feat: add hook for sending packet from component

New hook 'component_send_packet' added.
Callback function must accept one argument {Pkt, ComponentState} and should yield 'drop' or {NewPkt, NewComponentState}.

src/ejabberd_service.erl

@@ -185,14 +185,20 @@ handle_auth_failure(_, Mech, Reason,
 	       Reason]),
     State.
 
-handle_authenticated_packet(Pkt0, #{ip := {IP, _}, lang := Lang} = State)
+handle_authenticated_packet(Pkt0, #{server := Server, ip := {IP, _}, lang := Lang} = State)
   when ?is_stanza(Pkt0) ->
     Pkt = xmpp:put_meta(Pkt0, ip, IP),
     From = xmpp:get_from(Pkt),
     case check_from(From, State) of
 	true ->
-	    ejabberd_router:route(Pkt),
-	    State;
+        {Pkt2, State2} = ejabberd_hooks:run_fold(component_send_packet, Server, {Pkt, State}, []),
+        case Pkt2 of
+            drop ->
+                ok;
+            _ ->
+                ejabberd_router:route(Pkt2)
+		end,
+        State2;
 	false ->
 	    Txt = <<"Improper domain part of 'from' attribute">>,
 	    Err = xmpp:serr_invalid_from(Txt, Lang),