Merge branch 'maint'

11 files changed, 265 insertions, 183 deletions

diff --git a/lib/diameter/doc/src/diameter.xml b/lib/diameter/doc/src/diameter.xml
index b7be184058..0169afb619 100644
--- a/lib/diameter/doc/src/diameter.xml
+++ b/lib/diameter/doc/src/diameter.xml
@@ -799,7 +799,7 @@ be matched by corresponding &capability; configuration, of
 
 <tag>
 <marker id="decode_format"/>
-<c>{decode_format, record | list | map | false}</c></tag>
+<c>{decode_format, record | list | map | none}</c></tag>
 <item>
 <p>
 The format of decoded messages and grouped AVPs in the <c>msg</c> field
@@ -808,10 +808,10 @@ records respectively.
 If <c>record</c> then a record whose definition is generated from the
 dictionary file in question.
 If <c>list</c> or <c>map</c> then a <c>[Name | Avps]</c> pair where
-<c>Avps</c> is either a list of AVP name/values pairs or a map keyed on
+<c>Avps</c> is a list of AVP name/values pairs or a map keyed on
 AVP names respectively.
-If <c>false</c> then the representation is omitted and <c>msg</c> and
-<c>value</c> fields are set to <c>false</c>.
+If <c>none</c> then the atom-value message name, or <c>undefined</c>
+for a Grouped AVP.
 See also &codec_message;.</p>
 
 <p>
diff --git a/lib/diameter/doc/src/diameter_codec.xml b/lib/diameter/doc/src/diameter_codec.xml
index 0846334d23..5124b49484 100644
--- a/lib/diameter/doc/src/diameter_codec.xml
+++ b/lib/diameter/doc/src/diameter_codec.xml
@@ -4,7 +4,10 @@
   '<seealso marker="diameter_dict#MESSAGE_RECORDS">diameter_dict(4)</seealso>'>
   <!ENTITY types
   '<seealso marker="diameter_dict#DATA_TYPES">diameter_dict(4)</seealso>'>
-  <!ENTITY % also SYSTEM "seealso.ent" >
+  <!ENTITY decode_format
+  '<seealso marker="diameter#decode_format">decode format</seealso>'>
+
+<!ENTITY % also SYSTEM "seealso.ent" >
   <!ENTITY % here SYSTEM "seehere.ent" >
   %also;
   %here;
@@ -145,7 +148,8 @@ question.</p>
 <p>
 The decoded value of an AVP.
 Will be <c>undefined</c> on decode if the data bytes could
-not be decoded or the AVP is unknown.
+not be decoded, the AVP is unknown, or if the &decode_format; is
+<c>none</c>.
 The type of a decoded value is as document in &types;.</p>
 </item>
 
@@ -243,8 +247,7 @@ Equivalently, a message can also be encoded as a list whose head is
 the atom-valued message name (as specified in the relevant dictionary
 file) and whose tail is either a list of AVP name/values
 pairs or a map with values keyed on AVP names.
-The format at decode is determined by &mod_service_opt;
-<c>decode_format</c>.
+The format at decode is determined by &mod_decode_format;.
 Any of the formats is accepted at encode.</p>
 
 <p>
@@ -288,15 +291,16 @@ value other than <c>undefined</c>.</p>
 <item>
 <p>
 The incoming/outgoing message.
-For an incoming message, a record if the message can be
-decoded in a non-relay application, <c>undefined</c> otherwise.
+For an incoming message, a term corresponding to the configured
+&decode_format; if the message can be decoded in a non-relay
+application, <c>undefined</c> otherwise.
 For an outgoing message, setting a <c>[&header; | &avp;]</c> list is
 equivalent to setting the <c>header</c> and <c>avps</c> fields to the
 corresponding values.</p>
 
 <warning>
 <p>
-A record-valued <c>msg</c> field does <em>not</em> imply an absence of
+A value in the <c>msg</c> field does <em>not</em> imply an absence of
 decode errors.
 The <c>errors</c> field should also be examined.</p>
 </warning>
diff --git a/lib/diameter/doc/src/seealso.ent b/lib/diameter/doc/src/seealso.ent
index ef6af1a3d0..c5a53670d0 100644
--- a/lib/diameter/doc/src/seealso.ent
+++ b/lib/diameter/doc/src/seealso.ent
@@ -72,6 +72,7 @@ significant.
 <!ENTITY watchdog_timer '<seealso marker="#watchdog_timer">watchdog_timer</seealso>'>
 
 <!ENTITY mod_string_decode '<seealso marker="diameter#service_opt">diameter:service_opt()</seealso> <seealso marker="diameter#string_decode">string_decode</seealso>'>
+<!ENTITY mod_decode_format '<seealso marker="diameter#service_opt">diameter:service_opt()</seealso> <seealso marker="diameter#decode_format">decode_format</seealso>'>
 
 <!-- diameter_app -->
 
diff --git a/lib/diameter/src/base/diameter.erl b/lib/diameter/src/base/diameter.erl
index 3b41feac0d..69ef6f4ec0 100644
--- a/lib/diameter/src/base/diameter.erl
+++ b/lib/diameter/src/base/diameter.erl
@@ -340,7 +340,7 @@ call(SvcName, App, Message) ->
    :: record
     | list
     | map
-    | false
+    | none
     | record_from_map.
 
