Add diameter_sctp option packet

To determine the wrapping of messages passed to recv callbacks and into
diameter. The default passing of the input stream in transport_data is
probably of no practical use, but has been set since time immemorial.

lib/diameter/src/transport/diameter_sctp.erl

@@ -78,6 +78,7 @@
 
 -type option() :: {sender, boolean()}
                 | sender
+                | {packet, boolean() | raw}
                 | {message_cb, false | diameter:evaluable()}.
 
 -type uint() :: non_neg_integer().
@@ -101,6 +102,8 @@
          streams  :: {uint(), uint()}      %% {InStream, OutStream} counts
                    | undefined,
          os = 0   :: uint(),               %% next output stream
+         packet = true :: boolean()        %% legacy transport_data?
+                        | raw,
          message_cb   :: false | diameter:evaluable(),
          send = false :: pid() | boolean()}).      %% sending process
 
@@ -243,7 +246,8 @@ i(#monitor{transport = TPid} = S) ->
 i({listen, Ref, {Opts, SvcPid, Addrs}}) ->
     monitor(process, SvcPid),
     [_] = diameter_config:subscribe(Ref, transport), %% assert existence
-    {Split, Rest} = proplists:split(Opts, [accept, sender, message_cb]),
+    {Split, Rest}
+        = proplists:split(Opts, [accept, packet, sender, message_cb]),
     OwnOpts = lists:append(Split),
     {LAs, Sock} = AS = open(Addrs, Rest, ?DEFAULT_PORT),
     ok = gen_sctp:listen(Sock, true),
@@ -252,14 +256,15 @@ i({listen, Ref, {Opts, SvcPid, Addrs}}) ->
     #listener{ref = Ref,
               service = SvcPid,
               socket = Sock,
-              opts = [[[M] || {accept, M} <- OwnOpts]
+              opts = [[[M] || {accept, M} <- OwnOpts],
+                      proplists:get_value(packet, OwnOpts, true)
                       | [proplists:get_value(K, OwnOpts, false)
                          || K <- [sender, message_cb]]]};
 
 %% A connecting transport.
 i({connect, Pid, Opts, Addrs, Ref}) ->
     {[Ps | Split], Rest}
-        = proplists:split(Opts, [rport, raddr, sender, message_cb]),
+        = proplists:split(Opts, [rport, raddr, packet, sender, message_cb]),
     OwnOpts = lists:append(Split),
     CB = proplists:get_value(message_cb, OwnOpts, false),
     false == CB orelse (Pid ! {diameter, ack}),
@@ -273,6 +278,7 @@ i({connect, Pid, Opts, Addrs, Ref}) ->
                mode = {connect, connect(Sock, RAs, RP, [])},
                socket = Sock,
                message_cb = CB,
+               packet = proplists:get_value(packet, OwnOpts, true),
                send = proplists:get_value(sender, OwnOpts, false)};
 
 %% An accepting transport spawned by diameter, not yet owning an
@@ -309,12 +315,13 @@ i({K, Ref}, #transport{mode = {accept, _}} = S) ->
             S#transport{parent = Pid};
         {K, T, Opts} when K == peeloff ->  %% association
             {sctp, Sock, _RA, _RP, _Data} = T,
-            [Matches, Sender, CB] = Opts,
+            [Matches, Packet, Sender, CB] = Opts,
             ok = accept_peer(Sock, Matches),
             demonitor(Ref, [flush]),
             false == CB orelse (S#transport.parent ! {diameter, ack}),
             t(T, S#transport{socket = Sock,
                              message_cb = CB,
+                             packet = Packet,
                              send = Sender});
         accept_timeout = T ->
             x(T);
@@ -740,10 +747,9 @@ recv({[#sctp_sndrcvinfo{assoc_id = Id}], _Bin}
     recv(T, S#transport{assoc_id = Id});
 
 %% Inbound Diameter message.
-recv({[#sctp_sndrcvinfo{stream = Id}], Bin}, S)
+recv({[#sctp_sndrcvinfo{}], Bin} = Msg, S)
   when is_binary(Bin) ->
-    Pkt = #diameter_packet{bin = Bin, transport_data = {stream, Id}},
-    message(recv, Pkt, S);
+    message(recv, Msg, S);
 
 recv({_, #sctp_shutdown_event{}}, _) ->
     stop;
@@ -888,7 +894,9 @@ setopts(Sock) ->
 
 %% A message_cb is invoked whenever a message is sent or received, or
 %% to provide acknowledgement of a completed send or discarded
-%% request. See diameter_tcp for semantics.
+%% request. See diameter_tcp for semantics, the only difference being
+%% that a recv callback can get a diameter_packet record as Msg
+%% depending on how/if option packet has been specified.
 
 %% message/3
 
@@ -898,8 +906,8 @@ message(send, false = M, S) ->
 message(ack, _, #transport{message_cb = false} = S) ->
     S;
 
-message(Dir, Msg, #transport{message_cb = CB} = S) ->
-    setopts(S, actions(cb(CB, Dir, Msg), Dir, S)).
+message(Dir, Msg, S) ->
+    setopts(S, actions(cb(S, Dir, Msg), Dir, S)).
 
 %% actions/3
 
@@ -935,8 +943,31 @@ actions(CB, _, S) ->
 
 %% cb/3
 
-cb(false, _, Msg) ->
+cb(#transport{message_cb = false, packet = P}, recv, Msg) ->
+    [pkt(P, true, Msg)];
+
+cb(#transport{message_cb = CB, packet = P}, recv = D, Msg) ->
+    cb(CB, D, pkt(P, false, Msg));
+
+cb(#transport{message_cb = CB}, Dir, Msg) ->
+    cb(CB, Dir, Msg);
+
+cb(false, send, Msg) ->
     [Msg];
 
 cb(CB, Dir, Msg) ->
     diameter_lib:eval([CB, Dir, Msg]).
+
+%% pkt/3
+
+pkt(false, _, {_Info, Bin}) ->
+    Bin;
+
+pkt(true, _, {[#sctp_sndrcvinfo{stream = Id}], Bin}) ->
+    #diameter_packet{bin = Bin, transport_data = {stream, Id}};
+
+pkt(raw, true, {[Info], Bin}) ->
+    #diameter_packet{bin = Bin, transport_data = Info};
+
+pkt(raw, false, {[_], _} = Msg) ->
+    Msg.

lib/diameter/test/diameter_traffic_SUITE.erl

@@ -466,7 +466,9 @@ add_transports(Config) ->
     LRef = ?util:listen(SN,
                         [T,
                          {sender, SS},
-                         {message_cb, ST andalso {?MODULE, message, [4]}}],
+                         {message_cb, ST andalso {?MODULE, message, [4]}}
+                         | [{packet, hd(?util:scramble([false, raw]))}
+                            || T == sctp andalso CS]],
                         [{capabilities_cb, fun capx/2},
                          {pool_size, 8},
                          {spawn_opt, [{min_heap_size, 8096}]},
@@ -1509,6 +1511,8 @@ request(#diameter_base_RAR{}, _Caps) ->
 %% Limit the number of messages received. More can be received if read
 %% in the same packet.
 
+message(recv = D, {[_], Bin}, N) ->
+    message(D, Bin, N);
 message(Dir, #diameter_packet{bin = Bin}, N) ->
     message(Dir, Bin, N);