res_pjsip_mwi.c

	int is_first = 1;
	struct mwi_stasis_subscription *node;
	struct ao2_iterator i = ao2_iterator_init(stasis_subs, 0);

	while ((node = ao2_iterator_next(&i))) {
		if (is_first) {
			is_first = 0;
			ast_str_append(str, 0, "%s", node->mailbox);
		} else {
			ast_str_append(str, 0, ",%s", node->mailbox);
		}
		ao2_ref(node, -1);
	}
	ao2_iterator_destroy(&i);
}

static void mwi_to_ami(struct ast_sip_subscription *sub,
		       struct ast_str **buf)
{
	struct mwi_subscription *mwi_sub;
	struct ast_datastore *mwi_datastore;

	mwi_datastore = ast_sip_subscription_get_datastore(sub, MWI_DATASTORE);
	if (!mwi_datastore) {
		return;
	}

	mwi_sub = mwi_datastore->data;

	ast_str_append(buf, 0, "SubscriptionType: mwi\r\n");
	ast_str_append(buf, 0, "Mailboxes: ");
	mwi_subscription_mailboxes_str(mwi_sub->stasis_subs, buf);
	ast_str_append(buf, 0, "\r\n");

	ao2_ref(mwi_datastore, -1);
}

static int serialized_notify(void *userdata)
{
	struct mwi_subscription *mwi_sub = userdata;

	send_mwi_notify(mwi_sub);
	ao2_ref(mwi_sub, -1);
	return 0;
}

static int serialized_cleanup(void *userdata)
{
	struct mwi_subscription *mwi_sub = userdata;

	/* This is getting rid of the reference that was added
	 * just before this serialized task was pushed.
	 */
	ao2_cleanup(mwi_sub);
	/* This is getting rid of the reference held by the
	 * stasis subscription
	 */
	ao2_cleanup(mwi_sub);
	return 0;
}

static int send_notify(void *obj, void *arg, int flags)
{
	struct mwi_subscription *mwi_sub = obj;
	struct ast_taskprocessor *serializer = mwi_sub->is_solicited
		? ast_sip_subscription_get_serializer(mwi_sub->sip_sub)
		: get_mwi_serializer();

	if (ast_sip_push_task(serializer, serialized_notify, ao2_bump(mwi_sub))) {
		ao2_ref(mwi_sub, -1);
	}

	return 0;
}

static void mwi_stasis_cb(void *userdata, struct stasis_subscription *sub,
		struct stasis_message *msg)
{
	struct mwi_subscription *mwi_sub = userdata;

	if (stasis_subscription_final_message(sub, msg)) {
		if (ast_sip_push_task(NULL, serialized_cleanup, ao2_bump(mwi_sub))) {
			ao2_ref(mwi_sub, -1);
		}
		return;
	}

	if (ast_mwi_state_type() == stasis_message_type(msg)) {
		send_notify(mwi_sub, NULL, 0);
	}
}

/*! \note Called with the unsolicited_mwi container lock held. */
static int create_mwi_subscriptions_for_endpoint(void *obj, void *arg, int flags)
{
	RAII_VAR(struct mwi_subscription *, aggregate_sub, NULL, ao2_cleanup);
	struct ast_sip_endpoint *endpoint = obj;
	char *mailboxes, *mailbox;

	if (ast_strlen_zero(endpoint->subscription.mwi.mailboxes)) {
		return 0;
	}

	if (endpoint->subscription.mwi.aggregate) {
		aggregate_sub = mwi_subscription_alloc(endpoint, 0, NULL);
		if (!aggregate_sub) {
			return 0;
		}
	}

	mailboxes = ast_strdupa(endpoint->subscription.mwi.mailboxes);
	while ((mailbox = ast_strip(strsep(&mailboxes, ",")))) {
		struct mwi_subscription *sub;
		struct mwi_stasis_subscription *mwi_stasis_sub;

