1 files changed, 123 insertions, 22 deletions

diff --git a/lib/diameter/src/base/diameter_codec.erl b/lib/diameter/src/base/diameter_codec.erl
index 06a4f5de64..bf2fe8e7ca 100644
--- a/lib/diameter/src/base/diameter_codec.erl
+++ b/lib/diameter/src/base/diameter_codec.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2010-2014. All Rights Reserved.
+%% Copyright Ericsson AB 2010-2015. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -22,6 +22,8 @@
 -export([encode/2,
          decode/2,
          decode/3,
+         setopts/1,
+         getopt/1,
          collect_avps/1,
          decode_header/1,
          sequence_numbers/1,
@@ -59,6 +61,50 @@
 %%    +-+-+-+-+-+-+-+-+-+-+-+-+-
 
 %%% ---------------------------------------------------------------------------
+%%% # setopts/1
+%%% # getopt/1
+%%% ---------------------------------------------------------------------------
+
+%% These functions are a compromise in the same vein as the use of the
+%% process dictionary in diameter_gen.hrl in generated codec modules.
+%% Instead of rewriting the entire dictionary generation to pass
+%% encode/decode options around, the calling process sets them by
+%% calling setopts/1. At current, the only option is whether or not to
+%% decode binaries as strings, which is used by diameter_types.
+
+setopts(Opts)
+  when is_list(Opts) ->
+    lists:foreach(fun setopt/1, Opts).
+
+%% Decode stringish types to string()? The default true is for
+%% backwards compatibility.
+setopt({string_decode = K, false = B}) ->
+    setopt(K, B);
+
+%% Regard anything but the generated RFC 3588 dictionary as modern.
+%% This affects the interpretation of defaults during the decode
+%% of values of type DiameterURI, this having changed from RFC 3588.
+%% (So much for backwards compatibility.)
+setopt({common_dictionary, diameter_gen_base_rfc3588}) ->
+    setopt(rfc, 3588);
+
+setopt(_) ->
+    ok.
+
+setopt(Key, Value) ->
+    put({diameter, Key}, Value).
+
+getopt(Key) ->
+    case get({diameter, Key}) of
+        undefined when Key == string_decode ->
+            true;
+        undefined when Key == rfc ->
+            6733;
+        V ->
+            V
+    end.
+
+%%% ---------------------------------------------------------------------------
 %%% # encode/2
 %%% ---------------------------------------------------------------------------
 
@@ -90,7 +136,7 @@ encode(Mod, Msg) ->
                                   msg = Msg}).
 
 e(_, #diameter_packet{msg = [#diameter_header{} = Hdr | As]} = Pkt) ->
-    try encode_avps(As) of
+    try encode_avps(reorder(As)) of
         Avps ->
             Length = size(Avps) + 20,
 
@@ -183,26 +229,50 @@ values(Avps) ->
 
 %% Message as a list of #diameter_avp{} ...
 encode_avps(_, _, [#diameter_avp{} | _] = Avps) ->
-    encode_avps(reorder(Avps, [], Avps));
+    encode_avps(reorder(Avps));
 
 %% ... or as a tuple list or record.
 encode_avps(Mod, MsgName, Values) ->
     Mod:encode_avps(MsgName, Values).
 
 %% reorder/1
+%%
+%% Reorder AVPs for the relay case using the index field of
+%% diameter_avp records. Decode populates this field in collect_avps
+%% and presents AVPs in reverse order. A relay then sends the reversed
+%% list with a Route-Record AVP prepended. The goal here is just to do
+%% lists:reverse/1 in Grouped AVPs and the outer list, but only in the
+%% case there are indexed AVPs at all, so as not to reverse lists that
+%% have been explicilty sent (unindexed, in the desired order) as a
+%% diameter_avp list. The effect is the same as lists:keysort/2, but
+%% only on the cases we expect, not a general sort.
+
+reorder(Avps) ->
+    case reorder(Avps, []) of
+        false ->
+            Avps;
+        Sorted ->
+            Sorted
+    end.
+
+%% reorder/3
 
-reorder([#diameter_avp{index = 0} | _] = Avps, Acc, _) ->
+%% In case someone has reversed the list already. (Not likely.)
+reorder([#diameter_avp{index = 0} | _] = Avps, Acc) ->
     Avps ++ Acc;
 
-reorder([#diameter_avp{index = N} = A | Avps], Acc, _)
+%% Assume indexed AVPs are in reverse order.
+reorder([#diameter_avp{index = N} = A | Avps], Acc)
   when is_integer(N) ->
     lists:reverse(Avps, [A | Acc]);
 
-reorder([H | T], Acc, Avps) ->
-    reorder(T, [H | Acc], Avps);
+%% An unindexed AVP.
+reorder([H | T], Acc) ->
+    reorder(T, [H | Acc]);
 
-reorder([], Acc, _) ->
-    Acc.
+%% No indexed members.
+reorder([], _) ->
+    false.
 
