset(&sigs);
 	sigaddset(&sigs, SIGHUP);
diff --git a/main/astobj2.c b/main/astobj2.c
index a980ec379..8ccc36cb4 100644
--- a/main/astobj2.c
+++ b/main/astobj2.c
@@ -5780,3 +5780,41 @@ int astobj2_init(void)
 
 	return 0;
 }
+
+/* XXX TODO BUGBUG and all the other things...
+ * These functions should eventually be moved elsewhere, but the utils folder
+ * won't compile with them in strings.h
+ */
+static int str_hash(const void *obj, const int flags)
+{
+	return ast_str_hash(obj);
+}
+
+static int str_cmp(void *lhs, void *rhs, int flags)
+{
+	return strcmp(lhs, rhs) ? 0 : CMP_MATCH;
+}
+
+struct ao2_container *ast_str_container_alloc_options(enum ao2_container_opts opts, int buckets)
+{
+	return ao2_container_alloc_options(opts, buckets, str_hash, str_cmp);
+}
+
+int ast_str_container_add(struct ao2_container *str_container, const char *add)
+{
+	RAII_VAR(char *, ao2_add, ao2_alloc(strlen(add) + 1, NULL), ao2_cleanup);
+
+	if (!ao2_add) {
+		return -1;
+	}
+
+	/* safe strcpy */
+	strcpy(ao2_add, add);
+	ao2_link(str_container, ao2_add);
+	return 0;
+}
+
+void ast_str_container_remove(struct ao2_container *str_container, const char *remove)
+{
+	ao2_find(str_container, remove, OBJ_KEY | OBJ_NODATA | OBJ_UNLINK);
+}
diff --git a/main/channel_internal_api.c b/main/channel_internal_api.c
index cb9ed6744..f3293d59b 100644
--- a/main/channel_internal_api.c
+++ b/main/channel_internal_api.c
@@ -39,11 +39,13 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include <fcntl.h>
 
 #include "asterisk/channel.h"
-#include "asterisk/stringfields.h"
+#include "asterisk/channel_internal.h"
 #include "asterisk/data.h"
+#include "asterisk/endpoints.h"
 #include "asterisk/indications.h"
 #include "asterisk/stasis_channels.h"
-#include "asterisk/channel_internal.h"
+#include "asterisk/stasis_endpoints.h"
+#include "asterisk/stringfields.h"
 #include "asterisk/test.h"
 
 /*!
@@ -198,6 +200,7 @@ struct ast_channel {
 	struct timeval sending_dtmf_tv;		/*!< The time this channel started sending the current digit. (Invalid if sending_dtmf_digit is zero.) */
 	struct stasis_topic *topic;			/*!< Topic for all channel's events */
 	struct stasis_subscription *forwarder;		/*!< Subscription for event forwarding to all topic */
+	struct stasis_subscription *endpoint_forward;	/*!< Subscription for event forwarding to endpoint's topic */
 };
 
 /* AST_DATA definitions, which will probably have to be re-thought since the channel will be opaque */
@@ -1369,6 +1372,7 @@ void ast_channel_internal_cleanup(struct ast_channel *chan)
 	ast_string_field_free_memory(chan);
 
 	chan->forwarder = stasis_unsubscribe(chan->forwarder);
+	chan->endpoint_forward = stasis_unsubscribe(chan->endpoint_forward);
 
 	ao2_cleanup(chan->topic);
 	chan->topic = NULL;
@@ -1389,6 +1393,37 @@ struct stasis_topic *ast_channel_topic(struct ast_channel *chan)
 	return chan ? chan->topic : ast_channel_topic_all();
 }
 
