Merge branch 'anders/diameter/overload/OTP-13330'

* anders/diameter/overload/OTP-13330:
  Suppress dialyzer warning
  Remove dead case clause
  Let throttling callback send a throttle message
  Acknowledge answers to notification pids when throttling
  Throttle properly with TLS
  Don't ask throttling callback to receive more unless needed
  Let a throttling callback answer a received message
  Let a throttling callback discard a received message
  Let throttling callback return a notification pid
  Make throttling callbacks on message reception
  Add diameter_tcp option throttle_cb

1 files changed, 20 insertions, 10 deletions

diff --git a/lib/diameter/src/base/diameter_traffic.erl b/lib/diameter/src/base/diameter_traffic.erl
index c169d3fc2c..2112941d5e 100644
--- a/lib/diameter/src/base/diameter_traffic.erl
+++ b/lib/diameter/src/base/diameter_traffic.erl
@@ -230,7 +230,15 @@ pending(TPids) ->
 %% used to come through the service process but this avoids that
 %% becoming a bottleneck.
 
-receive_message(TPid, Pkt, Dict0, RecvData)
+receive_message(TPid, {Pkt, NPid}, Dict0, RecvData) ->
+    NPid ! {diameter, incoming(TPid, Pkt, Dict0, RecvData)};
+
+receive_message(TPid, Pkt, Dict0, RecvData) ->
+    incoming(TPid, Pkt, Dict0, RecvData).
+
+%% incoming/4
+
+incoming(TPid, Pkt, Dict0, RecvData)
   when is_pid(TPid) ->
     #diameter_packet{header = #diameter_header{is_request = R}} = Pkt,
     recv(R,
@@ -244,11 +252,18 @@ receive_message(TPid, Pkt, Dict0, RecvData)
 
 %% Incoming request ...
 recv(true, false, TPid, Pkt, Dict0, T) ->
-    spawn_request(TPid, Pkt, Dict0, T);
+    try
+        {request, spawn_request(TPid, Pkt, Dict0, T)}
+    catch
+        error: system_limit = E ->  %% discard
+            ?LOG(error, E),
+            discard
+    end;
 
 %% ... answer to known request ...
 recv(false, #request{ref = Ref, handler = Pid} = Req, _, Pkt, Dict0, _) ->
-    Pid ! {answer, Ref, Req, Dict0, Pkt};
+    Pid ! {answer, Ref, Req, Dict0, Pkt},
+    {answer, Pid};
 
 %% Note that failover could have happened prior to this message being
 %% received and triggering failback. That is, both a failover message
@@ -263,7 +278,7 @@ recv(false, #request{ref = Ref, handler = Pid} = Req, _, Pkt, Dict0, _) ->
 recv(false, false, TPid, Pkt, _, _) ->
     ?LOG(discarded, Pkt#diameter_packet.header),
     incr(TPid, {{unknown, 0}, recv, discarded}),
-    ok.
+    discard.
 
 %% spawn_request/4
 
@@ -273,12 +288,7 @@ spawn_request(TPid, Pkt, Dict0, RecvData) ->
     spawn_request(TPid, Pkt, Dict0, ?DEFAULT_SPAWN_OPTS, RecvData).
 
 spawn_request(TPid, Pkt, Dict0, Opts, RecvData) ->
-    try
-        spawn_opt(fun() -> recv_request(TPid, Pkt, Dict0, RecvData) end, Opts)
-    catch
-        error: system_limit = E ->  %% discard
-            ?LOG(error, E)
-    end.
+    spawn_opt(fun() -> recv_request(TPid, Pkt, Dict0, RecvData) end, Opts).
 
 %% ---------------------------------------------------------------------------
 %% recv_request/4