options: Add `--offline` to disable listening and auto-reconnection

gossipd/gossip.c

@@ -1502,7 +1502,10 @@ static struct io_plan *gossip_init(struct daemon_conn *master,
 	}
 	daemon->rstate = new_routing_state(daemon, &chain_hash, &daemon->id);
 
-	setup_listeners(daemon, port);
+	if (port)
+		setup_listeners(daemon, port);
+	else
+		status_trace("Not listeing for incoming connections due to --no-listen");
 
 	new_reltimer(&daemon->timers, daemon,
 		     time_from_sec(daemon->update_channel_interval/2),

lightningd/lightningd.h

@@ -148,6 +148,9 @@ struct lightningd {
 	/* May be useful for non-developers debugging in the field */
 	char *debug_subdaemon_io;
 
+	/* Disable automatic reconnects */
+	bool no_reconnect;
+
 #if DEVELOPER
 	/* If we want to debug a subdaemon. */
 	const char *dev_debug_subdaemon;
@@ -163,9 +166,6 @@ struct lightningd {
 
 	/* Things we've marked as not leaking. */
 	const void **notleaks;
-
-	/* Disable automatic reconnects */
-	bool no_reconnect;
 #endif /* DEVELOPER */
 };
 

lightningd/options.c

@@ -210,6 +210,13 @@ static char *opt_set_fee_rates(const char *arg, struct chain_topology *topo)
 	return NULL;
 }
 
+static char *opt_set_offline(struct lightningd *ld)
+{
+	ld->portnum = 0;
+	ld->no_reconnect = true;
+	return NULL;
+}
+
 static void config_register_opts(struct lightningd *ld)
 {
 	opt_register_noarg("--daemon", opt_set_bool, &ld->daemon,
@@ -271,6 +278,8 @@ static void config_register_opts(struct lightningd *ld)
 	opt_register_arg("--ipaddr", opt_add_ipaddr, NULL,
 			 ld,
 			 "Set the IP address (v4 or v6) to announce to the network for incoming connections");
+	opt_register_noarg("--offline", opt_set_offline, ld,
+			   "Start in offline-mode (do not automatically reconnect and do not accept incoming connections");
 
 	opt_register_early_arg("--network", opt_set_network, opt_show_network,
 			       ld,
@@ -719,6 +728,7 @@ static void add_config(struct lightningd *ld,
 	if (opt->type & OPT_NOARG) {
 		if (opt->cb == (void *)opt_usage_and_exit
 		    || opt->cb == (void *)version_and_exit
+		    || opt->cb == (void *)opt_set_offline /* will show up as port=0 and --no-reconnect */
 		    || opt->cb == (void *)test_daemons_and_exit) {
 			/* These are not important */
 		} else if (opt->cb == (void *)opt_set_bool) {
@@ -855,4 +865,3 @@ static const struct json_command listconfigs_command = {
 	"With [config], object only has that field"
 };
 AUTODATA(json_command, &listconfigs_command);
-