+int ast_endpoint_add_channel(struct ast_endpoint *endpoint,
+	struct ast_channel *chan)
+{
+	RAII_VAR(struct ast_channel_snapshot *, snapshot, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
+
+	ast_assert(chan != NULL);
+	ast_assert(endpoint != NULL);
+
+	snapshot = ast_channel_snapshot_create(chan);
+	if (!snapshot) {
+		return -1;
+	}
+
+	msg = stasis_message_create(ast_channel_snapshot_type(), snapshot);
+	if (!msg) {
+		return -1;
+	}
+
+	chan->endpoint_forward =
+		stasis_forward_all(chan->topic, ast_endpoint_topic(endpoint));
+
+	if (chan->endpoint_forward == NULL) {
+		return -1;
+	}
+
+	stasis_publish(ast_endpoint_topic(endpoint), msg);
+
+	return 0;
+}
+
 void ast_channel_internal_setup_topics(struct ast_channel *chan)
 {
 	const char *topic_name = chan->uniqueid;
diff --git a/main/endpoints.c b/main/endpoints.c
new file mode 100644
index 000000000..95397f960
--- /dev/null
+++ b/main/endpoints.c
@@ -0,0 +1,338 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@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 Asterisk endpoint API.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ */
+
+/*** MODULEINFO
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/astobj2.h"
+#include "asterisk/endpoints.h"
+#include "asterisk/stasis.h"
+#include "asterisk/stasis_channels.h"
+#include "asterisk/stasis_endpoints.h"
+#include "asterisk/stasis_message_router.h"
+#include "asterisk/stringfields.h"
+
+/*! Buckets for endpoint->channel mappings. Keep it prime! */
+#define ENDPOINT_BUCKETS 127
+
+struct ast_endpoint {
+	AST_DECLARE_STRING_FIELDS(
+		AST_STRING_FIELD(tech);	/*!< Technology (SIP, IAX2, etc.). */
+		AST_STRING_FIELD(resource);	/*!< Name, unique to the tech. */
+		AST_STRING_FIELD(id);	/*!< tech/resource id */
+		);
+	/*! Endpoint's current state */
+	enum ast_endpoint_state state;
+	/*!
+	 * \brief Max channels for this endpoint. -1 means unlimited or unknown.
+	 *
+	 * Note that this simply documents the limits of an endpoint, and does
+	 * nothing to try to enforce the limit.
+	 */
+	int max_channels;
+	/*! Topic for this endpoint's messages */
+	struct stasis_topic *topic;
+	/*!
+	 * Forwarding subscription sending messages to ast_endpoint_topic_all()
+	 */
+	struct stasis_subscription *forward;
+	/*! Router for handling this endpoint's messages */
+	struct stasis_message_router *router;
+	/*! ast_str_container of channels associated with this endpoint */
+	struct ao2_container *channel_ids;
+};
+
+const char *ast_endpoint_state_to_string(enum ast_endpoint_state state)
+{
+	switch (state) {
+	case AST_ENDPOINT_UNKNOWN:
+		return "unknown";
+	case AST_ENDPOINT_OFFLINE:
+		return "offline";
+	case AST_ENDPOINT_ONLINE:
+		return "online";
+	}
+	return "?";
+}
+
+static void endpoint_publish_snapshot(struct ast_endpoint *endpoint)
+{
+	RAII_VAR(struct ast_endpoint_snapshot *, snapshot, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_message *, message, NULL, ao2_cleanup);
+
+	ast_assert(endpoint != NULL);
+	ast_assert(endpoint->topic != NULL);
+
+	snapshot = ast_endpoint_snapshot_create(endpoint);
+	if (!snapshot) {
+		return;
+	}
+	message = stasis_message_create(ast_endpoint_snapshot_type(), snapshot);
+	if (!message) {
+		return;
+	}
+	stasis_publish(endpoint->topic, message);
+}
+
+static void endpoint_dtor(void *obj)
+{
+	struct ast_endpoint *endpoint = obj;
+
+	/* The router should be shut down already */
+	ast_assert(endpoint->router == NULL);
+
+	stasis_unsubscribe(endpoint->forward);
+	endpoint->forward = NULL;
+
+	ao2_cleanup(endpoint->topic);
+	endpoint->topic = NULL;
+
+	ast_string_field_free_memory(endpoint);
+}
+
+static void endpoint_channel_snapshot(void *data,
+	struct stasis_subscription *sub, struct stasis_topic *topic,
+	struct stasis_message *message)
+{
+	struct ast_endpoint *endpoint = data;
+	struct ast_channel_snapshot *snapshot = stasis_message_data(message);
+	RAII_VAR(char *, existing_id, NULL, ao2_cleanup);
+	int publish = 0;
+
+	ast_assert(endpoint != NULL);
+	ast_assert(snapshot != NULL);
+
+	ao2_lock(endpoint);
+	existing_id = ao2_find(endpoint->channel_ids, snapshot->uniqueid,
+		OBJ_POINTER);
+	if (!existing_id) {
+		ast_str_container_add(endpoint->channel_ids,
+			snapshot->uniqueid);
+		publish = 1;
+	}
+	ao2_unlock(endpoint);
+	if (publish) {
+		endpoint_publish_snapshot(endpoint);
+	}
+}
+
+static void endpoint_cache_clear(void *data,
+	struct stasis_subscription *sub, struct stasis_topic *topic,
+	struct stasis_message *message)
+{
+	struct ast_endpoint *endpoint = data;
+	struct stasis_cache_clear *clear = stasis_message_data(message);
+
+	ast_assert(endpoint != NULL);
+	ast_assert(clear != NULL);
+
+	ao2_lock(endpoint);
+	ao2_find(endpoint->channel_ids, clear->id, OBJ_POINTER | OBJ_NODATA | OBJ_UNLINK);
+	ao2_unlock(endpoint);
+	endpoint_publish_snapshot(endpoint);
+}
+
+static void endpoint_default(void *data,
