implement lifetime for broken hashes

diff --git a/src/mod_caps.erl b/src/mod_caps.erl
index 96233959243d33b53e2a7f2053bcd94f12aa8d95..15e6b5e7f0ab70a296bc1b0d78f7be5f78ed53d0 100644 (file)
--- a/src/mod_caps.erl
+++ b/src/mod_caps.erl
@@ -62,6 +62,7 @@
 -include("jlib.hrl").
 
 -define(PROCNAME, ejabberd_mod_caps).
+-define(BAD_HASH_LIFETIME, 600). %% in seconds
 
 -record(caps, {node, version, hash, exts}).
 -record(caps_features, {node_pair, features = []}).
@@ -104,10 +105,10 @@ get_features(#caps{node = Node, version = Version, exts = Exts}) ->
              BinaryNode = node_to_binary(Node, SubNode),
              case cache_tab:lookup(caps_features, BinaryNode,
                                    caps_read_fun(BinaryNode)) of
-                 error ->
-                     Acc;
-                 {ok, Features} ->
-                     binary_to_features(Features) ++ Acc
+                 {ok, Features} when is_list(Features) ->
+                     binary_to_features(Features) ++ Acc;
+                 _ ->
+                     Acc
              end
       end, [], SubNodes).
 
@@ -358,21 +359,31 @@ feature_request(Host, From, Caps, [SubNode | Tail] = SubNodes) ->
     BinaryNode = node_to_binary(Node, SubNode),
     case cache_tab:lookup(caps_features, BinaryNode,
                          caps_read_fun(BinaryNode)) of
-       error ->
-           IQ = #iq{type = get,
-                    xmlns = ?NS_DISCO_INFO,
-                    sub_el = [{xmlelement, "query",
-                               [{"xmlns", ?NS_DISCO_INFO},
-                                {"node", Node ++ "#" ++ SubNode}],
-                               []}]},
-           F = fun(IQReply) ->
-                       feature_response(
-                         IQReply, Host, From, Caps, SubNodes)
-               end,
-           ejabberd_local:route_iq(
-             jlib:make_jid("", Host, ""), From, IQ, F);
-       _ ->
-           feature_request(Host, From, Caps, Tail)
+       {ok, Fs} when is_list(Fs) ->
+           feature_request(Host, From, Caps, Tail);
+       Other ->
+           NeedRequest = case Other of
+                             {ok, TS} ->
+                                 now_ts() >= TS + ?BAD_HASH_LIFETIME;
+                             _ ->
+                                 true
+                         end,
+           if NeedRequest ->
+                   IQ = #iq{type = get,
+                            xmlns = ?NS_DISCO_INFO,
+                            sub_el = [{xmlelement, "query",
+                                       [{"xmlns", ?NS_DISCO_INFO},
+                                        {"node", Node ++ "#" ++ SubNode}],
+                                       []}]},
+                   F = fun(IQReply) ->
+                               feature_response(
+                                 IQReply, Host, From, Caps, SubNodes)
+                       end,
+                   ejabberd_local:route_iq(
+                     jlib:make_jid("", Host, ""), From, IQ, F);
+              true ->
+                   feature_request(Host, From, Caps, Tail)
+           end
     end;
 feature_request(_Host, _From, _Caps, []) ->
     ok.
@@ -394,18 +405,19 @@ feature_response(#iq{type = result,
              caps_features, BinaryNode, BinaryFeatures,
              caps_write_fun(BinaryNode, BinaryFeatures));
        false ->
-           cache_tab:insert(caps_features, BinaryNode, [],
-                            caps_write_fun(BinaryNode, []))
+           %% We cache current timestamp and will probe the client
+           %% after BAD_HASH_LIFETIME seconds.
+           cache_tab:insert(caps_features, BinaryNode, now_ts(),
+                            caps_write_fun(BinaryNode, now_ts()))
     end,
     feature_request(Host, From, Caps, SubNodes);
-feature_response(timeout, _Host, _From, _Caps, _SubNodes) ->
-    ok;
 feature_response(_IQResult, Host, From, Caps, [SubNode | SubNodes]) ->
-    %% We got type=error or invalid type=result stanza, so
-    %% we cache empty feature not to probe the client permanently
+    %% We got type=error or invalid type=result stanza or timeout,
+    %% so we cache current timestamp and will probe the client
+    %% after BAD_HASH_LIFETIME seconds.
     BinaryNode = node_to_binary(Caps#caps.node, SubNode),
-    cache_tab:insert(caps_features, BinaryNode, [],
-                    caps_write_fun(BinaryNode, [])),
+    cache_tab:insert(caps_features, BinaryNode, now_ts(),
+                    caps_write_fun(BinaryNode, now_ts())),
     feature_request(Host, From, Caps, SubNodes).
 
 node_to_binary(Node, SubNode) ->
@@ -611,3 +623,7 @@ gb_trees_fold_iter(F, Acc, Iter) ->
        _ ->
            Acc
     end.
+
+now_ts() ->
+    {MegaSecs, Secs, _} = now(),
+    MegaSecs*1000000 + Secs.