		if (ast_strlen_zero(mailbox)) {
			continue;
		}

		sub = aggregate_sub ?: mwi_subscription_alloc(endpoint, 0, NULL);
		mwi_stasis_sub = mwi_stasis_subscription_alloc(mailbox, sub);
		if (mwi_stasis_sub) {
			ao2_link(sub->stasis_subs, mwi_stasis_sub);
			ao2_ref(mwi_stasis_sub, -1);
		}
		if (!aggregate_sub && sub) {
			ao2_link_flags(unsolicited_mwi, sub, OBJ_NOLOCK);
			ao2_ref(sub, -1);
		}
	}
	if (aggregate_sub) {
		ao2_link_flags(unsolicited_mwi, aggregate_sub, OBJ_NOLOCK);
	}
	return 0;
}

static int unsubscribe(void *obj, void *arg, int flags)
{
	struct mwi_subscription *mwi_sub = obj;

	ao2_callback(mwi_sub->stasis_subs, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, unsubscribe_stasis, NULL);

	return CMP_MATCH;
}

static void create_mwi_subscriptions(void)
{
	struct ao2_container *endpoints;
	struct ast_variable *var;

	var = ast_variable_new("mailboxes !=", "", "");

	endpoints = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "endpoint",
		AST_RETRIEVE_FLAG_MULTIPLE, var);

	ast_variables_destroy(var);
	if (!endpoints) {
		return;
	}

	/* We remove all the old stasis subscriptions first before applying the new configuration. This
	 * prevents a situation where there might be multiple overlapping stasis subscriptions for an
	 * endpoint for mailboxes. Though there may be mailbox changes during the gap between unsubscribing
	 * and resubscribing, up-to-date mailbox state will be sent out to the endpoint when the
	 * new stasis subscription is established
	 */
	ao2_lock(unsolicited_mwi);
	ao2_callback(unsolicited_mwi, OBJ_NOLOCK | OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, unsubscribe, NULL);
	ao2_callback(endpoints, OBJ_NODATA, create_mwi_subscriptions_for_endpoint, NULL);
	ao2_unlock(unsolicited_mwi);

	ao2_ref(endpoints, -1);
}

/*! \brief Function called to send MWI NOTIFY on any unsolicited mailboxes relating to this AOR */
static int send_contact_notify(void *obj, void *arg, int flags)
{
	struct mwi_subscription *mwi_sub = obj;
	const char *aor = arg;

	if (!mwi_sub->aors || !strstr(mwi_sub->aors, aor)) {
		return 0;
	}

	if (ast_sip_push_task(get_mwi_serializer(), serialized_notify, ao2_bump(mwi_sub))) {
		ao2_ref(mwi_sub, -1);
	}

	return 0;
}

/*! \brief Function called when a contact is updated */
static void mwi_contact_updated(const void *object)
{
	char *id = ast_strdupa(ast_sorcery_object_get_id(object)), *aor = NULL;

	aor = strsep(&id, ";@");

	ao2_callback(unsolicited_mwi, OBJ_NODATA, send_contact_notify, aor);
}

/*! \brief Function called when a contact is added */
static void mwi_contact_added(const void *object)
{
	const struct ast_sip_contact *contact = object;
	struct ao2_iterator *mwi_subs;
	struct mwi_subscription *mwi_sub;
	const char *endpoint_id = ast_sorcery_object_get_id(contact->endpoint);

	if (ast_strlen_zero(contact->endpoint->subscription.mwi.mailboxes)) {
		return;
	}

	ao2_lock(unsolicited_mwi);

	mwi_subs = ao2_find(unsolicited_mwi, endpoint_id,
		OBJ_SEARCH_KEY | OBJ_MULTIPLE | OBJ_NOLOCK | OBJ_UNLINK);
	if (mwi_subs) {
		for (; (mwi_sub = ao2_iterator_next(mwi_subs)); ao2_cleanup(mwi_sub)) {
			unsubscribe(mwi_sub, NULL, 0);
		}
		ao2_iterator_destroy(mwi_subs);
	}

	create_mwi_subscriptions_for_endpoint(contact->endpoint, NULL, 0);

	ao2_unlock(unsolicited_mwi);

	mwi_contact_updated(object);
}

/*! \brief Observer for contacts so unsolicited MWI is sent when a contact changes */
static const struct ast_sorcery_observer mwi_contact_observer = {
	.created = mwi_contact_added,
	.updated = mwi_contact_updated,
};