 -type strict_arities()
diff --git a/lib/diameter/src/base/diameter_config.erl b/lib/diameter/src/base/diameter_config.erl
index 4721be1ca0..284f885884 100644
--- a/lib/diameter/src/base/diameter_config.erl
+++ b/lib/diameter/src/base/diameter_config.erl
@@ -588,8 +588,7 @@ opt(service, {K, false})
        K == use_shared_peers;
        K == monitor;
        K == restrict_connections;
-       K == strict_arities;
-       K == decode_format ->
+       K == strict_arities ->
     true;
 
 opt(service, {K, true})
@@ -602,6 +601,7 @@ opt(service, {decode_format, T})
   when T == record;
        T == list;
        T == map;
+       T == none;
        T == record_from_map ->
     true;
 
@@ -665,9 +665,8 @@ opt(transport, {applications, As}) ->
     is_list(As);
 
 opt(transport, {capabilities, Os}) ->
-    is_list(Os) andalso case encode_CER(Os) of
-                            ok -> true;
-                            No -> {error, No}
+    is_list(Os) andalso try ok = encode_CER(Os), true
+                        catch ?FAILURE(No) -> {error, No}
                         end;
 
 opt(_, {K, Tmo})
diff --git a/lib/diameter/src/base/diameter_gen.erl b/lib/diameter/src/base/diameter_gen.erl
index 7a1a46ec52..0aea982a54 100644
--- a/lib/diameter/src/base/diameter_gen.erl
+++ b/lib/diameter/src/base/diameter_gen.erl
@@ -45,7 +45,7 @@
 -define(THROW(T), throw({?MODULE, T})).
 
 -type parent_name()   :: atom().  %% parent = Message or AVP
--type parent_record() :: tuple(). %%
+-type parent_record() :: tuple() | avp_values() | map().
 -type avp_name()   :: atom().
 -type avp_record() :: tuple().
 -type avp_values() :: [{avp_name(), term()}].
@@ -61,9 +61,7 @@
 %% # encode_avps/3
 %% ---------------------------------------------------------------------------
 
--spec encode_avps(parent_name(),
-                  parent_record() | avp_values() | map(),
-                  map())
+-spec encode_avps(parent_name(), parent_record(), map())
    -> iolist()
     | no_return().
 
@@ -232,13 +230,13 @@ enc(AvpName, Value, Opts, Mod) ->
 %% ---------------------------------------------------------------------------
 
 -spec decode_avps(parent_name(), binary(), map())
-   -> {parent_record(), [avp()], Failed}
+   -> {parent_record() | parent_name(), [avp()], Failed}
  when Failed :: [{5000..5999, #diameter_avp{}}].
 
 decode_avps(Name, Bin, #{module := Mod, decode_format := Fmt} = Opts) ->
     Strict = mget(strict_arities, Opts, decode),
     [AM, Avps, Failed | Rec]
-        = decode(Bin, Name, Mod, Fmt, Strict, Opts, #{}),
+        = decode(Bin, Name, Mod, Fmt, Strict, Opts, 0, #{}),
     %% AM counts the number of top-level AVPs, which missing/5 then
     %% uses when appending 5005 errors.
     {reformat(Name, Rec, Strict, Mod, Fmt),
@@ -249,7 +247,7 @@ decode_avps(Name, Bin, #{module := Mod, decode_format := Fmt} = Opts) ->
 %% encountered. Failed-AVP should typically contain the first
 %% error encountered.
 
-%% decode/7
+%% decode/8
 
 decode(<<Code:32, V:1, M:1, P:1, _:5, Len:24, I:V/unit:32, Rest/binary>>,
        Name,
@@ -257,6 +255,7 @@ decode(<<Code:32, V:1, M:1, P:1, _:5, Len:24, I:V/unit:32, Rest/binary>>,
        Fmt,
        Strict,
        Opts,
+       Idx,
        AM) ->
     decode(Rest,
            Code,
@@ -270,21 +269,23 @@ decode(<<Code:32, V:1, M:1, P:1, _:5, Len:24, I:V/unit:32, Rest/binary>>,
            Fmt,
            Strict,
            Opts,
+           Idx,
            AM);
 
-decode(<<>>, Name, Mod, Fmt, Strict, _, AM) ->
+decode(<<>>, Name, Mod, Fmt, Strict, _, _, AM) ->
     [AM, [], [] | newrec(Fmt, Mod, Name, Strict)];
 
-decode(Bin, Name, Mod, Fmt, Strict, _, AM) ->
-    Avp = #diameter_avp{data = Bin},
+decode(Bin, Name, Mod, Fmt, Strict, _, Idx, AM) ->
+    Avp = #diameter_avp{data = Bin, index = Idx},
     [AM, [Avp], [{5014, Avp}] | newrec(Fmt, Mod, Name, Strict)].
 
-%% decode/13
+%% decode/14
 
-decode(Bin, Code, Vid, DataLen, Pad, M, P, Name, Mod, Fmt, Strict, Opts0, AM0) ->
+decode(Bin, Code, Vid, DataLen, Pad, M, P, Name, Mod, Fmt, Strict, Opts0,
+       Idx, AM0) ->
     case Bin of
         <<Data:DataLen/binary, _:Pad/binary, T/binary>> ->
-            {NameT, AvpName, Arity, {Idx, AM}}
+            {NameT, Field, Arity, {I, AM}}
                 = incr(Name, Code, Vid, M, Mod, Strict, Opts0, AM0),
 
             Opts = setopts(NameT, Name, M, Opts0),
@@ -300,11 +301,11 @@ decode(Bin, Code, Vid, DataLen, Pad, M, P, Name, Mod, Fmt, Strict, Opts0, AM0) -
                                 type = type(NameT),
                                 index = Idx},
 
-            Dec = decode(Data, Name, NameT, Mod, Opts, Avp),    %% decode
-            Acc = decode(T, Name, Mod, Fmt, Strict, Opts, AM),  %% recurse
-            acc(Acc, Dec, Name, AvpName, Arity, Strict, Mod, Opts);
+            Dec = decode1(Data, Name, NameT, Mod, Fmt, Opts, Avp),
+            Acc = decode(T, Name, Mod, Fmt, Strict, Opts, Idx+1, AM),%% recurse
+            acc(Acc, Dec, I, Name, Field, Arity, Strict, Mod, Opts);
         _ ->
-            {NameT, _AvpName, _Arity, {Idx, AM}}
+            {NameT, _Field, _Arity, {_, AM}}
                 = incr(Name, Code, Vid, M, Mod, Strict, Opts0, AM0),
 
