Fix faulty watchdog transition DOWN -> INITIAL

This was the result of the watchdog process exiting as a consequence of
peer death in some casesi, causing a restarted transport to enter
INITIAL when it should enter REOPEN. The watchdog now remains alive as
long as peer shutdown isn't requested and a 'close' message to the
service process (instead of watchdog death) generates 'closed' events
from the service.

1 files changed, 16 insertions, 41 deletions

diff --git a/lib/diameter/src/base/diameter_peer_fsm.erl b/lib/diameter/src/base/diameter_peer_fsm.erl
index b515a599ed..d593d0ab84 100644
--- a/lib/diameter/src/base/diameter_peer_fsm.erl
+++ b/lib/diameter/src/base/diameter_peer_fsm.erl
@@ -126,12 +126,7 @@
 %% State Machine rather than closer to the transport. This is what we
 %% now do below: connect/accept call diameter_watchdog and return the
 %% pid of the watchdog process, and the watchdog in turn calls start/3
-%% below to start the process implementing the Peer State Machine. The
-%% former is a "peer" in diameter_service while the latter is a
-%% "conn". In a sense, diameter_service sees the watchdog as
-%% implementing the Peer State Machine and the process implemented
-%% here as being the transport, not being aware of the watchdog at
-%% all.
+%% below to start the process implementing the Peer State Machine.
 %%
 
 %%% ---------------------------------------------------------------------------
@@ -274,13 +269,12 @@ handle_info(T, #state{} = State) ->
             {noreply, S};
         {stop, Reason} ->
             ?LOG(stop, Reason),
-            x(Reason, State);
+            {stop, {shutdown, Reason}, State};
         stop ->
             ?LOG(stop, T),
-            x(T, State)
+            {stop, {shutdown, T}, State}
     catch
         exit: {diameter_codec, encode, _} = Reason ->
-            close_wd(Reason, State#state.parent),
             ?LOG(stop, Reason),
             %% diameter_codec:encode/2 emits an error report. Only
             %% indicate the probable reason here.
@@ -300,10 +294,6 @@ handle_info(T, #state{} = State) ->
 %% succesfully encoded. It's not checked at diameter:add_transport/2
 %% since this can be called before creating the service.
 
-x(Reason, #state{} = S) ->
-    close_wd(Reason, S),
-    {stop, {shutdown, Reason}, S}.
-
 %% terminate/2
 
 terminate(_, _) ->
@@ -378,9 +368,8 @@ transition({diameter, {recv, Pkt}}, S) ->
     recv(Pkt, S);
 
 %% Timeout when still in the same state ...
-transition({timeout = T, PS}, #state{state = PS} = S) ->
-    close({capx(PS), T}, S),
-    stop;
+transition({timeout = T, PS}, #state{state = PS}) ->
+    {stop, {capx(PS), T}};
 
 %% ... or not.
 transition({timeout, _}, _) ->
@@ -457,7 +446,7 @@ send_CER(#state{state = {'Wait-Conn-Ack', Tmo},
     OH = LCaps#diameter_caps.origin_host,
     req_send_CER(OH, Remote)
         orelse
-        close({already_connected, Remote, LCaps}, S),
+        close({already_connected, Remote, LCaps}),
     CER = build_CER(S),
     ?LOG(send, 'CER'),
     #diameter_packet{header = #diameter_header{end_to_end_id = Eid,
@@ -690,17 +679,17 @@ cea(CEA, RC) ->
     CEA#diameter_base_CEA{'Result-Code' = RC}.
 
 post('CER' = T, RC, Pkt, S) ->
-    [fun close/2, {T, caps(S), {RC, Pkt}}];
+    [fun(_) -> close({T, caps(S), {RC, Pkt}}) end];
 post(_, _, _, _) ->
     ok.
 
 rejected({capabilities_cb, _F, Reason}, T, S) ->
     rejected(Reason, T, S);
 
-rejected(discard, T, S) ->
-    close(T, S);
+rejected(discard, T, _) ->
+    close(T);
 rejected({N, Es}, T, S) ->
-    {answer('CER', N, Es, S), [fun close/2, T]};
+    {answer('CER', N, Es, S), [fun(_) -> close(T) end]};
 rejected(N, T, S) ->
     rejected({N, []}, T, S).
 
@@ -860,7 +849,7 @@ handle_CEA(#diameter_packet{bin = Bin}
     of
         _ -> open(DPkt, SApps, Caps, {connect, hd([_] = IS)}, S)
     catch
-        ?FAILURE(Reason) -> close({'CEA', Reason, Caps, DPkt}, S)
+        ?FAILURE(Reason) -> close({'CEA', Reason, Caps, DPkt})
     end.
 %% Check more than the result code since the peer could send success
 %% regardless. If not 2001 then a peer_up callback could do anything
@@ -880,7 +869,7 @@ recv_CEA(#diameter_packet{header = #diameter_header{version
     T;
 
 recv_CEA(Pkt, S) ->
-    close({'CEA', caps(S), Pkt}, S).
+    close({'CEA', caps(S), Pkt}).
 
 caps(#diameter_service{capabilities = Caps}) ->
     Caps;
@@ -933,14 +922,14 @@ open(Pkt, SupportedApps, Caps, {Type, IS}, #state{parent = Pid,
 
 %% We've advertised TLS support: tell the transport the result
 %% and expect a reply when the handshake is complete.
-tls_ack(true, Caps, Type, IS, #state{transport = TPid} = S) ->
+tls_ack(true, Caps, Type, IS, #state{transport = TPid}) ->
     Ref = make_ref(),
     TPid ! {diameter, {tls, Ref, Type, IS == ?TLS}},
     receive
         {diameter, {tls, Ref}} ->
             ok;
         {'DOWN', _, process, TPid, Reason} ->
-            close({tls_ack, Reason, Caps}, S)
+            close({tls_ack, Reason, Caps})
     end;
 
 %% Or not. Don't send anything to the transport so that transports
@@ -953,25 +942,11 @@ capz(#diameter_caps{} = L, #diameter_caps{} = R) ->
         = list_to_tuple([diameter_caps | lists:zip(tl(tuple_to_list(L)),
                                                    tl(tuple_to_list(R)))]).
 
-%% close/2
+%% close/1
 
-%% Tell the watchdog that our death isn't due to transport failure.
-close(Reason, #state{parent = Pid}) ->
-    close_wd(Reason, Pid),
+close(Reason) ->
     throw({?MODULE, close, Reason}).
 
-%% close_wd/2
-
-%% Ensure the watchdog dies if DPR has been sent ...
-close_wd(_, #state{dpr = false}) ->
-    ok;
-close_wd(Reason, #state{parent = Pid}) ->
-    close_wd(Reason, Pid);
-
-%% ... or otherwise
-close_wd(Reason, Pid) ->
-    Pid ! {close, self(), Reason}.
-
 %% dwa/1
 
 dwa(#diameter_caps{origin_host = OH,