/*! \brief Task invoked to send initial MWI NOTIFY for unsolicited */
static int send_initial_notify_all(void *obj)
{
	ao2_callback(unsolicited_mwi, OBJ_NODATA, send_notify, NULL);

	return 0;
}

/*! \brief Event callback which fires initial unsolicited MWI NOTIFY messages when we're fully booted */
static void mwi_startup_event_cb(void *data, struct stasis_subscription *sub, struct stasis_message *message)
{
	struct ast_json_payload *payload;
	const char *type;

	if (stasis_message_type(message) != ast_manager_get_generic_type()) {
		return;
	}

	payload = stasis_message_data(message);
	type = ast_json_string_get(ast_json_object_get(payload->json, "type"));

	if (strcmp(type, "FullyBooted")) {
		return;
	}

	ast_sip_push_task(NULL, send_initial_notify_all, NULL);

	stasis_unsubscribe(sub);
}

static void global_loaded(const char *object_type)
{
	ast_free(default_voicemail_extension);
	default_voicemail_extension = ast_sip_get_default_voicemail_extension();
	mwi_serializer_set_alert_levels();
}

static struct ast_sorcery_observer global_observer = {
	.loaded = global_loaded,
};

static int reload(void)
{
	if (!ast_sip_get_mwi_disable_initial_unsolicited()) {
		create_mwi_subscriptions();
	}
	return 0;
}

static int load_module(void)
{
	CHECK_PJSIP_MODULE_LOADED();

	if (ast_sip_register_subscription_handler(&mwi_handler)) {
		return AST_MODULE_LOAD_DECLINE;
	}

	if (mwi_serializer_pool_setup()) {
		ast_log(AST_LOG_WARNING, "Failed to create MWI serializer pool. The default SIP pool will be used for MWI\n");
	}

	unsolicited_mwi = ao2_container_alloc_hash(AO2_ALLOC_OPT_LOCK_MUTEX, 0, MWI_BUCKETS,
		mwi_sub_hash, NULL, mwi_sub_cmp);
	if (!unsolicited_mwi) {
		mwi_serializer_pool_shutdown();
		ast_sip_unregister_subscription_handler(&mwi_handler);
		return AST_MODULE_LOAD_DECLINE;
	}

	ast_sorcery_observer_add(ast_sip_get_sorcery(), "contact", &mwi_contact_observer);
	ast_sorcery_observer_add(ast_sip_get_sorcery(), "global", &global_observer);
	ast_sorcery_reload_object(ast_sip_get_sorcery(), "global");

	if (!ast_sip_get_mwi_disable_initial_unsolicited()) {
		create_mwi_subscriptions();
		if (ast_test_flag(&ast_options, AST_OPT_FLAG_FULLY_BOOTED)) {
			ast_sip_push_task(NULL, send_initial_notify_all, NULL);
		} else {
			stasis_subscribe_pool(ast_manager_get_topic(), mwi_startup_event_cb, NULL);
		}
	}

	return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
	ast_sorcery_observer_remove(ast_sip_get_sorcery(), "global", &global_observer);
	ast_sorcery_observer_remove(ast_sip_get_sorcery(), "contact", &mwi_contact_observer);

	ao2_callback(unsolicited_mwi, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, unsubscribe, NULL);
	ao2_ref(unsolicited_mwi, -1);
	unsolicited_mwi = NULL;

	mwi_serializer_pool_shutdown();

	ast_sip_unregister_subscription_handler(&mwi_handler);

	ast_free(default_voicemail_extension);
	default_voicemail_extension = NULL;
	return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP MWI resource",
	.support_level = AST_MODULE_SUPPORT_CORE,
	.load = load_module,
	.unload = unload_module,
	.reload = reload,
	.load_pri = AST_MODPRI_CHANNEL_DEPEND + 5,
);