             Avp = #diameter_avp{code = Code,
@@ -323,9 +324,14 @@ decode(Bin, Code, Vid, DataLen, Pad, M, P, Name, Mod, Fmt, Strict, Opts0, AM0) -
 
 incr(Name, Code, Vid, M, Mod, Strict, Opts, AM0) ->
     NameT = Mod:avp_name(Code, Vid), %% {AvpName, Type} | 'AVP'
-    AvpName = field(NameT),
-    Arity = avp_arity(Name, AvpName, Mod, Opts, M),
-    {NameT, AvpName, Arity, incr(AvpName, Arity, Strict, AM0)}.
+    Field = field(NameT),            %% AvpName | 'AVP'
+    Arity = avp_arity(Name, Field, Mod, Opts, M),
+    if 0 == Arity, 'AVP' /= Field ->
+            A = pack_arity(Name, Field, Opts, Mod, M),
+            {NameT, 'AVP', A, incr('AVP', A, Strict, AM0)};
+       true ->
+            {NameT, Field, Arity, incr(Field, Arity, Strict, AM0)}
+    end.
 
 %% Data is a truncated header if command_code = undefined, otherwise
 %% payload bytes. The former is padded to the length of a header if
@@ -342,9 +348,8 @@ setopts({_, Type}, Name, M, Opts) ->
 
 %% incr/4
 
-incr(F, A, SA, AM)
-  when F == 'AVP';
-       A == ?ANY;
+incr(_, A, SA, AM)
+  when A == ?ANY;
        A == 0;
        SA /= decode ->
     {undefined, AM};
@@ -444,10 +449,10 @@ field({AvpName, _}) ->
 field(_) ->
     'AVP'.
 
-%% decode/6
+%% decode1/7
 
 %% AVP not in dictionary.
-decode(_Data, _Name, 'AVP', _Mod, _Opts, Avp) ->
+decode1(_Data, _Name, 'AVP', _Mod, _Fmt, _Opts, Avp) ->
     Avp;
 
 %% 6733, 4.4:
@@ -497,7 +502,7 @@ decode(_Data, _Name, 'AVP', _Mod, _Opts, Avp) ->
 %% defined the RFC's "unrecognized", which is slightly stronger than
 %% "not defined".)
 
-decode(Data, Name, {AvpName, Type}, Mod, Opts, Avp) ->
+decode1(Data, Name, {AvpName, Type}, Mod, Fmt, Opts, Avp) ->
     #{dictionary := AppMod, failed_avp := Failed}
         = Opts,
 
@@ -511,26 +516,39 @@ decode(Data, Name, {AvpName, Type}, Mod, Opts, Avp) ->
     %% list of component AVPs.
 
     try avp_decode(Data, AvpName, Opts, DecMod, Mod) of
-        {Rec, As} when Type == 'Grouped' ->
-            A = Avp#diameter_avp{value = Rec},
-            [A | As];
-        V when Type /= 'Grouped' ->
-            Avp#diameter_avp{value = V}
+        V ->
+            set(Type, Fmt, Avp, V)
     catch
         throw: {?MODULE, T} ->
-            decode_error(Failed, T, Avp);
+            decode_error(Failed, Fmt, T, Avp);
         error: Reason ->
             decode_error(Failed, Reason, Name, Mod, Opts, Avp)
     end.
 
-%% decode_error/3
+%% set/4
+
+set('Grouped', none, Avp, V) ->
+    {_Rec, As} = V,
+    [Avp | As];
+
+set('Grouped', _, Avp, V) ->
+    {Rec, As} = V,
+    [Avp#diameter_avp{value = Rec} | As];
+
+set(_, _, Avp, V) ->
+    Avp#diameter_avp{value = V}.
+
+%% decode_error/4
 %%
 %% Error when decoding a grouped AVP.
 
-decode_error(true, {Rec, _, _}, Avp) ->
+decode_error(true, none, _, Avp) ->
+    Avp;
+
+decode_error(true, _, {Rec, _, _}, Avp) ->
     Avp#diameter_avp{value = Rec};
 
-decode_error(false, {_, ComponentAvps, [{RC,A} | _]}, Avp) ->
+decode_error(false, _, {_, ComponentAvps, [{RC,A} | _]}, Avp) ->
     {RC, [Avp | ComponentAvps], Avp#diameter_avp{data = [A]}}.
 
 %% decode_error/6
@@ -577,61 +595,55 @@ set_failed('Failed-AVP', #{failed_avp := false} = Opts) ->
 set_failed(_, Opts) ->
     Opts.
 
-%% acc/8
+%% acc/9
 
-acc([AM | Acc], As, Name, AvpName, Arity, Strict, Mod, Opts) ->
-    [AM | acc1(Acc, As, Name, AvpName, Arity, Strict, Mod, Opts)].
+acc([AM | Acc], As, I, Name, Field, Arity, Strict, Mod, Opts) ->
+    [AM | acc1(Acc, As, I, Name, Field, Arity, Strict, Mod, Opts)].
 