 %% encode_avps/1
 
@@ -237,15 +307,35 @@ rec2msg(Mod, Rec) ->
 
 %% Unsuccessfully decoded AVPs will be placed in #diameter_packet.errors.
 
--spec decode(module(), #diameter_packet{} | binary())
+-spec decode(module() | {module(), module()}, #diameter_packet{} | binary())
    -> #diameter_packet{}.
 
+%% An Answer setting the E-bit. The application dictionary is needed
+%% for the best-effort decode of Failed-AVP, and the best way to make
+%% this available to the AVP decode in diameter_gen.hrl, without
+%% having to rewrite the entire codec generation, is to place it in
+%% the process dictionary. It's the code in diameter_gen.hrl (that's
+%% included by every generated codec module) that looks for the entry.
+%% Not ideal, but it solves the problem relatively simply.
+decode({Mod, Mod}, Pkt) ->
+    decode(Mod, Pkt);
+decode({Mod, AppMod}, Pkt) ->
+    Key = {?MODULE, dictionary},
+    put(Key, AppMod),
+    try
+        decode(Mod, Pkt)
+    after
+        erase(Key)
+    end;
+
+%% Or not: a request, or an answer not setting the E-bit.
 decode(Mod, Pkt) ->
     decode(Mod:id(), Mod, Pkt).
 
-%% If we're a relay application then just extract the avp's without
-%% any decoding of their data since we don't know the application in
-%% question.
+%% decode/3
+
+%% Relay application: just extract the avp's without any decoding of
+%% their data since we don't know the application in question.
 decode(?APP_ID_RELAY, _, #diameter_packet{} = Pkt) ->
     case collect_avps(Pkt) of
         {E, As} ->
@@ -274,6 +364,8 @@ decode(Id, Mod, Bin)
   when is_binary(Bin) ->
     decode(Id, Mod, #diameter_packet{header = decode_header(Bin), bin = Bin}).
 
+%% decode_avps/4
+
 decode_avps(MsgName, Mod, Pkt, {E, Avps}) ->
     ?LOG(invalid_avp_length, Pkt#diameter_packet.header),
     #diameter_packet{errors = Failed}
@@ -368,6 +460,9 @@ sequence_numbers(#diameter_packet{bin = Bin})
 sequence_numbers(#diameter_packet{header = #diameter_header{} = H}) ->
     sequence_numbers(H);
 
+sequence_numbers(#diameter_packet{msg = [#diameter_header{} = H | _]}) ->
+    sequence_numbers(H);
+
 sequence_numbers(#diameter_header{hop_by_hop_id = H,
                                   end_to_end_id = E}) ->
     {H,E};
@@ -539,14 +634,18 @@ split_data(Bin, Len) ->
         <<Data:Len/binary, _:Pad/binary, Rest/binary>> ->
             {Data, Rest};
         _ ->
-            %% Header length points past the end of the message. As
-            %% stated in the 6733 text above, it's sufficient to
-            %% return a zero-filled minimal payload if this is a
-            %% request. Do this (in cases that we know the type) by
-            %% inducing a decode failure and letting the dictionary's
-            %% decode (in diameter_gen) deal with it. Here we don't
-            %% know type. If the type isn't known, then the decode
-            %% just strips the extra bit.
+            %% Header length points past the end of the message, or
+            %% doesn't span the header. As stated in the 6733 text
+            %% above, it's sufficient to return a zero-filled minimal
+            %% payload if this is a request. Do this (in cases that we
+            %% know the type) by inducing a decode failure and letting
+            %% the dictionary's decode (in diameter_gen) deal with it.
+            %%
+            %% Note that the extra bit can only occur in the trailing
+            %% AVP of a message or Grouped AVP, since a faulty AVP
+            %% Length is otherwise indistinguishable from a correct
+            %% one here, since we don't know the types of the AVPs
+            %% being extracted.
             {<<0:1, Bin/binary>>, <<>>}
     end.
 
@@ -560,6 +659,8 @@ split_data(Bin, Len) ->
 %% dictionary doesn't know about specific AVP's.
 
 %% Grouped AVP whose components need packing ...
+pack_avp([#diameter_avp{} = A | Avps]) ->
+    pack_avp(A#diameter_avp{data = Avps});
 pack_avp(#diameter_avp{data = [#diameter_avp{} | _] = Avps} = A) ->
     pack_avp(A#diameter_avp{data = encode_avps(Avps)});
 
@@ -593,8 +694,8 @@ pack_avp(#diameter_avp{code = undefined, data = B})
     Len = size(<<H:5/binary, _:24, T/binary>> = <<B/binary, 0:Pad>>),
     <<H/binary, Len:24, T/binary>>;
 
-%% ... from a dictionary compiled against old code in diameter_gen ...
 %% ... when ignoring errors in Failed-AVP ...
+%% ... during a relay encode ...
 pack_avp(#diameter_avp{data = <<0:1, B/binary>>} = A) ->
     pack_avp(A#diameter_avp{data = B});