lightningd: don't listen at all if no port number set.

When we support the Milan protocol, we'll use a default port.  But
for now, don't listen at all unless a port is specified.

Fixes: #54
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

daemon/lightningd.c

@@ -487,7 +487,7 @@ int main(int argc, char *argv[])
 			   "A bitcoin lightning daemon.",
 			   "Print this message.");
 	opt_register_arg("--port", opt_set_uintval, NULL, &portnum,
-			 "Port to bind to (otherwise, dynamic port is used)");
+			 "Port to bind to (otherwise, we don't listen)");
 	opt_register_arg("--bitcoin-datadir", opt_set_charp, NULL,
 			 &bitcoin_datadir,
 			 "-datadir arg for bitcoin-cli");
@@ -543,6 +543,7 @@ int main(int argc, char *argv[])
 	setup_jsonrpc(dstate, dstate->rpc_filename);
 
 	/* Set up connections from peers. */
+	if (portnum != 0)
 		setup_listeners(dstate, portnum);
 
 	/* set up IRC peer discovery */

daemon/test/scripts/helpers.sh

@@ -117,12 +117,9 @@ EOF
     cp $DIR1/config $DIR2/config
     [ $NUM_LIGHTNINGD = 2 ] || cp $DIR1/config $DIR3/config
 
-    if [ x"$RECONNECT" = xrestart ]; then
-	# Make sure node2 & 3 restart on same port, by setting in config.
     # Find a free TCP port.
     echo port=`findport 4000 $VARIANT` >> $DIR2/config
     [ $NUM_LIGHTNINGD = 2 ] || echo port=`findport 4010 $VARIANT` >> $DIR3/config
-    fi
 }
 
 # Use DIR REDIR REDIRERR GDBFLAG