-%% acc1/8
+%% acc1/9
 
 %% Faulty AVP, not grouped.
-acc1(Acc, {_RC, Avp} = E, _, _, _, _, _, _) ->
+acc1(Acc, {_RC, Avp} = E, _, _, _, _, _, _, _) ->
     [Avps, Failed | Rec] = Acc,
     [[Avp | Avps], [E | Failed] | Rec];
 
 %% Faulty component in grouped AVP.
-acc1(Acc, {RC, As, Avp}, _, _, _, _, _, _) ->
+acc1(Acc, {RC, As, Avp}, _, _, _, _, _, _, _) ->
     [Avps, Failed | Rec] = Acc,
     [[As | Avps], [{RC, Avp} | Failed] | Rec];
 
 %% Grouped AVP ...
-acc1([Avps | Acc], [Avp|_] = As, Name, AvpName, Arity, Strict, Mod, Opts) ->
-    [[As|Avps] | acc2(Acc, Avp, Name, AvpName, Arity, Strict, Mod, Opts)];
+acc1([Avps | Acc], [Avp|_] = As, I, Name, Field, Arity, Strict, Mod, Opts) ->
+    [[As|Avps] | acc2(Acc, Avp, I, Name, Field, Arity, Strict, Mod, Opts)];
 
 %% ... or not.
-acc1([Avps | Acc], Avp, Name, AvpName, Arity, Strict, Mod, Opts) ->
-    [[Avp|Avps] | acc2(Acc, Avp, Name, AvpName, Arity, Strict, Mod, Opts)].
+acc1([Avps | Acc], Avp, I, Name, Field, Arity, Strict, Mod, Opts) ->
+    [[Avp|Avps] | acc2(Acc, Avp, I, Name, Field, Arity, Strict, Mod, Opts)].
 
-%% acc2/8
+%% acc2/9
 
 %% No errors, but nowhere to pack.
-acc2(Acc, Avp, _, 'AVP', 0, _, _, _) ->
+acc2(Acc, Avp, _, _, 'AVP', 0, _, _, _) ->
     [Failed | Rec] = Acc,
     [[{rc(Avp), Avp} | Failed] | Rec];
 
-%% No AVP of this name: try to pack as 'AVP'.
-acc2(Acc, Avp, Name, AvpName, 0, Strict, Mod, Opts) ->
-    M = Avp#diameter_avp.is_mandatory,
-    Arity = pack_arity(Name, AvpName, Opts, Mod, M),
-    acc2(Acc, Avp, Name, 'AVP', Arity, Strict, Mod, Opts);
-
 %% Relaxed arities.
-acc2(Acc, Avp, _, AvpName, Arity, Strict, Mod, _)
+acc2(Acc, Avp, _, _, Field, Arity, Strict, Mod, _)
   when Strict /= decode ->
-    pack(Arity, AvpName, Avp, Mod, Acc);
+    pack(Arity, Field, Avp, Mod, Acc);
 
 %% No maximum arity.
-acc2(Acc, Avp, _, AvpName, {_,'*'} = Arity, _, Mod, _) ->
-    pack(Arity, AvpName, Avp, Mod, Acc);
+acc2(Acc, Avp, _, _, Field, {_,'*'} = Arity, _, Mod, _) ->
+    pack(Arity, Field, Avp, Mod, Acc);
 
 %% Or check.
-acc2(Acc, Avp, _, AvpName, Arity, _, Mod, _) ->
+acc2(Acc, Avp, I, _, Field, Arity, _, Mod, _) ->
     Mx = max_arity(Arity),
-    if Mx =< Avp#diameter_avp.index ->
+    if Mx =< I ->
             [Failed | Rec] = Acc,
             [[{5009, Avp} | Failed] | Rec];
        true ->
-            pack(Arity, AvpName, Avp, Mod, Acc)
+            pack(Arity, Field, Avp, Mod, Acc)
     end.
 
 %% 3588/6733:
@@ -723,8 +735,9 @@ pack(Arity, F, Avp, Mod, [Failed | Rec]) ->
 
 %% set/5
 
-set(_, _, _, _, false = No) ->
-    No;
+set(_, _, _, _, None)
+  when is_atom(None) ->
+    None;
 
 set(1, F, Value, _, Map)
   when is_map(Map) ->
@@ -818,8 +831,8 @@ empty(Name, #{module := Mod} = Opts) ->
 
 %% newrec/4
 
-newrec(false = No, _, _, _) ->
-    No;
+newrec(none, _, Name, _) ->
+    Name;
 
 newrec(record, Mod, Name, T)
   when T /= decode ->
diff --git a/lib/diameter/src/base/diameter_service.erl b/lib/diameter/src/base/diameter_service.erl
index 802e6e7243..3bd023a6f2 100644
--- a/lib/diameter/src/base/diameter_service.erl
+++ b/lib/diameter/src/base/diameter_service.erl
@@ -725,9 +725,13 @@ init_peers() ->
                                %%  TPid}
 
 service_opts(Opts) ->
-    T = {strict_arities, true},
-    maps:merge(maps:from_list([{monitor, false} | def_opts() -- [T]]),
-               maps:from_list(Opts -- [T])).
+    remove([{strict_arities, true}],
+           maps:merge(maps:from_list([{monitor, false} | def_opts()]),
+                      maps:from_list(Opts))).
+
+remove(List, Map) ->
+    maps:filter(fun(K,V) -> not lists:member({K,V}, List) end,
+                Map).
 
 def_opts() ->  %% defaults on the service map
     [{share_peers, false},
diff --git a/lib/diameter/src/base/diameter_traffic.erl b/lib/diameter/src/base/diameter_traffic.erl
index b89c4648d1..1a4bb4d0bf 100644
--- a/lib/diameter/src/base/diameter_traffic.erl
+++ b/lib/diameter/src/base/diameter_traffic.erl
@@ -1032,15 +1032,15 @@ answer_message(RC,
                               origin_realm = {OR,_}},
                #diameter_packet{avps = Avps,
                                 errors = Es}) ->
-    {Code, _, Vid} = Dict0:avp_header('Session-Id'),
     ['answer-message', {'Origin-Host', OH},
                        {'Origin-Realm', OR},
-                       {'Result-Code', RC}]
-        ++ session_id(Code, Vid, Avps)
-        ++ failed_avp(RC, Es).
+                       {'Result-Code', RC}
+     | session_id(Dict0, Avps)
+       ++ failed_avp(RC, Es)
+       ++ proxy_info(Dict0, Avps)].
 