+	struct stasis_subscription *sub, struct stasis_topic *topic,
+	struct stasis_message *message)
+{
+	struct stasis_endpoint *endpoint = data;
+
+	if (stasis_subscription_final_message(sub, message)) {
+		ao2_cleanup(endpoint);
+	}
+}
+
+struct ast_endpoint *ast_endpoint_create(const char *tech, const char *resource)
+{
+	RAII_VAR(struct ast_endpoint *, endpoint, NULL, ao2_cleanup);
+	int r = 0;
+
+	if (ast_strlen_zero(tech)) {
+		ast_log(LOG_ERROR, "Endpoint tech cannot be empty\n");
+		return NULL;
+	}
+
+	if (ast_strlen_zero(resource)) {
+		ast_log(LOG_ERROR, "Endpoint resource cannot be empty\n");
+		return NULL;
+	}
+
+	endpoint = ao2_alloc(sizeof(*endpoint), endpoint_dtor);
+	if (!endpoint) {
+		return NULL;
+	}
+
+	endpoint->max_channels = -1;
+	endpoint->state = AST_ENDPOINT_UNKNOWN;
+
+	if (ast_string_field_init(endpoint, 80) != 0) {
+		return NULL;
+	}
+
+	ast_string_field_set(endpoint, tech, tech);
+	ast_string_field_set(endpoint, resource, resource);
+	ast_string_field_build(endpoint, id, "%s/%s", tech, resource);
+
+	/* All access to channel_ids should be covered by the endpoint's
+	 * lock; no extra lock needed. */
+	endpoint->channel_ids = ast_str_container_alloc_options(
+		AO2_ALLOC_OPT_LOCK_NOLOCK, ENDPOINT_BUCKETS);
+	if (!endpoint->channel_ids) {
+		return NULL;
+	}
+
+	endpoint->topic = stasis_topic_create(endpoint->id);
+	if (!endpoint->topic) {
+		return NULL;
+	}
+
+	endpoint->forward =
+		stasis_forward_all(endpoint->topic, ast_endpoint_topic_all());
+	if (!endpoint->forward) {
+		return NULL;
+	}
+
+	endpoint->router = stasis_message_router_create(endpoint->topic);
+	if (!endpoint->router) {
+		return NULL;
+	}
+	r |= stasis_message_router_add(endpoint->router,
+		ast_channel_snapshot_type(), endpoint_channel_snapshot,
+		endpoint);
+	r |= stasis_message_router_add(endpoint->router,
+		stasis_cache_clear_type(), endpoint_cache_clear,
+		endpoint);
+	r |= stasis_message_router_set_default(endpoint->router,
+		endpoint_default, endpoint);
+
+	endpoint_publish_snapshot(endpoint);
+
+	ao2_ref(endpoint, +1);
+	return endpoint;
+}
+
+const char *ast_endpoint_get_tech(const struct ast_endpoint *endpoint)
+{
+	ast_assert(endpoint != NULL);
+	return endpoint->tech;
+}
+
+void ast_endpoint_shutdown(struct ast_endpoint *endpoint)
+{
+	RAII_VAR(struct stasis_message *, message, NULL, ao2_cleanup);
+
+	if (endpoint == NULL) {
+		return;
+	}
+
+	message = stasis_cache_clear_create(ast_endpoint_snapshot_type(), endpoint->id);
+	if (message) {
+		stasis_publish(endpoint->topic, message);
+	}
+
+	stasis_message_router_unsubscribe(endpoint->router);
+	endpoint->router = NULL;
+}
+
+const char *ast_endpoint_get_resource(const struct ast_endpoint *endpoint)
+{
+	return endpoint->resource;
+}
+
+struct stasis_topic *ast_endpoint_topic(struct ast_endpoint *endpoint)
+{
+	return endpoint ? endpoint->topic : ast_endpoint_topic_all();
+}
+
+void ast_endpoint_set_state(struct ast_endpoint *endpoint,
+	enum ast_endpoint_state state)
+{
+	ast_assert(endpoint != NULL);
+	ao2_lock(endpoint);
+	endpoint->state = state;
+	ao2_unlock(endpoint);
+	endpoint_publish_snapshot(endpoint);
+}
+
+void ast_endpoint_set_max_channels(struct ast_endpoint *endpoint,
+	int max_channels)
+{
+	ast_assert(endpoint != NULL);
+	ao2_lock(endpoint);
+	endpoint->max_channels = max_channels;
+	ao2_unlock(endpoint);
+	endpoint_publish_snapshot(endpoint);
+}
+
+static void endpoint_snapshot_dtor(void *obj)
+{
+	struct ast_endpoint_snapshot *snapshot = obj;
+
+	ast_assert(snapshot != NULL);
+	ast_string_field_free_memory(snapshot);
+}
+
+struct ast_endpoint_snapshot *ast_endpoint_snapshot_create(
+	struct ast_endpoint *endpoint)
+{
+	RAII_VAR(struct ast_endpoint_snapshot *, snapshot, NULL, ao2_cleanup);
+	int channel_count;
+	struct ao2_iterator i;
+	void *obj;
+	SCOPED_AO2LOCK(lock, endpoint);
+
+	channel_count = ao2_container_count(endpoint->channel_ids);
+
+	snapshot = ao2_alloc(
+		sizeof(*snapshot) + channel_count * sizeof(char *),
+		endpoint_snapshot_dtor);
+
+	if (ast_string_field_init(snapshot, 80) != 0) {
+		return NULL;
+	}
+
+	ast_string_field_build(snapshot, id, "%s/%s", endpoint->tech,
+		endpoint->resource);
+	ast_string_field_set(snapshot, tech, endpoint->tech);
+	ast_string_field_set(snapshot, resource, endpoint->resource);
+
+	snapshot->state = endpoint->state;
+	snapshot->max_channels = endpoint->max_channels;
+
+	i = ao2_iterator_init(endpoint->channel_ids, 0);
+	while ((obj = ao2_iterator_next(&i))) {
+		RAII_VAR(char *, channel_id, obj, ao2_cleanup);
+		snapshot->channel_ids[snapshot->num_channels++] = channel_id;
+	}
+
+	ao2_ref(snapshot, +1);
+	return snapshot;
+}
diff --git a/main/stasis_cache.c b/main/stasis_cache.c
index 7b6dc82c9..6d07dc3c5 100644
--- a/main/stasis_cache.c
+++ b/main/stasis_cache.c
@@ -240,54 +240,45 @@ struct ao2_container *stasis_cache_dump(struct stasis_caching_topic *caching_top
 	return cache_dump.cached;
 }
 
