Remove Cluster::broadcast_topic

As enabling Broker forwarding would cause routing loops with messages
sent to such a topic (one subscribed to on all nodes).

doc/frameworks/broker.rst

@@ -271,9 +271,9 @@ communication flows unrelated to Bro cluster, new topics are declared
 
 For cluster operation, see :doc:`/scripts/base/frameworks/cluster/main.bro`
 for a list of topics that are useful for steering published events to
-the various node classes.  E.g. you have the ability to broadcast to all
+the various node classes.  E.g. you have the ability to broadcast
-directly-connected nodes, only those of a given class (e.g. just workers),
+to all nodes of a given class (e.g. just workers) or just send to a
-or to a specific node within a class.
+specific node within a class.
 
 The topic names that logs get published under are a bit nuanced.  In the
 default cluster configuration, they are round-robin published to

scripts/base/frameworks/cluster/main.bro

@@ -15,10 +15,6 @@ export {
 	## Whether to distribute log messages among available logging nodes.
 	const enable_round_robin_logging = T &redef;
 
-	## The topic name used for exchanging general messages that are relevant to
-	## any node in a cluster.  Used with broker-enabled cluster communication.
-	const broadcast_topic = "bro/cluster/broadcast" &redef;
-
 	## The topic name used for exchanging messages that are relevant to
 	## logger nodes in a cluster.  Used with broker-enabled cluster communication.
 	const logger_topic = "bro/cluster/logger" &redef;
@@ -43,6 +39,10 @@ export {
 	## a named node in a cluster.  Used with broker-enabled cluster communication.
 	const node_topic_prefix = "bro/cluster/node/" &redef;
 
+	## The topic prefix used for exchanging messages that are relevant to
+	## a unique node in a cluster.  Used with broker-enabled cluster communication.
+	const nodeid_topic_prefix = "bro/cluster/nodeid/" &redef;
+
 	## Name of the node on which master data stores will be created if no other
 	## has already been specified by the user in :bro:see:`Cluster::stores`.
 	## An empty value means "use whatever name corresponds to the manager
@@ -238,6 +238,15 @@ export {
 	## Returns: a topic string that may used to send a message exclusively to
 	##          a given cluster node.
 	global node_topic: function(name: string): string;
+
+	## Retrieve the topic associated with a specific node in the cluster.
+	##
+	## id: the id of the cluster node (from :bro:see:`Broker::EndpointInfo`
+	##     or :bro:see:`Broker::node_id`.
+	##
+	## Returns: a topic string that may used to send a message exclusively to
+	##          a given cluster node.
+	global nodeid_topic: function(id: string): string;
 }
 
 global active_worker_ids: set[string] = set();
@@ -286,6 +295,11 @@ function node_topic(name: string): string
 	return node_topic_prefix + name;
 	}
 
+function nodeid_topic(id: string): string
+	{
+	return node_topic_prefix + id;
+	}
+
 event Cluster::hello(name: string, id: string) &priority=10
 	{
 	if ( name !in nodes )
@@ -321,7 +335,7 @@ event Broker::peer_added(endpoint: Broker::EndpointInfo, msg: string) &priority=
 		return;
 
 	local e = Broker::make_event(Cluster::hello, node, Broker::node_id());
-	Broker::publish(Cluster::broadcast_topic, e);
+	Broker::publish(nodeid_topic(endpoint$id), e);
 	}
 
 event Broker::peer_lost(endpoint: Broker::EndpointInfo, msg: string) &priority=10

scripts/base/frameworks/cluster/setup-connections.bro

@@ -87,7 +87,7 @@ event bro_init() &priority=-10
 		return;
 	}
 
-	Broker::subscribe(Cluster::broadcast_topic);
+	Broker::subscribe(nodeid_topic(Broker::node_id()));
 	Broker::subscribe(node_topic(node));
 
 	Broker::listen(Broker::default_listen_address,

scripts/base/frameworks/config/main.bro

@@ -52,12 +52,25 @@ type OptionCacheValue: record {
 
 global option_cache: table[string] of OptionCacheValue;
 
+global Config::cluster_set_option: event(ID: string, val: any, location: string);
+
+function broadcast_option(ID: string, val: any, location: string)
+	{
+	# There's not currently a common topic to broadcast to as then enabling
+	# implicit Broker forwarding would cause a routing loop.
+	Broker::publish(Cluster::worker_topic, Config::cluster_set_option,
+	                ID, val, location);
+	Broker::publish(Cluster::proxy_topic, Config::cluster_set_option,
+	                ID, val, location);
+	Broker::publish(Cluster::logger_topic, Config::cluster_set_option,
+	                ID, val, location);
+	}
+
 event Config::cluster_set_option(ID: string, val: any, location: string)
 	{
 @if ( Cluster::local_node_type() == Cluster::MANAGER )
 	option_cache[ID] = OptionCacheValue($val=val, $location=location);
-	Broker::publish(Cluster::broadcast_topic, Config::cluster_set_option,
+	broadcast_option(ID, val, location);
-	                ID, val, location);
 @endif
 
 	Option::set(ID, val, location);
@@ -77,8 +90,7 @@ function set_value(ID: string, val: any, location: string &default = "" &optiona
 
 @if ( Cluster::local_node_type() == Cluster::MANAGER )
 	option_cache[ID] = OptionCacheValue($val=val, $location=location);
-	Broker::publish(Cluster::broadcast_topic, Config::cluster_set_option,
+	broadcast_option(ID, val, location);
-	                ID, val, location);
 @else
 	Broker::publish(Cluster::manager_topic, Config::cluster_set_option,
 	                ID, val, location);