-session_id(Code, Vid, Avps)
-  when is_list(Avps) ->
+session_id(Dict0, Avps) ->
+    {Code, _, Vid} = Dict0:avp_header('Session-Id'),
     try
         #diameter_avp{data = Bin} = find_avp(Code, Vid, Avps),
         [{'Session-Id', [Bin]}]
@@ -1058,6 +1058,14 @@ failed_avp(RC, [_ | Es]) ->
 failed_avp(_, [] = No) ->
     No.
 
+proxy_info(Dict0, Avps) ->
+    {Code, _, Vid} = Dict0:avp_header('Proxy-Info'),
+    [{'AVP', [A#diameter_avp{value = undefined}
+              || [#diameter_avp{code = C, vendor_id = I} = A | _]
+                     <- Avps,
+                 C == Code,
+                 I == Vid]}].
+
 %% find_avp/3
 
 %% Grouped ...
@@ -1892,16 +1900,12 @@ str(T) ->
 
 %% get_avp/3
 %%
-%% Find an AVP in a message of one of three forms:
-%%
-%% - a message record (as generated from a .dia spec) or
-%% - a list of an atom message name followed by 2-tuple, avp name/value pairs.
-%% - a list of a #diameter_header{} followed by #diameter_avp{} records,
-%%
-%% In the first two forms a dictionary module is used at encode to
-%% identify the type of the AVP and its arity in the message in
-%% question. The third form allows messages to be sent as is, without
-%% a dictionary, which is needed in the case of relay agents, for one.
+%% Find an AVP in a message in one of the decoded formats, or as a
+%% header/avps list. There are only four AVPs that are extracted here:
+%% Result-Code and Experimental-Result in order when constructing
+%% counter keys, and Destination-Host/Realm when selecting a next-hop
+%% peer. Experimental-Result is the only of type Grouped, and is given
+%% special treatment in order to return the value as a record.
 
 %% Messages will be header/avps list as a relay and the only AVP's we
 %% look for are in the common dictionary. This is required since the
@@ -1910,12 +1914,12 @@ str(T) ->
 get_avp(?RELAY, Name, Msg) ->
     get_avp(?BASE, Name, Msg);
 
-%% Message is a header/avps list.
+%% Message as header/avps list.
 get_avp(Dict, Name, [#diameter_header{} | Avps]) ->
     try
-        {Code, _, VId} = Dict:avp_header(Name),
-        A = find_avp(Code, VId, Avps),
-        (avp_decode(Dict, Name, ungroup(A)))#diameter_avp{name = Name}
+        {Code, _, Vid} = Dict:avp_header(Name),
+        A = find_avp(Code, Vid, Avps),
+        avp_decode(Dict, Name, ungroup(A))
     catch
         error: _ ->
             undefined
@@ -1925,20 +1929,33 @@ get_avp(Dict, Name, [#diameter_header{} | Avps]) ->
 get_avp(_, Name, [_MsgName | Avps]) ->
     case find(Name, Avps) of
         {_, V} ->
-            #diameter_avp{name = Name, value = V};
+            #diameter_avp{name = Name, value = value(Name, V)};
         _ ->
             undefined
     end;
 
-%% ... or record (but not necessarily).
+%% ... or record.
 get_avp(Dict, Name, Rec) ->
-    try
-        #diameter_avp{name = Name, value = Dict:'#get-'(Name, Rec)}
+    try Dict:'#get-'(Name, Rec) of
+        V ->
+            #diameter_avp{name = Name, value = value(Name, V)}
     catch
         error:_ ->
             undefined
     end.
 
+value('Experimental-Result' = N, #{'Vendor-Id' := Vid,
+                                   'Experimental-Result-Code' := RC}) ->
+    {N, Vid, RC};
+value('Experimental-Result' = N, [{'Experimental-Result-Code', RC},
+                                  {'Vendor-Id', Vid}]) ->
+    {N, Vid, RC};
+value('Experimental-Result' = N, [{'Vendor-Id', Vid},
+                                  {'Experimental-Result-Code', RC}]) ->
+    {N, Vid, RC};
+value(_, V) ->
+    V.
+
 %% find/2
 
 find(Key, Map)
@@ -1968,14 +1985,25 @@ ungroup(Avp) ->
 
 %% avp_decode/3
 
+%% Ensure Experimental-Result is decoded as record, since this format
+%% is used for counter keys.
+avp_decode(Dict, 'Experimental-Result' = N, #diameter_avp{data = Bin}
+                                            = Avp)
+  when is_binary(Bin) ->
+    {V,_} = Dict:avp(decode, Bin, N, decode_opts(Dict)),
+    Avp#diameter_avp{name = N, value = V};
+
 avp_decode(Dict, Name, #diameter_avp{value = undefined,
                                      data = Bin}
                        = Avp)
   when is_binary(Bin) ->
     V = Dict:avp(decode, Bin, Name, decode_opts(Dict)),
-    Avp#diameter_avp{value = V};
-avp_decode(_, _, #diameter_avp{} = Avp) ->
-    Avp.
+    Avp#diameter_avp{name = Name, value = V};
+
+avp_decode(_, Name, #diameter_avp{} = Avp) ->
+    Avp#diameter_avp{name = Name}.
+
+%% cb/3
 
