Before binding tcp ports, checks the socket type and listener options

(EJAB-1334)

If the callback module has a socket type of independent and needs to
create the listener itself, do not pre-bind the port. The same holds if
there are errors in the listener configuration.

src/ejabberd_listener.erl

@@ -60,11 +60,18 @@ bind_tcp_ports() ->
 	Ls ->
 	    lists:foreach(
 	      fun({Port, Module, Opts}) ->
+		      ModuleRaw = strip_frontend(Module),
+		      case ModuleRaw:socket_type() of
+			  independent -> ok;
+			  _ ->
 			      bind_tcp_port(Port, Module, Opts)
+		      end
 	      end, Ls)
     end.
 
 bind_tcp_port(PortIP, Module, RawOpts) ->
+    try check_listener_options(RawOpts) of
+	ok ->
 	    {Port, IPT, IPS, IPV, Proto, OptsClean} = parse_listener_portip(PortIP, RawOpts),
 	    {_Opts, SockOpts} = prepare_opts(IPT, IPV, OptsClean),
 	    case Proto of
@@ -72,6 +79,10 @@ bind_tcp_port(PortIP, Module, RawOpts) ->
 		_ ->
 		    ListenSocket = listen_tcp(PortIP, Module, SockOpts, Port, IPS),
 		    ets:insert(listen_sockets, {PortIP, ListenSocket})
+	    end
+    catch
+	throw:{error, Error} ->
+	    ?ERROR_MSG(Error, [])
     end.
 
 start_listeners() ->