-static struct stasis_message_type *__cache_clear_data;
+static struct stasis_message_type *cache_clear_type;
 
-static struct stasis_message_type *cache_clear_data(void)
+struct stasis_message_type *stasis_cache_clear_type(void)
 {
-	ast_assert(__cache_clear_data != NULL);
-	return __cache_clear_data;
+	ast_assert(cache_clear_type != NULL);
+	return cache_clear_type;
 }
 
-static struct stasis_message_type *__cache_update;
+static struct stasis_message_type *cache_update_type;
 
 struct stasis_message_type *stasis_cache_update_type(void)
 {
-	ast_assert(__cache_update != NULL);
-	return __cache_update;
+	ast_assert(cache_update_type != NULL);
+	return cache_update_type;
 }
 
-struct cache_clear_data {
-	struct stasis_message_type *type;
-	char *id;
-};
-
-static void cache_clear_data_dtor(void *obj)
+static void cache_clear_dtor(void *obj)
 {
-	struct cache_clear_data *ev = obj;
-	ast_free(ev->id);
-	ev->id = NULL;
+	struct stasis_cache_clear *ev = obj;
 	ao2_cleanup(ev->type);
 	ev->type = NULL;
 }
 
 struct stasis_message *stasis_cache_clear_create(struct stasis_message_type *type, const char *id)
 {
-	RAII_VAR(struct cache_clear_data *, ev, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_cache_clear *, ev, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
 