 cb(#diameter_app{module = [_|_] = M}, F, A) ->
     eval(M, F, A).
@@ -1992,4 +2020,5 @@ decode_opts(Dict) ->
       string_decode => false,
       strict_mbit => false,
       failed_avp => false,
+      module => Dict,
       dictionary => Dict}.
diff --git a/lib/diameter/src/base/diameter_watchdog.erl b/lib/diameter/src/base/diameter_watchdog.erl
index bb671e9860..c08e2da672 100644
--- a/lib/diameter/src/base/diameter_watchdog.erl
+++ b/lib/diameter/src/base/diameter_watchdog.erl
@@ -72,7 +72,7 @@
                      restrict := boolean(),
                      suspect := non_neg_integer(), %% OKAY -> SUSPECT
                      okay := non_neg_integer()},   %% REOPEN -> OKAY
-         codec :: #{decode_format := false,
+         codec :: #{decode_format := none,
                     string_decode := false,
                     strict_arities => diameter:strict_arities(),
                     strict_mbit := boolean(),
@@ -157,7 +157,7 @@ i({Ack, T, Pid, {Opts,
                                  string_decode,
                                  rfc,
                                  ordered_encode],
-                                SvcOpts#{decode_format := false,
+                                SvcOpts#{decode_format := none,
                                          string_decode := false,
                                          ordered_encode => false})}.
 
diff --git a/lib/diameter/src/transport/diameter_sctp.erl b/lib/diameter/src/transport/diameter_sctp.erl
index 8de19e904e..4eb3379d59 100644
--- a/lib/diameter/src/transport/diameter_sctp.erl
+++ b/lib/diameter/src/transport/diameter_sctp.erl
@@ -102,6 +102,7 @@
          streams  :: {uint(), uint()}      %% {InStream, OutStream} counts
                    | undefined,
          os = 0   :: uint(),               %% next output stream
+         rotate = 1 :: boolean() | 0 | 1,  %% rotate os?
          packet = true :: boolean()        %% legacy transport_data?
                         | raw,
          message_cb = false :: false | diameter:eval(),
@@ -692,11 +693,16 @@ send(#diameter_packet{transport_data = {outstream, SId}}
      = S) ->
     send(SId rem OS, Msg, S);
 
-%% ... or not: rotate through all streams.
-send(Msg, #transport{streams = {_, OS},
+%% ... or not: rotate when sending on multiple streams ...
+send(Msg, #transport{rotate = true,
+                     streams = {_, OS},
                      os = N}
           = S) ->
-    send(N, Msg, S#transport{os = (N + 1) rem OS}).
+    send(N, Msg, S#transport{os = (N + 1) rem OS});
+
+%% ... or send on the only stream available.
+send(Msg, S) ->
+    send(0, Msg, S).
 
 %% send/3
 
@@ -764,7 +770,7 @@ recv({[#sctp_sndrcvinfo{assoc_id = Id}], _Bin}
 %% Inbound Diameter message.
 recv({[#sctp_sndrcvinfo{}], Bin} = Msg, S)
   when is_binary(Bin) ->
-    message(recv, Msg, S);
+    message(recv, Msg, recv(S));
 
 recv({_, #sctp_shutdown_event{}}, _) ->
     stop;
@@ -784,6 +790,25 @@ recv({_, #sctp_paddr_change{}}, _) ->
 recv({_, #sctp_pdapi_event{}}, _) ->
     ok.
 
+%% recv/1
+%%
+%% Start sending unordered after the second reception, so that an
+%% outgoing CER/CEA will arrive at the peer before another request.
+
+recv(#transport{rotate = B} = S)
+  when is_boolean(B) ->
+    S;
+
+recv(#transport{rotate = 0, streams = {_,N}, socket = Sock} = S) ->
+    ok = inet:setopts(Sock, [{sctp_default_send_param,
+                              #sctp_sndrcvinfo{flags = [unordered]}}]),
+    S#transport{rotate = 1 < N};
+
+recv(#transport{rotate = N} = S) ->
+    S#transport{rotate = N-1}.
+
+%% publish/4
+
 publish(T, Ref, Id, Sock) ->
     true = diameter_reg:add_new({?MODULE, T, {Ref, {Id, Sock}}}),
     putr(?INFO_KEY, {gen_sctp, Sock}).  %% for info/1
diff --git a/lib/diameter/test/diameter_traffic_SUITE.erl b/lib/diameter/test/diameter_traffic_SUITE.erl
index 6f30055a0a..8f2549c8b6 100644
--- a/lib/diameter/test/diameter_traffic_SUITE.erl
+++ b/lib/diameter/test/diameter_traffic_SUITE.erl
@@ -49,6 +49,7 @@
          send_protocol_error/1,
          send_experimental_result/1,
          send_arbitrary/1,
+         send_proxy_info/1,
          send_unknown/1,
          send_unknown_short/1,
          send_unknown_mandatory/1,
@@ -114,6 +115,8 @@
 %% diameter_{tcp,sctp} callbacks
 -export([message/3]).
 
+-include_lib("kernel/include/inet_sctp.hrl").
+
 -include("diameter.hrl").
 -include("diameter_gen_base_rfc3588.hrl").
 -include("diameter_gen_base_accounting.hrl").
@@ -135,6 +138,7 @@
 
 -define(A, list_to_atom).
 -define(L, atom_to_list).
+-define(B, iolist_to_binary).
 
 %% Don't use is_record/2 since dictionary hrl's aren't included.
 %% (Since they define conflicting records with the same names.)
@@ -154,7 +158,7 @@
 -define(ENCODINGS, [list, record, map]).
 
 %% How to decode incoming messages.
--define(DECODINGS, [record, false, map, list, record_from_map]).
+-define(DECODINGS, [record, none, map, list, record_from_map]).
 
