ejabberd_sm: Fix routing of headline messages

As per RFC 6121, silently drop headline messages sent to the bare JID of
an offline user or to the full JID of an unavailable resource.

src/ejabberd_sm.erl

@@ -177,7 +177,8 @@ check_in_subscription(Acc, User, Server, _JID, _Type, _Reason) ->
 
 -spec bounce_offline_message({bounce, message()} | any()) -> any().
 
-bounce_offline_message({bounce, Packet} = Acc) ->
+bounce_offline_message({bounce, #message{type = T} = Packet} = Acc)
+    when T == chat; T == groupchat; T == normal ->
     Lang = xmpp:get_lang(Packet),
     Txt = <<"User session not found">>,
     Err = xmpp:err_service_unavailable(Txt, Lang),
@@ -572,9 +573,11 @@ do_route(Packet) ->
     case online(Mod:get_sessions(LUser, LServer, LResource)) of
 	[] ->
 	    case Packet of
-		#message{type = T} when T == chat; T == normal;
-					T == headline ->
+		#message{type = T} when T == chat; T == normal ->
 		    route_message(Packet);
+		#message{type = T} when T == headline ->
+		    ?DEBUG("dropping headline to unavailable resource:~n~s",
+			   [xmpp:pp(Packet)]);
 		#presence{} ->
 		    ?DEBUG("dropping presence to unavailable resource:~n~s",
 			   [xmpp:pp(Packet)]);

test/offline_tests.erl

@@ -197,7 +197,9 @@ send_all_master(Config) ->
     		  Acc + 1
     	  end, 0, Deliver),
     lists:foreach(
-      fun(Msg) ->
+      fun(#message{type = headline} = Msg) ->
+	      send(Config, Msg#message{to = BarePeer});
+         (Msg) ->
 	      #message{type = error} = Err =
 		  send_recv(Config, Msg#message{to = BarePeer}),
 	      #stanza_error{reason = 'service-unavailable'} = xmpp:get_error(Err)