-	ev = ao2_alloc(sizeof(*ev), cache_clear_data_dtor);
+	ev = ao2_alloc(sizeof(*ev) + strlen(id) + 1, cache_clear_dtor);
 	if (!ev) {
 		return NULL;
 	}
 
-	ev->id = ast_strdup(id);
-	if (!ev->id) {
-		return NULL;
-	}
+	/* strcpy safe */
+	strcpy(ev->id, id);
 	ao2_ref(type, +1);
 	ev->type = type;
 
-	msg = stasis_message_create(cache_clear_data(), ev);
+	msg = stasis_message_create(stasis_cache_clear_type(), ev);
 
 	if (!msg) {
 		return NULL;
@@ -363,10 +354,10 @@ static void caching_topic_exec(void *data, struct stasis_subscription *sub, stru
 	}
 
 	/* Handle cache clear event */
-	if (cache_clear_data() == stasis_message_type(message)) {
+	if (stasis_cache_clear_type() == stasis_message_type(message)) {
 		RAII_VAR(struct stasis_message *, old_snapshot, NULL, ao2_cleanup);
 		RAII_VAR(struct stasis_message *, update, NULL, ao2_cleanup);
-		struct cache_clear_data *clear = stasis_message_data(message);
+		struct stasis_cache_clear *clear = stasis_message_data(message);
 		ast_assert(clear->type != NULL);
 		ast_assert(clear->id != NULL);
 		old_snapshot = cache_put(caching_topic, clear->type, clear->id, NULL);
@@ -374,7 +365,9 @@ static void caching_topic_exec(void *data, struct stasis_subscription *sub, stru
 			update = update_create(topic, old_snapshot, NULL);
 			stasis_publish(caching_topic->topic, update);
 		} else {
-			ast_log(LOG_ERROR,
+			/* While this could be a problem, it's very likely to
+			 * happen with message forwarding */
+			ast_debug(1,
 				"Attempting to remove an item from the cache that isn't there: %s %s\n",
 				stasis_message_type_name(clear->type), clear->id);
 		}
@@ -449,28 +442,28 @@ struct stasis_caching_topic *stasis_caching_topic_create(struct stasis_topic *or
 
 static void stasis_cache_exit(void)
 {
-	ao2_cleanup(__cache_clear_data);
-	__cache_clear_data = NULL;
-	ao2_cleanup(__cache_update);
-	__cache_update = NULL;
+	ao2_cleanup(cache_clear_type);
+	cache_clear_type = NULL;
+	ao2_cleanup(cache_update_type);
+	cache_update_type = NULL;
 }
 
 int stasis_cache_init(void)
 {
 	ast_register_atexit(stasis_cache_exit);
 
-	if (__cache_clear_data || __cache_update) {
+	if (cache_clear_type || cache_update_type) {
 		ast_log(LOG_ERROR, "Stasis cache double initialized\n");
 		return -1;
 	}
 
-	__cache_update = stasis_message_type_create("stasis_cache_update");
-	if (!__cache_update) {
+	cache_update_type = stasis_message_type_create("stasis_cache_update");
+	if (!cache_update_type) {
 		return -1;
 	}
 