 %% Which dictionary to use in the clients.
 -define(RFCS, [rfc3588, rfc6733, rfc4005]).
@@ -442,6 +446,7 @@ tc() ->
      send_protocol_error,
      send_experimental_result,
      send_arbitrary,
+     send_proxy_info,
      send_unknown,
      send_unknown_short,
      send_unknown_mandatory,
@@ -507,6 +512,7 @@ start_services(Config) ->
                                      | ?SERVICE(SN, Grp)]),
     ok = diameter:start_service(CN, [{traffic_counters, bool()},
                                      {sequence, ?CLIENT_MASK},
+                                     {decode_format, map},
                                      {strict_arities, decode}
                                      | ?SERVICE(CN, Grp)]).
 
@@ -533,7 +539,7 @@ add_transports(Config) ->
                          | server_apps()]
                         ++ [{spawn_opt, {erlang, spawn, []}} || CS]),
     Cs = [?util:connect(CN,
-                        [T, {sender, CS}],
+                        [T, {sender, CS} | client_opts(T)],
                         LRef,
                         [{id, Id}
                          | client_apps(R, [{'Origin-State-Id', origin(Id)}])])
@@ -543,6 +549,14 @@ add_transports(Config) ->
              Id <- [{D,E}]],
     ?util:write_priv(Config, "transport", [LRef | Cs]).
 
+client_opts(tcp) ->
+    [];
+client_opts(sctp) ->
+    [{sctp_initmsg, #sctp_initmsg{num_ostreams = N,
+                                  max_instreams = 5}}
+     || N <- [rand:uniform(8)],
+        N =< 6].
+
 server_apps() ->
     B = have_nas(),
     [{applications, [diameter_gen_base_rfc3588,
@@ -684,6 +698,19 @@ send_arbitrary(Config) ->
         = call(Config, Req),
     "XXX" = string(V, Config).
 
+%% Send Proxy-Info in an ASR that the peer answers with 3xxx, and
+%% ensure that the AVP is returned.
+send_proxy_info(Config) ->
+    H0 = ?B(?util:unique_string()),
+    S0 = ?B(?util:unique_string()),
+    Req = ['ASR', {'Proxy-Info', #{'Proxy-Host'  => H0,
+                                   'Proxy-State' => S0}}],
+    ['answer-message' | #{'Result-Code' := 3999,
+                          'Proxy-Info' := [#{'Proxy-Host' := H,
+                                             'Proxy-State' := S}]}]
+        = call(Config, Req),
+    [H0, S0] = [?B(X) || X <- [H,S]].
+
 %% Send an unknown AVP (to some client) and check that it comes back.
 send_unknown(Config) ->
     Req = ['ASR', {'AVP', [#diameter_avp{code = 999,
@@ -707,12 +734,12 @@ send_unknown_short(Config, M, RC) ->
                                          data = <<17>>}]}],
     ['ASA' | #{'Session-Id' := _,
                'Result-Code' := RC,
-               'Failed-AVP' := Avps}]
+               'Failed-AVP' := [#{'AVP' := [Avp]}]}]
         = call(Config, Req),
-    [[#diameter_avp{code = 999,
-                    is_mandatory = M,
-                    data = <<17, _/binary>>}]] %% extra bits from padding
-        = failed_avps(Avps, Config).
+    #diameter_avp{code = 999,
+                  is_mandatory = M,
+                  data = <<17, _/binary>>} %% extra bits from padding
+        = Avp.
 
 %% Ditto but set the M flag.
 send_unknown_mandatory(Config) ->
@@ -721,12 +748,12 @@ send_unknown_mandatory(Config) ->
                                          data = <<17>>}]}],
     ['ASA' | #{'Session-Id' := _,
                'Result-Code' := ?AVP_UNSUPPORTED,
-               'Failed-AVP' := Avps}]
+               'Failed-AVP' := [#{'AVP' := [Avp]}]}]
         = call(Config, Req),
-    [[#diameter_avp{code = 999,
-                    is_mandatory = true,
-                    data = <<17>>}]]
-        = failed_avps(Avps, Config).
+    #diameter_avp{code = 999,
+                  is_mandatory = true,
+                  data = <<17>>}
+        = Avp.
 
 %% Ditto, and point the AVP length past the end of the message. Expect
 %% 5014 instead of 5001.
@@ -741,13 +768,13 @@ send_unexpected_mandatory_decode(Config) ->
                                          data = <<12:32>>}]}],
     ['ASA' | #{'Session-Id' := _,
                'Result-Code' := ?AVP_UNSUPPORTED,
-               'Failed-AVP' := Avps}]
+               'Failed-AVP' := [#{'AVP' := [Avp]}]}]
         = call(Config, Req),
-    [[#diameter_avp{code = 27,
-                    is_mandatory = true,
-                    value = 12,
-                    data = <<12:32>>}]]
-        = failed_avps(Avps, Config).
+    #diameter_avp{code = 27,
+                  is_mandatory = true,
+                  value = 12,
+                  data = <<12:32>>}
+        = Avp.
 
 %% Try to two Auth-Application-Id in ASR expect 5009.
 send_too_many(Config) ->
@@ -755,11 +782,11 @@ send_too_many(Config) ->
 
     ['ASA' | #{'Session-Id' := _,
                'Result-Code' := ?TOO_MANY,
-               'Failed-AVP' := Avps}]
+               'Failed-AVP' := [#{'AVP' := [Avp]}]}]
         = call(Config, Req),
-    [[#diameter_avp{name = 'Auth-Application-Id',
-                    value = 44}]]
-        = failed_avps(Avps, Config).
+    #diameter_avp{name = 'Auth-Application-Id',
+                  value = 44}
+        = Avp.
 
