Speed up ejabberd_s2s:is_service/2, allow_host/2 (thanks to Andreas Köhler)(EJAB...

Iterating through the list of possible parent domains of a given domain
and comparing with the list of hosts or routes is almost always faster
than doing it the other way around. It naturally returns the shortest or
longest parent domain satisfying a predicate, whereas the possibly long
list compared with would need to be sorted by length first.

diff --git a/src/ejabberd_s2s.erl b/src/ejabberd_s2s.erl
index 8ab520f56e59f93d2d8308e5f04c03291466e97b..4d32ef66d29d594e98f50e4197275c10e5925943 100644 (file)
--- a/src/ejabberd_s2s.erl
+++ b/src/ejabberd_s2s.erl
@@ -408,22 +408,21 @@ needed_connections_number(Ls, MaxS2SConnectionsNumber,
 is_service(From, To) ->
     LFromDomain = From#jid.lserver,
     case ejabberd_config:get_local_option({route_subdomains, LFromDomain}) of
-        s2s -> % bypass RFC 3920 10.3
-            false;
-        _ ->
-            LDstDomain = To#jid.lserver,
-            P = fun(Domain) -> is_subdomain(LDstDomain, Domain) end,
-            lists:any(P, ?MYHOSTS)
+       s2s -> % bypass RFC 3920 10.3
+           false;
+       _ ->
+           Hosts = ?MYHOSTS,
+           P = fun(ParentDomain) -> lists:member(ParentDomain, Hosts) end,
+           lists:any(P, parent_domains(To#jid.lserver))
     end.
 
-%%--------------------------------------------------------------------
-%% Function: is_subdomain(Domain1, Domain2) -> true | false
-%% Description: Return true if Domain1 (a string representing an
-%% internet domain name) is a subdomain (or the same domain) of
-%% Domain2
-%% --------------------------------------------------------------------
-is_subdomain(Domain1, Domain2) ->
-    lists:suffix(string:tokens(Domain2, "."), string:tokens(Domain1, ".")).
+parent_domains(Domain) ->
+    lists:foldl(
+      fun(Label, []) ->
+             [Label];
+        (Label, [Head | Tail]) ->
+             [Label ++ "." ++ Head, Head | Tail]
+      end, [], lists:reverse(string:tokens(Domain, "."))).
 
 send_element(Pid, El) ->
     Pid ! {send_element, El}.
@@ -486,10 +485,11 @@ update_tables() ->
 
 %% Check if host is in blacklist or white list
 allow_host(MyServer, S2SHost) ->
-    case lists:filter(
-          fun(Host) ->
-                  is_subdomain(MyServer, Host)
-          end, ?MYHOSTS) of
+    Hosts = ?MYHOSTS,
+    case lists:dropwhile(
+          fun(ParentDomain) ->
+                  not lists:member(ParentDomain, Hosts)
+          end, parent_domains(MyServer)) of
        [MyHost|_] ->
            allow_host1(MyHost, S2SHost);
        [] ->