-	__cache_clear_data = stasis_message_type_create("StasisCacheClear");
-	if (!__cache_clear_data) {
+	cache_clear_type = stasis_message_type_create("StasisCacheClear");
+	if (!cache_clear_type) {
 		return -1;
 	}
 	return 0;
diff --git a/main/stasis_endpoints.c b/main/stasis_endpoints.c
new file mode 100644
index 000000000..424df66c5
--- /dev/null
+++ b/main/stasis_endpoints.c
@@ -0,0 +1,189 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@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 endpoint API.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ */
+
+/*** MODULEINFO
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/astobj2.h"
+#include "asterisk/stasis.h"
+#include "asterisk/stasis_endpoints.h"
+
+static struct stasis_message_type *endpoint_snapshot_type;
+
+static struct stasis_topic *endpoint_topic_all;
+
+static struct stasis_caching_topic *endpoint_topic_all_cached;
+
+struct stasis_message_type *ast_endpoint_snapshot_type(void)
+{
+	return endpoint_snapshot_type;
+}
+
+struct stasis_topic *ast_endpoint_topic_all(void)
+{
+	return endpoint_topic_all;
+}
+
+struct stasis_caching_topic *ast_endpoint_topic_all_cached(void)
+{
+	return endpoint_topic_all_cached;
+}
+
+struct ast_endpoint_snapshot *ast_endpoint_latest_snapshot(const char *tech,
+	const char *name)
+{
+	RAII_VAR(char *, id, NULL, ast_free);
+	RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
+	struct ast_endpoint_snapshot *snapshot;
+
+	ast_asprintf(&id, "%s/%s", tech, name);
+	if (!id) {
+		return NULL;
+	}
+
+	msg = stasis_cache_get(ast_endpoint_topic_all_cached(),
+		ast_endpoint_snapshot_type(), id);
+	if (!msg) {
+		return NULL;
+	}
+
+	snapshot = stasis_message_data(msg);
+	ast_assert(snapshot != NULL);
+
+	ao2_ref(snapshot, +1);
+	return snapshot;
+}
+
+/*!
+ * \brief Callback extract a unique identity from a snapshot message.
+ *
+ * This identity is unique to the underlying object of the snapshot, such as the
+ * UniqueId field of a channel.
+ *
+ * \param message Message to extract id from.
+ * \return String representing the snapshot's id.
+ * \return \c NULL if the message_type of the message isn't a handled snapshot.
+ * \since 12
+ */
+static const char *endpoint_snapshot_get_id(struct stasis_message *message)
+{
+	struct ast_endpoint_snapshot *snapshot;
+
+	if (ast_endpoint_snapshot_type() != stasis_message_type(message)) {
+		return NULL;
+	}
+
+	snapshot = stasis_message_data(message);
+
+	return snapshot->id;
+}
+
+
+static void endpoints_stasis_shutdown(void)
+{
+	ao2_cleanup(endpoint_topic_all);
+	endpoint_topic_all = NULL;
+
+	stasis_caching_unsubscribe(endpoint_topic_all_cached);
+	endpoint_topic_all_cached = NULL;
+}
+
+struct ast_json *ast_endpoint_snapshot_to_json(
+	const struct ast_endpoint_snapshot *snapshot)
+{
+	RAII_VAR(struct ast_json *, json, NULL, ast_json_unref);
+	struct ast_json *channel_array;
+	int i;
+
+	json = ast_json_pack("{s: s, s: s, s: s, s: []}",
+		"technology", snapshot->tech,
+		"resource", snapshot->resource,
+		"state", ast_endpoint_state_to_string(snapshot->state),
+		"channels");
+
+	if (json == NULL) {
+		return NULL;
+	}
+
+	if (snapshot->max_channels != -1) {
+		int res = ast_json_object_set(json, "max_channels",
+			ast_json_integer_create(snapshot->max_channels));
+		if (res != 0) {
+			return NULL;
+		}
+	}
+
+	channel_array = ast_json_object_get(json, "channels");
+	ast_assert(channel_array != NULL);
+	for (i = 0; i < snapshot->num_channels; ++i) {
+		int res = ast_json_array_append(channel_array,
+			ast_json_stringf("channel:%s",
+				snapshot->channel_ids[i]));
+		if (res != 0) {
+			return NULL;
+		}
+	}
+
+	return ast_json_ref(json);
+}
+
+int ast_endpoint_stasis_init(void)
+{
+	ast_register_atexit(endpoints_stasis_shutdown);
+
+	if (!endpoint_topic_all) {
+		endpoint_topic_all = stasis_topic_create("endpoint_topic_all");
+	}
+
+	if (!endpoint_topic_all) {
+		return -1;
+	}
+
+	if (!endpoint_topic_all_cached) {
+		endpoint_topic_all_cached =
+			stasis_caching_topic_create(
+				endpoint_topic_all, endpoint_snapshot_get_id);
+	}
+
+	if (!endpoint_topic_all_cached) {
+		return -1;
+	}
+
+	if (!endpoint_snapshot_type) {
+		endpoint_snapshot_type = stasis_message_type_create(
+			"ast_endpoint_snapshot");
+	}
+
+	if (!endpoint_snapshot_type) {
+		return -1;
+	}
+
+	return 0;
+}