 %% Send an containing a faulty Grouped AVP (empty Proxy-Host in
 %% Proxy-Info) and expect that only the faulty AVP is sent in
@@ -771,12 +798,11 @@ send_grouped_error(Config) ->
                                    {'Proxy-State', ""}]]}],
     ['ASA' | #{'Session-Id' := _,
                'Result-Code' := ?INVALID_AVP_LENGTH,
-               'Failed-AVP' := Avps}]
+               'Failed-AVP' := [#{'AVP' := [Avp]}]}]
         = call(Config, Req),
-    [[#diameter_avp{name = 'Proxy-Info', value = V}]]
-        = failed_avps(Avps, Config),
-    {Empty, undefined, []} = proxy_info(V, Config),
-    <<0>> = iolist_to_binary(Empty).
+    #diameter_avp{name = 'Proxy-Info', value = #{'Proxy-Host' := H}}
+        = Avp,
+    <<0>> = ?B(H).
 
 %% Send an STR that the server ignores.
 send_noreply(Config) ->
@@ -829,9 +855,8 @@ send_invalid_avp_length(Config) ->
                'Result-Code' := ?INVALID_AVP_LENGTH,
                'Origin-Host' := _,
                'Origin-Realm' := _,
-               'Failed-AVP' := Avps}]
-        = call(Config, Req),
-    [[_]] = failed_avps(Avps, Config).
+               'Failed-AVP' := [#{'AVP' := [_]}]}]
+        = call(Config, Req).
 
 %% Send a request containing 5xxx errors that the server rejects with
 %% 3xxx.
@@ -1042,29 +1067,6 @@ send_anything(Config) ->
 
 %% ===========================================================================
 
-failed_avps(Avps, Config) ->
-    #group{client_dict = D} = proplists:get_value(group, Config),
-    [failed_avp(D, T) || T <- Avps].
-
-failed_avp(nas4005, {'nas_Failed-AVP', As}) ->
-    As;
-failed_avp(_, #'diameter_base_Failed-AVP'{'AVP' = As}) ->
-    As.
-
-proxy_info(Rec, Config) ->
-    #group{client_dict = D} = proplists:get_value(group, Config),
-    if D == nas4005 ->
-            {'nas_Proxy-Info', H, S, As}
-                = Rec,
-            {H,S,As};
-       true ->
-            #'diameter_base_Proxy-Info'{'Proxy-Host' = H,
-                                        'Proxy-State' = S,
-                                        'AVP' = As}
-                = Rec,
-            {H,S,As}
-    end.
-
 group(Config) ->
     #group{} = proplists:get_value(group, Config).
 
@@ -1105,12 +1107,12 @@ origin(N) ->
 decode(record) -> 0;
 decode(list)   -> 1;
 decode(map)    -> 2;
-decode(false)  -> 3;
+decode(none)   -> 3;
 decode(record_from_map) -> 4;
 decode(0) -> record;
 decode(1) -> list;
 decode(2) -> map;
-decode(3) -> false;
+decode(3) -> none;
 decode(4) -> record_from_map.
 
 encode(record) -> 0;
@@ -1157,16 +1159,17 @@ to_map(#diameter_packet{header = H, msg = Rec},
 
 %% No record decode: do it ourselves.
 to_map(#diameter_packet{header = H,
-                        msg = false,
+                        msg = Name,
                         bin = Bin},
-      #group{server_decoding = false,
+      #group{server_decoding = none,
              strings = B}) ->
     Opts = #{decode_format => map,
              string_decode => B,
              strict_mbit => true,
              rfc => 6733},
-    #diameter_packet{msg = [_MsgName | _Map] = Msg}
+    #diameter_packet{msg = [MsgName | _Map] = Msg}
         = diameter_codec:decode(dict(H), Opts, Bin),
+    {MsgName, _} = {Name, Msg},  %% assert
     Msg.
 
 dict(#diameter_header{application_id = Id,
@@ -1534,24 +1537,23 @@ answer(Pkt, Req, _Peer, Name, #group{client_dict = Dict0}) ->
     #diameter_packet{header = H, msg = Ans, errors = Es} = Pkt,
     ApplId = app(Req, Name, Dict0),
     #diameter_header{application_id = ApplId} = H,  %% assert
-    Dict = dict(Ans, Dict0),
-    rec_to_map(answer(Ans, Es, Name), Dict).
+    answer(Ans, Es, Name).
 
 %% Missing Result-Code and inappropriate Experimental-Result-Code.
-answer(Rec, Es, send_experimental_result) ->
+answer(Ans, Es, send_experimental_result) ->
     [{5004, #diameter_avp{name = 'Experimental-Result'}},
      {5005, #diameter_avp{name = 'Result-Code'}}]
         =  Es,
-    Rec;
+    Ans;
 
 %% An inappropriate E-bit results in a decode error ...
-answer(Rec, Es, send_bad_answer) ->
+answer(Ans, Es, send_bad_answer) ->
     [{5004, #diameter_avp{name = 'Result-Code'}} | _] = Es,
-    Rec;
+    Ans;
 
 %% ... while other errors are reflected in Failed-AVP.
-answer(Rec, [], _) ->
-    Rec.
+answer(Ans, [], _) ->
+    Ans.
 
 app(_, send_unsupported_app, _) ->
     ?BAD_APP;
@@ -1733,6 +1735,11 @@ request(['ACR' | #{'Accounting-Record-Number' := 4}],
                              {'Origin-Realm', OR}],
     {reply, Ans};
 
+%% send_proxy_info
+request(['ASR' | #{'Proxy-Info' := _}],
+        _) ->
+    {protocol_error, 3999};
+
 request(['ASR' | #{'Session-Id' := SId} = Avps],
         #diameter_caps{origin_host = {OH, _},
                        origin_realm = {OR, _}}) ->