From bc87eb33f3878051b1d757710b4aa58136169c3a Mon Sep 17 00:00:00 2001
From: Anders Svensson <anders@erlang.org>
Date: Fri, 5 Oct 2012 11:13:11 +0200
Subject: Implement sequence masks

Code should be loaded in this order:

  diameter_session   (sequence/1)
  diameter_peer_fsm  (calls to sequence/1)
  diameter_service   (sequence config, mask in receive_message/3)
  diameter_watchdog  (mask in peer start and receive_message/3)
  diameter_config    (accept sequence config)

Order of diameter and diameter_peer doesn't matter.
---
 lib/diameter/src/base/diameter_watchdog.erl | 58 +++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 12 deletions(-)

(limited to 'lib/diameter/src/base/diameter_watchdog.erl')

diff --git a/lib/diameter/src/base/diameter_watchdog.erl b/lib/diameter/src/base/diameter_watchdog.erl
index 53f5f42396..1045d9ad9f 100644
--- a/lib/diameter/src/base/diameter_watchdog.erl
+++ b/lib/diameter/src/base/diameter_watchdog.erl
@@ -43,6 +43,7 @@
 -include("diameter_internal.hrl").
 
 -define(DEFAULT_TW_INIT, 30000). %% RFC 3539 ch 3.4.1
+-define(NOMASK, {0,32}).  %% default sequence mask
 
 -record(watchdog,
         {%% PCB - Peer Control Block; see RFC 3539, Appendix A
@@ -56,7 +57,8 @@
          parent = self() :: pid(),
          transport       :: pid() | undefined,
          tref :: reference(), %% reference for current watchdog timer
-         message_data}).   %% term passed into diameter_service with message
+         message_data,        %% term passed into diameter_service with message
+         sequence :: diameter:sequence()}).  %% mask
 
 %% start/2
 %%
@@ -118,12 +120,20 @@ make_state({T, Pid, {RecvData,
     random:seed(now()),
     putr(restart, {T, Opts, Svc}),  %% save seeing it in trace
     putr(dwr, dwr(Caps)),           %%
+    {_,_} = Mask = call(Pid, sequence),
     #watchdog{parent = Pid,
-              transport = monitor(diameter_peer_fsm:start(T, Opts, Svc)),
+              transport = monitor(diameter_peer_fsm:start(T,
+                                                          Opts,
+                                                          {Mask, Svc})),
               tw = proplists:get_value(watchdog_timer,
                                        Opts,
                                        ?DEFAULT_TW_INIT),
-              message_data = {RecvData, SvcName, Apps}}.
+              message_data = {RecvData, SvcName, Apps, Mask},
+              sequence = Mask}.
+
+%% Retrieve the sequence mask from the parent from the parent, rather
+%% than having it passed into init/1, for upgrade reasons: the call to
+%% diameter_service:receive_message/3 passes back the mask.
 
 %% handle_call/3
 
@@ -137,7 +147,7 @@ handle_cast(_, State) ->
 
 %% handle_info/2
 
-handle_info(T, State) ->
+handle_info(T, #watchdog{} = State) ->
     case transition(T, State) of
         ok ->
             {noreply, State};
@@ -148,7 +158,11 @@ handle_info(T, State) ->
             ?LOG(stop, T),
             event(State, State#watchdog{status = down}),
             {stop, {shutdown, T}, State}
-    end.
+    end;
+
+handle_info(T, S) ->  %% upgrade
+    handle_info(T, #watchdog{} = list_to_tuple(tuple_to_list(S)
+                                               ++ [?NOMASK])).
 
 event(#watchdog{status = T}, #watchdog{status = T}) ->
     ok;
@@ -312,6 +326,15 @@ transition({state, Pid}, #watchdog{status = S}) ->
 
 %% ===========================================================================
 
+%% Only call "upwards", to the parent service.
+call(Pid, Req) ->
+    try
+        gen_server:call(Pid, Req, infinity)
+    catch
+        exit: Reason ->
+            exit({shutdown, {Req, Reason}})
+    end.
+
 monitor(Pid) ->
     erlang:monitor(process, Pid),
     Pid.
@@ -325,10 +348,16 @@ getr(Key) ->
 eraser(Key) ->
     erase({?MODULE, Key}).
 
-%% encode/1
+%% encode/2
 
-encode(Msg) ->
-    #diameter_packet{bin = Bin} = diameter_codec:encode(?BASE, Msg),
+encode(Msg, Mask) ->
+    Seq = diameter_session:sequence(Mask),
+    Hdr = #diameter_header{version = ?DIAMETER_VERSION,
+                           end_to_end_id = Seq,
+                           hop_by_hop_id = Seq},
+    Pkt = #diameter_packet{header = Hdr,
+                           msg = Msg},
+    #diameter_packet{bin = Bin} = diameter_codec:encode(?BASE, Pkt),
     Bin.
 
 %% okay/2
@@ -400,9 +429,10 @@ close(#watchdog{parent = Pid}) ->
 %% send_watchdog/1
 
 send_watchdog(#watchdog{pending = false,
-                        transport = TPid}
+                        transport = TPid,
+                        sequence = Mask}
               = S) ->
-    TPid ! {send, encode(getr(dwr))},
+    TPid ! {send, encode(getr(dwr), Mask)},
     ?LOG(send, 'DWR'),
     S#watchdog{pending = true}.
 
@@ -606,9 +636,13 @@ restart(S) ->
 %% it's actually in state down rather then initial when receiving
 %% notification of an open connection.
 
-restart({{connect, _} = T, Opts, Svc}, #watchdog{parent = Pid} = S) ->
+restart({{connect, _} = T, Opts, Svc}, #watchdog{parent = Pid,
+                                                 sequence = Mask}
+                                       = S) ->
     Pid ! {reconnect, self()},
-    S#watchdog{transport = monitor(diameter_peer_fsm:start(T, Opts, Svc))};
+    S#watchdog{transport = monitor(diameter_peer_fsm:start(T,
+                                                           Opts,
+                                                           {Mask, Svc}))};
 restart({{accept, _}, _, _}, S) ->
     S.
 %% Don't currently use Opts/Svc in the accept case but having them in
-- 
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